Non-Destructive Characterization of Railway Materials and Components with Infrared Thermography Technique.

Infrared (IR) thermography technology is one of the leading non-destructive evaluation (NDE) techniques based on infrared detection. Infrared thermography, in particular, has the advantage of not only being used in non-contact mode but also provides full images, real-time inspection, and relatively fast results. These advantages make it possible to perform thermal imaging analysis of railway materials and/or components, such as brake disc simulation, monitoring of abnormal heat generation, and monitoring of temperature changes, during mechanical tests.

A Comparative Study of Fault Diagnosis for Train Door System: Traditional versus Deep Learning Approaches.

A fault diagnosis of a train door system is carried out using the motor current signal that operates the door. A test rig is prepared, in which various fault modes are examined by applying extreme conditions, as well as the natural and artificial wears of critical components. Two approaches are undertaken toward the fault classification for comparative purposes: one is the traditional feature-based method that requires several steps for the processing features such as signal segmentation, the extraction of time-domain features, selection by Fisher's discrimination, and K-nearest neighbor.

Bayesian Prediction of Pre-Stressed Concrete Bridge Deflection Using Finite Element Analysis.

Vertical deflection has been emphasized as an important safety indicator in the management of railway bridges. Therefore, various standards and studies have suggested physics-based models for predicting the time-dependent deflection of railway bridges. However, these approaches may be limited by model errors caused by uncertainties in various factors, such as material properties, creep coefficient, and temperature.

Author Correction: Synthesis of MgAC-FeO/TiO hybrid nanocomposites via sol-gel chemistry for water treatment by photo-Fenton and photocatalytic reactions.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Reduction of Using Metal Plates with the Influenced of Applied Low Current and Physical Barrier of Filter Layers.

Although metal contact is known to reduce bacterial growth, the effects of physical barriers and electricity need further investigation. This study examined the bacteria-reducing properties of copper and stainless-steel metal plates with an added electrical current and up to three filter layers on the growth of (bacteria) and MS2 bacteriophages (virus). When used with a stainless-steel plate, electricity increased bacteria reduction by 39.

Correlation of α/γ-FeO nanoparticles with the toxicity of particulate matter originating from subway tunnels in Seoul stations, Korea.

According to the increasing concern about particulate matter (PM) pollution at subway systems, particularly its potentially severe effects on human health, this study investigated the constituents, characteristics, and toxicity of PM collected at underground subway stations in Seoul, Korea. It was found that α/γ-FeO NPs, which are considered as thermal products derived from the brake-wheel-rail interface, were the main components of PM (57.6% and 48% of PM and PM, respectively).

Tensile Fracture Behavior and Characterization of Ceramic Matrix Composites.

Tensile fracture behavior of ceramic matrix composites (CMCs) was investigated using characterization tools. First, a high-speed infrared camera was used to monitor the surface temperature of the CMC specimen during mechanical testing. An infrared camera is a tool used to detect infrared (IR) radiation emitted from a specimen as a function of temperature, and it was used to analyze the temperature monitoring of specimen surface and fracture behavior during the tensile test.

A Practical Guide to Source and Receiver Locations for Surface Wave Transmission Measurements across a Surface-Breaking Crack in Plate Structures.

The main objectives of this study are to investigate the interference of multiple bottom reflected waves in the surface wave transmission (SWT) measurements in a plate and to propose a practical guide to source-and-receiver locations to obtain reliable and consistent SWT measurements in a plate. For these purposes, a series of numerical simulations, such as finite element modelling (FEM), are performed to investigate the variation of transmission coefficient of surface waves across a surface-breaking crack in various source-to-receiver configurations in plates. Main variables in this study include the crack depths (0, 10, 20, 30, 40 and 50 mm), plate thicknesses (150, 200, 300, 400 and 800 mm), source-to-crack distances (100, 150, 200, 250 and 300 mm) and receiver-to-crack distances.

Active Complexes on Engineered Crystal Facets of MnO-CeO and Scale-Up Demonstration on an Air Cleaner for Indoor Formaldehyde Removal.

