• 제목/요약/키워드: Surface Mat

검색결과 223건 처리시간 0.022초

그라인딩 처리 횟수에 따른 나노피브릴화 셀룰로오스 매트의 공극 특성 (Effect of the Number of Passes through Grinder on the Pore Characteristics of Nanofibrillated Cellulose Mat)

  • 심규정;류재호;윤혜정
    • 펄프종이기술
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    • 제45권1호
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    • pp.35-41
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    • 2013
  • In this study, we investigated the effect of the number of passes through agrinder on the pore characteristics of nanofibrillated cellulose (NFC) mat. The beaten pulp suspension was used to make NFC suspension using a grinder. To evaluate the pore characteristics of a NFC mat, the surface morphology of the dried NFC mat was observed with FE-SEM and the specific surface area was analyzed with BET nitrogen gas adsorption. The structure of NFC mat was changed with the different number of passes and drying methods. The specific surface area of NFC mat increased with the increase in the number of passes. The 20-passed NFC mat had 20 times larger specific surface area ($141m^2/g$) compared to the 0-passed NFC mat. The specific surface area was strongly correlated with the average pore size in NFC mat. The average pore diameter in NFC mat was calculated from the gas sorption isotherms using BJH model. The value was 13 - 15 nm, indicating that the NFC mat had mesoporous structure.

Characteristics of Surface Strand Orientation and Strand Mat Thickness Variation and Its Effect on the Bending Properties of Commercial OSB

  • Oh, Sei Chang
    • Journal of the Korean Wood Science and Technology
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    • 제36권2호
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    • pp.56-62
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    • 2008
  • The surface and edge structure of OSB is defined by surface strand orientation and strand mat thickness variation parallel to the length of the panel using video-microscope. The bending strength of OSB was correlated with surface strand orientation and decreased with increasing the orientation angle in the direction parallel to length of the panel. Average strand mat thickness variation parallel to the length of the panel did not influence the bending strength, but the bonding characteristics among the outermost strands affects the bending strength of OSB. Hankinson formula can be used to predicts the MOE according to strand orientation in the surface of OSB, and more precise strand alignment and reducing thickness variation should be important in the structural performance of OSB panels.

필라테스 매트 운동과 불안정 지지면 운동이 65세 이상 노인의 균형에 미치는 영향 (The Effect of Pilates Mat Exercise and Instability Support Surface Exercise on Balance for the Elderly Person Aged 65 or More)

  • 이채우;김현수;배원식
    • 대한통합의학회지
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    • 제2권3호
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    • pp.75-82
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    • 2014
  • Purpose : The purpose of this study was to investigate the effect of pilates mat exercise (PME) and instability support surface exercise (ISSE) for TUG (Time up & go) and static balance in the elderly person aged 65 or more. Method : 30 subjects in Y-equestrian were randomly divided two group, pilates mat exercise (PME) group and instability support surface exercise (ISSE) group. Each group carried out 40 minutes exercise two times a week for 12 weeks. TUG (Time up & go) and Biorescue were measured for static balance. Result : The results were as follows, the TUG between pilates mat exercise (PME) group and instability support surface exercise (ISSE) group in post-test, were significantly different in measures (p<.05). And there were significant in two group after exercise (p<.05). The static balance between pilates mat exercise (PME) group and instability support surface exercise (ISSE) group in post-test, were significantly different in measures (p<.05). And there were significant in two group after exercise (p<.05). Conclusion : These finding revealed that pilates mat exercise was effective on TUG and static balance in the elderly person aged 65 or more so that these exercise can be new alterative exercise for obesity management in the elderly person.

Improved Electrical Conductivity of a Carbon Nanotube Mat Composite Prepared by In-Situ Polymerization and Compression Molding with Compression Pressure

  • Noh, Ye Ji;Kim, Han Sang;Kim, Seong Yun
    • Carbon letters
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    • 제13권4호
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    • pp.243-247
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    • 2012
  • A fabrication method to improve the processability of thermoplastic carbon nanotube (CNT) mat composites was investigated by using in-situ polymerizable and low viscous cyclic butylene terephthalate oligomers. The electrical conductivity of the CNT mat composites strongly depended on the compression pressure, and the trend can be explained in terms of two cases, low and high compression pressure, respectively. High CNT mat content in the CNT mat composites and the surface of the CNT mat composites with fully contacted CNTs was achieved under high compression pressure, and direct contact between four probes and the surface of the CNT mat composites with fully contacted CNTs gave resistance of $2.1{\Omega}$. In this study the maximum electrical conductivity of the CNT mat composites, obtained under a maximum applied compression pressure of 27 MPa, was 11 904 S $m^{-1}$, where the weight fraction of the CNT mat was 36.5%.

