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Abstract: Diplomsko delo se osredotoča na raziskovanje ene najpomembnejših transformacij v sodobni avtomobilski industriji – prehoda na električna vozila in trajnostno mobilnost. Avtomobilska industrija se sooča z velikimi pritiski za zmanjšanje emisij toplogrednih plinov, zaradi česar so proizvajalci avtomobilov prisiljeni spremeniti svoje poslovne modele, da ostanejo konkurenčni in relevantni na trgu. V tem kontekstu smo v tem delu preučili podjetje Volkswagen, enega izmed vodilnih svetovnih proizvajalcev avtomobilov, ki se je prav tako znašel na tej prelomni točki. Volkswagen se je po tej točki znašel na položaju, kjer je bila sprememba nujna za ponovno pridobitev zaupanja potrošnikov in izboljšanje svoje tržne pozicije. Podjetje se je odzvalo z ambiciozno strategijo prehoda na električna vozila, ki vključuje visoke investicije v raziskave in razvoj, vzpostavitev gigatovarn za proizvodnjo baterij ter preoblikovanje svoje ponudbe vozil. V središču te strategije je bila uvedba serije električnih vozil ID, ki so ključnega pomena za prihodnjo rast in uspešnost podjetja. V raziskavi smo analizirali, kako so te inovacije v poslovnem modelu vplivale na Volkswagnovo konkurenčnost, finančne kazalnike in tržni položaj. Ugotovili smo, da je podjetje s temi spremembami ne le uspelo obdržati svojo tržno pozicijo, temveč jo je tudi okrepilo, kar se kaže v povečanju prodaje električnih vozil, izboljšanju bruto marže. Prehod na trajnostno mobilnost je Volkswagnu omogočil, da se prilagodi novim tržnim razmeram in se postavi kot pionir na področju trajnostnih tehnologij. Diplomsko delo prav tako opozarja na nekatere ključne izzive, s katerimi se Volkswagen in širša avtomobilska industrija soočata pri tem prehodu. Mednje sodijo visoki stroški prehoda na nove tehnologije, negotovosti glede prihodnje regulative ter potreba po hitrem prilagajanju na digitalizacijo in avtonomno vožnjo. Kljub tem izzivom delo izpostavlja, kako lahko podjetja z inovativnimi poslovnimi modeli ne le preživijo, temveč tudi uspevajo v dobi disruptivnih sprememb.
Keywords: Poslovni model, inovacija, Volkswagen, avtomobilska industrija
Published in DKUM: 10.09.2024; Views: 38; Downloads: 24
Full text (1,71 MB)

