Entry Angle Research Articles

A Methodological Approach to the Study of Retroreflective Pavements

Climate change, principally driven by human activities, has led to an increase in global temperature, which is predicted to continue rising in the coming years. This temperature increase is even more pronounced in urban areas due to the heat island effect. This phenomenon is highly influenced by the presence of paved streets made with bituminous mixtures, which are characterised by their high solar radiation absorption capacity. Bituminous mixtures retain and re-emit a large amount of heat that intensifies the urban heat island effect. The novelty of this work is to measure retroreflective properties of bituminous mixtures that present a highly textured surface. In this context, the aim of this study is to evaluate the retroreflectance of different bituminous mixtures for use as pavement surfaces, focusing on the influence of colour and different types of aggregates. For this, total and directional reflectance measurements were conducted to determine the retroreflectance of these mixtures, with the purpose of mitigating the heat island effect in urban environments without affecting users through reflected solar radiation. The results show the retroreflective capacity of the designed mixtures within the visible spectrum, especially those manufactured with light-coloured aggregates and synthetic binders pigmented with titanium dioxide. Thus, the retroreflectance of the lighter mixtures range from 37.9% at a 0° entrance angle to 68.9% at 60°, while the black mixtures exhibit values between 5.1% and 8.4%.

SURG-36. ACCURACY OF THE ROSA ONE BRAIN ROBOTIC PLATFORM FOR THE PLACEMENT OF NEUROBLATE AND VISUALASE LASER INTERSTITIAL THERMAL THERAPY PROBES

Abstract Laser interstitial thermal therapy (LITT) is a minimally invasive treatment option for patients with intracranial lesions. The success of LITT is dependent on accurate placement of the laser probe in target tissue. Placement can be facilitated by various stereotactic methods, including the Robotic Surgical Assistant (ROSA) ONE Brain robotic platform. The aim of this study is to examine the accuracy of stereotactic probe placement utilizing the ROSA robot. Primary outcomes were entry distance, target distance, and entry angle error. Accuracy differences between two major LITT platforms, the Neuroblate (Monteris Medical) and Visualase Systems, were compared. A prospective institutional database was used to identify all patients who underwent LITT for intracranial tumors utilizing the ROSA robot between 2013-2023. The sign test was used to compare error values to test their difference from a null value of 0. Spearman correlation was used to assess the relationship between angle of error and trajectory length. Kuskal-Wallis test was used to compare errors and trajectory length between the two companies. Of the 105 patients who underwent LITT during the study period, 337 probes were placed. For Visualase probes, median entry distance (1.1mm, IQR=0.4-2.0), target distance (1.6mm, IQR =0.9-2.4), and entry angle error (1.5°, IQR=0.9-2.5), were significantly different than zero (p=<.0001). For Neuroblate probes, median entry distance (1.5mm, IQR=1.0-2.1), target distance (1.8mm, IQR=1.1-2.4), and entry angle error (1.8°, IQR=1.1-2.5) were significantly different than zero (p=<.0001). When comparing laser systems, there was a significant difference in median entry distance error with Neuroblate having a higher error (1.5mm, IQR=1.0-2.1) than Visualase (1.1mm IQR=0.4-2.0, p=0.0041). Stereotactic placement of LITT probes utilizing the ROSA robotic system was not able to achieve perfect alignment with the planned trajectory. When comparing the systems, Visualase probes were placed more accurately at the entry point than Neuroblate probes.

Numerical Study of Air Cushion Effect in Notched Disk Water Entry Process Using Structured Arbitrary Lagrangian–Eulerian Method

This paper presents a novel numerical investigation into the air cushion effect and impact loads during the water entry of notched discs, utilizing the Structured Arbitrary Lagrangian–Eulerian (S-ALE) algorithm in LS-DYNA. Unlike prior studies that focused on smooth or unnotched geometries, the present study explores how varying notch parameters influence the fluid–solid coupling process during high-speed water entry. The reliability and accuracy of the computational method are validated through grid independence verification and comparisons with experimental data and empirical formulas. Systematic analysis of the effects of notch size, water entry velocity, and entry angle on the evolution of the free surface, impact loads, and structural responses uncovers several novel findings. Notably, increasing the notch diameter significantly enhances the formation and stability of the air cushion, leading to a considerable reduction in peak impact loads—a phenomenon not previously quantified. Additionally, higher water entry Froude numbers are shown to accelerate air cushion compression and formation, markedly affecting free surface morphology and force distribution. The results also reveal that varying the water entry angle alters the air cushion’s morphological characteristics, where larger angles induce a more pronounced but less stable air cushion, influencing the internal structural response differently across regions.

