Nanoindentation study of the temperature dependence of plastic instability in Al alloys.

Plastic instability, i.e. repetitive yielding that occurs during plastic deformation at low strain rates and moderately high temperatures, results in severe strain localization, reduction in ductility and formation of surface striations during forming processes. In order to gain insights into the different rate controlling mechanisms that govern PLC type plastic instability, it is useful to probe its thermal dependence. Such investigations facilitate the estimation of thermally activated parameters associated with the phenomenon and provide insights into the underlying microscopic mechanisms. In this work, we present an elevated temperature nanoindentation test method for characterizing the thermal dependence of plastic instability and assessing the activation energy associated with the phenomenon in Al–Mg and Al–Li based alloys. The method exploits the nanoscale force–displacement resolution capabilities of the nanoindenter, precludes the ambiguities inherent in the uniaxial testing based methods and offers increased reliability because of the statistical significance of the data achieved. Results show that the activation energies established by this method for these two alloys are consistent with values derived with other methods, and reflect the different rate controlling mechanisms associated with plastic instability in these alloy systems. Please click Additional Files below to see the full abstract

Grain-scale investigation of the anisotropy of PLC-type plastic instability

Various aspects of Portevin Le-Chatelier (PLC) type plastic instability, particularly the influence of strain rate, temperature and precipitation on the phenomenon have been investigated. Such investigations give insights into the underlying governing mechanisms and provide the basis for developing mechanistic and numerical models for these mechanisms. One aspect that is yet to be understood is the influence of anisotropy on plastic instability. So far, experimental efforts aimed at understanding this influence have been focussed on the influence of sample orientation and texture. However, direct measurement of the response of single crystals during uniaxial testing is essential for accurate characterization of the influence of anisotropy. Yet, such an endeavour is largely limited by the difficulty of producing single crystals of technical alloys. Insight into the orientation dependence of plastic instability is thus achieved in this work with a combination of spherical nanoindentation of single grains of Mg AZ91 and local orientation image analysis of cross sections of the nanoindents. Our results indicate that the local stresses arising from the underlying mechanisms that govern plastic instability in this alloy are strongly orientation dependent. In this talk, we will highlight the origin of the orientation dependence and the influence of twinning, and discuss the implications for macroscopic deformatio

Implementation Guidance for Wood Harvesting and Storage

This implementation guidance focuses on carbon removal and sequestration via wood harvesting and storage (WHS), a process where woody biomass, with the embedded carbon, is stored for long timescales in shallow geologic storage. The engineering structure designed to ensure such durable storage by preventing biomass decomposition is called a Wood Vault. This guidance contains the requirements for a basic Wood Vault project, and is intended to aid project developers, verifiers, and registries in this space. It describes a set of requirements that govern the end-to-end process of carbon removal and sequestration. This includes carbon accounting, wood sourcing via wood residual (WR) utilization, Wood Vault construction and maintenance, as well as processes for monitoring, verification, and credit issuance. Carbon accounting requirements include baseline, or counterfactual specification, and full life cycle analysis (LCA) within a specified process boundary. For the vault itself, the guidance describes a buried vault with the burial chamber covered by a layer of low permeability material to create anoxic condition. Other types of vaults can also be used to adjust to local environmental, transport, and economic constraints. Monitoring and verification requirements include in-situ sensors, gas sampling, sample excavations, and site maintenance. This guidance also contemplates land ownership and legal assurances, as well as environmental and societal impact assessments. The implementation guidance concludes with recommendations regarding auditing, certification and carbon credit issuance

On the mechanistic origin of the enhanced strength and ductility in rare earth-based Mg alloys

The applicability of classical wrought Mg alloys is limited by their comparatively poor room temperature ductility and low yield strength. Conversely, various experimental and computational efforts do confirm that low concentrations of rare earth (RE) in Mg significantly improves these properties. However, the mechanistic origin of these improvements are still been debated. In order to contribute to the discourse, we carried out in-depth comparison of deformation modes in single crystals of pure Mg and a homogenized Mg–0.75 at.% Gd alloy oriented for twinning, pyramidal- and basal-slip using a combination of microcompression testing, scanning transmission electron microscopy and small angle x-ray scattering technique. We observed a fivefold increase in basal CRSS and a fourfold decrease of the pyramidal/basal CRSS (P/B) ratio as a result of Gd addition. We also observed that slip was planar in the basal orientation of the alloy but wavy in pure Mg. Pyramidal slip and twinning activity in the two systems were however similar; an indication that the same mechanisms underlie deformation in these orientation. We show that the observed planar slip, increase in basal CRSS and decrease in P/B ratio are consequence of Gd-rich short-range ordered (SRO) clusters in the alloy. Our analysis show that these SRO clusters lead to significantly high strengths in the basal orientation since additional stress is required to destroy the ordering therein. This not only leads to a dramatic increase in yield strength, given the drastic reduction in P/B CRSS ratio, it should also significantly promote pyramidal slip activities in polycrystals and by extension ductility improvements

Scrotal and Penile Erythrodysesthesia Associated with Neoadjuvant Capecitabine Chemoradiation.

