Tip Angle Research Articles

Simulation design and experimental study of beveled angle narrow-slit needleless electrospinning spinneret

Needleless electrospinning technology is considered an effective way to produce nanofibrous materials on a large scale. The electric field strength and its distribution during the electrospinning process play an essential role in controlling the diameter and quality of the nanofibrous membrane. To achieve the mass production of nanofibers, this study proposed the design concept of a new type of needleless electrospinning spinneret with a beveled tip and narrow slit shape. The finite element analysis software of Comsol Multiphysics 6.0 was used to simulate the electric field contour of the new type of needleless electrospinning spinneret with a beveled tip and narrow slit shape. In performing the simulation of electrospinning with this spinneret, the values of the electric field strength on the surface of the spinneret and the variation of its electric field strength distribution curve were obtained. The optimal beveled narrow-slit spinneret structure was determined by varying the beveled tip angle, inner ring material, applied voltage, and receiving distance. The results showed that the highest value of electric field strength at the tip of the spinneret could be obtained when the inner ring was made of PTFE and the beveled narrow-slit spinneret was at 120°. Finally, the polyurethane nanofiber membrane was successfully fabricated using this new type of electrospinning spinneret. The nanofiber membrane with a mass fraction of 17% had a good micro-morphology. The diameter distribution was very uniform, and the average diameter was 624 nm. The production was up to 9.6 g/h, which was 96 times higher than that of single-needle electrostatic spinning. The feasibility of mass production of nanofiber membranes using this novel spinneret was verified.

Effects of swirl on nonreacting and reacting flows in a single-element lean direct injection combustors

PurposeThe swirl intensity imposed on the flow plays a vital role in aerodynamics, flame shape, flame stabilization and combustion intensity. In lean direct injection (LDI), the air and fuel are fed through separate channels, and the swirling air flows have a strong impact on fuel-air mixing and heat release. The literature indicates that the effects of swirling on helical axial LDI systems are limited to nonreacting flows studied through experimental methods, but not many studies have been reported on the reacting flows of a single swirler. The objectives of the paper are divided into two parts. The first part presents the role of swirl in nonreacting LDI systems and the second part describes spray combustion in LDI systems for low (swirl < 0.5) to high (swirl > 0.5) swirl numbers.Design/methodology/approachThe numerical model incorporates all the necessary features of the single helical axial swirler, starting from the hollow circular section to the outlet of a long mixing chamber. The commercial solver FLUENT is used to predict the flow field around the axial swirler. The first step is to establish a numerical procedure (based on computational fluid dynamics [CFD]) to predict the nonreacting flow behavior for different swirlers and the CFD results are validated against literature data. The spray atomization, droplet evaporation and the effects of interaction between the two phases are modeled by implementing various spray submodels in FLUENT. The large Eddy simulation (LES) reacting flow results for a vane tip angle of 60° are compared with test data and presented at multiple cross planes.FindingsThe numerical simulations were carried out on a nonreacting single helical axial swirler for various vane tip angles, such as 40°, 50°, 55, and 60°, and the results were validated against test data. The centerline mean axial velocity and radial velocity profiles at several axial locations are in good agreement with the literature data. For reacting swirling flows, the experimental data is available only for a 60° vane tip angle. The S60 reacting flow LES mean predictions are compared at different cross planes. The axial momentum increases due to the liquid spray combustion in the gas phase and the reacting flow central recirculation zone is substantially shorter than the nonreacting flow. The impact of spray atomization due to interaction with the gas phase is verified, and the droplet mean diameter trends are consistent across different cross planes. The LES predictions of reacting flows for low to high swirls are investigated, and the effects on combustion performance are summarized.Originality/valueThe novelty of the paper is highlighted in two key conclusions. First, the paper presents numerical methods for studying the role of swirl in a nonreacting LDI system and validates the results against experimental data. Second, the effects of combustion on the gas phase, spray combustion modeling and droplet atomization are numerically established and compared with literature data for a 60° vane tip angle. In addition, the role of swirl in the reacting flow field for vane tip angles of 40°, 50° and 60° is numerically investigated, and its effect on flame stability, pressure drop and NOx emissions is presented. The paper describes LES grid guidelines for the LDI swirler and presents a numerical modeling approach that helps to develop a robust swirler design through a parametric investigation of swirler geometry. The methodology can be extended to study multi-element swirler configurations, to understand the effect of swirl on droplet breakup, momentum exchange with adjacent swirlers, flame propagationand emissions.

