•Failure at TMAZ/SZ interface in dissimilar FSWed AA7475-AA2198 was studied.•Intergranular cracks emerged immediately after PWHT at 560 °C for 90 min.•Cu-Zn phase segregated at the grain boundary of ...aluminum grains at AA7475-TMAZ.•Composition difference at high-temperature was the driving force for Cu diffusion.•Grain boundary transition (premelting) and wetting had synergy in the failure.
Post-weld heat-treatment (PWHT) of dissimilar AA7475-AA2198 friction stir welds (FSW) at 560 °C followed by water-quenching since cracks were observed at the TMAZ/SZ interface in retreating AA7475 upon quenching. Microstructural studies revealed that composition difference at high-temperature solution-treatment was the driving force for Cu diffusion from advancing AA2198 through grain boundary liquid-metal thin-films, and caused intergranular segregation of a sufficient amount of Cu-Zn phase. Weld residual stresses, weak interfacial strength, grain boundary transition (premelting), and wetting along with thermal expansion coefficient discrepancies were found to be the associated phenomena in intergranular failure.
For the first time, film-forming aromatic acyclic polyimides were obtained as a result of in situ rearrangement or as a result of heat treatment of polycarboxyimidates by the Mumm-Hess mechanism. ...Intermediate polycarboxyimidates were prepared using the acid-catalyzed reaction of dicarboxylic acids and dinitriles in ionic liquids. The probable mechanism and the corresponding kinetic parameters of thermooxidative decomposition of acyclic polyimides were determined using NetzschThermokinetics 3 – multidimensional nonlinear regression software.
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•For the first time APIs were obtained in the super-acidic ionic liquid 1-Bu-3-MeImAl2Cl7.•Intermediate PCI can rearrange in situ or by thermolysis.•The thermokinetic parameters of API destruction have been established.•Thermal degradation of API begins with the release of water.•API can be well processed from amide solutions or melts.
This study aimed to investigate the suitability of lentil protein and emulsions thereof for the formulation of a milk substitute. The effect of high-pressure homogenisation and heat treatments on ...functional and physico-chemical properties of lentil protein solutions (3.3% w/w) and the emulsions, containing fat contents similar to commercial cow’s milk, was studied. Dynamic high-pressure treatments of 180 and 900 bar greatly affected physical and structural properties of the lentil proteins: the particle size was reduced by 100-fold to 129.00 nm for samples homogenised at 900 bar, leading to an almost complete solubilisation. Surface properties of lentil protein changed, as shown in an increase of hydrophobicity and decrease of free sulfhydryl groups, while changes in secondary structure and aggregation did not develop. Little impact was observed of the heat-treatment at 65 or 85 °C, however, colour changed from a faint pink hue to be more white in appearance. The obtained emulsions exhibited good colloidal stability at both homogenisation pressures, while overall product quality was best when treated at 900 bar. Sensory analyses showed the formulated lentil-based milk substitute had textural and organoleptic profiles comparable to commercial plant-based milk substitutes, including soya-based products. Lentil protein isolates showed great potential to be used formulating milk substitutes with a high-protein content, similar to cow’s milk.
Bovine milk processing influences the structure of the curd formed during gastric digestion, which may alter gastric protein hydrolysis and impact amino acid (AA) release into the small intestine.
...This study aimed to determine the influence of heat treatment and homogenization on the gastric protein digestion and AA emptying of bovine milk.
Nine-wk-old pigs (n = 144) consumed either raw, pasteurized nonhomogenized (PNH), pasteurized homogenized (PH), or ultra-high-temperature homogenized (UHT) bovine milk for 10 d. On day 11, fasted pigs received the milk treatment (500 mL) before gastric contents were collected at 0, 20, 60, 120, 180, and 300 min postprandially. The apparent degree of gastric protein hydrolysis (based on the release of free amino groups), apparent gastric disappearance of individual proteins based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) gel band intensity, and the gastric emptying of digested protein and AA were determined.
During the first 60 min, the rate of apparent gastric protein hydrolysis was fastest in pigs fed UHT milk (0.29%/min compared with on average 0.07%/min in pigs fed raw, PNH, and PH milk). Differences in the apparent degree of gastric protein hydrolysis and emptying were reflected in the rate of digested protein entering the small intestine. The AA gastric emptying half-time was generally shorter in pigs fed PH and UHT milk than in pigs fed raw and PNH milk. For example, the gastric release of total essential AA was >2-fold faster (P < 0.01) in pigs fed PH or UHT milk than that in pigs fed raw or PNH milk (i.e., homogenized compared with nonhomogenized milk).
Heat treatment and homogenization increased the apparent gastric degree of protein hydrolysis and the release of digested protein into the small intestine. However, the rate of AA entering the small intestine was mainly increased by homogenization.
The microstructure and mechanical properties of 2195 Al–Li alloy manufactured by additive friction stir deposition (AFSD) were thoroughly investigated before and after various post-heat treatments. ...The 4-layer built sample is characterized by the distinct layer-dependent microstructure, i.e., the grain size, texture, and precipitate, and resultant heterogenous mechanical properties, owing to the layer-dependent thermal histories of each layer. Post-heat treatments can significantly improve the mechanical strength and reduce the layer-dependent mechanical properties, via introducing the nanosized T1-phase. The AFSD Al–Li alloy after solution treatment and artificial aging achieved the max YS of 491.1 MPa and max UTS of 505.0 MPa. However, the ductility of the alloy is concomitantly reduced by the presence of precipitate free zones (PFZ) along grain boundaries after post-heat treatments. For the bottom layers, EL of AFSD-A and AFSD-ST-A samples are decreased by 65.3% and 76.2%, respectively, compared to AFSD.
