Repozitorij Univerze v Novi Gorici

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 Iskalni niz: išči po NaslovAvtorOpisKljučne besedePolno besediloLeto izida INALIIN NE išči po NaslovAvtorOpisKljučne besedePolno besediloLeto izida INALIIN NE išči po NaslovAvtorOpisKljučne besedePolno besediloLeto izida INALIIN NE išči po NaslovAvtorOpisKljučne besedePolno besediloLeto izida Vrsta gradiva: Vse vrste gradiv Habilitacijsko delo (m4) Višješolska diplomska naloga (m6) Specialistično delo (m3) Diplomsko delo * (dip) Magistrsko delo * (mag) Doktorska disertacija * (dok) Raziskovalni podatki ali korpus (data) * po starem in bolonjskem študiju Jezik: Vsi jezikiSlovenski jezikAngleški jezikNemški jezikHrvaški jezikSrbski jezikBolgarski jezikBosanski jezikČeški jezikFinski jezikFrancoski jezikItalijanski jezikJaponski jezikLitvanski jezikMadžarski jezikNemški jezik (Avstrija)Norveški jezikPoljski jezikRuski jezikSlovaški jezikSrbski jezik (cirilica)Španski jezikŠvedski jezikTurški jezikNi določenNeznan jezik Išči po: RUNG    AU - Akademija umetnosti    FAN - Fakulteta za aplikativno naravoslovje    FH - Fakulteta za humanistiko    FN - Fakulteta za naravoslovje    FPŠ - Fakulteta za podiplomski študij    FVV - Fakulteta za vinogradništvo in vinarstvo    FZO - Fakulteta za znanosti o okolju    PTF - Poslovno-tehniška fakulteta    UNG - Univerza v Novi Gorici    VŠU - Visoka šola za umetnost    VŠVV - Visoka šola za vinogradništvo in vinarstvoCOBISS    Univerza v Novi Gorici Opcije: Prikaži samo zadetke s polnim besedilom Ponastavi

 1 - 10 / 23312345678910 1.Theoretical and experimental aspects of numerosity and quantification in Lebanese ArabicAli Al Moussaoui, 2021, doktorska disertacijaOpis: A question that is receiving an increasing attention in linguistics research concerns the language components of counting. This topic is approached from syntactic, semantic and pragmatic points of view. While some accounts advocate for purely syntactic or semantic approaches of countability, other adopt hybrid accounts in which labor is divided between syntax and semantics. At the same time, research finds that there is a pragmatic component enriching the interpretation of countability and numerosity in language. This dissertation attempts to contribute into the lines of research concerned in the syntactic, semantic and pragmatic aspects of countability with a focus on Lebanese Arabic (Henceforth LA), a language that has received little attention in the literature of counting. In this dissertation, a broken agreement pattern in LA between the cardinal numerals and the post-numeral counted noun phrases is examined on the basis of a syntactic-semantic model of countability developed by Stepanov and Stateva (2018). We argue that the current existing model can be used to account for the countability broken agreement pattern in LA when necessary modifications are applied to it. The success of this model in accounting for the numeral-noun-phrase agreement in LA is added to its success in similar missions in countability in Russian (Stepanov and Stateva 2018) and previously in Japanese (Watanabe 2010). The pragmatic component of countability in LA is also examined from the angle of pragmatic strengthening. The traditional difference between singular nominals and plural nominals which makes a distinction between domains of atoms and domains of sums is seriously challenged by current semantic and pragmatic research. The plural is found to be more complex than a simplistic view of more than one, and its interpretation has a pragmatic component which involves enriching the meaning of plurality against singularity. In our dissertation, we intend to examine an enriching pragmatic process of plural against duality in LA, a language that still preserves special morphological marking for duality. So, our research investigates the pragmatic strengthening of the plural morphology in LA against the dual morphology which results in at-least-three meaning of the plural. On the assumption that pragmatic reasoning contributes to the interpretation of plural nominals, we extend our research to the area of bilingual LA speakers who can be an ideal environment to look into the cognitive processes involved in the interaction between two linguistic systems that have diverging features pertaining to a given linguistic phenomenon, which is countability