Rotation Changes Research Articles

Rotational dynamics of a neutrally buoyant prolate spheroid in viscoelastic shear flows at finite Reynolds numbers

Non-spherical particles exhibit peculiar behaviour in non-Newtonian flows. In this paper, we numerically investigate the dynamics of a neutrally buoyant prolate spheroid immersed in viscoelastic shear flows at finite Reynolds numbers by means of the immersed boundary method. Our results show that the period of particle rotation changes monotonically with the solvent viscosity ratio but non-monotonically with the mobility factor. Furthermore, we find five rotation modes of the spheroid under the effects of fluid inertia and fluid rheology in the present flow configuration. With weak fluid inertia, the particle rotation rate is remarkably reduced by fluid elasticity, which also induces asymmetric rotational behaviour. While the particle tends to tumble in the shear plane with weak fluid elasticity and moderate fluid inertia. However, as the fluid elasticity increases, the particle rotates with a newly observed mode, named the asymmetric-kayaking mode, which is classified by two additional critical elastic numbers that differ from the earlier studies on Stokesian viscoelastic shear flows. The present findings imply the importance of fluid inertia and fluid elasticity on the particle dynamics and could be potentially used to control the particle orientations in viscoelastic fluid flows.

Promising results of an non-invasive measurement of knee implant loosening using a loading device, CT-scans and 3D image analysis

BackgroundAfter total knee arthroplasty up to 13% requires revision surgery to address loosening. No current diagnostic modalities have a sensitivity or specificity higher than 70–80% to detect loosening, leading to 20–30% of patients undergoing unnecessary, risky and expensive revision surgery. A reliable imaging modality is required to diagnose loosening. This study presents a new and non-invasive method and evaluates its reproducibility and reliability in a cadaveric study. MethodsTen cadaveric specimens were implanted with a loosely fitted tibial components and CT scanned under load towards valgus and varus using a loading device. Advanced three-dimensional imaging software was used to quantify displacement. Subsequently, the implants were fixed to the bone and scanned to determine the differences between the fixed and the loose state. Reproducibility errors were quantified using a frozen specimen in which displacement was absent. FindingsReproducibility errors, expressed as mean target registration error, screw-axis rotation and maximum total point motion were 0.073 mm (SD 0.033), 0.129 degrees (SD 0.039) and 0.116 mm (SD 0.031), respectively. In the loose condition, all displacements and rotation changes were larger than the reported reproducibility errors. Comparing the mean target registration error, screw axis rotation and maximum total point motion in the loose condition to the fixed condition resulted in mean differences of 0.463 mm (SD 0.279; p = 0.001), 1.769 degrees (SD 0.868; p < 0.001) and 1.339 mm (SD 0.712; p < 0.001), respectively. InterpretationThe results of this cadaveric study show that this non-invasive method is reproducible and reliable for detection of displacement differences between fixed and loose tibial components.

Leakage Flow Impact on Shrouded Stator Cavity Flow Topology and Associated High-Speed Axial Compressor Stage Performance

AbstractThis paper presents the investigation of realistic cavity leakage flow for the von Karman Institute for Fluid Dynamics H25 axial compressor stage, equipped with a shroud cavity of average Reynolds number Rer = 2.2 * 106 and average aspect ratio G = 0.06. On top of overall performance measurements, time averaged data from unprecedented experimental dataset are used to characterize the stator hub shroud cavity flow field and its interaction with the power stream. The sensitivity of the stage performance and stability as well as the cavity flow topology is evaluated against injection conditions, compressor throttling, and compressor speed. Parametric steady RANS simulations of the stage under injection are used to support the findings and state on the relevance of such approach in the preliminary design phase of axial compressor components. As an example, a stage efficiency reduction of 0.97% for a leakage fraction of 0.56% at design point is retrieved. This performance drop is attributed to the effect of cavity flow on: the blockage ratio, the boundary layer skewness, and total temperature increase at stator row inlet. It is also presented that there is a mutual interaction between the cavity geometry and the cavity flow field organization. The injection homogenizes the cavity flow field and the associated pressure gradient. The various operating conditions presented also demonstrate that the cavity flow studied is, on average (i.e., time), sensitive to changes in compressor rotation speed and changes in stage loading.