야채재배 밭에서 지표피복의 비점오염원 저감효과 (Effect of Surface Cover on the Reduction of NPS Pollution at a Vegetable Field)

  • 신민환;장정렬;원철희;최용훈;신재영;임경재;최중대
    • 한국물환경학회지
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    • 제28권3호
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    • pp.436-443
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    • 2012
  • This research was focused on the effect of rice straw and rice straw mat on the reduction of upland field non-point source (NPS) pollution discharges. Six experimental plots of $5{\times}22m$ in size and 3% in slope prepared on gravelly sandy loam soil were treated with control, rice straw cover and rice straw mat cover. Radish in Spring growing seasons were cultivated. NPS pollution discharge was monitored and compared with respect to the treatments. The surface cover rate of rice straw and rice straw mat right after the treatments was 64.7% and 73.7%, respectively. Rainfall of the 16 monitored events ranged from 12.8 mm to 538.2 mm. Runoff coefficient of the events was 0.01~0.67 in control plot, 0~0.63 in rice straw plot and 0~0.45 in rice straw mat plot. The reduction of runoff compared to the control plot was 5.4~99.7% in rice straw plot and 32.9~100% in rice straw mat plot. The reduction of NPS pollution load was 52.0% for SS, 28.5% for T-N and 35.2% for T-P in rice straw plot and 79.8% for SS, 68.3% for T-N and 53.3% for T-P in rice straw mat plot. This research revealed that rice straw mat cover on the soil surface could not only increase the crop yield and farmer's income but also reduce the NPS pollution loads significantly.

콘크리트매트를 이용한 개착식 지반공동 복구방법에 관한 연구 (A Study on the Open Cut Restoration of Underground Cavity Using Concrete Mat)

  • 박정준;신희수;정윤석;유승경;홍기권
    • 한국지반신소재학회논문집
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    • 제18권1호
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    • pp.55-65
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    • 2019
  • 본 연구에서는 최근 발생빈도가 증가하고 있는 지반함몰의 가장 큰 영향요소인 지중 공동에 대하여 콘크리트매트를 이용한 개착식 복구방법의 보강효과 분석을 위한 실험적 및 수치해석적 연구를 수행하였다. 먼저, 평판재하시험을 이용하여 지표로부터 10cm, 20cm, 30cm의 보강깊이에 대하여 콘크리트매트 보강에 따른 응력감소율을 평가한 결과, 약 60%의 응력감소 효과를 나타내었다. 또한 실내실험과 수치해석 결과를 이용하여 지반침하량과 응력감소율을 분석한 결과, 콘크리트매트 설치깊이가 지표로부터 10cm~20cm 깊이에서 보강효과가 우수한 것으로 확인되었다. 지반변형계수 측정을 위한 LFWD실험 결과, 콘크리트매트가 지표로부터 20cm의 깊이에 보강되었을 때의 변형계수가 가장 크게 나타났다. 따라서 지중 매설물 손상에 의한 지중공동이 포장체 하부까지 높이 방향으로 발달한 경우, 지표로부터 20cm 이내에 콘크리트 매트를 보강하는 것이 효과적인 것으로 분석되었다.

배추와 무밭에서 발생하는 비점오염원 저감을 위한 피복재와 토양개량제 적용 (Application of Surface Cover Materials and Soil Amendments for Reduction of Non-Point Source Pollution from Upland Fields)

