A Simulation of Air Lasing Seeded by an External Wave in a Femtosecond Laser Filament.

Air lasers induced by femtosecond laser filaments play an important role in remote sensing applications. Few studies have been dedicated to the spatial distribution of external-seeded air laser radiation in the laser filament based on the numerical simulation method, which can pave the way to understanding the mechanism of the external-seeded air lasing process during filamentation. In this study, numerical simulations of the propagation of an air laser seeded by an external plane wave with a wavelength of 391 nm during femtosecond laser filamentation were performed.

Effect of Mud Powder on the Performance of Bridge Deck Leveling Concrete in a Seasonally Frozen Region.

Mud powders in aggregates are often found to cause deterioration of concrete properties. Based on a study of the mechanical properties of bridge deck leveling concrete (BDLC) containing different mud powders at various ages, the effects of mud powders on concrete durability were evaluated through rapid chloride permeability testing, freeze-thaw testing, and the coupling of salt solution and a freeze-thaw test. The properties of the interfacial transition zone (ITZ) were also investigated via microhardness testing.

Network-level pavement maintenance and rehabilitation decision-making with the optimized annual budget.

Maintenance and rehabilitation (M&R) is necessary to keep pavement networks in good condition. Due to the capital intensity, M&R funding is always insufficient. The annual budget, determining the available funding, is a critical criterion when planning M&R treatments.

Unraveling Spatiotemporal Transient Dynamics at the Nanoscale via Wavelet Transform-Based Kelvin Probe Force Microscopy.

Mechanistic probing of surface potential changes arising from dynamic charge transport is the key to understanding and engineering increasingly complex nanoscale materials and devices. Spatiotemporal averaging in conventional heterodyne detection-based Kelvin probe force microscopy (KPFM) inherently limits its time resolution, causing an irretrievable loss of transient response and higher-order harmonics. Addressing this, we report a wavelet transform (WT)-based methodology capable of quantifying the sub-ms charge dynamics and probing the elusive transient response.

RDD-YOLOv5: Road Defect Detection Algorithm with Self-Attention Based on Unmanned Aerial Vehicle Inspection.

Road defect detection is a crucial aspect of road maintenance projects, but traditional manual methods are time-consuming, labor-intensive, and lack accuracy. Leveraging deep learning frameworks for object detection offers a promising solution to these challenges. However, the complexity of backgrounds, low resolution, and similarity of cracks make detecting road cracks with high accuracy challenging.

Stress Monitoring of Segment Structure during the Construction of the Small-Diameter Shield Tunnel.

Segmental stress during the construction process plays a pivotal role in assessing the safety and quality of shield tunnels. Fiber Bragg grating (FBG) sensing technology has been proposed for tunnel segment stress monitoring. A laboratory test was conducted to validate the reliable strain measurement of FBG sensors.

Study on Thermal Stability and Fatigue Properties of SBS/CNT-Modified Asphalt Sealant.

Carbon nanotubes (CNTs) and styrene-butadiene-styrene (SBS) are used as reinforcing modifiers in asphalt sealants due to their excellent properties, which can effectively improve the internal structure of the sealant and enhance its mechanical properties. Based on this background, two SBS/CNT-modified asphalt sealants were identified and selected by the orthogonal experimental method and compared with two commercially available sealants. The softening point, flow value, multi-temperature frequency scan test, and multiple stress creep recovery test were used to study the high-temperature rheological properties and aging resistance of four types of sealants.

Freeze-Thaw Damage Mechanism Analysis of SBS Asphalt Mixture Containing Basalt Fiber and Lignocellulosic Fiber Based on Microscopic Void Characteristics.

Freeze-thaw effects pose the significant challenge to asphalt pavement durability, leading to various types of distress and deterioration. This study investigates the freeze-thaw damage mechanism of Styrene-Butadiene-Styrene (SBS) asphalt mixtures containing reinforcement fibers, specifically basalt fiber as well as lignocellulosic fiber, through a microscopic void characteristics analysis. This investigation aims to understand how the presence of basalt fiber as well as lignocellulosic fiber influences void characteristics for SBS asphalt mixtures during freeze-thaw cycles.

Molecular simulation on compatibility and mechanisms of SBS and PTW polymer modifiers in asphalt binder.

