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Anticorrosion and antibacterial properties of Al NP–epoxy nanocomposite coating on grey cast iron
No full textIn this study, different concentrations of aluminium nanoparticles (Al NP) were incorporated into epoxy resin and epoxy paint. Here, we present a detailed systematic study of different methods of incorporating inorganic nanoparticles into epoxy coating. This work aims to obtain an epoxy coating with anticorrosion and antibacterial properties. The physical properties of coatings such as thickness, hardness, colour, and adhesion did not change with the addition of nanoparticles. According to the SEM and EDS analyses, the distribution effect of Al NPs in epoxy coating was better with ultrasonic homogenisation than with mechanical stirring. The EIS and SECM measurements were used to investigate corrosion resistance. The coating with 1.0 wt.% Al NP showed the best physical and chemical properties. SECM examination indicated that nanoparticles in epoxy resin increase the protection efficiency by 25.75% and in the epoxy paint by 40.89%. The results also showed the antibacterial activity of aluminium nanoparticles by inhibiting the growth of biofilm-forming bacteria such as P. aeruginosa and B. subtilis
Izvješće Hrvatskog odbora za geodeziju i geofiziku o provedenim aktivnostima od 2019. do 2022. - podneseno Generalnoj skupštini Međunarodne unije za geodeziju i geofiziku, Berlin, Njemačka, 2023.
No full textSadržaj:
Uvod
Geodezija u Hrvatskoj, 2019.–2022
Geomagnetizam i aeronomija u Hrvatskoj, 2019.–2022
Hidrologija i fizikalna limnologija u Hrvatskoj, 2019.–2022
Meteorologija u Hrvatskoj, 2019.–2022
Fizička oceanografija u Hrvatskoj, 2019.–2022
Seizmologija u Hrvatskoj, 2019.–2022Content:
Introduction
Geodesy in Croatia, 2019–2022
Geomagnetism and aeronomy in Croatia, 2019–2022
Hydrology and physical limnology in Croatia, 2019–2022
Meteorology in Croatia, 2019–2022
Physical oceanography in Croatia, 2019–2022
Seismology in Croatia, 2019–202
Optimization of mining works for the purpose of obtaining and installing the dimension stone of a uniform appearance
No full textLežišta arhitektonsko-građevnog kamena (u nastavku: a-gk) uglavnom su heterogenog sastava i neujednačenih svojstava. U svrhu istraživanja ležišta a-gk potrebno je izvesti određene rudarske radove kako bi se prikupili podaci za utvrđivanje: postojanja, položaja i oblika ležišta, količine i kakvoće, te uvjeta eksploatacije a-gk. Položaj i oblik ležišta imaju presudan utjecaj na uvjete eksploatacije a-gk, Kao posljedica dinamičkih i kemijskih procesa u stijenama su nastali diskontinuiteti različitih položaja, dimenzija i oblika. Eksploatacija a-gk iz ležišta izvodi se dobivanjem što je moguće geometrijski pravilnijih i, po dimenzijama, većih blokova. Eksploataciju a-gk potrebno je uskladiti s položajem i oblikom ležišta kao i diskontinuitetima u svrhu dobivanja što većeg iskorištenja stijene. Međutim, poseban zahtjev građenja predstavlja dobivanje a-gk, prvenstveno, ujednačenog izgleda i drugih svojstava. Stoga je nužno optimizirati rudarske radove u svrhu dobivanja i ugradnje a-gk ujednačenog izgleda, što je opisano i prikazano na nekoliko primjera u ovom radu.Deposits of dimension stone (hereinafter: DS) are mostly of heterogeneous composition and non-uniform properties. For the purpose of exploring the DS deposit, it is necessary to perform certain mining work in order to collect data for the determination of: existence, position and shape of the bed, quantity and quality, and the conditions for exploitation of DS. The position and shape of the deposit have a crucial influence on DS exploitation conditions. Discontinuities of different positions, dimensions and shapes were formed as a result of dynamic and chemical processes in the rocks. The exploitation of DS from the deposit is performed by obtaining as geometrically regular and as large in size blocks as possible. The DS exploitation should be harmonized with the position and shape of the deposit as well as discontinuities for the purpose of obtaining the highest possible exploitation of stone. However, a special requirement of construction is to obtain the DS, primarily of uniform appearance and other properties. Therefore, it is necessary to optimize mining works for the purpose of obtaining and installing DS of a uniform appearance, as described and shown on several examples in this paper
Development of investigation programme for biochar intended for underground carbon storage : master's thesis
