Axial Line Research Articles

The distribution of Coronal Plane Alignment of the Knee (CPAK) phenotypes in the Malaysian population and their correlation with demographic variables

BackgroundOnly 80% of patients are satisfied with their outcomes post-TKA. Mounting attention has been paid to constitutional limb alignment and individualized alignment strategies in recent years. MacDessi et al. proposed the CPAK classification, which takes into account the patients’ arithmetic hip-knee-ankle axis (aHKA) and joint line obliquity (JLO). In this study, we aimed to establish local demographic data, compare them with published data, and assess their correlations with modifiable variables.MethodsA total of 500 end-stage osteoarthritic knees subjected to TKA were radiologically analyzed. The lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) were calculated from long limb radiographs before the aHKA and JLO were derived and a CPAK phenotype was assigned. Demographic data were harvested and analyzed for possible correlations.ResultsThere were 160 males (32%) and 340 females (68%), with a mean age of 66.42 years (range, 47–88). The mean MPTA was 85.8° (± 3.0)°, and the mean LDFA was 87.6° (± 2.4)°. The average aHKA was a varus of 1.8° (± 4.2)°, and the average JLO was 173.4° (± 3.45)°. The most common CPAK phenotype was Type 1 (43.4%). The Intraclass Correlation Coefficient demonstrated excellent reliability (> 0.9). No correlation existed between CPAK phenotypes and age, height, weight, or body mass index (BMI), but CPAK phenotype was significantly correlated with gender.ConclusionAn urban Malaysian population with osteoarthritic knees was found to be constitutionally varus, with the most common phenotype being varus aHKA with an apex-distal JLO. Constitutional alignment is not influenced by factors such as age, height, weight, or BMI.Level of EvidenceRetrospective Observational Study-III.

Features of the Structure and Dynamics of Water in the Northern Half of the Sea of Japan in Autumn-Winter Period According to Satellite Data and Ship Observation

The results of studies of the structure and dynamics of water in the zone of a large-scale cyclonic gyre in the northern half of the Sea of Japan are presented, where satellite IR images annually in the autumn-winter period most clearly show two areas of low temperatures, separated by the influx of warm Tsushima waters from Japan. The location of these thermal structures coincides with the location of the western and northern cyclonic gyres, which are inextricably linked with deep upwelling. During the autumn-winter periods 2019-2021 it has been established that deep upwelling in the northwestern part of the Sea of Japan extends from the bottom to the surface layer, focusing along the axial line passing through the Pervenets Rise and the Bersenev and Vasilkovsky ridges in the area of 42° N. between 132°E and 135.5° E. The western cyclonic gyre, located in the western part of the large-scale cyclonic gyre in the region of the considered deep upwelling, is a large topographic eddy. In the northern part of the large-scale cyclonic gyre, deep upwelling is confined to the continental clone, and the small northern cyclonic gyre is also located there. It is assumed that in the autumn-winter period the interaction of anticyclones that form vortex belts with cyclonic gyres leads to an increase in deep circulation. The peculiarity of the variability of the speed of deep currents - an increase from October to March, is probably due to the nature of the development of vertical and transverse horizontal circulation in the system of cyclonic gyres - vortex belts as a result of the intensification of deep upwelling with increased winds from the northern directions in winter.

Geometric Parameter Optimization for Axial Modification in Helical Gear Form Grinding

During the axial modification in helical gear form grinding, the contact line between the grinding wheel and the gear constantly changes, and the additional radial motion can cause a “tooth surface twist” phenomenon. An optimization method for tooth surface twist error was proposed to address this. Based on the gear meshing principles, a mathematical model for axial modification in form grinding was established to solve for the instantaneous contact lines at various positions on the actual modified tooth surface. By analyzing the influence of the grinding wheel installation angle on the axial modification contact line, an optimization model was constructed to reduce the twist of the transverse profile, reduce the twist of the flank profile, reduce the helix deviation, and improve the form grinding efficiency. The practical implications of this research are significant, as the Particle Swarm Optimization (PSO) algorithm was employed to optimize the form grinding parameters, leading to a method that effectively reduced tooth surface twist error and improved the form grinding accuracy of the modified tooth surface.

