Hao Cheng

TL;DR: A state-of-the-art review on various smart sensors based on piezoelectric effect and fiber optic technology, as well as corresponding techniques for bond-slip monitoring is presented.

TL;DR: The experimental results demonstrate that the proposed percussion method can identify different moisture levels in concrete with accuracy more than 98%.

TL;DR: A new non-destructive approach using the percussion method and voice recognition with support vector machine to detect the sandy deposits in the steel pipeline and demonstrates that Mel-Frequency Cepstrum Coefficients perform better in pipeline deposits detection and have great potential in acoustic recognition for structural health monitoring.

Abstract: Steel fiber concrete has higher tensile strength, higher fatigue strength and higher fracture toughness than traditional reinforced concrete. Because of these advantages, it is one of the most widely used types of material in water resources and hydropower engineering. In this paper, the Smart Aggregate (SA) sensors which made by sandwiched the water proofed piezoceramic patch into protective materials were casted into the steel fiber concrete specimens. The steel fiber concrete, which average compressive strength is 50 MPa, are divided into five groups according to different content of steel fiber (0, 30, 60, 90, 120) (kg/m3). Based on the electro-mechanical impedance signal which acquired from the Smart Aggregate (SA), the cracks and the damage status of steel fiber concrete can be detected. Specifically, the effects of axial compressive load were investigated by using step-by-step loading scheme which includes elastic, plastic and the destruction loading stage. A normalized Root-Mean-Square Deviation (RMSD) based analysis was developed to determine the relationship between destruction and impedance signal. The test results show that the normalized RMSD impedance damage index increases gradually with the increase of axial loading. It can be used to monitor the damage status of steel fiber concrete.

TL;DR: In this article , the polyphenol content in fresh sweet sorghum stalks was 5.77 mg/g after process optimization with 18 types of phenolic acids identified, and the extract had a total antioxidant capacity of 9.4 μmol Trolox/mL.