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Sample records for multi-ionic kinematic investigation

  1. Investigating The Kinematics of Canids and Felids

    Science.gov (United States)

    Sur, D.

    2016-12-01

    For all organisms, metabolic energy is critical for survival. While moving efficiently is a necessity for large carnivores, the influence of kinematics on energy demand remains poorly understood. We measured the kinematics of dogs, wolves, and pumas to detect any differences in their respective energy expenditures. Using 22 kinematic parameters measured on 78 videos, we used one-way ANOVAs and paired T-tests to compare 5 experimental treatments among gaits in dogs (n=11 in 3 breed groups), wolves (n=2), and pumas (n=2). Across the measured parameters, we found greater kinematic similarity than expected among dog breeds and no trend in any of the 22 parameters regarding the effect of steepness on locomotion mechanics. Similarly, treadmill kinematics were nearly identical to those measured during outdoor movement. However, in 3 inches of snow, we observed significant differences (pwolf. When comparing canids (wolves and dogs) to a felid (pumas), we found that pumas and dogs are the most kinematically distinct (differing in 13 of 22 parameters, compared with 5 of 22 for wolves and pumas). Lastly, compared with wolves, walking pumas had larger head angles (p=0.0025), forelimb excursion angles (p=0.0045), and hindlimb excursion angles (p=0.0327). After comparing the energetics of pumas and dogs with their respective kinematics, we noted that less dynamic kinematics result in energy savings. Through tracking the locations and gait behavior of large carnivores, novel sensor technology can reveal how indoor kinematics applies to wild animals and improve the conservation of these species.

  2. Fission of highly excited nuclei investigated in complete kinematic measurements

    International Nuclear Information System (INIS)

    Rodriguez-Sanchez, J. L.; Benlliure, J.; Taieb, J.; Avarez-Pol, H.; Audouin, L.; Ayyad, Y.; Belier, G.; Boutoux, G.; Casarejos, E.; Chatillon, A.; Cortina-Gil, D.; Gorbinet, T.; Heinz, A.; Kelic-Heil, A.; Kurz, N.; Laurent, B.; Martin, J. F.; Paradela, C.; Pellereau, E.; Pietras, B.; Prochazka, A.; Ramos, D.; Rodriguez-Tajes, C.; Rossi, D.; Simon, H.; Tassan-Got, L.; Vargas, J.; Voss, B.

    2013-01-01

    Fission is an extremely complex mechanism that requires a dynamical approach to describe the evolution of the process in terms of intrinsic and collective excitations of the nuclear constituents. In order to determine these effects a complex experimental setup was mounted at GSI, which allowed us for the first time the full identification in charge and mass of all fission fragments thanks to a magnetic separation and the use of the inverse kinematic technique. Moreover, we also measured the neutron multiplicities and the light-charged particles emitted in coincidence with fission. These complete kinematic measurements will be used to define sensitive observables to dissipative and transient effects in fission. In this manuscript we present the first results for the total fission cross sections. (authors)

  3. An investigation into the kinematics of 2 cervical manipulation techniques.

    Science.gov (United States)

    Williams, Jonathan M; Cuesta-Vargas, Antonio I

    2013-01-01

    The purpose of this study was to quantify the kinematics of the premanipulative position, the angular displacement, and velocity of thrust of 2 commonly used cervical spine manipulative procedures using inertial sensor technology. Thirteen asymptomatic subjects (7 females; mean age, 25.3 years; mean height, 170.9 cm; mean weight, 65.3 kg) received a right-handed and left-handed downslope and upslope manipulation, aimed at C4/5 while cervical kinematics were measured using an inertial sensor mounted on the forehead of the subject. One therapist used the upslope, and another therapist, the downslope, as was their preferred method. t tests were used to compare techniques and handiness. The results demonstrated differences in the kinematics between the 2 techniques. The downslope manipulation was associated with a mean premanipulative position of 24.8° side bending and 2.7° rotation, thrust displacement magnitude comprising of 4.5° side bending and 5.4° rotation with thrust velocity comprising, on average, of 57.5°/s side bending and 74.8°/s rotation. Upslope premanipulation was on average comprised of 30.1° side bending and 8.4° rotation, thrust displacement comprised of 4.5° side bending and 12.7° rotation with thrust velocity comprising of 75.9°/s side bending and 194.7°/s rotation. The results of this study demonstrate that there are different kinematic patterns for these 2 manipulative techniques. Copyright © 2013 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  4. Local Stellar Kinematics from RAVE data - V. Kinematic Investigation of the Galaxy with Red Clump Stars

    Science.gov (United States)

    Karaali, S.; Bilir, S.; Ak, S.; Gökçe, E. Yaz; Önal, Ö.; Ak, T.

    2014-02-01

    We investigated the space velocity components of 6 610 red clump (RC) stars in terms of vertical distance, Galactocentric radial distance and Galactic longitude. Stellar velocity vectors are corrected for differential rotation of the Galaxy which is taken into account using photometric distances of RC stars. The space velocity components estimated for the sample stars above and below the Galactic plane are compatible only for the space velocity component in the direction to the Galactic rotation of the thin disc stars. The space velocity component in the direction to the Galactic rotation (V lsr) shows a smooth variation relative to the mean Galactocentric radial distance (Rm ), while it attains its maximum at the Galactic plane. The space velocity components in the direction to the Galactic centre (U lsr) and in the vertical direction (W lsr) show almost flat distributions relative to Rm , with small changes in their trends at Rm ~ 7.5 kpc. U lsr values estimated for the RC stars in quadrant 180° RC stars above the Galactic plane move towards the North Galactic Pole, whereas those below the Galactic plane move in the opposite direction. In the case of quadrant 180° RC stars above and below the Galactic plane move towards the Galactic plane. We stated that the Galactic long bar is the probable origin of many, but not all, of the detected features.

  5. Kinematic Investigation of Lingual Movement in Words of Increasing Length in Acquired Apraxia of Speech

    Science.gov (United States)

    Bartle-Meyer, Carly J.; Goozee, Justine V.; Murdoch, Bruce E.

    2009-01-01

    The current study aimed to use electromagnetic articulography (EMA) to investigate the effect of increasing word length on lingual kinematics in acquired apraxia of speech (AOS). Tongue-tip and tongue-back movement was recorded for five speakers with AOS and a concomitant aphasia (mean age = 53.6 years; SD = 12.60) during target consonant…

  6. Investigation of kinematics of knuckling shot in soccer

    Science.gov (United States)

    Asai, T.; Hong, S.

    2017-02-01

    In this study, we use four high-speed video cameras to investigate the swing characteristics of the kicking leg while delivering the knuckling shot in soccer. We attempt to elucidate the impact process of the kicking foot at the instant of its impact with the ball and the technical mechanisms of the knuckling shot via comparison of its curved motion with that of the straight and curved shots. Two high-speed cameras (Fastcam, Photron Inc., Tokyo, Japan; 1000 fps, 1024 × 1024 pixels) are set up 2 m away from the site of impact with a line of sight perpendicular to the kicking-leg side. In addition, two semi-high-speed cameras (EX-F1, Casio Computer Co., Ltd., Tokyo, Japan; 300 fps; 720 × 480 pixels) are positioned, one at the rear and the other on the kicking-leg side, to capture the kicking motion. We observe that the ankle joint at impact in the knuckling shot flexes in an approximate L-shape in a manner similar to the joint flexing for the curve shot. The hip's external rotation torque in the knuckling shot is greater than those of other shots, which suggests the tendency of the kicker to push the heel forward and impact with the inside of the foot. The angle of attack in the knuckling shot is smaller than that in other shots, and we speculate that this small attack angle is a factor in soccer kicks which generate shots with smaller rotational frequencies of the ball.

  7. Parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites: analytical and numerical investigations

    Directory of Open Access Journals (Sweden)

    Marco Romano

    2017-01-01

    Full Text Available A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by analytical and numerical investigations. Due to the definition of plain representative sequences of balanced plain-weave fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. The mesomechanic kinematic can be observed in both the analytic model and the FE-analyses. The analytic model yields hyperbolic correlations due to the strongly simplifying presumptions that neglect elasticity. In contrast the FE-analyses yield linear correlations in much smaller amounts due to the consideration of elastic parts, yet distinctly.

  8. Investigation on forces in frictional kinematic pairs to assess their influence on shock absorber characteristics

    Directory of Open Access Journals (Sweden)

    Janusz GARDULSKI

    2008-01-01

    Full Text Available In telescopic shock absorbers there are two kinematic pairs where dry,semi-dry or fluid friction is most likely to occur. Higher values of friction forces are noted in piston rod-slideway pair due to its sealing function and consequently worse lubricating conditions. The aim of the tests was to assess the influence of forces occurring in frictional kinematic pairs on damping characteristics of shock absorbers. The tests were performed on new and fluid-free shock absorbers for various working strokes and various extortion frequencies.

  9. Investigation of first ray mobility during gait by kinematic fluoroscopic imaging-a novel method

    Directory of Open Access Journals (Sweden)

    Martin Heiner

    2012-02-01

    Full Text Available Abstract Background It is often suggested that sagittal instability at the first tarso-metatarsal joint level is a primary factor for hallux valgus and that sagittal instability increases with the progression of the deformity. The assessment of the degree of vertical instability is usually made by clinical evaluation while any measurements mostly refer to a static assessment of medial ray mobility (i.e. the plantar/dorsal flexion in the sagittal plane. Testing methods currently available cannot attribute the degree of mobility to the corresponding anatomical joints making up the medial column of the foot. The aim of this study was to develop a technique which allows for a quantification of the in-vivo sagittal mobility of the joints of the medial foot column during the roll-over process under full weight bearing. Methods Mobility of first ray bones was investigated by dynamic distortion-free fluoroscopy (25 frames/s of 14 healthy volunteers and 8 patients with manifested clinical instability of the first ray. A CAD-based evaluation method allowed the determination of mobility and relative displacements and rotations of the first ray bones within the sagittal plane during the stance phase of gait. Results Total flexion of the first ray was found to be 13.63 (SD 6.14 mm with the healthy volunteers and 13.06 (SD 8.01 mm with the patients (resolution: 0.245 mm/pixel. The dorsiflexion angle was 5.27 (SD 2.34 degrees in the healthy volunteers and increased to 5.56 (SD 3.37 degrees in the patients. Maximum rotations were found at the naviculo-cuneiform joints and least at the first tarso-metatarsal joint level in both groups. Conclusions Dynamic fluoroscopic assessment has been shown to be a valuable tool for characterisation of the kinematics of the joints of the medial foot column during gait. A significant difference in first ray flexion and angular rotation between the patients and healthy volunteers however could not be found.

  10. Inverse Kinematics

    Directory of Open Access Journals (Sweden)

    Joel Sereno

    2010-01-01

    Full Text Available Inverse kinematics is the process of converting a Cartesian point in space into a set of joint angles to more efficiently move the end effector of a robot to a desired orientation. This project investigates the inverse kinematics of a robotic hand with fingers under various scenarios. Assuming the parameters of a provided robot, a general equation for the end effector point was calculated and used to plot the region of space that it can reach. Further, the benefits obtained from the addition of a prismatic joint versus an extra variable angle joint were considered. The results confirmed that having more movable parts, such as prismatic points and changing angles, increases the effective reach of a robotic hand.

  11. A Multidisciplinary Investigation of the Effects of Competitive State Anxiety on Serve Kinematics in Table Tennis

    Directory of Open Access Journals (Sweden)

    Ngo Vuong

    2017-01-01

    Full Text Available Displays of anxiety in table tennis were assessed through subjective (a self-report questionnaire, physiological (heart-rate variability and kinematic variables. Using a within-group crossover design, 9 university-level table tennis players completed a series of serves under low- and high-anxiety conditions. Anxiety manipulation was achieved through the introduction of a national standard table tennis player, known to the participants, to receive serves in the high-anxiety condition, whilst serves were received by no opponent in the low-anxiety condition. Automated motion capture systems consisting of high-speed 3D motion cameras and analytical software (QUALISYS determined the subject’s movement kinematics: bat face angle (degrees and serve routine duration (s. Self-reported state anxiety (MRF-Likert and heart rate measurements were collected to examine changes between conditions. Contrary to the hypothesis, bat face angles did not change significantly between anxiety conditions (F (1.8 = 2.791, p = 0.133 and movement times were faster in the high-anxiety condition. In light of these findings, research into other facets of movement behaviour must be analysed to gain further understanding of the effects of anxiety on performance, which remain unclear.

  12. Human Kinematics of Cochlear Implant Surgery: An Investigation of Insertion Micro-Motions and Speed Limitations.

    Science.gov (United States)

    Kesler, Kyle; Dillon, Neal P; Fichera, Loris; Labadie, Robert F

    2017-09-01

    Objectives Document human motions associated with cochlear implant electrode insertion at different speeds and determine the lower limit of continuous insertion speed by a human. Study Design Observational. Setting Academic medical center. Subjects and Methods Cochlear implant forceps were coupled to a frame containing reflective fiducials, which enabled optical tracking of the forceps' tip position in real time. Otolaryngologists (n = 14) performed mock electrode insertions at different speeds based on recommendations from the literature: "fast" (96 mm/min), "stable" (as slow as possible without stopping), and "slow" (15 mm/min). For each insertion, the following metrics were calculated from the tracked position data: percentage of time at prescribed speed, percentage of time the surgeon stopped moving forward, and number of direction reversals (ie, going from forward to backward motion). Results Fast insertion trials resulted in better adherence to the prescribed speed (45.4% of the overall time), no motion interruptions, and no reversals, as compared with slow insertions (18.6% of time at prescribed speed, 15.7% stopped time, and an average of 18.6 reversals per trial). These differences were statistically significant for all metrics ( P implant electrode at 15 mm/min is not feasible for human operators. The lower limit of continuous forward insertion is 52 mm/min on average. Guidelines on manual insertion kinematics should consider this practical limit of human motion.

  13. Relativistic Kinematics

    OpenAIRE

    Sahoo, Raghunath

    2016-01-01

    This lecture note covers Relativistic Kinematics, which is very useful for the beginners in the field of high-energy physics. A very practical approach has been taken, which answers "why and how" of the kinematics useful for students working in the related areas.

  14. AN INVESTIGATION OF A REFERENCE POSTURE USED IN DETERMINING REARFOOT KINEMATICS FOR BOTH HEALTHY AND PATELLOFEMORAL PAIN SYNDROME INDIVIDUALS

    Directory of Open Access Journals (Sweden)

    Pazit Levinger

    2005-09-01

    Full Text Available The choice of a reference posture is important when investigating rearfoot motion in clinical populations. The reference posture used may affect the magnitude of the peak angles and therefore may not enable comparison of the rearfoot kinematics across different populations. This study examined the relationship between the rearfoot frontal plane pattern of motion and three reference postures during the stance phase of walking in healthy and patellofemoral pain syndrome (PFPS subjects. The three reference postures investigated were: Relaxed Standing posture, subtalar joint neutral position (STJN and when the calcaneus and the lower leg were vertically aligned (Vertical Alignment. The rearfoot inversion/eversion during the stance phase was measured in 14 healthy subjects and 13 subjects with diagnosed PFPS using three dimensional motion analysis with the three different reference postures. The graphs of rearfoot inversion/eversion motion were overlaid with the angle at the rearfoot in the static posture and any intersection between the static angle and rearfoot motion was noted. An ANOVA showed significant differences in static posture between the groups for Relaxed Standing (p = 0.01, and STJN (p = 0.02. For both groups, with Relaxed Standing as a reference posture, the mean rearfoot pattern of motion did not intersect the Relaxed Standing static angle during the stance phase. The use of Vertical Alignment reference posture, however, showed an intersection of this reference posture through the rearfoot pattern of motion. The use of the Vertical Alignment reference posture also generated a typical rearfoot motion pattern for both groups and therefore it may be an appropriate reference posture for both healthy and PFPS individuals

  15. A multi-modal geological investigation framework for subsurface modeling and kinematic monitoring of a slow-moving landslide complex in Colorado, United States

    Science.gov (United States)

    Lowry, B. W.; Zhou, W.; Smartgeo

    2010-12-01

    The Muddy Creek landslide complex is a large area of active and reactivating landslides that impact the operation of both a state highway and Paonia Reservoir in Gunnison County, Colorado, United States. Historically, the monitoring of this slide has been investigated using disparate techniques leading to protracted analysis and project knowledge attrition. We present an integrated, data-driven investigation framework that supports continued kinematic monitoring, document cataloging, and subsurface modeling of the landslide complex. A geospatial information system (GIS) was integrated with a visual programming based subsurface model to facilitate modular integration of monitoring data with borehole information. Subsurface modeling was organized by material type and activity state based on multiple sources of kinematic measurement. The framework is constructed to modularly integrate remotely sensed imagery and other spatial datasets such as ASTER, InSAR, and LiDAR derived elevation products as more precise datasets become available. The framework allows for terrestrial LiDAR survey error estimation, borehole siting, and placement of wireless sensor (GPS, accelerometers, geophysical ) networks for optimized spatial relevance and utility. Coordinated spatial referencing within the GIS facilitates geotechnical and hydrogeological modeling input generation and common display of modeling outputs. Kinematic data fusion techniques are accomplished with integration of instrumentation, surficial feature tracking, subsurface classification, and 3D interpolation. The framework includes dynamic decision support including landslide dam failure estimates, back-flooding scenario planning that can be accessed by multiple agencies and stakeholders.

  16. Rational kinematics

    CERN Document Server

    Angeles, Jorge

    1988-01-01

    A rational study of kinematics is a treatment of the subject based on invariants, i.e., quantities that remain essentially unchanged under a change of observer. An observer is understood to be a reference frame supplied with a clock (Truesdell 1966). This study will therefore include an introduction to invariants. The language of these is tensor analysis and multilinear algebra, both of which share many isomorphic relations, These subjects are treated in full detail in Ericksen (1960) and Bowen and Wang (1976), and hence will not be included here. Only a short account of notation and definitions will be presented. Moreover, definitions and basic concepts pertaining to the kinematics of rigid bodies will be also included. Although the kinematics of rigid bodies can be regarded as a particular case of the kinematics of continua, the former deserves attention on its own merits for several reasons. One of these is that it describes locally the motions undergone by continua. Another reason is that a whole area of ...

  17. The time course of phase correction: A kinematic investigation of motor adjustment to timing perturbations during sensorimotor synchronization

    Science.gov (United States)

    Hove, Michael J.; Balasubramaniam, Ramesh; Keller, Peter E.

    2014-01-01

    Synchronizing movements with a beat requires rapid compensation for timing errors. The phase-correction response (PCR) has been studied extensively in finger tapping by shifting a metronome onset and measuring the adjustment of the following tap time. How the response unfolds during the subsequent tap cycle remains unknown. Using motion capture, we examined finger kinematics during the PCR. Participants tapped with a metronome containing phase perturbations. They tapped in ‘legato’ and ‘staccato’ style at various tempi, which altered the timing of the constituent movement stages (dwell at the surface, extension, flexion). After a phase perturbation, tapping kinematics changed compared to baseline, and the PCR was distributed differently across movement stages. In staccato tapping, the PCR trajectory changed primarily during finger extension across tempi. In legato tapping, at fast tempi the PCR occurred primarily during extension, whereas at slow tempi most phase correction was already completed during dwell. Across conditions, timing adjustments occurred primarily 100-250 ms into the following tap cycle. The change in movement around 100 ms represents the time to integrate information into an already planned movement and the rapidity suggests a subcortical route. PMID:25151103

  18. Biquaternions and relativistic kinematics

    International Nuclear Information System (INIS)

    Bogush, A.A.; Kurochkin, Yu.A.; Fedorov, F.I.

    1979-01-01

    The problems concerning the use of quaternion interpretation of the Lorentz group vector parametrization are considered for solving relativistic kinematics problems. A vector theory convenient for describing the characteristic features of the Lobachevsky space is suggested. The kinematics of elementary particle scattering is investigated on the basis of this theory. A synthesis of vector parametrization and of quaternion calculation has been shown to lead to natural formulation of the theory of vectors in the three-dimensional Lobachevsky space, realized on mass hyperboloids of relativistic particles

  19. Impact of Simulated Knee Injuries on the Patellofemoral and Tibiofemoral Kinematics Investigated with an Electromagnetic Tracking Approach: A Cadaver Study

    Directory of Open Access Journals (Sweden)

    Björn Rath

    2018-01-01

    Full Text Available Purpose. The purpose of this study was to evaluate the approach of using an electromagnetic tracking (EMT system for measuring the effects of stepwise, simulated knee injuries on patellofemoral (PF and tibiofemoral (TF kinematics. Methods. Three cadaver knees were placed in a motion rig. EMT sensors were mounted on the patella, the medial/lateral femoral epicondyles, the tibial condyle, and the tibial tuberosity (TT. After determining the motion of an intact knee, three injuries were simulated and the resulting bony motion was tracked. Results. Starting with the intact knee fully extended (0° flexion and bending it to approximately 20°, the patella shifted slightly in the medial direction. Then, while bending the knee to the flexed position (90° flexion, the patella shifted progressively more laterally. After transecting the anterior cruciate ligament (ACL, the base of the medial menisci (MM at the pars intermedia, and the medial collateral ligament (MCL, individual changes were observed. For example, the medial femoral epicondyle displayed a medial lift-off in all knees. Conclusion. We demonstrated that our EMT approach is an acceptable method to accurately measure PF joint motion. This method could also enable visualization and in-depth analysis of in vivo patellar function in total knee arthroplasty, if it is established for routine clinical use.

  20. An Investigation of the Kinematic and Microphysical Control of Lightning Rate, Extent and NOX Production using DC3 Observations and the NASA Lightning Nitrogen Oxides Model (LNOM)

    Science.gov (United States)

    Carey, L. D.; Koshak, W. J.; Peterson, H. S.; Matthee, R.; Bain, A. L.

    2013-12-01

    The Deep Convective Clouds and Chemistry (DC3) experiment seeks to quantify the relationship between storm physics, lightning characteristics and the production of nitrogen oxides via lightning (LNOX). The focus of this study is to investigate the kinematic and microphysical control of lightning properties, particularly those that may govern LNOX production, such as flash rate, type and extent across Alabama during DC3. Prior studies have demonstrated that lightning flash rate and type is correlated to kinematic and microphysical properties in the mixed-phase region of thunderstorms such as updraft volume and graupel mass. More study is required to generalize these relationships in a wide variety of storm modes and meteorological conditions. Less is known about the co-evolving relationship between storm physics, morphology and three-dimensional flash extent, despite its importance for LNOX production. To address this conceptual gap, the NASA Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection NetworkTM (NLDN) observations following ordinary convective cells through their lifecycle. LNOM provides estimates of flash rate, flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOX production profiles. For this study, LNOM is applied in a Lagrangian sense to multicell thunderstorms over Northern Alabama on two days during DC3 (21 May and 11 June 2012) in which aircraft observations of NOX are available for comparison. The LNOM lightning characteristics and LNOX production estimates are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler and polarimetric radar analyses applied to observations from a nearby radar network, including the UAH Advanced Radar for Meteorological and Operational Research (ARMOR). Given complex multicell evolution, particular attention is paid to storm morphology, cell

  1. An Investigation of the Kinematic and Microphysical Control of Lightning Rate, Extent and NOx Production using DC3 Observations and the NASA Lightning Nitrogen Oxides Model (LNOM)

    Science.gov (United States)

    Carey, Lawrence; Koshak, William; Peterson, Harold; Matthee, Retha; Bain, Lamont

    2013-01-01

    The Deep Convective Clouds and Chemistry (DC3) experiment seeks to quantify the relationship between storm physics, lightning characteristics and the production of nitrogen oxides via lightning (LNOx). The focus of this study is to investigate the kinematic and microphysical control of lightning properties, particularly those that may govern LNOx production, such as flash rate, type and extent across Alabama during DC3. Prior studies have demonstrated that lightning flash rate and type is correlated to kinematic and microphysical properties in the mixed-phase region of thunderstorms such as updraft volume and graupel mass. More study is required to generalize these relationships in a wide variety of storm modes and meteorological conditions. Less is known about the co-evolving relationship between storm physics, morphology and three-dimensional flash extent, despite its importance for LNOx production. To address this conceptual gap, the NASA Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection Network(TM) (NLDN) observations following ordinary convective cells through their lifecycle. LNOM provides estimates of flash rate, flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles. For this study, LNOM is applied in a Lagrangian sense to multicell thunderstorms over Northern Alabama on two days during DC3 (21 May and 11 June 2012) in which aircraft observations of NOx are available for comparison. The LNOM lightning characteristics and LNOX production estimates are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler and polarimetric radar analyses applied to observations from a nearby radar network, including the UAH Advanced Radar for Meteorological and Operational Research (ARMOR). Given complex multicell evolution, particular attention is paid to storm morphology, cell

  2. Parallel kinematics type, kinematics, and optimal design

    CERN Document Server

    Liu, Xin-Jun

    2014-01-01

    Parallel Kinematics- Type, Kinematics, and Optimal Design presents the results of 15 year's research on parallel mechanisms and parallel kinematics machines. This book covers the systematic classification of parallel mechanisms (PMs) as well as providing a large number of mechanical architectures of PMs available for use in practical applications. It focuses on the kinematic design of parallel robots. One successful application of parallel mechanisms in the field of machine tools, which is also called parallel kinematics machines, has been the emerging trend in advanced machine tools. The book describes not only the main aspects and important topics in parallel kinematics, but also references novel concepts and approaches, i.e. type synthesis based on evolution, performance evaluation and optimization based on screw theory, singularity model taking into account motion and force transmissibility, and others.   This book is intended for researchers, scientists, engineers and postgraduates or above with interes...

  3. Investigation of kinematic demixing of polymer blend deuterated polystyrene (d-PS) and polyvinylmethylether (PVME) with neutron small angle scattering

    International Nuclear Information System (INIS)

    Yee Madeira, H.T.

    1989-03-01

    The scope of this work is the investigation of the system PV ME/d-PS by small angle neutron scattering (SANS). The measurements were done with a pinhole-camera and a high resolution double crystal diffractometer and covered the resolution range from 10 -3 to 3x10 -2 A -1 and 2x10 -5 to 6x10 -4 A -1 respectively. As a basis for these investigations the phase diagram of a PVME/d-PS mixture was measured with SANS. The spinodal for different curve between stable and demixing region was obtained. For PVME with molecular weights M ω =60000 and d-PS with M ω =215103 the critical point is at the concentration Φ=0.2. From the spinodal and the structure factor the Flory-Huggins parameter Χ could be extracted as a function of temperature. It was found that Χ=0 for T comp =135 0 C and Χ is independent of the molecular weight within the accuracy of the data, thus Χ may be associated with a local interaction parameter. The scattering experiments for the determination of the spinodal confirmed the mean-field behaviour of the critical scattering which was earlier found by Herkt-Maetzky and Schelten. Further, the time dependence of the structure factor in the miscibility gap was investigated. From the structure factors, specially from the position Q max of their maxima, a characteristic length was extracted. (orig./RB) [de

  4. Kinematic parameters of signed verbs.

    Science.gov (United States)

    Malaia, Evie; Wilbur, Ronnie B; Milkovic, Marina

    2013-10-01

    Sign language users recruit physical properties of visual motion to convey linguistic information. Research on American Sign Language (ASL) indicates that signers systematically use kinematic features (e.g., velocity, deceleration) of dominant hand motion for distinguishing specific semantic properties of verb classes in production ( Malaia & Wilbur, 2012a) and process these distinctions as part of the phonological structure of these verb classes in comprehension ( Malaia, Ranaweera, Wilbur, & Talavage, 2012). These studies are driven by the event visibility hypothesis by Wilbur (2003), who proposed that such use of kinematic features should be universal to sign language (SL) by the grammaticalization of physics and geometry for linguistic purposes. In a prior motion capture study, Malaia and Wilbur (2012a) lent support for the event visibility hypothesis in ASL, but there has not been quantitative data from other SLs to test the generalization to other languages. The authors investigated the kinematic parameters of predicates in Croatian Sign Language ( Hrvatskom Znakovnom Jeziku [HZJ]). Kinematic features of verb signs were affected both by event structure of the predicate (semantics) and phrase position within the sentence (prosody). The data demonstrate that kinematic features of motion in HZJ verb signs are recruited to convey morphological and prosodic information. This is the first crosslinguistic motion capture confirmation that specific kinematic properties of articulator motion are grammaticalized in other SLs to express linguistic features.

  5. Kinematic Tests of Small Arms

    Science.gov (United States)

    2016-03-15

    muzzle devices, such as flash suppressors and muzzle compensators, if the items are designed to be operator removable. Use the ammunition that will...muzzle brake or adding a sound suppressor . A kinematics study is also a diagnostic tool to investigate weapon problems such as poor functioning with

  6. Prediction of Kinematic and Kinetic Performance in a Drop Vertical Jump with Individual Anthropometric Factors in Adolescent Female Athletes: Implications for Cadaveric Investigations

    Science.gov (United States)

    Bates, Nathaniel A.; Myer, Gregory D.; Hewett, Timothy E.

    2014-01-01

    Anterior cruciate ligament injuries are common, expensive to repair, and often debilitate athletic careers. Robotic manipulators have evaluated knee ligament biomechanics in cadaveric specimens, but face limitations such as accounting for variation in bony geometry between specimens that may influence dynamic motion pathways. This study examined individual anthropometric measures for significant linear relationships with in vivo kinematic and kinetic performance and determined their implications for robotic studies. Anthropometrics and 3D motion during a 31 cm drop vertical jump task were collected in high school female basketball players. Anthropometric measures demonstrated differential statistical significance in linear regression models relative to kinematic variables (P-range 0.20) relative to peak flexion moment, peak adduction moment, flexion moment range, abduction moment range, and internal rotation moment range. The current findings indicate that anthropometric measures are less associated with kinematics than with kinetics. Relative to the robotic manipulation of cadaveric limbs, the results do not support the need to normalize kinematic rotations relative to specimen dimensions. PMID:25266933

  7. Prediction of kinematic and kinetic performance in a drop vertical jump with individual anthropometric factors in adolescent female athletes: implications for cadaveric investigations.

    Science.gov (United States)

    Bates, Nathaniel A; Myer, Gregory D; Hewett, Timothy E

    2015-04-01

    Anterior cruciate ligament injuries are common, expensive to repair, and often debilitate athletic careers. Robotic manipulators have evaluated knee ligament biomechanics in cadaveric specimens, but face limitations such as accounting for variation in bony geometry between specimens that may influence dynamic motion pathways. This study examined individual anthropometric measures for significant linear relationships with in vivo kinematic and kinetic performance and determined their implications for robotic studies. Anthropometrics and 3D motion during a 31 cm drop vertical jump task were collected in high school female basketball players. Anthropometric measures demonstrated differential statistical significance in linear regression models relative to kinematic variables (p-range 0.20) relative to peak flexion moment, peak adduction moment, flexion moment range, abduction moment range, and internal rotation moment range. The current findings indicate that anthropometric measures are less associated with kinematics than with kinetics. Relative to the robotic manipulation of cadaveric limbs, the results do not support the need to normalize kinematic rotations relative to specimen dimensions.

  8. Kinematic space and wormholes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jian-dong [TianQin Research Center for Gravitational Physics, Sun Yat-sen University, Zhuhai 519082, Guangdong (China); Chen, Bin [Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, 5 Yiheyuan Rd, Beijing 100871 (China); Center for High Energy Physics, Peking University, 5 Yiheyuan Rd, Beijing 100871 (China)

    2017-01-23

    The kinematic space could play a key role in constructing the bulk geometry from dual CFT. In this paper, we study the kinematic space from geometric points of view, without resorting to differential entropy. We find that the kinematic space could be intrinsically defined in the embedding space. For each oriented geodesic in the Poincaré disk, there is a corresponding point in the kinematic space. This point is the tip of the causal diamond of the disk whose intersection with the Poincaré disk determines the geodesic. In this geometric construction, the causal structure in the kinematic space can be seen clearly. Moreover, we find that every transformation in the SL(2,ℝ) leads to a geodesic in the kinematic space. In particular, for a hyperbolic transformation defining a BTZ black hole, it is a timelike geodesic in the kinematic space. We show that the horizon length of the static BTZ black hole could be computed by the geodesic length of corresponding points in the kinematic space. Furthermore, we discuss the fundamental regions in the kinematic space for the BTZ blackhole and multi-boundary wormholes.

  9. Inverse Kinematics using Quaternions

    DEFF Research Database (Denmark)

    Henriksen, Knud; Erleben, Kenny; Engell-Nørregård, Morten

    In this project I describe the status of inverse kinematics research, with the focus firmly on the methods that solve the core problem. An overview of the different methods are presented Three common methods used in inverse kinematics computation have been chosen as subject for closer inspection....

  10. Kinematic Fitting of Detached Vertices

    Energy Technology Data Exchange (ETDEWEB)

    Mattione, Paul [Rice Univ., Houston, TX (United States)

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  11. Advances in robot kinematics

    CERN Document Server

    Khatib, Oussama

    2014-01-01

    The topics addressed in this book cover the whole range of kinematic analysis, synthesis and design and consider robotic systems possessing serial, parallel and cable driven mechanisms. The robotic systems range from being less than fully mobile to kinematically redundant to overconstrained.  The fifty-six contributions report the latest results in robot kinematics with emphasis on emerging areas such as design and control of humanoids or humanoid subsystems. The book is of interest to researchers wanting to bring their knowledge up to date regarding modern topics in one of the basic disciplines in robotics, which relates to the essential property of robots, the motion of mechanisms.

  12. Contact kinematics of biomimetic scales

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Ranajay; Ebrahimi, Hamid; Vaziri, Ashkan, E-mail: vaziri@coe.neu.edu [Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

    2014-12-08

    Dermal scales, prevalent across biological groups, considerably boost survival by providing multifunctional advantages. Here, we investigate the nonlinear mechanical effects of biomimetic scale like attachments on the behavior of an elastic substrate brought about by the contact interaction of scales in pure bending using qualitative experiments, analytical models, and detailed finite element (FE) analysis. Our results reveal the existence of three distinct kinematic phases of operation spanning linear, nonlinear, and rigid behavior driven by kinematic interactions of scales. The response of the modified elastic beam strongly depends on the size and spatial overlap of rigid scales. The nonlinearity is perceptible even in relatively small strain regime and without invoking material level complexities of either the scales or the substrate.

  13. A method to investigate the effect of shoe-hole size on surface marker movement when describing in-shoe joint kinematics using a multi-segment foot model.

    Science.gov (United States)

    Bishop, Chris; Arnold, John B; Fraysse, Francois; Thewlis, Dominic

    2015-01-01

    To investigate in-shoe foot kinematics, holes are often cut in the shoe upper to allow markers to be placed on the skin surface. However, there is currently a lack of understanding as to what is an appropriate size. This study aimed to demonstrate a method to assess whether different diameter holes were large enough to allow free motion of marker wands mounted on the skin surface during walking using a multi-segment foot model. Eighteen participants underwent an analysis of foot kinematics whilst walking barefoot and wearing shoes with different size holes (15 mm, 20mm and 25 mm). The analysis was conducted in two parts; firstly the trajectory of the individual skin-mounted markers were analysed in a 2D ellipse to investigate total displacement of each marker during stance. Secondly, a geometrical analysis was conducted to assess cluster deformation of the hindfoot and midfoot-forefoot segments. Where movement of the markers in the 15 and 20mm conditions were restricted, the marker movement in the 25 mm condition did not exceed the radius at any anatomical location. Despite significant differences in the isotropy index of the medial and lateral calcaneus markers between the 25 mm and barefoot conditions, the differences were due to the effect of footwear on the foot and not a result of the marker wands hitting the shoe upper. In conclusion, the method proposed and results can be used to increase confidence in the representativeness of joint kinematics with respect to in-shoe multi-segment foot motion during walking. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  14. Properties of kinematic singularities

    Energy Technology Data Exchange (ETDEWEB)

    Coley, A A [Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia B3H 3J5 (Canada); Hervik, S [Department of Mathematics and Natural Sciences, University of Stavanger, N-4036 Stavanger (Norway); Lim, W C [Albert-Einstein-Institut, Am Muehlenberg 1, D-14476 Potsdam (Germany); MacCallum, M A H, E-mail: aac@mathstat.dal.c, E-mail: sigbjorn.hervik@uis.n, E-mail: wclim@aei.mpg.d, E-mail: m.a.h.maccallum@qmul.ac.u [School of Mathematical Sciences, Queen Mary University of London, E1 4NS (United Kingdom)

    2009-11-07

    The locally rotationally symmetric tilted perfect fluid Bianchi type V cosmological model provides examples of future geodesically complete spacetimes that admit a 'kinematic singularity' at which the fluid congruence is inextendible but all frame components of the Weyl and Ricci tensors remain bounded. We show that for any positive integer n there are examples of Bianchi type V spacetimes admitting a kinematic singularity such that the covariant derivatives of the Weyl and Ricci tensors up to the nth order also stay bounded. We briefly discuss singularities in classical spacetimes.

  15. Teaching about Kinematics

    Science.gov (United States)

    Nelson, Jane Bray; Nelson, Jim

    2009-01-01

    Written by Jim and Jane Nelson, Teaching About Kinematics is the latest AAPT/PTRA resource book. Based on physics education research, the book provides teachers with the resources needed to introduce students to some of the fundamental building blocks of physics. It is a carefully thought-out, step-by-step laboratory-based introduction to the…

  16. The brown dwarf kinematics project

    Science.gov (United States)

    Faherty, Jackie K.

    2010-10-01

    Brown dwarfs are a recent addition to the plethora of objects studied in Astronomy. With theoretical masses between 13 and 75 MJupiter , they lack sustained stable Hydrogen burning so they never join the stellar main sequence. They have physical properties similar to both planets and low-mass stars so studies of their population inform on both. The distances and kinematics of brown dwarfs provide key statistical constraints on their ages, moving group membership, absolute brightnesses, evolutionary trends, and multiplicity. Yet, until my thesis, fundamental measurements of parallax and proper motion were made for only a relatively small fraction of the known population. To address this deficiency, I initiated the Brown Dwarf Kinematics (BDKP). Over the past four years I have re-imaged the majority of spectroscopically confirmed field brown dwarfs (or ultracool dwarfs---UCDs) and created the largest proper motion catalog for ultracool dwarfs to date. Using new astrometric information I examined population characteristics such as ages calculated from velocity dispersions and correlations between kinematics and colors. Using proper motions, I identified several new wide co-moving companions and investigated binding energy (and hence formation) limitations as well as the frequency of hierarchical companions. Concurrently over the past four years I have been conducting a parallax survey of 84 UCDs including those showing spectral signatures of youth, metal-poor brown dwarfs, and those within 20 pc of the Sun. Using absolute magnitude relations in J,H, and K, I identified overluminous binary candidates and investigated known flux-reversal binaries. Using current evolutionary models, I compared the MK vs J-K color magnitude diagram to model predictions and found that the low-surface gravity dwarfs are significantly red-ward and underluminous of predictions and a handful of late-type T dwarfs may require thicker clouds to account for their scatter.

  17. Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease

    Science.gov (United States)

    Wong, Min Ney; Murdoch, Bruce E.; Whelan, Brooke-Mai

    2012-01-01

    Background: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). Aims: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric…

  18. Quantum deformed magnon kinematics

    OpenAIRE

    Gómez, César; Hernández Redondo, Rafael

    2007-01-01

    The dispersion relation for planar N=4 supersymmetric Yang-Mills is identified with the Casimir of a quantum deformed two-dimensional kinematical symmetry, E_q(1,1). The quantum deformed symmetry algebra is generated by the momentum, energy and boost, with deformation parameter q=e^{2\\pi i/\\lambda}. Representing the boost as the infinitesimal generator for translations on the rapidity space leads to an elliptic uniformization with crossing transformations implemented through translations by t...

  19. Kinematic geometry of gearing

    CERN Document Server

    Dooner, David B

    2012-01-01

    Building on the first edition published in 1995 this new edition of Kinematic Geometry of Gearing has been extensively revised and updated with new and original material. This includes the methodology for general tooth forms, radius of torsure', cylinder of osculation, and cylindroid of torsure; the author has also completely reworked the '3 laws of gearing', the first law re-written to better parallel the existing 'Law of Gearing" as pioneered by Leonard Euler, expanded from Euler's original law to encompass non-circular gears and hypoid gears, the 2nd law of gearing describing a unique relat

  20. Kinematics and Dynamics of an Asymmetrical Parallel Robotic Wrist

    DEFF Research Database (Denmark)

    Wu, Guanglei

    2014-01-01

    This paper introduces an asymmetrical parallel robotic wrist, which can generate a decoupled unlimited-torsion motion and achieve high positioning accuracy. The kinematics, dexterity, and singularities of the manipulator are investigated to visualize the performance contours of the manipulator...

  1. Investigation of the nuclear matter density distributions of the exotic 12Be,14Be and 8B nuclei by elastic proton scattering in inverse kinematics

    International Nuclear Information System (INIS)

    Ilieva, Stoyanka

    2008-01-01

    In the current experiment, the differential cross sections for proton elastic scattering on the isotopes 7,9,10,11,12,14 Be and 8 B were measured. As results from the experiment, the absolute differential cross sections dσ/dt as a function of the four momentum transfer t were obtained. In this work the differential cross sections for elastic p- 12 Be, p- 14 Be and p- 8 B scattering at low t (t≤0.05(GeV/c) 2 ) are presented. The measured cross sections were analyzed within the Glauber multiple-scattering theory using different density parameterizations, and the nuclear matter density distributions and radii of the investigated isotopes were determined. The determined rms matter radius is 3.11±0.04±0.13 fm. In the case of the 12 Be nucleus the results showed an extended matter distribution as well. For this nucleus a matter radius of 2.82±0.03±0.12 fm was determined. An interesting result is that the free 12 Be nucleus behaves differently from the core of 14 Be and is much more extended than it. Preliminary experimental results for the isotope 8 B are also presented. An extended matter distribution was obtained (though much more compact as compared to the neutron halos). A proton halo structure was observed for the first time with the proton elastic scattering method. The deduced matter radius is 2.60±0.02±0.26 fm. Results from the feasibility studies of the EXL detector setup, performed at the present ESR storage ring, are presented. (orig.)

  2. Kinematic control of walking.

    Science.gov (United States)

    Lacquaniti, F; Ivanenko, Y P; Zago, M

    2002-10-01

    The planar law of inter-segmental co-ordination we described may emerge from the coupling of neural oscillators between each other and with limb mechanical oscillators. Muscle contraction intervenes at variable times to re-excite the intrinsic oscillations of the system when energy is lost. The hypothesis that a law of coordinative control results from a minimal active tuning of the passive inertial and viscoelastic coupling among limb segments is congruent with the idea that movement has evolved according to minimum energy criteria (1, 8). It is known that multi-segment motion of mammals locomotion is controlled by a network of coupled oscillators (CPGs, see 18, 33, 37). Flexible combination of unit oscillators gives rise to different forms of locomotion. Inter-oscillator coupling can be modified by changing the synaptic strength (or polarity) of the relative spinal connections. As a result, unit oscillators can be coupled in phase, out of phase, or with a variable phase, giving rise to different behaviors, such as speed increments or reversal of gait direction (from forward to backward). Supra-spinal centers may drive or modulate functional sets of coordinating interneurons to generate different walking modes (or gaits). Although it is often assumed that CPGs control patterns of muscle activity, an equally plausible hypothesis is that they control patterns of limb segment motion instead (22). According to this kinematic view, each unit oscillator would directly control a limb segment, alternately generating forward and backward oscillations of the segment. Inter-segmental coordination would be achieved by coupling unit oscillators with a variable phase. Inter-segmental kinematic phase plays the role of global control variable previously postulated for the network of central oscillators. In fact, inter-segmental phase shifts systematically with increasing speed both in man (4) and cat (38). Because this phase-shift is correlated with the net mechanical power

  3. Kinematic adjustments to seismic recordings

    Energy Technology Data Exchange (ETDEWEB)

    Telegin, A.N.; Levii, N.V.; Volovik, U.M.

    1981-01-01

    The introduction of kinematic adjustments by adding the displaced blocks is studied theoretically and in test seismograms. The advantage to this method resulting from the weight variation in the trace is demonstrated together with its kinematic drawback. A variation on the displaced block addition method that does not involve realignment of the travel time curves and that has improved amplitude characteristics is proposed.

  4. Kinematic Optimization in Birds, Bats and Ornithopters

    Science.gov (United States)

    Reichert, Todd

    Birds and bats employ a variety of advanced wing motions in the efficient production of thrust. The purpose of this thesis is to quantify the benefit of these advanced wing motions, determine the optimal theoretical wing kinematics for a given flight condition, and to develop a methodology for applying the results in the optimal design of flapping-wing aircraft (ornithopters). To this end, a medium-fidelity, combined aero-structural model has been developed that is capable of simulating the advanced kinematics seen in bird flight, as well as the highly non-linear structural deformations typical of high-aspect ratio wings. Five unique methods of thrust production observed in natural species have been isolated, quantified and thoroughly investigated for their dependence on Reynolds number, airfoil selection, frequency, amplitude and relative phasing. A gradient-based optimization algorithm has been employed to determined the wing kinematics that result in the minimum required power for a generalized aircraft or species in any given flight condition. In addition to the theoretical work, with the help of an extended team, the methodology was applied to the design and construction of the world's first successful human-powered ornithopter. The Snowbird Human-Powered Ornithopter, is used as an example aircraft to show how additional design constraints can pose limits on the optimal kinematics. The results show significant trends that give insight into the kinematic operation of natural species. The general result is that additional complexity, whether it be larger twisting deformations or advanced wing-folding mechanisms, allows for the possibility of more efficient flight. At its theoretical optimum, the efficiency of flapping-wings exceeds that of current rotors and propellers, although these efficiencies are quite difficult to achieve in practice.

  5. Kinematic aspects of pion-nucleus elastic scattering

    International Nuclear Information System (INIS)

    Weiss, D.L.; Ernst, D.J.

    1982-01-01

    The inclusion of relativistic kinematics in the theory of elastic scattering of pions from nuclei is examined. The investigation is performed in the context of the first order impulse approximation which incorporates the following features: (1) Relative momentum are defined according to relativistic theories consistent with time reversal invariance. (2) The two-nucleon interaction is a new, multichannel, separable potential model consistent with the most recent data derived from a recent nonpotential model of Ernst and Johnson. (3) The recoil of the pion-nucleon interacting pair and its resultant nonlocality are included. (4) The Fermi integral is treated by an optimal factorization approximation. It is shown how a careful definition of an intrinsic target density leads to an unambiguous method for including the recoil of the target. The target recoil corrections are found to be large for elastic scattering from 4 He and not negligible for scattering from 12 C. Relativistic potential theory kinematics, kinematics which result from covariant reduction approaches, and kinematics which result from replacing masses by energies in nonrelativistic formulas are compared. The relativistic potential theory kinematics and covariant reduction kinematics are shown to produce different elastic scattering at all pion energies examined (T/sub π/<300 MeV). Simple extensions of nonrelativistic kinematics are found to be reasonable approximations to relativistic potential theory

  6. Kinematic measurements using an infrared sensor

    International Nuclear Information System (INIS)

    Marinho, F; Paulucci, L

    2016-01-01

    The use of an infrared sensor as a new alternative to measure position as a function of time in kinematic experiments was investigated using a microcontroller as the data acquisition and control device. These are versatile sensors that offer advantages over typical ultrasound devices. The setup described in this paper enables students to develop their own experiments, promoting opportunities for learning physical concepts such as the different types of forces that can act on a body (gravitational, elastic, drag, etc) and the resulting types of movements with good sensitivity within the 4–30 cm range. As a proof of concept we also present the application of a prototype designed to record the kinematics of mass-spring systems. (paper)

  7. Elementary introduction to relativistic kinematics

    International Nuclear Information System (INIS)

    Gerber, H.J.

    1979-01-01

    This paper includes the most important results and applications of the theory of special relativity to high energy phenomena; it provides an analysis of the kinematics of particle decays and reactions as well as an introduction to the Lorentz group

  8. Overground-Propulsion Kinematics and Acceleration in Elite Wheelchair Rugby.

    Science.gov (United States)

    Haydon, David S; Pinder, Ross A; Grimshaw, Paul N; Robertson, William S P

    2018-02-01

    Maximal acceleration from standstill has been identified as a key performance indicator in wheelchair rugby; however, the impact of classification and kinematic variables on performance has received limited attention. This study aimed to investigate kinematic variables during maximal acceleration, with level of activity limitation accounted for using sport-classification scores. Based on their sporting classification scores, which reflect combined trunk, arm, and hand function, 25 elite wheelchair rugby players were analyzed in high-, mid-, and low-point groups before completing five 5-m sprints from a stationary position. Inertial measurement units and video analysis were used to monitor key kinematic variables. Significant differences in kinematic variables were evident across the classification groups, particularly for the first stroke-contact angle (1-way ANOVA F 2,122  = 51.5, P propulsion approaches exist across classification groups, with this information potentially informing individual wheelchair setups and training programs.

  9. Kinematics in special and general relativity

    International Nuclear Information System (INIS)

    Woodside, R.W.M.

    1979-05-01

    This thesis investigates the problem of motion for extended bodies from the viewpoint of classical field theory, where the classical field is the body's energy-momentum or matter tensor. In special relativity a symmetric and divergence-free matter tensor combined with inertial frames is used to generate a kinematics for extended bodies. In general relativity the author suggests an analogous kinematics and applies it to the simplest non-trivial example of static, spherical stars, looking for special sets of vector fields whose matter currents are conserved. Such a set of ten vector fields defines a special frame, and integrals of the conserved matter currents define ten momenta whcih give the kinematics. Application of de Rham cohomology theory shows that the conserved matter currents for isolated bodies will have mechanical potentials which enable the momenta to be found from flux integrals evaluated in the vacuum region surrounding the body. These potentials contain the full Riemann curvature, allowing a body's general relativistic momenta to be determined by its vacuum graviational field

  10. Effect of suspension kinematic on 14 DOF vehicle model

    Science.gov (United States)

    Wongpattananukul, T.; Chantharasenawong, C.

    2017-12-01

    Computer simulations play a major role in shaping modern science and engineering. They reduce time and resource consumption in new studies and designs. Vehicle simulations have been studied extensively to achieve a vehicle model used in minimum lap time solution. Simulation result accuracy depends on the abilities of these models to represent real phenomenon. Vehicles models with 7 degrees of freedom (DOF), 10 DOF and 14 DOF are normally used in optimal control to solve for minimum lap time. However, suspension kinematics are always neglected on these models. Suspension kinematics are defined as wheel movements with respect to the vehicle body. Tire forces are expressed as a function of wheel slip and wheel position. Therefore, the suspension kinematic relation is appended to the 14 DOF vehicle model to investigate its effects on the accuracy of simulate trajectory. Classical 14 DOF vehicle model is chosen as baseline model. Experiment data is collected from formula student style car test runs as baseline data for simulation and comparison between baseline model and model with suspension kinematic. Results show that in a single long turn there is an accumulated trajectory error in baseline model compared to model with suspension kinematic. While in short alternate turns, the trajectory error is much smaller. These results show that suspension kinematic had an effect on the trajectory simulation of vehicle. Which optimal control that use baseline model will result in inaccuracy control scheme.

  11. Kinematic sensitivity of robot manipulators

    Science.gov (United States)

    Vuskovic, Marko I.

    1989-01-01

    Kinematic sensitivity vectors and matrices for open-loop, n degrees-of-freedom manipulators are derived. First-order sensitivity vectors are defined as partial derivatives of the manipulator's position and orientation with respect to its geometrical parameters. The four-parameter kinematic model is considered, as well as the five-parameter model in case of nominally parallel joint axes. Sensitivity vectors are expressed in terms of coordinate axes of manipulator frames. Second-order sensitivity vectors, the partial derivatives of first-order sensitivity vectors, are also considered. It is shown that second-order sensitivity vectors can be expressed as vector products of the first-order sensitivity vectors.

  12. Latest Advances in Robot Kinematics

    CERN Document Server

    Husty, Manfred

    2012-01-01

    This book is  of interest to researchers inquiring about modern topics and methods in the kinematics, control and design of robotic manipulators. It considers the full range of robotic systems, including serial, parallel and cable driven manipulators, both planar and spatial. The systems range from being less than fully mobile to kinematically redundant to overconstrained. In addition to recognized areas, this book also presents recent advances in emerging areas such as the design and control of humanoids and humanoid subsystems, and the analysis, modeling and simulation of human body motions, as well as the mobility analysis of protein molecules and the development of machines which incorporate man.

  13. Kinematics of machinery through hyperworks

    CERN Document Server

    Rao, J S

    2011-01-01

    Using animations, this book explains the theory of machines concepts and the evolution of Kinematics. The book adopts HyperWorks MotionSolve to perform the analysis and visualizations, though the book is independent of the requirement of any software.

  14. General analytical shakedown solution for structures with kinematic hardening materials

    Science.gov (United States)

    Guo, Baofeng; Zou, Zongyuan; Jin, Miao

    2016-09-01

    The effect of kinematic hardening behavior on the shakedown behaviors of structure has been investigated by performing shakedown analysis for some specific problems. The results obtained only show that the shakedown limit loads of structures with kinematic hardening model are larger than or equal to those with perfectly plastic model of the same initial yield stress. To further investigate the rules governing the different shakedown behaviors of kinematic hardening structures, the extended shakedown theorem for limited kinematic hardening is applied, the shakedown condition is then proposed, and a general analytical solution for the structural shakedown limit load is thus derived. The analytical shakedown limit loads for fully reversed cyclic loading and non-fully reversed cyclic loading are then given based on the general solution. The resulting analytical solution is applied to some specific problems: a hollow specimen subjected to tension and torsion, a flanged pipe subjected to pressure and axial force and a square plate with small central hole subjected to biaxial tension. The results obtained are compared with those in literatures, they are consistent with each other. Based on the resulting general analytical solution, rules governing the general effects of kinematic hardening behavior on the shakedown behavior of structure are clearly.

  15. Inverse Kinematics With Closed Form Solution For Denso Robot Manipulator

    OpenAIRE

    Ikhsan Eka Prasetia; Trihastuti Agustinah

    2015-01-01

    In this paper, the forward kinematics and inverse kinematics used on the Denso robot manipulator which has a 6-DOF. The forward kinematics will result in the desired position by end-effector, while inverse kinematics produce angel on each joint. Inverse kinematics problem are very difficult, therefor to obtain the solution of inverse kinematics using closed form solution with geometry approach. The simulation result obtained from forward kinematics and inverse kinematics is determining desire...

  16. Suspension kinematic analysis of UTeM’s FV Malaysia electric vehicle racing car

    NARCIS (Netherlands)

    Abdul Manaf, M.Z.; Latif, M.F.A.; Razak, M.S.A.; Hassan, M.Z.B.; Rosley, M.I.F.

    2016-01-01

    The purpose of this paper is to investigate the kinematic performance of students’ racing car, namely UTeM’s FV Malaysia Electric Vehicle. An elasto-kinematic analysis approach is used to predict the car’s performance during straight line drive and curvature drive. Two suspension design factors

  17. Kinematic Model of NAO Humanoid Robot

    Directory of Open Access Journals (Sweden)

    Miloš D. Jovanović

    2014-06-01

    Full Text Available This paper presents synthesis of kinematic model of NAO humanoid robot of Aldebaran Robotics. NAO humanoid robot has complex kinematic structure with 25 active degrees of freedom (DOF. Humanoid system is formed through 5 mutually depended kinematic chains. After that we applied standard aspects of kinematic chains synthesis and Denavit-Hartenberg parameters of each of 5 chains of robotic structure were introduced. Also, mutual relationships between chains were described, as well as their physical and structural dependence. Generated kinematic model will be the starting point for further dynamical modeling of NAO humanoid robot and motion synthesis on actual platform.

  18. pynoddy 1.0: an experimental platform for automated 3-D kinematic and potential field modelling

    Science.gov (United States)

    Florian Wellmann, J.; Thiele, Sam T.; Lindsay, Mark D.; Jessell, Mark W.

    2016-03-01

    We present a novel methodology for performing experiments with subsurface structural models using a set of flexible and extensible Python modules. We utilize the ability of kinematic modelling techniques to describe major deformational, tectonic, and magmatic events at low computational cost to develop experiments testing the interactions between multiple kinematic events, effect of uncertainty regarding event timing, and kinematic properties. These tests are simple to implement and perform, as they are automated within the Python scripting language, allowing the encapsulation of entire kinematic experiments within high-level class definitions and fully reproducible results. In addition, we provide a link to geophysical potential-field simulations to evaluate the effect of parameter uncertainties on maps of gravity and magnetics. We provide relevant fundamental information on kinematic modelling and our implementation, and showcase the application of our novel methods to investigate the interaction of multiple tectonic events on a pre-defined stratigraphy, the effect of changing kinematic parameters on simulated geophysical potential fields, and the distribution of uncertain areas in a full 3-D kinematic model, based on estimated uncertainties in kinematic input parameters. Additional possibilities for linking kinematic modelling to subsequent process simulations are discussed, as well as additional aspects of future research. Our modules are freely available on github, including documentation and tutorial examples, and we encourage the contribution to this project.

  19. Sex Differences in Tibiocalcaneal Kinematics

    Directory of Open Access Journals (Sweden)

    Sinclair Jonathan

    2014-08-01

    Full Text Available Purpose. Female runners typically suffer more from chronic running injuries than age-matched males, although the exact biome-chanical mechanisms behind the increased susceptibility of female runners are unknown. This study aimed to compare sex differences in tibiocalcaneal kinematics during the stance phase of running. Methods. Twenty male and twenty female participants ran at 4.0 m · s–1. Tibiocalcaneal kinematics were measured using an eight-camera motion analysis system and compared using independent samples t tests. Results. Peak eversion and tibial internal rotation angles were shown to be significantly greater in female runners. Conclusions. based on these observations, it was determined that female runners may be at increased risk from chronic injury development in relation to excessive tibiocalcaneal motions in the coronal and transverse planes.

  20. Kinematic analysis of parallel manipulators by algebraic screw theory

    CERN Document Server

    Gallardo-Alvarado, Jaime

    2016-01-01

    This book reviews the fundamentals of screw theory concerned with velocity analysis of rigid-bodies, confirmed with detailed and explicit proofs. The author additionally investigates acceleration, jerk, and hyper-jerk analyses of rigid-bodies following the trend of the velocity analysis. With the material provided in this book, readers can extend the theory of screws into the kinematics of optional order of rigid-bodies. Illustrative examples and exercises to reinforce learning are provided. Of particular note, the kinematics of emblematic parallel manipulators, such as the Delta robot as well as the original Gough and Stewart platforms are revisited applying, in addition to the theory of screws, new methods devoted to simplify the corresponding forward-displacement analysis, a challenging task for most parallel manipulators. Stands as the only book devoted to the acceleration, jerk and hyper-jerk (snap) analyses of rigid-body by means of screw theory; Provides new strategies to simplify the forward kinematic...

  1. Pythagoras Theorem and Relativistic Kinematics

    Science.gov (United States)

    Mulaj, Zenun; Dhoqina, Polikron

    2010-01-01

    In two inertial frames that move in a particular direction, may be registered a light signal that propagates in an angle with this direction. Applying Pythagoras theorem and principles of STR in both systems, we can derive all relativistic kinematics relations like the relativity of simultaneity of events, of the time interval, of the length of objects, of the velocity of the material point, Lorentz transformations, Doppler effect and stellar aberration.

  2. Kinematic top analyses at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Grassmann, H.; CDF Collaboration

    1995-03-01

    We present an update of the top quark analysis using kinematic techniques in p{bar p} collisions at {radical}s = 1.8 TeV with the Collider Detector at Fermilab (CDF). We reported before on a study which used 19.3 pb{sup {minus}1} of data from the 1992--1993 collider run, but now we use a larger data sample of 67 pb{sup {minus}1}. First, we analyze the total transverse energy of the hard collision in W+{ge}3 jet events, showing the likely presence of a t{bar t} component in the event sample. Next, we compare in more detail the kinematic structure of W+ {ge}3 jet events with expectations for top pair production and with background processes, predominantly direct W+ jet production. We again find W+ {ge} 3 jet events which cannot be explained in terms of background, but show kinematic features as expected from top. These events also show evidence for beauty quarks, in agreement with expectations from top, but not compatible with expectations from backgrounds. The findings confirm the observation of top events made earlier in the data of the 1992--1993 collider run.

  3. Effect of balance exercise on selected kinematic gait variables in ...

    African Journals Online (AJOL)

    The purpose of this study was to investigate the effect of balance exercise on some selected kinematic gait parameters in patients with knee joint osteoarthritis. Forty subjects (18 men and 22 women) participated in the study.They were divided into two groups: Group 1 (experimental) that was treated with balance exercises, ...

  4. Can co-activation reduce kinematic variability? A simulation study.

    NARCIS (Netherlands)

    Selen, L.P.J.; Beek, P.J.; van Dieen, J.H.

    2005-01-01

    Impedance modulation has been suggested as a means to suppress the effects of internal 'noise' on movement kinematics. We investigated this hypothesis in a neuro-musculo-skeletal model. A prerequisite is that the muscle model produces realistic force variability. We found that standard Hill-type

  5. Of gluons and gravitons. Exploring color-kinematics duality

    International Nuclear Information System (INIS)

    Isermann, Reinke Sven

    2013-06-01

    In this thesis color-kinematics duality will be investigated. This duality is a statement about the kinematical dependence of a scattering amplitude in Yang-Mills gauge theories obeying group theoretical relations similar to that of the color gauge group. The major consequence of this duality is that gravity amplitudes can be related to a certain double copy of gauge theory amplitudes. The main focus of this thesis is on exploring the foundations of color-kinematics duality and its consequences. It is shown how color-kinematics duality can be made manifest at the one-loop level for rational amplitudes. A Lagrangian-based argument will be given for the validity of the double copy construction for these amplitudes including explicit examples at four points. Secondly, it is studied how color-kinematics duality can be used to improve powercounting in gravity theories. To this end the duality is reformulated in terms of linear maps. It is shown as an example how this can be used to derive the large BCFW shift behavior of a gravity integrand constructed through the duality to any loop order up to subtleties inherent to the duality that is addressed. As it becomes clear the duality implies massive cancellations with respect to the usual powercounting of Feynman graphs indicating that gravity theories are much better behaved than naively expected. As another example the linear map approach will be used to investigate the question of UV-finiteness of N=8 supergravity, and it is seen that the amount of cancellations depends on the exact implementation of the duality at loop level. Lastly, color-kinematics duality is considered from a Feynman-graph perspective reproducing some of the results of the earlier chapters thus giving non-trivial evidence for the duality at the loop level from a different perspective.

  6. Of gluons and gravitons. Exploring color-kinematics duality

    Energy Technology Data Exchange (ETDEWEB)

    Isermann, Reinke Sven

    2013-06-15

    In this thesis color-kinematics duality will be investigated. This duality is a statement about the kinematical dependence of a scattering amplitude in Yang-Mills gauge theories obeying group theoretical relations similar to that of the color gauge group. The major consequence of this duality is that gravity amplitudes can be related to a certain double copy of gauge theory amplitudes. The main focus of this thesis is on exploring the foundations of color-kinematics duality and its consequences. It is shown how color-kinematics duality can be made manifest at the one-loop level for rational amplitudes. A Lagrangian-based argument will be given for the validity of the double copy construction for these amplitudes including explicit examples at four points. Secondly, it is studied how color-kinematics duality can be used to improve powercounting in gravity theories. To this end the duality is reformulated in terms of linear maps. It is shown as an example how this can be used to derive the large BCFW shift behavior of a gravity integrand constructed through the duality to any loop order up to subtleties inherent to the duality that is addressed. As it becomes clear the duality implies massive cancellations with respect to the usual powercounting of Feynman graphs indicating that gravity theories are much better behaved than naively expected. As another example the linear map approach will be used to investigate the question of UV-finiteness of N=8 supergravity, and it is seen that the amount of cancellations depends on the exact implementation of the duality at loop level. Lastly, color-kinematics duality is considered from a Feynman-graph perspective reproducing some of the results of the earlier chapters thus giving non-trivial evidence for the duality at the loop level from a different perspective.