Acanthus ornament generation using layout subdivisions with parameterized motifs

AbstractAcanthus ornaments frequently adorn Western architectural designs. The placement of these motifs varies according to the decorative object, with some having motifs arranged in a grid pattern. In this study, we propose a procedural modeling system aimed at generating acanthus ornaments on a planar surface. The proposed approach initially establishes the layout of boundary grids for acanthus motifs by subdividing the target surface into nonuniform grids. Subsequently, the medial axis line of the acanthus motif is generated to optimally conform to each boundary grid, employing a parameterized representation of deformable motifs. The three‐dimensional motif shapes are ultimately constructed from the medial axis, with the shape parameters adjusted to improve aesthetic appeal. The proposed system generates various acanthus ornaments through rule‐based layout subdivisions, offering users the option to select their preferred design while adjusting the motif shapes with a few manual parameters.

Three-Dimensional Bowing Measurement of Distal Femur at Actual Size and Clinical Implications of Total Knee Arthroplasty.

Background and Objectives: To assess femoral shaft bowing (FSB) in coronal and sagittal planes and introduce the clinical implications of total knee arthroplasty (TKA) by analyzing a three-dimensional (3D) model with virtual implantation of the femoral component. Materials and Methods: Sixty-eight patients (average age: 69.1 years) underwent 3D model reconstruction of medullary canals using computed tomography (CT) data imported into Mimics® software (version 21.0). A mechanical axis (MA) line was drawn from the midportion of the femoral head to the center of the intercondylar notch. Proximal/distal straight centerlines (length, 60 mm; diameter, 1 mm) were placed in the medullary canal's center. Acute angles between these centerlines were measured to assess lateral and anterior bowing. The acute angle between the distal centerline and MA line was measured for distal coronal and sagittal alignment in both anteroposterior (AP) and lateral views. The diameter of curve (DOC) along the posterior border of the medulla was measured. Results: The mean lateral bowing in the AP view was 3.71°, and the mean anterior bowing in the lateral view was 11.82°. The average DOC of the medullary canal was 1501.68 mm. The average distal coronal alignment of all femurs was 6.40°, while the distal sagittal alignment was 2.66°. Overall, 22 femurs had coronal bowing, 42 had sagittal bowing, and 15 had both. Conclusions: In Asian populations, FSB can occur in coronal, sagittal, or both planes. Increased anterolateral FSB may lead to cortical abutment in the sagittal plane, despite limited space in the coronal plane. During TKA, distal coronal alignment guides the distal femoral valgus cut angle, whereas distal sagittal alignment aids in predicting femoral component positioning to avoid anterior notching. However, osteotomies along the anterior cortical bone intended to prevent notching may result in outliers due to differences between the distal sagittal alignment and the distal anterior cortical axis.

Effect of Posterior Cruciate Ligament Resection on Gap Balancing in Robot-assisted Total Knee Arthroplasty.

Retention or sacrifice of the posterior cruciate ligament (PCL) is one of the most controversial issues while performing total knee arthroplasty (TKA). This study aimed to evaluate the impact of PCL resection on flexion-extension gaps, femoral component rotation, and bone resection amounts during robot-assisted TKA. This prospective study included 40 patients with knee osteoarthritis who underwent robot-assisted posterior-stabilized (PS) TKA between September 2021 and February 2022. Of the patients, 75% were women (30/40) with a mean age and BMI of 72.6 years and 27.4 kg/m2, respectively. The guidance module and camera stand assembly were used to capture gaps before and after PCL resection. Measurements of femoral component rotation and bone resection amounts were made in cruciate-retaining (CR) TKA mode and PS-TKA mode. After PCL resection, the mean change in the medial and lateral compartments of flexion gaps increased by 2.0 and 0.6 mm, respectively (p < 0.001). Compared with the CR-TKA mode group, the bone resection amounts of the medial posterior condyle and the lateral posterior condyle in the PS-TKA mode group decreased by 2.0 ± 1.1 and 1.1 ± 1.1 mm, respectively, and the external rotation of the femoral prosthesis relative to the posterior condylar axis and trans-epicondylar line was reduced by 1.0° ± 1.3° and 1.2° ± 1.6°, respectively (p < 0.001). The release of the PCL did not affect the extension gap, but significantly increased the flexion gap. Moreover, the increases in the medial flexion gap were greater than those of the lateral flexion gap. After PCL resection, less external rotation of the femoral prosthesis and fewer bone cuts of the posterior femur were needed in PS-TKA.

