Gravitational corrections to the Euler-Heisenberg Lagrangian

We use the worldline formalism for calculating the one-loop effective action for the Einstein-Maxwell background induced by charged scalars or spinors, in the limit of low energy and weak gravitational field but treating the electromagnetic field nonperturbatively. The effective action is obtained in a form which generalizes the standard proper-time representation of the Euler-Heisenberg Lagrangian. We compare with previous work and discuss possible applications.Comment: 33 pages, 2 figure

On the role of heuristics: Experimental evidence on inflation dynamics

We carry out an experiment on a macroeconomic price setting game where prices are complements. Despite relevant information being common knowledge and price flexibility we observe significant deviation from equilibrium prices and history dependence. In a first treatment we observe that equilibrium values were obtained in the long run but at the cost of a very slow adjustment and thus history dependence. By reporting a business indicator in a simpler form, subjects were given the chance to coordinate their prices by help of a heuristic in a second treatment. This option was widely taken, bringing about excess volatility and a deviation from equilibrium even in the long run. In a third treatment with staggered pricing we observe, contrary to theoretical predictions, the one-round ahead (publicly known) shock is significant, but future inflation is not. Our findings cast light on price dynamics when subjects have limited computational capacities. --Inflation Persistence,Staggered Prices,Sticky Reasoning,New Keynesian Phillips Curve

L-Sol : Gebäudeenergie-Konzept basierend auf PVT-Modulen

Das System L-Sol zeigt eine höhere System-Jahresarbeitszahl und ähnliche Gesamtkosten wie ein Luft-Wasser-Wärmepumpen-System. Es verursacht aber keine Lärmemissionen und lässt sich gut optimieren bezüglich PV-Eigenverbrauch

Integrated zone picking and vehicle routing operations with restricted intermediate storage

The competitiveness of a retailer is highly dependent on an efficient distribution system. This is especially true for the supply of stores from distribution centers. Stores ask for high flexibility when it comes to their supply. This means that fast order processing is essential. Order processing affects different subsystems at the distribution center: Orders are picked in multiple picking zones, transferred to intermediate storage, and delivered via dedicated tours. These processing steps are highly interdependent. The schedule for picking needs to be synchronized with the routing decisions to ensure availability of the delivery orders at the DC’s loading docks when their associated tours are scheduled. Concurrently, intermediate storage represents a bottleneck as capacities for order storage are limited. The simultaneous planning of picking and routing operations with restricted intermediate storage is therefore relevant for retail practice but has not so far been considered within an integrated planning approach. Our work addresses this task and discusses an integrated zone picking and vehicle routing problem with restricted intermediate storage. We present a comprehensive model formulation and introduce a general variable neighborhood search for simultaneous consideration of the given planning stages. We also present two alternative sequential approaches that are motivated by the prevailing planning situation in industry. Numerical experiments that we have conducted show the need for an integrated planning approach to obtain practicable results. Further, we identify the impact of the main problem characteristics on the overall planning problem and provide valuable insights for the application of this approach in industry

Effects of solar evolution on finite acquisition time of Fabry-Perot-Interferometers in high resolution solar physics

The imaging spectro-polarimeter VTF (Visible Tunable Filter) will be operated at the Daniel K. Inouye Solar Telescope (DKIST). Due to its capability of resolving dynamic fine structure of smaller than 0.05'', the finite acquisition time of typically 11 s affects the measurement process and potentially causes errors in deduced physical parameters. We estimate those errors and investigate ways of minimising them. We mimic the solar surface using a magneto-hydrodynamic simulation with a spatially averaged vertical field strength of 200 G. We simulate the measurement process scanning through successive wavelength points with a temporal cadence of 1 s. We synthesise FeI 617.3 nm. Besides the classical composition of the line profile, we introduce a novel method in which the intensity in each wavelength point is normalised using the simultaneous continuum intensity. Milne-Eddington inversions are used to infer the line-of-sight velocity, v(los), and the vertical (longitudinal) component of the magnetic field, B(los). We quantify systematic errors, defining the temporal average of the simulation during the measurement as the truth. We find that with the classical composition of the line profiles, errors exceed the sensitivity for v(los) and in filigree regions also for B(los). The novel method that includes normalisation reduces the measurement errors in all cases. Spatial binning without reducing the acquisition time decreases the measurement error slightly. The evolutionary time-scale in inter-granular lanes, in particular in areas with magnetic features (filigree), is shorter than the time-scale within granules. Hence less accumulations could be used for strong magnetic field in inter-granular lanes and more accumulations could be used for the weak granular magnetic fields. As a key result, we suggest to include the novel method of normalisation in corresponding data pipelines.Comment: 11 pages, 11 figures, accepted for publication in A&

L-Sol – heating system with PVT-collectors as single heat source for a brine-water heat pump

