With time hydrogen gas is produced, which can accumulate in bubbles. These pockets of gas may result in bitumen overflowing out of the waste containers and could result in spread of radioactivity. Muon Scattering Tomography is a non-invasive scanning method developed to examine the unknown content of nuclear waste drums. Here we present a method which allows us to successfully detect bubbles larger than 2 litres and determine their size with a relative uncertainty resolution of 1.55 ± 0.77%. Furthermore, the method allows to make a distinction between a conglomeration of bubbles and a few smaller gas volumes in different locations.

Inspection of the world's ageing population of reinforced concrete infrastructure isamultibillion dollar problem. Historically, it has not been uncommon for structures to deviate from their designs,or for design drawings to be lost. This leaves asset managers the challenging task of making structural health assessments and maintenance decisions with incomplete knowledge. While current techniques for detecting rebars in concrete are typically limited to penetration depths ofless than50 cm, muon scattering tomography (MST) is a non-destructive, noninvasive technique which shows great promise for high-depth 3D concrete imaging. This paper uses Monte Carlo simulations to demonstrate that MST can be used to detect and locate 100 cmlength rebars with a diameter of 33.7±7.3 mm independently of the rebar's location within a concrete structure. This corresponds to a volume of inclusion of 894±386 cm 3 . The volume of the inclusion can be reconstructed with a resolution of 5.4±0.3% for volumes above 2 500 cm 3 . It is furthermore demonstrated that 30 mm diameter rebars can be distinguished as two separate objects provided their separation is more than 40-60 mm, and that single and double layers of rebars are distinguishable using the technique. It is anticipated that MST could inform practical studies which support more informed maintenance and modeling, eventually allowing digital twins to be created for a larger subset of historical steel and concrete structures.

Inspection of ageing, reinforced concrete structures is a world-wide challenge. Existing non-destructive evaluation techniques in civil and structural engineering have limited penetration depth and don’t allow to precisely ascertain the configuration of reinforcement within large concrete objects. The big challenge for critical infrastructure (bridges, dams, dry docks, nuclear bioshields etc.) is understanding the internal condition of the concrete and steel, not just the location of the reinforcement. In most new constructions the location should be known and recorded in the as-built drawings, where these might not exist due to poor record keeping for older structures. Muon scattering tomography is a non-destructive and non-invasive technique which shows great promise for high-depth 3D concrete imaging. Previously, we have demonstrated that individual bars with a diameter of 33.7 ± 7.3 mm can be located using muon scattering tomography. Here we present an improved method that exploits the periodicity of bar structures. With this new method, reinforcement with bars down to 6 mm thickness can be detected and imaged.

Haemolysin a (HlyA) produced by cell-detaching Escherichia coli, a putative new class of enteric pathogen, is considered to be the main factor responsible for detachment of cells cultured in vitro. HlyA is one of the few E. coli proteins actively secreted into the medium during exponential growth. In the present study 27 HlyA-positive E. coli isolates, randomly selected from stool specimens, produced a cell-bound haemolysin that was detectable during the exponential and stationary growth phases. The influence of both cell-free and cell-bound haemolysins of the selected isolates on cell-detaching activity of E. coli in vitro was determined. The results suggest that cell-bound haemolysin rather than cell-free HlyA was responsible for the cell-detaching activity of E. coli strains tested.

Inspection of ageing, reinforced concrete structures is a world-wide challenge. Existing evaluation techniques in civil and structural engineering have limited penetration depth and do not allow to precisely ascertain the configuration of reinforcement within large concrete objects. The big challenge for critical infrastructure (bridges, dams, dry docks, nuclear bioshields etc.) is understanding the internal condition of the concrete and steel, not just the location of the reinforcement. Muon scattering tomography is a non-destructive and non-invasive technique which shows great promise for high-depth 3D concrete imaging. Here a method is presented to locate reinforcement meshes placed in a large-scale concrete object. A reinforcement mesh was simulated as two layers of 2 m long bars, forming a mesh. Two layers of the mesh were placed at several distances from each other inside a large concrete block. Previously, we have shown that using our autocorrelation technique for single meshes inside the concrete and using only one week worth of data taking, bars with a diameter of 7 mm and larger, could easily be detected for a 10 cm mesh spacing. The signal for 6 mm diameter bar exceeds the background and becomes very clear after two weeks of data taking. Here we show that we can detect the vertical positions of two mesh layers inside the concrete. This is a very important result for non-destructive evaluation of civil structures.