Experimental Investigation and Damage Identification of High-Pile Wharf Framed Bents under Horizontal Impact Loads.

This study investigates damage characteristics, dynamic structural performance changes, and quantitative damage assessment of high-pile wharf framed bents exposed to horizontal impact loads. Through extensive testing of wharf framed bents under such loads, a damage identification approach based on stiffness, natural vibration period, and acceleration data derived from experiments is presented. The findings reveal that under horizontal impact loads, framed bents initially exhibit tensile damage and leaning piles, followed by short straight piles. Additionally, structural damage results in a reduced self-oscillation frequency and an increased amplitude decay rate. Both stiffness-based and cycle-based damage indicators effectively track the cumulative damage progression of the structure. However, the cycle-based damage indicators demonstrate superior stability and accuracy, while acceleration-based indicators precisely identify the moment of damage mutation. This research contributes to enhancing local components, implementing damage identification methods, and advancing health monitoring practices in high-pile wharf projects, aligning with the standards of scientific publications in the field.

BMRC: A Bitmap-Based Maximum Range Counting Approach for Temporal Data in Sensor Monitoring Networks.

Due to the rapid development of the Internet of Things (IoT), many feasible deployments of sensor monitoring networks have been made to capture the events in physical world, such as human diseases, weather disasters and traffic accidents, which generate large-scale temporal data. Generally, the certain time interval that results in the highest incidence of a severe event has significance for society. For example, there exists an interval that covers the maximum number of people who have the same unusual symptoms, and knowing this interval can help doctors to locate the reason behind this phenomenon. As far as we know, there is no approach available for solving this problem efficiently. In this paper, we propose the Bitmap-based Maximum Range Counting (BMRC) approach for temporal data generated in sensor monitoring networks. Since sensor nodes can update their temporal data at high frequency, we present a scalable strategy to support the real-time insert and delete operations. The experimental results show that the BMRC outperforms the baseline algorithm in terms of efficiency.

[Determination of sodium cyclamate in Baijiu by pre-column derivatization-high performance liquid chromatography with fluorometric detection].

Sodium cyclamate in Baijiu is a key item in the China National Food Safety Supervision and Inspection Plan. A simple, economical, sensitive, and reliable method is urgently needed for routine analysis and internal quality control. A method based on high performance liquid chromatography with fluorescence detection (HPLC-FLD) was developed for the determination of sodium cyclamate in Baijiu by o-phthalaldehyde derivatization. First, the sodium cyclamate in the sample solution was converted into amino compounds using the desulfurization reaction under acidic conditions. Next, 400 g/L sodium hydroxide solution was added to the sample solution for neutralization. The amino compounds in the sample solution were then derivatized with o-phthalaldehyde to produce indole-substituted derivatives that are capable of producing fluorescence signals. Separation was carried out on a C18 column (250 mm×4.6 mm, 5 µm) in isocratic elution mode using a mobile phase consisting of acetonitrile and phosphate buffer. Finally, the eluate was monitored using a fluorescence detector, and an external standard method was used for quantification. A good linear relationship was obtained in the range of 0.1-2.0 mg/L, with correlation coefficients greater than 0.999. The average recoveries of sodium cyclamate spiked at levels of 0.1-1.0 mg/kg in Baijiu samples ranged from 90.7% to 100.9%, with relative standard deviations (RSDs) of 3.5%-5.6% (n=6). The limits of detection and quantification were 0.03 and 0.10 mg/kg, respectively. Nine Baijiu samples collected from the market were tested, and the results demonstrated that the contents of sodium cyclamate detected by the developed method were consistent with those obtained using the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method described in GB 5009.97-2016 (the third method). The proposed method is economical, sensitive, specific, and accurate; thus, it provides a basic approach for the determination of sodium cyclamate in Baijiu samples and has great potential for routine analysis in foodstuffs.

Noise Suppression of Nitrogen-Vacancy Magnetometer in Lock-In Detection Method by Using Common Mode Rejection.

Nitrogen-vacancy (NV) centers in diamonds are promising solid-state magnetic sensors with potential applications in power systems, geomagnetic navigation, and diamond NV color center current transformers, in which both high bandwidth and high magnetic field resolution are required. The wide bandwidth requirement often necessitates high laser power, but this induces significant laser fluctuation noise that affects the detection magnetic field resolution severely. Therefore, enhancement of the magnetic field resolution of wide-bandwidth NV center magnetic sensors is highly important because of the reciprocal effects of the bandwidth and magnetic field resolution. In this article, we develop a common mode rejection (CMR) model to eliminate the laser noise effectively. The simulation results show that the noise level of the light-detected magnetic resonance signal is significantly reduced by a factor of 6.2 after applying the CMR technique. After optimization of the laser power and modulation frequency parameters, the optimal system bandwidth was found to be 75 Hz. Simultaneously, the system's detection magnetic field resolution was enhanced significantly, increasing from 4.49 nT/Hz1/2 to 790.8 pT/Hz1/2, which represents an improvement of nearly 5.7 times. This wide-bandwidth, high-magnetic field resolution NV color center magnetic sensor will have applications including power systems, geomagnetic navigation, and diamond NV color center current transformers.

Pore size distributions and pore multifractal characteristics of medium and low-rank coals.

It is of great significance to study the porosity and permeability properties of medium and low-rank coal. The porosity and permeability in confining stress experiments were used to simulate the porosity and permeability variations of coal samples under different depth conditions. The pore structure of Baoqing coal samples is greatly affected by the confining pressure, and the pores and micro cracks are more easily compressed. Based on the experimental data of mercury intrusion porosimetry (MIP) and nitrogen adsorption (NA), the pore size distributions (PSDs) of medium and low-rank coals were studied. High mercury intrusion pressure would lead to coal matrix compression. Therefore, the pore volume calculated by MIP data was corrected by NA data. The PSDs characteristics of Jixi (JX) coal and Baoqing (BQ) coal samples are obtained from the revised pore volume, and the dominant pores of medium and low-rank coals are obtained. The results show that JX coal has higher spatial heterogeneity, connectivity and pore autocorrelation. Micro fractures have an influence on the autocorrelation and heterogeneity of coal samples, especially for BQ coal samples.