Rare earth elements, which are important components of motors, are in high demand and thus constantly get more expensive. This tendency is driven by the growth of the electric vehicle market, as well as environmental issues associated with rare-earth metal manufacturing. TC 298 of the ISO manages standardization in the areas of rare-earth recycling, measurement, and sustainability. Korea, a resource-poor country, is working on international standardization projects that focus on recycling and encouraging the domestic adoption of international standards. ITU-T has previously issued recommendations regarding the recycling of rare-earth metals from e-waste. ISO TC 298 expands on the previous recommendations and standards for promoting the recycling industry. Recycling-related rare earth standards and drafts covered by ISO TC 298, as well as Korea’s strategies, are reviewed and discussed in this article.

The purpose of this study was to assess consumption and satisfaction with fresh-cut produce in Korean adults. In this study, an online survey November 9~13, 2020 was conducted with 982 Korean adults age 19~64 (490 males and 492 females) with experience in purchasing fresh-cut produce in the past year. Among all respondents, the percentage with experience in buying ‘washed or peeled vegetables’ was the highest (71.18%), followed by those in buying ‘packaged salads/sprouts/ssam vegetables’ (64.15%), ‘pre-cut fruits/fruit cups’ (59.98%), ‘pre-cut or minced vegetables’ (56.01%), and ‘washed or peeled fruits’ (53.67%), respectively. Among the types of fresh-cut produce, ‘packaged salads/sprouts/ssam vegetables’ showed the highest satisfaction score at 3.73 pts, and the overall satisfaction score of fresh-cut produce consumption was also 3.73 pts. Compared to male respondents, female respondents showed a significantly higher percentage of respondents that purchased ‘packaged salads/sprouts/ssam vegetables’ (p=0.0409), significantly higher satisfaction scores (p=0.0124), and a higher percentage of respondents considering ‘freshness’ important when purchasing (p<0.0001). Additionally, the group with high household income comprised a significantly higher ratio of respondents considering ‘eco-friendly or organic status’ important. The study results may facilitate identify areas for improvement of fresh-cut produce in the future.

본 연구는 2020년 5월부터 10월까지 4대강 사업의 하나로 준공된 8개의 낙동강 보 구간에 서식하는 저서성 대형무척 추동물의 생물다양성 변화와 군집분석을 수행하였으며, 2010년부터 2020년까지 약 10년간의 저서성 대형무척추동물 주요 분류군에 대한 변화상을 분석하였다. 조사결과 저서성 대형무척추동물은 총 3문 5강 18목 52과 83속 97종 128.1개 체/m2가 출현하였으며, 오염지표생물인 깔따구류(Chironomidae sp.)와 실지렁이류(Tubificidae spp.)가 전체적으로 우점하였다. 군집분석결과 우점도지수는 평균 0.62±0.20이고 다양도지수는 1.87±0.63로 낙동강 보 상류에서 가장 안정적으로 분석되었다. 낙동강 보 중앙부에서는 실지렁이가 우점하였으며, 칠곡보와 강정고령보에서 가장 불안한 군집구조가 나타났다. 군집안정성 분석결과 상대적 회복력과 저항력이 높은 특성군I이 높게 나타났으며, 저항력과 회복력이 낮은 특성군III이 소수 분포하는 것으로 나타나 현재 낙동강 보 구간의 군집은 매우 불안한 상태로 분석되었다. 섭식기능군에서는 잡아먹는무리가 비교적 높게 출현하였고, 썰어먹는무리, 모아먹는무리, 걸러먹는무리는 낮게 나타났 다. 서식기능군에서는 굴파는무리와 기어오르는무리가 우세하게 출현하여 대부분 용존산소가 낮은 정수생태계에서 출현하는 기능군들이 많이 분포하고 있는 것으로 나타났다. 주요 법적보호종으로는 상주보와 낙단보에서 멸종위기야생 생물 II급인 노란잔산잠자리(Macromia daimoji)가 분포하고 있는 것으로 확인되었다. 과거부터 10년간의 분석결과 종수와 개체수는 댐 공사 직후에는 증가하였지만, 2016년 이후부터 급감하면서 다시 안정화되고 있는 것으로 나타났다. 우점종으로는 깔따구류가 모든 지점에서 우점하는 것으로 나타났으며, 현재 약 50% 수준의 비율로 유지되고 있는 것으로 나타났다. EPT 그룹은 2011년을 기점으로 대폭 감소하였으며, 이중 강도래목과 날도래목은 회복하지 못하는 것으로 분석되었다. 오염지표생물인 실지렁이류는 2012년 공사 완료 후 증가 추세를 보였으며, 2015년과 2020년에 개체수가 폭발적으로 증가하였다. 멸종위기야생생물 I급으로 지정된 귀이빨대칭이(Cristaria plicata)는 2011년 합천창 녕보에서 출현 후 관찰되지 않았으며, 멸종위기야생생물 II급인 노란잔산잠자리는 2015년까지 7개의 구간에서 드물게 확인되었으나 현재 분포 서식처가 급격히 줄어든 것으로 확인되었다.