A microfluidic approach for controllable synthesis of TiO2 submicrospheres

TiO2 submicrospheres are used in dye-sensitized solar cells and Li-ion batteries to enhance energy conversion efficiency and volumetric performance. In this study, a microfluidic chip was designed for the realization of the continuous controllable synthesis of TiO2 submicrospheres. The chip utilizes two T-channels to discrete dispersed phases into droplets, and a Y-channel to fuse the two dispersed phase droplets. The droplets generation process, the influencing factors of droplet length and the fusion process of droplets were investigated. The effects of the flow rate ratio of titanium oxysulfate and ammonia solutions, microchannel geometrical profiles including the Y-channel entrance angle on the size of the synthesized TiO2 were studied. The length of the generated droplets was found to decrease with increasing continuous-phase flow rate, and increase with increasing dispersed-phase flow rate and microchannel cross-section area. When the flow rate ratio of titanium oxysulfate solution and ammonia solution was 1:1, the average diameter of TiO2 spheres synthesized was the smallest, around 300 nm. Increasing the microchannel cross-section and Y-channel entrance angle were beneficial in obtaining larger TiO2 submicrospheres. This proposed microfluidic strategy has the potential for applications required continuous synthesis of TiO2 submicrospheres with controllable sizes.

The Optimal Entry Point and Trajectory for Pedicle Screws to Avoid Superior Facet Joint Violation and Pedicle Penetration.

Background Accuracy is crucial in surgeries involving pedicle screws. This study aimed to determine the optimal screw entry points and trajectory angles for the pedicle screw technique used in the surgical treatment of lumbar instability. Methods To achieve this goal, a comparison was made between the screw entry points and trajectories determined using the commonly used intersection technique and those created in a three-dimensional (3D) simulation environment. Thirty-two cases of lumbar degenerative spondylolisthesis, selected from surgeries between 2018 and 2023, were included. Preoperative lumbar computed tomography (CT) images were converted into 3D models, and simulations for pedicle screw placement were conducted. Results Using the intersection technique, upper facet damage was noted in 31.3% of L1, 37.5% of L2, 6.3% of L3, and 31.3% of L5 segments. Adjustments to entry points and angles in the 3D environment were made to determine optimal trajectories. The revised screw angles showed statistically significant improvements at L1, L2, and L5 segments compared to the intersection technique. Conclusions The intersection technique does not appear safe in preserving the superior facet joint. A more lateral and caudal pedicle entry should be preferred in the upper segments, and at L5, a more lateral pedicle entry should be used. Consequently, the screw angles should be adjusted accordingly.

Constructing a model of the axis form in a S-shaped riser of a cultivator paw

When cultivating the soil, a force of resistance to the movement of cultivator paw acts on it. It has a variable value and causes a moment of force applied to the riser of the paw. Under the action of the moment, the elastic axis of the riser changes its shape. This affects the position of the paw in the soil. The form of an S-shaped riser whose elastic axis consists of two circle arcs has been considered in this study. During cultivator operation, one part of the riser bends, increasing the curvature of the elastic axis, and the other, on the contrary, unbends, that is, its curvature decreases. The modeling of the shape of the elastic axis of the paw riser is based on the theory of resistance of materials, according to which the curvature of the elastic axis of the cantilevered band is directly proportional to the applied moment and inversely proportional to its stiffness. If the shape of the cross-section of the riser along its entire length is unchanged and the properties of the metal are also the same, then the stiffness is constant. In the case of small deflections of the band, the linear theory of bending is used, but the deflections in the riser are significant, so the nonlinear theory has been used for this case. At the same time, it is taken into account that the elastic axis of the riser already has an initial curvature, the sign of which changes after passing through the point of connection of the component arcs. To model the shape of the elastic axis of the S-shaped paw riser, the deformation of the arcs of the circles that form this paw was calculated separately. Numerical integration methods were used to find the shape of the deformed elastic axes of both parts of the riser. They were connected into a whole and a deformed elastic axis of the S-shaped riser was obtained. Two variants of the riser with different lengths of their elastic axis, but the same height and the same angle of entry into the soil, were considered. The combination of the component arcs of the riser shows that, under the action of the same force, the deviation from the specified movement depth for one riser is 2 cm, and for the other – 4 cm.

