Recent Progress and Development in Extrusion of Rare Earth Free Mg Alloys: A Review

Mg and its alloys are the lightest structural metals available and are extremely attractive for applications as lightweight components, particularly in the automobile, electronic, and aerospace industries. The global market for wrought Mg alloys has steadily expanded over the past decade. And numerous studies have been carried out to meet this increasing demand of high-performance Mg alloys. However, Mg extrusion alloys have had a very limited usage so far. To overcome existing industrial challenges, one desirable approach is the development of low-cost rare earth(RE) free Mg extrusion alloys with superior mechanical properties. This review will introduce the recent research highlights in the extrusion of Mg alloys, specifi cally focusing on low-cost RE-free Mg alloy. The results from both the literature and our previous study are summarized and critically reviewed. Several aspects of RE-free Mg extrusion alloys are described in detail:(1) novel alloying designs including Mg–Al-, Mg–Zn-, Mg–Ca-, Mg–Sn-, and Mg–Bi-based alloys,(2) advanced extrusion techniques, and(3) extrusion-related severe plastic deformation(SPD) processing. Accordingly, considering the large gap in mechanical properties between the current RE-free Mg alloys and high-performance aluminum alloys, new alloy design, processing route control, and recommendations for future research on RE-free Mg extrusion alloys are also proposed. We hope this review will not only off er insightful information regarding the extrusion of RE-free Mg alloys but also inspire the development of new Mg extrusion technologies.     

Effect of frozen-storage period on quality of American sirloin and mackerel (Scomber japonicus)

Food Science and Biotechnology - This study aimed to study the effect of frozen-storage period on the quality of sirloin and mackerel (Scomber japonicus). The samples were evaluated after being...     

Intravenous Vitamin C administration reduces fatigue in office workers: a double-blind randomized controlled trial

Background  

Studies of the efficacy of vitamin C treatment for fatigue have yielded inconsistent results. One of the reasons for this inconsistency could be the difference in delivery routes. Therefore, we planned a clinical trial with intravenous vitamin C administration.     

Physical and sensory characteristics of fibre-enriched sponge cakes made with Opuntia humifusa

Cheonnyuncho (Opuntia humifusa) has multiple functional properties and is a good source of dietary fibre. The purpose of this study was to investigate the quality characteristics of sponge cakes made with cheonnyuncho powder. The moisture, ash, and dietary fibre levels in the sponge cakes increased linearly with the addition of 0–9 g of cheonnyuncho powder/100 g of wheat flour, and the carbohydrate and calorie contents of the samples decreased. The specific gravity and yield of dough increased with the addition of cheonnyuncho powder. For the crumb colour values, L and a decreased with the addition of cheonnyuncho powder whereas the b and ΔE values increased. In the texture analysis, hardness and gumminess were reduced, but cohesiveness and springiness were increased by the addition of cheonnyuncho powder. When the sensory characteristics were evaluated, the addition of 9 g of cheonnyuncho powder/100 g of wheat flour showed the best sensory properties. Overall, the addition of 9 g of cheonnyuncho powder/100 g of wheat flour improved the physical quality and taste of the sponge cake.     

A facile approach for controlled synthesis of hydrophilic starch‐based nanoparticles from native sago starch

A facile approach for the preparation of hydrophilic starch‐based spherical nanoparticles from native sago (Metroxylon sagu) starch using the drop‐wise solvent exchange method was reported. Starch‐maleate monoester (SM) was initially synthesized from native sago starch and maleic anhydride in an aqueous medium, and SM nanoparticles was subsequently precipitated in absolute ethanol under controlled conditions. The present study was focused mainly on modulating of the solvent and non‐solvent systems to prepare SM nanoparticles of different morphologies. The pH of the solvent system and the nature of surfactants being added into the solvent system could influence the morphology of regenerated SM nanoparticles. SM nanoparticles of discrete and spherical shape were regenerated from a basic SM sample solution, or an acidic sample solution in the presence of an appropriate surfactant. SM nanoparticles with mean diameter of about 250 nm was obtained by precipitation in absolute ethanol in the presence of Brij 35 as the surfactant.     

Predicting the oil cooler fan performance of large-sized diesel engines by changing the outlet and torsion angles

This study analyzed how the outlet and torsion angles of an oil cooler fan in large-sized diesel engines affect the performance of the fan using a numerical analysis method. The discharge flow rate, theoretical power, and efficiency were numerically calculated at the variable outlet and torsion angles. Results showed that the discharge flow rate slightly increased with increased outlet angle, leading to increased theoretical power and efficiency. The outlet-side blade also came closer to a vertical position with smaller torsion angle for higher performance of the fan. To verify the numerical analysis results, an experiment was conducted according to AMCA Standard 210–99 and the results were compared. The performance curve of the experimental and numerical analysis results indicated about 3% error.     

Output feedback tracking control of uncertain robot manipulators via higher-order sliding-mode observer and fuzzy compensator

This paper develops a new method to control uncertain robot manipulators by using only position measurements. The controller is designed based on a combination of a computed torque controller (CTC) with a higher-order sliding-mode observer and a fuzzy compensator. First, three higher-order sliding-mode (SM) observers (second-order SM, third-order SM and third-order SM linear (TOSML) observers) are designed and compared to verify whether the TOSML observer is the best for observing velocity and identifying uncertainty. A combined CTC-TOSML controller was then designed. Although this controller scheme can overcome the drawbacks of conventional CTCs, its tracking performance can still be improved. To enhance capability of the tracking performance, a CTC-TOSML controller plus fuzzy compensator called a CTC-TOSML-Fuzzy controller is proposed. The proposed controller increases the potential of the CTC for real robot applications. Finally, computer simulation results on a PUMA560 robot are discussed to verify the effectiveness of the proposed strategy.     

Texture Evolution in Mg-Zn-Ca Alloy Sheets

Ca was added to Mg-1Zn and Mg-6Zn alloys to modify their texture, and the origin of texture modification by Ca addition has been investigated. It shows that Mg-1Zn-1Ca (ZX11) and Mg-6Zn-1Ca (ZX61) alloy sheets in the as-rolled condition show the textures having a splitting of basal poles toward the rolling direction and a splitting of basal poles toward the transverse direction, respectively. An analysis of the microstructure in the as-rolled condition shows that two different types of twins become active during rolling, double twins for ZX11 and tension twins for ZX61, suggesting that double twinning and tension twinning promote a splitting of basal poles toward the rolling direction (ZX11) and transverse direction (ZX61), respectively. On the other hand, after annealing, both alloy sheets show a weakened texture characterized by a splitting of basal poles toward the transverse direction. During annealing, the growth of tension twin-oriented grains occurs, resulting in the texture having a splitting of basal poles toward the transverse direction in both alloys. These alloys show not only higher yield strength but also better stretch formability than Al 5052 alloy, showing their potential as highly formable Mg sheet alloys.     

Redox-sensitive colorimetric polyaniline nanoprobes synthesized by a solvent-shift process

We have synthesized water-stable polyaniline nanoparticles coated with triarmed polyethylene glycol chains using a solvent-shift method and confirmed their colloidal size and aqueous solubility. Furthermore, we have demonstrated that the polyaniline nanoparticles can be doped with biological dopants to produce distinct color changes allowing the detection of live cancer cells.