Numerical Study of Tungsten Cathode Characteristics During TIG Welding

Tungsten Inert Gas (TIG) is widely utilized across various industries. The understanding of tungsten electrode behavior, key component in this process, is vital for optimizing processes and enhancing weld quality. The shape of the electrode tip, influenced by its operational characteristics, significantly impacts the behavior of the electric arc and, consequently, the quality of the welded assembly. This study aims to analyze the influence of current intensity on the thermal and electrical characteristics of the cathode tip during TIG welding, using numerical simulations conducted with Comsol software. The analyses are carried out by applying Direct Current (DC) welding on an aluminum alloy sheet. The results show a similar evolution in the operational characteristics of the electrode as its tip angle varies. In contrast, the current intensity affects only the temperature, which increases with a higher tip angle, while the current density depends solely on the geometry of the electrode tip. The appropriate selection of welding parameters is imperative to preserve the electrode shape and ensure an efficient welding process.

Comparison of wear on the surfaces of denture base resins based on the type and application angle of ultrasonic scaler tips

Comparison of wear on the surfaces of denture base resins based on the type and application angle of ultrasonic scaler tips

Effect of Autogenous Auricular Cartilage Composite Skin Graft for Bilateral Cleft Lip Nose Deformity Repair.

Bilateral cleft lip nose deformity often involves nasal alar retraction. The use of autogenous auricular cartilage for correction further aggravated nasal alar retraction caused by nasal lining defects after the operation. A novel graft was developed to address bilateral cleft lip nose deformity. This graft effectively addresses the lining defect and avoids nasal alar retraction following surgical intervention. Seventeen patients (7 males and 10 females) with bilateral cleft lip nose deformity were treated at the authors' institution. All patients underwent repair with an auricular cartilage-composite skin graft. The surgical effect was evaluated from 4 aspects: nasal flange position, postoperative appearance satisfaction, nasal aesthetic subunit index, and three-dimensional difference. Postoperatively, 17 patients with bilateral cleft lip nose deformity were followed up from 3 months to 1 year, none of them had any obvious inward collapse or recession of the nasal margin (P > 0.05), and all of them showed satisfactory results. The satisfaction rate was above 90% (P < 0.01). The nasal tip angle and nasolabial angle were significantly smaller postoperatively than those preoperatively (P < 0.01). The nostril height and nasal columellar height were greater postoperatively than those preoperatively (P < 0.01). A comparison of the three-dimensional spatial differences revealed that the appearance of the nasal deformity was noticeably better after surgery (P < 0.01). Auricular cartilage-composite skin graft repair is highly effective for enhancing nasal support, correcting nasal tip shape, effectively resolving nasal flange recession, and preventing nasal flange retraction in the postoperative period. Level IV.

Development of Pyramidal Microwells for Enhanced Cell Spheroid Formation in a Cell-on-Chip Microfluidic System for Cardiac Differentiation of Mouse Embryonic Stem Cells.

Three-dimensional (3D) tissue culture models provide in vivo-like conditions for studying cell physiology. This study aimed to examine the efficiency of pyramidal microwell geometries in microfluidic devices on spheroid formation, cell growth, viability, and differentiation in mouse embryonic stem cells (mESCs). The static culture using the hanging drop (HD) method served as a control. The microfluidic chips were fabricated to have varying pyramidal tip angles, including 66°, 90°, and 106°. From flow simulations, when the tip angle increased, streamline distortion decreased, resulting in more uniform flow and a lower velocity gradient near the spheroids. These findings demonstrate the significant influence of microwell geometry on fluid dynamics. The 90° microwells provide optimal conditions, including uniform flow and reduced shear stress, while maintaining the ability for waste removal, resulting in superior spheroid growth compared to the HD method and other microwell designs. From the experiments, by Day 3, spheroids in the 90° microwells reached approximately 400 µm in diameter which was significantly larger than those in the 66° microwells, 106° microwells, and HD cultures. Brachyury gene expression in the 90° microwells was four times higher than the HD method, indicating enhanced mesodermal differentiation essential for cardiac differentiation. Immunofluorescence staining confirmed cardiomyocyte differentiation. In conclusion, microwell geometry significantly influences 3D cell culture outcomes. The pyramidal microwells with a 90° tip angle proved most effective in promoting spheroid growth and cardiac differentiation of mESC differentiation, providing insights for optimizing microfluidic systems in tissue engineering and regenerative medicine.

