• 제목/요약/키워드: Environmental Degradation

검색결과 2,027건 처리시간 0.023초

Thermo-oxidation behaviour of organic matrix composite materials at high temperatures

  • Cinquin, Jacques;Colin, Xavier;Fayolle, Bruno;Mille, Marion;Terekhina, Svetlana;Chocinski-Arnault, Laurence;Gigliotti, Marco;Grandidier, Jean-Claude;Lafarie-Frenot, Marie-Christine;Minervino, Matteo;Cluzel, Christophe;Daghia, Federica;Ladeveze, Pierre;Zhang, Fangzouh
    • Advances in aircraft and spacecraft science
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    • 제3권2호
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    • pp.171-195
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    • 2016
  • The present paper is a review of the main activities carried out within the context of the COMPTINN' program, a joint research project founded by a FUI program (Fonds $Unifi{\acute{e}}s$ $Interminist{\acute{e}}riels$) in which four research teams focused on the thermo-oxidation behaviour of HTS-TACTIX carbon-epoxy composite at 'high' temperatures ($120^{\circ}C-180^{\circ}C$). The scientific aim of the COMPTINN' program was to better identify, with a multi-scale approach, the link between the physico-chemical mechanisms involved in thermo-oxidation phenomena, and to provide theoretical and numerical tools for predicting the mechanical behaviour of aged composite materials including damage onset and development.

Assessment of Carbon Stock in Chronosequence Rehabilitated Tropical Forest Stands in Malaysia

  • Kueh, Roland Jui Heng;Majid, Nik Muhamad;Ahmed, Osumanu Haruna;Gandaseca, Seca
    • Journal of Forest and Environmental Science
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    • 제32권3호
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    • pp.302-310
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    • 2016
  • The loss and degradation in tropical forest region are some of the current global concern. Hence, these issues elevated the role of rehabilitated forests in providing ecological products and services. The information on the carbon stock is important in relation to global carbon and biomass use, but lacking from the tropical region. This paper reports the assessment of tree and soil carbon stock in a chronosequence rehabilitated tropical forest stands in Malaysia. The study site was at the UPM-Mitsubishi Forest Rehabilitation Project, UPMKB. $20{\times}20m$ plot was established each and assessed in 2009 at 1-, 10- and 19-year-old sites while an adjacent ${\pm}23-year-old$ natural regenerating secondary forest plot was established for comparison. The overall total carbon stock was in the order of 19-year-old>${\pm}23-year-old$>10-year-old>1-year-old. When forest carbon stock is low, the soil component plays an important role in the carbon storage. The forest carbon recovery is crucial to increase soil carbon stock. The variations in the carbon stock showed the different stages of the forest recovery. Species survived after 19-years of planting are potential species for carbon sequestration activities in rehabilitated forest. Human intervention in rehabilitating degraded forest areas through tree planting initiatives is crucial towards recovering the forest ecological role especially in forest carbon stock capacity.

Isolation and characterization of micro satellite loci in the Korean crayfish, Cambaroides similis and application to natural population analysis

  • Ahn, Dong-Ha;Park, Mi-Hyun;Jung, Jae-Ho;Oh, Mi-Jin;Kim, Sang-Hee;Jung, Jong-Woo;Min, Gi-Sik
    • Animal cells and systems
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    • 제15권1호
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    • pp.37-43
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    • 2011
  • The Korean freshwater crayfish, Cambaroides similis, has recently suffered from range reduction and habitat degradation caused by environmental changes and water pollution. For the conservation and restoration of this species, it is necessary to understand the current population structures of Korean C. similis using estimation of their genetic variation. In this study, eight micro satellite loci were developed and characterized from 49 individuals collected from four locations: one population from Mt. Bukhan (BH) and three populations from Mt. Gwanak (GA) in Seoul, Korea. As a result, the number of alleles per locus ranged from 2 to 12. The observed heterozygosities and expected heterozygosities ranged from 0.000 to 0.833 and from 0.125 to 0.943, respectively, and the former values were significantly lower than the latter ones expected under the Hardy-Weinberg equilibrium. No significant linkage disequilibrium was revealed between any of the locus pairs after Bonferroni correction. From the pairwise Fst results over all samples, higher differentiation between GA-BH population pairs (mean 0.1789) was observed than between GA population pairs (mean 0.0454). This was also supported by Mantel's test showing that the genetic distances of these crayfish populations were significantly correlated with geographic distances. This result may show the regional differentiation caused by restricted gene flow between northern (BH) and southern (GA) populations within Seoul. These micro satellite markers have the potential for use in analyses of the genetic diversity and population structure of C. similis species, with implications for its conservation and management plans.

