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71.
The new instrument using a TC–BC (total carbon–black carbon) method for the online measurement of carbonaceous aerosols
Martin Rigler, Luka Drinovec, Gašper Lavrič, Anastasia Vlachou, André S. H. Prévôt, Jean-Luc Jaffrezo, Iasonas Stavroulas, Jean Sciare, Judita Burger, Irena Krajnc, Janja Turšič, Anthony D. A. Hansen, Griša Močnik, 2020, izvirni znanstveni članek

Opis: We present a newly developed total carbon analyzer (TCA08) and a method for online speciation of carbonaceous aerosol with a high time resolution. The total carbon content is determined by flash heating of a sample collected on a quartz-fiber filter with a time base between 20 min and 24 h. The limit of detection is approximately 0.3 µg C, which corresponds to a concentration of 0.3 µg C m−3 at a sample flow rate of 16.7 L min−1 and a 1 h sampling time base. The concentration of particulate equivalent organic carbon (OC) is determined by subtracting black carbon concentration, concurrently measured optically by an Aethalometer®, from the total carbon concentration measured by the TCA08. The combination of the TCA08 and Aethalometer (AE33) is an easy-to-deploy and low-maintenance continuous measurement technique for the high-time-resolution determination of equivalent organic and elemental carbon (EC) in different particulate matter size fractions, which avoids pyrolytic correction and the need for high-purity compressed gases. The performance of this online method relative to the standardized off-line thermo-optical OC–EC method and respective instruments was evaluated during a winter field campaign at an urban background location in Ljubljana, Slovenia. The organic-matter-to-organic-carbon ratio obtained from the comparison with an aerosol chemical speciation monitor (ACSM) was OM/OC=1.8, in the expected range.
Najdeno v: osebi
Ključne besede: total carbon, aeroosl, black carbon, carbonaceous matter
Objavljeno: 17.08.2020; Ogledov: 1628; Prenosov: 51
.pdf Polno besedilo (226,45 KB)

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Short-range urban dispersion experiments using fixed and moving sources
Stephen E Belcher, Alison S Tomlin, James Tate, Marina K Neophytou, Rex E Britter, Fredrik Petterson, Iain R White, Graham Nickless, Catheryn S Price, Damien Martin, Dudley E. Shallcross, Janet F Barlow, Alan Robins, 2009, izvirni znanstveni članek

Opis: Four perfluorocarbon tracer dispersion experiments were carried out in central London, United Kingdom in 2004. These experiments were supplementary to the dispersion of air pollution and penetration into the local environment (DAPPLE) campaign and consisted of ground level releases, roof level releases and mobile releases; the latter are believed to be the first such experiments to be undertaken. A detailed description of the experiments including release, sampling, analysis and wind observations is given. The characteristics of dispersion from the fixed and mobile sources are discussed and contrasted, in particular, the decay in concentration levels away from the source location and the additional variability that results from the non-uniformity of vehicle speed.
Najdeno v: osebi
Ključne besede: dapple, perfluorocarbon, tracer, mobile source
Objavljeno: 18.07.2019; Ogledov: 1875; Prenosov: 0
.pdf Polno besedilo (265,68 KB)

75.
Application of beam deflection spectrometry for the determination of iron species in passive samplers exposed to Southern Ocean ice
Hanna Budasheva, Arne Bratkič, Martin Šala, Dorota Korte, Mladen Franko, 2021, prispevek na konferenci brez natisa

Najdeno v: osebi
Objavljeno: 02.12.2021; Ogledov: 582; Prenosov: 1
.pdf Polno besedilo (1,52 MB)
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76.
Anaerobic Co-Digestion of Ligno-Cellulosic degradation products - Wood Resin Residue from Tannin Production
Gregor Draago Zupančič, Mario Panjicko, Domagoj Eršek, Goran Lukić, Žiga Velišček, Martin Gojun, 2018, objavljeni znanstveni prispevek na konferenci

