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Quincke effect
No full textQuinckejev pojav je elektrohidrodinamični pojav, pri katerem se dielektrični delci v rahlo prevodni tekočini spontano začnejo vrteti, kadar jih izpostavimo zunanjemu električnemu polju. Če so delci v stiku s podlago, se ta rotacija prenese v kotaljenje. Preučevali smo steklene delce v raztopini natrijevega dioktilsulfosukcinata (AOT) v heksadekanu. Osredotočili smo se na obravnavo odvisnosti hitrosti kotaljenja od jakosti zunanjega električnega polja ter na analizo režima oscilirajočih delcev. Za potrebe raziskave smo vzpostavili eksperimentalni sistem z elektrodama iz stekla na katerih je bil nanešen indijev kositrov oksid (ITO, ang. indium tin oxide), ki je omogočal stabilno generiranje homogenega električnega polja. Gibanje več sto delcev smo analizirali s pomočjo optične mikroskopije in računalniškega sledenja pri različnih koncentracijah AOT in pri različnih jakostih električnega polja. Rezultate smo primerjali z obstoječim modelom odvisnosti hitrosti kotaljenja od jakosti zunanjega električnega polja ter z nadgrajenim modelom, ki smo ga razvili in upošteva odvisnost prevodnosti medija od električnega polja. Eksperimentalni podatki so se bolje prilagajali nadgrajenemu modelu na opazovanem intervalu električnih polj. Poleg kotaljenja smo sistematično preučili tudi oscilacijski režim obnašanja delcev. V tem režimu se delci izmenično premaknejo za približno eno dolžino svojega premera in nato za določen čas mirujejo. Ugotovili smo, da se povprečni čas mirovanja z naraščanjem jakosti polja zmanjšuje, hkrati pa se spreminja tudi oblika histograma porazdelitve teh časovnih intervalov. Poleg tega so pri električnih poljih pod 2 MV/m vršne hitrosti posameznih premikov pogosto presegle hitrosti enakomernega kotaljenja.The Quincke effect is an electrohydrodynamic phenomenon in which dielectric particles suspended in a weakly conductive liquid spontaneously begin to rotate when exposed to an external electric field. If the particles are in contact with a surface, this rotation results in rolling. We studied glass particles in a solution of the dioctyl sodium sulfosuccinate (AOT) in hexadecane, focusing on the dependence of the rolling velocity on the strength of the external electric field, as well as on the analysis of the oscillatory regime of the particles. For the purpose of the study, we established an experimental system with glass electrodes coated with indium tin oxide (ITO), which enabled the stable generation of a homogeneous electric field. The motion of several hundred particles was analyzed using optical microscopy and computer-based tracking, for different concentrations of AOT and at various electric field strengths. We compared the results with the existing model describing the dependence of the rolling velocity on the external electric field, as well as with the specific model we developed that takes into account the field-dependent conductivity of the medium. The experimental data showed a better fit to the specific model within the observed interval of electric field strengths. In addition to rolling, we systematically investigated the oscillatory regime of particle behavior. In this regime, the particles alternately move by approximately one particle diameter and then remain stationary for a certain time. We found that the average resting time decreases with increasing field strength, while the shape of the histogram of these time intervals also changes. Moreover, at electric field strengths below 2 MV/m, the maximum velocities of individual displacements often exceeded those of uniform rolling
Interaction between shallow centers and spin-active azafullerenes on hydrogenated and fluorinated diamond (001) surfaces
No full textThe interaction between surface-lying nitrogen-substituted fullerenes (radical azafullerene, ) with subsurface negative nitrogen-vacancy complexes () in diamond is investigated using first-principles calculations. We consider (2×1) reconstructed (001) oriented diamond surfaces with both H- and F-surface termination. The charge stability of when in close proximity to both the nearby surface and the spin active azafullerene is discussed, in the context of diamond band bending arising from surface-induced changes in electron affinity (EA). In the case of the hydrogenated surface, the system spin is quenched, yielding a negatively charged azafullerene () and neutrally charged as the most stable electronic configuration. In contrast, fluorinating the surface favors the negatively charged and conserves the neutrality and stabilizes uncompensated free spins. This opposing behaviour is attributed to surface charge doping emerging from different band bending effects associated with the surface EA. This study is consistent with experimentally observed photoluminescence quenching, and shows that surface passivation by fluorination could efficiently tackle the problem of charge transfer between adsorbed molecules and shallow NV centers
