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Sample records for active joint torques

  1. Space Suit Joint Torque Testing

    NASA Technical Reports Server (NTRS)

    Valish, Dana J.

    2011-01-01

    In 2009 and early 2010, a test was performed to quantify the torque required to manipulate joints in several existing operational and prototype space suits in an effort to develop joint torque requirements appropriate for a new Constellation Program space suit system. The same test method was levied on the Constellation space suit contractors to verify that their suit design meets the requirements. However, because the original test was set up and conducted by a single test operator there was some question as to whether this method was repeatable enough to be considered a standard verification method for Constellation or other future space suits. In order to validate the method itself, a representative subset of the previous test was repeated, using the same information that would be available to space suit contractors, but set up and conducted by someone not familiar with the previous test. The resultant data was compared using graphical and statistical analysis and a variance in torque values for some of the tested joints was apparent. Potential variables that could have affected the data were identified and re-testing was conducted in an attempt to eliminate these variables. The results of the retest will be used to determine if further testing and modification is necessary before the method can be validated.

  2. Space Suit Joint Torque Measurement Method Validation

    NASA Technical Reports Server (NTRS)

    Valish, Dana; Eversley, Karina

    2012-01-01

    In 2009 and early 2010, a test method was developed and performed to quantify the torque required to manipulate joints in several existing operational and prototype space suits. This was done in an effort to develop joint torque requirements appropriate for a new Constellation Program space suit system. The same test method was levied on the Constellation space suit contractors to verify that their suit design met the requirements. However, because the original test was set up and conducted by a single test operator there was some question as to whether this method was repeatable enough to be considered a standard verification method for Constellation or other future development programs. In order to validate the method itself, a representative subset of the previous test was repeated, using the same information that would be available to space suit contractors, but set up and conducted by someone not familiar with the previous test. The resultant data was compared using graphical and statistical analysis; the results indicated a significant variance in values reported for a subset of the re-tested joints. Potential variables that could have affected the data were identified and a third round of testing was conducted in an attempt to eliminate and/or quantify the effects of these variables. The results of the third test effort will be used to determine whether or not the proposed joint torque methodology can be applied to future space suit development contracts.

  3. Ankle and hip postural strategies defined by joint torques

    NASA Technical Reports Server (NTRS)

    Runge, C. F.; Shupert, C. L.; Horak, F. B.; Zajac, F. E.; Peterson, B. W. (Principal Investigator)

    1999-01-01

    Previous studies have identified two discrete strategies for the control of posture in the sagittal plane based on EMG activations, body kinematics, and ground reaction forces. The ankle strategy was characterized by body sway resembling a single-segment-inverted pendulum and was elicited on flat support surfaces. In contrast, the hip strategy was characterized by body sway resembling a double-segment inverted pendulum divided at the hip and was elicited on short or compliant support surfaces. However, biomechanical optimization models have suggested that hip strategy should be observed in response to fast translations on a flat surface also, provided the feet are constrained to remain in contact with the floor and the knee is constrained to remain straight. The purpose of this study was to examine the experimental evidence for hip strategy in postural responses to backward translations of a flat support surface and to determine whether analyses of joint torques would provide evidence for two separate postural strategies. Normal subjects standing on a flat support surface were translated backward with a range of velocities from fast (55 cm/s) to slow (5 cm/s). EMG activations and joint kinematics showed pattern changes consistent with previous experimental descriptions of mixed hip and ankle strategy with increasing platform velocity. Joint torque analyses revealed the addition of a hip flexor torque to the ankle plantarflexor torque during fast translations. This finding indicates the addition of hip strategy to ankle strategy to produce a continuum of postural responses. Hip torque without accompanying ankle torque (pure hip strategy) was not observed. Although postural control strategies have previously been defined by how the body moves, we conclude that joint torques, which indicate how body movements are produced, are useful in defining postural control strategies. These results also illustrate how the biomechanics of the body can transform discrete control

  4. A Hybrid Functional Electrical Stimulation for Real-Time Estimation of Joint Torque and Closed-Loop Control of Muscle Activation

    PubMed Central

    Li, Zhan; Guiraud, David; Andreu, David; Fattal, Charles; Gelis, Anthony; Hayashibe, Mitsuhiro

    2016-01-01

    As a neuroprosthetic technique, functional electrical stimulation (FES) can restore lost motor performance of impaired patients. Through delivering electrical pulses to target muscles, the joint movement can be eventually elicited. This work presents a real-time FES system which is able to deal with two neuroprosthetic missions: one is estimating FES-induced joint torque with evoked electromyograph (eEMG), and the other is artificially controlling muscle activation with such eEMG feedback. The clinical experiment results on spinal cord injured (SCI) patients and healthy subjects show promising performance of the proposed FES system. PMID:27990235

  5. Results and Analysis from Space Suit Joint Torque Testing

    NASA Technical Reports Server (NTRS)

    Matty, Jennifer E.; Aitchison, Lindsay

    2009-01-01

    A space suit s mobility is critical to an astronaut s ability to perform work efficiently. As mobility increases, the astronaut can perform tasks for longer durations with less fatigue. The term mobility, with respect to space suits, is defined in terms of two key components: joint range of motion and joint torque. Individually these measures describe the path which in which a joint travels and the force required to move it through that path. Previous space suits mobility requirements were defined as the collective result of these two measures and verified by the completion of discrete functional tasks. While a valid way to impose mobility requirements, such a method does necessitate a solid understanding of the operational scenarios in which the final suit will be performing. Because the Constellation space suit system requirements are being finalized with a relatively immature concept of operations, the Space Suit Element team elected to define mobility in terms of its constituent parts to increase the likelihood that the future pressure garment will be mobile enough to enable a broad scope of undefined exploration activities. The range of motion requirements were defined by measuring the ranges of motion test subjects achieved while performing a series of joint maximizing tasks in a variety of flight and prototype space suits. The definition of joint torque requirements has proved more elusive. NASA evaluated several different approaches to the problem before deciding to generate requirements based on unmanned joint torque evaluations of six different space suit configurations being articulated through 16 separate joint movements. This paper discusses the experiment design, data analysis and results, and the process used to determine the final values for the Constellation pressure garment joint torque requirements.

  6. Results and Analysis from Space Suit Joint Torque Testing

    NASA Technical Reports Server (NTRS)

    Matty, Jennifer

    2010-01-01

    This joint mobility KC lecture included information from two papers, "A Method for and Issues Associated with the Determination of Space Suit Joint Requirements" and "Results and Analysis from Space Suit Joint Torque Testing," as presented for the International Conference on Environmental Systems in 2009 and 2010, respectively. The first paper discusses historical joint torque testing methodologies and approaches that were tested in 2008 and 2009. The second paper discusses the testing that was completed in 2009 and 2010.

  7. Dimensionality of joint torques and muscle patterns for reaching

    PubMed Central

    Russo, Marta; D'Andola, Mattia; Portone, Alessandro; Lacquaniti, Francesco; d'Avella, Andrea

    2014-01-01

    Muscle activities underlying many motor behaviors can be generated by a small number of basic activation patterns with specific features shared across movement conditions. Such low-dimensionality suggests that the central nervous system (CNS) relies on a modular organization to simplify control. However, the relationship between the dimensionality of muscle patterns and that of joint torques is not fixed, because of redundancy and non-linearity in mapping the former into the latter, and needs to be investigated. We compared the torques acting at four arm joints during fast reaching movements in different directions in the frontal and sagittal planes and the underlying muscle patterns. The dimensionality of the non-gravitational components of torques and muscle patterns in the spatial, temporal, and spatiotemporal domains was estimated by multidimensional decomposition techniques. The spatial organization of torques was captured by two or three generators, indicating that not all the available coordination patterns are employed by the CNS. A single temporal generator with a biphasic profile was identified, generalizing previous observations on a single plane. The number of spatiotemporal generators was equal to the product of the spatial and temporal dimensionalities and their organization was essentially synchronous. Muscle pattern dimensionalities were higher than torques dimensionalities but also higher than the minimum imposed by the inherent non-negativity of muscle activations. The spatiotemporal dimensionality of the muscle patterns was lower than the product of their spatial and temporal dimensionality, indicating the existence of specific asynchronous coordination patterns. Thus, the larger dimensionalities of the muscle patterns may be required for CNS to overcome the non-linearities of the musculoskeletal system and to flexibly generate endpoint trajectories with simple kinematic features using a limited number of building blocks. PMID:24624078

  8. Measurement of Resistive Torques in Major Human Joints

    DTIC Science & Technology

    1979-04-01

    Joints Knee Joint Resistive Torques Hip Joint Resistive Moments Elbow Joint Ankle Joint 20. ABSTRACT (Continue on reverse side if necessary and...applications. The major articulating Joints which are considered are the shoulder, knee, hip, elbow and ankle. Due DD I J 1473 EDITION OF I NOV 65 IS OBSOLETE...47 Force is being applied by means of the GFA on the subject’s lower arm for the elbow joint resistive force and moment data collection

  9. Joint Torque Reduction of a Three Dimensional Redundant Planar Manipulator

    PubMed Central

    Yahya, Samer; Moghavvemi, Mahmoud; Almurib, Haider Abbas F.

    2012-01-01

    Research on joint torque reduction in robot manipulators has received considerable attention in recent years. Minimizing the computational complexity of torque optimization and the ability to calculate the magnitude of the joint torque accurately will result in a safe operation without overloading the joint actuators. This paper presents a mechanical design for a three dimensional planar redundant manipulator with the advantage of the reduction in the number of motors needed to control the joint angle, leading to a decrease in the weight of the manipulator. Many efforts have been focused on decreasing the weight of manipulators, such as using lightweight joints design or setting the actuators at the base of the manipulator and using tendons for the transmission of power to these joints. By using the design of this paper, only three motors are needed to control any n degrees of freedom in a three dimensional planar redundant manipulator instead of n motors. Therefore this design is very effective to decrease the weight of the manipulator as well as the number of motors needed to control the manipulator. In this paper, the torque of all the joints are calculated for the proposed manipulator (with three motors) and the conventional three dimensional planar manipulator (with one motor for each degree of freedom) to show the effectiveness of the proposed manipulator for decreasing the weight of the manipulator and minimizing driving joint torques. PMID:22969326

  10. Virtual Passive Controller for Robot Systems Using Joint Torque Sensors

    NASA Technical Reports Server (NTRS)

    Aldridge, Hal A.; Juang, Jer-Nan

    1997-01-01

    This paper presents a control method based on virtual passive dynamic control that will stabilize a robot manipulator using joint torque sensors and a simple joint model. The method does not require joint position or velocity feedback for stabilization. The proposed control method is stable in the sense of Lyaponov. The control method was implemented on several joints of a laboratory robot. The controller showed good stability robustness to system parameter error and to the exclusion of nonlinear dynamic effects on the joints. The controller enhanced position tracking performance and, in the absence of position control, dissipated joint energy.

  11. Results and Analysis from Space Suit Joint Torque Testing

    NASA Technical Reports Server (NTRS)

    Matty, Jennifer

    2010-01-01

    A space suit's mobility is critical to an astronaut's ability to perform work efficiently. As mobility increases, the astronaut can perform tasks for longer durations with less fatigue. Mobility can be broken down into two parts: range of motion (ROM) and torque. These two measurements describe how the suit moves and how much force it takes to move. Two methods were chosen to define mobility requirements for the Constellation Space Suit Element (CSSE). One method focuses on range of motion and the second method centers on joint torque. A joint torque test was conducted to determine a baseline for current advanced space suit joint torques. This test utilized the following space suits: Extravehicular Mobility Unit (EMU), Advanced Crew Escape Suit (ACES), I-Suit, D-Suit, Enhanced Mobility (EM)- ACES, and Mark III (MK-III). Data was collected data from 16 different joint movements of each suit. The results were then reviewed and CSSE joint torque requirement values were selected. The focus of this paper is to discuss trends observed during data analysis.

  12. The effect of movement direction on joint torque covariation.

    PubMed

    Shemmell, Jonathan; Hasan, Ziaul; Gottlieb, Gerald L; Corcos, Daniel M

    2007-01-01

    It has been proposed that unconstrained upper limb movements are coordinated via a kinetic constraint that produces dynamic muscle torques at each moving joint that are a linear function of a single torque command. This constraint has been termed linear synergy (Gottlieb et al. J Neurophysiol 75:1760-1764, 1996). The current study tested two hypotheses: (1) that the extent of covariation between dynamic muscle torques at the shoulder and elbow varied with the direction of movement and (2) that the extent to which muscle torques deviated from linear synergy would be reproduced by a simulation of pointing movements in which the path of the hand was constrained to be straight. Dynamic muscle torques were calculated from sagittal plane pointing movements performed by 12 participants to targets in eight different directions. The results of principal component analyses performed on the muscle torque data demonstrated direction-dependent variation in the extent to which dynamic muscle torques covaried at the shoulder and elbow. Linear synergy was deviated from substantially in movement directions for which the magnitude of muscle torque was low at one joint. A simulation of movements with straight hand paths was able to accurately estimate the amount of covariation between muscle torques at the two joints in many directions. These results support the idea that a kinematic constraint is imposed by the central nervous system during unconstrained pointing movements. Linear synergy may also be applied as a coordinating constraint in circumstances where its application allows the path of the moving endpoint to remain close to a straight line.

  13. Isometric and isokinetic torque curves at the knee joint.

    PubMed

    Yoon, T S; Park, D S; Kang, S W; Chun, S I; Shin, J S

    1991-03-01

    Isometric and isokinetic torques of bilateral quadriceps and hamstrings were measured with Isokinetic Rehabilitation and Testing System (Model No. Cybex 340) on 40 normal untrained subjects, 20 males and 20 females, ranging between the ages of 23 and 35 years. The mean peak isometric and isokinetic torque values of both muscle groups showed no significant differences between dominant (right) and nondominant (left) limbs in both sexes; however there were significant differences between the male and the female. As the angular velocity increased, the peak torque significantly decreased, and the point of peak torque output occurred significantly later in the range of motion for quadriceps and hamstrings (p less than 0.01). There were no significant changes in the hamstrings to quadriceps (H/Q) ratios as the angular velocity increased. However, there were significant differences of mean H/Q ratio between male and female (p less than 0.01). Height had significant positive correlation with peak isometric and isokinetic torques for both quadriceps and hamstrings (p less than 0.01). Weight was found to correlate significantly with peak isometric and isokinetic torques (p less than 0.01). The mean isometric torques were significantly higher than the mean isokinetic torques for any joint angles in both sexes (p less than .01).

  14. Muscle torque preservation and physical activity in individuals with stroke

    PubMed Central

    Eng, Janice J.; Lomaglio, Melanie J.; MacIntyre, Donna L.

    2011-01-01

    Background A greater percent loss of concentric versus eccentric muscle torque (i.e., relative eccentric muscle torque preservation) has been reported in the paretic limb of individuals with stroke and has been attributed to hypertonia and/or co-contractions. Stroke provides a unique condition for examining mechanisms underlying eccentric muscle preservation because both limbs experience similar amounts of general physical activity, but the paretic side is impaired directly by the brain lesion. Purpose The purpose of this study was to determine 1) whether eccentric preservation also exists in the nonparetic limb and 2) the relationship of eccentric or concentric torque preservation with physical activity in stroke. We hypothesized that the nonparetic muscles would demonstrate eccentric muscle preservation, which would suggest that non-neural mechanisms may also contribute to its relative preservation. Methods Eighteen stroke and 18 healthy control subjects (age and sex matched) completed a physical activity questionnaire. Maximum voluntary concentric and eccentric joint torques of the ankle, knee and hip flexors and extensors were measured using an isokinetic dynamometer at 30°/s for the paretic and nonparetic muscles. Relative concentric and eccentric peak torque preservation were expressed as a percentage of control subject torque. Results Relative eccentric torque was higher (more preserved) than relative concentric torque for paretic, as well as nonparetic muscles. Physical activity correlated with paretic (r=0.640, p=0.001) and nonparetic concentric torque preservation (r=0.508, p=0.009), but not with eccentric torque preservation for either leg. Conclusions The relative preservation of eccentric torque in the nonparetic muscles suggest a role of non-neural mechanisms and could also explain the preservation observed in other chronic health conditions. Loss of concentric, but not eccentric muscle torque was related to physical inactivity in stroke. PMID

  15. Active Vibration Control of a Large Flexible Manipulator by Inertial Force and Joint Torque. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Lee, Soo Han

    1988-01-01

    The efficiency and positional accuracy of a lightweight flexible manipulator are limited by its flexural vibrations, which last after a gross motion is completed. The vibration delays subsequent operations. In the proposed work, the vibration is suppressed by inertial force of a small arm in addition to the joint actuators and passive damping treatment. The proposed approach is: (1) Dynamic modeling of a combined system, a large flexible manipulator and a small arm, (2) Determination of optimal sensor location and controller algorithm, and (3) Verification of the fitness of model and the performance of controller.

  16. Modelling the maximum voluntary joint torque/angular velocity relationship in human movement.

    PubMed

    Yeadon, Maurice R; King, Mark A; Wilson, Cassie

    2006-01-01

    The force exerted by a muscle is a function of the activation level and the maximum (tetanic) muscle force. In "maximum" voluntary knee extensions muscle activation is lower for eccentric muscle velocities than for concentric velocities. The aim of this study was to model this "differential activation" in order to calculate the maximum voluntary knee extensor torque as a function of knee angular velocity. Torque data were collected on two subjects during maximal eccentric-concentric knee extensions using an isovelocity dynamometer with crank angular velocities ranging from 50 to 450 degrees s(-1). The theoretical tetanic torque/angular velocity relationship was modelled using a four parameter function comprising two rectangular hyperbolas while the activation/angular velocity relationship was modelled using a three parameter function that rose from submaximal activation for eccentric velocities to full activation for high concentric velocities. The product of these two functions gave a seven parameter function which was fitted to the joint torque/angular velocity data, giving unbiased root mean square differences of 1.9% and 3.3% of the maximum torques achieved. Differential activation accounts for the non-hyperbolic behaviour of the torque/angular velocity data for low concentric velocities. The maximum voluntary knee extensor torque that can be exerted may be modelled accurately as the product of functions defining the maximum torque and the maximum voluntary activation level. Failure to include differential activation considerations when modelling maximal movements will lead to errors in the estimation of joint torque in the eccentric phase and low velocity concentric phase.

  17. Absolute reliability of hamstring to quadriceps strength imbalance ratios calculated using peak torque, joint angle-specific torque and joint ROM-specific torque values.

    PubMed

    Ayala, F; De Ste Croix, M; Sainz de Baranda, P; Santonja, F

    2012-11-01

    The main purpose of this study was to determine the absolute reliability of conventional (H/Q(CONV)) and functional (H/Q(FUNC)) hamstring to quadriceps strength imbalance ratios calculated using peak torque values, 3 different joint angle-specific torque values (10°, 20° and 30° of knee flexion) and 4 different joint ROM-specific average torque values (0-10°, 11-20°, 21-30° and 0-30° of knee flexion) adopting a prone position in recreational athletes. A total of 50 recreational athletes completed the study. H/Q(CONV) and H/Q(FUNC) ratios were recorded at 3 different angular velocities (60, 180 and 240°/s) on 3 different occasions with a 72-96 h rest interval between consecutive testing sessions. Absolute reliability was examined through typical percentage error (CVTE), percentage change in the mean (CM) and intraclass correlations (ICC) as well as their respective confidence limits. H/Q(CONV) and H/Q(FUNC) ratios calculated using peak torque values showed moderate reliability values, with CM scores lower than 2.5%, CV(TE) values ranging from 16 to 20% and ICC values ranging from 0.3 to 0.7. However, poor absolute reliability scores were shown for H/Q(CONV) and H/Q(FUNC) ratios calculated using joint angle-specific torque values and joint ROM-specific average torque values, especially for H/Q(FUNC) ratios (CM: 1-23%; CV(TE): 22-94%; ICC: 0.1-0.7). Therefore, the present study suggests that the CV(TE) values reported for H/Q(CONV) and H/Q(FUNC) (≈18%) calculated using peak torque values may be sensitive enough to detect large changes usually observed after rehabilitation programmes but not acceptable to examine the effect of preventitive training programmes in healthy individuals. The clinical reliability of hamstring to quadriceps strength ratios calculated using joint angle-specific torque values and joint ROM-specific average torque values are questioned and should be re-evaluated in future research studies.

  18. A robotic apparatus that dictates torque fields around joints without affecting inherent joint dynamics.

    PubMed

    Oytam, Yalchin; Lloyd, David; Reid, Campbell S; de Rugy, Aymar; Carson, Richard G

    2010-10-01

    This manuscript describes how motor behaviour researchers who are not at the same time expert roboticists may implement an experimental apparatus, which has the ability to dictate torque fields around a single joint on one limb or single joints on multiple limbs without otherwise interfering with the inherent dynamics of those joints. Such an apparatus expands the exploratory potential of the researcher wherever experimental distinction of factors may necessitate independent control of torque fields around multiple limbs, or the shaping of torque fields of a given joint independently of its plane of motion, or its directional phase within that plane. The apparatus utilizes torque motors. The challenge with torque motors is that they impose added inertia on limbs and thus attenuate joint dynamics. We eliminated this attenuation by establishing an accurate mathematical model of the robotic device using the Box-Jenkins method, and cancelling out its dynamics by employing the inverse of the model as a compensating controller. A direct measure of the remnant inertial torque as experienced by the hand during a 50 s period of wrist oscillations that increased gradually in frequency from 1.0 to 3.8 Hz confirmed that the removal of the inertial effect of the motor was effectively complete.

  19. Influence of joint angle on EMG-torque model during constant-posture, quasi-constant-torque contractions.

    PubMed

    Liu, Pu; Liu, Lukai; Martel, Francois; Rancourt, Denis; Clancy, Edward A

    2013-10-01

    Electromyogram (EMG)-torque modeling is of value to many different application areas, including ergonomics, clinical biomechanics and prosthesis control. One important aspect of EMG-torque modeling is the ability to account for the joint angle influence. This manuscript describes an experimental study which relates the biceps/triceps surface EMG of 12 subjects to elbow torque at seven joint angles (spanning 45-135°) during constant-posture, quasi-constant-torque contractions. Advanced EMG amplitude (EMGσ) estimation processors (i.e., whitened, multiple-channel) were investigated and three non-linear EMGσ-torque models were evaluated. When EMG-torque models were formed separately for each of the seven distinct joint angles, a minimum "gold standard" error of 4.23±2.2% MVCF90 resulted (i.e., error relative to maximum voluntary contraction at 90° flexion). This model structure, however, did not directly facilitate interpolation across angles. The best model which did so (i.e., parameterized the angle dependence), achieved an error of 4.17±1.7% MVCF90. Results demonstrated that advanced EMGσ processors lead to improved joint torque estimation. We also contrasted models that did vs. did not account for antagonist muscle co-contraction. Models that accounted for co-contraction estimated individual flexion muscle torques that were ∼29% higher and individual extension muscle torques that were ∼68% higher.

  20. Effect of BMI on knee joint torques in ergometer rowing.

    PubMed

    Roemer, Karen; Hortobagyi, Tibor; Richter, Chris; Munoz-Maldonado, Yolanda; Hamilton, Stephanie

    2013-12-01

    Although an authoritative panel recommended the use of ergometer rowing as a non-weight-bearing form of exercise for obese adults, the biomechanical characterization of ergometer rowing is strikingly absent. We examined the interaction between body mass index (BMI) relative to the lower extremity biomechanics during rowing in 10 normal weight (BMI 18-25), 10 overweight (BMI 25-30 kg·m⁻²), and 10 obese (BMI > 30 kg·m⁻²) participants. The results showed that BMI affects joint kinematics and primarily knee joint kinetics. The data revealed that high BMI leads to unfavorable knee joint torques, implying increased loads of the medial compartment in the knee joint that could be avoided by allowing more variable foot positioning on future designs of rowing ergometers.

  1. Influence of Joint Angle on EMG-Torque Model During Constant-Posture, Torque-Varying Contractions.

    PubMed

    Liu, Pu; Liu, Lukai; Clancy, Edward A

    2015-11-01

    Relating the electromyogram (EMG) to joint torque is useful in various application areas, including prosthesis control, ergonomics and clinical biomechanics. Limited study has related EMG to torque across varied joint angles, particularly when subjects performed force-varying contractions or when optimized modeling methods were utilized. We related the biceps-triceps surface EMG of 22 subjects to elbow torque at six joint angles (spanning 60° to 135°) during constant-posture, torque-varying contractions. Three nonlinear EMG σ -torque models, advanced EMG amplitude (EMG σ ) estimation processors (i.e., whitened, multiple-channel) and the duration of data used to train models were investigated. When EMG-torque models were formed separately for each of the six distinct joint angles, a minimum "gold standard" error of 4.01±1.2% MVC(F90) resulted (i.e., error relative to maximum voluntary contraction at 90° flexion). This model structure, however, did not directly facilitate interpolation across angles. The best model which did so achieved a statistically equivalent error of 4.06±1.2% MVC(F90). Results demonstrated that advanced EMG σ processors lead to improved joint torque estimation as do longer model training durations.

  2. Maximum voluntary joint torque as a function of joint angle and angular velocity: model development and application to the lower limb.

    PubMed

    Anderson, Dennis E; Madigan, Michael L; Nussbaum, Maury A

    2007-01-01

    Measurements of human strength can be important during analyses of physical activities. Such measurements have often taken the form of the maximum voluntary torque at a single joint angle and angular velocity. However, the available strength varies substantially with joint position and velocity. When examining dynamic activities, strength measurements should account for these variations. A model is presented of maximum voluntary joint torque as a function of joint angle and angular velocity. The model is based on well-known physiological relationships between muscle force and length and between muscle force and velocity and was tested by fitting it to maximum voluntary joint torque data from six different exertions in the lower limb. Isometric, concentric and eccentric maximum voluntary contractions were collected during hip extension, hip flexion, knee extension, knee flexion, ankle plantar flexion and dorsiflexion. Model parameters are reported for each of these exertion directions by gender and age group. This model provides an efficient method by which strength variations with joint angle and angular velocity may be incorporated into comparisons between joint torques calculated by inverse dynamics and the maximum available joint torques.

  3. Control of torque direction by spinal pathways at the cat ankle joint.

    PubMed

    Nichols, T R; Lawrence, J H; Bonasera, S J

    1993-01-01

    To study the biomechanics of the calcaneal tendon's complex insertion onto the calcaneus, we measured torque-time trajectories exerted by the triceps surae and tibialis anterior muscles in eight unanesthetized decerebrate cats using a multi-axis force-moment sensor placed at the ankle joint. The ankle was constrained to an angle of 110 degrees plantarflexion. Muscles were activated using crossed-extension (XER), flexion (FWR), and caudal cutaneous sural nerve (SNR) reflexes. Torque contributions of other muscles activated by these reflexes were eliminated by denervation or tenotomy. In two animals, miniature pressure transducers were implanted among tendon fibers from the lateral gastrocnemius (LG) muscle that insert straight into the calcaneus or among tendon fibers from the medial gastrocnemius (MG) that cross over and insert on the lateral aspect of calcaneus. Reflexively evoked torques had the following directions: FWR, dorsiflexion and adduction; SNR, plantarflexion and abduction; and XER, plantarflexion and modest abduction or adduction. The proportion of abduction torque to plantarflexion torque was always greater for SNR than XER; this difference was about 50% of the magnitude of abduction torque generated by tetanic stimulation of the peronei. During SNR, pressures were higher in regions of the calcaneal tendon originating from MG than regions originating from LG. Similarly, pressures within the MG portion of the calcaneal tendon were higher during SNR than during XER, although these two reflexes produced matched ankle plantarflexion forces. Selective tenotomies and electromyographic recordings further demonstrated that MG generated most of the torque in response to SNR, while soleus, LG, and MG all generated torques in response to XER.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Torque linearizing hardware for the electric joint motors of a direct-drive robot

    SciTech Connect

    Muir, P.F.; Bryan, J.R.

    1991-12-31

    Many emerging high-performance robot control algorithms require the command of the joint torques; yet no known commercial robots provide such a capability. In this paper, we describe the design, development, testing and application of a VMEbus-based torque linearizing joint interface board (JIB). One JIB resides between the robot control processor and each joint motor amplifier. The JIB provides the control processor with the capability to read the motor position and apply accurate motor torques. The torque command capability derives from the application of a 128k {times} 8 EPROM lookup table for each motor phase. Because joint motor torque is dependent upon the torque command and the motor position, the hardware is designed to utilize the torque command and the current motor position as the address to retrieve the proper pulse-width for the PWM motor amplifier. The table look-up cycle operates independently of the robot controller at a 40KHz rate to provide constant joint torque as the motor rotates. We identify the proper table entries by an automated in situ data collection procedure. Static torque generation results show that the torque deviations are reduced from as much as 76% to below 5% for each of the three direct-drive motors (two are variable reluctance motors and one is brushless DC) on an AdeptTwo robot. These torque deviations are reduced below 2.5% if only the upper 90% of the torque range is considered. The torque deviations of the non-direct-drive joint are reduced by 50%. Dynamic robot edge following experiments show that the robot speed of operation can be more than doubled for a given applied force accuracy by utilizing the joint torque linearizing boards. 8 refs.

  5. Torque linearizing hardware for the electric joint motors of a direct-drive robot

    SciTech Connect

    Muir, P.F.; Bryan, J.R.

    1991-01-01

    Many emerging high-performance robot control algorithms require the command of the joint torques; yet no known commercial robots provide such a capability. In this paper, we describe the design, development, testing and application of a VMEbus-based torque linearizing joint interface board (JIB). One JIB resides between the robot control processor and each joint motor amplifier. The JIB provides the control processor with the capability to read the motor position and apply accurate motor torques. The torque command capability derives from the application of a 128k {times} 8 EPROM lookup table for each motor phase. Because joint motor torque is dependent upon the torque command and the motor position, the hardware is designed to utilize the torque command and the current motor position as the address to retrieve the proper pulse-width for the PWM motor amplifier. The table look-up cycle operates independently of the robot controller at a 40KHz rate to provide constant joint torque as the motor rotates. We identify the proper table entries by an automated in situ data collection procedure. Static torque generation results show that the torque deviations are reduced from as much as 76% to below 5% for each of the three direct-drive motors (two are variable reluctance motors and one is brushless DC) on an AdeptTwo robot. These torque deviations are reduced below 2.5% if only the upper 90% of the torque range is considered. The torque deviations of the non-direct-drive joint are reduced by 50%. Dynamic robot edge following experiments show that the robot speed of operation can be more than doubled for a given applied force accuracy by utilizing the joint torque linearizing boards. 8 refs.

  6. Torque linearizing hardware for the electric joint motors of a direct-drive robot

    NASA Astrophysics Data System (ADS)

    Muir, P. F.; Bryan, J. R.

    Many emerging high-performance robot control algorithms require the command of the joint torques, yet no known commercial robots provide such a capability. We describe the design, development, testing, and application of a VMEbus-based torque linearizing joint interface board (JIB). One JIB resides between the robot control processor and each joint motor amplifier. The JIB provides the control processor with the capability to read the motor position and apply accurate motor torques. The torque command capability derives from the application of a 128k x 8 EPROM lookup table for each motor phase. Because joint motor torque is dependent upon the torque command and the motor position, the hardware is designed to utilize the torque command and the current motor position as the address to retrieve the proper pulse-width for the PWM motor amplifier. The table look-up cycle operates independently of the robot controller at a 40KHz rate to provide constant joint torque as the motor rotates. We identify the proper table entries by an automated in situ data collection procedure. Static torque generation results show that the torque deviations are reduced from as much as 76 percent to below 5 percent for each of the three direct-drive motors (two are variable reluctance motors and one is brushless DC) on an AdeptTwo robot. These torque deviations are reduced below 2.5 percent if only the upper 90 percent of the torque range is considered. The torque deviations of the non-direct-drive joint are reduced by 50 percent. Dynamic robot edge following experiments show that the robot speed of operation can be more than doubled for a given applied force accuracy by utilizing the joint torque linearizing boards.

  7. Isokinetic Identification of Knee Joint Torques before and after Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Czaplicki, Adam; Jarocka, Marta; Walawski, Jacek

    2015-01-01

    The aim of this study was to evaluate the serial change of isokinetic muscle strength of the knees before and after anterior cruciate ligament reconstruction (ACLR) in physically active males and to estimate the time of return to full physical fitness. Extension and flexion torques were measured for the injured and healthy limbs at two angular velocities approximately 1.5 months before the surgery and 3, 6, and 12 months after ACLR. Significant differences (p ≤ 0.05) in peak knee extension and flexion torques, hamstring/quadriceps (H/Q) strength ratios, uninvolved/involved limb peak torque ratios, and the normalized work of these muscles between the four stages of rehabilitation were identified. Significant differences between extension peak torques for the injured and healthy limbs were also detected at all stages. The obtained results showed that 12 months of rehabilitation were insufficient for the involved knee joint to recover its strength to the level of strength of the uninvolved knee joint. The results helped to evaluate the progress of the rehabilitation and to implement necessary modifications optimizing the rehabilitation training program. The results of the study may also be used as referential data for physically active males of similar age. PMID:26646385

  8. Joint torques in a freely walking insect reveal distinct functions of leg joints in propulsion and posture control.

    PubMed

    Dallmann, Chris J; Dürr, Volker; Schmitz, Josef

    2016-01-27

    Determining the mechanical output of limb joints is critical for understanding the control of complex motor behaviours such as walking. In the case of insect walking, the neural infrastructure for single-joint control is well described. However, a detailed description of the motor output in form of time-varying joint torques is lacking. Here, we determine joint torques in the stick insect to identify leg joint function in the control of body height and propulsion. Torques were determined by measuring whole-body kinematics and ground reaction forces in freely walking animals. We demonstrate that despite strong differences in morphology and posture, stick insects show a functional division of joints similar to other insect model systems. Propulsion was generated by strong depression torques about the coxa-trochanter joint, not by retraction or flexion/extension torques. Torques about the respective thorax-coxa and femur-tibia joints were often directed opposite to fore-aft forces and joint movements. This suggests a posture-dependent mechanism that counteracts collapse of the leg under body load and directs the resultant force vector such that strong depression torques can control both body height and propulsion. Our findings parallel propulsive mechanisms described in other walking, jumping and flying insects, and challenge current control models of insect walking.

  9. Joint torques in a freely walking insect reveal distinct functions of leg joints in propulsion and posture control

    PubMed Central

    2016-01-01

    Determining the mechanical output of limb joints is critical for understanding the control of complex motor behaviours such as walking. In the case of insect walking, the neural infrastructure for single-joint control is well described. However, a detailed description of the motor output in form of time-varying joint torques is lacking. Here, we determine joint torques in the stick insect to identify leg joint function in the control of body height and propulsion. Torques were determined by measuring whole-body kinematics and ground reaction forces in freely walking animals. We demonstrate that despite strong differences in morphology and posture, stick insects show a functional division of joints similar to other insect model systems. Propulsion was generated by strong depression torques about the coxa–trochanter joint, not by retraction or flexion/extension torques. Torques about the respective thorax–coxa and femur–tibia joints were often directed opposite to fore–aft forces and joint movements. This suggests a posture-dependent mechanism that counteracts collapse of the leg under body load and directs the resultant force vector such that strong depression torques can control both body height and propulsion. Our findings parallel propulsive mechanisms described in other walking, jumping and flying insects, and challenge current control models of insect walking. PMID:26791608

  10. Improving anterior deltoid activity in a musculoskeletal shoulder model - an analysis of the torque-feasible space at the sternoclavicular joint.

    PubMed

    Ingram, David; Engelhardt, Christoph; Farron, Alain; Terrier, Alexandre; Müllhaupt, Philippe

    2016-01-01

    Modelling the shoulder's musculature is challenging given its mechanical and geometric complexity. The use of the ideal fibre model to represent a muscle's line of action cannot always faithfully represent the mechanical effect of each muscle, leading to considerable differences between model-estimated and in vivo measured muscle activity. While the musculo-tendon force coordination problem has been extensively analysed in terms of the cost function, only few works have investigated the existence and sensitivity of solutions to fibre topology. The goal of this paper is to present an analysis of the solution set using the concepts of torque-feasible space (TFS) and wrench-feasible space (WFS) from cable-driven robotics. A shoulder model is presented and a simple musculo-tendon force coordination problem is defined. The ideal fibre model for representing muscles is reviewed and the TFS and WFS are defined, leading to the necessary and sufficient conditions for the existence of a solution. The shoulder model's TFS is analysed to explain the lack of anterior deltoid (DLTa) activity. Based on the analysis, a modification of the model's muscle fibre geometry is proposed. The performance with and without the modification is assessed by solving the musculo-tendon force coordination problem for quasi-static abduction in the scapular plane. After the proposed modification, the DLTa reaches 20% of activation.

  11. Comparing different approaches for determining joint torque parameters from isovelocity dynamometer measurements.

    PubMed

    Forrester, S E; Yeadon, M R; King, M A; Pain, M T G

    2011-03-15

    Strength, or maximum joint torque, is a fundamental factor governing human movement, and is regularly assessed for clinical and rehabilitative purposes as well as for research into human performance. This study aimed to identify the most appropriate protocol for fitting a maximum voluntary torque function to experimental joint torque data. Three participants performed maximum isometric and concentric-eccentric knee extension trials on an isovelocity dynamometer and a separate experimental protocol was used to estimate maximum knee extension angular velocity. A nine parameter maximum voluntary torque function, which included angle, angular velocity and neural inhibition effects, was fitted to the experimental torque data and three aspects of this fitting protocol were investigated. Using an independent experimental estimate of maximum knee extension angular velocity gave lower variability in the high concentric velocity region of the maximum torque function compared to using dynamometer measurements alone. A weighted root mean square difference (RMSD) score function, that forced the majority (73-92%) of experimental data beneath the maximum torque function, was found to best account for the one-sided noise in experimental torques resulting from sub-maximal effort by the participants. The suggested protocol (an appropriately weighted RMSD score function and an independent estimate of maximum knee extension angular velocity) gave a weighted RMSD of between 11 and 13 Nm (4-5% of maximum isometric torque). It is recommended that this protocol be used in generating maximum voluntary joint torque functions in all torque-based modelling of dynamic human movement.

  12. Integrated High-Speed Torque Control System for a Robotic Joint

    NASA Technical Reports Server (NTRS)

    Davis, Donald R. (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Valvo, Michael C. (Inventor); Askew, R. Scott (Inventor)

    2013-01-01

    A control system for achieving high-speed torque for a joint of a robot includes a printed circuit board assembly (PCBA) having a collocated joint processor and high-speed communication bus. The PCBA may also include a power inverter module (PIM) and local sensor conditioning electronics (SCE) for processing sensor data from one or more motor position sensors. Torque control of a motor of the joint is provided via the PCBA as a high-speed torque loop. Each joint processor may be embedded within or collocated with the robotic joint being controlled. Collocation of the joint processor, PIM, and high-speed bus may increase noise immunity of the control system, and the localized processing of sensor data from the joint motor at the joint level may minimize bus cabling to and from each control node. The joint processor may include a field programmable gate array (FPGA).

  13. Lumbar joint torque estimation based on simplified motion measurement using multiple inertial sensors.

    PubMed

    Miyajima, Saori; Tanaka, Takayuki; Imamura, Yumeko; Kusaka, Takashi

    2015-01-01

    We estimate lumbar torque based on motion measurement using only three inertial sensors. First, human motion is measured by a 6-axis motion tracking device that combines a 3-axis accelerometer and a 3-axis gyroscope placed on the shank, thigh, and back. Next, the lumbar joint torque during the motion is estimated by kinematic musculoskeletal simulation. The conventional method for estimating joint torque uses full body motion data measured by an optical motion capture system. However, in this research, joint torque is estimated by using only three link angles of the body, thigh, and shank. The utility of our method was verified by experiments. We measured motion of bendung knee and waist simultaneously. As the result, we were able to estimate the lumbar joint torque from measured motion.

  14. Converting a commercial electric direct-drive robot to operate from joint torque commands

    SciTech Connect

    Muir, P.F.

    1991-07-01

    Many robot control algorithms for high performance in-contact operations including hybrid force/position, stiffness control and impedance control approaches require the command the joint torques. However, most commercially available robots do not provide joint torque command capabilities. The joint command at the user level is typically position or velocity and at the control developer level is voltage, current, or pulse-width, and the torque generated is a nonlinear function of the command and joint position. To enable the application of high performance in-contact control algorithms to commercially available robots, and thereby facilitate technology transfer from the robot control research community to commercial applications, an methodology has been developed to linearize the torque characteristics of electric motor-amplifier combinations. A four degree of freedom Adept 2 robot, having pulse-width modulation amplifiers and both variable reluctance and brushless DC motors, is converted to operate from joint torque commands to demonstrate the methodology. The commercial robot controller is replaced by a VME-based system incorporating special purpose hardware and firmware programmed from experimental data. The performance improvement is experimentally measured and graphically displayed using three-dimensional plots of torque vs command vs position. The average percentage torque deviation over the command and position ranges is reduced from as much as 76% to below 5% for the direct-drive joints 1, 2 and 4 and is cut by one half in the remaining ball-screw driven joint 3. Further, the torque deviation of the direct-drive joints drops below 2.5% if only the upper 90% of the torque range is considered. 23 refs., 20 figs., 2 tabs.

  15. Antagonist mechanical contribution to resultant maximal torque at the ankle joint in young and older men.

    PubMed

    Simoneau, Emilie M; Billot, Maxime; Martin, Alain; Van Hoecke, Jacques

    2009-04-01

    A recorded muscular torque at one joint is a resultant torque corresponding to the participation of both agonist and antagonist muscles. This study aimed to examine the effect of aging on the mechanical contributions of both plantar- and dorsi-flexors to the resultant maximal voluntary contraction (MVC) torques exerted at the ankle joint, in dorsi-flexion (DF) and plantar-flexion (PF). The estimation of isometric agonist and antagonist torques by means of an EMG biofeedback technique was made with nine young (mean age 24 years) and nine older (mean age 80 years) men. While there was a non-significant age-related decline in the measured resultant DF MVC torque (-15%; p=0.06), there was a clear decrease in the estimated agonist MVC torque exerted by the dorsi-flexors (-39%; p=0.001). The DF-to-PF resultant MVC torque ratio was significantly lower in young than in older men (0.25 vs. 0.31; p=0.006), whereas the DF-to-PF agonist MVC torque ratio was no longer different between the two populations (0.38 vs. 0.35; p>0.05). Thus, agonist MVC torques in PF and DF would be similarly affected by aging, which could not be deduced when only resultant torques were examined.

  16. Influence of predominant patterns of coordination on the exploitation of interaction torques in a two-joint rhythmic arm movement.

    PubMed

    de Rugy, Aymar; Riek, Stephan; Carson, Richard G

    2006-11-01

    In this study we investigate the coordination between rhythmic flexion-extension (FE) and supination-pronation (SP) movements at the elbow joint-complex, while manipulating the intersegmental dynamics by means of a 2-degrees of freedom (df) robot arm. We hypothesized that constraints imposed by the structure of the neuromuscular-skeletal system would (1) result in predominant pattern(s) of coordination in the absence of interaction torques and (2) influence the capabilities of participants to exploit artificially induced interaction torques. Two experiments were conducted in which different conditions of interaction torques were applied on the SP-axis as a function of FE movements. These conditions promoted different patterns of coordination between the 2-df. Control trials conducted in the absence of interaction torques revealed that both the in-phase (supination synchronized with flexion) and the anti-phase (pronation synchronized with flexion) patterns were spontaneously established by participants. The predominance of these patterns of coordination is explained in terms of the mechanical action of bi-articular muscles acting at the elbow joint-complex, and in terms of the reflexes that link the activity of the muscles involved. Results obtained in the different conditions of interaction torques revealed that those neuromuscular-skeletal constraints either impede or favor the exploitation of intersegmental dynamics depending on the context. Interaction torques were indeed found to be exploited to a greater extent in conditions in which the profiles of interaction torques favored one of the two predominant patterns of coordination (i.e., in-phase or anti-phase) as opposed to other patterns of coordination (e.g., 90 degrees or 270 degrees). Those results are discussed in relation to recent studies reporting exploitation of interaction torques in the context of rhythmic movements.

  17. Fatigue affects peak joint torque angle in hamstrings but not in quadriceps.

    PubMed

    Coratella, Giuseppe; Bellin, Giuseppe; Beato, Marco; Schena, Federico

    2015-01-01

    Primary aim of this study was to investigate peak joint torque angle (i.e. the angle of peak torque) changes recorded during an isokinetic test before and after a fatiguing soccer match simulation. Secondarily we want to investigate functional Hecc:Qconc and conventional Hconc:Qconc ratio changes due to fatigue. Before and after a standardised soccer match simulation, twenty-two healthy male amateur soccer players performed maximal isokinetic strength tests both for hamstrings and for quadriceps muscles at 1.05 rad · s(‒1), 3.14 rad · s(‒1) and 5.24 rad · s(‒1). Peak joint torque angle, peak torque and both functional Hecc:Qconc and conventional Hconc:Qconc ratios were examined. Both dominant and non-dominant limbs were tested. Peak joint torque angle significantly increased only in knee flexors. Both eccentric and concentric contractions resulted in such increment, which occurred in both limbs. No changes were found in quadriceps peak joint torque angle. Participants experienced a significant decrease in torque both in hamstrings and in quadriceps. Functional Hecc:Qconc ratio was lower only in dominant limb at higher velocities, while Hconc:Qconc did not change. This study showed after specific fatiguing task changes in hamstrings only torque/angle relationship. Hamstrings injury risk could depend on altered torque when knee is close to extension, coupled with a greater peak torque decrement compared to quadriceps. These results suggest the use eccentric based training to prevent hamstrings shift towards shorter length.

  18. Experimental Robot Position Sensor Fault Tolerance Using Accelerometers and Joint Torque Sensors

    NASA Technical Reports Server (NTRS)

    Aldridge, Hal A.; Juang, Jer-Nan

    1997-01-01

    Robot systems in critical applications, such as those in space and nuclear environments, must be able to operate during component failure to complete important tasks. One failure mode that has received little attention is the failure of joint position sensors. Current fault tolerant designs require the addition of directly redundant position sensors which can affect joint design. The proposed method uses joint torque sensors found in most existing advanced robot designs along with easily locatable, lightweight accelerometers to provide a joint position sensor fault recovery mode. This mode uses the torque sensors along with a virtual passive control law for stability and accelerometers for joint position information. Two methods for conversion from Cartesian acceleration to joint position based on robot kinematics, not integration, are presented. The fault tolerant control method was tested on several joints of a laboratory robot. The controllers performed well with noisy, biased data and a model with uncertain parameters.

  19. Comparative analysis of methods for estimating arm segment parameters and joint torques from inverse dynamics.

    PubMed

    Piovesan, Davide; Pierobon, Alberto; Dizio, Paul; Lackner, James R

    2011-03-01

    A common problem in the analyses of upper limb unfettered reaching movements is the estimation of joint torques using inverse dynamics. The inaccuracy in the estimation of joint torques can be caused by the inaccuracy in the acquisition of kinematic variables, body segment parameters (BSPs), and approximation in the biomechanical models. The effect of uncertainty in the estimation of body segment parameters can be especially important in the analysis of movements with high acceleration. A sensitivity analysis was performed to assess the relevance of different sources of inaccuracy in inverse dynamics analysis of a planar arm movement. Eight regression models and one water immersion method for the estimation of BSPs were used to quantify the influence of inertial models on the calculation of joint torques during numerical analysis of unfettered forward arm reaching movements. Thirteen subjects performed 72 forward planar reaches between two targets located on the horizontal plane and aligned with the median plane. Using a planar, double link model for the arm with a floating shoulder, we calculated the normalized joint torque peak and a normalized root mean square (rms) of torque at the shoulder and elbow joints. Statistical analyses quantified the influence of different BSP models on the kinetic variable variance for given uncertainty on the estimation of joint kinematics and biomechanical modeling errors. Our analysis revealed that the choice of BSP estimation method had a particular influence on the normalized rms of joint torques. Moreover, the normalization of kinetic variables to BSPs for a comparison among subjects showed that the interaction between the BSP estimation method and the subject specific somatotype and movement kinematics was a significant source of variance in the kinetic variables. The normalized joint torque peak and the normalized root mean square of joint torque represented valuable parameters to compare the effect of BSP estimation methods

  20. Provocative mechanical tests of the peripheral nervous system affect the joint torque-angle during passive knee motion.

    PubMed

    Andrade, R J; Freitas, S R; Vaz, J R; Bruno, P M; Pezarat-Correia, P

    2015-06-01

    This study aimed to determine the influence of the head, upper trunk, and foot position on the passive knee extension (PKE) torque-angle response. PKE tests were performed in 10 healthy subjects using an isokinetic dynamometer at 2°/s. Subjects lay in the supine position with their hips flexed to 90°. The knee angle, passive torque, surface electromyography (EMG) of the semitendinosus and quadriceps vastus medialis, and stretch discomfort were recorded in six body positions during PKE. The different maximal active positions of the cervical spine (neutral; flexion; extension), thoracic spine (neutral; flexion), and ankle (neutral; dorsiflexion) were passively combined for the tests. Visual analog scale scores and EMG were unaffected by body segment positioning. An effect of the ankle joint was verified on the peak torque and knee maximum angle when the ankle was in the dorsiflexion position (P < 0.05). Upper trunk positioning had an effect on the knee submaximal torque (P < 0.05), observed as an increase in the knee passive submaximal torque when the cervical and thoracic spines were flexed (P < 0.05). In conclusion, other apparently mechanical unrelated body segments influence torque-angle response since different positions of head, upper trunk, and foot induce dissimilar knee mechanical responses during passive extension.

  1. Driving torque reduction in linkage mechanisms using joint compliance for robot head

    NASA Astrophysics Data System (ADS)

    Zhong, Chunhao; Yang, Xiaojun

    2015-09-01

    The conventional linkage mechanisms with compliant joint have been widely studied and implemented for increasing the adaptability of the mechanism to external contacts. However, the analysis of how compliant joints in linkage mechanism can reduce the energy consumption isn't still studied deeply. In a mobile service robot head, the actions of blinking the eyes and moving the eyeballs are realized by the planar linkage mechanism respectively. Therefore, minimizing the driving torques through motion trajectories for the linkage mechanism, which will be beneficial to extend the working time for mobile service robots. The dynamic modeling of the linkage mechanism with springs-loaded compliant joint is established. An optimization procedure for obtaining the optimal parameters of springs is proposed for minimizing the max value of driving torques within a range of desired operating conditions. The Simulations prove that the linkage mechanism with compliant joints can effectively reduce the driving torques, and reduce the energy consumption consequently. The framework can also be applied in other similar applications to reduce the driving torque and save energy. Compared with previous efforts, this is the first attempt that the linkage mechanism with complaint joint is applied in the robot head for reducing the driving torque.

  2. Immediate Effect of Grade IV Inferior Hip Joint Mobilization on Hip Abductor Torque: A Pilot Study

    PubMed Central

    Makofsky, Howard; Panicker, Siji; Abbruzzese, Jeanine; Aridas, Cynthia; Camp, Michael; Drakes, Jonelle; Franco, Caroline; Sileo, Ray

    2007-01-01

    Joint mobilization and manipulation stimulate mechanoreceptors, which may influence the joint and surrounding muscles. The purpose of this pilot study was to determine the effect of grade IV inferior hip joint mobilization on hip abductor torque. Thirty healthy subjects were randomly assigned to a control group (grade I inferior hip joint mobilization) or an experimental group (grade IV inferior hip joint mobilization). Subjects performed a pre- and post-intervention test of five isometric repetitions on the Cybex Normö dynamometer; the average torque was determined for both pre- and post-intervention measurements. These data were analyzed using the independent samples t-test with the significance level set at P<0.05. The results showed a statistically significant difference between the two groups for an increase in hip abductor torque in the experimental group (P=0.03). The experimental group demonstrated a 17.35% increase in average torque whereas the control group demonstrated a 3.68% decrease in average torque. These findings are consistent with other studies demonstrating that the use of grade IV non-thrust mobilization improves strength immediately post-intervention in healthy individuals. The results of this pilot study provide physical therapists with further support for the utilization of manual therapy in conjunction with therapeutic exercise to enhance muscle strength. PMID:19066650

  3. Reliability of metatarsophalangeal and ankle joint torque measurements by an innovative device.

    PubMed

    Man, Hok-Sum; Leung, Aaron Kam-Lun; Cheung, Jason Tak-Man; Sterzing, Thorsten

    2016-07-01

    The toe flexor muscles maintain body balance during standing and provide push-off force during walking, running, and jumping. Additionally, they are important contributing structures to maintain normal foot function. Thus, weakness of these muscles may cause poor balance, inefficient locomotion and foot deformities. The quantification of metatarsophalangeal joint (MPJ) stiffness is valuable as it is considered as a confounding factor in toe flexor muscles function. MPJ and ankle joint stiffness measurement is still largely depended on manual skills as current devices do not have good control on alignment, angular joint speed and displacement during measurement. Therefore, this study introduces an innovative dynamometer and protocol procedures for MPJ and ankle Joint torque measurement with precise and reliable foot alignment, angular joint speed and displacement control. Within-day and between-day test-retest experiments on MPJ and ankle joint torque measurement were conducted on ten and nine healthy male subjects respectively. The mean peak torques of MPJ and ankle joint of between-day and within-day measurement were 1.50±0.38Nm/deg and 1.19±0.34Nm/deg. The corresponding torques of the ankle joint were 8.24±2.20Nm/deg and 7.90±3.18Nm/deg respectively. Intraclass-correlation coefficients (ICC) of averaged peak torque of both joints of between-day and within-day test-retest experiments were ranging from 0.91 to 0.96, indicating the innovative device is systematic and reliable for the measurements and can be used for multiple scientific and clinical purposes.

  4. Torque Limit for Bolted Joint For Composites. Part B; Experimentation

    NASA Technical Reports Server (NTRS)

    Kostreva, Kristian M.

    2003-01-01

    Today, aerospace quality composite parts are generally made from either a unidirectional tape or a fabric prepreg form depending on the application. The matrix material, typically epoxy because of it dimensional stability, is pre-impregnated onto the fibers to ensure uniform distribution. Both of these composite forms are finding themselves used in applications where a joint is required. Two widely used joint methods are the classic mechanically fastened joint, and the contemporary bonded joint; however, the mechanically fastened joint is most commonly used by design engineers. A major portion of the research up-to-date about bolted composite joints has dealt with the inplane static load capacity. This work has helped to spawn standards dealing with filled-hole static joint strength. Other research has clearly shown that the clamp-up load in the mechanical fastener significantly affects the joint strength in a beneficial manner by reducing the bearing strength dependence of the composite laminate. One author reported a maximum increase in joint strength of 28%. This finding has helped to improve the reliability and efficiency of the joint in a composite structure.

  5. Obesity is not associated with increased knee joint torque and power during level walking.

    PubMed

    DeVita, Paul; Hortobágyi, Tibor

    2003-09-01

    While it is widely speculated that obesity causes increased loads on the knee leading to joint degeneration, this concept is untested. The purpose of the study was to identify the effects of obesity on lower extremity joint kinetics and energetics during walking. Twenty-one obese adults were tested at self-selected (1.29m/s) and standard speeds (1.50m/s) and 18 lean adults were tested at the standard speed. Motion analysis and force platform data were combined to calculate joint torques and powers during the stance phase of walking. Obese participants were more erect with 12% less knee flexion and 11% more ankle plantarflexion in self-selected compared to standard speeds (both p<0.02). Obese participants were still more erect than lean adults with approximately 6 degrees more extension at all joints (p<0.05, for each joint) at the standard speed. Knee and ankle torques were 17% and 11% higher (p<0.034 and p<0.041) and negative knee work and positive ankle work were 68% and 11% higher (p<0.000 and p<0.048) in obese participants at the standard speed compared to the slower speed. Joint torques and powers were statistically identical at the hip and knee but were 88% and 61% higher (both p<0.000) at the ankle in obese compared to lean participants at the standard speed. Obese participants used altered gait biomechanics and despite their greater weight, they had less knee torque and power at their self-selected walking speed and equal knee torque and power while walking at the same speed as lean individuals. We propose that the ability to reorganize neuromuscular function during gait may enable some obese individuals to maintain skeletal health of the knee joint and this ability may also be a more accurate risk indicator for knee osteoarthritis than body weight.

  6. The use of skeletal extension torque in reversing Dupuytren contractures of the proximal interphalangeal joint.

    PubMed

    Agee, John M; Goss, Ben C

    2012-07-01

    Dupuytren contracture of the proximal interphalangeal (PIP) joint can be reversed by an extension torque transmitted from an external device, the Digit Widget, by skeletal pins to the middle phalanx. This extension torque, generated by the same elastic bands dentists use to align teeth, gradually restores length to soft tissues palmar to the PIP joint's axis of rotation. Simultaneously, tissues dorsal to the joint's axis will shorten toward normal length as the PIP progressively straightens. Although the contractile nodules and bands of Dupuytren disease may be excised either before or after reversal of the joint's contracture, a 2-staged approach is preferred: (1) reverse the PIP flexion contracture, and (2) excise the diseased tissue from the straightened finger. We believe this 2-staged approach yields better results. In addition, it is technically easier to avoid injury to nerves and arteries while excising the nodules and bands, when one operates through palmar skin of more nearly normal length.

  7. Comparison of regression models for estimation of isometric wrist joint torques using surface electromyography

    PubMed Central

    2011-01-01

    Background Several regression models have been proposed for estimation of isometric joint torque using surface electromyography (SEMG) signals. Common issues related to torque estimation models are degradation of model accuracy with passage of time, electrode displacement, and alteration of limb posture. This work compares the performance of the most commonly used regression models under these circumstances, in order to assist researchers with identifying the most appropriate model for a specific biomedical application. Methods Eleven healthy volunteers participated in this study. A custom-built rig, equipped with a torque sensor, was used to measure isometric torque as each volunteer flexed and extended his wrist. SEMG signals from eight forearm muscles, in addition to wrist joint torque data were gathered during the experiment. Additional data were gathered one hour and twenty-four hours following the completion of the first data gathering session, for the purpose of evaluating the effects of passage of time and electrode displacement on accuracy of models. Acquired SEMG signals were filtered, rectified, normalized and then fed to models for training. Results It was shown that mean adjusted coefficient of determination (Ra2) values decrease between 20%-35% for different models after one hour while altering arm posture decreased mean Ra2 values between 64% to 74% for different models. Conclusions Model estimation accuracy drops significantly with passage of time, electrode displacement, and alteration of limb posture. Therefore model retraining is crucial for preserving estimation accuracy. Data resampling can significantly reduce model training time without losing estimation accuracy. Among the models compared, ordinary least squares linear regression model (OLS) was shown to have high isometric torque estimation accuracy combined with very short training times. PMID:21943179

  8. The effects of joint torque, pace and work:rest ratio on powered hand tool operations.

    PubMed

    Lin, Jia-Hua; McGorry, Raymond W; Maikala, Rammohan V

    2012-01-01

    Repetitive use of hand-held power tools is associated with work-related upper extremity musculoskeletal disorders. Using a pneumatic nutrunner, 21 men completed twelve 360 repetitive fastener-driving sessions on three joints (hard, soft and control) at slow and fast pace, and two different work:rest patterns. Handgrip force and perceived exertions were collected throughout each session. For the control joint, the mean grip force exerted was 39.6% of maximum voluntary exertion (MVE) whereas during hard and soft joint sessions it was 48.9% MVE and 56.9% MVE, respectively. Throughout each session, the grip force decreased, more while operating soft and hard joints as compared with the control joint (regression slope: -0.022 and -0.023, compared with -0.007 N/drive, respectively), suggesting considerable upper extremity muscular effort by participants during torque buildup. Fast work pace resulted in higher average grip forces by participants but a greater decrease in the force as the session progressed. Providing rest breaks reduced perceived exertions. The findings gain additional knowledge for assembly task design to possibly reduce the hand/arm injury risks for the operator. Practitioner Summary: Powered hand tools are widely used in assembly and manufacturing industries. However, the nature of their repetitive use on human operator biomechanical and perceptual responses is not fully understood. This study examined work-related risk factors such as joint torque, pace and work:rest ratios on powered hand tool performance.

  9. Intramuscular pressure and torque during isometric, concentric and eccentric muscular activity

    NASA Technical Reports Server (NTRS)

    Styf, J.; Ballard, R.; Aratow, M.; Crenshaw, A.; Watenpaugh, D.; Hargens, A. R.

    1995-01-01

    Intramuscular pressures, electromyography (EMG) and torque generation during isometric, concentric and eccentric maximal isokinetic muscle activity were recorded in 10 healthy volunteers. Pressure and EMG activity were continuously and simultaneously measured side by side in the tibialis anterior and soleus muscles. Ankle joint torque and position were monitored continuously by an isokinetic dynamometer during plantar flexion and dorsiflexion of the foot. The increased force generation during eccentric muscular activity, compared with other muscular activity, was not accompanied by higher intramuscular pressure. Thus, this study demonstrated that eccentric muscular activity generated higher torque values for each increment of intramuscular pressure. Intramuscular pressures during antagonistic co-activation were significantly higher in the tibilis anterior muscle (42-46% of maximal agonistic activity) compared with the soleus muscle (12-29% of maximal agonistic activity) and was largely due to active recruitment of muscle fibers. In summary, eccentric muscular activity creates higher torque values with no additional increase of the intramuscular pressure compared with concentric and isometric muscular activity.

  10. Changes in voluntary torque and electromyographic activity following oral baclofen.

    PubMed

    Hornby, T George; Heckman, C J; Harvey, Richard L; Rymer, W Zev

    2004-12-01

    The consequences of baclofen intake on voluntary motor behaviors remain unclear. We studied the effects of single oral doses of baclofen on voluntary, isometric knee extension torques and surface and single motor unit (MU) electromyographic (EMG) activity from the vastus lateralis in 11 individuals without neurological injury. Examination of submaximal to maximal contractions of varying duration performed pre- and post-baclofen ingestion revealed significant decreases in maximal knee torques and EMG magnitude, accompanied by an increase in slope of the torque-EMG relation. A decreased slope of the torque-MU firing rate relation was also demonstrated post-baclofen, but without changes in minimal firing rates or recruitment forces. During sustained contractions at < or =25% of maximal voluntary torque elicited after baclofen ingestion, increased EMG activity was observed without significant differences in MU firing rates. Our results demonstrate a clear reduction in the maximal torque-generating ability following baclofen. Specific changes in MU firing patterns indicate that weakness may be due partly to reduced motoneuronal excitability, although use of MU discharge patterns to assess these effects is limited in its sensitivity.

  11. Establishing a relationship between maximum torque production of isolated joints to simulate EVA ratchet push-pull maneuver: A case study

    NASA Technical Reports Server (NTRS)

    Pandya, Abhilash; Maida, James; Hasson, Scott; Greenisen, Michael; Woolford, Barbara

    1993-01-01

    As manned exploration of space continues, analytical evaluation of human strength characteristics is critical. These extraterrestrial environments will spawn issues of human performance which will impact the designs of tools, work spaces, and space vehicles. Computer modeling is an effective method of correlating human biomechanical and anthropometric data with models of space structures and human work spaces. The aim of this study is to provide biomechanical data from isolated joints to be utilized in a computer modeling system for calculating torque resulting from any upper extremity motions: in this study, the ratchet wrench push-pull operation (a typical extravehicular activity task). Established here are mathematical relationships used to calculate maximum torque production of isolated upper extremity joints. These relationships are a function of joint angle and joint velocity.

  12. A nonlinear tracking method of computing net joint torques for human movement.

    PubMed

    Seth, Ajay; Pandy, Marcus G

    2004-01-01

    Determining individual muscles forces from human performance has greatly depended on the quality of inverse dynamics solutions, as muscle force decomposition remains the only feasible approach for determining muscle forces non-invasively in human movement. However, legitimate questions about the accuracy of inverse dynamics arise, with resultant torques/forces failing to drive a forward model through the observations from which they were derived. While optimization of forward dynamics to match experimental data is considered more accurate, the simplicity and low computational costs of inverse methods are favored over the large computing requirements of optimization. In this paper, an evolution in the inverse methods for computing accurate and reliable torques is presented, whereby the relative speed of inverse dynamics is combined with the desired accuracy of forward dynamics. This method is based on developing a nonlinear tracker that determines the net muscle torques which accurately follow clinically observed kinematics and ground reaction forces. The results show that the method is robust and can produce accurate estimates of the joint torques during movement. The method outlined here is a necessary first step to solving the muscle force indeterminancy problem more efficiently.

  13. Applied Joint-Space Torque and Stiffness Control of Tendon-Driven Fingers

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E.; Platt, Robert, Jr.; Wampler, Charles W.; Hargrave, Brian

    2010-01-01

    Existing tendon-driven fingers have applied force control through independent tension controllers on each tendon, i.e. in the tendon-space. The coupled kinematics of the tendons, however, cause such controllers to exhibit a transient coupling in their response. This problem can be resolved by alternatively framing the controllers in the joint-space of the manipulator. This work presents a joint-space torque control law that demonstrates both a decoupled and significantly faster response than an equivalent tendon-space formulation. The law also demonstrates greater speed and robustness than comparable PI controllers. In addition, a tension distribution algorithm is presented here to allocate forces from the joints to the tendons. It allocates the tensions so that they satisfy both an upper and lower bound, and it does so without requiring linear programming or open-ended iterations. The control law and tension distribution algorithm are implemented on the robotic hand of Robonaut-2.

  14. Development of Torque Sensor with High Sensitivity for Joint of Robot Manipulator Using 4-Bar Linkage Shape

    PubMed Central

    Zhang, Hong-Xia; Ryoo, Young-Jae; Byun, Kyung-Seok

    2016-01-01

    The torque sensor is used to measure the joint torque of a robot manipulator. Previous research showed that the sensitivity and the stiffness of torque sensors have trade-off characteristics. Stiffness has to be sacrificed to increase the sensitivity of the sensor. In this research, a new torque sensor with high sensitivity (TSHS) is proposed in order to resolve this problem. The key idea of the TSHS comes from its 4-bar linkage shape in which the angular displacement of a short link is larger than that of a long link. The sensitivity of the torque sensor with a 4-bar link shape is improved without decreasing stiffness. Optimization techniques are applied to maximize the sensitivity of the sensor. An actual TSHS is constructed to verify the validity of the proposed mechanism. Experimental results show that the sensitivity of TSHS can be increased 3.5 times without sacrificing stiffness. PMID:27376304

  15. Note: Position/torque control of antagonistic robot joint with high-compliant twisted string actuators (TSAs).

    PubMed

    Park, Jihyuk; Kim, Ji-Chul; Kim, Kyung-Soo; Kim, Soohyun

    2016-12-01

    A tendon-driven robot joint that has a low inertia compared with a conventional drive system is proposed. The robot joint displaces the drive system toward the robot base, and it is driven by twisted string actuators (TSAs), which are a substitute for the conventional heavy drive system. The design of the proposed robot joint is based on an antagonistic scheme that is actuated by two motors. The torques from the motors are transmitted to the robot joint through the TSAs. Based on the geometric analysis of TSAs, strategies for position and torque control are proposed for an antagonistic robot joint driven by TSAs. To verify the proposed control strategies, several control experiments are conducted using a developed prototype of a robot joint.

