131 resultados para Duty to mitigate the loss
Resumo:
Consumer goods contribute to anthropogenic climate change across their product life cycles through carbon emissions arising from raw materials extraction, processing, logistics, retail and storage, through to consumer use and disposal. How can consumer goods manufacturers make stepwise reductions in their product life cycle carbon emissions by engaging with, and influencing their main stakeholders? A semi-structured interview approach was used: to identify strategies and actions, stakeholders in the consumer goods industry (suppliers, manufacturers, retailers and NGOs) were interviewed about carbon emissions reduction projects. Based on this, a summarising presentation was made, which was shared during a second round of interviews to validate and refine the results. The results demonstrate several opportunities that have not yet been exploited by companies. These include editing product choice in stores to remove products with higher carbon footprints, using marketing competences for environmental benefits, and bundling competences to create winewinewin business models. Governments and NGOs have important enabling roles to accelerate industry change. Although this work was initially developed to explore how companies can reduce life cycle carbon emissions of their products, these strategies and actions also give insights on how companies can influence and anticipate stakeholder actions in general. © 2012 Elsevier Ltd. All rights reserved.
Resumo:
The origin of the transient crosstalk (TC) in a phase-only LCOS based WSS using a Fourier transform setup was investigated and identified. Two methods were proposed to reduce the TC by at least 5dB without the need to modify the optics or electronics in use. © 2013 OSA.
Resumo:
The power-conversion efficiency of solid-state dye-sensitized solar cells can be optimized by reducing the energy offset between the highest occupied molecular orbital (HOMO) levels of dye and hole-transporting material (HTM) to minimize the loss-in-potential. Here, we report a study of three novel HTMs with HOMO levels slightly above and below the one of the commonly used HTM 2,2′,7,7′- tetrakis(N,N-di-p-methoxyphenylamino)-9,9′- spirobifluorene (spiro-OMeTAD) to systematically explore this possibility. Using transient absorption spectroscopy and employing the ruthenium based dye Z907 as sensitizer, it is shown that, despite one new HTM showing a 100% hole-transfer yield, all devices based on the new HTMs performed worse than those incorporating spiro-OMeTAD. We further demonstrate that the design of the HTM has an additional impact on the electronic density of states present at the TiO2 electrode surface and hence influences not only hole- but also electron-transfer from the sensitizer. These results provide insight into the complex influence of the HTM on charge transfer and provide guidance for the molecular design of new materials. © 2013 American Chemical Society.
Resumo:
Resonant-based vibration harvesters have conventionally relied upon accessing the fundamental mode of directly excited resonance to maximize the conversion efficiency of mechanical-to-electrical power transduction. This paper explores the use of parametric resonance, which unlike the former, the resonant-induced amplitude growth, is not limited by linear damping and wherein can potentially offer higher and broader nonlinear peaks. A numerical model has been constructed to demonstrate the potential improvements over the convention. Despite the promising potential, a damping-dependent initiation threshold amplitude has to be attained prior to accessing this alternative resonant phenomenon. Design approaches have been explored to passively reduce this initiation threshold. Furthermore, three representative MEMS designs were fabricated with both 25 and 10 μm thick device silicon. The devices include electrostatic cantilever-based harvesters, with and without the additional design modification to overcome initiation threshold amplitude. The optimum performance was recorded for the 25 μm thick threshold-aided MEMS prototype with device volume ∼0.147 mm3. When driven at 4.2 ms -2, this prototype demonstrated a peak power output of 10.7 nW at the fundamental mode of resonance and 156 nW at the principal parametric resonance, as well as a 23-fold decrease in initiation threshold over the purely parametric prototype. An approximate doubling of the half-power bandwidth was also observed for the parametrically excited scenario. © 2013 IOP Publishing Ltd.
Resumo:
The origin of the transient crosstalk (TC) in a phase-only LCOS based WSS using a Fourier transform setup was investigated and identified. Two methods were proposed to reduce the TC by at least 5dB without the need to modify the optics or electronics in use. © 2013 OSA.
Resumo:
In the domain of energy storage, electrochemical capacitors have numerous applications ranging from hybrid vehicles to consumer electronics, with very high power density at the cost of relatively low energy storage. Here, we report an approach that uses vertically aligned carbon nanotube arrays as electrodes in electrochemical capacitors. Different electrolytes were used and multiple parameters of carbon nanotube array were compared: carbon nanotube arrays were shown to be two to three times better than graphite in term of specific capacitance, while the surface functionalization was demonstrated to be a critical factor in both aqueous and nonaqueous solutions to increase the specific capacitance. We found that a maximum energy density of 21 Wh/kg at a power density of 1.1 kW/kg for a hydrophilic electrode, could be easily achieved by using tetraethylammonium tetrafluoroborate in propylene carbonate. These are encouraging results in the path of energy-storage devices with both high energy density and power density, using only carbon-based materials for the electrodes with a very long lifetime, of tens of thousands of cycles. © 2011 IEEE.
Resumo:
In typical conventional foundation design, the inherent variability of soil properties, model uncertainty and construction variability are not modeled explicitly. A main drawback of this is that the effect of each variability on the probability of an unfavorable event cannot be evaluated quantitatively. In this paper, a method to evaluate the uncertainty-reduction effect on the performance of a vertically-loaded pile foundation by monitoring the pile performance (such as pile load testing or placing sensors in piles) is proposed. The effectiveness of the proposed method is examined based on the investigation of a 120-pile foundation placed on three different ground profiles. The computed results show the capability of evaluating the uncertainty-reduction effect on the performance of a pile foundation by monitoring. © 2014 Taylor & Francis Group, London.