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After a halt of four years, the n TOF spallation neutron facility at CERN has resumed operation in November 2008 with a new spallation target characterized by an improved safety and engineering design, resulting in a more robust overall performance and e cient cooling. The rst measurement during the 2009 run has aimed at the full characterization of the neutron beam. Several detectors, such as calibrated ssion chambers, the n TOF Silicon Monitor, a Mi- croMegas detector with 10B and 235U samples, as well as liquid and solid scintillators have been used in order to characterize the properties of the neutron uence. The spatial pro le of the beam has been studied with a specially designed \X-Y

This study investigates the relationship between violent conflict, food price, and climate variability at the subnational level. Using disaggregated data on 113 African markets from January 1997 to April 2010, interrelationships between the three variables are analyzed in simultaneous equation models. We find that: (i) a positive feedback exists between food price and violence - higher food prices increase conflict rates within markets and conflict increases food prices; (ii) anomalously dry conditions are associated with increased frequencies of conflict; and (iii) decreased rainfall exerts an indirect effect on conflict through its impact on food prices. These findings suggest that the negative effects of climate variability on conflict can be mitigated by interventions and effective price management in local markets. Creating environments in which food prices are stable and reliable, and markets are accessible and safe, can lower the impacts of both climate change and conflict feedbacks.

Abstract In this paper, the possibility of applying a Power System Stabilizer (PSS) via the governor-turbine system of a generating unit is studied for both single-machine and multimachine power systems. The results of analysis and simulation show that the conventional exciter-based PSS can be used in conjunction with the modern high-speed governor to suppress low-frequency oscillations in power systems. This arrangement of stabilizer possesses better robustness to the changes of power system operating conditions. Furthermore, in the environment of a multimachine power system, the control of PSS on the governor of every generator can be locally synthesized to stabilize the whole system, PSS design becomes much easier and simpler.

This study highlights how Chinese economic development detrimentally impacted water quality in recent decades and how this has been improved by enormous investment in environmental remediation funded by the Chinese government. To our knowledge, this study is the first to describe the variability of surface water quality in inland waters in China, the affecting drivers behind the changes, and how the government-financed conservation actions have impacted water quality. Water quality was found to be poorest in the North and the Northeast China Plain where there is greater coverage of developed land (cities + cropland), a higher gross domestic product (GDP), and higher population density. There are significant positive relationships between the concentration of the annual mean chemical oxygen demand (COD) and the percentage of developed land use (cities + cropland), GDP, and population density in the individual watersheds (p < 0.001). During the past decade, following Chinese government-financed investments in environmental restoration and reforestation, the water quality of Chinese inland waters has improved markedly, which is particularly evident from the significant and exponentially decreasing GDP-normalized COD and ammonium (NH4+-N) concentrations. It is evident that the increasing GDP in China over the past decade did not occur at the continued expense of its inland water ecosystems. This offers hope for the future, also for other industrializing countries, that with appropriate environmental investments a high GDP can be reached and maintained, while simultaneously preserving inland aquatic ecosystems, particularly through management of sewage discharge.

The electric response to an external periodic voltage of small amplitude of dye-sensitized solar cells (DSCs) made up with an alternative architecture has been investigated. DSCs have been fabricated with a reversible sealing structure, based on microfluidic concepts, with a precise control on the geometric parameters of the active chamber. Cells with different electrolyte thicknesses have been characterized, without varying the thickness of the TiO2layer, both under illumination and in dark conditions. Measurements of the electric impedance have been performed in the presence of an external bias ranging from 0 V to 0.8 V. The experimental data have been analyzed in terms of a transmission line model, with two transport channels. The results show that the photovoltaic performances of the microfluidic cell are comparable with those obtained in irreversibly sealed structures, actually demonstrating the reliability of the proposed device.

