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Abstract: Using ground-based magnetometer data of the April 6–7, 2000, superstorm, we obtained maps of ionospheric and field-aligned currents (FACs). Based on these, we deduced the electrical circuit of the disturbed magnetosphere/ionosphere and a conceptual model of its magnetospheric generators, which supply both hemispheres. This model implies that the generator system creates primarily the Region-1 FACs of Iijima and Potemra at both hemispheres, while the Region-2 and Region-0 FACs form by spreading of the Region-1 currents through the ionosphere. This conclusion is supported by observations. A second prediction of this model turns out to be the following hypothesis, which is also based on the new empirical data. The Region-2 FAC of the dawn side in the Northern Hemisphere is connected with the global dynamo via the asymmetric ring current of the inner magnetosphere, DRP-1. Coming with the DRP-1 into the dusk side, the Region-2 FAC then splits and connects with the dusk side ionosphere of both hemispheres. This way a part of the dawn side Region-1 current becomes connected with the dusk side dynamo of the opposite hemisphere. The intensity of Region-2 and Region-1 FACs of the dusk side is therefore smaller than on the dawn side of this hemisphere, provided that the conductivity in the magnetically conjugated Region-2 ionosphere is larger than the local. Similarly, the dawn–dusk asymmetry of the FAC intensities may also be caused by an inequality of magnetic field and/or pressure gradient in the northern and southern halves of the plasma sheet where DRP-1 flows. The predicted dawn–dusk asymmetry according to such a model is supported by the observations and appears causally connected with an asymmetry between the hemispheres. This conclusion opens a new approach to study these kinds of FAC asymmetries. Further analysis led to the additional conclusion, that the global magnetospheric dynamo works as a voltage generator both during relatively quiet (average) conditions as well as under strong disturbance conditions. [Copyright &y& Elsevier]

Abstract: For combustion in an CO2/O2 atmosphere, known as oxy-combustion, altered combustion rates have to be expected. Previous investigations reported that this can be explained not only with the different thermophysical and radiative properties, but also by the fact that CO2 participates directly in the chemical reactions. This paper presents an experimental study on oxyfuel methane combustion with the aim to investigate the importance of the chemical effects of high CO2 concentrations. Experiments have been carried out in a 25kW furnace for flameless combustion which provides the possibilities to achieve stable combustion of methane within a wide range of oxygen concentrations in the CO2/O2 mixture at constant reactor temperature. This allows to focus on the chemical effects of CO2 by keeping the remaining factors affecting the combustion rate constant. Four different oxidizer mixtures (CO2/O2 and N2/O2 both with 21vol% and 18vol% O2) have been studied by detailed in-furnace measurements for flue gas compositions and temperature. In case of combustion in N2/O2 atmosphere, the CO profiles obtained for different O2 concentrations overlap thus demonstrating that changing the O2 concentration did not affect combustion rates, with keeping the temperature constant. In case of combustion in CO2/O2 atmosphere, the CO concentrations obtained were much higher than those in N2/O2 atmosphere. In contrast to N2/O2, the O2 concentrations had a significant impact on the production and consumption rates of CO in oxyfuel combustion. The results obtained in this work demonstrated that by elimination of the influence of: molar heat capacity, CO2 dissociation, and thermal radiation, it can be estimated that the observed effects of high CO2 concentrations on combustion rates can be attributed to its participation in the chemical reactions. An increase of O2 in oxyfuel led to a reduction of this impact, however, further investigations on the exact mechanism are necessary. [Copyright &y& Elsevier]

Abstract: The empirical field-aligned current (FAC) and plasma convection model on which this paper is based describes the four phases of a typical substorm. 2D maps of the ionospheric electric potential (U) are shown here for the first time for each of these phases. The principal result is the identification of medium-scale ionospheric convection vortices, which are observed in addition to the well-known two large-scale DP2 convection cells. We conclude that these convection vortices are the analogue to the heterogeneities that were found earlier in the spatial distribution of the FAC density. They had been taken into account there in the framework of the conceptual model of magnetospheric generators. This model is extended in the present paper such that it also describes the above-mentioned medium-scale convection vortices. [Copyright &y& Elsevier]

