Rotation Angle Research Articles

The aortic-vertebral distance is more associated with axial plane deformities than coronal and sagittal deformities in idiopathic scoliosis patients of Lenke types I and II.

Although idiopathic scoliosis is a common three-dimensional deformity, there is a lack of studies evaluating the associations between the aortic-vertebral distance (AVD) and spinal deformities in all planes. The study therefore aimed to evaluate how the coronal and sagittal curvature, vertebral rotation and aortic-vertebral angle (AVA) affect the AVD in idiopathic scoliosis. The AVD, AVA, vertebral rotation and curve angles were measured on preoperative magnetic resonance imaging and radiographs in 46 patients who underwent posterior spinal fusion with pedicle screw instrumentation for idiopathic scoliosis Lenke types 1 and 2. Associations between variables were examined using correlation and multivariable regression analyses. A significant weak to strong correlation was found between the AVD and AVA, and the AVD and vertebral rotation (r = 0.315 to 0.712) within the thoracic curve. The sagittal kyphosis and coronal Cobb angles showed weak correlations with the AVD (r = -0.311 to 0.338). The regression model for the apical vertebral level, which included the four variables, explained 40% (R²=0.40) of the variation in AVD. AVA and vertebral rotation were significantly associated with AVD (p < 0.01 for each), together accounting for 34% (R²=0.34) of the variation. The shortest distance from the aortic wall to the vertebral body wall is primarily influenced by vertebral rotation and the AVA within the thoracic curve. Thus, these factors need to be taken into consideration when planning pedicle screw placement especially in freehand techniques.

The optimal control law of the power supplied to the wheeled vehicle in case of curvilinear movement

INTRODUCTION: Highly mobile wheeled vehicles are designed to move on roads and terrain in various road and soil conditions, which is accompanied by frequent and significant changes in traction forces and rolling resistance forces. In this regard, in order to maintain vehicle mobility and ensure low energy costs when performing transport tasks, it is necessary to continuously change the operating mode during movement from completely locked to differential in the case of a mechanical transmission. At the same time, the transmission operating mode selected by the driver is not always rational. Thus, the development of a law for controlling the power supplied to the propulsion system, ensuring minimal energy losses while maintaining vehicle mobility in widely varying road conditions, is an urgent task. PURPOSE OF THE STUDY: Increasing the energy efficiency of highly mobile wheeled vehicles by applying a control law for the power supplied to the propulsion system, adaptive to driving conditions. METHODOLOGY AND METHODS: Increasing the energy efficiency of movement can be achieved by reducing losses due to wheel slipping by controlling the power supplied to the propulsion unit. It is advisable to obtain the control law as a result of solving an optimization problem, where the loss power is chosen as the objective function, and the traction forces developed on each of the wheels are chosen as the varied values. At the same time, in order to maintain the possibility of vehicle movement, it is necessary to take into account that the total traction force on all wheels must be determined by external conditions and provided by the power plant. To solve the optimization problem, the Lagrange multiplier method was used. RESULTS AND SCIENTIFIC NOVELTY: The studies carried out made it possible to obtain in analytical form a unified law of adaptive control of the power supplied to the propulsors, applicable in a wide range of road conditions in both straight and curved motion, providing a close to optimal distribution of moments across the driving wheels of the machine, obtained as a result of numerical optimization. PRACTICAL SIGNIFICANCE: The application of the developed law for controlling the power supplied to the propulsors, based on the use in the process of movement of information only about the longitudinal and vertical forces, rotational speeds and angles of rotation of the wheels (trajectory radius), will improve the efficiency of performing transport tasks when moving a vehicle in continuously changing road conditions due to reducing the load on the driver in terms of controlling differential locks in comparison with a manual transmission both in straight and curved motion.

