Unsteady motion of the impeller is one of the several methods to improve mixing in unbaffled vessel. It is very important in pharmaceutical industry, crystallization processes or some chemical reaction with catalyst where baffles are not recommended. The literature data shows that unsteady mixing cause generation of axial flow for radial impellers (Rushton turbine). The purpose of this study was to investigate axial force for axial impellers like A315, HE-3 and SC-3. Moreover, the momentum number, flow number and pumping efficiency were analysed. Results shows that axial force for unsteady mixing is higher in comparison to steady-state mixing. Also, the comparison of axial force between impellers shows that blades influence momentum number and flow number. Impellers with larger blade surface generate stronger axial force. The obtained results reveal that unsteady mixing with axial impellers could be apply for solid-liquid mixing as suitable alternative to steady-state mixing.

The paper presents the effects of sodium chloride on the rheological properties of aqueous solutions of cocamidopropyl betaine (CAPB) and sodium dodecylbenzene sulfonate (SDBS) mixtures. Studies were carried out in the CAPB/SDBS molar ratio range of 0.95 to 3.5, at sodium chloride concentrations varying from 0.03 M to 0.75 M. Continuous and oscillatory flow measurements showed that the impact of sodium chloride concentration on shear viscosity and relaxation time was closely linked to the CAPB/SDBS molar ratio. The maximum shear viscosity and the longest Maxwell relaxation time were obtained at the CAPB/SDBS molar ratio of 2. Based on CryoTEM images, it was determined that the shear viscosity and relaxation time peaks identified at a certain concentration of sodium chloride could be attributed to the transition of the entangled wormlike micellar network into branched wormlike micelles. Changes in the micellar microstructure accompanying modifications of the CAPB/SDBS molar ratio and sodium chloride concentration were accounted for on the basis of the packing parameter.

The work presents a two-step method of iron red synthesis based on waste iron(II) sulfate. The synthesis was carried out using purified waste iron sulfate from titanium dioxide production. The study investigated the influence of factors such as temperature, pressure, concentration of solutions and synthesis time on the physicochemical properties of pigments. Obtained pigments were tested by instrumental analytical methods, e.g. X-ray Diffraction or BET surface area analysis. The pigments were analyzed for color, praticles size as well as for oil number. The results of the research showed a change in the physicochemical properties of the obtained pigments depending on the conditions of synthesis. It was shown that increasing the synthesis time in most cases increased the degree of crystallization of hematite in the pigments. High specific surface area, low agglomeration of pigments or low oil absorption are directly related to the crystallinity of the pigments obtained. Laboratory pigments have been found to be different from commercial pigments. The difference in properties speaks in favor of synthesized materials.

The development of efficient carbon dioxide sequestration and utilization technologies is an indispensable aspect of a wide range of measures directed at reducing the negative effects of anthropogenic emissions on the environment. One route is its capture via physical adsorption and further conversion to methane in the Sabatier reaction. The sorption process can be carried out, among others, in fixed-bed adsorptive reactors, in which the packing is made up of adsorbent and catalyst particles. Proper structuring of such a hybrid bed can contribute to increasing the efficiency of both stages of the process. Of importance in this regard is, first of all, the proper management of heat transfer. This study examines the sorption step of the operation of an adsorptive reactor for CO2 sequestration and methanation using a one-dimensional non-isothermal model of a layered fixed bed. Numerical calculations for different configurations and different volume adsorbent to catalyst ratios were carried out to determine how the hybrid structure of the bed and the atypical thermal waves it induces affect the sorption process. The results obtained prove that proper tailoring of the bed can be an excellent tool to control the temperature profiles and thus the performance of the apparatus and possibly its optimization.

Studies on the surface-active agents added during the cultivation process proved their effect on the synthesized bioproducts. The biosynthesis and accumulation of exopolysaccharide and biomass by Antarctic producer Cryptococcus laurentii AL65 were studied in submerged cultivation using different carbon sources in the culture medium added to a one-percent concentration (pentoses, hexoses and oligosaccharides). Sucrose was chosen as the most appropriate carbon source for the cell growth and extracellular polymer biosynthesis. Absorption of sucrose by a strain producer was monitored and the residual sugars were traced in the dynamics of the fermentation process. The effect of polyoxyethylene sorbitan monooleate (Tween 80) on the cell growth and the accumulation of the synthesized biopolymer were studied for the first time with the Antarctic producer. The optimal increase in the amount of accumulated exopolysaccharide was recorded at a concentration of 6% Tween 80 at 24 h from the start of fermentation. The surfactant treatment contributed to an increase in the total amount of lipids in the cell, to the increased biosynthesis of unsaturated fatty acids compared to saturated ones, and to the increased cellular synthesis of valuable metabolites such as phosphatidylinositol, phosphatidylserine and phosphatidylethanolamine. The impact of Tween 80 on intracellular and extracellular metabolites is a valuable asset in a possible scale-up of the process in industrial settings.

Polar snow and its accumulation preserve valuable information derived from the atmosphere on past climate and environmental changes in high resolution, particularly in coastal sites. A 2.5-m snow-pit was excavated from the coastal ice rise (Moore Dome) near Amundsen Sea region in February 2012. This study evaluated the isotopic and chemical compositions in the snow-pit and compared them with meteorological variables. Based on the seasonal peaks of the MSA and nssSO42– together with 18O, D, and d-excess, the snow-pit record was corresponded to accumulation during austral winter 2011 to summer 2011/2012. The annual mean accumulation rate was assumed thus to be as large as or even higher than 1.03 m w.e. yr–1 at this site. A relatively warm winter temperature in 2011 was traceable in the variations of 18O, D, and d-excess. This study emphasizes the importance of the high snow accumulation observed at this site in providing valuable information on sub-annual variations in climate and environmental changes through the study of longer ice cores.