Browsing by Author "Rosenkranz, Andreas"
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- ItemA critical assessment of surface texturing for friction and wear improvement(2017) Gachot, C.; Rosenkranz, Andreas; Hsu, S. M.; Costa, H. L.
- ItemAdditive Manufacturing in the Maritime Industry: A Perspective on Current Trends and Future Needs(2023) Garofalo, James; Shah, Raj; Thomas, Gavin; Shirvani, Khosro; Marian, Max; Rosenkranz, AndreasAdditive manufacturing (AM) has seen slow growth thus far in the maritime industry. Like other industries, maritime companies and institutions have started using AM for prototyping and product development needs but is now beginning to expand into production of end use parts and production tooling. The slow adoption can mainly be attributed to a previous lack of education in additive technology and strategies, current lack of reliability testing of additive machines in a marine environment, and the need for classification and certification of parts and machines before shipowners and crews will likely adopt for widespread use. This article provides a perspective of recent AM activities within the industry and discusses the need for research in key areas before widespread utilization can occur. Current use includes a recent push in maritime education, surveys of maritime workers and stakeholders, and fabrication of replacement parts, propellers, and boat hulls. Prospective key areas with the need for further research include 1) use-cases for replacement parts on ship, 2) economic feasibility of putting 3D printers on board, 3) standards, certification, and quality assurance, and 4) reliability and repeatability in a marine environment
- ItemAdditively manufactured MAX- and MXene-composite scaffolds for bone regeneration- recent advances and future perspectives(2023) Khabisi, Minufar Abdollahi; Shirini, Farhad; Shirini, Kasra; Khorsand, Hamid; Marian, Max; Rosenkranz, AndreasHuman bones can suffer from various injuries, such as fractures, bone cancer, among others, which has initiated research activities towards bone replacement using advanced bio-materials. However, it is still challenging to design bio-scaffolds with bone-inducing agents to regenerate bone defects. In this regard, MAX-phases and MXenes (early transition metal carbides and/or nitrides) have gained notable attention due to their unique hydrophilicity, bio-compatibility, chemical stability, and photothermal properties. They can be used in bone tissue engineering as a suitable replacement or reinforcement for common bio-materials (polymers, bio-glasses, metals, or hydroxyapatite). To fabricate bio-scaffolds, additive manufacturing is prospective due to the possibility of controlling porosity and creating complex shapes with high resolution. Until now, no comprehensive article summarizing the existing state-of-the-art related to bone scaffolds reinforced by MAX-phases and MXenes fabricated by additive manufacturing has been published. Therefore, our article addresses the reasons for using bone scaffolds and the importance of choosing the most suitable material. We critically discuss the recent developments in bone tissue engineering and regenerative medicine using MAX-phases and MXenes with a particular emphasis on manufacturing, mechanical properties, and bio-compatibility. Finally, we discuss the existing challenges and bottlenecks of bio-scaffolds reinforced by MAX-phases and MXenes before deriving their future potential.
- ItemBiomass-derived furfural conversion over Ni/CNT catalysts at the interface of water-oil emulsion droplets(2020) Herrera, C.; Pinto-Neira, J.; Fuentealba Patiño, Denis Alberto; Sepulveda, C.; Rosenkranz, Andreas; Gonzalez, M.; Escalona, Néstor
- ItemCatalytic performance of 2D-Mxene nano-sheets for the hydrodeoxygenation (HDO) of lignin-derived model compounds(2020) Blanco, E; Rosenkranz, Andreas; Espinoza-González, R; Fuenzalida, VM; Zhang, ZY; Suarez, S.; Escalona, N.
