Advancing characterisation with statistics from correlative electron diffraction and X-ray spectroscopy, in the scanning electron microscope.

The routine and unique determination of minor phases in microstructures is critical to materials science. In metallurgy alone, applications include alloy and process development and the understanding of degradation in service. We develop a correlative method, exploring superalloy microstructures, which are examined in the scanning electron microscope (SEM) using simultaneous energy dispersive X-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD). This is performed at an appropriate length scale for characterisation of carbide phases' shape, size, location, and distribution. EDS and EBSD data are generated using two different physical processes, but each provide a signature of the material interacting with the incoming electron beam. Recent advances in post-processing, driven by 'big data' approaches, include use of principal component analysis (PCA). Components are subsequently characterised to assign labels to a mapped region. To provide physically meaningful signals, the principal components may be rotated to control the distribution of variance. In this work, we develop this method further through a weighted PCA approach. We use the EDS and EBSD signals concurrently, thereby labelling each region using both EDS (chemistry) and EBSD (crystal structure) information. This provides a new method of amplifying signal-to-noise for very small phases in mapped regions, especially where the EDS or EBSD signal is not unique enough alone for classification

Effectiveness of supervised physical therapy in the early period after arthroscopic partial meniscectomy

Background and Purpose. Controversy exists about the effectiveness of physical therapy after arthroscopic partial meniscectomy. This randomized controlled trial evaluated the effectiveness of supervised physical therapy with a home program versus a home program alone. Subjects. Eighty-four patients (86% males; overall mean age=39 years, SD=9, range=21–58; female mean age=39 years, SD=9, range=24–58; male mean age=40, SD=9, range=21–58) who underwent an uncomplicated arthroscopic partial meniscectomy participated. Methods. Subjects were randomly assigned to either a group who received 6 weeks of supervised physical therapy with a home program or a group who received only a home program. Blinded test sessions were conducted 5 and 50 days after surgery. Outcome measures were: (1) Hughston Clinic questionnaire, (2) Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and EuroQol EQ-5D (EQ-5D) questionnaires, (3) number of days to return to work after surgery divided by the Factor Occupational Rating System score, (4) kinematic analysis of knee function during level walking and stair use, and (5) horizontal and vertical hops. Results. No differences between groups were found for any of the outcomes measured. Discussion and Conclusion. The results indicate that the supervised physical therapy used in this study is not beneficial for patients in the early period after uncomplicated arthroscopic partial meniscectomy

Quantitative precipitate classification and grain boundary property control in Co/Ni-base superalloys

A correlative approach is employed to simultaneously assess structure and chemistry of (carbide and boride) precipitates in a set of novel Co/Ni-base superalloys. Structure is derived from electron backscatter diffraction (EBSD) with pattern template matching, and chemistry obtained with energy dispersive X-ray spectroscopy (EDS). It is found that the principal carbide in these alloys is Mo and W rich with the M6C structure. An M2B boride also exhibiting Mo and W segregation is observed at B levels above approximately 0.085 at. pct. These phases are challenging to distinguish in an SEM with chemical information (EDS or backscatter Z-contrast) alone, without the structural information provided by EBSD. Only correlative chemical and structural fingerprinting is necessary and sufficient to fully define a phase. The identified phases are dissimilar to those predicted using ThermoCalc. We additionally perform an assessment of the grain boundary serratability in these alloys, and observe that significant amplitude is only obtained in the absence of pinning intergranular precipitates

Improving health-related quality of life and reducing suicide in primary care: Can social problem–solving abilities help?

Problem-solving deficits and poor health–related quality of life are associated with suicide risk; yet, little is known about the interrelations between these variables. In 220 primary care patients, we examined the potential mediating role of physical and mental health–related quality of life on the relation between social problem–solving ability and suicidal behavior. Participants completed the Suicidal Behaviors Questionnaire-Revised, Social Problem Solving Inventory-Revised, and Short-Form 36 Health Survey. Utilizing bootstrapped mediation, our hypotheses were partially supported; mediating effects were found for mental health–related quality of life on the relation between social problem-solving and suicidal behavior. Physical health–related quality of life was not a significant mediator. Greater social problem–solving ability is associated with better mental health–related quality of life and, in turn, to less suicidal behavior. Interventions promoting social problem–solving ability may increase quality of life and reduce suicide risk in primary care patients

AstroEBSD Superalloy Example Data

This is an example dataset for use with AstroEBSD. It is a compressed version of the one found at 10.5281/zenodo.3617455, the data bundle for our paper 'Advancing characterisation with statistics from correlative electron diffraction and X-ray spectroscopy, in the scanning electron microscope' - https://doi.org/10.1016/j.ultramic.2020.112944. The .h5 file contains EBSD patterns and EDS spectra. The zip file contains an example analysis, including EDS spectra quantification in a .xls file, which is required for the EDS post-analysis.This is an example dataset for use with AstroEBSD. It is a compressed version of the one found at 10.5281/zenodo.3617455, the data bundle for our paper 'Advancing characterisation with statistics from correlative electron diffraction and X-ray spectroscopy, in the scanning electron microscope' - https://doi.org/10.1016/j.ultramic.2020.112944. The .h5 file contains EBSD patterns and EDS spectra. The zip file contains an example analysis, including EDS spectra quantification in a .xls file, which is required for the EDS post-analysis.

Data bundle for "Spherical-angular dark field imaging and sensitive microstructural phase clustering with unsupervised machine learning"

Prepared by Tom McAuliffe ([email protected]) This repository is a release of the raw data and analysis results for: 'Spherical-angular dark field imaging and sensitive microstructural phase clustering with unsupervised machine learning' The raw data is given as 'yprime.h5' - this contains patterns and metadata in the Bruker-exported format. Scripts for dataset decomposition into latent factors are given in 'Scripts'. Our spherical analysis code is included in 'SphericalAngleDF'. Outputs of our analysis code are contained in 'Analysis'. Figures for the paper are included in 'Figures'.Prepared by Tom McAuliffe ([email protected]) This repository is a release of the raw data and analysis results for: 'Spherical-angular dark field imaging and sensitive microstructural phase clustering with unsupervised machine learning' The raw data is given as 'yprime.h5' - this contains patterns and metadata in the Bruker-exported format. Scripts for dataset decomposition into latent factors are given in 'Scripts'. Our spherical analysis code is included in 'SphericalAngleDF'. Outputs of our analysis code are contained in 'Analysis'. Figures for the paper are included in 'Figures'.1.

Effect of high temperature service on the complex through-wall microstructure of centrifugally cast HP40 reformer tube

Centrifugally cast reformer tubes are used in petrochemical plants for hydrogen production. Due to the conditions of hydrogen production, reformer tubes are exposed to high temperature which causes creep damage inside the microstructure. In this study, two different ex-service HP40 alloy reformer tubes which come from the same steam reformer unit have been compared by microstructural characterisation performed at a range of length scales from mm to um. Analyses performed by EBSD (Electron Backscatter Diffraction), EDS (Energy Dispersive X-ray Spectroscopy) and PCA (Principal Component Analysis) show that both tubes have similar microstructural constituents, with the presence of an austenitic matrix and M23C6, G phase and M6C carbides at the grain boundaries. Even if both tubes have a similar microstructure, one tube due to it localisation inside the steam reformer unit presents a region with more micro cracks which may indicate that this tube have accumulated more creep damage than the other one