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1.
Characterization of a karst aquifer in the recharge area of Malenščica and Unica springs based on spatial and temporal variations of natural tracers
Blaž Kogovšek, 2022, doctoral dissertation

Abstract: The aim of the present study is to characterize and improve the still insufficient knowledge of the recharge processes that have an important influence on the flow and solute transport in karst aquifers and thus also on the quantity and quality of karst water sources. A binary karst aquifer in the recharge area of the Malenščica and Unica springs, which covers an area of about 820 km2 in SW Slovenia, was selected as the study area. A dense monitoring network was established at 20 observation points (six springs, four ponors, seven water-active caves and three surface streams) for simultaneous monitoring of the hydrological characteristics and the physicochemical properties of the water, the so-called natural tracers. Data-loggers were installed to measure water pressure, temperature and conductivity. During selected storm events, samples were taken for chemical and microbiological analyses and discharge measurements were made. The meteorological and hydrological data of the Slovenian Environment Agency complemented the extensive dataset. Collected data allowed the analysis and comparison of the spatial and temporal variations of the natural tracers under different hydrological conditions. Frequent discharge measurements allowed the generation of rating curves and proved to be a crucial element for understanding the hydraulic processes that determine the functioning of this system. The calculation of the water budget allowed an assessment of the proportion of autogenic and allogenic recharge of the springs and a quantitative estimate of autogenic recharge under different hydrological conditions. The hydrological analysis, i.e. the flow duration curve, the hydrograph separation techniques and the recession analysis, revealed that the Malenščica spring has a higher storage capacity, a greater proportion of autogenic recharge, especially at low-flow, and a slower recession than the Unica spring. This was also confirmed by correlation and spectral analyses, which were also used to investigate the relationships between discharges at ponors and springs. However, the results of the cross-correlation analysis showed hardly any difference between the two springs and in this case proved to be unsuitable for studying the influence of allogenic recharge. Instead, partial cross-correlation analysis was used to control the input parameters of effective precipitation and discharge of one of the sinking streams to determine the contribution of the other sinking stream to the observed spring. The results confirmed differences in allogenic recharge of the Unica and Malenščica springs. Hysteresis analysis has been applied as a complementary method to time series analysis and represents an improved approach to the characterization of the karst hydrological system. The hydraulic approach to the construction of hysteresis enabled a detailed analysis of allogenic and autogenic water interaction and its influence on the Malenščica and Unica springs under different hydrological conditions. Narrow shapes of the hysteresis indicate a direct hydraulic connection between the ponor and the spring and thus a well-developed drainage system. Any deviation towards a convex or concave shape indicates a less developed, more matrix-related drainage system or the influence of other recharge sources. Analysis of physicochemical hysteretic function of individual locations confirmed the differences in the recharge characteristics of the two springs. Compared to the Unica spring, the Malenščica spring has specific recharge characteristics that result in lower vulnerability to the effects of the sinking streams. A greater proportion of autogenic recharge in the initial phase of the storm event is important, as it allows for a time delay of the possible negative effects of the sinking stream. However, possible pollution from the area of autogenic recharge can have strong negative effects, as in this initial phase with low discharges the dilution effect is negligible.
Keywords: karst aquifer, dynamics of natural tracers, storm events, discharge measurements, time series analysis, hysteresis, Unica spring, Malenščica spring
Published in RUNG: 01.03.2022; Views: 2078; Downloads: 94
.pdf Full text (18,38 MB)

2.
UPORABA NARAVNIH SLEDIL ZA DOLOČANJE ZNAČILNOSTI KRAŠKIH IZVIROV NA OBROBJU PLANINSKEGA POLJA (JZ Slovenija)
Teja Melinc, 2019, master's thesis