  16. Torque Limit for Bolted Joint for Composites. Part A; TTTC Properties of Laminated Composites

    NASA Technical Reports Server (NTRS)

    Zhao, Yi

    2003-01-01

    The existing design code for torque limit of bolted joints for composites at Marshall Space Flight Center is MSFC-STD-486B, which was originally developed in 1960s for metallic materials. The theoretical basis for this code was a simplified mechanics analysis, which takes into account only the bolt, nut and washers, but not the structural members to be connected. The assumption was that metallic materials would not fail due to the bearing stress at the contact area between washer and the mechanical member. This is true for metallic materials; but for composite materials the results could be completely different. Unlike most metallic materials, laminated composite materials have superior mechanical properties (such as modulus and strength) in the in-plane direction, but not in the out-of-plane, or through-the-thickness (TTT) direction. During the torquing, TTT properties (particularly compressive modulus and compressive strength) play a dominant role in composite failure. Because of this concern, structural design engineers at Marshall are currently using a compromised empirical approach: using 50% of the torque value for composite members. Companies like Boeing is using a similar approach. An initial study was conducted last summer on this topic to develop theoretical model(s) that takes into consideration of composite members. Two simplified models were developed based on stress failure criterion and strain failure criterion, respective. However, these models could not be used to predict the torque limit because of the unavailability of material data, specifically, through-the-thickness compression (TTTC) modulus and strength. Therefore, the task for this summer is to experimentally determine the TTTC properties. Due to the time limitation, only one material has been tested: IM7/8552 with [0 degrees,plus or minus 45 degrees, 90 degree ] configuration. This report focuses the test results and their significance, while the experimentation will be described in a

  17. Effect of head contact on the rim of the cup on the offset loading and torque in hip joint replacement.

    PubMed

    Liu, Feng; Williams, Sophie; Jin, Zhongmin; Fisher, John

    2013-11-01

    Head contact on the rim of the cup causes stress concentration and consequently increased wear. The head contact on the rim of the cup may in addition cause an offset load and torque on the cup. The head-rim contact resulting from microseparation or subluxation has been investigated. An analytical model has been developed to calculate the offset loading and resultant torque on the cup as a function of the translational displacement of the head under simplified loading condition of the hip joint at heel strike during a walking cycle. The magnitude of the torque on the cup was found to increase with the increasing translational displacement, larger diameter heads, eccentric cups, and the coefficient of friction of the contact. The effects of cup inclination, cup rim radius, and cup coverage angle on the magnitude of the torque were found to be relatively small with a maximum variation in the torque magnitude being lower than 20%. This study has shown an increased torque due to the head loading on the rim of the cup, and this may contribute to the incidence of cup loosening. Particularly, metal-on-metal hip joints with larger head diameters may produce the highest offset loading torque.

  18. Effects of individual strengthening exercises for the stabilization muscles on the nutation torque of the sacroiliac joint in a sedentary worker with nonspecific sacroiliac joint pain.

    PubMed

    Yoo, Won-Gyu

    2015-01-01

    [Purpose] We investigated the effects of individual strengthening exercises for the stabilization muscles on the nutation torque of the sacroiliac joint in a sedentary worker with nonspecific sacroiliac joint pain. [Subject] A 36-year-old female complained of pain in the sacroiliac joints. [Methods] The subject performed individual strengthening exercises for the stabilization muscles for nutation torque of the sacroiliac joint for 3 weeks. Pain-provocation tests and visual analog scale (VAS) scores were evaluated before and after the exercises. [Results] After performing the individual strengthening exercises for the erector spinae, rectus abdominis, and biceps femoris muscles for 3 weeks, the subject displayed no pain in the pain provocation tests, and the VAS score was 2/10. [Conclusion] The individual strengthening exercises for the stabilization muscles of the sacroiliac joint performed in the present study appear to be effective for sedentary workers with sacroiliac joint pain.

  19. Effects of torque spring, CCL and latch mechanism on dynamic response of planar solar arrays with multiple clearance joints

    NASA Astrophysics Data System (ADS)

    Li, Yuanyuan; Wang, Zilu; Wang, Cong; Huang, Wenhu

    2017-03-01

    This paper numerically investigates the effects of torque spring, close cable loop (CCL) configuration and latch mechanism on the overall dynamic characteristics of a deployable solar arrays system considering joint clearance; and presents significant guidance for the key parameters design of these three mechanisms. A typical mechanism composed of a main-body with a yoke and two panels is used as a demonstration case to study the dynamic response of the deployable solar array system in the deployment process and post-latch phase. The normal contact force model and tangential friction model in clearance joint are established using nonlinear contact force model and modified Coulomb friction model, respectively. The numerical simulation results reveal that the joint clearances influence the dynamic characteristics of the deployable space solar arrays in different operation phases. Besides, parametric studies indicate some rules to design preload and stiffness coefficient of torque spring, equivalent stiffness coefficient of CCL mechanism and stiffness and damping coefficient of latch mechanism.

  20. Expertise-dependent modulation of muscular and non-muscular torques in multi-joint arm movements during piano keystroke.

    PubMed

    Furuya, S; Kinoshita, H

    2008-10-02

    The problem of skill-level-dependent modulation in the joint dynamics of multi-joint arm movements is addressed in this study using piano keystroke performed by expert and novice piano players. Using the measured kinematic and key-force data, the time varying net, gravitational, motion-dependent interaction (INT), key-reaction (REA), and muscular (MUS) torques at the shoulder, elbow, wrist, and metacarpophalangeal (MP) joints were computed using inverse dynamics techniques. INTs generated at the elbow and wrist joints, but not those at the MP joint, were greater for the experts as compared with the novices. REA at the MP joint, but not at the other joints, was less for the experts as compared with the novices. The MUSs at the MP, wrist, and elbow joints were smaller, and that at the shoulder joint was larger for the experts as compared with the novices. The experts also had a lesser inter-strike variability of key striking force and key descending velocity as compared with the novices. These findings indicated that the relationship among the INT, REA, and MUS occurring at the joints of the upper-extremity differed between the expert and novice piano players, suggesting that the organization of multi-joint arm movement is modulated by long-term motor training toward facilitating both physiological efficiency and movement accuracy.

  1. Estimations of relative effort during sit-to-stand increase when accounting for variations in maximum voluntary torque with joint angle and angular velocity.

    PubMed

    Bieryla, Kathleen A; Anderson, Dennis E; Madigan, Michael L

    2009-02-01

    The main purpose of this study was to compare three methods of determining relative effort during sit-to-stand (STS). Fourteen young (mean 19.6+/-SD 1.2 years old) and 17 older (61.7+/-5.5 years old) adults completed six STS trials at three speeds: slow, normal, and fast. Sagittal plane joint torques at the hip, knee, and ankle were calculated through inverse dynamics. Isometric and isokinetic maximum voluntary contractions (MVC) for the hip, knee, and ankle were collected and used for model parameters to predict the participant-specific maximum voluntary joint torque. Three different measures of relative effort were determined by normalizing STS joint torques to three different estimates of maximum voluntary torque. Relative effort at the hip, knee, and ankle were higher when accounting for variations in maximum voluntary torque with joint angle and angular velocity (hip=26.3+/-13.5%, knee=78.4+/-32.2%, ankle=27.9+/-14.1%) compared to methods which do not account for these variations (hip=23.5+/-11.7%, knee=51.7+/-15.0%, ankle=20.7+/-10.4%). At higher velocities, the difference in calculating relative effort with respect to isometric MVC or incorporating joint angle and angular velocity became more evident. Estimates of relative effort that account for the variations in maximum voluntary torque with joint angle and angular velocity may provide higher levels of accuracy compared to methods based on measurements of maximal isometric torques.

  2. Torque and Muscle Activation Impairment Along With Insulin Resistance Are Associated With Falls in Women With Fibromyalgia.

    PubMed

    Góes, Suelen M; Stefanello, Joice M F; Homann, Diogo; Lodovico, Angélica; Hubley-Kozey, Cheryl L; Rodacki, André L F

    2016-11-01

    Góes, SM, Stefanello, JMF, Homann, D, Lodovico, A, Hubley-Kozey, CL, and Rodacki, ALF. Torque and muscle activation impairment along with insulin resistance are associated with falls in women with fibromyalgia. J Strength Cond Res 30(11): 3155-3164, 2016-Fibromyalgia (FM) is a chronic pain condition associated with reduced muscle strength, which can lead to functional incapacity and higher risk of falls. The purpose of the study was to compare maximal ankle joint torque, muscle activation, and metabolic changes between women with and without FM. In addition, the relationship between those aspects and retrospectively reported falls in women with FM was determined. Twenty-nine middle-aged women with FM and 30 controls were recruited. Fall history, pain intensity, and pain threshold were assessed. Plasma glucose levels and insulin resistance (IR) were determined. Peak torque and rate of torque development (RTD) were calculated, and muscle activation was assessed from maximum isometric voluntary ankle dorsiflexion and plantar flexion contractions. In addition, voluntary muscle activation failure of the anterior tibialis muscle during maximal dorsiflexion was calculated. When compared to controls, women with FM reported higher number of retrospectively reported falls, exhibited higher IR, showed reduced plantar flexion and dorsiflexion RTD, had lower plantar flexion peak torque, and demonstrated more antagonist coactivation and higher muscle activation failure (p ≤ 0.05). Higher muscle activation failure was explained by glucose level and pain intensity (adj R = 0.28; p ≤ 0.05). Reduced plantar flexion and dorsiflexion peak torque explained 80% of retrospectively reported falls variance; also, high antagonist coactivation (odds ratio [OR] = 1.6; p ≤ 0.05) and high IR (OR = 1.8; p ≤ 0.05) increased the chance of falls in the FM group. A combination of metabolic factors and muscle function increased the odds of retrospectively reporting a fall in FM. Both aspects

  3. Linearizing the joint torque characteristics of an electric direct-drive robot for high performance control of in-contact operations

    SciTech Connect

    Muir, P.F.

    1992-01-01

    Many robot control algorithms for high performance in-contact operations including hybrid force/position, stiffness control and impedance control approaches require the command of the joint torques. However, most commercially available robots do not provide joint torque command capabilities. The joint command at the user level is typically position or velocity and at the control developer level is voltage current, or pulse-width, and the torque generated is a nonlinear function of the command and joint position. To enable the application of high performance in-contact control algorithms to commercially available robots, and thereby facilitate technology transfer from the robot control research community to commercial applications, a practical methodology has been developed to linearize the torque characteristics of electric motor-amplifier combinations. A four degree-of-freedom Adept 2 robot, having pulse-width modulation amplifiers and both variable reluctance and brushless DC motors, is converted to operate from joint torque commands to demonstrate the methodology. The average percentage torque deviation over the command and position ranges is reduced from as much as 76% to below 5% for the direct-drive joints 1, 2 and 4 and is cut by one half in the remaining ball-screw driven joint 3. 16 refs., 16 figs., 2 tabs.

  4. Effects of Low-Impact Dance on Blood Biochemistry, Bone Mineral Density, the Joint Range of Motion of Lower Extremities, Knee Extension Torque, and Fall in Females.

    PubMed

    Wu, Hui Ying; Tu, Jui Hung; Hsu, Chin Hsing; Tsao, Te Hung

    2016-01-01

    The effect of low-impact dance on blood metabolites, the joint range of motion (ROM) of the lower extremities, knee extension torque, bone mass density (BMD), the number of falls, and the confidence to perform daily activities (Modified Falls Efficacy Scale [MFES]) was examined in older sedentary women (age: 59 ± 4 years) before and after a 16-week intervention. Results showed that the average score for the MFES, some parameters of blood chemistry, and joint ROM were significantly improved after low-impact intervention. In addition to improvements in blood lipids and body fat percentages, the increases shown in the parameters regarding the lower extremities may contribute to confidence in performing common daily activities in older women, although the number of falls did not significantly differ between the two groups during the 16-week period.

  5. Torque-Limiting Infinitely-Variable CAM Release Mechanism for a Rotatable Joint

    NASA Technical Reports Server (NTRS)

    Moetteli, John B. (Inventor)

    1997-01-01

    The invention relates to a mechanism for permitting convenient manual or servo-powered control of a boom assembly, which is rotatably positionable about yaw and pitch axes by means of releasably locking, yaw and pitch torque-limiting mechanisms, each of which may be locked, unlocked, and positioned by respective yaw and pitch levers. The boom may be longitudinally projected and withdrawn by rotating a boom extension/retraction crank. Torque limiting is provided by spring loaded clutch mechanisms, whereby positioning forces applied to the handles are effective to move the boom unless overcome by greater opposing forces, sufficient to overcome the torque applied by the torque limiting clutch mechanisms. In operation, a structure positionable by the invention (e.g., and end-effector or robot arm) may be rotatably moved about yaw and pitch axes by moving a selected one of the three levers.

  6. Does sensorimotor cortex activity change with quadriceps femoris torque output? A human electroencephalography study.

    PubMed

    Fry, A; Vogt, T; Folland, J P

    2014-09-05

    Encoding muscular force output during voluntary contractions is widely perceived to result, at least in part, from modulations in neuronal activity within the sensorimotor cortex. However the underlying electrophysiological phenomena associated with increased force output remains unclear. This study directly assessed sensorimotor cortex activity using electroencephalography (EEG) in humans performing isometric knee-extensions at a range of discrete torque levels. Fifteen healthy males (age 24 (s=5) years) completed one familiarization and one experimental trial. Participants performed a cyclic series of 60 isometric knee-extension contractions with the right leg, including 15 contractions of a 5-s duration at each of four discrete torque levels: 15%, 30%, 45% and 60% of maximal voluntary torque (MVT). Isometric knee-extension torque, quadriceps electromyography and EEG were recorded at rest and throughout all the contractions. EEG (0.5-50 Hz) was collected using a 32-channel active-electrode cap. A voxel-based low-resolution brain electromagnetic tomography (LORETA) analysis calculated cortical activation within the sensorimotor cortex (one of 27 MNI coordinates) for the entire 0.5-50-Hz range (cortical current density (CCD)), as well as for each constituent frequency band in this range (delta, theta, alpha, beta and gamma). Gamma band (30-50 Hz) cortical activity increased with contraction torque (analysis of variance [ANOVA], P=0.03). Conversely, activity within the other frequency bands was not modulated by torque (P≥0.09), nor was overall CCD (P=0.11). Peripheral neuromuscular activation (quadriceps electromyography (EMG) amplitude) demonstrated distinct increases between each torque level (P<0.01). In conclusion, sensorimotor cortical activity within the gamma band demonstrated an overall increase with contraction torque, whereas both CCD and each of the other constituent frequency bands were not modulated by increments in torque magnitude during isometric

  7. Both the elongation of attached crossbridges and residual force enhancement contribute to joint torque enhancement by the stretch-shortening cycle

    PubMed Central

    Misaki, Jun; Isaka, Tadao

    2017-01-01

    This study examined the influence of the elongation of attached crossbridges and residual force enhancement on joint torque enhancement by the stretch-shortening cycle (SSC). Electrically evoked submaximal tetanic plantar flexions were adopted. Concentric contractions were evoked in the following three conditions: after 2 s isometric preactivation (ISO condition), after 1 s isometric then 1 s eccentric preactivation (ECC condition), and after 1 s eccentric then 1 s isometric preactivation (TRAN condition). Joint torque and fascicle length were measured during the concentric contraction phase. While no differences in fascicle length were observed among conditions at any time points, joint torque was significantly higher in the ECC than TRAN condition at the onset of concentric contraction. This difference would be caused by the dissipation of the elastic energy stored in the attached crossbridges induced by eccentric preactivation in TRAN condition due to 1 s transition phase. Furthermore, joint torques observed 0.3 and 0.6 s after concentric contraction were significantly larger in the ECC and TRAN conditions than in the ISO condition while no difference was observed between the ECC and TRAN conditions. Since the elastic energy stored in the attached crossbridges would have dissipated over this time frame, this result suggests that residual force enhancement induced by eccentric preactivation also contributes to joint torque enhancement by the SSC. PMID:28386453

  8. Influence of spin-transfer torque on thermally activated ferromagnetic resonance excitations in magnetic tunnel junctions

    NASA Astrophysics Data System (ADS)

    Petit, S.; de Mestier, N.; Baraduc, C.; Thirion, C.; Liu, Y.; Li, M.; Wang, P.; Dieny, B.

    2008-11-01

    Voltage noise measurements on magnetic tunnel junctions show that thermal fluctuations of the magnetization are either amplified or quenched by subcritical spin-transfer torque depending on the current direction. We present an analytical model that describes the dependence of thermally activated ferromagnetic resonance on bias current. The evolution of the peak amplitude and linewidth with the applied current is directly related to the longitudinal torque, whereas the shift of the resonance frequency is sensitive to the transverse torque. Both spin torque terms are independently extracted from the measured noise spectra. Our results support the general idea that it is more pertinent to describe spin torque in terms of voltage rather than current in magnetic tunnel junctions.

  9. Preparatory Body State before Reacting to an Opponent: Short-Term Joint Torque Fluctuation in Real-Time Competitive Sports.

    PubMed

    Fujii, Keisuke; Yamashita, Daichi; Kimura, Tetsuya; Isaka, Tadao; Kouzaki, Motoki

    2015-01-01

    In a competitive sport, the outcome of a game is determined by an athlete's relationship with an unpredictable and uncontrolled opponent. We have previously analyzed the preparatory state of ground reaction forces (GRFs) dividing non-weighted and weighted states (i.e., vertical GRFs below and above 120% of body weight, respectively) in a competitive ballgame task and demonstrated that the non-weighted state prevented delay of the defensive step and promoted successful guarding. However, the associated kinetics of lower extremity joints during a competitive sports task remains unknown. The present study aims to investigate the kinetic characteristics of a real-time competitive sport before movement initiation. As a first kinetic study on a competitive sport, we initially compared the successful defensive kinetics with a relatively stable preparatory state and the choice-reaction sidestep as a control movement. Then, we investigated the kinetic cause of the outcome in a 1-on-1 dribble in terms of the preparatory states according to our previous study. The results demonstrated that in successful defensive motions in the non-weighted state guarding trial, the times required for the generation of hip abduction and three extension torques for the hip, knee, and ankle joints were significantly shortened compared with the choice-reaction sidestep, and hip abduction and hip extension torques were produced almost simultaneously. The sport-specific movement kinetics emerges only in a more-realistic interactive experimental setting. A comparison of the outcomes in the 1-on-1 dribble and preparatory GRF states showed that, in the non-weighted state, the defenders guarded successfully in 68.0% of the trials, and the defender's initiation time was earlier than that in the weighted state (39.1%). In terms of kinetics, the root mean squares of the derivative of hip abduction and three extension torques in the non-weighted state were smaller than those in the weighted state

  10. The PHD: A Planar, Harmonic Drive Robot for Joint Torque Control

    DTIC Science & Technology

    1990-07-01

    Technical Report AI-TR 1072, August, 1989. [5] Eppinger, S.D. and Seering, W.P., "On Dynamic Models of Robot Force Control ", MIT Artificial... Robot Force Control ", Proceedings of the IEEE Conference on Robotics and Automation, April, 1985, Vol. 1, pp. 262- 268. 80 Appendix A: Torque Sensor

  11. Effects of submaximal eccentric exercise on muscle activity at different elbow joint angles.

    PubMed

    Kisiel-Sajewicz, Katarzyna; Jaskólska, Anna; Janecki, Damian; Andrzejewska, Renata; Marusiak, Jarosław; Jaskólski, Artur

    2014-01-01

    Our study aimed to determine whether electrical and mechanical factors contributing to acute or long-term maximal torque reduction and muscle soreness due to submaximal eccentric exercise (ECC) are elbow-joint-angle specific and to what extent the joint angle affects the contribution of antagonist coactivation to this torque reduction. Maximal isometric torque (MIT), muscle soreness assessment, agonist electromechanical activities, and antagonist coactivation during the maximal voluntary contraction (MVC) were measured at elbow joint angles of 60°, 90°, and 150° before ECC, immediately after exercise, and 24, 48, 72, and 120 hr after exercise. ECC causes an immediate decrease in MIT as well as increased antagonist coactivation at three angles. Antagonist coactivation returned to its baseline level at 24 hr regardless of joint angle. The most rapid torque recovery and the highest force level at which pain occurred were found after ECC at a joint angle of 60°. During the recovery period, no mechanomyographical changes were observed when measuring surface mechanomyography changes at three angles, while the electrical activity differed between angles.

  12. Active Joint Mechanism Driven by Multiple Actuators Made of Flexible Bags: A Proposal of Dual Structural Actuator

    PubMed Central

    Inou, Norio

    2013-01-01

    An actuator is required to change its speed and force depending on the situation. Using multiple actuators for one driving axis is one of the possible solutions; however, there is an associated problem of output power matching. This study proposes a new active joint mechanism using multiple actuators. Because the actuator is made of a flexible bag, it does not interfere with other actuators when it is depressurized. The proposed joint achieved coordinated motion of multiple actuators. This report also discusses a new actuator which has dual cylindrical structure. The cylinders are composed of flexible bags with different diameters. The joint torque is estimated based on the following factors: empirical formula for the flexible actuator torque, geometric relationship between the joint and the actuator, and the principle of virtual work. The prototype joint mechanism achieves coordinated motion of multiple actuators for one axis. With this motion, small inner actuator contributes high speed motion, whereas large outer actuator generates high torque. The performance of the prototype joint is examined by speed and torque measurements. The joint showed about 30% efficiency at 2.0 Nm load torque under 0.15 MPa air input. PMID:24385868

  13. Active joint mechanism driven by multiple actuators made of flexible bags: a proposal of dual structural actuator.

    PubMed

    Kimura, Hitoshi; Matsuzaki, Takuya; Kataoka, Mokutaro; Inou, Norio

    2013-01-01

    An actuator is required to change its speed and force depending on the situation. Using multiple actuators for one driving axis is one of the possible solutions; however, there is an associated problem of output power matching. This study proposes a new active joint mechanism using multiple actuators. Because the actuator is made of a flexible bag, it does not interfere with other actuators when it is depressurized. The proposed joint achieved coordinated motion of multiple actuators. This report also discusses a new actuator which has dual cylindrical structure. The cylinders are composed of flexible bags with different diameters. The joint torque is estimated based on the following factors: empirical formula for the flexible actuator torque, geometric relationship between the joint and the actuator, and the principle of virtual work. The prototype joint mechanism achieves coordinated motion of multiple actuators for one axis. With this motion, small inner actuator contributes high speed motion, whereas large outer actuator generates high torque. The performance of the prototype joint is examined by speed and torque measurements. The joint showed about 30% efficiency at 2.0 Nm load torque under 0.15 MPa air input.

  14. Effect of voluntary vs. artificial activation on the relationship of muscle torque to speed

    NASA Technical Reports Server (NTRS)

    Dudley, Gary A.; Harris, Robert T.; Duvoisin, Marc R.; Hather, Bruce M.; Buchanan, Paul

    1990-01-01

    The suggestion by Phillips and Petrofsky (1980) and Wickiewicz et al. (1984) that artificial activation of the knee extensor muscles should result in greater relative changes in torque than those evident with maximal voluntary activation is examined by investigating the speed-torque relationship of the right knee extensor muscle group in eight human subjects in whom activation was achieved by 'maximal' voluntary effort or by electrical stimulation. Torque was measured at a specific knee angle during isokinetic concentric or eccentric actions at velocities between 0.17 and 3.66 rad/s and during isometric actions. It is shown that, with artificial activation, the relative changes in both eccentric and concentric torque were greater as the speed increased; the speed-torque relationship was independed of the extent of activation and was similar to that of an isolated muscle. On the other hand, activation by the central nervous system during maximal effort depended on the speed and the type of muscle action performed.

  15. Impairment-Based 3-D Robotic Intervention Improves Upper Extremity Work Area in Chronic Stroke: Targeting Abnormal Joint Torque Coupling With Progressive Shoulder Abduction Loading

    PubMed Central

    Ellis, Michael D.; Sukal-Moulton, Theresa M.; Dewald, Julius P. A.

    2010-01-01

    The implementation of a robotic system (ACT3D) that allowed for a quantitative measurement of abnormal joint torque coupling in chronic stroke survivors and, most importantly, a quantitative means of initiating and progressing an impairment-based intervention, is described. Individuals with chronic moderate to severe stroke (n = 8) participated in this single-group pretest-posttest design study. Subjects were trained over eight weeks by progressively increasing the level of shoulder abduction loading experienced by the participant during reaching repetitions as performance improved. Reaching work area was evaluated pre- and postintervention for ten different shoulder abduction loading levels along with isometric single-joint strength and a qualitative clinical assessment of impairment. There was a significant effect of session (pre versus post) with an increase in reaching work area, despite no change in single-joint strength. This data suggests that specifically targeting the abnormal joint torque coupling impairment through progressive shoulder abduction loading is an effective strategy for improving reaching work area following hemiparetic stroke. Application of robotics, namely, the ACT3D, allowed for quantitative control of the exercise parameters needed to directly target the synergistic coupling impairment. The targeted reduction of abnormal joint torque coupling is likely the key factor explaining the improvements in reaching range of motion achieved with this intervention. PMID:20657711

  16. Reduced plantarflexor specific torque in the elderly is associated with a lower activation capacity.

    PubMed

    Morse, Christopher I; Thom, Jeanette M; Davis, Mark G; Fox, Ken R; Birch, Karen M; Narici, Marco V

    2004-06-01

    Previous studies have reported a decrease in muscle torque per cross-sectional area in old age. This investigation aimed at determining the influence of agonists muscle activation and antagonists co-activation on the specific torque of the plantarflexors (PF) in recreationally active elderly males (EM) and, for comparison, in young men (YM). Twenty-one EM, aged 70-82 years, and 14 YM, aged 19-35 years, performed isometric maximum voluntary contractions (MVC). Activation was assessed by comparing the amplitude of interpolated supramaximal twitch doublets at MVC, with post-tetanic doublet peak torque. Co-activation of the tibialis anterior (TA) was evaluated as the ratio of TA-integrated EMG (IEMG) activity during PF MVC compared to TA IEMG during maximal voluntary dorsiflexion. Triceps surae muscle volume (VOL) was assessed using magnetic resonance imaging (MRI), and PF peak torque was normalised to VOL (PT/VOL) since the later approximates physiological cross-sectional area (CSA) more closely than anatomical CSA. Also, physical activity level, assessed by accelerometry, was significantly lower (21%) in the elderly males. In comparison to the YM group, a greater difference in PT (39%) than VOL (19%) was found in the EM group. PT/VOL and activation capacity were respectively lower by 25% and 21% in EM compared to YM, whereas co-activation was not significantly different. In EM PT/VOL correlated with activation (R(2)=0.31, P<0.01). In conclusion, a reduction in activation capacity may contribute significantly to the decline in specific torque in the plantar flexors of elderly males. The hypothesis is put forward that reduced physical activity is partialy responsible for the reduced activation capacity in the elderly.

  17. Quantitative examinations for multi joint arm trajectory planning--using a robust calculation algorithm of the minimum commanded torque change trajectory.

    PubMed

    Wada, Y; Kaneko, Y; Nakano, E; Osu, R; Kawato, M

    2001-05-01

    In previous research, criteria based on optimal theories were examined to explain trajectory features in time and space in multi joint arm movement. Four criteria have been proposed. They were the minimum hand jerk criterion (by which a trajectory is planned in an extrinsic-kinematic space), the minimum angle jerk criterion (which is planned in an intrinsic-kinematic space), the minimum torque change criterion (where control objects are joint links; it is planned in an intrinsic-dynamic-mechanical space), and the minimum commanded torque change criterion (which is planned in an intrinsic space considering the arm and muscle dynamics). Which of these is proper as a criterion for trajectory planning in the central nervous system has been investigated by comparing predicted trajectories based on these criteria with previously measured trajectories. Optimal trajectories based on the two former criteria can be calculated analytically. In contrast, optimal trajectories based on the minimum commanded torque change criterion are difficult to be calculated, even with numerical methods. In some cases, they can be computed by a Newton-like method or a steepest descent method combined with a penalty method. However, for a realistic physical parameter range, the former becomes unstable quite often and the latter is unreliable about the optimality of the obtained solution. In this paper, we propose a new method to stably calculate optimal trajectories based on the minimum commanded torque change criterion. The method can obtain trajectories satisfying Euler-Poisson equations with a sufficiently high accuracy. In the method, a joint angle trajectory, which satisfies the boundary conditions strictly, is expressed by using orthogonal polynomials. The coefficients of the orthogonal polynomials are estimated by using a linear iterative calculation so as to satisfy the Euler-Poisson equations with a sufficiently high accuracy. In numerical experiments, we show that the optimal

  18. Suspending and Reinstating Joint Activities with Dialogue

    ERIC Educational Resources Information Center

    Chevalley, Eric; Bangerter, Adrian

    2010-01-01

    Interruptions are common in joint activities like conversations. Typically, interrupted participants suspend the activity, address the interruption, and then reinstate the activity. In conversation, people jointly commit to interact and to talk about a topic, establishing these commitments sequentially. When a commitment is suspended, face is…

  19. Thermally activated switching of perpendicular magnet by spin-orbit spin torque

    SciTech Connect

    Lee, Ki-Seung; Lee, Seo-Won; Min, Byoung-Chul; Lee, Kyung-Jin

    2014-02-17

    We theoretically investigate the threshold current for thermally activated switching of a perpendicular magnet by spin-orbit spin torque. Based on the Fokker-Planck equation, we obtain an analytic expression of the switching current, in agreement with numerical result. We find that thermal energy barrier exhibits a quasi-linear dependence on the current, resulting in an almost linear dependence of switching current on the log-scaled current pulse-width even below 10 ns. This is in stark contrast to standard spin torque switching, where thermal energy barrier has a quadratic dependence on the current and the switching current rapidly increases at short pulses. Our results will serve as a guideline to design and interpret switching experiments based on spin-orbit spin torque.

  20. Analysis of joint force and torque for the human and non-human ape foot during bipedal walking with implications for the evolution of the foot

    PubMed Central

    Wang, Weijie; Abboud, Rami J; Günther, Michael M; Crompton, Robin H

    2014-01-01

    The feet of apes have a different morphology from those of humans. Until now, it has merely been assumed that the morphology seen in humans must be adaptive for habitual bipedal walking, as the habitual use of bipedal walking is generally regarded as one of the most clear-cut differences between humans and apes. This study asks simply whether human skeletal proportions do actually enhance foot performance during human-like bipedalism, by examining the influence of foot proportions on force, torque and work in the foot joints during simulated bipedal walking. Skeletons of the common chimpanzee, orangutan, gorilla and human were represented by multi-rigid-body models, where the components of the foot make external contact via finite element surfaces. The models were driven by identical joint motion functions collected from experiments on human walking. Simulated contact forces between the ground and the foot were found to be reasonably comparable with measurements made during human walking using pressure- and force-platforms. Joint force, torque and work in the foot were then predicted. Within the limitations of our model, the results show that during simulated human-like bipedal walking, (1) the human and non-human ape (NHA) feet carry similar joint forces, although the distributions of the forces differ; (2) the NHA foot incurs larger joint torques than does the human foot, although the human foot has higher values in the first tarso-metatarsal and metatarso-phalangeal joints, whereas the NHA foot incurs higher values in the lateral digits; and (3) total work in the metatarso-phalangeal joints is lower in the human foot than in the NHA foot. The results indicate that human foot proportions are indeed well suited to performance in normal human walking. PMID:24925580

  1. A method to accurately estimate the muscular torques of human wearing exoskeletons by torque sensors.

    PubMed

    Hwang, Beomsoo; Jeon, Doyoung

    2015-04-09

    In exoskeletal robots, the quantification of the user's muscular effort is important to recognize the user's motion intentions and evaluate motor abilities. In this paper, we attempt to estimate users' muscular efforts accurately using joint torque sensor which contains the measurements of dynamic effect of human body such as the inertial, Coriolis, and gravitational torques as well as torque by active muscular effort. It is important to extract the dynamic effects of the user's limb accurately from the measured torque. The user's limb dynamics are formulated and a convenient method of identifying user-specific parameters is suggested for estimating the user's muscular torque in robotic exoskeletons. Experiments were carried out on a wheelchair-integrated lower limb exoskeleton, EXOwheel, which was equipped with torque sensors in the hip and knee joints. The proposed methods were evaluated by 10 healthy participants during body weight-supported gait training. The experimental results show that the torque sensors are to estimate the muscular torque accurately in cases of relaxed and activated muscle conditions.

  2. Within- and between-session reliability of the maximal voluntary knee extension torque and activation.

    PubMed

    Park, Jihong; Hopkins, J Ty

    2013-01-01

    A ratio between the torque generated by maximal voluntary isometric contraction (MVIC) and exogenous electrical stimulus, central activation ratio (CAR), has been widely used to assess quadriceps function. To date, no data exist regarding between-session reliability of this measurement. Thirteen neurologically sound volunteers underwent three testing sessions (three trials per session) with 48 hours between-session. Subjects performed MVICs of the quadriceps with the knee locked at 90° flexion and the hip at 85°. Once the MVIC reached a plateau, an electrical stimulation from superimposed burst technique (SIB: 125 V with peak output current 450 mA) was manually delivered and transmitted directly to the quadriceps via stimulating electrodes. CAR was calculated by using the following equation: CAR = MVIC torque/MVIC + SIB torque. Intraclass correlation coefficients (ICC) were calculated within- (ICC((2,1))) and between-session (ICC((2,k))) for MVIC torques and CAR values. Our data show that quadriceps MVIC and CAR are very reliable both within- (ICC((2,1)) = 0.99 for MVIC; 0.94 for CAR) and between-measurement sessions (ICC((2,k)) = 0.92 for MVIC; 0.86 for CAR) in healthy young adults. For clinical research, more data of the patients with pathological conditions are required to ensure reproducibility of calculation of CAR.

  3. Examination of the torque required to passively palmar abduct the thumb CMC joint in a pediatric population with hemiplegia and stroke.

    PubMed

    Stirling, Leia; Ahmad, Mona Qureshi; Kelty-Stephen, Damian; Correia, Annette

    2015-12-16

    Many activities of daily living involve precision grasping and bimanual manipulation, such as putting toothpaste on a toothbrush or feeding oneself. However, children afflicted by stroke, cerebral palsy, or traumatic brain injury may have lost or never had the ability to actively and accurately control the thumb. To translate insights from adult rehabilitation robotics to innovative therapies for hand rehabilitation in pediatric care, specifically for thumb deformities, an understanding of the torque needed to abduct the thumb to assist grasping tasks is required. Participants (n=16, 10 female, 13.2±3.1 years) had an upper extremity evaluation and measures were made of their passive range of motion, anthropometrics, and torques to abduct the thumb for both their affected and non-affected sides. Torque measures were made using a custom wrist orthosis that was adjusted for each participant. The torque to achieve maximum abduction was 1.47±0.61inlb for the non-affected side and 1.51±0.68inlb for the affected side, with a maximum recorded value of 4.87inlb. The overall maximum applied torque was observed during adduction and was 5.10inlb. We saw variation in the applied torque, which could have been due to the applied torques by the Occupational Therapist or the participant actively assisting or resisting the motion rather than remaining passive. We expect similar muscle and participant variation to exist with an assistive device. Thus, the data presented here can be used to inform the specifications for the development of an assistive thumb orthosis for children with "thumb-in-palm" deformity.

  4. The 2001 April Burst Activation of SGR 1900-14: Pulse Properties and Torque

    NASA Technical Reports Server (NTRS)

    Woods, P. M.; Kouveliotou, C.; Goegues, E.; Finger, M. H.; Feroci, M.; Mereghetti, S.; Swank, J. H.; Hurley, K.; Heise, J.; Smith D.

    2003-01-01

    We report on observations of SGR 1900+14 made with the Rossi X-Ray Timing Explorer (RXTE) and BeppoSAXduring the 2001 April burst activation of the source. Using these data, we measure the spin-down torque on the star and confirm earlier findings that the torque and burst activity are not directly correlated. We compare the X-ray pulse profile to the gamma-ray profile during the April 18 intermediate flare and show that (1) their shapes are similar and (1) the gamma-ray profile aligns closely in phase with the X-ray pulsations. The good phase alignment of the gamma-ray and X-ray profiles suggests that there was no rapid spin-down following this flare of the magnitude inferred for the August 27 giant flare. We discuss how these observations further constrain magnetic field reconfiguration models for the large flares of SGRs.

  5. Dynamics of the human head-neck system in the horizontal plane: joint properties with respect to a static torque.

    PubMed

    Tangorra, James L; Jones, Lynette A; Hunter, Ian W

    2003-05-01

    The vestibular system has often been studied by perturbing the position of the head. This study was conducted to identify the dynamic properties of the head-neck system in response to horizontal plane perturbations. A quasilinear approach was used to quantify the dynamics of the head-neck system at different levels of static torque. An operating point was established by applying a static torque to the head with a helmet-based perturber. The head-neck dynamics were then probed with a rich spectrum, stochastic, torque perturbation. Impulse response functions (IRFs) were estimated from correlation measures, and parametric models were fit to the IRFs. The results indicated that when the mean torque was held constant, the head-neck system behaved like a second-order, underdamped, passive system between 0.5 and 10.0 Hz. The system was not strictly linear, however. The properties of the system were sensitive to the static component of the torque. As the mean torque increased, the effective stiffness and damping progressively increased, and did so such that the system's damping ratio remained essentially constant. The findings of the study will assist in designing stimuli that are well tolerated by subjects and can induce head motions that span the performance capabilities of the vestibular system.

  6. Effect of Resistance Training Maintaining the Joint Angle-torque Profile Using a Haptic-based Machine on Shoulder Internal and External Rotation

    PubMed Central

    Kim, Yeonghun; Lee, Kunwoo; Moon, Jeheon; Koo, Dohoon; Park, Jaewoo; Kim, Kyengnam; Hong, Daehie; Shin, Inshik

    2014-01-01

    [Purpose] The aim of this study was to present an individualized resistance training method to enable exercise while maintaining an exercise load that is set according to an individual’s joint angle-torque using a haptic-based resistance training machine. [Methods] Five participants (machine group) performed individualized shoulder internal and external rotation training with a haptic resistance training machine, while another five participants performed general dumbbell-based shoulder internal and external rotation training for eight weeks. Internal and external rotation powers of subjects were measured using an isokinetic machine before and after training. [Results] The average powers of both shoulder internal and external rotation has been improved after training (25.72%, 13.62%). The improvement in power of external rotation in the machine group was significantly higher than that in the control group. [Conclusion] This study proposes a haptic-based individualized rotator cuff muscle training method. The training protocol maintaining the joint angle-torque profile showed better improvement of shoulder internal/external rotation than dumbbell training. PMID:24764626

  7. The 2001 April Burst Activation of SGR 1900+14: Pulse Properties and Torque

    NASA Technical Reports Server (NTRS)

    Woods, P. M.; Kouveliotou, C.; Goegues, E.; Finger, M. H.; Feroci, M.; Mereghetti, S.; Swank, J. H.; Hurley, K.; Heise, J.; Smith, D.; Six, N. Frank (Technical Monitor)

    2002-01-01

    We report on observations of SGR 1900+14 made with the Rossi X-ray Timing Explorer (RXTE) and BeppoSAX during the April 2001 burst activation of the source. Using these data, we measure the spindown torque on the star and confirm earlier findings that the torque and burst activity are not directly correlated. We compare the X-ray pulse profile to the gamma-ray profile during the April 18 intermediate flare and show that (i) their shapes are similar and (ii) the gamma-ray profile aligns closely in phase with the X-ray pulsations. The good phase alignment of the gamma-ray and X-ray profiles suggests that there was no rapid spindown following this flare, in contrast to the August 27 giant flare. The absence of rapid spindown in the hours following the April 18 flare suggests that there was no significant outflow of material as was believed to be present following the August 27 flare. Finally, we discuss how these observations further constrain magnetic field reconfiguration models for the large flares of SGRs.

  8. Quantifying anti-gravity torques for the design of a powered exoskeleton.

    PubMed

    Ragonesi, Daniel; Agrawal, Sunil K; Sample, Whitney; Rahman, Tariq

    2013-03-01

    Designing an upper extremity exoskeleton for people with arm weakness requires knowledge of the joint torques due to gravity and joint stiffness, as well as, active residual force capabilities of users. The objective of this research paper is to describe the characteristics of the upper limb of children with upper limb impairment. This paper describes the experimental measurements of the torque on the upper limb due to gravity and joint stiffness of three groups of subjects: able-bodied adults, able-bodied children, and children with neuromuscular disabilities. The experiment involves moving the arm to various positions in the sagittal plane and measuring the resultant force at the forearm. This force is then converted to torques at the elbow and shoulder. These data are compared to a two-link lumped mass model based on anthropomorphic data. Results show that the torques based on anthropometry deviate from experimentally measured torques as the arm goes through the range. Subjects with disabilities also maximally pushed and pulled against the force sensor to measure maximum strength as a function of arm orientation. For all subjects, the maximum voluntary applied torque at the shoulder and elbow in the sagittal plane was found to be lower than gravity torques throughout the disabled subjects' range of motion. This experiment informs designers of upper limb orthoses on the contribution of passive human joint torques due to gravity and joint stiffness and the strength capability of targeted users.

  9. A Study of a Handrim-Activated Power-Assist Wheelchair Based on a Non-Contact Torque Sensor

    PubMed Central

    Nam, Ki-Tae; Jang, Dae-Jin; Kim, Yong Chol; Heo, Yoon; Hong, Eung-Pyo

    2016-01-01

    Demand for wheelchairs is increasing with growing numbers of aged and disabled persons. Manual wheelchairs are the most commonly used assistive device for mobility because they are convenient to transport. Manual wheelchairs have several advantages but are not easy to use for the elderly or those who lack muscular strength. Therefore, handrim-activated power-assist wheelchairs (HAPAW) that can aid driving power with a motor by detecting user driving intentions through the handrim are being researched. This research will be on HAPAW that judge user driving intentions by using non-contact torque sensors. To deliver the desired motion, which is sensed from handrim rotation relative to a fixed controller, a new driving wheel mechanism is designed by applying a non-contact torque sensor, and corresponding torques are simulated. Torques are measured by a driving wheel prototype and compared with simulation results. The HAPAW prototype was developed using the wheels and a driving control algorithm that uses left and right input torques and time differences are used to check if the non-contact torque sensor can distinguish users’ driving intentions. Through this procedure, it was confirmed that the proposed sensor can be used effectively in HAPAW. PMID:27509508

  10. Diffusion of active particles with stochastic torques modeled as α-stable noise

    NASA Astrophysics Data System (ADS)

    Nötel, Jörg; Sokolov, Igor M.; Schimansky-Geier, Lutz

    2017-01-01

    We investigate the stochastic dynamics of an active particle moving at a constant speed under the influence of a fluctuating torque. In our model the angular velocity is generated by a constant torque and random fluctuations described as a Lévy-stable noise. Two situations are investigated. First, we study white Lévy noise where the constant speed and the angular noise generate a persistent motion characterized by the persistence time {τ }D. At this time scale the crossover from ballistic to normal diffusive behavior is observed. The corresponding diffusion coefficient can be obtained analytically for the whole class of symmetric α-stable noises. As typical for models with noise-driven angular dynamics, the diffusion coefficient depends non-monotonously on the angular noise intensity. As second example, we study angular noise as described by an Ornstein-Uhlenbeck process with correlation time {τ }c driven by the Cauchy white noise. We discuss the asymptotic diffusive properties of this model and obtain the same analytical expression for the diffusion coefficient as in the first case which is thus independent on {τ }c. Remarkably, for {τ }c\\gt {τ }D the crossover from a non-Gaussian to a Gaussian distribution of displacements takes place at a time {τ }G which can be considerably larger than the persistence time {τ }D.

  11. Inductance and Active Phase Vector Based Torque Control for Switched Reluctance Motor Drives.

    NASA Astrophysics Data System (ADS)

    Kalpathi, Ramani Raman

    The Switched Reluctance Motor (SRM) drive technology has developed significantly over the last few years. The simplicity in both motor design and power converter requirement along with the availability of high frequency, high power semiconductor switches have made SRMs compete with conventional adjustable speed drive technologies. The subject of winding current control in switched reluctance machines has always been associated with the shaft position information. The use of inductance for direct commutation control is the central subject of this dissertation. In contrast to the conventional methods based on position commutation, new methods of control based on inductance commutation are presented. The object of a commutation algorithm is to switch the currents in the phase coils, in order to provide continuous energy conversion with maximum torque output for a given unit of input current. Since torque production in a SRM is based on the concept of variable reluctance, it makes more sense to observe the instantaneous phase inductance or reluctance instead of estimating the rotor position. The inductance sensors observe the machine parameters and provide sufficient information on the electrical characteristics of the coils. This control strategy avoids the inductance to position transformation blocks conventionally used in SRM control systems. In a typical SRM, the phase coils have a nonlinear behavior of inductance due to effects of current saturation. Also the parameters of one phase coil differ from those of the other due to manufacturing tolerances or due to bearing wear. In such cases, the algorithms written during the stage of manufacturing may not be valid after parameter changes. Optimizing torque production in the event of phase asymmetry and saturation is developed in this research. Indirect sensors connected to the active phase coil of the SRM are based on sensing the flux level in the active coil. New commutation algorithms based on flux sensing concepts

  12. Hex ball torque test

    NASA Technical Reports Server (NTRS)

    Robinson, B. A.; Foster, C. L.

    1986-01-01

    A series of torque tests were performed on four flight-type hex ball universal joints in order to characterize and determine the actual load-carrying capability of this device. The universal joint is a part of manual actuation rods for scientific instruments within the Hubble Space Telescope. It was found that the hex ball will bind slightly during the initial load application. This binding did not affect the function of the universal joint, and the units would wear-in after a few additional loading cycles. The torsional yield load was approximately 50 ft-lb, and was consistent among the four test specimens. Also, the torque required to cause complete failure exceeded 80 ft-lb. It is concluded that the hex ball universal joint is suitable for its intended applications.

  13. Reduced elbow extension torque during vibrations.

    PubMed

    Friesenbichler, Bernd; Coza, Aurel; Nigg, Benno M

    2012-08-31

    Impact sports and vibration platforms trigger vibrations within soft tissues and the skeleton. Although the long-term effects of vibrations on the body have been studied extensively, the acute effects of vibrations are little understood. This study determined the influence of acute vibrations at different frequencies and elbow angles on maximal isometric elbow extension torque and muscle activity. Vibrations were generated by a pneumatic vibrator attached to the lever of a dynamometer, and were applied on the forearm of 15 healthy female subjects. The subjects were instructed to push maximally against the lever at three different elbow angles, while extension torque and muscle activity were quantified and compared between vibration and non-vibration (control) conditions. A change in vibration frequency had no significant effects on torque and muscle activity although vibrations in general decreased the maximal extension torque relative to the control by 1.8% (±5.7%, p>0.05), 7.4% (±7.9%, p<0.01), and 5.0% (±8.2%, p<0.01) at elbow angles of 60°, 90°, and 120°, respectively. Electromyographic activity increased significantly between ∼30% and 40% in both triceps and biceps with vibrations. It is speculated that a similar increase in muscle activity between agonist and antagonist, in combination with an unequal increase in muscle moment arms about the elbow joint, limit the maximal extension torque during exposure to vibrations. This study showed that maximal extension torque decreased during vibration exposure while muscle activity increased and suggests that vibrations may be counterproductive during activities requiring maximal strength but potentially beneficial for strength training.

  14. Muscle enhancement using closed-loop electrical stimulation: volitional versus induced torque.

    PubMed

    Langzam, E; Nemirovsky, Y; Isakov, E; Mizrahi, J

    2007-06-01

    In cases of partial deficiency of muscle activation capacity, force augmentation can be achieved by hybrid activation, i.e., by combining electrical stimulation (ES) with volitional activation. In this activation modality the shares of the volitional and induced torques within the overall hybrid torque are unknown. The purpose of this study was to suggest a computational approach to parcel out the volitional and stimulation induced components of joint torque generated during combined voluntary and electrical activation of the Tibialis Anterior muscle (TA). For this purpose, isometric contraction of the TA was studied on 5 healthy subjects, using an activation protocol involving ES alone, volitional activation alone and hybrid activation. Ankle torque and TA EMG were measured. A computational algorithm was developed to dissociate the volitional from the overall torque, based on EMG filtering and on pre-measured calibration curves of volitional torque versus EMG. The results indicated that for a certain hybrid torque there is a linear decaying relationship between the induced torque and the volitional torque shares. Moreover, based on a defined enhancement ratio, the results indicate that within the range of stimulation intensities, there exist regions of increased facilitation, in which the stimulation efficiency is higher under combined compared to isolated conditions.

  15. Elimination of Harmonic Force and Torque in Active Magnetic Bearing Systems with Repetitive Control and Notch Filters.

    PubMed

    Xu, Xiangbo; Chen, Shao; Liu, Jinhao

    2017-04-04

    Harmonic force and torque, which are caused by rotor imbalance and sensor runout, are the dominant disturbances in active magnetic bearing (AMB) systems. To eliminate the harmonic force and torque, a novel control method based on repetitive control and notch filters is proposed. Firstly, the dynamics of a four radial degrees of freedom AMB system is described, and the AMB model can be described in terms of the translational and rotational motions, respectively. Next, a closed-loop generalized notch filter is utilized to identify the synchronous displacement resulting from the rotor imbalance, and a feed-forward compensation of the synchronous force and torque related to the AMB displacement stiffness is formulated by using the identified synchronous displacement. Then, a plug-in repetitive controller is designed to track the synchronous feed-forward compensation adaptively and to suppress the harmonic vibrations due to the sensor runout. Finally, the proposed control method is verified by simulations and experiments. The control algorithm is insensitive to the parameter variations of the power amplifiers and can precisely suppress the harmonic force and torque. Its practicality stems from its low computational load.

  16. Active chaotic excitation for bolted joint monitoring

    NASA Astrophysics Data System (ADS)

    Fasel, Timothy R.; Todd, Michael D.; Park, Gyuhae

    2006-03-01

    Recent research has shown that high frequency chaotic excitation and state space reconstruction may be used to identify incipient damage (loss of preload) in a bolted joint. In this study, a new experiment is undertaken with updated test equipment, including a piezostack actuator that allows for precise control of bolt preload. The excitation waveform is applied to a macro-fiber composite (MFC) patch that is bonded to the test structure and is sensed in an active manner using a second MFC patch. A novel prediction error algorithm, based on comparing filtered properties of the guided chaotic waves, is used to determine the damage state of a frame structure and is shown to be highly sensitive to small levels of bolt preload loss. The performance of the prediction error method is compared with standard structural health monitoring damage features that are based on time series analysis using auto-regressive (AR) models.

  17. Evaluation of force-torque displays for use with space station telerobotic activities

    NASA Technical Reports Server (NTRS)

    Hendrich, Robert C.; Bierschwale, John M.; Manahan, Meera K.; Stuart, Mark A.; Legendre, A. Jay

    1992-01-01

    Recent experiments which addressed Space Station remote manipulation tasks found that tactile force feedback (reflecting forces and torques encountered at the end-effector through the manipulator hand controller) does not improve performance significantly. Subjective response from astronaut and non-astronaut test subjects indicated that force information, provided visually, could be useful. No research exists which specifically investigates methods of presenting force-torque information visually. This experiment was designed to evaluate seven different visual force-torque displays which were found in an informal telephone survey. The displays were prototyped in the HyperCard programming environment. In a within-subjects experiment, 14 subjects nullified forces and torques presented statically, using response buttons located at the bottom of the screen. Dependent measures included questionnaire data, errors, and response time. Subjective data generally demonstrate that subjects rated variations of pseudo-perspective displays consistently better than bar graph and digital displays. Subjects commented that the bar graph and digital displays could be used, but were not compatible with using hand controllers. Quantitative data show similar trends to the subjective data, except that the bar graph and digital displays both provided good performance, perhaps do to the mapping of response buttons to display elements. Results indicate that for this set of displays, the pseudo-perspective displays generally represent a more intuitive format for presenting force-torque information.

  18. The role of interaction torque and muscle torque in the control of downward squatting.

    PubMed

    Fujisawa, Hiroyuki; Suzuki, Hiroto; Murakami, Kenichi; Kawakami, Shingo; Suzuki, Makoto

    2016-01-01

    [Purpose] The purposes of this study were first to analyze the multijoint dynamics of downward squatting, and to examine the contribution of interaction torque and muscle torque to net torque, and second, to examine mechanisms of movement control. [Subjects] The subjects were 31 healthy men with a mean age of 21.0 ± 1.2 years (range, 19-24 years). [Methods] Squatting tasks with the trunk in two positions, an erect and anterior tilt position, were performed by the subjects. Net, interaction, muscle, and gravity torque were calculated according to the Lagrange equation using 3D tracking data. [Results] The contribution ratio of interaction torque to net torque was approximately 90%, irrespective of the joint and task. In contrast, muscle torque showed complicated behavior to compensate for gravity torque. A combined muscle and gravity torque profile showed flexion or dorsiflexion immediately after the initiation of the movement, and it later changed to extension or plantar flexion. [Conclusion] The torque that contributes almost exclusively to the net torque was interaction torque. The combination of muscle and gravity torque at the knee joint and the hip joint is important for movement control, independent of the starting position.

  19. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles.

    PubMed

    Serefoglu, Abdullah; Sekir, Ufuk; Gür, Hakan; Akova, Bedrettin

    2017-03-01

    The aim of this study was to investigate if static and dynamic stretching exercises of the knee muscles (quadriceps and hamstring muscles) have any effects on concentric and eccentric isokinetic peak torques and electromyographic amplitudes (EMG) of the antagonist muscles. Twenty healthy male athletes (age between 18-30 years) voluntarily participated in this study. All of the subjects visited the laboratory to complete the following intervention in a randomized order on 5 separate days; (a) non-stretching (control), (b) static stretching of the quadriceps muscles, (c) static stretching of the hamstring muscles, (d) dynamic stretching of the quadriceps muscles, and (e) dynamic stretching of the hamstring muscles. Static stretching exercises either for the quadriceps or the hamstring muscles were carried out at the standing and sitting positions. Subjects performed four successive repetitions of each stretching exercises for 30 seconds in both stretching positions. Similar to static stretching exercises two different stretching modes were designed for dynamic stretching exercises. Concentric and eccentric isokinetic peak torque for the non-stretched antagonist quadriceps or hamstring muscles at angular velocities of 60°/sec and 240°/sec and their concurrent electromyographic (EMG) activities were measured before and immediately after the intervention. Isokinetic peak torques of the non-stretched agonist hamstring and quadriceps muscles did not represent any significant (p > 0.05) differences following static and dynamic stretching of the antagonist quadriceps and hamstring muscles, respectively. Similarly, the EMG activities of the agonist muscles exhibited no significant alterations (p > 0.05) following both stretching exercises of the antagonist muscles. According to the results of the present study it is possible to state that antagonist stretching exercises either in the static or dynamic modes do not affect the isokinetic peak torques and the EMG activities

  20. Application of computational lower extremity model to investigate different muscle activities and joint force patterns in knee osteoarthritis patients during walking.

    PubMed

    Nha, Kyung Wook; Dorj, Ariunzaya; Feng, Jun; Shin, Jun Ho; Kim, Jong In; Kwon, Jae Ho; Kim, Kyungsoo; Kim, Yoon Hyuk

    2013-01-01

    Many experimental and computational studies have reported that osteoarthritis in the knee joint affects knee biomechanics, including joint kinematics, joint contact forces, and muscle activities, due to functional restriction and disability. In this study, differences in muscle activities and joint force patterns between knee osteoarthritis (OA) patients and normal subjects during walking were investigated using the inverse dynamic analysis with a lower extremity musculoskeletal model. Extensor/flexor muscle activations and torque ratios and the joint contact forces were compared between the OA and normal groups. The OA patients had higher extensor muscle forces and lateral component of the knee joint force than normal subjects as well as force and torque ratios of extensor and flexor muscles, while the other parameters had little differences. The results explained that OA patients increased the level of antagonistic cocontraction and the adduction moment on the knee joint. The presented findings and technologies provide insight into biomechanical changes in OA patients and can also be used to evaluate the postoperative functional outcomes of the OA treatments.

  1. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles

    PubMed Central

    Serefoglu, Abdullah; Sekir, Ufuk; Gür, Hakan; Akova, Bedrettin

    2017-01-01

    The aim of this study was to investigate if static and dynamic stretching exercises of the knee muscles (quadriceps and hamstring muscles) have any effects on concentric and eccentric isokinetic peak torques and electromyographic amplitudes (EMG) of the antagonist muscles. Twenty healthy male athletes (age between 18-30 years) voluntarily participated in this study. All of the subjects visited the laboratory to complete the following intervention in a randomized order on 5 separate days; (a) non-stretching (control), (b) static stretching of the quadriceps muscles, (c) static stretching of the hamstring muscles, (d) dynamic stretching of the quadriceps muscles, and (e) dynamic stretching of the hamstring muscles. Static stretching exercises either for the quadriceps or the hamstring muscles were carried out at the standing and sitting positions. Subjects performed four successive repetitions of each stretching exercises for 30 seconds in both stretching positions. Similar to static stretching exercises two different stretching modes were designed for dynamic stretching exercises. Concentric and eccentric isokinetic peak torque for the non-stretched antagonist quadriceps or hamstring muscles at angular velocities of 60°/sec and 240°/sec and their concurrent electromyographic (EMG) activities were measured before and immediately after the intervention. Isokinetic peak torques of the non-stretched agonist hamstring and quadriceps muscles did not represent any significant (p > 0.05) differences following static and dynamic stretching of the antagonist quadriceps and hamstring muscles, respectively. Similarly, the EMG activities of the agonist muscles exhibited no significant alterations (p > 0.05) following both stretching exercises of the antagonist muscles. According to the results of the present study it is possible to state that antagonist stretching exercises either in the static or dynamic modes do not affect the isokinetic peak torques and the EMG activities

  2. Active Power Control of Wind Turbines for Ancillary Services: A Comparison of Pitch and Torque Control Methodologies

    SciTech Connect

    Aho, Jacob; Fleming, Paul; Pao, Lucy Y.

    2016-08-01

    As wind energy generation becomes more prevalent in some regions, there is increased demand for wind power plants to provide ancillary services, which are essential for grid reliability. This paper compares two different wind turbine control methodologies to provide active power control (APC) ancillary services, which include derating or curtailing power generation, providing automatic generation control (AGC), and providing primary frequency control (PFC). The torque APC controller provides all power control through the power electronics whereas the pitch APC controller uses the blade pitch actuators as the primary means of power control. These controllers are simulated under various wind conditions with different derating set points and AGC participation levels. The metrics used to compare their performance are the damage equivalent loads (DELs) induced on the structural components and AGC performance metrics, which are used to determine the payments for AGC services by system operators in the United States. The simulation results show that derating the turbine reduces structural loads for both control methods, with the APC pitch control providing larger reductions in DELs, lower AGC performance scores, and higher root-mean-square pitch rates. Providing AGC increases the structural loads when compared to only derating the turbine, but even the AGC DELs are generally lower than those of the baseline control system. The torque APC control methodology also allows for more sustained PFC responses under certain derating conditions.

  3. Characterization of the torque limits and clamping force relationships for small stainless steel screws in tensile loaded joints of various metals

    SciTech Connect

    Bernardin, John D; Flores, Eugene M

    2009-01-01

    This study originated during the design of ChemCam, a Laser Induced Breakdown Spectroscopy (LIBS) and imaging instrument being developed for NASA's Mars Science Lab Rover. The mission needs for miniaturization, reduced weight, high reliability, minimal use of thread locking compounds, and the ability to handle harsh environmental conditions dictated the use of small, high strength screws to be threaded into a variety of metal alloys including Be-S200f, Al-6061-T6, Mg-ZK60A-T5, and Ti-6Al-4V The lack of a credible fastener torque database for small (No.0 through No.8) high strength stainless steel screws in various parent materials, led to the development of an experimental program to characterize the following: (A) The screw torque value versus angular rotation (which indicates yielding in the screw or parent material) as a function of screw diameter, screw head configuration, depth of thread engagement, type of parent material, type of surface treatment on parent material, presence of thread locking compound, repeatable threaded hole use, and degree of screw pedigree. (B) The relationship between fastener torque and clamping force for a subset of the above mentioned variables. The database generated from this study will serve as a design reference for utilizing small stainless steel fasteners and provide trending information for other researchers who may be interested in broadening its range of parameters. This paper reviews the related fastener torque and clamping force information from the literature, describes the experimental screw torque and clamping force monitoring equipment, presents the test matrix and experimental procedures, and discusses the empirical results.

  4. Improved computed torque control for industrial robots

    NASA Technical Reports Server (NTRS)

    Uebel, Mark; Minis, Ioannis; Cleary, Kevin

    1992-01-01

    The authors examine the computed torque control problem for a robot arm with flexible, geared, joint drive systems which are typical in many industrial robots. The standard computed torque algorithm is not directly applicable to this class of manipulators due to the dynamics introduced by the joint drive systems. The proposed approach overcomes this problem by combining a novel computed torque algorithm with simple torque controllers at each joint of the robot. The control scheme is applied to a seven degree-of-freedom industrial manipulator, and the system performance in standard tasks is evaluated using both dynamic simulation and actual experiments. The results show that the proposed controller leads to improved tracking performance over a conventional PD (proportional plus derivative) controller.

  5. Contraction type influences the human ability to use the available torque capacity of skeletal muscle during explosive efforts.

    PubMed

    Tillin, Neale A; Pain, Matthew T G; Folland, Jonathan P

    2012-06-07

    The influence of contraction type on the human ability to use the torque capacity of skeletal muscle during explosive efforts has not been documented. Fourteen male participants completed explosive voluntary contractions of the knee extensors in four separate conditions: concentric (CON) and eccentric (ECC); and isometric at two knee angles (101°, ISO101 and 155°, ISO155). In each condition, torque was measured at 25 ms intervals up to 150 ms from torque onset, and then normalized to the maximum voluntary torque (MVT) specific to that joint angle and angular velocity. Explosive voluntary torque after 50 ms in each condition was also expressed as a percentage of torque generated after 50 ms during a supramaximal 300 Hz electrically evoked octet in the same condition. Explosive voluntary torque normalized to MVT was more than 60 per cent larger in CON than any other condition after the initial 25 ms. The percentage of evoked torque expressed after 50 ms of the explosive voluntary contractions was also greatest in CON (ANOVA; p < 0.001), suggesting higher concentric volitional activation. This was confirmed by greater agonist electromyography normalized to M(max) (recorded during the explosive voluntary contractions) in CON. These results provide novel evidence that the ability to use the muscle's torque capacity explosively is influenced by contraction type, with concentric contractions being more conducive to explosive performance due to a more effective neural strategy.

  6. Contraction type influences the human ability to use the available torque capacity of skeletal muscle during explosive efforts

    PubMed Central

    Tillin, Neale A.; Pain, Matthew T. G.; Folland, Jonathan P.

    2012-01-01

    The influence of contraction type on the human ability to use the torque capacity of skeletal muscle during explosive efforts has not been documented. Fourteen male participants completed explosive voluntary contractions of the knee extensors in four separate conditions: concentric (CON) and eccentric (ECC); and isometric at two knee angles (101°, ISO101 and 155°, ISO155). In each condition, torque was measured at 25 ms intervals up to 150 ms from torque onset, and then normalized to the maximum voluntary torque (MVT) specific to that joint angle and angular velocity. Explosive voluntary torque after 50 ms in each condition was also expressed as a percentage of torque generated after 50 ms during a supramaximal 300 Hz electrically evoked octet in the same condition. Explosive voluntary torque normalized to MVT was more than 60 per cent larger in CON than any other condition after the initial 25 ms. The percentage of evoked torque expressed after 50 ms of the explosive voluntary contractions was also greatest in CON (ANOVA; p < 0.001), suggesting higher concentric volitional activation. This was confirmed by greater agonist electromyography normalized to Mmax (recorded during the explosive voluntary contractions) in CON. These results provide novel evidence that the ability to use the muscle's torque capacity explosively is influenced by contraction type, with concentric contractions being more conducive to explosive performance due to a more effective neural strategy. PMID:22258636

  7. Spacesuit mobility knee joints

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C. (Inventor)

    1979-01-01

    Pressure suit mobility joints are for use in interconnecting adjacent segments of an hermetically sealed spacesuit in which low torques, low leakage and a high degree of reliability are required. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics and includes linkages which restrain the joint from longitudinal distension and includes a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

  8. Spacesuit mobility joints

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C. (Inventor)

    1978-01-01

    Joints for use in interconnecting adjacent segments of an hermetically sealed spacesuit which have low torques, low leakage and a high degree of reliability are described. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics. Linkages which restrain the joint from longitudinal distension and a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli are featured. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

  9. DOD-DOE Workshop on Joint Energy Activities

    SciTech Connect

    1980-01-01

    The general conditions for DOD-DOE interactions were delineated in an October 1978, Memorandum of Understanding (MOU) that identified two basic goals: improving energy efficiency and availability within DOD, and utilizing DOD and DOE expertise and facilities to carry out projects of mutual interest. There has been considerable interaction between DOD and DOE, including a number of proposed joint initiatives but a systematic and coordinated approach for nurturing, maintaining, and expanding these relationships has not been developed. A DOD-DOE Workshop on Joint Energy Activities was held on March 10-12, 1980. The workshop was structured into five working groups - Mobility Fuels, Conservation, Fossil Fuels for Fixed Facilities, Solar and Renewable Energy Sources, and Special Projects - with DOD and DOE cochairmen for each. Over a hundred DOD and DOE management, program, and policymaking representatives were brought together by the workshop Steering Committee to identify specific programs for inclusion in an overall plan for implementing the MOU and to deal with fundamental issues and problems of maintaining future communications. The workshop accomplished its goals, these being to: (1) improve communication among the appropriate key DOD and DOE personnel at all levels and promote information exchange; (2) review ongoing and already-proposed joint DOD and DOE programs; (3) initiate a coordinated, systematic effort to establish joint DOD-DOE energy-security programs; and (4) propose specific programs and projects of mutual interest for inclusion in a follow-on joint-implementation plan.