정수기는 일반적인 산업용 막여과 수처리 공정과 다르게 운전과 휴지를 반복하는 특성이 있다. 이러한 특징 때문 에 역삼투막을 사용하는 정수기의 경우, 재정수시에 정수수의 농도가 정상적인 값보다 높게 나오는 현상(제거율이 정상값보 다 낮게 나오는 현상)이 있는데, 이를 “TDS creep”이라고 한다. 본 연구에서는 휴지시간과 농도에 따른 TDS creep 정도를 관 찰하였다. 또한, TDS creep 현상을 저감하기 위해 원수 세척, 정수부의 부피 증가 및 정수 세척 방법 등을 시험하였고 이에 대한 실질적인 효과를 관찰하였다. 이러한 방법들 중에 정수수의 세척과 같이 역삼투막의 feed side와 permeate side의 농도차 를 최소화하는 것이 TDS creep 현상을 해소하는 궁극적인 해결책임을 확인하였다.

This study aimed to examine cucumber (Cucumis sativus) varieties adaptive to the desert climate by comparing and analyzing the growth, yield, and water consumption. Two long-sized cucumber varieties, ‘Gulfstream’ and ‘Imea’ and two medium-sized cucumbers, ‘Nagene’ and ‘Sausan’ were cultivated in coir substrate hydroponics under hot and humid greenhouse conditions from March 2 to June 20, 2020. On the 113 DAT, ‘Nagene’ had the longest plant height and the highest internode number. The marketable fruit number per plant was higher in the medium-sized varieties, which had more internode number. The marketable fruit number was 31.3 for ‘Gulfstream’, 30.7 for ‘Imea’, 57.8 for ‘Nagene’, or 56.0 for ‘Sausan’ with no significant difference in total fruit weights per plant. The water consumption required to produce 200 g of fruit was lower in the ‘Nagene’ (2.39 L) with the highest water use efficiency (WUE). Therefore, ‘Nagene’ variety may have higher adaptability to desert high temperature compared to the long-sized varieties, and it is going to be necessary to verify more medium-sized cucumber varieties.

In this study, the removal efficiency of PFCs(perfluorinated compounds) in the GAC(granule activated carbon) process based on the superheated steam automatic regeneration system was investigated in laboratory scale and pilot-scale reactor. Among PFCs, PFHxS(perfluorohexyl sulfonate) was most effectively removed. The removal efficiency of PFCs was found to be closely related to the EBCT, and the removal efficiencies of PFOA(perfluorooctanoic acid), PFOS(perfluorooctyl sulfonate), and PFHxS were 43.7, 75, and 100%, respectively, under the condition of EBCT of 6 min. Afterward, PFOA, PFOS, and PFHxS exhibited the earlier breakthrough time in the order. After that, GAC was regenerated, and the removal efficiency of the PFCs before and after regeneration was compared. As a result, it was shown that the PFCs removal efficiency in the regenerated GAC process were higher, and that of PFOA was improved to 75%. The findings of this study indicate the feasibility of the superheated steam automatic regeneration system for the stable removal of the PFCs, and it was verified that this technology can be applied stably enough even in field conditions.

본 연구는 설악산국립공원 아고산대에서 출현하는 주요 식생의 지역별, 해발고별 식생구조를 파악하고, 식물상 목록을 작성하고자 수행되었다. 기존 아고산대 연구결과를 고찰하고, 사전조사를 통해 아고산대 식생이 처음 출현하는 지점을 남측을 기준으로 800m로 결정하고 그곳에서부터 해발고도 50m 간격으로 북측 백담사~마등령 탐방로(BD) 12개소, 서측 한계령~끝청 탐방로(HG) 13개소, 동측 신흥사~소청봉 탐방로(SA) 13개소, 남측 오색~끝청, 오색~대청봉 탐방로(OS) 39개소에 각각 조사구를 설치하여 총 77개소에서 현장조사를 수행하였다. 분석결과, 아고산대 주요 식물인 신갈나무, 사스래나무, 분비나무 등의 출현 여부에 따른 종조성과 지역 및 해발고도에 의해 신갈나무-전나무-당단풍나 무군락, 신갈나무-피나무군락, 신갈나무-잣나무군락, 신갈나무-당단풍나무군락, 사스래나무-분비나무군락, 잣나무-분 비나무군락, 낙엽활엽혼효군락의 총 7개 군락으로 분류되었다. 조사구(100㎡)당 10.68±2.98종이 출현하였고, 110.87± 63.89개체가 확인되었다. 종다양성지수 분석결과, 설악산국립공원 아고산대 식생군락은 다양한 수종이 중요종으로 출현하는 혼효림으로 판단되었다. 지역별로 아고산대 주요 식물이 출현하는 최초 해발고도는 차이가 있었지만, 1,100~ 1,300m 구간에서 집중적으로 분포하고 있었다. 관속식물은 총 83과 193속 289종 4아종 28변종 1품종 322분류군으로 파악되었다. 법정보호종은 기생꽃 1분류군이 확인되었다. 한반도 고유종은 19종이 확인되었으며, 아고산식물은 58분류 군이 확인되었다.