No full textUnutar diplomskog rada obrađen je razvojni program istraživanja biougljena s namijenom skladištenja ugljika u podzemlje. Dani je istražni program biougljena koji se temelji na pregledu Pravilnika o odlagalištima otpada, Europskom certifikatu za biougljen i Pravilniku o gospodarenju otpadom. Provedena su ispitivanja u Centralno kemijsko-tehnološkom laboratoriju HEP-Proizvodnje d.o.o. s ciljem usporedbe sastava kamenog ugljena i biougljena. Na temelju dobivenih podataka predložena su sljedeća ispitivanja zajedno s normama na temelju kojih se dobivaju podaci o utjecaju biougljena na atmosferu u kojoj bi se skladištio.Within the diploma thesis, the development program of biochar research with the purpose of carbon storage in the underground was processed. An investigation program for biochar was given, which is based on a review of the Ordinance on waste disposal sites, the European certificate for biochar and the Ordinance on waste management. The tests were carried out in the Central Chemical and Technological Laboratory of HEP-Proizvodnja d.o.o. with the aim of comparing the composition of hard coal and biochar. Based on the obtained data, the following tests were proposed together with the norms based on which data on the impact of biochar on the atmosphere are obtained
Impact of mechanical stratigraphy on deformation style and distribution of seismicity in the central External Dinarides: a 2D forward kinematic modelling study
No full textAbstract The External Dinarides fold-thrust belt formed during Mid-Eocene–Oligocene times by SW-propagating thrusting from the Internal Dinarides towards the Adriatic foreland. Although previously considered as structurally quite uniform, recent work reported along-strike contrasting deformation styles in two structural domains within this fold-thrust belt. The two areas with very contrasting deformation styles are separated by the N–S-striking dextral Split-Karlovac Fault, a 250 km long, transpressive transfer fault. The southeastern domain is characterized by a thin-skinned SW-vergent nappe stack in contrast to the northwestern domain, where a set of blind, thick-skinned top-SW thrust duplexes prevail underneath the passive NE-vergent backthrusts. To better understand why the External Dinarides underwent such contrasting along-strike deformation, we reconsidered a temporal and spatial along- and across-strike distribution of Paleo-Mesozoic lithofacies to both sides of the Split-Karlovac Fault and estimated the role of mechanical stratigraphy on deformation styles in this part of the fold-thrust belt. Therefore, we constructed a new 2D kinematic forward model in the western backthrust-dominated domain. Our best-fit forward-modelled balanced cross section across the central Velebit Mtn. portrays a 75 km wide triangle zone. This zone took up at least 47 km of shortening during Eo-Oligocene times. It comprises a set of thin-skinned NE-vergent backthrusts detached in the upper Paleozoic atop a SW-vergent thick-skinned antiformal stack detached in the lower Paleozoic Adriatic basement. The NE-vergent backthrusts likely nucleated at lateral facies boundaries related to extensional half grabens that locally formed during Middle Triassic and Late Jurassic passive margin extension. During the Eo-Oligocene folding and thrusting, the selective inversion of inherited Mesozoic half grabens boundary faults into the NE-vergent backthrusts in the northwestern domain led to the observed along-strike changes in the deformation style of the External Dinarides. A seismotectonic analysis of instrumentally recorded earthquakes suggests contrasting seismic behaviour along the central and southern Velebit transects within the northwestern structural domain. The central Velebit Mtn. triangle structure appears to currently accommodate dominantly strike-slip motion, with reverse faulting being confined to east of the Split-Karlovac Fault. In contrast, seismicity along the southern Velebit cross section appears to be confined to the structurally lowermost parts of the triangle zone and the foreland, while it´s structurally higher parts are less seismically active. Also, a predominance of reverse faulting along this transect suggests ongoing accommodation of shortening in this part. Our results indicate that both the variations in the mechanical stratigraphy and the pre-orogenic structural inheritance obtained during rifting and passive margin stages exert control on contractional structures within the External Dinarides, including the distribution of present-day seismicity
Adapted Schmidt hardness testing on large rock samples—Kanfanar-South Quarry case study
No full textThis paper deals with the possibility of using the Schmidt hardness test, which does not require much preliminary preparation and is easy to perform, in the production of commercial blocks in a quarry. Previous recommendations for Schmidt hardness testing of rock materials were specifically related to tests performed for geomechanical purposes. They also referred mostly to smaller samples, but testing of commercial blocks has some special features, mainly because they are large samples for which practically larger areas must be tested. This paper presents the testing methodology in terms of the number and position of hammer strikes on a commercial block, as well as the application of corrections to the test results in terms of the way the blocks are cut. The tests were conducted on natural stone blocks from the Kanfanar-South quarry, which is characterized by limestone rocks. The test results show that the test methodology can be applied in quarries with similar geological structure and natural stone mining methodology
