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
Analysis of particle kinematics in spheronization via particle image velocimetry.
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.
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.
Target Lagrangian kinematic simulation for particle-laden flows.
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.
Flow Kinematics and Particle Orientations during Composite Processing
International Nuclear Information System (INIS)
Chiba, Kunji
2007-01-01
The mechanism of orientation of fibers or thin micro-particles in various flows involving the processing of composite materials has not been fully understood although it is much significant to obtain the knowledge of the processing operations of particle reinforced composites as well as to improve the properties of the advanced composites. The objective of this paper is to introduce and well understand the evolution of the particle orientation in a suspension flow and flow kinematics induced by suspended particles by means of our two research work
Acceleration of particles by black holes: Kinematic explanation
International Nuclear Information System (INIS)
Zaslavskii, O. B.
2011-01-01
A new simple and general explanation of the effect of acceleration of particles by black holes to infinite energies in the center of mass frame is suggested. It is based on kinematics of particles moving near the horizon. This effect arises when particles of two kinds collide near the horizon. For massive particles, the first kind represents a particle with the generic energy and angular momentum (I call them ''usual''). Near the horizon, such a particle has a velocity almost equal to that of light in the frame that corotates with a black hole (the frame is static if a black hole is static). The second kind (called ''critical'') consists of particles with the velocity v< c near the horizon due to special relationship between the energy and angular momentum (or charge). As a result, the relative velocity approaches the speed of light c, and the Lorentz factor grows unbound. This explanation applies both to generic rotating black holes and charged ones (even for radial motion of particles). If one of the colliding particles is massless (photon), the critical particle is distinguished by the fact that its frequency is finite near the horizon. The existence (or absence) of the effect is determined depending on competition of two factors--gravitational blue shift for a photon propagating towards a black hole and the Doppler effect due to transformation from the locally nonrotating frame to a comoving one. Classification of all possible types of collisions is suggested depending on whether massive or massless particle is critical or usual.
Székely, Gergely
2012-01-01
Within an axiomatic framework of kinematics, we prove that the existence of faster than light particles is logically independent of Einstein's special theory of relativity. Consequently, it is consistent with the kinematics of special relativity that there might be faster than light particles.
About kinematics and hydrodynamics of spinning particles: some simple considerations
International Nuclear Information System (INIS)
Recami, Erasmo; Rodrigues Junior, Waldyr A.; Salesi, Giovanni
1995-12-01
In the first part (Sections 1 and 2) of this paper - starting from the Pauli current, in the ordinary tensorial language - we obtain the decomposition of the non-relativistic field velocity into two orthogonal parts: the classical part, that is the velocity w p/m of the center-of-mass (CM), and the so-called quantum part, that is, the velocity V of the motion in the CM frame (namely, the integral spin motion or Zitterbewegung). By inserting such a complete, composite expression of the velocity into the kinetic energy term of the non-relativistic classical (Newtonian) Lagrangian, we straightforwardly get the appearance of the so-called quantum potential associated, as it is know, with the Madelueng fluid. This result carries further evidence that the quantum behaviour of micro-systems can be a direct consequence of the fundamental existence of spin. In the second part (Sections 3 and 4), we fix our attention on the total velocity vector v vector w + vector V, being now necessary to pass to relativistic (classical) physics; and we show that the proper time entering the definition of the four-velocity v μ for spinning particles has to be the proper time τ of the CM frame. Inserting the correct Lorentz factor into the definition of v μ leads to completely new kinematical properties for v 2 . The important constraint pμ v μ identically true for scalar particles, but just assumed a priori in all previous spinning particle theories, is herein derived in a self-consistent way. (author). 24 refs
About kinematics and hydrodynamics of spinning particles: some simple considerations
Energy Technology Data Exchange (ETDEWEB)
Recami, Erasmo; Rodrigues Junior, Waldyr A. [Universidade Estadual de Campinas, SP (Brazil). Dept. de Matematica Aplicada; Salesi, Giovanni [Universita Statale di Catania (Italy). Dipt. di Fisica
1995-12-01
In the first part (Sections 1 and 2) of this paper - starting from the Pauli current, in the ordinary tensorial language - we obtain the decomposition of the non-relativistic field velocity into two orthogonal parts: the classical part, that is the velocity w p/m of the center-of-mass (CM), and the so-called quantum part, that is, the velocity V of the motion in the CM frame (namely, the integral spin motion or Zitterbewegung). By inserting such a complete, composite expression of the velocity into the kinetic energy term of the non-relativistic classical (Newtonian) Lagrangian, we straightforwardly get the appearance of the so-called quantum potential associated, as it is know, with the Madelueng fluid. This result carries further evidence that the quantum behaviour of micro-systems can be a direct consequence of the fundamental existence of spin. In the second part (Sections 3 and 4), we fix our attention on the total velocity vector v vector w + vector V, being now necessary to pass to relativistic (classical) physics; and we show that the proper time entering the definition of the four-velocity v{sup {mu}} for spinning particles has to be the proper time {tau} of the CM frame. Inserting the correct Lorentz factor into the definition of v{sup {mu}} leads to completely new kinematical properties for v{sup 2}. The important constraint p{mu} v{sup {mu}} identically true for scalar particles, but just assumed a priori in all previous spinning particle theories, is herein derived in a self-consistent way. (author). 24 refs.
Kinematics of flow and sediment particles at entrainment and deposition
Antico, Federica; Sanches, Pedro; Aleixo, Rui; Ferreira, Rui M. L.
2015-04-01
A cohesionless granular bed subjected to a turbulent open-channel flow is analysed. The key objective is to clarify the kinematics of entrainment and deposition of individual sediment particles. In particular, we quantify a) the turbulent flow field in the vicinity of particles at the instants of their entrainment and of their deposition; b) the initial particle velocity and the particle velocity immediately before returning to rest. The experimental work was performed at the Hydraulics Laboratory of IST-UL in a 12.5 m long, 0.405 m wide glass-walled flume recirculating water and sediment through independent circuits. The granular bed was a 4.0 m long and 2.5 cm deep reach filled with 5 mm diameter glass beads packed (with some vibration) to a void fraction of 0.356, typical of random packing. Upstream the mobile bed reach the bed was composed of glued particles to ensure the development of a boundary layer with the same roughness. Laboratory tests were run under conditions of weak beadload transport with Shields parameters in the range 0.007 to 0.03. Froude numbers ranged from 0.63 to 0.95 while boundary Reynolds numbers were in the range 130 to 300. It was observed that the bed featured patches of regular arrangements: face centered cubic (fcc) or hexagonal close packing (hcp) blocks alternate with and body centered cubic (bcc) blocks. The resulting bed surface exhibits cleavage lines between blocks and there are spatial variations of bed elevation. The option for artificial sediment allowed for a simplified description of particle positioning at the instant of entrainment. In particular support and pivoting angles are found analytically. Skin friction angles were determind experimentally. The only relevant variables are exposure (defined as the ratio of the actual frontal projection of the exposed area to the area of a circle with 5 mm diameter) and protrusion (defined as the vertical distance between the apex of the particle and the mean local bed elevation
Kinematical analysis of the data from three-particle reactions by statistical methods
International Nuclear Information System (INIS)
Krug, J.; Nocken, U.
1976-01-01
A statistical procedure to unfold the kinematics of coincidence spectra from three-particle reactions is presented which is used to protect the coincidence events on the kinematical curve. The width of the projection intervals automatically matches the experimental resolution.. The method is characterized by its consistency thus also permitting a reasonable projection of sum-coincidences. (Auth.)
International Nuclear Information System (INIS)
La Ville, J.L.; Bizard, G.; Durand, D.; Jin, G.M.; Rosato, E.
1990-06-01
Light fragment emission, when triggered by large transverse momentum protons shows specific kinematical correlations due to recoil effects of the excited emitting source. Such effects have been observed in azimuthal angular distributions of He-particles produced in collisions induced by 94 MeV/u 16 0 ions on Al, Ni and Au targets. A model calculation assuming a two-stage mechanism (formation and sequential decay of a hot source) gives a good description of these whole data. From this succesfull confrontation, it is possible to estimate the size of the emitting system
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 ...
On the calculation of the water particle kinematics arising in a directionally spread wavefield
Bateman, W J D; Taylor, P H
2003-01-01
This paper concerns the calculation of the water particle kinematics generated by the propagation of surface gravity waves. The motivation for this work lies in recent advances in the description of the water surface elevation associated with extreme waves that are highly nonlinear and involve a spread of wave energy in both frequency and direction. To provide these exact numerical descriptions the nonlinear free-surface boundary conditions are time-marched, with the most efficient solutions simply based upon the water surface elevation, eta, and the velocity potential, phi, on that surface. In many broad-banded problems, computational efficiency is not merely desirable but absolutely essential to resolve the complex interactions between wave components with widely varying length-scales and different directions of propagation. Although such models have recently been developed, the calculation of the underlying water particle kinematics, based on the surface properties alone, remains a significant obstacle to ...
International Nuclear Information System (INIS)
Pavlov, N N
2013-01-01
Penetration of solar energetic particles into the Earth's magnetosphere is quantitatively studied with a simple kinematic model. The goal is to assess, for the first time, how does effectiveness of the penetration depend on such geometry factors as: distance of the magneto-pause (MP) from the Earth; shape of MP; angle at which solar energetic particle crosses MP; location of the crossing point; type of the particle motion in the magnetosphere. To get off excessive details, the model deliberately operates with just equatorial section of the static dipolar magnetic field confined with asymmetric boundary – MP. Several rather obvious facts are illustrated: finite orbits of longitudinal drift reside only inside the circle of the Störmer-unit-length radius; deepest penetration of a particle occurs if the particle crosses MP at the point closest to the Earth and with velocity-vector oriented along the particle's longitudinal drift inside MP (westward for protons); etc. The model's software allows the inquirer to vary geometry of MP, the type, energy and direction of flight of the energetic particle(s), the location(s), aperture and orientation(s) of a virtual sensor, then to run the model and obtain the reference particle distributions either global (for entire magnetosphere) or for specified locations, all along the time, energy and flux-orientation axes. Static and animated plots can be easily produced. The model provides a toolkit allowing one to evaluate and illustrate the process of particle penetration into the magnetosphere under various conditions in space. It may be used for the configuring of the satellite particle sensors; its results may be compared with the observations for to assess how strongly the real magnetosphere differs from its simplified form; it may be used in education.
Koester, Martin; García, R Edwin; Thommes, Markus
2014-12-30
Spheronization is an important pharmaceutical manufacturing technique to produce spherical agglomerates of 0.5-2mm diameter. These pellets have a narrow size distribution and a spherical shape. During the spheronization process, the extruded cylindrical strands break in short cylinders and evolve from a cylindrical to a spherical state by deformation and attrition/agglomeration mechanisms. Using the discrete element method, an integrated modeling-experimental framework is presented, that captures the particle motion during the spheronization process. Simulations were directly compared and validated against particle image velocimetry (PIV) experiments with monodisperse spherical and dry γ-Al2O3 particles. demonstrate a characteristic torus like flow pattern, with particle velocities about three times slower than the rotation speed of the friction plate. Five characteristic zones controlling the spheronization process are identified: Zone I, where particles undergo shear forces that favors attrition and contributes material to the agglomeration process; Zone II, where the static wall contributes to the mass exchange between particles; Zone III, where gravitational forces combined with particle motion induce particles to collide with the moving plate and re-enter Zone I; Zone IV, where a subpopulation of particles are ejected into the air when in contact with the friction plate structure; and Zone V where the low poloidal velocity favors a stagnant particle population and is entirely controlled by the batch size. These new insights in to the particle motion are leading to deeper process understanding, e.g., the effect of load and rotation speed to the pellet formation kinetics. This could be beneficial for the optimization of a manufacturing process as well as for the development of new formulations. Copyright © 2014 Elsevier B.V. All rights reserved.
Kinematic algebras, groups for elementary particles, and the geometry of momentum space
International Nuclear Information System (INIS)
Izmest'ev, A.A.
1986-01-01
It is shown that to each n-dimensional (n≥2) homogeneous isotropic Riemannian momentum (coordinate) space there corresponds a definite kinematic local algebra of operators N/sub a/, M/sub a//sub b/, P/sub a//sub ,/ ω(a,b = 1,2,...,n). In the three-dimensional case this gives the possibility of classifying particles in accordance with the algebras of the types of momentum space. The approach developed also makes it possible to obtain generalized equations describing particles of the different types. The operators under consideration satisfy not only the relevant algebra but also relations independent of the algebra that coincide in form with the Maxwell equations
Detecting kinematic boundary surfaces in phase space: particle mass measurements in SUSY-like events
Debnath, Dipsikha; Gainer, James S.; Kilic, Can; Kim, Doojin; Matchev, Konstantin T.; Yang, Yuan-Pao
2017-06-01
We critically examine the classic endpoint method for particle mass determination, focusing on difficult corners of parameter space, where some of the measurements are not independent, while others are adversely affected by the experimental resolution. In such scenarios, mass differences can be measured relatively well, but the overall mass scale remains poorly constrained. Using the example of the standard SUSY decay chain \\tilde{q}\\to {\\tilde{χ}}_2^0\\to \\tilde{ℓ}\\to {\\tilde{χ}}_1^0 , we demonstrate that sensitivity to the remaining mass scale parameter can be recovered by measuring the two-dimensional kinematical boundary in the relevant three-dimensional phase space of invariant masses squared. We develop an algorithm for detecting this boundary, which uses the geometric properties of the Voronoi tessellation of the data, and in particular, the relative standard deviation (RSD) of the volumes of the neighbors for each Voronoi cell in the tessellation. We propose a new observable, \\overline{Σ} , which is the average RSD per unit area, calculated over the hypothesized boundary. We show that the location of the \\overline{Σ} maximum correlates very well with the true values of the new particle masses. Our approach represents the natural extension of the one-dimensional kinematic endpoint method to the relevant three dimensions of invariant mass phase space.
Kinematic shifts of β-delayed particles as a probe of β-ν angular correlations
International Nuclear Information System (INIS)
Clifford, E.T.H.; Azuma, R.E.; Jackson, K.P.; Koslowsky, V.T.; Hardy, J.C.; Schmeing, H.; Faestermann, T.; Schrewe, U.J.; Evans, H.C.; Hagberg, E.; Toronto Univ., Ontario; Queen's Univ., Kingston, Ontario
1981-01-01
Beta-delayed particles undergo a kinematic shift in energy due to recoil motion of the daughter nucleus following beta decay. A careful measurement of this energy shift can be used to establish the ratio of vector to axial vector components in beta transitions. Alpha-beta coincidence data for the beta-delayed alpha decay of 20 Na have been obtained. Component ratios for 6 transitions including the super-allowed branch were found. Limits on charge dependent mixing with the analogue state were deduced for 5 states in 20 Nesup(*). For the superallowed branch the axial vector component was found; the polar vector component was deduced and establishes a value for the vector weak coupling constant of Gsub(V) = (1.355 +- 0.036) x 10 -49 erg cm 3 . (orig.)
Kinematic shifts of beta -delayed particles as a probe of beta - nu angular correlations
Clifford, E T H; Evans, H C; Fästermann, T; Hagberg, E; Hardy, J C; Jackson, K P; Koslowsky, V T; Schmeing, H; Schrewe, U J
1981-01-01
Beta-delayed particles undergo a kinematic shift in energy due to recoil motion of the daughter nucleus following beta decay. A careful measurement of this energy shift can be used to establish the ratio of vector to axial vector components in beta transitions. Alpha-beta coincidence data for the beta-delayed alpha decay of /sup 20/Na have been obtained. Component ratios for 6 transitions including the superallowed branch are found. Limits on charge dependent mixing with the analogue state are deduced for 5 states in /sup 20/Ne*. For the superallowed branch the axial vector component is found; the polar vector component is deduced and establishes a value for the vector weak coupling constant of G/sub V/=(1.355+or-0.036)*10/sup -49/ erg cm /sup 3/. (13 refs).
International Nuclear Information System (INIS)
Mashood, K K; Singh, Vijay A
2012-01-01
Student difficulties regarding the angular velocity and angular acceleration of a particle have remained relatively unexplored in contrast to their linear counterparts. We present an inventory comprising multiple choice questions aimed at probing misconceptions and eliciting ill-suited reasoning patterns. The development of the inventory was based on interactions with students, teachers and experts. We report misconceptions, some of which are parallel to those found earlier in linear kinematics. Fixations with inappropriate prototypes were uncovered. Many students and even teachers mistakenly assume that all rotational motion is necessarily circular. A persistent notion that the direction of angular velocity and angular acceleration should be ‘along’ the motion exists. Instances of indiscriminate usage of equations were identified. (paper)
Directory of Open Access Journals (Sweden)
Yazhe Tang
2015-01-01
Full Text Available This paper presents a novel surveillance system named thermal omnidirectional vision (TOV system which can work in total darkness with a wild field of view. Different to the conventional thermal vision sensor, the proposed vision system exhibits serious nonlinear distortion due to the effect of the quadratic mirror. To effectively model the inherent distortion of omnidirectional vision, an equivalent sphere projection is employed to adaptively calculate parameterized distorted neighborhood of an object in the image plane. With the equivalent projection based adaptive neighborhood calculation, a distortion-invariant gradient coding feature is proposed for thermal catadioptric vision. For robust tracking purpose, a rotational kinematic modeled adaptive particle filter is proposed based on the characteristic of omnidirectional vision, which can handle multiple movements effectively, including the rapid motions. Finally, the experiments are given to verify the performance of the proposed algorithm for human tracking in TOV system.
Debnath, Dipsikha; Kilic, Can; Kim, Doojin; Matchev, Konstantin T.; Yang, Yuan-Pao
2017-06-19
We critically examine the classic endpoint method for particle mass determination, focusing on difficult corners of parameter space, where some of the measurements are not independent, while others are adversely affected by the experimental resolution. In such scenarios, mass differences can be measured relatively well, but the overall mass scale remains poorly constrained. Using the example of the standard SUSY decay chain $\\tilde q\\to \\tilde\\chi^0_2\\to \\tilde \\ell \\to \\tilde \\chi^0_1$, we demonstrate that sensitivity to the remaining mass scale parameter can be recovered by measuring the two-dimensional kinematical boundary in the relevant three-dimensional phase space of invariant masses squared. We develop an algorithm for detecting this boundary, which uses the geometric properties of the Voronoi tessellation of the data, and in particular, the relative standard deviation (RSD) of the volumes of the neighbors for each Voronoi cell in the tessellation. We propose a new observable, $\\bar\\Sigma$, which is ...
Collective behaviour of self-propelling particles with conservative kinematic constraints
Ratushna, Valeriya Igorivna
2007-01-01
In this thesis I considered the dynamics of self-propelling particles (SPP). Flocking of living organisms like birds, fishes, ants, bacteria etc. is an area where the theory of the collective behaviour of SPP can be applied. One can often see how these animals develop coherent motion, amazing the
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
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.
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
International Nuclear Information System (INIS)
Berezin, F.N.; Kisurin, V.A.; Nemets, O.F.; Ofengenden, R.G.; Pugach, V.M.; Pavlenko, Yu.N.; Patlan', Yu.V.; Savrasov, S.S.
1981-01-01
Experimental technique for investigation of three-particle nuclear reactions in kinematically total experiments is described. The technique provides the storage of one-dimensional and two- dimensional energy spectra from several detectors. A block diagram of the measuring system, using this technique, is presented. The measuring system consists of analog equipment for rapid-slow coincidences and of a two-processor complex on the base of the M-400 computer with a general bus. Application of a two-processor complex, each computer of which has a possibility of direct access to memory of another computer, permits to separate functions of data collection and data operational presentation and to perform necessary physical calculations. Software of the measuring complex which includes programs written using the ASSEMBLER language for the first computer and functional programs written using the BASIC language for the second computer, is considered. Software of the first computer includes the DISPETCHER dialog control program, driver package for control of external devices, of applied program package and system modules. The technique, described, is tested in experiment on investigation of d+ 10 B→α+α+α three- particle reaction at deutron energy of 13.6 MeV. The two-dimensional energy spectrum reaction obtained with the help of the technique described is presented [ru
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 ...
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.
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.)
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.
Parallel kinematics type, kinematics, and optimal design
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...
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)
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.
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.
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....
Kinematic structures in galactic disc simulations
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
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
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.
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....
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.
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.)
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…
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
Quantum deformed magnon kinematics
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...
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.)
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
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
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.
Statics and kinematics of discrete Cosserat-type granular materials
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
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)
Weak Decays of Charmed Particles
Energy Technology Data Exchange (ETDEWEB)
Turcotte, Marc Gilles [McGill Univ., Montreal, QC (Canada)
1986-05-01
The lifetimes of charmed particles produced in interactions of high energy neutrinos with nucleons have been measured using a combination of a very high resolution emulsion-based vertex detector and a spectrometer allowing full kinematical reconstruction of the decays.
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)
Kinematic parameters of signed verbs.
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.
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
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
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.
Kinematic sensitivity of robot manipulators
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.
Latest Advances in Robot Kinematics
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.
Kinematics of machinery through hyperworks
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.
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
Ordered kinematic endpoints for 5-body cascade decays
Energy Technology Data Exchange (ETDEWEB)
Klimek, Matthew D. [Theory Group, Department of Physics and Texas Cosmology Center,University of Texas at Austin, 2515 Speedway, Stop C1608, Austin, TX, 78712 (United States)
2016-12-23
We present expressions for the kinematic endpoints of 5-body cascade decay chains proceeding through all possible combinations of 2-body and 3-body decays, with one stable invisible particle in the final decay stage. When an invariant mass can be formed in multiple ways by choosing different final state particles from a common vertex, we introduce techniques for finding the sub-leading endpoints for all indistinguishable versions of the invariant mass. In contrast to short decay chains, where sub-leading endpoints are linearly related to the leading endpoints, we find that in 5-body decays, they provide additional independent constraints on the mass spectrum.
