• Title/Summary/Keyword: Metal & Plastic

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Storage Trial of Preliminary Processed Peach (복숭아 일차가공품(一次加工品)의 저장성(貯藏性)에 관한 연구(硏究))

  • Lee, Dong-Sun;Koo, Young-Jo;Shin, Dong-Hwa;Thorpe, Roy H.
    • Korean Journal of Food Science and Technology
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    • v.13 no.3
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    • pp.219-226
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    • 1981
  • To enable off-season peach canning, peaches were halved and processed into solid packs. Following variables were compared in relation to storage stability of solid packs. First as pretreatment-dipping in citric and ascorbic solution after lye peeling; second as pasturization in pouch and hot fill process; third as packaging method-2 ply(PET/PE) and 3 ply(PET/Al/PE) plastic film pouch and metal container; fourth as storage condition $-20^{\circ}C\;and\;-5^{\circ}C$. After 25 weeks storage test, all peaches in different packs were processed into canned peaches just like commercial products, and then quality was organoleptically evaluated from the viewpoint of processing and storage variable of solid packs. The results are follows; 1. Ascorbic acid dipping in 3 ply pouch and citric acid dipping in 2 ply pouch had better quality retention effect than any other pretreatments in respective packing. 2. Pasteurization method gave great effect on the color and texture of the solid pack during storage, but not on the quality of the final canned peach. 3. Can and 3 ply packing were better than 2 ply pouch in storage of solid pack and quality of final canned peach. 4. The $5^{\circ}C$ storage gave better quality than $20^{\circ}C$.

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In-vitro study on the accuracy of a simple-design CT-guided stent for dental implants

  • Huh, Young-June;Choi, Bo-Ram;Huh, Kyung-Hoe;Yi, Won-Jin;Heo, Min-Suk;Lee, Sam-Sun;Choi, Soon-Chul
    • Imaging Science in Dentistry
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    • v.42 no.3
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    • pp.139-146
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    • 2012
  • Purpose: An individual surgical stent fabricated from computed tomography (CT) data, called a CT-guided stent, would be useful for accurate installation of implants. The purpose of the present study was to introduce a newly developed CT-guided stent with a simple design and evaluate the accuracy of the stent placement. Materials and Methods: A resin template was fabricated from a hog mandible and a specially designed plastic plate, with 4 metal balls inserted in it for radiographic recognition, was attached to the occlusal surface of the template. With the surgical stent applied, CT images were taken, and virtual implants were placed using software. The spatial positions of the virtually positioned implants were acquired and implant guiding holes were drilled into the surgical stent using a specially designed 5-axis drilling machine. The surgical stent was placed on the mandible and CT images were taken again. The discrepancy between the central axis of the drilled holes on the second CT images and the virtually installed implants on the first CT images was evaluated. Results: The deviation of the entry point and angulation of the central axis in the reference plane were $0.47{\pm}0.27$ mm, $0.57{\pm}0.23$ mm, and $0.64{\pm}0.16^{\circ}$, $0.57{\pm}0.15^{\circ}$, respectively. However, for the two different angulations in each group, the $20^{\circ}$ angulation showed a greater error in the deviation of the entry point than did the $10^{\circ}$ angulation. Conclusion: The CT-guided template proposed in this study was highly accurate. It could replace existing implant guide systems to reduce costs and effort.

On the Development of Bonded Joints for Modular FRP Hulls using Moulding-In Concept (모듈방식 FRP 선체를 위한 Moulding-In 개념 기반의 접합 이음부 개발에 관한 연구)

  • Jeong, Han Koo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.6
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    • pp.531-539
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    • 2017
  • This paper deals with the development of bonded joints for fibre reinforced plastic (FRP) hull structures using moulding-in concept. Focus is placed on bonded in-plane connections between two adjacent panels that could form the boundaries of hull structural module. Traditional construction in FRP hull structures requires the construction of a mould, usually from steel or aluminium. In this construction the FRP materials are laid in the mould, and resin is saturated, and then the structural member is cured. This is expensive since it involves the fabrication of metal hull mould for every different hull type, which is sacrificed after the production of the FRP ship. One way of encouraging greater use of FRP in ship construction is to investigate the possible construction of FRP hull structures in a similar manner to metallic ships, that is in terms of blocks or modules. Such a manner of construction would eliminate the need for expensive hull moulds permitting greater flexibility in the construction of FRP ships. The main issue then would be the design and construction of adequate bonded connections between adjacent panels. To fulfill this object, the simplified and automated way of manufacturing joint edge shapes for bonded joints is developed, and their structural assessment is performed in both experimentally and numerically.

