1. Multiple twisted chiral nematic structures in cylindrical confinementMilan Ambrožič, Apparao Gudimalla, Charles Rosenblatt, Samo Kralj, 2020, izvirni znanstveni članek Opis: In this article, we theoretically and numerically study the chirality and saddle-splay elastic constant (K24)
-enabled stability of multiple twist-like nematic liquid crystal (LC) structures in cylindrical confinement. We focus on the so-called radially z-twisted (RZT) and radially twisted (RT) configurations, which simultaneously exhibit twists in different spatial directions. We express the free energies of the structures in terms of dimensionless wave vectors, which characterise the structures and play the roles of order parameters. The impact of different confinement anchoring conditions is explored. A simple Landau-type analysis provides an insight into how different model parameters influence the stability of structures. We determine conditions for which the structures are stable in chiral and also nonchiral LCs. In particular, we find that the RZT structure could exhibit macroscopic chirality inversion upon varying the relevant parameters. This phenomenon could be exploited for the measurement of K24.
Ključne besede: liquid crystals, chirality, confinement, saddle-splay elasticity, double twist deformations
Objavljeno v DKUM: 14.01.2025; Ogledov: 0; Prenosov: 3
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2. Effect of depreciation of the exchange rate on the trade balance of AlbaniaSafet Kurtović, Blerim Halili, Nehat Maxhuni, 2017, izvirni znanstveni članek Opis: The paper investigates the effect of the real effective exchange rate depreciation of the lek on the trade balance of Albania using quarterly data from 1994 to 2015. Bounds testing cointegration approach, vector error correction model (VECM), and impulse response were used for the empirical analysis. The results of the study show a long-term cointegration between the real effective exchange rate (REER) and the trade balance (TB). Specifically, the REER depreciation positively affects the trade balance of Albania in both the long and short run, indicating the weak presence of the J-curve effect. Important recommendations were derived from the results.
Ključne besede: J-curve, cointegration, elasticity, short-term effect, long-term effect
Objavljeno v DKUM: 03.05.2018; Ogledov: 1274; Prenosov: 447
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3. Estimation of demand functions for services of public railway passenger transportation : evidence from SloveniaJani Bekő, 2004, drugi znanstveni članki Opis: The paper deals with the estimation of demand functions for services of publicrailway passenger transportation in the case of Slovenia. Six demand functions were selected and separately interpreted. The aggregate values of demand elasticities reported in this paper suggest that the railway passenger demand is price and income inelastic. Coefficients of income elasticity below unity show that the services of railway passenger transportation in Slovenia can be classified among normal goods. A hypothetical increase in average real fares leads to a percentage decrease in the number of passengers traveling by rail that is smaller than the percentage increase in fares. The estimated price elasticities imply that, in the short run, there is potential for improving revenues of the railway operator by increasing average real fares.
Ključne besede: price elasticity of demand, income elasticity of demand, price policy
Objavljeno v DKUM: 02.06.2017; Ogledov: 1582; Prenosov: 247
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4. Alignment of carbon nanotubes in nematic liquid crystalsPaul van der Schoot, Vlad Popa-Nita, Samo Kralj, 2008, izvirni znanstveni članek Opis: The self-organizing properties of nematic liquid crystals can be used to aligncarbon nanotubes dispersed in them. Because the nanotubes are so much thinner than the elastic penetration length, the alignment is caused by the coupling of the unperturbed director field to the anisotropic interfacial tension of the nanotubes in the nematic host fluid. In order to relate the degree of alignment of the nanotubes to the properties of the nematic liquid crystal, we treat the two components on the same footing and combine Landau-deGennes free energies for the thermotropic ordering of the liquid crystal and for the lyotropic nematic ordering of carbon nanotubes caused by their mutually excluded volumes. The phase ordering of the binary mixture is analyzed as a function of the volume fraction of the carbon nanotubes, the strength of the coupling and the temperature. We find that the degree of ordering of the nanorods is enslaved by the properties of the host liquid and that it can be tuned by raising or lowering the temperature or by increasing or decreasing their concentration. By comparing the theory to recent experiments, we find the anchoring energy of multiwalled carbon nanotubes to be in the range from 10-10 to 10-7 N m-1.
Ključne besede: liquid crystals, nematic crystals, molecular dynamics, stability, elasticity, carbon nanotubes
Objavljeno v DKUM: 07.06.2012; Ogledov: 2023; Prenosov: 89
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