Iskanje po katalogu digitalne knjižnice

Ključne besede: camera, particle, measurement, silhuette, volume, position
Objavljeno v DKUM: 22.05.2024; Ogledov: 157; Prenosov: 8
Celotno besedilo (3,99 MB)
Gradivo ima več datotek! Več...

Opis: Post-liquefaction settlement characteristics of micaceous sands are not well investigated topic. Currently available charts relating post-liquefaction volumetric strain to relative density were developed for clean sand. Estimation of post-liquefaction settlement of micaceous sands, therefore, may stay on the unsafe side, since there is evidence indicating that mica grains could increase volume change tendency. Influence of mica content on post-liquefaction volumetric strain of sand-mica mixtures is studied in this article. Soil samples were prepared at various relative densities. Influence of fine content that could be present in the field was also investigated on tamped natural field samples recovered from boreholes drilled in a highly populated alluvial site known as the Old Gediz River Delta of Izmir. It was found that increasing mica content at a certain relative density resulted in higher volumetric strains as compared with the data on clean sands. It is deduced that influence of mica grains on sand behavior depends on initial void ratio of sand. Effects of mica grains decrease with increasing of relative density. Simple empirical relationships were derived relating mica content and relative density to volumetric strain. It was also noticed that fine content accelerated and increased post-liquefaction volumetric strains.
Ključne besede: sand, mica, non-plastic fines, post-liquefaction volume change
Objavljeno v DKUM: 14.06.2018; Ogledov: 900; Prenosov: 95
Celotno besedilo (434,60 KB)
Gradivo ima več datotek! Več...

Opis: Topological defects (TDs) appear almost unavoidably in continuous symmetry breaking phase transitions. The topological origin makes their key features independent of systems' microscopic details; therefore TDs display many universalities. Because of their strong impact on numerous material properties and their significant role in several technological applications it is of strong interest to find simple and robust mechanisms controlling the positioning and local number of TDs. There are strong evidences that in physics the fields are fundamental entities of nature and not particles. If this is the case then topological defects (TDs) might play the role of fundamental particles. An adequate testing ground to study and gain fundamental understanding of TDs are nematic liquid crystals. We present a numerical study of TDs within effectively two dimensional closed soft films exhibiting in-plane orientational ordering. Popular examples of such class of systems are liquid crystalline shells and various biological membranes. We analyze the impact of extrinsic and intrinsic curvature on positions of topological defects (TDs) in two-dimensional (2D) nematic films. We demonstrate that both these curvature contributions are commonly present and are expected to be weighted by comparable elastic constants. A simple Landau-de Gennes approach in terms of tensor nematic order parameter is used to numerically demonstrate impact of the curvatures on position of TDs on 2D ellipsoidal nematic shells. We introduce the Effective Topological Charge Cancellation mechanism controlling localised positional assembling tendency of TDs and the formation of pairs (defect,antidefect) on curved surfaces. Furthermore, we estimate a critical depinning threshold to form pairs (defect,antidefect) using the electrostatic analogy. Finally, we show how one could efficiently switch among qualitatively different structures by using a relative volume of ordered shells, which represents a relatively simple naturally accessible control parameter. In doctoral thesis, we developed theoretical model of erythrocyte membrane by using a hybrid Helfrich-Landau type mesoscopic approach, taking into account in-plane membrane ordering. We demonstrate that the derived extrinsic membrane energy term, which strongly depends on the local orientations of the molecules, is essential for the predicted broadening of the range of the relative volumes corresponding to the stable discocyte shapes, which is otherwise very narrow if only intrinsic curvature energy term dominates.
Ključne besede: Topological defects, Continuum fields, Nematic liquid crystals, Biological membranes, Nematic shells, Landau-de Gennes formalism, Topological charge, Nanoparticles, Gaussian curvature, Electrostatic analogy, Intrinsic curvature, Extrinsic curvature, Crystal growth nucleation, Relative volume
Objavljeno v DKUM: 09.03.2018; Ogledov: 2391; Prenosov: 241
Celotno besedilo (23,66 MB)

Opis: The densities of n-heptane, n-octane and their binary mixtures were measured at 298.15, 323.15 and 348.15 K and within the pressure range 0.1 to 40 MPa using a vibrating tube densimeter. The reliability of this technique has been verified in our previous works. The partial molar volumes, excess molar volumes, isothermal compressibilities, isobaric thermal expansivities and internal pressures were calculated from the obtained densities. This study presents the dependence of densities, partial molar volumes, excess molar volumes, isothermal compressibilities, isobaric thermal expansivities and internal pressures on composition, temperature and pressure.
Ključne besede: density measurements, partial molar volume, excess molar volume, isothermal compressibility, isobaric thermal expansivity, internal pressure, n-heptane, n-octane
Objavljeno v DKUM: 10.07.2015; Ogledov: 1689; Prenosov: 123
Celotno besedilo (191,46 KB)
Gradivo ima več datotek! Več...

Opis: V članku je predstavljen algoritem za senčenje prostorskih podatkov, ki je zaradi svoje enostavnosti in hitrosti primeren tudi za uporabo na osebnem računalniku. Množice podatkov, ki jih je zmožen vizualizirati, so dovolj velike za učinkovito rabo v medicinskih aplikacijah. Algoritem temelji na sekundarnem geometrijskem modelu, ki smo ga poimenovali seznam vidnih vokslov. Vizualizacijo poskuša pospešiti s predhodnim izločanjem vokslov, nezanimivih za uporabnika. Ti tako imenovani beli voksli predstavljajo zrak, notranjost objektov in dele površja objektov, ki niso vidni iz trenutnega položaja opazovalca. Delovanje in učinkovitost algoritma smo predstavili na nekaj praktičnih primerih uporabe pri vizualizaciji medicinskih podatkov.
Ključne besede: računalniška grafika, prostorski podatki, senčenje prostorskih podatkov, znanstvena vizualizacija, vizualizacija prostorskih podatkov, izdelava modelov, voksli, vizualizacija medicinskih podatkov, computer graphics, volume data, volume rendering, visualisation, volume data visualisation, voxels, medical data sets
Objavljeno v DKUM: 01.06.2012; Ogledov: 2123; Prenosov: 53
Povezava na celotno besedilo