• Title/Summary/Keyword: smart materials

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Application of polymer, silica-fume and crushed rubber in the production of Pervious concrete

  • Li, Diyuan;Toghroli, Ali;Shariati, Mahdi;Sajedi, Fathollah;Bui, Dieu Tien;Kianmehr, Peiman;Mohamad, Edy Tonnizam;Khorami, Majid
    • Smart Structures and Systems
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    • v.23 no.2
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    • pp.207-214
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    • 2019
  • Achieving a pervious concrete (PC) with appropriate physical and mechanical properties used in pavement have been strongly investigated through the use of different materials specifically from the global waste materials of the populated areas. Discarded tires and the rubber tire particles have been currently manufactured as the recycled waste materials. In the current study, the combination of polymer, silica fume and rubber aggregates from rubber tire particles have been used to obtain an optimized PC resulting that the PC with silica fume, polymer and rubber aggregate replacement to mineral aggregate has greater compressive and flexural strength. The related flexural and compressive strength of the produced PC has been increased 31% and 18% compared to the mineral PC concrete, also, the impact resistance has been progressed 8% compared to the mineral aggregate PC and the permeability with Open Graded Fraction Course standard (OGFC). While the manufactured PC has significantly reduced the elasticity modulus of usual pervious concrete, the impact resistance has been remarkably improved.

Implementation of Real-time Integrated Platform for Producing Food Packaging Container

  • Kim, Chigon;Park, Jong-Youel;Park, Dea-Woo
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.1
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    • pp.194-200
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    • 2021
  • This study proposes a plan to construct an integrated platform that reduces manufacturing costs and efficiently produce by integrating the systems of main producers, production subcontractors, and raw material subcontractors for the production of food packaging containers. The production plan of food packaging containers and raw materials is established in real time between the main producers, production subcontractors, and raw material subcontractors in consideration of the demand characteristics of each product. It establishes basic information that all processes from the production planning stage to the forwarding stage of the product are linked to each other. The progress of each producer of interlinked processes is shared in real-time to improve productivity and quality of food packaging containers and raw materials and reduce manufacturing costs. By monitoring the system of the main producer and the production subcontractor in real time, the production of food packaging containers is performed in a timely manner, thereby improving productivity. The application of the plan-do-check-action (PDCA) process, which includes planning, execution, evaluation and improvement in the production operation processes of the main producer, production subcontractor and raw material subcontractor, enables improved production compliance rate. The contents of the main producers, production subcontractors, and raw material subcontractors are managed in real time, then a converged production management system is established through the platform proposed in this study to ensure timely supply and demand of raw materials without delay in ordering.

A Brief Review on Piezoelectrics-Based Paint Sensors (압전 기반 페인트 센서 기술 동향)

  • Hyoung-Su Han;Trang An Duong;Chang Won Ahn;Byeong Woo Kim;Jae-Shin Lee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.5
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    • pp.433-441
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    • 2023
  • Piezoelectric ceramics play an important role in electrical and electronic devices such as sensors, actuators, and microelectronic devices. However, traditional ceramics are difficult to be used in various process industries due to their high brittleness and low flexibility. Therefore, piezoelectric paint sensors have been designed for application to the curved surfaces of complicated structures. Furthermore, recently, significant attention has been focused on the development of paint sensors that can be used as structure health monitoring sensors for vibration, impact, and acoustic emission. Several studies have successfully demonstrated the possibility that smart paint sensors can take the place of traditional ceramic sensors. In this review, we briefly introduce the concept of the piezoelectric paint sensors and the expected application field as well as their preparation and history.

Characteristic analysis and condenser design of gas helium circulation system for zero-boil-off storage tank

  • Jangdon Kim;Youngjun Choi;Keuntae Lee;Jiho Park;Dongmin Kim;Seokho Kim
    • Progress in Superconductivity and Cryogenics
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    • v.25 no.4
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    • pp.65-69
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    • 2023
  • Hydrogen is an eco-friendly energy source and is being actively researched in various fields around the world, including mobility and aerospace. In order to effectively utilize hydrogen energy, it should be used in a liquid state with high energy storage density, but when hydrogen is stored in a liquid state, BOG (boil-off gas) is generated due to the temperature difference with the atmosphere. This should be re-condensed when considering storage efficiency and economy. In particular, large-capacity liquid hydrogen storage tank is required a gaseous helium circulation cooling system that cools by circulating cryogenic refrigerant due to the increase in heat intrusion from external air as the heat transfer area increases and the wide distribution of the gas layer inside the tank. In order to effectively apply the system, thermo-hydraulic analysis through process analysis is required. In this study, the condenser design and system characteristics of a gaseous helium circulation cooling system for BOG recondensation of a liquefied hydrogen storage tank were compared.

