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Frame analysis (FA) is known for its efficiency and low computer resource requirements. However, compared to finite element analysis (FEA), the applicability of FA for the seismic performance assessment of pile-supported wharves (PSWs) is limited, particularly in the ability to account for the kinematic force caused by ground displacement during an earthquake. This study aimed to develop a two-dimensional FA method for PSW seismic response analysis that considers a combination of inertial and kinematic forces. We performed FA and FEA and compared the results. First, we targeted the PSW model without considering the soil slope and discussed the spectral acceleration (SA) evaluation method for calculating inertial force. As a result, an equation for estimating a damping coefficient to evaluate the SA in accordance with the PSW width and natural period was proposed. Next, we targeted the PSW model by considering the soil slope and proposed a method to evaluate the kinematic force based on the amount of ground displacement and the soil spring characteristics. The results revealed that using the proposed method, FA, by considering kinematic and inertial forces, could reproduce the bending moments of the piles comparable to those calculated using FEA. Therefore, solely considering the inertial force for a PSW on a soil slope may cause the bending moment to be underestimated.

Numerical simulations of the geodynamo are becoming more realistic because of advances in computer technology. Here, the geodynamo model is investigated numerically at the extremely low Ekman and magnetic Prandtl numbers using the PARODY dynamo code. These parameters are more realistic than those used in previous numerical studies of the geodynamo. Our model is based on the Boussinesq approximation and the temperature gradient between upper and lower boundaries is a source of convection. This study attempts to answer the question how realistic the geodynamo models are. Numerical results show that our dynamo belongs to the strong-field dynamos. The generated magnetic field is dipolar and large-scale while convection is small-scale and sheet-like flows (plumes) are preferred to a columnar convection. Scales of magnetic and velocity fields are separated, which enables hydromagnetic dynamos to maintain the magnetic field at the low magnetic Prandtl numbers. The inner core rotation rate is lower than that in previous geodynamo models. On the other hand, dimensional magnitudes of velocity and magnetic fields and those of the magnetic and viscous dissipation are larger than those expected in the Earth’s core due to our parameter range chosen.

Hydromagnetic dynamos are numerically investigated at low Prandtl, Ekman and magnetic Prandtl numbers using the PARODY dynamo code. In all the investigated cases, the generated magnetic fields are dominantly-dipolar. Convection is small-scale and columnar, while the magnetic field maintains its large-scale structure. In this study the generated magnetic field never becomes weak in the polar regions, neither at large magnetic Prandtl numbers (when the magnetic diffusion is weak), nor at low magnetic Prandtl numbers (when the magnetic diffusion is strong), which is a completely different situation to that observed in previous studies. As magnetic fields never become weak in the polar regions, then the magnetic field is always regenerated in the tangent cylinder. At both values of the magnetic Prandtl number, strong polar magnetic upwellings and weaker equatorial upwellings are observed. An occurrence of polar magnetic upwellings is coupled with a regenaration of magnetic fields inside the tangent cylinder and then with a not weakened intensity of magnetic fields in the polar regions. These new results indicate that inertia and viscosity are probably negligible at low Ekman numbers.

A method is proposed for evaluating the dynamical friction of linear bearings, whose motion is not perfectly linear due to some play in its internal mechanism. In this method, the moving part of a linear bearing is made to move freely, and the force acting on the moving part is measured as the inertial force given by the product of its mass and the acceleration of its centre of gravity. To evaluate the acceleration of its centre of gravity, the acceleration of two different points on it is measured using a dual-axis optical interferometer.

Coronaviruses being capable of spreading through droplet contamination have raised significant concerns regarding high-capacity public rail transport, such as the metro. Within a rapidly moving railcar cabin, the internal airflow lags behind the bulkhead, generating internally induced airflow that accelerates droplet dispersion within a non-inertial reference system. This study investigates the impact of acceleration on the diffusion of cough droplets of varying sizes using computational fluid dynamics. The modified k–ε equation in ANSYS® Fluent was utilized to simulate droplet diffusion under different body orientations by adjusting the inertial force correction source term. Results indicate that droplets in the middle size range (50–175 μm) are primarily influenced by inertial forces, whereas smaller droplets (3.5–20 μm) are predominantly controlled by air drag forces. Regardless of facial orientation, the outlet of high-capacity public rail transport poses the highest risk of infection.

