Hole Angle Research Articles

Assembly strategy for inclined-holes based on vision and force

Abstract In robotic part assembly, the unpredictability of part orientations, uncontrollable contact forces, and challenges in maintaining horizontal assembly holes constrain the practical application of robotic assemblies. These factors frequently lead to misalignment, resulting in assembly failures or excessive contact forces that can damage workpieces or robots, thereby increasing economic costs. Consequently, this paper investigates compliant assembly using machine vision, focusing on cylindrical hole assembly. It examines posture estimation for inclined holes. A hole positioning strategy is formulated, comprising a visual initial location stage and a force feedback searching stage, which achieves low-cost and precise positioning of hole parts. To overcome the jamming issues associated with traditional impedance control strategies during the hole insertion stage, a variable compliance center impedance control strategy is introduced. Four experimental setups involving different-sized pegs and holes for inclined holes were developed, the assembly success rate is 94% and 92% when the inclinations of the hole is 30° and 45°, and the peg-in-hole gap is 0.2 mm. The findings confirm that this strategy can accurately complete robotic peg-in-hole automated assembly, address the challenge of inclined hole angles, and improve the precision and efficiency of fully automated robotic assembly with reduced environmental constraints, supporting cost-effective, precise assembly in industrial applications.

Research and Application of the Deviation Reduction Mechanism in Stratified Cutting Drilling of Soft-Fragmented Coal Seams.

In order to solve the problem of drilling deflection, the method of cutting drilling by layers is proposed. The mathematical model of the force of the layered cutting bit was established, and the influencing factors of bit deflection were obtained. The stress equation of the cutting bit is constructed, and the ABAQUS numerical model is established. The influencing factors of the deflection of the bit are analyzed. A comparative industrial test was carried out in the Tunlan Mine. The analysis results show that the main influencing factors of bit deflection are the tangential force on bit f w , the axial force on bit f t , the length of the straightener rod l, the elastic modulus of the surrounding rock E, the length of the straightener bit and reaming bit h, and the diameter of the drilling hole D. When the axial force on the bit is between 120 and 220 KN, the change of axial force has almost no effect on the deviation angle of the drill hole. The change of f w and l is linearly negatively correlated with the bit deviation angle between 50 and 300 mm. Compared with the conventional drill, the horizontal deviation and vertical deviation of the layered cutting bit are reduced by 23% and 43% on average, respectively.

Induced structure and its gradient design on energy absorption properties and failure behavior of aluminum/carbon fiber reinforced polypropylene super hybrid tube

AbstractThe metal/fiber super hybrid tube is a mixture of pure metal and carbon fiber structure, featuring both stable energy dissipation of the metal and good energy absorption efficiency of the composite, with greatly improved lightweight. However, the failure mode of the hybrid tube is unstable and prone to Eulerian buckling, which affects its energy absorption performance. In this work, aluminum alloy/carbon fiber reinforced polypropylene super hybrid tube (Al/CFPP super hybrid tube) have been obtained through the addition of an induced structures, which aims at reducing the maximum peak load generated during collision. The effects of induced grooves and holes structure (number of holes, diameter and row number) on the damage and energy absorption were discussed. The results showed that the initial peak load can be effectively reduced by adding an induction groove structure. When the number of induction holes is 4, the diameter is 5 mm, and the number of rows is 1, the initial peak load decreases by 14.06%, and the total energy absorption is basically unchanged. Additionally, the gradient design of the hole diameter and spacing significantly helped guide the gradual failure of the structure, with the initial peak load decreased by 21.98% and the total absorption energy increased by 20.26%.Highlights Super hybrid structures were developed to improve crashworthiness. The effect of induced grooves energy absorption was analyzed. The effect of hole size and quantity energy absorption were analyzed. A gradient design of hole size and spacing was proposed. The combined of the induction hole and trigger angle was demonstrated.

