Practical Engineering Applications Research Articles

Mixed convective heat transfer to flexible viscosity nanofluid over a radially elongated convective exterior with temperature dependent heat source and Arrhenius activation energy

Purpose This study aims to explore the collective influence of several factors, namely, thermal radiation, Brownian motion, magnetic field and variable viscosity parameter, on the boundary layer flow, heat and mass transfer of an electrically steering nanofluid over a radially stretching exterior subjected to convective heating. In addition, the impacts of thermal and solutal buoyancy forces and activation energy are taken into account. The enlarging velocity is assumed to vary linearly with radial distance. Design/methodology/approach Through the similarity transformation technique, the governing highly nonlinear partial differential equations are transformed into a set of nonlinear ordinary differential equations, which are then numerically solved using the Runge–Kutta–Fehlberg method with a shooting technique. Findings Graphical depictions are provided to analyze the velocity, temperature and nanoparticle concentration fields under the influence of various pertinent parameters. Furthermore, local skin friction, local Nusselt and Sherwood numbers are quantitatively presented and discussed. A comparison with previous results demonstrates good agreement. Originality/value This study uniquely integrates multiple factors influencing boundary layer flow in electrically conducting nanofluids, offering a nuanced understanding of heat and mass transfer over radially stretching surfaces. By using advanced numerical methods, it provides valuable insights and quantitative data that can inform practical applications in engineering and materials science.

Coherent characteristics of broadband and extended light sources based on the Twyman–Green interferometer

The Twyman–Green interferometer, as a representative type of interferometric structure, possesses unique advantages in the field of interferometry due to its adjustable single optical path characteristic. However, using a laser as the light source for the Twyman–Green interferometer, with its long coherence length, can result in noisy fringes when measuring planar elements, including multiple surface interference fringes and speckle noise. To address these issues, this paper proposes the use of broadband extended light source as the coherent light source in the Twyman–Green interferometer to achieve short coherent source illumination, thereby eliminating interference fringes and coherent noise. This paper theoretically derives the coherence characteristics of broadband extended light sources and, in particular, quantitatively analyzes the influence of the thickness difference of glass in the Twyman–Green dual optical paths on the contrast of the interference fringe. The corresponding theoretical expressions for interference intensity are derived, and the validity of these theoretical findings is demonstrated through simulation analysis and experimental verification. This innovative research, to our knowledge, significantly supplements the existing coherence theory of light sources, offering substantial theoretical research insights and practical engineering applications.

A Method for Detecting Small Target Weld Defects Based on Feature Reorganization Network

Abstract In the process of intelligent weld seam inspection, small weld seams are often prone to false detections or omissions. Existing methods simply concatenate feature segments during the upsampling process without analyzing the importance of each feature segment, leaving room for further improvement in detection accuracy. To address these issues, this study proposes a Feature Reorganization Network (FRNet) for detecting small target weld defects. First, the C2f-Faster-EMA feature extraction module is designed using GSConv convolution, and the LSKNet is introduced to dynamically adjust the receptive field of the backbone in the Backbone section, enhancing the model's ability to extract small target features. Then, a lightweight CARAFE upsampling module is designed in the neck network, which retains more detailed information through feature reorganization and feature expansion, and introduces the parameter-free attention mechanism SimAM to fully capture the contextual information of small targets, thereby enhancing the proposed model's ability to extract small target features. Finally, the GIoU boundary loss function is used to improve the network's bounding box regression performance, achieving intelligent detection of small target weld defects. Experimental results show that the proposed method achieves a mean average precision, parameter count, and computation volume of 85.6%, 2.5M, and 7.0G, respectively, for weld defect detection, outperforming the comparison models and meeting the requirements of practical engineering applications.

Research on rock breaking mechanism of PDC cutter under the action of ultrasonic vibration.