in our study. We predict crosslinguistic variation in the interpretation of plural morphology. If languages like English associate plural with an at-least-two meaning as a result of pragmatic enrichment with an anti-singularity inference, then, in languages that morphologically differentiate among singular, plural and dual number, the morphological plural is predicted to correspond to an at-least-three meaning. In this study, we ask whether the predicted variation in the interpretation of plural morphology among the non-dual and dual-featuring languages is a locus of negative pragmatic transfer of features from LA as a mother tongue and English/ French as foreign languages.Ključne besede: countability, numerosity, Lebanese Arabic, countability model, negative pragmatic transfer, and foreign language exposureObjavljeno: 16.07.2021; Ogledov: 300; Prenosov: 7 Polno besedilo (3,00 MB)Gradivo ima več datotek! Več... 2.Structural, morphological and chemical properties of metal/topological insulator interfacesKatja Ferfolja, 2021, doktorska disertacijaOpis: Topological insulators (TIs) represent a new state of matter that possess a different band structure than regular insulators or conductors. They are characterized with a band gap in the bulk and conductive topological states on the surface, which are spin polarized and robust toward contamination or deformation of the surface. Since the intriguing properties of the TIs are localized at the surface, it is important to obtain knowledge of the possible phenomena happening at the interface between TIs and other materials. This is especially true in the case of metals, due to the fact that such interfaces will be present in the majority of foreseen TI applications. The presented study combines microscopy and spectroscopy techniques for characterization of morphology, stability and chemical interaction at the interface between TI and metals deposited by means of physical vapor deposition. Our research is based on the interface of Bi2Se3 topological insulator with Ag, Ti and Pt – metals that can be encountered in devices or applications predicted to utilize the special properties of topological insulators. STM and SEM imaging of Ag/Bi2Se3 interface showed that Ag atoms arrange on the surface in the form of islands, whereas significantly bigger agglomerates are found at the surface steps. The interface was found to be unstable in time and resulted in the absorption of the metal into the crystal at room temperature. Evidences of a chemical reaction at the Ag/Bi2Se3 interface are presented, showing that new phases (Ag2Se, AgBiSe2 and metallic Bi) are formed. Deposition of Ti on Bi2Se3 resulted in different morphologies depending on the film thickness. At a very low coverage (<1 Å) islands are formed. However, the islands growth is hindered before the completion of a full layer due to the occurrence of a chemical reaction. No surface features could be detected by SEM for Ti coverage up to 20 nm. In contrary, when Ti thickness reached 40 nm, compressive stress triggered buckling of the deposited film. XPS analysis revealed that a redox solid-state reaction occurs at the Ti/Bi2Se3 interface at room temperature forming titanium selenides and metallic Bi. The reaction has significant kinetics even at cryogenic temperature of 130 K. Pt forms a homogenous film over the whole substrate surface, which is stable in time at room temperature. Although the interface of Pt with Bi2Se3 was found to be i less reactive compared to Ag and Ti, an interfacial phase formed upon annealing to ∼90 °C was detected by TEM cross section experiment. A model for prediction of interfacial reactions between a metal and Bi2Se3 based on the standard reduction potential of the metals and Gibbs free energy for a model reaction is presented. Based on these two values the reaction can be expected to result in the formation of binary and/or ternary selenides and Bi. Presented work shows on the importance of metal/topological insulator interfaces characterization taking into account the possibility of a chemical reaction with all of its consequences. Results should be considered for future theoretical and applicative studies involving such interfaces as well as for the possible engineering of 2D TI heterostructures.Ključne besede: topological insulators, topological surface states, Bi2Se3, thin