20,364 research outputs found

    The Oyster River Culvert Analysis Project

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    Studies have already detected intensification of precipitation events consistent with climate change projections. Communities may have a window of opportunity to prepare, but information sufficiently quantified and localized to support adaptation programs is sparse: published literature is typically characterized by general resilience building or regional vulnerability studies. The Fourth Assessment Report of the IPCC observed that adaptation can no longer be postponed pending the effective elimination of uncertainty. Methods must be developed that manage residual uncertainty, providing community leaders with decision-support information sufficient for implementing infrastructure adaptation programs. This study developed a local-scale and actionable protocol for maintaining historical risk levels for communities facing significant impacts from climate change and population growth. For a coastal watershed, the study assessed the capacity of the present stormwater infrastructure capacity for conveying expected peak flow resulting from climate change and population growth. The project transferred coupled-climate model projections to the culvert system, in a form understandable to planners, resource managers and decision-makers; applied standard civil engineering methods to reverse-engineer culverts to determine existing and required capacities; modeled the potential for LID methods to manage peak flow in lieu of, or combination with, drainage system upsizing; and estimated replacement costs using local and national construction cost data. The mid-21st century, most likely 25-year, 24-hour precipitation is estimated to be 35% greater than the TP-40 precipitation for the SRES A1b trajectory, and 64% greater than the TP-40 value for the SRES A1fi trajectory. 5% of culverts are already undersized for the TP-40 event to which they should have been designed. Under the most likely A1b trajectory, an additional 12% of culverts likely will be undersized, while under the most likely A1fi scenario, an additional 19% likely will be undersized. These conditions place people and property at greater risk than that historically acceptable from the TP-4025-year design storm. This risk level may be maintained by a long-term upgrade program, utilizing existing strategies to manage uncertainty and costs. At the upper-95% confidence limit for the A1fi 25-year event, 65% of culverts are adequately sized, and building the remaining 35%, and planned, culverts to thrice the cross-sectional area specified from TP-40 should provide adequate capacity through this event. Realizable LID methods can mitigate significant impacts from climate change and population growth, however effectiveness is limited for the more pessimistic climate change projections. Results indicate that uncertainty in coupled-climate model projections is not an impediment to adaptation. This study makes a significant contribution toward the generation of reliable and specific estimates of impacts from climate change, in support of programs to adapt civil infrastructures. This study promotes a solution to today\u27s arguably most significant challenge in civil infrastructure adaptation: translating the extensive corpus of adaptation theory and regional-scale impacts analyses into localscale action

    Incorporating life cycle external cost in optimization of the electricity generation mix

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    The present work aims to examine the strategic decision of future electricity generation mix considering, together with all other factors, the effect of the external cost associated with the available power generation technology options, not only during their operation but also during their whole life cycle. The analysis has been performed by integrating the Life Cycle Assessment concept into a linear programming model for the yearly decisions on which option should be used to minimize the electricity generation cost. The model has been applied for the case of Greece for the years 2012-2050 and has led to several interesting results. Firstly, most of the new generating capacity should be renewable (mostly biomass and wind), while natural gas is usually the only conventional fuel technology chosen. If externalities are considered, wind energy increases its share and hydro-power replaces significant amounts of biomass-generated energy. Furthermore, a sensitivity analysis has been performed. One of the most important findings is that natural gas increases its contribution when externalities are increased. Summing-up, external cost has been found to be a significant percentage of the total electricity generation cost for some energy sources, therefore significantly changing the ranking order of cost-competitiveness for the energy sources examined