  10. Active Design Method for the Static Characteristics of a Piezoelectric Six-Axis Force/Torque Sensor

    PubMed Central

    Liu, Jun; Li, Min; Qin, Lan; Liu, Jingcheng

    2014-01-01

    To address the bottleneck issues of an elastic-style six-axis force/torque sensor (six-axis force sensor), this work proposes a no-elastic piezoelectric six-axis force sensor. The operating principle of the piezoelectric six-axis force sensor is analyzed, and a structural model is constructed. The static-active design theory of the piezoelectric six-axis force sensor is established, including a static analytical/mathematical model and numerical simulation model (finite element model). A piezoelectric six-axis force sensor experimental prototype is developed according to the analytical mathematical model and numerical simulation model, and selected static characteristic parameters (including sensitivity, isotropic degree and cross-coupling) are tested using this model with three approaches. The measured results are in agreement with the analytical results from the static-active design method. Therefore, this study has successfully established a foundation for further research into the piezoelectric multi-axis force sensor and an overall design approach based on static characteristics. PMID:24451460

  11. Serum prolidase activity in benign joint hypermobility syndrome

    PubMed Central

    2014-01-01

    Background Moderate joint laxity is widespread in many joints of the body, and this condition is considered to be caused by an abnormality in the collagen structure. This study was carried out to determine the serum prolidase activity in female patients with benign joint hypermobility syndrome (BJHS), and to evaluate its correlation with their clinical features. Methods A total of 45 patients with BJHS and 40 healthy controls were included in the study. All of the patients with BJHS met the Beighton diagnostic criteria. All the patients and the control group underwent a comprehensive examination of the locomotor system and took the New York Posture Rating Test. The examination and test results were recorded. Serum prolidase activity was measured in both the groups. Results Prolidase activity was significantly lower in patients with BJHS (479.52 ± 126.50) compared to the healthy controls (555.97 ± 128.77) (p = 0.007). We found no correlation between serum prolidase activity and Beighton scores or New York rating test scores. On the other hand, mean prolidase activity was significantly lower in patients with pes planus or hyperlordosis compared to those without (p = 0.05, p = 0.03, respectively). We did not find such a correlation with the other clinical features. Conclusions Significantly lower prolidase activity in patients with BJHS suggests that prolidase may affect the collagen metabolism and cause hyperlaxity. PMID:24612543

  12. Construction and biological activity of a full-length molecular clone of human Torque teno virus (TTV) genotype 6.

    PubMed

    Kakkola, Laura; Tommiska, Johanna; Boele, Linda C L; Miettinen, Simo; Blom, Tea; Kekarainen, Tuija; Qiu, Jianming; Pintel, David; Hoeben, Rob C; Hedman, Klaus; Söderlund-Venermo, Maria

    2007-09-01

    Torque teno virus (TTV) is a non-enveloped human virus with a circular negative-sense (approximately 3800 nucleotides) ssDNA genome. TTV resembles in genome organization the chicken anemia virus, the animal pathogen of the Circoviridae family, and is currently classified as a member of a new, floating genus, Anellovirus. Molecular and cell biological research on TTV has been restricted by the lack of permissive cell lines and functional, replication-competent plasmid clones. In order to examine the key biological activities (i.e. RNA transcription and DNA replication) of this still poorly characterized ssDNA virus, we cloned the full-length genome of TTV genotype 6 and transfected it into cells of several types. TTV mRNA transcription was detected by RT-PCR in all the cell types: KU812Ep6, Cos-1, 293, 293T, Chang liver, Huh7 and UT7/Epo-S1. Replicating TTV DNA was detected in the latter five cell types by a DpnI-based restriction enzyme method coupled with Southern analysis, a novel approach to assess TTV DNA replication. The replicating full-length clone, the cell lines found to support TTV replication, and the methods presented here will facilitate the elucidation of the molecular biology and the life cycle of this recently identified human virus.

  13. Torque resolver design for tendon-driven manipulators

    SciTech Connect

    Lee, J.J.; Tsai, Lung-Wen

    1992-08-01

    Given a set of desired joint torques in an n-DOF tendon-driven manipulator with n + 1 control tendons, the determination of tendon forces is an indeterminate problem. Usually, the pseudo-inverse technique is used to solve for such a problem. In this paper, rather than using the pseudo-inverse technique is used to solve for such a problem. In this paper, rather than using the pseudo-inverse technique, an efficient methodology for transforming joint torques (n elements) to motor torques (n + 1 elements) has been developed. This technique called ``torque resolver``, utilizes two circuit-like operators to transform torques between the two different vector spaces. It can be easily programmed on a digital computer or implemented into an analog-circuit system. It is hoped that this technique will make real-time computed-torque control feasible. The technique has been demonstrated through the dynamic simulation of a three-DOF manipulator.

  14. Torque resolver design for tendon-driven manipulators

    SciTech Connect

    Lee, J.J.; Tsai, Lung-Wen.

    1992-01-01

    Given a set of desired joint torques in an n-DOF tendon-driven manipulator with n + 1 control tendons, the determination of tendon forces is an indeterminate problem. Usually, the pseudo-inverse technique is used to solve for such a problem. In this paper, rather than using the pseudo-inverse technique is used to solve for such a problem. In this paper, rather than using the pseudo-inverse technique, an efficient methodology for transforming joint torques (n elements) to motor torques (n + 1 elements) has been developed. This technique called torque resolver'', utilizes two circuit-like operators to transform torques between the two different vector spaces. It can be easily programmed on a digital computer or implemented into an analog-circuit system. It is hoped that this technique will make real-time computed-torque control feasible. The technique has been demonstrated through the dynamic simulation of a three-DOF manipulator.

  15. Effects of series elasticity on the human knee extension torque-angle relationship in vivo.

    PubMed

    Kubo, Keitaro; Ohgo, Kazuya; Takeishi, Ryuichi; Yoshinaga, Kazunari; Tsunoda, Naoya; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2006-12-01

    The purpose of this study was to investigate the effects of series elasticity on the torque-angle relationship of the knee extensors in vivo. Forty-two men volunteered to take part in the present study. The participants performed maximal voluntary isometric contractions at eight knee-joint angles (40, 50, 60, 70, 80, 90, 100, 110 degrees). The elongation of the tendon and aponeurosis of the vastus lateralis muscle was directly measured by ultrasonography, while the participants performed ramp isometric knee extensions to the voluntary maximum at 800 of knee angle. There was no significant difference in the torque value between 50 degrees and 100 degrees, although there was variation in the shape of the "torque-angle" relationship. The variability in the torque-angle curve was not affected by the activation level of agonist and antagonist muscles and the moment arm length. The ratio of torque at 1000 compared to that at 50 degrees was significantly (r(2) = 18-23 %) correlated to the maximal elongation and strain (to initial length) of the tendon structures. These results suggest that increased compliance of tendon structures of the knee extensors may contribute to variations in the torque-angle curves of the knee extensors.

  16. Torque patterns of the limbs of small therian mammals during locomotion on flat ground.

    PubMed

    Witte, Hartmut; Biltzinger, Jutta; Hackert, Rémi; Schilling, Nadja; Schmidt, Manuela; Reich, Christian; Fischer, Martin S

    2002-05-01

    In three species of small therian mammals (Scandentia: Tupaia glis, Rodentia: Galea musteloides and Lagomorpha: Ochotona rufescens) the net joint forces and torques acting during stance phase in the four kinematically relevant joints of the forelimbs (scapular pivot, shoulder joint, elbow joint, wrist joint) and the hindlimbs (hip joint, knee joint, ankle joint, intratarsal joint) were determined by inverse dynamic analysis. Kinematics were measured by cineradiography (150 frames s(-1)). Synchronously ground reaction forces were acquired by forceplates. Morphometry of the extremities was performed by a scanning method using structured illumination. The vector sum of ground reaction forces and weight accounts for most of the joint force vector. Inertial effects can be neglected since errors of net joint forces amount at most to 10 %. The general time course of joint torques is comparable for all species in all joints of the forelimb and in the ankle joint. Torques in the intratarsal joints differ between tailed and tail-less species. The torque patterns in the knee and hip joint are unique to each species. For the first time torque patterns are described completely for the forelimb including the scapula as the dominant propulsive segment. The results are compared with the few torque data available for various joints of cats (Felis catus), dogs (Canis lupus f. familiaris), goats (Capra sp.) and horses (Equus przewalskii f. caballus).

  17. Decoding tactile afferent activity to obtain an estimate of instantaneous force and torque applied to the fingerpad.

    PubMed

    Khamis, Heba; Birznieks, Ingvars; Redmond, Stephen J

    2015-07-01

    Dexterous manipulation is not possible without sensory information about object properties and manipulative forces. Fundamental neuroscience has been unable to demonstrate how information about multiple stimulus parameters may be continuously extracted, concurrently, from a population of tactile afferents. This is the first study to demonstrate this, using spike trains recorded from tactile afferents innervating the monkey fingerpad. A multiple-regression model, requiring no a priori knowledge of stimulus-onset times or stimulus combination, was developed to obtain continuous estimates of instantaneous force and torque. The stimuli consisted of a normal-force ramp (to a plateau of 1.8, 2.2, or 2.5 N), on top of which -3.5, -2.0, 0, +2.0, or +3.5 mNm torque was applied about the normal to the skin surface. The model inputs were sliding windows of binned spike counts recorded from each afferent. Models were trained and tested by 15-fold cross-validation to estimate instantaneous normal force and torque over the entire stimulation period. With the use of the spike trains from 58 slow-adapting type I and 25 fast-adapting type I afferents, the instantaneous normal force and torque could be estimated with small error. This study demonstrated that instantaneous force and torque parameters could be reliably extracted from a small number of tactile afferent responses in a real-time fashion with stimulus combinations that the model had not been exposed to during training. Analysis of the model weights may reveal how interactions between stimulus parameters could be disentangled for complex population responses and could be used to test neurophysiologically relevant hypotheses about encoding mechanisms.

  18. Torque Limits for Fasteners in Composites

    NASA Technical Reports Server (NTRS)

    Zhao, Yi

    2002-01-01

    The two major classes of laminate joints are bonded and bolted. Often the two classes are combined as bonded-bolted joints. Several characteristics of fiber reinforced composite materials render them more susceptible to joint problems than conventional metals. These characteristics include weakness in in-plane shear, transverse tension/compression, interlaminar shear, and bearing strength relative to the strength and stiffness in the fiber direction. Studies on bolted joints of composite materials have been focused on joining assembly subject to in-plane loads. Modes of failure under these loading conditions are net-tension failure, cleavage tension failure, shear-out failure, bearing failure, etc. Although the studies of torque load can be found in literature, they mainly discussed the effect of the torque load on in-plane strength. Existing methods for calculating torque limit for a mechanical fastener do not consider connecting members. The concern that a composite member could be crushed by a preload inspired the initiation of this study. The purpose is to develop a fundamental knowledge base on how to determine a torque limit when a composite member is taken into account. Two simplified analytical models were used: a stress failure analysis model based on maximum stress criterion, and a strain failure analysis model based on maximum strain criterion.

  19. Effect of Preactivation on Torque Enhancement by the Stretch-Shortening Cycle in Knee Extensors

    PubMed Central

    Fukutani, Atsuki; Misaki, Jun; Isaka, Tadao

    2016-01-01

    The stretch-shortening cycle is one of the most interesting topics in the field of sport sciences, because the performance of human movement is enhanced by the stretch-shortening cycle (eccentric contraction). The purpose of the present study was to examine whether the influence of preactivation on the torque enhancement by stretch-shortening cycle in knee extensors. Twelve men participated in this study. The following three conditions were conducted for knee extensors: (1) concentric contraction without preactivation (CON), (2) concentric contraction with eccentric preactivation (ECC), and (3) concentric contraction with isometric preactivation (ISO). Muscle contractions were evoked by electrical stimulation to discard the influence of neural activity. The range of motion of the knee joint was set from 80 to 140 degrees (full extension = 180 degrees). Angular velocities of the concentric and eccentric contractions were set at 180 and 90 degrees/s, respectively. In the concentric contraction phase, joint torques were recorded at 85, 95, and 105 degrees, and they were compared among the three conditions. In the early phase (85 degrees) of concentric contraction, the joint torque was larger in the ECC and ISO conditions than in the CON condition. However, these clear differences disappeared in the later phase (105 degrees) of concentric contraction. The results showed that joint torque was clearly different among the three conditions in the early phase whereas this difference disappeared in the later phase. Thus, preactivation, which is prominent in the early phase of contractions, plays an important role in torque enhancement by the stretch-shortening cycle in knee extensors. PMID:27414804

  20. Shoulder Joint For Protective Suit

    NASA Technical Reports Server (NTRS)

    Kosmo, Joseph J.; Smallcombe, Richard D.

    1994-01-01

    Shoulder joint allows full range of natural motion: wearer senses little or no resisting force or torque. Developed for space suit, joint offers advantages in protective garments for underwater work, firefighting, or cleanup of hazardous materials.

  1. Nociceptive nerve activity in an experimental model of knee joint osteoarthritis of the guinea pig: effect of intra-articular hyaluronan application.

    PubMed

    Gomis, Ana; Miralles, Ana; Schmidt, Robert F; Belmonte, Carlos

    2007-07-01

    Nociceptive impulse activity was recorded extracellularly from single A delta and C primary afferents of the guinea pig's medial articular nerve after induction of an experimental osteoarthritis in the knee joint by partial medial menisectomy and transection of the anterior cruciate ligament (PMM+TACL). Also, the analgesic effects of intra-articular hyaluronan solutions were evaluated. Healthy, PMM+TACL operated, sham-operated (opening of the joint capsule without PMM and TACL surgery) and acutely inflamed (intra-articular kaolin-carrageenan, K-C) animals were used. The stimulus protocol consisted of torque meter-controlled, standardized innocuous and noxious inward and outward rotations of the joint. This stimulus protocol of 50 s duration was repeated every 5 min for 70 min. One day, one week and three weeks after PMM+TACL, the movement-evoked discharges of A delta articular afferents were increased significantly over values found in sham-operated animals. The discharges of C fibers were significantly augmented only one week after PMM+TACL surgery. Filling of the joint cavity with a high viscosity hyaluronan solution (hylan G-F 20, Synvisc) immediately and three days after surgery reduced significantly the enhanced nerve activity observed in joint afferent fibers one day and one week after surgery. Augmentation of movement-evoked discharges in K-C acutely inflamed knee joints was similar to that observed one week after PMM+TACL. Our results indicate that in the PMM+TACL model of osteoarthritis in guinea pigs, enhancement of nociceptive responses to joint movement was primarily associated to post-surgical inflammation. Intra-articular injection of an elastoviscous hyaluronan solution reduced the augmented nerve activity.

  2. Methodology for Determining Limit Torques for Threaded Fasteners

    NASA Technical Reports Server (NTRS)

    Hissam, Andy

    2011-01-01

    In aerospace design, where minimizing weight is always a priority, achieving the full capacity from fasteners is essential. To do so, the initial bolt preload must be maximized. The benefits of high preload are well documented and include improved fatigue resistance, a stiffer joint, and resistance to loosening. But many factors like elastic interactions and embedment tend to lower the initial preload placed on the bolt. These factors provide additional motivation to maximize the initial preload. But, to maximize bolt preload, you must determine what torque to apply. Determining this torque is greatly complicated by the large preload scatter generally seen with torque control. This paper presents a detailed methodology for generating limit torques for threaded fasteners. This methodology accounts for the large scatter in preload found with torque control, and therefore, addresses the statistical nature of the problem. It also addresses prevailing torque, a feature common in aerospace fasteners. Although prevailing torque provides a desired locking feature, it can also increase preload scatter. In addition, it can limit the amount of preload that can be generated due to the torsion it creates in the bolt. This paper discusses the complications of prevailing torque and how best to handle it. A wide range of torque-tension bolt testing was conducted in support of this research. The results from this research will benefit the design engineer as well as analyst involved in the design of bolted joints, leading to better, more optimized structural designs.

  3. Cortical and corticospinal output modulations during reaching movements with varying directions and magnitudes of interaction torques.

    PubMed

    Asmussen, M J; Bailey, A Z; Nelson, A J

    2015-12-17

    The neural command required to coordinate a multi-joint movement is inherently complex. During multi-joint movement of the limb, the force created from movement at one joint may create a torque at a second joint known as an interaction torque. Interaction torques may be assistive or resistive thereby aiding or opposing the motion of the second joint, respectively. For movement to be effectively controlled, the central nervous system should modulate neural output to the muscles to appropriately account for interaction torques. The present study examined the neural output from the primary motor cortex before and during reaching movements that required different combinations of assistive and resistive interaction torques occurring at the shoulder and elbow joints. Using transcranial magnetic stimulation to probe neural output from the primary motor cortex, results indicate that corticospinal output controlling the upper arm is related to resistive interaction torques occurring at the shoulder joint. Further, cortical output to bi-articular muscles is associated with interaction torque and this may be driven by the fact that these muscles are in an advantageous position to control torques produced between inter-connection segments. Humans have a tendency to avoid reaching movements that involve resistive interaction torques and this may be driven by the requirement of increased neural output associated with these movements.

  4. Angle- and gender-specific quadriceps femoris muscle recruitment and knee extensor torque.

    PubMed

    Pincivero, Danny M; Salfetnikov, Yuliya; Campy, Robert M; Coelho, Alan J

    2004-11-01

    The objectives were to examine knee angle-, and gender-specific knee extensor torque output and quadriceps femoris (QF) muscle recruitment during maximal effort, voluntary contractions. Fourteen young adult men and 15 young adult women performed three isometric maximal voluntary contractions (MVC), in a random order, with the knee at 0 degrees (terminal extension), 10 degrees, 30 degrees, 50 degrees, 70 degrees, and 90 degrees flexion. Knee extensor peak torque (PT), and average torque (AT) were expressed in absolute (N m), relative (N m kg(-1)) and allometric-modeled (N m kg(-n)) units. Vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscle EMG signals were full-wave rectified and integrated over the middle 3 s of each contraction, averaged over the three trials at each knee angle, and normalized to the activity recorded at 0 degrees. Muscle recruitment efficiency was calculated as the ratio of the normalized EMG of each muscle to the allometric-modeled average torque (normalized to the values at 0 degrees flexion), and expressed as a percent. Men generated significantly greater knee extensor PT and AT than women in absolute, relative and allometric-modeled units. Absolute and relative PT and AT were significantly highest at 70 degrees, while allometric-modeled values were observed to increase significantly across knee joint angles 10-90 degrees. VM EMG was significantly greater than the VL and RF muscles across all angles, and followed a similar pattern to absolute knee extensor torque. Recruitment efficiency improved across knee joint angles 10-90 degrees and was highest for the VL muscle. VM recruitment efficiency improved more than the VL and RF muscles across 70-90 degrees flexion. The findings demonstrate angle-, and gender-specific responses of knee extensor torque to maximal-effort contractions, while superficial QF muscle recruitment was most efficient at 90 degrees, and less dependent on gender.

  5. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  6. Joint amplitude and frequency analysis of tremor activity.

    PubMed

    Foerster, F; Smeja, M

    1999-01-01

    Clinical tremor analysis mostly is used for the measurement of tremor frequency. The analysis is based on short segments of EMG recordings and on clinical ratings of tremor intensity. Accelerometry appears to have some practical advantages. The present study was concerned with the development of a methodology for assessing tremor activity using the three parameters, frequency (Hz), amplitude (g), and occurrence of tremor (in per cent of time). These parameters were derived from joint amplitude frequency analysis of the calibrated accelerometer raw signal and from appropriate decision rules. This methodology was used in connection with 27 patients with Parkinson's disease, to investigate the aforesaid parameters of tremor activity. Postural tremor had a higher occurrence time (right-hand only) and higher frequency (left-hand only) than resting tremor, however, the average amplitudes did not differ. The correlations between right-hand and left-hand measures were higher during postural tremor test. Frequency was not correlated to amplitude or occurrence time, however, moderate correlations did exist between amplitude and occurrence time. In addition to the assessment of tremor activity, multi-channel accelerometry may be used for the detection of posture and motion. Further applications of this methodology, for example, in 24 hr ambulatory monitoring of tremor, are discussed.

  7. van der Waals torque

    NASA Astrophysics Data System (ADS)

    Esquivel-Sirvent, Raul; Schatz, George

    2014-03-01

    The theory of generalized van der Waals forces by Lifshtz when applied to optically anisotropic media predicts the existence of a torque. In this work we present a theoretical calculation of the van der Waals torque for two systems. First we consider two isotropic parallel plates where the anisotropy is induced using an external magnetic field. The anisotropy will in turn induce a torque. As a case study we consider III-IV semiconductors such as InSb that can support magneto plasmons. The calculations of the torque are done in the Voigt configuration, that occurs when the magnetic field is parallel to the surface of the slabs. The change in the dielectric function as the magnetic field increases has the effect of decreasing the van der Waals force and increasing the torque. Thus, the external magnetic field is used to tune both the force and torque. The second example we present is the use of the torque in the non retarded regime to align arrays of nano particle slabs. The torque is calculated within Barash and Ginzburg formalism in the nonretarded limit, and is quantified by the introduction of a Hamaker torque constant. Calculations are conducted between anisotropic slabs of materials including BaTiO3 and arrays of Ag nano particles. Depending on the shape and arrangement of the Ag nano particles the effective dielectric function of the array can be tuned as to make it more or less anisotropic. We show how this torque can be used in self assembly of arrays of nano particles. ref. R. Esquivel-Sirvent, G. C. Schatz, Phys. Chem C, 117, 5492 (2013). partial support from DGAPA-UNAM.

  8. EMG-Torque correction on Human Upper extremity using Evolutionary Computation

    NASA Astrophysics Data System (ADS)

    JL, Veronica; Parasuraman, S.; Khan, M. K. A. Ahamed; Jeba DSingh, Kingsly

    2016-09-01

    There have been many studies indicating that control system of rehabilitative robot plays an important role in determining the outcome of the therapy process. Existing works have done the prediction of feedback signal in the controller based on the kinematics parameters and EMG readings of upper limb's skeletal system. Kinematics and kinetics based control signal system is developed by reading the output of the sensors such as position sensor, orientation sensor and F/T (Force/Torque) sensor and there readings are to be compared with the preceding measurement to decide on the amount of assistive force. There are also other works that incorporated the kinematics parameters to calculate the kinetics parameters via formulation and pre-defined assumptions. Nevertheless, these types of control signals analyze the movement of the upper limb only based on the movement of the upper joints. They do not anticipate the possibility of muscle plasticity. The focus of the paper is to make use of the kinematics parameters and EMG readings of skeletal system to predict the individual torque of upper extremity's joints. The surface EMG signals are fed into different mathematical models so that these data can be trained through Genetic Algorithm (GA) to find the best correlation between EMG signals and torques acting on the upper limb's joints. The estimated torque attained from the mathematical models is called simulated output. The simulated output will then be compared with the actual individual joint which is calculated based on the real time kinematics parameters of the upper movement of the skeleton when the muscle cells are activated. The findings from this contribution are extended into the development of the active control signal based controller for rehabilitation robot.

  9. Pelvic rotation torque during fast-pitch softball hitting under three ball height conditions.

    PubMed

    Iino, Yoichi; Fukushima, Atsushi; Kojima, Takeji

    2014-08-01

    The purpose of this study was to investigate the relevance of hip joint angles to the production of the pelvic rotation torque in fast-pitch softball hitting and to examine the effect of ball height on this production. Thirteen advanced female softball players hit stationary balls at three different heights: high, middle, and low. The pelvic rotation torque, defined as the torque acting on the pelvis through the hip joints about the pelvic superior-inferior axis, was determined from the kinematic and force plate data using inverse dynamics. Irrespective of the ball heights, the rear hip extension, rear hip external rotation, front hip adduction, and front hip flexion torques contributed to the production of pelvic rotation torque. Although the contributions of the adduction and external rotation torques at each hip joint were significantly different among the ball heights, the contributions of the front and rear hip joint torques were similar among the three ball heights owing to cancelation of the two torque components. The timings of the peaks of the hip joint torque components were significantly different, suggesting that softball hitters may need to adjust the timings of the torque exertions fairly precisely to rotate the upper body effectively.

  10. Bevel gear driver and method having torque limit selection

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1994-01-01

    This invention comprises a torque drive mechanism utilizing axially translatable, mutually engageable transmission members having mating crown gears, driven and driving members with a three-element drive train being biased together by resilient means or by a fluid actuator system, the apparatus being operable to transmit a precisely controlled degree of torque to a driven member. The apparatus is applicable for use in hand tools and as a replacement for impact torque drivers, torque wrenches, motorized screw drivers, or the like, wherein the applied torque must be precisely controlled or limited. The bevel torque drive includes a drive gear which is axially displaceable and rotatable within cylindrical driver housing, a rotatable intermediate gear, and an output gear. Key rotationally secures displaceable gear with respect to input shaft but permits axial movement therebetween. A thrust bearing is preferably connected to the lower end of shaft for support to reduce play and friction between shaft and a transmission joint disc during rotation of the gear train. Coaxially mounted coiled spring is footed against displaceable gear for biasing the displaceable gear toward and into engagement with the intermediate gear for driving intermediate gear and output gear. Torque control is achieved by the use of straight or spiral beveled gears which are of configurations adapted to withdraw from mutual engagement upon the torque exceeding a predetermined limit. The novel, advantageous features of the invention include the configuration of the mating, crown gear sets and the axially translatable, slidable drive gear. The mechanism is capable of transmitting a high degree of torque within a narrow, compact transmission housing. The compact size and narrow, elongated configuration of the housing is particularly applicable for use in hand tools and in multiple torque driver mechanisms in which it is necessary to drive multiple fasteners which are located in close proximity. Prior

  11. AX-5 space suit bearing torque investigation

    NASA Technical Reports Server (NTRS)

    Loewenthal, Stuart; Vykukal, Vic; Mackendrick, Robert; Culbertson, Philip, Jr.

    1990-01-01

    The symptoms and eventual resolution of a torque increase problem occurring with ball bearings in the joints of the AX-5 space suit are described. Starting torques that rose 5 to 10 times initial levels were observed in crew evaluation tests of the suit in a zero-g water tank. This bearing problem was identified as a blocking torque anomaly, observed previously in oscillatory gimbal bearings. A large matrix of lubricants, ball separator designs and materials were evaluated. None of these combinations showed sufficient tolerance to lubricant washout when repeatedly cycled in water. The problem was resolved by retrofitting a pressure compensated, water exclusion seal to the outboard side of the bearing cavity. The symptoms and possible remedies to blocking are discussed.

  12. Experimental Observations for Determining the Maximum Torque Values to Apply to Composite Components Mechanically Joined With Fasteners (MSFC Center Director's Discretionary Fund Final Report, Proj. 03-13}

    NASA Technical Reports Server (NTRS)

    Thomas, F. P.

    2006-01-01

    Aerospace structures utilize innovative, lightweight composite materials for exploration activities. These structural components, due to various reasons including size limitations, manufacturing facilities, contractual obligations, or particular design requirements, will have to be joined. The common methodologies for joining composite components are the adhesively bonded and mechanically fastened joints and, in certain instances, both methods are simultaneously incorporated into the design. Guidelines and recommendations exist for engineers to develop design criteria and analyze and test composites. However, there are no guidelines or recommendations based on analysis or test data to specify a torque or torque range to apply to metallic mechanical fasteners used to join composite components. Utilizing the torque tension machine at NASA s Marshall Space Flight Center, an initial series of tests were conducted to determine the maximum torque that could be applied to a composite specimen. Acoustic emissions were used to nondestructively assess the specimens during the tests and thermographic imaging after the tests.

  13. Torque-wrench extension

    NASA Technical Reports Server (NTRS)

    Peterson, D. H.

    1981-01-01

    Torque-wrench extension makes it easy to install and remove fasteners that are beyond reach of typical wrenches or are located in narrow spaces that prevent full travel of wrench handle. At same time, tool reads applied torque accurately. Wrench drive system, for torques up to 125 inch-pounds, uses 2 standard drive-socket extensions in aluminum frame. Extensions are connected to bevel gear that turns another bevel gear. Gears produce 1:1 turn ratio through 90 degree translation of axis of rotation. Output bevel has short extension that is used to attach 1/4-inch drive socket.

  14. Dynamic Torque Calibration Unit

    NASA Technical Reports Server (NTRS)

    Agronin, Michael L.; Marchetto, Carl A.

    1989-01-01

    Proposed dynamic torque calibration unit (DTCU) measures torque in rotary actuator components such as motors, bearings, gear trains, and flex couplings. Unique because designed specifically for testing components under low rates. Measures torque in device under test during controlled steady rotation or oscillation. Rotor oriented vertically, supported by upper angular-contact bearing and lower radial-contact bearing that floats axially to prevent thermal expansion from loading bearings. High-load capacity air bearing available to replace ball bearings when higher load capacity or reduction in rate noise required.

  15. Muscle synergy control model-tuned EMG driven torque estimation system with a musculo-skeletal model.

    PubMed

    Min, Kyuengbo; Shin, Duk; Lee, Jongho; Kakei, Shinji

    2013-01-01

    Muscle activity is the final signal for motion control from the brain. Based on this biological characteristic, Electromyogram (EMG) signals have been applied to various systems that interface human with external environments such as external devices. In order to use EMG signals as input control signal for this kind of system, the current EMG driven torque estimation models generally employ the mathematical model that estimates the nonlinear transformation function between the input signal and the output torque. However, these models need to estimate too many parameters and this process cause its estimation versatility in various conditions to be poor. Moreover, as these models are designed to estimate the joint torque, the input EMG signals are tuned out of consideration for the physiological synergetic contributions of multiple muscles for motion control. To overcome these problems of the current models, we proposed a new tuning model based on the synergy control mechanism between multiple muscles in the cortico-spinal tract. With this synergetic tuning model, the estimated contribution of multiple muscles for the motion control is applied to tune the EMG signals. Thus, this cortico-spinal control mechanism-based process improves the precision of torque estimation. This system is basically a forward dynamics model that transforms EMG signals into the joint torque. It should be emphasized that this forward dynamics model uses a musculo-skeletal model as a constraint. The musculo-skeletal model is designed with precise musculo-skeletal data, such as origins and insertions of individual muscles or maximum muscle force. Compared with the mathematical model, the proposed model can be a versatile model for the torque estimation in the various conditions and estimates the torque with improved accuracy. In this paper, we also show some preliminary experimental results for the discussion about the proposed model.

  16. Properties of vacuum brazed Si3N4/steel joint using active brazing filler metal

    NASA Astrophysics Data System (ADS)

    Bao, Fanghan; Ren, Jialie; Zhou, Yunhong; Yan, Ping

    The influence of active element Ti in Ag-Cu-Ti filler metal on wettability and joint strength is studied. Filler metal with 3 percent Ti achieves good results in direct brazing of silicon nitride to steel. For improving joint strength different interlayers are synthetically investigated. Experiments showed that an interlayer of low yield strength material can reduce the residual stress in the joint and increase joint strength more effectively than that of an interlayer of low coefficient of expansion material. Active element Ti in the brazing alloy diffused into Si3N4, and chemical reactions occurred in ceramic-metal interface producing certain chemical compounds consist of N and Ti.

  17. Potentiation increases peak twitch torque by enhancing rates of torque development and relaxation.

    PubMed

    Froyd, Christian; Beltrami, Fernando Gabe; Jensen, Jørgen; Noakes, Timothy David

    2013-01-01

    The aim of this study was to measure the extent to which potentiation changes in response to an isometric maximal voluntary contraction. Eleven physically active subjects participated in two separate studies. Single stimulus of electrical stimulation of the femoral nerve was used to measure torque at rest in unpotentiated quadriceps muscles (study 1 and 2), and potentiated quadriceps muscles torque in a 10 min period after a 5 s isometric maximal voluntary contraction of the quadriceps muscles (study 1). Additionally, potentiated quadriceps muscles torque was measured every min after a further 10 maximal voluntary contractions repeated every min (study 2). Electrical stimulation repeated several times without previous maximal voluntary contraction showed similar peak twitch torque. Peak twitch torque 4 s after a 5 s maximal voluntary contraction increased by 45±13% (study 1) and by 56±10% (study 2), the rate of torque development by 53±13% and 82±29%, and the rate of relaxation by 50±17% and 59±22%, respectively, but potentiation was lost already two min after a 5 s maximal voluntary contraction. There was a tendency for peak twitch torque to increase for the first five repeated maximal voluntary contractions, suggesting increased potentiation with additional maximal voluntary contractions. Correlations for peak twitch torque vs the rate of torque development and for the rate of relaxation were r(2)= 0.94 and r(2)=0.97. The correlation between peak twitch torque, the rate of torque development and the rate of relaxation suggests that potentiation is due to instantaneous changes in skeletal muscle contractility and relaxation.

  18. Acceleration control system for semi-active in-car crib with joint application of regular and inverted pendulum mechanisms

    NASA Astrophysics Data System (ADS)

    Kawashima, T.

    2016-09-01

    To reduce the risk of injury to an infant in an in-car crib (or in a child safety bed) collision shock during a car crash, it is necessary to maintain a constant force acting on the crib below a certain allowable value. To realize this objective, we propose a semi-active in-car crib system with the joint application of regular and inverted pendulum mechanisms. The arms of the proposed crib system support the crib like a pendulum while the pendulum system itself is supported like an inverted pendulum by the arms. In addition, the friction torque of each arm is controlled using a brake mechanism that enables the proposed in-car crib to decrease the acceleration of the crib gradually and maintain it around the target value. This system not only reduces the impulsive force but also transfers the force to the infant's back using a spin control system, i.e., the impulse force acts is made to act perpendicularly on the crib. The spin control system was developed in our previous work. This work focuses on the acceleration control system. A semi-active control law with acceleration feedback is introduced, and the effectiveness of the system is demonstrated using numerical simulation and model experiment.

  19. The effects of fatigue of the plantar flexors on peak torque and voluntary activation in untrained and resistance-trained men.

    PubMed

    Hartman, Michael J; Ryan, Eric D; Cramer, Joel T; Bemben, Michael G

    2011-02-01

    The purpose of this study was to compare the effects of fatigue of the plantar flexors on peak torque and voluntary activation in untrained (UT) and resistance-trained (RT) men. Six men with no previous resistance training experience and 8 men with similar histories of chronic resistance training (9.8 ± 5.9 years, 3.8 ± 0.7 days/week) volunteered for this study. Subjects performed isometric maximal voluntary contractions (MVCs) before and immediately after unilateral dynamic isotonic contractions performed at 40% of MVC until volitional exhaustion. Voluntary activation of the plantar flexors was assessed using the interpolated twitch method (ITT) and central activation ratio (CAR). Surface electromyographic (EMG) amplitude of the soleus and medial gastrocnemius (MG) was measured during the MVC. There were significant reductions in MVC torque in both UT and RT groups after the fatiguing exercise (-10.7 ± 6.8%, p < 0.02; -9.1 ± 8.7%, p < 0.02, respectively), with no difference in the number of repetitions performed between groups. The UT and RT men experienced a significant decrease in ITT after the fatiguing exercise bout (-14.2 ± 11.8%, p = 0.03; -7.8 ± 9.3%, p = 0.045, respectively). The UT group experienced a significant decrease in CAR (99.5 ± 0.8% to 91.4 ± 6.4%, p = 0.025) with no change (p > 0.05) in the RT group. There was also a fatigue-induced decrease in normalized EMG amplitude for the soleus and MG muscles in both groups (p < 0.05). However, no differences were determined between groups for ITT, CAR, or EMG. Despite similar reductions in MVC torque postexercise, the UT men had a significant decrease in CAR and experienced nearly twice the decline in ITT than the RT men. These results indicate that the neural adaptations associated with chronic resistance training may lead to less susceptibility to central fatigue as measured by ITT and CAR.

  20. Fabricated torque shaft

    SciTech Connect

    Mashey, Thomas Charles

    2002-01-01

    A fabricated torque shaft is provided that features a bolt-together design to allow vane schedule revisions with minimal hardware cost. The bolt-together design further facilitates on-site vane schedule revisions with parts that are comparatively small. The fabricated torque shaft also accommodates stage schedules that are different one from another in non-linear inter-relationships as well as non-linear schedules for a particular stage of vanes.

  1. 15 CFR 296.9 - Activities not permitted for joint ventures.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE NIST EXTRAMURAL PROGRAMS TECHNOLOGY INNOVATION PROGRAM General § 296.9 Activities not permitted for joint ventures. The following activities...

  2. Torque Control of a Rehabilitation Teaching Robot Using Magneto-Rheological Fluid Clutches

    NASA Astrophysics Data System (ADS)

    Hakogi, Hokuto; Ohaba, Motoyoshi; Kuramochi, Naimu; Yano, Hidenori

    A new robot that makes use of MR-fluid clutches for simulating torque is proposed to provide an appropriate device for training physical therapy students in knee-joint rehabilitation. The feeling of torque provided by the robot is expected to correspond to the torque performance obtained by physical therapy experts in a clinical setting. The torque required for knee-joint rehabilitation, which is a function of the rotational angle and the rotational angular velocity of a knee movement, is modeled using a mechanical system composed of typical spring-mass-damper elements. The robot consists of two MR-fluid clutches, two induction motors, and a feedback control system. In the torque experiments, output torque is controlled using the spring and damper coefficients separately. The values of these coefficients are determined experimentally. The experimental results show that the robot would be suitable for training physical therapy students to experience similar torque feelings as needed in a clinical situation.

  3. Joint Base Contracting: A Comparative Analysis of Joint Base Contracting Activities between Services

    DTIC Science & Technology

    2011-12-01

    AETC. Joint Base San Antonio also reached FOC October 1, 2010 ( Elliot , 2010). C. PROBLEM STATEMENT AND GAP IN LITERATURE No extensively researched...Publications. Eisenhardt, K. M. (1989). Building theories from case study research. Academy of Management Review, 14(4), 532–550. Elliot , S. (2010...Management Executive, 19(1), 46– 60. Sales, M.S. & Mirvis, P.H. (1984). When cultures collide: Issues of acquisitions. In J. R. Kimberly & E. R. Quinn

  4. An experimental comparison of the relative benefits of work and torque assistance in ankle exoskeletons.

    PubMed

    Jackson, Rachel W; Collins, Steven H

    2015-09-01

    Techniques proposed for assisting locomotion with exoskeletons have often included a combination of active work input and passive torque support, but the physiological effects of different assistance techniques remain unclear. We performed an experiment to study the independent effects of net exoskeleton work and average exoskeleton torque on human locomotion. Subjects wore a unilateral ankle exoskeleton and walked on a treadmill at 1.25 m·s(-1) while net exoskeleton work rate was systematically varied from -0.054 to 0.25 J·kg(-1)·s(-1), with constant (0.12 N·m·kg(-1)) average exoskeleton torque, and while average exoskeleton torque was systematically varied from approximately zero to 0.18 N·m·kg(-1), with approximately zero net exoskeleton work. We measured metabolic rate, center-of-mass mechanics, joint mechanics, and muscle activity. Both techniques reduced effort-related measures at the assisted ankle, but this form of work input reduced metabolic cost (-17% with maximum net work input) while this form of torque support increased metabolic cost (+13% with maximum average torque). Disparate effects on metabolic rate seem to be due to cascading effects on whole body coordination, particularly related to assisted ankle muscle dynamics and the effects of trailing ankle behavior on leading leg mechanics during double support. It would be difficult to predict these results using simple walking models without muscles or musculoskeletal models that assume fixed kinematics or kinetics. Data from this experiment can be used to improve predictive models of human neuromuscular adaptation and guide the design of assistive devices.

  5. Displaceable Gear Torque Controlled Driver

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1997-01-01

    Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

  6. Orion - Super Koropon(Registered Trademark) Torque/Tension Report

    NASA Technical Reports Server (NTRS)

    Hemminger, Edgar G.; McLeod, Christopher; Peil, John

    2012-01-01

    The primary objective of this testing was to obtain torque tension data for the use of Super Koropon Primer Base which was proposed for use on the Orion project. This compound is a corrosion inhibitor/sealer used on threaded fasteners and inserts as specified per NASA/JSC PRC-4004, Sealing of Joints and Faying Surfaces. Some secondary objectives of this testing, were to identify the effect on torque coefficient of several variables. This document contains the outcome of the testing.

  7. The joint inhibitory effects of phenol, copper (II), oxytetracycline (OTC) and sulfide on Anammox activity.

    PubMed

    Yang, Guang-Feng; Jin, Ren-Cun

    2012-12-01

    A batch test was employed to analyze the joint toxicity of copper (II) and oxytetracycline (OTC), OTC and sulfide, phenol and sulfide (S(2-)), phenol and copper (II), and OTC, copper (II) and substrate on an Anammox mixed culture. The joint toxicity of OTC and copper (II) on the Anammox mixed culture was antagonistic, whereas the interaction between OTC and S(2-) and between phenol and S(2-) was generally synergistic. The joint toxicity of phenol and copper (II) was dependent on the level of phenol: the joint toxicity was antagonistic at a high phenol level of 300 mg L(-1), whereas the joint toxicity was synergistic at a low phenol level of 75 mg L(-1). The joint toxic effect of OTC, copper (II) and NO(2)(-)-N on the Anammox activity can be ranked in the following order: NO(2)(-)-N>copper (II)>OTC.

  8. Dynamic Structure of Joint-Action Stimulus-Response Activity

    PubMed Central

    Malone, MaryLauren; Castillo, Ramon D.; Kloos, Heidi; Holden, John G.; Richardson, Michael J.

    2014-01-01

    The mere presence of a co-actor can influence an individual’s response behavior. For instance, a social Simon effect has been observed when two individuals perform a Go/No-Go response to one of two stimuli in the presence of each other, but not when they perform the same task alone. Such effects are argued to provide evidence that individuals co-represent the task goals and the to-be-performed actions of a co-actor. Motivated by the complex-systems approach, the present study was designed to investigate an alternative hypothesis — that such joint-action effects are due to a dynamical (time-evolving) interpersonal coupling that operates to perturb the behavior of socially situated actors. To investigate this possibility, participants performed a standard Go/No-Go Simon task in joint and individual conditions. The dynamic structure of recorded reaction times was examined using fractal statistics and instantaneous cross-correlation. Consistent with our hypothesis that participants responding in a shared space would become behaviorally coupled, the analyses revealed that reaction times in the joint condition displayed decreased fractal structure (indicative of interpersonal perturbation processes modulating ongoing participant behavior) compared to the individual condition, and were more correlated across a range of time-scales compared to the reaction times of pseudo-pair controls. Collectively, the findings imply that dynamic processes might underlie social stimulus-response compatibility effects and shape joint cognitive processes in general. PMID:24558467

  9. Obesity effect on male active joint range of motion.

    PubMed

    Park, Woojin; Ramachandran, Jaiganesh; Weisman, Paul; Jung, Eui S

    2010-01-01

    Despite the prevalence of obesity, how obesity affects human physical capabilities is not well documented. As an effort toward addressing this, the current study investigated the obesity effect on joint range of motion (RoM) based on data collected from 20 obese and 20 non-obese males. In total, 30 inter-segmental motions occurring at the shoulder, elbow, knee and ankle joints and lumbar and cervical spine areas were examined. The obesity effect was found to be non-uniform across the joint motions. Obesity significantly reduced RoM for nine of the 30 motions: shoulder extensions and adductions, lumbar spine extension and lateral flexions and knee flexions. The largest significant RoM reduction was 38.9% for the left shoulder adduction. The smallest was 11.1% for the right knee flexion. The obesity-associated RoM reductions appear to be mainly due to the mechanical interposition and obstruction of inter-segmental motions caused by excess fat in the obese body. STATEMENT OF RELEVANCE: Currently, obesity is prevalent worldwide and its prevalence is expected to increase continually in the near future. This study empirically characterised the obesity effects on joint RoM to provide better understanding of the physical capabilities of the obese. The study findings will facilitate designing man-artefact systems that accommodate obese individuals.

  10. Effect of antagonist muscle fatigue on knee extension torque.

    PubMed

    Beltman, J G M; Sargeant, A J; Ball, D; Maganaris, C N; de Haan, A

    2003-09-01

    The effect of hamstring fatigue on knee extension torque was examined at different knee angles for seven male subjects. Before and after a dynamic flexion fatigue protocol (180 degrees s(-1), until dynamic torque had declined by 50%), maximal voluntary contraction extension torque was measured at four knee flexion angles (90 degrees, 70 degrees, 50 degrees and 30 degrees ). Maximal torque generating capacity and voluntary activation of the quadriceps muscle were determined using electrical stimulation. Average rectified EMG of the biceps femoris was determined. Mean dynamic flexion torque declined by 48+/-11%. Extensor maximal voluntary contraction torque, maximal torque generating capacity, voluntary activation and average rectified EMG at the four knee angles were unaffected by the hamstring fatigue protocol. Only at 50 degrees knee angle was voluntary activation significantly lower (15.7%) after fatigue ( P<0.05). In addition, average rectified EMG before fatigue was not significantly influenced by knee angle. It was concluded that a fatigued hamstring muscle did not increase the maximal voluntary contraction extension torque and knee angle did not change coactivation. Three possible mechanisms may explain the results: a potential difference in recruited fibre populations in antagonist activity compared with the fibres which were fatigued in the protocol, a smaller loss in isometric torque generating capacity of the hamstring muscle than was expected from the dynamic measurements and/or a reduction in voluntary activation.

  11. Torque-stiffness-controlled dynamic walking with central pattern generators.

    PubMed

    Huang, Yan; Vanderborght, Bram; Van Ham, Ronald; Wang, Qining

    2014-12-01

    Walking behavior is modulated by controlling joint torques in most existing passivity-based bipeds. Controlled Passive Walking with adaptable stiffness exhibits controllable natural motions and energy efficient gaits. In this paper, we propose torque-stiffness-controlled dynamic bipedal walking, which extends the concept of Controlled Passive Walking by introducing structured control parameters and a bio-inspired control method with central pattern generators. The proposed walking paradigm is beneficial in clarifying the respective effects of the external actuation and the internal natural dynamics. We present a seven-link biped model to validate the presented walking. Effects of joint torque and joint stiffness on gait selection, walking performance and walking pattern transitions are studied in simulations. The work in this paper develops a new solution of motion control of bipedal robots with adaptable stiffness and provides insights of efficient and sophisticated walking gaits of humans.

  12. Torque multiplier subsea tool

    SciTech Connect

    Leicht, F. M.; Baugh, B. F.; Palany, H. C.

    1985-10-22

    A torque multiplier subsea tool for setting a seal between a casing hanger and a subsea wellhead includes a mandrel having a sun gear with axial elongate teeth. An outer barrel is disposed around the mandrel forming an annulus therebetween. A planetary gear assembly is disposed in the annulus between the barrel and the sun gear to transmit to the barrel a torque which is higher in magnitude than that applied to the mandrel. A connector body disposed around the mandrel, below the planetary gear assembly, includes radially movable dogs for engaging the casing hanger. The barrel engages the sealing assembly and transmits the increased torque thereto to advance the sealing assembly downwards and to set the seal. The mandrel advances downwards with the sealing assembly and releases the dogs from the casing hanger. An emergency release mechanism is provided to advance the mandrel downwards to release the dogs in the event such downward movement is prevented during normal seal setting operation.

  13. Negative Optical Torque

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Ng, Jack; Ding, Kun; Fung, Kin Hung; Lin, Zhifang; Chan, C. T.

    2014-09-01

    Light carries angular momentum, and as such it can exert torques on material objects. Applications of these opto-mechanical effects were limited initially due to their smallness in magnitude, but later becomes powerful and versatile after the invention of laser. Novel and practical approaches for harvesting light for particle rotation have since been demonstrated, where the structure is always subjected to a positive optical torque along a certain axis if the incident angular momentum has a positive projection on the same axis. We report here an interesting phenomenon of ``negative optical torque'', meaning that incoming photons carrying angular momentum rotate an object in the opposite sense. Surprisingly this can be realized quite straightforwardly in simple planar structures. Field retardation is a necessary condition and discrete rotational symmetry of material object plays an important role. The optimal conditions are explored and explained.

  14. Negative optical torque.

    PubMed

    Chen, Jun; Ng, Jack; Ding, Kun; Fung, Kin Hung; Lin, Zhifang; Chan, C T

    2014-09-17

    Light carries angular momentum, and as such it can exert torques on material objects. Applications of these opto-mechanical effects were limited initially due to their smallness in magnitude, but later becomes powerful and versatile after the invention of laser. Novel and practical approaches for harvesting light for particle rotation have since been demonstrated, where the structure is always subjected to a positive optical torque along a certain axis if the incident angular momentum has a positive projection on the same axis. We report here an interesting phenomenon of "negative optical torque", meaning that incoming photons carrying angular momentum rotate an object in the opposite sense. Surprisingly this can be realized quite straightforwardly in simple planar structures. Field retardation is a necessary condition and discrete rotational symmetry of material object plays an important role. The optimal conditions are explored and explained.

  15. Ironless armature torque motor

    NASA Technical Reports Server (NTRS)

    Fisher, R. L.

    1972-01-01

    Four iron-less armature torque motors, four Hall device position sensor assemblies, and two test fixtures were fabricated. The design approach utilized samarium cobalt permanent magnets, a large airgap, and a three-phase winding in a stationary ironless armature. Hall devices were employed to sense rotor position. An ironless armature torque motor having an outer diameter of 4.25 inches was developed to produce a torque constant of 65 ounce-inches per ampere with a resistance of 20.5 ohms. The total weight, including structural elements, was 1.58 pounds. Test results indicated that all specifications were met except for generated voltage waveform. It is recommended that investigations be made concerning the generated voltage waveform to determine if it may be improved.

  16. Method for analyzing articulated torques of heavy-duty six-legged robot

    NASA Astrophysics Data System (ADS)

    Zhuang, Hongchao; Gao, Haibo; Ding, Liang; Liu, Zhen; Deng, Zongquan

    2013-07-01

    The accuracy of an articulated torque analysis influences the comprehensive performances of heavy-duty multi-legged robots. Currently, the extremal estimation method and some complex methods are employed to calculate the articulated torques, which results in a large safety margin or a large number of calculations. To quickly obtain accurate articulated torques, an analysis method for the articulated torque is presented for an electrically driven heavy-duty six-legged robot. First, the rearmost leg that experiences the maximum normal contact force is confirmed when the robot transits a slope. Based on the ant-type and crab-type tripod gaits, the formulas of classical mechanics and MATLAB software are employed to theoretically analyze the relevant static torques of the joints. With the changes in the joint angles for the abductor joint, hip joint, and knee joint, variable tendency charts and extreme curves are obtained for the static articulated torques. Meanwhile, the maximum static articulated torques and the corresponding poses of the robot are also obtained. According to the poses of the robot under the maximum static articulated torques, ADAMS software is used to carry out a static simulation analysis. Based on the relevant simulation curves of the articulated torques, the maximum static articulated torques are acquired. A comparative analysis of the maximum static articulated torques shows that the theoretical calculation values are higher than the static simulation values, and the maximum error value is approximately 10%. The proposed method lays a foundation for quickly determining accurate articulated torques to develop heavy-duty six-legged robots.

  17. Torque Control of Underactuated Tendon-driven Robotic Fingers

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Ihrke, Chris A. (Inventor); Reiland, Matthew J. (Inventor); Wampler, Charles W. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Bridgwater, Lyndon (Inventor)

    2013-01-01

    A robotic system includes a robot having a total number of degrees of freedom (DOF) equal to at least n, an underactuated tendon-driven finger driven by n tendons and n DOF, the finger having at least two joints, being characterized by an asymmetrical joint radius in one embodiment. A controller is in communication with the robot, and controls actuation of the tendon-driven finger using force control. Operating the finger with force control on the tendons, rather than position control, eliminates the unconstrained slack-space that would have otherwise existed. The controller may utilize the asymmetrical joint radii to independently command joint torques. A method of controlling the finger includes commanding either independent or parameterized joint torques to the controller to actuate the fingers via force control on the tendons.

  18. Textured bearing surface in artificial joints to reduce macrophage activation

    NASA Astrophysics Data System (ADS)

    Nakanishi, Yoshitaka; Nishi, Naoki; Chikaura, Hiroto; Nakashima, Yuta; Miura, Hiromasa; Higaki, Hidehiko; Mizuta, Hiroshi; Iwamoto, Yukihide; Fujiwara, Yukio; Komohara, Yoshihiro; Takeya, Motohiro

    2015-12-01

    Micro slurry-jet erosion has been proposed as a precision machining technique for the bearing surfaces of artificial joints in order to reduce the total amount of polyethylene wear and to enlarge the size of the wear debris. The micro slurry-jet erosion method is a wet blasting technique which uses alumina particles as the abrasive medium along with compressed air and water to create an ideal surface. Pin-on-disc wear tests with multidirectional sliding motion on the textured surface of a \\text{Co}-\\text{Cr}-\\text{Mo} alloy counterface for polyethylene resulted in both a reduction of wear as well as enlargement of the polyethylene debris size. In this study, primary human peripheral blood mononuclear phagocytes were incubated with the debris, and it was elucidated that the wear debris generated on the textured surface regulated secretion of the proinflammatory cytokines IL-6 and TNF-α, indicating a reduction in the induced tissue reaction and joint loosening.

  19. The effect of an active vibration stimulus according to different shoulder joint angles on functional reach and stability of the shoulder joint

    PubMed Central

    Kim, Eun-Kyung; Kim, Seong-Gil

    2016-01-01

    [Purpose] The purpose of this study was to analyze the effect of an active vibration stimulus exercise according to shoulder joint angles on functional reach and stability of the shoulder joint. [Subjects and Methods] Thirty healthy male students participated in this study. Upper limb length of each subject was measured to obtain normalized measurement values. The exercise groups were as follows: group I (n=10, shoulder joint angle of 90°), group II (n=10, shoulder joint angle of 130°), and group III (n=10, shoulder joint angle of 180°). After warm-up, an active vibration stimulus was applied to the subjects with a Flexi-Bar. The Functional Reach Test and Y-balance test were conducted for measurement of shoulder stability. [Results] Analysis of covariance was conducted with values before the intervention as covariates to analyze the differences among the groups in the two tests. There were significant differences among the groups. According to Bonferroni post hoc comparison, group I showed greater improvement than group III in the Functional Reach Test, and group II showed greater improvement than group I and group III in the Y-balance test. [Conclusion] The effect of the exercise with different shoulder joint angles revealed that the shoulder joint has a certain effective joint angle for its functionality and stability. In addition, application of an active vibration stimulus with a Flexi-Bar can be a very effective tool for improvement of functionality and stability of the shoulder joint. PMID:27134352

  20. Shortening-induced torque depression in old men: implications for age-related power loss.

    PubMed

    Power, Geoffrey A; Makrakos, Demetri P; Stevens, Daniel E; Herzog, Walter; Rice, Charles L; Vandervoort, Anthony A

    2014-09-01

    Following active muscle shortening, the steady-state isometric torque at the final muscle length is lower than the steady-state torque obtained for a purely isometric contraction at that same final muscle length. This well-documented property of skeletal muscle is termed shortening-induced torque depression (TD). Despite many investigations into the mechanisms of weakness and power loss in old age, the influence of muscle shortening on the history dependence of isometric torque production remains to be elucidated. Thus, it is unclear whether older adults are disadvantaged for torque and power production following a dynamic shortening contraction. The purpose of this study was to evaluate shortening-induced TD in older adults, and to determine whether shortening-induced TD is related to power loss. Maximal voluntary isometric dorsiflexion contractions (MVC; 10s) in 8 young (25.5±3.7years) and 9 old (76.1±5.4years) men were performed on a HUMAC NORM dynamometer as a reference, and then again following an active shortening of 40° joint excursion (40°PF-0°PF) at angular velocities of 15°/s and 120°/s. Work and instantaneous power were derived during shortening. Shortening-induced TD was calculated and expressed as a percentage by determining the mean torque value over 1s during the isometric steady state of the MVC following shortening, divided by the mean torque value for the same 1s time period during the isometric reference MVC. To assess muscle activation, electromyography (root mean square; EMGRMS) of the tibialis anterior (TA) and soleus (SOL) was calculated at identical time points used in assessing shortening-induced TD, and voluntary activation (VA) was assessed using the interpolated twitch technique. Old were 18% weaker than young for MVC, and ~40% less powerful for 15°/s and 120°/s of shortening. Old produced 37% and 21% less work for 15°/s and 120°/s than young, respectively. Furthermore, old experienced 60% and 70% greater shortening-induced TD

  1. Local Interleukin-1-Driven Joint Pathology Is Dependent on Toll-Like Receptor 4 Activation

    PubMed Central

    Abdollahi-Roodsaz, Shahla; Joosten, Leo A.B.; Koenders, Marije I.; van den Brand, Ben T.; van de Loo, Fons A.J.; van den Berg, Wim B.

    2009-01-01

    Toll-like receptors (TLRs) may contribute to the pathogenesis of chronic inflammatory destructive diseases through the recognition of endogenous ligands produced on either inflammation or degeneration of the extracellular matrix. The presence of endogenous TLR agonists has been reported in rheumatoid joints. In the present study, we investigated the significance of TLR2 and TLR4 activation by locally- produced endogenous ligands in the severity of joint inflammation and destruction. Local joint pathology independent of systemic immune activation was induced by overexpression of interleukin (IL)-1 and TNF in naive joints using adenoviral gene transfer. Here, we report that at certain doses, IL-1-induced local joint inflammation, cartilage proteoglycan depletion, and bone erosion are dependent on TLR4 activation, whereas TLR2 activation is not significantly involved. In comparison, tumor necrosis factor α-driven joint pathology seemed to be less dependent on TLR2 and TLR4. The severity of IL-1-induced bone erosion and irreversible cartilage destruction was markedly reduced in TLR4−/− mice, even though the degree of inflammation was similar, suggesting uncoupled processes. Furthermore, the expression of cathepsin K, a marker for osteoclast activity, induced by IL-1β was dependent on TLR4. Overexpression of IL-1β in the joint as well as ex vivo IL-1 stimulation of patellae provoked the release of endogenous TLR4 agonists capable of inducing TLR4-mediated cytokine production. These data emphasize the potential relevance of TLR4 activation in rheumatoid arthritis, particularly with respect to IL-1-mediated joint pathology. PMID:19834062

  2. Torque, Cognitive Ability, and Schooling.

    ERIC Educational Resources Information Center

    Csapo, Marg

    1985-01-01

    West African Hausan Children (N=110) aged 5-6 were administered a torque test and relationshps between the torque task and visual spatial tasks were analyzed. Findings supported the assumption that educational experience related to circling accounts for decrease in torque, or that the educational experiences have potential influence on cortical…

  3. Floating-Pinion Torque Splitter

    NASA Technical Reports Server (NTRS)

    Melles, Harold W.

    1994-01-01

    Designed-in looseness at right locations helps to distribute torques more evenly. Gear-drive mechanism helps to apportion torques nearly equally along two parallel drive paths from input bevel gear to output bull gear. Mechanism of this type used as part of redundant drive train between engine and rotor of helicopter. Weighs less than comparably rated prior torque-splitting mechanisms.

  4. Torque-Splitting Gear Drive

    NASA Technical Reports Server (NTRS)

    Kish, J.

    1991-01-01

    Geared drive train transmits torque from input shaft in equal parts along two paths in parallel, then combines torques in single output shaft. Scheme reduces load on teeth of meshing gears while furnishing redundancy to protect against failures. Such splitting and recombination of torques common in design of turbine engines.

  5. Torque Splitting by a Concentric Face Gear Transmission

    NASA Technical Reports Server (NTRS)

    Filler, Robert R.; Heath, Gregory F.; Slaughter, Stephen C.; Lewicki, David G.

    2002-01-01

    Tests of a 167 Kilowatt (224 Horsepower) split torque face gearbox were performed by the Boeing Company in Mesa, Arizona, while working under a Defense Advanced Research Projects Agency (DARPA) Technology Reinvestment Program (TRP). This paper provides a summary of these cooperative tests, which were jointly funded by Boeing and DARPA. Design, manufacture and testing of the scaled-power TRP proof-of-concept (POC) split torque gearbox followed preliminary evaluations of the concept performed early in the program. The split torque tests were run using 200 N-m (1767 in-lbs) torque input to each side of the transmission. During tests, two input pinions were slow rolled while in mesh with the two face gears. Two idler gears were also used in the configuration to recombine torque near the output. Resistance was applied at the output face gear to create the required loading conditions in the gear teeth. A system of weights, pulleys and cables were used in the test rig to provide both the input and output loading. Strain gages applied in the tooth root fillets provided strain indication used to determine torque splitting conditions at the input pinions. The final two pinion-two idler tests indicated 52% to 48% average torque split capabilities for the two pinions. During the same tests, a 57% to 43% average distribution of the torque being recombined to the upper face gear from the lower face gear was measured between the two idlers. The POC split torque tests demonstrated that face gears can be applied effectively in split torque rotorcraft transmissions, yielding good potential for significant weight, cost and reliability improvements over existing equipment using spiral bevel gearing.

  6. Comparison of different passive knee extension torque-angle assessments.

    PubMed

    Freitas, Sandro R; Vaz, João R; Bruno, Paula M; Valamatos, Maria J; Mil-Homens, Pedro

    2013-11-01

    Previous studies have used isokinetic dynamometry to assess joint torques and angles during passive extension of the knee, often without reporting upon methodological errors and reliability outcomes. In addition, the reliability of the techniques used to measure passive knee extension torque-angle and the extent to which reliability may be affected by the position of the subjects is also unclear. Therefore, we conducted an analysis of the intra- and inter-session reliability of two methods of assessing passive knee extension: (A) a 2D kinematic analysis coupled to a custom-made device that enabled the direct measurement of resistance to stretch and (B) an isokinetic dynamometer used in two testing positions (with the non-tested thigh either flexed at 45° or in the neutral position). The intra-class correlation coefficients (ICCs) of torque, the slope of the torque-angle curve, and the parameters of the mathematical model that were fit to the torque-angle data for the above conditions were measured in sixteen healthy male subjects (age: 21.4 ± 2.1 yr; BMI: 22.6 ± 3.3 kg m(-2); tibial length: 37.4 ± 3.4 cm). The results found were: (1) methods A and B led to distinctly different torque-angle responses; (2) passive torque-angle relationship and stretch tolerance were influenced by the position of the non-tested thigh; and (3) ICCs obtained for torque were higher than for the slope and for the mathematical parameters that were fit to the torque-angle curve. In conclusion, the measurement method that is used and the positioning of subjects can influence the passive knee extension torque-angle outcome.

  7. Exploring the Neural Basis of Real-Life Joint Action: Measuring Brain Activation during Joint Table Setting with Functional Near-Infrared Spectroscopy

    PubMed Central

    Egetemeir, Johanna; Stenneken, Prisca; Koehler, Saskia; Fallgatter, Andreas J.; Herrmann, Martin J.

    2011-01-01

    Many every-day life situations require two or more individuals to execute actions together. Assessing brain activation during naturalistic tasks to uncover relevant processes underlying such real-life joint action situations has remained a methodological challenge. In the present study, we introduce a novel joint action paradigm that enables the assessment of brain activation during real-life joint action tasks using functional near-infrared spectroscopy (fNIRS). We monitored brain activation of participants who coordinated complex actions with a partner sitting opposite them. Participants performed table setting tasks, either alone (solo action) or in cooperation with a partner (joint action), or they observed the partner performing the task (action observation). Comparing joint action and solo action revealed stronger activation (higher [oxy-Hb]-concentration) during joint action in a number of areas. Among these were areas in the inferior parietal lobule (IPL) that additionally showed an overlap of activation during action observation and solo action. Areas with such a close link between action observation and action execution have been associated with action simulation processes. The magnitude of activation in these IPL areas also varied according to joint action type and its respective demand on action simulation. The results validate fNIRS as an imaging technique for exploring the functional correlates of interindividual action coordination in real-life settings and suggest that coordinating actions in real-life situations requires simulating the actions of the partner. PMID:21927603

  8. Abdominal muscle activity according to knee joint angle during sit-to-stand

    PubMed Central

    Eom, Juri; Rhee, Min-Hyung; Kim, Laurentius Jongsoon

    2016-01-01

    [Purpose] This study assessed the activity of the abdominal muscles according to the angle of the knee joints during sit-to-stand. [Subjects and Methods] Thirty healthy adult males participated in this study. Subjects initiated sit-to-stand at knee joint angles of 60°, 90°, or 120°. An electromyography system was used to measure the maximum voluntary isometric contraction of the rectus abdominis, external oblique, and internal oblique and transverse abdominis muscles. [Results] Percent contraction differed significantly among the three knee joint angles, most notably for the internal oblique and transverse abdominis muscles. [Conclusion] Wider knee joint angles more effectively activate the abdominal muscles, especially those in the deep abdomen, than do narrower angles. PMID:27390431

  9. Accuracy of dental torque wrenches.

    PubMed

    Wood, James S; Marlow, Nicole M; Cayouette, Monica J

    2015-01-01

    The aim of this in vitro study was to compare the actual torque of 2 manual wrench systems to their stated (target) torque. New spring- (Nobel Biocare USA, LLC) and friction-style (Zimmer Dental, Inc.) manual dental torque wrenches, as well as spring torque wrenches that had undergone sterilization and clinical use, were tested. A calibrated torque gauge was used to compare actual torque to target torque values of 15 and 35 N/cm. Data were statistically analyzed via mixed-effects regression model with Bonferroni correction. At a target torque of 15 N/cm, the mean torque of new spring wrenches (13.97 N/cm; SE, 0.07 N/cm) was significantly different from that of used spring wrenches (14.94 N/cm; SE, 0.06 N/cm; P < 0.0001). However, the mean torques of new spring and new friction wrenches (14.10 N/cm; SE, 0.07 N/cm; P = 0.21) were not significantly different. For torque measurements calibrated at 35 N/cm, the mean torque of new spring wrenches (35.29 N/cm; SE, 0.10 N/cm) was significantly different (P < 0.0001) from the means of new friction wrenches (36.20 N/cm; SE, 0.08 N/cm) and used spring wrenches (36.45 N/cm; SE, 0.08 N/cm). Discrepancies in torque could impact the clinical success of screw-retained dental implants. It is recommended that torque wrenches be checked regularly to ensure that they are performing to target values.

  10. Mechanics of Re-Torquing in Bolted Flange Connections

    NASA Technical Reports Server (NTRS)

    Gordon, Ali P.; Drilling Brian; Weichman, Kyle; Kammerer, Catherine; Baldwin, Frank

    2010-01-01

    It has been widely accepted that the phenomenon of time-dependent loosening of flange connections is a strong consequence of the viscous nature of the compression seal material. Characterizing the coupled interaction between gasket creep and elastic bolt stiffness has been useful in predicting conditions that facilitate leakage. Prior advances on this sub-class of bolted joints has lead to the development of (1) constitutive models for elastomerics, (2) initial tightening strategies, (3) etc. The effect of re-torque, which is a major consideration for typical bolted flange seals used on the Space Shuttle fleet, has not been fully characterized, however. The current study presents a systematic approach to characterizing bolted joint behavior as the consequence of sequentially applied torques. Based on exprimenta1 and numerical results, the optimal re-torquing parameters have been identified that allow for the negligible load loss after pre-load application

  11. Creep Deformation and Rupture Behavior of Single- and Dual-Pass 316LN Stainless-Steel-Activated TIG Weld Joints

    NASA Astrophysics Data System (ADS)

    Vijayanand, V. D.; Vasudevan, M.; Ganesan, V.; Parameswaran, P.; Laha, K.; Bhaduri, A. K.