  7. A KINEMATIC STUDY OF FINSWIMMING AT SURFACE

    Directory of Open Access Journals (Sweden)

    Pier-Giorgio Zanone

    2004-06-01

    Full Text Available Finswimming is a sport of speed practiced on the surface or underwater, in which performance is based on whole-body oscillations. The present study investigated the undulatory motion performed by finswimmers at the surface. This study aiming to analyze the influence of the interaction of gender, practice level, and race distance on selected kinematic parameters. Six elite and six novices finswimmers equipped with joints markers (wrist, elbow, shoulder, hip, knee, and ankle were recorded in the sagittal plane. The position of these anatomical marks was digitized at 50 Hz. An automated motion analysis software yielded velocity, vertical amplitude, frequency, and angular position. Results showed that stroke frequency decreased whereas the mean amplitude of all joints increased with increasing race distance (p < 0.01. Mean joint amplitude for the upper limbs (wrist, elbow and shoulder was smaller for experts than for novices. Whereas that of the ankle was larger, so that the oscillation amplitude increased from shoulder to ankle. Elite male finswimmers were pitching more acutely than female. Moreover, elite male finswimmers showed a smaller knee bending than novices and than elite females (p < 0.01. This indicated that elite male finswimmers attempt to reduce drag forces thanks to a weak knee bending and a low upper limbs pitch. To sum up, gender, expertise, and race distance affect the performance and its kinematics in terms frontal drag. Expertise in finswimming requires taking advantage of the mechanical constraints pertaining to hydrodynamic constraints in order to optimize performance

  8. Inverse Kinematic Analysis Of A Quadruped Robot

    Directory of Open Access Journals (Sweden)

    Muhammed Arif Sen

    2017-09-01

    Full Text Available This paper presents an inverse kinematics program of a quadruped robot. The kinematics analysis is main problem in the manipulators and robots. Dynamic and kinematic structures of quadruped robots are very complex compared to industrial and wheeled robots. In this study inverse kinematics solutions for a quadruped robot with 3 degrees of freedom on each leg are presented. Denavit-Hartenberg D-H method are used for the forward kinematic. The inverse kinematic equations obtained by the geometrical and mathematical methods are coded in MATLAB. And thus a program is obtained that calculate the legs joint angles corresponding to desired various orientations of robot and endpoints of legs. Also the program provides the body orientations of robot in graphical form. The angular positions of joints obtained corresponding to desired different orientations of robot and endpoints of legs are given in this study.

  9. Kinematics Control and Analysis of Industrial Robot

    Science.gov (United States)

    Zhu, Tongbo; Cai, Fan; Li, Yongmei; Liu, Wei

    2018-03-01

    The robot’s development present situation, basic principle and control system are introduced briefly. Research is mainly focused on the study of the robot’s kinematics and motion control. The structural analysis of a planar articulated robot (SCARA) robot is presented,the coordinate system is established to obtain the position and orientation matrix of the end effector,a method of robot kinematics analysis based on homogeneous transformation method is proposed, and the kinematics solution of the robot is obtained.Establishment of industrial robot’s kinematics equation and formula for positive kinematics by example. Finally,the kinematic analysis of this robot was verified by examples.It provides a basis for structural design and motion control.It has active significance to promote the motion control of industrial robot.

  10. Nuclear reaction studies using inverse kinematics

    International Nuclear Information System (INIS)

    Shapira, D.

    1985-01-01

    Reaction studies with reversed kinematics refer to studies of nuclear reactions induced by a heavy projectile colliding with lighter target nuclei. The technique of using reversed kinematics is costly in terms of the available center-of-mass energy. Most of the projectile's energy goes into forward motion of the reaction products in the laboratory system. Examples are presented where the use of reversed kinematics techniques has provided new information on certain reaction processes. A list of kinematic properties and advantages they may afford is shown. Clearly the possible studies listed can be done without using reversed kinematics but because of the difficulty associated with some of these studies they were never performed until more energetic heavier beams have become available and the reversed kinematics technique was utilized

  11. Kinematic correction for roller skewing

    Science.gov (United States)

    Savage, M.; Loewenthal, S. H.

    1980-01-01

    A theory of kinematic stabilization of rolling cylinders is developed for high-speed cylindrical roller bearings. This stabilization requires race and roller crowning to product changes in the rolling geometry as the roller shifts axially. These changes put a reverse skew in the rolling elements by changing the rolling taper. Twelve basic possible bearing modifications are identified in this paper. Four have single transverse convex curvature in the rollers while eight have rollers with compound transverse curvature composed of a central cylindrical band of constant radius surrounded by symmetric bands with both slope and transverse curvature.

  12. Inverse kinematics of OWI-535 robotic arm

    OpenAIRE

    DEBENEC, PRIMOŽ

    2015-01-01

    The thesis aims to calculate the inverse kinematics for the OWI-535 robotic arm. The calculation of the inverse kinematics determines the joint parameters that provide the right pose of the end effector. The pose consists of the position and orientation, however, we will focus only on the second one. Due to arm limitations, we have created our own type of the calculation of the inverse kinematics. At first we have derived it only theoretically, and then we have transferred the derivation into...

  13. Design of a Two-Step Calibration Method of Kinematic Parameters for Serial Robots

    Science.gov (United States)

    WANG, Wei; WANG, Lei; YUN, Chao

    2017-03-01

    Serial robots are used to handle workpieces with large dimensions, and calibrating kinematic parameters is one of the most efficient ways to upgrade their accuracy. Many models are set up to investigate how many kinematic parameters can be identified to meet the minimal principle, but the base frame and the kinematic parameter are indistinctly calibrated in a one-step way. A two-step method of calibrating kinematic parameters is proposed to improve the accuracy of the robot's base frame and kinematic parameters. The forward kinematics described with respect to the measuring coordinate frame are established based on the product-of-exponential (POE) formula. In the first step the robot's base coordinate frame is calibrated by the unit quaternion form. The errors of both the robot's reference configuration and the base coordinate frame's pose are equivalently transformed to the zero-position errors of the robot's joints. The simplified model of the robot's positioning error is established in second-power explicit expressions. Then the identification model is finished by the least square method, requiring measuring position coordinates only. The complete subtasks of calibrating the robot's 39 kinematic parameters are finished in the second step. It's proved by a group of calibration experiments that by the proposed two-step calibration method the average absolute accuracy of industrial robots is updated to 0.23 mm. This paper presents that the robot's base frame should be calibrated before its kinematic parameters in order to upgrade its absolute positioning accuracy.

  14. Quantifying meniscal kinematics in dogs.

    Science.gov (United States)

    Park, Brian H; Banks, Scott A; Pozzi, Antonio

    2017-11-06

    The dog has been used extensively as an experimental model to study meniscal treatments such as meniscectomy, meniscal repair, transplantation, and regeneration. However, there is very little information on meniscal kinematics in the dog. This study used MR imaging to quantify in vitro meniscal kinematics in loaded dog knees in four distinct poses: extension, flexion, internal, and external rotation. A new method was used to track the meniscal poses along the convex and posteriorly tilted tibial plateau. Meniscal displacements were large, displacing 13.5 and 13.7 mm posteriorly on average for the lateral and medial menisci during flexion (p = 0.90). The medial anterior horn and lateral posterior horns were the most mobile structures, showing average translations of 15.9 and 15.1 mm, respectively. Canine menisci are highly mobile and exhibit movements that correlate closely with the relative tibiofemoral positions. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  15. Kinematic Modeling of Distant Galaxies

    Directory of Open Access Journals (Sweden)

    Kipper Rain

    2012-12-01

    Full Text Available Evolution of galaxies is one of the most actual topics in astrophysics. Among the most important factors determining the evolution are two galactic components which are difficult or even impossible to detect optically: the gaseous disks and the dark matter halo. We use deep Hubble Space Telescope images to construct a two-component (bulge + disk model for stellar matter distribution of galaxies. Properties of the galactic components are derived using a three-dimensional galaxy modeling software, which also estimates disk thickness and inclination angle. We add a gas disk and a dark matter halo and use hydrodynamical equations to calculate gas rotation and dispersion profiles in the resultant gravitational potential. We compare the kinematic profiles with the Team Keck Redshift Survey observations. In this pilot study, two galaxies are analyzed deriving parameters for their stellar components; both galaxies are found to be disk-dominated. Using the kinematical model, the gas mass and stellar mass ratio in the disk are estimated.

  16. Ballistic representation for kinematic access

    Science.gov (United States)

    Alfano, Salvatore

    2011-01-01

    This work uses simple two-body orbital dynamics to initially determine the kinematic access for a ballistic vehicle. Primarily this analysis was developed to assess when a rocket body might conjunct with an orbiting satellite platform. A family of access opportunities can be represented as a volume for a specific rocket relative to its launch platform. Alternately, the opportunities can be represented as a geographical footprint relative to aircraft or satellite position that encompasses all possible launcher locations for a specific rocket. A thrusting rocket is treated as a ballistic vehicle that receives all its energy at launch and follows a coasting trajectory. To do so, the rocket's burnout energy is used to find its equivalent initial velocity for a given launcher's altitude. Three kinematic access solutions are then found that account for spherical Earth rotation. One solution finds the maximum range for an ascent-only trajectory while another solution accommodates a descending trajectory. In addition, the ascent engagement for the descending trajectory is used to depict a rapid access scenario. These preliminary solutions are formulated to address ground-, sea-, or air-launched vehicles.

  17. Effects of load on good morning kinematics and EMG activity

    Directory of Open Access Journals (Sweden)

    Andrew David Vigotsky

    2015-01-01

    Full Text Available Many strength and conditioning coaches utilize the good morning (GM to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flexion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises.

  18. Primate Anatomy, Kinematics, and Principles for Humanoid Design

    Science.gov (United States)

    Ambrose, Robert O.; Ambrose, Catherine G.

    2004-01-01

    The primate order of animals is investigated for clues in the design of Humanoid Robots. The pursuit is directed with a theory that kinematics, musculature, perception, and cognition can be optimized for specific tasks by varying the proportions of limbs, and in particular, the points of branching in kinematic trees such as the primate skeleton. Called the Bifurcated Chain Hypothesis, the theory is that the branching proportions found in humans may be superior to other animals and primates for the tasks of dexterous manipulation and other human specialties. The primate taxa are defined, contemporary primate evolution hypotheses are critiqued, and variations within the order are noted. The kinematic branching points of the torso, limbs and fingers are studied for differences in proportions across the order, and associated with family and genus capabilities and behaviors. The human configuration of a long waist, long neck, and short arms is graded using a kinematic workspace analysis and a set of design axioms for mobile manipulation robots. It scores well. The re emergence of the human waist, seen in early Prosimians and Monkeys for arboreal balance, but lost in the terrestrial Pongidae, is postulated as benefiting human dexterity. The human combination of an articulated waist and neck will be shown to enable the use of smaller arms, achieving greater regions of workspace dexterity than the larger limbs of Gorillas and other Hominoidea.

  19. Kinematically Decoupled Cores in Dwarf (Elliptical) Galaxies

    NARCIS (Netherlands)

    Toloba, E.; Peletier, R. F.; Guhathakurta, P.; van de Ven, G.; Boissier, S.; Boselli, A.; Brok, M. d.; Falcón-Barroso, J.; Hensler, G.; Janz, J.; Laurikainen, E.; Lisker, T.; Paudel, S.; Ryś, A.; Salo, H.

    An overview is given of what we know about the frequency of kinematically decoupled cores in dwarf elliptical galaxies. New observations show that kinematically decoupled cores happen just as often in dwarf elliptical as in ordinary early-type galaxies. This has important consequences for the

  20. Kinematic models of extensional structures

    International Nuclear Information System (INIS)

    Groshong, R.H. Jr.

    1990-01-01

    This paper discusses kinematic models that can relate faults of different types and different positions within a single dynamic system and thereby offer the potential to explain the disparate seismic activity characteristic of extensional terrains. The major styles are full grabens, half grabens, domino blocks, and glide-block systems. Half grabens, the most likely models for Basin and Range structure, are formed above a master fault of decreasing dip with depth and a hangingwall that deforms as it passes over the curved fault. Second-order normal faults, typically domino style, accommodate the required hangingwall deformation. According to the author low-angle detachment faults are consistent with the evidence of seismicity only on high-angle faults if the hangingwall of the detachment is broken by multiple half-graben systems

  1. The gait standard deviation, a single measure of kinematic variability.

    Science.gov (United States)

    Sangeux, Morgan; Passmore, Elyse; Graham, H Kerr; Tirosh, Oren

    2016-05-01

    Measurement of gait kinematic variability provides relevant clinical information in certain conditions affecting the neuromotor control of movement. In this article, we present a measure of overall gait kinematic variability, GaitSD, based on combination of waveforms' standard deviation. The waveform standard deviation is the common numerator in established indices of variability such as Kadaba's coefficient of multiple correlation or Winter's waveform coefficient of variation. Gait data were collected on typically developing children aged 6-17 years. Large number of strides was captured for each child, average 45 (SD: 11) for kinematics and 19 (SD: 5) for kinetics. We used a bootstrap procedure to determine the precision of GaitSD as a function of the number of strides processed. We compared the within-subject, stride-to-stride, variability with the, between-subject, variability of the normative pattern. Finally, we investigated the correlation between age and gait kinematic, kinetic and spatio-temporal variability. In typically developing children, the relative precision of GaitSD was 10% as soon as 6 strides were captured. As a comparison, spatio-temporal parameters required 30 strides to reach the same relative precision. The ratio stride-to-stride divided by normative pattern variability was smaller in kinematic variables (the smallest for pelvic tilt, 28%) than in kinetic and spatio-temporal variables (the largest for normalised stride length, 95%). GaitSD had a strong, negative correlation with age. We show that gait consistency may stabilise only at, or after, skeletal maturity. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Effects of marathon fatigue on running kinematics and economy

    OpenAIRE

    Nicol , Caroline; Komi , P V; Marconnet , P

    1991-01-01

    International audience; The influence of marathon fatigue on both running kinematics and economy was investigated with 8 subjects. The measurements included a treadmill test at 3 steady submaximal speeds performed before and after the marathon. One complete left leg cycle was videotaped at 100 Hz from the left side at each speed. The analysis included contact time (braking and push-off') and flight time as well as displacements and angular velocities of the left hip and knee. This analysis wa...

  3. COMPARISON STUDY OF EXPERIMENTS AND PREDICTIONS OF WAVE KINEMATICS FOR ROGUE WAVE

    Directory of Open Access Journals (Sweden)

    Hae Jin Choi

    2018-01-01

    Full Text Available To investigate the wave kinematics under the rogue wave crest, a series of experiments were performed in 2-D wave tank with the application of PIV technique to measure the velocities under the free surface. Three different prediction methods of linear extrapolation, Wheeler stretching, and modified stretching were applied to estimate water wave kinematics and compared with PIV experimental results under the highest wave crest of irregular wave trains satisfying with rogue wave criteria. Also, the cut-off frequency dependence for three prediction methods was investigated with varying spectral peak frequencies to estimate wave kinematics including velocities and accelerations in horizontal and vertical directions. It was suggested that the cut-off frequency for the reasonable prediction of the wave kinematics under the rogue wave crest could be chosen three times of spectral peak wave frequency for the linear extrapolation and higher frequency than four times of spectral peak wave frequency for Wheeler stretching and modified stretching method.

  4. Digital Hardware Realization of Forward and Inverse Kinematics for a Five-Axis Articulated Robot Arm

    Directory of Open Access Journals (Sweden)

    Bui Thi Hai Linh

    2015-01-01

    Full Text Available When robot arm performs a motion control, it needs to calculate a complicated algorithm of forward and inverse kinematics which consumes much CPU time and certainty slows down the motion speed of robot arm. Therefore, to solve this issue, the development of a hardware realization of forward and inverse kinematics for an articulated robot arm is investigated. In this paper, the formulation of the forward and inverse kinematics for a five-axis articulated robot arm is derived firstly. Then, the computations algorithm and its hardware implementation are described. Further, very high speed integrated circuits hardware description language (VHDL is applied to describe the overall hardware behavior of forward and inverse kinematics. Additionally, finite state machine (FSM is applied for reducing the hardware resource usage. Finally, for verifying the correctness of forward and inverse kinematics for the five-axis articulated robot arm, a cosimulation work is constructed by ModelSim and Simulink. The hardware of the forward and inverse kinematics is run by ModelSim and a test bench which generates stimulus to ModelSim and displays the output response is taken in Simulink. Under this design, the forward and inverse kinematics algorithms can be completed within one microsecond.

  5. Inverse Kinematics With Closed Form Solution For Denso Robot Manipulator

    Directory of Open Access Journals (Sweden)

    Ikhsan Eka Prasetia

    2015-03-01

    Full Text Available In this paper, the forward kinematics and inverse kinematics used on the Denso robot manipulator which has a 6-DOF. The forward kinematics will result in the desired position by end-effector, while inverse kinematics produce angel on each joint. Inverse kinematics problem are very difficult, therefor to obtain the solution of inverse kinematics using closed form solution with geometry approach. The simulation result obtained from forward kinematics and inverse kinematics is determining desired position by Denso robot manipulator. Forward kinematics produce the desired position by the end-effector. Inverse kinematics produce joint angle, where the inverse kinematics produce eight conditions obtained from closed form solution with geometry approach to reach the desired position by the end-effector.

  6. Kinematic relations in heavy-ion reactions

    International Nuclear Information System (INIS)

    Gippner, P.; Kalpakchieva, R.

    1988-01-01

    The present work gives a short overview of the non-relativistic kinematics of nuclear reactions derived on the basis of the conservation laws of energy and linear momentum. Section 2 contains kinematic relations valid for two-body reactions, sections 3 makes use of these relations to describe sequential fission as a special case of reactions with three particles in the exit channel. It is the aim of this work to comprise the kinematic formulae essential for planning of experiments, data analysis and critical examination of the obtained results. (author)

  7. Effects of thigh holster use on kinematics and kinetics of active duty police officers

    OpenAIRE

    Larsen, Louise B.; Tranberg, Roy; Ramstrand, Nerrolyn

    2016-01-01

    Background: Body armour, duty belts and belt mounted holsters are standard equipment used by the Swedish police and have been shown to affect performance of police specific tasks, to decrease mobility and to potentially influence back pain. This study aimed to investigate the effects on gait kinematics and kinetics associated with use of an alternate load carriage system incorporating a thigh holster. Methods: Kinematic, kinetic and temporospatial data were collected using three dimensional g...

  8. Effect of trapezius muscle strength on three-dimensional scapular kinematics

    OpenAIRE

    Turgut, Elif; Duzgun, Irem; Baltaci, Gul

    2016-01-01

    [Purpose] This study aimed to investigate the effect of trapezius muscle isometric strength on three-dimensional scapular kinematics in asymptomatic shoulders. [Subjects and Methods] Thirty asymptomatic subjects were included to the study. Isometric strengths of the upper, middle, and lower trapezius muscle were measured using a handheld dynamometer. Three-dimensional scapular kinematics was recorded by an electromagnetic tracking device during frontal and sagittal plane elevation. For each m...

  9. Robot Kinematics, using Dual Quaternions

    Directory of Open Access Journals (Sweden)

    Mahmoud Gouasmi

    2012-03-01

    Full Text Available From the point of view of classical mechanics, deriving the equations of motion for systems of coupled rigid bodies is regarded as a straightforward procedure: once a suitable set of generalized coordinates and reference frames have been chosen, what remains is to either apply Lagrange’s equations or Newton and Euler’s equations to obtain the differential equations of motion. As the complexity of multibody system increases, the need for more elegant formulation of the equation of motion becomes an issue of paramount importance. Our primary focus is on the kinematic analysis of rigid bodies and serial manipulators (robotic systems  using simultaneously, both homogeneous transformations (4x4 matrices and Dual Quaternions, for the sake of results comparisons (cost,complexity,storage capacity etc. . This paper has been done mainly for educational and peadagogical purposes, hoping that the scientific community will finally adopt and use Dual Quaternions at least when dealing with multibody systems and specially robotics.

  10. A Soft Parallel Kinematic Mechanism.

    Science.gov (United States)

    White, Edward L; Case, Jennifer C; Kramer-Bottiglio, Rebecca

    2018-02-01

    In this article, we describe a novel holonomic soft robotic structure based on a parallel kinematic mechanism. The design is based on the Stewart platform, which uses six sensors and actuators to achieve full six-degree-of-freedom motion. Our design is much less complex than a traditional platform, since it replaces the 12 spherical and universal joints found in a traditional Stewart platform with a single highly deformable elastomer body and flexible actuators. This reduces the total number of parts in the system and simplifies the assembly process. Actuation is achieved through coiled-shape memory alloy actuators. State observation and feedback is accomplished through the use of capacitive elastomer strain gauges. The main structural element is an elastomer joint that provides antagonistic force. We report the response of the actuators and sensors individually, then report the response of the complete assembly. We show that the completed robotic system is able to achieve full position control, and we discuss the limitations associated with using responsive material actuators. We believe that control demonstrated on a single body in this work could be extended to chains of such bodies to create complex soft robots.

  11. Kinematic analysis of a televised medial ankle sprain

    Directory of Open Access Journals (Sweden)

    Francesca E. Wade

    2018-04-01

    Full Text Available Ankle sprains are one of the most prevalent athletic injuries. Prior work has investigated lateral ankle sprains, but research on generally more severe medial sprains is lacking. This case report performs a kinematic analysis using novel motion analysis methods on a non-contact medial ankle sprain. Peak eversion (50° occurred 0.2 seconds following ground contact, maximum velocity of 426°/s, while peak dorsiflexion (64° occurred with a greater maximum velocity (573°/s. The combination of dorsiflexion at ground contact and rapid eversion is associated with a non-contact eversion sprain. This study provides a quantitative analysis of the eversion ankle sprain injury mechanism. Keywords: Athletic injury, Biomechanics, Ankle injury, Kinematics

  12. Stroller running: Energetic and kinematic changes across pushing methods.

    Science.gov (United States)

    Alcantara, Ryan S; Wall-Scheffler, Cara M

    2017-01-01

    Running with a stroller provides an opportunity for parents to exercise near their child and counteract health declines experienced during early parenthood. Understanding biomechanical and physiological changes that occur when stroller running is needed to evaluate its health impact, yet the effects of stroller running have not been clearly presented. Here, three commonly used stroller pushing methods were investigated to detect potential changes in energetic cost and lower-limb kinematics. Sixteen individuals (M/F: 10/6) ran at self-selected speeds for 800m under three stroller conditions (2-Hands, 1-Hand, and Push/Chase) and an independent running control. A significant decrease in speed (p = 0.001) and stride length (ppushing method had a significant effect on speed (p = 0.001) and stride length (ppushing technique influences stroller running speed and kinematics. These findings suggest specific fitness effects may be achieved through the implementation of different pushing methods.

  13. Surface growth kinematics via local curve evolution

    KAUST Repository

    Moulton, Derek E.; Goriely, Alain

    2012-01-01

    of increasing complexity are provided, and we demonstrate how biologically relevant structures such as logarithmic shells and horns emerge as analytical solutions of the kinematics equations with a small number of parameters that can be linked to the underlying

  14. Kinematic anharmonicity of internal rotation of molecules

    International Nuclear Information System (INIS)

    Bataev, V.A.; Pupyshev, V.I.; Godunov, I.A.

    2017-01-01

    The methods of analysis the strongly coupled vibrations are proposed for a number of molecules of aromatic and heterocyclic carbonyl (and some others) compounds. The qualitative principles are formulated for molecular systems with a significant kinematic anharmonicity.

  15. Improved kinect-based spatiotemporal and kinematic treadmill gait assessment.

    Science.gov (United States)

    Eltoukhy, Moataz; Oh, Jeonghoon; Kuenze, Christopher; Signorile, Joseph

    2017-01-01

    A cost-effective, clinician friendly gait assessment tool that can automatically track patients' anatomical landmarks can provide practitioners with important information that is useful in prescribing rehabilitative and preventive therapies. This study investigated the validity and reliability of the Microsoft Kinect v2 as a potential inexpensive gait analysis tool. Ten healthy subjects walked on a treadmill at 1.3 and 1.6m·s -1 , as spatiotemporal parameters and kinematics were extracted concurrently using the Kinect and three-dimensional motion analysis. Spatiotemporal measures included step length and width, step and stride times, vertical and mediolateral pelvis motion, and foot swing velocity. Kinematic outcomes included hip, knee, and ankle joint angles in the sagittal plane. The absolute agreement and relative consistency between the two systems were assessed using interclass correlations coefficients (ICC2,1), while reproducibility between systems was established using Lin's Concordance Correlation Coefficient (rc). Comparison of ensemble curves and associated 90% confidence intervals (CI90) of the hip, knee, and ankle joint angles were performed to investigate if the Kinect sensor could consistently and accurately assess lower extremity joint motion throughout the gait cycle. Results showed that the Kinect v2 sensor has the potential to be an effective clinical assessment tool for sagittal plane knee and hip joint kinematics, as well as some spatiotemporal temporal variables including pelvis displacement and step characteristics during the gait cycle. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Kinematics and resolution at future ep colliders

    International Nuclear Information System (INIS)

    Bluemlein, J.; Klein, M.

    1992-01-01

    Limitations due to resolution and kinematics are discussed of the (Q 2 , x) range accessible with electron-proton colliders after HERA. For the time after HERA one may think of two electron-proton colliders: an asymmetric energy machine and a rather symmetric one. Both colliders are compared here in order to study the influence of the different E l /E p ratios on the accessible kinematic range which is restricted due to angular coverage, finite detector resolution and calibration uncertainties

  17. Inverse kinematic control of LDUA and TWRMS

    International Nuclear Information System (INIS)

    Yih, T.C.; Burks, B.L.; Kwon, Dong-Soo

    1995-01-01

    A general inverse kinematic analysis is formulated particularly for the redundant Light Duty Utility Arm (LDUA) and Tank Waste Retrieval Manipulator System (TWRMS). The developed approach is applicable to the inverse kinematic simulation and control of LDUA, TWRMS, and other general robot manipulators. The 4 x 4 homogeneous Cylindrical coordinates-Bryant angles (C-B) notation is adopted to model LDUA, TWRMS, and any robot composed of R (revolute), P (prismatic), and/or S (spherical) joints

  18. DIDACTIC AUTOMATED STATION OF COMPLEX KINEMATICS

    Directory of Open Access Journals (Sweden)

    Mariusz Sosnowski

    2014-03-01

    Full Text Available The paper presents the design, control system and software that controls the automated station of complex kinematics. Control interface and software has been developed and manufactured in the West Pomeranian University of Technology in Szczecin in the Department of Automated Manufacturing Systems Engineering and Quality. Conducting classes designed to teach programming and design of structures and systems for monitoring the robot kinematic components with non-standard structures was the reason for installation of the control system and software.

  19. Kinematical coincidence method in transfer reactions

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, L.; Amorini, F. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Auditore, L. [INFN Gruppo Collegato di Messina and Dipartimento di Fisica, Università di Messina (Italy); Berceanu, I. [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Cardella, G., E-mail: cardella@ct.infn.it [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Chatterjiee, M.B. [Saha Institute for Nuclear Physics, Kolkata (India); De Filippo, E. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Francalanza, L.; Gianì, R. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); Grassi, L. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Rudjer Boskovic Institute, Zagreb (Croatia); Grzeszczuk, A. [Institut of Physics, University of Silesia, Katowice (Poland); La Guidara, E. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Lanzalone, G. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Facoltà di Ingegneria e Architettura, Università Kore, Enna (Italy); Lombardo, I. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Scienze Fisiche, Università Federico II and INFN Sezione di Napoli (Italy); Loria, D.; Minniti, T. [INFN Gruppo Collegato di Messina and Dipartimento di Fisica, Università di Messina (Italy); Pagano, E.V. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); and others

    2013-07-01

    A new method to extract high resolution angular distributions from kinematical coincidence measurements in binary reactions is presented. Kinematics is used to extract the center of mass angular distribution from the measured energy spectrum of light particles. Results obtained in the case of {sup 10}Be+p→{sup 9}Be+d reaction measured with the CHIMERA detector are shown. An angular resolution of few degrees in the center of mass is obtained. The range of applicability of the method is discussed.

  20. Chiral quark model with relativistic kinematics

    International Nuclear Information System (INIS)

    Garcilazo, H.; Valcarce, A.

    2003-01-01

    The nonstrange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the σ meson) leads to an overall good description of the spectrum

  1. Chiral quark model with relativistic kinematics

    OpenAIRE

    Garcilazo, H.; Valcarce, A.

    2003-01-01

    The non-strange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the $\\sigma$ meson) leads to an overall good description of the spectrum.

  2. Dynamic Control of Kinematically Redundant Robotic Manipulators

    Directory of Open Access Journals (Sweden)

    Erling Lunde

    1987-07-01

    Full Text Available Several methods for task space control of kinematically redundant manipulators have been proposed in the literature. Most of these methods are based on a kinematic analysis of the manipulator. In this paper we propose a control algorithm in which we are especially concerned with the manipulator dynamics. The algorithm is particularly well suited for the class of redundant manipulators consisting of a relatively small manipulator mounted on a larger positioning part.

  3. Heavy baryon spectroscopy with relativistic kinematics

    International Nuclear Information System (INIS)

    Valcarce, A.; Garcilazo, H.; Vijande, J.

    2014-01-01

    We present a comparative Faddeev study of heavy baryon spectroscopy with nonrelativistic and relativistic kinematics. We show results for different standard hyperfine interactions with both kinematics in an attempt to learn about the light quark dynamics. We highlight the properties of particular states accessible in nowadays laboratories that would help in discriminating between different dynamical models. The advance in the knowledge of light quark dynamics is a key tool for the understanding of the existence of exotic hadrons.

  4. Kinematic gait analyses in healthy Golden Retrievers

    OpenAIRE

    Silva, Gabriela C.A.; Cardoso, Mariana Trés; Gaiad, Thais P.; Brolio, Marina P.; Oliveira, Vanessa C.; Assis Neto, Antonio; Martins, Daniele S.; Ambrósio, Carlos E.

    2014-01-01

    Kinematic analysis relates to the relative movement between rigid bodies and finds application in gait analysis and other body movements, interpretation of their data when there is change, determines the choice of treatment to be instituted. The objective of this study was to standardize the march of Dog Golden Retriever Healthy to assist in the diagnosis and treatment of musculoskeletal disorders. We used a kinematic analysis system to analyse the gait of seven dogs Golden Retriever, female,...

  5. Kinematics analysis of a novel planar parallel manipulator with kinematic redundancy

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Haibo; Guo, Sheng [Beijing Jiaotong University, Beijing (China)

    2017-04-15

    In this paper, a novel planar parallel manipulator with kinematic redundancy is proposed. First, the Degrees of freedom (DOF) of the whole parallel manipulator and the Relative DOF (RDOF) between the moving platform and fixed base are studied. The results indicate that the proposed mechanism is kinematically redundant. Then, the kinematics, Jacobian matrices and workspace of this proposed parallel manipulator with kinematic redundancy are analyzed. Finally, the statics simulation of the proposed parallel manipulator is performed. The obtained stress and displacement distribution can be used to determine the easily destroyed place in the mechanism configurations.

  6. The role of reversed kinematics and double kinematic solutions in nuclear reactions studies

    International Nuclear Information System (INIS)

    Kaplan, M.; Parker, W.E.; Moses, D.J.; Lacey, R.; Alexander, J.M.

    1993-01-01

    The advantages of reversed kinematics in nuclear reactions studies are discussed, with particular emphasis on the origin of double solutions in the reaction kinematics. This possibility for double solutions does not exist in normal kinematics, and provides the basis for a new method of imposing important experimental constraints on the uniqueness of fitting complex observations. By gating on one or the other of the two solutions, light particle kinematics can be greatly influenced in coincidence measurements. The power of the method is illustrated with data for the reaction 1030 MeV 121 Sb+ 27 Al, where charged particle emissions arise from several different sources. (orig.)

  7. Kinematics analysis of a novel planar parallel manipulator with kinematic redundancy

    International Nuclear Information System (INIS)

    Qu, Haibo; Guo, Sheng

    2017-01-01

    In this paper, a novel planar parallel manipulator with kinematic redundancy is proposed. First, the Degrees of freedom (DOF) of the whole parallel manipulator and the Relative DOF (RDOF) between the moving platform and fixed base are studied. The results indicate that the proposed mechanism is kinematically redundant. Then, the kinematics, Jacobian matrices and workspace of this proposed parallel manipulator with kinematic redundancy are analyzed. Finally, the statics simulation of the proposed parallel manipulator is performed. The obtained stress and displacement distribution can be used to determine the easily destroyed place in the mechanism configurations

  8. Kinematics of electroweak single top quark production

    International Nuclear Information System (INIS)

    Lueck, Jan; Karlsruhe U., EKP

    2006-01-01

    In this thesis, the t-channel matching procedure of two single-top signal Monte Carlo samples is optimized. The s- and matched t-channel samples, generated by MadEvent, are validated by comparing to ZTOP next-to-leading-order calculations. We find good agreement for all kinematic distributions we investigate, except for softer light quark jets due to gluon radiation. Since this has only minor impact on the s-channel, the corresponding MadEvent sample performs its task as expected. For the t-channel, we can conclude that the applied matching procedure leads to a MadEvent sample that successfully describes the kinematic distributions and rates of the 2nd-b quark. However, small differences remain. The discrepancy in the p T -ordered 2nd-leading light jets is mainly due to the absence of initial state gluon splitting and initial and final state gluon radiation matrix elements in the MadEvent sample production. The subsequent PYTHIA showering of the partons is apparently inappropriate for modeling those contributions and not intended for this purpose. The proper way would be to produce all relevant NLO matrix elements and match them as proposed in reference [15]. At present, an NLO-MC-generator for single-top is in preparation [41]. Probably it will be available for future iterations of single-top analyses and will redundantize further matching procedures. We estimate the systematic uncertainty on the single-top acceptance due to the Monte Carlo modeling and find an uncertainty of about 1% on the t-channel acceptance. We obtain a negligible uncertainty well below 1% on the s-channel acceptance. These acceptance uncertainties are very well acceptable for the single-top analyses that are currently under way. A sensitivity study of the simultaneous cross section measurement of the s- and t-channel single-top production modes is conducted. For this purpose, only statistical uncertainties are included. For a future integrated luminosity of 1 fb -1 , we expect to obtain an s

  9. Exploring the impact of constraints in quantum optimal control through a kinematic formulation

    International Nuclear Information System (INIS)

    Donovan, Ashley; Beltrani, Vincent; Rabitz, Herschel

    2013-01-01

    Highlights: • This work lays a foundation for studying constraints in quantum control simulations. • The underlying quantum control landscape in the presence of constraints is explored. • Constrained controls can encounter suboptimal traps in the landscape. • The controls are kinematic stand-ins for dynamic time-dependent controls. • A method is developed to transfer between constrained kinematic and dynamic controls. - Abstract: The control of quantum dynamics with tailored laser fields is finding growing experimental success. In practice, experiments will be subject to constraints on the controls that may prevent full optimization of the objective. A framework is presented for systematically investigating the impact of constraints in quantum optimal control simulations using a two-stage process starting with simple time-independent kinematic controls, which act as stand-ins for the traditional dynamic controls. The objective is a state-to-state transition probability, and constraints are introduced by restricting the kinematic control variables during optimization. As a second stage, the means to map from kinematic to dynamic controls is presented, thus enabling a simplified overall procedure for exploring how limited resources affect the ability to optimize the objective. A demonstration of the impact of imposing several types of kinematic constraints is investigated, thereby offering insight into constrained quantum controls

  10. Kinematic measures for upper limb robot-assisted therapy following stroke and correlations with clinical outcome measures: A review.

    Science.gov (United States)

    Tran, Vi Do; Dario, Paolo; Mazzoleni, Stefano

    2018-03-01

    This review classifies the kinematic measures used to evaluate post-stroke motor impairment following upper limb robot-assisted rehabilitation and investigates their correlations with clinical outcome measures. An online literature search was carried out in PubMed, MEDLINE, Scopus and IEEE-Xplore databases. Kinematic parameters mentioned in the studies included were categorized into the International Classification of Functioning, Disability and Health (ICF) domains. The correlations between these parameters and the clinical scales were summarized. Forty-nine kinematic parameters were identified from 67 articles involving 1750 patients. The most frequently used parameters were: movement speed, movement accuracy, peak speed, number of speed peaks, and movement distance and duration. According to the ICF domains, 44 kinematic parameters were categorized into Body Functions and Structure, 5 into Activities and no parameters were categorized into Participation and Personal and Environmental Factors. Thirteen articles investigated the correlations between kinematic parameters and clinical outcome measures. Some kinematic measures showed a significant correlation coefficient with clinical scores, but most were weak or moderate. The proposed classification of kinematic measures into ICF domains and their correlations with clinical scales could contribute to identifying the most relevant ones for an integrated assessment of upper limb robot-assisted rehabilitation treatments following stroke. Increasing the assessment frequency by means of kinematic parameters could optimize clinical assessment procedures and enhance the effectiveness of rehabilitation treatments. Copyright © 2018 IPEM. Published by Elsevier Ltd. All rights reserved.

  11. A nonlinear dynamics of trunk kinematics during manual lifting tasks.

    Science.gov (United States)

    Khalaf, Tamer; Karwowski, Waldemar; Sapkota, Nabin

    2015-01-01

    Human responses at work may exhibit nonlinear properties where small changes in the initial task conditions can lead to large changes in system behavior. Therefore, it is important to study such nonlinearity to gain a better understanding of human performance under a variety of physical, perceptual, and cognitive tasks conditions. The main objective of this study was to investigate whether the human trunk kinematics data during a manual lifting task exhibits nonlinear behavior in terms of determinist chaos. Data related to kinematics of the trunk with respect to the pelvis were collected using Industrial Lumbar Motion Monitor (ILMM), and analyzed applying the nonlinear dynamical systems methodology. Nonlinear dynamics quantifiers of Lyapunov exponents and Kaplan-Yorke dimensions were calculated and analyzed under different task conditions. The study showed that human trunk kinematics during manual lifting exhibits chaotic behavior in terms of trunk sagittal angular displacement, velocity and acceleration. The findings support the importance of accounting for nonlinear dynamical properties of biomechanical responses to lifting tasks.

  12. Scapular kinematics and muscle activities during pushing tasks.

    Science.gov (United States)

    Huang, Chun-Kai; Siu, Ka-Chun; Lien, Hen-Yu; Lee, Yun-Ju; Lin, Yang-Hua

    2013-01-01

    Pushing tasks are functional activities of daily living. However, shoulder complaints exist among workers exposed to regular pushing conditions. It is crucial to investigate the control of shoulder girdles during pushing tasks. The objective of the study was to demonstrate scapular muscle activities and motions on the dominant side during pushing tasks and the relationship between scapular kinematics and muscle activities in different pushing conditions. Thirty healthy adults were recruited to push a four-wheel cart in six pushing conditions. The electromyographic signals of the upper trapezius (UT) and serratus anterior (SA) muscles were recorded. A video-based system was used for measuring the movement of the shoulder girdle and scapular kinematics. Differences in scapular kinematics and muscle activities due to the effects of handle heights and weights of the cart were analyzed using two-way ANOVA with repeated measures. The relationships between scapular kinematics and muscle activities were examined by Pearson's correlation coefficients. The changes in upper trapezius and serratus anterior muscle activities increased significantly with increased pushing weights in the one-step pushing phase. The UT/SA ratio on the dominant side decreases significantly with increased handle heights in the one-step pushing phase. The changes in upward rotation, lateral slide and elevation of the scapula decreased with increased pushing loads in the trunk-forward pushing phase. This study indicated that increased pushing loads result in decreased motions of upward rotation, lateral slide and elevation of the scapula; decreased handle heights result in relatively increased activities of the serratus anterior muscles during pushing tasks.

  13. Inverse kinematic-based robot control

    Science.gov (United States)

    Wolovich, W. A.; Flueckiger, K. F.

    1987-01-01

    A fundamental problem which must be resolved in virtually all non-trivial robotic operations is the well-known inverse kinematic question. More specifically, most of the tasks which robots are called upon to perform are specified in Cartesian (x,y,z) space, such as simple tracking along one or more straight line paths or following a specified surfacer with compliant force sensors and/or visual feedback. In all cases, control is actually implemented through coordinated motion of the various links which comprise the manipulator; i.e., in link space. As a consequence, the control computer of every sophisticated anthropomorphic robot must contain provisions for solving the inverse kinematic problem which, in the case of simple, non-redundant position control, involves the determination of the first three link angles, theta sub 1, theta sub 2, and theta sub 3, which produce a desired wrist origin position P sub xw, P sub yw, and P sub zw at the end of link 3 relative to some fixed base frame. Researchers outline a new inverse kinematic solution and demonstrate its potential via some recent computer simulations. They also compare it to current inverse kinematic methods and outline some of the remaining problems which will be addressed in order to render it fully operational. Also discussed are a number of practical consequences of this technique beyond its obvious use in solving the inverse kinematic question.

  14. Kinematically Optimal Robust Control of Redundant Manipulators

    Science.gov (United States)

    Galicki, M.

    2017-12-01

    This work deals with the problem of the robust optimal task space trajectory tracking subject to finite-time convergence. Kinematic and dynamic equations of a redundant manipulator are assumed to be uncertain. Moreover, globally unbounded disturbances are allowed to act on the manipulator when tracking the trajectory by the endeffector. Furthermore, the movement is to be accomplished in such a way as to minimize both the manipulator torques and their oscillations thus eliminating the potential robot vibrations. Based on suitably defined task space non-singular terminal sliding vector variable and the Lyapunov stability theory, we derive a class of chattering-free robust kinematically optimal controllers, based on the estimation of transpose Jacobian, which seem to be effective in counteracting both uncertain kinematics and dynamics, unbounded disturbances and (possible) kinematic and/or algorithmic singularities met on the robot trajectory. The numerical simulations carried out for a redundant manipulator of a SCARA type consisting of the three revolute kinematic pairs and operating in a two-dimensional task space, illustrate performance of the proposed controllers as well as comparisons with other well known control schemes.

  15. Analisys and Choice of the Exoskeleton’s Actuator Kinematic Structure

    Directory of Open Access Journals (Sweden)

    A. A. Vereikin

    2014-01-01

    Full Text Available The urgency of designing of robotic exoskeletons as one of the most prospective means of modern robotics is proved. A literature review concerning the design issues of anthropomorphic walking robots and exoskeletons is performed. Some problems, accompanying the designing process of exoskeleton actuator, are highlighted. Among them synthesis of its tree-like kinematic structure takes leading place. Its complication is explained by the specific human-machine interaction.The problem of exoskeleton actuator kinematic scheme synthesis is formulated and possible approaches to its solution are shown. The paper presents the synthesis results obtained using the software complex CATIA-based means of ergonomic design. It investigates the degrees of freedom of human-operator’s foot, shin, and thigh. And it identifies a number of shortcomings of this software complex associated with the ambiguity to solve the inverse kinematics problem, leading to a significant complication of kinematics synthesis.A model of human lower limb on which further studies of the exoskeleton actuator kinematic scheme, ensuring fulfillment of the human-operator standard movements (squats, kick their feet, bending body, walking, running stairs, etc., are based, is developed in SolidWorks software complex. The reasonability of the exoskeleton kinematic scheme synthesis in software package SolidWorks using anthropometric data from the software complex CATIA, is justified.The proposed method allows to analyze different kinematic schemes of actuator for the stage of conceptual design and to choose the best of them in accordance with established criterions. Thus, the developer receives the final version of the kinematic scheme before the detailed design of the actuator starts, thus significantly reducing its labor costs.

  16. Cervical kinematics in patients with vestibular pathology vs. patients with neck pain: A pilot study.

    Science.gov (United States)

    Williams, Grace; Sarig-Bahat, Hilla; Williams, Katrina; Tyrrell, Ryan; Treleaven, Julia

    2017-01-01

    Research has consistently shown cervical kinematic impairments in subjects with persistent neck pain (NP). It could be reasoned that those with vestibular pathology (VP) may also have altered kinematics since vestibular stimulation via head movement can cause dizziness and visual disturbances. However, this has not been examined to date. This pilot study investigated changes in cervical kinematics between asymptomatic control, NP and VP subjects using a Virtual Reality (VR) system. It was hypothesised that there would be altered kinematics in VP subjects, which might be associated with dizziness and visual symptoms. Pilot cross sectional observational study. Twenty control, 14 VP and 20 NP subjects. Not applicable. Measures included questionnaires (neck disability index, pain on movement, dizziness and pain intensity, visual disturbances) and cervical kinematics (range, peak and mean velocity, smoothness, symmetry, and accuracy of cervical motion) using a virtual reality system. Results revealed significantly decreased mean velocity and symmetry of motion in both planes in those with NP but no differences in accuracy or range of motion. No significant differences were seen between VP subjects and asymptomatic controls. However, correlation analysis showed some moderate correlations between dizziness to selected kinematics in both the NP and the VP groups. These results support that cervical kinematics are altered in NP patients, with velocity most affected. There is potential for VP subjects to also have altered kinematics, especially those who experience dizziness. More research is required.

  17. Investigation of the nuclear matter density distributions of the exotic {sup 12}Be,{sup 14}Be and {sup 8}B nuclei by elastic proton scattering in inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Ilieva, Stoyanka

    2008-07-01

    In the current experiment, the differential cross sections for proton elastic scattering on the isotopes {sup 7,9,10,11,12,14}Be and {sup 8}B were measured. As results from the experiment, the absolute differential cross sections d{sigma}/dt as a function of the four momentum transfer t were obtained. In this work the differential cross sections for elastic p-{sup 12}Be, p-{sup 14}Be and p-{sup 8}B scattering at low t (t{<=}0.05(GeV/c){sup 2}) are presented. The measured cross sections were analyzed within the Glauber multiple-scattering theory using different density parameterizations, and the nuclear matter density distributions and radii of the investigated isotopes were determined. The determined rms matter radius is 3.11{+-}0.04{+-}0.13 fm. In the case of the {sup 12}Be nucleus the results showed an extended matter distribution as well. For this nucleus a matter radius of 2.82{+-}0.03{+-}0.12 fm was determined. An interesting result is that the free {sup 12}Be nucleus behaves differently from the core of {sup 14}Be and is much more extended than it. Preliminary experimental results for the isotope {sup 8}B are also presented. An extended matter distribution was obtained (though much more compact as compared to the neutron halos). A proton halo structure was observed for the first time with the proton elastic scattering method. The deduced matter radius is 2.60{+-}0.02{+-}0.26 fm. Results from the feasibility studies of the EXL detector setup, performed at the present ESR storage ring, are presented. (orig.)

  18. Kinematic segmentation of accretive wedges based on scaled sandbox experiments and their application to nature

    Science.gov (United States)

    Lohrmann, J.; Kukowski, N.; Oncken, O.

    2003-04-01

    Recording the incremental displacement field of scaled analogue simulations provides detailed data on wedge kinematics and timing of internal deformation. This is a very efficient tool to develop kinematic concepts and test mechanical theories, e.g. the critical-taper theory. Such models could not be validated until now by the available geological and geophysical data, since there was no information about the incremental displacement field. Recent GPS measurements and seismological investigations at convergent margins provide well-constrained strain-rates and kinematics of short-termed processes. These data allow the kinematic models that are based on analogue simulations to be tested against field observations. We investigate convergent accretive sand wedges in scaled analogue simulations. We define three kinematic segments based on distinctive wedge taper, displacement field and timing of deformation (recorded at a slow sampling rate, which represents the geological scale). Only one of these segments is in a critical state of stress, whereas the other segments are either in a sub-critical or stable state of stress. Such a kinematic segmentation is not predicted for ideally homogeneous wedge-shaped bodies by the critical-taper theory, but can be explained by the formation of localised weak shear zones, which preferentially accommodate deformation. These weak zones are formed in granular analogue materials, and also in natural rocks, since these materials show a strain-softening phase prior to the achievement of stable mechanical conditions. Therefore we suggest that the kinematic segmentation of convergent sand wedges should also be observed in natural settings, such as accretionary wedges, foreland fold-and-thrust belts and even entire orogens. To validate this hypothesis we compare strain rates from GPS measurements and kinematics deduced from focal mechanisms with the respective data from sandbox experiments. We present a strategy to compare strain rates and

  19. Kinematics and Dynamics of Roller Chain Drives

    DEFF Research Database (Denmark)

    Fuglede, Niels

    There are two main subjects of this work: Kinematic and dynamic modeling and analysis of roller chain drives. In the kinematic analysis we contribute first with a complete treatment of the roller chain drive modeled as a four-bar mechanism. This includes a general, exact and approximate analysis...... which is useful for predicting the characteristic loading of the roller chain drive. As a completely novel contribution, a kinematic model and analysis is presented which includes both spans and sprockets in a simple chain drive system. A general procedure for determination of the total wrapping length...... is presented, which also allows for exact sprocket center positions for a chain with a given number of links. Results show that the total chain wrapping length varies periodically with the tooth frequency. These results are of practical importance to both the design, installation and operation of roller chain...

  20. Probabilistic approach to manipulator kinematics and dynamics

    International Nuclear Information System (INIS)

    Rao, S.S.; Bhatti, P.K.

    2001-01-01

    A high performance, high speed robotic arm must be able to manipulate objects with a high degree of accuracy and repeatability. As with any other physical system, there are a number of factors causing uncertainties in the behavior of a robotic manipulator. These factors include manufacturing and assembling tolerances, and errors in the joint actuators and controllers. In order to study the effect of these uncertainties on the robotic end-effector and to obtain a better insight into the manipulator behavior, the manipulator kinematics and dynamics are modeled using a probabilistic approach. Based on the probabilistic model, kinematic and dynamic performance criteria are defined to provide measures of the behavior of the robotic end-effector. Techniques are presented to compute the kinematic and dynamic reliabilities of the manipulator. The effects of tolerances associated with the various manipulator parameters on the reliabilities are studied. Numerical examples are presented to illustrate the procedures

  1. Tibial rotation kinematics subsequent to knee arthroplasty

    Science.gov (United States)

    Collins, Duane J.; Khatib, Yasser H.; Parker, David A.; Jenkin, Deanne E.; Molnar, Robert B.

    2015-01-01

    Background The use of computer assisted joint replacement has facilitated precise intraoperative measurement of knee kinematics. The changes in “screw home mechanism” (SHM) resulting from Total Knee Arthroplasty (TKA) with different prostheses and constraints has not yet been accurately described. Methods A pilot study was first completed. Intraoperative kinematic data was collected two groups of 15 patients receiving different prostheses. Results On average, patients lost 5.3° of ER (SD = 6.1°). There was no significant difference between the prostheses or different prosthetic constraints. Conclusions There significant loss of SHM after TKA. Further research is required to understand its impact on patient function. PMID:25829754

  2. Interactive inverse kinematics for human motion estimation

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol; Hauberg, Søren; Lapuyade, Jerome

    2009-01-01

    We present an application of a fast interactive inverse kinematics method as a dimensionality reduction for monocular human motion estimation. The inverse kinematics solver deals efficiently and robustly with box constraints and does not suffer from shaking artifacts. The presented motion...... to significantly speed up the particle filtering. It should be stressed that the observation part of the system has not been our focus, and as such is described only from a sense of completeness. With our approach it is possible to construct a robust and computationally efficient system for human motion estimation....

  3. Inverse Kinematics of a Serial Robot

    Directory of Open Access Journals (Sweden)

    Amici Cinzia

    2016-01-01

    Full Text Available This work describes a technique to treat the inverse kinematics of a serial manipulator. The inverse kinematics is obtained through the numerical inversion of the Jacobian matrix, that represents the equation of motion of the manipulator. The inversion is affected by numerical errors and, in different conditions, due to the numerical nature of the solver, it does not converge to a reasonable solution. Thus a soft computing approach is adopted to mix different traditional methods to obtain an increment of algorithmic convergence.

  4. Growth Kinematics of Opening-Mode Fractures

    Science.gov (United States)

    Eichhubl, P.; Alzayer, Y.; Laubach, S.; Fall, A.

    2014-12-01

    Fracture aperture is a primary control on flow in fractured reservoirs of low matrix permeability including unconventional oil and gas reservoirs and most geothermal systems. Guided by principles of linear elastic fracture mechanics, fracture aperture is generally assumed to be a linear function of fracture length and elastic material properties. Natural opening-mode fractures with significant preserved aperture are observed in core and outcrop indicative of fracture opening strain accommodated by permanent solution-precipitation creep. Fracture opening may thus be decoupled from length growth if the material effectively weakens after initial elastic fracture growth by either non-elastic deformation processes or changes in elastic properties. To investigate the kinematics of fracture length and aperture growth, we reconstructed the opening history of three opening-mode fractures that are bridged by crack-seal quartz cement in Travis Peak Sandstone of the SFOT-1 well, East Texas. Similar crack-seal cement bridges had been interpreted to form by repeated incremental fracture opening and subsequent precipitation of quartz cement. We imaged crack-seal cement textures for bridges sampled at varying distance from the tips using scanning electron microscope cathodoluminescence, and determined the number and thickness of crack-seal cement increments as a function of position along the fracture length and height. Observed trends in increment number and thickness are consistent with an initial stage of fast fracture propagation relative to aperture growth, followed by a stage of slow propagation and pronounced aperture growth. Consistent with fluid inclusion observations indicative of fracture opening and propagation occurring over 30-40 m.y., we interpret the second phase of pronounced aperture growth to result from fracture opening strain accommodated by solution-precipitation creep and concurrent slow, possibly subcritical, fracture propagation. Similar deformation

  5. Kinematic geometry of a line trajectory in spatial motion

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghefari, Reem A. [King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-Baky, Rashad A. [University of Assiut, Assiu (Egypt)

    2015-09-15

    This paper derives the equations of line-trajectory in spatial motion by means of the E. Study dual-line coordinates. A special emphasis goes to the second-order motion properties for deriving a new proof of the Disteli formulae. As an application concise explicit expressions of the inflection line congruence are directly obtained. Also, a new metric is developed and used to investigate the geometrical properties and kinematics of line trajectory as well as Disteli axis. Finally, a theoretical expressions of point trajectories with special values of velocity and acceleration, which can be considered as a form Euler-Savary equation, for spherical and planar motions are discussed.

  6. Cluster mislocation in kinematic Sunyaev-Zel'dovich effect extraction

    Science.gov (United States)

    Calafut, Victoria; Bean, Rachel; Yu, Byeonghee

    2017-12-01

    We investigate the impact of a variety of analysis assumptions that influence cluster identification and location on the kinematic Sunyaev-Zel'dovich (kSZ) pairwise momentum signal and covariance estimation. Photometric and spectroscopic galaxy tracers from SDSS, WISE, and DECaLs, spanning redshifts 0.05 surveys the statistical and photometric errors will shrink markedly. Our results demonstrate that uncertainties introduced through using galaxy proxies for cluster locations will need to be fully incorporated, and actively mitigated, for the kSZ to reach its full potential as a cosmological constraining tool for dark energy and neutrino physics.

  7. Circadian rhythms in handwriting kinematics and legibility

    NARCIS (Netherlands)

    Jasper, Isabelle; Gordijn, Marijke; Haeussler, Andreas; Hermsdoerfer, Joachim

    The aim of the present study was to analyze the circadian rhythmicity in handwriting kinematics and legibility and to compare the performance between Dutch and German writers. Two subject groups underwent a 40 h sleep deprivation protocol under Constant Routine conditions either in Groningen (10

  8. Assessment of multi class kinematic wave models

    NARCIS (Netherlands)

    Van Wageningen-Kessels, F.L.M.; Van Lint, J.W.C.; Vuik, C.; Hoogendoorn, S.P.

    2012-01-01

    In the last decade many multi class kinematic wave (MCKW) traffic ow models have been proposed. MCKW models introduce heterogeneity among vehicles and drivers. For example, they take into account differences in (maximum) velocities and driving style. Nevertheless, the models are macroscopic and the

  9. Coordinate transformations, orthographic projections, and robot kinematics

    International Nuclear Information System (INIS)

    Crochetiere, W.J.

    1984-01-01

    Humans do not consciously think of moving each of their joints while they move their hands from one place to another. Likewise, robot arms can be commanded to move about in cartesian space without the need to address the individual joints. To do this, the direct and inverse kinematic equations of any robot arm must be derived. The direct kinematic equations uniquely transform the joint positions into the position (and orientation) of the hand, whereas the inverse kinematic equations transform the position (and orientation) of the hand into joint positions. The derivation of the inverse kinematic equations for any particular robot is a difficult problem which may have more than one solution. In this paper, these equations are derived for a six degree of freedom robot arm. A combination of matrix operations to perform coordinate rotations, and trigonometry within the appropriate orthographic projects to perform coordinate translations is employed. This complementary approach yields a solution which is more easily obtained, and also more easily visualized. The resulting solution was programmed into a real-time computer as a part of a higher level software system to control the motion of the arm

  10. About the kinematics of spinning particles

    International Nuclear Information System (INIS)

    Salesi, G.; Recami, E.; Istituto Nazionale di Fisica Nucleare, Milan; Campinas State Univ., SP

    1995-06-01

    Inserting the correct Lorentz factor into the definition of the 4-velocity vμ for spinning particles entails new kinematical properties for v 2 . The well-know constraint (identically true for scalar particles, but entering also the Dirac theory, and assumed a priori in all spinning particle models) P μ v μ =m is here derived in a self-consistent way

  11. Action experience changes attention to kinematic cues

    Directory of Open Access Journals (Sweden)

    Courtney eFilippi

    2016-02-01

    Full Text Available The current study used remote corneal reflection eye-tracking to examine the relationship between motor experience and action anticipation in 13-month-old infants. To measure online anticipation of actions infants watched videos where the actor’s hand provided kinematic information (in its orientation about the type of object that the actor was going to reach for. The actor’s hand orientation either matched the orientation of a rod (congruent cue or did not match the orientation of the rod (incongruent cue. To examine relations between motor experience and action anticipation, we used a 2 (reach first vs. observe first x 2 (congruent kinematic cue vs. incongruent kinematic cue between-subjects design. We show that 13-month-old infants in the observe first condition spontaneously generate rapid online visual predictions to congruent hand orientation cues and do not visually anticipate when presented incongruent cues. We further demonstrate that the speed that these infants generate predictions to congruent motor cues is correlated with their own ability to pre-shape their hands. Finally, we demonstrate that following reaching experience, infants generate rapid predictions to both congruent and incongruent hand shape cues—suggesting that short-term experience changes attention to kinematics.

  12. Dynamic characteristics of mirrors' kinematic mount

    International Nuclear Information System (INIS)

    Wu Wenkai; Du Qiang; Li Jingze; Chen Gang; Chen Xiaojuan; Xu Yuanli

    2002-01-01

    Applying exact constrain design principles, kinematic mount for precision positioning large aperture mirrors is designed; theoretical method is introduced to analyze its dynamic characteristics and the result of the experiment for mirrors, stability; accordingly, the methods to improve design are put forward

  13. Compton's Kinematics and Einstein - Ehrenfest's radiation theory

    International Nuclear Information System (INIS)

    Barranco, A.V.; Franca, H.M.

    1988-09-01

    The Compton Kinematic relations are obtained from entirely classical arguments, that is, without the corpuscular concept of the photon. The calculations are nonrelativistic and result from Einstein and Ehrenfest's radiation theory modified in order to introduce the effects of the classical zero-point fileds characteristic of Stochastic Electrodynamics. (author) [pt

  14. The kinematic algebras from the scattering equations

    International Nuclear Information System (INIS)

    Monteiro, Ricardo; O’Connell, Donal

    2014-01-01

    We study kinematic algebras associated to the recently proposed scattering equations, which arise in the description of the scattering of massless particles. In particular, we describe the role that these algebras play in the BCJ duality between colour and kinematics in gauge theory, and its relation to gravity. We find that the scattering equations are a consistency condition for a self-dual-type vertex which is associated to each solution of those equations. We also identify an extension of the anti-self-dual vertex, such that the two vertices are not conjugate in general. Both vertices correspond to the structure constants of Lie algebras. We give a prescription for the use of the generators of these Lie algebras in trivalent graphs that leads to a natural set of BCJ numerators. In particular, we write BCJ numerators for each contribution to the amplitude associated to a solution of the scattering equations. This leads to a decomposition of the determinant of a certain kinematic matrix, which appears naturally in the amplitudes, in terms of trivalent graphs. We also present the kinematic analogues of colour traces, according to these algebras, and the associated decomposition of that determinant

  15. Kinematic structures in galactic disc simulations

    NARCIS (Netherlands)

    Roca-F� brega, S.; Romero-Gómez, M.; Figueras, F.; Antoja Castelltort, Teresa; Valenzuela, O.; Henney, W.J.; Torres-Peimbert, S.

    2011-01-01

    N-body and test particle simulations have been used to characterize the stellar streams in the galactic discs of Milky Way type galaxies. Tools such as the second and third order moments of the velocity ellipsoid and clustering methods -EM-WEKA and FoF- allow characterizing these kinematic

  16. Compound nucleus studies withy reverse kinematics

    International Nuclear Information System (INIS)

    Moretto, L.G.

    1985-06-01

    Reverse kinematics reactions are used to demonstrate the compound nucleus origin of intermediate mass particles at low energies and the extension of the same mechanism at higher energies. No evidence has appeared in our energy range for liquid-vapor equilibrium or cold fragmentation mechanisms. 11 refs., 12 figs

  17. The kinematics of machinery outlines of a theory of machines

    CERN Document Server

    Reuleaux, Franz

    2012-01-01

    A classic on the kinematics of machinery, this volume was written by the Father of Kinematics. Reuleaux writes with authority and precision, developing the subject from its fundamentals. 450 figures. 1876 edition.

  18. The relationship between foot posture and lower limb kinematics during walking: A systematic review.

    Science.gov (United States)

    Buldt, Andrew K; Murley, George S; Butterworth, Paul; Levinger, Pazit; Menz, Hylton B; Landorf, Karl B

    2013-07-01

    Variations in foot posture, such as pes planus (low-arched foot) or pes cavus (high-arched foot), are thought to be an intrinsic risk factor for injury due to altered motion of the lower extremity. Hence, the aim of this systematic review was to investigate the relationship between foot posture and lower limb kinematics during walking. A systematic database search of MEDLINE, CINAHL, SPORTDiscus, Embase and Inspec was undertaken in March 2012. Two independent reviewers applied predetermined inclusion criteria to selected articles for review and selected articles were assessed for quality. Articles were then grouped into two broad categories: (i) those comparing mean kinematic parameters between different foot postures, and (ii) those examining associations between foot posture and kinematics using correlation analysis. A final selection of 12 articles was reviewed. Meta-analysis was not conducted due to heterogeneity between studies. Selected articles primarily focused on comparing planus and normal foot postures. Five articles compared kinematic parameters between different foot postures - there was some evidence for increased motion in planus feet, but this was limited by small effect sizes. Seven articles investigated associations between foot posture and kinematics - there was evidence that increasing planus foot posture was positively associated with increased frontal plane motion of the rearfoot. The body of literature provides some evidence of a relationship between pes planus and increased lower limb motion during gait, however this was not conclusive due to heterogeneity between studies and small effect sizes. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. The Maiden Voyage of a Kinematics Robot

    Science.gov (United States)

    Greenwolfe, Matthew L.

