Polyethylene and polystyrene are frequently used resins for making food container including cup noodle bowls. In the pre-sent study, we investigated the potential risks of polyethylene and polystyrene cup noodle containers by cytotoxicity tests such as agar diffusion assay, filter diffusion assay, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. We exposed CCL-1 mouse fibroblast cell line to the polyethylene and polystyrene cup noodle containers indirectly through agar gel. We also used eluents derived from the cup noodle containers by storing them for 24 h at 70℃ in liquids, such as distilled water or dimethylsulfoxide (DMSO). Both polyethylene and polystyrene cup noodle container specimen were found to be non-cytotoxic in agar diffusion assay as well as filter diffusion assay. The eluents from polystyrene using DMSO showed slight cytotoxicity in MTT assay.

Wheel tracking test and ice pull-out test were performed in laboratory on dense grade asphalt mixture and asphaltmixture including 2.5% of 19mm PE aggregates. Meanwhile, temperature change, thermal conductivity, and snow meltingspeed were measured for both dense grade asphalt and PE aggregate mixed asphalt pavement via field testing on a testroad. Laboratory test results show that dynamic stability was improved and ice was removed easily by mixing PEaggregates in an asphalt mixture. Moreover, the existence of PE aggregates enhances heat insulation and snow meltingspeed due to the lower thermal conductivity compared to ordinary dense grade asphalt mixtures.

This study was conducted to find out the optimum composition of nursery soil for raising seedling of ginseng (Panax ginseng C. A. Meyer). Total 9 kinds of raw materials were used such as peat-moss, perlite, leaf mould, rice bran, gull's guano, castor-oil plant bark, palm bark, cow manure and chicken manure for optimum composition of nursery soil in ginseng. Occurrence of damping-off in ginseng was lowered about 50% in nursery soil type 1, 2 and 4 than in other types nursery soil in June, and occurrence rate of rusty root also lowest in nursery soil type 1. As the salinity of nursery soil increased, so did the occurrence of physiological disorder in ginseng seedling. The cause of salinity increasing in nursery soil has closely relation to NO3-N, P2O5 and Na+ content. Plant height, root length, diameter and weight were longer and heavier in nursery soil type 1 (mixing ratio of peat-moss, perlite and leaf mould was 50 : 20 : 30 based in volume) than in other types of nursery soil. So nursery soil type 1 was selected for raising seedling of ginseng. pH and electric conductivity (EC) of selected nursery soil type 1 was 5.55 and 0.13 dS/m. Contents of NO3-N and P2O5 were 21.0 and 40.0 mg/L, and K+ 0.36, Ca2+ 3.38, Mg2+ 2.01 and Na+ 0.09cmol+/L, respectively.

Polyethylene glycol (PEG) solution is currently used to prepare the colon before colonoscopy. Hyponatremic encephalopathy is a condition with neurologic symptoms such as headache, vomiting, confusion, seizure, and sometimes respiratory arrest. A 55-year-old woman presented to our emergency department with generalized tonic-clonic seizure and mental change after ingestion of PEG solution 2 L with water. Serum sodium concentrations was 115 mmol/L. After correction with hypertonic saline for 12hrs, serum sodium concentration reached 129 mmol/L and mental status recovered. We experienced a case of acute hyponatremic encephalopathy resulting from ingestion of PEG solution 2 L for colonoscopy.

In this study, thermoplastic starch (TPS), cross-linked starch (CS), and cross-linked starch modified with glycerol (CTPS) were prepared, and the mechanical properties of the compatibilized low-density polyethylene (LDPE) blends (LDPE/TPS, LDPE/CS, and LDPE/CTPS) were investigated and compared with those of uncompatibilized LDPE/TPS, LDPE/CS, and LDPE/CTPS blends. Maleic-anhydride-grafted polyethylene was used as the compatibilizer. The enhanced tensile strength and elongation at break for the compatibilized LDPE/modified starch blends are a result of the improved compatibility between LDPE and the modified starch, which was confirmed by torque measurements and scanning electron microscopy.