Inverse Kinematics With Closed Form Solution For Denso Robot Manipulator
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...
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.
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.
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.
Pythagoras Theorem and Relativistic Kinematics
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.
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.
On transformation shear of precipitated zirconia particles
International Nuclear Information System (INIS)
Zhang, J.M.; Lam, K.Y.
1993-01-01
A model is proposed to investigate the transformation shear of the precipitated zirconia particles which undergo a stress-induced lattice transformation from tetragonal to monoclinic symmetry. Kinematically admissible twinning planes and the corresponding twinning elements are determined according to the continuum theory of dispacive phase transformation. It is postulated that only one twinning mode prevails in each transformed particle and that the minimization of elastic strain energy change dictates the morphology of the transformed variants. The transformation shear is determined by the twinning mode and the volume fraction of the corresponding variant. Numerical calculations show that each of the six kinematically admissible twinning modes may be kinematically favorable and therefore operate in constrained particle. The actual transformation shear in a transformed particle is shown to be dependent on the transformation stress, on the particle shape as well as on the lattice orientation relative to the principal axes of the ellipsoidal particle
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)
A study of the interpretations of charm particle decays into three charged particles in NA16
International Nuclear Information System (INIS)
Moa, T.
1984-03-01
The variation of the kinematic fit probability as a function of the mass of the decaying particle is studied for all hypotheses tried for the three prong charged decays in the NA16 LECB-EHS experiment. (author)
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.
Kinematics Control and Analysis of Industrial Robot
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.
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
The brown dwarf kinematics project
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.
Kinematic correction for roller skewing
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.
Inverse kinematics of OWI-535 robotic arm
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...
Hexagon OPE resummation and multi-Regge kinematics
Energy Technology Data Exchange (ETDEWEB)
Drummond, J.M. [School of Physics & Astronomy, University of Southampton,Highfield, Southampton, SO17 1BJ (United Kingdom); Theory Division, Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); LAPTh, CNRS, Université de Savoie,9 Chemin de Bellevue, F-74941 Annecy-le-Vieux Cedex (France); Papathanasiou, G. [LAPTh, CNRS, Université de Savoie,9 Chemin de Bellevue, F-74941 Annecy-le-Vieux Cedex (France)
2016-02-29
We analyse the OPE contribution of gluon bound states in the double scaling limit of the hexagonal Wilson loop in planar N=4 super Yang-Mills theory. We provide a systematic procedure for perturbatively resumming the contributions from single-particle bound states of gluons and expressing the result order by order in terms of two-variable polylogarithms. We also analyse certain contributions from two-particle gluon bound states and find that, after analytic continuation to the 2→4 Mandelstam region and passing to multi-Regge kinematics (MRK), only the single-particle gluon bound states contribute. From this double-scaled version of MRK we are able to reconstruct the full hexagon remainder function in MRK up to five loops by invoking single-valuedness of the results.
Quantifying meniscal kinematics in dogs.
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.
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.
Ballistic representation for kinematic access
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.
Bat flight: aerodynamics, kinematics and flight morphology.
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.
Relativistic kinematics and dynamics: a new group theoretical approach
International Nuclear Information System (INIS)
Giovannini, N.
1983-01-01
The author reanalyzes the relationships between physical states and space-time symmetries with a view to describing relativistic extended and interacting systems. For this description he proposes to introduce, in space-time, an additional observable, related to a natural notion of simultaneity. The introduction of this new observable is justified on the basis of the operational meaning of the relations between state descriptions and symmetries in this case. The Poincare transformations are correspondingly split into two parts: the first one, kinematical, related to the symmetries of the description of the states, the other one, dynamical, related to the possible forms for the evolution. It is shown that the kinematical symmetries lead in a straightforward way to the expected classical and quantal state spaces for single particles of arbitrary spin and the author shows how the remaining symmetries can be related to the derivation of the possible forms for the dynamics. He finds as a particular case the usual dynamics of single particles in external fields (with some satisfactory improvements due to the corresponding new interpretation) and extends the method to the dynamics of N interacting particles. He also shows why this new approach and interpretation of relativistic states is necessary and how it allows a covariant description in the problems raised by the (recently measured) quantum correlations at-a-distance concerning the Einstein-Podolsky-Rosen paradox, something which seems quite impossible in the usual frameworks. (Auth.)
Kinematics of relative motion of test particles in general relativity
International Nuclear Information System (INIS)
Bazanski, S.L.
1977-01-01
A detailed mathematical study of the concept of geodesic deviation in pseudo-riemannian geometry is presented. A generalization of this concept to geodesic deviations of a higher order is then introduced and the second geodesic deviation is investigated in some detail. A geometric interpretation of the set of generalized geodesic deviations is given and applied in general relativity to determine a covariant and local description (with a desired order of accuracy) of test motions which take place in a certain finite neighbourhood of a given world line of an observer. The proper time evolution of two other objects related to geodesic deviation is also discussed: the space separation vector and the telescopic vector. This last name is given here to a field of null vectors along observer's world line which always point towards the same adjacent world line. The telescopic equations allow to determine the evolution of the frequency shift of electromagnetic radiation sent from and received on neighbouring world lines. On the basis of these equations also certain relations have been derived which connect the frequencies or frequency shifts with the curvature of space-time
Tune-shift with amplitude due to nonlinear kinematic effect
Wan, W
1999-01-01
Tracking studies of the Muon Collider 50 on 50 GeV collider ring show that the on-momentum dynamic aperture is limited to around 10 sigma even with the chromaticity sextupoles turned off. Numerical results from the normal form algorithm show that the tune-shift with amplitude is surprisingly large. Both analytical and numerical results are presented to show that nonlinear kinematic effect originated from the large angles of particles in the interaction region is responsible for the large tune-shift which in turn limits the dynamic aperture. A comparative study of the LHC collider ring is also presented to demonstrate the difference between the two machines. (14 refs).
Kinematically Decoupled Cores in Dwarf (Elliptical) Galaxies
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
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
Investigating The Kinematics of Canids and Felids
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.
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.
The kinematical AdS{sub 5}×S{sup 5} Neumann coefficient
Energy Technology Data Exchange (ETDEWEB)
Bajnok, Zoltan [MTA Lendület Holographic QFT Group, Wigner Research Centre,P.O.B. 49, Budapest 114, H-1525 (Hungary); Janik, Romuald A. [Institute of Physics, Jagiellonian University,ul. Łojasiewicza 11, Kraków, 30-348 (Poland)
2016-02-22
For the case of two particles a solution of the string field theory vertex axioms can be factorized into a standard form factor and a kinematical piece which includes the dependence on the size of the third string. In this paper we construct an exact solution of the kinematical axioms for AdS{sub 5}×S{sup 5} which includes all order wrapping corrections w.r.t. the size of the third string. This solution is expressed in terms of elliptic Gamma functions and ordinary elliptic functions. The solution is valid at any coupling and we analyze its weak coupling, pp-wave and large L limit.
Robot Kinematics, using Dual Quaternions
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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.
A Soft Parallel Kinematic Mechanism.
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.
Surface growth kinematics via local curve evolution
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
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.
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
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
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.
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
Chiral quark model with relativistic kinematics
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.
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.
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.
Kinematic gait analyses in healthy Golden Retrievers
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,...
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.
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
Inverse kinematic-based robot control
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.
Kinematically Optimal Robust Control of Redundant Manipulators
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.
Thin Layer Sensory Cues Affect Antarctic Krill Swimming Kinematics
True, A. C.; Webster, D. R.; Weissburg, M. J.; Yen, J.
2013-11-01
A Bickley jet (laminar, planar free jet) is employed in a recirculating flume system to replicate thin shear and phytoplankton layers for krill behavioral assays. Planar laser-induced fluorescence (LIF) and particle image velocimetry (PIV) measurements quantify the spatiotemporal structure of the chemical and free shear layers, respectively, ensuring a close match to in situ hydrodynamic and biochemical conditions. Path kinematics from digitized trajectories of free-swimming Euphausia superba examine the effects of hydrodynamic sensory cues (deformation rate) and bloom level phytoplankton patches (~1000 cells/mL, Tetraselamis spp.) on krill behavior (body orientation, swimming modes and kinematics, path fracticality). Krill morphology is finely tuned for receiving and deciphering both hydrodynamic and chemical information that is vital for basic life processes such as schooling behaviors, predator/prey, and mate interactions. Changes in individual krill behavior in response to ecologically-relevant sensory cues have the potential to produce population-scale phenomena with significant ecological implications. Krill are a vital trophic link between primary producers (phytoplankton) and larger animals (seabirds, whales, fish, penguins, seals) as well as the subjects of a valuable commercial fishery in the Southern Ocean; thus quantifying krill behavioral responses to relevant sensory cues is an important step towards accurately modeling Antarctic ecosystems.
... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution — ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...
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...
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
Tibial rotation kinematics subsequent to knee arthroplasty
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
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.
Interplanetary stream magnetism: Kinematic effects
International Nuclear Information System (INIS)
Burlaga, L.F.; Barouch, E.
1976-01-01
The particle density, and the magnetic field intensity and direction, are calculated for volume elements of the solar wind as a function of the initial magnetic field direction, Phi 0 , and the initial speed gradient, (deltaV/deltaR) 0 . It is assumed that the velocity is constant and radial. These assumptions are approximately valid between approx.0.1 and 1.0 AU for many streams. Time profiles of n, B, and V are calculated for corotating streams, neglecting effects of pressure gradients. The compression and rarefaction of B depend sensitively on Phi 0 . By averaging over a typical stream, it is found that approx.r -2 , whereas does not vary in a simple way, consistent with deep space observations. Changes of field direction may be very large, depending on the initial angle; but when the initial angle at 0.1 Au is such that the base of the field line corotates with the Sun, the spiral angle is the preferred direction at 1 AU. The theory is also applicable to nonstationary flows
Circadian rhythms in handwriting kinematics and legibility
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
Assessment of multi class kinematic wave models
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
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
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.
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
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
The kinematics of machinery outlines of a theory of machines
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.
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.
The Maiden Voyage of a Kinematics Robot
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).
Kinematic Optimization in Birds, Bats and Ornithopters
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.
Validation and Structural Analysis of the Kinematics Concept Test
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…
Lagrangian approach to understanding the origin of the gill-kinematics switch in mayfly nymphs.
Chabreyrie, R; Balaras, E; Abdelaziz, K; Kiger, K
2014-12-01
The mayfly nymph breathes under water through an oscillating array of plate-shaped tracheal gills. As the nymph grows, the kinematics of these gills change abruptly from rowing to flapping. The classical fluid dynamics approach to consider the mayfly nymph as a pumping device fails in giving clear reasons for this switch. In order to shed some light on this switch between the two distinct kinematics, we analyze the problem under a Lagrangian viewpoint. We consider that a good Lagrangian transport that effectively distributes and stirs water and dissolved oxygen between and around the gills is the main goal of the gill motion. Using this Lagrangian approach, we are able to provide possible reasons behind the observed switch from rowing to flapping. More precisely, we conduct a series of in silico mayfly nymph experiments, where body shape, as well as gill shapes, structures, and kinematics are matched to those from in vivo. In this paper, we show both qualitatively and quantitatively how the change of kinematics enables better attraction, confinement, and stirring of water charged of dissolved oxygen inside the gills area. We reveal the attracting barriers to transport, i.e., attracting Lagrangian coherent structures, that form the transport skeleton between and around the gills. In addition, we quantify how well the fluid particles are stirred inside the gills area, which by extension leads us to conclude that it will increase the proneness of molecules of dissolved oxygen to be close enough to the gills for extraction.
Reconstruction of the parameters of V0 particles
International Nuclear Information System (INIS)
Ierusalimov, A.P.
2009-01-01
The procedure of reconstruction of the parameters of V 0 particles is considered for CBM setup that is planned to build up at the FAIR complex (GSI, Germany). It was shown that the use of various kinematic cuts permits one to improve essentially the selection of V 0 particles and to increase the signal/background ratio. The use of the kinematic fit procedure gives still more considerable improvement of the accuracy of V 0 parameters. The procedure of the selection of Ξ - hyperons is also examined. The considered algorithm can be used practically without changes to reconstruct the parameters of V 0 particles and Ω - /Ξ - hyperons in MPD/NICA
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.)
Inelastic Proton Scattering on 21Na in Inverse Kinematics
Austin, Roby
2009-10-01
R.A.E. Austin, R. Kanungo, S. Reeve, Saint Mary's University; D.G. Jenkins, C.Aa.Diget, A. Robinson, A.G. Tuff, O. Roberts, University of York, UK; P.J. Woods, T. Davinson, G. J. Lotay, University of Edinburgh; C.-Y. Wu, Lawrence Livermore National Laboratory; H. Al Falou, G.C. Ball, M. Djongolov, A. Garnsworthy, G. Hackman, J.N. Orce, C.J. Pearson, S. Triambak, S.J. Williams, TRIUMF; C. Andreiou, D.S. Cross, N. Galinski, R. Kshetri, Simon Fraser University; C. Sumithrarachchi, M.A. Schumaker, University of Guelph; M.P. Jones, S.V. Rigby, University of Liverpool; D. Cline, A. Hayes, University of Rochester; T.E. Drake, University of Toronto; We describe an experiment and associated technique [1] to measure resonances of interest in astrophysical reactions. At the TRIUMF ISAC-II radioactive beam accelerator facility in Canada, particles inelastically scattered in inverse kinematics are detected with Bambino, a δE-E silicon telescope spanning 15-40 degrees in the lab. We use the TIGRESS to detect gamma rays in coincidence with the charged particles to cleanly select inelastic scattering events. We measured resonances above the alpha threshold in ^22Mg of relevance to the rate of break-out from the hot-CNO cycle via the reaction ^ 18Ne(α,p)^21Na. [1] PJ Woods et al. Rex-ISOLDE proposal 424 Cern (2003).
Surface growth kinematics via local curve evolution
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.
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)
Kinematics of the symbiotic system R Aqr
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.
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)
The kinematic advantage of electric cars
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.
Directed Neutron Beams From Inverse Kinematic Reactions
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.
6th International Workshop on Computational Kinematics
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).
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.
Analyzing Robotic Kinematics Via Computed Simulations
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.
Kinematics of Hooke universal joint robot wrists
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.
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.
Kinematics of Laying an Automated Weapon System
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
Kinematical Test Theories for Special Relativity
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.
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)
Circadian rhythms in handwriting kinematics and legibility.
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.
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.
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
Color-Kinematics Duality for QCD Amplitudes
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...
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
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)
Anomalous separation of homogeneous particle-fluid mixtures: Further observations
Husain, H. S.; Hussain, F.; Goldshtik, M.
1995-11-01
Previously, we reported the puzzling phenomenon of separation of components from an initially uniform mixture (air and smoke) in a rotating flow device (a cylindrical can with a rotating end disk). Here we summarize further studies of this phenomenon through experiments, analysis of particle forces, and direct numerical simulation (DNS). Separation of spherical polystyrene particles when immersed in water or pure alcohol lends further credence to the phenomenon. We have studied the dependence of the particle-free column size and its establishment time on particle size, particle concentration, disk and cylinder Reynolds numbers, and fluid composition. The evolution of passive markers in DNS shows segregation similar to that observed in experiments, supporting our kinematic separation hypothesis. However, kinematic action, though important, is inadequate to explain the ``antidiffusion'' phenomenon. Although estimates show that known particle forces cannot account for the particle separation, experimental results suggest the action of a yet unknown lift force whose effect is magnified kinematically in our apparatus. At high particle concentrations or when a small amount of solute (e.g. sugar, salt, or alcohol) is added to water polystyrene particle mixtures, the flow within the column becomes unstable and the particle-free column loses its axial symmetry; this unusual behavior is not yet clearly understood.
Integral equations for four identical particles in angular momentum representation
International Nuclear Information System (INIS)
Kharchenko, V.F.; Shadchin, S.A.
1975-01-01
In integral equations of motion for a system of four identical spinless particles with central pair interactions, transition is realized from the representation of relative Jacobi momenta to the representation of their moduli and relative angular moments. As a result, the variables associated with the rotation of the system as a whole are separated in the equations. The integral equations of motion for four particles are reduced to the form of an infinite system of three-demensional integral equations. The four-particle kinematic factors contained in integral kernels are expressed in terms of three-particle type kinematic factors. In the case of separable two-particle interaction, the equations of motion for four particles have the form of an infinite system of two-dimensional integral equations
A Novel Algorithm for the Generation of Distinct Kinematic Chain
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.
Kinematic control of robot with degenerate wrist
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.
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
Theory of gearing kinematics, geometry, and synthesis
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
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
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
Kinematic reversal schemes for the geomagnetic dipole.
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.
Kinematics of the CSE in VY CMa
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.
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.
Shoulder and Scapular Kinematics during the Windmill Softball Pitch
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...
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.
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...
Rigid-body kinematics versus flapping kinematics of a flapping wing micro air vehicle
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
International Nuclear Information System (INIS)
Powell, Andrew
2010-01-01
Particle identification (PID) is a fundamental requirement for LHCb and is provided by CALO, MUON and RICH sub-detectors. The Calorimeters provide identification of electrons, photons and hadrons in addition to the measurement of their energies and positions. As well as being part of the LHCb trigger, the MUON system provides identification of muons to a very high level of purity, essential for many CP-sensitive measurements that have J/ψ's in their final states. Hadron identification, in particular the ability to distinguish kaons and pions, is crucial to many LHCB analyses, particularly where the final states of interest are purely hadronic. The LHCb RICH system provides this, covering a momentum range between 1 and 100 GeV/c. To maintain the integrity of the LHCb physics performance, it is essential to measure and monitor the particle identification efficiency and mis-identification fraction over time. This can be done by using specific decays, such as K-shorts, φ's, Λ's, J/ψ's and D*'s, for which pure samples can be isolated using only kinematic quantities, due to their unique decay topologies. This allows for clean samples of known particle types to be selected, which can then be used to calibrate and monitor the PID performance from data. The procedures for performing this will be presented, together with preliminary results from the 2009 and 2010 LHC runs. (author)
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
The Pleiades apex and its kinematical structure
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.
International Nuclear Information System (INIS)
Kutschera, W.
1984-01-01
The use of Accelerator Mass Spectrometry (AMS) to search for hypothetical particles and known particles of rare processes is discussed. The hypothetical particles considered include fractionally charged particles, anomalously heavy isotopes, and superheavy elements. The known particles produced in rare processes discussed include doubly-charged negative ions, counting neutrino-produced atoms in detectors for solar neutrino detection, and the spontaneous emission of 14 C from 223 Ra. 35 references
P, C and T: Different Properties on the Kinematical Level
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].
Dispersion modeling by kinematic simulation: Cloud dispersion model
International Nuclear Information System (INIS)
Fung, J C H; Perkins, R J
2008-01-01
A new technique has been developed to compute mean and fluctuating concentrations in complex turbulent flows (tidal current near a coast and deep ocean). An initial distribution of material is discretized into any small clouds which are advected by a combination of the mean flow and large scale turbulence. The turbulence can be simulated either by kinematic simulation (KS) or direct numerical simulation. The clouds also diffuse relative to their centroids; the statistics for this are obtained from a separate calculation of the growth of individual clouds in small scale turbulence, generated by KS. The ensemble of discrete clouds is periodically re-discretized, to limit the size of the small clouds and prevent overlapping. The model is illustrated with simulations of dispersion in uniform flow, and the results are compared with analytic, steady state solutions. The aim of this study is to understand how pollutants disperses in a turbulent flow through a numerical simulation of fluid particle motion in a random flow field generated by Fourier modes. Although this homogeneous turbulent is rather a 'simple' flow, it represents a building block toward understanding pollutant dispersion in more complex flow. The results presented here are preliminary in nature, but we expect that similar qualitative results should be observed in a genuine turbulent flow.
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.
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.
Directory of Open Access Journals (Sweden)
S. Bagchi
2015-12-01
Full Text Available The Isoscalar Giant Monopole Resonance (ISGMR and the Isoscalar Giant Dipole Resonance (ISGDR compression modes have been studied in the doubly-magic unstable nucleus 56Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50 MeV/u with the MAYA active target at the GANIL facility. The centroid of the ISGMR has been obtained at Ex=19.1±0.5 MeV. Evidence for the low-lying part of the ISGDR has been found at Ex=17.4±0.7 MeV. The strength distribution for the dipole mode shows similarity with the prediction from the Hartree–Fock (HF based random-phase approximation (RPA [1]. These measurements confirm inelastic α-particle scattering as a suitable probe for exciting the ISGMR and the ISGDR modes in radioactive isotopes in inverse kinematics.
A new recoil distance technique using low energy coulomb excitation in inverse kinematics
Energy Technology Data Exchange (ETDEWEB)
Rother, W., E-mail: wolfram.rother@googlemail.com [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Dewald, A.; Pascovici, G.; Fransen, C.; Friessner, G.; Hackstein, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Ilie, G. [Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520 (United States); National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest-Magurele (Romania); Iwasaki, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Jolie, J. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Melon, B. [Dipartimento di Fisica, Universita di Firenze and INFN Sezione di Firenze, Sesto Fiorentino (Firenze) I-50019 (Italy); Petkov, P. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); INRNE-BAS, Sofia (Bulgaria); Pfeiffer, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Pissulla, Th. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Bundesumweltministerium, Robert-Schuman-Platz 3, D - 53175 Bonn (Germany); Zell, K.-O. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Jakobsson, U.; Julin, R.; Jones, P.; Ketelhut, S.; Nieminen, P.; Peura, P. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland); and others
2011-10-21
We report on the first experiment combining the Recoil Distance Doppler Shift technique and multistep Coulomb excitation in inverse kinematics at beam energies of 3-10 A MeV. The setup involves a standard plunger device equipped with a degrader foil instead of the normally used stopper foil. An array of particle detectors is positioned at forward angles to detect target-like recoil nuclei which are used as a trigger to discriminate against excitations in the degrader foil. The method has been successfully applied to measure lifetimes in {sup 128}Xe and is suited to be a useful tool for experiments with radioactive ion beams.
