Journal articles on the topic 'Roller support'
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1
DeBruyne, Danielle M., Marina M. Dewhurst, Katelyn M. Fischer, Michael S. Wojtanowski, and Chris Durall. "Self-Mobilization Using a Foam Roller Versus a Roller Massager: Which Is More Effective for Increasing Hamstrings Flexibility?" Journal of Sport Rehabilitation 26, no. 1 (January 2017): 94–100. http://dx.doi.org/10.1123/jsr.2015-0035.
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Clinical Scenario:Increasing the length of the muscle–tendon unit may prevent musculotendinous injury. Various methods have been proposed to increase muscle–tendon flexibility, including self-mobilization using foam rollers or roller massagers, although the effectiveness of these devices is uncertain. This review was conducted to determine if the use of foam rollers or roller massagers to improve hamstrings flexibility is supported by moderate- to high-quality evidence.Clinical Question:Are foam rollers or roller massagers effective for increasing hamstrings flexibility in asymptomatic physically active adults?Summary of Key Findings:The literature was searched for studies on the effects of using foam rollers or roller massagers to increase hamstrings flexibility in asymptomatic physically active adults. Four randomized controlled trials were included; 2 studies provided level 2 or 3 evidence regarding foam rollers and 2 studies provided level 2 or 3 evidence regarding roller massagers. Both roller-massager studies reported increases in hamstrings flexibility after treatment. Data from the foam-roller studies did not demonstrate a statistically significant increase in hamstrings flexibility, but 1 study did demonstrate a strong effect size.Clinical Bottom Line:The reviewed moderate-quality studies support the use of roller massagers but provide limited evidence on the effectiveness of foam rolling to increase hamstrings flexibility in asymptomatic physically active adults. Flexibility gains may be improved by a longer duration of treatment and administration by a trained therapist. Gains appear to decline rapidly postrolling. Neither device has been shown to confer a therapeutic benefit superior to static stretching, and the effectiveness of these devices for preventing injury is unknown.Strength of Recommendation:Grade B evidence supports the use of roller massagers to increase hamstrings flexibility in asymptomatic physically active adults.
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Danilin, Oleksandr, Stefan Zaichenko, Stepan Shevchuk, Natalia Jukova, and Ivan Pasichniuk. "DETERMINATION OF THE CHANGE OF THE DESIGN POSITION OF THE PROFILE OF THE BELT CONVEYOR ON THE LOAD OF THE ROLLER BEARINGS." Geoengineering, no. 3 (December 14, 2020): 20–25. http://dx.doi.org/10.20535/2707-2096.3.2020.219324.
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The article attempts to establish the basic patterns in the formation of loads in the structure of the conveyor frame due to changes in the design position of the constituent elements based on analytical calculations. The amortization replacement of rollers and the establishment of a change in the projected resource caused the change in the design position.The aim of the work is to study the interaction of the elements of the belt conveyor on the convex region of the profile when the design position changes and to determine the change in the resource of the roller support elements. The purpose of the work is formulated from the analysis of unplanned stops and premature replacement of conveyor elements, in particular conveyor rollers, on the convex region of the profile.To achieve this goal the influence of the geometric parameters of the convex section of the belt conveyor profile on the force interaction of the belt and roller supports was considered, and the change in the resource of the roller bearings was determined.To characterize the geometric parameters of the convex section of the belt conveyor, the following were selected: the number of roller supports, the distance between the roller supports, the radius of curvature of the conveyor profile, the angle of the curved section. The mathematical model is based on the belt equilibrium equation, which contains the tension forces of the conveyor belt and the forces from the action of roller supports. Particular attention is paid to establishing the effect of changing the geometric parameters of the convex section on the roller bearing life. It has been established that a decrease in the radius of the transitional convex section as a result of a change in the initial design position by 2.4 times leads to an increase in the force acting on the roller support by 161%. It was found that the increase in force is the reason for the rapid exit from the operational state of the rolling bearings of the roller bearings, as evidenced by the intensive drop in the resource of the rollers (18 times).The proposed algorithm for determining the main parameters of the force interaction of the elements of the belt conveyor on the convex region of the profile will make it possible to predict the resource and prevent the conveyor from leaving the premature operational state.
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Park, Cheol Hoon, Tae Gwang Yoon, Dongwoo Kang, and Hugo Rodrigue. "High-Precision Roller Supported by Active Magnetic Bearings." Applied Sciences 9, no. 20 (October 17, 2019): 4389. http://dx.doi.org/10.3390/app9204389.
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Magnetic bearings support rotors in a non-contact way using magnetic force. Therefore, there is no friction and it is possible to measure and control the position of a rotor in the air gap. In this study, the rotational vibration of a roller was minimized using magnetic bearings, and a precision roller capable of automatic alignment using the position control function of magnetic bearings was proposed. A rotation accuracy of approximately 4.6 μm (peak-to-peak) was observed, even under a rotation of 30 rev/min and a radial force load of 300 N. The rotor position control experiment for magnetic bearings showed that 1-μm resolution position control is possible. To further improve the accuracy, the automatic alignment algorithm was proposed using magnetic bearings for the roller misalignment condition, and it was confirmed that alignment is possible at a level that the pressing force difference between both ends of the roller is within 0.3 N. Through this study, it was confirmed that rollers with magnetic bearings can be applied to precision equipment. It is expected that the implementation of the automatic alignment function will simplify the equipment configuration and maintenance compared to conventional rollers with ball bearings.
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Wang, Xiao Gang, Xiang Nan Li, and Qing Xue Huang. "Research on Force Simulation of Rolls' Deformation in the Rolling Process of Medium and Heavy Plate Leveler." Applied Mechanics and Materials 143-144 (December 2011): 517–21. http://dx.doi.org/10.4028/www.scientific.net/amm.143-144.517.
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During many factors affect the straightening precision, the shape of roller gap affect directly the flatness and the distribution of residual stress; At the same time, roll system's stiffness, as an important part of the roller leveler's whole stiffness, affect directly the design of leveling production process. In order to draw the conclusion of deformation characteristics and rules, the equivalent FEM Model on upper rolls and its support structure and investigates on the features of stress and strain after the rollers' deformation is established, based on the structural analysis of hot roller leveler for 3800mm plate steel.
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Safronov, Ye V., and A. L. Nosko. "Experimental evaluation of the load capacity of the rollers of gravity conveyors for pallets." Izvestia MGTU MAMI 1, no. 3 (2020): 59–64. http://dx.doi.org/10.31992/2074-0530-2020-45-3-59-64.
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The main approaches to calculating the load capacity of the carrying rollers of gravity conveyors are presented. It is shown that in practice, in the designs of modern non-driven conveyors for pal-lets, the priority when choosing the pitch of the carrier rollers is the stability of the movement of the load, rather than minimizing the number of rollers. In connection with the urgent task of reducing the metal consumption and the cost of gravity roller conveyors for pallets, the purpose of the work is to experimentally determine the load capacity of the rollers of gravity conveyors for pallets with plastic bearing housings. The experimental studies were carried out in the laboratory of the Depart-ment of Applied Mechanics on a Galdabini Quasar 50 universal testing machine using a special roller support for two roller designs - with a solid axis and on half-axles. The test results showed that the stiffness of a roller with a solid axis in the load range up to 670 N is about 1358.4 N / mm, and in the load range from 670 to 1500 N - 2229.9 N / mm. The rigidity of the roller on the axle shafts in the entire load range is 2048.0 N / mm. The analysis of the obtained results showed that for loads over 670N the use of the axle slightly increases the stiffness coefficient, and, on the contrary, it decreases in the load range up to 670N. In order to reduce the cost of carrying rollers with plastic bearing housings, it is advisable to use a design on semi-axles.