A Non-Randomized Clinical Study on Temporal Inverted ILM Flap Versus ILM Peel in Macular Hole Larger Than 400 µm in size

Objective:To compare the efficacy of the temporal inverted ILM flap technique versus ILM peeling for better visual outcomes and closure of macular holes larger than 400 µm. Methodology: This was a non randomized controlled study conducted in the Department of Eye Unit 3, Institute of Ophthalmology, Mayo Hospital Lahore from January 2019 to December 2019. Twenty eyes with large macular holes were included; ten eyes were treated with the Temporal Inverted ILM Flap technique, and ten eyes were treated with ILM Peeling. Preoperatively all macular holes in both groups were assessed for visual acuity and size of macular hole on Optical Coherence Tomography (OCT). Postoperatively, one week, one month, three months, and six months, bestcorrected visual acuity (BCVA) was measured using the logarithm of the minimum angle of resolution (logMAR) scale and macular hole (MH) closure was assessed on OCT. The chi-square test was applied taking p-values < 0.05 a significant. Results: Initially, both groups had an average BCVA of 0.54 ± 0.1 logMAR. After 6 months, the group that underwent Temporal Inverted ILM Flap surgery showed a notable enhancement in BCVA (0.30 ± 0.08 logMAR) in comparison to the group that underwent ILM Peeling surgery (0.40 ± 0.08 logMAR, p = 0.012). There was a higher rate of Type 1 closure (90% compared to 60%, p = 0.011) and better continuity of the ellipsoid zone (100% compared to 80%, p = 0.12) in the group that utilized the temporal inverted flap method as compared to simple ILM peel. Conclusion: Temporal Inverted ILM Flap approach is more effective than ILM peeling in terms of better visual acuity, higher type 1 closure rate, and better continuity of the ellipsoid zone. Keywords: ILM Peeling, Macular Hole, Retinal Surgery, Temporal Inverted ILM Flap, Visual Acuity

Temperature Distribution of Frozen Wall Formed by Irregular Hole Arrangement During In Situ Repair of Underground Shield Machine

In order to study the development law of the irregular hole freezing temperature field, combined with the shield solution project of the Nanjing Water Supply Corridor, the distribution characteristics and influencing factors of the irregular freezing temperature field of the river bottom shield machine are studied by numerical simulation. The following conclusions are obtained: (1) The extension length of the outer ring pipe is correlated approximately positively with the thickness and average temperature of the freezing wall at the bottom of the cup. The thickness increases by 0.25 m, and the average temperature decreases by 1.25 °C for every 1 m increase in the extension length. (2) The intersection time decreases logarithmically with the increase in the extension length of the outer ring tube. (3) As the ratio of the axial angle between the two adjacent tubes in the weak area of the outer ring tube becomes larger, the temperature of the weak point in the center of the two tubes increases approximately linearly. The midpoint temperature of the two tubes increases by 3.3 °C for every 1 increase in the angle coefficient. (4) With the increase in the opening angle of the inner ring hole, the thickness and average temperature change, respectively, at 150 d are not more than 0.15 m and 0.6 °C. The results show that under the irregular freezing form, the angle and length of the outer ring pipe have a great influence on the temperature field, and the angle of the inner ring pipe has little influence on the final distribution of the temperature field. The average temperature and the temperature distribution of the weak points show a trend of decreasing first and then increasing along the shield advancing direction, reaching a minimum near the cutterhead.

Mechanical effect of taper position in abutment hole and screw taper angles on implant system and peri-implant tissue: a finite element analysis

Purpose The study aimed to investigate the mechanical effects of the taper position in the abutment hole and the screw taper angles on the implant system and peri-implant tissue using finite element analysis. Methods Four taper positions (L1, L2, L3, L4) in the abutment hole were established using 3D software and five screw taper angles (30°, 60°, 90°, 120°, 180°) were set. Result Taper position significantly affects the stresses in the implant system. The 30° and 180° angles (L4 position) showed less stress than other angles. Conclusion Elevated taper position and reasonable taper angle are beneficial in reducing the stress in the implant system.

