Estimation of the diffusion coefficient from sorption measurements

In this paper a procedure for the estimation of the diffusion coefficient for a sorption process from the measurements of the adsorbed amount is proposed. The experiments from which the data have been obtained are described and the numerical results are discussed.     

Experimental investigation of the effect of injection of products of decomposition of pastelike coolant on the electrical conductivity of the flow of pulsed MHD generator

A large-scale model of the channel of a pulsed MHD generator is investigated in an applied electric field. It is demonstrated that the flow of plasma under conditions of wall protection by way of injecting the products of decomposition of a pastelike coolant is realized with a clearly pronounced core and thin boundary layers. In the case of injection on the insulating walls alone, the integral electrical conductivity of flow remains almost constant in a wide range of injection intensity up to the value of 4%. The injection into the electrode boundary layer causes a considerable reduction of its electrical conductivity     

Experimental investigation of a large-scale paste-cooled MHD channel

The results are given of experimental investigations of the continuous-electrode channel of a pulsed Faraday MHD generator of the Pamir type [1–4]. In the channel, the most heat-stressed inlet section is paste-cooled. The channel may be readily disassembled, which enables one to exchange the structures of both electrode and insulating walls during the runs with a view to investigating the effect of the structure on the power performance. The runs are performed with a solid-fuel plasma generator (with the pressure and temperature in the combustor of ~4.5 MPa and 3750 K) in different modes, namely, with applied electric field in order to determine the electrical conductivity of the working medium and the effect of the injection of decomposition products on the electrical conductivity, and in modes with induced field (independent excitation and self-excitation with reaching the extreme operating mode such as short-circuiting) in order to compare the power performance of the channel for different techniques of injection and removal of the cooling agent decomposition products. A sublimating pastelike cooling agent on the basis of ammonium oxalate is used. It is demonstrated that the injection of the products of decomposition of cooling agent on the insulating walls has no effect on the power performance of the channel. The experiments have revealed a high resistance and desired insulating properties of paste-cooled structures under conditions of repeated operation, as well as the agreement in the power performance between paste-cooled and uncooled channels. The obtained results point to the possibility of developing paste-cooled channels of pulsed MHD generators.     

Characterization of ALBA Family Expression and Localization in Arabidopsis thaliana Generative Organs

ALBA DNA/RNA-binding proteins form an ancient family, which in eukaryotes diversified into two Rpp25-like and Rpp20-like subfamilies. In most studied model organisms, their function remains unclear, but they are usually associated with RNA metabolism, mRNA translatability and stress response. In plants, the enriched number of ALBA family members remains poorly understood. Here, we studied ALBA dynamics during reproductive development in Arabidopsis at the levels of gene expression and protein localization, both under standard conditions and following heat stress. In generative tissues, ALBA proteins showed the strongest signal in mature pollen where they localized predominantly in cytoplasmic foci, particularly in regions surrounding the vegetative nucleus and sperm cells. Finally, we demonstrated the involvement of two Rpp25-like subfamily members ALBA4 and ALBA6 in RNA metabolism in mature pollen supported by their co-localization with poly(A)-binding protein 3 (PABP3). Collectively, we demonstrated the engagement of ALBA proteins in male reproductive development and the heat stress response, highlighting the involvement of ALBA4 and ALBA6 in RNA metabolism, storage and/or translational control in pollen upon heat stress. Such dynamic re-localization of ALBA proteins in a controlled, developmentally and environmentally regulated manner, likely reflects not only their redundancy but also their possible functional diversification in plants.     

Synthesis of poly(sebacic anhydride): effect of various catalysts on structure and thermal properties

Combining different polymeric systems can be a useful tool to create new networks with different characteristics with respect to the starting materials. In this work, hydrogels composed of gellan gum (GG) and polyethylene glycol dimethacrylate (PEG-DMA) were realized to overcome the fragility problems of physical gels of GG, which limit their biological application as scaffold for tissue engineering. The two polymeric systems were combined using different synthetic approaches, with particular attention to the double network strategy (DN). The influence of several parameters on the mechanical properties, such as the time of diffusion and the molecular weight of PEG-DMA, were evaluated by rheological studies and compressive texture analyses. The hydrogels were also investigated for their ability to swell and release model molecules with different sterical hindrances, such as vitamin B12 and myoglobin. Finally, to estimate the biological safety of the hydrogels, their effect on mitochondrial function of human fibroblasts was investigated.     

