Browsing by Author "Rosenkranz, Andreas"
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- 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
- ItemFailure Analysis of Slurry Pump Impeller Fractured at Collahuasi Mine(2016) Ramos Moore, Esteban; Rosenkranz, Andreas
- 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.
- ItemRapid Thermal Characterization of Graphene Oxide-Nanocalorimetry as a Pathway for Novel Insights in Tribology(2019) Woll, Karsten; Neuhauser, Tobias; Acuna, Camilo; Diaz-Droguett, Donovan; Rosenkranz, AndreasThe use of solid lubricants such as graphene, graphene oxide, and other nanoparticles have gained notable attention in the tribological community to reduce friction and wear thus aiming at improved energy efficiency and sustainability. Tribological experiments unify rather extreme conditions such as high contact pressures, small contact areas, relative sliding motion, and rapid heating. This combination leads to mechanically- and/or thermally induced chemical, structural and microstructural modifications of the lubricating nanoparticles during rubbing thus altering their material's properties. Due to the high sensitivity, we propose nanocalorimetry as the method of choice to shed more light on the thermally-induced processes and changes. As a model material for solid lubricants, we explore the transitions of graphene oxide under heating with 1000 degrees C/s up to 600 degrees C using quasi-adiabatic nanocalorimetry. We identify a strong exothermic runaway reaction at 317 degrees C. This runaway is preceded by exothermic reactions between 75-125 degrees C, which are correlated with the release of intercalated species and the formation of CO and CO2.
- ItemReactive oxygen species-dependent anti-extended spectrum β-lactamases activity of multi-layer Ti3C2Tx: A novel approach for treating successfully P. aeruginosa and K. pneumoniae(2024) Rajivgandhi, Govindan; Margoni, Mudaliar Mahesh; Chelliah, Chenthis Kanisha; Rosenkranz, Andreas; Gnanasekaran, Chackaravarthi; Ramachandran, Vijayan; Ramachandran, Govindan; Bhuyan, Heman; Adell, Jose F.; Maruthupandy, Muthuchamy; Manoharan, Natesan; Akbari-Fakhrabadi, Ali; Quero, FranckMulti-layer (ML) Ti3C2Tx was investigated regarding its anti-extended spectrum beta-lactamases (ESBLs) activity and in-vivo toxicity. Powder X-ray diffraction of ML-Ti3C2Tx confirmed the successful etching of Ti3AlC2 (MAX) to form ML-Ti3C2Tx as well as the presence of -OH,-F and-O surface terminations. Fourier-transform infrared spectroscopy and thermal decomposition verified the presence of its typical chemical bonds and moieties including Ti-O, O-H, C-H, C--O, and -OH, which further confirmed the successful synthesis of ML-Ti3C2Tx. Scanning and transmission electron microscopy demonstrated its multi-layered structure, while X-ray photoelectron spectroscopy revealed the presence of various photoelectron peaks with binding energy positions corresponding to O1s, C1s, Ti 2p, and F1s, indicating the existence of distinct surface terminations and oxidation states. The E-strip synergy and micro-iodometric methods suggested that ML-Ti3C2Tx possesses excellent beta-lactamases inactivation with 96 and 94 % inhibition at 90 mu g/mL against P. aeruginosa (MN310553) and K. pneumoniae (MN368594), respectively. Concentration-dependent reactive oxygen species (ROS) generation of ML-Ti3C2Tx decreased notably bacterial cell growth as well as its response to beta-lactamase resistances. Moreover, intercellular damage and outer cell wall rupture through external proliferation forces of sharp-edged ML-Ti3C2T were confirmed by confocal laser and scanning electron microscopy. Molecular docking suggested that Ti3C2Tx induced effective inhibition of TEM1 beta-lactamase, providing insights for future development of drug-resistant ESBLs with gene control. Finally, the evaluation of the in-vivo toxicity of the synthesized ML-Ti3C2Tx against brine shrimp Artemia revealed their non-toxicity up to a maximum concentration of 150 mu g/mL and 24 h exposure time.
- 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.
- ItemTi3C2Tx and Mo2TiC2Tx MXenes as additives in synovial fluids - towards an enhanced biotribological performance of 3D-printed implants(2024) Marian, Max; Esteban, Cotty D. Quiroz; Zambrano, Dario F.; Ramteke, Sangharatna M.; Grez, Jorge Ramos; Wyatt, Brian C.; Patenaude, Jacob; Wright, Bethany G.; Anasori, Babak; Rosenkranz, AndreasSynovial joints, critical for limb biomechanics, rely on sophisticated lubrication systems to minimize wear. Disruptions, whether from injury or disease, often necessitate joint replacements. While additive manufacturing offers personalized implants, ensuring wear resistance remains a challenge. This study delves into the potential of Ti3C2Tx 3 C 2 T x and Mo2TiC2Tx 2 TiC 2 T x nanosheets in mitigating wear of additively manufactured cobalt-chromium tungsten alloy substrates when incorporated as additives into synovial fluid. The colloidal solutions demonstrate an excellent stability, a crucial factor for reproducible assays and potential clinical applicability. Analysis of contact angles and surface tensions reveals MXene-induced alterations in substrate wettability, while maintaining their general hydrophilic character. Viscosity analysis indicates that MXene addition reduces the dynamic viscosity, particularly at higher concentrations above 5 mg/mL, thus enhancing dispersion and lubrication properties. Friction and wear tests demonstrate a dependency on the MXene concentration, while Ti3C2Tx 3 C 2 T x exhibits stable friction coefficients and up to 77 % wear reduction at 5 mg/mL, which was attributed to the formation of a wear- protecting tribo-film (amorphous carbon and MXene nano-sheets). Our findings suggest that Ti3C2Tx, 3 C 2 T x , when supplied in favorable concentrations, holds promise for reducing wear in biotribological applications, offering avenues for future research into optimizing MXene utilization in load-bearing joint replacements and other biomedical devices.
- ItemTi3C2Tx-UHMWPE Nanocomposites-Towards an Enhanced Wear-Resistance of Biomedical Implants(2024) Rothammer, Benedict; Feile, Klara; Werner, Siegfried; Frank, Rainer; Bartz, Marcel; Wartzack, Sandro; Schubert, Dirk W.; Drummer, Dietmar; Detsch, Rainer; Wang, Bo; Rosenkranz, Andreas; Marian, MaxThere is an urgent need to enhance the mechanical and biotribological performance of polymeric materials utilized in biomedical devices such as load-bearing artificial joints, notably ultrahigh molecular weight polyethylene (UHMWPE). While two-dimensional (2D) materials like graphene, graphene oxide (GO), reduced GO, or hexagonal boron nitride (h-BN) have shown promise as reinforcement phases in polymer matrix composites (PMCs), the potential of MXenes, known for their chemical inertness, mechanical robustness, and wear-resistance, remains largely unexplored in biotribology. This study aims to address this gap by fabricating Ti3C2Tx-UHMWPE nanocomposites using compression molding. Primary objectives include enhancements in mechanical properties, biocompatibility, and biotribological performance, particularly in terms of friction and wear resistance in cobalt chromium alloy pin-on-UHMWPE disk experiments lubricated by artificial synovial fluid. Thereby, no substantial changes in the indentation hardness or the elastic modulus are observed, while the analysis of the resulting wettability and surface tension as well as indirect and direct in vitro evaluation do not point towards cytotoxicity. Most importantly, Ti3C2Tx-reinforced PMCs substantially reduce friction and wear by up to 19% and 44%, respectively, which was attributed to the formation of an easy-to-shear transfer film.