The particle dynamics equation’s formal logic is examined in the context of classical mechanics to investigate the nature of inertial forces. First, a fresh perspective on the dual dependence of the inertial reference frame and inertial force in Newtonian dynamics is presented. The causal relationship between the two sides of Newton’s second law is found to be asymmetrical and inconsistent. Secondly, a more general particle dynamics equation, applicable in any translational frame of reference without additional assumptions, is introduced. Essentially, Newton’s second law is only an extreme case of the newly generalized dynamics equation since in Newton’s second law an entire term of the forces acting on the reference object is omitted. The nature of inertial force is unveiled as the mass-ratio weighted real force acting on the reference object. This qualitative explanation is entirely naturalistic as the reference frame’s acceleration depends directly on the acceleration of its reference object(s), and the acceleration of every reference object depends directly on the forces acting on this reference object.

Purpose This study aims to describe the effects of capillary forces or action, viscosity, gravity and inertia via the computational fluid dynamics (CFD) analysis. The study also includes distribution of the binder droplet over the powder bed after interacting from different heights. Design/methodology/approach Additive manufacturing (AM) has revolutionized many industries. Binder jetting (BJT) is a powder-based AM method that enables the production of complex components for a wide range of applications. The pre-densification interaction of binder and powder is vital among various parameters that can affect the BJT performance. In this study, BJT process is studied for the binder interaction with the powder bed of SS316L. The effect of the droplet-powder distance is thoroughly analysed. Two different droplet heights are considered, namely, h1 (zero) and h2 (9.89 mm). Findings The capillary and inertial effects are predominant, as the distance affects these parameters significantly. The binder spreading and penetration depth onto the powder bed is influenced directly by the distance of the binder droplet. The former increases with an increase in latter. The binder distribution over the powder bed, whether uniform or not, is studied by the stream traces. The penetration depth of the binder was also observed along the cross-section of the powder bed through the same. Originality/value In this work, the authors have developed a more accurate representative discrete element method of the powder bed and CFD analysis of binder droplet spreading and penetration inside the powder bed using Flow-3D. Moreover, the importance of the splashing due to the binder’s droplet height is observed. If splashing occurs, it will produce distortion in the powder, resulting in a void in the final part.

Matter-wave interferometry offers insights into fundamental physics and provides a precise tool for sensing. Improving the sensitivity of such experiments requires increasing the time particles spend in the interferometer, which can lead to dephasing in the presence of velocity-dependent phase shifts such as those produced by the Earth's rotation. Here we present a technique to passively compensate for the Coriolis effect using gravity, without the need for any moving components. We demonstrate the technique with fullerenes in a long-baseline molecule interferometer by measuring the gravitational and Coriolis phase shifts and obtaining the maximum visibility one would expect in the absence of the Coriolis effect.

Continuous, label-free particle separation is essential for a broad range of biochemical and biomedical applications. Here, we present a microfluidic device that integrates inertial focusing and deterministic lateral displacement (DLD) within a compact channel architecture to achieve size-based particle sorting under laminar flow conditions. The design combines upstream curved channels for initial lateral positioning with downstream micropillar-embedded curved channels to enhance separation resolution. Theoretical analysis and numerical simulations were performed to optimize channel geometry and micropillar arrangement, predicting size-dependent lateral displacement driven by centrifugal forces and pillar-induced constraints. Experimental validation using glass beads of two distinct sizes (8 μm and 15 μm) demonstrated a separation efficiency exceeding 93% across a range of flow rates and particle concentrations. The device offers a simple, cost-effective, and scalable solution for passive particle sorting without external fields or labeling. The flexibility of the design configuration can be adapted for diverse applications, including extracellular vesicles, barcoded hydrogel particles, and engineered drug-delivery carriers.