Rotational Motion Research Articles

Study of the stress-strain state in models of various options for osteosynthesis of tibial bones with diaphyseal fractures in the middle third in children with osteogenesis imperfecta and incomplete growth Part 1. Compression

Background. Osteogenesis imperfecta is accompanied by multiple fractures of skeletal bones, the development of progressive deformations of the long bones of the limbs and, as a result, the inability to stand and walk. At present, the most promising means for stabilizing bone fragments are intramedullary fixators of various designs. Installation of internal fixators without the possibility of their lengthening during the skeletal growth leads to an increase in the frequency of repeated surgical interventions due to the need for their replacement. The purpose was to investigate the stress-strain state of the lower leg models under the influence of compressive load in conditions of fracture of both bones in the middle third and their osteosynthesis using intramedullary rods of various designs in children with osteogenesis imperfecta and incomplete growth. Materials and methods. A mathematical modeling of osteosynthesis of tibial bones with a fracture in the middle third in children with osteogenesis imperfecta was performed in two options: 1 — using a rod without rotational stability; 2 — a rod with rotational stability of the structure. During the research, the stress-strain state of the model was studied under the influence of vertical compressive load. Results. Under compressive loads, the use of a rod with rotational stability does not lead to any significant changes in the stress-strain state of the model compared to tibial osteosynthesis with a rotationally unstable rod. This can be explained by the fact that before resisting the loads acting along the longitudinal axis of the rods, both rods are unstable, so all loads are carried by the bone structures. This is a “fee” for the opportunity to “grow”. The presence of rotational stability of an intramedullary rod does not have a significant effect on the stress distribution in the models under compressive loading. But it should be noted that when using a rotationally stable rod, the stresses in the distal tibia are slightly reduced, and what is especially important, in the fracture zone too. Thus, a growing rod with a locked rotational movement creates more favorable conditions for the fusion of tibial fractures in the middle third, which is of great importance in the treatment of children with osteogenesis imperfecta. Conclusions. Under the influence of compressive loads, the presence of rotational stability of an intramedullary rod does not provide significant advantages from the point of view of stress distribution in the model of a tibial fracture in the middle third. However, due to the presence of a movable support at the distal end of the tibia, even with a vertical compressive load, a small torque can occur between the bone fragments, which should block the rod with a locked rotational movement. This is the cause for a decrease in the stress in the distal fragment of the tibia.

INVESTIGATING THE EFFECT OF IRON PRESENCE IN THE MAGNETIC CIRCUIT OF A DOUBLE HELICAL WINDING INDUCTION MOTORS

The paper presented a new type of double helical-winding tubular induction motor (DHWTIM). The proposed motor consists of double- layer helical windings primary arranged on the same circumference with a common secondary. By controlling the phase sequence of supply voltage for each of primary winding layers, the secondary conductor would be capable of producing pure rotary motion, pure linear motion, or helical motion. An appropriate multi-layer analysis using cylindrical geometry is presented. This has been used to study the effect of iron presence in the magnetic circuit of the machine on its performance.

Assessment of the stiffness of the upper trapezius muscle in a group of asymptomatic people with cervical spine rotation asymmetry.

This study investigated the relationship between the stiffness of the upper trapezius muscle and the range of rotational movement of the cervical spine. A total of 60 right-handed asymptomatic students participated in the study. Participants (N = 22) characterised by asymmetry in rotational movements were selected for the experimental group. A difference of ≥10° between right and left rotation of the cervical spine was considered asymmetrical. The control group (N = 38) included participants whose rotation difference was < 10°. Belonging to the experimental or control group did not significantly differentiate trapezius muscle stiffness. The rotation side differentiated the stiffness of the right and left trapezius muscles only in the group of people with rotational movement asymmetry. There were high correlation coefficients between right cervical rotation and the stiffness of the muscle on the right side, and between rotation to the left and the stiffness of the muscle on the left side. There is a relationship between the stiffness of the right and left upper trapezius muscles and the range of right and left rotational motion of the cervical spine. Stiffness of the upper trapezius correlates more strongly with rotation to the side on which the muscle lies than to the opposite side. Increased stiffness of the upper trapezius muscle on the side of limited cervical spine rotation is likely to be determined by the muscle fibre stretching mechanism.

