1. Enhancing strength and ▫$CO_2$▫ uptake in lignite-based fly ash geopolymer mortar through supercritical carbonationTinkara Marija Podnar, Željko Knez, Gregor Kravanja, 2025, izvirni znanstveni članek Opis: This study demonstrates the potential of supercritical CO₂ curing to enhance the performance and sustainability of lignite-based fly ash geopolymer mortar offering a promising approach to reducing CO₂ emissions in the construction industry while improving material properties. The research comprehensively compared conventional curing (GEO-REF) with supercritical CO₂ curing (GEO-CO₂), revealing that GEO-CO₂ samples exhibited higher compressive and flexural strengths, achieving peak performance almost immediately after curing. Supercritical CO₂ exposure resulted in enhanced carbonation, with a depth of up to 7.6 mm and a carbonation rate of up to 67 %. XRD confirmed phase changes due to CO₂ curing, with GEO-CO₂ showing additional calcium carbonate-calcite, calcium carbonate-aragonite, and calcium silicate hydroxide compared to GEO-REF. Nitrogen adsorption/desorption studies indicated larger pore diameters but a reduced BET surface area in GEO-CO₂ samples, suggesting structural changes due to CO₂ exposure. TGA analysis revealed that supercritical CO₂ curing reduced water retention and enhanced carbonation, resulting in increased CaCO₃ content and changes in Ca(OH)₂ levels.
Ključne besede: geopolymer, fly ash, carbonation, CO2 fixation, supercritical CO2, high pressure reactor
Objavljeno v DKUM: 25.07.2025; Ogledov: 0; Prenosov: 3
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2. Experimental testing and numerical bite simulation of complete acrylic dentures in eugnathic and progenic occlusal relationshipsMartin Pavlin, Robert Ćelić, Nenad Gubeljak, Jožef Predan, 2025, izvirni znanstveni članek Opis: Complete dentures are exposed to complex masticatory forces that may lead to material fatigue and eventual structural failure. Occlusal relationships, such as eugnathic and progenic, influence the distribution of these forces significantly. Understanding their biomechanical impact is essential for improving denture design and longevity. The aim of this study was to evaluate the mechanical behaviour of complete dentures under bite loads in eugnathic and progenic occlusal relationships, using both experimental testing and numerical simulations. The focus was placed on identifying the conditions that lead to initial damage and the patterns of stress distribution. The material properties of the denture base and artificial teeth were determined through experimental tensile and compressive testing on cylindrical PMMA specimens. The denture geometry was acquired via 3D tomography based on impressions of an edentulous patient. Experimental testing of the denture bite was conducted to determine the force thresholds at which the initial cracks occur. Numerical simulations were carried out using finite element analysis at bite loads of 100 N and 200 N in both occlusal types, incorporating the obtained material parameters. The experimental results showed that the first signs of denture damage occurred at 6400 N in eugnathic occlusion and 7010 N in progenic occlusion. The numerical simulations confirmed that, during occlusion, the pressure is redistributed across multiple contact points, with a broader distribution reducing the localised stress. This redistribution was more efficient in eugnathic occlusion, which reduced the risk of longitudinal cracking in acrylic teeth. In contrast, progenic occlusion showed higher susceptibility to fractures within the acrylic denture base, particularly between adjacent teeth. Both the experimental and numerical approaches demonstrated that occlusal relationships affect the mechanical resilience of complete dentures directly. The findings highlight that eugnathic occlusion offers biomechanical advantages in stress distribution, potentially reducing the risk of fracture. Incorporating occlusal analysis into denture design protocols can enhance clinical outcomes and improve prosthetic longevity.
Ključne besede: bite force, finite element method, dental biomechanics, numerical simulations, complete acrylic dentures, occlusal force distribution, occlusal pressure distribution
Objavljeno v DKUM: 11.06.2025; Ogledov: 0; Prenosov: 8
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3. Mechanism elucidation of high-pressure generation in cellular metal at high-velocity impactMasatoshi Nishi, Shigeru Tanaka, Akihisa Mori, Matej Vesenjak, Zoran Ren, Kazuyuki Hokamoto, 2022, izvirni znanstveni članek Opis: Cellular metals exhibit diverse properties, depending on their geometries and base materials. This study investigated the mechanism of high-pressure generation during the high-velocity
impact of unidirectional cellular (UniPore) materials. Cubic UniPore copper samples were mounted
on a projectile and subjected to impact loading using a powder gun to induce direct impact of samples.