    2016-06-01

    Creep deformation and rupture behavior of single-pass and dual-pass 316LN stainless steel (SS) weld joints fabricated by an autogenous activated tungsten inert gas welding process have been assessed by performing metallography, hardness, and conventional and impression creep tests. The fusion zone of the single-pass joint consisted of columnar zones adjacent to base metals with a central equiaxed zone, which have been modified extensively by the thermal cycle of the second pass in the dual-pass joint. The equiaxed zone in the single-pass joint, as well as in the second pass of the dual-pass joint, displayed the lowest hardness in the joints. In the dual-pass joint, the equiaxed zone of the first pass had hardness comparable to the columnar zone. The hardness variations in the joints influenced the creep deformation. The equiaxed and columnar zone in the first pass of the dual-pass joint was more creep resistant than that of the second pass. Both joints possessed lower creep rupture life than the base metal. However, the creep rupture life of the dual-pass joint was about twofolds more than that of the single-pass joint. Creep failure in the single-pass joint occurred in the central equiaxed fusion zone, whereas creep cavitation that originated in the second pass was blocked at the weld pass interface. The additional interface and strength variation between two passes in the dual-pass joint provides more restraint to creep deformation and crack propagation in the fusion zone, resulting in an increase in the creep rupture life of the dual-pass joint over the single-pass joint. Furthermore, the differences in content, morphology, and distribution of delta ferrite in the fusion zone of the joints favors more creep cavitation resistance in the dual-pass joint over the single-pass joint with the enhancement of creep rupture life.

  12. Modelling grain alignment by radiative torques and hydrogen formation torques in reflection nebula

    NASA Astrophysics Data System (ADS)

    Hoang, Thiem; Lazarian, A.; Andersson, B.-G.

    2015-04-01

    Reflection nebulae - dense cores - illuminated by surrounding stars offer a unique opportunity to directly test our quantitative model of grain alignment based on radiative torques (RATs) and to explore new effects arising from additional torques. In this paper, we first perform detailed modelling of grain alignment by RATs for the IC 63 reflection nebula illuminated both by a nearby γ Cas star and the diffuse interstellar radiation field. We calculate linear polarization pλ of background stars by radiatively aligned grains and explore the variation of fractional polarization (pλ/AV) with visual extinction AV across the cloud. Our results show that the variation of pV/AV versus AV from the dayside of IC 63 to its centre can be represented by a power law (p_V/A_V∝ A_V^{η }) with different slopes depending on AV. We find a shallow slope η ˜ -0.1 for AV < 3 and a very steep slope η ˜ -2 for AV > 4. We then consider the effects of additional torques due to H2 formation and model grain alignment by joint action of RATs and H2 torques. We find that pV/AV tends to increase with an increasing magnitude of H2 torques. In particular, the theoretical predictions obtained for pV/AV and peak wavelength λmax in this case show an improved agreement with the observational data. Our results reinforce the predictive power of the RAT alignment mechanism in a broad range of environmental conditions and show the effect of pinwheel torques in environments with efficient H2 formation. Physical parameters involved in H2 formation may be constrained using detailed modelling of grain alignment combined with observational data. In addition, we discuss implications of our modelling for interpreting latest observational data by Planck and other ground-based instruments.

  13. Physical activity in the elderly who underwent joint replacement surgery in the course of rheumatic diseases

    PubMed Central

    Komorowski, Arkadiusz; Przepióra, Wiktor; Księżopolska-Orłowska, Krystyna

    2016-01-01

    According to the forecasts of the Central Statistical Office of Poland, in 2030 people at the age of 65 and older will account for 23.8%, i.e. their number will amount to approx. 8.5 m people. Geriatric rheumatic patients more often decide to undergo surgical joint replacement. According to the National Health Fund, the number of joint replacement services provided in 2014 increased by 93%, as compared to 2005. Improving the physical performance of this constantly expanding group of patients requires taking into account many factors to raise their functional status, reduce the risk of falling, teach rules of proper functioning with an artificial joint and encourage unassisted physical activity. Restoring fitness and independence is a difficult but necessary task due to an increasing number of seniors with replaced joint. PMID:27504021

  14. Physical activity in the elderly who underwent joint replacement surgery in the course of rheumatic diseases.

    PubMed

    Prusinowska, Agnieszka; Komorowski, Arkadiusz; Przepióra, Wiktor; Księżopolska-Orłowska, Krystyna

    2016-01-01

    According to the forecasts of the Central Statistical Office of Poland, in 2030 people at the age of 65 and older will account for 23.8%, i.e. their number will amount to approx. 8.5 m people. Geriatric rheumatic patients more often decide to undergo surgical joint replacement. According to the National Health Fund, the number of joint replacement services provided in 2014 increased by 93%, as compared to 2005. Improving the physical performance of this constantly expanding group of patients requires taking into account many factors to raise their functional status, reduce the risk of falling, teach rules of proper functioning with an artificial joint and encourage unassisted physical activity. Restoring fitness and independence is a difficult but necessary task due to an increasing number of seniors with replaced joint.

  15. Adaptive tracking of weld joints using active contour model in arc-welding processes

    NASA Astrophysics Data System (ADS)

    Kim, Jaeseon; Koh, Kyoungchul; Cho, Hyungsuck

    2001-02-01

    12 This paper presents a vision processing scheme to automatic weld joint tracking in robotic arc welding process. Particular attention is concentrated on its robustness against various optical disturbances, such as arc glares and weld spatters radiating from the melted weld pool. Underlying the developed vision processing is a kind of model-based pattern searching, which is necessarily accompanied by two separate stages of modeling and tracking. In the modeling stage, a syntactic approach is adopted to identify unknown weld joint structure. The joint profile identified in the modeling stage is used as a starting point for successive tracking of variations in the geometry of weld joint during welding, which is automatically achieved by an active contour model technology following feature- based template matching. The performance of the developed scheme is investigated through a series of practical welding experiments.

  16. A New Twist on Torque Labs

    ERIC Educational Resources Information Center

    Lane, W. Brian

    2014-01-01

    The traditional introductory-level meterstick-balancing lab assumes that students already know what torque is and that they readily identify it as a physical quantity of interest. We propose a modified version of this activity in which students qualitatively and quantitatively measure the amount of force required to keep the meterstick level. The…

  17. Recreational Sports Activities After Calcaneal Fractures and Subsequent Subtalar Joint Arthrodesis.

    PubMed

    Romeo, Giovanni; Martinelli, Nicolò; Bonifacini, Carlo; Bianchi, Alberto; Sartorelli, Elena; Malerba, Francesco

    2015-01-01

    Subtalar joint arthrodesis is a common treatment for the management of hindfoot pathologic entities. Despite pain reduction, hindfoot stiffness is a common concern of active patients, who wish to continue or start exercising for fitness. The purpose of the present retrospective observational clinical study was to assess the rate and type of recreational sports activities in patients before and after subtalar joint arthrodesis and to correlate the clinical outcome and the level of sports activities. In 33 patients (22 males, 11 females) treated with subtalar joint arthrodesis, the pre- and postoperative participation in sports and recreational activities was evaluated. The American Orthopaedic Foot and Ankle Society hindfoot scale score, 36-item Short Form Health Survey, and a visual analog scale for pain were used as clinical outcome measures. The weekly session number, session time, and interval to activity recovery after surgery were registered. Patients with a subtalar joint arthrodesis returned to a satisfactory level of activity postoperatively. The sports participation almost reached levels similar to those preoperatively but with a shift from high- to low-impact activities.

  18. Decision making and experience level influence frontal plane knee joint biomechanics during a cutting maneuver.

    PubMed

    Kipp, Kristof; Brown, Tyler N; McLean, Scott G; Palmieri-Smith, Riann M

    2013-12-01

    The purpose of this study was to examine the combined impact of experience and decision making on frontal plane knee joint biomechanics during a cutting maneuver. Kinematic and kinetic data were collected from 12 recreationally active and 18 NCAA Division I female athletes during execution of anticipated and unanticipated single-leg land-and-cut maneuvers. Knee joint abduction angles and external knee joint abduction torques were calculated and discrete peak stance-phase variables were extracted. Angle and torque time-series data were also submitted to separate functional data analyses. Variables derived from the functional data analyses indicated that decision making influenced knee abduction angle and torque time series in the recreational group only. Specifically, these variables pointed to greater knee abduction at the end of stance as well as a greater, albeit delayed peak in knee abduction torque at the beginning of landing in the recreational athletes during the unanticipated condition. In addition, the recreational athletes displayed greater discrete peak knee abduction angles than the Division I athletes regardless of condition. Discrete peak knee abduction torque did not differ between groups or conditions.

  19. Adaptive control for backward quadrupedal walking VI. metatarsophalangeal joint dynamics and motor patterns of digit muscles.

    PubMed

    Trank, T V; Smith, J L

    1996-02-01

    1. We compared the dynamics of the metatarsophalangeal (MTP) joint of the cat's hind paw and the motor patterns of two short and four long muscles of the digits for two walking forms, forward (FWD) and backward (BWD). Kinematic (angular displacements) data digitized from high-speed ciné film and electromyographic (EMG) data were synchronized and assessed for bouts of treadmill walking. Kinetic data (joint forces) were calculated from kinematic and anthropometric data with the use of inverse-dynamic calculations in which the MTP joint net torque was divided into gravitational, motion-dependent, ground contact (absent for swing), and muscle torque components. Swing-phase kinetics were calculated from treadmill steps and stance-phase kinetics from overground steps in which one hind paw contacted a miniature force platform embedded in the walkway. 2. The plantar angle at the intersection of the metatarsal and phalangeal segmental lines was used to measure MTP angular displacements. During swing for both walking forms, the MTP joint flexed (F) and then extended (E); however, the F-E transition occurred at the onset of FWD swing and at the end of BWD swing. For FWD walking, the MTP joint extended at a constant velocity during most of stance as the cat's weight rotated forward over the paw. During the unweighting phase at the end of stance, the MTP joint flexed rapidly before paw lift off. For BWD walking, the MTP joint extended briefly at stance onset (similar to a yield) and then flexed at a constant velocity as the cat's weight rotated backward over the paw. At the end of stance, the MTP joint extended and then flexed slightly as the paw was unweighted before paw lift off. 3. For both forms of walking, three of the six muscles tested were recruited just before paw contact and remained active for most (75-80%) of stance for both walking forms: plantaris (PLT), flexor hallucis longus (FHL), and flexor digitorum brevis (FDB). Their recruitment contributed to the flexor

  20. Recreational sport activity after total replacement of the first metatarsophalangeal joint: a prospective study

    PubMed Central

    Daniilidis, Kiriakos; Marinozzi, Andrea; Denaro, Vincenzo; Gosheger, Georg; Pejman, Ziai; Buchhorn, Thomas

    2010-01-01

    First metatarsophalangeal joint replacement is an alternative surgical procedure to arthrodesis in the treatment of moderate-to-severe hallux rigidus. However, few studies have been published about functional outcome after joint reconstructive procedures for hallux rigidus. The purpose of this study was to assess clinical, radiological and functional outcome, with special regard to recreational and sports activity, after first metatarsophalangeal joint replacement in patients affected by hallux rigidus grade III. Twenty-three patients who had undergone total joint replacement of the first metatarsophalangeal joint were examined preoperatively and three, six, 12 and 18 months postoperatively. All patients (mean age of 57.0 ± 3.7 years) received a non-cemented TOEFIT-PLUS™ implant by one surgeon. Clinical scores (AOFAS score and VAS), radiological examination, patient satisfaction and sport participation were used to evaluate treatment outcome and radiolucent lines. The mean AOFAS score showed a significant improvement from 44.6 ± 7.2 points preoperatively to an average of 82.5 ± 14.4 points at last follow-up (p < 0.001). The mean total ROM of the first MTP joint increased from 28.1 ± 4.9 degrees preoperatively to 52.7 ± 15.7 degrees postoperatively (p < 0.001). After surgery, 91.3% of the patients were able to resume at least one recreational activity. Total arthroplasty for the treatment of hallux rigidus in an active patient population revealed good clinical and functional results. However, postoperative recreational sport activity showed a decrease in comparison to the pre-arthritic state. Further follow-up is necessary to quantify loosening risk in active patients after total hallux arthroplasty. PMID:20069300

  1. Recreational sport activity after total replacement of the first metatarsophalangeal joint: a prospective study.

    PubMed

    Daniilidis, Kiriakos; Martinelli, Nicolò; Marinozzi, Andrea; Denaro, Vincenzo; Gosheger, Georg; Pejman, Ziai; Buchhorn, Thomas

    2010-10-01

    First metatarsophalangeal joint replacement is an alternative surgical procedure to arthrodesis in the treatment of moderate-to-severe hallux rigidus. However, few studies have been published about functional outcome after joint reconstructive procedures for hallux rigidus. The purpose of this study was to assess clinical, radiological and functional outcome, with special regard to recreational and sports activity, after first metatarsophalangeal joint replacement in patients affected by hallux rigidus grade III. Twenty-three patients who had undergone total joint replacement of the first metatarsophalangeal joint were examined preoperatively and three, six, 12 and 18 months postoperatively. All patients (mean age of 57.0 ± 3.7 years) received a non-cemented TOEFIT-PLUS™ implant by one surgeon. Clinical scores (AOFAS score and VAS), radiological examination, patient satisfaction and sport participation were used to evaluate treatment outcome and radiolucent lines. The mean AOFAS score showed a significant improvement from 44.6 ± 7.2 points preoperatively to an average of 82.5 ± 14.4 points at last follow-up (p < 0.001). The mean total ROM of the first MTP joint increased from 28.1 ± 4.9 degrees preoperatively to 52.7 ± 15.7 degrees postoperatively (p < 0.001). After surgery, 91.3% of the patients were able to resume at least one recreational activity. Total arthroplasty for the treatment of hallux rigidus in an active patient population revealed good clinical and functional results. However, postoperative recreational sport activity showed a decrease in comparison to the pre-arthritic state. Further follow-up is necessary to quantify loosening risk in active patients after total hallux arthroplasty.

  2. The role of sensory signals from the insect coxa-trochanteral joint in controlling motor activity of the femur-tibia joint.

    PubMed

    Akay, T; Bässler, U; Gerharz, P; Büschges, A

    2001-02-01

    Interjoint coordination in multi-jointed limbs is essential for the generation of functional locomotor patterns. Here we have focused on the role that sensory signals from the coxa-trochanteral (CT) joint play in patterning motoneuronal activity of the femur-tibia (FT) joint in the stick insect middle leg. This question is of interest because when the locomotor system is active, movement signals from the FT joint are known to contribute to patterning of activity of the central rhythm-generating networks governing the CT joint. We investigated the influence of femoral levation and depression on the activity of tibial motoneurons. When the locomotor system was active, levation of the femur often induced a decrease or inactivation of tibial extensor activity while flexor motoneurons were activated. Depression of the femur had no systematic influence on tibial motoneurons. Ablation experiments revealed that this interjoint influence was not mediated by signals from movement and/or position sensitive receptors at the CT joint, i.e., trochanteral hairplate, rhombal hairplate, or internal levator receptor organ. Instead the influence was initiated by sensory signals from a field of campaniform sensillae, situated on the proximal femur (fCS). Selective stimulation of these fCS produced barrages of inhibitory postsynaptic potentials (IPSPs) in tibial extensor motoneurons and activated tibial flexor motoneurons. During pharmacologically activated rhythmic activity of the otherwise isolated mesothoracic ganglion (pilocarpine, 5 x 10(-4) M), deafferented except for the CT joint, levation of the femur as well had an inhibitory influence on tibial extensor motoneurons. However, the influence of femoral levation on the rhythm generated was rather labile and only sometimes a reset of the rhythm was induced. In none of the preparations could entrainment of rhythmicity by femoral movement be achieved, suggesting that sensory signals from the CT joint only weakly affect central

  3. Neck rotation modulates flexion synergy torques, indicating an ipsilateral reticulospinal source for impairment in stroke.

    PubMed

    Ellis, Michael D; Drogos, Justin; Carmona, Carolina; Keller, Thierry; Dewald, Julius P A

    2012-12-01

    The effect of reticular formation excitability on maximum voluntary torque (MVT) generation and associated muscle activation at the shoulder and elbow was investigated through natural elicitation (active head rotation) of the asymmetric tonic neck reflex (ATNR) in 26 individuals with stroke and 9 age-range-matched controls. Isometric MVT generation at the shoulder and elbow was quantified with the head rotated (face pointing) contralateral and ipsilateral to the paretic (stroke) and dominant (control) arm. Given the dominance of abnormal torque coupling of elbow flexion with shoulder abduction (flexion synergy) in stroke and well-developed animal models demonstrating a linkage between reticular formation and ipsilateral elbow flexors and shoulder abductors, we hypothesized that constituent torques of flexion synergy, specifically elbow flexion and shoulder abduction, would increase with contralateral head rotation. The findings of this investigation support this hypothesis. Increases in MVT for three of four flexion synergy constituents (elbow flexion, shoulder abduction, and shoulder external rotation) were observed during contralateral head rotation only in individuals with stroke. Electromyographic data of the associated muscle coactivations were nonsignificant but are presented for consideration in light of a likely underpowered statistical design for this specific variable. This study not only provides evidence for the reemergence of ATNR following stroke but also indicates a common neuroanatomical link, namely, an increased reliance on ipsilateral reticulospinal pathways, as the likely mechanism underlying the expression of both ATNR and flexion synergy that results in the loss of independent joint control.

  4. STS payloads mission control study continuation phase A-1. Volume 2-C, task 3: Identification of joint activities and estimation of resources in preparation for joint flight operations

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Payload mission control concepts are developed for real time flight operations of STS. Flight planning, training, simulations, and other flight preparations are included. Payload activities for the preflight phase, activity sequences and organizational allocations, and traffic and experience factors to establish composite man-loading for joint STS payload activities are identified for flight operations from 1980 to 1985.

  5. [The effects of exercise and sports activities on bone and joint morbidities.

    PubMed

    Yoshiya, Shinichi

    Exercise and sports activities can afford mechanical stimuli to the bone and joint tissues which are required to maintain the tissue properties. Moreover, physical exercise is an important part of the management of bone and joint morbidities such as osteoporosis, osteoarthritis, and low back pain. On the other hand, excessive mechanical load involved in exercise and sports activities can be harmful potentially causing overuse injuries of the musculoskeletal tissues. Especially, safety margin for the amount of acceptable mechanical stress is narrow in the elderly due to preexisting musculoskeletal problems. Preparticipation medical checkup and construction of appropriate exercise program based on the physical assessment are mandatory to prevent overload applied to the bone and joint tissues.

  6. Single-interface Casimir torque

    NASA Astrophysics Data System (ADS)

    Morgado, Tiago A.; Silveirinha, Mário G.

    2016-10-01

    A different type of Casimir-type interaction is theoretically predicted: a single-interface torque at a junction of an anisotropic material and a vacuum or another material system. The torque acts to reorient the polarizable microscopic units of the involved materials near the interface, and thus to change the internal structure of the materials. The single-interface torque depends on the zero-point energy of the interface localized and extended modes. Our theory demonstrates that the single-interface torque is essential to understand the Casimir physics of material systems with anisotropic elements and may influence the orientation of the director of nematic liquid crystals.

  7. Torque feedback transmission

    SciTech Connect

    Whalen, B.L.

    1987-01-20

    This patent describes an infinitely variable transmission of inline configuration for interconnecting a primer mover with a load for clutch free operation in a range of speed including hydraulic neutral comprising: a. planetary gear train means having a ring gear, planetary gears supported by a planetary gear carrier, and a sun gear, the sun gear being connected mechanically to the load, output shaft means for joining the sun gear to the load; b. variable torque feedback means comprising (i) a variable displacement hydraulic motor whose rotor shaft is in line with the output shaft means and drivingly connected to the prime mover and the planetary gear carrier during the full range of operation of the transmission, and (ii) a fixed displacement hydraulic pump connected hydraulically to the motor, the rotor shaft of the pump being connected mechanically to the ring gear and being axially displaced from the output shaft means; c. means for adjusting the displacement volume within the hydraulic motor for controlling the torque feedback in the transmission to provide infinitely variable coupling between the prime mover and the load over the full range of the transmission including hydraulic neutral; d. a speed reducer between the primer mover and the motor rotor shaft and a speed multiplier between the sun gear and the load; and e. mechanical transmission assembly means between the speed multiplier and the load in line with the motor rotor shaft and the output shaft means for providing selection of drive, reverse, park, and neutral.

  8. Joint contrast optimization and object segmentation in active polarimetric images.

    PubMed

    Anna, Guillaume; Bertaux, Nicolas; Galland, Frédéric; Goudail, François; Dolfi, Daniel

    2012-08-15

    We present a method for automatic target detection based on the iterative interplay between an active polarimetric imager with adaptive capabilities and a snake-based image segmentation algorithm. It successfully addresses the difficult situations where the target and the background differ only by their polarimetric properties. This method illustrates the benefits of integrating digital processing algorithms at the heart of the image acquisition process rather than using them only for postprocessing.

  9. Processes and Outcomes of Joint Activity with E-Books for Promoting Kindergarteners' Emergent Literacy

    ERIC Educational Resources Information Center

    Shamir, Adina

    2009-01-01

    This research investigated the effects of an educational electronic book (e-book) on low socioeconomic status (SES) kindergarteners' emergent literacy while focusing on the relationship between process and outcomes during joint learning. The sample (96 kindergarteners, aged five to six) was randomly assigned to experimental (e-book activation) and…

  10. Flight controllers from Soviet Union in joint simulation activity at JSC

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A group of flight controllers from the Soviet Union take part in Apollo Soyuz Test Project (ASTP) joint simulation activity at JSC. They are in one of the support rooms in the Mission Control Center. The simulations are part of the preparations for the U.S.-U.S.S.R. ASTP docking in Earth orbit mission.

  11. 15 CFR 296.9 - Activities not permitted for joint ventures.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false Activities not permitted for joint ventures. 296.9 Section 296.9 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE NIST EXTRAMURAL PROGRAMS...

  12. 15 CFR 296.9 - Activities not permitted for joint ventures.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Activities not permitted for joint ventures. 296.9 Section 296.9 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE NIST EXTRAMURAL PROGRAMS...

  13. 15 CFR 296.9 - Activities not permitted for joint ventures.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false Activities not permitted for joint ventures. 296.9 Section 296.9 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE NIST EXTRAMURAL PROGRAMS...

  14. 15 CFR 296.9 - Activities not permitted for joint ventures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Activities not permitted for joint ventures. 296.9 Section 296.9 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE NIST EXTRAMURAL PROGRAMS...

  15. A Joint Learning Activity in Process Control and Distance Collaboration between Future Engineers and Technicians

    ERIC Educational Resources Information Center

    Deschênes, Jean-Sebastien; Barka, Noureddine; Michaud, Mario; Paradis, Denis; Brousseau, Jean

    2013-01-01

    A joint learning activity in process control is presented, in the context of a distance collaboration between engineering and technical-level students, in a similar fashion as current practices in the industry involving distance coordination and troubleshooting. The necessary infrastructure and the setup used are first detailed, followed by a…

  16. The development of the disease activity score (DAS) and the disease activity score using 28 joint counts (DAS28).

    PubMed

    van Riel, P L C M

    2014-01-01

    In rheumatoid arthritis, disease activity cannot be measured using a single variable. The Disease Activity Score (DAS) has been developed as a quantitative index to be able to measure, study and manage disease activity in RA in daily clinical practice, clinical trials, and long term observational studies. The DAS is a continuous measure of RA disease activity that combines information from swollen joints, tender joints, acute phase response and patient self-report of general health. Cut points were developed to classify patients in remission, as well as low, moderate, and severe disease activity in the 1990s. DAS-based EULAR response criteria were primarily developed to be used in clinical trials to classify individual patients as non-, moderate, or good responders, depending on the magnitude of change and absolute level of disease activity at the conclusion of the test.

  17. Torque control for electric motors

    NASA Technical Reports Server (NTRS)

    Bernard, C. A.

    1980-01-01

    Method for adjusting electric-motor torque output to accomodate various loads utilizes phase-lock loop to control relay connected to starting circuit. As load is imposed, motor slows down, and phase lock is lost. Phase-lock signal triggers relay to power starting coil and generate additional torque. Once phase lock is recoverd, relay restores starting circuit to its normal operating mode.

  18. Planetary Torque in 3D Isentropic Disks

    NASA Astrophysics Data System (ADS)

    Fung, Jeffrey; Masset, Frédéric; Lega, Elena; Velasco, David

    2017-03-01

    Planetary migration is inherently a three-dimensional (3D) problem, because Earth-size planetary cores are deeply embedded in protoplanetary disks. Simulations of these 3D disks remain challenging due to the steep resolution requirements. Using two different hydrodynamics codes, FARGO3D and PEnGUIn, we simulate disk–planet interaction for a one to five Earth-mass planet embedded in an isentropic disk. We measure the torque on the planet and ensure that the measurements are converged both in resolution and between the two codes. We find that the torque is independent of the smoothing length of the planet’s potential (r s), and that it has a weak dependence on the adiabatic index of the gaseous disk (γ). The torque values correspond to an inward migration rate qualitatively similar to previous linear calculations. We perform additional simulations with explicit radiative transfer using FARGOCA, and again find agreement between 3D simulations and existing torque formulae. We also present the flow pattern around the planets that show active flow is present within the planet’s Hill sphere, and meridional vortices are shed downstream. The vertical flow speed near the planet is faster for a smaller r s or γ, up to supersonic speeds for the smallest r s and γ in our study.

  19. Modelling and predicting hidden solder joint shape using active thermography and parametric numerical analysis

    NASA Astrophysics Data System (ADS)

    Giron Palomares, Jose Benjamin; Hsieh, Sheng-Jen

    2014-05-01

    A methodology based on active infrared thermography to study and characterize hidden solder joint shapes on a multi cover PCB assembly was investigated. A numerical model was developed to simulate the active thermography methodology and was proven to determine the grand average cooling rates with maximum errors of 8.85% (one cover) and 13.36% (two covers). A parametric analysis was performed by varying the number of covers, heat flux provided, and the amount of heating time. Grand average cooling rate distances among contiguous solder joint shapes, as well as solder joints discriminability, were determined to be directly proportional to heat flux, and inversely proportional to the number of covers and heating time. Finally, a mathematical model was developed to determine the appropriate total amount of energy needed to discriminate among hidden solder joints with a "good" discriminability for one and two covers, and a "regular" discriminability for up to five covers. The mathematical model was proven to predict the total amount of energy to achieve a "good" discriminability for one cover within a 10% of error with respect to the experimental active thermography model.

  20. Joint dependent passive stiffness in paretic and contralateral limbs of spastic patients with hemiparetic stroke.

    PubMed Central

    Given, J D; Dewald, J P; Rymer, W Z

    1995-01-01

    Torque-angle relations at the elbow and ankle joints of relaxed normal controls and patients with hemiparetic stroke were compared. Low velocity flexion/hold/extension angular perturbations were applied to the joint under examination. The resulting torque-angle profiles described a hysteresis loop with similar slopes during the extension and flexion stages but separated by a vertical torque offset. Torque-angle responses obtained in the absence of significant muscle activation, as recorded by surface electromyographic activity, were designated as passive. Elbow passive stiffness estimates were calculated from the slope of the torque-angle response during the flexion stage of the perturbation. The elbow torque-angle plots exhibited linear passive stiffness with magnitude significantly lower than the passive stiffness of the ankle in both normal subjects and spastic patients. Changing ramp velocity had no significant effect on the passive torque-angle hysteresis loop at the elbow. A comparison of the torque-angle relations between hemiparetic spastic and normal control arms showed no significant differences in passive stiffness. Furthermore, no significant differences were found between paretic and contralateral upper limbs of a given hemiparetic subject. By contrast, significant differences in the torque-angle hysteresis loop were present between the paretic and contralateral ankles in all hemiparetic patients tested. These differences were more significant during dorsiflexion, and therefore seem to be related to preferential changes in mechanical properties of plantar flexor muscles. It is hypothesised that the differences in the torque-angle hysteresis loop between elbow and angle joints are related primarily to the larger amount of connective tissue in the calf muscles, as well as to a larger total physiological cross sectional area of calf muscles compared with elbow muscles. It is further hypothesized that the preferential increases in passive stiffness at the

  1. The effects of powered ankle-foot orthoses on joint kinematics and muscle activation during walking in individuals with incomplete spinal cord injury

    PubMed Central

    Sawicki, Gregory S; Domingo, Antoinette; Ferris, Daniel P

    2006-01-01

    Background Powered lower limb orthoses could reduce therapist labor during gait rehabilitation after neurological injury. However, it is not clear how patients respond to powered assistance during stepping. Patients might allow the orthoses to drive the movement pattern and reduce their muscle activation. The goal of this study was to test the effects of robotic assistance in subjects with incomplete spinal cord injury using pneumatically powered ankle-foot orthoses. Methods Five individuals with chronic incomplete spinal cord injury (ASIA C-D) participated in the study. Each subject was fitted with bilateral ankle-foot orthoses equipped with artificial pneumatic muscles to power ankle plantar flexion. Subjects walked on a treadmill with partial bodyweight support at four speeds (0.36, 0.54, 0.72 and 0.89 m/s) under three conditions: without wearing orthoses, wearing orthoses unpowered (passively), and wearing orthoses activated under pushbutton control by a physical therapist. Subjects also attempted a fourth condition wearing orthoses activated under pushbutton control by them. We measured joint angles, electromyography, and orthoses torque assistance. Results A therapist quickly learned to activate the artificial pneumatic muscles using the pushbuttons with the appropriate amplitude and timing. The powered orthoses provided ~50% of peak ankle torque. Ankle angle at stance push-off increased when subjects walked with powered orthoses versus when they walked with passive-orthoses (ANOVA, p < 0.05). Ankle muscle activation amplitudes were similar for powered and passive-orthoses conditions except for the soleus (~13% lower for powered condition; p < 0.05). Two of the five subjects were able to control the orthoses themselves using the pushbuttons. The other three subjects found it too difficult to coordinate pushbutton timing. Orthoses assistance and maximum ankle angle at push-off were smaller when the subject controlled the orthoses compared to when the therapist

  2. The Spin Torque Lego - from spin torque nano-devices to advanced computing architectures

    NASA Astrophysics Data System (ADS)

    Grollier, Julie

    2013-03-01

    Spin transfer torque (STT), predicted in 1996, and first observed around 2000, brought spintronic devices to the realm of active elements. A whole class of new devices, based on the combined effects of STT for writing and Giant Magneto-Resistance or Tunnel Magneto-Resistance for reading has emerged. The second generation of MRAMs, based on spin torque writing : the STT-RAM, is under industrial development and should be out on the market in three years. But spin torque devices are not limited to binary memories. We will rapidly present how the spin torque effect also allows to implement non-linear nano-oscillators, spin-wave emitters, controlled stochastic devices and microwave nano-detectors. What is extremely interesting is that all these functionalities can be obtained using the same materials, the exact same stack, simply by changing the device geometry and its bias conditions. So these different devices can be seen as Lego bricks, each brick with its own functionality. During this talk, I will show how spin torque can be engineered to build new bricks, such as the Spintronic Memristor, an artificial magnetic nano-synapse. I will then give hints on how to assemble these bricks in order to build novel types of computing architectures, with a special focus on neuromorphic circuits. Financial support by the European Research Council Starting Grant NanoBrain (ERC 2010 Stg 259068) is acknowledged.

  3. Effect of altering starting length and activation timing of muscle on fiber strain and muscle damage.

    PubMed

    Butterfield, Timothy A; Herzog, Walter

    2006-05-01

    Muscle strain injuries are some of the most frequent injuries in sports and command a great deal of attention in an effort to understand their etiology. These injuries may be the culmination of a series of subcellular events accumulated through repetitive lengthening (eccentric) contractions during exercise, and they may be influenced by a variety of variables including fiber strain magnitude, peak joint torque, and starting muscle length. To assess the influence of these variables on muscle injury magnitude in vivo, we measured fiber dynamics and joint torque production during repeated stretch-shortening cycles in the rabbit tibialis anterior muscle, at short and long muscle lengths, while varying the timing of activation before muscle stretch. We found that a muscle subjected to repeated stretch-shortening cycles of constant muscle-tendon unit excursion exhibits significantly different joint torque and fiber strains when the timing of activation or starting muscle length is changed. In particular, measures of fiber strain and muscle injury were significantly increased by altering activation timing and increasing the starting length of the muscle. However, we observed differential effects on peak joint torque during the cyclic stretch-shortening exercise, as increasing the starting length of the muscle did not increase torque production. We conclude that altering activation timing and muscle length before stretch may influence muscle injury by significantly increasing fiber strain magnitude and that fiber dynamics is a more important variable than muscle-tendon unit dynamics and torque production in influencing the magnitude of muscle injury.

  4. The Research and Training Activities for the Joint Institute for Aeronautics and Acoustics

    NASA Technical Reports Server (NTRS)

    Cantwell, Brian

    1995-01-01

    This proposal requests continued support for the program of activities to be undertaken by the Ames-Stanford Joint Institute for Aeronautics and Acoustics during the period 1 Oct. 1995 - 30 Sept. 1996. The emphasis in this program is on training and research in experimental and computational methods with application to aerodynamics, acoustics and the important interactions between them. The program comprises activities in active flow control, Large Eddy Simulation of jet noise, flap aerodynamics and acoustics and high lift modeling studies. During the proposed period there will be a continued emphasis on the interaction between NASA Ames, Stanford University and Industry, particularly in connection with the high lift activities.

  5. Design and use of brushless dc motor without detent torque

    NASA Astrophysics Data System (ADS)

    Wavre, N.

    1990-03-01

    Two applications of motors which cannot accept a residual detent torque due to the rotor magnets are presented. The first application concerns the joint mechanism of the Synchronous Meteorological Satellite/HERA project. The brushless torque motor drives a reversible harmonic drive with a high gear ratio of 500. The motor is designed to produce a stall torque of 3.0 Nm with a total imput power of 30 W for a total weight of 1.5 kg, with a no load speed of 500 rpm. The second application concerns the driving mechanism of an infrared sensor. The need to take all geometrical and magnetic parameters into consideration in designing space mechanisms is stressed.

  6. Inflammatory synovial fluid microenvironment drives primary human chondrocytes to actively take part in inflammatory joint diseases.

    PubMed

    Röhner, Eric; Matziolis, Georg; Perka, Carsten; Füchtmeier, Bernd; Gaber, Timo; Burmester, Gerd-Rüdiger; Buttgereit, Frank; Hoff, Paula

    2012-06-01

    The role of human chondrocytes in the pathogenesis of cartilage degradation in rheumatic joint diseases has presently gained increasing interest. An active chondrocyte participation in local inflammation may play a role in the initiation and progression of inflammatory joint diseases and in a disruption of cartilage repair mechanisms resulting in cartilage degradation. In the present study, we hypothesized that inflammatory synovial fluid triggers human chondrocytes to actively take part in inflammatory processes in rheumatic joint diseases. Primary human chondrocytes were incubated in synovial fluids gained from patients with rheumatoid arthritis, psoriasis arthritis and reactive arthritis. The detection of vital cell numbers was determined by using Casy Cell Counter System. Apoptosis was measured by Annexin-V and 7AAD staining. Cytokine and chemokine secretion was determined by a multiplex suspension array. Detection of vital cells showed a highly significant decrease in chondrocyte numbers. Flow cytometry demonstrated a significant increase in apoptotic chondrocytes after the incubation. An active secretion of cytokines such as MCP-1 and MIF by chondrocytes was observed. The inflammatory synovial fluid microenvironment mediates apoptosis and cell death of chondrocytes. Moreover, in terms of cytokine secretion, it also induces an active participation of chondrocytes in ongoing inflammation.

  7. Synovial fluid matrix metalloproteinase-2 and -9 activities in dogs suffering from joint disorders.

    PubMed

    Murakami, Kohei; Maeda, Shingo; Yonezawa, Tomohiro; Matsuki, Naoaki

    2016-07-01

    The activity of matrix metalloproteinase (MMP)-2 and MMP-9 in synovial fluids (SF) sampled from dogs with joint disorders was investigated by gelatin zymography and densitometry. Pro-MMP-2 showed similar activity levels in dogs with idiopathic polyarthritis (IPA; n=17) or canine rheumatoid arthritis (cRA; n=4), and healthy controls (n=10). However, dogs with cranial cruciate ligament rupture (CCLR; n=5) presented significantly higher pro-MMP-2 activity than IPA and healthy dogs. Meanwhile, dogs with IPA exhibited significantly higher activity of pro- and active MMP-9 than other groups. Activity levels in pro- and active MMP-9 in cRA and CCLR dogs were not significantly different from those in healthy controls. Different patterns of MMP-2 and MMP-9 activity may reflect the differences in the underlying pathological processes.

  8. Flexible Coordination of Stationary and Mobile Conversations with Gaze: Resource Allocation among Multiple Joint Activities

    PubMed Central

    Mayor, Eric; Bangerter, Adrian

    2016-01-01

    Gaze is instrumental in coordinating face-to-face social interactions. But little is known about gaze use when social interactions co-occur with other joint activities. We investigated the case of walking while talking. We assessed how gaze gets allocated among various targets in mobile conversations, whether allocation of gaze to other targets affects conversational coordination, and whether reduced availability of gaze for conversational coordination affects conversational performance and content. In an experimental study, pairs were videotaped in four conditions of mobility (standing still, talking while walking along a straight-line itinerary, talking while walking along a complex itinerary, or walking along a complex itinerary with no conversational task). Gaze to partners was substantially reduced in mobile conversations, but gaze was still used to coordinate conversation via displays of mutual orientation, and conversational performance and content was not different between stationary and mobile conditions. Results expand the phenomena of multitasking to joint activities. PMID:27822189

  9. An activated energy approach for accelerated testing of the deformation of UHMWPE in artificial joints.

    PubMed

    Galetz, Mathias Christian; Glatzel, Uwe

    2010-05-01

    The deformation behavior of ultrahigh molecular polyethylene (UHMWPE) is studied in the temperature range of 23-80 degrees C. Samples are examined in quasi-static compression, tensile and creep tests to determine the accelerated deformation of UHMWPE at elevated temperatures. The deformation mechanisms under compression load can be described by one strain rate and temperature dependent Eyring process. The activation energy and volume of that process do not change between 23 degrees C and 50 degrees C. This suggests that the deformation mechanism under compression remains stable within this temperature range. Tribological tests are conducted to transfer this activated energy approach to the deformation behavior under loading typical for artificial knee joints. While this approach does not cover the wear mechanisms close to the surface, testing at higher temperatures is shown to have a significant potential to reduce the testing time for lifetime predictions in terms of the macroscopic creep and deformation behavior of artificial joints.

  10. Plantar flexor moment arm and muscle volume predict torque-generating capacity in young men.

    PubMed

    Baxter, Josh R; Piazza, Stephen J

    2014-03-01

    Muscle volume is known to correlate with maximal joint torque in humans, but the role of muscle moment arm in determining maximal torque is less clear. Moderate correlations have been reported between maximal isometric knee extensor torque and knee extensor moment arm, but no such observations have been made for the ankle joint. It has been suggested that smaller muscle moment arms may enhance force generation at high rates of joint rotation, but this has not yet been observed for ankle muscles in vivo. The purpose of the present study was to correlate plantar flexor moment arm and plantar flexor muscle volume with maximal plantar flexor torque measured at different rates of plantar flexion. Magnetic resonance imaging was used to quantify the plantar flexor moment arm and muscle volume of the posterior compartment in 20 healthy young men. Maximal plantar flexor torque was measured isometrically and at three plantar flexion speeds using an isokinetic dynamometer. Plantar flexor torque was significantly correlated with muscle volume (0.222 < R(2) < 0.322) and with muscle moment arm at each speed (0.323 < R(2) < 0.494). While muscle volume was strongly correlated with body mass and stature, moment arm was not. The slope of the torque-moment arm regression line decreased as the rate of joint rotation increased, indicating that subjects with small moment arms experienced smaller reductions in torque at high speeds. The findings of this study suggest that plantar flexor moment arm is a determinant of joint strength that is at least as important as muscle size.

  11. Extension joints: a tool to infer the active stress field orientation (case study from southern Italy)

    NASA Astrophysics Data System (ADS)

    De Guidi, Giorgio; Caputo, Riccardo; Scudero, Salvatore; Perdicaro, Vincenzo

    2013-04-01

    An intense tectonic activity in eastern Sicily and southern Calabria is well documented by the differential uplift of Late Quaternary coastlines and by the record of the strong historical earthquakes. The extensional belt that crosses this area is dominated by a well established WNW-ESE-oriented extensional direction. However, this area is largely lacking of any structural analysis able to define the tectonics at a more local scale. In the attempt to fill this gap of knowledge, we carried out a systematic analysis of extension joint sets. In fact, the systematic field collection of these extensional features, coupled with an appropriate inversion technique, allows to determine the characteristic of the causative tectonic stress field. Joints are defined as outcrop-scale mechanical discontinuities showing no evidence of shear motion and being originated as purely extensional fractures. Such tectonic features are one of the most common deformational structures in every tectonic environment and particularly abundant in the study area. A particular arrangement of joints, called "fracture grid-lock system", and defined as an orthogonal joint system where mutual abutting and crosscutting relationships characterize two geologically coeval joint sets, allow to infer the direction and the magnitude of the tectonic stress field. We performed the analyses of joints only on Pleistocene deposits of Eastern Sicily and Southern Calabria. Moreover we investigated only calcarenite sediments and cemented deposits, avoiding claysh and loose matrix-supported clastic sediments where the deformation is generally accomodated in a distributed way through the relative motion between the single particles. In the selection of the sites, we also took into account the possibility to clearly observe the geometric relationships among the joints. For this reason we chose curvilinear road cuts or cliffs, wide coastal erosional surfaces and quarries. The numerical inversions show a similar stress

  12. The Effect of Manipulating Subject Mass on Lower Extremity Torque Patterns During Locomotion

    NASA Technical Reports Server (NTRS)

    DeWitt, John K.; Cromwell, Ronita L.; Hagan, R. Donald

    2007-01-01

    During locomotion, humans adapt their motor patterns to maintain coordination despite changing conditions (Reisman et al., 2005). Bernstein (1967) proposed that in addition to the present state of a given joint, other factors, including limb inertia and velocity, must be taken into account to allow proper motion to occur. During locomotion with added mass counterbalanced using vertical suspension to maintain body weight, vertical ground reaction forces (GRF's) increase during walking but decrease during running, suggesting that adaptation may be velocity-specific (De Witt et al., 2006). It is not known, however, how lower extremity joint torques adapt to changes in inertial forces. The purpose of this investigation was to examine the effects of increasing body mass while maintaining body weight upon lower-limb joint torque during walking and running. We hypothesized that adaptations in joint torque patterns would occur with the addition of body mass.

  13. Role of gastrocnemius activation in knee joint biomechanics: gastrocnemius acts as an ACL antagonist.

    PubMed

    Adouni, M; Shirazi-Adl, A; Marouane, H

    2016-01-01

    Gastrocnemius is a premier muscle crossing the knee, but its role in knee biomechanics and on the anterior cruciate ligament (ACL) remains less clear when compared to hamstrings and quadriceps. The effect of changes in gastrocnemius force at late stance when it peaks on the knee joint response and ACL force was initially investigated using a lower extremity musculoskeletal model driven by gait kinematics-kinetics. The tibiofemoral joint under isolated isometric contraction of gastrocnemius was subsequently analyzed at different force levels and flexion angles (0°-90°). Changes in gastrocnemius force at late stance markedly influenced hamstrings forces. Gastrocnemius acted as ACL antagonist by substantially increasing its force. Simulations under isolated contraction of gastrocnemius confirmed this role at all flexion angles, in particular, at extreme knee flexion angles (0° and 90°). Constraint on varus/valgus rotations substantially decreased this effect. Although hamstrings and gastrocnemius are both knee joint flexors, they play opposite roles in respectively protecting or loading ACL. Although the quadriceps is also recognized as antagonist of ACL, at larger joint flexion and in contrast to quadriceps, activity in gastrocnemius substantially increased ACL forces (anteromedial bundle). The fact that gastrocnemius is an antagonist of ACL should help in effective prevention and management of ACL injuries.

  14. Quick torque coupling

    DOEpatents

    Luft, Peter A.

    2009-05-12

    A coupling for mechanically connecting modular tubular struts of a positioning apparatus or space frame, comprising a pair of toothed rings (10, 12) attached to separate strut members (16), the teeth (18, 20) of the primary rings (10, 12) mechanically interlocking in both an axial and circumferential manner, and a third part comprising a sliding, toothed collar (14) the teeth (22) of which interlock the teeth (18, 20) of the primary rings (10, 12), preventing them from disengaging, and completely locking the assembly together. A secondary mechanism provides a nesting force for the collar, and/or retains it. The coupling is self-contained and requires no external tools for installation, and can be assembled with gloved hands in demanding environments. No gauging or measured torque is required for assembly. The assembly can easily be visually inspected to determine a "go" or "no-go" status. The coupling is compact and relatively light-weight. Because of it's triply interlocking teeth, the connection is rigid. The connection does not primarily rely on clamps, springs or friction based fasteners, and is therefore reliable in fail-safe applications.

  15. Deformable micro torque swimmer

    NASA Astrophysics Data System (ADS)

    Ishikawa, Takuji; Tanaka, Tomoyuki; Omori, Toshihiro; Imai, Yohsuke

    2015-11-01

    We investigated the deformation of a ciliate swimming freely in a fluid otherwise at rest. The cell body was modeled as a capsule with a hyper elastic membrane enclosing Newtonian fluid. Thrust forces due to the ciliary beat were modeled as torques distributed above the cell body. Effects of the membrane elasticity, the aspect ratio of cell's reference shape and the density difference between the cell and the surrounding fluid were investigated. The results showed that the cell deformed like heart shape when Capillary number (Ca) was sufficiently large, and the swimming velocity decreased as Ca was increased. The gravity effect on the membrane tension suggested that the upwards and downwards swimming velocities of Paramecium might be reglated by the calcium ion channels distributed locally around the anterior end. Moreover, the gravity induced deformation made a cell directed vertically downwards, which resulted in a positive geotaxis like behavior with physical origin. These results are important to understand physiology of ciliate's biological responses to mechanical stimuli.

  16. Modeling and Implementation of Solder-activated Joints for Single Actuator, Centimeter-Scale Robotic Mechanisms

    DTIC Science & Technology

    2010-06-01

    mechanisms may be built and actuated to perform a multiplicity of tasks using PCM-activated joints. The robot was developed under the Chemical Robots DARPA ...components. 4.1.1 Chemical Robots Program The Chemical Robots (ChemBots) program is funded by the DARPA Defense Sciences Office. The goal of the program...perform tasks in these hostile and hard to reach spaces safely, covertly, and efficiently [26]. To develop this new class of robots, DARPA asked for

  17. Investigating activity of masticatory muscles in patients with hypermobile temporomandibular joints by using EMG

    PubMed Central

    Davoudi, Amin; Rybalov, Oleg; Shadmehr, Elham; Hatami, Amin

    2015-01-01

    Background Temporomandibular joint hypermobility (TMJH) can manifest higher range of motions in mandible. The aim of this study was to investigate and compare the activity of masticatory muscle of TMJs in healthy individuals and patients with mild, moderate and severe TMJH. Material and Methods In this clinical study, 69 patients (between the ages of 22 to 42) with manifestation of TMJH were included. The patients were divided into three groups based on their maximum mouth opening (MMO): (light) with MMO of 50-55 mm; (moderate) with MMO between 55 to 65 mm; and (severe) with MMO >65 mm. Also, 20 healthy people with profiled tomography in the last 6 months were invited as control group (healthy) with normal MMO (<50 mm). All the groups subjected to electromyogram (EMG) in 2 steps: maximal voluntary clenching (MVC) of the jaws; and during chewing of bread by using one side of the jaws voluntary. The collected data were analyzed by Student T-test and Chi-Square tests using SPSS software version 15 at significant level of 0.05. Results Both TMJs of light, moderate and severe groups showed significant differences in frequency, time of activity and rest in comparison with healthy group during chewing and MVC (all p values < 0.01). Conclusions Masticatory muscles activity reduced in relation with the severity of TMJH and higher excessive mouth opening. Key words:Electromyography, joint hypermobility, mouth opening, tempormandibular joint. PMID:26155352

  18. Zero torque gear head wrench

    NASA Technical Reports Server (NTRS)

    Mcdougal, A. R.; Norman, R. M. (Inventor)

    1976-01-01

    A gear head wrench particularly suited for use in applying torque to bolts without transferring torsional stress to bolt-receiving structures is introduced. The wrench is characterized by a coupling including a socket, for connecting a bolt head with a torque multiplying gear train, provided within a housing having an annulus concentrically related to the socket and adapted to be coupled with a spacer interposed between the bolt head and the juxtaposed surface of the bolt-receiving structure for applying a balancing counter-torque to the spacer as torque is applied to the bolt head whereby the bolt-receiving structure is substantially isolated from torsional stress. As a result of the foregoing, the operator of the wrench is substantially isolated from any forces which may be imposed.

  19. Torque Simulator for Rotating Systems

    NASA Technical Reports Server (NTRS)

    Davis, W. T.

    1982-01-01

    New torque brake simulates varying levels of friction in bearings of rotating body. Rolling-tail torque brake uses magnetic force to produce friction between rotating part and stationary part. Simulator electronics produce positive or negative feedback signal, depending on direction of rotation. New system allows for first time in-depth study of effects of tail-fin spin rates on pitch-, yaw-, and roll-control characteristics.

  20. Torque-Summing Brushless Motor

    NASA Technical Reports Server (NTRS)

    Vaidya, J. G.

    1986-01-01

    Torque channels function cooperatively but electrically independent for reliability. Brushless, electronically-commutated dc motor sums electromagnetic torques on four channels and applies them to single shaft. Motor operates with any combination of channels and continues if one or more of channels fail electrically. Motor employs single stator and rotor and mechanically simple; however, each of channels electrically isolated from other so that failure of one does not adversely affect others.

  1. 14 CFR 27.361 - Engine torque.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Engine torque. 27.361 Section 27.361... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.361 Engine torque. (a) For turbine engines, the limit torque may not be less than the highest of— (1) The mean torque for...

  2. 14 CFR 27.361 - Engine torque.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine torque. 27.361 Section 27.361... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.361 Engine torque. (a) For turbine engines, the limit torque may not be less than the highest of— (1) The mean torque for...

  3. 14 CFR 27.361 - Engine torque.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Engine torque. 27.361 Section 27.361... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.361 Engine torque. (a) For turbine engines, the limit torque may not be less than the highest of— (1) The mean torque for...

  4. 14 CFR 27.361 - Engine torque.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine torque. 27.361 Section 27.361... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.361 Engine torque. (a) For turbine engines, the limit torque may not be less than the highest of— (1) The mean torque for...

  5. 14 CFR 27.361 - Engine torque.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine torque. 27.361 Section 27.361... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.361 Engine torque. (a) For turbine engines, the limit torque may not be less than the highest of— (1) The mean torque for...

  6. Variable magnetic circuit torque sensor

    NASA Astrophysics Data System (ADS)

    Lemarquand, G.; Lemarquand, V.

    1991-11-01

    This paper presents an original torque sensor structure using the properties of magnetic circuits, including permanent magnets. The torque is measured through the torsion of the transmitting shaft. The torsion is proportional to the torque. Considering two points of the shaft on the same line in absence of torque, the information is given by the twisting angle in the presence of a torque. A rotating magnetic circuit yields an angle representative signal. This circuit is deformed by the shaft torsion. The reluctance varies and so does the magnet operating point. The induction is measured in an airgap by a statoric galvanomagnetic device. The magnetic field source is an axial permanent magnet ring. Two iron-toothed rings, fixed to the driving and driven part of the shaft, respectively, and separated by an airgap make up the variable part of the magnetic circuit. The teeth get out of line whenever a torque is applied. The galvanomagnetic device measures an uniform induction and so delivers a modulation free signal, i.e., rotation independent. Because of the periodic toothed structure, the induction varies periodically with the twisting angle. The sense of the variation is the same over half a period or half a pitch. The variation form depends on the teeth design. Operating interval is to be chosen equal to or smaller than the half pitch.

  7. Pressurized fluid torque driver control and method

    NASA Astrophysics Data System (ADS)

    Cook, Joseph S., Jr.

    1994-08-01

    Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

  8. Pressurized fluid torque driver control and method

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1994-01-01

    Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

  9. Comparing brain activation associated with isolated upper and lower limb movement across corresponding joints.

    PubMed

    Luft, Andreas R; Smith, Gerald V; Forrester, Larry; Whitall, Jill; Macko, Richard F; Hauser, Till-Karsten; Goldberg, Andrew P; Hanley, Daniel F

    2002-10-01

    It was shown recently that functional activation across brain motor areas during locomotion and foot movements are similar but differ substantially from activation related to upper extremity movement (Miyai [2001]: Neuroimage 14:1186-1192). The activation pattern may be a function of the behavioral context of the movement rather than of its mechanical properties. We compare motor system activation patterns associated with isolated single-joint movement of corresponding joints in arm and leg carried out in equal frequency and range. Eleven healthy volunteers underwent BOLD-weighted fMRI while performing repetitive elbow or knee extension/flexion. To relate elbow and knee activation to the well-described patterns of finger movement, serial finger-to-thumb opposition was assessed in addition. After identifying task-related voxels using statistical parametric mapping, activation was measured in five regions of interest (ROI; primary motor [M1] and somatosensory cortex [S1], premotor cortex, supplementary motor area [SMA] divided into preSMA and SMA-proper, and cerebellum). Differences in the degree of activation across ROIs were found between elbow and knee movement. SMA-proper activation was prominent for knee, but almost absent for elbow movement (P < 0.05); finger movement produced small but constant SMA-proper activation. Ipsilateral M1 activation was detected during knee and finger movement, but was absent for the elbow task (P < 0.05). Knee movement showed less lateralization in M1 and S1 than other tasks (P < 0.05). The data demonstrate that central motor structures contribute differently to isolated elbow and knee movement. Activation during knee movement shows similarities to gait-related activation patterns.

  10. In-vitro and in-vivo imaging of MMP activity in cartilage and joint injury.

    PubMed

    Fukui, Tomoaki; Tenborg, Elizabeth; Yik, Jasper H N; Haudenschild, Dominik R

    2015-05-08

    Non-destructive detection of cartilage-degrading activities represents an advance in osteoarthritis (OA) research, with implications in studies of OA pathogenesis, progression, and intervention strategies. Matrix metalloproteinases (MMPs) are principal cartilage degrading enzymes that contribute to OA pathogenesis. MMPSense750 is an in-vivo fluorimetric imaging probe with the potential to continuously and non-invasively trace real-time MMP activities, but its use in OA-related research has not been reported. Our objective is to detect and characterize the early degradation activities shortly after cartilage or joint injury with MMPSense750. We determined the appropriate concentration, assay time, and linear range using various concentrations of recombinant MMPs as standards. We then quantified MMP activity from cartilage explants subjected to either mechanical injury or inflammatory cytokine treatment in-vitro. Finally, we performed in-vivo MMP imaging of a mouse model of post-traumatic OA. Our in-vitro results showed that the optimal assay time was highly dependent on the MMP enzyme. In cartilage explant culture media, mechanical impact or cytokine treatment increased MMP activity. Injured knees of mice showed significantly higher fluorescent signal than uninjured knees. We conclude that MMPSense750 detects human MMP activities and can be used for in-vitro study with cartilage, as well as in-vivo studies of knee injury, and can offering real-time insight into the degradative processes that occurring within the joint before structural changes become evident radiographically.

  11. The surface geometry of inherited joint and fracture trace patterns resulting from active and passive deformation

    NASA Technical Reports Server (NTRS)

    Podwysocki, M. H.; Gold, D. P.

    1974-01-01

    Hypothetical models are considered for detecting subsurface structure from the fracture or joint pattern, which may be influenced by the structure and propagated to the surface. Various patterns of an initially orthogonal fracture grid are modeled according to active and passive deformation mechanisms. In the active periclinal structure with a vertical axis, fracture frequency increased both over the dome and basin, and remained constant with decreasing depth to the structure. For passive periclinal features such as a reef or sand body, fracture frequency is determined by the arc of curvature and showed a reduction over the reefmound and increased over the basin.

  12. Influence of electrical stimulation on hip joint adductor muscle activity during maximum effort.

    PubMed

    Nakano, Sota; Wada, Chikamune

    2016-05-01

    [Purpose] This study investigated whether hip adductor activity was influenced by electrical stimulation of the tensor fascia lata muscle. [Subjects and Methods] The subjects were 16 nondisabled males. Each subject was asked to adduct the hip joint with maximum effort. The electromyogram of the adductor longus was recorded under two experimental conditions, with and without electrical stimulation of the tensor fascia lata. [Results] In the presence of electrical stimulation, muscle activity decreased to 72.9% (57.8-89.3%) of that without stimulation. [Conclusion] These results suggested that inactivation of the adductor group was promoted by electrical stimulation of the tensor fascia lata.

  13. Influence of electrical stimulation on hip joint adductor muscle activity during maximum effort

    PubMed Central

    Nakano, Sota; Wada, Chikamune

    2016-01-01

    [Purpose] This study investigated whether hip adductor activity was influenced by electrical stimulation of the tensor fascia lata muscle. [Subjects and Methods] The subjects were 16 nondisabled males. Each subject was asked to adduct the hip joint with maximum effort. The electromyogram of the adductor longus was recorded under two experimental conditions, with and without electrical stimulation of the tensor fascia lata. [Results] In the presence of electrical stimulation, muscle activity decreased to 72.9% (57.8–89.3%) of that without stimulation. [Conclusion] These results suggested that inactivation of the adductor group was promoted by electrical stimulation of the tensor fascia lata. PMID:27313387

  14. The senses of active and passive forces at the human ankle joint.

    PubMed

    Savage, G; Allen, T J; Proske, U

    2015-07-01

    The traditional view of the neural basis for the sense of muscle force is that it is generated at least in part within the brain. Recently it has been proposed that force sensations do not arise entirely centrally and that there is a contribution from peripheral receptors within the contracting muscle. Evidence comes from experiments on thumb flexor and elbow flexor muscles. Here we have studied the sense of force in plantar flexor muscles of the human ankle, looking for further evidence for such a mechanism. The active angle-torque curve was measured for muscles of both legs, and for each muscle, ankle angles were identified on the ascending and descending limbs of the curve where active forces were similar. In a plantar flexion force matching task, subjects were asked to match the force in one foot, generated on the ascending limb of the curve, with force in the other foot, generated on the descending limb. It was hypothesised that despite active forces being similar, the sensation generated in the more stretched muscle should be greater because of the contribution from its peripheral stretch receptors, leading to an overestimation of the force in the stretched muscle. It was found that provided that the comparison was between active forces, there was no difference in the forces generated by the two legs, supporting the central hypothesis for the sense of force. When total forces were matched, including a component of passive force due to muscle stretch, subjects seemed to ignore the passive component. Yet subjects had an acute sense of passive force, provided that the muscles remained relaxed. It was concluded that subjects had two senses, a sense of active force, generated centrally, and a sense of passive force, or perhaps muscle stretch, generated within the muscle itself.

  15. Constant torque in flagellar bacterial motors optimizes space exploration

    NASA Astrophysics Data System (ADS)

    Condat, Carlos A.; di Salvo, Mario E.

    2012-02-01

    Experiments indicate that the torque provided by the bacterial rotary motor is approximately constant over a large range of angular speeds. Constant torque implies that the power spent in active motion is proportional to the instantaneous bacterial speed, if the relation between angular speed and swimming speed is linear. Here we show that a constant torque maximizes the volume of the region explored by a bacterium in a resource-depleted medium. Given that nutrients in the ocean are often concentrated in separate, ephemeral patches, we propose that the observed constancy of the torque may be a trait evolved to maximize bacterial survival in the ocean. We also discuss the dependence of the explored volume with the particular features of the bacterial propulsion mechanism.

  16. Strategy of arm movement control is determined by minimization of neural effort for joint coordination.

    PubMed

    Dounskaia, Natalia; Shimansky, Yury

    2016-06-01

    Optimality criteria underlying organization of arm movements are often validated by testing their ability to adequately predict hand trajectories. However, kinematic redundancy of the arm allows production of the same hand trajectory through different joint coordination patterns. We therefore consider movement optimality at the level of joint coordination patterns. A review of studies of multi-joint movement control suggests that a 'trailing' pattern of joint control is consistently observed during which a single ('leading') joint is rotated actively and interaction torque produced by this joint is the primary contributor to the motion of the other ('trailing') joints. A tendency to use the trailing pattern whenever the kinematic redundancy is sufficient and increased utilization of this pattern during skillful movements suggests optimality of the trailing pattern. The goal of this study is to determine the cost function minimization of which predicts the trailing pattern. We show that extensive experimental testing of many known cost functions cannot successfully explain optimality of the trailing pattern. We therefore propose a novel cost function that represents neural effort for joint coordination. That effort is quantified as the cost of neural information processing required for joint coordination. We show that a tendency to reduce this 'neurocomputational' cost predicts the trailing pattern and that the theoretically developed predictions fully agree with the experimental findings on control of multi-joint movements. Implications for future research of the suggested interpretation of the trailing joint control pattern and the theory of joint coordination underlying it are discussed.

  17. Joint associations of alcohol consumption and physical activity with all-cause and cardiovascular mortality.

    PubMed

    Soedamah-Muthu, Sabita S; De Neve, Melissa; Shelton, Nicola J; Tielemans, Susanne M A J; Stamatakis, Emmanuel

    2013-08-01

    Individual associations of alcohol consumption and physical activity with cardiovascular disease are relatively established, but the joint associations are not clear. Therefore, the aim of this study was to examine prospectively the joint associations between alcohol consumption and physical activity with cardiovascular mortality (CVM) and all-cause mortality. Four population-based studies in the United Kingdom were included, the 1997 and 1998 Health Surveys for England and the 1998 and 2003 Scottish Health Surveys. In men and women, respectively, low physical activity was defined as 0.1 to 5 and 0.1 to 4 MET-hours/week and high physical activity as ≥5 and ≥4 MET-hours/week. Moderate or moderately high alcohol intake was defined as >0 to 35 and >0 to 21 units/week and high levels of alcohol intake as >35 and >21 units/week. In total, there were 17,410 adults without prevalent cardiovascular diseases and complete data on alcohol and physical activity (43% men, median age 55 years). During a median follow-up period of 9.7 years, 2,204 adults (12.7%) died, 638 (3.7%) with CVM. Cox proportional-hazards models were adjusted for potential confounders such as marital status, social class, education, ethnicity, and longstanding illness. In the joint associations analysis, low activity combined with high levels of alcohol (CVM: hazard ratio [HR] 1.95, 95% confidence interval [CI] 1.28 to 2.96, p = 0.002; all-cause mortality: HR 1.64, 95% CI 1.32 to 2.03, p <0.001) and low activity combined with no alcohol (CVM: HR 1.93, 95% CI 1.35 to 2.76, p <0.001; all-cause mortality: HR 1.50, 95% CI 1.24 to 1.81, p <0.001) were linked to the highest risk, compared with moderate drinking and higher levels of physical activity. Within each given alcohol group, low activity was linked to increased CVM risk (e.g., HR 1.48, 95% CI 1.08 to 2.03, p = 0.014, for the moderate drinking group), but in the presence of high physical activity, high alcohol intake was not linked to increased CVM

  18. Torque Measurement of 3-DOF Haptic Master Operated by Controllable Electrorheological Fluid

    NASA Astrophysics Data System (ADS)

    Oh, Jong-Seok; Choi, Seung-Bok; Lee, Yang-Sub

    2015-02-01

    This work presents a torque measurement method of 3-degree-of-freedom (3-DOF) haptic master featuring controllable electrorheological (ER) fluid. In order to reflect the sense of an organ for a surgeon, the ER haptic master which can generate the repulsive torque of an organ is utilized as a remote controller for a surgery robot. Since accurate representation of organ feeling is essential for the success of the robot-assisted surgery, it is indispensable to develop a proper torque measurement method of 3-DOF ER haptic master. After describing the structural configuration of the haptic master, the torque models of ER spherical joint are mathematically derived based on the Bingham model of ER fluid. A new type of haptic device which has pitching, rolling, and yawing motions is then designed and manufactured using a spherical joint mechanism. Subsequently, the field-dependent parameters of the Bingham model are identified and generating repulsive torque according to applied electric field is measured. In addition, in order to verify the effectiveness of the proposed torque model, a comparative work between simulated and measured torques is undertaken.

  19. Relationship between electromyographic activity and clinically assessed rigidity studied at the wrist joint in Parkinson's disease.

    PubMed

    Meara, R J; Cody, F W

    1992-08-01

    The electromyographic (EMG) patterns recorded from wrist muscles during manually applied, repetitive flexion and extension movements of the wrist joint, used for simultaneous clinical assessment of rigidity, were studied in patients with Parkinson's disease and healthy subjects. Recordings were made whilst patients/subjects attempted voluntarily to relax the muscle of the arm whose wrist joint was manipulated. Individual patients were investigated before and at varying times after their routine daily medication as their clinical rigidity underwent associated modulations. It was often possible to induce additional alterations in clinical rigidity by instructing patients to perform an activation or Jendrassik-like manoeuvre (clenching the contralateral fist). In rigid patients, the approximately sinusoidal wrist displacements (60 deg, 1-1.5 Hz) typically elicited pronounced, cyclic modulations of EMG activities in wrist flexors and extensors; increases in EMG activity were phase-locked to the respective periods of muscle stretch. Stretch-related EMG activity reduced or disappeared as rigidity was abolished by drug therapy. The EMG patterns of patients showing cogwheel rigidity featured discrete, phasic bursts superimposed upon more generalized stretch-related increases in activity. In healthy subjects, showing no clinical rigidity, the pronounced cyclic modulations of EMG activity characteristic of rigid patients were absent during similar manually applied wrist displacements. Quantitative EMG measurements for individual patients, made 'on' and 'off' medication and as their rigidity fluctuated, indicated that mild (grade 1) and moderate (grade 2) rigidity was consistently associated with increased stretch-related activity compared with non-rigid conditions. Pair-wise statistical analysis indicated such increases in EMG to be significant. Similarly, the ratios of EMG activities in the stretched versus released muscles were significantly greater for grades 1 and 2

  20. In-vitro and in-vivo imaging of MMP activity in cartilage and joint injury

    SciTech Connect

    Fukui, Tomoaki; Tenborg, Elizabeth; Yik, Jasper H.N.; Haudenschild, Dominik R.

