129,175 research outputs found

    Understanding Consumer Behaviour to Reduce Environmental Impacts through Sustainable Product Design

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    The use phase of the lifecycle of electrical products has a significant environmental impact, mainly determined by the consumer’s behaviour. Many consumers do not make the link between their daily consumption behaviour in the household and environmental problems such as climate change. In the 21st century, the residential sector, together with transport and industry, is one of the largest man-made contributors in the UK to climate change. It is argued that technological innovations, current eco-efficient products and consumer education have been ineffective in creating the long term radical behavioural change needed to reduce the impact of product use. Products, as the interface between consumers and consumption activities, have the potential to influence the way in which consumption occurs. In the sustainable design field however, designer responsibility traditionally considers raw material selection and product disposal. There is limited work that addresses the environmental impacts relating directly to use behaviour of the product. This paper illustrates that user behaviour studies can be the preliminary step for designers to improve energy efficiency of products. A single product type, household cold appliance, was chosen as a case to explore the capacity of designer-conducted user study to identify unsustainable aspects of product use. Adopting a user-centred approach, two pilot studies were used to gain an insight into domestic fridge and freezer use in the UK. Qualitative ethnographical research methods were employed to investigate the daily practices and “real” needs of user as well as the connection between the knowledge, attitudes, intention and actual action. The design suggestions drawn from the user behaviour analysis provide examples of how energy impact level of the interaction with the product can be reduced through design. Keywords: User-Centred Research; Sustainable Product Design; Changing Consumer Behaviour; Design Research; Household Energy Consumption; Household Cold Appliance.</p

    Effects of the Detection Efficiency on Multiplicity Distributions

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    In this paper we investigate how a finite detection efficiency affects three popular multiplicity distributions, namely the Poisson, the Binomial and the Negative Binomial distributions. We found that a multiplicity-independent detection efficiency does not change the characteristic of a distribution, while a multiplicity-dependent detection efficiency does. We layout a procedure to study the deviation of moments and their derivative quantities from the baseline distribution due to a multiplicity-dependent detection efficiency.Comment: 4 page

    Shock evolution in non-radiative supernova remnants

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    We present a new analytical approach to derive approximate solutions describing the shock evolution in non-radiative supernova remnants (SNRs). We focus on the study of the forward shock and contact discontinuity while application to the reverse shock is only discussed briefly. The spherical shock evolution of a SNR in both the interstellar medium with a constant density profile and a circumstellar medium with a wind density profile is investigated. We compared our new analytical solution with numerical simulations and found that a few percent accuracy is achieved. For the evolution of the forward shock, we also compared our new solution to previous analytical models. In a uniform ambient medium, the accuracy of our analytical approximation is comparable to that in Truelove&McKee (1999). In a wind density profile medium, our solution performs better than that in Micelotta et al. (2016), especially when the ejecta envelope has a steep density profile. The new solution is significantly simplified compared to previous analytical models, as it only depends on the asymptotic behaviors of the remnant during its evolution.Comment: Add discussion for contact discontinuit

    Gamma-Ray Emission from Supernova Remnant Interaction with Molecular Clumps

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    Observations of the middle-aged supernova remnants IC 443, W28 and W51C indicate that the brightnesses at GeV and TeV energies are correlated with each other and with regions of molecular clump interaction, but not with the radio synchrotron brightness. We suggest that the radio emission is primarily associated with a radiative shell in the interclump medium of a molecular cloud, while the gamma-ray emission is primarily associated with the interaction of the radiative shell with molecular clumps. The shell interaction produces a high pressure region, so that the gamma-ray luminosity can be approximately reproduced even if shock acceleration of particles is not efficient, provided that energetic particles are trapped in the cooling region. In this model, the spectral shape \ga 2 GeV is determined by the spectrum of cosmic ray protons. Models in which diffusive shock acceleration determines the spectrum tend to underproduce TeV emission because of the limiting particle energy that is attained.Comment: 15 pages, ApJ Letters, accepte

    A co-operating solver approach to building simulation

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    This paper describes the co-operating solver approach to building simulation as encapsulated within the ESP-r system. Possible adaptations are then considered to accommodate new functional requirements

    Determination of energetics and kinetics from single-particle intermittency and ensemble-averaged fluorescence intensity decay of quantum dots

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    Quantification of energetics and kinetics for the band-edge exciton states of quantum dots and the long-lived dark state is important for better understanding of the underlying mechanism for single-particle intermittency and ensemble fluorescence intensity decay. Based on a multistate diffusion-reaction model by extending our previous studies, we analyze experimental data from ensemble measurements and fluorescence intermittency of single quantum dots and determine important molecular-based quantities such as Stokes shift, free energy gap, activation energy, reorganization energy, and other kinetic parameters

    Chain dynamics and power-law distance fluctuations of single-molecule systems

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    Chain-dynamics-induced distance fluctuations between any two points in a finite chain with or without cross links are investigated. This model leads to three regimes of temporal behavior for distance autocorrelation: (i) initial flat time dependence, (ii) t–alpha power law, and (iii) long-time exponential decay. For an ideal Rouse chain with frequency-independent friction, alpha=(1/2). The span of the characteristic power-law behavior of a long chain could be reduced significantly with the presence of cross links
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