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Listova, M. A., V. V. Dmitrieva, and P. E. Sizin. "Reliability of the belt conveyor bed when restoring failed roller supports." IOP Conference Series: Earth and Environmental Science 942, no. 1 (November 1, 2021): 012002. http://dx.doi.org/10.1088/1755-1315/942/1/012002.
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Abstract The reliability of modern belt conveyors, whose length reaches tens of kilometers, is primarily determined by the reliability of the roller supports that support the belt and ensure its movement. As they wear out, some roller bearings fail and need to be repaired or replaced. The dynamics of the number of working roller supports is determined by the system of Kolmogorov equations. Their solution allows us to find the probabilities of finding the system in states with a different number of working elements. The article finds probabilities for two cases. In the first case, when restoring, only one roller support is repaired each time. In the second case, all roller supports are repaired or replaced. In the case of sequential recovery, the mathematical expectation of the number of properly working roller supports may be less than the total number by several units. There are always elements that need to be repaired. If the recovery rate of the elements is many times higher than the failure rate, the mathematical expectation of the number of properly operating roller supports is less than the total number of roller supports by less than one, during most of the time all roller supports are serviceable. In the case of simultaneous recovery of elements, an equally high level of reliability is achieved even with comparable failure and recovery rates. The results obtained can be used to determine the necessary reserve of spare structural elements and to plan the maintenance of conveyors.
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Zheng, Jingyang, Jinchen Ji, Shan Yin, and Van-Canh Tong. "Fatigue life analysis of double-row tapered roller bearing in a modern wind turbine under oscillating external load and speed." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 15 (March 17, 2020): 3116–30. http://dx.doi.org/10.1177/0954406220911966.
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Fatigue life analysis of roller bearing is usually performed for bearings under constant rotating speed and invariant loading conditions. For the bearings used in offshore floating direct-drive wind turbines, they often experience oscillating motions with varying loading patterns, for which the standard fatigue life analysis is not valid due to the presence of fluctuating loads. This paper presents the fatigue life analysis of a double-row tapered roller bearing under oscillating external load and speed conditions, which is used to support the main shaft of a large modern direct-drive wind turbine. First, a comprehensive quasi-static model of the double-row tapered roller bearing is developed for determining the internal load distribution of rollers. The contact pressure of rollers is then studied using an iterative scheme based on the elastic contact model. After that, the formulation of basic rating life of the double-row tapered roller bearing with oscillating external load and speed is given to calculate the fatigue life. Numerical simulations are carried out to investigate the effects of the oscillating load and speed, angular misalignment, and internal clearance on the fatigue life of the bearing.
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Cao, Shunxin, Ruijun Zhang, Shuohua Zhang, Shuai Qiao, Dongsheng Cong, and Mingxiao Dong. "Roller–rail parameters on the transverse vibration characteristics of super-high-speed elevators." Transactions of the Canadian Society for Mechanical Engineering 43, no. 4 (December 1, 2019): 535–43. http://dx.doi.org/10.1139/tcsme-2018-0083.
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Interaction and wear between wheel and rail become increasingly serious with the increase in elevator speed and load. Uneven roller surface, eccentricity of rollers, and the looseness of rail brackets result in serious vibration problems of high-speed and super-high-speed elevators. Therefore, the forced vibration differential equation representing elevator guide rails is established based on Bernoulli–Euler theory, and the vibration equation of the elevator guide shoes and the car is constructed using the Darren Bell principle. Then, the coupled vibration model of guide rail, guide shoes, and car can be obtained using the relationship of force and relative displacement among these components. The roller–rail parameters are introduced into the established coupled vibration model using the model equivalent method. Then, the influence of roller–rail parameters on the horizontal vibration of super-high-speed elevator cars is investigated. Roller eccentricity and the vibration acceleration of the car present a linear correlation, with the amplitude of the car vibration acceleration increasing with the eccentricity of the roller. A nonlinear relationship exists between the surface roughness of the roller and the vibration acceleration of the car. Increased continuous loosening of the guide rail results in severe vibration of the car at the loose position of the support.
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Bakhshi, Nima, and Mehdi Hojjati. "Effect of compaction roller on layup quality and defects formation in automated fiber placement." Journal of Reinforced Plastics and Composites 39, no. 1-2 (August 6, 2019): 3–20. http://dx.doi.org/10.1177/0731684419868845.
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Application of automated fiber placement is limited by defects formed in the prepreg tows during the layup process. An extensive experimental study is performed to investigate the effect of compaction roller on the quality of the layup. Five different compaction rollers with different stiffness and architectures were manufactured and employed to dispense prepreg tows at various process conditions. Layup quality was examined and different defects including tow buckling and blister were identified. In addition to automated fiber placement trials, static testing and finite element simulations were performed to probe the pressure distribution and contact width of each roller. This data was used to support and understand the results of the automated fiber placement trials. Results indicate the solid elastomer rollers that are compliant enough to produce the same level of contact width under similar levels of compaction forces are superior to the perforated rollers in terms of achievable layup quality.
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Simisinov, D. I., A. I. Afanas’ev, and N. G. Valiev. "Reducing the load on the roller bit support." Mining informational and analytical bulletin, no. 11-1 (2021): 197–208. http://dx.doi.org/10.25018/0236_1493_2021_111_0_197.
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Sun, Li Gen, Hui Rong Li, and Jia Quan Zhang. "Minimum Mould Exit Shell Thickness of Round Blooms for Peritectic Steel Casting." Advanced Materials Research 421 (December 2011): 179–83. http://dx.doi.org/10.4028/www.scientific.net/amr.421.179.
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The minimum mould exit shell thickness (MEST) is one of key factors to consider for continuous casting machine design and the strand cooling schemes. Based on the shell strength at elevated temperatures, a concept of shell integral average strength, from its very top surface to the solidus frontier, has been introduced to judge its bulging tendency under ferrostatic pressure. Considering the contribution to the shell stability, a mathematic model for the determination of the minimum MEST has been brought forward. It is shown that, the minimum MEST of the round bloom is decided by not only the cross section and the minimum roller spacing, but also the opening degree of the support roller and the support roller on the side. Taking a round bloom casting of plain carbon steel (grade Q235) as an example, there is the cross point with the curve of the minimum MEST by the minimum roller spacing and the minimum MEST by the fluting include angle of the support roller and the support roller on the side against the cross section, if its own geometry structure cannot hold the ferrostatic pressure, the minimum MEST on the left of the cross point can remain as the determined amount by the minimum roller spacing; but on the right, it is increased with the increasing width of cross section.
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Huang, Yi Lei, Guang Xun Wang, Han Chao He, and Jing Zhang. "A Research on Automatic Detection Device for the Missing of the Roller Chain's Rollers and Sleeves." Advanced Materials Research 898 (February 2014): 638–43. http://dx.doi.org/10.4028/www.scientific.net/amr.898.638.
