WorldWideScience

Sample records for wall motion analysis

  1. Analysis of intracranial aneurysm wall motion and its effects on hemodynamic patterns

    Science.gov (United States)

    Oubel, Estanislao; De Craene, Mathieu; Putman, Christopher M.; Cebral, Juan R.; Frangi, Alejandro F.

    2007-03-01

    Hemodynamics, and in particular Wall Shear Stress (WSS), is thought to play a critical role in the progression and rupture of intracranial aneurysms. Wall motion is related to local biomechanical properties of the aneurysm, which in turn are associated with the amount of damage undergone by the tissue. The underlying hypothesis in this work is that injured regions show differential motion with respect to normal ones, allowing a connection between local wall biomechanics and a potential mechanism of wall injury such as elevated WSS. In a previous work, a novel method was presented combining wall motion estimation using image registration techniques with Computational Fluid Dynamics (CFD) simulations in order to provide realistic intra-aneurysmal flow patterns. It was shown that, when compared to compliant vessels, rigid models tend to overestimate WSS and produce smaller areas of elevated WSS and force concentration, being the observed differences related to the magnitude of the displacements. This work aims to further study the relationships between wall motion, flow patterns and risk of rupture in aneurysms. To this end, four studies containing both 3DRA and DSA studies were analyzed, and an improved version of the method developed previously was applied to cases showing wall motion. A quantification and analysis of the displacement fields and their relationships to flow patterns are presented. This relationship may play an important role in understanding interaction mechanisms between hemodynamics, wall biomechanics, and the effect on aneurysm evolution mechanisms.

  2. Rapid estimation of left ventricular ejection fraction in acute myocardial infarction by echocardiographic wall motion analysis

    DEFF Research Database (Denmark)

    Berning, J; Rokkedal Nielsen, J; Launbjerg, J

    1992-01-01

    Echocardiographic estimates of left ventricular ejection fraction (ECHO-LVEF) in acute myocardial infarction (AMI) were obtained by a new approach, using visual analysis of left ventricular wall motion in a nine-segment model. The method was validated in 41 patients using radionuclide...

  3. Automated classification of wall motion abnormalities by principal component analysis of endocardial shape motion patterns in echocardiograms

    Science.gov (United States)

    Bosch, Johan G.; Nijland, Francisca; Mitchell, Steven C.; Lelieveldt, Boudewijn P. F.; Kamp, Otto; Sonka, Milan; Reiber, Johan H. C.

    2003-05-01

    Principal Component Analysis of sets of temporal shape sequences renders eigenvariations of shape/motion, including typical normal and pathological endocardial contraction patterns. A previously developed Active Appearance Model for time sequences (AAMM) was employed to derive AAMM shape coefficients (ASCs) and we hypothesized these would allow classification of wall motion abnormalities (WMA). A set of stress echocardiograms (single-beat 4-chamber and 2-chamber sequences with expert-verified endocardial contours) of 129 infarct patients was split randomly into training (n=65) and testing (n=64) sets. AAMMs were generated from the training set and for all sequences ASCs were extracted and statistically related to regional/global Visual Wall Motion Scoring (VWMS) and clinical infarct severity and volumetric parameters. Linear regression showed clear correlations between ASCs and VWMS. Infarct severity measures correlated poorly to both ASCs and VWMS. Discriminant analysis showed good prediction from low #ASCs of both segmental (85% correctness) and global WMA (90% correctness). Volumetric parameters correlated poorly to regional VWMS. Conclusions: 1)ASCs show promising accuracy for automated WMA classification. 2)VWMS and endocardial border motion are closely related; with accurate automated border detection, automated WMA classification should be feasible. 3)ASC shape analysis allows contour set evaluation by direct comparison to clinical parameters.

