Won-Hyuk Lee, Tae-Wook Na, Kyung-Woo Yi, Seung-Min Yang, Jang-Won Kang, Hyung Giun Kim and Hyung-Ki Park
When a pure titanium component is fabricated in a selective laser melting (SLM) process using titanium powder, the oxygen concentration of the SLM sample increases compared to the…
Abstract
Purpose
When a pure titanium component is fabricated in a selective laser melting (SLM) process using titanium powder, the oxygen concentration of the SLM sample increases compared to the initial powder. The purpose of this paper is to study the reason for increasing oxygen concentration after SLM.
Design/methodology/approach
To understand this phenomenon, the authors analyzed the oxidation behavior during the SLM process thermodynamically.
Findings
Based on the laser parameters used in this study, the temperature of the Ti melt during the SLM process was expected to rise to 2,150°C. Based on the thermodynamic analysis, the equilibrium oxygen partial pressure for oxidation was 2.32 × 10−19 atm at 2,150°C when the dissolved oxygen concentration in the titanium is 0.2 wt.%. However, the oxygen partial pressure inside the SLM chamber was 1 × 10−3 atm, which is much higher than the equilibrium oxygen partial pressure. Therefore, oxidation occurred during the SLM process, and the oxygen concentration of the SLM sample increased compared to the initial powder.
Originality/value
Most studies on fabricating Ti components using additive manufacturing (AM) have been focused on how the changes in the microstructures and mechanical properties depend on the process parameters. However, there are a few studies that analyzed the oxygen concentration change of Ti during the AM process and its causes. In this study, the authors analyzed the oxidation behavior during the SLM process thermodynamically.
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The purpose of this paper is to analyse the effect of the National Pension Scheme (NPS) on the economic well-being of older people in South Korea.
Abstract
Purpose
The purpose of this paper is to analyse the effect of the National Pension Scheme (NPS) on the economic well-being of older people in South Korea.
Design/methodology/approach
It analyses older people aged 60 and over sampled from the third wave of the Korean retirement and income study.
Findings
The analysis shows a gendered effect. The NPS is positively associated with the economic well-being of only older men. This gendered impact is probably attributable to the inherent patriarchal structure of the NPS that is based on the strong male bread-winner model.
Originality/value
The results suggest that promoting the female labour market participation, and also reforming the gender structure of the NPS and South Korean labour market, can be a potential policy option to amend gendered economic well-being in later life.
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María José Andrade-Cuvi, Michelle Guijarro-Fuertes, Analía Concellón, María Gabriela Vernaza and Juan Bravo-Vásquez
The purpose of this paper was to develop a loaf bread enriched with naranjilla (lulo) fruit (shells, seeds and pulp) and determine the technical quality, sensory acceptability and…
Abstract
Purpose
The purpose of this paper was to develop a loaf bread enriched with naranjilla (lulo) fruit (shells, seeds and pulp) and determine the technical quality, sensory acceptability and bioavailability (by in vitro digestion) of antioxidant components.
Design/methodology/approach
Loaf bread was prepared by using a no-time bread-making process. The crumb moisture, specific volume, crust and crumb color, texture profile analysis, analysis of the crumbs' alveoli, sensory evaluation, in vitro simulation of gastrointestinal digestion and antioxidant capacity were determined. Data were analyzed with one-way ANOVA (α = 0.05).
Findings
The specific volume was reduced by 21% (4.62 cm3/g, p < 0.0001), and the hardness was increased by 70% (2.9 N, p < 0.0001). Enrichment of the bread with naranjilla fruit (NF) contributes a yellowish coloration to the bread, which was very well accepted by the consumers and could be considered a natural colorant alternative. Moreover, the sensory evaluation indicated that the analyzed attributes (appearance, color, odor, taste, firmness and overall quality) of the naranjilla bread presented scores higher than 6.5 of 9 points hedonic scale. Naranjilla in the bread formulation had good acceptability by consumers. Naranjilla-enriched bread had an increase in total phenolic (TP)compounds and total carotenoids. In the product without digestion, naranjilla bread increased 1.7 times for TP, 50 times for CT and 1.3 times for TEAC, compared to the control bread (p < 0.0001). The percentage of bioaccessibility for fresh bread without digestion was 39.2 and 53.9% for the control and naranjilla bread, respectively. The addition of NF contributes to a higher TP compounds content and favors its bioavailability.
Practical implications
For bread production, fruits that do not meet the quality standards to be consumed as a natural fruit can be used. In this way, these fruits can contribute as a potential use to reduce agro-industrial waste and as a natural colorant.
Originality/value
Naranjilla is a native fruit from the subtropical Andean regions, which has high ascorbic acid concentrations, making it a fruit rich in antioxidants. Naranjilla-enriched bread contributes with beneficial compounds for the consumer.