This paper presents detailed results of neutron imaging of argon bubble flows in a rectangular liquid gallium vessel with and without the application of external horizontal magnetic field. The developed image processing algorithm is presented and its capability to extract physical information from images of low signal-to-noise ratio is demonstrated. Bubble parameters, velocity components, trajectories and relevant statistics were computed and analysed. A simpler version of the code was applied to the output of computational fluid dynamics simulations that reproduced the experiment. This work serves to further validate the neutron radiography as a suitable method for monitoring gas bubble flow in liquid metals, as well as to outline procedures that might help others to extract data from neutron radiography images with a low signal-to-noise ratio resulting from high frame rate acquisitions required to resolve rapid bubble motion.

We investigate argon bubble flow in liquid gallium within a container large enough to avoid wall effects. Flow with and without applied horizontal magnetic field is studied. We demonstrate the successful capture and quantification of the effects of applied magnetic field using dynamic neutron radiography and the previously developed and validated robust image processing pipeline, supported by the in silico reproduction of our experiment. Significant reduction of the amplitude of bubble tilt angle variations due to applied horizontal magnetic field is successfully resolved through a 30 mm thick liquid metal layer. Our results clearly show the potential of expanding the range of gas/liquid metal systems that can be studied using downscaled though representative experimental setups.

This paper presents the results of numerical modelling of hygrothermal processes in test buildings situated in the Botanical garden of the University of Latvia. Long-term performance of wall, floor and ceiling insulating assemblies for five different buildings was simulated using WUFI Pro 6.3. On the experimental side, measurements of temperature and relative humidity at key points of assembles have been accumulated over a period of roughly six years and material samples were taken from building envelope materials for biological analysis. We found that our models rather successfully reproduce the experientially observed temperature and relative humidity dynamics. In the process, we established material models for building envelope components, as well as different parameters that we previously unknown. We also compared mould growth risk predictions via the Sedlbauer critical curve model derived from both simulations and experiment against the results of lab tests conducted on materials samples - all three were found to be in good agreement, indicating that the Sedlbauer model is applicable to local climate conditions, as well as further validating numerical models.

We showcase the dynamic mode decomposition (DMD) code developed for applications in twophase flow analysis. Vertical bubble chain flow in a rectangular vessel filled with liquid gallium is studied without and with applied static horizontal magnetic field (MF) and DMD is applied to the velocity fields computed via volume of fluid simulations. Flow patterns are investigated in the vessel and bubble reference frames. We demonstrate the effect of applied MF and gas flow rate on bubble wake flow and larger scale flow structures within the liquid metal vessel by examining velocity field mode statistics over trajectory time and total flow time, as well as the computed mode velocity fields.

In order to assess the sustainability of buildings with different types of insulating assemblies in the Latvian climate, a long-term test building monitoring experiment has been underway since 2013. There are a total of five test buildings on site with roughly six years' worth of accumulated temperature and humidity readings in the key parts of assemblies. This study is meant to quantify the mould presence in building walls, floor and ceiling by performing laboratory tests, assessing the number of colony-forming units, and comparing the results with mould risk predictions due to the isopleth model developed by Sedlbauer, using both the hygrothermal data derived from the sensors within buildings and the output of numerical simulations in WUFI Pro 6.3, a commercial software package. The analysis indicated good agreement between the lab tests and mould risk assessment using the data sets from the sensors, validating the applicability of the Sedlbauer model to the Latvian climate, while the comparisons between the numerically obtained forecasts and experimental data revealed dissimilarities that are largely due to imprecisions in material models and initial conditions.