Objectives
To determine whether the surface treatment of zirconia affects biofilm formation in an in vitro three‐species biofilm model and in situ.
Material and methods
Zirconia surfaces considered ...for the transmucosal portion of a zirconia implant were compared with polished pure titanium grade 4 (Tp). Disks 13 mm in diameter of either polished (Zp), polished and heat‐treated (Zpt), machined (Zm), machined and heat‐treated (Zmt) and sandblasted, etched and heat‐treated (Z14) zirconia were fabricated. Surface roughness and wettability of specimens was measured. Biofilm formation was evaluated by safranin staining and scanning electron microscopy (SEM) using a three‐species model, and intraorally with 16 volunteers carrying oral splints in two independent experiments. Relative biofilm formation was compared with Kruskal–Wallis followed by Bonferroni post hoc test (α = 0.05).
Results
In vitro biofilm formation with optical density values on Zp (0.14 ± 0.01), Zpt (0.14 ± 0.02), Zm (0.13 ± 0.01) and Zmt (0.13 ± 0.01) was significantly lower than on Tp (0.21 ± 0.05) and Z14 (0.20 ± 0.04) (p < .05). In situ biofilm formation was significantly higher on Z14 (0.56 ± 0.45) (p < .05), while no significant differences in optical density were observed among Zp (0.25 ± 0.20), Zm (0.36 ± 0.34) and Tp (0.28 ± 0.22). SEM analysis supported quantitative findings.
Conclusions
In the in vitro, three‐species biofilm model differences in material and surface roughness affected biofilm formation. In situ biofilm formation was mainly affected by the surface roughness of the specimens. Polishing of zirconia is recommended to reduce biofilm formation, while heat treatment has no significant effect.
Abstract
A study was carried out to investigate the effect of an oil heat treatment process on the physical and mechanical properties of the 10 and 15-year-old cultivated
Tectona grandis
wood. All ...the wood specimens typically possess the sapwood having lighter colour than the dark colour heartwood, and turning these woods into products at this stage results in uneven colour due to the combination of sapwood and heartwood. The situation was to decrease the aesthetic value of the product. Therefore, the oil heat-treatment process enhanced and improved the physical and mechanical properties of the wood in the long run. In designing this study, factors such as the wood height, wood portion, temperatures applied, and treatment duration are considered. The sapwood and heartwood of wood underwent the hot oil treatment process using oil palm crude oil at 160°C, 200°C, and 240°C for 2 hours., respectively. The physical and mechanical properties of the treated wood were determined following the ASTM standards. The relationship between the physical and mechanical properties and treatment variables was determined using the correlation analysis. The results showed that temp. is one of the main variables affecting the properties of treated wood.
Intercritical treatments within the dual-phase (α+γ) region were applied on HSLA pipeline steels, for acquiring a low yield ratio (YR) well balanced with desirable strength. Intercritical cooling ...treatment (ICT), step cooling treatment (SCT) as well as direct cooling treatment (DCT) after full austenization were designed to obtain an optima multiphase microstructure. Effects of cooling rate in DCT routine and intercritical temperatures in ICT and SCT routines on microstructural evolution and corresponding mechanical properties were also investigated. Especially, the SCT treatment applied with an intercritical temperature of 750 °C produces a microstructure composited of “soft” coarse polygonal ferrite, and “hard” acicular bainite and lath martensite containing large amounts of dislocation tangles or networks generated by deformation. Such multiple phase constituents guarantee the high strength and remarkable ductility on deformation, meanwhile cleavages propagation is hindered by the high-angle boundaries of bainite and martensite sheaves, which leads to the lowest YR ~0.61 combined with highest tensile strength among all. In addition, by using the Swift equation to elucidate the relationship between the phase component and yield ratio, it is found that simply increasing the fraction of low-temperature transformed phases, like high-strength acicular bainite and lathed martensite, or the percentage of soft polygonal ferrite for good ductility, can hardly solve the problem how to achieve ultralow-YR pipeline steels balanced with enhanced strength. The present result proves that, through utilizing the proposed SCT heat treatment on pipeline steels, an ultralow yield ratio ~0.61 achieved is synchronized with a desirable strength, which efficiently overcomes the trade-off limit between the strength and yield ratio when applying conventional heat-treatment routines. The fact indicates that, rationally adjusting the content of multi-phase microstructure through optimizing the intercritical treatment conditions, can enable us of realizing the synchronous improvement of the YR and strength in HSLA pipeline steels for real engineering.
•Annealed + aged Al0.25CoCrFeNi alloy shows high hydrogen embrittlement resistance.•High dislocation density and aggregated second phase help the initiation of HE crack.•Decreasing dislocation ...density and aging precipitation improve HE resistance of alloy.
In this study, the influences of annealing and aging treatments on the hydrogen embrittlement (HE) behavior of the cryo-rolled Al0.25CoCrFeNi high entropy alloy (HEA) were investigated through tensile tests and electrochemical hydrogen charging experiments. The results found that the aged sample showed high strength but was more susceptible to HE. A trade-off between the strength and HE resistance was achieved in the annealed + aged sample. Electron backscatter diffraction analysis and fracture characteristics were performed to clarify the HE mechanism. The high dislocation density and aggregated second phase along the grain boundaries in the aged sample were the important factors to help the initiation of HE crack, and then increasing the HE susceptibility. The annealed + aged sample with low dislocation density and aging precipitation reduced the risk of hydrogen-induced cracking and resulting in the excellent HE resistance. This work offered the method to obtain a comprehensive improvement in the strength and HE resistance of this alloy.
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