The Result of Ventilating Bronchoscopy for the Air Way Foreign Bodies (Ventilating bronchoscopy로 치유시도된 기도이물의 치료성과)

  • 우훈영;고건성;이희배;윤태현;안회영;백만기
    • Proceedings of the KOR-BRONCHOESO Conference
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    • 1978.06a
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    • pp.4.3-5
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    • 1978
  • The foreign bodies in air way require the emergent managements in the otolaryngolagic field, and if the diagnosis and treatment were delayed, unexperted catastrophic situations may occur. The authors had analysed the airway foreign bodies of 50 cases which had been ventilating bronchoscopy. 1. In sex distribution, male to female ratio was 2.8 : 1. 2. In the age incidence, 58% were 1∼5 yrs. 3. Frequent symptoms, were coughing (68%), dyspnea (52%) and cyanosis (18%) in the oder. 4. The significant foreign body histories were noticed in 33 cases (66%). The initial misdignosis were 28%, and af which 57.1% were URI 5. In auscultation, decreased breathing sounds were noticed in 46%, wheezing were 24% and 26% were with in normal limit. 6, In duration af lodgement, 68% were removed within 24 hours. 7. Tracheostomy were performed in 24%, and foreign bodies were removed by ventilating bronchoscope in 72%. 8. The foreign bodies were vegetable (46%), metal (28%), plastic (18%) and fish bone (8%). 9. The prevalent site of foreign body were right main bronchus, left main bronchus, and trachea in the order mentioned.

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Evaluation of Beach Pollution by Aquaculture Styrofoam Buoys in Tongyeong, Korea (양식장 스티로폼 부자쓰레기로 인한 통영 해변의 오염 평가)

  • Hong, Su Yeon;Lee, Chan Won;Hong, Sunwook;Lee, Jongmyoung;Jang, Yong Chang
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.17 no.2
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    • pp.104-115
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    • 2014
  • Abundance and composition of marine debris on 13 beaches of Tongyeong City, South Korea were surveyed in 2013 Autumn. The average quantity of macro debris (>25 mm) was about 30 particle/$m^2$ and that of micro debris (1 mm-25 mm) was about 26,971 particle/$m^2$. This is a very high level compared with other areas of South Korea and the other countries. Among the 7 material types of debris (styrofoam, hard plastic, fiber, metal, glass, wood and others), styrofoam composed a large portion: 75% of macro debris and 98% of micro debris. And among the 'whole' styrofoam debris items whose original volume is remained more than 50%, styrofoam buoy debris composed 93%. This result suggests that the beaches surveyed are seriously contaminated by marine debris, and most of its sources are aquaculture styrofoam buoys. Management of styrofoam buoy debris used for oyster aquaculture in Tongyeong City is important not only for Tongyeong city, but also for other areas, because Tongyeong city hosts the biggest number of oyster aquaculture areas in South Korea.

Characteristics of Marine Litters Distribution on the Sea-bed of the East China Sea (동중국해의 해저 폐기물 분포특성)

  • Jeong, Sun-Beom;Lee, Dae-In;Cho, Hyeon-Seo;Kim, Young-Joo
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.8 no.4
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    • pp.220-226
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    • 2005
  • This study evaluated the composition and distribution of marine litters on the sea-bed of the East China Sea. Surveys have been conducted by a benthic trawlnet of Dong-baek training ship of Yosu national university during the cruise of 2002-2004. Distribution density showed high value in C5 (north-western area of Jeju Island) with $110.3kg/km^2$ and those of annual mean were about $31-43kg/km^2$. Fishing gears such as nets, pots, octopus jars and etc. were about 42-72% of debris collected in the East China Sea. Composition ratio of rubber, vinyl. metal, plastic, glass, wood, cloth and etc. were within 25% except C5. Rope and drum showed strong fluctuations with 0-30% according to the trawling sites. Some vinyls and nets made in Korea, China and Japan were much collected. It is estimated that fishing gears were discarded to the sea by fishing operation, deliberately or not. An comprehensive program including continuous research, monitoring for marine litters in the Korean sea were necessary.

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Study on the Suitability of Composite Materials for Enhancement of Automotive Fuel Economy (자동차 연비향상을 위한 복합재료 적용 타당성에 관한 연구)

  • Ju, Yeon Jin;Kwon, Young-Chul;Choi, Heung Soap
    • Composites Research
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    • v.32 no.5
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    • pp.284-289
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    • 2019
  • In the present paper, the dynamic force-moment equilibrium equations, driving power and energy equations are analyzed to formulate the equation for fuel economy(km/liter) equivalent to the driving distance (km) divided by the fuel volume (liter) of the vehicle, a selected model of gasoline powered KIA K3 (1.6v). In addition, the effects of the dynamic parameters such as speed of vehicle (V), vehicle total weight(M), rolling resistance ($C_r$) between tires and road surface, inclined angle of road (${\theta}$), as well as the aerodynamic parameters such as drag coefficient ($C_d$) of vehicle, air density(${\rho}$), cross-sectional area (A) of vehicle, wind speed ($V_w$) have been analyzed. And the possibility of alternative materials such as lightweight metal alloys, fiber reinforced plastic composite materials to replace the conventional steel and casting iron materials and to reduce the weight of the vehicle has been investigated by Ashby's material index method. Through studies, the following results were obtained. The most influencing parameters on the fuel economy at high speed zone (100 km/h) were V, the aerodynamic parameters such as $C_d$, A, ${\rho}$, and $C_r$ and M. While at low speed zone (60 km/h), they are, in magnitude order, dynamic parameters such as V, M, $C_r$ and aerodynamic ones such as $C_d$, A, and ${\rho}$, respectively.

