Faculty of Mining, Geology and Petroleum Engineering Repository
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Measurement uncertainty in testing bentonite index properties
No full textGeosynthetic clay liners (GCLs) are factory-manufactured products used in various applications mainly for containment purposes. The type of construction, as well as the anticipated function determine the technical requirements that GCLs must fulfil. There are many laboratory test methods that can be used for the characterization of GCLs. Among other tests, the swell index test and the Enslin-Neff water-adsorption test are used for quality control in manufacturing and as performance indicators for the mineral component, i.e. bentonite clay. The paper presents the findings of within-laboratory evaluation of measurement uncertainty in bentonite swell index and water-adsorption testing, and the evaluation of some requirements of the standard test method, such as the influence of time and temperature of drying for the sample preparation phase or the influence of different observers. No statistically significant deviations from normality were found for the Enslin-Neff water-adsorption test. The F-test and t-test were performed to compare variances and means for the same observer at two drying temperatures, as well as for two observers at the same temperature, with some differences. The results of the detailed statistical analysis indicate that the assessment of the measurement uncertainty type A was properly estimated
The use of natural building stone in interior : bachelor thesis
No full textArhitektonsko-građevni ili prirodni kamen u graditeljstvu i arhitekturi ima dugu povijest korištenja prilikom oblaganja unutarnjih i vanjskih dijelova raznih građevina. Najvažnije povijesne i kulturne građevine u Republici Hrvatskoj krasi prirodni kamen iznutra i izvana. Neke od najpoznatijih su grkokatolička konkatedrala sv. Ćirila i Metoda, koncertna dvorana Vatroslava Lisinskog, zgrada Glavnog kolodvora, hotel Sheraton i mnoge druge. Prilikom njegove ugradnje u različite ambijente osim dekorativnog elementa potrebno je i pripaziti na svojstva prirodnog kamena kako bi on bio što dugotrajniji i zadržao svoj izvorni izgled. U završnom radu prikazani su različiti varijeteti prirodnog kamena koji se koriste u interijeru, njihova svojstva te način na koji se treba održavati i čistiti.Natural building stone has been, since long ago, used in construction and architecture in cladding the interior and exterior parts of buildings. Interiors and exteriors of some of the most important historically and culturally significant buildings in the Republic of Croatia are decorated with natural stone. These buildings include the Greek Catholic Co-cathedral of St. Cyril and Methodius, Vatroslav Lisinski Concert Hall, Zagreb Glavni kolodvor building, and Sheraton Zagreb Hotel, just to name a few. In addition to the stone's aesthetic value, natural stone's physical and mechanical properties are also important to preserve its aesthetics and durability. This bachelor thesis presents the different varieties of natural stone used in the interior, their properties, and ways to maintain their appearance
Transport ugljikovog dioksida : završni rad
No full textUgljikov dioksid je staklenički plin koji u velikoj mjeri doprinosi globalnom zagrijavanju Zemlje te su zbog toga razvijene različite metode s ciljem smanjenja emisija ugljikovog dioksida. Jedna od tih metoda je hvatanje i skladištenje ugljikovog dioksida koja obuhvaća hvatanje, transport i trajno skladištenje ugljikovog dioksida. Ugljikov dioksid najčešće se transportira cjevovodima i u tom slučaju je najpoželjnije da ugljikov dioksid bude u superkritičnom stanju. Nakon provedene analize o dizajnu cjevovoda, postojećim standardima, riziku i sigurnosti, vrijednostima tlaka i temperature, rezultati pokazuju da postoje sličnosti između cjevovoda koji transportiraju ugljikov dioksid i cjevovoda koji transportiraju prirodni plin. Ključni problem prilikom transporta ugljikovog dioksida cjevovodima su nečistoće koje mogu utjecati na faznu ravnotežu plina, ali i na pojavu korozije cjevovoda. Uz cjevovode, ugljikov dioksid može se transportirati brodovima pri čemu je ugljikov dioksid visoke kvalitete, odnosno visoke čistoće zato što se koristi u prehrambenoj industriji (npr. karbonizacija pića). Brodovi za transport ugljikovog dioksida nisu razvijeni u tolikoj mjeri kao cjevovodi, ali u Norveškoj su trenutno u izgradnji dva broda koji će u budućnosti transportirati isključivo ugljikov dioksid
Valorizacija značaja različitih mineralnih sirovina u svijetu : završni rad