    2015-04-01

    In a Montessori preschool classroom, students work independently on tasks that absorb their attention in part because the apparatus are carefully designed to make mistakes directly observable and limit exploration to one aspect or dimension. Control of error inheres in the apparatus itself, so that teacher intervention can be minimal.1 Inspired by this example, I created a robotic kinematics apparatus that also shapes the inquiry experience. Students program the robot by drawing kinematic graphs on a computer and then observe its motion. Exploration is at once limited to constant velocity and constant acceleration motion, yet open to complex multi-segment examples difficult to achieve in the lab in other ways. The robot precisely and reliably produces the motion described by the students' graphs, so that the apparatus itself provides immediate visual feedback about whether their understanding is correct as they are free to explore within the hard-coded limits. In particular, the kinematic robot enables hands-on study of multi-segment constant velocity situations, which lays a far stronger foundation for the study of accelerated motion. When correction is anonymous—just between one group of lab partners and their robot—students using the kinematic robot tend to flow right back to work because they view the correction as an integral part of the inquiry learning process. By contrast, when correction occurs by the teacher and/or in public (e.g., returning a graded assignment or pointing out student misconceptions during class), students all too often treat the event as the endpoint to inquiry. Furthermore, quantitative evidence shows a large gain from pre-test to post-test scores using the Test of Understanding Graphs in Kinematics (TUG-K).

  20. Validation and Structural Analysis of the Kinematics Concept Test

    Science.gov (United States)

    Lichtenberger, A.; Wagner, C.; Hofer, S. I.; Stem, E.; Vaterlaus, A.

    2017-01-01

    The kinematics concept test (KCT) is a multiple-choice test designed to evaluate students' conceptual understanding of kinematics at the high school level. The test comprises 49 multiple-choice items about velocity and acceleration, which are based on seven kinematic concepts and which make use of three different representations. In the first part…

  1. Using robotics in kinematics classes: exploring braking and stopping distances

    Science.gov (United States)

    Brockington, Guilherme; Schivani, Milton; Barscevicius, Cesar; Raquel, Talita; Pietrocola, Maurício

    2018-03-01

    Research in the field of physics teaching has revealed high school students’ difficulties in establishing relations between kinematic equations and real movements. Moreover, there are well-known and significant challenges in their comprehension of graphic language content. Thus, this article explores a didactic activity which utilized robotics in order to investigate significant aspects of kinematics, gathering data and performing analyses and descriptions via graphs and mathematical equations which were indispensable for the analysis of the phenomena in question. Traffic safety appears as a main theme, with particular emphasis on the distinction between braking and stopping distances in harsh conditions, as observed in the robot vehicle’s tires and track. This active-learning investigation allows students to identify significant differences between the average value of the initial empirical braking position and that of the vehicle’s programmed braking position, enabling them to more deeply comprehend the relations between mathematical and graphic representations of this real phenomenon and the phenomenon itself, thereby providing a sense of accuracy to this study.

  2. Phalangeal joints kinematics during ostrich (Struthio camelus locomotion

    Directory of Open Access Journals (Sweden)

    Rui Zhang

    2017-01-01

    Full Text Available The ostrich is a highly cursorial bipedal land animal with a permanently elevated metatarsophalangeal joint supported by only two toes. Although locomotor kinematics in walking and running ostriches have been examined, these studies have been largely limited to above the metatarsophalangeal joint. In this study, kinematic data of all major toe joints were collected from gaits with double support (slow walking to running during stance period in a semi-natural setup with two selected cooperative ostriches. Statistical analyses were conducted to investigate the effect of locomotor gait on toe joint kinematics. The MTP3 and MTP4 joints exhibit the largest range of motion whereas the first phalangeal joint of the 4th toe shows the largest motion variability. The interphalangeal joints of the 3rd and 4th toes present very similar motion patterns over stance phases of slow walking and running. However, the motion patterns of the MTP3 and MTP4 joints and the vertical displacement of the metatarsophalangeal joint are significantly different during running and slow walking. Because of the biomechanical requirements, osctriches are likely to select the inverted pendulum gait at low speeds and the bouncing gait at high speeds to improve movement performance and energy economy. Interestingly, the motions of the MTP3 and MTP4 joints are highly synchronized from slow to fast locomotion. This strongly suggests that the 3rd and 4th toes really work as an “integrated system” with the 3rd toe as the main load bearing element whilst the 4th toe as the complementary load sharing element with a primary role to ensure the lateral stability of the permanently elevated metatarsophalangeal joint.

  3. Expression of emotion in the kinematics of locomotion.

    Science.gov (United States)

    Barliya, Avi; Omlor, Lars; Giese, Martin A; Berthoz, Alain; Flash, Tamar

    2013-03-01

    Here, we examine how different emotions-happiness, fear, sadness and anger-affect the kinematics of locomotion. We focus on a compact representation of locomotion properties using the intersegmental law of coordination (Borghese et al. in J Physiol 494(3):863-879, 1996), which states that, during the gait cycle of human locomotion, the elevation angles of the thigh, shank and foot do not evolve independently of each other but form a planar pattern of co-variation. This phenomenon is highly robust and has been extensively studied. The orientation of the plane has been correlated with changes in the speed of locomotion and with reduction in energy expenditure as speed increases. An analytical model explaining the conditions underlying the emergence of this plane and predicting its orientation reveals that it suffices to examine the amplitudes of the elevation angles of the different segments along with the phase shifts between them (Barliya et al. in Exp Brain Res 193:371-385, 2009). We thus investigated the influence of different emotions on the parameters directly determining the orientation of the intersegmental plane and on the angular rotation profiles of the leg segments, examining both the effect of changes in walking speed and effects independent of speed. Subjects were professional actors and naïve subjects with no training in acting. As expected, emotions were found to strongly affect the kinematics of locomotion, particularly walking speed. The intersegmental coordination patterns revealed that emotional expression caused additional modifications to the locomotion patterns that could not be explained solely by a change in speed. For all emotions except sadness, the amplitude of thigh elevation angles changed from those in neutral locomotion. The intersegmental plane was also differently oriented, especially during anger. We suggest that, while speed is the dominant variable allowing discrimination between different emotional gaits, emotion can be

  4. A kinematic study on (unintentional imitation in bottlenose dolphins

    Directory of Open Access Journals (Sweden)

    Luisa eSartori

    2015-08-01

    Full Text Available The aim of the present study was to investigate the effect of observing other’s movements on subsequent performance in bottlenose dolphins. The imitative ability of non-human animals has intrigued a number of researchers. So far, however, studies in dolphins have been confined to intentional imitation concerned with the explicit request to imitate other agents. In the absence of instruction to imitate, do dolphins (unintentionally replicate other’s movement features? To test this, dolphins were filmed while reaching and touching a stimulus before and after observing another dolphin (i.e., model performing the same action. All videos were reviewed and segmented in order to extract the relevant movements. A marker was inserted post-hoc via software on the videos upon the anatomical landmark of interest (i.e. rostrum and was tracked throughout the time course of the movement sequence. The movement was analyzed using an in-house software developed to perform two-dimensional (2D post-hoc kinematic analysis. The results indicate that dolphins’ kinematics is sensitive to other’s movement features. Movements performed for the ‘visuomotor priming’ condition were characterized by a kinematic pattern similar to that performed by the observed dolphin (i.e., model. Addressing the issue of spontaneous imitation in bottlenose dolphins might allow ascertaining whether the potential or impulse to produce an imitative action is generated, not just when they intend to imitate, but whenever they watch another conspecific’s behavior. In closing, this will clarify whether motor representational capacity is a by-product of factors specific to humans or whether more general characteristics such as processes of associative learning prompted by high level of encephalization could help to explain the evolution of this ability.

  5. Analytic structure of the n=7 scattering amplitude in N=4 SYM theory in multi-Regge kinematics. Conformal Regge cut contribution

    International Nuclear Information System (INIS)

    Bartels, Jochen; Kormilitzin, Andrey; Oxford Univ.; Lipatov, Lev N.; Oxford Univ.; St. Petersburg State Univ.

    2014-11-01

    In this second part of our investigation of the analytic structure of the 2→5 scattering amplitude in the planar limit of N=4 SYM in multi-Regge kinematics we compute, in all kinematic regions, the Regge cut contributions in leading order. The results are infrared finite and conformally invariant.

  6. The role of functional foot orthoses on calcaneal and tibial kinematics : a clinical perspective using 3-dimensional motion analysis

    OpenAIRE

    Kelly, Joseph J

    2010-01-01

    peer-reviewed In-shoe orthoses are used in the treatment and prevention of lower limb injuries in particular patellofemoral pain associated with subtalar joint pronation. The aim of this thesis was to investigate the precise effects of in-shoe orthotic on the Calcaneus and Tibia. Two-dimension frontal plane kinematics may be used in the clinical setting to determine static and dynamic kinematics of the lower limb and foot. The findings of this thesis highlight several limitations of the...

  7. Kinematics of galactic planetary nebulae

    International Nuclear Information System (INIS)

    Kiosa, M.I.; Khromov, G.S.

    1979-01-01

    The classical method of determining the components of the solar motion relative to the centroid of the system of planetary nebulae with known radial velocities is investigated. It is shown that this method is insensitive to random errors in the radial velocities and that low accuracy in determining the coordinates of the solar apex and motion results from the insufficient number of planetaries with measured radial velocities. The planetary nebulae are found not to satisfy well the law of differential galactic rotation with circular orbits. This is attributed to the elongation of their galactic orbits. A method for obtaining the statistical parallax of planetary nebulae is considered, and the parallax calculated from the tau components of their proper motion is shown to be the most reliable

  8. Prediction of Equilibrium States of Kinematic and Thermal Fields in Homogeneous Turbulence Submitted To the Rotation

    International Nuclear Information System (INIS)

    Chebbi, Besma; Bouzaiane, Mounir; Lili, Taieb

    2009-01-01

    In this work, effects of rotation on the evolution of kinematic and thermal fields in homogeneous sheared turbulence are investigated using second order closure modeling. The Launder-Reece-Ro di models, the Speziale-Sarkar-Gatski model and the Shih-Lumley models are retained for pressure-strain correlation and pressure-temperature correlation. Whereas classic models are retained for time evolution equations of kinematic and thermal dissipation rates. The fourth order Runge-Kutta method is used to resolve three non linear differential systems obtained after modeling. The numerical integration is carried out separately for several values of the dimensionless rotation number R equal to 0, 0.25 and 0.5. The obtained results are compared to the recent results of Direct Numerical Simulations of G.Brethouwer. The results have confirmed the asymptotic equilibrium behaviors of kinematic and thermal dimensionless parameters. Furthermore they have shown that rotation affects not only kinematic field but also thermal field. The coupling between the Speziale-Sarkar-Gatski model and the Launder-Reece-Rodi model is of a big contribution on the prediction of kinematic and thermal fields

  9. Evaluation of handwriting kinematics and pressure for differential diagnosis of Parkinson's disease.

    Science.gov (United States)

    Drotár, Peter; Mekyska, Jiří; Rektorová, Irena; Masarová, Lucia; Smékal, Zdeněk; Faundez-Zanuy, Marcos

    2016-02-01

    We present the PaHaW Parkinson's disease handwriting database, consisting of handwriting samples from Parkinson's disease (PD) patients and healthy controls. Our goal is to show that kinematic features and pressure features in handwriting can be used for the differential diagnosis of PD. The database contains records from 37 PD patients and 38 healthy controls performing eight different handwriting tasks. The tasks include drawing an Archimedean spiral, repetitively writing orthographically simple syllables and words, and writing of a sentence. In addition to the conventional kinematic features related to the dynamics of handwriting, we investigated new pressure features based on the pressure exerted on the writing surface. To discriminate between PD patients and healthy subjects, three different classifiers were compared: K-nearest neighbors (K-NN), ensemble AdaBoost classifier, and support vector machines (SVM). For predicting PD based on kinematic and pressure features of handwriting, the best performing model was SVM with classification accuracy of Pacc=81.3% (sensitivity Psen=87.4% and specificity of Pspe=80.9%). When evaluated separately, pressure features proved to be relevant for PD diagnosis, yielding Pacc=82.5% compared to Pacc=75.4% using kinematic features. Experimental results showed that an analysis of kinematic and pressure features during handwriting can help assess subtle characteristics of handwriting and discriminate between PD patients and healthy controls. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Effects of Kinesio taping on scapular kinematics of overhead athletes following muscle fatigue.

    Science.gov (United States)

    Zanca, Gisele Garcia; Grüninger, Bruno; Mattiello, Stela Márcia

    2016-08-01

    Scapular kinematics alterations have been found following muscle fatigue. Considering the importance of the lower trapezius in coordinated scapular movement, this study aimed to investigate the effects of elastic taping (Kinesio taping, KT) for muscle facilitation on scapular kinematics of healthy overhead athletes following muscle fatigue. Twenty-eight athletes were evaluated in a crossover, single-blind, randomized design, in three sessions: control (no taping), KT (KT with tension) and sham (KT without tension). Scapular tridimensional kinematics and EMG of clavicular and acromial portions of upper trapezius, lower trapezius and serratus anterior were evaluated during arm elevation and lowering, before and after a fatigue protocol involving repetitive throwing. Median power frequency decline of serratus anterior was significantly lower in KT session compared to sham, possibly indicating lower muscle fatigue. However, the effects of muscle fatigue on scapular kinematics were not altered by taping conditions. Although significant changes were found in scapular kinematics following muscle fatigue, they were small and not considered relevant. It was concluded that healthy overhead athletes seem to present an adaptive mechanism that avoids the disruption of scapular movement pattern following muscle fatigue. Therefore, these athletes do not benefit from the use of KT to assist scapular movement under the conditions tested. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Surface growth kinematics via local curve evolution

    KAUST Repository

    Moulton, Derek E.

    2012-11-18

    A mathematical framework is developed to model the kinematics of surface growth for objects that can be generated by evolving a curve in space, such as seashells and horns. Growth is dictated by a growth velocity vector field defined at every point on a generating curve. A local orthonormal basis is attached to each point of the generating curve and the velocity field is given in terms of the local coordinate directions, leading to a fully local and elegant mathematical structure. Several examples of increasing complexity are provided, and we demonstrate how biologically relevant structures such as logarithmic shells and horns emerge as analytical solutions of the kinematics equations with a small number of parameters that can be linked to the underlying growth process. Direct access to cell tracks and local orientation enables for connections to be made to the underlying growth process. © 2012 Springer-Verlag Berlin Heidelberg.

  12. Kinematics of the symbiotic system R Aqr

    Science.gov (United States)

    Navarro, S.; Corral, L. J.; Steffen, W.

    2014-04-01

    We present the results of the kinematical analysis of the symbiotic system R Aqr. We obtained high dispersion spectra with the MES spectrograph at the 2.1 m telescope of San Pedro Mártir (MEZCAL). The used filter were Ha + [NII], (λc = 6575Å, Δλ = 90Å). We analyse the [NII] λλ6583 line. When the observations are compared with previous ones by Solf (1992) we detected an important change in the projected velocities of the observed knots, supporting the idea of a precessing jet. We are working also in a 3-D kinematic model for the object using the measured velocities and the state of the model is presented.

  13. A non-linear kinematic hardening function

    International Nuclear Information System (INIS)

    Ottosen, N.S.

    1977-05-01

    Based on the classical theory of plasticity, and accepting the von Mises criterion as the initial yield criterion, a non-linear kinematic hardening function applicable both to Melan-Prager's and to Ziegler's hardening rule is proposed. This non-linear hardening function is determined by means of the uniaxial stress-strain curve, and any such curve is applicable. The proposed hardening function considers the problem of general reversed loading, and a smooth change in the behaviour from one plastic state to another nearlying plastic state is obtained. A review of both the kinematic hardening theory and the corresponding non-linear hardening assumptions is given, and it is shown that material behaviour is identical whether Melan-Prager's or Ziegler's hardening rule is applied, provided that the von Mises yield criterion is adopted. (author)

  14. The kinematic advantage of electric cars

    Science.gov (United States)

    Meyn, Jan-Peter

    2015-11-01

    Acceleration of a common car with with a turbocharged diesel engine is compared to the same type with an electric motor in terms of kinematics. Starting from a state of rest, the electric car reaches a distant spot earlier than the diesel car, even though the latter has a better specification for engine power and average acceleration from 0 to 100 km h-1. A three phase model of acceleration as a function of time fits the data of the electric car accurately. The first phase is a quadratic growth of acceleration in time. It is shown that the tenfold higher coefficient for the first phase accounts for most of the kinematic advantage of the electric car.

  15. Directed Neutron Beams From Inverse Kinematic Reactions

    Science.gov (United States)

    Vanhoy, J. R.; Guardala, N. A.; Glass, G. A.

    2011-06-01

    Kinematic focusing of an emitted fairly mono-energetic neutron beam by the use of inverse-kinematic reactions, i.e. where the projectile mass is greater than the target atom's mass, can provide for the utilization of a significant fraction of the fast neutron yield and also provide for a safer radiation environment. We examine the merit of various neutron production reactions and consider the practicalities of producing the primary beam using the suitable accelerator technologies. Preliminary progress at the NSWC-Carderock Positive Ion Accelerator Facility is described. Possible important applications for this type of neutron-based system can be both advanced medical imaging techniques and active "stand-off" interrogation of contraband items.

  16. 6th International Workshop on Computational Kinematics

    CERN Document Server

    Gracia, Alba

    2014-01-01

    Computational kinematics is an enthralling area of science with a rich spectrum of problems at the junction of mechanics, robotics, computer science, mathematics, and computer graphics. The covered topics include design and optimization of cable-driven robots, analysis of parallel manipulators, motion planning, numerical methods for mechanism calibration and optimization, geometric approaches to mechanism analysis and design, synthesis of mechanisms, kinematical issues in biomechanics, construction of novel mechanical devices, as well as detection and treatment of singularities. The results should be of interest for practicing and research engineers as well as Ph.D. students from the fields of mechanical and electrical engineering, computer science, and computer graphics. Indexed in Conference Proceedings Citation Index- Science (CPCI-S).

  17. Plasma electron hole kinematics. I. Momentum conservation

    Energy Technology Data Exchange (ETDEWEB)

    Hutchinson, I. H.; Zhou, C. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2016-08-15

    We analyse the kinematic properties of a plasma electron hole: a non-linear self-sustained localized positive electric potential perturbation, trapping electrons, which behaves as a coherent entity. When a hole accelerates or grows in depth, ion and electron plasma momentum is changed both within the hole and outside, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.

  18. Kinematic and Electromyographic Activity Changes during Back Squat with Submaximal and Maximal Loading

    Science.gov (United States)

    Erdag, Deniz

    2017-01-01

    The aim of this study was to investigate the possible kinematic and muscular activity changes with maximal loading during squat maneuver. Fourteen healthy male individuals, who were experienced at performing squats, participated in this study. Each subject performed squats with 80%, 90%, and 100% of the previously established 1 repetition maximum (1RM). Electromyographic (EMG) activities were measured for the vastus lateralis, vastus medialis, rectus femoris, semitendinosus, biceps femoris, gluteus maximus, and erector spinae by using an 8-channel dual-mode portable EMG and physiological signal data acquisition system (Myomonitor IV, Delsys Inc., Boston, MA, USA). Kinematical data were analyzed by using saSuite 2D kinematical analysis program. Data were analyzed with repeated measures analysis of variance (p squat may not be necessary for focusing on knee extensor improvement and may increase the lumbar injury risk. PMID:28546738

  19. Analyzing Robotic Kinematics Via Computed Simulations

    Science.gov (United States)

    Carnahan, Timothy M.

    1992-01-01

    Computing system assists in evaluation of kinematics of conceptual robot. Displays positions and motions of robotic manipulator within work cell. Also displays interactions between robotic manipulator and other objects. Results of simulation displayed on graphical computer workstation. System includes both off-the-shelf software originally developed for automotive industry and specially developed software. Simulation system also used to design human-equivalent hand, to model optical train in infrared system, and to develop graphical interface for teleoperator simulation system.

  20. Kinematics of Hooke universal joint robot wrists

    Science.gov (United States)

    Mckinney, William S., Jr.

    1988-01-01

    The singularity problem associated with wrist mechanisms commonly found on industrial manipulators can be alleviated by redesigning the wrist so that it functions as a three-axis gimbal system. This paper discussess the kinematics of gimbal robot wrists made of one and two Hooke universal joints. Derivations of the resolved rate motion control equations for the single and double Hooke universal joint wrists are presented using the three-axis gimbal system as a theoretical wrist model.

  1. A new kinematical definition of orbital eccentricity

    Directory of Open Access Journals (Sweden)

    Ninković S.

    2009-01-01

    Full Text Available A new concept of orbital eccentricity is given. The dimensionless quantities proposed in the present paper to serve as orbital eccentricities have a kinematical nature. The purpose is to use them in describing the motion for the case of three-dimensional orbits. A comparison done for nearly planar orbits shows that the values of the eccentricities proposed here do not differ significantly from those corresponding to the eccentricities of geometric nature usually applied.

  2. Kinematics of Laying an Automated Weapon System

    Science.gov (United States)

    2017-07-19

    UNCLASSIFIED UNCLASSIFIED AD-E403 899 Technical Report ARWSE-TR-16024 KINEMATICS OF LAYING AN AUTOMATED WEAPON SYSTEM...information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and...maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of

  3. Kinematical Test Theories for Special Relativity

    Science.gov (United States)

    Lämmerzahl, Claus; Braxmaier, Claus; Dittus, Hansjörg; Müller, Holger; Peters, Achim; Schiller, Stephan

    A comparison of certain kinematical test theories for Special Relativity including the Robertson and Mansouri-Sext test theories is presented and the accuracy of the experimental results testing Special Relativity are expressed in terms of the parameters appearing in these test theories. The theoretical results are applied to the most precise experimental results obtained recently for the isotropy of light propagation and the constancy of the speed of light.

  4. Local galactic kinematics: an isothermal model

    International Nuclear Information System (INIS)

    Nunez, J.

    1983-01-01

    The kinematical parameters of galactic rotation in the solar neighborhood and the corrections to the precession have been calculated. For this purpose, an isothermal model for the solar neighborhood has been used together with the high order momenta of the local stellar velocity distribution and the Ogorodnikov-Milne model. Both have been calculated using some samples of the ''512 Distant FK4/FK4 Sup. Stars'' of Fricke (1977) and of Gliese's Gatalogue. (author)

  5. Circadian rhythms in handwriting kinematics and legibility.

    Science.gov (United States)

    Jasper, Isabelle; Gordijn, Marijke; Häussler, Andreas; Hermsdörfer, Joachim

    2011-08-01

    The aim of the present study was to analyze the circadian rhythmicity in handwriting kinematics and legibility and to compare the performance between Dutch and German writers. Two subject groups underwent a 40 h sleep deprivation protocol under Constant Routine conditions either in Groningen (10 Dutch subjects) or in Berlin (9 German subjects). Both groups wrote every 3h a test sentence of similar structure in their native language. Kinematic handwriting performance was assessed with a digitizing tablet and evaluated by writing speed, writing fluency, and script size. Writing speed (frequency of strokes and average velocity) revealed a clear circadian rhythm, with a parallel decline during night and a minimum around 3:00 h in the morning for both groups. Script size and movement fluency did not vary with time of day in neither group. Legibility of handwriting was evaluated by intra-individually ranking handwriting specimens of the 13 sessions by 10 German and 10 Dutch raters. Whereas legibility ratings of the German handwriting specimens deteriorated during night in parallel with slower writing speed, legibility of the Dutch handwriting deteriorated not until the next morning. In conclusion, the circadian rhythm of handwriting kinematics seems to be independent of script language at least among the two tested western countries. Moreover, handwriting legibility is also subject to a circadian rhythm which, however, seems to be influenced by variations in the assessment protocol. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Scapula Kinematics of Youth Baseball Players

    Directory of Open Access Journals (Sweden)

    Oliver Gretchen

    2015-12-01

    Full Text Available Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg, with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER and maximum humeral internal rotation (MIR during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly.

  7. Color-Kinematics Duality for QCD Amplitudes

    CERN Document Server

    Johansson, Henrik

    2016-01-01

    We show that color-kinematics duality is present in tree-level amplitudes of quantum chromodynamics with massive flavored quarks. Starting with the color structure of QCD, we work out a new color decomposition for n-point tree amplitudes in a reduced basis of primitive amplitudes. These primitives, with k quark-antiquark pairs and (n-2k) gluons, are taken in the (n-2)!/k! Melia basis, and are independent under the color-algebra Kleiss-Kuijf relations. This generalizes the color decomposition of Del Duca, Dixon, and Maltoni to an arbitrary number of quarks. The color coefficients in the new decomposition are given by compact expressions valid for arbitrary gauge group and representation. Considering the kinematic structure, we show through explicit calculations that color-kinematics duality holds for amplitudes with general configurations of gluons and massive quarks. The new (massive) amplitude relations that follow from the duality can be mapped to a well-defined subset of the familiar BCJ relations for gluo...

  8. The Flipped Classroom and College Physics Students' Motivation and Understanding of Kinematics Graphs

    Science.gov (United States)

    Cagande, Jeffrey Lloyd L.; Jugar, Richard R.

    2018-01-01

    Reversing the traditional classroom activities, in the flipped classroom model students view lectures at home and perform activities during class period inside the classroom. This study investigated the effect of a flipped classroom implementation on college physics students' motivation and understanding of kinematics graphs. A Solomon four-group…

  9. Lateralized effects of orthographical irregularity and auditory memory load on the kinematics of transciption typewriting

    NARCIS (Netherlands)

    Bloemsaat, J.G.; Galen, G.P. van; Meulenbroek, R.G.J.

    2003-01-01

    This study investigated the combined effects of orthographical irregularity and auditory memory load on the kinematics of finger movements in a transcription-typewriting task. Eight right-handed touch-typists were asked to type 80 strings of ten seven-letter words. In half the trials an irregularly

  10. Auditory Imagery Shapes Movement Timing and Kinematics: Evidence from a Musical Task

    Science.gov (United States)

    Keller, Peter E.; Dalla Bella, Simone; Koch, Iring

    2010-01-01

    The role of anticipatory auditory imagery in music-like sequential action was investigated by examining timing accuracy and kinematics using a motion capture system. Musicians responded to metronomic pacing signals by producing three unpaced taps on three vertically aligned keys at the given tempo. Taps triggered tones in two out of three blocked…

  11. The effect of tendon loading on in-vitro carpal kinematics of the wrist joint

    NARCIS (Netherlands)

    Foumani, M.; Blankevoort, L.; Stekelenburg, C.; Strackee, S. D.; Carelsen, B.; Jonges, R.; Streekstra, G. J.

    2010-01-01

    Measurements of in-vitro carpal kinematics of the wrist provide valuable biomechanical data. Tendon loading is often applied during cadaver experiments to simulate natural stabilizing joint compression in the wrist joint. The purpose of this study was to investigate the effect of tendon loading on

  12. Effect of external pulsation on kinematics of fluid particles in the field ...

    Indian Academy of Sciences (India)

    The effect of external pulsation on a pair of stationary Lamb–Oseen vortices of equal strength has been analyzed to investigate kinematic behavior of a fluid particle. The assumption of vortices being treated stationary or fixed vortex filaments is valid in a reference frame attached to the vortex system with axes along and ...

  13. Running accuracy analysis of a 3-RRR parallel kinematic machine considering the deformations of the links

    Science.gov (United States)

    Wang, Liping; Jiang, Yao; Li, Tiemin

    2014-09-01

    Parallel kinematic machines have drawn considerable attention and have been widely used in some special fields. However, high precision is still one of the challenges when they are used for advanced machine tools. One of the main reasons is that the kinematic chains of parallel kinematic machines are composed of elongated links that can easily suffer deformations, especially at high speeds and under heavy loads. A 3-RRR parallel kinematic machine is taken as a study object for investigating its accuracy with the consideration of the deformations of its links during the motion process. Based on the dynamic model constructed by the Newton-Euler method, all the inertia loads and constraint forces of the links are computed and their deformations are derived. Then the kinematic errors of the machine are derived with the consideration of the deformations of the links. Through further derivation, the accuracy of the machine is given in a simple explicit expression, which will be helpful to increase the calculating speed. The accuracy of this machine when following a selected circle path is simulated. The influences of magnitude of the maximum acceleration and external loads on the running accuracy of the machine are investigated. The results show that the external loads will deteriorate the accuracy of the machine tremendously when their direction coincides with the direction of the worst stiffness of the machine. The proposed method provides a solution for predicting the running accuracy of the parallel kinematic machines and can also be used in their design optimization as well as selection of suitable running parameters.

  14. Hydrodynamic interactions in metachronal paddling: effects of varying stroke kinematics

    Science.gov (United States)

    Samaee, Milad; Kasoju, Vishwa; Lai, Hong Kuan; Santhanakrishnan, Arvind

    2017-11-01

    Crustaceans such as shrimp and krill use a drag-based technique for propulsion, in which multiple pairs of limbs are paddled rhythmically from the tail to the head. Each limb is phase-shifted in time relative to its neighbor. Most studies of this type of metachronal swimming have focused on the jet formed in the animal's wake. However, synergistic hydrodynamic interactions between adjacent limbs in metachrony have received minimal attention. We used a dynamically scaled robotic model to experimentally investigate how variations in stroke kinematics impact inter-paddle hydrodynamic interactions and thrust generation. Physical models of limbs were fitted to the robot and paddled with two different motion profiles (MPs)-1) MP1: metachronal power stroke (PS) and metachronal recovery stroke (RS); and 2) MP2: metachronal PS and synchronous RS. Stroke frequency and amplitude were maintained constant across both MPs. Our results show that MP2 produced faster jets in the thrust-generating direction as compared to MP1. The necessity for a pause in MP2 after completion of PS by the paddles leading the motion, prior to executing the synchronous RS, aided in further downstream flow propagation. The effect of using asymmetric stroke kinematics on thrust generated will be discussed.

  15. Kinematics of self-initiated and reactive karate punches.

    Science.gov (United States)

    Martinez de Quel, Oscar; Bennett, Simon J

    2014-03-01

    This study investigated whether within-task expertise affects the reported asymmetry in execution time exhibited in reactive and self-initiated movements. Karate practitioners and no-karate practitioners were compared performing a reverse punch in reaction to an external stimulus or following the intention to produce a response (self-initiated). The task was completed following the presentation of a specific (i.e., life-size image of opponent) or general stimulus and in the presence of click trains or white noise. Kinematic analyses indicated reactive movement had shorter time to peak velocity and movement time, as well as greater accuracy than self-initiated movement. These differences were independent of participant skill level although peak velocity was higher in the karate practice group than in the no-karate practice group. Reaction time (RT) of skilled participants was facilitated by a specific stimulus. There was no effect on RT or kinematic variables of the different type of auditory cues. The results of this study indicate that asymmetry in execution time of reactive and self-initiated movement holds irrespective of within-task expertise and stimulus specificity. This could have implications for training of sports and/or relearning of tasks that require rapid and accurate movements to intercept/contact a target.

  16. Kinematic GPS survey as validation of LIDAR strips accuracy

    Directory of Open Access Journals (Sweden)

    C. Gordini

    2006-06-01

    Full Text Available As a result of the catastrophic hydrogeological events which occurred in May 1998 in Campania, in the south of Italy, the distinctive features of airborne laser scanning mounted on a helicopter were used to survey the landslides at Sarno and Quindici. In order to survey the entire zone of interest, approximately 21 km2, it was necessary to scan 12 laser strips. Many problems arose during the survey: difficulties in receiving the GPS signal, complex terrain features and unfavorable atmospheric conditions. These problems were investigated and it emerged that one of the most influential factors is the quality of GPS signals. By analysing the original GPS data, the traces obtained by fixing phase ambiguity with an On The Fly (OTF algorithm were isolated from those with smoothed differential GPS solution (DGPS. Processing and analysis of laser data showed that not all the overlapping laser strips were congruent with each other. Since an external survey to verify the laser data accuracy was necessary, it was decided to utilize the kinematic GPS technique. The laser strips were subsequently adjusted, using the kinematic GPS data as reference points. Bearing in mind that in mountainous areas like the one studied here it is not possible to obtain nominal precision and accuracy, a good result was nevertheless obtained with a Digital Terrain Model (DTM of all the zones of interest.

  17. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints

    Science.gov (United States)

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-01-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component. PMID:27043580

  18. Wave kinematics and response of slender offshore structures. Vol 4: Wave kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Riber, H.J.

    1999-08-01

    The kinematics of large surface waves has been measured by means of sonar's placed on the sea floor at the Tyra field. Measurements from the most severe storm are analysed and extreme wave velocity profiles are compared to Stoke wave velocity profiles. Statistical distributions of crest velocity and wave celerity are presented. The analysis shows how the deviation from the Stokes prediction varies with wave heights and steepness. Analyses of the directional wave field leads to the conclusion that the extreme waves are three-dimensional. It is shown that the peculiar kinematics of extreme waves is of great relevance to the design of jacket type structures. (au)

  19. Using the Microsoft Kinect™ to assess 3-D shoulder kinematics during computer use.

    Science.gov (United States)

    Xu, Xu; Robertson, Michelle; Chen, Karen B; Lin, Jia-Hua; McGorry, Raymond W

    2017-11-01

    Shoulder joint kinematics has been used as a representative indicator to investigate musculoskeletal symptoms among computer users for office ergonomics studies. The traditional measurement of shoulder kinematics normally requires a laboratory-based motion tracking system which limits the field studies. In the current study, a portable, low cost, and marker-less Microsoft Kinect™ sensor was examined for its feasibility on shoulder kinematics measurement during computer tasks. Eleven healthy participants performed a standardized computer task, and their shoulder kinematics data were measured by a Kinect sensor and a motion tracking system concurrently. The results indicated that placing the Kinect sensor in front of the participants would yielded a more accurate shoulder kinematics measurements then placing the Kinect sensor 15° or 30° to one side. The results also showed that the Kinect sensor had a better estimate on shoulder flexion/extension, compared with shoulder adduction/abduction and shoulder axial rotation. The RMSE of front-placed Kinect sensor on shoulder flexion/extension was less than 10° for both the right and the left shoulder. The measurement error of the front-placed Kinect sensor on the shoulder adduction/abduction was approximately 10° to 15°, and the magnitude of error is proportional to the magnitude of that joint angle. After the calibration, the RMSE on shoulder adduction/abduction were less than 10° based on an independent dataset of 5 additional participants. For shoulder axial rotation, the RMSE of front-placed Kinect sensor ranged between approximately 15° to 30°. The results of the study suggest that the Kinect sensor can provide some insight on shoulder kinematics for improving office ergonomics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Kinematic relationship between rotation of lumbar spine and hip joints during golf swing in professional golfers.

    Science.gov (United States)

    Mun, Frederick; Suh, Seung Woo; Park, Hyun-Joon; Choi, Ahnryul

    2015-05-14

    Understanding the kinematics of the lumbar spine and hip joints during a golf swing is a basic step for identifying swing-specific factors associated with low back pain. The objective of this study was to examine the kinematic relationship between rotational movement of the lumbar spine and hip joints during a golf swing. Fifteen professional golfers participated in this study with employment of six infrared cameras to record their golf swings. Anatomical reference system of the upper torso, pelvis and thigh segments, and the location of each hip and knee joint were defined by the protocols of the kinematic model of previous studies. Lumbar spine and hip joint rotational angle was calculated utilizing the Euler angle method. Cross-correlation and angle-angle plot was used to examine the degree of kinematic relationship between joints. A fairly strong coupling relationship was shown between the lumbar spine and hip rotational movements with an average correlation of 0.81. Leading hip contribution to overall rotation was markedly high in the early stage of the downswing, while the lumbar spine contributed greater towards the end of the downswing; however, the relative contributions of the trailing hip and lumbar spine were nearly equal during the entire downswing. Most of the professional golfers participated in this study used a similar coordination strategy when moving their hips and lumbar spine during golf swings. The rotation of hips was observed to be more efficient in producing the overall rotation during the downswing when compared to the backswing. These results provide quantitative information to better understand the lumbar spine and hip joint kinematic characteristics of professional golfers. This study will have great potential to be used as a normal control data for the comparison with kinematic information among golfers with low back pain and for further investigation of golf swing-specific factors associated with injury.

  1. Differences in foot kinematics between young and older adults during walking.

    Science.gov (United States)

    Arnold, John B; Mackintosh, Shylie; Jones, Sara; Thewlis, Dominic

    2014-02-01

    Our understanding of age-related changes to foot function during walking has mainly been based on plantar pressure measurements, with little information on differences in foot kinematics between young and older adults. The purpose of this study was to investigate the differences in foot kinematics between young and older adults during walking using a multi-segment foot model. Joint kinematics of the foot and ankle for 20 young (mean age 23.2 years, standard deviation (SD) 3.0) and 20 older adults (mean age 73.2 years, SD 5.1) were quantified during walking with a 12 camera Vicon motion analysis system using a five segment kinematic model. Differences in kinematics were compared between older adults and young adults (preferred and slow walking speeds) using Student's t-tests or if indicated, Mann-Whitney U tests. Effect sizes (Cohen's d) for the differences were also computed. The older adults had a less plantarflexed calcaneus at toe-off (-9.6° vs. -16.1°, d = 1.0, p = range of motion (ROM) of the midfoot (11.9° vs. 14.8°, d = 1.3, p = young adults. Walking speed did not influence these differences, as they remained present when groups walked at comparable speeds. The findings of this study indicate that independent of walking speed, older adults exhibit significant differences in foot kinematics compared to younger adults, characterised by less propulsion and reduced mobility of multiple foot segments. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. A Novel Algorithm for the Generation of Distinct Kinematic Chain

    Science.gov (United States)

    Medapati, Sreenivasa Reddy; Kuchibhotla, Mallikarjuna Rao; Annambhotla, Balaji Srinivasa Rao

    2016-07-01

    Generation of distinct kinematic chains is an important topic in the design of mechanisms for various industrial applications i.e., robotic manipulator, tractor, crane etc. Many researchers have intently focused on this area and explained various processes of generating distinct kinematic chains which are laborious and complex. It is desirable to enumerate the kinematic chains systematically to know the inherent characteristics of a chain related to its structure so that all the distinct chains can be analyzed in depth, prior to the selection of a chain for a purpose. This paper proposes a novel and simple method with set of rules defined to eliminate isomorphic kinematic chains generating distinct kinematic chains. Also, this method simplifies the process of generating distinct kinematic chains even at higher levels i.e., 10-link, 11-link with single and multiple degree of freedom.

  3. Kinematic control of robot with degenerate wrist

    Science.gov (United States)

    Barker, L. K.; Moore, M. C.

    1984-01-01

    Kinematic resolved rate equations allow an operator with visual feedback to dynamically control a robot hand. When the robot wrist is degenerate, the computed joint angle rates exceed operational limits, and unwanted hand movements can result. The generalized matrix inverse solution can also produce unwanted responses. A method is introduced to control the robot hand in the region of the degenerate robot wrist. The method uses a coordinated movement of the first and third joints of the robot wrist to locate the second wrist joint axis for movement of the robot hand in the commanded direction. The method does not entail infinite joint angle rates.

  4. JFKengine: A Jacobian and Forward Kinematics Generator

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, K.N.

    2003-02-13

    During robot path planning and control the equations that describe the robot motions are determined and solved. Historically these expressions were derived analytically off-line. For robots that must adapt to their environment or perform a wide range of tasks, a way is needed to rapidly re-derive these expressions to take into account the robot kinematic changes, such as when a tool is added to the end-effector. The JFKengine software was developed to automatically produce the expressions representing the manipulator arm motion, including the manipulator arm Jacobian and the forward kinematic expressions. Its programming interface can be used in conjunction with robot simulation software or with robot control software. Thus, it helps to automate the process of configuration changes for serial robot manipulators. If the manipulator undergoes a geometric change, such as tool acquisition, then JFKengine can be invoked again from the control or simulation software, passing it parameters for the new arm configuration. This report describes the automated processes that are implemented by JFKengine to derive the kinematic equations and the programming interface by which it is invoked. Then it discusses the tree data structure that was chosen to store the expressions, followed by several examples of portions of expressions as represented in the tree. The C++ classes and their methods that implement the expression differentiation and evaluation operations are described. The algorithms used to construct the Jacobian and forward kinematic equations using these basic building blocks are then illustrated. The activity described in this report is part of a larger project entitled ''Multi-Optimization Criteria-Based Robot Behavioral Adaptability and Motion Planning'' that focuses on the development of a methodology for the generalized resolution of robot motion equations with time-varying configurations, constraints, and task objective criteria. A specific

  5. Theory of gearing kinematics, geometry, and synthesis

    CERN Document Server

    Radzevich, Stephen P

    2012-01-01

    The first book of its kind, Theory of Gearing: Kinematics, Geometry, and Synthesis systematically develops a scientific theory of gearing that makes it possible to synthesize novel gears with the desired performance. Written by a leading gearing expert who holds more than 200 patents, it presents a modern methodology for gear design. The proposed theory is based on a key postulate: all the design parameters for an optimal gear pair for a particular application can be derived from (a) a given configuration of the rotation vectors of the driving and driven shafts and (b) the power transmitted by

  6. Kinematical program package for nuclear reaction

    International Nuclear Information System (INIS)

    Dai Nengxiong; Xie Ying

    1988-01-01

    A FORTRAN package is designed to provide users as many conveniences as possible. Besides adopting man-machine interaction mode and setting nuclide mass file, there are still some other features which are, for examples, the functions of offering the initial values for some transcendental equations and evaluating all the kinematic variables in nuclear reactions at low energies of the form of T (p,1)2, T (p,12)3 and T (p,12)34. All these make the users much easier to use the package

  7. Null-strut calculus. I. Kinematics

    International Nuclear Information System (INIS)

    Kheyfets, A.; LaFave, N.J.; Miller, W.A.

    1990-01-01

    This paper describes the kinematics of null-strut calculus---a 3+1 Regge calculus approach to general relativity. We show how to model the geometry of spacetime with simplicial spacelike three-geometries (TET's) linked to ''earlier'' and ''later'' momentumlike lattice surfaces (TET * ) entirely by light rays or ''null struts.'' These three-layered lattice spacetime geometries are defined and analyzed using combinatorial formulas for the structure of polytopes. The following paper in this series describes how these three-layered spacetime lattices are used to model spacetimes in full conformity with Einstein's theory of gravity

  8. Kinematic reversal schemes for the geomagnetic dipole.

    Science.gov (United States)

    Levy, E. H.

    1972-01-01

    Fluctuations in the distribution of cyclonic convective cells, in the earth's core, can reverse the sign of the geomagnetic field. Two kinematic reversal schemes are discussed. In the first scheme, a field maintained by cyclones concentrated at low latitude is reversed by a burst of cyclones at high latitude. Conversely, in the second scheme, a field maintained predominantly by cyclones in high latitudes is reversed by a fluctuation consisting of a burst of cyclonic convection at low latitude. The precise fluid motions which produce the geomagnetic field are not known. However, it appears that, whatever the details are, a fluctuation in the distribution of cyclonic cells over latitude can cause a geomagnetic reversal.

  9. Kinematics of the CSE in VY CMa

    Science.gov (United States)

    Choi, Yoon Kyung

    2009-07-01

    We report on astrometric results of H2O and SiO masers in the circumstellar envelopes of VY Canis Majoris (VY CMa) carried out with VERA for 2 years. Absolute positions and proper motions of 3 different frequencies of masers were measured with phase-referencing analyses. Using the positions and the 3-dimensional velocities of the masers, we considered the 3-dimensional structures and kinematics of the circumstellar envelopes around VY CMa. The H2O masers show bipolar outflow along the line of sight, and the SiO masers have both expanding and contracting motions with less than 5 km/s.

  10. Spectral gaps, inertial manifolds and kinematic dynamos

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, Manuel [Departamento de Analisis Matematico, Universidad de Valladolid, 47005 Valladolid (Spain)]. E-mail: mnjmhd@am.uva.es

    2005-10-17

    Inertial manifolds are desirable objects when ones wishes a dynamical process to behave asymptotically as a finite-dimensional ones. Recently [Physica D 194 (2004) 297] these manifolds are constructed for the kinematic dynamo problem with time-periodic velocity. It turns out, however, that the conditions imposed on the fluid velocity to guarantee the existence of inertial manifolds are too demanding, in the sense that they imply that all the solutions tend exponentially to zero. The inertial manifolds are meaningful because they represent different decay rates, but the classical dynamos where the magnetic field is maintained or grows are not covered by this approach, at least until more refined estimates are found.

  11. Shoulder and Scapular Kinematics during the Windmill Softball Pitch

    OpenAIRE

    Backus, Sherry I.; Kraszewski, Andrew; Kontaxis, Andreas; Gibbons, Mandi; Bido, Jennifer; Graziano, Jessica; Hafer, Jocelyn; Jones, Kristofer J.; Hillstrom, Howard; Fealy, Stephen

    2013-01-01

    Objectives: Pitch count has been studied extensively in the overhand throwing athlete. However, pitch count and fatigue have not been systematically evaluated in the female windmill (underhand) throwing athlete. Direct kinematic measurements of the glenohumeral and scapulo-thoracic joint have not to be correlated and determined. The purpose is to measure scapular kinematics for the high school female windmill softball pitcher and identify kinematic adaptions and changes in pitching performanc...

  12. Kinematics and Workspace of a 4-DOF Hybrid Palletizing Robot

    Directory of Open Access Journals (Sweden)

    Yong Tao

    2014-06-01

    Full Text Available We presented the kinematical analysis of a 4-DOF hybrid palletizing robot. The palletizing robot structure was proposed and the arm model of the robot was presented. The kinematical analysis of the end robotic manipulator was given. As a result, the position, velocity, and acceleration curves as well as the maximum workspace were demonstrated by simulation in Matlab. This study would be useful for the kinematical characteristics of the 4-DOF palletizing robot in space.

  13. Static and kinematic formulation of planar reciprocal assemblies

    DEFF Research Database (Denmark)

    Parigi, Dario; Sassone, Mario; Kirkegaard, Poul Henning

    2014-01-01

    Planar reciprocal frames are two dimensional structures formed by elements joined together according to the principle of structural reciprocity. In this paper a rigorous formulation of the static and kinematic problem is proposed and developed extending the theory of pin-jointed assemblies....... This formulation is used to evaluate the static and kinematic determinacy of reciprocal assemblies from the properties of their equilibrium and kinematic matrices...

  14. Influence of chronic back pain on kinematic reactions to unpredictable arm pulls.

    Science.gov (United States)

    Götze, Martin; Ernst, Michael; Koch, Markus; Blickhan, Reinhard

    2015-03-01

    There is evidence that muscle reflexes are delayed in patients with chronic low back pain in response to perturbations. It is still unrevealed whether these delays accompanied by an altered kinematic or compensated by adaption of other muscle parameters. The aim of this study was to investigate whether chronic low back pain patients show an altered kinematic reaction and if such data are reliable for the classification of chronic low back pain. In an experiment involving 30 females, sudden lateral perturbations were applied to the arm of a subject in an upright, standing position. Kinematics was used to distinguish between chronic low back pain patients and healthy controls. A calculated model of a stepwise discriminant function analysis correctly predicted 100% of patients and 80% of healthy controls. The estimation of the classification error revealed a constant rate for the classification of the healthy controls and a slightly decreased rate for the patients. Observed reflex delays and identified kinematic differences inside and outside the region of pain during impaired movement indicated that chronic low back pain patients have an altered motor control that is not restricted to the lumbo-pelvic region. This applied paradigm of external perturbations can be used to detect chronic low back pain patients and also persons without chronic low back pain but with an altered motor control. Further investigations are essential to reveal whether healthy persons with changes in motor function have an increased potential to develop chronic back pain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Rigid-body kinematics versus flapping kinematics of a flapping wing micro air vehicle

    NARCIS (Netherlands)

    Caetano, J.V.; Weehuizen, M.B.; De Visser, C.C.; De Croon, G.C.H.E.; Mulder, M.

    2015-01-01

    Several formulations have been proposed to model the dynamics of ornithopters, with inconclusive results regarding the need for complex kinematic formulations. Furthermore, the impact of assumptions made in the collected results was never assessed by comparing simulations with real flight data. In

  16. Kinematical and dynamical models for barred spiral galaxies

    International Nuclear Information System (INIS)

    Davoust, E.

    1983-01-01

    This is a review of published works on the kinematics and dynamics of stellar bars and barred spiral galaxies. The periodic orbits of stars are elongated along the bar and enhance it out to a certain distance from the center. The important role of the interstellar gas is pointed out by the models of gas clouds and flows: the trajectories are also along the bar, but shock waves arise in front of the bar and transient spiral structures appear at its ends. These models reproduce the observed velocity fields fairly well. The investigations of the stability of axisymmetric galactic disks show that they are very unstable with respect to bar shaped perturbations and might explain why two thirds of the known spiral galaxies are barred [fr

  17. Comparative kinematical analyses of Venus flytrap (Dionaea muscipula snap traps

    Directory of Open Access Journals (Sweden)

    Simon Poppinga

    2016-05-01

    Full Text Available Although the Venus flytrap (Dionaea muscipula can be considered as one of the most extensively investigated carnivorous plants, knowledge is still scarce about diversity of the snap-trap motion, the functionality of snap traps under varying environmental conditions, and their opening motion. By conducting simple snap-trap closure experiments in air and under water, we present striking evidence that adult Dionaea snaps similarly fast in aerial and submersed states and, hence, is potentially able to gain nutrients from fast aquatic prey during seasonal inundation. We reveal three snapping modes of adult traps, all incorporating snap buckling, and show that millimeter-sized, much slower seedling traps do not yet incorporate such elastic instabilities. Moreover, opening kinematics of young and adult Dionaea snap traps reveal that reverse snap buckling is not performed, corroborating the assumption that growth takes place on certain trap lobe regions. Our findings are discussed in an evolutionary, biomechanical, functional–morphological and biomimetic context.

  18. Mandibular kinematics after orthognathic surgical treatment a pilot study.

    Science.gov (United States)

    Sforza, Chiarella; Ugolini, Alessandro; Rocchetta, Davide; Galante, Domenico; Mapelli, Andrea; Giannì, Aldo Bruno

    2010-03-01

    We recorded three-dimensional mandibular movements, while the mouth was being opened and closed, using an optoelectronic motion analyser in 14 patients (5 skeletal Class II, 9 skeletal Class III) who were being assessed 7-49 months after orthognathic operations, and in 44 healthy subjects. All 14 patients had satisfactory healing on clinical examination, and function had been restored. Mandibular movement was divided into its rotational and translational components. On maximum mouth opening, the patients had significantly less total displacement of the mandibular interincisor point (p=0.05), and more mandibular movement that was explained by pure condylar rotation (p=0.006), than control subjects. There was no significant relation between maximum mouth opening and percentage rotation. While mandibular motion was well restored clinically by orthognathic surgery, the kinematics of the joint were modified. Larger studies and longitudinal investigations are necessary to appreciate the clinical relevance of the variations in condylar rotational and translational components.

  19. Comparison of Two- and Three-Dimensional Methods for Analysis of Trunk Kinematic Variables in the Golf Swing.

    Science.gov (United States)

    Smith, Aimée C; Roberts, Jonathan R; Wallace, Eric S; Kong, Pui; Forrester, Stephanie E

    2016-02-01

    Two-dimensional methods have been used to compute trunk kinematic variables (flexion/extension, lateral bend, axial rotation) and X-factor (difference in axial rotation between trunk and pelvis) during the golf swing. Recent X-factor studies advocated three-dimensional (3D) analysis due to the errors associated with two-dimensional (2D) methods, but this has not been investigated for all trunk kinematic variables. The purpose of this study was to compare trunk kinematic variables and X-factor calculated by 2D and 3D methods to examine how different approaches influenced their profiles during the swing. Trunk kinematic variables and X-factor were calculated for golfers from vectors projected onto the global laboratory planes and from 3D segment angles. Trunk kinematic variable profiles were similar in shape; however, there were statistically significant differences in trunk flexion (-6.5 ± 3.6°) at top of backswing and trunk right-side lateral bend (8.7 ± 2.9°) at impact. Differences between 2D and 3D X-factor (approximately 16°) could largely be explained by projection errors introduced to the 2D analysis through flexion and lateral bend of the trunk and pelvis segments. The results support the need to use a 3D method for kinematic data calculation to accurately analyze the golf swing.

  20. The Pleiades apex and its kinematical structure

    Science.gov (United States)

    Elsanhoury, W. H.; Postnikova, E. S.; Chupina, N. V.; Vereshchagin, S. V.; Sariya, Devesh P.; Yadav, R. K. S.; Jiang, Ing-Guey

    2018-03-01

    A study of cluster characteristics and internal kinematical structure of the middle-aged Pleiades open star cluster is presented. The individual star apexes and various cluster kinematical parameters including the velocity ellipsoid parameters are determined using both Hipparcos and Gaia data. Modern astrometric parameters were taken from the Gaia Data Release 1 (DR1) in combination with the Radial Velocity Experiment Fifth Data Release (DR5). The necessary set of parameters including parallaxes, proper motions and radial velocities are used for n=17 stars from Gaia DR1+RAVE DR5 and for n=19 stars from the Hipparcos catalog using SIMBAD data base. Single stars are used to improve accuracy by eliminating orbital movements. RAVE DR5 measurements were taken only for the stars with the radial velocity errors not exceeding 2 km/s. For the Pleiades stars taken from Gaia, we found mean heliocentric distance as 136.8 ± 6.4 pc, and the apex position is calculated as: A_{CP}=92°.52± 1°.72, D_{CP}=-42°.28± 2°.56 by the convergent point method and A0=95°.59± 2°.30 and D0=-50°.90± 2°.04 using AD-diagram method (n=17 in both cases). The results are compared with those obtained historically before the Gaia mission era.

  1. The Impact of the Support System’s Kinematic Structure on Selected Kinematic and Dynamic Quantities of an Experimental Crane

    Directory of Open Access Journals (Sweden)

    Trąbka Arkadiusz

    2014-12-01

    Full Text Available This paper presents a comparative analysis of two kinematic structures of the support system (with supports with bilateral and unilateral constraints, which were used in an experimental model of a crane. The computational model was developed by using the ADAMS software. The impact of the kinematic structure of the support system on selected kinematic and dynamic values that were recorded during the slewing motion was analysed. It was found, among other things, that an increased number of degrees of freedom of the support system leads to multiple distortions of time characteristics of kinematic and dynamic quantities.

  2. Foot kinematics in patients with two patterns of pathological plantar hyperkeratosis

    Directory of Open Access Journals (Sweden)

    Bowker Peter

    2011-02-01

    Full Text Available Abstract Background The Root paradigm of foot function continues to underpin the majority of clinical foot biomechanics practice and foot orthotic therapy. There are great number of assumptions in this popular paradigm, most of which have not been thoroughly tested. One component supposes that patterns of plantar pressure and associated hyperkeratosis lesions should be associated with distinct rearfoot, mid foot, first metatarsal and hallux kinematic patterns. Our aim was to investigate the extent to which this was true. Methods Twenty-seven subjects with planter pathological hyperkeratosis were recruited into one of two groups. Group 1 displayed pathological plantar hyperkeratosis only under metatarsal heads 2, 3 and 4 (n = 14. Group 2 displayed pathological plantar hyperkeratosis only under the 1st and 5th metatarsal heads (n = 13. Foot kinematics were measured using reflective markers on the leg, heel, midfoot, first metatarsal and hallux. Results The kinematic data failed to identify distinct differences between these two groups of subjects, however there were several subtle (generally Conclusions There was some evidence of small differences between planter pathological hyperkeratosis groups. Nevertheless, there was too much similarity between the kinematic data displayed in each group to classify them as distinct foot types as the current clinical paradigm proposes.

  3. Difference in kinematical behavior between two landing tasks in male volleyball athletes

    Directory of Open Access Journals (Sweden)

    Glauber Ribeiro Pereira

    2010-09-01

    Full Text Available Anterior cruciate ligament (ACL injuries are common in sports. Studies investigating injury mechanisms have demonstrated that most injuries arise from landing tasks. Despite the demonstration of differences between male and female kinematics, there are no studies showing how males behave during different landing tasks. The objective of this study was to compare the angular and temporal kinematics of the lower limbs between two different landing tasks. Double leg and single leg landings were recorded in the frontal and sagittal plane in 15 male volleyball athletes by videogrammetry. Reduced hip and knee flexion and increased knee valgus were observed in the single leg landing task compared to the double leg landing task. No significant difference in landing time was observed between the two tasks. In conclusion, the results support the premise that lower limb kinematics change according to the task performed. Further studies are necessary to explore the impact of these kinematic differences on knee loading and to relate them to ACL injury mechanisms in men.

  4. Deviating running kinematics and hamstring injury susceptibility in male soccer players: Cause or consequence?

    Science.gov (United States)

    Schuermans, Joke; Van Tiggelen, Damien; Palmans, Tanneke; Danneels, Lieven; Witvrouw, Erik

    2017-09-01

    Although the vast majority of hamstring injuries in male soccer are sustained during high speed running, the association between sprinting kinematics and hamstring injury vulnerability has never been investigated prospectively in a cohort at risk. This study aimed to objectify the importance of lower limb and trunk kinematics during full sprint in hamstring injury susceptibility. Cohort study; level of evidence, 2. At the end of the 2013 soccer season, three-dimensional kinematic data of the lower limb and trunk were collected during sprinting in a cohort consisting of 30 soccer players with a recent history of hamstring injury and 30 matched controls. Subsequently, a 1.5 season follow up was conducted for (re)injury registry. Ultimately, joint and segment motion patterns were submitted to retro- and prospective statistical curve analyses for injury risk prediction. Statistical analysis revealed that index injury occurrence was associated with higher levels of anterior pelvic tilting and thoracic side bending throughout the airborne (swing) phases of sprinting, whereas no kinematic differences during running were found when comparing players with a recent hamstring injury history with their matched controls. Deficient core stability, enabling excessive pelvis and trunk motion during swing, probably increases the primary injury risk. Although sprinting encompasses a relative risk of hamstring muscle failure in every athlete, running coordination demonstrated to be essential in hamstring injury prevention. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Transfer-induced fission in inverse kinematics: Impact on experimental and evaluated nuclear data bases

    Energy Technology Data Exchange (ETDEWEB)

    Farget, F.; Schmidt, K.H.; Clement, E.; Delaune, O.; Derkx, X.; Dijon, A.; Golabek, C.; Lemasson, A.; Roger, T.; Schmitt, C. [CEA/DSM-CNRS/IN2P3, GANIL, Caen (France); Caamano, M.; Ramos, D.; Benlliure, J.; Cortina, D.; Fernandez-Dominguez, B.; Paradela, C. [Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Rodriguez-Tajes, C. [CEA/DSM-CNRS/IN2P3, GANIL, Caen (France); Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Audouin, L. [Universite Paris-Sud 11, CNRS/IN2P3, Institut de Physique Nucleaire, Orsay (France); Casarejos, E. [Universidade de Vigo, Vigo (Spain); Dore, D.; Salsac, M.D. [Centre de Saclay, CEA, Irfu, Gif-sur-Yvette (France); Gaudefroy, L. [CEA DAM Ile-de-France, BP 12, Bruyeres-le-Chatel (France); Heinz, A. [Chalmers Tekniska Hoegskola, Fundamental Fysik, Goeteborg (Sweden); Jurado, B. [Universite Bordeaux, CENBG, UMR 5797 CNRS/IN2P3, Gradignan (France)

    2015-12-15

    Inverse kinematics is a new tool to study nuclear fission. Its main advantage is the possibility to measure with an unmatched resolution the atomic number of fission fragments, leading to new observables in the properties of fission-fragment distributions. In addition to the resolution improvement, the study of fission based on nuclear collisions in inverse kinematics beneficiates from a larger view with respect to the neutron-induced fission, as in a single experiment the number of fissioning systems and the excitation energy range are widden. With the use of spectrometers, mass and kinetic-energy distributions may now be investigated as a function of the proton and neutron number sharing. The production of fissioning nuclei in transfer reactions allows studying the isotopic yields of fission fragments as a function of the excitation energy. The higher excitation energy resulting in the fusion reaction leading to the compound nucleus {sup 250}Cf at an excitation energy of 45MeV is also presented. With the use of inverse kinematics, the charge polarisation of fragments at scission is now revealed with high precision, and it is shown that it cannot be neglected, even at higher excitation energies. In addition, the kinematical properties of the fragments inform on the deformation configuration at scission. (orig.)

  6. Outflow Kinematics Manifested by the Hα Line: Gas Outflows in Type 2 AGNs. IV

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Daeun; Woo, Jong-Hak; Bae, Hyun-Jin, E-mail: woo@astro.snu.ac.kr [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2017-08-20

    Energetic ionized gas outflows driven by active galactic nuclei (AGNs) have been studied as a key phenomenon related to AGN feedback. To probe the kinematics of the gas in the narrow-line region, [O iii] λ 5007 has been utilized in a number of studies showing nonvirial kinematic properties due to AGN outflows. In this paper, we statistically investigate whether the H α emission line is influenced by AGN-driven outflows by measuring the kinematic properties based on the H α line profile and comparing them with those of [O iii]. Using the spatially integrated spectra of ∼37,000 Type 2 AGNs at z < 0.3 selected from the Sloan Digital Sky Survey DR7, we find a nonlinear correlation between H α velocity dispersion and stellar velocity dispersion that reveals the presence of the nongravitational component, especially for AGNs with a wing component in H α . The large H α velocity dispersion and velocity shift of luminous AGNs are clear evidence of AGN outflow impacts on hydrogen gas, while relatively smaller kinematic properties compared to those of [O iii] imply that the observed outflow effect on the H α line is weaker than the case of [O iii].

  7. Application of Machine Learning in Postural Control Kinematics for the Diagnosis of Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Luís Costa

    2016-01-01

    Full Text Available The use of wearable devices to study gait and postural control is a growing field on neurodegenerative disorders such as Alzheimer’s disease (AD. In this paper, we investigate if machine-learning classifiers offer the discriminative power for the diagnosis of AD based on postural control kinematics. We compared Support Vector Machines (SVMs, Multiple Layer Perceptrons (MLPs, Radial Basis Function Neural Networks (RBNs, and Deep Belief Networks (DBNs on 72 participants (36 AD patients and 36 healthy subjects exposed to seven increasingly difficult postural tasks. The decisional space was composed of 18 kinematic variables (adjusted for age, education, height, and weight, with or without neuropsychological evaluation (Montreal cognitive assessment (MoCA score, top ranked in an error incremental analysis. Classification results were based on threefold cross validation of 50 independent and randomized runs sets: training (50%, test (40%, and validation (10%. Having a decisional space relying solely on postural kinematics, accuracy of AD diagnosis ranged from 71.7 to 86.1%. Adding the MoCA variable, the accuracy ranged between 91 and 96.6%. MLP classifier achieved top performance in both decisional spaces. Having comprehended the interdynamic interaction between postural stability and cognitive performance, our results endorse machine-learning models as a useful tool for computer-aided diagnosis of AD based on postural control kinematics.

  8. Electromiographic and kinematic characteristics of Kung Fu Yau-Man palm strike.

    Science.gov (United States)

    Neto, O P; Magini, Marcio

    2008-12-01

    A kinematic and electromyographic analysis of Kung Fu (KF) Yau-Man palm strikes without impact is presented. An empirical model applied to data obtained by a high-speed camera describes the kinematic characteristics of the movement. The electromyographic patterns of the biceps brachii, brachioradialis and triceps brachii muscles were studied during the strike in the time (root mean square) and frequency (wavelet transform) domains. Eight KF practitioners participated in the investigation. A wooden board was placed in front of the subjects, and they were asked to perform the strike imagining a target above the board. The results show that the Yau-Man KF palm strike has very similar kinematic characteristics to a simple moderate speed elbow extension movement. All practitioners positioned themselves in relation to the wooden board in a way to achieve their highest hand speeds in the instant their hands crossed the board. The analyses of the electromyography data shows a well developed muscle coordination of the practitioners in agreement with kinematic results. The results of this paper are important not only for improving the performance of practitioners but also to demonstrate the applicability of KF in the process of motor control development.

