PALLADIUM CATALYSTS IN HYDROGENATION REACTIONS

This paper is a review, based on the author's own papers dealing with palladium catalysts and with their applications in hydrogenation reactions. The determination of distribution of the active component, activity of palladium supported catalyst and the electrochemical methods for their investigation are described. Results of kinetic hydrogenation studies of selected olefins, unsaturated alcohols, acids, esters, ethers, dienes and alkins in the liquid phase are presented. Acid properties of hydrogen activated by palladium are discussed.     

Prognosis of the development of artificial kidneys based upon patent literature

This paper offers a fundamental methodological approach to the classifying and sorting of information oriented to the future development of renal function replacement as disclosed in patent specifications. Arranged information items are subjected to analyses and generalizations in sequential small steps down to the final prognostic consideration. Laborious and time-consuming as the process of evaluation may be, such analyses can bring very valuable studies covering the development of the field under consideration. The achieved study comes very close to the outline of future development of means for renal function replacement, as set forth by one of the world's best specialists in the field of failing kidney replacement, a pioneer in this branch and designer of the first successful artificial kidney J.W. Kolff. In an historical review the sequence of steps of patent literature evaluation follows the development of renal function replacement means as described by Hoeltzenbein.     

Self-assembly of POSS-containing block copolymers: Fixing the hierarchical structure in networks

A series of P(MMA-co-GMA)-b-PMAPOSS block copolymers (BCPs) were synthesized by ATRP. The BCPs contain POSS (polyhedral oligomeric silsesquioxane) as a pendant unit on a particular polymer block chain. In selective solvents, the BCPs self-assemble to form ordered micellar-like structures. Spherical, cylindrical or vesicle-like morphologies were produced by tuning the BCP and mixed solvent compositions. Crosslinking of the BCP by the reaction of the glycidyl groups in the P(MMA-co-GMA) block of the micelle shell (GMA = glycidyl methacrylate) with a diamine results in a long-range structure ordering. The hexagonally packed cylindrical arrangement of the BCP networks was revealed by SAXS and TEM. The hierarchical, ordered structure of the POSS-containing hybrids was fixed by crosslinking. In addition, transient physical gels were prepared from triblock copolymers with outer MAPOSS blocks, and their rheological behavior was investigated.     

The Influence of Thermal Expansion and Mass Loss on the Young’s Modulus of Ceramics During Firing

During the heating stage of the firing of a ceramic material, the mass \(m\) , length \(l\) , and diameter \(d\) of the sample alter their values depending on the temperature \(t\) . Young’s modulus \(E(f,m,l,d)\) measured by a sonic resonance method is also a function of the resonance frequency \(f\) . Therefore, three thermal analyses (TGA, TDA, modulated force TMA) must be performed to obtain correct values of Young’s modulus. The calculation of Young’s modulus can be simplified if TGA and/or TDA are omitted. This necessarily leads to partly incorrect results. If TGA is not performed, we have \(E[f(t),m_0 ,l(t),d(t)]\) and the relative difference \((\{E[f(t),m(t),l(t),d(t)]-E[f(t),m_0 ,l(t),d(t)]\}/E[f(t),m(t),l(t),d(t)])\) reaches 7 % for \(t> 650\,^\circ \text{ C}\) and less than 2 % for \(t< 500\,^\circ \text{ C}\) . If TDA is not performed, we have \(E[f(t),m(t),l_0 ,d_0 ]\) and the relative difference ( \(\{E[f(t),m(t),l(t),d(t)]-E[f(t),m(t),l_0 ,d_0 ]\}/E[f(t),m(t),l(t),d(t)])\) is less than 0.6 % for \(t < 1000\,^\circ \text{ C}\) . For the simplest case, we have \(E[f(t),m_0 ,l_0 ,d_0 ]\) and the relative difference ( \(\{E[f(t),m(t),l(t),d(t)]-E[f(t),m_0 ,l_0 ,d_0 ]\}/E[f(t),m(t),l(t),d(t)])\) is 7.5 % for \(t > 600\,^\circ \text{ C}\) and less than 2 % for \(t<500\,^\circ \text{ C}\) .     

Microstructure and mechanical properties of UFG medium carbon steel processed by HPT at increased temperature

Using the high pressure torsion (HPT) deformation method the medium carbon steel (AISI 1045) was the experimental material used to conduct the deformation process. The torsion deformation experiment was performed at increased temperature of 400 °C. The influence of deformation processing parameters, resolved shear strain γ (number of turns N = 1–6) and applied pressure p (constant pressure of 7 GPa), was evaluated by microstructure analysis and mechanical properties. The strength behaviour was assessed by microhardness measurements across the disc to detect the positional hardening, by tensile tests and in situ measured torque. In situ measurement of torque during deformation allows characterizing the changes in mechanical properties due to the large shear deformation developed across the disc. To obtain absolute values of strength the ultimate tensile strength was measured in radial direction with respect to the deformed sample. From each deformed disc two sub-sized tensile test specimens with gauge length of 2.5 mm were machined. The tensile strength in samples increased markedly with the number of turns. The hardness measured at disc edge gradually increases as straining increases until it saturates after 2–3 turns. However, the hardness values at edge were different from those measured in disc centre and for applied straining no saturation was reached across the disc. The SEM and TEM investigations were carried out to analyze the fine microstructure evolution regarding the strain introduced. To follow the difference in strain distribution across the deformed disc the microstructure analysis was performed at edge and central site of the disc in order to evaluate the effect of the strain distribution. TEM investigation confirmed the increasing misorientation even in very small grains, the fragmentation and dissolution of the cementite lamellae, (diffuse cementite/ferrite boundaries), the alignment of the fragments to the shear plane with increasing deformation. Indistinct deformation of ferrite and preserved cementite lamellae morphology were found at the centre of the disc.