Vertical Axis Research Articles

Analysis of the Dispersive and Distributive Mixing Effect of Screw Elements on the Co-Rotating Twin-Screw Extruder with Particle Tracking

Compounding is an important step in processing base polymers and is used to incorporate various additives into a polymer. For this purpose, different screw elements are used for dispersive and distributive mixing on a co-rotating twin-screw extruder. Optimising the screw configuration requires precise knowledge of the screw elements’ mixing properties, which have not been thoroughly investigated. This study analyses the mixing behaviour of individual screw elements regarding dispersive and distributive mixing using 3D CFD flow simulations with subsequent particle tracking. For distributive mixing, the particle distribution behind the screw elements in the XY plane is analysed and the mixing index MQ, which relates the standard deviation and the mean value of the triangular areas between the particles, is calculated. For dispersive mixing, the maximum shear stress on the particle path and the integral of the shear stress over the residence time of each individual particle are determined. The results show that screw element geometry and rotation speed have a significant influence on dispersive and distributive mixing. In addition, better dispersive mixing is achievable with highly viscous materials. These findings enable the optimisation of the mixing zone of a co-rotating twin-screw extruder for the efficient mixing of mineral fillers.

Inquiry as Resonance: Wiry Workings of Failure and Patience

In this article, I offer inquiry as resonance, an axiological inquiry practice that seeks to amplify transformative resonances in the world. This inquiry practice gets to work with Rosa’s modes of resonance that include the qualities (i.e., af<-fection, e->motion, transformation, and uncontrollability) as well as horizontal (i.e., human actors), vertical (i.e., art, history, and the like), and diagonal (i.e., structural and ideological entities) axes that create resonances between a human actor and the interconnected world in which they live. Inquiry as resonance advocates for an accountable “I” in an interconnected and shifting world. I came to inquiry as resonance through a journey of failure (or lack of resonance) with theory and patiently writing and working with, though, and against that failure. That journey created space for me to consider resonance and what an inquiry of resonance might look like.

Combined genetic algorithm and response surface methodology‐based bi‐optimization of a vertical‐axis wind turbine numerically simulated using CFD

AbstractIn this study, computational fluid dynamic (CFD) simulation of a vertical axis wind turbine (VAWT) geometry based on the Unsteady Reynolds–Averaged Navier–Stokes equations was investigated. In addition, the relationship between the geometric parameters of the VAWT and the two response variables, that is, moment and lift force, was determined using response surface methodology (RSM). Then, the Non‐Dominated Sorting Genetic Algorithm (NSGA‐II) was used to solve the multi‐objective optimization problem. The results obtained from the RSM showed that the lift force of the turbine is more sensitive to the change in the blade chord length, and the output moment of the turbine is more sensitive to the change in the rotor radius. Using the NSGA‐II multi‐objective optimization algorithm and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method, it was determined that among the optimal values of the independent variable, the most optimal response occurs in blade chord length = 0.18 m, rotor radius = 0.4 m, blade pitch angle = −3.27° and number of blades = 4. In these optimal values of the independent variables, the values of the dependent variables, which included the turbine's moment and the blades’ lift force, were obtained as 9.58 N m and 57.89 N, respectively.

Influence of Solution Treatment Temperatures on LPBF-Produced Inconel 939 Alloy on Mechanical Performance

This study investigates the influence of solution treatment temperatures on the microstructure and mechanical properties of LPBF (Laser Powder Bed Fusion)-manufactured Inconel 939 alloy. The primary objectives are to assess the impact of sub-recrystallization (below recrystallization temperature) and recrystallization temperatures during solution treatment on mechanical performance under different conditions. This study validates the hypothesis concerning carbide redistribution and mechanical performance in LPBF-produced Inconel 939 parts through comprehensive analysis, including microstructure studies and tensile tests. The results indicate that higher heat treatment temperatures lead to significant changes in carbide redistribution and mechanical performance. For instance, at room temperature, the specimen with sub-recrystallization solution treatment temperature exhibited superior mechanical properties compared to both the as-built and recrystallization-temperature solution treatment specimens. However, at elevated temperatures (700 °C), a reversal in mechanical anisotropy was observed, with the vertical axis demonstrating higher tensile strength compared to the horizontal axis for all material states. Furthermore, a microstructural analysis revealed distinct changes in grain structure and precipitate distribution, particularly the migration of carbides from grain boundaries to intragranular regions. These findings underscore the importance of precise control over heat treatment parameters to achieve optimal mechanical behavior. This research provides valuable insights into optimizing LPBF processes for the Inconel 939 alloy, highlighting the need for a meticulous control of the solution treatment parameters to ensure mechanical integrity. The findings contribute to a broader understanding of material-specific responses in additive manufacturing, with significant implications for aerospace applications.