Topological interface and corner states of flexural waves in metamaterial plates with glide-symmetric holes

This study investigates the topological localization and propagation of flexural waves in metamaterial plates with perforated holes exhibiting glide symmetry. The dispersion relations of flexural waves in this mechanical system exhibit four-fold Dirac degeneracies at the M point of the Brillouin zone. By properly adjusting the rotation angles of the perforated holes, these degeneracies can be lifted up to create omnidirectional bandgaps, enabling nontrivial topological phases. Both numerical and experimental results demonstrate multiple topological states of flexural waves in the developed elastic metaplates, including dual-band helical interface states and anisotropic interface/corner states. The simple perforated metaplates with glide-symmetric holes provide novel, manufacturable platforms for the flexible manipulation of topological flexural waves, greatly facilitating potential applications such as energy harvesting and signal enhancement.

Optimization of highly sensitive three-layer photonic crystal fiber sensor based on plasmonic

In this work, a photonic crystal fiber (PCF) refractive index (RI) sensor has been designed and optimized. The RIs range covered by the sensor is from 1.38 to 1.41. The proposed optical sensor has three layers of air holes with 24, 12 and 6 holes in each layer. The geometry parameters of the proposed sensor (the radius of the air holes and the thickness of the plasmonic layer) have been optimized using the Nelder-Mead algorithm and the FEM numerical with the objective of achieving the highest sensitivity. To achieve an optimized structure with minimal sensitivity to fabrication errors, the rotation angle of the hole layers has been analyzed. The results indicate that, due to the specific geometry of the proposed structure, variations in the rotation angle and displacement of the air holes have no significant impact on the outcomes. The results also indicate that the sensor’s maximum amplitude sensitivity (AS), maximum wavelength sensitivity (WS), and figure of merit (FOM) are 10000 (RIU−1), 23000 (nm/RIU) and 131 (RIU−1) respectively. The optimized design provides high sensitivity, a wide diagnostic range for the detection of the analytes’ RIs, and the advantages of a gold plasmonic layer, ensuring high stability in biological environments. This combination results in enhanced performance of the sensor for various applications particularly in biosensing and medical fields. The designed structural geometry also eliminates the effects of tolerances in manufacturing processes which makes the proposed PCF device a very efficient sensor.

Research on the Jet Distance Enhancement Device for Blueberry Harvesting Robots Based on the Dual-Ring Model

In China, most blueberry varieties are characterized by tightly clustered fruits, which pose challenges for achieving precise and non-destructive automated harvesting. This complexity limits the design of robots for this task. Therefore, this paper proposes adding a jetting step during harvesting to separate fruit clusters and increase the operational space for mechanical claws. First, a combined approach of flow field analysis and pressure-sensitive experiments was employed to establish design criteria for the number, diameter, and inclination angle parameters of two types of nozzles: flat tip and round tip. Furthermore, fruit was introduced, and a fluid–structure coupling method was employed to calculate the deformation of fruit stems. Simultaneously, a mechanical analysis was conducted to quantify the relationship between jet characteristics and separation gaps. Simulation and pressure-sensitive experiments show that as the number of holes increases and their diameter decreases, the nozzle’s convergence becomes stronger. The greater the inclination angle of the circular nozzle holes, the more the gas diverges. The analysis of the output characteristics of the working section indicates that the 8-hole 40° round nozzle is the optimal solution. At an air compressor working pressure of 0.5 MPa, force analysis and simulation results both show that it can increase the picking space for the mechanical claw by about 5–7 mm without damaging the blueberries in the jet area. The final field experiments show that the mean distance for Type I (mature fruit) is 5.41 mm, for Type II (red fruit) is 6.42 mm, and for Type III (green fruit) is 5.43 mm. The short and curved stems of the green fruit are less effective, but the minimum distance of 4.71 mm is greater than the claw wall thickness, meeting the design requirements.

Mechanism analysis of burn-up failure for needle roller bearing at high-speed gear in manual transmission

Adequate lubrication conditions of needle roller bearings are crucial for the normal operation of transmission. Addressing the burn-up and adhesion failures of needle roller bearings during transmission bench trials, two rigid body rotation physical models were developed to analyze and model the lubrication effect on the inner and outer surfaces of needle roller bearing. Through theoretical analysis and lubrication simulation, it was found that under the critical condition of d/D=0.553, the centrifugal force F on the outer ring surface of the needle bearing was related to the density of lubricant, rotational speed, as well as the angle and size of oil hole, rather than the position of the oil holes; Moreover, the centrifugal force F on the needle roller bearing at input shaft was related to the speed of transmission gear and was also associated with the clearance size between needle roller and cage. Theoretical analysis, simulation, and experimental results have demonstrated that the lubrication performance of needle roller bearings during operation at lower rotary speed gears was inferior to that at higher speed gears, and the lubrication was also less effective when the cage clearance was narrower. Employing angled oil inlets (holes), appropriately enlarging the diameter of oil inlets (holes), and increasing the clearance width between needle roller and cage will contribute to the improvement of lubrication effect.