Structural response analysis of a solid rocket motor charge under temperature and internal pressure loads

To study the structural integrity of a solid rocket motor under low temperature load, internal pressure load, and two combined loads, based on the linear viscoelastic model, the structural response of a solid rocket motor under low temperature load, internal pressure load and two combined loads were analyzed by ANSYS finite element software, and the temperature field and strain field of charge loading were obtained. The Von Mises strain distribution of the solid rocket motor along the axial characteristic line is obtained. The results are: Under the combined action of low temperature load, internal pressure load, and two kinds of loads, the maximum Von Mises strain appears at the transition position between the blade joint and the barrel section, which is the most dangerous position for charging.

Mid-infrared optical coherence tomography with MHz axial line rate for real-time non-destructive testing

Non-destructive testing (NDT) is crucial for ensuring product quality and safety across various industries. Conventional methods, such as ultrasonic, terahertz, and x-ray imaging, have limitations in terms of probe-contact requirement, depth resolution, or radiation risks. Optical coherence tomography (OCT) is a promising alternative to solve these limitations, but it suffers from strong scattering, limiting its penetration depth. Recently, OCT in the mid-infrared (MIR) spectral region has attracted attention with a significantly lower scattering rate than in the near-infrared region. However, the highest reported A-scan rate of MIR-OCT has been 3 kHz, which requires long data acquisition time to take an image, unsatisfying industrial demands for real-time diagnosis. Here, we present a high-speed MIR-OCT system operating in the 3–4 µm region that employs the frequency-swept spectrum detection in OCT technique based on time-stretch infrared spectroscopy. By integrating a broadband femtosecond MIR pulsed laser operating at a repetition rate of 50 MHz, we achieved an A-scan rate of 1 MHz with an axial resolution of 11.6 µm, a 10 dB roll-off depth of about 700 µm, and a sensitivity of 55 dB. As a proof-of-concept demonstration, we imaged the surface of substrates covered by highly scattering paint coatings. The demonstrated A-scan rate surpasses previous state of the art by more than two orders of magnitude, paving the way for real-time NDT of industrial products, cultural assets, and structures.

Technical design of an axial injection low-energy carbon beam line

Technical design of an axial injection low-energy carbon beam line

STUDY OF DEFORMABILITY OF THE LARGE-SPAN ROOF STRUCTURAL SYSTEM IN THE FORM OF AN ASYMMETRICAL SHELL

The scientific article is devoted to a complex study of deformability of saddle-type shell of negative Gaussian curvature of a public object that has been in operation for a long time for further general restoration of the building’s roofing system. The authors have developed a specific algorithm for conducting experimental research, providing additional static load on a shell at the lower point of the gentle axial line of the supporting arches. To smoothly carry out the loading procedure, we mounted containers in barrel form on the roof surface and gradually filled them with water. We carried out an experimental evaluation of the bearing capacity of the shell with the determination of the redistribution of forces along the length of the section in the lower zone of the conventionally outlined arch. The experimental test results revealed that the deformability of the shell surface under short-term loading did not exceed 2.0 mm, and, under long-term loading, it was no more than 4.0 mm. Analysis of the qualitative features of structure deformation shows that the displacement of the roof’s points, located symmetrically to the vertical axis, has the opposite sign to the sign of the displacement of the actual ‘saddle’ point (the case of symmetrical deformation). We conducted a numerical verification of the behaviour of the investigated structure by forming a detailed finite element spatial model of the shell. Comparison of the results of numerical calculation with the results of field tests shows the coincidence of qualitative and quantitative parameters, which, in turn, characterises the developed theoretical model as fully adequate and suitable for analysing the stress-strain state of similar large-span structural systems. Based on the results of comprehensive theoretical and experimental research, we made proposals for the further restoration of the roofing structure with the limitation of the self-weight of the covering to 1 kN/m2. Engineers and scientists can use the research results to reconstruct similar authentic structural systems. Keywords: calculation, restoration, loading, deflection, shell, negative Gaussian curvature.

