• Title/Summary/Keyword: Environmental Charge

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Measurement of Delivery Service Environment for Cold Chain EPS Packaging System of Fresh Food (신선식품 콜드체인 EPS 패키징 시스템의 택배 유통환경 계측)

  • KORAKOT, CHAROENSRI;Kim, SY;Shin, YJ;Jung, HM;Park, JM
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.28 no.1
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    • pp.67-73
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    • 2022
  • The food cold chain refers to a technology and distribution supply chain applied to maintain a constant temperature suitable for the product from production (harvest) to delivery to consumers. In particular, in Korea, the insulation material used in the food cold chain is mostly EPS (Expanded Polystyrene), which is used as a transport container for various food cold chains. However, according to the government's eco-friendly policy, companies charge environmental contributions to the use of EPS, but due to its low price and convenience of handling, it is still used as a container for delivering food. In this study, in order to measure the domestic delivery environment of general refrigerated foods, changes in impact, temperature, and humidity during transport of the EPS packaging system containing foods and ice pack refrigerants were measured. As a result, there were 2?3 sections in which a high impact force of 40 G or more was generated during transport. This can cause damage to the product and EPS container. The difference in temperature and humidity changes by parcel transport routes is more than 30%, so it is necessary to present accurate standards for the domestic cold chain distribution environment. As a result of microbial experiments. the transportation period had a dominant effect on the increase in total viable count and E. coli count.

Development of Defect-Repair Method-Cost Mapping Algorithm of Concrete Bridge Using BMS Data (BMS 데이터를 활용한 콘크리트 교량의 결함-공법-비용 매핑 알고리즘 개발)

  • Lee, Changjun;Park, Wonyoung;Cha, Yongwoon;Jang, Young-Hoon;Park, Taeil
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.2
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    • pp.267-275
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    • 2023
  • As aged infrastructures have been increased, the importance of accurate maintenance costs and proper budget allocation for infrastructure become prominent under limited resources. This study proposed a mapping algorithm between representative defects, repair methods, and the estimated maintenance costs for concrete bridges. In this regard, using BMS (Bridge Management System) data analysis, bridge repair methods were classified and matched with defects according to their locations, types, and sizes. In addition, the maintenance costs were estimated based on the amount of work-load and quantity per unit using CSPR (Cost Standard Production Rate). As a result, the level of accuracy was an average of 85.1 % compared with the actual bill of quantity for Seoul bridge maintenance. The accuracy of maintenance costs is expected to be enhanced by considering the various site conditions such as pier height, extra charge conditions, additional equipment, etc.

Synthesis of Ag-doped black ZnO nano-catalysts for the utilization of visible-light (가시광선 활용을 위한 Ag 도핑 흑색 ZnO 나노 광촉매 합성)

  • Ui-Jun Kim;Hye-Min Kim;Seung-Hyo Lee
    • Journal of the Korean institute of surface engineering
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    • v.56 no.3
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    • pp.208-218
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    • 2023
  • Photocatalysts are advanced materials which accelerate the photoreaction by providing ordinary reactions with other pathways. The catalysts have various advantages, such as low-cost, low operating temperature and pressure, and long-term use. They are applied to environmental and energy field, including the air and water purification, water splitting for hydrogen production, sterilization and self-cleaning surfaces. However, commercial photocatalysts only absorb ultraviolet light between 100 and 400 nm of wavelength which comprises only 5% in sunlight due to the wide band gap. In addition, rapid recombination of electron-hole pairs reduces the photocatalytic performance. Recently, studies on blackening photocatalysts by laser, thermal, and plasma treatments have been conducted to enhance the absorption of visible light and photocatalytic activity. The disordered structures could yield mid-gap states and vacancies could cause charge carrier trapping. Herein, liquid phase plasma (LPP) is adopted to synthesize Ag-doped black ZnO for the utilization of visible-light. The physical and chemical characteristics of the synthesized photocatalysts are analyzed by SEM/EDS, XRD, XPS and the optical properties of them are investigated using UV/Vis DRS and PL analyses. Lastly, the photocatalytic activity was evaluated using methylene blue as a pollutant.