    Environmental life cycle driven decision making in product design

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    There is growing interest in the assessment of products from a life cycle perspective. Product life cycles are often dominated by extensive chemical supply chains that lead up to the materials contained in the products and the overwhelming contribution that the production of these chemicals make to the overall life cycle due to their energy intensity. Hence, chemical engineers are uniquely positioned to carry out significant components of this assessment because of their skills in chemical process design and analysis. Furthermore, the complexity and extent of life cycle concerns creates opportunities for new process systems tools to be developed to support product design and analysis. The specific thesis objectives are threefold. The first is to develop a systematic methodology to optimize material selections for a product based on life cycle inventory (LCI) characteristics. The second is to use this methodology combined with sustainability assessment standards to assess whether these standards are congruent with life cycle assessment. The third is to develop an approach to design product sustainability assessment standards that are clear and consistent with life cycle principles. The overall contributions will be in the applied domain of life cycle assessment and its integration into standards setting, and in contributions to optimization tools and methods. The three objectives will be illustrated in the domain of carpet systems. Previous research has generated a substantial database of gate-to-gate (GTG) life cycle inventories for various chemicals that make up carpet, extending from the inputs to the final carpet mill back to the natural resources such as oil, natural gas and mined calcium carbonate. Carpet recycling is a promising alternative approach for reducing life cycle impacts and is being practiced at a growing scale in the U.S. This thesis uses the specific individual LCI gate-to-gate blocks for virgin materials and for important carpet recycling and general polymer recycling processes. A database for the GTG LCI will be used to construct a virtual chemical tree that automatically that represents the potential cradle-to-gate (CTG) use of resources. The alternatives for each possible route for the product will be generated, and optimization approaches will be applied to optimize the performance of the carpet system according to life cycle objectives. Sustainability assessment standards are currently being developed for a range of building products, such as carpet, resilient flooring, commercial textile coverings and office furniture. This activity has been stimulated through the considerable success of the U.S. Green Building Council's (USGBC) LEED standard. The LEED Standard is points-based: the building design and construction earns points for having certain attributes or promoting certain activities. The points are totaled and then the building earns a rating based on the total being above a certain threshold. The second thesis objective is met through extending the LCI optimization methodology to represent point-based standards. A product can then be optimized to maximize the number of points it earns or to minimize its life cycle attributes. This approach can be used to evaluate the effectiveness of an emerging carpet sustainability standard, NSF-140, in integrating LCI into the standard. The last objective, standard design, is approached through designing the tables that award points in the standard to be consistent with life cycle information. Certain minimum principles of consistency are articulated and then the designs shown to be consistent with these principles in the case that the life cycle impact assessment method maps the life cycle inventory to impact through a linear weighting.Ph.D.Committee Chair: Realff, Matthew; Committee Member: Agrawal, Pradeep; Committee Member: Ammons, Jane; Committee Member: Cook, Fred; Committee Member: Muzzy, Joh

    On green routing and scheduling problem

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    The vehicle routing and scheduling problem has been studied with much interest within the last four decades. In this paper, some of the existing literature dealing with routing and scheduling problems with environmental issues is reviewed, and a description is provided of the problems that have been investigated and how they are treated using combinatorial optimization tools

    Design and Construction Technique for Low Embodied Energy Building: An Analytical Network Process Approach

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    Energy performance in the construction industry is one of the significant features to be assessed in order to achieve sustainability in the built environment. There is a limited amount of literature on the analytical network process (ANP) in achieving sustainability towards reducing embodied energy. The aim of this study was to achieve buildings with less embodied energy through design, construction techniques and automation using ANP in order to promote sustainable construction. Data collection was primarily done by way of a well-structured questionnaire and an expert opinion survey. The responses retrieved from the questionnaire were analyzed using descriptive statistics and ranked accordingly. An ANP model was developed using multi-criteria decision-making based on the expert survey and used to prioritize and assign an important weighting for the identified criteria. The findings showed that multi-criteria decision-making with ANP when effectively employed will help in achieving sustainable buildings with low embodied energy. Reducing the amount of cement through design and building information modeling is the most significant factor towards achieving buildings with less embodied energy

    Energy Retrofit in European Building Portfolios: A Review of Five Key Aspects

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    The research about energy efficiency in buildings has exponentially increased during the last few years. Nevertheless, both research and practice still cannot rely on complete methodologies tailored for building portfolios as a whole, because the attention has always been drawn to individual premises. Yet, energy efficiency analyses need to go beyond the single building perspective and incorporate strategic district approaches to optimize the retrofit investment. For this purpose, several aspects should be considered simultaneously, and new methodologies should also be promoted. Therefore, this paper aims to discuss energy retrofit campaigns in building portfolios, drawing an exhaustive and updated review about the challenge of jumping from the single-building perspective to a stock-based analysis. This research discusses the publications available on the topic from five key aspects that are all essential steps in achieving a complete and reliable study of energy efficiency at a portfolio level. They are energy modelling and assessment, energy retrofit design, decision-making criteria assessment, optimal allocation of (financial) resources and risk valuation. This review, therefore, advocates for joint consideration of the problem as a basis on which to structure further disciplinary developments. Research gaps are highlighted, and new directions for future research are suggested
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