Vor dem Hintergrund eines zunehmenden globalen Energiebedarfs und der Gefahr einer anthropogenen Störung des Klimasystems durch die Emission von Treibhausgasen gilt es, tragfähige Strategien und Perspektiven für eine nachhaltige Energieversorgung zu entwickeln. Der verstärkten Nutzung erneuerbarer Energien wird dabei vielfach eine Schlüsselrolle zur Bewältigung dieser Herausforderungen zugesprochen. Einer weit verbreiteten Ausschöpfung der auch in Deutschland in großem Maße verfügbaren Potenzialen an regenerativen Energieträgern stehen jedoch häufig noch die damit verbundenen hohen Kosten im Vergleich zu fossilen Energieträgern entgegen. Ziel der vorliegenden Arbeit ist es daher zu untersuchen, welchen Beitrag erneuerbare Energieträger in einem wettbewerblichen Marktumfeld langfristig zur Energieversorgung leisten können und in welchem Umfang erneuerbare Energieträger durch die Internalisierung der Treibhausgasvermeidungskosten in den Energiepreisen profitieren können. Zur Bewertung der Rolle erneuerbarer Energieträger sind mit Blick auf das Gesamtenergiesystem Interdependenzen zwischen der Nutzung erneuerbarer Energieträger und den übrigen Sektoren des Energiesystems zu berücksichtigen. Neben der Vernetzung des Energiesystems in horizontaler Richtung durch Prozessketten über Sektoren hinweg und in vertikaler Richtung durch die Konkurrenz regenerativer mit fossilen Energietechnologien sind dabei auch Kopplungen über Energiepreise, deren Höhe über die Wettbewerbsfähigkeit einer regenerativen Energietechnologie entscheidet, sowie die energie- und preisseitigen Effekte durch Einführung energiepolitischer Instrumente zu beachten. Aufgrund dieser Systemzusammenhänge wird daher ein auf dem Ansatz der linearen Programmierung basierendes intertemporales Energiesystemmodell verwendet, in dem die Energiewirtschaft Deutschlands von der Primär- bis zur Nutzenergie technologisch detailliert abgebildet und hinsichtlich der Systemkosten optimiert wird. Um die Wechselwirkungen innerhalb des Energiesystems aufzuzeigen, werden sich z. T. ergänzende methodische Verfahren entwickelt und eingesetzt. Neben einem Bilanzierungsmodell zur Ermittlung von die Prozessvorketten berücksichtigender Indikatoren zählen hierzu ein auf der Dualitätstheorie beruhendes Verfahren zur Dekomposition der Energie- und Zertifikatspreise, Methoden der Sensitivitätsanalyse zur Ermittlung der fundamentalen preisbestimmenden Faktoren und Techniken der parametrischen Programmierung, um neben Variationen der Modelleingangsdaten Treibhausgasvermeidungskostenkurven und Angebotskurven regenerativ erzeugten Stroms unter Berücksichtigung der systemaren Zusammenhänge im Energiesektor abzuleiten. Mit Hilfe des entwickelten Energiesystemmodells und der Analysemethoden werden die zukünftigen Entwicklungsperspektiven erneuerbarer Energien im deutschen Energiesystem bis zum Jahr 2050 szenariogestützt untersucht. In den Szenarien werden einerseits die mit einer Quote erneuerbarer Energien in der Stromerzeugung verbundenen energie-, kosten- und emissionsseitigen Auswirkungen betrachtet und andererseits der Beitrag erneuerbarer Energien in Konkurrenz mit alternativen Minderungsoptionen zur Erreichung von Treibhausgasminderungszielen dargestellt. Weiterhin werden in simultanen Variationen die Wechselwirkungen zwischen beiden Instrumenten und ihre Auswirkungen speziell auf die Stromerzeugungsstruktur und die Strompreise beleuchtet. Against the background of an increasing global energy demand and the danger of an anthropogenic disturbance of the climate system by the emission of greenhouse gases, it is necessary to develop sustainable strategies and perspectives for the future energy system. The increased usage of renewable sources is identified from many sides as a key element in strategies to overcome these challenges. However, a widely utilisation of the also in Germany large existing potentials of renewable energy carriers is currently still opposed by the associated high costs relative to fossil energy sources. The intention of the submitted thesis is to analyse the contribution of renewable energy sources in the long-run under competitive market conditions to the energy supply and to study the extent to which renewable energy sources can benefit from the internalisation of greenhouse gas abatement costs in the energy prices. To assess the role of renewable energy sources in the context of the entire energy system, interdependencies between the utilisation of renewable energy sources with other aspects and sectors of the energy system have to be taken into account. In addition to the interconnectedness of the energy system in the horizontal direction by process chains across sectors and in the vertical direction by the competition of renewable with conventional fossil technologies also the linkage by energy prices, which serve as benchmark for the competitiveness of a renewable energy technology, and the energy and price related effects caused by the introduction of policy instruments have to be considered. Due to these interactions within the system, a linear programming based dynamic energy system model is used, which depicts technologically detailed the German energy sector from the primary energy supply to the end-use energy demand side and optimises the energy system with respect to its total costs. In order to reveal the interactions and dependencies within the energy system, several partially complementary methodologies have been developed and applied to the model. Apart from a balance model that allows the calculation of specific indicators under consideration of previous process chains, the methodology comprises a method for decomposing energy and certificate prices based on the duality theory, the method of sensitivity analysis to identify the fundamental price-determining activities and parametric programming techniques to derive greenhouse gas abatement cost curves and renewable electricity supply cost curves. With the help of the developed energy system model and analysis tools, the future development perspectives of renewable energy in the German energy system until the year 2050 are studied in various scenarios. In these scenarios, on the one side the energy-, cost- and emission related effects associated with a quota for the electricity production from renewable sources are studied, on the other side the contribution of renewable energy sources to given greenhouse gas abatement targets in competition with alternative abatement measures is examined. Furthermore the interdependencies between these two policy instruments on each other and their effects on the structure of the electricity sector and on the electricity prices are highlighted.