Dissertations / Theses on the topic 'Copper-plate'
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1
Ashton, Mark. "Behaviour of metals as a function of strain-rate and temperature." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/10449.
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Five materials, copper (two versions), iron, and armour plate steel (two versions) have been tested at different strain-rates and temperatures. All tests were in compression. The materials were studied to provide experimental data for input into hydrocode models of armour behaviour by the Defence Research Agency, Fort Halstead. A wide selection of metals was examined so that comparisons could be drawn between modelling the behaviour of face centred and body centred cubic metals, and to carry out a broader investigation into how the results obtained were affected by the test methods. Experiments were performed at temperatures from -100°C to 20°C and mean plastic strain-rates from 10-3 to 103 S-l, using a Split Hopkinson Pressure Bar (SHPB) system for high strain-rates and a Hounsfield 50 kN machine for quasistatic conditions. The stress-strain behaviour of the materials as a function of temperature and strain-rate was then determined. The effects of interfacial friction on the measured compreSSlve properties of copper and the armour plate steels have been investigated. Since the coefficient of friction was the critical parameter, ring tests were carried out and the Avitzur analysis applied. In general, the coefficient of friction decreased with increasing strain-rate and temperature. The tested specimen's appearance indicated the same friction trends. Hydrocode modelling of the SHPB system produced corrections to the flow stress, to compensate for interfacial friction, that agree well with those predicted by the Avitzur analysis. Deformed finite element mesh plots analysed in conjunction with barrelled specimens have given a clearer insight into the mechanisms of interfacial friction. The Armstrong-Zerilli constitutive models have been applied to copper, iron and armour plate steel results corrected for thermal softening and specimen-platen interfacial friction. These models have been shown to provide a reasonable description of the materials' behaviour. The research investigation has shown that in order to obtain fundamental stressstrain behaviour of the materials, then corrections must be applied, which can be quite significant. These corrections must take into account the effects of material thermal softening and the specimen-platen interfacial friction.
2
Jordan, Rainer, Tao Zhang, Yunhao Du, Felix Müller, and Ihsan Amin. "Surface-initiated Cu(0) mediated controlled radical polymerization (SI-CuCRP) using a copper plate." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-188989.
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Surface engineering with polymer brushes has become one of the most versatile techniques to tailor surface properties of substrates for a broad variety of (bio-) technological applications. We report on a new facile approach to prepare defined and dense polymer brushes on planar substrates by surface-initiated Cu(0) mediated controlled radical polymerization (SI-CuCRP) of numerous vinyl monomers using a copper plate at room temperature. The fabrication of a variety of homo-, block, gradient and patterned polymer brushes as well as polymer brush arrays is demonstrated. The SI-CuCRP was found to be strictly surface-confined, of highly living character, proceeds remarkably fast and results in polymer brushes of very high grafting densities. The brush layer thickness can be modulated by the polymerization time or by the distance of the copper plate to the modified substrate. As the copper plate can be reused multiple times, no additional copper salts are added and only minimal amount of chemicals is needed, the simple and low-cost experimental conditions allows researchers from various fields to prepare tailored polymer brush surfaces for their needs.
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Suka, Akira. "Microstructure and mechanical properties of high copper HSLA-100 steel in 2-inch plate form." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23957.
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Approved for public release; distribution is unlimitedThe microstructure and mechanical properties of highly welda ble high copper HSLA-100 steel in two-inch (50 mm) plate form were investigated in this work. The mechanical property data showed that the steel in the as-quenched and aged conditions not only met the mechanical property specifications of the Navy for HSLA (HY) 100 steels but also satisfied the requirements for HY-130 steels. Optical, scanning and transmission electron microscope studies of the as-quenched plate indicated that the microstructure was a mixture of lath martensite/retained austenite and bainitic ferrite, which is typical of these steels. On aging this microstructure developed the tempered structures usually encountered in HSLA steels. This investigation concludes that: Increased copper HSLA steel meets all the mechanical property specifications of Navy HSLA-100 ksi yield strength steel regardless of heat treatment and plate thickness (up to 50 mm thickness). High copper HSLA-100 steel in 50 mm plate form can fulfill all the mechanical property requirements of Navy 130 ksi yield strength steel with an appropriate temper. The microstructures formed with various heat treatments are consistent with the HSLA-100 CCT diagram. Increasing copper in HSLA-100 steel also increases the toughness as well as the strength, though the dynamics of this process is not clear.
4
Mirhi, Mohamad H. (Mohamad Hussein). "Gypsum scale formation on a heated copper plate under natural convection conditions and produced water remediation technologies review." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81612.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 175-181).
Scaling or crystallization fouling of unwanted salts is one of the most challenging and expensive problems encountered in different applications such as heat exchangers and thermal water treatment technologies. Formation of dihydrated calcium sulfate scale, also known as gypsum, on a heated copper plate is studied in lab. The copper plate, held at a given temperature, is immersed in a supersaturated solution of calcium sulfate prepared at a given concentration. The flow conditions are governed by natural convection. A parametric study, in which surface temperature and the degree of supersaturation are varied, is set up and a scale inception time curve is plotted. No scale is observed at a supersaturation index smaller or equal to 1.4. Both higher temperatures and higher concentrations result in faster scale induction; however, the effect of temperature is more significant at lower degrees of supersaturation. SEM images of scale samples show needle-like crystals, the thinnest of which formed at a supersaturation index of 2.0. The classical nucleation theory of Mullin provides an excellent fit for the results. Interfacial energies calculated out of this model are in the reported ranges.
by Mohamad H. Mirhi.
S.M.
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Walter, Sunette. "Characterization of heterotrophic plate count (HPC) bacteria from biofilm and bulk water samples from the Potchefstroom drinking water distribution system / by S. Walter." Thesis, North-West University, 2009. http://hdl.handle.net/10394/4977.