투수성 포장에 의한 비점오염원 저감 효과 분석 (Analysis of Non-point Pollution Source Reduction by Permeable Pavement)

  • 구영민;김영도;박재현
    • 한국수자원학회논문집
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    • 제47권1호
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    • pp.49-62
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    • 2014
  • 최근에 불투수층의 증가로 인하여 표면의 저류량이 감소하고 첨두유출과 전체 유출량은 증가한다. 첨두유출과 첨두유출 도달시간이 빨라지게 되면 홍수 발생률이 증가하여 도시유역의 피해를 증가시키며, 토양으로 침투되는 우수량이 감소하여 지하수위가 하강하게 되고 도시하천이 마르는 건천화가 진행되어 유역의 물 순환이 악화된다. 또한 하천 수질 오염의 원인은 점오염원과 비점오염원 등이 있는데, 비점오염원에 의한 오염이 점점 커져가는 양상이다. 이러한 이유는 도시유역이 지속적인 개발로 인해 불투수율이 증가하게 되어 초기강우에 오염물질이 하천으로 유입되고 있기 때문이다. 따라서 본 연구에서는 도시유역의 물순환 회복을 위한 투수성 포장 효과를 분석하며, 투수성 포장의 비점저감 효과 및 첨두유량 감소 효과를 분석하고자 한다. 도시유역 유출 모델인 SWMM을 이용하여 단기 유출 모의를 통하여 투수성 포장의 효과 분석하였다.

미생물 생촉매를 이용한 Trichloroethylene 연속처리용 생물반응기 시스템 평가 (Evaluation of Biocatalyst and Bioreactor System for the Continuous Treatment of Trichloroethylene)

  • 이은열
    • 생명과학회지
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    • 제13권6호
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    • pp.970-975
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    • 2003
  • 생촉매 및 생물막 반응기를 이용한 TCE 생분해는 TCE를 무해한 최종산물로 처리할 수 있는 환경친화적 방법이며, 초기 시설비와 운영비도 낮아 경제성도 우수한 기술로 평가할 수 있다. 그러나, TCE 및 독성 분해산물로 인하여 생촉매 불활성화가 일어나서 장기간 안정된 반응기 운전이 어렵고, TCE와 성장기질사이의 경쟁적 저해로 인하여 처리효율이 저하된다는 단점이 있다. 이러한 문제점을 극복하기 위하여 TCE 처리 단계와 생촉매 재활성화 단계를 구분시킨 2단계 CSTR/TBF 시스템에 대하여 TCE 연속처리용 시스템으로써의 실규모 적용 가능성을 평가해 보았다. B. cepacia 및 M. trichosporium을 생촉매로 사용한 2단계 CSTR/TBF 시스템은 고농도 유입 TCE와 다양한 운전조건에서도 28∼525mg TCE/1$.$day수준의 높은 TCE 처리효율을 안정되게 유지할 수 있어 산업폐가스 처리를 위한 실규모 처리 시스템으로 적용 가능성이 높다고 평가할 수 있었다.

