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Despite the widespread use of the superelastic nitinol wires in various industries, there exists a critical understanding gap regarding the relationship between wire diameter and fatigue behavior. This study aims at bridging this gap through a systematic, experimental investigation. During the wire drawing process, which is commonly employed to produce smaller wires, microstructural damage is introduced to the material. Microstructural inhomogeneities affect the phase transformations and also serve as fatigue crack initiation sites. Through microstructural analysis and low-cycle fatigue tests on nitinol wires of varying sizes, we confirmed that wire size significantly influences superelastic properties and fatigue response. Smaller wires exhibit better functional performance but are more vulnerable to surface defects, while larger wires experience greater microstructural damage. These findings highlight the need for careful control of wire size and microstructure in designing nitinolbased devices. 

This articles intent is to convey that a weighted nonconformal nonlocal average is computationally tractable and has potential to predict a more accurate statistical spread in FIP values than other mesh independent nonlocal approaches considered. 

In engineering, thermal, and mechanical field quantities (i.e., stress, deformation, temperature) are calculated at every point in a complex structure to ensure quality performance before costly manufacturing. These calculations are often performed using finite element analysis. However, for determination of some performance metrics (usually relating to fracture), a local measure at every point is insufficient—as a larger (nonlocal) region of the structure affects values at a single point. The code here calculates nonlocal results without modifying the finite element software source code. The code is parallelized for large calculations typical of finite element analysis problems. 

Medical planning for space exploration is based on the “floating” blood bank model to store life-saving red blood cells (RBCs) for emergencies. The “floating” blood bank approach is not sufficient in cases where multiple crewmembers are affected by space anemia. In these situations, long-term preserved RBCs will be vital to guarantee the health and safety of crew members. Transfusable RBC units can only be refrigerated for 42 days or frozen at -80 C. However, storing frozen RBCs at -80 C is challenging during the confined condition of long-duration space flight. Freeze-dried, viable RBCs would be an appropriate alternative because they can be stored without cooling, are predicted to have a shelf-life of years, and could be transfused immediately after rehydration. This study explores if freeze-dried RBCs can be rehydrated and transfused in reduced gravity with similar outcomes in recovery as observed at Earth gravity. Experiments analyzing freeze-dried RBC recoveries, rehydration fluid dynamics, and transfusion flow rates were analyzed utilizing an experimental glovebox in simulated 0 g during parabolic flights. RBC recoveries and rehydration fluid dynamics for volumes of 5 mL and 10 mL were the same in simulated 0 g compared to results obtained at 1 g. A clinically acceptable range of flow rates for slow intravenous infusion and rapid fluid resuscitation was possible with the simple augmentation of a hand-pumped clinical pressure bag around a unit of rehydrated RBCs. The results demonstrate the potential feasibility of using freeze-dried cells for healthcare during deep-space exploration. 

Abstract. The Geoengineering Model Intercomparison Project (GeoMIP) has proposed multiple model experiments during phases 5 and 6 of the Climate Model Intercomparison Project (CMIP), with the latest set of model experiments proposed in 2015. With phase 7 of CMIP in preparation and with multiple efforts ongoing to better explore the potential space of outcomes for different solar radiation modifications (SRMs) both in terms of deployment strategies and scenarios and in terms of potential impacts, the GeoMIP community has identified the need to propose and conduct a new experiment that could serve as a bridge between past iterations and future CMIP7 experiments. Here we report the details of such a proposed experiment, named G6-1.5K-SAI, to be conducted with the current generation of scenarios and models from CMIP6 and clarify the reasoning behind many of the new choices introduced. Namely, compared to the CMIP6 GeoMIP scenario G6sulfur, we decided on (1) an intermediate emission scenario as a baseline (the Shared Socioeconomic Pathway 2-4.5), (2) a start date set in the future that includes both considerations for the likelihood of exceeding 1.5 °C above preindustrial levels and some considerations for a likely start date for an SRM implementation, and (3) a deployment strategy for stratospheric aerosol injection that does not inject in the tropical pipe in order to obtain a more latitudinally uniform aerosol distribution. We also offer more details regarding the preferred experiment length and number of ensemble members and include potential options for second-tier experiments that some modeling groups might want to run. The specifics of the proposed experiment will further allow for a more direct comparison between results obtained from CMIP6 models and those obtained from future scenarios for CMIP7.

