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Multiphase microstructure formation and its effect on fracture behavior of medium carbon high silicon high strength steel
No full textThis work investigated the evolution of multiphase microstructure and impact fracture behavior of medium carbon high silicon high strength steel subjected to the austempering treatment at 240, 360, and 400 ℃. The results show that martensite, bainite, and retained austenite (RA) are the main microstructural phases. The austempering treatments at 360 and 400 ℃ caused the formation of carbon-poor ferrite in the matrix, and the transformation of ultrafine bainite into coarse lath bainite and granular bainite, respectively. Thick filmy RA was distributed between bainite laths. The polygonal martensite-austenite islands and blocky RA formed along the grain boundaries. The average carbon concentration in the matrix decreased with the temperature increase, while the impact toughness initially increased and then dropped with temperature. The quasi-cleavage brittle fracture dominated the impact fracture mechanism of the sample austempered at 240 ℃ by forming tearing surfaces and tearing steps. The microcracks disappeared in the RA on the prior austenite grain boundaries. On the other side, the fracture surface of the sample austempered at 360 ℃ exhibited ductile fracture with deep dimples and brittle fracture with cleavage river patterns. The polygonal martensite-austenite islands or blocky RA constrained the microcracks. After austempered at 400 ℃, the brittle fracture was dominant, showing river patterns, and the microcracks propagated through the granular bainite without any resistance
The effect of adhesive type and ply number on the compressive strength retention of CLT at elevated temperatures
No full textThis paper describes novel experiments to identify the reduction in compressive strength of cross-laminated timber (CLT) at elevated temperatures. The adhesive type and number of timber plies was varied between CLT samples to allow an assessment of the CLT ‘system’, rather than timber only. Samples were subjected to steady state and transient heating conditions and their ultimate load bearing capacities were measured. At ambient reference temperatures, a statistically significant difference in ultimate compressive strength was observed between ply numbers but not between adhesive types. For transiently heated samples, capacity was reduced at 100\ua0°C for CLT bonded with polyurethane adhesive type as compared to samples bonded with melamine formaldehyde. The presented results indicate that the composition of CLT can influence the whole system structural response, both at ambient temperature and under fire conditions
Does premenstrual syndrome before pregnancy increase the risk of postpartum depression? Findings from the Australian Longitudinal Study on Women's Health
No full textBackground: Previous literature suggests a positive association between history of premenstrual syndrome (PMS) and development of postpartum depression (PPD); however, limited evidence has come from prospective population-based studies and whether history of depression affects this association is unknown. Methods: This study included 5479 women from the 1973-78 cohort of the Australian Longitudinal Study on Women's Health and estimated the association between pre-pregnancy PMS and PPD. Participants were followed from 22-27 years in 2000 to 37-42 years in 2015. PMS was collected from a 4-category Likert-scale reporting on frequency of PMS in the last 12 months (never, rarely, sometimes, or often) at the survey preceding an index birth. PPD was ascertained from reports of doctor diagnoses for each birth. Relative risks (RRs) and 95% confidence intervals (CIs) were used to estimate the association of interest. The role of history of depression was assessed by testing its interaction with pre-pregnancy PMS. Results: During 15 years’ follow-up, 15.4% of participating women reported PPD; and 55.1% reported PMS (rarely: 17.2%, sometimes: 25.7%, and often: 12.2%). Compared to women who had no PMS before pregnancy, those who rarely had PMS had similar risk of PPD (1.03, 0.82-1.30); whereas those who sometimes or often had PMS had significantly higher risk of PPD (1.31, 1.09-1.57 and 1.51, 1.22-1.87, respectively). History of depression did not affect the association. Limitations: PMS was self-reported. PMS severity was not collected. Conclusions: This large population-based study provides evidence of a dose-response relationship between PMS prior to pregnancy and PPD, independent of history of depression. Evidence to date suggests PMS has the potential to help identify women at increased risk of PPD before pregnancy
Deleuze and Ethology : A Philosophy of Entangled Life
No full textEthology, or, how animals relate to their environments is currently enjoying increased academic attention. A prominent figure in this scholarship is Gilles Deleuze and yet, the significance of his relational metaphysics to ethology has still not been scrutinised. Jason Cullen’s book is the first text to analyse Deleuze’s philosophical ethology and he prioritises the theorist’s examination of how beings relate to each other. For Cullen, Deleuze’s Cinema books are integral to this investigation and he highlights how they expose a key Deleuzian theme: that beings are fundamentally continuous with each other. In light of this continuity then, Cullen reveals that how beings understand each other shapes them and allows them to transform their shared worlds
The feasibility of a personality targeted intervention for addictive overeating: FoodFix
No full textRecent reviews have identified potential treatment targets for addictive overeating. These include: motivational interviewing, development of specific coping strategies for emotional regulation and the use of harm minimisation strategies based on interventions for substance use disorders. However, there is very little experiential evidence. The aim of this study was to determine the feasibility of a personality-targeted motivational interviewing intervention in adults above the healthy-weight range with symptoms of addictive eating, to reduce symptoms of addictive overeating and improve dietary profiles. Individuals with overweight and obesity (BMI >25 kg/m) with addictive eating as defined by the modified Yale Food Addiction Scale (mYFAS) were recruited to a three-session intervention held over 3 months. Sessions were conducted by telehealth and facilitated by dietitians. Fifty-two individuals were randomised to either intervention or control (mean age 43.6 ± 12.2yrs, mean BMI 36.7 ± 6.8 kg/m, 96% female). At three month follow up, there were significant reductions from baseline (BL) for both groups in total YFAS 2.0 symptoms, however, these changes were not significantly different between groups (intervention BL 8.0 ± 2.7; 3-months 6.5 ± 3.8, control BL 8.1 ± 2.5; 3-months 6.9 ± 3.9, p > 0.05). At 3 months the intervention group significantly reduced their energy from non-core foods compared with control (intervention BL 48% energy/day; 3-months 38%, control BL 41% energy/day; 3-months 38%, p < 0.01). The FoodFix intervention provides insight to the development of future management interventions for addictive eating