films, Ag, Ti, Pt, morphology, interfaces, solid-state reaction, metal selenides, reactivity, stability, electron microscopy, dissertationsObjavljeno: 09.06.2021; Ogledov: 383; Prenosov: 25 Polno besedilo (0,00 KB)Gradivo ima več datotek! Več... 3.Sn-modified TiO[sub]2 thin film photocatalysts prepared by low-temperature sol-gel processingKsenija Maver, 2021, doktorska disertacijaOpis: Due to many advantageous physiochemical properties, titanium dioxide (TiO2) is the most widely used photocatalyst in numerous applications, such as wastewater treatment and air purification, self-cleaning surfaces and energy conversion (H2 generation). However, one of its disadvantages is the high electron-hole recombination rate, and coupling with other semiconductors is one of the strategies to improve it. The objective of this dissertation was to investigate how the photocatalytic activity of pure TiO2 can be improved by tin modification and to explain the mechanism of increased or hindered photoactivity in correlation with the structural properties of the modified TiO2 photocatalysts. A new low-temperature sol-gel synthesis route was developed to prepare Sn- or SnO2-modified TiO2 photocatalysts. In both cases, organic tin and titanium precursors were used. Tin in the form of Sn cations was used to prepare Sn-modified TiO2. In this case, the precursors went through the sol-gel reaction together to form a Sn-TiO2 sol. In the case of SnO2 modification, the SnO2 sol was prepared separately and additionally mixed with the TiO2 sol to form a TiO2/SnO2 bicomponent semiconductor system. Different molar ratios of tin to titanium were prepared to investigate the correlation between the tin concentration and the photocatalytic properties of the photocatalysts in the form of thin films. The results were used to optimize the synthesis conditions to obtain an improved activity of the modified TiO2 photocatalysts under UV-irradiation. The photocatalytic activity of the thin films was determined by measuring the degradation rate of an azo dye. An increase of up to 40 % in the photocatalytic activity of the dried samples (at 150 °C) was achieved when the TiO2 was modified with the Sn or SnO2 in a concentration range of 0.1 to 1 mol.%. At higher Sn or SnO2 loadings and after calcination of the samples at 500 °C, the photocatalytic activity of the photocatalyst was reduced compared to the unmodified TiO2. Different characterization techniques (UV-Vis, XRD, nitrogen physisorption, TEM, SEM and XAS) were employed to clarify the mechanism responsible for the enhanced and hindered photocatalytic performance of the Sn- and SnO2-modified TiO2 photocatalysts. The results showed that a nanocrystalline structure is already achieved in the samples by the low-temperature film treatment (drying at 150 °C) and that the photocatalytic efficiency is mainly influenced by the crystalline phase composition: anatase/rutile in the case of Sn-modified and TiO2/SnO2 in the case of SnO2-modified TiO2. The crystal size and specific surface area differ insignificantly between the equally thermally treated samples and partly explain the differences in photoefficiency of the calcined samples compared to the dried samples. The structural study at the atomic level, using the Sn K-edge EXAFS, revealed that Sn cations act as nucleation sites for the anatase to rutile transformation in the Sn-modified TiO2 photocatalysts, while in the SnO2-modified TiO2 samples the nanocrystalline cassiterite SnO2 is bound to the TiO2 nanocrystallites via the Sn-O-Ti bond. In both cases, the advantage of coupling the two semiconductors was achieved by separating the charge carriers and thus prolonging their lifetime for accessibility to participate in the redox reactions. The maximum activity enhancement was achieved in the low concentration range (0.1–1 mol.