Energy-resolved neutron imaging for reconstruction of strain introduced by cold working

Energy-resolved neutron transmission imaging is used to reconstruct maps of residual strains in drilled and cold-expanded holes in 5-mm and 6.4-mm-thick aluminum plates. The possibility of measuring the positions of Bragg edges in the transmission spectrum in each 55 × 55 µm2 pixel is utilized in the reconstruction of the strain distribution within the entire imaged area of the sample, all from a single measurement. Although the reconstructed strain is averaged through the sample thickness, this technique reveals strain asymmetries within the sample and thus provides information complementary to other well-established non-destructive testing methods

Immunisation of migrants in EU/EEA countries: Policies and practices

In recent years various EU/EEA countries have experienced an influx of migrants from low and middle-income countries. In 2018, the “Vaccine European New Integrated Collaboration Effort (VENICE)” survey group conducted a survey among 30 EU/EEA countries to investigate immunisation policies and practices targeting irregular migrants, refugees and asylum seekers (later called “migrants” in this report). Twenty-nine countries participated in the survey. Twenty-eight countries reported having national policies targeting children/adolescent and adult migrants, however vaccinations offered to adult migrants are limited to specific conditions in seven countries. All the vaccinations included in the National Immunisation Programme (NIP) are offered to children/adolescents in 27/28 countries and to adults in 13/28 countries. In the 15 countries offering only certain vaccinations to adults, priority is given to diphtheria-tetanus, measles-mumps-rubella and polio vaccinations. Information about the vaccines given to child/adolescent migrants is recorded in 22 countries and to adult migrants in 19 countries with a large variation in recording methods found across countries. Individual and aggregated data are reportedly not shared with other centres/institutions in 13 and 15 countries, respectively. Twenty countries reported not collecting data on vaccination uptake among migrants; only three countries have these data at the national level. Procedures to guarantee migrants’ access to vaccinations at the community level are available in 13 countries. In conclusion, although diversified, strategies for migrant vaccination are in place in all countries except for one, and the strategies are generally in line with international recommendations. Efforts are needed to strengthen partnerships and implement initiatives across countries of origin, transit and destination to develop and better share documentation in order to guarantee a completion of vaccination series and to avoid unnecessary re-vaccination. Development of migrant-friendly strategies to facilitate migrants' access to vaccination and collection of vaccination uptake data among migrants is needed to meet existing gaps

Residual Stress and Critical Crack Size before and after Post-Weld Heat-Treatment

Post-weld heat-treatment (PWHT) is performed to reduce residual stress, but is not always possible to perform. The residual stresses on a thick section weld on a gas pipeline were determined before and after PWHT to assess residual stress and critical defect sizes

Assessment of residual stress, hardness, and defect tolerance in a tee joint, as-welded and after post-weld heat treatment

The risk of hydrogen-assisted cold cracking (HACC) is often conflated with the risk of brittle fracture. However, if delayed non-destructive testing (NDT) shows there are no defects, or defects below the critical crack size, then brittle fracture is not possible. Post-weld heat treatment (PWHT) is known to reduce the risk of HACC but is not always possible to perform.To assess the effects of PWHT, the residual stresses and hardness values were measured before and after PWHT to assess the effects of PWHT on HACC susceptibility and on the critical defect sizes.The residual stresses were lower than code-based estimates. PWHT reduced the residual stress and hardness, and increased the critical crack size

Neutron diffraction residual stress measurements of welds made with pulsed tandem gas metal arc welding (PT-GMAW)

Pulsed tandem gas metal arc welding (PT-GMAW) is being developed to increase productivity and minimise weld-induced distortion in ship-building. The PT-GMAW process was used in pulse-pulse mode to butt-weld two different strength and thickness steels; the residual stress and hardness profiles of the welds are reported and correlated