An optimal design method of hydrostatic turntable based on FPSO algorithm
No full textThe load capacity of hydrostatic turntables is predominantly governed by the design of oil pads. Optimizing oil pad parameters can substantially enhance turntable performance while reducing power consumption. This study introduces a fuzzy particle swarm optimization (FPSO) algorithm that incorporates compression factors into the particle swarm optimization (PSO) framework to optimize the parameters of oil pads. Reduce its power consumption by about 40 %, while the error between experimental and theoretical values is only 8 %. Compared with traditional PSO algorithms, FPSO converges more reliably in multiparametric environments.Nosilnost hidrostatičnih vrtljivih miz je v veliki meri odvisna od zasnove oljnih blazinic. Optimizacija parametrov oljnih blazinic lahko bistveno izboljša zmogljivost vrtljive mize ter hkrati zmanjša porabo energije. V tej študiji je predstavljen algoritem mehke optimizacije z rojem delcev (FPSO), ki v osnovno optimizacijo z rojem delcev (PSO) vpeljuje faktorje stisljivosti za optimizacijo parametrov oljnih blazinic. Rezultati optimizacije kažejo, da je rabo energije je mogoče zmanjšati za približno 40 %. Rezultati so bili potrjeni tudi eksperimentalno, pri čemer je razlika med eksperimentalnimi in teoretičnimi vrednostmi le 8 %. V primerjavi s tradicionalnimi PSO-algoritmi, FPSO kaže zanesljivejšo konvergenco pri večparametričnih problemih
Minor children with experience in institutional care and support for children evacuated from Ukrainian institutions for children without parental
No full textV teoretičnem delu magistrske naloge sem preučevala razloge za institucionalizacijo otrok ter vplive, ki jih lahko ima takšna oblika varstva na otrokovo življenje in dobrobit. Nadalje sem se osredotočila na sistem zaščite otrok, pri čemer sem posebno pozornost namenila načelu največje koristi otroka ter pravici do družinskega življenja. V tem okviru sem analizirala tudi vlogo skupnosti in socialnega dela pri ohranjanju duševnega zdravja otrok, s poudarkom na pomenu zagotavljanja pomoči otrokom, ki se soočajo z duševnimi stiskami. S tem širokim teoretičnim okvirjem sem želela prispevati k boljšemu razumevanju potreb in pravic otrok, ki so bili evakuirani iz ukrajinske ustanove za otroke brez starševske oskrbe in so bili izpostavljeni travmatičnim dogodkom, kot so izguba družinskega okolja, institucionalno varstvo ter preselitve zaradi vojne. Te izkušnje lahko povzročijo globoko čustveno stisko, ki negativno vpliva na otrokovo duševno zdravje in celostni razvoj, saj ob tem izgubi občutek varnosti, predvidljivosti in čustvene opore – ključnih temeljev za njegovo dobrobit. Zato ti otroci potrebujejo celovito podporo in pomoč, ki jima omogočata postopno vzpostavitev občutka zaupanja, sprejetosti in pripadnosti. Empirični del temelji na odgovorih in izkušnjah prostovoljcev ter strokovnih delavcev, ki so otrokom nudili podporo. Ugotovitve raziskave poudarjajo, da je za uspešno prilagajanje otrok na novo okolje potreben celostni pristop, ki vključuje tako neformalne kot formalne vire pomoči. Prav tako izpostavljajo potrebo po dodatni podpori strokovnih delavcev in prostovoljcev, mentorstvu, kulturnem zagovorništvu ter medinstitucionalnem sodelovanju.In the theoretical part of my master\u27s thesis, I explored the reasons for the institutionalization of children and the impacts that such forms of care can have on a child\u27s life and well-being. I further focused on the child protection system, with particular attention to the principle of the best interests of the child and the right to family life. In this context, I also analyzed the role of the community and social work in maintaining children\u27s mental health, with an emphasis on the importance of providing support to children facing mental distress. With this broad theoretical framework, I aimed to contribute to a better understanding of the needs and rights of children who were evacuated from a Ukrainian institution for children without parental care and who were exposed to traumatic events such as the loss of family surroundings, institutional care, and displacements due to war. These experiences can cause deep emotional distress that negatively affects the child\u27s mental health and overall development, as they lose the sense of security, predictability, and emotional support—key foundations for their well-being. Therefore, these children need comprehensive support and assistance, which enables the gradual establishment of trust, acceptance, and belonging. The empirical part is based on the responses and experiences of volunteers and professionals who provided support to the children. The findings of the research emphasize that a holistic approach, which includes both informal and formal sources of help, is necessary for the successful adaptation of children to their new environment. They also highlight the need for additional support from professionals and volunteers, mentoring, cultural advocacy, and inter-institutional cooperation