Electrochemical Behaviors of Ultramicro Triangular Pipettes.

Ultramicro pipettes with circular orifices have practically become common probes in exploring the microscopic world, yet the versatility of differently shaped pipettes is undermined in the pore family. Herein, ultramicro triangular pipettes with a pseudotriangular-shaped orifice were fabricated by laser-pulling triangular quartz capillaries and characterized by microscopic and electrochemical methods. Then, the differences in the electrochemical behaviors of triangular and circular pores were revealed through experiments and simulations. A liquid/liquid interface was supported first at a triangular pipette, and the facilitated potassium ion transfer reactions exhibited steady-state voltammetric responses. An empirical equation for triangular pores between the diffusion-limited current and the side length (a) of the orifice was evaluated, and the corresponding mass transfer coefficient of ion ingress was estimated as mTri = 8.05D/a. As for ion egress transfer, the tip angle and pore shape would affect the diffusion regime and the ion distribution, where the mass transfer would be enhanced at the corners of a triangular pipette with a large tip angle. Triangular submicropores and nanopores were employed to detect particle translocations at a high capture rate, though the events had broader distributions and lower charges than those of circular pores. These findings demonstrate the shape effect in triangular pores that promotes the mass transfer rate of interfacial ion transfer reactions and the capture rate of ionic blockades. The universal laser-pulling method could make ultramicro pores of arbitrary shapes accessible in fundamental studies and applicable as chemical sensors.

Radiation source detection for the accurate location of lymph node metastases using robotic forceps-type coincidence radiation detector.

We have developed a forceps-type coincidence radiation detector for supporting lymph node dissection in esophageal cancer treatment. For precise detecting, this study aims to measure the 2D point-spread function of the detector at three difference tip angles, to devise a method to determine the position of a point source using the 2D point-spread function. The 2D sensitivity distribution on the surface of the detector was investigated to assess sensitivity variation caused by differences in the relative positions of the detector and radiation source. Based on the results, we identified the peak sensitivity value and proposed a detection method using this value. We evaluated the effectiveness of the proposed method by detecting radiation source location using this simulated distribution. From the radiation sensitivity distribution measurements, we observed a gradual decrease in radiation detection sensitivity from the center toward the edges of the detector surface. Additionally, we verified that the peak sensitivity value was attainable. Through the basic verification of the detection method, we confirmed that the radiation source location could be detected within a maximum error of 1.4mm. We developed a peak value search method aimed at mitigating sensitivity variations by leveraging the sensitivity distribution across the detector surface. The proposed device is thought to be able to quantitatively evaluate the desired target assuming that the field of view could be limited to the area clamped by the detector. As a next research step, more precise search methods should be verified in an environment resembling the one of the target clinical uses.

Simulation analysis on ejector performance with inclusion of chevrons in primary nozzle

As an unconventional refrigeration system, the ejector refrigeration system (ERS) must achieve high performance. The performance of the ERS largely depends on the ejector’s entrainment ratio. In this numerical analysis, the effect of the inclusion of chevrons in the primary nozzle of the ejector has been studied. The three-dimensional, steady-state analysis has been carried out by solving turbulence and compressible equations, using periodic boundary conditions to study the mixing of the primary and secondary fluids. In this work, the chevrons have been incorporated in the primary nozzle to enhance the ejector’s entrainment ratio (ω) by improving the mixing of fluids. The reduction in the slip line between the two fluids has been found to be better in the chevron-incorporated nozzle than in the conical and bell-shaped nozzles. The number of chevrons (N) has been varied with a fixed tip angle (β=60∘). Analyzing 2, 4, 6 and 8 chevrons showed that the entrainment ratio of four chevrons increased by 12.98% of the conical nozzle.

