Rotation Of Plane Research Articles

Total knee arthroplasty, different alignment and balance methods- A review

The two most frequent techniques used to implant a total knee replacement (TKR) are measured resection and gap balancing. Both methods have been around for a while and are currently in widespread usage, and both have shown to be effective in the real world. Plus, new technologies have evolved in the recent past to help surgeons achieve soft tissue balance and limb alignment.Proper alignment of a knee replacement is crucial to its effective functioning. It has to be in the right axial and rotational planes for this to work. Patellofemoral instability and early wear can be caused by improper alignment, as can loosening of the prosthesis. Altering the prosthesis's orientation might potentially affect the tension of the surrounding soft tissues. We have extensively reviewed 50 studies (Level 1- Level 4) published in many prestigious journals by searching through platforms like PUBMED, MEDLINE and EMBASE databases. In this research, we have attempted to document the relationship between alignment and the equilibrium of soft tissues and to summarize the present state of our understanding of this connection.

Reversible chiral structure transformation of ultra-thin gold nanowire under tensile strain conditions

Behaviors of ultrathin metallic nanowires under strain conditions have attracted plenty of interest due to their unique properties and structures. Here, for the first time, we provide direct atomic-scale observations of the reversible chiral structure transformation of the gold nanowire under tensile strain conditions in transmission electron microscopy. The formation and disappearance of a 〈111〉 projection in the 〈110〉 projected nanowire were observed during the structural transformation. We reveal that the chiral structure transformation is induced by the nanowire twisting behavior, which is achieved via atomic plane rotation and nanowire bending. Our results provide direct evidence for an expressive and deterministic reversible transformation from a symmetrical face-centered-cubic structure to the chiral structure of gold nanowires, which enables an atomic-scale understanding of the behavior of ultra-thin nanostructure and provides guidance in the design of nano-devices.

Assessment of Numerical Captive Model Tests for Underwater Vehicles: The DARPA SUB-OFF Test Case

During the early design stage of an underwater vehicle, the correct assessment of its manoeuvrability is a crucial task. Conducting experimental tests still has high costs, especially when dealing with small vehicles characterized by low available budget. In the current investigation, virtual towing tank tests are simulated using the open-source OpenFOAM library in order to assess the reliability of CFD methods for the prediction of hydrodynamic forces and moments. A well-known case study, the Defence Advanced Research Projects Agency (DARPA) SUB-OFF model, is used, and the outcomes are compared to the experimental results available in the literature. Five different configurations are investigated for pure drift tests, rudder tests and pure rotation in both vertical and horizontal plane. The results show an overall good agreement with the experimental data with a quite low demanding mesh arrangement of 3M cells, a favourable balance between accuracy and computational time. In more detail, the expected error in the most significant forces during manoeuvres is less than 2% for the fully appended configuration (the submarine real operative condition), whereas the accuracy is moderately reduced for the barehull configuration (a case not representative of a real hull) with an expected error of 15%. A possible reason for the differences observed could be attributed to the description of the two streamwise vortices generated when manoeuvring. Apart from the lateral force and yaw moment, the results of the longitudinal force are also presented, having a greater disparity when compared to the experimental data. Nevertheless, the longitudinal force has no important role for the purpose of making stability and control predictions. The study contributes to the validation and consolidation of CFD methods, offering insights into their accuracy and limitations for practical applications in underwater vehicles.

Vertical changes in the hard tissues after space closure by miniscrew sliding mechanics: a three-dimensional modality analysis

ObjectivesThis study aimed to investigate vertical changes in the maxillary central incisor and the maxillary first molar, along with alterations in the mandibular plane angle during space closure using miniscrew sliding mechanics.MethodsTwenty adult patients treated at Peking University Hospital of Stomatology between 2008 and 2013 were included. Digital dental models and craniofacial cone-beam computed tomography (CBCT) scans were obtained at the start of treatment (T0) and immediately after space closure (T1). Stable miniscrews were used for superimposing maxillary digital dental models (T0 and T1), and vertical changes in the maxillary first molar and the maxillary central incisor were measured. Three-dimensional changes in the mandibular plane were assessed through CBCT superimposition.ResultsThe maxillary central incisor exhibited an average extrusion of 2.56 ± 0.18 mm, while the maxillary first molar showed an average intrusion of 1.25 ± 1.11 mm with a distal movement of 0.97 ± 0.99 mm. Additionally, the mandibular plane angle decreased by an average of 0.83 ± 1.65°. All three indices exhibited statistically significant differences.ConclusionDuring space closure using the miniscrew sliding technique, significant changes occurred in both the sagittal and vertical dimensions of the upper dentition. This included extrusion of the maxillary central incisors, intrusion of the maxillary first molars, and a slight counterclockwise rotation of the mandibular plane.