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The set of automatic detection device for the parts missing of the roller chains rollers and sleeves is based on the displacement transfer theory of the lever mechanism and combined with the integration of PLC control. The levers one end is the detection head close to the roller chain and the other end is the induction head, its support is placed on the base. Sensor puts the induction information into the PLC, and then the PLC make the Synthetic judgment to control the chains drive mechanism to slow down and marking on the places that have missing some parts on time. Its a device has high reliability and high efficiency, which can realize auto-running to replace manual check perfectly.
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Burlakov, Yu V. "Using the roller threshing device for threshing fiber flax." Siberian Herald of Agricultural Science 50, no. 6 (December 31, 2020): 115–23. http://dx.doi.org/10.26898/0370-8799-2020-6-13.
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The ways of increasing efficiency of the factory technology for harvesting fiber flax with threshing stem band from the rolls were studied. The experiment was carried out in stationary conditions with a moisture content of the source material of no more than 16%. A roller threshing device was proposed for separating the seed part of the crop from the stem before feeding stems into the fiber production line. The device ensures threshing of the fiber flax stem band over its entire width without using a separate clamping conveyor. The places where the seed heap descends from the roller threshing device while threshing flax stem band were identified. Quality indicators of the roller threshing device operation were obtained ensuring 100% threshing of the fiber flax band with a band compression force between the rollers of 16 kN. With this method of threshing, damage and crushing of seeds were not noted, the stems were evenly flattened along their entire length. Fractional composition of the threshed heap was determined during threshing of a fiber flax stem band between the rolls of the laboratory sample of a three-roll threshing device: loose seeds (50%), shells of capsules with fruitstalks (47), capsules with seeds (3), heap of leaves and stems (less than 1%). The results of the study in stationary conditions showed the expediency of using roller working bodies to separate the seed part of the crop from the stem part for the technical support of the factory technology for harvesting fiber flax. The use of roller working bodies in the design of threshing devices without a separate clamping conveyor allows to increase the quality and quantity of flax products obtained both in seeds and in fiber due to the improvement of the process of gentle flattening of the stem band between the rollers along its entire width. The concept of this roller threshing device is advisable to use when designing trailers and travelling flax harvesting machines for the implementation of a separate technology for harvesting fiber flax.
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Gibbons, Timothy J., and Marie-Louise Bird. "Exercising on Different Unstable Surfaces Increases Core Abdominal Muscle Thickness: An Observational Study Using Real-Time Ultrasound." Journal of Sport Rehabilitation 28, no. 8 (November 1, 2019): 803–8. http://dx.doi.org/10.1123/jsr.2017-0385.
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Background: The training of abdominal muscles has a positive impact on the functional capacity of healthy adults, being applied practically in fields of athletics and fitness through rehabilitation for lower back pain. Objective: The study compares abdominal muscle activity while performing graded isometric exercises on stable and unstable surfaces. The authors also examined perceived stability and comfort for the different surfaces. Methods: A total of 30 young, healthy adults performed 3 graded isometric exercises on a Pilates table, foam roller, and Oov (a newly developed tool). Ultrasound investigation measured transversus abdominis, internal oblique abdominis, and external oblique abdominis thickness during each task, comparing muscle thickness between conditions using general linear modeling. Results: Core abdominal activation was greater on the foam roller than the Oov and Pilates table during crook lying (bilateral leg support). Both Oov and foam roller elicited greater contralateral transversus abdominis and internal oblique abdominis thickness than the Pilates table during tabletop and straight leg raises (unilateral leg exercises). For transversus abdominis only, the foam roller elicited more muscle thickness than the Oov during straight leg raises. The Oov was rated more comfortable than the foam roller. Discussion: Exercises performed on the Oov and foam roller elicit core greater abdominal muscle thickness than those performed on a Pilates table. Unilateral leg exercises in a supine position elicit more contralateral muscle thickness than those with bilateral leg support. Conclusions: These results provide information to support choices in exercise progression from flat stable to more unstable surfaces and from those with bilateral foot support to unilateral foot support. The Oov was more comfortable that the foam roller, and this may help with exercise adherence.
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Yin, Ming, and Li Zhong Wang. "Fracture Reason Analysis of Coal Compactor Roller Shaft." Advanced Materials Research 490-495 (March 2012): 2323–27. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.2323.
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The cause of the fatigue fracture of the coal compactor roller shaft is analyzed in this paper. By means of investigating the macro-fracture and micro-fracture analysis for the shaft roller, and use ANSYS software to simulate the fatigue stress to find out the reasons of the roller shaft fracture and thus provides theoretical support for further optimizing the design of the roller shaft structure.This lied a solid foundation for how to improve the designation of roller shaft and how to improve the lifespan of the roller shaft
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Powell, N. N., and C. Andrew. "Incremental Forming of Flanged Sheet Metal Components Without Dedicated Dies." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 206, no. 1 (February 1992): 41–47. http://dx.doi.org/10.1243/pime_proc_1992_206_054_02.
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This paper describes research that has investigated a process for forming flanged sheet metal parts without dedicated tooling by repeated localized deformation—an incremental process. The complete formation of a shrink flange over a former by a grooved roller, moving around the flange in a series of passes, is analysed by the finite element method and reasonable agreement with experimental results shown. Some evidence is presented that the use of a grooved roller can extend the forming limits of a conventional single die pressing operation. The predicted reaction distribution at the fixed edge of a variety of flanges during their incremental formation by different rollers is then examined. It is shown that the most significant reactions are limited to the vicinity of the current position of the roller. This result leads to a proposal that the form tool might be replaced by non-dedicated tooling, to support the component web only in the region near to the roller. This proposal is tested experimentally and the principle of a dieless flange-forming process is successfully demonstrated. Such a process may be of benefit to any industry that produces a variety of flanged parts in small batches, for example airframe manufacture. Further research is proposed to develop a prototype machine based on the principle outlined here.
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Song, Yan Ming, and Yang Yang. "Hydrostatic Support Design of Cooling Copper Roller with Inner Pressure Feedback in Forming Amorphous Ribbon." Applied Mechanics and Materials 364 (August 2013): 46–51. http://dx.doi.org/10.4028/www.scientific.net/amm.364.46.
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Cooling copper roller is the key technology and equipment to amorphous ribbon forming. Rolling bearing support is difficult to obtain high rotation accuracy. A new inner pressure feedback hydrostatic journal bearing is proposed with different recess area. The load capacity and film stiffness mathematical model of hydrostatic journal bearing are established. The Inner pressure feedback hydrostatic journal bearing with different recess area at the diameter of 200mm is designed and manufactured for amorphous ribbon cooling copper roller support structure. The operation tests demonstrate that the rotation accuracy of the cooling copper roller shaft is less than 2μm, which in accordance with the requirements of amorphous ribbon production process.
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Mlambo, S., C. L. Sole, and C. H. Scholtz. "Phylogeny of the African ball-rolling dung beetle genus Epirinus Reiche (Coleoptera:Scarabaeidae:Scarabaeinae)." Invertebrate Systematics 25, no. 3 (2011): 197. http://dx.doi.org/10.1071/is10032.