  9. Simultaneous and Continuous Estimation of Shoulder and Elbow Kinematics from Surface EMG Signals

    Directory of Open Access Journals (Sweden)

    Qin Zhang

    2017-05-01

    Full Text Available In this paper, we present a simultaneous and continuous kinematics estimation method for multiple DoFs across shoulder and elbow joint. Although simultaneous and continuous kinematics estimation from surface electromyography (EMG is a feasible way to achieve natural and intuitive human-machine interaction, few works investigated multi-DoF estimation across the significant joints of upper limb, shoulder and elbow joints. This paper evaluates the feasibility to estimate 4-DoF kinematics at shoulder and elbow during coordinated arm movements. Considering the potential applications of this method in exoskeleton, prosthetics and other arm rehabilitation techniques, the estimation performance is presented with different muscle activity decomposition and learning strategies. Principle component analysis (PCA and independent component analysis (ICA are respectively employed for EMG mode decomposition with artificial neural network (ANN for learning the electromechanical association. Four joint angles across shoulder and elbow are simultaneously and continuously estimated from EMG in four coordinated arm movements. By using ICA (PCA and single ANN, the average estimation accuracy 91.12% (90.23% is obtained in 70-s intra-cross validation and 87.00% (86.30% is obtained in 2-min inter-cross validation. This result suggests it is feasible and effective to use ICA (PCA with single ANN for multi-joint kinematics estimation in variant application conditions.

  10. Monitoring diver kinematics with dielectric elastomer sensors

    Science.gov (United States)

    Walker, Christopher R.; Anderson, Iain A.

    2017-04-01

    Diving, initially motivated for food purposes, is crucial to the oil and gas industry, search and rescue, and is even done recreationally by millions of people. There is a growing need however, to monitor the health and activity of divers. The Divers Alert Network has reported on average 90 fatalities per year since 1980. Furthermore an estimated 1000 divers require recompression treatment for dive-related injuries every year. One means of monitoring diver activity is to integrate strain sensors into a wetsuit. This would provide kinematic information on the diver potentially improving buoyancy control assessment, providing a platform for gesture communication, detecting panic attacks and monitoring diver fatigue. To explore diver kinematic monitoring we have coupled dielectric elastomer sensors to a wetsuit worn by the pilot of a human-powered wet submarine. This provided a unique platform to test the performance and accuracy of dielectric elastomer strain sensors in an underwater application. The aim of this study was to assess the ability of strain sensors to monitor the kinematics of a diver. This study was in collaboration with the University of Auckland's human-powered submarine team, Team Taniwha. The pilot, completely encapsulated in a hull, pedals to propel the submarine forward. Therefore this study focused on leg motion as that is the primary motion of the submarine pilot. Four carbon-filled silicone dielectric elastomer sensors were fabricated and coupled to the pilot's wetsuit. The first two sensors were attached over the knee joints, with the remaining two attached between the pelvis and thigh. The goal was to accurately measure leg joint angles thereby determining the position of each leg relative to the hip. A floating data acquisition unit monitored the sensors and transmitted data packets to a nearby computer for real-time processing. A GoPro Hero 4 silver edition was used to capture the experiments and provide a means of post-validation. The

  11. Neuromuscular training improves knee kinematics, in particular in valgus aligned adolescent team handball players of both sexes.

    NARCIS (Netherlands)

    Barendrecht, M.; Lezeman, H.C.; Duysens, J.E.J.; Smits-Engelsman, B.C.M.

    2011-01-01

    The purpose of this study was to investigate the effects of added neuromuscular training (NMT), as compared to just regular training (RT), on lower extremity kinematics and single leg stability in adolescent team handball players of both sexes and to investigate whether these effects are more

  12. Kinematic Earthquake Ground‐Motion Simulations on Listric Normal Faults

    KAUST Repository

    Passone, Luca

    2017-11-28

    Complex finite-faulting source processes have important consequences for near-source ground motions, but empirical ground-motion prediction equations still lack near-source data and hence cannot fully capture near-fault shaking effects. Using a simulation-based approach, we study the effects of specific source parameterizations on near-field ground motions where empirical data are limited. Here, we investigate the effects of fault listricity through near-field kinematic ground-motion simulations. Listric faults are defined as curved faults in which dip decreases with depth, resulting in a concave upward profile. The listric profiles used in this article are built by applying a specific shape function and varying the initial dip and the degree of listricity. Furthermore, we consider variable rupture speed and slip distribution to generate ensembles of kinematic source models. These ensembles are then used in a generalized 3D finite-difference method to compute synthetic seismograms; the corresponding shaking levels are then compared in terms of peak ground velocities (PGVs) to quantify the effects of breaking fault planarity. Our results show two general features: (1) as listricity increases, the PGVs decrease on the footwall and increase on the hanging wall, and (2) constructive interference of seismic waves emanated from the listric fault causes PGVs over two times higher than those observed for the planar fault. Our results are relevant for seismic hazard assessment for near-fault areas for which observations are scarce, such as in the listric Campotosto fault (Italy) located in an active seismic area under a dam.

  13. Similar complex kinematics within two massive, filamentary infrared dark clouds

    Science.gov (United States)

    Barnes, A. T.; Henshaw, J. D.; Caselli, P.; Jiménez-Serra, I.; Tan, J. C.; Fontani, F.; Pon, A.; Ragan, S.

    2018-04-01

    Infrared dark clouds (IRDCs) are thought to be potential hosts of the elusive early phases of high-mass star formation. Here, we conduct an in-depth kinematic analysis of one such IRDC, G034.43+00.24 (Cloud F), using high sensitivity and high spectral resolution IRAM-30m N2H+ (1-0) and C18O (1-0) observations. To disentangle the complex velocity structure within this cloud, we use Gaussian decomposition and hierarchical clustering algorithms. We find that four distinct coherent velocity components are present within Cloud F. The properties of these components are compared to those found in a similar IRDC, G035.39-00.33 (Cloud H). We find that the components in both clouds have high densities (inferred by their identification in N2H+), trans-to-supersonic non-thermal velocity dispersions with Mach numbers of ˜1.5-4, a separation in velocity of ˜3 km s-1, and a mean red-shift of ˜0.3 km s-1 between the N2H+ (dense gas) and C18O emission (envelope gas). The latter of these could suggest that these clouds share a common formation scenario. We investigate the kinematics of the larger-scale Cloud F structures, using lower-density-tracing 13CO(1-0) observations. A good correspondence is found between the components identified in the IRAM-30m observations and the most prominent component in the 13CO data. We find that the IRDC Cloud F is only a small part of a much larger structure, which appears to be an inter-arm filament of the Milky Way.

  14. Kinematic Earthquake Ground‐Motion Simulations on Listric Normal Faults

    KAUST Repository

    Passone, Luca; Mai, Paul Martin

    2017-01-01

    Complex finite-faulting source processes have important consequences for near-source ground motions, but empirical ground-motion prediction equations still lack near-source data and hence cannot fully capture near-fault shaking effects. Using a simulation-based approach, we study the effects of specific source parameterizations on near-field ground motions where empirical data are limited. Here, we investigate the effects of fault listricity through near-field kinematic ground-motion simulations. Listric faults are defined as curved faults in which dip decreases with depth, resulting in a concave upward profile. The listric profiles used in this article are built by applying a specific shape function and varying the initial dip and the degree of listricity. Furthermore, we consider variable rupture speed and slip distribution to generate ensembles of kinematic source models. These ensembles are then used in a generalized 3D finite-difference method to compute synthetic seismograms; the corresponding shaking levels are then compared in terms of peak ground velocities (PGVs) to quantify the effects of breaking fault planarity. Our results show two general features: (1) as listricity increases, the PGVs decrease on the footwall and increase on the hanging wall, and (2) constructive interference of seismic waves emanated from the listric fault causes PGVs over two times higher than those observed for the planar fault. Our results are relevant for seismic hazard assessment for near-fault areas for which observations are scarce, such as in the listric Campotosto fault (Italy) located in an active seismic area under a dam.

  15. Force generation of bio-inspired hover kinematics

    NARCIS (Netherlands)

    Vandenheede, R.B.R.; Bernal, L.P.; Morrison, C.L.; Humbert, S.

    2012-01-01

    This paper presents the results of an experimental study of the aerodynamics of an elliptical flap plate wing in pitch-plunge motion. Several wing motion kinematics are derived from the kinematics of the Agrius Convolvuli (hawk moth) in hover. The experiments are conducted at a Reynolds number of 4,

  16. A School Experiment in Kinematics: Shooting from a Ballistic Cart

    Science.gov (United States)

    Kranjc, T.; Razpet, N.

    2011-01-01

    Many physics textbooks start with kinematics. In the lab, students observe the motions, describe and make predictions, and get acquainted with basic kinematics quantities and their meaning. Then they can perform calculations and compare the results with experimental findings. In this paper we describe an experiment that is not often done, but is…

  17. Kinematic and neuromuscular relationships between lower extremity clinical movement assessments.

    Science.gov (United States)

    Mauntel, Timothy C; Cram, Tyler R; Frank, Barnett S; Begalle, Rebecca L; Norcross, Marc F; Blackburn, J Troy; Padua, Darin A

    2018-06-01

    Lower extremity injuries have immediate and long-term consequences. Lower extremity movement assessments can assist with identifying individuals at greater injury risk and guide injury prevention interventions. Movement assessments identify similar movement characteristics and evidence suggests large magnitude kinematic relationships exist between movement patterns observed across assessments; however, the magnitude of the relationships for electromyographic (EMG) measures across movement assessments remains largely unknown. This study examined relationships between lower extremity kinematic and EMG measures during jump landings and single leg squats. Lower extremity three-dimensional kinematic and EMG data were sampled from healthy adults (males = 20, females = 20) during the movement assessments. Pearson correlations examined the relationships of the kinematic and EMG measures and paired samples t-tests compared mean kinematic and EMG measures between the assessments. Overall, significant moderate correlations were observed for lower extremity kinematic (r avg  = 0.41, r range  = 0.10-0.61) and EMG (r avg  = 0.47, r range  = 0.32-0.80) measures across assessments. Kinematic and EMG measures were greater during the jump landings. Jump landings and single leg squats place different demands on the body and necessitate different kinematic and EMG patterns, such that these measures are not highly correlated between assessments. Clinicians should, therefore, use multiple assessments to identify aberrant movement and neuromuscular control patterns so that comprehensive interventions can be implemented.

  18. Kinematic and Dynamic Analysis of a Lower Limb Exoskeleton

    OpenAIRE

    Tawakal Hasnain Baluch; Adnan Masood; Javaid Iqbal; Umer Izhar; Umar Shahbaz Khan

    2012-01-01

    This paper will provide the kinematic and dynamic analysis of a lower limb exoskeleton. The forward and inverse kinematics of proposed exoskeleton is performed using Denevit and Hartenberg method. The torques required for the actuators will be calculated using Lagrangian formulation technique. This research can be used to design the control of the proposed exoskeleton.

  19. Kinematic synthesis of a new 3D printing solution

    Directory of Open Access Journals (Sweden)

    Giberti Hermes

    2016-01-01

    The object of this article is the kinematic synthesis of a 5Dofs robot, based on two PKM machines, for additive manufacturing in order to compliant with the requirements of this new technology. Robot kinematics have been optimized by genetic algorithm in order to cover the required workspace and the design of the robot and outline of the control system are also given.

  20. Kinematic analysis of competitive sprinting | Ansari | African Journal ...

    African Journals Online (AJOL)

    The results of the study showed that the kinematic variables i.e. knee angle, hip angle, ankle angle, shoulder rotation and extension had a significant influence on sprinting style. The results indicated that the kinematic variables of running style, knee angle at landing, hip flexion, ankle angle at landing, ankle angle at take-off, ...

  1. Plastic frames: Reduction of the kinematical inequality and optimization

    International Nuclear Information System (INIS)

    Brousse, P.

    1979-01-01

    It is well-known that the following inequality plays an essential part in the theory of perfectly plastic frames: for all kinematically admissible mechanisms and for bending moments associated with the hinge rotations by the flow rule, the plastic dissipation power is greater than or equal to the load power. This inequality will be termed as the kinematic inequality. It contains parameters generating the mechanisms. In simple cases, several ingenious authors obtained appreciable results excluding parameters. But, in more complicated cases, for instance when the given quantities are not numerical, the parameters remain in the kinematic inequality, thereby precluding exploitation of the kinematic approach. In the present work we overcome this dificulty: we reduce the kinematic inequality, i.e., we replace it by inequalities containing no variable parameter; we then state a process giving automatically such inequalities; finally, we treat a practical application. (orig.)

  2. Forward and inverse kinematics of double universal joint robot wrists

    Science.gov (United States)

    Williams, Robert L., II

    1991-01-01

    A robot wrist consisting of two universal joints can eliminate the wrist singularity problem found on many individual robots. Forward and inverse position and velocity kinematics are presented for such a wrist having three degrees of freedom. Denavit-Hartenberg parameters are derived to find the transforms required for the kinematic equations. The Omni-Wrist, a commercial double universal joint robot wrist, is studied in detail. There are four levels of kinematic parameters identified for this wrist; three forward and three inverse maps are presented for both position and velocity. These equations relate the hand coordinate frame to the wrist base frame. They are sufficient for control of the wrist standing alone. When the wrist is attached to a manipulator arm; the offset between the two universal joints complicates the solution of the overall kinematics problem. All wrist coordinate frame origins are not coincident, which prevents decoupling of position and orientation for manipulator inverse kinematics.

  3. Kinematic Analysis of Continuum Robot Consisted of Driven Flexible Rods

    Directory of Open Access Journals (Sweden)

    Yingzhong Tian

    2016-01-01

    Full Text Available This paper presents the kinematic analysis of a continuum bionic robot with three flexible actuation rods. Since the motion of the end-effector is actuated by the deformation of the rods, the robot structure is with high elasticity and good compliance and the kinematic analysis of the robot requires special treatment. We propose a kinematic model based on the geometry with constant curvature. The analysis consists of two independent mappings: a general mapping for the kinematics of all robots and a specific mapping for this kind of robots. Both of those mappings are developed for the single section and for the multisections. We aim at providing a guide for kinematic analysis of the similar manipulators through this paper.

  4. 21st Century Kinematics : The 2012 NSF Workshop

    CERN Document Server

    2013-01-01

    21st Century Kinematics focuses on algebraic problems in the analysis and synthesis of mechanisms and robots, compliant mechanisms, cable-driven systems and protein kinematics. The specialist contributors provide the background for a series of presentations at the 2012 NSF Workshop. The text shows how the analysis and design of innovative mechanical systems yield increasingly complex systems of polynomials, characteristic of those systems. In doing so, takes advantage of increasingly sophisticated computational tools developed for numerical algebraic geometry and demonstrates the now routine derivation of polynomial systems dwarfing the landmark problems of even the recent past. The 21st Century Kinematics workshop echoes the NSF-supported 1963 Yale Mechanisms Teachers Conference that taught a generation of university educators the fundamental principles of kinematic theory. As such these proceedings will be provide admirable supporting theory for a graduate course in modern kinematics and should be of consid...

  5. Expressions of manipulator kinematic equations via symbolic computation

    International Nuclear Information System (INIS)

    Sasaki, Shinobu

    1993-09-01

    While it is simple in principle to determine the position and orientation of the manipulator hand, its computational process has been regarded as extremely laborious since trigonometric functions must be calculated many times in operations of revolute or rotation. Due to development of a general class of kinematic algorithm based on iterative methods, however, we have come to a satisfactory settlement of this problem. In the present article, we consider to construct symbolic kinematic equations in an automatic fashion making use of the algorithm. To this end, recursive expressions are applied to a symbolic computation system REDUCE. As a concrete result, a complete kinematic model for a six-jointed arm having all kinematic attributes is provided. Together with work space analysis, the computer-aided generation of kinematic equations in symbolic form will serve to liberate us from their cumbersome derivations. (author)

  6. The Kinematic Learning Model using Video and Interfaces Analysis

    Science.gov (United States)

    Firdaus, T.; Setiawan, W.; Hamidah, I.

    2017-09-01

    An educator currently in demand to apply the learning to not be separated from the development of technology. Educators often experience difficulties when explaining kinematics material, this is because kinematics is one of the lessons that often relate the concept to real life. Kinematics is one of the courses of physics that explains the cause of motion of an object, Therefore it takes the thinking skills and analytical skills in understanding these symptoms. Technology is one that can bridge between conceptual relationship with real life. A framework of technology-based learning models has been developed using video and interfaces analysis on kinematics concept. By using this learning model, learners will be better able to understand the concept that is taught by the teacher. This learning model is able to improve the ability of creative thinking, analytical skills, and problem-solving skills on the concept of kinematics.

  7. 2nd Conference on Interdisciplinary Applications in Kinematics

    CERN Document Server

    Flores, Francisco

    2015-01-01

    This book collects a number of important contributions presented during the Second Conference on Interdisciplinary Applications of Kinematics (IAK 2013) held in Lima, Peru. The conference brought together scientists from several research fields, such as computational kinematics, multibody systems, industrial machines, robotics, biomechanics, mechatronics, computational chemistry, and vibration analysis, and embraced all key aspects of kinematics, namely, theoretical methods, modeling, optimization, experimental validation, industrial applications, and design. Kinematics is an exciting area of computational mechanics and plays  a central role in a great variety of fields and industrial applications nowadays. Apart from research in pure kinematics, the field deals with problems of practical relevance that need to be solved in an interdisciplinary manner in order for new technologies to develop. The results presented in this book should be of interest for practicing and research engineers as well as Ph.D. stud...

  8. Gas Kinematics in GRB Host Galaxies

    DEFF Research Database (Denmark)

    Arabsalmani, Maryam

    towards a relation between gas kinematics and mass. This also provides information on how the metallicities measured from absorption and emission methods differ from each other. Finally, in a direct study I show that gas velocity widths in both phases can be used as a proxy of stellar mass...... that their interstellar media imprint on the GRBs’ spectra. Hence they are invaluable tools to probe the star formation history of the Universe back to the earliest cosmic epochs. To this end, it is essential to achieve a comprehensive picture of the interplay between star formation and its fuel, neutral gas, in GRB...... simultaneously with a high velocity resolution. For the large GRB sample, I find the spatially averaged velocity to correlate with metallicity in both gas phases. This is an indicator of a mass-metallicity relation. Moreover, the velocity widths in the two gas phases correlate with each other which too points...

  9. Top quark kinematics and mass determination

    International Nuclear Information System (INIS)

    Williams, H.H.

    1994-10-01

    An analysis is presented of 10 W + ≥ 3 jet events, each with evidence for the presence of a b quark, that were recently observed by the CDF collaboration. Seven of these events include a fourth jet and can be explicitly reconstructed as t bar t production. The best estimate of the top quark mass is M t = 174 ± 10 -12 +13 GeV/c 2 . A study has also been performed to see if the kinematical properties of events with W + ≥ 3 jets gives evidence for top production. An excess of events with large jet energies, compared to that expected from direct production of W + ≥ 3 jets, is observed. A large fraction of these events also contain a b-quark and a fourth jet

  10. Differential Kinematics Of Contemporary Industrial Robots

    Science.gov (United States)

    Szkodny, T.

    2014-08-01

    The paper presents a simple method of avoiding singular configurations of contemporary industrial robot manipulators of such renowned companies as ABB, Fanuc, Mitsubishi, Adept, Kawasaki, COMAU and KUKA. To determine the singular configurations of these manipulators a global form of description of the end-effector kinematics was prepared, relative to the other links. On the basis of this description , the formula for the Jacobian was defined in the end-effector coordinates. Next, a closed form of the determinant of the Jacobian was derived. From the formula, singular configurations, where the determinant's value equals zero, were determined. Additionally, geometric interpretations of these configurations were given and they were illustrated. For the exemplary manipulator, small corrections of joint variables preventing the reduction of the Jacobian order were suggested. An analysis of positional errors, caused by these corrections, was presented

  11. Kinematics gait disorder in men with fibromyalgia.

    Science.gov (United States)

    Heredia-Jimenez, Jose M; Soto-Hermoso, Victor M

    2014-01-01

    The aim of this study was to assess the kinematics disorder of gait in men with fibromyalgia. We studied 12 male with fibromyalgia and 14 healthy men. Each participant of the study walked five trials along a 18.6-m walkway. Fibromyalgia patients completed a Spanish version of Fibromyalgia Impact Questionnaire. Significant differences between fibromyalgia and control groups were found in velocity, stride length, and cadence. Gait parameters of men affected by fibromyalgia were impaired when compared to those of healthy group due to bradykinesia. According to previous studies to assess gait variables in female patients, the male with fibromyalgia also showed lower values of velocity, cadence, and stride length than healthy group but not reported significant differences in swing, stance, single, or double support phase.

  12. Color-kinematic duality for form factors

    International Nuclear Information System (INIS)

    Boels, Rutger H.; Kniehl, Bernd A.; Tarasov, Oleg V.; Yang, Gang

    2012-12-01

    Recently a powerful duality between color and kinematics has been proposed for integrands of scattering amplitudes in quite general gauge theories. In this paper the duality proposal is extended to the more general class of gauge theory observables formed by form factors. After a discussion of the general setup the existence of the duality is verified in two and three loop examples in four dimensional maximally supersymmetric Yang-Mills theory which involve the stress energy tensor multiplet. In these cases the duality reproduces known results in a particularly transparent and uniform way. As a non-trivial application we obtain a very simple form of the integrand of the four-loop two-point (Sudakov) form factor which passes a large set of unitarity cut checks.

  13. Color-kinematic duality for form factors

    Energy Technology Data Exchange (ETDEWEB)

    Boels, Rutger H.; Kniehl, Bernd A.; Tarasov, Oleg V.; Yang, Gang [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2012-12-15

    Recently a powerful duality between color and kinematics has been proposed for integrands of scattering amplitudes in quite general gauge theories. In this paper the duality proposal is extended to the more general class of gauge theory observables formed by form factors. After a discussion of the general setup the existence of the duality is verified in two and three loop examples in four dimensional maximally supersymmetric Yang-Mills theory which involve the stress energy tensor multiplet. In these cases the duality reproduces known results in a particularly transparent and uniform way. As a non-trivial application we obtain a very simple form of the integrand of the four-loop two-point (Sudakov) form factor which passes a large set of unitarity cut checks.

  14. SPACEBAR: Kinematic design by computer graphics

    Science.gov (United States)

    Ricci, R. J.

    1975-01-01

    The interactive graphics computer program SPACEBAR, conceived to reduce the time and complexity associated with the development of kinematic mechanisms on the design board, was described. This program allows the direct design and analysis of mechanisms right at the terminal screen. All input variables, including linkage geometry, stiffness, and applied loading conditions, can be fed into or changed at the terminal and may be displayed in three dimensions. All mechanism configurations can be cycled through their range of travel and viewed in their various geometric positions. Output data includes geometric positioning in orthogonal coordinates of each node point in the mechanism, velocity and acceleration of the node points, and internal loads and displacements of the node points and linkages. All analysis calculations take at most a few seconds to complete. Output data can be viewed at the scope and also printed at the discretion of the user.

  15. Kinematic tests of exotic flat cosmological models

    International Nuclear Information System (INIS)

    Charlton, J.C.; Turner, M.S.; NASA/Fermilab Astrophysics Center, Batavia, IL)

    1987-01-01

    Theoretical prejudice and inflationary models of the very early universe strongly favor the flat, Einstein-de Sitter model of the universe. At present the observational data conflict with this prejudice. This conflict can be resolved by considering flat models of the universe which posses a smooth component of energy density. The kinematics of such models, where the smooth component is relativistic particles, a cosmological term, a network of light strings, or fast-moving, light strings is studied in detail. The observational tests which can be used to discriminate between these models are also discussed. These tests include the magnitude-redshift, lookback time-redshift, angular size-redshift, and comoving volume-redshift diagrams and the growth of density fluctuations. 58 references

  16. Kinematic tests of exotic flat cosmological models

    International Nuclear Information System (INIS)

    Charlton, J.C.; Turner, M.S.

    1986-05-01

    Theoretical prejudice and inflationary models of the very early Universe strongly favor the flat, Einstein-deSitter model of the Universe. At present the observational data conflict with this prejudice. This conflict can be resolved by considering flat models of the Universe which possess a smooth component by energy density. We study in detail the kinematics of such models, where the smooth component is relativistic particles, a cosmological term, a network of light strings, or fast-moving, light strings. We also discuss the observational tests which can be used to discriminate between these models. These tests include the magnitude-redshift, lookback time-redshift, angular size-redshift, and comoving volume-redshift diagrams and the growth of density fluctuations

  17. Kinematic tests of exotic flat cosmological models

    Energy Technology Data Exchange (ETDEWEB)

    Charlton, J.C.; Turner, M.S.

    1986-05-01

    Theoretical prejudice and inflationary models of the very early Universe strongly favor the flat, Einstein-deSitter model of the Universe. At present the observational data conflict with this prejudice. This conflict can be resolved by considering flat models of the Universe which possess a smooth component by energy density. We study in detail the kinematics of such models, where the smooth component is relativistic particles, a cosmological term, a network of light strings, or fast-moving, light strings. We also discuss the observational tests which can be used to discriminate between these models. These tests include the magnitude-redshift, lookback time-redshift, angular size-redshift, and comoving volume-redshift diagrams and the growth of density fluctuations.

  18. Assessment of representational competence in kinematics

    Directory of Open Access Journals (Sweden)

    P. Klein

    2017-06-01

    Full Text Available A two-tier instrument for representational competence in the field of kinematics (KiRC is presented, designed for a standard (1st year calculus-based introductory mechanics course. It comprises 11 multiple choice (MC and 7 multiple true-false (MTF questions involving multiple representational formats, such as graphs, pictures, and formal (mathematical expressions (1st tier. Furthermore, students express their answer confidence for selected items, providing additional information (2nd tier. Measurement characteristics of KiRC were assessed in a validation sample (pre- and post-test, N=83 and N=46, respectively, including usefulness for measuring learning gain. Validity is checked by interviews and by benchmarking KiRC against related measures. Values for item difficulty, discrimination, and consistency are in the desired ranges; in particular, a good reliability was obtained (KR20=0.86. Confidence intervals were computed and a replication study yielded values within the latter. For practical and research purposes, KiRC as a diagnostic tool goes beyond related extant instruments both for the representational formats (e.g., mathematical expressions and for the scope of content covered (e.g., choice of coordinate systems. Together with the satisfactory psychometric properties it appears a versatile and reliable tool for assessing students’ representational competency in kinematics (and of its potential change. Confidence judgments add further information to the diagnostic potential of the test, in particular for representational misconceptions. Moreover, we present an analytic result for the question—arising from guessing correction or educational considerations—of how the total effect size (Cohen’s d varies upon combination of two test components with known individual effect sizes, and then discuss the results in the case of KiRC (MC and MTF combination. The introduced method of test combination analysis can be applied to any test

  19. Assessment of representational competence in kinematics

    Science.gov (United States)

    Klein, P.; Müller, A.; Kuhn, J.

    2017-06-01

    A two-tier instrument for representational competence in the field of kinematics (KiRC) is presented, designed for a standard (1st year) calculus-based introductory mechanics course. It comprises 11 multiple choice (MC) and 7 multiple true-false (MTF) questions involving multiple representational formats, such as graphs, pictures, and formal (mathematical) expressions (1st tier). Furthermore, students express their answer confidence for selected items, providing additional information (2nd tier). Measurement characteristics of KiRC were assessed in a validation sample (pre- and post-test, N =83 and N =46 , respectively), including usefulness for measuring learning gain. Validity is checked by interviews and by benchmarking KiRC against related measures. Values for item difficulty, discrimination, and consistency are in the desired ranges; in particular, a good reliability was obtained (KR 20 =0.86 ). Confidence intervals were computed and a replication study yielded values within the latter. For practical and research purposes, KiRC as a diagnostic tool goes beyond related extant instruments both for the representational formats (e.g., mathematical expressions) and for the scope of content covered (e.g., choice of coordinate systems). Together with the satisfactory psychometric properties it appears a versatile and reliable tool for assessing students' representational competency in kinematics (and of its potential change). Confidence judgments add further information to the diagnostic potential of the test, in particular for representational misconceptions. Moreover, we present an analytic result for the question—arising from guessing correction or educational considerations—of how the total effect size (Cohen's d ) varies upon combination of two test components with known individual effect sizes, and then discuss the results in the case of KiRC (MC and MTF combination). The introduced method of test combination analysis can be applied to any test comprising

  20. Synthetic tsunami waveform catalogs with kinematic constraints

    Science.gov (United States)

    Baptista, Maria Ana; Miranda, Jorge Miguel; Matias, Luis; Omira, Rachid

    2017-07-01

    In this study we present a comprehensive methodology to produce a synthetic tsunami waveform catalogue in the northeast Atlantic, east of the Azores islands. The method uses a synthetic earthquake catalogue compatible with plate kinematic constraints of the area. We use it to assess the tsunami hazard from the transcurrent boundary located between Iberia and the Azores, whose western part is known as the Gloria Fault. This study focuses only on earthquake-generated tsunamis. Moreover, we assume that the time and space distribution of the seismic events is known. To do this, we compute a synthetic earthquake catalogue including all fault parameters needed to characterize the seafloor deformation covering the time span of 20 000 years, which we consider long enough to ensure the representability of earthquake generation on this segment of the plate boundary. The computed time and space rupture distributions are made compatible with global kinematic plate models. We use the tsunami empirical Green's functions to efficiently compute the synthetic tsunami waveforms for the dataset of coastal locations, thus providing the basis for tsunami impact characterization. We present the results in the form of offshore wave heights for all coastal points in the dataset. Our results focus on the northeast Atlantic basin, showing that earthquake-induced tsunamis in the transcurrent segment of the Azores-Gibraltar plate boundary pose a minor threat to coastal areas north of Portugal and beyond the Strait of Gibraltar. However, in Morocco, the Azores, and the Madeira islands, we can expect wave heights between 0.6 and 0.8 m, leading to precautionary evacuation of coastal areas. The advantages of the method are its easy application to other regions and the low computation effort needed.

  1. Training of goal directed arm movements with motion interactive video games in children with cerebral palsy - a kinematic evaluation.

    Science.gov (United States)

    Sandlund, Marlene; Domellöf, Erik; Grip, Helena; Rönnqvist, Louise; Häger, Charlotte K

    2014-10-01

    The main aim of this study was to evaluate the quality of goal-directed arm movements in 15 children with cerebral palsy (CP) following four weeks of home-based training with motion interactive video games. A further aim was to investigate the applicability and characteristics of kinematic parameters in a virtual context in comparison to a physical context. Kinematics and kinetics were captured while the children performed arm movements directed towards both virtual and physical targets. The children's movement precision improved, their centre of pressure paths decreased, as did the variability in maximal shoulder angles when reaching for virtual objects. Transfer to a situation with physical targets was mainly indicated by increased movement smoothness. Training with motion interactive games seems to improve arm motor control in children with CP. The results highlight the importance of considering both the context and the task itself when investigating kinematic parameters.

  2. The biomechanical assessment of the cervical inter-vertebral kinematics, between DDD patients ICR based study

    Science.gov (United States)

    Saveh, Amir Hossein; Zali, Ali Reza; Seddighi, Amir Saeed; Zarghi, Afsaneh; Chizari, Mahmoud; Hanafiah, Yussof

    2012-01-01

    Abstract: It is very important to pay more attention to spine from the biomechanical perspective. It would allow the analysis of initial conditions of the vertebral disc degeneration syndrome and adopting of normal spine kinematics to compare and match it with a degenerated disc and providing a biomechanical index as an indicator for the conduct of any surgical intervention including arthroplasty to maximize restoring spinal biomechanical motion. It is clear that the head movement is possible with the help of muscles. However, the shape and type of motion depends on the structure and shape of the cervical spine and the interaction between them. Cervical spine kinematics depends on the anatomy of the bones and joints. Bazhdok et al (2000) investigated the cervical kinematics and mechanical behavior of the spine and its anatomical connections. They have examined the atlanto- occipital joint motion during flexion-extension and rotation as well as the mechanism of paradoxical motion of atlanto- axial joint by radiography. Bifalkou et al (2011) studied the inter-vertebral motion based on arc kinematic commentary of video fluoroscopy. They showed that the diagnosis of biomechanical instability can be done based on the kinematic examination of the spine obtained in sagittal images. They also declared that the fluoroscopy can be used as a tool for study. Using an automated algorithm, image adaption was carried out and the motion direction of vertebrae was tracked. In the present study, some patients were selected among patients with cervical disc degeneration. Following imaging by fluoroscopy, the instantaneous center of the spinal action was calculated. It was used as a biomechanical criterion and the treatment group was compared with the healthy group. The loci of the instantaneous centers of the two groups were compared and its difference with the value of healthy group was calculated. A biomechanical criterion was introduced as a basis for comparison of normal and

  3. Exclusive measurements of quasi-free proton scattering reactions in inverse and complete kinematics

    Directory of Open Access Journals (Sweden)

    V. Panin

    2016-02-01

    Full Text Available Quasi-free scattering reactions of the type (p,2p were measured for the first time exclusively in complete and inverse kinematics, using a 12C beam at an energy of ∼400 MeV/u as a benchmark. This new technique has been developed to study the single-particle structure of exotic nuclei in experiments with radioactive-ion beams. The outgoing pair of protons and the fragments were measured simultaneously, enabling an unambiguous identification of the reaction channels and a redundant measurement of the kinematic observables. Both valence and deeply-bound nucleon orbits are probed, including those leading to unbound states of the daughter nucleus. Exclusive (p,2p cross sections of 15.8(18 mb, 1.9(2 mb and 1.5(2 mb to the low-lying 0p-hole states overlapping with the ground state (3/2− and with the bound excited states of 11B at 2.125 MeV (1/2− and 5.02 MeV (3/2−, respectively, were determined via γ-ray spectroscopy. Particle-unstable deep-hole states, corresponding to proton removal from the 0s-orbital, were studied via the invariant-mass technique. Cross sections and momentum distributions were extracted and compared to theoretical calculations employing the eikonal formalism. The obtained results are in a good agreement with this theory and with direct-kinematics experiments. The dependence of the proton–proton scattering kinematics on the internal momentum of the struck proton and on its separation energy was investigated for the first time in inverse kinematics employing a large-acceptance measurement.

  4. Listener perception of the effect of abdominal kinematic directives on respiratory behavior in female classical singing.

    Science.gov (United States)

    Collyer, Sally; Kenny, Dianna T; Archer, Michaele

    2011-01-01

    Breath management training in classical singing is becoming increasingly physiologically focused, despite evidence that directives focusing on chest-wall kinematic (ribcage and abdominal) behavior effect minimal change in acoustical measures of singing. A direct and proportionate relationship between breathing behavior and vocal quality is important in singing training because singing teachers rely primarily on changes in sound quality to assess the efficacy of breath management modification. Pedagogical opinion is also strongly divided over whether the strategy of retarding the reduction in abdominal dimension during singing has a negative effect on vocal quality. This study investigated whether changes in abdominal kinematic strategy were perceptible and whether listeners preferred a particular strategy. Fourteen experienced singing teachers and vocal coaches assessed audio samples of five female classical singers whose respiratory kinematic patterns during singing had been recorded habitually and under two simple, dichotomous directives: Gradually drawing the abdomen inward and gradually expanding the abdomen, during each phrase. Listeners rated the singers on standard of singing and of breath management. Ratings analysis took into consideration changes in kinematic behavior under each directive determined from the respiratory recordings. Listener ratings for two singers were unaffected by directive. For three singers, ratings were lower when the directive opposed habitual kinematic behavior. The results did not support the pedagogical assumption of a direct and proportional link between respiratory behavior and standard of singing or that the abdomen-outward strategy was deleterious to vocal quality. The findings demonstrate the importance of considering habitual breathing behavior in both research and pedagogical contexts. Copyright © 2011 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  5. Wheelchair propulsion kinematics in beginners and expert users: influence of wheelchair settings.

    Science.gov (United States)

    Gorce, P; Louis, N

    2012-01-01

    Biomechanical studies have linked the handrim wheelchair propulsion with a prevalence of upper limb musculoskeletal disorders. The purpose of this study was to examine the influence of the wheelchair settings on upper limb kinematics during wheelchair propulsion. Recordings were made under various wheelchair configuration conditions to understand the effect of wheelchair settings on kinematics parameters such shoulder, elbow and wrist angles. Ten experts and ten beginners' subjects propelled an experimental wheelchair on a roller ergometer system at a comfortable speed. Twelve wheelchair configurations were tested. Kinematics were recorded for each configuration. Based on the hand position relatively to the handrim, the main kinematic parameters of wheelchair propulsion were investigated on the whole propulsion cycle and a key event such as handrim contact and release. Compared to the beginner subjects, all the experts' subjects generally present higher joint amplitude and propulsion speeds. Seat height and antero-posterior axle position influence usage of the hand-rim, timing parameters and configurations of upper limb joints. Results seem to confirm that low and backward seat position allow a greater efficiency. Nevertheless, according that proximity of joint limit is a well known factor of musculoskeletal disorders, our results let us think that too low and backward seat position, increasing joints positions and amplitudes, could increase the risk of upper limb injuries in relation with manual wheelchair propulsion. Kinematic differences highlight that future studies on wheelchair propulsion should only be done with impaired experienced subjects. Furthermore, this study provides indications on how wheelchair settings can be used for upper limb injury prevention. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Direct kinematics solution architectures for industrial robot manipulators: Bit-serial versus parallel

    Science.gov (United States)

    Lee, J.; Kim, K.

    1991-01-01

    A Very Large Scale Integration (VLSI) architecture for robot direct kinematic computation suitable for industrial robot manipulators was investigated. The Denavit-Hartenberg transformations are reviewed to exploit a proper processing element, namely an augmented CORDIC. Specifically, two distinct implementations are elaborated on, such as the bit-serial and parallel. Performance of each scheme is analyzed with respect to the time to compute one location of the end-effector of a 6-links manipulator, and the number of transistors required.

  7. Direct kinematics solution architectures for industrial robot manipulators: Bit-serial versus parallel

    Science.gov (United States)

    Lee, J.; Kim, K.

    A Very Large Scale Integration (VLSI) architecture for robot direct kinematic computation suitable for industrial robot manipulators was investigated. The Denavit-Hartenberg transformations are reviewed to exploit a proper processing element, namely an augmented CORDIC. Specifically, two distinct implementations are elaborated on, such as the bit-serial and parallel. Performance of each scheme is analyzed with respect to the time to compute one location of the end-effector of a 6-links manipulator, and the number of transistors required.

  8. Kinematic Differences between Set- and Jump-Shot Motions in Basketball

    OpenAIRE

    Hiroki Okubo; Mont Hubbard

    2018-01-01

    Shooting arm motions at release in one-hand set and jump basketball shots have been analyzed using a kinematic model. Set and jump shots are classified by the vertical velocity and acceleration of the shooter’s shooting-side shoulder at release. The two-dimensional three-segment model includes the vertical shooting-side shoulder velocity and acceleration. Numerical simulation investigates the effect of shoulder motion. Release backspin angular velocity can be described as a function of the ve...

  9. Validation and structural analysis of the kinematics concept test

    Directory of Open Access Journals (Sweden)

    A. Lichtenberger

    2017-04-01

    Full Text Available The kinematics concept test (KCT is a multiple-choice test designed to evaluate students’ conceptual understanding of kinematics at the high school level. The test comprises 49 multiple-choice items about velocity and acceleration, which are based on seven kinematic concepts and which make use of three different representations. In the first part of this article we describe the development and the validation process of the KCT. We applied the KCT to 338 Swiss high school students who attended traditional teaching in kinematics. We analyzed the response data to provide the psychometric properties of the test. In the second part we present the results of a structural analysis of the test. An exploratory factor analysis of 664 student answers finally uncovered the seven kinematics concepts as factors. However, the analysis revealed a hierarchical structure of concepts. At the higher level, mathematical concepts group together, and then split up into physics concepts at the lower level. Furthermore, students who seem to understand a concept in one representation have difficulties transferring the concept to similar problems in another representation. Both results have implications for teaching kinematics. First, teaching mathematical concepts beforehand might be beneficial for learning kinematics. Second, instructions have to be designed to teach students the change between different representations.

  10. Validation and structural analysis of the kinematics concept test

    Science.gov (United States)

    Lichtenberger, A.; Wagner, C.; Hofer, S. I.; Stern, E.; Vaterlaus, A.

    2017-06-01

    The kinematics concept test (KCT) is a multiple-choice test designed to evaluate students' conceptual understanding of kinematics at the high school level. The test comprises 49 multiple-choice items about velocity and acceleration, which are based on seven kinematic concepts and which make use of three different representations. In the first part of this article we describe the development and the validation process of the KCT. We applied the KCT to 338 Swiss high school students who attended traditional teaching in kinematics. We analyzed the response data to provide the psychometric properties of the test. In the second part we present the results of a structural analysis of the test. An exploratory factor analysis of 664 student answers finally uncovered the seven kinematics concepts as factors. However, the analysis revealed a hierarchical structure of concepts. At the higher level, mathematical concepts group together, and then split up into physics concepts at the lower level. Furthermore, students who seem to understand a concept in one representation have difficulties transferring the concept to similar problems in another representation. Both results have implications for teaching kinematics. First, teaching mathematical concepts beforehand might be beneficial for learning kinematics. Second, instructions have to be designed to teach students the change between different representations.

  11. Kinematic design considerations for minimally invasive surgical robots: an overview.

    Science.gov (United States)

    Kuo, Chin-Hsing; Dai, Jian S; Dasgupta, Prokar

    2012-06-01

    Kinematic design is a predominant phase in the design of robotic manipulators for minimally invasive surgery (MIS). However, an extensive overview of the kinematic design issues for MIS robots is not yet available to both mechanisms and robotics communities. Hundreds of archival reports and articles on robotic systems for MIS are reviewed and studied. In particular, the kinematic design considerations and mechanism development described in the literature for existing robots are focused on. The general kinematic design goals, design requirements, and design preferences for MIS robots are defined. An MIS-specialized mechanism, namely the remote center-of-motion (RCM) mechanism, is revisited and studied. Accordingly, based on the RCM mechanism types, a classification for MIS robots is provided. A comparison between eight different RCM types is given. Finally, several open challenges for the kinematic design of MIS robotic manipulators are discussed. This work provides a detailed survey of the kinematic design of MIS robots, addresses the research opportunity in MIS robots for kinematicians, and clarifies the kinematic point of view to MIS robots as a reference for the medical community. Copyright © 2012 John Wiley & Sons, Ltd.

  12. Effects of the kinematic viscosity and surface tension on the bubble take-off period in a catalase-hydrogen peroxide system.

    Science.gov (United States)

    Sasaki, Satoshi; Iida, Yoshinori

    2009-06-01

    The effect of kinematic viscosity and surface tension of the solution was investigated by adding catalase, glucose oxidase, or glucose on the bubble movement in a catalase-hydrogen peroxide system. The kinematic viscosity was measured using a Cannon-Fenske kinematic viscometer. The surface tension of the solution was measured by the Wilhelmy method using a self-made apparatus. The effects of the hole diameter/cell wall thickness, catalase concentration, glucose concentration, and glucose oxidase concentration on the kinematic viscosity, surface tension, and bubble take-off period were investigated. With our system, the effects of the changes in the solution materiality on the bubble take-off period were proven to be very small in comparison to the change in the oxygen-producing rate.

  13. Dose exposure work planning using DMU kinematics tools

    International Nuclear Information System (INIS)

    Rosli Darmawan

    2010-01-01

    The study on the possibility of using DMU Kinematics module in CAE tools for dose exposure work planning was carried out. A case scenario was created using 3D CAD software and transferred to DMU Kinematics module in CAE software. A work plan was created using DMU Kinematics tools and animated to simulate a real time scenario. Data on the phantom position against the radioactive source was collected by activating positioning sensors in the module. The data was used to estimate dose rate exposure for the phantom. The results can be used to plan the safest and optimum procedures in carrying out the radiation related task. (author)

  14. An adaptive inverse kinematics algorithm for robot manipulators

    Science.gov (United States)

    Colbaugh, R.; Glass, K.; Seraji, H.

    1990-01-01

    An adaptive algorithm for solving the inverse kinematics problem for robot manipulators is presented. The algorithm is derived using model reference adaptive control (MRAC) theory and is computationally efficient for online applications. The scheme requires no a priori knowledge of the kinematics of the robot if Cartesian end-effector sensing is available, and it requires knowledge of only the forward kinematics if joint position sensing is used. Computer simulation results are given for the redundant seven-DOF robotics research arm, demonstrating that the proposed algorithm yields accurate joint angle trajectories for a given end-effector position/orientation trajectory.

  15. Investigation of subcooled boiling onset propagation

    International Nuclear Information System (INIS)

    Josipovic, M.; Riznic, J.; Vrhovac, M.; Spasojevic, D.

    1986-01-01

    In paper is presented a method for thermohydrodynamicaly and kinematically nonequilibrium two-phase mixture flow basic process and phenomena investigation, during chosen transient. Comparison and brief discussion of results on experimental facility KVP are included. (author)

  16. Influence of kinematic cuts on the net charge distribution

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Hannah [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Institut für Theoretische Physik, Goethe Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Oliinychenko, Dmytro [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Bogolyubov Institute for Theoretical Physics, Kiev 03680 (Ukraine); Steinheimer, Jan [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Bleicher, Marcus [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Institut für Theoretische Physik, Goethe Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany)

    2016-12-15

    The higher moments of the net charge distributions, e.g. the skewness and kurtosis, are studied within an infinite hadronic matter calculation in a transport approach. By dividing the box into several parts, the volume dependence of the fluctuations is investigated. After confirming that the initial distributions follow the expectations from a binomial distribution, the influence of quantum number conservation in this case the net charge in the system on the higher moments is evaluated. For this purpose, the composition of the hadron gas is adjusted and only pions and ρ mesons are simulated to investigate the charge conservation effect. In addition, the effect of imposing kinematic cuts in momentum space is analysed. The role of resonance excitations and decays on the higher moments can also be studied within this model. This work is highly relevant to understand the experimental measurements of higher moments obtained in the RHIC beam energy scan and their comparison to lattice results and other theoretical calculations assuming infinite matter.

  17. EFFECTS OF DISTANCE SPECIALIZATION ON THE BACKSTROKE SWIMMING KINEMATICS

    Directory of Open Access Journals (Sweden)

    Cortesi Matteo

    2012-09-01

    Full Text Available The purpose of the present study was to investigate different biomechanical variables of backstroke technique in swimmers specialized in different distance events, in order to investigate the capacity to modify the timing of the arm stroke when changing the swimming velocity from sub-maximal to maximal. Two 25-m backstroke trials respectively at 70% of maximum velocity (V70 and at 100% of maximum velocity (Vmax were performed by 9 200-m distance swimmers and 9 50-m distance swimmers. Swimming velocity, stroke length, stroke rate, duration of different phases of the arm stroke and selected kinematic variables were assessed in both cases. In the 50-m distance swimmers, the duration of the propulsive phase at Vmax, expressed as a percentage of the duration of the total underwater arm stroke, increased significantly (p = 0.001 with increasing swimming velocity. Specifically, both the pull and push phases were fundamental in the increase of duration of the propulsive phase. When compared to 200-m specialists, 50-m distance swimmers seem to be more able to modify their arm stroke phases duration when increasing the swimming velocity in backstroke

  18. DETECTING TRIAXIALITY IN THE GALACTIC DARK MATTER HALO THROUGH STELLAR KINEMATICS. II. DEPENDENCE ON NATURE DARK MATTER AND GRAVITY

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Niño, Armando; Pichardo, Barbara; Valenzuela, Octavio [Instituto de Astronomía, Universidad Nacional Autónoma de México, A.P. 70-264, 04510, México, D.F., Universitaria, D.F., México (Mexico); Martínez-Medina, Luis A., E-mail: barbara@astro.unam.mx, E-mail: octavio@astro.unam.mx [Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN, A.P. 14-740, 07000 México D.F., México (Mexico)

    2015-05-20

    Recent studies have presented evidence that the Milky Way global potential may be non-spherical. In this case, the assembling process of the Galaxy may have left long-lasting stellar halo kinematic fossils due to the shape of the dark matter halo, potentially originated by orbital resonances. We further investigate such a possibility, now considering potential models further away from ΛCDM halos, like scalar field dark matter halos and Modified Newtonian Dynamics (MOND), and including several other factors that may mimic the emergence and permanence of kinematic groups, such as a spherical and triaxial halo with an embedded disk potential. We find that regardless of the density profile (DM nature), kinematic groups only appear in the presence of a triaxial halo potential. For the case of a MOND-like gravity theory no kinematic structure is present. We conclude that the detection of these kinematic stellar groups could confirm the predicted triaxiality of dark halos in cosmological galaxy formation scenarios.

  19. Virtual sine arm kinematic mount system

    International Nuclear Information System (INIS)

    Xu, Z.; Randall, K.J.

    1997-01-01

    A novel kinematic mount system for a vertical focusing mirror of the soft x-ray spectroscopy beamline at the Advanced Photon Source is described. The system contains three points in a horizontal plane. Each point consists of two horizontal linear precision stages, a spherical ball bearing, and a vertical precision stage. The horizontal linear stages are aligned orthogonally and are conjoined by a spherical ball bearing, supported by the vertical linear stage at each point. The position of each confined horizontal stage is controlled by a motorized micrometer head by spring-loading the flat tip of the micrometer head onto a tooling ball fixing on the carriage of the stage. A virtual sine arm is formed by tilting the upstream horizontal stage down and the two downstream horizontal stages up by a small angle. The fine pitch motion is achieved by adjusting the upstream stage. This supporting structure is extremely steady due to a relatively large span across the supporting points and yields extremely high resolution on the pitch motion. With a one degree tilt and a microstepping motor, the authors achieved a 0.4 nanoradian resolution on the mirror pitch motion

  20. Bat flight: aerodynamics, kinematics and flight morphology.

    Science.gov (United States)

    Hedenström, Anders; Johansson, L Christoffer

    2015-03-01

    Bats evolved the ability of powered flight more than 50 million years ago. The modern bat is an efficient flyer and recent research on bat flight has revealed many intriguing facts. By using particle image velocimetry to visualize wake vortices, both the magnitude and time-history of aerodynamic forces can be estimated. At most speeds the downstroke generates both lift and thrust, whereas the function of the upstroke changes with forward flight speed. At hovering and slow speed bats use a leading edge vortex to enhance the lift beyond that allowed by steady aerodynamics and an inverted wing during the upstroke to further aid weight support. The bat wing and its skeleton exhibit many features and control mechanisms that are presumed to improve flight performance. Whereas bats appear aerodynamically less efficient than birds when it comes to cruising flight, they have the edge over birds when it comes to manoeuvring. There is a direct relationship between kinematics and the aerodynamic performance, but there is still a lack of knowledge about how (and if) the bat controls the movements and shape (planform and camber) of the wing. Considering the relatively few bat species whose aerodynamic tracks have been characterized, there is scope for new discoveries and a need to study species representing more extreme positions in the bat morphospace. © 2015. Published by The Company of Biologists Ltd.

  1. A dynamical systems analysis of the kinematics of time-periodic vortex shedding past a circular cylinder

    Science.gov (United States)

    Ottino, Julio M.

    1991-01-01

    Computer flow simulation aided by dynamical systems analysis is used to investigate the kinematics of time-periodic vortex shedding past a two-dimensional circular cylinder in the context of the following general questions: (1) Is a dynamical systems viewpoint useful in the understanding of this and similar problems involving time-periodic shedding behind bluff bodies; and (2) Is it indeed possible, by adopting such a point of view, to complement previous analyses or to understand kinematical aspects of the vortex shedding process that somehow remained hidden in previous approaches. We argue that the answers to these questions are positive. Results are described.

  2. The influence of airfoil kinematics on the formation of leading-edge vortices in bio-inspired flight

    Energy Technology Data Exchange (ETDEWEB)

    Rival, David; Prangemeier, Tim; Tropea, Cameron [Technische Universitaet Darmstadt (Germany). Institute of Fluid Mechanics and Aerodynamics

    2009-05-15

    The formation process of leading-edge vortices has been investigated experimentally using Particle Image Velocimetry. Various airfoil kinematics have been tested, including asymmetric and peak-shifted plunging motions, and are evaluated for Re = 30,000 and a reduced frequency range of 0.2{<=}k{<=}0.33. By measuring the growth in the leading-edge vortex during the dynamic-stall process, the vortex pinch-off process is examined based on the concept of an optimal vortex formation time. The various kinematics are then evaluated with respect to their associated vortex strength, timing and convection into the wake. (orig.)

  3. Earthquake response analyses of soil-structure system considering kinematic interaction

    International Nuclear Information System (INIS)

    Murakami, H.; Yokono, K.; Miura, S.; Ishii, K.

    1985-01-01

    Improvement of soil-structure interaction analysis has been one of major concerns in earthquake engineering field, especially in nuclear industries, to evaluate the safety of structure accurately under earthquake events. This research aims to develop a rational analytical tool which considers effect of the 'kinematic interaction' satisfactory with a proposed simple low-pass filter. In this paper, first the effect of the kinematic interaction is investigated based on earthquake response analysis of a reactor building using the practical design models: the spring-mass-dashpot system and the 'lattice model', in which a building and soil medium are modeled by a system of lumped masses. Next, the filter is developed based on parametrical studies with various sizes of depth and width of foundations embedded in two-layers soil, which represents more general soil condition in practical designs compared with a homogeneous soil medium. (orig.)

  4. IMPROVEMENT OF GRAPH INTERPRETATION ABILITY USING HYPERTEXT-ASSISTED KINEMATIC LEARNING AND FORMAL THINKING ABILITY

    Directory of Open Access Journals (Sweden)

    S. R. Manurung

    2018-01-01

    Full Text Available The effectiveness of hypertext media in improving graph interpretation ability is investigated in this paper. In addition, joint ability of the formal thinking to improve the graph ability of prospective students is considered. The research design used is the one-group pretest-posttest experimental design is carried out in the research by taking 36 students on from Physics Education Program in one institute for teacher education in Medan. The test consists of graph interpretation ability test in the topic of kinematics and Test of Logical Thinking (TOLT or formal thinking before learning and graph interpretation ability test after learning. The data are then analysed by using SPSS based two ways Analisys of Variance (ANOVA method. The results show that the ability to interpretate graph is significantly improved by using hypertext media assisted kinematic learning.

  5. Kinematic and dynamic modeling and approximate analysis of a roller chain drive

    DEFF Research Database (Denmark)

    Fuglede, Niels; Thomsen, Jon Juel

    2016-01-01

    for analytical studies of the coupled motion of the chain spans and driven sprocket. Parametric excitation of the spans come from sprocket angular displacements, and the driven sprocket acts as a boundary which can be compliant in the axial direction. External transverse excitation of the spans comes from...... polygonal action, and is treated through kinematic forcing at the moving string boundaries. Perturbation analysis of the model is carried out using the method of multiple scales. Results show a multitude of internal and external resonance conditions, and some examples are presented of both decoupled...... and coupled motion. Together, the kinematic and dynamic model are aimed toward providing a framework for conducting and understanding both numerical, and experimental investigations of roller chain drive dynamics....

  6. Kinematics of the quaternary fault zones in the Kyeongju area of the southeastern Korean Peninsula

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Seob; Lee, Byeong Hyui; Kwon, Hyeok Sang [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)] (and others)

    1998-09-15

    The purposes of this study are to interpret the kinematics of the Quaternary fault zones in the Kyeongju area, to determine deformation mechanisms during faulting by analyzing micorstrucutres of fault rocks from the fault zones, and to unravel the technic evaluation of the regional fault structures in the Kyeongju-Wolsung area. The scope of this study consists of ; collection and interpretation of structural elements through a detailed geologic investigation on the Quaternary faults in the Kyeongju-Wolsung area, interpretation of fault-rock microstructures from the fault zones using oriented samples of faults rocks, determination of deformation processes and mechanisms of the fault rocks and, interpretation of faulting kinematics and evaluation of the fault zones.

  7. Kinematics of the quaternary fault zones in the Kyeongju area of the southeastern Korean Peninsula

    International Nuclear Information System (INIS)

    Kim, In Seob; Lee, Byeong Hyui; Kwon, Hyeok Sang

    1998-09-01

    The purposes of this study are to interpret the kinematics of the Quaternary fault zones in the Kyeongju area, to determine deformation mechanisms during faulting by analyzing micorstrucutres of fault rocks from the fault zones, and to unravel the technic evaluation of the regional fault structures in the Kyeongju-Wolsung area. The scope of this study consists of ; collection and interpretation of structural elements through a detailed geologic investigation on the Quaternary faults in the Kyeongju-Wolsung area, interpretation of fault-rock microstructures from the fault zones using oriented samples of faults rocks, determination of deformation processes and mechanisms of the fault rocks and, interpretation of faulting kinematics and evaluation of the fault zones

  8. Non-kinematic Flux-transport Dynamos Including the Effects of Diffusivity Quenching

    Energy Technology Data Exchange (ETDEWEB)

    Ichimura, Chiaki; Yokoyama, Takaaki [Department of Earth and Planetary Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2017-04-10

    Turbulent magnetic diffusivity is quenched when strong magnetic fields suppress turbulent motion in a phenomenon known as diffusivity quenching. Diffusivity quenching can provide a mechanism for amplifying magnetic field and influencing global velocity fields through Lorentz force feedback. To investigate this effect, we conducted mean field flux-transport dynamo simulations that included the effects of diffusivity quenching in a non-kinematic regime. We found that toroidal magnetic field strength is amplified by up to approximately 1.5 times in the convection zone as a result of diffusivity quenching. This amplification is much weaker than that in kinematic cases as a result of Lorentz force feedback on the system’s differential rotation. While amplified toroidal fields lead to the suppression of equatorward meridional flow locally near the base of the convection zone, large-scale equatorward transport of magnetic flux via meridional flow, which is the essential process of the flux-transport dynamo, is sustainable in our calculations.

  9. Global-local optimization of flapping kinematics in hovering flight

    KAUST Repository

    Ghommem, Mehdi; Hajj, M. R.; Mook, Dean T.; Stanford, Bret K.; Bé ran, Philip S.; Watson, Layne T.

    2013-01-01

    The kinematics of a hovering wing are optimized by combining the 2-d unsteady vortex lattice method with a hybrid of global and local optimization algorithms. The objective is to minimize the required aerodynamic power under a lift constraint. The hybrid optimization is used to efficiently navigate the complex design space due to wing-wake interference present in hovering aerodynamics. The flapping wing is chosen so that its chord length and flapping frequency match the morphological and flight properties of two insects with different masses. The results suggest that imposing a delay between the different oscillatory motions defining the flapping kinematics, and controlling the way through which the wing rotates at the end of each half stroke can improve aerodynamic power under a lift constraint. Furthermore, our optimization analysis identified optimal kinematics that agree fairly well with observed insect kinematics, as well as previously published numerical results.

  10. Analytical kinematics analysis and synthesis of planar mechanisms

    CERN Document Server

    Gans, Deborah

    2013-01-01

    Using computational techniques and a complex variable formulation, this book teaches the student of kinematics to handle increasingly difficult problems in both the analysis and design of mechanisms all based on the fundamental loop closure equation.

  11. Improving vertex position determination by using a kinematic fit

    International Nuclear Information System (INIS)

    Forden, G.E.; Saxon, D.H.

    1985-05-01

    A method is developed for improving decay vertex reconstruction by using kinematic fits. This is applied to generated charm meson decays. An improvement of 16% in the vertex position measurement along the flight path is achieved. (author)

  12. Cluster algebras in scattering amplitudes with special 2D kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Marcus A.C. [Institut de Physique Theorique, CEA-Saclay, Gif-sur-Yvette Cedex (France)

    2014-02-15

    We study the cluster algebra of the kinematic configuration space Conf{sub n}(P{sup 3}P3) of an n-particle scattering amplitude restricted to the special 2D kinematics. We found that the n-point two-loop MHVremainder function in special 2D kinematics depends on a selection of the X-coordinates that are part of a special structure of the cluster algebra related to snake triangulations of polygons. This structure forms a necklace of hypercube beads in the corresponding Stasheff polytope. Furthermore at n = 12, the cluster algebra and the selection of theX-coordinates in special2Dkinematics replicates the cluster algebra and the selection of X-coordinates of the n = 6 two-loop MHV amplitude in 4D kinematics. (orig.)

  13. Relationship among shoulder proprioception, kinematics, and pain after stroke

    NARCIS (Netherlands)

    Niessen, M.H.M.; Veeger, H.E.J.; Meskers, C.G.M.; Koppe, P.A.; Konijnenbelt, M.H.; Janssen, T.W.J.

    2009-01-01

    Niessen MH, Veeger DH, Meskers CG, Koppe PA, Konijnenbelt MH, Janssen TW. Relationship among shoulder proprioception, kinematics, and pain after stroke. Objective: To identify a possible relationship among chronic poststroke shoulder pain (PSSP), scapular resting pose, and shoulder proprioception.

  14. Global-local optimization of flapping kinematics in hovering flight

    KAUST Repository

    Ghommem, Mehdi

    2013-06-01

    The kinematics of a hovering wing are optimized by combining the 2-d unsteady vortex lattice method with a hybrid of global and local optimization algorithms. The objective is to minimize the required aerodynamic power under a lift constraint. The hybrid optimization is used to efficiently navigate the complex design space due to wing-wake interference present in hovering aerodynamics. The flapping wing is chosen so that its chord length and flapping frequency match the morphological and flight properties of two insects with different masses. The results suggest that imposing a delay between the different oscillatory motions defining the flapping kinematics, and controlling the way through which the wing rotates at the end of each half stroke can improve aerodynamic power under a lift constraint. Furthermore, our optimization analysis identified optimal kinematics that agree fairly well with observed insect kinematics, as well as previously published numerical results.

  15. Agent Control for Reconfigurable Open Kinematic Chain Manipulators

    Directory of Open Access Journals (Sweden)

    Janez Sluga

    2013-10-01

    Full Text Available This paper presents a method for the autonomous control of differently structured open kinematic chains based on multi-agent system technology. The appropriate level of distributing local autonomy (agents to a manipulative structure is defined, which makes it possible to dynamically change the number, type and structure of manipulative components without modifying their behavioural logic. To achieve fast reconfigurable and scalable manipulative systems, a new multi-agent method is developed for controlling the manipulator kinematics. The new method enables independent manipulator structure from the control system because of its structural and system modularity. The proposed method consists of kinematic equations for use in an agent environment, agent motion-planning algorithms, evaluation functions, agent control logic and kinematic algorithms. The results of simulations and real-world experiments demonstrate the usefulness of the approach for different non-redundant and redundant manipulation structures.

  16. Synthesis of Algorithm for Range Measurement Equipment to Track Maneuvering Aircraft Using Data on Its Dynamic and Kinematic Parameters

    Science.gov (United States)

    Pudovkin, A. P.; Panasyuk, Yu N.; Danilov, S. N.; Moskvitin, S. P.

    2018-05-01

    The problem of improving automated air traffic control systems is considered through the example of the operation algorithm synthesis for a range measurement channel to track the aircraft, using its kinematic and dynamic parameters. The choice of the state and observation models has been justified, the computer simulations have been performed and the results of the investigated algorithms have been obtained.

  17. Elastic moduli of sandstones saturated with a range of pore fluids correlated with kinematic viscosity and frequency ratio

    DEFF Research Database (Denmark)

    Sørensen, Morten Kanne; Fabricius, Ida Lykke

    2011-01-01

    . The purpose of this study is to investigate if frame parameters can be extracted from air saturated measurements in sandstones, because earlier studies have shown that air may have a non-negligible effect on carbonates due to the high kinematic viscosity of air (Fabricius et al., 2010)....