Septal extension graft use in the treatment of alar collapse.

In our study, we showed that the septal extension graft (SEG) technique, which we applied for nasal projection in rhinoplasty surgery, increases the tension of the lateral cartilage (LC) and alar structures. We also demonstrated that nasal congestion could be treated by applying this technique in patients with nasal obstruction due to bilateral dynamic alar collapse. This study was conducted retrospectively on 23 patients with nasal obstruction due to alar collapse. Bilateral dynamic nasal collapse and (+) Cottle test was present in all patients. Nasal lateral wall tissue was also found flaccid on nasal palpation and collapsed to the extent of obstruction on deep inspiration. Standard septal extension graft (SEG) and tongue-in-groove techniques were applied to all patients. Septal cartilage was used for SEG in all patients. No complaints of nasal obstruction on deep inspiration were noted by the patients at six months postoperative follow-up, and Cottle tests were negative. The patients' mean respiratory score was 152 postoperatively, compared to 66.5 preoperatively. This difference was statistically significant using the Wilcoxon signed ranks test (p<0.001). In evaluating postoperative cosmetic appearance due to nasal tip projection (NTP) and cephalic rotation changes, 16 men and four women reported that it was better, while two men felt that there was no change. One woman reported that her cosmetic appearance was worse than before; a revision surgery was performed for her at seven months postoperatively. This method is effective for patients with bilateral nasal collapse and thick-short columella. With the applied surgery, the caudal edge of the LC diverges from the septum, alar region tension and resistance increase, the columella increases in length, nasal projection increases, and the vestibule cross-sectional area is enlarged. In this way, a significant increase in nasal vestibular volume was obtained.

Tilting installation of wheels rotation planes and changes in operating properties of the vehicle

The purpose of the study is to determine the elastic properties of the tilted wheel and to identify their relationship with the operating properties of the vehicle. A study was made of influence of the wheel tilting installation on the change in its elastic properties at operation. It has been found that normal tire stiffness is reduced by up to 15 % at a maximum tilt angle of 3.50, limited by tire durability conditions. A scheme of the influence of the stiffness types of the tilting wheel on the vehicle operational properties has been developed. Keywords: elastic wheel, tilt of rotation plane, outer wheel tilt, inner wheel tilt, change in elastic properties, operating properties of the vehicle

Rotational stability of plate-haptic toric intraocular lenses in Asian eyes: risk period for intraocular lens rotation and its influencing factors.

To investigate the rotational stability of plate-haptic toric intraocular lenses (IOLs) during 3-month follow-up. Eye and ENT Hospital of Fudan University, Shanghai, China. Prospective observational study. Patients with cataracts implanted with AT TORBI 709M toric IOLs were enrolled and followed at 1 hour, 1 day, 3 days, 1 week, 2 weeks, 1 month, and 3 months postoperatively. A linear mixed model of repeated measures was applied to investigate the time course of absolute IOL rotation change. The 2-week overall IOL rotation was analyzed in the age, sex, axial length (AL), lens thickness (LT), preexisting astigmatism, and white-to-white subgroups. A total of 328 eyes of 258 patients were included. The rotation from the end of surgery to 1 hour and 1 day to 3 days was significantly smaller compared with the rotation from 1 hour to 1 day but more than that at other time intervals in the overall group. 2 weeks postoperatively, the mean uncorrected distance visual acuity and remaining positive cylinder were 0.19 ± 0.22 logMAR and 0.60 ± 0.44 diopters, respectively. Significant between-group differences in 2-week overall rotation were found in the age, AL, and LT subgroups. Maximum rotation occurred within 1 hour to 1 day postoperatively, and the first 3 days postoperatively was a high-risk period for the plate-haptic toric IOL rotation. Surgeons should make the patients aware of this.

