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City traffic conditions contain frequent starts and stops. Thus, Single-Stage Continuously Variable Transmissions are subject to high loads when operating at high gear ratios, leading to excessive friction that cause slipping and heating of friction elements. This study proposes a microprofile with undulation on the surface of the pulley. A mathematical dependence on the technological quality assurance of the surface layer of the V-belt transmission parts formed during turning is proposed, enabling the prediction of height parameters of undulation depending on the change in the spindle speed, feed, and cutting speed. Estimating the error in the field experiment data and calculating values of the proposed methodology showed that the height parameters of the undulation of pulleys have a relative error of 6.3%. [ABSTRACT FROM AUTHOR]

City traffic conditions contain frequent starts and stops. Thus, Single-Stage Continuously Variable Transmissions are subject to high loads when operating at high gear ratios, leading to excessive friction that cause slipping and heating of friction elements. This study proposes a microprofile with undulation on the surface of the pulley. A mathematical dependence on the technological quality assurance of the surface layer of the V-belt transmission parts formed during turning is proposed, enabling the prediction of height parameters of undulation depending on the change in the spindle speed, feed, and cutting speed. Estimating the error in the field experiment data and calculating values of the proposed methodology showed that the height parameters of the undulation of pulleys have a relative error of 6.3%.

The development and evaluation of a mild steel permanent mould were conducted with considerations based on materials availability, cost efficiency, and national economic development. The design, material selection, and fabrication strategy were all carefully chosen to meet these objectives. Geometric modelling of the mould design was carried out using Pro/Engineer® software, generating various views and parameters of the mould with and without components. Mild steel was chosen for mould production due to its strength, rigidity, availability, high melting temperature, surface finish, and machinability. Fabrication of the mould utilized basic machine tools such as a lathe machine and drilling machine. To evaluate the performance of the developed mould, an aluminium alloy pulley was produced using the mould and aluminium scraps. Microstructural analysis and hardness tests were performed on mould samples before and after casting. The results indicate that the heated mould sample, after casting, exhibits a fine-induced dendritic structure comprised of smaller grains, whereas the microstructure of the unheated mould displayed larger grain sizes. The maximum hardness number recorded was 204 HV for the mould sample after casting, indicating the ability of the mould material to withstand fatigue stresses and wear generated during casting.

The flexor tendon pulleys in the fingers of the hand are fibrous structures of variable size, shape, and thickness that cover the synovial sheath of these tendons. Despite their clinical relevance, their arrangement and configuration in each of the triphalangeal fingers have been little studied and with small sample sizes. 192 triphalangeal fingers belonging to 48 fresh body donors' hands were dissected. Multivariate analysis was carried out. Twenty‐five cases (52%) were left hands, and 26 of the 48 hands belonged to female donors (54.2%). The results were analyzed by fingers for each of the 5 annular pulleys, the 3 cruciform pulleys and the gaps between them. In addition, the most and least frequent configurations of the pulleys in each of the fingers were studied, observing that the classic pattern with all the pulleys appeared only in 3 fingers (1.56%), while the most frequent pattern was A1‐A2‐C1‐A3‐A4, which was seen in 35 fingers (18.22%). Conclusions: The flexor pulleys in the triphalangeal fingers of the hand have shown enormous variability in arrangement and shape, and also rarely appear all in the same finger. This peculiar anatomical arrangement can help the different professionals who perform their clinical work in this region. [ABSTRACT FROM AUTHOR]

Ruptures of the annular pulleys of the finger flexor tendons are not common in the general population. In sport climbing, these structures can be abnormally stressed, mainly because of the so-called crimped position, an extreme flexion of the proximal interphalangeal joint, levering an abnormal tension by flexor tendons. Complete pulley tears manifest with explicit pain and an inability, but strains or minor tears might only be perceived by individuals like professional climbers, since they can bring total disability to crucial grip positions. Complete tears of one or more pulleys have already been characterized by ultrasound and magnetic resonance, but no imaging features were described for strains or smaller partial tears. We describe the case of a climber with symptoms of an A2-pulley injury, in whom ultrasound imaging revealed reversible features of fusiform thickening and hypoechogenicity, which resemble the strains that we find in similar structures like tendons and other ligaments. [ABSTRACT FROM AUTHOR]

Progressive esotropia accompanied by restricted abduction and supraduction due to high myopia is known as esotropia fixus with high myopia or heavy eye syndrome (HES). Some conditions, such as sagging eye syndrome (SES), show esotropia for distance or cyclovertical strabismus with no abduction limitations despite highly myopic eyes. We evaluated the magnetic resonance imaging (MRI) findings and clinical features of HES, high myopia with SES-like symptoms (highly myopic SES), and SES. We reviewed all patients diagnosed with HES, highly myopic SES, and SES who underwent MRI of the orbits and brain over 6 years. To quantitatively assess the orbital anatomy, we compared the conditions of the superior rectus muscle (SR), lateral rectus muscle (LR), and inferior rectus muscle (IR) using orbital MRI among the three groups. Among the 14 patients (27 eyes) with high myopia, 5 (9 eyes) had HES, and 9 (18 eyes) had highly myopic SES. Eleven patients (22 eyes) with SES were also compared with these 14 patients. The mean axial length was 29.6 ± 1.0 mm in participants with HES, 29.0 ± 1.5 mm in those with HES-SES, and 23.7 ± 0.9 mm in those with SES. The average distance esotropia was 48.0 ± 19.9Δprism, 4.6 ± 1.5Δprism, and 6.1 ± 4.6Δprism for participants with HES, highly myopic SES and SES, respectively. The average distance hypertropia was 5.3 ± 5.9Δprism in participants with highly myopic SES and 4.8 ± 2.7Δprism in those with SES. The mean vertical angle of the LR was 32.6 ± 10.8°, 18.1 ± 5.4°, and 14.6 ± 6.8°; the mean tilting angle of the LR was 31.6 ± 9.2°, 15.9 ± 6.0°, and 13.8 ± 5.9°; and the mean displacement angle between the LR and SR was 152.3 ± 16.7°, 125.0 ± 7.1°, and 112.5 ± 7.5° for participants with HES, highly myopic SES and SES, respectively. The LR-SR displacement angle in HES-SES was significantly larger than in SES (p <.001) but the vertical and tilting angles were not. Also, the IR shift showed no significant difference with HES-SES and HES (5.8 ± 1.4 mm and 5.3 ± 1.2 mm) but not with SES (4.0 ± 0.8 mm) (p <.0001). SES-like symptoms can develop in highly myopic eyes; however, MRI showed that the state of the LR muscle in highly myopic SES deviated almost similarly to that in SES; however, the eyeball was more dislocated than in SES. This may be useful in deciding the appropriate operative procedure. [ABSTRACT FROM AUTHOR]