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The presence of heterotrophic plate count (HPC) bacteria in drinking water distribution systems is usually not considered harmful to the general consumer. However, precautions must be taken regarding the immunocompromised. All water supply authorities in South Africa are lawfully required to provide consumers with high-quality drinking water that complies with South African-and international standards. This study mainly focused on the isolation, identification and characterization of HPC and other bacteria from biofilm-and bulk water samples from two sampling points located within the Potchefstroom drinking water distribution system. Based on five main objectives set out in this study, results indicated that the bulk water at the J.S. van der Merwe building was of ideal quality fit for lifetime consumption. Application of enrichment-and selective media allowed for the isolation of 12 different bacterial morphotypes. These were identified by way of biochemical-and molecular methods as Bacillus cereus, Bacillus subtilis, Brevundimonas spp., Clostridiaceae, Corynebacterium renale, Flavobacteriaceae, Kytococcus sedentarius, Leuconostoc lactic, Lysinibacillus sphaericus, Pseudomonas spp., Staphylococcus aureus and Staphylococcus capitis. The greatest diversity of bacteria was detected early autumn 2008, while the lowest diversity occurred during mid-winter 2007. Bacillus cereus, Kytococcus sedentarius and Staphylococcus capitis displayed potential pathogenic properties on blood agar. Kytococcus sedentarius could be classified as potentially the most pathogenic among the isolates. All isolates displayed multiple-resistant patterns towards tested antibiotics. Corynebacterium renale and Staphylococcus aureus were least resistant bacterial species and Lysinibacillus sphaericus the most resistant. All isolates were susceptible to ciprofloxacin (CIP) and streptomycin (S), but most were resistant to erythromycin (E). Transmission electron microscopy (TEM) allowed for detailed examination of Brevundimonas spp., Pseudomonas spp. and Staphylococcus spp. The capability of Brevundimonas spp. to produce slime and store nutrients within inclusion bodies, suggests the ability of this bacterium to form biofilm and persist in the drinking water for prolonged periods. Despite the inhibitory or toxic effect of copper against bacterial growth, scanning electron microscopy (SEM) revealed the presence of biofilms as well as diatoms on red-copper coupons. Biofilm activity was also observed on reverse-osmosis (RO) filters. Since corrosion was evident on red-copper coupons, it is recommended that prospective studies also look into the significance of microbial induced corrosion (MIC) within the Potchefstroom drinking water distribution system. Other prospects include determining minimum inhibitory concentrations of isolates against antibiotics and the application of culture independent methods such as SSCP and DGGE to investigate biofilm development. The use of diatoms as an index of the drinking water quality is also suggested.Thesis (M.Sc. (Environmental Science))--North-West University, Potchefstroom Campus, 2010.
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Tejpal, Jyoti. "The use of metal and metal oxide nanoparticles against biofilms." Thesis, De Montfort University, 2016. http://hdl.handle.net/2086/13114.
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The persistence of biofilms in hospital settings are associated with Healthcare Associated Infections (HCAI), causing increased morbidity, mortality and healthcare costs. The resistance of biofilms against commonly used hospital disinfectants has been well reported. Metal and metal oxide nanoparticles (NP) such as silver (Ag), copper (Cu), zinc oxide (ZnO) and copper oxide (CuO) exhibit antimicrobial properties against various pathogens. Methods: Biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus in a Centre for Disease Control (CDC) biofilm reactor and a 96 well plate was compared. A three stage approach including Minimum Biofilm Reduction Concentration (MBRC), R2 values and log(10) reductions was used to assess the efficacy of Ag and ZnO NPs both alone and in combination against P. aeruginosa and S. aureus biofilms. Atomic Absorption Spectroscopy (AAS), Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) was used to further assess the antimicrobial ability of the metal and metal oxide NPs. The prevention of P. aeruginosa and S. aureus adherence on Ag and ZnO thin film coating on silicon (Si) surfaces was also investigated, as well as icaC, ebpS and fnbB gene expression in S. aureus biofilms. Results: The CDC biofilm reactor demonstrated to be the most effective method for P. aeruginosa and S. aureus biofilm production in comparison to 96 well plates, with lower standard errors of the mean (SE) and higher replicability. Individual MBRC of ZnO and Ag NPs in suspension were 256 and 50 µg/ml for P. aeruginosa and 16 and 50 µg/ml for S. aureus respectively. The concentrations in combination were reduced by at least a half, with concentrations of 32/25 µg/ml of ZnO/Ag NPs in suspension resulting in a significant (p ≤0.05) reduction of 3.77 log(10) against P. aeruginosa biofilms and 8/12 µg/ml of ZnO/Ag NPs in suspension resulted in a 3.91 log(10) (p ≤0.05) against S. aureus biofilms. Both combinations showed an additive effect. Time point analysis confirmed that a 24 hour treatment is vital for any significant (p ≤0.05) antimicrobial activity. AAS data suggested that the Ag+ ions quenched Zn2+ ions, therefore the antimicrobial efficacy of the combination is mainly due to Ag+ ions. Damage of the biofilms from Ag and ZnO NPs was observed in the SEM imaging and energy dispersive X-ray (EDX) analysis confirmed the adherence of Zn and Ag within the biofilms. CLSM imaging showed dead (red) cells of P. aeruginosa and S. aureus biofilms throughout the depth of the biofilm. P. aeruginosa formation was reduced by 1.41 log(10) and 1.43 log(10) on Ag and ZnO thin film coatings respectively. For S. aureus, a reduction of 1.82 log(10) and 1.65 log(10) was obtained for Ag and ZnO coating respectively. Only low levels of ribonucleic acid (RNA) were achieved so no further gene analysis could occur. Conclusion: Reductions of ≥3 log(10) were observed for P. aeruginosa and S. aureus biofilm treatment with ZnO/Ag NP suspensions. It can be concluded that the ZnO/Ag NP suspensions had greater antimicrobial activity than Ag and ZnO coated surfaces owing to large concentrations of Ag+ and Zn2+ ions acting upon the biofilms. The slower release of ions from coated surfaces suggest an inadequate concentration of ions in the media, which are therefore unable to prevent biofilm formation as rapidly as NP suspensions, however provide a sustained release of ions over time. The results from this investigation propose that Ag and ZnO NPs in suspension could be a potential alternative to disinfectants for use in nosocomial environments against P. aeruginosa and S. aureus biofilms.
