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1.
2.
The importance of depropagation in free radical co-polymerization of itaconates : PhD Thesis
Tomaž Pirman, 2024, doctoral dissertation

Abstract: Biobased monomers offer a means to enhance the sustainability of acrylic resins, which are traditionally manufactured from acrylate and methacrylate monomers derived from petrochemical sources. However, utilizing renewable feedstocks for these monomers is currently not economically viable, necessitating the exploration of alternative pathways for producing sustainable acrylic resins. Itaconates, which are produced via fermentation, share a similar structure with conventional monomers, making it possible to achieve comparable polymer properties without significantly changing production processes. However, itaconates have limitations: they depropagate at lower temperatures and exhibit much slower polymerization rates than conventional methacrylates during homopolymerization. This study explores the copolymerization of itaconates with acrylates under standard commercial conditions as a promising approach to address these challenges. The copolymerization of dibutyl itaconate (DBI) with butyl acrylate (BA) is examined in detail. Initial investigations involved batch homopolymerizations of DBI, varying monomer and initiator concentrations, solvent types, and reaction temperatures to validate known propagation and termination kinetics and to gain a deeper understanding of DBI depropagation. Conversion rates and molecular weight distributions were measured using 1H NMR and size exclusion chromatography, respectively. These results were used to refine the representation of depropagation kinetics by fitting the data to a comprehensive kinetic model of DBI homopolymerization, implemented in the PREDICI software, with additional kinetic parameters sourced from recent literature. Subsequently, BA was employed as a highly reactive, non-depropagating comonomer in a batch system to mitigate the strong depropagation and slow polymerization rates of DBI. Experiments were conducted with varying initial monomer concentrations and compositions at different temperatures. In addition to demonstrating that BA significantly enhances the polymerization rate, the data provided initial estimates of reactivity ratios for acrylate-itaconate copolymerization. Furthermore, semi-batch copolymerization experiments were performed with varying monomer compositions under starved feed conditions and elevated temperatures, reflecting typical commercial practices. These trials indicated that resins containing up to 50% itaconate are feasible for production, offering the potential to greatly increase the sustainable content of acrylic polymer resins. Finally, a comprehensive kinetic model for BA/DBI copolymerization, incorporating itaconate depropagation and acrylate backbiting, was developed using the PREDICI software. The model's predictions are compared to experimental batch and semi-batch conversion profiles, polymer molar mass distributions, and comonomer composition drift profiles. This comparison enhances the understanding of the system and provides a tool for further process development and optimization of operating conditions.
Keywords: Itaconates, Bio-based monomer, Kinetic modeling, Sustainable acrylic resins, Depropagation
Published in DKUM: 12.02.2025; Views: 0; Downloads: 1
.pdf Full text (5,03 MB)

3.
Zunanja politika kneza Pavla : jugoslovansko približevanje Nemčiji in Italiji v tridesetih letih 20. stoletja
Žana Plejić, 2024, master's thesis