Wheelchairs are widely used globally and are essential for providing autonomy and mobility to elderly and disabled people who have movement restrictions. Manual wheelchairs require operation through turning the wheels or pushing the wheelchair directly, thus posing mobility limitations for the user and caregiver. In contrast, electric wheelchairs, when used by the user, allow for improved flexibility by operating the wheelchair through a single control mechanism. However, the use of electric wheelchairs poses challenges in accessing areas with stairs and curbs, limiting the range of activity and thereby diminishing the quality of life for users and those reliant on electric wheelchairs. The electric wheelchair developed in this research incorporates a single motor for lightweight design. It uses a wheel travel variation actuator, eliminating the need for synchronization and allowing for low-power operation. This design reduces power loss from the caterpillar's idling during wheel movement and includes the implementation of a pulley system. The optimal pulley belt length was calculated, and a deceleration device was installed inside the caterpillar, enabling a design that is compact, lightweight, and capable of high deceleration. On paved roads and flat terrain, the electric wheelchair is designed for high-speed travel using two pairs of front omni wheels and drive wheels. For terrains with stairs, speed bumps, unpaved roads, and unavoidable obstacles, the wheelchair is powered by caterpillars. The electric wheelchair developed through the research presented in this paper has verified the reliability of its transmission system through gear stress and deformation analysis. Additionally, an electric wheelchair based on the proposed concept was constructed to validate the drivability, safety, operability, and convenience of its driving unit. Furthermore, a user rode the constructed electric wheelchair to confirm that there were no issues with its drivability. [ABSTRACT FROM AUTHOR]

Introduction: Dorsal fracture dislocations (DFD) of the proximal interphalangeal joint (PIPJ) are challenging fractures. A palmar surgical approach and plate fixation has a high complication rate, including flexor contractions, reduction of range of motion (ROM) and secondary need for plate removal. Methods: We use the flexor tendon pulleys to cover the mini plate with the assumption that it may reduce the adhesion between the mini plates and the tendons and reduce postoperative complications. We present the outcomes of using this technique in eight patients. Results: All patients had an excellent outcome at a mean follow-up of 17 months, and none required removal of the implants. Conclusions: This study presents a surgical technique that may potentially reduce the high complication rate found after ORIF for treatment of DFD of the PIPJ. Therefore, improving the clinical outcomes after this type of surgery. Level of Evidence: Level IV (Therapeutic) [ABSTRACT FROM AUTHOR]

Transmission on the vehicle is very important component to ensure maximum power transfer from the engine to the wheels. The speed of four-wheeled vehicles is influenced by the transmission system used. Pulley is the component of continuous variable transmission (CVT) which is currently widely used in the automotive industry. The CVT transmission is type of automatic transmission with gearshift process that does not use gears, but uses pulley. The pulley is made of stainless steel. For CVT transmission there are two pulleys, both of which are called driven pulleys. The CVT transmission shift operation is controlled electronically from the computer to drive the two pulleys. These two pulleys can move to the right or to the left, respectively, so that the width of the two pulleys can change to narrow or widen. The drive pulley moves away so the belt will move inward and the same time the driven pulley will narrow so the belt will move further out. The pulley diameter becomes the gear ratio in a CVT transmission. In the CVT transmission process there will be friction between the two surfaces of the pulley and the belt, therefore it is necessary to measure the hardness of the material from the pulley to ensure the vehicle's transmission capability. In this study, the hardness of the pulley material was measured using a Vickers machine according to the ASTM 6507 standard with a given load of 0.3 kg. The measurement results obtained an average value of hardness Vickers (HV) for the pulley material of 473.

Abstract In order to improve the elderly people’s quality of life, supporting their walking behaviors is a promising technology. Therefore, based on one ultrasonic motor, a wire-driven series elastic mechanism for walking assistive system is proposed and investigated in this research. In contrast to tradition, it innovatively utilizes an ultrasonic motor and a wire-driven series elastic mechanism to achieve superior system performances in aspects of simple structure, high torque/weight ratio, quiet operation, quick response, favorable electromagnetic compatibility, strong shock resistance, better safety, and accurately stable force control. The proposed device is mainly composed of an ultrasonic motor, a linear spring, a steel wire, four pulleys and one rotating part. To overcome the ultrasonic motor’s insufficient output torque, a steel wire and pulleys are smartly combined to directly magnify the torque instead of using a conventional gear reducer. Among the pulleys, there is one tailored pulley playing an important role to keep the reduction ratio as 4.5 constantly. Meanwhile, the prototype is manufactured and its actual performance is verified by experimental results. In a one-second operating cycle, it only takes 86 ms for this mechanism to output an assistive torque of 1.6 N·m. At this torque, the ultrasonic motor’s speed is around 4.1 rad/s. Moreover, experiments with different operation periods have been conducted for different application scenarios. This study provides a useful idea for the application of ultrasonic motor in walking assistance system.

