Evaluating the environmental impacts of a nano-enhanced field emission display using life cycle assessment: a screening-level study.

Carbon nanotube (CNT) field emission displays (FEDs) are currently in the product development stage and are expected to be commercialized in the near future because they offer image quality and viewing angles comparable to a cathode ray tube (CRT) while using a thinner structure, similar to a liquid crystal display (LCD), and enable more efficient power consumption during use. To address concerns regarding the environmental performance of CNT-FEDs, a screening-level, cradle-to-grave life cycle assessment (LCA) was conducted based on a functional unit of 10,000 viewing hours, the viewing lifespan of a CNT-FED. Contribution analysis suggests the impacts for material acquisition and manufacturing are greater than the combined impacts for use and end-of-life. A scenario analysis of the CNT paste composition identifies the metal components used in the paste are key contributors to the impacts of the upstream stages due to the impacts associated with metal preparation. Further improvement of the manufacturing impacts is possible by considering the use of plant-based oils, such as rapeseed oil, as alternatives to organic solvents for dispersion of CNTs. Given the differences in viewing lifespan, the impacts of the CNT-FED were compared with a LCD and a CRT display to provide more insight on how to improve the CNT-FED to make it a viable product alternative. When compared with CRT technology, CNT-FEDs show better environmental performance, whereas a comparison with LCD technology indicates the environmental impacts are roughly the same. Based on the results, the enhanced viewing capabilities of CNT-FEDs will be a more viable display option if manufacturers can increase the product's expected viewing lifespan.

An examination of existing data for the industrial manufacture and use of nanocomponents and their role in the life cycle impact of nanoproducts.

This work examines the manufacture and use of nanocomponents and how they can affect the life cycle impact of resulting nanoproducts. Available data on the production of nanoproducts and nanocomponents are used to identify the major groups of nanocomponents studied in this paper: inorganic nanoparticles, carbon-based nanomaterials, and specialty/composite materials. A comparison of existing results for life cycle assessments of nanocomponents and nanoproducts is used to possibly identifytrends in nanomanufacturing based on material grouping with regard to nonrenewable energy use and greenhouse gas emissions. Continuing work is needed in this area to incorporate other factors such as toxicity and resource consumption in addition to energy use and global warming potential to fully understand the role of nanomanufacturing in the life cycle of nanoproducts.

Studying the effect on system preference by varying coproduct allocation in creating life-cycle inventory.

How one models the input and output data for a life-cycle assessment (LCA) can greatly affect the results. Although much attention has been paid to allocation methodology by researchers in the field, specific guidance is still lacking: Earlier research focused on the effects of applying various allocation schemes to industrial processes when creating life-cycle inventories. To determine the impact of different allocation approaches upon product choice, this study evaluated the gas- and water-phase emissions during the production, distribution, and use of three hypothetical fuel systems (data that represent conventional gasoline and gasoline with 8.7 and 85% ethanol were used as the basis for modeling). This paper presents an explanation of the allocation issue and the results from testing various allocation schemes (weight, volume, market value, energy, and demand-based) when viewed across the entire system. Impact indicators for global warming, ozone depletion, and human health noncancer (water impact) were lower for the ethanol-containing fuels, while impact indicators for acidification, ecotoxicity, eutrophication, human health criteria, and photochemical smog were lower for conventional gasoline (impacts for the water-related human health cancer category showed mixed results). The relative ranking of conventional gasoline in relation to the ethanol-containing fuels was consistent in all instances, suggesting that, in this case study, the choice of allocation methodology had no impact on indicating which fuel has lower environmental impacts.

Life cycle assessment in management, product and process design, and policy decision making: a conference report.

On 24 September 2003, life cycle assessment (LCA) practitioners and decision makers gathered at the InLCA/LCM Conference in Seattle, Washington, USA (see http://www.lcacenter.org/InLCA-LCM03/index.html) to discuss the role of LCA in management, product design, process development, and regulatory/policy development decisions and to compare life cycle-based methods and tools with traditional product evaluation methods and tools. This article is a summary of that meeting and was prepared by the organizers as an overview of the many different technical, regulatory policy, and decision-making policy perspectives presented to an international gathering of participants representing academia and the industrial and regulatory communities.