    2015-05-08

    Non-destructive detection of cartilage-degrading activities represents an advance in osteoarthritis (OA) research, with implications in studies of OA pathogenesis, progression, and intervention strategies. Matrix metalloproteinases (MMPs) are principal cartilage degrading enzymes that contribute to OA pathogenesis. MMPSense750 is an in-vivo fluorimetric imaging probe with the potential to continuously and non-invasively trace real-time MMP activities, but its use in OA-related research has not been reported. Our objective is to detect and characterize the early degradation activities shortly after cartilage or joint injury with MMPSense750. We determined the appropriate concentration, assay time, and linear range using various concentrations of recombinant MMPs as standards. We then quantified MMP activity from cartilage explants subjected to either mechanical injury or inflammatory cytokine treatment in-vitro. Finally, we performed in-vivo MMP imaging of a mouse model of post-traumatic OA. Our in-vitro results showed that the optimal assay time was highly dependent on the MMP enzyme. In cartilage explant culture media, mechanical impact or cytokine treatment increased MMP activity. Injured knees of mice showed significantly higher fluorescent signal than uninjured knees. We conclude that MMPSense750 detects human MMP activities and can be used for in-vitro study with cartilage, as well as in-vivo studies of knee injury, and can offering real-time insight into the degradative processes that occurring within the joint before structural changes become evident radiographically. - Highlights: • MMPSense750 is near-infrared fluorescent probe which can detect MMP activity. • MMPSense750 can detect human MMP-3, -9, and -13. • The reaction kinetics with MMPSense750 were different for the three MMPs. • MMPSense750 can visualized real time MMP activity in mouse injured knees. • MMPSense750 is convenient tool to evaluate real-time MMP activity non-invasively.

  1. The leading joint hypothesis for spatial reaching arm motions.

    PubMed

    Ambike, Satyajit; Schmiedeler, James P

    2013-02-01

    The leading joint hypothesis (LJH), developed for planar arm reaching, proposes that the interaction torques experienced by the proximal joint are low compared to the corresponding muscle torques. The human central nervous system could potentially ignore these interaction torques at the proximal (leading) joint with little effect on the wrist trajectory, simplifying joint-level control. This paper investigates the extension of the LJH to spatial reaching. In spatial motion, a number of terms in the governing equation (Euler's angular momentum balance) that vanish for planar movements are non-trivial, so their contributions to the joint torque must be classified as net, interaction or muscle torque. This paper applies definitions from the literature to these torque components to establish a general classification for all terms in Euler's equation. This classification is equally applicable to planar and spatial motion. Additionally, a rationale for excluding gravity torques from the torque analysis is provided. Subjects performed point-to-point reaching movements between targets whose locations ensured that the wrist paths lay in various portions of the arm's spatial workspace. Movement kinematics were recorded using electromagnetic sensors located on the subject's arm segments and thorax. The arm was modeled as a three-link kinematic chain with idealized spherical and revolute joints at the shoulder and elbow. Joint torque components were computed using inverse dynamics. Most movements were 'shoulder-led' in that the interaction torque impulse was significantly lower than the muscle torque impulse for the shoulder, but not the elbow. For the few elbow-led movements, the interaction impulse at the elbow was low, while that at the shoulder was high, and these typically involved large elbow and small shoulder displacements. These results support the LJH and extend it to spatial reaching motion.

  2. The Research and Training Activities for the Joint Institute for Aeronautics and Acoustics

    NASA Technical Reports Server (NTRS)

    Cantwell, Brian

    1997-01-01

    This proposal requests continued support for the program of activities to be undertaken by the Ames-Stanford Joint Institute for Aeronautics and Acoustics during the one-year period October 1, 1997 to September 30, 1998. The emphasis in this program is on training and research in experimental and computational methods with application to aerodynamics, acoustics and the important interactions between them. The program comprises activities in active flow control, Large Eddy Simulation of jet noise, flap aerodynamics and acoustics, high lift modeling studies and luminescent paint applications. During the proposed period there will be a continued emphasis on the interaction between NASA Ames, Stanford University and Industry, particularly in connection with the noise and high lift activities. The program will be conducted within the general framework of the Memorandum of Understanding (1976) establishing the Institute, as updated in 1993. As outlined in the agreement, the purposes of the Institute include the following: (1) To conduct basic and applied research; (2) to promote joint endeavors between Center scientists and those in the academic community; (3) to provide training to graduate students in specialized areas of aeronautics and acoustics through participation in the research programs of the Institute; (4) to provide opportunities for Post-Doctoral Fellows to collaborate in research programs of the Institute; and (5) to disseminate information about important aeronautical topics and to enable scientists and engineers of the Center to stay abreast of new advances through symposia, seminars and publications.

  3. The Research and Training Activities for the Joint Institute for Aeronautics and Acoustics

    NASA Technical Reports Server (NTRS)

    Cantwell, Brian

    1996-01-01

    This proposal requests continued support for the program of activities to be undertaken by the Ames-Stanford Joint Institute for Aeronautics and Acoustics during the one-year period October 1, 1996 to September 30, 1997. The emphasis in this program is on training and research in experimental and computational methods with application to aerodynamics, acoustics and the important interactions between them. The program comprises activities in active flow control, Large Eddy Simulation of jet noise, flap aerodynamics and acoustics, high lift modeling studies and luminescent paint applications. During the proposed period there will be a continued emphasis on the interaction between NASA Ames, Stanford University and Industry, particularly in connection with the noise and high lift activities. The program will be conducted within the general framework of the Memorandum of Understanding (1976) establishing the Institute, as updated in 1993. As outlined in the agreement, the purposes of the institute include the following: To conduct basic and applied research. To promote joint endeavors between Center scientists and those in the academic community To provide training to graduate students in specialized areas of aeronautics and acoustics through participation in the research programs of the Institute. To provide opportunities for Post-Doctoral Fellows to collaborate in research programs of the Institute. To disseminate information about important aeronautical topics and to enable scientists and engineers of the Center to stay abreast of new advances through symposia, seminars and publications.

  4. Split torque transmission load sharing

    NASA Technical Reports Server (NTRS)

    Krantz, T. L.; Rashidi, M.; Kish, J. G.

    1992-01-01

    Split torque transmissions are attractive alternatives to conventional planetary designs for helicopter transmissions. The split torque designs can offer lighter weight and fewer parts but have not been used extensively for lack of experience, especially with obtaining proper load sharing. Two split torque designs that use different load sharing methods have been studied. Precise indexing and alignment of the geartrain to produce acceptable load sharing has been demonstrated. An elastomeric torque splitter that has large torsional compliance and damping produces even better load sharing while reducing dynamic transmission error and noise. However, the elastomeric torque splitter as now configured is not capable over the full range of operating conditions of a fielded system. A thrust balancing load sharing device was evaluated. Friction forces that oppose the motion of the balance mechanism are significant. A static analysis suggests increasing the helix angle of the input pinion of the thrust balancing design. Also, dynamic analysis of this design predicts good load sharing and significant torsional response to accumulative pitch errors of the gears.

  5. Impact of decline-board squat exercises and knee joint angles on the muscle activity of the lower limbs.

    PubMed

    Lee, Daehee; Lee, Sangyong; Park, Jungseo

    2015-08-01

    [Purpose] This study aims to investigate how squat exercises on a decline board and how the knee joint angles affect the muscle activity of the lower limbs. [Subjects] The subjects were 26 normal adults. [Methods] A Tumble Forms wedge device was used as the decline board, and the knee joint angles were measured with a goniometer. To examine the muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior of the lower limbs, a comparison analysis with electromyography was conducted. [Results] The muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior increased with increased knee joint angles, both for squat exercises on the decline board and on a flat floor. When the knee joint angle was 45°, 60°, and 90°, the muscle activity of the rectus femoris was significantly higher and that of the tibialis anterior was significantly lower during squat exercises on the decline board than on the flat floor. When the knee joint angle was 90°, the muscle activity of the gastrocnemius lateralis was significantly lower. [Conclusion] Squat exercises on a decline board are an effective intervention to increase the muscle activity of the rectus femoris with increased knee joint angles.

  6. Ruminant methane reduction through livestock development in Tanzania. Final report for US Department of Energy and US Initiative on Joint Implementation--Activities Implemented Jointly

    SciTech Connect

    Livingston, Roderick

    1999-07-01

    This project was designed to help develop the US Initiative on Joint Implementation activities in Eastern Africa. It has been communicated in meetings with representatives from the Ministry of Environment of Tanzania and the consultant group that developed Tanzania's National Climate Change Action Plan, the Centre for Energy, Environment, Science and Technology, that this project fits very well with the developmental and environmental goals of the Government of Tanzania. The goal of the Activities Implemented Jointly ruminant livestock project is to reduce ruminant methane emissions in Eastern Africa. The project plans a sustainable cattle multiplication unit (CMU) at Mabuki Ranch in the Mwanza Region of Tanzania. This CMU will focus on raising genetically improved animals to be purchased by farmers, developmental organizations, and other CMUs in Tanzania. Through the purchase of these animals farmers will raise their income generation potential and reduce ruminant methane emissions.

  7. Physical Activity and Associations With Computed Tomography-Detected Lumbar Zygapophyseal Joint Osteoarthritis

    PubMed Central

    Suri, Pradeep; Hunter, David J.; Boyko, Edward J.; Rainville, James; Guermazi, Ali; Katz, Jeffrey N.

    2014-01-01

    Background Context There are no prior epidemiologic studies examining associations between physical activity and imaging-detected lumbar zygapophyseal joint osteoarthritis (ZJO) in a community-based sample. Purpose To determine whether physical activity is associated with prevalent lumbar ZJO on computed tomography (CT). Study Design/Setting Community-based cross-sectional study. Patient Sample 424 older adults from the Framingham Heart Study. Outcome Measures Participants received standardized CT assessments of lumbar ZJO at the L2-S1 levels. Severe lumbar ZJO was defined according to the presence and/or degree of joint space narrowing, osteophytosis, articular process hypertrophy, articular erosions, subchondral cysts, and intraarticular vacuum phenomenon. This definition of lumbar ZJO was based entirely on CT imaging findings, and did not include any clinical criteria such as low back pain. Methods Physical activity was measured using the Physical Activity Index, which estimates hours per day typically spent in these activity categories: sleeping, sitting, slight activity, moderate activity, or heavy activity. Participants reported on usual frequency of walking, running, swimming, and weightlifting. We used multivariable logistic regression to examine associations between self-reported activity and severe lumbar ZJO, while adjusting for key covariates including age, sex, height, and weight. Study funding was from NIH-K12HD01097. There were no study-specific conflicts of interest-associated biases. Results In multivariable analyses, ordinal categories of heavy physical activity duration per day were significantly associated with severe lumbar ZJO (p for trend=0.04), with the greatest risk observed for the category ≥ 3 hours/day (odds ratio [OR] 2.13 (95% confidence interval [CI]): 0.97–4.67). When heavy activity was modeled as a continuous independent variable, each hour was independently associated with 1.19 times the odds of severe lumbar ZJO (95% CI 1.03

  8. High torque miniature rotary actuator

    NASA Astrophysics Data System (ADS)

    Nalbandian, Ruben

    2005-07-01

    This paper summarizes the design and the development of a miniature rotary actuator (36 mm diameter by 100 mm length) used in spacecraft mechanisms requiring high torques and/or ultra-fine step resolution. This actuator lends itself to applications requiring high torque but with strict volume limitations which challenge the use of conventional rotary actuators. The design challenge was to develop a lightweight (less than 500 grams), very compact, high bandwidth, low power, thermally stable rotary actuator capable of producing torques in excess of 50 N.m and step resolutions as fine as 0.003 degrees. To achieve a relatively high torsional stiffness in excess of 1000 Nm/radian, the design utilizes a combination of harmonic drive and multistage planetary gearing. The unique design feature of this actuator that contributes to its light weight and extremely precise motion capability is a redundant stepper motor driving the output through a multistage reducing gearbox. The rotary actuator is powered by a high reliability space-rated stepper motor designed and constructed by Moog, Inc. The motor is a three-phase stepper motor of 15 degree step angle, producing twenty-four full steps per revolution. Since micro-stepping is not used in the design, and un-powered holding torque is exhibited at every commanded step, the rotary actuator is capable of reacting to torques as high as 35 Nm by holding position with the power off. The output is driven through a gear transmission having a total train ratio of 5120:1, resulting in a resolution of 0.003 degrees output rotation per motor step. The modular design of the multi-stage output transmission makes possible the addition of designs having different output parameters, such as lower torque and higher output speed capability. Some examples of an actuator family based on this growth capability will be presented in the paper.

  9. Some new evidence on human joint lubrication.

    PubMed Central

    Unsworth, A; Dowson, D; Wright, V

    1975-01-01

    Theoretical consideration has been given to the use of pendulum machines which are used to examine the frictional properties of human joints by incorporating them as fulcra. As a result, a new type of pendulum machine has been built which incorporates the facility to apply sudden loads to the joint on starting the swinging motion, and also the ability to measure directly the frictional torque experienced by the joint. The results obtained from natural hip joints indicate the presence of squeeze film lubrication under conditions of sudden loading of a joint. In addition, a self-generated fluid film process was observed at low loads while at higher loads boundary lubrication appeared to be important. These results have been used to describe the lubrication regimens occurring in a normal activity such as walking. A single experiment carried out on a hip from a patient suffering from severe rheumatoid arthritis has also been reported and the frictional resistance was seen to be increased fifteenfold compared to a normal hip. Images PMID:1190847

  10. The fatigue effect of a simulated futsal match protocol on isokinetic knee torque production.

    PubMed

    Dal Pupo, Juliano; Detanico, Daniele; Santos, Saray Giovana Dos

    2014-11-01

    The objective of this study was to investigate the effects of a simulated futsal match protocol on isokinetic knee torque production. Twenty-one young futsal players participated in this study and performed a futsal-specific protocol comprising two blocks of 20-minute activities to simulate the match demands. At pre-protocol, half-time, and post-protocol, the concentric and eccentric isokinetic peak torque of the knee flexor and extensor muscles, the angle of peak torque, and the conventional and functional torque ratios were assessed. ANOVA was used to compare the variables (significance level p <  0.05). A decrease of knee flexor and extensor eccentric torque and knee flexor concentric torque was found, in which the pre-protocol levels were higher than those at half-time, with both being larger than those at post-protocol. The knee extensor concentric torque reduced at half-time. The angle of eccentric torque of knee flexors increased, and the conventional and functional torque ratios decreased at post-protocol. In conclusion, the protocol produced a time-dependent reduction of knee flexor and extensor torque in both concentric and eccentric actions. These findings suggested a possible impairment of performance and the emergence of risk factors for hamstring strains during a futsal match.

  11. A cable-driven wrist robotic rehabilitator using a novel torque-field controller for human motion training

    NASA Astrophysics Data System (ADS)

    Chen, Weihai; Cui, Xiang; Zhang, Jianbin; Wang, Jianhua

    2015-06-01

    Rehabilitation technologies have great potentials in assisted motion training for stroke patients. Considering that wrist motion plays an important role in arm dexterous manipulation of activities of daily living, this paper focuses on developing a cable-driven wrist robotic rehabilitator (CDWRR) for motion training or assistance to subjects with motor disabilities. The CDWRR utilizes the wrist skeletal joints and arm segments as the supporting structure and takes advantage of cable-driven parallel design to build the system, which brings the properties of flexibility, low-cost, and low-weight. The controller of the CDWRR is designed typically based on a virtual torque-field, which is to plan "assist-as-needed" torques for the spherical motion of wrist responding to the orientation deviation in wrist motion training. The torque-field controller can be customized to different levels of rehabilitation training requirements by tuning the field parameters. Additionally, a rapidly convergent parameter self-identification algorithm is developed to obtain the uncertain parameters automatically for the floating wearable structure of the CDWRR. Finally, experiments on a healthy subject are carried out to demonstrate the performance of the controller and the feasibility of the CDWRR on wrist motion training or assistance.

  12. Tuberculosis of the manubriosternal joint and concurrent asymptomatic active pulmonary tuberculosis in a patient presenting with a chest wall mass.

    PubMed

    Gorospe, Luis; Ayala-Carbonero, Ana María; Rodríguez-Díaz, Ricardo; García Latorre, Raquel; Muñoz-Molina, Gemma María; Cabañero-Sánchez, Alberto

    2015-01-01

    A 62-year-old woman presented to our hospital with an anterior chest wall swelling. Computed tomography (CT) and magnetic resonance imaging showed findings consistent with an infectious arthritis of the manubriosternal joint, and CT images also demonstrated multiple centrilobular nodules in both lungs, suggesting an infectious bronchiolitis. A CT-guided fine needle aspiration of a presternal mass yielded growth of Mycobacterium tuberculosis. Bronchoalveolar lavage confirmed an active pulmonary tuberculosis. Septic arthritis of the manubriosternal joint is exceedingly rare.

  13. Differentiation between non-neural and neural contributors to ankle joint stiffness in cerebral palsy

    PubMed Central

    2013-01-01

    Background Spastic paresis in cerebral palsy (CP) is characterized by increased joint stiffness that may be of neural origin, i.e. improper muscle activation caused by e.g. hyperreflexia or non-neural origin, i.e. altered tissue viscoelastic properties (clinically: “spasticity” vs. “contracture”). Differentiation between these components is hard to achieve by common manual tests. We applied an assessment instrument to obtain quantitative measures of neural and non-neural contributions to ankle joint stiffness in CP. Methods Twenty-three adolescents with CP and eleven healthy subjects were seated with their foot fixated to an electrically powered single axis footplate. Passive ramp-and-hold rotations were applied over full ankle range of motion (RoM) at low and high velocities. Subject specific tissue stiffness, viscosity and reflexive torque were estimated from ankle angle, torque and triceps surae EMG activity using a neuromuscular model. Results In CP, triceps surae reflexive torque was on average 5.7 times larger (p = .002) and tissue stiffness 2.1 times larger (p = .018) compared to controls. High tissue stiffness was associated with reduced RoM (p < .001). Ratio between neural and non-neural contributors varied substantially within adolescents with CP. Significant associations of SPAT (spasticity test) score with both tissue stiffness and reflexive torque show agreement with clinical phenotype. Conclusions Using an instrumented and model based approach, increased joint stiffness in CP could be mainly attributed to higher reflexive torque compared to control subjects. Ratios between contributors varied substantially within adolescents with CP. Quantitative differentiation of neural and non-neural stiffness contributors in CP allows for assessment of individual patient characteristics and tailoring of therapy. PMID:23880287

  14. Large Torque Variations in Two Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    Woods, Peter M.; Kouveliotou, Chryssa; Gogus, Ersin; Finger, Mark H.; Swank, Jean; Markwardt, Craig B.; Hurley, Kevin; vanderKlis, Michiel

    2002-01-01

    We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-Ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor of approximately 4, which persist for several months. Using long-baseline phase-connected timing solutions as well as the overall frequency histories, we construct torque noise power spectra for each SGR (Soft Gamma Repeater). The power spectrum of each source is very red (power-law slope is approximately -3.5). The torque noise power levels are consistent with some accreting systems on timescales of approximately 1 yr, yet the full power spectrum is much steeper in frequency than any known accreting source. To the best of our knowledge, torque noise power spectra with a comparably steep frequency dependence have been seen only in young, glitching radio pulsars (e.g., Vela). The observed changes in spin-down rate do not correlate with burst activity; therefore, the physical mechanisms behind each phenomenon are also likely unrelated. Within the context of the magnetar model, seismic activity can not account for both the bursts and the long-term torque changes unless the seismically active regions are decoupled from one another.

  15. Atypical brain activation patterns during a face-to-face joint attention game in adults with autism spectrum disorder.

    PubMed

    Redcay, Elizabeth; Dodell-Feder, David; Mavros, Penelope L; Kleiner, Mario; Pearrow, Mark J; Triantafyllou, Christina; Gabrieli, John D; Saxe, Rebecca

    2013-10-01

    Joint attention behaviors include initiating one's own and responding to another's bid for joint attention to an object, person, or topic. Joint attention abilities in autism are pervasively atypical, correlate with development of language and social abilities, and discriminate children with autism from other developmental disorders. Despite the importance of these behaviors, the neural correlates of joint attention in individuals with autism remain unclear. This paucity of data is likely due to the inherent challenge of acquiring data during a real-time social interaction. We used a novel experimental set-up in which participants engaged with an experimenter in an interactive face-to-face joint attention game during fMRI data acquisition. Both initiating and responding to joint attention behaviors were examined as well as a solo attention (SA) control condition. Participants included adults with autism spectrum disorder (ASD) (n = 13), a mean age- and sex-matched neurotypical group (n = 14), and a separate group of neurotypical adults (n = 22). Significant differences were found between groups within social-cognitive brain regions, including dorsal medial prefrontal cortex (dMPFC) and right posterior superior temporal sulcus (pSTS), during the RJA as compared to SA conditions. Region-of-interest analyses revealed a lack of signal differentiation between joint attention and control conditions within left pSTS and dMPFC in individuals with ASD. Within the pSTS, this lack of differentiation was characterized by reduced activation during joint attention and relative hyper-activation during SA. These findings suggest a possible failure of developmental neural specialization within the STS and dMPFC to joint attention in ASD.

  16. Catecholamine secretion and adrenal nerve activity in response to movements of normal and inflamed knee joints in cats.

    PubMed Central

    Sato, A; Sato, Y; Schmidt, R F

    1986-01-01

    The effects of articular stimulation on adrenal catecholamine secretion and adrenal sympathetic nerve activity were studied using halothane anaesthetized cats. Various natural passive movements were applied to the normal and inflamed knee joints. Rhythmic flexions and extensions as well as rhythmic inward and outward rotation of normal knee joints within their physiological range of motion did not change nerve activity or the secretion of adrenal catecholamines. Static outward rotation in the normal working range was also ineffective. However, as soon as this static rotation was extended into the noxious range, significant increases in both of these variables were elicited. In the acutely inflamed knee joint, various passive movements produced increases in both adrenal sympathetic and catecholamine secretion. Especially noteworthy was the finding that movements of the inflamed knee joint that were within the normal range of motion produced increases in all variables. Articularly induced increases in adrenal sympathetic nerve activity were diminished by severing various hind-limb somatic afferent nerves and abolished by complete denervation of the knee joint. Additionally, section of the adrenal sympathetic nerves eliminated the catecholamine secretion response. From these data it was concluded that the responses observed in these experiments were reflexes having an afferent limb in hind-limb nerves and an efferent limb in the adrenal sympathetic nerves. A contribution of supraspinal structures was suggested for the reflex responses of sympatho-adrenal medullary function evoked by knee joint stimulations, since spinal transection at the C2 level completely abolished the responses. PMID:3795070

  17. Monitoring of bolted joints using piezoelectric active-sensing for aerospace applications

    SciTech Connect

    Park, Gyuhae; Farrar, Charles R; Park, Chan - Yik; Jun, Seung - Moon

    2010-01-01

    This paper is a report of an initial investigation into tracking and monitoring the integrity of bolted joints using piezoelectric active-sensors. The target application of this study is a fitting lug assembly of unmanned aerial vehicles (UAVs), where a composite wing is mounted to a UAV fuselage. The SHM methods deployed in this study are impedance-based SHM techniques, time-series analysis, and high-frequency response functions measured by piezoelectric active-sensors. Different types of simulated damage are introduced into the structure, and the capability of each technique is examined and compared. Additional considerations encountered in this initial investigation are made to guide further thorough research required for the successful field deployment of this technology.

  18. Peripheral and spinal activation of cannabinoid receptors by joint mobilization alleviates postoperative pain in mice.

    PubMed

    Martins, D F; Mazzardo-Martins, L; Cidral-Filho, F J; Gadotti, V M; Santos, A R S

    2013-01-01

    The present study was undertaken to investigate the relative contribution of cannabinoid receptors (CBRs) subtypes and to analyze cannabimimetic mechanisms involved in the inhibition of anandamide (AEA) and 2-arachidonoyl glycerol degradation on the antihyperalgesic effect of ankle joint mobilization (AJM). Mice (25-35g) were subjected to plantar incision (PI) and 24h after surgery animals received the following treatments, AJM for 9min, AEA (10mg/kg, intraperitoneal [i.p.]), WIN 55,212-2 (1.5mg/kg, i.p.), URB937 (0.01-1mg/kg, i.p.; a fatty acid amide hydrolase [FAAH] inhibitor) or JZL184 (0.016-16mg/kg, i.p.; a monoacylglycerol lipase [MAGL] inhibitor). Withdrawal frequency to mechanical stimuli was assessed 24h after PI and at different time intervals after treatments. Receptor specificity was investigated using selective CB1R (AM281) and CB2R (AM630) antagonists. In addition, the effect of the FAAH and MAGL inhibitors on the antihyperalgesic action of AJM was investigated. AJM, AEA, WIN 55,212-2, URB937 and JZL184 decreased mechanical hyperalgesia induced by PI. The antihyperalgesic effect of AJM was reversed by pretreatment with AM281 given by intraperitoneal and intrathecal routes, but not intraplantarly. Additionally, intraperitoneal and intraplantar, but not intrathecal administration of AM630 blocked AJM-induced antihyperalgesia. Interestingly, in mice pretreated with FAAH or the MAGL inhibitor the antihyperalgesic effect of AJM was significantly longer. This article presents data addressing the CBR mechanisms underlying the antihyperalgesic activity of joint mobilization as well as of the endocannabinoid catabolic enzyme inhibitors in the mouse postoperative pain model. Joint mobilization and these enzymes offer potential targets to treat postoperative pain.

  19. The mechanical and tribological properties of UHMWPE loaded ALN after mechanical activation for joint replacements.

    PubMed

    Gong, Kemeng; Qu, Shuxin; Liu, Yumei; Wang, Jing; Zhang, Yongchao; Jiang, Chongxi; Shen, Ru

    2016-08-01

    Ultra-high molecular weight polyethylene (UHMWPE) loaded with alendronate sodium (ALN) has tremendous potential as an orthopeadic biomaterial for joint replacements. However, poor mechanical and tribological properties of UHMWPE-ALN are still obstacle for further application. The purpose of this study was to investigate the effect and mechanism of mechanical activation on mechanical and tribological properties of 1wt% ALN-loaded UHMWPE (UHMWPE-ALN-ma). In this study, tensile test, small punch test and reciprocating sliding wear test were applied to characterize the mechanical and tribological properties of UHMWPE-ALN-ma. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) were employed to characterize UHMWPE-ALN-ma. Tensile test and small punch test showed that Young׳s modulus, tensile strength and work-to-failure (WTF) of UHMWPE-ALN-ma increased significantly compared to those of UHMWPE-ALN. The friction coefficients and wear factors of UHMWPE-ALN-ma both decreased significantly compared to those of UHMWPE-ALN. Mechanical activation obviously reduced type 1 (void) and type 2 (the disconnected and dislocated machining marks) fusion defects of UHMWPE-ALN-ma, which were revealed by SEM images of freeze fracture surfaces after etching and lateral surfaces of specimens after extension to fracture, respectively. It was attributed to peeled-off layers and chain scission of molecular chains of UHMWPE particles after mechanical activation, which were revealed by SEM images and FTIR spectra of UHMWPE-ALN-ma and UHMWPE-ALN, respectively. Moreover, EDS spectra revealed the more homogeneous distribution of ALN in UHMWPE-ALN-ma compared to that of UHMWPE-ALN. The present results showed that mechanical activation was a potential strategy to improve mechanical and tribological properties of UHMWPE-ALN-ma as an orthopeadic biomaterial for joint replacements.

  20. Effect of isotonic and isokinetic exercise on muscle activity and balance of the ankle joint

    PubMed Central

    Kim, Mi-Kyoung; Yoo, Kyung-Tae

    2015-01-01

    [Purpose] This study was performed to examine how the balance of lower limbs and the muscle activities of the tibialis anterior (TA), the medial gastrocnemius (GCM), and the peroneus longus (PL) are influenced by isotonic and isokinetic exercise of the ankle joint. [Subjects] The subjects of this study were healthy adults (n=20), and they were divided into two groups (isotonic=10, isokinetic=10). [Methods] Isotonic group performed 3 sets of 10 contractions at 50% of MVIC and Isokinetic group performed 3 sets of 60°/sec. Muscle activity was measured by EMG and balance was measured by one-leg standing test. [Results] For muscle activity, a main effect of group was found in the non-dominant TA, and the dominant TA, GCM and PL. For balance, a main effect of time was found in both groups for the sway area measured support was provided by the non-dominant side. [Conclusion] In terms of muscle activity, the two groups showed a significant difference, and the isokinetic group showed higher muscle activities. In terms of balance, there was a significant difference between the pre-test and the post-test. The results of this study may help in the selection of exercises for physical therapy, because they show that muscle activity and balance vary according to the type of exercise. PMID:25729181

  1. 14 CFR 29.361 - Engine torque.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine torque. 29.361 Section 29.361... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.361 Engine torque. The limit engine torque may not be less than the following: (a) For turbine engines, the highest of— (1)...

  2. 14 CFR 29.361 - Engine torque.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Engine torque. 29.361 Section 29.361... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.361 Engine torque. The limit engine torque may not be less than the following: (a) For turbine engines, the highest of— (1)...

  3. 14 CFR 29.361 - Engine torque.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Engine torque. 29.361 Section 29.361... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.361 Engine torque. The limit engine torque may not be less than the following: (a) For turbine engines, the highest of— (1)...

  4. 14 CFR 29.361 - Engine torque.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine torque. 29.361 Section 29.361... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.361 Engine torque. The limit engine torque may not be less than the following: (a) For turbine engines, the highest of— (1)...

  5. 14 CFR 29.361 - Engine torque.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine torque. 29.361 Section 29.361... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.361 Engine torque. The limit engine torque may not be less than the following: (a) For turbine engines, the highest of— (1)...

  6. Computerized Torque Control for Large dc Motors

    NASA Technical Reports Server (NTRS)

    Willett, Richard M.; Carroll, Michael J.; Geiger, Ronald V.

    1987-01-01

    Speed and torque ranges in generator mode extended. System of shunt resistors, electronic switches, and pulse-width modulation controls torque exerted by large, three-phase, electronically commutated dc motor. Particularly useful for motor operating in generator mode because it extends operating range to low torque and high speed.

  7. Knee joint laxity and neuromuscular characteristics of male and female soccer and basketball players.

    PubMed

    Rozzi, S L; Lephart, S M; Gear, W S; Fu, F H

    1999-01-01

    Anterior cruciate ligament injuries are occurring at a higher rate in female athletes compared with their male counterparts. Research in the area of anterior cruciate ligament injury has increasingly focused on the role of joint proprioception and muscle activity in promoting knee joint stability. We measured knee joint laxity, joint kinesthesia, lower extremity balance, the amount of time required to generate peak torque of the knee flexor and extensor musculature, and electromyographically assessed muscle activity in 34 healthy, collegiate-level athletes (average age, 19.6 +/- 1.5 years) who played soccer or basketball or both. Independent t-tests were used to determine significant sex differences. Results revealed that women inherently possess significantly greater knee joint laxity values, demonstrate a significantly longer time to detect the knee joint motion moving into extension, possess significantly superior single-legged balance ability, and produce significantly greater electromyographic peak amplitude and area of the lateral hamstring muscle subsequent to landing a jump. The excessive joint laxity of women appears to contribute to diminished joint proprioception, rendering the knee less sensitive to potentially damaging forces and possibly at risk for injury. Unable to rely on ligamentous structures, healthy female athletes appear to have adopted compensatory mechanisms of increased hamstring activity to achieve functional joint stabilization.

  8. Validity of trunk extensor and flexor torque measurements using isokinetic dynamometry.

    PubMed

    Guilhem, Gaël; Giroux, Caroline; Couturier, Antoine; Maffiuletti, Nicola A

    2014-12-01

    This study aimed to evaluate the validity and test-retest reliability of trunk muscle strength testing performed with a latest-generation isokinetic dynamometer. Eccentric, isometric, and concentric peak torque of the trunk flexor and extensor muscles was measured in 15 healthy subjects. Muscle cross sectional area (CSA) and surface electromyographic (EMG) activity were respectively correlated to peak torque and submaximal isometric torque for erector spinae and rectus abdominis muscles. Reliability of peak torque measurements was determined during test and retest sessions. Significant correlations were consistently observed between muscle CSA and peak torque for all contraction types (r=0.74-0.85; P<0.001) and between EMG activity and submaximal isometric torque (r ⩾ 0.99; P<0.05), for both extensor and flexor muscles. Intraclass correlation coefficients were comprised between 0.87 and 0.95, and standard errors of measurement were lower than 9% for all contraction modes. The mean difference in peak torque between test and retest ranged from -3.7% to 3.7% with no significant mean directional bias. Overall, our findings establish the validity of torque measurements using the tested trunk module. Also considering the excellent test-retest reliability of peak torque measurements, we conclude that this latest-generation isokinetic dynamometer could be used with confidence to evaluate trunk muscle function for clinical or athletic purposes.

  9. A structurally decoupled mechanism for measuring wrist torque in three degrees of freedom.

    PubMed

    Pan, Lizhi; Yang, Zhen; Zhang, Dingguo

    2015-10-01

    The wrist joint is a critical part of the human body for movement. Measuring the torque of the wrist with three degrees of freedom (DOFs) is important in some fields, including rehabilitation, biomechanics, ergonomics, and human-machine interfacing. However, the particular structure of the wrist joint makes it difficult to measure the torque in all three directions simultaneously. This work develops a structurally decoupled instrument for measuring and improving the measurement accuracy of 3-DOF wrist torque during isometric contraction. Three single-axis torque sensors were embedded in a customized mechanical structure. The dimensions and components of the instrument were designed based on requirement of manufacturability. A prototype of the instrument was machined, assembled, integrated, and tested. The results show that the structurally decoupled mechanism is feasible for acquiring wrist torque data in three directions either independently or simultaneously. As a case study, we use the device to measure wrist torques concurrently with electromyography signal acquisition in preparation for simultaneous and proportional myoelectric control of prostheses.

  10. A structurally decoupled mechanism for measuring wrist torque in three degrees of freedom

    NASA Astrophysics Data System (ADS)

    Pan, Lizhi; Yang, Zhen; Zhang, Dingguo

    2015-10-01

    The wrist joint is a critical part of the human body for movement. Measuring the torque of the wrist with three degrees of freedom (DOFs) is important in some fields, including rehabilitation, biomechanics, ergonomics, and human-machine interfacing. However, the particular structure of the wrist joint makes it difficult to measure the torque in all three directions simultaneously. This work develops a structurally decoupled instrument for measuring and improving the measurement accuracy of 3-DOF wrist torque during isometric contraction. Three single-axis torque sensors were embedded in a customized mechanical structure. The dimensions and components of the instrument were designed based on requirement of manufacturability. A prototype of the instrument was machined, assembled, integrated, and tested. The results show that the structurally decoupled mechanism is feasible for acquiring wrist torque data in three directions either independently or simultaneously. As a case study, we use the device to measure wrist torques concurrently with electromyography signal acquisition in preparation for simultaneous and proportional myoelectric control of prostheses.

  11. Joint Spacelab-J (SL-J) Activities at the Huntsville Operations Support Center (HOSC) Spacelab

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The science laboratory, Spacelab-J (SL-J), flown aboard the STS-47 flight was a joint venture between NASA and the National Space Development Agency of Japan (NASDA) utilizing a manned Spacelab module. The mission conducted 24 materials science and 20 life science experiments, of which 35 were sponsored by NASDA, 7 by NASA, and two collaborative efforts. Materials science investigations covered such fields as biotechnology, electronic materials, fluid dynamics and transport phenomena, glasses and ceramics, metals and alloys, and acceleration measurements. Life sciences included experiments on human health, cell separation and biology, developmental biology, animal and human physiology and behavior, space radiation, and biological rhythms. Test subjects included the crew, Japanese koi fish (carp), cultured animal and plant cells, chicken embryos, fruit flies, fungi and plant seeds, and frogs and frog eggs. Featured together in joint ground activities during the SL-J mission are NASA/NASDA personnel at the Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at Marshall Space Flight Center (MSFC).

  12. Temporal expectation and attention jointly modulate auditory oscillatory activity in the beta band.

    PubMed

    Todorovic, Ana; Schoffelen, Jan-Mathijs; van Ede, Freek; Maris, Eric; de Lange, Floris P

    2015-01-01

    The neural response to a stimulus is influenced by endogenous factors such as expectation and attention. Current research suggests that expectation and attention exert their effects in opposite directions, where expectation decreases neural activity in sensory areas, while attention increases it. However, expectation and attention are usually studied either in isolation or confounded with each other. A recent study suggests that expectation and attention may act jointly on sensory processing, by increasing the neural response to expected events when they are attended, but decreasing it when they are unattended. Here we test this hypothesis in an auditory temporal cueing paradigm using magnetoencephalography in humans. In our study participants attended to, or away from, tones that could arrive at expected or unexpected moments. We found a decrease in auditory beta band synchrony to expected (versus unexpected) tones if they were unattended, but no difference if they were attended. Modulations in beta power were already evident prior to the expected onset times of the tones. These findings suggest that expectation and attention jointly modulate sensory processing.

  13. The Joint Society of Nephrology in Germany, Switzerland and Austria - Five Decades of Successful Activities.

    PubMed

    Heidland, August; Ritz, Eberhard; Lang, Florian

    2016-02-01

    The joint Society of Nephrology in Germany, Switzerland and Austria was founded on April 10th, 1961 in Wiesbaden. Board members were Hans Sarre, Kurt Kramer, Klaus Rother, Francois Reubi, Bruno Watschinger, Wolfgang Dutz, Ernst Wollheim and Karl Ullrich. The mission of the society was an intensive interaction between basic science of the kidney (anatomy, physiology, pathophysiology, biochemistry and molecular biology) and clinical research in nephrology and hypertension. Every year scientific symposia took place in different venues in one of the three countries, except in the years between 1963-1987, when the congresses of the International Society of Nephrology took place. Practical issues of clinical nephrology, in particular renal replacement therapy (dialysis and transplantation), were covered since 1971 by a specific Working Group. In 1994 the Advisory Board (Kuratorium) of the Society of Nephrology was founded as a result of an initiative of Peter Weidmann (Bern). Its main goals were Update Seminars in Nephrology and Hypertensionin Eastern Europe, in part together with the Joint Action of Nephrology and an Eastern European ScholarshipProgram. Despite the prosperous work of this European society within nearly five decades in Germany a national society was founded as well, which combined all activities of nephrology in one organization. The German Society of Nephrology was founded in 2009.

  14. Residual force enhancement during multi-joint leg extensions at joint- angle configurations close to natural human motion.

    PubMed

    Paternoster, Florian Kurt; Seiberl, Wolfgang; Hahn, Daniel; Schwirtz, Ansgar

    2016-03-21

    The isometric steady-state forces following lengthening are greater than those produced at the same muscle length and activation level but without prior lengthening. Although residual force enhancement (RFE) has been investigated across a range of conditions, its relevance for daily human movement is still poorly understood. We aimed to study RFE in a setup imitating daily activity, i.e., submaximal activation of the lower extremity's muscles with slightly flexed knee joints comparable to human walking. A motor-driven leg press dynamometer was used for randomly arranged purely isometric and isometric-eccentric-isometric contractions. Thirteen subjects performed multi-joint leg extensions, which were feedback-controlled at 30% of maximum voluntary vastus lateralis activation. Isometric-eccentric-isometric contractions incorporated a stretch from 30° to 50° knee flexion, while isometric contractions were performed at 50° knee flexion. Isometric contractions following stretch and purely isometric reference contractions were performed at 50° knee flexion. Kinematics, forces, and muscular activity were measured using 3D optical motion tracking, force plates, and surface EMG of 9 lower limb muscles of the right leg and joint torques were calculated by inverse dynamics. Variables of standardization (EMG, joint angles) showed no differences between contraction conditions. Eight of 13 subjects showed RFE of up to 24.8±32.5% for external forces and joint torques. Because the remaining 5 non-responders failed to produce enhanced forces during the stretch, we believe that RFE is functionally relevant for muscle function comparable to everyday human motion but only if there is enhanced force during stretch that sufficiently triggers mechanisms underlying RFE.

  15. Joint maximum likelihood estimation of activation and Hemodynamic Response Function for fMRI.

    PubMed

    Bazargani, Negar; Nosratinia, Aria

    2014-07-01

    Blood Oxygen Level Dependent (BOLD) functional magnetic resonance imaging (fMRI) maps the brain activity by measuring blood oxygenation level, which is related to brain activity via a temporal impulse response function known as the Hemodynamic Response Function (HRF). The HRF varies from subject to subject and within areas of the brain, therefore a knowledge of HRF is necessary for accurately computing voxel activations. Conversely a knowledge of active voxels is highly beneficial for estimating the HRF. This work presents a joint maximum likelihood estimation of HRF and activation based on low-rank matrix approximations operating on regions of interest (ROI). Since each ROI has limited data, a smoothing constraint on the HRF is employed via Tikhonov regularization. The method is analyzed under both white noise and colored noise. Experiments with synthetic data show that accurate estimation of the HRF is possible with this method without prior assumptions on the exact shape of the HRF. Further experiments involving real fMRI experiments with auditory stimuli are used to validate the proposed method.

  16. Activation of PAR2 receptors sensitizes primary afferents and causes leukocyte rolling and adherence in the rat knee joint

    PubMed Central

    Russell, FA; Schuelert, N; Veldhoen, VE; Hollenberg, MD; McDougall, JJ

    2012-01-01

    Background and Purpose The PAR2 receptors are involved in chronic arthritis by mechanisms that are as yet unclear. Here, we examined PAR2 activation in the rat knee joint. Experimental Approach PAR2 in rat knee joint dorsal root ganglia (DRG) cells at L3-L5, retrogradely labelled with Fluoro-gold (FG) were demonstrated immunohistochemically. Electrophysiological recordings from knee joint nerve fibres in urethane anaesthetized Wistar rats assessed the effects of stimulating joint PAR2 with its activating peptide, 2-furoyl-LIGRLO-NH2 (1–100 nmol·100 μL−1, via close intra-arterial injection). Fibre firing rate was recorded during joint rotations before and 15 min after administration of PAR2 activating peptide or control peptide. Leukocyte kinetics in the synovial vasculature upon PAR2 activation were followed by intravital microscopy for 60 min after perfusion of 2-furoyl-LIGRLO-NH2 or control peptide. Roles for transient receptor potential vanilloid-1 (TRPV1) or neurokinin-1 (NK1) receptors in the PAR2 responses were assessed using the selective antagonists, SB366791 and RP67580 respectively. Key Results PAR2 were expressed in 59 ± 5% of FG-positive DRG cells; 100 nmol 2-furoyl-LIGRLO-NH2 increased joint fibre firing rate during normal and noxious rotation, maximal at 3 min (normal; 110 ± 43%, noxious; 90 ± 31%). 2-Furoyl-LIGRLO-NH2 also significantly increased leukocyte rolling and adhesion over 60 min. All these effects were blocked by pre-treatment with SB366791 and RP67580 (P < 0.05 compared with 2-furoyl-LIGRLO-NH2 alone). Conclusions and Implications PAR2 receptors play an acute inflammatory role in the knee joint via TRPV1- and NK1-dependent mechanisms involving both PAR2-mediated neuronal sensitization and leukocyte trafficking. PMID:22849826

  17. A Method for and Issues Associated with the Determination of Space Suit Joint Requirements

    NASA Technical Reports Server (NTRS)

    Matty, Jennifer E.; Aitchison, Lindsay

    2010-01-01

    This joint mobility KC lecture included information from two papers, "A Method for and Issues Associated with the Determination of Space Suit Joint Requirements" and "Results and Analysis from Space Suit Joint Torque Testing," as presented for the International Conference on Environmental Systems in 2009 and 2010, respectively. The first paper discusses historical joint torque testing methodologies and approaches that were tested in 2008 and 2009. The second paper discusses the testing that was completed in 2009 and 2010.

  18. Fracture toughness of low activation ferritic steel (JLF-1) weld joint at room temperature

    NASA Astrophysics Data System (ADS)

    Nishimura, A.; Inoue, N.; Muroga, T.

    1998-10-01

    A low activation ferritic steel has been developed for a candidate of a structural material of nuclear fusion reactors. Since welding must be performed when the support structures are constructed, fracture toughness of the weld joint has to be characterized as well as the base metal in an engineering sense. In this report, 25 mm thick plates of JLF-1, which contains 9% Cr and 2% W, are butt-welded by a tungsten inert gas (TIG) procedure, and the fracture toughness of the base plate and the weld metal is investigated at room temperature using 1T and 0.5T CT specimens. The base metal reveals high fracture toughness of about 430 kJ/m 2. However, the weld metal showed unstable big pop-ins. One sample fractured in a nearly elastic condition and another sample showed a toughness of over 400 kJ/m 2.

  19. The Influence of Task Complexity on Knee Joint Kinetics Following ACL Reconstruction

    PubMed Central

    Schroeder, Megan J.; Krishnan, Chandramouli; Dhaher, Yasin Y.

    2015-01-01

    Background Previous research indicates that subjects with anterior cruciate ligament reconstruction exhibit abnormal knee joint movement patterns during functional activities like walking. While the sagittal plane mechanics have been studied extensively, less is known about the secondary planes, specifically with regard to more demanding tasks. This study explored the influence of task complexity on functional joint mechanics in the context of graft-specific surgeries. Methods In 25 participants (10 hamstring tendon graft, 6 patellar tendon graft, 9 matched controls), three-dimensional joint torques were calculated using a standard inverse dynamics approach during level walking and stair descent. The stair descent task was separated into two functionally different sub-tasks—step-to-floor and step-to-step. The differences in external knee moment profiles were compared between groups; paired differences between the reconstructed and non-reconstructed knees were also assessed. Findings The reconstructed knees, irrespective of graft type, typically exhibited significantly lower peak knee flexion moments compared to control knees during stair descent, with the differences more pronounced in the step-to-step task. Frontal plane adduction torque deficits were graft-specific and limited to the hamstring tendon knees during the step-to-step task. Internal rotation torque deficits were also primarily limited to the hamstring tendon graft group during stair descent. Collectively, these results suggest that task complexity was a primary driver of differences in joint mechanics between anterior cruciate ligament reconstructed individuals and controls, and such differences were more pronounced in individuals with hamstring tendon grafts. Interpretation The mechanical environment experienced in the cartilage during repetitive, cyclical tasks such as walking and other activities of daily living has been argued to contribute to the development of degenerative changes to the joint

  20. Torque expression in self-ligating orthodontic brackets and conventionally ligated brackets: A systematic review

    PubMed Central

    Al-Thomali, Yousef; Mohamed, Roshan-Noor; Basha, Sakeenabi

    2017-01-01

    Background To evaluate the torque expression of self ligating (SL) orthodontic brackets and conventionally ligated brackets and the torque expression in active and passive SL brackets. Material and Methods Our systematic search included MEDLINE, EMBASE, CINAHL, PsychINFO, Scopus, and key journals and review articles; the date of the last search was April 4th 2016. We graded the methodological quality of the studies by means of the Quality Assessment Tool for Quantitative Studies, developed for the Effective Public Health Practice Project (EPHPP). Results In total, 87 studies were identified for screening, and 9 studies were eligible. The quality assessment rated one of the study as being of strong quality, 7 (77.78%) of these studies as being of moderate quality. Three out of 7 studies which compared SL and conventionally ligated brackets showed, conventionally ligated brackets with highest torque expression compared to SL brackets. Badawi showed active SL brackets with highest torque expression compared to passive SL brackets. Major and Brauchli showed no significant differences in torque expression of active and passive SL brackets. Conclusions Conventionally ligated brackets presented with highest torque expression compared to SL brackets. Minor difference was recorded in a torque expression of active and passive SL brackets. Key words:Systematic review, self ligation, torque expression, conventional ligation. PMID:28149476

  1. Low-Torque Seal Development

    NASA Technical Reports Server (NTRS)

    Lattime, Scott B.; Borowski, Richard

    2009-01-01

    The EcoTurn Class K production prototypes have passed all AAR qualification tests and received conditional approval. The accelerated life test on the second set of seals is in progress. Due to the performance of the first set, no problems are expected.The seal has demonstrated superior performance over the HDL seal in the test lab with virtually zero torque and excellent contamination exclusion and grease retention.

  2. Torque and Twist against Superlubricity

    NASA Astrophysics Data System (ADS)

    Filippov, Alexander E.; Dienwiebel, Martin; Frenken, Joost W. M.; Klafter, Joseph; Urbakh, Michael

    2008-02-01

    Superlubricity between incommensurate surfaces provides a desired low-friction state essential for the function of small-scale machines. Here we demonstrate experimentally and theoretically that superlubricity in contacts lubricated by lamellar solids might be eliminated due to torque-induced reorientation coupled to lateral motion. We find that the possibility of reorientation always leads to stabilization of a high frictional state which corresponds to a commensurate configuration.

  3. Torque and twist against superlubricity.

    PubMed

    Filippov, Alexander E; Dienwiebel, Martin; Frenken, Joost W M; Klafter, Joseph; Urbakh, Michael

    2008-02-01

    Superlubricity between incommensurate surfaces provides a desired low-friction state essential for the function of small-scale machines. Here we demonstrate experimentally and theoretically that superlubricity in contacts lubricated by lamellar solids might be eliminated due to torque-induced reorientation coupled to lateral motion. We find that the possibility of reorientation always leads to stabilization of a high frictional state which corresponds to a commensurate configuration.

  4. Estimation of Electrically-Evoked Knee Torque from Mechanomyography Using Support Vector Regression

    PubMed Central

    Ibitoye, Morufu Olusola; Hamzaid, Nur Azah; Abdul Wahab, Ahmad Khairi; Hasnan, Nazirah; Olatunji, Sunday Olusanya; Davis, Glen M.

    2016-01-01

    The difficulty of real-time muscle force or joint torque estimation during neuromuscular electrical stimulation (NMES) in physical therapy and exercise science has motivated recent research interest in torque estimation from other muscle characteristics. This study investigated the accuracy of a computational intelligence technique for estimating NMES-evoked knee extension torque based on the Mechanomyographic signals (MMG) of contracting muscles that were recorded from eight healthy males. Simulation of the knee torque was modelled via Support Vector Regression (SVR) due to its good generalization ability in related fields. Inputs to the proposed model were MMG amplitude characteristics, the level of electrical stimulation or contraction intensity, and knee angle. Gaussian kernel function, as well as its optimal parameters were identified with the best performance measure and were applied as the SVR kernel function to build an effective knee torque estimation model. To train and test the model, the data were partitioned into training (70%) and testing (30%) subsets, respectively. The SVR estimation accuracy, based on the coefficient of determination (R2) between the actual and the estimated torque values was up to 94% and 89% during the training and testing cases, with root mean square errors (RMSE) of 9.48 and 12.95, respectively. The knee torque estimations obtained using SVR modelling agreed well with the experimental data from an isokinetic dynamometer. These findings support the realization of a closed-loop NMES system for functional tasks using MMG as the feedback signal source and an SVR algorithm for joint torque estimation. PMID:27447638

  5. Biological activity and migration of wear particles in the knee joint: an in vivo comparison of six different polyethylene materials.

    PubMed

    Utzschneider, S; Lorber, V; Dedic, M; Paulus, A C; Schröder, C; Gottschalk, O; Schmitt-Sody, M; Jansson, V

    2014-06-01

    Wear of polyethylene causes loosening of joint prostheses because of the particle mediated activity of the host tissue. It was hypothesized that conventional and crosslinked polyethylene particles lead to similar biological effects around the knee joint in vivo as well as to a similar particle distribution in the surrounding tissues. To verify these hypotheses, particle suspensions of six different polyethylene materials were injected into knee joints of Balb/C mice and intravital microscopic, histological and immunohistochemical evaluations were done after 1 week. Whereas the biological effects on the synovial layer and the subchondral bone of femur and tibia were similar for all the polyethylenes, two crosslinked materials showed an elevated cytokine expression in the articular cartilage. Furthermore, the distribution of particles around the joint was dependent on the injected polyethylene material. Those crosslinked particles, which remained mainly in the joint space, showed an increased expression of TNF-alpha in articular cartilage. The data of this study support the use of crosslinked polyethylene in total knee arthroplasty. In contrast, the presence of certain crosslinked wear particles in the joint space can lead to an elevated inflammatory reaction in the remaining cartilage, which challenges the potential use of those crosslinked polyethylenes for unicondylar knee prostheses.

  6. New Torque Estimation Method Considering Spatial Harmonics and Torque Ripple Reduction in Permanent Magnet Synchronous Motors

    NASA Astrophysics Data System (ADS)

    Hida, Hajime; Tomigashi, Yoshio; Ueyama, Kenji; Inoue, Yukinori; Morimoto, Shigeo

    This paper proposes a new torque estimation method that takes into account the spatial harmonics of permanent magnet synchronous motors and that is capable of real-time estimation. First, the torque estimation equation of the proposed method is derived. In the method, the torque ripple of a motor can be estimated from the average of the torque calculated by the conventional method (cross product of the fluxlinkage and motor current) and the torque calculated from the electric input power to the motor. Next, the effectiveness of the proposed method is verified by simulations in which two kinds of motors with different components of torque ripple are considered. The simulation results show that the proposed method estimates the torque ripple more accurately than the conventional method. Further, the effectiveness of the proposed method is verified by performing on experiment. It is shown that the torque ripple is decreased by using the proposed method to the torque control.

  7. Braking due to non-resonant magnetic perturbations and comparison with neoclassical toroidal viscosity torque in EXTRAP T2R

    NASA Astrophysics Data System (ADS)

    Frassinetti, L.; Sun, Y.; Fridström, R.; Menmuir, S.; Olofsson, K. E. J.; Brunsell, P. R.; Khan, M. W. M.; Liang, Y.; Drake, J. R.

    2015-09-01

    The non-resonant magnetic perturbation (MP) braking is studied in the EXTRAP T2R reversed-field pinch (RFP) and the experimental braking torque is compared with the torque expected by the neoclassical toroidal viscosity (NTV) theory. The EXTRAP T2R active coils can apply magnetic perturbations with a single harmonic, either resonant or non-resonant. The non-resonant MP produces velocity braking with an experimental torque that affects a large part of the core region. The experimental torque is clearly related to the plasma displacement, consistent with a quadratic dependence as expected by the NTV theory. The work show a good qualitative agreement between the experimental torque in a RFP machine and NTV torque concerning both the torque density radial profile and the dependence on the non-resonant MP harmonic.

  8. Paroxetine alleviates T lymphocyte activation and infiltration to joints of collagen-induced arthritis

    PubMed Central

    Wang, Qingtong; Wang, Longsheng; Wu, Li; Zhang, Mei; Hu, Shanshan; Wang, Rui; Han, Yongsheng; Wu, Yujing; Zhang, Lingling; Wang, Xinming; Sun, Wuyi; Wei, Wei

    2017-01-01

    T cell infiltration to synovial tissue is an early pathogenic mechanism of rheumatoid arthritis (RA). In the present work, we reveal that G protein coupled receptor kinase 2 (GRK2) is abundantly expressed in T cells of collagen-induced arthritis (CIA). A GRK2 inhibitor, paroxetine protects the joints from inflammation and destruction, primarily through inhibition of both CD4+ helper T (Th) cell and CD8+ cytotoxic T (Tc) cell migration to synovial tissue. Meanwhile, paroxetine restores the balance of Th/Tc, effector Th (Theff)/ naïve Th (Thnaive) and effector Tc (Tceff)/ naïve Tc (Tcnaive) to equilibrium by elevating the frequency of Thnaive, Tcnaive and regulatory Th cells; reducing the increased Theff, activated Th and Tceff, having a similar effect as methotrexate (MTX). In addition, both serum and synovial IL-1β, TNF-α and CX3CL1 expression was effectively inhibited in treated rats. In vitro assay confirmed that paroxetine inhibits CX3CL1-induced T cell migration through blocking the activity of GRK2. Among three MAPK families, paroxetine was found to be able to decrease the phosphorylation of ERK. This study elucidates that paroxetine attenuates the symptoms of CIA rats due to its inhibitory effect on T cell activation and infiltration to synovial tissue via suppression of ERK pathway. PMID:28349925

  9. Effects of Series Elasticity on the Human Knee Extension Torque-Angle Relationship in Vivo

    ERIC Educational Resources Information Center

    Kubo, Keitaro; Ohgo, Kazuya; Takeishi, Ryuichi; Yoshinaga, Kazunari; Tsunoda, Naoya; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2006-01-01

    The purpose of this study was to investigate the effects of series elasticity on the torque-angle relationship of the knee extensors in vivo. Forty-two men volunteered to take part in the present study. The participants performed maximal voluntary isometric contractions at eight knee-joint angles (40, 50, 60, 70, 80, 90, 100, 110[degree]). The…

  10. Torque magnetometry in unconventional superconductors

    NASA Astrophysics Data System (ADS)

    Li, Lu

    This thesis describes torque magnetometry studies on unconventional superconductors. Torque magnetometry measures the anisotropic magnetization of samples by recording their torque signals in a tilted magnetic field. Applied to superconductors, this method provides a reliable way to measure the field dependence of magnetization with high resolution under extreme conditions: DC magnetic fields from zero to 45.2 T, and temperature from 300 mK to 300K. The results can be used to determine many important parameters, such as the upper critical field H c2, the superconducting condensation energy, the onset temperature of diamagnetic signals, and so on. We carried out the torque magnetometry measurements on unconventional superconductors---high Tc superconductors and the p-wave superconductor Sr2RuO4---and uncovered new features that do not exist in conventional BCS superconductors. In high Tc superconductors, our torque magnetometry studies focus on the properties of the vortex liquid state. First, by comparing the observed magnetization curves with the Nernst effect results in Bi 2Sr2CaCu2O8+delta, we confirm that the unusually large Nernst effect signals originate from the surviving vortex liquid state above Tc. Second, the M-H curves near the critical temperature Tc suggest that the nature of the transition is the Kosterlitz-Thouless transition. Near Tc, the magnetization response at low field is strongly nonlinear, and the T dependence of the magnetic susceptibility in the low-field limit approaches the predicted curve from the Kosterlitz-Thouless transition. Third, the measurements in intense magnetic field up to 45 T reveal the unusual, weak T-dependence of Hc2. These observations strongly support the existence of the vortex liquid state above Tc. The superconducting state is destroyed by the phase fluctuation of the pair condensate, while the pair condensate keeps its amplitude above T c. Further studies in single-layered high Tc superconductors reveal more

  11. The effects of elbow joint angle change on the elbow flexor muscle activation in pulley with weight exercise.

    PubMed

    Kang, Taewook; Seo, Youngjoon; Park, Jaehoon; Dong, Eunseok; Seo, Byungdo; Han, Dongwook

    2013-09-01

    [Purpose] This research investigated the effect of angular variation of flexion of the elbow joint on the muscle activation of elbow flexor muscles. [Subjects] The research subjects were 24 male college students with a dominant right hand who had no surgical or neurological disorders and gave their prior written consent to participation with full knowledge of the method and purpose of this study. [Methods] The subjects' shoulder joints stayed in the resting position, and the elbow joint was positioned at angles of 55°, 70°, and 90°. The angle between the pulley with weights and forearm stayed at 90°. Surface electromyography was used to measure muscle activities. Three measurements were made at each elbow angle, and every time the angle changed, two minutes rest was given. [Result] The muscle activities of the elbow flexors showed significant changes with change in the elbow joint angle, except for the biceps brachii activities between the angles of 55° and 70° of elbow flexion. The muscle activities of the biceps brachii and brachioradialis showed angle-related changes in the order of 55°, which showed the biggest value, followed by 70° and 90°. [Conclusion] In order to improve muscle strength of the elbow flexor using a pulley system, it seems more effective to have a 90° angle between the pulley with weights and the forearm when the muscle is stretched to a length 20% greater than its resting position.

  12. The Effects of Elbow Joint Angle Change on the Elbow Flexor Muscle Activation in Pulley with Weight Exercise

    PubMed Central

    Kang, Taewook; Seo, Youngjoon; Park, Jaehoon; Dong, Eunseok; Seo, Byungdo; Han, Dongwook

    2013-01-01

    [Purpose] This research investigated the effect of angular variation of flexion of the elbow joint on the muscle activation of elbow flexor muscles. [Subjects] The research subjects were 24 male college students with a dominant right hand who had no surgical or neurological disorders and gave their prior written consent to participation with full knowledge of the method and purpose of this study. [Methods] The subjects' shoulder joints stayed in the resting position, and the elbow joint was positioned at angles of 55°, 70°, and 90°. The angle between the pulley with weights and forearm stayed at 90°. Surface electromyography was used to measure muscle activities. Three measurements were made at each elbow angle, and every time the angle changed, two minutes rest was given. [Result] The muscle activities of the elbow flexors showed significant changes with change in the elbow joint angle, except for the biceps brachii activities between the angles of 55° and 70° of elbow flexion. The muscle activities of the biceps brachii and brachioradialis showed angle-related changes in the order of 55°, which showed the biggest value, followed by 70° and 90°. [Conclusion] In order to improve muscle strength of the elbow flexor using a pulley system, it seems more effective to have a 90° angle between the pulley with weights and the forearm when the muscle is stretched to a length 20% greater than its resting position. PMID:24259930

  13. Ankle Instability Effects on Joint Position Sense When Stepping Across the Active Movement Extent Discrimination Apparatus

    PubMed Central

    Witchalls, Jeremy; Waddington, Gordon; Blanch, Peter; Adams, Roger

    2012-01-01

    Context Individuals with and without functional ankle instability have been tested for deficits in lower limb proprioception with varied results. Objective To determine whether a new protocol for testing participants' joint position sense during stepping is reliable and can detect differences between participants with unstable and stable ankles. Design Descriptive laboratory study. Setting University clinical laboratory. Patients or Other Participants Sample of convenience involving 21 young adult university students and staff. Ankle stability was categorized by score on the Cumberland Ankle Instability Tool; 13 had functional ankle instability, 8 had healthy ankles. Intervention(s) Test-retest of ankle joint position sense when stepping onto and across the Active Movement Extent Discrimination Apparatus twice, separated by an interim test, standing still on the apparatus and moving only 1 ankle into inversion. Main Outcome Measure(s) Difference in scores between groups with stable and unstable ankles and between test repeats. Results Participants with unstable ankles were worse at differentiating between inversion angles underfoot in both testing protocols. On repeated testing with the stepping protocol, performance of the group with unstable ankles was improved (Cohen d = 1.06, P = .006), whereas scores in the stable ankle group did not change in the second test (Cohen d = 0.04, P = .899). Despite this improvement, the unstable group remained worse at differentiating inversion angles on the stepping retest (Cohen d = 0.99, P = .020). Conclusions The deficits on proprioceptive tests shown by individuals with functional ankle instability improved with repeated exposure to the test situation. The learning effect may be the result of systematic exposure to ankle-angle variation that led to movement-specific learning or increased confidence when stepping across the apparatus. PMID:23182010

  14. Spin-orbit torque opposing the Oersted torque in ultrathin Co/Pt bilayers

    SciTech Connect

    Skinner, T. D. Irvine, A. C.; Heiss, D.; Kurebayashi, H.; Ferguson, A. J.; Wang, M.; Hindmarch, A. T.; Rushforth, A. W.

    2014-02-10

    Current-induced torques in ultrathin Co/Pt bilayers were investigated using an electrically driven ferromagnetic resonance technique. The angle dependence of the resonances, detected by a rectification effect as a voltage, was analysed to determine the symmetries and relative magnitudes of the spin-orbit torques. Both anti-damping (Slonczewski) and field-like torques were observed. As the ferromagnet thickness was reduced from 3 to 1 nm, the sign of the sum of the field-like torque and Oersted torque reversed. This observation is consistent with the emergence of a Rashba spin orbit torque in ultra-thin bilayers.

  15. Joint swelling

    MedlinePlus

    Swelling of a joint ... Joint swelling may occur along with joint pain . The swelling may cause the joint to appear larger or abnormally shaped. Joint swelling can cause pain or stiffness. After an ...

  16. Joint positioning sense, perceived force level and two-point discrimination tests of young and active elderly adults

    PubMed Central

    Franco, Priscila G.; Santos, Karini B.; Rodacki, André L. F.

    2015-01-01

    Background: Changes in the proprioceptive system are associated with aging. Proprioception is important to maintaining and/or recovering balance and to reducing the risk of falls. Objective: To compare the performance of young and active elderly adults in three proprioceptive tests. Method: Twenty-one active elderly participants (66.9±5.5 years) and 21 healthy young participants (24.6±3.9 years) were evaluated in the following tests: perception of position of the ankle and hip joints, perceived force level of the ankle joint, and two-point discrimination of the sole of the foot. Results: No differences (p>0.05) were found between groups for the joint position and perceived force level. On the other hand, the elderly participants showed lower sensitivity in the two-point discrimination (higher threshold) when compared to the young participants (p < 0.01). Conclusion: Except for the cutaneous plantar sensitivity, the active elderly participants had maintained proprioception. Their physical activity status may explain similarities between groups for the joint position sense and perceived force level, however it may not be sufficient to prevent sensory degeneration with aging. PMID:26443978

  17. Association of joint occurrence of warm and dry conditions over Greece with anticyclonic activity during summer

    NASA Astrophysics Data System (ADS)

    Hatzaki, Maria; Nastos, Panagiotis; Polychroni, Iliana; Flocas, Helena A.; Kouroutzoglou, John; Dalezios, Nicolas R.

    2016-04-01

    Anticyclones are often associated with extreme phenomena, like prolonged droughts or heatwaves and, thus, they can significantly impact fauna and flora, water resources and public health. In this study, the association of the summer anticyclonic activity with the joint occurrence of extreme warm and dry conditions over Greece is explored. The warm and dry extreme conditions are defined by utilizing the Warm/Dry (WD) index for representative meteorological stations from sub-regions of Greece with different climatic features. The WD index is the number of days over a period (here summer) having at the same time mean air temperature > 75th percentile of daily mean temperature and precipitation < 25th percentile of daily precipitation amounts. The anticyclonic activity is determined by the density of the anticyclonic systems over the greater Mediterranean region, which, during summer, is maximized over the Balkans and the northern African coast. The anticyclonic system density has resulted from the comprehensive climatology of Mediterranean anticyclones that was assembled with the aid of the finding and tracking scheme of the University of Melbourne (MS scheme), using the ERA-Interim mean sea-level pressure fields for 1979-2012. The examination of inter-annual and spatial variations of the WD index in association with shifts of the anticyclonic maxima shows that the different sub-regions of Greece are not affected evenly, stressing the role of the complex topography of the region and the variations in the subtropical jet position.

  18. [Jointed estrogenic activities of bisphenol A and three of its analogs].