Carbon accounting of mined landscapes, and deployment of a geochemical treatment system for enhanced weathering at Woodsreef Chrysotile Mine, NSW, Australia
No full textCarbonation of ultramafic mine tailings has the potential to offset greenhouse gas emissions from mining by trapping CO within the crystal structures of Mg-carbonate minerals and hydrotalcite supergroup minerals, which form as weathering products in tailings storage facilities. Here, we present a detailed geochemical and mineralogical assessment of tailings from the Woodsreef Chrysotile Mine, New South Wales, Australia, demonstrating that coupling mineralogical and elemental datasets improves the accuracy of carbon accounting in mined landscapes. Detailed analysis of tailings mineralogy using quantitative X-ray diffraction (XRD) and total carbon analyses reveals that previous assessments of passive mineral carbonation at Woodsreef have been underestimated. Maximum values for the abundance of total carbon (up to 0.4 wt%), as well as the abundances of secondary carbonate minerals (i.e., up to 1.9 wt% hydromagnesite and up to 2.6 wt% pyroaurite, measured with XRD) are observed between approximately 2 cm and 30 cm depth in profiles collected within experimental plots. However, an amorphous Mg-carbonate phase, that cannot be detected using XRD, is also present at comparably high abundances to depths of at least 1 m. This phase is readily observed using scanning electron microscopy, it contributes a measured carbon content of approximately 0.2 wt% at up to 1 m depth, and it has a predominantly atmospheric carbon isotopic signature (FC > 0.80). We find that using only XRD data results in the sequestered CO being underestimated by nearly four times compared to estimates incorporating total carbon measurements, highlighting the important role of amorphous Mg-carbonates in the carbon cycles of mines. Combining XRD and total carbon data, we provide an estimate for passive carbon sequestration by both crystalline and amorphous carbonates in the Woodsreef tailings (11.7 kg CO/m considering the upper 1 m) and suggest that future studies should employ both XRD and total carbon measurements for carbon accounting. The Woodsreef Chrysotile Mine was also the test site for a field-based geochemical treatment system designed to promote mineral carbonation. A solar powered, independently operating geochemical treatment system is designed and deployed to deliver controlled acid (0.08 M HSO) or water leaching treatments, and maintain soil pore saturation within optimal levels (approximately 18–36%) to enhance the weathering rate of mine tailings. While the applied treatment did not accelerate capture and mineralisation of CO from air, it could be coupled to technologies that enhance the supply of CO for mineral carbonation. We apply our new strategy for carbon accounting to this experimental site in order to assess changes in mineralogy and the spatial scale on which carbon accounting must be done to accurately measure carbon sequestered during weathering of ultramafic rock. Our work provides important lessons and context for future trials of accelerated tailings dissolution and mineral carbonation, which will benefit the next stage of development in the scale-up of this technology
Comparison of the structure and properties of hydroxypropylated acid-hydrolysed maize starches with different amylose/amylopectin contents
No full textDually modified regular maize starch (RMS) and high-amylose maize starch (HAMS) were successfully prepared by first acid hydrolysis and subsequently hydroxypropylation. The effects of hydrolysis time (0–24 h) and propylene oxide (PO) content (10–30%) on the structure and physicochemical properties were investigated. The molar substitution (MS) of HAMS samples (up to 0.163) was generally higher than that of RMS samples (up to 0.149), suggesting the higher reactivity of amylose for hydroxypropylation. Besides, PO content had a greater influence on MS whereas the effect of acid hydrolysis time was minor. For both starches, the dual modifications did not cause apparent changes to the granule morphology but reduced gelatinisation temperatures and enthalpy; and a higher PO content led to higher relative crystallinity. These results suggest that hydroxypropylation occurred mainly on the surface of HAMS granules and had little influence on the compact granular structure, whereas this reaction impacted the internal structure of RMS much more. The rheological study shows the introduced hydroxypropyl bulky groups weakened the entanglements between amylose chains or amylopectin chains with long branches. Thus, this work provides insights into the rational design of modified starch products containing different amylose/amylopectin contents with tailored properties
All eyes on visible‐light peroxyoxalate chemiluminescence read‐out systems
No full textChemiluminescence (CL) reactions have been widely employed and explored over the past 50 years because they offer unique light emission upon a defined chemical stimulus. In this Minireview, we focus on peroxyoxalate (PO) compounds because they feature very high quantum yields tuneable over the entire visible spectrum, allowing for visible‐light detection by the naked eye without the necessity for expensive analytical instruments. Although analytical methods have been extensively described, PO‐CL read‐out is a strongly emerging field with ample industrial potential. The state‐of‐the‐art PO‐CL detection read‐out systems for various key analytes is here explored. In particular, structural requirements, recent developments of PO‐CL read‐out probes and current limitations of selected examples are detailed. Furthermore, innovative approaches and synthetic routes to push the boundaries of PO‐CL reactions into biological systems are highlighted. Underpinned by recent contributions, we share perspectives on embedding PO‐CL molecules into polymeric materials, which they consider the next step in designing high performance solid‐phase read‐out systems
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