  4. Analysis of Human's Motions Based on Local Mean Decomposition in Through-wall Radar Detection

    Science.gov (United States)

    Lu, Qi; Liu, Cai; Zeng, Zhaofa; Li, Jing; Zhang, Xuebing

    2016-04-01

    Observation of human motions through a wall is an important issue in security applications and search-and rescue. Radar has advantages in looking through walls where other sensors give low performance or cannot be used at all. Ultrawideband (UWB) radar has high spatial resolution as a result of employment of ultranarrow pulses. It has abilities to distinguish the closely positioned targets and provide time-lapse information of targets. Moreover, the UWB radar shows good performance in wall penetration when the inherently short pulses spread their energy over a broad frequency range. Human's motions show periodic features including respiration, swing arms and legs, fluctuations of the torso. Detection of human targets is based on the fact that there is always periodic motion due to breathing or other body movements like walking. The radar can gain the reflections from each human body parts and add the reflections at each time sample. The periodic movements will cause micro-Doppler modulation in the reflected radar signals. Time-frequency analysis methods are consider as the effective tools to analysis and extract micro-Doppler effects caused by the periodic movements in the reflected radar signal, such as short-time Fourier transform (STFT), wavelet transform (WT), and Hilbert-Huang transform (HHT).The local mean decomposition (LMD), initially developed by Smith (2005), is to decomposed amplitude and frequency modulated signals into a small set of product functions (PFs), each of which is the product of an envelope signal and a frequency modulated signal from which a time-vary instantaneous phase and instantaneous frequency can be derived. As bypassing the Hilbert transform, the LMD has no demodulation error coming from window effect and involves no negative frequency without physical sense. Also, the instantaneous attributes obtained by LMD are more stable and precise than those obtained by the empirical mode decomposition (EMD) because LMD uses smoothed local

  5. Heart wall motion analysis by dynamic 3D strain rate imaging from tissue Doppler echocardiography

    Science.gov (United States)

    Hastenteufel, Mark; Wolf, Ivo; de Simone, Raffaele; Mottl-Link, Sibylle; Meinzer, Hans-Peter

    2002-04-01

    The knowledge about the complex three-dimensional (3D) heart wall motion pattern, particular in the left ventricle, provides valuable information about potential malfunctions, e.g., myocardial ischemia. Nowadays, echocardiography (cardiac ultrasound) is the predominant technique for evaluation of cardiac function. Beside morphology, tissue velocities can be obtained by Doppler techniques (tissue Doppler imaging, TDI). Strain rate imaging (SRI) is a new technique to diagnose heart vitality. It provides information about the contraction ability of the myocardium. Two-dimensional color Doppler echocardiography is still the most important clinical method for estimation of morphology and function. Two-dimensional methods leads to a lack of information due to the three-dimensional overall nature of the heart movement. Due to this complex three-dimensional motion pattern of the heart, the knowledge about velocity and strain rate distribution over the whole ventricle can provide more valuable diagnostic information about motion disorders. For the assessment of intracardiac blood flow three-dimensional color Doppler has already shown its clinical utility. We have developed methods to produce strain rate images by means of 3D tissue Doppler echocardiography. The tissue Doppler and strain rate images can be visualized and quantified by different methods. The methods are integrated into an interactively usable software environment, making them available in clinical everyday life. Our software provides the physician with a valuable tool for diagnosis of heart wall motion.

  6. Micromagnetic analysis of current-driven domain wall motion of multi-bit in a nanowire with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Hiroshi; Takahashi, Kouta; Komine, Takashi; Sugita, Ryuji, E-mail: komine@mx.ibaraki.ac.j [4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Ibaraki University (Japan)

    2010-01-01

    The current-driven domain wall motion of a multi-bit in a magnetic nanowire with perpendicular magnetic anisotropy has been analyzed by performing a micromagnetic simulation. The multi-bit motion is determined by the applied current density and the non-adiabatic spin torque parameters, which is similar to the current-driven domain wall motion of the single wall. Consequently, it was found that are two modes in the multi-bit motion: (a) the bit length remains constant and (b) the bit length varies or the bit vanishes in the nanowire. It was found that these modes of the multi-bit motion can be classified by the critical current density or Walker breakdown for the single wall motion in a magnetic nanowire with perpendicular magnetic anisotropy.

