Mapping the content and fates of scarce metals in discarded cars

A great variety of current products make use of components or materials (e.g. electronics, steel and aluminium alloys) that utilise increasing amounts of ‘critical’ or scarce metals (SM). For example, design trends for cars point at increasing SM utilisation in order for regulatory, business and consumer requirements on environmental performance, safety, costs, comfort and infotainment to be met. Modern cars now hold SM in substantial amounts, i.e. the circa one billion cars in use worldwide today, constitute a significant near-term secondary SM resource. However, current end-of-life vehicle (ELV) recycling is mainly aimed at isolating hazardous contents, dismantling spare parts and recycling bulk metals. There is thus a clear risk that ELV SM are not functionally recycled and thus lost for further use. Assessments of the opportunities for increased functional recycling require estimates of SM content of discarded cars and individual waste flows in ELV recycling. However, information on both is limited. Data related to cars is sparse, and challenged by the large range and age span of discarded car brands and models. Measurements of SM in waste flows are few and cover a limited range of SM. Consequently, available data does not allow us to quantify with precision the SM contents of discarded cars reaching the ELV recycling system, or map individual metal flows within it. Instead, our approach relies on mapping 25 ELV SM to main types of applications within three newly produced car models using automotive industry data (International Material Data System, IMDS), and letting these models represent the ELV fleet so that the annual input magnitudes of SM to ELV management can be estimated. Subsequently, we employ material flow analysis of ELV waste streams as basis for identifying potential pathways of these main applications, and the extent to which contained metals may reach processes capable of functional recycling. The approach allows us to qualitatively distinguish subsets of systems flows holding groups of SM, and discuss the potential for functional recycling. Using Swedish ELV management as a case, we conclude that only platinum may be functionally recycled in its main application. Cobalt, gold, manganese, molybdenum, palladium, rhodium and silver may be functionally recycled depending on application and pathways taken. For remaining 17 metals, functional recycling is lacking. Consequently, there is considerable risk of losing SM with current ELV procedures. Given differences in the application of metals and identified pathways, strategies for improving recycling and resource security are considered. Moreover, our case illustrates the considerable challenge, posed by the complexity and range of car configurations and the sparsity of information on SM, to closer assess recycling strategies and advance secondary SM resource utilisation

Analysing future solid waste generation - Soft linking a model of waste management with a CGE-model for Sweden

Parallel to the efforts of the EU to achieve a significant and overall reduction of waste quantities within the EU, the Swedish parliament enacted an environmental quality objective stating that ‘the total quantity of waste must not increase …’ i.e. an eventual absolute decoupling of waste generation from GDP. The decoupling issue is ad-dressed, in the present paper, by assessing future waste quantities, for a number of economic scenarios of the Swedish economy to 2030 with alternative assumptions about key factors affecting waste generation and waste management costs. We use an integrated top-down/bottom-up approach by linking a CGE-model of the Swedish economy with a systems engineering model of the Swedish waste management system. In this way, we can in more detail consider the interaction between waste generation and waste management costs (waste disposal prices) when assessing future waste quantities. A relative decoupling of waste generation takes place in all scenarios, i.e. total waste quantities increase at a lower rate than GDP. Absolute decoupling, which re-quire total waste quantities to stabilize or to reduce, does not take place in any of the scenarios. This means that the present Swedish Environmental quality objective of stabilizing waste quantities is not met in any of the scenarios with total waste genera-tion levels of 110 per cent up to nearly 200 per cent of that in 2006. The overall impression from our analysis is that costs are high for reducing waste generation irrespective of the type of waste reduced. In other words, the waste treat-ment costs are low compared to the costs for reducing waste. This situation also means that the use of policy instruments, which induce substitution by increasing the price of waste disposal services, will have very small reducing effects on the generation of all types of waste unless the price increase brings about an introduction of waste preventing techniques and affect households in the direction of a less waste intensive behaviour. For example, the policy instruments used must affect the pattern of household consumption pattern more directly, as a differentiation of the value added tax, rather than to be directed towards the waste management sector. Economic policy instruments introduced in the waste management sector are more likely to affect the choice of waste management solutions than prevent waste generation. Linking a macroeconomic and a systems engineering model for waste manage-ment, gives us a tool useful also for capturing the macroeconomic effects, such as GDP growth and structural changes, when designing policy instruments intended to prevent waste generation or take waste management in a more sustainable direction.general equilibrium model; systems engineering; solid waste; waste management; waste generation; decoupling; EMEC; NatWaste; top-down/bottom-up; waste policy instruments

