Search Results (470)

Piezoelectric energy harvesting technology has received great research interest in recent years. To harvest energy from rotational motion, this work proposes a cantilevered piezoelectric energy harvester based on an adjustable rigid parallel connection. The baffle was designed as a carrier for the rigid connection of the piezoelectric beams A, B and C. The theoretical model of the device was established, and equations for voltage and power were derived. The calculated intrinsic frequencies of the piezoelectric beams are consistent with the experimental results. The baffle size, the distance from the baffle to the free end, and the number of rotor bumps were used as variables in the experiments. The experimental results show that the proposed piezoelectric energy harvester can harvest energy across multiple frequency bands. The maximum average power of the proposed piezoelectric energy harvester is 110.49 mW at a load resistance of 10 kΩ and a rotational speed of 240 r/min. The maximum average power of the harvester is 36.44 mW at a load resistance of 10 kΩ and a rotational speed of 60 r/min. The rigid parallel connection not only broadens the energy harvesting bandwidth but also enhances the output performance of the harvester. Full article

Bandlimited functions are functions whose Fourier transform is confined to a finite band of frequencies. We generalize this concept to representations other than the Fourier transform and show that this leads to a variety of inequalities in arbitrary representations. Several special cases are considered, including frequency, dilation, and the chirplet transform, among others. Examples are given to illustrate each result. We apply the results to quantum mechanical wave functions and probability distributions. For bounded momentum wave functions, we obtain explicit bounds on the position wave function and its derivatives, as well as bounds on the position probability distribution. We also consider the dual problem in which the position wave function is bounded, as in the case of a particle in a box with an arbitrary wave function, and obtain bounds on the corresponding momentum wave function and momentum probability distribution. The case of wave functions that are sums of a finite number of energy eigenfunctions is also developed, and bounds on the associated probability distributions are obtained. A number of specific examples are considered, including a truncated Gaussian wave function and a quantum bump wave function. Full article

The protein kinase N family belongs to the AGC kinase group and contains three isozymes: PKN1, PKN2, and PKN3. Catalytic domains of PKNs share high sequence similarity, yet the proteins differ in tissue distribution, functions, and involvement in pathological processes. In particular, PKN3 has been implicated in tumor growth and metastatic progression, highlighting the need for isozyme-selective inhibitors as both research tools and therapeutic leads. Here, we report the rational design of selective PKN3 inhibitors based on distinctive structural features of this kinase. Two strategies were applied. First, the smaller threonine gatekeeper residue unique to PKN3 within the AGC group was exploited by derivatization of N-(2-aminoethyl)isoquinoline-5-sulfonamide (H-9) at position C8. Among the resulting compounds, a phenylamino-substituted derivative displayed the highest affinity, with a dissociation constant (K_D) of 23 nM and more than 1000-fold selectivity over protein kinase A. Second, bisubstrate-analog design was employed to enhance binding to basophilic AGC kinases through covalent attachment of a (d-Arg)₃-containing chain to H-9 derivatives. This approach yielded ARC-2603, which bound PKN3 with a K_D value of 0.2 nM and showed 5500-fold selectivity over PKAcα. The selectivity of ARC-2603 was further evaluated in a commercial panel of 397 protein kinases, which supported its utility as a highly selective PKN3 inhibitor. Full article

Aiming at the challenge of simultaneously optimizing ride comfort and wheel grounding performance for mining dump trucks under severe road conditions, this paper proposes a hydro-pneumatic suspension parameter design method based on an improved multi-objective particle swarm optimization (IMOPSO) algorithm. First, a dynamic model of the hydro-pneumatic suspension is established, incorporating the coupled nonlinear characteristics of the valve system and the gas chamber. The accuracy of the model is verified through bench tests. Subsequently, the influence of key parameters, including the damping orifice diameter, check valve seat hole diameter, and initial gas charging height, on the vertical dynamic performance of the vehicle, is systematically analyzed. On this basis, a multi-objective optimization model is constructed with the objective of minimizing the root mean square (RMS) values of both the sprung mass acceleration and the dynamic tire load. To enhance the global search capability and convergence performance of the MOPSO algorithm, adaptive inertia weighting, dynamic flight parameter update, and an enhanced mutation strategy are introduced. Simulation results demonstrate that the optimized suspension achieves significant improvements under various road conditions. On class-C roads, the RMS values of the sprung mass acceleration (SMA) and the dynamic tire load (DTL) are reduced by 37.6% and 15.8%, respectively, while the suspension rattle space (SRS) decreases by 10.2%. Under transient bump roads, the peak-to-peak (Pk-Pk) values of the same two indicators drop by 38.9% and 44.9%, respectively. Furthermore, compared to the NSGA-II algorithm, the proposed method demonstrates superior performance in terms of convergence stability and overall performance balance. These results indicate that the proposed design effectively balances ride comfort, wheel grounding performance, and driving safety. This study provides a theoretical foundation and an engineering-feasible method for the performance balancing and parameter co-design of suspension systems in heavy-duty engineering vehicles. Full article

