Constructive uniqueness proofs of stationary vacuum Black Hole spacetimes including the case of degenerate horizons

Schwarze Löcher hoher Symmetrie sind mögliche Endprodukte eines Sternenkollapses und werden im Rahmen der Allgemeinen Relativitätstheorie (ART) beschrieben. Die Ernstgleichung ist die wesentliche Feldgleichung der ART im Falle einer stationären und axialsymmetrischen Vakuumraumzeit. Die Grundlage der vorliegenden Arbeit bildet das von Gernot Neugebauer entwickelte Lineare Problem für die Ernstgleichung; mit dessen Hilfe können die Einsteingleichungen für eine stationäre und axialsymmetrische Vakuumraumzeit als Randwertproblem formuliert und für einfache Randbedingungen analytisch gelöst werden. Ein konstruktiver Eindeutigkeitsbeweis für das nicht entartete, stationär rotierende Schwarze Loch (Kerr-Metrik) konnte auf diese Weise von den beiden Autoren Reinhard Meinel und Gernot Neugebauer gegeben werden. Ziel dieser Arbeit ist es, den vorhandenen Eindeutigkeitsbeweis so abzuändern, daß er auf einen entarteten Horizont angewendet werden kann, was zur extremen Kerrlösung führt. Um dieses Resultat in die Reihe der existierenden Existenz- und Eindeutigkeitsbeweise für stationäre und asymptotisch flache Vakuumlösungen mit Schwarzen Löchern einzordnen, sind weitere Schritte nötig, welche diskutiert und zum Teil bewiesen werden

Balance issues in input–output analysis: A comment on physical inhomogeneity, aggregation bias, and coproduction

Recently, Merciai and Heijungs (2014) demonstrated that monetary input–output (IO) analysis can lead to system descriptions that do not conserve mass when the assumption of homogeneous prices is violated. They warn that this violation of basic balance laws can lead to biased estimates of environmental impacts, and they therefore recommend performing IO analysis in a physically accounted framework. We take a broader scope on this issue and present price inhomogeneity as a special case of product mix inhomogeneity. We demonstrate that even a fully physically accounted IO analysis or lifecycle assessment will violate balance laws if it suffers from inhomogeneous aggregation. The core issue is not whether a system is described using monetary or physical units, but rather whether product groups are too aggregated to allow for the concurrent respect of energy, mass, financial and elemental balances. We further analyze the link between the violation of physical balances and the introduction of biases. We find that imbalances are neither a necessary nor a sufficient condition for the presence of systematic errors in environmental pressure estimates. We suggest two ways to leverage the additional explanatory power of multi-unit inventory tables to reduce instances of imbalances and aggregation biases

Material efficiency strategies to reducing greenhouse gas emissions associated with buildings, vehicles, and electronics - A review

As one quarter of global energy use serves the production of materials, the more efficient use of these materials presents a significant opportunity for the mitigation of greenhouse gas (GHG) emissions. With the renewed interest of policy makers in the circular economy, material efficiency (ME) strategies such as light-weighting and downsizing of and lifetime extension for products, reuse and recycling of materials, and appropriate material choice are being promoted. Yet, the emissions savings from ME remain poorly understood, owing in part to the multitude of material uses and diversity of circumstances and in part to a lack of analytical effort. We have reviewed emissions reductions from ME strategies applied to buildings, cars, and electronics. We find that there can be a systematic trade-off between material use in the production of buildings, vehicles, and appliances and energy use in their operation, requiring a careful life cycle assessment of ME strategies. We find that the largest potential emission reductions quantified in the literature result from more intensive use of and lifetime extension for buildings and the light-weighting and reduced size of vehicles. Replacing metals and concrete with timber in construction can result in significant GHG benefits, but trade-offs and limitations to the potential supply of timber need to be recognized. Repair and remanufacturing of products can also result in emission reductions, which have been quantified only on a case-by-case basis and are difficult to generalize. The recovery of steel, aluminum, and copper from building demolition waste and the end-of-life vehicles and appliances already results in the recycling of base metals, which achieves significant emission reductions. Higher collection rates, sorting efficiencies, and the alloy-specific sorting of metals to preserve the function of alloying elements while avoiding the contamination of base metals are important steps to further reduce emissions

Circular economy inspired imaginaries for sustainable innovations

In this chapter, Narayan and Tidström draw on the concept of imaginaries to show how Circular Economy (CE) can facilitate values that enable sustainable innovation. Innovation is key for sustainability, however, understanding and implementing sustainable innovation is challenging, and identifying the kind of actions that could direct sustainable innovations is important. The findings of this study indicate that CE-inspired imaginaries enable collaboration and by relating such imaginaries to common and shared social and cultural values, intermediaries could motivate actors into taking actions that contribute to sustainable innovation.fi=vertaisarvioitu|en=peerReviewed