A generalized visibility graph algorithm for analyzing biological time series having rotation in polar plane

Time series analysis is exploited when temporal measurements about a phenomenon exist. Visibility graphs are a method for representing and analyzing time series. One of the challenges biological time series introduce is rotation in polar plane. Rotation in polar plane is a change in the angle of the time series in polar plane. Rotation in the polar plane exists in any time series that has positive and negative observations together. In this research, a visibility graph algorithm is proposed which could efficiently handle biological time series which have rotation in polar plane. In the proposed algorithm, two observation in the time series are visible to each other in the graph, if the line connecting the points doesn't cross any other point placed between them. The proposed visibility graph algorithm has been evaluated with synthetic and real world time series. The generated visibility graphs are used to evaluate the proposed visibility graph algorithm with different metrics such as pearson autocorrelation and classification accuracy. The synthetic time series are generated by a bipolar feedback process. In one of the synthetic bios series with g = 10, the pearson autocorrelation of the graph is 0.9815 whereas the baseline is 0.9211. In the main experiment with real world time series, the proposed visibility graph algorithm is compared with the state of the art algorithm. The ANOVA test is performed on the results of 60 experiments. The p-value is smaller than 0.05, which states GVG has improved CLPVG significantly.

Comparative experimental study on shaking table test of small radius curved bridge considering different connection types between pier and beam

During the Great Wenchuan Ms 8.0 earthquake, many small-radius curved bridges suffered varying degrees of damage, including Baihua Bridge, Huilan Overpass, and Xiaohuangou Bridge. To understand the damage mechanism, shaking table tests were conducted on two scaled bridge models with different middle pier connection types. In one model, the middle pier and beam were cast monolithically together (CM bridge), while the other had a fixed support installed at the pier-beam connection (FS bridge). Both bridges were subjected to two earthquake ground motions. Visually, damage differed considerably between the bridges. The CM bridge exhibited many horizontal and circumferential cracks at the top and bottom. Meanwhile, the FS bridge concrete was crushed at the top of the middle pier, which must be paid attention to. Amplification factors, maximum drift ratios, residual drift, planar rotation angles, and bearing slip were analyzed for both bridges. For both structures, amplification factors in the X and Y directions decreased with stronger ground motions, while those in the Z direction showed an opposite trend; meanwhile, maximum drift ratios, residual drift, rotation angles, and bearing slip all increased with stronger motions. The acceleration amplification factors of the CM bridge increased with greater ground motion, rising rapidly. The CM bridge saw a maximum drift ratio of 7.07 versus 3.16 for the FS bridge. The trend for the CM bridge was a gradual increase, while the FS bridge had a sudden increase after the maximum drift ratio reached 1.61%. The CM bridge planar rotation angle rose gradually to 0.23°, while the FS bridge angle increased much faster, reaching 0.54° or 2.35 times that of the CM bridge. The FS bridge concrete splitting failure demonstrated vulnerability to seismic events exceeding the design level and the structural measures in this region should be enhanced in the design.

The Relativistic Rotation Transformation and the Observer Manifold

We show that relativistic rotation transformations represent transfer maps between the laboratory system and a local observer on an observer manifold, rather than an event manifold, in the spirit of C-equivalence. Rotation is, therefore, not a parameterised motion on a background space or spacetime, but is determined by a particular sequence of tetrads related by specific special Lorentz transformations or boosts. Because such Lorentz boosts do not form a group, these tetrads represent distinct observers that cannot put together their local descriptions into a manifold in the usual sense. The choice of observer manifold depends on the dynamical situation under consideration, and is not solely determined by the kinematics. Three examples are given: Franklin’s rotation transformation for uniform plane rotation, the Thomas precession of a vector attached to an electron, and the motion of a charged particle in an electromagnetic field. In each case, at each point of its trajectory, there is a distinguished tetrad and a special Lorentz transformation that maps Minkowski space to the spacetime of the local observer on the curve.