Effects of asymmetric trunk muscle fatigue on pelvic inclination and rotation

Although the influence of muscle activity on the pelvic position has been proven, research on the influence of (asymmetric) muscle fatigue on the pelvic position is inconsistent. The purpose of the present study was to assess the effects of asymmetric fatigue of the lateral trunk muscles on the pelvic position based on a pre/post/follow-up design. For the final data analysis, 38 subjects (20 men, 18 women; age 22.63 ± 3.91 years) were asked to perform side bends in sets of 20 repetitions on a Roman chair until complete exhaustion. For pre-, post-, and follow-up test (24 h after treatment), pelvic positions were recorded with a 3D photogrammetric scan. Statistical analysis showed no systematic changes in pelvic inclination and rotation after unilateral exhaustion for the three measuring times. However, highly individual, non-systematic changes in pelvic positions were present, especially between pre- and post-test. The follow-up measurements tend to return to the initial pre-test state. Unilateral fatigue of the lateral flexors of the trunk affects the pelvic position in a non-systematic way.

Plastic hinge rotations of steel braces estimated using improved physical theory models

The cyclic response of a typical steel brace cannot be easily captured due to its asymmetric force-deformation relation due to buckling resulting in substantially strength deterioration. Regardless of experimental and analytical efforts on the behavior of steel braces, current physical theory models overestimate their compression strengths after buckling. This study first reviewed the formulations employed in the current physical theory model and then carried out full scale cyclic tests of W-shaped steel braces to find out and to expose problems of the current physical theory model. The tests show that plastic hinge rotations from the maximum tensile strength to the maximum compressive strength are not maintained, which does not agree with the underlying assumption of the current physical theory model. This paper suggests the improved model that can employ a new finding on the behavior of plastic hinges at buckled steel braces. It was confirmed from the validation that the improved model with a nonlinear assumption can properly capture the changes of hinge rotations during the excursion between the maximum tensile and compressive loads and can be the best candidate for addressing the shortcoming of the existing physical theory model.

A Novel Monogenic Sobel Directional Pattern (MSDP) and Enhanced Bat Algorithm-Based Optimization (BAO) with Pearson Mutation (PM) for Facial Emotion Recognition

In this paper, a novel Monogenic Sobel Directional Pattern (MSDP) using fractional order masks is proposed for extracting features. The MSDP uses fractional-order Sobel masks to identify thin edges along with color and texture-based information thereby increasing performance. Other edge-detection methods can identify only thick edges. There are three modules namely feature extraction, dimension reduction via a novel discriminant analysis method, and classification using a Convolutional Neural Network (CNN). The proposed MSDP is insensitive to the rotation and scaling changes existing in the images. The Bat Algorithm-based Optimization (BAO) is used for the selection of the best parameters of MSDP. The best value is modified by the Pearson Mutation (PM) operator in an effort to aid the algorithm in avoiding local optima and achieving a balance between global and local searches. The proposed work uses CNN for classification and achieves higher classification accuracy for six datasets.

Quasi-periodic large-scale vortex structure in bod bundle lattice with micro ribs

Quasi-periodic large-scale vortex structure (QLVS) is highly accounted for the local flow and heat transfer and turbulent mixing in rod bundles. The vortex structures between rod bundles with different rib heights are analyzed, and the morphology of QLVS is clarified. The mechanism of the QLVS is studied from the perspective of hydrodynamics, and the formation and development process of the QLVS are analyzed in detail. Combined with the criterion of QLVS, the rotation, deformation and velocity changes of small disturbance are analyzed. With the increase of the height of the micro-rib, QLVS is introduced and gradually enhanced. The velocity gradient between different fluid layers is a key factor in the formation and development of QLVS structures. This research can provide theoretical support for the design and optimization of rod bundle lattices.