- ItemCombining multi-scale surface texturing and DLC coatings for improved tribological performance of 3D printed polymers(2023) Marian, Max; Zambrano, Dario F.; Rothammer, Benedict; Waltenberger, Valentin; Boidi, Guido; Krapf, Anna; Merle, Benoit; Stampfl, Jürgen; Rosenkranz, Andreas; Gachot, Carsten; Grützmacher, Philipp G.Polymer components fabricated by additive manufacturing typically show only moderate strength and low temperature stability, possibly leading to severe wear and short lifetimes especially under dry tribological sliding. To tackle these shortcomings, we investigated the combination of single- and multi-scale textures directly fabricated by digital light processing with amorphous diamond-like carbon (DLC) coatings. The topography of the samples and conformity of the coatings on the textures are assessed and their tribological behaviour under dry conditions is studied. We demonstrate that the surface textures have a detrimental tribological effect on the uncoated samples. This changes with the application of DLC coatings since friction substantially reduces and wear of the textures is not observed anymore. These trends are attributed to the protection of the underlying polymer substrate by the coatings and a reduced contact area. The best tribological performance is found for a coating with highest hardness and hardness-to-elasticity ratios. Moreover, multi-scale textures perform slightly better than single-scale textures due to a smaller real contact area. Summarizing, we verified that the high flexibility and low production costs of 3D printing combined with the excellent mechanical and tribological properties of DLC results in synergistic effects with an excellent performance under dry sliding conditions
- ItemEffect of Ni Metal Content on Emulsifying Properties of Ni/CNTox Catalysts for Catalytic Conversion of Furfural in Pickering Emulsions(2021) Herrera Hernández, Carla Pía; Pinto Neira, Josefa; Fuentealba Patiño, Denis Alberto; Sepúlveda, C.; Rosenkranz, Andreas; García-Fierro, J. L.; González, M.; Escalona, Néstor
- ItemEvaluation of DLC, MoS2, and Ti3C2T thin films for triboelectric nanogenerators(2022) Tremmel, Stephan; Luo, Xiongxin; Rothammer, Benedict; Seynstahl, Armin; Wang, Bo; Rosenkranz, Andreas; Marian, Max|Zhu, LaipanDue to their cost-effective fabrication, easy integration, and low frequency working range, triboelectric nanogenerators (TENGs) demonstrate tremendous potential in green energy harvesting to power smart devices and the internet of things (IoT). However, there is an urgent need to synergistically maximize their output and improve their durability to ensure a long-lasting high performance. This study aims at elucidating the performance of protective thin films deposited on the wear-prone PTFE surface of TENGs including doped and undoped, single- and multi-layer hydrogenated DLC films, MoS2 coatings fabricated by physical vapor deposition and multi-layer Ti3C2Tx (MXene) films. The deposited coatings are characterized by electron microscopy, and Raman spectroscopy. Their triboelectric performance is analyzed for TENGs operating in contact separation and freestanding sliding modes. We verified that MXenes outperformed the other films in contact separation mode due to the good electron gain ability of functional oxygen and fluorine groups. In sliding mode, the undoped a-C:H coating performed on a comparable level to the uncoated reference and superior to the tungsten-doped DLC and MoS2 films. The film withstood long-term tests without notable signs of wear; merely the output slowly decreased with time due to graphitization and thus potential material transfer to the mating body.
- ItemEvaluation of the surface fatigue behavior of amorphous carbon coatings through cyclic nanoindentation(2021) Weikert, Tim; Wartzack, Sandro; Baloglu, Maximiliano V.; Willner, Kai; Gabel, Stefan; Merle, Benoit; Pineda, Fabiola; Walczak, Magdalena; Marian, Max; Rosenkranz, Andreas; Tremmel, StephanDiamond-like carbon (DLC) coatings, frequently used to reduce wear and friction in machine components as well as on forming tools, are often subjected to cyclic loading. Doping of DLC coatings with metals or metal carbides as well as the usage of multilayer architectures represent promising approaches to enhance toughness, which is beneficial for the coatings' behavior under cyclic loading. In this study, we utilized cyclic nanoindentation to characterize the tribologically induced surface fatigue behavior of single-layer tungsten-doped (a-C:H:W) and multilayer silicon oxide containing (a-C:H:Si:O/a-C:H)25 amorphous carbon coatings under cyclic loading. Columnar growth was observed for both coatings by focused ion beam microscopy and scanning electron microscopy, while the multilayer architecture of the (a-C:H:Si:O/a-C:H)25 coating was verified by the silicon content using glow-discharge optical emission spectroscopy. In cyclic nanoindentation of the (a-C:H:Si:O/a-C:H)25 multilayer coating, stepwise small changes in indentation depth were observed over several indentation cycles. The surface fatigue process of the single-layer a-C:H:W covered a smaller number of indentation cycles and was characterized by an early steep increase of the static displacement signal. Microscopical analyses hint at grain deformation, sliding at columnar boundaries, and grain detachment as underlying fatigue mechanisms of the a-C:H:W coating, while the (a-C:H:Si:O/a-C:H)25 multilayer coating showed transgranular crack propagation and gradual fracturing. In case of the (a-C:H:Si:O/a-C:H)25 multilayer coating, superior indentation hardness (HIT) and indentation modulus (EIT) as well as a higher HIT3/EIT2 ratio suggest a higher resistance to plastic deformation. A high HIT3/EIT2 ratio, being an indicator for hindered crack initiation, combined with the capability of stress relaxation in soft layers contributed to the favorable surface fatigue behavior of the (a-C:H:Si:O/a-C:H)25 multilayer coating observed in this cyclic nanoindentation studies
- ItemFailure Analysis of Slurry Pump Impeller Fractured at Collahuasi Mine(2016) Ramos Moore, Esteban; Rosenkranz, Andreas
- ItemLaser Interference Patterning of Steel Surfaces - Influence on the Frictional Performance under Dry and Lubricated Sliding Conditions(2016) Rosenkranz, Andreas; Gachot, Carsten; Ramos Moore, Esteban; Mucklich, Frank
- ItemLayered 2D Nanomaterials to Tailor Friction and Wear in Machine Elements—A Review(2022) Marian, Max; Berman, Diana; Rota, Alberto; Jackson, Robert L.; Rosenkranz, AndreasRecent advances in 2D nanomaterials, such as graphene, transition metal dichalcogenides, boron nitride, MXenes, allow not only to discover several new nanoscale phenomena but also to address the scientific and industrial challenges associated with the design of systems with desired physical properties. One of the great challenges for mechanical systems is associated with addressing friction and wear problems in machine elements. In this review, the beneficial properties of layered 2D materials that enable the control of their tribological behavior and make them excellent candidates for efficient friction and wear reduction in dry-running and boundary lubricated machine components are summarized. The recent studies highlighting the successful implementation of 2D structures when used as solid lubricant coatings or reinforcement phases in composites for various machine components including sliding and rolling bearings, gears, and seals are overviewed. The examples presented in the studies demonstrate the great potential for 2D materials to address the energy-saving needs by friction and wear reduction.
