Opening Diameter Research Articles

Web crippling investigation of perforated aluminium lipped channels under interior-one-flange loading condition

This study investigates the web crippling performance of roll-formed aluminium-lipped channels (ALCs) made of 5052-H36 aluminium alloy. The influence of web perforations on the crippling resistance of webs subjected to Interior-One-Flange (IOF) loading was examined. Laboratory tests were conducted on ALCs with and without circular openings at the mid-depth of the web. Finite element (FE) models were then developed and validated against the experimental results, ensuring their accuracy. To explore the influence of various parameters on the web crippling resistance, a parametric study was carried out. The parameters considered in the study include opening diameter, section depth, inside bent radius, bearing length, and aluminium grade. Using the data obtained from the parametric study, a comprehensive assessment of the available design guidelines for cold-formed steel and stainless steel was performed. New equations in the form of reduction factors were developed to accurately predict the reduction in the web crippling strength, showing their applicability to predict the reduction in the web crippling resistance due to web openings and statistically verifying their reliability.

Perforated plate ventilation system and dynamics of infectious respiratory particle transmission

AbstractWith the removal of indoor pollutants and the assurance of air quality emerging as critical research topics, the optimization of the internal environment in offices, where people stay for extended periods, is essential for controlling the spread of infectious respiratory particles. Frequent movements of personnel and the operation of doors and windows within offices significantly impact the mechanisms of droplet transmission, warranting further investigation. This study employs computational fluid dynamics simulations to explore the droplet dispersion characteristics and pollutant removal efficiency of the simplified model of perforated plate ventilation system (PPVS) (the diameter of the air supply openings has been reasonably simplified and uniformly set to 0.02 m) in office settings, as well as the impact of dynamic door operation scenarios on droplet spread and concentrations in breathing zones. To optimize the ventilation system's pollutant removal efficiency, airflow velocities (2.86, 3.18, and 5.00 m/s) are varied, with simulations conducted at the optimal velocity of 3.18 m/s. The effects of continuous door operations, door‐opening directions (towards the office and towards the isolation room), and opening speeds (π/4, π/6, π/8, and π/10 rad/s) are also examined, revealing significant impacts on droplet spread. Results indicate that PPVS effectively reduces indoor pollutant concentrations at all tested airflow velocities, with the optimal speed identified as 3.18 m/s. Additionally, door‐opening direction and speed can significantly influence droplet spread. Opening doors towards isolation rooms at smaller angles (less than 30°) effectively reduces droplet concentrations in personnel breathing zones, thereby mitigating the risk of droplet transmission. Faster door‐opening speeds also contribute to lower droplet concentrations in these zones. This innovative study explores the impacts of PPVS and dynamic door operation dynamics on droplet transmission during respiratory disease outbreaks, providing valuable theoretical insights and technical support for disease prevention and indoor air quality improvement.

High-Throughput Spectroscopy of Geometry-Tunable Arrays of Axial InGaAs Nanowire Heterostructures with Twin-Induced Carrier Confinement.

Predicting the optical properties of large-scale ensembles of luminescent nanowire arrays that host active quantum heterostructures is of paramount interest for on-chip integrated photonic and quantum photonic devices. However, this has remained challenging due to the vast geometrical parameter space and variations at the single object level. Here, we demonstrate high-throughput spectroscopy on 16800 individual InGaAs quantum heterostructures grown by site-selective epitaxy on silicon, with varying geometrical parameters to assess uniformity/yield in luminescence efficiency, and emission energy trends. The luminescence uniformity/yield enhances significantly at prepatterned array mask opening diameters (d0) greater than 50 nm. Additionally, the emission energy exhibits anomalous behavior with respect to d0, which is notably attributed to rotational twinning within the InGaAs region, inducing significant energy shifts due to quantum confinement effects. These findings provide useful insights for mapping and optimizing the interdependencies between geometrical parameters and electronic/optical properties of widely tunable sets of quantum nanowire heterostructures.

