14 research outputs found

    ENVIRONMENTAL UTILITY OF WOOD SUBSTITUTION IN COMMERCIAL BUILDINGS USING LIFE-CYCLE ANALYSIS.

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    Wood is the predominant construction material in the US residential sector. In commercial and midrise construction, the use of wood is limited compared with reinforced concrete and steel. Wood, being a natural, renewable material that sequesters carbon, is a natural fit for newer construction with enhanced sustainability goals. The objective of this study is to evaluate and identify the environmental utility (avoided emissions) of using wood in place of steel and concrete in the commercial construction and renovation sectors in Oregon, United States. The study used comparative, cradle-to-grave, life-cycle analysis, with Athena Impact Estimator for Buildings. Six case studies that represent different building functionalities, material systems, and construction techniques were modeled via the user interface input option, and the results were evaluated for global warming potential (GWP) and impacts on energy sources, such as fossil fuel consumption, when structural materials are substituted using wood. Out of the six case studies, one building was completely redesigned as per current codes using wood as the major structural material. Bills of materials for both wood redesigns and the as-built designs were used as input in the software and subsequently analyzed. Results showed that the average reduction in GWP due to wood substitution was about 60% across the six case studies. These findings reinforce the perception of wood as a green building material having potential for commercial construction. 

    Volatile halocarbon emissions by three tropical brown seaweeds under different irradiances

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    The emission rates of eight volatile halogenated compounds by three tropical brown seaweed species collected from Cape Rachado, west coast Peninsular Malaysia, under different irradiances have been determined. A purge-and-trap sample preparation system with a gas chromatograph and mass-selective detector was used to measure a suite of halocarbons released by Sargassum binderi Sonder ex J. Agardh, Padina australis Hauck, and Turbinaria conoides (J. Agardh) Kützing. All species are widely distributed in Peninsular Malaysia, with S. binderi a dominant seaweed species at our survey site. Release of few halocarbons was found to be influenced by irradiance. Correlations were also observed between emission of certain halocarbons with photosynthetic activity, especially bromo-and iodinated compounds (0.6 < r <0.9; p < 0.01) suggesting that environmental factors such as light can affect the release of these volatile halogenated compounds by the seaweeds into the atmosphere. Compared with temperate and polar brown seaweeds, tropical species, such as T. conoides, may emit higher levels of bromoform, CHBr3, and other halocarbons. It is therefore important to investigate the contribution of tropical seaweeds towards the local atmospheric composition of halocarbons
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