Photonic scheme to generate frequency 24-tupling mm-wave signal using three cascaded polarization modulators without filters

Abstract The paper proposes a new scheme for generating a frequency 24-tupling millimeter-wave (mm-wave) signal using three cascaded polarization modulators (PolMs). In the scheme, three polarization modulators with the cooperation of polarization controller (PC) and polarizer (Pol) in each subsystem are first employed to produce even order optical sidebands. Adjusting the angle of electrical phase shifters (EPS) to eliminate the unwanted even order optical sidebands except (6n)th order optical sidebands. Next, setting the modulation index to 4.968 to eliminate ±6th order sidebands. At last, adjusting the rotation angle of the polarizer placed behind the polarization beam combiner (PBC) to suppress 0th order optical carrier from the upper and lower branches. The obtained pure ±12th order sidebands are fed into the photodiode (PD) beat frequency. After detailed mathematical derivation and simulation verification, the accuracy of the scheme has been verified. The simulation results show that the optical sideband suppression ratio (OSSR) and the radio frequency spurious suppression ratio (RFSSR) can reach 54.49dB and 43.86dB, respectively. Moreover, the impacts of these non-ideal elements on OSSR and RFSSR are analyzed, and an admissible error extent is listed.&amp;#xD;

The effect of blade turning angle on rotation improvement of a small horizontal axis wind turbine

Optimization of wind turbine aerodynamic performances implies solving the problem in the domains such as airfoil selection, blade rotation angle, chord optimization, number of blades, appropriate tip speed ratio, etc. The current paper studies the effect of blade rotation angle [Formula: see text] on power coefficient [Formula: see text], torque [Formula: see text] and mechanical power [Formula: see text] in a small horizontal axis wind turbine ( HAWT). The analysis involves two models of blades ( V and) of the airfoil class SD 7003. The first part of the paper employs numerical analysis, that is, Ansys CFX and Ansys Fluent software packages, to define wind turbine characteristics. The obtained results indicate that as the rotation angle [Formula: see text] increases the [Formula: see text] increases within an appropriate range of tip speed ratio [Formula: see text] change. The second part describes experimental investigation conducted on considered HAWT to define the values of [Formula: see text] and [Formula: see text] for studied blade rotation angles and comparison with the values obtained from Ansys. Existing differences in values are a consequence of the design of the HAWT, that is, the influence of the mass moment of inertia of the rotor and generator as well as the placement of the generator. Experimental setup and methodology allow for investigating the effect of different blade models, rotor and generator structure on wind turbine torque and mechanical power output characteristic.

Log End Face Feature Extraction and Matching Method Based on Swin Transformer V2

This study proposes a novel log end face feature extraction and matching method based on Swin Transformer V2, aiming to address limitations in accuracy and speed faced by traditional deep learning models, like InceptionResNetV2 and Vision Transformer. Accurate log identification is crucial for forestry and wood supply chain management, especially given the growing reliance on timber imports to meet industrial demands in construction, furniture manufacturing, and paper production. Our dataset comprises images of coniferous timber, specifically Scots pine (Pinus sylvestris L.), reflecting its significance as an essential imported resource in China’s timber industry. By leveraging Swin Transformer V2 as the backbone, our method enhances feature extraction and achieves a significant accuracy improvement from 84.0% to 97.7% under random rotation angles while reducing the average matching time per log to 0.249 s. The model was evaluated under fixed and random rotation augmentations, and the results demonstrated Swin Transformer V2’s superior clustering ability, as confirmed by t-SNE visualization. Unlike InceptionResNetV2, the proposed model maintains high accuracy and efficiency even as the feature database size increases, making it suitable for large-scale applications. This approach provides a more accurate and efficient solution for log end-face recognition, supporting the development of high-throughput wood identification systems critical for forestry automation and the global timber trade.

Rotation angle between the femoral and tibial components in varus/valgus stress X-rays following total knee arthroplasty

Rotation angle between the femoral and tibial components in varus/valgus stress X-rays following total knee arthroplasty

Evaluating pelvic rotator strength: Investigating asymmetry and its correlation with pelvic rotation angle during active straight leg raise

Evaluating pelvic rotator strength: Investigating asymmetry and its correlation with pelvic rotation angle during active straight leg raise

Programmable Magnetic Hysteresis in Orthogonally-Twisted 2D CrSBr Magnets via Stacking Engineering.

