We have investigated the transesterification of rapeseed and waste sunflower oils with methanol in the presence of catalyst. The effect of the temperature on the reaction rates was studied at a constant molar ratio alcohol:triacylglycerols and for a constant catalyst concentration. Size-exclusion chromatography and 1H NMR spectroscopy were used to quantitatively monitor the transesterification reaction. The mass-transfer coefficients of the triacylglycerols depended on the type of oil and temperature. Activation energies were calculated and the optimum methanol recycle ratio was established.
COBISS.SI-ID: 33677317
In order to find out possible correlations between the activities carried out in buildings, the characteristics of buildings and number of fires, we used a random sample which included 134 buildings as industrial objects, hotels, restaurants, warehouses and shopping malls. Our study shows that the floor area of buildings has low impact on the incidence of fires. After analysing the sample of buildings by using multivariate analysis we proved a correlation between the number of fires, floor area of objects, work operation period (per day) and the number of employees in objects.
COBISS.SI-ID: 33808645
The purpose of this work was to prepare nanocomposites by mixing multi-walled carbon nanotubes with nitrile and hydrogenated nitrile elastomers. Utilization of two microscopy techniques and X-ray scattering techniques for advanced morphology observation is reported. Principal results were increases in hardness, elastic modulus, tensile strength, elongation at break, cross-link density, density, and tear strength. Conclusion was that multi-walled carbon nanotubes improved the performance of nitrile and hydrogenated nitrile rubber nanocomposites.
COBISS.SI-ID: 34274821
The biosorption of lead ions from aqueous solution on a self-immobilized Rhizopus nigricans biomass has been studied. Experiments were performed in a laboratory scale packed bed column at different liquid flow rates and biosorbent bed heights. Recorded experimental breakthrough curves were compared to those predicted by a mathematical model, which was developed to simulate a packed bed biosorption process. In the range of examined experimental conditions, the biomass characteristics such as pellet porosity and biosorption capacity substantially affected the predicted response curve.
COBISS.SI-ID: 34326021
In order to determine the effect of different exposures to light on the growth of microalgae Chlorella vulgaris, a series of tests was carried out. Light duration within a day cycle was varied and algae concentration was being monitored. The utilized growth medium was ten-times diluted low-nitrogen medium.
COBISS.SI-ID: 34476805