Well-defined nanostructuring with designable anodic aluminum oxide template. - In: Nature Communications, ISSN 2041-1723, Bd. 13 (2022), 2435, S. 1-11
Well-defined nanostructuring over size, shape, spatial configuration, and multi-combination is a feasible concept to reach unique properties of nanostructure arrays, while satisfying such broad and stringent requirements with conventional techniques is challenging. Here, we report designable anodic aluminium oxide templates to address this challenge by achieving well-defined pore features within templates in terms of in-plane and out-of-plane shape, size, spatial configuration, and pore combination. The structural designability of template pores arises from designing of unequal aluminium anodization rates at different anodization voltages, and further relies on a systematic blueprint guiding pore diversification. Starting from the designable templates, we realize a series of nanostructures that inherit equal structural controllability relative to their template counterparts. Proof-of-concept applications based on such nanostructures demonstrate boosted performance. In light of the broad selectivity and high controllability, designable templates will provide a useful platform for well-defined nanostructuring.
https://doi.org/10.1038/s41467-022-30137-6
Direct data-driven forecast of local turbulent heat flux in Rayleigh-Bénard convection. - In: Physics of fluids, ISSN 1089-7666, Bd. 34 (2022), 4, 045106, S. 045106-1-045106-14
A combined convolutional autoencoder-recurrent neural network machine learning model is presented to directly analyze and forecast the dynamics and low-order statistics of the local convective heat flux field in a two-dimensional turbulent Rayleigh-Bénard convection flow at Prandtl number Pr=7 and Rayleigh number Ra=10^7. Two recurrent neural networks are applied for the temporal advancement of turbulent heat transfer data in the reduced latent data space, an echo state network, and a recurrent gated unit. Thereby, our work exploits the modular combination of three different machine learning algorithms to build a fully data-driven and reduced model for the dynamics of the turbulent heat transfer in a complex thermally driven flow. The convolutional autoencoder with 12 hidden layers is able to reduce the dimensionality of the turbulence data to about 0.2% of their original size. Our results indicate a fairly good accuracy in the first- and second-order statistics of the convective heat flux. The algorithm is also able to reproduce the intermittent plume-mixing dynamics at the upper edges of the thermal boundary layers with some deviations. The same holds for the probability density function of the local convective heat flux with differences in the far tails. Furthermore, we demonstrate the noise resilience of the framework. This suggests that the present model might be applicable as a reduced dynamical model that delivers transport fluxes and their variations to coarse grids of larger-scale computational models, such as global circulation models for atmosphere and ocean.
https://doi.org/10.1063/5.0087977
Stationary, continuous, and sequential surface-enhanced raman scattering sensing based on the nanoscale and microscale polymer-metal composite sensor particles through microfluidics: a review. - In: Advanced optical materials, ISSN 2195-1071, Bd. 10 (2022), 7, 2102757, S. 1-25
Surface-enhanced Raman scattering (SERS) is a label-free and accurate analytical technique for the detection of a broad range of various analytes such as, biomolecules, pesticides, petrochemicals, as well as, cellular and other biological systems. A key component for the SERS analysis is the substrate which is required to be equipped with plasmonic features of metal nanostructures that directly interact with light and targeted analytes. Either metal nanoparticles can be deposited on the solid support (glass or silicon) which is suitable for stationary SERS analysis or dispersed in the solution (freely moving nanoparticles). Besides these routinely utilizing SERS substrates, polymer-metal composite particles are promising for sustained SERS analysis where metal nanoparticles act as plasmon-active (hence SERS-active) components and polymer particles act as support to the metal nanoparticles. Composite sensor particles provide 3D interaction possibilities for analytes, suitable for stationary, continuous, and sequential analysis, and they are reusable/regenerated. Therefore, this review is focused on the experimental procedures for the development of multiscale, uniform, and reproducible composite sensor particles together with their application for SERS analysis. The microfluidic reaction technique is highly versatile in the production of uniform and size-tunable composite particles, as well as, for conducting SERS analysis.
