Cylindrical Axis Research Articles

Numerical Study on the Relationship between the Dominant Frequency of Blasting Vibration and the Development of Plastic Zone in Cylindrical Charge

Blasting vibration is a widely studied harmful effect of rock blasting excavations. Many factors affect its dominant frequency, which makes analyzing, evaluating, and predicting it difficult. This study explored the factors influencing the dominant frequency of blasting vibrations in the case of a spherical charge. Based on symmetry, a theoretical analysis in terms of a spherical explosion source is generally sufficient to describe a cavity excited by a spherical explosion charge. The elastic cavity radius and the dominant frequency of vibration induced by the spherical blasting source are closely related. However, there is a lack of relevant research on cylindrical charges. Therefore, a calculation model for a single-hole cylindrical charge was established. There is a relationship between the corresponding dominant frequency and the range of the plastic zone. The results indicate that the dominant frequency of the blasting vibration for both cylindrical and spherical charges is closely related to the range of the plastic zone formed by the rock blasting. As the elastic cavity radius increases, both the zero-crossing and the dominant Fourier frequencies decrease, and the amplitude spectrum shifts to lower frequencies. However, increasing the cylindrical charge diameter causes more changes in the plastic zone in the direction perpendicular to the cylindrical explosive axis. Moreover, increasing the charge length causes more changes in the plastic zone along this axis. It is therefore difficult to identify a unique dimensional parameter that characterizes the range of the plastic zone formed by the blasting. Because the plastic zone around a cylindrical charge is less regular than around a spherical charge, the charge weight Q is a more favorable parameter than the elastic cavity radius a when used as the main influencing factor and in an attenuation analysis for the dominant frequency of cylindrical charge blasting.

Structure of test magnetic fields and charged particle motion around the Hayward spacetime

A configuration of a test magnetic field in Hayward spacetime is obtained by solving Maxwell's equation with the Hayward metric as the background. The magnetic field lines show a dipole looplike configuration in the regular Hayward interior, and tends to an asymptotically uniform structure away from the cylindrical axis. The motion of charged particles is then studied in this spacetime. The parameters and stability of circular orbits on the equatorial plane are studied. Aspects of nonequatorial motion are also studied.

Nanoporous Vesicular Membranes of Amphiphilic Polymers Containing Trans / Cis Isomers

Nanoporous Vesicular Membranes of Amphiphilic Polymers Containing <i>Trans</i> / <i>Cis</i> Isomers

3D Printed Schematic Model for Extraocular Muscles teaching

There are many difficulties a student or educator can present in the anatomy course. Technological advances and availability of new tools have provided alternatives to improve the learning method.A 3D model of an orbit and ocular globe (OG) was designed and 3D printed. It consisted of a roof, floor, medial and lateral walls, and a posterior wall. The superior and inferior orbital fissures were represented, as well as the common tendinous ring (Zinn's) and the optic canal from which a cylindrical axis extends in a 45° angle, representing the optic nerve (ON). At the end of this axis, a sphere an enarthrosis sphere simulates the OG. The medial wall is parallel to the OG’s axis, while the lateral wall is almost parallel to the ON’s axis. The OG was formed with polygons to allow better perception of the movements. The center of the sphere attached to the ON matches the center of the OG, resulting in the OG rotating without moving within the orbit.Six holes were made in the OG, in which elastic threads were placed. In the anterior half of the OG, a hole for the superior, inferior, medial and lateral surfaces was made, corresponding to the insertions of the superior rectus (SR), inferior rectus (IR), medial rectus (MR), and lateral recti muscles (LR) respectively. On the lateral surface of the posterior half of the OG, a hole in the superior region was made for the insertion of the superior oblique (SO) and another in the inferior region for the insertion of the inferior oblique (IO). The four rectus muscles originate from the annulus of Zinn, and represented with holes that cross the posterior wall of the orbit in the common tendinous ring at the four points of insertion.In the medial wall of the orbit, at the superior anterior corner, a trochlea was made, through which the thread representing the SO passes and is anchored to the posterior wall through a hole that is superior to the hole for the SR. On the same wall, but in the interior anterior corner of the orbit, we designed a hole to anchor the thread that represents the IO. The angles between the axes of the oblique muscles, recti muscles, and the axis of the OG were kept as close to reality as possible. In the model, the axis between the recti muscles and the OG’s is 20° (human orbit is 23°) and between the oblique muscles and the OG’s is 70° (human orbit is 51°).The design allows an internal rotation when tightening the threads that are inserted in the superior half of the OG (SR, SO); if the inferior half are tightened (IR, IO), it causes an external rotation; if the recti are tightened, adduction occurs (except for the LR); if those representing the obliques and the LR are tightened, an abduction occurs; if those inserted in the anterior half of the OG (SR, IR, MR, LR) are tightened, the movement corresponding to its name is produced, and if those inserted in the posterior half are tightened, the movement occurs opposite to what their names indicate (SO, IO).The model is effective and makes learning easier. Student perception has not been surveyed yet. Future version may improve the angle between the oblique’s and the OG’s axis. Pathological finding can also be exemplified.