Ultrasonic vibration technology has significant potential for breaking hard rocks. Understanding the optimal frequency for rock breaking under ultrasonic vibration can significantly reduce the cost of rock breaking and extend the service life of polycrystalline diamond compact (PDC) cutters. This is important for practical engineering applications. This study presents a three-dimensional finite element model of rock breaking by a PDC cutter under ultrasonic vibration. The model was established using ABAQUS software and used to simulate the dynamic rock breaking process of the PDC cutter. A comparative analysis was performed between conventional rock breaking and rock breaking under ultrasonic vibration. According to the result, ultrasonic vibratory rock breaking is more likely to cause damage to the rock when a PDC cutter is used, particularly at a vibration frequency of 40 kHz. As the ultrasonic vibration frequency (20-40kHz) increases, the mechanical specific energy (MSE) initially decreases and then increases. The MSE reaches a minimum value at a frequency of 20-25 kHz, representing a decrease of 15.52%-22.24% compared with conventional rock breaking, which can significantly improve the rock breaking efficiency and reduce the drilling cost. The temperature of the PDC cutter increases significantly under ultrasonic vibration compared with conventional rock breaking. Additionally, the temperature of the PDC cutter increases gradually with an increase in the vibration frequency. These results provide theoretical support for the use of ultrasonic vibration technology.

The Impact of Camber Variation on NACA 2412 Airfoil Efficiency and Its Implications for Adaptive Engineering Solutions

This paper investigates the effects of varying the camber on the aerodynamic efficiency of the NACA 2412 airfoil by analyzing the Lift-to-Drag (L/D) ratio. Using wind tunnel tests at a constant speed of 95 MPH, data was collected for different camber configurations, and L/D ratios were computed for each trial. The NACA 2412 airfoil camber was modified to increase the camber by 20%, decrease it by 20%, and decrease surface area by 20%. These were all tested at Angle of Attack values from 0 to 30 in 5-degree increments. The results revealed a strong correlation between camber variation and aerodynamic efficiency, with certain camber settings significantly enhancing performance at specific Angles of Attack. While the original NACA 2412 served as a control, modifications such as reduced camber and surface area demonstrated significant efficiency changes, underscoring the role of camber in optimizing performance. The study provides valuable insights for optimizing airfoil design, offering practical applications in aircraft engineering, particularly in the development of systems that can adapt wing geometry dynamically to optimize performance. However, limitations such as fixed airspeed and limited camber variations were noted, highlighting the need for further investigation into more diverse conditions. These findings contribute to a broader understanding of how engineering solutions can enhance aircraft performance by incorporating adaptable design elements.

Advances in polysaccharide-based materials for biomedical and pharmaceutical applications: A comprehensive review.

Polysaccharides, the most abundant biopolymers in nature, have attracted the attention of researchers and clinicians due to its practicality in biomedical and pharmaceutical sciences. These biomaterials have high bioavailability and play structural and functional roles in living organisms. Polysaccharides are classified into several groups based on their origin, including plant polysaccharides and marine polysaccharides (like chitosan, hyaluronic acid, dextran, alginates, etc.) with specific applications. These biopolymers possess unique physicochemical (such as surface functional groups, solubility, and stability), mechanical (like mechanical strength and tensile), and biomedical (such as antioxidant activity, biocompatibility, biodegradability, renewability, and non-immunogenicity) characteristics which have made them excellent platforms for a wide variety of biomedical and pharmaceutical applications. Ease of extraction and different preparation approaches are mentioned as other potential properties of polysaccharides that further improved their practicality in biomedical sciences. They have high drug/bioactive encapsulation capacity and sustained/controlled release manner in in vivo microenvironments. The anti-inflammatory and immunomodulation, stimuli-responsive drug/bioactive release, and passive and active drug/bioactive delivery are considered the potential features of these biopolymers in pharmaceutical sciences. Polysaccharides have indicated practical applications in biomedical sciences, including biosensors, tissue engineering, implantation, wound healing, vascular grafting, and vaccines. This review highlights the advances of polysaccharide-based materials in biomedical and pharmaceutical sciences.