Thermal fluctuations, deflection angle, and greybody factor of a high-dimensional Schwarzschild black hole in scalar–tensor–vector gravity

In this study, we examined the thermal fluctuations, deflection angle, and greybody factor of a high-dimensional Schwarzschild black hole in scalar–tensor–vector gravity (STVG). We calculated some thermodynamic quantities related to the correction of the black hole entropy caused by thermal fluctuations and discussed the effect of the correction parameters on these quantities. By analyzing the changes in the corrected specific heat, we found that thermal fluctuations made the small black hole more stable. It is worth noting that the STVG parameter did not affect the thermodynamic stability of this black hole. Additionally, by utilizing the Gauss–Bonnet theorem, the deflection angle was obtained in the weak field limit, and the effects of the two parameters on the results were visualized. Finally, we calculated the bounds on the greybody factor of a massless scalar field. We observed that as the STVG parameter around the black hole increased, the weak deflection angle became larger, and more scalar particles can reach infinity. However, the spacetime dimension has the opposite effect on the STVG parameter on the weak deflection angle and greybody factor.

Geodesics structure and deflection angle of electrically charged black holes in gravity with a background Kalb–Ramond field

This article investigates the geodesic structure and deflection angle of charged black holes in the presence of a nonzero vacuum expectation value background of the Kalb–Ramond field. Topics explored include null and timelike geodesics, energy extraction by collisions, and the motion of charged particles. The photon sphere radius is calculated and plotted to examine the effects of both the black hole charge (Q) and the Lorentz-violating parameter (b) on null geodesics. The effective potential for timelike geodesics is analyzed, and second-order analytical orbits are derived. We further show that the combined effects of Lorentz-violating parameter and electric charge can mimic a Kerr black hole spin parameter up to its maximum values, i.e., a/M∼1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$a/M \\sim 1$$\\end{document} thus suggesting that the current precision of measurements of highly spinning black hole candidates may not rule out the effect of Lorentz-violating parameter. The center of mass energy of colliding particles is also considered, demonstrating a decrease with increasing Lorentz-violating parameter. Circular orbiting particles of charged particles are discovered, with the minimum radius for a stable circular orbit decreasing as both b and Q increase. Results show that this circular orbit is particularly sensitive to changes in the Lorentz-violating parameter. Additionally, a timelike particle trajectory is demonstrated as a consequence of the combined effects of parameters b and Q. Finally, the light deflection angle is analyzed using the weak field limit approach to determine the Lorentz-breaking effect, employing the Gauss–Bonnet theorem for computation. Findings are visualized with appropriate plots and thoroughly discussed.

Generated genuine tripartite steering and its monogamy in the background of a Kerr-Newman black hole* *Supported by the National Natural Science Foundation of China (12205133, LJKQZ20222315, JYTMS20231051), and the Special Fund for Basic Scientific Research of Provincial Universities in Liaoning (LS2024Q002)

We study the redistribution of quantum steering and its monogamy in the presence of a four-dimensional Kerr-Newman black hole. The gravitational effect of the Kerr-Newman black hole is shown to generate genuine tripartite steering between causally disconnected regions, depending on the polar angle, angular momentum, electric charge, and magnetic charge of the black hole. We obtain strong evidence of steering monogamy, that is, the "sudden death" of the A → B steering results in the "sudden birth" of B → B steering. We also obtain the condition of maximal steering asymmetry, that is, , revealing the transition between two-way and one-way steering in Kerr-Newman spacetime.

