1. 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: 2
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2. Nanochemistry and Materials : a Laboratory ManualJanja Stergar, Irena Ban, 2022, delovni zvezek za višje in visoke šole Opis: The publication contains instructions for laboratory work in the subject Nanochemistry and Materials. Students are introduced to the experimental principles of nanochemistry in the laboratory. They learn about various synthesis and characterization methods, in conjunction with magnetic nanoparticles useful in biomedical and engineering applications. They learn about the safety of nanoparticles and their effects, impact on technology, and contribution to improving life on many levels when used properly. The instructions are written in English as they are intended for foreign students who choose the mentioned subject.
Ključne besede: magnetic nanoparticles, coprecipitation, microemulsion technique, X-Ray powder diffraction, dynamic light scattering
Objavljeno v DKUM: 29.08.2022; Ogledov: 686; Prenosov: 95
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3. Ammoniumbis(hydroxylammonium) pentafluoridooxidovanadate(IV) : synthesis and characterisation of a new fluorovanadateBrina Dojer, Matjaž Kristl, Zvonko Jagličić, Mihael Drofenik, Anton Meden, 2008, izvirni znanstveni članek Opis: Turquoise crystals of a new hydroxylammonium compound with the formula $NH_4(NH_3OH)_2[VOF_5]$ have been synthesized by the reaction of solid $NH_3OHF$ and the aqueous solution of vanadium in HF. The compound crystallizes monoclinic, $P2_1/n$, with cell parameters: a = 10.5658(2) Å, b = 6.6143(1) Å, c = 11.6618(2) Å, β = 96.282(1). Magnetic susceptibility was measured using a SQUID device over a temperature range 2–300 K at magnetic field $10^3 Oe$ giving the result $µ_{eff}$ = 1.65 BM. The thermal decomposition was studied by TG and DSC analysis. $NH_4(NH_3OH)_2[OF_5V]$ decomposes above 354 K in three steps, obtaining $NH_4VOF_3$ after the first step and $V_2O_5$ as the final residue.
Ključne besede: hydroxylammonium fluorovanadates, x-ray powder diffraction, x-ray structure determination, thermal analysis
Objavljeno v DKUM: 17.08.2017; Ogledov: 1850; Prenosov: 112
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5. Fatigue properties of sintered DIN SINT-D30 powder metal before and after heat treatmentMarko Šori, Borivoj Šuštaršič, Srečko Glodež, 2014, izvirni znanstveni članek Opis: The main focus of this study was to determine how heat treatment affects the dynamic properties of sintered steel. All the specimens were made of the DIN SINT-D30 metal powder, but only half of them were additionally heat treated. Flat specimens were cold pressed and sintered. The second set was additionally heat treated to increase the strength. After the static mechanical properties were determined, the fatigue strength was investigated in a pulsating machine with a load ratio of R = 0. Wöhler curves were plotted and the parameters for determining the fatigue life (of' and b) were calculated.
Ključne besede: powder metallurgy, fatigue, S-N curve
Objavljeno v DKUM: 16.03.2017; Ogledov: 1400; Prenosov: 126
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6. Water sorption characteristics of a new type of gelatine powder, produced by a new high-pressure micronisation processChristian Reibe, Željko Knez, 2010, izvirni znanstveni članek Opis: A new high-pressure micronisation process for Gelatine has been developed. By applying this process to gelatine, a new type of Gelatine was produced: Dry and pure Gelatine powder of high molecular mass. This powder was investigated,regarding its sorption behaviour and compared to its feedstock material. The feedstock Gelatine was of type B 200 Bloom, 6 mesh, having a molecular mass of 150,000 g $mol^{-1}$. The produced Gelatine powder's molecular mass was around 130,000 g $mol^{-1}$, while its mean particle size was 300 μm. Their sorption isotherms were investigated at 30 °C, 40 °C and 60 °C and water activities in the range from 0.055 to 0.836. At given water activities the Equilibrium Moisture Contents (EMC) decreases with increasing temperature.The measured sorption isotherms were fit with the Brunauer- Emmet-Teller (BET)- model and the Guggenheim- Anderson- deBoer (GAB)- model. Both models described the adsorption behaviour well in their range of validity, while only the GAB-model was adequate for describing the desorption behaviour. Hysteresis effect occurred in each adsorption-desorption pair. The isosteric heat of sorption of both substances was determined for adsorption, desorption respectively. Slight differences in the sorption behaviour occurred due to processing, while quality of the gelatine was not affected.
Ključne besede: $CO_2$ spray drying, gelatine powder, sorption isotherms, isosteric heat of sorption, Guggenheim-Anderson-deBoer model, Brunauer-Emmet-Teller model
Objavljeno v DKUM: 10.07.2015; Ogledov: 1887; Prenosov: 84
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7. Dynamic property of aluminium foamSeiichi Irie, Toshihiko Okano, Shigeru Tanaka, Matej Vesenjak, Zoran Ren, Kazuyuki Hokamoto, Shigeru Itoh, 2010, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: aluminium foam, powder gun, high strain rate
Objavljeno v DKUM: 10.07.2015; Ogledov: 1739; Prenosov: 50
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8. Particles formation and particle design using supercritical fluidsŽeljko Knez, Eckhard Weidner, 2003, pregledni znanstveni članek Opis: Major recent advances. Particle formation and design of solid particles and powdery composites with unique properties is at the moment a major developmentof supercritical fluids (synonymsČ dense gasses, dense fluids, highpressure) applications. This review will focus on recent advances and on fundamentals of these processes and their applications.
Ključne besede: chemical processing, high pressure technology, micronization, supercritical fluids, micro-particles, nano-particles, powder generation, crystallization, particles from gas saturated solutions
Objavljeno v DKUM: 01.06.2012; Ogledov: 3777; Prenosov: 112
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9. Multifunctional composites by high-pressure spray processesEckhard Weidner, Marcus Petermann, Željko Knez, 2003, pregledni znanstveni članek Opis: A series of spraying processes designed to generate powders and composites using supercritical fluids have been proposed in the past 15 years. In this review, thermo- and fluid-dynamic aspects and engineering principles are discussed and advantages of such technologies are demonstrated. These new techniques display convincing advantages, producing competitive high-quality products with tailor-made properties. Initial industrial applications have been achieved in the production of food products and fine-chemicals.
Ključne besede: chemical processing, high pressure technology, micronization, supercritical fluids, particles, powder generation, thermodynamics, fluid dynamics, PGSS
Objavljeno v DKUM: 01.06.2012; Ogledov: 2658; Prenosov: 107
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10. Hydroxylammonium fluorogermanatesIrena Ban, Matjaž Kristl, Mihael Drofenik, Arkadije Popović, 2004, izvirni znanstveni članek Opis: A new hydroxylammonium compound (NH3OH)2GeF6, has been synthesized by the addition of solid NH3OHF to a solution of GeO2 dissolved in 20% HF. The compound was characterized by chemical analysis and X-ray powder diffraction, the thermal decomposition was studied by thermal analysis and mass spectrometry. (NH3OH)2GeF6 crystallizes monoclinic. Two endothermic and two exothermic peaks have been observed on the DSC curve, the decomposition product at 500 °C is GeO2.
Ključne besede: inorganic chemistry, synthesis, characterisation, hydroxylammonium fluorogermanates, x-ray powder diffraction, mass spectroscopy, thermal analysis
Objavljeno v DKUM: 01.06.2012; Ogledov: 3353; Prenosov: 115
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