Tensile Test of Chicken Feather Fibre Composite Material and Application

The purpose of this study is to perform the tensile tests on chicken feather fiber composites to evaluate their potential in practical engineering applications. The study employed the experimental method as a laboratory activity, in which chicken feathers fibers were fused with epoxy resin at different ratios of 5%, 10%, 12% and 14% to form composite specimens. In order to find the ultimate tensile strength, yield strength and the modulus of elasticity of the composites, tensile testing of the composites was done according to the the American Society of Testing and Materials (ASTM) D3039 standard test method. Results showed that in as low as 5% cement reinforcement of chicken feathers, the mechanical properties of the resin were greatly improved, with the ultimate tensile strength reaching 48.672 N/mm² and the yield strength being 39.168 N/mm². This shows the promise of using chicken feather fiber composites as strong and light materials that are also eco-friendly for various uses. The discussion topics mentioned the behavior of stress-strain transition from elastic to plastic region on increasing the load, which showed the strength and flexibility of the composites are in essence, the opposite of each other. This study advances the view that there is more development to be done on chicken feather fiber composites to enable them satisfy the standards of various sectors thereby offering an environmentally friendly method in cutting waste and reducing the burden of the environment from synthetic materials.

Experimental and Numerical Investigations of the Sediment Abrasion Mechanism at the Leading Edge of an Airfoil

Multiple engineering projects have confirmed that hydraulic machinery operating in sediment-laden rivers undergoes sediment abrasion. Guide vanes are among the most severely worn flow-passing components and have long been a key research focus in hydraulic machinery. In this research, a wear test of the NACA0012 cascade under a 10° incoming flow angle was carried out in the Venturi test system, and the evolution process of the wear was analyzed. The three-dimensional flow channel of the cascade was constructed, and the Finnie wear model was adopted for computational fluid dynamics (CFD) simulations to analyze the wear mechanism at the initial stage. The results indicate that abrasion primarily occurs at the airfoil’s leading edge and progresses through three stages: initiation, development, and stabilization. The calculated results closely matched the latest wear outcomes: In the initial stage, the wear rate density was influenced by the particle impact velocity, angle, volume fraction, and y-direction shear stress. A low-velocity zone near the impact point, combined with rebounding particles causing secondary impacts, increases the particle volume fraction and wear rate density. These secondary impacts are the primary causes of erosion on both the upstream and downstream surfaces. Furthermore, flow separation downstream from the leading edge makes this region highly susceptible to wear. This study provides valuable insights for addressing wear in hydraulic machinery for practical engineering applications.

A Comprehensive Model and Numerical Study of Shear Flow in Compressible Viscous Micropolar Real Gases

Understanding shear flow behavior in compressible, viscous, micropolar real gases is essential for both theoretical advancements and practical engineering applications. This study develops a comprehensive model that integrates micropolar fluid theory with compressible flow dynamics to accurately describe the behavior of real gases under shear stress. We formulate the governing equations by incorporating viscosity and micropolar effects and transform the obtained system into the mass Lagrangian coordinates. Two numerical methods, Faedo–Galerkin approximation and finite-difference methods, are used to solve it. These methods are compared using several benchmark examples to assess their accuracy and computational efficiency. Both methods demonstrate good performance, achieving equally precise results in capturing essential flow characteristics. However, the finite-difference method offers advantages in speed, stability, and lower computational demands. This research bridges gaps in existing models and establishes a foundation for further investigations into complex flow phenomena in micropolar real gases.

Effect of pore plugging on transpiration cooling performance implemented with perforated flat plates

Transpiration cooling is expected to be one of the most effective cooling technologies for gas turbine blades. However, dust deposition can easily lead to pore plugging, which limits its practical application in engineering. The plugging of pores in conventional porous media models is difficult to predict, so it is essential to construct computational models with finely controllable porous structures. In this study, a transpiration cooling configuration with straight holes perforated with a diameter of 0.5 mm was adopted. The effects of plugging ratio and region on flow and heat transfer under different coolant injection ratios and pump power conditions were investigated by numerical simulation. The results showed that at constant mass flow rate, the overall cooling performance increased as the plugging ratio increased at low injection ratios. At high injection ratios, the opposite was true. With a certain pump power, as the plugging rate increased, the flow loss coefficient rose, leading to a decrease in cooling efficiency. Transpiration cooling efficiency was also highly sensitive to the distribution of plugged holes at the same plugging ratio. When the coolant flow was sufficient, the farther the plugged area was from the leading edge, the smaller the reduction in cooling efficiency.