Abstract: Izvir Malenščica je pomemben vir oskrbe s pitno vodo za približno 21.000 prebivalcev v občinah Postojna in Pivka. Poleg izvira Unice je eden od dveh večjih kraških izvirov na južnem robu Planinskega kraškega polja v jugozahodni Sloveniji. Oba izvira se polnita iz kompleksnega kraškega sistema, za katerega je značilna izmenjava med površinskim in podzemnim tokom. Pri določanju značilnosti kraških izvirov smo uporabili metodo sledenja z naravnimi sledili, ki vključuje merjenje naravnih lastnosti vode, kot so pretok, temperatura, električna prevodnost in kemijska sestava vode v različnih točkah znotraj kraškega vodonosnega sistema in pri tem merimo spreminjanje teh parametrov s časom ob različnih hidroloških pogojih. Za preučevanje in obdelavo teme magistrske naloge smo imeli štiri skupine podatkov, ki smo jih predhodno zbrali in ustrezno obdelali. Prva skupina je zajemala podatke merjenja specifične električne prevodnosti v 30-minutnih intervalih v obeh izvirih ter ponikalnicah Pivka in Rak v njunem prispevnem zaledju za obdobje od 15. 10. 2016 do 4. 1. 2017, ko so hidrološke razmere variirale od nizke do visoke vodne gladine in nato spet v bolj suho obdobje konec leta 2016. Druga skupina je zajemala podatke občasnih osnovnih kemijskih analiz ter analiz kovin za izvir Malenščica za daljše obdobje, in sicer od 17. 4. 2007 do 10. 10. 2017. Tretja skupina podatkov predstavlja rezultate analize kemijskih in mikrobioloških podatkov v obeh izvirih in obeh ponikalnicah med vodnim valom za obdobje od 7. 9. 2017 do 3. 10. 2017. Četrti sklop podatkov pa spet zajema za vse štiri lokacije rezultate, pridobljene v sklopu izdelave magistrske naloge, z izvedbo podrobnega vzorčenja in kemijsko analizo vzorcev v času vodnega vala za obdobje od 10. 5. 2019 do 15. 5. 2019. Primerjava različnih skupin podatkov za štiri vzorčevalna mesta (Malenščica, Unica, Rak in Pivka) je omogočila boljše razumevanje odnosov med različnimi deli zaledja in spreminjanja njihovih deležev pri napajanju obeh izvirov ob različnih hidroloških razmerah. Na osnovi določitve časovnih zamikov med vrhovi in doli krivulj specifične električne prevodnosti smo tudi ocenili navidezne hitrosti toka podzemne vode med ponikalnicami in izviri. Na podlagi primerjave sprememb fizikalnih, kemijskih in mikrobioloških parametrov za različne padavinske in hidrološke razmere izvirov in vodnih tokov v njunem zaledju smo lahko sklepali o značilnostih pretakanja podzemne vode v obravnavanem kraškem vodonosniku.
Keywords: Naravna sledila, kras, Planinsko polje, vodni vir, fizikalni in kemijski parametri, mikrobiološki parametri.
Published in RUNG: 25.11.2019; Views: 4003; Downloads: 119
.pdf Full text (2,95 MB)

3.
Količinsko in kakovostno ovrednotenje vodnih virov v razpoklinskem in kraškem vodonosniku na območju občine Postojna
Špela Maček, 2018, master's thesis

Abstract: Glavni vir pitne vode na območju občin Postojna in Pivka je kraški vodni vir Malenščica. Izdatnost vodnega vira je dovolj velika, da zagotavlja zadostno količino vode tudi ob nizkem vodostaju, zaradi velikega prispevnega zaledja pa je kakovost vode stalno ogrožena. Magistrska naloga opisuje izvire na območju razpoklinskega vodonosnika Planinske gore in kraški izvir Korentan, ki predstavljajo možne rezervne vodne vire. V nalogi smo te vodne vire podrobneje opisali, proučili smo geološke in hidrogeološke značilnosti obravnavanega območja in izdelali litološko ter hidrogeološko karto, opredelili dejanske in potencialne vire onesnaženja. Obstoječe podatke o fizikalno kemijskih in mikrobioloških lastnostih izvirov smo dopolnili z občasnim vzorčenjem in analizami teh parametrov v obdobju od aprila 2016 do januarja 2018. Na osnovi primerjave rezultatov analiz smo sklepali na značilnosti vodonosnikov v zaledju izvirov, primerjava s Pravilnikom o pitni vodi pa je omogočila tudi oceno njihove kakovosti. Ocenili smo razpoložljive količine podzemne vode z izračunom količine infiltriranih padavin na območju vodonosnikov in oceno specifičnega odtoka z območja napajanja vodonosnika. Izsledke smo povezali v oceno primernosti obeh območij kot rezervnega vodnega vira glede na kakovostno in količinsko stanje. Povzamemo lahko, da vodni vir Korentan v času srednjega odtoka količinsko zadostuje za uporabo, v času nizkega odtoka pa je njegova kapaciteta premajhna. Vodonosnik Planinske gore pa ima dovolj vode tudi ob minimalnem vodostaju in bi ob ustrezni tehnični rešitvi lahko pokril potrebe po pitni vodi na tem območju. Surova voda obeh vodnih virov je glede na mikrobiološke raziskave neprimerna za distribucijo, saj je bakteriološko oporečna. S primerno tehnologijo čiščenja pa bi bila primerna za uporabo.
Keywords: kraški in razpoklinski vodonosnik, kakovost, količina, vodni vir, Planinska gora, Korentan
Published in RUNG: 12.09.2018; Views: 3948; Downloads: 174
.pdf Full text (6,86 MB)

