Mapping metals in feathers

Synchrotron technique promising for tracing metals in nature

University of Saskatchewan (USask) and Environment and Climate Change Canada (ECCC)  researchers have mapped metals in bird feathers, a technique that could help make environmental monitoring less destructive.

In a recent paper published in X-ray Spectrometry, researchers used the Canadian Light Source (CLS) synchrotron at USask to examine the level and distribution of zinc in feathers from birds that were fed high-zinc diets.

“The same technique could be applied to toxic metals like mercury, even at low concentrations,” says Agriculture and Agri-Food Canada scientist Fardausi Akhter. “You could just take a feather from the bird and be able to show if it was exposed to toxic metals present in the environment.”

Akhter, a toxicologist interested in applying synchrotron techniques to environmental questions, first started working on this project with Graham Fairhurst, a USask avian ecophysiologist, when they were both working as postdocs supervised by Catherine Soos. Soos is a wildlife health specialist and research scientist at ECCC, and adjunct professor at USask (Department of Veterinary Pathology, Western College of Veterinary Medicine), whose research focuses on investigating impacts of large-scale environmental changes on wildlife health. Her team often uses feathers as tools to evaluate exposure to toxic metals, and impacts of exposure on health of wild birds.  

>Read more on the Canadian Light Source website

Image: Part of the research team at CLS (left to right): Fardausi (Shathi) Akhter, Jamille McLeod (ECCC), Bruce Pauli (ECCC), Peter Blanchard (CLS), Landon McPhee (ECCC), and Catherine Soos (ECCC)

Imaging dendrite growth in zinc-air batteries

SXCT captures unprecedented detail of dendrite formation, growth and dissolution

Modern life runs on rechargeable batteries, which power all of our mobile devices and are increasingly used to power vehicles and to store energy from renewable sources. We are approaching the limits of lithium-ion battery technology in terms of maximum energy capacity, and new technologies will be needed to develop higher capacity rechargeable batteries for the future. One class of promising candidates is metal-air batteries, in particular zinc-air batteries that have a high theoretical energy density and low estimated production costs. However, zinc-air batteries present certain challenges, in key areas such as cycle life, reversibility and power density. The formation of metal dendrites as the battery charges is a common cause of failure, as dendrites can cause internal short circuits and even thermal runaway. (Thermal runaway is a sequence of exothermic reactions that take place within the battery, leading to overheating and potentially resulting in fire or an explosion. It is also a problem in lithium-ion batteries, and the subject of ongoing research.) In work recently published in Joule, a team of researchers from Imperial College, London, University College London, the University of Manchester and the Research Complex at Harwell carried out in situ experiments investigating how dendritic growth can cause irreversible capacity loss, battery degradation and eventually failure.
>Read more on the Diamond Light Source website

Image: (extract, see full image here) Single dendrite and dendritic deposits inside and on top of the separator (FIB-SEM)

A closer look of zink behaviour under extreme conditions

Researchers have explored the phase diagram of zinc under high pressure and high temperature conditions, finding evidence of a change in its structural behaviour at 10 GPa. Experiments profited from the brightness of synchrotron light at ALBA and Diamond.

These results can help to understand the processes and phenomena happening in the Earth’s interior.

The field of materials science studies the properties and processes of solids to understand and discover their performances. Synchrotron light techniques permit to analyse these materials at extreme conditions (high pressure and high temperature), getting new details and a deep knowledge of them.

Studying the melting behaviours of terrestrial elements and materials at extreme conditions, researchers can understand the phenomena taking place inside them. This information is of great value for discovering how these materials react in the inner core of Earth but also for other industrial applications. Zinc is one of the most abundant elements in Earth’s crust and is used in multiple areas such as construction, ship-building or automobile.

>Read more on the ALBA website

Figure: P-T phase diagram of zinc for P<16 GPa and T<1600K. Square data points correspond to the X-ray diffraction measurements. Solid squares are used for the low pressure hexagonal phase (hcp) and empty symbols for the high pressure hexagonal phase (hcp’). White, red and black circles are melting points from previous studies reported in the literature. The triangles are melting points obtained in the present laser-heating measurements. In the onset of the figure is shown the custom-built vacuum vessel for resistively-heated membrane-type DAC used in the experiments at the ALBA Synchrotron.