In the paper, a research programme focused on determination of steel fibre dispersion in self-compacting concrete using the X-ray computed tomography method is presented. Large scale specimens were cast (in the form of walls 1.2 m × 1.2 m × 0.15 m), containing different types of steel fibre. The tests were conducted on beam specimens cut from each wall. Both traditional destructive tests (compressive strength, three point bending) and non-destructive tests (X-ray computed tomography imaging followed by image analysis) were performed. The X-ray computed tomography method allowed to precisely determine fibre dispersion in the whole volume of the walls. These results were compared with mechanical properties of cut beams and their original location in the walls. Differences in fibre volume and dispersion between top and bottom parts of the walls were observed. The influence of the fibre type and the casting point location was also significant. Longer fibres became more effectively orientated in parallel to the bending loading direction, resulting in enhancement of the mechanical properties of the concrete. Tests on 16 beams (cut from each wall), through load–deflection relations, provided a thorough picture of mechanical uniformity of the material properties inside the walls. The X-ray computed tomography imaging proved to be intuitive and accurate in the assessment of steel fibre dispersion.
In this study, we aim to assess and examine cognitive functions in Parkinson’s Disease patients using EEG recordings, with a central focus on characteristics associated with a cognitive decline. Based on neuropsychological evaluation using Mini-Mental State Examination, Montreal Cognitive Assessment, and Addenbrooke’s Cognitive Examination-III, 98 participants were divided into three cognitive groups. All the particpants of the study underwent EEG recordings with spectral analysis. The results revealed an increase in the absolute theta power in patients with Parkinson’s disease dementia (PD-D) compared to cognitively normal status (PD-CogN, ) and a decrease in global relative beta power in PD-D compared to PD-CogN (). An increase in theta relative power in the left temporal region (), left occipital region (), and right occipital region () were observed in PD-D compared to PD-N. The global alpha/theta ratio and global power spectral ratio significantly decreased in PD-D compared to PD-N (p = 0.001). In conclusion, the increase in relative theta power and the decrease in relative beta power are characteristic changes in EEG recordings in PD patients with cognitive impairment. Identifying these changes can be a useful biomarker and a complementary tool in the neuropsychological diagnosis of cognitive impairment in Parkinson’s Disease.