Lab- and pilot-scale wet scrubber study on the redox-mediated simultaneous removal of NO and SO using a CaCO-based slurry with KI as a redox catalyst.

This study presents a novel approach that integrates ozone-driven chemical oxidation to convert NO into soluble NO, followed by the simultaneous absorption of NO and SO into a CaCO-based slurry using the redox catalyst potassium iodide (KI). Using cyclic voltammetry, we demonstrate the redox properties of the I/2I couple, which facilitates NO reduction into soluble NO and catalyst regeneration through sulfite (SO)-driven reduction, thus establishing a closed catalytic cycle within the components of flue gas. In lab-scale wet-scrubbing tests, we explore the effect of various operational parameters (i.

Development of Maximum Residual Stress Prediction Technique for Shot-Peened Specimen Using Rayleigh Wave Dispersion Data Based on Convolutional Neural Network.

Shot peening is a surface treatment process that improves the fatigue life of a material and suppresses cracks by generating residual stress on the surface. The injected small shots create a compressive residual stress layer on the material's surface. Maximum compressive residual stress occurs at a certain depth, and tensile residual stress gradually occurs as the depth increases.

Strategies for Effective Management of Indoor Air Quality in a Kindergarten: CO and Fine Particulate Matter Concentrations.

The educational and play-related activities of children proceed mainly indoors in a kindergarten. High concentrations of indoor PM and CO have been linked to various harmful effects on children, considerably impacting their educational outcomes in kindergarten. In this study, we explore different scenarios involving the operation of mechanical ventilation systems and air purifiers in kindergartens.

The Effectiveness of a Mechanical Ventilation System for Indoor PM in Residential Houses.

The mechanical ventilation systems used in houses are designed to reduce carbon dioxide emissions while minimizing the energy loss resulting from ventilation. However, the increase in indoor fine particulate (PM) concentration because of external PM influx through the ventilation system poses a problem. Here, we analyzed the changes in indoor PM concentration, distinguishing between cases of high and low outdoor PM concentrations and considering the efficiency of the filters used in residential mechanical ventilation systems.

Nondestructive Evaluation of Residual Stress in Shot Peened Inconel Using Ultrasonic Minimum Reflection Measurement.

Shot peening is a process wherein the surface of a material is impacted by small, spherical metal shots at high velocity to create residual stresses. Nickel-based superalloy is a material with high strength and hardness along with excellent corrosion and fatigue resistance, and it is therefore used in nuclear power plants and aerospace applications. The application of shot peening to INCONEL, a nickel-based superalloy, has been actively researched, and the measurement of residual stresses has been studied as well.

Prediction of indoor PM concentrations and reduction strategies for cooking events through various IAQ management methods in an apartment of South Korea.

Indoor PM in apartments must be effectively managed to minimize adverse impacts on human health. Cooking is the one of the main PM sources in apartments, and indoor air quality (IAQ) management methods (natural ventilation, mechanical ventilations, range hoods, and air purifiers) are typically used to reduce PM generated during cooking. For effective control of indoor PM , prediction of PM reduction for various IAQ management methods is necessary.

Improvement of an In-Duct Two-Stage Electrostatic Precipitator via Diffusion Charging.

An in-duct two-stage electrostatic precipitator (ESP) improved by ion diffusion effect was studied. We increased the collection efficiency of a two-stage electrostatic precipitator without additional energy input by adjusting the space arrangement of the charger and the collector, which increased the particle diffusion charging time. The collection efficiency and the particle charge were systematically investigated according to the occurrence of diffusion charging and electric field charging in the charger as generated by the negative ions.

Development of On-Demand Antiviral Electrostatic Precipitators with Electrothermal-Based Antiviral Surfaces against Airborne Virus Particles.