As computational fluid dynamics (CFD) has become more mainstream in production engineering workflows, new demands have been introduced that require high-quality meshes to accurately capture the complex geometries. This evolution has created the need for mesh generation frameworks that help engineers design optimized meshing structures for each new geometry. However, many simulation workflows rely on the experience and intuition of senior engineers rather than systematic frameworks. In this paper, a novel technique for determining mesh convergence is created using machine learning (ML). This method seeks to provide process engineers with a visual feedback mechanism of flow regions that require mesh refinement. The work was accomplished by creating three grid sensitivity studies on various geometries: zero-pressure-gradient flat plate, bump in channel, and axisymmetric free jet. The cases were then simulated using the Reynolds Averaged Navier-Stokes (RANS) models in OpenFOAM (v2306) and had the ML method applied post-hoc using Python (v3.12.6). To apply the method to each case, the flow field was regionalized and clustered using an unsupervised ML model. The ML clustering results were then converted into a similarity score, which compares two grid levels to inform the user whether the region of the flow had converged. To prove this framework, the similarity scores were compared to flow field probes used to determine mesh convergence at key points in the flow. The method was found to be in agreement with the flow field probes on the level of mesh refinement that created convergence. The approach was also seen to provide refinement region recommendations in regions of the flow that align with human intuition of the physics of the flow. Full article

Bump feeding is a nutritional management strategy in swine production that involves increasing feed allowance and/or dietary nutrient density during the final weeks of gestation, usually from day 90 to farrowing, to support rapid fetal growth and prepare sows for lactation. This strategy is widely applied to improve piglet birth weight, neonatal viability, and subsequent reproductive performance. This review synthesizes current evidence on the effects of increased maternal feed intake during late gestation on sow body condition and feeding-related behavioral responses, and farrowing outcomes. Available studies suggest that increasing feed allowance during late gestation can influence litter characteristics, piglet survival at birth, and sow energy reserves, as reflected by changes in backfat thickness (BFT) and body condition score (BCS). The nutritional composition of bump-feeding diets, including dietary energy and amino acid balance, is critically evaluated in relation to pregnancy maintenance, farrowing duration, and early lactation performance. In addition, the roles of parity and feeding behavior during late gestation are examined, with particular emphasis on their associations with sow activity patterns, restlessness around parturition, and farrowing efficiency. Despite these reported effects, findings across studies remain inconsistent, particularly regarding the balance between improved reproductive outcomes and the risk of excessive fat deposition in sows. This review highlights key knowledge gaps and underscores the need for optimized, parity-specific bump-feeding strategies that integrate nutritional management with feeding behavior to enhance farrowing performance, piglet survival, sow welfare, and economic sustainability in modern pig production. Full article

The gravitational wave event GW190521 seems to be the only BH merger event possibly correlated with an electromagnetic counterpart, which appeared about 34 days after the GW event. This work aims to confirm that the electromagnetic bump towards the Active Galactic Nucleus (AGN) J1249+3449 can be explained within the framework of the gravitational microlensing phenomenon. In particular, considering the data of the Zwicky Transient Facility (ZTF), what emerges from a detailed analysis of the observed light curve using three fitting models (Point Source Point Lens, Finite Source Point Lens, Uniform Source Binary Lens) is that the optical bump can be explained as a microlensing event caused by a lens with mass $\sim$0.1 $M_{\odot }$, lying in the host galaxy of the AGN in question. Full article

This paper presents a virtual reference-based preview semi-active suspension system using a Magneto-Rheological (MR) damper to improve ride comfort when traversing bumps. The algorithm is designed to track the virtual reference profile of the vehicle’s corner by introducing a Model Predictive Control (MPC) method while considering the passivity of the MR damper. The proposed MPC is formulated to rely solely on estimable variables from an Inertial Measurement Unit (IMU) and vertical accelerometer. To support implementation on an Electronic Control Unit (ECU), the suspension state estimator employs a simple band-limited filtering structure. The proposed method is evaluated in simulation and achieves performance comparable to a controller that has accurate prior knowledge of the road profile. In addition, simulation results demonstrate that the proposed approach exhibits low sensitivity to sensor noise and bump perception uncertainty, making it well suited for real-world vehicle applications. Full article

