Hole Diameter Research Articles

Visible Light-Illuminated Gold Nanohole Arrays With Tunable On-Chip Plasmonic Sensing Properties

Since the discovery of the extraordinary optical transmission phenomenon, nanohole arrays have attracted much attention and been widely applied in sensing. However, their typical fabrication process, utilizing photolithographic top-down manufacturing technologies, has intrinsic drawbacks including the high costs, time consumption, small footprint, and low throughput. This study presented a low-cost, high-throughput, and scalable method for fabricating centimeter-scale (1×2 cm2) nanohole arrays using the improved nanosphere lithography. The large-scale close-packed polystyrene monolayers obtained by the hemispherical-depression-assisted self-assembly method were employed as colloidal masks for the nanosphere lithography, and the nanohole diameter was tuned from 233 nm to 346 nm with a fixed period of 420 nm via plasma etching. The optical properties and sensing performance of the nanohole arrays were investigated, and two transmission dips were observed due to the resonant coupling of plasmonic modes. Both dips were found to be sensitive to the surrounding environment, and the maximum bulk refractive index sensitivity was up to 162.1 nm/RIU with a 233 nm hole diameter. This study offered a promising approach for fabricating large-scale highly ordered nanohole arrays with various periods and nanohole diameters that could be used for the development of low-cost and high-throughput on-chip plasmonic sensors.

Shaking a container full of perfect liquid; a tractable case, a torus shell, exhibits a virtual wall

Manipulation (‘shaking’) of a rigid container filled with incompressible liquid starting from stationary generally results in some displacement, or mixing, of the liquid within it. If the liquid also has zero viscosity, a ‘perfect’ or ‘Euler’ liquid, Kelvin’s theorems dramatically simplify the flow analysis. Response is instantaneous; stop the container and all liquid motion stops. In fact an arbitrary manipulation can be considered as alternating infinitesimal translations and rotations of the container. Relative to the container, the liquid is stationary during every translation. Infinitesimal rotations (an infinitesimal vector along the rotation axis) resolve into three orthogonal components in the container frame. Each generates its own infinitesimal liquid displacement vector field. Their combined consequences are usually obscure. Rather than a volume flow, a surface flow in 3D is considerably easier, the liquid slipping freely in a shell, sandwiched between two nested closed surfaces with constant infinitesimal gap. The closedness avoids extra boundaries. The two dimensionality admits a scalar streamfunction determined by the container angular velocity vector. Manipulation of the container angular velocity at will, usually leads to an infinitely rich variety of area preserving re-configurations of the liquid. In particular, any chosen point of the liquid can be moved, in the shell container frame, to any other chosen point. However, for a torus (shell) with a small enough hole (diameter < 0.195 torus diameter), there exists a virtual wall, a hypothetical axial cylinder intersecting the torus. No matter how the torus is manipulated, liquid inside the cylinder stays inside; outside stays outside. The analysis, solving for the streamfunction, is based on the relative vorticity, and the conformal mapping of a torus to a (periodic) rectangle, which lead to a fairly simple convolution integral formula for the flow.

A novel Zende’s-TOPSIS method towards estimation of measurement uncertainty in hole diameters

The ‘Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS)’ is one of the best methods for ‘Multi-Criteria Decision-Making’ and ‘Multi-Objective Optimization’. The traditional TOPSIS method determines the best alternative under fixed conditions. However, it cannot determine the best upper limit and lowest limit values. This work explains the detailed methodology of the newly developed Zende’s-TOPSIS method which was used to estimate the measurement uncertainty in hole diameters. Four identical holes and one center hole in an industrial component were measured to investigate measurement uncertainty. According to the experimental results, Zende’s-TOPSIS method performed better than the traditional TOPSIS method. The percentage improvement in the Zende’s-TOPSIS method over the traditional TOPSIS method ranges from 0.0209% to 0.3053%. Using Zende’s-TOPSIS method, the percentage maximum measurement uncertainty for four identical holes varies from 0.8067% to 1.0222%, whereas for the center hole, it varies from 0.5261% to 0.5576%. Similarly, the percentage minimum measurement uncertainty for four identical holes varies from 0.3839% to 0.6406%, whereas for the center hole, it varies from 0.4014% to 0.4041%. The proposed method is also capable of estimating the machined tolerances of the component, which ranges from 18.0772 mm to 18.1708 mm for four identical holes and 49.2215 mm to 49.2572 mm for the center hole. The proposed method can solve various ‘Multi-Objective Optimization’ problems.

