Repozitorij Univerze v Novi Gorici

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Regional biodiversity and seasonal dynamics of the bacterial communities in karstic springs of Slovenia
Maja Opalički Slabe, 2019, doktorska disertacija

Opis: Information on groundwater’s natural bacterial communities is important for evaluating pristine groundwater’s quality, as environmental changes potentially lead to alterations in bacterial community structures. In four seasons, 15 hypothetically pristine springs across five karst eco-regions in Slovenia (Central Europe) were analysed during their low discharge, and their basic physical and chemical parameters were recorded. The diversity of bacterial community structures was assessed with a terminal restriction fragment length polymorphism fingerprinting method. Total cell counts as bacterial abundance and electron transport system activity as bacterial respiratory activity were used for quantitative evaluation of bacterial communities. To detect anthropogenic pollution, spring water was tested by the cultivation of coliform bacteria and Escherichia coli (E. coli). Results indicate distinct regional differences in environmental parameters, bacterial respiratory activity, presence of coliforms and E. coli, bacterial abundances, and qualitative bacterial community structures, but there were no regional differences in the numbers of operational taxonomic units and biodiversity indices (Shannon-Wiener’s and Simpson’s diversity index, Buzas and Gibson’s evenness). The analysis of seasonal environmental parameters showed significant differences in dissolved organic carbon and pH, and also significant changes in bacterial respiratory activity and abundances, as well as differences in bacterial community structures, the numbers of operational taxonomic units, and biodiversity indices. No seasonal variations were shown for coliforms and E. coli. Despite seasonal oscillations, regional differences prevailed among five karst eco-regions and indicate a significant influence on the qualitative and quantitative aspects of groundwater bacterial community structures. The study confirmed both regional and seasonal differences in groundwater bacterial community structures, which should be included in further sustainable management plans of the aquifers.
Najdeno v: ključnih besedah
Povzetek najdenega: ...cell counts as bacterial abundance and electron transport system activity as bacterial respiratory activity were...
Ključne besede: karst springs, bacterial community structure (BCS), terminal restriction fragment length polymorphism (T-RFLP), total cell counts (TCC), electron transport system activity (ETSA)
Objavljeno: 26.06.2019; Ogledov: 987; Prenosov: 49
.pdf Polno besedilo (3,76 MB)

Atmospheric chemistry and physics in the atmosphere of a developed megacity (London): An overview of the REPARTEE experiment and its conclusions
Gavin J Phillips, Carole Helfter, Chiara F Di Marco, Eiko Nemitz, Fay Davies, Janet F Barlow, Tyrone Dunbar, Iain R White, Dudley E Shallcross, Stephen J Henshaw, K Fredrik Peterson, Brian Davison, Damien Martin, Ben Langford, C Nicholas Hewitt, Stephen M Ball, Justin M Langridge, A K Benton, Roderick L Jones, Paul I Williams, John Whitehead, Martin W Gallagher, Claire Martin, James R Dorsey, Hugh Coe, James D Allan, William J Bloss, Alistair J Thorpe, David C S Beddows, Manuel DallOsto, Roy M Harrison, Steven Smith, 2012, pregledni znanstveni članek

Opis: The Regents Park and Tower Environmental Experiment (REPARTEE) comprised two campaigns in London in October 2006 and October/November 2007. The experiment design involved measurements at a heavily trafficked roadside site, two urban background sites and an elevated site at 160-190 m above ground on the BT Tower, supplemented in the second campaign by Doppler lidar measurements of atmospheric vertical structure. A wide range of measurements of airborne particle physical metrics and chemical composition were made as well as measurements of a considerable range of gas phase species and the fluxes of both particulate and gas phase substances. Significant findings include (a) demonstration of the evaporation of traffic-generated nanoparticles during both horizontal and vertical atmospheric transport; (b) generation of a large base of information on the fluxes of nanoparticles, accumulation mode particles and specific chemical components of the aerosol and a range of gas phase species, as well as the elucidation of key processes and comparison with emissions inventories; (c) quantification of vertical gradients in selected aerosol and trace gas species which has demonstrated the important role of regional transport in influencing concentrations of sulphate, nitrate and secondary organic compounds within the atmosphere of London; (d) generation of new data on the atmospheric structure and turbulence above London, including the estimation of mixed layer depths; (e) provision of new data on trace gas dispersion in the urban atmosphere through the release of purposeful tracers; (f) the determination of spatial differences in aerosol particle size distributions and their interpretation in terms of sources and physico-chemical transformations; (g) studies of the nocturnal oxidation of nitrogen oxides and of the diurnal behaviour of nitrate aerosol in the urban atmosphere, and (h) new information on the chemical composition and source apportionment of particulate matter size fractions in the atmosphere of London derived both from bulk chemical analysis and aerosol mass spectrometry with two instrument types.
Najdeno v: ključnih besedah
Povzetek najdenega: ...nanoparticles during both horizontal and vertical atmospheric transport; (b) generation of a large base of...
Ključne besede: megacity, trace gas, urban atmosphere, atmospheric transport, chemical composition, aerosol
Objavljeno: 18.07.2019; Ogledov: 769; Prenosov: 0
.pdf Polno besedilo (4,66 MB)