%), which means that an optimal ratio and contact of the two phases are obtained for the given physical parameters, such as particle size, shape and specific surface area of the catalyst.Ključne besede: Sn-modified TiO2, SnO2-modified TiO2, low-temperature sol-gel, thin films, photocatalytic activity, anatase/rutile system, Sn K-edge EXAFS, dissertationsObjavljeno: 09.06.2021; Ogledov: 331; Prenosov: 24 Polno besedilo (0,00 KB)Gradivo ima več datotek! Več... 4.Numerical modelling of dendritic solidification based on phase field formulation and adaptive meshless solution procedureTadej Dobravec, 2021, doktorska disertacijaOpis: The main aim of the dissertation is to develop a novel numerical approach for an accurate and computationally efficient modelling of dendritic solidification, which is one of the most commonly observed phenomena in the industrial casting of the metallic alloys. The size and the morphology of dendritic structures as well as the distribution of the solute within them critically effect the mechanical and the electro-chemical properties of the solidified material. The numerical modelling of dendritic solidification can be applied for an in-depth understanding and optimisation of the casting process under various solidification conditions and chemical compositions of the alloy under consideration. The dendritic solidification of pure materials and dilute multi-component alloys is considered in the dissertation. The phase field formulation is applied for the modelling of dendritic solidification. The formulation is based on the introduction of the continuous phase field variable that is constant in the bulk of the solid and liquid phases. The phase field variable has a smooth transition from the value denoting the solid phase to the value denoting the liquid phase at the solid-liquid interface over the characteristic interface thickness. A phase field model yields a system of coupled non-linear parabolic partial differential equations that govern the evolution of the phase field and other thermodynamic variables. The meshless radial basis function-generated finite-differences (RBF-FD) method is used for the spatial discretisation of the system of partial differential equations. The forward Euler scheme is applied for the temporal discretisation. Fifth-degree polyharmonic splines are used as the shape functions in the RBF-FD method. A second-order accurate RBF-FD method is achieved by augmenting the shape functions with monomials up to the second degree. The adaptive solution procedure is developed in order to speed-up the calculations. The procedure is based on the quadtree domain decomposition of a rectangular computational domain into rectangular computational sub-domains of different sizes. Each quadtree sub-domain has its own regular or scattered distribution of computational nodes in which the RBF-FD method and the forward Euler scheme apply for the discretisation of the system of partial differential equations. The adaptive solution procedure dynamically ensures the prescribed highest density of the computational nodes at the solid-liquid interface and the lowest-possible density in the bulk of the solid and liquid phases. The adaptive time-stepping is employed to further speed-up the calculations. The stable time step in the forward Euler scheme depends on the density of the computational nodes; hence, different time steps can be used in quadtree sub-domains with different node densities. The main originality of the present work is the use of the RBF-FD method for the thorough analysis of the impact of the type of the node distribution and the size of a local sub-domain to the accuracy when the phase field modelling of dendritic solidification for arbitrary preferential growth directions is considered. It is shown how the use of the scattered node distribution reduces the undesirable mesh-induced anisotropy effects, present when the partial differential equations are discretisied on a regular node distribution. The main advantage of the RBF-FD method for the phase field modelling of dendritic growth is the simple discretisation of the partial differential equations on the scattered node distributions. The RBF-FD method is, for the first time, used in combination with the spatial-temporal adaptive solution procedure based on the quadtree domain decomposition. The adaptive solution procedure successfully speeds-up the calculations; however, the advantages of the use of the scattered node distribution are partly compromised due to the impact of regularity in the quadtree domain decomposition.Ključne besede: dendritic solidification, phase field method, meshless methods, RBF-FD, adaptive solution procedureObjavljeno: 07.04.2021; Ogledov: 559; Prenosov: 28 Polno besedilo (0,00 KB)Gradivo ima več datotek! Več... 5.Pesniška samorefleksija v sodobni slovenski poeziji po drugi svetovni vojniMateja Eniko, 2021, doktorska