Study of Vector Bending Sensor in Various Configurations

A triple-core photonic crystal fiber (TCPCF) vector bending sensor has been introduced to study geometric parameter changes. The TCPCF shows a linear relationship between effective refractive index and input wavelength near 1.55µm. An asymmetrical geometry has been proposed for sensing both the direction and amplitude of the bend. The geometry of fiber creates an asymmetrical refractive index profile that leads to shifts in light speed in different fiber sections during the bend. The finite element method is used to study all sensor structures. The variation of the distance between cores, air hole diameter, and the angle between the side cores are studied. This sensor's need for precise and complex fabrication techniques is one of their challenges. Another challenge the design of these types of sensors faces is calibration for different environments and fabrication methods after fabrication is finished.

Action Mechanism of Film Extraction on Channel Impingement Cooling for Blade Leading Edge Using Large Eddy Simulation

Abstract Various internal cooling techniques combined with external film cooling are applied to cool gas turbine blades, and the coolant extraction can cause variations in internal flow structures and cooling effectiveness. Effects of film extraction under different film hole diameters and coolant mass flow ratio on heat transfer and flow characteristics of channel impingement cooling are presented using large eddy simulation (LES) in this article. The current work was undertaken based on turbine blade dimensions and turbine operating conditions. The results indicate that film extraction coupled with the curvature-induced instability dominates flow patterns and heat transfer in the channel impingement cooling structure with a film hole, especially in the bend region corresponding to the leading edge of turbine blades. Film coolant extraction can disrupt the streamwise counterrotating flow circulation pair. The latter is caused by the curvature-induced instability and is also the major driver of multilongitudinal vortices. The hole edge vortex generated by coolant bleed amplifies heat transfer at the leading edge, and the effect is more significant as the film hole diameter increases. Conversely, heat transfer coefficient downstream of the cooling channel decreases due to a reduction in cooling air. The increasing film bleed flow increases overall total pressure loss, while flow loss in the cooling channel decreases because of the weakened flow circulations and reduced coolant mass flow. This work provides an in-depth insight into the cooling performance of channel impingement cooling with film extraction, contributing to designing film cooling for turbine blades with multichannel wall jet cooling.

Influence of Structural Parameters of Gearbox Seal System of Electrical Multiple Units on Seal Performance

The gearbox seal system is a critical component of the electrical multiple units drive system, with a direct impact on the safety and reliability of train operations. This study intends to analyze how structural parameters of the gearbox seal system influence the seal performance from the viewpoint of “oil–air separation and scavenge oil” by using a discrete phase model and volume of fluid. The results show that the oil–air separation performance is mainly affected by the oil droplets’ inertia force and the airflow traction force, and the scavenge oil performance is decided by the oil–air separation performance of each seal chamber. The relationships between seal chamber size, axial seal clearance width, height difference, scavenge oil hole diameter, and seal performance are analyzed, and the study also found that optimizing the stator chamber depth–width ratio of the seal system studied in this paper at 2.5, reducing the rotor chamber depth–width ratio and axial seal clearance width, and increasing the relative height difference can improve the seal performance. And increasing the scavenge oil hole diameter also enhances the seal system’s performance. The simulation results can be used as design references for gearbox seal systems.

