The influence of membrane CO2 separation on the efficiency of a coal-fired power plant

In this paper, the influence of membrane separation of CO₂ from flue gases and the impacts of the whole CCS process (CO₂ separation and compression) on the performance of a coal-fired power plant are studied. First, the effects of the characteristics of the membrane (selectivity and permeability) and the parameters of the process (feed and permeate pressure) on two indices, CO₂ recovery rate and CO₂ purity are analysed. Next, a method for determining the minimum power loss and efficiency loss of the power plant as a function of these calculated indices is described. Then, the power requirements and efficiency loss (up to 15.4 percentage points) because of the CCS installation are calculated. A method for reducing these losses through the integration of the CCS installation with the power plant is also proposed. The main aims of the integration are heat exchange between media and a decrease in the CO₂ temperature before compression. Implementing this process can result in a significant reduction of the efficiency loss by 8 percentage points.     

Interactions of Amyloid-β with Membrane Proteins

In developing and developed countries, an increasing elderly population is observed. This affects the growing percentage of people struggling with neurodegenerative diseases, including Alzheimer’s disease. Nevertheless, the pathomechanism of this disease is still unknown. This contributes to problems with early diagnosis of the disease as well as with treatment. One of the most popular hypotheses of Alzheimer’s disease is related to the pathological deposition of amyloid-β (Aβ) in the brain of ill people. In this paper, we discuss issues related to Aβ and its relationship in the development of Alzheimer’s disease. The structure of Aβ and its interaction with the cell membrane are discussed. Not only do the extracellular plaques affect nerve cells, but other forms of this peptide as well.     

Analysis of exoskeleton triglycerides ofLeptinotarsa decemlineata say

The exoskeleton triglyceride fraction isolated from the Colorado beetle,Leptinotarsa decemlineata Say, was studied. Analysis of the hydrolysis products and direct capillary column gas chromatography showed that, apart from triglycerides, the fraction contained no diol lipids. The composition of the natural triacylglccerol mixture was assessed by gas chromatography and by field desorption and electron impact mass spectrometry. Triglycerides isolated from the Colorado beetle are typical glycerol triesters, with long chain (mainly oleic or palmitic) fatty acids. The structures of two major components (91%), i.e., trioleoyl glycerol and 1,2-dioleoyl-3-palmitoyl glycerol, were determined.     

Corrosion-passivation processes in a cellular automata based simulation study

A short survey of cellular automata based models for corrosion and passivation phenomena is given. Results of simulations based on the model of spatially separated anodic and cathodic reactions are presented for a cavity development from a point-like damage of a protective layer and from an initially flat unprotected surface. We show some new peculiar examples of the symmetry breaking in the cavity development. The results for the initially flat surface show roughening of the surface at the beginning of the corrosion process. After that, pit merging causes a resmoothing of the surface. An oscillatory behavior of the surface roughness is observed caused by a peninsula formation with subsequent island detachment. These results are obtained in 2D because of computational limitations. We plan simulations in 3D and point out the problems we encounter in their realization.     

Wetting and Interfacial Chemistry of SnZnCu Alloys with Cu and Al Substrates

Wetting of Cu and Al pads by Sn-Zn eutectic-based alloys with 0.5, 1, and 1.5 wt.% of Cu was studied at 250 °C, in the presence of ALU33® flux, with wetting times of 15, 30, 60, and 180 s, respectively. With increasing wetting time the wetting angle decreases only slightly and the angles on Cu pads are higher than those on Al pads. Selected, solidified solder-pad couples were cross-sectioned and subjected to SEM-EDS study of the interfacial microstructure. The results revealed that the microstructure of the SnZnCu/Cu interface is much different from SnZnCu/Al interface. In the first case continuous interlayers are observed while in the latter case there is no interlayer but the alloy dissolves the substrate along grain boundaries.     

Approximation of a multivariable sensor characteristic applied to the carbon monoxide sensor

The transducer applied in sensors and measurement systems often have non-linear characteristics, which may depend on additional factors as temperature, humidity gases flow, etc. Therefore, it is important to find the function describing the dependence between input and output values of a transducer which takes into account all the influencing factors. This paper shows a method which, basing on measured data, allows to establish a multi-variable transducer transfer function.     

Numerical modelling of radiative heat transfer in an internal indirect reforming-type SOFC

The present paper describes numerical modelling of the radiative heat transfer process in the module chamber of an internal indirect reforming-type SOFC. The ability to do internal reforming is one of the characteristics of high-temperature fuel cells, SOFC. As in any high-temperature system, radiative heat transfer is important. In this article, heat transfer between the fuel reformer surface and all other surfaces facing the reformer surfaces is modelled. Governing equations for radiative heat transfer are described using Hottel's zone method. The resulting radiation–conduction conjugate heat transfer problems are numerically solved with a combination of Gauss–Seidel and Newton–Raphson methods. The steam reforming reaction occurring inside the fuel reformer is described using Achenbach model. The obtained results indicate that, for the development of effective indirect internal reforming, the position of the reformer in the module chamber and emissivity of the surfaces of the reformer, cell and other elements in the SOFC module all play a key role.     

Three-dimensional modeling of the I-TevI homing endonuclease catalytic domain, a GIY-YIG superfamily member, using NMR restraints and Monte Carlo dynamics

Using a recent version of the SICHO algorithm for in silicoprotein folding, we made a blind prediction of the tertiarystructure of the N-terminal, independently folded, catalyticdomain (CD) of the I-TevI homing endonuclease, a representativeof the GIY–YIG superfamily of homing endonucleases. Thesecondary structure of the I-TevI CD has been determined usingNMR spectroscopy, but computational sequence analysis failedto detect any protein of known tertiary structure related tothe GIY–YIG nucleases (Kowalski et al., Nucleic AcidsRes., 1999, 27, 2115–2125). To provide further insightinto the structure–function relationships of all GIY–YIGsuperfamily members, including the recently described subfamilyof type II restriction enzymes (Bujnicki et al., Trends Biochem.Sci., 2000, 26, 9–11), we incorporated the experimentallydetermined and predicted secondary and tertiary restraints ina reduced (side chain only) protein model, which was minimizedby Monte Carlo dynamics and simulated annealing. The subsequentlyelaborated full atomic model of the I-TevI CD allows the availableexperimental data to be put into a structural context and suggeststhat the GIY–YIG domain may dimerize in order to bringtogether the conserved residues of the active site.     

Defect Chemistry of (La,Sr)MnO3

Defect-disorder models are derived for undoped and strontium-doped LaMnO₃. A random-defect model and a cluster-defect model are both considered within the regimes that correspond to oxygen deficit and oxygen excess. The models are constructed based on the experimental nonstoichiometry data that was reported by previous researchers. According to both models, the addition of strontium leads to an increase of the concentration of electron holes and oxygen nonstoichiometry. The defect clusters that are predicted by the cluster model have a marked concentration only at very low oxygen partial pressures. Both models are verified against the electrical-conductivity data. A good agreement between the random-defect model and the experimental data is shown.