Edge Boundary Research Articles

A unified dynamic model and vibration suppression for moving corrugated sandwich panels with general boundaries

The sandwich plate structures with corrugated cores are extensively utilized in engineering cases, such as the panels in railway vehicles, aerospace flight vehicles and so on. These sandwich plates in service can be simplified as the axially moving panel structures in the dynamic modeling. To research the dynamic behaviors of moving corrugated sandwich (CS) panels, an equivalent model is utilized. The energy method combined with penalty factor approach is applied to deduce the energy functions of the panel structure, and the corresponding formulations are further deduced based on the Hamilton's principle. Based on the proposed model, the examples with classical and elastic edge boundaries can be considered. Several computational examples are implemented to verify the present formulations, and satisfactory consistency can be observed. Meanwhile, impacts of several structural parameters on the dynamic and stability properties of the CS panel are investigated. To suppress the vibration of CS panels, the negative capacitance piezoelectric shunt damping circuit (PSDC) is further adopted. The impacts of the velocity parameter on the optimal values of the PSDC are discussed and calculated results demonstrate that dynamic responses of moving CS panels are satisfactorily attenuated by the proposed control strategy.

In silico prediction of maximum perineal muscle strain during vaginal delivery by design of experiment

Background and objectiveThe prevalence of pelvic floor muscle injuries induced by childbirth is higher than 23 % in the general women population. Such injuries can lead to prolapses and other pathologies in future female life. Leveraging computational biomechanics, the study implements an advanced female pelvic floor model for computing the maximum pelvic muscle strain, which serves as an injury risk indicator. The design of experiment method, abbreviated as DoE, is used to compute the maximum strain for boundary values of bony pelvis dimensions, namely the anterior-posterior diameter (abbreviated as APD) and the transverse diameter (abbreviated as TD). This is done in combination with small, medium and large percentiles of fetal head circumference (abbreviated as HC). MethodsWe utilized a previously developed finite element model of a female pelvic floor, as a reference, and enhanced it with new features, including a more detailed tissue geometry and advanced constitutive material models. The APD and TD dimensions were sourced from the set of MRI of 64 nulliparous women. This data was used to estimate the boundary dimensions of the female bony pelvis, combining both small and large values of APD and TD. Together with the 10th and the 95th percentiles for HC, a three-dimensional domain was constructed to assess the maximum pelvic muscle strain. In boundary cases, the maximum pelvic muscle strain was computed across 8 full-factorial design models (each situated at one corner of the domain, thereby combining the minimum and the maximum values of APD, TD and HC). This was done to define a response surface that predicts the maximum pelvic muscle strain within the domain. The accuracy of this response surface prediction was validated using 15 additional intermediate design models. These models were placed at the center of the domain (1 point), the centres of the domain boundary surfaces (6 points), and midway along each domain boundary edge (8 points). ResultsThe maximum strain results for 8 combinations of APD, TD, and HC were employed to construct a linear response surface as a function of APD, TD, and HC. Tests at an additional 19 domain points served to evaluate the efficiency of the response surface prediction. The response surface demonstrated strong predictability, with an absolute average error of 1.52 %, an absolute median error of 1.52 %, and an absolute maximum error of 11.11 %. HC emerged as the most influencing dimension, accounting for 16 % of influence. ConclusionsThe reference finite element pelvic floor model was scaled to 8 full-factorial female-specific pelvic floor models, which represent the combination of boundary values for APD, TD, and HC. The maximum pelvic floor muscle strain from these 8 models was used to design a response surface. When implementing the DoE approach to construct the response, there was consistent predictability for the maximum perineal muscle strain, as validated by the additional 19 intermediate design models. As a result, the response surface methodology can serve as an initial predictor for potential childbirth-induced pelvic floor muscle injury.