High energy production of gluons in a quasi-multi-Regge kinematics
International Nuclear Information System (INIS)
Fadin, V.S.; Lipatov, L.N.
1989-01-01
Inelastic gluon-gluon scattering amplitudes in the Born approximation for the quasi-multi-Regge kinematics are calculated, starting with the Veneziano-type expression for the inelastic amplitude of the gluon-tachyon scattering with its subsequent simplification in the region of large energies and the Regge slope α'→0. Results obtained allow one to determine the high order corrections to the gluon Regge trajectory, the reggeon-particle vertices and to the integral kernel of the Bethe-Salpeter equation for the vacuum t-channel partial waves. 10 refs.; 7 figs
Monitoring diver kinematics with dielectric elastomer sensors
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
Force generation of bio-inspired hover kinematics
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,
A School Experiment in Kinematics: Shooting from a Ballistic Cart
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…
Kinematic and neuromuscular relationships between lower extremity clinical movement assessments.
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.
Kinematic and Dynamic Analysis of a Lower Limb Exoskeleton
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.
Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease
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…
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.
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, ...
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.)
Forward and inverse kinematics of double universal joint robot wrists
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.
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.
21st Century Kinematics : The 2012 NSF Workshop
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...
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)
The Kinematic Learning Model using Video and Interfaces Analysis
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.
2nd Conference on Interdisciplinary Applications in Kinematics
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...
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...
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
Differential Kinematics Of Contemporary Industrial Robots
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
Kinematics gait disorder in men with fibromyalgia.
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.
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.
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.
SPACEBAR: Kinematic design by computer graphics
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.
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
Assessment of representational competence in kinematics
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
Synthetic tsunami waveform catalogs with kinematic constraints
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.
Simple Kinematic Pathway Approach (KPA) to Catchment-scale Travel Time and Water Age Distributions
Soltani, S. S.; Cvetkovic, V.; Destouni, G.
2017-12-01
The distribution of catchment-scale water travel times is strongly influenced by morphological dispersion and is partitioned between hillslope and larger, regional scales. We explore whether hillslope travel times are predictable using a simple semi-analytical "kinematic pathway approach" (KPA) that accounts for dispersion on two levels of morphological and macro-dispersion. The study gives new insights to shallow (hillslope) and deep (regional) groundwater travel times by comparing numerical simulations of travel time distributions, referred to as "dynamic model", with corresponding KPA computations for three different real catchment case studies in Sweden. KPA uses basic structural and hydrological data to compute transient water travel time (forward mode) and age (backward mode) distributions at the catchment outlet. Longitudinal and morphological dispersion components are reflected in KPA computations by assuming an effective Peclet number and topographically driven pathway length distributions, respectively. Numerical simulations of advective travel times are obtained by means of particle tracking using the fully-integrated flow model MIKE SHE. The comparison of computed cumulative distribution functions of travel times shows significant influence of morphological dispersion and groundwater recharge rate on the compatibility of the "kinematic pathway" and "dynamic" models. Zones of high recharge rate in "dynamic" models are associated with topographically driven groundwater flow paths to adjacent discharge zones, e.g. rivers and lakes, through relatively shallow pathway compartments. These zones exhibit more compatible behavior between "dynamic" and "kinematic pathway" models than the zones of low recharge rate. Interestingly, the travel time distributions of hillslope compartments remain almost unchanged with increasing recharge rates in the "dynamic" models. This robust "dynamic" model behavior suggests that flow path lengths and travel times in shallow
International Nuclear Information System (INIS)
Charpak, G.
2000-01-01
In this article G.Charpak presents the principles on which particle detection is based. Particle accelerators are becoming more and more powerful and require new detectors able to track the right particle in a huge flux of particles. The gigantic size of detectors in high energy physics is often due to the necessity of getting a long enough trajectory in a magnetic field in order to deduce from the curvature an accurate account of impulses in the reaction. (A.C.)
International Nuclear Information System (INIS)
Chinowsky, W.
1989-01-01
Work done in the mid 1950s at Brookhaven National Laboratory on strange particles is described. Experiments were done on the Cosmotron. The author describes his own and others' work on neutral kaons, lambda and theta particles and points out the theoretical gap between predictions and experimental findings. By the end of the decade, the theory of strange particles was better understood. (UK)
Particle interpretations of the PVLAS data
International Nuclear Information System (INIS)
Ringwald, A.
2007-04-01
Recently the PVLAS collaboration reported the observation of a rotation of linearly polarized laser light induced by a transverse magnetic field - a signal being unexpected within standard QED. In this review, we emphasize two mechanisms which have been proposed to explain this result: production of a single light neutral spin-zero particle or pair production of light minicharged particles. We discuss a class of models, involving, in addition to our familiar ''visible'' photon, further light ''hidden paraphotons'', which mix kinematically with the visible one, and further light paracharged particles. In these models, very strong astrophysical and cosmological bounds on the weakly interacting light particles mentioned above can be evaded. In the upcoming year, a number of decisive laboratory based tests of the particle interpretation of the PVLAS anomaly will be done. More generally, such experiments, exploiting high fluxes of low-energy photons and/or large electromagnetic fields, will dig into previously unconstrained parameter space of the above mentioned models. (orig.)
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.
Validation and structural analysis of the kinematics concept test
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.
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
Kinematic design considerations for minimally invasive surgical robots: an overview.
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.
Kinematical analysis with the Emulsion Cloud Chamber in the OPERA experiment
Di Capua, F
2010-01-01
The OPERA experiment aims at measuring for the first time neutrino oscil- lation in appearance mode through the detection of ni-tau in an almost pure niμ beam produced at CERN SPS (CNGS), 730 km far from the detector. The ni-tau appearance signal is identified through the measurement of the decay daughter particles of the " lepton produced in CC ni-tau interactions. Since the short-lived " particle has, at the energy of the beam, an average decay length shorter than a 1 mm, a micrometric detection resolution is needed. The OPERA appara- tus is hybrid, using nuclear emulsion as high precision tracker and electronic detectors for the time stamp, event localization in the target and muon recon- struction. The Emulsion Cloud Chamber technique fulfils the requirement of a microscopic resolution together with a large target mass. The kinematical analysis allowed by this technique is described.
Diphoton production at Tevatron in the quasi-multiple-Regge-kinematics approach
Energy Technology Data Exchange (ETDEWEB)
Saleev, V.A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Samarskij Gosudarstvennyj Univ., Samara (Russian Federation)
2009-12-15
We study the production of prompt diphotons in the central region of rapidity within the frame- work of the quasi-multi-Regge-kinematics approach applying the hypothesis of quark and gluon Reggeization. We describe accurately and without free parameters the experimental data which were obtained by the CDF Collaboration at the Tevatron Collider. It is shown that the main contribution to studied process is given by the direct fusion of two Reggeized gluons into a photon pair, which is described by the effective Reggeon-Reggeon to particle-particle vertex. The contribution from the annihilation of Reggeized quark-antiquark pair into a diphoton is also considered. At the stage of numerical calculations we use the Kimber-Martin-Ryskin prescription for unintegrated quark and gluon distribution functions, with the Martin-Roberts-Stirling-Thorne collinear parton densities for a proton as input. (orig.)
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
Evidence for α-particle condensation in nuclei from the Hoyle state deexcitation
International Nuclear Information System (INIS)
Raduta, Ad.R.; Borderie, B.; Geraci, E.; Le Neindre, N.; Napolitani, P.; Rivet, M.F.; Alba, R.; Amorini, F.; Cardella, G.; Chatterjee, M.; De Filippo, E.; Guinet, D.; Lautesse, P.; La Guidara, E.; Lanzalone, G.; Lanzano, G.; Lombardo, I.; Lopez, O.; Maiolino, C.; Pagano, A.
2011-01-01
The fragmentation of quasi-projectiles from the nuclear reaction 40 Ca + 12 C at 25 MeV/nucleon was used to produce excited states candidates to α-particle condensation. Complete kinematic characterization of individual decay events, made possible by a high-granularity 4π charged particle multi-detector, reveals that 7.5±4.0% of the particle decays of the Hoyle state correspond to direct decays in three equal-energy α-particles.
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)
An adaptive inverse kinematics algorithm for robot manipulators
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.
Kinetic theory of a longitudinally expanding system of scalar particles
International Nuclear Information System (INIS)
Epelbaum, Thomas; Gelis, François; Jeon, Sangyong; Moore, Guy; Wu, Bin
2015-01-01
A simple kinematical argument suggests that the classical approximation may be inadequate to describe the evolution of a system with an anisotropic particle distribution. In order to verify this quantitatively, we study the Boltzmann equation for a longitudinally expanding system of scalar particles interacting with a ϕ 4 coupling, that mimics the kinematics of a heavy ion collision at very high energy. We consider only elastic 2→2 scatterings, and we allow the formation of a Bose-Einstein condensate in overpopulated situations by solving the coupled equations for the particle distribution and the particle density in the zero mode. For generic CGC-like initial conditions with a large occupation number, the solutions of the full Boltzmann equation cease to display the classical attractor behavior sooner than expected; for moderate coupling, the solutions appear never to follow a classical attractor solution.
Symmetry, Wigner functions and particle reactions
International Nuclear Information System (INIS)
Chavlejshvili, M.P.
1994-01-01
We consider the great principle of physics - symmetry - and some ideas, connected with it, suggested by a great physicist Eugene Wigner. We will discuss the concept of symmetry and spin, study the problem of separation of kinematics and dynamics in particle reactions. Using Wigner rotation functions (reflecting symmetry properties) in helicity amplitude decomposition and crossing-symmetry between helicity amplitudes (which contains the same Wigner functions) we get convenient general formalism for description of reactions between particles with any masses and spins. We also consider some applications of the formalism. 17 refs., 1 tab
Energy Technology Data Exchange (ETDEWEB)
Raju, M.R.
1993-09-01
Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics.
International Nuclear Information System (INIS)
Raju, M.R.
1993-01-01
Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics
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
CERN. Geneva
2007-01-01
The understanding of the Universe at the largest and smallest scales traditionally has been the subject of cosmology and particle physics, respectively. Studying the evolution of the Universe connects today's large scales with the tiny scales in the very early Universe and provides the link between the physics of particles and of the cosmos. This series of five lectures aims at a modern and critical presentation of the basic ideas, methods, models and observations in today's particle cosmology.
International Nuclear Information System (INIS)
Kamal, Anwar
2014-01-01
Provides step-by-step derivations. Contains numerous tables and diagrams. Supports learning and teaching with numerous worked examples, questions and problems with answers. Sketches also the historical development of the subject. This textbook teaches particle physics very didactically. It supports learning and teaching with numerous worked examples, questions and problems with answers. Numerous tables and diagrams lead to a better understanding of the explanations. The content of the book covers all important topics of particle physics: Elementary particles are classified from the point of view of the four fundamental interactions. The nomenclature used in particle physics is explained. The discoveries and properties of known elementary particles and resonances are given. The particles considered are positrons, muon, pions, anti-protons, strange particles, neutrino and hadrons. The conservation laws governing the interactions of elementary particles are given. The concepts of parity, spin, charge conjugation, time reversal and gauge invariance are explained. The quark theory is introduced to explain the hadron structure and strong interactions. The solar neutrino problem is considered. Weak interactions are classified into various types, and the selection rules are stated. Non-conservation of parity and the universality of the weak interactions are discussed. Neutral and charged currents, discovery of W and Z bosons and the early universe form important topics of the electroweak interactions. The principles of high energy accelerators including colliders are elaborately explained. Additionally, in the book detectors used in nuclear and particle physics are described. This book is on the upper undergraduate level.
Chang, Manchium (Inventor); Colvin, Michael S. (Inventor)
1989-01-01
Magnetic polymer particles are formed by swelling porous, polymer particles and impregnating the particles with an aqueous solution of precursor magnetic metal salt such as an equimolar mixture of ferrous chloride and ferric chloride. On addition of a basic reagent such as dilute sodium hydroxide, the metal salts are converted to crystals of magnetite which are uniformly contained througout the pores of the polymer particle. The magnetite content can be increased and neutral buoyancy achieved by repetition of the impregnaton and neutralization steps to adjust the magnetite content to a desired level.
Global-local optimization of flapping kinematics in hovering flight
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.
Analytical kinematics analysis and synthesis of planar mechanisms
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.
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)
Relationship among shoulder proprioception, kinematics, and pain after stroke
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.
Global-local optimization of flapping kinematics in hovering flight
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.
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...
Overground-Propulsion Kinematics and Acceleration in Elite Wheelchair Rugby.
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.
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.
Kinematic power corrections in off-forward hard reactions.
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.
Inverse kinematics problem in robotics using neural networks
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.
Anatomical kinematic constraints: consequences on muscular forces and joint reactions
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 ...
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....
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
Kinematic control of redundant robots and the motion optimizability measure.
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.
Kinematic Chains in Ski Jumping In-run Posture.
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.
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.
Effect of suspension kinematic on 14 DOF vehicle model
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.
Twistor theory a particle-physicist attitude
International Nuclear Information System (INIS)
Perjes, Z.
1979-07-01
Particle models in twistor theory are reviewed, starting with an introduction into the kinematical-twistor formalism which describes massive particles in Minkowski space-time. The internal transformations of constituent twistors are then discussed. The quantization rules available from a study of twistor scattering situations are used to construct quantum models of fundamental particles. The theory allows the introduction of an internal space with a Kaehlerian metric where hadron structure is described by ''spherical'' states of bound constituents. It is conjectured that the spectrum of successive families of hadrons might approach an accumulation point in energy. Above this threshold energy, the Kaehlerian analog of ionization could occur wherein the zero-mass constituents (twistors) of the particle break free. (author)
International Nuclear Information System (INIS)
Ress, R.I.
1976-01-01
Charged particles are entrained in a predetermined direction, independent of their polarity, in a circular orbit by a magnetic field rotating at high speed about an axis in a closed cylindrical or toroidal vessel. The field may be generated by a cylindrical laser structure, whose beam is polygonally reflected from the walls of an excited cavity centered on the axis, or by high-frequency energization of a set of electromagnets perpendicular to the axis. In the latter case, a separate magnetostatic axial field limits the orbital radius of the particles. These rotating and stationary magnetic fields may be generated centrally or by individual magnets peripherally spaced along its circular orbit. Chemical or nuclear reactions can be induced by collisions between the orbiting particles and an injected reactant, or by diverting high-speed particles from one doughnut into the path of counterrotating particles in an adjoining doughnut
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)
A quantum kinematics for asymptotically flat gravity
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.
Growth Kinematics of Opening-Mode Fractures
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
A kinematic view of loop closure.
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
Two-particle versus three-particle interactions in single ionization of helium by ion impact
International Nuclear Information System (INIS)
Schulz, M; Moshammer, R; Fischer, D; Ullrich, J
2004-01-01
We have performed kinematically complete experiments on single ionization of He by 100 MeV amu -1 C 6+ and 3.6 MeV amu -1 Au 24,53+ impact. By analysing doubly differential cross sections (DDCS) as a function of the momenta of all two-particle sub-systems we studied the importance of two-particle interactions. Furthermore, presenting the squared momenta of all three collision fragments simultaneously in a Dalitz plot, we evaluated the role of three-particle interactions. Finally, both for the DDCS and the Dalitz plots the corresponding correlation function was analysed. While the absolute cross sections confirm that ionization predominantly leads to a momentum exchange between the electron and the recoil-ion, the correlation function reveals strong correlations between the particles of any two-particle sub-system. Three-particle correlations, which are not accounted for by perturbative calculations, are quite significant as well, at least for certain kinematic conditions
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.
Particle acceleration at a reconnecting magnetic separator
Threlfall, J.; Neukirch, T.; Parnell, C. E.; Eradat Oskoui, S.
2015-02-01
Context. While the exact acceleration mechanism of energetic particles during solar flares is (as yet) unknown, magnetic reconnection plays a key role both in the release of stored magnetic energy of the solar corona and the magnetic restructuring during a flare. Recent work has shown that special field lines, called separators, are common sites of reconnection in 3D numerical experiments. To date, 3D separator reconnection sites have received little attention as particle accelerators. Aims: We investigate the effectiveness of separator reconnection as a particle acceleration mechanism for electrons and protons. Methods: We study the particle acceleration using a relativistic guiding-centre particle code in a time-dependent kinematic model of magnetic reconnection at a separator. Results: The effect upon particle behaviour of initial position, pitch angle, and initial kinetic energy are examined in detail, both for specific (single) particle examples and for large distributions of initial conditions. The separator reconnection model contains several free parameters, and we study the effect of changing these parameters upon particle acceleration, in particular in view of the final particle energy ranges that agree with observed energy spectra.
Coulomb interactions in particle beams
International Nuclear Information System (INIS)
Jansen, G.H.
1988-01-01
This thesis presents a theoretical description of the Coulomb interaction between identical charged particles (electrons or ions) in focussed beam. The charge-density effects as well as the various statistical interaction effects, known as the Boersch effect and the 'trajectory displacement effect', are treated. An introductory literature survey is presented from which the large differences in theoretical approach appear. Subsequently the methods are investigated which are used in studies of comparable problems in plasma physics and stellar dynamics. These turn out to be applicable to particle beams only for certain extreme conditions. The approach finally chosen in this study is twofold. On the one hand use is made of a semi-analytical model in which the statistical and dynamical aspects of the N-particle problem are reduced to two-particle problem. This model results in a number of explicit equations in the experimental parameters, with ties of the beam can be determined directly. On the other hand use has been made of a purely numerical Monte Carlo model in which the kinematical equations of an ensemble interacting particles with 'at random' chosen starting conditions are solved exactly. This model does not lead to general expressions, but yields a specific numerical prediction for each simulated experimental situation. The results of both models appear to agree well mutually. This yields a consistent theory which complements the existing knowledge of particle optics and which allow the description of systems in which the interaction between particles can not be neglected. The predictions of this theory are qualitatively and quantitatively compared with those from some other models, recently reported in literature. (author). 256 refs.; 114 figs.; 1180 schemes; 5 tabs
Estimation of kinematic parameters in CALIFA galaxies: no-assumption on internal dynamics
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
Kinematic Analysis of a Posterior-stabilized Knee Prosthesis
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
Kinematic cross-correlation induces sensory integration across separate objects.
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.
Kinematic analysis of a posterior-stabilized knee prosthesis.
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.
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.
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
Flexible margin kinematics and vortex formation of Aurelia aurita and Robojelly.
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.
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.
The APOSTLE project: Local Group kinematic mass constraints and simulation candidate selection
Fattahi, Azadeh; Navarro, Julio F.; Sawala, Till; Frenk, Carlos S.; Oman, Kyle A.; Crain, Robert A.; Furlong, Michelle; Schaller, Matthieu; Schaye, Joop; Theuns, Tom; Jenkins, Adrian
2016-03-01
We use a large sample of isolated dark matter halo pairs drawn from cosmological N-body simulations to identify candidate systems whose kinematics match that of the Local Group (LG) of galaxies. We find, in agreement with the `timing argument' and earlier work, that the separation and approach velocity of the Milky Way (MW) and Andromeda (M31) galaxies favour a total mass for the pair of ˜5 × 1012 M⊙. A mass this large, however, is difficult to reconcile with the small relative tangential velocity of the pair, as well as with the small deceleration from the Hubble flow observed for the most distant LG members. Halo pairs that match these three criteria have average masses a factor of ˜2 times smaller than suggested by the timing argument, but with large dispersion. Guided by these results, we have selected 12 halo pairs with total mass in the range 1.6-3.6 × 1012 M⊙ for the APOSTLE project (A Project Of Simulating The Local Environment), a suite of hydrodynamical resimulations at various numerical resolution levels (reaching up to ˜104 M⊙ per gas particle) that use the subgrid physics developed for the EAGLE project. These simulations reproduce, by construction, the main kinematics of the MW-M31 pair, and produce satellite populations whose overall number, luminosities, and kinematics are in good agreement with observations of the MW and M31 companions. The APOSTLE candidate systems thus provide an excellent testbed to confront directly many of the predictions of the Λ cold dark matter cosmology with observations of our local Universe.
Kinematic synthesis of adjustable robotic mechanisms
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
International Nuclear Information System (INIS)
Kenyon, I.R.
1987-01-01
Intended for undergraduate and postgraduate students the book concentrates on the 'standard model' and the gauge symmetries. Leptons, quarks and forces are introduced at the beginning, followed by experimental techniques which have found them. Gauge theories are dealt with in order of increasing complexity - quantum electrodynamics and the gauge principle, symmetries and conservation laws, colour and quantum chromodynamics, the V - A theory of weak interactions and electroweak unification. Attention is then focussed on the hadrons. Deep inelastic scattering of hadrons is explained first, then hadron spectroscopy and then hadron interactions. Current developments beyond the Standard model - grand unification, supersymmetry, cosmology and gravitation -are discussed in the final chapter. The appendices cover kinematic, cross-section and decay-rate formulae, Breit-Wigner resonances, some Clebsch-Gordan coefficient tables, a table of particle properties, exercises and answers, and the Dirac equation. There is also an appendix on calculating scattering amplitudes for fermion + fermion going to fermion + fermion. A list of references is given. (U.K.)
Hilke, Hans Jürgen
1992-01-01
We shall discuss the principles of the main techniques applied to particle detection (including front-end electronics), the construction and performance of some of the devices presently in operation and a few ideas on future developments.
International Nuclear Information System (INIS)
Evans, D.S.
1987-01-01
The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries
Elementary particles and particle interactions
International Nuclear Information System (INIS)
Bethge, K.; Schroeder, U.E.