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Recent phylogenetic analyses have pointed to the dung beetle genus Epirinus as the putative African ancestral roller group. Consequently, we tested the roller status of species in the genus with observational studies and constructed a molecular phylogeny based on partial sequences of two mitochondrial and two nuclear genes for 16 of 29 species. Tested species were confirmed to be dung rollers. Monophyly of the genus was confirmed, lending support to the synonymy of the wingless genus Endroedyantus with Epirinus. Moreover, the phylogenetic hypothesis was found to have a similar topology with a previously published one based on morphological data. A combined molecular and morphology analysis showed congruence between the molecular and morphological datasets. The loss of flight in some species and estimated divergence dates within Epirinus are discussed.
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Polyblank, James A., and Julian M. Allwood. "Support Roller Control and Springback Compensation in Flexible Spinning." Procedia Engineering 81 (2014): 2499–504. http://dx.doi.org/10.1016/j.proeng.2014.10.357.
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Wang, Hui, Min Hui Tong, and Pei Zheng. "Research on Contact Strength between Roller Screw Pair on Hoisting Mechanism Applied in Deep Sea Crane." Applied Mechanics and Materials 423-426 (September 2013): 2001–5. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.2001.
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Roller screw pair is the major part of the rope guiding device that used in deep-sea hoisting mechanism. This paper focuses on the contact problems of the roller screw pair. The hoisting mechanism used in the deep sea engineering has the rope with large diameter, sustaining the great rope tension force. So its important to research the contact stress of the roller screw, This paper study the impact of surface hardness of the roller on the performance of the roller screw, sums up the effect of hardness on the bearing capacity of the roller, and provides the theoretical support and references for the designing and application of this new type of roller screw in marine engineering.
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Ivanović, Gradimir, Radivoje Mitrovic, and Dragan Jovanovic. "Reliability of Transportation Belt Rollers Used in Surface Coal Digging." Advanced Materials Research 633 (January 2013): 312–21. http://dx.doi.org/10.4028/www.scientific.net/amr.633.312.
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Transport of ground and coal at the surface coal dig in Kostolac, Serbia, is done using transportation belts (3 - 5 kilometres in length) using the systems of BTR (Bagger-Transporter-Remover) and BTM (Bagger-Transporter-Mill). The transporter belt during circular movement is suspended on carry-rollers (during transport of weight) and on support-rollers (without weight). Two or three carry-rollers, or three support-rollers make a garland. Garlands (5 carry and 3 supporting) are built into a section and they enable the movement of belt over them. The number of sections depends on the transportation system length. Reliability of these systems is governed by the reliability of the carry and support rollers. In order to determine the reliability of the BTR and BTM systems, reliability analysis of both carry and support rollers was performed using the method of Fault Tree Analysis (FTA) and Reliability Block Diagrams (RBD). In this paper the assessment of roller reliability is described using the FTA method with failure elements. The reliability function was determined on the basis of the RBD in the case where all of the constructive elements of the rollers are in operation the complex relationship, and when some of the elements are in failure mode the quasi-complex relationship.
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Pavlidis, Adele, and Wendy O’Brien. "Sport and feminism in China: On the possibilities of conceiving roller derby as a feminist intervention." Journal of Sociology 53, no. 3 (July 29, 2017): 704–19. http://dx.doi.org/10.1177/1440783317721349.
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The spread of contemporary roller derby presents an opportunity to examine the ways sport can act as a form of feminist intervention. This article draws on a qualitative case study of a roller derby league in China, made up predominantly of expatriate workers, to explore some of the possibilities roller derby presents in activating glocal forms of feminist participatory action. The globalization of sport has often been associated with colonialism and the loss of local physical cultures, together with commercialization. Roller derby provides a very different case, where, together with the spread of the game, comes a focus on gender diversity, female strength and a particular derby style of DIY (do-it-yourself) governance that may support forms of participatory action. As an exploratory study, this article points towards the potential of roller derby, and possibly other sport cultures, to support human rights activism in the Asia Pacific.
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Antipin, Dmitriy, Vladimir Vorob'ev, Maksim Maslov, and Vadim Korchagin. "DEVICE FOR RESEARCHES OF MAGNETIC FIELD IMPACT UPON “WHEEL-RAIL” FRICTION PAIR CHARACTERISTICS." Bulletin of Bryansk state technical university 2020, no. 1 (January 17, 2020): 34–39. http://dx.doi.org/10.30987/1999-8775-2020-2020-1-34-39.
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The paper is dedicated to the circuit diagram substantiation of the specialized roller bench for researches of the magnetic field impact upon wheel adhesion with a rail. On the basis of the analysis of the experimental plants available at present for the study of the contact interaction of wheels with rails it is defined that two-roller benches are the most efficient for the investigation of different outer factors impact upon wheel adhesion with a rail. Taking into account mentioned above there is offered an original design of the two-roller bench equipped with the device for friction area magnetization. Two cylinders with parallel axes are theoretically a friction pair. Taking into account the presence of a non-concurrency arisen at roller manufacturing and mounting a point contact is realized in the bench. A bench formation is carried out according to a modular approach with the installation of rotary magnetic conductors. For the support of the largest magnetization of a friction area in longitudinal and transverse directions and for the decrease of stray flux in the bench there is realized a series connection of roller friction area with the sources of a magnetizing force. For the substantiation of rotary magnetic conductor position choice regarding a friction area of bench rollers there is carried out an analysis of magnetic field distribution in the friction area depending on the location of magnetic conductors. On the basis of the investigation results it is defined that a change of magnetic conductor position changes the orientation of a magnetic field vector, at that a roller friction area is magnetized in transverse and longitudinal directions.
In view of this the bench design offered allows investigating the impact of longitudinal and cross magnetic fields upon friction in the contact of a wheel with a rail. Furthermore, it is defined that at small values of an angle between the direction of a magnetic field vector and the plane of a roller friction area a possibility to exclude the effect of roller magnetic additional loading appears.
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Tilloev, K. Z., and S. V. Kondakov. "METHOD OF CALCULATION THE STABILITY OF AN EXCAVATOR EQUIPPED WITH A CONE ROLLER." Spravochnik. Inzhenernyi zhurnal, no. 294 (September 2021): 12–16. http://dx.doi.org/10.14489/hb.2021.09.pp.012-016.
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The construction and method of calculating the stability of a crawler excavator equipped with a new working body (cone roller) are considered. The calculation is made on two working positions (longitudinal and transverse) of the excavator, provided that the excavator must apply the maximum force on the working body at an angle of 90°. The force applied by the excavator boom to the cone roller during the introduction depends on the physical and mechanical properties of the compacted soil. The calculation method differs in that during the compaction of the roadbed, the cone sinks into the ground, and the excavator tends to roll in the direction of the rear track support roller, in contrast to the traditional danger of tipping over the front support roller when working with a bucket.
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Wei, Yan Gang, and Yan Kui Liu. "Finite Element Analysis of the Roller Bearing Used in Rolling Mill." Applied Mechanics and Materials 367 (August 2013): 141–44. http://dx.doi.org/10.4028/www.scientific.net/amm.367.141.
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The loading roller number and maximum stress of the bearings can not be calculated accurately through conventional methods because support manner of the roller bearings used in rolling mill is different from that of the roller bearings used in conventional condition. Based on characteristic of the bearings, the model of the bearing is made combining contact mechanics with finite element method. The loading roller number and maximum stress of the bearings are calculated through FEA. The work of this paper offers a reference to design and manufacture this kind of bearings.