Undervalued role of metal-carbon junction in selective generation of H2O2: An example of the zinc-carbon junction edge providing asymmetric active sites for efficient oxygen reduction

The spontaneous oxygen reduction is a potential technology for in-situ H2O2 production, which gets rid of the dependence on electricity and solar energy. Previous some metal–carbon compounds reported are feasible to trigger oxygen reduction. These reports always claim the high H2O2 generation ability of metal–carbon composites, while rarely discuss the contribution of carbon and the carbon–metal junction to the oxygen reduction process. Inspired by the dual active sites, we infer that the role of interfacial carbon in metal–carbon composites is underestimated. By a heat treatment of the co-precipitate of zinc and glucose, the Zn-C junction is constructed in Zn-gc to achieve a spontaneous selective reduction of O2 to H2O2. The Zn-C interface edge is active site, where an asymmetric activation is achieved by bonding two O atoms from O2 to C and Zn, respectively. The Zn traction to one of the O atoms is mainly in xy plane, while the C traction to the other O atom is parallel to z-axis. The yield of H2O2 produced per gram of Zn increases from 27.89 mg to 122.21 mg, an improvement of 4.38 times. And the inertness of Zn and its oxygen-containing compounds towards H2O2 enables Zn-gc/O2 system to stabilize H2O2 over a long period of time. This work reveals the crucial role of neglected junction interfaces in oxygen reduction reactions in metal–carbon composites.

K-means for earthquakes: disaggregation analyses of small events by considering wave components and soil types

AbstractIn this paper, k-means algorithm has been used to disaggregate seismic parameters to evaluate their inter-correlations. A goal is to quantify in a disaggregated way the weights and effects of each parameter with respect to other ones. From the database, about 4900.0 data, divided into 22.0 categories, have been collected. The main divisions regard the wave components in horizontal and vertical axis and the soil characteristics. The studied seismic zone is the “Norpirenaica oriental,” placed in the Pyrenees area between Spain and France, classified as a very high seismic hazard. Numerical and analytical analyses have been carried out to implement the algorithm. Preliminary analyses and results would quantify the role of the sand horizontal stratigraphy, the non-linear effects, the elasticity of the soil, and the energy damping phenomenon. Curves are plotted in stochastic distributions and elastic spectra accelerations. Results show good prediction for vertical spectral accelerations and for far and relative strong events. Rigorously, results are valid only for the studied seismogenic zone under predefined constrictions and ranges.

Morphological observation of occipital condyle position in Chinese skulls and potential clinical significance.

To study the anatomy of the Chinese occipital condyle and its position relative to the occipital foramen and skull. Measurements were taken from 106 adult Chinese skulls using a Cartesian coordinate system centered on the foramen magnum. Measurements included the longitudinal diameter of the foramen magnum, distances from various points on the occipital condyles to the foramen magnum and skull landmarks, and the occipital condyle classification index (OCI) and skull-occipital condyle classification index (SOCI). OCI categorized the position of the foramen magnum and occipital condyles into three groups: OCI ≤ 0.40 (3 cases, 2.83%), 0.40 < OCI ≤ 0.50 (75 cases, 70.75%), and OCI > 0.50 (28 cases, 26.42%). SOCI categorized the relationship between the skull and occipital condyles into two groups: 0.5 < SOCI ≤ 0.6 (49 cases, 46.23%) and 0.6 < SOCI ≤ 0.7 (57 cases, 53.77%). Four relationship types were identified based on specific measurements: Type I (23 cases, 21.70%), Type II (42 cases, 39.62%), Type III (4 cases, 3.77%), and Type IV (37 cases, 34.91%). Sagittal movement of the occipital condyle affects the cervical spine's curvature. Asymmetry between the occipital condyles and the foramen magnum may misalign the skull with the body's coronal plane.