Abstract: V magistrskem delu je obravnavana zunanja politika kneza Pavla Karađorđevića, ki je leta 1934 po atentatu na kralja Aleksandra prevzel funkcijo regenta mladoletnega Petra II. Karađorđevića. Knez Pavle je skupaj z dr. Ivom Perovićem in dr. Radenkom Stankovićem postal eden izmed treh regentov, vendar je bil on tisti, ki je dejansko vodil državo. Njegova zunanja politika je slonela na izboljševanju odnosov z Nemčijo in Italijo, kar je bilo velikokrat v nasprotju z njegovimi osebnimi prepričanji, saj je bil sam probritansko usmerjen. Poseben poudarek v magistrskem delu je na njegovem odnosu in delovanju do Nemčije in Italije. Naloga bo vsebinsko razdeljena na dva večja sklopa. Prvi sklop se osredotoča na čas, ko je funkcijo ministrskega predsednika in zunanjega ministra zasedal pronemško usmerjeni Milan Stojadinović, ki je odnose z Italijo pripeljal do najbolj pozitivne točke v času regentstva kneza Pavla, kar se najbolje odraža v podpisu pakta Ciano-Stojadinović. Drugi vsebinski sklop pa se bo osredotočal na čas, ko je bil ministrski predsednik Dragiša Cvetković ter zunanji minister Aleksandar Cincar-Marković. Ta čas so zaznamovali predvsem druga svetovna vojna ter Pavlovi poskusi Kraljevini Jugoslaviji zagotoviti nevtralnost, vendar je Jugoslavija 25. marca 1941 podpisala pristop k Trojnemu paktu. Ob pisanju naloge je bilo analizirano pisanje slovenskega konservativnega časnika Slovenec ter liberalnih časnikov Jutro ter Slovenski narod ter primarni objavljeni viri, ki jih hrani digitalni arhiv Združenih narodov. Analizirani so bili tudi objavljeni viri Yugoslavia, Political diaries 1918−1965 urednika Roberta Jarmana.
Keywords: Knez Pavle, Karađorđević, Kraljevina Jugoslavija, Italija, Nemčija
Published in DKUM: 10.02.2025; Views: 0; Downloads: 5
.pdf Full text (1,14 MB)

4.
Izboljšave odpornosti jedrskih elektrarn na zunanje dogodke kot posledica izkušenj s cunamijem v jedrski elektrarni Fukušima : diplomsko delo
Tino Bajc, 2024, undergraduate thesis

Abstract: Leta 2011 je prišlo do jedrske nesreče v Fukušimi, ki je pustila katastrofalne posledice. Kljub strogim varnostnim standardom so bile prisotne ranljivosti, kot so nezadostna zaščita pred cunamiji, ranljiv sistem za hlajenje ter pomanjkljiva usposobljenost za obvladovanje ekstremnih dogodkov. Novi varnostni standardi zahtevajo razvoj naprednih tehnologij za pasivno hlajenje in zaščito pred naravnimi nesrečami ter implementacija pametnih sistemov za nadzor in upravljanje v realnem času. Prav tako je pomembno, da se krepi varnostna kultura in mednarodno sodelovanje ter se redno ocenjujejo tveganja in posodabljajo krizni načrti. Z ustreznimi tehničnimi izboljšavami lahko zmanjšamo tveganja in zagotovimo varno prihodnost jedrske energije.
Keywords: jedrska energija, odpornost na zunanje dogodke, varnostne posodobitve, nadgradnja postopkov za obvladovanje tveganj, jedrska varnost
Published in DKUM: 10.02.2025; Views: 0; Downloads: 2
.pdf Full text (2,09 MB)

5.
Razvoj grafičnega uporabniškega vmesnika za spletno prodajo prilagodljivih izdelkov : magistrsko delo
Luka Kobale, 2024, master's thesis

Abstract: Spletna prodaja prilagodljivih izdelkov je zelo zahtevna, saj mora kupec razumeti omejitve prilagajanj ter izgled in ceno prilagojenega izdelka. To težavo danes rešujejo blagovne znamke s pomočjo konfiguratorjev, katerih razvoj je zahteven in dolgotrajen. Kot rešitev te težave smo razvili platformo za enostavnejši razvoj konfiguratorjev. V magistrski nalogi se osredotočamo na razvoj grafičnega uporabniškega vmesnika, ki omogoča predstavitev različnih konfiguratorjev glede na nastavitve, ki jih vnesemo kot vhodni podatek.
Keywords: Three.js, Angular, spletna aplikacija, TypeScript, arhitektura programske opreme
Published in DKUM: 06.02.2025; Views: 0; Downloads: 0

6.
Effect of Lactobacillus spp. on adhesion, invasion, and translocation of Campylobacter jejuni in chicken and pig small-intestinal epithelial cell lines
Maja Šikić Pogačar, Tomaž Langerholc, Dušanka Mičetić-Turk, Sonja Smole Možina, Anja Klančnik, 2020, original scientific article