The specimens exhibited a unique phenomenon of high-pressure generation near the pores during
compression. We elucidate the mechanism of the high-pressure phenomenon and discuss the pore
geometries that contribute to the generation of high pressures.
Ključne besede: cellular metal, high-pressure, high-velocity impact, computational simulation, metal jet
Objavljeno v DKUM: 24.03.2025; Ogledov: 0; Prenosov: 6
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4. Strain rate-dependent compressive properties of bulk cylindrical 3D-printed samples from 316L stainless steelMichaela Neuhauserova, Petr Koudelka, Tomáš Fíla, Jan Falta, Václav Rada, Jan Sleichrt, Petr Zlámal, Anja Mauko, Ondřej Jiroušek, 2022, izvirni znanstveni članek Opis: The main aim of the study was to analyse the strain rate sensitivity of the compressive
deformation response in bulk 3D-printed samples from 316L stainless steel according to the printing
orientation. The laser powder bed fusion (LPBF) method of metal additive manufacturing was
utilised for the production of the samples with three different printing orientations: 0◦
, 45◦
, and 90◦
.
The specimens were experimentally investigated during uni-axial quasi-static and dynamic loading.
A split Hopkinson pressure bar (SHPB) apparatus was used for the dynamic experiments. The
experiments were observed using a high-resolution (quasi-static loading) or a high-speed visible-light
camera and a high-speed thermographic camera (dynamic loading) to allow for the quantitative and
qualitative analysis of the deformation processes. Digital image correlation (DIC) software was used
for the evaluation of displacement fields. To assess the deformation behaviour of the 3D-printed
bulk samples and strain rate related properties, an analysis of the true stress–true strain diagrams
from quasi-static and dynamic experiments as well as the thermograms captured during the dynamic
loading was performed. The results revealed a strong strain rate effect on the mechanical response of
the investigated material. Furthermore, a dependency of the strain-rate sensitivity on the printing
orientation was identified.
Ključne besede: 3D printing, laser powder bed fusion, 316L stainless steel, printing direction, split Hopkinson pressure bar
Objavljeno v DKUM: 20.03.2025; Ogledov: 0; Prenosov: 10
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5. αP-x,y equilibrium data of the binary systems of 1-Butanol and 2-Butanol with argon at 313.15 K and 333.15 K – measurements and modelingDragana Borjan, Mariusz Nowak, Irena T. Žižović, Željko Knez, Maša Knez Marevci, 2024, izvirni znanstveni članek Ključne besede: high-pressure phase equilibrium Argon, 1-butanol, 2-butanol, Peng-Robinson equation of state, Boston-Mathias alpha function
Objavljeno v DKUM: 19.03.2025; Ogledov: 0; Prenosov: 3
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6. Hemodynamic response to high- and low-load resistance exercise in patients with coronary artery disease : a randomized, crossover clinical trialTim Kambič, Vedran Hadžić, Mitja Lainščak, 2021, izvirni znanstveni članek Opis: Low-load resistance exercise (LL-RE) is recommended as an adjunct therapy to aerobic exercise during cardiac rehabilitation in patients with coronary artery disease. The safety and hemodynamic response to high-load (HL) RE remain unknown. The aim of this study was to evaluate the hemodynamic response during both HL-RE and LL-RE prior to cardiac rehabilitation. Forty-three patients with coronary artery disease and/or percutaneous coronary intervention performed three sets of leg-press exercise using HL-RE (eight repetitions at the intensity of 80% of one repetition maximum (1-RM)) and LL-RE (16 repetitions at the intensity of 40% 1-RM) in a randomized crossover sequence. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and rating of perceived exertion were measured at baseline, after each set of RE and post-exercise. No clinically relevant changes in HR and BP or in patient-reported symptoms were recorded during HL-RE or LL-RE. Compared with baseline, HR and SBP increased during LL-RE (from 66 bpm to 86 bpm, time effect: p < 0.001; from 129 mmHg to 146 mmHg, time effect: p < 0.001) and HL-RE (from 68 bpm to 86 bpm, time effect: p < 0.001; from 130 mmHg to 146 mmHg, time effect: p < 0.001). Compared with HL-RE, the increase in HR was greater after the final set of LL-RE (32% vs. 28%, p = 0.015), without significant differences in SBP and DBP between LL-RE and HL-RE. Rating of perceived exertion was higher after the 1st set of HL-RE compared with LL-RE (median (interquartile range): 6 (5–7) vs. 6 (5–6), p = 0.010). In patients with coronary artery disease, both HL-RE and LL-RE were safe and well-tolerated. Hemodynamic changes were similar and within the physiological response to RE.
