Article
Polymer Science
Ales Gosar, Igor Emri, Jernej Klemenc, Marko Nagode, Simon Oman
Summary: This study investigates the vibration-damping properties of prestressed granular material, and finds that granular form provides better vibration-damping performance compared to bulk material. This improvement is achieved through the interaction of two effects: the pressure-frequency superposition principle at the molecular scale and the physical interactions between the granules (force-chain network) at the macro scale. Further improvements can be achieved by varying the material of the granules and applying a lubricant to facilitate reorganization of the force-chain network.
Article
Construction & Building Technology
Ferhat Cecen, Bekir Aktas, Hakan Ozturk, M. Burhan Navdar, Irfan S. Ozturk
Summary: The study demonstrates that the new LCR concrete sleepers have higher resistance to repeated impact loads and show higher residual strength, which are expected to play a role in extending the service life of railway components, reducing maintenance needs, and minimizing harmful environmental effects.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Liga Jasulaneca, Alexander I. Livshits, Raimonds Meija, Jelena Kosmaca, Raitis Sondors, Matiss M. Ramma, Daniels Jevdokimovs, Juris Prikulis, Donats Erts
Summary: Electrostatically actuated nanoelectromechanical (NEM) switches show promise for sharply defined ON/OFF states, high ON/OFF current ratio, low power consumption, and compact design. The challenge lies in fabricating single nanowire-based NEM switches. This study demonstrates the application of CuO nanowires as active elements in NEM switches and validates theoretical modeling for scalable integration of bottom-up synthesized nanowires in NEMS.
Article
Construction & Building Technology
Mahmoud T. Nawar, Ayman El-Zohairy, Hassan M. Maaly, Mohammed Husain, Islam Salama, Eslam Mousa
Summary: The flexural behavior of externally prestressed composite steel-concrete I-beams with a single and double corrugated web was investigated both experimentally and numerically. The experimental results showed that using a single corrugated web was more efficient in shear buckling resistance than using a double corrugated web with the same equivalent web thickness. The ABAQUAS software package was used to simulate the nonlinear behavior of the beams, and a parametric study was carried out to investigate the effect of various parameters on the behavior of the composite beams with single and double corrugated webs. Using stiffeners as deviators to maintain the prestressed tendon positions improved the beam capacity and performance.
Article
Polymer Science
Lin Xu, Samuel C. Lamont, Tao Li, Ying Zhang, Wenlong Pan, Chongyi Gao, Chen Zhu, Si Chen, Hongwei Hu, Jianning Ding, Franck J. Vernerey
Summary: We investigated the mechanical properties of a magnetic temperature-sensitive hydrogel with varying concentrations of covalent and physical cross-linking. Increasing the nanoclay content improved both strength and toughness in the double network materials due to the strong viscoplastic behavior of the physical nanoclay network. Our findings suggest that the yield-stress behavior of the nanoclay network and load-sharing interactions between the PNIPAAm and nanoclay are responsible for the observed trends. Additionally, we found a strong correlation between the mass ratio of covalent cross-linker used and fractional percolation of the PNIPAAm network.
Article
Construction & Building Technology
Keun-Hyeok Yang, Ju-Hyun Mun, Chae-Rim Im
Summary: This study investigated the axial and shear behaviors of a seismic damping isolation unit (SDI) developed to improve the seismic resistance of suspended ceiling structures. The results showed that the presence of a spring and higher prestressed force increased the ductility ratio and equivalent damping coefficient of the SDI. Additionally, the specimens subjected to monotonic loading exhibited higher ductility ratio compared to those subjected to cyclic loading. The JIS B 2704-1 and AISC specifications accurately estimated the tensile strength of the SDI specimens under monotonic loading but overestimated it under cyclic loading.