Changes in Properties of Superalloy Powder According to Changes in Gas Spray Process Parameters

In this study, we investigated the production of Ni-based superalloy powder to repair turbine blades in gas turbines by 3D printing. The alloy powder was produced using gas atomization, and we investigated changes in the properties of the powder by varying the molten metal flow rate, orifice design, and gas injection nozzle to control the yield, particle size, and shape. The particle size and shape of the produced alloy powder were analyzed using a Particle Size Analyzer (PSA) and Scanning Electron Microscope (SEM). Additionally, Inductively Coupled Plasma (ICP) and Oxygen-Nitrogen-Hydrogen (ONH) analyses were conducted to verify the powder's composition and the levels of oxygen and nitrogen. The study found that using an orifice with an inner diameter of ∅6 mm and a tip angle of 32° at an injection pressure of 45 bar improved the yield of powder manufacturing. Furthermore, replacing a nozzle from 2 holes to 4 holes led to higher and more uniform production of alloy powder, enhancing the existing fuel and pressure system.

Optimizing CNC milling parameters for manufacturing of ultra-sharp tip microneedle with various tip angles.

Microneedle technology has emerged as an advanced method for transdermal drug delivery, which focuses on diverse fabrication techniques to develop microneedles with various models and geometries. This study explores the application of Computer Numerical Control (CNC) milling technology to create microneedle master molds with extremely sharp tips. We examined the effects of two key machining parameters, feed rate and ramp angle, on the tip sharpness of the microneedles. Our results showed that increasing both the feed rate and ramp angle could significantly reduce machining time. However, a higher feed rate also led to larger tip diameters and notable tip defects. Conversely, changes in the ramp angle at a constant feed rate had minimal impact on tip size. We identified an optimal condition balancing cutting time and tip sharpness at a feed rate of 100mm/min and a ramp angle of 1.5°. Additionally, we assessed the CNC's capability to produce needles with different tip angles. The findings confirm that needles with varying tip angles maintained tip diameters below 10μm, with needles having a 50° tip angle exhibiting the sharpest tips at approximately 3.3μm. Further compression, insertion and diffusion tests were conducted to evaluate the performance of needles with different geometries.

Cross‐Scale Process Intensification of Spindle CuO Supported Tungsten Single‐Atom Catalysts toward Enhanced Electrochemical Hydrogen Production

AbstractProcess intensification engineering of electrocatalysts is crucial to facilitate electrocatalytic reaction, while its cross‐scale modulation is of great challenge. Herein, the spindle CuO supported tungsten single‐atom catalysts (W SACs) with tunable mesoscale electric field and atomic‐scale coordination structure are reported toward enhanced electrochemical hydrogen evolution process. Finite element analysis indicates the mesoscale electric field can be enhanced by tailoring the tip angle of spindle configuration from 74° to 27°, enhancing hydrogen production rate by 5 times. Based on the density functional theory calculations, the configuration regulation also triggers the increase of coordination number of W–O, which increases charge transfer and downshifts d‐band center, stabilizing W sites and optimizing hydrogen desorption process. The optimized WSA/CuO‐27 exhibits much better hydrogen evolution activity (η100 = 94 mV) and stability (200 mA cm−2 for 120 h) than as‐prepared WSA/CuO‐56 and WSA/CuO‐74 analogues. Impressively, the anion exchange membrane electrolyzer fabricated with the WSA/CuO‐27 presents excellent activity comparable to that of commercial electrocatalysts, and also delivers an ultra‐low attenuation of 0.085 mA cm−2 h−1 at 300 mA cm−2 after continuous electrocatalysis for 120 h. This work inspires the design of high‐efficiency supported metal catalysts for electrochemical synthesis via the cross‐scale process intensification engineering.

Assessment of genetic diversity by phenological traits, field performance, and Start Codon Targeted (SCoT) polymorphism marker of seventeen soybean genotypes (Glycine max L.).