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Buřič, Jan. "Vnitřní prostředí a výplně otvorů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-239950.
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The aim this diploma thesis is the design of heating and hot water in the building of a primary school in Trhové Sviny. The first part dealt with the issue of indoor environment and windows. The second part deals with a separate proposal heating and hot water in primary school. As a heat source was designed gas boiler, the second variant hot transfer station. The third part consists of technical reports and drawings of the specified object. The fourth part deals with the assessment of surface condensation on the surface of the window panes.
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Takeda, Sho. "A Study of the Consolidation Process of Cu from Powder to Plate by Compression Shearing Method." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEC047.
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Compression shearing method at room temperature (COSME-RT)’ est une technique de moulage de matériaux (en particulier de métaux) de la poudre à la plaque en appliquant une force biaxiale simultanée à la température ambiante et dans une atmosphère ambiante. COSME-RT diffère des techniques de moulage conventionnelles en ce sens qu'il peut fabriquer des matériaux sans processus de chauffage et peut ainsi développer de nouveaux matériaux qui ne peuvent pas être formés par des procédés conventionnels. Cependant, le mécanisme de consolidation des matériaux de COSME-RT n’a pas été clarifié en raison de la difficulté de contrôler le processus. Pour contrôler le processus de consolidation des matériaux métalliques avec COSME-RT, j'ai tenté deux expériences visant à contrôler la force de cisaillement: (1) la suppression de la force de cisaillement en dispersant des particules solides de lubrifiant dans des particules de poudre de Cu; et (2) le test de frottement unidirectionnel sur l'échantillon de poudre comprimée uniaxiale pour créer et observer le changement de la condition de liaison dans la direction de la profondeur de l'échantillon. En conséquence, j'ai réussi à acquérir de nouvelles connaissances sur le processus de consolidation des plaques de Cu de poudre de COSME-RT et à construire le nouveau modèle de consolidation du Cu de COSME-RTCompression shearing method at room temperature (COSME-RT) is a molding technique for materials (especially metals) from powder to plate by applying simultaneous biaxial force at room temperature and an ambient atmosphere. COSME-RT differs from conventional molding techniques in that it can fabricate materials without a heating process and can thus develop new materials that cannot be formed by conventional methods. However, the consolidation mechanism of materials by COSME-RT has not been clarified because of the difficulty of controlling the process. To control the consolidation process of metal materials by COSME-RT, I attempted two experiments to control the shearing force: (1) the suppression of the shearing force by dispersing solid lubricant particles into Cu powder particles; and (2) the unidirectional friction test on the uniaxial compressed powder sample to create and observe the change of the bonding condition in the depth direction of the sample. As a result, I successfully obtained new knowledge about the consolidation process of Cu plate from powder by COSME-RT and built the new consolidation model of Cu by COSME-RT
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Furberg, Richard. "Enhanced Boiling Heat Transfer on a Dendritic and Micro-Porous Copper Structure." Doctoral thesis, KTH, Tillämpad termodynamik och kylteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-47538.
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A novel surface structure comprising dendritically ordered nano-particles of copper was developed during the duration of this thesis research project. A high current density electrodeposition process, where hydrogen bubbles functioned as a dynamic mask for the materials deposition, was used as a basic fabrication method. A post processing annealing treatment was further developed to stabilize and enhance the mechanical stability of the structure. The structure was studied quite extensively in various pool boiling experiments in refrigerants; R134a and FC-72. Different parameters were investigated, such as; thickness of the porous layer, presence of vapor escape channels, annealed or non-annealed structure. Some of the tests were filmed with a high speed camera, from which visual observation were made as well as quantitative bubble data extracted. The overall heat transfer coefficient in R134a was enhanced by about an order of magnitude compared to a plain reference surface and bubble image data suggests that both single- and two-phase heat transfer mechanisms were important to the enhancement. A quantitative and semi-empirical boiling model was presented where the main two-phase heat transfer mechanism inside the porous structure was assumed to be; micro-layer evaporation formed by an oscillating vapor-liquid meniscus front with low resistance vapor transport through escape channels. Laminar liquid motion induced by the oscillating vapor front was suggested as the primary single-phase heat transfer mechanism. The structure was applied to a standard plate heat exchanger evaporator with varying hydraulic diameter in the refrigerant channel. Again, a 10 times improved heat transfer coefficient in the refrigerant channel was recorded, resulting in an improvement of the overall heat transfer coefficient with over 100%. A superposition model was used to evaluate the results and it was found that for the enhanced boiling structure, variations of the hydraulic diameter caused a change in the nucleate boiling mechanism, which accounted for the largest effect on the heat transfer performance. For the standard heat exchanger, it was mostly the convective boiling mechanism that was affected by the change in hydraulic diameter. The structure was also applied to the evaporator surface in a two-phase thermosyphon with R134a as working fluid. The nucleate boiling mechanism was found to be enhanced with about 4 times and high speed videos of the enhanced evaporator reveal an isolated bubble flow regime, similar to that of smooth channels with larger hydraulic diameters. The number and frequency of the produced bubbles were significantly higher for the enhanced surface compared to that of the plain evaporator. This enhanced turbulence and continuous boiling on the porous structure resulted in decreased oscillations in the thermosyphon for the entire range of heat fluxes.QC 20111111
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Mašek, Jakub. "Funkční zkouška tepelného spínače pro prostředí planety Mars." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254304.
