• Title/Summary/Keyword: natural materials

Search Result 4,511, Processing Time 0.038 seconds

Effect of Fiber Orientation on Failure Strength Properties of Natural Fiber Reinforced Composites including Adhesive Bonded Joint (접착제 접합된 자연섬유강화 복합재료의 파괴강도 특성에 미치는 섬유 방향의 영향)

  • Yoon, Ho-Chel
    • Journal of Welding and Joining
    • /
    • v.24 no.5
    • /
    • pp.43-48
    • /
    • 2006
  • This paper is concerned with a fracture strength study of composite adhesive lap joints. The tests were carried out on specimen joints manufactured hybrid stacked composites such as the polyester and bamboo natural fiber layer. The main objective of the work was to test the fracture strength using hybrid stacked composites with a polyester and bamboo natural fiber layer. Tensile and peel strength of hybrid stacked composites are tested before appling adhesive bonding. From results, Natural fiber reinforced composites have lower tensile strength than the original polyester. and The load directional orientation and small amount and low thickness of bamboo natural fiber layer have a good effect on the tensile and peel strength of natural fiber reinforced composites. The failure strength of these materials applied adhesive bonding is also affected by fiber orientation and thickness of bamboo natural fiber layer. There for, Fiber orientation of bamboo natural fiber layer have a great effect on the tensile-shear strength of natural fiber reinforced composites including adhesive bonded joints.

Screening for Antagonistic Natural Materials Against Alternaria alternata (Alternaria alternata에 항균력이 있는 천연물 조사)

  • 김영호;오연현;오승환
    • Korean Journal Plant Pathology
    • /
    • v.12 no.1
    • /
    • pp.66-71
    • /
    • 1996
  • 79종의 식물재료의 Alternaria alternata에 대한 항균활성을 조사한 결과, 7가지 식물재료가 항균활성이 있었고, 11가지는 확실치 않았으며, 나머지 61가지는 항균활성이 나타나지 않았다. A. alternata에 항균활성이 나타난 7가지 식물재료 중 계피가 활성이 가장 높았으며, 오미지와 천궁이 중정도의 활성을 보였으며, 나머지는 약한 활성을 나타내었다. 항균 활성 성분은 계피와 천궁의 경우는 diethyl ether에 분리되었고, 오미자의 경우는 butanol에 분리되었다. 계피의 diethyl ether 추출물은 1,000 배액 이하에서 식별 가능한 항균활성이 나타났다. 계피의 성분으로 cinnam aldehyde가 가장 높은 활성을 보여, 이 물질이 계피의 주요 항균물질로 사료된다.

  • PDF

Effect of Low Calorific Natural Gas on Performance and Emission Characteristics of Engine (저발열량 천연가스가 엔진 성능 및 배기특성에 미치는 영향)

  • Lee, Sungwon;Lim, Gihun;Park, Cheolwoong;Choi, Young;Kim, Changgi
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.37 no.12
    • /
    • pp.1129-1135
    • /
    • 2013
  • In this, three types of natural gas were employed to investigate the effect of low-calorific natural gas on the performance of and emissions from a heavy-duty CNG engine. The performance and emission characteristics were analyzed by conducting a full-load test, WHSC mode test, and WHTC mode test. The results showed that the torque of low-calorific natural gas with $9,800kcal/Nm^3$ of higher heating value decreased by 4.4 compared to that of the current natural gas with $10,400kcal/Nm^3$ of heating value. With low-calorific fuels, CO, $CO_2$, and $NO_x$ emissions decreased. However, THC emissions increased. According to the WHSC and WHTC mode test results, the thermal efficiency increased and the emission characteristics showed a similar trend to the full-load test results. Low-calorific natural gases cause a decrease in torque at full-load operation conditions and an increase in hydrocarbon emissions.

Free vibration of deep curved FG nano-beam based on modified couple stress theory

  • Rahmani, O.;Hosseini, S.A.H.;Ghoytasi, I.;Golmohammadi, H.
    • Steel and Composite Structures
    • /
    • v.26 no.5
    • /
    • pp.607-620
    • /
    • 2018
  • Vibration analysis of deep curved FG nano-beam has been carried out based on modified couple stress theory. Material properties of curved Timoshenko beam are assumed to be functionally graded in radial direction. Governing equations of motion and related boundary conditions have been obtained via Hamilton's principle. In a parametric study, influence of length scale parameter, aspect ratio, gradient index, opening angle, mode number and interactive influences of these parameters on natural frequency of the beam, have been investigated. It was found that, considering geometrical deepness term leads to an increase in sensitivity of natural frequency about variation of aforementioned parameters.

Development of Soil-cement in Earth-block Materials

  • Wiwattanachang, N;Maneein, N;Parwong, T;Nummeesri, K
    • International Journal of Advanced Culture Technology
    • /
    • v.3 no.1
    • /
    • pp.78-85
    • /
    • 2015
  • In Thailand, the electricity consumption is very high with the intention of reduce high temperature in the building. Since 2000, a lot of people paying attention to Green-Building concept. A similar concept is natural building, which is usually on a smaller scale and tends to focus on the use of natural materials that are available locally. Therefore, the Earth-Block (EAB) product is appropriated approach to reduce energy consumption in the buildings. The EAB is produced with environmentally friendly process, which does not release harmful pollution and effective cost. The main significant character is durable materials for building construction. This study aims to develop the new thermal insulation by using soil-cement with vetiver grass fibre. Additionally, it describes the innovative systems used in production of EAB materials by mixing the soil-cement with vetiver grass fibre. This paper reveals lowest costs, space configurations changing and greater design flexibility for constructing the building.