Fractal characterization of multiscale fracture network distribution in dolomites : outcrop analogue of subsurface reservoirs
No full textFractured aquifers, especially dolomites, are important hydrocarbon reservoirs and sources of thermal and groundwater in many parts of the world, especially in the Alpine-Dinaric-Carpathian region. The most dominant porosity type is fracture porosity, which acts as the preferential fluid pathway in the subsurface, thus strongly controlling fluid flow. Outcrops provide valuable information for the characterization of fracture networks. Dolomite rock properties and structural and diagenetic processes result in fractured systems that can be considered fractals. The fracture network was analyzed on 14 vertical outcrops in 35 digitized photographs. The values of the fractal dimensions varied slightly by the software and method used, but the trends were consistent, which confirms that all methods are valid. Small values of fractal dimension indicate the dominance of a few small or large fractures, and high values of fractal dimension result from a combination of large numbers of small fractures accompanied by a few large fractures. The mean value of the fractal dimension for analyzed fracture networks was 1.648. The results indicate that the fracture network of the Upper Triassic dolomites can be approximated by fractal distribution and can be considered a natural fractal, and values can be extrapolated to higher and lower scales (1D and 3D)
Modelling cover-collapse sinkholes that appeared after the M6.2 Petrinja earthquake in Croatia using electrical resistivity tomography data
No full textAfter the destructive earthquake in Petrinja measuring M6.2 occurred on 29 December 2020, which was followed by a series of foreshocks and aftershocks in the area of the rural settlements in Mečenčani and Borojevići, cover-collapse sinkholes suddenly appeared. The investigated area is located 20 km southeast of the epicentre. Some months later, more than 90 cover-collapse sinkholes appeared, jeopardising local infrastructure and residential buildings. The sinkholes appear in the area of covered karst, where there are clastic deposits 2–10 m thick on the fractured and weathered limestone bedrock. There are two geological models located in the investigated area: GM-1, where the base consists of clastic strata covering comprising Lithothamnium limestone, which in turn leads to the formation of underground cavities and cover-collapse sinkholes, and the GM-2, where the base comprises clay deposits without any cover-collapse sinkholes. These models can be effectively distinguished due to tomographic resistivity models; hence, numerous measurements were undertaken using two-dimensional electrical tomography in several phases. An estimate of the threat to infrastructural facilities was conducted, and the boundaries of the geological models were precisely determined according to which underground cavities and cover-collapse sinkholes did not develop. Tomographic measurements were also conducted over the largest cover-collapse sinkhole measuring 25 m in diameter and helped to more precisely define the entire hydrogeological model and the mechanisms involved in the formation of cover-collapse sinkholes
Curriculum development for improving mineral exploration-related master programs towards innovation, entrepreneurship and social responsibility
No full textNordic and West Balkan countries are major investment regions in Europe for greenfield and brownfield mineral exploration; however, the availability of qualified technical, scientific and managerial personnel involved in the whole mineral cycle is limited, especially in West Balkan countries. The partners of the TIMREX EIT RawMaterials-labeled MSc program have developed a joint curriculum focused on innovative raw materials prospecting and exploration methods, with strong innovation and entrepreneurial components. The program incorporates new exploration techniques and methodologies, portable and more highly sensitive equipment, robotized exploration equipment and the processing and interpreting of large, multidimensional datasets. The TIMREX curriculum was built around the ideal mineral exploration program, as suggested by raw materials stakeholders and orientated to field geology, exploration techniques and data processing, and also includes elements of sustainability, transversal societal and regulatory aspects. The program also focuses on EIT Overarching Learning Outcomes (OLO-s), which are embedded as core elements of the curriculum (innovation, entrepreneurship, sustainability, creativity, leadership and intercultural competencies). Significant contributions to the OLOs also arise from cross-organizational program elements, including the Exploration Entrepreneurship course, summer field camp, the Internship and the Social and Civic internship