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Diplomová práce se zabývá studiem projektu tepelného spínače a dosažených výsledků. Zaměřuje se především na vývoj zařízení pro zkoušení tepelného spínače v podmínkách odpovídající prostředí planety Marsu. První část práce se zabývá především popisem vývoje zkušební komory určené pro simulaci extrémních podmínek, tj. nízkého tlaku a teplot, od předběžného návrhu až po konečnou podobu komory, která bude použita pro předepsané zkoušky. Práce popisuje také důvody úprav některých částí komory a uvádí návrhy řešení nepředvídaných událostí, které vznikly v průběhu testů. Cílem druhé části práce je návrh kampaně pro zkoušení tepelného spínače od úvodních zkoušek ověření základní funkčnosti komory, přes ověření vlastností a nastavení všech systémů měřícího zařízení, až po zkoušky na prvních vzorcích a závěrečném kvalifikačním modelu tepelného spínače. Dále se práce zaměřuje na postup vyhodnocení naměřených dat a jevů, které jej ovlivňují. Kalibrační zkoušky zařízení, systémů a postupu vyhodnocení naměřených dat, které byly provedeny na speciálně navržených náhradních vzorcích, jsou téměř u konce. Jakmile budou výsledky schváleny, zkušební komora i navržené postupy měření budou připraveny pro požadované zkoušení vzorků tepelného spínače.
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Wu, Sheng-Chun, and 吳聖君. "Synthesis and Characterization of Copper Plate." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/18763427320307350943.
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碩士明新科技大學
化學工程與材料科技系
99
The polyol method is used to synthesize a uniform copper plate in this study. The sodium hypophosphite and tetra-N-butylammonium were used as reducing agent and template in this study, respectively. The polyvinylpyrrolidone plays an important role as stabilizer and protector. The experimental results show that the concentrations of PVP and TNBCl affect the shape of copper plate. When the concentration of copper is higher than 0.04M, the amount of copper plate increased with increasing TNBCl concentration. Similarly, varied PVP concentration also has same effect. As shown in above, the parameters of 0.5M PVP and 0.06M TNBCl can be used for synthesizing copper plates. Furthermore, higher or lower reaction temperature from reference level of 90℃ also inhibits copper plate formed. Similarly, increasing or decreasing concentration of reducing agent could cause copper ion concentration varied so that spherical copper particles formed. An optimal condition for the synthesis of copper plate is developed and found to be 0.5M polyvinylpyrrolidone, 0.06M tetra-N-butylammonium, 1.48M copper nitrate, 4.45M reducing agent and 90℃ reaction temperature.
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Po-HungChou and 周柏宏. "LED Resin Copper Plate Polishing Operation Optimization." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/syner2.
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Chang, Jui-En, and 張瑞恩. "Fabrication of the Copper/ Aluminum Alloy Clad Plate Using Friction Stir Welding." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/25r7aa.
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碩士國立中山大學
機械與機電工程學系研究所
102
This study tried to join copper sheet (3 mm thick) on aluminum alloy plate (7 mm thick) by friction stir lap welding using a pinless tool with 16 mm diameter at zero tilt angle. First, in order to prevent the oxidation of the joining surface in the welding process, an aluminum sheet (10 mm thick) was machined to form a rectangular slot of 25 mm wide on its center region to accommodate a copper sheet (3 mm thick). Four edges of copper sheet were welded by the friction stir butt welding using a pinless tool as a pretreatment. Second, effects of rotational speed and plunge depth on the quality of the welded joint by the friction stir spot welding were investigated. Experimental results showed that the fractured thickness of aluminum alloy adhered on the copper sheet increased with increasing rotational speed of a plunge depth of 0.2 mm, and with increasing plunge depth at a rotational speed of 1000 rpm. According to the above results to select the rotational speed and plunge depth, effect of welding speed on the shear strength and the measured temperature in the joint line at a distance of 10 mm from top surface of workpiece was investigated in the friction stir lap welding. Experimental results showed that the shear strength of welded specimen was stronger at low welding speed, but the quality of the welded joint was unstable at the welding speed of 32 mm/min. The multiple passes of copper sheet can be successfully joined on the aluminum alloy plate using the rotational speed of 1000 rpm, plunge depth of 0.3 mm, and welding speed of 60 mm/min.
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Wu, Chih-ying, and 吳致穎. "Studies on the Friction Stir Welding of Pure Copper Plate with 10 mm Thickness." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/69980945437025675902.
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碩士國立中山大學
機械與機電工程學系研究所
104
In this study, a traditional vertical milling machine with a load cell in the vertical direction is used to conduct a friction stir butt welding for the pure copper plates with the thickness of 10 mm. Under the welding conditions of a spindle speed of 800 rpm, feed rates from 45 to 140 mm/min, plunge depth of 1 mm, and tilt angle of 1.5°, the joint strength of copper plates, downward force, and welding temperature are investigated. Experimental results show that the welding temperature can achieve 870°C after the dwell time of nearly 20 seconds during the plunge process. The welding temperature increases to about 900 to 920°C with increasing dwell time, and then gradually achieves a saturation value. In the welding process, the maximum value of downward force remains about 20kN, and it is independent of the feed rate. The maximum value of welding temperature decreases from 830°C to 570°C with increasing feed rate. The failure strength of the joint decreases with increasing feed rate. The failure strength has a maximum value of about 178 MPa at the feed rate 45 mm/min, which is about 64% of the base material strength. Thus, the feed rate of 45 mm/min is suitable to butt weld copper plates with the thickness of 10 mm.