This research evaluated the environmental impact of polyethylene water supply pipe which is a target of voluntary agreement by Waste Charge System using Life Cycle Assessment (LCA). When analyzing the contribution of each impact category to the environmental score, resource depletion had the highest contribution at 57% and it was followed by global warming with 35% of contribution. Amongst the entire process and stage, production of raw materials, production of goods and disposal had about 60%, 18% and 18% of contribution, respectively. For resource depletion which was found to have the highest contribution, production of raw materials, production of goods and disposal accounted for nearly 77%, 11% and 7% of it, and the impact category of resource depletion which belongs to production of raw materials accounted for nearly 44% of the whole environmental score. Here, it was found that 88% of it resulted from crude oil. When analyzing the contribution of each stage to global warming that is the key issue of low carbon green growth, then, production of raw materials, production of goods and disposal showed around 38%, 29% and 28% of contribution, respectively. As the result, production of goods and disposal had higher contributions than resource depletion. Electricity used for production of goods is the major cause of global warming, and electricity used in the recycling process and incineration occupied about 65% and 36% of the disposal stage. In conclusion, we need to seek for plans to reduce the use of electricity through optimization of energy use during the production of goods and disposal, in order to establish an environmental and economical competitiveness of PE-related enterprises that are operated on a small scale.

변형경화형 시멘트 복합체(SHCC)는 직접인장 상황에서 FRCCs에 비해 우수한 변형경화 특성을 갖는 재료이다. 하지만 SHCC는 일반적인 콘크리트에 비해서 시멘트비율이 높은 부배합 이며, 이에 따라서 자기수축이 큰 특성을 갖는 재료이다. 따라서 시멘트 복합체 내에 팽창재를 대체함으로써 수축저감을 통한 성능향상을 기대하였다. 이 연구에서는 각 강도별 SHCC의 배합에 팽창재를 대체함에 따른 역학적특성을 평가하고자 하였다. 시험결과 설계기준 압축강도 70MPa 배합이 압축, 인장, 휨, 시험에서 우수한 역학적 특성을 나타내었으며, 균열 특성에서는 팽창재를 대체한 SHCC가 균열분산 및 연성에서 우수한 특성을 나타내었다.

김치를 기체 투과도가 조절된 플라스틱 용기, 시유옹기, 유리병을 사용하여 각각 발효하였을 때, 그 품질특성이 어떻게 변화하는지를 에서 8주간 발효하면서 관찰하였다. 다른 용기에 보관한 김치에 비해, 투과도 조절 플라스틱 용기에 보관한 김치의 pH 감소가 적었으며, 산도 역시 8주 후에 0.99로 나타나 증가율이 가장 적게 나타났다. 미생물수의 변화를 보면 투과도 조절 플라스틱 용기에 보관한 김치가 총균수의 증가는 적고, 유산균의 증가는 높게 나타

본 연구의 목적은 저열 시멘트를 활용한 콘크리트와 고밀도 폴리에틸렌을 활용한 친환경 저수조를 평가하는 것이다. 친환경 저수조의 강도와 파괴모드를 평가하기 위하여 콘크리트와 고밀도 폴리에틸렌 복합체의 인장강도 시험, 다양한 종류의 콘크리트 수화열 실험, 다양한 혼화재를 활용한 수화열 실험 등을 수행하였다. 수행결과 전단키가 콘크리트와 고밀도 폴리에틸렌의 복합체로 거동할 수 있는 중요한 역할을 한다는 것을 규명하였고, ㄱ 타입의 전단키가 V 타입보다 40% 이상 인장강도를 증진시킨다는 것을 보여주었다. 연구결과 새로운 친환경 저수조는 기존의 콘크리트 저수조보다 안전성을 개선시키며, 보다 적용성과 활용성이 많은 것으로 기대된다.

