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1.
Optimization-based downscaling of satellite-derived isotropic broadband albedo to high resolution
Niko Lukač, Domen Mongus, Marko Bizjak, 2025, izvirni znanstveni članek

Opis: In this paper, a novel method for estimating high-resolution isotropic broadband albedo is proposed, by downscaling satellite-derived albedo using an optimization approach. At first, broadband albedo is calculated from the lower-resolution multispectral satellite image using standard narrow-to-broadband (NTB) conversion, where the surfaces are considered Lambertian with isotropic reflectance. The high-resolution true orthophoto for the same location is segmented with the deep learning-based Segment Anything Model (SAM), and the resulting segments are refined with a classified digital surface model (cDSM) to exclude small transient objects. Afterwards, the remaining segments are grouped using K-means clustering, by considering orthophoto-visible (VIS) and near-infrared (NIR) bands. These segments present surfaces with similar materials and underlying reflectance properties. Next, the Differential Evolution (DE) optimization algorithm is applied to approximate albedo values to these segments so that their spatial aggregate matches the coarse-resolution satellite albedo, by proposing two novel objective functions. Extensive experiments considering different DE parameters over an 0.75 km2 large urban area in Maribor, Slovenia, have been carried out, where Sentinel-2 Level-2A NTB-derived albedo was downscaled to 1 m spatial resolution. Looking at the performed spatiospectral analysis, the proposed method achieved absolute differences of 0.09 per VIS band and below 0.18 per NIR band, in comparison to lower-resolution NTB-derived albedo. Moreover, the proposed method achieved a root mean square error (RMSE) of 0.0179 and a mean absolute percentage error (MAPE) of 4.0299% against ground truth broadband albedo annotations of characteristic materials in the given urban area. The proposed method outperformed the Enhanced Super-Resolution Generative Adversarial Networks (ESRGANs), which achieved an RMSE of 0.0285 and an MAPE of 9.2778%, and the Blind Super-Resolution Generative Adversarial Network (BSRGAN), which achieved an RMSE of 0.0341 and an MAPE of 12.3104%.
Ključne besede: isotropic broadband albedo, high-resolution albedo, Sentinel-2 albedo, true orthophoto, anything model, differential evolution
Objavljeno v DKUM: 23.04.2025; Ogledov: 0; Prenosov: 0
.pdf Celotno besedilo (20,47 MB)

2.
Commercial SARS-CoV-2 targeted, protease inhibitor focused and protein–protein interaction inhibitor focused molecular libraries for virtual screening and drug design
Sebastjan Kralj, Marko Jukič, Urban Bren, 2022, pregledni znanstveni članek

Opis: Since December 2019, the new SARS-CoV-2-related COVID-19 disease has caused a global pandemic and shut down the public life worldwide. Several proteins have emerged as potential therapeutic targets for drug development, and we sought out to review the commercially available and marketed SARS-CoV-2-targeted libraries ready for high-throughput virtual screening (HTVS). We evaluated the SARS-CoV-2-targeted, protease-inhibitor-focused and protein–protein-interactioninhibitor-focused libraries to gain a better understanding of how these libraries were designed. The most common were ligand- and structure-based approaches, along with various filtering steps, using molecular descriptors. Often, these methods were combined to obtain the final library. We recognized the abundance of targeted libraries offered and complimented by the inclusion of analytical data; however, serious concerns had to be raised. Namely, vendors lack the information on the library design and the references to the primary literature. Few references to active compounds were also provided when using the ligand-based design and usually only protein classes or a general panel of targets were listed, along with a general reference to the methods, such as molecular docking for the structure-based design. No receptor data, docking protocols or even references to the applied molecular docking software (or other HTVS software), and no pharmacophore or filter design details were given. No detailed functional group or chemical space analyses were reported, and no specific orientation of the libraries toward the design of covalent or noncovalent inhibitors could be observed. All libraries contained pan-assay interference compounds (PAINS), rapid elimination of swill compounds (REOS) and aggregators, as well as focused on the drug-like model, with the majority of compounds possessing their molecular mass around 500 g/mol. These facts do not bode well for the use of the reviewed libraries in drug design and lend themselves to commercial drug companies to focus on and improve.
Ključne besede: targeted libraries, focused libraries, computer-aided drug design, virtual screening, in silico drug design, high-throughput virtual screening
Objavljeno v DKUM: 09.04.2025; Ogledov: 0; Prenosov: 1
.pdf Celotno besedilo (6,53 MB)
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3.
Mechanism elucidation of high-pressure generation in cellular metal at high-velocity impact
Masatoshi 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: 2
.pdf Celotno besedilo (3,90 MB)
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4.
A review of analytical techniques for the determination of e-liquid and electronic cigarette aerosol composition
Matjaž Rantaša, David Majer, Matjaž Finšgar, 2025, pregledni znanstveni članek