Experimental Investigation of Flow Drilling and Flow Tapping of Thin-Walled Square and Circular Hollow Sections

One of the most important problems of automotive engineering is joining metal sheets, thin-walled tubes or profiles simply, efficiently, and economically. After conventional drilling and tapping in thin-walled materials, the strength remains low due to the small number of teeth and the connection can be easily unfastened. For increasing the strength there are several solutions such as using welded nuts, tapped rivets and welding extra nuts. Since nut welding cannot be done on the inner surfaces, these solutions are inadequate for square and circular tubes. In this study, holes of various diameters were drilled on 1.5 mm thick AISI 304 stainless steel and EN AW-6060 square and circular profiles by flow drilling at various rotational speeds, and then flow tapping was applied to the holes. The same processes were repeated with conventional drilling method to compare bushing heights and clamping strengths of the parts as well as the hardness values and capillary crack formations around the holes. According to the results obtained, the strength in flow drilling and tapping increases by 50-55% compared to the classical drilling method. The reason for this is that as the hole diameter increases, the amount of material plastered and the number of threads required for screwing increases approximately 2.5-3 times. Capillary cracks, which are observed in holes drilled with the traditional method as the hole diameter increases, are not observed with this method and thus increasing the strength of the connection.

Innovative Heat Transfer Enhancement in Tubular Heat Exchanger: An Experimental Investigation with Minijet Impingement

Innovative Heat Transfer Enhancement in Tubular Heat Exchanger: An Experimental Investigation with Minijet Impingement

Prospective Evaluation of Results of Surgical Treatment of Patients with Idiopathic Macular Hole by Phacovitrectomy and Combined Cataract and Vitrectomy Surgery

Purpose of the study:The purpose of the study was to compare the morphological and functional results of the studied patients with idiopathic macular hole treated with a one-stage method (phacovitrectomy) and combined cataract and vitrectomy surgery.Material and methods:The study included 33 patients (33 eyes) with idiopathic macular hole treated at the Department of Retina and Vitreous Surgery in Lublin. Twenty-one eyes were surgically treated with phacovitrectomy (Group 1 MH). Twelve patients underwent two-stage, combined treatment with removal of the lens in the first stage and vitrectomy in the second (Group 2 MH). The assignment of patients to groups was random. All patients underwent 23-gauge sutureless vitrectomy with removal of the internal limiting membrane (internal limiting membrane peeling). SF6 gas was used as an intraocular tamponade at an isovolumetric concentration of 20% and face down position recommendation for 7 days. Cataract surgery was performed using the phacoemulsification method with an incision in the transparent part of the cornea with intracapsular, posterior chamber implantation of a monofocal lens. A 12-month observation period was established, measured from the date of vitrectomy performance, and in the case of a combined procedure, this period was extended by the time between each stage of treatment. At subsequent check-ups, the subjects underwent a complete ophthalmological examination, which included: best corrected distance visual acuity and best corrected near visual acuity, assessment of the anterior and posterior segments, in a slit lamp, measurement of retinal sensitivity in the macula using microperimetry, the Amsler test and optical coherence tomography examination of the macula.Results:In patients of the total studied group, an improvement in the best-corrected visual distance and near acuity was obtained, and in 88% retinal sensitivity in the macula was also achieved. In the group of patients subjected to phacovitrectomy (Group 1 macular hole) with an average minimum hole diameter of 487.48 µm before the procedure, after a one-year follow-up the mean best corrected distance visual acuity was 0.57 and best corrected near visual acuity 0.51, with macular retinal sensitivity of 26.65 dB. However, in the group of patients subjected to combined cataract and vitrectomy, an average minimum hole diameter of 521.58 µm 12 months after trans pars plana vitrectomy was performed as well as an average best corrected distance visual acuity of 0.64, best corrected near visual acuity of 0.5, and retinal sensitivity in the macula of 25.98 dB. There were no statistically significant differences between phacovitrectomy and the combined procedures in terms of the improvement in the values of distance and near visual acuity and macular retinal sensitivity 12 months after trans pars plana vitrectomy. A statistically significant improvement in retinal sensitivity in the macula was observed in Group 1 macular hole during the 12-month follow-up, while in the combined procedure group the improvement was not statistically significant.Conclusions:Vitrectomy is an effective method of treating maculopathy in the form of macular hole. Morphological and functional improvement was noted in all patients, regardless of the treatment method used. There were no statistically significant differences between phacovitrectomy and the combined procedure in terms of the improvement achieved in the values of distance visual acuity parameters, near vision and retinal sensitivity in the macula 12 months after trans pars plana vitrectomy. A common feature of patients with worse results on individual variables was a longer duration of the disease and a larger size of the hole prior vitrectomy.

