4,529 research outputs found
The improvement of product sustainability by the development of 'whole life' design methodologies
Sustainability-related legislation has increased over the past 10 years, and this is now having a profound effect on industry which is required to reduce its impacts. Those designing and manufacturing electro-mechanical products must also consider the impacts of the goods they produce. Many of these impacts stem from decisions made early on in the design process, and consequently it is here that effort must be focused.
One of the most significant lifecycle stages of any product is end of life, as it dictates how much of the material and embedded energy are recovered for reuse. Remanufacturing was found to be the only end of life option for electro-mechanical products that returned a product to a like-new quality, without first destroying the form of the component and loosing the embodied energy. Although remanufacture can require a high level of reprocessing, the process can be simplified if products are designed to facilitate this. Current design models in this area, however, offer inadequate assistance to designers, leading to confusion and a lack of real life application.
Through the use of a case study, this study set out to explore whether the impacts of electro-mechanical products could be reduced, by considering products on a component level and designing them to operate over multiple lives, without increasing cost or reducing quality. This proved to be true in the case of a stairlift.
Through life cycle assessment it was demonstrated that the whole life environmental impacts of a stairlift, representing a sample electro-mechanical product, could be significantly reduced by remanufacturing components at end of life. High impact components were targeted for remanufacture using the LCA data in combination with cost, sending the remainder of the product for recycling. Overall, environmental savings of 13% were witnessed. Incorporating sustainability in this fashion not only avoided any increase in cost to the manufacturer, but achieved a 34% reduction in overall production costs.
It was concluded that if the product had been optimised with desirable characteristics for remanufacture and recycling when in design, then these savings would be even more significant. To guide designers with embedding desirable characteristics into products, the end of life optimisation (EOLO) model was developed. This provides a framework for selecting components early in the design process for either remanufacture or recycling. The model goes on to rate current performance and provided guidelines on how to improve the design going forward
Various local global principles for abelian groups
We discuss local global principles for abelian groups by examining the adjoint functor pair obtained by (left adjoint) sending an abelian group to the local diagram \Cal L(A)=\{\Bbb Z_{(p)}\otimes A\rightarrow \Bbb Q\otimes A\} and (right adjoint) applying the inverse limit functor to such diagrams; runs through all integer primes. We show that the natural map A\rightarrow \varprojlim \Cal L(A) is an isomorphism if has torsion at only finitely many primes. If is fixed we answer the genus problem of identifying all those groups for which the local diagrams \Cal L(A) and \Cal L(B) are isomorphic. A similar analysis is carried out for the arithmetic systems \Cal S(A)=\{\Bbb Q\otimes A\rightarrow\Bbb Q\otimes A^{\wedge}\leftarrow A^{\wedge}\} and the local systems . The delicate relationship between the various adjoint functor pairs described above is explained
The transcription factors Egr2 and Egr3 are essential for the control of inflammation and antigen-induced proliferation of B and T cells
This article is available open access under a Creative Commons license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Copyright @ 2012 Elsevier Inc.Lymphocytes provide optimal responses against pathogens with minimal inflammatory pathology. However, the intrinsic mechanisms regulating these responses are unknown. Here, we report that deletion of both transcription factors Egr2 and Egr3 in lymphocytes resulted in a lethal autoimmune syndrome with excessive serum proinflammatory cytokines but also impaired antigen receptor-induced proliferation of B and T cells. Egr2- and Egr3-defective B and T cells had hyperactive signal transducer and activator of transcription-1 (STAT1) and STAT3 while antigen receptor-induced activation of transcription factor AP-1 was severely impaired. We discovered that Egr2 and/or Egr3 directly induced expression of suppressor of cytokine signaling-1 (SOCS1) and SOCS3, inhibitors of STAT1 and STAT3, and also blocked the function of Batf, an AP-1 inhibitor, in B and T cells. Thus, Egr2 and Egr3 regulate B and T cell function in adaptive immune responses and homeostasis by promoting antigen receptor signaling and controlling inflammation.Arthritis Research U
Does lighting affect pedestrian flows? A pilot study in Lund, Market Harborough and Dublin
A study records pedestrian footfalls in Lund, Dublin and Market Harborough during the day and after dark, either side of the Autumn 2016 clock change, using the change of end of civil twilight time to measure the effect of different lighting levels at the same clock time on footfall rates. Examination of total footfalls on weekdays and at weekends found significant decreases in counts after the clock change, on 5/6 sites on weekdays and half the sites at weekends. Further analysis found that the percentage decrease in the counts in the test period (same time/day of the week, light one week, dark the next) was more than in the control period (same time/day of the week, light both weeks), in 79% of counting sessions. The findings demonstrate higher reduction in footfalls on weekdays in mixed use areas, such as the sites selected in Dublin, and on Sundays in non-central locations
