Molecular structure, vibrational spectra, electronic properties, and receptor bindingmechanism Salbutamol, a short-acting β₂-adrenergic agonist used in asthma therapy,were studied using density functional theory (DFT) and molecular docking methods. The molecular geometry was optimized at the DFT/B3LYP/3-21G level of theory. Thecalculated rotational constants are A = 0.917 GHz, B = 0.209 GHz, and C = 0.182 GHzprovide insights into the molecular moments of inertia. The HOMO-LUMO energy gapwas found to be 5.14 eV in the gas phase, decreasing in polar solvents, which indicated enhanced electronic polarization. Time-dependent DFT (TD-DFT) simulations revealedstrong π→π* electronic transitions in the near-ultraviolet region. Molecular docking ofSalbutamol into thebinding site of the human β₂-adrenergic receptor (PDB ID: 3NY8)yielded a binding affinity of -7.545 kcal/mol. The docking pose shows that Salbutamolforms hydrogen bonds with ASP113 and ASN312, and engages in hydrophobic contactswith VAL114, VAL117, and PHE290. These structural and electronic insights rationalizethe known biological activity of Salbutamol and may guide the future design of improved β₂-agonist drugs.

Abstract We investigate, for the first time, universal relations for anisotropic dark energy stars. The stars are modeled with the modified Chaplygin equation of state and the Bowers–Liang prescription for anisotropy, and their global properties and f -mode frequencies are computed using the modified relativistic Hartle–Thorne slow rotation and Cowling approximations. We find that relations among moment of inertia, tidal deformability, quadrupole moment and f -mode frequency exhibit universality, with deviations limited to $$\sim 1{-}10\%$$ ∼ 1 - 10 % , in close agreement with other compact star models. Using tidal deformability constraints from GW170817 and GW190814, we obtain astrophysical limits on canonical properties of dark energy stars. For positive anisotropy strength, the radius of a $$1.4M_\odot $$ 1.4 M ⊙ star is constrained to $$R_{1.4}=8.93^{1.88}_{1.40}$$ R 1.4 = 8 . 93 1.40 1.88 km (GW170817) and $$10.92^{+0.71}_{-0.54}$$ 10 . 92 - 0.54 + 0.71 km (GW190814), consistent with observational bounds. The corresponding f -mode frequencies are constrained to $$3.257^{+0.450}_{-0.537}$$ 3 . 257 - 0.537 + 0.450 kHz and $$2.692^{+0.137}_{-0.157}$$ 2 . 692 - 0.157 + 0.137 kHz. Further, applying Pearson correlation analysis for the first time to anisotropic compact stars, we obtained the coefficients between various stellar attributes of dark energy stars and we show that the Chaplygin parameter B correlates strongly with the f -mode frequency, with positive anisotropy strengthening while negative anisotropy weakening the correlation strength. These results establish that universal relations extend to anisotropic dark energy stars and can be directly tested with present and future gravitational-wave observations

This study introduces a simplified finite element modeling (SFEM) approach for high-rise structures, reducing computational time while accurately capturing their dynamic response. In the proposed model, the moment of inertia of vertical load-bearing elements is concentrated at selected nodes, while the lateral stiffness between stories is represented by fictitious beams. A single-mode calibration is first applied to match the fundamental period obtained from structural health monitoring (SHM) data, demonstrating that the simplified model can capture the dominant structural behavior with minimal data. Subsequently, a deep learning-based inverse design method is introduced to calibrate story-wise fictitious beam stiffness using multiple modal periods, enhancing the model's accuracy across varying floor stiffness profiles and torsional effects. Calibration requires only the first three modal frequencies and data from two sensors located on a single floor in regular-plan structures. The approach is validated using real data from the 7-story Van Nuys building and five numerical high-rise frame-core tube FEM case studies. The calibrated model accurately predicts both translational and torsional responses. High correlation metrics confirm its efficiency, demonstrating that the proposed framework is practical, data-efficient, and suitable for structural health monitoring and rapid post-earthquake assessments.