Sestava talne mikrobne združbe in emisije didušikovega oksida v odvisnosti od obdelave tal in gnojenja
No full textReduced tillage intensity is known to increase soil organic carbon (SOC) in the topsoil, but can also lead to increased microbially derived nitrous oxide (N2O) emissions. In this study, we evaluated the effects of two tillage systems [no-till (NT) vs. conventional plough tillage (CT)] in combination with different fertilisation treatments [mineral (MIN), compost (ORG), and unfertilised control (CON)] on soil physical, chemical and biological properties, as well as N2O emissions, after more than two decades. First soil sampling was conducted down to 60 cm, followed by seasonal gas and topsoil (0–10 cm) sampling. In the top 10 cm, higher SOC content was observed in NT than CT, while fertilization affected SOC down to 20 cm, with higher values in ORG fertilization than the other treatments. This pattern correlated with the gradient of microbial biomass and N-functional gene abundances (qPCR). Ratio between the two N2O-reducing communities (nosZI/nosZII) increased significantly with soil depth and was higher in NT than CT, indicating niche differentiation caused by gradients in environmental conditions. The highest seasonal cumulative N2O emissions were in MIN fertilization, followed by ORG and CON, coinciding with AOB/16S ratio as one of the main explanatory variables of multiple regression. A higher genetic potential for N2O emissions was observed under NT than CT, as indicated by an increased (nirK+nirS)/(nosZI+nosZII) ratio, although this potential was not realized in the form of increased emissions. Lower than expected cumulative emissions in NT-ORG were explained by an increased N2O sink potential (PDA), which positively correlated with proportion of nosZII in the metagenome (WGS). Our results suggest combining organic fertilisation with NT as a promising approach for mitigating N2O emissions; however, addressing the yield gap is necessary before incorporating those practices into recommendations for farmers.Znano je, da lahko z manjšo intenzivnostjo obdelave tal povečamo vsebnost organskega ogljika (SOC) v zgornjem sloju tal, kar pa lahko hkrati vodi do večjih emisij didušikovega oksida (N2O) mikrobiološkega izvora. V naši študiji smo po več kot dveh desetletjih analizirali vpliv dveh različnih načinov obdelave tal [brez obdelave tal (NT) v primerjavi s konvencionalno obdelavo tal s plugom (CT)] v kombinaciji z različnimi načini gnojenja [mineralnim gnojenjem (MIN), kompostom (ORG) in negnojeno kontrolo (CON)] na fizikalne, kemične in biološke lastnosti tal ter emisije N2O. Prvo vzorčenje tal smo izvedli do globine 60 cm, nato pa smo sezonsko vzorčili pline in zgornji sloj tal (0–10cm). V zgornjih 0–10 cm tal smo ugotovili večjo vsebnost SOC v NT kot v CT, medtem ko je gnojenje vplivalo na SOC do globine 20 cm z večjimi vsebnostmi pri gnojenju ORG kot pri ostalih. Ta vzorec se je ujemal z gradientom mikrobne biomase in številčnosti N-funkcionalnih genov (qPCR). Razmerje med dvema N2O-reducirajočima združbama (nosZI/nosZII) se je z globino tal znatno povečalo in je bilo večje v NT kot v CT, kar kaže na diferenciacijo niš povzročeno z gradienti okoljskih pogojev. Največje sezonske kumulativne emisije N2O smo ugotovili pri gnojenju MIN, sledila sta ORG in CON, kar sovpada z razmerjem AOB/16S, ki se je pokazalo kot ena glavnih pojasnjevalnih spremenljivk multiple regresije. Večji genetski potencial za emisije N2O, izražen kot večje razmerje (nirK+nirS)/(nosZI+nosZII), smo ugotovili pri NT kot pri CT, vendar se ni odrazil v večjih emisijah. Manjše kumulativne emisije od pričakovanih v NT-ORG smo pojasnili s povečanim potencialom ponora N2O (PDA), ki je pozitivno koreliral z deležem nosZII v metagenomu (WGS). Naši rezultati kažejo, da je organsko gnojenje v kombinaciji z NT obetavna kombinacija za zmanjševanje emisij N2O, vendar je pred vključitvijo teh praks v priporočila za kmete potrebno preučiti tudi njun vpliv na pridelek
Development and validation of a model for the digital transformation of higher education institutions
No full textDigitalna preobrazba visokošolskih institucij predstavlja kompleksen in večrazsežen proces, ki presega zgolj uvajanje novih tehnologij ter zahteva sistemske spremembe na ravni strategije, vodenja, organizacije, procesov in kulture. Kljub številnim obstoječim modelom digitalne preobrazbe ti večinoma niso prilagojeni specifičnostim javnih visokošolskih institucij. Namen magistrskega dela je razviti in empirično preveriti celovit model digitalne preobrazbe visokošolskih institucij, ki upošteva njihove organizacijske, upravljavske in institucionalne značilnosti.