4.
Influence of Fe-Content on Visible Light Photoactivity of Bi-Pyrochlores
Matjaž Valant, Benčina Metka, 2017, published scientific conference contribution abstract (invited lecture)

Keywords: piroklori, fotokatalizatorji, rekombinacija
Published in RUNG: 20.07.2017; Views: 4485; Downloads: 0
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5.
PLATOON Kunsthalle Berlin, kot začasni eksperimentalni prostor in socialna skulptura : Eat Meat
Marija Laura Potočnik, 2016, undergraduate thesis

Abstract: Teoretični del diplomske naloge zajema in obravnava začasni eksperimentalni prostor PLATOON Kunsthalle Berlin kot socialno skulpturo. Uvodno temo odprem z razlago, zakaj sem izbrala PLATOON Kunsthalle Berlin za vsebino te diplomske naloge ter jo na kratko predstavim. Sledi definicija pojma socialne skulpture ter predstavitev Josepha Beuysa, umetnika, ki je izraz prvi uporabil. Za tem povežem in kategoriziram PLATOON Kunsthalle kot socialno skulpturo, jo podrobno predstavim od ustanovitve do postavitve v Berlinu, obdelam njeno skupnost in opišem njen vpliv na berlinsko umetniško sceno ter orišem organizacijo PLATOON Cultural Development. Praktični del tega diplomskega dela je video inštalacija EAT MEAT?, v kateri si postavljam vprašanja o morali, družbi ter o odnosu do živali. Na podlagi Freudove delitve osebnosti raziskujem človeško - živalske odnose in človekovo moralno vlogo v teh odnosih ter vlečem vzporednice med vrednotami. Inštalacija je avtobiografsko delo, intimno in subjektivno. Njen namen je vzbuditi zavedanje in razmislek o tem, v kakšni družbi pravzaprav živimo, kakšne posledice puščajo naša dejanja in udobje, ker oboje nam vsiljuje ignoranca industrije v svojem brezkompromisnem boju za zaslužek.
Keywords: PLATOON, Kunsthalle, Berlin, socialna skulptura, eksperimentalni prostor, umetniška scena, video inštalacija, družba, morala, meso, srce
Published in RUNG: 01.02.2017; Views: 5354; Downloads: 199
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6.
Hydrogeological and speleological research of the spring cave Slatinski Izvor and its recharge are (Republic of Macedonia)
Biljana Gichevski, 2016, doctoral dissertation

Abstract: This thesis represents a comprehensive study, giving first extensive information on the hydrogeological and speleological characteristics of the spring cave Slatinski Izvor and its catchment area. The researched spring is located in the Poreče basin of West-Central Macedonia, in the river valley of Slatinska Reka. The wider area around the spring belongs to two tectonic units. The Slatinski Izvor spring is situated on the Pelagonian horst anticlinorium, which is composed of carbonate rocks. The second is the Western Macedonian zone, and it is composed of non-carbonate rocks. The spring represents a significant potential for water supply for the settlement Slatina. Prior to this research only some basic information about the karst aquifer in Precambrian dolomite marbles was available. Therefore, my goal was to ensure better understanding of the functioning of the karst system in the recharge area of the spring, assessment of its vulnerability to various pollution sources, as well as study of karst development of the area. Because karst aquifers have unique hydrogeological characteristics and specific nature, they also require specifically adapted investigation methods. In order to reach the main goal, speleological investigations, hydrological methods, hydrochemical methods and tracer test were used. A monitoring network was combined with regular samplings for major and trace elements analysis, which enabled considerable advances in understanding the functioning of the karst system. The data from two-year period (December 2011 – November 2013) was compared and analyzed. The controlling of the karst development in the study area mostly depends on the tectonic and geologic conditions. Incision of Slatinska Reka is the main controlling factor in cave development by lowering the base level of karst terrains. All investigated caves (Gorna Slatinska, Slatinska II, Ovčarska Peštera, Puralo, Slatinski Izvor) have “normal” epigenic karst development. Slatinski Izvor is the youngest cave. The Slatinski Izvor spring serves as a cave entrance for the same cave and, represents the outflow of groundwater from the karst system. A conceptual model of the karst system of the study area was developed. The Slatinski Izvor spring has typical karst hydrological regime. The karst system is well developed by conduits and rains infiltrated into vadose zone flow rapidly towards the spring. The travel time of low mineralized water within the system corresponds well with the results from an artificial tracer test. Performed artificial tracer test confirmed that the Slatinski Izvor spring is recharged by allogenic stream. The dominant apparent flow velocity of 250 m/h, a single peak of the tracer breakthrough curve and more than 87% of tracer recovered indicate a rapid conduit flow and high vulnerability of the observed drinking water source. Analysis of spatial and temporal variations of physical and chemical parameters show that waters in the study area had different origin and were transmitted along different flow paths. The origin of the water of the Slatinski Izvor spring is from non-carbonate area, but the influence of mixed limestone-dolomite sequence in the carbonate area is significant. The results point out to short residence time of the water in the karst aquifer. The anthropogenic impact in the study area is insignificant which is reflected in the good water quality. In order to preserve it, land surface zoning was performed in terms of groundwater and spring water vulnerability to pollution according to the hydrogeological research. A comprehensive research with a combined use of various research tools presents an innovative approach and a new contribution to the Macedonian karstological science. Applied methods proved to be successful for to study of the karst system. Finally, the results of the study have clear applicative significance in terms of drinking water management.
Keywords: karst hydrology, cave, speleological investigation, hydrochemistry, tracer test, spring Slatinski Izvor
Published in RUNG: 14.10.2016; Views: 30140; Downloads: 158
.pdf Full text (11,01 MB)