Weyl Fermions and broken symmetry phases of laterally confined 3He films

Broken symmetries in topological condensed matter systems have implications for the spectrum of Fermionic excitations confined on surfaces or topological defects. The Fermionic spectrum of confined (quasi-2D) 3He-A consists of branches of chiral edge states. The negative energy states are related to the ground-state angular momentum, , for Cooper pairs. The power law suppression of the angular momentum, for , in the fully gapped 2D chiral A-phase reflects the thermal excitation of the chiral edge Fermions. We discuss the effects of wave function overlap, and hybridization between edge states confined near opposing edge boundaries on the edge currents, ground-state angular momentum and ground-state order parameter of superfluid 3He thin films. Under strong lateral confinement, the chiral A phase undergoes a sequence of phase transitions, first to a pair density wave (PDW) phase with broken translational symmetry at . The PDW phase is described by a periodic array of chiral domains with alternating chirality, separated by domain walls. The period of PDW phase diverges as the confinement length . The PDW phase breaks time-reversal symmetry, translation invariance, but is invariant under the combination of time-reversal and translation by a one-half period of the PDW. The mass current distribution of the PDW phase reflects this combined symmetry, and originates from the spectra of edge Fermions and the chiral branches bound to the domain walls. Under sufficiently strong confinement a second-order transition occurs to the non-chiral ‘polar phase’ at , in which a single p-wave orbital state of Cooper pairs is aligned along the channel.

Possible globularization mechanism in LPBF additively manufactured Ti-6Al-4 V alloys

Owing to the great technical significance such as better balance of strength and toughness, the conversion of lamellar to globular microstructure finds its great importance. In order to obtain globular microstructure, it is necessary to shed light on the globularization mechanisms. This paper attempts a systematic study on globularization of Laser Powder Bed Fusion (LPBF) processed Ti-6Al-4 V alloy including microstructure evolution and globularization mechanism. Annealin g was performed in the α + β field, in attempting to transform the acicular α’-martensite into globular microstructure. The required driving force for static globularization during annealing is achieved with the presence of defects such as dislocations and twins which is inherently present within α’-martensite. The static globularization fraction increases with increasing annealing temperature. During annealing, the static globularization involved the evolution of sub-boundaries, phase transformation, and coarsening of α-phase. Furthermore, the possible mechanism was explored through various characterization techniques such as SEM, EBSD and TEM analysis. Globularization mechanisms such as boundary splitting, direct cylinderization, edge spheroidization, termination migration, and Ostwald ripening have been observed. Most of the mechanism activates at higher annealing temperature close to β-transus temperature. The globularization has not taken place homogeneously in the microstructure causing globularization heterogeneity. The inability of achieving a full globularization in LPBF additively manufactured Ti-6Al-4 V alloy is due to its characteristic α-lamellae microstructure such as aspect ratio and morphology.

Dynamical characteristics of fastening of a cylindrical shell with a hemispherical shell made of graded porous power ceramic-metal under elastic boundary edges

For the first time, the dynamical assessment of the fastened hemispherical-cylindrical shell structure (FHCSS) made of porous functionally graded ceramic-metal (FGCM) materials under elastic edge conditions is carried out here. In conformity with this, three forms of pores’ distributions add the effect of the pores on the power law FGCM materials. Add-on, ten artificial springs, including six transition and four rotational springs at the start and end of the FHCSS, determine the effect of the elastic edge constraints on the system's dynamic. In addition, the influential relationships of the shell elements of the FHCSS are set up by combining the first shear deformation theory and Donnell's simplifications. Additionally, Hamilton's principle sets up the influential motion equations (IMEs) of shell elements of the FHCSS. Then, a mesh-less procedure, named the generalized differential quadrature method, is set up to discretize the IMEs, fastening equations, and edge equations of the shell elements of the FHCSS. Also, the standard eigenvalue is set up to determine the natural frequencies of the FHCSS. Finally, various novel examples are set up and solved to indicate the effect of the material values, pores, elastic boundary constraints, and geometrical appearance values on the responses of the FHCSS.

