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Evidence of Late Quaternary environmental changes preserved within the Privlaka pedo-sedimentary complex at the eastern Adriatic coast, Croatia
No full textThe Privlaka pedo-sedimentary succession (Eastern Adriatic coast, Croatia) is a promising archive of palaeoenvironmental changes as it shows a clear alternation of (a) palaeosol(s) and glacio-fluvial deposits. The objective of this study is to describe the palaeosols and sediments, and unravel the nature, magnitude and timing of environmental change preserved within this terrestrial record. To this end, a more than 12 m thick section was investigated in detail, which is divided into four different units of which one is represented by a reddish palaeosol, and the other three by sediment packages, each indicating a different pedosedimentological context. For the purpose of delineating the absolute thickness and lateral extent of the complex, geoelectrical soundings and remote sensing techniques were deployed. The profile was thoroughly described and sampled for the purpose of conducting high-resolution palaeoenvironmental research using mineralogical, geochemical, pedophysical and micromorphological properties. Preliminary results will be presented and discussed in the light of the Late Quaternary palaeoenvironmental evolution of the region and surroundings. The research is funded by the Croatian Science Foundation under the projects ACCENT (IP-2020-02-3274) and DOK-2021-02-9476
Nitrification and denitrification in the wastewater treatment process : master's thesis
No full textOsnovni cilj diplomskog rada je istraživanje bioloških metoda pročišćavanja otpadnih voda, nastalih prilikom prodora oborinskih voda ili tijekom procesa biorazgradnje otpada sa odlagališta Jakuševac. U svrhu ispitivanja kakvoće otpadnih voda, provedene su analize i mjerenja nekoliko ključnih parametara: biološka potrošnja kisika (BPK), kemijska potrošnja kisika (KPK), masene koncentracije nitrata, nitrita i amonijevog kationa te pH vrijednost otpadnih voda. Poseban naglasak dan je na procese nitrifikacije i denitrifikacije, odnosno proučavanje utjecaja koncentracije aktivnog mulja na brzinu nitrifikacije te određivanje optimalnog volumena etanola koji je potreban za potpunu denitrifikaciju. Zaključuje se da je smanjenjem količine aktivnog mulja, smanjena i brzina nitrifikacije, a porastom temperature, povećava se i brzina denitrifikacije. Proces denitrifikacije postiže potpuno uklanjanje nitrata i nitrita iz sustava uz upotrebu dodatka suviška etanola, što rezultira koncentracijama nitrata i nitrita koje su u skladu sa zakonskom regulativom.The main objective of this graduate thesis is to investigate biological methods for purifying wastewater generated during the infiltration of rainwater or the waste biodegradation process at the Jakuševac landfill. In order to assess the quality of wastewater, analyses and measurements of several key parameters were conducted: biological oxygen demand (BOD), chemical oxygen demand (COD), mass concentrations of nitrates, nitrites, and ammonium ions, as well as the pH value of the wastewater. Special emphasis was placed on the processes of nitrification and denitrification, including studying the influence of activated sludge concentration on nitrification rate and determining the optimal volume of ethanol required for complete denitrification. It is concluded that reducing the amount of activated sludge reduces the nitrification rate, while increasing temperature also increases the denitrification rate. The denitrification process achieves the complete removal of nitrates and nitrites from the system with the addition of an excess of ethanol, resulting in nitrate and nitrite concentrations that comply with legal regulations
Topljivost soli : završni rad
No full textU geološkom smislu voda na svom putu po Zemljinoj kori i kroz Zemljinu koru, od kišnice pa do mora, prolazi kroz mnoge petrografski i kemijski različite slojeve i stijene. U kontaktu s njima se zbivaju različite reakcije, voda otapa jedne, a taloži druge minerale. U ovom radu dan je pregled fizikalno-kemijskih i termodinamičkih parametra koji utječu na proces otapanja soli
Utjecaj nečistoća u kaptiranom CO2 na elemente CCS-a : završni rad
No full textU radu je analizirana važnost sastava CO2 plina u kontekstu njegovog transporta i skladištenja. Primjese koje se uz CO2 nalaze u kaptiranom CO2, u odnosu na čisti CO2, različito utječu na pad tlaka u cjevovodu, što treba uzeti u obzir kako bi se izbjegli uvjeti protjecanja koji mogu dovesti do problema kao što su korozija i zaostajanje kapljevine. Nakon određivanja PVT svojstava kubičnom jednadžbom stanja (korištenjem komercijalnog PVT simulatora), izračunat je pad tlaka za čisti CO2 i sastav CO2 toka koji bi se očekivao nakon hvatanja u tvornici cementa oxyfuel tehnologijom. Pokazano je kako sukcesivan proračun u malim segmentima pruža preciznije rezultate od proračuna za cijelu duljinu cjevovoda odjednom, posebno uzimajući u obzir promjene gustoće i viskoznosti fluida. Pri ovakvom proračunu, bitno je izraditi bazu podataka o odnosu tlakova, temperature, gustoća i viskoznosti za svaki specifičan sastav CO2 kako bi se dobili točni rezultati. Eksperimentalno dobivanje PVT podataka ključno je za pravilno modificiranje jednadžbe stanja i postizanje još boljih rezultata u analizi transporta CO2 s nečistoćama
Određivanje karakteristike ventilatora u rudniku Tehničkog muzeja Nikola Tesla : završni rad