Ključne besede: sport, cardiac rehabilitation, resistance training, blood pressure, heart rate
Objavljeno v DKUM: 20.08.2024; Ogledov: 85; Prenosov: 10
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7. Impact of short-term topical steroid therapy on selective laser trabeculoplasty efficacyTomaž Gračner, 2021, izvirni znanstveni članek Opis: Background: To evaluate whether short-term use of topical steroid therapy affected the efficacy of selective laser trabeculoplasty (SLT) for primary open-glaucoma (POAG). Methods: 25 eyes of 25 patients, who used a drop of dexamethasone 0.1% 4 times a day for 7 days as post-laser therapy, formed the Steroid SLT group and 24 eyes of 24 patients, where no topical steroids or nonsteroidal anti-inflammatory agents as post-laser therapy were used, formed the No-steroid SLT group. Success was defined as an intraocular pressure (IOP) lowering exceeding 20% of pretreatment IOP. Results: The mean follow-up time was 21.24 months for the Steroid SLT group and 20.25 months for the No-steroid SLT group (p = 0.990). No significant difference was found between the two groups for mean pretreatment IOP (22.20 mmHg vs. 22.33 mmHg), and for mean IOP reductions during whole follow-up period. At all follow-up visits, the mean IOP reductions were smaller in the Steroid SLT group than in the No-steroid SLT group. At all follow-up visits, the mean percent IOP reduction was smaller in the Steroid SLT group than in the No-steroid SLT group, and such a difference was significant at 12 months (25.4% vs. 29.6%, p = 0.047) and 24 months (25.3% vs. 29.7%, p = 0.024). According to the Kaplan–Meier survival analysis, the 24-month success rate was 84% in the Steroid SLT group and 79.2% in the No-steroid SLT group, with no differences between the groups (p = 0.675). Conclusion: Short-term use of topical steroid therapy had no impact on the efficacy of SLT for POAG.
Ključne besede: selective laser trabeculoplasty, topical steroid therapy, primary open-angle glaucoma, intraocular pressure
Objavljeno v DKUM: 14.08.2024; Ogledov: 122; Prenosov: 10
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8. Telemonitoring of elderly with hypertension and type 2 diabetes at the primary care level : protocol for a multicentric randomized controlled pilot studyMatic Mihevc, Črt Zavrnik, Majda Mori-Lukančič, Tina Virtič, Valentina Prevolnik Rupel, Marija Petek Šter, Zalika Klemenc-Ketiš, Tonka Poplas-Susič, 2022, izvirni znanstveni članek Opis: Introduction: Arterial hypertension (AH) and type 2 diabetes (T2D) represent a significant burden for the public health system, with an exceptionally high prevalence in patients aged ≥65 years. This study aims to test the acceptability, clinical effectiveness, and cost-effectiveness of telemonitoring in elderly patients with AH and T2D at the primary care level.