Nonlinear vibrations of doubly curved micropanels reinforced by graphene nanoplates in length direction under non-uniform thermal loading

Structures made of composites are quite common in different industries entailing automotive, marine, and aircraft industries, thanks to their favorable lightweight and strength. This study investigated the nonlinear vibrations of the various shapes of size-dependent graphene nanoplatelets reinforced micropanels under non-uniform thermal loading. In diverse ways in the axial direction, the material characteristics of graphene nanoplates (GPLs) alter. Taylor’s series expansion terms in curvature coordinates are used to illustrate the displacement field. Nonlinear von Karman theory and Hamiltonian principle work together to derive the nonlinear form of the pertinent equations and boundary conditions. Strain gradient theory with consideration for inherent length scale characteristics is investigated to account for size effects. By discretizing the spatial domain equations, deriving Duffing-type equations, and using Kronecker and Hadamard products, the governing equations and numerous nonlinear boundary edges are resolved. Using the techniques and answers outlined above, the results section is produced. There are four sections for this research. The findings are cross-checked with those from other studies that have been published in the first section. The effects of geometric and physical factors are shown in Parts 2, 3, and 4 on the nonlinear to linear frequency curve, the nonlinear frequency curve, and the sensitivity of the nonlinear frequency-to-size effect (SNFSE).

Noise Reduction on a Low Reynolds Number Propeller

With the mass application of drones in daily work, more attention has been paid to the noise problem. The noise generation mechanism of low Reynolds number propellers is studied in this paper. It is found that there are laminar separation bubbles on the suction surface, causing an increase in broadband noise. Leading edge boundary layer trips are added to remove the bubbles. Finally, experimental measurements indicate that isolated propeller noise reduction is up to 5 dBA. It still has a 1.5 dBA reduction in the full-loaded hovering drone test, which brings many conveniences for daily work.

IMPLEMENTASI METODE DETEKSI TEPI CANNY UNTUK MENGHITUNG JUMLAH UANG KOIN DALAM GAMBAR MENGGUNAKAN OPENCV

Edge detection is often used in image processing to find the edge boundaries of image objects and this is important for selecting the edges of image parts. The image edge detection used in this study counts coins in an image, so that it can easily pass through the human eye but not by a computer. In a computer system, it is necessary to provide programs and test data so that the computer can read and count coins like a human. The purpose of this study is to count coins in an image using Canny edge detection and Gaussian filtering methods. The images used in this study are in the form of *jpg and tested using the Visual Studio Code application using OpenCV and Python. The results of this study indicate that the results of the number of coins read from the images inputted to the system can be read properly, with a data accuracy of 90%. Canny's edge detection method can be used to count the number of coins in an image.Keywords: Pengolahan Citra; Deteksi tepi Canny; Gaussian filtering; OpenCV;

A Cloud-Edge Computing Method for Integrated Electricity-Gas System Dispatch

An integrated electric–gas system (IEGS) is the manifestation and development direction of a modern smart power system. This paper employs the cloud-edge computing method to research IEGS’s optimal dispatch to satisfy data protection requirements between power systems and natural gas systems and reduce data transmission pressure. Based on cloud-edge computing architecture, this paper constructs a cloud-edge computing method based on the Multi-agent Deep Deterministic Policy Gradient (MADDPG) algorithm to solve optimal dispatch problems. Then, this paper proposes an IEGS dispatch strategy based on cloud-edge computing, which conducts distributed computing independently at the edge of power and natural gas, and the cloud implements global dispatch based on boundary information and edge learning parameters. This method does not require the exchange of all information between the power system and natural gas system, effectively protecting data privacy. This paper takes the improved IEGS of the IEEE 9 node and Gas 8 node as an example to analyze. The equipment output of this dispatch method is within a reasonable range, and the cost is reduced by 0.21% to 1.03% compared with other methods, which verifies the effectiveness of the cloud-edge computing method in solving dispatch problems.