Effects of number of blades on propeller noise

This paper presents the effect of the number of blades on the aeroacoustic characteristics and aerodynamic performance of propellers utilized in urban air mobility vehicles through an extensive experimental study. A detailed parametric study is conducted for two, three, and five-bladed propellers. Investigations are carried out under static thrust conditions and incoming axial flow velocities for various rotational speeds. The spectra and directivity of the far-field noise are studied in detail for broadband and tonal components. Results show that two-bladed propellers produce higher tonal noise levels than other blade numbers for the same tip speed, while five-bladed propellers produce the highest broadband noise levels. The highest level of noise radiation is noted in the upstream and downstream directions for broadband noise, whereas tonal noise is radiated mainly in the plane of rotation. Results also indicate that high-frequency broadband humps are observed for higher advance ratios, likely caused by the formation of laminar separation bubbles, and that amplitude increases with blade numbers. The results of this study provide valuable insight for further investigations of propeller noise and aerodynamic performance.

Polarization control and enhanced magnetic field sensitivity utilizing surface plasmon polaritons-assisted dual-V-type four-level system

We propose a kind of surface plasmon polaritons (SPPs)-assisted dual-V-type four-level composite system used for high-sensitivity weak magnetic field measurement. The SPPs are excited by a D-shaped photonic crystal fiber (PCF) deposited with gold nanowires, and are interacted with the above quantum emitter from the rubidium atomic vapor. In the presence of the external magnetic field, Faraday rotation symmetry is broken due to Zeeman effect, resulting in the polarization plane rotation when a linearly polarized probe field goes through the above quantum emitter. With the help of the coupled field and SPPs, Faraday magneto-optical rotation (MOR) are effectively regulated. The Rabi frequency of the coupled field (Ω c ), quantum interference degree (q), and phase difference (φ) between the applied fields show strong dependence on the MOR angle and magnetic field measurement sensitivity. The simulated results reveal that the maximum MOR angle and magnetic field sensitivity both damp with Ω c expanding and q reducing. The maximum dichroism-independent MOR angle of 89.97° is realized for φ = 0° (180°), and the magnetic field sensitivity of 10.88°/Oe is obtained in the sweeping range of −8.88–8.88 Oe for q = 0.99, being 2.66°/Oe higher than that in the absence of SPPs (q = 0). Most importantly, the output probe field with different polarization forms can be realized by adjusting the φ value. Hence, the proposed device exhibits the potential in the fields of weak magnetic field measurement and polarization control.

Electromagnetic curves and Rytov’s law in the optical fiber with Maxwellian evolution via alternative moving frame

In this study, we research the behavior of a linearly-polarized light wave in optical fiber and the rotation of the polarization plane through the alternative moving frame { N,C,W } in Minkowski 3-space. Then Berry’s phase equations are discussed for electromagnetic curves in the { C } and { W } directions along an optic fiber via alternative moving frame in Minkowski 3-space. Moreover, electromagnetic curve’s { C } and { W } Rytov parallel transportation laws are defined. Finally, we examine the electromagnetic curve’s Maxwellian evolution by Maxwell’s equation.

Matrix elements of SO(3) in sl3 representations as bispectral multivariate functions

We compute the matrix elements of SO(3) in any finite-dimensional irreducible representation of sl3. They are expressed in terms of a double sum of products of Krawtchouk and Racah polynomials which generalize the Griffiths–Krawtchouk polynomials. Their recurrence and difference relations are obtained as byproducts of our construction. The proof is based on the decomposition of a general three-dimensional rotation in terms of elementary planar rotations and a transition between two embeddings of sl2 in sl3. The former is related to monovariate Krawtchouk polynomials and the latter, to monovariate Racah polynomials. The appearance of Racah polynomials in this context is algebraically explained by showing that the two sl2 Casimir elements related to the two embeddings of sl2 in sl3 obey the Racah algebra relations. We also show that these two elements generate the centralizer in U(sl3) of the Cartan subalgebra and its complete algebraic description is given.

