The Effect of Force Level Condition before Controlling on the Characteristics of Grading

The integrity of tube bundles is very important especially when dealing with high-risk applications such as nuclear steam generators. A major issue to system integrity is the flow-induced vibration (FIV). FIV is manifested through several mechanisms including the most severe mechanism; fluidelastic instability (FEI). Tube vibration can be constrained by using tube supports. However, clearances between the tube and their support are required to allow for thermal expansion and for other manufacturing considerations. The clearance between tubes may allow frequent impact and friction between tube and support. This in turn may cause fatigue and wear at support and potential for catastrophic tube failure. This study aims to investigate the dynamics of loosely supported tube array subjected to cross-flow. The work is performed experimentally in an open-loop wind tunnel to address this issue. A loosely-supported single flexible tube in both triangle and square arrays subjected to cross-flow with a pitch-to-diameter ratio of 1.5 and 1.733, respectively were considered. The effect of the flow approach angle, as well as the support clearance on the tube response, are investigated. In addition, the parameters that affect tube wear such as impact force level are presented.

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Neuronal mechanisms underlying physiological tremor

Journal of Neurophysiology ◽

10.1152/jn.1978.41.3.557 ◽

1978 ◽

Vol 41 (3) ◽

pp. 557-571 ◽

Cited By ~ 243

Author(s):

J. H. Allum ◽

V. Dietz ◽

H. J. Freund

Keyword(s):

Power Spectrum ◽

Pathological Condition ◽

Power Spectra ◽

Motor Units ◽

Physiological Tremor ◽

Force Level ◽

Force Output ◽

Experimental Conditions ◽

Single Motor Unit ◽

Total Fusion

1. Tremor force was recorded during stationary isometric contractions of intrinsic hand muscles of normal subjects. Subjects maintained a steady force level between their thumb and forefinger for 30 s. The force level varied from weak (0.2 kg) to strong contractions (7 kg). These experimental conditions were the same as those in two preceding studies, where single motor-unit activity (14) and the correlation between the discharges of two simultaneously recorded motor units and physiological tremor (11) have been investigated. 2. Two alterations of the power spectra were observed at successively stronger contractions: increase of tremor amplitude and changes in the shape of the power spectrum. At all force levels, the power spectra of tremor force show the well-known decay of tremor amplitude from the lower to the higher frequencies with a local peak at 6--10 Hz. This peak does not show a significant change with respect to frequency when the force level is varied. It is shifted toward lower frequencies in a pathological condition (Parkinsonism) where the recruitment firing rates of the motor units are significantly lower than in the normal. 3. Higher frequencies (greater than 20 Hz) are barely present in the power spectrum during the very weak contractions. They become significant as the contractions become stronger. 4. The steep decay of the power spectrum toward higher frequencies has a similar slope (--43 dB/decade) as the reduction in amplitude of the unfused part of the muscle contractions with increasing stimulus rates (--38 dB/decade). The cutoff of the power spectrum above 25 Hz parallels the achievement of total fusion of muscle twitches above this rate. 5. The results are consistent with the hypothesis that the power spectrum over the range of 6--25 Hz is mainly caused by the unfused parts of the twitch contractions of motor units firing between recruitment (6--8/s) and total fusion of the twitches (25--30/s). The decline of the power spectrum toward higher frequencies can be explained by mechanical damping, which results from increasing fusion of the twitch contractions. The low-frequency part of the power spectrum is assumed to be the result of the slow force deviations produced by changes in the net output of the motoneuron pool. 6. These assumptions were supported by additional animal experiments where the number and rate of force-producing elements could be controlled. Bundles of ventral root filaments innervating cat soleus and gastrocnemius muscles were stimulated synchronously and asynchronously at a number of different rates. The force output of the strain gauge was recorded, filtered, and analyzed in the same way as the human force records. 7. Stimualtion of one nerve bundle at one fixed frequency led to a sharp peak in the power spectrum at that frequency plus peaks of decreasing height representing the harmonics of the stimulation frequency. The height of the peaks decreased at --37 dB/decade. 8...

