• Title/Summary/Keyword: EPS

Search Result 902, Processing Time 0.034 seconds

Isolation and Phylogenetic Characteristics of Exopolysaccharide Producing Bacteria in a Rhizosphere Soil of Medicinal Herbs (약초 근권토양 내 다당 생성세균 분리 및 계통학적 특성)

  • Lee, Hae-Ran;Kim, Ki-Kwhang;Whang, Kyung-Sook
    • Korean Journal of Microbiology
    • /
    • v.46 no.3
    • /
    • pp.278-285
    • /
    • 2010
  • We examined the distribution of exopolysaccharide (EPS) producing bacteria population in rhizosphere soils of domestic medicinal herbs; Angelica sinensis, Atractytodes japonica, Achyranthes japonica, Anemarrhena asphodeloides, and Astragalus membranaceus. Fifty-six percent of the total isolates from rhizosphere soil of Angelica sinensis were EPS producing bacteria, suggesting the dominance of EPS producing bacteria in rhizosphere soil of Angelica sinensis. EPS producing bacteria were enumerated in root system (rhizosphere soil, rhizoplane, inside of root) of Angelica sinensis. Bacterial density of rhizosphere soil, rhizoplane, and inside of root were distributed $9.0{\times}10^6CFU/g{\cdot}soil$, $7.0{\times}10^6CFU/g{\cdot}soil$, and $1.4{\times}10^3CFU/g{\cdot}soil$, respectively. EPS producing bacteria from rhizosphere soil were categorized into five major phylogenetic groups: Alphaproteobacteria (4 strains), Betaproteobacteria (6 strains), Firmicutes (2 strains), Actinobacteria (3 strains), and Bacteroidetes (1 strain) subdivisions. Also, the EPS producing isolates from rhizoplane were distributed as 7 strains in Alphaproteobacteria, 3 strains in Betaproteobacteria, 2 strains in Actinobacteria, 3 strains in Bacteroidetes, and 1 strain in Acidobacteria subdivisions. All of the EPS producing bacteria inside of root belong to genus Chitinophaga. Burkholderia caribiensis DR14, Terriglobus sp. DRP35, and Rhizobium hainanense SAP110 were selected in 112 EPS producing bacteria. These appeared to have produced high levels of exopolysaccharide 6,555 mpa.s, 3,275 mpa.s, and 1,873 mpa.s, respectively. The purified EPS was analyzed Bio-LC. As neutral sugars, glucose, galactose, mannose were detected and as amino sugars, galactosamine and glucosamine were detected. Especilally, analysis of Bio-LC showed that Rhizobium hainanense SAP110 produced glucose (60~89%) and glucosamine (8.5%) as major neutral sugar and amino sugar, respectively.

An Analytical Study of Flexible Pavement Design Using Resilient Modulus Model of Expanded Polystyrene (EPS) (EPS 회복탄성계수 모델을 이용한 연성포장설계의 해석적 연구)

  • Park, Ki-Chul;Chang, Yong-Chai
    • Journal of the Korean Geosynthetics Society
    • /
    • v.14 no.2
    • /
    • pp.35-44
    • /
    • 2015
  • The resilient modulus model of EPS geofoam to be used for a flexible pavement design was developed. In this study, the model was applied to design the flexible pavement and to predict the magnitude of the deformation of EPS geofoam blocks as a subgrade in the flexible pavement structure by using the resilient modulus model of EPS geofoam (RMEG) program. The RMEG program presented how much the EPS geofoam subgrade settled over the designed duration and the AASHTO flexible pavement design equation with the resilient modulus of EPS geofoam noted that how long the flexible pavement endured under traffic loads with 70% reliability for the estimated duration with less than 5mm vertical deformation during 20.6 years without the significant pavement distress as a substitute material for the natural soils.

Experimental and numerical investigation of expanded polystyrene (EPS) geofoam samples under monotonic loading

  • Khalaj, Omid;Siabil, Seyed Mohammad Amin Ghotbi;Azizian, Mehran;Tafreshi, Seyed Naser Moghaddas;Masek, Bohuslav;Kepka, Miloslav;Kavalir, Tomas;Krizek, Michal;Jirkova, Hana
    • Geomechanics and Engineering
    • /
    • v.22 no.6
    • /
    • pp.475-488
    • /
    • 2020
  • The recent increase in the use of Expanded Polystyrene (EPS) geofoam in construction and geotechnical projects has driven researchers to investigate its behavior, more deeply. In this paper, a series of experimental tests to investigate the stress-strain behavior and the mechanical properties of EPS blocks, under monotonic axial loading are presented. Four different densities of cylindrically shaped EPS with different dimensions are used to investigate the effects of loading rate, height and diameter, as well as the influence of the density of EPS on the stress-strain response. The results show that increasing the height of the EPS samples leads to instability of the sample and consequent lower resistance to the applied pressure. Large EPS samples show higher Young's modulus and compressive resistance due to some boundary effects. An increase in the rate of loading can increase the elastic moduli and compressive resistance of the EPS geofoam samples, which also varies depending on the density of the samples. It was also determined that the elastic modulus of EPS increases with increasing EPS density. By implementing an efficient numerical procedure, the stress-strain response of EPS geofoam samples can be reproduced with great accuracy. The numerical analysis based on the proposed method can used to evaluate the effect of different factors on the behavior of EPS geofoam.

