• 제목/요약/키워드: Transmission ecology

검색결과 63건 처리시간 0.02초

Measurement of Sound Transmission Loss in a Sound Barrier Filled with the Rice-Straw Particles by the Transfer Function and Laboratory Measurement Methods

  • Kang, Chun-Won;Jang, Eun-Suk;Jang, Sang-Sik;Kang, Ho-Yang
    • Journal of the Korean Wood Science and Technology
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    • 제46권4호
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    • pp.338-345
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    • 2018
  • The sound insulation capacity of a barrier is indicated by its transmission loss. In this study, the sound transmission loss of a sound barrier filled with rice-straw particles was measured by the transfer function method and a laboratory measurement method. The results of the two measurements were compared. The transmission losses measured by the two methods were similar above a frequency of 500 Hz. The loss increased greatly upon the introduction of a plywood to the sound barrier. The results of this study are expected to be used to design sound barriers for roads.

Morphological and Molecular Characterization of Lymnaeid Snails and Their Potential Role in Transmission of Fasciola spp. in Vietnam

  • Dung, Bui Thi;Doanh, Pham Ngoc;The, Dang Tat;Loan, Ho Thi;Losson, Bertrand;Caron, Yannick
    • Parasites, Hosts and Diseases
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    • 제51권6호
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    • pp.657-662
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    • 2013
  • Freshwater snails of the family Lymnaeidae play an important role in the transmission of fascioliasis worldwide. In Vietnam, 2 common lymnaeid species, Lymnaea swinhoei and Lymnaea viridis, can be recognized on the basis of morphology, and a third species, Lymnaea sp., is known to exist. Recent studies have raised controversy about their role in transmission of Fasciola spp. because of confusion in identification of the snail hosts. The aim of this study is, therefore, to clarify the identities of lymnaeid snails in Vietnam by a combination of morphological and molecular approaches. The molecular analyses using the second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA clearly showed that lymnaeids in Vietnam include 3 species, Austropeplea viridis (morphologically identified as L. viridis), Radix auricularia (morphologically identified as L. swinhoei) and Radix rubiginosa (morphologically identified as Lymnaea sp.). R. rubiginosa is a new record for Vietnam. Among them, only A. viridis was found to be infected with Fasciola spp. These results provide a new insight into lymnaeid snails in Vietnam. Identification of lymnaeid snails in Vietnam and their role in the liver fluke transmission should be further investigated.

성인 남녀의 투습방수소재 스포츠 웨어의 소재별 착용감에 관한 연구 (The Wearing Sensation of Men and Women in Sports Wear with Waterproof and Water Vapor Permeable Fabrics)

  • 조지현;류덕환
    • 한국생활과학회지
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    • 제9권1호
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    • pp.47-61
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    • 2000
  • The purpose of this study was to examine the performance and properties of sports wear that have the excellent wearing sensation and are in harmony with the functions of human bodies. With four kind(sample A, B, C, D) of materials which have different water vapor transmission, the physiological responses of human bodies and the changes of subjective sensations were studied through the actual aerobic sports program at $20^{\circ}C$, 60%R.H. The forehead temperature had the minimal variation among the local skin temperatures. The fabrics of low water vapor transmission demonstrated high breast temperature. There are significant differences among materials depending on the humidity in clothes(especially back and breast), which was about 6 % for breast and about 14 % for back. The order of loss in body weight was in the opposite direction to that of water vapor transmission for each material.

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투습발수직물과 보온단열소재의 열 및 수분전달 특성 (Thermal and Water Transmission Properties of Vapor Permeable Water Repellent Fabrics and Thermal Insulation Batting Materials)