Twisting 2D van der Waals magnets allows the formation and control of different spin-textures, as skyrmions or magnetic domains. Beyond the rotation angle, different spin reversal processes can be engineered by increasing the number of magnetic layers forming the twisted van der Waals heterostructure. Here, pristine monolayers and bilayers of the A-type antiferromagnet CrSBr are considered as building blocks. By rotating 90 degrees these units, symmetric (monolayer/monolayer and bilayer/bilayer) and asymmetric (monolayer/bilayer) heterostructures are fabricated. The magneto-transport properties reveal the appearance of magnetic hysteresis, which is highly dependent upon the magnitude and direction of the applied magnetic field and is determined not only by the twist-angle but also by the number of layers forming the stack. This high tunability allows switching between volatile and non-volatile magnetic memory at zero-field and controlling the appearance of abrupt magnetic reversal processes at either negative or positive field values on demand. The phenomenology is rationalized based on the different spin-switching processes occurring in the layers, as supported by micromagnetic simulations. The results highlight the combination between twist-angle and number of layers as key elements for engineering spin-switching reversals in twisted magnets, of interest toward the miniaturization of spintronic devices and realizing novel spin textures.

Biomechanical coordination and variability alters following repetitive movement fatigue in overhead athletes with painful shoulder

Most sports and leisure activities involve repetitive movements in the upper limb, which are typically linked to pain and discomfort in the neck and shoulder area. Movement variability is generally expressed by changes in movement parameters from one movement to another and is a time-dependent feature of repetitive activities. The purpose of this study was to examine the effect of repeated movement-induced fatigue on biomechanical coordination and variability in athletes with and without chronic shoulder pain (CSP). In this controlled laboratory study, 24 overhead athletes in two groups of athletes with (N = 12) and without (N = 12) CSP were recruited. Biomechanical and Electromyographical data were recorded while the athletes were asked to perform repeating reaching tasks (RRT). Kinematic data was recorded every 30 s of the minutes of the repetitive pointing task (RPT). The kinematic and electromyography data were recorded at the first 30 s of “Fatigue-Terminal” (FT) and the last 30 s of “No-Fatigue” (NF) in the repetitive pointing task (RPT). Raw data was analyzed by using MATLAB code to extract the relevant coordination and movement variability data. Different fatigue conditions led to significant kinematic changes during the repetitive pointing task. In the CSP group, trunk lateral flexion decreased after fatigue, while it increased in the CON group (p < 0.013). Trunk rotation and shoulder elevation angles were smaller before fatigue than after in both groups (p < 0.001). Variability in joint angles, including trunk lateral flexion and elbow flexion, increased after fatigue, indicating less stability in movement patterns (p < 0.001). The coordination between trunk movement and shoulder elevation was altered post-fatigue, with significant changes in EMG variability for muscles like the Lower Trapezius and Long Head of the Biceps (p < 0.001). Results of our study indicate that both groups were able to accomplish fatigue, but they employed different movement strategies. The CSP group primarily focused on controlling the shoulder joint, while the CON group utilized both the shoulder and elbow joints in their strategy. This difference suggests that individuals in the CSP group who experienced chronic pain may have developed a strategy to minimize pain and fatigue during the task. Specifically, the CSP group’s approach appeared to involve adjustments in movement patterns to manage the task despite fatigue. This adaptation contrasts with the CON group’s more complex movement strategy, which involved greater variability and adjustments in both the shoulder and elbow joints.

Rotational Stability and Outcomes of V4c Toric Implantable Collamer Lenses Placed at Different Lens Orientations.