역삼투 분리막의 표면개질을 이용한 내염소성 향상에 관한 연구 (A Study on Chlorine Resistance Improvement of Reverse Osmosis Membrane by Surface Modification)

  • 김영길;김노원;이용택
    • 멤브레인
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    • 제15권4호
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    • pp.320-329
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    • 2005
  • 본 연구에서는 polyamide계 방향족 역삼투막이 염소 라디칼에 의해 polyamide 결합이 분해되어 염배제율이 급격히 감소되는 반면 수투과도는 증가되는 것을 확인하였다 이러한 polyamide 역삼투막의 염소에 대한 저항성을 향상시키기 위해서 불소기 함유 실란커플링제(fluorine-containing silane coupling agent, FSCA)를 이용하여 역삼투막 표면 개질 후 막에 대한 표면 특성 및 내염소성 변화를 관찰하였다. 그 결과 FSCA의 농도가 증가될수록 막 표면이 dense하게 도포되었으며, 원소분석을 통해 FSCA가 부착되어 있음을 확인하였다. 또한 개질한 막 표면 조도는 감소되고 표면의 소수성이 증가됨을 접촉각의 증가로 확인 할 수 있었다. 이 결과를 종합하여 볼 때, 역삼투막을 FSCA로 표면개질 함으로써 개질막의 염소에 대한 저항성을 향상시킬 수 있었다.

미생물을 이용한 환경오염원의 분해에 관한 연구 II (Studies on the Decomposition of Environmental Pollutants by Utilizing Microorganisms)

  • 이재구;김기철;김창한
    • 미생물학회지
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    • 제20권2호
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    • pp.53-66
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    • 1982
  • 1. When Chong Ju and Chung Ju soils possessing different physicochemical properties were treated with 500 ppm of TOK and incubated in flooded anaerobic condition for 2, 4, and 6 months, respectively, they produced 4-Chloro-4'-amino diphenyl ether, 2,4-Dichloro-4'-amino diphenyl ether(amin-TOK), N-[4'-(4-Chlorophenoxy)] phenyl acetamide, and N-[4'-(4-Chlorophenoxy)] phenyl formamide as the metabolities. This result indicates that TOK undergose the reduction of its $NO_2\;to\;NH_2$ group, dechlorination, acetylation, and formylation under this condition. The cleavage of ether linkage does not occur. In addition, TOK degrades more readily in Chung Ju soil which is characterized by pH 6.43 and higher contents of $Ca^{++}$ and C.E.C. than in Chong Ju soil which is lower in pH, $Ca^{++}$, and C.E.C. 2. In the aerobic incubation of TOK of 25ppm in Chung Ju soil suspension for 21 days, the ratio of the resulting metabolites, TOK : amino-TOK : 4-Chloro-4'-amino diphenyl ether was 100 : 130 : 76. Meanwhile, in the 42 day incubation, the ratio was 100 : 19 : 5, which indicates that TOK in aerobic condition dose not necessrily degrade as a function of the incubation period. 3. The citrate buffer extract of Chung Ju soil has the capability of degrading TOK, which was verified to be due to the action of the microorganisms involved. 4. Twelye strains of soil bacteria were isolated from the TOK-treated soils. In the incubation of TOK in pure cultures of the respective isolates, the strain T-1-1 isolated from Chong Ju soil had almost no degradability whereas the strain T-2-3 was the most potent. The degradation of TOK by the isolates constituted mostly the reduction of the nitro group to amino group. 5. In a test for the degradability of TOK by some selected microorganisms, Pseudomonas species were more potent than fungi. Yet, Isolate B which had been isolated from Chung Ju soil suspension was the most potent.

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독일 루르지역의 지역재생정책: 추진과정과 성과에 대한 경로이론적 접근 (Regional Revitalization Policies of the Ruhr, Germany: Path Dependence or Path Creation?)