Opis: Since the introduction of electronic cigarettes (ECs) to the global market, the composition of e-liquids has been a controversial topic. While some consider ECs to be an effective tool for quitting smoking, their primary criticism lies in the uncertain and varied composition of e-liquids. Manufacturers create the desired formulations by mixing different ratios of humectants, flavorings, nicotine, cannabinoids, and cooling agents. However, the health effects of inhaling these compounds are still not well understood. Regular analytical control of e-liquids and aerosols is crucial to gain valuable insights into e-liquid composition, generating new compounds during aerosolization, and the potential impact on human health. This work presents an overview of the analytical techniques used for the qualitative and quantitative determination of e-liquid and aerosol compounds, including a description of the methods used for aerosol collection. Gas and liquid chromatography are the most used analytical techniques for compound determination, followed by nuclear magnetic resonance spectroscopy. Additionally, inductively coupled plasma-mass spectrometry and inductively coupled plasma-optical emission spectroscopy are the most frequently used analytical techniques for elemental determination in e-liquids and their aerosols.
Ključne besede: electronic cigarettes, e-liquids, aerosol, gas chromatography, high-performance liquid chromatography, inductively coupled plasma mass spectrometry
Objavljeno v DKUM: 21.03.2025; Ogledov: 0; Prenosov: 2
.pdf Celotno besedilo (2,11 MB)

5.
Cast microstructure of a complex concentrated noble alloy ▫$Ag_{20}Pd_{20}Pt_{20}Cu_{20}Ni_{20}▫$
Lidija Simić, Rebeka Rudolf, Peter Majerič, Ivan Anžel, 2022, izvirni znanstveni članek

Opis: A complex concentrated noble alloy (CCNA) of equiatomic composition (Ag20Pd20Pt20Cu20Ni20 –20 at. %) was studied as a potential high—performance material. The equiatomic composition was used so that this alloy could be classified in the subgroup of high—entropy alloys (HEA). The alloy was prepared by induction melting at atmospheric pressure, using high purity elements. The degree of metastability of the cast state was estimated on the basis of changes in the microstructure during annealing at high temperatures in a protective atmosphere of argon. Characterisation of the metallographically prepared samples was performed using a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS), differential scanning calorimetry (DSC), and X–ray diffraction (XRD). Observation shows that the microstructure of the CCNA is in a very metastable state and multiphase, consisting of a continuous base of dendritic solidification—a matrix with an interdendritic region without other microstructural components and complex spheres. A model of the probable flow of metastable solidification of the studied alloy was proposed, based on the separation of L—melts into L1 (rich in Ni) and L2 (rich in Ag). The phenomenon of liquid phase separation in the considered CCNA is based on the monotectic reaction in the Ag−Ni system.
Ključne besede: complex concentrated noble alloy, high—entropy alloy, metastability
Objavljeno v DKUM: 20.03.2025; Ogledov: 0; Prenosov: 4
.pdf Celotno besedilo (4,00 MB)
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7.
Crash testing program in hyper-electrical vehicles : magistrsko delo
Filip Mehmetović, 2025, magistrsko delo

Opis: The main goal of the master's thesis is to present system solutions (HW or SW) in electric hyper-vehicles for the purpose of preparing crash tests on such vehicles. The aim is to showcase the system as a whole and to identify deviations and changes that would need to be made for a high-quality test preparation.
Ključne besede: Crash Simulation, High-Voltage Safety, Pyrofuse Activation, Vehicle Integration, Diagnostic Systems
Objavljeno v DKUM: 27.02.2025; Ogledov: 0; Prenosov: 12
.pdf Celotno besedilo (5,77 MB)

8.
High resolution short response time fiber-optic temperature sensor
Nermin Sinanović, Simon Pevec, Matej Njegovec, Vedran Budinski, Denis Đonlagić, 2025, izvirni znanstveni članek

