Auranofin It is common for plants that are deficient in P
It is common for plants that are deficient in P to invest in their roots in order to maximise P uptake from the soil. Here, plants grown in soil amended with OA had a higher root biomass:shoot Auranofin ratio compared with plants in the INORG-P treatment. Additionally, greater allocation of C to roots has been observed when plants have higher rates of colonisation by AMF (Grønlund et al., 2013, Koch and Johnson, 1984, Yano et al., 1996), which, as discussed above, was highest in OA treatments. The plants from all litter treatments also had significantly more P in their roots than plants from the INORG-P treatment. This could be further evidence that these plants were investing strongly in their roots in order to maximise P uptake. However, there is limited research investigating root P contents at low levels of soil plant-available P, with most research on plant P uptake either focusing on older plant roots (e.g. after 60–70 days growth; Tarafdar and Marschner, 1994, Akhtar et al., 2011) or on shoots (e.g. McBeath et al., 2012).
Conclusion While previously the C:P ratio of OA was thought to be an important determinant of plant P uptake from OA (e.g. Takeda et al., 2009) we found that this was not the case. Alternatively, the proportion of P in OA that was orthophosphate gave a reasonable indication of the availability of P in the OA; however, it could not explain differences between the chicken litters. While the CHK-STR had a higher proportion of orthophosphate P and a higher proportion of bicarbonate extractable P compared with CHK-SD, both chicken litters provided plants with similar amounts of P. This could possibly be explained by the higher proportion of phytate in CHK-SD and the higher colonisation of roots in the CHK-SD by AMF compared with CHK-STR. This study provides valuable insights into the interactions between soil chemistry and biology and shows that chicken and pig litters contain P that can be utilised by plants. Further work should investigate OA application to varying soils in longer pot trials and, subsequently, field trials. Additionally, the effect of AM on P uptake from this materials needs to be quantified. This research could lead to more precise usage of OA for P fertilisation and ultimately more sustainable agricultural systems.
Acknowledgements We wish to thank: Dr Sean Mason for his help with soil P analyses, Adjunct Associate Professor Anne McNeill for her help with initial experimental design, Dr Ashlea Doolette for help with P NMR spectroscopy (extraction and analysis); Ms Bo Zheng and Mrs Rebecca Stonor for their help in the laboratory; Roseworthy piggeries for supplying the pig litter and Infield for supplying the chicken litters; Dr Colin Rivers for supplying the soil and both Dr Colin Rivers and Dr Evelina Facelli for providing advice on the soil. This research was funded by the Grains Research and Development Corporation via a Grains Industry Research Scholarship (grant number GRS10686) to JEM and funding from the ARC to TRC (grant number FT120100463).
Introduction With the increasing application of the 304 Stainless Steel (304SS), estimating fatigue lives of structural components becomes more and more important as they have significant influence on the system reliability and safety. As a result, the estimation works for metal-related fatigue are numerous, such as [, , , ]. As indicated in preceding literature, the higher accuracy of the predicted material cyclic mechanical behavior accompanies higher accuracy of fatigue life estimation. Consequently, in order to get an accurate description of metallic fatigue behavior, it is necessary to choose or develop a suitable constitutive model to represent the mechanical properties of materials [, , ]. About studying mechanical behavior subjected to cyclic loading, many experimental studies were conducted [8,9]. Since the structural components always work at a non-zero mean stress condition, this leads to ratcheting effect which is the plastic strain accumulation occurring at such working case. Consequently, along with those experimental studies, many researchers have tried to develop appropriate constitutive models to better predict the ratcheting behavior. The first systematic attempt in this regard may attribute to Ref. , where Prager proposed a linear hardening model capable of capturing the Bauchinger effect. However the model failed to simulate ratcheting strain in the presence of mean stress due to its constant plastic hardening modulus. For this reason, an Armstrong-Frederick (A-F) hardening rule was proposed by adding a nonlinear recall term to Prager's hardening rule . This new term in A-F hardening rule could account for the fading memory effect of the plastic strain path observed in experiments because of the different hardening modulus for the forward and reverse parts in an asymmetrical stress cycle. Then, due to this initial work of Armstrong and Frederick, the idea of describing the evolution of kinematic hardening variables in terms of nonlinear differential equations has been followed in many other studies, for example, Chaboche et al. [, , ]. The total backstress in Chaboche model is an additive decomposed nonlinear A-F kinematic hardening model, in which each of the A-F rules plays a different role in low-mid-high strain ranges. Moreover, this nonlinear kinematic hardening model is rate-independent and able to account for Bauschinger effect. The advantage of this model is that it can be modified to solve for complex behaviors of the materials under various conditions. Besides the Chaboche model, many other evolutions of kinematic hardening models were proposed such as [, , ], the two-surface models of [, , , ], and and so forth.