  18. Effects of thigh holster use on kinematics and kinetics of active duty police officers.

    Science.gov (United States)

    Larsen, Louise Bæk; Tranberg, Roy; Ramstrand, Nerrolyn

    2016-08-01

    Body armour, duty belts and belt mounted holsters are standard equipment used by the Swedish police and have been shown to affect performance of police specific tasks, to decrease mobility and to potentially influence back pain. This study aimed to investigate the effects on gait kinematics and kinetics associated with use of an alternate load carriage system incorporating a thigh holster. Kinematic, kinetic and temporospatial data were collected using three dimensional gait analysis. Walking tests were conducted with nineteen active duty police officers under three different load carriage conditions: a) body armour and duty belt, b) load bearing vest, body armour and thigh holster and c) no equipment (control). No significant differences between testing conditions were found for temporospatial parameters. Range of trunk rotation was reduced for both load carriage conditions compared to the control condition (p<0.017). Range of hip rotation was more similar to the control condition when wearing thigh holster rather than the belt mounted hip holster (p<0.017). Moments and powers for both left and right ankles were significantly greater for both of the load carriage conditions compared to the control condition (p<0.017). This study confirms that occupational loads carried by police have a significant effect on gait kinematics and kinetics. Although small differences were observed between the two load carriage conditions investigated in this study, results do not overwhelmingly support selection of one design over the other. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Effects of prophylactic knee bracing on knee joint kinetics and kinematics during netball specific movements.

    Science.gov (United States)

    Sinclair, Jonathan K; Vincent, Hayley; Richards, Jim D

    2017-01-01

    To investigate the effects of a prophylactic knee brace on knee joint kinetics and kinematics during netball specific movements. Repeated measures. Laboratory. Twenty university first team level female netball players. Participants performed three movements, run, cut and vertical jump under two conditions (brace and no-brace). 3-D knee joint kinetics and kinematics were measured using an eight-camera motion analysis system. Knee joint kinetics and kinematics were examined using 2 × 3 repeated measures ANOVA whilst the subjective ratings of comfort and stability were investigated using chi-squared tests. The results showed no differences (p > 0.05) in knee joint kinetics. However the internal/external rotation range of motion was significantly (p < 0.05) reduced when wearing the brace in all movements. The subjective ratings of stability revealed that netballers felt that the knee brace improved knee stability in all movements. Further study is required to determine whether reductions in transverse plane knee range of motion serve to attenuate the risk from injury in netballers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Kinematic power corrections in off-forward hard reactions.

    Science.gov (United States)

    Braun, V M; Manashov, A N

    2011-11-11

    We develop a general approach to the calculation of kinematic corrections ∝t/Q(2), m(2)/Q(2) in hard processes which involve momentum transfer from the initial to the final hadron state. As the principal result, the complete expression is derived for the time-ordered product of two electromagnetic currents that includes all kinematic corrections to twist-four accuracy. The results are immediately applicable, e.g., to the studies of deeply virtual Compton scattering.

  1. Inverse kinematics problem in robotics using neural networks

    Science.gov (United States)

    Choi, Benjamin B.; Lawrence, Charles

    1992-01-01

    In this paper, Multilayer Feedforward Networks are applied to the robot inverse kinematic problem. The networks are trained with endeffector position and joint angles. After training, performance is measured by having the network generate joint angles for arbitrary endeffector trajectories. A 3-degree-of-freedom (DOF) spatial manipulator is used for the study. It is found that neural networks provide a simple and effective way to both model the manipulator inverse kinematics and circumvent the problems associated with algorithmic solution methods.

  2. Anatomical kinematic constraints: consequences on muscular forces and joint reactions

    OpenAIRE

    MOISSENET, F; CHEZE, L; DUMAS, R

    2011-01-01

    This paper presents a method to determine musculo-tendon forces and joint reactions during gait, using a 3D right leg model with 5 DoFs: spherical joint at the hip and parallel mechanisms at both knee and ankle. A typical set of natural coordinates is used to obtain the dynamic equations. First, using a global optimization method, "anatomical" kinematic constraints (i.e., parallel mechanisms) are applied on the kinematics obtained from motion capture data. Consistent derivatives are computed ...

  3. Kinematics of roller chain drives - Exact and approximate analysis

    DEFF Research Database (Denmark)

    Fuglede, Niels; Thomsen, Jon Juel

    2016-01-01

    An exact and approximate kinematic analysis of a roller chain drive modeled as a four-bar mechanism is presented. The span connects the sprockets such that they rotate in the same direction, and the sprocket size, number of teeth, and shaft center distance can be arbitrary. The driven sprocket...... to be very good agreement. All together this gives new insights into the characteristics of chain drive kinematics and the influence of main design parameters....

  4. Numerical kinematic transformation calculations for a parallel link manipulator

    International Nuclear Information System (INIS)

    Killough, S.M.

    1993-01-01

    Parallel link manipulators are often considered for particular robotic applications because of the unique advantages they provide. Unfortunately, they have significant disadvantages with respect to calculating the kinematic transformations because of the high-order equations that must be solved. Presented is a manipulator design that exploits the mechanical advantages of parallel links yet also has a corresponding numerical kinematic solution that can be solved in real time on common microcomputers

  5. Kinematic control of redundant robots and the motion optimizability measure.

    Science.gov (United States)

    Li, L; Gruver, W A; Zhang, Q; Yang, Z

    2001-01-01

    This paper treats the kinematic control of manipulators with redundant degrees of freedom. We derive an analytical solution for the inverse kinematics that provides a means for accommodating joint velocity constraints in real time. We define the motion optimizability measure and use it to develop an efficient method for the optimization of joint trajectories subject to multiple criteria. An implementation of the method for a 7-dof experimental redundant robot is present.

  6. Altered Kinematics of Facial Emotion Expression and Emotion Recognition Deficits Are Unrelated in Parkinson's Disease.

    Science.gov (United States)

    Bologna, Matteo; Berardelli, Isabella; Paparella, Giulia; Marsili, Luca; Ricciardi, Lucia; Fabbrini, Giovanni; Berardelli, Alfredo

    2016-01-01

    Altered emotional processing, including reduced emotion facial expression and defective emotion recognition, has been reported in patients with Parkinson's disease (PD). However, few studies have objectively investigated facial expression abnormalities in PD using neurophysiological techniques. It is not known whether altered facial expression and recognition in PD are related. To investigate possible deficits in facial emotion expression and emotion recognition and their relationship, if any, in patients with PD. Eighteen patients with PD and 16 healthy controls were enrolled in this study. Facial expressions of emotion were recorded using a 3D optoelectronic system and analyzed using the facial action coding system. Possible deficits in emotion recognition were assessed using the Ekman test. Participants were assessed in one experimental session. Possible relationship between the kinematic variables of facial emotion expression, the Ekman test scores, and clinical and demographic data in patients were evaluated using the Spearman's test and multiple regression analysis. The facial expression of all six basic emotions had slower velocity and lower amplitude in patients in comparison to healthy controls (all P s facial expression kinematics and emotion recognition deficits were unrelated in patients (all P s > 0.05). Finally, no relationship emerged between kinematic variables of facial emotion expression, the Ekman test scores, and clinical and demographic data in patients (all P s > 0.05). The results in this study provide further evidence of altered emotional processing in PD. The lack of any correlation between altered facial emotion expression kinematics and emotion recognition deficits in patients suggests that these abnormalities are mediated by separate pathophysiological mechanisms.

  7. Kinematic Chains in Ski Jumping In-run Posture.

    Science.gov (United States)

    Janurová, Eva; Janura, Miroslav; Cabell, Lee; Svoboda, Zdeněk; Vařeka, Ivan; Elfmark, Milan

    2013-12-18

    The concept of kinematic chains has been systematically applied to biological systems since the 1950s. The course of a ski jump can be characterized as a change between closed and open kinematic chains. The purpose of this study was to determine a relationship between adjacent segments within the ski jumper's body's kinematic chain during the in-run phase of the ski jump. The in-run positions of 267 elite male ski jumpers who participated in the FIS World Cup events in Innsbruck, Austria, between 1992 and 2001 were analyzed (656 jumps). Two-dimensional (2-D) kinematic data were collected from the bodies of the subjects. Relationships between adjacent segments of the kinematic chain in the ski jumper's body at the in-run position are greater nearer the chain's ground contact. The coefficient of determination between the ankle and knee joint angles is 0.67. Changes in the segments' positions in the kinematic chain of the ski jumper's body are stable during longitudinal assessment. Changes in shank and thigh positions, in the sense of increase or decrease, are the same.

  8. Development of Calculation Algorithm for ECCS Kinematic Shock

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Chan; Yoon, Duk-Joo; Ha, Sang-Jun [KHNP-CRI, Daejeon (Korea, Republic of)

    2014-10-15

    The void fraction of inverted U-pipes in front of SI(Safety Injection) pumps impact on the pipe system of ECCS(Emergency Core Cooling Systems). This phenomena is called as 'Kinematic Shock'. The purpose of this paper is to achieve the more exactly calculation when the kinematic shock is calculated by simplified equation. The behavior of the void packet of the ECCS pipes is illustrated by the simplified (other name is kinematic shock equation).. The kinematic shock is defined as the depth of total length of void clusters in the pipes of ECCS when the void cluster is continually reached along the part of pipes in vertical direction. In this paper, the simplified equation is evaluated by comparing calculation error each other.]. The more exact methods of calculating the depth of the kinematic shock in ECCS is achieved. The error of kinematic shock calculation is strongly depended on the calculation search gap and the order of Taylor's expansion. From this study, to select the suitable search gap and the suitable calculation order, differential root method, secant method, and Taylor's expansion form are compared one another.

  9. Body Composition and Kinematic Analysis of the Grab Start in Youth Swimmers

    Directory of Open Access Journals (Sweden)

    Alptekin Ahmet

    2014-10-01

    Full Text Available The purposes of this study were to compare the kinematic variables in youth swimmers during the grab start between sexes and to investigate the relationship between body composition and kinematic variables of the participants. Six female (Mage = 13.71 ± 0.49 yrs and seven male (Mage = 14.00 ± 1.07 yrs swimmers participated in this study. All participants were required to perform grab start tests in random order (three trials by each participant, while the best attempt was analyzed. Nineteen kinematic parameters consisting of block time, flight time, flight distance, total time, total distance, horizontal and vertical displacement of the center of mass (CM at take-off, horizontal and vertical displacement of the CM at entry, height of take-off and entry, relative height of take-off, horizontal and vertical velocity of the CM at take-off, horizontal and vertical velocity of the CM at entry, angle of take-off, angle of entry and angle of knee at block were analyzed. Out of the 19 evaluated kinematic parameters, a statistical difference between the female and male group was found only in the total distance. Therefore, both female and male groups are considered as only one group and merged after analyzing the results. Statistical analysis showed positive and negative correlations between horizontal / vertical velocity of CM at take-off and several kinematic variables (e.g. angle of entry (rhorizontal = -.868, p=.000 / rvertical = .591, p=.02, total distance (rhorizontal = .594, p=.02 / rvertical = .54, p=.04, and height of take-off (rvertical = .888, p=.000, respectively. On the other hand, positive and negative correlations were found between somatotype components and several kinematic variables (e.g. horizontal displacement of CM at entry (rendomorphy = -.626, p=.013, angle of entry (rmesomorphy = -.686, p=.005 / rectomorphy = .52, p=.047, total distance (rendomorphy = -.626, p=.012, and height of take-off (rendomorphy = -.633, p=.011

  10. Exercise-induced muscle fatigue in the unaffected knee joint and its influence on postural control and lower limb kinematics in stroke patients

    Directory of Open Access Journals (Sweden)

    Sun Wook Park

    2017-01-01

    Full Text Available This study aimed to investigate the effects of exercise-induced muscle fatigue in the unaffected knee joint on postural control and kinematic changes in stroke patients. Forty participants (20 stroke patients, 20 age-matched healthy participants were recruited. To induce fatigue, maximum voluntary isometric contractions were performed in the unaffected knee joint in a Leg Extension Rehab exercise machine using the pneumatic resistance. We measured static and dynamic balance and lower-limb kinematics during gait. Changes in postural control parameters anteroposterior sway speed and total center of pressure distance differed significantly between the stroke and control groups. In addition, changes in gait kinematic parameters knee and ankle angles of initial contact differed significantly between stroke (paretic and non-paretic and control groups. Muscle fatigue in the unaffected knee and ankle impaired postural control and debilitates kinematic movement of ipsilateral and contralateral lower limbs, and may place the fatigued stroke patients at greater risk for falls.

  11. Computing broadband accelerograms using kinematic rupture modeling

    International Nuclear Information System (INIS)

    Ruiz Paredes, J.A.

    2007-05-01

    In order to make the broadband kinematic rupture modeling more realistic with respect to dynamic modeling, physical constraints are added to the rupture parameters. To improve the slip velocity function (SVF) modeling, an evolution of the k -2 source model is proposed, which consists to decompose the slip as a sum of sub-events by band of k. This model yields to SVF close to the solution proposed by Kostrov for a crack, while preserving the spectral characteristics of the radiated wave field, i.e. a w 2 model with spectral amplitudes at high frequency scaled to the coefficient of directivity C d . To better control the directivity effects, a composite source description is combined with a scaling law defining the extent of the nucleation area for each sub-event. The resulting model allows to reduce the apparent coefficient of directivity to a fraction of C d , as well as to reproduce the standard deviation of the new empirical attenuation relationships proposed for Japan. To make source models more realistic, a variable rupture velocity in agreement with the physics of the rupture must be considered. The followed approach that is based on an analytical relation between the fracture energy, the slip and the rupture velocity, leads to higher values of the peak ground acceleration in the vicinity of the fault. Finally, to better account for the interaction of the wave field with the geological medium, a semi-empirical methodology is developed combining a composite source model with empirical Green functions, and is applied to the Yamaguchi, M w 5.9 earthquake. The modeled synthetics reproduce satisfactorily well the observed main characteristics of ground motions. (author)

  12. A quantum kinematics for asymptotically flat gravity

    Science.gov (United States)

    Campiglia, Miguel; Varadarajan, Madhavan

    2015-07-01

    We construct a quantum kinematics for asymptotically flat gravity based on the Koslowski-Sahlmann (KS) representation. The KS representation is a generalization of the representation underlying loop quantum gravity (LQG) which supports, in addition to the usual LQG operators, the action of ‘background exponential operators’, which are connection dependent operators labelled by ‘background’ su(2) electric fields. KS states have, in addition to the LQG state label corresponding to one dimensional excitations of the triad, a label corresponding to a ‘background’ electric field that describes three dimensional excitations of the triad. Asymptotic behaviour in quantum theory is controlled through asymptotic conditions on the background electric fields that label the states and the background electric fields that label the operators. Asymptotic conditions on the triad are imposed as conditions on the background electric field state label while confining the LQG spin net graph labels to compact sets. We show that KS states can be realised as wave functions on a quantum configuration space of generalized connections and that the asymptotic behaviour of each such generalized connection is determined by that of the background electric fields which label the background exponential operators. Similar to the spatially compact case, the Gauss law and diffeomorphism constraints are then imposed through group averaging techniques to obtain a large sector of gauge invariant states. It is shown that this sector supports a unitary action of the group of asymptotic rotations and translations and that, as anticipated by Friedman and Sorkin, for appropriate spatial topology, this sector contains states that display fermionic behaviour under 2π rotations.

  13. A kinematic view of loop closure.

    Science.gov (United States)

    Coutsias, Evangelos A; Seok, Chaok; Jacobson, Matthew P; Dill, Ken A

    2004-03-01

    We consider the problem of loop closure, i.e., of finding the ensemble of possible backbone structures of a chain segment of a protein molecule that is geometrically consistent with preceding and following parts of the chain whose structures are given. We reduce this problem of determining the loop conformations of six torsions to finding the real roots of a 16th degree polynomial in one variable, based on the robotics literature on the kinematics of the equivalent rotator linkage in the most general case of oblique rotators. We provide a simple intuitive view and derivation of the polynomial for the case in which each of the three pair of torsional axes has a common point. Our method generalizes previous work on analytical loop closure in that the torsion angles need not be consecutive, and any rigid intervening segments are allowed between the free torsions. Our approach also allows for a small degree of flexibility in the bond angles and the peptide torsion angles; this substantially enlarges the space of solvable configurations as is demonstrated by an application of the method to the modeling of cyclic pentapeptides. We give further applications to two important problems. First, we show that this analytical loop closure algorithm can be efficiently combined with an existing loop-construction algorithm to sample loops longer than three residues. Second, we show that Monte Carlo minimization is made severalfold more efficient by employing the local moves generated by the loop closure algorithm, when applied to the global minimization of an eight-residue loop. Our loop closure algorithm is freely available at http://dillgroup. ucsf.edu/loop_closure/. Copyright 2004 Wiley Periodicals, Inc. J Comput Chem 25: 510-528, 2004

  14. P, C and T: Different Properties on the Kinematical Level

    Science.gov (United States)

    Dvoeglazov, Valeriy V.

    2018-04-01

    We study the discrete symmetries (P,C and T) on the kinematical level within the extended Poincaré Group. On the basis of the Silagadze research, we investigate the question of the definitions of the discrete symmetry operators both on the classical level, and in the secondary-quantization scheme. We study the physical contents within several bases: light-front formulation, helicity basis, angular momentum basis, and so on, on several practical examples. We analize problems in construction of the neutral particles in the the (1/2, 0) + (0, 1/2) representation, the (1, 0) + (0, 1) and the (1/2, 1/2) representations of the Lorentz Group. As well known, the photon has the quantum numbers 1‑, so the (1, 0) + (0, 1) representation of the Lorentz group is relevant to its description. We have ambiguities in the definitions of the corresponding operators P, C; T, which lead to different physical consequences. It appears that the answers are connected with the helicity basis properties, and commutations/anticommutations of the corresponding operators, P, C, T, and C 2, P 2, (CP)2 properties. This contribution is the review paper of my previous work [2, 3].

  15. Motivating Calculus-Based Kinematics Instruction with Super Mario Bros

    Science.gov (United States)

    Nordine, Jeffrey C.

    2011-09-01

    High-quality physics instruction is contextualized, motivates students to learn, and represents the discipline as a way of investigating the world rather than as a collection of facts and equations. Inquiry-oriented pedagogy, such as problem-based instruction, holds great promise for both teaching physics content and representing the process of doing real science.2 A challenge for physics teachers is to find instructional contexts that are meaningful, accessible, and motivating for students. Today's students are spending a growing fraction of their lives interacting with virtual environments, and these environments—physically realistic or not—can provide valuable contexts for physics explorations3-5 and lead to thoughtful discussions about decisions that programmers make when designing virtual environments. In this article, I describe a problem-based approach to calculus-based kinematics instruction that contextualizes students' learning within the Super Mario Bros. video game—a game that is more than 20 years old, but still remarkably popular with today's high school and college students.

  16. Kinematic Optimization of Robot Trajectories for Thermal Spray Coating Application

    Science.gov (United States)

    Deng, Sihao; Liang, Hong; Cai, Zhenhua; Liao, Hanlin; Montavon, Ghislain

    2014-12-01

    Industrial robots are widely used in the field of thermal spray nowadays. Due to their characteristics of high-accuracy and programmable flexibility, spraying on complex geometrical workpieces can be realized in the equipped spray room. However, in some cases, the robots cannot guarantee the process parameters defined by the robot movement, such as the scanning trajectory, spray angle, relative speed between the torch and the substrate, etc., which have distinct influences on heat and mass transfer during the generation of any thermally sprayed coatings. In this study, an investigation on the robot kinematics was proposed to find the rules of motion in a common case. The results showed that the motion behavior of each axis of robot permits to identify the motion problems in the trajectory. This approach allows to optimize the robot trajectory generation in a limited working envelop. It also minimizes the influence of robot performance to achieve a more constant relative scanning speed which is represented as a key parameter in thermal spraying.

  17. The Complex Kinematics of Galaxies in Hickson 67

    Science.gov (United States)

    Bettoni, D.; Buson, L. M.

    The kinematics of galaxies belonging to the Hickson compact group HCG67 are investigated. The latter consists of four galaxies, three of which (a, c, d) are embedded in a common envelope. The fourth galaxy (b) is a spiral that is detected both in radio and in IR wave-bands. Our observations show that the three galaxies in apparent interaction are probably caught during an ongoing merger process. Z Balcells, M., Morganti, R., Oosterloo, T., Peréz-Fournon, I. González Serrano, J. I. 1995, aap, 302, 665. Bertola, F., Bettoni, D., Rusconi, L., Sedmak, G. 1984, aj, 89, 356 Barnes, J. 1985, mnras, 215, 517 Hickson, P. 1982, apj, 255, 382 Hickson, P. 1993, Astrophys. Lett. Commun., 29, 1 Hickson, P., Menon, T. K., Palumbo, G. G. C., Persic, M. 1989, apj, 341,679 Leon, S., Combes, F., Menon, T. K. 1998, aap, 330, 37 Mamon, G. A. 1992, in "Physics of Nearby Galaxies: Nature or Nurture?", ed. T. X6. Thuan, C. Balkowski & Thran Thanh Van (12th Moriond Astrophysics Meeting)(Editions Frontiéres), p.367. Mendes de Oliveira, C., Hickson, P. 1991, apj, 380, 30 Mendes de Oliveira, C., Plana, H, Amram, P., Bolte, M., Boulesteix, J. 1998, apj, 507, 691 Menon, T. K. 1995, mnras, 274, 845 Rabaça, C. R., Sulentic, J. W. 1991, baas, 23, 1338 Zepf, S. E., Whitmore, B. C., Levison, H. F. 1991, apj, 383, 524

  18. Throwing velocity and kinematics in elite male water polo players.

    Science.gov (United States)

    Melchiorri, G; Padua, E; Padulo, J; D'Ottavio, S; Campagna, S; Bonifazi, M

    2011-12-01

    Fifty-three members of the Italian Men Water Polo Team were filmed using two synchronized cameras, while they were shooting a goal. Considering the differences in body mass, height, training strategies and the technical-tactical features of the players, the aims of this study were to employ video-analysis techniques in order to investigate selected kinematic parameters in water polo throwing, and to provide comprehensive quantitative information on the throwing movement in relation to the different team player positions. Video analysis was used to estimate the elbow angle at release, the shoulder angle at follow through, the back and head height at ball release, trunk rotation angle and ball velocity at release. Ball release velocities ranged from 21.0 to 29.8 m/s (average value 25.3±1.4 m/s), for field players. Goal keepers show the lowest team values (average 21.7±0.3 m/s). Similar to previous study results, ball release was typically reached just prior to the elbow approaching full extension (151.6±3.6°), and the follow through shoulder angle was 143±5.9°. No significant statistical difference was recorded between injured and non-injured athletes. No positive association was demonstrated between physical characteristics (body mass and height) and ball velocity.

  19. Does Focus of Attention Improve Snatch Lift Kinematics?

    Science.gov (United States)

    Schutts, Kyle S; Wu, Will F W; Vidal, Anthony D; Hiegel, Jamie; Becker, James

    2017-10-01

    Recent motor control literature has demonstrated that using verbal instructions to direct a performer's attention externally (i.e., toward the movement outcome) enhances motor skill performance. The purpose of this study was to investigate how an athlete's focus of attention impacts kinematic performance of the snatch. Using a counterbalanced within-participant design, 12 competitively trained athletes (8 male and 4 female athletes) performed 2 instructional blocks of 3 snatch repetitions at 80% of their most recent training 1 repetition maximum. Blocks of internal and external instructions were given to the athlete in a random fashion. Results showed that, when focusing internally, athletes significantly (p ≤ 0.05) increased elbow velocity relative to focusing externally, whereas the external instructions significantly increased horizontal barbell velocity, relative to internal instructions. Additionally, an internal focus resulted in significantly larger barbell-cervical-hip angles at maximum height of the barbell compared with an external focus, indicating that the athletes squatted under the barbell too soon. This information adds to the literature suggesting small changes in coaching instructions can impact performance significantly. It is recommended that coaches use instructions that direct an athlete's attention externally, toward the movement outcome, rather than the action itself.

  20. Kinematics of Nonlinearly Interacting MHD Instabilities in a Plasma

    International Nuclear Information System (INIS)

    Hansen, Alexander K.

    2000-01-01

    Plasmas play host to a wide variety of instabilities. For example, tearing instabilities use finite plasma resistivity to exploit the free energy provided by plasma currents parallel to the magnetic field to alter the magnetic topology of the plasma through a process known as reconnection. These instabilities frequently make themselves known in magnetic confinement experiments such as tokamaks and reversed field pinches (RFPs). In RFP plasmas, in fact, several tearing instabilities (modes) are simultaneously active, and are of large amplitude. Theory predicts that in addition to interacting linearly with magnetic perturbations from outside the plasma, such as field errors or as resistive wall, the modes in the RFP can interact nonlinearly with each other through a three-wave interaction. In the current work investigations of both the linear (external) and nonlinear contributions to the kinematics of the tearing modes in the Madison Symmetric Torus (MST) RFP are reported Theory predicts that tearing modes will respond only to magnetic perturbations that are spatially resonant with them, and was supported by experimental work done on tokamak devices. The results in this work verified that the theory is still applicable to the RFP, in spite of its more complicated magnetic mode structure, involving perturbations of a single poloidal mode number

  1. Generalizing a categorization of students’ interpretations of linear kinematics graphs

    Directory of Open Access Journals (Sweden)

    Laurens Bollen

    2016-02-01

    Full Text Available We have investigated whether and how a categorization of responses to questions on linear distance-time graphs, based on a study of Irish students enrolled in an algebra-based course, could be adopted and adapted to responses from students enrolled in calculus-based physics courses at universities in Flanders, Belgium (KU Leuven and the Basque Country, Spain (University of the Basque Country. We discuss how we adapted the categorization to accommodate a much more diverse student cohort and explain how the prior knowledge of students may account for many differences in the prevalence of approaches and success rates. Although calculus-based physics students make fewer mistakes than algebra-based physics students, they encounter similar difficulties that are often related to incorrectly dividing two coordinates. We verified that a qualitative understanding of kinematics is an important but not sufficient condition for students to determine a correct value for the speed. When comparing responses to questions on linear distance-time graphs with responses to isomorphic questions on linear water level versus time graphs, we observed that the context of a question influences the approach students use. Neither qualitative understanding nor an ability to find the slope of a context-free graph proved to be a reliable predictor for the approach students use when they determine the instantaneous speed.

  2. Generalizing a categorization of students' interpretations of linear kinematics graphs

    Science.gov (United States)

    Bollen, Laurens; De Cock, Mieke; Zuza, Kristina; Guisasola, Jenaro; van Kampen, Paul

    2016-06-01

    We have investigated whether and how a categorization of responses to questions on linear distance-time graphs, based on a study of Irish students enrolled in an algebra-based course, could be adopted and adapted to responses from students enrolled in calculus-based physics courses at universities in Flanders, Belgium (KU Leuven) and the Basque Country, Spain (University of the Basque Country). We discuss how we adapted the categorization to accommodate a much more diverse student cohort and explain how the prior knowledge of students may account for many differences in the prevalence of approaches and success rates. Although calculus-based physics students make fewer mistakes than algebra-based physics students, they encounter similar difficulties that are often related to incorrectly dividing two coordinates. We verified that a qualitative understanding of kinematics is an important but not sufficient condition for students to determine a correct value for the speed. When comparing responses to questions on linear distance-time graphs with responses to isomorphic questions on linear water level versus time graphs, we observed that the context of a question influences the approach students use. Neither qualitative understanding nor an ability to find the slope of a context-free graph proved to be a reliable predictor for the approach students use when they determine the instantaneous speed.

  3. Analysis of particle kinematics in spheronization via particle image velocimetry.

    Science.gov (United States)

    Koester, Martin; Thommes, Markus

    2013-02-01

    Spheronization is a wide spread technique in pellet production for many pharmaceutical applications. Pellets produced by spheronization are characterized by a particularly spherical shape and narrow size distribution. The particle kinematic during spheronization is currently not well-understood. Therefore, particle image velocimetry (PIV) was implemented in the spheronization process to visualize the particle movement and to identify flow patterns, in order to explain the influence of various process parameters. The spheronization process of a common formulation was recorded with a high-speed camera, and the images were processed using particle image velocimetry software. A crosscorrelation approach was chosen to determine the particle velocity at the surface of the pellet bulk. Formulation and process parameters were varied systematically, and their influence on the particle velocity was investigated. The particle stream shows a torus-like shape with a twisted rope-like motion. It is remarkable that the overall particle velocity is approximately 10-fold lower than the tip speed of the friction plate. The velocity of the particle stream can be correlated to the water content of the pellets and the load of the spheronizer, while the rotation speed was not relevant. In conclusion, PIV was successfully applied to the spheronization process, and new insights into the particle velocity were obtained. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Kinematic and Dynamic Analysis of a Cable-Climbing Robot

    Directory of Open Access Journals (Sweden)

    Xu Fengyu

    2015-07-01

    Full Text Available To inspect broken cables or a cracked protective layer on cable-stayed bridges, a cable-climbing robot has been proposed and designed. In this paper, the complex 3D obstacles that may be encountered on cables are theoretically described, in order to investigate the obstacle-climbing capability of the cable-climbing robot. A climbing model is then proposed and used to design the robot. In the climbing model, two driven wheels are independently supported with a spring. Kinematics and dynamics models are further derived for the obstacle-climbing capabilities of the driving and driven wheels of the robot. In addition, the robot's obstacle-climbing tracks and its obstacle-climbing performance are simulated. Payload and obstacle-climbing experiments were conducted on the climbing robot in the laboratory. Based on the results of the simulation and the experiments, we obtained the variation of the driving torque in obstacle climbing. The contribution of this paper is intended to provide a basis for the precise motion control of the robot.

  5. Numerical evaluation of tensor Feynman integrals in Euclidean kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Gluza, J.; Kajda [Silesia Univ., Katowice (Poland). Inst. of Physics; Riemann, T.; Yundin, V. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2010-10-15

    For the investigation of higher order Feynman integrals, potentially with tensor structure, it is highly desirable to have numerical methods and automated tools for dedicated, but sufficiently 'simple' numerical approaches. We elaborate two algorithms for this purpose which may be applied in the Euclidean kinematical region and in d=4-2{epsilon} dimensions. One method uses Mellin-Barnes representations for the Feynman parameter representation of multi-loop Feynman integrals with arbitrary tensor rank. Our Mathematica package AMBRE has been extended for that purpose, and together with the packages MB (M. Czakon) or MBresolve (A. V. Smirnov and V. A. Smirnov) one may perform automatically a numerical evaluation of planar tensor Feynman integrals. Alternatively, one may apply sector decomposition to planar and non-planar multi-loop {epsilon}-expanded Feynman integrals with arbitrary tensor rank. We automatized the preparations of Feynman integrals for an immediate application of the package sectordecomposition (C. Bogner and S. Weinzierl) so that one has to give only a proper definition of propagators and numerators. The efficiency of the two implementations, based on Mellin-Barnes representations and sector decompositions, is compared. The computational packages are publicly available. (orig.)

  6. Are undesirable contact kinematics minimized after kinematically aligned total knee arthroplasty? An intersurgeon analysis of consecutive patients.

    Science.gov (United States)

    Howell, Stephen M; Hodapp, Esther E; Vernace, Joseph V; Hull, Maury L; Meade, Thomas D

    2013-10-01

    Tibiofemoral contact kinematics or knee implant motions have a direct influence on patient function and implant longevity and should be evaluated for any new alignment technique such as kinematically aligned total knee arthroplasty (TKA). Edge loading of the tibial liner and external rotation (reverse of normal) and adduction of the tibial component on the femoral component are undesirable contact kinematics that should be minimized. Accordingly, this study determined whether the overall prevalence of undesirable contact kinematics during standing, mid kneeling near 90 degrees and full kneeling with kinematically aligned TKA are minimal and not different between groups of consecutive patients treated by different surgeons. Three surgeons were asked to perform cemented, kinematically aligned TKA with patient-specific guides in a consecutive series of patients with their preferred cruciate-retaining (CR) implant. In vivo tibiofemoral contact positions were obtained using a 3- to 2-dimensional image registration technique in 69 subjects (Vanguard CR-TKA N = 22, and Triathlon CR-TKA N = 47). Anterior or posterior edge loading of the tibial liner was not observed. The overall prevalence of external rotation of the tibial component on the femoral component of 6 % was low and not different between surgeons (n.s.). The overall prevalence of adduction of the tibial component on the femoral component of 4 % was low and not different between surgeons (n.s.). Kinematically aligned TKA minimized the undesirable contact kinematics of edge loading of the tibial liner, and external rotation and adduction of the tibial component on the femoral component during standing and kneeling, which suggests an optimistic prognosis for durable long-term function. III.

  7. Estimation of kinematic parameters in CALIFA galaxies: no-assumption on internal dynamics

    Science.gov (United States)

    García-Lorenzo, B.; Barrera-Ballesteros, J.; CALIFA Team

    2016-06-01

    We propose a simple approach to homogeneously estimate kinematic parameters of a broad variety of galaxies (elliptical, spirals, irregulars or interacting systems). This methodology avoids the use of any kinematical model or any assumption on internal dynamics. This simple but novel approach allows us to determine: the frequency of kinematic distortions, systemic velocity, kinematic center, and kinematic position angles which are directly measured from the two dimensional-distributions of radial velocities. We test our analysis tools using the CALIFA Survey

  8. Kinematic modeling of the Milky Way using the RAVE and GCS stellar surveys

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, S.; Bland-Hawthorn, J. [Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Binney, J. [Rudolf Peierls Center for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Freeman, K. C. [RSAA Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek, Canberra, ACT 72611 (Australia); Steinmetz, M.; Williams, M. E. K. [Leibniz Institut für Astrophysik Potsdam (AIP), An der Sterwarte 16, D-14482 Potsdam (Germany); Boeche, C.; Grebel, E. K. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, D-69120 Heidelberg (Germany); Bienaymé, O.; Siebert, A. [Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, F-67000 Strasbourg (France); Gibson, B. K. [Jeremiah Horrocks Institute for Astrophysics and Super-computing, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Gilmore, G. F.; Kordopatis, G. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Helmi, A. [Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen (Netherlands); Munari, U. [INAF-Astronomical Observatory of Padova, I-36012 Asiago (VI) (Italy); Navarro, J. F. [University of Victoria, P.O. Box 3055, Station CSC, Victoria, BC V8W 3P6 (Canada); Parker, Q. A.; Reid, W. A. [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Seabroke, G. M. [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking RH5 6NT (United Kingdom); Watson, F. [Australian Astronomical Observatory, P.O. Box 296, Epping, NSW 1710 (Australia); and others

    2014-09-20

    We investigate the kinematic parameters of the Milky Way disk using the Radial Velocity Experiment (RAVE) and Geneva-Copenhagen Survey (GCS) stellar surveys. We do this by fitting a kinematic model to the data and taking the selection function of the data into account. For stars in the GCS we use all phase-space coordinates, but for RAVE stars we use only (ℓ, b, v {sub los}). Using the Markov Chain Monte Carlo technique, we investigate the full posterior distributions of the parameters given the data. We investigate the age-velocity dispersion relation for the three kinematic components (σ {sub R}, σ{sub φ}, σ {sub z}), the radial dependence of the velocity dispersions, the solar peculiar motion (U {sub ☉}, V {sub ☉}, W {sub ☉}), the circular speed Θ{sub 0} at the Sun, and the fall of mean azimuthal motion with height above the midplane. We confirm that the Besançon-style Gaussian model accurately fits the GCS data but fails to match the details of the more spatially extended RAVE survey. In particular, the Shu distribution function (DF) handles noncircular orbits more accurately and provides a better fit to the kinematic data. The Gaussian DF not only fits the data poorly but systematically underestimates the fall of velocity dispersion with radius. The radial scale length of the velocity dispersion profile of the thick disk was found to be smaller than that of the thin disk. We find that correlations exist between a number of parameters, which highlights the importance of doing joint fits. The large size of the RAVE survey allows us to get precise values for most parameters. However, large systematic uncertainties remain, especially in V {sub ☉} and Θ{sub 0}. We find that, for an extended sample of stars, Θ{sub 0} is underestimated by as much as 10% if the vertical dependence of the mean azimuthal motion is neglected. Using a simple model for vertical dependence of kinematics, we find that it is possible to match the Sgr A* proper motion without

  9. KINEMATIC CLASSIFICATIONS OF LOCAL INTERACTING GALAXIES: IMPLICATIONS FOR THE MERGER/DISK CLASSIFICATIONS AT HIGH-z

    International Nuclear Information System (INIS)

    Hung, Chao-Ling; Larson, Kirsten L.; Sanders, D. B.; Rich, Jeffrey A.; Yuan, Tiantian; Kewley, Lisa J.; Casey, Caitlin M.; Smith, Howard A.; Hayward, Christopher C.

    2015-01-01

    The classification of galaxy mergers and isolated disks is key for understanding the relative importance of galaxy interactions and secular evolution during the assembly of galaxies. Galaxy kinematics as traced by emission lines have been used to suggest the existence of a significant population of high-z star-forming galaxies consistent with isolated rotating disks. However, recent studies have cautioned that post-coalescence mergers may also display disk-like kinematics. To further investigate the robustness of merger/disk classifications based on kinematic properties, we carry out a systematic classification of 24 local (U)LIRGs spanning a range of morphologies: from isolated spiral galaxies, ongoing interacting systems, to fully merged remnants. We artificially redshift the Wide Field Spectrograph observations of these local (U)LIRGs to z = 1.5 to make a realistic comparison with observations at high-z, and also to ensure that all galaxies have the same spatial sampling of ∼900 pc. Using both kinemetry-based and visual classifications, we find that the reliability of kinematic classification shows a strong trend with the interaction stage of galaxies. Mergers with two nuclei and tidal tails have the most distinct kinematics compared to isolated disks, whereas a significant population of the interacting disks and merger remnants are indistinguishable from isolated disks. The high fraction of mergers displaying disk-like kinematics reflects the complexity of the dynamics during galaxy interactions. Additional merger indicators such as morphological properties traced by stars or molecular gas are required to further constrain the merger/disk classifications at high-z

  10. Kinematic and Electromyographic Activity Changes during Back Squat with Submaximal and Maximal Loading

    Directory of Open Access Journals (Sweden)

    Hasan U. Yavuz

    2017-01-01

    Full Text Available The aim of this study was to investigate the possible kinematic and muscular activity changes with maximal loading during squat maneuver. Fourteen healthy male individuals, who were experienced at performing squats, participated in this study. Each subject performed squats with 80%, 90%, and 100% of the previously established 1 repetition maximum (1RM. Electromyographic (EMG activities were measured for the vastus lateralis, vastus medialis, rectus femoris, semitendinosus, biceps femoris, gluteus maximus, and erector spinae by using an 8-channel dual-mode portable EMG and physiological signal data acquisition system (Myomonitor IV, Delsys Inc., Boston, MA, USA. Kinematical data were analyzed by using saSuite 2D kinematical analysis program. Data were analyzed with repeated measures analysis of variance (p<0.05. Overall muscle activities increased with increasing loads, but significant increases were seen only for vastus medialis and gluteus maximus during 90% and 100% of 1RM compared to 80% while there was no significant difference between 90% and 100% for any muscle. The movement pattern in the hip joint changed with an increase in forward lean during maximal loading. Results may suggest that maximal loading during squat may not be necessary for focusing on knee extensor improvement and may increase the lumbar injury risk.

  11. A case study using kinematic quantities derived from a triangle of VHF Doppler wind profilers

    Science.gov (United States)

    Carlson, Catherine A.; Forbes, Gregory S.

    1989-01-01

    Horizontal divergence, relative vorticity, kinematic vertical velocity, and geostrophic and ageostrophic winds are computed from Colorado profiler network data to investigate an upslope snowstorm in northeastern Colorado. Horizontal divergence and relative vorticity are computed using the Gauss and Stokes theorems, respectively. Kinematic vertical velocities are obtained from the surface to 9 km by vertically integrating the continuity equation. The geostrophic and ageostrophic winds are computed by applying a finite differencing technique to evaluate the derivatives in the horizontal equations of motion. Comparison of the synoptic-scale data with the profiler network data reveals that the two datasets are generally consistent. Also, the profiler-derived quantities exhibit coherent vertical and temporal patterns consistent with conceptual and theoretical flow fields of various meteorological phenomena. It is suggested that the profiler-derived quantities are of potential use to weather forecasters in that they enable the dynamic and kinematic interpretation of weather system structure to be made and thus have nowcasting and short-term forecasting value.

  12. Gender differences in gait kinematics in runners with iliotibial band syndrome.

    Science.gov (United States)

    Phinyomark, A; Osis, S; Hettinga, B A; Leigh, R; Ferber, R

    2015-12-01

    Atypical running gait biomechanics are considered a primary factor in the etiology of iliotibial band syndrome (ITBS). However, a general consensus on the underpinning kinematic differences between runners with and without ITBS is yet to be reached. This lack of consensus may be due in part to three issues: gender differences in gait mechanics, the preselection of discrete biomechanical variables, and/or relatively small sample sizes. Therefore, this study was designed to address two purposes: (a) examining differences in gait kinematics for male and female runners experiencing ITBS at the time of testing and (b) assessing differences in gait kinematics between healthy gender- and age-matched runners as compared with their ITBS counterparts using waveform analysis. Ninety-six runners participated in this study: 48 ITBS and 48 healthy runners. The results show that female ITBS runners exhibited significantly greater hip external rotation compared with male ITBS and female healthy runners. On the contrary, male ITBS runners exhibited significantly greater ankle internal rotation compared with healthy males. These results suggest that care should be taken to account for gender when investigating the biomechanical etiology of ITBS. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Aquatic wing flapping at low Reynolds numbers: swimming kinematics of the Antarctic pteropod, Clione antarctica.

    Science.gov (United States)

    Borrell, Brendan J; Goldbogen, Jeremy A; Dudley, Robert

    2005-08-01

    We studied swimming kinematics of the Antarctic pteropod, Clione antarctica, to investigate how propulsive forces are generated by flexible oscillating appendages operating at low Reynolds numbers (10stroke of flapping consisted of distinct power and recovery phases, which were of approximately equal duration in both the upstroke and the downstroke. As pteropods ascended, the body traced a sawtooth path when viewed laterally. The magnitude of these oscillations decreased with body mass, and larger animals (operating at Re>25) exhibited gliding during the recovery phase of each half-stroke. Maximum translational and rotational accelerations of the body occurred at the initiation of each power phase, suggesting that rotational circulation, the acceleration reaction, and wake recapture may all potentially contribute to vertical force production. Individual contributions of these mechanisms cannot, however, be assessed from these kinematic data alone. During recovery phases of each half-stroke, C. antarctica minimized adverse drag forces by orienting the wings parallel to flow and by moving them along the body surface, possibly taking advantage of boundary layer effects. Vertical force production was altered through changes in the hydrodynamic angle of attack of the wing that augmented drag during the power phase of each half-stroke. At higher translational velocities of the body, the inclination of the power phase also became more nearly vertical. These results indicate that, in addition to serotonin-mediated modulation of wingbeat frequency reported previously in Clione, geometric alteration of wingbeat kinematics offers a precise means of controlling swimming forces.

  14. Integrated kinematics-kinetics-plantar pressure data analysis: a useful tool for characterizing diabetic foot biomechanics.

    Science.gov (United States)

    Sawacha, Zimi; Guarneri, Gabriella; Cristoferi, Giuseppe; Guiotto, Annamaria; Avogaro, Angelo; Cobelli, Claudio

    2012-05-01

    The fundamental cause of lower-extremity complications in diabetes is chronic hyperglycemia leading to diabetic foot ulcer pathology. While the relationship between abnormal plantar pressure distribution and plantar ulcers has been widely investigated, little is known about the role of shear stress. Moreover, the mutual relationship among plantar pressure, shear stress, and abnormal kinematics in the etiology of diabetic foot has not been established. This lack of knowledge is determined by the lack of commercially available instruments which allow such a complex analysis. This study aims to develop a method for the simultaneous assessment of kinematics, kinetics, and plantar pressure on foot subareas of diabetic subjects by means of combining three commercial systems. Data were collected during gait on 24 patients (12 controls and 12 diabetic neuropathics) with a motion capture system synchronized with two force plates and two baropodometric systems. A four segment three-dimensional foot kinematics model was adopted for the subsegment angles estimation together with a three segment model for the plantar sub-area definition during gait. The neuropathic group exhibited significantly excessive plantar pressure, ground reaction forces on each direction, and a reduced loading surface on the midfoot subsegment (pfoot ulcerations, and help planning prevention programs. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Distinct hip and rearfoot kinematics in female runners with a history of tibial stress fracture.

    Science.gov (United States)

    Milner, Clare E; Hamill, Joseph; Davis, Irene S

    2010-02-01

    Cross-sectional controlled laboratory study. To investigate the kinematics of the hip, knee, and rearfoot in the frontal and transverse planes in female distance runners with a history of tibial stress fracture. Tibial stress fractures are a common overuse injury in runners, accounting for up to half of all stress fractures. Abnormal kinematics of the lower extremity may contribute to abnormal musculoskeletal load distributions, leading to an increased risk of stress fractures. Thirty female runners with a history of tibial stress fracture were compared to 30 age-matched and weekly-running-distance-matched control subjects with no previous lower extremity bony injuries. Kinematic and kinetic data were collected using a motion capture system and a force platform, respectively, as subjects ran in the laboratory. Selected variables of interest were compared between the groups using a multivariate analysis of variance (MANOVA). Peak hip adduction and peak rearfoot eversion angles were greater in the stress fracture group compared to the control group. Peak knee adduction and knee internal rotation angles and all joint angles at impact peak were similar between the groups. Runners with a previous tibial stress fracture exhibited greater peak hip adduction and rearfoot eversion angles during the stance phase of running compared to healthy controls. A consequence of these mechanics may be altered load distribution within the lower extremity, predisposing individuals to stress fracture.

  16. COMPARATIVE KINEMATIC MEASURES OF TREADMILL RUNNING WITH OR WITHOUT BODY WEIGHT SUPPORT IN RUNNERS

    Directory of Open Access Journals (Sweden)

    Duane Millslagle

    2005-12-01

    Full Text Available Treadmill walking and running using a supportive harness has been used as a training method to rehabilitate injured patients' walking or running gait. Comparison of full weight support (FWS and body weight support (BWS kinematic measures in competitive runners has received little attention. The purpose of this study was to compare selected FWS to BWS kinematic measures in healthy competitive runners. Ten male runners (age = 21.4 ± 1.5 years with a training regimen averaging 64 km per week at 3.8 m·s-1 participated. All participants ran three 3-minute trials. The randomized trial conditions were: FWS, 20% BWS, and 40% BWS. All conditions were videotaped with 2 cameras and a 21-point, 3-D model was generated for analysis. From the position-time data, cycle length (CL, cycle frequency (CF, time of contact (TC, hip-, knee-, ankle- range of motion in degrees (H-ROM, K-ROM, and A-ROM, respectively, and vertical displacement of the center of mass (COM were derived and compared. With increasing support conditions, cycle length increased. Cycle frequency, hip and ankle angle ranges, and COM vertical displacement decreased (p 0.05. BWS running produced significant changes in selected kinematic measures. These changes may provide insight into runners' behavior when using BWS in training or recovery from competition. Additional investigation of BWS training affect with competitive runners would be recommended

  17. Strategies for probing nonminimal dark sectors at colliders: The interplay between cuts and kinematic distributions

    Science.gov (United States)

    Dienes, Keith R.; Su, Shufang; Thomas, Brooks

    2015-03-01

    In this paper, we examine the strategies and prospects for distinguishing between traditional dark-matter models and models with nonminimal dark sectors—including models of Dynamical Dark Matter—at hadron colliders. For concreteness, we focus on events with two hadronic jets and large missing transverse energy at the Large Hadron Collider (LHC). As we discuss, simple "bump-hunting" searches are not sufficient; probing nonminimal dark sectors typically requires an analysis of the actual shapes of the distributions of relevant kinematic variables. We therefore begin by identifying those kinematic variables whose distributions are particularly suited to this task. However, as we demonstrate, this then leads to a number of additional subtleties, since cuts imposed on the data for the purpose of background reduction can at the same time have the unintended consequence of distorting these distributions in unexpected ways, thereby obscuring signals of new physics. We therefore proceed to study the correlations between several of the most popular relevant kinematic variables currently on the market, and investigate how imposing cuts on one or more of these variables can impact the distributions of others. Finally, we combine our results in order to assess the prospects for distinguishing nonminimal dark sectors in this channel at the upgraded LHC.

  18. Kinematic Analysis of a Posterior-stabilized Knee Prosthesis

    Science.gov (United States)

    Zhao, Zhi-Xin; Wen, Liang; Qu, Tie-Bing; Hou, Li-Li; Xiang, Dong; Bin, Jia

    2015-01-01

    Background: The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Methods: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0–135° flexion. Results: Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, “rollback” compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. Conclusions: There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis. PMID:25591565

  19. Kinematic cross-correlation induces sensory integration across separate objects.

    Science.gov (United States)

    Debats, Nienke B; Ernst, Marc O; Heuer, Herbert

    2017-12-01

    In a basic cursor-control task, the perceived positions of the hand and the cursor are biased towards each other. We recently found that this phenomenon conforms to the reliability-based weighting mechanism of optimal multisensory integration. This indicates that optimal integration is not restricted to sensory signals originating from a single source, as is the prevailing view, but that it also applies to separate objects that are connected by a kinematic relation (i.e. hand and cursor). In the current study, we examined which aspects of the kinematic relation are crucial for eliciting the sensory integration: (i) the cross-correlation between kinematic variables of the hand and cursor trajectories, and/or (ii) an internal model of the hand-cursor kinematic transformation. Participants made out-and-back movements from the centre of a semicircular workspace to its boundary, after which they judged the position where either their hand or the cursor hit the boundary. We analysed the position biases and found that the integration was strong in a condition with high kinematic correlations (a straight hand trajectory was mapped to a straight cursor trajectory), that it was significantly reduced for reduced kinematic correlations (a straight hand trajectory was transformed into a curved cursor trajectory) and that it was not affected by the inability to acquire an internal model of the kinematic transformation (i.e. by the trial-to-trial variability of the cursor curvature). These findings support the idea that correlations play a crucial role in multisensory integration irrespective of the number of sensory sources involved. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  20. Kinematic analysis of a posterior-stabilized knee prosthesis.

    Science.gov (United States)

    Zhao, Zhi-Xin; Wen, Liang; Qu, Tie-Bing; Hou, Li-Li; Xiang, Dong; Bin, Jia

    2015-01-20

    The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion. Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, "rollback" compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis.

  1. Kinematic Analysis of a Posterior-stabilized Knee Prosthesis

    Directory of Open Access Journals (Sweden)

    Zhi-Xin Zhao

    2015-01-01

    Full Text Available Background: The goal of total knee arthroplasty (TKA is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Methods: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion. Results: Both the output data trends and the measured values derived from the normal knee′s kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, "rollback" compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. Conclusions: There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis.

  2. Kinematic Hardening: Characterization, Modeling and Impact on Springback Prediction

    International Nuclear Information System (INIS)

    Alves, J. L.; Bouvier, S.; Jomaa, M.; Billardon, R.; Oliveira, M. C.; Menezes, L. F.

    2007-01-01

    The constitutive modeling of the materials' mechanical behavior, usually carried out using a phenomenological constitutive model, i.e., a yield criterion associated to the isotropic and kinematic hardening laws, is of paramount importance in the FEM simulation of the sheet metal forming processes, as well as in the springback prediction. Among others, the kinematic behavior of the yield surface plays an essential role, since it is indispensable to describe the Bauschinger effect, i.e., the materials' answer to the multiple tension-compression cycles to which material points are submitted during the forming process. Several laws are usually used to model and describe the kinematic hardening, namely: a) the Prager's law, which describes a linear evolution of the kinematic hardening with the plastic strain rate tensor b) the Frederick-Armstrong non-linear kinematic hardening, basically a non-linear law with saturation; and c) a more advanced physically-based law, similar to the previous one but sensitive to the strain path changes. In the present paper a mixed kinematic hardening law (linear + non-linear behavior) is proposed and its implementation into a static fully-implicit FE code is described. The material parameters identification for sheet metals using different strategies, and the classical Bauschinger loading tests (i.e. in-plane forward and reverse monotonic loading), are addressed, and their impact on springback prediction evaluated. Some numerical results concerning the springback prediction of the Numisheet'05 Benchmark no. 3 are briefly presented to emphasize the importance of a correct modeling and identification of the kinematic hardening behavior

  3. Does Shoe Collar Height Influence Ankle Joint Kinematics and Kinetics in Sagittal Plane Maneuvers?

    Science.gov (United States)

    Yang, Yang; Fang, Ying; Zhang, Xini; He, Junliang; Fu, Weijie

    2017-01-01

    The Objective of the study is to investigate the effects of basketball shoes with different collar heights on ankle kinematics and kinetics and athletic performance in different sagittal plane maneuvers. Twelve participants who wore high-top and low-top basketball shoes (hereafter, HS and LS, respectively) performed a weight-bearing dorsiflexion (WB-DF) maneuver, drop jumps (DJs), and lay-up jumps (LJs). Their sagittal plane kinematics and ground reaction forces were recorded using the Vicon motion capture system and Kistler force plates simultaneously. Moreover, ankle dorsiflexion and plantarflexion angles, moment, power, stiffness, and jump height were calculated. In the WB-DF test, the peak ankle dorsiflexion angle (p = 0.041) was significantly smaller in HS than in LS. Additionally, the peak ankle plantarflexion moment (p = 0.028) and power (p = 0.022) were significantly lower in HS than in LS during LJs but not during DJs. In both jumping maneuvers, no significant differences were found in the jump height or ankle kinematics between the two shoe types. According to the WB-DF test, increasing shoe collar height can effectively reduce the ankle range of motion in the sagittal plane. Although the HS did not restrict the flexion–extension performance of the ankle joint during two jumping maneuvers, an increased shoe collar height can reduce peak ankle plantarflexion moment and peak power during the push-off phase in LJs. Therefore, a higher shoe collar height should be used to circumvent effects on the partial kinetics of the ankle joint in the sagittal plane. Key points An increased shoe collar height effectively reduced ankle joint ROM in the sagittal plane in weight-bearing dorsiflexion maneuver. Shoe collar height did not affect sagittal plane ankle kinematics and had no effect on performance during realistic jumping. Shoe collar height can affect the ankle plantarflexion torque and peak power during the push-off phase in lay-up jump. PMID:29238255

  4. Knee Motion Generation Method for Transfemoral Prosthesis Based on Kinematic Synergy and Inertial Motion.

    Science.gov (United States)

    Sano, Hiroshi; Wada, Takahiro

    2017-12-01

    Previous research has shown that the effective use of inertial motion (i.e., less or no torque input at the knee joint) plays an important role in achieving a smooth gait of transfemoral prostheses in the swing phase. In our previous research, a method for generating a timed knee trajectory close to able-bodied individuals, which leads to sufficient clearance between the foot and the floor and the knee extension, was proposed using the inertial motion. Limb motions are known to correlate with each other during walking. This phenomenon is called kinematic synergy. In this paper, we measure gaits in level walking of able-bodied individuals with a wide range of walking velocities. We show that this kinematic synergy also exists between the motions of the intact limbs and those of the knee as determined by the inertial motion technique. We then propose a new method for generating the motion of the knee joint using its inertial motion close to the able-bodied individuals in mid-swing based on its kinematic synergy, such that the method can adapt to the changes in the motion velocity. The numerical simulation results show that the proposed method achieves prosthetic walking similar to that of able-bodied individuals with a wide range of constant walking velocities and termination of walking from steady-state walking. Further investigations have found that a kinematic synergy also exists at the start of walking. Overall, our method successfully achieves knee motion generation from the initiation of walking through steady-state walking with different velocities until termination of walking.

  5. Three-Dimensional Scapular Kinematics in Patients with Reverse Total Shoulder Arthroplasty during Arm Motion.

    Science.gov (United States)

    Lee, Kwang Won; Kim, Yong In; Kim, Ha Yong; Yang, Dae Suk; Lee, Gyu Sang; Choy, Won Sik

    2016-09-01

    There have been few reports on altered kinematics of the shoulder after reverse total shoulder arthroplasty (RTSA). We investigated differences in 3-dimensional (3D) scapular motions assessed using an optical tracking system between RTSA treated shoulders and asymptomatic contralateral shoulders during arm motion. Thirteen patients who underwent RTSA were assessed for active arm elevation in 2 distinct elevation planes (sagittal plane flexion and scapular plane abduction). Their mean age was 72 years (range, 69 to 79 years) and the mean follow-up was 24.4 months (range, 13 to 48 months). The dominant side was the right side in all the 13 patients, and it was also the side treated with RTSA. Scapular kinematics was recorded with an optical tracking system. The scapular kinematics and the scapulohumeral rhythm (SHR) of the RTSA shoulders and asymptomatic contralateral shoulders were recorded and analyzed during arm elevation. There were no significant differences in internal/external rotation and anterior/posterior tilting of the scapula between shoulders during arm motion (p > 0.05). However, upward rotation of the scapula differed significantly during arm motion (p = 0.035 for sagittal plane flexion; p = 0.046 for scapular plane abduction). There were significant differences in the SHR between the two shoulders (p = 0.016 for sagittal plane flexion; p = 0.021 for scapular plane abduction). The shoulder kinematics after RTSA showed significant differences from the contralateral asymptomatic shoulders. Increased upward rotation and decreased SHR after RTSA indicate that RTSA shoulders use more scapulothoracic motion and less glenohumeral motion to elevate the arm.

  6. Neck Kinematics and Electromyography While Wearing Head Supported Mass During Running.

    Science.gov (United States)

    Hanks, Matthew M; Sefton, JoEllen M; Oliver, Gretchen D

    2018-01-01

    Advanced combat helmets (ACH) coupled with night-vision goggles (NVG) are required for tactical athletes during training and service. Head and neck injuries due to head supported mass (HSM) are a common occurrence in military personnel. The current study aimed to investigate the effects of HSM on neck muscle fatigue that may lead to chronic stress and injury of the head and neck. Subjects wore an ACH and were affixed with electromagnetic sensors to obtain kinematic data, as well as EMG electrodes to obtain muscle activations of bilateral sternocleidomastoid, upper trapezius, and paraspinal muscles while running on a treadmill. Subjects performed a 2-min warmup at a walking pace, a 5-min warmup jog, running at a pace equal to 90% maximum heart rate until absolute fatigue, and lastly a 2-min cooldown at a walking pace. Kinematic and EMG data were collected over each 2-min interval. Days later, the same subjects wore the same ACH in addition to the NVG and performed the same protocol as the first session. This study showed significant differences in muscle activation of the right upper trapezius [F(1,31) = 10.100] and both sternocleidomastoid [F(1,31) = 12.280] muscles from pre-fatigue to absolute fatigue. There were no significant differences noted in the kinematic variables. This study suggests that HSM can fatigue bilateral neck flexors and rotators, as well as fatigue the neck extensors and rotators on the contralateral side of the mounted NVG.Hanks MM, Sefton JM, Oliver GD. Neck kinematics and electromyography while wearing head supported mass during running. Aerosp Med Hum Perform. 2018; 89(1):9-13.

  7. The SAMI Galaxy Survey: gas content and interaction as the drivers of kinematic asymmetry

    Science.gov (United States)

    Bloom, J. V.; Croom, S. M.; Bryant, J. J.; Schaefer, A. L.; Bland-Hawthorn, J.; Brough, S.; Callingham, J.; Cortese, L.; Federrath, C.; Scott, N.; van de Sande, J.; D'Eugenio, F.; Sweet, S.; Tonini, C.; Allen, J. T.; Goodwin, M.; Green, A. W.; Konstantopoulos, I. S.; Lawrence, J.; Lorente, N.; Medling, A. M.; Owers, M. S.; Richards, S. N.; Sharp, R.

    2018-05-01

    In order to determine the causes of kinematic asymmetry in the Hα gas in the SAMI (Sydney-AAO Multi-object IFS) Galaxy Survey sample, we investigate the comparative influences of environment and intrinsic properties of galaxies on perturbation. We use spatially resolved Hα velocity fields from the SAMI Galaxy Survey to quantify kinematic asymmetry (\\overline{v_asym}) in nearby galaxies and environmental and stellar mass data from the Galaxy And Mass Assembly survey. We find that local environment, measured as distance to nearest neighbour, is inversely correlated with kinematic asymmetry for galaxies with log (M*/M⊙) > 10.0, but there is no significant correlation for galaxies with log (M*/M⊙) < 10.0. Moreover, low-mass galaxies [log (M*/M⊙) < 9.0] have greater kinematic asymmetry at all separations, suggesting a different physical source of asymmetry is important in low-mass galaxies. We propose that secular effects derived from gas fraction and gas mass may be the primary causes of asymmetry in low-mass galaxies. High gas fraction is linked to high σ _m/V (where σm is Hα velocity dispersion and V the rotation velocity), which is strongly correlated with \\overline{v_asym}, and galaxies with log (M*/M⊙) < 9.0 have offset \\overline{σ _m/V} from the rest of the sample. Further, asymmetry as a fraction of dispersion decreases for galaxies with log (M*/M⊙) < 9.0. Gas mass and asymmetry are also inversely correlated in our sample. We propose that low gas masses in dwarf galaxies may lead to asymmetric distribution of gas clouds, leading to increased relative turbulence.

  8. Scapular kinematics during manual wheelchair propulsion in able-bodied participants.

    Science.gov (United States)

    Bekker, Michel J; Vegter, Riemer J K; van der Scheer, Jan W; Hartog, Johanneke; de Groot, Sonja; de Vries, Wiebe; Arnet, Ursina; van der Woude, Lucas H V; Veeger, Dirkjan H E J

    2018-05-01

    Altered scapular kinematics have been associated with shoulder pain and functional limitations. To understand kinematics in persons with spinal cord injury during manual handrim wheelchair propulsion, a description of normal scapular behaviour in able-bodied persons during this specific task is a prerequisite for accurate interpretation. The primary aim of this study is to describe scapular kinematics in able-bodied persons during manual wheelchair propulsion. Sixteen able-bodied, novice wheelchair users without shoulder complaints participated in the study. Kinematic and kinetic data were collected during a standardized pose in the anatomic posture, frontal-plane arm elevation and low-intensity steady-state handrim wheelchair propulsion and upper-body Euler angles were calculated. Scapulothoracic joint orientations in a static position were 36.7° (SD 5.4°), 6.4° (SD 9.1°) and 9.1° (SD 5.7°) for respectively protraction, lateral rotation and anterior tilt. At 80° of arm elevation in the frontal plane, the respective values of 33.4° (SD 8.0°), 23.9° (SD 5.4°) and 4.1° (SD 11.3°) were found. During the push phase of manual wheelchair propulsion, the mean scapular rotations were respectively 32.7° (SD 7.1°), 7.1° (SD 9.2°) and 9.8° (SD 8.3°). The orientation of the scapula in a static pose, during arm elevation and in manual wheelchair propulsion in able-bodied participants showed similar patterns to a previous study in persons with para- and tetraplegia. These values provide a reference for the investigation of the scapular movement pattern in wheelchair-dependent persons and its relation to shoulder complex abnormalities. Copyright © 2018. Published by Elsevier Ltd.