MSCS-ICP: point cloud registration method using multi-view spatial coordinate system–ICP

The effectiveness of point cloud registration critically determines three-dimensional (3D) reconstruction accuracy involving multi-view sensors. We introduce a multi-view point cloud registration method based on multi-view spatial coordinate system–ICP to solve the problem of 3D point cloud registration from different viewpoints. By integrating a spatial rotation axis line, our method successfully establishes the spatial coordinate system tailored for multi-view sensors, ensuring that 3D point clouds derived from various perspectives are optimally positioned initially. We employ the ICP technique for point cloud merging, facilitating a seamless transition from coarse to refined registration of these multi-view 3D point clouds. During the process of spatial rotation axis line fitting, we present a Ransac-based algorithm tailored for axis line fitting that effectively removes outliers, thus significantly improving the fitting precision. Experimental results from a standard sphere reconstruction reveal that within a measurement scope of 1.3–1.9 m, our proposed method boasts a maximum error of just 0.069 mm, an average absolute error of 0.039 mm, and a root mean square error of 0.043 mm. The speed of our point cloud registration outpaces that of alternative methods. Our method notably elevates the precision and velocity of 3D point cloud registration across diverse views, demonstrating commendable adaptability and resilience.

The fluidization behavior of particles in supercritical water fluidized bed: A region-dependent analysis

The distribution and fluctuation of particle concentration in a supercritical water fluidized bed (SCWFB) are studied using a specially-designed capacitance probe measurement system. The measurement error of capacitance probe system is 2.48%. Results show that the particle concentration at the axial line fluctuates largely with time and the fluctuation is weakened when increasing the distance from axial line or decreasing particle diameter. At Uf/Umb=1.5, the largest difference between particle concentrations is 0.026, 0.04, 0.082 when the particles with a diameter of 0.124 mm, 0.198 mm, 0.235 mm are used, indicating a larger non-uniformity of larger particles. The probability density of local particle concentration mainly follows a unimodal distribution with the peak at right side. The main frequency of SCWFB ranges from 1.39 Hz to 2.73 Hz in this experiment and the main frequency decreases when larger particles are used.

Fully automated measurement of femoral neck axis line in anatomical coordinate system using CT images.

The femoral neck is the most vulnerable site for fractures within the hip joint. Due to its complex three-dimensional structure and special blood supply mechanism, the treatment of femoral neck fractures is difficult and the healing probability is low. Using computers to accurately and automatically locate the femoral neck axis can detect the density of femoral neck, the neck-shaft angle and the anteversion angle, which effectively assists in the prevention and treatment of femoral neck fractures. Additionally, the traditional femoral neck axis positioning schemes have limitations in accuracy, automation and assistance to bone density measurement. Therefore, this paper proposes a new fully automatic femoral neck axis positioning method. First, the coronal plane's three-dimensional reconstruction highlights the details of the target bone, and then designs a coarse localization module based on multi-scale template matching to obtain the rough range of the femoral neck axis. Then, a detailed localization module based on the femoral neck virtual slices is used to obtain the contour centers and accurately locates the three-dimensional femoral neck axis. This method has been validated in comparison with the manual measurement method. Experimental results revealed that the extracted femoral neck axis in this study can achieve automation, ensure accuracy, and avoid subjective effects effectively and has the potential value to be applied in the prevention and treatment of femoral neck fractures.