Free in-plane vibration of irregular laminated plate with curved edges based on boundary-type Chebyshev–Ritz method

The free in-plane vibration characteristics of laminated plate with arbitrarily geometrical shape and generally restrained edges, including curved and inclined edges, are investigated based on the boundary-type Chebyshev–Ritz method (BCRM). By adopting the divergence theorem, the double integral encountered in solving the energy equation of irregular laminates is converted to the integral on the boundary edge, which effectively reduces the computational complexity of the involved domain. The Chebyshev polynomials are utilized as test functions and the primitives of domain integrand functions are deduced according to the properties of Chebyshev polynomials. General boundary conditions on straight or even curved edges are achieved by introducing normal and tangential springs and assigning reasonable stiffness values. Natural frequencies and modes of laminated composite plates with straight edges (triangle, square, trapezoid, and hexagon), laminated composite plates with curved edge (ellipse), and irregular laminated composite plates are obtained. The method validation is carried out by comparison of the obtained solutions with literature and finite element results. The effects of variations in layering mode, number of layers, boundary conditions, and geometry on the eigenpairs of composite plate are extensively discussed.

Membrane-Active Peptides Attack Cell Membranes in a Lipid-Regulated Curvature-Generating Mode.

Membrane-active peptides (MAPs) exhibit great potential in biomedical applications due to their unique ability to overcome the cell membrane barrier. However, the interactions between MAPs and membranes are complex, and little is known about the possibility of MAP action being specific to certain types of membranes. In this study, a combination of molecular dynamics simulations and theoretical analysis was utilized to investigate the interactions between typical MAPs and realistic cell membrane systems. Remarkably, the simulations revealed that MAPs can attack membranes by generating and sensing positive mean curvature, which is dependent on lipid composition. Furthermore, theoretical calculations demonstrated that this lipid-regulated curvature-based membrane attack mechanism is an integrated result of multiple effects, including peptide-induced membrane wedge and softening effects, the lipid shape effect, the area-difference elastic effect, and the boundary edge effect of formed peptide-lipid nanodomains. This study enhances our comprehension of MAP-membrane interactions and highlights the potential for developing membrane-specific MAP-based agents.

Cryogenic Fracture Proliferation from Boreholes under Stresses

Cryogenic fracturing has been explored in recent years as a waterless fracturing method for well stimulation to avoid issues encountered in water-based hydraulic fracturing. Cryogenic stimulation using liquid nitrogen applies large thermal gradients on reservoir rocks to induce fractures. This study investigates the initiation and proliferation of cryogenic fractures from boreholes under external stress on specimens. We flowed liquid nitrogen through boreholes drilled through the center of transparent PMMA cylinders under uniaxial stress and monitored fracture proliferation, temperatures, and borehole pressures. Our results show that the effect of stress resembles that of hydraulic fractures such that fractures propagate more in the direction of the stress. Under loading perpendicular to the borehole axis, a cloud of annular and longitudinal fractures extends more in the direction of loading. Under loading parallel to the borehole axis, longitudinal fractures dominate, and annular fractures become more suppressed and more sparsely distributed than those of unconfined specimens. Even if fractures are driven to initiate against the influence of stress, such as those from a boundary edge of a high stress concentration, they gradually deflect in the direction of stress, similar to hydraulic fractures from perforation holes that curve toward a direction perpendicular to the minimum stress direction.

OPENPLC HARDWARE SPEED PERFORMANCE COMPARISON

Programmable Logic Controllers (PLCs) are critical components in industrial automation. As the technology behind PLCs continues to evolve, there is an ever-growing range of PLC hardware available in the market and their performance and functionality can vary significantly. Choosing the right PLC for a given application is thus a challenging task, requiring a thorough understanding of the available options and their capabilities. This approach involves running benchmarking tests on different PLCs to measure their performance and compare them. In this article, we compare the edge boundaries of time-based parameters of different PLC hardware, including open-source embedded controllers (Arduino and ESP8266) working with software such as OpenPLC and also Wago programmable logic controller PFC200 Keywords: OpenPLC, Programmable Logic Controller, PLC Benchmark, Speed Test