Ultrasensitive and Broadband Optical Toroidal Modes in all‐Dielectric Nanostructures (Laser Photonics Rev. 16(3)/2022)

Toroidal Metamaterials In article number 2100404, Hui-Hsin Hsiao, and Ai-Yin Liu demonstrate optical toroidal dipole and anapole metamaterials through the designs of periodic amorphous silicon nano-pillars embedded in a spin-on glass layer. Upon normal incidence of plane wave, the transverse toroidal moment, stemming from a complete head-to-tail configuration of the magnetic dipole moments within each individual nanopillar, are excited in optical regime. The toroidal response can be enhanced and spectrally tuned by elongating cylindrical axis perpendicular to the light polarization and exhibit ultrahigh refractive index sensitivity compared to other multipoles.

An Interference Inspection Algorithm of Limb and Hexapod Frame in the Treatment of Lower Limb Deformity

Pre-operative correction trajectory planning is one of the important aspects of deformity correction. Avoidance of limb-frame interference is essential to verify the implementability of the preplanned correction trajectory, as well as to maintain the continuity and security of the correction strategy. In this study, a novel interference inspection algorithm is developed to investigate the interaction of the limb and hexapod frame in the treatment of lower limb deformities. The algorithm is built on a minimum distance model of the cone frustum busbar and cylindrical axis using vector analysis. A predefined trajectory is generated by Cartesian coordinate path control. Subsequently, an interference case is performed through numerical simulation and motion simulation. The results show that the conclusion of numerical simulation and motion simulation is consistent, which prove the feasibility of the algorithm. The results also show that it is possible to identify the riskiest struts, which are prone to interfere with the limb, and the riskiest positions. The proposed algorithm can support the clinician in selecting the suitable frame configuration to avoid interference. The algorithm solves the problem that the interference can only be judged by clinical observation in the clinic.

An improved posture evaluation method for cylindrical intersecting holes on large aerospace components based on monocular vision

Cylindrical intersecting holes (CIHs) are common connection and location reference features in the assembly of large aerospace structures such as missiles and rocket cabins. The posture accuracy of assembly holes significantly impacts the relative position accuracy of joined parts and the fatigue strength of the finished product. At present, monocular vision measurement is widely used in the automatic drilling of assembly holes due to its integration simplicity and lower cost, but in most research, only the front face edge of the hole is used in the measurement model, and the hole end surface is usually assumed to be plane, which inevitably leads to precision loss. In this research, a novel posture measurement method for CIHs is proposed. Firstly, by introducing an ambiguity removal strategy, a coarse posture estimation method based on the plane hypothesis of the two end surfaces of CIHs is suggested. Secondly, considering that there is no simple explicit expression for a CIH’s edge, it is difficult to adopt the conventional model projection-based pose optimization method. In view of this, the 3D points corresponding to the edge pixels of the CIHs’ image are derived, and the pose optimization model is established by minimizing the deviations between the distance from the points to the CIHs’ axis and the hole radius. Moreover, to better control the direction parameters of CIHs during the global optimization process, the approximately perpendicular and intersection constraints between the CIHs’ axis and cylindrical component axis are involved in the solution. The effectiveness of the posture measurement method is verified by comparative experiments with current methods and coordinate measuring machine, which demonstrates improvements in both measurement accuracy and robustness.