This pilot study evaluated fueling feasibility of sewage sludge, which contains a large amount of water content, by applying melting of thermoplastic polyethylene (PE). This study has identified a simultaneous achievement of drying and heating value improvement of the sewage sludge. The sewage sludge collected from a sewage sludge treatment plant during a winter period had a water content of 83.7 wt%, a combustible volatile content of 12.5 wt%, and an ash content of 3.8 wt%. The higher heating value (HHV) of the dried sewage sludge, before impregnation or coating of PE, was 4,600 kcal/kg. The collected sewage sludge was immersed into the melted PE solution, which had a HHV of 11,070 kcal/kg, and kept immersing with increasing reaction time. As the reaction (immersing or coating or impregnation) time increased, the water content of the sludge decreased. However, the HHV of the sludge increased with increasing the reaction time. The HHVs of the sewage sludge immersed or dipped into the melted PE solution for 15 min ranged from 6,780 to 8,170 kcal/kg with water content less than 7 wt%. This result indicates the melted PE solution can be utilized as an improvement technology for dryness and heating value of the sewage sludge with high water content. The sewage sludge impregnated or coated with melted PE can be utilized as potential fuel or energy resources.

0%, 5%, 10%의 염수로 절인배추를 각각 High density polyethylene film (HDPE-film), Low density polyethylene film (LDPE-film), Mirafresh film (MF-film)으로 포장한 후 4주간 에 저장하면서 pH, 염도, 총균수, 젖산균수, 탄력성을 측정해 품질특성의 변화를 평가하였다. pH의 경우 절이지 않은 배추(0% 염수)일 때는 필름별로 큰 차이를 보이지 않았고,

The activated sludge obtained from wastewater coke oven plant was immobilized by entrapment with polyethylene glycol (PEG). The effects of several factors on the biodegradation of CN- from synthetic wastewater were investigated using batch and continuous reactors. The degradation rate of CN- increased with increasing of the immobilized bead volume in the reactor. Approximately 7.65 mg/L of NH4-N was produced upon the degradation of 35 mg/L of CN-. When high concentrations of the toxic cyanide complex were used in the testing of cyanide degradation, the free activated sludge could be inhibited more than that of the immobilized activated sludge. When the phenol concentration was higher than 400 mg/L in the synthetic wastewater, approximately 98.4% of CN- was removed within 42 hours by the immobilized activated sludge. However, the cyanide was not completely degraded by the free activated sludge. This indicates that high phenol concentrations can act as a toxic factor for the free activated sludge. A CN- concentration of less than 1 mg/L was achieved by the immobilized sludge at the loading rate of 0.025 kg CN-/m3-d. Moreover, it was found that the HRT should be kept for 48 hours in order to obtain stable treatment conditions.

인삼 4년생을 대상으로 해가림 색상을 달리하여 재배 시험한 결과, 대조구인 4중직 PE 차광망(청색 3 + 흑색 1중직)이나 청색 4중직 차광망에서 재배된 인삼의 뿌리 근중은 적색 4중직 차광망보다 높게 나타났으며, 대조구보다 청색과 적색에서 동체의 비율이 낮고 지근의 비율이 높아 투광량이 많아지면 동체의 생장이 감소하고 지근의 생장은 증가하였다. 뿌리에 함유된 진세노사이드 함량은 적색 해가림재배에서 가장 높게 나타나 투광량이 증가할수록 진세노사이드 함량이 증가되었으며, 특히 진세노사이드 Rg1의 함량이 유의적으로 더 높았다. 색상에 따른 진세노사이드 함량차이는 해가림 색상 차이에 의해 생합성 과정이 영향을 받은 것이 아닌 생육량의 차이에 따른 결과로 판단되었다.

The use of support materials on the nanoparticle synthesis and applications has advantages in many aspects; resisting the aggregation and gelation of nanoparticles, providing more active sites by dispersing over the supports, and facilitating a filtering process. In order to elucidate the influence of the supports on the nitrate reduction reactivity, the supported iron nanoparticles were prepared by borohydride reduction of an aqueous iron salt in the presence of supports such as activated carbon, silica and polyethylene. The reactivity for nitrate reduction decreased in the order of unsupported Fe(0) > activated carbon(AC) supported Fe(0) > polyethylene(PE) supported Fe(0) ≥ silica supported Fe(0). Rate constants decrease with increasing initial nitrate concentration implying that the reaction is limited by the surface reaction kinetics.