Abstract: Background : Campylobacter spp. are a major cause of bacterial food-borne diarrhoeal disease. This mainly arises through contamination of meat products during processing. For infection, Campylobacter spp. must adhere to epithelial cells of the mucus layer, survive conditions of the gastrointestinal tract, and colonise the intestine of the host. Addition of probiotic bacteria might promote competitive a dhesion to epithelial cells, consequently reducing Campylobacter jejuni colonisation. Effect of Lactobacillus spp. (PCS20, PCS22, PCS25, LGG, PCK9) on C. jejuni adhesion, invasion and translocation in pig (PSI cl.1) and chicken (B1OXI) small-intestine cell lines, as well as pig enterocytes (CLAB) was investigated. Results : Overall, in competitive adhesion assays with PSI cl.1 and CLAB cell monolayers, the addition of Lactobacillus spp. reduced C. jejuni adherence to the cell surface, and negatively affected the C. jejuni invasion. Interestingly, Lactobacillus spp. significantly impaired C. jejuni adhesion in three-dimensional functional PSI cl.1 and B1OXI cell models. Also, C. jejuni did not translocate across PSI cl.1 and B1OXI cell monolayers when co-incubated with probiotics. Among selected probiotics, Lactobacillus rhamnosus LGG was the strain that reduced adhesion efficacy of C. jejuni most significantly under co-culture conditions. Conclusion : The addition of Lactobacillus spp. to feed additives in livestock nutrition might be an effective novel strategy that targets Campylobacter adhesion to epithelial cells, and thus prevents colonisation, reduces the transmission, and finally lowers the incidence of human campylobacteriosis.
Keywords: Campylobacter jejuni, Lactobacillus spp., chicken and pig cell line, adhesion, invasion, translocation
Published in DKUM: 06.02.2025; Views: 0; Downloads: 0
.pdf Full text (1,80 MB)
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7.
Brezizgubno stiskanje rastrskih slik z uporabo genetskega algoritma
Tomaž Klobučar, 2025, master's thesis

Abstract: V magistrskem delu je predstavljena uporaba genetskega algoritma za brezizgubno stiskanje rastrskih slik. Poudarek je na kombiniranju genetskega algoritma z različnimi tehnikami stiskanja podatkov, vključno z aritmetičnim kodiranjem, metodo RLE (angl. Run Length Encoding) in Huffmanovim kodiranjem. Podrobno je opisano teoretično ozadje genetskega algoritma in njegovih osnovnih postopkov, kot so selekcija, križanje in mutacija. Prav tako je predstavljena implementacija genetskega algoritma, kodirnika in dekodirnika. Opravljene so bile analize vhodnih parametrov kodeka, stiskanja splošnih in risanih slik, vpliva napovedi genetskega algoritma na stopnjo stiskanja, vpliva pretvorbe barvnega prostora na stopnjo stiskanja ter analiza časovne zahtevnosti. Rezultati so pokazali, da predlagan kodek doseže stopnjo stiskanja primerljivo z izbranimi formati, njegova učinkovitost stiskanja pa se izboljša z uporabo pretvorbe barvnega prostora.
Keywords: brezizgubno stiskanje slik, risane slike, genetski algoritem, Huffmanovo kodiranje, aritmetično kodiranje, RLE
Published in DKUM: 06.02.2025; Views: 0; Downloads: 2
.pdf Full text (7,00 MB)

8.
Comparative study of different polymeric binders in electrochemical CO reduction
Noémi V. Galbicsek, Attila Kormányos, Gergely Ferenc Samu, Mohd M. Ayyub, Tomaž Kotnik, Sebastijan Kovačič, Csaba Janáky, Balázs Endrődi, 2024, original scientific article