Study on the influence of heave plate on energy capture performance of central pipe oscillating water column wave energy converter

This paper proposes a novel central pipe oscillating water column (OWC) wave energy converter (WEC) with a heave plate and investigates the influence of heave plate on energy capture performance of the OWC WEC through numerical methods. First, dynamic equations are established for floater and water column. Then, energy capture performance of the WEC is computed by solving relative motion equations using numerical methods. Wave tank experiments are conducted to validate the proposed numerical models. Finally, the influences of heave plate opening diameter and connecting column length on energy capture performance are investigated based on the proposed numerical models. The results indicate that increasing heave plate opening diameter decreases both the maximum capture width ratio (CWR) and response period. And increasing connecting column length widens the response bandwidth. When the heave plate opening diameter decreases from 350 mm to 0, the maximum CWR increases from 30.05% to 41.68% and the response period increases from 1.28 s to 1.72 s. When the connecting column length increases from 225 mm to 600 mm, the response band extends by 0.1 s. The proposed device and the obtained analysis results are of great significance for broadband and efficient wave energy generation.

A COMPARISON OF SHEAR STRENGTH CALCULATION METHODS FOR PERFOBOND LEISTE SHEAR CONNECTORS USING THE CONTROLLED VARIABLE METHOD

This paper provides a brief overview of the current research on timber-concrete composite beams and PBL shear connectors. Five representative calculation formulas were selected, and the effects of concrete strength and opening diameter on the ultimate bearing capacity of shear connectors were compared and analyzed using the controlled variable method. This study can serve as the basis for further optimizing the design parameters of composite beams.

3D Transesophageal Echocardiography in the Selection of Occluder Size for Left Atrial Appendage Occlusion: A Meta-Analysis

Background: Left atrial appendage occlusion (LAAO) can effectively reduce the risk of stroke in atrial fibrillation (AF) patients. However, the structure of left atrial appendage (LAA) varies greatly among individuals, and the size of the occluder influences the surgical success rate and prognosis. This study used a meta-analysis to investigate whether three dimensional-transesophageal echocardiography (3D-TEE) can prompt physicians to select the appropriate size of the occluder, thereby improving prognosis in patients with LAAO. Methods: Studies on 3D-TEE-assisted selection of occluder sizes in the treatment of LAAO were searched in pubmed, cochrane, Web of Science, CNKI, Wanfang, and Weipu public databases from the inception of each database to June 10, 2024. The QUADAS-2 tool was used to assess the quality of the studies. Results: 10 studies published between 2016 and 2024 were finally included, with a total sample size of 552 cases. The maximum opening of the LAA obtained by 3D-TEE, coronary angiography (CAG) and video-assisted thoracic surgery (VATS) significantly correlated with the size of the occluder (p < 0.05). 3D-TEE was superior to 2D-TEE in measuring the maximum (p = 0.04) and minimum diameters (p = 0.01) of LAA openings, and to DSA in measuring depth (p = 0.01). Conclusion: 3D-TEE can be applied to obtain LAA opening data close to the size of the occluder with minimal side effects and to assist physicians in selecting the appropriate occluder.

Design and development of lignin nanobottles: Toward developing novel multifunctional nanocomposites

The design of lignin nanostructures, which leverages interfacial interactions to enhance colloidal network entanglement, holds promise for expanding their applications in polyvinyl alcohol (PVA) composites. Herein, a novel approach is proposed for fabricating lignin nanobottles (LNBs) using biomass-derived γ-butyrolactone (GBL) to create hollow interiors connected to a single surface opening. The resulting LNBs exhibit uniform sizes of approximately 108 nm with an opening diameter of 34.94 nm. Incorporating LNBs into PVA composites enhances mechanical properties significantly, with a tensile strength of 64.96 MPa and an elongation at break of 611.6 %. Moreover, the nanocomposite films demonstrate notable antibacterial effects, UV protection, and hydrophobicity. Introducing LNBs improves photothermal conversion capacity, achieving a temperature of 62.1 °C in just 150 s. Furthermore, a meticulously designed 3D solar evaporator demonstrates remarkable evaporation performance, achieving a rate of up to 1.89 kg m-2h−1 with an outstanding efficiency of 96.55 %. When exposed to 1 sunlight, the thermoelectric material generates an output voltage of 0.83 V, indicating considerable potential for energy generation. Overall, Incorporating LNBs enhances lignin’s effectiveness in materials and provides a novel approach to augment lignin’s photothermal properties, enabling broader applications in solar-driven evaporation and thermoelectric materials.