  • 조길수;최종명;이정주;이선우
    • 한국의류학회지
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    • 제16권2호
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    • pp.237-244
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    • 1992
  • The purpose of this study was to comparatively evaluate thermal and water transmission properties of several vapor permeable water repellent (VPWR) fabrics and synthetic battings that became available in recent years. Five VPWR fabrics evaluated were Hipora in three coating variants, $Gore-Tex^{\circledR}$ and $Aitace^{\circledR}$. Battings evaluated were $Viwarma^{\circledR}$, $Uniwarmr^{\circledR}$, $Thinsulate^{\circledR}$, and $Airseal^{\circledR}$ Thermal resistance and water vapor transmission were measured for each fabric and batting and in all combinations. Thermal resistance at zero and 37 cm/sec air velocity was determined by the Thermo Labo II technique for simultaneously measuring conduction and radiation heat transfer. Water vapor transmission over 24 hours was measured by a modified weight-gain method in a compact humid chamber at conditions simulating the clothing climate under heavy exercise ($40{\pm}1^{\circ}C$, $90{\pm}2\%$ R.H., and 0.5 m/sec air velocity). Fabric porosity was calculated from fiber density and fabric weight, thickness, and area. Thermal resistance results for the fabrics showed the effectiveness of coatings in inhibiting heat transfer. Measurements taken in wind were: $31.1\~37.6\%$ for $Hipora^{\circledR}$ variants; $31.0\%$ for $Gore-Tex^{\circledR}$; and $18.4\%$ for $Aitaca^{\circledR}$ Measurements without wind were higher but in the same order. Water vapor transmission results were in reverse order: $Aitac^{\circledR}$, $8.8 kg/m^{2};\;Gore-Tex^{\circledR}$, 6.4 kg/$m^{2}$; and $Hipora^{\circledR},\;4.4\~6.0\;kg/m^{2}$. In general thermal resistance increased with porosity. For battings, the thermal resistance with wind results were: $Viwarmu^{\circledR}$, $65.0\%;\; Thinsulate^{\circledR}$, $62.0\%$; $Uniwarm^{\circledR}$, $61.0\%$; and $Airseala^{\circledR},\;53.1\%$. Thermal resistance was proportional to thickness. Thermal resistance of fabric-batting combinations were $20\%$ higher than those of the battings only. Water vapor transmission for combinations was mainly affected by that for the VPWR fabric used.

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목재수피 파티클의 흡음율과 음향투과손실 (Sound Absorption Rate and Sound Transmission Loss of Wood Bark Particle)

  • Kang, Chun-Won;Jang, Eun-Suk;Jang, Sang-Sik;Kang, Ho-Yang;Kang, Seog-Goo;Oh, Se-Chang
    • Journal of the Korean Wood Science and Technology
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    • 제47권4호
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    • pp.425-441
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    • 2019
  • 목재수피의 음향성능을 파악하고자 6가지 수종의 목재수피를 삭편으로 절삭하여 몇 가지 비중조건과 두께로 만든 후 흡음율과 음향투과손실을 전달함수법과 전달행렬법으로 각각 측정하였다. 그 결과, 편백나무수피가 두께 100 mm 일 때의 100-6400 Hz 평균흡음율은 0.90이며 두께 50 mm 일때의 100-6400 Hz 평균흡음율은 0.84이다. 특히 두께 100 mm 일 때의 경우, 1 KHz의 주파수영역에서의 흡음율은 약 100%에 근접하는 높은 흡음율을 나타내었다. 음향투과손실은 측정주파수범위에서 편백나무수피는 500 Hz에서 15.30 dB의 투과손실을 나타내었고 1000 Hz 수치는 15.73 dB이었다. 10 mm 두께의 합판을 수피파티클 배면에 추가한 후에는 투과손실이 20-30 dB 증가하였다. 목재수피는 친환경적이면서 기존의 석고보드보다 흡음율이 높고 음향투과손실이 크게 나타나서 음향성능이 우수한 건축재료로 고려될 수 있다고 생각된다.

Sound Absorption Rate and Sound Transmission Loss of CLT Wall Panels Composed of Larch Square Timber Core and Plywood Cross Band

  • Kang, Chun Won;Jang, Sang Sik;Kang, Ho Yang;Li, Chengyuan
    • Journal of the Korean Wood Science and Technology
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    • 제47권1호
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    • pp.33-39
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    • 2019
  • The square timbers of larch having cross section of $90mm{\times}90mm$ were glued laterally to be formed $1,200mm{\times}2,400mm$ panels which were used as cores for CLT wall panels. Then, structural plywood panels having size of $1,200mm{\times}2,400mm$ were used as cross band covering the small square timber cores to manufacture CLT wall panels. The sound absorption rate of CLT wall panels and polyester board attached CLT wall panels were investigated. The mean sound absorption coefficients of the former and the latter in the frequency range of 100-6400 Hz were 0.21 and 0.74, respectively. The noise reduction coefficients (NRC) of those were 0.21 and 0.40, respectively. Also, the mean sound transmission loss of CLT wood panel in the frequency range of 50-1600 Hz was 45.12 dB and that value at the frequency of 500 Hz was 42.49 dB. It was suggested that the polyester board attached CLT wall panels could be used as housing wall because of its high sound absorption rate and high sound transmission loss.

Modeling the Dynamics and Control of Transmission of Schistosoma japonicum and S. mekongi in Southeast Asia

  • Ishikawa, Hirofumi;Ohmae, Hiroshi
    • Parasites, Hosts and Diseases
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    • 제47권1호
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    • pp.1-5
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    • 2009
  • A mathematical model for transmission of schistosomes is useful to predict effects of various control measures on suppression of these parasites. This review focuses on epidemiological and environmental factors in Schistosoma japonicum and Schistosoma mekongi infections and recent advances in mathematical models of Schistosoma transmission.