Transonic shock buffet is a complex flow phenomenon characterized by self-sustained shock oscillations, which severely limits the flight envelope of modern civil aircraft. While Shock Control Bumps (SCBs) have been widely studied for drag reduction, their potential for delaying the buffet boundary on swept wings has yet to be fully explored. This study employs numerical analysis to investigate the efficacy of three-dimensional (3D) contour SCBs in delaying the buffet boundary of the NASA Common Research Model (CRM) wing. The buffet boundary is identified using both the lift-curve slope change and trailing-edge pressure divergence criteria. The results reveal that 3D SCBs generate streamwise vortices that energize the boundary layer, thereby not only weakening local shock strength but, more critically, suppressing the spanwise expansion of shock-induced separation. Collectively, the reduction in shock strength and the containment of spanwise separation delay the buffet boundary, thereby improving the aerodynamic efficiency of the wing. Two configurations, designed at different lift conditions (SCB-L at $C_L=0.460$ and SCB-H at $C_L=0.507$), demonstrate a trade-off between buffet delay and off-design drag reduction. The SCB-H configuration achieves a buffet boundary lift coefficient improvement of 6.3% but exhibits limited drag reduction at lower angles of attack, whereas the SCB-L offers a balanced improvement of 4.0%, with a broader effective drag-reduction range. These results demonstrate that effective suppression of spanwise flow is key to delaying swept-wing buffet and establish a solid reference framework for the buffet-oriented design of SCBs. Full article

Rocker–bogie suspension systems have been extensively employed in planetary exploration rovers due to their ability to traverse highly irregular terrains while maintaining ground contact. Traditionally, their mechanical behavior has been analyzed using quasi-static models, given the low operational speeds typical of space missions. However, similar configurations are now being proposed for terrestrial applications in agriculture, defense, and logistics, where higher traversal speeds and more varied terrain conditions require a deeper understanding of the system’s dynamic response. This study analyzes some aspects of the kinematic and dynamic behavior of a rover with rocker–bogie suspension while traversing an obstacle with a harmonic profile. Both quasi-static and dynamic simulations are conducted, focusing on the time-varying contact forces at the wheels. Key findings include identifying the rate at which load reduction at which the load on one wheel becomes zero and the wheel tends to lift off the ground. These threshold speeds are mapped as a function of height and wavelength of the bump, providing design insights for applications requiring higher traversal speeds on uneven terrain. The analysis may also prove valuable for rovers equipped with visual sensor systems capable of mapping their surroundings and identifying obstacles, to determine whether they can be traversed and, if so, at what maximum speed. An experimental investigation was conducted with a small-scale rover to verify the theoretical results, for which the threshold speed was found to be 0.3 m/s, calculated for h = 16 mm and λ = 80 mm. Full article

Background/Objectives: This study aimed to compare two surgical techniques for Osia^® system implantation performed at two European clinical centers: Poznań (Poland) and Freiburg (Germany). Methods: The study included 83 patients who underwent Osia^® OSI200 and OSI300 implantation (89 implants). The analysis focused on surgical technique, postoperative healing, and long-term skin integrity and aesthetic outcomes. Results: The centers differed in their surgical approaches, particularly regarding skin incision design and bone preparation. Most patients experienced no complications. Implant explantation was required in two cases, and one patient with recurrent seroma underwent revision surgery. Both centers achieved excellent postoperative skin integrity, with minimal scar visibility in most patients. Patients treated in Freiburg showed significantly better outcomes in terms of retroauricular bump visibility or palpability (p < 0.05) and postoperative pain (p < 0.05). Conversely, patients operated on in Poznań reported numbness less frequently (p < 0.05). Conclusions: Osia^® system implantation is a safe and well-tolerated procedure, with postoperative complications occurring in only a small proportion of cases. The Freiburg technique appears to reduce visibility and palpability of retroauricular bump and postoperative pain, but may slightly increase the risk of numbness and, in some cases, lead to a more visible scar compared to the Poznań approach. Optimal outcomes may be achieved by combining elements of both surgical techniques. Full article