Purpose. The main purpose of our work is to substantiate the geometric parameters of a variable moment of inertia pulley, which can reduce the weight of a drive with such a pulley. Methodology. It was found that the masses of the pulley and support elements have the greatest influence on the weight of the drive, so we focused on the pulley. Improvement of the pulley design and determination of its rational geometric parameters were carried out in three stages. At the first stage, the size of the rim was reduced in accordance with the diameter of the rope. At the second stage, a multivariate calculation was performed for a pulley with spokes that expand toward the rim. Holes were made in the spokes to reduce the pulley weight. The fundamental difference of the pulley calculated at the third stage is the absence of holes in the spokes, which makes it possible to increase the rigidity of the structure. The control parameter was the angle of expansion of the spokes. The problem of establishing a rational value for this angle was solved using the SolidWorks computer program with the Simulation application, subject to the constraints on the safety factor (at least two) and the structural rigidity parameters (displacement along three coordinate axes and the resulting displacement at the level of the values for the base structure). Findings. It has been established that the weight optimization of a drive with a variable moment of inertia pulley is advisable to be carried out by reducing the masses of the pulley and supporting elements. The best design is that of a variable moment of inertia pulley that contains spokes (without holes) that expand toward the rim; the rational angle of expansion of the spokes is 25°. If a pulley with reasonable geometric parameters is used, the mass of the drive will decrease by 16% in the case of a 33 % reduction in the mass of the pulley itself compared to the mass of the basic design. Originality. A new design is proposed and rational parameters of the variable moment of inertia pulley are substantiated, which make it possible to reduce the mass of the drive with such a pulley. Practical value. The use of the pulley of this design will reduce the load on the electric motor during startup, as well as the load on the supporting structures.

Background. Modern requirements for passenger cars include a number of main directions: efficient use of energy, improvement of environmental indicators, improvement of operational characteristics. The use of variator gearboxes has significantly improved the energy efficiency and environmental performance of the car due to optimal engine performance. However, the disadvantage of variators in comparison with manual transmissions is still insufficient efficiency, which does not allow competing with “mechanics” due to low performance characteristics. Since the variator is a friction mechanism, a way to increase the efficiency of its operation is to change the coefficient of friction in friction pairs. One of the options for such modernization is the creation of a regular microprofile on the surface of friction pulleys, namely– undulations. The actual contact spots formed by the undulation provide sufficient traction of the variator transmission and minimize power loss. The object of the study is the relationship between power indicators and the quality of the surface layer of friction elements of a continuously variable transmission. The subject of the study is an adequate assessment and provision of the power parameters of a continuously variable transmission, by ensuring the surface quality parameters of the drive pulley of the variator. The purpose of the study is to develop a technique for providing power indicators of a variator transmission by creating a wavy microprofile based on the mechanics of contact interaction. Materials and methods. The theoretical and experimental research carried out in the work is based on the study of literature, conducted research and the experience of practicing technologists. Results. The empirical dependence of the prediction of the coefficient of friction at normal wear depending on the parameters of surface quality is analyzed. It is shown that the parameters of the undulation of the surface have a greater influence on the coefficient of friction, and as a consequence, the traction ability of the transmission in the frictional interaction of parts, than the roughness parameters. Analytical dependences of determining the power on the output shaft of the variator and the efficiency of the variator depending on the height parameter of the waviness are proposed. Conclusions. Based on the conducted research and experiments, a mathematical model is proposed to ensure the power parameters of variators by forming a high-altitude waviness index. This will make it possible to predict and ensure the coefficient of friction of the friction pair at the stage of development work and drawing up the technological process of processing parts.

Wheelchairs are widely used globally and are essential for providing autonomy and mobility to elderly and disabled people who have movement restrictions. Manual wheelchairs require operation through turning the wheels or pushing the wheelchair directly, thus posing mobility limitations for the user and caregiver. In contrast, electric wheelchairs, when used by the user, allow for improved flexibility by operating the wheelchair through a single control mechanism. However, the use of electric wheelchairs poses challenges in accessing areas with stairs and curbs, limiting the range of activity and thereby diminishing the quality of life for users and those reliant on electric wheelchairs. The electric wheelchair developed in this research incorporates a single motor for lightweight design. It uses a wheel travel variation actuator, eliminating the need for synchronization and allowing for low-power operation. This design reduces power loss from the caterpillar’s idling during wheel movement and includes the implementation of a pulley system. The optimal pulley belt length was calculated, and a deceleration device was installed inside the caterpillar, enabling a design that is compact, lightweight, and capable of high deceleration. On paved roads and flat terrain, the electric wheelchair is designed for high-speed travel using two pairs of front omni wheels and drive wheels. For terrains with stairs, speed bumps, unpaved roads, and unavoidable obstacles, the wheelchair is powered by caterpillars. The electric wheelchair developed through the research presented in this paper has verified the reliability of its transmission system through gear stress and deformation analysis. Additionally, an electric wheelchair based on the proposed concept was constructed to validate the drivability, safety, operability, and convenience of its driving unit. Furthermore, a user rode the constructed electric wheelchair to confirm that there were no issues with its drivability.