중국 결혼이민 여성의 전통복식 문화적응태도 및 착용실태 (Culture Adaptive Attitudes and Donning Practices of Traditional Dress among Chinese Marriage Immigrant Women)

  • 김순영;추호정;손진아;남윤자
    • 복식
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    • 제64권5호
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    • pp.154-167
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    • 2014
  • This study explored culture adaptive attitudes and donning practices of traditional dress among Chinese marriage immigrant women. Quantitative research was conducted on Korea-Chinese multicultural families. Participants were 291 married women in Seoul and Gyeonggi Province. The data was analyzed using frequency analysis, factor analysis, t-test and correlation analysis. The findings are as follows: First, positive relationship was found between Hanbok acceptance attitudes and Qipao transmission attitudes. The level of Qipao transmission attitudes was higher than Hanbok acceptance attitudes especially in the part of knowledge. Han Chinese showed stronger Qipao transmission attitudes than Korean Chinese. Immigrants without Korean nationality had stronger Qipao transmission attitudes. Higher education group and higher income group showed higher level both on Hanbok acceptance attitudes and Qipao transmission attitudes. Second, more than 50% of Chinese marriage immigrant women wore Hanbok once or twice per a year. On the other hand, only 24% of them wore Qipao. This result shows that there exists a gap in the Qipao transmission attitudes and donning practices. 44% of women wore both Hanbok and Qipao in their own wedding ceremony, 32% wore only Hanbok, and 19% wore only Qipao. 64% of women had an experience of wearing Hanbok on special days such as traditional holidays or family affairs, whereas only 29% had worn Qipao.

참오동나무의 열처리가 기체투과성, 흡음율과 음향투과손실에 미치는 영향 (Effect of Heat Treatment on the Gas Permeability, Sound Absorption Coefficient, and Sound Transmission Loss of Paulownia tomentosa Wood)

  • KANG, Chun-Won;JANG, Eun-Suk;JANG, Sang-Sik;Cho, Jae-Ik;KIM, Nam-Hun
    • Journal of the Korean Wood Science and Technology
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    • 제47권5호
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    • pp.644-654
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    • 2019
  • 참오동나무의 섬유방향기체투과성(gas permeability), 횡단방향 흡음율(sound absorption coefficient)과 음향투과손실(sound transmission loss)을 평가하고 열처리의 영향을 파악하고자 참오동나무 원반을 100, 160, $200^{\circ}C$로 열처리하고 기체투과성, 흡음율, 음향투과손실을 각각 측정하여 무처리 원반의 결과와 비교하였다. 그 결과, 두께 20 mm 참오동나무 원반의 섬유방향 기체투과성(specific permeability)은 무처리, 100, 160, $200^{\circ}C$ 열처리의 경우 각각 0.254, 0.279, 0.314, 0.452로 열처리에 의해 기체투과성이 약간 증가하였다. 두께 20 mm 무처리 참오동나무 원반의 50-6400 Hz 평균흡음율은 0.101이었으며 온도 100, 160, $200^{\circ}C$로 열처리한 목재의 50-6400 Hz 평균흡음율은 0.109, 0.096 그리고 0.106이었다. NRC (noise reduction coefficient) 는 각각 0.060, 0.067, 0.062 그리고 0.071 이었다. 두께 20 mm 무처리 참오동나무 원반의 50-6400 Hz 주파수범위에서 음향투과손실은 평균 36.93 dB이었다. 열처리에 의해 참오동나무 원반의 기체투과성과 흡음율은 열처리에 의해 그리고 열처리 온도 증가에 의해 약간 증가하였으나 증가정도는 미미하였다.

자기분화의 세대간 전이가 대학생의 심리적 적응에 미치는 영향 (The Effects of Intergenerational Transmission of Self-Differentiation on Psychological Adjustment of College Student)

  • 하상희;정혜정
    • 대한가정학회지
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    • 제46권7호
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    • pp.95-108
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    • 2008
  • The major purpose of this study was to investigate the effect of intergenerational transmission of self-differentiation on psychological adjustment of college students. Specifically, the present study endeavored to test the causal model focusing on the effect of the father's and the mother's self-differentiation on college student's psychological adjustment through the student's self-differentiation. The data were collected from 254 male and 293 female college students and their parents by using self-administered questionnaire method. The casual model was tested through structural equation model by using AMOS 7.0 program. The results showed that mother's and father's self-differentiation had direct and indirect effect on student's psychological adjustment. The results showed that both mother's and father's self-differentiation had direct effect on son's self-differentiation level, which directly influenced his psychological adjustment. The test of structural equation model also revealed that daughter's self-differentiation level was positively influenced only by mother's self-differentiation, while father's self-differentiation did not influenced female student's self-differentiation. Both male and female student's psychological adjustment was directly influenced by his or her self-differentiation level.