Dynamic strain fields of the mouse brain during rotation.

Mouse models are used to better understand brain injury mechanisms in humans, yet there is a limited understanding of biomechanical relevance, beginning with how the murine brain deforms when the head undergoes rapid rotation from blunt impact. This problem makes it difficult to translate some aspects of diffuse axonal injury from mouse to human. To address this gap, we present the two-dimensional strain field of the mouse brain undergoing dynamic rotation in the sagittal plane. Using a high-speed camera with digital image correlation measurements of the exposed mid-sagittal brain surface, we found that pure rotations (no direct impact to the skull) of 100-200rad/s are capable of producing complex strain fields that evolve over time with respect to rotational acceleration and deceleration. At the highest rotational velocity tested, the largest tensile strains (≥ 21% elongation) in selected regions of the mouse brain approach strain thresholds previously associated with axonal injury in prior work. These findings provide a benchmark to validate the mechanical response in biomechanical computational models predicting diffuse axonal injury, but much work remains in correlating tissue deformation patterns from computational models with underlying neuropathology.

Species dependence of the impurity injection induced poloidal flow and magnetic island rotation in a tokamak

Recent experiments have demonstrated the species dependence of the impurity poloidal drift direction along with the magnetic island rotation in the poloidal plane. Our resistive MHD simulations have reproduced such a dependence of the impurity poloidal flow, which is found mainly determined by a local plasmoid formation due to the impurity injection. The synchronized magnetic island rotation is dominantly driven by the electromagnetic torque produced by the impurity radiation primarily through the modification to the axisymmetric components of current density.

Biomechanical comparison of open Bankart repair vs. conjoint tendon transfer in a 10% anterior glenoid bone loss shoulder instability model

The treatment of shoulder instability in patients with subcritical glenoid bone loss poses a difficult problem for surgeons as new evidence supports a higher failure rate when a standard arthroscopic Bankart repair is used. The purpose of this study was to compare a conjoint tendon transfer (soft-tissue Bristow) to an open Bankart repair in a cadaveric instability model of 10% glenoid bone loss. Eight cadaveric shoulders were tested using a custom testing system that allows for a 6-degree-of-freedom positioning of the glenohumeral joint. The rotator cuff muscles were loaded to simulate physiologic muscle conditions. Four conditions were tested: (1) intact, (2) Bankart lesion with 10% bone loss, (3) conjoint tendon transfer, and (4) open Bankart repair. Range of motion, glenohumeral kinematics, and anterior-inferior translation at 60° of external rotation with 20 N, 30 N, and 40 N were measured in the scapular and coronal planes. Glenohumeral joint translational stiffness was calculated as the linear fit of the translational force-displacement curve. Force to anterior-inferior dislocation was also measured in the coronal plane. Repeated measures analysis of variance with a Bonferroni correction was used for statistical analysis. A Bankart lesion with 10% bone loss increased the range of motion in both the scapular (P=.001) and coronal planes (P=.001). The conjoint tendon transfer had a minimal effect on the range of motion (vs. intact P=.019, .002), but the Bankart repair decreased the range of motion to intact (P=.9, .4). There was a significant decrease in glenohumeral joint translational stiffness for the Bankart lesion compared with intact in the coronal plane (P=.021). The conjoint tendon transfer significantly increased stiffness in the scapular plane (P=.034), and the Bankart repair increased stiffness in the coronal plane (P=.037) compared with the Bankart lesion. The conjoint tendon transfer shifted the humeral head posteriorly at 60° and 90° of external rotation in the scapular plane. The Bankart repair shifted the head posteriorly in maximum external rotation in the coronal plane. There was no significant difference in force to dislocation between the Bankart repair (75.8±6.6 N) and the conjoint tendon transfer (66.5±4.4 N) (P=.151). In the setting of subcritical bone loss, both the open Bankart repair and conjoint tendon transfer are biomechanically viable options for the treatment of anterior shoulder instability; further studies are needed to extrapolate these data to the clinical setting.