 

Purpose Three Coupled Model Intercomparison Project Phase 5 models involved in the G4 experiment of the Geoengineering Model Inter-comparison Project (GeoMIP) project were used to investigate the impact of stratospheric aerosol injection (SAI) on the mean surface air temperature and precipitation extremes in Africa. Design/methodology/approach This impact was examined under G4 and Representative Concentration Pathway (RCP) 4.5 scenarios on the total precipitation, the number of rainy days (RR1) and of days with heavy rainfall (R20 mm), the rainfall intensity (SDII), the maximum length of consecutive wet (CWD) and dry (CDD) days and on the maximum rainfall in five consecutive days (Rx5day) across four regions: Western Africa (WAF), Eastern Africa (EAF), Northern Africa and Southern Africa (SAF). Findings During the 50 years (2020–2069) of SAI, mean continental warming is −0.40°C lower in G4 than under RCP4.5. During the post-injection period (2070–2090), the temperature continues to increase, but at a lower rate (−0.19°C) than in RCP4.5. During SAI, annual rainfall in G4 is significantly greater than in RCP4.5 over the high latitudes (especially over SAF) and lower over the tropics. The termination of SAI leads to a significant increase of rainfall over Sahel and EAF and a decrease over SAF and Guinea Coast (WAF). Practical implications Compared to RCP4.5, SAI will contribute to reducing significantly regional warming but with a significant decrease of rainfall in the tropics where rainfed agriculture account for a large part of the economies. After the SAI period, the risk of drought over the extratropical regions (especially in SAF) will be mitigated, while the risk of floods will be exacerbated in the Central Sahel. Originality/value To meet the Paris Agreement, African countries will implement mitigation measures to contribute to keep the surface air temperature below 2°C. Geoengineering with SAI is suggested as an option to meet this challenge, but its implication on the African climate system needs a deep investigation in the aim to understand the impacts on temperature and precipitation extremes. To the best of the authors’ knowledge, this study is the first to investigate the potential impact of SAI using the G4 experiment of GeoMIP on temperature and precipitation extremes of the African continent. 

Abstract. The Geoengineering Model Intercomparison Project (GeoMIP) is a coordinating framework, started in 2010, that includes a series of standardized climate model experiments aimed at understanding the physical processes and projected impacts of solar geoengineering. Numerous experiments have been conducted, and numerous more have been proposed as “test-bed” experiments, spanning a variety of geoengineering techniques aimed at modifying the planetary radiation budget: stratospheric aerosol injection, marine cloud brightening, surface albedo modification, cirrus cloud thinning, and sunshade mirrors. To date, more than 100 studies have been published that used results from GeoMIP simulations. Here we provide a critical assessment of GeoMIP and its experiments. We discuss its successes and missed opportunities, for instance in terms of which experiments elicited more interest from the scientific community and which did not, and the potential reasons why that happened. We also discuss the knowledge that GeoMIP has contributed to the field of geoengineering research and climate science as a whole: what have we learned in terms of intermodel differences, robustness of the projected outcomes for specific geoengineering methods, and future areas of model development that would be necessary in the future? We also offer multiple examples of cases where GeoMIP experiments were fundamental for international assessments of climate change. Finally, we provide a series of recommendations, regarding both future experiments and more general activities, with the goal of continuously deepening our understanding of the effects of potential geoengineering approaches and reducing uncertainties in climate outcomes, important for assessing wider impacts on societies and ecosystems. In doing so, we refine the purpose of GeoMIP and outline a series of criteria whereby GeoMIP can best serve its participants, stakeholders, and the broader science community.