The staining results of early gastric cancer by indigo carmine chromoendoscopy associated with histological structure: a retrospective study

BackgroundAt present, conventional endoscopy and chromoendoscopy using indigo carmine (IC) is a very useful method to determine the demarcation line (DL) of early gastric cancer lesions, but it is not suitable for all lesions.AimsThis study aimed to determine the applicable conditions for IC chromoendoscopy.MethodsWe retrospectively evaluated 187 lesions in 181 patients who had an endoscopic diagnosis of EGC and were treated with endoscopic submucosal dissection (ESD). According to the existence of the DL between the lesion mucosa and normal mucosa with IC chromoendoscopy, the lesions were divided into two groups: clear group and unclear group. Clinicopathological characteristics were evaluated in each group. From January 2022 to March 2023, the postoperative pathological sections of 19 lesions (81 slices) in the clear group and 19 lesions (80 slices) in unclear group were scanned with high definition, and the crypt structure between the two groups was evaluated.ResultsThere was no significant difference in clinical factors between the clear group and unclear group. There were significant differences in crypt area, crypt length, and crypt opening diameter between the two groups. In the clear group, there were significant differences in crypt area, crypt length, and crypt opening diameter between the normal area and cancer area, but there was no significant difference in the unclear group.ConclusionsThe margins of lesions with fused or absent crypt structures, a small crypt area, a short crypt length, and a short crypt opening diameter can be easily determined with IC chromoendoscopy.

Forming quality and static properties of self-piercing riveted joints of hot-rolled steel and aluminum alloy sheets

The self-piercing riveting (SPR) Forming and tensile tests of hot-rolled steel sheet BR1200HS and aluminum alloy sheet AA 6082-T6 were simulated by Simufact Forming software. The test results show that the diameter of the rivet leg opening, which is the most important parameter affecting the mechanical properties of the joints, shows a first increase and a second decrease with the increase of rivet length, and the Max. tensile loads of the joints have the same variation law. The larger the diameter of the rivet leg opening, the greater the Max. tensile load of the joint, and the greater the effective plastic strain of the rivet of the joint. The rivet length of the joints in the five preferred SPR formation schemes obtained were all 6.5 mm, and only one scheme had a rivet hardness of H4, the rest were H5. The SPR experiment is used to verify the current finite element simulation data can get the final research conclusion. The finite element simulation (FEM) would greatly reduce the test times of the SPR test, save the test consumables and save the test cost.

Bearing capacity and failure behavior of segments with a mid-span opening of a shield subway tunnel

This paper investigates the load-bearing properties and failure mechanisms of shield segments with a circular mid-span opening in shield subway tunnels. Two full-scale specimens with opening diameters of 100 and 200 mm were manufactured and tested, revealing that with an increasing opening diameter, the failure mode transferred from uniform tensile fracture of inner arc concrete to the peeling and crushing of the outer arc concrete. Moreover, the loading process can be divided into four stages, i.e. elastic, plastic expansion, failure, and ultimate stages, and each stage shares a critical load. Subsequently, numerical models were established using the elastoplastic damage constitutive of concrete, and its reliability is verified by the experimental results. Afterward, parametric analysis was performed considering the plain concrete loss and reinforced concrete loss. The analysis results show that the plain concrete loss significantly weakens the cracking load of the segment, while reinforced concrete loss has the greatest impact on the failure load. Finally, a comparative analysis is conducted between the bearing characteristics of the local failure segment, standard shield segment, and the segment joint. Overall, the research results can provide a theoretical basis for the field reinforcement and the safety assessment of local failed shield tunnels.

Five Machine Learning Models Predicting the Global Shear Capacity of Composite Cellular Beams with Hollow-Core Units

The global shear capacity of steel–concrete composite downstand cellular beams with precast hollow-core units is an important calculation as it affects the span-to-depth ratios and the amount of material used, hence affecting the embodied CO2 calculation when designers are producing floor grids. This paper presents a reliable tool that can be used by designers to alter and optimise grip options during the preliminary design stages, without the need to run onerous calculations. The global shear capacity prediction formula is developed using five machine learning models. First, a finite element model database is developed. The influence of the opening diameter, web opening spacing, tee-section height, concrete topping thickness, interaction degree, and the number of shear studs above the web opening are investigated. Reliability analysis is conducted to assess the design method and propose new partial safety factors. The Catboost regressor algorithm presented better accuracy compared to the other algorithms. An equation to predict the shear capacity of composite cellular beams with hollow-core units is proposed using gene expression programming. In general, the partial safety factor for resistance, according to the reliability analysis, varied between 1.25 and 1.26.

