Healthy human skin Kelvin‑Voigt fractional and spring‑pot biomarkers reconstruction using torsional wave elastography

This paper presents a novel method for reconstructing skin parameters using Probabilistic Inverse Problem (PIP) techniques and Torsional Wave Elastography (TWE) rheological modeling. A comprehensive examination was conducted to compare and analyze the theoretical, time-of-flight (TOF), and full-signal waveform (FSW) approaches. The objective was the identification of the most effective method for the estimation of mechanical parameters. Initially, the most appropriate rheological model for the simulation of skin tissue behavior was determined through the application and comparison of two models, spring pot (SP) and Kevin Voigt fractional derivative (KVFD). A numerical model was developed using the chosen rheological models. The collection of experimental data from 15 volunteers utilizing a TWE sensor was crucial for obtaining significant information for the reconstruction process. The study sample consisted of five male and ten female subjects ranging in age from 25 to 60 years. The procedure was performed on the ventral forearm region of the participants. The process of reconstructing skin tissue parameters was carried out using PIP techniques. The experimental findings were compared with the numerical results. The three methods considered (theoretical, TOF, FSW) have been used. The efficacy of TOF and FSW was then compared with theoretical method. The findings of the study demonstrate that the FSW and TOF techniques successfully reconstructed the parameters of the skin tissue in all of the models. The SP model’s the skin tissue η values ranged from 8 to 12 Pa ⋅ s, as indicated by the TOF reconstruction parameters. η values found by the KVFD model ranged from 4.1 to 9.3 Pa ⋅ s. The µ values generated by the KVFD model range between 0.61 and 96.86 kPa. However, FSW parameters reveal that skin tissue η values for the SP model ranged from 7.8 to 12 Pa ⋅ s. The KVFD model determined η values between 6.3 and 9.5 Pa ⋅ s. The KVFD model presents µ values ranging between 26.02 and 122.19 kPa. It is shown that the rheological model that best describes the nature of the skin is the SP model and its simplicity as it requires only two parameters, in contrast to the three parameters required by the KVFD model. Therefore, this work provides a valuable addition to the area of dermatology, with possible implications for clinical practice.Ministerio de Educación, Cultura y Deporte grant numbers DPI2017-83859-R, and EQC2018-004508-PMinisterio de Ciencia e Innovación grant numbers PID2020-115372RB-I00, PYC20 RE 072 UGRMinisterio de Sanidad, Servicios Sociales e Igualdad grant numbers DTS15/00093 and PI16/00339Instituto de Salud Carlos III y Fondos Feder; Junta de Andalucía grant numbers PI-0107-2017, PIN-0030- 2017 and IE2017-5537Consejería de Universidad, Investigación e Innovación de la Junta de Andalucía - proyecto P21.00182Listen2Future funding by 101096884 in HORIZON-KDT-JU-2021-2-RIA and by PCI2022-135048-2 by Ministerio de Ciencia e InnovaciónConsejería de economía, conocimiento, empresas y universidad and European Regional Development Fund (ERDF) SOMM17/6109,B-TEP- 026-IE2017-5537 and P18-RT-1653Proyectos Intramurales IBS. Granada INTRAIBS-2022-05. MCIN/AEI 10.13039/501100011 033 grant number PRE2021-096978 (Co-funded by European Social Fund “Investing in your future”)Ministerio de Universidades Ayudas para la recualificación del sistema universitario español, MS2022-96 (Co funded by European Union NextGenerationEU/PRTR)Open access charge: Universidad de Granada / CBUA

Evaluation of Half-Cell Potential Measurements for Reinforced Concrete Corrosion

The evaluation of half-cell potential measurements in reinforced concrete (RC) members can be a key issue for civil engineers. The primary reason for this is that the interpretation of half-cell potential measurements based on the available standards provides information related only to the possibility of corrosion in concrete, but it does not provide a clear perception of the influence of corrosion on the capacity of the RC members. The objective of this study is two-fold: (1) to explore the influence of corrosion level on the flexural capacity of RC members; and (2) to provide engineers with a better understanding of the correlation between half-cell potential measurements and flexural capacity of RC members. To establish this, twelve RC beams were cast and then exposed to accelerated corrosion utilizing an impressed current. After that, half-cell potential tests were performed on the entire surface of the beams. Next, a four-point loading test was performed on the beams to determine their flexural behavior. The analysis of measurements showed that there is a high positive correlation between the half-cell potential measurements and the flexural capacity of the tested beams which demonstrates the potential of half-cell measurements to predict the capacity degradation level of the RC beams due to corrosion