Sustainable energy futures: Methodological challenges in combining scenarios and participatory multi-criteria analysis

This paper analyses the combined use of scenario building and participatory multi-criteria analysis (PMCA) in the context of renewable energy from a methodological point of view. Scenarios have been applied increasingly in decision-making about long-term consequences by projecting different possible pathways into the future. Scenario analysis accounts for a higher degree of complexity inherent in systems than the study of individual projects or technologies. MCA is a widely used appraisal method, which assesses options on the basis of a multi-dimensional criteria framework and calculates rankings of options. In our study, five renewable energy scenarios for Austria for 2020 were appraised against 17 sustainability criteria. A similar process was undertaken on the local level, where four renewable energy scenarios were developed and evaluated against 15 criteria. On both levels, the scenario development consisted of two stages: first an exploratory stage with stakeholder engagement and second a modelling stage with forecasting-type scenarios. Thus, the scenarios consist of a narrative part (storyline) and a modeled quantitative part. The preferences of national and local energy stakeholders were included in the form of criteria weights derived from interviews and participatory group processes, respectively. Especially in the case of renewable energy promotion in Austria, the paper systematically analyses the potentials and limitations of the methodology (1) for capturing the complexity of decision-making about the long-term consequences of changes in socio-economic and biophysical systems and (2) for appraising energy futures. The paper concludes that assessing scenarios with PMCA is resource intense, but this methodology captures successfully the context of technology deployment and allows decision-making based on a robust and democratic process, which addresses uncertainties, acknowledges multiple legitimate perspectives and encourages social learning.     

Variational multirate integration of constrained dynamics

Mechanical systems with dynamics on varying time scales, in particular those including highly oscillatory motion, impose challenging questions for numerical integration schemes. Tiny step sizes are required to guarantee a stable integration of the fast frequencies. However, for the simulation of the slow dynamics, integration with a larger time step is accurate enough. Small time steps increase integration times unnecessarily, especially for costly function evaluations. For systems comprising fast and slow dynamics, multirate methods integrate the slow part of the system with a relatively large step size while the fast part is integrated with a small time step. Main challenges are the identification of fast and slow parts (e.g. by separating the energy or by distinguishing sets of variables), the synchronisation of their dynamics and in particular the treatment of mixed parts that often appear when fast and slow dynamics are coupled by constraints. In this contribution, a multirate integrator is derived in closed form via a discrete variational principle on a time grid consisting of macro and micro time nodes. Variational integrators (based on a discrete version of Hamilton's principle) lead to symplectic and momentum preserving integration schemes that also exhibit good energy behavior. The resulting multirate variational integrator has the same preservation properties. An example demonstrates the performance of the multirate integrator for constrained multibody dynamics. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Constructing fair sports league schedules with regard to strength groups

A single round robin tournament (SRRT) consists of n teams and a set of periods. Matches between the teams have to be scheduled such that each team plays against each other team exactly once and each team plays at most once per period. In order to establish fairness among teams, we consider a partition of the teams into strength groups. Then, the goal is to avoid matches where a team plays against extremely weak or extremely strong teams in consecutive periods. In this paper, we pick up two concepts ensuring different degrees of fairness and address several questions which remained open so far.     

A high‐temperature furnace for in situ synchrotron X‐ray spectroscopy under controlled atmospheric conditions

A high‐temperature furnace with an induction heater coil has been designed and constructed for in situ X‐ray spectroscopic experiments under controlled atmospheric conditions and temperatures up to 3275 K. The multi‐purpose chamber design allows working in backscattering and normal fluorescence mode for synchrotron X‐ray absorption and emission spectroscopy. The use of the furnace is demonstrated in a study of the in situ formation of Cr oxide between 1823 K and 2023 K at logPO₂ values between ?10.0 and ?11.3 using X‐ray absorption near‐edge spectroscopy. The set‐up is of particular interest for studying liquid metals, alloys and other electrically conductive materials under extreme conditions.     

Laser grown single crystals of silicon

Single crystal rods of silicon have been grown by laser-induced chemical vapor deposition (LCVD) using visible light. We believe these to be the first reported single crystals of any material grown by LCVD.     

Synthese eines homologen steroidischen 17β-Pyrrolinons Partialsynthetische Versuche in der Reihe der Herzgifte, 9. Mitteilung

Synthesis of a homologous steroidal 17β-pyrrolinone. We describe the synthesis of 4′-[(3β-Hydroxy-androst-5-en-17β-yl)methyl]-3′-pyrrolin-2′-one ( 15 ) starting from 3β-acetoxy-23-diazo-21,24-dinorchol-6-en-22-one ( 1 ).