1. Fuel conservation for launch vehicles: Falcon Heavy case studyPrimož Jozič, Aleksander Zidanšek, Robert Repnik, 2020, izvirni znanstveni članek Opis: Space exploration has recently been growing at an increasing pace and has caused a significant burden to the environment, in particular, during the launch of rockets, when a large amount of fuel is burned and the exhaust gases are released in the air. For this case study, we selected the SpaceX Falcon Heavy reusable heavy-lift launch vehicle, which is one of the most promising rockets for the low-cost lifting of heavy payloads into orbit and beyond. We evaluated several strategies for optimisation of fuel consumption and for minimisation of environmental impact during launch through the atmosphere for the case of its first launch on February 6, 2018, when the rocket carried a red Tesla Roadster with a "Starman" in the direction toward Mars. In addition to the flight plan and Newtonian equations of motion, we have taken into account the thermodynamic properties of the rocket engines. Results are similar but slightly different if one minimises the total fuel consumption for the desired flight plan or if one minimises the environmental pollution during the initial stage of the launch through the atmosphere. The same methodology can be extended for launches in other directions including the Earth orbit and the Moon. Ključne besede: fuel conservation, heavy-lift launch vehicles, environmental impact Objavljeno v DKUM: 24.01.2025; Ogledov: 0; Prenosov: 2
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2. Review of bioplastics characterisation by terahertz techniques in the view of ensuring a circular economyAndreja Abina, Tjaša Korošec, Uroš Puc, Aleksander Zidanšek, 2023, pregledni znanstveni članek Opis: The increasing scarcity of natural resources, worsening global climate change, environmental degradation, and rising demand for food are forcing the biotechnology and plastics industries to seek and apply circular economy models that would lead to a sustainable transition in the production and use of bioplastics. Circular economy models can improve the economic productivity of bio-based plastics and have a positive impact on the environment by reducing conventional plastic waste and the consumption of petrochemical feedstocks for plastic production. In addition, some agricultural wastes that have the potential to be used as bioplastics can be reused. Terahertz (THz) systems are already used in the plastics and rubber industries for non-destructive testing, detection, imaging, and quality control. Several reports have highlighted the potential applications of THz spectroscopy and imaging in polymer analysis and plastics characterisation. This potential is even greater with chemometric methods and artificial intelligence algorithms. In this review, we focus on applications that support the transformation of the biotechnology sector to the circular economy, particularly via the transition from conventional plastics to bioplastics. In this review, we discuss the potential of THz systems for the characterisation and analysis of bioplastics and biopolymers. The results of previous studies on biopolymers in the THz frequency range are summarised. Furthermore, the potential of using artificial intelligence approaches such as machine learning as advanced analytical methods in THz spectroscopy and imaging, in addition to the conventionally used chemometric methods, is discussed. The results of this review highlight that THz technology can contribute to closed technological circles in important areas of biotechnology and the related plastics and rubber industries. Ključne besede: terahertz spectroscopy, terahertz imaging, circular economy, biopolymer, biotechnology, bioplastics Objavljeno v DKUM: 16.04.2024; Ogledov: 354; Prenosov: 189
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3. Analytical gas sensing in the terahertz spectral rangeAndreja Abina, Uroš Puc, Mojca Jazbinšek, Aleksander Zidanšek, 2023, izvirni znanstveni članek Opis: Exploiting the terahertz (THz) part of the electromagnetic spectrum is attracting attention in various scientific and applied disciplines worldwide. THz technology has also revealed its potential as an effective tool for gas analysis in astronomy, biomedicine and chemical analysis. Recently, it has also become important in environmental applications for monitoring hazardous and toxic gases in the atmosphere. This paper gives an overview of THz gas detection analytical methods for environmental and biomedical applications, starting with a brief introduction to THz technology and an explanation of the interaction of THz radiation with gaseous species and the atmosphere. The review focuses on several gaseous species and groups of air pollutants that have been or can be analysed by THz spectrometry. The review concludes that different but complementary THz detection methods allow unique detection, identification and quantification of gaseous and particulate air pollutants with high selectivity, specificity and sensitivity. THz detection methods also allow further technological improvements and open new application possibilities. Ključne besede: terahertz spectroscopy, gas sensing, air pollution, environmental monitoring Objavljeno v DKUM: 28.03.2024; Ogledov: 205; Prenosov: 18
