Kinetic studies of esterification reaction of maleic anhydride with butan-1-ol, 2-methylpropan-1-ol and butan-2-ol were carried out in a semibatch reactor, in the presence of four acidic catalysts: sulfuric acid, phosphotungstic acid, ion exchange resin Dowex 50WX8 and tetrabutyl zirconate. Phosphotungstic acid proved to be the most active catalyst. The temperature range was 383–413 K, the initial molar ratio of alcohol to acid ranged 2.2-5:1. The kinetic parameters were given. The kinetics appeared to be that of the second order with respect both to the acid and to the alcohol. The reaction carried out in the presence of tetrabutyl zirconate was very slow and depended only on acid concentration. The effect of temperature on the reaction rate follows the Arrhenius equation well.

The aim of the research presented in this paper was to determine the effect of vessel scale on gas hold- up in gas-liquid systems. The agitated vessel with internal diameters of T = 0:288 m and T = 0:634 m was filled with a liquid up to the height H = T. For the purpose of measurements, two high-speed impellers were used: Rushton turbine impeller (RT) or A 315 impeller.Within the study, the following parameters were altered: superficial gas velocity, impeller speed, impeller type and concentration of aqueous sucrose solution. In addition, influence of the vessel scale on gas hold-up value was analysed. Experimental results were mathematically described. Equations (5)–(7) do not have equivalents in the literature.

Thermoelectric generators using the Seebeck effect to generate electricity are increasingly used in various areas of human activity, especially in cases where a cheap high-temperature heat source is available. Despite many advantages, TEG generators have one major disadvantage: very low efficiency of heat conversion into electrical power which strongly depends on the applied load resistance. There is a maximum of generated power between the short and the open circuit in which it is zero. That is why optimization of TEG modules is particularly important. In this paper a method of maximization of generated power in a single TEG module is presented for two cases. The first case concerns a problem with fixed heat flux flow into the hot side of the module whereas the second one concerns a problem with fixed heat transfer parameters in hot heat exchanger i.e. supply gas temperature and heat transfer coefficient. A number of optimization results performed for various values of these parameters are presented and discussed.

The study aimed to produce nano- and microfibrous materials from polyurethane (ChronoFlex®C75A/ C75D in 1,1,1,3,3,3–hexafluoro–2–propanol) by solution blow spinning. Experiments were carried out in order to determine the impact of solution blow spinning parameters on fibre diameter and quality of produced materials. The following properties of produced fibre scaffolds were investigated: fibre size, porosity and pore size, wettability, and mechanical properties. The results confirmed that produced nano- and microfibrous materials could be potentially used as scaffolds in three-dimensional cell and tissue cultures.

In this study, we performed the qualitative analysis of exoproteins during granule formation in the pres- ence or in the absence of cations. The staining of thin granule cryosections showed that nucleic acids, proteins, polysaccharides and calcium cations were the dominant components of the granules. Proteins are the structural components associated with calcium ions. We determined changes in the proteomic profile and tightly bound extracellular polymeric substances (EPS) of the slime. The exopolymeric matrix containing the proteins was extracted using the Dowex resin method. Proteomic profile was analysed by SDS-PAGE method (sodium dodecyl sulphate polyacrylamide gel electrophoresis) using Coomassie blue staining in the samples of the aerobic granule matrix formed in the presence of multivalent cations and compared with that of the aerobic granules cultivated without cations. The results indicate that the granule matrix is predominantly composed of large and complex proteins that are tightly bound within the granular structure. The tightly bound extracellular polymeric substances (TB-EPS) may play a role in improved mechanical stability of aerobic granules. In the supernatant fraction of the sludge, only a small amount of free proteins in the medium molecular mass range was detected. The protein with high molecular mass ( 116 kDa) produced in the reactors with added Ca2+. Ca2+ had a considerable regulatory influence on production of extracellular proteins during aerobic granulation.