Uncertainty in climate change impacts on basin-scale freshwater resources – preface to the special issue: the QUEST-GSI methodology and synthesis of results

This paper presents a preface to this Special Issue on the results of the QUEST-GSI (Global Scale Impacts) project on climate change impacts on catchment-scale water resources. A detailed description of the unified methodology, subsequently used in all studies in this issue, is provided. The project method involved running simulations of catchment-scale hydrology using a unified set of past and future climate scenarios, to enable a consistent analysis of the climate impacts around the globe. These scenarios include "policy-relevant" prescribed warming scenarios. This is followed by a synthesis of the key findings. Overall, the studies indicate that in most basins the models project substantial changes to river flow, beyond that observed in the historical record, but that in many cases there is considerable uncertainty in the magnitude and sign of the projected changes. The implications of this for adaptation activities are discussed

Characterizing Granular Mixing Homogeneity at Various Dimensionless Mixing Lengths in a Double Screw Mixer

Granular mixing processes are commonly used to increase product homogeneity in many industrial applications involving pharmaceuticals, food processing, and energy conversion. Determining the appropriate granular mixing length is necessary to avoid over/under mixing and unnecessary power consumption. The goal of this study is to experimentally characterize the granular mixing process and determine, under various operating conditions, the needed mixing length to achieve adequate mixing in a laboratory-scale double screw mixer. Nine different combinations of screw rotation speeds and dimensionless screw pitches are used to investigate the rate of mixing at dimensionless mixing lengths of L/D = 2, 5, and 10. Composition and statistical analysis methods are employed to assess mixing effectiveness, and it is determined that the dimensionless mixing length is the most influential parameter in terms increasing granular homogeneity. For all the conditions tested, the granular mixture approaches an acceptable level of mixing for all testing conditions when the dimensionless mixing length is L/D = 10. However, the segregation rate throughout the screw mixer is vastly different for various combinations of screw rotation speed and dimensionless screw pitch, and is partly attributed to the influence of entrance effects caused by the material injection process

The Co-Occurrence of Polypharmacy and Unmet Needs for Social Care in Older People: A Systematic Review

\ua9 2024 Laurie E. Davies et al.Polypharmacy is common in older people who often live with disability and dependency. The number of older people living with unmet needs for social care is also believed to be rising. Polypharmacy is simple to operationalise, whilst unmet needs are not routinely identified but are known to adversely affect health and well-being. Therefore, this systematic review aimed to investigate whether polypharmacy is a marker of unmet needs for social care in older people. Sixteen databases were searched from inception to January 2021. Studies were included if they reported quantitative data for polypharmacy ("multiple medicines") in relation to unmet needs for social care ("relative or absolute") in older people ("study criteria aged ≥55 years or mean age ≥55 in the sample as a whole or stratified data for the ≥55-year age group") and were from a high-income country (defined by the World Bank). Quality was assessed using the National Institute for Health tool for observational studies. Four studies were identified from 2,549 citations, and overall, the quality of evidence was low. Some older people using multiple medications had their social care needs met, whilst others did not. However, there is a clear rationale as to why polypharmacy may be linked to unmet social care needs. Given the limited studies identified in this review, future research should explore this further. The type of unmet need measure may be important to understand the nature of the relationship between the use of multiple medications and unmet social care needs

Experimental Validation of a Numerical Phase Change Model for Microchannel Slug Flow Boiling

Thermal management of high-power electronic devices continues to be a critical challenge. Flow boiling in microchannel heat sinks has been demonstrated to be an effective method for removing high heat fluxes from these devices owing to utilization of the latent heat of the fluid and the large surface area enhancement for heat exchange. However, microchannel flow boiling technologies have yet to be broadly implemented due to a lack of experimentally validated prediction and design tools. The goal of this study is to use high-fidelity experimental data to validate a previously developed numerical phase change model, to help enable physics-based prediction of flow boiling heat transfer characteristics and reduce the reliance on empirical-based correlations. A novel experimental facility was used to generate archetypal microchannel slug flow boiling and capture high-speed flow visualizations for a range of heat fluxes and flow rates. Image processing of the flow visualizations was performed to extract time-resolved hydrodynamic and heat transfer parameters, such as vapor bubble length and liquid film thickness. The experimental boundary, initial, and operating conditions are input into the numerical model, implemented via a user-defined function in a commercial finite-volume software package, to predict the vapor bubble growth by phase change and the liquid film thickness. A direct comparison of the model prediction and experimental results is performed and good agreement is obtained