Context: Ultrathin overlays are preventive maintenance measures; the tensile and shear stresses generated inside a structural layer under vehicle load are greater than those of conventional thickness asphalt pavement. Therefore, asphalt binders must use high-viscosity and elasticity unique cementing materials to ensure stability. To investigate the modification mechanism of styrene-butadiene-styrene (SBS)/ethylene-butyl acrylate-glycidyl methacrylate copolymer (PTW) high-viscosity modified asphalt binder suitable for ultrathin overlays, the compatibility and molecular behavior of SBS/PTW high-viscosity modified asphalt binder were analyzed by the molecular dynamics (MD) method.

Uniform zinc-ion deposition regulated by thin sulfonated poly(ether ketone) layer for Stabilizing Zn anodes.

Aqueous zinc-ion batteries (AZIBs) have been getting lots of attention in the field of large scale energy storage owing to their low cost, large capacity and excellent safety. However, Zn anodes have serious dendritic growth and corrosion hydrogen evolution issues, which hinder their further application. Herein, a simple drop-coating technique was used to build a thin sulfate poly(ether ketone) (SPEEK) solid-electrolyte interphase (SEI) on the surface of the Zn anode to address these issues.

Critical safety management driver identification based upon temporal variation characteristics of driving behavior.

Identifying critical safety management drivers with high driver-level risks is essential for traffic safety improvement. Previous studies commonly evaluated driver-level risks based upon aggregated statistical characteristics (e.g.

Particle Counting Methods Based on Microfluidic Devices.

Particle counting serves as a pivotal constituent in diverse analytical domains, encompassing a broad spectrum of entities, ranging from blood cells and bacteria to viruses, droplets, bubbles, wear debris, and magnetic beads. Recent epochs have witnessed remarkable progressions in microfluidic chip technology, culminating in the proliferation and maturation of microfluidic chip-based particle counting methodologies. This paper undertakes a taxonomical elucidation of microfluidic chip-based particle counters based on the physical parameters they detect.

Assessing the dynamic resilience of Urban Rail Transit Networks during their evolution using a ridership-weighted network.

The assessment of the resilience of Urban Rail Transit Networks (URTNs) and the analysis of their evolutionary characteristics during network growth can help in the design of efficient, safe, and sustainable networks. However, there have been few studies regarding the change of resilience in long-term network development. As for the existing resilience studies, they rarely consider the entire cycle of accident occurrence and repair; furthermore, they ignore the changes in network transportation performance during emergencies.

Machine Learning-Enhanced Biomass Pressure Sensor with Embedded Wrinkle Structures Created by Surface Buckling.

Flexible piezoresistive sensors are core components of many wearable devices to detect deformation and motion. However, it is still a challenge to conveniently prepare high-precision sensors using natural materials and identify similar short vibration signals. In this study, inspired by microstructures of human skins, biomass flexible piezoresistive sensors were prepared by assembling two wrinkled surfaces of konjac glucomannan and k-carrageenan composite hydrogel.

Estimation for running time and energy losses due to unproductive stops at bus stations in urban-rural traffic corridors.

To provide data support for developing fixed-route DRT based on FRT to reduce operating costs inside base routes in urban-rural traffic corridors, this paper estimated running time and energy losses due to unproductive stops at bus stations in urban-rural traffic corridors. Firstly, 14 urban-rural bus routes without ticket sellers in Xi'an are selected to demonstrate the universality of unproductive stops at bus stations. Secondly, a model for estimating running time and energy losses based on the VT-CPFM model is developed.

The impact of non-driving related tasks on the development of driver sleepiness and takeover performances in prolonged automated driving.

Introduction: Vehicle automation is thought to improve road safety since numerous accidents are caused by human error. However, the lack of active involvement and monotonous driving environments due to automation may contribute to drivers' passive fatigue and sleepiness. Previous research indicated that non-driving related tasks (NDRTs) were beneficial in maintaining drivers' arousal levels but detrimental to takeover performance.

Deviation of peak hours for metro stations based on least square support vector machine.