Stepwise Flux Density Amplification of Coil Stacked by HTS Plates With Different Diameter Holes

Stepwise Flux Density Amplification of Coil Stacked by HTS Plates With Different Diameter Holes

An investigation on the jet formation and penetration characteristics of the CuCoCrFeNi high-entropy alloy liner

This study performs a series of mechanical tests, quasi-static and dynamic, on CuCoCrFeNi high-entropy alloys (HEAs) using an experimental setup to explore the performance of Cu-based HEAs in shaped charges. It derives the parameters for the Johnson–Cook constitutive model through fitting. A static penetration test is conducted with a small cone angle and a thin-walled liner. The outcomes are then compared to simulation data generated by AUTODYN software. They indicated that the CuCoCrFeNi HEA liner can produce a shaped-charge jet that achieves both penetration and reaming effects when driven by explosives. In a C45 steel target, the diameter of the penetration hole is 46.43% of the charge diameter. The experimental findings align closely with the simulations, indicating discrepancies of less than 12.13% in the diameters of the penetration holes and ∼2.56% in penetration depths. Hence, the numerical simulation approach and its parameters can be utilized to investigate the penetration characteristics of Cu-based HEA jets, providing a groundwork for future optimization of HEA-shaped charge designs.

Impact radius of light oil pipeline leakage under different operating conditions

This study investigated the impact range of pipeline leaks for light oil pipelines under different operating conditions. Three different calculation methods were employed to study the influence of various factors, including obstacle height, wind speed, leak hole diameter, and slope, on the leak impact range of flowing fires, pool fires, and overpressure waves. The results indicate that the impact range decreases as the height of obstacles increases. The most significant decrease occurs when obstacles are 2 meters high, and further increasing the obstacle height leads to a less pronounced decrease. Wind speed has a complex influence on the impact range. For flowing fires, the impact range initially increases and then decreases with higher wind speeds. For pool fires, a higher wind speed leads to a larger impact range, while for overpressure waves, higher wind speeds result in a smaller impact range. Larger leak hole diameters lead to larger impact ranges for both fire radiation and overpressure waves. Increasing the environmental slope has a slight effect on the impact range. Sensitivity analysis indicates that wind speed has the most significant impact, followed by leak hole diameter, while the environmental slope has the least influence on the impact range.

Estimation of Surge and Swab Pressures While Tripping for Minimizing Excessive Drilling Problems

Surge and swab pressures result from pipe movement upward/downward during drill string reciprocation and tripping. surge and swab create costly drilling concerns such well kick, formation breakage, and lost circulation. This study aims to find the optimum pipe tripping speed to avoid surge and swab issues, particularly in lost circulation zones. Also, to determine how drilling factors and well bore geometry affect surge and swab pressures. Mud rheology, mud properties, hole diameters, drill pipe diameter, and bottom hole assembly (BHA) dimensions were also analyzed. Dynamic surge and swab model was employed to simulate two case studies in Rumaila Iraqi oilfield. The findings indicated that the tripping speed is the most effective variable on surge and swab pressures. Annular clearance and BHA design have also a major effect on the surge and swab pressures. For the first case study, it is found that whenever the mud weight is far from the pore pressure and fracture pressure gradients, the 5" drill pipe can be tripped in/out of lost circulation formation (Shuaibba formation) at optimum tripping speed of (80 ft/min) without surge/ swab related problems. The reason is that the generated surge pressures (6110-6300 psi) are below the fracture pressure (7100-7400 psi). The results also showed that tripping 5" drill pipe within a maximum running speed of 80 ft/min in (8.5") open hole section through Tanuma formation till Rumaila formation causes a surge pressures of (4650-5050 psi) which is still below the fracture pressures of formations (4750-5660 psi). the results of the second case study (S-shaped well) revealed that the optimum tripping speed of the drill string in the (12.25") open hole through Dammam and Hartha formations is (90 ft/min). it is also concluded that pulling out of hole (POOH) process must be carried out more carefully than the running process since the mud density is near the pore pressure gradient. The results of this study can be further used to improve the drilling efficiency in Rumaila oil field with decreasing non-productive time (NPT) by employing the appropriate tripping speed and optimal drilling operations.