The Egyptian-farmed soybeans have a wide range of genetic diversity which is most important in plant improvement programs in order to develop new higher yielding soybean genotypes. The present study is designed to determine the genetic variability among seventeen genotypes of cultivated soybean (Glycine max L.) by examining the phenotypic level at the seedling stage, field performance over two years 2022/2023 and genetically using Start Codon Targeted (SCoT) markers. Results indicated that the SCoT markers, 100 seed weight, and tip angle (TA) traits were positively correlated with H2L12, DR 101, H15L5, and H117 genotypes. In addition, the number of branches per plant and plant height were associated with H113, H32, Crowford, H129, and D7512035. Furthermore, the length of the first internode (LFI), root width (RW), root length (RL), and shoot length (SL) were more associated with Giza 111, NC105, and Hutcheson. The hierarchical cluster analysis (HCA) and its associated heatmap explored the differences among the genotypes. It showed that all examined parameters were clustered into four distinct clusters. The obtained results showed that genotypes NC105, H30, D75_12035, and H2L12 have promising phenological and morphological traits besides tracking the inheritance of nearby genes surrounding the ATG translation start codon since they are in a monoclades. The obtained results will help the breeder plan appropriate selection strategies for improving seed yield in soybeans through hybridization from divergent clusters.

Three-dimensional analysis of presurgical nasoalveolar molding outcomes in patients with unilateral cleft lip and palate: A preliminary study using LED surface scanning technology

ObjectivesPresurgical infant orthopedic appliances, such as presurgical nasoalveolar molding (PNAM) devices, are used to attain optimal conditions for primary repair of the lip and nose (PRoLN) in patients with cleft lip. We aimed to analyze the three-dimensional (3D) outcomes of PNAM using an LED surface scanner. MethodsFifteen patients with unilateral cleft lip and palate (CLP) were included in this study and treated using a PNAM device. The patients’ faces were digitized pre- and post-PNAM using an Artec Space Spider scanner, and the scanned data were analyzed using 3D software (Geomagic Control X and ANSYS SpaceClaim). The columellar angle (CA), nostril curvature (NC) on the affected (NC_A) and unaffected (NC_U) sides, gap of cleft lip (GCL), alar width (AW), and nasal tip angle (NTA) were measured. ResultsCA increased significantly by 10.00° and NC_A by 0.030 mm-1 (p < 0.001). GCL decreased by 4.98 mm2 on average and NC_U by 0.015 mm-1 (p = 0.029 and 0.046, respectively). AW also decreased by approximately 1.22 mm pre- and post-treatment (p = 0.002), and NTA, which shows a lateral profile, decreased by approximately 3.32° (p = 0.002). ConclusionsThis study confirmed the orthopedic benefits of PNAMd treatment through 3D analysis using an LED surface scanner. Further studies involving a larger number of participants are warranted to study the effects of PNAM and analyze longitudinal changes in patients with CLP. Clinical SignificanceThis study shows that PNAM effectively corrects columellar deviation and nostril shape in patients with unilateral cleft lip, with 3D scanners enhancing primary lip and nose repair outcomes.

What Did the Ideal Beauty of the 15th Century Look Like? An Anthropometric Analysis of Botticelli Portraits.

The aim of this study was to conduct an anthropometric analysis of the 5 portraits painted by Botticelli that depict Simonetta Vespucci. Five images in the Simonetta series by Botticelli workshop were measured. The anthropometric measurements of the face included 22 parameters on the lateral view (in 4 portraits; 18 distances and 4 angles) and 17 distances on the frontal view (in one portrait), which were measured using Adobe Photoshop. The absolute distances were calculated relative to the vertical corneal diameter (10.6mm), which was calculated by multiplying the distance from the pupil's center to the lower margin of the iris. In the lateral faces, the nasofrontal angle (g-n-prn) was 157.6±2.4 degrees, and the nasal tip angle (n-prn-sn) was 99.7±3.4 degrees. The nasolabial angle (prn-sn-ls) was 125.7±4.9 degrees, and the labiomental angle (li-sl-pg) was 131.6±4.4 degrees. The ratio of the upper lip height to the lower lip height (sn-sto/sto-sl) was 85.4±9.0%. The ratio of the upper lip vermillion to the upper lip height (ls-sto/sn-sto) was 27.7±3.9%. The ratio of the lower lip vermillion to the lower lip height (sto-li/sto-sl) was 47.2±6.6%. Comparing the data with 21st-century Italian females, forehead II height (tr-n), physiognomical face height (tr-gn), and morphologic face height (n-gn) of the beauties of the 15th century were significantly greater than those of 21st-century Italian females. However, there were no significant differences in lower face height (sn-gn) and nose height (n-sn). Considering the ongoing cultural relevance of Renaissance art, the esthetic proportions from this study may have reflection to the present day plastic surgery.