https://doi.org/10.1002/adom.202102757
Designing and implementing accepted business processes : the effects of self-healing capabilities of a process and the associated loss of control on process acceptance
Akzeptierte Geschäftsprozesse gestalten und implementieren : die Effekte von Selbstheilungsfähigkeiten eines Prozesses und des damit verbundenen Kontrollverlustes auf die Prozessakzeptanz. - In: HMD, ISSN 2198-2775, Bd. 59 (2022), 2, S. 572-587
Gemäß der Prozessakzeptanztheorie hat die Akzeptanz von Prozessen einen Einfluss auf deren korrekte Ausführung. Sollen Abweichungen und Manipulationen in der Prozessausführung, die auch ethisch negativ konnotiert sein können, verhindert werden, ist es notwendig zu verstehen, welche Faktoren einen Einfluss auf die Akzeptanz aufweisen. In der vorliegenden Arbeit wird der Einfluss von Selbstheilungsfähigkeiten im Prozess sowie der Einfluss eines damit verbundenen Verlustes der Kontrolle der Beteiligten über die Daten in zwei Experimenten untersucht. Dadurch, dass ein Algorithmus die Kontrolle über den Prozess übernimmt, ist hier die digitale Ethik betroffen. Die Basis für das Experiment bildet ein generischer Einkaufsprozess, der online über Amazon’s Mechanical Turk bereitgestellt wird. Die Prozessakzeptanz wird mit Hilfe eines Fragebogens aufgeteilt in die drei Dimensionen der Einstellung (kognitiv, affektiv, konativ) gemessen. Das erste Experiment zeigt, dass es einen signifikanten Unterschied in der Akzeptanz von Prozesse mit und ohne Selbstheilungsmechanismen gibt. Die Ergebnisse der Tests deuten darauf hin, dass die Selbstheilung nicht automatisch besser akzeptiert wird als wiederholte manuelle Anstrengungen. Dieses Ergebnis ist auch praktisch sehr wichtig, denn automatisierte Rekonstruktionen nehmen heute eine wichtige Rolle in der IT-gestützten Ausführung von Geschäftsprozessen ein. Eine vorläufige Erklärung ist, dass ein Verlust der Kontrolle der Teilnehmer über die Daten zu diesem scheinbar kontra-intuitiven Ergebnis führt. Im zweiten Experiment wird daher der Kontrollverlust untersucht. Es konnte dahingehend keine Signifikanz festgestellt werden, allerdings deutet die gemessene Teststärke darauf hin, dass das gewählte Testdesign möglicherweise nicht sensibel genug war, solche Unterschiede messen zu können. Weitere Untersuchungen sind daher nötig.
https://link.springer.com/content/pdf/10.1365/s40702-022-00856-x.pdf
Perceptual matching of room acoustics for auditory augmented reality in small rooms - literature review and theoretical framework. - In: Trends in hearing, ISSN 2331-2165, Bd. 26 (2022), S. 1-22
For the realization of auditory augmented reality (AAR), it is important that the room acoustical properties of the virtual elements are perceived in agreement with the acoustics of the actual environment. This perceptual matching of room acoustics is the subject reviewed in this paper. Realizations of AAR that fulfill the listeners? expectations were achieved based on pre-characterization of the room acoustics, for example, by measuring acoustic impulse responses or creating detailed room models for acoustic simulations. For future applications, the goal is to realize an online adaptation in (close to) real-time. Perfect physical matching is hard to achieve with these practical constraints. For this reason, an understanding of the essential psychoacoustic cues is of interest and will help to explore options for simplifications. This paper reviews a broad selection of previous studies and derives a theoretical framework to examine possibilities for psychoacoustical optimization of room acoustical matching.
https://doi.org/10.1177/23312165221092919
Recent advances in 2D heterostructures as advanced electrode materials for potassium-ion batteries. - In: Small structures, ISSN 2688-4062, Bd. 3 (2022), 3, 2100221, insges. 19 S.
Owing to the cost-effectiveness, Earth abundance, and suitable redox potential, potassium-ion batteries (PIBs) stand out as one of the best candidates for large-scale energy storage systems. However, the large radius of K+ and the unsatisfied specific capacity are the main challenges for their commercial applications. To address these challenges, constructing heterostructures by selecting and integrating 2D materials as host and other materials as guest are proposed as an emerging strategy to obtain electrode materials with high capacity and long lifespan, thus improving the energy storage capability of PIBs. Recently, numerous studies are devoted to developing 2D-based heterostructures as electrode materials for PIBs, and significant progress is achieved. However, there is a lack of a review article for systematically summarizing the recent advances and profoundly understanding the relationship between heterostructure electrodes and their performance. In this sense, it is essential to outline the promising advanced features, to summarize the electrochemical properties and performances, and to discuss future research focuses about 2D-based heterostructures in PIBs.