Effect of Layers on Delamination and Tensile Strength of Woven Fiber Composites with Polyester Matrix

A composite is a combination of 2 or more different materials. The composite joining process can use adhesives or mechanically by making holes. During the process of making holes in the composite, it can cause delamination in the composite. Delamination and layer thickness greatly influence the strength of hollow composite joints. This research aims to determine the effect of delamination factors and the number of layers on the tensile strength value of the composite. The materials used in this research are polyester resin and woven glass fiber. The method used is vacuum bagging with variations in the number of layers, namely 3 layers, 4 layers, 5 layers, and 6 layers. Tensile testing refers to ASTM D638 standards. Specimens that have been cut according to standards will then be perforated in the center with a hole diameter of 4 mm using a milling machine. The highest tensile strength value was obtained in the 6-layer variation of 237.448 MPa and the lowest value was obtained in the 3-layer variation of 186.221 MPa. The delamination value greatly influences the tensile strength of the composite, where the more layers, the delamination value will decrease and increase the tensile strength of the composite.

First report of Bretziella fagacearum infecting chestnut in Michigan.

In the summer of 2021, a 20-year-old 'Colossal' (Castanea sativa × C. crenata hybrid) tree in a commercial chestnut orchard in northwest Michigan suddenly declined. Until 2023, an additional 26 adjacent trees declined, suggesting the occurrence of root-graft transmission of the pathogen. The initial wilting of leaves progressed to complete tree death in about 10 days. Symptoms included wilting, and bronzing, followed by tanning starting at leaf apex and margins, with significant defoliation. Sometimes black-to-brown streaks of discoloration appear in the sapwood, with no signs of mycelial mat production on dead trees. Branches from symptomatic trees in two different areas of the orchard were submitted to Plant and Pest Diagnostics at Michigan State University. Bretziella fagacearum (Bretz) Z.W. de Beer, Marinc., T.A. Duong & M.J. Wingf. was detected in both samples using nested PCR (Wu et al. 2011) and qPCR (Bourgault et al. 2022). The products of the nested PCR were sequenced (GenBank accession nos. OR522695-OR522696) and BLASTn search results showed 100% identity to an ex-type strain of B. fagacearum (MH865866). Surface-sterilized discolored sapwood chips were plated on acidified potato dextrose agar (aPDA). Bretziella fagacearum was consistently recovered; colony and endoconidia morphology aligned with the description of the pathogen (De Beer et al. 2017). A pure culture (BF277) was obtained for inoculation experiments. To confirm pathogenicity, 10 'Colossal' chestnut seedlings (average stem diameter of 9 mm) were inoculated in the greenhouse with a 14-day old culture of BF277. Using a conical drill bit, two 0.4 mm diameter holes were drilled, one was 5 cm above the soil line at a 45° angle and the other was on the opposite side of the stem at least 10 cm above the soil line. A 50-µl conidial suspension (1 × 107 conidia per ml) was applied and the holes were sealed with Parafilm. Five 'Colossal' seedlings were inoculated with sterile water. Leaf epinasty with bent petioles was observed 14 days later. Leaf wilting and necrosis similar to natural infection in the orchard were observed at 24 and 34 days after inoculation, respectively. Water-inoculated control plants showed no symptoms. Bretziella fagacearum was reisolated from symptomatic plants by surface sterilizing leaf petioles with 75% ethanol (30 s), followed by 10% (v/v) bleach (1 min), and two rinses with sterile deionized water (>1 min). Petiole pieces (~1 cm) were plated on aPDA. The pathogen was reisolated from six symptomatic plants and detected using qPCR in the remaining four seedlings. Bretziella fagacearum was not detected in control plants. The identity of the recovered fungus was confirmed following the amplification of the internal transcribed spacer (ITS) from extracted genomic DNA, as described in Chahal et al. 2022. The resulting PCR product was sequenced and assembled into a consensus sequence using Geneious Prime. The consensus sequence (accession no. OR515809) revealed 100% identity to the ex-type of B. fagacearum (KU042044). This is the first record of B. fagacearum infecting chestnut trees in Michigan. Previously, B. fagacearum has been reported infecting Chinese chestnut (C. mollissima) in Missouri (Bretz and Long, 1950). Oak wilt is widely distributed in Michigan and is the predominant disease afflicting red oaks in the Midwestern U.S. Consequently, constant vigilance and monitoring are essential in chestnut orchards to promptly detect and effectively manage potential infections.