Motion Context guided Edge-preserving network for video salient object detection

Video salient object detection targets at extracting the most conspicuous objects in a video sequence, which facilitate various video processing tasks, e.g., video compression, video recognition, etc. Although remarkable progress has been made for video salient object detection, most existing methods still suffer from coarse edge boundaries which may hinder their usage in real-world applications. To alleviate this problem, in this paper, we propose a Motion Context guided Edge-preserving network (MCE-Net) model for video salient object detection. MCE-Net can generate temporally consistent salient edges, which are then leveraged to refine the salient object regions completely and uniformly. The core innovation in MCE-Net is an Asymmetric Cross-Reference Module (ACRM), which is designed to exploit the cross-modal complementarity between spatial structure and motion flow, facilitating robust salient object edge extraction. To leverage the extracted edge features for salient object refinement, we fuse them with multi-level spatial–temporal embeddings in a paralleled guidance manner, generating the final saliency results. The proposed method is end-to-end trainable and the edge annotations are generated automatically from ground truth saliency maps. Experimental evaluations on five widely-used benchmarks demonstrate that our proposed method can achieve superior performance to other outstanding methods. Moreover, the experimental results indicate that our method can preserve salient objects with clear boundary structures in video sequences.

Nonlinear dynamic analysis and vibration suppression on the composite laminated plates with general boundary conditions in supersonic airflow

This paper performs the nonlinear dynamic analysis and vibration reduction of the panel structures subjected to supersonic airflow. The negative capacitance piezoelectric shunt damping circuit (PSDC) which contains bonded piezoelectric element and external negative capacitance is adopted. Based on the modified Ritz approach and energy approach, the formulations of the nonlinear panel structure with attached piezoelectric element are derived. A unified mathematical model for the nonlinear dynamic analysis of composite panels subjected to general edge boundaries in supersonic airflow is formulated. Furthermore, the Newmark approach and Newton iteration approach are utilized to calculate time domain responses of panel structures under aerodynamic pressure. Several numerical cases are further performed to verify the present formulations. Finally, impacts of several factors on the flutter characteristics of panel structures are investigated and the comparisons concerning the vibration responses of panels having and without PSDC are performed to verify vibration reduction properties of the present method. The numerical results show that the vibration and flutter of panels in supersonic airflow can be sufficiently suppressed by the present simple vibration reduction strategy.

Neilan's divergence‐free finite elements for Stokes equations on tetrahedral grids

AbstractThe Neilan ‐ divergence‐free finite element is stable on any tetrahedral grid, where the piece‐wise polynomial velocity is on the grid, on edges and at vertices, and the piece‐wise polynomial pressure is on edges and at vertices. However the method does not work if the exact pressure solution does not vanish on all domain edges, because of the excessive continuity requirements. We extend the Neilan element by removing the extra requirements at domain boundary edges. That is, if a vertex is on a domain boundary edge and if an edge has one endpoint on a domain boundary edge, the velocity is only at the vertex and on the edge, respectively, and the pressure is totally discontinuous there. Under the condition that no tetrahedron in the grid has more than one face‐triangle on the domain boundary, we prove that the extended finite element is stable, and consequently produces solutions of optimal order convergence for all Stokes problems. A numerical example is given, confirming the theory.

A novel Gateaux derivatives with efficient DCNN-Resunet method for segmenting multi-class brain tumor.

In hospitals and pathology, observing the features and locations of brain tumors in Magnetic Resonance Images (MRI) is a crucial task for assisting medical professionals in both treatment and diagnosis. The multi-class information about the brain tumor is often obtained from the patient's MRI dataset. However, this information may vary in different shapes and sizes for various brain tumors, making it difficult to detect their locations in the brain. To resolve these issues, a novel customized Deep Convolution Neural Network (DCNN) based Residual-Unet (ResUnet) model with Transfer Learning (TL) is proposed for predicting the locations of the brain tumor in an MRI dataset. The DCNN model has been used to extract the features from input images and select the Region Of Interest (ROI) by using the TL technique for training it faster. Furthermore, the min-max normalizing approach is used to enhance the color intensity value for particular ROI boundary edges in the brain tumor images. Specifically, the boundary edges of the brain tumors have been detected by utilizing Gateaux Derivatives (GD) method to identify the multi-class brain tumors precisely. The proposed scheme has been validated on two datasets namely the brain tumor, and Figshare MRI datasets for detecting multi-class Brain Tumor Segmentation (BTS).The experimental results have been analyzed by evaluation metrics namely, accuracy (99.78, and 99.03), Jaccard Coefficient (93.04, and 94.95), Dice Factor Coefficient (DFC) (92.37, and 91.94), Mean Absolute Error (MAE) (0.0019, and 0.0013), and Mean Squared Error (MSE) (0.0085, and 0.0012) for proper validation. The proposed system outperforms the state-of-the-art segmentation models on the MRI brain tumor dataset.

