Leibniz-Institut für Werkstofforientierte Technologien - IWT
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Institut für Werkstofftechnik (IWT)
Stiftung Institut für Werkstofftechnik IWT
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Item type:Publication, Redox Activity and Nano–Bio Interactions Determine the Skin Injury Potential of Co3O4-Based Metal Oxide Nanoparticles toward Zebrafish(American chemical society, 2020-03-19); ; ; ; Redox-active metal oxide nanoparticles show varying oxidizing capacities and injury potentials toward biological systems. Here, two metal oxide libraries including transition-metal-doped Co3O4 and PdO-Co3O4 with strong chemical contacts were design-synthesized and used to investigate their biological injury potential and mechanisms using zebrafish as a model organism. Among different dopants, Cu significantly increased the oxidizing capacity of Co3O4. An increased amount of PdO resulted in higher density of heterojunctions, which also led to higher oxidizing capacity. The oxidizing capacity of these nanoparticles was positively correlated with higher mortality of dechorionated embryos and severe larval skin injury upon exposure. Using transgenic zebrafish Tg(LysC:eGFP), we show in real time that the redox-active nanoparticles induced skin injury and activated the infiltration of immune cells. Such inflammatory response was confirmed by the increased mRNA expression level of Nrf2a, HO-1, IL-1β, and IL-6 genes. Although the exposure to the nanoparticles alone was not lethal, the skin injury did lower the tolerance level against other environmental contaminants. More importantly, after withdrawing from the nanoparticle exposure, larvae with skin injury could recover within 24 h in uncontaminated medium, indicating such injury was transient and recoverable.journal articleBand:14Heft:433 37 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Laseradditive Fertigung von Ti-6Al-4V: Prozessschrittübergreifende Korrelation zwischen Einzelfaktoren und resultierenden Eigenschaften(2025-12-11); ; 99 87 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Beating Thermal Coarsening in Nanoporous Materials via High-Entropy DesignControlling the feature sizes of 3D bicontinuous nanoporous (3DNP) materials is essential for their advanced applications in catalysis, sensing, energy systems, etc., requiring high specific surface area. However, the intrinsic coarsening of nanoporous materials naturally reduces their surface energy leading to the deterioration of physical properties over time, even at ambient temperatures. A novel 3DNP material beating the universal relationship of thermal coarsening is reported via high-entropy alloy (HEA) design. In newly developed TiVNbMoTa 3DNP HEAs, the nanoporous structure is constructed by very fine nanoscale ligaments of a solid-solution phase due to enhanced phase stability by maximizing the configuration entropy and suppressed surface diffusion. The smallest size of 3DNP HEA synthesized at 873 K is about 10 nm, which is one order of magnitude smaller than that of conventional porous materials. More importantly, the yield strength of ligament in 3DNP HEA approaches its theoretical strength of G/2π of the corresponding HEA alloy even after thermal exposure. This finding signifies the key benefit of high-entropy design in nanoporous materials—exceptional stability of size-related physical properties. This high-entropy strategy should thus open new opportunities for developing ultrastable nanomaterials against its environment.journal article137 350 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Use of the Size Effect in Grinding for Work-hardeningThis paper shows the possibility of using the size effect of the specific grinding energy for a targeted surface layer work-hardening of metal parts. The research includes the combination of abrasive material removal and plastic deformation in a single grinding step. Therefore high specific energy values are needed and thermal effects counteracting the work-hardening have to be minimised. This can be achieved by low cutting speeds in combination with low depths of cut. The new approach results in an in-process work-hardening of the surface layer, which was found to lead to higher hardness, a compressive residual stress state, and higher wear resistance.journal articleBand:56Heft:189 76 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Atomization efficiency enhancement in internal-mixing Y-jet nozzles using distinct dispersing media(2025-09-19); ; 50 49 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The impact of metal doping on fumed silica structure and amino acid thermal condensation catalytic properties(Springer, 2021-08-18); ; ; ; Fumed silica nanoparticles (FSN) are one of the most common synthetic forms of silica, but prolonged exposure leads to cell toxicity and apoptosis due to reactive oxygen species (ROS) generation and cell membrane perturbation resulting from hydrogen bonding and electrostatic interactions. Increasing attention is being put on synthesizing FSN material that is safer both for workers involved in large-scale industrial production, and consumers coming in contact with FSN additives. In the present work, we explore the