Statistical aspects of fatigue crack growth life of base metal,weld metal and heat affected zone in FSWed 7075-T651 aluminum alloy

The statistical aspects of fatigue crack growth life of base metal (BM), weld metal (WM) and heat affected zone (HAZ) in friction stir welded (FSWed) 7075-T651 aluminum alloy has been studied by Weibull statistical analysis. The fatigue crack growth tests were performed at room temperature on ASTM standard CT specimens under three different constant stress intensity factor range controls. The main objective of this paper is to investigate the effects of statistical aspects of fatigue crack growth life on stress intensity factor ranges and material properties, namely BM, WM and HAZ specimens. In this work, the Weibull distribution was employed to estimate the statistical aspects of fatigue crack growth life. The shape parameter of Weibull distribution for fatigue crack growth life was significantly affected by material properties and the stress intensity factor range. The scale parameter of WM specimen exhibited the lowest value at all stress intensity factor ranges.     

Toward increasing erucic acid content in oilseed rape (<Emphasis Type="Italic">Brassica napus</Emphasis> L.) through the combination with genes for high oleic acid

Erucic acid (22∶1) is a valuable renewable resource that has several applications in the oleochemical industry. High 22∶1 rapeseed (HEAR) contains around 50% 22∶1. For its technical use it is desirable to increase the 22∶1 content and to decrease the eicosenoic acid (20∶1), PUFA (18∶2+18∶3), and saturated FA (16∶0+18∶0) contents. In the present experiment, HEAR was crossed to high oleic acid rapeseed (ca. 85% 18∶1) with the hypothesis that a combination of the involved genes should lead to a reduced 18∶1 desaturation and to an increased availability of oleoyl-CoA, which should result in enhanced 22∶1 synthesis. A NIR spectroscopic calibration for 22∶1 was developed for single seeds, and the calibration was used to select, in a nondestructive manner, F₂ seeds high in 22∶1. Selected F₂ seeds were sown in the field and F₃ seeds were harvested. The results of the FA analysis showed recombinant genotypes with increased total monounsaturated FA (22∶1+20∶1+18∶1) of up to 89% and decreased PUFA (<8%) and saturated FA content (<3.5%). There was no significant difference in 22∶1 content, but a 3 to 5% increase in 20∶1 content was observed in comparison to the HEAR parental cv. Maplus. Results were confirmed following cultivation of selected plant material a second year in the field. The present study revealed that there are other biochemical limitations than the pool of available oleoyl-CoA that restrict FA elongation to 22∶1 in rapeseed. The generated high 22∶1 plant material with an increased 18∶1 content may be useful in further studies to identify these limitations.     

Release behavior of 1‐methylcylopropene coated paper‐based shellac solution in response to stepwise humidity changes to develop novel functional packaging for fruit

1‐Methylcyclopropene (1‐MCP) has been shown to be a suitable inhibitor of ethylene production in fruit and vegetables during preservation and distribution. In this study, a 1‐MCP controlled‐release system on coated paper was produced using shellac as the coating material. The effect of humidity and temperature on the release of 1‐MCP from the coated paper was investigated using a dynamic sorption system (DVS) with stepwise humidity changes (initial 20% relative humidity (RH) for 2 h, then increased to 40%, 50%, 60%, and 80% RH for 2 h, respectively). The release rate kinetic data were simulated using an Avrami equation with a mechanism release number n of 1.26. The results showed that the dynamic release of 1‐MCP from the coated paper was mainly affected by humidity, for which the release rate constant could be correlated with moisture concentration in humid air. The highest humidity condition (80% RH) resulted in the highest apparent activation energy of 46.8 kJ/mol. The effect of 1‐MCP coated paper on apple storage was evaluated by measuring the ethylene production rate, flesh firmness, and titratable acidity (TA) of apple. Ethylene production rates of apple were significantly affected with 1‐MCP coated paper. The values were 0.22 nL/g FW/h at 50 mg of 1‐MCP powder and 44.7 nL/g FW/h at 0 mg of 1‐MCP powder after 15 days at 4°C and 15 days at 20°C. The other properties of apple such as flesh firmness and TA also indicated that 1‐MCP coated paper could delay fruit softening during storage time. Based on these results, the release of 1‐MCP could be controlled by coating paper with shellac solution and promising to produce functional packaging for fruit.