Comparing the morphology of optic nerve head and lamina cribrosa in full-term and preterm school-aged children.

To evaluate the morphology of lamina cribrosa (LC) in preterm school-aged children. A study of 120 eyes from 120 patients, including 42 full-term children (control group), 41 preterm children without retinopathy of prematurity (ROP), 16 children with ROP treated with intravitreal bevacizumab (IVB), and 21 children with ROP treated with laser. Five parameters of LC were measured by optical coherence tomography, including Bruch's membrane opening (BMO) diameter, minimum rim width (MRW), LC depth, prelaminar tissue (PLT) thickness, and LC curvature index (LCCI). The PLT thickness increased with age in full-term and preterm children (β = 30.1, P = 0.003 and β = 19.6, P < 0.001, respectively). LC depth and LCCI showed no differences between full-term and preterm children. Worse refractive errors in preterm children were associated with greater MRW and PLT thickness (β = -17.1, P = 0.001 and β = -5.7, P = 0.03, respectively). However, this relationship was not found in full-term children. Laser-treated children had greater MRW, PLT, temporal peripapillary retinal nerve fibre layer, and foveal thickness than full-term or other preterm children (all P < 0.05). Prematurity and ROP treatment may have an impact on the structural development of the LC. Refractive status plays a vital role in the LC structure of preterm children. This highlights the refractive errors of preterm children at school age that merit greater attention.

Bruch's Membrane Opening Changes in Eyes With Myopic Macular Degeneration: AIER-SERI Adult High Myopia Study.

The purpose of this study was to assess the choroidal thickness and the Bruch's membrane opening size and their relationship to visual acuity in eyes with myopic macular degeneration (MMD). This was a population-based, cross-sectional study. Patients over the age of 30years with high myopia (spherical equivalent ≤-5 diopters [D]) were recruited. The eyes were grouped according to the International Meta-Analysis for Pathologic Myopia (META-PM) classification based on fundus photographs and diffuse atrophy was subdivided into peripapillary diffuse choroidal atrophy (PDCA) or macular diffuse choroidal atrophy (MDCA). Swept-source optical coherence tomography imaging was performed and then the subfoveal choroidal thickness (SFCT) and Bruch's membrane opening diameter (BMOD) were measured. Of the 470 study participants recruited, 373 patients (691 eyes), with a mean age of 42.8 ± 7.2years, were eligible for the study and included in the analysis. There was no significant difference in SFCT between MDCA and patchy atrophy (M3) groups (P = 1.000), and the BMOD enlarged significantly from no myopic macular lesions to M3 (the P values of multiple comparison tests were all <0.005). Simple linear regression analysis showed that BMOD correlated positively with age (P < 0.001) and axial length (P < 0.001). Multiple linear regression analysis showed that best corrected visual acuity (BCVA) was significantly correlated with age (P = 0.041), axial length (P = 0.001), and BMOD (P = 0.017), but not with SFCT (P = 0.231). The significant variation of BMOD among MMD groups and the correlation between BMOD and BCVA in MMD eyes suggest that BMOD may be an imaging biomarker for monitoring MMD.

RS-AAT for enhancing saturation and chloride resistance in unsaturated concrete: Experimental and numerical assessment

In this paper, the effect of RS-AAT (Reverse-seepage and Saturation based Active Anti-corrosion Technology) on chloride ion erosion and saturation of unsaturated concrete is studied. The design of partially opening of permeable pipes is proposed for partial purpose. The infiltration of chloride ions in cylindrical concrete by RS-AAT is experimentally and numerically analyzed. Based on the water vapor adsorption and adsorption isotherm test and chloride ion erosion test, a convection-diffusion model of chloride ions with varying saturation is established by using simultaneous V-G model and Richards' equation. It can be used for characterizing the effect of pore opening on saturation change and chloride ion erosion. The results show that the use of RS-AAT can accelerate the growth of concrete saturation in the alternating wet and dry zones, and keep the area in a saturated state, under the effect of reverse seepage and saturation, the durability of the structure is increased. Moreover, the opening size and spacing of the permeable pipe are especially investigated. The results recommend 8 mm opening diameter and 2 mm opening spacing, by which the opening spacing is reduced as much as possible, and the ability to resist chloride ion erosion for a long time can be improved s under the combined action of reverse seepage and saturation. The significance of these results is immense for the continued utilization of the novel anti-chloride attack technology in engineering applications.