  7. Identification and Assessment of Paradoxical Ventricular Wall Motion Using ECG Gated Blood Pool Scan - Comparison of cine Loop , Phase Analysis and Paradox Image -

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Tae; Kim, Gwang Weon; Lee, Kyu Bo; Chung, Byung Chun; Whang, Kee Suk; Chae, Sung Chul; Paek, Wee Hyun; Cheon, Jae Eun [Kyungpook National University School of Medicine, Daegu (Korea, Republic of); Lee, Hyong Woo; Chung, Jin Hong [Yeongnam National University College of Medicine, Daegu (Korea, Republic of)

    1990-07-15

    Sixty-four patients with paradoxical ventricular wall motion noticed both in angiocardiography or 2-dimensional echocardiography were assessed by ECG gated blood pool scan (GBPS). Endless cine loop image, phase and amplitude images and paradox image obtained by visual inspection of each cardiac beat or Fourier transformation of acquired raw data were investigated to determine the incremental value of GBPS with these processing methods for identification of paradoxical ventricular wall motion. The results were as follows:1) Paradoxical wall motions were observed on interventricular septum in 34 cases, left ventricular free wall in 26 and right ventricular wall in 24. Underlying heart diseases were is chemic (23 cases) valvular(9), congenital heart disease (12), cardiomyopathy (5), pericardial effusion(5), post cardiac surgery(3), corpulmonale (2), endocarditis (l) and right ventricular tumor(l). 2) Left ventricular ejection fractions of patients with paradoxical left ventricular wall motion were significantly lower than those with paradoxical septal motion (p <0.005). 3) The sensitivity of each processing methods for detecting paradoxical wall motion was 76.9% by phase analysis, 74.6% by endless cine loop mapping and 68.4% by paradox image manipulation respectively. Paradoxial motions visualized only in phase, paradox or both images were appeared as hypokinesia or akinesia in cine loop image. 4) All events could be identified by at least one of above three processing methods, however only 34 cases (48.4%) showed the paradoxical motions in all of the three images. By these findings, we concluded that simultaneous inspection of all above three processing methods-endless cine loop, phase analysis and paradox image is necessary for accurate identification and assessment of paradoxical ventricular wall motion when performing GBPS.

  8. Analysis of Peristaltic Motion of a Nanofluid with Wall Shear Stress, Microrotation, and Thermal Radiation Effects

    Directory of Open Access Journals (Sweden)

    C. Dhanapal

    2016-01-01

    Full Text Available This paper analyzes the peristaltic flow of an incompressible micropolar nanofluid in a tapered asymmetric channel in the presence of thermal radiation and heat sources parameters. The rotation of the nanoparticles is incorporated in the flow model. The equations governing the nanofluid flow are modeled and exact solutions are managed under long wavelength and flow Reynolds number and long wavelength approximations. Explicit expressions of axial velocity, stream function, microrotation, nanoparticle temperature, and concentration have been derived. The phenomena of shear stress and trapping have also been discussed. Finally, the influences of various parameters of interest on flow variables have been discussed numerically and explained graphically. Besides, the results obtained in this paper will be helpful to those who are working on the development of various realms like fluid mechanics, the rotation, Brownian motion, thermophoresis, coupling number, micropolar parameter, and the nondimensional geometry parameters.

  9. Analysis of Peristaltic Motion of a Nanofluid with Wall Shear Stress, Microrotation, and Thermal Radiation Effects

    Science.gov (United States)

    Dhanapal, C.; Kamalakkannan, J.; Prakash, J.