Thermocapillarity transition-induced unconventional thermal behavior and dilution in laser welding of metals with dissimilar sulfur content

An enhanced three-dimensional transient Thermal-Fluid-Dilution model, integrating a sub-model that accounts for surface tension, is proposed to investigate the unconventional thermal behavior and dilution induced by the surface-active element (sulfur) during the laser joining process of 304SS with higher sulfur content and pure nickel with lower sulfur content. Surface tension is modeled as a function dependent on local temperature and the concentration of the surface-active element (sulfur) at the free surface. The temperature and sulfur-dependent surface tension initially generate an unconventional driving force, subsequently leading to the transitions of heat transfer, flow pattern, and species dilution. Specifically, the inclusion of the sulfur effect results in a redistribution of larger surface shear stress along the transition boundary, causing unconventional flow behavior. The temperature coefficient of surface tension (TCST) is the coexistence of TCST (-) and TCST (+), leading to a novel flow pattern with combined inward-outward flows. Moreover, the anomalous flow exhibits observed phenomena such as the rotation of the major axis (RA) and center line shift (CLS) within the melt pool, showing more reasonable simulated melt pool dimensions when accounting for the sulfur effect. Additionally, the dilution model integrated with the unconventional flow pattern presents a more uniform concentration distribution compared to the conventional dilution. Finally, the simulated distribution of alloy elements is validated effectively by experimental data obtained from Energy Dispersive Spectrometer (EDS) analysis.

Development of a robot-assisted reduction and rehabilitation system for distal radius fractures.

Background: Closed reduction is the preferred treatment for distal radius fractures. However, it requires a multiple experienced medical staff and manually maintaining stable traction is difficult. Additionally, doctors cannot assess the reduction status of a fracture in real-time through radiographic images, which may lead to improper reduction. Furthermore, post-fracture complications such as joint adhesion, stiffness, and impaired mobility pose a challenge for the doctors. So it is necessary to optimize the treatment process of the distal radius fracture through technological means. Methods: A robot-assisted closed reduction and rehabilitation system, which could assist doctors throughout the entire process of reduction, fixation, and rehabilitation of distal radius fractures, was developed. A mechanical system, composed of two grippers and a cooperative robotic arm, was used to grasp and tract the affected limb. A doctor controlled the robot through a joystick console and Windows application program. A biplane radiographic device was integrated into the system, which is not only convenient for doctors to view radiographic images of the fracture at any time but also for them to select the rotation axis of the wrist on the images before reduction and rehabilitation. Important information including the anteroposterior and lateral radiographic data and force and position parameters during the reduction and rehabilitation process were displayed on a graphic user interface. Results: Experimental results showed that the proposed robotic system can meet the technical requirements for the reduction and rehabilitation of distal radius fractures, all the rotation angles could be achieved, a maximum force of more than 50N could be achieved in all traction directions, and the error in selecting the wrist joint rotation axis line using radiographic images was less than 5mm. Conclusion: The developed robot-assisted system was shown to be suitable for closed reduction and rehabilitation of distal radius fractures, contributing a potential improvement in the quality of the procedures.

Observation of the dynamic evolution process of vacuum arc microscopic particles based on the emission spectrum principle