  • 신민환;장정렬;신현준;금동혁;최용훈;원철희;임경재;최중대
    • 한국농공학회논문집
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    • 제55권4호
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    • pp.21-28
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    • 2013
  • The objective of the study was to investigate the effect of rice straw mat, rice straw mat with PAM (Polyacrylamide) and gypsum addition on surface runoff and sediment discharge in field. Six experimental plots of $5{\times}22m$ in size and 3 % in slope prepared on gravelly sandy loam soil were treated with control, rice straw mat cover with gypsum and rice straw mat cover with gypsum and PAM. Radish in Spring and Chinese cabbage in autumn growing seasons were cultivated. Non point source (NPS) pollution discharge was monitored and compared among the treatments. Rainfall of the 10 monitored events ranged from 17.0 mm to 93.5 mm. Runoff coefficient of the events was 0.005~0.239 in control plot, 0~0.176 in rice straw plot with gypsum and 0~0.046 in rice straw mat plot with gypsum and PAM. When compared to the control plot, the runoff amount was reduced by 10.4~100 % (Ave. 60.8) in rice straw plot with gypsum and 80.7~100 % (Ave. 96.7 %) in rice straw mat plot with gypsum and PAM. The reduction of NPS pollution load was 54.6 % for BOD5, 71.5 % for SS, 41.6 % for TN and 61.4 % for T-P in rice straw with gypsum plot and 91.9 % for BOD5, 92.0 % for SS, 88.0 % for TN and 88.5 % for T-P in rice straw mat with gypsum and PAM plot. This research revealed that rice straw mat cover with soil amendments on the soil surface could not only increase the crop yield but also reduce the NPS pollution loads substantially.

경사지 밭에서 발생하는 토양유실 저감을 위한 피복재 적용 (Surface Cover Application for Reduction of Runoff and Sediment Discharge from Sloping Fields)

  • 신민환;원철희;박운지;최용훈;신재영;임경재;최중대
    • 한국농공학회논문집
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    • 제53권6호
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    • pp.129-136
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    • 2011
  • To measure effects of surface cover on runoff and sediment discharge reduction using rainfall simulator, four(5 m${\times}$30 m scale) plot experiments were conducted in this study. Surface covers made with straw mat, Polyacrylamide (PAM), chaff, and sawdust were simulated 4 times under 31.1~44.4 mm/hr rainfall intensities. Compared with results from control plot, the time of runoff generation is delayed and outflow volume decreased with surface cover. Effects on runoff reduction of straw mat, PAM, sawdust and chaff ranged 4.7~81.5 % and runoff rate reduced by 6.5~76.1 % respectively, when compared with those from control plot. The percentage of decrease in sediment discharge were 99.7~99.8 % from straw mat+sawdust+PAM plots, 85.9~95.6 % from straw mat+PAM plots, and 98.5~99.4 % from straw mat+chaff+PAM plots. The runoff, sediment discharge, and SS concentration reduction efficiencies of the cover materials were outstanding when compared to control plot. It was analyzed that reduction of runoff and sediment discharge were mainly contributed by decrease in rainfall energy impact and flow velocity and increase of infiltration due to the surface cover materials. The results could be used as a base for the development of best management practices (BMPs) to reduce runoff, sediment discharge from sloping field.

지표피복재 적용을 통한 비점오염원 저감효과 분석 (Analysis of the Reduction Effect on NPS Pollution Loads by Surface Cover Application)

  • 신민환;원철희;박운지;최용훈;장정렬;임경재;최중대
    • 한국농공학회논문집
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    • 제53권4호
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    • pp.29-37
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    • 2011
  • Effect of rice straw mat and wood shaves on the reduction of runoff and nonpoint source (NPS) pollution loads from field plots were experimentally studied. Three runoff plots of $5{\times}22$ m in size and 3 % in slope were prepared on a loamy sand field. Each plot was equipped with a flume to measure runoff and collect water samples. Experimental treatments of surface cover were bare, wood shaves (1,000 kg/ha) and rice straw mat cover (3,000 kg/ha). Under radish was cultivation. During the growing season of the radish, three rainfall-runoff events were monitored. Effect of wood shaves and straw mat cover on runoff reduction was 4~30 % and 33~75 % respectively compared to control. The effect on NPS pollution reduction was 36.8 and 64.3 % in BOD, 41.1 and 80.8 % in SS, 34.0 and 56.1 % in TP and 28.0 and 56.6 % in TN respectively. It was analyzed that the reduction of runoff and NPS pollution were mainly contributed by the decrease of rainfall energy impact and flow velocity and the increase of infiltration due to the surface cover materials. Rice straw mat showed very stable soil cover while large portion of wood shaves were lost during heavy storm events. It was concluded that straw mat was an efficient cover material to reduce NPS pollution from upland fields.