scholarly journals Effect of Handrail Height and Age on Trunk and Shoulder Kinematics Following Perturbation-Evoked Grasping Reactions During Gait

2021 ◽  
pp. 001872082110136
Author(s):  
Vicki Komisar ◽  
Alison C. Novak
Keyword(s):  
Angular Displacement ◽  
Unintentional Injury ◽  
Workplace Safety ◽  
Contact Forces ◽  
Balance Recovery ◽  
Safety Standards ◽  
Angular Displacements ◽  
Shoulder Kinematics ◽  
And Control ◽  
Balance Loss

Objective To characterize the effect of handrail height and age on trunk and shoulder kinematics, and concomitant handrail forces, on balance recovery reactions during gait. Background Falls are the leading cause of unintentional injury in adults in North America. Handrails can significantly enhance balance recovery and help individuals to avoid falls, provided that their design allows users across the lifespan to reach and grasp the rail after balance loss, and control their trunk by applying hand-contact forces to the rail. However, the effect of handrail height and age on trunk and shoulder kinematics when recovering from perturbations during gait is unknown. Method Fourteen younger and 13 older adults experienced balance loss (sudden platform translations) while walking beside a height-adjustable handrail. Handrail height was varied from 30 to 44 inches (76 to 112 cm). Trunk and shoulder kinematics were measured via 3D motion capture; applied handrail forces were collected from load cells mounted to the rail. Results As handrail height increased (up to 42 inches/107 cm), peak trunk angular displacement and velocity generally decreased, while shoulder elevation angles during reaching and peak handrail forces did not differ significantly between 36 and 42 inches (91 and 107 cm). Age was associated with reduced peak trunk angular displacements, but did not affect applied handrail forces. Conclusion Higher handrails (up to 42 inches) may be advantageous for trunk control when recovering from destabilizations during gait. Application Our results can inform building codes, workplace safety standards, and accessibility standards, for safer handrail design.

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

Experimental Investigation on the Rubbing Process of Labyrinth Seals Considering the Material Combination

2020 ◽  
Author(s):  
Lisa Hühn ◽  
Oliver Munz ◽  
Corina Schwitzke ◽  
Hans-Jörg Bauer
Keyword(s):  
Turbine Blades ◽  
Design Guidelines ◽  
Operating Conditions ◽  
Contact Forces ◽  
Experimental Investigations ◽  
Process Data ◽  
Labyrinth Seals ◽  
Material Combination ◽  
Higher Temperature ◽  
And Control

Abstract Labyrinth seals are used to prevent and control the mass flow rate between rotating components. Due to thermally and mechanically induced expansions during operation and transient flight maneuvers, a contact, the so-called rubbing process, between rotor and stator cannot be excluded. A large amount of rubbing process data concerning numerical and experimental investigations is available in public literature as well as at the Institute of Thermal Turbomachinery (ITS). The investigations were carried out for different operating conditions, material combinations, and component geometries. In combination with the experiments presented in this paper, the effects of the different variables on load due to rubbing are compared, and discussed with the focus lying on the material combination. The influence of the material on the loads can be identified as detailed as never before. For example, the contact forces in the current experiments are higher due to a higher temperature resistance of Young’s modulus. The analysis will also be based on the rubbing of turbine blades. Design guidelines are derived for labyrinth seals with improved properties regarding tolerance of rub events. Based on the knowledge obtained, guidelines for designing reliable labyrinth seals for future engines are discussed.

Ensuring social guarantees and human rights for the implementation of the labour legislation of the Republic of Kazakhstan

2020 ◽  
pp. 315-335
Author(s):  
Anarkhan R. Kuttygalieva ◽  
Yermek A. Buribayev ◽  
Bakhytkali M. Koshpenbetov ◽  
Gakku N. Rakhimova ◽  
Zhanna A. Khamzina ◽  
...  
Keyword(s):  
Human Rights ◽  
Labour Market ◽  
Analytical Method ◽  
Practical Significance ◽  
Safety Standards ◽  
Collective Agreements ◽  
The Republic ◽  
Labour Legislation ◽  
And Control ◽  
Labour Regulation

The relevance of the study is determined by the fact that in order to improve the legislation of the country, it is necessary to study the successful experience of other countries. The purpose of the study is to propose a number of measures that will help improve labour legislation in Kazakhstan. The work uses primarily the analytical method. It is determined by the fact that apart from statutory labour protection rules, some safety standards are contained in collective agreements that speci-fy and sometimes supplement relevant legislative provisions. The paper states the fact that it is necessary to factor in world experience in organizing and operating a system of supervision and control over compliance with labour legislation for the Republic of Kazakhstan. The novelty of the study is that with a study of the legislation on labour regulation in Western countries, the authors identify a number of measures that will be relevant for implementation in the Republic of Kazakhstan. The practical significance of the study is determined by the incompatibility of iso-lation from the outside world, including from the international labour market with objectives of development.