disertacijaOpis: Pesniška samorefleksija v poeziji predstavlja reflektiranje vprašanj, povezanih s pesniško umetnostjo, znotraj pesniškega diskurza samega. Poezija se tako odziva na poetološka vprašanja vzporedno s teoretskim diskurzom. Koncept pesniške samorefleksije je sinonimen terminu metapoezija in glede na elemente literarne komunikacije vsebinsko obsega štiri temeljna tematska polja, ki v literarnih uresničitvah doživljajo razširitve in specifikacije. To so pesnik, pesniško delo oziroma pesniška umetnost, recepcija poezije in kontekst. V pesmih je pesniška samorefleksija pomembno prisotna vse od antike dalje, še posebej pomembna prvina pa postane v sodobni poeziji 20. stoletja. V teoretskem diskurzu v 20. stoletju so bila posebne pozornosti deležna vprašanja avtorja, njegove subjektivitete in avtonomije. Prelomni razmisleki so se v veliki meri dogajali glede na romantični koncept avtonomnega božansko navdahnjenega genija. Skladno s tem dejstvom se doktorska disertacija med osrednjimi tematskimi polji pesniške samorefleksije oziroma metapoezije osredotoči na vprašanje avtorja oziroma pesnika. V disertaciji je najprej definiran koncept pesniške samorefleksije. Ob upoštevanju dosedanjih teoretskih študij prinaša premišljene zamejitve koncepta, oblik, strategij in funkcij pesniške samorefleksije. Sledi pregled oblikovanja koncepta avtorja s poudarkom na oblikovanju romantičnega pojma genija in prelomih, ki jih je bil ta deležen v 20. stoletju. Na teoretske opredelitve se nasloni interpretativna analiza sodobne slovenske poezije po drugi svetovni vojni. Opravljene so študije primerov uresničitve pesniške samorefleksije v poeziji osmih pesnic in pesnikov različnih pesniških generacij in literarnoestetskih usmeritev: Kajetana Koviča, Daneta Zajca, Tomaža Šalamuna, Nika Grafenauerja, Milana Jesiha, Taje Kramberger, Barbare Korun in Primoža Čučnika. Pesniška samorefleksija predstavlja pomemben element v sodobnem pesniškem diskurzu. Doktorska disertacija prikaže, na kakšne načine se pesniška samorefleksija uresničuje v poeziji sodobnih slovenskih pesnikov ter kakšne učinke sproža vzpostavljanje metapoetskega zavedanja. Analiza pesniške samorefleksije prispeva k teoretskim razmislekom o poeziji, hkrati pa kaže na specifično moč poezije za ubesedovanje in prikazovanje pesniških konceptov. Produktivna se izkaže za razmislek avtorske vloge: na eni strani pesnikove družbene vloge, na drugi strani pa preigravanje različnih ravni pesnika v odnosu do teksta.Ključne besede: pesniška samorefleksija, metapoezija, avtotematska poezija, avtotematizacija, avtoreferenca, metazavedanje, pesnik, avtor, romantični koncept genija, avtonomija, deziluzija, sodobna slovenska poezija, Kajetan Kovič, Dane Zajc, Tomaž Šalamun, Niko Grafenauer, Milan Jesih, Taja Kramberger, Barbara Korun, Primož ČučnikObjavljeno: 31.03.2021; Ogledov: 571; Prenosov: 30 Polno besedilo (0,00 KB)Gradivo ima več datotek! Več... 6.Household and road dust as indicators of airborne particulate matter elemental compositionKlemen Teran, 2020, doktorska disertacijaOpis: Household dust (HD) and road dust (RD) are widespread and easily accessible urban sediments, which are influenced by deposition of airborne particulate matter (PM). Since airborne PM is considered to be one of the most important pollutants in urban areas, with significant adverse effects on human health, a better understanding of its elemental composition and dispersion mechanisms is needed. The present study examines whether the HD and RD elemental composition can be used as a quick alternative method for the determination of corresponding PM elemental composition over a selected area. In summer 2016, HD, RD, and topsoil samples were collected from 249 sampling locations distributed across rural, urban, and industrial areas in Slovenia. The collected samples were sieved for particle diameters below 63 μm and analysed for 53 elements with ICP-MS after aqua regia digestion. SEM/EDS analyses were applied for the determination of characteristic particles at the microlevel. Finally, the elemental composition of HD and RD was compared with the PM10 elemental composition obtained from National Network for Ambient Air Quality Monitoring governed by Slovenian Environmental Agency (ARSO) to determine any potential connection between them. The results show that HD and RD are considerably enriched with