Quadrupeds and hexapods are known by their ability to adapt their locomotive patterns to their functions in the environment. Computational modeling of animal movement can help to better understand the emergence of locomotive patterns and their body dynamics. Although considerable progress has been made in this subject in recent years, the strengths and limitations of kinematic simulations at the scale of small moving animals are not well understood. In response to this, this work evaluated the effects of modeling uncertainties on kinematic simulations at small scale. In order to do so, a multibody model of a ant was developed. The model was built from 3D scans coming from X-ray micro-computed tomography. Joint geometrical parameters were estimated from the articular surfaces of the exoskeleton. Kinematic data of a free walking ant was acquired using high-speed synchronized video cameras. Spatial coordinates of 49 virtual markers were used to run inverse kinematics simulations using the OpenSim software. The sensitivity of the model's predictions to joint geometrical parameters and marker position uncertainties was evaluated by means of two Monte Carlo simulations. The developed model was four times more sensitive to perturbations on marker position than those of the joint geometrical parameters. These results are of interest for locomotion studies of small quadrupeds, octopods, and other multi-legged animals.
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http://dx.doi.org/10.3389/fbioe.2022.767914 | DOI Listing |
Phys Rev Lett
December 2024
CERN, Geneva, Switzerland.
High-energy nuclear collisions create a quark-gluon plasma, whose initial condition and subsequent expansion vary from event to event, impacting the distribution of the eventwise average transverse momentum [P([p_{T}])]. Disentangling the contributions from fluctuations in the nuclear overlap size (geometrical component) and other sources at a fixed size (intrinsic component) remains a challenge. This problem is addressed by measuring the mean, variance, and skewness of P([p_{T}]) in ^{208}Pb+^{208}Pb and ^{129}Xe+^{129}Xe collisions at sqrt[s_{NN}]=5.
View Article and Find Full Text PDFHeliyon
November 2024
Department of Industrial Engineering and Automotive, Nebrija University, Santa Cruz de Marcendo 27, 28040, Madrid, Spain.
The use of numerical methods for structural analysis has been increasingly integrated within the design process in different engineering fields over the last decades, inasmuch as the capacity of the computing resources have growth. This gave rise to calculation techniques based on virtual models such as the finite element method, which is nowadays a reference method for evaluation of complex tubular structures with vast application in the industry. For such type of structures, modeling approaches based on beam type elements are usually employed since they provide simplicity and low computational costs.
View Article and Find Full Text PDFRev Sci Instrum
January 2025
School of Electronic Engineering, Heilongjiang University, Harbin, HeiLongJiang 150080, China.
Gluing is a critical step in aircraft sealing assembly, with glue profile inspection serving as the final quality assurance measure to ensure consistency and accuracy of the sealant coating, allowing timely detection and correction of defects to maintain assembly integrity and safety. Currently, existing glue inspection systems are limited to basic inspection capabilities, lack result digitization, and exhibit low efficiency. This paper proposes a 3D inspection technology for sealant coating quality based on line-structured light, enabling automated and high-precision inspection of sealant thickness, sealant width, positional accuracy, and overlap joint sealant contour through geometric computation.
View Article and Find Full Text PDFSci Rep
December 2024
College of Aerospace Engineering, Shenyang Aerospace University, Shenyang, 110136, China.
This paper had conducted tensile shear tests on single-lap joints (SLJs)bonded structures of carbon fiber reinforced resin matrix (CFRP) composite laminates with different overlap lengths, overlap widths, overlap model, adherend material, and adhesive layer thicknesses under two environments: room temperature dry state (RTD) and elevated temperature wet state (ETW). The failure modes were observed, and load-displacement curves were obtained. The microscopic morphology of the fracture surface was observed by scanning electron microscope (SEM).
View Article and Find Full Text PDFNat Commun
December 2024
Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD, USA.
Non-Hermitian models describe the physics of ubiquitous open systems with gain and loss. One intriguing aspect of non-Hermitian models is their inherent topology that can produce intriguing boundary phenomena like resilient higher-order topological insulators (HOTIs) and non-Hermitian skin effects (NHSE). Recently, time-multiplexed lattices in synthetic dimensions have emerged as a versatile platform for the investigation of these effects free of geometric restrictions.
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