Article
Mechanics
Lili Hu, Peng Feng
Summary: The use of PS CFRP technology effectively enhances the buckling resistance of steel columns. Axial and eccentric compression tests were conducted under different conditions, analyzing the buckling capacity and failure modes, and further establishing a model of the buckling mechanism.
COMPOSITE STRUCTURES
(2021)
Review
Biochemistry & Molecular Biology
Pengguang Wang, Qingyu Liao, Hongbin Zhang
Summary: Polysaccharides, as major components of living organisms, have been widely studied and used in the design of double-network hydrogels due to their rich sources and desirable properties.
Article
Materials Science, Multidisciplinary
Huan Cao, Qijian Zhang, Hua Li, Jianmei Lu
Summary: A butyl chain-substituted molecule NACB was designed and fabricated as a ternary memory device with well-defined crystalline characteristics and tri-current states. The switching mechanism of the device originated from isomerization change and charge trap double mechanisms. The low write and read voltage, along with ternary data storage abilities, suggest potential for portable, low-power consumption and super-high density memory storage.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Construction & Building Technology
Larisa Garcia-Ramonda, Luca Pela, Pere Roca, Guido Camata
Summary: Recent research has shown that Steel Reinforced Grout (SRG) is an excellent solution for strengthening masonry structures. The use of SRG with limited fabric density ensures a good textile-matrix interlocking, preventing failure due to slippage or debonding.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Yusuf B. Habibullah, Teruya Ishihara
Summary: This study investigates second harmonic generation (SHG) from metasurfaces composed of split ring, heptagon, and triangle cross-polarized double resonant resonators through experimental and numerical methods. The triangular structure array shows the most efficient SHG. Experimental observations are reasonably explained through theoretical evaluation considering the overlapping integral of nonlinear polarization and the microscopic field distribution on the metal surface at the SHG frequency, accounting for the phase relation between the two fields.
Article
Nanoscience & Nanotechnology
Mahmoud Ebrahimi, Li Zhang, Qudong Wang, Hao Zhou, Wenzhen Li
Summary: The research showed that the damping behavior of AZ91D alloy can be significantly improved by the CEC process and the addition of CNTs, particularly at high temperatures. Additionally, while the addition of 0.5 wt% CNTs may decrease room temperature damping, the performance can be enhanced with the right amount of CNTs added.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Mechanics
Lior Medina
Summary: In this study, an expanded dynamic model of an electrostatically actuated double beam metastructure, consisting of geometrically different beams, was formulated and solved. It was found that weakly coupled and geometrically different sub-structures can exhibit global tristability under nonlinear, displacement-dependent, electrostatic actuation and bistability under mechanical, displacement-independent load. The stability of the structures was established using energy method, Lyapunov stability sweep, and quasi-static finite element simulations.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2023)
Article
Engineering, Civil
Lili Hu, Peng Feng
Summary: This paper theoretically analyzes the symmetrical global buckling behavior of imperfect prestressed CFRP laminate-reinforced steel columns with two hinged supports, and proposes calculation methods for the buckling capacity and the optimal CFRP initial prestressing force and maximum buckling capacity. Finally, a design method for PCRSCs and a design example are provided.
JOURNAL OF COMPOSITES FOR CONSTRUCTION
(2022)
Article
Biochemical Research Methods
Stefan Mommer, Nina Warner, Caroline Lienert
Summary: This study advances TL/ITL chemistry by introducing reactive side groups to the ITL heterocycle in the gamma-position. The γ-functional ITL exhibits orthogonal and enhanced reactivity, introducing a new functional handle to the biological substrate.
