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  • 1
    Electronic Resource
    Electronic Resource
    An Analysis on the Forming Characteristics of AA 6063 Aluminium Alloy in Radial-Forward Extrusion Process (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 519-521 (July 2006), p. 925-930 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this paper, the forming process of a central hub by radial-forward extrusion has beenanalyzed by the rigid-plastic finite element method. In this process, the material flows in radialdirection and then deflects 90 degrees into the same direction as that of punch movement. Radialextrusion is used to produce parts that generally feature a central hub with radial protrusions. Designfactors such as mandrel diameter, punch nose radius, deflection corner radius, gap width in annulardirection, and frictional conditions are applied to the present study by simulation. AA 6063 aluminumalloy is selected as a model material for analysis in the present study. The influence of these designfactors on the force requirement during the forming operation and the pressure exerted on the toolingsuch as the punch and mandrel is investigated and the simulation results are quantitativelysummarized in terms of pressure distribution, force-stroke relationships, and maximum forcerequirement, respectively. The main goal of this study is to investigate the effect of those processparameters on the deformation pattern in radial-forward extrusion process, especially the effect ofdeflection corner radius. It has been concluded from the simulation results that a) the frictionalcondition between workpiece and tool does not affect the punch load very much, but the loadsupported by mandrel is more or less significantly influenced by the frictional condition compared tothat of punch, b) the deflection corner radius turns out to be a major process parameter in terms ofmaximum force requirement, and c) a similar trend is found in the punch and mandrel forces duringthe radial extrusion process
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.519-521.925.pdf
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  • 2
    Electronic Resource
    Electronic Resource
    An Analysis on the Forming Load of AA 2024 Aluminium Alloy in Combined and Sequence Operation Process (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 519-521 (July 2006), p. 949-954 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper is concerned with the analysis of the forming load characteristics of aforward-backward can extrusion in both combined and sequence operation. A commerciallyavailable finite element program, which is coded in the rigid-plastic finite element method, has beenemployed to investigate the forming load characteristics. AA 2024 aluminum alloy is selected as amodel material. The analysis in the present study is extended to the selection of press frame capacityfor producing efficiently final product at low cost. The possible extrusion processes to shape aforward-backward can component with different outer diameters are categorized to estimatequantitatively the force requirement for forming forward-backward can part, forming energy, andmaximum pressure exerted on the die-material interfaces, respectively. The categorized processes arecomposed of combined and/or some basic extrusion processes such as sequence operation. Based onthe simulation results about forming load characteristics, the frame capacity of a mechanical press ofcrank-drive type suitable for a selected process could be determined along with securing the loadcapacity and with considering productivity. In addition, it is suggested that different load capacitiesbe selected for different dimensions of a part such as wall thickness in forward direction and etc. It isconcluded quantitatively from the simulation results that the combined operation is superior tosequence operation in terms of relatively low forming load and thus it leads to low cost for formingequipments. However, it is also known from the simulation results that the precise control ofdimensional accuracy is not so easy in combined operation. The results in this paper could be a goodreference for analysis of forming process for complex parts and selection of proper frame capacity ofa mechanical press to achieve low production cost and thus high productivity
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.519-521.949.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    The concentration equation of polymer solution in nonhomogeneous flow field
    Amsterdam : Elsevier
    Journal of Molecular Liquids 59 (1994), S. 115-128 
    Details
    ISSN: 0167-7322
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0167-7322(94)00726-8
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  • 4
    Electronic Resource
    Electronic Resource
    The Effect of Hydroxyapatite on the Remineralization of Dental Fissure Sealant (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 284-286 (Apr. 2005), p. 35-38 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The purpose of this study is to investigate the remineralization of enamel in the human tooth by fissure sealant containing various amount of hydroxyapatite. Prior to remineralization experiments, the necessary requirements of the dental fissure sealant, the curing depth and the curing time, were measured with the content of the hydroxyapatite according to the standard of ISO 6874.Various amount of hydroxyapatite was mixed uniformly using sonicator up to 20 wt% to the fissure sealant. In spite both the curing time and the curing depth were decreased with increasing the content of hydroxyapatite, all samples were satisfied the ISO requirements. Remineralization experimental samples were produced by bonding fissure sealant containing various amount of hydroxyapatite to human tooth enamel using manufacturer’s information. After exposure to the simulated body fluid at 36.5oC for 4 weeks, the bonding strength and the surface morphology were examined using Instron and scanning electronic microscope, respectively. The bonding strength between the fissure sealant and the human teeth was drastically enhanced with the amount of hydroxyapatite. The remineralization zone could be observed along with the boundary of hydroxyapatite and fissure sealant using a scanning electronic microscope