청색과 황색의 4중직 폴리에틸렌 차광망을 해가림 피복물로 사용하여 해가림 색상이 4년생 인삼의 생육 및 진세노사이드 함량에 미치는 영향을 구명하고자 시험한 결과는 다음과 같다. 1. 청색 차광망의 spectral irradiance는 498nm에서, 황색차광망은 606nm에서 최고를 보여 색상에 따라 광질은 뚜렷한 차이를 보였다. 2. 청색 차광망은 황색 차광망보다 투광량이 23% 더 많았으며,기온도 0.3 ˚C 더 높았고 여름철 투광량 증가로 인한 기온 상승으로 황색 차광망보다 지상부 생육이 억제되고 고온장해 발생이 심하였다. 3. 황색 차광망은 청색 차광망보다 엽록소 함량이 더 많고 경장 및 엽면적이 더 컸으며, 고온장해 발생율이 낮아 인삼수량은 48% 증가되었다. 4.동체부위의 총 진세노사이드 함량은 색상 간에 유의적인차이가 없었으나 지근 및 세근부위의 총 진세노사이드 함량은 청색 차광망이 황색 차광망보다 유의적인 증가를 보였다. 5. PD/PT비율은 지근부위에서만 청색 차광망이 황색 차광망보다 유의적으로 높았으며, Rb1/Rg1의 비율은 모든 부위에서 청색 차광망이 황색 차광망보다 높았으나 지근부위에서는 유의성이 없었다.

This study was carried out to investigate spectral irradiance characteristics of blue, yellow, and blue-black colored polyethylene (PE) shading net and the effect on growth characteristics and yield in ginseng seedling. The spectral irradiance (μmol/m2/s/nm) showed the peak at 498 nm in both of blue and blue-black PE shading net, and 606 nm under yellow PE one. The intensity of blue light in blue shading was more strong than that of blue-black shading, control. Blue shading was increased by 17% and 23% in accumulated quantum for daytime, 0.5℃ and 0.2℃ in maximum temperature on June 2 than that of yellow and blue-black shading, respectively, but heat injury ratio of the former was lower than that of the latter. Chlorophyll content and stem length in blue shading were decreased more significantly than those of yellow and blue-black shading. The specific leaf weight was higher under blue and yellow shading than that of blue-black shading. Ginseng seedling harvested in blue shading was increased by 13~17% in the number of root, and 17~20% in root weight per m 2 compared to yellow and blue-black shading owing to the increase of survived plant, and the decrease of specific leaf weight, heat injury ratio, and stem length.

본 실험은 오리엔탈 나리 ‘Siberia’ 품종을 유공비닐 봉지에서 인편삽시 인편 착생부위와 삽목조건에 따른 소인경의 형성과 생장을 조사하여 효과적인 소인경 생산 방법을 알아보고자 실시하였다. 착생부위에 있어서 내부보다는 외부와 중부인편이 소인경의 형성 및 생육이 양호하였다. 삽상의 온도는 15℃나 30℃보다 20℃와 25℃ 조건에서 소인경의 무게, 둘레, 높이, 수가 증가하였다. 용토 1L당 수분 400mL 처리는 타처리에 비해 소인경의 무게와 직경이 16% 정도 증가한 것으로 나타났다. 피트모스 단용과 피트모스:펄라이트:버미큘라이트를 1:1:1 혼합한 용토에서 소인경 생육이 양호하였다. 인편과 용토의 비율을 1:2하여 혼합한 후 인편삽을 하더라도 소인경 무게와 직경에는 큰 차이가 없었다.

제올라이트 함유 폴리에틸렌 필름의 최대응력, 파단신율 및 인열강도를 측정한 결과 전반적으로 금속이온으로 치환한 제올라이트 필름에 비해 계면활성제로 치환한 제올라이트를 함유한 필름의 물성이 순수 LDPE필름의 물성에 비해 큰 감소 없이 일정하게 유지되는 사실을 확인하였다. 한편 선도유지기능 실험 결과 일부의 양이온성(Al 및 Ag) 또는 계면활성제로 개질된 제올라이트 필름들이 시험된 과채류에 대하여 일반 LDPE 포장용 필름보다 우수한 선도유지기능