Periodic orbits and bifurcation of a two-degree-of freedom dry friction coupled vibration system

Abstract This article explores the dynamic behavior of a two-degree-of freedom dry friction coupled vibration system. By constructing a generalized Poincaré map and obtaining the necessary and sufficient conditions for the existence of invariant cone in the system, the linearization principle of Poincaré map is equivalently replaced by the study of a global monodromy matrix. Based on the Floquet theory, the stability of the invariant cone consists of periodic orbits is proved, and the bifurcation phenomenon and persistence of the invariant cone under parameter changes are explored. The distribution configuration of the trajectory is given through numerical simulation, verifying the accuracy of the theory. This provides a theoretical basis for parameter optimization and vibration control of high-dimensional dry friction vibration systems in practical engineering applications.

Dynamic compressive properties and constitutive model of waste crumb rubber (CR) modified ultra-high performance engineered cementitious composites (UHP-ECC)

Ultra-high-performance engineered cementitious composites (UHP-ECC) are well-known for their outstanding mechanical properties under static and dynamic loads. However, the effect of modifying UHP-ECC with crumb rubber (CR) on its performance, especially under high strain rates, remains poorly understood. This study systematically examined the dynamic compressive behavior and characteristic failure patterns of CR-modified UHP-ECC under high strain rates using a split Hopkinson pressure bar (SHPB) system. The study focused on evaluating the dynamic compressive strength, stress-strain response, and strain energy density (SED). A dynamic increase factor (DIF) formula was developed based on experimental data, and a nonlinear viscoelastic constitutive model was proposed to predict compressive behavior across various strain rates. Results indicate that while the addition of 10% CR slightly reduces the quasi-static compressive and flexural strength, it significantly enhances tensile ductility. Under high strain rates, CR-modified UHP-ECC shows no substantial effect on peak compressive stress but a marked increase in peak compressive strain. The SED also increased by 20.2%, outperforming other high-performance materials such as UHPC and normal ECC. These findings demonstrate that incorporating 10% CR into UHP-ECC offers considerable advantages, particularly in enhancing structural resilience under dynamic loading conditions. The proposed nonlinear viscoelastic model accurately predicts the compressive behavior of CR-modified UHP-ECC, presenting significant implications for practical engineering applications where high strain rate performance is crucial.

Effects of Symmetric and Asymmetric Pre-Compression Combinations on the Mechanical Properties and Fatigue Behavior of ZK60 Magnesium Alloy

Pre-compression modes influence the microstructure of rolled magnesium alloys, thereby enhancing their mechanical and fatigue properties. This study investigates the distribution of dislocations, extension twins, and texture components in rolled ZK60 magnesium alloy sheets subjected to single-pass pre-compression (S-PT3), symmetric pre-compression (S-PT3R3), and asymmetric pre-compression (S-PT3R6). The results indicate that the variation in the orientation of pre-twin textures, leading to differences in the Schmid factor, is the primary cause of the mechanical performance differences observed under different pre-compression modes. In contrast, the hardening effect due to grain refinement is negligible. As the total amount of pre-compression increases, the hardening effect of pre-dislocations becomes more significant. Single-pass pre-compression exhibits a higher fatigue life under large strain amplitudes. Although asymmetric pre-compressed samples show increased overall strength and hardness, their fatigue life and cyclic stability are inferior. During cyclic loading, different pre-compression modes significantly impact the hysteresis curve, deformation mechanisms, stress ratio, and elastic limit amplitude. Symmetric pre-compression samples exhibit superior cyclic stability and fatigue life. Based on different application requirements, suitable pre-compression treatment methods can be selected to optimize the performance of ZK60 magnesium alloys, providing scientific guidance for practical engineering applications.