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.284-286.35.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    The Effect of Hydroxyapatite on Bonding Strength in Light Curing Glass Ionomer Dental Cement (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 309-311 (May 2006), p. 881-884 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The mineral phase of bone and teeth is mainly hydroxyapatite. Currently there arenumerous researches being conducted on the effect of the addition of hydroxyapatite to dental materials. Among them, several studied were published stating that the addition of hydroxyapatite to composite resin or glass ionomer cement resulted in an improvement in bonding strength andphysical properties Therefore, this study will investigate the effect that the addition ofhydroxyapatite to light curing glass ionomer cement has on bonding strength. Two different light curing glass ionomer cement products were selected (FujiⅡLC, GC Cor, Japan and Vitremer™ , 3M/ESPE, USA) and hydroxyapatite was mixed into the light curing glass ionomer cement at various concentrations to create hydroxyapatite-light curing glass ionomer cement mixture. In order toconfirm that hydroxyapatite-light curing glass ionomer cement met the basic requirements of dental materials, sensitivity to ambient light, depth of cure, and flexural strength were tested. From the results of the above mentioned tests, the hydroxyapatite-light curing glass ionomer cement with themost superior physical properties for each product (15% HA-Fuji Ⅱ LC, 20% HA-Vitremer™)was bonded to the teeth and then immersed in artificial saliva(36.5℃) for four weeks. Finally the sectioned surface was observed under SEM after measuring the bonding strength. As the hydroxyapatite concentration increased, the depth of cure decreased. However flexural strength increased and there was not much change in the sensitivity to ambient light. Bonding strength, whichwas the main focus of this study, increased with the addition of hydroxyapatie and scanning electron microscope findings show a more cohesive type of fracture in the material with bone like apatite material formation along the tooth-material interface
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.309-311.881.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    A Comparison of the Bone-Like Apatite Formation Potency Between Hydroxyapatite and β-Tricalcium Phosphate in Glass Ionomer Dental Luting Cement (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 309-311 (May 2006), p. 885-890 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Previous studies have shown that hydroxyapatite increases the bonding strength of dental luting cement with human teeth by forming bone-like apatite when it is added to cement. However, due to the low solubility of the hydroxyapatite, its ability to form bone-like apatite decreases in protein-free acellular simulated body fluid with ion concentrations nearly equal to those of the human blood plasma. The purpose of this experiment was to increase the formation of bone-like apatite bymixing hydroxyapatite with β-TCP of high solubility. RelyXTM glass ionomer cement(3M/ESPE, USA) was used as dental luting cement. Film thickness, setting time, and compressive strength was measured for each group of 15% hydroxyapatite, 15% β-TCP, and 15% mixed hydroxyapatite and β-TCP (85:15). Every specimen of each group was immersed in the simulated body fluid for fourweek before measuring bonding strength, and then their sectional surface was observed under SEM. The most noteworthy result was that the group containing β-TCP produced more amount of bone-like apatite compared with the group composed of only hydroxyapatite
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.309-311.885.pdf
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  • 7
    Electronic Resource
    Electronic Resource
    The Effects of Hydroxyapatite on Bonding Strength between Dental Luting Cement and Human Teeth (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 284-286 (Apr. 2005), p. 953-956 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This study aimed to investigate the effects of hydroxyapatite on bonding strength between dental luting cement and human teeth. In the previous study, bonelike forming ability by mixing hydroxyapatite with several bone cements was reported in a protein-free acellular simulated body fluid with ion concentrations nearly equal to those of the human blood plasma. Therefore in this experiment, we assumed that if bonelike apatite layer could form between dental luting cement and human teeth, the bonding strength between the two would improve. In addition, we expected the HAmixed dental luting cement to improve the physical properties. Fuji I glass ionomer and Relyx™ glass ionomer cement were the selected dental luting cements and the film thickness, setting time and compressive strength were measured mixing various concentrations of hydroxyapatite. Glass ionomer cement with the most superior physical properties(Fuji I ; 20% hydroxyapatite, Relyx™ ; 15% hydroxyapatite) was immersed in the simulated body fluid for three weeks and the surface wasobserved under SEM after measuring the bonding strength. As the concentration of HA increased, the film thickness of hydroxyapatite-glass ionomer cement decreased, the setting time increased, and the compressive strength increased. The most noteworthy results were that bonding strength increased, and that bonelike apatite formed on the tooth surface when observed under SEM