Controlling spatial optical illuminations in optogenetics using an angled optical fiber tip

The advent of optogenetic tools has revolutionized neuroscience research through its spatiotemporally precise activation of specific neurons by illuminating light on opsin-expressing neurons. A long-standing challenge of in vivo optogenetics remains in delivering light to multiple brain sites simultaneously and maintaining high spatial resolution. Optical fiber-based technologies have been proposed to address these challenges. This work presents the fabrication and characterization of an innovative angled optical fiber probe based on a double-sided angled tip (DSAT) structure. A custom griding setup was used for the reproducible fabrication of a smooth DSAT probe. The designed probe enables precise spatial control of light propagation in brain tissue in which DSAT at angled tip 55° achieving a maximum lateral illumination position of ± 420 μm away from the optical axis and a peak irradiance of 478.5 mW/mm2, using a 5 mW of 473 nm laser light. Also, the designed DAST probe was simulated based on ray tracing method and obtained the practical tip angle to evaluate the propagation of light rays emitted from the DSAT at various input optical angles ranging from 0° to 12.5° to predict their irradiance and positions in the modelled tissue. The results indicate the probe generates two elliptical rings each containing two spots with higher optical concentration. Consequently, this device provides four optical spots with irradiance peaks that enable simultaneous illumination of four different locations in the brain tissue. Obtained experiment results are in good agreement with simulation results which can be used for multipoint illumination of brain tissue in optogenetics applications.

Computerized Penetrometry Methodology Assisted by Advanced Algorithms Applied in the Multi-Dimensional Analysis of the Rheology of Mold-Ripened Cheeses

The main objective of this study is to understand the rheological behavior of various types of cheeses with mold subjected to multiple stresses during processing/handling, transport, or storage, aiming to maintain or even improve product quality, using computer-assisted penetration methods and advanced regression algorithms. Uniaxial penetration tests with a cone at a constant speed were conducted using a universal Hounsfield testing equipment connected to a computer to analyze the texture behavior (tangential stress, flow index, apparent viscosity) of four of the most common types of cheese with mold depending on the cone’s tip angle (9, 19, and 90 degrees) and penetration speed (12, 30, and 60 mm/min). From the results obtained for the four categories of mold cheeses (Brie, Camembert, Dorblue, and Roquefort), the amplitude of the speed and angle of penetration were considered as the main influencing factors for the shear deformation (τc), flow index (Kf), and apparent viscosity (ηa). The moisture and firmness of mold cheeses are closely linked and depend on the type of mold, the maturation process, or storage conditions. Careful control of these factors is essential to achieve the desired texture and taste characteristics in cheeses with mold.

A retrospective study on different kind of cartilage frameworks on Asian rhinoplasty