Design and experimental demonstration of a high-performance all-silicon transverse magnetic polarizer using tilted-elliptical-hole arrays

This study presents the design and experimental demonstration of a high-performance all-silicon transverse magnetic (TM) polarizer. The tilted-elliptical-hole arrays are designed to effectively reflect transverse electric (TE) modes while propagating TM modes with low loss. The device bandwidth (BW) is controlled by changing the tilting angle of the elliptical hole or by combining it with changes in other parameters. The device operates beyond 326 nm (1385–1711 nm) in BW, achieving an average insertion loss (IL) below 1.0 dB and a polarization extinction ratio (PER) over 20 dB. A 20 nm shift in BW can be obtained with a 30° deflection, and an 80 nm shift can be achieved with multiple parameter changes. The experimental results confirm the theoretical analysis. The present device with the advantages of simple structure, flexible design, and broad BW has great potential applications in silicon photonics.

Investigate the optimum design of atomizing nozzles for coal dust suppression by using multifactor level response surface methodology

Mechanized coal extraction generates substantial dust, adversely affecting the physical and mental wellbeing of underground workers and degrading the operational environment. To address the limitations of traditional spray systems, which often suffer from poor atomization effects and limited ability to withstand wind interference, the innovative vortex atomizing nozzle has been developed specifically for dust suppression. This advanced solution was rigorously tested through detailed numerical simulations and comprehensive experimental investigations. These studies focused on examining the impact of critical parameters, including the velocity at the airflow director's exit, the angle of the exit hole, and its radius, on the efficacy of dust suppression. Findings highlighted the paramount importance of the airflow director's exit velocity in enhancing dust removal, with the exit hole's radius having the least impact. Optimal conditions for dust suppression were identified as an airflow director exit velocity of 20 m/s, an angle of 60°, and a radius of 0.6 mm. Field validations under these optimum parameters demonstrated unparalleled dust control efficiency, achieving a reduction in coal dust concentration exceeding 90 %. This apparatus offers a highly effective, user-friendly solution for comprehensive coal dust management across various mine locations.

Optimizing diesel engine performance and emissions with diesel-hydrogen mixtures: Impact of injector configuration, angle, and pressure

Several factors affect engine performance, including fuel injection pressure, injection angle, and injector orifice diameter. Any deviation from normal conditions in any of these aspects can disrupt optimal engine performance, resulting in inefficient combustion and increased exhaust emissions. To investigate the effect of injector hole number, injection hole angle, and injection pressure on the performance and emissions of a diesel engine operating on a diesel/hydrogen blend (10 % hydrogen and 90 % diesel), a single-cylinder direct injection diesel engine was used. Three injector nozzle configurations just for diesel injector with different hole diameters (0.6, 0.3, and 0.2 mm) were used at injection angles of 0, 15, and 30 degrees, respectively. Three injection pressures (200, 400, and 600 bar) were tested, with results monitored for brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), smoke, and NOx emissions.Optimal results were achieved with a maximum injection pressure of 400 bar and a nozzle angle of 15 degrees, resulting in improved engine performance and BTE, along with a 6.5 % reduction in BSFC. Increasing the number of injector holes, injection pressure, and injection angle resulted in reduced BSFC and smoke emissions, but with a significant increase in NOx emissions. Notably, this study deviates from traditional combustion methods by introducing air from a 1.1-atmosphere tank instead of relying solely on natural intake. In addition, hydrogen fuel is introduced into the air manifold via a separate injector with an injection pressure of 20 bar, while diesel fuel is injected directly into the combustion chamber.

Effects of Dowel Rotation Welding Conditions on Connection Performance for Chinese Fir Dimension Lumbers

