• Title/Summary/Keyword: Recovery Classification

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Current Research Trends for Treatment of Microplastics (미세플라스틱 처리를 위한 연구동향)

  • Kim, Seong-Min;Baek, Sang-Ho;Han, Yosep;Davaadorj, Tsogchuluun;Go, Byung-Hun;Jeon, Ho-Seok
    • Resources Recycling
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    • v.29 no.5
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    • pp.15-27
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    • 2020
  • Microplastics are recognized as critical and serious environmental problem in worldwide. Plastics are inexpensive, lightweight, excellent in processability, and various in material-specific properties. Along industrial development, the production and disposal amount of plastics are also rapidly increasing. In particular, abundant plastic wastes are eventually disposed into marine environment with harmful impacts on the ecosystem. Therefore, lots of relevant studies were recently progressed in various fields. However, many studies are being just conducted due to its difficulty in applying a general treatment method for those small particle sizes and their various characteristics. In the meantime, lots of researches are being conducted on applying methods using physical properties such as specific gravity, magnetic, and electrostatic separation, which are beneficiation processes of minerals. However, since it is still in the laboratory stage, the development of larger scale separation technology for efficient treatment is urgent.

A Study on Radio Wave Management Regulations in the United States to Improve the Domestic Radio Wave Management System (국내 전파관리 제도 개선을 위한 미국의 전파관리규제에 대한 연구)

  • Yoon, Chan-Ho;Seok, Gyeong-Hyu
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.3
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    • pp.379-388
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    • 2020
  • The contents and scope of this study are to analyze the problems of the current radio service and radio station classification system, and to investigate the radio wave management cases in the United States to provide a reasonable and efficient radio wave management method. The results of this study can be used as basic data when revising the legal system regarding radio wave enforcement regulations, radio service and radio station classification standards. It is expected that in the future, a detailed commentary on the definition and classification system of new radio / radio stations will be prepared to increase policy compliance in practice, while contributing to enhancing the consistency and efficiency of radio station licensing and inspection.

Detection of Wildfire-Damaged Areas Using Kompsat-3 Image: A Case of the 2019 Unbong Mountain Fire in Busan, South Korea

  • Lee, Soo-Jin;Lee, Yang-Won
    • Korean Journal of Remote Sensing
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    • v.36 no.1
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    • pp.29-39
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    • 2020
  • Forest fire is a critical disaster that causes massive destruction of forest ecosystem and economic loss. Hence, accurate estimation of the burned area is important for evaluation of the degree of damage and for preparing baseline data for recovery. Since most of the area size damaged by wildfires in Korea is less than 1 ha, it is necessary to use satellite or drone images with a resolution of less than 10m for detecting the damage area. This paper aims to detect wildfire-damaged area from a Kompsat-3 image using the indices such as NDVI (normalized difference vegetation index) and FBI (fire burn index) and to examine the classification characteristics according to the methods such as Otsu thresholding and ISODATA(iterative self-organizing data analysis technique). To mitigate the salt-and-pepper phenomenon of the pixel-based classification, a gaussian filter was applied to the images of NDVI and FBI. Otsu thresholding and ISODATA could distinguish the burned forest from normal forest appropriately, and the salt-and-pepper phenomenon at the boundaries of burned forest was reduced by the gaussian filter. The result from ISODATA with gaussian filter using NDVI was closest to the official record of damage area (56.9 ha) published by the Korea Forest Service. Unlike Otsu thresholding for binary classification,since the ISODATA categorizes the images into multiple classes such as(1)severely burned area, (2) moderately burned area, (3) mixture of burned and unburned areas, and (4) unburned area, the characteristics of the boundaries consisting of burned and normal forests can be better expressed. It is expected that our approach can be utilized for the high-resolution images obtained from other satellites and drones.

Analysis of Crushing/Classification Process for Recovery of Black Mass from Li-ion Battery and Mathematical Modeling of Mixed Materials (폐배터리 블랙 매스(black mass) 회수를 위한 파쇄/분급 공정 분석 및 2종 혼합물의 수학적 분쇄 모델링)

  • Kwanho Kim;Hoon Lee
    • Resources Recycling
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    • v.31 no.6
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    • pp.81-91
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    • 2022
  • The use of lithium-ion batteries increases significantly with the rapid spread of electronic devices and electric vehicle and thereby an increase in the amount of waste batteries is expected in the near future. Therefore, studies are continuously being conducted to recover various resources of cathode active material (Ni, Co, Mn, Li) from waste battery. In order to recover the cathode active material, black mass is generally recovered from waste battery. The general process of recovering black mass is a waste battery collection - discharge - dismantling - crushing - classification process. This study focus on the crushing/classification process among the processes. Specifically, the particle size distribution of various samples at each crushing/classification step were evaluated, and the particle shape of each particle fraction was analyzed with a microscope and SEM (Scanning Electron Microscopy)-EDS(Energy Dispersive Spectrometer). As a result, among the black mass particle, fine particle less than 74 ㎛ was the mixture of cathode and anode active material which are properly liberated from the current metals. However, coarse particle larger than 100 ㎛ was present in a form in which the current metal and active material were combined. In addition, this study developed a PBM(Population Balance Model) system that can simulate two-species mixture sample with two different crushing properties. Using developed model, the breakage parameters of two species was derived and predictive performance of breakage distribution was verified.

