22,189 research outputs found

    Liberty, Efficiency, and Law

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    In today’s society there is an increasing demand for renewable energy sources such as sun and wind power. These sources are intermittent, and energy storage is therefore needed to ensure a constant power supply. This report compares pumped hydro energy storage (PHES), compressed air energy storage (CAES), flywheels, batteries, super magnetic energy storage (SMES) and hydrogen energy storage. The opportunities for further development are limited for PHES and CAES in comparison with the other technologies. Lithium-ion batteries and hydrogen energy storage are considered to have the most potential in the future. This is based on the high energy density and the high demand from other industries, the automotive industry in particular. The most limiting factor for both of these technologies is the high cost. Currently there is no method that alone can handle all types of energy storage that is needed, but lithium-ion batteries and hydrogen energy storage will play a key role in the future energy storage. I dagens samhälle efterfrågas allt mer förnybara energikällor så som sol- och vindkraft. Dessa är intermittenta, och för att kunna förlita sig på dessa krävs energilagring. Denna rapport jämför pumpkraftverk, tryckluft (CAES), svänghjul, batterier, supraledande energilager (SMES) och vätgaslagring. Utvecklingsmöjligheterna för pumpkraftverk och tryckluftslager är begränsade jämfört med de andra lagringsmetoderna. De som i denna rapport bedöms ha störst potential i framtiden är litiumjonbatterier och vätgaslagring. Detta beror på att de har hög energitäthet samt att drivkraften för utveckling är stor även i andra branscher, framför allt fordonsbranschen. Största begränsningen för båda teknikerna är kostnaden. I dagsläget finns ingen metod som kan hantera alla typer av energilagring på egen hand, dock <img src="file:///page2image17744" /

    Nitrogen isotope analysis of ammonium and glycine

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    Stable isotope techniques can be used as a tool in nitrogen cycling studies of different ecosystems. The studies are based on measurement of the heavy (15N)- to- light (14N) isotopic ratios of nitrogen in different biospheric pools. Isotope ratio mass spectrometry (IRMS) is the most precise technique to use for analysis of nitrogen isotopic ratios. This thesis deals with the development of methods for compound-specific nitrogen isotope analysis of ammonium and glycine in aqueous solutions and soil extracts using Gas Chromatography - Combustion (GC-C) - IRMS. For ammonium, three different techniques were developed: equilibrium headspace analysis, solid phase microextraction (SPME) and the purge and trap (P & T) technique, which were all based on conversion of ammonium to ammonia with subsequent separation of ammonia for analysis. In the SPME and P & T approaches, custom-made absorbents were used for pre-concentration, followed by thermal desorption into the GC-C-IRMS system. For the equilibrium headspace technique, high precision measurements of the nitrogen isotopic ratio were obtained for concentrations above 420 mg N L-1. With further improvements and the use of suitable equipment, the method has the potential to be used for solutions containing ammonium in the low mg N L-1 range. The SPME technique increased the sensitivity by a factor of » 3 compared to the headspace technique, but was less precise. In addition, the NafionÒ material used for absorption showed a memory effect in the desorption step. With the P & T technique a large variation in the measured isotopic value was observed (using solutions containing 2 mg N L-1) which was due to a non-quantitative thermal desorption. However, with further improvements, the P & T technique has the potential to be used for samples containing below 1.0 µg N, which is a much lower amount than that possible with any method used today. A method for determination of the nitrogen isotopic ratio in free glycine in soil extracts was also developed. By a combination of sample pre-concentration and Isotope Dilution Mass Spectrometry (IDMS), it was possible to determine isotopic ratio in soil extracts with a glycine concentration of only 3 µM (0.042 mg N L-1). The precision obtained was sufficient for use with tracer studies and was higher by an order of magnitude than the precision obtained with conventional GC-MS