Particulate matter, including airborne pathogens, is of particular concern because it can cause the spread of diseases through aerosol transmission. In this study, a new concept is proposed: on-demand antiviral electrostatic precipitators (ESPs) with electrothermal-based antiviral surfaces. We applied electrothermal-based antiviral surfaces to air-purifying applications and demonstrated that the proposed method is effective with regard to collecting airborne virus particles on collection plates in a two-stage ESP.

Ultrasonic device developed for non-invasive moxibustion therapy.

Background: Recently, some adverse effects of moxibustion has been reported such as burns, smoke, allergies, and so on. To overcome the adverse effects of traditional moxibustion, an ultrasonic moxibustion device (UMD) was designed, simulated, fabricated, and tested. The objective of this study is to provide detailed information about the main design parameters, simulation outcome, and performance-test results.

Propagation and Attenuation Characteristics of an Ultrasonic Beam in Dissimilar-Metal Welds.

Ultrasonic inspection of welds joining dissimilar metals in nuclear power plants has proven to be a challenge, because the ultrasonic waves are subject to diffraction, distortion, scattering, and noise. These perturbations are due to their interactions with coarse-grained microstructures having anisotropic and heterogeneous metallurgical properties that can promote ultrasonic attenuation. In this paper, to improve the reliability of ultrasonic testing for dissimilar-metal welds (DMWs), ultrasonic beam characteristics for DMWs with a buttering layer were investigated in order to analyze the beam distortion phenomenon caused by inhomogeneous anisotropic properties and coarse grains.

Convolutional neural network for ultrasonic weldment flaw classification in noisy conditions.

Ultrasonic flaw classification in weldment is an active area of research and many artificial intelligence approaches have been applied to automate this process. However, in the industrial applications, the ultrasonic flaw signals are not noise free and automatic intelligent defect classification algorithms show relatively low classification performance. In addition, most of the algorithms require some statistical or signal processing techniques to extract some features from signals in order to make classification easier.

Nonlinear ultrasonic characterization of early degradation of fatigued Al6061-T6 with harmonic generation technique.

In this paper, a third harmonic was used to investigate microstructural changes in Al6061-T6 due to different fatigue cycles and a relationship between fatigue cycle and third order nonlinearity has been observed. Piezoelectric measurement harmonic generation technique was applied for the specimens with 0%, 55%, 75% and 85% fatigue cycles, respectively. The results shows that the third order harmonics gradually increased up to 55% and rapidly decreased after wards, it was attributed to the behavior of dislocation, dislocation-precipitation interaction and voids with increasing fatigue cycle.

Novel electrostatic precipitator using unipolar soft X-ray charger for removing fine particles: Application to a dry de-NOX process.

The novel electrostatic precipitator (ESP), consisting of a soft X-ray charger and a collection part, was demonstrated and applied to a dry de-NOX process to evaluate its performance in by-product particle removal. NOX gas was oxidized by ozone (O3) and neutralized by ammonia (NH3) sequentially, and finally converted to an ammonium nitrate (NH4NO3) aerosol with ∼ 100-nm peak particle diameter. The unipolar soft X-ray charger was introduced for charging the by-product particles in this dry de-NOX process.

Delayed detection of clinically significant posterior cruciate ligament injury after peri-articular fracture around the knee of 448 patients.

Background: The purpose of this study was to report the frequency with which posterior cruciate ligament (PCL) injuries occurred in combination with peri-articular fractures around the knee, and to determine the frequency with which the detection of these PCL injuries was delayed (i.e., detected in an outpatient clinic after fracture treatment).

Integration of a nonmetallic electrostatic precipitator and a wet scrubber for improved removal of particles and corrosive gas cleaning in semiconductor manufacturing industries.

To remove particles in corrosive gases generated by semiconductor industries, we have developed a novel non-metallic, two-stage electrostatic precipitator (ESP). Carbon brush electrodes and grounded carbon fiber-reinforced polymer (CFRP) form the ionization stage, and polyvinyl chloride collection plates are used in the collection stage of the ESP The collection performance of the ESP downstream of a wet scrubber was evaluated with KC1, silica, and mist particles (0.01-10 pm), changing design and operation parameters such as the ESP length, voltage, and flow rate.