    PubMed

    Zhang, Hong-chang; Chen, Liang-yan; Liu, Shu-shen; Yin, Da-qiang

    2009-01-01

    The combined effect of environmental endocrine disruptors (EEDs) is one of the hottest topics. The estrogenic activities of BPA, BPAF, BPAP, BPF were tested based on recombinant gene yeast assay. Six mixtures were designed based on the result of the test,each of which had an equitoxic ratio ray (EC10 or EC50). The EC50 values are 6.81 x 10(-6) mol x L(-1), 7.44 x 10(-7) mol x L(-1), 1.43 x 10(-5) mol x L(-1), 7.52 x 10(-6) mol x L(-1) for BPA, BPAF, BPAP and BPF respectively,which reveals that the estrogenic activities order among the four bisphenols was BPAF> BPA> BPF> BPAP. The experiment shows that when BPA mixes with BPAF, BPAP and BPF in different ratios individually, different combination effects are produced. It reveals that the combined ratios of the components may affect the combined effect. The dose addition model and the independent action model are used to identify the combined effect. They are testified to be more intuitionistic and more comprehensive than other joint effect indices.

  19. Large Torque Variations in Two Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    Woods, Peter M.; Kouveliotou, Chryssa; Gogus, Ersin; Finger, Mark H.; Swank, Jean; Markwardt, Craig B.; Hurley, Kevin; vanderKlis, Michiel; Six, N. Frank (Technical Monitor)

    2001-01-01

    We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor of approximately 4, which persist for several months. Using long baseline phase-connected timing solutions as well as the overall frequency histories, we construct torque noise power spectra for each SGR. The power spectrum of each source is very red (power-law slope approximately -3.5). These power spectra are consistent in normalization with some accreting systems, yet much steeper in slope than any known accreting source. To the best of our knowledge, torque noise power spectra with a comparably steep frequency dependence have only been seen in young, glitching radio pulsars (e.g. Vela). The observed changes in spin-down rate do not correlate with burst activity, therefore, the physical mechanisms behind each phenomenon are also likely unrelated. Within the context of the magnetar model, seismic activity cannot account for both the bursts and the long-term torque changes unless the seismically active regions are decoupled from one another.

  20. Design of a knee joint mechanism that adapts to individual physiology.

    PubMed

    Jiun-Yih Kuan; Pasch, Kenneth A; Herr, Hugh M

    2014-01-01

    This paper describes the design of a new knee joint mechanism, called the Adaptive Coupling Joint (ACJ). The new mechanism has an adaptive trajectory of the center of rotations (COR) that automatically matches those of the attached biological joint. The detailed design is presented as well as characterization results of the ACJ. Conventional exoskeleton and assistive devices usually consider limb joints as a one to three degrees of freedom (DOFs) joint synthesized by multiple one-DOF hinge joints in a single plane. However, the biological joints are complex and usually rotate with respect to a changing COR. As a result, the mismatch between limb joint motion and mechanical interface motion can lead to forces that cause undesired ligament and muscle length changes and internal mechanical changes. These undesired changes contribute to discomfort, as well as to the slippage and sluggish interaction between humans and devices. It is shown that the ACJ can transmit planetary torques from either active or passive devices to the limbs without altering the normal biological joint motion.

  1. Active Metal Brazing and Characterization of Brazed Joints in Titanium to Carbon-Carbon Composites

    NASA Technical Reports Server (NTRS)

    Singh, M.; Shpargel, T. P.; Morscher, G. N.; Asthana, R.

    2006-01-01

    The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSiI. The joint microstructures were examined using optical microscopy and scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The results of the microstructure analysis indicate solute redistribution across the joint and possible metallurgical bond formation via interdiffusion, which led to good wetting and spreading. A tube-on-plate tensile test was used to evaluate joint strength of Ti-tube/ C-C composite joints. The load-carrying ability was greatest for the Cu-ABA braze joint structures. This system appeared to have the best braze spreading which resulted in a larger braze/C-C composite bonded area compared to the other two braze materials. Also, joint loadcarrying ability was found to be higher for joint structures where the fiber tows in the outer ply of the C-C composite were aligned perpendicular to the tube axis when compared to the case where fiber tows were aligned parallel to the tube axis.

  2. Joint Coordination and Muscle Activities of Ballet Dancers During Tiptoe Standing.

    PubMed

    Tanabe, Hiroko; Fujii, Keisuke; Kouzaki, Motoki

    2017-01-01

    We aimed to investigate joint coordination of lower limbs in dancers during tiptoe standing and the relationship between joint coordination and muscle coactivation. Seven female ballet dancers performed tiptoe standing with six leg positions (fi e classical dance positions and one modern dance position) for 10 s. The kinematic data of the metatarsophalangeal (MP), ankle, knee, and hip joints was collected, and surface electromyography (EMG) of over 13 lower limb muscles was conducted. Principal component analysis was performed to determine joint coordination. MP-ankle and ankle-knee had in-phase coordination, whereas knee-hip showed anti-phase coordination in the sagittal plane. In addition, most EMG-EMG coherence around the MP and ankle joints was significant up to 50 Hz when these two joints swayed with in-phase. This suggests that different joint coordination patterns are associated with neural processing related to different muscle coactivation patterns. In conclusion, ballet dancers showed in-phase coordination from the MP to knee joints, which was associated with muscle coactivation to a higher frequency domain (up to 50 Hz) in comparison with anti-phase coordination.

  3. Landau-Lifshitz theory of thermomagnonic torque

    NASA Astrophysics Data System (ADS)

    Kim, Se Kwon; Tserkovnyak, Yaroslav

    2015-07-01

    We derive the thermomagnonic torque associated with smooth magnetic textures subjected to a temperature gradient in the framework of the stochastic Landau-Lifshitz-Gilbert equation. Our approach captures on equal footing two distinct contributions: (i) a local entropic torque that is caused by a temperature dependence of the effective exchange field, the existence of which had been previously suggested based on numerics, and (ii) the well-known spin-transfer torque induced by thermally induced magnon flow. The dissipative components of two torques have the same structure, following a common phenomenology, but opposite signs, with the twice as large entropic torque leading to a domain-wall motion toward the hotter region. We compare the efficiency of the torque-driven domain-wall motion with the recently proposed Brownian thermophoresis.

  4. Lamb wave based active damage identification in adhesively bonded composite lap joints

    NASA Astrophysics Data System (ADS)

    Jolly, Prateek

    Bonding composite structures using adhesives offers several advantages over mechanical fastening such as better flow stress, weight saving, improved fatigue resistance and the ability to join dissimilar structures. The hesitation to adopt adhesively bonded composite joints stems from the lack of knowledge regarding damage initiation and propagation mechanisms within the joint. A means of overcoming this hesitation is to continuously monitor damage in the joint. This study proposes a methodology to conduct structural health monitoring (SHM) of an adhesively bonded composite lap joint using acoustic, guided Lamb waves by detecting, locating and predicting the size of damage. Finite element modeling of a joint in both 2D and 3D is used to test the feasibility of the proposed damage triangulation technique. Experimental validation of the methodology is conducted by detecting the presence, location and size of inflicted damage with the use of tuned guided Lamb waves.

  5. Observational facts regarding the joint activities of the southwest vortex and plateau vortex after its departure from the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Yu, Shuhua; Gao, Wenliang; Xiao, Dixiang; Peng, Jun

    2016-01-01

    Using atmospheric observational data from 1998 to 2013, station rainfall data, TRMM (Tropical Rainfall Measuring Mission) data, as well as annual statistics for the plateau vortex and shear line, the joint activity features of sustained departure plateau vortexes (SDPVs) and southwest vortexes (SWVs) are analyzed. Some new and useful observational facts and understanding are obtained about the joint activities of the two types of vortex. The results show that: (1) The joint active period of the two vortexes is from May to August, and mostly in June and July. (2) The SDPVs of the partnership mainly originate near Zaduo, while the SWVs come from Jiulong. (3) Most of the two vortexes move in almost the same direction, moving eastward together with the low trough. The SDPVs mainly act in the area to the north of the Yangtze River, while the SWVs are situated across the Yangtze River valley. (4) The joint activity of the two vortexes often produces sustained regional heavy rainfall to the south of the Yellow River, influencing wide areas of China, and even as far as the Korean Peninsula, Japan and Vietnam. (5) Most of the two vortexes are baroclinic or cold vortexes, and they both become strengthened in terms of their joint activity. (6) When the two vortexes move over the sea, their central pressure descends and their rainfall increases, especially for SWVs. (7) The two vortexes might spin over the same area simultaneously when there are tropical cyclones in the eastern and southern seas of China, or move southward together if a tropical cyclone appears near Hainan Island.

  6. Common Bolted Joint Analysis Tool

    NASA Technical Reports Server (NTRS)

    Imtiaz, Kauser

    2011-01-01

    Common Bolted Joint Analysis Tool (comBAT) is an Excel/VB-based bolted joint analysis/optimization program that lays out a systematic foundation for an inexperienced or seasoned analyst to determine fastener size, material, and assembly torque for a given design. Analysts are able to perform numerous what-if scenarios within minutes to arrive at an optimal solution. The program evaluates input design parameters, performs joint assembly checks, and steps through numerous calculations to arrive at several key margins of safety for each member in a joint. It also checks for joint gapping, provides fatigue calculations, and generates joint diagrams for a visual reference. Optimum fastener size and material, as well as correct torque, can then be provided. Analysis methodology, equations, and guidelines are provided throughout the solution sequence so that this program does not become a "black box:" for the analyst. There are built-in databases that reduce the legwork required by the analyst. Each step is clearly identified and results are provided in number format, as well as color-coded spelled-out words to draw user attention. The three key features of the software are robust technical content, innovative and user friendly I/O, and a large database. The program addresses every aspect of bolted joint analysis and proves to be an instructional tool at the same time. It saves analysis time, has intelligent messaging features, and catches operator errors in real time.

  7. Larger plantar flexion torque variability implies less stable balance in the young: an association affected by knee position.

    PubMed

    Mello, Emanuele Moraes; Magalhães, Fernando Henrique; Kohn, André Fabio

    2013-12-01

    The present study examined the association between plantar flexion torque variability during isolated isometric contractions and during quiet bipedal standing. For plantar flexion torque measurements in quiet stance (QS), subjects stood still over a force plate. The mean plantar flexion torque level exerted by each subject in QS (divided by 2 to give the torque due to a single leg) served as the target torque level for right leg force-matching tasks in extended knee (KE) and flexed knee (KF) conditions. Muscle activation levels (EMG amplitudes) of the triceps surae and mean, standard deviation and coefficient of variation of plantar flexion torque were computed from signals acquired during periods with and without visual feedback. No significant correlations were found between EMG amplitudes and torque variability, regardless of the condition and muscle being analyzed. A significant correlation was found between torque variability in QS and KE, whereas no significant correlation was found between torque variability in QS and KF, regardless of vision availability. Therefore, torque variability measured in a controlled extended knee plantar flexion contraction is a predictor of torque variability in the anterior-posterior direction when the subjects are in quiet standing. In other words, larger plantar flexion torque variability in KE (but not in KF) implies less stable balance. The mechanisms underlying the findings above are probably associated with the similar proprioceptive feedback from the triceps surae in QS and KE and poorer proprioceptive feedback from the triceps surae in KF due to the slackening of the gastrocnemii. An additional putative mechanism includes the different torque contributions of each component of the triceps surae in the two knee angles. From a clinical and research standpoint, it would be advantageous to be able to estimate changes in balance ability by means of simple measurements of torque variability in a force matching task.

  8. Design of a new torque standard machine based on a torque generation method using electromagnetic force

    NASA Astrophysics Data System (ADS)

    Nishino, Atsuhiro; Ueda, Kazunaga; Fujii, Kenichi

    2017-02-01

    To allow the application of torque standards in various industries, we have been developing torque standard machines based on a lever deadweight system, i.e. a torque generation method using gravity. However, this method is not suitable for expanding the low end of the torque range, because of the limitations to the sizes of the weights and moment arms. In this study, the working principle of the torque generation method using an electromagnetic force was investigated by referring to watt balance experiments used for the redefinition of the kilogram. Applying this principle to a rotating coordinate system, an electromagnetic force type torque standard machine was designed and prototyped. It was experimentally demonstrated that SI-traceable torque could be generated by converting electrical power to mechanical power. Thus, for the first time, SI-traceable torque was successfully realized using a method other than that based on the force of gravity.

  9. Torque converter and assembly utilizing same

    SciTech Connect

    Pitassi, V.E.; Fernandez, A.

    1989-12-26

    This patent describes a torque converter for converting a first torque to a second torque. It comprises: a housing; an input shaft having the first torque; a driving sun gear rotatable about a first axis, the input shaft being coupled to the sun gear; a driven carrier including a shaft portion rotatable about the first axis; a first planetary shaft mounted on the driven carrier coaxillay with a second axis parallel to the first axis; a first planetary gear meshing with and driven by the sun gear and mounted on the first planetary shaft so that the first planetary gear is rotatable about the second axis; a first mass eccentric to the second axis and coupled to the first planetary gear for rotation together about the second axis; first and second unidirectional clutches connected to the shaft portion of the driven carrier and operating in opposite directions; an output torque shaft, one if the first and second unidirectional clutches being coupled to the output torque shaft to transmit the second torque thereto in a pulsating fashion and to permit continuous rotation of the output torque shaft and the other one of the first and second unidirectional clutches being connected to the housing to transmit an algebraic addition of the first and second torques together.

  10. 40 CFR 1065.310 - Torque calibration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... range. Oscillate or rotate the dynamometer during calibration to reduce frictional static hysteresis... during calibration to reduce frictional static hysteresis. In this case, the reference torque...

  11. 40 CFR 1065.310 - Torque calibration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... range. Oscillate or rotate the dynamometer during calibration to reduce frictional static hysteresis... during calibration to reduce frictional static hysteresis. In this case, the reference torque...

  12. Torque limited drive for manual valves

    DOEpatents

    Elliott, Philip G.; Underwood, Daniel E.

    1989-06-06

    The present invention is directed to a torque-limiting handwheel device for preventing manual valves from being damaged due to the application of excessive torque during the opening or closing operation of the valves. Torque can only be applied when ridges in the handwheel assembly engage in channels machined in the face of the baseplate. The amount of torque required for disengagement of the ridges from the channels is determined by the force exerted by various Bellville springs and the inclination of the side faces of the channels.

  13. Torque limited drive for manual valves

    DOEpatents

    Elliott, Philip G.; Underwood, Daniel E.

    1989-01-01

    The present invention is directed to a torque-limiting handwheel device for preventing manual valves from being damaged due to the application of excessive torque during the opening or closing operation of the valves. Torque can only be applied when ridges in the handwheel assembly engage in channels machined in the face of the baseplate. The amount of torque required for disengagement of the ridges from the channels is determined by the force exerted by various Bellville springs and the inclination of the side faces of the channels.

  14. Knee and Hip Joint Kinematics Predict Quadriceps and Hamstrings Neuromuscular Activation Patterns in Drop Jump Landings

    PubMed Central

    Malfait, Bart; Dingenen, Bart; Smeets, Annemie; Staes, Filip; Pataky, Todd; Robinson, Mark A.; Vanrenterghem, Jos; Verschueren, Sabine

    2016-01-01

    Purpose The purpose was to assess if variation in sagittal plane landing kinematics is associated with variation in neuromuscular activation patterns of the quadriceps-hamstrings muscle groups during drop vertical jumps (DVJ). Methods Fifty female athletes performed three DVJ. The relationship between peak knee and hip flexion angles and the amplitude of four EMG vectors was investigated with trajectory-level canonical correlation analyses over the entire time period of the landing phase. EMG vectors consisted of the {vastus medialis(VM),vastus lateralis(VL)}, {vastus medialis(VM),hamstring medialis(HM)}, {hamstring medialis(HM),hamstring lateralis(HL)} and the {vastus lateralis(VL),hamstring lateralis(HL)}. To estimate the contribution of each individual muscle, linear regressions were also conducted using one-dimensional statistical parametric mapping. Results The peak knee flexion angle was significantly positively associated with the amplitudes of the {VM,HM} and {HM,HL} during the preparatory and initial contact phase and with the {VL,HL} vector during the peak loading phase (p<0.05). Small peak knee flexion angles were significantly associated with higher HM amplitudes during the preparatory and initial contact phase (p<0.001). The amplitudes of the {VM,VL} and {VL,HL} were significantly positively associated with the peak hip flexion angle during the peak loading phase (p<0.05). Small peak hip flexion angles were significantly associated with higher VL amplitudes during the peak loading phase (p = 0.001). Higher external knee abduction and flexion moments were found in participants landing with less flexed knee and hip joints (p<0.001). Conclusion This study demonstrated clear associations between neuromuscular activation patterns and landing kinematics in the sagittal plane during specific parts of the landing. These findings have indicated that an erect landing pattern, characterized by less hip and knee flexion, was significantly associated with an

  15. Observed frequency-independent torque in flagellar bacterial motors optimizes space exploration

    NASA Astrophysics Data System (ADS)

    Di Salvo, Mario E.; Condat, C. A.

    2012-12-01

    A surprising feature of many bacterial motors is the apparently conserved form of their torque-frequency relation. Experiments indicate that the torque provided by the bacterial rotary motor is approximately constant over a large range of angular speeds. This is observed in both monotrichous and peritrichous bacteria, independently of whether they are propelled by a proton flux or by a Na+ ion flux. If the relation between angular speed ω and swimming speed is linear, a ω-independent torque implies that the power spent in active motion is proportional to the instantaneous bacterial speed. Using realistic values of the relevant parameters, we show that a constant torque maximizes the volume of the region explored by a bacterium in a resource-depleted medium. Given that nutrients in the ocean are often concentrated in separate, ephemeral patches, we propose that the observed constancy of the torque may be a trait evolved to maximize bacterial survival in the ocean.

  16. Study on Transmission Torque Characteristics of a Surface-Permanent-Magnet-Type Magnetic Gear

    NASA Astrophysics Data System (ADS)

    Niguchi, Noboru; Hirata, Katsuhiro; Hayakawa, Yuichi

    Magnetic gears have some advantages such as low mechanical loss and maintenance-free operation that are not observed in conventional mechanical gears. In addition, magnetic gears have inherent overload protection. Therefore, magnetic gears are expected to be used in special applications; for example, they can be used in a joint of a humanoid robot. Recently, various types of new magnetic gears have been proposed. Among these new gears, a surface-permanent-magnet-type (SPM-type) magnetic gear employing harmonic magnetic flux has gained attention because of its high transmission torque density, though it has a complex structure with multipole magnets. Some studies on an SPM-type magnetic gear have been carried out, but there are few papers on cogging torque. This paper describes the transmission torque characteristics of an SPM-type magnetic gear. The operating principle and the transmission torque under synchronous operation are formulated in accordance with the gear ratio. High orders of the cogging torque are computed by employing the 3-D finite element method, and the validity of the analysis is verified by carrying out measurements on a prototype. Furthermore, a method for reducing the cogging torque is discussed.

  17. Report of activities of the IAU/IAG Joint Working Group on Theory of Earth rotation

    NASA Astrophysics Data System (ADS)

    Ferrandiz, Jose M.; Gross, Richard S.; Getino, Juan; Brzezinski, Aleksander; Heinkelmann, Robert

    2014-05-01

    Earth rotation has been considered as one of the three pillars of geodesy. In April 2013 the International Association of Geodesy (IAG) and the International Astronomical Union (IAU) set up a Joint WG on Theory of the Earth Rotation to promote the development of improved theories of Earth rotation meeting the needs of accuracy of the near future as recommended by, e.g. GGOS, the Global Geodetic Observing System of the IAG. That JWG is chaired by the first two authors. Its structure comprises three Sub-WGs addressing Precession/Nutation, Polar Motion and UT1 and Numerical Solutions and Validation, which are chaired by the last three authors, respectively. Those SWG should work in parallel, for the sake of efficiency, but keeping consistency as an overall issue. This presentation intends to report about the initial activities carried out by the JWG and the work under development. A main task is to catalogue and to go in depth into the potential sources of inconsistency, at the level of precision given by the measurements of the space geodetic techniques.

  18. Effect of peroxisome proliferator activated receptor (PPAR)gamma agonists on prostaglandins cascade in joint cells.

    PubMed

    Moulin, David; Poleni, Paul-Emile; Kirchmeyer, Mélanie; Sebillaud, Sylvie; Koufany, Meriem; Netter, Patrick; Terlain, Bernard; Bianchi, Arnaud; Jouzeau, Jean-Yves

    2006-01-01

    In response to inflammatory cytokines, chondrocytes and synovial fibroblasts produce high amounts of prostaglandins (PG) which self-perpetuate locally the inflammatory reaction. Prostaglandins act primarily through membrane receptors coupled to G proteins but also bind to nuclear Peroxisome Proliferator-Activated Receptors (PPARs). Amongst fatty acids, the cyclopentenone metabolite of PGD2, 15-deoxy-Delta12,14PGJ2 (15d-PGJ2), was shown to be a potent ligand of the PPARgamma isotype prone to inhibit the production of inflammatory mediators. As the stimulated synthesis of PGE2 originates from the preferential coupling of inducible enzymes, cyclooxygenase-2 (COX-2) and membrane PGE synthase-1 (mPGES-1), we investigated the potency of 15d-PGJ2 to regulate prostaglandins synthesis in rat chondrocytes stimulated with interleukin-1beta (IL-1beta). We demonstrated that 15d-PGJ2, but not the high-affinity PPARgamma ligand rosiglitazone, decreased almost completely PGE2 synthesis and mPGES-1 expression. The inhibitory potency of 15d-PGJ2 was unaffected by changes in PPARgamma expression and resulted from inhibition of NF-kappaB nuclear binding and IkappaBalpha sparing, secondary to reduced phosphorylation of IKKbeta. Consistently with 15d-PGJ2 being a putative endogenous regulator of the inflammatory reaction if synthesized in sufficient amounts, the present data confirm the variable PPARgamma-dependency of its effects in joint cells while underlining possible species and cell types specificities.

  19. High-torque quiet gear

    NASA Astrophysics Data System (ADS)

    Moody, Paul E.

    1995-07-01

    A high-torque quiet gear construction consists of an inner hub having a plurality of circumferentially spaced arms extending radially outwardly therefrom, and an outer ring member having a plurality of circumferentially spaced-teeth extending radially inwardly therefrom. The ring member further includes a plurality of gear formations on an outer surface thereof for intermeshing with other gears. The teeth of the ring member are received in spaced relation in corresponding spaces formed between adjacent arms of the hub. An elastomeric member is received in the space formed between the hub and the ring member to form a resilient correction between the arms of the hub and the teeth of the ring member. The side surfaces of the arms and the teeth extend generally parallel to each other and at least partially overlap in a longitudinal direction. The purpose of this configuration is to place the elastomeric member in compression when torque is applied to the hub. Since elastomeric material is relatively incompressible, the result is low shear loads on the adhesive bonds which hold the elastomeric member to both the hub and outer ring member.

  20. Joint mimicking mechanical load activates TGFβ1 in fibrin-poly(ester-urethane) scaffolds seeded with mesenchymal stem cells.

    PubMed

    Gardner, Oliver F W; Fahy, Niamh; Alini, Mauro; Stoddart, Martin J

    2016-07-22

    Transforming growth factor-β1 (TGF-β1) is widely used in an active recombinant form to stimulate the chondrogenic differentiation of mesenchymal stem cells (MSCs). Recently, it has been shown that the application of multiaxial load, that mimics the loading within diarthrodial joints, to MSCs seeded in to fibrin-poly(ester-urethane) scaffolds leads to the endogenous production and secretion of TGF-β1 by the mechanically stimulated cells, which in turn drives the chondrogenic differentiation of the cells within the scaffold. The work presented in this short communication provides further evidence that the application of joint mimicking multiaxial load induces the secretion of TGF-β1 by mechanically stimulated MSCs. The results of this work also show that joint-like multiaxial mechanical load activates latent TGF-β1 in response to loading in the presence or absence of cells; this activation was not seen in non-loaded control scaffolds. Despite the application of mechanical load to scaffolds with different distributions/numbers of cells no significant differences were seen in the percentage of active TGF-β1 quantified in the culture medium of scaffolds from different groups. The similar level of activation in scaffolds containing different numbers of cells, cells at different stages of differentiation or with different distributions of cells suggests that this activation results from the mechanical forces applied to the culture system rather than differences in cellular behaviour. These results are relevant when considering rehabilitation protocols after cell therapy or microfracture, for articular cartilage repair, where increased TGF-β1 activation in response to joint mobilization may improve the quality of developing cartilaginous repair material. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Activity vs. rest in the treatment of bone, soft tissue and joint injuries.

    PubMed Central

    Buckwalter, J. A.

    1995-01-01

    One of the most important advances in the treatment of musculoskeletal injuries has come from understanding that controlled early resumption of activity can promote restoration of function, and that treatment of injuries with prolonged rest may delay recovery and adversely affect normal tissues. In the last decade of the nineteenth century two widely respected orthopaedists with extensive clinical experience strongly advocated opposing treatments of musculoskeletal injuries. Hugh Owen Thomas in Liverpool believed that enforced, uninterrupted prolonged rest produced the best results. He noted that movement of injured tissues increased inflammation, and that, "It would indeed be as reasonable to attempt to cure a fever patient by kicking him out of bed, as to benefit joint disease by a wriggling at the articulation." Just Lucas-Championnier in Paris took the opposite position. He argued that early controlled active motion accelerated restoration of function, although he noted that mobility had to be given in limited doses. In general, Thomas' views met with greater acceptance in the early part of this century, but experimental studies of the last several decades generally support Lucas-Championneir. They confirm and help explain the deleterious effects of prolonged rest and the beneficial effects of activity on the musculoskeletal tissues. They have shown that maintenance of normal bone, tendon and ligament, articular cartilage and muscle structure and composition require repetitive use, and that changes in the patterns of tissue loading can strengthen or weaken normal tissues. Although all the musculoskeletal tissues can respond to repetitive loading, they vary in the magnitude and type of response to specific patterns of activity. Furthermore, their responsiveness may decline with increasing age. Skeletal muscle and bone demonstrate the most apparent response to changes in activity in individuals of any age. Cartilage and dense fibrous tissues also can respond to

  2. 77 FR 74279 - Agency Information Collection (VA/DOD Joint Disability Evaluation Board Claim): Activity under...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-13

    ... President Bush's Interagency Task Force on Returning Global War on Terror Heroes, VA and the Department of Defense (DOD) have agreed to develop a joint process in which Global War on Terror (GWOT) service...

  3. 77 FR 60746 - Proposed Information Collection (VA/DOD Joint Disability Evaluation Board Claim) Activity...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-04

    ... Interagency Task Force on Returning Global War on Terror Heroes, VA and the Department of Defense (DOD) have agreed to develop a joint process in which Global War on Terror (GWOT) service members are evaluated...

  4. Insertion torque, resonance frequency, and removal torque analysis of microimplants.

    PubMed

    Tseng, Yu-Chuan; Ting, Chun-Chan; Du, Je-Kang; Chen, Chun-Ming; Wu, Ju-Hui; Chen, Hong-Sen

    2016-09-01

    This study aimed to compare the insertion torque (IT), resonance frequency (RF), and removal torque (RT) among three microimplant brands. Thirty microimplants of the three brands were used as follows: Type A (titanium alloy, 1.5-mm × 8-mm), Type B (stainless steel, 1.5-mm × 8-mm), and Type C (titanium alloy, 1.5-mm × 9-mm). A synthetic bone with a 2-mm cortical bone and bone marrow was used. Each microimplant was inserted into the synthetic bone, without predrilling, to a 7 mm depth. The IT, RF, and RT were measured in both vertical and horizontal directions. One-way analysis of variance and Spearman's rank correlation coefficient tests were used for intergroup and intragroup comparisons, respectively. In the vertical test, the ITs of Type C (7.8 Ncm) and Type B (7.5 Ncm) were significantly higher than that of Type A (4.4 Ncm). The RFs of Type C (11.5 kHz) and Type A (10.2 kHz) were significantly higher than that of Type B (7.5 kHz). Type C (7.4 Ncm) and Type B (7.3 Ncm) had significantly higher RTs than did Type A (4.1 Ncm). In the horizontal test, both the ITs and RTs were significantly higher for Type C, compared with Type A. No significant differences were found among the groups, and the study hypothesis was accepted. Type A had the lowest inner/outer diameter ratio and widest apical facing angle, engendering the lowest IT and highest RF values. However, no significant correlations in the IT, RF, and RT were observed among the three groups.

  5. Rheumatoid factor measured by fluoroimmunoassay: a responsive measure of rheumatoid arthritis disease activity that is associated with joint damage

    PubMed Central

    Knijff-Dutmer, E; Drossaers-Bakker, W; Verhoeven, A; van der Sluijs, Ve... G; Boers, M; van der Linden, S; van de Laar, M

    2002-01-01

    Objectives: To determine whether rheumatoid factors (RFs), measured as continuous variables by time resolved fluoroimmunoassay, reflect disease activity in rheumatoid arthritis (RA). Further, to study the association of RFs and other disease activity parameters with radiological joint damage, especially in individual patients. Methods: In active, early RA, IgM and IgA RFs, as well as erythrocyte sedimentation rate (ESR), C reactive protein (CRP), tender joint score, and swollen joint score were assessed regularly. At the study start and at 56 and 80 weeks, radiographs of hands and feet were assessed by the Sharp score (van der Heijde modification). Associations between RFs and disease activity parameters were studied. In addition, associations between radiographic damage and disease activity parameters (baseline and time integrated) were analysed by non-parametric tests and multiple regression analysis. The relation between time integrated disease activity parameters and radiological damage in individual patients was analysed and visualised. Results: 155 patients were included. RF levels were strongly associated with the disease activity parameters (especially ESR and CRP) and with each other. All disease activity parameters, at baseline as well as time integrated parameters, were associated with (the progression of) radiographic damage. Moreover, in individual patients, a linear relationship between time integrated disease activity parameters and progression of radiological damage was seen. Conclusion: RFs, measured as continuous variables, can be considered as disease activity parameters in patients with RA. The level of RF at baseline and the exposure to RF over time is associated with radiological damage. In individual patients, there is a constant relation between disease activity and radiological damage. PMID:12079900

  6. Radiation Forces and Torques without Stress (Tensors)

    ERIC Educational Resources Information Center

    Bohren, Craig F.

    2011-01-01

    To understand radiation forces and torques or to calculate them does not require invoking photon or electromagnetic field momentum transfer or stress tensors. According to continuum electromagnetic theory, forces and torques exerted by radiation are a consequence of electric and magnetic fields acting on charges and currents that the fields induce…

  7. Casimir torque on a cylindrical gear

    NASA Astrophysics Data System (ADS)

    Vaidya, Varun

    2014-08-01

    I utilize effective field theory(EFT) techniques to calculate the Casimir torque on a cylindrical gear in the presence of a polarizable but neutral object and present results for the energy and torque as a function of angle for a gear with multiple cogs, as well as for the case of a concentric cylindrical gear.

  8. 14 CFR 25.361 - Engine torque.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed...

  9. 14 CFR 25.361 - Engine torque.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed...

  10. 14 CFR 25.361 - Engine torque.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed...

  11. 14 CFR 25.361 - Engine torque.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed...

  12. 14 CFR 25.361 - Engine torque.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed...

  13. Effects of activating fluxes on the weld penetration and corrosion resistant property of laser welded joint of ferritic stainless steel

    NASA Astrophysics Data System (ADS)

    Wang, Yonghui; Hu, Shengsun; Shen, Junqi

    2015-10-01

    This study was based on the ferritic stainless steel SUS430. Under the parallel welding conditions, the critical penetration power values (CPPV) of 3mm steel plates with different surface-coating activating fluxes were tested. Results showed that, after coating with activating fluxes, such as ZrO2, CaCO3, CaF2 and CaO, the CPPV could reduce 100~250 W, which indicating the increases of the weld penetrations (WP). Nevertheless, the variation range of WP with or without activating fluxes was less than 16.7%. Compared with single-component ones, a multi-component activating flux composed of 50% ZrO2, 12.09% CaCO3, 10.43% CaO, and 27.49% MgO was testified to be much more efficient, the WP of which was about 2.3-fold of that without any activating fluxes. Furthermore, a FeCl3 spot corrosion experiment was carried out with samples cut from weld zone to test the effects of different activating fluxes on the corrosion resistant (CR) property of the laser welded joints. It was found that all kinds of activating fluxes could improve the CR of the welded joints. And, it was interesting to find that the effect of the mixed activating fluxes was inferior to those single-component ones. Among all the activating fluxes, the single-component of CaCO3 seemed to be the best in resisting corrosion. By means of Energy Dispersive Spectrometer (EDS) testing, it was found that the use of activating fluxes could effectively restrain the loss of Cr element of weld zone in the process of laser welding, thus greatly improving the CR of welded joints.

  14. Reduction of phase noise in nanowire spin orbit torque oscillators.

    PubMed

    Yang, Liu; Verba, Roman; Tiberkevich, Vasil; Schneider, Tobias; Smith, Andrew; Duan, Zheng; Youngblood, Brian; Lenz, Kilian; Lindner, Jürgen; Slavin, Andrei N; Krivorotov, Ilya N

    2015-11-23

    Spin torque oscillators (STOs) are compact, tunable sources of microwave radiation that serve as a test bed for studies of nonlinear magnetization dynamics at the nanometer length scale. The spin torque in an STO can be created by spin-orbit interaction, but low spectral purity of the microwave signals generated by spin orbit torque oscillators hinders practical applications of these magnetic nanodevices. Here we demonstrate a method for decreasing the phase noise of spin orbit torque oscillators based on Pt/Ni80Fe20 nanowires. We experimentally demonstrate that tapering of the nanowire, which serves as the STO active region, significantly decreases the spectral linewidth of the generated signal. We explain the observed linewidth narrowing in the framework of the Ginzburg-Landau auto-oscillator model. The model reveals that spatial non-uniformity of the spin current density in the tapered nanowire geometry hinders the excitation of higher order spin-wave modes, thus stabilizing the single-mode generation regime. This non-uniformity also generates a restoring force acting on the excited self-oscillatory mode, which reduces thermal fluctuations of the mode spatial position along the wire. Both these effects improve the STO spectral purity.

  15. Reduction of phase noise in nanowire spin orbit torque oscillators

    PubMed Central

    Yang, Liu; Verba, Roman; Tiberkevich, Vasil; Schneider, Tobias; Smith, Andrew; Duan, Zheng; Youngblood, Brian; Lenz, Kilian; Lindner, Jürgen; Slavin, Andrei N.; Krivorotov, Ilya N.

    2015-01-01

    Spin torque oscillators (STOs) are compact, tunable sources of microwave radiation that serve as a test bed for studies of nonlinear magnetization dynamics at the nanometer length scale. The spin torque in an STO can be created by spin-orbit interaction, but low spectral purity of the microwave signals generated by spin orbit torque oscillators hinders practical applications of these magnetic nanodevices. Here we demonstrate a method for decreasing the phase noise of spin orbit torque oscillators based on Pt/Ni80Fe20 nanowires. We experimentally demonstrate that tapering of the nanowire, which serves as the STO active region, significantly decreases the spectral linewidth of the generated signal. We explain the observed linewidth narrowing in the framework of the Ginzburg-Landau auto-oscillator model. The model reveals that spatial non-uniformity of the spin current density in the tapered nanowire geometry hinders the excitation of higher order spin-wave modes, thus stabilizing the single-mode generation regime. This non-uniformity also generates a restoring force acting on the excited self-oscillatory mode, which reduces thermal fluctuations of the mode spatial position along the wire. Both these effects improve the STO spectral purity. PMID:26592432

  16. The bHLH-PAS Transcription Factor Dysfusion Regulates Tarsal Joint Formation in Response to Notch Activity during Drosophila Leg Development

    PubMed Central

    Córdoba, Sergio; Estella, Carlos

    2014-01-01

    A characteristic of all arthropods is the presence of flexible structures called joints that connect all leg segments. Drosophila legs include two types of joints: the proximal or “true” joints that are motile due to the presence of muscle attachment and the distal joints that lack musculature. These joints are not only morphologically, functionally and evolutionarily different, but also the morphogenetic program that forms them is distinct. Development of both proximal and distal joints requires Notch activity; however, it is still unknown how this pathway can control the development of such homologous although distinct structures. Here we show that the bHLH-PAS transcription factor encoded by the gene dysfusion (dys), is expressed and absolutely required for tarsal joint development while it is dispensable for proximal joints. In the presumptive tarsal joints, Dys regulates the expression of the pro-apoptotic genes reaper and head involution defective and the expression of the RhoGTPases modulators, RhoGEf2 and RhoGap71E, thus directing key morphogenetic events required for tarsal joint development. When ectopically expressed, dys is able to induce some aspects of the morphogenetic program necessary for distal joint development such as fold formation and programmed cell death. This novel Dys function depends on its obligated partner Tango to activate the transcription of target genes. We also identified a dedicated dys cis-regulatory module that regulates dys expression in the tarsal presumptive leg joints through direct Su(H) binding. All these data place dys as a key player downstream of Notch, directing distal versus proximal joint morphogenesis. PMID:25329825

  17. Estimating Torque Imparted on Spacecraft Using Telemetry

    NASA Technical Reports Server (NTRS)

    Lee, Allan Y.; Wang, Eric K.; Macala, Glenn A.

    2013-01-01

    There have been a number of missions with spacecraft flying by planetary moons with atmospheres; there will be future missions with similar flybys. When a spacecraft such as Cassini flies by a moon with an atmosphere, the spacecraft will experience an atmospheric torque. This torque could be used to determine the density of the atmosphere. This is because the relation between the atmospheric torque vector and the atmosphere density could be established analytically using the mass properties of the spacecraft, known drag coefficient of objects in free-molecular flow, and the spacecraft velocity relative to the moon. The density estimated in this way could be used to check results measured by science instruments. Since the proposed methodology could estimate disturbance torque as small as 0.02 N-m, it could also be used to estimate disturbance torque imparted on the spacecraft during high-altitude flybys.

  18. In-line rotating capacitive torque sensor

    DOEpatents

    Kronberg, J.W.

    1991-09-10

    Disclosed are a method and apparatus for measuring torques developed along a rotating mechanical assembly comprising a rotating inner portion and a stationary outer portion. The rotating portion has an electrically-conductive flexing section fitted between two coaxial shafts in a configuration which varies radially in accordance with applied torque. The stationary portion comprises a plurality of conductive plates forming a surface concentric with and having a diameter slightly larger than the diameter of the rotating portion. The capacitance between the outer, nonrotating and inner, rotating portion varies with changes in the radial configuration of the rotating portion. Signal output varies approximately linearly with torque for small torques, nonlinearly for larger torques. The sensor is preferably surrounded by a conductive shell to minimize electrical interference from external sources. 18 figures.

  19. Torque requirement of rotating rods in airflow

    NASA Technical Reports Server (NTRS)

    Barna, P. S.; Crossman, G. R.

    1979-01-01

    Experiments were performed to determine the torque required for rotating a rotor disk fitted with a number of radially arranged rods placed into a ducted airflow. An array of stationary rods, also radially arranged, was placed upstream close to the rotor with a small gap between the rods to cause wake interference. The results show that torque generally increased with airflow and the rate of increase varied considerably. At lower values of airflow, the rate of increase was larger than at higher airflow, and definite torque peaks occurred at certain airflow rates, where the torque attained a maximum within the test airflow range. During the test, a maximum blade passage frequency of 2037 Hz was attained. The results also show that the torque peaks occurred at the same Strouhal number for all speeds.

  20. Torque transducer based on fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Li, Tao; Jiang, Shu; Li, Jiang; Lin, Jiejun; Qi, Hongli

    2016-11-01

    In order to obtain the accurate torque measurements in harsh condition, such as marine environment, a torque transducer based on fiber Bragg grating is proposed in this paper. According to its optimized elastomer design and fiber Bragg grati ng patching tactics, the new proposed torque transducer realizes automatic compensations of temperature and bending moment which avoids influences from environment. The accuracy and stability of the torquetransducer, as well as its under water performance are tested by loading tests both in air and in underwater environment, which indicate the designed tor que transducer is not only able to realize highaccurate and robust measurements, but also can be applied in torque sensing in harsh environment. We believe the proposed design detailed illustrated in this paper provides important reference for studies and applications on torque measurements in marine environment.

  1. In-line rotating capacitive torque sensor

    DOEpatents

    Kronberg, James W.

    1991-01-01

    A method and apparatus for measuring torques developed along a rotating mechanical assembly comprising a rotating inner portion and a stationary outer portion. The rotating portion has an electrically-conductive flexing section fitted between two coaxial shafts in a configuration which varies radially in accordance with applied torque. The stationary portion comprises a plurality of conductive plates forming a surface concentric with and having a diameter slightly larger than the diameter of the rotating portion. The capacitance between the outer, nonrotating and inner, rotating portion varies with changes in the radial configuration of the rotating portion. Signal output varies approximately linearly with torque for small torques, nonlinearly for larger torques. The sensor is preferably surrounded by a conductive shell to minimize electrical interference from external sources.

  2. RADIOACTIVE MATERIAL PACKAGING TORQUE REQUIREMENTS COMPLIANCE

    SciTech Connect

    Watkins, R.; Leduc, D.

    2011-03-24

    Shipping containers used to transport radioactive material (RAM) in commerce employ a variety of closure mechanisms. Often, these closure mechanisms require a specific amount of torque be applied to a bolt, nut or other threaded fastener. It is important that the required preload is achieved so that the package testing and analysis is not invalidated for the purpose of protecting the public. Torque compliance is a means of ensuring closure preload, is a major factor in accomplishing the package functions of confinement/containment, sub-criticality, and shielding. This paper will address the importance of applying proper torque to package closures, discuss torque value nomenclature, and present one methodology to ensure torque compliance is achieved.

  3. Muscle Activation Differs between Three Different Knee Joint-Angle Positions during a Maximal Isometric Back Squat Exercise

    PubMed Central

    Jarbas da Silva, Josinaldo; Jon Schoenfeld, Brad; Nardi, Priscyla Silva Monteiro; Pecoraro, Silvio Luis; D'Andréa Greve, Julia Maria; Hartigan, Erin

    2016-01-01

    The purpose of this study was to compare muscle activation of the lower limb muscles when performing a maximal isometric back squat exercise over three different positions. Fifteen young, healthy, resistance-trained men performed an isometric back squat at three knee joint angles (20°, 90°, and 140°) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), and gluteus maximus (GM). In general, muscle activity was the highest at 90° for the three quadriceps muscles, yet differences in muscle activation between knee angles were muscle specific. Activity of the GM was significantly greater at 20° and 90° compared to 140°. The BF and ST displayed similar activation at all joint angles. In conclusion, knee position alters muscles activation of the quadriceps and gluteus maximus muscles. An isometric back squat at 90° generates the highest overall muscle activation, yet an isometric back squat at 140° generates the lowest overall muscle activation of the VL and GM only. PMID:27504484

  4. Torque teno virus (TTV): current status.

    PubMed

    Hino, Shigeo; Miyata, Hironori

    2007-01-01

    Torque teno virus (TTV), currently classified into the family Circoviridae, genus Anellovirus, was first found in a patient with non-A-E hepatitis. TTV has a single stranded circular DNA of approximately 3.8 kb. TTVs are extraordinarily diverse, spanning five groups including SANBAN and SEN viruses. Torque teno mini virus (TTMV) with approximately 2.9 kb genome also has wide variants. Recently, two related 2.2- and 2.6-kb species joined this community. Recombinations between variants are frequent. This extensive TTV diversity remains unexplained; it is unclear how TTVs could be viable, and why they require such genetic variation. An unequivocal culture system is still not available. TTVs are ubiquitous in > 90% of adults worldwide but no human pathogenicity of TTV has been fully established. Epidemiological surveys need to specify the variants being studied and clinical targets, and must calibrate the sensitivity of the assay used. Potentially interesting observations include a higher viral load in patients with severe idiopathic inflammatory myopathies, cancer and lupus. Active replication was also found in infants with acute respiratory diseases. TTV/TTMV-related viruses were found in chimpanzees, apes, African monkeys and tupaias, and also in chickens, pigs, cows, sheep and dogs. Experimentally, rhesus monkeys were persistently infected by TTV, but only 1/53 chimpanzees. TTV transcribes three species of mRNAs, 3.0-, 1.2- and 1.0-kb in the ratio of 60:5:35. Recently, at least three mRNAs were shown in chicken anaemia virus. The genomic region -154/-76 contains a critical promoter. TTV seems to have at least three proteins; however, the definite functions of these proteins await further research work.

  5. A hybrid joint based controller for an upper extremity exoskeleton

    NASA Astrophysics Data System (ADS)

    Mohd Khairuddin, Ismail; Taha, Zahari; Majeed, Anwar P. P. Abdul; Hakeem Deboucha, Abdel; Azraai Mohd Razman, Mohd; Aziz Jaafar, Abdul; Mohamed, Zulkifli

    2016-02-01

    This paper presents the modelling and control of a two degree of freedom upper extremity exoskeleton. The Euler-Lagrange formulation was used in deriving the dynamic modelling of both the human upper limb as well as the exoskeleton that consists of the upper arm and the forearm. The human model is based on anthropometrical measurements of the upper limb. The proportional-derivative (PD) computed torque control (CTC) architecture is employed in this study to investigate its efficacy performing joint-space control objectives specifically in rehabilitating the elbow and shoulder joints along the sagittal plane. An active force control (AFC) algorithm is also incorporated into the PD-CTC to investigate the effectiveness of this hybrid system in compensating disturbances. It was found that the AFC- PD-CTC performs well against the disturbances introduced into the system whilst achieving acceptable trajectory tracking as compared to the conventional PD-CTC control architecture.

  6. Prediction of Large Joint Destruction in Patients With Rheumatoid Arthritis Using 18F-FDG PET/CT and Disease Activity Score.

    PubMed

    Suto, Takahito; Okamura, Koichi; Yonemoto, Yukio; Okura, Chisa; Tsushima, Yoshito; Takagishi, Kenji

    2016-02-01

    The assessments of joint damage in patients with rheumatoid arthritis (RA) are mainly restricted to small joints in the hands and feet. However, the development of arthritis in RA patients often involves the large joints, such as the shoulder, elbow, hip, knee, and ankle. Few studies have been reported regarding the degree of large joint destruction in RA patients. F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) visualizes the disease activity in large joints affected by RA. In this study, the associations between destruction of the large joints and the findings of FDG-PET/CT as well as laboratory parameters were investigated, and factors associated with large joint destruction after the administration of biological therapy were identified in RA patients. A total of 264 large joints in 23 RA patients (6 men and 17 women; mean age of 66.9 ± 7.9 years) were assessed in this study. FDG-PET/CT was performed at baseline and 6 months after the initiation of biological therapy. The extent of FDG uptake in large joints (shoulder, elbow, wrist, hip, knee, and ankle) was analyzed using the maximum standardized uptake value (SUVmax). Radiographs of the 12 large joints per patient obtained at baseline and after 2 years were assessed according to Larsen's method. A logistic regression analysis was performed to determine the factors most significantly contributing to the progression of joint destruction within 2 years. Radiographic progression of joint destruction was detected in 33 joints. The SUVmax at baseline and 6 months, and the disease activity score (DAS) 28-erythrocyte sedimentation rate (ESR) at 6, 12, and 24 months were significantly higher in the group with progressive joint destruction. The SUVmax at baseline and DAS28-ESR at 6 months were found to be factors associated with joint destruction at 2 years (P < 0.05). The FDG uptake in the joints with destruction was higher than that observed in the joints

  7. Microstructure and Performance of Kovar/Alumina Joints Made with Silver-Copper Base Active Metal Braze Alloys

    SciTech Connect

    STEPHENS, JOHN J.; VIANCO,PAUL T.; HLAVA,PAUL F.; WALKER,CHARLES A.

    1999-12-15

    Poor hermeticity performance was observed for Al{sub 2}O{sub 3}-Al{sub 2}O{sub 3} ceramic-ceramic joints having a Kovar{trademark} alloy interlayer. The active Ag-Cu-Ti filler metal was used to braze the substrates together. The Ti active element was scavenged from the filler metal by the formation of a (Fe, Ni, Co){sub x}Ti phase (x= 2-3) that prevented development of a continuous Ti{sub x}O{sub y} layer at the filler metal/Al{sub 2}O{sub 3} interface. Altering the process parameters did not circumvent the scavenging of Ti. Molybdenum barrier layers 1000, 2500, or 5000 {angstrom} thick on the Kovar{trademark} surfaces successfully allowed Ti{sub x}O{sub y} formation at the filler metal/Al{sub 2}O{sub 3} interface and hermetic joints. The problems with the Ag-Cu-Ti filler metal for Kovar{trademark}/Al{sub 2}O{sub 3} braze joints led to the evaluation of a Ag-Cu-Zr filler metal. The Zr (active element) in Ag-Cu-Zr filler metal was not susceptible to the scavenging problem.

  8. Visual Feedback of the Non-Moving Limb Improves Active Joint-Position Sense of the Impaired Limb in Spastic Hemiparetic Cerebral Palsy

    ERIC Educational Resources Information Center

    Smorenburg, Ana R. P.; Ledebt, Annick; Deconinck, Frederik J. A.; Savelsbergh, Geert J. P.

    2011-01-01

    This study examined the active joint-position sense in children with Spastic Hemiparetic Cerebral Palsy (SHCP) and the effect of static visual feedback and static mirror visual feedback, of the non-moving limb, on the joint-position sense. Participants were asked to match the position of one upper limb with that of the contralateral limb. The task…

  9. Can generic knee joint models improve the measurement of osteoarthritic knee kinematics during squatting activity?

    PubMed

    Clément, Julien; Dumas, Raphaël; Hagemeister, Nicola; de Guise, Jaques A

    2017-01-01

    Knee joint kinematics derived from multi-body optimisation (MBO) still requires evaluation. The objective of this study was to corroborate model-derived kinematics of osteoarthritic knees obtained using four generic knee joint models used in musculoskeletal modelling - spherical, hinge, degree-of-freedom coupling curves and parallel mechanism - against reference knee kinematics measured by stereo-radiography. Root mean square errors ranged from 0.7° to 23.4° for knee rotations and from 0.6 to 9.0 mm for knee displacements. Model-derived knee kinematics computed from generic knee joint models was inaccurate. Future developments and experiments should improve the reliability of osteoarthritic knee models in MBO and musculoskeletal modelling.

  10. ACTIVATION OF B-CATENIN SIGNALLING LEADS TO TEMPOROMANDIBULAR JOINT DEFECTS

    PubMed Central

    Wang, M.; Li, S.; Xie, W.; Shen, J.; Im, H-J.; Holz, J.D.; Wang, M.; Diekwisch, T.G.H.; Chen, D.

    2014-01-01

    Despite extensive research in knee and hip osteoarthritis (OA), the underlying mechanism of temporomandibular joint (TMJ) disorder remains largely unknown. The purpose of this study was to determine whether the constitutive activation of β-catenin in the middle and deep layers of the articular cartilage can compromise the homeostasis of this tissue in the TMJ. Co12CreERT2 transgenic mice were bred with RosamT/mG reporter mice to determine Cre recombination efficiency. Co12CreERT2 mice were then crossed with β-cateninflox (ex3)/+ mice to generate β-catenin conditional activation mice, β-catenin(ex3)Co12ER. TMJ samples were harvested when the mice were 1-, 3- or 6-month-old and evaluated using histology, histomorphometry and immunohistochemistry. β-catenin(ex3)Co12ER mice were further crossed with Mmp13flox/flox and Adamts5−/− mice to generate β-catenin(ex3)/Mmp13)Co12ER and β-catenin(ex3)Co12ER)/Adamts5−/− double mutant mice to investigate the role of Mmp13 and Adamts5 in the development of TMJ disorder. High levels of Cre-recombination were seen in Co12CreERT2;RosamT/mG mice. Progressive TMJ defects developed in 1-, 3- and 6-month-old β-catenin(ex3)Co12ER mice, as revealed by histology and histomorphometry. Results further demonstrated that the defects observed in β-catenin(ex3)Co12ER mice were significantly decelerated after deletion of the Mmp13 or Adamts5 gene in (β-catenin(ex3)/Mmp13)co12ER or β-catenin(ex3)Co12ER/ Adamts5−/− double mutant mice. In summary, we found that β-catenin is a critical gene in the induction of TMJ cartilage degeneration, and over-expressing β-catenin in TMJ cartilage leads to defects assembling an OA-like phenotype. Deletion of Mmp13 and Adamts5 in β-catenin(ex3)Co12ER mice ameliorates the development of TMJ defects. This study suggests that Mmp13 and Adamts5 could be potential therapeutic targets for the treatment of TMJ disorders. PMID:25340802

  11. Effect of Multipass TIG and Activated TIG Welding Process on the Thermo-Mechanical Behavior of 316LN Stainless Steel Weld Joints

    NASA Astrophysics Data System (ADS)

    Ganesh, K. C.; Balasubramanian, K. R.; Vasudevan, M.; Vasantharaja, P.; Chandrasekhar, N.

    2016-04-01

    The primary objective of this work was to develop a finite element model to predict the thermo-mechanical behavior of an activated tungsten inert gas (ATIG)-welded joint. The ATIG-welded joint was fabricated using 10 mm thickness of 316LN stainless steel plates in a single pass. To distinguish the merits of ATIG welding process, it was compared with manual multipass tungsten inert gas (MPTIG)-welded joint. The ATIG-welded joint was fabricated with square butt edge configuration using an activating flux developed in-house. The MPTIG-welded joint was fabricated in thirteen passes with V-groove edge configuration. The finite element model was developed to predict the transient temperature, residual stress, and distortion of the welded joints. Also, microhardness, impact toughness, tensile strength, ferrite measurement, and microstructure were characterized. Since most of the recent publications of ATIG-welded joint was focused on the molten weld pool dynamics, this research work gives an insight on the thermo-mechanical behavior of ATIG-welded joint over MPTIG-welded joint.

  12. Human joint motion estimation for electromyography (EMG)-based dynamic motion control.

    PubMed

    Zhang, Qin; Hosoda, Ryo; Venture, Gentiane

    2013-01-01

    This study aims to investigate a joint motion estimation method from Electromyography (EMG) signals during dynamic movement. In most EMG-based humanoid or prosthetics control systems, EMG features were directly or indirectly used to trigger intended motions. However, both physiological and nonphysiological factors can influence EMG characteristics during dynamic movements, resulting in subject-specific, non-stationary and crosstalk problems. Particularly, when motion velocity and/or joint torque are not constrained, joint motion estimation from EMG signals are more challenging. In this paper, we propose a joint motion estimation method based on muscle activation recorded from a pair of agonist and antagonist muscles of the joint. A linear state-space model with multi input single output is proposed to map the muscle activity to joint motion. An adaptive estimation method is proposed to train the model. The estimation performance is evaluated in performing a single elbow flexion-extension movement in two subjects. All the results in two subjects at two load levels indicate the feasibility and suitability of the proposed method in joint motion estimation. The estimation root-mean-square error is within 8.3% ∼ 10.6%, which is lower than that being reported in several previous studies. Moreover, this method is able to overcome subject-specific problem and compensate non-stationary EMG properties.

  13. PREFACE: The Science of Making Torque from Wind 2012

    NASA Astrophysics Data System (ADS)

    2014-12-01

    The European Academy of Wind Energy (eawe) was pleased to announce its 4th scientific conference The Science of Making Torque from Wind. Predecessors have successfully been arranged in Delft, The Netherlands (2004), Lyngby, Denmark (2007) and Heraklion, Greece (2010). During the years the Torque Conference has established itself as Europe's leading scientific wind energy conference. The 2012 edition had been organized in the same tradition. More than 300 experts from academia and industry discussed the latest results and developments in fundamental and applied wind energy research, making this Science of Making Torque from Wind conference the largest one to that date. The seven keynote lectures provided the delegates with a unique overview on the state-of-the-art of science and technology. In over twenty sessions the participants discussed the most recent results in wind energy research. From numerical models to sophisticated experiments, from flow optimizations to structural designs, the numerous presentations covered a huge spectrum of ongoing scientific activities. The proceedings of the Torque 2012 combine the 110 papers that have passed the review process. We would like to thank all those who have been involved in organizing the conference and putting together these proceedings, including keynote speakers, session chairs and the enormous amount of reviewers involved. We are especially grateful to Gijs van Kuik for his untiring support. We also deeply appreciate the logistical support and technical services of the University of Oldenburg and the financial support of the State of Lower Saxony. At IOP we would like to thank Anete Ashton for her continuous encouraging support. We are looking forward to all future Torque Conferences, offering an excellent platform for the exchange of the latest and greatest scientific developments in the field of wind energy. Oldenburg, Germany, October 2014 Elke Seidel, Detlev Heinemann, Martin Kühn, Joachim Peinke and Stephan

  14. Research on new dynamic torque calibration system

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Wang, Zhong Yu; Yin, Xiao

    2016-06-01

    Dynamic torque calibration method based on rotating table and interferometric system is studied in this paper. A load mass with certain moment of inertia are screwed on the top of torque transducer, the dynamic torque is realized by load object are traceable to angular acceleration and moment of inertia of the object by M (t)=I θ ¨(t) , where I is the total moment of inertia acting on the sensing element of the torque transducer and θ ¨ is the time and spatial-dependent angular acceleration of the load object which is directly measured by a laser interferometer. This paper will introduce a dynamic torque calibration system developed at Changcheng Institute of Metrology and Measurement (CIMM). It uses servomotor to generate dynamic torque in the range from 0.1Nm to 200Nm, and heterodyne laser interferometers cooperated with column grating are used for angular acceleration measurement. An airbearing system is developed to increase the performance of the dynamic turque calibration system. This paper introduce the setup of the dynamic torque calibration system.

  15. Switching Torque Converter: Concept and Preliminary Implementation

    NASA Astrophysics Data System (ADS)

    Hirota, Koichi; Ikei, Yasushi

    It is preferable to refrain from switching the torque in mechanical systems because the abrupt change tends to cause vibration and noise. However, such vibration can be beneficial if it is used to store mechanical energy. Moreover, torque switching operations at higher frequencies are becoming possible because of the recent advances in clutch devices. This paper describes a novel torque conversion mechanism based on torque switching operations. The fundamental principle of the mechanism is the reciprocal translation between the work to and from axles and the rotational energy of a flywheel. Clutches are used to intermittently connect or disconnect the axles with the flywheel; the output torque is controlled by changing the time ratio of the connection. By performing switching operations at a higher frequency, almost continuous torque conversion can be realized. A prototype was created using electrorheological fluid clutches, and it showed the potential for torque conversion. The performance of the prototype was also analyzed by numerical simulation; this showed that the prototype worked in accordance with the principle. Moreover, the potential capability of the principle was investigated using a numerical model and the results suggest that by improving the mechanical design, a considerable improvement in performance is possible.

  16. Torque Ripple Reduction of Reluctance Torque Assisted Motors Using Asymmetric Flux Barriers

    NASA Astrophysics Data System (ADS)

    Hiramoto, Kenji; Takeda, Yoji; Sanada, Masayuki; Morimoto, Shigeo

    Interior permanent magnet synchronous motor (IPMSM) is efficient and can be operated in wide speed region; therefore it is used widely. However, torque ripple of reluctance torque assisted motors, for example IPMSM and synchronous reluctance motor (SynRM), is very large. The skew is known in the prior art as a torque ripple reduction method of AC motors. Although the skew is effective for torque ripple reduction, structure is complicated and it has the disadvantage that average torque will decrease. The discontinuous variation of magnetic resistance between flux barriers and teeth cause the torque ripple. In this paper, in order to ease the discontinuous variation of magnetic resistance, flux barriers are asymmetrically designed so that the relative position relation between flux barriers and teeth may not be in agreement as much as possible. As a result, the torque ripple can be reduced dramatically without the average torque decrease. The experimental motor has been fabricated and the results of measuring torque ripple prove the validity of the torque ripple reduction using asymmetric flux barriers.

  17. The use of focal knee joint cryotherapy to improve functional outcomes after total knee arthroplasty: review article.

    PubMed

    Ewell, Melvin; Griffin, Christopher; Hull, Jason

    2014-08-01

    The purpose of this study was to review and synthesize available evidence on the effect of focal knee joint cryotherapy on quadriceps arthrogenic muscle inhibition and to discuss the implications of the findings regarding the use of this modality for patients after a total knee arthroplasty. An electronic literature search that targeted peer reviewed journals was completed by using the PubMed, CINAHL, ScienceDirect, and OvidSP databases. An article was included when it was determined that the article was relevant to the topic of focal knee joint cryotherapy and its effect on quadriceps muscle function. There were 6 studies that met the inclusion criteria. Of the reviewed studies, effect sizes for quadriceps activation ranged from very small to large. Five of the 6 studies observed medium to large effects. Effect sizes for quadriceps torque and force production ranged from no effect to a large effect. Two of the 5 studies with outcome measurements related to quadriceps torque or force production observed medium and large effects. Analysis of this evidence suggests that focal joint cooling of the knee shows the potential to improve quadriceps activation as well as quadriceps torque and force production in patients with arthrogenic muscle inhibition. Arthrogenic muscle inhibition of the quadriceps is an impairment commonly observed in patients after a total knee arthroplasty. Analysis of the evidence uncovered in this review suggests that this patient population may be positively impacted by the use of this modality to improve quadriceps activation as well as quadriceps torque and force production.

  18. Current Activities Assessing Butt Fusion Joint Integrity in High Density Polyethylene Piping

    SciTech Connect

    Crawford, Susan L.; Cinson, Anthony D.; Doctor, Steven R.; Denslow, Kayte M.

    2012-09-01

    The Pacific Northwest National Laboratory (PNNL) in Richland, Washington, conducted initial studies to evaluate the effectiveness of nondestructive examinations (NDE) coupled with mechanical testing for assessing butt fusion joint integrity in high density polyethylene (HDPE) pipe. The work provided insightful information to the United States Nuclear Regulatory Commission (NRC) on the effectiveness of volumetric inspection techniques for detecting lack of fusion (LOF) conditions in the fusion joints. HDPE has been installed on a limited basis in American Society of Mechanical Engineers (ASME) Class 3, buried piping systems at several operating U.S. nuclear power plants and has been proposed for use in new construction. A comparison was made between the results from ultrasonic and microwave nondestructive examinations and the results from mechanical destructive evaluations, specifically the high-speed tensile test and the side-bend test, for determining joint integrity. The data comparison revealed that none of the NDE techniques detected all of the lack-of-fusion conditions that were revealed by the destructive tests. Follow-on work has recently been initiated at PNNL to accurately characterize the NDE responses from machined flaws of varying size and location in PE 4710 materials as well as the LOF condition. This effort is directed at quantifying the ability of volumetric NDE techniques to detect flaws in relation to the critical flaw size associated with joint integrity. A status of these latest investigations is presented.

  19. Hamlet without the Prince: Shortcomings of an Activity-Based Account of Joint Attention

    ERIC Educational Resources Information Center

    Hobson, R. Peter

    2007-01-01

    In this commentary, I consider several strengths of the position adopted by Racine and Carpendale (2007), but suggest that the authors are in danger of overstating their case. In doing so, they appear to sideline an issue that should be pivotal for accounts of joint attention: how does a child come to arrive at an understanding that people, both…

  20. Changes in the activity of trunk and hip extensor muscles during bridge exercises with variations in unilateral knee joint angle

    PubMed Central

    Kim, Juseung; Park, Minchul

    2016-01-01

    [Purpose] This study compared abdominal and hip extensor muscle activity during a bridge exercise with various knee joint angles. [Subjects and Methods] Twenty-two healthy male subjects performed a bridge exercise in which the knee joint angle was altered. While subjects performed the bridge exercise, external oblique, internal oblique, gluteus maximus, and semitendinosus muscle activity was measured using electromyography. [Results] The bilateral external and internal oblique muscle activity was significantly higher at 0° knee flexion compared to 120°, 90°, and 60°. The bilateral gluteus maximus muscle activity was significantly different at 0° of knee flexion compared to 120°, 90°, and 60°. The ipsilateral semitendinosus muscle activity was significantly increased at 90° and 60° of knee flexion compared to 120°, and significantly decreased at 0° knee flexion compared with 120°, 90°, and 60°. The contralateral semitendinosus muscle activity was significantly higher at 60° of knee flexion than at 120°, and significantly higher at 0° of knee flexion than at 120°, 90°, and 60°. [Conclusion] Bridge exercises performed with knee flexion less than 90° may be used to train the ipsilateral semitendinosus. Furthermore, bridge exercise performed with one leg may be used to train abdominal and hip extensor muscles. PMID:27799688

  1. Magnetic torque on a rotating superconducting sphere

    NASA Technical Reports Server (NTRS)

    Holdeman, L. B.

    1975-01-01

    The London theory of superconductivity is used to calculate the torque on a superconducting sphere rotating in a uniform applied magnetic field. The London theory is combined with classical electrodynamics for a calculation of the direct effect of excess charge on a rotating superconducting sphere. Classical electrodynamics, with the assumption of a perfect Meissner effect, is used to calculate the torque on a superconducting sphere rotating in an arbitrary magnetic induction; this macroscopic approach yields results which are correct to first order. Using the same approach, the torque due to a current loop encircling the rotating sphere is calculated.

  2. Rotational joint assembly for the prosthetic leg

    NASA Technical Reports Server (NTRS)

    Owens, L. J.; Jones, W. C. (Inventor)

    1977-01-01

    A rotational joint assembly for a prosthetic leg has been devised, which enables an artificial foot to rotate slightly when a person is walking, running or turning. The prosthetic leg includes upper and lower tubular members with the rotational joint assembly interposed between them. The assembly includes a restrainer mechanism which consists of a pivotably mounted paddle element. This device applies limiting force to control the rotation of the foot and also restores torque to return the foot back to its initial position.