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Lee, Chen-Hau, and 李振豪. "Studies on Friction Stir Welding Characteristics of Pure Copper Plate with 20 mm Thickness." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/96ty66.
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碩士國立中山大學
機械與機電工程學系研究所
106
In this study, 20 mm thick pure copper plates were friction stir welded (FSW) by three different tool materials at tilt angle of 1.5°, tool rotating speed of 1000 rpm, and different feed speeds to investigate the effect of tool material and pin geometry on the pin deformation. In the FSW experiments, the downward force and the temperature were measured to record their time histories. Finally, effects of feed speed on the downward force, the temperature and the joint strength were investigated. The mechanical properties of the weld were discussed by observing the metallography of the fractured surface in the tensile test after welding. Experimental results show that the temperature achieved 870°C after dwell time of 10 seconds in the friction stir spot welding using three tool materials. The high-speed steel tool was obviously deformed after welding, and it was not suitable as a tool material. Inconel 600 and Nimonic 75 were selected as the materials with the tool reusability. The pin with the angle of 40° was easy to deform during FSW process due to less material at its tip. Moreover, the material at the bottom of the workpiece was not fully driven, resulting in insufficient backfilling of the material with void defects. Consequently, the pin with the angle of 30° was selected. Results showed that the tensile strength of the weld had no obvious variation under the feed speeds of 45~86 mm/min after FSW process. The top of workpieces could achieve more than 90% of tensile strength of pure copper, and the elongation could achieve more than 75% of base metal. Since stirring was less uneven at the bottom of workpieces, it had more than 80% of tensile strength, and the elongation could achieve more than 40% of base metal. In addition, the faster the feed speed, the slighter the hardness of the workpiece, due to the finer the grain in the stirring zone by observing the metallography of the weld.
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YU, Teng-Yung, and 游騰勇. "Explore Taguchi method for copper and stainless steel plate chemical analysis of ceramic glaze Comparison." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/62306677410143291458.
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碩士桃園創新技術學院
材料應用科技研究所
101
Ceramic is a boric acid salt or a mixture of low melting silicates glassy coating, and then add the metal oxide colorant, and by the heat energy to be attached to the metal carcass, also called enamel production methods. Because glass, ceramics, metal objects into the surface of the glaze firing, the artifacts are coated on the surface layer of vitreous, the three components of the coating mixture together for silicates, low-temperature glaze can be melted in the three phases of the between objects on the surface. View from the physical and chemical properties, which, similar to the composition of the glass, in addition to acid and alkali resistance, but is not conductive, insolubility, waterproof, airtight, to cover the thin metal solid surface, they seem to protect membrane as to prevent oxidation. Thesis sintering of copper metal and stainless steel sheet metal ceramic layer comparative study, based on the industry to provide the kiln temperature, mesh, metal thickness firing time and experience, with Taguchi L16 (45) orthogonal array obtain optimum copper plate and stainless steel sheet metal and low temperature sintering process mix glaze, systematic identify and determine the relationship between post-sintering; further experiments with chemical properties, such as salt spray test of the strength of adhesion, the use of Vickers hardness testing methods. MINITAB software application within the one-way ANOVA analysis to identify the significant process control factors. It can get the best sintered metal and ceramic glaze layer surface structure and elemental composition, in order to establish the optimization of process technology.
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Wang, Wei-Chun, and 王威鈞. "Application of Taguchi Method to C2680 Copper Alloy Plate Casting and Hot Rolling Process Optimization." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/egmwf4.
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碩士國立高雄科技大學
模具工程系
107
The study investigates the causes of the different casting and hot rolling conditions on different edge crack to slab casting of C2680 copper alloy. Different manufacturing process factors might cause C2680 copper alloy to have crack on the two sides of copper coil when it is calendaring. Therefore, the current study focuses on decreasing hot rolling edge crack with orthogonal arrays designed by Taguchi method (L934) and with four control factors brainstormed by the researcher. A: casting speed, B: the amount of cooling water, C: the heating temperature before hot rolling, D: the frequency of hot rolling. Then, the researcher set up the standards to do a crossover trial. Nine research analysis; each group being tested for three times; ninety final products for each test. The control factors of S/N ratio were calculated from by analyzing the research results with the smaller is better of S/N ratio. From such result, the researcher explored the level of influence of the control factor on and the most efficient group condition from the control factors on C2680 copper alloy hot rolling edge crack. Last, the researcher used ANOVA analysis to examine the F-test & Q-test and reliability of research results. The results show that the most efficient group condition from the control factors is “casting speed is 120 mm/min ; the amount of cooling water is 170 m3/hr ; the heating temperature before hot rolling is 850℃ ; the frequency of hot rolling is 21 times. The degree of influence & contribution of the control factor on the cracking of the hot rolling forming in decreasing order are the frequency of hot rolling > casting speed > the amount of cooling water > the heating temperature before hot rolling.
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JIAN, JHENG-YING, and 簡正穎. "Copper plate economy in traditional night market ：Ａ Case Study on Han River night market." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/bn45gu.