Nusselt and Sherwood correlations of multi-component hydrocarbon droplet in rotating natural convection

The study focused on examining the effect of rotation and high temperatures on the evaporation of multiple components of hydrocarbon droplets in natural convection. It analyzed the Nusselt and Sherwood correlations associated with this phenomenon. The study demonstrates consistent and reliable agreement in both the qualitative and quantitative aspects. The correlations consider rotational phenomenon and enhance the transfers in the vapor phase of mixtures containing multiple components (Heptane, Octane and Decane). They are developed considering the variability of thermophysical and transport properties, as well as the evaporation phenomenon and the heat and mass transfers of the rotating multicomponent hydrocarbon liquid droplet. For a frequency varying between 5 s−1 and 40 s−1, and an ambient temperature varied from 150 °C to 400 °C, the average Nusselt & Sherwood correlations are determined for Prandtl and Schmidt numbers varying between 0.7 < Pr < 0.97, and 1.58 < Sc < 3.13 respectively. The rise of the droplet rotational velocity indicates an augmentation that favors the prevalence of the convection phenomenon over conduction, and elucidating that vapor diffusion due to rotational motion surpasses the significance of the convection phenomenon. the enhancement of Nusselt and Sherwood correlations through the incorporation of rotational motion contributes to the improvement of the evaporation process for hydrocarbon droplets in combustion engines.

The wear and kinematics of two medially stabilised total knee replacement systems

BackgroundMedially stabilised total knee replacement systems aim to provide a more natural feeling knee replacement by providing increased stability through flexion. The aim of this study was to compare the kinematics and wear of two different medially stabilised total knee replacement systems in an experimental simulation study. The Medial Rotation Knee™ system (MRK) is an early medially stabilised knee (>20 years clinical success); the SAIPH® knee system being a more modern and refined, bone conserving evolution of the original design with a larger size range. MethodsThree SAIPH and three MRK total knee replacements (MatOrtho Ltd, UK) were investigated. The study was performed on a knee simulator with load controlled input kinematic conditions (ISO 14243–1). 6 million cycles of simulation were carried out with the wear of the UHMWPE tibial components assessed gravimetrically. The resulting anterior-posterior translation and tibial rotation position was measured throughout the study. ResultsThe mean UHMWPE wear rate was 0.57 ± 0.71 and 1.24 ± 2.0 mm3/million cycles for SAIPH and MRK total knee replacement systems respectively with no significant difference in wear (p = 0.24). Analysis of simulator output kinematics showed a larger range of anterior-posterior motion for SAIPH total knee replacements compared to MRK. The magnitude of tibial rotation was low for both knee replacement systems. ConclusionThe small magnitude of anterior-posterior displacement and tibial rotation motion demonstrates the inherent stability of this knee system design offered by the constrained medial compartment. This study shows the potential for medially stabilised knee systems as a low polyethylene surface wear solution.

Hybrid cortical bone trajectory and modified cortical bone trajectory techniques in transforaminal lumbar interbody fusion at L4-L5 segment: A finite element analysis

BackgroundThe academia has increasingly acknowledged the superior biomechanical performance of the hybrid fixation technique in recent years. However, there is a lack of research on the hybrid fixation technique using BCS (Bilateral Cortical Screws) and BMCS (Bilateral Modified Cortical Screws). This study aims to investigate the biomechanical performance of the BCS and BMCS hybrid fixation technique in transforaminal lumbar interbody fusion (TLIF) at the L4-L5 segment in a complete lumbar-sacral finite element model. MethodsThree cadaver specimens are used to construct three lumbar-sacral finite element models. The biomechanical properties of various fixation technologies (BCS-BCS, BMCS-BMCS, BMCS-BCS, and BCS-BMCS) are evaluated at the L4-5 segment with a TLIF procedure conducted, including the range of motion (ROM) of the L4-5 segment, as well as the stress experienced by the cage, screws, and rods. The testing is conducted under specific loading conditions, including a compressive load of 400 N and a torque of 7.5Nm, subjecting the model to simulate flexion, extension, lateral bending, and rotation. ResultsNo significant variations are seen in the ROM at the L4-5 segment when comparing the four fixation procedures during flexion and extension. However, when it comes to lateral bending and rotation, the ROM is ordered in descending order as BCS-BCS, BCS-BMCS, BMCS-BMCS, and BMCS-BCS. The maximum stress experienced by the cage is observed to be highest within the BMCS-BCS technique during movements including flexion, extension, and lateral bending. Conversely, the BMCS-BMCS technique exhibits the highest cage stress levels during rotational movements. The stress applies to the screws and rods order the sequence of BCS-BCS, BCS-BMCS, BMCS-BCS, and BMCS-BMCS throughout all four working conditions. ConclusionThe BMCS-BCS technique shows better biomechanical performance with less ROM and lower stress on the internal fixation system compared to other fixation techniques. BMCS-BMCS technology has similar mechanical performance to BMCS-BCS but has more contact area between screws and cortical bone, making it better for patients with severe osteoporosis.

