Drought stress is the main cause of mortality of holm oak (Quercus ilex L.) seedlings in forest plantations. We therefore assessed if drought hardening, applied in the nursery at the end of the growing season, enhanced the drought tolerance and transplanting performance of holm oak seedlings. Seedlings were subjected to three drought hardening intensities (low, moderate and severe) for 2.5 and ...

Strain hardening capability is critical for metallic materials to achieve high ductility during plastic deformation. A majority of nanocrystalline metals, however, have inherently low work hardening capability with few exceptions. Interpretations on work hardening mechanisms in nanocrystalline metals are still controversial due to the lack of in situ experimental evidence. Here we report, by us...

Surface hardening is a high temperature process that creates hard surface alloy layers that improve a metal’s wear resistance. The technique has been used for many years, however, precise control of the surface alloy composition is difficult since accurate control of the gas chemistry is challenging in these processes, which in turn makes it difficult to control the composition of the surface a...

The microstructural evolution during low temperature ageing of two commercial purity alloys (Al1.2Cu-1.2Mg-0.2Mn and Al-1.9Cu-1.6Mg-0.2Mn at.%) was investigated. The initial stage of hardening in these alloys is very rapid, with the alloys nearly doubling in hardness during 20 h ageing at room temperature. The microstructural evolution during this stage of hardening was investigated using diffe...

Based on experimental results, a dislocation material model describing the dynamic strain aging effect at different temperatures is presented. One and two stage loading tests were performed in order to investigate the influence of the loading direction as well as the temperature influence due to the hardening mechanism. Bergström’s theory of work hardening was used as a basis for the model deve...

The present study considers an elastic-plastic contact analysis during loading-unloading of a deformable sphere with a rigid flat using finite element method. The effect of strain hardening on the contact behavior of a nonadhesive frictionless elastic-plastic contact is analyzed using commercial finite element software ANSYS. To study the strain hardening effect different values of tangent modu...

In contrast to previous studies of rapid cold-hardening (RCH), which have investigated the responses of insects maintained under 'summer conditions' (20 degrees to 25 degrees C), this study focuses on the ability of low-temperature acclimated insects to undergo RCH. When the grain aphid Sitobion avenae Fabricus was low-temperature acclimated by rearing for three generations at 10 degrees C, the...

To identify genes involved in stress resistance and heat hardening, replicate lines of Drosophila melanogaster were selected for increased resistance to knockdown by a 39 degrees heat stress. Two selective regimes were used, one with and one without prior hardening. Mean knockdown times were increased from approximately 5 min to > 20 min after 18 generations. Initial realized heritabilities wer...

Stem cold hardening developed to different levels in citrus types tested in controlled environments. Exotherms indicated ice spread was more uniform and rapid in unhardened than in cold-hardened stems. All attempts to inhibit the functioning of citrus leaves resulted in less cold hardening in the stems. Citrus leaves contribute a major portion of cold hardening in the wood.