No full textMineralne sirovine predstavljaju osnovu razvoja industrije i od velike su uporabne i gospodarske vrijednosti. Dok je gospodarska važnost eksploatacije određenih mineralnih sirovina, kao što su energetske mineralne sirovine ili mineralne sirovine metala, jasna i prepoznata u javnosti, važnost pojedinih mineralnih sirovina poput vapnenca, pijeska, šljunka ili građevnog kamena često je marginalizirana. Svaka mineralna sirovina ima određenu industrijsku vrijednost, ali i određeni utjecaj na okoliš, stoga će u ovom radu detaljnije biti prikazan značaj različitih mineralnih sirovina u razvoju suvremenog društva, i to s ekonomskog i ekološkog stajališta
Mineraloška i geokemijska svojstva fluoritne-arsenske mineralizacije Hrmza, Srednje bosanske škriljave planine, Bosna i Hercegovina : završni rad
No full textTerenskim istraživanjima na području potoka Hrmza u Bosni i Hercegovini uočene su pojave fluoritno-arsenske mineralizacije. Makroskopskom i mikroskopskom analizom utvrđeno je da su glavni nositelji fluoritno-arsenske mineralizacije dvije velike formacije: metariolita i metamorfni kompleks Srednjobosanskog škriljavog gorja (sensu Hrvatović, 2022). Metarioliti su pretrpjeli metamorfozu niskog stupnja, prilikom čega su glavni minerali (biotit, feldspati) alterirani, ali prepoznatljivi. Unutar metamorfnog kompleksa stijena domaćina su klasificirani kao nisko metamorfni slejt i filit. Glavni minerali unutar metariolita su kvarc i alkalijski feldspati koji su izrazito trošeni te filosilikati koji su također alterirani, dok su glavni minerali metamorfnih stijena kvarc i filosilikati. Kao akcesorni minerali u metariolitima i u metamornim stijenama javljaju se sericit i klorit, što upućuje na hidrotermalnu aktivnost. Mineralizacija sadrži realgar i auripigment, koji se javljaju unutar milimetarskih do centimetarskih žilica, ili u obliku prevlaka i zemljastih agregata. Fluorit se nalazi unutar žilica i prslina unutar metariolita, gdje se javlja u obliku hipidiomorfnih do alotriomorfnih formi. Geokemijska analiza korištenjem pXRF-a je u skladu s mineraloškom analizom. Unutar metariolita stijene domaćina zabilježene su povišene vrijednosti SiO2 (max. 71,32), Al2O3 i Fe2O3. Unutar niskometamorfnih stijena domaćina također su zabilježene povišene vrijednosti SiO2 (max.78.18), Al2O3 i Fe2O3. XRF analizom u mineraliziranoj zoni utvrđene su povećane koncentracije arsena (do 28,21 mas %), antimona (do 4949,67 ppm-a) i zlata (do 150,67 ppm-a). Fluorit je utvrđen makroskopski, mikroskopski i prijašnjim geokemijskim analizama, te je njegov udio procijenjen na 5-10%
Cenozoic massive carbonate breccia in the External Dinarides of Croatia: the largest outcrop on the island of Krk
No full textThe Cenozoic carbonate breccias in the External Dinarides, known as Jelar deposits or Velebit breccia, have been puzzling geologists for decades. The timing and formation mechanisms of this interesting lithological unit is still debatable. The largest breccia outcrop on the Adriatic islands is located on the southeasternmost part of the island of Krk, on the karstic plateau between Stara Baška and Draga Bašćanska. Approximately 11.5 km long and 350 to 1300 m wide outcrop of a typical Dinaric strike (NW–SE) was studied by detailed geological mapping, structural measurements and sampled along the profile normal to the structure. The breccia outcrops are massive, mostly clast-supported, mostly lacking sedimentary structures. Clasts are unsorted and typically angular, ranging in size from sand to gravel, with rare cobbles and boulders. Clasts are mainly derived from adjacent lithostratigraphic units, many showing calcite-filled fissures, indicating intense tectonics prior to deposition. Clast contacts are commonly characterized by pressure solution, while grey, whitish, yellowish to reddish matrix mostly consists of finely crushed limestone particles or coarse-crystalline calcite grains. Rare small-sized sedimentary bodies rich in matrix with numerous rounded clasts indicate local fluvial transport prior to deposition. Most of the breccia outcrops are located in the hinge zone of the NE-verging overturned anticline (a tectonic transport not common in the Dinarides but typical for all Cenozoic carbonate breccia zones). Along the studied profile, the contacts between breccia and the surrounding rocks are steep but gradual. In most places transition zones from (i) limestones to (ii) tectonized limestones to (iii) cataclastic limestones to (iv) monomict and/ or polymict breccia can be several meters wide. Results of studied breccia outcrop suggest that breccia formation probably onset during the late stage of the principal Late Eocene–Oligocene Dinaric compressional phase by disintegration of source rocks into smallsized clasts. Subsequent localized extension in the hinge of the overturned large-scale anticline created a series of deep canyon-like fractures filled by a large quantity of clasts lithified by mosaic calcite cement