molecular structural differences and efficacy of Al- and Ti-metal-doped FSN which has previously been shown to reduce toxicity effects of FSN. We use a combination of 29Si and 27Al solid-state magic angle spinning (MAS) NMR, Raman spectroscopy, and thermogravimetric analysis (TGA) to probe the surface and bulk structure and quantify the adsorption capacity and reactivity of the metal-doped FSN with respect to amino acid thermal condensation. Alanine was selected as the amino acid of choice for its simplicity and ubiquity in biochemical reactions. The results indicate that metal doping has a modest impact on the fumed silica molecular structure with a small decrease in amino acid adsorption capacity and thermal condensation reactivity as a function of increased metal doping.journal articleBand:5644 75 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Stability of multiple emulsions under shear stressMultiple liquid emulsions of the water in oil in water (W1/O/W2) type are used in a variety of consumer or technical applications, for instance in the encapsulation of certain active ingredients. The encapsulation process and release mechanisms of the inner phase of the carrier drops are important in order to properly process and formulate such liquid-liquid systems. In this work the stability and breakage of multiple W1/O/W2 emulsions under mechanical shear stress are investigated for emulsions with different surfactants and surfactant concentrations of the internal emulsion. Stressing the emulsions in a mechanical stirring process is compared to the membrane emulsification process. The membrane emulsification process results in higher encapsulation efficiencies than the stirring process. The emulsion droplets were subjected to shear stress below and above the critical capillary number for drop breakup. The results show that stable inner emulsions with sufficient surfactant concentrations increase the overall encapsulation efficiency for multiple emulsions subjected to shear stress, although the effect is not prominent. The depletion of the carrier oil droplets could be achieved for Ca numbers below the critical limit, reducing the encapsulation efficiency below 10 %. This shows that even a low shear stress can result in content release from the internal droplet phase. The experimental emulsion release study is supported by a numerical simulation of drop deformation and break-up under shear stress.journal articleBand:98Heft:1106 151 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Fine finishing of gears with high shape accuracyBesides high demands on surface integrity machining of gears aims on very low surface roughness and high shape accuracy. These properties will have positive impacts on the lifetime of gears. In this context the challenges of profile grinding of cylindrical gears by using elastic bonded grinding wheels are addressed. For this new gear fine finishing approach, the very high potential of the process is revealed by analyzing the influence of the grinding wheel specification and the machining parameters on surface finish. Results show that gears with high shape accuracy and very good surface finish with almost optical quality can be achieved.journal articleBand:62Heft:182 86 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Impact of fluid supply on energy efficiency and process performance in grindingAn approach is presented to evaluate the energy efficiency of grinding processes by the total specific energy in relation to the process limits, e.g. starting thermal damage at a certain specific removal rate. The paper deals with grinding experiments on hardened steel workpieces covering a broad range of different types of fluid supply nozzles, fluid flowrates, and removal rates with and without high pressure tool cleaning. In the investigations, process configurations were identified leading to high energy efficiency in combination with highest achievable removal rates. Furthermore, the results confirm that the process limit is significantly influenced by specifically adapted fluid supply conditions e.g. flowrate and jet speed.journal articleBand:68Heft:1125 146 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Implementation of parcel method for surface reactions in DSMC(Elsevier, 2019-05-06); ; ; ; The parcel concept in Direct Simulation Monte Carlo method has been added to the reaction algorithm to the DSMC solver in OpenFOAM to reduce computational demand. Parcel per cell is checked for different cell sizes and different parcel sizes to obtain the right cell size for a given system. At this cell size, diffusion of CO in O2 is simulated in a porous structure to ascertain the feasibility of this concept. After adding adsorption and reaction models, concentration profiles are obtained for different temperatures and different time steps. These profiles are compared with the single molecule algorithm written by Pesch et al. [14]. The local surface coverages and reaction rates are evaluated at a parcel size ranging from 10 to 100 to further validate the new approach. Computational time demand reduces by half at maximum parcel size to reach similar steady state results as that of the single molecule approach.journal articleBand:187135 107