Setting Behavior of Polystyrene Mortars with Elapsed Curing Time (폴리스티렌 모르타르의 양생재령에 따른 경화거동)

  • Choi Nak-Woon;Kim Han-Sang
    • Journal of the Korea Concrete Institute
    • /
    • v.16 no.1 s.79
    • /
    • pp.54-60
    • /
    • 2004
  • This study deals with the setting behavior of polystyrene mortars using waste expanded polystyrene(EPS) solution-based binders. The binders for polystyrene mortars are made by mixing crosslinking agent with EPS solutions prepared by dissolving EPS in styrene. Polystyrene mortars are prepared with various EPS concentrations of EPS solutions and crosslinking agent contents, subjected to a dry curing, and tested for working life, peak exotherm temperature and 10h-length change. From the test results, He working lives of polystyrene mortars are shortened with raising EPS concentration of EPS solution and crosslinking agent content. Low-shrinkage or non-shrinkage polystyrene mortars could be obtained by adjusting EPS concentration of EPS solution and crosslinking agent content.

Freshness Extension of Table Grape 'Sheridan' by Packaging Methods (포장방법에 따른 'Sheridan' 포도의 신선도 유지 효과)

  • 박형우;김동만
    • Food Science and Preservation
    • /
    • v.6 no.3
    • /
    • pp.260-263
    • /
    • 1999
  • This study was measured weight loss, total ascorbic acids, titratable acidity and soluble solids contents to investigate the effect of EPS(expended polystyrene foam) box. double wall corrugated paperboard box and LDPE film pouches during storage at 25$^{\circ}C$. The rate of weight loss was 5.7% in corrugated paperboard box after 10 days. but those of 20LD, 40LD film and EPS box were 1.0, 0.8, and 0.9%, respectively. Total ascorbic acid content and titratable acidity of EPS box was 15.0% and 24.4% higher than that in corrugated paperboard box, but the obvious differents were not observed among the LDPE film pouches and EPS box. The titratable acidity was decrease during storage, but total soluble solids content was slightly increase. Overall appearences of LDPE pouches and EPS box were boner than those of corrugated paperboard box.

  • PDF

Effect of Carbohydrates to Protein Ratio in EPS on Sludge Settling Characteristics

  • Shin, Hang-Sik;Kang, Seok-Tae;Nam, Se-Yong
    • Biotechnology and Bioprocess Engineering:BBE
    • /
    • v.5 no.6
    • /
    • pp.460-464
    • /
    • 2000
  • Extracellular polymeric substances (EPS) are believed to play a role in the binding and formation of microbial flocs. However, the precise role is not well known. Sludge settling characteristics and the carbohydrate to protein ratio in EPS were tested with various airflow rates in this study. Sludge was collected from three modified sequencing batch reactors (SBRs), which were operated at 16$\^{C}$ with an airflow rate of 0.8L/min, 3L/min and 6L/min, respectively. During the operation, the reactor operated at an airflow rate of 0.8L/min showed sludge volume index (SVI) of 80 to 90ml/g and a constant ratio of carbohydrate to protein in the EPS, while a significant increase in the SVI was seen in the other reactors. Sludge bulking increased the amount of carbohydrate in the EPS, while kept protein almost constant in the airflow rate of 3L/min ad 6L/min. Surface charge also increased with increases in the carbohydrate to protein ratio in the EPS, which weakens the attraction between the EPS and multivalent cations. The ratio of carbohydrate to protein in the EPS was tween the EPS and multivalent cations. The ratio of carbohydrate to protein in the EPS was inferred to be essential for bioflocculation.

  • PDF

Freshness Extension of 'Shingo' Pear Packed with Expandable Polystyrene Form Box (Expandable Polystyrene Box의 '신고' 배의 신선도 유지효과)

  • Park, Hyung-Woo;Park, Jong-Dae;Kim, Dong-Man;Lee, Myung-Hoon
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
    • /
    • v.4 no.2
    • /
    • pp.12-17
    • /
    • 1998
  • Weight loss of pear packed with corrugated paperboard box after 50 days storage at $20^{\circ}C$ was 4.4%, and those of 20LD, 40LD film and EPS box were 0.8-0.7%. Ascorbic acid content of EPS was 20% higher than that of control. Hardness of EPS was also similar trend. Titratable acid and total soluble solid content of pear were not different among the packages. Decay of control was 1-2 pieces per box, but the others was not found. Overall appearences of LD, CE and EPS were better than that of control.

  • PDF

Freshness Extension of ‘Fuji’Apple to Packaging materials (포장재가 ‘후지’사과의 신선도에 미치는 영향)

  • 박형우;박종대;김동만;최주섭
    • Food Science and Preservation
    • /
    • v.8 no.4
    • /
    • pp.345-350
    • /
    • 2001
  • This study was measured weight loss, total ascorbic acid, titratable acidity, and soluble solids content to investigate the effect of EPS(expanded polystyrene foam, foaming rate 55 times V/W) box, LDPE film pouches and double wall corrugated fiberboard box during storage at 20$\^{C}$. Weight loss of apple packed with corrugated paperboard box after 40 days storage was 5.7%, arid those of LDPE, CE(zeolited coated film) film and EPS box were 0.2-0.5%. Ascorbic acid content of apple packed with LDPE, CE, EPS was higher than that of control. Titratable acidity and total soluble solid content of control were changed 40% and 10%, but the EPS were changed 27% and 4%, respectively. Overall appearances of ‘Fuji’apple packed with LDPE, CE and EPS were better than that of control.

  • PDF

Case Studies of EPS Failure and Quality Control by Site Monitoring (EPS 공법의 파괴사례 및 품질관리 개선방안)

  • 김호비;주태성;류기정;한태곤;김태경;정종권
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2003.03a
    • /
    • pp.401-408
    • /
    • 2003
  • EPS(Expanded Polystyrene) has been used in a variety of applications as a solution of difficult soil conditions encountered in construction activities. Although there has been significant worldwide growth in the use of EPS as a lightweight fill material, it has a few failure cases before and after the construction. This paper described the observed failures of EPS structures up In date around the world. Also, method of quality control was proposed for site monitoring.

  • PDF