This paper addresses the efficiency gap in compact, self-starting electric generators for autonomous devices, where mechanical and electrical losses degrade output and lifetime (problem and relevance). We study a pulse-controlled generator with a pendulum-inertial cone rotor and dual magnetic excitation—constant field for stabilization and alternating field for adaptive energy injection – targeted at maximizing conversion from mechanical oscillations to electrical power (methods). A time-domain model with realistic losses (bearing friction, coil resistance, current/voltage limits) was implemented in Python/NumPy and validated by numerical experiments over 0–10 s. Parameter sweeps covered moment of inertia, friction coefficient, load resistance, pulse amplitude and duration, number of turns, and magnetic flux; outputs included angular speed, induced EMF, current, and accumulated energy. Our key hypothesis is that combining inertial smoothing with sparse pulse actuation increases net energy and extends steady operation versus a permanent-magnet, no-pulse baseline. The simulations confirm this, attributing gains to reduced torque ripple, selective compensation of dissipation, and recovery through a self-charging loop (hypotheses and findings). Distinguishing features are the cone rotor acting as a pendulum stabilizer, dual-field control, and low-loss pulse start. Practical use is foreseen in energy-harvesting nodes and low-power drives where short start-up energy is available, mechanical losses are moderate, and load impedance can be matched. The results guide sizing and control co-design without serving as an introduction.

We theoretically investigate a binary Bose-Einstein condensate in which the majority component hosts a vortex necklace, whose vortex cores act as moving effective potential wells for the minority component. This configuration represents a tunable periodic landscape whose strength is controlled by the intercomponent interaction. As the coupling increases, the minority component undergoes a crossover from a delocalized, nearly perfect superfluid to an array of localized density peaks confined within the vortex cores. Using Gross-Pitaevskii simulations, we compute the moment of inertia of the minority component and show that its superfluid fraction is tightly bracketed by Leggett's bounds constructed from its density profile. Because these bounds depend solely on the spatial density distribution, they may be extracted directly from experimentally accessible measurements. Our results identify vortex necklaces as a controllable tool for tuning and probing superfluidity in two-component condensates and provide a natural framework for exploring superfluid behavior in dynamically evolving and disordered potentials.

Proximal-specific reduced mass of lower limbs in male endurance runners does not result in improved mechanical ease of leg swing in proportion to reduced mass.

Comparing Sliding vs. Rolling to Determine Moments of Inertia of 3D-Printed Cylinders

The observational efficiency of pulsars, defined as the ratio of the observationally derived isotropic-equivalent luminosity, 4π d_ obs ^2 F_ obs , where F_obs is the average pulsed energy flux of a pulsar and d_obs is its estimated distance, to its energy budget, shows a wide range of values. This dispersion is believed to be a combination of beaming effects, different geometries, and case-by-case variability of the emission mechanism efficiency, but it is not clear in what proportion. In this work we focused on the γ-ray range and analysed the four main ingredients that likely contribute to this dispersion: the geometrical term arising from the anisotropic emission (beaming), viewing and inclination angles, the uncertainty on the pulsar distance, the uncertainty on the moment of inertia, and the intrinsic efficiency of the mechanism producing the γ-ray emission. Estimating the expected ranges of the moment of inertia and the distance errors, and considering a geometrical and spectral model that we have recently used to fit the light curves and spectra of the entire γ-ray pulsar population, we estimate the a priori distribution of the first three ingredients in order to obtain the a posteriori distribution of the intrinsic efficiency of the mechanism. We found the latter to peak at ∼ 5-15 % (depending on the trial distribution) and to have a dispersion of around one order of magnitude. That is, we found the intrinsic efficiency of the mechanism to be the leading factor in the observed dispersion. In addition, we found little sensitivity of these results on different distributions of the estimated pulsar distance errors, and saw that the weak, alleged correlation with the spin-down power can only explain part of the observed dispersion. This methodology can be easily applied to other geometrical models of the emission, to test the sensitivity of these results on the beaming distribution.