Analysis work to refine fabric energy efficiency assumptions for use in developing the Sixth Carbon Budget
The Climate Change Committee (CCC) commissioned University College London to review and update the cost and savings assumptions related to energy efficiency measures in homes, including an increased focus on in-use performance. The updated assumptions incorporate in-use measured data from the National Energy Efficiency Data-framework (NEED) alongside the latest evidence published by Government on the costs of measures. Over 150 datasets, studies and published reports were considered in total. The resulting assumptions were used as an input to Element Energy’s analysis ‘Development of trajectories for residential heat decarbonisation to inform the Sixth Carbon Budget’, focusing on existing home
Determinants of CO Exposure in the English Housing Stock: Modelling Current and Future Risks
This report investigates the current distribution of low-level CO concentrations in the English housing stock, and prevalence of dwellings exceeding recommended background exposure levels, using advanced modelling techniques informed by empirical data from a number of disparate sources. By bringing these sources of data together in the models, it is possible to produce new insights into the variation in background CO exposure across dwelling types and geographical location. The model also considers the impact on indoor domestic CO concentrations of the application of energy efficiency measures on the same stock. Although the health effects of long-term low-level CO exposure are still uncertain, this report provides evidence for further discussion and research. There are a number of assumptions listed within the main report, that drive the results. These should be taken into consideration when interpreting outcomes
Modelling the Influence of Layout On Overheating Risk of London Flats
An analysis of overheating levels corresponding to
building morphology yielded the modelling uncertainty
due to the geometry and layout of two-bedroom flats in
London, England. A new method is introduced, which
collates information on various flat layouts in the current
London housing stock. To ensure an unbiased sample was
selected, dwellings were chosen randomly, yielding
twelve flats in and around inner London. Dynamic
thermal simulations were performed using EnergyPlus to
determine individual dwellings’ overheating risk. The
results described the influence of geometry and layout
configuration on overheating risk, which has rarely been
analysed in previous studies. Irregular façades led to
higher overheating levels in the set-back part of the
building. Default configurations were used to model basecase archetypes, with further simulations performed to
study the effects of orientation, ceiling heights and
window glazing fractions. Compared with these factors,
bigger differences between mean operative temperatures
of flats were due to layout, with 3.5 °C in bedrooms,
1.5 °C in living rooms and 2.2 °C in kitchens
Wave-driven flow over shallow reefs
Long-term (1 month) observations of waves and currents over a natural reef are presented which show a strong correlation between offshore rms incident wave height and cross-reef currents at subtidal frequencies. The energy spectrum of the cross-reef currents shows a significant peak at twice the semidiurnal tidal frequency, while the spectrum of sea surface elevation over the reef flat shows no corresponding
peak. Furthermore, experimental results reported by Gourlay (1993) show setup over the reef occurs in the absence of a beach, and the cross-reef transport decreases with an increase in the sea surface slope across the reef flat due to an increase in setup at the top of the reef face. Analytic solutions for flow forced by wave breaking over an idealized reef explain the above features of cross-reef flows in the absence of a beach. Through the surf zone on the reef face the cross-reef gradient in the radiation stress
due to wave breaking is partitioned between balancing an offshore pressure gradient associated with setup over the reef and forcing a mean flow across the reef. Over the reef flat, where the depth is constant, there is no forcing due to wave breaking and the flow is driven by a pressure gradient which results from the setup through the surf zone. The magnitude of the setup through the surf zone is such that the transport across the reef flat matches the transport through the surf zone which is forced by the gradient in the radiation stress. Solutions are presented for general reef geometry, defined by the reef width and slope of the seaward reef face, and incident wave forcing, defined by the depth at the breakpoint and the depth of water over the reef. As the depth over the reef goes to zero, the solutions converge to the plane beach solutions described by Longuet-Higgins and Stewart (1964), wave setup is maximized, and the cross-reef transport is zero. In other cases the relative magnitudes of the setup and the cross-reef transport depend on the geometry of the reef and the incident wave forcing
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