Enhancement of Charge Transport in Polythiophene Semiconducting Polymer by Blending with Graphene Nanoparticles
Egon Pavlica, Gvido Bratina, 2019, izvirni znanstveni članek

Opis: This paper describes a study on the charge transport in a composite of liquid‐exfoliated graphene nanoparticles (GNPs) and a polythiophene semiconducting polymer. While the former component is highly conducting, although it consists of isolated nanostructures, the latter offers an efficient charge transport path between the individual GNPs within the film, overall yielding enhanced charge transport properties of the resulting bi‐component system. The electrical characteristics of the composite layers were investigated by means of measurements of time‐of‐flight photoconductivity and transconductance in field‐effect transistors. In order to analyze both phenomena separately, charge density and charge mobility contributions to the conductivity were singled out. With the increasing GNP concentration, the charge mobility was found to increase, thereby reducing the time spent by the carriers on the polymer chains. In addition, for GNP loading above 0.2 % (wt.), an increase of free charge density was observed that highlights an additional key role played by doping. Variable‐range hopping model of a mixed two‐ and three‐dimensional transport is explained using temperature dependence of mobility and free charge density. The temperature variation of free charge density was related to the electron transfer from polythiophene to GNP, with an energy barrier of 24 meV.
Najdeno v: ključnih besedah
Ključne besede: grafen, polimeri, transport električnega naboja, časovno odvisna fotoprevodnost
Objavljeno: 23.08.2019; Ogledov: 616; Prenosov: 0
.pdf Polno besedilo (1,78 MB)

Reshaping metropolitan transportation cultures. A comparative study of bicycle friendly cities in Europe and the case of the Metropolitan City of Milano
Ario De Marco, 2019, doktorska disertacija

Najdeno v: ključnih besedah
Povzetek najdenega: ...urban mobility, bicycle, urban landscape, active transport, multimodality...
Ključne besede: urban mobility, bicycle, urban landscape, active transport, multimodality
Objavljeno: 29.08.2019; Ogledov: 652; Prenosov: 46
.pdf Polno besedilo (1,85 MB)

Uporaba biometana za transport v sistemu koto
Gregor Drago Zupančič, Mario Panjicko, Goran Lukić, Lea Lavrič, Marko Verbič, elaborat, predštudija, študija

Najdeno v: ključnih besedah
Ključne besede: Bioplin, Biometan, Transport
Objavljeno: 04.03.2020; Ogledov: 612; Prenosov: 0
.pdf Polno besedilo (1,89 MB)

Molecular alignment on graphene surface determines transport properties of graphene/organic semiconductor transistors
Gvido Bratina, Egon Pavlica, Vadym Tkachuk, 2020, izvirni znanstveni članek

Opis: Graphene field-effect transistor structures were used to investigate the role of molecular alignment on charge transport properties of heterostructures comprising a single-layer graphene and variable thickness of N,N′-bis(n-octyl)-(1,7&1,6)-dicyanoperylene-3,4:9,10-bisdicarboximide (PDI8-CN2) - an n-type organic semiconductor. Our atomic force microscopy data show that under selected growth conditions PDI8-CN2 grows in a layer-by-layer fashion up to a second monolayer. The first layer comprises flat-lying molecules, whereas the molecules in the second layer orient themselves in an upright orientation. Transconductance measurements show that the flat-lying molecules have little effect on the position of the Fermi level in graphene. Upright oriented molecules in the second layer instead, have a strong effect as to neutralize native p-type doping of graphene and cause a shift of charge-neutrality level towards the Dirac point. We interpret such behavior in terms of different orientation of the surface dipole on layers with different molecular orientations. At the same time the overall mobility of the charge carriers reaches values exceeding 3000 cm2/Vs.
Najdeno v: ključnih besedah
Ključne besede: organski polprevodniki, grafen, transport električnega naboja
Objavljeno: 13.10.2020; Ogledov: 190; Prenosov: 0
.pdf Polno besedilo (2,64 MB)

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