1986-01-01
This book is a textbook for an introductory course of elementary particle physics. After a general introduction the symmetry principles governing the interactions of elementary particles are discussed. Then the phenomenology of the electroweak and strong interactions are described together with a short introduction to the Weinberg-Salam theory respectively to quantum chromodynamics. Finally a short outlook is given to grand unification with special regards to SU(5) and cosmology in the framework of the current understanding of the fundamental principles of nature. In the appendix is a table of particle properties and physical constants. (HSI) [de
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)
General analytical shakedown solution for structures with kinematic hardening materials
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.
Transverse masses and kinematic constraints: from the boundary to the crease
International Nuclear Information System (INIS)
Barr, Alan J.; Gripaios, Ben; Lester, Christopher G.
2009-01-01
We re-examine the kinematic variable m T2 and its relatives in the light of recent work by Cheng and Han. Their proof that m T2 admits an equivalent, but implicit, definition as the 'boundary of the region of parent and daughter masses that is kinematically consistent with the event hypothesis' is far-reaching in its consequences. We generalize their result both to simpler cases (m T , the transverse mass) and to more complex cases (m TGen ). We further note that it is possible to re-cast many existing and unpleasant proofs (e.g. those relating to the existence or properties of 'kink' and 'crease' structures in m T2 ) into almost trivial forms by using the alternative definition. Not only does this allow us to gain better understanding of those existing results, but it also allows us to write down new (and more or less explicit) definitions of (a) the variable that naturally generalizes m T2 to the case in which the parent or daughter particles are not identical, and (b) the inverses of m T and m T2 - which may be useful if daughter masses are known and bounds on parent masses are required. We note the implications that these results may have for future matrix-element likelihood techniques.
Amount of kinematic feedback affects learning of speech motor skills.
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.
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.
Pure Gravities via Color-Kinematics Duality for Fundamental Matter
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.
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)
Kinematic analysis of parallel manipulators by algebraic screw theory
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...
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.
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.
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.
High-energy particle diffraction
International Nuclear Information System (INIS)
Barone, V.; Predazzi, E.
2002-01-01
This monograph gives a comprehensive and up-to-date overview of soft and hard diffraction processes in strong interaction physics. The first part covers the general formalism (the optical analogy, the eikonal picture, high-energy kinematics, S-matrix theory) and soft hadron-hadron scattering (including the Regge theory) in a complete and mature presentation. It can be used as a textbook in particle physics classes. The remainder of the book is devoted to the 'new diffraction': the pomeron in QCD, low-x physics, diffractive deep inelastic scattering and related processes, jet production etc. It presents recent results and experimental findings and their phenomenological interpretations. This part addresses graduate students as well as researchers. (orig.)
Vortex re-capturing and kinematics in human underwater undulatory swimming.
Hochstein, Stefan; Blickhan, Reinhard
2011-10-01
To maximize swimming speed athletes copy fish undulatory swimming during the underwater period after start and turn. The anatomical limitations may lead to deviations and may enforce compensating strategies. This has been investigated by analyzing the kinematics of two national female swimmers while swimming in a still water pool. Additionally, the flow around and behind the swimmers was measured with the aid of time-resolved particle image velocimetry (TR-2D-PIV). As compared to fish, the swimmers used undulatory waves characterized by much higher Strouhal numbers but very similar amplitude distributions along the body and Froude efficiencies. Vortices generated in the region of strongly flexing joints are suitable to be used pedally to enhance propulsion (vortex re-capturing). Complementing studies using numerical and technical modeling will help us to probe the efficiency of observed mechanisms and further improvements of the human strategy. Copyright © 2010 Elsevier B.V. All rights reserved.
Hilke, Hans Jürgen; Joram, Christian; CERN. Geneva
1991-01-01
Lecture 5: Detector characteristics: ALEPH Experiment cut through the devices and events - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operartion and a few ideas on the future performance. Lecture 4-pt. b Following the Scintillators. Lecture 4-pt. a : Scintillators - Used for: -Timing (TOF, Trigger) - Energy Measurement (Calorimeters) - Tracking (Fibres) Basic scintillation processes- Inorganic Scintillators - Organic Scintil - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operation and a fiew ideas on future developpement session 3 - part. b Following Calorimeters lecture 3-pt. a Calorimeters - determine energy E by total absorption of charged or neutral particles - fraction of E is transformed into measurable quantities - try to acheive sig...
International Nuclear Information System (INIS)
Samios, N.P.
1993-01-01
I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc
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.
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...
Kinematic Analysis and Performance Evaluation of Novel PRS Parallel Mechanism
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.
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.
A Kinematic, Kevlar(registered) Suspension System for an ADR
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.
Selected exercises in particle and nuclear physics
Bianchini, Lorenzo
2018-01-01
This book presents more than 300 exercises, with guided solutions, on topics that span both the experimental and the theoretical aspects of particle physics. The exercises are organized by subject, covering kinematics, interactions of particles with matter, particle detectors, hadrons and resonances, electroweak interactions and flavor physics, statistics and data analysis, and accelerators and beam dynamics. Some 200 of the exercises, including 50 in multiple-choice format, derive from exams set by the Italian National Institute for Nuclear Research (INFN) over the past decade to select its scientific staff of experimental researchers. The remainder comprise problems taken from the undergraduate classes at ETH Zurich or inspired by classic textbooks. Whenever appropriate, in-depth information is provided on the source of the problem, and readers will also benefit from the inclusion of bibliographic details and short dissertations on particular topics. This book is an ideal complement to textbooks on experime...
Martin, Brian R
2017-01-01
An accessible and carefully structured introduction to Particle Physics, including important coverage of the Higgs Boson and recent progress in neutrino physics. Fourth edition of this successful title in the Manchester Physics series. Includes information on recent key discoveries including : An account of the discovery of exotic hadrons, beyond the simple quark model; Expanded treatments of neutrino physics and CP violation in B-decays; An updated account of ‘physics beyond the standard model’, including the interaction of particle physics with cosmology; Additional problems in all chapters, with solutions to selected problems available on the book’s website; Advanced material appears in optional starred sections.
Reiter, P; Blazhev, A A; Nardelli, S; Stora, T; Tengborn, E A; Kruecken, R; Voulot, D; Korten, W; Srebrny, J; Clement, E; Lo bianco, G; Sorlin, O H; Habs, D; Fraile prieto, L M; Chapman, R; Nilsson, T; Diriken, J V J; Jenkins, D G; Wady, P T; Kroell, T; Patronis, N; Angus, L J; Iwanicki, J S
We plan to study states in $^{46}$ Ar via the (t,p) two-neutron transfer reaction in inverse kinematics in order to identify and characterize excited states and to gain insights into the onset of deformation and the possible occurrence of shape-coexistence in this region where the N = 28 shell closure may be weakening. The experiment will be performed using accelerated beams from REX-ISOLDE and the T-REX particle detector set-up inside MINIBALL. We request a total of 30 shifts + 3 shifts for beam commissioning.
Scattering in relativistic particle mechanics
International Nuclear Information System (INIS)
De Bievre, S.
1986-01-01
The problem of direct interaction in relativistic particle mechanics has been extensively studied and a variety of models has been proposed avoiding the conclusions of the so-called no-interaction theorems. In this thesis the authors studied scattering in the relativistic two-body problem. He uses the results to analyze gauge invariance in Hamiltonian constraint models and the uniqueness of the symplectic structure in manifestly covariant relativistic particle mechanics. A general geometric framework that underlies approaches to relativistic particle mechanics is presented and the kinematic properties of the scattering transformation, i.e., those properties that arise solely from the invariance of the theory under the Poincare group are studied. The second part of the analysis of the relativistic two-body scattering problem is devoted to the dynamical properties of the scattering process. Using general geometric arguments, gauge invariance of the scattering transformation in the Todorov-Komar Hamiltonian constraint model is proved. Finally, quantization of the models is discussed
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.
Kinematics and design of a class of parallel manipulators
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
Synchronization and collective motion of globally coupled Brownian particles
International Nuclear Information System (INIS)
Sevilla, Francisco J; Heiblum-Robles, Alexandro; Dossetti, Victor
2014-01-01
In this work, we study a system of passive Brownian (non-self-propelled) particles in two dimensions, interacting only through a social-like force (velocity alignment in this case) that resembles Kuramoto's coupling among phase oscillators. We show that the kinematical stationary states of the system go from a phase in thermal equilibrium with no net flux of particles, to far-from-equilibrium phases exhibiting collective motion by increasing the coupling among particles. The mechanism that leads to the instability of the equilibrium phase relies on the competition between two time scales, namely, the mean collision time of the Brownian particles in a thermal bath and the time it takes for a particle to orient its direction of motion along the direction of motion of the group. Our results show a clear connection between collective motion and the Kuramoto model for synchronization, in our case, for the direction of motion of the particles. (paper)
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).
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.
Czech Academy of Sciences Publication Activity Database
Aad, G.; Abbott, B.; Abdallah, J.; Chudoba, Jiří; Havránek, Miroslav; Hejbal, Jiří; Jakoubek, Tomáš; Kepka, Oldřich; Kupčo, Alexander; Kůs, Vlastimil; Lokajíček, Miloš; Lysak, R.; Marčišovský, Michal; Mikeštíková, Marcela; Němeček, Stanislav; Šícho, Petr; Staroba, Pavel; Svatoš, Michal; Taševský, Marek; Vrba, Václav
2015-01-01
Roč. 91, č. 11 (2015), "112013-1"-"112013-25" ISSN 1550-7998 R&D Projects: GA MŠk(CZ) LG13009 Institutional support: RVO:68378271 Keywords : ATLAS * CERN LHC Coll * acceptance * kinematics * CERN Lab * experimental results * p p --> 2top anything * 8000 GeV-cms Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.643, year: 2014
International Nuclear Information System (INIS)
Prasad, R.
1984-01-01
Two previous monographs report on investigations into the extent to which a unified field theory can satisfactorily describe physical reality. The first, Unified field Theory, showed that the paths within a non-Riemannian space are governed by eigenvalue equations. The second, Fundamental Constants, show that the field tensors satisfy sets of differential equations with solutions which represent the evolution of the fields along the paths of the space. The results from the first two monographs are used in this one to make progress on the theory of elementary particles. The five chapters are as follows - Quantum mechanics, gravitation and electromagnetism are aspects of the Unified theory; the fields inside the particle; the quadratic and linear theories; the calculation of the eigenvalues and elementary particles as stable configurations of interacting fields. It is shown that it is possible to construct an internal structure theory for elementary particles. The theory lies within the framework of Einstein's programme-to identify physical reality with a specified geometrical structure. (U.K.)
International Nuclear Information System (INIS)
Miller, David J.
1987-01-01
The Conference on Position-Sensitive Detectors held at London's University College from 7-11 September highlighted the importance and the growing applications of these precision devices in many branches of science, underlining once again the high spinoff potential for techniques developed inside particle physics
International Nuclear Information System (INIS)
Mais, H.; Ripken, G.; Wrulich, A.; Schmidt, F.
1986-02-01
After a brief description of typical applications of particle tracking in storage rings and after a short discussion of some limitations and problems related with tracking we summarize some concepts and methods developed in the qualitative theory of dynamical systems. We show how these concepts can be applied to the proton ring HERA. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Miller, David J.
1987-10-15
The Conference on Position-Sensitive Detectors held at London's University College from 7-11 September highlighted the importance and the growing applications of these precision devices in many branches of science, underlining once again the high spinoff potential for techniques developed inside particle physics.
2005-01-01
While biomedicine and geoscience use grids to bring together many different sub-disciplines, particle physicists use grid computing to increase computing power and storage resources, and to access and analyze vast amounts of data collected from detectors at the world's most powerful accelerators (1 page)
Charged-particle distributions in pp interactions at √s= 8 TeV measured with the ATLAS detector
Czech Academy of Sciences Publication Activity Database
Aad, G.; Abbott, B.; Abdallah, J.; Chudoba, Jiří; Havránek, Miroslav; Hejbal, Jiří; Jakoubek, Tomáš; Kepka, Oldřich; Kupčo, Alexander; Kůs, Vlastimil; Lokajíček, Miloš; Lysák, Roman; Marčišovský, Michal; Mikeštíková, Marcela; Němeček, Stanislav; Penc, Ondřej; Šícho, Petr; Staroba, Pavel; Svatoš, Michal; Taševský, Marek; Vrba, Václav
2016-01-01
Roč. 76, č. 7 (2016), s. 1-46, č. článku 403. ISSN 1434-6044 Institutional support: RVO:68378271 Keywords : ATLAS * CERN LHC Coll * experimental results * 8000 GeV-cms * kinematics * charged particle * rapidity * trigger Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.331, year: 2016
MCAPM: All particle method generator and collision package
International Nuclear Information System (INIS)
Rathkopf, J.A.
1992-11-01
MCAPM (Monte Carlo All Particle Method) is a collection of subroutines that read the data necessary for and perform the physics involved in collisions of neutrons, protons, deuterons, helium-3, alphas, and gammas with background material. These subroutines are divided into two packages. The first package, gen2000, reads the cross sections and distributions from binary libraries that describe in-flight reactions and formats them in a form appropriate for use by the second package. Libraries are organized by incident particle type, but contain information describing the attributes of all output particles. The method of tabulating cross section data depends on the incident particle type. Neutron and charged particle cross sections are multi-group; gamma cross sections are log-log interpolated from an energy grid consistent over all target elements. The second package, bang2000, uses these data to perform the collision physics. Each Monte Carlo particle possesses a discrete energy value allowing the kinematics of collisions to be performed on a continuous energy basis. The result of the kinematics is the attributes (type, number, energy, and direction) of all the particles emerging from the collision. MCAPM is modular and has been ported to a variety of platforms
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, ...
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 ...
Adding Image Constraints to Inverse Kinematics for Human Motion Capture
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.
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...
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 ...
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)
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)
Soft tissue artifact in canine kinematic gait analysis
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,
Modern techniques in galaxy kinematics : Results from planetary nebula spectroscopy
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
Kinematic Measures of Imitation Fidelity in Primary School Children
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…
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.
Is Active Tectonics on Madagascar Consistent with Somalian Plate Kinematics?
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.
Kinematics analysis of a robotic zipper prototype for miniaturisation
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),
Differences in Soccer Kick Kinematics between Blind Players and Controls
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…
Kinematic signature of a rotating bar near a resonance
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.
Can co-activation reduce kinematic variability? A simulation study.
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
Using Robotics in Kinematics Classes: Exploring Braking and Stopping Distances
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…
A digital database of wrist bone anatomy and carpal kinematics.
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.
Circular braiding take-up speed generation using inverse kinematics
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
Primate Anatomy, Kinematics, and Principles for Humanoid Design
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.
Hallux valgus surgery affects kinematic parameters during gait.
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 Â© 2016 Elsevier Ltd. All rights reserved.
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...
International Nuclear Information System (INIS)
Rosa, Bogdan; Parishani, Hossein; Ayala, Orlando; Wang, Lian-Ping; Grabowski, Wojciech W
2011-01-01
In recent years, direct numerical simulation (DNS) approach has become a reliable tool for studying turbulent collision-coalescence of cloud droplets relevant to warm rain development. It has been shown that small-scale turbulent motion can enhance the collision rate of droplets by either enhancing the relative velocity and collision efficiency or by inertia-induced droplet clustering. A hybrid DNS approach incorporating DNS of air turbulence, disturbance flows due to droplets, and droplet equation of motion has been developed to quantify these effects of air turbulence. Due to the computational complexity of the approach, a major challenge is to increase the range of scales or size of the computation domain so that all scales affecting droplet pair statistics are simulated. Here we discuss our on-going work in this direction by improving the parallel scalability of the code, and by studying the effect of large-scale forcing on pair statistics relevant to turbulent collision. New results at higher grid resolutions show a saturation of pair and collision statistics with increasing flow Reynolds number, for given Kolmogorov scales and small droplet sizes. Furthermore, we examine the orientation dependence of pair statistics which reflects an interesting coupling of gravity and droplet clustering.
Software Development for the Kinematic Analysis of a Lynx 6 Robot Arm
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...
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.
The gait standard deviation, a single measure of kinematic variability.
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.
Fatigue effects on bar kinematics during the bench press.
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.
Surgical gesture classification from video and kinematic data.
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.
Degond, Pierre; Tadmor, Eitan
2017-01-01
This volume collects ten surveys on the modeling, simulation, and applications of active particles using methods ranging from mathematical kinetic theory to nonequilibrium statistical mechanics. The contributing authors are leading experts working in this challenging field, and each of their chapters provides a review of the most recent results in their areas and looks ahead to future research directions. The approaches to studying active matter are presented here from many different perspectives, such as individual-based models, evolutionary games, Brownian motion, and continuum theories, as well as various combinations of these. Applications covered include biological network formation and network theory; opinion formation and social systems; control theory of sparse systems; theory and applications of mean field games; population learning; dynamics of flocking systems; vehicular traffic flow; and stochastic particles and mean field approximation. Mathematicians and other members of the scientific commu...
International Nuclear Information System (INIS)
Merwin, S.E.; Moeller, M.P.
1989-01-01
Nuclear Regulatory Commission (NRC) licensees are required to assess the dose to skin from a hot particle contamination event at a depth of skin of7mg/cm 2 over an area of 1 cm 2 and compare the value to the current dose limit for the skin. Although the resulting number is interesting from a comparative standpoint and can be used to predict local skin reactions, comparison of the number to existing limits based on uniform exposures is inappropriate. Most incidents that can be classified as overexposures based on this interpretation of dose actually have no effect on the health of the worker. As a result, resources are expended to reduce the likelihood that an overexposure event will occur when they could be directed toward eliminating the cause of the problem or enhancing existing programs such as contamination control. Furthermore, from a risk standpoint, this practice is not ALARA because some workers receive whole body doses in order to minimize the occurrence of hot particle skin contaminations. In this paper the authors suggest an alternative approach to controlling hot particle exposures
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
Guala, M.; Liu, M.
2017-12-01
The kinematics of sediment particles is investigated by non-intrusive imaging methods to provide a statistical description of bedload transport in conditions near the threshold of motion. In particular, we focus on the cyclic transition between motion and rest regimes to quantify the waiting time statistics inferred to be responsible for anomalous diffusion, and so far elusive. Despite obvious limitations in the spatio-temporal domain of the observations, we are able to identify the probability distributions of the particle step time and length, velocity, acceleration, waiting time, and thus distinguish which quantities exhibit well converged mean values, based on the thickness of their respective tails. The experimental results shown here for four different transport conditions highlight the importance of the waiting time distribution and represent a benchmark dataset for the stochastic modeling of bedload transport.
Energy Technology Data Exchange (ETDEWEB)
Khare, A.
1980-07-01
Current state of art in the discovery of new elementary particles is reviewed. At present, quarks and mesons are accepted as the basic constituents of matter. The charmonium model (canti-c system), and the 'open charm' are discussed. Explanations are offered for the recent discovery of the heavy lepton tau. Quark states such as the beauty and taste are also dealt with at length. The properties of the tanti-t bound system are speculated. It is concluded that the understanding of canti-c and banti-b families is facilitated by the assumption of the quarkonium model. Implications at the astrophysical level are indicated.
Collinson, Chris
1995-01-01
* Assumes no prior knowledge* Adopts a modelling approach* Numerous tutorial problems, worked examples and exercises included* Elementary topics augmented by planetary motion and rotating framesThis text provides an invaluable introduction to mechanicsm confining attention to the motion of a particle. It begins with a full discussion of the foundations of the subject within the context of mathematical modelling before covering more advanced topics including the theory of planetary orbits and the use of rotating frames of reference. Truly introductory , the style adoped is perfect for those u
Macroscopic kinematics of the Hall electric field under influence of carrier magnetic moments
International Nuclear Information System (INIS)
Sakai, Masamichi
2016-01-01
The relativistic effect on electromagnetic forces yields two types of forces which depend on the velocity of the relevant particles: (i) the usual Lorentz force exerted on a moving charged particle and (ii) the apparent Lorentz force exerted on a moving magnetic moment. In sharp contrast with type (i), the type (ii) force originates due to the transverse field induced by the Hall effect (HE). This study incorporates both forces into a Drude-type equation with a fully spin-polarized condition to investigate the effects of self-consistency of the source and the resultant fields on the HE. We also examine the self-consistency of the carrier kinematics and electromagnetic dynamics by simultaneously considering the Drude type equation and Maxwell equations at low frequencies. Thus, our approach can predict both the dc and ac characteristics of the HE, demonstrating that the dc current condition solely yields the ordinary HE, while the ac current condition yields generation of both fundamental and second harmonic modes of the HE field. When the magnetostatic field is absent, the simultaneous presence of dc and ac longitudinal currents generates the ac HE that has both fundamental frequency and second harmonic.
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.
[Advances on biomechanics and kinematics of sprain of ankle joint].
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.
A School Experiment in Kinematics: Shooting from a Ballistic Cart
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.
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
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)
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
D2 Delta Robot Structural Design and Kinematics Analysis
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.
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
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
Kinematical Compatibility Conditions for Vorticity Across Shock Waves
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.
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...
The kinematic footprints of five stellar streams in Andromeda's halo
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
VRACK: measuring pedal kinematics during stationary bike cycling.
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.
Stroller running: Energetic and kinematic changes across pushing methods.
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.
Linghu, Zelin; Wu, Jianing; Wang, Changlong; Yan, Shaoze
2015-11-01
The mouthpart of a honeybee is prone to contamination by granular particles such as pollen or dirt from the field. To clean the contaminated mouthparts, a honeybee swings its foreleg tarsi forward and backward to brush the proboscis continuously, sweeping the contaminant from the surfaces of the labial palpi, galeae, and bushy haired tongue (glossa). This grooming behavior has been documented but the dynamic characteristics therein have not been investigated yet. We quantified the grooming behavior of a honeybee from the perspective of kinematic and tribological properties. We captured high-speed videos that recorded the mouthpart grooming patterns of honeybees from the front and side views and measured the friction on the grooming surfaces using a precision dynamometer. During grooming, a honeybee first positions the mouthpart and then places a pair of foreleg tarsi to the tubular-folded galea. The tarsi press the galea and labial palpi and slide downward while keeping close contact with the galea. Then, the hairy glossa stretches out of the temporary tube with the glossa setae erected. The tarsi slowly slide down when grooming the glossa. In the return stroke of grooming, the foreleg tarsi detach from the mouthpart and retreat swiftly. Friction analysis shows that the honeybees can coordinate the velocity of the foreleg tarsi to the sectionalized tribological property of the tarsus-mouthpart interface. The specific grooming pattern enables honeybees to save energy and resist wear, resulting in a possible highly evolved grooming strategy. These findings lead to further understanding of the honeybee's grooming behavior facilitated by the special motion kinematics and friction characteristics. Copyright © 2015 Elsevier Ltd. All rights reserved.
