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Povzetek: The use of geothermal energy, which comes from both deep geothermal systems and the shallow underground, has been developing rapidly in the last few decades. The purpose of the paper is to present the results of measurements of the thermal properties of all rock samples and sediments that were available from boreholes, two tunnels and numerous surface locations in Slovenia in the period from 1982 to the end of 2022. In relation to the shallow geothermal potential, a special effort is needed to characterize the thermal properties of the rocks and sediments and to implement thermal energy transfer technology. In this sense, knowledge of the thermal conductivity of rocks and sediments is required to assess the possibility of low-enthalpy heat exchange in a given local area. The largest number of measurements was taken to determine thermal conductivity. Determinations of thermal diffusivity were carried out on a much smaller number of rock and sediment samples, as well as determinations of radiogenic heat production in rocks. The results of thermal conductivity measurements on 430 samples from 119 wells, 20 samples from two tunnels and 156 samples from surface locations are shown. The highest thermal conductivities are shown by samples of dolomite, quartz conglomerate and conglomerate, phyllonite, quartz phyllite and gneiss, while the lowest are measured in sediments such as clay, lignite with clay, peat and dry sand. The determined radioactive heat generation is the lowest for milonitized dolomite and highest for dark grey sandstone with shale clasts. Our results are comparable to those already published worldwide, and they could be the basis for the possible future Slovenian standard for the thermal properties of measured rocks and sediments.
Ključne besede: thermal conductivity, thermal diffusivity, borehole, tunnel, surface, rock, sediment, radioactive heat generation, Slovenia
Objavljeno v DiRROS: 15.01.2024; Ogledov: 165; Prenosov: 84
Celotno besedilo (6,03 MB)
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Povzetek: The origin of the soils formed on carbonate rocks remains uncertain, as they are probably of polygenetic origin. Of particular interest are the elevated contents of some trace elements detected in these soils, as they can hardly be attributed to insoluble residues of carbonate rock. The aim of this study was to uncover the relationship between heavy minerals in bedrock and soil and to identify other sources that influence the mineral and chemical composition of soil. We investigated representative samples of soils and dolomite bedrock as well as sandstones and marlstones from the nearby flysch basin as an expected source of the aeolian contribution. XRD and SEM/EDS showed that mineral diversity is higher in soils compared to the dolomites. Heavy minerals found in dolomite insoluble residue include sphalerite, Ti-oxide (probably rutile), zircon, fluorite, pyrite, minerals of REE phosphates and apatite group, interpreted as terrigenous detrital material. The mineral composition of soil heavy fraction is only partly following insoluble residues of bedrock and indicates possible aeolian contribution. Comparison with nearby flysch sandstones and marlstones showed similarities in mineralogical diversity by the presence of chromite and Fe-Cr(Mn) oxides (probably carmichaelite). Other minerals present in soils and flysch layers, such as Ti-oxide (probably rutile), zircon, REE phosphates, and pyrite grains, however, show similarities in mode of occurrence and transport indications. Signs of aeolian transport on the grains detected in soils were further confirmed by SEM/EDS.
Ključne besede: Phaeozem, Upper Triassic dolomite, flysch layers, trace elements, SEM/EDS
Objavljeno v DiRROS: 04.01.2024; Ogledov: 214; Prenosov: 51
Celotno besedilo (8,60 MB)

Objavljeno v DiRROS: 06.12.2023; Ogledov: 202; Prenosov: 56
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Povzetek: Izhodišča. Rak dojk (RD) je zaradi visoke incidence v razvitem svetu in v Sloveniji velik zdravstveni in ekonomski problem. Redno mamografsko pregledovanje asimptomatskih žensk (presejanje oz. screening), starih 50-69 let dolgoročno zmanjša umrljivost za RD, ker odkrije raka v zgodnejši fazi. V Sloveniji presejanje ni organizirano tako kot v nekaterih evropskih državah, ampak je oportunistično, ko ženske preventivno prihajajo v centre za bolezni dojk (CBD) na pregled po priporočilu zdravnika ali po lastni želji. Za kakovost delovanja centri nimajo enotnih državnih smernic in nad njihovim delovanjem ni nadzora. Zaključki. Uspešnost presejanja je odvisna od izbora skupine primerne starosti, udeležbe, intervala med posameznimi krogi presejanja, števila projekcij, dvojnega odčitovanja, kontrole kakovosti ter rednega beleženja in analize doseženih rezultatov. Glavne pomanjkljivosti presejanja so napačno pozitivni in napačno negativni izvidi, izpostavljenost ionizirajočem sevanju ter prediagnosticiranost.
Objavljeno v DiRROS: 01.12.2023; Ogledov: 163; Prenosov: 57
Celotno besedilo (639,35 KB)

Povzetek: To achieve sustainable and efficient use of shallow geothermal resources, it is important to understand the heat transfer in the subsurface of the planned geothermal system. In the City Municipality of Murska Sobota, NE Slovenia, the use of geothermal open-loop systems has increased in recent years. Their high spatial density raises the question of possible mutual interference between the systems. By compiling geological, hydrogeological, and thermal data, obtained from the monitoring network, fieldwork, and knowledge of regional hydrogeological conditions, we have developed a transient groundwater flow and heat transfer model to evaluate the impact of the open-loop systems on the subsurface and surrounding systems. The transient simulation showed that the thermal state in the observed area is restored over the summer, when the systems are not in operation. Also, the systems do not have significant mutual interference that would affect their efficiency. However, as interest in installing new systems in the area increases, simulations of the thermal plumes of new geothermal systems are needed to ensure sustainable and efficient use of shallow geothermal energy in the future.
Ključne besede: geothermal energy, open-loop system, groundwater heat pump, intergranular aquifer, numerical modelling, thermal plume
Objavljeno v DiRROS: 19.09.2023; Ogledov: 361; Prenosov: 96
Celotno besedilo (36,17 MB)