Dynamic fluid-structure interaction between the projectile and the light-thin ice under the motion state in the polar environment

The interaction between projectiles and ice during water entry is crucial for advancing polar resource exploration and military operations in polar regions. This study introduces a fluid-structure interaction (FSI) model to simulate the dynamics between projectiles and light-thin ice under a motion state, validated through laboratory experiments. It examines the cavity evolution patterns during water entry and analyzes the motion states and dynamic characteristics of both the projectile and the floating ice. The influence of the horizontal-to-vertical velocity ratio (u*) and the initial pitch angle (φ) on the water entry process and collision dynamics has also been considered. The results reveal that as the projectile approaches the floating ice, it generates a wave-making effect, impacting the formation of the water entry splash crown and the deflection motion of the ice. Additionally, the hydrodynamic force acting on the projectile increases by 40 % compared to free water entry conditions. After the collision between the projectile and the light-thin ice, the pinch-off characteristics of the water entry cavity alter. This collision influences the motion state and dynamic characteristics of the projectile, while the ice experiences both collision and hydrodynamic forces, leading to passive motion. With an increasing water entry velocity ratio, the light-thin ice forms an expanding cavity during passive water entry, affecting the cavity pinch-off of the projectile. When u* > 1, the projectile exhibits circuitous motion post-collision with the ice. Variations in water entry angles of the projectile alter the collision mode between the projectile and the ice, resulting in changes to their motion states and dynamic characteristics. A critical pitch angle exists during the cavity pinch-off process.

A Multivariate Approach to Quantifying Risk Factors Impacting Stereotactic Robotic-Guided Stereoelectroencephalography.

Stereoelectroencephalography (SEEG) is an important method for invasive monitoring to establish surgical candidacy in approximately half of refractory epilepsy patients. Identifying factors affecting lead placement can mitigate potential surgical risks. This study applies multivariate analyses to identify perioperative factors affecting stereotactic electrode placement. We collected registration and accuracy data for consecutive patients undergoing SEEG implantation between May 2022 and November 2023. Stereotactic robotic guidance, using intraoperative imaging and a novel frame-based fiducial, was used for planning and SEEG implantation. Entry-point (EE), target-point (TE), and angular errors were measured, and statistical univariate and multivariate linear regression analyses were performed. Twenty-seven refractory epilepsy patients (aged 15-57 years) undergoing SEEG were reviewed. Sixteen patients had unilateral implantation (10 left-sided, 6 right-sided); 11 patients underwent bilateral implantation. The mean number of electrodes per patient was 18 (SD = 3) with an average registration mean error of 0.768 mm (SD = 0.108). Overall, 486 electrodes were reviewed. Univariate analysis showed significant correlations of lead error with skull thickness (EE: P = .003; TE: P = .012); entry angle (EE: P < .001; TE: P < .001; angular error: P = .030); lead length (TE: P = .020); and order of electrode implantation (EE: P = .003; TE: P = .001). Three multiple linear regression models were used. All models featured predictors of implantation region (157 temporal, 241 frontal, 79 parietal, 9 occipital); skull thickness (mean = 5.80 mm, SD = 2.97 mm); order (range: 1-23); and entry angle in degrees (mean = 75.47, SD = 11.66). EE and TE error models additionally incorporated lead length (mean = 44.08 mm, SD = 13.90 mm) as a predictor. Implantation region and entry angle were significant predictors of error (P ≤ .05). Our study identified 2 primary predictors of SEEG lead error, region of implantation and entry angle, with nonsignificant contributions from lead length or order of electrode placement. Future considerations for SEEG may consider varying regional approaches and angles for more optimal accuracy in lead placement.