The building sector has a huge potential for reducing greenhouse gas emission without the need of a higher sufficiency. The key is to build and retrofit buildings with good envelopes as well as choosing efficient heating systems. A heating system with a brine-water heat pump and PVT collectors as single heat source is suggested here as an alternative to an air-water heat pump system for single family houses. In the system simulations performed, the PVT-heat pump System ("L-Sol") is more efficient than an air-water heat pump system and still affordable. As the System L-Sol produces heat and electricity on the same area it saves space, disadvantages like noise emission of air-water heat pumps or costly drilling of bore holes are omitted. The system has been optimized in terms of efficiency by testing different dimensioning of the components and regarding the grid purchase by optimizing the system control

Penetration and effectiveness of micronized copper in refractory wood species

The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP), which is being impregnated with micronized copper (MC) wood preservatives since 2006. These formulations are composed of copper (Cu) carbonate particles (CuCO3 center dot Cu(OH)(2)), with sizes ranging from 1 nm to 250 mu m, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3 center dot Cu(OH)(2) particles that successively release Cu2+ ions (reservoir effect). The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA) in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect

L-SOL : Heizungssystem mit PVT als Quelle für eine Wärmepumpe

Schlussbericht BFE Projekt L-SolWith the use of PVT collectors, (photovoltaic) electricity as well as (solar) heat can be produced within the same area. This allows for a better utilization of a given roof area. In the L-Sol project, a novel system that uses PVT collectors to produce heat for single-family houses was investigated The PVT collectors deliver both electricity and heat for the operation of a heat pump. A main characteristic of the system is a thermal storage tank (“cold water storage”) between the PVT collectors and the heat pump. This storage tank acts as the source for the heat pump. It was shown that the L-Sol concept makes sense in ecologic as well as in economic terms. For new buildings and old, energetically renovated ones, electricity consumption is 5 to 30 % lower than with the use of an air-water heat pump. During winter, grid purchase is 3 to 11 % below that of an air-water heat pump system combined with PV modules. However, it is difficult to achieve the low costs of an air-water heat pump system. In the L-Sol system, the investment costs for the PVT system (collectors and installation) are the main cost component. Through savings on the collector costs – mainly by using collectors that consist of “normal” PV modules with a retrofitted heat exchanger on the rear side – total life-cycle costs over 20 years can be reduced to a level similar to that of an air-water heat pump system while maintaining the ecological advantages. On top of the improved system efficiency, the L-Sol system’s main advantage over an air-water heat pump system is the lack of noise emissions on the outside of the building. Compared to systems that are using a combination of PVT collectors and either a geothermal storage (2-Sol) or an ice storage, the L-Sol system offers reduced life-cycle costs. Furthermore, it requires no extensive ground works or special building permits. It is therefore also well suited for replacing fossil heating systems in existing buildings. In an in-depth simulation study, main influence factors on the system efficiency were identified and possibilities to reduce the amount of electricity purchased from the grid were shown. The controls of the heat pump were adapted such that the heat pump is purposefully switched on to heat up und overheat the thermal storage for space heating and domestic warm water when there is surplus electricity from the PVT system. Another possibility to reduce grid purchase is to do the heating-up of the space heating buffer mainly during daytime and disable it at night as long as the comfort requirements are not neglected. A combination of these two control approaches can lead to an electricity self-consumption ratio of 45 %, compared to around 20 % when using standard controls. On top of these adaptations of the control system, adding a battery storage can further increase the level of self-sufficiency. With a battery storage of 10 kWh capacity, the self-consumption ratio can be increased to 55 %. In certain summer months, 100 % self-sufficiency is possible. The high energy demand and the low energy production during phases of bad weather can be buffered by a well-dimensioned thermal storage between the PVT collectors and the heat pump. By adding an additional hydraulic circuit, this storage can be used to cool down the building during summer. The heat that is extracted from the building is either used for domestic hot water generation or it is given off to the environment via the PVT collectors at night. For easy system dimensioning, so-called dimensioning matrices were created. An interested party can use them to estimate a useful system dimensioning for their house and quickly decide whether the L-Sol system could be an option that is worth a more detailed consideration. Depending