7.
Vpliv hidroloških razmer na kakovost kraških vodnih virov - primer izvira Rižane
Lucija Vodir, 2016, undergraduate thesis

Abstract: Brez vode na Zemlji ne bi bilo življenja. Pomembni viri pitne vode so kraški vodonosniki, ki so zelo dovzetni za onesnaževanje, predvsem zaradi njihove velike prepustnosti in s tem hitre infiltracije vode v podzemlje. Tudi reka Rižana se napaja iz kraškega vodonosnika v zaledju in je glavni vir pitne vode za prebivalce Slovenskega primorja. Predstavljene meritve in vzorčenja so potekala v okviru projekta »ŽIVO! Življenje – voda« v sklopu čezmejnega programa Slovenija – Hrvaška 2007–2013. Za oceno stanja vodotoka Rižane sem pridobljene podatke s terena primerjala z meritvami, ki jih opravlja Agencija RS za okolje na izviru Zvorček in na merilnem mestu Rižana – Dekani za obdobje 2007–2013. Poleg tega sem za obdobje 2010–2013 dodala še podatke Nacionalnega laboratorija za zdravje, okolje in hrano, ki so bili pridobljeni na izviru Zvorček. Pri vseh merjenih parametrih se je pokazalo, da se ob spremembi hidroloških razmer, torej ob padavinskih dogodkih, vsebnost parametrov poveča, saj voda, ki se infiltrira v tla, s seboj prinese tudi onesnaženje. Najhujši onesnaževalci so kmetijstvo, industrija, odlagališča odpadkov in promet. Kljub temu pa mejne vrednosti niso bile presežene, razen v primeru mikrobioloških parametrov. Primerjava z obdobjem 2007–2013 je pokazala podobne rezultate. Prenos onesnaženja je torej vezan na padavinske dogodke in to odvisnost kakovosti vode od hidroloških razmer je treba upoštevati pri načrtovanju monitoringa kakovosti kraških vodnih virov.
Keywords: kras, voda, Rižana, hidrološke razmere, kakovost vode
Published in RUNG: 20.01.2016; Views: 6694; Downloads: 306
.pdf Full text (3,60 MB)

8.
9.
Water pollution in the impact areas of the two abandoned metal ore mines in Slovenia and Portugal
Doroteja Gošar, 2015, undergraduate thesis

Abstract: Mining in both Mežica zinc and lead mine and in Freixeda gold mine caused negative environmental impacts. The main objective of the thesis was to study negative impacts on water quality through time. During the process various literature sources were studied, field work and chemical analyses were performed and interpretation of results with different statistical methods was done. In Mežica mine the quality of surface water has improved through time and nowadays the Meža River is of good quality. The biggest change was shown in the case of Helena rivulet, where Pb, Zn and Cd concentration between 2002 and 2015 lowered below limit values. Preventive measures and treatment of waste deposits had positive impact on water quality and based on standards for drinking water, groundwater from mine could be a source of drinking water. In Freixeda stream concentration of heavy metals lowered through time and in 2015 values of Zn, Pb, Cd and Cu in Freixeda stream before confluence with the Tua River were below the limit value. An exception is the increased value of As, which was caused by acid mine drainage (AMD) inflow from the mine, but also by the discharge from confined aquifer to Freixeda stream. Treatment of AMD was efficient for a while but due to lack of maintenance it is no longer effective.
Keywords: Abandoned mines, heavy metals, pollution, Mežica mine, Freixeda mine
Published in RUNG: 05.10.2015; Views: 5912; Downloads: 320
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10.
Bi2O3-BASED PYROCHLORE NANOSTRUCTURES AND THEIR CRYSTALLOGRAPHIC, OPTOELECTRONIC AND PHOTOCATALYTIC PROPERTIES
Metka Benčina, 2015, doctoral dissertation