Burrow Morphological Characteristics of Soldier Crab (Dotilla myctiroides) on the Libong Island, Koh Libong Subdistrict, Kantang District, Trang Province, Thailand

Dotilla myctiroides, the soldier crab, digs burrows in sand flats and extracts nutrients from sediment. The present study investigated the burrow morphology of this soldier crab, at Laem Juhoi Beach, Libong Island, Koh Libong Subdistrict, Kantang District, Trang Province, Thailand. Randomly selected burrows were examined by injecting molten paraffin into them. The crab found inside a burrow was collected and measured for its carapace length. The shapes of the complete burrow casts were identified, and various morphological characteristics of the burrow casts were recorded. A total of 84 burrows were identified, all of them were the I-shaped or single-tube burrows. The burrows were categorized into two groups based on the burrow opening diameter: the &lt;12 mm group and the ≥12 mm group. The burrow opening diameter ranged from 7.50 to 20.10 mm while the end diameter at the burrow bottom ranged from 8.40 to 21.00 mm, and the total length of the burrows ranged from 27 to 206 mm. The carapace length showed a significant correlation (p&lt;0.05) with the burrow opening diameter in both groups. Additionally, the burrow opening with a diameter &lt;12 mm group had significantly greater hole distances than the burrow opening with a diameter ≥12 mm group (p&lt;0.05). The observed variations in hole distances suggest potential differences in ecological and behavioral factors that influence the burrow morphology of D. myctiroides in distinct size categories.

Performance improvement of a Stirling-type two-stage pulse tube cooler by using stepped displacer plus bypasses phase shifter

Stirling-type pulse tube cooler (SPTC) is the most prospective thermoacoustic refrigerator due to its long lifetime, high reliability and low vibration, and the phase shifter significantly affects the energy conversion efficiency of SPTC. A novel phase shifter of the stepped displacer plus bypasses (SD-B) is proposed in this paper. Thermoacoustic impedance characteristics of the stepped displacer (SD) and the stepped displacer plus bypasses (SD-B) are analyzed. Based on a two-stage SPTC, the effect of additional combined DC flows in the system is first investigated. Results indicate that the cooling capacity could be improved through introducing additional DC flows in the positive direction from the hot end of regenerator to pulse tube. While for SD, negative DC flows are induced due to the clearance seal gaps between the displacer piston and cylinder shell. Thus, SD-B is explored to improve energy conversion efficiency through naturally introducing DC flows by bypasses. The influence of the opening diameter of two bypasses is investigated, and comparisons between the SD and SD-B are performed. Results indicate that with SD-B, the cooling capacity at 20 K achieves a maximum of 2.04 W with a relative Carnot efficiency of 13.0 %, 56.9 % higher than that of SD.

Burrow Opening Measurements of Intertidal Macroinvertebrates from Optical Drone Images

Intertidal macroinvertebrates, such as crabs and mud shrimps, are invertebrates inhabiting the intertidal zone that are sufficiently large to be identified with the naked eye. Most intertidal macroinvertebrates typically construct burrows of various shapes in sediment to protect themselves from environmental extremes, with surface openings that reflect features of their species and body size. Especially circular burrow openings correlate with an organism’s body size; thus, measuring these openings can provide estimates of the organism’s size, weight, growth rate, and biomass. Traditional studies of these organisms have relied on field surveys, which are constrained by time, cost, and logistical limitations. This study introduces an innovative method for measuring the burrow opening diameters of intertidal macroinvertebrates using high-resolution optical images from a portable drone system. By leveraging the reflectance disparity between the sediment and burrow openings, this method facilitates the extraction and sizing of burrow openings. Our methodology was applied to three crab species known for their circular burrow opening: the red-clawed fiddler, the milky fiddler, and the ghost crab. Validation was confirmed through field data from the Mageumri and Sinduri tidal flats, South Korea. The method achieved a correlation coefficient (R2) of 0.94 and a root mean squared error (RMSE) of 1.68 mm across a diameter range of 6.21–33.59 mm. These findings suggest the potential of drone remote sensing systems as a non-invasive and efficacious approach for quantifying burrow sizes over extensive intertidal areas, thereby facilitating more accurate biomass estimations and surmounting the limitations of conventional field surveys. Future research could extend this method to additional species and further refine its precision.

