University of Maribor

About: University of Maribor is a education organization based out in Maribor, Slovenia. It is known for research contribution in the topics: Population & KEKB. The organization has 3987 authors who have published 13077 publications receiving 258339 citations. The organization is also known as: Univerza v Mariboru.

Dynamic compressive loading of expanded perlite/aluminum syntactic foam

Abstract: This paper addresses the analysis of expanded perlite/aluminum (EP/A356) syntactic foams under dynamic compressive loading conditions. Experimental and numerical analysis are conducted in order to determine compressive stress–strain response, effective material properties and deformation mechanisms. Foam samples are manufactured by combining A356 aluminum alloy with expanded perlite particles that introduce 60–65% porosity. Under compressive loading these pores gradually collapse resulting in an approximately constant macroscopic stress level of the syntactic foam. Testing at different compression velocities shows that the expanded perlite particles increase the compression resistance at higher strain rates. The effective material properties of the syntactic foam increase both with density and loading velocity. Infrared (IR) thermal imaging and finite element analysis allowed the independent identification of the dominant deformation mechanism: single struts that are parallel to the loading direction buckle and trigger the formation of multiple collapse bands that are approximately perpendicular to the loading direction.

Frequency-difference-dependent stochastic resonance in neural systems.

Abstract: Biological neurons receive multiple noisy oscillatory signals, and their dynamical response to the superposition of these signals is of fundamental importance for information processing in the brain. Here we study the response of neural systems to the weak envelope modulation signal, which is superimposed by two periodic signals with different frequencies. We show that stochastic resonance occurs at the beat frequency in neural systems at the single-neuron as well as the population level. The performance of this frequency-difference-dependent stochastic resonance is influenced by both the beat frequency and the two forcing frequencies. Compared to a single neuron, a population of neurons is more efficient in detecting the information carried by the weak envelope modulation signal at the beat frequency. Furthermore, an appropriate fine-tuning of the excitation-inhibition balance can further optimize the response of a neural ensemble to the superimposed signal. Our results thus introduce and provide insights into the generation and modulation mechanism of the frequency-difference-dependent stochastic resonance in neural systems.

Hydrothermal Synthesis of Ba‐Hexaferrite Nanoparticles

Abstract: Barium hexaferrite BaFe12O19 nanoparticles with a single-domain size were synthesized using a controlled hydrothermal process involving the LaMer–Dinger principle and the Ostwald ripening mechanism. Nanocrystalline particles of BaFe12O19 were obtained when the molar ratio of the precursor composition Ba(OH)2·8H2O/γ-Fe2O3 was 0.3 and the concentration of the suspension was about 1 wt%. The as-synthesized crystalline BaFe12O19 platelets approximately 50 nm in length and 5 nm in thickness exhibited a saturation magnetization of 40 Am2/kg.

PolyHIPE Supports in Batch and Flow-Through Suzuki Cross-Coupling Reactions

Abstract: As part of ongoing research efforts to discover alternative support materials to polymer beads for use in polymer-supported synthesis, particularly under flow-through conditions, this work involves the synthesis of PolyHIPE (High Internal Phase Emulsion) polymer monoliths. PolyHIPEs containing high loadings of chloromethyl groups were efficiently prepared by the direct copolymerization of 4-vinylbenzyl chloride and divinylbenzene monomers. The ‘Merrifield' PolyHIPE proved to be an excellent support for batch and flow-through Suzuki cross-coupling reactions. A remarkably high yield of pure biaryl product was obtained using the PolyHIPE support in cubic form and utilizing an electron-rich boronic acid. In comparison to polymer beads, this material was found to be a much more efficient support in both batch and continuous flow modes. PolyHIPE converted a greater amount of chloromethyl groups into biaryl product under identical reaction conditions. It is suggested that the absence of channelling with PolyHIPE...