Development of a Position Control System for Wheeled Humanoid Robot Movement Using the Swerve Drive Method Based on Fuzzy Logic Type-2

A humanoid robot is capable of mimicking human movements, which poses a challenge for researchers. This has led some to utilise wheels to facilitate its motion. However, achieving smooth and accurate movements at desired positions remains a challenge, necessitating the development of an optimal control system and movement method. In this study, solutions to address these challenges include the use of type-2 fuzzy logic controller (FLC) and the swerve drive method. During the steering rotation movement testing, type-1 FLC exhibits the fastest response time of 0.8 seconds, but oscillations occur, reaching up to 117 degrees to achieve the set point of 90 degrees. Additionally, type-1 FLC cannot reach the set point of -90 degrees. On the contrary, type-2 FLC aligns successfully with both set points of 90 and -90 degrees. In coordinate movement testing, type-1 FLC still shows an error between 1 cm and 2 cm compared to type-2 FLC, particularly with 3 and 5 members, which are equal to the given set point. The results of the tests indicate that type-2 FLC is reliable, showing a small steady-state error, stability, and no overshoot, despite its longer response time and processing duration compared to type-1 FLC.

Rotational nonlinear energy harvesting via an orthogonal dual-beam

Various nonlinear energy harvesters that harvest energy from rotational motion have been investigated, but their performance at low frequencies is always deficiency. To realize the efficient harvesting of low frequency rotational motion energy, rotational nonlinear energy harvesting via an orthogonally arranged dual-beam is proposed for the first time. Based on the energy method, the electromechanical coupling equation of orthogonally arranged dual-beam in rotating motion is derived in detail. The harmonic balance method together with arc length continuation is employed to approximate the frequency response functions of the output power. To deeply explore the nonlinear dynamic behavior of the system, numerical analysis is conducted to obtain the output voltage and phase diagram in the time domain. Finally, the theoretical analysis results are verified through experiments. The results demonstrate that the vertical arrangement of nonlinear dual-beam in rotational motion effectively improved the energy harvesting efficiency at low frequencies, with excellent energy harvesting performance. This study provides an effective technical approach to energy harvesting for low frequency rotating systems.

Synthesis and Dynamic Behavior of Ce(IV) Double-Decker Complexes of Sterically Hindered Phthalocyanines.

Phthalocyanines and their double-decker complexes are interesting in designing rotative molecular machines, which are crucial for the development of molecular motors and gears. This study explores the design and synthesis of three bulky phthalocyanine ligands functionalized at the α-positions with phenothiazine or carbazole fragments, aiming to investigate dynamic rotational motions in these sterically hindered molecular complexes. Homoleptic and heteroleptic double-decker complexes were synthesized through the complexation of these ligands with Ce(IV). Notably, CeIV(Pc2)2 and CeIV(Pc3)2, both homoleptic complexes, exhibited blocked rotational motions even at high temperatures. The heteroleptic CeIV(Pc)(Pc3) complex, designed to lower symmetry, demonstrated switchable rotation along the pseudo-C4 symmetry axis upon heating the solution. Variable-temperature 1H-NMR studies revealed distinct dynamic behaviors in these complexes. This study provides insights into the rotational dynamics of sterically hindered double-decker complexes, paving the way for their use in the field of rotative molecular machines.