Crystal facet-dominated surfaces determine the formation of surface-active complexes, and engineering specific facets is desirable for improving the catalytic activity of routine transition-metal oxides that often deactivate at low temperatures. Herein, MnO-CeO was synthetically administered to tailor the exposure of three major facets, and their distinct surface-active complexes concerning the formation and quantitative effects of oxygen vacancies, catalytically active zones, and active-site behaviors were unraveled. Compared with two other low-index facets {110} and {001}, MnO-CeO with exposed {111} facet showed higher activity for formaldehyde oxidation and CO selectivity.

Synthesis of MgAC-FeO/TiO hybrid nanocomposites via sol-gel chemistry for water treatment by photo-Fenton and photocatalytic reactions.

MgAC-FeO/TiO hybrid nanocomposites were synthesized in different ratios of MgAC-FeO and TiO precursor. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray fluorescence spectrometry (XRF), electron spin resonance spectrometry (ESR), Brunauer-Emmett-Teller (BET), photoluminescence (PL), and UV photoelectron spectroscopy (UPS) were used to characterize the nanocomposites. The increase of MgAC-FeO, in the hybrid nanocomposites' core-shell structure, led to the decrease of anatase TiO peaks, thus reducing the photo-Fenton and photocatalytic activities.

Sensor Fault Detection and Signal Restoration in Intelligent Vehicles.

This paper presents fault diagnosis logic and signal restoration algorithms for vehicle motion sensors. Because various sensors are equipped to realize automatic operation of the vehicle, defects in these sensors lead to severe safety issues. Therefore, an effective and reliable fault detection and recovery system should be developed.

Comb-structured triboelectric nanogenerators for multi-directional energy scavenging from human movements.

A triboelectric nanogenerator (TENG) is an emerging energy harvesting technology utilizing multi-directional, wasted mechanical energies stemming from vibrations, winds, waves, body movements, etc. In this study, we report a comb-structured TENG (CTENG) capable of effectively scavenging multi-directional motions from human movements, which include walking, jumping, and running. By attaching CTENG to a person's calf, we obtain a root-mean-square (RMS) power value of 5.

In Situ Intermediates Determination and Cytotoxicological Assessment in Catalytic Oxidation of Formaldehyde: Implications for Catalyst Design and Selectivity Enhancement under Ambient Conditions.

Formation and decay of formaldehyde oxides (CHOO) affect the complete oxidation of formaldehyde. However, the speciation and reactivity of CHOO are poorly understood because of its extremely fast kinetics and indirect measurements. Herein, three isomers of CHOO (i.

Measuring Acoustic Roughness of a Longitudinal Railhead Profile Using a Multi-Sensor Integration Technique.

It is necessary to measure accurately the rolling noise generated by the friction between wheels and rails in railway transport systems. Although many systems have recently been developed to measure the surface roughness of wheels and rails, there exist large deviations in measurements between each system whose measuring mechanism is based on a single sensor. To correct the structural problems in existing systems, we developed an automatic mobile measurement platform, named the Automatic Rail Checker (ARCer), which measures the acoustic roughness of a longitudinal railhead profile maintaining a constant speed.

Performance Evaluation of Precast Concrete Using Microwave Heating Form.

The purpose of this study is to evaluate the temperature distribution, strength development, porosity, scanning electron microscopy observation, shrinkage, and surface properties of concrete in order to apply microwave heat curing to the precast method and to analyze the CO₂ emissions and economic feasibility of microwave heat curing. The heating of a steel form by microwave heating enabled concrete to be efficiently cured at a temperature within a range of ±5 °C. After the curing, demolding strength could be cleared through the densification of the concrete by decreasing the porosity of the concrete.

An Energy-Based Unified Approach to Predict the Low-Cycle Fatigue Life of Type 316L Stainless Steel under Various Temperatures and Strain-Rates.

An energy-based low-cycle fatigue model was proposed for applications at a range of temperatures. An existing model was extended to the integrated approach, incorporating the simultaneous effects of strain rate and temperature. A favored material at high temperature, type 316L stainless steel, was selected in this study and its material characteristics were investigated.