ABSTRACT Finite element model updating (FEMU) is essential for improving the accuracy of structural simulations, particularly in seismic analysis of high‐rise buildings. This study focuses on updating the finite element model of a high‐rise structure based on seismic response data recorded during the M6.4 Yangbi earthquake in Dali, Yunnan Province, China, on May 21, 2021. A structural seismic response monitoring array was deployed in the building, capturing valuable data that reflects the building's dynamic characteristics under actual seismic loads. To enhance the accuracy of the model update, intelligent optimization algorithms were applied, including particle swarm optimization (PSO), ant colony optimization (ACO), fish swarm algorithm (FSA), and artificial bee colony (ABC). Additionally, a response surface model was constructed to reduce computational costs and improve efficiency. The study further explores the influence of key structural parameters—such as elastic modulus and moment of inertia—on model performance through sensitivity analysis and response surface modeling. The results demonstrate that the intelligent optimization algorithms successfully improved the accuracy of the finite element model, with average errors below 1.5% for all tested algorithms. Evolutionary algorithms, particularly PSO and ACO, showed superior performance in reducing discrepancies between simulated and observed data, enhancing the model's predictive capability. The findings underscore the significance of integrating seismic response data with intelligent optimization techniques for robust structural model updating, contributing to more reliable performance‐based earthquake engineering (PBEE) practices.

This study demonstrates an experimental approach for direct measurement of RC elastic modulus. This work considered the transformed moment of inertia as an input variable. The planned laboratory study involves subjecting reinforced concrete beams with varying reinforcement ratios from 0.43% to 1.77% and grades of concrete (M7.5, M10, M15, M20) to bending tests. Two equations for elastic modulus determination were developed based on beam theory. The first crack load and the corresponding deflection were measured from the load-deflection curve. The uncracked transformed moment of inertia (Iun,tr), cracking moment (Mcr), and deflection ( at first crack were computed. By substituting the Mcr, and Iun, tr into the deflection equation based on the test setup, the elastic modulus (E) of RC was determined. Results showed that as the concrete grade increases, so does its modulus of elasticity, and it demonstrated a direct correlation between the increase in concrete grade and its modulus of elasticity. It was also observed that as the percentage of reinforcement increases, the elastic modulus of RC increases due to increased flexural stiffness. The derived equations were able to accurately compute the elastic modulus capturing the composite behavior of concrete and reinforcement.

The trajectories and interaction forces of five bodies with equal masses are analytically described. The bodies follow a choreographic motion in a figure of eight, Gerono lemniscata periodic orbit without collisions. The forces are a linear combination of pairwise distances with either attractive or repulsive coefficients. The center of mass is fixed at the origin. The moment of inertia, as well as the kinetic and potential energies of the system, are constant. Notably, the angular momentum is zero just as in the Bernoulli Lemniscata parametrized by elliptic functions. The number of bodies in the choreography can be increased in a straightforward way. The orbit can be readily generalized to symmetric chains with an arbitrary number of loops.

This study investigates the dynamic behavior of an elastic joint manipulator system with stochastic noise and time delay. Firstly, considering the time delay caused by the difference in inertial moments between the lightweight link and the heavy rotator, as well as the noise in the system, a model of the manipulator system with delay and stochastic is constructed. Secondly, the time-delay differential equation is reduced to a finite-dimensional ordinary differential equation using the center manifold, and then the system’s generalized Ito equation is obtained using the stochastic averaging method. The stationary probability density dominated by the Fokker-Planck-Kolmogorov (FPK) equation is studied, followed by an investigation of the system’s stochastic bifurcation behavior. Finally, through numerical simulation, the extent to which time delay, stiffness, and damping affect the amplitude of the manipulators are studied.