Abstract: Electrochemical reduction of carbon monoxide offers a possible route to produce valuable chemicals (such as acetate, ethanol or ethylene) from CO2 in two consecutive electrochemical reactions. Such deeply reduced products are formed via the transfer of 4–6 electrons per CO molecule. Assuming similar-sized CO2 and CO electrolyzers, 2–3-times larger current densities are required in the latter case to match the molar fluxes. Such high reaction rates can be ensured by tailoring the structure of the gas diffusion electrodes. Here, the structure of the cathode catalyst layer was systematically varied using different polymeric binders to achieve high reaction rates. Simple linear polymers, bearing the same backbone but different functional groups were compared to highlight the role of different structural motifs. The comparison was also extended to simple linear, partially fluorinated polymers. Interestingly, in some cases similar results were obtained as with the current state-of-the-art binders. Using different surface-wetting characterization techniques, we show that the hydrophobicity of the catalyst layer─provided by the binder─ is a prerequisite for high-rate CO electrolysis. The validity of this notion was demonstrated by performing CO electrolysis experiments at high current density (1 A cm–2) for several hours using PVDF as the catalyst binder.
Keywords: electrochemical CO reduction, polymeric binders, carbon monoxide
Published in DKUM: 04.02.2025; Views: 0; Downloads: 2
.pdf Full text (3,55 MB)

9.
Digital transformation reduces costs of the paints and coatings development process
Tomaž Kern, Eva Krhač Andrašec, Benjamin Urh, Marjan Senegačnik, 2020, original scientific article

Abstract: An essential characteristic of the new product development process is to develop a new marketable product in the shortest possible time with the lowest reasonable costs. Therefore, the key factor of the process is efficiency. The paints and coatings industry development process contain numerous laboratory tests to determine the appropriateness of new formulation. It is proven that digital transformation can reduce the number of laboratory tests and consequently shorten the throughput time of the development process. This raised the question of whether the faster development process also reduces the process’ cost, or they even increase due to information and communication technology implementation. Therefore, the research’s purpose was to determine whether reducing the number of laboratory tests, based on the implementation of information and communication technology (ICT), affects reducing costs in the paints and coatings development process. The conventional process and the redesigned process of paints and coatings development were used as the basis of the research. The comparative analysis of the costs incurred during the development process was made. The analysis compares the types and amount of incurred costs. The article proves that digital transformation has a significant impact on up to 48% on reducing costs of the paints and coatings development process.
Keywords: coatings industry, digital transformation, development process, process redesign, technical enabler, implementation cost, rentability threshold
Published in DKUM: 24.01.2025; Views: 0; Downloads: 3
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10.
Screening for diabetic retinopathy : a twelve-month review
Tomaž Gračner, 2020, original scientific article

Abstract: The purpose is to provide a twelve-month database review of screening for diabetic retinopathy (DR). A total of 1428 diabetes mellitus (DM) patients screened in 2017 were analyzed in a retrospective study. Retinal photographs were reviewed by an ophthalmologist for the presence and stage of DR, as well as for additional nondiabetic findings. The following grading categories of DR were used: without DR, mild non-proliferative DR (NPDR), moderate NPDR, severe nonproliferative NPDR, proliferative DR (PDR), clinically significant macular edema (CSME) and ungradable finding. Severe NPDR, PDR and CSME were classified as vision-threatening DR. Out of 1428 DM patients, 27 were diagnosed with type 1 DM and 1401 with type 2 DM, 353 of them had newly diagnosed type 2 DM. Without DR category was recorded in 85.2% of all eyes screened, 2.8% were ungradable, and 12% showed varying stages of DR. Vision-threatening DR was found in 2.8% and additional nondiabetic findings in 5.2% of all screened eyes. In the group of newly diagnosed type 2 DM, 92.5% of screened eyes were without DR, 3.1% were ungradable and 4.3% showed varying stages of DR. In the group of newly diagnosed type 2 DM, vision-threatening DR was recorded in 0.1% and additional nondiabetic finding in 5.7% of the eyes screened. In conclusion, a small proportion of screened DM patients with detected DR had vision-threatening DR.
Keywords: diabetes mellitus, diabetic retinopathy, screening, proliferative retinopathy, maculopathy
Published in DKUM: 22.01.2025; Views: 0; Downloads: 2
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