Manipulation of the kinematic chain using visual biofeedback
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...
Ionised gas kinematics in bipolar H II regions
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.
An investigation into the kinematics of 2 cervical manipulation techniques.
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.
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.
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.
Effects of marathon fatigue on running kinematics and economy
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...
From movement kinematics to social cognition: the case of autism
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
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)
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
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
Kinematic and ground reaction force accommodation during weighted walking.
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
Kinematics changes in technique of a softball pitch
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...
Kinematic and Kinetic Evaluation of High Speed Backward Running
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
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
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)
Dancers with achilles tendinopathy demonstrate altered lower extremity takeoff kinematics.
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.
Kinematic variables of table vault on artistic gymnastics
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...
Altered Perceptual Sensitivity to Kinematic Invariants in Parkinson's Disease
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...
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
The Emotional Modulation of Facial Mimicry: A Kinematic Study
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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
The Emotional Modulation of Facial Mimicry: A Kinematic Study.
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
Scapular kinematics and muscle activities during pushing tasks.
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.
Coulomb effects in particle distributions inclusive
International Nuclear Information System (INIS)
Erazmus, B.; Martin, L.; Pluta, J.; Stavinky, A.
1997-01-01
Single pion distributions from central 158 A.GeV/c Pb + Pb collisions measured by the NA44 experiment show the effect of Coulomb interaction with the net charge produced during the reaction. Coulomb effects are analyzed with the help of the microscopic model RQMD and a model including the Coulomb interaction. Different sets of kinematical characteristics of the net charge have been used to reproduce the experimental data and a strong sensitivity to the charge value has been found. This study has evidenced the non-negligible influence of a Coulomb charge, present in the region of the central rapidity in heavy ion collisions on the inclusive distributions of the produced particles. A more thorough analysis of the data obtained from the experiment NA44 is now under way to take into account the hyperon decay that can modify the fraction of different particles, particularly at low transverse momenta
Evidence for halo kinematics among cool carbon-rich dwarfs
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.
Inverse Kinematics for Industrial Robots using Conformal Geometric Algebra
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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.
Analysis of a closed-kinematic chain robot manipulator
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.
Nozzle Mounting Method Optimization Based on Robot Kinematic Analysis
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.
Foot and Ankle Kinematics During Descent From Varying Step Heights.
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.
A nonlinear dynamics of trunk kinematics during manual lifting tasks.
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.
Kinematics of Mass Transport Deposits revealed by magnetic fabrics
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.
Integrating concepts and skills: Slope and kinematics graphs
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.
MALT90 Kinematic Distances to Dense Molecular Clumps
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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.
KINEMATIC AND KINETIC VARIABLES DIFFER BETWEEN KETTLEBELL SWING STYLES.
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.
Comparison of trunk kinematics in trunk training exercises and throwing.
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.
Kinematic decomposition and classification of octopus arm movements.
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.
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.
Kinematic classification of iliotibial band syndrome in runners.
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.
Effects of contracture on gait kinematics: A systematic review.
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.
Improved kinect-based spatiotemporal and kinematic treadmill gait assessment.
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 Â© 2016 Elsevier B.V. All rights reserved.
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.
Kinematic characteristics of tenodesis grasp in C6 quadriplegia.
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.
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.
RadSim: a program to simulate individual particle interactions for educational purposes
International Nuclear Information System (INIS)
Verhaegen, Frank; Palefsky, Steven; DeBlois, Francois
2006-01-01
A program was developed, RadSim, which can be used to simulate certain individual interactions of photons, electrons, positrons and alpha particles with a single atom for educational purposes. The program can be run in two modes: manual and simulated. In the manual mode, an individual particle undergoing a specified interaction with a target atom can be simulated, which essentially comes down to a graphical evaluation of kinematic equations. In the simulated mode, a preset number of identical particles are allowed to undergo a specified interaction type with a target atom. The exit channel of the interaction is sampled from probability distributions using Monte Carlo methods. The incoming and outgoing particles are visualized and the frequency distribution of the kinematic variables of the exit channel is displayed graphically. It has to be emphasized that RadSim was mainly developed for educational purposes. (note)
Fermilab | Particle Physics Division
Diversity Education Safety Sustainability and Environment Contact Science Science Particle Physics Neutrinos Scientific Computing Research & Development Key Discoveries Benefits of Particle Physics Particle Superconducting Test Accelerator LHC and Future Accelerators Accelerators for Science and Society Particle Physics
Energy Technology Data Exchange (ETDEWEB)
Sauerland, Philip
2011-04-15
The Standard Model of Particle Physics (SM) postulates the universal coupling of the three lepton families to the weak current. The most precise measurement of lepton universality in W decays comes from the four experiments at the Large Electron-Positron Collider (LEP). If one compares the couplings of muons and tau leptons to the charged weak current, there is a discrepancy of nearly three standard deviations w.r.t. the SM expectation. There are models beyond the SM, which could explain the violation of lepton universality with new physics processes, if it is more than a statistical fluctuation. The Large Hadron Collider (LHC) offers a great opportunity to study decays of the charged-weak gauge bosons at very high event rates and at unmatched collision energies. This thesis presents an analysis strategy to test lepton universality with the Compact Muon Solenoid experiment (CMS) at the LHC. The analysis focusses on the decays of the W{sup {+-}} boson to particles of the second and third lepton family. For this purpose detector-simulated proton-proton events are used. The identification and reconstruction of tau leptons is a difficult task at the LHC. The reconstruction is often restricted by the limited precision of the commonly used collinear approximation. The application of a kinematic fit to particular tau-decay modes can improve the experimental resolution and provides an efficient background suppression. The development of such a fit with kinematic constraints derived from the topology of the decay {tau} {yields} 3{pi}{sup {+-}} + {nu}{sub {tau}} is described. The kinematic fit of tau leptons is not limited to the test for lepton universality, but can be deployed by various physics analyses in a broad energy range of the tau leptons. The event topology of W{sup {+-}} decays with leptonic final states is studied. Two event selections are developed: one for the W{sup {+-}} {yields} {tau}{nu} and one for the W{sup {+-}} {yields} {mu}{nu} decay. A common online
International Nuclear Information System (INIS)
Sauerland, Philip
2011-01-01
The Standard Model of Particle Physics (SM) postulates the universal coupling of the three lepton families to the weak current. The most precise measurement of lepton universality in W decays comes from the four experiments at the Large Electron-Positron Collider (LEP). If one compares the couplings of muons and tau leptons to the charged weak current, there is a discrepancy of nearly three standard deviations w.r.t. the SM expectation. There are models beyond the SM, which could explain the violation of lepton universality with new physics processes, if it is more than a statistical fluctuation. The Large Hadron Collider (LHC) offers a great opportunity to study decays of the charged-weak gauge bosons at very high event rates and at unmatched collision energies. This thesis presents an analysis strategy to test lepton universality with the Compact Muon Solenoid experiment (CMS) at the LHC. The analysis focusses on the decays of the W ± boson to particles of the second and third lepton family. For this purpose detector-simulated proton-proton events are used. The identification and reconstruction of tau leptons is a difficult task at the LHC. The reconstruction is often restricted by the limited precision of the commonly used collinear approximation. The application of a kinematic fit to particular tau-decay modes can improve the experimental resolution and provides an efficient background suppression. The development of such a fit with kinematic constraints derived from the topology of the decay τ → 3π ± + ν τ is described. The kinematic fit of tau leptons is not limited to the test for lepton universality, but can be deployed by various physics analyses in a broad energy range of the tau leptons. The event topology of W ± decays with leptonic final states is studied. Two event selections are developed: one for the W ± → τν and one for the W ± → μν decay. A common online selection is proposed, which is independent of the leptonic final state of
Particle interpretations of the PVLAS data
Energy Technology Data Exchange (ETDEWEB)
Ringwald, A.
2007-04-15
Recently the PVLAS collaboration reported the observation of a rotation of linearly polarized laser light induced by a transverse magnetic field - a signal being unexpected within standard QED. In this review, we emphasize two mechanisms which have been proposed to explain this result: production of a single light neutral spin-zero particle or pair production of light minicharged particles. We discuss a class of models, involving, in addition to our familiar ''visible'' photon, further light ''hidden paraphotons'', which mix kinematically with the visible one, and further light paracharged particles. In these models, very strong astrophysical and cosmological bounds on the weakly interacting light particles mentioned above can be evaded. In the upcoming year, a number of decisive laboratory based tests of the particle interpretation of the PVLAS anomaly will be done. More generally, such experiments, exploiting high fluxes of low-energy photons and/or large electromagnetic fields, will dig into previously unconstrained parameter space of the above mentioned models. (orig.)
Climbing fibers predict movement kinematics and performance errors.
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
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
Differences between kinematic synergies and muscle synergies during two-digit grasping
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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
Czech Academy of Sciences Publication Activity Database
Aad, G.; Abbott, B.; Abdallah, J.; Chudoba, Jiří; Havránek, Miroslav; Hejbal, Jiří; Jakoubek, Tomáš; Kepka, Oldřich; Kupčo, Alexander; Kůs, Vlastimil; Lokajíček, Miloš; Lysák, Roman; Marčišovský, Michal; Mikeštíková, Marcela; Němeček, Stanislav; Šícho, Petr; Staroba, Pavel; Svatoš, Michal; Taševský, Marek; Vrba, Václav
2015-01-01
Roč. 75, č. 10 (2015), s. 466 ISSN 1434-6044 R&D Projects: GA MŠk(CZ) LG13009 Institutional support: RVO:68378271 Keywords : ATLAS * transverse momentum dependence * CERN LHC Coll * correlation function * two-particle * saturation * kinematics * CERN Lab Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.912, year: 2015
Antonella Del Rosso
2014-01-01
These devices are designed to provide a current pulse of 5000 Amps which will in turn generate a fast magnetic pulse that steers the incoming beam into the LHC. Today, the comprehensive upgrade of the LHC injection kicker system is entering its final stages. The upgraded system will ensure the LHC can be refilled without needing to wait for the kicker magnets to cool, thus enhancing the performance of the whole accelerator. An upgraded kicker magnet in its vacuum tank, with an upgraded beam screen. The LHC is equipped with two kicker systems installed at the injection points (near points 2 and 8, see schematic diagram) where the particle beams coming from the SPS are injected into the accelerator’s orbit. Each system comprises four magnets and four pulse generators in which the field rises to 0.12 Tesla in less than 900 nanoseconds and for a duration of approximately 8 microseconds. Although the injection kickers only pulse 12 times to fill the LHC up with beam, the LHC beam circ...
International Nuclear Information System (INIS)
Loddenkoetter, Thomas
2012-08-01
In order to provide discrimination between the Wt-channel signal and its backgrounds for analyses that try to measure single top-quark production in the Wt-channel, a kinematic fit to the lepton+jets decay mode of the Wt-channel has been implemented using the KLFitter package. The fit has been validated by studying its performance in terms of the efficiency of the fit to correctly assign the final-state quarks of the fit model to the measured jets as a function of various parameters, as well as the improvement of the energy resolutions of the fitted particles due to the fit. By combining the output variables of the kinematic fitter using neural networks, it has been shown that the fit results are suitable to identify the decay mode of the top quark in Wt events and to identify whether the kinematic fit succeeded in correctly assigning the final-state quarks to the measured jets. In order to demonstrate the value of the kinematic fit for analysis, another neural network - again using strictly results of the kinematic fit as input - has been trained to separate to the Wt-channel signal from its backgrounds. A separation power comparable to a conventional neural-network-based Wt-channel analysis has been achieved.
Energy Technology Data Exchange (ETDEWEB)
Loddenkoetter, Thomas
2012-08-15
In order to provide discrimination between the Wt-channel signal and its backgrounds for analyses that try to measure single top-quark production in the Wt-channel, a kinematic fit to the lepton+jets decay mode of the Wt-channel has been implemented using the KLFitter package. The fit has been validated by studying its performance in terms of the efficiency of the fit to correctly assign the final-state quarks of the fit model to the measured jets as a function of various parameters, as well as the improvement of the energy resolutions of the fitted particles due to the fit. By combining the output variables of the kinematic fitter using neural networks, it has been shown that the fit results are suitable to identify the decay mode of the top quark in Wt events and to identify whether the kinematic fit succeeded in correctly assigning the final-state quarks to the measured jets. In order to demonstrate the value of the kinematic fit for analysis, another neural network - again using strictly results of the kinematic fit as input - has been trained to separate to the Wt-channel signal from its backgrounds. A separation power comparable to a conventional neural-network-based Wt-channel analysis has been achieved.
On the time delay between ultra-relativistic particles
International Nuclear Information System (INIS)
Fleury, Pierre
2016-01-01
The time delay between the receptions of ultra-relativistic particles emitted simultaneously is a useful observable for both fundamental physics and cosmology. The expression of the delay when the particles travel through an arbitrary spacetime has been derived recently by Fanizza et al., using a particular coordinate system and self-consistent assumptions. The present article shows that this formula enjoys a simple physical interpretation: the relative velocity between two ultra-relativistic particles is constant. This result reveals an interesting kinematical property of general relativity, namely that the tidal forces experienced by ultra-relativistic particles in the direction of their motion are much smaller than those experienced orthogonally to their motion.
Reconstructing particle masses in events with displaced vertices
Cottin, Giovanna
2018-03-01
We propose a simple way to extract particle masses given a displaced vertex signature in event topologies where two long-lived mother particles decay to visible particles and an invisible daughter. The mother could be either charged or neutral and the neutral daughter could correspond to a dark matter particle in different models. The method allows to extract the parent and daughter masses by using on-shell conditions and energy-momentum conservation, in addition to the displaced decay positions of the parents, which allows to solve the kinematic equations fully on an event-by-event basis. We show the validity of the method by means of simulations including detector effects. If displaced events are seen in discovery searches at the Large Hadron Collider (LHC), this technique can be applied.
On the time delay between ultra-relativistic particles
Energy Technology Data Exchange (ETDEWEB)
Fleury, Pierre, E-mail: pierre.fleury@uct.ac.za [Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, Cape Town (South Africa); Department of Physics, University of the Western Cape, Robert Sobukwe Road, Bellville 7535 (South Africa)
2016-09-10
The time delay between the receptions of ultra-relativistic particles emitted simultaneously is a useful observable for both fundamental physics and cosmology. The expression of the delay when the particles travel through an arbitrary spacetime has been derived recently by Fanizza et al., using a particular coordinate system and self-consistent assumptions. The present article shows that this formula enjoys a simple physical interpretation: the relative velocity between two ultra-relativistic particles is constant. This result reveals an interesting kinematical property of general relativity, namely that the tidal forces experienced by ultra-relativistic particles in the direction of their motion are much smaller than those experienced orthogonally to their motion.
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
Exploring the Origin of Kinematically Irregular Galaxies with MaNGA
Stark, David Vincent; Bundy, Kevin; Westfall, Kyle; Bershady, Matthew; Cheung, Edmond; Soler, Juan; Brinchmann, Jarle; Abraham, Roberto; Bizyaev, Dmitry; Masters, Karen; Weijmans, Anne-Marie; Chen, Yanmei; Jin, Yifei; Drory, Niv; Lopes, Alexandre Roman; Law, David
2018-01-01
Deviations from normal rotation in galaxies may have a number of potential drivers, including tidal interactions, gas inflows/outflows, spiral structure, bar/oval distortions, or other internally generated instabilities. Thanks to new massive IFU surveys like MaNGA, we can now characterize the gas and stellar kinematics of thousands of galaxies in the local universe, enabling statistical analyses on the frequency of disturbed kinematics, their origin, and their impact on their host galaxies. We present a census of kinematics in MaNGA using a modified version of the Radon transform to map radial variations in kinematic position angles (PA). We discuss the frequency of kinematically irregular disks, and describe commonly observed patterns in radial PA profiles. In order to constrain the drivers of these kinematic signatures, we analyze how they correlate with galaxy mass, environment, star formation history, and gas-phase metallicity.
The kinematic relationships of the upper cervical spine.
Morishita, Yuichiro; Falakassa, Jonathan; Naito, Masatoshi; Hymanson, Henry J; Taghavi, Cyrus; Wang, Jeffrey C
2009-11-15
A retrospective radiographic study. To elucidate the kinematic relationships of the upper cervical spine. To our knowledge, few reports have described the kinematic relationships of the upper cervical spine in patients with general age-related cervical spondylosis. We performed Kinetic magnetic resonance imaging for 295 consecutive patients experiencing neck pain without neurologic symptoms. Subjects with rheumatoid arthritis, traumatic history, and severe degenerative changes in the upper cervical spine were excluded. Anterior atlantodens interval (AADI) and the cervicomedullary angle in 3 different postures were measured, and the variations in each value between flexion and neutral (F-N), neutral and extension (N-E), and flexion and extension (F-E) were calculated. The subjects were classified into 3 groups according to the space available for the cord values (A: or=15 mm). AADI significantly increased from extension to flexion posture, however, no significant differences were observed in every posture among the groups. F-N variation in AADI showed no significant differences among the groups; however, N-E variation between Groups A and C and between Groups B and C and F-E variation between Groups A and C showed significant differences. The cervicomedullary angle significantly increased from flexion to extension posture, however, no significant differences were observed in every posture among the groups. Angle variations among the groups showed no significant differences, except for F-N angle variation between Groups B and C. None of the variations in AADI and the cervicomedullary angle were significantly correlated. Our results suggest that only the kinematics of the atlantoaxial movement, especially the posterior movement, was greatly affected by the narrowing of space available for the cord. The central atlantoaxial joint may be closely related to the mechanisms for protecting the spinal cord by restriction of the atlantoaxial movement.
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.
Kinematic Origins of Motor Inconsistency in Expert Pianists.
Directory of Open Access Journals (Sweden)
Kenta Tominaga
Full Text Available For top performers, including athletes and musicians, even subtle inconsistencies in rhythm and force during movement production decrease the quality of performance. However, extensive training over many years beginning in childhood is unable to perfect dexterous motor performance so that it is without any error. To gain insight into the biological mechanisms underlying the subtle defects of motor actions, the present study sought to identify the kinematic origins of inconsistency of dexterous finger movements in musical performance. Seven highly-skilled pianists who have won prizes at international piano competitions played a short sequence of tones with the right hand at a predetermined tempo. Time-varying joint angles of the fingers were recorded using a custom-made data glove, and the timing and velocity of the individual keystrokes were recorded from a digital piano. Both ridge and stepwise multiple regression analyses demonstrated an association of the inter-trial variability of the inter-keystroke interval (i.e., rhythmic inconsistency with both the rotational velocity of joints of the finger used for a keystroke (i.e., striking finger and the movement independence between the striking and non-striking fingers. This indicates a relationship between rhythmic inconsistency in musical performance and the dynamic features of movements in not only the striking finger but also the non-striking fingers. In contrast, the inter-trial variability of the key-descending velocity (i.e., loudness inconsistency was associated mostly with the kinematic features of the striking finger at the moment of the keystroke. Furthermore, there was no correlation between the rhythmic and loudness inconsistencies. The results suggest distinct kinematic origins of inconsistencies in rhythm and loudness in expert musical performance.
Kinematic Origins of Motor Inconsistency in Expert Pianists.
Tominaga, Kenta; Lee, André; Altenmüller, Eckart; Miyazaki, Fumio; Furuya, Shinichi
2016-01-01
For top performers, including athletes and musicians, even subtle inconsistencies in rhythm and force during movement production decrease the quality of performance. However, extensive training over many years beginning in childhood is unable to perfect dexterous motor performance so that it is without any error. To gain insight into the biological mechanisms underlying the subtle defects of motor actions, the present study sought to identify the kinematic origins of inconsistency of dexterous finger movements in musical performance. Seven highly-skilled pianists who have won prizes at international piano competitions played a short sequence of tones with the right hand at a predetermined tempo. Time-varying joint angles of the fingers were recorded using a custom-made data glove, and the timing and velocity of the individual keystrokes were recorded from a digital piano. Both ridge and stepwise multiple regression analyses demonstrated an association of the inter-trial variability of the inter-keystroke interval (i.e., rhythmic inconsistency) with both the rotational velocity of joints of the finger used for a keystroke (i.e., striking finger) and the movement independence between the striking and non-striking fingers. This indicates a relationship between rhythmic inconsistency in musical performance and the dynamic features of movements in not only the striking finger but also the non-striking fingers. In contrast, the inter-trial variability of the key-descending velocity (i.e., loudness inconsistency) was associated mostly with the kinematic features of the striking finger at the moment of the keystroke. Furthermore, there was no correlation between the rhythmic and loudness inconsistencies. The results suggest distinct kinematic origins of inconsistencies in rhythm and loudness in expert musical performance.