Design and Construction of a Prototype of an Assisting Device for Arm Exercise

A new portable arm exercise device is presented as a laboratory prototype to assist arm movements in rehabilitation therapies and movement exercises. Unlike the devices currently used, a portable design is proposed, with easy assembly and operational characteristics that enable it to be used by users in the home and in a familiar environment. Sensors are also provided on the rotating crank to validate and monitor the efficiency of the arm exercise. A low-cost prototype is assembled using off-the-shelf components and 3D-printed parts. Design issues are discussed and elaborated on to build a prototype for future laboratory testing using fairly simple experimental methodology. Preliminary testing by one author shows good feasibility of the device. The findings from the experimental results can be summarized as effective smooth-monitored cyclic motion in the crank rotation with limited values for acceleration less than 1 g and for acting user forces less than 22 N. The values detected are significantly lower in the left hand, with the testing subject being right-handed and healthy, without injury to her upper limbs.

Improving image quality using the pause function combination to PROPELLER sequence in brain MRI: a phantom study.

While some MRI systems offer a "pause" function, combining it with the PROPELLER method for image quality improvement remains underexplored. This study investigated whether repositioning the head after pausing during PROPELLER imaging enhances image quality. All brain phantom images in this study were obtained using a 3.0T MRI and acquired using the fast spin-echo T2WI-based PROPELLER with motion correction. By combining the angle of rotational motion of the head phantom and the number of repositioning after a pause, two studies including seven trials were performed. Increasing the rotation angle decreased the image quality; however, pausing the image and repositioning the head phantom to the original angle improved the image quality. A similar result was obtained by repositioning the angle closer to its original angle. Experiments with multiple head movements showed that pausing the scan and repositioning the phantom with each movement improved image quality.

Rising and settling 2-D cylinders with centre-of-mass offset

Rotational effects are commonly neglected when considering the dynamics of freely rising or settling isotropic particles. Here, we demonstrate that particle rotations play an important role for rising as well as for settling cylinders in situations when mass eccentricity, and thereby a new pendulum time scale, is introduced to the system. We employ two-dimensional simulations to study the motion of a single cylinder in a quiescent unbounded incompressible Newtonian fluid. This allows us to vary the Galileo number, density ratio, relative moment of inertia (MOI) and centre-of-mass (COM) offset systematically and beyond what is feasible experimentally. For certain buoyant density ratios, the particle dynamics exhibits a resonance mode, during which the coupling via the Magnus lift force causes a positive feedback between translational and rotational motions. This mode results in vastly different trajectories with significantly larger rotational and translational amplitudes and an increase of the drag coefficient easily exceeding a factor two. We propose a simple model that captures how the occurrence of the COM offset induced resonance regime varies, depending on the other input parameters, specifically the density ratio, the Galileo number and the relative MOI. Remarkably, depending on the input parameters, resonance can be observed for COM offsets as small as a few per cent of the particle diameter, showing that the particle dynamics can be highly sensitive to this parameter.

Investigation of tribological properties of hydrothermally synthesized halloysite composites with carbon, MoS2 and CuO

To enhance the antiwear properties of halloysite nanotubes (HNTs), composites of C/HNTs, CuO/HNTs, and MoS2/HNTs were prepared using hydrothermal method, and their tribological properties were investigated. The results indicated that the wear resistance was ranked as follows during rotational motion: PAO10 oil < CuO/HNTs (9.1%) < MoS2/HNTs (34.5%) < HNTs (41.8%) < C/HNTs (56.4%). In reciprocal motion, the antiwear performance was ordered as follows: PAO10 oil < HNTs < MoS2/HNTs < CuO/HNTs < C/HNTs. The consistently superior antiwear performance of C/HNTs can be attributed to the synergistic effect of carbon transfer with HNTs, which rapidly generate a homogeneous carbon film embedded in Fe2O3, Fe3O4 and SiOx. In contrast, MoS2 and CuO exhibited inhibitory and competitive effects on the film formation of HNTs.

