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An innovative bolt loosening detection method based on double-layer slotted circular patch antenna is proposed. By integrating the patch antenna with the bolt, the longitudinal length variation of the bolt can be transformed into a change in the air gap thickness of the antenna and cause the resonant frequency to vary. Thus, we can detect the bolt loosening through the resonant frequency shift of the double-layer circular patch antenna. Furthermore, the circular radiation patch of the antenna is slotted to increase the effective length of current flow, thus achieving the miniaturization of the antenna sensor for bolt loosening detection. The proposed double-layer slotted circular patch antenna sensor can be as small as a coin with a high sensing sensitivity of 626.57 MHz/mm, and it can be interrogated either wired or wirelessly. A series of simulations and experimental tests demonstrate the feasibility and effectiveness of the proposed antenna sensor for bolt loosening detection. The experimental results show that the relationship between the bolt preload and the antenna resonant frequency is relatively linear, and the resonant frequency of the antenna shifts 18 MHz for an M24 bolt from completely loosened to fully fastened. [ABSTRACT FROM AUTHOR]

In order to ensure the safety and preserve the value of historical buildings, inclination is an essential parameter during the continuous structural health monitoring process. However, the wire and price of a traditional sensor limit application. This paper proposes a low-cost inclination sensor based on a patch antenna with a reconfigurable water load. Only the water directly on the antenna is considered effective. The different volume of the effective water load, which is determined by the inclination of the attached surface, will affect the effective permittivity of the dielectric plate of the patch antenna, further causing a variation in the resonant frequency. Therefore, the proposed antenna sensor can monitor the inclination of the attached surface by interrogating the resonant frequency. The working mechanism is first clarified by theoretically investigating the relationship between the dielectric properties and the inclination of the covering medium. The antenna sensor is then simulated using High-Frequency Structure Simulator ver.15 (HFSS 15), which helps to determine geometric parameters and confirm accuracy and sensitivity. An experiment has been conducted based on the design verified in the simulation. The inclination detection shows a correlation coefficient of 0.9771 with a sensitivity of 7.92 MHz/°, indicating a potential for real application. [ABSTRACT FROM AUTHOR]

Seismic isolation technologies for large‐span structures have rapidly developed alongside the popularization of the seismic resilience concept. To produce a high‐efficiency isolation technology with lower energy dissipation demands, this paper proposes a novel inerter‐enabled isolator (IeI) and a tailored input energy reduction‐oriented design method. The inerter‐based damper within the IeI is developed by combining the dashpot, tuning spring, and two inerters to facilitate the optimization of inerter distribution. Assuming the large‐span structure remains linear, the overall seismic input energy of the large‐span structure with IeIs and its allocation in the superstructure and additional damping are quantified using stochastic energy analysis. The advantages of the IeI over the conventional linear viscous damper (LVD) isolator are elucidated through dimensionless parametric analysis. Based on the results of parametric analysis, an input energy reduction‐oriented design method is proposed for the IeI, along with an easy‐to‐follow diagram that helps with preliminary design in practical applications. The effectiveness of the IeI and the proposed design method is validated through a design case study of a benchmark large‐span structure. The results demonstrate that the IeI reduces the seismic response of large‐span structures by simultaneously employing the input energy reduction effect of grounded inerters with the damping‐enhancing effect of inerter‐based dampers. The proposed design method effectively balances the performance of controlling the large‐span structure and the isolator displacement. Under consistent control performance and isolator displacement constraints, the IeI requires much less damping coefficient and energy dissipation capacity than the conventional LVD isolator. Moreover, leveraging the damping enhancement and input energy reduction effects, the IeI achieves comparable control performance to the conventional LVD isolator, even under stricter isolator displacement constraints. [ABSTRACT FROM AUTHOR]

This article presents a novel passive patch antenna sensor for simultaneous crack and temperature sensing, and the antenna sensor has the ability of temperature self-compensation. The passive patch antenna sensor consists of an underlying patch and an overlapping sub-patch. The off-center feeding activates resonant modes in both transverse and longitudinal directions. The resonant frequency shift in transverse direction is used for environmental temperature sensing, while the structural crack width can be sensed by the longitudinal resonant frequency shift after temperature compensation. Furthermore, the unstressed design of the antenna can also eliminate the issue of incomplete strain transfer ratios. In this article, the relationships between the antenna resonant frequencies, the environmental temperature, and the structural crack width were studied. Simulations were conducted to determine the optimal off-center fed distance of the patch antenna sensor. Furthermore, a series of experimental tests were also conducted, where the passive patch antenna was fabricated and installed on the concrete components as well as an actual building. Continuous monitoring was performed for several days to test the temperature sensing ability of the passive patch antenna, and the sensed crack width after temperature compensation was compared with the actual results. The results of these experiments demonstrate the feasibility of using the passive patch antenna for simultaneous temperature and crack sensing. [ABSTRACT FROM AUTHOR]