Abstract: Type 2 diabetes mellitus is a complex multifactorial disease of epidemic proportions. It involves genetic and lifestyle factors that lead to dysregulations in hormone secretion and metabolic homeostasis. Accumulating evidence indicates that altered mitochondrial structure, function, and particularly bioenergetics of cells in different tissues have a central role in the pathogenesis of type 2 diabetes mellitus. In the present study, we explore how mitochondrial dysfunction impairs the coupling between metabolism and exocytosis in the pancreatic alpha and beta cells. We demonstrate that reduced mitochondrial ATP production is linked with the observed defects in insulin and glucagon secretion by utilizing computational modeling approach. Specifically, a 30-40% reduction in alpha cells' mitochondrial function leads to a pathological shift of glucagon secretion, characterized by oversecretion at high glucose concentrations and insufficient secretion in hypoglycemia. In beta cells, the impaired mitochondrial energy metabolism is accompanied by reduced insulin secretion at all glucose levels, but the differences, compared to a normal beta cell, are the most pronounced in hyperglycemia. These findings improve our understanding of metabolic pathways and mitochondrial bioenergetics in the pathology of type 2 diabetes mellitus and might help drive the development of innovative therapies to treat various metabolic diseases.
Keywords: pancreatic endocrine cells, mathematical model, mitochondrial dysfunction, cellular bioenergetics, diabetes, glucagon, insulin
Published in DKUM: 03.09.2024; Views: 42; Downloads: 2
Full text (1,63 MB)
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Abstract: This in-depth study explores the intricate dynamics of reflective materials, emphasizing their impact on the indoor thermal environment and urban heat island (UHI) mitigation. Examining diffuse highly reflective (DHR), general reflective (GR), and retro-reflective (RR) materials on a simplified building model during summer days, the research utilizes outdoor experiments to analyze air and surface temperatures, as well as solar radiation. Prioritizing key metrics—mean radiant temperature (MRT), operative temperature (OT), and solar reflectance (ρ)—the study uncovers nuanced distinctions in DHR, GR, and RR materials. Solar reflectance calculations consistently show higher values for DHR and RR materials compared to GR material, highlighting reflectance's pivotal role in influencing surface temperatures and indoor thermal environment. When evaluating the impact of exterior wall materials on building temperatures, RR material with a 76% reflectance performs similarly to DHR material (82%). Notably, with a 6% lower reflectance in RR, the temperature contrast between external and internal walls is only about 1.5 °C at its maximum, underscoring RR's effectiveness as an outer wall material for UHI mitigation and building energy conservation, surpassing both DHR and GR materials.
Keywords: urban heat island, reflective materials, indoor thermal environment, solar reflectance, simplified building model
Published in DKUM: 23.08.2024; Views: 105; Downloads: 3
Full text (4,82 MB)

Abstract: In order to ensure efficient wastewater treatment and seawater desalination, adequate modeling and optimization of the forward osmosis (FO) process has the potential to be very helpful. This paper deals with the FO model parameters calibration and FO process optimization by a gradient-based optimization method. For this purpose, an upgraded FO model, which involves temperature- and agent-dependent parameters, was developed. The FO model calibration was done using NaCl as agents in draw solution, while MgCl2 was used for model validation. The agreements between simulated and measured FO performance were satisfactory; relative index of agreement are higher than 0.99. By using the proposed FO model, the optimization of FO process conditions was performed with various definitions of the objective and constraint functions. In case of maximizing the water flux, minimizing reverse solute flux, and fulfilling the required constraints, the ratio of water flux and reverse solute flux increased up to 40 % for NaCl and up to 20 % for MgCl2; meanwhile the effective osmotic pressure difference was improved 2-times for NaCl and up to 3.8-times for MgCl2. The optimization process proved to be stable and efficient and can easily be adapted or upgraded for more complex dynamic FO modeling.
Keywords: forward osmosis, modeling, model and process parameters, calibration procedure, gadient-based optimization
Published in DKUM: 23.08.2024; Views: 62; Downloads: 8
Full text (12,72 MB)

Abstract: Tannins represent secondary plant metabolites that are used to control bacterial populations by chelation of essential metal ions. Their presence in food also affects the bioavailability of iron. This study investigates the influence of ellagitannins (vescalin, castalin, vescalagin, castalagin) structure and pH on the stoichiometry and formation constants of ellagitannin-Fe(II) coordination compounds. We demonstrated that ellagitannins are stable for at least one hour at pH values lower than 7.25. The spectra of neutral compounds were measured and explained with the help of TDDFT calculations. Furthermore, the pH-dependence of the ellagitannins UV–Vis spectra was examined to obtain insight into their protolytic equilibrium. Using Job’s method in the pH range 3.50–5.51, the stoichiometry of the formed ellagitannin-Fe(II) ions complexes was determined. A model explaining interactions between ellagitannins and Fe(II) ions, that took into account the protolytic equilibrium of ellagitannins, was fitted globally to all four Job plots, whereby the corresponding formation constants were obtained.
Keywords: Ellagitannins, Fe(II) ions chelation, protolytic equilibrium, Job’s method, model fitting
Published in DKUM: 22.08.2024; Views: 50; Downloads: 1
Full text (3,98 MB)