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4. Urinary metabolic biomarker profiling for cancer diagnosis by terahertz spectroscopy : review and perspectiveAndreja Abina, Tjaša Korošec, Uroš Puc, Mojca Jazbinšek, Aleksander Zidanšek, 2023, pregledni znanstveni članek Opis: In the last decade, terahertz (THz) technologies have been introduced to the detection, identification, and quantification of biomolecules in various biological samples. This review focuses on substances that represent important biomarkers in the urine associated with various cancers and their treatments. From a diagnostic point of view, urine liquid biopsy is particularly important because it allows the non-invasive and rapid collection of large volumes of samples. In this review, the THz spectral responses of substances considered metabolic biomarkers in urine and obtained in previous studies are collected. In addition, the findings from the relatively small number of prior studies that have already been carried out on urine samples are summarised. In this context, we also present the different THz methods used for urine analysis. Finally, a brief discussion is given, presenting perspectives for future research in this field, interpreted based on the results of previous studies. This work provides important information on the further application of THz techniques in biomedicine for detecting and monitoring urinary biomarkers for various diseases, including cancer. Ključne besede: terahertz spectroscopy, urinary biomarkers, metabolic biomarkers, cancer diagnostics, biomolecules, non-invasive detection, biomedical detection Objavljeno v DKUM: 14.03.2024; Ogledov: 212; Prenosov: 32
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5. Transformation of the RESPO decision support system to higher education for monitoring sustainability-related competenciesAndreja Abina, Bojan Cestnik, Rebeka Kovačič Lukman, Sara Zavernik, Matevž Ogrinc, Aleksander Zidanšek, 2023, izvirni znanstveni članek Opis: A result-oriented engagement system for performance optimisation (RESPO) has been developed to systematically monitor and improve the competencies of individuals in business, lifelong learning and secondary schools. The RESPO expert system was transferred for use in higher education institutions (HEIs) based on successful practical application trials. The architecture and functionality of the original RESPO expert system have been transformed into a new format that will collect information on the required competencies and the available educational programmes to help students effectively develop competencies through formal and non-formal education. First, the initial version of the RESPO system and its functionality were tested on a selected group of students and higher education staff to validate and improve its effectiveness for the needs of HEIs. This paper summarises the key findings and recommendations of the validators for transforming the RESPO application into an application for HEIs. In addition, the selection of competencies in the RESPO application database has been adapted to align with selected study programmes and the need to develop sustainability-related competencies. These findings can support professionals working in higher education institutions in developing students’ future competencies and fostering the targeted use of learning analytics tools. Ključne besede: higher education, competencies development, decision support, STEM education, sustainability Objavljeno v DKUM: 02.08.2023; Ogledov: 346; Prenosov: 20
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6. Decision support concept for improvement of sustainability-related competencesAndreja Abina, Tanja Batkovič, Bojan Cestnik, Adem Kikaj, Rebeka Kovačič Lukman, Maja Kurbus, Aleksander Zidanšek, 2022, izvirni znanstveni članek Opis: In this paper, we derived competences from previously developed competence models, ensuring the effective use of advanced technologies in future factories to improve the sustainability of their business models and strategies. Based on the analysis of the Hogan competence model and competence models for sustainability and leadership, we compiled a selection of competences for digitalisation, automation, robotics, artificial intelligence, and soft competences such as emotional intelligence and cultural literacy. We also included competences required for sustainability, corporate social responsibility, and circular economy. The selected competences formed the core for the conceptual development of a decision support tool for the individualised selection of training for employees. The concept was tested in customised training to improve employees’ skills and motivation for lifelong learning at the selected industrial partner. The developed assessment algorithm was used to monitor the progress of individual employees’ skills development before and after their training participation. The results of the assessment help human resource departments make decisions for selecting the most effective and optimal training for employees to improve their sustainability-related competences. Such a systematic approach can improve and evaluate competences that companies need to transition to a circular economy. Ključne besede: circular economy, sustainability, competence development, employee training plan, decision support Objavljeno v DKUM: 26.07.2023; Ogledov: 469; Prenosov: 64
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7. Modeliranje vlečne sile pri oranju z nevronsko mrežoMartin Kraner, 2015, diplomsko delo Opis: V uvodu sem opisal, zakaj sem se odločil za izdelavo nevronske mreže za izračun sil pri oranju. V nadaljevanju sem predstavil fizikalni proces pri oranju. Opisal sem enostaven približek pluga ter vlečne sile, ki se pojavljajo pri oranju, torej vlečno silo na plužno telo, lemež in rezilo. Nato sem opisal zgradbo nevronske mreže in uporabo modela nevronske mreže. Da bi lahko izračunali sile pri danih parametrih, sem nevronsko mrežo učil iz podatkov pridobljenih iz literature. Prav tako sem v nadaljevanju naredil preizkus s podatki oziroma meritvami iz literature. Nato sem primerjal rešitve in dobil zanimive rezultate, ki se jih lahko še dodela z vnovičnim učenjem nevronske mreže!