Full textAbstract:
碩士建國科技大學
數位媒體設計系暨媒體與遊戲設計研究所
107
The night market culture has become one of the indispensable itineraries for Taiwanese night entertainment. It is also a unique cultural and market trading activity in Taiwan. It is also an important itinerary for tourists to visit, and the snack food in the night market is more representative. Taiwan's most simple cultural spirit of the Dalits also shows local characteristics and history, and promotes emotional exchanges. In the related research on the collection of night markets, most of the researches on the study of the night market are biased towards exploring the night market and consumer experience. Very few traditional night markets are the research objects, and the management of the night market is very rare, so this study The purpose of this research is to study the motives of this study. Therefore, the purpose of this study is to explore the management of the night market in Fanxi Night Market and the vendors. How to successfully manage the operation of the Yanxi Night Market . This study used the qualitative research method to take the Yanxi Night Market as the research object, and conducted in-depth interviews with the managers and vendors of the night market, interviewing one manager and six vendors. Through relevant research methods to conduct relevant analysis and discussion, to understand the main success factors of the night market and consumer spending trends. The research results show that the key factors for the success of the dry-flow night market are good location, low repeatability of the booth, planning of traffic lines and ample parking spaces will not lead to the lack of parking spaces for people coming to the night market. The diversity of troubles and snacks; the recruitment method does not require too much advertising to attract all types of vendors, and as long as they have physical and mental disabilities, they will receive subsidies, one step by one. The spirit of footprints makes the dry river night market so large nowadays, plus the cleanliness of the internal environment and the public facilities are cleaned up so that the night market environment will not be messy. The parking lot also has administrators to manage the vehicles in and out, let the night market With a lot of peace of mind, the quality of the customer-oriented concept makes the Yanxi Night Market stand out and has become a familiar Taichung Night Market. Keywords: night market culture, diamond theory, management
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Yang, Hsuan-Cheng, and 楊軒政. "Enhancement of FC-72 pool boiling heat heat transfer and associated bubble characteristics over a small horizontal plate by placing copper strings above the plate." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/66324556453898208211.
Full textAbstract:
碩士國立交通大學
機械工程學系
99
An experiment is carried out here to investigate how the saturated pool boiling heat transfer of liquid FC-72 over a small horizontal heated copper plate ( ) is affected by placing flexible and movable fine copper strings above the plate surface, intending to explore the possible pool boiling heat transfer enhancement by the strings. The strings of uniform size are fixed only at their ends and are parallel with each other. In the experiment, the imposed heat flux is varied from 0.1 to 7 W/cm2, the diameter of strings from 79 to 254μm, the string-heated surface separation from 0 to 2 mm, and the length of the strings from 10 to 12 mm for the pitch of the strings fixed at 1 mm. The measured data are presented in terms of the boiling curves and boiling heat transfer coefficients for the heating surface with and without the installation of the strings. Effects of the experimental parameters on the possible boiling heat transfer enhancement are examined in detail. The data obtained from the present study for the saturated pool boiling indicate that placing the copper strings can increase the pool boiling heat transfer coefficient of FC-72 more than 65% over that for a bare surface for a certain combination of the experimental parameters. However, the boiling heat transfer enhancement varies nonmonotonically with the string size, length and height, reflecting the complex influences of the strings on the bubble motion near the heated surface. An optimal boiling heat transfer enhancement could be procured by a suitable choice of the experimental parameters. The results from the visualization of the boiling flow over the copper plate indicate that installing the copper strings above the plate surface can significantly increase the bubble population in the flow for some cases. Besides, more big bubbles appear in the flow.
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Li, Guo-jhih, and 李國志. "Electrochemical coating of Ag-doped ZnO nanorods on copper plate to study their structure and charatcterization." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/cj88rk.
Full textAbstract:
碩士國立中央大學
機械工程學系
102
The aim of this work was to prepare p-type semiconducting Ag-doped ZnO thin films consisting of nano rods on a Cu-foil (99% in purity) by three-electrode electrochemical method. The reaction was carried out in a 2 mM zinc nitrate solution containing 2 mM hexamine with 2, 6, 10 and 14 μM silver nitrate at 80 ℃ under constant potentials in the range from -0.4 V to -1.0 V against the reference electrode Ag/(AgCl, sat. KCl). Examining through SEM, the coating comprised hexagonal nanorods with their diameters increasing and their distribution denser with more negative potentials applied in the process. After analysis by XRD, the coatings were identified as wurtzite ZnO crystals preferred at (002). This (002) peak shifted to a lower angle in 2θas the films come from the solution containing higher concentration of silver nitrate; it became sharper post annealing in 300 ℃. The XPS of the coating revealed the Ag 3d5/2 spectra characterized by a peak with binding energy at 368.27 eV (i.e., a signal of AgZn-O in ZnO crystals) after deconvolution. Mott-schottky analysis, conducted through EIS, confirmed that p-type thin films consisting of Ag doped ZnO nanorods could be successfully prepared by electrochemical method. The film prepared at -1.0 V in the zinc nitrate containing 6 μM silver nitrate revealed the highest carry concentration (at 1.35×1013 cm-3).
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Hsueh, Cheng-Hung, and 薛正宏. "Enhancement of subcooled FC-72 pool boiling heat transfer by movable copper particles on a horizontal plate." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/71246276448880090920.