Basic study of ceramic lithium strontium borates as thermal neutron scintillators

A special group of luminescence materials are scintillators for thermal neutron detection. Due to the properties of neutrons (contrary to e.g. electrons or gamma photons), a different approach has to be utilized—the high content of atoms with the sufficient absorption cross-section toward neutrons and lower material density are needed. This work pursues a basic study of LiSrBO₃ and LiSr₄(BO₃)₃ doped with cerium or europium—materials promising as thermal neutron scintillators. These borates exhibit promising properties such as the high content of lithium and boron, suitable density, and proper environment for luminescent ions. Radioluminescence of these ceramic borates doped with cerium and europium was examined and promising samples were further characterized by photoluminescence spectroscopy and radioluminescence and photoluminescence kinetics measurement. The radioluminescence study of these borates is published for the first time. Cerium-doped borates, in particular, exhibit a very promising response to an X-ray excitation.     

New path in the thermal cracking of triacylglycerols (canola and soybean oil)

Triacylglycerols (TGs) are naturally occurring oils abundant in many crops. A series of batch uncatalyzed thermal decomposition experiments were performed using canola and soybean oils to explore pathways of TG cracking. A detailed gas chromatographic protocol based on mass spectrometric identification and flame ionization quantification was applied to the organic liquid product generated upon cracking. Reaction conditions were identified that resulted in a novel organic liquid product (OLP) composition compared to previously reported work. Under these conditions (temperatures within a 420-440 °C range) a new route for TG thermolysis was discovered in which cracking reactions of original TG-bound fatty acids were nearly complete and led to the formation of 15-25 wt.% C₂-C₁₀ linear saturated monocarboxylic acids and ca. 30% linear alkanes. Less than 2 wt.% C₁₆-C₁₈ fatty acids which were originally present in the feedstocks as glycerol triesters were found in the OLP. These reactions appear to be kinetically controlled due to abundant hydrogen formation. This route provides a significant enrichment of low-MW compounds in the OLP (65-70 wt.% being <C₁₁) and thus may be considered as a new option for the production of replacement products for petroleum-based fuels and chemicals.     

Subcritical (hot/liquid) water dechlorination of PCBs (Aroclor 1254) with metal additives and in waste paint

No disposal option exists for "mixed wastes" such as paint scrapings that are co-contaminated with polychlorinated biphenyls (PCBs) and radioactive metals. Either removal or destruction of the PCBs is required prior to disposal. Comparison of subcritical water dechlorination (350 degrees C, 1 h) of Aroclor 1254 in paint scrapings (180 ppm) and of standard Aroclor 1254 showed significantly enhanced dechlorination in the presence of paint. While no significant degradation was observed for standard Aroclor (no paint), the dechlorination of PCBs in paint was 99, 99, and 80% for the hepta-, hexa-, and pentachlorinated congeners, respectively, indicating that metals in the paint enhanced the dechlorination reactions. Adding metals to the standard Aroclor (no paint) reactions enhanced PCB dechlorination in subcritical water in descending order of activity: Pb approximately = Cu > Al > Zn > Fe. In the presence of both zerovalent and divalent lead and zerovalent copper in subcritical water (350 degrees C, 1 h), 99% of the Aroclor 1254 mixture (tetra- to heptachlorinated biphenyls) was dechlorinated. High dechlorination (ca. 95%) was also achieved with zerovalent aluminum. In contrast to other metals, lead retained its degradation ability at a lower temperature of 250 degrees C after 18 h. The high degradation efficiency achieved using metal additives in water at reasonable temperatures and pressures demonstrates the potential for subcritical water dechlorination of PCBs in paint scrapings and, potentially, in other solid and liquid wastes.