The Shapley value for bicooperative games

The aim of the present paper is to study a one-point solution concept for bicooperative games. For these games introduced by Bilbao (2000), we define a one-point solution called the Shapley value, since this value can be interpreted in a similar way to the classical Shapley value for cooperative games. The main result of the paper is an axiomatic characterization of this value.Bicooperative games, Shapley value.

Probabilistic values for bicooperative games

The present paper develops some general conditions under which we analize the bicooperative games introduced by Bilbao (2000). We define the probabilistic values for these games and observe in detail the axioms that characterize such values. Following the work of Weber (1988), these axioms are sequentially introduced observing how they have repercussions on the probabilistic value expression. Also, we introduce the compatible-order values and show the relationship between these values and the efficiency values such that their components are probabilistic values.Bicooperative games, Probabilistic values, Compatible-order values

On the regularity of the covariance matrix of a discretized scalar field on the sphere

We present a comprehensive study of the regularity of the covariance matrix of a discretized field on the sphere. In a particular situation, the rank of the matrix depends on the number of pixels, the number of spherical harmonics, the symmetries of the pixelization scheme and the presence of a mask. Taking into account the above mentioned components, we provide analytical expressions that constrain the rank of the matrix. They are obtained by expanding the determinant of the covariance matrix as a sum of determinants of matrices made up of spherical harmonics. We investigate these constraints for five different pixelizations that have been used in the context of Cosmic Microwave Background (CMB) data analysis: Cube, Icosahedron, Igloo, GLESP and HEALPix, finding that, at least in the considered cases, the HEALPix pixelization tends to provide a covariance matrix with a rank closer to the maximum expected theoretical value than the other pixelizations. The effect of the propagation of numerical errors in the regularity of the covariance matrix is also studied for different computational precisions, as well as the effect of adding a certain level of noise in order to regularize the matrix. In addition, we investigate the application of the previous results to a particular example that requires the inversion of the covariance matrix: the estimation of the CMB temperature power spectrum through the Quadratic Maximum Likelihood algorithm. Finally, some general considerations in order to achieve a regular covariance matrix are also presented.Comment: 36 pages, 12 figures; minor changes in the text, matches published versio

CH3SH conversion in a tubular flow reactor. Experiments and kinetic modelling

The use of non-conventional fuel sources, such as shale gas, brings new research requisites for its proper use in an environmental friendly manner. In this context, shale gas may include different sulphur containing compounds, such as methanethiol, that is also formed as intermediate during sulphur containing residues processing. The present work includes an experimental and kinetic modelling study of the oxidation of methanethiol, CH3SH, in a quartz flow tubular reactor at atmospheric pressure and in the 300–1400 K temperature range. The influence of the temperature, the O2 concentration and the presence of H2O on the conversion regime of CH3SH and the formation of different compounds has been analysed. The experimental results have been interpreted in terms of a detailed gas-phase mechanism compiled in the present work, and the elementary steps involved in the conversion of CH3SH have been identified. In general, oxidation of CH3SH is favoured by both oxygen level and temperature, while the presence of H2O does not modify the CH3SH conversion profile. The main sulphur containing products are SO2, H2S and CS2, pointing to a significant role of other products, apart from SO2, for the control of pollutant emissions

2-methylfuran Oxidation in the Absence and Presence of NO

2-methylfuran (2-MF) has become of interest as biofuel because of its properties and the improvement in its production method, and also because it is an important intermediate in the conversion of 2, 5-dimethylfuran. In this research, an experimental and kinetic modelling study of the oxidation of 2-MF in the absence and presence of NO has been performed in an atmospheric pressure laboratory installation. The experiments were performed in a flow reactor and covered the temperature range from 800 to 1400 K, for mixtures from very fuel-rich to very fuel-lean, highly diluted in nitrogen. The inlet 2-MF concentration was 100 ppm. In the experiments in the presence of NO, the inlet NO concentration was 900 ppm. An interpretation of the experimental results was performed through a gas-phase chemical kinetic model. A reasonable agreement between the experimental trends and the modelling data is obtained. The results of the concentration profile of 2-MF as a function of temperature indicate that, both in the absence and in the presence of NO, the onset of 2-MF consumption is shifted to lower temperatures only under fuel-lean and very fuel-lean conditions. Furthermore, under these conditions the presence of NO also shifts the onset of 2-MF consumption to lower temperatures. The effect of the 2-MF presence on the NO reduction varies with the oxygen concentration. It is seen that under very fuel-rich and stoichiometric conditions NO is reduced basically by reburn reactions, while under fuel-lean and very fuel-lean conditions, the NO-NO2 interconversion appears to be dominant

