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Opis: The construction of the nuclear fusion plant 'ITER' has started in 2009 at Cadarache, France. The ITER machine represents a milestone in the civil use of the nuclear fusion energy. The physics of ITER is based on the fusion reaction between deuteron and triton nuclei (d-t). The deuteron-deuteron reaction (d-d) is also interesting and is foreseen for the next generation of fusion reactors. The experimental activities carried out in the context of the ITER neutronics involve intense fields of neutrons produced with a linear accelerator for deuterons, a target containing tritium or deuterium and auxiliary structures, such as the detector system, cooling system, room walls, etc. Experimental data have been obtained from the FNG (Frascati Neutron Generator, Italy), FNS (Fast Neutron Source, Japan), OKTAVIAN (Osaka University, Japan) and IRMM (Institute for Reference Materials and Measurements, EU). An independent method was developed at FNG for the simulation of the d-t neutron spectra at different angles. The FNG source routine models the Monte Carlo deuteron transport in solid tritiated targets as done in the well known SRIM code. The neutrons are generated according to the tabulated probability of the d-t reactions as for the DROSG2000 code. The FNG source routine is implemented into the MCNP distributions. The user is asked to define into the MCNP input file the deuteron energy (up to 10 MeV), the beam width and the target dimensions and composition. This source routine has been chosen as starter for the present thesis. Improvements and extensions were introduced. - The methodology, originally developed for the d-t neutron source, has been extended to d-d neutron sources. - Assuming the the SRIM code constitutes the reference calculation for the deuteron transport in matter, its implementation in the source routine has been cross-checked by extracting from the latter the same quantities as provided by the original code. II - In the present version of the source routines, the cross sections are internally generated from built in table based on modern evaluated nuclear data files instead of tables obtained from the DROSG200 code. - Since the model may be used up to 10 MeV deuteron energy, the relativistic kinematics has been implemented to avoid unnecessary approximations. - Simulations of the bare neutron source spectra and angular yields measurements have been carried out to validate the model. - New editions of the d-t and d-d source routine have been released for the latest versions of the MCNP codes and tested on LINUX and WINDOWS machines. The validation activities with the FNG and IRMM experimental data suggested a possible application of the source routine for the characterisation of neutron spectrometers in the MeV energy region. The source routine has been adopted to simulate integral benchmark experiments at FNG, FNS and OKTAVIAN. Brand new MCNP benchmark models have been developed for inclusion of all the available experimental information. It is shown that the d-t source routine is an accurate tool for the generation of the source eutrons. It also demonstrates to be useful for the evaluation of the neutron source term and associated uncertainties. The accuracy of the analyses is pursued to the point that the quality of the nuclear data employed in the simulation can be assessed. To this extent, the case of a new evaluation of the neutron interaction nuclear data for Manganese-55 is tested. A set of integral benchmark experiments has been used in the validation phase of the nuclear data. The computational models rely on the source routine, the object of the thesis. In conclusion, the source routine claims the inclusion of the major features responsible for the experimental resolution associated with the source term. The doctoral thesis explores its usage in the context of the experimental activities for ITER. The future exploitation of the source routine for the simulation of worldwide experiments might become an occasion to compare it with the source models available in the other laboratories
Ključne besede: deuteron-triton reactions, low-energy deuterons, neutron source model, Monte Carlo method, solid tritium target, solid deuterium target, fusion neutronics, benchmark experiments, diamond detectors.
Objavljeno v DKUM: 07.03.2012; Ogledov: 4802; Prenosov: 164
Celotno besedilo (8,50 MB)