Influence of feed entrance angle on transverse tearing burr formation in the milling of superalloy honeycomb with ice filling constraint

In the end milling of superalloy honeycomb cores, the contact form between the cutting tool and honeycomb wall and the force state of the honeycomb wall are variable, there will be difficulties in chip removal. The irregular extension of transverse tearing burrs can deteriorate the machining quality of honeycomb core surfaces, thereby adversely affecting the assembly and service performance of sandwich structures. Based on kinematic analysis, modeling of the removal and deflection process of honeycomb walls was conducted. The feed entrance angle in the case of machining thin walls with high feed speeds was characterized, and the force state of the honeycomb wall and the degree of shear or compression it bears were analyzed. Analytical models of damage scale and single-tooth cutting state were established under different feed entrance angles. The impact of feed entrance angle on the minimum burr length and the minimum constraint failure width was analyzed. The milling experiments of GH4099 superalloy honeycomb wall with ice filling constraint were designed and conducted to clarify the influence of different feed entrance angles on cutting force and transverse tearing burr length. The morphology of burrs and the wear form of the cutting tool were analyzed, and the formation mechanism of transverse tearing burr on the honeycomb sidewalls was revealed. The research results indicate that the feed force Fx is 2.1 to 4.7 times greater than the main force Fy or the back force Fz. When the feed entrance angle is <90°, transverse tearing burrs either do not occur, or occur crimped burrs that are gradually removed. Particularly within the range of 0° to 30°, the machining quality is better. The cutting force has a significant shearing effect on the honeycomb wall, making it susceptible to plastic deformation and reaching the fracture strain. The cutting edge can effectively remove material from the honeycomb wall, resulting in normal wear on the minor flank face and tip of the cutting tool. When the feed entrance angle is greater than 90°, it is easy to form large banded burrs, and the burr length is relatively similar to about 1500 μm. The cutting force has a significant extrusion effect on the honeycomb wall, resulting in minimal deflection deformation of the honeycomb wall, and making it difficult to fracture. The cutting tool fails to perform effective cutting, leading to increased friction between the cutting tool and honeycomb wall, which continuously induces irregular extension of the burrs. The research findings are of great significance for achieving damage control in metal honeycomb core machining and guiding process and clamping optimization.

Super-Microsurgery for Vessels with Diameters Smaller Than 0.5 mm.

Introduction: Among super-microsurgical techniques, the anastomosis of vessels smaller than 0.5 mm is very difficult to perform due to the small diameter and thinness of the blood and lymphatic vessel walls. In this article, we report on the main points of super microsurgery, particularly on the anastomosis of veins and lymphatic vessels with diameters smaller than 0.5 mm. Methods and Results: Details of anastomosis of vessels smaller than 0.5 mm. (1) The outer wall of the first blood vessel near the abrupt end hook with the tip of the needle in the needle holder. The entire abrupt end of the first blood vessel was supported by forceps in the surgeon's left-hand. (2) The surgeon decided the entry point and angle of the needle while moving the tip. After the needle was fixed, a force was applied so that the needle could pass through to the vascular wall. (3) After the needle passed through, the tip was confirmed to be located in the lumen of the first blood vessel. (4) The tip of the needle was inserted into the lumen of the second blood vessel, and the bite was adjusted while touching the second blood vessel through the endometrium. (5) Once the tip was properly positioned, counter-traction was applied by holding the entire outer wall with a left-hand forceps. (6) The needle was held near the tip and pulled out along its curvature. The anastomosis time was 11.35 minutes on average (9 to 14 minutes). The patency rate for all 20 anastomosis procedures was also 100%. Conclusion: The important points of LVA for lymphatic vessels and veins smaller than 0.5 mm were reported. Once the surgeons are familiarized with this anastomosis procedure, they can typically perform one anastomosis in about 10 minutes.

Cosmogenic radionuclides in meteorites from the Otway Massif blue ice area, Antarctica: An unusual, well‐preserved H5 chondrite strewn field

AbstractThe US Antarctic Search for Meteorites (ANSMET) discovered a dense cluster of 88 ordinary chondrites with a total mass of more than 100 kg on a blue ice area (BIA) of 1.6 × 0.3 km2 near the Otway Massif, Grosvenor Mountains, Antarctica. The larger masses (weighing up to 29 kg) were found at one end of an oval‐shaped pattern and the smaller masses (50–200 g) at the other end. We measured concentrations of the cosmogenic radionuclides 10Be (half‐life—1.36 × 106 year) and 36Cl (3.01 × 105 year) in the metal fraction of 17 H chondrites, including 14 fragments of this cluster, to verify the hypothesis that this meteorite cluster on the Otway Massif BIA represents a meteorite strewn field produced by the atmospheric breakup of a single meteoroid. The 10Be and 36Cl concentrations confirm that 10 out of 14 H chondrites from different locations within this small area are paired fragments of the same meteorite fall, while the four other H chondrites represent two additional—smaller—falls. The radionuclides suggest a pre‐atmospheric mass of 200–400 kg for the large pairing group, suggesting that 25%–50% of the meteoroid survived atmospheric entry. Based on the distribution of the paired H chondrites and evidence of their common cosmic‐ray exposure history in space, we conclude that most of the 88 meteorites within this small area represent a meteorite strewn field. The small size of the strewn field suggests that the meteoroid entered at a steep angle (&gt;60°), while the low amount of fusion crust on most meteorite surfaces most likely indicates atmospheric break up at low altitude, while additional fragmentation of a large surviving fragment may have occurred during impact on the ice. This well‐documented strewn field provides a good opportunity to apply model simulations of the atmospheric fragmentation of this object as a function of entry angle, velocity, and meteoroid strength. Cosmogenic 14C analyses in two members of the Otway Massif pairing group yield a terrestrial age of 15.5 ± 1.5 kyr, which represents the time elapsed since this meteorite fell on Earth. The excellent preservation of an Antarctic meteorite strewn field suggests that the Otway Massif BIA represents a relatively stagnant blue ice field.