Mechanical thrombectomy in acute ischemic stroke—experience from 6 years of practice

INTRODUCTION: We present our results from the first 6 years with mechanical thrombectomy in the treatment of ischemic stroke. METHODS: Every patient treated with mechanical thrombectomy for acute ischemic stroke from September 2005 to December 2011 was consecutively included in this retrospective analysis. Baseline and outcome data were retrieved from computerized records at the hospital. National Institute of Health Stroke Scale (NIHSS) score and the modified Rankin Scale (mRS) score were used as outcome parameters. Favorable outcome was defined as a mRS score of 0–2, corresponding to independence in activities of daily living. We also evaluated revascularization and severe adverse events, with focus on symptomatic intracranial hemorrhage. RESULTS: Good functional outcome (mRS 0–2) was achieved in 50 % (120/240) of all patients. For patients with no neurological deficit prior to stroke onset (i.e., mRS = 0 before stroke), the proportion with good functional outcome was 54 %. Symptomatic hemorrhages occurred in 4.6 % of the cases (5.7 % in the anterior circulation). CONCLUSION: In summary, our results supports that mechanical thrombectomy is a safe and effective method to restore blood flow in selected patients suffering from an acute ischemic stroke

An attempt to estimate out-of-plane lung nodule elongation in tomosynthesis images

In chest tomosynthesis (TS) the most commonly used reconstruction methods are based on Filtered Back Projection (FBP) algorithms. Due to the limited angular range of x-ray projections, FBP reconstructed data is typically associated with a low spatial resolution in the out-of-plane dimension. Lung nodule measures that depend on depth information such as 3D shape and volume are therefore difficult to estimate. In this paper the relation between features from FBP reconstructed lung nodules and the true out-of-plane nodule elongation is investigated and a method for estimating the out-of-plane nodule elongation is proposed. In order to study these relations a number of steps that include simulation of spheroidal-shaped nodules, insertion into synthetic data volumes, construction of TS-projections and FBP-reconstruction were performed. In addition, the same procedure was used to simulate nodules and insert them into clinical chest TS projection data. The reconstructed nodule data was then investigated with respect to in-plane diameter, out-of-plane elongation, and attenuation coefficient. It was found that the voxel value in each nodule increased linearly with nodule elongation, for nodules with a constant attenuation coefficient. Similarly, the voxel value increased linearly with in-plane diameter. These observations indicate the possibility to predict the nodule elongation from the reconstructed voxel intensity values. Such a method would represent a quantitative approach to chest tomosynthesis that may be useful in future work on volume and growth rate estimation of lung nodules

Adoption of Systemic and Socio-Technical Perspectives in Waste Management, WEEE and ELV Research

A greater quantity and variety of materials are being produced worldwide to meet demand for consumer products, buildings and infrastructure. Additionally, highly diffused products such as cars and electronics have become materially complex and depend on numerous scarce metals. Consequently, managing the societal supply of a variety of materials and metals sustainably is becoming increasingly important. This includes the use of efficient and effective waste management. However, the current management of waste in general and of waste consumer products specifically, have been pointed out as requiring significant developments to become more advanced to cope with the increasing material complexity. It has also been pointed out that research taking systems perspectives is crucial to improve waste management. Additionally, researching change processes and the co-evolution of social and technical factors (i.e., socio-technical change), has furthered the understanding of how ‘green’ industries develop in other empirical fields. Consequently, both systemic and socio-technical perspectives are likely relevant to waste management research. We used the Scopus database to search for 31 research approaches associated with such perspectives in journal articles writing about waste management in general, waste electrical and electronic equipment (WEEE) or end-of-life vehicles (ELVs). We conclude that, although the majority of the examined research does not mention the considered approaches, some environmental system analysis approaches are frequently mentioned and show signs of growth in adoption. In contrast, socio-technical approaches are scarcely mentioned. Consequently, we argue that there are relevant scientific tools yet to be adopted in waste management, WEEE and ELV research