No full textU ovom radu prikazano je određivanje karakteristike ventilatora u rudniku Tehničkog muzeja Nikola Tesla. Izmjerene su vrijednosti pada tlaka na ventilatoru i protoka zraka u vjetrenom hodniku pri šest različitih položaja vjetrenih vrata na pet različitih brzina rotacije lopatica ventilatora. U rezultatima je prikazana karakteristika ventilatora u različitim režimima rada
Sedimentological evidence of climatic changes during the Miocene Climatic Optimum in the North Croatian Basin (SW Pannonian Basin System, Croatia)
No full textThe North Croatian Basin (NCB) occupies the south-western part of the Pannonian Basin System, and belongs to the Central Paratethys realm. Detailed sedimentological field studies and mineralogical and petrological analyses showed that a 40 m thick section composed of well-bedded mixed, carbonate–siliciclastic deposits with occurrence of pyroclastics indicate three evolutional stages of lake development. The first evolutionary stage evolved in the late Early Miocene. It was characterised by mainly dolomite precipitation directly from the water body, and are associated with tuffites and marls, together with minerals such as analcime, hydrous Ca-bearing magnesium carbonate, and natrolite. This indicates deposition in a shallow, hydrologically closed lake of highly alkaline waters controlled by an arid climate. The second evolutionary stage is represented by the intercalation of dolomites and sandstones, indicating changes of hydrologically open and closed lacustrine environments as result of the frequent alternation arid and humid climates. The third stage, characterized by deposition of siliciclastics by gravity flows indicates the formation of a long-lived, hydrologically open lake that probably commenced in the Middle Miocene. The whole investigated lacustrine depositional sequence coincides with the Miocene Climatic Optimum generally characterized by hot and warm, and humid climates. However, the evolution of the closed lake that is correlative with similar lakes in northern Bosnia and central Serbia, indicates the existence of an arid zone in the region that was confined by areas characterized by a more humid climate in the late Early Miocene
Plankton stratigraphy provides a mid-Paleogene age constraint for the Dalmatian Flysch in External Dinarides foreland basin
No full textFlysch marks the synorogenic deposition in external foreland fold-and-thrust belts (FATB) around the globe. Thus, a precise estimation of its stratigraphic range is crucial for reconstructing the orogenic histories in these belts. Dinarides FATB is a young orogen settled between the Alps and the Hellenides in SE Europe originating from the NE-wards subduction of the Adriatic plate under the Eurasia. The youngest onshore flysch deposits termed the Dalmatian Flysch mark the position of the External Dinarides foreland basin (EDFB) stretching both over its interior High Karst as well as its exterior Dalmatian tectonic unit. There is an ongoing discussion on its stratigraphic context, contrasting a Paleogene with a Neogene age. Such a difference in age estimation provides severe uncertainties for the reconstruction of tectonic and paleogeographic constrains. In particular, the Neogene age of the Dalmatian Flysch would imply the coexistence of contractional and extensional tectonics in the Miocene of External Dinarides; the latter marked by establishment of numerous intramountain basins encompassing a long lasting lacustrine environment of the so-called Dinarides Lake System. To test the hypothesis on such coexistence, 76 sediment bulk-samples have been collected from 31 sites of the Dalmatian Flysch referred to by current literature as Miocene. They are distributed along a 400-km-long axial transect of the EDFB in Croatia, Bosnia–Herzegovina, and Montenegro between cities of Pag in the NW and Ulcinj in the SE. In contrast to previous studies, we use the calcareous plankton stratigraphy integrating nannoplankton and foraminifera records. Our preliminary results detected neither the presence of Miocene, nor of Oligocene assemblages in the samples. This result is supported by the occurrence of well-preserved planktonic foraminifera including the Middle to Late Eocene stratigraphic markers Globigerinatheka barri, Hantkenina compressa, and Morozovelloides crassatus. The corresponding stratigraphic interval is corroborated by the calcareous nannoplankton assemblages comprising index species such as Sphenolithus furcatolithoides, Cribrocentrum reticulatum, C. erbae, and Furcatolithus obtusus. Accordingly, the present data prove a marine offshore deposition in the EDFB during the Oligocene and the Miocene improbable
Deposition of volcaniclastites in pelagic environment on rifted continental margin during the Middle Triassic
No full textThe Middle Triassic volcano-sedimentary successions related to the opening of the Neotethys Ocean in NW Croatia were investigated for their age and facies interpretation. Stratigraphically stacked volcanic and volcaniclastic lithologies, ranging from basaltic to rhyolitic, are interlayered with pelagic sedimentary rocks in the studied sections. These successions were deposited on a passive continental margin with dynamics set by intense rift-related tectonic movements and volcanic activity. Following disintegration of stable shallow-marine environment newly formed lithospheric blocks gave rise to a complex pelagic depositional environment as extension progressed. Pelagic limestones and radiolarian cherts were deposited on drowned blocks with episodic intercalations of volcanic and pyroclastic deposits from the early Illyrian to possibly late Ladinian. Shallow-water carbonate