Biomechanical model of minimally invasive hallux valgus surgery

Hallux valgus is a common foot deformity characterized by outward tilting and twisting of the big toe, often accompanied by a medial prominence at the base. Minimally invasive surgical techniques are widely utilized for treating metatarsus adductus due to their advantages of smaller incisions, faster recovery, and early weight-bearing. However, due to individual variations and limited sample size, the biomechanical effects of different Kirschner wire fixation methods and the underlying mechanisms of postoperative metatarsalgia remain unclear. In this study, a finite element method was employed to develop a biomechanical model of metatarsus adductus. The influence of various Kirschner wire entry points and angles on foot loading characteristics was investigated. Six different Kirschner wire fixation models, including two entry methods (along the adjacent fracture line and proximal-biased entry at the midshaft of the metatarsal) with different entry angles, were analyzed. Mechanical parameters such as metatarsal stress distribution, plantar pressure distribution, and displacement of the first metatarsal osteotomy plane were assessed. This research aims to enhance understanding of minimally invasive surgery and its fixation methods for metatarsus adductus. By providing scientific support and reliable evidence, it seeks to contribute to the development of minimally invasive surgical techniques and the improvement of clinical practice in metatarsus adductus surgery. Ultimately, the goal is to reduce complications, increase surgical success rates, and enhance patient satisfaction.

Numerical study on the motion characteristics of free fall lifeboats entering calm water and rough sea

As ocean engineering operations extend into deeper seas, the working environment becomes increasingly complex, making free fall lifeboats (FFLBs) more vital for maritime disaster rescues. Unlike traditional davit-launched lifeboats, FFLBs are propelled into the water at a specific velocity and angle, engaging in a complex motion process of launch, impact, submersion, and resurfacing. Therefore, to assess the safety of FFLBs, this paper regarding the lifeboat as a rigid body aims to investigate the six-degree-of-freedom motion characteristics of lifeboat entering the water with different entry angles θ and wave environment, with a specific focus on analyzing the primary causes of capsizing. The numerical simulations of water entry with various θ, wave heights H, and relative entry positions are carried out by combining large eddy simulation and overset mesh technology. The free surface is captured by the volume of fluid method, and the attitude change, acceleration change, motion trajectory, and free surface evolution law of lifeboats are analyzed. The findings suggest that lifeboats can enter calm water safely at θ of 20°–50° and maintain a stable posture. Moreover, in extreme conditions where θ is either 0° or 90°, there is a high risk of entry failure due to excessive vertical acceleration and poor motion attitude, respectively. Furthermore, when facing waves, lifeboats experience reduced horizontal displacement when entering at peak and downward zero point compared to calm water conditions, which poses challenges for avoiding potential dangers.

Parametric Analysis and Numerical Optimization of Root-Cutting Shovel of Cotton Stalk Harvester Using Discrete Element Method