a large set of elements compared to the topsoil. Correlations and factor analyses show that spatial distribution of factor scores in RD revealed strong regional trends, connected with soil resuspension (Al, Ce, Ga, K, La, Li, P, Rb, Sc and Y) or with anthropogenic sources such as traffic (Ag, Bi, Cu, Sb and Sn), steel mill emissions (Cr, Mo, Mn, Ni and W) and construction material decomposition (Ca and Sr). In contrast, HD elemental composition was highly variable between sampling locations. Variability was probably caused by indoor sources, such as smoking (Ce and La), biomass combustion (K, P and Rb), construction material decomposition (Ca and Sr) and residents’ professional occupation: dental care employees (Ag, Au, Pd) and employees in the metal-processing industry (Cr, Mo, Ni). Among deposited particles in RD, urbanization processes, such as fossil fuel combustion and traffic emissions, including brake pad abrasion and tyre wear, contributed the largest share of particles with anomalous elemental composition. Brake pad abrasion, for instance, contributed Ba-, Cu-, Sn-, and Zn-enriched irregular, angular and tabular particles, while tyre wear produced elongated rubber particles with traces of Ba, Cu, and Zn. RD from urban areas showed significantly higher elemental levels of Ag, Bi, Ca, Cd, Cr, Cu, Hg, Fe, Mo, Nb, Pb, Pt, Sb, Sn, Sr, Ti, Zn, and W in comparison to the rural environment, indicating the strong impact of urbanization on RD elemental composition. Another important anthropogenic source of deposited particles in RD were steel mills. Strong anomalies of Cr, Mo and Ni were detected in their vicinity. Their elemental levels decreased with distancing from the plan location, reaching urban background levels between 15 and 20 km from the mills. SEM/EDS analyses identified enrichments of Cr, Mn, Mo, Ni, V, and W in spherical particles and particles with partially melted surfaces, which were found only in the proximity of steel mills, indicating their influence of the PM deposition. Comparison of RD and the corresponding PM10 elemental composition showed that the RD fraction with particle diameters below 63 μm reflects PM10 elemental composition for the last 30 to 90 days for Cr, Cu, Mo and Zn and can be used as a predictor for PM10 elemental levels. This is not true for HD, as indoor particle sources prevail over the deposition of ambient PM10.Ključne besede: household dust, road dust, particulate matter, PM10, pollution, Slovenia, steel mills, topsoil, traffic, urbanizationObjavljeno: 02.12.2020; Ogledov: 993; Prenosov: 64 Polno besedilo (16,34 MB) 7.Advantages and disadvantages of experiments with ultrashort two-color pulsesMatija Stupar, 2020, doktorska disertacijaOpis: Advances in the development of lasers have led to a new class of radiation sources generating coherent, tunable, ultrashort light pulses in the spectral region ranging from infrared to soft X-rays. This includes high-order harmonics generation in gas (HHG), on which relies the CITIUS facility at University of Nova Gorica (Slovenia), and free-electron lasers (FELs), such as the facility FERMI at Elettra-Sincrotrone Trieste (Italy). The distinctive structure of HHG and FEL radiation paved the way to time-resolved experiments, which are performed to investigate events occurring on a short, or very short, temporal scale, from picoseconds to femtoseconds. This work focuses on the advantages and disadvantages of some experimental techniques based on using these novel light sources to investigate the microscopic and/or ultrafast dynamics of matter samples, which have been previously driven out of equilibrium. Advantages rely on the implementation of various applications based on two-color schemes and, more specifically, include the possibility of acquiring two-dimensional frequency maps, measuring electrons’ effective masses, or investigating electronic properties decoupled from the influence of the lattice. Particular focus will be put on experimental methods relying on photoelectric effect and photoelectron spectroscopy. In all experiments, we took advantage of one or more specific properties of HHG and FEL sources, such as controllable chirp, to study laser dressed states in helium, variable polarization, to study electronic properties of iron-based pnictides and ultrashort pulses (< 10 fs) to study the purely electronic dynamics