THE LIGAMENTOUS CONTRIBUTION TO STABILITY AT THE DISTAL RADIOULNAR JOINT

The triangular fibrocartilage complex (TFCC) is a known stabiliser of the distal radioulnar joint (DRUJ). An injury to these structures can result in significant disability including pain, weakness and joint stiffness. The contribution each of its components makes to the stability of the TFCC is not well understood. This study was undertaken to investigate the role of the individual ligaments of the TFCC and their contribution to joint stability.The study was undertaken in two parts. 30 cadaveric forearms were studied in each group. The ligaments of the TFCC were progressively sectioned and the resulting effect on the stability of the DRUJ was measured. A custom jig was created to apply a 20N force through the distal radius, with the ulna fixed.Experiment one measured the effect on DRUJ translation after TFCC sectioning. Experiment two added the measurement of rotational instability.Part one of the study showed that complete sectioning of the TFCC caused a mean increase in translation of 6.09(±3) mm. Sectioning the palmar radioulnar ligament of the TFCC caused the most translation.Part two demonstrated a change in rotation with a mean of 18 (± 6) degrees following sectioning of the TFCC. There was a progressive increase in rotational instability until the palmar radioulnar ligament was also sectioned.Linear translation consistently increased after sectioning all of the TFCC ligaments, confirming its importance for DRUJ stability. Sectioning of the palmar radioulnar ligament most commonly caused the greatest degree of translation. This suggests injury to this ligament would more likely result in a greater degree of translational instability. The increase in rotation also suggests that this type of instability would be symptomatic in a TFCC injury.

Posterior cruciate ligament resection under minimum medial collateral ligament release changes tibial internal rotation, joint center gap, and varus ligament balance on joint distraction force at flexion in total knee arthroplasty

BackgroundThe purpose of this study was to assess the effect of posterior cruciate ligament resection under minimum medial collateral ligament release on the joint center gap, varus ligament balance, and the rotational change of the femur and tibia. MethodsThis study included 75 knees with varus osteoarthritis that underwent total knee arthroplasty. After minimum medial collateral ligament releases and bone resection of the distal femur and proximal tibia, the joint center gap and varus ligament balance were measured before and after posterior cruciate ligament resection using a digital tensor with a joint distraction force of 89, 133, 178 N. The rotational changes under a distraction force of 200 N were captured using a navigation system. FindingsThe joint center gap and varus ligament balance at 90° and 120° of flexion significantly increased after posterior cruciate ligament resection with distraction forces of 89 N (90°: 0.4 mm / 0.9° and 120°: 0.5 mm / 0.8°), 133 N (90°: 0.9 mm / 1.3° and 120°: 0.9 mm / 1.1°), 178 N (90°: 1.5 mm / 1.9° and 120°: 1.5 mm / 1.5°). Tibial internal rotation significantly increased after posterior cruciate ligament resection at 90° (1.9°) and 120° (2.2°). InterpretationJoint distraction forces after posterior cruciate ligament resection increased the tibial internal rotation, joint center gap, and varus ligament balance at flexion. These findings indicate that posterior cruciate ligament resection should increase the lateral gap more than the medial gap due to tibial internal rotation at flexion. (245 words).

Enclosing contour tracking of highway construction equipment based on orientation-aware bounding box using UAV

Construction equipment tracking of highway construction site can obtain the spatiotemporal location in real time and provide data basis for construction risk control. The complete 2D moving of construction equipment in surveillance videos could be spatially represented by the translation, rotation and size change of corresponding images. To describe the temporal relationships of these variables, this study proposes a construction equipment enclosing contour tracking method based on orientation-aware bounding box (OABB), where UAV surveillance videos are employed to alleviate the occlusion problem. The method balances the rotation insensitivity of horizontal bounding box and the complexity of pixel-level segmented contour, which has three modules. The first module integrates OABB into a deep learning detector to provide detected contours. The second module updates OABBs with Kalman prediction to output tracked contours. The third module manages IDs of multiple tracked contours for construction equipment motions. Five in-situ UAV videos including 4325 frames were employed as the evaluation dataset. The tracking performance achieved 2.657 degrees in angle error, 97.523% in MOTA and 83.243% in MOTP.