environment still existed laterally as suggested by resedimented carbonate detritus. Deep-rooted normal faults created by extension provided paths for submarine basaltic extrusions. Magma quenched in contact with sea water creating basaltic hyaloclastites that were redeposited in deeper parts of the basin. Acidic volcaniclastics, commonly known as “pietra verde”, were produced by explosive volcanic eruptions, and deposited in pelagic environment by different gravitational mechanisms, including pyroclastic density currents. Variations in thickness of these deposits indicate different sedimentation mechanisms and reflect complex topography of the depositional environment. Water-settled air fall deposits produced thinner layers, while thicker layers indicate redeposition of material from topographic heights to more subsided parts. Unconsolidated pyroclastic detritus was partly reworked soon after deposition and redistributed gradually filing the basin. Medium- to fine-grade turbidite sedimentation is inferred for these deposits based on grain size, normal grading, horizontal lamination and mixing of volcanic and pelagic material. Presumed stratigraphic gaps in investigated successions, and possibly condensed sedimentation, can be explained by complex basin topography and prevailing sedimentation mechanisms, which resulted with sediment erosion and its subsequent redistribution
Restricted to open-marine Middle Triassic basins of the Dinarides and their radiolarian faunas
No full textLate Anisian rifting resulted in a complex horst-and-graben paleotopography of the Adriatic continental margin. The most deeply subsided basins (e.g. Budva, Bosnian and Slovenian basins) remained sites of pelagic sedimentation until the latest Cretaceous. Shallower basins formed on structural highs, which were internally differentiated into several fault blocks. These shallow basins were short lived, limited to the interval between the Late Anisian to Ladinian or earliest Carnian, when they were completely filled in so that sedimentation of platform carbonates was again established in a wider area. The High Karst Zone in the External Dinarides preserves two types of sequences from this short pelagic episode. Both are characterized by micritic limestone and chert, generally include pyroclastic rocks (Pietra Verde), and locally contain carbonate breccia and calcarenite. The most obvious difference is the color of the rocks. The successions in the center of the High Karst Zone are dark grey to black due to the presence of organic matter, which may have been related to stratified water column and/or poor open-marine connections in a restricted intra-platform basin. In contrast, the pelagic limestone and chert at the margins of the High Karst swell are light to vivid red, in places greenish or light grey to pink. This latter lithology is comparable with the Buchenstein Formation of the Southern Alps. We investigated radiolarians from several Buchenstein type sections and from one organic-matter-rich section located at Mt. Svilaja in Dalmatia. The radiolarian assemblages of the Buchenstein type sections contain up to 80 genera and include multicyrtid nassellarians that are generally regarded as deeper-dwelling morphotypes and are also common in the sedimentary cover of Triassic ophiolites. The radiolarian assemblage of Mt. Svilaja consists of only 20 genera. Spumellarians and entactinarians are abundant but nassellarians account for only 5% and are represented exclusively by monocyrtids. A similar assemblage was described from the San Giorgio Dolomite in the westernmost part of the Southern Alps. Such impoverished assemblages with high predominance of surface-dwelling taxa are apparently characteristic of restricted oxygen-deficient basins that were separated from the open ocean by topographic barriers
The transmission of detonation of ANFO explosives : master's thesis
No full textANFO eksplozivi u najvećoj se mjeri koriste za površinska miniranja u Republici Hrvatskoj. Razlog tomu je relativno niska nabavna cijena, jednostavnost proizvodnje, sigurnost pri rukovanju, zadovoljavajući učinci miniranja te mogućnost mehaničkog punjenja bušotina. Unatoč čestoj uporabi, postoji nedostatak znanja u postizanju optimalnih parametara detonacije. U ovom radu provedeno je istraživanje s ciljem određivanja prijenosa detonacije ANFO eksploziva kao jednog od važnih detonacijskih parametara eksploziva. Kako bi se odredio prijenos detonacije ANFO eksploziva provedena su terenska ispitivanja na poligonu za ispitivanje eksplozivnih tvari. Ispitivanje je provedeno prema zahtjevima norme HRN EN 13631-11:2004: Eksplozivi za civilnu uporabu. Jaki eksplozivi. 11. dio: Određivanje prijenosa detonacije (EN 13631-11:2003).ANFO explosives are mostly used for surface blasting in the Republic of Croatia. The reason for this is the relatively low purchase price, ease of production, safe handling, satisfactory blasting effects and the possibility of mechanical filling of boreholes. Despite frequent use, there is a lack of knowledge in achieving optimal detonation parameters. In this paper, research was conducted with the aim of determination of transmission of detonation of ANFO explosives as one of the important detonation parameters of explosives. To determine the transmission of detonation of ANFO explosives, field tests were conducted at the testing ground for explosive substances. The test was carried out according to the requirements of HRN EN 13631-11:2004: Explosives for civil uses. High explosives. Part 11: Determination of transmission of detonation (EN 13631-11:2003)