Structural vulnerability of energy distribution systems: Incorporating infrastructural dependencies

In this paper a novel method for assessing the structural vulnerability of two coupled energy distribution systems is presented. The co-existing of an electric power distribution system and a district heating system is described and modelled, under the assumption that the operation of the district heating system is directly dependent on electric power. The structural vulnerability of the two systems subject to single failures or a set of simultaneous failures in the power system is found. Thus, the consequences of power system failures for the energy supply as a whole are quantified.     

Hydro reservoir handling in Norway before and after deregulation

The Norwegian Energy Act that came into force in 1991 deregulated the electricity market and removed the former obligation power companies had to supply electricity to the geographical area they were responsible for. Hence producers can supply electricity on the basis of profitability. In 2007 the Energy Act was evaluated by the Government. As a part of this, a study concerning hydro reservoir handling before and after deregulation was carried out by SINTEF. Public statistics show that average hydro reservoir levels measured in per cent of reservoir capacity have been reduced after 1990. We have used the power-market model EMPS¹ (EFI's Multi-area Power-market Simulator) to analyze if this reduction can be explained by natural variation in climatic variables or by structural changes that have occurred after 1990. Simulation results show that the reduced reservoir levels cannot be explained by natural variation in climatic variables. Structural changes such as increased transmission capacities can, however, explain some of the reduction. Our study does not indicate that the present reservoir handling gives reservoir levels that are too low. In this paper we also describe the stochastic dynamic optimization problem for long-term hydropower scheduling, and we explain how this problem actually is solved by the EMPS model.     

On the Ring-Opening of Some 3-Lithiobithienyls and 3′-Lithio-α-terthienyls

3-Halobithienyls have been prepared through the Pd(PPh₃)₄-catalyzed coupling of thiopheneboronic acids with 2,4-dihalothiophenes. The ring-opening of the corresponding 3-lithiobithienyls obtained upon halogen-metal exchange with phenyllithium has been investigated. Compound 12 , 3′-iodo-2,2′,2″-terthienyl, was prepared in one step through the Pd(PPh₃)₄-catalyzed coupling of two equivalents of 2-thiopheneboronic acid with 2,3,5-triiodothiophene. Treatment of 12 with phenyllithium and methyl iodide gave a mixture of compounds 10 and 11 occurring in Berkheya and Cullumia species.     

<Superscript>31</Superscript>P NMR quantification and monophasic solvent purification of human and bovine lens phospholipids

Most lipid extraction procedures [Folch, J., Lees, M., and Sloane-Stanley, G.H., (1957) A Simple Method for the Isolation and Purification of Total Lipids from Animal Tissues, J. Biol. Chem. 226, 497–509; Bligh, E.G., and Dyer, W.J. (1959) A Rapid Method of Total Lipid Extraction and Purification, Can. J. Biochem. Physiol. 37, 911–917] employ biphasic solvent mixtures designed to dissolve the lipids in an organic phase and remove impurities in an aqueous phase. However, when applying these protocols to biological matrices such as that of the ocular lens, the formation of an emulsion layer between the organic and aqueous phases causes poor reproducibility in extraction yields and gives only a small amount of the lipid-containing chloroform phase. In this study, we quantified phospholipids at each step of the Folch et al. extraction protocol and compared the yield of human and bovine lens phospholipids obtained by the Folch-based approach and a novel monophasic methanol extraction method designed to circumvent the problems associated with biphasic extraction protocols. A monophasic methanol extraction coupled with ³¹P NMR spectroscopy was found to be the simplest, quickest, and most effective method for quantifying the phospholipid content of the lens.     

Active centers, catalytic behavior, symbiosis and redox properties of MoV(Nb,Ta)TeO ammoxidation catalysts

Selective as well as waste forming active centers were defined for MoVNbTeO and MoVTaTeO catalysts in the ammoxidation of propane to acrylonitrile and all catalytic functionalities were assigned to specific elements at the respective active centers. Symbiosis between M1 and M2 phases of these catalysts was observed, with phase cooperation being more extensive in the Nb than Ta containing compositions. The difference in catalytic effectiveness arises most likely because contact and surface area exposure of the two respective, cooperating phase pairs are not equal. The M1 phase of the catalysts is reducible by propane and ammonia in the absence of dioxygen and is regenerable to its original, fully oxidized state by dioxygen (air). No structural collapse is observed even after 120 C₃H₈ + NH₃ reduction pulses. The so induced reduction of the catalyst extends up to 70 layers deep. The product distribution over the first few pulses is very similar to that under catalytic conditions, supporting the concept that lattice oxygen is involved in the catalytic ammoxidation process. Therefore, the ammoxidation of paraffins is a redox process, as is of course the well-known olefin ammoxidation process.     

Sensitivity analysis of complex embedded real-time systems

The robustness of an architecture to changes is a major concern in the design of efficient and reliable state-of-the-art embedded real-time systems. Robustness is important during design process to identify if and in how far a system can accommodate later changes or updates, or whether it can be reused in a next generation product. In the product life-cycle, robustness helps the designer to perform changes as a result of product updates, integration of new components and subsystems, or modifications of the environment. In this paper we determine robustness as a performance reserve, the slack in performance before a system fails to meet timing requirements. This is measured as design sensitivity. Due to complex component interactions, resource sharing and functional dependencies, one-dimensional sensitivity analysis might not cover all effects that modifications of one system property may have on system performance. One reason is that the variation of one property can also affect the values of other system properties requiring new approaches to keep track of simultaneous parameter changes. In this paper we present a framework for one-dimensional and multi-dimensional sensitivity analysis of real-time systems. The framework is based on compositional analysis that is scalable to large systems. The one-dimensional sensitivity analysis combines a binary search technique with a set of formal equations derived from the real-time scheduling theory. The multi-dimensional sensitivity analysis engine consists of an exact algorithm that extends the one-dimensional approach, and a stochastic algorithm based on evolutionary search techniques.     

Die effiziente Organisation

Definition of the problem The hospital as an organization has undergone substantial changes during recent decades due to reforms in the health care system. There have been necessary and quite helpful modifications; however, some modifications raise the question: what public tasks should hospitals fulfill in the future? The following question, thus, arises: what kind of effectiveness, besides cutting costs, should be achieved by the permanent increase of efficiency in hospitals? Paradoxically spoken, the change of the organization hospital seems to be entailed by economization which at the same time is meant to be a remedy for change. Arguments This article reflects on the process of economization from an ethical perspective using patterns from organizational and institutional theory, e.g., a model to evaluate levels of economization contributed by the French sociologist Pierre Bourdieu, applied in this case to German hospitals. Conclusion Market-driven incentives are no answer to the question which goals (i.e., morally, socially, and legally) the health care system should meet. Therefore, public deliberation and performance-orientated shaping of the institutions is required.