  9. Kinematic synthesis of adjustable robotic mechanisms

    Science.gov (United States)

    Chuenchom, Thatchai

    1993-01-01

    Conventional hard automation, such as a linkage-based or a cam-driven system, provides high speed capability and repeatability but not the flexibility required in many industrial applications. The conventional mechanisms, that are typically single-degree-of-freedom systems, are being increasingly replaced by multi-degree-of-freedom multi-actuators driven by logic controllers. Although this new trend in sophistication provides greatly enhanced flexibility, there are many instances where the flexibility needs are exaggerated and the associated complexity is unnecessary. Traditional mechanism-based hard automation, on the other hand, neither can fulfill multi-task requirements nor are cost-effective mainly due to lack of methods and tools to design-in flexibility. This dissertation attempts to bridge this technological gap by developing Adjustable Robotic Mechanisms (ARM's) or 'programmable mechanisms' as a middle ground between high speed hard automation and expensive serial jointed-arm robots. This research introduces the concept of adjustable robotic mechanisms towards cost-effective manufacturing automation. A generalized analytical synthesis technique has been developed to support the computational design of ARM's that lays the theoretical foundation for synthesis of adjustable mechanisms. The synthesis method developed in this dissertation, called generalized adjustable dyad and triad synthesis, advances the well-known Burmester theory in kinematics to a new level. While this method provides planar solutions, a novel patented scheme is utilized for converting prescribed three-dimensional motion specifications into sets of planar projections. This provides an analytical and a computational tool for designing adjustable mechanisms that satisfy multiple sets of three-dimensional motion specifications. Several design issues were addressed, including adjustable parameter identification, branching defect, and mechanical errors. An efficient mathematical scheme for

  10. Kinematics and Kinetics of Squat and Deadlift Exercises with Varying Stance Widths

    Science.gov (United States)

    DeWitt, John K.; Fincke, Renita S.; Logan, Rachel L.

    2011-01-01

    The primary motion of squat and deadlift exercise involves flexion and extension of the hips, knees, and ankles, but each exercise can be performed with variations in stance width. These variations may result in differing kinematics and ground reaction forces (GRF), which may in turn affect joint loading. PURPOSE: The purpose of this investigation was to compare ankle, knee, and hip kinematics and kinetics of normal squat (NS), wide-stance squat (WS), normal deadlift (ND), and sumo deadlift (SD). We hypothesized that hip joint kinematics and work at each joint would differ between exercise variations. METHODS: Six subjects (3 m/3 f; 70.0 plus or minus 13.7 kg; 168 plus or minus 9.9 cm) performed each lift in normal gravity on the ground-based version of the Advanced Resistive Exercise Device (ARED) used on the International Space Station. The ARED provided resistance with a combination vacuum tube/flywheel mechanism designed to replicate the gravitational and inertial forces of free weights. Subjects completed each lift with their 10-repetition maximum load. Kinematic data were collected at 250 Hz by a 12-camera motion-capture system (Smart-D, BTS Bioengineering, Milan, Italy), and GRF data were collected at 1000 Hz with independent force platforms for each leg (Model 9261, Kistler Instruments AG, Winterhur, Switzerland). All data were captured simultaneously on a single workstation. The right leg of a single lift for each motion was analyzed. Modeling software (OpenSim 2.2.0, Simbios, Palo Alto, CA) determined joint kinematics and net positive and negative work at each lower extremity joint. Total work was found as the sum of work across all joints and was normalized by system mass. Effect sizes and their 95% confidence intervals were computed between conditions. RESULTS: Peak GRF were similar for each lift. There were no differences between conditions in hip flexion range of motion (ROM). For hip adduction ROM, there were no differences between the NS, WS, and SD

  11. Kinematic seismic response of piles in layered soil profile

    International Nuclear Information System (INIS)

    Ahmad, I.; Khan, A.N.

    2006-01-01

    This paper is aimed at highlighting the importance of Kinematic Seismic Response of Piles, a phenomenon often ignored in dynamic analysis. A case study is presented where the end bearing pile is embedded in two layer soil system of highly contrasting stiffnesses; a typical case where kinematic loading plays important role. The pile soil system is modeled as continuous system and as discrete parameter system; both are based on BDWF (Beam on Dynamic Winkler Foundation) formulation. For discrete parameter system, a finite element software SAP2000 is used and the modeling technique of kinematic interaction in finite element software is discussed. For pile soil system modeled as continuous system, a general MATLAB code is developed capable of performing elastic site response analysis in two layer soil system, solving differential equation governing kinematic interaction, and giving as output the maximum ground displacement, maximum pile displacement, rotation, moment and shear distribution along pile length. The paper concludes that kinematic seismic actions must be evaluated particularly at the interface of soil layers of significantly differing soil stiffnesses. (author)

  12. ISS Squat and Deadlift Kinematics on the Advanced Resistive Exercise Device

    Science.gov (United States)

    Newby, N.; Caldwell, E.; Sibonga, J.; Ploutz-Snyder, L.

    2014-01-01

    Visual assessment of exercise form on the Advanced Resistive Exercise Device (ARED) on orbit is difficult due to the motion of the entire device on its Vibration Isolation System (VIS). The VIS allows for two degrees of device translational motion, and one degree of rotational motion. In order to minimize the forces that the VIS must damp in these planes of motion, the floor of the ARED moves as well during exercise to reduce changes in the center of mass of the system. To help trainers and other exercise personnel better assess squat and deadlift form a tool was developed that removes the VIS motion and creates a stick figure video of the exerciser. Another goal of the study was to determine whether any useful kinematic information could be obtained from just a single camera. Finally, the use of these data may aid in the interpretation of QCT hip structure data in response to ARED exercises performed in-flight. After obtaining informed consent, four International Space Station (ISS) crewmembers participated in this investigation. Exercise was videotaped using a single camera positioned to view the side of the crewmember during exercise on the ARED. One crewmember wore reflective tape on the toe, heel, ankle, knee, hip, and shoulder joints. This technique was not available for the other three crewmembers, so joint locations were assessed and digitized frame-by-frame by lab personnel. A custom Matlab program was used to assign two-dimensional coordinates to the joint locations throughout exercise. A second custom Matlab program was used to scale the data, calculate joint angles, estimate the foot center of pressure (COP), approximate normal and shear loads, and to create the VIS motion-corrected stick figure videos. Kinematics for the squat and deadlift vary considerably for the four crewmembers in this investigation. Some have very shallow knee and hip angles, and others have quite large ranges of motion at these joints. Joint angle analysis showed that crewmembers

  13. Amount of kinematic feedback affects learning of speech motor skills.

    Science.gov (United States)

    Ballard, Kirrie J; Smith, Heather D; Paramatmuni, Divija; McCabe, Patricia; Theodoros, Deborah G; Murdoch, Bruce E

    2012-01-01

    Knowledge of Performance (KP) feedback, such as biofeedback or kinematic feedback, is used to provide information on the nature and quality of movement responses for the purpose of guiding active learning or rehabilitation of motor skills. It has been proposed that KP feedback may interfere with long-term learning when provided throughout training. Here, twelve healthy English-speaking adults were trained to produce a trilled Russian [r] in words with KP kinematic feedback using electropalatography (EPG) and without KP (noKP). Five one-hour training sessions were provided over one week with testing pretraining and one day and one week posttraining. No group differences were found at pretraining or one day post training for production accuracy. A group by time interaction supported the hypothesis that providing kinematic feedback continually during skill acquisition interferes with retention.

  14. Nonlinear kinematics for piezoelectricity in ALEGRA-EMMA.

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, John Anthony; Fuller, Timothy Jesse

    2013-09-01

    This report develops and documents nonlinear kinematic relations needed to implement piezoelectric constitutive models in ALEGRA-EMMA [5], where calculations involving large displacements and rotations are routine. Kinematic relationships are established using Gausss law and Faradays law; this presentation on kinematics goes beyond piezoelectric materials and is applicable to all dielectric materials. The report then turns to practical details of implementing piezoelectric models in an application code where material principal axes are rarely aligned with user defined problem coordinate axes. This portion of the report is somewhat pedagogical but is necessary in order to establish documentation for the piezoelectric implementation in ALEGRA-EMMA. This involves transforming elastic, piezoelectric, and permittivity moduli from material principal axes to problem coordinate axes. The report concludes with an overview of the piezoelectric implementation in ALEGRA-EMMA and small verification examples.

  15. Pure Gravities via Color-Kinematics Duality for Fundamental Matter

    CERN Document Server

    Johansson, Henrik

    2015-01-01

    We give a prescription for the computation of loop-level scattering amplitudes in pure Einstein gravity, and four-dimensional pure supergravities, using the color-kinematics duality. Amplitudes are constructed using double copies of pure (super-)Yang-Mills parts and additional contributions from double copies of fundamental matter, which are treated as ghosts. The opposite-statistics states cancel the unwanted dilaton and axion in the bosonic theory, as well as the extra matter supermultiplets in supergravities. As a spinoff, we obtain a prescription for obtaining amplitudes in supergravities with arbitrary non-self-interacting matter. As a prerequisite, we extend the color-kinematics duality from the adjoint to the fundamental representation of the gauge group. We explain the numerator relations that the fundamental kinematic Lie algebra should satisfy. We give nontrivial evidence supporting our construction using explicit tree and loop amplitudes, as well as more general arguments.

  16. Nonlinear kinematic hardening under non-proportional loading

    International Nuclear Information System (INIS)

    Ottosen, N.S.

    1979-07-01

    Within the framework of conventional plasticity theory, it is first determined under which conditions Melan-Prager's and Ziegler's kinematic hardening rules result in identical material behaviour. Next, assuming initial isotropy and adopting the von Mises yield criterion, a nonlinear kinematic hardening function is proposed for prediction of metal behaviour. The model assumes that hardening at a specific stress point depends on the direction of the new incremental loading. Hereby a realistic response is obtained for general reversed loading, and a smooth behaviour is assured, even when loading deviates more and more from proportional loading and ultimately results in reversed loading. The predictions of the proposed model for non-proportional loading under plane stress conditions are compared with those of the classical linear kinematic model, the isotropic model and with published experimental data. Finally, the limitations of the proposaed model are discussed. (author)

  17. Kinematic variables of table vault on artistic gymnastics

    Directory of Open Access Journals (Sweden)

    Sarah Maria Boldrini FERNANDES

    2016-03-01

    Full Text Available Abstract The table vault is an event of male and female Artistics Gymnastics. Although it can be performed in a variety of rotations and body positions in different phases, it can be separated in three groups: handspring, Yurchenko and Tsukahara. It is believed that kinematic variables of vault may vary according to group of vault or gymnast body position, but few studies compares the real differences among the three groups of vaults, comparing and describing the variables in different phases. Vault kinematic variables could be diversifying according to the approach or position of the vaulting, but little has been studied about the biomechanical differences, comparing and describing behaviours at different stages. The aim of this study was to organize critical, objective and to systematize the most relevant kinematic variables to performance on vaulting. A Meta analysis over the basis Pubmed, Sport Discus and Web of Science were performed about this issue. From the selected references, we described and analyzed the kinematics of the table vault. Vault can be characterized in seven phases of analysis. Most of the studies are descriptive, and some do not descript all phases. Differences among vault variables according to group vaults, technical level and gender were analysed only in recent studies. There still gaps of knowledge about kinematic variables of table vault, in order to provide comprehensive information about all possibilities of vaults in this gymnastic event. It is concluded that kinematic variables of table vault depends upon vault group and may be considered to the improvement of technical performance. More researches are needed to approach the coaching interface with biomechanics applicable knowledge.

  18. Kinematics of a relativistic particle with de Sitter momentum space

    International Nuclear Information System (INIS)

    Arzano, Michele; Kowalski-Glikman, Jerzy

    2011-01-01

    We discuss kinematical properties of a free relativistic particle with deformed phase space in which momentum space is given by (a submanifold of) de Sitter space. We provide a detailed derivation of the action, Hamiltonian structure and equations of motion for such a free particle. We study the action of deformed relativistic symmetries on the phase space and derive explicit formulae for the action of the deformed Poincare group. Finally we provide a discussion on parametrization of the particle worldlines stressing analogies and differences with ordinary relativistic kinematics.

  19. Whole analogy between Daniel Bernoulli solution and direct kinematics solution

    Directory of Open Access Journals (Sweden)

    Filipović Mirjana

    2010-01-01

    Full Text Available In this paper, the relationship between the original Euler-Bernoulli's rod equation and contemporary knowledge is established. The solution which Daniel Bernoulli defined for the simplest conditions is essentially the solution of 'direct kinematics'. For this reason, special attention is devoted to dynamics and kinematics of elastic mechanisms configuration. The Euler-Bernoulli equation and its solution (used in literature for a long time should be expanded according to the requirements of the mechanisms motion complexity. The elastic deformation is a dynamic value that depends on the total mechanism movements dynamics. Mathematical model of the actuators comprises also elasticity forces.

  20. A Model of Parallel Kinematics for Machine Calibration

    DEFF Research Database (Denmark)

    Pedersen, David Bue; Bæk Nielsen, Morten; Kløve Christensen, Simon

    2016-01-01

    Parallel kinematics have been adopted by more than 25 manufacturers of high-end desktop 3D printers [Wohlers Report (2015), p.118] as well as by research projects such as the WASP project [WASP (2015)], a 12 meter tall linear delta robot for Additive Manufacture of large-scale components for cons......Parallel kinematics have been adopted by more than 25 manufacturers of high-end desktop 3D printers [Wohlers Report (2015), p.118] as well as by research projects such as the WASP project [WASP (2015)], a 12 meter tall linear delta robot for Additive Manufacture of large-scale components...

  1. Kinematic Analysis and Performance Evaluation of Novel PRS Parallel Mechanism

    Science.gov (United States)

    Balaji, K.; Khan, B. Shahul Hamid

    2018-02-01

    In this paper, a 3 DoF (Degree of Freedom) novel PRS (Prismatic-Revolute- Spherical) type parallel mechanisms has been designed and presented. The combination of striaght and arc type linkages for 3 DOF parallel mechanism is introduced for the first time. The performances of the mechanisms are evaluated based on the indices such as Minimum Singular Value (MSV), Condition Number (CN), Local Conditioning Index (LCI), Kinematic Configuration Index (KCI) and Global Conditioning Index (GCI). The overall reachable workspace of all mechanisms are presented. The kinematic measure, dexterity measure and workspace analysis for all the mechanism have been evaluated and compared.

  2. An introduction to the mathematics of ocular kinematics

    Directory of Open Access Journals (Sweden)

    Graeme E MacKenzie

    2006-12-01

    Full Text Available The research surrounding ocular kinematics has widespread applications including the study of binocular vision, virtual reality and the detec-tion of ocular and neurologic pathologies. This field promises to have a significant impact on optometric diagnostic techniques. This paper in-troduces the terminology used in the description of eye rotations and explores a number of the mathematical approaches pertinent to the topic of ocular kinematics.

  3. A Kinematic, Kevlar(registered) Suspension System for an ADR

    Science.gov (United States)

    Voellmer, George M.; Jackson, Michael L.; Shirron, Peter J.; Tuttle, James G.

    2003-01-01

    The High Resolution Airborne Wideband Camera (HAWC) and the Submillimeter And Far Infrared Experiment (SAFIRE) will use identical Adiabatic Demagnetization Refrigerators (ADR) to cool their bolometer detectors to 200mK and 100mK, respectively. In order to minimize thermal loads on the salt pill, a Kevlar@ suspension system is used to hold it in place. An innovative, kinematic suspension system is presented. The suspension system is unique in that it consists or two parts that can be assembled and tensioned offline, and later bolted onto the salt pill. The resulting assembly constrains each degree of freedom only once, yielding a kinematic, tensile structure.

  4. Alterations in knee kinematics after partial medial meniscectomy are activity dependent.

    Science.gov (United States)

    Edd, Shannon N; Netravali, Nathan A; Favre, Julien; Giori, Nicholas J; Andriacchi, Thomas P

    2015-06-01

    partial medial meniscectomy and highlight the importance of challenging the knee with activities of increased demands to detect differences in kinematics from the contralateral limb. With further investigation, these findings could help guide clinical rehabilitation of patients with torn meniscus tissue, especially in the context of the patients' increased risk of joint degeneration. © 2015 The Author(s).

  5. Vector field statistical analysis of kinematic and force trajectories.

    Science.gov (United States)

    Pataky, Todd C; Robinson, Mark A; Vanrenterghem, Jos

    2013-09-27

    When investigating the dynamics of three-dimensional multi-body biomechanical systems it is often difficult to derive spatiotemporally directed predictions regarding experimentally induced effects. A paradigm of 'non-directed' hypothesis testing has emerged in the literature as a result. Non-directed analyses typically consist of ad hoc scalar extraction, an approach which substantially simplifies the original, highly multivariate datasets (many time points, many vector components). This paper describes a commensurately multivariate method as an alternative to scalar extraction. The method, called 'statistical parametric mapping' (SPM), uses random field theory to objectively identify field regions which co-vary significantly with the experimental design. We compared SPM to scalar extraction by re-analyzing three publicly available datasets: 3D knee kinematics, a ten-muscle force system, and 3D ground reaction forces. Scalar extraction was found to bias the analyses of all three datasets by failing to consider sufficient portions of the dataset, and/or by failing to consider covariance amongst vector components. SPM overcame both problems by conducting hypothesis testing at the (massively multivariate) vector trajectory level, with random field corrections simultaneously accounting for temporal correlation and vector covariance. While SPM has been widely demonstrated to be effective for analyzing 3D scalar fields, the current results are the first to demonstrate its effectiveness for 1D vector field analysis. It was concluded that SPM offers a generalized, statistically comprehensive solution to scalar extraction's over-simplification of vector trajectories, thereby making it useful for objectively guiding analyses of complex biomechanical systems. © 2013 Published by Elsevier Ltd. All rights reserved.

  6. Effects of social intention on movement kinematics in cooperative actions

    Directory of Open Access Journals (Sweden)

    Francois eQuesque

    2013-10-01

    Full Text Available Optimal control models of biological movements are used to account for those internal variables that constrain voluntary goal-directed actions. They however do not take into account external environmental constraints as those associated to social intention. We investigated here the effects of the social context on kinematic characteristics of sequential actions consisting in placing an object on an initial pad (preparatory action before reaching and grasping as fast as possible the object to move it to another location (main action. Reach-to-grasp actions were performed either in an isolated condition or in the presence of a partner (audience effect, located in the near or far space (effect of shared reachable space, and who could intervene on the object in a systematic fashion (effect of social intention effect or not (effect of social uncertainty. Results showed an absence of audience effect but nevertheless an influence of the social context both on the main and the preparatory actions. In particular, a localized effect of shared reachable space was observed on the main action, which was smoother when performed within the reachable space of the partner. Furthermore, a global effect of social uncertainty was observed on both actions with faster and jerkier movements. Finally, social intention affected the preparatory action with higher wrist displacements and slower movements when the object was placed for the partner rather than placed for self-use. Overall, these results demonstrate specific effects of action space, social uncertainty and social intention on the planning of reach-to-grasp actions, in particular on the preparatory action, which was performed with no specific execution constraint. These findings underline the importance of considering the social context in optimal models of action control for human-robot interactions, in particular when focusing on the implementation of motor parameters required to afford intuitive

  7. A Novel Methodology for the Simulation of Athletic Tasks on Cadaveric Knee Joints with Respect to In Vivo Kinematics

    Science.gov (United States)

    Bates, Nathaniel A.; Nesbitt, Rebecca J.; Shearn, Jason T.; Myer, Gregory D.; Hewett, Timothy E.

    2015-01-01

    Six degree of freedom (6-DOF) robotic manipulators have simulated clinical tests and gait on cadaveric knees to examine knee biomechanics. However, these activities do not necessarily emulate the kinematics and kinetics that lead to anterior cruciate ligament (ACL) rupture. The purpose of this study was to determine the techniques needed to derive reproducible, in vitro simulations from in vivo skin-marker kinematics recorded during simulated athletic tasks. Input of raw, in vivo, skin-marker-derived motion capture kinematics consistently resulted in specimen failure. The protocol described in this study developed an in-depth methodology to adapt in vivo kinematic recordings into 6-DOF knee motion simulations for drop vertical jumps and sidestep cutting. Our simulation method repeatably produced kinetics consistent with vertical ground reaction patterns while preserving specimen integrity. Athletic task simulation represents an advancement that allows investigators to examine ACL-intact and graft biomechanics during motions that generate greater kinetics, and the athletic tasks are more representative of documented cases of ligament rupture. Establishment of baseline functional mechanics within the knee joint during athletic tasks will serve to advance the prevention, repair and rehabilitation of ACL injuries. PMID:25869454

  8. Effects of experimental insoles on body posture, mandibular kinematics and masticatory muscles activity. A pilot study in healthy volunteers.

    Science.gov (United States)

    Marini, Ida; Alessandri Bonetti, Giulio; Bortolotti, Francesco; Bartolucci, Maria Lavinia; Gatto, Maria Rosaria; Michelotti, Ambra

    2015-06-01

    It has been hypothesized that different plantar sensory inputs could influence the whole body posture and dental occlusion but there is a lack of evidence on this possible association. To investigate the effects of experimental insoles redistributing plantar pressure on body posture, mandibular kinematics and electromyographic (EMG) activity of masticatory muscles on healthy subjects. A pilot study was conducted on 19 healthy volunteers that wore custom-made insoles normalizing the plantar pressure distribution for 2 weeks. Body posture parameters were measured by means of an optoelectronic stereophotogrammetric analysis; mandibular kinematics was analyzed by means of gothic arch tracings; superficial EMG activity of head and neck muscles was performed. Measurements were carried out 10 days before the insertion of the insoles, immediately before the insertion, the day after, 7 and 14 days after, in four different exteroceptive conditions. The outcomes of the present study show that insoles do not modify significantly over time the parameters of body posture, SEMG activity of head and neck muscles and mandibular kinematics. In this pilot study the experimental insoles did not significantly influence the body posture, the mandibular kinematics and the activity of masticatory muscles during a 14-day follow up period. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Kinematics and dynamics of a six-degree-of-freedom robot manipulator with closed kinematic chain mechanism

    Science.gov (United States)

    Nguyen, Charles C.; Pooran, Farhad J.

    1989-01-01

    This paper deals with a class of robot manipulators built based on the kinematic chain mechanism (CKCM). This class of CKCM manipulators consists of a fixed and a moving platform coupled together via a number of in-parallel actuators. A closed-form solution is derived for the inverse kinematic problem of a six-degre-of-freedom CKCM manipulator designed to study robotic applications in space. Iterative Newton-Raphson method is employed to solve the forward kinematic problem. Dynamics of the above manipulator is derived using the Lagrangian approach. Computer simulation of the dynamical equations shows that the actuating forces are strongly dependent on the mass and centroid of the robot links.

  10. Kinematics and design of a class of parallel manipulators

    Science.gov (United States)

    Hertz, Roger Barry

    1998-12-01

    This dissertation is concerned with the kinematic analysis and design of a class of three degree-of-freedom, spatial parallel manipulators. The class of manipulators is characterized by two platforms, between which are three legs, each possessing a succession of revolute, spherical, and revolute joints. The class is termed the "revolute-spherical-revolute" class of parallel manipulators. Two members of this class are examined. The first mechanism is a double-octahedral variable-geometry truss, and the second is termed a double tripod. The history the mechanisms is explored---the variable-geometry truss dates back to 1984, while predecessors of the double tripod mechanism date back to 1869. This work centers on the displacement analysis of these three-degree-of-freedom mechanisms. Two types of problem are solved: the forward displacement analysis (forward kinematics) and the inverse displacement analysis (inverse kinematics). The kinematic model of the class of mechanism is general in nature. A classification scheme for the revolute-spherical-revolute class of mechanism is introduced, which uses dominant geometric features to group designs into 8 different sub-classes. The forward kinematics problem is discussed: given a set of independently controllable input variables, solve for the relative position and orientation between the two platforms. For the variable-geometry truss, the controllable input variables are assumed to be the linear (prismatic) joints. For the double tripod, the controllable input variables are the three revolute joints adjacent to the base (proximal) platform. Multiple solutions are presented to the forward kinematics problem, indicating that there are many different positions (assemblies) that the manipulator can assume with equivalent inputs. For the double tripod these solutions can be expressed as a 16th degree polynomial in one unknown, while for the variable-geometry truss there exist two 16th degree polynomials, giving rise to 256

  11. Multibody Kinematics Optimization for the Estimation of Upper and Lower Limb Human Joint Kinematics: A Systematized Methodological Review.

    Science.gov (United States)

    Begon, Mickaël; Andersen, Michael Skipper; Dumas, Raphaël

    2018-03-01

    Multibody kinematics optimization (MKO) aims to reduce soft tissue artefact (STA) and is a key step in musculoskeletal modeling. The objective of this review was to identify the numerical methods, their validation and performance for the estimation of the human joint kinematics using MKO. Seventy-four papers were extracted from a systematized search in five databases and cross-referencing. Model-derived kinematics were obtained using either constrained optimization or Kalman filtering to minimize the difference between measured (i.e., by skin markers, electromagnetic or inertial sensors) and model-derived positions and/or orientations. While hinge, universal, and spherical joints prevail, advanced models (e.g., parallel and four-bar mechanisms, elastic joint) have been introduced, mainly for the knee and shoulder joints. Models and methods were evaluated using: (i) simulated data based, however, on oversimplified STA and joint models; (ii) reconstruction residual errors, ranging from 4 mm to 40 mm; (iii) sensitivity analyses which highlighted the effect (up to 36 deg and 12 mm) of model geometrical parameters, joint models, and computational methods; (iv) comparison with other approaches (i.e., single body kinematics optimization and nonoptimized kinematics); (v) repeatability studies that showed low intra- and inter-observer variability; and (vi) validation against ground-truth bone kinematics (with errors between 1 deg and 22 deg for tibiofemoral rotations and between 3 deg and 10 deg for glenohumeral rotations). Moreover, MKO was applied to various movements (e.g., walking, running, arm elevation). Additional validations, especially for the upper limb, should be undertaken and we recommend a more systematic approach for the evaluation of MKO. In addition, further model development, scaling, and personalization methods are required to better estimate the secondary degrees-of-freedom (DoF).

  12. Interactive cervical motion kinematics: sensitivity, specificity and clinically significant values for identifying kinematic impairments in patients with chronic neck pain.

    Science.gov (United States)

    Sarig Bahat, Hilla; Chen, Xiaoqi; Reznik, David; Kodesh, Einat; Treleaven, Julia

    2015-04-01

    Chronic neck pain has been consistently shown to be associated with impaired kinematic control including reduced range, velocity and smoothness of cervical motion, that seem relevant to daily function as in quick neck motion in response to surrounding stimuli. The objectives of this study were: to compare interactive cervical kinematics in patients with neck pain and controls; to explore the new measures of cervical motion accuracy; and to find the sensitivity, specificity, and optimal cutoff values for defining impaired kinematics in those with neck pain. In this cross-section study, 33 patients with chronic neck pain and 22 asymptomatic controls were assessed for their cervical kinematic control using interactive virtual reality hardware and customized software utilizing a head mounted display with built-in head tracking. Outcome measures included peak and mean velocity, smoothness (represented by number of velocity peaks (NVP)), symmetry (represented by time to peak velocity percentage (TTPP)), and accuracy of cervical motion. Results demonstrated significant and strong effect-size differences in peak and mean velocities, NVP and TTPP in all directions excluding TTPP in left rotation, and good effect-size group differences in 5/8 accuracy measures. Regression results emphasized the high clinical value of neck motion velocity, with very high sensitivity and specificity (85%-100%), followed by motion smoothness, symmetry and accuracy. These finding suggest cervical kinematics should be evaluated clinically, and screened by the provided cut off values for identification of relevant impairments in those with neck pain. Such identification of presence or absence of kinematic impairments may direct treatment strategies and additional evaluation when needed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Phenomenological Analysis of the Kinematic Hardening of HSLA and IF Steels Using Reverse Simple Shear Tests

    International Nuclear Information System (INIS)

    Aouafi, A.; Bouvier, S.; Gasperini, M.; Lemoine, X.; Bouaziz, O.

    2007-01-01

    Reverse simple shear tests are used to analyse the Bauschinger effect and the evolution of the kinematic hardening for a wide range of equivalent von Mises strain [0.025 - 0.3]. This work is carried out on two high strength low-alloyed steels. In order to investigate the effect of the precipitates on the macroscopic behaviour, a ferritic mild steel is used as a reference. Different phenomenological descriptions of the back-stress tensor are examined in order to analyse their ability to describe the experimental behaviour

  14. The Numerical FEM Model of the Kinematics of the Vibratory Shot Peening Process

    Directory of Open Access Journals (Sweden)

    Stanisław Bławucki

    2017-12-01

    Full Text Available The paper presents the results of numerical calculations, with the finite element method in the ABAQUS program environment, of the vibratory shot peening process with loose peening elements. The behaviour of shot peening elements was analysed in the kinematic aspect. The impact of the initial deployment of vibratory shot peening elements on their behaviour during processing was investigated, including the displacement, velocity, acceleration and the number of collisions. The way of determining the effectiveness of the processing with the vibratory shot peening was illustrated.

  15. Correlation between transverse plan kinematics and foot progression angle in children with spastic diplegia.

    Science.gov (United States)

    Presedo, Ana; Simon, Anne-Laure; Mallet, Cindy; Ilharreborde, Brice; Mazda, Keyvan; Pennecot, Georges-François

    2017-05-01

    In diplegic patients, the orientation of foot progression depends on multiple factors. We investigated the relationship between foot progression alignment, hip and pelvic rotations during gait, femoral anteversion, and tibial torsion. Kinematic and clinical parameters were evaluated for 114 children who walked independently and had not undergone previous surgery. Causes of intoeing presented combined in 72% of cases. Internal foot progression correlated with internal hip rotation and showed an inverse correlation with tibial torsion. Our results indicate that data from clinical examination and gait analysis should be evaluated carefully before making treatment recommendations, especially in terms of the correction of torsional problems, in patients with cerebral palsy.

  16. Kinematic model of some types of motion of matter in active regions

    International Nuclear Information System (INIS)

    Platov, Yu.V.

    1983-01-01

    The kinematics of matter motion in variable magnetic fields of active regions on the Sun in the MHD approximation of a strong field and cold plasma is investigated. It is shown that the variation of sunspot magnetic moments lead to the development of different active phenomena in the solar atmosphere. The development of such phenomena at first can occur at the phase of active region growth, when new sunspots together with developed sunspots emerge in an active region or relative motions take place in a sunspot group

  17. Kinematic fitting of neutral current events at HERA

    International Nuclear Information System (INIS)

    Chaves, H.; Seifert, R.J.; Zech, G.

    1993-01-01

    The measurement of the scaling variables in deep inelastic scattering at HERA can be improved considerably by constraining the scattered electrons and the produced hadrons to energy-momentum conservation. It is shown how unobserved particles moving down the beam pipe and initial state radiation can be included in the kinematics. The particle momenta are adjusted in a linear least squares fit. (orig.)

  18. Test-retest reliability of knee kinematics measurement during gait ...

    African Journals Online (AJOL)

    ACLR) is crucial to minimize the risk of joint degeneration. To achieve this, it is essential that the chosen measurement method can accurately assess knee kinematics and detect the changes in multi-planes of motion. However to date, limited ...

  19. Adding Image Constraints to Inverse Kinematics for Human Motion Capture

    Science.gov (United States)

    Jaume-i-Capó, Antoni; Varona, Javier; González-Hidalgo, Manuel; Perales, Francisco J.

    2009-12-01

    In order to study human motion in biomechanical applications, a critical component is to accurately obtain the 3D joint positions of the user's body. Computer vision and inverse kinematics are used to achieve this objective without markers or special devices attached to the body. The problem of these systems is that the inverse kinematics is "blinded" with respect to the projection of body segments into the images used by the computer vision algorithms. In this paper, we present how to add image constraints to inverse kinematics in order to estimate human motion. Specifically, we explain how to define a criterion to use images in order to guide the posture reconstruction of the articulated chain. Tests with synthetic images show how the scheme performs well in an ideal situation. In order to test its potential in real situations, more experiments with task specific image sequences are also presented. By means of a quantitative study of different sequences, the results obtained show how this approach improves the performance of inverse kinematics in this application.

  20. Static And Kinematic Formulation Of Planar Reciprocal Assemblies

    DEFF Research Database (Denmark)

    Parigi, Dario; Kirkegaard, Poul Henning

    2013-01-01

    Planar reciprocal frames are two dimensional structures formed by elements joined together according to the principle of structural reciprocity. In this paper a rigorous formulation of the static and kinematic problem is proposed and developed by extending the work on pin-jointed assemblies by Pe...

  1. UPPER EXTREMITY KINEMATICS OF FLAT SERVE IN TENNIS ...

    African Journals Online (AJOL)

    Brian McAllister

    kinematics on the ball velocity at the impact phase of a tennis flat serve. 15 elite male tennis players were recruited to participate in this study (mean age 18.4±3.3 .... For field calibration, a Direct Linear Transformation technique, developed by ...

  2. On Einstein's kinematics and his derivation of Lorentz transformation equations

    International Nuclear Information System (INIS)

    Gulati, Shobha; Gulati, S.P.

    1981-01-01

    Recently the present authors have claimed that Einstein's historic derivation of 1905 of Lorentz transformation equations is a 'howler' - a correct result achieved through some incorrect steps. In the present contribution, this howler is fully resolved. Incidently, Einstein's kinematical considerations are found to be void of any new definitional elements or conventionality as unjustifiably claimed by Einstein and some other scientists. (author)

  3. Statics and kinematics of discrete Cosserat-type granular materials

    NARCIS (Netherlands)

    Kruyt, Nicolaas P.

    2003-01-01

    A theoretical framework is presented for the statics and kinematics of discrete Cosserat-type granular materials. In analogy to the force and moment equilibrium equations for particles, compatibility equations for closed loops are formulated in the two-dimensional case for relative displacements and

  4. Galileo's kinematical paradox and the role of resistive forces

    International Nuclear Information System (INIS)

    Aguiar, C E; Soares, V; Tort, A C

    2014-01-01

    We discuss Galileo's kinematical ‘paradox’ taking into account the effects of sliding friction and of resistive forces proportional to velocity. We show that sliding friction eliminates the paradox but still allows for very simple synchronous curves. Perhaps surprisingly, Galileo's paradox is preserved when the resistive force is proportional to velocity. (paper)

  5. Soft tissue artifact in canine kinematic gait analysis

    NARCIS (Netherlands)

    Schwencke, M.; Smolders, L.A.; Bergknut, N.; Gustas, P.; Meij, B.P.; Hazewinkel, H.A.W.

    2012-01-01

    Vet Surg. 2012 Oct;41(7):829-37. doi: 10.1111/j.1532-950X.2012.01021.x. Soft tissue artifact in canine kinematic gait analysis. Schwencke M, Smolders LA, Bergknut N, Gustås P, Meij BP, Hazewinkel HA. Source Department of Clinical Sciences of Companion Animals,, Faculty of Veterinary Medicine,

  6. Modern techniques in galaxy kinematics : Results from planetary nebula spectroscopy

    NARCIS (Netherlands)

    Romanowsky, AJ; Douglas, NG; Kuijken, K; Arnaboldi, M; Gerssen, J; Merrifield, MR; Kwok, S; Dopita, M; Sutherland, R

    2003-01-01

    We have observed planetary nebulae (PNe) in several early-type galaxies using new techniques on 4- to 8-meter-class telescopes. We obtain the first large data sets (greater than or similar to 100 velocities each) of PN kinematics in galaxies at greater than or similar to 15 Mpc, and present some

  7. Kinematic Measures of Imitation Fidelity in Primary School Children

    Science.gov (United States)

    Williams, Justin H. G.; Casey, Jackie M.; Braadbaart, Lieke; Culmer, Peter R.; Mon-Williams, Mark

    2014-01-01

    We sought to develop a method for measuring imitation accuracy objectively in primary school children. Children imitated a model drawing shapes on the same computer-tablet interface they saw used in video clips, allowing kinematics of model and observers' actions to be directly compared. Imitation accuracy was reported as a correlation reflecting…

  8. Is Active Tectonics on Madagascar Consistent with Somalian Plate Kinematics?

    Science.gov (United States)

    Stamps, D. S.; Kreemer, C.; Rajaonarison, T. A.

    2017-12-01

    The East African Rift System (EARS) actively breaks apart the Nubian and Somalian tectonic plates. Madagascar finds itself at the easternmost boundary of the EARS, between the Rovuma block, Lwandle plate, and the Somalian plate. Earthquake focal mechanisms and N-S oriented fault structures on the continental island suggest that Madagascar is experiencing east-west oriented extension. However, some previous plate kinematic studies indicate minor compressional strains across Madagascar. This inconsistency may be due to uncertainties in Somalian plate rotation. Past estimates of the rotation of the Somalian plate suffered from a poor coverage of GPS stations, but some important new stations are now available for a re-evaluation. In this work, we revise the kinematics of the Somalian plate. We first calculate a new GPS velocity solution and perform block kinematic modeling to evaluate the Somalian plate rotation. We then estimate new Somalia-Rovuma and Somalia-Lwandle relative motions across Madagascar and evaluate whether they are consistent with GPS measurements made on the island itself, as well as with other kinematic indicators.

  9. Kinematics analysis of a robotic zipper prototype for miniaturisation

    NARCIS (Netherlands)

    Baharom, M.Z.; Delbressine, F.L.M.; Feijs, L.M.G.

    2016-01-01

    This paper presents the mechanism and kinematics analysis of a robotic zipper prototype. This generic version of the robotic zipper is dedicated to automatically open and close the zipper which could be beneficial to elderly, people with physical disability, upper limb reduction deficiencies (ULRD),

  10. Differences in Soccer Kick Kinematics between Blind Players and Controls

    Science.gov (United States)

    Giagazoglou, Paraskevi; Katis, Athanasios; Kellis, Eleftherios; Natsikas, Christos

    2011-01-01

    The purpose of the current study was to examine the kinematic differences during instep soccer kicks between players who were blind and sighted controls. Eleven male soccer players who were blind and nine male sighted performed instep kicks under static and dynamic conditions. The results indicated significantly higher (p less than 0.05) ball…

  11. Kinematics and simulation methods to determine the target thickness

    International Nuclear Information System (INIS)

    Rosales, P.; Aguilar, E.F.; Martinez Q, E.

    2001-01-01

    Making use of the kinematics and of the particles energy loss two methods for calculating the thickness of a target are described. Through a computer program and other of simulation in which parameters obtained experimentally are used. Several values for a 12 C target thickness were obtained. It is presented a comparison of the obtained values with each one of the used programs. (Author)

  12. Kinematic signature of a rotating bar near a resonance

    Science.gov (United States)

    Weinberg, Martin D.

    1994-01-01

    Recent work based on H I, star count and emission data suggests that the Milky Way has rotating bar-like features. In this paper, I show that such features cause distinctive stellar kinematic signatures near Outer Lindblad Resonance (OLR) and Inner Lindblad Resonance (ILR). The effect of these resonances may be observable far from the peak density of the pattern and relatively nearby the solar position. The details of the kinematic signatures depend on the evolutionary history of the 'bar' and therefore velocity data, both systematic and velocity dispersion, may be used to probe the evolutionary history as well as the present state of Galaxy. Kinematic models for a variety of sample scenarios are presented. Models with evolving pattern speeds show significantly stronger dispersion signatures than those with static pattern speeds, suggesting that useful observational constraints are possible. The models are applied to the proposed rotating spheroid and bar models; we find (1) none of these models chosen to represent the proposed large-scale rotating spheroid are consistent with the stellar kinematics and (2) a Galactic bar with semimajor axis of 3 kpc will cause a large increase in velocity dispersion in the vicinity of OLR (approximately 5 kpc) with little change in the net radial motion and such a signature is suggested by K-giant velocity data. Potential future observations and analyses are discussed.

  13. Using Robotics in Kinematics Classes: Exploring Braking and Stopping Distances

    Science.gov (United States)

    Brockington, Guilherme; Schivani, Milton; Barscevicius, Cesar; Raquel, Talita; Pietrocola, Maurício

    2018-01-01

    Research in the field of physics teaching has revealed high school students' difficulties in establishing relations between kinematic equations and real movements. Moreover, there are well-known and significant challenges in their comprehension of graphic language content. Thus, this article explores a didactic activity which utilized robotics in…

  14. A digital database of wrist bone anatomy and carpal kinematics.

    Science.gov (United States)

    Moore, Douglas C; Crisco, Joseph J; Trafton, Theodore G; Leventhal, Evan L

    2007-01-01

    The skeletal wrist consists of eight small, intricately shaped carpal bones. The motion of these bones is complex, occurs in three dimensions, and remains incompletely defined. Our previous efforts have been focused on determining the in vivo three-dimensional (3-D) kinematics of the normal and abnormal carpus. In so doing we have developed an extensive database of carpal bone anatomy and kinematics from a large number of healthy subjects. The purpose of this paper is to describe that database and to make it available to other researchers. CT volume images of both wrists from 30 healthy volunteers (15 males and 15 females) were acquired in multiple wrist positions throughout the normal range of wrist motion. The outer cortical surfaces of the carpal bones, radius and ulna, and proximal metacarpals were segmented and the 3-D motion of each bone was calculated for each wrist position. The database was constructed to include high-resolution surface models, measures of bone volume and shape, and the 3-D kinematics of each segmented bone. The database does not include soft tissues of the wrist. While there are numerous digital anatomical databases, this one is unique in that it includes a large number of subjects and it contains in vivo kinematic data as well as the bony anatomy.

  15. Circular braiding take-up speed generation using inverse kinematics

    NARCIS (Netherlands)

    van Ravenhorst, J.H.; Akkerman, Remko

    2014-01-01

    Circular overbraiding of composite preforms on complex mandrels currently lacks automatic generation of machine control data. To solve this limitation, an inverse kinematics-based procedure was designed and implemented for circular braiding machines with optional guide rings, resulting in a take-up

  16. Hallux valgus surgery affects kinematic parameters during gait.

    Science.gov (United States)

    Klugarova, Jitka; Janura, Miroslav; Svoboda, Zdenek; Sos, Zdenek; Stergiou, Nicholas; Klugar, Miloslav

    2016-12-01

    The aim of our study was to compare spatiotemporal parameters and lower limb and pelvis kinematics during the walking in patients with hallux valgus before and after surgery and in relation to a control group. Seventeen females with hallux valgus, who underwent first metatarsal osteotomy, constituted our experimental group. The control group consisted of thirteen females. Kinematic data during walking were obtained using the Vicon MX system. Our results showed that hallux valgus before surgery affects spatiotemporal parameters and lower limb and pelvis kinematics during walking. Hallux valgus surgery further increased the differences that were present before surgery. Specifically after hallux valgus surgery, the walking speed decreased even more (p=0.09, η 2 =0.19) while step time increased (p=0.002, η 2 =0.44) on both legs. The maximum ankle plantar flexion of the operated leg during toe-off decreased to a greater extend (p=0.03, η 2 =0.26). The asymmetry in the hip and the pelvis movements in the frontal plane (present preoperatively) persisted after surgery. Hallux valgus is not an isolated problem of the first ray, which could be just surgically addressed by correcting the foot's alignment. It is a long-term progressive malfunction of the foot affecting the entire kinematic chain of the lower extremity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Kinematic Identification of Parallel Mechanisms by a Divide and Conquer Strategy

    DEFF Research Database (Denmark)

    Durango, Sebastian; Restrepo, David; Ruiz, Oscar

    2010-01-01

    using the inverse calibration method. The identification poses are selected optimizing the observability of the kinematic parameters from a Jacobian identification matrix. With respect to traditional identification methods the main advantages of the proposed Divide and Conquer kinematic identification...... strategy are: (i) reduction of the kinematic identification computational costs, (ii) improvement of the numerical efficiency of the kinematic identification algorithm and, (iii) improvement of the kinematic identification results. The contributions of the paper are: (i) The formalization of the inverse...... calibration method as the Divide and Conquer strategy for the kinematic identification of parallel symmetrical mechanisms and, (ii) a new kinematic identification protocol based on the Divide and Conquer strategy. As an application of the proposed kinematic identification protocol the identification...

  18. Six degree-of-freedom knee joint kinematics in obese individuals with knee pain during gait.

    Science.gov (United States)

    Li, Jing-Sheng; Tsai, Tsung-Yuan; Felson, David T; Li, Guoan; Lewis, Cara L

    2017-01-01

    Knee joint pain is a common symptom in obese individuals and walking is often prescribed as part of management programs. Past studies in obese individuals have focused on standing alignment and kinematics in the sagittal and coronal planes. Investigation of 6 degree-of-freedom (6DOF) knee joint kinematics during standing and gait is important to thoroughly understand knee function in obese individuals with knee pain. This study aimed to investigate the 6DOF knee joint kinematics in standing and during gait in obese patients using a validated fluoroscopic imaging system. Ten individuals with obesity and knee pain were recruited. While standing, the knee was in 7.4±6.3°of hyperextension, 2.8±3.3° of abduction and 5.6±7.3° of external rotation. The femoral center was located 0.7±3.1mm anterior and 5.1±1.5mm medial to the tibial center. During treadmill gait, the sagittal plane motion, i.e., flexion/extension and anterior-posterior translation, showed a clear pattern. Specifically, obese individuals with knee pain maintained the knee in more flexion and more anterior tibial translation during most of the stance phase of the gait cycle and had a reduced total range of knee flexion when compared to a healthy non-obese group. In conclusion, obese individuals with knee pain used hyperextension knee posture while standing, but maintained the knee in more flexion during gait with reduced overall range of motion in the 6DOF analysis.

  19. Landslide Kinematical Analysis through Inverse Numerical Modelling and Differential SAR Interferometry

    Science.gov (United States)

    Castaldo, R.; Tizzani, P.; Lollino, P.; Calò, F.; Ardizzone, F.; Lanari, R.; Guzzetti, F.; Manunta, M.

    2015-11-01

    The aim of this paper is to propose a methodology to perform inverse numerical modelling of slow landslides that combines the potentialities of both numerical approaches and well-known remote-sensing satellite techniques. In particular, through an optimization procedure based on a genetic algorithm, we minimize, with respect to a proper penalty function, the difference between the modelled displacement field and differential synthetic aperture radar interferometry (DInSAR) deformation time series. The proposed methodology allows us to automatically search for the physical parameters that characterize the landslide behaviour. To validate the presented approach, we focus our analysis on the slow Ivancich landslide (Assisi, central Italy). The kinematical evolution of the unstable slope is investigated via long-term DInSAR analysis, by exploiting about 20 years of ERS-1/2 and ENVISAT satellite acquisitions. The landslide is driven by the presence of a shear band, whose behaviour is simulated through a two-dimensional time-dependent finite element model, in two different physical scenarios, i.e. Newtonian viscous flow and a deviatoric creep model. Comparison between the model results and DInSAR measurements reveals that the deviatoric creep model is more suitable to describe the kinematical evolution of the landslide. This finding is also confirmed by comparing the model results with the available independent inclinometer measurements. Our analysis emphasizes that integration of different data, within inverse numerical models, allows deep investigation of the kinematical behaviour of slow active landslides and discrimination of the driving forces that govern their deformation processes.

  20. Ontogenetic scaling of locomotor kinetics and kinematics of the ostrich (Struthio camelus).

    Science.gov (United States)

    Smith, Nicola C; Jespers, Karin J; Wilson, Alan M

    2010-04-01

    Kinematic and kinetic parameters of running gait were investigated through growth in the ostrich, from two weeks up to 10 months of age, in order to investigate the effects of increasing body size. Ontogenetic scaling relationships were compared with published scaling relationships found to exist with increasing body size between species to determine whether dynamic similarity is maintained during growth. During the study, ostrich mass (M(b)) ranged from 0.7 kg to 108.8 kg. Morphological measurements showed that lengths scaled with positive allometry during growth (hip height proportional to M(b)(0.40); foot segment length proportional to M(b)(0.40); tarsometatarsus length proportional to M(b)(0.41); tibiotarsus length proportional to M(b)(0.38); femur length proportional to M(b)(0.37)), significantly exceeding the close to geometric scaling observed between mammalian and avian species of increasing body size. Scaling of kinematic variables largely agreed with predicted scaling for increasing size and demonstrated relationships close to dynamic similarity and, as such, ontogenetic scaling of locomotor parameters was similar to that observed with increasing body mass between species. However, the ways in which these scaling trends were achieved were very different, with ontogenetic scaling of locomotor mechanics largely resulting from simple scaling of the limb segments rather than postural changes, likely to be due to developmental constraints. Small deviations from dynamic similarity of kinematic parameters and a reduction in the predicted scaling of limb stiffness (proportional to M(b)(0.59)) were found to be accounted for by the positive allometric scaling of the limb during growth.

  1. Differences in kinematic control of ankle joint motions in people with chronic ankle instability.

    Science.gov (United States)

    Kipp, Kristof; Palmieri-Smith, Riann M

    2013-06-01

    People with chronic ankle instability display different ankle joint motions compared to healthy people. The purpose of this study was to investigate the strategies used to control ankle joint motions between a group of people with chronic ankle instability and a group of healthy, matched controls. Kinematic data were collected from 11 people with chronic ankle instability and 11 matched control subjects as they performed a single-leg land-and-cut maneuver. Three-dimensional ankle joint angles were calculated from 100 ms before, to 200 ms after landing. Kinematic control of the three rotational ankle joint degrees of freedom was investigated by simultaneously examining the three-dimensional co-variation of plantarflexion/dorsiflexion, toe-in/toe-out rotation, and inversion/eversion motions with principal component analysis. Group differences in the variance proportions of the first two principal components indicated that the angular co-variation between ankle joint motions was more linear in the control group, but more planar in the chronic ankle instability group. Frontal and transverse plane motions, in particular, contributed to the group differences in the linearity and planarity of angular co-variation. People with chronic ankle instability use a different kinematic control strategy to coordinate ankle joint motions during a single-leg landing task. Compared to the healthy group, the chronic ankle instability group's control strategy appeared to be more complex and involved joint-specific contributions that would tend to predispose this group to recurring episodes of instability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Software Development for the Kinematic Analysis of a Lynx 6 Robot Arm

    OpenAIRE

    Baki Koyuncu; Mehmet Güzel

    2007-01-01

    The kinematics of manipulators is a central problem in the automatic control of robot manipulators. Theoretical background for the analysis of the 5 Dof Lynx-6 educational Robot Arm kinematics is presented in this paper. The kinematics problem is defined as the transformation from the Cartesian space to the joint space and vice versa. The Denavit-Harbenterg (D-H) model of representation is used to model robot links and joints in this study. Both forward and inverse kinematics solutions for th...

  3. STRUCTURAL IDENTIFICATION OF DISTINCT INVERSIONS OF PLANAR KINEMATIC CHAINS

    Directory of Open Access Journals (Sweden)

    Dr. Shubhashis Sanyal

    2011-12-01

    Full Text Available 0 0 1 171 979 International Islamic University 8 2 1148 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Times New Roman";} Inversions are various structural possibilities of a kinematic chain. The number of inversions depends on the number of links of a kinematic chain. At the stage of structural synthesis, identification of distinct structural inversions of a particular type of kinematic chain is necessary. Various researchers have proposed methods for identification of distinct inversions. Present method based on Link joint connectivity is proposed to identify the distinct inversions of a planar kinematic chain. Method is tested successfully on single degree and multiple degree of freedom planar kinematic chains. ABSTRAK: Penyonsangan merupakan kebarangkalian pelbagai struktur suatu rangkaian kinematik. Jumlah songsangan bergantung kepada jumlah hubungan suatu rangkaian kinematik. Pada peringkat sintesis struktur, pengenalan songsangan struktur yang berbeza untuk suatu jenis rangkaian kinematik adalah perlu. Ramai penyelidik telah mencadangkan pelbagai kaedah pengenalan songsangan yang berbeza. Kaedah terkini berdasarkan hubungan kesambungan bersama telah dicadangkan untuk mengenalpasti songsangan yang berbeza dalam suatu satah rangkaian kinematik.

  4. Fatigue effects on bar kinematics during the bench press.

    Science.gov (United States)

    Duffey, Michael J; Challis, John H

    2007-05-01

    The bench press is one of the most popular weight training exercises. Although most training regimens incorporate multiple repetition sets, there are few data describing how the kinematics of a lift change during a set to failure. To examine these changes, recreational lifters (10 men and 8 women) were recruited. The maximum weight each subject could bench press (1RM) was determined. Subjects then performed as many repetitions as possible at 75% of the 1RM load. Three-dimensional kinematic data were recorded and analyzed for all lifts. Statistical analysis revealed that differences between maximal and submaximal lifts and the kinematics of a submaximal lift change as a subject approaches failure in a set. The time to lift the bar more than doubled from the first to the last repetition, causing a decrease in both mean and peak upward velocity. Furthermore, the peak upward velocity occurred much earlier in the lift phase in these later repetitions. The path the bar followed also changed, with subjects keeping the bar more directly over the shoulder during the lift. In general, most of the kinematic variables analyzed became more similar to those of the maximal lift as the subjects progressed through the set, but there was considerable variation between subjects as to which repetition was most like the maximal lift. This study shows that there are definite changes in the lifting kinematics in recreational lifters during a set to failure and suggests it may be particularly important for coaches and less-skilled lifters to focus on developing the proper bar path, rather than reaching momentary muscular failure, in the early part of a training program.

  5. Surgical gesture classification from video and kinematic data.

    Science.gov (United States)

    Zappella, Luca; Béjar, Benjamín; Hager, Gregory; Vidal, René

    2013-10-01

    Much of the existing work on automatic classification of gestures and skill in robotic surgery is based on dynamic cues (e.g., time to completion, speed, forces, torque) or kinematic data (e.g., robot trajectories and velocities). While videos could be equally or more discriminative (e.g., videos contain semantic information not present in kinematic data), they are typically not used because of the difficulties associated with automatic video interpretation. In this paper, we propose several methods for automatic surgical gesture classification from video data. We assume that the video of a surgical task (e.g., suturing) has been segmented into video clips corresponding to a single gesture (e.g., grabbing the needle, passing the needle) and propose three methods to classify the gesture of each video clip. In the first one, we model each video clip as the output of a linear dynamical system (LDS) and use metrics in the space of LDSs to classify new video clips. In the second one, we use spatio-temporal features extracted from each video clip to learn a dictionary of spatio-temporal words, and use a bag-of-features (BoF) approach to classify new video clips. In the third one, we use multiple kernel learning (MKL) to combine the LDS and BoF approaches. Since the LDS approach is also applicable to kinematic data, we also use MKL to combine both types of data in order to exploit their complementarity. Our experiments on a typical surgical training setup show that methods based on video data perform equally well, if not better, than state-of-the-art approaches based on kinematic data. In turn, the combination of both kinematic and video data outperforms any other algorithm based on one type of data alone. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation.

    Science.gov (United States)

    Nataraj, Raviraj; Audu, Musa L; Triolo, Ronald J

    2012-05-06

    The purpose of this study was to determine the comparative effectiveness of feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM acceleration feedback alone, and combined joint kinematics and COM acceleration feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS), and the resulting joint kinematics and COM acceleration data was analyzed. Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics feedback and 35% for COM acceleration feedback. Pilot data indicated that COM acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Overall, COM acceleration feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small number of inputs required.

  7. Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation

    Directory of Open Access Journals (Sweden)

    Nataraj Raviraj

    2012-05-01

    Full Text Available Abstract Background The purpose of this study was to determine the comparative effectiveness of feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI. Methods In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM acceleration feedback alone, and combined joint kinematics and COM acceleration feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS, and the resulting joint kinematics and COM acceleration data was analyzed. Results Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics feedback and 35% for COM acceleration feedback. Pilot data indicated that COM acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Conclusions Overall, COM acceleration feedback may be a more feasible solution for control of standing with FNS given its

  8. Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study.

    Directory of Open Access Journals (Sweden)

    Vincent Richard

    Full Text Available The use of multi-body optimisation (MBO to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a "soft" constraint using a penalty-based method, this elastic joint description challenges the strictness of "hard" constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm. The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO.

  9. Intraoperative joint gaps and mediolateral balance affect postoperative knee kinematics in posterior-stabilized total knee arthroplasty.

    Science.gov (United States)

    Watanabe, Toshifumi; Muneta, Takeshi; Sekiya, Ichiro; Banks, Scott A

    2015-12-01

    Adjusting joint gaps and establishing mediolateral (ML) soft tissue balance are considered essential interventions for better outcomes in total knee arthroplasty (TKA). However, the relationship between intraoperative laxity measurements and weightbearing knee kinematics has not been well explored. This study aimed to quantify the effect of intraoperative joint gaps and ML soft tissue balance on postoperative knee kinematics in posterior-stabilized (PS)-TKA. We investigated 44 knees in 34 patients who underwent primary PS-TKA by a single surgeon. The central joint gaps and ML tilting angles at 0°, 10°, 30°, 60°, 90°, 120° and 135° flexion were measured during surgery. At a minimum of two year follow-up, we analyzed in vivo kinematics of these knees and examined the influence of intraoperative measurements on postoperative kinematics. Gap difference of knee flexion at 135° minus 0° was correlated with the total posterior translation of lateral femoral condyle (r=0.336, p=0.042) and femoral external rotation (r=0.488, p=0.002) during squatting, anteroposterior position of lateral femoral condyle (r=-0.510, p=0.001) and maximum knee flexion (r=0.355, p=0.031) in kneeling. Similar correlations were observed between deep flexion gap differences with respect to the 90° reference and postoperative knee kinematics. Well-balanced knees showed less anterior translation of medial femoral condyle in mid- to deep flexion, consistent femoral external rotation, and the most neutral valgus/varus rotation compared with unbalanced knees. These findings indicate the importance of adequate intraoperative joint gaps in deep flexion and ML soft tissue balance throughout the range of motion. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Post-cam mechanics and tibiofemoral kinematics: a dynamic in vitro analysis of eight posterior-stabilized total knee designs.

    Science.gov (United States)

    Arnout, N; Vanlommel, L; Vanlommel, J; Luyckx, J P; Labey, L; Innocenti, B; Victor, J; Bellemans, J

    2015-11-01

    Posterior cruciate ligament (PCL)-substituting total knee arthroplasty (TKA) designs were introduced to avoid paradoxical roll forward of the femur and to optimize knee kinematics. The aim of this in vitro study was to investigate post-cam function and contact mechanics and relate it to knee kinematics during squatting in eight contemporary posterior-stabilized TKA designs. All prostheses were fixed on custom-designed metal fixtures and mounted in a knee rig and five sequential-loaded squats were performed between 30° and 130° of flexion. Contact pressure and contact area were measured using pressure-sensitive Tekscan sensors on the posterior face of the post. Kinematics was recorded with reflective markers and infrared light-capturing cameras. The post-cam mechanisms analyzed in this study are very variable in terms of design features. This leads to large variations in terms of the flexion angle at which the post and cam engage maximal contact force, contact pressure and contact area. We found that more functional post-cam mechanisms, which engage at lower flexion angle and have a similar behavior as normal PCL function, generally show more normal rollback and tibial rotation at the expense of higher contact forces and pressures. All designs show high contact forces. A positive correlation was found between contact force and initial contact angle. Post-cam contact mechanics and kinematics were documented in a standardized setting. Post-cam contact mechanics are correlated with post-cam function. Outcomes of this study can help to develop more functional designs in future. Nevertheless, a compromise will always be made between functional requirements and risk of failure. We assume that more normal knee kinematics leads to more patient satisfaction because of better mobility. Understanding of the post-cam mechanism, and knowing how this system really works, is maybe the clue in further development of new total knee designs.

  11. Influence of new military athletic footwear on the kinetics and kinematics of running in relation to army boots.

    Science.gov (United States)

    Sinclair, Jonathan; Taylor, Paul J

    2014-10-01

    Musculoskeletal injuries in the lower extremities are common in military recruits. Army boots have frequently been cited as a potential mechanism behind these high injury rates. In response to this, the British Army introduced new footwear models, the PT-03 (cross-trainer) and PT1000 (running shoes), which are issued to each new recruit in an attempt to reduce the incidence of these injuries. The aim of the current investigation was to examine the kinetics and kinematic of the PT-03 and PT1000 footwear in relation to conventional army boots. Thirteen participants ran at 4.0 m·s in each footwear condition. Three-dimensional kinematics from the hip, knee, and ankle were measured using an 8-camera motion analysis system. In addition, simultaneous ground reaction forces were obtained. Kinetic parameters were obtained alongside joint kinematics and compared using repeated-measures analyses of variance. The kinetic analysis revealed that impact parameters were significantly greater when running in the army boot compared with the PT-03 and PT1000. The kinematic analysis indicated that, in comparison with the PT-03 and PT1000, running in army boots was associated with significantly greater eversion and tibial internal rotation. It was also found that when running in the PT-03 footwear, participants exhibited significantly greater hip adduction and knee abduction compared with the army boots and PT1000. The results of this study suggest that the army boots and PT-03 footwear are associated with kinetic and kinematic parameters that have been linked to the etiology of injury; thus, it is recommended that the PT1000 footwear be adopted for running exercises.

  12. Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study.

    Science.gov (United States)

    Richard, Vincent; Lamberto, Giuliano; Lu, Tung-Wu; Cappozzo, Aurelio; Dumas, Raphaël

    2016-01-01

    The use of multi-body optimisation (MBO) to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a "soft" constraint using a penalty-based method, this elastic joint description challenges the strictness of "hard" constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint) were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm) or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm) were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm). The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO.

  13. Kinematics of Disease Progression in Bulbar ALS

    Science.gov (United States)

    Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne

    2010-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…

  14. Wheel skid correction is a prerequisite to reliably measure wheelchair sports kinematics based on inertial sensors

    NARCIS (Netherlands)

    Van der Slikke, R.M.A.; Berger, M.A.M.; Bregman, D.J.J.; Veeger, H.E.J.

    2015-01-01

    Accurate knowledge of wheelchair kinematics during a match could be a significant factor in performance improvement in wheelchair basketball. To date, most systems for measuring wheelchair kinematics are not suitable for match applications or lack detail in key kinematic outcomes. This study

  15. Manual Skill Acquisition During Transesophageal Echocardiography Simulator Training of Cardiology Fellows: A Kinematic Assessment.

    Science.gov (United States)

    Matyal, Robina; Montealegre-Gallegos, Mario; Mitchell, John D; Kim, Han; Bergman, Remco; Hawthorne, Katie M; O'Halloran, David; Wong, Vanessa; Hess, Phillip E; Mahmood, Feroze

    2015-12-01

    To investigate whether a transesophageal echocardiography (TEE) simulator with motion analysis can be used to impart proficiency in TEE in an integrated curriculum-based model. A prospective cohort study. A tertiary-care university hospital. TEE-naïve cardiology fellows. Participants underwent an 8-session multimodal TEE training program. Manual skills were assessed at the end of sessions 2 and 8 using motion analysis of the TEE simulator's probe. At the end of the course, participants performed an intraoperative TEE; their examinations were video captured, and a blinded investigator evaluated the total time and image transitions needed for each view. Results are reported as mean±standard deviation, or median (interquartile range) where appropriate. Eleven fellows completed the knowledge and kinematic portions of the study. Five participants were excluded from the evaluation in the clinical setting because of interim exposure to TEE or having participated in a TEE rotation after the training course. An increase of 12.95% in post-test knowledge scores was observed. From the start to the end of the course, there was a significant reduction (pcardiology fellows can be complemented with kinematic analyses to objectify acquisition of manual skills during simulator-based training. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Direct reactions in inverse kinematics for nuclear structure studies far off stability at low incident energies

    International Nuclear Information System (INIS)

    Egelhof, P.

    1997-02-01

    The investigation of light-ion induced direct reactions with exotic beams in inverse kinematics gives access to a wide field of nuclear structure studies in the region far off stability. The present contribution will focus on the investigation of few-nucleon transfer reactions, which turn out to be most favourably studied with good-quality low-energy radioactive beams, as provided by the new generation of radioactive beam facilities presently planned or under construction at Caen, Grenoble, Munich, and elsewhere. An overview on the physics motivation, basically concerning nuclear structure and nuclear astrophysics questions, is given. Of particular interest are the nuclear shell model in the region far off stability, the two-body residual interaction in nuclei, the structure of halo nuclei, as well as the understanding of the r-process scenario. The experimental conditions, along with the experimental concept, for such measurements are discussed with particular emphasis on the kinematical conditions, the observables, as well as the appropriate detection schemes. The concept of a large solid angle TPC ionization chamber as an active target for experiments with low-energy radioactive beams is presented. It turns out to be a highly effective detection scheme, well suited for the present experimental conditions, at least for light exotic beams up to Z∼20. (orig.)