Foot Pressure Mat with Visual Notification for Recognizing and Correcting Foot Pressure Imbalance (시각적 알림이 있는 족저압매트 개발을 통한 족저압 불균형 인지와 즉각적인 교정)

  • Hanna Park;Bonhak Koo;Jinhee Park;Jooyong Kim
    • Journal of Fashion Business
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    • v.28 no.1
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    • pp.83-97
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    • 2024
  • A plantar pressure mat with visual notifications was developed to confirm whether individuals can effectively balance themselves and correct imbalances. The sensor-embedded mat was made with a commercial yoga mat, and was tested on seven working women in their 30s to determine plantar pressure distribution when standing and squatting, and if they could recognize and correct imbalances with visual feedback. The study found that visual notifications significantly changed the plantar pressure ratio of the forefoot and hindfoot, as well as the left and right foot plantar pressure ratio. Without notifications, the center of gravity was more concentrated in the rear foot than the forefoot in both standing and squatting positions. Visual notifications showed that the center of gravity, which was largely focused on the rear foot, was distributed to the forefoot, resulting in a more evenly distributed center of gravity throughout the sole. For the change in left and right plantar pressure, the weight that was largely loaded on the left side was distributed to the right foot through the visual notification mat, confirming a more balanced plantar pressure.

Development and Evaluation of Rack Type Piezoelectric Harvester for Smart Street Lamps Control (가로등 제어용 다층패드형 압전 하베스터의 개발 및 평가)

  • Kim, Chang-Il;Jeong, Young-Hun;Park, Woon Ik;Cho, Jeong-Ho;Jang, Yong-Ho;Choi, Beom-Jin;Park, Shin-Seo;Paik, Jong-Hoo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.11
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    • pp.696-701
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    • 2016
  • In this study, to increase output of road piezoelectric energy harvester, it was made into rack type in which many piezoelectric materials can be installed and load transfer device of the leverage type to transfer vehicle load was made. By paving it in the road, the output characteristics depending on vehicle load and speed were evaluated. Changing vehicle load, harvester output characteristics depending on speed changes were evaluated at the interval of 10 km/h from 10 km/h to 100 km/h. Also, by making a wireless switch and sending wireless signal with output of rack type harvester, whether to receive it was evaluated by distance. It was checked that all switches work up to front-to-back 100 m from harvester.

Wearable Resistive Strain Sensor Networked by Wireless Data Transfer System (무선 데이터 전송 시스템이 장착된 웨어러블 저항식 스트레인 센서)

  • Oh, Je-Heon;Lee, Sung-Ju;Shin, Hae-Rin;Kim, Seung-Rok;Yoo, Ju-Hyun;Park, Jin-Woo
    • Journal of the Microelectronics and Packaging Society
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    • v.25 no.3
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    • pp.43-47
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    • 2018
  • In this study, we fabricated transparent resistive strain sensor by embedding silver nanowire in polydimethylsiloxane (PDMS) substrate to sense the finger bending motion electrically. Using bluetooth as wireless data transfer system, strain data was transferred to computer and smart phone application enabling near field communication. Additionally, we made a program translating resistance change by finger motion strain to save images and confirmed that it worked at application and computer.