Testing of flexural strength of multi-layered samples of natural stone : master's thesis
No full textČvrstoća pri savijanju bitan je pokazatelj kvalitete prirodnog kamena i važna značajka pri proračunu stabilnosti podzemnih prostorija kamenoloma prirodnog kamena. U ovom radu prikazana je teorija savijanja greda te ponašanja slojevite stijenske mase u krovini podzemnih prostorija prema Obertu i Duvallu. Provedeno je laboratorijsko ispitivanje čvrstoće pri savijanju višeslojnih uzoraka prirodnog kamena „Kanfanar“ sa međusobno različitim međuslojnim uvjetima. Na kraju je provedena analiza rezultata na temelju koje je provjerena ispravnost teorijskih rješenja Oberta i Duvalla za proračun nosivosti krovine podzemnih prostorija kamenoloma prirodnog kamena.The flexural strength is an important indicator of the quality of natural stone and an important feature in calculating the stability of underground rooms of natural stone quarries. This paper presents the theory of beam flexure and the behavior of layered rock mass in the roof of underground rooms according to Obert and Duvall. A laboratory testing of the flexural strength was carried out on multi-layered samples of natural stone „Kanfanar“ with different interlayer conditions. At the end, an analysis of the results was carried out, on the basis of which the useability of the theoretical solutions of Obert and Duvall for calculating the stability of underground rooms of the natural stone quarry was verified
Influence of load increment ratio on soil consolidation properties : master's thesis
No full textCilj ovog rada bio je ispitati utjecaj veličine inkrementa naprezanja na konsolidacijska svojstva tla. U tu svrhu provedeno je laboratorijsko ispitivanje jednodimenzionalne konsolidacije u klasičnom edometarskom uređaju. Prikazani su temeljni principi teorije jednodimenzionalne konsolidacije te interpretacija parametara koji se koriste u procjeni slijeganja. Ispitivanje tla je provedeno na dva uzorka s različitim rasporedom opterećenja. Jedan uzorak opterećen je u inkrementima koji su definirani u normi i uobičajeno se primjenjuju u praksi, a drugi je opterećen ciklusom s manjim inkrementima. Opažano je kakav će to utjecaj imati na parametre stišljivosti i konsolidacijska svojstva tla. Indeks kompresije i rekompresije, kao i naprezanje prethodne konsolidacije nisu se značajnije razlikovali. Međutim, kod analize dijagrama vremenskog tijeka slijeganja, za uzorak s malim inkrementima, krivulje konsolidacije su odstupale od teorijskih zbog čega interpretacija koeficijenta konsolidacije nije bila moguća. U nekoliko drugih studija o sličnoj problematici pokazalo se da veličina inkrementa naprezanja značajno utječe na komponente ukupnog slijeganja zbog čega krivulja gubi karakterističan oblik. Zaključeno je kako ispitivanje s malim inkrementima može biti praktično za preciznije određivanje naprezanja prethodne konsolidacije i parametara stišljivosti, ali može onemogućiti interpretaciju vremenskog tijeka slijeganja.The aim of this study was to investigate the influence of the load increment ratio on the soil consolidation properties. For this purpose, a laboratory test of one-dimensional consolidation was carried out using a conventional oedometer. In this work, the fundamental principles of the one-dimensional consolidation theory were presented and the parameters used for the settlement calculation were defined. Two soil samples were subjected to a constant total axial stress with different load increment ratios. One test was carried out with the standard loading sequence commonly used in practise, the other with an alternative loading scheme consisting of small load increments. The effects on the consolidation behaviour of the soil were investigated by observing the compressibility parameters and the consolidation properties. The results for the compression index, swell index and pre-consolidation pressure showed no significant differences. However, in the tests with alternative loading sequence, the time–displacement curves show a different shape than the one based on the onedimensional consolidation theory. For this reason, it was not possible to correctly estimate the coefficient of consolidation. Several other studies have shown that the magnitude of the load increment ratio strongly influences the shape of the time–displacement curve, which can be explained by the change in the primary consolidation ratio of the total settlement. It was concluded that although small increments are desirable to determine the preconsolidation stress and compressibility parameters with greater accuracy, they may hinder the evaluation of the coefficient of consolidation and time settlement interpretation