Full textAbstract:
碩士國立交通大學
機械工程系所
101
An experiment is carried out here to investigate how subcooled pool boiling heat transfer of liquid FC-72 over a horizontal heated copper plate is affected by placing a large number of copper particles above the plate surface, intending to explore the possible pool boiling heat transfer enhancement by the moving particles. During the experiment, the copper particles are freely placed above the heated plate with a rectangular acryl fence surrounding the plate so that the particles can be moved by the force induced by the boiling flow without been blown away from the heating plate. In the experiment the liquid subcooling ranges from 5℃ to 20℃ and the imposed heat flux is varied from 0.1 to 6 W/cm2 for the diameter of the moving metallic particles fixed at 1.0 and 1.5 mm. Besides, the total particle number placed on the plate ranges from 100 to 1800 and from 200 to 800 respectively for the small and large particles. The measured data are presented in terms of boiling curves and boiling heat transfer coefficients for the heating surface with the presence and absence of the particles. The experimental parameters include the liquid subcooling, imposed heat flux level, and the size and number of the particles. Results obtained from the present study for the subcooled pool boiling of FC-72 show that placing the movable copper particles can significantly increase the pool boiling heat transfer at low liquid subcooling for ∆T_sub≤10℃. For the small copper particles at liquid subcooling ∆T_sub=10℃ and N_p=1600, the enhancement can be up to 200% over that for a bare surface for a certain combination of the experimental parameters. The best enhancement in this study can be as high as 300% for the small copper particles at the liquid subcooling of 5℃ and N_p=1400 &; 1800. Even when more than one layer of particles are placed on the plate, relatively significant boiling heat transfer enhancement can be obtained. However, the boiling heat transfer enhancement varies nonmonotonically with the liquid subcooling, particle size and number, and the heat flux applied, reflecting the complex mutual influences of the movable particles and bubble motion near the heated surface. We also note that at higher liquid subcooling, the copper particles are less effective in augmenting the boiling heat transfer. For the high ∆T_sub of 20℃ the boiling heat transfer is retarded by the copper particles especially when a large number of the particles are placed on the plate. Besides, the wall superheat for the incipient boiling can be substantially reduced by the moving metallic particles in some cases for N_p⁄N_pf ≥1.0 and ∆T_sub≤10℃. However, at high heat flux (wall superheat) placing the particles on the plate can substantially reduce the boiling heat transfer especially for the large particles. The results from the visualization of the boiling flow over the copper plate indicate that placing the movable particles above the plate produce two opposite effects of enhancing and retarding the boiling heat transfer. At high heat flux the retarding effect is strong and boiling heat transfer is impeded by the particles.
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Siao, Kai-Wei, and 蕭凱威. "Exploring acoustic dispersion relations of various thin plate with Chladni figures: Aluminum、Brass、Copper、Stainless steel、Glass、Wood and PMMA." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/qqbt42.
Full textAbstract:
碩士國立交通大學
理學院應用科技學程
102
This thesis propose a method to rapidly and accurately reconstruct the resonant modes and dispersion relationships of thin plates in different materials. In the past, the reconstructions of resonant modes are usually fulfilled by utilizing some approximative method based on numerical iteration to match the experimental resonant frequency spectrum. Besides, the measurements of key elastic coefficients of material, e.g. the Young’s modulus and Poisson ratio, are necessary for the determination of acoustic dispersion relationship. However, not only the numerically iterative process requires tedious calculations which takes lots of time, but the precision of elastic coefficients depend on a large amount of statistics on experimental data. As a consequence, rapid analysis of resonant modes and dispersion relationship are hard to achieve case-by-case by the traditional method. In this work, we analytically develop a theoretical model to calculate the Chladni figures of thin plates. We show the experimental resonant modes can be perfectly reconstructed once the theoretical nodal patterns reveal one-to-one correspondence to the experimental observations. We further demonstrate the dispersion relationships of thin plates in different materials such as aluminum, brass, copper, stainless steel, glass, wood and PMMA can be easily determined by linking the resonant frequencies to the reconstructed wavenumbers.
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Wang, Shu-Lei, and 汪書磊. "Enhancement of FC-72 Flow Boiling Heat Transfer over Heated Plate by Installing Fine Copper Strings, Light Beads and Liquid Superheating." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/52892229164071585638.
Full textAbstract:
博士國立交通大學
機械工程系所
104
An experimental study is carried out here to explore possible enhancement of FC-72 flow boiling heat transfer over a small horizontal heated copper plate by two different active-like passive augmentation methods and by slight inlet liquid superheating. In the first part of the study, movable fine copper strings are installed above the plate. Specifically, parallel strings of uniform size and pitch with their ends only fixed at the plate edges are placed normal to the upstream flow direction. In this part of the experiment, the imposed heat flux is varied from 0.1 to 11 W/cm2, the diameter of strings from 79 to 254 μm, string-heated surface separation distance from 0 to 1.0 mm, and the length of the strings from 10 to 12 mm with the pitch of the strings fixed at 1.0 mm for the FC-72 mass flux maintained at 300 kg/m2s. In the second part of the study, small plastic beads like thick circular rings are mounted additionally on the fine copper strings, in addition. The beads can be irregularly rotated by the shear force from the boiling flow and by the buoyancy of the bubbles. In the test, the chosen reference beads have average outer and inner diameters of 1.45 and 0.65 mm, respectively, and thickness of 1.0 mm. The average weight of a bead is 0.0038 g. Straight parallel strings of the beads at selected pitch and height are placed above the heated plate normal to the incoming upstream flow with their ends fixed at the rig installed near the plate edges. The effects of the relevant parameters on the saturated and subcooled FC-72 flow boiling heat transfer enhancement, including the imposed heat flux, string pitch, number of beads on each wire, and bead-plate separation distance, are examined in detail. In the third and final part of this study, the inlet liquid superheating is controlled by the auxiliary heater which is installed at the upstream diverging portion of the channel. Meanwhile, the pressure in test section is maintained at saturated state. Besides, combination of the installation of copper strings and beads with the inlet liquid superheating to enhance boiling heat transfer is also examined. The experimental data obtained from the first part of the study for the installation of the copper strings show that installing the fine copper strings above the heating surface can enhance the FC-72 flow boiling heat transfer coefficient up to about 30% over that for a bare surface for a well selected set of the experimental parameters. Besides, the string size and length exhibit nonmonotonic effects on enhancing the boiling heat transfer due to complex influences of the strings on the bubble dynamics near the heating surface. Moreover, the presence of the strings is found to increase the size of nucleation bubbles and active bubble nucleation site density but meanwhile impede the bubble departure from the boiling surface. In the second part of the study, the experimental results indicate that the bubble pumping away from the heated surface from the rotating beads can effectively enhance the boiling heat transfer in the saturated and subcooled flows. Besides, the enhancement in the boiling heat transfer is more pronounced when the beads are placed closer to the plate at the medium string pitch. Moreover, there exists an optimal number of beads threaded on each wire. The best enhancement in the saturated boiling heat transfer coefficient in this study can be as high as 55 % for a suitable selection of the experimental parameters. The corresponding best subcooled boiling heat transfer enhancement is 50%. Moreover, the rotating beads can substantially reduce the wall superheat required for incipient boiling in both saturated and subcooled flows. This is particularly beneficial for electronics cooling. Finally, it is noted from third part of the present study that a slight inlet liquid superheating can be very effective in enhancing the FC-72 boiling heat transfer. The significant enhancement is found to mainly result from the increasing the bubble departure size and frequency at increasing liquid superheating. The best boiling heat transfer enhancement can be around 100% for the inlet liquid superheating of 1.2℃ and 1.5℃.
