STRUCTURE AND PROPERTIES OF NANOSIZE NiFe2O4 PREPARED BY TEMPLATE AND PRECIPITATION METHODS

Nanosize NiFe2O4 was prepared by template method and precipitation process using same starting materials. The use of soluble starch in both synthesis routes was investigated. The amount of the used precipitating agent (Na2CO3) for the precipitation approach was selected according to two adopted scenarios based on theoretical and average yield of possible side reaction expressed by the degree of substitution (DS). The results of SEM microstructural analysis of the prepared Ni-ferrite powders demonstrate evident influence of the applied preparation method whereas high-magnification FE-SEM images show very similar fine-grained structures characterized by different size of particles. According to the results of XRD analysis, the obtained ferrite powders exhibit only slight differences in phase composition with calculated crystallite size for template sample d(XRD) = 36 nm and for the both precipitation route samples d(XRD) = 21 nm. Additional sample characterization using Fe-57 Mossbauer spectroscopy supports the findings of the microstructural and XRD analysis. The "clearest" spectrum was obtained for the template sample while the strongest influence of nanocrystalline component was observed for the sample prepared with maximal amount of precipitation agent (DS=3). The room temperature magnetic hysteresis loops, recorded using vibrating sample magnetometer (VSM), are very similar and exhibit characteristic shape with values of magnetic properties within expected range for this type of material

Interaction of p-nitrophenol with lipids at hydrophobic interfaces.

Adsorption of p-nitrophenol (PNP) at two model hydrophobic interfaces, namely at air/solution interface and mercury electrode/solution interface, as well as its interaction with neutral and charged lipids has been studied in monolayers by light reflection spectroscopy and electrochemical methods. Investigations have been performed at pH=10 and pH=11 wher the dissociated form of PNP carrying a negative charge is predominant. In this pH region no accumulation of PNP from bulk solution to the free air/solution interface and slight adsorption at mercury surface was observed. PNP also does not accumulate in neutral phospholipid monolayers spread at the air/solution interface while phospholipid layers formed at mercury by adsorption from the bulk solution cause the inhibition of electrochemical reduction of PNP. The attachment of PNP to the neutral phospholipid layer is enhanced and accelerated at both interfaces by the presence of quarternary ammonium salts in the solution

Microfauna and nannoplankton below the Paleocene/Eocene transition in hemipelagic sediments at the southernslope of Mt. Nanos (NW part of the PaleogeneAdriatic carbonate platform, Slovenia)

This paper describes deeper water clastic to hemipelagic sediments from the Adriatic microcontinent, at the contact zone between the Adriatic and Dinaric carbonate platforms. The flysch section from Mt. Nanos contains a sedimentary sequence deposited close to the Paleocene/Eocene boundary. We dated this section biostratigraphically, reconstructed the paleoenvironments, and established a correlation with the northern part of the central Tethys. Samples were studied for calcareous nannoplankton, planktonic foraminifera, small and large benthic foraminifera, and ostracods. Calcareous nannoplankton assemblages of the Nanos section belong to the Discoaster multiradiatus zone NP 9 in the uppermost Paleocene. Planktonic foraminiferal assemblages allow the assignment to the biozone Morozovella velascoensis (P 5) in the uppermost Paleocene as well. Both nannoplankton and planktonic foraminifera are consistent with a period of global warming in the latest Paleocene just below the PETM. Nannoplankton assemblages are relatively rich in discoasters which suggests that they were deposited in a warm oligotrophic environment. Planktonic foraminifera indicate oligotrophic habitats, warm surface water and a well stratified water column with stable thermocline. Predominance of planktonic foraminiferal species and the presence of the deep-sea ostracod species Cytherella sp suggest sedimentation in deeper opensea environments. A peculiar sphaerical benthic foraminifer Aberisphaera sp., which has been found in the NE Himalayas and in the Nanos section, possibly indicates a connection between these two geographically remote areas