Raziskava temelji na kombinaciji kvalitativnih in kvantitativnih metod. V teoretičnem delu je bil izveden sistematičen pregled literature in obstoječih modelov digitalne preobrazbe, na podlagi katerega je bil oblikovan lasten model. Empirični del vključuje primerjalno analizo digitalnih strategij štirih evropskih univerz ter polstrukturirane intervjuje s predstavniki njihovih vodstev. Podatki so bili analizirani s pomočjo kodne knjige in korelacijske analize.
Rezultati raziskave potrjujejo, da imata jasna digitalna strategija in aktivna vloga vodstva ključen vpliv na stopnjo digitalne preobrazbe visokošolskih institucij, pomembno vlogo pa imajo tudi organizacijska kultura, kadrovski vidiki in sistemi upravljanja. Raziskava ne potrjuje neposredne povezanosti med stopnjo digitalne preobrazbe države in visokošolskih institucij.
Magistrsko delo kot prispevek znanosti ponuja teoretično utemeljen in empirično preverjen model digitalne preobrazbe visokošolskih institucij, ki je hkrati praktično uporaben kot analitični in razvojni okvir za strateško vodenje digitalne preobrazbe v visokošolskih institucijah ter hkrati podlaga za nadaljnje raziskave in izboljšave prakse.The digital transformation of higher education institutions is a complex and multidimensional process that goes beyond the mere introduction of new technologies and requires systemic changes at the level of strategy, management, organization, processes, and culture. Despite the numerous existing models of digital transformation, most of them are not adapted to the specificities of public higher education institutions. The purpose of this master\u27s thesis is to develop and empirically test a comprehensive model of digital transformation of higher education institutions that considers their organizational, managerial, and institutional characteristics.
The research is based on a combination of qualitative and quantitative methods. In the theoretical part, a systematic review of the literature and existing models of digital transformation was carried out, based on which a model was developed. The empirical part includes a comparative analysis of the digital strategies of four European universities and semi-structured interviews with representatives of their management. The data were analysed using a code book and correlation analysis.
The results of the study confirm that a clear digital strategy and an active role of management have a key impact on the level of digital transformation of higher education institutions, while organizational culture, human resources aspects, and management systems also play an important role. The research does not confirm a direct link between the level of digital transformation of a country and higher education institutions.
As a contribution to science, the master\u27s thesis offers a theoretically grounded and empirically tested model of digital transformation of higher education institutions, which is both practically useful as an analytical and developmental framework for the strategic management of digital transformation in higher education institutions and, at the same time, a basis for further research and improvements in practice
Small-scale green roofs with native plant species installed on bus stop shelters
No full textThe University Botanic gardens Ljubljana has been planting vegetation on bus stop shelters in the capital city (Ljubljana) of Slovenia since 2020. The aim of the project is to create a green network across the city, contributing to the conservation of plant biodiversity and providing food resources for pollinators throughout the entire growing season. The plantings were designed exclusively with native plant species, naturally occurring in the territory of Slovenia, flowering from early spring to late autumn. The selected species are also horticulturally attractive, forming small extensive green roof gardens that mimic karst rock ledges, where plants are adapted to drought, shallow soils, and strong sunlight exposure. In 2024 and 2025, monitoring was carried out on eight selected shelters, focusing on plant presence, changes in vegetation cover, and the occurrence of spontaneously sown species and invasive species. The results show that, even after five years without additional maintenance, all plantings are thriving and remain horticulturally attractive. A variety of species flower from early spring to early summer. During drought periods, flowering intensity decreases somewhat but does not ceasein autumn, the shelters green up again with autumn-flowering species. The project has been very well received by the public and is now firmly established in the city. Every year, between 10 and 20 new shelters are planted. By the end of 2025, a total of 75 bus shelters had been greened in all main directions from the city center towards the outskirts
S-packing chromatic critical graphs
No full textFor a non-decreasing sequence of positive integers , the -packing chromatic number of a graph is denoted by . In this paper, -critical graphs are introduced as the graphs such that for each proper subgraph of . Several families of -critical graphs are constructed, and - and -colorable -critical graphs are presented for all packing sequences , while -colorable -critical graphs are found for most of . Cycles which are -critical are characterized under different conditions. It is proved that for any graph and any edge , the inequality holds. Moreover, in several important cases, this bound can be improved to . The sharpness of the bounds is also discussed. Along the way an earlier result on -vertex-critical graphs is supplemented