  17. Gender differences associated with rearfoot, midfoot, and forefoot kinematics during running.

    Science.gov (United States)

    Takabayashi, Tomoya; Edama, Mutsuaki; Nakamura, Masatoshi; Nakamura, Emi; Inai, Takuma; Kubo, Masayoshi

    2017-11-01

    Females, as compared with males, have a higher proportion of injuries in the foot region. However, the reason for this gender difference regarding foot injuries remains unclear. This study aimed to investigate gender differences associated with rearfoot, midfoot, and forefoot kinematics during running. Twelve healthy males and 12 females ran on a treadmill. The running speed was set to speed which changes from walking to running. Three-dimensional kinematics of rearfoot, midfoot, and forefoot were collected and compared between males and females. Furthermore, spatiotemporal parameters (speed, cadence, and step length) were measured. In the rearfoot angle, females showed a significantly greater peak value of plantarflexion and range of motion in the sagittal plane as compared with males (effect size (ES) = 1.55 and ES = 1.12, respectively). In the midfoot angle, females showed a significantly greater peak value of dorsiflexion and range of motion in the sagittal plane as compared with males (ES = 1.49 and ES = 1.71, respectively). The forefoot peak angles and ranges of motion were not significantly different between the genders in all three planes. A previous study suggested that a gender-related difference in excessive motions of the lower extremities during running has been suggested as a contributing factor to running injuries. Therefore, the present investigation may provide insight into the reason for the high incidence of foot injuries in females.

  18. Flexible margin kinematics and vortex formation of Aurelia aurita and Robojelly.

    Science.gov (United States)

    Villanueva, Alex; Vlachos, Pavlos; Priya, Shashank

    2014-01-01

    The development of a rowing jellyfish biomimetic robot termed as "Robojelly", has led to the discovery of a passive flexible flap located between the flexion point and bell margin on the Aurelia aurita. A comparative analysis of biomimetic robots showed that the presence of a passive flexible flap results in a significant increase in the swimming performance. In this work we further investigate this concept by developing varying flap geometries and comparing their kinematics with A. aurita. It was shown that the animal flap kinematics can be replicated with high fidelity using a passive structure and a flap with curved and tapered geometry gave the most biomimetic performance. A method for identifying the flap location was established by utilizing the bell curvature and the variation of curvature as a function of time. Flaps of constant cross-section and varying lengths were incorporated on the Robojelly to conduct a systematic study of the starting vortex circulation. Circulation was quantified using velocity field measurements obtained from planar Time Resolved Digital Particle Image Velocimetry (TRDPIV). The starting vortex circulation was scaled using a varying orifice model and a pitching panel model. The varying orifice model which has been traditionally considered as the better representation of jellyfish propulsion did not appear to capture the scaling of the starting vortex. In contrast, the pitching panel representation appeared to better scale the governing flow physics and revealed a strong dependence on the flap kinematics and geometry. The results suggest that an alternative description should be considered for rowing jellyfish propulsion, using a pitching panel method instead of the traditional varying orifice model. Finally, the results show the importance of incorporating the entire bell geometry as a function of time in modeling rowing jellyfish propulsion.

  19. Does Shoe Collar Height Influence Ankle Joint Kinematics and Kinetics in Sagittal Plane Maneuvers?

    Directory of Open Access Journals (Sweden)

    Yang Yang, Ying Fang, Xini Zhang, Junliang He, Weijie Fu

    2017-12-01

    Full Text Available The Objective of the study is to investigate the effects of basketball shoes with different collar heights on ankle kinematics and kinetics and athletic performance in different sagittal plane maneuvers. Twelve participants who wore high-top and low-top basketball shoes (hereafter, HS and LS, respectively performed a weight-bearing dorsiflexion (WB-DF maneuver, drop jumps (DJs, and lay-up jumps (LJs. Their sagittal plane kinematics and ground reaction forces were recorded using the Vicon motion capture system and Kistler force plates simultaneously. Moreover, ankle dorsiflexion and plantarflexion angles, moment, power, stiffness, and jump height were calculated. In the WB-DF test, the peak ankle dorsiflexion angle (p = 0.041 was significantly smaller in HS than in LS. Additionally, the peak ankle plantarflexion moment (p = 0.028 and power (p = 0.022 were significantly lower in HS than in LS during LJs but not during DJs. In both jumping maneuvers, no significant differences were found in the jump height or ankle kinematics between the two shoe types. According to the WB-DF test, increasing shoe collar height can effectively reduce the ankle range of motion in the sagittal plane. Although the HS did not restrict the flexion–extension performance of the ankle joint during two jumping maneuvers, an increased shoe collar height can reduce peak ankle plantarflexion moment and peak power during the push-off phase in LJs. Therefore, a higher shoe collar height should be used to circumvent effects on the partial kinetics of the ankle joint in the sagittal plane.

  20. Understanding the central kinematics of globular clusters with simulated integrated-light IFU observations

    Science.gov (United States)

    Bianchini, Paolo; Norris, Mark A.; van de Ven, Glenn; Schinnerer, Eva

    2015-10-01

    The detection of intermediate-mass black holes in the centres of globular clusters is highly controversial, as complementary observational methods often deliver significantly different results. In order to understand these discrepancies, we develop a procedure to simulate integral field unit (IFU) observations of globular clusters: Simulating IFU Star Cluster Observations (SISCO). The inputs of our software are realistic dynamical models of globular clusters that are then converted in a spectral data cube. We apply SISCO to Monte Carlo cluster simulations with a realistic number of stars and concentrations. Using independent realizations of a given simulation we are able to quantify the stochasticity intrinsic to the problem of observing a partially resolved stellar population with integrated-light spectroscopy. We show that the luminosity-weighted IFU observations can be strongly biased by the presence of a few bright stars that introduce a scatter in the velocity dispersion measurements up to ≃40 per cent around the expected value, preventing any sound assessment of the central kinematic and a sensible interpretation of the presence/absence of an intermediate-mass black hole. Moreover, we illustrate that, in our mock IFU observations, the average kinematic tracer has a mass of ≃0.75 M⊙, only slightly lower than the mass of the typical stars examined in studies of resolved line-of-sight velocities of giant stars. Finally, in order to recover unbiased kinematic measurements we test different masking techniques that allow us to remove the spaxels dominated by bright stars, bringing the scatter down to a level of only a few per cent. The application of SISCO will allow us to investigate state-of-the-art simulations as realistic observations.

  1. Scapula kinematics of pull-up techniques: Avoiding impingement risk with training changes.

    Science.gov (United States)

    Prinold, Joe A I; Bull, Anthony M J

    2016-08-01

    Overhead athletic activities and scapula dyskinesia are linked with shoulder pathology; pull-ups are a common training method for some overhead sports. Different pull-up techniques exist: anecdotally some are easier to perform, and others linked to greater incidences of pathology. This study aims to quantify scapular kinematics and external forces for three pull-up techniques, thus discussing potential injury implications. An observational study was performed with eleven participants (age=26.8±2.4 years) who regularly perform pull-ups. The upward motions of three pull-up techniques were analysed: palms facing anterior, palms facing posterior and wide-grip. A skin-fixed scapula tracking technique with attached retro-reflective markers was used. High intra-participant repeatability was observed: mean coefficients of multiple correlations of 0.87-1.00 in humerothoracic rotations and 0.77-0.90 for scapulothoracic rotations. Standard deviations of hand force was low: kinematics were observed between the pull-up techniques. The reverse technique has extreme glenohumeral internal-external rotation and large deviation from the scapula plane. The wide technique has a reduced range of pro/retraction in the same HT plane of elevation and 90° of arm abduction with 45° external rotation was observed. All these factors suggest increased sub-acromial impingement risk. The scapula tracking technique showed high repeatability. High arm elevation during pull-ups reduces sub-acromial space and increases pressure, increasing the risk of impingement injury. Wide and reverse pull-ups demonstrate kinematics patterns linked with increased impingement risk. Weight-assisted front pull-ups require further investigation and could be recommended for weaker participants. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  2. Flexible margin kinematics and vortex formation of Aurelia aurita and Robojelly.

    Directory of Open Access Journals (Sweden)

    Alex Villanueva

    Full Text Available The development of a rowing jellyfish biomimetic robot termed as "Robojelly", has led to the discovery of a passive flexible flap located between the flexion point and bell margin on the Aurelia aurita. A comparative analysis of biomimetic robots showed that the presence of a passive flexible flap results in a significant increase in the swimming performance. In this work we further investigate this concept by developing varying flap geometries and comparing their kinematics with A. aurita. It was shown that the animal flap kinematics can be replicated with high fidelity using a passive structure and a flap with curved and tapered geometry gave the most biomimetic performance. A method for identifying the flap location was established by utilizing the bell curvature and the variation of curvature as a function of time. Flaps of constant cross-section and varying lengths were incorporated on the Robojelly to conduct a systematic study of the starting vortex circulation. Circulation was quantified using velocity field measurements obtained from planar Time Resolved Digital Particle Image Velocimetry (TRDPIV. The starting vortex circulation was scaled using a varying orifice model and a pitching panel model. The varying orifice model which has been traditionally considered as the better representation of jellyfish propulsion did not appear to capture the scaling of the starting vortex. In contrast, the pitching panel representation appeared to better scale the governing flow physics and revealed a strong dependence on the flap kinematics and geometry. The results suggest that an alternative description should be considered for rowing jellyfish propulsion, using a pitching panel method instead of the traditional varying orifice model. Finally, the results show the importance of incorporating the entire bell geometry as a function of time in modeling rowing jellyfish propulsion.

  3. Distal radius fractures result in alterations in scapular kinematics: a three-dimensional motion analysis.

    Science.gov (United States)

    Ayhan, Cigdem; Turgut, Elif; Baltaci, Gul

    2015-03-01

    Scapular motion is closely integrated with arm motion. Injury to a distal segment requires compensatory changes in the proximal segments leading to alterations in scapular motion. Since the effects of distal injuries on scapular kinematics remain unknown, in the present study we investigated the influences on scapular motion in patients with distal injuries. Sixteen subjects with a history of distal radius fracture and 20 asymptomatic healthy subjects (controls) participated in the study. Three-dimensional scapular and humeral kinematic data were collected on all 3 planes of shoulder elevation: frontal, sagittal, and scapular. All testing was performed in a single session; therefore, the sensors remained attached to the participants for all testing. The position and orientation data of the scapula at 30°, 60°, 90°, and 120° humerothoracic elevation and 120°, 90°, 60°, and 30° lowering were used for statistical comparisons. Independent samples t-test was used to compare the scapular internal/external rotation, upward/downward rotation, and anterior/posterior tilt between the affected side of subjects with a distal radius fracture and the dominant side of asymptomatic subjects at the same stage of humerothoracic elevation. Scapular internal rotation was significantly increased at 30° elevation (P=0.01), 90° elevation (P=0.03), and 30° lowering (P=0.03), and upward rotation was increased at 30° and 60° elevation (Pplane elevation. Scapular upward rotation and anterior tilt were significantly increased during 30° lowering on both the scapular (P=0.002 and 0.02, respectively) and sagittal planes (P=0.01 and 0.02. respectively). Patients with distal radius fractures exhibit altered scapular kinematics, which may further contribute to the development of secondary musculoskeletal pathologies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Introduction to Force-Dependent Kinematics: Theory and Application to Mandible Modeling.

    Science.gov (United States)

    Skipper Andersen, Michael; de Zee, Mark; Damsgaard, Michael; Nolte, Daniel; Rasmussen, John

    2017-09-01

    Knowledge of the muscle, ligament, and joint forces is important when planning orthopedic surgeries. Since these quantities cannot be measured in vivo under normal circumstances, the best alternative is to estimate them using musculoskeletal models. These models typically assume idealized joints, which are sufficient for general investigations but insufficient if the joint in focus is far from an idealized joint. The purpose of this study was to provide the mathematical details of a novel musculoskeletal modeling approach, called force-dependent kinematics (FDK), capable of simultaneously computing muscle, ligament, and joint forces as well as internal joint displacements governed by contact surfaces and ligament structures. The method was implemented into the anybody modeling system and used to develop a subject-specific mandible model, which was compared to a point-on-plane (POP) model and validated against joint kinematics measured with a custom-built brace during unloaded emulated chewing, open and close, and protrusion movements. Generally, both joint models estimated the joint kinematics well with the POP model performing slightly better (root-mean-square-deviation (RMSD) of less than 0.75 mm for the POP model and 1.7 mm for the FDK model). However, substantial differences were observed when comparing the estimated joint forces (RMSD up to 24.7 N), demonstrating the dependency on the joint model. Although the presented mandible model still contains room for improvements, this study shows the capabilities of the FDK methodology for creating joint models that take the geometry and joint elasticity into account.

  5. Does Shoe Collar Height Influence Ankle Joint Kinematics and Kinetics in Sagittal Plane Maneuvers?

    Science.gov (United States)

    Yang, Yang; Fang, Ying; Zhang, Xini; He, Junliang; Fu, Weijie

    2017-12-01

    The Objective of the study is to investigate the effects of basketball shoes with different collar heights on ankle kinematics and kinetics and athletic performance in different sagittal plane maneuvers. Twelve participants who wore high-top and low-top basketball shoes (hereafter, HS and LS, respectively) performed a weight-bearing dorsiflexion (WB-DF) maneuver, drop jumps (DJs), and lay-up jumps (LJs). Their sagittal plane kinematics and ground reaction forces were recorded using the Vicon motion capture system and Kistler force plates simultaneously. Moreover, ankle dorsiflexion and plantarflexion angles, moment, power, stiffness, and jump height were calculated. In the WB-DF test, the peak ankle dorsiflexion angle (p = 0.041) was significantly smaller in HS than in LS. Additionally, the peak ankle plantarflexion moment (p = 0.028) and power (p = 0.022) were significantly lower in HS than in LS during LJs but not during DJs. In both jumping maneuvers, no significant differences were found in the jump height or ankle kinematics between the two shoe types. According to the WB-DF test, increasing shoe collar height can effectively reduce the ankle range of motion in the sagittal plane. Although the HS did not restrict the flexion-extension performance of the ankle joint during two jumping maneuvers, an increased shoe collar height can reduce peak ankle plantarflexion moment and peak power during the push-off phase in LJs. Therefore, a higher shoe collar height should be used to circumvent effects on the partial kinetics of the ankle joint in the sagittal plane.

  6. High-resolution spectroscopy of deeply-bound pionic atoms in heavy nuclei by pion-transfer reactions of inverse kinematics using the GSI cooler ring ESR

    International Nuclear Information System (INIS)

    Yamazaki, Toshimitsu.

    1991-02-01

    Many studies published in the past are reviewed first in relation to high-resolution spectroscopy of deeply-bound pionic atoms in heavy nuclei. The report then describes a procedure for applying the method of inverse kinematics to the case of (d, 3 He) reactions. The (d, 3 He) reaction in inverse kinematics is feasible from practical viewpoints. Thus a discussion is made of the inverse kinematics in which a heavy-ion beam ( 208 Pb for instance) with a projectile kinetic energy hits a deuteron target and ejected recoil 3 He nuclei are measured in the forward direction. The recoil momentum is calculated as a function of the Q value. Analysis shows that the recoil spectroscopy with inverse kinematics can be applied to the case of (d, 3 He) reaction, which will yield a very high mass resolution. The experimental setup for use in the first stage is then outlined, and a simple detector configuration free of magnetic field is discussed. These investigations demonstrate that the (d, 3 He) reaction in inverse kinematics provides a promising tool for obtaining high-resolution spectra of deeply-bound pionic atoms. (N.K.)

  7. A Reactive Balance Rating Method that Correlates with Kinematics after Trip-Like Perturbations on a Treadmill and Fall Risk Among Residents of Older Adult Congregate Housing.

    Science.gov (United States)

    Madigan, Michael L; Aviles, Jessica; Allin, Leigh J; Nussbaum, Maury A; Alexander, Neil B

    2018-04-16

    A growing number of studies are using modified treadmills to train reactive balance after trip-like perturbations that require multiple steps to recover balance. The goal of this study was thus to develop and validate a low-tech reactive balance rating method in the context of trip-like treadmill perturbations to facilitate the implementation of this training outside the research setting. Thirty-five residents of five senior congregate housing facilities participated in the study. Subjects completed a series of reactive balance tests on a modified treadmill from which the reactive balance rating was determined, along with a battery of standard clinical balance and mobility tests that predict fall risk. We investigated the strength of correlation between the reactive balance rating and reactive balance kinematics. We compared the strength of correlation between the reactive balance rating and clinical tests predictive of fall risk, with the strength of correlation between reactive balance kinematics and the same clinical tests. We also compared the reactive balance rating between subjects predicted to be at a high or low risk of falling. The reactive balance rating was correlated with reactive balance kinematics (Spearman's rho squared = .04 - .30), exhibited stronger correlations with clinical tests than most kinematic measures (Spearman's rho squared = .00 - .23), and was 42-60% lower among subjects predicted to be at a high risk for falling. The reactive balance rating method may provide a low-tech, valid measure of reactive balance kinematics, and an indicator of fall risk, after trip-like postural perturbations.

  8. Study on lumbar kinematics and the risk of low back disorder in female university students by using shoes of different heel heights.

    Science.gov (United States)

    Iqbal, Rauf; De, Amitabha; Mishra, Wricha; Maulik, Shreya; Chandra, A M

    2012-01-01

    The study was taken up to investigate the effects of heel heights on lumbar kinematics and the risk of Low Back Disorder (LBD) in females. Nineteen female university students (24.5 ± 3.36 yrs) volunteered in the study. Lumbar kinematics was measured by using Industrial Lumbar Motion Monitor (iLMM). The volunteers were asked to walk for a distance of 50 meters in 3 different given conditions i.e bare foot (Heel 0), with flat heels (Heel 1) and with high heels (Heel 2). Heights of Heel 1 and Heel 2 were 1.5 ± 0.84 cm and 5.5 ± 1.70 cm respectively. The Lumbar kinematic parameters studied were- Average Twisting Velocity (ATV), Maximum Sagital Flexion (MSF) and Maximum Lateral Velocity (MLV). It was observed that all the above mentioned Lumbar kinematics - ATV, MSF and MLV increases with increase of heel heights, which in turn increases the risk of LBD. As a result of increase in Lumbar kinematic values with increase in heel heights, LBD risk has also increased. Mean and SD of the LBD risk with Heel 0, Heel 1 and Heel 2 were 16.79 ± 6.04%, 19.00 ± 7.38% and 22.11 ± 6.98% respectively. Lower stature with high heels showed higher risk of LBD than the higher stature with high heels.

  9. Kinematic alterations of the lower limbs and pelvis during an ascending stairs task are associated with the degree of knee osteoarthritis severity.

    Science.gov (United States)

    Gonçalves, Glaucia Helena; Selistre, Luiz Fernando Approbato; Petrella, Marina; Mattiello, Stela Márcia

    2017-03-01

    Individuals with knee osteoarthritis (OA) generally demonstrate great difficulty in ascending stairs. The strategies and compensations used by these individuals in stair activities have not been fully established. The purpose of this study was to investigate the joint kinematics of the pelvis, hip, knee and ankle throughout the gait cycle, in the sagittal and frontal planes, in individuals with mild and moderate knee OA, during an ascending stairs task. Thirty-one individuals with knee OA and 19 controls were subjected to clinical and radiographic analysis, divided into three groups: control, mild knee OA, and moderate knee OA. Participants answered a self-reported questionnaire, carried out performance-based tests, and their kinematic data were recorded during an ascending stairs task using an eight-camera Qualisys 3D-Motion analysis system. The individuals with moderate degrees of knee OA demonstrated kinematic alterations in the pelvis, hip, knee, and ankle in the sagittal plane. The individuals with mild degrees of knee OA demonstrated kinematic alterations of the hip in the frontal plane, and kinematic alterations of the ankle in the sagittal plane. The ascending stairs task allowed verification of meaningful information regarding gait strategies used by individuals with mild and moderate knee OA. The strategies of these two groups of individuals are different for this task, although more pronounced in individuals with moderate knee OA. The findings should be taken into account in the development of rehabilitation programs. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Decoupled Closed-Form Solution for Humanoid Lower Limb Kinematics

    Directory of Open Access Journals (Sweden)

    Alejandro Said

    2015-01-01

    Full Text Available This paper presents an explicit, omnidirectional, analytical, and decoupled closed-form solution for the lower limb kinematics of the humanoid robot NAO. The paper starts by decoupling the position and orientation analysis from the overall Denavit-Hartenberg (DH transformation matrices. Here, the joint activation sequence for the DH matrices is based on the geometry of a triangle. Furthermore, the implementation of a forward and a reversed kinematic analysis for the support and swing phase equations is developed to avoid matrix inversion. The allocation of constant transformations allows the position and orientation end-coordinate systems to be aligned with each other. Also, the redefinition of the DH transformations and the use of constraints allow decoupling the shared DOF between the legs and the torso. Finally, a geometric approach to avoid the singularities during the walking process is indicated. Numerical data is presented along with an experimental implementation to prove the validity of the analytical results.

  11. [Advances on biomechanics and kinematics of sprain of ankle joint].

    Science.gov (United States)

    Zhao, Yong; Wang, Gang

    2015-04-01

    Ankle sprains are orthopedic clinical common disease, accounting for joint ligament sprain of the first place. If treatment is not timely or appropriate, the joint pain and instability maybe develop, and even bone arthritis maybe develop. The mechanism of injury of ankle joint, anatomical basis has been fully study at present, and the diagnostic problem is very clear. Along with the development of science and technology, biological modeling and three-dimensional finite element, three-dimensional motion capture system,digital technology study, electromyographic signal study were used for the basic research of sprain of ankle. Biomechanical and kinematic study of ankle sprain has received adequate attention, combined with the mechanism research of ankle sprain,and to explore the the biomechanics and kinematics research progress of the sprain of ankle joint.

  12. A School Experiment in Kinematics: Shooting from a Ballistic Cart

    Science.gov (United States)

    Kranjc, T.; Razpet, N.

    2011-10-01

    Many physics textbooks start with kinematics. In the lab, students observe the motions, describe and make predictions, and get acquainted with basic kinematics quantities and their meaning. Then they can perform calculations and compare the results with experimental findings. In this paper we describe an experiment that is not often done, but is interesting and attractive to students—the ballistic cart, i.e., the shooting of a ball from a cart moving along a slope. For that, one has to be familiar with one-dimensional uniform motion and one-dimensional motion with constant acceleration, as well as curvilinear motion that is a combination of such motions.1,2 The experimental results confirm theoretical predictions.

  13. A novel mechanism for emulating insect wing kinematics

    International Nuclear Information System (INIS)

    Seshadri, Pranay; Benedict, Moble; Chopra, Inderjit

    2012-01-01

    A novel dual-differential four-bar flapping mechanism that can accurately emulate insect wing kinematics in all three degrees of freedom (translation, rotation and stroke plane deviation) is developed. The mechanism is specifically designed to be simple and scalable such that it can be utilized on an insect-based flapping wing micro air vehicle. Kinematic formulations for the wing stroke position, pitch angle and coning angle for this model are derived from first principles and compared with a 3D simulation. A benchtop flapping mechanism based on this model was designed and built, which was also equipped with a balance for force measurements. 3D motion capture tests were conducted on this setup to demonstrate the capability of generating complex figure-of-eight flapping motions along with dynamic pitching. The dual-differential four-bar mechanism was implemented on a light-weight vehicle that demonstrated tethered hover. (paper)

  14. Invariant length scale in relativistic kinematics: lessons from Dirichlet branes

    International Nuclear Information System (INIS)

    Schuller, Frederic P.; Pfeiffer, Hendryk

    2004-01-01

    Dirac-Born-Infeld theory is shown to possess a hidden invariance associated with its maximal electric field strength. The local Lorentz symmetry O(1,n) on a Dirichlet-n-brane is thereby enhanced to an O(1,n)xO(1,n) gauge group, encoding both an invariant velocity and acceleration (or length) scale. The presence of this enlarged gauge group predicts consequences for the kinematics of observers on Dirichlet branes, with admissible accelerations being bounded from above. An important lesson is that the introduction of a fundamental length scale into relativistic kinematics does not enforce a deformation of Lorentz boosts, as one might assume naively. The exhibited structures further show that Moffat's non-symmetric gravitational theory qualifies as a candidate for a consistent Born-Infeld type gravity with regulated solutions

  15. D2 Delta Robot Structural Design and Kinematics Analysis

    Science.gov (United States)

    Yang, Xudong; wang, Song; Dong, Yu; Yang, Hai

    2017-12-01

    In this paper, a new type of Delta robot with only two degrees of freedom is proposed on the basis of multi - degree - of - freedom delta robot. In order to meet our application requirements, we have carried out structural design and analysis of the robot. Through SolidWorks modeling, combined with 3D printing technology to determine the final robot structure. In order to achieve the precise control of the robot, the kinematics analysis of the robot was carried out. The SimMechanics toolbox of MATLAB is used to establish the mechanism model, and the kinematics mathematical model is used to simulate the robot motion control in Matlab environment. Finally, according to the design mechanism, the working space of the robot is drawn by the graphic method, which lays the foundation for the motion control of the subsequent robot.

  16. Kinematic MR imaging of the knee for evaluating patellar tracking

    International Nuclear Information System (INIS)

    Shellock, F.G.; Mink, J.H.; Fox, J.

    1988-01-01

    A new technique to evaluate patellar tracking uses MR imaging and a specially designed positioning device (MEDRAD). T1-weighted, axial plane imaging was performed on both knees at the following joint angles: 0 0 , 5 0 , 10 0 , 15 0 , 20 0 , 25 0 , and 30 0 . The total examination time was approximately 12 minutes. Images were viewed in a cine loop to produce a kinematic study that depicted the relationship of the patella to the trochlear groove during the different angles of knee flexion. To date, 102 subjects (204 knees) have been examined. Dislocation, subluxatino, lateral tilt, lateral and medial displacement of the patella, and normal patellar tracking could all be identified with this technique. Abnormal configurations of the patella and/or trochlear groove were also clearly demonstrated. In conclusion, kinematic MR imaging of the knee provided important clinical information concerning patellar tracking and other related abnormalities of the patellofemoral joint

  17. On use of radial evanescence remain term in kinematic hardening

    International Nuclear Information System (INIS)

    Geyer, P.

    1995-01-01

    This paper presents the interest which lies in non-linear kinematic hardening rule with radial evanescence remain term as proposed for modelling multiaxial ratchetting. From analytical calculations in the case of the tension/torsion test, this ratchetting is compared with that proposed by Armstrong and Frederick. A modification is then proposed for Chaboche's elastoplastic model with two non-linear kinematic variables, by coupling the two types of hardening by means of two scalar parameters. Identification of these two parameters returns to speculate on the directions of strain in order to adjust the ratchetting to experimental observations. Using biaxial ratchetting tests on stainless steel 316 L specimens at ambient temperature, it is shown that satisfactory modelling of multiaxial ratchetting is obtained. (author). 4 refs., 5 figs

  18. Kinematical Compatibility Conditions for Vorticity Across Shock Waves

    Science.gov (United States)

    Baty, Roy

    2015-11-01

    This work develops the general kinematical compatibility conditions for vorticity across arbitrary shock waves in compressible, inviscid fluids. The vorticity compatibility conditions are derived from the curl of the momentum equation using singular distributions defined on two-dimensional shock wave surfaces embedded in three-dimensional flow fields. The singular distributions are represented as generalized differential operators concentrated on moving shock wave surfaces. The derivation of the compatibility conditions for vorticity requires the application of second-order generalized derivatives and elementary tensor algebra. The well-known vorticity jump conditions across a shock wave are then shown to follow from the general kinematical compatibility conditions for vorticity by expressing the flow field velocity in vectorial components normal and tangential to a shock surface.

  19. Kinematic method for beam energy determination at electrostatic generators

    International Nuclear Information System (INIS)

    Thomas, H.J.; Gersch, H.U.; Hentschel, E.; Wohlfahrt, D.

    1975-06-01

    The applicability of the kinematics of nuclear reactions to the energy determination of a particle beam is discussed. Most favourable conditions are obtained for the kinematic cross over of particles elastically and inelastically scattered at targets with different masses. At tandem energies between 4 and 15 MeV this method permits an exact determination with a precision of about 1 keV. The scattered particles must be measured at about 170 0 with a precision of the scattering angle of 0.1 0 . For the energy determination of a proton beam the compounds LiF, LiCl, or deuterium enriched hydrocarbons are found to be proper target materials. Experimental results with a LiF-target are described. (author)

  20. New Methods for Kinematic Modelling and Calibration of Robots

    DEFF Research Database (Denmark)

    Søe-Knudsen, Rune

    2014-01-01

    the accuracy in an easy and accessible way. The required equipment is accessible, since the cost is held to a minimum and can be made with conventional processing equipment. Our first method calibrates the kinematics of a robot using known relative positions measured with the robot itself and a plate...... with holes matching the robot tool flange. The second method calibrates the kinematics using two robots. This method allows the robots to carry out the collection of measurements and the adjustment, by themselves, after the robots have been connected. Furthermore, we also propose a method for restoring......Improving a robot's accuracy increases its ability to solve certain tasks, and is therefore valuable. Practical ways of achieving this improved accuracy, even after robot repair, is also valuable. In this work, we introduce methods that improve the robot's accuracy and make it possible to maintain...

  1. The kinematic footprints of five stellar streams in Andromeda's halo

    Science.gov (United States)

    Chapman, S. C.; Ibata, R.; Irwin, M.; Koch, A.; Letarte, B.; Martin, N.; Collins, M.; Lewis, G. F.; McConnachie, A.; Peñarrubia, J.; Rich, R. M.; Trethewey, D.; Ferguson, A.; Huxor, A.; Tanvir, N.

    2008-11-01

    We present a spectroscopic analysis of five stellar streams (`A', `B', `Cr', `Cp' and `D') as well as the extended star cluster, EC4, which lies within Stream`C', all discovered in the halo of M31 from our Canada-France-Hawaii Telescope/MegaCam survey. These spectroscopic results were initially serendipitous, making use of our existing observations from the DEep Imaging Multi-Object Spectrograph mounted on the Keck II telescope, and thereby emphasizing the ubiquity of tidal streams that account for ~70 per cent of the M31 halo stars in the targeted fields. Subsequent spectroscopy was then procured in Stream`C' and Stream`D' to trace the velocity gradient along the streams. Nine metal-rich ([Fe/H] ~ -0.7) stars at vhel = -349.5kms-1,σv,corr ~ 5.1 +/- 2.5km s-1 are proposed as a serendipitous detection of Stream`Cr', with follow-up kinematic identification at a further point along the stream. Seven metal-poor ([Fe/H] ~-1.3) stars confined to a narrow, 15 km s-1 velocity bin centred at vhel = -285.6, σv,corr = 4.3+1.7-1.4 km s-1 represent a kinematic detection of Stream`Cp', again with follow-up kinematic identification further along the stream. For the cluster EC4, candidate member stars with average [Fe/H] ~-1.4, are found at vhel = -282 suggesting it could be related to Stream`Cp'. No similarly obvious cold kinematic candidate is found for Stream`D', although candidates are proposed in both of two spectroscopic pointings along the stream (both at ~ -400km s-1). Spectroscopy near the edge of Stream`B' suggests a likely kinematic detection at vhel ~ -330, σv,corr ~ 6.9km s-1, while a candidate kinematic detection of Stream`A' is found (plausibly associated to M33 rather than M31) with vhel ~ -170, σv,corr = 12.5km s-1. The low dispersion of the streams in kinematics, physical thickness and metallicity makes it hard to reconcile with a scenario whereby these stream structures as an ensemble are related to the giant southern stream. We conclude that the M31 stellar

  2. VRACK: measuring pedal kinematics during stationary bike cycling.

    Science.gov (United States)

    Farjadian, Amir B; Kong, Qingchao; Gade, Venkata K; Deutsch, Judith E; Mavroidis, Constantinos

    2013-06-01

    Ankle impairment and lower limb asymmetries in strength and coordination are common symptoms for individuals with selected musculoskeletal and neurological impairments. The virtual reality augmented cycling kit (VRACK) was designed as a compact mechatronics system for lower limb and mobility rehabilitation. The system measures interaction forces and cardiac activity during cycling in a virtual environment. The kinematics measurement was added to the system. Due to the constrained problem definition, the combination of inertial measurement unit (IMU) and Kalman filtering was recruited to compute the optimal pedal angular displacement during dynamic cycling exercise. Using a novel benchmarking method the accuracy of IMU-based kinematics measurement was evaluated. Relatively accurate angular measurements were achieved. The enhanced VRACK system can serve as a rehabilitation device to monitor biomechanical and physiological variables during cycling on a stationary bike.

  3. Analytic structure of the n=7 scattering amplitude in N=4 SYM theory at multi-Regge kinematics. Conformal Regge pole contribution

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, Jochen; Kormilitzin, Andrey [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Lipatov, Lev [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; St. Petersburg Nuclear Physics Institute, St. Petersburg (Russian Federation)

    2013-11-15

    We investigate the analytic structure of the 2 {yields} 5 scattering amplitude in the planar limit of N=4 SYM in multi-Regge kinematics in all physical regions. We demonstrate the close connection between Regge pole and Regge cut contributions: in a selected class of kinematic regions (Mandelstam regions) the usual factorizing Regge pole formula develops unphysical singularities which have to be absorbed and compensated by Regge cut contributions. This leads, in the corrections to the BDS formula, to conformal invariant 'renormalized' Regge pole expressions in the remainder function. We compute these renormalized Regge poles for the 2 {yields} 5 scattering amplitude.

  4. Development of Kinematic Graphs of Median Nerve during Active Finger Motion: Implications of Smartphone Use.

    Directory of Open Access Journals (Sweden)

    Hoi-Chi Woo

    Full Text Available Certain hand activities cause deformation and displacement of the median nerve at the carpal tunnel due to the gliding motion of tendons surrounding it. As smartphone usage escalates, this raises the public's concern whether hand activities while using smartphones can lead to median nerve problems.The aims of this study were to 1 develop kinematic graphs and 2 investigate the associated deformation and rotational information of median nerve in the carpal tunnel during hand activities.Dominant wrists of 30 young adults were examined with ultrasonography by placing a transducer transversely on their wrist crease. Ultrasound video clips were recorded when the subject performing 1 thumb opposition with the wrist in neutral position, 2 thumb opposition with the wrist in ulnar deviation and 3 pinch grip with the wrist in neutral position. Six still images that were separated by 0.2-second intervals were then captured from the ultrasound video for the determination of 1 cross-sectional area (CSA, 2 flattening ratio (FR, 3 rotational displacement (RD and 4 translational displacement (TD of median nerve in the carpal tunnel, and these collected information of deformation, rotational and displacement of median nerve were compared between 1 two successive time points during a single hand activity and 2 different hand motions at the same time point. Finally, kinematic graphs were constructed to demonstrate the mobility of median nerve during different hand activities.Performing different hand activities during this study led to a gradual reduction in CSA of the median nerve, with thumb opposition together with the wrist in ulnar deviation causing the greatest extent of deformation of the median nerve. Thumb opposition with the wrist in ulnar deviation also led to the largest extent of TD when compared to the other two hand activities of this study. Kinematic graphs showed that the motion pathways of median nerve during different hand activities were complex

  5. Kinematic control of aerodynamic forces on an inclined flapping wing with asymmetric strokes

    International Nuclear Information System (INIS)

    Park, Hyungmin; Choi, Haecheon

    2012-01-01

    In the present study, we conduct an experiment using a one-paired dynamically scaled model of an insect wing, to investigate how asymmetric strokes with different wing kinematic parameters are used to control the aerodynamics of a dragonfly-like inclined flapping wing in still fluid. The kinematic parameters considered are the angles of attack during the mid-downstroke (α md ) and mid-upstroke (α mu ), and the duration (Δτ) and time of initiation (τ p ) of the pitching rotation. The present dragonfly-like inclined flapping wing has the aerodynamic mechanism of unsteady force generation similar to those of other insect wings in a horizontal stroke plane, but the detailed effect of the wing kinematics on the force control is different due to the asymmetric use of the angle of attack during the up- and downstrokes. For example, high α md and low α mu produces larger vertical force with less aerodynamic power, and low α md and high α mu is recommended for horizontal force (thrust) production. The pitching rotation also affects the aerodynamics of a flapping wing, but its dynamic rotational effect is much weaker than the effect from the kinematic change in the angle of attack caused by the pitching rotation. Thus, the influences of the duration and timing of pitching rotation for the present inclined flapping wing are found to be very different from those for a horizontal flapping wing. That is, for the inclined flapping motion, the advanced and delayed rotations produce smaller vertical forces than the symmetric one and the effect of pitching duration is very small. On the other hand, for a specific range of pitching rotation timing, delayed rotation requires less aerodynamic power than the symmetric rotation. As for the horizontal force, delayed rotation with low α md and high α mu is recommended for long-duration flight owing to its high efficiency, and advanced rotation should be employed for hovering flight for nearly zero horizontal force. The present

  6. Dwarf galaxy dark matter density profiles inferred from stellar and gas kinematics

    International Nuclear Information System (INIS)

    Adams, Joshua J.; Simon, Joshua D.; Fabricius, Maximilian H.; Bender, Ralf; Thomas, Jens; Van den Bosch, Remco C. E.; Van de Ven, Glenn; Barentine, John C.; Gebhardt, Karl; Hill, Gary J.; Murphy, Jeremy D.; Swaters, R. A.

    2014-01-01

    We present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. The gas kinematics of low-mass galaxies frequently suggest that they contain constant density DM cores, while N-body simulations instead predict a cuspy profile. We present a data set of high-resolution integral-field spectroscopy on seven galaxies and measure the stellar and gas kinematics simultaneously. Using Jeans modeling on our full sample, we examine whether gas kinematics in general produce shallower density profiles than are derived from the stars. Although two of the seven galaxies show some localized differences in their rotation curves between the two tracers, estimates of the central logarithmic slope of the DM density profile, γ, are generally robust. The mean and standard deviation of the logarithmic slope for the population are γ = 0.67 ± 0.10 when measured in the stars and γ = 0.58 ± 0.24 when measured in the gas. We also find that the halos are not under-concentrated at the radii of half their maximum velocities. Finally, we search for correlations of the DM density profile with stellar velocity anisotropy and other baryonic properties. Two popular mechanisms to explain cored DM halos are an exotic DM component or feedback models that strongly couple the energy of supernovae into repeatedly driving out gas and dynamically heating the DM halos. While such models do not yet have falsifiable predictions that we can measure, we investigate correlations that may eventually be used to test models. We do not find a secondary parameter that strongly correlates with the central DM density slope, but we do find some weak correlations. The central DM density slope weakly correlates with the abundance of α elements in the stellar population, anti-correlates with H I fraction, and anti-correlates with vertical orbital anisotropy. We expect, if anything, the opposite of these

  7. Structural Brain Damage and Upper Limb Kinematics in Children with Unilateral Cerebral Palsy

    Directory of Open Access Journals (Sweden)

    Lisa Mailleux

    2017-12-01

    Full Text Available Background: In children with unilateral cerebral palsy (uCP virtually nothing is known on the relation between structural brain damage and upper limb (UL kinematics quantified with three-dimensional movement analysis (3DMA. This explorative study aimed to (1 investigate differences in UL kinematics between children with different lesion timings, i.e., periventricular white matter (PWM vs. cortical and deep gray matter (CDGM lesions and (2 to explore the relation between UL kinematics and lesion location and extent within each lesion timing group.Methods: Forty-eight children (age 10.4 ± 2.7 year; 29 boys; 21 right-sided; 33 PWM; 15 CDGM underwent an UL 3DMA during a reach-to-grasp task. Spatiotemporal parameters [movement duration, (timing of maximum velocity, trajectory straightness], the Arm Profile Score (APS and Arm Variable Scores (AVS were extracted. The APS and AVS refer to the total amount of movement pathology and movement deviations of the wrist, elbow, shoulder, scapula and trunk respectively. Brain lesion location and extent were scored based on FLAIR-images using a semi-quantitative MRI-scale.Results: Children with CDGM lesions showed more aberrant spatiotemporal parameters (p < 0.03 and more movement pathology (APS, p = 0.003 compared to the PWM group, mostly characterized by increased wrist flexion (p = 0.01. In the CDGM group, moderate to high correlations were found between lesion location and extent and duration, timing of maximum velocity and trajectory straightness (r = 0.53–0.90. Lesion location and extent were further moderately correlated with distal UL movement pathology (wrist flexion/extension, elbow pronation/supination, elbow flexion/extension; r = 0.50–0.65 and with the APS (r = 0.51–0.63. In the PWM group, only a few and low correlations were observed, mostly between damage to the PLIC and higher AVS of elbow flexion/extension, shoulder elevation and trunk rotation (r = 0.35–0.42. Regression analysis

  8. Manipulation of the kinematic chain using visual biofeedback

    OpenAIRE

    Mulloy, Franky; Mullineaux, David; Irwin, Gareth

    2016-01-01

    Feedback has been shown to be an influential component in skill development, yet this has not been assessed in movements involving an explosive proximal to distal sequencing pattern. Novices (n=14) were introduced to a lunge touch task. Visual biofeedback were given on the timing and magnitude of rear leg kinematics. Results showed that those who received feedback adapted their movement patterns by developing extension velocity magnitudes in a summative pattern (pre v post, mean ± SD peak ank...

  9. Ionised gas kinematics in bipolar H II regions

    Science.gov (United States)

    Dalgleish, Hannah S.; Longmore, Steven N.; Peters, Thomas; Henshaw, Jonathan D.; Veitch-Michaelis, Joshua L.; Urquhart, James S.

    2018-05-01

    Stellar feedback plays a fundamental role in shaping the evolution of galaxies. Here we explore the use of ionised gas kinematics in young, bipolar H II regions as a probe of early feedback in these star-forming environments. We have undertaken a multi-wavelength study of a young, bipolar H II region in the Galactic disc, G316.81-0.06, which lies at the centre of a massive (˜103 M⊙) infrared-dark cloud filament. It is still accreting molecular gas as well as driving a ˜0.2 pc ionised gas outflow perpendicular to the filament. Intriguingly, we observe a large velocity gradient (47.81 ± 3.21 km s-1 pc-1) across the ionised gas in a direction perpendicular to the outflow. This kinematic signature of the ionised gas shows a reasonable correspondence with the simulations of young H II regions. Based on a qualitative comparison between our observations and these simulations, we put forward a possible explanation for the velocity gradients observed in G316.81-0.06. If the velocity gradient perpendicular to the outflow is caused by rotation of the ionised gas, then we infer that this rotation is a direct result of the initial net angular momentum in the natal molecular cloud. If this explanation is correct, this kinematic signature should be common in other young (bipolar) H II regions. We suggest that further quantitative analysis of the ionised gas kinematics of young H II regions, combined with additional simulations, should improve our understanding of feedback at these early stages.

  10. The broad line region of AGN: Kinematics and physics

    Directory of Open Access Journals (Sweden)

    Popović L.Č.

    2006-01-01

    Full Text Available In this paper a discussion of kinematics and physics of the Broad Line Region (BLR is given. The possible physical conditions in the BLR and problems in determination of the physical parameters (electron temperature and density are considered. Moreover, one analyses the geometry of the BLR and the probability that (at least a fraction of the radiation in the Broad Emission Lines (BELs originates from a relativistic accretion disk.

  11. Raynal–Revai coefficients for a general kinematic rotation

    International Nuclear Information System (INIS)

    Ershov, S. N.

    2016-01-01

    In a three-body system, transitions between different sets of normalized Jacobi coordinates are described as general kinematic transformations that include an orthogonal or a pseudoorthogonal rotation. For such rotations, the Raynal–Revai coefficients execute a unitary transformation between three-body hyperspherical functions. Recurrence relations that make it possible to calculate the Raynal–Revai coefficients for arbitrary angular momenta are derived on the basis of linearized representations of products of hyperspherical functions.

  12. From movement kinematics to social cognition: the case of autism

    Science.gov (United States)

    2016-01-01

    The way in which we move influences our ability to perceive, interpret and predict the actions of others. Thus movements play an important role in social cognition. This review article will appraise the literature concerning movement kinematics and motor control in individuals with autism, and will argue that movement differences between typical and autistic individuals may contribute to bilateral difficulties in reciprocal social cognition. PMID:27069049

  13. Interactive scan control for kinematic study in open MRI

    International Nuclear Information System (INIS)

    Goto, Tomohiro; Hamada, Kiyomi; Ito, Taeko; Nagao, Hisako; Takahashi, Tetsuhiko; Hayashida, Yoshiko; Hiai, Yasuhiro; Yamashita, Yasuyuki

    2007-01-01

    A tool to support the subject is generally used for kinematic joint imaging with an open MRI apparatus because of difficulty setting the image plane correctly. However, use of a support tool requires a complicated procedure to position the subject, and setting the image plane when the joint angle changes is time consuming. Allowing the subject to move freely enables better diagnoses when kinematic joint imaging is performed. We therefore developed an interactive scan control (ISC) to facilitate the easy, quick, and accurate setting of the image plane even when a support tool is not used. We used a 0.4T magnetic resonance (MR) imaging system open in the horizontal direction. The ISC determines the image plane interactively on the basis of fluoroscopy images displayed on a user interface. The imaging pulse is a balanced steady-state acquisition with rewound gradient echo (SARGE) sequence with update time less than 2 s. Without using a tool to support the knee, we positioned the knee of a healthy volunteer at 4 different joint angles and set the image plane through the patella and femur at each of the angles. Lumbar imaging is also demonstrated with ISC. Setting the image plane was easy and quick at all knee angles, and images obtained clearly showed the patella and femur. Total imaging time was less than 10 min, a fourth of the time needed when a support tool is used. We also used our ISC in kinematic imaging of the lumbar. The ISC shortens total time for kinematic joint imaging, and because a support tool is not needed, imaging can be done more freely in an open MR imaging apparatus. (author)

  14. Modeling aspects of wave kinematics in offshore structures dynamics

    International Nuclear Information System (INIS)

    Spanos, P.D.; Ghanem, R.; Bhattacharjee, S.

    1993-01-01

    Magnitude and phase related issues of modeling of ocean wave kinematics are addressed. Causal and non-causal filters are examined. It is shown that if for a particular ocean engineering problem only the magnitude representation of wave spectra spatial relation is critical, analog filters can be quite useful models in conjunction with the technique of statistical linearization, for calculating dynamic analyses. This is illustrated by considering the dynamic response of a simple model of a guyed tower

  15. On the kinematics of the two-photon Cherenkov effect

    International Nuclear Information System (INIS)

    Afanas'ev, G.N.; Stepanovskij, Yu.P.

    2003-01-01

    We study the kinematics of the two-photon Cherenkov effect. In the general case, the emission angles of two photons satisfy certain inequalities and the corresponding radiation intensities are rather diffused. In special cases, when the above inequalities reduce to equalities, the emission angles of two photons are fixed and the corresponding radiation intensities should have sharp maxima at these angles. This makes easier the experimental study of the two-photon Cherenkov effect

  16. Kinematic and ground reaction force accommodation during weighted walking.

    Science.gov (United States)

    James, C Roger; Atkins, Lee T; Yang, Hyung Suk; Dufek, Janet S; Bates, Barry T

    2015-12-01

    Weighted walking is a functional activity common in daily life and can influence risks for musculoskeletal loading, injury and falling. Much information exists about weighted walking during military, occupational and recreational tasks, but less is known about strategies used to accommodate to weight carriage typical in daily life. The purposes of the study were to examine the effects of weight carriage on kinematics and peak ground reaction force (GRF) during walking, and explore relationships between these variables. Twenty subjects walked on a treadmill while carrying 0, 44.5 and 89 N weights in front of the body. Peak GRF, sagittal plane joint/segment angular kinematics, stride length and center of mass (COM) vertical displacement were measured. Changes in peak GRF and displacement variables between weight conditions represented accommodation. Effects of weight carriage were tested using analysis of variance. Relationships between peak GRF and kinematic accommodation variables were examined using correlation and regression. Subjects were classified into sub-groups based on peak GRF responses and the correlation analysis was repeated. Weight carriage increased peak GRF by an amount greater than the weight carried, decreased stride length, increased vertical COM displacement, and resulted in a more extended and upright posture, with less hip and trunk displacement during weight acceptance. A GRF increase was associated with decreases in hip extension (|r|=.53, p=.020) and thigh anterior rotation (|r|=.57, p=.009) displacements, and an increase in foot anterior rotation displacement (|r|=.58, p=.008). Sub-group analysis revealed that greater GRF increases were associated with changes at multiple sites, while lesser GRF increases were associated with changes in foot and trunk displacement. Weight carriage affected walking kinematics and revealed different accommodation strategies that could have implications for loading and stability. Copyright © 2015 Elsevier B

  17. Kinematics changes in technique of a softball pitch

    OpenAIRE

    Tomášek, Petr

    2007-01-01

    Headline: Kinematic changes in technique of a softball pitch. Aims of thesis: I will compare the pitches ofprofessinal european softball wonam pitchers and then I will compare their technique with professional czech woman pitcher. Methods: Results: Key words: For examination of different techniques, I choosed thease professinal european softball wonam pitchers 3 Italians and 2 Greeks. Videotape was taken on European championship 2005 in Prague. For description of softball pitch I used a metho...

  18. Kinematic and Kinetic Evaluation of High Speed Backward Running

    Science.gov (United States)

    1999-06-30

    Designed using Perform Pro , WHS/DIOR, Oct 94 KINEMATIC AND KINETIC EVALUATION OF HIGH SPEED BACKWARD RUNNING by ALAN WAYNE ARATA A DISSERTATION...Project Manager, Engineering Division, Kelly Air Force Base, Texas, 1983-86 AWARDS AND HONORS: All-American, 50yd Freestyle , 1979 Winner, Rocky...redirection #include <stdlib.h> // for exit #include <iomanip.h> // for set precision #include <string.h> // for string copy const int NUMPOINTS

  19. Production of radioactive nuclides in inverse reaction kinematics

    International Nuclear Information System (INIS)

    Traykov, E.; Rogachevskiy, A.; Bosswell, M.; Dammalapati, U.; Dendooven, P.; Dermois, O.C.; Jungmann, K.; Onderwater, C.J.G.; Sohani, M.; Willmann, L.; Wilschut, H.W.; Young, A.R.

    2007-01-01

    Efficient production of short-lived radioactive isotopes in inverse reaction kinematics is an important technique for various applications. It is particularly relevant when the isotope of interest is only a few nucleons away from a stable isotope. In this article production via charge exchange and stripping reactions in combination with a magnetic separator is explored. The relation between the separator transmission efficiency, the production yield, and the choice of beam energy is discussed. The results of some exploratory experiments will be presented

  20. A kinematic fit method for all-photon events

    International Nuclear Information System (INIS)

    Du Shuxian; Yuan Changzheng; Chinese Academy of Sciences, Beijing

    2006-01-01

    An improved kinematic fit method is developed for analyzing all-photon events, where the interaction point is unknown. The fitting algorithm is checked with Monte Carlo samples to ensure that the fitting program works properly. This is applied to the Monte Carlo simulated ψ(2S) decays. A higher efficiency is achieved. This method can be generally applied to analyzing all-photon events at electron-positron collider. (authors)

  1. Dancers with achilles tendinopathy demonstrate altered lower extremity takeoff kinematics.

    Science.gov (United States)

    Kulig, Kornelia; Loudon, Janice K; Popovich, John M; Pollard, Christine D; Winder, Brooke R

    2011-08-01

    Controlled laboratory study using a cross-sectional design. To analyze lower extremity kinematics during takeoff of a "saut de chat" (leap) in dancers with and without a history of Achilles tendinopathy (AT). We hypothesized that dancers with AT would demonstrate different kinematic strategies compared to dancers without pathology, and that these differences would be prominent in the transverse and frontal planes. AT is a common injury experienced by dancers. Dance leaps such as the saut de chat place a large demand on the Achilles tendon. Sixteen female dancers with and without a history of AT (mean ± SD age, 18.8 ± 1.2 years) participated. Three-dimensional kinematics at the hip, knee, and ankle were quantified for the takeoff of the saut de chat, using a motion analysis system. A force platform was used to determine braking and push-off phases of takeoff. Peak sagittal, frontal, and transverse plane joint positions during the braking and push-off phases of the takeoff were examined statistically. Independent samples t tests were used to evaluate group differences (α = .05). The dancers in the tendinopathy group demonstrated significantly higher peak hip adduction during the braking phase of takeoff (mean ± SD, 13.5° ± 6.1° versus 7.7° ± 4.2°; P = .046). During the push-off phase, dancers with AT demonstrated significantly more internal rotation at the knee (13.2° ± 5.2° versus 6.9° ± 4.9°; P = .024). Dancers with AT demonstrate increased peak transverse and frontal plane kinematics when performing the takeoff of a saut de chat. These larger displacements may be either causative or compensatory factors in the development of AT.

  2. Kinematic variables of table vault on artistic gymnastics

    OpenAIRE

    FERNANDES,Sarah Maria Boldrini; CARRARA,Paulo; SERRÃO,Júlio Cerca; AMADIO,Alberto Carlos; MOCHIZUKI,Luis

    2016-01-01

    Abstract The table vault is an event of male and female Artistics Gymnastics. Although it can be performed in a variety of rotations and body positions in different phases, it can be separated in three groups: handspring, Yurchenko and Tsukahara. It is believed that kinematic variables of vault may vary according to group of vault or gymnast body position, but few studies compares the real differences among the three groups of vaults, comparing and describing the variables in different phases...

  3. Altered Perceptual Sensitivity to Kinematic Invariants in Parkinson's Disease

    OpenAIRE

    Dayan, Eran; Inzelberg, Rivka; Flash, Tamar

    2012-01-01

    Ample evidence exists for coupling between action and perception in neurologically healthy individuals, yet the precise nature of the internal representations shared between these domains remains unclear. One experimentally derived view is that the invariant properties and constraints characterizing movement generation are also manifested during motion perception. One prominent motor invariant is the "two-third power law," describing the strong relation between the kinematics of motion and th...

  4. Detailed solution to a complex kinematics chain manipulator

    International Nuclear Information System (INIS)

    March-Leuba, S.; Jansen, J.F.; Kress, R.L.; Babcock, S.M.

    1992-01-01

    This paper presents a relatively simple method based on planar geometry to analyze the inverse kinematics for closed kinematics chain (CKC) mechanisms. Although the general problem and method of approach are well defined, the study of the inverse kinematics of a closed-chain mechanism is a very complicated one. The current methodology allows closed-form solutions to be found, if a solution exists, for the displacements and velocities of all manipulator joints. Critical design parameters can be identified and optimized by using symbolic models. This paper will focus on planar closed-chain structures extended with a rotational base. However, with open and CKC mechanisms combined in different planes, the extension to the case is straightforward. Further, real-time algorithms are developed that can be handled by existing microprocessor technology. To clarify the methodology, the Soldier Robot Interface Project (SRIP) manipulator is analyzed, and a graphic simulation is presented as a verification of the results. This manipulator has 17 links, 24 one-degree-of-freedom (DOF) joints, and 7 CKC loops working in a plane and a rotational base, which determine its 3 DOFs. The SRIP manipulator allows a decoupled linear motion along the vertical or horizontal directions using only one of its linear actuators. The symbolic solution for the inverse kinematics allows optimization to be performed to further decouple the Cartesian motions by changing link lengths of the manipulator. The conclusion achieved by the optimization is that only two link lengths need to be changed to tune the manipulator for a perfect decoupling at each area of the workspace

  5. The Emotional Modulation of Facial Mimicry: A Kinematic Study

    Directory of Open Access Journals (Sweden)

    Antonella Tramacere

    2018-01-01

    Full Text Available It is well-established that the observation of emotional facial expression induces facial mimicry responses in the observers. However, how the interaction between emotional and motor components of facial expressions can modulate the motor behavior of the perceiver is still unknown. We have developed a kinematic experiment to evaluate the effect of different oro-facial expressions on perceiver's face movements. Participants were asked to perform two movements, i.e., lip stretching and lip protrusion, in response to the observation of four meaningful (i.e., smile, angry-mouth, kiss, and spit and two meaningless mouth gestures. All the stimuli were characterized by different motor patterns (mouth aperture or mouth closure. Response Times and kinematics parameters of the movements (amplitude, duration, and mean velocity were recorded and analyzed. Results evidenced a dissociated effect on reaction times and movement kinematics. We found shorter reaction time when a mouth movement was preceded by the observation of a meaningful and motorically congruent oro-facial gesture, in line with facial mimicry effect. On the contrary, during execution, the perception of smile was associated with the facilitation, in terms of shorter duration and higher velocity of the incongruent movement, i.e., lip protrusion. The same effect resulted in response to kiss and spit that significantly facilitated the execution of lip stretching. We called this phenomenon facial mimicry reversal effect, intended as the overturning of the effect normally observed during facial mimicry. In general, the findings show that both motor features and types of emotional oro-facial gestures (conveying positive or negative valence affect the kinematics of subsequent mouth movements at different levels: while congruent motor features facilitate a general motor response, motor execution could be speeded by gestures that are motorically incongruent with the observed one. Moreover, valence

  6. The Emotional Modulation of Facial Mimicry: A Kinematic Study.

    Science.gov (United States)

    Tramacere, Antonella; Ferrari, Pier F; Gentilucci, Maurizio; Giuffrida, Valeria; De Marco, Doriana

    2017-01-01

    It is well-established that the observation of emotional facial expression induces facial mimicry responses in the observers. However, how the interaction between emotional and motor components of facial expressions can modulate the motor behavior of the perceiver is still unknown. We have developed a kinematic experiment to evaluate the effect of different oro-facial expressions on perceiver's face movements. Participants were asked to perform two movements, i.e., lip stretching and lip protrusion, in response to the observation of four meaningful (i.e., smile, angry-mouth, kiss, and spit) and two meaningless mouth gestures. All the stimuli were characterized by different motor patterns (mouth aperture or mouth closure). Response Times and kinematics parameters of the movements (amplitude, duration, and mean velocity) were recorded and analyzed. Results evidenced a dissociated effect on reaction times and movement kinematics. We found shorter reaction time when a mouth movement was preceded by the observation of a meaningful and motorically congruent oro-facial gesture, in line with facial mimicry effect. On the contrary, during execution, the perception of smile was associated with the facilitation, in terms of shorter duration and higher velocity of the incongruent movement, i.e., lip protrusion. The same effect resulted in response to kiss and spit that significantly facilitated the execution of lip stretching. We called this phenomenon facial mimicry reversal effect , intended as the overturning of the effect normally observed during facial mimicry. In general, the findings show that both motor features and types of emotional oro-facial gestures (conveying positive or negative valence) affect the kinematics of subsequent mouth movements at different levels: while congruent motor features facilitate a general motor response, motor execution could be speeded by gestures that are motorically incongruent with the observed one. Moreover, valence effect depends on

  7. Target Lagrangian kinematic simulation for particle-laden flows.

    Science.gov (United States)

    Murray, S; Lightstone, M F; Tullis, S

    2016-09-01

    The target Lagrangian kinematic simulation method was motivated as a stochastic Lagrangian particle model that better synthesizes turbulence structure, relative to stochastic separated flow models. By this method, the trajectories of particles are constructed according to synthetic turbulent-like fields, which conform to a target Lagrangian integral timescale. In addition to recovering the expected Lagrangian properties of fluid tracers, this method is shown to reproduce the crossing trajectories and continuity effects, in agreement with an experimental benchmark.

  8. Evidence for halo kinematics among cool carbon-rich dwarfs

    Science.gov (United States)

    Farihi, J.; Arendt, A. R.; Machado, H. S.; Whitehouse, L. J.

    2018-04-01

    This paper reports preliminary yet compelling kinematical inferences for N ≳ 600 carbon-rich dwarf stars that demonstrate around 30% to 60% are members of the Galactic halo. The study uses a spectroscopically and non-kinematically selected sample of stars from the SDSS, and cross-correlates these data with three proper motion catalogs based on Gaia DR1 astrometry to generate estimates of their 3-D space velocities. The fraction of stars with halo-like kinematics is roughly 30% for distances based on a limited number of parallax measurements, with the remainder dominated by the thick disk, but close to 60% of the sample lie below an old, metal-poor disk isochrone in reduced proper motion. An ancient population is consistent with an extrinsic origin for C/O >1 in cool dwarfs, where a fixed mass of carbon pollution more readily surmounts lower oxygen abundances, and with a lack of detectable ultraviolet-blue flux from younger white dwarf companions. For an initial stellar mass function that favors low-mass stars as in the Galactic disk, the dC stars are likely to be the dominant source of carbon-enhanced, metal-poor stars in the Galaxy.

  9. Inverse Kinematics for Industrial Robots using Conformal Geometric Algebra

    Directory of Open Access Journals (Sweden)

    Adam L. Kleppe

    2016-01-01

    Full Text Available This paper shows how the recently developed formulation of conformal geometric algebra can be used for analytic inverse kinematics of two six-link industrial manipulators with revolute joints. The paper demonstrates that the solution of the inverse kinematics in this framework relies on the intersection of geometric objects like lines, circles, planes and spheres, which provides the developer with valuable geometric intuition about the problem. It is believed that this will be very useful for new robot geometries and other mechanisms like cranes and topside drilling equipment. The paper extends previous results on inverse kinematics using conformal geometric algebra by providing consistent solutions for the joint angles for the different configurations depending on shoulder left or right, elbow up or down, and wrist flipped or not. Moreover, it is shown how to relate the solution to the Denavit-Hartenberg parameters of the robot. The solutions have been successfully implemented and tested extensively over the whole workspace of the manipulators.

  10. Analysis of a closed-kinematic chain robot manipulator

    Science.gov (United States)

    Nguyen, Charles C.; Pooran, Farhad J.

    1988-01-01

    Presented are the research results from the research grant entitled: Active Control of Robot Manipulators, sponsored by the Goddard Space Flight Center (NASA) under grant number NAG-780. This report considers a class of robot manipulators based on the closed-kinematic chain mechanism (CKCM). This type of robot manipulators mainly consists of two platforms, one is stationary and the other moving, and they are coupled together through a number of in-parallel actuators. Using spatial geometry and homogeneous transformation, a closed-form solution is derived for the inverse kinematic problem of the six-degree-of-freedom manipulator, built to study robotic assembly in space. Iterative Newton Raphson method is employed to solve the forward kinematic problem. Finally, the equations of motion of the above manipulators are obtained by employing the Lagrangian method. Study of the manipulator dynamics is performed using computer simulation whose results show that the robot actuating forces are strongly dependent on the mass and centroid locations of the robot links.

  11. Nozzle Mounting Method Optimization Based on Robot Kinematic Analysis

    Science.gov (United States)

    Chen, Chaoyue; Liao, Hanlin; Montavon, Ghislain; Deng, Sihao

    2016-08-01

    Nowadays, the application of industrial robots in thermal spray is gaining more and more importance. A desired coating quality depends on factors such as a balanced robot performance, a uniform scanning trajectory and stable parameters (e.g. nozzle speed, scanning step, spray angle, standoff distance). These factors also affect the mass and heat transfer as well as the coating formation. Thus, the kinematic optimization of all these aspects plays a key role in order to obtain an optimal coating quality. In this study, the robot performance was optimized from the aspect of nozzle mounting on the robot. An optimized nozzle mounting for a type F4 nozzle was designed, based on the conventional mounting method from the point of view of robot kinematics validated on a virtual robot. Robot kinematic parameters were obtained from the simulation by offline programming software and analyzed by statistical methods. The energy consumptions of different nozzle mounting methods were also compared. The results showed that it was possible to reasonably assign the amount of robot motion to each axis during the process, so achieving a constant nozzle speed. Thus, it is possible optimize robot performance and to economize robot energy.