On the non-flatness nature of noncommutative Minkowski spacetime and the singular behavior of probes

It is more than a century-old concept that the Minkowski spacetime is flat. From the pure geometric point of view, we explicitly address the issue of whether a noncommutative Minkowski spacetime is flat or not. In the framework of the twisted-diffeomorphism approach to noncommutative gravity with canonical type noncommutative (NC) coordinate structure, one important result that we get is that the NC Minkowski spacetime parametrized either with spherical polar coordinates or with parabolic coordinates has nontrivial NC corrections to Riemann curvature tensor, Ricci tensor and curvature scalars. Another crucial result is that the curvature scalars have singular behavior at certain points, and these singularities are not coordinate singularities. The nature of these singularities clearly points towards the idea of high-energetic probes turning into black holes. The absence of any such noncommutative corrections, and thus any such singularities, in the cases of Cartesian coordinates and cylindrical coordinates leads to the conclusion that high-energetic probes do not turn into black holes when the canonical NC structure is considered for these coordinates.

Smart PDOs™ and the Cartesian Technique™: A milestone in facial rejuvenation with bioactive scaffolds

Objectives: Evaluate the controlled release of silicon from smart polydioxanone suture (Smart PDOs™) and the clinical effect of the Cartesian Technique™ in face lifting. Material and Methods: This study was preclinical and clinical trials randomized, uncontrolled, and phase I carried out. Preclinical trials included instrumental analysis of silicon-enriched sutures by light microscopy, electron microscopy, and Ultraviolet-visible (UV-vis) spectroscopy. The clinical trial included 35 patients with primary and secondary rhytides, grade I lipomatosis, and grade I deflation. Polydioxanone (PDO) sutures are inserted following the Cartesian Technique™, a vectorial lift from the intersection of the Cartesian planes of the face. Once the cannulas were inserted with the PDO thread, 0.1 mL of organic silicon was dosed. Turgidity was examined by the pinch test of skin turgor. To measure the position of flaccid or deflated tissues, the scale used was the deflation scale. Results: The controlled release of organic silicon from the PDO sutures was verified. Its clinical application revealed that after 8 days the improvement in turgidity, wrinkle reversal, and flaccidity tightening was maintained in 100% of the sample. At 15 days, reversal of rhytides was observed, softening of deep furrows in 80%, and the initial turgor and skin tightening maintained without deflation in 90% of cases. Histopathological findings reveal that silicon synergistically potentiates the tissue effect of the PDO suture, generating greater biostimulation of fibroblasts with better quality collagen fibers, greater restructuring and redensification of the skin, and avoiding the late inflammatory response. Conclusion: The Cartesian Technique™ with Smart PDOs™ is an effective protocol for skin replenishment that enhances cell biostimulation through the release of bioactive drugs.

Determination of Load Forces on the Upper Part of Orthopedic and Postoperative Shoes

Determined patterns of force load on the sole and upper of orthopedic and postoperative shoes when bending the foot while walking. To determine the force of the load on the top of the postoperative orthopedic shoes, the frictional forces between the lateral surfaces of the shoes and the outer lateral sides of the foot can be neglected. Thus, the task will be reduced to the compilation of equilibrium equations of a plane system of forces. As can be seen from the load diagram of the top of the shoe, we have a flat arbitrarily located system of forces. To determine the unknown forces, it is necessary to compile a system of two equilibrium equations, which will represent the algebraic sums of the projections of all forces on the horizontal and vertical axes. To automate the design process of orthopedic and postoperative shoes, a computer program was developed that allows you to perform calculations of the corresponding forces and tension depending on the design and types of material of individual elements, as well as obtain regression equations for determining the effect of tension on the magnitude of the detachment force.