Surgical navigation for guidewire placement from intraoperative fluoroscopy in orthopaedic surgery.

Objective. Surgical guidewires are commonly used in placing fixation implants to stabilize fractures. Accurate positioning of these instruments is challenged by difficulties in 3D reckoning from 2D fluoroscopy. This work aims to enhance the accuracy and reduce exposure times by providing 3D navigation for guidewire placement from as little as two fluoroscopic images.Approach. Our approach combines machine learning-based segmentation with the geometric model of the imager to determine the 3D poses of guidewires. Instrument tips are encoded as individual keypoints, and the segmentation masks are processed to estimate the trajectory. Correspondence between detections in multiple views is established using the pre-calibrated system geometry, and the corresponding features are backprojected to obtain the 3D pose. Guidewire 3D directions were computed using both an analytical and an optimization-based method. The complete approach was evaluated in cadaveric specimens with respect to potential confounding effects from the imaging geometry and radiographic scene clutter due to other instruments.Main results. The detection network identified the guidewire tips within 2.2 mm and guidewire directions within 1.1°, in 2D detector coordinates. Feature correspondence rejected false detections, particularly in images with other instruments, to achieve 83% precision and 90% recall. Estimating the 3D direction via numerical optimization showed added robustness to guidewires aligned with the gantry rotation plane. Guidewire tips and directions were localized in 3D world coordinates with a median accuracy of 1.8 mm and 2.7°, respectively.Significance. The paper reports a new method for automatic 2D detection and 3D localization of guidewires from pairs of fluoroscopic images. Localized guidewires can be virtually overlaid on the patient's pre-operative 3D scan during the intervention. Accurate pose determination for multiple guidewires from two images offers to reduce radiation dose by minimizing the need for repeated imaging and provides quantitative feedback prior to implant placement.

Incommensurate magnetic structure of CrAs at low temperatures and high pressures.

The magnetic structure of chromium arsenide CrAs is studied with neutron powder diffraction at ambient pressure in the temperature range 1.5-300 K as well as with neutron single-crystal diffraction at 2 K and 0.12 GPa. The material undergoes an anti-isostructural phase transition at TN = 267 K and atmospheric conditions, in which both orthorhombic phases have the same space-group symmetry (Pnma, Z = 4) but different distortions of the parent hexagonal structure of the NiAs type (P63/mmc, Z = 2). The magnetic structure below TN is incommensurate with the propagation vector k = (0, 0, kc). At ambient pressure, the component kc decreases from kc = 0.3807 (7) at 260 K to kc = 0.3531 (6) at 50 K. Below this temperature, it is basically constant. With increasing pressure at 2 K, kc is also constant within standard uncertainties [kc = 0.353 (2)]. For the analysis of the magnetic structure, a group-theoretical approach based on the space group of the nuclear structure and its subgroups is used. To avoid falling into false minima in the refinements, a random search for magnetic moments in the models is implemented. In the literature, the magnetic structure has been determined on the basis of powder diffraction data as a double helix propagating along the c axis. Although this double-helical model leads to satisfactory agreement factors for our powder data, it does not reproduce the intensities of the magnetic satellite reflections measured on single-crystal data in a satisfactory way and can therefore be discarded. Instead, several other models are found that lead to better agreement. Each of them is spiral-like with directional components in all three directions and with no spin-density wave character that would cause a non-constant magnetic moment. In all these models, the ordering of the spins is neither a pure helix nor a pure cycloid. Instead, the unit vectors of the spin rotation planes make an angle α, 0° < α < 90°, with respect to the c* direction. The model in superspace group P21.1'(α0γ)0s yields the best agreement factors in the refinements of the neutron single-crystal and powder diffraction data. This model is unique as it is the only one in which all the magnetic moments rotate with the same chirality.