Methods: A m ulti-centre, prospective, randomized, controlled t rial w ill be conducted. Patients a ged ≥ 65 y ears with AH and T2D will be randomized in a 1:1 proportion to a mHealth intervention or standard care group. Patients in the intervention group will measure their blood pressure (BP) twice weekly and blood glucose (BG) once monthly. The readings will be synchronously transmitted via a mobile application to the telemonitoring platform, where they will be reviewed by a general practitioner who will indicate changes in measurement regimen or carry out a teleconsultation. The primary endpoint will be a change in systolic BP (SBP) and glycated haemoglobin (HbA1c) relative to standard care up to 12 months after inclusion. Secondary endpoints will be a change in other observed clinical variables, quality-of-life indexes, and costs.
Expected results: Telemonitoring will be an acceptable method of care associated with significant reductions in SBP and HbA1c levels and an increase in quality-of-life indexes in the intervention group. However, the cost-effectiveness threshold (incremental cost-effectiveness ratio below €25,000/quality-adjusted life year) might not be reached.
Conclusion: This study will provide new evidence for scaling up telemonitoring network at the primary care level and modifying telemonitoring protocols to achieve the best clinical and cost-effective outcomes.
Ključne besede: mobile health, telemonitoring, blood pressure, blood glucose, HbA1c, aged, primary health care, costs
Objavljeno v DKUM: 27.06.2024; Ogledov: 178; Prenosov: 10
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9. Loss of oxygen atoms on well-oxidized cobalt by heterogeneous surface recombinationDomen Paul, Miran Mozetič, Rok Zaplotnik, Jernej Ekar, Alenka Vesel, Gregor Primc, Denis Đonlagić, 2023, izvirni znanstveni članek Opis: Calorimetry is a commonly used method in plasma characterization, but the accuracy of the method is tied to the accuracy of the recombination coefficient, which in turn depends on a number of surface effects. Surface effects also govern the kinetics in advanced methods such as atomic layer oxidation of inorganic materials and functionalization of organic materials. The flux of the reactive oxygen atoms for the controlled oxidation of such materials depends on the recombination coefficient of materials placed into the reaction chamber, which in turn depends on the surface morphology, temperature, and pressure in the processing chamber. The recombination coefficient of a well-oxidized cobalt surface was studied systematically in a range of temperatures from 300 to 800 K and pressures from 40 to 200 Pa. The coefficient increased monotonously with decreasing pressure and increasing temperature. The lowest value was about 0.05, and the highest was about 0.30. These values were measured for cobalt foils previously oxidized with oxygen plasma at the temperature of 1300 K. The oxidation caused a rich morphology with an average roughness as deduced from atomic force images of 0.9 µm. The results were compared with literature data, and the discrepancy between results reported by different authors was explained by taking into account the peculiarities of their experimental conditions.
Ključne besede: heterogeneous surface recombination, recombination coefficient, cobalt, cobalt oxide, temperature dependence, pressure dependence, plasma, oxygen
Objavljeno v DKUM: 26.03.2024; Ogledov: 228; Prenosov: 20
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10. Cavitation erosion modelling : comparison of different driving pressure approachesLuka Kevorkijan, Marko Pezdevšek, Ignacijo Biluš, Gorazd Hren, 2023, izvirni znanstveni članek Opis: In this paper we compared different driving pressure approaches to calculate the cavitation potential energy from a source, which is transferred to a surface. The first approach used the reference pressure, the second approach used the pressure calculated at each timestep with no averaging, the third approach used the averaged pressure values from all timesteps included in one shedding cycle, and the last approach used pressure values from the steady state simulations results. The results show that for all formulations the averaged pressure values and steady state pressure values give similar results in terms of mean potential power distribution on the hydrofoil surface as in absolute values. The reference pressure approach gave similar results for the derivative and divergence formulation while for the source term the mean potential power distribution on the hydrofoil surface differs and the maximums were near the leading edge. The approach where we used no pressure averaging gave adequate results in terms of mean potential power distribution but differs from other approaches in absolute values which were considerably lower for all potential power formulations.
Ključne besede: cavitation, erosion potentional, driving pressure, numerical simulations
Objavljeno v DKUM: 21.02.2024; Ogledov: 400; Prenosov: 296
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