The station-level ridership during the peak hour is one of the key indicators for the design of station size and relevant facilities. However, with the operation of metro system, it cannot be ignored that, in many cities, the station peak and the city peak may not be simultaneously occurred. As the current ridership forecasting methods use the city peak as the point of reference, stations with wide differences of ridership in between would experience disorders due to serious underestimates of passenger demand during the actual peak.

Interpretable ensemble imbalance learning strategies for the risk assessment of severe-low-level wind shear based on LiDAR and PIREPs.

The occurrence of severe low-level wind shear (S-LLWS) events in the vicinity of airport runways poses a significant threat to flight safety and exacerbates a burgeoning problem in civil aviation. Identifying the risk factors that contribute to occurrences of S-LLWS can facilitate the improvement of aviation safety. Despite the significant influence of S-LLWS on aviation safety, its occurrence is relatively infrequent in comparison to non-SLLWS incidents.

Frictional resistance calculation and jacking force prediction of rectangular pipe jacking.

In practical engineering, whilst estimating the jacking force of rectangular pipe jacking using an empirical formula, the results obtained from said formula deviate from reality and manifest inadequate engineering guidance. The equations governing the applied force during the installation of rectangular pipe jacking have been derived for various contact states involving the interaction between the pipe, slurry, and soil. The distinct stress conditions in the pipe jacking process as well as the shear-friction mechanism between the pipe and the surrounding soil have been taken into account.

Investigation of the Effects of Polyurethane-Modified Polycarboxylate at Ambient Temperature on the Characteristics of Cement with Supplementary Cementitious Materials.

Via radical polymerization, three polyurethane-modified polycarboxylate molecules of various comb topologies were synthesized. This study investigated the effects of varying types and concentrations of supplementary cementitious materials (SCMs) on the surface tension, flowability, and zeta potential of cement. An elevation in the molar ratio between isoamyl alcohol polyoxyethylene (TPEG) and acrylic acid (AA) from 1:1 to 5:1 reduced the surface tension of the polycarboxylate molecule from 47.

An Integrated Method for Tunnel Health Monitoring Data Analysis and Early Warning: Savitzky-Golay Smoothing and Wavelet Transform Denoising Processing.

A tunnel health monitoring (THM) system ensures safe operations and effective maintenance. However, how to effectively process and denoise several data collected by THM remains to be addressed, as well as safety early warning problems. Thus, an integrated method for Savitzky-Golay smoothing (SGS) and Wavelet Transform Denoising (WTD) was used to smooth data and filter noise, and the coefficient of the non-uniform variation method was proposed for early warning.

Evaluation and Improvement of Employee Performance with respect to Health, Safety, and Environment (HSE) Factors: A Case of Complex Transport Construction Project.

Risk control in complex transport construction is complicated due to the dangerous nature of high variation and unpredictability. Most of the current research analysis focuses on the health, safety, and environment (HSE) risk assessment and employee performance evaluation, which neglects the impact of HSE risks on employee performance. Consequently, this research develops a framework to evaluate employee performance and identify key factors affecting performance.

Experimental Study of the Shear Performance of Combined Concrete-ECC Beams without Web Reinforcement.

Background: Shear damage of beams is typically brittle damage that is significantly more detrimental than flexural damage.

Purpose: Based on the super-high toughness and good crack control ability of engineered cementitious composites (ECC), the shear performance of concrete-ECC beams was investigated by replacing a portion of the concrete in the tensile zone of reinforced concrete beams with ECC and employing high-strength reinforcing bars to design concrete-ECC beams. The purpose of this investigation is to elucidate and clarify the shear performance of concrete-ECC beams.

A Study of Molecular Dynamic Simulation and Experimental Performance of the Eucommia Ulmoides Gum-Modified Asphalt.

In recent years, eucommia ulmoides gum (EUG), also known as gutta-percha, has been extensively researched. Molecular dynamic simulations and experiments were used together to look at how well gutta-percha and asphalt work together and how gutta-percha-modified asphalt works. To investigate the gutta-percha and asphalt blending systems, the molecular models of asphalt and various dosages of gutta-percha-modified asphalt were set up using Materials Studio (MS), and the solubility parameters, intermolecular interaction energy, diffusion coefficient, and mechanical properties (including elastic modulus, bulk modulus, and shear modulus) of each system were calculated using molecular dynamic simulations at various temperatures.