Aiming at solving the problems of the high cost of manual pulling, the low reliability of existing pulling devices, and the high breaking rates and high leakage rates in the process of cotton stalk reuse after removal from the field in the Xinjiang cotton area, a soil-loosening and root-cutting cotton stalk pulling and gathering machine was researched and designed; a root-cutting force model was established; the key parameters of the V-shaped root-cutting knife were calculated and optimized; and the ranges of the slide cutting angle, the cutting-edge angle, and the soil entry angle were determined. A shoveling process simulation of the V-shaped root-cutting knife and the root–soil complex was constructed, and the working mechanism of the V-shaped root-cutting knife was clarified. In order to verify the reliability and operation performance of the V-shaped root-cutting knife, the slide cutting angle, the cutting-edge angle, and the soil entry angle were used as the test factors, and a response surface test with three factors and three levels was carried out with the root-breaking force and the mean value of the cutting resistance as the test indices. The test results were analyzed by variance analysis, and the significant factors influencing the root-breaking force in descending order were the slide cutting angle, cutting-edge angle, and soil entry angle. The degrees of influence on the mean value of the cutting resistance were ordered as follows: slide cutting angle, soil entry angle, and cutting-edge angle. In order to make the V-shaped root-cutting knife achieve the optimal working state, the parameters of the test indices were optimized, and the optimal design parameters of the V-shaped root-cutting knife were set as follows: the slide cutting angle was 48.3°, the cutting-edge angle was 43.4°, and the soil entry angle was 26.2°. The field uprooting test showed that the average pass rate of root breakage was 94.8% and the average pull-out rate of cotton stalks was 93.2%. This study provides theoretical guidance for the development of a root-breaking mechanism for cotton straw harvesters.

Robotic MR-guided high dose rate brachytherapy needle implantation in the prostate (ROBiNSon)—a proof-of-concept study

Objective. A robotic needle implant device for MR-guided high-dose-rate (HDR) prostate brachytherapy was developed. This study aimed to assess the feasibility and spatial accuracy of HDR brachytherapy using the robotic device, for a single intraprostatic target point. Approach. Five patients were treated from November 2019–June 2022 with the robot. The robot fits a 1.5 T MR scanner and the needle can be shifted and angulated. An intraprocedural MR scan was fused with the diagnostic MR and one preplanned needle position was selected for robotic insertion. The needle entry point and angles were set for a needle tip target point within the intraprostatic target volume. The needle was tapped stepwise towards the target point pneumatically. Final needle position was verified with MR, followed by plan optimization and dose delivery. Any remaining planned needles were inserted manually. Needle tip to geometrical target error (NTG-error) was defined as the deviation of the actual tip position relative to the predefined geometric target point, using MR-coordinates. Needle tip to treatment target error (NTT-error) was defined as the deviation of the actual tip position relative to the treatment target point, using fused MR-images pre- and post-needle implantation taking into account prostate deformation. Difference between NTT-error and NTG-error and fiducial marker shifts indicated prostate movement. For determining prostate deformation, the Jaccard index and prostate volumes were assessed. Main results. The robotic device was able to tap the needle to the planned depth for all patients. Mean robotic procedure duration was 142 min. NTG-error was 3.2 (range 1.1–6.7) mm and NTT-error 4.5 (range 2.6–9.6) mm. Marker displacements were smaller than 3 mm. No treatment-related acute toxicity was reported. Feasibility of needle placement within the prostate was considered adequate. Significance. MR-guided robotic needle insertion is feasible with a mean geometric accuracy of 3.2 mm and <3 mm prostate movement.

Effects of entry angle on the water-entry cavity and motion hydrodynamics of a hollow cylinder

Effects of entry angle on the water-entry cavity and motion hydrodynamics of a hollow cylinder

Ctenopharyngodon idella’s Movement Behavior in Response to Hydraulics at Fishway Entrance with Different Entrance Angles

The hydrodynamics at the fishway entrance play an important role in attracting fish into a fishway. Adjusting the entrance angle of the fishway to allow suitable water flow patterns at the entrance is an effective measure that can be used to improve the attraction efficiency. In this study, we analyzed the movement behavior of grass carp (Ctenopharyngodon idella) in a river channel at a fishway entrance with different fishway entrance angles (30°, 45°, and 60°) and different replenishment velocities (0.1 m/s, 0.2 m/s, and 0.3 m/s). The flow velocity was 0.32–0.50 m/s when the fish head deflected into the entrance under different entrance angles for grass carp. As the entrance angle of the fishway increased, the fish energy consumption increased. The range of energy consumption for grass carp increased from 1.26–3.59 × 10−3 J to 3.32–7.33 × 10−3 J when the entrance angle was increased from 30° to 60°. There was a negative correlation between the entrance angle of the fishway and the deflection angle of the tested fish’s head. This research presents a reference that combines fish swimming behavior and hydraulics to optimize the design of fishway entrances.