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Deák, Krisztián, and Imre Kocsis. "Support Vector Machine with Wavelet Decomposition Method for Fault Diagnosis of Tapered Roller Bearings by Modelling Manufacturing Defects." Periodica Polytechnica Mechanical Engineering 61, no. 4 (September 29, 2017): 276. http://dx.doi.org/10.3311/ppme.10802.
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Tapered roller element bearings are generally applied in machines and transmission gearboxes. In manufacturing outer ring, inner ring and the rollers usually suffer damages. It is a challenging task to reveal and classify the defects. This paper presents an efficient method for fault classification by support vector machines. The faults on the bearing parts created by laser beam machine have similar shape and surface topography as the grinding faults from the manufacturing process. Vibration signature is collected by sensitive transducer and high resolution data acquisition unit. A test-rig is constructed to model the circumstances of the operation of the built-in tapered roller bearings. Moreover, test-rig is planned with the aim to mitigate the harmful vibration components from the environment that influence the precision of the vibration measurement. Feature extraction is executed by wavelet decomposition. Decomposition level is determined by FFT considering the structural frequencies of the bearing elements. The proper wavelet is selected by the Energy-to-Shannon Entropy criteria from Daubechies and Symlet wavelet families. The fault classification is done by R Cran software using support vector machine classifiers. Time domain parameters of the vibration signature such as kurtosis, skewness, crest factor and range are provided to the classifier. Classification rates are high enough to ensure the efficiency of the method in all cases in the study.
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Zhao, Xue You, Zhi Chao Lang, Chun Feng Mao, and Wei Na Zhang. "Analysis on Crack Propagation of Roll by the Finite-Element." Advanced Materials Research 591-593 (November 2012): 553–56. http://dx.doi.org/10.4028/www.scientific.net/amr.591-593.553.
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Roller is a main tool and consumption parts for steel rolling. With analysis test on the fatigue property of roller, the development incentives of crack propagation were realized, the service life of roller was improved and the cost of Production was reduced in a large extent. Roller is a circular column, which do fixed-axis rotation under combined action of roll pressure, bearing reaction, Support roller reaction force and torsion. The failure types of roll such as flaking, fracture and crack. Simulate and analysis on damage of the roller crack by the fracture mechanics of knowledge and ANSYS, which shown that compressive was large with the ring and axial and compressive was small with the radial direction, so the compressive of radial direction the analysis had little effect on roll surface.
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Chen, Yang, Longsheng Lu, Xiaokang Liu, Yingxi Xie, Zhenping Wan, and Zhaorui Hou. "Comparative investigation of carbon fiber filaments in off-axis transverse cutting between flexible-support and non-support method under pre-tension." Journal of Engineered Fibers and Fabrics 14 (January 2019): 155892501983781. http://dx.doi.org/10.1177/1558925019837812.
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Short carbon fiber is an effective and essential reinforced material in composite domains. Generally, it is produced by chopping technology, among which pressing roller and grooved wheel are two popular chopping techniques. According to the working principle of these two techniques, the pressing roller can be simplified as a flexible-support cutting in off-axis transverse cutting, meanwhile the grooved wheel can be represented by a non-support cutting. To reveal the fracture difference of carbon fiber between the pressing roller and the grooved wheel technique, comparative investigation of failure behavior between a single carbon fiber (also simplified as a filament) with flexible support and with non-support was performed in off-axis transverse cutting using a custom-designed fixture. Both the cutting force and the fracture surface of the filament were comparatively analyzed in cutting process. It was found that the failure of single carbon fiber was caused by tensile effect in a non-support cutting, whereas that in a flexible-support cutting was caused by bending effect. The cutting-off force and cutting-off depth of filament cut by use flexible support are significantly lower than that by use non-support under low pre-tension. It is interesting to find out that the failure spot of carbon fiber filament in non-support cutting under low pre-tension tends to occur randomly. Meanwhile, in a flexible-support cutting, the break point of carbon fiber filament is determined by the tip of the blade. After a comprehensive comparison, the flexible-support cutting is a prior selection to produce short carbon fibers compared with the non-support cutting.
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Nozdrzykowski, Krzysztof, Zenon Grządziel, and Paweł Dunaj. "Analysis of Contact Deformations in Support Systems Using Roller Prisms." Materials 14, no. 10 (May 18, 2021): 2644. http://dx.doi.org/10.3390/ma14102644.
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This article presents the results of finite element analyses of the influence of reaction forces on stresses and strains at the contact points of the rollers of prism supports with cylindrical surfaces of the main journals of large-sized crankshafts. The analyses of strains and stresses, as well as the depth of their occurrences, in the case of the shaft journal and support rollers were carried out using Hertz contact theory and the finite element method. These calculation results proved to be highly consistent. Additionally, they provide a basis for stating that, in the case under consideration, permanent deformations do not significantly affect the values of the measured geometrical deviations nor the profile forms of the supported main crankshaft journals.
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Volsky, V. A., and R. V. Kotsyubansky. "Development of a structural and functional diagram of an aggregate for grinding and incorporating coarse stem plant residues into the soil." Mehanization and electrification of agricultural, no. 12 (2020): 36–43. http://dx.doi.org/10.37204/0131-2189-2020-12-4.
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Annotation Purpose. Increasing the efficiency of crushing operations and embedding coarse-stem plant residues into the soil due to the improvement of the technological process using a combined unit containing a crusher roller, disc working bodies and a compactor roller. Methods. The research was carried out using synthesis analysis, correlation-regression analysis, which makes prediction of the output quality and energy indicators for certain operating conditions and certain parameters of the combined machine for processing corn stubble. The rational values of design parameters and operating modes were determined based on the results of solving the problem of optimizing energy costs and quality indicators within one module with established internal factor relationships and relationships that arise when working bodies interact with the plant environment and soil. Results. A structural and functional diagram of a combined unit has been developed, in which a shredder roller in combination with a disc harrow and a compactor roller improves the quality of processing operations with simultaneous crushing and harvesting plant residues into the soil. The trailed combined unit contains a towing device, a frame, support wheels for moving in the transport position, a section of crusher rollers, a section of cut spherical disc working bodies, a section of solid spherical disc working bodies, mechanisms for adjusting the angles of attack of sections of spherical discs, sections of compaction rollers. Conclusions 1. The technological process of crushing (up to 5 cm) of plant residues of coarse-stem crops, their earning, mixing with the soil and spreading over layers to a depth of 25 cm, rolling the treated soil and leveling the field surface has been improved, reduces the development of corn moth. 2. A structural-functional diagram has been developed and a combined unit has been manufactured, the main difference of which is the use of a mounted module-roller-grinder, which intensifies the grinding process and earns coarse-stem plant residues into the soil, increases the quality indicators of the technological operation by the amount of crushed plant residues less than 5 cm to 70–80%. Keywords: corn, plant debris, grinding, making plant debris, tillage, combined unit.
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Ao, HungLinh, Junsheng Cheng, Kenli Li, and Tung Khac Truong. "A Roller Bearing Fault Diagnosis Method Based on LCD Energy Entropy and ACROA-SVM." Shock and Vibration 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/825825.
