Damage detection in cementitious materials with optimized absolute electrical resistance tomography

Electrical resistance tomography (ERT) serves as a non-invasive, non-destructive, non-radioactive imaging technique. It has potential applications in industrial and biological imaging. This paper presents an optimized inverse algorithm, named Newton’s Constrained Reconstruction Method (NCRM), to detect damage in cementitious materials. Several constraints were utilized in the proposed algorithm to optimize initial parameters. The range and spatial distribution of conductivities within the sample were chosen as two main constraints. Two sets of numerical and a set of experimental voltage data were used to reconstruct conductivity distribution images based on this algorithm. To evaluate the quality of reconstructed images, two image quality evaluation indicators, correlation coefficient and position error were used. Results show that the proposed algorithm NCRM has the ability to enhance the reconstructed image quality with fewer artifacts and has better positioning accuracy.

Envelope reconstruction of speech and music highlights stronger tracking of speech at low frequencies

The human brain tracks amplitude fluctuations of both speech and music, which reflects acoustic processing in addition to the encoding of higher-order features and one’s cognitive state. Comparing neural tracking of speech and music envelopes can elucidate stimulus-general mechanisms, but direct comparisons are confounded by differences in their envelope spectra. Here, we use a novel method of frequency-constrained reconstruction of stimulus envelopes using EEG recorded during passive listening. We expected to see music reconstruction match speech in a narrow range of frequencies, but instead we found that speech was reconstructed better than music for all frequencies we examined. Additionally, models trained on all stimulus types performed as well or better than the stimulus-specific models at higher modulation frequencies, suggesting a common neural mechanism for tracking speech and music. However, speech envelope tracking at low frequencies, below 1 Hz, was associated with increased weighting over parietal channels, which was not present for the other stimuli. Our results highlight the importance of low-frequency speech tracking and suggest an origin from speech-specific processing in the brain.

Envelope reconstruction of speech and music highlights unique tracking of speech at low frequencies

The human brain tracks amplitude fluctuations of both speech and music, which reflects acoustic processing in addition to the processing of higher-order features and one’s cognitive state. Comparing neural tracking of speech and music envelopes can elucidate stimulus-general mechanisms, but direct comparisons are confounded by differences in their envelope spectra. Here, we use a novel method of frequency-constrained reconstruction of stimulus envelopes using EEG recorded during passive listening. We expected to see music reconstruction match speech in a narrow range of frequencies, but instead we found that speech was reconstructed better than music for all frequencies we examined. Additionally, speech envelope tracking at low frequencies, below 1 Hz, was uniquely associated with increased weighting over parietal channels. Our results highlight the importance of low-frequency speech tracking and its origin from speech-specific processing in the brain.

Housebuilding of the Itkul Culture population in the subtaiga — forest-steppe Trans-Urals

This paper presents the results of the analysis of housebuilding tradition and graphical reconstruction of nine buildings from three stages of the eastern branch of the Itkul Culture (end of the 8th — 6th c. BC): Itkul (end of the 8th — first half of the 7th c. BC); Karagay-Aulsky (second half of the 7th c. BC); and Vak-Kurovsky (6th c. BC). The fortified settlements, whose buildings have been studied, are located in the valley of the Tobol River (subtaiga — northern forest-steppe zone, Western Siberia): Karagai Aul 1; Karagai Aul 4; Vak-Kur 2; and Sanatoriy Lesnye Gorki 1. By means of constrained reconstruction based on the analysis of planigraphy and stratigraphy of the excavation site, basic elements of the building frame, viz., the postholes marking the boundary and belonging to the building structure, were identified. Then the specifics of the building frame, techniques employed in construc-tion of walls and roof, and building materials were determined. In the final step of the reconstruction, a series of drawings of the buildings were created. As a result of the analysis of the building remains, a long-lasting house-building tradition of the western Itkul Culture population has been recorded — the use of a pile-dwelling structure built on the day surface. In terms of the shape, elongated sub-rectangular and polygonal-rounded dwellings have been identified. The wall framework consisted of two pillars joined by a beam at the top. These modules consti-tuted perimeter of the structure and were held together by a second row of joists. The framework of the walls and the ridge beam were fixed to each other by scaffold poles placed on the ridge beam at one end and on the wall joist at the other end. The space between the frame elements was filled with tilted timber logs, whole or split lengthwise, and the walls at the top would be insulated with bark and hay or have a soil filler. The roof of the buil-dings was mainly double-slope and a four-slope roof has been recorded only in one instance. The exit from the building was located in one of the walls, usually the short (face) wall. Annexes (lofts?) have been recorded for four buildings. The pile-dwelling structures of above-ground type have a broad range of territorial and chronological analogies; although in the Tobol River region at the turn of the Bronze to the Early Iron Age they appeared in a developed form. The origins of this phenomenon in the studied territory can be established by further research.