Proposal of UAV-SLAM-Based 3D Point Cloud Map Generation Method for Orchards Measurements

This paper proposes a method for generating highly accurate point cloud maps of orchards using an unmanned aerial vehicle (UAV) equipped with light detection and ranging (LiDAR). The point cloud captured by the UAV-LiDAR was converted to a geographic coordinate system using a global navigation satellite system / inertial measurement unit (GNSS/IMU). The converted point cloud is then aligned with the simultaneous localization and mapping (SLAM) technique. As a result, a 3D model of an orchard is generated in a low-cost and easy-to-use manner for pesticide application with precision. The method of direct point cloud alignment with real-time kinematic-global navigation satellite system (RTK-GNSS) had a root mean square error (RMSE) of 42 cm between the predicted and true crop height values, primarily due to the effects of GNSS multipath and vibration of automated vehicles. Contrastingly, our method demonstrated better results, with RMSE of 5.43 cm and 2.14 cm in the vertical and horizontal axes, respectively. The proposed method for predicting crop location successfully achieved the required accuracy of less than 1 m with errors not exceeding 30 cm in the geographic coordinate system.

Study of substituents-regulated dyeing properties in non-aqueous media systems based on MD simulation and DFT

To investigate the relationship between N-acetoxyethyl group and dyeing properties of disperse dyes in D5 non-aqueous medium dyeing system, the adsorption and diffusion behaviors of three disperse dyes with different structures were studied by molecular dynamics (MD). The diffusion coefficients, the planar distribution densities of dyes in different directions, and the intermolecular interaction energies were calculated. Molecular dynamics simulation (MD) was used to calculate molecules polarity index (MPI). Meanwhile, the practical dyeing experiments also were investigated to compare with simulated results. The results showed that the adsorption and diffusion behavior of disperse dyes with different structures were significantly different. Compared with dye B257, D-1 and D-2 are more easily adsorbed and diffused into the interior of the fiber because of the introduction of polar acetoxyethyl group. Moreover, the diffusion coefficient of D-2 in the fiber was relatively low, indicating that the combination between dye and polyester fiber was stable. XY plane distribution density and MPI revealed that the introduction of acetoxyethyl was beneficial to increase the adsorption amount of dye on the fiber, which was mainly related to the high binding energy between dye molecule and polyester fiber. The results of dyeing experiments showed that the decreased solubility of disperse dyes in the D5 medium was conducive to improving the dyeing rate of disperse dyes. This was consistent with the simulated interaction between dyes and D5. This study will provide a basis for further rapid and accurate development and selection of disperse dyes with high dyeing rate in non-aqueous medium systems.

Evaluation of the sagittal vertical axis with postural and 3D motion analyses in lumbar spinal stenosis

BackgroundSagittal balance, commonly impaired in lumbar spinal stenosis (LSS) patients, is typically assessed using the sagittal vertical axis (SVA) with EOS imaging. However, to limit X-ray exposure and medical costs, it could be interesting to evaluate the capacity of quantified motion analysis to estimate the 3D modeling of SVA in patients with symptomatic LSS.MethodsAn estimation of the SVA in patients with LSS was performed with 3D motion analysis. SVA and “C7_PSI” (orthogonal horizontal distance between the vertical lines through the markers of the C7 vertebra and the middle of the posterosuperior iliac spine) were measured on 37 LSS patients using EOS radiography and postural and 3D motion analysis, respectively. Multiple stepwise linear regressions were performed with EOS SVA according to age, body mass index, C7_PSI and/or postural variables.ResultsA highly significant relationship was found between SVA and C7_PSI, mediolateral amplitude of CoP displacements and age (adjusted R²=0.69, p < 0.0001). While the postural analysis did not reveal significant relationships, the model using 3D parameters revealed significant relationships between radiographic SVA and C7_PSI and age (adjusted R²=0.65, p < 0.0001). 3D motion parameters with or without postural parameters may explain more than 65% of the variance seen in EOS imaging performed on LSS patients.ConclusionsThese promising results in LSS patients suggest that the estimation of SVA with 3D motion analysis offers an alternative to EOS. In addition, SVA could be assessed at rest and during dynamic tasks.Trial registrationThis study has been published in Clinical Trial registration (reference NCT03194607).