On the Use of Actively Controlled Auxiliary Bearings in Magnetic Bearing Systems

2008 ◽  
Author(s):  
Iain S. Cade ◽  
M. Necip Sahinkaya ◽  
Clifford R. Burrows ◽  
Patrick S. Keogh
Keyword(s):  
Controller Design ◽  
Control Strategies ◽  
Frictional Heating ◽  
Magnetic Bearing ◽  
Contact Forces ◽  
Active Magnetic Bearing ◽  
Physical Limit ◽  
Drop Tests ◽  
Auxiliary Bearing ◽  
And Control

Auxiliary bearings are used to prevent rotor/stator contact in active magnetic bearing systems. They are sacrificial components providing a physical limit on the rotor displacement. During rotor/auxiliary bearing contact significant forces normal to the contact zone may occur. Furthermore, rotor slip and rub can lead to localized frictional heating. Linear control strategies may also become ineffective or induce instability due to changes in rotordynamic characteristics during contact periods. This work considers the concept of using actively controlled auxiliary bearings in magnetic bearing systems. Auxiliary bearing controller design is focused on attenuating bearing vibration resulting from contact and reducing the contact forces. Controller optimization is based on the H∞ norm with appropriate weighting functions applied to the error and control signals. The controller is assessed using a simulated rotor/magnetic bearing system. Comparison of the performance of an actively controlled auxiliary bearing is made with that of a resiliently mounted auxiliary bearing. Rotor drop tests, repeated contact tests, and sudden rotor unbalance resulting in trapped contact modes, are considered.

scholarly journals Medical student education for injury prevention: closing the gap

2020 ◽  
pp. injuryprev-2020-043759 ◽  
Author(s):  
Amy Zosel ◽  
Sara Kohlbeck ◽  
Christopher S Davis ◽  
Linda Meurer ◽  
Stephen Hargarten
Keyword(s):  
Public Health ◽  
Injury Prevention ◽  
Prevention And Control ◽  
Unintentional Injury ◽  
Medical Student Education ◽  
School Curriculum ◽  
Public Health Issue ◽  
Public Health Approach ◽  
Main Component ◽  
And Control

IntroductionInjury is a major public health issue in the USA. In 2017, unintentional injury was the leading cause of death for ages 1 through 44. Unfortunately, there is evidence that the sciences of injury prevention and control may not fully and widely integrated into medical school curriculum. This paper describes a novel injury prevention and control summer programme that was implemented in 2002 and is ongoing.MethodsThe main component of the Series includes at least seven injury-related lectures and discussions designed to provoke students’ interest and understanding of injury as a biopsychosocial disease. These lectures are organised in a seminar fashion and are 2–4 hours in duration. Kirkpatrick’s four-part model guides evaluation specific to our four programme objectives. Trainee satisfaction with the programme, knowledge and outcome (specific to career goals) is evaluated using several mixed-methods tools.ResultsA total of 318 students have participated in the Series. Evaluation findings show an increase in knowledge of injury-related concepts as well as an increase in interest in pursuing injury-related research topics in the future.ImplicationsThe Series is a novel and innovative programme that provides training in injury and injury prevention and control-related topics to medical students, as well as undergraduate, graduate and pharmacy students. We hope that by increasing students’ knowledge and understanding of injury prevention and control we are contributing to a physician workforce that understands the importance of a public health approach to injury prevention, that implements public health principles in practice and that advocates for policies and practices that positively impact injury prevention and control to help make our communities healthier and safer.

