Nachtrag: Klimaschutzpolitik

Ergänzend zu dem im ifo Schnelldienst 19/2001 diskutierten Thema »Klimaschutz - ist das Emissionshandelssystem ein effizientes Mittel zur Emissionsverringerung?« sind Prof. Dr. Uwe Schubert und Oliver Percl, Wirtschaftsuniversität Wien, der Ansicht, »dass beim derzeitigen Wissensstand die generellen Vorteile des Emissionshandels potentiell die Nachteile überwiegen könnten, besonders wenn es gelingt, die Rahmenbedingungen ›richtig‹ zu setzen und die Offenheit des Systems für sicherlich notwendige Änderungen zu gewährleisten. Nach Meinung von Prof. Dr. Rüdiger Pethig, Universität Siegen, ist sogar »die Einführung eines weltweiten Handels mit Rechten für Treibhausgasemissionen der einzige gangbare Weg, das Ziel der Stabilisierung des Weltklimas zu erreichen«.Klimaschutz, Umweltbelastung, Klimaforschung, Welt

Noble Metal Complexes of a Bis-Caffeine Containing NHC Ligand

N -Heterocyclic carbenes (NHCs) have seen more and more use over the years. The go-to systems that are usually considered are derivatives of benzimidazole or imidazole. Caffeine possesses an imidazole unit and was already utilized as a carbene-type ligand; however, its use within a tridentate bis-NHC system has—to the best of our knowledge—not been reported so far. The synthesis of the ligand is straightforward and metal complexes are readily available via silver-salt metathesis. A platinum(II) and a palladium(II) complex were isolated and a crystal structure of the former was examined. For the Pt(II) complex, luminescence is observed in solid state as well as in solution

Influence of Cutting Speed in Turning and Force in Subsequent Diamond Smoothing on Magnetic Properties of Steel 100Cr6

Magnetic properties are known to be crucial in the application of electrical steel and they are therefore covered by manifold studies. Other ferromagnetic materials are out of scope in this respect, even if the importance of magnetism of conventional steel is evident. Additionally, there is a contradiction regarding the major influence on magnetic properties. Machining, transport, and storage are possible influencing variables. In the experimental investigations, specimens consisting of the bearing steel 100Cr6 are machined by turning and partly by subsequent diamond smoothing. While machining using several cutting speeds and smoothing forces, the thermoelectrical voltage, current, and the components of the resultant force are recorded. The results show how the nearsurface plastic deformations evolve throughout the machining process. Additionally, it was found that the magnetic properties and other properties of the surface layer are influenced in different ways depending on turning and diamond smoothing parameters. Correlations between in situ and ex situ measured values are shown. This study aims to solve the aforementioned question by quantification of machining impacts of cutting speed in turning and force in diamond smoothing and its dependence on transport and storage

IR Spectroscopy as a Method for Online Electrolyte State Assessment in RFBs

Abstract The transition from fossil to renewable energy sources requires adequate storage technologies due to the intermittency of the supplied energy. With respect to this, organic redox‐flow batteries (ORFBs) represent a promising concept for the storage of electricity on a large scale at economically justifiable costs. However, these storage technologies can only be operated reliably if parameters representing the actual condition of the storage medium (i.e., the electrolyte) can be accurately assessed. These so‐called electrolyte state variables are represented by two key figures of merit: state of charge (SOC), a measure of the amount of charge that the electrolyte currently holds; and state of health (SOH), representing the amount of charge that the electrolyte is able to store given its current condition. The herein presented IR‐based approach is able to simultaneously provide reliable, fast, accurate, and precise estimates for both SOC and SOH parameters at any point in time and independent of the current battery status. The method is able to provide a time resolution in the range of minutes, is independent of the electrolyte temperature and can be applied to nearly all organic‐based redox‐active materials and solvents, while potentially being applicable to inorganic RFBs, such as vanadium‐based systems, as well.Redox‐flow batteries (RFBs) provide a unique and scalable storage solution for green energy. However, they can only be operated safely when parameters representing the battery state are precisely known at any point in time. The presented IR‐spectroscopic method is able to generate accurate and precise estimates for the crucial State‐of‐Charge and State‐of‐Health variables of RFB electrolytes. imag

SQUIRRELnovo : de novo design of a PPARalpha agonist by bioisosteric replacement

Shape complementarity is a compulsory condition for molecular recognition. In our 3D ligand-based virtual screening approach called SQUIRREL, we combine shape-based rigid body alignment with fuzzy pharmacophore scoring. Retrospective validation studies demonstrate the superiority of methods which combine both shape and pharmacophore information on the family of peroxisome proliferator-activated receptors (PPARs). We demonstrate the real-life applicability of SQUIRREL by a prospective virtual screening study, where a potent PPARalpha agonist with an EC50 of 44 nM and 100-fold selectivity against PPARgamma has been identified..

