Other-regarding behaviour: Testing guilt- and reciprocity-based models

We analyse two types of belief-dependant models of social preferences: guilt aversion and reciprocity. In particular, we test the relevance of their input variables (second-order beliefs and general dispositions for guilt/reciprocity). The data confirm the predictions of belief-dependant models. Both second-order beliefs and a participant's sensitivity to guilt/reciprocity are relevant for the decisions taken. Second-order beliefs appear to have an inverse U-shaped effect on the extent of kind behaviour.social preferences, other-regarding behaviour, belief-dependent models, experiments, trust game, guilt aversion, beliefs, psychological game theory, emotions, reciprocity

Photoionization in the time and frequency domain

Ultrafast processes in matter, such as the electron emission following light absorption, can now be studied using ultrashort light pulses of attosecond duration ($10^{-18}$s) in the extreme ultraviolet spectral range. The lack of spectral resolution due to the use of short light pulses may raise serious issues in the interpretation of the experimental results and the comparison with detailed theoretical calculations. Here, we determine photoionization time delays in neon atoms over a 40 eV energy range with an interferometric technique combining high temporal and spectral resolution. We spectrally disentangle direct ionization from ionization with shake up, where a second electron is left in an excited state, thus obtaining excellent agreement with theoretical calculations and thereby solving a puzzle raised by seven-year-old measurements. Our experimental approach does not have conceptual limits, allowing us to foresee, with the help of upcoming laser technology, ultra-high resolution time-frequency studies from the visible to the x-ray range.Comment: 5 pages, 4 figure

Temperature dependency of the laminar burning velocity of fuel-rich methane oxygen measurements

First experiments to determine laminar burning velocities of methane-pure oxygen mixtures were carried out in 1932 by Jahn [1] for a wide range of equivalence ratios Φ (0.2 to 2.64) using a Bunsen burner. Since then, new and most important more accurate methods were developed to determine laminar burning velocities. One of these methods, namely the Heat Flux Method, which was introduced by de Goey et al. [2] in 1993, was used in the current work to validate the results for fuel-rich methane oxygen mixtures (Φ = 2.38 to 2.64) as published by Jahn. Regarding the current Heat Flux Bruner setup the range of velocities that can be determined are limited between 9 and 50 cm/s, which also limits the range of investigated equivalence ratios (Φ = 2.38 to 3.03), which is wider as the one investigated by Jahn [1]. Furthermore, the influence of the pre-heating temperature was also investigated by a variation of it from 263 up to 455 K. Based on these experimental data the temperature dependency of laminar burning velocities of fuel-rich methane oxygen mixtures was determined and as a result the coefficient α of the power law correlation SL = SL0 (T/T0)α was calculated. Due to the increase of the laminar burning velocity at higher pre-heating temperatures, the laminar burning velocities could also be determined at equivalence ratios up to a maximum value of Φ = 3.33 (TP = 455 K). The increase in accuracy of measurement methods to determine laminar burning velocities over the last decades [3] leads to an observed decrease in measured flame speeds. This tendency is confirmed in the current experiments, where the determined laminar burning velocities are lower than the ones measured by Jahn [1]. Regarding the temperature dependency of the laminar burning velocity, the results indicate that for the range of investigated equivalence ratios and temperatures (300 K to 455 K) the power law coefficient α was observed to be almost constant

Characterization of uncertainties in atmospheric trace gas inversions using hierarchical Bayesian methods

We present a hierarchical Bayesian method for atmospheric trace gas inversions. This method is used to estimate emissions of trace gases as well as "hyper-parameters" that characterize the probability density functions (PDFs) of the a priori emissions and model-measurement covariances. By exploring the space of "uncertainties in uncertainties", we show that the hierarchical method results in a more complete estimation of emissions and their uncertainties than traditional Bayesian inversions, which rely heavily on expert judgment. We present an analysis that shows the effect of including hyper-parameters, which are themselves informed by the data, and show that this method can serve to reduce the effect of errors in assumptions made about the a priori emissions and model-measurement uncertainties. We then apply this method to the estimation of sulfur hexafluoride (SF6) emissions over 2012 for the regions surrounding four Advanced Global Atmospheric Gases Experiment (AGAGE) stations. We find that improper accounting of model representation uncertainties, in particular, can lead to the derivation of emissions and associated uncertainties that are unrealistic and show that those derived using the hierarchical method are likely to be more representative of the true uncertainties in the system. We demonstrate through this SF6 case study that this method is less sensitive to outliers in the data and to subjective assumptions about a priori emissions and model-measurement uncertainties than traditional methods

Recent and future trends in synthetic greenhouse gas radiative forcing

Atmospheric measurements show that emissions of hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons are now the primary drivers of the positive growth in synthetic greenhouse gas (SGHG) radiative forcing. We infer recent SGHG emissions and examine the impact of future emissions scenarios, with a particular focus on proposals to reduce HFC use under the Montreal Protocol. If these proposals are implemented, overall SGHG radiative forcing could peak at around 355 mW m[superscript −2] in 2020, before declining by approximately 26% by 2050, despite continued growth of fully fluorinated greenhouse gas emissions. Compared to “no HFC policy” projections, this amounts to a reduction in radiative forcing of between 50 and 240 mW m[superscript −2] by 2050 or a cumulative emissions saving equivalent to 0.5 to 2.8 years of CO2 emissions at current levels. However, more complete reporting of global HFC emissions is required, as less than half of global emissions are currently accounted for.Natural Environment Research Council (Great Britain) (Advanced Research Fellowship NE/I021365/1)United States. National Aeronautics and Space Administration (Upper Atmospheric Research Program Grant NNX11AF17G)United States. National Oceanic and Atmospheric Administratio

Numerical evaluation of a novel double-concentric swirl burner for sulfur combustion

A burner system for the efficient and clean combustion of sulfur is introduced, which serves as a key component in a novel solar power cycle using sulfur as chemical storage medium of solar energy. In order to validate the proposed design concept, highly-resolved numerical simulations have been performed. The current setup is operated with a thermal load of 20 kW or power density of 5 MW/m$^{3}$. Two nozzle configurations with different swirl intensities (SI) of the airflow are studied. A large inner recirculation zone is observed for the nozzle with a high SI (HSI), which leads to a strong radial dispersion of the sulfur spray and a broad, short flame in the combustion chamber; although this HSI design is beneficial from the viewpoint of flame stabilization, it causes a large number of sulfur droplets hitting the chamber wall. In contrast, the nozzle design with a low SI (LSI) yields a narrow spray and a long jet flame, with much less droplets hitting the wall. The HSI nozzle shows an overall higher flame temperature compared with the LSI nozzle, which is confirmed to be caused by burning at a higher local fuel equivalence ratio. This is attributed to the strong inner recirculation flow generated by the high swirl intensity, which results in an enhanced evaporation and mixing of sulfur droplets with air. In terms of operability and NOx emission, the LSI burner is preferred due to less sulfur droplets hitting the chamber wall and the lower flame temperature