3 research outputs found
Micrometre-scale plasticity size effects in metals and ceramics: theory and experiment.
No full textPhDThis thesis comprises studies of size effects in the plasticity of metals and
ceramics at length scales of the order of micrometres and includes both experimental
work and theoretical development. Experimental results are presented for foil flexure
(nickel and copper)and nanoindentation (ceramics and hard metals).These studies
were conducted because existing data does not cover a range broad enough or with
sufficient precision to test various theories.
With the developed bending technique more accurate data is obtained covering
a wide range of strain, especially around the key region of the elastic-plastic
transition. Moreover, the interaction between grain and thickness size effect is
successfully studied by varying the ratio of grain size over thickness of the foils.
After carefully calibrating the indenters, the macroscopic indentation yield
strength for ceramics and high strength metals is determined in a direct way by using
spherical nanoindentation. The magnitude of size effect is significantly different
between metals and ceramics. By comparing the Berkovich and spherical indentation
size effect, the results implies that the contact size, a, is the most fundamental length
scale in the indentation size effect, independent of the indenter shape. The
indentation strength is found to be inversely scaled with the square root of a.
The slip-distance theory (based on (Conrad et al, 1967)) with an effective
length scale reconciling intrinsic and extrinsic size effects appears able to account
for the size effects in all contexts, without requiring strain gradient plasticity theory
or an implicit characteristic length
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
No full textAbstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
No full textAbstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