In order to improve the elderly people's quality of life, supporting their walking behaviors is a promising technology. Therefore, based on one ultrasonic motor, a wire-driven series elastic mechanism for walking assistive system is proposed and investigated in this research. In contrast to tradition, it innovatively utilizes an ultrasonic motor and a wire-driven series elastic mechanism to achieve superior system performances in aspects of simple structure, high torque/weight ratio, quiet operation, quick response, favorable electromagnetic compatibility, strong shock resistance, better safety, and accurately stable force control. The proposed device is mainly composed of an ultrasonic motor, a linear spring, a steel wire, four pulleys and one rotating part. To overcome the ultrasonic motor's insufficient output torque, a steel wire and pulleys are smartly combined to directly magnify the torque instead of using a conventional gear reducer. Among the pulleys, there is one tailored pulley playing an important role to keep the reduction ratio as 4.5 constantly. Meanwhile, the prototype is manufactured and its actual performance is verified by experimental results. In a one-second operating cycle, it only takes 86 ms for this mechanism to output an assistive torque of 1.6 N·m. At this torque, the ultrasonic motor's speed is around 4.1 rad/s. Moreover, experiments with different operation periods have been conducted for different application scenarios. This study provides a useful idea for the application of ultrasonic motor in walking assistance system. [ABSTRACT FROM AUTHOR]

Background: The palmar aponeurosis or "A0 pulley" may play a role in trigger finger pathology. This study assesses the involvement of the A0 pulley in patients receiving trigger finger release. Methods: This single-surgeon, prospective, randomized clinical trial was conducted among consenting patients with symptomatic trigger finger. Intraoperative coin toss was used to randomize initial release of either the A0 or A1 pulley. Following release, active flexion and extension of the affected digit were examined. The remaining pulley was then released in sequence, and clinical trigger status was recorded. Results: Thirty fingers from 24 patients were released; 17 fingers received A0 release first, and 13 received A1 release. Following initial A0 release, 8 fingers (47%) demonstrated complete resolution of symptoms, 4 (24%) demonstrated improvement but incomplete resolution of triggering, and 5 (29.4%) demonstrated no improvement. Following initial A1 release, 6 fingers (46%) demonstrated complete resolution, 3 (23%) demonstrated improvement but incomplete resolution of triggering, and 4 (31%) demonstrated no improvement. All patients demonstrated complete resolution after surgical release of both sites. Neither initial A1 release nor initial A0 release was statistically associated with complete, incomplete, or failed symptom resolution. Conclusions: These data implicate the A0 pulley as the primary cause of 31% to 47% of trigger fingers in our study. Although larger trials are needed to validate these results, our study suggests that release of both A0 and A1 pulleys may offer greater symptom resolution than release of the A1 pulley alone. [ABSTRACT FROM AUTHOR]

Metal recycling casting is an alternative for the development of the foundry industry in Indonesia. The use of scrap metal as industrial raw material is increasing, so that it becomes a trading commodity and encourages the development of metal smelting businesses. The objective is to study the metal casting process of the B3 × 7 inches pulley using the sand casting method and to analyze the defects that appear on the B3 × 7 inch pulley. Pulley is one of the casting products with materials from cast iron which is used as a machine propulsion tool. The raw material from cast iron which is produced itself consists of scrap left over from smelting, gram, charcoal, silica and the addition of slag remover. The resulting cast iron is melted in an induction furnace at a temperature of 1350 - 1450°C. The smelting results are then poured into wet sand molds using a ladle, then the castings are cleaned and checked for defects (quality control) prior to machining and finishing processes. Carried out product analysis and found casting defects that occurred due to external and internal factors such as defects in air voids, crack defects, and collapsed molds (kataochi). [ABSTRACT FROM AUTHOR]

Background. The growing requirements for modern cars are conditioned by environmental agreements of international regulatory bodies in three main areas: energy efficiency, emission reduction and vehicle performance. Variator gearboxes reduce fuel consumption and emissions by ensuring optimal engine performance, as well as provide performance and driving comfort through automatic gear shifting and continuous torque transmission. A significant disadvantage compared to mechanical transmissions is the insufficiently high mechanical efficiency, which significantly affects fuel consumption and, as a result, emissions of harmful substances into the atmosphere. One of the ways to minimize such losses is the formation of pulley surfaces with the necessary roughness and undulation parameters by applying various technological operations. Cutting modes, geometric parameters of the workpiece and physico-chemical properties of the processed metal lead to the occurrence of self-oscillations. Self-oscillations affect the microprofile of the formed surface of pulleys during turning. The object of the study is the relationship between the processing modes and the quality of the surface layer of the friction elements of a continuously variable transmission. The subject of the study is an adequate assessment and quality assurance of the surface during processing by technological methods that ensure the formation of a regular waviness profile of the drive pulley of the variator. The purpose of the study is to develop a technique for determining the undulation of the surface by analytical evaluation of the amplitude of self-oscillations during turning. Materials and methods. The theoretical and experimental research carried out in the work is based on the study of literature, conducted research and the experience of practicing technologists. Results. The empirical dependence of the prediction of the height parameter of undulation depending on the amplitude of the arising self-oscillations is analyzed. An analytical dependence of the amplitude of self-oscillations and the height parameter of undulation during processing is proposed, depending on the cutting modes, taking into account the physico-chemical properties of the workpiece materials. Conclusions. Based on the conducted research and experiments, an approach it is proposed to determine the undulation of the surface by analytical evaluation of the amplitude of self-oscillations during processing, depending on the cutting modes, taking into account the physico-chemical properties of the workpiece materials. This will make it possible to predict and ensure the high-altitude parameter of undulation at the stage of development work and drawing up the technological process of processing parts.