KINEMATIC CHANGES DURING A MARATHON FOR FAST AND SLOW RUNNERS
Directory of Open Access Journals (Sweden)
Maggie Chan-Roper
2012-03-01
Full Text Available The purpose of this study was to describe kinematic changes that occur during an actual marathon. We hypothesized that (1 certain running kinematic measures would change between kilometres 8 and 40 (miles 5 and 25 of a marathon and (2 fast runners would demonstrate smaller changes than slow runners. Subjects (n = 179 were selected according to finish time (Range = 2:20:47 to 5:30:10. Two high-speed cameras were used to measure sagittal-plane kinematics at kilometres 8 and 40 of the marathon. The dependent variables were stride length, contact time, peak knee flexion during support and swing, and peak hip flexion and extension during swing. Two-tailed paired t-tests were used to compare dependent variables between kilometres 8 and 40 for all subjects, and regression analyses were used to determine whether faster runners exhibited smaller changes (between miles 5 and 25 than slower runners. For all runners, every dependent variable changed significantly between kilometres 8 and 40 (p < 0.001. Stride length increased 1.3%, contact time increased 13.1%, peak knee flexion during support decreased 3.2%, and peak hip extension, knee flexion, and hip flexion during swing decreased 27.9%, increased 4.3%, and increased 7.4%, respectively (p < 0.001. Among these significant changes, all runners generally changed the same from kilometres 8 and 40 except that fast runners decreased peak knee flexion during support less than the slow runners (p < 0.002. We believe that these changes, for all runners (fast and slow, were due to fatigue. The fact that fast runners maintained knee flexion during support more consistently might be due to their condition on the race day. Strengthening of knee extensor muscles may facilitate increased knee flexion during support throughout a marathon
Expression of emotion in the kinematics of locomotion.
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
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.
Decoherence and discrete symmetries in deformed relativistic kinematics
Arzano, Michele
2018-01-01
Models of deformed Poincaré symmetries based on group valued momenta have long been studied as effective modifications of relativistic kinematics possibly capturing quantum gravity effects. In this contribution we show how they naturally lead to a generalized quantum time evolution of the type proposed to model fundamental decoherence for quantum systems in the presence of an evaporating black hole. The same structures which determine such generalized evolution also lead to a modification of the action of discrete symmetries and of the CPT operator. These features can in principle be used to put phenomenological constraints on models of deformed relativistic symmetries using precision measurements of neutral kaons.
Nonpartonic Effects in Pion Electroproduction in the Hermes Kinematical Region
International Nuclear Information System (INIS)
Uleshchenko, V.; Szczurek, A.
2002-01-01
The presentation is concerned with higher twist corrections of nonpartonic origin to semi-inclusive observables in the kinematical region relevant for the HERMES experiment. We demonstrate a strong impact of the VDM-like interaction and the exclusive production of ρ 0 meson on the extraction of the (anti)d - (anti)u asymmetry from charged pion DIS multiplicities. We also show that it is the exclusive- ρ 0 channel which accounts for the experimentally observed effect of the excess of charged over neutral pions produced at large z. (author)
Kinematic mounting systems for NSLS beamlines and experiments
International Nuclear Information System (INIS)
Oversluizen, T.; Stoeber, W.; Johnson, E.D.
1991-01-01
Methods for kinematically mounting equipment are well established, but applications at synchrotron radiation facilities are subject to constraints not always encountered in more traditional laboratory settings. Independent position adjustment of beamline components can have significant benefits in terms of minimizing time spent aligning, and maximizing time spent acquiring data. In this paper, we use examples taken from beamlines at the NSLS to demonstrate approaches for optimization of the reproducibility, stability, excursion, and set-up time for various situations. From our experience, we extract general principles which we hope will be useful for workers at other synchrotron radiation facilities. 7 refs., 4 figs
Inverse Dynamic Analysis for Various Drivings in Kinematic Systems
Energy Technology Data Exchange (ETDEWEB)
Lee, Byung Hoon [Pusan Nat’l Univ., Busan (Korea, Republic of)
2017-09-15
Analysis of actuating forces and joint reaction forces are essential to determine the capacity of actuators, to control the mechanical system and to design its components. This paper presents an algorithm that calculates actuating forces(or torques), depending on the various types of driving constraints, in order to produce a given system motion in the joint coordinate space. The joint coordinates are used as the generalized coordinates of a kinematic system. System equations of motion and constraint acceleration equations are transformed from the Cartesian coordinate space to the joint coordinate space using the velocity transformation method. A numerical example is carried out to verify the algorithm proposed.
Kinematic simulation and analysis of robot based on MATLAB
Liao, Shuhua; Li, Jiong
2018-03-01
The history of industrial automation is characterized by quick update technology, however, without a doubt, the industrial robot is a kind of special equipment. With the help of MATLAB matrix and drawing capacity in the MATLAB environment each link coordinate system set up by using the d-h parameters method and equation of motion of the structure. Robotics, Toolbox programming Toolbox and GUIDE to the joint application is the analysis of inverse kinematics and path planning and simulation, preliminary solve the problem of college students the car mechanical arm positioning theory, so as to achieve the aim of reservation.
A Kinematic Conservation Law in Free Surface Flow
Gavrilyuk , Sergey; Kalisch , Henrik; Khorsand , Zahra
2015-01-01
The Green-Naghdi system is used to model highly nonlinear weakly dispersive waves propagating at the surface of a shallow layer of a perfect fluid. The system has three associated conservation laws which describe the conservation of mass, momentum, and energy due to the surface wave motion. In addition, the system features a fourth conservation law which is the main focus of this note. It will be shown how this fourth conservation law can be interpreted in terms of a concrete kinematic quanti...
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.
Kinematics analysis technique fouettes 720° classic ballet.
Directory of Open Access Journals (Sweden)
Li Bo
2011-07-01
Full Text Available Athletics practice proved that the more complex the item, the more difficult technique of the exercises. Fouettes at 720° one of the most difficult types of the fouettes. Its implementation is based on high technology during rotation of the performer. To perform this element not only requires good physical condition of the dancer, but also requires possession correct technique dancer. On the basis corresponding kinematic theory in this study, qualitative analysis and quantitative assessment of fouettes at 720 by the best Chinese dancers. For analysis, was taken the method of stereoscopic images and the theoretical analysis.
Finite correlation time effects in kinematic dynamo problem
International Nuclear Information System (INIS)
Schekochihin, A.A.; Kulsrud, R.M.
2000-01-01
One-point statistics of the magnetic fluctuations in kinematic regime with large Prandtl number and non delta-correlated in time advecting velocity field are studied. A perturbation expansion in the ratio of the velocity correlation time to the dynamo growth time is constructed in the spirit of the Kliatskin-Tatarskii functional method and carried out to first order. The convergence properties are improved compared to the commonly used van Kampen-Terwiel method. The zeroth-order growth rate of the magnetic energy is estimated to be reduced (in three dimensions) by approximately 40%. This reduction is quite close to existing numerical results
Cluster mislocation in kinematic Sunyaev-Zel'dovich effect extraction
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.
Kinematics and age of 15 stars-photometric solar analogs
Galeev, A. I.; Shimansky, V. V.
2008-03-01
The radial and space velocities are inferred for 15 stars that are photometric analogs of the Sun. The space velocity components (U, V, W) of most of these stars lie within the 10-60 km/s interval. The star HD 225239, which in our previous papers we classified as a subgiant, has a space velocity exceeding 100 km/s, and belongs to the thick disk. The inferred fundamental parameters of the atmospheres of solar analogs are combined with published evolutionary tracks to estimate the masses and ages of the stars studied. The kinematics of photometric analogs is compared to the data for a large group of solar-type stars.
Bearing Capacity of the Working Platform with Kinematic Method
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Białek Katarzyna
2015-03-01
Full Text Available Bearing capacity of the working platform for heavy tracks was analysed using Distinct Layout Optimization (DLO method. The platform layer constructed from cohesionless soils is resting on weak cohesive subgrade. Different thickness of the platform, its effective angle of internal friction and undrained shear strength of the soft soil were taken into consideration. Kinematic method permits different failure mechanisms to be analyzed. Margin of safety for a given load and subsoil conditions was determined using two approaches: increasing the load or decreasing the shear strength up to failure. The results were compared with solution proposed in BRE recommendations.
The Glasgow-Maastricht foot model, evaluation of a 26 segment kinematic model of the foot
Oosterwaal, Michiel; Carbes, Sylvain; Telfer, Scott; Woodburn, James; T?rholm, S?ren; Al-Munajjed, Amir A.; van Rhijn, Lodewijk; Meijer, Kenneth
2016-01-01
Background Accurately measuring of intrinsic foot kinematics using skin mounted markers is difficult, limited in part by the physical dimensions of the foot. Existing kinematic foot models solve this problem by combining multiple bones into idealized rigid segments. This study presents a novel foot model that allows the motion of the 26 bones to be individually estimated via a combination of partial joint constraints and coupling the motion of separate joints using kinematic rhythms. Methods ...
Scattering of massless vector, tensor, and other particles in string theory at high energy
International Nuclear Information System (INIS)
Antonov, E.N.
1990-01-01
The 2 → 2 and 2 → 3 processes are studied in the multi-Regge kinematics for gluons and gravitons, the first excited states of the open and closed strings. The factorization of the corresponding amplitudes is demonstrated. Explicit relations generalizing the Low-Gribov expressions are obtained in the kinematics where one of the external particles is produced with small transverse momentum. The expressions in the limit α' → 0 coincide with the results of Yang-Mills theory and gravitation at high energies
Improved Inverse Kinematics Algorithm Using Screw Theory for a Six-DOF Robot Manipulator
Chen, Qingcheng; Zhu, Shiqiang; Zhang, Xuequn
2015-01-01
Based on screw theory, a novel improved inverse-kinematics approach for a type of six-DOF serial robot, “Qianjiang I”, is proposed in this paper. The common kinematics model of the robot is based on the Denavit-Hartenberg (D-H) notation method while its inverse kinematics has inefficient calculation and complicated solution, which cannot meet the demands of online real-time application. To solve this problem, this paper presents a new method to improve the efficiency of the inverse kinematics...
pynoddy 1.0: an experimental platform for automated 3-D kinematic and potential field modelling
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.
Whitfield, Jason A; Dromey, Christopher; Palmer, Panika
2018-04-18
The purpose of this study was to examine the effect of speech intensity on acoustic and kinematic vowel space measures and conduct a preliminary examination of the relationship between kinematic and acoustic vowel space metrics calculated from continuously sampled lingual marker and formant traces. Young adult speakers produced 3 repetitions of 2 different sentences at 3 different loudness levels. Lingual kinematic and acoustic signals were collected and analyzed. Acoustic and kinematic variants of several vowel space metrics were calculated from the formant frequencies and the position of 2 lingual markers. Traditional metrics included triangular vowel space area and the vowel articulation index. Acoustic and kinematic variants of sentence-level metrics based on the articulatory-acoustic vowel space and the vowel space hull area were also calculated. Both acoustic and kinematic variants of the sentence-level metrics significantly increased with an increase in loudness, whereas no statistically significant differences in traditional vowel-point metrics were observed for either the kinematic or acoustic variants across the 3 loudness conditions. In addition, moderate-to-strong relationships between the acoustic and kinematic variants of the sentence-level vowel space metrics were observed for the majority of participants. These data suggest that both kinematic and acoustic vowel space metrics that reflect the dynamic contributions of both consonant and vowel segments are sensitive to within-speaker changes in articulation associated with manipulations of speech intensity.
Langenderfer, Joseph E; Rullkoetter, Paul J; Mell, Amy G; Laz, Peter J
2009-04-01
An accurate assessment of shoulder kinematics is useful for understanding healthy normal and pathological mechanics. Small variability in identifying and locating anatomical landmarks (ALs) has potential to affect reported shoulder kinematics. The objectives of this study were to quantify the effect of landmark location variability on scapular and humeral kinematic descriptions for multiple subjects using probabilistic analysis methods, and to evaluate the consistency in results across multiple subjects. Data from 11 healthy subjects performing humeral elevation in the scapular plane were used to calculate Euler angles describing humeral and scapular kinematics. Probabilistic analyses were performed for each subject to simulate uncertainty in the locations of 13 upper-extremity ALs. For standard deviations of 4 mm in landmark location, the analysis predicted Euler angle envelopes between the 1 and 99 percentile bounds of up to 16.6 degrees . While absolute kinematics varied with the subject, the average 1-99% kinematic ranges for the motion were consistent across subjects and sensitivity factors showed no statistically significant differences between subjects. The description of humeral kinematics was most sensitive to the location of landmarks on the thorax, while landmarks on the scapula had the greatest effect on the description of scapular elevation. The findings of this study can provide a better understanding of kinematic variability, which can aid in making accurate clinical diagnoses and refining kinematic measurement techniques.
A Closed Loop Inverse Kinematics Solver Intended for Offline Calculation Optimized with GA
Directory of Open Access Journals (Sweden)
Emil Dale Bjoerlykhaug
2018-01-01
Full Text Available This paper presents a simple approach to building a robotic control system. Instead of a conventional control system which solves the inverse kinematics in real-time as the robot moves, an alternative approach where the inverse kinematics is calculated ahead of time is presented. This approach reduces the complexity and code necessary for the control system. Robot control systems are usually implemented in low level programming language. This new approach enables the use of high level programming for the complex inverse kinematics problem. For our approach, we implement a program to solve the inverse kinematics, called the Inverse Kinematics Solver (IKS, in Java, with a simple graphical user interface (GUI to load a file with desired end effector poses and edit the configuration of the robot using the Denavit-Hartenberg (DH convention. The program uses the closed-loop inverse kinematics (CLIK algorithm to solve the inverse kinematics problem. As an example, the IKS was set up to solve the kinematics for a custom built serial link robot. The kinematics for the custom robot is presented, and an example of input and output files is also presented. Additionally, the gain of the loop in the IKS is optimized using a GA, resulting in almost a 50% decrease in computational time.
Inverse kinematics of a dual linear actuator pitch/roll heliostat
Freeman, Joshua; Shankar, Balakrishnan; Sundaram, Ganesh
2017-06-01
This work presents a simple, computationally efficient inverse kinematics solution for a pitch/roll heliostat using two linear actuators. The heliostat design and kinematics have been developed, modeled and tested using computer simulation software. A physical heliostat prototype was fabricated to validate the theoretical computations and data. Pitch/roll heliostats have numerous advantages including reduced cost potential and reduced space requirements, with a primary disadvantage being the significantly more complicated kinematics, which are solved here. Novel methods are applied to simplify the inverse kinematics problem which could be applied to other similar problems.
International Nuclear Information System (INIS)
Tornow, W.; Braun, R.T.; Witala, H.
1996-01-01
We review published analyses of the final-state-interaction enhancement observed in proton energy distributions obtained from kinematically incomplete neutron-deuteron breakup experiments. We compare the results derived from these analyses for the neutron-neutron scattering length, a nn with our results based on a rigorous treatment of the three-nucleon Faddeev equations in conjunction with the use of realistic nucleon-nucleon potentials. Our values for a nn deviate outside the quoted uncertainties from the ones obtained in the previous analyses where simplified nucleon-nucleon interaction models were employed. In contrast to the previous determinations, the present results for a nn are in clear disagreement with the values for a nn based on π - -deuteron capture experiments. Unless inconsistencies in the experimental neutron-deuteron breakup data at low energies can be resolved and the influence of possible three-nucleon-force effects can be reliably determined, we recommend that one not resort to the kinematically incomplete neutron-deuteron breakup reaction as a tool for determining a quantity as important for nuclear and particle physics as is the neutron-neutron scattering length a nn . (author)
Fermilab | Science | Particle Physics
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Using robotics in kinematics classes: exploring braking and stopping distances
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.
Kinematic structure at the early flight position in ski jumping.
Vodičar, Janez; Coh, Milan; Jošt, Bojan
2012-12-01
The purpose of our research was to establish the variability of correlation between the length of the jumps and selected multi-item kinematic variables (n=9) in the early flight phase technique of ski jumping. This study was conducted on a sample of elite Slovenian ski jumpers (N=29) who participated in the experiment on a jumping hill in Hinterzarten, Germany (HS95m) on the 20(th) of August, 2008. The highest and most significant correlations (p=0.01) with the length of the ski jump were found in the multi-item variable height of flying, which was also expressed with the highest level of stability of the explained total variance (TV) on the first factor (TV=69.13%). The most important characteristic of the aerodynamic aspect of early flight was the variable angle between the body chord and the horizontal axis with significantly high correlations (pjump. Only two more variables, the angle between the upper body and the horizontal plane (TV=53.69%), and the angle between left ski and left leg (TV=50.13%), had an explained common variance on the first factor greater than 50% of total variance. The results indicated that some kinematic parameters of ski jumping early flight technique were more important for success considering the length of the jump.
Observability of planet-disc interactions in CO kinematics
Pérez, Sebastián; Casassus, S.; Benítez-Llambay, P.
2018-06-01
Empirical evidence of planets in gas-rich circumstellar discs is required to constrain giant planet formation theories. Here we study the kinematic patterns which arise from planet-disc interactions and their observability in CO rotational emission lines. We perform three-dimensional hydrodynamical simulations of single giant planets, and predict the emergent intensity field with radiative transfer. Pressure gradients at planet-carved gaps, spiral wakes and vortices bear strong kinematic counterparts. The iso-velocity contours in the CO(2-1) line centroids vo reveal large-scale perturbations, corresponding to abrupt transitions from below sub-Keplerian to super-Keplerian rotation along with radial and vertical flows. The increase in line optical depth at the edge of the gap also modulates vo, but this is a mild effect compared to the dynamical imprint of the planet-disc interaction. The large-scale deviations from the Keplerian rotation thus allow the planets to be indirectly detected via the first moment maps of molecular gas tracers, at ALMA angular resolutions. The strength of these deviations depends on the mass of the perturber. This initial study paves the way to eventually determine the mass of the planet by comparison with more detailed models.
Kinematics of a Hybrid Manipulator by Means of Screw Theory
International Nuclear Information System (INIS)
Gallardo-Alvarado, J
2005-01-01
In this work the kinematics of a hybrid manipulator, namely a fully parallel-serial manipulator, with a particular topology is approached by means of the theory of screws. Given the length of the six independent limbs, the forward position analysis of the mechanism under study, indeed the computation of the resulting pose, position and orientation, of the end-platform with respect to the fixed platform, is carried out in closed-form solution. Therefore conveniently this initial analysis avoids the use of a numerical technique such as the Newton-Raphson method. Writing in screw form the reduced acceleration state of the translational platform, with respect to the fixed platform, a simple expression for the computation of the acceleration of the translational platform is derived by taking advantage of the properties of reciprocal screws, via the Klein form, a bilinear symmetric form of the Lie algebra e(3). Following a similar procedure, a simple expression for the computation of the angular acceleration of the end-platform, with respect to the translational platform, is easily derived. Naturally, as an intermediate step, this contribution also provides the forward and inverse velocity analyses of the chosen parallel-serial manipulator. Finally, in order to prove the versatility of the expressions obtained via screw theory for solving the kinematics, up to the acceleration analysis, of the proposed spatial mechanism, a numerical example is solved with the help of commercial computer codes
Hydrodynamic interactions in metachronal paddling: effects of varying stroke kinematics
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.
Efficient dynamic modeling of manipulators containing closed kinematic loops
Ferretti, Gianni; Rocco, Paolo
An approach to efficiently solve the forward dynamics problem for manipulators containing closed chains is proposed. The two main distinctive features of this approach are: the dynamics of the equivalent open loop tree structures (any closed loop can be in general modeled by imposing some additional kinematic constraints to a suitable tree structure) is computed through an efficient Newton Euler formulation; the constraint equations relative to the most commonly adopted closed chains in industrial manipulators are explicitly solved, thus, overcoming the redundancy of Lagrange's multipliers method while avoiding the inefficiency due to a numerical solution of the implicit constraint equations. The constraint equations considered for an explicit solution are those imposed by articulated gear mechanisms and planar closed chains (pantograph type structures). Articulated gear mechanisms are actually used in all industrial robots to transmit motion from actuators to links, while planar closed chains are usefully employed to increase the stiffness of the manipulators and their load capacity, as well to reduce the kinematic coupling of joint axes. The accuracy and the efficiency of the proposed approach are shown through a simulation test.
Design and test of a parallel kinematic solar tracker
Directory of Open Access Journals (Sweden)
Stefano Mauro
2015-12-01
Full Text Available This article proposes a parallel kinematic solar tracker designed for driving high-concentration photovoltaic modules. This kind of module produces energy only if they are oriented with misalignment errors lower than 0.4°. Generally, a parallel kinematic structure provides high stiffness and precision in positioning, so these features make this mechanism fit for the purpose. This article describes the work carried out to design a suitable parallel machine: an already existing architecture was chosen, and the geometrical parameters of the system were defined in order to obtain a workspace consistent with the requirements for sun tracking. Besides, an analysis of the singularities of the system was carried out. The method used for the singularity analysis revealed the existence of singularities which had not been previously identified for this kind of mechanism. From the analysis of the mechanism developed, very low nominal energy consumption and elevated stiffness were found. A small-scale prototype of the system was constructed for the first time. A control algorithm was also developed, implemented, and tested. Finally, experimental tests were carried out in order to verify the capability of the system of ensuring precise pointing. The tests have been considered passed as the system showed an orientation error lower than 0.4° during sun tracking.
KINEMATICS OF OUTER HALO GLOBULAR CLUSTERS IN M31
International Nuclear Information System (INIS)
Veljanoski, J.; Ferguson, A. M. N.; Bernard, E. J.; Peñarrubia, J.; Mackey, A. D.; Huxor, A. P.; Irwin, M. J.; Chapman, S. C.; Côté, P.; Tanvir, N. R.; McConnachie, A.; Ibata, R. A.; Martin, N. F.; Fardal, M.; Lewis, G. F.
2013-01-01
We present the first kinematic analysis of the far outer halo globular cluster (GC) population in the Local Group galaxy M31. Our sample contains 53 objects with projected radii of ∼20-130 kpc, 44 of which have no previous spectroscopic information. GCs with projected radii ∼> 30 kpc are found to exhibit net rotation around the minor axis of M31, in the same sense as the inner GCs, albeit with a smaller amplitude of 79 ± 19 km s –1 . The rotation-corrected velocity dispersion of the full halo GC sample is 106 ± 12 km s –1 , which we observe to decrease with increasing projected radius. We find compelling evidence for kinematic coherence among GCs that project on top of halo substructure, including a clear signature of infall for GCs lying along the northwest stream. Using the tracer mass estimator, we estimate the dynamical mass of M31 within 200 kpc to be M M31 = (1.2-1.5) ± 0.2 × 10 12 M ☉ . This value is highly dependent on the chosen model and assumptions within.