A Novel Method Using the Petal Pattern for Contouring a Domed Nipple in Tuberous Breasts.

The main cause of domed nipples is increased pressure, which causes the breast tissue to herniate toward the nipple-areola complex. It appears as a characteristic of a tuberous breast rather than occurring alone, and the boundary between the nipple and areolar region is unclear. The authors present a method using petal patterns for single-stage aesthetic correction of domed nipples. The method is designed by placing the left and right corners of each petal at the desired position as the edge boundary of the nipple. The number and width of petals are adjusted so that the obtuse angle between the nipple and areola is 90 to 100 degrees. The areolar and soft tissues in the designed patterns are excised together with the skin and collected using a barbed suture in a specially designed suture technique. Surgery is completed after the skin is sutured using nylon. Case examples are presented to illustrate the appropriate candidate selection and results. Overall, the aesthetic results are positive in terms of shape and patient satisfaction. This method is useful for contouring domed nipples. This new design is simple, leaves minimal scars, and provides the surgeon with an additional option for treating tuberous breasts. It can be used alone or along with breast augmentation.

Intelligent and trusted metaheuristic optimization model for reliable agricultural network

Artificial intelligence (AI) is gaining demanding growth in the field of smart cities, agriculture, food management, and weather forecasting due to the lack of computing power on sensing devices. The applications of artificial intelligence are integrated with various Internet of Things (IoT) and ubiquitous sensors for the improvement of the agriculture sector and to decrease its management cost. Due to the bounded resources of wireless technologies, most of the solutions are designed for efficient delivery of agriculture data to cloud systems, however, still optimizing the resources management and data load for forwarding nodes, especially those closest to edge boundaries is a challenging issue. Moreover, due to the collection of incorrect environmental data, the decision-making process leads to a decrease in the productivity of the optimization process. To overcome such issues, this work proposes a trustworthy and intelligent agricultural model that uses metaheuristic optimization to enhance resource management to address these problems. The proposed model approach employs the decision-making function to overcome information loss and inconsistency. Moreover, it builds trust in agricultural data collection by using secure IoT devices and facilitating reliable communication. In terms of performance metrics, the proposed model is simulated to assess its importance in comparison to state-of-the-art solutions. It not only collects updated data from agricultural land but also uses artificial intelligence's lightweight optimization technique to reduce the overheads on IoT devices. The experiment findings demonstrate the importance of the proposed model for resource monitoring and overheads on the IoT system.

On the mechanics of a double thin film on a finite thickness substrate

The single edge loading problem of a double thin film deposited on a finite thickness substrate is considered. The films and the substrate are assumed to be homogeneous and isotropic. The membrane analogy is adopted for the films and two dimensional elasticity is applied to the substrate. The compatibility of the tangential strain between the film and the substrate yields the governing singular integral equation in terms of the interfacial shear stress. The numerical solution is provided using the Gauss–Chebyshev discretization method. The sensitivity of the interfacial shear and the normal stresses to several effective parameters are examined. The results of current study are compatible with the finite element simulations. The lowest interfacial shear stress pertains to a substrate with a free edge boundary condition. The results of current study are applicable to the debonding failure assessment of the multi-layer joints and semiconductors which are susceptible to the interfacial shear stresses near the film edges.