Abstract: Inclusion of trace quantities of heavy metal atoms (Pd) in a ladder-type polymer (PhLPPP) backbone allows transitions between the singlet and the triplet manifolds. Temperature-dependent photoinduced absorption studies of PhLPPP show the triplet–triplet absorption peak (T 1 → T N) at 1.3eV to blue-shift with increasing temperatures, suggesting a localization of the excitons on smaller chain segments with large exchange splitting energy. Furthermore, solar cells were fabricated using PhLPPP as the donor material; on an average the power conversion efficiencies of PhLPPP-based solar cells were 3–10 times greater compared to the ladder-type polymer with no incorporation of Pd atoms. [Copyright &y& Elsevier]

A whole-genome association study of milk production traits: milk yield, protein yield, fat yield, protein percentage, and fat percentage, was performed on the population of Braunvieh cattle. Five hundred and fiftyfour progeny-tested bulls and 36,219 autosomal single nucleotide polymorphism (SNP) markers on 29 Bos taurus autosomes (BTA) were included in the analysis. A principal component analysis was conducted to adjust for the effect of population stratification in the analyzed data set. For the principal component analysis, genome-wide relationships between individuals were calculated. Three different criteria (Horn's test, Kaiser's criterion, and Jolliffe's criterion) were tested to determine the number of significant principal components. Estimation of putative associations between SNP and milk production traits was carried out using a linear regression model in R software (R Foundation for Statistical Computing, Vienna, Austria). Significant principal components, adjusting for population stratification separately for each criterion and family relationships and genotypes at individual SNP were included as fixed effects in the model. The inflation factor λ and quantile-quantile plots were calculated to compare how the different criteria deal with stratification in our mapping population. Based on the analyses on all of the aforementioned criteria, we can conclude that Jolliffe's criterion deals the best with population stratification. Furthermore, significance thresholds for a given genome-wide false discovery rate of 5% were estimated and used for specific traits. Three of the analyzed traits showed genome-wide significant association with SNP. Two SNP had an effect on milk yield on BTA4, 2 SNP affected fat yield on BTA14 and BTA23, and 1 SNP was associated with fat percent on BTA1. Single nucleotide polymorphisms identified in this study as associated with milk production traits will further contribute to the mapping of corresponding quantitative trait loci and investigation of the genes responsible for polymorphisms in milk production traits in dairy cattle. Described comparison of different criteria for determination of significant principal components can provide important information for similar studies in stratified populations. [ABSTRACT FROM AUTHOR]

Abstract: This work is to clarify the underlying mechanisms of burning pulverised coal in a mixture of . The performance of two different burner designs, single central orifice-type (SCO) and single annular orifice-type (SAO), under oxycoal conditions was examined in a down-fired test facility. Based on detailed in-flame measurements, combined with numerical simulations, the main parameters influencing the stability of a pulverised coal swirl flame were investigated. The oxycoal flame was stabilised at the burner quarl by: increasing the O2 concentration above 34vol% without changes to the air-firing burner design and by modifications of the burner geometry thus changing its aerodynamics. The modification of the burner allowed a decrease of the O2 concentrations to 23vol% for SCO burner and to less than 21vol% for SAO burner. Comprehensive measurement data for axial and tangential velocity, flue gas temperature and oxygen concentration for stable oxy-firing at 21vol% O2 is presented. The results reported can be used as a guideline for a development of an industrial swirl burner capable of stable operation in both regimes, namely: air and oxycoal. [Copyright &y& Elsevier]

Abstract: A novel approach to oxycoal flame stabilization has been developed at the Institute of Heat and Mass Transfer at RWTH Aachen University [D. Toporov, M. Förster, R. Kneer, in: Third Int. Conf. on Clean Coal Technologies for Our Future, Cagliari, Sardinia, Italy, 15–17 May 2007]. The swirl burner design and its operating conditions have been adjusted in order to enforce CO formation thus stabilizing the flame and obtaining a full burnout at levels of O2 content in the O2/CO2 mixture similar to those in air. The paper presents results of detailed numerical and experimental investigations of a stable oxy-fired pulverized coal swirl flame (type-2) obtained with a 21 vol% O2 concentration. The combustion tests were performed in a vertical pilot-scale furnace (100 kWth) in the framework of the OXYCOAL-AC research project aiming to develop a membrane-based oxyfuel process. The experimental results concerning gas velocities, gas and particle temperatures, and gas compositions are presented and discussed, focusing on the underlying mechanisms as well as on the aerodynamics of the oxycoal flame. A comparison between measurements and simulations has shown the validity of the numerical method used. The reported data set can be used for validation of numerical models developed for prediction of oxyfuel combustion. [Copyright &y& Elsevier]