On numerical modelling of heat transfer and fluid flow in a scraped surface heat exchanger

Steady state two-dimensional numerical simulation of laminar heat transfer and fluid flow in a scraped surface heat exchanger (SSHE) is presented. Typical SSHE consists of a stator, rotating shaft and scraping blades. Due to symmetry only a quarter of the heat exchanger is modelled. Governing equations for transport of mass, momentum and energy are discretised and solved with the use of commercial CFD code. The results are presented in a nondimensional form for velocity, pressure and temperature distributions. Local and averaged Nusselt number along the stator wall are calculated and depicted in graphs. It was found that the thirty fold increase of the cReynolds number, leads to heat transfer enhancement rate by three times

Application of seismic attributes in petrophysical model construction, Miocene deposits in the Carpathian Foredeep

The aimof this studywas to predict reservoir parameters distribution in Miocene deposits. The area of interest is located in the Carpathian Foredeep, where many deposits of natural gas such as Sędziszów (Zagórzyce), Nosówka and Góra Ropczycka are known. The results of the analysis verified existing gas fields and identified new anomalous zones. The main advantage of presented method is the integration of geological, petrophysical and seismic data. For the purpose of modelling of petrophysical parameters distribution (e.g. porosity, density, gamma ray), results of inversion, well logs and seismic attributes were used. On the basis of structural interpretation of 3D seismic data, the structure framework was built. The entire model was divided into four Miocene's complexes and then split it into layers of 10 m thickness. All used well logging data were scaled to the spatial resolution of the structural model. Estimation of petrophysical parameters was performed using advanced algorithms available in Petrel (Neural Net, Gaussian Random Function Simulation). A number of seismic attributes (e.g. Sweetness, Envelope, Local Flatness, Relative Acoustic Impedance, Dominat Frequency, Chaos, Acoustic Impedance) were used to steer the distribution of petrophysical well data. The study provided information about the distribution of petrophysical properties at every point of the spatial model of Miocene complex. The results show high correlation of seismic attributes and petrophysical properties of the data from the area of Góra Ropczycka–Iwierzyce 3D seismic project. On the basis of all available reservoir information, geobodies have been extracted. Petropysical model prediction is fundamental in understanding clastic reservoirs and should be used for prospect identification

Modelling of EMR data for Fe2+(S=2) ions in a [2Fe-2S] cluster in the reduced ferredoxin

The modelling techniques employed in this study utilize structural data to enable correlation of EMR data – described by the spin Hamiltonian (SH) and optical spectroscopy data – described by the crystal field (CF) Hamiltonian. These techniques enable also to predict magnetic and spectroscopic properties of 3dN ions, especially 3d4 and 3d6 ions, in various systems. Specific applications are considered for [Fe2+ and Fe3+] binuclear centres in [2Fe-2S] cluster in the reduced ferredoxin and related biological molecules. The background for model calculations of the zero-field splitting (ZFS) parameters and/or crystal field parameters and the capabilities of the two major techniques used will be presented in the full paper. Here, we present preliminary results of the microscopic spin Hamiltonian (MSH) modelling for Fe2+ (3d6) ions in the reduced ferredoxin

Spin Hamiltonian parameters for Co²⁺ ions in PbMoO₄ crystal - interplay between the fictitious spin S'=1/2 and the effective spin S̃ =3/2

The interplay between the fictitious spin S' = 1/2 and the effective spin S̃=3/2 for Co²⁺(3d⁷) ions is considered. The available experimental data on the Ze g_{i}' factors for the two Co²⁺ complexes in PbMoO₄ obtained using the fictitious "spin" S'=1/2 description serve for determination of the Zeeman g_{i} factors corresponding to the effective spin S̃ =3/2. The second-rank zero-field splitting parameters D and E (S̃ = 3/2) are also indirectly determined from the experimental EMR data by employing the formulas arising from projection of the g_{i}(S̃=3/2) factors onto the g_{i}'(S' = 1/2) factors. The so-determined second-rank zero-field splitting parameters and g_{i}(S̃ = 3/2) factors will enable comparison with the respective quantities obtained in a subsequent paper using a combined modeling approach