Fine particle removal performance of a two-stage wet electrostatic precipitator using a nonmetallic pre-charger.

A novel two-stage wet electrostatic precipitator (ESP) has been developed using a carbon brush pre-charger and collection plates with a thin water film. The electrical and particle collection performance was evaluated for submicrometer particles smaller than 0.01- 0.

Effect of an air cleaner with electrostatic filter on the removal of airborne house dust mite allergens.

Purpose: The effects of air cleaners on the removal of airborne indoor allergens, especially house dust mites (HDM), are still controversial. The objective of this study is to evaluate the effect of an air cleaner with an electrostatic filter on the removal of airborne mite allergens.

Materials And Methods: A dried HDM culture medium that contained mite body particles and excretions was dispersed in a chamber equipped with an electrostatic air cleaner.

Fine particle collection of an electrostatic precipitator in CO2-rich gas conditions for oxy-fuel combustion.

The collection of particles in CO(2)-enriched environments has long been important for the capture of CO(2) in order to clean gases via oxy-fuel combustion. We here report on the collection characteristics of fine and ultrafine particles using an electrostatic precipitator (ESP) in a CO(2)-enriched atmosphere. In order to understand the characteristics of particle collection in CO(2)-rich gas mixtures, the ionic properties of a CO(2)-enriched atmosphere was also investigated.

Evaluation of CVD diamond coating layer using leaky Rayleigh wave.

In the present study, the possibility of using leaky Rayleigh waves as a nondestructive tool for the evaluation of CVD diamond coating layer is explored experimentally. For this purpose, a set of CVD diamond coated specimens are prepared and the leaky Rayleigh waves are measured in an immersion, pulse-echo setup. For the proper analysis of the acquired signals we propose a novel signal analysis approach, namely the "time trace angular scan (TTAS)" image.

An ultrasonic measurement model using a multi-Gaussian beam model for a rectangular transducer.

To date, ultrasonic measurement models have primarily treated systems where circular transducers are used. Recently, however, a highly efficient ultrasonic beam model for a rectangular transducer has also become available where the transducer is represented as a superposition of a relatively few Gaussian beams. Thus, using the multi-Gaussian beams, we developed ultrasonic measurement models for systems where a rectangular transducer is employed.

Characterization of TiN coating layers using ultrasonic backward radiation.

Since ceramic layers coated on machinery components inevitably experience the changes in their properties it is necessary to evaluate the characteristics of ceramic coating layers nondestructively for the reliable use of coated components and the remaining life prediction. To address such a need, in the present study, the ultrasonic backward radiation technique is applied to examine the very thin TiN ceramic layers coated on AISI 1045 steel or austenitic 304 steel substrate. Specifically, the ultrasonic backward radiation profiles have been measured with variations in specimen preparation conditions such as coating layer thickness and sliding loading.

Generation of the basis sets for multi-Gaussian ultrasonic beam models--an overview.

By using a small number of Gaussian basis functions, one can synthesize the wave fields radiated from planar and focused piston transducers in the form of a superposition of Gaussian beams. Since Gaussian beams can be transmitted through complex geometries and media, such multi-Gaussian beam models have become powerful simulation tools. In previous studies the basis function expansion coefficients of multi-Gaussian beam models have been obtained by both spatial domain and k-space domain methods.

Comparison of modeling approaches to ultrasonic testing at near critical angles.

Modeling of ultrasonic testing has been paid a great attention in nondestructive evaluation community recently since it can provide thorough understanding of underlying physics of ultrasonic testing. As a result, there have been developed various modeling approaches up to now. Especially, many practical models have been developed based on either the multi-Gaussian beam or the Rayleigh-Sommerfeld integral.