Design of continuous ion exchange process for the wastewater treatment

A generic design procedure for the continuous ion exchange process is proposed. The procedure is based on the optimized arrangement of parallel batch columns. The continuity of the process is achieved by proper shifting of the inlet conditions. The method for the optimization of the process variables is presented.The concept is demonstrated on the example of ammonia removal from wastewaters. Two flowsheet schemes are considered utilizing fresh or recycled regenerating agent.The superiority of the optimized process over the periodic operation is demonstrated.     

Optimal design of a Kirchhoff-Love plate of variable thickness by application of the minimum principle

Structural and Multidisciplinary Optimization - An approximate thickness optimization of a rectangular Kirchhoff-Love plate with variable stiffness under uniform load is performed in this paper....     

Study on Separation of Lanthanum from Praseodymium Complexes with IMDA by Gel and Macroporous Anion Exchangers

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Technical and financial aspects of renewable energy applications in Poland

The technical and financial aspects of renewable energy applications in Poland are analysed. The main characteristic statistics of the Polish energy situation are presented. The emphasis is put on the technical and financial problems of when and how different renewable sources can be useful and efficient in Polish conditions. The important issue is to identify the energy sectors where the implementation of renewable energy can give good results, improving in an evident way, energy efficiency and the environment. In the paper, examples of renewable energy applications supported by national environmental funds are described.     

Carbon nanofibers produced from modified electrospun PAN/hydroxyapatite precursors as scaffolds for bone tissue engineering

In the current study we have proposed a method to obtain a carbon/HAp bioactive nanofibrous scaffold. The modified carbon nanofibrous nonwoven' fabrics were obtained by the use of electrospinning and subsequent stabilization and carbonization processes. The modified with HAp powder nanofibrous PAN nonwovens were thermally stabilized using a multi-stage process in the temperature ranging from 100 °C to 300 °C in an oxidative environment and then carbonized at 1000 °C in argon atmosphere. The changes of properties of composite precursor membranes taking place during stabilization and carbonization processes were investigated using the methods of: DSC, TGA, FTIR, SEM, EDX, WAXD and mechanical tests. Bioactivity was determined by assessing the formation of crystalline apatite on the surface of membranes upon immersion in Simulated Body Fluid (SBF). The FTIR, SEM and WAXD investigation clearly prove that hydroxyapatite added to the electrospinning solution was present also in composites nanofibrous nonwovens after stabilization and carbonization process. It was found that due to HAp addition: the significant decrease of fibers average diameter occurs and that the average pore size for modified membranes is smaller than for the unmodified one. On the other hand it was shown that the ceramic additive protects fibers from mass reduction during the stabilization treatment. Finally a drastic increase of mineralization activity of nCF/HAp scaffolds as compared to their nCF counterparts has been proved.     

New melamine‐formaldehyde‐ketone polymers: I. Synthesis of reactive solvents of melamine from selected ketones

Reactive solvents of melamine were prepared by reacting ketones with an excess of formaldehyde in the presence of triethylamine catalyst. The ketones used were cyclohexanone, cyclopentanone, acetophenone, benzoylacetone, biacetyl, or ethyl‐methyl ketone. The structures of the resulting reactive solvents were studied by ¹H‐NMR. The best solubility of melamine was observed for the solvent derived from ethyl‐methyl ketone. Preliminary attempts at curing the melamine solutions yielded melamine‐formaldehyde‐ketone polymers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95:1319–1332, 2005     

Hysteresis effect on traps of Si3N4 sensing membranes for pH difference sensitivity

The mechanism of different pH sensitivities on single and stacked layer silicon nitride (Si₃N₄)-electrolyte insulator semiconductor (EIS) structures was investigated for the application of an inorganic ion sensitive field effect transistor (ISFET) and reference field effect transistor (REFET) pair. The capacitance-voltage (C-V) hysteresis effect of the EIS structures was measured. In addition, pH sensitivity was evaluated with different sweep directions and ranges of the substrate bias. Based on the hysteresis results, a pH-dependent trapping effect was found to decrease the pH sensitivity on a single Si₃N₄ sensing membrane EIS structure.