Quantifying longevity and circularity of copper for different resource efficiency policies at the material and product levels

Resource efficiency strategies are emerging on policy agendas worldwide. Commonly, resource efficiency policies aim at decreasing losses at the waste management stage and, thus, diverge from public interest in more comprehensive resource efficiency measures that include a focus the earlier material life cycle stages. Just in recent years, improvements in the lifetimes of products and increased repair and reuse ability have become policy objectives in some countries. However, the effectiveness of policy measures is usually not assessed, even though it is crucial to support informed policy‐making and efficiently decrease the environmental impact of resource use. In this paper, we provide such an assessment for the copper cycle, the third most consumed metal with sharply increasing demand. Under current practices, in Western Europe and North America, 50% and 44% of the losses by 2050 occur at end‐of‐life collection, and only 2% of losses take place at the recovery stage; in Middle East and Africa for 19% and 54%, respectively. By 2050, most copper would be lost in China with a proportion of 58%. We evaluate the resource efficiency by quantifying the two key parameters, circularity and longevity, that is, how often and how long the material is in use in the anthroposphere. Our results show that the current global longevity of high‐grade copper is 47 ± 2.5 years, and a copper atom is used in 2.1 ± 0.1 applications on average. Ambitious political measures across the life cycle can increase longevity by 85% and circularity by 45%.Ministry of Science, Research and the Arts of Baden Württemberg (Germany

Metal content of commodities

This is a dataset of the approximate contentation of the materials steel, plastics, paper, and cement and of the metals Fe, Cu, Al, Cr, Mn, Mo, and V of ca. 4000 Commodity groups in the Eurostat ProdCom database. (NACE v2)<br>The dataset was developed for the following work:<br>"Quantifying Impacts of Consumption Based Charge for Carbon Intensive Materials on Products " Stefan Pauliuk, Karsten Neuhoff, Anne Owen, Richard Wood DIW Discussion paper 1570, German Institute for Economic Research, Berlin

Integrating Life Cycle Assessment into the Framework of Environmental Impact Assessment for Urban Systems: Framework and Case Study of Masdar City, Abu Dhabi

Planning urban expansion under the interconnected Sustainable Development Goals requires a systemic analysis of its environmental impacts. The benefits of integrating the widely used system analysis tool life cycle assessment (LCA) into the planning process tool environmental impact assessment (EIA) are described in the literature. However, not many applications of such an integration have been conducted. The aim of this study is to refine the framework for integrating LCA into the process of EIA and to apply this framework to an example of urban expansion: Masdar City in Abu Dhabi. The integrated framework builds on the complementarity between the scope and assessment steps of the tools and assesses the impacts for the areas of protection: human health, ecosystem, and resources. The framework is then applied to the vehicles, buildings, and infrastructure in the city’s first development phase (DP1). Major environmental stressors include the loss of existing desert ecosystem and the utilization of non-renewable sources of energy at various development stages of DP1. Substituting natural gas-based electricity with solar power could potentially save 46% of current carbon emissions. To mitigate the land transformation impacts, construction of “close-to-nature” artificial habitats, and increased use of low-carbon fuels is suggested

Modelling Hazard for Tailings Dam Failures at Copper Mines in Global Supply Chains

The global mining industry generates several billion tons of waste every year. Much of it is stored in liquid form, known as tailings, in large impoundments. Recent dam failures at tailing ponds with catastrophic outcomes have raised public concern, such that industry initiatives and investors are beginning to address the problem. So far, a lack of publicly available data makes an independent and comprehensive risk assessment challenging. We introduce a simple and transparent hazard indicator built from environmental proxy variables and screen a global sample of 112 copper mines for natural hazards regarding tailings dams. In a second step, material footprints of copper for the European Union and five major economies are estimated and compared using a Multi-Regional Input–Output model, shedding light on the regions of origin. Finally, hazard scores are linked to regional copper footprints to identify hotspots in supply chains of final consumption. The most hazardous mines are located in Chile and Peru including some of the world’s largest copper producers. China and the US have the largest copper ore footprints and per capita values in the US were 25 times larger than in India. The United States’ and European footprints are satisfied by domestic extraction to about 66 and 40 percent respectively. Copper from Poland contributes around 19 and 28 percent to supply chains of German and European final demand respectively and, as a consequence, Poland constitutes the main hazard hotspot for Europe’s copper supply chain