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This study investigates a novel method for roller bearing fault diagnosis based on local characteristic-scale decomposition (LCD) energy entropy, together with a support vector machine designed using an Artificial Chemical Reaction Optimisation Algorithm, referred to as an ACROA-SVM. First, the original acceleration vibration signals are decomposed into intrinsic scale components (ISCs). Second, the concept of LCD energy entropy is introduced. Third, the energy features extracted from a number of ISCs that contain the most dominant fault information serve as input vectors for the support vector machine classifier. Finally, the ACROA-SVM classifier is proposed to recognize the faulty roller bearing pattern. The analysis of roller bearing signals with inner-race and outer-race faults shows that the diagnostic approach based on the ACROA-SVM and using LCD to extract the energy levels of the various frequency bands as features can identify roller bearing fault patterns accurately and effectively. The proposed method is superior to approaches based on Empirical Mode Decomposition method and requires less time.
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Chen, Hongyue, Kun Zhang, Mingbo Piao, Xin Wang, Jun Mao, and Qiushuang Song. "Virtual Simulation Analysis of Rigid-Flexible Coupling Dynamics of Shearer with Clearance." Shock and Vibration 2018 (2018): 1–18. http://dx.doi.org/10.1155/2018/6179054.
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A model for virtual simulation analysis of the rigid-flexible coupling of a shearer has been developed with the objective of addressing problems associated with lifetime mismatch and low reliability of pin rows of a scraper conveyor and the corresponding support mechanism of a shearer. Simulations were performed using the experimental roller load as stimulus. Results of the analysis demonstrate that the vertical cutting force on the roller serves to reduce the load on the plane support plates during shearer cutting, and the force on the right plane support plate is considerably smaller compared to that on the left plane support plate along the direction of motion of the shearer. Owing to action of the roller-traction load, loads acting on the two guiding support plates increase significantly along the direction of shearer motion. Mechanical characteristics of the support mechanism were determined through experiments, and the accuracy of the virtual simulation model was verified. Simultaneously, mechanical characteristics of the shearer support mechanism were studied under varying pitch and roll angles. This study was performed to provide a base for analyzing the mechanical characteristics as well as optimizing the structural design of the shearer. Through fatigue-life analysis of the support plate and subsequent optimization of the support plate structure, the life of the guide support plate was found to have been extended by approximately 1.5 times.
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Chanmalai, Thanin, Byungik Chang, Kevin Misaro, Saron Hagos, and Thippesh Bethur Hanumanthareddy. "Development of a nomogram to predict the contact stress between an I-girder and a support roller." Engineering Solid Mechanics 9, no. 4 (2021): 377–90. http://dx.doi.org/10.5267/j.esm.2021.7.001.
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The incremental launching method (ILM) is an efficient method of bridge construction primarily suited for environmentally sensitive areas. However, during the bridge launching, there are significant contact stresses between the launching system and the steel bridge girders. These substantial contact stresses can cause damage both on, and just under, the girder surface. Although Hertz contact theory solutions may give an insight into the problem, the accuracy is uncertain due to the presence of complex geometries, loads, and material properties. The complicated structural systems need to rely on numerical modeling such as the finite element analysis which are not always available. The primary objective of this study is to estimate the relationship of the maximum contact stress between an I-girder and a roller using a nomogram. The nomogram is built based on a parametric study with various roller dimensions and loads by numerical modeling. The maximum contact stress from the nomogram can be a useful tool in designing a bridge girder on a support roller.
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Fan, Xiao-bin, Yong Zang, Yuan-kui Sun, and Ping-an Wang. "Impact Analysis of Roller System Stability for Four-High Mill Horizontal Vibration." Shock and Vibration 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/5693584.
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In order to study the hot Compact Strip Production (CSP), four-high mill vibration characteristics, and vibration suppression method, the roller system structure stability was analyzed and calculated at first in the paper. And then, the mill stand gap was measured at field and its influence on roll transverse vibration was analyzed. The drum gear coupling effect on the roller system stability and the automatic balance conditions of the coupling transmission torque were studied; the influence of axial force caused by the roller cross on the system stability was analyzed. Finally, the roller transverse friction chatter vibration mechanics model was established; the simulation analysis was carried out with eliminating mill house-bearing clearance and adding floating support for coupling, respectively. And the characteristics of the roller “jump vibration” were studied. We applied copper gaskets to eliminate or reduce mill house-bearing clearance for suppressing the rolling mill vibration on the spot; the test results show that the roller transverse vibration was suppressed after eliminating clearance.
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Tuladhar, Raju, and Walter H. Dilger. "Effect of support conditions on seismic response of cable-stayed bridges." Canadian Journal of Civil Engineering 26, no. 5 (October 1, 1999): 631–45. http://dx.doi.org/10.1139/l99-021.
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The seismic response of a cable-stayed bridge is the result of the interaction between the input earthquake characteristics and the bridge properties like mass, stiffness, and support conditions. The support type used for the deck at the towers of cable-stayed bridges is one of the important parameters that greatly influences the seismic response of the bridge. This is demonstrated in the present paper by study of the change in modal characteristics and seismic response of two cable-stayed bridges for different types of the support conditions. The first bridge has concrete towers and a steel deck with a 371 m main span, and the second bridge also has concrete towers, but a composite deck with a 465 m main span. The study shows that elastic supports for the deck at the towers give very low deck displacements and deck bending moments compared to pinned or fixed connections. Roller supports produce low tower base shear and base moment but not necessarily a low response for the bridge as a whole. Roller supports also cause the bridge to have very low first longitudinal direction mode frequency; this indicates that the bridge is very flexible in the longitudinal direction. A study of the effect of variation of the longitudinal stiffness of the elastic deck supports shows that it strongly influences the first few longitudinal direction modes, but not the symmetric or higher modes. The study also shows that the seismic response of the bridge is highly influenced by the variation of the support stiffness for some earthquakes like 1940 El Centro earthquake, but to a lesser degree for others. Wave propagation effects were also studied for different support conditions of the bridge. It is observed that the seismic response shows a higher degree of variation with the changing wave velocities when the bridge deck has pinned or fixed supports, and that the change in the bridge response with the wave velocities is not very pronounced when the bridge deck has elastic or roller supports. For the first bridge, the critical responses were observed at very low wave velocities, and for the second bridge, the uniform motion case caused the critical response of the bridge at many locations.Key words: cable-stayed bridges, support conditions, seismic response, wave propagations.
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Sazambayeva Bayan Tokushevna,, Samogin Yuriy Nikolaevich,, Togizbayeva Baglan Bolsinovna,, Kassymbekov Zhuzbay Kozhabayevich,, Makhanov Mukhtar,, Dzhundibayev Valeriy Ermekbayevich,, and Kinzhebayeva Aizhan Serikovna,. "IN REFERENCE TO THE RESEARCH OF PIPE BELT CONVEYOR." BULLETIN 6, no. 388 (December 15, 2020): 19–27. http://dx.doi.org/10.32014/2020.2518-1467.178.
