Aeroelastic analysis of an aircraft with a high aspect ratio wing for medium altitude and long endurance capability was attempted in this paper. In order to achieve such an objective, various ...structural models were adopted. The traditional approach has been based on a one-dimensional Euler-Bernoulli beam model. The structural analysis results of the present beam model were compared with those by the three-dimensional NASTRAN finite element model. In it, a taper ratio of 0.5 was applied; it was comprised of 21 ribs and 3 spars, and included two control surfaces. The relevant unsteady aerodynamic forces were obtained by using ZAERO, which is based on the doublet lattice method that considers flow compressibility. To obtain the unsteady aerodynamic force, the structural mode shapes and natural frequencies were transferred to ZAERO. Two types of unsteady aerodynamic forces were considered. The first was the unsteady aerodynamic forces which were based on the one-dimensional beam shape; the other was based on the three-dimensional FEM model shape. These two types of aerodynamic forces were compared, and applied to the foregoing flutter analysis. The ultimate goal of the present research is to analyze the possible interaction between the rigid-body degrees of freedom and the aeroelastic modes. This will be achieved after the development of a reliable nonlinear beam formulation that would validate the current results as well as enable a thorough investigation of the nonlinearity. Moreover, such analysis will allow for an examination of the above-mentioned interaction between the flight dynamics and aeroelastic modes with the inclusion of the rigid body degrees of freedom.
Forest bathing is suggested to have beneficial effects on various aspects of human health. Terpenes, isoprene based-phytochemicals emitted from trees, are largely responsible for these beneficial ...effects of forest bathing. Although the therapeutic effects of terpenes on various diseases have been revealed, their effects on neuronal health have not yet been studied in detail. Here, we screened 16 terpenes that are the main components of Korean forests using Drosophila Alzheimer’s disease (AD) models to identify which terpenes have neuroprotective effects. Six out of the 16 terpenes, ρ-cymene, limonene (+), limonene (−), linalool, α-pinene (+), and β-pinene (−), partially suppressed the beta amyloid 42 (Aβ42)-induced rough eye phenotype when fed to Aβ42-expressing flies. Among them, limonene (+) restored the decreased survival of flies expressing Aβ42 in neurons during development. Limonene (+) treatment did not affect Aβ42 accumulation and aggregation, but did cause to decrease cell death, reactive oxygen species levels, extracellular signal-regulated kinase phosphorylation, and inflammation in the brains or the eye imaginal discs of Aβ42-expressing flies. This neuroprotective effect of limonene (+) was not associated with autophagic activity. Our results suggest that limonene (+) has a neuroprotective function against the neurotoxicity of Aβ42 and, thus, is a possible therapeutic reagent for AD.
The presented paper introduces a novel path planning algorithm designed for generating low-cost trajectories that fulfill mission requirements expressed in Linear Temporal Logic (LTL). The proposed ...algorithm is particularly effective in environments where cost functions encompass the entire configuration space. A core contribution of this paper is the presentation of a refined approach to sampling-based path planning algorithms that aligns with the specified mission objectives. This enhancement is achieved through a multi-layered framework approach, enabling a simplified discrete abstraction without relying on mesh decomposition. This abstraction is especially beneficial in complex or high-dimensional environments where mesh decomposition is challenging. The discrete abstraction effectively guides the sampling process, influencing the selection of vertices for extension and target points for steering in each iteration. To further improve efficiency, the algorithm incorporates a deep learning-based extension, utilizing training data to accurately model the optimal trajectory distribution between two points. The effectiveness of the proposed method is demonstrated through simulated tests, which highlight its ability to identify low-cost trajectories that meet specific mission criteria. Comparative analyses also confirm the superiority of the proposed method compared to existing methods.
The bifunctionality of chromism-integrated sensors and devices has been highlighted because of their reversibility, fast response, and visual indication. For example, one of the representative ...chromism electrochromic materials exhibits optical modulation under ion insertion/extraction by applying a potential. This operation mechanism can be integrated with various sensors (pressure, strain, biomolecules, gas, etc.) and devices (energy conversion/storage systems) as visual indicators for user-friendly operation. In this review, recent advances in the field of chromism-integrated systems for visual indicators are categorized for various chromism-integrated sensors and devices. This review can provide insights for researchers working on chromism, sensors, or devices. The integrated chromic devices are evaluated in terms of coloration-bleach operation, cycling stability, and coloration efficiency. In addition, the existing challenges and prospects for chromism-integrated sensors and devices are summarized for further research.
This study performed computational fluid dynamics (CFD) simulation to investigate the flow patterns of molten pool during welding with a transient heat transfer. The influence of gravity changed the ...flow patterns of the molten pool, which determined the molten pool length and cooling time from 800℃ to 500℃(t
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) under the same heat input. In the flat position, the upward flow caused by arc forces and the inward flow generated by Marangoni convection resulted in a conflict between flows, and a molten pool length of 12.1 mm. In the overhead position, the volume of the molten pool was continuously drawn by gravity, eliminating the conflict between the inward and the upward flow. Therefore, convective heat transfer accelerated toward the edge of the molten pool, leading to an increased molten pool length (15 mm). In the vertical downward position, gravity pushed the molten pool toward the welding direction. The resultant flow pattern resulted in a rapid cooling rate and reduced the upward flow of the molten pool, leading to a short molten pool length (8.8 mm). The t
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obtained from the CFD were coupled with thermodynamic simulations to predict the microstructures of the coarse-grain heat-affected zone.
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