Ankle and subtalar joint axes of rotation and center of rotation during walking and running in healthy individuals measured using dynamic biplane radiography

The goal of this study was to determine how foot type and activity level affect ankle and hindfoot motion. Dynamic biplane radiography and a validated volumetric registration process was used to measure ankle and hindfoot motion of 20 healthy adults during walking and running. The helical axes of motion (HAM) during stance were calculated at the tibiotalar and subtalar joints. The intersection of each HAM and the rotation plane of interest defined the tibiotalar and subtalar centers of rotation (COR). Correlations between foot type and hindfoot kinematics were calculated using Pearson’s correlations. The effect of activity, phase of gait, and dominant vs. non-dominant limb on HAM and COR were evaluated using linear mixed effects models. Activity and phase of gait influenced the superior location of the tibiotalar (p < 0.041) and subtalar (p < 0.044) CORs. Activity and gait phase affected tibiotalar (p < 0.049) and subtalar (p < 0.044) HAM direction during gait. Both HAM orientation and COR location changed with activity and phase of gait. These ankle and hindfoot kinematics have implications for total ankle replacement design and musculoskeletal models that estimate force and moment generating capabilities of muscles.

On some rational piecewise linear rotations

We study the dynamics of the piecewise planar rotations F λ ( z ) = λ ( z − H ( z ) ) , with z ∈ C , H ( z ) = 1 if Im ( z ) ≥ 0 , H ( z ) = − 1 if Im ( z ) < 0 , and λ = e iα ∈ C , being α a rational multiple of π. Our main results establish the dynamics in the so called regular set, which is the complementary of the closure of the set formed by the preimages of the discontinuity line. We prove that any connected component of this set is open, bounded and periodic under the action of F λ , with a period ℓ, that depends on the connected component. Furthermore, F λ ℓ restricted to each component acts as a rotation with a period which also depends on the connected component. As a consequence, any point in the regular set is periodic. Among other results, we also prove that for any connected component of the regular set, its boundary is a convex polygon with certain maximum number of sides.

Effects of shoe collar types on ankle and knee biomechanics characteristics when performing the side-step cutting task

ABSTRACT This study aimed to examine the effect of football shoes with different collar types on ankle and knee kinematic and kinetics features during 45° and 135° side-step cutting tasks. Fifteen healthy college football players volunteered for the study. Each participant was instructed to perform side-step cutting tasks with high, low, and no collar football shoes. The kinematic and ground reaction force data were measured using a Vicon motion capture system and a Kistler force plate, respectively. Two-way MANOVAs with repeated measures were used to examine the effect of shoe collar type and task conditions. There were no interaction effects. The high collar football shoe showed decreased ankle range of motion in the sagittal plane (p = 0.010) and peak ankle external rotation moment (p = 0.009) compared to the no collar football shoe. The high (p = 0.025) and low (p = 0.029) collar football shoes presented greater peak ankle external rotation angles than the no collar football shoe. These results imply that football shoes with high collars made of high intensity knitted fabric could be used to restrict ankle joint movement, with potential implications for decreasing the risk of ankle sprain injuries in football players.

Developing an Ovine Model of Impact Traumatic Brain Injury

&lt;div&gt;Traumatic brain injury is a leading cause of global death and disability. Clinically relevant large animal models are a vital tool for understanding the biomechanics of injury, providing validation data for computation models, and advancing clinical translation of laboratory findings. It is well-established that large angular accelerations of the head can cause TBI, but the effect of head impact on the extent and severity of brain pathology remains unclear. Clinically, most TBIs occur with direct head impact, as opposed to inertial injuries where the head is accelerated without direct impact. There are currently no active large animal models of impact TBI. Sheep may provide a valuable model for studying TBI biomechanics, with relatively large brains that are similar in structure to that of humans. The aim of this project is to develop an ovine model of impact TBI to study the relationships between impact mechanics and brain pathology. An elastic energy impact injury device has been developed to apply scalable head impacts to rapidly rotate the head without causing hard tissue damage. A motion constraint device has been developed to limit the head motion to a single plane of rotation. The apparatus has been tested using deceased animals to assess the controllability of impact velocities, the repeatability of head kinematics, and the dynamic response of the head to impact. Impact velocities are effectively controlled by modulating the elastic energy stored in the impact piston. The resulting head kinematics are somewhat variable, and are influenced by impact location, time-dependent postmortem tissue changes, and specimen head and neck physiology. Model development will continue, and in vivo testing will be conducted to assess the brain pathology following impacts of varying severity.&lt;/div&gt;