Kinematics of self-initiated and reactive karate punches.
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.
Joint Kinetics and Kinematics During Common Lower Limb Rehabilitation Exercises.
Comfort, Paul; Jones, Paul Anthony; Smith, Laura Constance; Herrington, Lee
2015-10-01
Unilateral body-weight exercises are commonly used to strengthen the lower limbs during rehabilitation after injury, but data comparing the loading of the limbs during these tasks are limited. To compare joint kinetics and kinematics during 3 commonly used rehabilitation exercises. Descriptive laboratory study. Laboratory. A total of 9 men (age = 22.1 ± 1.3 years, height = 1.76 ± 0.08 m, mass = 80.1 ± 12.2 kg) participated. Participants performed the single-legged squat, forward lunge, and reverse lunge with kinetic data captured via 2 force plates and 3-dimensional kinematic data collected using a motion-capture system. Peak ground reaction forces, maximum joint angles, and peak sagittal-joint moments. We observed greater eccentric and concentric peak vertical ground reaction forces during the single-legged squat than during both lunge variations (P ≤ .001). Both lunge variations demonstrated greater knee and hip angles than did the single-legged squat (P .05). Greater dorsiflexion occurred during the single-legged squat than during both lunge variations (P reverse lunge (P = .003) and the single-legged squat (P = .011). Knee-joint moments were greater in the single-legged squat than in the reverse lunge (P reverse lunge (P reverse lunge and then the forward lunge. In contrast, loading progressions for the knee and ankle should begin with the reverse lunge and progress to the forward lunge and then the single-legged squat.
Kinematics and kinetics of elite windmill softball pitching.
Werner, Sherry L; Jones, Deryk G; Guido, John A; Brunet, Michael E
2006-04-01
A significant number of time-loss injuries to the upper extremity in elite windmill softball pitchers has been documented. The number of outings and pitches thrown in 1 week for a softball pitcher is typically far in excess of those seen in baseball pitchers. Shoulder stress in professional baseball pitching has been reported to be high and has been linked to pitching injuries. Shoulder distraction has not been studied in an elite softball pitching population. The stresses on the throwing shoulder of elite windmill pitchers are similar to those found for professional baseball pitchers. Descriptive laboratory study. Three-dimensional, high-speed (120 Hz) video data were collected on rise balls from 24 elite softball pitchers during the 1996 Olympic Games. Kinematic parameters related to pitching mechanics and resultant kinetics on the throwing shoulder were calculated. Multiple linear regression analysis was used to relate shoulder stress and pitching mechanics. Shoulder distraction stress averaged 80% of body weight for the Olympic pitchers. Sixty-nine percent of the variability in shoulder distraction can be explained by a combination of 7 parameters related to pitching mechanics. Excessive distraction stress at the throwing shoulder is similar to that found in baseball pitchers, which suggests that windmill softball pitchers are at risk for overuse injuries. Normative information regarding upper extremity kinematics and kinetics for elite softball pitchers has been established.
Classical kinematic model for direct reactions of oriented reagents
International Nuclear Information System (INIS)
Schechter, I.; Prisant, M.G.; Levine, R.D.
1987-01-01
A simple kinematic model based on the concept of an orientation-dependent critical configuration for reaction is introduced and applied. The model serves two complementary purposes. In the predictive mode the model provides an easily implemented procedure for computing the reactivity of oriented reagents (including those actually amenable to measure) from a given potential energy surface. The predictions of the model are compared against classical trajectory results for the H + D 2 reaction. By use of realistic potential energy surfaces the model is applied to the Li + HF and O + HCl reactions where the HX molecules are pumped by a polarized laser. A given classical trajectory is deemed reactive or not according to whether it can surmount the barrier at that particular orientation. The essential difference with the model of Levine and Bernstein is that the averaging over initial conditions is performed by using a Monte Carlo integration. One can therefore use the correct orientation-dependent shape (and not only height) of the barrier to reaction and, furthermore, use oriented or aligned reagents. Since the only numerical step is a Monte Carlo sampling of initial conditions, very many trajectories can be run. This suffices to determine the reaction cross section for different initial conditions. To probe the products, they have employed the kinematic approach of Elsum and Gordon. The result is a model where, under varying initial conditions, examining final-state distributions or screening different potential energy surfaces can be efficiently carried out
The development of computational algorithms for manipulator inverse kinematics
International Nuclear Information System (INIS)
Sasaki, Shinobu
1989-10-01
A solution technique of the inverse kinematics for multi-joint robot manipulators has been considered to be one of the most cumbersome treatment due to non-linearity properties inclusive of trigonometric functions. The most traditional approach is to use the Jacobian matrix on linearization assumptions. This iterative technique, however, is attended with numerical problems having significant influences on the solution characteristics such as initial guess dependence and singularities. Taking these facts into consideration, new approaches have been proposed from different standpoints, which are based on polynomial transformation of kinematic model, the minimization technique in mathematical programming, vector-geometrical concept, and the separation of joint variables associated with the optimization problem. In terms of computer simulations, each approach was identified to be a useful algorithm which leads to theoretically accurate solutions to complicated inverse problems. In this way, the short-term goal of our studies on manipulator inverse problem in the R and D project of remote handling technology was accomplished with success, and consequently the present report sums up the results of basic studies on this matter. (author)
Observation of top quark production using kinematic techniques
Energy Technology Data Exchange (ETDEWEB)
Kim, Shinhong [Tsukuba Univ., Ibaraki (Japan); CDF Collaboration
1995-05-17
We present analysis results of the top quark production using kinematic techniques in p{bar p} collisions at {radical}s = 1.8 TeV with the Collider Detector at Fermilab (CDF). We analyzed a data sample corresponding to an integrated luminosity of 67 pb{sup {minus}1}. First, we compare the kinematic properties, the second and third leading jet E{sub T} of W+ > 3 jet events with expectations for t{bar t} production and its back-ground processes, predominantly direct W + jet production. The probability that backgrounds fake the excess in the signal region was found to be less than 0.26%. Next, we use a scaler sum of the transverse energies of the lepton, neutrino and jets in W+{ge}4 jet events. This analysis shows t{bar t} events exist significantly in the event sample, and enables us to estimate the top quark mass to be M{sub top} = 180 {plus_minus} 12 {sub {minus}15}{sup +19} GeV/c{sup 2}. Finally, we analyse the dijet invariant mass in the W+{ge}4 jet events. It shows a significant mass peak consistent with a mass peak of W decaying into dijet. From these results and counting experiment, we have confirmed previous evidence reported in 1994 April and observed top quark production.
Kinematic viscosity of liquid Al-Cu alloys
International Nuclear Information System (INIS)
Konstantinova, N Yu; Popel, P S
2008-01-01
Temperature dependences of kinematic viscosity n of liquid Al 100-x -Cu x alloys (x = 0.0, 10.0, 17.1, 25.0, 32.2, 40.0 and 50.0 at.%) were measured. A technique based on registration of the period and the decrement of damping of rotating oscillations of a cylindrical crucible with a melt was used. Viscosity was calculated in low viscous liquids approximation. Measurements were carried out in vacuum in crucibles of BeO with a temperature step of 30 deg. C and isothermal expositions of 10 to 15 minutes during both heating up to 1100-1250 deg. C and subsequent cooling. We have discovered branching of heating and cooling curves v(T) (hysteresis of viscosity) below temperatures depending on the copper content: 950 deg. C at 10 and 17.1 at.% Cu, 1050 deg. C at 25 and 40 at.% Cu, 850 deg. C at 32.2 at.% Cu. For samples with 10 and 17.1 at.% Cu the cooling curve 'returns' to the heating one near 700 deg. C. An abnormally high spreading of results at repeated decrement measurements was fixed at heating of the alloy containing 50 at.% Cu above 1000 deg. C. During subsequent cooling the effect disappeared. Isotherms of kinematic viscosity have been fitted for several temperatures
STAMPS: development and verification of swallowing kinematic analysis software.
Lee, Woo Hyung; Chun, Changmook; Seo, Han Gil; Lee, Seung Hak; Oh, Byung-Mo
2017-10-17
Swallowing impairment is a common complication in various geriatric and neurodegenerative diseases. Swallowing kinematic analysis is essential to quantitatively evaluate the swallowing motion of the oropharyngeal structures. This study aims to develop a novel swallowing kinematic analysis software, called spatio-temporal analyzer for motion and physiologic study (STAMPS), and verify its validity and reliability. STAMPS was developed in MATLAB, which is one of the most popular platforms for biomedical analysis. This software was constructed to acquire, process, and analyze the data of swallowing motion. The target of swallowing structures includes bony structures (hyoid bone, mandible, maxilla, and cervical vertebral bodies), cartilages (epiglottis and arytenoid), soft tissues (larynx and upper esophageal sphincter), and food bolus. Numerous functions are available for the spatiotemporal parameters of the swallowing structures. Testing for validity and reliability was performed in 10 dysphagia patients with diverse etiologies and using the instrumental swallowing model which was designed to mimic the motion of the hyoid bone and the epiglottis. The intra- and inter-rater reliability tests showed excellent agreement for displacement and moderate to excellent agreement for velocity. The Pearson correlation coefficients between the measured and instrumental reference values were nearly 1.00 (P software is expected to be useful for researchers who are interested in the swallowing motion analysis.
Quantification of toy sword kinematics with male pediatric volunteers.
Beeman, Stephanie M; Rowson, Steven; Duma, Stefan M
2014-01-01
While extensive research in toy safety has been performed, data is unavailable with regard to the kinematics of toy swords. To improve upon design criteria, knowledge of a childs physical capacity is essential. The purpose of this study was to quantify the linear and angular velocities generated by children swinging toy swords. A total of 36 male subjects, ages 4-14 years old, each participated in one trial. Subjects were instructed to swing a toy sword as fast and hard as possible for ~10 seconds. A Vicon motion analysis system was used to capture subject and sword kinematics. Peak linear and angular sword velocities were calculated. A strong correlation was identified between age and velocity. The 8-14 year old males were not significantly different. The 4 year old males generated significantly lower velocities than the 8-14 year old males. The 6 year old males produced significantly lower velocities than the 10- 14 year old males. It was concluded that age had a significant effect on the linear and angular velocities generated by children. The trends observed within this study likely result from typical pediatric and adolescent development. By accounting for the physical capabilities of a specific population, toys can be designed with decreased inherent risks of injury.
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.
Motor resonance facilitates movement execution: an ERP and kinematic study
Directory of Open Access Journals (Sweden)
Mathilde eMénoret
2013-10-01
Full Text Available Action observation, simulation and execution share neural mechanisms that allow for a common motor representation. It is known that when these overlapping mechanisms are simultaneously activated by action observation and execution, motor performance is influenced by observation and vice versa. To understand the neural dynamics underlying this influence and to measure how variations in brain activity impact the precise kinematics of motor behaviour, we coupled kinematics and electrophysiological recordings of participants while they performed and observed congruent or non-congruent actions or during action execution alone. We found that movement velocities and the trajectory deviations of the executed actions increased during the observation of congruent actions compared to the observation of non-congruent actions or action execution alone. This facilitation was also discernible in the motor-related potentials of the participants; the motor-related potentials were transiently more negative in the congruent condition around the onset of the executed movement, which occurred 300 ms after the onset of the observed movement. This facilitation seemed to depend not only on spatial congruency but also on the optimal temporal relationship of the observation and execution events.
Static and kinematic positioning using WADGPS from geostationary satellites
Cefalo, R.; Gatti, M.
2003-04-01
STATIC AND KINEMATIC POSITIONING USING WADGPS CORRECTIONS FROM GEOSTATIONARY SATELLITES Cefalo R. (1), Gatti M (2) (1) Department of Civil Engineering, University of Trieste, P.le Europa 1, 34127 Trieste, Italy, cefalo@dic.univ.trieste.it, (2) Department of Engineering, University of Ferrara, via Saragat 1, 44100 Ferrara, Italy, mgatti@ing.unife.it ABSTRACT. Starting from February 2000, static and kinematic experiments have been performed at the Department of Civil Engineering of University of Trieste, Italy and the Department of Engineering of University of Ferrara, Italy, using the WADGPS (Wide Area Differential GPS) corrections up linked by Geostationary Satellites belonging to the American WAAS and European EGNOS. Recently, a prototypal service by ESA (European Space Agency) named SISNet (Signal In Space through Internet), has been introduced using Internet to diffuse the messages up linked through AOR-E and IOR Geostationary Satellites. This service will overcome the problems relative to the availability of the corrections in urban areas. This system is currently under tests by the authors in order to verify the latency of the message and the applicability and accuracies obtainable in particular in dynamic applications.
Barefoot running and hip kinematics: good news for the knee?
McCarthy, Colm; Fleming, Neil; Donne, Bernard; Blanksby, Brian
2015-05-01
Patellofemoral pain and iliotibial band syndromes are common running injuries. Excessive hip adduction (HADD), hip internal rotation (HIR), and contralateral pelvic drop (CLPD) during running have been suggested as causes of injury in female runners. This study compared these kinematic variables during barefoot and shod running. Three-dimensional gait analyses of 23 habitually shod, uninjured female recreational athletes running at 3.33 m·s while shod and barefoot were studied. Spatiotemporal and kinematic data at initial contact (IC), 10% of stance (corresponding to the vertical impact peak), and peak angles were collected from each participant for HADD, HIR, and CLPD, and differences were compared across footwear conditions. Step rates when running barefoot were 178 ± 13 versus 172 ± 11 steps per minute when shod (P strike patterns changed from a group mean heel-toe latency indicating a rear-foot strike (20.8 ms) when shod, to one indicating a forefoot strike (-1.1 ms) when barefoot (P knee injuries in female runners, barefoot running could have potential for injury prevention or treatment in this cohort.
A hybrid press system: Motion design and inverse kinematics issues
Directory of Open Access Journals (Sweden)
M. Erkan Kütük
2016-06-01
Full Text Available A hybrid machine (HM is a system integrating two types of motor; servo and constant velocity with a mechanism. The purpose is to make use of the energy in the system efficiently with a flexible system having more than one degree of freedom (DOF. A review is included on hybrid press systems. This study is included as a part of an industrial project used for metal forming. The system given here includes a 7 link mechanism, one of link is driven by a constant velocity motor (CV and the other is driven by a servo motor (SM. Kinematics analysis of the hybrid driven mechanism is presented here as inverse kinematics analysis. Motion design is very crucial step when using a hybrid machine. So motion design procedure is given with motion curve examples needed. Curve Fitting Toolbox (CFT in Matlab® is offered as an auxiliary method which can be successfully applied. Motion characteristics are chosen by looking at requirements taken from metal forming industry. Results are then presented herein.
Kinematics at the Main Mechanism of a Railbound Forging Manipulator
Directory of Open Access Journals (Sweden)
Florian Ion Tiberiu Petrescu
2015-09-01
Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Heavy payload forging manipulators are mainly characterized by large load output and large capacitive load input. The relationship between outputs and inputs will greatly influence the control and the reliability. Forging manipulators have become more prevalent in the industry today. They are used to manipulate objects to be forged. The most common forging manipulators are moving on a railway to have a greater precision and stability. They have been called the railbound forging manipulators. In this paper we analyze the general kinematics of the main mechanism from a such manipulator. Kinematic scheme shows a typical forging manipulator, with the basic motions in operation process: walking, motion of the tong and buffering. The lifting mechanism consists of several parts including linkages, hydraulic drives and motion pairs. The principle of type design from the viewpoints of the relationship between output characteristics and actuator inputs is discussed. An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed. These novel forging manipulators which satisfy certain functional requirements provide an effective help for the design of forging manipulators.
Temperature dependent kinematic viscosity of different types of engine oils
Directory of Open Access Journals (Sweden)
Libor Severa
2009-01-01
Full Text Available The objective of this study is to measure how the viscosity of engine oil changes with temperature. Six different commercially distributed engine oils (primarily intended for motorcycle engines of 10W–40 viscosity grade have been evaluated. Four of the oils were of synthetic type, two of semi–synthetic type. All oils have been assumed to be Newtonian fluids, thus flow curves have not been determined. Oils have been cooled to below zero temperatures and under controlled temperature regulation, kinematic viscosity (mm2 / s have been measured in the range of −5 °C and +115 °C. Anton Paar digital viscometer with concentric cylinders geometry has been used. In accordance with expected behavior, kinematic viscosity of all oils was decreasing with increasing temperature. Viscosity was found to be independent on oil’s density. Temperature dependence has been modeled using several mathematical models – Vogel equation, Arrhenius equation, polynomial, and Gaussian equation. The best match between experimental and computed data has been achieved for Gaussian equation (R2 = 0.9993. Knowledge of viscosity behavior of an engine oil as a function of its temperature is of great importance, especially when considering running efficiency and performance of combustion engines. Proposed models can be used for description and prediction of rheological behavior of engine oils.
A method to estimate stellar ages from kinematical data
Almeida-Fernandes, F.; Rocha-Pinto, H. J.
2018-05-01
We present a method to build a probability density function (PDF) for the age of a star based on its peculiar velocities U, V, and W and its orbital eccentricity. The sample used in this work comes from the Geneva-Copenhagen Survey (GCS) that contains the spatial velocities, orbital eccentricities, and isochronal ages for about 14 000 stars. Using the GCS stars, we fitted the parameters that describe the relations between the distributions of kinematical properties and age. This parametrization allows us to obtain an age probability from the kinematical data. From this age PDF, we estimate an individual average age for the star using the most likely age and the expected age. We have obtained the stellar age PDF for the age of 9102 stars from the GCS and have shown that the distribution of individual ages derived from our method is in good agreement with the distribution of isochronal ages. We also observe a decline in the mean metallicity with our ages for stars younger than 7 Gyr, similar to the one observed for isochronal ages. This method can be useful for the estimation of rough stellar ages for those stars that fall in areas of the Hertzsprung-Russell diagram where isochrones are tightly crowded. As an example of this method, we estimate the age of Trappist-1, which is a M8V star, obtaining the age of t(UVW) = 12.50(+0.29 - 6.23) Gyr.
Inverse-kinematics study of 78Kr + 40Ca at 10 AMeV
Directory of Open Access Journals (Sweden)
Henry E.
2015-01-01
Full Text Available The CHIMERA multi-detector array at LNS Catania has been used to study the inverse-kinematics reaction of 78Kr + 40Ca at a bombarding energy of 10 A MeV. Analysis of the experimental data focused on a class of selected events consistent with the complete fusion and subsequent binary split of the of the reacting system. This class of events features a broad A, Z distribution of fission fragments centered about symmetric fission while exhibiting relative velocities significantly higher than given by Viola systematics. The center-of-mass angular distribution (dσ/dΘ of the fission fragments exhibit an unexpected anisotropy inconsistent with a compound-nucleus reaction and indicates a dynamic fusion-fission like process. The observed angular distribution features an asymmetric forward-backward peaking most prevalent for mass-asymmetric events. Furthermore, the more massive fragment of mass-asymmetric events appears to emerge preferentially in the forward direction, along the beam axis, in analogy to dynamic fragmentation of projectile-like fragments. Analysis of the angular distribution of alpha particles emitted from these fission fragments suggests the events are associated mostly with central collisions.
International Nuclear Information System (INIS)
Gaisser, T.K.; Shafi, Q.; Barr, S.M.; Seckel, D.; Rusjan, E.; Fletcher, R.S.
1991-01-01
This report discusses research of professor at Bartol research institute in the following general areas: particle phenomenology and non-accelerator physics; particle physics and cosmology; theories with higher symmetry; and particle astrophysics and cosmology
Energy Technology Data Exchange (ETDEWEB)
Daniali, H. M.; Dardel, M.; Fathi, A. [Babol University of Technology, Babol (Iran, Islamic Republic of); Varedi, S. M. [University of Shahrood, Shahrood (Iran, Islamic Republic of)
2015-05-15
In practice, clearances in the joints are inevitable due to tolerances and defects arising from design and manufacturing. Moreover, the joints undergo wear and backlash, resulting in poor accuracy and repeatability. This paper presents a novel optimization method for simultaneously kinematic and dynamic synthesis of a planar four-bar linkage with clearance at the joints. It is well-known that in the presence of clearance at a joint, the linkage gains an additional, uncontrollable degree of freedom which is the source of error. Here, we synthesis the path generation problem while controlling the unwanted degrees of freedom by revising the mass distributions of the moving links. An algorithm based on particle swarm optimization method solves this highly nonlinear optimization problem with some constraints. Finally, an example is included to demonstrate the efficiency of the algorithm. The results clearly show that the linear and angular accelerations of the links for the optimal design are very smooth and bounded.
Wang, Mingming; Luo, Jianjun; Yuan, Jianping; Walter, Ulrich
2018-05-01
Application of the multi-arm space robot will be more effective than single arm especially when the target is tumbling. This paper investigates the application of particle swarm optimization (PSO) strategy to coordinated trajectory planning of the dual-arm space robot in free-floating mode. In order to overcome the dynamics singularities issue, the direct kinematics equations in conjunction with constrained PSO are employed for coordinated trajectory planning of dual-arm space robot. The joint trajectories are parametrized with Bézier curve to simplify the calculation. Constrained PSO scheme with adaptive inertia weight is implemented to find the optimal solution of joint trajectories while specific objectives and imposed constraints are satisfied. The proposed method is not sensitive to the singularity issue due to the application of forward kinematic equations. Simulation results are presented for coordinated trajectory planning of two kinematically redundant manipulators mounted on a free-floating spacecraft and demonstrate the effectiveness of the proposed method.
