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Evaluation of input parameters for the non-ideal detonation model of emulsion explosives
No full textEmulsion explosives exhibit non-ideal detonation behaviour. The degree of their nonideality depends mostly on their composition and density (i.e., porosity), which in turn is a function of amount of glass-microspheres added. Variation in composition results in a significant difference in the detonation properties. This presents an additional difficulty for numerical modelling of detonation of emulsion explosives since the input parameters for the modeling (such are reaction rate, equation of state of unreacted explosive, etc.) differ for each composition and density. In this paper we present the results of calibration of the constants in pressure-dependent rate model incorporate in the Wood-Kirkwood detonation model. The constants are determined for several low-density emulsion explosives which contain up to 50% glass micro-balloons, in such a way that they reproduce the experimental detonation velocitiescharge diameters data. It was shown that pressure-dependent reaction rate model and the rate constants obtained in this study, can satisfactorily reproduce experimental detonation velocity-charge diameter for unconfined charges having densities in the range 0.5 to 1 g/cm3
Relation between air and soil pollution based on statistical analysis and interpolation of Nickel (Ni) and Lead (Pb): Case study of Zagreb, Croatia
No full textPurpose. This paper focuses on the comparison of Ni and Pb concentrations in air and soil pollution in the Zagreb area. Due to the very limited amount of publicly available data from soil analysis samples, 2016 and 2019 were chosen as the best possible indicators of related changes in metal concentrations in soil and air. Methods. Testing the normality of Ni and Pb concentrations in the total deposited matter (TDM) confirmed the feasibility of using two parametric statistical tools – the Pearson correlation coefficient and the t-test. The Inverse Distance Weighting (IDW) interpolation method was selected as the best approach for a small number of measurements. Findings. The insufficient amount of data is the main shortcoming for urban health policy in a large area like Zagreb. The small number of air measurement stations and especially soil sampling sites cannot lead to any reliable conclusions about urban pollutants, their activity over time and direct links to soil toxic degradation based on statistical or geological methods and analyses. However, there is no doubt that urban pollution sources fill the soil with accumulated toxic elements such as Ni and Pb, especially in suburban areas located along the paths of the dominant wind directions. Originality. This is an original research that for the first time statistically analyzes and maps publicly available air and soil pollution data for the period 2016-2019. Practical implications. This research is a necessary step in determining the future planning of air and soil measurement stations in the Zagreb urban area
Sedimentological characteristics of the Aptian–Albian deposits of the Kanfanar quarry, Istria
No full textU kamenolomu Kanfanar, u blizini istoimenog mjesta u zapadnom dijelu središnje Istre, izvrsno je otkriven istraženi dio aptsko–albskih naslaga s nekoliko emerzijskih površina, tj. diskordancija. Najznačajnija diskordancija predstavlja regionalnu emerziju i granicu između 2. i 3. megasekvencije naslaga Istre (TIŠLJAR et al., 2002). U okviru terenskog rada i istraživanja na području kamenoloma Kanfanar snimljen je, uzorkovan i opisan slijed naslaga debljine 20,85 m (slika 1). Na temelju mikroskopskih litoloških značajki i fosilnog sadržaja određena su četiri mikrofacijesa (MF1–MF4). Mikrofacithat fact, this landslide density map harmonizes historical landslide records on the national level and allows a quantitative measure of landslide spatial distribution which enables direct comparison of different regions. According to the analyses the zones with the highest landslide density are distinguished in areas around the cities of Virovitica, Krapina, Kravarsko, Zagreb, Samobor, and Požega. Still, it is important to point out that this map cannot provide estimates of landslide occurrences in the future. Therefore, this inventory and landslide density will be further used to estimate the geological units most susceptible to landslides and assess their geomorphological characteristics, which strongly influence landslide occurrence. jes MF1 obuhvaća mikritne vapnence (vekstone-pekstone) s bačinelama, dekastronemama, bentičkim foraminiferama, bioklastima, onkoidima i fragmentima školjkaša (većinom rudista) te ukazuje na okoliš potplimne zone niske energije vode. Na temelju prisutnosti navedenih fosila uzorci s prevladavajućim udjelom bačinela, onkoida i