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.284-286.953.pdf
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  • 8
    Electronic Resource
    Electronic Resource
    The Effects of Hydroxyapatite on Demineralization Resistance and Bonding Strength in Light-Curing Glass Ionomer Dental Cement (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 396-398 (Oct. 2008), p. 485-488 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: he aim of this study was to evaluate the effect of HA on the demineralization resistance and bonding strength of light-curing glass ionomer dental cement. Tests were conducted using (1) pure Fuji II LC GIC, (2) 15% micro HA-Fuji II LC GIC. Physical properties, demineralization resistance and bonding strength to dentin of teeth were determined. The curing depth in all groups were satisfied the requirement of curing depth of ISO 9917-2:2004(minimum curing depth = 1mm). The depth of cure was reduced with addition of HA, presumably due to the light scattering effect of HA particles. Regarding sensitivity to ambient light, there were no detectable changes of the homogeneity in any groups. Also all groups were satisfied the requirement of the flexural strength of ISO 9917-2:2004(minimum flexural strength = 20MPa). 15% HA-Fuji II LC GIC group was found to present a greater flexural strength than pure Fuji II LC GIC, as the addition of HA promotes a chemical reaction between the HA, the glass powder, and the polyacid. Observing under the CLSM after 4 days of demineralization, there were significant differences in the CLSM and SEM images. Pure Fuji II LC GIC group showed greater enamel demineralization layer than in 15% HA-Fuji II LC GIC group. In SEM analysis, there was greater enamel demineralization in the pure Fuji II LC GIC group, and less demineralized under the influence of HA particles, 15% HA-Fuji II LC GIC group had more even surface particles. 15% HA-Fuji II LC GIC group was found to present a greater bonding strength than pure Fuji II LC GIC group. Observing the fractured surfaces under SEM after the bonding strength test, the cohesive failure rate was found to be in increasing order of pure Fuji II LC GIC, 15% HA-Fuji II LC GIC group. There were bone-like apatite particles observed to be formed in 15% HA-Fuji II LC GIC group
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/58/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.396-398.485.pdf
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  • 9
    Electronic Resource
    Electronic Resource
    The Effect of Nano-Sized β-Tricalcium Phosphate on Remineralization in Glass Ionomer Dental Luting Cement (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 361-363 (Nov. 2007), p. 861-864 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This study aimed to evaluate the anticariogenic and remineralization effects of the glassionomer dental luting cement containing nano-β-TCP in vitro. The β-Tricalcium Phosphate (β-TCP)are the components of dental enamel and bone mineral as biological apatites. In addition, β-TCPcontains a significant amount of calcium and phosphate, which can promote remineralization ofenamel subsurface lesions in animal and human. RelyXTM glass ionomer cement(3M/ESPE, USA)was used as dental luting cement. Film thickness, setting time, and compressive strength wasmeasured for each group of pure glass GIC, 15% nano-β-TCP GIC. Human molars were prepared inbox-shaped cavities that were filled with the GIC with and without the 15% nano-β-TCP were placedin 25ml of pH 5.0 acid buffer for 4 days at 37℃. After 4 days, longitudinal sections (1007m) wereobtained through the center of each restoration. The sections were analyzed using a scanningelectronic microscope (SEM) and confocal laser scanning microscopy (CLSM) to identify the changein the enamel surface. A significant difference in the CLSM images between pure GIC andnano-β-TCP-GIC. CLSM allows the demineralized surface layers of sound enamel to be visualizeddown to approximately 100 μm. The pure GIC specimens had a relatively thick fluorescent layer. Onthe other hand, the fluorescent layer of the nano-β-TCP-GIC specimens were thinner. The SEMimages of micro surfaces demonstrate that nano-β-TCP-GIC is less rough than pure GIC. Therefore,the addition of nano-β-TCP enhanced protection against acid demineralization and promotedremineralization of enamel surface
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.361-363.861.pdf
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  • 10
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    Optimization of single-photon emission computed tomography system for fast verification of spent fuel assembly: a Monte Carlo study (2019)
    Institute of Physics
    Details
    Publication Date: 2019-07-05
    Electronic ISSN: 1748-0221
    Topics: Physics
    Published by Institute of Physics
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