Application of Quartz Crystal Microbalance to Understanding the Transport of Microplastics in Soil and Groundwater (토양-지하수내 미세플라스틱 거동 연구를 위한 수정진동자미세저울 기술 소개)

  • Kim, Juhyeok;Myeong, Hyeonah;Son, Sangbo;Kwon, Kideok D.
    • Korean Journal of Mineralogy and Petrology
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    • v.33 no.4
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    • pp.463-475
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    • 2020
  • Presence of microplastics in soil and groundwater has recently been reported and environmental concerns are raised as to the plastic pollution. In the subsurface environment, clay minerals and metal oxide minerals are commonly found as finely dispersed states. Because the minerals have high sorption capacities for diverse pollutants, interactions with mineral surface play an important role in the transport of microplastics in groundwater. Accordingly, environmental mineralogy investigating the interactions between microplastics and mineral surfaces is the essential research area to understand the fate and transport of microplastics in the subsurface environment. The microplastic-mineral surface research requires molecular- to nano-scale analyses to be able to probe the relatively weak interactions between them. The current report introduces a nano-scale analysis tool called quartz crystal microbalance (QCM) that can measure the sorbed/desorbed mass of nanoplastics on mineral surfaces at the level of a few nanograms (~10-9 g). This report briefly reviews the main principles in the QCM measurement and discusses applications of QCM to the environmental mineralogy research.

A Comparative Study on the Object Detection of Deposited Marine Debris (DMD) Using YOLOv5 and YOLOv7 Models (YOLOv5와 YOLOv7 모델을 이용한 해양침적쓰레기 객체탐지 비교평가)

  • Park, Ganghyun;Youn, Youjeong;Kang, Jonggu;Kim, Geunah;Choi, Soyeon;Jang, Seonwoong;Bak, Suho;Gong, Shinwoo;Kwak, Jiwoo;Lee, Yangwon
    • Korean Journal of Remote Sensing
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    • v.38 no.6_2
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    • pp.1643-1652
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    • 2022
  • Deposited Marine Debris(DMD) can negatively affect marine ecosystems, fishery resources, and maritime safety and is mainly detected by sonar sensors, lifting frames, and divers. Considering the limitation of cost and time, recent efforts are being made by integrating underwater images and artificial intelligence (AI). We conducted a comparative study of You Only Look Once Version 5 (YOLOv5) and You Only Look Once Version 7 (YOLOv7) models to detect DMD from underwater images for more accurate and efficient management of DMD. For the detection of the DMD objects such as glass, metal, fish traps, tires, wood, and plastic, the two models showed a performance of over 0.85 in terms of Mean Average Precision (mAP@0.5). A more objective evaluation and an improvement of the models are expected with the construction of an extensive image database.

Effects of Endocrine Disrupting Chemicals on the Nervous System (내분비계 교란물질이 신경계에 미치는 영향)

  • Shin, Hyun Seung;Wi, Jae Ho;Lee, Seung Hyun;Choi, Soo Min;Jung, Eui-Man
    • Journal of Life Science
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    • v.32 no.1
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    • pp.70-77
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    • 2022
  • Endocrine disrupting chemicals (EDCs) have been attracting significant attention in modern society, owing to the increased incidence rate of various diseases along with population growth. EDCs are found in many commercial products, including some plastic bottles and containers, detergents, liners of metal food cans, flame retardants, food, toys, cosmetics, and pesticides. EDCs have a hormonal effect on the human body, which disrupts the endocrine system, notably affecting sexual differentiation and normal reproduction, and can trigger cancer as well. Recently, the association between neurological diseases and EDCs has become a hot topic of research in the field of neuroscience. Considering that EDCs negatively affect not only neuronal proliferation and neurotransmission but also the formation of the neuronal networks, EDCs may induce neurodevelopmental disorders, such as autism spectrum disorders and attention-deficit/hyperactivity disorder as well as neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. In light of these potentially deleterious outcomes, important efforts have been underway to minimize the exposure to EDCs through appropriate regulations and policies around the world, but chemicals that have not yet been associated with endocrine disrupting properties are still in wide use. Therefore, more epidemiological investigations and research are needed to fully understand the effects of EDCs on the nervous system.