Membrane Containing Biocidal Material for Reduced Biofilm Formation: A Review (미생물막 형성을 막기 위한 살균 물질 함유 막: 총설)

  • Son, Soohyun;Patel, Rajkumar
    • Membrane Journal
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    • v.32 no.1
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    • pp.23-32
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    • 2022
  • Bacteria grow biofilm on various surface such as separation membrane, food packaging film and biomedical device. Growth of biofilm is associated with the formation of a complex structure of exopolysaccharides. Effect of antibacterial effect reduce drastically once the biofilm developed due to the difficulties in mass transport of antimicrobial agent. In order to enhance the antibacterial activity, surface of the membrane is modified, coated or immobilized with functional materials with biocidal properties. One of the idea is to introduce positive charge on the membrane surface by the presence of quaternary ammonium group which might displace divalent metal ion such as magnesium or calcium present in the bacteria cell wall. Efficacy of cell membrane disruption depends on the mobility of the agents available directly on the surface environment. In this review, various biocidal agents like quaternary ammonium group, helamine or zwitter ion containing membrane are discussed.

Damage Analysis of Thin Steel Members with Bolt Connection Using Lamb Wave and PZT Element (Lamb파 전달을 이용한 볼트 연결된 얇은 강판부재의 손상해석)

  • Rhee, Inkyu;Kwak, Hyo-Gyoung;Kim, Jae Hong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.4A
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    • pp.587-596
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    • 2006
  • A half portion of Korean railway bridges depends on the type of steel plate girder bridge. Since these bridges have been built in the early stage of Korean economical boom, numerous maintenance effort suffers from aging and progressive degradation issues at present. In accordance with these efforts, this paper would like to address the detailed analyses of thin steel plates with bolts in order to simulate the connection regions of steel plate girder bridge. The fundamental modal analysis, transient dynamic analysis with 3D piezoelectric element in open circuit loop and signal process with aids of TOF(time of flight) and WC(wavelet coefficient) are extensively discussed.

Optimum Condition of Soil Dispersion for Remediating Heavy Metal-Contaminated Soils using Wet Magnetic Separation (중금속 오염 토양 정화를 위한 습식자력선별법 사용 시 최적 토양분산 조건)

  • Chon, Chul-Min;Park, Jeong-Sik;Park, Sook-Hyun;Kim, Jae-Gon;Nam, In-Hyun
    • Economic and Environmental Geology
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    • v.45 no.2
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    • pp.121-135
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    • 2012
  • Soil dispersion and heavy metal leaching with two heavy metal-contaminated soils were studied to derive the optimal dispersion condition in the course of developing the remedial technology using magnetic separation. The dispersion solutions of pyrophosphate, hexametaphosphate, orthophosphate and sodium dodecylsulfate (SDS) at 1 - 200 mM and the pH of solutions was adjusted to be 9 - 12 with NaOH. The clay content of suspension as an indicator of dispersion rate and the heavy metal concentration of the solution were tested at the different pHs and concentrations of the dispersion solution during the experiment. The dispersion rate increased with increasing the pH and dispersion agent concentration of the solution. The dispersion efficiency of the agents showed as follows: pyrophosphate > hexametaphosphate > SDS > orthophosphate. Arsenic leaching was sharply increased at 50 mM of phosphates and 100 mM of SDS. The adsorption of $OH^-$, phosphates and dodecysulfate on the surface of Fe- and Mn-oxides and soil organic matter and the broken edge of clay mineral might decrease the surface charge and might increase the repulsion force among soil particles. The competition between arsenic and $OH^-$, phosphates and dodecylsulfate for the adsorption site of soil particles might induce the arsenic leaching. The dispersion and heavy metal leaching data indicate that pH 11 and 10 mM pyrophosphate is the optimum dispersion solution for maximizing dispersion and minimizing heavy metal leaching.

A Study on the Health Care Satisfaction and Attitude of Elementary School Students - by the presence or absence of nurse teacher - (초등학생의 보건관리 만족도와 태도에 관한 연구 - 양호교사 유무를 중심으로 -)