Predicting extreme anisotropy and shape variations in impact testing of tantalum single crystals

Recent Taylor cylinder impact tests carried out for Ta single crystals showed strong variations in dimensional changes for different crystallographic directions aligned with the cylindrical axis. In order to capture the effect of crystallography on the deformation characteristics and final shapes of the impacted cylinders, a single crystal material subroutine is adapted and embedded in the solid mechanics/dynamics Finite Element solver Abaqus to simulate the aforementioned single crystal Ta Taylor impact experiments. Details of the coupled model implementation, and insights on the role played by single crystal anisotropic flow on the deformation behavior across a broad range of strain rates and temperatures for different single crystal orientations are presented and discussed. We demonstrate the predictive capability of the adopted crystal plasticity model to capture the significant role played by crystal orientation-induced anisotropy, as well as strain hardening and adiabatic heating, on the dynamic deformation response of crystalline materials. This re-emphasizes the need of microstructure-aware models to improve the accuracy of simulations for high-consequence engineering design.

Ultrasensitive and Broadband Optical Toroidal Modes in all‐Dielectric Nanostructures

AbstractDynamic toroidal dipole (TD) with its peculiar characteristic of broken space‐inversion and time‐reversal symmetries plays an important role in the fundamental physics of light–matter interaction. Here, TD metamaterials comprised of amorphous silicon nanopillar arrays embedded in spin‐on‐glass layer are experimentally demonstrated. Upon normal incidence of plane wave, the transverse toroidal moment and the associated anapole‐like state are excited in optical regime. The strong TD response stems from a complete head‐to‐tail configuration of the magnetic dipole moments within each individual nanopillar. Both the experimental and simulation results show that such TD mode sustains a large structural tolerance and can be spectrally tuned by elongating the cylindrical axis perpendicular to the light polarization, corresponding to a cross‐sectional variation from circular to elliptical shapes. The excited TD mode is found to exhibit ultrahigh refractive index sensitivity compared to other multipoles, resulting in a sensitivity of 459 nm (470 nm) per external refractive index change in the experiment (calculation). This approach provides a simple and straightforward path in realizing toroidal metamaterials and establishes a new flat‐optics platform for realizing active metadevices, sensors, and nonlinear nanophotonics.

Ten-year longitudinal investigation of astigmatism: The Yamagata Study (Funagata).

Despite numerous investigations into ocular or corneal astigmatism, the dynamic nature of astigmatism remains poorly understood. To reveal potential associations between age and astigmatism, 264 Japanese participants who underwent systemic and ophthalmological examinations in Funagata Town (Yamagata Prefecture, Japan) were evaluated over a 10-year period. Astigmatism was evaluated with regard to the cylinder power, cylinder axis, and vector analyses. Whereas the refractive cylinders showed age-related increases in patients in their 40s to 60s, the corneal cylinders did not change over 10 years. Nevertheless, cylindrical axis of the cornea demonstrated a continuous shift toward against-the-rule (ATR) astigmatism. Vector analyses revealed that the astigmatic shift toward ATR progressed continually after patients reached their 40s, although the shift did not accelerate with age. These novel insights may pave the way for the development of potential strategies for vision correction, including refractive surgeries, and vision-quality maintenance in the elderly.

Accuracy of Patient-Specific Instrument for Cylindrical Axis Implementation in Kinematically Aligned Total Knee Arthroplasty.

In kinematically aligned total knee arthroplasty (KA-TKA), the cylindrical axis (CA) is very important in restoring the native joint line and kinematics of the pre-arthritic knee. This study aimed to determine the accuracy of patient-specific instrument (PSI) for restoring the CA for femoral bone resection in KA-TKA. Thirty KA-TKAs were performed using a computed tomography (CT)-based PSI system. Data from preoperative CT were reconstructed into three-dimensional (3D) models using 3D-planning software. The CA was created by connecting the centers of each virtual sphere to the medial and lateral femoral condyles using computer software. Femoral bone resection of the distal and posterior condyles was performed parallel to the sagittal planes of the CA. The thickness of the CA-referenced bone resection was determined based on the thickness necessary for the respective regions of the femoral component. The PSI was manufactured to locate the guide pin for a conventional cutting block. The accuracy of PSI for KA-TKA was evaluated as the absolute error between the preoperatively predicted thickness and the intraoperative measurements in each of the four regions, as well as the difference in error between distal-medial (DM) and posterior-medial (PM) and between distal-lateral (DL) and posterior-lateral (PL). The differences in thickness of bone cut in the DM, DL, PM, and PL were 0.79 ± 0.39 mm (range, -1.20 to 1.50), 0.70 ± 0.42 mm (range, -1.50 to 1.50), 0.80 ± 0.46 mm (range, -0.80 to 1.50), and 0.75 ± 0.47 mm (range, -2.10 to 1.40), respectively. There was no significant difference in the thickness error between DM and PM (p = 0.959) and between DL and PL (p = 0.812). In KA-TKA, PSI was effective for accurate femoral bone resection based on virtually planned thickness.