Surface Functionalization of Plastic Surfaces with Non-Biofouling Agarose Film to Develop a Chip-Based Platform.

We chemically functionalized several plastic surfaces using an agarose film for applying a protein chip. The chip performance was affected by the surface energy of each plastic after oxygen-plasma cleaning; as a result, polystyrene and polyethylene terephthalate showed a higher signal-to-noise ratio than did polypropylene. We envision that this study will help to develop a way to build biochips.

Development of a magnetic hybrid filter to reduce PM10 in a subway platform.

This study investigated the reduction of particulate matter (PM) in a subway platform using self-developed magnetic hybrid filters (magnet-magnet (MM) and magnet-cascade (MC) filter). The magnetic hybrid filter systems were installed and operated in Jegi-dong subway station (J station) platform. The removal efficiency of PM (particular matter with aerodynamic diameter less than 10 μm) was evaluated according to various influencing factors such as the combination of filters, linear velocity, and operating conditions of trains.

Oxidation-Mediated, Zwitterionic Polydopamine Coatings for Marine Antifouling Applications.

We synthesized a zwitterionic dopamine derivative ( ZW-DOPA) containing both catechol and amine groups, and we demonstrated an excellent marine antifouling surface by controlling the oxidation of ZW-DOPA. The oxidation was mediated by the deprotonation of catechol or the addition of an oxidant (ammonium persulfate (AP) or sodium periodate (NaIO)). The oxidation and subsequent molecular transformation of ZW-DOPA was investigated over time by UV-vis spectroscopy.

Particulate Matter Exposure of Passengers at Bus Stations: A Review.

This review clarifies particulate matter (PM) pollution, including its levels, the factors affecting its distribution, and its health effects on passengers waiting at bus stations. The usual factors affecting the characteristics and composition of PM include industrial emissions and meteorological factors (temperature, humidity, wind speed, rain volume) as well as bus-station-related factors such as fuel combustion in vehicles, wear of vehicle components, cigarette smoking, and vehicle flow. Several studies have proven that bus stops can accumulate high PM levels, thereby elevating passengers' exposure to PM while waiting at bus stations, and leading to dire health outcomes such as cardiovascular disease (CVD), respiratory effects, and diabetes.

Recent Progress in Flexible Organic Thermoelectrics.

Environmental energy issues caused by the burning of fossil fuel such as coal, and petroleum, and the limited resources along with the increasing world population pose a world-wide challenge. Alternative energy sources including solar energy, wind energy, and biomass energy, have been suggested as practical and affordable solutions to future energy needs. Among energy conversion technologies, thermoelectric (TE) materials are considered one of the most potential candidates to play a crucial role in addressing today's global energy issues.

Manipulation of -/-Type Thermoelectric Thin Films through a Layer-by-Layer Assembled Carbonaceous Multilayer Structure.

Recently, with the miniaturization of electronic devices, problems with regard to the size and capacity of batteries have arisen. Energy harvesting is receiving significant attention to solve these problems. In particular, the thermoelectric generator (TEG) is being studied for its ability to harvest waste heat energy.

Surface Characterizations of Railway Electrical Wires Coated with Anti-Icing Mixtures of Ethylene Glycol or Glycerol with Tap Water.

Icing of railway contact wires in the cold climates of the USA, Canada, China, Japan, and South Korea can cause significant problems and delays in the operation schedules of electric-powered trains and subway cars. As anti-icing methods, manual de-icing, contact-wire thermal running, resistive-wire-heating de-icing, and chemical de-icing have all been explored and tested. Among them, environmentally friendly chemical de-icing based on the same concept as that of automobileengine antifreezer can be practically effective for application to contact wires at railcar depots.

Size-dependent characteristics of diurnal particle concentration variation in an underground subway tunnel.

Understanding characteristics of diurnal particle concentration variation in an underground subway tunnel is important to reduce subway passengers' exposure to high levels of toxic particle pollution. In this study, real-time particle monitoring for eight consecutive days was done at a shelter located in the middle of a one-way underground subway tunnel in Seoul, Republic of Korea, during the summer of 2015. Particle mass concentration was measured using a dust monitor and particle number concentration using an optical particle counter.