Thermal Stress Mechanism of Thermochemical Reactor of 5 kW Solar Simulator with Temperature Distribution as the Load Condition

In this paper, a solar thermochemical reactor is designed based on a 5 kW non-coaxial concentrating solar simulator, and a mathematical model is established for thermal calculations. The calculated temperature distribution is used as a load condition for thermal stress analyses. The model is used to study the influence of the solar simulator power, solar reactor inner wall material’s emissivity, working pressure, gas inlet velocity, and thermocouple opening diameter on the thermal stress of the solar reactor. The results show that thermal stress increases with the increase in solar simulator power and the emissivity of the inner wall material in the solar reactor. The inlet velocity and working pressure have little effect on the thermal stress of the reactor and cannot prevent damage to the reactor. In the case of maintaining the diameter of the thermocouple at the front end of the reactor, increasing the diameter of the thermocouple inside the reactor leads to an increase in thermal stress around the reactor. Meanwhile, using a finer thermocouple can reduce the thermal stress inside the reactor and extend its service life, which will provide a foundation for designing practical industrial applications in the future.

Neovascularization by DPSC-ECs in a Tube Model for Pulp Regeneration Study

The process of neovascularization during cell-based pulp regeneration is difficult to study. Here we developed a tube model that simulates root canal space and allows direct visualization of the vascularization process in vitro. Endothelial-like cells (ECs) derived from guiding human dental pulp stem cells (DPSCs) into expressing endothelial cell markers CD144, vWF, VEGFR1, and VEGFR2 were used. Human microvascular endothelial cells (hMVECs) were used as a positive control. DPSC-ECs formed tubules on Matrigel similar to hMVECs. Cells were mixed in fibrinogen/thrombin or mouse blood and seeded into wells of 96-well plates or injected into a tapered plastic tube (14 mm in length and 1 or 2 mm diameter of the apex opening) with the larger end sealed with MTA to simulate root canal space. Cells/gels in wells or tubes were incubated for various times in vitro and observed under the microscope for morphological changes. Samples were then fixed and processed for histological analysis to determine vessel formation. Vessel-like networks were observed in culture from 1 to 3 d after cell seeding. Cells/gels in 96-well plates were maintained up to 25 d. Histologically, both hMVECs and DPSC-ECs in 96-well plates or tubes showed intracellular vacuole formation. Some cells showed merged large vacuoles indicating the lumenization. Tubular structures were also observed resembling blood vessels. Cells appeared healthy throughout the tube except some samples (1 mm apical diameter) in the coronal third. Histological analysis also showed pulp-like soft tissue throughout the tube samples with vascular-like structures. hMVECs formed larger vascular lumen size than DPSC-ECs while the latter tended to have more lumen and tubular structure counts. We conclude that DPSC-ECs can form vascular structures and sustained in the 3-dimensional fibrin gel system in vitro. The tube model appears to be a proper and simple system simulating the root canal space for vascular formation and pulp regeneration studies.

Reinforcement methods of an reinforced concrete beam with the circular opening in the plastic hinge region under cyclic loading

Transverse opening in the plastic hinge region of reinforced concrete (RC) beam is generally not recommended due to increased risk of shear failure rather than flexure or flexure-shear failure. However, in recent years, the actual pipeline configuration requirements have posed challenges in arranging such opening in the plastic hinge region of an RC beam member. To address this issue and propose design guidelines, this work examines the mechanical behavior of nine specimens subjected to cyclic loading. The test results are compared with the design methods suggested in other guidelines and research. Additionally, a set of design guidelines and novel reinforcement methods, utilizing Double-square hoop and U-shaped stirrups, are proposed and compared with traditional reinforcement methods for RC beams with circular openings. Three distinct regions for reinforcing beams with transverse circular openings are proposed based on their distance from the column support. In the first region, extending from three times the opening diameter to one beam depth (1H), the opening is reinforced with two inclined U-shaped stirrups on each side and double-square hoops on both faces. The second region (1H to 2H) utilizes one inclined U-shaped stirrup on each side, along with double-square hoops on both faces. Beyond twice the beam depth (2H) in the third region, the opening is reinforced solely with double-square hoops on both faces. The sets of design methods provide valuable insights for future design considerations.