Research on Propagation Characteristics of Fracture Grouting in Clay Formation

Splitting grouting is a highly effective technique for reinforcing tunnels and underground structures, ensuring their operational stability and facilitating long-term maintenance. It has been widely adopted in the prevention and remediation of geological hazards. However, the theoretical research on the diffusion mechanisms of split grouting lags behind its practical applications. This study addresses several key scientific challenges in understanding the diffusion behavior of split grouting. By integrating experimental design, numerical simulations, and theoretical analysis, we conduct a systematic investigation into the diffusion process and vein morphology of split grouting in both homogeneous and heterogeneous formations. We first employed a self-developed two-dimensional grouting test system to perform diffusion experiments on cohesive strata, focusing on the influence of various factors such as grout density, water/cement ratio, soil consistency, and fracture characteristics. The results provide insights into the diffusion patterns, morphology, soil pressure distribution, and surface uplift behavior of the grout veins. Subsequently, a numerical simulation program, developed in-house, based on the finite element method (FEM) and the volume of fluid (VOF) approach, was employed to model the entire process of fracturing grouting within clay strata. The experimental and numerical results indicate that grout vein diffusion in layered soil follows a Y-shaped pattern with an inclined deflection. In uniform strata, the surface uplift curve displays both symmetrical and asymmetrical “convex” elevations, while in heterogeneous soft and hard strata, the uplift is characterized by distinct “convex” deformations. Finally, based on these findings and the principles of contact mechanics, we analyze the underlying mechanisms. The results suggest that weak contact zones undergo tensile cracking and horizontal deflection prior to the formation of grout veins. Additionally, local stress rotations in the soil can induce tilting and deflection. The theoretical insights derived from this study provide valuable guidance for practical engineering applications.

A Machine Vision-Based Measurement Method for the Concentricity of Automotive Brake Piston Components

The concentricity error of automotive brake piston components critically affects the stability and reliability of the brake system. Traditional contact-based concentricity measurement methods are inefficient. In order to address the issue of low detection efficiency, this paper proposes a non-contact concentricity measurement method based on the combination of machine vision and image processing technology. In this approach, an industrial camera is employed to capture images of the measured workpiece’s end face from the top of the spring. The edge contours are extracted through the implementation of image preprocessing algorithms, which are then followed by the calculation of the outer circle center and the fitting of the inner circle center. Finally, the concentricity error is calculated based on the coordinates of the inner and outer circle centers. The experimental results demonstrate that, in comparison to a coordinate measuring machine (CMM), this method exhibits a maximum error of only 0.0393 mm and an average measurement time of 3.9 s. This technology markedly enhances the efficiency of measurement and fulfills the industry’s requirement for automated inspection. The experiments confirmed the feasibility and effectiveness of this method in practical engineering applications, providing reliable technical support for the online inspection of automotive brake piston components. Moreover, this methodology can be extended to assess concentricity in other complex stepped shaft parts.

Effect of inoculated sludge concentration on start-up of anammox reactor: Nitrogen removal performance and metabolic pathways

The anammox process is efficient for nitrogen removal but faces challenges due to slow bacterial growth and limited inoculated sludge supply. This study examined the effects of different inoculated sludge concentrations (3.5, 7, and 14 g/L) on start-up and nitrogen metabolism in anammox reactors. Three identical reactors were operated under controlled conditions, with comprehensive analysis of nitrogen removal efficiency, sludge characteristics, and microbial community dynamics through metagenomic and transcriptomic approaches. Results demonstrated that higher inoculated sludge concentrations accelerated reactor start-up, with the 14 g/L reactor achieving stable operation in 13 days compared to 44 days for the 3.5 g/L reactor. However, the improvement in nitrogen removal rate showed a boundary effect, not proportional to the increase in sludge concentration. Notably, reactors with higher inoculated sludge concentrations exhibited lower sludge loads but higher sludge yield coefficients. Metagenomic analysis revealed Candidatus Kuenenia as the dominant anammox bacteria, with decreasing hydrazine dehydrogenase (hdh) gene expression levels observed at higher sludge concentrations, suggesting hydrazine synthesis as a potential rate-limiting step. This study provides novel insights into the optimal range of inoculated sludge concentration for anammox reactor start-up and elucidates the underlying metabolic mechanisms, offering valuable guidance for practical engineering applications.