Diplomska naloga tako predstavlja teoretični uvod k izdelavi učinkovite aplikacije za kmetovalce in proizvajalce plužnih teles za izračun sil na plužna telesa pri izbranih parametrih! Ključne besede: plug, plužno telo, nevronska mreža, sile na plužno telo Objavljeno v DKUM: 27.07.2015; Ogledov: 1848; Prenosov: 160
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8. NAPRAVA ZA DOLOČANJE SPECIFIČNE TOPLOTNE PREVODNOSTI TRDNIN S KONTROLO TEMPERATURE ZRAKA NA MEJNIH PLOSKVAHNejc Duh, 2014, diplomsko delo Opis: Meritve toplotne prevodnosti trdnin so zahtevne, saj k prenosu toplote prispevajo prevajanje, konvekcija in sevanje. Izdelali smo merilnik, kjer lahko vpliv konvekcije in sevanja minimiziramo. Merilnik je sestavljen iz dveh izoliranih zra?nih komor, med kateri postavimo merjenec. Temperaturo komor reguliramo z bakrenim spiralnim grelnikom, skozi katerega te?e voda. Specifi?no toplotno prevodnost dolo?imo z meritvijo masnih pretokov vode, ki segreva zrak v komori z visoko temperaturo in ohlaja zrak v komori z nizko temperaturo, temperaturnih razlik vtekajo?e in iztekajo?e vode v obeh komorah ter temperaturne razlike med komorama. Ključne besede: toplotna prevodnost, toplotni tok, naprava za določanje specifične toplotne prevodnosti trdnin, termodinamika Objavljeno v DKUM: 23.10.2014; Ogledov: 2050; Prenosov: 145
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9. BLACK-SCHOLESOV MODEL VREDNOTENJA OPCIJDamir Najvirt, 2010, diplomsko delo Opis: V diplomski nalogi obravnavam Black-Scholesov model vrednotenja opcij, ki sta ga leta 1973 razvila Fisher Black in Myron Scholes. Black-Scholesov model je primeren za vrednotenje več vrst opcij, vendar pa v praksi prihaja do velikih razhajanj med vrednostjo opcije izračunano po Black-Scholesovem modelu in tržno ceno opcije. To razhajanje je že vrsto let podlaga raziskav, v katere se vključujejo tudi matematiki in fiziki. S stališča popularizacije fizike je predvsem zanimiva predpostavka modela, da je gibanje vrednosti delnic slučajen proces podoben difuziji, tako da lahko Black-Scholesovo enačbo rešimo po analogiji z difuzijsko enačbo. Ključne besede: Brownovo gibanje, Stohastični procesi, Wienerjev proces, opcije, izvedeni finančni instrumenti, Black-Scholesov model, nestanovitnost, difuzija, Mertonov model difuzije s skoki. Objavljeno v DKUM: 11.11.2010; Ogledov: 4614; Prenosov: 469
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10. FIZIKALNO OZADJE KLIMATSKIH MODELOV IN UPORABA PRI POUKU FIZIKEMateja Stermšek, 2009, diplomsko delo Opis: V zadnjem stoletju se je povprečna temperatura na Zemlji dvignila za 0,7 K. Segrevanje atmosfere je odvisno od mnogih parametrov. V diplomskem delu sem študirala fizikalno ozadje klimatskih modelov in pripravila predlog za uporabo pri pouku fizike.
Najprej sem opisala naravne pojave, ki vplivajo na segrevanje atmosfere. Nato sem opisala fizikalne osnove klimatskih modelov ter prvi preprost Fourierev model.
V osrednjem delu diplome sem izračunala povprečno temperaturo na Zemlji pri štirih različnih pogojih:
- Zemlja brez atmosfere
- Zemlja z enakomerno atmosfero
- Zemlja obdana z zrakom
- Zemlja poraščena z gozdom.
Pokazala sem, kako koncentracije ogljikovega dioksida in ostalih toplogrednih plinov vplivajo na emisivnost in na povprečno temperaturo Zemljine atmosfere.
Izračunane modele sem predstavila z računalniškim programom »Spreminjanje temperature«, ki računa povprečno temperaturo na Zemlji v odvisnosti od emisivnosti in je primeren za uporabo pri pouku fizike v šoli.
Ključne besede: Klima, energijsko ravnovesje, gozd, povprečna temperatura, topla greda Objavljeno v DKUM: 17.11.2009; Ogledov: 2386; Prenosov: 185
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