The frequent detection and occurrence of micropollutants (MPs) in aquatic ecosystems has raised public health concerns worldwide. In this study, the behavior of 50 MPs was investigated in three different domestic wastewater treatment plants (WWTPs). Furthermore, the Kruskal-Wallis test was used to assess the geographical and seasonal variation of MPs in the WWTPs. The results showed that the concentrations of 43 MPs ranged from less than 0.1 to 237.6 μg L-1, while other seven MPs including 17-ethynylestradiol, 17-estradiol, sulfathiazole, sulfamethazine, clofibric acid, simvastatin, and lovastatin were not detected in all WWTPs. Among the detected MPs, the pharmaceuticals such as metformin, acetaminophen, naproxen, and caffeine were prominent with maximum concentrations of 133.4, 237.6, 71.5, and 107.7 μg L-1, respectively. Most perfluorinated compounds and nitrosamines were found at trace levels of 1.2 to 55.3 ng L-1, while the concentration of corrosion inhibitors, preservatives (parabens), and endocrine disruptors ranged from less than 0.1 to 4310.8 ng L-1. Regardless of the type of biological treatment process such as MLE, A2O, and MBR, the majority of pharmaceuticals (except lincomycin, diclofenac, iopromide, and carbamazepine), parabens (except Methyl paraben), and endocrine disruptors were removed by more than 80%. However, the removal efficiencies of certain MPs such as atrazine, DEET, perfluorinated compounds (except PFHxA), nitrosamines, and corrosion inhibitors were relatively low or their concentration even increased after treatment. The results of statistical analysis reveal that there is no significant geographical difference in the removal efficacy of MPs, but there are temporal seasonal variations in all WWTPs.

A number of studies have been conducted to confirm the preventive effect of xylitol on dental caries as a whole or partial alternative to dietary sugars. This study reviewed the oral health effects of xylitol on the prevention mechanism of dental caries, the prevention of dental caries, the inhibition of mother-to-child transmission, and the oral health effects in the elderly based on existing studies on the oral health of xylitol. Carbohydrates and dietary sugars in food are fermented by acid-producing microorganisms in the mouth and produce dental plaque and acid, which cause dental caries. However, most dental decay-causing bacteria cannot produce acids by metabolizing xylitol. Xylitol, stored in cells as a non-metabolizable metabolite by Streptococcus mutans (S. mutans), affects bacterial glucose metabolism and inhibits bacterial growth. Xylitol consumption also reduces the amount of plaque and the population of S. mutans in both plaque and saliva. In addition, xylitol acts in the remineralization process. Xylitol has been confirmed to effectively prevent dental caries, inhibit mother-to-child transmission of MS, prevent dental caries, and increase salivary flow in the elderly. In conclusion, xylitol is an adequate sugar substitute for dental health, from infants to the elderly. For future studies, the researchers recommend reviewing the effects of xylitol on the oral and intestinal microbial environment and the side effects of excessive intake.

Powder flowability is critical in additive manufacturing processes, especially for laser powder bed fusion. Many powder features, such as powder size distribution, particle shape, surface roughness, and chemical composition, simultaneously affect the flow properties of a powder; however, the individual effect of each factor on powder flowability has not been comprehensively evaluated. In this study, the impact of particle shape (sphericity) on the rheological properties of Ti-6Al-4V powder is quantified using an FT4 powder rheometer. Dynamic image analysis is conducted on plasma-atomized (PA) and gas-atomized (GA) powders to evaluate their particle sphericity. PA and GA powders exhibit negligible differences in compressibility and permeability tests, but GA powder shows more cohesive behavior, especially in a dynamic state, because lower particle sphericity facilitates interaction between particles during the powder flow. These results provide guidelines for the manufacturing of advanced metal powders with excellent powder flowability for laser powder bed fusion.