bioklasta čine podtip MF1a dok uzorci u kojima većinom prevladavaju bentičke foraminifere, dekastroneme, fragmenti ljuštura školjkaša i dazikladalne alge čine podtip MF1b. Mikrofacijes MF2 obuhvaća sitnozrnastije mikritne vapnence (većinom madstone do pekstone) s intraklastima, bioklastima, peloidima, bentičkim foraminiferama te ljušturama školjkaša čime ukazuje na okoliš potplimne zone povišene energije vode. Na temelju navedenih elemenata razlikujemo podtipove MF2a, u kojem prevladavaju intraklasti, bioklasti kao i bentičke foraminifere dok peloidne čestice, bentičke foraminifere te u manjoj mjeri bioklasti prevladavaju u podtipu MF2b. Mikrofacijes MF3 obuhvaća zrnastije tipove vapnenaca (većinom vekstone–pekstone uz neke grejnstone) s litoklastima, bioklastima, peloidima, bentičkim foraminiferama (miliolidama), dekastronemama i dazikladalnim algama čime ukazuje na okoliš plimne zone. Na temelju prisutnosti navedenih fosila u uzorcima izdvojen je podtip MF3a u kojem dominiraju litoklastične i bioklastične komponente; u MF3b prevladava prisutnost bentičkih foraminifera i peloida. Mikrofacijes MF4 predstavlja prijelaz iz morskog okoliša (plimne zone) u slatkovodni okoliš pa razlikujemo fenestralne vapnence (MF4a) s fragmentima ljuštura ostrakoda, fenestralnim šupljinama, bioturbacijama i foraminiferama; te haroficejske vapnence (MF4b) s dominantnom pojavom slatkovodnih haroficeja i ostrakoda. Mikrofosilna zajednica s vrstama Palorbitolina lenticularis, Praechrysalidina infracretacea, Voloshinoides murgensis, Pseudolituonella conica, Archaealveolina reicheli ukazuje na stariju aptsku starost donjeg dijela slijeda. Na oko 10 m slijeda nalazi se trošniji horizont karakteriziran brečiranim i okršenim vapnencima s udubljenjima ispunjenim glinovitim matriksom. Mikrofosilna zajednica u uzorcima neposredno ispod te emerzijske površine je mlađeaptske (npr. Salpingoporella dinarica, Protochrysalidina elongata, Rumanoloculina minima), a iznad mlađealbske starosti (npr. Pseudonummoloculina heimi, Sigmoilina? sp., Novalesia cf. Angulosa, Vercorsella cf. immaturata Cuneolina parva, Nezzazatinella picardi), ukazujući da je to glavna aptsko–albska diskordancija. Emerzijske površine sličnih značajki nalaze se i na oko 14 m te 16,5 m slijeda mlađeg alba. Istraživani slijed naslaga ukazuje na relativno oplićavanje taložnih okoliša tijekom apta i uspostavljanje kopnenih uvjeta i nastanka paleotla na prijelazu apt–alb. Slijed alba u krovini paleotla karakteriziran je oscilirajućom transgresijom na koju ukazuju brojne emerzijske površine
Razvoj otvorenih edukacijskih materijala o trajnim magnetima i elementima rijetkih zemalja
No full textIn the frame of the EIT RawMaterials RECO2MAG project (https://reco2mag.rgf.bg.ac.rs/), which focus is on optimizing the manufacturing process of permanent magnet microstructures through novel grain boundary processing to produce resource-efficient sintered NdFeB PMs with lowered Dy content and improved energy products for use in novel electric motor designs, Open Educational Resources -OER (UNESCO, 2022) on permanent magnets and rare earth elements were developed. Firstly, syllabi for two online courses: (1) “Green Deal and Circular Economy Challenges of Rare Earthbased Permanent Magnets with Technical Aspects”, and (2) “Rare Earth Elements Value Chain Gaps and Opportunities in the ADRIA Region” were designed. The courses were aimed primarily at master’s and Ph.D. students, but also at researchers, policy-makers and raw material exploration and production experts worldwide, but with emphasis on RIS (Regional Innovation Scheme) countries, i.e. countries and regions in Europe where the pace of innovation is modest or moderate (https:// www.eitmanufacturing.eu/what-we-do/regional-innovation- scheme-ris/about-us/). Syllabi included: courses information (title, description, and instructor information); courses objectives, courses outlines (topics to be covered); course agenda; required materials; grading policy; and learning activities. Following the design of the syllabi, the online courses were successfully implemented in academic year 2022/23. Both courses had a shorter version consisting of six hours of lectures, panel discussions, and quizzes. Panel discussions and lectures were recorded. Successfully completed the long version of the course that included additional 24 hours of teamwork was awarded with one ECTS credit. For each course there were more than 100 applicants from more than 35 countries. Finally, short version of first and second workshop successfully passed 49 and 71 respectively. To ensure the courses’ sustainability, the learning materials and recorded lectures have been adapted as OER. These materials, including text, video, quizzes, and links to other open-source materials on the internet, are placed on the e-learning platform MoD (https:// mod.srce.hr/) using