Research Status and Prospect of the Key Technologies for Environment Perception of Intelligent Excavators

With the urgent need of the industry and the continuous development of artificial intelligence, research into intelligent excavators has achieved certain progress. However, intelligent excavators often face strong vibrations, dense dust, and complex objectives. These have brought severe challenges to environmental perception, and are important research difficulties that must be overcome in realizing the practical engineering applications of intelligent excavators. Many researchers have studied these problems in reducing vibration and dust noise for light detection and ranging (LiDAR) scanners, multi-sensor information fusion, and the segmentation and recognition of 3D scenes. This paper reviews the research status of these key technologies and discusses their development trends.

A numerical approach for inlet-outlet boundary conditions with least-square moving particle explicit (LSMPE) method on GPU

ABSTRACT In severe accidents of nuclear reactors, studying the pressure drop of debris beds is of great significance for delaying the progression of the accident. However, traditional MPS often exhibits significant pressure oscillation issues when dealing with the inlet-outlet boundary. The study introduces a method for managing inlet and outlet boundary conditions using the Least-Square moving particle explicit method (LSMPE). A high-precision least squares discrete method was applied to the moving particle explicit method (MPE) based on predictive-corrected pressure. The code was accelerated using OpenACC for parallelization. Special boundary treatments were applied to minimize errors induced by boundaries, including particle number density correction for inlet particles, addressing slip or nonslip boundaries, and introducing concept particles at the outlet. The stability and accuracy of this method were validated through three cases. Simulation results for Poiseuille flow and circular flow demonstrated the method’s good precision, exhibiting stable pressure fields. Results from single-phase flow simulations through a porous medium bed agreed well with predictions from the Ergun equation, highlighting the method’s potential for practical engineering applications.

Time-domain inversion of random dynamic loads on offshore platforms based on optimized ensemble learning

This paper presents an optimized ensemble learning method tailored for the field of dynamic load identification. The approach utilizes finite element simulation data to train the ensemble learning model and subsequently employs actual measured response data for load inversion. The key feature of this method lies in leveraging ensemble learning to address the inversion problem when the load is unknown, eliminating the need for solving model parameters directly, and directly constructing an inverse model between the response and external load. By employing three ensemble learning models (Extra Trees, AdaBoost, Light GBM) for load inversion, both Extra Trees and AdaBoost yielded an MSE of 0.09, confirming the feasibility of the method. Furthermore, we evaluated its load inversion performance across different measurement points and machine learning models, as well as its effectiveness in frequency domain inversion. These findings hold significant implications for practical engineering applications.

Intelligent Inspection Method for Rebar Installation Quality of Reinforced Concrete Slab Based on Point Cloud Processing and Semantic Segmentation

The rebar installation quality significantly impacts the safety and durability of reinforced concrete (RC) structures. Traditional manual inspection is time-consuming, inefficient, and highly subjective. In order to solve this problem, this study uses a depth camera and aims to develop an intelligent inspection method for the rebar installation quality of an RC slab. The Random Sample Consensus (RANSAC) method is used to extract point cloud data for the bottom formwork, the upper and lower rebar lattices, and individual rebars. These data are utilized to measure the concrete cover thickness, the distance between the upper and lower rebar lattices, and the spacing between rebars in the RC slab. This paper introduces the concept of the “diameter calculation region” and combines point cloud semantic information with rebar segmentation mask information through the relationship between pixel coordinates and camera coordinates to measure the nominal diameter of the rebar. The verification results indicate that the maximum deviations for the concrete cover thickness, the distance between the upper and lower rebar lattices, and the spacing of the double-layer bidirectional rebar in the RC slab are 0.41 mm, 1.32 mm, and 5 mm, respectively. The accuracy of the nominal rebar diameter measurement reaches 98.4%, demonstrating high precision and applicability for quality inspection during the actual construction stage. Overall, this study integrates computer vision into traditional civil engineering research, utilizing depth cameras to acquire point cloud data and color results. It replaces inefficient manual inspection methods with an intelligent and efficient approach, addressing the challenge of detecting double-layer reinforcement. This has significant implications for practical engineering applications and the development of intelligent engineering monitoring systems.