Adverse Outcomes of Polypharmacy in Older People : Systematic Review of Reviews

Objective Polypharmacy is widespread among older people, but the adverse outcomes associated with it are unclear. We aim to synthesize current evidence on the adverse health, social, medicines management, and health care utilization outcomes of polypharmacy in older people. Design A systematic review, of systematic reviews and meta-analyses of observational studies, was conducted. Eleven bibliographic databases were searched from 1990 to February 2018. Quality was assessed using AMSTAR (A Measurement Tool to Assess Systematic Reviews). Setting and participants Older people in any health care setting, residential setting, or country. Results Twenty-six reviews reporting on 230 unique studies were included. Almost all reviews operationalized polypharmacy as medication count, and few examined medication classes or disease states within this. Evidence for an association between polypharmacy and many adverse outcomes, including adverse drug events and disability, was conflicting. The most consistent evidence was found for hospitalization and inappropriate prescribing. No research had explored polypharmacy in the very old (aged ≥85 years), or examined the potential social consequences associated with medication use, such as loneliness and isolation. Conclusions and implications The literature examining the adverse outcomes of polypharmacy in older people is complex, extensive, and conflicting. Until polypharmacy is operationalized in a more clinically relevant manner, the adverse outcomes associated with it will not be fully understood. Future studies should work toward this approach in the face of rising multimorbidity and population aging

Transient Flow Boiling and Maldistribution Characteristics in Heated Parallel Channels Induced by Flow Regime Oscillations

Flow boiling provides an effective means of heat removal but can suffer from thermal and hydrodynamic transients that compromise heat transfer performance and trigger device failure. In this study, the transient flow boiling characteristics in two thermally isolated, hydrodynamically coupled parallel microchannels are investigated experimentally. High-speed flow visualization is synchronized to high-frequency heat flux, wall temperature, pressure drop, and mass flux measurements to provide time-resolved characterization. Two constant and two transient heating conditions are presented. For a constant heat flux of 63 kW/m 2 into each channel, boiling occurs continuously in both channels and the parallel channel instability is observed to occur at 15 Hz. Time-periodic oscillations in the pressure drop and average mass flux are observed, but corresponding oscillations in the wall temperatures are virtually nonexistent at this condition. At a slightly lower constant heat flux of 60 kW/m 2 , boiling remains continuous in one of the channels, but the other channel experiences time-periodic flow regime oscillations between single-phase and two-phase flow. At this condition, extreme time-periodic wall temperature oscillations are observed in both channels with a long period (~7 s) due to oscillations in the severity of the flow maldistribution. For the transient heating conditions, square-wave heating profiles oscillating between different heat flux levels are applied to the channels. Because of their relatively high frequency, the heating transients are attenuated by the microchannel walls, resulting in effectively constant heating conditions and flow boiling characteristics like that of the aforementioned constant heating conditions. This study illustrates the susceptibility of parallel two-phase heat sinks to flow maldistribution, particularly when undergoing transient flow regime oscillations.This is a manuscript of the article Published as Kingston, Todd A., Brian D. Olson, Justin A. Weibel, and Suresh V. Garimella. "Transient flow boiling and maldistribution characteristics in heated parallel channels induced by flow regime oscillations." IEEE Transactions on Components, Packaging and Manufacturing Technology 11, no. 10 (2021): 1615-1624. doi: https://doi.org/10.1109/TCPMT.2021.3106226. Copyright 2021 Institute of Electrical and Electronics Engineers (IEEE). Posted with Permission

Thermal gradient strategy to improve seeding for high rate zero excess lithium metal batteries