The silver carp (Hypophthalmichthys molitrix) is a filter-feeding fish species, characterized by significant morphological transformations in its filter-feeding apparatus, particularly the gill rakers, which are closely associated with dietary changes throughout its development. Despite the importance of these morphological innovations, the molecular mechanisms driving these changes remain largely unexplored. To investigate this, we employed an integrative approach combining scanning electron microscopy (SEM) and comparative transcriptomics to examine the gill rakers at five critical developmental stages (6, 15, 30, 45, and 60 days post-hatching, dph). SEM analysis revealed a structural evolution from sparse, bump-like protrusions to a dense, interlocking mesh. Simultaneously, transcriptomic analysis identified 10,184 differentially expressed genes (DEGs), which showed significant enrichment in pathways such as Focal Adhesion, ECM-Receptor Interaction, and the PI3K-Akt Signaling Pathway. Gene Set Enrichment Analysis (GSEA) indicated a coordinated upregulation of collagen and integrin gene families during the early developmental transition (6 vs. 15 dph), highlighting their crucial role in the formation of the sieve structure. This study reveals the molecular mechanisms of gill raker development in silver carp, providing initial insights into genetic regulation of morphology for ecological adaptation. The findings connect developmental biology, evolutionary biology, and ecology. Full article

Passive flow control methods are widely used to reduce drag in wall-bounded flows. A recent numerical study on separating turbulent flows over a bump covered with shark denticles revealed the formation of a reverse pore flow (RPF) beneath the denticle crowns under an adverse pressure gradient (APG). This RPF generates an upstream thrust, leading to drag reduction. Motivated by these findings, the present study investigates a bio-inspired Anisotropic Permeable Propulsive Substrate (APPS) that incorporates key geometric features of the shark denticles, enabling thrust generation by the RPF. The designed APPS is evaluated through both direct numerical simulations of turbulent channel flows at $R{e}_{\tau }$ = 1500 and experiments using 3D-printed structures in a turbulent boundary layer over a flat-plate model subjected to APG and flow separation (at $R{e}_{\theta }$ = 800). Both approaches demonstrate that the APPS successfully reproduces the RPF-induced thrust mechanism of shark denticles. The results further reveal the dependence of the pore flow on pressure gradient and substrate geometry. This work highlights two features of a thrust-generating APPS: a top surface that shields the porous media from the overlying flow while enabling vertical mass exchange, and a bottom region with dominant wall-parallel permeability, which guides the pore flow in the streamwise direction to generate the thrust. Full article

Advanced driver-assistance and autonomous systems require perception that is both robust and affordable. Monocular cameras are promising due to their ubiquity and low cost, yet detecting abrupt road surface irregularities such as curbs and bumps remains challenging. These sudden road gradient changes are often only a few centimeters high, making them difficult to detect and resolve from a single moving camera. We hypothesize that stable image-based homography, derived from robust geometric correspondences, is a viable method for predicting sudden road surface gradient changes. To this end, we propose a monocular, geometry-driven pipeline that combines transformer-based feature matching, homography decomposition, temporal filtering, and late-stage IMU fusion. In addition, we introduce a dedicated dataset with synchronized camera and ground-truth measurements for reproducible evaluation under diverse urban conditions. We conduct a targeted feasibility study on six scenarios specifically recorded for small, safety-relevant discontinuities (four curb approaches, two speed bumps). Homography-based cues provide reliable early signatures for curbs (3/4 curb sequences detected at a 5 cm threshold). These results establish feasibility for monocular, geometric curb detection and motivate larger-scale validation. The code and the collected data will be made publicly available. Full article

This paper presents a method to design a preview controller with virtual disturbance and an active suspension system for ride comfort improvement and motion sickness mitigation. Quarter-car and half-car models are selected as the vehicle model. With those models, an LQ optimal preview controller is designed in the discrete-time domain. In the controller, feedback controllers are designed with LQ static output feedback (SOF) control. In real driving environments, it is hard to exactly measure a bump profile, which causes performance deterioration. To cope with difficulties and uncertainties in measuring a real bump, a virtual disturbance is used instead of a real bump. In the LQ optimal preview controller, the virtual disturbance, used for the feedforward control, is optimized with a simulation-based optimization method. To show the effectiveness of the proposed method, a simulation is performed on a vehicle simulation package. The simulation results show that the LQ SOF controller decreases the vertical acceleration and pitch rate of the sprung mass by 28% and 66%, respectively, whereas the preview controllers with the optimized virtual disturbance yield reductions of 41% and 84%, respectively. Those results demonstrate that the proposed preview controller with the optimized virtual disturbance can effectively enhance ride comfort and mitigate motion sickness. Full article