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The article considers the initial provisions of the research and design of conveyor transport that allows to transport bulk cargo in safety. At the same time, it is noted that there is a need for a harmless impact on the environment, especially in long-distance routes transporting with vertical and horizontal bends, as well as with a minimum number of reloading nodes. The review and analysis of the standard sizes of existing conveyors shows certain advantages of the technological nature of the pipe belt conveyor (PBC). The considered construction of PBC, in comparison with existing ones is formed with a closed belt tray due to support devices placed along the perimeter of the transportation line of bulk cargo. It is indicated that when the belt with the load moves simultaneously behind the roller support, due to some collapse of the belt the relationship between the cargo particles and the belt decreases and the system "transported cargo – conveyor belt" is in an active stress state. This circumstance makes it possible to ignore the active phase at high transport speeds. It is revealed that the main advantages of conveyor transport are a high level of labor productivity, achieved by automating the operation of equipment and low production costs. The problems are the need to split the transported cargo, accurate reconciliation of transition areas, coordination of drives and synchronization of movements, easily adjustable in the course of work, subject to certain initial construction conditions. The tractive calculation of the PBC by circumventing the contour, as with traditional conveyors, allowed us to determine the force of resistance to the movement of the belt, the load pressure along the cross section, and the forces acting on the lower and side rollers. A computer 3D model of the PBC was created by using the SolidWorks software product, which includes: creating special support elements and roller supports that twist the belt into the pipe, selecting metal construction elements and calculating their strength, roller supports, and supporting conveyor devices. The stress-strain state of the belt is shown and a model of the PBC under load is constructed, a load map that allows analyzing the distribution of various internal reactive force factors, i.e. forces and moments that occur in the elements of the design model.
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Scullion, Jane, and Cathy Bulley. "Taking a Health Perspective on Roller Derby: A Qualitative Exploration of Women’s Experiences." Women 2, no. 1 (January 20, 2022): 15–28. http://dx.doi.org/10.3390/women2010002.
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Although far fewer women exercise regularly than men, one women-dominated sport growing in popularity internationally is roller derby. A limited number of predominantly US-based and qualitative studies have explored roller derby. This Scotland-based qualitative study explored reasons for women starting, continuing, and stopping participation in roller derby in order to inform people involved in promoting physical activity for health benefits. Semi-structured interviews with six participants from a Scottish women’s roller derby league were recorded and transcribed verbatim. Data analysis using Interpretative Phenomenological Analysis generated five super-ordinate themes. Most participants learned about roller derby from watching the sport on film, attending a bout (game), or word of mouth. The main motivators and benefits of participating in this sport were found to be challenge, enjoyment, increased confidence, health benefits, and motivation to exercise. Participants were empowered by involvement and motivated by community, team spirit, and support to develop. Despite high commitment, some women could not sustain team involvement due to barriers such as injury, changing life roles, and conflicting commitments—a lack of support was described when this happened. Greater inclusivity is needed to enable changing levels of participation as women’s commitments change, to facilitate ongoing health benefits and inspire others.
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Woo, Seongwoo, Dennis L. O’Neal, and Yimer Mohammed Hassen. "Process to Establish the Enhance of Fatigue Life of New Mechanical System Such as a Drawer by Accelerated Tests." Applied Sciences 12, no. 9 (April 28, 2022): 4497. http://dx.doi.org/10.3390/app12094497.
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To extend the life of a mechanical system, parametric Accelerated Life Testing (ALT) is proposed as a procedure to identify design faults and reduce fatigue failure. It includes a derivation of generalized time to failure model by linear transport process and a sample size equation for the ALT. A refrigerator drawer was used as an example. After loading, the rail rollers broke and the center support was bent. Ribs were added to the center support and the rail roller support was extended. At the first ALT, the box cover failed near the intersection between the cover and body. The box was then modified by increasing the rib and fillet. At the second ALT, the rails and center support fractured. They were altered by increasing the rib and corner rounding. After the third ALT, there were no issues. The drawer lifetime was ensured to be B1 life 10 years.
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Yu, Ming Jin, Feng Ping Cao, Tong Qiang Xu, and Xu Yun Qiu. "Study on the Wheel Load Variation Simulation Method of Automobile ABS Performance Test Bench." Advanced Materials Research 479-481 (February 2012): 1433–37. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.1433.
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A method of wheel load variation simulation for automobile ABS performance test bench is presented in the paper. To simulate the wheel load variation of the detected vehicle, the wheel placement angle on the rollers can be changed by adjusting the wheelbase between the ABS performance test bench’s two rollers, which support the same wheel. Equivalent wheel load is defined to reflect wheel load variation simulation, and the relationship among the equivalent wheel load, roller adhesion coefficient and wheel placement angle is also be analyzed. The simulation results show that the equivalent wheel load is not only can greater than wheel load many times, but also can less than wheel load. The minimum equivalent wheel load is determined by the critical wheel placement angle.
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Smirnov, Andrii, and Tamara Mishchenko. "Determination of the loads on the rollers of the tubular belt conveyor." E3S Web of Conferences 109 (2019): 00096. http://dx.doi.org/10.1051/e3sconf/201910900096.
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The article presents methods for determining loads on rollers of a six-roll support of a tubular belt conveyor, based on the equilibrium laws of elastic cylindrical plates and shells filled with a freight. In this case, the forces acting on the rollers of the tubular conveyor are the sum of the forces caused by the weight and expansion of the bulk load, the weight and bend of the belt, as well as the inertial forces associated with the curvature and the deflection of the belt under the weight of the bulk load. The dynamic forces acting on the rollers as the belt moves are determined from the equation of the oscillations of a heavy flexible string using the Ritz method. As a result of the research, analytical dependences of the forces acting on the rollers of the six-roller support of the tubular conveyor on the parameters of the conveyor, the belt, the properties of the bulk load and the radius of curvature of the conveyor are obtained, and an assessment of the component these forces is given. The results can be used to determine the parameters of the tubular conveyors rollers and increase the service life of the rollers.
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Pandit, D., and S. M. Srinivasan. "Large Elasto-plastic Deflection of Thin Beams with Roller Support Contact." Procedia Engineering 173 (2017): 1079–84. http://dx.doi.org/10.1016/j.proeng.2016.12.188.
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Xu, Yun Jie. "Fault Diagnosis for Rolling Bearing Based on Genetic-SVM Classifier." Advanced Materials Research 199-200 (February 2011): 620–24. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.620.
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Fault diagnosis of roller bearings is very complex, so it is difficult to use the mathematical model to describe their faults. Whose developmental changes have dual trends of increase and fluctuation. In this study, support vector machine trained by genetic algorithm based on high frequency demodulation analysis is proposed to fault diagnosis of ball bearing. Genetic algorithm is used to determine training parameters of support vector machine in this model, which can optimize the support vector machine (SVM) an intelligent diagnostic model. The performance of the GSVM system proposed in this study is evaluated by roller bearings in the wood-wool production device. The experimental results indicate that the proposed support vector machine trained by genetic algorithm has good diagnosis results in the application.
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Ghalamchi, Behnam, Jussi Sopanen, and Aki Mikkola. "Simple and Versatile Dynamic Model of Spherical Roller Bearing." International Journal of Rotating Machinery 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/567542.
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Rolling element bearings are essential components of rotating machinery. The spherical roller bearing (SRB) is one variant witnessing increasing use because it is self-aligning and can support high loads. It is becoming increasingly important to understand how the SRB responds dynamically under a variety of conditions. This study introduces a computationally efficient, three-degree-of-freedom, SRB model that was developed to predict the transient dynamic behaviors of a rotor-SRB system. In the model, bearing forces and deflections were calculated as a function of contact deformation and bearing geometry parameters according to the nonlinear Hertzian contact theory. The results reveal how some of the more important parameters, such as diametral clearance, the number of rollers, and osculation number, influence ultimate bearing performance. One pair of calculations looked at bearing displacement with respect to time for two separate arrangements of the caged side-by-side roller arrays, when they are aligned and when they are staggered. As theory suggests, significantly lower displacement variations were predicted for the staggered arrangement. Following model verification, a numerical simulation was carried out successfully for a full rotor-bearing system to demonstrate the application of this newly developed SRB model in a typical real world analysis.