  12. Foot and Ankle Kinematics During Descent From Varying Step Heights.

    Science.gov (United States)

    Gerstle, Emily E; O'Connor, Kristian; Keenan, Kevin G; Cobb, Stephen C

    2017-12-01

    In the general population, one-third of incidences during step negotiation occur during the transition to level walking. Furthermore, falls during curb negotiation are a common cause of injury in older adults. Distal foot kinematics may be an important factor in determining injury risk associated with transition step negotiation. The purpose of this study was to identify foot and ankle kinematics of uninjured individuals during descent from varying step heights. A 7-segment foot model was used to quantify kinematics as participants walked on a level walkway, stepped down a single step (heights: 5 cm, 15 cm, 25 cm), and continued walking. As step height increased, landing strategy transitioned from the rearfoot to the forefoot, and the rearfoot, lateral and medial midfoot, and medial forefoot became more plantar flexed. During weight acceptance, sagittal plane range of motion of the rearfoot, lateral midfoot, and medial and lateral forefoot increased as step height increased. The changes in landing strategy and distal foot function suggest a less stable ankle position at initial contact and increased demand on the distal foot at initial contact and through the weight acceptance phase of transition step negotiation as step height increases.

  13. Kinematics of Mass Transport Deposits revealed by magnetic fabrics

    Science.gov (United States)

    Weinberger, R.; Levi, T.; Alsop, G. I.; Marco, S.

    2017-08-01

    The internal deformation and movement directions of Mass Transport Deposits (MTDs) are key factors in understanding the kinematics and dynamics of their emplacement. Although these are relatively easy to recover from well-bedded sediments, they are more difficult to deduce from massive beds without visible strain markers. In order to test the applicability of using anisotropy of magnetic susceptibility (AMS) to determine MTD movement, we compare AMS fabrics, with structural measurements of visible kinematic indicators. Our case study involves the structural analysis of slumped lake sediments extensively exposed in MTDs within the Dead Sea Basin. Structural analyses of MTDs outcropping for >100 km reveal radial transport directions toward the basin depocenter. We show that the AMS fabrics display the same transport directions as inferred from structural analyses. Based on this similarity, we outline a robust procedure to obtain the transport direction of slumped MTDs from AMS fabrics. Variations in the magnetic fabrics and anisotropies in fold-thrust systems within the slumps match the various structural domains. We therefore suggest that magnetic fabrics and anisotropy variations in drill cores may reflect internal deformation within the slumps rather than different slumps. Obtaining magnetic fabrics from MTDs provides a viable way to infer the transport directions and internal deformation of MTDs and reconstruct the basin depocenter in ancient settings. The present results also have implications beyond the kinematics of MTDs, as their geometry resembles fold-thrust systems in other geological settings, scales, and tectonic environments.

  14. Integrating concepts and skills: Slope and kinematics graphs

    Science.gov (United States)

    Tonelli, Edward P., Jr.

    The concept of force is a foundational idea in physics. To predict the results of applying forces to objects, a student must be able to interpret data representing changes in distance, time, speed, and acceleration. Comprehension of kinematics concepts requires students to interpret motion graphs, where rates of change are represented as slopes of line segments. Studies have shown that majorities of students who show proficiency with mathematical concepts fail accurately to interpret motion graphs. The primary aim of this study was to examine how students apply their knowledge of slope when interpreting kinematics graphs. To answer the research questions a mixed methods research design, which included a survey and interviews, was adopted. Ninety eight (N=98) high school students completed surveys which were quantitatively analyzed along with qualitative information collected from interviews of students (N=15) and teachers ( N=2). The study showed that students who recalled methods for calculating slopes and speeds calculated slopes accurately, but calculated speeds inaccurately. When comparing the slopes and speeds, most students resorted to calculating instead of visual inspection. Most students recalled and applied memorized rules. Students who calculated slopes and speeds inaccurately failed to recall methods of calculating slopes and speeds, but when comparing speeds, these students connected the concepts of distance and time to the line segments and the rates of change they represented. This study's findings will likely help mathematics and science educators to better assist their students to apply their knowledge of the definition of slope and skills in kinematics concepts.

  15. MALT90 Kinematic Distances to Dense Molecular Clumps

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, J. Scott [Physics Department, Boston University, 590 Commonwealth Avenue, Boston, MA 02215 (United States); Jackson, James M.; Sanhueza, Patricio; Stephens, Ian W. [Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States); Rathborne, J. M. [CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW 1710 (Australia); Foster, J. B. [Department of Astronomy, Yale University, P.O. Box 28101, New Haven, CT 06520-8101 (United States); Contreras, Y. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Longmore, S. N., E-mail: scott@bu.edu [Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom)

    2017-10-01

    Using molecular-line data from the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90), we have estimated kinematic distances to 1905 molecular clumps identified in the ATLASGAL 870 μ m continuum survey over the longitude range 295° <  l  < 350°. The clump velocities were determined using a flux-weighted average of the velocities obtained from Gaussian fits to the HCO{sup +}, HNC, and N{sub 2}H{sup +} (1–0) transitions. The near/far kinematic distance ambiguity was addressed by searching for the presence or absence of absorption or self-absorption features in 21 cm atomic hydrogen spectra from the Southern Galactic Plane Survey. Our algorithm provides an estimation of the reliability of the ambiguity resolution. The Galactic distribution of the clumps indicates positions where the clumps are bunched together, and these locations probably trace the locations of spiral arms. Several clumps fall at the predicted location of the far side of the Scutum–Centaurus arm. Moreover, a number of clumps with positive radial velocities are unambiguously located on the far side of the Milky Way at galactocentric radii beyond the solar circle. The measurement of these kinematic distances, in combination with continuum or molecular-line data, now enables the determination of fundamental parameters such as mass, size, and luminosity for each clump.

  16. KINEMATIC AND KINETIC VARIABLES DIFFER BETWEEN KETTLEBELL SWING STYLES.

    Science.gov (United States)

    Bullock, Garrett S; Schmitt, Abigail C; Shutt, Jason M; Cook, Gray; Butler, Robert J

    2017-06-01

    Kettlebell (KB) and indian club swings (ICS) are used diversely for developing strength and power. It has been proposed that multiple swing techniques can be used interchangeably to elicit similar adaptations within performance training. Hypothesis/Purpose: It was hypothesized that there will be not be a difference in peak joint angles between types of swings. Furthermore, given the nature of the overhead kettlebell swing (OKS), it was hypothesized that the OKS will be associated with a greater cycle time and a greater vertical impulse compared to shoulder height swing (SKS) and ICS. The purpose of this study was to analyze the kinematics and kinetics of the SKS, OKS, and ICS. Cross-sectional cohort. Fifteen healthy subjects underwent 3D biomechanical analysis for assessment of kinematic and kinetic data. Subjects performed two trials of ten repetitions at full effort for each swing in a randomized order using either a standard set of 0.45 kg indian clubs or sex specific KB loads (Female = 12kg, Male = 20kg). Lower extremity sagittal plane kinematics and kinetics were analyzed for peak values during the down and up portions of the swing patterns. Statistical analyses were carried out utilizing one-way ANOVAs ( p power training. 2.

  17. Comparison of trunk kinematics in trunk training exercises and throwing.

    Science.gov (United States)

    Stodden, David F; Campbell, Brian M; Moyer, Todd M

    2008-01-01

    Strength and conditioning professionals, as well as coaches, have emphasized the importance of training the trunk and the benefits it may have on sport performance and reducing the potential for injury. However, no data on the efficacy of trunk training support such claims. The purpose of this study was to examine the maximum differential trunk rotation and maximum angular velocities of the pelvis and upper torso of participants while they performed 4 trunk exercises (seated band rotations, cross-overs, medicine ball throws, and twisters) and compare these trunk exercise kinematics with the trunk kinematics demonstrated in actual throwing performance. Nine NCAA Division I baseball players participated in this study. Each participant's trunk kinematics was analyzed while he performed 5 repetitions of each exercise in both dominant and nondominant rotational directions. Results indicated maximum differentiated rotation in all 4 trunk exercises was similar to maximum differentiated rotation (approximately 50-60 degrees) demonstrated in throwing performance. Maximum angular velocities of the pelvis and upper torso in the trunk exercises were appreciably slower (approximately 50% or less) than the angular velocities demonstrated during throwing performance. Incorporating trunk training exercises that demonstrate sufficient trunk ranges of motion and velocities into a strength and conditioning program may help to increase ball velocity and/or decrease the risk injury.

  18. Kinematic decomposition and classification of octopus arm movements.

    Science.gov (United States)

    Zelman, Ido; Titon, Myriam; Yekutieli, Yoram; Hanassy, Shlomi; Hochner, Binyamin; Flash, Tamar

    2013-01-01

    The octopus arm is a muscular hydrostat and due to its deformable and highly flexible structure it is capable of a rich repertoire of motor behaviors. Its motor control system uses planning principles and control strategies unique to muscular hydrostats. We previously reconstructed a data set of octopus arm movements from records of natural movements using a sequence of 3D curves describing the virtual backbone of arm configurations. Here we describe a novel representation of octopus arm movements in which a movement is characterized by a pair of surfaces that represent the curvature and torsion values of points along the arm as a function of time. This representation allowed us to explore whether the movements are built up of elementary kinematic units by decomposing each surface into a weighted combination of 2D Gaussian functions. The resulting Gaussian functions can be considered as motion primitives at the kinematic level of octopus arm movements. These can be used to examine underlying principles of movement generation. Here we used combination of such kinematic primitives to decompose different octopus arm movements and characterize several movement prototypes according to their composition. The representation and methodology can be applied to the movement of any organ which can be modeled by means of a continuous 3D curve.

  19. Kinematic decomposition and classification of octopus arm movements

    Directory of Open Access Journals (Sweden)

    Ido eZelman

    2013-05-01

    Full Text Available The octopus arm is a muscular hydrostat and due to its deformable and highly flexible structure it is capable of a rich repertoire of motor behaviors. Its motor control system uses planning principles and control strategies unique to muscular hydrostats. We previously reconstructed a data set of octopus arm movements from records of natural movements using a sequence of 3D curves describing the virtual backbone of arm configurations. Here we describe a novel representation of octopus arm movements in which a movement is characterized by a pair of surfaces that represent the curvature and torsion values of points along the arm as a function of time. This representation allowed us to explore whether the movements are built up of elementary kinematic units by decomposing each surface into a weighted combination of 2D Gaussian functions. The resulting Gaussian functions can be considered as motion primitives at the kinematic level of octopus arm movements. These can be used to examine underlying principles of movement generation. Here we used combination of such kinematic primitives to decompose different octopus arm movements and characterize several movement prototypes according to their composition. The representation and methodology can be applied to the movement of any organ which can be modeled by means of a continuous 3D curve.

  20. Kinematic classification of iliotibial band syndrome in runners.

    Science.gov (United States)

    Grau, S; Krauss, I; Maiwald, C; Axmann, D; Horstmann, T; Best, R

    2011-04-01

    Several inconsistent causative biomechanical factors are considered to be crucial in the occurrence of iliotibial band syndrome (ITBS). The focus of this study was on assessing differences in the kinematic characteristics between healthy runners [control group (CO)] and runners with ITBS in order to recommend treatment strategies to deal with this injury. Three-dimensional kinematics of barefoot running was used in the biomechanical setup. Both groups were matched with respect to gender, height and weight. After determining drop outs, the final population comprised 36 subjects (26 male and 10 female): 18 CO and 18 ITBS (13 male and five female, each). Kinematic evaluations indicate less hip adduction and frontal range of motion at the hip joint in runners with ITBS. Furthermore, maximum hip flexion velocity and maximum knee flexion velocity were lower in runners with ITBS. Lack of joint coordination, expressed as earlier hip flexion and a tendency toward earlier knee flexion, was found to be another discriminating variable in subjects with ITBS compared with CO subjects. We assume that an increase in range of motion at the hip joint, stretching of the hip abductors, as well as stretching the hamstrings, calf muscles and hip flexors will help treat ITBS. © 2009 John Wiley & Sons A/S.

  1. Effects of contracture on gait kinematics: A systematic review.

    Science.gov (United States)

    Attias, Michael; Chevalley, Odile; Bonnefoy-Mazure, Alice; De Coulon, Geraldo; Cheze, Laurence; Armand, Stéphane

    2016-03-01

    Contractures of a major joint in the lower limbs may impair human walking in addition to other daily living activities. A contracture is defined as the inability of a joint to perform the full range of motion and excessive resistance during passive mobilization of the joint. Few studies have reported methods describing how to evaluate contractures. Understanding the association among all of these studies seems essential to improve patient management. Therefore, we conducted a systematic review on this topic to elucidate the influence of contractures on gait kinematics. An electronic search in the literature will be conducted. Studies were screened by title and abstract and full texts were evaluated secondarily for definitive inclusion. The quality of the included studies was assessed independently by the two review authors with the Modified Quality Assessment Checklist. The included studies were separated into three categories: pathological contracture versus healthy controls (descriptive), simulated contracture versus healthy controls (experimental), and pre- and post-kinematics after surgical muscle lengthening (surgery). From a total of 4402 references, 112 original articles were selected, and 28 studies were identified in this systematic review. No significant difference between raters was observed on the total score of the Modified Quality Assessment Checklist. Contractures influence walking depending on the location (muscle) and the contracture level (muscle-tendon length). After giving a definition of contracture, this review identified some contracture alterations, such as plantarflexion, knee flexion and hip flexion contractures, with a kinematic description and presented possible different compensations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. The Effect of Direction on Cursor Moving Kinematics

    Directory of Open Access Journals (Sweden)

    Chiu-Ping Lu

    2012-02-01

    Full Text Available There have been only few studies to substantiate the kinematic characteristics of cursor movement. In this study, a quantitative experimental research method was used to explore the effect of moving direction on the kinematics of cursor movement in 24 typical young persons using our previously developed computerized measuring program. The results of multiple one way repeated measures ANOVAs and post hoc LSD tests demonstrated that the moving direction had effects on average velocity, movement time, movement unit and peak velocity. Moving leftward showed better efficiency than moving rightward, upward and downward from the kinematic evidences such as velocity, movement unit and time. Moreover, the unique pattern of the power spectral density (PSD of velocity (strategy for power application explained why the smoothness was still maintained while moving leftward even under an unstable situation with larger momentum. Moreover, the information from this cursor moving study can guide us to relocate the toolbars and icons in the window interface, especially for individuals with physical disabilities whose performances are easily interrupted while controlling the cursor in specific directions.

  3. Kinematic characteristics of tenodesis grasp in C6 quadriplegia.

    Science.gov (United States)

    Mateo, S; Revol, P; Fourtassi, M; Rossetti, Y; Collet, C; Rode, G

    2013-02-01

    Descriptive control case study. To analyze the kinematics of tenodesis grasp in participants with C6 quadriplegia and healthy control participants in a pointing task and two daily life tasks involving a whole hand grip (apple) or a lateral grip (floppy disk). France. Four complete participants with C6 quadriplegia were age matched with four healthy control participants. All participants were right-handed. The measured kinematic parameters were the movement time (MT), the peak velocity (PV), the time of PV (TPV) and the wrist angle in the sagittal plane at movement onset, at the TPV and at the movement end point. The participants with C6 quadriplegia had significantly longer MTs in both prehension tasks. No significant differences in TPV were found between the two groups. Unlike control participants, for both prehension tasks the wrist of participants with C6 quadriplegia was in a neutral position at movement onset, in flexion at the TPV, and in extension at the movement end point. Two main kinematic parameters characterize tenodesis grasp movements in C6 quadriplegics: wrist flexion during reaching and wrist extension during the grasping phase, and increased MT reflecting the time required to adjust the wrist's position to achieve the tenodesis grasp. These characteristics were observed for two different grips (whole hand and lateral grip). These results suggest sequential planning of reaching and tenodesis grasp, and should be taken into account for prehension rehabilitation in patients with quadriplegia.

  4. Pa2 kinematic bond in translational parallel manipulators

    Directory of Open Access Journals (Sweden)

    A. Hernández

    2018-01-01

    Full Text Available The Pa2 pair is composed of two intertwined articulated parallelograms connecting in parallel two links of a kinematic chain. This pair has two translational degrees of freedom leading to a translational plane variable with the position. Currently, the Pa2 pair appears in conceptual designs presented in recent papers. However, its practical application is very limited. One of the reasons for this can be the high number of redundant constraints it has. But, it has to be considered that most of them can be eliminated by replacing wisely the revolute joints by spherical joints. On the other side, the structure of the Pa2 pair contributes to increase the global stiffness of the kinematic chain in which it is mounted. Also, its implementation is a promising alternative to the problematic passive prismatic joints. In this paper, the Pa2 pairs are used in the design of a 3 − P Pa2 parallel manipulator. The potentiality of this design is evaluated and proven after doing the following analyses: direct and inverse kinematics, singularity study, and workspace computation and assessment.

  5. Conceptual design and kinematic analysis of a novel parallel robot for high-speed pick-and-place operations

    Science.gov (United States)

    Meng, Qizhi; Xie, Fugui; Liu, Xin-Jun

    2018-06-01

    This paper deals with the conceptual design, kinematic analysis and workspace identification of a novel four degrees-of-freedom (DOFs) high-speed spatial parallel robot for pick-and-place operations. The proposed spatial parallel robot consists of a base, four arms and a 1½ mobile platform. The mobile platform is a major innovation that avoids output singularity and offers the advantages of both single and double platforms. To investigate the characteristics of the robot's DOFs, a line graph method based on Grassmann line geometry is adopted in mobility analysis. In addition, the inverse kinematics is derived, and the constraint conditions to identify the correct solution are also provided. On the basis of the proposed concept, the workspace of the robot is identified using a set of presupposed parameters by taking input and output transmission index as the performance evaluation criteria.

  6. An engineering geological appraisal of the Chamshir dam foundation using DMR classification and kinematic analysis, southwest of Iran

    Directory of Open Access Journals (Sweden)

    Torabi Kaveh Mehdi

    2011-12-01

    Full Text Available This paper describes the results of engineering geological  investigations and rock mechanics studies carried out at the proposed Chamshir dam site. It is proposed that a 155 m high solid concrete gravity-arc dam be built across the Zuhreh River to the southeast of the city of Gachsaran in south-western Iran. The dam and its associated structures are mainly located on the Mishan formation. Analysis consisted of rock mass classification and a kinematic
    analysis of the dam foundation's rock masses. The studies were carried out in the field and the laboratory. The field studies included geological mapping, intensive discontinuity surveying, core drilling and sampling for laboratory testing. Rock mass classifications were made in line with RMR and DMR classification for the dam foundation. Dam foundation analysis regarding stability using DMR classification and kinematic analysis indicated that the left abutment's rock foundation (area 2 was unstable for planar, wedge and toppling failure modes.

  7. Determining SUSY model parameters and masses at the LHC using cross sections, kinematic edges and other observables

    CERN Document Server

    White, M J; Parker, M A

    2005-01-01

    We address the problem of mass measurements of supersymmetric particles at the Large Hadron Collider, using the ATLAS detector as an example. By using Markov Chain sampling techniques to combine standard measurements of kinematic edges in the invariant mass distributions of decay products with a measurement of a missing $p_T$ cross-section, we show that the precision of mass measurements at the LHC can be dramatically improved, even when we do not assume that we have measured the kinematic endpoints precisely, or that we have identified exactly which particles are involved in the decay chain causing the endpoints. The generality of the technique is demonstrated in a preliminary investigation of a non-universal SUGRA model, in which we relax the requirements of mSUGRA by breaking the degeneracy of the GUT scale gaugino masses. The model studied is compatible with the WMAP limits on dark matter relic density.

  8. Lower-limb kinematics of single-leg squat performance in young adults.

    Science.gov (United States)

    Horan, Sean A; Watson, Steven L; Carty, Christopher P; Sartori, Massimo; Weeks, Benjamin K

    2014-01-01

    To determine the kinematic parameters that characterize good and poor single-leg squat (SLS) performance. A total of 22 healthy young adults free from musculoskeletal impairment were recruited for testing. For each SLS, both two-dimensional video and three-dimensional motion analysis data were collected. Pelvis, hip, and knee angles were calculated using a reliable and validated lower-limb (LL) biomechanical model. Two-dimensional video clips of SLSs were blindly assessed in random order by eight musculoskeletal physiotherapists using a 10-point ordinal scale. To facilitate between-group comparisons, SLS performances were stratified by tertiles corresponding to poor, intermediate, and good SLS performance. Mean ratings of SLS performance assessed by physiotherapists were 8.3 (SD 0.5), 6.8 (SD 0.7), and 4.0 (SD 0.8) for good, intermediate, and poor squats, respectively. Three-dimensional analysis revealed that people whose SLS performance was assessed as poor exhibited increased hip adduction, reduced knee flexion, and increased medio-lateral displacement of the knee joint centre compared to those whose SLS performance was assessed as good (p≤0.05). Overall, poor SLS performance is characterized by inadequate knee flexion and excessive frontal plane motion of the knee and hip. Future investigations of SLS performance should consider standardizing knee flexion angle to illuminate other influential kinematic parameters.

  9. Small-scale kinematic dynamo and non-dynamo in inertial-range turbulence

    International Nuclear Information System (INIS)

    Eyink, Gregory L; Neto, Antonio F

    2010-01-01

    We investigate the Lagrangian mechanism of the kinematic 'fluctuation' magnetic dynamo in a turbulent plasma flow at small magnetic Prandtl numbers. The combined effect of turbulent advection and plasma resistivity is to carry infinitely many field lines to each space point, with the resultant magnetic field at that point given by the average over all the individual line vectors. As a consequence of the roughness of the advecting velocity, this remains true even in the limit of zero resistivity. We show that the presence of the dynamo effect requires sufficient angular correlation of the passive line vectors that arrive simultaneously at the same space point. We illustrate this in detail for the Kazantsev-Kraichnan model of the kinematic dynamo with a Gaussian advecting velocity that is spatially rough and white noise in time. In the regime where dynamo action fails, we also obtain the precise rate of decay of the magnetic energy. These exact results for the model are obtained by a generalization of the 'slow-mode expansion' of Bernard, Gawedzki and Kupiainen to non-Hermitian evolution. Much of our analysis applies also to magnetohydrodynamic turbulence.

  10. Kinematics and M(sub v) calibration of K and M dwarf stars using Hipparcos data

    Science.gov (United States)

    Upgren, A. R.; Ratnatunga, K. U.; Casertano, S.; Weis, E.

    1997-01-01

    The luminosities and kinematics of lower main sequence stars in a spectroscopically selected sample covering spectral types K 3 to M 5 are determined using Hipparcos parallaxes and proper motions. The stars separate into two kinematically distinct components, called young disk and old disk components. The young component has velocity dispersion (30, 17, 12) km/s in the U, V and W directions, respectively, and features an asymmetric drift of 8 km/s, a vertex deviation of 10 +/- 3 deg and an absolute magnitude of 10.48 mag at color (R - I)(sub Kron) = 1.0 mag. The respective features of the old component are: (56, 34, 31) km/s, 28 km/s and 0.6 mag at the same color. The slope and intrinsic width of the magnitude calibration of each component are determined. The analysis is used to investigate the possible presence of residual systematic discrepancies of the model with Hipparcos data. There are indications of a possible underestimation of the parallax errors.

  11. Applicability of Kinematic and Diffusive models for mud-flows: a steady state analysis

    Science.gov (United States)

    Di Cristo, Cristiana; Iervolino, Michele; Vacca, Andrea

    2018-04-01

    The paper investigates the applicability of Kinematic and Diffusive Wave models for mud-flows with a power-law shear-thinning rheology. In analogy with a well-known approach for turbulent clear-water flows, the study compares the steady flow depth profiles predicted by approximated models with those of the Full Dynamic Wave one. For all the models and assuming an infinitely wide channel, the analytical solution of the flow depth profiles, in terms of hypergeometric functions, is derived. The accuracy of the approximated models is assessed by computing the average, along the channel length, of the errors, for several values of the Froude and kinematic wave numbers. Assuming the threshold value of the error equal to 5%, the applicability conditions of the two approximations have been individuated for several values of the power-law exponent, showing a crucial role of the rheology. The comparison with the clear-water results indicates that applicability criteria for clear-water flows do not apply to shear-thinning fluids, potentially leading to an incorrect use of approximated models if the rheology is not properly accounted for.

  12. Technique, muscle activity and kinematic differences in young adults texting on mobile phones.

    Science.gov (United States)

    Gustafsson, Ewa; Johnson, Peter W; Lindegård, Agneta; Hagberg, Mats

    2011-05-01

    The aim of this study was to investigate whether there are differences in technique between young adults with and without musculoskeletal symptoms when using a mobile phone for texting and whether there are differences in muscle activity and kinematics between different texting techniques. A total of 56 young adults performed a standardised texting task on a mobile phone. Their texting techniques were registered using an observation protocol. The muscular activity in six muscles in the right forearm/hand and both shoulders were registered by surface electromyography and the thumb abduction/adduction and flexion/extension were registered using a biaxial electrogoniometer. Differences in texting techniques were found between the symptomatic and the asymptomatic group, with a higher proportion of sitting with back support and forearm support and with a neutral head position in the asymptomatic group. Differences in muscle activity and kinematics were also found between different texting techniques. The differences in texting technique between symptomatic and asymptomatic subjects cannot be explained by them having symptoms but may be a possible contribution to their symptoms. STATEMENT OF RELEVANCE: There has been a dramatically increased use of mobile phones for texting especially among young people during the last years. A better understanding of the physical exposure associated with the intensive use is important in order to prevent the development of musculoskeletal disorders and decreased work ability related to this use.

  13. Treatment of photon radiation in kinematics fits at future e{sup +}e{sup -} colliders

    Energy Technology Data Exchange (ETDEWEB)

    Beckmann, M.; List, J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); List, B. [Hamburg Univ. (Germany). Inst. fuer Experimentalphysik

    2010-05-15

    Kinematic fitting, where constraints such as energy and momentum conservation are imposed on measured four-vectors of jets and leptons, is an important tool to improve the resolution in high-energy physics experiments. At future e{sup +}e{sup -} colliders, photon radiation parallel to the beam carrying away large amounts of energy and momentum will become a challenge for kinematic fitting. A photon with longitudinal momentum p{sub z,{gamma}} ({eta}) is introduced, which is parametrized such that {eta} follows a normal distribution. In the fit, {eta} is treated as having a measured value of zero, which corresponds to p{sub z,{gamma}}, = 0. As a result, fits with constraints on energy and momentum conservation converge well even in the presence of a highly energetic photon, while the resolution of fits without such a photon is retained. A fully simulated and reconstructed e{sup +}e{sup -}{yields}q anti qq anti q event sample at {radical}(s)=500 GeV is used to investigate the performance of this method under realistic conditions, as expected at the International Linear Collider. (orig.)

  14. Nordic hamstring exercise training alters knee joint kinematics and hamstring activation patterns in young men.

    Science.gov (United States)

    Delahunt, Eamonn; McGroarty, Mark; De Vito, Giuseppe; Ditroilo, Massimiliano

    2016-04-01

    To investigate the kinematic and muscle activation adaptations during performance of the Nordic hamstring exercise (NHE) to a 6-week eccentric hamstring training programme using the NHE as the sole mode of exercise. Twenty-nine healthy males were randomly allocated to a control (CG) or intervention (IG) group. The IG participated in a 6-week eccentric hamstring exercise programme using the NHE. The findings of the present study were that a 6-week eccentric hamstring training programme improved eccentric hamstring muscle strength (202.4 vs. 177.4 nm, p = 0.0002, Cohen's d = 0.97) and optimized kinematic (longer control of the forward fall component of the NHE, 68.1° vs. 73.7°, p = 0.022, Cohen's d = 0.90) and neuromuscular parameters (increased electromyographic activity of the hamstrings, 83.2 vs. 56.6 % and 92.0 vs. 54.2 %, p 1.25) associated with NHE performance. This study provides some insight into potential mechanisms by which an eccentric hamstring exercise programme utilizing the NHE as the mode of exercise may result in an improvement in hamstring muscle control during eccentric contractions.

  15. Treatment of photon radiation in kinematics fits at future e+e- colliders

    International Nuclear Information System (INIS)

    Beckmann, M.; List, J.; List, B.

    2010-05-01

    Kinematic fitting, where constraints such as energy and momentum conservation are imposed on measured four-vectors of jets and leptons, is an important tool to improve the resolution in high-energy physics experiments. At future e + e - colliders, photon radiation parallel to the beam carrying away large amounts of energy and momentum will become a challenge for kinematic fitting. A photon with longitudinal momentum p z,γ (η) is introduced, which is parametrized such that η follows a normal distribution. In the fit, η is treated as having a measured value of zero, which corresponds to p z,γ , = 0. As a result, fits with constraints on energy and momentum conservation converge well even in the presence of a highly energetic photon, while the resolution of fits without such a photon is retained. A fully simulated and reconstructed e + e - →q anti qq anti q event sample at √(s)=500 GeV is used to investigate the performance of this method under realistic conditions, as expected at the International Linear Collider. (orig.)

  16. Auditory imagery shapes movement timing and kinematics: evidence from a musical task.

    Science.gov (United States)

    Keller, Peter E; Dalla Bella, Simone; Koch, Iring

    2010-04-01

    The role of anticipatory auditory imagery in music-like sequential action was investigated by examining timing accuracy and kinematics using a motion capture system. Musicians responded to metronomic pacing signals by producing three unpaced taps on three vertically aligned keys at the given tempo. Taps triggered tones in two out of three blocked feedback conditions, where key-to-tone mappings were compatible or incompatible in terms of spatial and pitch height. Results indicate that, while timing was most accurate without tones, movements were smaller in amplitude and less forceful (i.e., acceleration prior to impact was lowest) when tones were present. Moreover, timing was more accurate and movements were less forceful with compatible than with incompatible auditory feedback. Observing these effects at the first tap (before tone onset) suggests that anticipatory auditory imagery modulates the temporal kinematics of regularly timed auditory action sequences, like those found in music. Such cross-modal ideomotor processes may function to facilitate planning efficiency and biomechanical economy in voluntary action. Copyright 2010 APA, all rights reserved.

  17. Swallowing Kinematics and Factors Associated with Laryngeal Penetration and Aspiration in Stroke Survivors with Dysphagia.

    Science.gov (United States)

    Seo, Han Gil; Oh, Byung-Mo; Han, Tai Ryoon

    2016-04-01

    The purpose of this study was to investigate swallowing kinematics and explore kinematic factors related with penetration-aspiration in patients with post-stroke dysphagia. Videofluoroscopic images of 68 patients with post-stroke dysphagia and 34 sex- and age-matched healthy controls swallowing a thin liquid were quantitatively analyzed using two-dimensional motion digitization. The measurements included the movement distances and velocities of the hyoid and larynx, and the maximal tilt angles and angular velocities of the epiglottis. All velocity variables were significantly decreased in the stroke patients compared to the controls. There was a significant difference in the maximal horizontal displacement of the larynx, but there were no significant differences in other displacements of the larynx, the maximal displacements of the hyoid bone, and the maximum tilt angle of the epiglottis between the two groups. The maximal tilt angle of the epiglottis was lower in the aspiration subgroup than in the no penetration/aspiration and penetration subgroups as well as the controls. The maximal tilt angle from the y axis showed a dichotomous pattern at 90° of the angle, and all 11 patients with an angle dysphagia. The association of reduced epiglottic movement with the risk of aspiration in patients with post-stroke dysphagia was supported by the quantitative analysis.

  18. Segmental in vivo vertebral kinematics at the walk, trot and canter: a preliminary study.

    Science.gov (United States)

    Haussler, K K; Bertram, J E; Gellman, K; Hermanson, J W

    2001-04-01

    Understanding the pathophysiology of equine back problems, for clinical evaluation, treatment or injury prevention, requires understanding of the normal 3-dimensional motion characteristics of the vertebral column. Recent studies have investigated regional vertebral kinematics; however, there are no reported measures of direct in vivo segmental vertebral kinematics in exercising horses. Relative movements between 2 adjacent vertebrae were recorded for 3 horses that were clinically sound and did not have a known history of a back problem. A transducer consisting of 2 fixtures and an array of liquid metal strain gauges (LMSGs) was used to measure 3-dimensional segmental vertebral motion. The transducer was attached directly to Steinmann pins implanted in the dorsal spinous processes of adjacent vertebrae in 3 vertebral regions: thoracic (T14 to T16), lumbar (L1 to L3) and lumbosacral (L6 to S2). Rotational displacements between adjacent vertebrae were calculated from the differential outputs of the LMSG array during walk, trot and canter on a treadmill. Peak magnitudes of dorsoventral flexion, lateral bending and axial rotation were recorded continuously for each stride. The largest motion of the 3 instrumented vertebral segments was at the lumbosacral junction. In general, the greatest magnitude of segmental vertebral motion occurred during the canter and the least during the trot. The dynamic and continuous measure of 3-dimensional in vivo segmental vertebral motion provides an important new perspective for evaluating vertebral motion and back problems in horses.

  19. Kinematic analysis of jaw function in children following traumatic brain injury.

    Science.gov (United States)

    Loh, E W L; Goozée, J V; Murdoch, B E

    2005-07-01

    To investigate jaw movements in children following traumatic brain injury (TBI) during speech using electromagnetic articulography (EMA). Jaw movements of two non-dysarthric children (aged 12.75 and 13.08 years) who had sustained a TBI were recorded using the AG-100 EMA system (Carstens Medizineletronik) during word-initial consonant productions. Mean quantitative kinematic parameters and coefficient of variation (variability) values were calculated and individually compared to the mean values obtained by a group of six control children (mean age 12.57 years, SD 1.52). The two children with TBI exhibited word-initial consonant jaw movement durations that were comparable to the control children, with sub-clinical reductions in speed being offset by reduced distances. Differences were observed between the two children in jaw kinematic variability, with one child exhibiting increased variability, while the other child demonstrated reduced or comparable variability compared to the control group. Possible sub-clinical impairments of jaw movement for speech were exhibited by two children who had sustained a TBI, providing insight into the consequences of TBI on speech motor control development.

  20. Analytical Kinematics and Coupled Vibrations Analysis of Mechanical System Operated by Solar Array Drive Assembly

    Science.gov (United States)

    Sattar, M.; Wei, C.; Jalali, A.; Sattar, R.

    2017-07-01

    To address the impact of solar array (SA) anomalies and vibrations on performance of precision space-based operations, it is important to complete its accurate jitter analysis. This work provides mathematical modelling scheme to approximate kinematics and coupled micro disturbance dynamics of rigid load supported and operated by solar array drive assembly (SADA). SADA employed in analysis provides a step wave excitation torque to activate the system. Analytical investigations into kinematics is accomplished by using generalized linear and Euler angle coordinates, applying multi-body dynamics concepts and transformations principles. Theoretical model is extended, to develop equations of motion (EoM), through energy method (Lagrange equation). The main emphasis is to research coupled frequency response by determining energies dissipated and observing dynamic behaviour of internal vibratory systems of SADA. The disturbance model captures discrete active harmonics of SADA, natural modes and vibration amplifications caused by interactions between active harmonics and structural modes of mechanical assembly. The proposed methodology can help to predict true micro disturbance nature of SADA operating rigid load. Moreover, performance outputs may be compared against actual mission requirements to assess precise spacecraft controller design to meet next space generation stringent accuracy goals.

  1. Comparison of skating kinetics and kinematics on ice and on a synthetic surface.

    Science.gov (United States)

    Stidwill, T J; Pearsall, David; Turcotte, Rene

    2010-03-01

    The recent popularization and technological improvements of synthetic or artificial ice surfaces provide an attractive alternative to real ice in venues where the latter is impractical to install. Potentially, synthetic ice (SI) may be installed in controlled laboratory settings to permit detailed biomechanical analysis of skating manoeuvres. Unknown, however, is the extent to which skating on SI replicates skating on traditional ice (ICE). Hence, the purpose of this study was to compare kinetic and kinematic forward skating parameters between SI and ICE surfaces. With 11 male hockey players, a portable strain gauge system adhered to the outside of the skate blade holder was used to measure skate propulsive force synchronized with electrogoniometers for tracking dynamic knee and ankle movements during forward skating acceleration. In general, the kinetic and kinematic variables investigated in this study showed minimal differences between the two surfaces (P > 0.06), and no individual variable differences were identified between the two surfaces (P > or = 0.1) with the exception of greater knee extension on SI than ICE (15.2 degrees to 11.0 degrees; P skating, and thus offer the potential for valid analogous conditions for in-lab testing and training.

  2. VOLUMETRIC ERROR COMPENSATION IN FIVE-AXIS CNC MACHINING CENTER THROUGH KINEMATICS MODELING OF GEOMETRIC ERROR

    Directory of Open Access Journals (Sweden)

    Pooyan Vahidi Pashsaki

    2016-06-01

    Full Text Available Accuracy of a five-axis CNC machine tool is affected by a vast number of error sources. This paper investigates volumetric error modeling and its compensation to the basis for creation of new tool path for improvement of work pieces accuracy. The volumetric error model of a five-axis machine tool with the configuration RTTTR (tilting head B-axis and rotary table in work piece side A΄ was set up taking into consideration rigid body kinematics and homogeneous transformation matrix, in which 43 error components are included. Volumetric error comprises 43 error components that can separately reduce geometrical and dimensional accuracy of work pieces. The machining accuracy of work piece is guaranteed due to the position of the cutting tool center point (TCP relative to the work piece. The cutting tool is deviated from its ideal position relative to the work piece and machining error is experienced. For compensation process detection of the present tool path and analysis of the RTTTR five-axis CNC machine tools geometrical error, translating current position of component to compensated positions using the Kinematics error model, converting newly created component to new tool paths using the compensation algorithms and finally editing old G-codes using G-code generator algorithm have been employed.

  3. Kinematic hand parameters in front crawl at different paces of swimming.

    Science.gov (United States)

    Samson, Mathias; Monnet, Tony; Bernard, Anthony; Lacouture, Patrick; David, Laurent

    2015-11-05

    The aim of this study was to investigate the evolution of kinematic hand parameters (sweepback angle, angle of attack, velocity, acceleration and orientation of the hand relative to the absolute coordinate system) throughout an aquatic stroke and to study the possible modifications caused by a variation of the swimming pace. Seventeen competitive swimmers swam at long distance, middle distance and sprint paces. Parameters were calculated from the trajectory of seven markers on the hand measured with an optoelectronic system. Results showed that kinematic hand parameters evolve differently depending on the pace. Angle of attack, sweepback angle, acceleration and orientation of the hand do not vary significantly. The velocity of the hand increases when the pace increases, but only during the less propulsive phases (entry and stretch and downsweep to catch). The more the pace increases and the more the absolute durations of the entry and stretch and downsweep to catch phases decrease. Absolute durations of the insweep and upsweep phases remain constant. During these phases, the propulsive hand forces calculated do not vary significantly when the pace increases. The increase of swimming pace is then explained by the swimmer's capacity to maintain propulsive phases rather than increasing the force generation within each cycle. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Acute toxicity effects of perfluorooctane sulfonate on sperm vitality, kinematics and fertilization success in zebrafish

    Science.gov (United States)

    Xia, Jigang; Niu, Cuijuan

    2017-07-01

    Perfluorooctane sulfonate (PFOS) has emerged as one of the most concerning contaminants in recent years. This study aimed to investigate the acute toxicity effect of PFOS on sperm viability, kinematics and fertilization success in zebrafish ( Danio rerio). Sperm were activated in aqueous media containing a range of PFOS concentrations (0, 0.09, 0.9 and 9 mg/L). Viabilities and kinematics of the sperm exposed to different PFOS treatments were assessed via computer-assisted sperm analysis (CASA) at 20, 40, 60, and 80 s after activation. PFOS exposure decreased the percentage of motile sperm, the curvilinear velocity (VCL), and the mean angular displacement (MAD) of spermatozoa, but showed no influence on the straight-line velocity (VSL) or the angular path velocity (VAP). Furthermore, a significant decrease in fertilization success was observed in spermatozoa that were exposed to 0.9 mg/L PFOS or more. These findings indicate that PFOS pollution in natural aquatic environment may be a potential threaten to successful reproduction of fish.

  5. Study on individual stochastic model of GNSS observations for precise kinematic applications

    Science.gov (United States)

    Próchniewicz, Dominik; Szpunar, Ryszard

    2015-04-01

    The proper definition of mathematical positioning model, which is defined by functional and stochastic models, is a prerequisite to obtain the optimal estimation of unknown parameters. Especially important in this definition is realistic modelling of stochastic properties of observations, which are more receiver-dependent and time-varying than deterministic relationships. This is particularly true with respect to precise kinematic applications which are characterized by weakening model strength. In this case, incorrect or simplified definition of stochastic model causes that the performance of ambiguity resolution and accuracy of position estimation can be limited. In this study we investigate the methods of describing the measurement noise of GNSS observations and its impact to derive precise kinematic positioning model. In particular stochastic modelling of individual components of the variance-covariance matrix of observation noise performed using observations from a very short baseline and laboratory GNSS signal generator, is analyzed. Experimental test results indicate that the utilizing the individual stochastic model of observations including elevation dependency and cross-correlation instead of assumption that raw measurements are independent with the same variance improves the performance of ambiguity resolution as well as rover positioning accuracy. This shows that the proposed stochastic assessment method could be a important part in complex calibration procedure of GNSS equipment.

  6. Unveiling the inner morphology and gas kinematics of NGC 5135 with ALMA

    Science.gov (United States)

    Sabatini, G.; Gruppioni, C.; Massardi, M.; Giannetti, A.; Burkutean, S.; Cimatti, A.; Pozzi, F.; Talia, M.

    2018-06-01

    The local Seyfert 2 galaxy NGC 5135, thanks to its almost face-on appearance, a bulge overdensity of stars, the presence of a large-scale bar, an active galactic nucleus (AGN) and a supernova remnant, is an excellent target to investigate the dynamics of inflows, outflows, star formation, and AGN feedback. Here, we present a reconstruction of the gas morphology and kinematics in the inner regions of this galaxy, based on the analysis of Atacama Large Millimeter Array (ALMA) archival data. For this purpose, we combine the available ˜100 pc resolution ALMA 1.3 and 0.45 mm observations of dust continuum emission, the spectroscopic maps of two transitions of the CO molecule (tracer of molecular gas mass in star-forming and nuclear regions), and of the CS molecule (tracer of the dense star-forming regions) with the outcome of the spectral energy distribution decomposition. By applying the 3DBAROLO software (3D-Based Analysis of Rotating Objects from Line Observations), we have been able to fit the galaxy rotation curve using a 3D tilted-ring model of the disc. Most of the observed emitting features are described by our kinematic model. We also attempt an interpretation for the emission in a few regions that the axisymmetric model fails to reproduce. The most relevant of these is a region at the northern edge of the inner bar, where multiple velocity components overlap, as a possible consequence of the expansion of a superbubble.

  7. Validation of a protocol for the estimation of three-dimensional body center of mass kinematics in sport.

    Science.gov (United States)

    Mapelli, Andrea; Zago, Matteo; Fusini, Laura; Galante, Domenico; Colombo, Andrea; Sforza, Chiarella

    2014-01-01

    Since strictly related to balance and stability control, body center of mass (CoM) kinematics is a relevant quantity in sport surveys. Many methods have been proposed to estimate CoM displacement. Among them, segmental method appears to be suitable to investigate CoM kinematics in sport: human body is assumed as a system of rigid bodies, hence the whole-body CoM is calculated as the weighted average of the CoM of each segment. The number of landmarks represents a crucial choice in the protocol design process: one have to find the proper compromise between accuracy and invasivity. In this study, using a motion analysis system, a protocol based upon the segmental method is validated, adopting an anatomical model comprising 14 landmarks. Two sets of experiments were conducted. Firstly, our protocol was compared to the ground reaction force method (GRF), accounted as a standard in CoM estimation. In the second experiment, we investigated the aerial phase typical of many disciplines, comparing our protocol with: (1) an absolute reference, the parabolic regression of the vertical CoM trajectory during the time of flight; (2) two common approaches to estimate CoM kinematics in gait, known as sacrum and reconstructed pelvis methods. Recognized accuracy indexes proved that the results obtained were comparable to the GRF; what is more, during the aerial phases our protocol showed to be significantly more accurate than the two other methods. The protocol assessed can therefore be adopted as a reliable tool for CoM kinematics estimation in further sport researches. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Kinematics of fast cervical rotations in persons with chronic neck pain: a cross-sectional and reliability study.

    Science.gov (United States)

    Röijezon, Ulrik; Djupsjöbacka, Mats; Björklund, Martin; Häger-Ross, Charlotte; Grip, Helena; Liebermann, Dario G

    2010-09-27

    Assessment of sensorimotor function is useful for classification and treatment evaluation of neck pain disorders. Several studies have investigated various aspects of cervical motor functions. Most of these have involved slow or self-paced movements, while few have investigated fast cervical movements. Moreover, the reliability of assessment of fast cervical axial rotation has, to our knowledge, not been evaluated before. Cervical kinematics was assessed during fast axial head rotations in 118 women with chronic nonspecific neck pain (NS) and compared to 49 healthy controls (CON). The relationship between cervical kinematics and symptoms, self-rated functioning and fear of movement was evaluated in the NS group. A sub-sample of 16 NS and 16 CON was re-tested after one week to assess the reliability of kinematic variables. Six cervical kinematic variables were calculated: peak speed, range of movement, conjunct movements and three variables related to the shape of the speed profile. Together, peak speed and conjunct movements had a sensitivity of 76% and a specificity of 78% in discriminating between NS and CON, of which the major part could be attributed to peak speed (NS: 226 ± 88°/s and CON: 348 ± 92°/s, p conjunct movements was poor. Peak speed of fast cervical axial rotations is reduced in people with chronic neck pain, and even further reduced in subjects with concomitant low back pain. Fast cervical rotation test seems to be a reliable and valid tool for assessment of neck pain disorders on group level, while a rather large between subject variation and overlap between groups calls for caution in the interpretation of individual assessments.

  9. Climbing fibers predict movement kinematics and performance errors.

    Science.gov (United States)

    Streng, Martha L; Popa, Laurentiu S; Ebner, Timothy J

    2017-09-01

    Requisite for understanding cerebellar function is a complete characterization of the signals provided by complex spike (CS) discharge of Purkinje cells, the output neurons of the cerebellar cortex. Numerous studies have provided insights into CS function, with the most predominant view being that they are evoked by error events. However, several reports suggest that CSs encode other aspects of movements and do not always respond to errors or unexpected perturbations. Here, we evaluated CS firing during a pseudo-random manual tracking task in the monkey ( Macaca mulatta ). This task provides extensive coverage of the work space and relative independence of movement parameters, delivering a robust data set to assess the signals that activate climbing fibers. Using reverse correlation, we determined feedforward and feedback CSs firing probability maps with position, velocity, and acceleration, as well as position error, a measure of tracking performance. The direction and magnitude of the CS modulation were quantified using linear regression analysis. The major findings are that CSs significantly encode all three kinematic parameters and position error, with acceleration modulation particularly common. The modulation is not related to "events," either for position error or kinematics. Instead, CSs are spatially tuned and provide a linear representation of each parameter evaluated. The CS modulation is largely predictive. Similar analyses show that the simple spike firing is modulated by the same parameters as the CSs. Therefore, CSs carry a broader array of signals than previously described and argue for climbing fiber input having a prominent role in online motor control. NEW & NOTEWORTHY This article demonstrates that complex spike (CS) discharge of cerebellar Purkinje cells encodes multiple parameters of movement, including motor errors and kinematics. The CS firing is not driven by error or kinematic events; instead it provides a linear representation of each

  10. On use of radial evanescence remain term in kinematic hardening

    International Nuclear Information System (INIS)

    Geyer, P.

    1995-10-01

    A fine modelling of the material' behaviour can be necessary to study the mechanical strength of nuclear power plant' components under cyclic loads. Ratchetting is one of the last phenomena for which numerical models have to be improved. We discuss in this paper on use of radial evanescence remain term in kinematic hardening to improve the description of ratchetting in biaxial loading tests. It's well known that Chaboche elastoplastic model with two non linear kinematic hardening variables initially proposed by Armstrong and Frederick, usually over-predicts accumulation of ratchetting strain. Burlet and Cailletaud proposed in 1987 a non linear kinematic rule with a radial evanescence remain term. The two models lead to identical formulation for proportional loadings. In the case of a biaxial loading test (primary+secondary loading), Burlet and Cailletaud model leads to accommodation, when Chaboche one's leads to ratchetting with a constant increment of strain. So we can have an under-estimate with the first model and an over-estimate with the second. An easy method to improve the description of ratchetting is to combine the two kinematic rules. Such an idea is already used by Delobelle in his model. With analytical results in the case of tension-torsion tests, we show in a first part of the paper, the interest of radial evanescence remain term in the non linear kinematic rule to describe ratchetting: we give the conditions to get adaptation, accommodation or ratchetting and the value of the strain increment in the last case. In the second part of the paper, we propose to modify the elastoplastic Chaboche model by coupling the two types of hardening by means of two scalar parameters which can be identified independently on biaxial loading tests. Identification of these two parameters returns to speculate on the directions of strain in order to adjust the ratchetting to experimental observations. We use the experimental results on the austenitic steel 316L at room

  11. Bio-Inspired Design and Kinematic Analysis of Dung Beetle-Like Legs

    DEFF Research Database (Denmark)

    Aditya, Sai Krishna Venkata; Ignasov, Jevgeni; Filonenko, Konstantin

    2017-01-01

    The African dung beetle Scarabaeus galenus can use its front legs to walk and manipulate or form a dung ball. The interesting multifunctional legs have not been fully investigated or even used as inspiration for robot leg design. Thus, in this paper, we present the development of real dung beetle......-like front legs based on biological investigation. As a result, each leg consists of three main segments which were built using 3D printing. The segments were combined with in total four active DOFs in order to mimic locomotion and object manipulation of the beetle. Kinematics analysis of the leg was also...... performed to identify its workspace as well as to design its trajectory. To this end, the study contributes not only novel multifunctional robotic legs but also the methodology of the bio-inspired leg design....

  12. Analog modeling and kinematic restoration of inverted hangingwall synclinal basins developed above syn-kinematic salt: Application to the Lusitanian and Parentis basins

    Science.gov (United States)

    Roma, Maria; Vidal-Royo, Oskar; McClay, Ken; Ferrer, Oriol; Muñoz, Josep Anton

    2017-04-01

    The formation of hagingwall syncline basins is basically constrained by the geometry of the basement-involved fault, but also by salt distribution . The formation of such basins is common around the Iberian Peninsula (e.g. Lusitanian, Parentis, Basque-Cantabian, Cameros and Organyà basins) where Upper Triassic (Keuper) salt governed their polyphasic Mesozoic extension and their subsequent Alpine inversion. In this scenario, a precise interpretation of the sub-salt faults geometry and a reconstruction of the initial salt thickness are key to understand the kinematic evolution of such basins. Using an experimental approach (sandbox models) and these Mesozoic basins as natural analogues, the aim of this work is to: 1) investigate the main parameters that controlled the formation and evolution of hagingwall syncline basins analyzing the role of syn-kinematic salt during extension and subsequent inversion; and 2) quantify the deformation and salt mobilization based on restoration of analog model cross sections. The experimental results demonstrate that premature welds are developed by salt deflation with consequent upward propagation of the basal fault in salt-bearing rift systems with a large amount of extension,. In contrast, thicker salt inhibits the upward fault propagation, which results into a further salt migration and development of a hagingwall syncline basins flanked by salt walls. The inherited extensional architecture as well as salt continuity dramatically controlled subsequent inversion. Shortening initially produced the folding and the uplift of the synclinal basins. Minor reverse faults form as a consequence of overtightening of welded diapir stems. However, no trace of reverse faulting is found around diapirs stems, as ductile unit is still available for extrusion, squeezing and accommodation of shortening. Restoration of the sandbox models has demonstrated that this is a powerful tool to unravel the complex structures in the models and this may

  13. Differences between kinematic synergies and muscle synergies during two-digit grasping

    Directory of Open Access Journals (Sweden)

    Michele eTagliabue

    2015-03-01

    Full Text Available The large number of mechanical degrees of freedom of the hand is not fully exploited during actual movements such as grasping. Usually, angular movements in various joints tend to be coupled, and EMG activities in different hand muscles tend to be correlated. The occurrence of covariation in the former was termed kinematic synergies, in the latter muscle synergies. This study addresses two questions: (i Whether kinematic and muscle synergies can simultaneously accommodate for kinematic and kinetic constraints. (ii If so, whether there is an interrelation between kinematic and muscle synergies. We used a reach-grasp-and-pull paradigm and recorded the hand kinematics as well as 8 surface EMGs. Subjects had to either perform a precision grip or side grip and had to modify their grip force in order to displace an object against a low or high load. The analysis was subdivided into three epochs: reach, grasp-and-pull, and static hold. Principal component analysis (PCA, temporal or static was performed separately for all three epochs, in the kinematic and in the EMG domain. PCA revealed that (i Kinematic- and muscle-synergies can simultaneously accommodate kinematic (grip type and kinetic task constraints (load condition. (ii Upcoming grip and load conditions of the grasp are represented in kinematic- and muscle-synergies already during reach. Phase plane plots of the principal muscle-synergy against the principal kinematic synergy revealed (iii that the muscle-synergy is linked (correlated, and in phase advance to the kinematic synergy during reach and during grasp-and-pull. Furthermore (iv, pair-wise correlations of EMGs during hold suggest that muscle-synergies are (in part implemented by coactivation of muscles through common input. Together, these results suggest that kinematic synergies have (at least in part their origin not just in muscular activation, but in synergiestic muscle activation. In short: kinematic synergies may result from muscle

  14. Determination of patellofemoral pain sub-groups and development of a method for predicting treatment outcome using running gait kinematics.

    Science.gov (United States)

    Watari, Ricky; Kobsar, Dylan; Phinyomark, Angkoon; Osis, Sean; Ferber, Reed

    2016-10-01

    Not all patients with patellofemoral pain exhibit successful outcomes following exercise therapy. Thus, the ability to identify patellofemoral pain subgroups related to treatment response is important for the development of optimal therapeutic strategies to improve rehabilitation outcomes. The purpose of this study was to use baseline running gait kinematic and clinical outcome variables to classify patellofemoral pain patients on treatment response retrospectively. Forty-one individuals with patellofemoral pain that underwent a 6-week exercise intervention program were sub-grouped as treatment Responders (n=28) and Non-responders (n=13) based on self-reported measures of pain and function. Baseline three-dimensional running kinematics, and self-reported measures underwent a linear discriminant analysis of the principal components of the variables to retrospectively classify participants based on treatment response. The significance of the discriminant function was verified with a Wilk's lambda test (α=0.05). The model selected 2 gait principal components and had a 78.1% classification accuracy. Overall, Non-responders exhibited greater ankle dorsiflexion, knee abduction and hip flexion during the swing phase and greater ankle inversion during the stance phase, compared to Responders. This is the first study to investigate an objective method to use baseline kinematic and self-report outcome variables to classify on patellofemoral pain treatment outcome. This study represents a significant first step towards a method to help clinicians make evidence-informed decisions regarding optimal treatment strategies for patients with patellofemoral pain. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. The effects of military body armour on trunk and hip kinematics during performance of manual handling tasks (.).

    Science.gov (United States)

    Lenton, Gavin; Aisbett, Brad; Neesham-Smith, Daniel; Carvajal, Alvaro; Netto, Kevin

    2016-06-01

    Musculoskeletal injuries are reported as burdening the military. An identified risk factor for injury is carrying heavy loads; however, soldiers are also required to wear their load as body armour. To investigate the effects of body armour on trunk and hip kinematics during military-specific manual handling tasks, 16 males completed 3 tasks while wearing each of 4 body armour conditions plus a control. Three-dimensional motion analysis captured and quantified all kinematic data. Average trunk flexion for the weightiest armour type was higher compared with control during the carry component of the ammunition box lift (p armour types compared with control during the ammunition box place component (p armour occurred independent of armour design. In order to optimise armour design, manufacturers need to work with end-users to explore how armour configurations interact with range of personal and situational factors in operationally relevant environments. Practitioner Summary: Musculoskeletal injuries are reported as burdening the military and may relate to body armour wear. Body armour increased trunk flexion and reduced trunk rotation during military-specific lifting and carrying tasks. The altered kinematics may contribute to injury risk, but more research is required.

  16. Shoulder kinematics and spatial pattern of trapezius electromyographic activity in real and virtual environments.

    Directory of Open Access Journals (Sweden)

    Afshin Samani

    Full Text Available The design of an industrial workstation tends to include ergonomic assessment steps based on a digital mock-up and a virtual reality setup. Lack of interaction and system fidelity is often reported as a main issue in such virtual reality applications. This limitation is a crucial issue as thorough ergonomic analysis is required for an investigation of the biomechanics. In the current study, we investigated the biomechanical responses of the shoulder joint in a simulated assembly task for comparison with the biomechanical responses in virtual environments. Sixteen male healthy novice subjects performed the task on three different platforms: real (RE, virtual (VE, and virtual environment with force feedback (VEF with low and high precision demands. The subjects repeated the task 12 times (i.e., 12 cycles. High density electromyography from the upper trapezius and rotation angles of the shoulder joint were recorded and split into the cycles. The angular trajectories and velocity profiles of the shoulder joint angles over a cycle were computed in 3D. The inter-subject similarity in terms of normalized mutual information on kinematics and electromyography was investigated. Compared with RE the task in VE and VEF was characterized by lower kinematic maxima. The inter-subject similarity in RE compared with intra-subject similarity across the platforms was lower in terms of movement trajectories and greater in terms of trapezius muscle activation. The precision demand resulted in lower inter- and intra-subject similarity across platforms. The proposed approach identifies biomechanical differences in the shoulder joint in both VE and VEF compared with the RE platform, but these differences are less marked in VE mostly due to technical limitations of co-localizing the force feedback system in the VEF platform.

  17. Wearing a safety harness during treadmill walking influences lower extremity kinematics mainly through changes in ankle regularity and local stability

    Directory of Open Access Journals (Sweden)

    Decker Leslie M

    2012-02-01

    Full Text Available Abstract Background Wearing a harness during treadmill walking ensures the subject's safety and is common practice in biomedical engineering research. However, the extent to which such practice influences gait is unknown. This study investigated harness-related changes in gait patterns, as evaluated from lower extremity kinematics during treadmill walking. Findings Healthy subjects (n = 10 walked on a treadmill at their preferred speed for 3 minutes with and without wearing a harness (LiteGait®, Mobility Research, Inc.. In the former condition, no weight support was provided to the subjects. Lower extremity kinematics was assessed in the sagittal plane from the mean (meanRoM, standard deviation (SDRoM and coefficient of variation (CoVRoM of the hip, knee, and ankle ranges of motion (RoM, as well as from the sample entropy (SampEn and the largest Lyapunov exponent (LyE of the joints' angles. Wearing the harness increased the meanRoM of the hip, the SDRoM and the CoVRoM of the knee, and the SampEn and the LyE of the ankle. In particular, the harness effect sizes for both the SampEn and the LyE of the ankle were large, likely reflecting a meaningful decline in the neuromuscular stabilizing control of this joint. Conclusions Wearing a harness during treadmill walking marginally influences lower extremity kinematics, resulting in more or less subtle changes in certain kinematic variables. However, in cases where differences in gait patterns would be expressed through modifications in these variables, having subjects walk with a harness may mask or reinforce such differences.

  18. Anodal transcranial direct current stimulation to the cerebellum improves handwriting and cyclic drawing kinematics in focal hand dystonia.

    Science.gov (United States)

    Bradnam, Lynley V; Graetz, Lynton J; McDonnell, Michelle N; Ridding, Michael C

    2015-01-01

    There is increasing evidence that the cerebellum has a role in the pathophysiology of primary focal hand dystonia and might provide an intervention target for non-invasive brain stimulation to improve function of the affected hand. The primary objective of this study was to determine if cerebellar transcranial direct current stimulation (tDCS) improves handwriting and cyclic drawing kinematics in people with hand dystonia, by reducing cerebellar-brain inhibition (CBI) evoked by transcranial magnetic stimulation (TMS). Eight people with dystonia (5 writer's dystonia, 3 musician's dystonia) and eight age-matched controls completed the study and underwent cerebellar anodal, cathodal and sham tDCS in separate sessions. Dystonia severity was assessed using the Writer's Cramp Rating Scale (WRCS) and the Arm Dystonia Disability Scale (ADDS). The kinematic measures that differentiated the groups were; mean stroke frequency during handwriting and fast cyclic drawing and average pen pressure during light cyclic drawing. TMS measures of cortical excitability were no different between people with FHD and controls. There was a moderate, negative relationship between TMS-evoked CBI at baseline and the WRCS in dystonia. Anodal cerebellar tDCS reduced handwriting mean stroke frequency and average pen pressure, and increased speed and reduced pen pressure during fast cyclic drawing. Kinematic measures were not associated with a decrease in CBI within an individual. In conclusion, cerebellar anodal tDCS appeared to improve kinematics of handwriting and circle drawing tasks; but the underlying neurophysiological mechanism remains uncertain. A study in a larger homogeneous population is needed to further investigate the possible therapeutic benefit of cerebellar tDCS in dystonia.

  19. Soft tissue artifact compensation in knee kinematics by multi-body optimization: Performance of subject-specific knee joint models.

    Science.gov (United States)

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

    2015-11-05

    Soft tissue artifact (STA) distort marker-based knee kinematics measures and make them difficult to use in clinical practice. None of the current methods designed to compensate for STA is suitable, but multi-body optimization (MBO) has demonstrated encouraging results and can be improved. The goal of this study was to develop and validate the performance of knee joint models, with anatomical and subject-specific kinematic constraints, used in MBO to reduce STA errors. Twenty subjects were recruited: 10 healthy and 10 osteoarthritis (OA) subjects. Subject-specific knee joint models were evaluated by comparing dynamic knee kinematics recorded by a motion capture system (KneeKG™) and optimized with MBO to quasi-static knee kinematics measured by a low-dose, upright, biplanar radiographic imaging system (EOS(®)). Errors due to STA ranged from 1.6° to 22.4° for knee rotations and from 0.8 mm to 14.9 mm for knee displacements in healthy and OA subjects. Subject-specific knee joint models were most effective in compensating for STA in terms of abduction-adduction, inter-external rotation and antero-posterior displacement. Root mean square errors with subject-specific knee joint models ranged from 2.2±1.2° to 6.0±3.9° for knee rotations and from 2.4±1.1 mm to 4.3±2.4 mm for knee displacements in healthy and OA subjects, respectively. Our study shows that MBO can be improved with subject-specific knee joint models, and that the quality of the motion capture calibration is critical. Future investigations should focus on more refined knee joint models to reproduce specific OA knee geometry and physiology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. On the kinematics of visual binary and multiple stars of the FK4 cataloque

    International Nuclear Information System (INIS)

    Starikova, G.A.

    1981-01-01

    Kinematic features of single, binary and multiple stars are considered. To compare kinematics of such stars with the kinematics of single stars the data on positions and proper motions of those stars which are given in the basic catalogue FK4. Single as well as visual binary and multiple stars united because of their limited content in FK4 have been subdivided by spectra and classes of luminosity into groups with account for known kinematic peculiarities of various spectral groups. Kinematic features for the studied spectral groups are given. By the stars of the FK4 catalogue for various spectral classes the difference of kinematic features of single, visual binary and multiple stars is obtained. However the values of these differences need to be specified due to small number of stars included in five of six groups considered