We dissected 192 fingers in 48 fresh cadaveric hands (23 right and 25 left hands from 26 female and 22 male donors) and analysed the incidence, location, length and structure of the five annular and three cruciform pulleys. No statistically significant differences were found between left and right or between male and female hands. The A1, A2 and A4 pulleys were present in all fingers, while the incidence of other pulleys varied. We found 32 different patterns of pulley combinations. The structure of the pulleys also varied. Most important was the variation of A1, which consisted of one to four separate rings. In 18% there was no gap between the A1 and A2 pulleys. A greater understanding of the anatomical variation of the pulley system is beneficial for hand surgeons performing open or percutaneous trigger finger releases and for radiologists examining the area sonographically. [ABSTRACT FROM AUTHOR]

In 3D printer design, special care must be taken when choosing the print head positioning mechanism. Indeed, this choice has a significant influence on the manufacturing accuracy, printing speed, workspace characteristics, and total cost of the printer. Considering 3D printers with layer-based processes, many designs include two stages: a planar mechanism for positioning the nozzle on a horizontal plane and a linear mechanism for the vertical build–plate motion. From the literature, two designs are usually applied for horizontal motion, commercially known as "CoreXY" and "H-bot". Their load distribution characteristics are compared here: it is found that both have significant drawbacks. Therefore, an alternative architecture, called "CoreH-bot," is introduced to overcome such limitations; this mechanism is both fully planar, which greatly simplifies its design and assembly phases while increasing part life, and has low unbalanced torques during motion, which increases the maximum speed for the given accuracy. The CoreH-bot kinematic equations are analyzed to define the Jacobian matrix and the corresponding workspace. The static and dynamic analyses are also performed. A prototype with this architecture has been designed that shows interesting capabilities in terms of print speed, while being both simple and cost-effective to assemble. [ABSTRACT FROM AUTHOR]

Clustered (continuous) cables reflect an advantageous solution for reducing the number of tensile elements in engineering systems. During the tensioning or activation of tensile structures, such as cable structures, membranes and tensegrity structures, the deficiency of having to control too many elements can be overcome by employing clustered cables. The use of clustered cables has been shown to alter the structural behavior of tensile systems by modifying the force distribution in the systems. This effect has been showcased under the assumption of frictionless sliding of the cable elements across nodes or pulleys. However, friction can have also impact on the behavior of the system. In this paper, a new Finite Element formulation is proposed for the static analysis of tensile structures with clustered cables. The proposed formulation accommodates sliding-induced friction by the consideration of the Euler-Eytelwein equation as well as geometric nonlinearities. It is found that the sliding-induced friction can significantly modify the force distribution in the system. The applicability and importance of the proposed formulation is demonstrated through the analysis of two examples from the literature. [ABSTRACT FROM AUTHOR]

Design-based learning has been internationally recognised as a new pedagogical approach to science, technology, engineering, and mathematics (STEM) education at primary and secondary levels. While previous studies have examined its effectiveness in facilitating students' scientific understanding of various topics, it is evident that design-based learning may be less effective in some topics. Design-based learning on the topic of pulleys, which students often have difficulty setting up by themselves, has not yet been implemented. Thus, this study aims to examine the influence of design-based learning on 25 eighth-grade students' understanding of pulleys. Before and after the design-based learning, each student individually completed a conceptual test comprised of 12 multiple-choice questions from the literature. Their mean scores on the pre-test and the post-test were compared using a paired-samples t-test. The results reveal a significant improvement in students' understanding of pulleys with a large effect size. Recommendations for effective design-based learning are proposed for application in other topics. [ABSTRACT FROM AUTHOR]

In lifting systems used for the vertical transport of bulk materials and individual items or persons, so-called frictional force transmission between a steel cable and pulley is used. Due to the sufficient contact pressure between the pulley groove and the surface of the steel cable, the steel cable moves as a result of fibre friction. In general, it is possible to define fibre (also called belt) friction as the resistance that is imposed on a flexible steel cable sliding over the rounded surface of a pulley. The frictional transmission of the tractive force is considered safe if there is no slippage of the cable in the pulley groove. In the event of insufficient cable pressure against the pulley groove or insufficient friction, the transport process fails, and the lifting device is unable to perform its function. The purpose of the article and of the created measuring devices is to obtain by experimental measurements the most accurate true value possible of the coefficient of friction acting on the contact surface of the cable with the pulley groove. The values of the friction coefficients obtained by indirect measurements on laboratory equipment when the tractive force is transferred by friction differ in many cases and do not coincide with the values calculated using theoretical relationships. The aim of the paper is to present a method of measurement and to identify the magnitude of the forces acting on both sides of a cable belted in the V-groove of a cable drum. From the results obtained from the experimental measurements, to express the value of the random variable is based on the knowledge of the known values obtained from the measurements for their use in a failure analysis. This paper presents results that can be applied in the field of online monitoring of this type of lifting equipment for failure analysis, prediction and evaluation of their operational indicators. [ABSTRACT FROM AUTHOR]

Pulley injuries and Dupuytren disease are quite common in rock climbing. We report a rock climber who was treated for a Dupuytren contracture with collagenase injection therapy. Two months later, he developed a traumatic pulley injury during climbing and was treated with a ring orthosis. However, the finger contracture deteriorated and both a recurrent pulley rupture and a second pulley rupture were diagnosed. We were unable to find any reports on the use of collagenase in rock climbers with Dupuytren disease. We report a case of pulley rupture in a rock climber, treated for Dupuytren contracture in the treated and an adjacent finger, 2 months after the injection of collagenase. Level of Evidence: Level V (Therapeutic) [ABSTRACT FROM AUTHOR]

Abstract Background To evaluate the value of 3 Tesla (T) magnetic resonance imaging (MRI) changes of flexor tendon pulleys for the differentiation of psoriatic (PsA) and rheumatoid arthritis (RA), using a novel 16-channel high-resolution hand coil. Methods Seventeen patients with active PsA, 20 patients with active RA, and 16 healthy controls (HC) underwent high-resolution 3 T MRI using the dedicated 16-channel hand coil. Images were analyzed by three independent readers for the degree of inflammatory changes, thickness of flexor tendon pulleys, and comparison to the outcome measures for RA clinical trials (OMERACT) PsA MRI score (PsAMRIS) and to its sub-scores. For correlation analyses, Spearman rho correlation was calculated. Results Flexor tendon pulleys were thicker in PsA than in RA patients (mean difference 0.16 mm, p