Study on thermal penetration process of oil casing in shallow water environment by plasma arc based on heat source simulation and experiments

Abandoned offshore oil wellheads must be removed and plugged to protect the marine environment. Underwater plasma arc cutting holds the promise of playing a significant role in this work. However, much remains unknown about the thermal burn-off process of underwater plasma arcs for oil well casing. This work investigated the thermal penetration process of oil casing in a shallow water environment through experiments and heat source modeling simulations. A workpiece made of mild steel plate and cement block was considered as a small segment of the oil casing to be penetrated. The hole diameters, depths, and removal volumes of the workpieces were investigated experimentally. A combined heat source consisting of an elliptical cone heat source and a semi-ellipsoidal heat source was established based on the hole shape. The simulated and experimental hole profiles matched well. The results showed that the evolution of the hole shape of the workpiece was related to the motion state of the plasma arc and could be reflected by the variation of the arc voltage. Compared to steel plates, cement materials were easily removed by heat. These findings are favorable to promote the development of underwater plasma arc cutting in oil casing removal.

Enhancing rock fragmentation assessment in mine blasting through machine learning algorithms: a practical approach

The optimization of blasting operations greatly benefits from the prediction of rock fragmentation. The main factors that affect fragmentation are rock mass characteristics, blast geometry, and explosive properties. This paper is a step towards the implementation of machine learning and deep learning algorithms for predicting the extent of fragmentation (in percentage) in open pit mining. While various parameters can affect rock fragmentation, this study considers ten among them (i.e., spacing, drill hole diameter, burden, average bench height, powder factor, number of holes, charge per delay, uniaxial compressive strength, specific drilling, and stemming) to train and test the models. However, due to a weak correlation with rock fragmentation, drill diameter, average bench height, compressive strength, stemming, and charge per delay are eliminated to reduce model complexity. A total of 219 data sets having five input features including the number of holes, spacing, burden, specific drilling, and powder factor are used to develop the models. Machine learning models (random forest regression, support vector regression, and XG boost), as well as a deep learning model (neural network regression), are applied to develop a practical way that can optimize the prediction of fragmentation. This study employs performance measures such as R-squared, RMSE, MSE, MAPE, and MAE. The optimization of the model revealed promising results, indicating that the architecture 5-64-32-16-1 exhibits strong performance. Specifically, the model achieved mean squared error (MSE) values of 41.32 and 28.59 on the training and test datasets, respectively. The R2 value for both training and test is 0.83. RFR is also performing well compared to SVR and XG boost with MSE values of 12.37 and 9.89 on training and testing data, respectively.in both sets, the R2 value is 94%. Based on permutation importance and shapely plot values, it is observed that the powder factor has the highest impact, while the burden has the lowest impact on fragmentation.