Opis: V diplomskem delu bomo primerjali dva stanovanjska objekta. To sta starejša hiša, projektirana in zgrajena konec 70-ih let (leto izgradnje: 1980), in sodobna (nizkoenergijska) hiša, projektirana leta 2009 ter zgrajena v letu 2010. Navedenih je nekaj splošnih podatkov o obeh hišah, ki smo jih pridobili predvsem iz njunih dokumentov in njunega ogleda, hkrati pa primerjamo materiale, iz katerih sta zgrajeni. Za direktno primerjavo smo izbrali nekaj gradbenih elementov obeh hiš, skozi katere se prenese največ toplote. To so predvsem elementi v ogrevanih prostorih, ki mejijo proti neogrevanim, in s tem bistveno vplivajo na ugodno klimo ter počutje stanovalcev v bivalnih prostorih. S to primerjavo in s pomočjo ostalih informacij o porabi energije bomo ugotavljali, zakaj je sodobna hiša energetsko varčnejša od starejše hiše. V samih rezultatih pa bomo dobili odgovor, v čem je sodobna hiša bolj okolju prijazna in s tem manj obremenjujoča za naravo. V pričujoči diplomski nalogi lahko presodimo, ali se nam takšna novogradnja splača ali se raje odločimo za (obnovljeno) starejšo hišo. Ne smemo namreč pozabiti, da je nizkoenergijska gradnja še zmeraj dražja od klasične zidane ali montažne gradnje.
Ključne besede: gradbeni element, gradbeni material, nizkoenergijska hiša, energija, okoljski vpliv
Objavljeno v DKUM: 18.11.2011; Ogledov: 2155; Prenosov: 214
Celotno besedilo (5,56 MB)

Opis: This thesis seeks to establish the link between the structure (in a topological sense) of porous space and charged particle dynamics in porous matter, specifically in constituent elements of sustainable building materials such as clay, cement and soil. The work done is a combination of experimental research and modelling of analysed data using advanced and expanded network models to model pore structure and generalized conductivity model. The main outcome of this doctoral thesis is the demonstration that there is a correlation between the large scale structure of the pore space and the properties of the motion of charged particles through the pore space. This was achieved by conducting two experiments: the structure of pore space of selected porous materials (soil samples, clays, cements, clay-cement mixtures) was investigated using state-of-the-art X-ray computed microtomography, while the dynamics of charged particles in the samples was probed using low-frequency dielectric spectroscopy. The research done and described in the thesis is directed towards the advancement of understanding the transport phenomena and the structure of porous media which is of paramount importance for solving problems in building physics dealing with moist transport in building's envelope, the building-ground interaction, and in transport of contaminants in the vicinity of the repositories where the transfer of moist through soil can be the source of contamination.
Ključne besede: porous matter, clay-water system, hydrating cement, fractional dynamics, dielectric response, X-ray computed tomography, image analysis, complex network
Objavljeno v DKUM: 11.05.2011; Ogledov: 4887; Prenosov: 273
Celotno besedilo (34,69 MB)

Opis: Diplomska naloga predstavlja proizvodnjo pasivne montažne hiše v proizvodnem obratu ter postopek njene montaže na gradbišču. Pojasnjen je tudi sistem ogrevanja in prezračevanja, ki je tipičen za pasivno hišo. Podajamo meritve zunanje in notranje temperature ter vlažnosti v zimskem obdobju v pasivni zgradbi. Na osnovi investicijskega vlaganja primerjamo pasivno zgradbo z zgradbo po osnovnem sistemu Marles in ugotavljamo čas vračila investicije ter smotrnost naložbe v pasivno gradnjo.
Ključne besede: gradbeništvo, tehnologija grajenja, pasivna zgradba, montažna gradnja, ekonomska upravičenost
Objavljeno v DKUM: 06.04.2011; Ogledov: 3515; Prenosov: 405
Celotno besedilo (8,15 MB)

Opis: Diplomsko delo obravnava zakonodajne okvire na področju učinkovite rabe energije v stavbah in pristope k preračunu energetske učinkovitosti ovoja stavb s pomočjo računalniških programskih orodij. Predstavili smo ureditev zakonodaje za področje URE, s poudarkom na direktivi EPBD ter pravilniku PURES. Predstavili smo pristope k računanju energetske učinkovitosti ovoja stavb in podrobneje analizirali program ECOTECT. V programu smo uvozili 2D načrte, naredili 3D model objekta ter izvedli preračun toplotnih karakteristik. Na enostavnejšem modelu smo primerjali rezultate programa ECOTECT s programom URSA, kateri je po metodologiji preračuna skladen s pravilnikom PURES.
Ključne besede: učinkovita raba energije (URE), obnovljivi viri energije (OVE), direktiva EPBD, modeliranje objekta, energetska analiza objekta
Objavljeno v DKUM: 09.12.2010; Ogledov: 3478; Prenosov: 388
Celotno besedilo (8,50 MB)