To evaluate the 12-month rotational stability and outcomes of V4c toric Implantable Collamer Lenses (TICLs) (STAAR Surgical) located at two different lens orientations (horizontal or oblique). This retrospective study included a total of 403 eyes with TICL implantation, enrolled between January 2021 and December 2022, that were divided into two groups based on the minimum intended angle off the horizontal axis: horizontal with 263 eyes at an angle ±22.5 degrees or less and oblique with 140 eyes at a minimum intended angle of greater than ±22.5 degrees. A comparison was made of the preoperative characteristics, surgical outcomes, secondary surgical interventions, footplate positions, and adverse events at 1, 6, and 12 months postoperatively. The rotation-related factors were analyzed. At 12 months, there were 243 eyes (92%) in the horizontal group and 130 eyes (93%) in the oblique group that were within ±0.50 diopters (D) of emmetropia. Their rotation proportion was 5.3 % and 5.7%, respectively, and their rotation angle was 9.11 ± 2.84 and 9.96 ± 2.42 degrees, respectively (P = .086). TICL footplates were mostly positioned on the ciliary body. No correlation was observed of lens placement axis, vault, or manifest refraction with rotation in both groups (P > .05). During the follow-up, no vision-threatening complications were observed in both groups. Rotation cases were successfully addressed via alignment or lens exchange. TICLs, when implanted across a range of lens orientations, demonstrated favorable rotational stability and postoperative outcomes. The postoperative rotational stability is independent of the placement angle of the TICL. [J Refract Surg. 2025;41(1):e29-e38.].

Behavior of a mobile robot with symmetrical structure of mecanium wheels when movement along a curvolinear trajectory

The article presents a comparative analysis of two variants of symmetrical placement of omnidirectional mecanum wheels in a mobile robot. The modeling of the mobile robot behavior with two symmetrical variants of mecanum wheel arrangement along curvilinear trajectories in the MATLAB Simulink environment is considered. Graphs of the robot center trajectories in the X–Y axes are obtained for two variants of symmetrical mecanum wheel configurations when moving along the trajectories of a lemniscate, ellipse, hypotrochoid, and track. Dependences of the robot position errors in the X–Y axes on time are obtained for two variants of wheel topologies when moving along four trajectories. Dependences of the robot body rotation angle deviation on time are analyzed for two variants of wheel topologies when moving along four curvilinear trajectories. The comparative analysis made it possible to give recommendations on movement along the ellipse and lemniscate, which are characterized by smaller position errors and deviations in the rotation angle compared to more complex curves.

Metasurface‐Enabled Cascaded Multispectral Polarization Structures Along the Longitudinal Direction

AbstractGeneration and manipulation of polarization structures have attracted significant interest due to their unusual optical features and extensive applications. Multispectral information can further increase the information capacity of polarization structures. However, generating multiple cascaded multispectral polarization numbers (letters) at multiple planes arranged along light propagation has not been reported. A geometric metasurface is used to experimentally realize eight cascaded multispectral polarization numbers (letters) at predesigned observation planes along the longitudinal direction. The efficacy of this approach is demonstrated by encoding a single polarization number (letter) with two wavelengths and cascading two polarization numbers with orthogonal polarization rotation angles. Different two‐color polarization numbers (letters) are generated by controlling the incident wavelength, while their polarization distributions are modulated by controlling the incident linear polarization. This approach integrates two‐dimentional (2D) polarization generation, multiple colors, longitudinal control, and cascading design, providing extra degrees of freedom for customized polarization design and enabling small‐volume polarization systems for color display, image steganography, and optical encryption.