Recovery of electrical power from exhaust air—role of vertical axis wind turbine

AbstractThis article explores the potential of regeneration of power from unnatural wind sources with the help of vertical axis wind turbines (VAWT). Researchers are searching for urban as well as industrial wind sources, which can be useful as the natural wind source to obtain electrical energy and utilize it. The wind sources considered here are the exhaust of the cooling or ventilation fans used in buildings, industries, and other places. The Darrieus VAWT extracts wind power from the exhaust air and reduces the power consumption of the concerned electrical drives. These uncommon energy sources have an inherent capability to recover a significant amount of energy without polluting the environment with less payback period. Recovered energy can be suitably converted into electrical energy and may be fed back to the power grid without any pollution, thus minimizing the total energy consumption of the building and reducing the cost operations. A detailed study of experimental models with different types of assembly and turbine models is conducted here with power outputs and operational behaviors on the existing systems. Various parameters and factors for existing and new applications are in detail that show the system has no negative impact on regular operation.

Control of spin-wave polarity and velocity using a ferrimagnetic domain wall

We present a theoretical study of the scattering of spin waves by a domain wall (DW) in a ferrimagnetic (FiM) spin chain in which two sublattices carry spins of unequal magnitudes. We find that a narrow but atomically smooth FiM DW exhibits a different behavior in comparison with similarly smooth ferromagnetic and antiferromagnetic DWs due to the inequivalence of the two sublattices. Specifically, for sufficiently weak anisotropy, the smaller spin at the center of the DW is found to become precisely normal to the easy axis, selecting an arbitrary direction in the xy plane and thereby breaking the U(1) spin-rotational symmetry spontaneously. This particular form of a FiM DW does not occur in antiferromagnetic systems and is shown to lead to a strong dependence of spin-wave scattering pattern on the state of polarization of the spin wave, which can be either right-handed or left-handed, suggesting the utilization of such a narrow DW as a spin-wave filter. Moreover, we find that in the case of an atomically sharp DW, where all the spins point either up or down due to strong easy-axis anisotropy and therefore the polarization of the spin wave is conserved upon transmission, the wave vector of the spin-wave changes after passing through the DW leading to a change in the group velocity of the spin wave. This change of the wave vector indicates the acceleration or deceleration of the spin waves and thus a sharp FiM DW could serve as a spin-wave accelerator or decelerator in spintronics devices, offering a functionality absent in a ferromagnetic and an antiferromagnetic counterpart. Our results indicate that FiM spin textures can interact with spin waves distinctly from ferromagnetic and antiferromagnetic counterparts, suggesting that they may offer spin-wave functionalities that are absent in more conventional magnets. Published by the American Physical Society 2024

Assembly method for curved porous circular workpieces based on multidimensional information fusion: Grid electrode component

To tackle the problems related to the complexities of obtaining depth information for circular workpiece with arc surface and holes, a novel vision guidance method has been introduced to precisely gauge interlayer spacing. The process includes the acquisition and preprocessing of point cloud depth information, along with matching and edge processing. The depth coordinates of the point cloud are subsequently determined. Two-dimensional image processing technology is employed to extract the coordinates of the center of the surface circular hole in the curved porous circular workpiece. The 3D coordinates are generated for guiding the assembly by integrating these datasets. Experiments on grid parts in aviation propulsion systems demonstrate that this method maintains dot matrix spacing within 0.5–1.2 mm, ensures the coaxiality of the center hole, and meets assembly standards. The results confirm the method’s effectiveness for automated assembly of curved porous round workpieces.