BIOCONJUGATE CHEMISTRY
(2023)
Article
Physics, Applied
Miao-Hsuan Chien, Mostafa M. Shawrav, Kurt Hingerl, Philipp Taus, Markus Schinnerl, Heinz D. Wanzenboeck, Silvan Schmid
Summary: This work presents a new chemical composition characterization method for direct-write focused electron beam-induced deposition (FEBID) gold nanostructures, demonstrating the possibility of characterizing the carbon content through differences in optical absorption and nanomechanical resonator frequency detuning. Post-purification with water successfully reduced the carbon content, offering a new technique for chemical analysis of nanostructures.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Analytical
Seoho Jung, Roland Hauert, Miroslav Haluska, Cosmin Roman, Christofer Hierold
Summary: By using Ar-ion etching to remove the top layer of the electrode surface before nanotube placement, the contact resistance at the nanotube-metal interface can be significantly reduced. This results in a tenfold decrease in the median ON-resistance of transistors and a more than two orders of magnitude decrease in the interquartile range of resistance values.
SENSORS AND ACTUATORS B-CHEMICAL
(2021)
Article
Electrochemistry
Katrina Klosel, Salvador Pane, Ian A. Mihailovic, Christofer Hierold
Summary: A method of template assisted electrochemical deposition is proposed for the synthesis of Bi2Se3 micropillars with controlled thickness and stoichiometry. The optimized conditions involve modifying the electrolyte composition and introducing resting pulses during the plating process. The resulting micropillars exhibit orthogonal structure and desirable electrical conductivity and Seebeck coefficient, demonstrating their potential for thermoelectric applications.
ELECTROCHIMICA ACTA
(2022)
Article
Optics
Zubair Buch, Silvan Schmid
Summary: This study investigates the internal optical forces emerging from plasmonic interactions in gold nanodisc, nanocube, and nanobar dimers using the finite element method. The results demonstrate a direct correlation between electric-field enhancement and optical forces, with the largest magnitude observed in nanocube dimers. Furthermore, the optical forces can be further amplified by increasing the optical power of the excitation source. The strength of optical forces is found to be governed by the magnitude of polarization density on the nanoparticles, which can be adjusted by modifying the nanoparticle geometry and source wavelength. Overall, the findings highlight the significance of nanoparticle geometry and inter-dimer distance in optimizing optical forces in plasmonic dimers.
Article
Nanoscience & Nanotechnology
Stefan Nedelcu, Kishan Thodkar, Christofer Hierold
Summary: This article reports a customizable, portable, battery-operated, wireless platform for interfacing high-sensitivity nanoscale sensors, aiming to improve spatiotemporal measurement coverage of physical parameters. The platform has a wide current range and high versatility, suitable for signal acquisition from resistive nanosensors, with overall low power consumption, making it highly suitable for various sensing applications within the context of IoT.
MICROSYSTEMS & NANOENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
Jian Zhang, Mickael L. Perrin, Luis Barba, Jan Overbeck, Seoho Jung, Brock Grassy, Aryan Agal, Rico Muff, Rolf Bronnimann, Miroslav Haluska, Cosmin Roman, Christofer Hierold, Martin Jaggi, Michel Calame
Summary: The rapid localization and characterization of nanomaterials is crucial for quality control and industrial adoption. This study presents a high-throughput method for quickly identifying nanomaterials using high-speed Raman imaging and deep learning analysis, along with an optimized scanning strategy.
MICROSYSTEMS & NANOENGINEERING
(2022)
Article
Engineering, Biomedical
Kai Petersdorff-Campen, Matthias A. Dupuch, Konstantinos Magkoutas, Mirko Meboldt, Christofer Hierold, Marianne Schmid Daners
Summary: This study demonstrates the integration of pressure sensors into a ventricular assist device, allowing continuous and accurate measurement of left ventricular pressure. The developed sensor model improves measurement accuracy by eliminating the influence of flow inside the device. This has significant implications for the validation of physiological control concepts in vivo.
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
M. G. Bartmann, M. Sistani, N. Luhmann, S. Schmid, E. Bertagnolli, A. Lugstein, J. Smoliner
Summary: Near-infrared detection is widely used in various applications and this study presents a scalable and CMOS compatible bolometer-type detector using Ge nanowires. The experimental results show that by implementing Ge nanowires on a low thermal conducting and highly absorptive membrane, a near-infrared sensor element can be achieved. Heat transport simulations and lock-in measurements were used to optimize the device and benchmark its performance.