course design. MoD is an e-learning system based on the open-source Moodle software system established to support e-learning projects within the academic community. Copies of both e-courses have been placed in the Digital Academic Archives and Repositories (DABAR) of University of Zagreb Faculty of Mining, Geology and Petroleum Engineering (https://repozitorij. rgn.unizg.hr/) under the CC0 license. This type of Creative Commons licence implies that the contents are freely available to the public and can be accessed, reused, repurposed, adapted, and redistributed by anyone without any cost. The developed OER serve as a free and selfsustainable platform for the dissemination of knowledge gained during the project’s implementation
Larger benthic foraminifera as an important tool for palaeoenvironmental interpretation of Campanian inner platform settings, island of Brač (Croatia)
No full textThe informal group of larger benthic foraminifera (LBF) generally exhibits a high potential for biostratigraphy, palaeoenvironmental interpretations, and palaeobiogeographic comparisons in Tethys, especially during the Cretaceous greenhouse period. Late Cretaceous Global Community Maturation Cycle (GCMC) encompasses the Turonian‒Maastrichtian interval representing a special period of increasing diversity of LBF in shallow water settings. The LBF suffered from the palaeoenvironmental distributions associated with the Cenomanian‒Turonian boundary OAE2 event leading to the almost complete extinction. During the Coniacian‒Santonian, LBF already underwent a remarkable diversification in a wider area of Tethys associated with widely distributed extensive platform carbonate evolution. From Campanian inner platform facies, numerous taxa of LBF have been reported from Spain, Greece and Croatian island of Brač. Shallow-marine carbonate platform deposition on Brač represents an essential contribution to understanding Late Cretaceous evolution of one of the best preserved Mesozoic Perimediterranean carbonate platforms with especially favourable conditions for the development of LFB in Campanian (Gornji Humac and Pučišća fms) as a consequence of gradual progradation of platform environments over hemipelagic Dol fm resulted in diachronous upper boundary. Platform progradation resulted in establishment of shallow-marine environments progressively covering larger areas until the final covering of the Brač Marbles mb: Rasotica and Lovrečina mbrs of Pučišća fm that merged with the Gornji Humac fm. Such complexity of very different lithofacies enabled Campanian assemblages to be most diversified. Ongoing studies have revealed additional four new taxa (one new genus) of LBF described from lower–middle Campanian carbonates of the island of Brač, Croatia, two of them are also reported from time-equivalent strata of the Gavrovo–Tripolitza Platform (SW Greece), while providing further evidence for the pronounced Campanian diversification within the Late Cretaceous GCMC of AdCP
Use and comparison of unsupervised and supervised classification methods of SENTINEL-2 satellite images of Zagreb City area in R programming language : master's thesis
No full textKlasifikacija SENTINEL-2 satelitske snimke na području Grada Zagreba pomoću metoda nenadziranog i nadziranog strojnog učenja. Prikupljanje ulaznih podataka rađeno je u softveru QGIS. Izgradnja modela nenadzirane i nadzirane klasifikacije provedena je u R-studio-u. Usporedba točnosti predikcije korištenih modela random forest i extreme gradient boost. Vizualni pregled dobivenih rezultata stvorenih u programskom jeziku R.Classification of SENTINEL-2 satellite images of Zagreb City area using the methods of unsupervised and supervised machine learning. Input data collection was done in QGIS software. Construction of unsupervised and supervised classification models was performed in R-studio. Comparison of prediction accuracy of used random forest and extreme gradient boost models. Visual overview of the results created in R programming language
Drilling deeper in shallow geoexchange heat pump systems—thermogeological, energy and hydraulic benefits and restraints
