Physics-informed Neural Network for Acoustic Resonance Analysis

This study proposes the physics-informed neural network (PINN) framework to solve the wave equation for acoustic resonance analysis. ResoNet, the analytical model proposed in this study, minimizes the loss function for periodic solutions, in addition to conventional PINN loss functions, thereby effectively using the function approximation capability of neural networks, while performing resonance analysis. Additionally, it can be easily applied to inverse problems. Herein, the resonance in a one-dimensional acoustic tube was analyzed. The effectiveness of the proposed method was validated through the forward and inverse analyses of the wave equation with energy-loss terms. In the forward analysis, the applicability of PINN to the resonance problem was evaluated by comparison with the finite-difference method. The inverse analysis, which included the identification of the energy loss term in the wave equation and design optimization of the acoustic tube, was performed with good accuracy.Comment: 11 pages, 14 figures. The following article has been submitted to the Journal of the Acoustical Society of America. After it is published, it will be found at https://pubs.aip.org/asa/jasa . v2: Corrected a typo in Eq. (22

Among-Clone Variations of Anatomical Characteristics and Wood Properties in Tectona Grandis Planted in Indonesia

Anatomical characteristics (vessel diameter [VD], fiber wall thickness [FWT], fiber diameter [FD], vessel element length [VEL], and fiber length [FL]) and wood properties (basic density [BD] and compressive strength parallel to grain [CS] in the green condition) were determined for 27 12-yr-old teak trees planted in Java Island, Indonesia. The mean values of VD, FWT, FD, VEL, FL, BD, and CS were 188 μm, 2.78 μm, 23.4 μm, 284 μm, 1.42 mm, 510 kg/m3, and 37.5 MPa, respectively. Significant differences in VEL, BD, and CS occurred among the nine clones. Moderate to high values of repeatability were obtained for FD, VEL, BD, and CS, indicating that these characteristics are genetically controlled. Radial variation of FL with respect to relative distance showed almost the same pattern for two different radial growth rates (faster and slower) at the same age, suggesting that xylem maturation in teak trees depends on cambial age rather than stem diameter

Technical Note: Solid Wood Properties of Eucalyptus Camaldulensis Planted for Pulpwood Production in Thailand

Solid wood properties of two Eucalyptus camaldulensis clones (clone A and clone B), derived from different pulp and paper companies and planted in Thailand for pulpwood production, were investigated to evaluate the possibility for lumber production. Clone A had significantly higher Young's modulus, greater density, and straighter grain compared with clone B. These results suggest that some clones may have more favorable properties for lumber production than others. Thus, wood properties should be included in clonal trials and early testing of this species

Wood Property Variation in Acacia Auriculiformis Growing in Bangladesh

This study examined the radial variations of wood properties in 11-yr-old Acacia auriculiformis grown in Bangladesh having diameters of 222 ± 38 mm. The basic density, fiber length, and fiber length increment increased up to about 80 mm radial distance from the pith and then were almost constant toward the bark. The compressive strength (CS) increased from the pith to 50 mm and then became nearly constant to the bark. Conversely, the specific compressive strength, the ratio of CS to air-dried density, was almost constant from pith to bark, indicating positive relationships. However, the air-dried density explained only 50% variation of the CS. On the basis of radial variation of basic density, the core wood and outer wood boundary can be delineated at 70 - 90 mm from the pith. Similarly, the fiber length and fiber length increment curves showed that this boundary could be marked at 60 - 90 mm from the pith. The selected wood properties except CS varied significantly among the trees, which indicated the potential of tree selection for wood quality improvement through tree breeding

Macrophage centripetal migration drives spontaneous healing process after spinal cord injury.

Traumatic spinal cord injury (SCI) brings numerous inflammatory cells, including macrophages, from the circulating blood to lesions, but pathophysiological impact resulting from spatiotemporal dynamics of macrophages is unknown. Here, we show that macrophages centripetally migrate toward the lesion epicenter after infiltrating into the wide range of spinal cord, depending on the gradient of chemoattractant C5a. However, macrophages lacking interferon regulatory factor 8 (IRF8) cannot migrate toward the epicenter and remain widely scattered in the injured cord with profound axonal loss and little remyelination, resulting in a poor functional outcome after SCI. Time-lapse imaging and P2X/YRs blockade revealed that macrophage migration via IRF8 was caused by purinergic receptors involved in the C5a-directed migration. Conversely, pharmacological promotion of IRF8 activation facilitated macrophage centripetal movement, thereby improving the SCI recovery. Our findings reveal the importance of macrophage centripetal migration via IRF8, providing a novel therapeutic target for central nervous system injury