  • Park, Dong-Kwon;Park, Young-Soo
    • The Journal of Korean Society for School & Community Health Education
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    • v.1 no.2
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    • pp.49-71
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    • 2000
  • The purpose of this study was to serve as a basis for school health care of better quality, by making a comparative analysis of the health care satisfaction and attitude of elementary school students in consideration of their general characteristics and the presence or absence of nurse teacher. The subjects in this study were 919 selected six graders in 16 elementary schools in the city of Tongduchun, Koyang and Euijungbu, Yangju-kun and Yeunchun-kun. A survey was conducted with questionnaire designed for measurement of health care satisfaction and attitude. As a result of analyzing the data collected from June 1 through 15, 2000, the conclusions were as follows. 1) As for the general characteristics of the students investigated, the subjects included 513 boys(55.8%) and 406 girls(44.2%). The schools where 390(42.4%) students attended were located in municipal area, and the schools where 529(57.6%) students attended were located in kun area. 608(66.2%) students had a nurse teacher at their schools, while 311(33.8%) students had no nurse teacher. 498(54.2%) had an experience to use the health room this year, but 421(45.8%) had no such an experience. Their mean school life satisfaction was scored $3.42{\pm}.71$, above the average. And their health condition was rated $3.81{\pm}.87$, which implied they tended to be in good health. 2) The mean satisfaction at the health room operation was scored $3.33{\pm}.71$, above the medium level. What they were most satisfied with($4.02{\pm}1.08$) was, among the health room facilities, that there were beds. But they expressed the least satisfaction($2.83{\pm}1.17$) at the location of health room. The presence or absence of nurse teacher made a significant difference to their satisfactionat health room operation, because the students in schools with nurse teacher showed greater satisfaction($3.42{\pm}.72$) than the others in schools with no nurse teacher did($3.15{\pm}.66$). 3) Concerning their attitude to use the health room in case of disease or accident occurrence, a lot of students in schools with a nurse teacher, who had ever suffered from indigestion, headache or traumatic injury, used the health room. In schools with no nurse teacher, there was a tendency to talk to their class teachers(p<.001). The recognition of the necessity for health counseling was generally on a medium level. The counselor whom they wanted to discuss health problem with was family or friend in the largest cases. Few students discussed with class teachers in case there was a nurse teacher in school. Instead, some of them discussed with friend, family or nurse teacher, and there was a significant difference between them(p<.001). 4) The mean satisfaction at health, sanitation and environmental management was rated $3.20{\pm}.90$, above the average. The classroom lighting gave them the best satisfaction with $3.67{\pm}1.07$, but the satisfaction at toilet cleanness and disinfection was not good with $2.83{\pm}1.19$. By the presence or absence of nurse teacher, those who had a nurse teacher expressed better satisfaction at water supply facilities including hot water than the others who had no nurse teacher did(p<.001). But no significant difference was observed in the other items. 5) The health education satisfaction was rated $3.19{\pm}.99$, which was on a medium level. By item, the mean satisfaction level was $3.36{\pm}1.19$ at nurse teacher's explanation about treatment, $3.13{\pm}1.15$ at the frequency of health education, and $3.08{\pm}1.16$ at the explanation on the cause of disease. By the presence or absence of nurse teacher, the students with nurse teacher showed significantly better satisfaction at every factor0(p<.001). 6) Regarding health education attitude, their recognition of the need for school health education was scored $3.89{\pm}.96$. Those who had a nurse teacher felt it more necessary($3.96{\pm}.92$), yet the others who had no nurse teacher felt its necessity a little less($3.74{\pm}1.01$). The most preferred thing for them to learn in health education was first aid, followed by sex education, obesity prevention, safety accident prevention in school and outdoors, smoking-related health, good use of leisure time, and environmental pollution cause in the order named. According to the presence or absence of nurse teacher, there was a significant difference in sex education(p<.01), but no significant disparities were found in the other factors. The most preferred person who would offer health education was a lecturer from the outside(45.8%) and nurse teacher(45.4%). Their preference for class teacher as a person in charge of health education was just 8.8%. But the presence or absence of nurse teacher didn't produce any differences to their preference for a person in charge of health education.

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Changes of Mineralogical Characteristics of Precipitates in Acid Mine Drainage of the Dalsung Mine and Related Changes of Trace Elements (달성광산 산성광산배수 침전물의 시간에 따른 광물상 특성 변화 및 이에 따른 미량원소의 거동 변화)