Zero excess lithium metal batteries (LMBs) have traditionally suffered from short cycle life due to nonuniform processes that result in parasitic side reactions and a subsequent loss of lithium inventory and electrolyte. The experiments herein demonstrate that zero excess LMB cells cycled with a low thermal average and thermal gradient outperform cells cycled under isothermal conditions during early cycles. Specifically, a low thermal average of ∼6.4°C and thermal gradient of 4C) and mismatched charge/discharge rates. Optimal cycling behavior was observed with 2C charging (30 min) and 3C discharging (20 min). These advantages were translated to the system relevant form factor-pouch cell (20X capacity). Based on the performance enhancement observed with extended application of a thermal gradient, we demonstrate the use of the environment as a formation strategy, to perpetuate improved plating in stripping over the cycle life of zero excess LMBs operating in ambient conditions.This article is published as Raj, Abhi, Robert W. Atkinson III, Todd A. Kingston, Rachel Carter, and Corey T. Love. "Thermal gradient strategy to improve seeding for high rate zero excess lithium metal batteries." Frontiers in Energy Research 12 (2024): 1327955. doi: https://doi.org/10.3389/fenrg.2024.1327955. © 2024 Raj, Atkinson, Kingston, Carter and Love. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY)

Microscopic Particle Image Velocimetry Analysis of Multiphase Flow in a Porous Media Micromodel

Pore-scale oil displacement behavior was investigated in a porous media micromodel using microscopic particle image velocimetry (μPIV). Porous media micromodels consisting of an ordered square array of cylindrical pillars with 50 and 70% porosities were fabricated with photolithography. The oil displacement was performed with the injection of water at flow rates of 37.5, 75, and 150 μL/h. These flow rates correspond to Reynolds number of 1.1 × 10–2, 2.2 × 10–2, and 4.4 × 10–2, respectively in the 50% porous channel, and 1.84 × 10–3, 3.69 × 10–3, and 7.38 × 10–3, respectively in the 70% porous channel. The capillary numbers for these flow rates are 2.18 × 10–5, 4.36 × 10–5, and 8.72 × 10–5, respectively in the 50% porous channel, and 1.56 × 10–5, 3.12 × 10–5, and 6.23 × 10–5, respectively in the 70% porous channel. The micromodel is initially saturated with oil, with the invading water phase following the path of least resistance as it displaces the oil. The μPIV data were used to construct probability density functions (PDFs) which show an initial, nonzero, peak in transverse velocity as the water enters the micromodel. The PDFs broaden with time, indicating that the water is spreading, before retracting to a peak velocity of 0 mm/s, indicating that the water displacement has achieved equilibrium. We developed a model based on conservation of mass to describe the efficiency of the displacement process. All flow conditions demonstrate peak displacement efficiency when the amount of oil phase displacement is ∼9 pore volumes in 50% porous channel and ∼4 pore volumes in 70% porous channel.This article is published as Miah, Md Abdul Karim, Kawkab Ahasan, Todd A. Kingston, Michael G. Olsen, and Jaime J. Juárez. "Microscopic Particle Image Velocimetry Analysis of Multiphase Flow in a Porous Media Micromodel." ACS Omega (2024). doi: https://doi.org/10.1021/acsomega.4c04680. Copyright © 2024 The Authors. This publication is licensed under CC-BY-NC-ND 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/)

Thermal gradient strategy to improve seeding for high rate zero excess lithium metal batteries

Zero excess lithium metal batteries (LMBs) have traditionally suffered from short cycle life due to nonuniform processes that result in parasitic side reactions and a subsequent loss of lithium inventory and electrolyte. The experiments herein demonstrate that zero excess LMB cells cycled with a low thermal average and thermal gradient outperform cells cycled under isothermal conditions during early cycles. Specifically, a low thermal average of ∼6.4°C and thermal gradient of <1°C across the cell is shown to increase the overpotential for lithium deposition at the anode current collector, likely resulting in smaller and higher density nucleates, providing film like morphologies observed with microscopy. Improved performance from this approach is demonstrated at high cycling rates (>4C) and mismatched charge/discharge rates. Optimal cycling behavior was observed with 2C charging (30 min) and 3C discharging (20 min). These advantages were translated to the system relevant form factor-pouch cell (20X capacity). Based on the performance enhancement observed with extended application of a thermal gradient, we demonstrate the use of the environment as a formation strategy, to perpetuate improved plating in stripping over the cycle life of zero excess LMBs operating in ambient conditions