Opis: This article presents an all-silica microwire optical sensor designed for both fast response time and high-resolution temperature detection. The sensor consists of a thin optical microwire created at the tip of an optical fiber, configured as a temperature sensitive Fabry–Perot interferometer (FPI). For the purposes of achieving rapid response times, the sensing section of the sensor has a diameter of 11 µm. Experimental bench tests were set up to evaluate the sensor’s static and dynamic performance. The results indicate a sensor system resolution of about 5 mK and demonstrate a bandwidth of 38 Hz that corresponds to a response time of 4 ms in still air. The sensor’s functionality is shown through a basic periodic gas compression method detecting small temperature fluctuations. In addition, the sensor was demonstrated for operation up to 600 ◦C.
Ključne besede: Fabry-Perot, high-resolution temperature sensor, micromachining, microwire optic sensor, optical fibers, short response time
Objavljeno v DKUM: 12.02.2025; Ogledov: 0; Prenosov: 6
.pdf Celotno besedilo (8,03 MB)

9.
The influence of the ratio of circumference to cross-sectional area of tensile bars on the fatigue life of additive manufactured AISI 316L steel
Luka Ferlič, Filip Jerenec, Mario Šercer, Igor Drstvenšek, Nenad Gubeljak, 2024, izvirni znanstveni članek

Opis: The static and dynamic loading capacities of components depend on the stress level to which the material is exposed. The fatigue behavior of materials manufactured using additive technology is accompanied by a pronounced scatter between the number of cycles at the same stress level, which is significantly greater than the scatter from a material with the same chemical composition, e.g., AISI 316L, but produced by rolling or forging. An important reason lies in the fact that fatigue cracks are initiated almost always below the material surface of the loaded specimen. Thus, in the article, assuming that a crack will always initiate below the surface, we analyzed the fatigue behavior of specimens with the same bearing cross section but with a different number of bearing rods. With a larger number of rods, the circumference around the supporting part of the rods was 1.73 times larger. Thus, experimental fatigue of specimens with different sizes showed that the dynamic loading capacity of components with a smaller number of bars is significantly greater and can be monitored by individual stress levels. Although there are no significant differences in loading capacity under static and low-cycle loading of materials manufactured with additive technologies, in high-cycle fatigue it has been shown that the ratio between the circumference and the loading cross section of tensile-loaded rods plays an important role in the lifetime. This finding is important for setting a strategy for manufacturing components with additive technologies. It shows that a better dynamic loading capacity can be obtained with a larger loading cross section.
Ključne besede: AISI 316L stainless steel, additive manufacturing, FEM, high-cycle fatigue, fractography analysis
Objavljeno v DKUM: 25.11.2024; Ogledov: 0; Prenosov: 15
.pdf Celotno besedilo (33,45 MB)
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10.
Behaviour of cellular metamaterials under impact loading conditions : doctoral disertation
Yunus Emre Yilmaz, 2024, doktorska disertacija

Opis: This doctoral thesis investigates cell-size-graded metallic and non-metallic Triply Periodic Minimal Surface (TPMS) structures' behavior under varying loading rates. Using experimental tests, analytical calculations, and advanced computer simulations, the research explores the interplay between material properties, cell size grading, and deformation mechanisms under different strain rates. The study focuses on enhancing the Direct Impact Hopkinson Bar (DIHB) setup for accurate force and displacement measurements and pioneering a method for quantifying inertial forces, critical at high strain rates. Key findings show that cell-size grading significantly affects deformation patterns, with initial deformation occurring in regions with smaller and lower stiffness cells across different loading rates and TPMS geometries. The research also highlights topology's influence on mechanical response, with photopolymer-based diamond structures showing superior energy absorption and gas-atomized steel structures favoring gyroid configurations. This underscores the importance of considering both topology and base material selection during TPMS design. The study demonstrates the increasing prominence of inertial forces as deformation rates rise, impacting structural response and failure likelihood in TPMS structures. These insights inform the design of optimized cellular metamaterials for high-performance applications requiring superior energy absorption and structural integrity under high loading rates. The research advances material characterization techniques and computational modelling capabilities, contributing to the development of next-generation cellular metamaterials for broader engineering applications.
Ključne besede: Triply Periodic Minimal Surfaces, TPMS, Cell-size-grading, Impact, High-strainrate, Digital Image Correlation
Objavljeno v DKUM: 17.10.2024; Ogledov: 0; Prenosov: 31
.pdf Celotno besedilo (46,48 MB)

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