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Vega, Daniel Esteban. "Oil painting on copper: characterization of the copper support and the feasibility of using pigmented wax-resin infills for paint loss reintegration." Master's thesis, 2016. http://hdl.handle.net/10362/20339.
Full textAbstract:
This work resulted in one oral presentation and two publications:
Paper accepted for presentation and publication, Colóquio em Investigações em Conservação do Património, “Arte e Ciência: Investigação sobre a técnica e materiais aplicados na pintura sobre cobre”, Daniel Vega, Isabel Pombo Cardoso and Leslie Carlyle. Faculdade de Belas Artes da Universidade de Lisboa (FBAUL), Lisbon.
Paper accepted for publication, International Symposium Paintings on copper (and other metal plates). Production, degradation and conservation issues, “Investigation and testing to develop an infill formula suitable for oil paintings on copper”, Daniel Vega, Isabel Pombo Cardoso and Leslie Carlyle. Universitat Politècnica de València (UPV), Valencia, Espanha.The present work is divided in two parts. Part 1 concentrates on the study of the manufacture of copper plates used as a support for oil paintings since to date, there has not been a great deal of information available. The research involved comparing the information gathered from historical treatises on metallurgy and recent studies of paintings on copper and copper archaeometallurgy, with results from a set of thorough scientific analyses undertaken on the copper supports of fifteen European paintings (dating from the 17th and 18th centuries). This comparison revealed interesting insights into the metallurgic processes used to produce the copper ingot from native copper, and the subsequent manufacturing processes undertaken to obtain the copper plates. Copper ore purification was a complex and expensive process. Purification included several steps, all of which were rigorously executed as attested by the high level of purity of the copper produced. Scientific analyses undertaken on the copper supports of the fifteen European paintings revealed that the manufacture of the plates from the ingots involved cycles of cold working alternating with annealing. Hammering took place which would have been aimed to form a plate with adequate hardness, while the intermediate stage of annealing returned malleability so that further intense cold work, necessary to achieve a plate without breaking, could be carried out. Part 2 focus on the characterization of two wax-resins formulations used as infill materials for oil paintings: a formula used by Carlyle in the early 1980s (C-PWR) and Gamblin pigmented wax-resin (G-PWR). and, based on the negative impact on copper of the acidic beeswax in both formulations, an exploration to find a new formulation with a neutral acid value was carried out. Preliminary trials and testing focussed on the development of a new wax-resin formulation suitable for infills on oil paintings with a copper substrate. New options for infill materials on copper supports are particularly important as the range of infill materials currently available are not suitable, for a variety of reasons, for use on this type of support. Although ageing tests are still needed, the characterization of the individual materials, and of the new formulation, KTW5-R1, made of Techniwax 9426 microcrystalline wax with Regalrez 1094, showed that this wax resin mixture with an acid number of 0, is likely to be inert in relation to the copper and chemically stable since it is composed of saturated hydrocarbons only.
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Donahue, Chance Thomas. "THERMAL, MAGNETIC, AND MECHANICAL STRESSES AND STRAINS IN COPPER/CYANATE ESTER CYLINDRICAL COILS – EFFECTS OF VARIATIONS IN FIBER VOLUME FRACTION." 2010. http://trace.tennessee.edu/utk_gradthes/699.
Full textAbstract:
Several problems must be solved in the construction, design, and operation of a nuclear fusion reactor. One of the chief problems in the manufacture of high-powered copper/polymer composite magnets is the difficulty to precisely control the fiber volume fraction. In this thesis, the effect of variations in fiber volume fraction on thermal stresses in copper/cyanate ester composite cylinders is investigated. The cylinder is a composite that uses copper wires that run longitudinally in a cyanate ester resin specifically developed by Composite Technology Development, Inc. This composite cylinder design is commonly used in magnets for nuclear fusion reactors. The application of this research is for magnets that use cylindrical coil geometry such as the Mega Amp Spherical Tokamak (MAST) in the UK. However, most stellarator magnet designs use complex geometries including the National Compact Stellarator Experiment (NCSX), and the Quasi-Poloidal Stellarator (QPS). Even though the actual stresses calculated for the cylindrical geometry may not be directly applicable to these projects, the relationship between fiber volume fraction and stresses will be useful for any geometry. The effect of fiber volume fraction on stresses produced by mechanical, thermal and magnetic loads on cylindrical magnet coils is studied using micromechanics with laminate plate theory (LPT) and finite element analysis (FEA).Based on the findings of this research, variations in volume fraction do significantly affect the stress experienced by the composite cylinder. Over a range of volume fractions from 0.3 to 0.5, the LPT results demonstrate that thermally induced stresses vary approximately 30% while stresses due to pressure vary negligibly. The FEA shows that magnetic stresses vary much less at around only 5%. FEA results seem to confirm the LPT model. It was also concluded that the stress in the insulation layers due to all types of loadings is significant and must be considered when using this system in fusion applications.