The pulley is the functional origin of the extraocular muscles and prevents their dislocation from the muscle cone. The pulley degenerates with age and may progress to cause the sagging eye syndrome (SES). Divergence paralysis, a type of distance esotropia, occurs when the lateral rectus muscle pulley and lateral rectus–superior rectus (LR–SR) band show degenerated symmetry OU. Cyclovertical strabismus of a small angle occurs when the lateral rectus muscle pulley and LR–SR band show degenerated asymmetry OU. Patients with SES have distinctive features, such as baggy eyelids, deep superior sulcus deformity, and aponeurotic ptosis. SES is the leading cause of non-paralytic diplopia, and its rate increases with age, with 60% of the patients being women. One-third of the cases of SES are distance esotropia of 9Δ on average, and two-third of the cases are small-angle hypertropia of 4Δ on average. Diplopia is cured with surgery, and each case needs to be differentiated from the heavy eye syndrome for diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Introduction: Biomechanical evaluation of the viscoelastic properties tissue deformation, stiffness, and maximum breaking load of the human A2 pulley. We hypothesized that the A2 pulleys of index, middle, and ring fingers exhibit no difference regarding the aforementioned biomechanical parameters. Methods: Forty-one A2 pulleys of 14 upper extremities (8 body donors) were assessed. Cyclic and load-to-failure testing were performed. The biomechanical parameters tissue deformation during cyclic and load-to-failure testing, stiffness, and maximum breaking load were determined. Results: No significant differences between the fingers could be detected regarding the biomechanical parameters. A significant negative correlation could be detected between stiffness and deformation of the pulley. Significant positive correlations could be identified between stiffness and maximum breaking load and between maximum breaking load and deformation of the pulleys. Conclusions: Assessment of the viscoelastic properties of the A2 finger pulley promotes precise diagnosis of pulley lesions and will help to optimize treatment. [ABSTRACT FROM AUTHOR]

Tendon injuries represent the second most common injury of the hand (after fractures) and are a common scanning indication in radiology. Pulley injuries are very frequent in rock climbers with the A2 pulley the most commonly affected. Tendon and pulley injuries can be reliably evaluated using ultrasound (US) and magnetic resonance imaging (MRI). US can be postulated as a first-line imaging modality, allowing dynamic examination. MRI is essential for cases with ongoing diagnostic doubt post-US and also for preoperative pulley reconstruction assessment. [ABSTRACT FROM AUTHOR]

Existing drive transmissions are analyzed. A toothed belt transmission with a driven pulley that includes an elastic rubber bush is proposed. Formulas are presented for the kinematic nonuniformity of rotation of the driven pulley, its velocity, and its angular displacement as a result of bush deformation. [ABSTRACT FROM AUTHOR]

Cranes on offshore vessels are subjected to crane dynamics, structural couplings to the vessel, and environmental influence by waves and currents. The recent trend has been to use larger cranes on smaller vessels, which makes the lifting operation more complex and potentially dangerous. The use of digital twins (DTs) is emerging as one way to enable safer operations, real‐time simulation, and maintenance prediction. On offshore vessels, a DT can monitor the lifting operation to create a safer work environment. The SPADE (stakeholders, problem formulation, alternatives, decision making, and evaluation) model has been used as a framework toward the creation of a DT of cranes on offshore vessels. Several cases involving simulation of cranes revealed the lack of an adequate simulation of cable and pulleys suitable for use in a DT. The simulation is important for accurate results and for implementation in control systems. A trade study was performed to determine a numerical method adequate for cable and pulley simulation. The trade study identified the absolute nodal coordinate formulation in the framework of arbitrary Lagrangian–Eulerian as a promising numerical formulation. [ABSTRACT FROM AUTHOR]

We study a simple model of a conveyor belt. We calculate the relation between the torque M and the belt–pulley slip s. We present numerical results for the M(s) relation, and for the frictional energy dissipation as a function of the slip, which is important for the rubber wear. The theory includes both the belt compliance and the pulley tread block stiffness. The theory shows that to minimize the friction and the related rubber wear, the pulley–belt system should be operated not at the slip where the torque is maximal, but at a lower slip. Thus, the belt–pulley system should be slightly "oversized" for the best performance. [ABSTRACT FROM AUTHOR]

Trigger finger is a common pathologic condition of the digital pulleys and flexor tendons in the hand. The key clinical finding is a transient blockage of the digit when it is flexed with subsequent painful snapping when it is extended. Imaging is a helpful guide for establishing the severity of the disease, identifying the underlying cause, and deciding the appropriate management. This narrative review aims to recall the anatomic and pathologic bases and describe the ultrasound features of trigger finger, also including common ultrasound findings and complications after therapy. Ultrasound enables an accurate static and dynamic evaluation of trigger finger as well as a comparison with the adjacent normal digits and thus should be considered the radiologic modality of first choice for its diagnosis. [ABSTRACT FROM AUTHOR]

Background and Study Aims: We have reported the usefulness of traction-assisted colorectal endoscopic submucosal dissection (TAC-ESD) to overcome the technical difficulty of colorectal ESD. However, the direction of traction is toward the anal side only. We retrospectively evaluate the safety and efficacy of "pulley" TAC-ESD. Patients and Methods: We retrospectively analyzed patients diagnosed with colorectal polyps and treated by "pulley" TAC-ESD at Osaka International Cancer Institute from December 2017 to June 2018. Results: During the study period, 79 patients with 81 lesions were treated by ESD, and 54 of these patients were treated by traction-assisted ESD. Among them, 7 underwent "pulley" traction-assisted ESD (6 men, 1 woman; age, 48–69 years), resulting in en bloc resection with no complications. This afforded good visibility of the submucosal layer in 6 patients, but it was not effective in the remaining patient with the muscle-retracting sign. Conclusion: The "pulley" method affords good visibility of the submucosal layer by changing the traction direction in cases that are difficult to manage by conventional traction-assisted ESD. [ABSTRACT FROM AUTHOR]

The pulley is used in a number of structures for the mechanical advantage it gives. This paper presents an approach for the calculation of a pulley-cable system using a special pulley element in the finite element method. The Lagrange Multiplier method and Penalty method are used to define the pulley element, as described in this paper. Both approaches are easy to implement in general FEM codes.