BackgroundThe character of Asian nose usually presents low projection of tip, short columellar, and short nose, necessitating the construction of a cartilage framework to achieve optimal results. The objective of this study was to evaluate the structural characteristics, stability, and postoperative outcomes of the integrated fixed framework, 1+1 framework, 2+1 framework, 4+1 framework, and Y-shaped framework. MethodsA retrospective analysis was conducted on a cohort of 612 patients who underwent rhinoplasty and were admitted between February 2017 and December 2022. According to rhinoplasty framework, the patients were categorized into fixed frameworks (integrated fixed framework group, 1+1 framework group, 2+1 framework group) or elastic frameworks(4+1 framework group, Y-shaped framework group). The stability of rhinoplasty frameworks was assessed by measuring nasal tip projection and nasolabial angle at both one and twelve months post-surgery. Postoperative follow-up included monitoring complications occurrence and evaluating patient satisfaction. ResultsThe mean duration of follow-up was 25.23 months (rang from 24 to 54 months). The overall satisfaction rate reached 89.37 %(547/612), with the highest satisfaction rate observed in 2+1 framework group.Compared with the integrated fixed, 1+1, 2+1 framework group, the nasolabial angle and nasal tip projection of 4+1, and Y-shaped framework group decreased more obviously(P < 0.001). ConclusionsNasal frameworks in Asians are generally classified as fixed frameworks or elastic frameworks. The stability of the fixed frameworks surpasses that of the elastic frameworks. The secure fixation of the strut to the anterior nasal spine can enhance the overall stability of the framework. Level of evidence statementIV

Effect of Trailing Edge and Span Morphing on the Performance of an Optimised NACA6409 Wing in Ground Effect

Abstract A CFD investigation was carried out on a three-dimensional NACA6409 wing in ground effect at a Reynolds number of 320,000. Using a Multi-Objective-SHERPA algorithm, a root angle of 4 degrees angle of attack, a tip angle of 6 degrees, a forward sweep and a tip chord of 20% of the root chord produced an optimum aerodynamic efficiency across all ground clearances. Optimisation showed a gain in aerodynamic efficiency of 41% at h/c = 0.05 ground clearance and a 31% gain at h/c = 0.2 compared to a rectangular planform wing. Next FishBAC camber morphing was applied to the optimised wing varying the morphing start locations along the chord at both the tip and root. A later start location produced the highest aerodynamic efficiency but increased manufacturing complexity. Extendable span morphing was also tested and was found increasing the span from 1c to 1.5c increased the aerodynamic efficiency of the optimised wing by 27.4% at h/c = 0.1. Varying the span from 0.8c to 1.2c in ground effect had a small effect on the drag for small ground clearances, for large ground clearances the total drag decreased as the span increased. Smaller gains were seen when the span morphing was applied to the rectangular wing. The FishBAC morphing was applied in the spanwise direction to morph the wing tip, sealing the flow beneath the wing. Also, the proportion of the morphing wing tip caused the trailing edge to be closer to the ground further enhancing ground effect.

Comparison of 1- and 3-piece directly 3-dimensional printed indirect bonding trays: An in vitro study

This study aimed to compare the transfer accuracy of indirect bonding trays of different thicknesses and numbers of pieces. Digital indirect bonding was performed on 56 printed resin models, divided into 4 groups with 14 models in each: 1-mm 1-piece tray (OPT), 2-mm OPT, 1-mm 3-piece tray (TPT), and 2-mm TPT. The trays were designed using Appliance Designer (3Shape A/S, Copenhagen, Denmark). Angular (torque, tip, or angulation) and linear (mesiodistal, buccolingual, occlusogingival, or vertical) differences were compared by using open-source GOM Inspect software (GOM GmbH, Braunschweig, Germany). In the buccolingual direction, the 1-mm TPT (0.180 ± 0.041 mm) was significantly more accurate than the 1-mm OPT (0.240 ± 0.032 mm). In the vertical direction, significant differences were seen between the 1-mm and 2-mm OPTs (1-mm OPT: 0.220 ± 0.043 mm; 2-mm OPT: 0.428 ± 0.143 mm; P= 0.003) and between the 1-mm and 2-mm TPTs (1-mm TPT: 0.210 ± 0.072 mm; 2-mm TPT: 0.340 ± 0.062 mm; P= 0.004) in the total region. In the tip angle, significant differences were seen between the 1-mm and 2-mm OPTs and between the 1-mm OPT and TPT. In the torque angle, a significant difference was seen between the 1-mm TPT (2.815°±0.350°)and 2-mmTPT (2.368° ± 0.245°; P= 0.017). Both the thickness and the splitting of the trays impacted the bracket bonding accuracy. The 1-mm trays were more accurate than the 2-mm trays. Despite a few statistically significant differences between the 1-mm OPT and TPT, the 1-mm OPT was recommended for clinical use, considering the designing and placing of the trays.