A Practice of City-scale 3D Geographic Entity Representation and Application in China: The Smart Chongqing City Centre

Abstract. The Chinese photogrammetry industry is currently experiencing a significant revolution driven by digital intelligence technologies. Traditional city-scale 3D modelling, typically reconstructed from oblique photogrammetry or laser points, is facing increasing limitations in refined expression, real-time rendering, machine recognition, data sharing, and interoperability due to its large data volume and mesh structure. These limitations make it difficult to meet the substantial demands of spatial analysis, simulation, and prediction. The concept of geographic entities, which are machine-recognizable spatial data structures, is anticipated to provide a competitive solution for these challenges. This work employs 3D scene modelling and geographic knowledge graphs to construct geographic entities with semantic relationships at city-scale, addressing the limitations encountered in the application of traditional mesh/point-based 3D models. A case study in Chongqing city centre demonstrates the feasibility and effectiveness of the proposed approach and its potential applications in simulation, prediction, early warning, and feedback for urban planning and smart city management.

Functionality of Bearings in the Shafts of a Vertical-Axis Wind Turbine

The article contains a description of the design solutions proposed by the authors for a hybrid wind turbine bearing, in which the sliding part takes over the load to the turbine shaft after reaching the shaft rotation speed, ensuring hydrodynamic lubrication of the plain bearing and relieving the rolling bearing. This allows for low starting resistance of the power plant and ensures quiet operation during use. Two conceptual solutions of a hybrid bearing were presented, differing in the shape of the plain bearing journal. A mechanism for automatic switching of the load between a rolling and a plain bearing was developed. A solid simulation model of this mechanism was built in the Autodesk Inventor—Dynamic Simulation software Inventor Professional 2023 environment, and its operation was simulated. The results confirmed the usefulness of using this design in shaft-bearing systems of wind turbines with a vertical axis of rotation. Based on the simulation, the speed at which the thrust roller bearing will be released was determined. Technical parameters of a plain bearing with a spherical journal shape were calculated. The height of the lubrication gap and the shaft rotational speed at which the bearing load capacity index reaches a critical value were determined.

Multidisciplinary teaching with an active video game: the effect on learning in mathematics and physical education

ABSTRACT Practising active video games (AVGs) requires performing motor and cognitive tasks, which might foster success in physical education and other school subjects but remains poorly investigated. This study examined the learning effects of six lessons using AVGs with physical education and mathematics content. Overall, 216 school-students composed an experimental group (n = 99) and a control group (n = 107). Both attended six lessons, each on using a Cartesian coordinate system and ball-throwing accurately, with AVGs in the experimental group only. Learning was assessed at Lessons 1 and 6, situational interest and moderate-to-vigorous physical activity (MVPA) at Lessons 3 and 5. MANOVAs showed no between-group differences in situational interest and higher MVPA for the control group at Lesson 3 only. Statistical analysis showed higher learning scores (mathematics and physical education) for the experimental group at Lesson 6, suggesting possible interest in AVGs during multidisciplinary sequences connecting physical education and mathematics.

Axes-aligned non-linear optimized PnP algorithm

Pose estimation is an important component of many real-world computer vision systems. Most existing pose estimation algorithms need a large number of point correspondences to accurately determine the pose of an object. Since the number of point correspondences depends on the object’s appearance, lighting and other external conditions, detecting many points may not be feasible. In many real-world applications, the movement of objects is limited, e.g. due to gravity. Hence, detecting objects with only three degrees of freedom is usually sufficient. This allows us to improve the accuracy of pose estimation by changing the underlying equations of the perspective-n-point problem to three variables instead of six. By using the simplified equations, our algorithm is more robust against detection errors with limited point correspondences. In this article, we study three scenarios where such constraints apply. The first one is about parking a vehicle on a specific spot. Here, a stationary camera is detecting the vehicle to assist the driver. The second scenario describes the perspective of a moving camera detecting objects in its environment. This scenario is common for driver assistance systems, autonomous cars or mobile robots. Third, we describe a camera observing objects from a birds-eye view, which occurs in industrial applications. In all three scenarios, observed objects can only move in the ground plane and rotate around the vertical axis. Hence, three degrees of freedom are sufficient to estimate the pose. Experiments with synthetic data and real-world photographs have shown that our algorithm outperforms state-of-the-art pose estimation algorithms. Depending on the scenario, our algorithm is able to achieve 50% better accuracy, while being equally fast.