Design of Measure and Control System of the Ring Block Casing Wear Tester

2013 ◽  
Vol 423-426 ◽  
pp. 2414-2418
Author(s):  
Xiang Tong Yang ◽  
Xiao Zeng Wang ◽  
Yin Ping Cao ◽  
Yi Hua Dou
Keyword(s):  
Control System ◽  
Calibration Method ◽  
Contact Forces ◽  
Wear Depth ◽  
Friction Forces ◽  
Deep Wells ◽  
Geological Conditions ◽  
Casing Wear ◽  
Measure And Control System ◽  
And Control

In deep wells and ultra-deep wells the complex geological conditions often result in serious casing wear. In order to obtain the wear efficiency which is used to compute the wear depth of downhole casing, the ring block drillpipe casing wear tester is developed. The measure and control system which include the measure circuits of contact forces between casing and drillpipe samples, the measure circuits of the friction forces are main component of wear tester. It is very important to design the measure and control system of tester. The paper also develops the calibration method of the loads sensors used to measure the contact and friction force. The wear tester can accurately measure the wear efficiency and the friction coefficient needed by casing wear prediction.

Design and Analysis of a Multimodal Grasper Having Shape Conformity and Within-Hand Manipulation With Adjustable Contact Forces

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Nagamanikandan Govindan ◽  
Asokan Thondiyath
Keyword(s):  
Control Strategies ◽  
Low Cost ◽  
Active Surface ◽  
Force Sensor ◽  
Contact Forces ◽  
Geometrical Shape ◽  
Planning And Control ◽  
Control Scheme ◽  
And Control ◽  
Compact Mechanism

Abstract This paper presents the design, analysis, and testing of a novel multimodal grasper having the capabilities of shape conformation, within-hand manipulation, and a built-in compact mechanism to vary the forces at the contact surface. The proposed grasper has two important qualities: versatility and less complexity. The former refers to the ability to grasp a range of objects having different geometrical shape, size, and payload and perform in-hand manipulations such as rolling and sliding, and the latter refers to the uncomplicated design, and ease of planning and control strategies. Increasing the number of functions performed by the grasper to adapt to a variety of tasks in structured and unstructured environments without increasing the mechanical complexity is the main interest of this research. The proposed grasper consists of two hybrid jaws having a rigid inner structure encompassed by a flexible, active gripping surface. The flexibility of the active surface has been exploited to achieve shape conformation, and the same has been utilized with a compact mechanism, introduced in the jaws, to vary the contact forces while grasping and manipulating an object. Simple and scalable structure, compactness, low cost, and simple control scheme are the main features of the proposed design. Detailed kinematic and static analysis are presented to show the capability of the grasper to adjust and estimate the contact forces without using a force sensor. Experiments are conducted on the fabricated prototype to validate the different modes of operation and to evaluate the advantages of the proposed concept.

Effect of Expertise on Shoulder and Upper Limb Kinematics, Electromyography, and Estimated Muscle Forces During a Lifting Task

2020 ◽  
pp. 001872082096502
Author(s):  
Etienne Goubault ◽  
Romain Martinez ◽  
Najoua Assila ◽  
Élodie Monga-Dubreuil ◽  
Jennifer Dowling-Medley ◽  
...  
Keyword(s):  
Upper Limb ◽  
Glenohumeral Joint ◽  
Contact Forces ◽  
Muscle Forces ◽  
Shoulder Injuries ◽  
Effective Work ◽  
Limb Kinematics ◽  
Manual Handling ◽  
Shoulder Kinematics ◽  
Lifting Task

Objective To highlight the working strategies used by expert manual handlers compared with novice manual handlers, based on recordings of shoulder and upper limb kinematics, electromyography (EMG), and estimated muscle forces during a lifting task. Background Novice workers involved in assembly, manual handling, and personal assistance tasks are at a higher risk of upper limb musculoskeletal disorders (MSDs). However, few studies have investigated the effect of expertise on upper limb exposure during workplace tasks. Method Sixteen experts in manual handling and sixteen novices were equipped with 10 electromyographic electrodes to record shoulder muscle activity during a manual handling task consisting of lifting a box (8 or 12 kg), instrumented with three six-axis force sensors, from hip to eye level. Three-dimensional trunk and upper limb kinematics, hand-to-box contact forces, and EMG were recorded. Then, joint contributions, activation levels, and muscle forces were calculated and compared between groups. Results Sternoclavicular–acromioclavicular joint contributions were higher in experts at the beginning of the movement, and in novices at the end, whereas the opposite was observed for the glenohumeral joint. EMG activation levels were 37% higher for novices but predicted muscle forces were higher in experts. Conclusion This study highlights significant differences between experts and novices in shoulder kinematics, EMG, and muscle forces; hence, providing effective work guidelines to ensure the development of a safe handling strategy is important. Application Shoulder kinematics, EMG, and muscle forces could be used as ergonomic tools to identify inappropriate techniques that could increase the prevalence of shoulder injuries.