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The Influence of Force Level and Motor Unit Coherence on Nonlinear Surface EMG Features Examined Using Model Simulation

2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) ◽

10.1109/embc.2019.8857299 ◽

2019 ◽

Author(s):

Lara McManus ◽

Diego Pereira Botelho ◽

Matthew W. Flood ◽

Madeleine M. Lowery

Keyword(s):

Motor Unit ◽

Model Simulation ◽

Surface Emg ◽

Force Level ◽

Nonlinear Surface

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Computer Simulation of Female Urinary Incontinence

Journal of Medical Devices ◽

10.1115/1.2932448 ◽

2008 ◽

Vol 2 (2) ◽

Author(s):

Yingchun Zhang ◽

Gerald W. Timm ◽

Arthur G. Erdman

Keyword(s):

Finite Element ◽

Urinary Incontinence ◽

Finite Element Model ◽

Element Model ◽

Physical Activities ◽

Sample Population ◽

Force Level ◽

Female Pelvis ◽

Tissue Properties ◽

Mechanical Tissue

Objectives: The purpose of this study is to establish pressure, distension and other parameters involved that produce tissue injury during vigorous physical activities in women, so that superior methods and devices for diagnosing and treating urinary incontinence (UI) can be created. Background: A higher prevalence of daily UI in a female athlete population was found compared to that of a randomly selected and age matched sample population, but the mechanism of UI is not clearly understood. Methods: Mechanical tissue properties of affected organ structures were determined by using specimens from cadavers. A realistic geometric model of the female pelvis was developed from patients’ specific CT images. The finite element model was built by combining the mechanical tissue properties and the geometry of organs involved, and the finite element analysis (FEA) was then performed using ABAQUS 6.7 to simulate the biomechanical response of the female pelvis during physical activities. Results: Tissue specimens from 11 cadavers were tested which included specimens of the bladder, uterus, pelvic muscle, vagina and urethra. A finite element model was built with approximately 500,000 tetrahedral elements. The force level and resulting organ displacements in the female pelvis during physical activities were investigated successfully by using the FEA method. Discussion: The knowledge of force level and organ displacements during physical activities helps to understand the mechanisms of UI occurring during physical activities.

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High Three-Dimensional Detection Accuracy in Piezoelectric-Based Touch Panel in Interactive Displays by Optimized Artificial Neural Networks

Sensors ◽

10.3390/s19040753 ◽

2019 ◽

Vol 19 (4) ◽

pp. 753 ◽

Cited By ~ 4

Author(s):

Shuo Gao ◽

Yanning Dai ◽

Vasileios Kitsos ◽

Bo Wan ◽

Xiaolei Qu

Keyword(s):

Neural Networks ◽

Artificial Neural Networks ◽

Computational Cost ◽

Machine Learning Algorithms ◽

Smart Device ◽

Detection Accuracy ◽

Force Level ◽

High Detection ◽

Artificial Neural ◽

Interactive Displays

High detection accuracy in piezoelectric-based force sensing in interactive displays has gained global attention. To achieve this, artificial neural networks (ANN)—successful and widely used machine learning algorithms—have been demonstrated to be potentially powerful tools, providing acceptable location detection accuracy of 95.2% and force level recognition of 93.3% in a previous study. While these values might be acceptable for conventional operations, e.g., opening a folder, they must be boosted for applications where intensive operations are performed. Furthermore, the relatively high computational cost reported prevents the popularity of ANN-based techniques in conventional artificial intelligence (AI) chip-free end-terminals. In this article, an ANN is designed and optimized for piezoelectric-based touch panels in interactive displays for the first time. The presented technique experimentally allows a conventional smart device to work smoothly with a high detection accuracy of above 97% for both location and force level detection with a low computational cost, thereby advancing the user experience, and serviced by piezoelectric-based touch interfaces in displays.

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A STUDY OF MODELS FOR HANDGRIP FORCE PREDICTION FROM SURFACE ELECTROMYOGRAPHY OF EXTENSOR MUSCLE

Biomedical Engineering Applications Basis and Communications ◽

10.4015/s1016237209001131 ◽

2009 ◽

Vol 21 (02) ◽

pp. 81-88 ◽

Cited By ~ 1

Author(s):

Wensheng Hou ◽

Xiaolin Zheng ◽

Yingtao Jiang ◽

Jun Zheng ◽

Chenglin Peng ◽

...

