Non-invasive 3D analysis of microplastic particles in sandy soil - Exploring feasible options and capabilities.

Increasingly, environmental research efforts seek to understand how the continuous input of microplastics into terrestrial environments alters soil physicochemical properties and affects plants and other soil biota. However, fundamental understanding is hampered by the destructive nature of current analytical techniques, which typically require the disruption of soil samples and often the removal of soil organic matter. This results in the irretrievable loss of essential information about soil microstructure and the spatial distribution of microplastic particles.

A mechanism of strain hardening and Bauschinger effect: shear-history-dependent microstructure of elasto-plastic suspensions.

Dispersing solid hard particles in an elasto-plastic material leads to important shear-history dependence of the behavior, namely strain hardening and Bauschinger effect. Strain hardening is observed as the progressive strengthening of a material during its plastic deformation and is usually associated with ductility, a property often sought after in composite materials to postpone fractures and failure. In addition, anisotropic mechanical properties are developed, the material resistance being larger in the direction of the imposed flow, which is referred to as the Bauschinger effect.

The effect of high relative humidity on a network of water-sensitive particles (couscous) as revealed by X-ray tomography.

Water significantly influences the mechanical behaviour of all granular materials but none as much as hygroscopic amorphous particles. With sufficiently high water content, particles can swell, agglomerate and their mechanical properties can be reduced, having direct effects on the macroscopic response of the material. In the food and pharmaceutical industry this can cause loss of product functionality.

Compact and versatile neutron imaging detector with sub-4μm spatial resolution based on a single-crystal thin-film scintillator.

A large and increasing number of scientific domains pushes for high neutron imaging resolution achieved in reasonable times. Here we present the principle, design and performance of a detector based on infinity corrected optics combined with a crystalline GdGaO : Eu scintillator, which provides an isotropic sub-4 µm true resolution. The exposure times are only of a few minutes per image.

Imaging local soil kinematics during the first days of maize root growth in sand.

Maize seedlings are grown in Hostun sand with two different gradings and two different densities. The root-soil system is imaged daily for the first 8 days of plant growth with X-ray computed tomography. Segmentation, skeletonisation and digital image correlation techniques are used to analyse the evolution of the root system architecture, the displacement fields and the local strain fields due to plant growth in the soil.

First visualisation of bacterial biofilms in 3D porous media with neutron microtomography without contrast agent.

Characterising bacterial biofilm growth in porous media is important for developing reliable numerical models of biofouling in industrial biofilters. One of the promising imaging methods to do that has been a recent successful application of X-ray microtomography. However, this technique requires a contrast agent (1-chloronaphtalene, for example) to distinguish biofilm from the liquid phase, which raises concern about biofilm disruption and impaired image interpretation.

Dual modality neutron and x-ray tomography for enhanced image analysis of the bone-metal interface.

The bone tissue formed at the contact interface with metallic implants, particularly its 3D microstructure, plays a pivotal role for the structural integrity of implant fixation. X-ray tomography is the classical imaging technique used for accessing microstructural information from bone tissue. However, neutron tomography has shown promise for visualising the immediate bone-metal implant interface, something which is highly challenging with x-rays due to large differences in attenuation between metal and biological tissue causing image artefacts.

Exploring the ontogenetic development of the inner ear in Aardvarks.

The aardvark is the last living Tubulidentata, an order of afrotherian mammals. Afrotheria is supported strongly by molecular analyses, yet sparingly by morphological characters. Moreover, the biology of the aardvark remains incompletely known.

What comes NeXT? - High-Speed Neutron Tomography at ILL.

Here, we report on a new record in the acquisition time for fast neutron tomography. With an optimized imaging setup, it was possible to acquire single radiographic projection images with 10 ms and full tomographies with 155 projections images and a physical spatial resolution of 200 µm within 1.5 s.

Shear thinning in non-Brownian suspensions.

We study the flow of suspensions of non-Brownian particles dispersed into a Newtonian solvent. Combining capillary rheometry and conventional rheometry, we evidence a succession of two shear thinning regimes separated by a shear thickening one. Through X-ray radiography measurements, we show that during each of those regimes, the flow remains homogeneous and does not involve particle migration.

Xylem resistance to embolism: presenting a simple diagnostic test for the open vessel artefact.

Xylem vulnerability to embolism represents an essential trait for the evaluation of the impact of hydraulics in plant function and ecology. The standard centrifuge technique is widely used for the construction of vulnerability curves, although its accuracy when applied to species with long vessels remains under debate. We developed a simple diagnostic test to determine whether the open-vessel artefact influences centrifuge estimates of embolism resistance.

Evidence for Hydraulic Vulnerability Segmentation and Lack of Xylem Refilling under Tension.

The vascular system of grapevine (Vitis spp.) has been reported as being highly vulnerable, even though grapevine regularly experiences seasonal drought. Consequently, stomata would remain open below water potentials that would generate a high loss of stem hydraulic conductivity via xylem embolism.

Mineral density of hypomineralised and sound enamel.

Molar Incisor Hypomineralisation (MIH) is a structural anomaly that affects the quality of tooth enamel and has important consequences for oral health. The developmentally hypomineralised enamel has normal thickness and can range in colour from white to yellow or brown. The purpose of the present study is to compare the mineral density of hypomineralised and normal enamel.

Frontoparietal Bone in Extinct Palaeobatrachidae (Anura): Its Variation and Taxonomic Value.

Palaeobatrachidae are extinct frogs from Europe closely related to the Gondwanan Pipidae, which includes Xenopus. Their frontoparietal is a distinctive skeletal element which has served as a basis for establishing the genus Albionbatrachus. Because little was known about developmental and individual variation of the frontoparietal, and its usefulness in delimiting genera and species has sometimes been doubted, we investigate its structure in Palaeobatrachus and Albionbatrachus by means of X-ray high resolution computer tomography (micro-CT).

A re-interpretation of the Eocene anuran Thaumastosaurus based on microCT examination of a 'mummified' specimen.

What originally appeared to be only an external cast of an anuran 'mummy' from the Quercy Phosphorites (southwestern France) was described as Rana plicata during the 19th century. Its geographical provenance is only vaguely known; therefore its precise age within the Paleogene was uncertain. The taxon was erected on the basis of the external morphology of the specimen, which includes few diagnostic characters.