Correlations between nanoindentation hardness and macroscopic mechanical properties in DP980 steels

Nanoindentation measurements were obtained on eight commercially-produced DP980 dual-phase steels to quantify the hardness of the individual constituents, ferrite and martensite, in each steel. Each microstructure was also evaluated to determine grain size, martensite volume fraction (MVF), and retained austenite content. Nanoindentation hardnesses and quantitative microstructural measurements were correlated with tensile properties and performance in hole expansion tests to assess the importance of the individual constituent properties. Hole expansion samples were prepared with both sheared edges produced by mechanical punching, and non-deformed edges produced by electric discharge machining (EDM). Average material hardness based on nanoindentation data correlated directly to Vickers hardness measurements, verifying the capability of the nanoindentation technique to produce data consistent with traditional hardness measurements. Yield strength (YS) correlated directly to ferrite hardness indicating that, for a similar MVF and microstructural morphology, the YS is controlled by the strength of the softer matrix phase (ferrite). Hole expansion ratios (HER) on EDM samples decreased with an increase in both martensite and ferrite hardness, indicating that EDM HER values can be enhanced by softening both constituents. Punched-hole HER values decreased with increasing martensite hardness and martensite-to-ferrite hardness ratio, but were independent of ferrite hardness, indicating that softening the martensite while increasing the ferrite hardness could produce a higher HER. (C) 2014 Elsevier B.V. All rights reserved.X1144Nsciescopu

Time for More Support? Stakeholder Engagement for a Long-Term Care Planning Dementia Decision Aid Prototype

Clinical decision aids around long-term care can help support persons living with dementia (PLWD), family care partners, and healthcare providers navigate current and future care decisions. This study describes the iterative development of a long-term care planning dementia decision aid and explores care partner and geriatric providers’ insights regarding its acceptability and usability. Using a convergent parallel mixed methods design, we gathered surveys and completed interviews with 11 care partners and 11 providers. The quantitative and qualitative data were then converged, resulting in four findings: (1) helpfulness of the decision aid in supporting future care planning; (2) versatility of the decision aid in practice; (3) preferences for structure and content of the decision aid; and (4) perceived shortcomings of the decision aid in decision making. Future work should continue to refine the decision aid, pilot implementation, and evaluate potential effects on decision making as part of dementia care

Acute Physicochemical Effects in a Large River-Floodplain System Associated with the Passage of Hurricane Gustav

On 1 September 2008, Hurricane Gustav passed over the Atchafalaya River Basin (ARB) in south-central Louisiana. Anticipating physicochemical shifts due to concentrated precipitation and wind stress generated by this strong category 2 storm, we deployed a continuous recording multiparameter water quality sonde in a southern ARB bayou 3 days prior to storm arrival to document conditions before, during, and after hurricane landfall. Quarter-hourly physicochemical measurements taken over a 2-week period indicated that dissolved oxygen (DO), pH, and specific conductance all reached annual lows immediately following storm passage. The most pronounced poststorm fluctuation involved DO. Daily mean DO concentration dropped to hypoxic level (DO-2 mg/L) within 3 days of landfall, followed by near anoxic conditions within 5 days that resulted in extensive system-wide fish kills. Within 6 weeks, however, DO returned to, and pH was near pre-storm levels. To evaluate the impact of Hurricane Gustav on ARB physicochemistry, we contrasted data on DO, pH, temperature, and specific conductance collected from 16 lower ARB sampling sites over a 54-day interval prior to storm landfall with data collected during a 45-day post-storm period. Results indicated that water quality was highly dissimilar (P\u3c0.0001) between the two periods. © Society of Wetland Scientists 2011