Opis: Tannin is a very versatile industrial material used for many applications. During tannin production, a residue is produced, which consists of 10 – 15 % sodium acetate solution with up to 10 % water-soluble wood resins by mass. Since it contains a high portion of acetate, it can be useful for anaerobic digestion to produce biomethane, whereas wood resins may exhibit inhibitory effects. In order to test the biodegradability of wood resin residue, several batch tests were performed with two approaches. In the first approach, co-digestion with corn-silage and animal waste was performed utilizing suspended biomass inoculum. In the second approach, co-digestion with pulp and paper wastewater was performed utilizing granular biomass inoculum. In the first approach, the results showed partial inhibition of degradation using mixtures of 25.6 % and total inhibition using 100.0 % of wood resin. Maximum biodegradability achieved was 83.4 %. In the second approach, the results showed partial inhibition of degradation using mixtures of 1.7 and 3.3 % of wood resin. Maximum biodegradability achieved was 64.3 %. Because the second approach enabled us to process larger quantities of wood resin (larger COD load), a pilot experiment of anaerobic co-digestion with pulp and paper wastewater was performed, utilising similar conditions to the considered full-scale treatment. The results showed COD degradation between 70.1 and 81.7 % and a potential increase in total produced biomethane of 36 – 39 %, with no significant adverse effects. Wood resin residue yielded 45 – 50 m3 of biomethane per tonne, which exhibits a good potential for biomethane production. If used for biomethane production in pulp and paper wastewater treatment, the valorisation value of the wood resin residue is between 54,500 € and 94,000 €, which makes the presented treatment also an economically viable option.
Najdeno v: osebi
Ključne besede: Anaerobic digestion, biomethane production, wood resin residue
Objavljeno: 11.03.2020; Ogledov: 2101; Prenosov: 0
.pdf Polno besedilo (666,01 KB)

77.
Prenova montažnega procesa v podjetju Agromehanika Kranj
Martin Hočevar, 2020, diplomsko delo

Opis: Podjetje Agromehanika v celoti prenavlja poslovne procese, v diplomskem delu pa smo se v okviru prenove proizvodnih procesov omejili na prenovo montažnega procesa. Podjetje se občasno srečuje s problemom predolgih dobavnih rokov, zato smo si zastavili ambiciozen cilj: skrajšati čas montaže za 30 %. Proučili smo teoretična dognanja, nato pa naredili analizo obstoječega stanja: izmerili in narisali velikost montažne delavnice, popisali potrebno opremo ter ugotovili razpoložljivo število montažnih delavcev pri obstoječem načinu montaže. Pridobili smo kosovnico za izbrani izdelek, potem pa merili čase posameznih operacij ter narisali in opisali zaporedje izvajanja le-teh. Sledilo je načrtovanje prenove montažnega procesa za izbrani proizvod. Projekt prenove montažnega procesa smo vodili s precedenčnim diagramom. Za oskrbo z vijačnim materialom smo uvedli sistem KANBAN. Ločili smo logistično in montažno funkcijo. Odločili smo se za ravno linijsko postavitev in uvedli izboljšave v procesu montaže. Rezultat prenove montažnega procesa za izbrani proizvod je bil znižanje časa montaže za 41,57 % v pilotni liniji brez dodatnih investicij in 64,25 % v predvideni liniji z dodatnimi investicijami. Prihranek časa pri delu montažnih delavcev smo ovrednotili tudi finančno. Prenova montažnega procesa podjetju zagotavlja končne proizvode, razpoložljive v krajšem času kot doslej. S tem je skrajšan dobavni rok, ki je kupcem ključnega pomena v času, ko pridobijo državne subvencije za razvoj kmetijstva, ki jih morajo črpati v predvidenem roku. Zato ima prenova montažnega procesa za podjetje multiplikativen pozitiven učinek, s katerim obdrži obstoječe stranke, s krajšimi dobavnimi časi pa morda pridobi tudi nove.
Najdeno v: osebi
Ključne besede: prenova, poslovni proces, proizvodni proces, montažni proces, vitka proizvodnja, sistem KANBAN, »ravno pravočasno«, linija, operacija, precedenčni diagram
Objavljeno: 28.10.2020; Ogledov: 1694; Prenosov: 70
.pdf Polno besedilo (1,42 MB)