A bstract We analyze various two-point correlation functions of fermionic bilinears in a rotating finite-size cylinder at finite temperatures, with a focus on susceptibility functions. Due to the noninvariance of radial translation, the susceptibility functions are constructed using the Dirac propagator in the Fourier-Bessel basis instead of the plane-wave basis. As a specific model to demonstrate the susceptibility functions in an interacting theory, we employ the two-flavor Nambu-Jona-Lasinio model. We show that the incompatibility between the mean-field analysis and the Fourier-Bessel basis is evaded under the local density approximation, and derive the resummation formulas of susceptibilities with the help of a Ward-Takahashi identity. The resulting formulation reveals the rotational effects on meson, baryon number, and topological susceptibilities, as well as the moment of inertia. Our results may serve a useful benchmark for future lattice QCD simulations in rotating frames.

This study uses a coupled lattice Boltzmann and discrete element method to perform interface-resolved simulations of turbulent channel flow laden with finite-size cylindrical particles. The aim is to investigate interactions between wall-bounded turbulence and non-spherical particles with sharp edges. The particle-to-fluid density ratio is unity and gravity is neglected. Comparative analyses are conducted among long (length-to-diameter aspect ratio 2), unit (1) and short ( $ 1/2 $ ) cylinders, along with spheres and literature data for spheroids. Results reveal both shared and distinct dynamic behaviours of cylinders and their effects on turbulence modulation. Notably, disk-like short cylinders can remain trapped near the wall due to their flat faces aligning closely with it – a behaviour unique to particles with sharp edges. Long and unit cylinders, as well as spheres, preferentially accumulate in high-speed streaks, while short cylinders cluster in low-speed streaks, demonstrating a strong aspect-ratio effect. Near the wall, long cylinders align their axis with the streamwise direction, while short cylinders orient perpendicular to the wall. Rotationally, long cylinders primarily spin, whereas short ones predominantly tumble. These trends arise from orientation preferences and differences in axial and spanwise moments of inertia. Cylindrical particles increase wall drag compared with the single-phase case, with short cylinders causing the greatest enhancement due to strong near-wall accumulation. Overall, the influence of aspect ratio on particle dynamics and turbulence modulation is more pronounced for cylindrical particles than for spheroidal ones.

In sustainable energy, fuel cells are seen as the most favorable energy source, given their ability to directly convert chemical energy into electrical energy and achieve elevated electrical efficiency. Also, as high-temperature fuel cells, solid oxide fuel cells are considered promising due to fuel flexibility, high efficiency, and low emissions. However, solid oxide fuel cells have the issue that if fuel utilization is very high, the stack may lead to polarization and pose a significant risk of fuel starvation. The cascade SOFC system can increase the fuel utilization rate of the entire system by placing two stacks with low fuel utilization rates in series. Through the previously developed steady-state cascade SOFC system model, the maximization of power generation efficiency, system design optimization, fuel regenerator, optimal operation, and control methods have been derived. To be utilized in distributed power applications that meet the power demand, dynamic analysis must be performed. So, The objective of the research is to develop a dynamic model of a cascade SOFC system. This study confirmed the dynamic characteristics of the cascade SOFC system when the power demand load profile is assumed to be ramp-up and ramp-down. As a result, when the power demand load profile changed, the under-shoot and over-shoot characteristics of the stack's power and voltage were confirmed. The dynamic characteristics were confirmed to be influenced by the time delay in achieving the target supply quantity due to moment of inertia and the impact of PI control in response to changes in the flow rates of the air supply blower, water supply pump, and fuel supply valve, resulting in temperature variations in the system.