No full textIn the last decade, due to climate change concerns and new environmental regulations in the EU, there was a tremendous rise in installed heat pump systems in new homes and buildings. The majority of these installed units are related to air-source heat pumps, as they offer a good trade-off between capital and operating expenses. However, when analysing heating and cooling heat pump systems from the primary energy consumption and ecological aspects, groundwater and shallow geothermal heat pump systems offer superior efficiency, compared to all market-available thermo-technical systems today. In the last decade, ground-source systems have seen some technological improvement by employing new borehole heat exchanger designs, such as piping with internal fins and a wider diameter (so called Turbocollector) to enhance the heat transfer between fluid and rock, as well as to reduce the pressure drop in the system. Furthermore, the process of drilling deeper offers higher ground temperatures and consequently higher seasonal performance factors in the heating cycle, due to the effect of the geothermal gradient. Nevertheless, although deeper boreholes provide better heat extraction rates per meter during the heat pump heating cycle, at the same time, it reduces heat rejection rates during the heat pump cooling cycle. The objective of this paper is to analyse and evaluate benefits and downsides of a new approach in the heat pump system design with deeper borehole heat exchangers of up to 300 m, comparing it to the traditional design of double-loop exchangers with 100 m depth. The geothermal borehole grid design simulation model, along with heat extraction and rejection, is performed on a yearly basis. The results are showing that the benefits of shallow geothermal boreholes, from the hydraulic and thermodynamic point of view, still dominate over deeper solutions
Investigating near-surface hydrologic connectivity in a grass-covered inter-row area of a hillslope vineyard using field monitoring and numerical simulations
No full textThe interplay of surface and shallow subsurface fluxes plays a critical role in controlling water movement in hillslope agroecosystems and impacting soil and plant health during prolonged dry periods, demonstrating a need for in-field monitoring. This study was conducted for two years (2021–2022) by combining field monitoring of the grass-covered inter-row area (passive wick lysimeter, surface runoff, and meteorological data), laboratory determination of soil hydraulic properties (SHPs), and numerical modeling with the aim to explore near-surface fluxes at the SUPREHILL Critical Zone Observatory (CZO) located on a hillslope vineyard. Additionally, sensitivity analysis for basic root water uptake (RWU) parameters was conducted. The model was evaluated (R2, RMSE, and NSE) with lysimeter (hillslope) and runoff (footslope) data, producing good agreement, but only after the inverse optimization of laboratory estimated hydraulic conductivity was conducted, demonstrating that adequate parameterization is required to capture the hydropedological response of erosion-affected soil systems. Results exhibit the dependence of runoff generation on hydraulic conductivity, rainfall, and soil moisture conditions. The data suggest different soil-rewetting scenarios based on temporal rainfall variability. Sensitivity analysis demonstrated that Leaf Area Index (LAI) was the most responsive parameter determining the RWU. The study offers an approach for the investigation of fluxes in the topsoil for similar sites and/or crops (and covers), presenting the methodology of self-constructed soil–water collection instruments
Environmental protection in natural gas industry : comparison of different spatio-temporal radiological risk assessment scenarios
No full textThe paper analyses results of spatio-temporal radiological risk assessment
scenarios based on existing in-situ long-term monitoring data from a natural
gas processing plant to analyse the effect of different input data on the
assessment outcome. The ERICA Assessment Tool was used to estimate the dose
rates to biota and potential impacts due to the exposure to ionising
radiation. The input data for radiological risk assessment scenarios
included annual data on activity concentration of radionuclides in soil
from measurements performed from 1994 to 2016 and laboratory
gamma-spectrometric data related to the period from 2014 to 2019. Predicted
total dose rate to biota was generally below the ERICA Tool's screening dose
rate of 10 μGyh-1 or slightly above, with the highest total dose rate
estimated for lichen and bryophytes. Total dose rates to lichen and
bryophytes in the studied period show certain temporal variation, but a
specific trend was not detected. Estimated total dose rates to biota from
different assessment scenarios were below internationally proposed reference
levels for which no detrimental effects are expected. The overall potential
radiological risk to terrestrial biota from the operation of the natural gas
processing plant was found to be negligible
Analiza digitalnog modela terena na području Parka prirode Papuk : završni rad
No full textU ovom završnom radu odradili smo analizu digitalnog modela terena na području Parka prirode Papuk. U uvodu su navedene osnovne informacije o Parku prirode Papuk, njegov geografski položaj, povijest Parka prirode, te vrsta stijena. Opisana je georaznolikost i geološka građa Parka prirode Papuk. Analiza digitalnog modela temelji se na metodama GIS-a, te ostatak postupka opisan je u radu