Keyword(s):

Root Mean Square ◽

Surface Electromyography ◽

Random Sequence ◽

Maximum Voluntary Contraction ◽

Force Production ◽

Voluntary Contraction ◽

Mean Square ◽

Force Level ◽

Force Output ◽

Mean Square Errors

Force production involves the coordination of multiple muscles, and the produced force levels can be attributed to the electrophysiology activities of those related muscles. This study is designed to explore the activity modes of extensor carpi radialis longus (ECRL) using surface electromyography (sEMG) at the presence of different handgrip force levels. We attempt to compare the performance of both the linear and nonlinear models for estimating handgrip forces. To achieve this goal, a pseudo-random sequence of handgrip tasks with well controlled force ranges is defined for calibration. Eight subjects (all university students, five males, and three females) have been recruited to conduct both calibration and voluntary trials. In each trial, sEMG signals have been acquired and preprocessed with Root–Mean–Square (RMS) method. The preprocessed signals are then normalized with amplitude value of Maximum Voluntary Contraction (MVC)-related sEMG. With the sEMG data from calibration trials, three models, Linear, Power, and Logarithmic, are developed to correlate the handgrip force output with the sEMG activities of ECRL. These three models are subsequently employed to estimate the handgrip force production of voluntary trials. For different models, the Root–Mean–Square–Errors (RMSEs) of the estimated force output for all the voluntary trials are statistically compared in different force ranges. The results show that the three models have different performance in different force ranges. Linear model is suitable for moderate force level (30%–50% MVC), whereas a nonlinear model is more accurate in the weak force level (Power model, 10%–30% MVC) or the strong force level (Logarithmic model, 50%–80% MVC).

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Afferent Contributions to Digit Force Coupling and Force Level Variation During Performance of Non-lift Pinch

Neurocase ◽

10.1080/13554790601126039 ◽

2006 ◽

Vol 12 (5) ◽

pp. 300-306 ◽

Cited By ~ 1

Author(s):

Victoria A. Moerchen ◽

Kreg G. Gruben

Keyword(s):

Force Level ◽

Level Variation ◽

Force Coupling

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VESTIBULAR AFFERENTS POPULATION ACTIVATED BY VARIOUS MODES FOR ELICITING OCULAR AND CERVICAL VESTIBULAR-EVOKED MYOGENIC POTENTIALS

Biomedical Engineering Applications Basis and Communications ◽

10.4015/s1016237211002864 ◽

2011 ◽

Vol 23 (06) ◽

pp. 527-532 ◽

Cited By ~ 1

Author(s):

Shou-Jen Wang ◽

Fu-Shan Jaw ◽

Yi-Ho Young

Keyword(s):

Healthy Subjects ◽

Mean Amplitude ◽

Vestibular Evoked Myogenic Potentials ◽

Force Level ◽

Characteristic Parameters ◽

Stimulation Mode ◽

Vestibular Afferents ◽

Significant Difference ◽

The Mean

This study compared cervical and ocular vestibular-evoked myogenic potentials (cVEMPs and oVEMPs) between air-conducted sound (ACS) and bone-conducted vibration (BCV) modes to determine whether these two stimulation modes activate the same population of primary vestibular afferents. Fifteen healthy subjects underwent cVEMP and oVEMP tests using ACS stimuli at 127 dB pe SPL and BCV stimuli at 128 dB force level. The characteristic parameters of cVEMPs and oVEMPs were compared between ACS and BCV modes. The mean p13 and n23 latencies of ACS-cVEMPs were significantly longer than those of BCV-cVEMPs. Likewise, the mean nI and pI latencies for ACS-oVEMPs were also significantly longer than those for BCV-oVEMPs. There was no significant difference in the mean amplitude of cVEMPs between the ACS and BCV modes. However, comparing the oVEMP amplitude, a relationship: (Amplitude of BCV-oVEMP) = 2.3 x (Amplitude of ACS-oVEMP) was demonstrated. In conclusion, the population of primary vestibular afferents activated by ACS and BCV stimuli is similar for cVEMPs. In contrast with oVEMPs, BCV mode activates more number of primary vestibular afferents than ACS mode does. In interpreting oVEMP and cVEMP results, stimulation mode should be checked first.

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