Dynamics of activation in the voltage-sensing domain of Ciona intestinalis phosphatase Ci-VSP

The Ciona intestinalis voltage-sensing phosphatase (Ci-VSP) is a membrane protein containing a voltage-sensing domain (VSD) that is homologous to VSDs from voltage-gated ion channels responsible for cellular excitability. Previously published crystal structures of Ci-VSD in putative resting and active conformations suggested a helical-screw voltage sensing mechanism in which the S4 helix translocates and rotates to enable exchange of salt-bridge partners, but the microscopic details of the transition between the resting and active conformations remained unknown. Here, by combining extensive molecular dynamics simulations with a recently developed computational framework based on dynamical operators, we elucidate the microscopic mechanism of the resting-active transition at physiological membrane potential. Sparse regression reveals a small set of coordinates that distinguish intermediates that are hidden from electrophysiological measurements. The intermediates arise from a noncanonical helical-screw mechanism in which translocation, rotation, and side-chain movement of the S4 helix are only loosely coupled. These results provide insights into existing experimental and computational findings on voltage sensing and suggest ways of further probing its mechanism.

Upper Extremity Musculoskeletal Profiles in Tennis Players: A Systematic Review.

Tennis-specific musculoskeletal (MSK) screening can assess range of motion (ROM) and muscular imbalances. Identifying normative values before implementing a MSK screen is essential in contributing to athlete performance and injury risk profiles. To review upper extremity MSK data in healthy tennis players across age, sex, and level of play. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed for this review. A search was conducted in MEDLINE, SPORTDiscus, Embase, and CINAHL. This review included shoulder, elbow, and wrist ROM, isometric strength, or isokinetic strength in a tennis population. Each article was critically appraised to help identify the internal and external validity of each study. Systematic review. Level 3. A total of 41 studies met the search criteria. Each contributor organized the data elements of interest into data tables, with a second contributor assigned for review. Data elements of interest included player and study characteristics: ROM, isometric dynamometry, and isokinetic strength. A total of 3174 players were included in the final studies. Most of the players included were competitive adolescents and young adults; 15 studies included ROM data. Male tennis players consistently had more external rotation (ER) gain (range, 1.8º to 8.8º) and internal rotation (IR) loss (range, -15.3º to -3.0º) when compared with their female counterparts (ER range, -2.5º to 5.8º; IR range, -10.4º to -3º). Shoulder IR and ER strength were measured in the majority of all the strength studies, with the external rotators generating at least two-thirds the strength of the internal rotators. Overall MSK data of tennis players indicate that shoulder strength values are often larger than nontennis players, but equal to or slightly lower than comparable athletes in other overhead sports. Adaptive changes of the glenohumeral joint and subsequent rotational motion are similar to those of other overhead athletes.

Seismic improvement of structures using hybrid self-centring dampers and rocking core

Extensive research on seismic-resistant systems aims to lower earthquake repair costs and downtime. This article presents a novel low-damage self-centring system that aims to improve the seismic resilience of buildings by enabling controlled rocking motion while reducing the risk of overturning. Significantly, the rotational movement can be entirely restored. This system combines a rocking core with damping devices, including disc springs and peripheral slit dampers. In this hybrid system, two damping devices are mounted to both first-floor columns of the rocking bays and the rigid movement of the rocking core triggers the dampers. Firstly, a comparative investigation was conducted to assess the efficacy of the endorsed hybrid system. The cyclic pushover results showed that the hybrid system is superior to other typical bracing systems in energy dissipation, with a five times higher margin. In addition, by employing the suggested system, the frame's drift ratio profile under nonlinear time history analysis (NTH) remained consistent throughout the structure, indicating its ability to withstand the soft storey mechanism. Secondly, a comprehensive assessment was conducted on the proposed system's collapse using incremental dynamic analysis (IDA) took into account various seismic intensities and engineering demand parameters for buildings with different bay lengths and included low, medium, and high-rise structures. The system's flag-shaped behavior and self-centring capability were confirmed by the average residual drift ratio of approximately 0.03% (almost zero) for all examined structures. Also, the collapse performance of the system exhibited a safety margin against collapse, with an average of 1.9 across all buildings and seismic intensities.