An innovative cable-bracing inerter system (CBIS) has been proposed and shown to be effective in mitigating the structural response under dynamic excitation. The CBIS comprises an inerter element, an eddy current damping element, and a pair of tension-only cables that can transfer the story drift to rotating flywheels. To further investigate the characteristics of the CBIS, a system identification approach based on an adaptive extended Kalman filter (AEKF) and a recursive least-squares (RLS) algorithm is proposed. Depending on the CBIS model's availability, the proposed approach uses two strategies: the AEKF identifies the parameters of the structure and the CBIS when the model is specific; alternatively, when the model is unspecific, the KF combined with an RLS algorithm identifies the restoring force generated by the CBIS as an unknown fictitious input. In addition, the AEKF incorporates a time-variant fading factor to track the target adaptively. The proposed approach is validated through free vibration and shaking table tests, demonstrating the accuracy in identifying structural parameters and restoring force provided by the CBIS. The identification process involves two stages: initially, the AEKF identifies the parameters of the bare structure without the CBIS, followed by a dual strategy using either AEKF or KF-RLS for identifying the parameters of the CBIS or its restoring force, respectively. The findings also verify the feasibility and validity of the mechanical model and operating principle of the CBIS, thereby contributing to the advancement and application of the CBIS in future studies. [ABSTRACT FROM AUTHOR]

Objective To investigate the mechanism of Qiangxin Decoction treating chronic heart failure(CHF) by regulating miR-125b-5p and thus inhibiting the expression of nuclear factor-κB (NF-κB)-mediated inflammatory factors in order to protect the cardiovascular endothelial progenitor cells. Methods According to the random number table method, 42 SPF-grade SD rats were divided into the control group, the model group, the Qiangxin Decoction low-dose group (7.45 g/kg), the Qiangxin Decoction medium-dose group (14.90 g/kg), the Qiangxin Decoction high-dose group (29.80 g/kg), and the sacubitril valsartan group (10.42 mg/kg), with 7 rats in each group. Except for the control group, the CHF model was established by ligating the left anterior descending branch of the coronary artery in each group. Two days after modeling, the rats were treated with the corresponding drugs by gavage for 28 days. Cardiac function indexes, including left ventricular end-diastolic internal diameter (LVEDd), left ventricular end-systolic internal diameters (LVEDs), and left ventricular ejection fraction (LVEF), were examined by cardiac ultrasound examination, and the pathological changes in the myocardial tissue of the left ventricle of the rats were observed by HE staining. Myocardial fibrosis was observed in each group by Masson staining. Fluorescence in situ hybridization (FISH) was performed to determine the expression of miR-125b-5p in endothelial progenitor cells of the left ventricular myocardial tissue. The protein expressions of brain-derived neurotrophic factor (BDNF), NF-κB p65 and p-NF-κB p65 in the left ventricular myocardial tissue were detected by Western blotting. Enzyme-linked immunosorbent assay was used to detect the expression of inflammatory factor tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6. Results Compared with the control group, LVEDd and LVEDs were elevated and LVEF was reduced in the model group; the pathological damage of myocardial tissue was severe with abnormal changes in the tissue structure, striated muscle became fuzzy, and cardiomyocytes were disordered in their arrangement and partially denatured and necrotic; blue collagen fibers and mucus deposition in the myocardial tissues were increased; the average optical density of miR-125b-5p was increased in the left ventricular myocardial tissue; the protein expression of BDNF was decreased, and the ratio of p-NF-κB p65/NF-κB p65 was increased; the contents of TNF-α, IL-1β, and IL-6 were significantly increased (P<0.05). Compared with the model group, LVEDd and LVEDs were reduced, and LVEF was increased in the Qiangxin Decoction medium-, high-dose groups and the sacubitril valsartan group; the pathological damage of myocardial tissues in the left ventricle was improved, with clear striated muscle, neat and orderly arrangement of cardiomyocytes, and reduction of cellular necrosis; blue collagen fibers and mucus deposition were reduced, and myocardial fibrosis was significantly reduced; the average optical density of miR-125b-5p in the left ventricular myocardial tissue was significantly reduced; the protein expression of BDNF was increased, and the ratio of p-NF-κB p65/NF-κB p65 was reduced; the contents of TNF-α, IL-1β, and IL-6 were significantly reduced (P<0.05). Conclusion Qiangxin Decoction can reduce miR-125b-5p expression, inhibit the activation of NF-κB pathway, reduce the expression of the pro-inflammatory factors TNF-α, IL-1β, and IL-6, attenuate the myocardial inflammatory response, pathological injury and reduce myocardial fibrosis, ultimately protect the cardiovascular endothelium, and improve cardiac function to treat CHF. [ABSTRACT FROM AUTHOR]

The south building of Huadong Hospital is a well-known historic building in Shanghai, China. In August 2021, the building was lifted by 1.30 m to correct the subsidence caused by long-term use and to expand the usable space of the building. To ensure structural safety during uplifting of the historic building, a structural health monitoring system is devised to monitor the overall status of the structure and the state of critical components. The structural health monitoring system comprises sensor, data acquisition, and data management systems. The content that is monitored includes vertical displacement, horizontal displacement, inclination, differential settlement, cracks, strains, and acceleration. The overview and uplifting scheme of the historic building are first introduced. The monitoring system's design and sensor installation are then thoroughly discussed, followed by monitoring data analysis to investigate the state of the structure before and after uplifting. Furthermore, a structural safety assessment based on multisource monitoring data and neural networks is conducted. Huadong Hospital's south building is currently the largest uplifted historic building in terms of construction area in China. The building's structural health monitoring system played an exemplary and promoting role in structural health monitoring during uplifting of historic buildings, and it also has referential significance for similar engineering projects. [ABSTRACT FROM AUTHOR]