  3. Inflammation and Bone Destruction in Arthritis: Synergistic Activity of Immune and Mesenchymal Cells in Joints

    PubMed Central

    Komatsu, Noriko; Takayanagi, Hiroshi

    2012-01-01

    Rheumatoid arthritis (RA) is an immune-mediated disease of the joints that is characterized by chronic inflammation and synovial hyperplasia that eventually lead to cartilage and bone destruction. Synovial fibroblasts are mesenchymal cells recognized as a key cell population in RA due to their hyperproliferative and hypersensitive properties in the inflammatory milieu and hyperproduction of both inflammatory cytokines and matrix-degrading enzymes. On the immune cell side, a wealth of evidence has shown that CD4+T-cells, especially IL-17 producing helper T (Th17) cells, play a prominent role, particularly in the initiation of systemic immune response in RA. However, it is still unclear how the local chronic inflammation in the joint is elicited by a systemic immune response. Recent studies have shed light on the importance of the interaction between immune and mesenchymal cells in joints including synovial fibroblasts. In particular, mesenchymal cells contribute to the Th17-mediated chronic inflammation in RA by promoting the migration of Th17 cells to the inflamed site and then the homeostatic proliferation and concomitant increase in IL-17 production. In addition, recent progress in osteoimmunology has provided new insight into the pathogenesis of the bone destruction which takes place in RA. Th17-related cytokines have been shown to enhance osteoclastogenesis, mainly via synovial fibroblasts. Thus, mesenchymal cells are a determinant of the development of RA that links the systemic immune response and the local disorder in the joints. In addition, the interaction of immune and mesenchymal cells plays a key role in both the chronic inflammation and bone destruction seen in RA. Elucidation of the precise events involved in this interaction will lead to a better understanding of the mechanisms by which chronic inflammation and bone destruction in joint results from a systemic immune response, and also will help provide a molecular basis for novel therapeutic

  4. Do patients with juvenile idiopathic arthritis in remission exhibit active synovitis on joint ultrasound?

    PubMed

    Bugni Miotto e Silva, Vanessa; de Freitas Tavares da Silva, Carolina; de Aguiar Vilela Mitraud, Sônia; Nely Vilar Furtado, Rita; Esteves Hilário, Maria Odete; Natour, Jamil; Terreri, Maria Teresa

    2014-07-01

    The aim of the study was to assess the presence and characteristics of subclinical synovitis using power Doppler (PD) ultrasonography on patients with juvenile idiopathic arthritis (JIA) in clinical remission and compare the findings with those of healthy children. A cross-sectional study was carried out involving the clinical (physical exam, functional capacity and laboratory tests) and ultrasonography evaluation of 34 joints (synovial fluid/hypertrophy, PD signal and bone erosion). Subclinical synovitis was defined as the presence of synovial hypertrophy/joint effusion with or without any PD signal. Thirty-six patients (11.5 ± 3.74 years) and 36 controls (sex and age matched) were evaluated (2,448 joints). Twenty-seven patients were in remission on medication (mean duration: 1.8 ± 2.2 years). Subclinical synovitis was detected in 41.7% patients and 11.1% controls (p = 0.003). Erosion was detected in three patients (8.3%). Subclinical synovitis was found in 38/1,224 (3.1%) joints in the patients (most affected: radiocarpal wrist, anterior elbow and tibiotalar ankle) and 8/1,224 (0.6%) joints in the controls (most affected: radiocarpal wrist). Differences in subclinical synovitis between patients and controls were found in the elbows (p = 0.033) and ankles (p = 0.006). A greater frequency of subclinical synovitis was found in patients with the extended oligoarticular or polyarticular subtypes (p = 0.013), those at an older age at disease onset (p = 0.007) and using methotrexate (p = 0.049). Patients with JIA in remission exhibit subclinical synovitis more frequently than controls. Subclinical synovitis was more frequent in patients with the polyarticular involvement and those at an older age at disease onset.

  5. Active and passive characteristics of muscle tone and their relationship to models of subluxation/joint dysfunction

    PubMed Central

    Knutson, Gary A.; Owens, Edward F.

    2003-01-01

    The relationship of muscles to the causes and effects of the pathophysiologic entity referred to as chiropractic subluxation or joint dysfunction is critical. Part I of this paper reviewed the complexities of skeletal muscle in regards to anatomy, active and passive tone, detection of muscle tone, neurophysiology, and how muscle function fits into a variety of subluxation/joint dysfunction models. The concluding part of the review culminates in a hypothesis to describe and explain varying degrees of muscle tone that may be encountered clinically. It is hoped that knowledge of the differing levels of muscle tone and their causes will help the clinician to better determine the underlying cause of a neuromusculoskeletal problem allowing application of necessary and proper intervention.

  6. Active and passive characteristics of muscle tone and their relationship to models of subluxation/joint dysfunction

    PubMed Central

    Knutson, Gary A; Owens, Edward F

    2003-01-01

    The relationship of muscles to the causes and effects of the pathophysiologic entity referred to as chiropractic subluxation or joint dysfunction is critical. Part I of this paper reviews complexities of skeletal muscle in regards to anatomy, active and passive tone, detection of muscle tone, neurophysiology, and how muscle function fits into a variety of subluxation/joint dysfunction models. The review culminates in Part II with a hypothesis to describe and explain varying degrees of muscle tone that may be encountered clinically. It is hoped that knowledge of the differing levels of muscle tone and their causes will help the clinician to better determine the underlying cause of a neuro-musculoskeletal problem allowing application of necessary and proper intervention. Imagesp179-a

  7. Determining the shear fracture properties of HIP joints of reduced-activation ferritic/martensitic steel by a torsion test

    NASA Astrophysics Data System (ADS)

    Nozawa, Takashi; Noh, Sanghoon; Tanigawa, Hiroyasu

    2012-08-01

    Hot isostatic pressing (HIP) is a key technology used to fabricate a first wall with cooling channels for the fusion blanket system utilizing a reduced-activation ferritic/martensitic steel. To qualify the HIPped components, small specimen test techniques are beneficial not only to evaluate the thin-wall cooling channels containing the HIP joint but also to use in neutron irradiation studies. This study aims to develop the torsion test method with special emphasis on providing a reasonable and comprehensive method to determine interfacial shear properties of HIP joints during the torsional fracture process. Torsion test results identified that the torsion process shows yield of the base metal followed by non-elastic deformation due to work hardening of the base metal. By considering this work hardening issue, we propose a reasonable and realistic solution to determine the torsional yield shear stress and the ultimate torsional shear strength of the HIPped interface. Finally, a representative torsion fracture process was identified.

  8. Torque exerted on the side of crustal blocks controls the kinematics of Ethiopian Rift

    NASA Astrophysics Data System (ADS)

    Muluneh, Ameha A.; Kidane, Tesfaye; Cuffaro, Marco; Doglioni, Carlo

    2016-04-01

    Plate tectonic stress at active plate boundary can arises from 1) a torque applied on the side of lithospheric blocks and 2) a torque at the base of the lithosphere due to the flow of the underlying mantle. In this paper we use a simple force balance analysis to compare side and basal shear stresses and their contribution in driving kinematics and deformation in the Ethiopian Rift (ER), in the northern part of the East African Rift System (EARS). Assuming the constraints of the ER given by the dimension of the lithospheric blocks, the strain rate, the viscosity of the low velocity zone (LVZ) and the depth of the brittle-ductile transition zone, the lateral torque is several orders of magnitude higher than the basal torque. The minor contribution of basal torque might be due to low viscosity in the LVZ. Both Africa and Somalia plates are moving to the "west" relative to the mantle and there are not slabs that can justify this pull and consequent motion. Therefore, we invoke that westerly oriented tidal torque on Africa and Somalia plates in providing the necessary side torque in the region. This plate motion predicts significant sinistral transtension along the ER and rift parallel strike-slip faulting similar to the estimated angular velocity vector for tectonic blocks and GPS observations. Vertical axis block rotations are observed in areas where the lithospheric mantle is removed and strain is widely distributed.

  9. Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions.

    PubMed

    Tsuruike, Masaaki; Ellenbecker, Todd

    2014-11-14

    Context :  Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. Objective :  To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Design :  Cross-sectional study. Setting :  Health Science Laboratory. Patients or Other Participants :  A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Main Outcome Measure(s) :  Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Results :  Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Conclusions :  Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.

  10. Effect of Activated Flux on the Microstructure, Mechanical Properties, and Residual Stresses of Modified 9Cr-1Mo Steel Weld Joints

    NASA Astrophysics Data System (ADS)

    Maduraimuthu, V.; Vasudevan, M.; Muthupandi, V.; Bhaduri, A. K.; Jayakumar, T.

    2012-02-01

    A novel variant of tungsten inert gas (TIG) welding called activated-TIG (A-TIG) welding, which uses a thin layer of activated flux coating applied on the joint area prior to welding, is known to enhance the depth of penetration during autogenous TIG welding and overcomes the limitation associated with TIG welding of modified 9Cr-1Mo steels. Therefore, it is necessary to develop a specific activated flux for enhancing the depth of penetration during autogeneous TIG welding of modified 9Cr-1Mo steel. In the current work, activated flux composition is optimized to achieve 6 mm depth of penetration in single-pass TIG welding at minimum heat input possible. Then square butt weld joints are made for 6-mm-thick and 10-mm-thick plates using the optimized flux. The effect of flux on the microstructure, mechanical properties, and residual stresses of the A-TIG weld joint is studied by comparing it with that of the weld joints made by conventional multipass TIG welding process using matching filler wire. Welded microstructure in the A-TIG weld joint is coarser because of the higher peak temperature in A-TIG welding process compared with that of multipass TIG weld joint made by a conventional TIG welding process. Transverse strength properties of the modified 9Cr-1Mo steel weld produced by A-TIG welding exceeded the minimum specified strength values of the base materials. The average toughness values of A-TIG weld joints are lower compared with that of the base metal and multipass weld joints due to the presence of δ-ferrite and inclusions in the weld metal caused by the flux. Compressive residual stresses are observed in the fusion zone of A-TIG weld joint, whereas tensile residual stresses are observed in the multipass TIG weld joint.

  11. Effects of Nordic walking on pelvis motion and muscle activities around the hip joints of adults with hip osteoarthritis

    PubMed Central

    Homma, Daisuke; Jigami, Hirofumi; Sato, Naritoshi

    2016-01-01

    [Purpose] Increased compensatory pelvic movement is remarkable in limping patients with hip osteoarthritis (OA). However, a method of improving limping has not been established. The purpose of this study was to identify the effects of two types of Nordic walking by analyzing the pelvic movement and muscle activities of adults with hip OA. [Subjects and Methods] Ten patients with OA of the hip performed Japanese-style Nordic walking (JS NW), European-style Nordic walking (ES NW), and Ordinary walking (OW), and the muscle activities around the hip joint and pelvic movements were analyzed. [Results] The pelvic rotation angle was significantly larger in ES NW than in JS NW. In the stance phase, hip abductor muscle activity was significantly decreased in JS NW compared to both OW and ES NW. In the swing phase, rectus abdominis muscle activity was significantly increased in both JS NW and ES NW compared to OW and lumbar erector spinae activity was significantly lower in JS NW than in OW. [Conclusion] JS NW style may reduce the compensatory pelvic rotation in patients with hip OA. JS NW might be better for joint protection and prevention of secondary disorders of the hip in OA patients. PMID:27190455

  12. Comparing passive angle-torque curves recorded simultaneously with a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments.

    PubMed

    Buckner, Samuel L; Jenkins, Nathaniel D M; Costa, Pablo B; Ryan, Eric D; Herda, Trent J; Cramer, Joel T

    2015-05-01

    The purpose of the present study was to compare the passive angle-torque curves and the passive stiffness (PS, N m °(-)(1)) values recorded simultaneously from a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments in vivo. Nine healthy men (mean ± SD age = 21.4 ± 1.6 years) completed stretch tolerance assessments on a custom-built apparatus where passive torque was measured simultaneously from an isokinetic dynamometer and a load cell. Passive torque values that corresponded with the last 10° of dorsiflexion, verified by surface electromyographic amplitude, were analyzed for each device (θ1, θ2, θ3, …, θ10). Passive torque values measured with the load cell were greater (p ≤ 0.05) than the dynamometer torque values for θ4 through θ10. There were more statistical differentiations among joint angles for passive torque measured by the load cell, and the load cell measured a greater (p ≤ 0.01) increase in passive torque and PS than the isokinetic dynamometer. These findings suggested that when examining the angle-torque curves from passive dorsiflexion stretch tolerance tests, a load cell placed under the distal end of the foot may be more sensitive than the torque recorded from an isokinetic dynamometer.

  13. Increasing Elbow Torque Output of Stroke Patients by EMG-Controlled External Torque

    DTIC Science & Technology

    2007-11-02

    Abstract- A control algorithm for using homogenic EMG to control external assisting torque is developed for improving the elbow capability of...sacrificing performance. Keywords - Elbow , EMG, assisting torque, stroke I. INTRODUCTION Hemiparesis, which means partial loss of muscle strength...system to increase the total torque capability of the elbow for this class of patients. The system was controlled by surface EMG of biceps and

  14. Damping assembly for a torque converter clutch

    SciTech Connect

    Dull, D.C.

    1989-12-26

    This patent describes a turbine damped torque converter and clutch. It comprises: a pressure plate; a torque converter turbine; a torque converter impeller; means including a control chamber for the pressure plate means for controlling the apply and release of the clutch for engaging the clutch with the impeller; a torque converter output shaft; a planetary gear arrangement including an input gear drivingly connected with the pressure plate, a reaction gear drivingly connected with the turbine, an output member drivingly connected with the output shaft and pinion gear means meshing with the input gear and the reaction gear for drivingly interconnecting the turbine and the pressure plate at a drive ratio of the turbine to the pressure plate of less than 1:1; and one-way drive means disposed between the turbine and the output shaft for preventing the turbine from overrunning the output shaft.

  15. Torque equilibrium attitude control for Skylab reentry

    NASA Technical Reports Server (NTRS)

    Glaese, J. R.; Kennel, H. F.

    1979-01-01

    All the available torque equilibrium attitudes (most were useless from the standpoint of lack of electrical power) and the equilibrium seeking method are presented, as well as the actual successful application during the 3 weeks prior to Skylab reentry.

  16. Fundamental limits of optical force and torque

    NASA Astrophysics Data System (ADS)

    Rahimzadegan, A.; Alaee, R.; Fernandez-Corbaton, I.; Rockstuhl, C.

    2017-01-01

    Optical force and torque provide unprecedented control on the spatial motion of small particles. A valid scientific question, that has many practical implications, concerns the existence of fundamental upper bounds for the achievable force and torque exerted by a plane wave illumination with a given intensity. Here, while studying isotropic particles, we show that different light-matter interaction channels contribute to the exerted force and torque, and analytically derive upper bounds for each of the contributions. Specific examples for particles that achieve those upper bounds are provided. We study how and to which extent different contributions can add up to result in the maximum optical force and torque. Our insights are important for applications ranging from molecular sorting, particle manipulation, and nanorobotics up to ambitious projects such as laser-propelled spaceships.

  17. Transmission of torque at the nanoscale

    NASA Astrophysics Data System (ADS)

    Williams, Ian; Oğuz, Erdal C.; Speck, Thomas; Bartlett, Paul; Löwen, Hartmut; Royall, C. Patrick

    2016-01-01

    In macroscopic mechanical devices, torque is transmitted through gearwheels and clutches. In the construction of devices at the nanoscale, torque and its transmission through soft materials will be a key component. However, this regime is dominated by thermal fluctuations leading to dissipation. Here we demonstrate the principle of torque transmission for a disc-like colloidal assembly exhibiting clutch-like behaviour, driven by 27 particles in optical traps. These are translated on a circular path to form a rotating boundary that transmits torque to additional particles confined to the interior. We investigate this transmission and find that it is determined by solid-like or fluid-like behaviour of the device and a stick-slip mechanism reminiscent of macroscopic gearwheels slipping. The transmission behaviour is predominantly governed by the rotation rate of the boundary and the density of the confined system. We determine the efficiency of our device and thus optimize conditions to maximize power output.

  18. Torque-mixing magnetic resonance spectroscopy.

    PubMed

    Losby, J E; Fani Sani, F; Grandmont, D T; Diao, Z; Belov, M; Burgess, J A J; Compton, S R; Hiebert, W K; Vick, D; Mohammad, K; Salimi, E; Bridges, G E; Thomson, D J; Freeman, M R

    2015-11-13

    A universal, torque-mixing method for magnetic resonance spectroscopy is presented. In analogy to resonance detection by magnetic induction, the transverse component of a precessing dipole moment can be measured in sensitive broadband spectroscopy, here using a resonant mechanical torque sensor. Unlike induction, the torque amplitude allows equilibrium magnetic properties to be monitored simultaneously with the spin dynamics. Comprehensive electron spin resonance spectra of a single-crystal, mesoscopic yttrium iron garnet disk at room temperature reveal assisted switching between magnetization states and mode-dependent spin resonance interactions with nanoscale surface imperfections. The rich detail allows analysis of even complex three-dimensional spin textures. The flexibility of microelectromechanical and optomechanical devices combined with broad generality and capabilities of torque-mixing magnetic resonance spectroscopy offers great opportunities for development of integrated devices.

  19. Neuromuscular fatigue following isometric contractions with similar torque time integral.

    PubMed

    Rozand, V; Cattagni, T; Theurel, J; Martin, A; Lepers, R

    2015-01-01

    Torque time integral (TTI) is the combination of intensity and duration of a contraction. The aim of this study was to compare neuromuscular alterations following different isometric sub-maximal contractions of the knee extensor muscles but with similar TTI. Sixteen participants performed 3 sustained contractions at different intensities (25%, 50%, and 75% of Maximal Voluntary Contraction (MVC) torque) with different durations (68.5±33.4 s, 35.1±16.8 s and 24.8±12.9 s, respectively) but similar TTI value. MVC torque, maximal voluntary activation level (VAL), M-wave characteristics and potentiated doublet amplitude were assessed before and immediately after the sustained contractions. EMG activity of the vastus lateralis (VL) and -rectus femoris (RF) muscles was recorded during the sustained contractions. MVC torque reduction was similar in the 3 conditions after the exercise (-23.4±2.7%). VAL decreased significantly in a similar extent (-3.1±1.3%) after the 3 sustained contractions. Potentiated doublet amplitude was similarly reduced in the 3 conditions (-19.7±1.5%), but VL and RF M-wave amplitudes remained unchanged. EMG activity of VL and RF muscles increased in the same extent during the 3 contractions (VL: 54.5±40.4%; RF: 53.1±48.7%). These results suggest that central and peripheral alterations accounting for muscle fatigue are similar following isometric contractions with similar TTI. TTI should be considered in the exploration of muscle fatigue during sustained isometric contractions.

  20. A proposed 30-45 minute 4 page standard protocol to evaluate rheumatoid arthritis (SPERA) that includes measures of inflammatory activity, joint damage, and longterm outcomes.

    PubMed

    Pincus, T; Brooks, R H; Callahan, L F

    1999-02-01

    A proposed 4 page, 30-45 minute standard protocol to assess rheumatoid arthritis (SPERA) is described that includes all relevant measures of inflammatory activity such as joint swelling, measures of joint damage such as joint deformity, and outcomes such as joint replacement surgery, to monitor patients in longterm observational studies. Forms are included: (1) a patient self-report modified health assessment questionnaire (MHAQ) to assess function, pain, fatigue, psychological distress, symptoms, and drugs used; (2) assessor-completed forms: "RA clinical features" --criteria for RA, functional class, family history, extraarticular disease, comorbidities, joint surgery, radiographic score, and laboratory findings. (3) A 32 joint count with 5 variables: (a) a "shorthand" normal/abnormal so that normal joints require no further detailed assessment; (b) tenderness or pain on motion; (c) swelling; (d) limited motion or deformity; (e) previous surgeries; physical measures of function, i.e., grip strength, walk time, and button test. (4) Medication review of previous disease modifying antirheumatic drugs (DMARD), work history, and years of education. The forms allow cost effective acquisition of all relevant measures of activity, damage, and outcomes in routine clinical care, and allow recognition that measures of activity may show similar or improved values over 5-10 years, while measures of damage and outcomes indicate severe progression in the same patients. The SPERA is feasible to acquire most known relevant measures of activity, damage, and outcomes in RA in 30-45 min in usual clinical settings, to provide a complete database for analyses of longterm outcomes.

  1. Torque-mixing Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Losby, Joseph; Fani Sani, Fatemeh; Grandmont, Dylan; Diao, Zhu; Belov, Miro; Burgess, Jacob; Compton, Shawn; Hiebert, Wayne; Vick, Doug; Mohammad, Kaveh; Salimi, Elham; Bridges, Gregory; Thomson, Douglas; Freeman, Mark

    A universal, mechanical torque method for magnetic resonance spectroscopy is presented. In analogy to resonance detection by induction, a signal proportional to the transverse component of a precessing dipole moment can be measured as a pure mechanical torque in broadband, frequency-swept spectroscopy. Comprehensive electron spin resonance of a single-crystal, mesoscopic yttrium iron garnet disk at room temperature are presented to demonstrate the method. The rich detail allows analysis of even complex 3D spin textures.

  2. Mandibular lip bumper for molar torque control.

    PubMed

    Celentano, Giuseppe; Longobardi, Annalisa; Cannavale, Rosangela; Perillo, Letizia

    2011-01-01

    Treatment effects of lip bumpers alone include flaring of the mandibular incisors, distalization and uprighting of the mandibular first molars, and buccal expansion of the canines, premolars, and molar. Lip forces are transmitted through this appliance onto the molars. Moreover the lip bumper is able to derotate, expand or constrict, upright and reinforce the anchorage whereas torque control is lacking. Aim of this paper is the presentation of a new type of lip bumper that allows the molar torque control.

  3. Large amplitude oscillation of magnetization in spin-torque oscillator stabilized by field-like torque

    SciTech Connect

    Taniguchi, Tomohiro Kubota, Hitoshi; Imamura, Hiroshi; Tsunegi, Sumito

    2015-05-07

    Oscillation frequency of spin torque oscillator with a perpendicularly magnetized free layer and an in-plane magnetized pinned layer is theoretically investigated by taking into account the field-like torque. It is shown that the field-like torque plays an important role in finding the balance between the energy supplied by the spin torque and the dissipation due to the damping, which results in a steady precession. The validity of the developed theory is confirmed by performing numerical simulations based on the Landau-Lifshitz-Gilbert equation.

  4. 14 CFR 23.397 - Limit control forces and -torques.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit control forces and -torques. 23.397... Control Surface and System Loads § 23.397 Limit control forces and -torques. (a) In the control surface... limit pilot forces and torques are as follows: Control Maximum forces or torques for design...

  5. Torque and Learning and Behavior Problems in Children.

    ERIC Educational Resources Information Center

    Zendel, Ivan H.; Pihl, R. O.

    1980-01-01

    Findings indicate minimal differences, on diagnostic tests, between children who exhibited torque and those who did not. Torque is defined as the circling of any X in a clockwise direction. Torque is not associated with learning problems in school. Diagnostic utility of torque should be carefully considered. (Author)

  6. 14 CFR 23.397 - Limit control forces and -torques.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Limit control forces and -torques. 23.397... Control Surface and System Loads § 23.397 Limit control forces and -torques. (a) In the control surface... limit pilot forces and torques are as follows: Control Maximum forces or torques for design...

  7. 14 CFR 23.397 - Limit control forces and -torques.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Limit control forces and -torques. 23.397... Control Surface and System Loads § 23.397 Limit control forces and -torques. (a) In the control surface... limit pilot forces and torques are as follows: Control Maximum forces or torques for design...

  8. Fourth-order acoustic torque in intense sound fields

    NASA Technical Reports Server (NTRS)

    Wang, T. G.; Kanber, H.; Olli, E. E.

    1978-01-01

    The observation of a fourth-order acoustic torque in intense sound fields is reported. The torque was determined by measuring the acoustically induced angular deflection of a polished cylinder suspended by a torsion fiber. This torque was measured in a sound field of amplitude greater than that in which first-order acoustic torque has been observed.

  9. Evaluating quality of adhesive joints in glass-fiber plastic piping by using active thermal NDT

    NASA Astrophysics Data System (ADS)

    Grosso, M.; Marinho, C. A.; Nesteruk, D. A.; Rebello, J. M.; Soares, S. D.; Vavilov, V. P.

    2013-05-01

    GRP-type composites (Glass-fibre Reinforced Plastics) have been continuously employed in the oil industry in recent years, often on platforms, especially in pipes for water or oil under moderate temperatures. In this case, the pipes are usually connected through adhesive joints and, consequently, the detection of defects in these joints, as areas without adhesive or adhesive failure (disbonding), gains great importance. One-sided inspection on the joint surface (front side) is a challenging task because the material thickness easily exceeds 10 mm that is far beyond the limits of the capacity of thermography applied to GRP inspection, as confirmed by the experience. Detection limits have been evaluated both theoretically and experimentally as a function of outer wall thickness and defect lateral size. The 3D modeling was accomplished by using the ThermoCalc-6L software. The experimental unit consisted of a FLIR SC640 and NEC TH- 9100 IR imagers and some home-made heaters with the power from 1,5 to 30 kW. The results obtained by applying pulsed heating have demonstrated that the inspection efficiency is strongly dependent on the outer wall thickness with a value of about 8 mm being a detection limit.

  10. Laser-induced torques in metallic ferromagnets

    NASA Astrophysics Data System (ADS)

    Freimuth, Frank; Blügel, Stefan; Mokrousov, Yuriy

    2016-10-01

    We study laser-induced torques in bcc Fe, hcp Co, and L 10 FePt based on first-principles electronic structure calculations and the Keldysh nonequilibrium formalism. We find that the torques have two contributions, one from the inverse Faraday effect (IFE) and one from the optical spin-transfer torque (OSTT). Depending on the ferromagnet at hand and on the quasiparticle broadening the two contributions may be of similar magnitude, or one contribution may dominate over the other. Additionally, we determine the nonequilibrium spin polarization in order to investigate its relation to the torque. We find the torques and the perpendicular component of the nonequilibrium spin polarization to be odd in the helicity of the laser light, while the spin polarization that is induced parallel to the magnetization is helicity independent. The parallel component of the nonequilibrium spin polarization is orders of magnitude larger than the perpendicular component. In the case of hcp Co we find good agreement between the calculated laser-induced torque and a recent experiment.

  11. Knudsen torque on heated micro beams

    SciTech Connect

    Li, Qi; Liang, Tengfei; Ye, Wenjing

    2014-12-09

    Thermally induced mechanical loading has been shown to have significant effects on micro/nano objects immersed in a gas with a non-uniform temperature field. While the majority of existing studies and related applications focus on forces, we investigate the torque, and thus the rotational motion, produced by such a mechanism. Using the asymptotic analysis in the near continuum regime, the Knudsen torque acting on an asymmetrically located uniformly heated microbeam in a cold enclosure is investigated. The existence of a non-zero net torque is demonstrated. In addition, it has been found that by manipulating the system configuration, the rotational direction of the torque can be changed. Two types of rotational motion of the microbeam have been identified: the pendulum motion of a rectangular beam, and the unidirectional rotation of a cylindrical beam. A rotational frequency of 4 rpm can be achieved for the cylindrical beam with a diameter of 3μm at Kn = 0.005. Illustrated by the simulations using the direct simulation of Monte Carlo, the Knudsen torque can be much increased in the transition regime, demonstrating the potential of Knudsen torque serving as a rotation engine for micro/nano objects.

  12. A reactive torque control law for gyroscopically controlled space vehicles

    NASA Technical Reports Server (NTRS)

    Farmer, J. E.

    1973-01-01

    A method of control is developed based on the reactive torques as seen by the individual CMG gimbals. The application of a torque to the gimbal of a CMG rotates the momentum vector and applies a torque to the spacecraft according to well-known laws. The response (rotation) of the vehicle produces a reverse or reaction torque opposing the torque producing the gimbal movement. The reactive torque and the pseudoinverse control schemes are contrasted in order to point out the simplicity of the first method. Simulation was performed only to the extent necessary to prove that reactive torque stabilization and control is feasible.

  13. Force and torque production in static multifinger prehension: biomechanics and control. I. Biomechanics.

    PubMed

    Zatsiorsky, Vladimir M; Gregory, Robert W; Latash, Mark L

    2002-07-01

    We studied the coordinated action of fingers during static tasks involving exertion of force and torque on a handheld object. Subjects were asked to keep a handle with an attachment that allowed for independent change of the suspended load (0.5-2.0 kg) and external torque (0.375-1.5 N m) in a vertical position while applying minimal effort. Normal and shear forces were measured from the thumb; normal forces only were measured from the four fingers. EXPERIMENTAL RESULTS: (1) the thumb shear force increased during supination efforts and decreased during pronation efforts; (2) the total moment of the normal finger forces only counterbalanced approximately 50% of the external torque, hence shear forces accounted for approximately one-half of the total torque exerted on the object; (3) the total normal force increased with external torque, and the total force magnitude did not depend on the torque direction; (4) the forces of the 'peripheral' (index and little) fingers depended mainly on the torque while the forces exerted by the 'central' (middle and ring) fingers depended both on the load and torque; (5) there was a monotonic relationship between the mechanical advantage of a finger (i.e., its moment arm during torque production) and the force produced by that finger; and (6) antagonist finger moments acting opposite to the intended direction of the total moment were always observed - at low torques the antagonist moments were as high as 40-60% of the agonist moments. MODELING: A three-zone model of coordinated finger action is suggested. In the first zone of load/torque combinations, activation of antagonist fingers (i.e., fingers that generate antagonist moments) is necessary to prevent slipping. In the second zone, the activity of agonist fingers is sufficient for preventing slips. In the third zone, the performer has freedom to choose between either activating the antagonist fingers or redistributing activities amongst the agonist fingers. The findings of this

  14. The effect of steam sterilization on the accuracy of spring-style mechanical torque devices for dental implants

    PubMed Central

    Mahshid, Minoo; Saboury, Aboulfazl; Fayaz, Ali; Sadr, Seyed Jalil; Lampert, Friedrich; Mir, Maziar

    2012-01-01

    Background Mechanical torque devices (MTDs) are one of the most commonly recommended devices used to deliver optimal torque to the screw of dental implants. Recently, high variability has been reported about the accuracy of spring-style mechanical torque devices (S-S MTDs). Joint stability and survival rate of fixed implant supported prosthesis depends on the accuracy of these devices. Currently, there is limited information on the steam sterilization influence on the accuracy of MTDs. The purpose of this study was to assess the effect of steam sterilization on the accuracy (±10% of the target torque) of spring-style mechanical torque devices for dental implants. Materials and methods Fifteen new S-S MTDs and their appropriate drivers from three different manufacturers (Nobel Biocare, Straumann [ITI], and Biomet 3i [3i]) were selected. Peak torque of devices (5 in each subgroup) was measured before and after autoclaving using a Tohnichi torque gauge. Descriptive statistical analysis was used and a repeated-measures ANOVA with type of device as a between-subject comparison was performed to assess the difference in accuracy among the three groups of spring-style mechanical torque devices after sterilization. A Bonferroni post hoc test was used to assess pairwise comparisons. Results Before steam sterilization, all the tested devices stayed within 10% of their target values. After 100 sterilization cycles, results didn’t show any significant difference between raw and absolute error values in the Nobel Biocare and ITI devices; however the results demonstrated an increase of error values in the 3i group (P < 0.05). Raw error values increased with a predictable pattern in 3i devices and showed more than a 10% difference from target torque values (maximum difference of 14% from target torque was seen in 17% of peak torque measurements). Conclusion Within the limitation of this study, steam sterilization did not affect the accuracy (±10% of the target torque) of the

  15. Estradiol promotes M1-like macrophage activation through cadherin-11 to aggravate temporomandibular joint inflammation in rats.

    PubMed

    Kou, Xiao-Xing; Li, Chen-Shuang; He, Dan-Qing; Wang, Xue-Dong; Hao, Ting; Meng, Zhen; Zhou, Yan-Heng; Gan, Ye-Hua

    2015-03-15

    Macrophages play a major role in joint inflammation. Estrogen is involved in rheumatoid arthritis and temporomandibular disorders. However, the underlying mechanism is still unclear. This study was done to verify and test how estrogen affects M1/M2-like macrophage polarization and then contributes to joint inflammation. Female rats were ovariectomized and treated with increasing doses of 17β-estradiol for 10 d and then intra-articularly injected with CFA to induce temporomandibular joint (TMJ) inflammation. The polarization of macrophages and expression of cadherin-11 was evaluated at 24 h after the induction of TMJ inflammation and after blocking cadherin-11 or estrogen receptors. NR8383 macrophages were treated with estradiol and TNF-α, with or without blocking cadherin-11 or estrogen receptors, to evaluate the expression of the M1/M2-like macrophage-associated genes. We found that estradiol increased the infiltration of macrophages with a proinflammatory M1-like predominant profile in the synovium of inflamed TMJ. In addition, estradiol dose-dependently upregulated the expressions of the M1-associated proinflammatory factor inducible NO synthase (iNOS) but repressed the expressions of the M2-associated genes IL-10 and arginase in NR8383 macrophages. Furthermore, estradiol mainly promoted cadherin-11 expression in M1-like macrophages of inflamed TMJ. By contrast, blockage of cadherin-11 concurrently reversed estradiol-potentiated M1-like macrophage activation and TMJ inflammation, as well as reversed TNF-α-induced induction of inducible NO synthase and NO in NR8383 macrophages. The blocking of estrogen receptors reversed estradiol-potentiated M1-like macrophage activation and cadherin-11 expression. These results suggested that estradiol could promote M1-like macrophage activation through cadherin-11 to aggravate the acute inflammation of TMJs.

  16. Automated assessment of joint synovitis activity from medical ultrasound and power doppler examinations using image processing and machine learning methods

    PubMed Central

    Ziębiński, Adam

    2016-01-01

    Objectives Rheumatoid arthritis is the most common rheumatic disease with arthritis, and causes substantial functional disability in approximately 50% patients after 10 years. Accurate measurement of the disease activity is crucial to provide an adequate treatment and care to the patients. The aim of this study is focused on a computer aided diagnostic system that supports an assessment of synovitis severity. Material and methods This paper focus on a computer aided diagnostic system that was developed within joint Polish–Norwegian research project related to the automated assessment of the severity of synovitis. Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Synovitis is estimated by ultrasound examiner using the scoring system graded from 0 to 3. Activity score is estimated on the basis of the examiner’s experience or standardized ultrasound atlases. The method needs trained medical personnel and the result can be affected by a human error. Results The porotype of a computer-aided diagnostic system and algorithms essential for an analysis of ultrasonic images of finger joints are main scientific output of the MEDUSA project. Medusa Evaluation System prototype uses bone, skin, joint and synovitis area detectors for mutual structural model based evaluation of synovitis. Finally, several algorithms that support the semi-automatic or automatic detection of the bone region were prepared as well as a system that uses the statistical data processing approach in order to automatically localize the regions of interest. Conclusions Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Activity score is estimated on the basis of the examiner’s experience and the result can be affected by a human error. In this paper we presented the MEDUSA project which is focused on a computer aided diagnostic system that supports an assessment of synovitis severity

  17. Modeling, design, and optimization of Mindwalker series elastic joint.

    PubMed

    Wang, Shiqian; Meijneke, Cor; van der Kooij, Herman

    2013-06-01

    Weight and power autonomy are limiting the daily use of wearable exoskeleton. Lightweight, efficient and powerful actuation system are not easy to achieve. Choosing the right combinations of existing technologies, such as battery, gear and motor is not a trivial task. In this paper, we propose an optimization framework by setting up a power-based quasi-static model of the exoskeleton joint drivetrain. The goal is to find the most efficient and lightweight combinations. This framework can be generalized for other similar applications by extending or accommodating the model to their own needs. We also present the Mindwalker exoskeleton joint, for which a novel series elastic actuator, consisting of a ballscrew-driven linear actuator and a double spiral spring, was developed and tested. This linear actuator is capable of outputting 960 W power and the exoskeleton joint can output 100 Nm peak torque continuously. The double spiral spring can sense torque between 0.08Nm and 100 Nm and it exhibits linearity of 99.99%, with no backlash or hysteresis. The series elastic joint can track a chirp torque profile with amplitude of 100 Nm over 6 Hz (large torque bandwidth) and for small torque (2 Nm peak-to-peak), it has a bandwidth over 38 Hz. The integrated exoskeleton joint, including the ballscrew-driven linear actuator, the series spring, electronics and the metal housing which hosts these components, weighs 2.9 kg.

  18. Reusable Solid Rocket Motor Nozzle Joint 5 Redesign

    NASA Technical Reports Server (NTRS)

    Lui, R. C.; Stratton, T. C.; LaMont, D. T.

    2003-01-01

    Torque tension testing of a newly designed Reusable Solid Rocket Motor nozzle bolted assembly was successfully completed. Test results showed that the 3-sigma preload variation was as expected at the required input torque level and the preload relaxation were within the engineering limits. A shim installation technique was demonstrated as a simple process to fill a shear lip gap between nozzle housings in the joint region. A new automated torque system was successfully demonstrated in this test. This torque control tool was found to be very precise and accurate. The bolted assembly performance was further evaluated using the Nozzle Structural Test Bed. Both current socket head cap screw and proposed multiphase alloy bolt configurations were tested. Results indicated that joint skip and bolt bending were significantly reduced with the new multiphase alloy bolt design. This paper summarizes all the test results completed to date.

  19. Enhancement of antidepressant-like activity by joint administration of imipramine and magnesium in the forced swim test: Behavioral and pharmacokinetic studies in mice.

    PubMed

    Poleszak, Ewa; Wlaź, Piotr; Szewczyk, Bernadeta; Kedzierska, Ewa; Wyska, Elzbieta; Librowski, Tadeusz; Szymura-Oleksiak, Joanna; Fidecka, Sylwia; Pilc, Andrzej; Nowak, Gabriel

    2005-07-01

    The effect of joint administration of imipramine (IMI) and magnesium (Mg) on antidepressant-like activity was studied in mice using forced swim test (FST). Mg doses ineffective per se (5 and 10 mg/kg) given jointly with IMI also at ineffective doses (10 and 15 mg/kg) resulted in a potent reduction in the immobility time. Since these combined treatments did not influence locomotor activity, the antidepressant-like activity was not due to non-specific behavioral activation. Moreover, we estimated the effect of joint administration of magnesium and IMI in FST on serum and brain magnesium, IMI and its active metabolite desipramine (DMI) concentrations in mice. Swim stress (mice subjected to FST) increased the magnesium concentration in serum and decreased it in the brain compared to naive animals. Moreover administration of IMI increased (normalized) magnesium brain concentration, without influence on the serum level. Joint administration of IMI and magnesium did not influence magnesium (compared with FST) or IMI and DMI (compared with IMI treatment alone) concentrations in both examined tissues. The present data demonstrated an enhancement of the antidepressant-like effect by joint administration of IMI and magnesium in the FST, and further indicate the particular role of magnesium in the antidepressant action. Since there was no increase in IMI, DMI or magnesium concentration after joint administration of magnesium and IMI, the data suggest that pharmacodynamic rather than pharmacokinetic interaction between magnesium and IMI is accountable for behavioral effect in the FST.

  20. Antibacterial activity of joint fluid in cemented total-knee arthroplasty: an in vivo comparative study of polymethylmethacrylate with and without antibiotic loading.

    PubMed

    Ueng, Steve W N; Hsieh, Pang-Hsin; Shih, Hsin-Nung; Chan, Yi-Shan; Lee, Mel S; Chang, Yuhan

    2012-11-01

    The objective of this study was to evaluate the antibacterial activities of joint fluids of patients undergoing total-knee arthroplasty (TKA). Thirty patients who were scheduled for primary cemented TKA were enrolled in the study. The patients were grouped on the basis of whether the cement was without antibiotic loading (control group) or loaded with oxacillin (oxacillin group) or vancomycin (vancomycin group). Cefazolin was administered to every patient as the perioperative prophylactic antibiotic. Samples of joint fluids were collected from the knee joints at 8, 16, 24, 32, 40, and 48 h after prosthesis implantation. We assessed the bioactivities of the joint fluids against methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA). The antibiotic contents of the joint fluid samples were further evaluated by using high-performance liquid chromatography. Against MSSA, all joint fluid samples exhibited at least 24 h of bacterial inhibition activity. The oxacillin (43.2 h ± 2 h) and vancomycin (40.8 h ± 1.8 h) groups exhibited significantly longer durations of antibacterial activities than the control group (28 h ± 1.3 h; P < 0.05). However, antibacterial activity against MRSA was observed only in the vancomycin group. In conclusion, cefazolin, which was administered as a prophylactic antibiotic in TKA, exhibited good ability for knee joint penetration and was sufficient to inhibit MSSA during its administration. The use of antibiotic-loaded cement can prolong the antibacterial activity of joint fluid in TKA. Further, vancomycin-loaded cement had antibacterial activity against MRSA superior to that of cement loaded with oxacillin or without antibiotic loading.

  1. Ankle Joint Angle and Lower Leg Musculotendinous Unit Responses to Cryotherapy.

    PubMed

    Akehi, Kazuma; Long, Blaine C; Warren, Aric J; Goad, Carla L

    2016-09-01

    Akehi, K, Long, BC, Warren, AJ, and Goad, CL. Ankle joint angle and lower leg musculotendinous unit responses to cryotherapy. J Strength Cond Res 30(9): 2482-2492, 2016-The use of cold application has been debated for its influence on joint range of motion (ROM) and stiffness. The purpose of this study was to determine whether a 30-minute ice bag application to the plantarflexor muscles or ankle influences passive ankle dorsiflexion ROM and lower leg musculotendinous stiffness (MTS). Thirty-five recreationally active college-aged individuals with no history of lower leg injury 6 months before data collection volunteered. On each testing day, we measured maximum passive ankle dorsiflexion ROM (°) and plantarflexor torque (N·m) on an isokinetic dynamometer to calculate the passive plantarflexor MTS (N·m per degree) at 4 joint angles before, during, and after a treatment. Surface electromyography amplitudes (μV), and skin surface and ambient air temperature (°C) were also measured. Subjects received an ice bag to the posterior lower leg, ankle joint, or nothing for 30 minutes in different days. Ice bag application to the lower leg and ankle did not influence passive ROM (F(12,396) = 0.67, p = 0.78). Passive torque increased after ice bag application to the lower leg (F(12,396) = 2.21, p = 0.011). Passive MTS at the initial joint angle increased after ice bag application to the lower leg (F(12,396) = 2.14, p = 0.014) but not at the other joint angles (p > 0.05). Surface electromyography amplitudes for gastrocnemius and soleus muscles increased after ice application to the lower leg (F(2,66) = 5.61, p = 0.006; F(12,396) = 3.60, p < 0.001). Ice bag application to the lower leg and ankle joint does not alter passive dorsiflexion ROM but increases passive ankle plantarflexor torque in addition to passive ankle plantarflexor MTS at the initial joint angle.

  2. Torque equilibrium attitudes for the Space Station

    NASA Technical Reports Server (NTRS)

    Thompson, Roger C.

    1993-01-01

    All spacecraft orbiting in a low earth orbit (LEO) experience external torques due to environmental effects. Examples of these torques include those induced by aerodynamic, gravity-gradient, and solar forces. It is the gravity-gradient and aerodynamic torques that produce the greatest disturbances to the attitude of a spacecraft in LEO, and large asymmetric spacecraft, such as the space station, are affected to a greater degree because the magnitude of the torques will, in general, be larger in proportion to the moments of inertia. If left unchecked, these torques would cause the attitude of the space station to oscillate in a complex manner and the resulting motion would destroy the micro-gravity environment as well as prohibit the orbiter from docking. The application of control torques will maintain the proper attitude, but the controllers have limited momentum capacity. When any controller reaches its limit, propellant must then be used while the device is reset to a zero or negatively-biased momentum state. Consequently, the rate at which momentum is accumulated is a significant factor in the amount of propellant used and the frequency of resupply necessary to operate the station. A torque profile in which the area curve for a positive torque is not equal to the area under the curve for a negative torque is 'biased,' and the consequent momentum build-up about that axis is defined as secular momentum because it continues to grow with time. Conversely, when the areas are equal, the momentum is cyclic and bounded. A Torque Equilibrium Attitude (TEA) is thus defined as an attitude at which the external torques 'balance' each other as much as possible, and which will result in lower momentum growth in the controllers. Ideally, the positive and negative external moments experienced by a spacecraft at the TEA would exactly cancel each other out and small cyclic control torques would be required only for precise attitude control. Over time, the only momentum build

  3. Torque equilibrium attitudes for the Space Station

    NASA Astrophysics Data System (ADS)

    Thompson, Roger C.

    1993-11-01

    All spacecraft orbiting in a low earth orbit (LEO) experience external torques due to environmental effects. Examples of these torques include those induced by aerodynamic, gravity-gradient, and solar forces. It is the gravity-gradient and aerodynamic torques that produce the greatest disturbances to the attitude of a spacecraft in LEO, and large asymmetric spacecraft, such as the space station, are affected to a greater degree because the magnitude of the torques will, in general, be larger in proportion to the moments of inertia. If left unchecked, these torques would cause the attitude of the space station to oscillate in a complex manner and the resulting motion would destroy the micro-gravity environment as well as prohibit the orbiter from docking. The application of control torques will maintain the proper attitude, but the controllers have limited momentum capacity. When any controller reaches its limit, propellant must then be used while the device is reset to a zero or negatively-biased momentum state. Consequently, the rate at which momentum is accumulated is a significant factor in the amount of propellant used and the frequency of resupply necessary to operate the station. A torque profile in which the area curve for a positive torque is not equal to the area under the curve for a negative torque is 'biased,' and the consequent momentum build-up about that axis is defined as secular momentum because it continues to grow with time. Conversely, when the areas are equal, the momentum is cyclic and bounded. A Torque Equilibrium Attitude (TEA) is thus defined as an attitude at which the external torques 'balance' each other as much as possible, and which will result in lower momentum growth in the controllers. Ideally, the positive and negative external moments experienced by a spacecraft at the TEA would exactly cancel each other out and small cyclic control torques would be required only for precise attitude control. Over time, the only momentum build

  4. [Pathophysiological relevance of peroxisome proliferators activated receptors (PPAR) to joint diseases - the pro and con of agonists].

    PubMed

    Jouzeau, Jean-Yves; Moulin, David; Koufany, Meriem; Sebillaud, Sylvie; Bianchi, Arnaud; Netter, Patrick

    2008-01-01

    Peroxisome proliferators activated receptors (PPAR) are ligand-inducible nuclear transacting factors comprising three subtypes, PPARalpha, PPARbeta/delta and PPARgamma, which play a key role in lipids and glucose homeostasis. All PPAR subtypes have been identified in joint or inflammatory cells and their activation resulted in a transcriptional repression of pro-inflammatory cytokines (IL-1, TNFalpha), early inflammatory genes (NOS(2), COX-2, mPGES-1) or matrix metalloproteases (MMP-1, MMP-13), at least for the gamma subtype. PPAR full agonists were also shown to stimulate IL-1 receptor antagonist (IL-1Ra) production by cytokine-stimulated articular cells in a subtype-dependent manner. These anti-inflammatory and anti-catabolic properties were confirmed in animal models of joint diseases where PPAR agonists reduced synovial inflammation while preventing cartilage destruction or inflammatory bone loss, although many effects required much higher doses than needed to restore insulin sensitivity or to lower circulating lipid levels. However, these promising effects of PPAR full agonists were hampered by their ability to reduce the growth factor-dependent synthesis of extracellular matrix components or to induce chondrocyte apoptosis, by the possible contribution of immunosuppressive properties to their anti-arthritic effects, by the increased adipocyte differentiation secondary to prolonged stimulation of PPARgamma, and by a variable contribution of PPAR subtypes depending on the system. Clinical data are scarce in rheumatoid arthritis (RA) patients whereas thousands of patients worldwilde, treated with PPAR agonists for type 2 diabetes or dyslipidemia, are paradoxically prone to suffer from osteoarthritis (OA). Whereas high dosage of full agonists may expose RA patients to cardiovascular adverse effects, the proof of concept that PPAR agonists have therapeutical relevance to OA may benefit from an epidemiological follow-up of joint lesions in diabetic or

  5. Proprioceptive deficit in individuals with unilateral tearing of the anterior cruciate ligament after active evaluation of the sense of joint position☆☆☆

    PubMed Central

    Cossich, Victor; Mallrich, Frédéric; Titonelli, Victor; de Sousa, Eduardo Branco; Velasques, Bruna; Salles, José Inácio

    2014-01-01

    Objective To ascertain whether the proprioceptive deficit in the sense of joint position continues to be present when patients with a limb presenting a deficient anterior cruciate ligament (ACL) are assessed by testing their active reproduction of joint position, in comparison with the contralateral limb. Methods Twenty patients with unilateral ACL tearing participated in the study. Their active reproduction of joint position in the limb with the deficient ACL and in the healthy contralateral limb was tested. Meta-positions of 20% and 50% of the maximum joint range of motion were used. Proprioceptive performance was determined through the values of the absolute error, variable error and constant error. Results Significant differences in absolute error were found at both of the positions evaluated, and in constant error at 50% of the maximum joint range of motion. Conclusion When evaluated in terms of absolute error, the proprioceptive deficit continues to be present even when an active evaluation of the sense of joint position is made. Consequently, this sense involves activity of both intramuscular and tendon receptors. PMID:26229869

  6. Active ultrasonic joint integrity adjudication for real-time structural health monitoring

    NASA Astrophysics Data System (ADS)

    Clayton, Erik H.; Kennel, Matthew B.; Fasel, Timothy R.; Todd, Michael D.; Stabb, Mark C.; Arritt, Brandon J.

    2008-03-01

    The Operationally Responsive Space (ORS) strategy hinges, in part, on realizing technologies which can facilitate the rapid deployment of satellites. Presently, preflight qualification testing and vehicle integration processes are time consumptive and pose as two significant hurdles which must be overcome to effectively enhance US space asset deployment responsiveness. There is a growing demand for innovative embedded Structural Health Monitoring (SHM) technologies which can be seamlessly incorporated onto payload hardware and function in parallel with satellite construction to mitigate lengthy preflight checkout procedures. In this effort our work is focused on the development of a joint connectivity monitoring algorithm which can detect, locate, and assess preload in bolted joint assemblies. Our technology leverages inexpensive, lightweight, flexible thin-film macro-fiber composite (MFC) sensor/actuators with a novel online, data-driven signal processing algorithm. This algorithm inherently relies upon Chaotic Guided Ultrasonic Waves (CGUW) and a novel cross-prediction error classification technique. The efficacy of the monitoring algorithm is evaluated through a series of numerical simulations and experimentally in two test configurations. We conclude with a discussion surrounding further development of this approach into a commercial product as a real-time flight readiness indicator.

  7. Propeller torque load and propeller shaft torque response correlation during ice-propeller interaction

    NASA Astrophysics Data System (ADS)

    Polić, Dražen; Ehlers, Sören; Æsøy, Vilmar

    2017-01-01

    Ships use propulsion machinery systems to create directional thrust. Sailing in ice-covered waters involves the breaking of ice pieces and their submergence as the ship hull advances. Sometimes, submerged ice pieces interact with the propeller and cause irregular fluctuations of the torque load. As a result, the propeller and engine dynamics become imbalanced, and energy propagates through the propulsion machinery system until equilibrium is reached. In such imbalanced situations, the measured propeller shaft torque response is not equal to the propeller torque. Therefore, in this work, the overall system response is simulated under the ice-related torque load using the Bond graph model. The energy difference between the propeller and propeller shaft is estimated and related to their corresponding mechanical energy. Additionally, the mechanical energy is distributed among modes. Based on the distribution, kinetic and potential energy are important for the correlation between propeller torque and propeller shaft response.

  8. Self-oscillation in spin torque oscillator stabilized by field-like torque

    SciTech Connect

    Taniguchi, Tomohiro; Tsunegi, Sumito; Kubota, Hitoshi; Imamura, Hiroshi

    2014-04-14

    The effect of the field-like torque on the self-oscillation of the magnetization in spin torque oscillator with a perpendicularly magnetized free layer was studied theoretically. A stable self-oscillation at zero field is excited for negative β while the magnetization dynamics stops for β = 0 or β > 0, where β is the ratio between the spin torque and the field-like torque. The reason why only the negative β induces the self-oscillation was explained from the view point of the energy balance between the spin torque and the damping. The oscillation power and frequency for various β were also studied by numerical simulation.

  9. Propeller torque load and propeller shaft torque response correlation during ice-propeller interaction

    NASA Astrophysics Data System (ADS)

    Polić, Dražen; Ehlers, Sören; Æsøy, Vilmar

    2017-03-01

    Ships use propulsion machinery systems to create directional thrust. Sailing in ice-covered waters involves the breaking of ice pieces and their submergence as the ship hull advances. Sometimes, submerged ice pieces interact with the propeller and cause irregular fluctuations of the torque load. As a result, the propeller and engine dynamics become imbalanced, and energy propagates through the propulsion machinery system until equilibrium is reached. In such imbalanced situations, the measured propeller shaft torque response is not equal to the propeller torque. Therefore, in this work, the overall system response is simulated under the ice-related torque load using the Bond graph model. The energy difference between the propeller and propeller shaft is estimated and related to their corresponding mechanical energy. Additionally, the mechanical energy is distributed among modes. Based on the distribution, kinetic and potential energy are important for the correlation between propeller torque and propeller shaft response.

  10. Torque shudder protection device and method

    DOEpatents

    King, Robert D.; De Doncker, Rik W. A. A.; Szczesny, Paul M.

    1997-01-01

    A torque shudder protection device for an induction machine includes a flux command generator for supplying a steady state flux command and a torque shudder detector for supplying a status including a negative status to indicate a lack of torque shudder and a positive status to indicate a presence of torque shudder. A flux adapter uses the steady state flux command and the status to supply a present flux command identical to the steady state flux command for a negative status and different from the steady state flux command for a positive status. A limiter can receive the present flux command, prevent the present flux command from exceeding a predetermined maximum flux command magnitude, and supply the present flux command to a field oriented controller. After determining a critical electrical excitation frequency at which a torque shudder occurs for the induction machine, a flux adjuster can monitor the electrical excitation frequency of the induction machine and adjust a flux command to prevent the monitored electrical excitation frequency from reaching the critical electrical excitation frequency.

  11. Torque shudder protection device and method

    DOEpatents

    King, R.D.; Doncker, R.W.A.A. De.; Szczesny, P.M.

    1997-03-11

    A torque shudder protection device for an induction machine includes a flux command generator for supplying a steady state flux command and a torque shudder detector for supplying a status including a negative status to indicate a lack of torque shudder and a positive status to indicate a presence of torque shudder. A flux adapter uses the steady state flux command and the status to supply a present flux command identical to the steady state flux command for a negative status and different from the steady state flux command for a positive status. A limiter can receive the present flux command, prevent the present flux command from exceeding a predetermined maximum flux command magnitude, and supply the present flux command to a field oriented controller. After determining a critical electrical excitation frequency at which a torque shudder occurs for the induction machine, a flux adjuster can monitor the electrical excitation frequency of the induction machine and adjust a flux command to prevent the monitored electrical excitation frequency from reaching the critical electrical excitation frequency. 5 figs.

  12. Feasibility study for convertible engine torque converter

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The feasibility study has shown that a dump/fill type torque converter has excellent potential for the convertible fan/shaft engine. The torque converter space requirement permits internal housing within the normal flow path of a turbofan engine at acceptable engine weight. The unit permits operating the engine in the turboshaft mode by decoupling the fan. To convert to turbofan mode, the torque converter overdrive capability bring the fan speed up to the power turbine speed to permit engagement of a mechanical lockup device when the shaft speed are synchronized. The conversion to turbofan mode can be made without drop of power turbine speed in less than 10 sec. Total thrust delivered to the aircraft by the proprotor, fan, and engine during tansient can be controlled to prevent loss of air speed or altitude. Heat rejection to the oil is low, and additional oil cooling capacity is not required. The turbofan engine aerodynamic design is basically uncompromised by convertibility and allows proper fan design for quiet and efficient cruise operation. Although the results of the feasibility study are exceedingly encouraging, it must be noted that they are based on extrapolation of limited existing data on torque converters. A component test program with three trial torque converter designs and concurrent computer modeling for fluid flow, stress, and dynamics, updated with test results from each unit, is recommended.

  13. Fast joint detection-estimation of evoked brain activity in event-related FMRI using a variational approach

    PubMed Central

    Chaari, Lotfi; Vincent, Thomas; Forbes, Florence; Dojat, Michel; Ciuciu, Philippe

    2013-01-01

    In standard within-subject analyses of event-related fMRI data, two steps are usually performed separately: detection of brain activity and estimation of the hemodynamic response. Because these two steps are inherently linked, we adopt the so-called region-based Joint Detection-Estimation (JDE) framework that addresses this joint issue using a multivariate inference for detection and estimation. JDE is built by making use of a regional bilinear generative model of the BOLD response and constraining the parameter estimation by physiological priors using temporal and spatial information in a Markovian model. In contrast to previous works that use Markov Chain Monte Carlo (MCMC) techniques to sample the resulting intractable posterior distribution, we recast the JDE into a missing data framework and derive a Variational Expectation-Maximization (VEM) algorithm for its inference. A variational approximation is used to approximate the Markovian model in the unsupervised spatially adaptive JDE inference, which allows automatic fine-tuning of spatial regularization parameters. It provides a new algorithm that exhibits interesting properties in terms of estimation error and computational cost compared to the previously used MCMC-based approach. Experiments on artificial and real data show that VEM-JDE is robust to model mis-specification and provides computational gain while maintaining good performance in terms of activation detection and hemodynamic shape recovery. PMID:23096056

  14. Effects of hip and head position on ankle range of motion, ankle passive torque, and passive gastrocnemius tension.

    PubMed

    Andrade, R J; Lacourpaille, L; Freitas, S R; McNair, P J; Nordez, A

    2016-01-01

    Ankle joint range of motion (ROM) is notably influenced by the position of the hip joint. However, this result remains unexplained. Thus, the aim of this study was to test if the ankle passive torque and gastrocnemius muscle tension are affected by the hip and the head positions. The torque and the muscle shear elastic modulus (measured by elastography to estimate muscle tension) were collected in nine participants during passive ankle dorsiflexions performed in four conditions (by combining hip flexion at 90 or 150°, and head flexed or neutral). Ankle maximum dorsiflexion angle significantly decreased by flexing the hip from 150 to 90° (P < 0.001; mean difference 17.7 ± 2.5°), but no effect of the head position was observed (P > 0.05). Maximal passive torque and shear elastic modulus were higher with the hip flexed at 90° (P < 0.001). During submaximal ROM, no effects of the head and hip positioning (P > 0.05) were found for both torque and shear elastic modulus at a given common ankle angle among conditions. Shifts in maximal ankle angle due to hip angle manipulation are not related neither to changes in passive torque nor tension of the gastrocnemius. Further studies should be addressed to better understand the functional role of peripheral nerves and fasciae in the ankle ROM limits.

  15. The Disease Activity Score (DAS) and the Disease Activity Score using 28 joint counts (DAS28) in the management of rheumatoid arthritis.

    PubMed

    van Riel, Piet L C M; Renskers, Lisanne

    2016-01-01

    In rheumatoid arthritis (RA), disease activity cannot be measured in all individual patients according to a single variable. The Disease Activity Score (DAS) and the DAS28 have been developed to measure disease activity in RA both in daily clinical practice as well as in clinical trials on a group as well as individual level. The DAS/DAS28 is a continuous measure of RA disease activity that combines information from swollen joints, tender joints, acute phase response and general health. The DAS-based EULAR response criteria were primarily developed to be used in clinical trials. The EULAR response criteria classify individual patients as non-, moderate, or good responders, dependent on the magnitude of change and level of disease activity reached. In addition, already in the early nineties, cut points were developed to categorise patients in remission. The DAS28 is incorporated in several electronic patient records and web-based systems for monitoring purposes in daily clinical practice. In addition to this, it is being used in combination with patient-reported outcome measures (PROMs) to facilitate self-monitoring.

  16. Modulation of the Relationship Between External Knee Adduction Moments and Medial Joint Contact Forces Across Subjects and Activities

    PubMed Central

    Trepczynski, Adam; Kutzner, Ines; Bergmann, Georg; Taylor, William R; Heller, Markus O

    2014-01-01

    Objective The external knee adduction moment (EAM) is often considered a surrogate measure of the distribution of loads across the tibiofemoral joint during walking. This study was undertaken to quantify the relationship between the EAM and directly measured medial tibiofemoral contact forces (Fmed) in a sample of subjects across a spectrum of activities. Methods The EAM for 9 patients who underwent total knee replacement was calculated using inverse dynamics analysis, while telemetric implants provided Fmed for multiple repetitions of 10 activities, including walking, stair negotiation, sit-to-stand activities, and squatting. The effects of the factors “subject” and “activity” on the relationships between Fmed and EAM were quantified using mixed-effects regression analyses in terms of the root mean square error (RMSE) and the slope of the regression. Results Across subjects and activities a good correlation between peak EAM and Fmed values was observed, with an overall R2 value of 0.88. However, the slope of the linear regressions varied between subjects by up to a factor of 2. At peak EAM and Fmed, the RMSE of the regression across all subjects was 35% body weight (%BW), while the maximum error was 127 %BW. Conclusion The relationship between EAM and Fmed is generally good but varies considerably across subjects and activities. These findings emphasize the limitation of relying solely on the EAM to infer medial joint loading when excessive directed cocontraction of muscles exists and call for further investigations into the soft tissue–related mechanisms that modulate the internal forces at the knee. PMID:24470261

  17. The duration of the inhibitory effects with static stretching on quadriceps peak torque production.

    PubMed

    Siatras, Theophanis A; Mittas, Vasilios P; Mameletzi, Dimitra N; Vamvakoudis, Eystratios A

    2008-01-01

    Although several studies have investigated the acute effect of static stretching exercises, the duration of exercises that negatively affects performance has not been ascertained. This study was conducted to determine the acute effect of different static stretching durations on quadriceps isometric and isokinetic peak torque production. The 50 participants were randomly allocated into five equivalent sized groups and were asked to perform a stretching exercise of different duration (no stretch, 10-second stretch, 20-second stretch, 30-second stretch, and 60-second stretch). The knee flexion range of motion and the isometric and concentric isokinetic peak torques of the quadriceps were measured before and after a static stretching exercise in the four experimental groups. The same parameters were examined in the control group (no stretch) without stretching, before and after a 5-minute passive rest. There were no significant differences among groups before the experimentation regarding their physical characteristics and performances (P > 0.05). These results reflect the different groups' homogeneity. Significant knee joint flexibility increases (P < 0.001) and significant isometric and isokinetic peak torque reductions (P < 0.05-0.001) have been shown to occur only after 30 and 60 seconds of quadriceps static stretching. Stretching reduced isometric peak torque by 8.5% and 16.0%, respectively. Concerning isokinetic peak torque after 30 and 60 seconds of stretching, it was reduced by 5.5% vs. 11.6% at 60 degrees/s and by 5.8% vs. 10.0% at 180 degrees/s. We suggest that torque decrements are related to changes of muscle neuromechanical properties. It is recommended that static stretching exercises of a muscle group for more than 30 seconds of duration be avoided before performances requiring maximal strength.

  18. Joint analysis of infrasound and seismic signals by cross wavelet transform: detection of Mt. Etna explosive activity

    NASA Astrophysics Data System (ADS)

    Cannata, A.; Montalto, P.; Patanè, D.

    2013-06-01

    The prompt detection of explosive volcanic activity is crucial since this kind of activity can release copious amounts of volcanic ash and gases into the atmosphere, causing severe dangers to aviation. In this work, we show how the joint analysis of seismic and infrasonic data by wavelet transform coherence (WTC) can be useful to detect explosive activity, significantly enhancing its recognition that is normally done by video cameras and thermal sensors. Indeed, the efficiency of these sensors can be reduced (or inhibited) in the case of poor visibility due to clouds or gas plumes. In particular, we calculated the root mean square (RMS) of seismic and infrasonic signals recorded at Mt. Etna during 2011. This interval was characterised by several episodes of lava fountains, accompanied by lava effusion, and minor strombolian activities. WTC analysis showed significantly high values of coherence between seismic and infrasonic RMS during explosive activity, with infrasonic and seismic series in phase with each other, hence proving to be sensitive to both weak and strong explosive activity. The WTC capability of automatically detecting explosive activity was compared with the potential of detection methods based on fixed thresholds of seismic and infrasonic RMS. Finally, we also calculated the cross correlation function between seismic and infrasonic signals, which showed that the wave types causing such seismo-acoustic relationship are mainly incident seismic and infrasonic waves, likely with a common source.

  19. Muscle shear elastic modulus is linearly related to muscle torque over the entire range of isometric contraction intensity.

    PubMed

    Ateş, Filiz; Hug, François; Bouillard, Killian; Jubeau, Marc; Frappart, Thomas; Couade, Mathieu; Bercoff, Jeremy; Nordez, Antoine

    2015-08-01

    Muscle shear elastic modulus is linearly related to muscle torque during low-level contractions (<60% of Maximal Voluntary Contraction, MVC). This measurement can therefore be used to estimate changes in individual muscle force. However, it is not known if this relationship remains valid for higher intensities. The aim of this study was to determine: (i) the relationship between muscle shear elastic modulus and muscle torque over the entire range of isometric contraction and (ii) the influence of the size of the region of interest (ROI) used to average the shear modulus value. Ten healthy males performed two incremental isometric little finger abductions. The joint torque produced by Abductor Digiti Minimi was considered as an index of muscle torque and elastic modulus. A high coefficient of determination (R(2)) (range: 0.86-0.98) indicated that the relationship between elastic modulus and torque can be accurately modeled by a linear regression over the entire range (0% to 100% of MVC). The changes in shear elastic modulus as a function of torque were highly repeatable. Lower R(2) values (0.89±0.13 for 1/16 of ROI) and significantly increased absolute errors were observed when the shear elastic modulus was averaged over smaller ROI, half, 1/4 and 1/16 of the full ROI) than the full ROI (mean size: 1.18±0.24cm(2)). It suggests that the ROI should be as large as possible for accurate measurement of muscle shear modulus.

  20. Enhanced physiological tremor deteriorates plantar flexor torque steadiness after bed rest.

    PubMed

    Mulder, Edwin R; Horstman, Astrid M; Gerrits, Karin; Massa, Mark; Kleine, Bert U; de Haan, Arnold; Belavý, Daniel L; Felsenberg, Dieter; Zwarts, Machiel; Stegeman, Dick F

    2011-04-01

    This study evaluated the effectiveness of resistance training to preserve submaximal plantar flexor (PF) torque steadiness following 60 days of bed rest (BR). Twenty-two healthy male subjects underwent either BR only (CTR, n=8), or BR plus resistance training (RT, n=14). The magnitude of torque fluctuations during steady submaximal isometric PF contractions (20%, 40%, 60% and 80% of maximum) were assessed before and after BR. Across contraction intensities, torque fluctuations (coefficient of variation, CV) increased more (P<0.05) after BR for CTR (from 0.31±0.10 to 0.92±0.63; P<0.001), than for RT (from 0.30±0.09 to 0.54±0.27; P<0.01). A shift in the spectral content of torque fluctuations towards increased rhythmic activity between 6.5 and 20Hz was observed in CTR only (P<0.05). H-reflex amplitude (H(max)/M(max) ratio) declined across groups from 0.57±0.18 before BR to 0.44±0.14 following BR (P<0.01) without correlation to CV. The present study showed that increased torque fluctuation after BR resulted from enhanced physiological tremor. Resistance training prevented the spectral shift in isometric PF torque fluctuation and offset ∼50% of the decline in performance associated with long-term BR.