in transition metal dichalcogenides. On the other hand, the study of the interface between a molecule and a topological insulator revealed some intrinsic limitations and physical drawbacks of the technique, such as spurious effects originating from the high power pulses, like multiphoton absorption and the space charge effect, or the reduction of experimental resolution when pushing for shorter and shorter pulse durations. Some disadvantages are also connected to the current state-of-the-art in the field of ultrashort laser systems, where a trade-off needs to be found between repetition rate and laser power. Finally, state-of-the-art experiments based on the ability to generate ultrashort pulses carrying orbital angular momentum in visible, near-infrared as well as extreme UV range will be presented. The use of these pulses opens the door to the investigation of new physical phenomena, such as probing magnetic vortices using extreme ultraviolet light from a free-electron laser or imprinting the spatial distribution of an ultrashort infrared pulse carrying orbital angular momentum onto a photoelectron wave packet.Ključne besede: ultrafast lasers, two-color experiments, photoemission, high-order harmonic generation, free-electron lasers, hot-electrons dynamics, surface science, pump-probe photoemission, ultraviolet photoemission, orbital angular momentumObjavljeno: 02.12.2020; Ogledov: 959; Prenosov: 28 Polno besedilo (19,78 MB) 8.Constraining dark matter particle properties with Fermi-LAT and the Cherenkov Telescope ArrayChristopher Eckner, 2020, doktorska disertacijaKljučne besede: dark matter, astroparticle physics, high-energy gamma-ray astronomy, cosmic rays, Imaging Atmospheric Cherenkov Telescope, Cherenkov Telescope Array, Fermi Large Area TelescopeObjavljeno: 29.09.2020; Ogledov: 1026; Prenosov: 35 Polno besedilo (68,77 MB) 9.A study of stellar debris dynamics during a tidal disruption eventAurora Clerici, 2020, doktorska disertacijaOpis: The number of observed tidal disruption events is increasing rapidly with the advent of new surveys. Thus, it is becoming increasingly important to improve TDE models using different stellar and orbital parameters. We study the dynamical behaviour of tidal disruption events produced by a massive black hole like Sgr A* by changing different initial orbital parameters, taking into account the observed orbits of S stars. Investigating different types of orbits and penetration factors is important since their variations lead to different timescales of the tidal disruption event debris dynamics, making mechanisms such as self-crossing and pancaking act strongly or weakly, thus affecting the circularisation and accretion disk formation. We have performed smoothed particle hydrodynamics simulations. Each simulation consists in modelling the star with $10^5$ particles, and the density profile is described by a polytrope with $\gamma$ = 5/3. The massive black hole is modelled with a generalised post-Newtonian potential, which takes into account relativistic effects of the Schwarzschild space-time. Our analyses find that mass return rate distributions of solar-like stars and S-like stars with same eccentricity have similar durations, but S-like stars have higher mass return rate, as expected due to their larger mass. Regarding debris circularisation, we identify four types of evolution, related to the mechanisms and processes involved during circularisation: in type 1 the debris does not circularise efficiently, hence a disk is not formed or is formed after relatively long time; in type 2 the debris slowly circularises and eventually forms a disk with no debris falling back; in type 3 the debris relatively quickly circularises and forms a disk while there is still debris falling back; finally, in type 4 the debris quickly and efficiently circularises, mainly through self-crossings and shocks, and forms a disk with no debris falling back. Finally, we find that the standard relation of circularisation radius $r_{\rm circ} = 2r_{\rm t}$ holds only for $\beta = 1$ and eccentricities close to parabolic.Ključne besede: 07.05.Tp Computer modeling and simulation, 95.30.Lz Hydrodynamics, 98.35.Jk Galactic center, bar, circumnuclear matter, and bulge, 98.62.Js Galactic nuclei (including black holes), circumnuclear matter, and bulges, 98.62.Mw Infall, accretion, and accretion