Influences of Nanostructures of Sn and Ir for the Oxygen Evolution Reaction in Polymer Electrolyte Membrane Water Electrolysis

The influence of nanostructures and interaction of Sn and Ir in oxygen evolution catalysts in a polymer electrolyte membrane electrolyzer were investigated. For this aim, two synthesis methods, namely, the one-step solution combustion method and the precipitation-deposition method with sodium borohydride reduction, were evaluated to prepare...

Railway sleeper vibration measurement by train-borne laser Doppler vibrometer and its speed-dependent characteristics

A train-borne laser Doppler vibrometer (LDV) directly measures the dynamic response of railway track components from a moving train, which has the potential to complement existing train-borne technologies for railway track monitoring. This paper proposes a holistic methodology to characterize train-borne LDV measurements by combining computer...

Vertical dynamic measurements of a railway transition zone: a case study in Sweden

This study presents a measuring framework for railway transition zones using a case study on the Swedish line between Boden and Murjek. The final goal is to better understand the vertical dynamics of transition zones using hammer tests, falling weight measurements, and axle box acceleration (ABA) measurements. Frequency response functions ...

Measuring transfer functions of track structures in a test rig with laser Doppler vibrometer and accelerometers on a moving vehicle

A transfer function (TF) is an effective representation of the load-response relationship of railway track structures. To fill the gap in measuring track structure TFs over a wide frequency range from a moving vehicle, we develop a TF measurement system and the associated TF estimation methodology. Accelerometers are utilized to estimate the...

Numerical Study of Percolation and Seepage Behaviors in Ion-Adsorption-Type Rare Earth Ore Leaching Process

Ionic rare earth ore is a type of featured rare earth ore in China. Its mining process suffers from a long leaching cycle and considerable consumption of leaching agents. Improving mining efficiency requires a sound physical understanding of the leaching process. In this study, the CFD-based numerical model is used to analyze the physical...

A Self-Bias-Flip with Charge Recycle Interface Circuit with No External Energy Reservoir for Piezoelectric Energy Harvesting Array

This article presents a piezoelectric energy harvesting (PEH) interface circuit using a new self-bias-flip with the charge recycle (SBFR) technique without employing any additional energy reservoir. Traditional designs, including synchronous-switch harvesting on inductor (SSHI), synchronous-switch harvesting on capacitor (SSHC), synchronous...

A micro graphene high temperature sensor with a single Si₃N₄ protective layer

Temperature sensors are widely used in industrial production, national defense and military fields. The traditional temperature sensors normally operate in a limited temperature range no more than 200 °C, which cannot be used for extreme high temperature detections. In this paper, a thermal protection method for the sensing graphene membrane...

An Interpretable Method for Operational Modal Analysis in Time-Frequency Representation and Its Applications to Railway Sleepers

Operational modal analysis (OMA) enables the identification of modal characteristics under operational loads and conditions. Traditional frequency-domain methods cannot directly capture modal changes over time, while existing time-frequency representations are not sufficiently interpretable due to spurious modes and implicit parameter design....

Patching sulfur vacancies: A versatile approach for achieving ultrasensitive gas sensors based on transition metal dichalcogenides

Transition metal dichalcogenides (TMDCs) garner significant attention for their potential to create high-performance gas sensors. Despite their favorable properties such as tunable bandgap, high carrier mobility, and large surface-to-volume ratio, the performance of TMDCs devices is compromised by sulfur vacancies, which reduce carrier...

A Novel High-temperature Pressure Sensor Based on Graphene Coated by Si3N4

The high-temperature pressure sensors have wide applications in aerospace, petroleum, geothermal exploration, automotive electronics, and other fields. However, the traditional silicon-based pressure sensors are restricted to pressure measurement under 120~{\circ }\text{C} and cannot be satisfied to measure the pressure of various gases or...

A Self Bias-flip Piezoelectric Energy Harvester Array without External Energy Reservoirs achieving 488% Improvement with 4-Ratio Switched-PEH DC-DC Converter

With the advent of the lnternet-of-Things (1oT) era, sensor nodes are required in almost all fields to achieve a better interaction between humans and the environment. Piezoelectric energy harvester (PEH), which exhibits an equivalent electrical model of an AC current source /P in parallel with the inherent capacitor CP, is a promising...

A Simulation Study on Characterizing Transfer Functions of Railway Tracks Using Train-Borne Laser Doppler Vibrometer

Due to train load and aging, the dynamic properties of railway tracks degrade over time and deviate over space, which should be monitored to facilitate track maintenance decisions. A train-borne laser Doppler vibrometer (LDV) can directly measure track vibrations in response to the moving train load, which can be potentially applied to large...

Speckle noise reduction for structural vibration measurement with laser Doppler vibrometer on moving platform

Speckle noise is a major problem for structural vibration measurements with Laser Doppler vibrometer on moving platform (LDVom) due to its highly random, frequent, and broadband nature, especially at high speeds. This paper develops a new post-processing framework to reduce speckle noise based on a case study of LDVom measurements on railway...

China's transportation sector carbon dioxide emissions efficiency and its influencing factors based on the EBM DEA model with undesirable outputs and spatial Durbin model

The threat of global climate change has caused the international community to pay close attention to atmospheric levels of greenhouse gases such as carbon dioxide. Transportation sector carbon dioxide emissions efficiency (TSCDEE) is a key indicator used to prioritize sustainable development in the transportation sector. In this paper, the...

Tomographic SAR imaging with large elevation aperture: a P-band small UAV demonstration

Elevation resolution is an important indicator in tomographic SAR imaging as it represents the ability to discriminate closed targets in elevation. In general, the elevation resolution is proportional to the length of the elevation aperture. However, as the elevation aperture increases, the geometric consistency of the image will undesirably...

Can more accurate night-time remote sensing data simulate a more detailed population distribution?

Aging, shrinking cities, urban agglomerations and other new key terms continue to emerge when describing the large-scale population changes in various cities in mainland China. It is important to simulate the distribution of residential populations at a coarse scale to manage cities as a whole, and at a fine scale for policy making in...

Binding crystalline solids at low temperatures

Crystalline solids are solid materials whose constituent atoms, molecules, or ions are arranged in a highly regulated fashion. Due to lack of rotational freedom in their stacking, they have been known as fragile materials. Even though some efforts have been dedicated to bind or mend defects/cracks in amorphous materials like concrete or polymers...

Structural modulation and electronic structural features in the charge ordered state of La0.5Sr1.5MnO4