LAN-Based Protective Relaying for Interconnect Protection of Dispersed Generators (LAN을 이용한 분산전원 연계 계통의 보호)

  • Jyung, Tae-Young;Baek, Young-Sik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.3
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    • pp.491-497
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    • 2007
  • As dispersed generators was driven in condition interconnecting with utility, it could cause a variety of new effects to the original distribution system that was running as considered only the one-way power flow. Therefore, the protection devices that is builted in distribution system should be designed to be able to operate with disposing of not only a fault of the generator, but also utility condition. Especially, the fault of the feeder interconnected with Dispersed Generator can cause the islanding phenomenon of open DG(Dispersed Generators). This phenomenon has many problems such as a machinery damage, electricity qualify degradation and a difficulty of the system recovery. In the fault therefore, we must separate Dispersed Generator from the system quickly. In this paper, for the fault classification of the interconnected DG and the outside feeder we judge the fault of the interconnected DG and the outside feeder in HMI through data provided by IED(Intelligent Electronic Device) on the network and decide whether it operates or not by sending the result to each relay.

A study on the possibility of reconfigurations of architectural cultural assets spatial Information by BIM -The case of spatial configurations of Sungnyemun recovery process- (BIM기반 건축문화재 공간정보 구성방식의 보완 가능성 -숭례문 복구공정 3차원 정보구축 사례를 중심으로-)

  • Choi, Hyun-Sang
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.294-295
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    • 2014
  • Recently, it is becoming necessary for architectural heritage to make spatial information structure by using BIM(Building Information Modeling). However, current BIM system can not be used because its information classification and structure is not suitable for architectural heritage. This is a basic study which focuses on upgrading spatial information structure of BIM so that it would be possible to use BIM in management of preservation of architectural heritage, too. This study analyzes Sungnyemun case and its spatial information structure.

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Recovery of abrasives from electrical industry sludge

  • Cho Sung-Baek;Kim Sang-Bae;Cho Keon-Joon
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.637-641
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    • 2003
  • Abrasive powders were recovered from electrical industry sludge by simple physical separation for their recycling. The raw electrical industry sludge was filter pressed, dried, dispersed and then classified by air classifier at various conditions. The three kinds of particles with different particle size distribution were classified by controlling rotor speed and air volumes of the classifier. The recovered abrasive powders, which are classified at 5,000,9000 and 13,000 rpm of rotor speed, are almost same properties to raw pumice, garnet and rouge powders, respectively. The results of particle size analysis, X-ray diffraction and SEM observation show that the recovered powders can be reused as an abrasive powders.

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Comparative Study of Design Methods for Manufacturing of Steel Structure (철구조물의 설계방법에 대한 비교 연구)

  • Kim, Dong-Kwon;Choi, Jae-Seung;Hwang, Suk-Hwan
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.357-362
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    • 2000
  • Allowable stress design(ASD) method has been widely used to design steel structures such as boiler and heat recovery steam generator(HRSG) of power plant. However, many researchers are recently intrested in road and resistance factor design(LRFD) method which may take the place of ASD. In this work, the weight calculation of steel structure was compared when ASD and LRFD were applied respectively. For the calculation of weight of steel structure, computer program was developed and applied to obtain beam weight. Using this program and GTSTRUDL, structural design program, weight of steel structure is calculated. As a result of weight calculation, maximum 5.4% of weight reduction is achieved among examples of this study by applying LRFD comparing with the result of ASD, and those results quite dependent on the applied load and member classification.

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Simultaneous Determination of (-)-Menthone and (-)-Menthol in Menthae Herba by Gas Chromatography and Principal Component Analysis

  • Kim, Jung-Hoon;Seo, Chang-Seob;Shin, Hyeun-Kyoo
    • Natural Product Sciences
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    • v.16 no.3
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    • pp.180-184
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    • 2010
  • The simple and accurate method was established for the simultaneous determination of (-)-menthone and (-)-menthol in Menthae herba obtained from Korea and China. A quantitative analysis was performed with a gas chromatography-flame ionization detector and reference compounds were separated on a capillary HP-Innowax column (30 m $\times$ 0.23 mm, 0.50 ${\mu}m$, Agilent, MA, USA). The correlation coefficients of the compounds showed good linearity ($r^2$ > 0.9997) over the linear range. The precision, repeatability and stability showed less than 1.7% of relative standard deviation (RSD) values for two compounds. Recovery rates were within the range of 95.72 - 103.76%. The method was applied successfully to analyze 15 samples of Menthae herba and achieved sufficient and specific separation of reference compounds. The principal component analysis (PCA) exhibited the classification of 15 samples according to their locations of origin.

Development of a Technology Cost Model for Advanced Manufacturing Systems (첨단생산시스템을 위한 기술원가모델의 개발)

  • Park, Ju-Chull
    • IE interfaces
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    • v.8 no.1
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    • pp.31-43
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    • 1995
  • This study is intended to develop a technology cost model (TCM) which treats technology costs appropriately under present advanced manufacturing technology environment. TCM is composed of two elements : cost classification system and cost allocation model. It is proposed to include technology-related department expenses as well as technology investment in the categories of technology costs. For the cost allocation, technology activities are divided into four homogeneous groups. Costs are accumulated into one of the four cost pools and allocated to the cost object using the pool's unique allocation base. It is also proposed to use the capital recovery costs including interest expense rather than the depreciation costs for an invested capital. A case study is performed to verify the applicability of the developed model.

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