Recently, the purchase of fresh-cut produce and meal kits has increased. Ready-to-eat (RTE) fresh-cut products have potentially hazard of cross-contamination of various microorganisms in the processes of peeling, slicing, dicing, and shredding. There are frequent cases of protozoa food poisoning, such as Cyclospora and Cryptosporidium, caused by fresh-cut products. The objective of the study is to investigate the microbiological qualities of various types of RTE fresh-cut products in the domestic on/offline markets. RTE fresh-cut fruits cup (n=100), fresh-cut vegetables (n=50), and vegetables in meal kits (Vietnamese spring rolls and white radish rolls kits, n=50) were seasonally analyzed. The contamination levels of hygienic indicator organisms, yeast and mold (YM), and foodborne pathogens (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Salmonella spp., and Escherichia coli O157:H7) were monitored. Overall, the lowest microbiological qualities of meal kits vegetables were observed, followed by RTE fresh-cut fruits cup and fresh-cut vegetables. Contamination levels of total aerobic bacteria, coliforms, and YM in meal kits vegetables were 5.91, 3.90, and 4.71 logs CFU/g, respectively. From the qualitative analysis, 6 out of 200 RTE fresh-cut products (3%) returned positive result for S. aureus. From the quantitative analysis, the contamination levels of S. aureus in purple cabbage from a meal-kit and fresh-cut pineapple were below the acceptable limit (100 CFU/g). Staphylococcus enterotoxin seg and sei genes were detected in RTE fresh-cut celery and red cabbage from meal-kits, respectively. S. aureus contamination must be carefully controlled during the manufacturing processes of RTE fresh-cut products. Neither Cyclospora cayetanensis nor Cryptosporidium parvum was detected in the samples of RTE fresh-cut products and vegetables from meal-kits from the Korean retail markets.

Acute cholangitis is a clinical syndrome characterized by fever, jaundice, and abdominal pain that develops as a result of stasis and infection in the biliary tract. It can be a life-threatening condition if it is not recognized early. Patients with severe cholangitis may present with hypotension, and mental status changes. The most frequent causes of acute cholangitis are biliary calculi, benign biliary stricture, and malignancy. The most common pathogens isolated are gram-negative bacteria (Escherichia coli , followed by Klebsiella species and Enterobacter species). A diagnosis of acute cholangitis requires evidence of systemic inflammation, cholestasis, and imaging with biliary obstruction. Imaging studies may consist of ultrasound, computed tomography, magnetic resonance cholangiopancreatography, and/or endoscopic ultrasound. The mainstay of treatment consists of fluid resuscitation, antibiotics, and biliary drainage. Penicillin/β-lactamase, third-generation cephalosporin, or carbapenem are all acceptable choices for first-line treatment. In patients with severe cholangitis, biliary drainage should be performed within 24 hours. Patients with severe acute cholangitis require urgent (within 24 hours) biliary decompression. Endoscopic retrograde cholangiopancreatography remains the preferred modality for biliary drainage. In conclusion, acute cholangitis is mostly treatable when recognized and treated early. Recognizing and initiating early treatment leads to markedly decreased patient morbidity and mortality.

본 연구는 에니어그램 배형의 중소기업 경영자가 인식하는 리더십 유형과 특 성을 파악하기 위해 과학적으로 주관적인 의미를 측정할 수 있는 Q 방법론을 활용하여 분석하였다. 인터뷰와 선행연구를 통하여 200개의 Q모집단을 구성한 다음 40개의 진술문으로 Q 표본으로 선정하였다. 연구에 사용된 P샘플은 중소 기업 경영자 중 에니어그램 배형 23명을 선정하여 Q분류 과정을 통해 나온 자 료를 QUANL 프로그램을 사용하여 주성분 요인 분석을 실시하였다. 연구결과 유형 1은 ‘팔로워의 성장을 돕는 비전제시형’ 유형 2는 ‘팔로워에 대한 책임감이 강한 외강내유형’ , 유형 3은 ‘일보다 사람이 우선인 팔로워중심형’, 유형 4는 ‘팔 로워에게 모범이 되는 자기관리형’으로 나타났다. 이상의 연구 결과를 통하여 에니어그램 배형의 중소기업 경영자가 인식하는 리더십을 유형별로 확인할 수 있었으며, 유형별 특성을 통해서 에니어그램 배형 중소기업 경영자의 특성을 이 해하는데 기초 자료를 제공하였다는 점에서 의의가 있다.