Onset of vortex shedding around a short cylinder

This paper presents results of three-dimensional direct numerical simulations (DNS) and global linear stability analyses of a viscous incompressible flow past a finite-length cylinder with two free flat ends. The cylindrical axis is normal to the streamwise direction. The work focuses on the effects of aspect ratios (in the range of $0.5\leq {\small \text{AR}} \leq 2$ , cylinder length over diameter) and Reynolds numbers ( $Re\leq 1000$ based on cylinder diameter and uniform incoming velocity) on the onset of vortex shedding in this flow. All important flow patterns have been identified and studied, especially as ${\small \text{AR}}$ changes. The appearance of a steady wake pattern when ${\small \text{AR}} \leq 1.75$ has not been discussed earlier in the literature for this flow. Linear stability analyses based on the time-mean flow has been applied to understand the Hopf bifurcation past which vortex shedding happens. The nonlinear DNS results indicate that there are two vortex shedding patterns at different $Re$ , one is transient and the other is nonlinearly saturated. The vortex-shedding frequencies of these two flow patterns correspond to the eigenfrequencies of the two global modes in the stability analysis of the time-mean flow. Wherever possible, we compare the results of our analyses to those of the flows past other short- ${\small \text{AR}}$ bluff bodies in order that our discussions bear more general meanings.

The medial condylar wall is a reliable landmark to kinematically align the femoral component in medial UKA: an in-silico study

PurposeKinematic alignment (KA) aligns the femoral implant perpendicular to the cylindrical axis in the frontal and axial plane. Identification of the kinematic axes when using the mini-invasive sub-quadricipital approach is challenging in unicompartmental knee arthroplasty (UKA). This study aims to assess if the orientation of condylar walls may be suitable for use as an anatomical landmark to kinematically align the femoral component in medial UKA. It was hypothesised that the medial wall of the medial condyle would prove to be a reliable anatomical landmark to set both the frontal and axial alignment of the femoral component in medial UKA.Methods73 patients undergoing medial UKA had pre-operative CT imaging to generate 3D models. Those with osteophytes that impaired visualisation of the condylar walls were excluded. 28 patients were included in the study. The ideal KA was determined using the cylindrical axis in the frontal and axial plane. Simulations using the medial wall of the medial condyle (MWMC) and the lateral wall of the medial condyle (LWMC) were performed to set the frontal alignment. To set the axial alignment, the MWMC, LWMC, medial wall of the lateral condyle (MWLC), and medial diagonal line (MDL) anatomical landmarks were investigated. Differences between the ideal measured KA values and values obtained using landmarks were investigated.ResultsUse of the MWMC let to similar frontal alignment compared to the ideal KA (2.9° valgus vs 3.4° valgus, p = 0.371) with 46.4% (13/28) of measurements being le 1.0° different from the ideal KA and only 1 simulation with greater than 4.0° difference. Use of the MWMC led to very similar axial alignments compared to the ideal KA (0.5° internal vs 0.0°, p = 0.960) with 75.0% (21/28) of measurements being le 1.0o different from the ideal KA, and a maximum difference of 3.0°. Use of the MWLC and MDL was associated with significant statistical differences when compared to the ideal KA (p < 0.001 for both).ConclusionsThe native orientation of the medial condylar wall seems to be a reliable anatomical landmark for aligning the femoral component in medial KA UKA in both the axial plane and frontal planes. Other assessed landmarks were shown to not be reliable. Clinical and radiographic assessments of the reliability of using the MWMC to set the frontal and axial orientation of the femoral component when performing a medial KA UKA are needed.