The cable-pulley system is widely used for its advantages. In this paper, application of a new algorithm for the calculation of cables on pulleys is presented. Unlike other algorithms, this algorithm enables to take the magnitude of the radius of each pulley into account. This new algorithm is implemented in the RFEM program because of its higher accuracy and efficiency. Comparison of the commonly used algorithm, which ignores pulley radius, and the new algorithm is presented.

Although various techniques exist for pulley reconstruction, none are useful for all patients. We performed flexor pulley reconstruction using a transverse carpal ligament which has the advantages of a useful gliding surface, sufficient width and thickness, anatomical similarity to the pulley, and adequate durability. Cosmetically, all the surgical scars are on the volar side while functionally, we can avoid invasion to both the flexion and extension sides. [ABSTRACT FROM AUTHOR]

The problem-solving capabilities of four small parrots (peach-fronted conures, Eupsittula aurea) were investigated using string-pulling tests. In seven different tasks, one string was baited following a randomized order. The parrots could retrieve the food reward after a wrong choice as the choice was not forced. Additionally, we applied a non-intuitive pulley task with the strings arranged in front of, instead of below the birds. All four parrots performed very well in the multiple, slanted, and broken string tasks, but all failed in the crossed-string task. Only two parrots solved the single pulley task. All four parrots performed successfully in the multiple pulley task but all failed in the broken pulley condition. Our results suggest that peach-fronted conures solve string-pulling tasks without relying on simple proximity based rules, but that they have evolved cognitive abilities enabling goal-directedness, the understanding of functionality, and a concept of connectedness between two objects. [ABSTRACT FROM AUTHOR]

Injuries to the hand's flexor pulley system can be debilitating, causing pain and restricting movement of the affected finger(s). The creation of a biocompatible artificial pulley could potentially alleviate some of the complications associated with current surgical treatments. In this study, a biocompatible artificial pulley was fabricated by using polycaprolactone (PCL) and polyurethane (PU) in the form of an electrospun nanofiber structure. All scaffolds were structurally analyzed using FESEM imaging, porosity, FTIR, and DSC examinations. Mechanical properties were evaluated, and in vitro studies were conducted on the degradation rate, swelling ratio, and toxicity. Immune response to fabricated scaffolds was evaluated by implanting them under the skin of rats for further pathological examination. All scaffolds exhibited a nanoscale structure and high porosity without any undesirable functional groups. The 25% PCL scaffold showed 17%, 20%, 80%, 17%, and 70% significant increases in F , final stress, final strain, Young's modulus, and elongation percentage, respectively. In fact, the PCL25% scaffold demonstrated more than 100% improvement in mechanical properties compared to those of A2 and A4 natural pulleys. Additionally, all scaffold structures showed cell viability similar to that of the control sample. The study suggests that scaffolds made of 25% PCL hold promise as effective artificial pulleys for reconstructing the flexor tendon pulley system in cases of injury.max , final stress, final strain, Young's modulus, and elongation percentage, respectively. In fact, the PCL25% scaffold demonstrated more than 100% improvement in mechanical properties compared to those of A2 and A4 natural pulleys. Additionally, all scaffold structures showed cell viability similar to that of the control sample. The study suggests that scaffolds made of 25% PCL hold promise as effective artificial pulleys for reconstructing the flexor tendon pulley system in cases of injury.

Purpose: Knowledge of anatomical landmark to pulley system of the thumb is essential in successful treatment of trigger thumb release either by percutaneous or by minimally invasive technique. Though surgical release of trigger thumb is done commonly, there is paucity of data in the literature regarding its surface landmarks. The purpose of this study is to identify palmar surface anatomical landmarks to the pulley system of the thumb.Methods: Dissection was performed on 55 fresh frozen adult cadaveric thumbs. The palmar thumb creases were given names as the proximal-proximal crease (PPC) present at the metacarpophalangeal joint, the distal-proximal crease (DPC) over the middle of the proximal phalanx and the distal crease (DC) at interphalangeal joint. The distance between the proximal edges of each pulley to the three thumb creases and longitudinal length of A1, A2, oblique and Av pulley was measured using digital vernier caliper and was expressed in mean and standard deviation.Results: The proximal edge of A1 pulley was 1.98 ± 1.61 mm proximal to the PPC. The mean longitudinal length of the A1 pulley was measured to be 5.06 ± 0.87 mm, so the distal edge of the A1 pulley was calculated to lie 3.08 mm distal to PPC. The proximal edge of Av and oblique pulley was situated 7.78 ± 2.5 and 15.72 ± 3.22 mm distal to PPC, respectively. The proximal edge of A2 pulley was very nearer and 2.88 ± 1.79 mm proximal to DC.Conclusion: The knowledge of anatomical skin surface landmarks is helpful in the percutaneous release or minimally invasive procedure. The PPC serves as a definite landmark for A1, Av and oblique pulley whereas it is the DC for A2 pulley. [ABSTRACT FROM AUTHOR]