Conventional wastewater treatment plants (WWTPs) do not fully remove micropollutants. Enhanced treatment of sewage effluents is being considered or implemented in some countries to minimize the discharge of problematic micropollutants from WWTPs. Representative enhanced sewage treatment technologies for micropollutant removal were reviewed, including their current status of research and development. Advanced oxidation processes (AOPs) such as ozonation and UV/H2O2 and adsorption processes using powdered (PAC) and granular activated carbon (GAC) were mainly discussed with focusing on process principles for the micropollutant removal, effect of process operation and water matrix factors, and technical and economic feasibility. Pilot- and full-scale studies have shown that ozonation, PAC, and GAC can achieve significant elimination of various micropollutants at economically feasible costs(0.16-0.29 €/m3). Considering the current status of domestic WWTPs, ozonation and PAC were found to be the most feasible options for the enhanced sewage effluent treatment. Although ozonation and PAC are all mature technologies, a range of technical aspects should be considered for their successful application, such as energy consumption, CO2 emission, byproduct or waste generation, and ease of system construction/operation/maintenance. More feasibility studies considering domestic wastewater characteristics and WWTP conditions are required to apply ozonation or PAC/GAC adsorption process to enhance sewage effluent treatment in Korea.

이 연구의 목적은 코칭 기법을 활용한 창의적 문제해결 수업모형을 개발 하 는 데 있다. 연구 방법은 창의적 문제해결 수업모형 초안을 구안하고 전문가 검 증을 통해 수업모형 최종안을 도출하였다. 최종안에 대해서는 창의적 문제해결 강의 경험이 있는 기업체 교수자와 교육학 박사학위 소지자 전문가를 대상으로 수업모형 타당화를 검증하였다. 수업모형 초안과 비교해 최종 수업모형은 코칭 기법을 창의적 문제해결 모형의 각각 단계에서 적용하고, 창의적 문제해결 기법 에 중점을 둔 모형이 개발되었다. 본 연구에서 개발된 창의적 문제해결 수업모 형은 기업체 대상 창의적 문제해결 교육을 위한 수업모형을 제공함으로써 창의 적 문제해결 교육을 도입하는 교수자에게 도움을 줄 수 있으며 체계적으로 교육 이 가능할 것으로 기대한다.

목적 : 본 연구는 상지근력 저하로 인해 일상생활 활동 수행이 제한되는 근육병 장애인을 대상으로 Arm Support 사용에 따른 작업 부하의 변화와 심리·사회적 영향을 알아보고자 하였다. 연구방법 : 연구 대상자는 지역사회에 거주하는 근육병 장애인 3명으로, 모두 척수성 근위축증을 진단받았다. 대상자는 능 동형 Arm Support 적용 전·후에 식사, 마스크 착용, 머리 빗기 활동을 수행하였다. 이후, NASA-TLX를 통해 능동형 Arm Support 적용 전·후 활동의 작업 부하를 측정 및 비교하였으며, 한국판 보조공학기기 심리·사회적 영향 척도 (K-PIADS)를 활용하여 Arm Support의 심리·사회적 영향력을 측정하였다. 마지막으로, 인터뷰를 통해 기기 사용 후 느낀 주관적인 감정 등에 대해 알아보았다. 결과 : 작업 부하 변화는 Arm Support 적용 후에 모든 항목의 평균 점수가 감소하였으며, 신체적 요구도 항목의 평균 점수가 가장 많이 감소하였다. 심리·사회적 영향 측정 결과는 하위 영역인 자기욕구 실현능력 2.08점(‘긍정적인 영향 ~ 매우 긍정적인 영향’), 적응성 2.06점(‘긍정적인 영향 ~ 매우 긍정적인 영향), 자존감 1.71점(’다소 긍정적인 영향 ~ 긍정 적인 영향‘)이었다. 인터뷰를 통해, 대상자는 Arm Support 사용함으로써 활동 수행 시 자신감, 만족감, 편안함 등을 느 꼈지만, Arm Support 구조가 정확하게 고정되지 않거나 휠체어 구조물의 간섭으로 인해 불편함 또한 느낀 것을 확인하 였다. 결론 : 본 연구를 통해 Arm Support가 근육병 장애인의 작업 부하를 낮추며, 긍정적인 심리·사회적 영향을 미치는 점 을 알 수 있었다. 추후에는 다양한 유형의 근육병 장애인을 대상으로 실생활 기반의 연구가 진행되어야 할 것이며, 체계 적인 평가를 통해 맞춤형의 서비스가 이루어져야 할 것이다. 본 연구의 결과가 Arm Support를 중재 전략으로 활용하는 연구와 서비스에 기초자료로 활용되기를 기대한다.