Self-Aassembly of core-corona colloids under cylindrical confinement: A Monte Carlo study

Hierarchical self-assembly provides a versatile pathway for generating new functional materials. In this work, we show that confining core-corona colloids in a cylindrical cavity leads to an interesting repertoire of self-organized structures, some of which display hierarchical organization. Particle density, corona size, and cylinder radius were varied systematically to elucidate their role in colloidal arrangements. Extensive Monte Carlo simulations were performed to attain structural phase diagrams for the systems studied: complex mesophases are observed for certain model parameters. Among the observed morphologies are helical arrangements: simple and double helices consisting of particle stripes ordered around a cylindrical axis with a pitch dictated by the corona size. We also report the structural analysis of morphologies displaying stratified packing. Length scales of the core-corona particles and confining cylinders studied in this work are comparable to reported experimental systems. Our results offer practicable molecular design principles to obtain specific colloidal nanocrystalline arrangements for targeted applications.

Addressing the symmetry of a converging cylindrical shock wave in water close to implosion

We report experimental and numerical results relevant to the dynamics in the vicinity of the implosion axis of a strong shock wave generated by an underwater electrical explosion of a cylindrical array. Experiments were conducted using both sub-microsecond and microsecond timescale pulsed generators with stored energy up to ∼5 kJ, delivering ∼420/350 kA with a 320/1000 ns rise time pulses to the array, respectively. The backlighted images of the converging shock wave and the light emission around the cylindrical axis indicate strongly that the shock wave front keeps its azimuthal uniformity as far as r ≈30 μm. Also, images obtained almost simultaneously with the implosion suggest symmetric convergence &amp;lt;2 ns prior to the shockwave's arrival to the axis. In addition, the light emission obtained by a photo-multiplying tube suggests the existence of a ∼200 ns long, almost constant, strong afterglow immediately following the light emission peak related to the implosion.

Measured Resection Techniques Do Not Align to the Cylindrical Axis in Kinematic Total Knee Arthroplasty.

BackgroundThere has been increasing interest with improved functional results in kinematically aligned total knee arthroplasty. Kinematic alignment seeks to replicate the rotational axes of the individual knee. The femoral component can either be aligned to the estimated prearthritic distal and posterior joint lines via a measured-resection technique or by aligning to the cylindrical axis (CA). The CA is calculated using three-dimensional imaging and defined as a line equidistant from the medial and lateral condylar surfaces from 15° to 115° flexion. This study investigates whether these 2 techniques lead to similar alignment angles in the coronal plane.Materials and MethodsOne hundred three knees undergoing total knee arthroplasty were assessed using a computed tomography-based protocol. The image-based cylindrical axis coronal angle (CAA) was calculated, and the distal condylar coronal angle (DCA) was calculated to simulate a caliper measured resection technique. A computed tomographic planning software program was used to measure the offset from the distal-most extent of the calculated cylinder to the distal-most aspect of the condyles.ResultsThe DCA measured 3.3° valgus (standard deviation 2.4°) and the CAA 1.8° valgus (standard deviation 2.1°). The mean difference in offset from CAA radius to DCA from the medial condyle and the lateral condyle was 2.85 mm and 1.51 mm, respectively, increasing valgus predilection.ConclusionsCaliper measured resection kinematically aligned techniques will position the femoral component in a significantly more valgus position than when aligning to the CA of the knee. This is due to an increased offset of the distal femoral articulation from the most distal aspect of the cylinder on the medial side of the knee.

Cylindrical spikes

The Geroch/Stephani transformation is a solution-generating transformation, and may generate spiky solutions. The spikes in solutions generated so far are either early-time permanent spikes or transient spikes. We want to generate a solution with a late-time permanent spike. We achieve this by applying Stephani’s transformation with the rotational Killing vector field (KVF) of the locally rotationally symmetric Jacobs solution. The late-time permanent spike occurs along the cylindrical axis. Using a mixed KVF, the generated solution also features a rich variety of transient structures. We introduce a new technique to analyse these structures. Our findings lead us to discover a transient behaviour, which we call the overshoot transition. These discoveries compel us to revise the description of transient spikes.