scholarly journals BIOMECHANICAL EFFECTS OF HYPERPRONATION ON MULTIDIRECTIONAL ANKLE ANGULAR DISPLACEMENT AND STIFFNESS

2020 ◽  
Vol 20 (09) ◽  
pp. 2040012
Author(s):  
GEON KIM ◽  
JIHEE JUNG ◽  
YOUNGJOO CHA ◽  
JOSHUA (SUNG) H. YOU
Keyword(s):  
Sagittal Plane ◽  
Angular Displacement ◽  
Three Dimensional ◽  
Frontal Plane ◽  
Neutral Group ◽  
Stiffness Reduction ◽  
Ankle Stiffness ◽  
Foot Injury ◽  
Increased Risk ◽  
Angular Displacements

Hyperpronation of the foot is believed to contribute to ankle hypermobility and associated stiffness reduction, but the underlying biomechanical mechanisms remain unknown. This study aimsed to investigate multidirectional ankle displacement and associated stiffness when a posterior–anterior impact force was applied to the posterior knee compartment. Forty healthy adults with and without foot hyperpronation were recruited. A three-dimensional motion capture system and force plates were used to acquire angular displacement and ankle joint moment data. The independent [Formula: see text]-test and Mann–Whitney [Formula: see text] test were used to compare the group differences in ankle angular displacement, moment, and stiffness. Spearman’s rho test was performed to determine the relationship between ankle angular displacement and stiffness. The hyperpronation group demonstrated significantly greater sagittal ([Formula: see text]) and frontal plane ([Formula: see text]) angular displacements and reduced sagittal plane ankle stiffness ([Formula: see text]) than the neutral group. The Spearman’s correlation analysis showed a close inverse relationship between the ankle angular displacement and stiffness, ranging from [Formula: see text] to [Formula: see text]. The biomechanical data in our study suggest that individuals with foot hyperpronation present with multidirectional hypermobility and a reduction in ankle stiffness. These factors contribute to an increased risk of ankle-foot injury in individuals with foot hyperpronation.

scholarly journals Shoulder Kinematics Is Not Influenced by External Load During Elevation in the Scapular Plane

2014 ◽  
Vol 30 (1) ◽  
pp. 66-74 ◽  
Author(s):  
Marcelo P. de Castro ◽  
Daniel Cury Ribeiro ◽  
Felipe de C. Forte ◽  
Joelly M. de Toledo ◽  
Daniela Aldabe ◽  
...  
Keyword(s):  
Repeated Measures ◽  
External Load ◽  
External Rotation ◽  
Angular Displacement ◽  
Neutral Position ◽  
Convenience Sample ◽  
Repeated Measures Design ◽  
Shoulder Kinematics ◽  
Shoulder Elevation ◽  
Scapular Plane

The current study aimed to compare the shoulder kinematics (3D scapular orientation, scapular angular displacement and scapulohumeral rhythm) of asymptomatic participants under unloaded and loaded conditions during unilateral shoulder elevation in the scapular plane. We used a repeated-measures design with a convenience sample. Eleven male participants with an age range of 21–28 years with no recent history of shoulder injury participated in the study. The participants performed isometric shoulder elevation from a neutral position to approximately 150 degrees of elevation in the scapular plane in intervals of approximately 30 degrees during unloaded and loaded conditions. Shoulder kinematic data were obtained with videogrammetry. During shoulder elevation, the scapula rotated upwardly and externally, and tilted posteriorly. The addition of an external load did not affect 3D scapular orientation, scapular angular displacement, or scapulohumeral rhythm throughout shoulder elevation (P> .05). In clinical practice, clinicians should expect to observe upward and external rotation and posterior tilt of the scapula during their assessments of shoulder elevation. Such behavior was not influenced by an external load normalized to 5% of body weight when performed in an asymptomatic population.

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