In this study, the rotating welding process of Chinese fir (Keteleeriafortunei) in Guizhou, China, was systematically analyzed. The effects of rotating welding conditions, including the dowel-to-guide hole diameter ratio, welding time, depth, base surface, angle, and dowel type, on the performance of welded Chinese fir were explored. Moreover, the physical and chemical changes oftheChinese fir interface during welding were revealed by Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The results indicated the following: (1) The rotating welding technology can quickly achieve a strong connection between wood through friction heat without chemical adhesives and compared with traditional wood connection technology such as gluing or mechanical fixing;it has the advantages of simple operation, high production efficiency; and environmental friendliness. (2) Aftertherotating welding, the wood underwent significant pyrolysis, especially the degradation of hemicellulose. The heat generated in the welding process caused good melting and mechanical interlocking between the dowel and the wall of the guide hole, but it was also accompanied by afriction loss of the dowel and the substrate. (3) The welding parameters affected the wood’s connection strength and stability by altering heat production, distribution, transfer, and frictional losses. The impact of the dowel-to-guide hole diameter ratio had a great influence on the connection strength. When the diameter ratio was 1:0.7, the tensile strength was the highest, reaching 2.27 MPa. (4) The analyses of XPS, FTIR, XRD, and SEM proved thatthechemical composition changes at the interface, leading to a more structured crystalline bond and enhanced connection strength due to fiber entanglement and interlocking. This research providesatheoretical and experimental basis forthefurther innovation and development of wood processing technology and provides a new technical path forthegreen manufacturing of wood structure buildings.

Conservative Black Hole Scattering at Fifth Post-Minkowskian and First Self-Force Order

We compute the fifth post-Minkowskian (5PM) order contributions to the scattering angle and impulse of classical black hole scattering in the conservative sector at first self-force order using the worldline quantum field theory formalism. This challenging four-loop computation required the use of advanced integration-by-parts and differential equation technology implemented on high-performance computing systems. Use of partial fraction identities allowed us to render the complete integrand in a fully planar form. The resulting function space is simpler than expected: In the scattering angle, we see only multiple polylogarithms up to weight three and a total absence of the elliptic integrals that appeared at 4PM order. All checks on our result, both internal—cancellation of dimensional regularization poles and preservation of the on-shell condition—and external—matching the slow-velocity limit with the post-Newtonian (PN) literature up to 5PN order and matching the tail terms to the 4PM loss of energy—are passed. Published by the American Physical Society 2024

Investigation on the Influence of Film Cooling Structure on the Flow and Heat Transfer Characteristics of Axisymmetric Plug Nozzle

Some numerical simulations were used to study the effects of blowing ratio (0.25–0.5), hole diameters(0.65~1 mm), and hole inclination angle (30~60°) of the film cooling structure on the cooling and aerodynamic characteristics of the axisymmetric plug nozzle under the condition of transonic. The results showed that the bow shocks appear near the film holes on the plug wall in the supersonic region, which cause the wall cooling effectiveness of the plug to decrease. Compared with the baseline plug, the blowing ratio ranged from 0.25 to 0.5, the wall average temperature of the rear plug decreased by 34.4~48.1%, the thrust coefficient and total pressure recovery coefficient decreased by 0.31~0.61% and 0.52~0.93%, respectively. When the perforated percentage is constant, the wall cooling effectiveness increases with the decrease of the hole diameters. The increase in the inclination angle of the film holes lead to the decrease in cooling effectiveness and aerodynamic performance. This is because the penetration ability of the cooling air to the mainstream is enhanced, and the obstruction to the mainstream boundary layer is increased, resulting in the increase of bow shock intensity near the film holes in the supersonic region.

Tunable deformation design of porous Al2O3 based on the Direct FE2 method

Abstract The tunable deformation design of porous ceramics has raised many interests in many engineering and manufacturing fields, where its corresponding design methodologies still suffer from the lower efficiency and higher computational cost. To handle this problem, a novel optimization and design methodology based on the Direct FE2 method has been proposed in this study, and several numerical examples of the porous Al2O3 tunable deformation design has been performed by this novel methodology. Compared with the traditional methodologies, the proposed method is more convenient to conduct the tunable deformation design and improves the optimization efficiency. Based on this method, the distribution and assembly of the microscale RVE could be tailored along the space dimension to handle the sinusoidal deformation and variable Poisson’s ratio ceramic design at the macroscale. By comparing the simulation results with the Direct Numerical Simulation (DNS) model, the effectiveness and accuracy of this methodology is well validated. Meanwhile, the simulation results based on the proposed methodology found that the predictability of porous Al2O3 deformation could be enhanced by changing the micro structure parameters such as the elliptical hole angle and aspect ratio. This methodology holds great potential for applications in the design and optimization of porous ceramics with tailored deformation characteristics.