Organogels as a Tool to Generate Anion:Cation Selective Membranes

Porous membranes consisting of poly[2-ethyl-hexyl methacrylate-co-2-diethylaminoethyl methacrylate-cross-1,4-butane diol dimethacrylate] have been prepared by means of the “gel template leaching” strategy. Well-defined cylindrical pores with diameters of 6–15 nm have been obtained on applying N-(2-desoxy-sorbityl)-3′, 4′,5′-tris(dodecyloxy)benzamide as organogelator. Chemical modification of the pores' inner walls with methyl iodide to introduce tetra alkyl ammonium surface groups yielded functional membranes with cationic charged pores. The membranes exhibited anion:cation selectivities depending on the electrolyte concentration. At an ion strength of 1 mM the anion:cation selectivity exceeded values of 100.     

HIGH TEMPERATURE DRYING OF WOOD SEMI-INDUSTRIAL KILN EXPERIMENTS

We briefly introduce the main results obtained in our laboratory about high temperature drying kinetic of softwood and hardwood. We point out during drying the acceleration effect of pressure gradient in vapour phase which develops in the wood.

Then we give the main experimental results carried out on a small industrial kiln which can dry wood boards with moist air and superheated steam at high temperature till 180°C and velocity above to 6 m/s. The drying process is completely automated. Tested species are : beech, poplar, fir and maritime pine.

We show that the drying kinetics are almost the same using the industrial kiln or the wind tunnel and we define for different board thicknesses, temperatures and velocities the optimal sequences of the process. The influence on the quality of the pretreatment, the various drying periods and the post-steaming is of importance.     

Comparing Al-SBA-15 Support and Pt/Al-SBA-15 Catalyst: Changes in Al Speciation and Acidic Properties Induced by the Introduction of Pt via Aqueous Medium

Differences between the acidic properties of silicoaluminic Pt-containing catalysts and those assessed on their parent supports have been reported in the literature and attributed to the presence of the metal nanoparticles and to their influence on the acid sites. It is shown here that for mesoporous materials containing various types of Al species, an alternative explanation can be proposed. ²⁷Al NMR spectroscopy, FTIR of adsorbed CO and probe catalytic tests suggest the redistribution of aluminium atoms upon contact of the parent support with the aqueous solution containing the Pt precursor. Upon contact with water and thermal treatment, strong and mild Brønsted sites (Si–O(H)–Al) transform into strong Lewis sites (isolated tetracoordinated Al atoms). As a consequence, it may not be straightforward to deduce the acidic properties of metal-containing catalysts supported on Al-containing mesoporous materials from those of the bare support, because the surface species may differ significantly.     

The three Rs of river ecosystem resilience: Resources,recruitment, and refugia

Resilience in river ecosystems requires that organisms must persist in the face of highly dynamic hydrological and geomorphological variations. Disturbance events such as floods and droughts are postulated to shape life history traits that support resilience, but river management and conservation would benefit from greater understanding of the emergent effects in communities of river organisms. We unify current knowledge of taxonomic‐, phylogenetic‐, and trait‐based aspects of river communities that might aid the identification and quantification of resilience mechanisms. Temporal variations in river productivity, physical connectivity, and environmental heterogeneity resulting from floods and droughts are highlighted as key characteristics that promote resilience in these dynamic ecosystems. Three community‐wide mechanisms that underlie resilience are (a) partitioning (competition/facilitation) of dynamically varying resources, (b) dispersal, recolonization, and recruitment promoted by connectivity, and (c) functional redundancy in communities promoted by resource heterogeneity and refugia. Along with taxonomic and phylogenetic identity, biological traits related to feeding specialization, dispersal ability, and habitat specialization mediate organism responses to disturbance. Measures of these factors might also enable assessment of the relative contributions of different mechanisms to community resilience. Interactions between abiotic drivers and biotic aspects of resource use, dispersal, and persistence have clear implications for river conservation and management. To support these management needs, we propose a set of taxonomic, phylogenetic, and life‐history trait metrics that might be used to measure resilience mechanisms. By identifying such indicators, our proposed framework can enable targeted management strategies to adapt river ecosystems to global change.     

Impact of the surface characteristics of rainwater tank material on biofilm development

In order to determine the impact of rainwater construction material on the development of a biofilm, three materials were tested: concrete, clay, and PVC. The biofilm attachment was initially more effective on clay coupons, but, after a period of three days, concrete coupons produced a greater quantity of biofilm than clay and PVC, in that order. The heterotrophic plate count in the rainwater indicated that this quantity tended to first increase following a rainfall, and then decrease. The new materials seemed to attach themselves to the existing biofilm on the wall and/or sediment in the form of small particles. The presence of fecal coliforms in the biofilm coupons was noted after major rainfall events, and this was correlated with the increase in fecal coliforms in the water. This study concluded that the most favorable support for biofilm development is concrete, clay, and PVC, in that order.     

Factors Affecting Catalase Activity in Staphylococcus aureus MF-31

Selected conditions were examined for their possible roles in the regulation of catalase activity in Staphylococcus aureus MF-31. The addition of the heme precursor 5-aminolevulinic acid resulted in increased catalase activity whereas the addition of exogenous hydrogen peroxide did not. Catalase activity decreased when S. aureus MF-31 cells were grown in media containing glucose. Cells grown in media with succinate or citrate substituted for glucose exhibited increased catalase activity. Cells grown in tryptic soy broth (0.5% NaCl) supplemented with NaCl showed increased catalase activity at salt concentrations up to 3%.     

ENERGY CONSERVATION IN DRYING OF FRUITS IN TUNNEL DEHYDRATORS

This study reports the energy use and thermal losses associated with tunnel dehydrators and discusses methods of increasing energy efficiency. These dehydrators can operate with an efficiency of water removal greater than 50%. It is shown that energy conservation techniques such as minimizing air leakage, increasing air recirculation, utilizing a furnace heat shield to prevent heat losses, and maximizing input can result in significant energy savings.     

Reproducibility of Microbiological Counts on Frozen Cod: A Collaborative Study

Reproducibility of aerobic plate count (APC), coliform and fecal coliform counts in frozen cod was examined by 14 laboratories (3 government, 4 university and 7 industry) using primarily FDA recommended procedures. In order to assure homogeneity of samples, the fish was comminuted and thoroughly mixed. The 35°C and the “room temperature” (26°C) APC on Sample A (a good quality product) were 1.3 × 10⁵/g and 2.6 × 10⁵/g, respectively, and for Sample B (a questionable quality product) the counts were 2.9 × 10⁵/g and 6.4 × 10⁵/g, respectively. Standard deviations among counts (log₁₀ values) were 0.26 and 0.32 for the 35°C counts and 0.24 and 0.40 for the 26°C counts of Sample A and B, respectively. The std. dev. were reduced to 0.19, 0.22, 0.17 and 0.25, respectively, when counts that did not show significant overlap (based on Dur can's New Multiple Range Test) were excluded from the calculations. Coliform counts on Sample A (not inoculated) ranged from <30 to 4.6 × 10⁵/100g. Coliform and fecal coliform counts for Sample B (inoculated at estimated level of 1 × 10⁴/100g) were 5.8 × 10³/100g and 5.5 × 10³/100g, with a std. dev. of 0.43 and (.37, respectively. The std. dev. for the coliform counts was reduced to 0.30 when counts from one laboratory were excluded, based on Duncan's New Multiple Range Test.