Insights into water-lubricated transport of heavy and extra-heavy oils: Application of CFD, RSM, and metaheuristic optimized machine learning models

With diminishing light crude oil reserves, the focus shifts to heavy and extra-heavy crude oil, posing challenges with high viscosity impeding flow. Water-lubricated technology addresses this issue in oil transmission lines. This study introduces a novel method integrating response surface methodology (RSM), computational fluid dynamics (CFD), and optimized machine learning (ML) models to analyze pipeline pressure gradients (PG) in oil–water two-phase flows downstream of T-junctions. The present study uses the D-optimal technique for simulation design to optimize CFD computational demands efficiently. This study breaks new ground by proposing a framework that leverages support vector machines (SVMs). The proposed framework incorporates metaheuristic optimization algorithms (genetic algorithm (GA) and particle swarm optimization (PSO)) to achieve superior PG prediction accuracy. The optimized ML models outperformed RSM models for predicting PG. Results indicated that oil-to-water viscosity ratio and oil inlet velocity significantly affect PG, followed by water inlet velocity and surface tension between phases. In contrast, the oil-to-water density ratio, oil entry angle at the T-junction, and wall contact angle have minimal impact. Furthermore, statistical metrics and visual comparison tools identified the PSO-optimized SVM model based on linear kernel function as the most effective (MAPE = 13.2 % and R = 0.9949). The hybrid methodology presented in this research holds significant promise for optimizing heavy oil transfer efficiency in applications involving water-lubricated technologies.

Comparison of the Accuracy and Efficiency of Two Dynamic Navigation System Workflow for Fiber-post Removal: Small versus Large Field-of-view Registration Workflows

IntroductionThis study investigates the feasibility of a dynamic navigation system (DNS) small field of view workflow (DNS-SFOVw) for fiber-post removal and compares its accuracy and efficiency to the conventional large field of view workflow (DNS-LFOVw). MethodsFifty-six extracted human maxillary molars were divided into DNS-SFOVw (n = 28) and DNS-LFOVw (n = 28). The palatal canal was restored with an intraradicular RelyX fiber post and luted with RelyX Unicem; a core buildup was used. Teeth were mounted in a 3D-printed surgical jaw. A preoperative cone-beam computed tomography (CBCT) scan was taken with a 40 × 40 mm FOV for the DNS-SFOVw and a single arch CBCT scan for the DNS-LFOVw. The drilling entry point, trajectory, angle, and depth were planned in the X-guide software. The DNS registration method for the DNS-SFOVw was virtual-based registration on teeth, and the marker point-based method was used for the DNS-LFOVw. The fiber posts were drilled out under DNS guidance. A postoperative CBCT scan was taken. Three-dimensional deviations, angular deflection, number of mishaps, registration, and total operation time were calculated. ResultsThe DNS-SFOVw was as accurate as DNS-LFOVw (P > .05). The DNS-LFOVw registration time was less than DNS-SFOVw (P < .05). There was no difference in the number of mishaps (P > .05). Both DNS-SFOVw and DNS-LFOVw were time-efficient, with DNS-LFOVw taking less total operational time (P < .05). ConclusionWithin the limitations of this in-vitro study, the DNS-SFOVw was as accurate as the DNS-LFOVw for fiberpost removal. Both DNS-LFOVw and DNS-SFOVw were time-efficient in removing fiber-posts.

Evaluation and Spatial Correlation of Agricultural Green Investment Efficiency in China

Green agriculture is one of the development directions of modern agriculture, and now the development of green agriculture needs the support of capital and technology. Under the background that China attaches great importance to the development of green agriculture, the government has introduced a series of relevant policies. Therefore, by exploring the problem of investment efficiency in the development of green agriculture in our country, optimizing the investment direction, and constantly promoting the development of green agriculture, there is no doubt that it has important practical significance. Through normative analysis and empirical analysis methods, this paper conducted in-depth research on the efficiency of green investment in agricultural science and technology, the development prospect of agricultural green industrial structure, and the impact of green agricultural economy on green investment, analyzed several key impacts of improving the efficiency of agricultural green investment on the development of agricultural industry, and then elaborated the reaction of agricultural green investment on the entire economic development. This paper also innovatively explores from the Angle of entry and analysis methods, and continuously analyzes the investment effect of "high investment efficiency, low investment level and high overall income growth" formed by the gradual improvement of green technology investment efficiency, the continuous decline of green investment level and the continuous reduction of green investment cost.