COMPUTATIONAL CHALLENGES IN CONDENSED MATTER APPLICATIONS
Our paper focuses on computer simulation of the transport processes in nanoporous systems. This systems are considerably more complex than diffusion in homogeneous phases or in macroporous systems. The pathways in nanoporous systems are, by design, similar to the dimensions of the diffusing species. Adsorbate-adsorbate and adsorbate-adsorbent interactions are enhanced. The energetic of transport differs from molecular theory often to reflect activated processes with apparent activation energies. Entropic factors also play an increasing role in the transport. Dissolution as well as diffusion between chains must be considered in polymers. Adsorbent flexibility is a factor of varying significance in both inorganic and organic solids. Simple extensions of homogeneous theories are inadequate, as these specific interactions need to be included. This paper deals with an empirical algorithm, which analyses the physical parameters over the copolymer network properties as a relation between the molecular ratios of copolymer sequences. We also present the performance of the proposed method in relation to the fitness function and the local twist.
Amphyphylic copolymers as water delivery systems
Abstract Various polydimethylsiloxane-co-poly(methacrylic acid) networks were prepared by initiating the radical polymerization of methacrylic acid in presence of azoester containing polydimethylsiloxane (PDMS) and of ethyleneglicole dimethacrilate as crosslinking agent. The chemical structure and the thermal behavior of these hydrophobic–hydrophilic gels were established by IR spectroscopy, scanning electron microscopy and differential scanning calorimetry. Also, the water delivery tests were performed and the possibility to use amphyphilic copolymers as systems to mention humidity in soil is discussed. According to the experimental results a mechanism of water delivery were proposed where the hydrophilic (poly(methacrylic acid)) and hydrophobic (PDMS) sequences have different rolls in this mechanism.
Palaeocarpinus (Extinct Betulaceae) from Northwestern China: New Evidence for Paleocene Floristic Continuity between Asia, North America, and Europe
Spiny-bracted fruits of Palaeocarpinus Crane, a genus of Betulaceae previously known only from Europe and North America, have been discovered in the Paleocene of Altai, northwestern China. The fruits are found in association with abundant Corylus-like foliage and staminate catkins containing Corylus-like pollen. Because of problems distinguishing leaves of Corylus from those of extinct betulaceous genera, we place these leaves in the genus Corylites Gardner ex Seward & Holttum. The fruits, staminate catkins, pollen, and leaves from Altai were probably all produced by a single species. Palaeocarpinus orientalis is nearly identical in its morphology to Palaeocarpinus joffrensis from the Paleocene of North America except in the more rounded primary bracts of the associated staminate catkins. The species is less similar to Palaeocarpinus laciniata from the Paleocene of southern England.