- ItemMicrostructural and chemical characterization of the tribolayer formation in highly loaded cylindrical roller thrust bearings(2016) Gachot, Carsten; Hsu, ChiaJui; Suárez, Sebastián; Grützmacher, Philipp; Rosenkranz, Andreas; Stratmann, Andreas; Jacobs, Georg
- ItemNanometric thin films of non-doped diamond-like carbon grown on n-type (P-doped) silicon substrates as electrochemical electrodes(2018) Hevia, Samuel; Bejide, M.; Durán Lagos, Boris Guido; Rosenkranz, Andreas; Ruiz, H.M.; Favre Domínguez, Mario; Río Quero, Rodrigo del
- ItemNumerical micro-texture optimization for lubricated contacts : a critical discussion(2022) Marian, Max; Almqvist, Andreas; Rosenkranz, Andreas; Fillon, MichelDespite numerous experimental and theoretical studies reported in the literature, surface micro-texturing to control friction and wear in lubricated tribo-contacts is still in the trial-and-error phase. The tribological behaviour and advantageous micro-texture geometries and arrangements largely depend on the contact type and the operating conditions. Industrial scale implementation is hampered by the complexity of numerical approaches. This substantiates the urgent need to numerically design and optimize micro-textures for specific conditions. Since these aspects have not been covered by other review articles yet, we aim at summarizing the existing state-of-the art regarding optimization strategies for micro-textures applied in hydrodynamically and elastohydrodynamically lubricated contacts. Our analysis demonstrates the great potential of optimization strategies to further tailor micro-textures with the overall aim to reduce friction and wear, thus contributing toward an improved energy efficiency and sustainability.
- ItemPredicting EHL film thickness parameters by machine learning approaches(2022) Marian, Max; Mursak, Jonas; Bartz, Marcel; Profito, Francisco J.; Rosenkranz, Andreas; Wartzack, SandroNon-dimensional similarity groups and analytically solvable proximity equations can be used to estimate integral fluid film parameters of elastohydrodynamically lubricated (EHL) contacts. In this contribution, we demonstrate that machine learning (ML) and artificial intelligence (AI) approaches (support vector machines, Gaussian process regressions, and artificial neural networks) can predict relevant film parameters more efficiently and with higher accuracy and flexibility compared to sophisticated EHL simulations and analytically solvable proximity equations, respectively. For this purpose, we use data from EHL simulations based upon the full-system finite element (FE) solution and a Latin hypercube sampling. We verify that the original input data are required to train ML approaches to achieve coefficients of determination above 0.99. It is revealed that the architecture of artificial neural networks (neurons per layer and number of hidden layers) and activation functions influence the prediction accuracy. The impact of the number of training data is exemplified, and recommendations for a minimum database size are given. We ultimately demonstrate that artificial neural networks can predict the locally-resolved film thickness values over the contact domain 25-times faster than FE-based EHL simulations (R² values above 0.999). We assume that this will boost the use of ML approaches to predict EHL parameters and traction losses in multibody system dynamics simulations.
- ItemRoadmap for 2D materials in biotribological/biomedical applications – A review(2022) Marian, Max; Berman, Diana; Nečas, David; Emami, Nazanin; Ruggiero, Alessandro; Rosenkranz, AndreasThe human body involves a large number of systems subjected to contact stresses and thus experiencing wear and degradation. The limited efficacy of existing solutions constantly puts a significant financial burden on the healthcare system, more importantly, patients are suffering due to the complications following a partial or total system failure. More effective strategies are highly dependent on the availability of advanced functional materials demonstrating excellent tribological response and good biocompatibility. In this article, we review the recent progress in implementing two-dimensional (2D) materials into bio-applications involving tribological contacts. We further summarize the current challenges for future progress in the field.
- ItemRole of electrolytes on the electrochemical characteristics of Fe3O4/MXene/RGO composites for supercapacitor applications(2020) Arun, T.; Mohanty, A.; Rosenkranz, Andreas; Wang, B.; Yu, J.; Morel, M. J.; Udayabhaskar, R.; Hevia, Samuel; Akbari Fakhrabadi, A.; Mangalaraja, R. V.; Ramadoss, A.
- ItemSimultaneous deposition of carbon nanotubes and decoration with gold-palladium nanoparticles by laser-induced forward transfer(2016) Lasserre, Federico; Rosenkranz, Andreas; Souza Carmona, Nicolás; Roble Albeal, Martín Cristián; Ramos Moore, Esteban; Díaz, Donovan; Mücklich, Frank