An Experimental Study on the Large-Volume Liquid Hydrogen Release in an Open Space

Liquid hydrogen is one of the high-quality energy carriers, but a large leak of liquid hydrogen can pose significant safety risks. Understanding its diffusion law after accidental leakage is an important issue for the safe utilization of hydrogen energy. In this paper, a series of open-space large-volume liquid hydrogen release experiments are performed to observe the evolution of visible clouds during the release, and an array of hydrogen concentration sensors is set up to monitor the fluctuation in hydrogen concentration at different locations. Based on the experimental conditions, the diffusion of hydrogen clouds in the atmosphere under different release hole diameters and different ground materials is compared. The results show that with the release of liquid hydrogen, the white visible cloud formed by air condensation or solidification is generated rapidly and spread widely, and the visible cloud is most obvious near the ground. With the termination of liquid hydrogen release, solid air is deposited on the ground, and the visible clouds gradually shrink from the far field to the release source. Hydrogen concentration fluctuations in the far field in the case of the cobblestone ground are more dependent on spontaneous diffusion by the hydrogen concentration gradient. In addition, compared with the concrete ground, the cobblestone ground has greater resistance to liquid hydrogen extension; the diffusion of hydrogen clouds to the far field lags. The rapid increase stage of hydrogen concentration at N8 in Test 7 lags about 3 s behind N12 in Test 6, N3 lags about 7.5 s behind N1, and N16 lags about 8.25 s behind N14. The near-source space is prone to high-concentration hydrogen clouds. The duration of the high-concentration hydrogen cloud at N12 is about 15 s, which is twice as long as the duration at N8, increasing the safety risk of the near-source space.

Study of the tensile mechanical properties and failure mechanisms of CFRP screwed joints

Removable joint technology is commonly used in composite laminates for various load-bearing structures. However, existing research primarily focuses on bolted joints, there is relatively limited research on screwed joints in composite materials. This study investigates the influence of connected layer thickness and hole diameter on the tensile behavior of threaded joints in carbon fiber-reinforced polymer (CFRP) laminates. After fabricating different CFRP screwed joint specimens, tensile tests were conducted. The digital image correlation (DIC) technique captured the deformation process. The experiment results indicate a significant increase in load-bearing capacity with the increase in diameter. For instance, joints with an 8 mm diameter exhibited a load-bearing capacity of 10.82 kN. The increase in the connected layer thickness correspondingly enhanced the load-bearing capacity of the joint. The joint with a thickness of 7 mm had the highest load-bearing capacity of 8.83 kN. Besides, with the increase in the thickness of the connected layer, the failure mode transitioned from shear failure in the connected layer to screw pull-out. The tilt angle of the screw during the pull-out process also decreases with the increase in the connected layer thickness. Strain and out-of-plane displacement measurements under ultimate load conditions verify these observations.

A NOVEL SURGICAL TECHNIQUE FOR GIANT AND REFRACTORY MACULAR HOLES: AUTOLOGOUS TENON CAPSULE PLUG

Purpose: To evaluate the safety and efficiency of the autologous Tenon capsule plug (ATCP) technique for the treatment of large (1000 um&lt;) and refractory macular holes (MHs). Methods: This retrospective, interventional, case series included 3 patients who underwent 23-gauge vitrectomy and ATCP technique for giant or refractory MH. All patients underwent a complete ophthalmic examination including optical coherence tomography (OCT), OCT angiography (OCTA), and microperimetry (MP). The changes in retinal structure and function were evaluated. Results: The minimum follow-up was 6 months. The preoperative minimum hole diameters were 728 um, 422 um, and 1154 um for case 1, case 2, and case 3 respectively. Case 1 and case 2 had an idiopathic MH that failed to close after vitrectomy with (internal limiting membrane) ILM peeling, whereas case 3, who had a giant, irregular MH underwent the ATCP technique as the primary intervention. Complete hole closure was achieved in all patients at the last follow-up. However, case 1 required a second ATCP surgery due to dislodgement of the plug in the early postoperative period. The BCVA increased in all patients. The final MP analysis revealed that the percentage of fixation points at circles 4o for case 1, case 2 and case 3 were 93.5%, 99.9% and 95.6% respectively. Conclusions: We suggest that the ATCP technique can provide a simple, cheap, repeatable, and readily available surgical solution for the treatment of giant and refractory macular holes. Further prospective studies with a larger sample size are needed to confirm our preliminary results.