Optimization of tensile strength of AlSi10Mg material in the powder bed fusion process using the Taguchi method

This study examined scan speed, hatch distance, and scan rotation angle parameters to determine the effects of the powder bed fusion process on the tensile strength of AlSi10Mg material. The Taguchi L9 experimental design was applied to evaluate the effects of the parameters systematically. The experimental results revealed the importance of the parameters affecting the tensile strength of the AlSi10Mg material. While the scan speed was determined to be the parameter that most affected the tensile strength with a contribution rate of 81.4%, the scan rotation angle and hatch distance were effective at 7.8% and 6.1%, respectively. In the optimization performed using signal/noise analysis, 1200 mm/s scan speed, 80 μm hatch distance, and 17° scan rotation angle were found to be the most suitable parameters to ensure the highest tensile strength. The tensile strength obtained in the verification test was measured at 598 MPa. The findings increase the application potential of SLM technology with AlSi10Mg material and provide valuable information for process optimization. The results can significantly contribute to strategies to increase tensile strength and improve material performance in industrial production processes.

Shape-controlled Bose–Einstein condensation

Abstract Size-invariant shape transformation is a geometric technique that allows for a clear separation between quantum size and shape effects by modifying the shape of the confinement domain without altering its size. The impact of shape on the behavior of confined systems is significantly different from that of size, making it an emerging area of research. The recent realization of flat-bottomed optical box traps has further contributed to the study of quantum gases in complex confinement geometries. Here, we propose shape-induced Bose–Einstein condensation at a fixed size, temperature, and density. We investigate the impact of pure quantum shape effects on a non-interacting Bose gas confined within nested square domains, where the shape parameter is defined and controlled by the rotation angle between the inner and outer squares. Our findings reveal that specific heat exhibits an additional low-temperature peak at certain shapes. This work opens new avenues for controlling quantum systems through geometric manipulation and provides insights into the thermodynamic properties of Bose gases under shape-induced quantum effects.

Faraday rotation in a cavity integrated with layered van der collinear antiferromagnetic material

Abstract Two dimensional layered van der Waals (vdW) ferromagnetic (FM) and anti FM materials enable the alternative candidates for establishing the next-generation magnetooptical (MO) devices. However, the explorations of the MO effects are primarily focused on the layered FM materials and their nanostructures. How the MO responses behave in the structures with vdW layered anti FM materials remain largely unknown. Here, we identify that a layered collinear antiferromagnet supports the nontrivial MO Faraday rotation (FR) angle in the presence of the electric field instead of magnetic field due to its lifted spin degeneracy and asymmetric band structure at different valleys, whose value is comparable with those of vdW layered ferromagnets and closely correlates with the size of the electric field. Specifically, the FR angle of the layered collinear antiferromagnet can be substantially enhanced via integrating it into a cavity structure, which promises the chance of improving their MO performance. Our result highlights the fundamental opportunities of utilizing the collinear antiferromagnets for various MO applications ranging from magnetometry to high density holographic data storage.

Numerical Study of Thermal and Resistance Characteristics in the Vortex-Enhanced Tube

Heat transfer enhancement is always pursued in the industry to achieve high-performance and low-energy-consumption heat exchange devices and systems. For decades, various types of heat transfer-enhancing tubes with differing geometries and wall configurations have been developed. In this paper, the heat transfer and pressure drop characteristics of air inside an innovative heat transfer tube with regular wall dimples, namely a vortex-enhanced tube, which has a great application prospect in the gas–gas heat exchanger, are numerically studied with an experimentally validated model. The effects of the depth, axial pitch, and radial rotation angle of the dimple in the tube wall on the convective heat transfer coefficient and friction drag coefficient are comprehensively analyzed. Based on the Performance Evaluation Criteria (PEC) of the tubes, the optimal parameters of the vortex-enhanced tube are obtained. When Re ranges from 10,000 to 40,000, the comprehensive evaluation factor of the vortex-enhanced tube is 1.29 times higher than the smooth tube. Dimple pacing, dimple depth, and dimple helical angle of the optimal tube type are 8 mm, 6 mm, and 83°, respectively.