Alzheimer's disease (AD) and osteoporosis frequently co-occur in the elderly; however, the pathophysiological link between these two diseases remains unclear. This study investigates skeletal alterations in a triple transgenic 3xTg-AD mouse model of AD (3xTg-AD), which harbors mutations in β-amyloid precursor protein (βAPPSwe), presenilin-1 (PS1M146V), and tauP301L, and recapitulates key aspects of AD pathology, including age-dependent β-amyloid plaque accumulation and cognitive decline. To assess early skeletal changes, we analyzed femurs and tibiae of 2-month-old male non-Tg and 3xTg-AD mice (n = 9/group) using micro-CT. Despite the absence of β-amyloid plaques at this stage, 3xTg-AD mice showed significant cortical bone loss, with reduced bone surface, periosteal and endosteal perimeters, total and cortical cross-sectional area, and polar moment of inertia. The 3-point-bending test confirmed compromised mechanical properties, including reduced maximum load-to-fracture and stiffness. Histological analyses highlighted an increased number of Empty Osteocyte Lacunae, reduced TRAP+ osteocytes, and an elevated number of osteoclasts; such evidence indicates impaired osteocyte function and increased bone resorption. These findings indicate that cortical bone loss and compromised mechanical properties occur before detectable neuropathological hallmarks in this AD model.

The geometrical view of the electron as a spinning bivector leads to the partitioning of the electron’s energy into internal and external. The reduced Compton wavelength, λ¯C, is taken as the radius of the inertial ring (a disc), while re characterizes the EM coupling scale. Within this picture, the fine-structure constant emerges as the structural ratio α=re/λ¯C. We make the partitioning explicit, derive simple ratios among moments of inertia and stored energies, and compare the Bivector Standard Model with the Standard model.

Abstract This study presents a unificative methodology for determining the latest dynamic parameters of tectonic plates, including moment of inertia, angular momentum, and kinetic energy, using data from continuous GNSS stations combined with information on crustal thickness and density from the CRUST1.0 model. The methodology treats the tectonic plate as a system of discrete volume cells, each with a defined mass and distance to the axis of rotation, which allows for accurate calculation of dynamic parameters. The approach has been tested on 7 large, 7 medium, and 3 microplates using data from 3169 GNSS stations for the period 2002–2021. The methodology provides an uncertainty of parameter estimation of less than 5.5 %, offering a new tool for detailed assessment of lithospheric dynamics and understanding the distribution of rotational energy in the Earth’s plates.

Abstract We investigate the properties of neutron stars within the framework of f(Q) gravity by incorporating rotational effects through a slowly rotating metric. We derive the modified TOV equations and calculate the angular velocity profiles and moments of inertia (MOI) for linear, quadratic, exponential, and logarithmic f(Q) models. Our results show that deviations in the MOI are more pronounced than those in the stellar mass profiles, suggesting that rotational observables are highly sensitive to geometric corrections. We also calculate a quasi-universal relation between the dimensionless MOI and compactness ($\bar{I}$-C). The linear and quadratic models are generally consistent with observational data from PSR J0737-3039A, although the deviations are small and difficult to distinguish from General Relativity due to inherent EoS variability. On other hand, the logarithmic and exponential models show larger deviations (over 20%), exceeding the EoS-induced uncertainty reported by Suleiman & Read (2024), highlighting the relation’s sensitivity to the f(Q) gravity model. These results indicate that f(Q) gravity could potentially be tested in the strong-field regime and point to a direction for future studies, such as investigating EoS-insensitive quasi-universal relations, like the $\bar{I}(\Lambda )$ relations, within the f(Q) framework. Such relations may provide a clearer pathway for exploring possible signatures in strong-field gravity when combined with more precise future observations.

Kinematic compatibility is crucial in wearable walking assistive devices. We aim to design wearable walking assistive devices with high degree of kinematic compatibility by focusing on tensegrity structure, regarded as the basis of the body structure. In this paper, we examined the factors required to design the tensegrity knee joint for wearable walking assistive devices. To support the mobility and stability of the knee joint, we designed a tensegrity joint with a mechanism to change its rigidity by changing the moment of inertia. Experimental results suggest that the mechanism can reduce the structure's rigidity by up to one-third.