Clustering, rotation, and swirl of inertial particles in turbulent channel flow

Clustering dynamics of inertial particles in turbulent channel flow are studied via tessellation-based analysis of high-fidelity simulation data at Reτ≈230 with various values of mass loading (10%−100%) and the Stokes number (St+=[1−60]). We then characterise the solenoidal, rotational, and swirling motions of clusters by computing the probability density functions (PDFs) of the divergence, curl, and helicity of the particle velocity, as well as their dependence on wall-normal distance, using the methods of Oujia et al. (2020); Maurel–Oujia et al. (2023). Particle inertia gives heavier tails to the PDFs of divergence and curl, suggesting enhanced intermittency in the convergence/divergence of clusters, and in their rotational motions. The fluctuations of the divergence and curl are most intense in the buffer layer, due to the stronger fluctuations of fluid velocity there. Similarities are identified between the cluster dynamics in the logarithmic region and those in homogeneous isotropic turbulence, including the dependence of divergence, curl, and helicity on Stokes number. The effect of increasing mass loading on cluster dynamics is relatively small except in the viscous sublayer, where attenuation of clustering, rotation, and swirling motions are observed. The effect of increasing Stokes number on the viscous sublayer is different, resulting in more intense convergence/divergence and rotation of particle clusters, as the particles become more independent of the carrier fluid.

Enhancing Precision: A Visual Guide to Drill-Assisted External Dacryocystorhinostomy Surgery.

This technical report aims to provide a visual guide to the drill-assisted external dacryocystorhinostomy (DCR) technique with silicone intubation. Through a step-by-step video demonstration, it addresses inherent documentation challenges and highlights crucial considerations. A critical aspect of the procedure's success lies in creating a clear space around the drilling area to prevent thermal burns and soft tissue wrapping around the burr. Additionally, it emphasizes the careful use of smaller burr diameters and the importance of drilling techniques, advocating for minimal perpendicular drilling while maintaining rotational polishing movements to minimize the risk of rapid penetration and potential nasal mucosal injury. The thermal cauterization of perforating nutrient vessels during bone drilling offers a significant advantage in reducing the risk of bleeding. A review of existing limited studies comparing drill-assisted and conventional external DCR reveals advantages such as shorter surgical duration, lower intraoperative hemorrhage rate, more regular osteotomy edges, increased ostomy patency, and potential prevention of soft tissue or mucosal injuries. Nonetheless, achieving these benefits necessitates enhanced hand and foot coordination. However, despite these benefits, a noticeable gap exists in the literature concerning comprehensive studies and comparative analyses. Furthermore, exploring the associated cost and learning curve of adopting this surgical technique is essential. This report aims to fill the existing gap in the literature and serve as a visual reference for surgeons interested in adopting drill-assisted external DCR.

Coupled Rotary Motion in Molecular Motors.

Biological molecular machines play a pivotal role in sustaining life by producing a controlled and directional motion. Artificial molecular machines aim to mimic this motion, to exploit and tune the nanoscale produced motion to power dynamic molecular systems. The precise control, transfer, and amplification of the molecular-level motion is crucial to harness the potential of synthetic molecular motors. It is intriguing to establish how directional motor rotation can be utilized to drive secondary motions in other subunits of a multicomponent molecular machine. The challenge to design sophisticated synthetic machines involving multiple motorized elements presents fascinating opportunities for achieving unprecedented functions, but these remain almost unexplored due to their extremely intricate behavior. Here we show intrinsic coupled rotary motion in light-driven overcrowded-alkene based molecular motors. Thus far, molecular motors with two rotors have been understood to undergo independent rotation of each subunit. The new bridged-isoindigo motor design revealed an additional dimension to the motor's unidirectional operation mechanism where communication between the rotors occurs. An unprecedented double metastable state intermediate bridges the rotation cycles of the two rotor subunits. Our findings demonstrate how neighboring motorized subunits can affect each other and thereby drastically change the motor's functioning. Controlling the embedded entanglement of active intramolecular components sets the stage for more advanced artificial molecular machines.

Global rotation of skyrmion bags under vertical microwave fields

Magnetic skyrmion bags are composite topological spin textures with arbitrary topological charges. Here, we computationally study the transient rotational motion of skyrmion bags, which is characterized by a global rotation of inner skyrmions around the central point. Distinct from conventional rotational modes found in skyrmions, the observed rotation is a forced motion associated with the breathing mode induced solely by vertical microwave fields. The driving force behind this rotation originates from the interactions between outer and inner skyrmions, with the angular velocity determined by the phase difference resulting from their asynchronous breathing behaviors. It is also found that skyrmion bags with larger skyrmion numbers are more conducive to the occurrence of the rotation. Our results are useful for understanding the cluster dynamics of complex topological spin textures driven by dynamic fields.