    Extension operators via semigroups

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    The Roper--Suffridge extension operator and its modifications are powerful tools to construct biholomorphic mappings with special geometric properties. The first purpose of this paper is to analyze common properties of different extension operators and to define an extension operator for biholomorphic mappings on the open unit ball of an arbitrary complex Banach space. The second purpose is to study extension operators for starlike, spirallike and convex in one direction mappings. In particular, we show that the extension of each spirallike mapping is AA-spirallike for a variety of linear operators AA. Our approach is based on a connection of special classes of biholomorphic mappings defined on the open unit ball of a complex Banach space with semigroups acting on this ball

    Physics with boosted top quarks

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    The production at the LHC of boosted top quarks (top quarks with a transverse momentum that greatly exceeds their rest mass) is a promising process to search for phenomena beyond the Standard Model. In this contribution several examples are discussed of new techniques to reconstruct and identify (tag) the collimated decay topology of the boosted hadronic decays of top quarks. Boosted top reconstruction techniques have been utilized in searches for new physical phenomena. An overview is given of searches by ATLAS, CDF and CMS for heavy new particles decaying into a top and an anti-top quark, vector-like quarks and supersymmetric partners to the top quark.Comment: 8 pages, 6 figures. Proceedings of The Second Annual Conference on Large Hadron Collider Physics, Columbia University, New York, U.S.A, June 2-7, 201

    What determines which children work? Empirical evidence from Kenya

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    This paper determines which children work and how much children work in Kenya. The results show that the educational level of the head of household is important, but it does not matter if the head has primary or higher education. Social norms have a strong effect on the child’s probability of working and access to the labor market is important. The overall finding is not consistent with the view that it is children from the poorest families who work.Child labor; Education; Kenya

    Variation in the Use of Subregional Integration Courts between Business and Human Rights Actors: The Case of the East African Court of Justice

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    Residential energy visualization has increased in popularity during the past years, due to both legislation and an increased focus on the environmental impact of buildings. Meanwhile, the European energy efficiency directive has raised a debate on legislation on individual metering and charging (IMC), in which many negative voices among property owners and developers are being raised. The controversies bring interesting aspects to the analysis of energy visualization and its prerequisite IMC. This thesis will analyze the possibilities and barriers to implement residential energy visualization in new buildings in Stockholm, and the focus will be on local developers' perspective. The purpose of the thesis is to establish Stockholm developers' willingness to pay (WTP) for an IMC and energy visualization solution. The thesis defines perceived utility as the driving force for WTP, and accordingly the developer WTP is analyzed by evaluation of the developers' perceived utility of different technical aspects of an energy visualization solution. The solution has been modularized into three modules; IMC of hot water, IMC of heating and residential visualization. The hypothesis is that utility of the solution modules is perceived differently depending on developer ownership and developer business model; if the developer builds for property management or to sell. The empirical data has been collected through twelve in-depth interviews with developers in Stockholm. The developers were of different size, ownership and with different business models. When looking at the developers from an overall perspective, the analysis shows that there is some willingness to pay for IMC of hot water but none for IMC of heating. It can also be seen that residential visualization is something that the developers have some interest in although the overall WTP is considered low. Although environmental and fairness aspects are often mentioned by the developers in the context of IMC and energy visualization, operational and financial utility seem to be more influential in driving willingness to pay and as these utilities are not perceived, the overall WTP is low or non-existent for IMC and energy visualization. The hypothesis that developers would perceive utility differently depending on ownership or business model, if they build for property management of for sales, could not be proven. There are possibly tendencies for such differences but in this study such patterns were not clear enough to state the hypothesis as true. Additional to the WTP and developer groups, insights and takeaways are presented. The insights and takeaways are based on opportunities and risks that developers perceive with IMC and visualization, as well as requirements they have on the systems

    A white noise approach to insider trading

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    We present a new approach to the optimal portfolio problem for an insider with logarithmic utility. Our method is based on white noise theory, stochastic forward integrals, Hida-Malliavin calculus and the Donsker delta function.Comment: arXiv admin note: text overlap with arXiv:1504.0258

    A type catalogue of Campylopodioideae and Paraleucobryoideae (Musci, Dicranaceae) : part 2, Campylopus

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    All species of Campylopus Brid. are listed, including citations of basionyms and homotypic synonyms, completed by citation of the type specimen and its location, as well as the current use or other uses of the name
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