  • 신동호
    • 한국경제지리학회지
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    • 제17권1호
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    • pp.200-213
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    • 2014
  • 독일 루르지역은 1850년대부터 현지에서 채굴되는 석탄과 주변지역에서 생산되는 철광석을 기반으로 제철공업이 크게 발전하였다. 그러나 1950년대부터 루르지역의 제철공업이 경쟁력을 잃게 되었고, 석탄광업과 제철공업이 사양화되면서 조업중단과 공장폐쇄가 이어졌다. 루르지역의 탈공업화현상은 1970년대 및 1980년대에 최고조에 달했고, 1990년대 이후에는 공장폐쇄로 도시경제가 피폐해지고 사회간접자본의 노후화와 방치된 공장지구 등으로 도시경관과 환경오염이 심각하였다. 루르지역의 대표적인 도시 중 하나인 도르트문트시는 2000년부터 도르트문트 프로젝트라고 하는 도시재생사업으로 도시경제를 재건하고, 도시경관을 개선하여 도시경제구조를 쇄신하는 성공적인 모델을 제시하고 있다. 이 논문은 경로이론(Path Theory)에 입각하여 도르트문트의 도시재생사업을 조사, 연구하여 이론적, 정책적 시사점을 도출하고자 한다.

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System identification of soil behavior from vertical seismic arrays

  • Glaser, Steven D.;Ni, Sheng-Huoo;Ko, Chi-Chih
    • Smart Structures and Systems
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    • 제4권6호
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    • pp.727-740
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    • 2008
  • A down hole vertical seismic array is a sequence of instruments installed at various depths in the earth to record the ground motion at multiple points during an earthquake. Numerous studies demonstrate the unique utility of vertical seismic arrays for studying in situ site response and soil behavior. Examples are given of analyses made at two sites to show the value of data from vertical seismic arrays. The sites examined are the Lotung, Taiwan SMART1 array and a new site installed at Jingliao, Taiwan. Details of the installation of the Jingliao array are given. ARX models are theoretically the correct process models for vertical wave propagation in the layered earth, and are used to linearly map deeper sensor input signals to shallower sensor output signals. An example of Event 16 at the Lotung array is given. This same data, when examined in detail with a Bayesian inference model, can also be explained by nonlinear filters yielding commonly accepted soil degradation curves. Results from applying an ARMAX model to data from the Jingliao vertical seismic array are presented. Estimates of inter-transducer soil increment resonant frequency, shear modulus, and damping ratio are presented. The shear modulus varied from 50 to 150 MPa, and damping ratio between 8% and 15%. A new hardware monitoring system - TerraScope - is an affordable 4-D down-hole seismic monitoring system based on independent, microprocessor-controlled sensor Pods. The Pods are nominally 50 mm in diameter, and about 120 mm long. An internal 16-bit micro-controller oversees all aspects of instrumentation, eight programmable gain amplifiers, and local signal storage.

요 스트립검사 자동화를 위한 동시 비교 스캔 기법 예비 연구 (Automation of urine dipstick test by simultaneous scanning : A pilot study)

  • 이상봉;최성수;이인광;한정수;김완석;김원재;차은종;김경아
    • 센서학회지
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    • 제19권3호
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    • pp.169-175
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    • 2010
  • Urinalysis is an important clinical test to diagnose urinary diseases, and dipstick method with visual inspection is widely applied in practice. Automated optical devices recently developed have disadvantages of long measurement time, big size and heavy weight, accuracy degradation with time, etc. The present study proposed a new computer scanning technique, in which the test strip and the standard chart were simultaneously scanned to remove any environmental artifacts, followed by automated differentiation with the minimum distance algorithm, leading to significant enhancement of accuracy. Experiments demonstrated an accuracy of 100 % in that all test results were identical with the human visual inspection. The present technique only uses a personal computer with scanner and shortens the test time to a great degree. The results are also stored and accumulated for later use which can be transmitted to remote locations through a network, thus could be easily integrated to any ubiquitous health care systems.