A New \u201c\u03bb2\u201d Term for the Spalart\u2013Allmaras Turbulence Model, Active in Axisymmetric Flows

The new term belongs in the “basic,” free-shear-flow part of the Spalart–Allmaras (SA) model, and extends an idea of the Secundov team, incorporated in the νt-92 model. It detects transverse curvature in the distribution of the eddy viscosity tilde{nu } , so that it is passive in two-dimensional thin shear flows but potent especially in round jets. It eliminates the large over-prediction of the growth rate of such jets by the SA model, first detected by Birch in 1993. The originality is that the term is proportional to the middle eigenvalue λ2 of the Hessian operator of tilde{nu } . This is of course an empirical concept, but it is discriminating and rises when the distance r from the cylindrical axis becomes comparable with the length scale δ of the variations in the r direction. The inverted parabola is a prime example of such a distribution, and not unlike the tilde{nu } distribution in the round jet. The quantity λ2 is not infinitely differentiable, but it is free of singularities, and unlike the νt-92 version, is not dependent on two large quantities cancelling. The core term added to the Lagrangian derivative Dtilde{nu }/Dt is simply cb3 λ2 tilde{nu } , where cb3 is a new constant. The computing cost of calculating and ordering the eigenvalues is moderate. We have no proof of well-posedness for the new equation set, but the evidence so far is favorable, both in structured and unstructured grids. The λ2 term is calibrated on a fully-developed round jet, and tested in nine other cases, either 2D flows or flows in which r » δ, finding that in the latter it is negligible as expected. This is although the cb3 constant is rather large, namely 6. The λ2 term is not strong enough to make a mature vortex fully relaminarize as would be desirable, but the eddy viscosity drops by 74%. The raw λ2 term reduces the eddy viscosity in pipe flow, where that is detrimental; therefore, in the final model, it is multiplied by a function of the rSA parameter of the SA model, which is a measure of wall proximity. The λ2 term appears to be a safe addition to the SA model, and its application in different codes and to a variety of flows to be desirable.

Ion-temperature determination with a baffled Langmuir probe.

An electrostatic Langmuir probe for real-time measurements of parameters in magnetized plasma is tested in fully ionized, barium, Q-machine plasma. The small-diameter, long-length, tungsten wire sensor, i.e., the probe tip, oriented with its cylindrical axis perpendicular to the magnetic field (B), is partially shielded by ceramic baffles, or masks, that form sensor-access slots between the baffles. Adjusting the azimuthal orientation of the slots, by rotating the probe about its cylindrical axis, changes the fraction of proximity gyro-orbiting electrons, relative to the fraction of proximity gyro-orbiting ions, that can access the recessed sensor along the magnetic field. Thus, the ratio between the electron and ion saturation currents, Ie sat and Ii sat, can be adjusted without having affected the probe bias voltage Vb. When optimally shielded (Ie sat/Ii sat=1), accurate, real-time measurements of space potential Vs can be acquired. When maximally shielded (Ie sat/Ii sat≪1), accurate, real-time measurements of ion temperature Ti can be acquired. Subtracting the floating potential Vf of an optimally shielded baffled probe from Vf of a maximally shielded baffled probe yields Ti (and its fluctuation phase) in real time.

Magnetorheological elastomers — An underestimated class of soft actuator materials

In this paper, the results of various investigations on the viscoelastic and magnetic properties of magnetorheological elastomers (MRE) in magnetic fields of variable strength, are reported. These characteristics have a strong influence on the behavior of MRE in various applications such as vibration damping and tunable vibration absorbers. Moreover, the actuation capabilities of MRE with different kinds of deformation in a magnetic field are considered. The degree of deformation depends on the magnetic field strength and its gradient and can reach about 10%. When removing the magnetic field, the MRE body relaxes back to its initial shape. MRE materials can be used for linear actuators, where the MRE body is deformed due to the attraction by a magnetic circuit acting from one side. Such linear actuators may be applied for haptic feedback and pumps. However, ring-shaped MRE bodies can also deform radially around their cylindrical axis, if the magnetic field is oriented correspondingly. This unusual type of deformation allows the realization of a proportional valve, whose opening is controlled by the magnetic field strength. Similar configurations can be used for controllable seals, for locking devices and even for inchworm drives. Various versions of this actuation principle are discussed in the paper.