The distribution of microscopic particles directly affects the recovery of the post arc insulating medium and determines whether the fault current can be interrupted. Based on the principle of vacuum arc emission spectrum, a high-speed spectrum observation platform was built to study the distribution of microscopic particles during the arc burning, and the axial and radial spectral line intensity and density distributions of atoms and ions under different current amplitudes were obtained. The results show that the CuI spectral line intensity has two peaks near the cathode and anode, while in the arc column it is relatively low. The peak of the CuI spectral line intensity near the electrode is caused by electrode evaporation. The peak duration of the CuI spectral line intensity near the cathode is always longer than that near the anode. The CuII spectral line intensity is lower, appears later and disappears earlier, which in the arc column increased obviously, compared with CuI. The CuII density near the cathode is higher than that near the anode, and the CuII density in the arc column is higher than in the two electrodes, which is similar to the axial distribution of electron density. The radial distribution curve of CuI and CuII density is similar to the radial distribution curve of spectral line intensity, and displays the characteristics of a high center and low edge in the radial direction of the arc gap. The difference is that the width of the atomic spectral line is larger than that of the corresponding ionic spectral line, the distribution curve of the ionic spectral line is smooth and symmetrical, and the radial attenuation rate of the CuII density is larger than that of the corresponding CuI. This reflects the ionization of atoms and the effect of magnetic fields. The radial and axial distribution of the particle density is opposite to that of the excitation temperature. Electrode emission will first affect the atom formation.

Key factors for increased tip-apex distance when treating intertrochanteric fractures with InterTAN nails.

The tip-apex distance is a key factor in predicting implant cut-out after intramedullary fixation for intertrochanteric fractures. This study aimed to evaluate the factors associated with an increased tip-apex distance when treating intertrochanteric fractures using an InterTAN nail. We retrospectively analyzed patients with intertrochanteric fractures who underwent InterTAN nail insertion between January 2017 and March 2022 at our hospital. Medical and radiological data were collected. Measurements of preoperative factors and postoperative factors were performed accordingly. Multivariate logistic regression analysis was performed to determine the statistically significant variables of the tip-apex distance. This study included 102 patients with intertrochanteric fractures. The average tip-apex distance measured 22.4 ± 7.1mm, ranging from 9.3 to 48.0mm. The length of the femoral neck on the non-fractured side, lag screw placement in the sagittal plane (center-inferior, superior) and coronal plane (posterior), and the angle between the line of the proximal nail axis and the femoral long axis were identified to be statistically significant factors for the tip-apex distance. To obtain a shorter tip-apex distance, we recommend a medial trochanteric entry point to minimize the angle between the line of the proximal nail axis and the femoral long axis. Additionally, sufficiently deep central insertion of the lag screw was advised in both the sagittal and coronal planes.

Single radio frequency bucket injection in the 88-Inch Cyclotron using a pulsed high voltage chopper.

A single radio frequency bucket of the 88-Inch Cyclotron is filled using a fast chopper located in the axial line. The bucket then accelerates until it reaches the deflector, at which point, it is extracted as a train of bunches. This phenomenon can be attributed to the characteristic multi-turn extraction of the cyclotron and, by simplifying the complex dynamics of a cyclotron, corresponds to the conceptual transfer function of the cyclotron. The confirmation of the single radio frequency bucket injection was achieved by operating the cyclotron in the third harmonic mode and observing the absence of intermediate bunches during the multiple-bunch extraction.

Calibration of Fisheye Camera with Co-linear Constraint of the Main Optical Axis and Epipolar Line Orthogonality-Transverse Axis

Calibration of Fisheye Camera with Co-linear Constraint of the Main Optical Axis and Epipolar Line Orthogonality-Transverse Axis

Use of an optical profilometer to measure the aerodynamic shape and the twist of a wind turbine blade

This study introduces a metrological approach to measure the aerodynamic shape and the twist of a wind turbine blade. The optical profilometer measurement technique used is laser triangulation. A camera records the image of a line projected onto a section of the blade and, by reconstructing the airfoil shape, the twist angular position of the profile with respect to the axial line of the blade is determined. This methodology is applied to test different sections of a Wortmann FX 63-137 airfoil with a length of 1700 mm. The results of the aerodynamic shape and twist angle are quantitatively verified by comparing them with the ideal or design values. The reconstruction process achieved a resolution of 0.06 mm, and measurement errors in the twist angular position were less than 0.1°. The presented method is efficient, accurate, and low cost to evaluate the blade profiles of low-power wind turbines. However, due to its easy implementation, it is expected to be able to measure any full-scale wind blade profile up to several meters in length.