Fault diagnosis of rolling bearing under multiple working conditions based on multi-scale kernel convolution neural network

As the key component of wind turbine, the rolling bearing of gearbox plays an important role in the running process of wind turbine. However, in real-world situations, the working environment and conditions of wind turbine are very bad, resulting in a high failure incidence probability of gearbox rolling bearings. As mechanical vibration signals are typically non-stable, non-linear, and non-periodic, failure mode and its mapping relation to the raw signal signs become very complex. This paper aims to design a convolutional neural network based on multi-scale kernel depth and angular domain re-sampling intelligent fault diagnosis model to accurately diagnose the rolling bearing fault of gearbox. The model can effectively reduce the difference of vibration signals caused by rotational speed changes, and the inception model is used to divide the deep convolutional neural network into multiple branches to extract the features of rolling bearings in uniform or variable rotational speed states. After extracting the features, information fusion and fault classification are carried out. This combination model has excellent feature learning ability and classification performance. Moreover, the proposed method can adapt to fault diagnosis under variable speeds and multiple working conditions, and the robustness and accuracy of fault diagnosis are greatly improved.

Light-Controlled Rotational Speed of an Acoustically Levitating Photomobile Polymer Film.

In this work, we study the light-induced changes of the rotational speed of a thin photomobile film using a single-axis acoustic levitator operating at 40 kHz. In our experiments, a 50 μm thick photomobile polymer film (PMP) is placed in one of the nodes of a stationary acoustic field. Under the action of the field, the film remains suspended in air. By externally perturbing this stable equilibrium condition, the film begins to rotate with its natural frequency. The rotations are detected in real time by monitoring the light of a low power He-Ne laser impinging on and reflected by the film itself. During the rotational motion, an external laser source is used to illuminate the PMP film; as a consequence, the film bends and the rotational speed changes by about 20 Hz. This kind of contactless long-distance interaction is an ideal platform for the development and study of many electro-optics devices in microgravity and low-friction conditions. In particular, we believe that this technology could find applications in research fields such as 3D dynamic displays and aerospace applications.

An automated method for the assessment of the rice grain germination rate.

The germination rate of rice grain is recognized as one of the most significant indicators of seed quality assessment. Currently, grain germination rate is generally determined manually by experienced researchers, which is time-consuming and labor-intensive. In this paper, a new method is proposed for counting the number of grains and germinated grains. In the coarse segmentation process, the k-means clustering algorithm is applied to obtain rough grain-connected regions. We further refine the segmentation results obtained by the k-means algorithm using a one-dimensional Gaussian filter and a fifth-degree polynomial. Next, the optimal single grain area is determined based on the area distribution curve. Accordingly, the number of grains contained in the connected region is equal to the area of the connected region divided by the optimal single grain area. Finally, a novel algorithm is proposed for counting germinated grains. This algorithm is based on the idea that the length of the intersection between the germ and the grain is less than the circumference of the germ. The experimental results show that the mean absolute error of the proposed method for germination rate is 2.7%. And the performance of the proposed method is robust to changes in grain number, grain varieties, scale, illumination, and rotation.

EFEITO ROTACIONAL DO COLETE 3D NO TRATAMENTO DA ESCOLIOSE IDIOPÁTICA DO ADOLESCENTE

ABSTRACT Objective: To evaluate the axial correction capacity of the 3D brace in treating Adolescent Idiopathic Scoliosis (AIS). Methods: A retrospective study was carried out with 61 patients with AIS who obtained the 3D brace, between 2019 and 2022, in a laboratory that manufactures orthotics and orthopedic prostheses. These individuals underwent independent analysis of radiographic parameters by evaluating vertebral rotation using the Nash and Moe classification. The analyzed radiographs were taken in orthostasis before and after treatment with the 3D vest. Patients were divided into groups I and II-IV according to the Nash and Moe radiographic classification. Corrective capacity was estimated by assessing the degree of vertebral rotation before and after treatment. Results: Of the 61 patients evaluated, 36 (59%) had Nash and Moe grade I, and 25 patients grade II-IV before treatment. After treatment, 13 (21%) had grade II-IV, and 48 had grade I. Of the patients categorized as II-IV, 64% had improvement in the rotational profile. None clinical studies or radiographic parameter was associated with a change in rotational profile other than brace use (p=0.012). Conclusion: In the studied sample, treatment with the 3D vest promoted a change in vertebral rotation according to the Nash and Moe classification. The majority showed improvement in this parameter of evaluation of treatment of AIS. Level of Evidence III; Retrospective Study.