Capecitabine, a prodrug of fluorouracil, is a component of many chemotherapy regimens used to treat a wide variety of malignancies. One of the most common adverse reactions experienced by those who have been exposed to capecitabine is palmar-plantar erythrodysesthesia (PPE). PPE is a cutaneous manifestation of chemotherapy-related drug toxicity that has signs and symptoms of erythema, edema, pain, ulceration, or desquamation of the palms of the hands and soles of the feet. The signs and symptoms occur with varying severity. There are few reports of the genitalia being similarly affected. The following case describes a patient with locally advanced rectal cancer who experienced erythrodysesthesia secondary to a capecitabine-containing neoadjuvant chemoradiation regimen that primarily and most significantly involved the genitalia

Ambitions for Palliative and End of Life Care: Mapping Examples of Use in Practice

The Ambitions for Palliative and End of Life Care: a national framework for local action was originally released in 2015 and relaunched in 2021 for an additional five years. Developed through partnership, the Framework provides a vision for action focused on six ambitions underpinned by eight foundations. This report shares findings from a project about how people have used the Framework in England. It involved mapping exercise based on a survey to identify examples of practice of how the Framework. There are examples of services using the Framework across England. The majority of examples came from hospice and/or specialist palliative care settings. Each person is seen as an individual (Ambition 1) was most frequently identified as a primary focus for services. Each community is prepared to help (Ambition 6) was least frequently identified as a primary focus. The report includes case studies for each Ambition; they have not been evaluated as part of this project and are therefore not presented as examples of ‘best practice’. The Framework is most frequently being used to provide guiding principles and to support education and training. Examples of use in local policy, commissioning and developing business cases were also identified. Survey respondents identified the Framework as having a role in enabling a process of service development from strategic conception to practical delivery, although there are persistent concerns about how ambitions can be meaningfully operationalised, measured, and resourced. Overall, the Framework appears to be well received by survey respondents. It is perceived to provide a shared language about what matters in palliative and end of life care. There is appetite for further education and knowledge exchange about the Framework and how people have used it. More work could be done to embed the use of the Framework in local strategies and partnership development, as well as supporting initiatives to realise Ambition 6. Suggested next steps include further research; encouraging the use of the Framework at strategy and commissioning levels; additional education, training and knowledge exchange; and focusing on carers and communities. Further in-depth case study analysis and additional research will be conducted by the project team starting in April 2022. This will focus on how a range of stakeholders understand, interpret, and implement the Framework

Rapid response of the Norwegian Atlantic Slope Current to wind forcing

Under embargo until: 2023-07-11We explore drivers of variability in the Norwegian Atlantic Slope Current, which carries relatively warm Atlantic Water toward the Barents Sea and Arctic Ocean, using Copernicus Marine Environment Monitoring Service (CMEMS) satellite altimetry data and TOPAZ4 ocean reanalysis data. Previous studies have pointed to a variety of causes, on a variety of time scales. We use data with daily resolution to investigate day-to-day changes in ocean transport across three sections crossing the shelf-slope of Norway (Svinøy, Gimsøy, and the Barents Sea Opening). The highest (lowest) extremes in transport at all sections develop over two days as a cyclonic (anticyclonic) atmospheric pressure system approaches from the southwest, piling up (extracting) water at the coast of Norway. The actual peak is reached when the pressure system passes the site of measurement, and the transport then relaxes for the next two days as the system continues northward along the coast. Other sources of short-term variability, such as propagating continental shelf waves and baroclinic instability, are unlikely to yield covariability over large separations. Monthly variability in the current can also be explained by passing weather systems since their numbers and intensity vary greatly from month to month. Many studies of longer-term variability, especially in the Barents Sea Opening, have pointed to the North Atlantic Oscillation (NAO) as the main cause of variability. Our results show that passing weather systems offer a better explanation of month-to-month variability.publishedVersio

Microbial and metabolic succession on common building materials under high humidity conditions.

Despite considerable efforts to characterize the microbial ecology of the built environment, the metabolic mechanisms underpinning microbial colonization and successional dynamics remain unclear, particularly at high moisture conditions. Here, we applied bacterial/viral particle counting, qPCR, amplicon sequencing of the genes encoding 16S and ITS rRNA, and metabolomics to longitudinally characterize the ecological dynamics of four common building materials maintained at high humidity. We varied the natural inoculum provided to each material and wet half of the samples to simulate a potable water leak. Wetted materials had higher growth rates and lower alpha diversity compared to non-wetted materials, and wetting described the majority of the variance in bacterial, fungal, and metabolite structure. Inoculation location was weakly associated with bacterial and fungal beta diversity. Material type influenced bacterial and viral particle abundance and bacterial and metabolic (but not fungal) diversity. Metabolites indicative of microbial activity were identified, and they too differed by material