on the heating energy demand and the flow temperature of the heating circuit, a typical system for a single-family house consists of 15 to 30 uncovered PVT collector modules and a cold water storage with a volume of 1’000 to 2’000 l. Furthermore, it includes a heat pump as well as a warm storage, e.g. a 600-l combined storage.Mit PVT-Kollektoren wird auf derselben Fläche sowohl (PV-)Strom als auch (solare) Wärme gewonnen. Dies erlaubt eine bessere Ausnutzung der Dachflächen. Im Projekt L-Sol wurde ein neuartiges System untersucht, welches die Wärme für Einfamilienhäuser aus PVT-Kollektoren erzeugt. Die PVT-Kollektoren liefern dabei sowohl Strom als auch Wärme für die Wärmepumpe. Charakteristisch für das System ist ein Pufferspeicher («Kaltwasser-Speicher») zwischen den PVT-Kollektoren und der Wärmepumpe, welcher als Quelle für die Wärmepumpe dient. Es zeigte sich, dass das Konzept L-Sol sowohl ökologisch als auch ökonomisch sinnvoll ist. Der Strombedarf ist bei Neubauten und energetisch sanierten Einfamilienhäusern jeweils 5 bis 30 % geringer als beim Einsatz einer Luft-Wasser-Wärmepumpe. In den Wintermonaten liegt der Netzbezug 3 bis 11 % unter dem eines Luft-Wasser-Wärmepumpensystem kombiniert mit einer PV-Anlage. Es ist jedoch schwierig, die tiefen Kosten eines Luft-Wasser-Wärmepumpensystems zu erreichen. Im L-Sol-System stellen die Investitionskosten für die PVT-Anlage (Kollektoren inklusive Installation) den grössten Posten dar. Durch Einsparungen bei den Kollektorkosten – insbesondere durch den Einsatz von mit Wärmetauschern nachgerüsteten «normalen» PV-Modulen - lassen sich die Gesamtkosten über 20 Jahre unter Beibehaltung der ökologischen Vorteile auf das Niveau eines Luft-Wasser-Wärmepumpensystems senken. Neben der höheren Systemeffizienz besteht der Hauptvorteil des L-Sol-Systems gegenüber einem System mit einer Luft-Wasser-Wärmepumpe in den wegfallenden Lärmemissionen im Aussenbereich. Verglichen mit Systemen, die PVT-Kollektoren in Kombination mit einer Erdwärmesonde (2-Sol) oder einem Eisspeicher verwenden, weist das L-Sol-System geringere Lebenszykluskosten auf. Ausserdem erfordert es keine umfassenden Bodenarbeiten oder besondere Bewilligungen. Es eignet sich deshalb auch gut für den Ersatz von fossilen Heizungssystemen in bestehenden Gebäuden. In einer vertieften Simulationsstudie wurden wesentliche Einflussfaktoren auf die Systemeffizienz identifiziert und Möglichkeiten aufgezeigt, wie der Strombezug aus dem Netz verringert werden kann. Die Steuerung der Wärmepumpe wurde so angepasst, dass sie bei einem Stromüberschuss aus der PVT-Anlage gezielt eingeschaltet wird, um die Speicher für Warmwasser und Heizung aufzuheizen oder zu überhitzen. Eine weitere Möglichkeit zur Reduktion des Netzbezugs besteht darin, die Beladung des Heizpufferspeichers überwiegend am Tag durchzuführen und in der Nacht zu sperren, sofern keine Komfortanforderungen verletzt werden. Durch Kombination dieser beiden Steuerstrategien kann der Eigenverbrauchsanteil des Stromes auf rund 45 % gesteigert werden, verglichen mit rund 20 % bei Verwendung einer Standardsteuerung. Zusätzlich zu diesen Steuerungsanpassungen lässt sich durch die Einbindung eines Batteriespeichers der Autarkiegrad weiter steigern. Mit einem Batteriespeicher von 10 kWh Kapazität kann ein Autarkiegrad von 55 % erreicht werden. In einzelnen Sommermonaten ist damit eine 100-prozentige Autarkie möglich. Der hohe Energiebedarf und der geringe Energieertrag während kurzen Schlechtwetterphasen können durch eine entsprechende Grösse des Speichers zwischen PVT-Kollektoren und Wärmepumpe gepuffert werden. Durch das Hinzufügen eines zusätzlichen hydraulischen Kreislaufs kann derselbe Speicher im Sommer verwendet werden um das Gebäude zu kühlen. Die dem Gebäude entnommene Wärme wird dabei zum einen für die Brauchwarmwasser-Erwärmung verwendet und zum anderen nachts über die PVT-Kollektoren an die Umgebung abgegeben. Zur einfachen System-Dimensionierung wurde eine Dimensionierungsmatrix erstellt. Anhand dieser Matrix können Interessenten für ihre Häuser sinnvolle Systemdimensionierungen abschätzen und somit beurteilen, ob das System L-Sol im betrachteten Fall für eine genauere Betrachtung in Frage kommt. Je nach Heizwärmebedarf und Heizkreis-Vorlauftemperatur besteht ein typisches System für ein Einfamilienhaus aus 15 bis 30 unabgedeckten PVT-Kollektor-Modulen und einem Kaltwasser-Speicher von 1'000 bis 2'000 l Volumen. Weiter beinhaltet es eine Wärmepumpe und einen warmen Speicher, z.B. einen 600-l-Kombispeicher

Nudging the poor and the rich : a field study on the distributional effects of green electricity defaults

Choice defaults are an increasingly popular public policy tool. Yet there is little knowledge of the distributional consequences of such nudges for different groups in society. We report results from an elicitation study in the residential electricity market in Switzerland in which we contrast consumers' actual contract choices under an existing default regime with the same consumers' active choices in a survey presenting the same choice-set without any default. We find that the default is successful at curbing greenhouse gas emissions, but it leads poorer households to pay more for their electricity consumption than they would want to, while leaving a significant willingness to pay for green electricity by richer households untapped