disksObjavljeno: 29.09.2020; Ogledov: 1043; Prenosov: 43 Polno besedilo (37,55 MB) 10.Seismic Vulnerability of a Historical Masonry Building: A Critical Comparison of Analytical MethodologiesMarco Boscolo Bielo, 2020, doktorska disertacijaOpis: In these last twenty years a new sensibility for the seismic themes around buildings has emerged from a cultural and technical point of view. As a result of some earthquakes happened in Italy, the promulgation of technical codes has accelerated and, essentially, the standards of Eurocodes were accepted. Consequently, also in the field of historical buildings, a set of specific guidelines have been issued. In the current state of art, designers are faced with many methods of calculation which the technical codes offer for the assessment of the seismic vulnerability of historical buildings. Designers can use simplified or complex approaches which assume different starting hypothesisto obtain different results. This thesis aims to investigate the various aspects that the designer meets during the study of the static behaviour of an historical building and the assessment of its seismic vulnerability. A study case is also proposed which regards a Venetian Villa of the XVIth Century located in “Riviera del Brenta” near Venice, with a critical comparison of the results obtained by the application of the various methods of calculation. The thesis begins with an outline of the historical development of seismic technical codes in Italy and shows how the sensibility has developed in the Italian culture. In particular it is illustrated the difference between the approach of the legislation "a posteriori" (where a “patchy zoning” was generally performed after the occurrence of earthquakes), and the probabilistic approach based on the peaking ground acceleration expected in every Italian site. The Second and the Third Chapters contain the analysis of the current seismic legislations and in particular the guidelines for historical buildings. The Chapter 4 provides a general discussion on the masonry and the definition of the mechanical parameters. There are many critical aspects relating to a characterization of models which can realistically represent the historical masonry. They are due to a heterogeneity of variables such as, for instance, the mechanical parameters, the physiological behaviour, the connections, etc. In the Chapter 5 the basic concepts of seismic behaviour of historical buildings are discussed. In particular the Pagano’s classification of masonry buildings is illustrated with special regard of the following factors: stiffness of horizontal structures; efficiency of “masonry beams”; efficiency of intersection between walls. From the Chapter 6 the analysis of the study case begins. Here we can find the description of the Venetian Villa (historical evolution of the buildings, description of geometrical characteristics, structural behaviour, etc. In the Chapter 7, the first level of analysis is performed for the study-case. The method of calculation is contained in the guidelines for historical buildings. A critical discussion of the results is also illustrated. In the Chapter 8 is performed a linear kinematic analysis based on various possible kinematic mechanisms identified through the study of cracking and the lacks of the structural connections. The Chapter 9 shows a non-linear static analysis (pushover) for the study-case which refers to two limit behaviour models: the first one with infinitely rigid diaphragms and efficient masonry beams; the second one based on infinitely flexible diaphragms and weak masonry beams. The results are compared and critically discussed. In the same way the Chapter 10 and 11 perform a linear static analysis and a linear dynamic analysis for the two models of the Chapter 9, so the results can be compared. In the last Chapter a general discussion about all the results of the performed analysis is conducted. Here the work points out the conceptual limits of each method of calculation and the possibility of use related to the objectives which must be reached. Finally some design indications related to the results of the analysis are illustrated.Ključne besede: Seismic, Vulneraility, Analitical, MethodologiesObjavljeno: 02.07.2020; Ogledov: 1032; Prenosov: 18 Polno besedilo (128,89 MB)
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