Selective NO2 Sensors Using MoS2-MoO2 Composite Yolk-shell Spheres

  • Jeong, Seong Yong;Choi, Seung Ho;Yoon, Ji-Wook;Won, Jong Min;Kang, Yun Chan;Park, Joon-Shik;Lee, Jong-Heun
    • Journal of Sensor Science and Technology
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    • v.24 no.3
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    • pp.151-154
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    • 2015
  • The gas sensing characteristic of $MoS_2-MoO_2$ composite yolk-shell spheres were investigated. $MoO_3$-carbon composite spheres were prepared by ultrasonic spray pyrolysis of aqueous droplets containing Mo-source and sucrose in nitrogen, which were converted into $MoO_3$ yolk-shell spheres by heat treatment at $400^{\circ}C$ in air. Subsequently, $MoS_2-MoO_2$ composite yolk-shell spheres were prepared by the partial sulfidation of $MoO_3$. The $MoS_2-MoO_2$ composite yolk-shell spheres showed relatively low and irreversible gas sensing characteristics at < $200^{\circ}C$. In contrast, the sensor showed high and reversible response (S=resistance ratio) to 5 ppm $NO_2$ (S=14.8) at $250^{\circ}C$ with low cross-responses (S=1.17-2.13) to other interference gases such as ethanol, CO, xylene, toluene, trimethylamine, $NH_3$, $H_2$, and HCHO. The $MoS_2-MoO_2$ composite yolk-shell spheres can be used as reliable sensors to detect $NO_2$ in a selective manner.

Effects of four novel root-end filling materials on the viability of periodontal ligament fibroblasts

  • Akbulut, Makbule Bilge;Arpaci, Pembegul Uyar;Eldeniz, Ayce Unverdi
    • Restorative Dentistry and Endodontics
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    • v.43 no.3
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    • pp.24.1-24.12
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    • 2018
  • Objectives: The aim of this in vitro study was to evaluate the biocompatibility of newly proposed root-end filling materials, Biodentine, Micro-Mega mineral trioxide aggregate (MM-MTA), polymethylmethacrylate (PMMA) bone cement, and Smart Dentin Replacement (SDR), in comparison with contemporary root-end filling materials, intermediate restorative material (IRM), Dyract compomer, ProRoot MTA (PMTA), and Vitrebond, using human periodontal ligament (hPDL) fibroblasts. Materials and Methods: Ten discs from each material were fabricated in sterile Teflon molds and 24-hour eluates were obtained from each root-end filling material in cell culture media after 1- or 3-day setting. hPDL fibroblasts were plated at a density of $5{\times}10^3/well$, and were incubated for 24 hours with 1:1, 1:2, 1:4, and 1:8 dilutions of eluates. Cell viability was evaluated by XTT assay. Data was statistically analysed. Apoptotic/necrotic activity of PDL cells exposed to material eluates was established by flow cytometry. Results: The Vitrebond and IRM were significantly more cytotoxic than the other root-end filling materials (p < 0.05). Those cells exposed to the Biodentine and Dyract compomer eluates showed the highest survival rates (p < 0.05), while the PMTA, MM-MTA, SDR, and PMMA groups exhibited similar cell viabilities. Three-day samples were more cytotoxic than 1-day samples (p < 0.05). Eluates from the cements at 1:1 dilution were significantly more cytotoxic (p < 0.05). Vitrebond induced cell necrosis as indicated by flow cytometry. Conclusions: This in vitro study demonstrated that Biodentine and Compomer were more biocompatible than the other root-end filling materials. Vitrebond eluate caused necrotic cell death.

Effect of Increased Oxygen Content due to Intensive Milling on Phase and Microstructural Development of Silicon Nitride

  • Kim, Hai-Doo;Ellen Y. Sun;Paul F. Becher;Kim, Hyo-Jong;Han, Byung-Dong;Park, Dong-Soo
    • Journal of the Korean Ceramic Society
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    • v.38 no.5
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    • pp.405-411
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    • 2001
  • Compacts of a mixture of fine $\alpha$-Si$_3$N$_4$powders, 6% $Y_2$O$_3$and 1% $Al_2$O$_3$were attrition milled time on phase and microstructural development in silicon nitride ceramics. The sintered surface and the interior showed different behaviors in phase and microstructral developments. Increased oxygen content with increased milling time of powder mixture leads to the formation of Si$_2$$N_2$O phase at temperatures as low as 155$0^{\circ}C$. Si$_2$$N_2$O is stable in the interior of the samples but unstable in the surface region of the specimen sintered at higher temperature. This results in a duplex structure where the interior consists of Si$_2$$N_2$O grains dispersed in $\beta$-Si$_3$N$_4$matrix and a surface which contains only $\beta$-Si$_3$N$_4$. The alpha to beta phase transformation and the microstructural development are shown to be influenced by the formation and decomposition of the Si$_2$$N_2$O.

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