Interaction soot-SO2. Experimental and kinetic analysis

This study aims to evaluate the capability of SO2 to interact with soot and to determine the kinetics of this reaction under conditions of interest for combustion. The conditions of the soot reactivity experiments were: 1% SO2 with nitrogen to balance, around 10 mg of soot, and different reaction temperatures for each run: 1275, 1325, 1375, 1425, and 1475 K. Results demonstrate that SO2 does interact with soot. The evaluation of the soot reactivity has been based on the calculation of the time for the complete conversion of carbon through the employment of the Shrinking Core Model equations for decreasing size particle with chemical reaction control. The reactivity of soot with SO2 increased by a factor of about 3 when increasing the reaction temperature of the test from 1275 K to 1475 K. Kinetics in terms of Arrhenius parameters showed that the activation energy of the interaction of soot with SO2 was around 82 kJ/mol

Analysis of the regional pattern of sea level change due to ocean dynamics and density changes for 1993-2099 in observations and CMIP5 AOGCMs

Predictions of twenty-first century sea level change show strong regional variation. Regional sea level change observed by satellite altimetry since 1993 is also not spatially homogenous. By comparison with historical and pre-industrial control simulations using the atmosphere–ocean general circulation models (AOGCMs) of the CMIP5 project, we conclude that the observed pattern is generally dominated by unforced (internal generated) variability, although some regions, especially in the Southern Ocean, may already show an externally forced response. Simulated unforced variability cannot explain the observed trends in the tropical Pacific, but we suggest that this is due to inadequate simulation of variability by CMIP5 AOGCMs, rather than evidence of anthropogenic change. We apply the method of pattern scaling to projections of sea level change and show that it gives accurate estimates of future local sea level change in response to anthropogenic forcing as simulated by the AOGCMs under RCP scenarios, implying that the pattern will remain stable in future decades. We note, however, that use of a single integration to evaluate the performance of the pattern-scaling method tends to exaggerate its accuracy. We find that ocean volume mean temperature is generally a better predictor than global mean surface temperature of the magnitude of sea level change, and that the pattern is very similar under the different RCPs for a given model. We determine that the forced signal will be detectable above the noise of unforced internal variability within the next decade globally and may already be detectable in the tropical Atlantic

Experimental and simulation study of the high pressure oxidation of dimethyl carbonate

An experimental and modeling study of the oxidation at high pressure of dimethyl carbonate (DMC) has been performed in a quartz tubular flow reactor. Experimental and simulated concentrations of DMC, CO, CO2 and H2 have been obtained for different temperatures (500–1073 K), pressures (20, 40, and 60 atm) and stoichiometries (λ = 0.7, 1, and 35). Both pressure and concentration of oxygen are important parameters for conversion of DMC. The simulations have been carried out using a detailed kinetic mechanism previously developed by the research group. In general, the model is able to reproduce the experimental trends of the different concentration profiles, although some discrepancies are observed between experimental and simulation results. The performance of the model was also evaluated through the simulation of literature data of the oxidation of DMC at atmospheric pressure in a flow reactor and of the DMC ignition delay times under low and high pressures. In this sense, this work contributes to the knowledge of the combustion process of DMC, by providing new experimental data on the conversion of DMC at high pressures and using a kinetic model for the interpretation of the results

Effect of H2S on the S-PAH formation during ethylene pyrolysis

The effect of the H2S presence on the formation of six different sulphurated polycyclic hydrocarbons (S-PAH), during the pyrolysis of ethylene-H2S mixtures, has been studied in a tubular flow reactor installation. Experiments with different inlet H2S concentrations (0.3, 0.5 and 1%) and temperatures of reaction (between 1075 and 1475 K) have been carried out. The 16 compounds that the Environmental Protection Agency (EPA) has stated as EPA-PAH priority pollutants were also analysed. EPA-PAH compounds were the majority of quantified PAH, and also S-PAH were found and quantified. For temperatures studied, the S-PAH/EPA-PAH ratio values showed a maximum value at 1075 K and a minimum value at 1175 K. With respect to the effect of the inlet concentration of H2S, the S-PAH/EPA-PAH ratio values increased with the increase of the H2S concentration