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Effect of the Morphology of the High-Surface-Area Support on the Performance of the Oxygen-Evolution Reaction for Iridium Nanoparticles
Leonard Moriau, Marjan Bele, Živa Marinko, Francisco Ruiz-Zepeda, Gorazd Koderman, Martin Šala, Angelija Kjara Šurca, Janez Kovač, Iztok Arčon, Primož Jovanovič, Nejc Hodnik, Luka Suhadolnik, 2021, izvirni znanstveni članek

Opis: The development of affordable, low-iridium-loading, scalable, active, and stable catalysts for the oxygen-evolution reaction (OER) is a requirement for the commercialization of proton-exchange membrane water electrolyzers (PEMWEs). However, the synthesis of high-performance OER catalysts with minimal use of the rare and expensive element Ir is very challenging and requires the identification of electrically conductive and stable high-surface-area support materials. We developed a synthesis procedure for the production of large quantities of a nanocomposite powder containing titanium oxynitride (TiONx) and Ir. The catalysts were synthesized with an anodic oxidation process followed by detachment, milling, thermal treatment, and the deposition of Ir nanoparticles. The anodization time was varied to grow three different types of nanotubular structures exhibiting different lengths and wall thicknesses and thus a variety of properties. A comparison of milled samples with different degrees of nanotubular clustering and morphology retention, but with identical chemical compositions and Ir nanoparticle size distributions and dispersions, revealed that the nanotubular support morphology is the determining factor governing the catalyst’s OER activity and stability. Our study is supported by various state-of-the-art materials’ characterization techniques, like X-ray photoelectron spectroscopy, scanning and transmission electron microscopies, Xray powder diffraction and absorption spectroscopy, and electrochemical cyclic voltammetry. Anodic oxidation proved to be a very suitable way to produce high-surface-area powder-type catalysts as the produced material greatly outperformed the IrO2 benchmarks as well as the Ir-supported samples on morphologically different TiONx from previous studies. The highest activity was achieved for the sample prepared with 3 h of anodization, which had the most appropriate morphology for the effective removal of oxygen bubbles.
Najdeno v: osebi
Ključne besede: electrocatalysis, oxygen-evolution reaction, TiONx-Ir powder catalyst, iridium nanoparticles, anodic oxidation, morphology−activity correlation
Objavljeno: 04.01.2021; Ogledov: 1373; Prenosov: 0
.pdf Polno besedilo (6,36 MB)

80.
Multiresponsive nonvolatile memories based on optically switchable ferroelectric organic field-effect transistors
Martin Herder, Alex Dixon, Marco Carroli, Egon Pavlica, Stefan Hecht, Gvido Bratina, Emanuele Orgiu, Paolo Samorì, 2021, izvirni znanstveni članek

Opis: Organic transistors are key elements for flexible, wearable, and biocompatible logic applications. Multiresponsivity is highly sought‐after in organic electronics to enable sophisticated operations and functions. Such a challenge can be pursued by integrating more components in a single device, each one responding to a specific external stimulus. Here, the first multiresponsive organic device based on a photochromic–ferroelectric organic field‐effect transistor, which is capable of operating as nonvolatile memory with 11 bit memory storage capacity in a single device, is reported. The memory elements can be written and erased independently by means of light or an electric field, with accurate control over the readout signal, excellent repeatability, fast response, and high retention time. Such a proof of concept paves the way toward enhanced functional complexity in optoelectronics via the interfacing of multiple components in a single device, in a fully integrated low‐cost technology compatible with flexible substrates.
Najdeno v: osebi
Ključne besede: organic transistors, memory, time-dependent
Objavljeno: 11.03.2021; Ogledov: 1064; Prenosov: 0
.pdf Polno besedilo (281,34 KB)

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