For a cable-driven parallel robot system, the robot kinematic models usually assume that the cable connection in the system comprises ideal fixed points on the base and an end-effector. However, the cables are usually guided around pulleys, so the pulley geometry can induce movable connection points when operating the robot system. Some previous studies have addressed the influence of the geometry of the guiding pulleys on the parallel cable robot’s kinematics, and extended pulley kinematics have been proposed by considering the pulley radius. However, the inverse kinematics of the extended pulley kinematics may hinder the implementation of an actual system, especially owing to the real-time computation capacity. Hence, in this study, to solve the pulley kinematic inclusion problem for a cabledriven robotic system and to improve the position control performance, we investigated the actual pulley kinematic effect and we proposed two methods for a fully constrained planar cable robot. Comparison and evaluations based on simulations and experiments using the proposed methods in terms of the end-effector posture demonstrated their validity for solving pulley inclusion problems for a cabledriven parallel robot. [ABSTRACT FROM AUTHOR]

Many investigators have described the anatomy of the volar retinacular structures of the hand over the last 60 years. As a result, multiple terms have been assigned to 1 anatomical structure and 1 name designated to more than 1 structure. Our purpose is to review the detailed anatomy and key components of the volar retinacular elements of the hand, their etymology, and their most recent descriptions. The objective also is to organize these structures into systems, which can be helpful for learners to assimilate into a practical anatomical guide. Lastly, the goal is to create a common nomenclature for identifying the volar retinacular structures of the hand in order to facilitate clear communication about them across languages. [ABSTRACT FROM AUTHOR]

• Side and radius vectors are proposed to define pulley geometries in the planar CTS. • The nonlinear equilibrium equations are explicitly derived. • The linearized equation and tangent stiffness are explicitly derived. • The clustered/traditional tensegrity without pulley sizes are two particular cases. This paper presents the equilibrium and stiffness study of planar clustered tensegrity structures (CTS) considering pulley sizes. We first derive the geometric relationship between clustered strings and pulleys, where the nodal vector is chosen as the generalized coordinate. Then, the equilibrium equations of the planar clustered tensegrity structure with pulleys based on the Lagrangian method are given. Since the stiffness of a structure is usually weakened when using clustering strings, we formulate the tangent stiffness matrix equations for analysis. It is also shown that as pulley sizes go to zero, the governing equations of the planar clustered tensegrity system with pulleys yield to the classical clustered tensegrity structure without pulleys, which is consistent with the existing literature. Three examples are demonstrated to validate the given theory. The proposed method allows one to conduct equilibrium, stiffness, and robustness studies of planar clustered tensegrity structures with pulleys. Nevertheless, the approach developed in this paper is not limited to tensegrity structures. It can also be applied to a wide range of applications with pulley-rope systems, such as drilling rigs, ocean platform anchors, and cargo cranes. [ABSTRACT FROM AUTHOR]

Purpose: Recently, single-incision thoracoscopic surgery (SITS) has been recognized as a favorable treatment choice for primary spontaneous pneumothorax (PSP) compared with conventional three-port video-assisted thoracoscopic surgery (VATS). However, conventional SITS bullectomy often results in collisions with surgical devices. Therefore, we devised a method of SITS using a chest wall pulley for lung excision (PulLE) and modified PulLE (mPulLE) system, which substitutes threads to eliminate such collisions. We compared the mPulLE system with conventional procedures using propensity score matching (PSM) to adjust for patient backgrounds. Methods: Using PSM, we evaluated the surgical results of 210 PSP patients who underwent VATS, including mPulLE ( n = 23) and three-port VATS ( n = 102), at our institution between January 2010 and August 2016. Results: We selected 17 mPulLE cases and 17 three-port VATS. There were no marked differences between the groups in the patient backgrounds or surgical results. However, there was a significant difference between the mPulLE cases and the three-port VATS cases in the operative time (71.7 ± 15.7 vs. 85.9 ± 25.5 min, respectively, P = 0.0388) and the number of autosutures used (3.6 ± 1.2 vs. 4.5 ± 1.2, respectively, P = 0.0178). Conclusion: The surgical results of mPulLE in patients with PSP with multiple lesions were equivalent to those achieved with three-port VATS under the same conditions. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to analyse the relationship between long head of the biceps brachii (LHBT) lesions and subscapularis tears. The hypothesis was that a bicipital pulley might remain intact, even in the case of a subscapularis tear.Methods: Between 2010 and 2011, all patients who had a primary arthroscopic repair of a subscapularis tear were potentially included in this prospective study. The outcome of interest was the prevalence and type of arthroscopic lesions of the LHBT and bicipital pulley. Furthermore, the supposed pathomechanics of injury and the treatment proposed (conservative, pulley repair, tenodesis, tenotomy, etc.) was recorded. The following baseline characteristics were assessed: age, sex, shoulder side, and limb dominance.Results: Of the 218 patients, the superior glenohumeral ligament/coracohumeral ligament (SGHL/CHL) complex was normal in 54 patients (25%), stretched in 84 patients (39%), and absent in 77 patients (35%). Below the SGHL/CHL complex in the bicipital groove, the medial wall of the LHBT sheath was normal in 25%, partially torn in 39%, and completely torn in 35%. In 25 of the 218 patients (11%), a pathologic LHBT with an intact SGHL/CHL complex was observed. In these cases, the medial wall of the bicipital sheath was torn in 92%.Conclusions: The biceps pulley system, including the SGHL/CHL complex and subscapularis tendon, merits recognition as an important anatomical structure, and its lesions contribute to shoulder pathology. The subscapularis tendon is very important for the stability of the LHBT and should be included in the pulley system. In cases of a tear associated with a lesion of the SGHL/CHL complex, the LHBT is nearly always unstable and pathologic.Level Of Evidence: II. [ABSTRACT FROM AUTHOR]