Search results for "engineering.material"
showing 10 items of 2352 documents
Chemical compatibility of bulk alumina in flowing PbLi alloy under magnetic field
2021
Abstract Electrically insulating flow channel inserts (FCI) may be needed in liquid-based breeding blanket concepts to electrically decouple the metal flow from the strong magnetic field in a future fusion reactor. Although the magnetohydrodynamic simulation demonstrates a reduction of the pressure drop when a sandwich-like steel-alumina-steel FCI is employed, the tritium production efficiency in the breeding zone of a breeding blanket is limited to 550 °C due to the steel corrosion. Previous theoretical thermomechanical analyses point out the possible occurrence of induced interfacial stresses between the steel and the ceramic part. Both factors motivate the actual FCI development towards …
Comparison of the environmental assessment of an identical office building with national methods
2019
The IEA EBC Annex 72 focuses on the assessment of the primary energy demand, greenhouse gas emissions and environmental impacts of buildings during production, construction, use (including repair and replacement) and end of life (dismantling), i.e. during the entire life cycle of buildings. In one of its activities, reference buildings (size, materialisation, operational energy demand, etc.) were defined on which the existing national assessment methods are applied using national (if available) databases and (national/regional) approaches. The ?be2226? office building in Lustenau, Austria was selected as one of the reference buildings. TU Graz established a BIM model and quantified the amou…
Inhibition Probing on a Cut-Edge Electrode Machined from a Primer-Coated 2024-T3 Alloy
2013
Conventional corrosion protection of 2024-T3 alloys (AA2024T3) in aeronautic structures combines conversion coating with chromate-inhibited primer protected by a top-coat. In some cases this protection can break down after mechanical damage to the paint systems inducing a risk of localized corrosion if the release of inhibitors trapped in the primer does not reach a critical level. There is a need for developing computational models combining the inhibitor release and transport within and from the coating system andthecorrosioninhibitionprocess,toassistinthedesignofnewmultifunctionalcoatingsystems.Theinfluenceonthecorrosioninhibition of various parameters such inhibitor release rate, defect…
Effect of active application of self-etching ceramic primer on the long-term bond strength of different dental CAD/CAM materials
2021
Made available in DSpace on 2022-04-29T08:36:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Background: The objective of this in vitro study was to evaluate the effect of the active application of self-etching ceramic primer (ME&P) on the bond strength of different dental CAD/CAM materials (Lithium Disilicate ceramic (LD), Leucite ceramic (LE), Zirconia reinforced lithium silicate ceramic (ZLS), and Hybrid ceramic (HC)) with thermocycling aging. Material and Methods: The samples were randomly divided into 16 groups (n = 20). Dual resin cement cylinders were made and light cured for 10 s (1.200 mW/cm2) for the shear bond strength test. 3-way ANOVA revealed that the factors w…
Comparison between different surface treatment methods on shear bond strength of zirconia (in vitro study)
2020
Background To compare the effect of Er:YAG Laser and Air particle abrasion (APA) surface treatments on shear bond strength of Y-TZP to composite resin cuboids in the presence and absence of primer application and salivary contamination. Material and methods Seventy-two cuboidal shaped specimens 7x7x3 were prepared from Y-TZP using CADCAM, cleaned and sintered. Specimens were divided into 2 main groups (n=36) according to surface treatment method; Air particle abrasion (A) and laser (L). Each group was subdivided into 2 subgroups (N = 18) according to surface modification using primer; each subgroup was further divided into 2 subdivisions (N=9) according to the presence of salivary contamina…
Influence of surface preparation on fracture load of resin composite-based repairs
2014
The purpose of the present study is to evaluate the fracture load of composite-based repairs to fractured zirconium oxide (Z) crowns and to ceramic-fused-to-metal (CM) crowns, comparing different mechanical surface preparation methods. A total of 75 crowns were repaired; samples then underwent dynamic loading and thermocycling. Final fracture load values for failure of the repaired crowns were measured and the type of fracture registered. Group I: CM: Surface preparation with a diamond bur + 9.5% Hydrofluoric Acid (HF) etching; Group II): CM: air-particle (Al 2 O 3 ) + 9.5% HF; Group III: CM: Silica coating (SiO 2 ); Group IV): Z: air-particle (Al 2 O 3 ) + HF 9.5%; Group V) Z: Silica coati…
Shear bond strength of ceramic fused to CAD-CAM milled alloys
2018
Background This study evaluated the metal ceramic bond strength of cast Ni-Cr, cast Co-Cr, sintered Co-Cr and milled Co-Cr alloys to ceramic through two application procedures including the ceramic layering technique and ceramic pressed-on technique. Material and Methods Ceramic materials (Ø 8 mm, 1.5 mm thickness) were veneered by either the layering or pressed-on technique to cast Ni-Cr, cast Co-Cr, sintered Co-Cr and hard milled Co-Cr alloy disc (12 × 12 × 0.5 mm) (n=15). All specimens were treated with a thermal cycle process for 500 cycles at the temperature between 5 °C and 55 °C with immerse time of 30 seconds and 5 seconds for specimen transfer. The shear bond strength was determine…
Geochronology and palaeomagnetism of a late Proterozoic island arc terrane from the Red Sea Hills, northeast Sudan
1992
Abstract Size fractions and single grains of zircon, hornblende and biotite have been dated to define the formation age and thermal history of the northern Haya Terrane (NHT), a late Proterozoic island arc terrane of the Red Sea Hills (RSH), northeast Sudan. U Pb and 207 Pb/ 206 Pb zircon data for acidic volcanics and granitoid rocks bracket the time of formation of the NHT between 887 ± 20 and 854 ± 9 Ma. 40 Ar/ 39 Ar hornblende and biotite ages of a gabbro near Suakin suggest passage through the argon closing temperature for hornblende at about 841 ± 4 Ma and 782 ± 6 Ma for biotite. The hornblende age is considered to be representative of the age of magnetic blocking and, hence, the age o…
Modeling of retrograde diffusion zoning in garnet: evidence for slow cooling of granulites from the Highland Complex of Sri Lanka
2003
¶Diffusion modeling of zoning profiles in garnet rims from mafic granulites is used to estimate cooling rates in the Proterozoic basement of Sri Lanka, which represents a small, but important fragment of the Gondwana super-continent. Metamorphic peak temperatures and pressures, estimated with two-pyroxene thermometry and garnet–clinopyroxene–plagioclase–quartz (GADS) barometry, yield 875±20 °C and 9.0±0.1 kbar. These peak metamorphic conditions are slightly higher than results obtained by garnet-biotite Fe–Mg exchange thermometry of 820±20 °C. Reset flat zoning profiles were observed in most garnets. Only narrow garnet rims touching biotite exhibit retrograde zoning in terms of Fe and Mg ex…
Thermodynamics of Proton Binding of Halloysite Nanotubes
2016
In this paper, new information on physical and chemical properties of the widely used nanostructured Halloysite mineral are reported. Given that the Halloysite has a tubular structure formed by a variable number of wrapped layers containing Si-OH and Al-OH groups, their proton binding affinity was measured at different ionic strengths and ionic media by means of potentiometric measurements in heterogeneous phase. One protonation constant for the Si-OH groups and two for the Al-OH groups were determined. The protonation constant values increase with increasing of the ionic strength in all the ionic media. This suggests that the presence of a background electrolyte stabilizes the protonated s…