Interface characterization of Al/Cu 2-ply composites under various loading conditions

The effects of reduction ratio during roll bonding on the microstructural evolution at interface and subsequent mechanical properties of roll-bonded Al/Cu 2-ply sheets were investigated. The interface microstructures for several Al/Cu 2-ply sheets fabricated under different reduction ratios between 30% and 65% were verified by transmission electron microscopy (TEM). Taking the difference of interface microstructure into consideration, 3-point bending and peel tests were performed for obtaining flexural and bonding strengths for Al/Cu 2-ply sheets. The effect of the quantified areas of metallurgical bonding at interfaces on the bonding strength was also discussed. The results show that both the bonding and flexural strengths for Al/Cu 2-ply sheets are reduced by decreasing the reduction ratio during the roll bonding process, which is strongly correlated with the interface microstructure. This was especially verified by observing the interface delamination from the 3-point bent samples.     

The relationship between sensitisation and small punch test behaviour in a high-nitrogen austenitic stainless steel at cryogenic temperatures

Austenitic stainless components used in nuclear fusion reactors must be capable of maintaining reasonable mechanical properties to thermal ageing caused by welding and in‐service. Recently, high‐nitrogen (High‐N) austenitic stainless steels (SS) are receiving increased attention because of their strength advantages, but they have been found to be susceptible to dichromium nitride (Cr₂N) precipitation during thermal exposure at 823–1073 K. The susceptibility to sensitisation at thermal ageing temperature for high‐N austenitic SS is examined using the single‐loop electrochemical potentiokinetic reactivation (EPR) test. High‐N SS were found to be susceptible to sensitisation caused by grain boundary precipitation of Cr₂N, with the degree of sensitisation increasing systematically with ageing time and temperature. In particular, it was found that the precipitates, which effected sensitisation, were changed from carbides (M₂₃C₆) to nitrides (Cr₂N) with increasing ageing time and temperature. The deterioration of mechanical properties associated with thermal ageing in high‐N SS was investigated by a small punch (SP) test using miniature specimens at cryogenic temperatures. Results indicated that the degradation of mechanical properties in this alloy was caused by a decrease of cohesive strength resulting from carbides (Cr₂₃C₆) and nitrides (Cr₂N) precipitated in grain boundaries.     

Effects of Cr interlayer on mechanical and tribological properties of Cr-Al-Si-N nanocomposite coating

Cr-Al-Si-N coatings were deposited on SUS 304 substrate by a hybrid coating system. A Cr interlayer was introduced between Cr-Al-Si-N coating and SUS 304 substrate to improve the coating adherence. The effects of Cr interlayer on the microhardness, adhesion, and tribological behavior of Cr-Al-Si-N coatings were systematically investigated. The results indicate that the microhardness of the Cr-Al-Si-N coatings gradually deceases with increasing thickness of Cr interlayers. The adhesion between Cr-Al-Si-N and SUS 304 substrate is improved by addition of the Cr interlayers. A peak critical load of ~50 N is observed for the coating containing Cr interlayer of 60 nm as compared ~ 20 N for the coating without Cr interlayer. The thicker Cr interlayers result in reduced critical load values. Moreover, the wear resistance of the Cr-Al-Si-N coatings is greatly enhanced by introducing the Cr interlayer with thickness of 60 nm in spite of the decreased microhardness. The friction coefficient of the coating system is also moderately reduced.     

Correlation Between Oxidative Deterioration of Unsaturated Lipid and n-Hexanal during Storage of Brown Rice

n-Hexanal in the headspace over cooked brown rice stored at 5°C and 35°C for 0, 4, 8 and 12 months was determined by a gas chromatographic method using modified direct vapor injection. The off-flavors of stored brown rice were evaluated by n-hexanal and oxidized linoleic acid analysis. The amount of n-hexanal was found to be linearly proportional to the amount of oxidized linoleic acid (correlation coefficient, 0.99). Therefore, the simple and rapid method of vapor injection gas chromatography can be used for determining n-hexanal in the headspace vapor over cooked brown rice. Thus, the off-flavor of the stored brown rice resulting from lipid oxidation can be detected indirectly.     

FEEDING LOW CALCIUM AND ZINC MOLT DIETS SUSTAINS GASTROINTESTINAL FERMENTATION AND LIMITS SALMONELLA ENTERICA SEROVAR ENTERITIDIS COLONIZATION IN LAYING HENS

The objective of these experiments was to determine whether alternative molting diets would minimize Salmonella enterica serovar Entertitidis (S. Enteritidis) colonization in molting hens. Hens were randomly assigned to four treatment groups of 12 hens either full‐fed (nonmolt, NM), molted by feed withdrawal (molt, M), a low calcium (LC containing 800 mg calcium), or LC diet supplemented with 110 mg zinc/ kg of diet (LC‐ZN) in two trials. All hens were challenged orally with 10 ⁵SE on day 4 of experiment. Hen body weight loss was significantly (P < 0.05) increased and ovarian weight was significantly (P < 0.05) decreased in hens fed the LC or LC‐ZN diets compared to NM. Cecal lactic acid concentrations were significantly (P < 0.05) increased in hens fed alternative molting diets. Feed withdrawal molted hens exhibited significantly (P < 0.05) more S. Enteritidis positive and S. Enteritidis crop, cecal, and organ colonization than NM, LC and LC‐ZN hens. Alternative molt diets retain sufficient fermentative activity to limit S. Enteritidis colonization and therefore may have potential to avoid the risk of increasing S. Enteritidis colonization associated with feed withdrawal.     

Entrapment of nutrients during cholesterol removal from cream by crosslinked β-cyclodextrin

This study was designed to elucidate the quantities of nutrients entrapped during cholesterol removal from cream by crosslinked β-cyclodextrin (β-CD, 4–12%, w/v) and to evaluate the amounts of the residual β-CD in cholesterol-removed cream treated by crosslinked β-CD. The content of lactose in the control cream (without the treatment by crosslinked β-CD) was 2.74%, and the amounts of lactose entrapped by crosslinked β-CD ranged from 0.00 to 0.03%. The total amounts of the entrapped short-chain free fatty acid (FFA) and free amino acid (FAA) ranged from 0.04 to 0.12 ppm and from 0.37 to 0.48 μmol/mL, respectively. The amounts of the entrapped water-soluble vitamins (L-ascorbic acid, niacin, thiamine and riboflavin) ranged from 0.01 to 0.05 ppm, from 0.01 to 0.05 ppm, from 0.00 to 0.04 ppm and from 0.02 to 0.05 ppm, respectively. The entrapped amounts of nutrients mentioned above were not remarkably affected by the concentrations of crosslinked β-CD (4–12%, w/v). The very small amounts of residual β-CD in the cholesterol-removed cream were measured (1.86–6.11 ppm). Based on the data obtained from the present study, it is concluded that the amounts of entrapped nutrients were negligible during cholesterol removal from cream by crosslinked β-CD, and the amounts of residual β-CD in cholesterol-removed cream were trace.