Study of Localization-Delocalization Transition of Light in Photonic Moiré Lattices Fabricated with Saturable Nonlinear Materials

Recently, Moiré lattices have received much attention from physicists and materials scientists. These structures have opened the door to the exploration of numerous physical phenomena such as superconductivity, the commensurate-incommensurate transition, the appearance of quasicrystals at special rotation angles, or the two-dimensional localization-delocalization transition of light in linear systems. In this study, we propose photonic Moiré lattices induced by saturable nonlinear materials. After performing numerical simulations, it is observed that there exists a transition between delocalized and localized formation of laser beams under different geometrical conditions, commensurate and incommensurate lattices. The results suggest that Moiré lattices with their compactness and tunability would be utilized to control the light patterns in integrated optical devices.

Electron beam characterization via quantum coherent optical magnetometry

We present a quantum optics-based detection method for determining the position and current of an electron beam. As electrons pass through a dilute vapor of rubidium atoms, their magnetic field perturbs the atomic spin's quantum state and causes polarization rotation of a laser resonant with an optical transition of the atoms. By measuring the polarization rotation angle across the laser beam, we recreate a 2D projection of the magnetic field and use it to determine the e-beam position, size, and total current. We tested this method for an e-beam with currents ranging from 30 to 110 μA. Our approach is insensitive to electron kinetic energy, and we confirmed that experimentally between 10 and 20 keV. This technique offers a unique platform for noninvasive characterization of charged particle beams used in accelerators for particle and nuclear physics research.

Parameterized ZNCC image correlation for rotary-angle measurement

Abstract High-accuracy rotary-angle measurement is critical for precise positioning and control of robots, machine arms, and machine tools in industry. Image-based measurement is a very promising technology for angle positioning owing to its simple system, low cost, and good robustness to environments. Image correlation, such as the zero-mean normalized cross correlation (ZNCC) method, can obtain high accuracy image-positioning results, but their efficiency is too low to directly use in industries. This paper proposes to measure the absolute rotary angle using a parameterized ZNCC (PZNCC) image correlation method. The PZNCC expresses the ZNCC coefficient by the image shift parameters explicitly, so that the precise-match point corresponding to the global ZNCC maximum can be efficiently obtained and no image-resampling process is required. As a result, PZNCC is approximately 5 times faster than the classic inverse compositional Gauss–Newton (IC-GN) algorithm. Experiments show that rotary angle measurement based on PZNCC can obtain absolute angle positions with an accuracy of 1.16 arcsec (RMSE).&amp;#xD;

Low-frequency vibration monitoring system measuring the fringe shift by using linear Fresnel zone plates for shiny surfaces

This paper presents a vibration monitoring system that measures the fringe shift from the Fresnel diffraction pattern for noncontact measurement of translational and angular vibrations. Conventional vibration systems have some major limitations in practical applications. For example, a laser Doppler vibrometer (LDV) fails to accurately measure large-amplitude vibrations of a mirrored object undergoing dynamic tilts or rotations. Additionally, achieving the accuracy required for micro/nanomeasurement in precision machines when measuring low-frequency vibrations (LFV) remains a significant challenge. In this study, the vibration measurement system utilizes a linear Fresnel zone plate with parallel strip lines to create the diffraction pattern. Surface vibrations cause shifts in these lines, and the resulting fringe pattern on the vibrating surface carries information about the local vibrational amplitude and frequency. To achieve this, the linear vibration and displacement of the object are accurately verified using a linear motion platform and a rotation stage, with accuracies of approximately 20 nm and 0.002°, respectively. Rotational vibration measurements utilize tracking beam deflection through the image fringe shift measurement method, while out-of-plane displacement is determined both from this method and from changes in the period density of diffraction patterns, which depend on the position of the patterns and the local spatial frequency. A CCD camera captures sequences of images of the deflected fringes due to vibrating object. The system can detect linear vibrations with frequencies above 251.91 µHz and has a displacement uncertainty of approximately 5.8 µm, achieving an angular resolution of 37.67 µrad. Compared to conventional LDV vibrometers and eddy current sensors, the proposed method offers an effective and accurate technique for measuring LFVs of shiny surfaces. Furthermore, it provides a significantly extended measurement range for both translation and rotational angles of objects in engineering applications.