  • Yoon, Young Jin;Kim, Yeongkyoo;Lee, Seong-joo
    • Economic and Environmental Geology
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    • v.55 no.5
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    • pp.531-540
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    • 2022
  • Various iron minerals that precipitate in acid mine drainage have a great influence on the concentration change and mobility of trace elements in the drainage during phase transition to other minerals as well as the precipitation process. This study investigated the change of mineral properties and the behaviors of trace elements influenced by pH and time for the precipitates collected from the acid mine drainage treatment system of the Dalsung mine, where schwertmannite is mainly precipitated. However, the main mineral precipitated in the drainage was goethite, suggesting schwetmannite has already undergone a phase transition to goethite to some extent, and it was observed that at higher pH, the peak width at half maximum of XRD peak was narrower. This can be interpreted as the transformation of small amount of amorphous schwetmannite to goethite or an increase in the crystallinity of goethite, and it showed that the higher the pH, the greater this change was. The concentration of Fe was also greatly affected by the pH values, and as the pH increased, the concentration of Fe in the drainage decreased. With increasing time, the Fe concentration increased and then decreased, which can be interpreted to indicate the dissolution of schwertmannite and precipitation of goethite. This mineral change probably resulted in the rapid increase of the concentration of S at initial stage, but its concentration was stabilized later. The concentration of S is also related to the stability of schwetmannite, showing a high concentration at a low pH at which schwertmannite is stable and a low concentration at a high pH at which goethite is stable. The trace elements present as cations in the drainage also showed a close relationship with the pH, generally the lower the pH, the higher the concentration, due to the solubility changes by the pH, and the precipitation and the changes in mineral surface charge at high pH. On the other hand, in the case of As, existing as an anion, although it showed a high concentration at low pH, its concentration increased with time at all pH values, which is probably related to the concentration of Fe which can be coprecipitated in the drainage, and the increase of As concentration with time is also considered to be related to the decrease in schwertmannite rather than the mineral surface charge.

Mesoporous Carbon Electrodes for Capacitive Deionization (축전식 탈염 공정을 위한 메조포러스 탄소 전극)

  • Lee, Dong-Ju;Park, Jin-Soo
    • Journal of the Korean Electrochemical Society
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    • v.17 no.1
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    • pp.57-64
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    • 2014
  • Carbon electrodes for capacitive deionization were fabricated through mixing two different carbon powders (activated carbon powder, carbon black) with different particle sizes to investigate physical or electrochemical properties and finally desalination performances of the electrodes with various compositions of two carbon powders in weight and were compared with the electrode consisting of activated carbon. As a result, the electrode structure became more packed as increasing the amount of carbon black and resulted in 10% increase in mesopore fraction. The specific capacitance obtained from cyclic voltammograms of various electrodes showed that the electrode containing carbon black only had 107.4 F/g, while the specific capacitance of the electrode having more amount of carbon black increased and was higher than the one having no carbon black. The results of desalination runs in a capacitive deionization cell exhibited that the electrode having the highest amount of carbon black (1 wt%) in this study had the highest desalting efficiency, and no significant pH variation was observed during the runs. It was analyzed using accumulated charge that the fraction of non-Faraday current increased as the amount of carbon black increased in the electrodes. It can be concluded that the addition of carbon black changed the electrode structure resulting in an increase in the fraction of mesopore and finally enhanced the desalting efficiency by decreasing Faraday current.

Comparison of Survey Methods and Results for Natural Environment in Baekdudaegan Mountain System (백두대간 자연 환경 조사 비교 및 개선 방안 고찰)

  • Shin, Moon-hyun;Kim, Jung-hwan;Kwon, Jino;Lim, Joo-hoon;Choi, Hyung Tae;Park, Chanwoo
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.19 no.2
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    • pp.1-18
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    • 2016
  • Baekdudaegan Mountain System (BDMS) is a unique and traditional concept in Korea that puts importance on the connectivity of energy when Korean people recognize their mountain system. Two main national organizations that are in charge of managing natural environment in Korea, Korea Forest Service (KFS) and Ministry of Environment (MoE), have been independently investigating the natural resources in protected areas of BDMS. Each organization released its first survey report for the whole protected areas in 2011. In order to provide better understanding of BDMS's natural environment, the results contained in the first reports of KFS and MoE were compared. It was found that KFS contains a wider variety of survey items, though many of the items are overlapped between the reports of KFS and MoE. It was noticeable that the survey results of KFS and MoE were not always matched even for the same or similar items in the identical target areas. The main causes of the different survey results are suggested to be the differences of the details of the survey conditions between KFS and MoE, such as the season of the surveys and the subjectivity of surveyors, and the type of literatures included in the indoor survey. As a result, it is difficult to directly compare the survey results of KFS and MoE, which leads to low usability of the data and low efficiency of the survey processes. Therefore, it is strongly recommended that the sections and methodologies of survey should be clearly set with consideration for the research purposes. The survey data and geographical information should be digitalized and opened to the public for better accessibility to BDMS information. Also, the survey reports should include English summary, thereby the results can be utilized globally for scientific, cultural and political purposes, such as designation of a heritage site.