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Qiao, Guan, Geng Liu, Shangjun Ma, Zhenghong Shi, Yawen Wang, and Teik C. Lim. "An improved thermal estimation model of the inverted planetary roller screw mechanism." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 23 (March 27, 2018): 4430–46. http://dx.doi.org/10.1177/0954406218762961.
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The inverted planetary roller screw mechanism has recently become competitive in the electro-mechanical actuation system due to its high load-carrying capacity and small assembly size. However, a significant amount of heat at the frictional contact interfaces and power loss inside the electrical machine can be naturally generated in a compact and high-load inverted planetary roller screw mechanism system. The conductive heat leads to the temperature rise of inverted planetary roller screw mechanism components that subsequently results in thermal drift and error as well as the actuation accuracy degradation. An analytical approach is applied to calculate the friction torque of the contact pairs and support bearings in the inverted planetary roller screw mechanism system. As the thermal load, heat generation is derived from the friction in nut-roller-screw section and bearings. Then, the heat generation and convection boundary conditions are formulated to facilitate thermal behavior analysis. Finally, using the finite element method, steady-state and transient thermal-mechanical coupling analyses are performed to estimate the temperature distribution and thermal expansion of the inverted planetary roller screw mechanism components. Computational results reveal that operating conditions of rotation speed and external load have significant influence on the thermal characteristics of the inverted planetary roller screw mechanism. This study can serve as a foundation for modeling temperature field and analyzing coupled thermal-mechanical response of inverted planetary roller screw mechanism in electro-mechanical actuation system, which can be useful in determining thermal error compensation.
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Pan, Rui, Tao Xu, and Yong Liu. "The Fault Diagnosis Method for Roller Bearing with Harmonic Wavelet Packet and DT-SVM." Applied Mechanics and Materials 724 (January 2015): 238–41. http://dx.doi.org/10.4028/www.scientific.net/amm.724.238.
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This paper studies the roller bearing fault diagnosis method with harmonic wavelet packet and Decision Tree-Support Vector Machine (DT-SVM). The harmonic wavelet packet possesses better performances for its box-shaped spectrum and unlimited subdivision compared with the conventional time-frequency feature exaction method. Firstly, the proposed method decomposes the roller bearing vibration signal with harmonic wavelet packet and extracts the feature energy with coefficients of each spectrum. After the feature energy is normalized, feature vector are available. Based on multi-level binary tree, this paper designs the multi-classification SVM model due to its superior nonlinear mapping capability. Three two-classifications are incorporated to diagnosis the roller bearing faults. Finally, the proposed method is illustrated with the vibration data from the roller bearing stand of electric engineering lab in case western reserve university. Experimental results illustrate the higher accuracy of the proposed method compared with conventional method.
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Vedishchev, Sergey, A. Brusenkov, N. Milyukov, M. Garina, and V. Sorokin. "Designing of the device with a roller support for grinding root crops." Актуальные направления научных исследований XXI века: теория и практика 3, no. 1 (August 13, 2015): 125–29. http://dx.doi.org/10.12737/10611.
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Nezic, A., Aleksandar Knezevic, Milan Cirkovic, Predrag Milojevic, Miroslav Jakovljevic, and S. Jagodic. "Postcardiotomy assisted circulation with roller pump-early and late results." Acta chirurgica Iugoslavica 50, no. 4 (2003): 69–71. http://dx.doi.org/10.2298/aci0304069n.
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The incidence of postcardiotomy myocardial failure (PMF) requiring mechanical circulatory support beyond IABP is reported to be 0.2% to 1.2%. From Dec. 1989 through Dec. 1995, 18 patients (0.3% of the total pump cases) were supported with roller pump type of LVAD. Assisted flow ranged from 3.5 up to 5 L/min with average support time of 35.5 hours. Six (33.3%) patients (pts) died while on LVAD. The causes of additional seven deaths (pts weaned of LVAD) were: myocardial failure (4), stroke (2) and intractable bleeding during removal of the LVAD (1). Overall, five patients (27.8 %) were successfully discharged from the hospital. Two out of five long-term survivors died later, 6 months and 4 years postoperatively, both of cardiac causes. The actuarial survival rate of long-term survivors was 60% at 7 years, all of them being in NYHA functional class II. These results have proved efficiency of roller pump driven LVAD for short-term circulatory support in pts with PMF. Results are comparable to so far published data on postcardiotomy support with the same, as well as other types of more versatile and costly devices.
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Soejima, Mitsuhiro, Yuki Matsushita, and Shingo Sakaguchi. "2309 Study on Friction Loss in Valve Train with Cam and Roller Follower : Influences of Roller Support Bearing and Engine Oil." Proceedings of the JSME annual meeting 2008.3 (2008): 67–68. http://dx.doi.org/10.1299/jsmemecjo.2008.3.0_67.
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Simonis, Andreas, and Christian Schindler. "Measuring the wheel-rail forces of a roller coaster." Journal of Sensors and Sensor Systems 7, no. 2 (September 10, 2018): 469–79. http://dx.doi.org/10.5194/jsss-7-469-2018.
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Abstract. During a roller coaster ride, the vehicles and their passengers are exposed to multiple times the acceleration of earth's gravity. The corresponding forces must be transmitted by the wheels to the track and the support structure. To validate the load assumptions of static and fatigue analysis, it is necessary to measure these forces. Currently, it is deemed sufficient to measure only the accelerations, providing a limited view of the whole. This article presents a method to measure the actual forces and moments that act on a wheel. Since the diameters of roller coaster wheels are comparatively small (approx. 200 mm) and the loads high (approx. 30 kN), industrially available multi-axis transducers cannot be used. Therefore, a transducer design based on strain gauges was developed and successfully implemented in a roller coaster vehicle. Due to its scalability, its application is not limited to just roller coaster wheels: it can be used for all types of non-driven wheels as well.
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Li, Xin rong, LiuBo Wu, Zhaoning Bu, and Lidong Liu. "Predicting the number of fiber roots in lola drafting based on multi-field coupling." Textile Research Journal 90, no. 23-24 (June 6, 2020): 2769–81. http://dx.doi.org/10.1177/0040517520930192.
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Pullout theory is very important in improving efficiency, quality, and production costs. Because production efficiency is too low for mechanical drafting equipment, a simple multi-field coupling model of fiber mechanics based on conserving momentum is proposed that considers the distribution of the fiber speed point, slip rate, and friction mechanics. When the roller draft multiple is increased, the position near the rear roller clamp mouth in the draft area will show a sharp decrease of fiber, which is caused by the rapid movement of the front fiber to drive the floating fiber movement, and it is also the existence of the fiber change point. When the roller spacing increases, the draft efficiency decreases, although the pressure applied by the roller to the fibrous strip has a weak effect on the draft efficiency. This research increases our understanding of drawing and provides theoretical support for the design of a new type of drawing.