Dynamic pricing of wind futures

Daily average wind speeds are dynamically modelled by a continuous-time autoregressive model with seasonal mean and volatility. Futures prices based on an index of aggregated wind speeds are derived, and it is shown that the Samuelson effect breaks down. The volatility of these futures will decrease when approaching maturity, an effect which is explained by the memory in higher-order autoregressive models.     

Thiophene-based hydrazones as hole-transporting materials

The synthesis, optical, thermal and photoelectrical properties of thiophene-based hydrazones are reported. The HOMO levels in a solid state of thiophene-based hydrazones measured by the electron photoemission technique are ?5.25 eV and ?5.28 eV. Hole-drift mobilities of the solid solutions in bisphenol-Z polycarbonate (PC-Z) of the synthesized hydrazones were studied by the time-of-flight technique. Room temperature hole mobilities in the solid solution of thiophene-2-carbaldehyde N,N-diphenylhydrazone in PC-Z exceeded 10^?5 cm²/(V s) at high electric fields.     

Interactions between flavour release and rheological properties in model custard desserts: Effect of starch concentration and milk fat

The influence of the concentration of various reagents and of the storage time on the flavour release of custard desserts was evaluated by headspace solid-phase microextraction and supported by rheological measurements. The presence of milk fat induced a significant decrease of the headspace concentration of flavour compounds, mainly due to hydrophobic matrix–flavour interactions. An elevated starch concentration enhanced the strength of the custard gels considerably. However, the increasing starch concentration resulted in an increased flavour release at low flavour concentrations, while a tendency to flavour retention was noted at higher flavour concentrations. During storage time, a denser network was formed as shown by rheological measurements, but no significant difference in flavour release was noted upon storage (three days). These results show that the complex interactions between flavour compounds and the food matrix in a model custard are difficult to predict and have to be carefully evaluated by a combination of rheological parameters and physicochemical interactions.     

High resolution two-dimensional electrophoresis as a tool to differentiate wild from farmed cod (Gadus morhua) and to assess the protein composition of klipfish

Tris and CHAPS–urea extracts from wild and farmed cod muscle and from rehydrated cod klipfish fillets were analyzed by one (1DE) and two-dimensional electrophoresis (2DE). 2DE maps of tris extracts from farmed cod differed from the wild in a series of spots of Mw 35 and 45 kDa. The CHAPS–urea extracts from farmed cod had a several spots of Mw between 100 and 45 kDa, which were hardly detectable in wild cod and very prominent in klipfish. Klipfish was clearly different from the other samples: the myosin heavy chain was hardly detectable in these samples, and the tris extracts contained fewer, and the CHAPS–urea more spots than the corresponding extracts from the raw muscles. Further identification of these potentially diagnostic spots will make it easier the differentiation of farmed from wild cod and the evaluation of klipfish processing on the protein content of the product.     

A multiple criteria evaluation of multi-family apartment block's maintenance contractors: I—Model for maintenance contractor evaluation and the determination of its selection criteria

The paper presents a model that describes the process of selecting dwelling maintenance contractors. The model is based on a multi-criteria evaluation of maintenance contractors, the determination of their utility level for the building's users and a bid price in negotiations that are made according to the results of the multiple criteria analysis. The proposed model could further be applied to plan dwelling maintenance operations. The criteria of maintenance contractor evaluation are selected by taking into consideration the interests and goals of the building's users as well as factors that influence the process of maintenance's efficiency. The correlation of the criteria characterizing maintenance contractors from various perspectives was determined.     

Spectroscopic Characterization of Supersonic Molecular Beams

A general spectroscopic method is described by which samples prepared in supersonic molecular beams can be characterized independently in their ground and excited electronic states. The centerpiece of this experiment is a Fourier transform spectrometer operating at high resolution in the infrared, visible, and ultraviolet. This method is illustrated with studies of the NO₂ and OClO radicals prepared in supersonic molecular beams at temperatures and pressures characteristic of the Earth's atmosphere. This general spectroscopic method is discussed by analogy with low- and high-resolution studies of electronic states which in limited cases have been used to characterize sample conditions in supersonic molecular beam experiments.     

Evaluation of corrosion defects in oil pipelines based on the approaches of fracture mechanics

We study the development of corrosion defects in an industrial oil pipeline. Defects appearing in the pipeline after 5 and 10 yr of operation are measured by the ultrasonic method. It is shown that, after 10 yr of operation, the pipe wall becomes thinner by 22% (as compared with its initial thickness). To evaluate the defectiveness of state of the pipeline, we use the concepts of J -integral and crack-opening displacement δ. The experimental data on corrosion defects are used to find the values of J-integral.     

Codeposition of copper and tin from acid sulphate solutions containing polyether sintanol DS-10 and benzaldehyde

Cu(II) and Sn(II) reduction in acid sulphate solutions containing polyether laprol DS-10 and benzaldehyde (BA) was studied by means of impedance, voltammetric, XPS and XRD techniques. Both additives demonstrate weak surface activity on copper substrate in Cu(II) solutions in the absence of halide impurities. In contrast, their effect is overwhelmingly higher in the Sn|Sn(II) system. The additives induce a significant increase in Sn-electrode impedance and simultaneous strong inhibition of Sn(II) reduction over a wide range of cathodic polarizations. The effects of sintanol and BA in mixed Cu(II) and Sn(II) solutions demonstrate a kind of synergism. Underpotential deposition of tin on foreign (copper) substrate is observed at potentials more positive than the equilibrium potential of the Sn|Sn²⁺ system. Incorporation of tin into the Cu crystalline lattice results in the formation of multiphase material containing pure copper, α-CuSn phase, and intermediate hexagonal hcp phase. Formation of the pure tin phase occurs at more negative potentials and results in a strong inhibitive adsorption that manifests itself in the development of a deep voltammetric minimum. The tin content in the coatings depends on BA concentration and, particularly, on the electrode potential.     

Production of synthesis gas from propane using thermal water vapor plasma

In this work, an experimental plasma-chemical reactor equipped with a water vapor plasma torch was used for catalyst-free thermal plasma reforming of propane to produce a synthesis gas. Thermal arc discharge plasma (a mixture of water vapor and argon) was generated at atmospheric pressure.