Ring-Masked Attention Network for Rotation-Invariant Template-Matching

To solve the rotational changes in matching localization of an underwater terrain image, this letter proposes the ring-masked attention network (RMANet), a model-driven deep network for rotational template-matching tasks. Since traditional convolutional neural networks cannot effectively encode rotational changes, we introduce a rotation-equivariant network to extract the rotation-equivariant features. This network determines the rotation of an image at the pixel level. Based on the rotation-equivariant features, we propose the ring-masked attention module (RMAM), which combines the idea of the ring projection transform with an attention mechanism to extract the rotation-invariant features that are independent of the orientation. The overall model combines the rotation-equivariant network with RMAM into an end-to-end network that can exploit both the feature-representation capability of the learning-based model and domain knowledge. Our experimental results show that, compared with popular approaches targeting rotational matching tasks, RMANet achieves performance gains in terms of both matching accuracy and running speed.

Study on the Compaction Performance and Its Key Influencing Factors of Asphalt Mixture Based on Intelligent Sensing Techniques

Real‐time and accurate compaction quality monitoring is one of the key steps in the pavement construction. In this study, the effect of roller passes and temperature on the compactness of asphalt mixtures and its uniformity is discussed using the semivariance function. Further, the indoor asphalt mixture gyratory compaction test was carried out based on the embedded SmartRock sensor, with the aim of monitoring the changes in rotation and contact forces between aggregates. In addition, the effect of temperature on the dynamic response of SmartRock is discussed, and the compaction mechanism of asphalt mixtures is investigated from a microscopic scale. It is found that compaction degree and uniformity are not always positively correlated with the number of roller passes and that excessive compaction leads to a decrease in compaction effect; meanwhile, the variation in the compactness of asphalt mixtures can be characterized by the dynamic response of SmartRock, which providing a feasible method for real‐time monitoring of the compaction process and optimization of the construction plan.

Finger Vein Recognition Based on Anatomical Features of Vein Patterns

Finger vein recognition is a promising biometric authentication technique that depends on the unique features of vein patterns in the finger for recognition. The existing finger vein recognition methods are based on minutiae features or binary features such as LBP, LLBP, PBBM etc. or from the entire vein pattern. However, the minutiae-based features cannot accurately represent the structural or anatomical aspects of the vein pattern. These issues with the minutia feature led to increased false matches. Recognition based on binary features have limitations such as increased false matches, sensitivity to the translation and rotation, security and privacy issues etc. A feature representation based on the anatomy of vein patterns can be an alternative solution to improve the recognition performance. In the IJCB 2020 conference, we showed that every finger vein image contains one or more of a kind of 4 special vein patterns which we refereed as Fork, Eye, Bridge, and Arch (FEBA). In this paper, we further enlarge this set to 6 vein patterns (F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> EB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> A) by identifying two variations in the Fork and Bridge vein patterns. Based on 6 anatomical features of the possible 6 vein patterns in a vein image, we define a 6 × 6 feature matrix representation for finger vein images. Since this feature representation is based on the anatomical properties of the local vein patterns, it provides template security. Further we show that, the proposed feature representation is invariant to scaling, translation, and rotation changes. The experimental results using two open datasets and an in-house dataset show that the proposed method has a better recognition performance when compared to the existing approaches with an EER around 0.02% and an average recognition accuracy of 98%.