Graph Theory Roots of Spatial Operators for Kinematics and Dynamics
Jain, Abhinandan
2011-01-01
Spatial operators have been used to analyze the dynamics of robotic multibody systems and to develop novel computational dynamics algorithms. Mass matrix factorization, inversion, diagonalization, and linearization are among several new insights obtained using such operators. While initially developed for serial rigid body manipulators, the spatial operators and the related mathematical analysis have been shown to extend very broadly including to tree and closed topology systems, to systems with flexible joints, links, etc. This work uses concepts from graph theory to explore the mathematical foundations of spatial operators. The goal is to study and characterize the properties of the spatial operators at an abstract level so that they can be applied to a broader range of dynamics problems. The rich mathematical properties of the kinematics and dynamics of robotic multibody systems has been an area of strong research interest for several decades. These properties are important to understand the inherent physical behavior of systems, for stability and control analysis, for the development of computational algorithms, and for model development of faithful models. Recurring patterns in spatial operators leads one to ask the more abstract question about the properties and characteristics of spatial operators that make them so broadly applicable. The idea is to step back from the specific application systems, and understand more deeply the generic requirements and properties of spatial operators, so that the insights and techniques are readily available across different kinematics and dynamics problems. In this work, techniques from graph theory were used to explore the abstract basis for the spatial operators. The close relationship between the mathematical properties of adjacency matrices for graphs and those of spatial operators and their kernels were established. The connections hold across very basic requirements on the system topology, the nature of the component
Kinematic analysis for the implementation of landslide mitigation measures
Delmonaco, Giuseppe; Margottini, Claudio; Spizzichino, Daniele
2010-05-01
The present work is finalised at the implementation of a landslide risk mitigation master plan of the ancient citadel of Machu Picchu. After the warning launched in March 2001, by the scientific community on potential collapse of the citadel from a near-disastrous landslide event different studies have been promoted to reconstruct landslide activity and suggest landslide risk mitigation measures for the protection and conservation of Machu Picchu cultural heritage. A site-scale analysis has been implemented following the application and integration of geomechanical classifications, ambient noise measurements and structural and kinematical analysis. The geology of the area is characterized by granitoid bodies that had been emplaced in the axial zones of the main rift system that are now exposed at the highest altitudes, together with country rocks (Precambrian and Lower Paleozoic metamorphics) originally constituting the rift ‘roots'. The bedrock of the Inca citadel of Machu Picchu is mainly composed by granite and subordinately granodiorite. This is mainly located in the lower part of the slopes. Superficially, the granite is jointed in blocks with variable dimensions, promoted by local structural setting. Single blocks vary from 10-1 to about 200 m3. Soil cover, widely outcropping in the area, is mainly composed by individual blocks and subordinately by coarse materials originated by chemical and physical weathering of minerals. Regional tectonic uplift and structural setting rule the general morphological features of the area and as a consequence, landslide type and evolution. Rock falls, rock slides, debris flows and debris slides are the main landslide typologies affecting the citadel slopes. In the last mission in May 2009, elastic and deformation rock parameters have been collected using a passive seismic innovative technique based on natural microtremor measurements and geostructural scan lines elaboration. A landslide zoning of the citadel has been
Characterizing multisegment foot kinematics during gait in diabetic foot patients
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Denti Paolo
2009-10-01
Full Text Available Abstract Background The prevalence of diabetes mellitus has reached epidemic proportions, this condition may result in multiple and chronic invalidating long term complications. Among these, the diabetic foot, is determined by the simultaneous presence of both peripheral neuropathy and vasculopathy that alter the biomechanics of the foot with the formation of callosity and ulcerations. To diagnose and treat the diabetic foot is crucial to understand the foot complex kinematics. Most of gait analysis protocols represent the entire foot as a rigid body connected to the shank. Nevertheless the existing multisegment models cannot completely decipher the impairments associated with the diabetic foot. Methods A four segment foot and ankle model for assessing the kinematics of the diabetic foot was developed. Ten normal subjects and 10 diabetics gait patterns were collected and major sources of variability were tested. Repeatability analysis was performed both on a normal and on a diabetic subject. Direct skin marker placement was chosen in correspondence of 13 anatomical landmarks and an optoelectronic system was used to collect the data. Results Joint rotation normative bands (mean plus/minus one standard deviation were generated using the data of the control group. Three representative strides per subject were selected. The repeatability analysis on normal and pathological subjects results have been compared with literature and found comparable. Normal and pathological gait have been compared and showed major statistically significant differences in the forefoot and midfoot dorsi-plantarflexion. Conclusion Even though various biomechanical models have been developed so far to study the properties and behaviour of the foot, the present study focuses on developing a methodology for the functional assessment of the foot-ankle complex and for the definition of a functional model of the diabetic neuropathic foot. It is, of course, important to evaluate
Acceleration Kinematics in Cricketers: Implications for Performance in the Field
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G. Lockie Robert
2014-03-01
Full Text Available Cricket fielding often involves maximal acceleration to retrieve the ball. There has been no analysis of acceleration specific to cricketers, or for players who field primarily in the infield (closer to the pitch or outfield (closer to the boundary. This study analyzed the first two steps of a 10-m sprint in experienced cricketers. Eighteen males (age = 24.06 ± 4.87 years; height = 1.81 ± 0.06 m; mass = 79.67 ± 10.37 kg were defined as primarily infielders (n = 10 or outfielders (n = 8. Timing lights recorded 0-5 and 0-10 m time. Motion capture measured first and second step kinematics, including: step length; step frequency; contact time; shoulder motion; lead and rear arm elbow angle; drive leg hip and knee extension, and ankle plantar flexion; swing leg hip and knee flexion, and ankle dorsi flexion. A one-way analysis of variance (p < 0.05 determined between-group differences. Data was pooled for a Pearson’s correlation analysis (p < 0.05 to analyze kinematic relationships. There were no differences in sprint times, and few variables differentiated infielders and outfielders. Left shoulder range of motion related to second step length (r = 0.471. First step hip flexion correlated with both step lengths (r = 0.570-0.598, and frequencies (r = -0.504--0.606. First step knee flexion related to both step lengths (r = 0.528-0.682, and first step frequency (r = -0.669. First step ankle plantar flexion correlated with second step length (r = -0.692 and frequency (r = 0.726. Greater joint motion ranges related to longer steps. Cricketers display similar sprint kinematics regardless of fielding position, likely because players may field in the infield or outfield depending on match situation. Due to relationships with shoulder and leg motion, and the importance and trainability of step length, cricketers should target this variable to enhance acceleration.
Kinematic Analysis of the Standing Long Jump in Children 6- to 12-Years-Old
Fernandez-Santos, Jorge R.; Gonzalez-Montesinos, Jose Luis; Ruiz, Jonatan R.; Jiménez-Pavón, David; Castro-Piñero, Jose
2018-01-01
The purpose of this study was to analyze the kinematic variables that determine the performance of the standing long jump in children 6- to 12-years-old. There were 121 healthy children (58 girls) recorded while they performed the standing long jump test. All kinematic variables showed a significant correlation with calculated jump distance and…
Collision-free inverse kinematics of a 7 link cucumber picking robot
Henten, van E.J.; Schenk, E.J.J.; Willigenburg, van L.G.; Meuleman, J.; Barreiro, P.
2008-01-01
The paper presents results of research on inverse kinematics algorithms to be used in a functional model of a cucumber harvesting robot consisting of a redundant manipulator with one prismatic and six rotational joints (P6R). Within a first generic approach, the inverse kinematics problem was
Design of a Two-Step Calibration Method of Kinematic Parameters for Serial Robots
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.
Uncertainty estimation and multi sensor fusion for kinematic laser tracker measurements
Ulrich, Thomas
2013-08-01
Laser trackers are widely used to measure kinematic tasks such as tracking robot movements. Common methods to evaluate the uncertainty in the kinematic measurement include approximations specified by the manufacturers, various analytical adjustment methods and the Kalman filter. In this paper a new, real-time technique is proposed, which estimates the 4D-path (3D-position + time) uncertainty of an arbitrary path in space. Here a hybrid system estimator is applied in conjunction with the kinematic measurement model. This method can be applied to processes, which include various types of kinematic behaviour, constant velocity, variable acceleration or variable turn rates. The new approach is compared with the Kalman filter and a manufacturer's approximations. The comparison was made using data obtained by tracking an industrial robot's tool centre point with a Leica laser tracker AT901 and a Leica laser tracker LTD500. It shows that the new approach is more appropriate to analysing kinematic processes than the Kalman filter, as it reduces overshoots and decreases the estimated variance. In comparison with the manufacturer's approximations, the new approach takes account of kinematic behaviour with an improved description of the real measurement process and a reduction in estimated variance. This approach is therefore well suited to the analysis of kinematic processes with unknown changes in kinematic behaviour as well as the fusion among laser trackers.
Suspension kinematic analysis of UTeM’s FV Malaysia electric vehicle racing car
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
A general approach for optimal kinematic design of 6-DOF parallel ...
Indian Academy of Sciences (India)
Optimal kinematic design of parallel manipulators is a challenging problem. In this work, an attempt has been made to present a generalized approach of kinematic design for a 6-legged parallel manipulator, by considering only the minimally required design parameters. The same approach has been used to design a ...
Stodden, David F.; Langendorfer, Stephen J.; Fleisig, Glenn S.; Andrews, James R.
2006-01-01
The purposes of this study were to: (a) examine differences within specific kinematic variables and ball velocity associated with developmental component levels of step and trunk action (Roberton & Halverson, 1984), and (b) if the differences in kinematic variables were significantly associated with the differences in component levels, determine…
Stodden, David F.; Langendorfer, Stephen J.; Fleisig, Glenn S.; Andrews, James R.
2006-01-01
The purposes of this study were to: (a) examine the differences within 11 specific kinematic variables and an outcome measure (ball velocity) associated with component developmental levels of humerus and forearm action (Roberton & Halverson, 1984), and (b) if the differences in kinematic variables were significantly associated with the differences…
Right-handed currents at B→ K l+l− kinematic endpoint
Indian Academy of Sciences (India)
2017-10-09
Oct 9, 2017 ... The recent LHCb measured values of these observables are used to conclude an evidence of right-handed currents at the kinematic endpoint of this decay mode. As the conclusion is drawn at the maximum dilepton invariant mass square ( q 2 ) kinematic endpoint, it relies only on heavy quark symmetries ...
Scapular kinematics during manual wheelchair propulsion in able-bodied participants
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)
Background: 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
Directory of Open Access Journals (Sweden)
Keyvan Sharifmoradi
2017-07-01
Conclusion The kinematics pattern of the patient’s lower limb during gait is different. Kinematic changes are associated with a significant increase in lower limb muscle generation that can have a degenerative effect on the knee joint. So the importance of this subject should be considered by rehabilitation experts.
Scapular kinematics during manual wheelchair propulsion in able-bodied participants
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
BACKGROUND: 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
Many-particle leptonic decays of hypernuclei
International Nuclear Information System (INIS)
Lyul'ka, V.A.
1982-01-01
Leptonic decays of light hypernuclei of the type /sup A/X/sub Λ/→/sup A/-1X+p+l - +nu-bar occurring with a fairly large energy release (compared to π - meson decays) are studied. The energy and angular distributions of the decay products are calculated taking into account the strong interaction in the final state in the p-/sup A/-1X system and also the Pauli principle. The study is carried out for different sets of the kinematic variables describing decays of this type. It is shown that the effect of the final-state interaction significantly determines the energy distributions of the interacting particles and weakly affects the analogous lepton distributions in decays of this type. It is shown that it is necessary to take this effect into account in analyzing other types of hypernuclear decays with a similar energy release, namely, mesonless decays
Human Gait Feature Extraction Including a Kinematic Analysis toward Robotic Power Assistance
Directory of Open Access Journals (Sweden)
Mario I. Chacon-Murguia
2012-09-01
Full Text Available The present work proposes a method for human gait and kinematic analysis. Gait analysis consists of the determination of hip, knee and ankle positions through video analysis. Gait kinematic for the thigh and knee is then generated from this data. Evaluations of the gait analysis method indicate an acceptable performance of 86.66% for hip and knee position estimation, and comparable findings with other reported works for gait kinematic. A coordinate systems assignment is performed according to the DH algorithm and a direct kinematic model of the legs is obtained. The legs' angles obtained from the video analysis are applied to the kinematic model in order to revise the application of this model to robotic legs in a power assisted system.
Kinematics Analysis and Simulation on Transfer Robot with Six Degrees of Freedom
Directory of Open Access Journals (Sweden)
Yi Lu
2014-08-01
Full Text Available Study focuses on transfer robot with Six Degrees of Freedom, establishing kinematic equation by D-H method, analyzing forward kinematics and obtaining inverse kinematics by using method of inverse transform. Based on vector product, it develops velocity Jacobian matrix of robot. The geometric model of robot virtual prototype is established by SolidWorks software and generates parameters such as mass and moment. Kinematic simulation for robot is performed by Mathematica software and develops curve graph of displacement, velocity and accelerated speed in x, y and z direction in end executor center of robot with measurement, analysis and assessment, which provides foundation for further kinematics analysis and structure optimization as well as motion control of robot.
Kinematic CT and MR imaging of the patellofemoral joint
International Nuclear Information System (INIS)
Muhle, C.; Brossmann, J.; Heller, M.
1999-01-01
Anterior knee pain is a frequently encountered orthopedic symptom and is often associated with patellofemoral malalignment, which may cause chondromalacia of the patella. The difficulty in determining the patellar position between 0 and 30 of knee flexion with a conventional axial radiographic examination is well known. The introduction of computed tomography (CT) and magnetic resonance (MR) imaging for the diagnosis of knee joint abnormalities has enabled assessment of the patellar position in this critical range. More recently, emphasis has been placed on dynamic visualization of patellar motion to detect an abnormal tracking pattern. The important influence of the quadriceps muscle on the patellar tracking pattern is well known and has been examined during active knee extension by the use of ultrafast CT, and motion-triggered and ultrafast MR imaging. This article provides an overview of the current status of kinematic CT and MR imaging in the diagnosis of patellofemoral alignment, its clinical implications, and future directions. (orig.)
Model-based Kinematics Generation for Modular Mechatronic Toolkits
DEFF Research Database (Denmark)
Bordignon, Mirko; Schultz, Ulrik Pagh; Støy, Kasper
2011-01-01
Modular robots are mechatronic devices that enable the construction of highly versatile and flexible robotic systems whose mechanical structure can be dynamically modified. The key feature that enables this dynamic modification is the capability of the individual modules to connect to each other...... in multiple ways and thus generate a number of different mechanical systems, in contrast with the monolithic, fixed structure of conventional robots. The mechatronic flexibility, however, complicates the development of models and programming abstractions for modular robots, since manually describing...... the Modular Mechatronics Modelling Language (M3L). M3L is a domain-specific language, which can model the kinematic structure of individual robot modules and declaratively describe their possible interconnections, rather than requiring the user to enumerate them in their entirety. From this description, the M...
Comparison of robot surgery modular and total knee arthroplasty kinematics.
Yildirim, Gokce; Fernandez-Madrid, Ivan; Schwarzkopf, Ran; Walker, Peter S; Karia, Raj
2014-04-01
The kinematics of seven knee specimens were measured from 0 to 120 degrees flexion using an up-and-down crouching machine. Motion was characterized by the positions of the centers of the lateral and medial femoral condyles in the anterior-posterior direction relative to a fixed tibia. A modular unicompartmental knee, trochlea flange, and patella resurfacing (multicompartmental knee [MCK] system) were implanted using a surgeon-interactive robot system that provided accurate surface matching. The MCK was tested, followed by standard cruciate retaining (CR) and posterior stabilized (PS) knees. The motion of the MCK was close to anatomic, especially on the medial side, in contrast to the CR and PS knees that showed abnormal motion features. Such a modular knee system, accurately inserted, has the potential for close to normal function in clinical application. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
Speeding up the learning of robot kinematics through function decomposition.
Ruiz de Angulo, Vicente; Torras, Carme
2005-11-01
The main drawback of using neural networks or other example-based learning procedures to approximate the inverse kinematics (IK) of robot arms is the high number of training samples (i.e., robot movements) required to attain an acceptable precision. We propose here a trick, valid for most industrial robots, that greatly reduces the number of movements needed to learn or relearn the IK to a given accuracy. This trick consists in expressing the IK as a composition of learnable functions, each having half the dimensionality of the original mapping. Off-line and on-line training schemes to learn these component functions are also proposed. Experimental results obtained by using nearest neighbors and parameterized self-organizing map, with and without the decomposition, show that the time savings granted by the proposed scheme grow polynomially with the precision required.
Coordination of dual robot arms using kinematic redundancy
Suh, Il Hong; Shin, Kang G.
1988-01-01
A method is developed to coordinate the motion of dual robot arms carrying a solid object, where the first robot (leader) grasps one end of the object rigidly and the second robot (follower) is allowed to change its grasping position at the other end of the object along the object surface while supporting the object. It is shown that this flexible grasping is equivalent to the addition of one more degree of freedom (dof), giving the follower more maneuvering capabilities. In particular, motion commands for the follower are generated by using kinematic redundancy. To show the utility and power of the method, an example system with two PUMA 560 robots carrying a beam is analyzed.
Kinematics analysis and simulation of a new underactuated parallel robot
Directory of Open Access Journals (Sweden)
Wenxu YAN
2017-04-01
Full Text Available The number of degrees of freedom is equal to the number of the traditional robot driving motors, which causes defects such as low efficiency. To overcome that problem, based on the traditional parallel robot, a new underactuated parallel robot is presented. The structure characteristics and working principles of the underactuated parallel robot are analyzed. The forward and inverse solutions are derived by way of space analytic geometry and vector algebra. The kinematics model is established, and MATLAB is implied to verify the accuracy of forward and inverse solutions and identify the optimal work space. The simulation results show that the robot can realize the function of robot switch with three or four degrees of freedom when the number of driving motors is three, improving the efficiency of robot grasping, with the characteristics of large working space, high speed operation, high positioning accuracy, low manufacturing cost and so on, and it will have a wide range of industrial applications.
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
Strike kinematics and performance in juvenile ball pythons (Python regius).
Ryerson, William G; Tan, Weimin
2017-08-01
The rapid strike of snakes has interested researchers for decades. Although most work has focused on the strike performance of vipers, recent work has shown that other snakes outside of the Viperidae can strike with the same velocities and accelerations. However, to date all of these examples focus on performance in adult snakes. Here, we use high-speed video to measure the strike kinematics and performance of 10 juvenile (pythons, Python regius. We find that juvenile P. regius strike at levels comparable to larger snakes, but with shorter durations and over shorter distances. We conclude that the juvenile P. regius maintain performance likely through manipulation of the axial musculature and accompanying elastic tissues, and that this is a first step to understanding ontogenetic changes in behavior and a potential avenue for understanding how captivity may also impact behavior. © 2017 Wiley Periodicals, Inc.
Kinematics of radion field: a possible source of dark matter
Energy Technology Data Exchange (ETDEWEB)
Chakraborty, Sumanta [IUCAA, Pune (India); SenGupta, Soumitra [Indian Association for the Cultivation of Science, Department of Theoretical Physics, Kolkata (India)
2016-12-15
The discrepancy between observed virial and baryonic mass in galaxy clusters have lead to the missing mass problem. To resolve this, a new, non-baryonic matter field, known as dark matter, has been invoked. However, till date no possible constituents of the dark matter components are known. This has led to various models, by modifying gravity at large distances to explain the missing mass problem. The modification to gravity appears very naturally when effective field theory on a lower-dimensional manifold, embedded in a higher-dimensional spacetime is considered. It has been shown that in a scenario with two lower-dimensional manifolds separated by a finite distance is capable to address the missing mass problem, which in turn determines the kinematics of the brane separation. Consequences for galactic rotation curves are also described. (orig.)
On the General Analytical Solution of the Kinematic Cosserat Equations
Michels, Dominik L.
2016-09-01
Based on a Lie symmetry analysis, we construct a closed form solution to the kinematic part of the (partial differential) Cosserat equations describing the mechanical behavior of elastic rods. The solution depends on two arbitrary analytical vector functions and is analytical everywhere except a certain domain of the independent variables in which one of the arbitrary vector functions satisfies a simple explicitly given algebraic relation. As our main theoretical result, in addition to the construction of the solution, we proof its generality. Based on this observation, a hybrid semi-analytical solver for highly viscous two-way coupled fluid-rod problems is developed which allows for the interactive high-fidelity simulations of flagellated microswimmers as a result of a substantial reduction of the numerical stiffness.
Studies of kinematic elements in two multicenter sunspot groups
International Nuclear Information System (INIS)
Korobova, Z.B.
1983-01-01
Some features of kinematic elements (KE) in two multicenter sunspot groups were studied using Tashkent full-disc white light heliograms. KE and morphological elements do not reveal any relationship. A KE coincides with a unipolar or multipolar spot or with part of a spot. It may also contain an extended stream including several spots. Relation of KE to large-scale photospheric magnetic fields is less clear. The line of polarity reversal is, in most cases, the deviding line between two adjacent KE. At the same time, a KE can contain spots of both polarities. Sunspot trajectories in the leading polarity regions show the best similarity. Interactions of KE are greatly influenced by the meridional drift. (author)
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.
Geometrical and kinematical characterization of parallax-free world models
International Nuclear Information System (INIS)
Hasse, W.; Perlick, V.
1988-01-01
An arbitrary general relativistic world model, i.e., a pseudo-Riemannian manifold along with a timelike vector field V, is considered. Such a kinematical world model is called ''parallax-free'' iff the angle under which any two observers (i.e., integral curves of V) are seen by any third observer remains constant in the course of time. It is shown that a model is parallax-free iff V is proportional to some conformal Killing field. In this case V, especially, has to be shear-free. Furthermore a relationship between parallaxes and red shift is presented and a reference is made to considerations concerning the visibility of cosmic rotation
Mandibular kinematics after orthognathic surgical treatment a pilot study.
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.