Application of Edge Computing in Structural Health Monitoring of Simply Supported PCI Girder Bridges.

This study proposes an innovative method for structural health monitoring of simply supported PCI girder bridges based on dynamic strain and edge computing. Field static and dynamic load tests were conducted on a bridge consisting of a span with newly replaced PCI girders and numerous spans with old PCI girders. Both the static and dynamic test results showed that the flexural rigidity of the old PCI girders decreased significantly due to deterioration. To improve the efficiency of on-site monitoring data transmission and data analysis, this study developed a smart dynamic strain gauge node with the function of edge computing. Continuous data with a sampling frequency of 100 Hz were computed at the sensor node. Among the computed results, only the maximum dynamic strain data caused by the passage of the heaviest vehicle within 1 min were transmitted. The on-site monitoring results indicated that under routine traffic conditions, the dynamic strain response of the new PCI girder was smaller than that of the deteriorated PCI girder. When the monitored dynamic strain response has a tendency to magnify, attention should be paid to the potential prestress loss or other deterioration behaviors of the bridge.

Facile and Massive Aluminothermic Synthesis of Mayenite Electrides from Cost-Effective Oxide and Metal Precursors.

Subnanoporous mayenite electride [Ca24Al28O64]4+(O2-)2- x(e-)2 x (C12A7:e-) as the first room temperature-stable inorganic electride has attracted intensive attention because of its fascinating chemical, electrical, optical, and magnetic properties. However, it usually needs to be synthesized through a complicated multistep process involving high temperature (e.g., 1350 °C) precrystallization, severe reduction (e.g., 700-1300 °C for up to 240 h in Ca or Ti metal vapor atmosphere), and postpurification. Herein, a facile one-step aluminothermic synthesis method was developed for the massive production of C12A7:e- powders directly from a mixture of cost-effective CaO, Al2O3, and Al powders under much milder conditions (e.g., calcination at 1100 °C in flowing Ar for 8 h). By merely adjusting the amount of Al, the electron densities ( Ne) in the as-synthesized C12A7:e- can be optimized up to 1.23 × 1021 cm-3, covering the insulator-metal transition (MIT). The further mechanistic studies of this new aluminothermic synthesis process revealed that the Al performed dual-functional roles, which not only acted as an in situ reducing agent but also dramatically decreased the formation temperatures of the mayenite structure. After suitable Ru loading, the Ru/C12A7:e- catalyst from massively produced electride powder showed a promising preliminary performance of NH3 synthesis (2.8 mmol·g-1·h-1) under mild conditions (1 atm and 400 °C).

Fabrication of a Miniature Multi-Parameter Sensor Chip for Water Quality Assessment.

Water contamination is a main inducement of human diseases. It is an important step to monitor the water quality in the water distribution system. Due to the features of large size, high cost, and complicated structure of traditional water determination sensors and devices, it is difficult to realize real-time water monitoring on a large scale. In this paper, we present a multi-parameter sensor chip, which is miniature, low-cost, and robust, to detect the pH, conductivity, and temperature of water simultaneously. The sensor chip was fabricated using micro-electro-mechanical system (MEMS) techniques. Iridium oxide film was electrodeposited as the pH-sensing material. The atomic ratio of Ir(III) to Ir(IV) is about 1.38 according to the X-ray photoelectron spectroscopy (XPS) analysis. The pH sensing electrode showed super-Nernstian response (-67.60 mV/pH) and good linearity (R² = 0.9997), in the range of pH 2.22 to pH 11.81. KCl-agar and epoxy were used as the electrolyte layer and liquid junction for the solid-state reference electrode, respectively, and its potential stability in deionized water was 56 h. The conductivity cell exhibited a linear determination range from 21.43 µ S / cm to 1.99 mS / cm , and the electrode constant was 1.566 cm-1. Sensitivity of the temperature sensor was 5.46 Ω / ° C . The results indicate that the developed sensor chip has potential application in water quality measurements.

Mechanical assessment of arterial dissection in health and disease: Advancements and challenges.

Arterial dissection involves a complex series of coupled biomechanical events. The past two decades have witnessed great advances in the understanding of the intrinsic mechanism for dissection initiation, and hence in the development of novel therapeutic strategies for surgical repair. This is due in part to the profound advancements in characterizing emerging behaviors of dissection using state-of-the-art tools in experimental and computational biomechanics. In addition, researchers have identified the important role of the microstructure in determining the tissue׳s fracture modality during dissection propagation. In this review article, we highlight a variety of approaches in terms of biomechanical measurements, computational modeling and histological/microstructural analysis used to characterize a dissection that propagates in healthy and diseased arteries. Notable findings with quantitative mechanical data are reviewed. We conclude by discussing some unsolved problems that are of interest for future research.