Service Section Design of the EDEN ISS Project

The international EDEN ISS project aims to investigate and validate techniques for plant cultivation in future bioregenerative life support systems. To this end the EDEN ISS project partners aim to design and build the Mobile Test Facility, which consists of two modified 20 foot shipping containers. One of these shipping containers is designated the Service Section and houses the bulk of the subsystem components, such as the Air Management System and Nutrient Delivery System, as well as a rack-sized plant cultivation system, which uses a standard International Space Station payload form factor. The subsystems within the Service Section ensure that the approximately 12.5 m² of cultivation area in the second container, the Future Exploration Greenhouse, have the proper environmental conditions, nutrients and illumination for optimal crop growth. The EDEN ISS project concluded its main design phase with a Critical Design Review in March 2016, thereafter proceeded into the hardware development and procurement phase of the project. This paper describes the final design of the Service Section at the start of the assembly, integration and testing phase, which will run until the complete Mobile Test Facility is shipped to Antarctica, where it arrives in December 2017, for a 12 month space analogue mission

Creep Simulations of Nuclear Fuel Cladding under long term Storage Conditions with TRANSURANUS

Within a joint research project between the Institute for Energy (IE) and the Institute for Transuranium Elements (ITU) on the integrity of spent nuclear fuel cladding the ITU code TRANSURANUS was used to simulate creep of Zircaloy cladding tubes under long term storage conditions. Since TRANSURANUS is designed to model the mechanical, thermal and physical behaviour of fuel rods during reactor operation it was the objective of this study firstly to explore the limitations of the present creep models in TRANSURANUS for the simulation of long term creep processes under dry storage conditions. If the present creep models in TRANSURANUS were found to be inappropriate then the next objective was to formulate the properties of an "ideal" creep model for dry storage. The creep models were compared with creep tests on unirradiated Zircaloy cladding tubes. It turned out that the standard creep model for Zircaloy cladding in TRANSURANUS, the model of Lassmann and Moreno, underestimated the creep strains of the tests significantly. The creep model of Mayuzumi and Onchi, which was designed to model long term creep processes under dry storage conditions, lead to reasonable agreement with the creep tests for temperatures of 350 degrees Celcius and above. It turned out that for the accurate prediction under low-temperature conditions (under 350 degrees Celcius) more sophisticated creep models, which account for a shift in creep mechanisms, are necessary.JRC.F.5-Safety of present nuclear reactor

Kernel learning for ligand-based virtual screening: discovery of a new PPARgamma agonist

Poster presentation at 5th German Conference on Cheminformatics: 23. CIC-Workshop Goslar, Germany. 8-10 November 2009 We demonstrate the theoretical and practical application of modern kernel-based machine learning methods to ligand-based virtual screening by successful prospective screening for novel agonists of the peroxisome proliferator-activated receptor gamma (PPARgamma) [1]. PPARgamma is a nuclear receptor involved in lipid and glucose metabolism, and related to type-2 diabetes and dyslipidemia. Applied methods included a graph kernel designed for molecular similarity analysis [2], kernel principle component analysis [3], multiple kernel learning [4], and, Gaussian process regression [5]. In the machine learning approach to ligand-based virtual screening, one uses the similarity principle [6] to identify potentially active compounds based on their similarity to known reference ligands. Kernel-based machine learning [7] uses the "kernel trick", a systematic approach to the derivation of non-linear versions of linear algorithms like separating hyperplanes and regression. Prerequisites for kernel learning are similarity measures with the mathematical property of positive semidefiniteness (kernels). The iterative similarity optimal assignment graph kernel (ISOAK) [2] is defined directly on the annotated structure graph, and was designed specifically for the comparison of small molecules. In our virtual screening study, its use improved results, e.g., in principle component analysis-based visualization and Gaussian process regression. Following a thorough retrospective validation using a data set of 176 published PPARgamma agonists [8], we screened a vendor library for novel agonists. Subsequent testing of 15 compounds in a cell-based transactivation assay [9] yielded four active compounds. The most interesting hit, a natural product derivative with cyclobutane scaffold, is a full selective PPARgamma agonist (EC50 = 10 ± 0.2 microM, inactive on PPARalpha and PPARbeta/delta at 10 microM). We demonstrate how the interplay of several modern kernel-based machine learning approaches can successfully improve ligand-based virtual screening results