Abstract: Bi2O3-based pyrochlore nanomaterials and their photocatalytic, optoelectronic and crystallographic properties are the research topics of this doctoral dissertation. We synthesized these materials at nanoscale, since they are expected to possess photoactivity in the visible-light spectrum, which is an important target for the high-performance photocatalysts. To prepare nanoparticles that are not agglomerated, different synthesis methods (coprecipitation, coprecipitation followed by the digestion, reverse micelle) and post-treatments (furnace or hydrothermal reactor) were examined. Micrometer size materials were prepared with the solid-state reaction and annealing at high temperature. Bi2Ti2O7 nanoparticles were synthesized with the coprecipitation reaction, followed by annealing at 570 °C in the furnace or in the hydrothermal reactor at 230 °C for 18h in NH4OH medium. UV-Vis diffuse reflectance spectra of the Bi2Ti2O7 samples showed that they exhibit the maximum absorption edge at ~420-440 nm. The UV-Vis diffuse reflectance measurements of Bi2Ti2O7 loaded with 10 wt. % of Ag as a co-catalyst showed an enhanced absorbance in the visible region, presumably due to a contribution of Local Surface Plasmon Resonance. The Bi2Ti2O7 nanoparticles are not photocatalytically active under the visible light irradiation without assistance of a sacrificial reagent. The photocatalytic activity does not increase even with Ag as a co-catalyst under visible light irradiation. All samples are active under UV light irradiation, especially the sample with Ag that is able to decolourize 7 mg/L of metyl orange in just 3 min of exposure to UV light. However, H2O2 as a sacrificial reagent increases the photocatalytic activity of Bi2Ti2O7 under visible light irradiation. Phase pure pyrochlore Bi1.647Nb1.118Fe1.157O7 (BNF) nanoparticles were synthesized with coprecipitation reaction and further annealing in the furnace at 570 °C for 7h or 15h and in the hydrothermal reactor at 160 °C for 18h in 3 M or 6 M NaOH medium. The BNF materials exhibit shift toward longer wavelengths in absorbance of visible light (up to ~550-650 nm). This result confirmed that incorporation of Fe in the pyrochlore structure decreases the band gap. The BNF nanoparticles annealed for 7h showed intense photoactivity under visible light irradiation in the presence of a sacrificial reagent. The improved photoactivity, much better than with BNF, was shown for the composite nanoparticles BiOCl/BNF. They decolourize 100 % of the 7 mg/L methyl orange within only 2h of the visible light irradiation in the presence of H2O2. Phase pure pyrochlore Bi1.9Te0.58Fe1.52O6.87 (BTF) nanoparticles were synthesised by coprecipitation reaction and further annealing in the furnace at 570 °C for 7h. Although the BTF nanoparticles include higher amount of Fe than BNF nanoparticles and exhibit narrower band gap, the photoactivity of these nanoparticles is a bit lower than that of BNF nanoparticles. We assume that Fe at some critical concentration causes formation of mid-band states, which act as recombination centers. The same as BiOCl/BNF, the BiOCl/BTF composite is able to decolourize 100 % of the 7 mg/L MO within 2h of the visible light irradiation in the presence of H2O2. Based on the band gap determination and estimation of valence and conduction band levels, the proposed photodecolourization mechanisms are discussed. The conduction band levels of all synthesized materials lie more positively than O2/O2● redox potential (vs. negative hydrogen electrode potential), but are more close to H2O2/●OH redox potential. Thus, we assume that the photogenerated electrons form ●OH radicals, the species that induce dye decolourization under visible light irradiation. We believe that better performance of composite materials (BiOCl/BNF, BiOCl/BTF) is due to the formation of heterojunction, which facilitates the electron transfer between semiconductors, and O2 vacancy states formation in the BiOCl material.
Keywords: nanoparticles, pyrochlore structure, photocatalysis, visible light
Published in RUNG: 26.06.2015; Views: 8751; Downloads: 210
.pdf Full text (7,29 MB)

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