Article
Physics, Multidisciplinary
Hendrik Kahler, Daniel Platz, Silvan Schmid
Summary: This paper presents a model for the coupling of MHz frequency resonators through surface acoustic waves (SAWs), which is validated by finite element method simulations and recent experiments. Unlike the well-known strain-induced spring-like coupling, the coupling via SAWs is both dispersive and dissipative, which can be utilized to achieve high quality phonon cavities.
COMMUNICATIONS PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Markus Piller, Johannes Hiesberger, Elisabeth Wistrela, Paolo Martini, Niklas Luhmann, Silvan Schmid
Summary: Researchers investigated NEMS trampoline resonators made of silicon nitride as thermal IR detectors and found that they have an enhanced responsivity compared to state-of-the-art SiN drums. The characterized NEMS trampoline IR detectors showed a sensitivity in terms of noise equivalent power (NEP) of 7 pW/v Hz and a thermal response time as low as 4 ms. The detector area featured an impedance-matched metal thin-film absorber with a spectrally flat absorption of 50% over the entire mid-IR spectral range from 1 to 25 μm.
IEEE SENSORS JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Hendrik Kaehler, Holger Arthaber, Robert Winkler, Robert G. West, Ioan Ignat, Harald Plank, Silvan Schmid
Summary: One challenge in nanoelectromechanical systems (NEMS) is the efficient transduction of tiny resonators. In this study, an electromechanical transduction method based on surface acoustic waves (SAWs) is presented, which successfully transduces freestanding nanomechanical platinum-carbon pillar resonators in the first-order bending and compression mode.
Article
Chemistry, Multidisciplinary
Niklas Luhmann, Robert G. West, Josiane P. Lafleur, Silvan Schmid
Summary: We propose a new method for quantitatively analyzing mixtures of semivolatile chemical compounds by integrating thermal desorption with nano electromechanical infrared spectroscopy (NEMS-IR-TD). In this technique, the analyte mixture is deposited on the surface of a NEMS sensor via nebulization and then desorbed under vacuum using heating. The desorption process is monitored in situ via infrared spectroscopy and thermogravimetric analysis, enabling selective identification and analysis of the mixture.
Article
Nanoscience & Nanotechnology
Kostas Kanellopulos, Robert G. West, Silvan Schmid
Summary: Understanding light-matter interaction at the nanoscale is crucial, and this study presents a nanomechanical photothermal sensing platform for analyzing individual nanoabsorbers. The absorption properties of gold nanorods are resolved, including their surface plasmon resonances. The analysis reveals the role of electron scattering and the interaction between nanoabsorbers and nanoresonators, highlighting the exceptional sensitivity of nanomechanical photothermal spectroscopy.
Proceedings Paper
Engineering, Electrical & Electronic
Morten Vollmann, Cosmin Roman, Christofer Hierold
Summary: A new model based on harmonic balancing is used to predict the resonance peak shape and extract pre-strain and gauge factors of carbon nanotube resonators. The model is able to separate different current contributions and agrees well with experimental measurements.
2022 IEEE 35TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS CONFERENCE (MEMS)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Johannes Weichart, Marcel Ott, Thomas Burger, Christofer Hierold
Summary: Advanced tactile sensing plays a crucial role in enabling more interactive and flexible robotics or prosthetics. This study proposes a sensing technology that replicates the human sense of touch by manufacturing highly sensitive tactile sensors in dense arrays on a flexible substrate. The characterization of the sensor array and its readout electronics reveals that the sensors can resolve capacitance changes with high precision and without crosstalk. The study also demonstrates that the sensors can accurately detect and measure 3D forces.
2022 IEEE 35TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS CONFERENCE (MEMS)
(2022)