Regulatory and strategic framework for biogas and biomethane injection into European Union transportation systems : master's thesis
No full textU diplomskom radu dan je pregled stanja tržišta bioplina i biometana u Europskoj uniji, fokusirajući se na pitanja kao što su: trenutna i buduća ponuda i potražnja za bioplinom i biometanom te važeći zakonski, regulatorni i politički okviri i sustavi financijskih potpora koji se koriste u EU zemljama. Napravljena je usporedba i analiza odnosa između razvoja bioplina i biometana i nacionalnih političkih okvira u šest europskih zemalja. Svrha ovog rada je sveobuhvatna procjena uvjeta i mogućnosti za razvoj sektora bioplina i biometana u EU uz trenutno važeće zakone, regulative i instrumente politike s naglaskom na uvjete umješavanja bioplina i biometana u postojeće transportne sustave prirodnog plina. Prilikom istraživanja uzet je u obzir regulatorni i politički okvir za proizvodnju, transport i distribuciju bioplina i biometana, tržišna situacija (uključujući potencijal potražnje i ponude) te sustavi podrške proizvođačima.This thesis provides an overview of the state of the biogas and biomethane market in the European Union, focusing on issues such as current and future supply and demand for biogas and biomethane and the current legal, regulatory and policy frameworks and financial support systems used in EU countries. A comparison and analysis of the relationship between the development of biogas and biomethane and national political frameworks in six European countries was made. The purpose of this thesis is a comprehensive assessment of the conditions and opportunities for the development of the biogas and biomethane sector in the EU under currently valid laws, regulations, and policy instruments with an emphasis on the conditions for mixing biogas and biomethane into the existing natural gas transport systems. During the research, the regulatory and political framework for the production, transportation and distribution of biogas and biomethane, the market situation (including potential demand and supply), and support systems for producers were taken into account
Analysis of repair works in a ten-year period on the example of an oil and gas field in the Republic of Croatia : master's thesis
No full textU ovom diplomskom radu napravljena je analiza remontnih radova u periodu od 2011. godine do 2022. godine na primjeru jednog naftno plinskog polja u Republici Hrvatskoj. U radu su opisane metode pridobivanja kapljevine na razmatranom polju te su opisani dijelovi proizvodne opreme koji se koriste za pojedine metode pridobivanja kapljevine. Polja koja su prestala eruptivno proizvoditi vlastitom energijom iz ležišta, proizvode i dalje ali uz primjenu mehaničke metode pridobivanja kapljevine. Najstarija mehanička metoda pridobivanja kapljevine je dubinska klipna sisaljka s klipnim šipkama. Uz tu metodu na ovom naftno plinskom polju koriste se i centrifugalne sisaljke. Samo na pojedinim bušotinama sisaljke s klipnim šipkama zamijenjene su sa linearnim sustavom podizanja kapljevine, ovaj sustav u cjelini je puno bolji jer troši manje električne energije i radi u više različitih frekvencija koje se reguliraju preko kompjutera. Na temelju prikupljenih podataka provedena je analiza kolika količina fluida nije proizvede na tijekom čekanja na remont opreme i za vrijeme samog remonta, koliko se vremena čekalo i koliko je trajao remont opreme te je procijenjena isplativost remonta.This thesis presents an analysis of repair works in the period from 2011 to 2022 on the example of an oil and gas field in the Republic of Croatia. The thesis describes the methods of fluid extraction in the considered field and provides an overview of the components of production equipment used for each method of fluid extraction. Fields that have ceased to produce fluid naturally from reservoirs continue to p roduce using mechanical methods of fluid extraction. The oldest mechanical method of fluid extract ion is the deep piston pump with piston rods. In addition to this method, centrifugal pumps are also used in this oil and gas field. Only in certain wells, piston pumps have been replaced with a linear fluid lifting system, which is overall more efficient as it consumes less electrical energy and operates at various frequencies regulated by a computer. Based on the collected data, an analysis was conducted to determine the amount of fluid not produced during equipment maintenance and repair, the waiting time for repairs, the duration of equipment maintenance, and the cost effectiveness of the repairs