  1. Variable Torque Prescription: State of Art.

    PubMed Central

    Lacarbonara, Mariano; Accivile, Ettore; Abed, Maria R.; Dinoi, Maria Teresa; Monaco, Annalisa; Marzo, Giuseppe; Capogreco, Mario

    2015-01-01

    The variable prescription is widely described under the clinical aspect: the clinics is the result of the evolution of the state-of-the-art, aspect that is less considered in the daily literature. The state-of-the-art is the key to understand not only how we reach where we are but also to learn how to manage propely the torque, focusing on the technical and biomechanical purpos-es that led to the change of the torque values over time. The aim of this study is to update the clinicians on the aspects that affect the torque under the biomechanical sight, helping them to understand how to managing it, following the “timeline changes” in the different techniques so that the Variable Prescription Orthodontic (VPO) would be a suitable tool in every clinical case. PMID:25674173

  2. Thomas precession: Where is the torque

    SciTech Connect

    Muller, R.A. )

    1992-04-01

    Special relativity appears to violate the conservation of angular momentum {bold L} since it predicts that an accelerated gyroscope will precess, i.e., {bold L} will change in the absence of any applied torque. The paradox is resolved in a simple example by demonstrating that there is a torque present. The mass distribution in the gyroscope undergoes a relativistic distortion, and the center of mass is displaced away from the position of the accelerating force. The resulting torque {tau}={ital d}{bold L}/{ital dt}. The model also shows the physical origins of spin-orbit coupling and of the oscillating term.'' A related calculation shows why a moving magnetic dipole has an {ital electric} dipole moment.

  3. RFID Torque Sensing Tag System for Fasteners

    NASA Technical Reports Server (NTRS)

    Fink, Patrick W. (Inventor); Lin, Gregory Y. (Inventor); Ngo, Phong H. (Inventor); Kennedy, Timothy F. (Inventor)

    2016-01-01

    The present invention provides an RFID-based torque sensor that can be used to quickly monitor off the shelf fasteners including fasteners that are used in expensive satellites or other uses where fastener failure can be very costly. In one embodiment, an antenna, RFID ring and spring comprise a sensor tag that can be interrogated with an interrogation signal produced by an interrogator device. When sufficient torque is applied to the fastener, an RFID circuit is connected, and produces a radio frequency (RF) signal that can be read by the interrogator. In one embodiment, the RFID circuit does not transmit when the spring member is not compressed, thereby indicating insufficient tensioning of the fastener. The present invention offers the ability to remotely, quickly, and inexpensively verify that any number of fasteners are torqued properly upon initial installation. Where applicable, the present invention allows low cost monitoring over the life of the fastener.

  4. Torque for an Inertial Piezoelectric Rotary Motor

    PubMed Central

    Xing, Jichun

    2013-01-01

    For a novel inertial piezoelectric rotary motor, the equation of the strain energy in the piezoceramic bimorph and the equations of the strain energy and the kinetic energy in the rotor are given. Based on them, the dynamic equation of the motor is obtained. Using these equations, the inertial driving torque of the motor is investigated. The results show that the impulsive driving torque changes with changing peak voltage of the excitation signal, the piezoelectric stress constant, the thickness of the piezoceramic bimorph, and the rotor radius obviously. Tests about the motor torque are completed which verifies the theory analysis here in. The results can be used to design the operating performance of the motor. PMID:24470794

  5. Objective measures of joint stiffness.

    PubMed

    Roberson, L; Giurintano, D J

    1995-01-01

    Objective measures of joint stiffness allow for the evaluation of the effectiveness of treatment modalities. Without this, the effectiveness of therapy is not quantifiable. Presently, joint stiffness can be quantified by either passive range of motion (PROM) measurement or torque range of motion (TqROM) measurement. PROM measurement does not control the force applied, nor does it require that the other joints in the kinematic chain be held fixed. Also, it demonstrates poor interrater reliability. An idealized device melding existing technologies of constant passive motion devices and computerized workstations is proposed to allow for easier measurement of TqROM angles for analysis data for the determination of the effectiveness of treatment modalities.

  6. Atmospheric Gravitational Torque Variations Based on Various Gravity Fields

    NASA Technical Reports Server (NTRS)

    Sanchez, Braulio V.; Rowlands, David; Smith, David E. (Technical Monitor)

    2001-01-01

    Advancements in the study of the Earth's variable rate of rotation and the motion of its rotation axis have given impetus to the analysis of the torques between the atmosphere, oceans and solid Earth. The output from global general circulation models of the atmosphere (pressure, surface stress) is being used as input to the torque computations. Gravitational torque between the atmosphere, oceans and solid Earth is an important component of the torque budget. Computation of the gravitational torque involves the adoption of a gravitational model from a wide variety available. The purpose of this investigation is to ascertain to what extent this choice might influence the results of gravitational torque computations.

  7. Trunk muscle activation and associated lumbar spine joint shear forces under different levels of external forward force applied to the trunk.

    PubMed

    Kingma, Idsart; Staudenmann, Didier; van Dieën, Jaap H

    2007-02-01

    High anterior intervertebral shear loads could cause low back injuries and therefore the neuromuscular system may actively counteract these forces. This study investigated whether, under constant moment loading relative to L3L4, an increased externally applied forward force on the trunk results in a shift in muscle activation towards the use of muscles with more backward directed lines of action, thereby reducing the increase in total joint shear force. Twelve participants isometrically resisted forward forces, applied at several locations on the trunk, while moments were held constant relative to L3L4. Surface EMG and lumbar curvature were measured, and an EMG-driven muscle model was used to calculate compression and shear forces at all lumbar intervertebral joints. Larger externally applied forward forces resulted in a flattening of the lumbar lordosis and a slightly more backward directed muscle force. Furthermore, the overall muscle activation increased. At the T12L1 to L3L4 joint, resulting joint shear forces remained small (less than 200N) because the average muscle force pulled backward relative to those joints. However, at the L5S1 joint the average muscle force pulled the trunk forward so that the increase in muscle force with increasing externally applied forward force caused a further rise in shear force (by 102.1N, SD=104.0N), resulting in a joint shear force of 1080.1N (SD=150.4N) at 50Nm moment loading. It is concluded that the response of the neuromuscular system to shear force challenges tends to increase rather than reduce the shear loading at the lumbar joint that is subjected to the highest shear forces.

  8. Initial torque stability of a new bone condensing dental implant. A cohort study of 140 consecutively placed implants.

    PubMed

    Irinakis, Tassos; Wiebe, Colin

    2009-01-01

    The aim of this paper was to determine the torque resistance of this new implant during placement in different types of bone, immediate placement into sockets, and in grafted bone. The torque at time of placement serves as an indication of initial stability, which is accepted as an important factor for implant osseointegration and immediate loading. Within a 13-month period, 140 NobelActive implants in 84 consecutive patients were placed into types I-IV bone in fresh sockets, and into grafted bone (both in maxillary sinuses and on the facial alveolar surfaces where bone had been lost). The final torque was measured with a manual torque control wrench as manufactured by Nobel Biocare for clinical use with this type of implant. One hundred forty implants with 3.5 to 5 mm diameters and 10 to 15 mm lengths were placed in different types of bone, either as delayed or immediate implants into fresh extraction sockets. These implants demonstrated a mean torque stability value of 50.8 Ncm. The average insertion torque for delayed implants was 49.7 Ncm. For immediate implants the average torque was 52.6 Ncm. Placement into soft bone was also favorable at an average of 47.9 Ncm. Typical straight walled and tapered implants generally exhibit 10 to 35 Ncm insertion torques. The NobelActive implant consistently reaches higher torque levels. This may indicate they are more favorably suited to early provisionalization and loading. Soft bone (type IV) did not seem to decrease significantly the torque of insertion of these implants. Further longer term studies are needed to investigate whether this indeed makes these implants more suited for early provisionalization and loading than traditional root form. Long term studies are also needed to investigate maintenance of bone levels surrounding these implants.

  9. LOW ACTIVATION JOINING OF SIC/SIC COMPOSITES FOR FUSION APPLICATIONS: MODELING DUAL-PHASE MICROSTRUCTURES AND DISSIMILAR MATERIAL JOINTS

    SciTech Connect

    Henager, Charles H.; Nguyen, Ba Nghiep; Kurtz, Richard J.; Ferraris, M.; Katoh, Y.

    2016-03-31

    Finite element continuum damage models (FE-CDM) have been developed to simulate and model dual-phase joints and cracked joints for improved analysis of SiC materials in nuclear environments. This report extends the analysis from the last reporting cycle by including results from dual-phase models and from cracked joint models.

  10. The Challenge of Limiting Greenhouse Gas Emissions Through Activities implemented Jointly in Developing Countries: A Brazilian Perspective

    SciTech Connect

    La Rovere, E.L.

    1998-11-01

    This paper addresses, from the Brazilian perspective, the main problems with Joint Implementation/Activities Implemented Jointly (JI/AIJ) between industrialized (Annex I) and developing (non-Annex I) countries, as defined by the United Nations Framework Convention on Climate Change (UNFCCC). Four possible GHG emissions abatement measures are presented for Brazil: forest protection, reforestation projects for carbon sequestration or charcoal manufacturing, use of ethanol produced from sugar cane as a car fuel, and electrical energy conservation through an increase in end-use efficiencies. These four case studies form the basis of a discussion regarding the validity of developing countries' concerns about JI/AIJ. Recommendations are offered for overcoming the present shortcomings of JI/AIJ in developing countries. The primary conclusion is that Annex I countries' funding of JI/AIJ projects in developing countries in return for GHG emissions credits is not the best means to implement the UNFCCC. However, JI/AIJ projects can be a productive means of preventing global climate change if combined with other measures, including GHG emissions reduction targets for all countries involved in JI/AIJ projects and limits on the percentage of industrialized countries' emissions reductions that can be met through projects in developing countries.

  11. Torque limit of PM motors for field-weakening region operation

    SciTech Connect

    Royak, Semyon; Harbaugh, Mark M

    2012-02-14

    The invention includes a motor controller and technique for controlling a permanent magnet motor. In accordance with one aspect of the present technique, a permanent magnet motor is controlled by receiving a torque command, determining a physical torque limit based on a stator frequency, determining a theoretical torque limit based on a maximum available voltage and motor inductance ratio, and limiting the torque command to the smaller of the physical torque limit and the theoretical torque limit. Receiving the torque command may include normalizing the torque command to obtain a normalized torque command, determining the physical torque limit may include determining a normalized physical torque limit, determining a theoretical torque limit may include determining a normalized theoretical torque limit, and limiting the torque command may include limiting the normalized torque command to the smaller of the normalized physical torque limit and the normalized theoretical torque limit.

  12. Quadriceps Strength Asymmetry Following ACL Reconstruction Alters Knee Joint Biomechanics and Functional Performance at Time of Return to Activity

    PubMed Central

    Palmieri-Smith, RM; Lepley, LK

    2016-01-01

    Background Quadriceps strength deficits are observed clinically following anterior cruciate injury and reconstruction and are often not overcome despite rehabilitation. Given that quadriceps strength may be important for achieving symmetrical joint biomechanics and promoting long-term joint health, determining the magnitude of strength deficits that lead to altered mechanics is critical. Purpose To determine if the magnitude of quadriceps strength asymmetry alters knee and hip biomechanical symmetry, as well as functional performance and self-reported function. Study Design Cross-Sectional study. Methods Seventy-three patients were tested at the time they were cleared for return to activity following ACL reconstruction. Quadriceps strength and activation, scores on the International Knee Documentation Committee form, the hop for distance test, and sagittal plane lower extremity biomechanics were recorded while patients completed a single-legged hop. Results Patients with high and moderate quadriceps strength symmetry had larger central activation ratios as well as greater limb symmetry indices on the hop for distance compared to patients with low quadriceps strength symmetry (P<0.05). Similarly, knee flexion angle and external moment symmetry was higher in the patients with high and moderate quadriceps symmetry compared to those with low symmetry (P<0.05). Quadriceps strength was found to be associated with sagittal plane knee angle and moment symmetry (P<0.05). Conclusion Patients with low quadriceps strength displayed greater movement asymmetries at the knee in the sagittal plane. Quadriceps strength was related to movement asymmetries and functional performance. Rehabilitation following ACL reconstruction needs to focus on maximizing quadriceps strength, which likely will lead to more symmetrical knee biomechanics. PMID:25883169

  13. Joint FAO/WHO/IOC activities to provide scientific advice on marine biotoxins (research report).

    PubMed

    Toyofuku, Hajime

    2006-12-01

    The Joint FAO/WHO/IOC ad hoc Expert Consultation on Biotoxins in Molluscan Bivalves performed risk assessments for a number of biotoxins present in bivalve molluscs. For performing risk assessments, the Expert Consultation categorized the biotoxins into eight distinct groups based on chemical structure. The Expert Consultation established LOAELs for the azaspiracid (AZA), okadaic acid (OA), saxitoxin (STX), and domoic acid (DA) toxin groups. The derived provisional acute RfDs for the AZA, OA, STX, and DA toxin groups were 0.04 microg/kg bw, 0.33 microg/kg bw, 0.7 microg/kg bw, and 100 microg/kg bw, respectively. For the yessotoxin (YTX) group, a NOAEL was established, based on animal studies. Applying a safety factor of 100, a provisional acute RfD of 50 microg/kg bw was suggested for the YTX group. The Expert Consultation considered that the database for cyclic imines, brevetoxins, and pectenotoxins was insufficient to establish provisional acute RfDs for these three toxin groups.

  14. Peak torque and rate of torque development influence on repeated maximal exercise performance: contractile and neural contributions.

    PubMed

    Morel, Baptiste; Rouffet, David M; Saboul, Damien; Rota, Samuel; Clémençon, Michel; Hautier, Christophe A

    2015-01-01

    Rapid force production is critical to improve performance and prevent injuries. However, changes in rate of force/torque development caused by the repetition of maximal contractions have received little attention. The aim of this study was to determine the relative influence of rate of torque development (RTD) and peak torque (T(peak)) on the overall performance (i.e. mean torque, T(mean)) decrease during repeated maximal contractions and to investigate the contribution of contractile and neural mechanisms to the alteration of the various mechanical variables. Eleven well-trained men performed 20 sets of 6-s isokinetic maximal knee extensions at 240° · s(-1), beginning every 30 seconds. RTD, T(peak) and T(mean) as well as the Rate of EMG Rise (RER), peak EMG (EMG(peak)) and mean EMG (EMG(mean)) of the vastus lateralis were monitored for each contraction. A wavelet transform was also performed on raw EMG signal for instant mean frequency (if(mean)) calculation. A neuromuscular testing procedure was carried out before and immediately after the fatiguing protocol including evoked RTD (eRTD) and maximal evoked torque (eT(peak)) induced by high frequency doublet (100 Hz). T(mean) decrease was correlated to RTD and T(peak) decrease (R(²) = 0.62; p<0.001; respectively β=0.62 and β=0.19). RER, eRTD and initial if(mean) (0-225 ms) decreased after 20 sets (respectively -21.1 ± 14.1, -25 ± 13%, and ~20%). RTD decrease was correlated to RER decrease (R(²) = 0.36; p<0.05). The eT(peak) decreased significantly after 20 sets (24 ± 5%; p<0.05) contrary to EMG(peak) (-3.2 ± 19.5 %; p=0.71). Our results show that reductions of RTD explained part of the alterations of the overall performance during repeated moderate velocity maximal exercise. The reductions of RTD were associated to an impairment of the ability of the central nervous system to maximally activate the muscle in the first milliseconds of the contraction.

  15. Peak Torque and Rate of Torque Development Influence on Repeated Maximal Exercise Performance: Contractile and Neural Contributions

    PubMed Central

    Morel, Baptiste; Rouffet, David M.; Saboul, Damien; Rota, Samuel; Clémençon, Michel; Hautier, Christophe A.

    2015-01-01

    Rapid force production is critical to improve performance and prevent injuries. However, changes in rate of force/torque development caused by the repetition of maximal contractions have received little attention. The aim of this study was to determine the relative influence of rate of torque development (RTD) and peak torque (Tpeak) on the overall performance (i.e. mean torque, Tmean) decrease during repeated maximal contractions and to investigate the contribution of contractile and neural mechanisms to the alteration of the various mechanical variables. Eleven well-trained men performed 20 sets of 6-s isokinetic maximal knee extensions at 240°·s-1, beginning every 30 seconds. RTD, Tpeak and Tmean as well as the Rate of EMG Rise (RER), peak EMG (EMGpeak) and mean EMG (EMGmean) of the vastus lateralis were monitored for each contraction. A wavelet transform was also performed on raw EMG signal for instant mean frequency (ifmean) calculation. A neuromuscular testing procedure was carried out before and immediately after the fatiguing protocol including evoked RTD (eRTD) and maximal evoked torque (eTpeak) induced by high frequency doublet (100 Hz). Tmean decrease was correlated to RTD and Tpeak decrease (R²=0.62; p<0.001; respectively β=0.62 and β=0.19). RER, eRTD and initial ifmean (0-225 ms) decreased after 20 sets (respectively -21.1±14.1, -25±13%, and ~20%). RTD decrease was correlated to RER decrease (R²=0.36; p<0.05). The eTpeak decreased significantly after 20 sets (24±5%; p<0.05) contrary to EMGpeak (-3.2±19.5 %; p=0.71). Our results show that reductions of RTD explained part of the alterations of the overall performance during repeated moderate velocity maximal exercise. The reductions of RTD were associated to an impairment of the ability of the central nervous system to maximally activate the muscle in the first milliseconds of the contraction. PMID:25901576

  16. Torque-balanced vibrationless rotary coupling

    DOEpatents

    Miller, Donald M.

    1980-01-01

    This disclosure describes a torque-balanced vibrationless rotary coupling for transmitting rotary motion without unwanted vibration into the spindle of a machine tool. A drive member drives a driven member using flexible connecting loops which are connected tangentially and at diametrically opposite connecting points through a free floating ring.

  17. Torque wrench allows readings from inaccessible locations

    NASA Technical Reports Server (NTRS)

    De Barnardo, M.

    1966-01-01

    Torque wrench with an adjustable drive shaft permits indicator to remain in view when used on sections of equipment with limited access. The shaft is capable of protruding from either side of the wrench head by means of spring loaded balls.

  18. Electric Field Driven Torque in ATP Synthase

    PubMed Central

    Miller, John H.; Rajapakshe, Kimal I.; Infante, Hans L.; Claycomb, James R.

    2013-01-01

    FO-ATP synthase (FO) is a rotary motor that converts potential energy from ions, usually protons, moving from high- to low-potential sides of a membrane into torque and rotary motion. Here we propose a mechanism whereby electric fields emanating from the proton entry and exit channels act on asymmetric charge distributions in the c-ring, due to protonated and deprotonated sites, and drive it to rotate. The model predicts a scaling between time-averaged torque and proton motive force, which can be hindered by mutations that adversely affect the channels. The torque created by the c-ring of FO drives the γ-subunit to rotate within the ATP-producing complex (F1) overcoming, with the aid of thermal fluctuations, an opposing torque that rises and falls with angular position. Using the analogy with thermal Brownian motion of a particle in a tilted washboard potential, we compute ATP production rates vs. proton motive force. The latter shows a minimum, needed to drive ATP production, which scales inversely with the number of proton binding sites on the c-ring. PMID:24040370

  19. Noncontact Measurements Of Torques In Shafts

    NASA Technical Reports Server (NTRS)

    Schwartzbart, Aaron

    1991-01-01

    Additional information extracted from eddy-current proximeter. Positioned over rotating shaft, measures both displacement of and torsion in shaft. Torque applied to shaft calculable from output of proximeter. Possible to extract torsion information from existing tape-recorded proximeter data.

  20. Anatomy of a bearing torque problem

    NASA Technical Reports Server (NTRS)

    Phinney, Damon D.

    1987-01-01

    In the early 1970s, an antenna despin drive was developed for MBB solar science satellite HELIOS. A problem with high bearing drag torque that was encountered on the two flight models of this drive, after successful tests were completed on twelve bearings, an engineering model, and the qualification unit is discussed.

  1. Torque-while-turnaround scan mirror assembly

    NASA Technical Reports Server (NTRS)

    Starkus, C. J.

    1977-01-01

    A scan mirror assembly which is part of a thematic mapper system is described with emphasis on mechanical aspects of the design. Features of the oscillating scan mirror mechanism include: a low level of structural vibration for the impact energies involved in mirror oscillation and return of energy lost during impact to the mirror by applying torque during the instant of impact.

  2. Air brake-dynamometer accurately measures torque

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Air brake-dynamometer assembly combines the principles of the air turbine and the air pump to apply braking torque. The assembly absorbs and measures power outputs of rotating machinery over a wide range of shaft speeds. It can also be used as an air turbine.

  3. 14 CFR 23.361 - Engine torque.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... and supporting structure must be designed to withstand each of the following: (1) A limit...

  4. 14 CFR 23.361 - Engine torque.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... and supporting structure must be designed to withstand each of the following: (1) A limit...

  5. 14 CFR 23.361 - Engine torque.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... and supporting structure must be designed to withstand each of the following: (1) A limit...

  6. 14 CFR 23.361 - Engine torque.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... and supporting structure must be designed to withstand each of the following: (1) A limit...

  7. 14 CFR 23.361 - Engine torque.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Flight Loads § 23.361 Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... and supporting structure must be designed to withstand each of the following: (1) A limit...

  8. Muscle co-contraction modulates damping and joint stability in a three-link biomechanical limb.

    PubMed

    Heitmann, Stewart; Ferns, Norm; Breakspear, Michael

    2011-01-01

    Computational models of neuromotor control require forward models of limb movement that can replicate the natural relationships between muscle activation and joint dynamics without the burdens of excessive anatomical detail. We present a model of a three-link biomechanical limb that emphasizes the dynamics of limb movement within a simplified two-dimensional framework. Muscle co-contraction effects were incorporated into the model by flanking each joint with a pair of antagonist muscles that may be activated independently. Muscle co-contraction is known to alter the damping and stiffness of limb joints without altering net joint torque. Idealized muscle actuators were implemented using the Voigt muscle model which incorporates the parallel elasticity of muscle and tendon but omits series elasticity. The natural force-length-velocity relationships of contractile muscle tissue were incorporated into the actuators using ideal mathematical forms. Numerical stability analysis confirmed that co-contraction of these simplified actuators increased damping in the biomechanical limb consistent with observations of human motor control. Dynamic changes in joint stiffness were excluded by the omission of series elasticity. The analysis also revealed the unexpected finding that distinct stable (bistable) equilibrium positions can co-exist under identical levels of muscle co-contraction. We map the conditions under which bistability arises and prove analytically that monostability (equifinality) is guaranteed when the antagonist muscles are identical. Lastly we verify these analytic findings in the full biomechanical limb model.

  9. Muscle Co-Contraction Modulates Damping and Joint Stability in a Three-Link Biomechanical Limb

    PubMed Central

    Heitmann, Stewart; Ferns, Norm; Breakspear, Michael

    2012-01-01

    Computational models of neuromotor control require forward models of limb movement that can replicate the natural relationships between muscle activation and joint dynamics without the burdens of excessive anatomical detail. We present a model of a three-link biomechanical limb that emphasizes the dynamics of limb movement within a simplified two-dimensional framework. Muscle co-contraction effects were incorporated into the model by flanking each joint with a pair of antagonist muscles that may be activated independently. Muscle co-contraction is known to alter the damping and stiffness of limb joints without altering net joint torque. Idealized muscle actuators were implemented using the Voigt muscle model which incorporates the parallel elasticity of muscle and tendon but omits series elasticity. The natural force-length-velocity relationships of contractile muscle tissue were incorporated into the actuators using ideal mathematical forms. Numerical stability analysis confirmed that co-contraction of these simplified actuators increased damping in the biomechanical limb consistent with observations of human motor control. Dynamic changes in joint stiffness were excluded by the omission of series elasticity. The analysis also revealed the unexpected finding that distinct stable (bistable) equilibrium positions can co-exist under identical levels of muscle co-contraction. We map the conditions under which bistability arises and prove analytically that monostability (equifinality) is guaranteed when the antagonist muscles are identical. Lastly we verify these analytic findings in the full biomechanical limb model. PMID:22275897

  10. Active Region Loops: Temperature Measurements as a Function of Time from Joint TRACE and SOHO CDS Observations

    NASA Astrophysics Data System (ADS)

    Cirtain, J. W.; Del Zanna, G.; DeLuca, E. E.; Mason, H. E.; Martens, P. C. H.; Schmelz, J. T.

    2007-01-01

    In this paper, we aim to quantitatively investigate the structure and time variation of quiescent active region loop structures. We coordinated a joint program of observations (JOP 146) using TRACE, to obtain high-cadence EUV images, and SOHO CDS, to obtain spectroscopic data. Loop intensities are used to determine temperature as a function of time for a single loop, taking full account of the background emission. In many locations, the emission measure loci are consistent with an isothermal structure. However, the results indicate significant changes in the loop temperature (between 1 and 2 MK) over the 6 hr observing period. It is possible that the loop structures are composed of multiple, independently heated strands with sizes less than the resolution of the imager and spectrometer.

  11. Active vibration control of Flexible Joint Manipulator using Input Shaping and Adaptive Parameter Auto Disturbance Rejection Controller

    NASA Astrophysics Data System (ADS)

    Li, W. P.; Luo, B.; Huang, H.

    2016-02-01

    This paper presents a vibration control strategy for a two-link Flexible Joint Manipulator (FJM) with a Hexapod Active Manipulator (HAM). A dynamic model of the multi-body, rigid-flexible system composed of an FJM, a HAM and a spacecraft was built. A hybrid controller was proposed by combining the Input Shaping (IS) technique with an Adaptive-Parameter Auto Disturbance Rejection Controller (APADRC). The controller was used to suppress the vibration caused by external disturbances and input motions. Parameters of the APADRC were adaptively adjusted to ensure the characteristic of the closed loop system to be a given reference system, even if the configuration of the manipulator significantly changes during motion. Because precise parameters of the flexible manipulator are not required in the IS system, the operation of the controller was sufficiently robust to accommodate uncertainties in system parameters. Simulations results verified the effectiveness of the HAM scheme and controller in the vibration suppression of FJM during operation.

  12. Plasminogen activation in synovial tissues: differences between normal, osteoarthritis, and rheumatoid arthritis joints

    PubMed Central

    Busso, N.; Peclat, V.; So, A.; Sappino, A.

    1997-01-01

    OBJECTIVE—To analyse the functional activity of the plasminogen activators urokinase (uPA) and tissue type plasminogen activator (tPA) in human synovial membrane, and to compare the pattern of expression between normal, osteoarthritic, and rheumatoid synovium. The molecular mechanisms underlying differences in PA activities between normal and pathological synovial tissues have been further examined.
METHODS—Synovial membranes from seven normal (N) subjects, 14 osteoarthritis (OA), and 10 rheumatoid arthritis (RA) patients were analysed for plasminogen activator activity by conventional zymography and in situ zymography on tissue sections. The tissue distribution of uPA, tPA, uPA receptor (uPAR), and plasminogen activator inhibitor type-1 (PAI-1) was studied by immunohistochemistry. uPA, tPA, uPAR, and PAI-1 mRNA values and mRNA distribution were assessed by northern blot and in situ hybridisations respectively.
RESULTS—All normal and most OA synovial tissues expressed predominantly tPA catalysed proteolytic activity mainly associated to the synovial vasculature. In some OA, tPA activity was expressed together with variable amounts of uPA mediated activity. By contrast, most RA synovial tissues exhibited considerably increased uPA activity over the proliferative lining areas, while tPA activity was reduced when compared with N and OA synovial tissues. This increase in uPA activity was associated with increased levels of uPA antigen and its corresponding mRNA, which were localised over the synovial proliferative lining areas. In addition, in RA tissues, expression of the specific uPA receptor (uPAR) and of the plasminogen activator inhibitor-type 1 (PAI-1) were also increased.
CONCLUSION—Taken together, these results show an alteration of the PA/plasmin system in RA synovial tissues, resulting in increased uPA catalytic activity that may play a part in tissue destruction in RA.

 PMID:9370880

  13. Evaluation of Anatomical and Functional Hip Joint Center Methods: The Effects of Activity Type, Gender, and Proximal Reference Segment.

    PubMed

    McGibbon, C A; Fowler, J; Chase, S; Steeves, K; Landry, J; Mohamed, A

    2016-01-01

    Accurate hip joint center (HJC) location is critical when studying hip joint biomechanics. The HJC is often determined from anatomical methods, but functional methods are becoming increasingly popular. Several studies have examined these methods using simulations and in vivo gait data, but none has studied high-range of motion activities, such a chair rise, nor has HJC prediction been compared between males and females. Furthermore, anterior superior iliac spine (ASIS) marker visibility during chair rise can be problematic, requiring a sacral cluster as an alternative proximal segment; but functional HJC has not been explored using this approach. For this study, the quality of HJC measurement was based on the joint gap error (JGE), which is the difference in global HJC between proximal and distal reference segments. The aims of the present study were to: (1) determine if JGE varies between pelvic and sacral referenced HJC for functional and anatomical methods, (2) investigate which functional calibration motion results in the lowest JGE and if the JGE varies depending on movement type (gait versus chair rise) and gender, and (3) assess whether the functional HJC calibration results in lower JGE than commonly used anatomical approaches and if it varies with movement type and gender. Data were collected on 39 healthy adults (19 males and 20 females) aged 14-50 yr old. Participants performed four hip "calibration" tests (arc, cross, star, and star-arc), as well as gait and chair rise (activities of daily living (ADL)). Two common anatomical methods were used to estimate HJC and were compared to HJC computed using a published functional method with the calibration motions above, when using pelvis or sacral cluster as the proximal reference. For ADL trials, functional methods resulted in lower JGE (12-19 mm) compared to anatomical methods (13-34 mm). It was also found that women had significantly higher JGE compared to men and JGE was significantly higher for

  14. Activation of α2A-adrenergic signal transduction in chondrocytes promotes degenerative remodelling of temporomandibular joint

    PubMed Central

    Jiao, Kai; Zeng, Guang; Niu, Li-Na; Yang, Hong-xu; Ren, Gao-tong; Xu, Xin-yue; Li, Fei-fei; Tay, Franklin R.; Wang, Mei-qing

    2016-01-01

    This study tested whether activation of adrenoreceptors in chondrocytes has roles in degenerative remodelling of temporomandibular joint (TMJ) and to determine associated mechanisms. Unilateral anterior crossbite (UAC) was established to induce TMJ degeneration in rats. Saline vehicle, α2- and β-adrenoreceptor antagonists or agonists were injected locally into the TMJ area of UAC rats. Cartilage degeneration, subchondral bone microarchitecture and the expression of adrenoreceptors, aggrecans, matrix metalloproteinases (MMPs) and RANKL by chondrocytes were evaluated. Chondrocytes were stimulated by norepinephrine to investigate signal transduction of adrenoreceptors. Increased α2A-adrenoreceptor expression was observed in condylar cartilage of UAC rats, together with cartilage degeneration and subchondral bone loss. Norepinephrine depresses aggrecans expression but stimulates MMP-3, MMP-13 and RANKL production by chondrocytes through ERK1/2 and PKA pathway; these effects were abolished by an α2A-adrenoreceptor antagonist. Furthermore, inhibition of α2A-adrenoreceptor attenuated degenerative remodelling in the condylar cartilage and subchondral bone, as revealed by increased cartilage thickness, proteoglycans and aggrecan expression, and decreased MMP-3, MMP-13 and RANKL expressions in cartilage, increased BMD, BV/TV, and decreased Tb.Sp in subchondral bone. Conversely, activation of α2A-adrenoreceptor intensified aforementioned degenerative changes in UAC rats. It is concluded that activation of α2A-adrenergic signal in chondrocytes promotes TMJ degenerative remodelling by chondrocyte-mediated pro-catabolic activities. PMID:27452863

  15. Effect of stretching on agonist-antagonist muscle activity and muscle force output during single and multiple joint isometric contractions.

    PubMed

    McBride, J M; Deane, R; Nimphius, S

    2007-02-01

    Eight moderately active male subjects where tested for peak force in an isometric knee extension test and peak force and rate of force development in an isometric squat test. Both tests where performed at a 100 degrees knee angle and average integrated electromyography (IEMG) was measured from the vastus medialis (VM), vastus lateralis (VL) and biceps femoris (BF) muscles. Subjects performed the two conditions, stretching (S) or control (C) in a randomized order. Subjects where tested for baseline strength measures in both the isometric knee extension and isometric squat and then either stretched or sat quietly for 10 min. Following S or C subjects where then tested at six time points. Following S peak force in the isometric knee extension was significantly (P < or = 0.05) less than C at 1, 2, 8 and 16 min post. No significant difference in peak force was found between S and C in the isometric squat. However, following S the rate of force development in the isometric squat was significantly less than C at immediately post. No significant differences where observed in IEMG of the VM or VL between S and C in either the isometric knee extension or isometric squat. However, IEMG significantly decreased in the BF at 1 min post after S in comparison with C in both the isometric knee extension and isometric squat. Stretching appears to decrease muscle force output in a single joint isometric contraction and rate of force development in a multiple joint isometric contraction. Possible changes in agonist-antagonist muscle activity patterns need to be further examined.

  16. Wear Testing of Moderate Activities of Daily Living Using In Vivo Measured Knee Joint Loading

    PubMed Central

    Reinders, Jörn; Sonntag, Robert; Vot, Leo; Gibney, Christian; Nowack, Moritz; Kretzer, Jan Philippe

    2015-01-01

    Resumption of daily living activities is a basic expectation for patients provided with total knee replacements. However, there is a lack of knowledge regarding the impact of different activities on the wear performance. In this study the wear performance under application of different daily activities has been analyzed. In vivo load data for walking, walking downstairs/upstairs, sitting down/standing up, and cycling (50 W & 120 W) has been standardized for wear testing. Wear testing of each activity was carried out on a knee wear simulator. Additionally, ISO walking was tested for reasons of comparison. Wear was assessed gravimetrically and wear particles were analyzed. In vivo walking produced the highest overall wear rates, which were determined to be three times higher than ISO walking. Moderate wear rates were determined for walking upstairs and downstairs. Low wear rates were determined for standing up/sitting down and cycling at power levels of 50 W and 120 W. The largest wear particles were observed for cycling. Walking based on in vivo data has been shown to be the most wear-relevant activity. Highly demanding activities (stair climbing) produced considerably less wear. Taking into account the expected number of loads, low-impact activities like cycling may have a greater impact on articular wear than highly demanding activities. PMID:25811996

  17. Joint pain

    MedlinePlus

    ... that may be done include: CBC or blood differential C-reactive protein Joint x-ray Sedimentation rate ... chap 256. Schaible H-G. Joint pain: basic mechanisms. In: McMahon SB, Koltzenburg M, Tracey I, Turk ...

  18. The Association of Academic Health Sciences Libraries' legislative activities and the Joint Medical Library Association/Association of Academic Health Sciences Libraries Legislative Task Force

    PubMed Central

    Zenan, Joan S.

    2003-01-01

    The Association of Academic Health Sciences Libraries' (AAHSL's) involvement in national legislative activities and other advocacy initiatives has evolved and matured over the last twenty-five years. Some activities conducted by the Medical Library Association's (MLA's) Legislative Committee from 1976 to 1984 are highlighted to show the evolution of MLA's and AAHSL's interests in collaborating on national legislative issues, which resulted in an agreement to form a joint legislative task force. The history, work, challenges, and accomplishments of the Joint MLA/AAHSL Legislative Task Force, formed in 1985, are discussed. PMID:12883581

  19. Torque decrease during submaximal evoked contractions of the quadriceps muscle is linked not only to muscle fatigue.

    PubMed

    Matkowski, Boris; Lepers, Romuald; Martin, Alain

    2015-05-01

    The aim of this study was to analyze the neuromuscular mechanisms involved in the torque decrease induced by submaximal electromyostimulation (EMS) of the quadriceps muscle. It was hypothesized that torque decrease after EMS would reflect the fatigability of the activated motor units (MUs), but also a reduction in the number of MUs recruited as a result of changes in axonal excitability threshold. Two experiments were performed on 20 men to analyze 1) the supramaximal twitch superimposed and evoked at rest during EMS (Experiment 1, n = 9) and 2) the twitch response and torque-frequency relation of the MUs activated by EMS (Experiment 2, n = 11). Torque loss was assessed by 15 EMS-evoked contractions (50 Hz; 6 s on/6 s off), elicited at a constant intensity that evoked 20% of the maximal voluntary contraction (MVC) torque. The same stimulation intensity delivered over the muscles was used to induce the torque-frequency relation and the single electrical pulse evoked after each EMS contraction (Experiment 2). In Experiment 1, supramaximal twitch was induced by femoral nerve stimulation. Torque decreased by ~60% during EMS-evoked contractions and by only ~18% during MVCs. This was accompanied by a rightward shift of the torque-frequency relation of MUs activated and an increase of the ratio between the superimposed and posttetanic maximal twitch evoked during EMS contraction. These findings suggest that the torque decrease observed during submaximal EMS-evoked contractions involved muscular mechanisms but also a reduction in the number of MUs recruited due to changes in axonal excitability.

  20. Ankle rehabilitation device with two degrees of freedom and compliant joint

    NASA Astrophysics Data System (ADS)

    Racu (Cazacu, C.-M.; Doroftei, I.

    2015-11-01

    We propose a rehabilitation device that we intend to be low cost and easy to manufacture. The system will ensure functionality but also have a small dimensions and low mass, considering the physiological dimensions of the foot and lower leg. To avoid injure of the ankle joint, this device is equipped with a compliant joint between the motor and mechanical transmission. The torque of this joint is intended to be adjustable, according to the degree of ankle joint damage. To choose the material and the dimensions of this compliant joint, in this paper we perform the first stress simulation. The minimum torque is calculated, while the maximum torque is given by the preliminary chosen actuator.

  1. Joint Interdiction

    DTIC Science & Technology

    2016-09-09

    Purpose This publication has been prepared under the direction of the Chairman of the Joint Chiefs of Staff. It sets forth joint doctrine to govern the...governmental and nongovernmental organizations, multinational forces, and other interorganizational partners. It provides military guidance for the...exercise of authority by combatant commanders and other joint force commanders (JFCs), and prescribes joint doctrine for operations and training. It

  2. 40 CFR 1066.240 - Torque transducer verification and calibration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Torque transducer verification and...) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer Specifications § 1066.240 Torque transducer verification and calibration. Calibrate torque-measurement systems as described in 40 CFR 1065.310....

  3. 40 CFR 1066.240 - Torque transducer verification.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Torque transducer verification. 1066... POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer Specifications § 1066.240 Torque transducer verification. Verify torque-measurement systems by performing the verifications described in §§ 1066.270...

  4. 40 CFR 1066.240 - Torque transducer verification and calibration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Torque transducer verification and...) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer Specifications § 1066.240 Torque transducer verification and calibration. Calibrate torque-measurement systems as described in 40 CFR 1065.310....

  5. 40 CFR 90.306 - Dynamometer torque cell calibration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Dynamometer torque cell calibration... Emission Test Equipment Provisions § 90.306 Dynamometer torque cell calibration. (a)(1) Any lever arm used...-cell or transfer standard may be used to verify the torque measurement system. (1) The master...

  6. 40 CFR 90.306 - Dynamometer torque cell calibration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Dynamometer torque cell calibration... Emission Test Equipment Provisions § 90.306 Dynamometer torque cell calibration. (a)(1) Any lever arm used...-cell or transfer standard may be used to verify the torque measurement system. (1) The master...

  7. 40 CFR 90.306 - Dynamometer torque cell calibration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Dynamometer torque cell calibration... Emission Test Equipment Provisions § 90.306 Dynamometer torque cell calibration. (a)(1) Any lever arm used...-cell or transfer standard may be used to verify the torque measurement system. (1) The master...

  8. 40 CFR 90.306 - Dynamometer torque cell calibration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Dynamometer torque cell calibration... Emission Test Equipment Provisions § 90.306 Dynamometer torque cell calibration. (a)(1) Any lever arm used...-cell or transfer standard may be used to verify the torque measurement system. (1) The master...

  9. Performances improvements and torque ripple minimization for VSI fed induction machine with direct control torque.

    PubMed

    Abdelli, R; Rekioua, D; Rekioua, T

    2011-04-01

    This paper describes a torque ripple reduction technique with constant switching frequency for direct torque control (DTC) of an induction motor (IM). This method enables a minimum torque ripple control. In order to obtain a constant switching frequency and hence a torque ripple reduction, we propose a control technique for IM. It consists of controlling directly the electromagnetic torque by using a modulated hysteresis controller. The design methodology is based on space vector modulation (SVM) of electrical machines with digital vector control. MATLAB simulations supported with experimental study are used. The simulation and experimental results of this proposed algorithm show an adequate dynamic to IM; however, the research can be extended to include synchronous motors as well. The implementation of the proposed algorithm is described. It doesn't require any PI controller in the torque control loop. The hardware inverter is controlled digitally using a Texas Instruments TMS320F240 digital signal processor (DSP) with composed C codes for generating the required references. The results obtained from simulation and experiments confirmed the feasibility of the proposed strategy compared to the conventional one.

  10. Joint Disorders

    MedlinePlus

    A joint is where two or more bones come together, like the knee, hip, elbow, or shoulder. Joints can be damaged by many types of injuries or diseases, including Arthritis - inflammation of a joint. It causes pain, stiffness, and swelling. Over time, ...

  11. Joint effect of organic acids and inorganic salts on cloud droplet activation

    NASA Astrophysics Data System (ADS)

    Frosch, M.; Prisle, N. L.; Bilde, M.; Varga, Z.; Kiss, G.

    2010-07-01

    We have investigated CCN properties of internally mixed particles composed of one organic acid (oxalic acid, succinic acid, adipic acid, citric acid, cis-pinonic acid, or nordic reference fulvic acid) and one inorganic salt (sodium chloride or ammonium sulphate). Surface tension and water activity of aqueous model solutions with concentrations relevant for CCN activation were measured using a tensiometer and osmometry, respectively. The measurements were used to calculate Köhler curves, which were compared to measured critical supersaturations of particles with the same chemical compositions, determined with a cloud condensation nucleus counter. Surfactant surface partitioning was not accounted for. For the mixtures containing cis-pinonic acid or fulvic acid, a depression of surface tension was observed, but for the remaining mixtures the effect on surface tension was negligle at concentrations relevant for cloud droplet activation, and water activity was the more significant term in the Köhler equation. The surface tension depression of aqueous solutions containing both organic acid and inorganic salt was approximately the same as or smaller than that of aqueous solutions containing the same mass of the corresponding pure organic acids. Water activity was found to be highly dependent on the type and amount of inorganic salt. Sodium chloride was able to decrease water activity more than ammonium sulphate and both inorganic compounds had a higher effect on water activity than the studied organic acids, and increasing the mass ratio of the inorganic compound led to a decrease in water activity. Water activity measurements were compared to results from the E-AIM model and values estimated from both constant and variable van't Hoff factors to evaluate the performance of these approaches. The correspondence between measuments and estimates was overall good, except for highly concentrated solutions. Critical supersaturations calculated with Köhler theory based on

  12. Exoskeleton control for lower-extremity assistance based on adaptive frequency oscillators: adaptation of muscle activation and movement frequency.

    PubMed

    Aguirre-Ollinger, Gabriel

    2015-01-01

    In this article, we analyze a novel strategy for assisting the lower extremities based on adaptive frequency oscillators. Our aim is to use the control algorithm presented here as a building block for the control of powered lower-limb exoskeletons. The algorithm assists cyclic movements of the human extremities by synchronizing actuator torques with the estimated net torque exerted by the muscles. Synchronization is produced by a nonlinear dynamical system combining an adaptive frequency oscillator with a form of adaptive Fourier analysis. The system extracts, in real time, the fundamental frequency component of the net muscle torque acting on a specific joint. Said component, nearly sinusoidal in shape, is the basis for the assistive torque waveform delivered by the exoskeleton. The action of the exoskeleton can be interpreted as a virtual reduction in the mechanical impedance of the leg. We studied the ability of human subjects to adapt their muscle activation to the assistive torque. Ten subjects swung their extended leg while coupled to a stationary hip joint exoskeleton. The experiment yielded a significant decrease, with respect to unassisted movement, of the activation levels of an agonist/antagonist pair of muscles controlling the hip joint's motion, which suggests the exoskeleton control has potential for assisting human gait. A moderate increase in swing frequency was observed as well. We theorize that the increase in frequency can be explained by the impedance model of the assisted leg. Per this model, subjects adjust their swing frequency in order to control the amount of reduction in net muscle torque.

  13. A Joint Gaussian Process Model for Active Visual Recognition with Expertise Estimation in Crowdsourcing

    PubMed Central

    Long, Chengjiang; Hua, Gang; Kapoor, Ashish

    2015-01-01

    We present a noise resilient probabilistic model for active learning of a Gaussian process classifier from crowds, i.e., a set of noisy labelers. It explicitly models both the overall label noise and the expertise level of each individual labeler with two levels of flip models. Expectation propagation is adopted for efficient approximate Bayesian inference of our probabilistic model for classification, based on which, a generalized EM algorithm is derived to estimate both the global label noise and the expertise of each individual labeler. The probabilistic nature of our model immediately allows the adoption of the prediction entropy for active selection of data samples to be labeled, and active selection of high quality labelers based on their estimated expertise to label the data. We apply the proposed model for four visual recognition tasks, i.e., object category recognition, multi-modal activity recognition, gender recognition, and fine-grained classification, on four datasets with real crowd-sourced labels from the Amazon Mechanical Turk. The experiments clearly demonstrate the efficacy of the proposed model. In addition, we extend the proposed model with the Predictive Active Set Selection Method to speed up the active learning system, whose efficacy is verified by conducting experiments on the first three datasets. The results show our extended model can not only preserve a higher accuracy, but also achieve a higher efficiency. PMID:26924892

  14. Predator and prey activity levels jointly influence the outcome of long-term foraging bouts.

    PubMed

    Sweeney, Kayla; Cusack, Brian; Armagost, Fawn; O'Brien, Timothy; Keiser, Carl N; Pruitt, Jonathan N

    2013-09-01

    Consistent interindividual differences in behavior (i.e., "behavioral types") may be a key factor in determining the outcome of species interactions. Studies that simultaneously account for the behavioral types of individuals in multiple interacting species, such as predator-prey systems, may be particularly strong predictors of ecological outcomes. Here, we test the predator-prey locomotor crossover hypothesis, which predicts that active predators are more likely to encounter and consume prey with the opposing locomotor tendency. We test this hypothesis using intraspecific behavioral variation in both a predator and prey species as predictors of foraging outcomes. We use the old field jumping spider, Phidippus clarus (Araneae, Salticidae), and the house cricket, Acheta domesticus (Orthoptera, Gryllidae), as a model predator-prey system in laboratory mesocosm trials. Stable individual differences in locomotor tendencies were identified in both P. clarus and A. domesticus, and the outcome of foraging bouts depended neither on the average activity level of the predator nor on the average activity level of prey. Instead, an interaction between the activity level of spiders and crickets predicted spider foraging success and prey survivorship. Consistent with the locomotor crossover hypothesis, predators exhibiting higher activity levels consumed more prey when in an environment containing low-activity prey items and vice versa. This study highlights 1) the importance of intraspecific variation in determining the outcome of predator-prey interactions and 2) that acknowledging behavioral variation in only a single species may be insufficient to characterize the performance consequences of intraspecific trait variants.

  15. The effects of imagery training on fast isometric knee extensor torque development.

    PubMed

    de Ruiter, Cornelis J; Hutter, Vana; Icke, Chris; Groen, Bart; Gemmink, Anne; Smilde, Hiltsje; de Haan, Arnold

    2012-01-01

    We hypothesized that imagery training would improve the fast onset of neuromuscular activation and thereby fast knee extensor isometric torque development. Forty young healthy participants, not involved in strength training, were assigned to one of four groups: physical training, imagery training, placebo training or control. The three training groups had three 15 min sessions per week for 4 weeks, with a 90 ° knee angle but were tested also at 120 °. At 90 ° knee angle, maximal torque increased (-8%) similarly in all three training groups. The torque-time integral (contractile impulse) over the first 40 ms after torque onset (TTI40) increased (P < 0.05) after physical training (by -100%), but only at 90 °. This increase was significantly different from the delta values (change pre to post) in the control and placebo groups, whereas delta values in the imagery group were similar to those in the placebo group. The increases in TTI40 following physical training were related (r (2) = 0.81, P < 0.05) to significant increases of knee extensor rectified surface EMG at torque onset (EMG40). In conclusion, only physical training led to a knee angle specific increase of contractile impulse that was significantly different from placebo and controls and that was related to improved onset of neuromuscular activation.

  16. Hand-handle interface force and torque measurement system for pneumatic assembly tool operations: suggested enhancement to ISO 6544.

    PubMed

    Lin, Jia-Hua; McGorry, Raymond W; Chang, Chien-Chi

    2007-05-01

    A hand-handle interface force and torque measurement system is introduced to fill the void acknowledged in the international standard ISO 6544, which governs pneumatic, assembly tool reaction torque and force measurement. This system consists of an instrumented handle with a sensor capable of measuring grip force and reaction hand moment when threaded, fastener-driving tools are used by operators. The handle is rigidly affixed to the tool in parallel to the original tool handle allowing normal fastener-driving operations with minimal interference. Demonstration of this proposed system was made with tools of three different shapes: pistol grip, right angle, and in-line. During tool torque buildup, the proposed system measured operators exerting greater grip force on the soft joint than on the hard joint. The system also demonstrated that the soft joint demanded greater hand moment impulse than the hard joint. The results demonstrate that the measurement system can provide supplemental data useful in exposure assessment with power hand tools as proposed in ISO 6544.

  17. Lower extremity biomechanics during weightlifting exercise vary across joint and load.

    PubMed

    Kipp, Kristof; Harris, Chad; Sabick, Michelle B

    2011-05-01

    The purpose of this study was to determine the effect of load on lower extremity biomechanics during the pull phase of the clean. Kinematic and kinetic data of the 3 joints of the lower extremity were collected while participants performed multiple sets of cleans at 3 percentages: 65, 75, and 85% of 1 repetition maximum (1RM). General linear models with repeated measures were used to assess the influence of load on angular velocities, net torques, powers, and rates of torque development at the ankle, knee, and hip joint. The results suggest that the biomechanical demands required from the lower extremities change with the lifted load and to an extent depend on the respective joint. Most notably, the hip and knee extended significantly faster than the ankle independent of load, whereas the hip and ankle generally produced significantly higher torques than the knee did. Torque, rate of torque development (RTD), and power were maximimal at 85% of 1RM for the ankle joint and at 75% of 1RM for the knee joint. Torque and RTD at the hip were maximal at loads >75% of 1RM. This study provides important novel information about the mechanical demands of a weightlifting exercise and should be heeded in the design of resistance training programs.

  18. A Method for and Issues Associated with the Determination of Space Suit Joint Requirements

    NASA Technical Reports Server (NTRS)

    Matty, Jennifer E.; Aitchison, Lindsay

    2009-01-01

    In the design of a new space suit it is necessary to have requirements that define what mobility space suit joints should be capable of achieving in both a system and at the component level. NASA elected to divide mobility into its constituent parts-range of motion (ROM) and torque- in an effort to develop clean design requirements that limit subject performance bias and are easily verified. Unfortunately, the measurement of mobility can be difficult to obtain. Current technologies, such as the Vicon motion capture system, allow for the relatively easy benchmarking of range of motion (ROM) for a wide array of space suit systems. The ROM evaluations require subjects in the suit to accurately evaluate the ranges humans can achieve in the suit. However, when it comes to torque, there are significant challenges for both benchmarking current performance and writing requirements for future suits. This is reflected in the fact that torque definitions have been applied to very few types of space suits and with limited success in defining all the joints accurately. This paper discussed the advantages and disadvantages to historical joint torque evaluation methods, describes more recent efforts directed at benchmarking joint torques of prototype space suits, and provides an outline for how NASA intends to address joint torque in design requirements for the Constellation Space Suit System (CSSS).

  19. Actuation of a robotic fish caudal fin for low reaction torque.

    PubMed

    Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghee

    2011-07-01

    In this paper, a novel caudal fin for actuating a robotic fish is presented. The proposed caudal fin waves in a vertical direction with a specific spatial shape, which is determined by a so-called shape factor. For a specific shape factor, a traveling wave with a vertical phase difference is formed on a caudal fin during fin motion. It will be shown by the analysis that the maximum reaction torque at the joint of a caudal fin varies depending on the shape factors. Compared with a conventional plate type caudal fin, the proposed fin with a shape factor of 2π can eliminate the reaction torque perfectly, while keeping the propulsion force unchanged. The benefits of the proposed fin will be demonstrated by experiments.

  20. Actuation of a robotic fish caudal fin for low reaction torque

    NASA Astrophysics Data System (ADS)

    Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghee

    2011-07-01

    In this paper, a novel caudal fin for actuating a robotic fish is presented. The proposed caudal fin waves in a vertical direction with a specific spatial shape, which is determined by a so-called shape factor. For a specific shape factor, a traveling wave with a vertical phase difference is formed on a caudal fin during fin motion. It will be shown by the analysis that the maximum reaction torque at the joint of a caudal fin varies depending on the shape factors. Compared with a conventional plate type caudal fin, the proposed fin with a shape factor of 2π can eliminate the reaction torque perfectly, while keeping the propulsion force unchanged. The benefits of the proposed fin will be demonstrated by experiments.

  1. Independent and joint associations of physical activity and fitness with fibromyalgia symptoms and severity: The al-Ándalus project.

    PubMed

    Segura-Jiménez, Víctor; Soriano-Maldonado, Alberto; Estévez-López, Fernando; Álvarez-Gallardo, Inmaculada C; Delgado-Fernández, Manuel; Ruiz, Jonatan R; Aparicio, Virginia A

    2016-09-12

    We examined independent and joint associations of objectively measured physical activity (PA) and physical fitness (PF) with pain, fatigue and the overall impact of fibromyalgia in 386 fibromyalgia women aged 51.2 ± 7.6 years. Levels of PA (light, moderate and vigorous) and PF were measured with triaxial accelerometry and the Senior Fitness Test, respectively. We used the Short-Form health survey-36 pain sub-scale and the Multidimensional Fatigue Inventory to assess pain and multiple dimensions of fatigue, respectively. The impact of fibromyalgia was studied with the Revised Fibromyalgia Impact Questionnaire (FIQR). Both, total PA and global PF were independently associated with pain pressure threshold, SF-36 pain, reduced activity, reduced motivation and FIQR total score (all, P ≤ 0.027). The associations between total PA and symptoms were weaker than those observed between global PF and symptoms. Overall, unfit patients with low PA showed a worse profile that fit patients with high PA (all, P ≤ 0.001). In summary, PA and PF are independently associated with pain, fatigue and the overall impact of fibromyalgia in women. Although PF presented greater associations with symptoms, the results suggest that both being physically active and keep adequate fitness levels might be convenient for fibromyalgia women.

  2. Interpersonal strategies for disturbance attenuation during a rhythmic joint motor action.

    PubMed

    Melendez-Calderon, A; Komisar, V; Burdet, E

    2015-08-01

    Helping someone carry a table is fairly easy; however, our understanding of such joint motor actions is still poorly understood. We studied how pairs of human subjects (referred to as dyads) collaborate physically to attenuate external mechanical perturbations during a target tracking task. Subjects tracked a target moving in a slow and predictable way using wrist flexion/extension movements, with and without destabilizing torque perturbations. Dyad strategies were classified using interaction torques and muscular activity. During unperturbed interactions (baseline), the dyads tended to stabilize on a particular strategy. The baseline strategy was not the same in all dyads, suggesting that the solution to the task was not global but specific to each particular dyad. After several trials of unperturbed interactions, we introduced mechanical vibrations and analyzed the adaptation process. Dyads showed a tendency to counteract the external disturbances by first increasing co-contraction within each subject (independent co-contraction), and then raising the amount of opposing interaction torques (dyadic co-contraction) with increased perturbation amplitude. The introduction of perturbations impelled dyads to abandon their unperturbed baseline strategy and adopt a more common strategy across dyads, suggesting attractor solutions. Our results establish a framework for future human-human interaction studies, and have implications in human motor control as well as human-robot and robot-robot interactions.

  3. Joint effect of organic acids and inorganic salts on cloud droplet activation

    NASA Astrophysics Data System (ADS)

    Frosch, M.; Prisle, N. L.; Bilde, M.; Varga, Z.; Kiss, G.

    2011-04-01

    We have investigated CCN properties of internally mixed particles composed of one organic acid (oxalic acid dihydrate, succinic acid, adipic acid, citric acid, cis-pinonic acid, or Nordic reference fulvic acid) and one inorganic salt (sodium chloride or ammonium sulphate). Surface tension and water activity of aqueous model solutions with concentrations relevant for CCN activation were measured using a tensiometer and osmometry, respectively. The measurements were used to calculate Köhler curves and critical supersaturations, which were compared to measured critical supersaturations of particles with the same chemical compositions, determined with a cloud condensation nucleus counter. Surfactant surface partitioning was not accounted for. For the aqueous solutions containing cis-pinonic acid and fulvic acid, a depression of surface tension was observed, but for the remaining solutions the effect on surface tension was negligible at concentrations relevant for cloud droplet activation. The surface tension depression of aqueous solutions containing both organic acid and inorganic salt was approximately the same as or smaller than that of aqueous solutions containing the same mass of the corresponding pure organic acids. Water activity was found to be highly dependent on the type and amount of inorganic salt. Sodium chloride was able to decrease water activity more than ammonium sulphate and both inorganic salts are predicted to have a smaller Raoult term than the studied organic acids. Increasing the mass ratio of the inorganic salt led to a decrease in water activity. Water activity measurements were compared to results from the E-AIM model and values estimated from both constant and variable van't Hoff factors. The correspondence between measurements and estimates was overall good, except for highly concentrated solutions. Critical supersaturations calculated with Köhler theory based on measured water activity and surface tension, but not accounting for surface

  4. Work and fatigue characteristics of unsuited and suited humans during isolated isokinetic joint motions

    NASA Technical Reports Server (NTRS)

    Gonzalez, L. Javier; Maida, J. C.; Miles, E. H.; Rajulu, S. L.; Pandya, A. K.

    2002-01-01

    The effects of a pressurized suit on human performance were investigated. The suit is known as an Extra-Vehicular Mobility Unit (EMU) and is worn by astronauts while working outside their spacecraft in a low earth orbit. Isolated isokinetic joint torques of three female and three male subjects (all experienced users of the suit in 1G gravity) were measured while working at 100% and 80% of their maximum voluntary torque (MVT, which is synonymous with maximum voluntary contraction (MVC)). It was found that the average decrease in the total amount of work (the sum of the work in each repetition until fatigue) done when the subjects were wearing the EMU were 48% and 41% while working at 100% and 80% MVT, respectively. There is a clear relationship between the MVT and the time and amount of work done until fatigue. Here, the time to fatigue is defined as the ending time of the repetition for which the computed work done during that repetition dropped below 50% of the work done during the first repetition. In general the stronger joints took longer to fatigue and did more work than the weaker joints. It was found that the EMU decreases the work output at the wrist and shoulder joints the most, due to the EMU joint geometry. The EMU also decreased the joint range of motion. The average total amount of work done by the test subjects increased by 5.2% (20.4%) for the unsuited (suited) case, when the test subjects decreased the level of effort from 100% to 80% MVT. Also, the average time to fatigue increased by 9.2% (25.6%) for the unsuited (suited) case, when the test subjects decreased the level of effort from 100% to 80% MVT. It was also found that the experimentally measured torque decay could be predicted by a logarithmic equation. The absolute average errors in the predictions were found to be 18.3% and 18.9% for the unsuited and suited subjects, respectively, when working at 100% MVT, and 22.5% and 18.8% for the unsuited and suited subjects, respectively, when working

  5. Ultrasound-detected activity in rheumatoid arthritis on methotrexate therapy: Which joints and tendons should be assessed to predict unstable remission?

    PubMed

    Janta, Iustina; Valor, Lara; De la Torre, Inmaculada; Martínez-Estupiñán, Lina; Nieto, Juan Carlos; Ovalles-Bonilla, Juan Gabriel; Martínez-Barrio, Julia; Bello, Natalia; Hinojosa, Michelle; Montoro, María; González, Carlos Manuel; López-Longo, Javier; Monteagudo, Indalecio; Carreño, Luis; Naredo, Esperanza

    2016-03-01

    The aim of the study was to investigate the predictive value of different reduced joint ultrasound (US) assessments of synovitis and tenosynovitis in relation to unstable remission in a cohort of rheumatoid arthritis (RA) patients on methotrexate therapy. Forty-seven RA patients (38 women, 9 men), being treated with methotrexate (MTX), in clinical remission as judged by their consultant rheumatologist were evaluated for disease activity according to the Disease Activity Score (DAS) 28 at baseline and 6 months. Sustained remission and unstable remission were defined according to the baseline and 6-month DAS28 and changes in RA therapy during the follow-up. Each patient underwent at baseline a B-mode and power Doppler (PD) assessment of 44 joints and 20 tendons/tendon compartments by a rheumatologist blinded to the clinical and laboratory data. B-mode synovial hypertrophy (SH), synovial PD signal, B-mode tenosynovitis, and Doppler tenosynovitis were scored 0-3. The presence and index of synovial PD signal in 44 joints [odds ratio (OR) 8.21 (p = 0.016) and OR 2.20 (p = 0.049), respectively] and in 12 joints [OR 5.82 (p = 0.041) and OR 4.19 (p = 0.020), respectively], the presence of SH in wrist and MCP joints [OR 4.79 (p = 0.045)], and the presence of synovial PD signal in wrist-MCP-ankle-MTP joints [OR 4.62 (p = 0.046)] were predictors of unstable remission. The 12-joint or wrist-hand-ankle-MTP US assessments can predict unstable remission in RA patients in apparent clinical remission being treated with MTX.

  6. Correlation and prediction of dynamic human isolated joint strength from lean body mass

    NASA Technical Reports Server (NTRS)

    Pandya, Abhilash K.; Hasson, Scott M.; Aldridge, Ann M.; Maida, James C.; Woolford, Barbara J.

    1992-01-01

    A relationship between a person's lean body mass and the amount of maximum torque that can be produced with each isolated joint of the upper extremity was investigated. The maximum dynamic isolated joint torque (upper extremity) on 14 subjects was collected using a dynamometer multi-joint testing unit. These data were reduced to a table of coefficients of second degree polynomials, computed using a least squares regression method. All the coefficients were then organized into look-up tables, a compact and convenient storage/retrieval mechanism for the data set. Data from each joint, direction and velocity, were normalized with respect to that joint's average and merged into files (one for each curve for a particular joint). Regression was performed on each one of these files to derive a table of normalized population curve coefficients for each joint axis, direction, and velocity. In addition, a regression table which included all upper extremity joints was built which related average torque to lean body mass for an individual. These two tables are the basis of the regression model which allows the prediction of dynamic isolated joint torques from an individual's lean body mass.

  7. Wrist torque estimation during simultaneous and continuously changing movements: surface vs. untargeted intramuscular EMG.

    PubMed

    Kamavuako, Ernest N; Scheme, Erik J; Englehart, Kevin B

    2013-06-01

    In this paper, the predictive capability of surface and untargeted intramuscular electromyography (EMG) was compared with respect to wrist-joint torque to quantify which type of measurement better represents joint torque during multiple degrees-of-freedom (DoF) movements for possible application in prosthetic control. Ten able-bodied subjects participated in the study. Surface and intramuscular EMG was recorded concurrently from the right forearm. The subjects were instructed to track continuous contraction profiles using single and combined DoF in two trials. The association between torque and EMG was assessed using an artificial neural network. Results showed a significant difference between the two types of EMG (P < 0.007) for all performance metrics: coefficient of determination (R(2)), Pearson correlation coefficient (PCC), and root mean square error (RMSE). The performance of surface EMG (R(2) = 0.93 ± 0.03; PCC = 0.98 ± 0.01; RMSE = 8.7 ± 2.1%) was found to be superior compared with intramuscular EMG (R(2) = 0.80 ± 0.07; PCC = 0.93 ± 0.03; RMSE = 14.5 ± 2.9%). The higher values of PCC compared with R(2) indicate that both methods are able to track the torque profile well but have some trouble (particularly intramuscular EMG) in estimating the exact amplitude. The possible cause for the difference, thus the low performance of intramuscular EMG, may be attributed to the very high selectivity of the recordings used in this study.

  8. Assessment of the Breakaway Torque at the Posterior Pelvic Ring in Human Cadavers

    PubMed Central

    Bastian, Johannes Dominik; Bergmann, Mathias; Schwyn, Ronald; Keel, Marius Johann Baptist; Benneker, Lorin Michael

    2015-01-01

    ABSTRACT Purpose: To enhance the diminished screw purchase in cancellous, osteoporotic bone following the fixation of posterior pelvic ring injuries by iliosacral screws an increased bone-implant contact area using modificated screws, techniques or bone cement may become necessary. The aim of the study was to identify sites within the pathway of iliosacral screws requiring modifications of the local bone or the design of instrumentations placed at this site. Materials and Methods: The breakaway torque was measured mechanically at the iliosacral joint (“ISJ”), the sacral lateral mass (“SLM”) and the center of the S1 (“CS1”), at a superior and an inferior site under fluoroscopic control on five human cadaveric specimens (3 female; mean age 87 years, range: 76–99) using the DensiProbe™Spine device. Results: The measured median (range) breakaway torque was 0.63 Nm (0.31–2.52) at the “iliosacral joint”, 0.14 Nm (0.05–1.22) at the “sacral lateral mass”, 0.57 Nm (0.05–1.42) at the “S1 center.” The “sacral lateral mass” breakaway torque was lower than compared to that at the “iliosacral joint” (p < .001) or “S1 center” (p < .001). The median (range) breakaway torque measured at all superior measurement points was 0.52 Nm (0.10–2.52), and 0.48 Nm (0.05–1.18) at all inferior sites. The observed difference was statistically significant (p < .05). Conclusions: The lateral mass of the sacrum provides the lowest bone quality for implant anchorage. Iliosacral screws should be placed as superior as safely possible, should bridge the iliosacral joint and may allow for cement application at the lateral mass of the sacrum through perforations. PMID:26270866

  9. 76 FR 51123 - Agency Information Collection Activities; Submission for OMB Review and Approval; Joint Comment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-17

    ... Consumer Protection Act (Dodd-Frank Act). As part of the comprehensive package of financial regulatory... Information and Regulatory Affairs, Office of Management and Budget, New Executive Office Building, Room 10235... Officers, (202) 874-5090 or (202) 874-6055, Legislative and Regulatory Activities Division, Office of...

  10. Guided Participation in Three Youth Activism Organizations: Facilitation, Apprenticeship, and Joint Work

    ERIC Educational Resources Information Center

    Kirshner, Ben

    2008-01-01

    Multiracial youth activism groups, based in working class and poor neighborhoods, seek to improve social conditions by organizing grassroots campaigns. Campaigns such as these, which require sophisticated planning, organizing, and advocacy skills, are noteworthy not just for their political impact, but also because of the insights they provide…

  11. 78 FR 30922 - Agency Information Collection Activities: Submission for OMB Review; Joint Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ..., identifying areas of focus for on-site and off-site examinations, and monetary and other public policy... distribution of institutions, types of activities in which they are engaged, and existence of foreign offices.... Type of Review: Revision and extension of currently approved collections. General Description...

  12. 76 FR 77315 - Agency Information Collection Activities: Submission for OMB Review; Joint Comment Reque