https://doi.org/10.1002/sstr.202100221
Aligned deposition of bottom-up grown nanowires by two-directional pressure-controlled contact printing. - In: Nanotechnology, ISSN 1361-6528, Bd. 33 (2022), 23, 235301, S. 1-9
Aligned large-scale deposition of nanowires grown in a bottom-up manner with high yield is a persisting challenge but required to assemble single-nanowire devices effectively. Contact printing is a powerful strategy in this regard but requires so far adequate adjustment of the tribological surface interactions between nanowires and target substrate, e.g. by microtechnological surface patterning, chemical modifications or lift-off strategies. To expand the technological possibilities, we explored two-directional pressure-controlled contact printing as an alternative approach to efficiently transfer nanowires with controlled density and alignment angle onto target substrates through vertical-force control. To better understand this technology and the mechanical behavior of nanowires during the contact printing process, the dynamic bending behavior of nanowires under varying printing conditions is modeled by using the finite element method. We show that the density and angular orientation of transferred nanowires can be controlled using this three-axis printing approach, which thus enables potentially a controlled nanowire device fabrication on a large scale.
https://doi.org/10.1088/1361-6528/ac56f8
A method using generative adversarial networks for robustness optimization. - In: ACM transactions on modeling and computer simulation, ISSN 1558-1195, Bd. 32 (2022), 2, S. 12:1-12:22
The evaluation of robustness is an important goal within simulation-based analysis, especially in production and logistics systems. Robustness refers to setting controllable factors of a system in such a way that variance in the uncontrollable factors (noise) has minimal effect on a given output. In this paper, we present an approach for optimizing robustness based on deep generative models, a special method of deep learning. We propose a method consisting of two Generative Adversarial Networks (GANs) to generate optimized experiment plans for the decision factors and the noise factors in a competitive, turn-based game. In a case study, the proposed method is tested and compared to traditional methods for robustness analysis including Taguchi method and Response Surface Method.
https://doi.org/10.1145/3503511
Effect of C60 fullerene on recovery of muscle soleus in rats after atrophy induced by achillotenotomy. - In: Life, ISSN 2075-1729, Bd. 12 (2022), 3, 332, S. 1-13
Biomechanical and biochemical changes in the muscle soleus of rats during imitation of hind limbs unuse were studied in the model of the Achilles tendon rupture (Achillotenotomy). Oral administration of water-soluble C60 fullerene at a dose of 1 mg/kg was used as a therapeutic agent throughout the experiment. Changes in the force of contraction and the integrated power of the muscle, the time to reach the maximum force response, the mechanics of fatigue processes development, in particular, the transition from dentate to smooth tetanus, as well as the levels of pro- and antioxidant balance in the blood of rats on days 15, 30 and 45 after injury were described. The obtained results indicate a promising prospect for C60 fullerene use as a powerful antioxidant for reducing and correcting pathological conditions of the muscular system arising from skeletal muscle atrophy.
https://doi.org/10.3390/life12030332
The effect of DC voltage pre-stress on breakdown voltage of air under composite DC & LI voltage and test circuit: design and application. - In: Energies, ISSN 1996-1073, Bd. 15 (2022), 4, 1353, S. 1-23
The use of HVDC systems is increasing in number due to technological innovations, increasing power capacity and increasing customer demand. The characteristics of insulation systems under composite DC and LI voltage must be examined and clarified. In this study, firstly, experimental circuits were designed to generate and measure composite DC and LI high voltage using a simulation program. The coupling elements used were chosen according to simulation results. Afterward, experimental circuits were established in the laboratory according to the simulation results of the designed experimental circuit. Then, breakdown voltages under composite DC and LI voltage for less uniform and non-uniform electric fields were measured with four different electrode systems for positive and negative DC voltage pre-stresses with different amplitudes. The 50% breakdown voltage was calculated using the least-squares method. Finally, 3D models were created for the electrode systems used in the experiments using the finite element method. The efficiency factors of electrode systems calculated with the FEM results were correlated with the experimental breakdown voltage results. Thus, the breakdown behavior of air under bipolar and unipolar composite voltages (CV) was investigated. In conclusion, the experimental results showed that very fast polarity change in bipolar CV causes higher electrical stress compared to unipolar CV.
https://doi.org/10.3390/en15041353