    2016-01-01

    This paper analyzes the peristaltic flow of an incompressible micropolar nanofluid in a tapered asymmetric channel in the presence of thermal radiation and heat sources parameters. The rotation of the nanoparticles is incorporated in the flow model. The equations governing the nanofluid flow are modeled and exact solutions are managed under long wavelength and flow Reynolds number and long wavelength approximations. Explicit expressions of axial velocity, stream function, microrotation, nanoparticle temperature, and concentration have been derived. The phenomena of shear stress and trapping have also been discussed. Finally, the influences of various parameters of interest on flow variables have been discussed numerically and explained graphically. Besides, the results obtained in this paper will be helpful to those who are working on the development of various realms like fluid mechanics, the rotation, Brownian motion, thermophoresis, coupling number, micropolar parameter, and the nondimensional geometry parameters. PMID:27688703

  10. Power optimization for domain wall motion in ferromagnetic nanowires

    Science.gov (United States)

    Tretiakov, O. A.; Liu, Y.; Abanov, Ar.

    2011-04-01

    The current mediated domain-wall dynamics in a thin ferromagnetic wire is investigated. We derive the effective equations of motion of the domain wall. They are used to study the possibility to optimize the power supplied by electric current for the motion of domain walls in a nanowire. We show that a certain resonant time-dependent current moving a domain wall can significantly reduce the Joule heating in the wire, and thus it can lead to a novel proposal for the most energy efficient memory devices. We discuss how Gilbert damping, nonadiabatic spin transfer torque, and the presence of Dzyaloshinskii-Moriya interaction can effect this power optimization.

  11. Power optimization for domain wall motion in ferromagnetic nanowires

    OpenAIRE

    Tretiakov, Oleg A.; Liu, Y.; Abanov, Ar.

    2010-01-01

    The current mediated domain-wall dynamics in a thin ferromagnetic wire is investigated. We derive the effective equations of motion of the domain wall. They are used to study the possibility to optimize the power supplied by electric current for the motion of domain walls in a nanowire. We show that a certain resonant time-dependent current moving a domain wall can significantly reduce the Joule heating in the wire, and thus it can lead to a novel proposal for the most energy efficient memory...

  12. Options for assessing and measuring chest wall motion.

    Science.gov (United States)

    Seddon, Paul

    2015-01-01

    Assessing chest wall motion is a basic and vital component in managing the child with respiratory problems, whether these are due to pathology in the lungs, airways, chest wall or muscles. Since the 1960s, clinical assessment has been supplemented with an ever-growing range of technological options for measuring chest wall motion, each with unique advantages and disadvantages. Measurements of chest wall motion can be used to: (1) Assess respiratory airflow and volume change, as a non-invasive alternative to measurement at the airway opening, (2) Monitor breathing over long periods of time, to identify apnoea and other types of sleep-disordered breathing, (3)Identify and quantify patterns of abnormal chest wall movement, whether between ribcage and abdominal components (thoracoabdominal asynchrony) or between different regions of the ribcage (eg in scoliosis and pectus excavatum). Measuring chest wall motion allows us to do things which simply cannot be done by more mainstream respiratory function techniques measuring flow at the airway opening: it allows respiratory airflow to be measured when it would otherwise be impossible, and it tells us how the different parts of the chest wall (eg ribcage vs abdomen, right vs left) are moving in order to generate that airflow. The basis of the different techniques available to assess and measure chest wall motion will be reviewed and compared, and their relevance to paediatric respiratory practice assessed.

  13. Motional Effect on Wall Shear Stresses

    DEFF Research Database (Denmark)

    Kock, Samuel Alberg; Torben Fründ, Ernst; Yong Kim, Won

    Atherosclerosis is the leading cause of death and severe disability. Wall Shear Stress (WSS), the stress exerted on vessel walls by the flowing blood is a key factor in the development of atherosclerosis. Computational Fluid Dynamics (CFD) is widely used for WSS estimations. Most CFD simulations...... are based on static models to ease computational burden leading to inaccurate estimations. The aim of this work was to estimate the effect of vessel wall deformations (expansion and bending) on WSS levels....

  14. Induced motion of domain walls in multiferroics with quadratic interaction

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimchuk, Victor S., E-mail: viktor.gera@gmail.com [National Technical University of Ukraine “Kyiv Polytechnic Institute”, Peremohy Avenue 37, 03056 Kiev (Ukraine); Shitov, Anatoliy A., E-mail: shitov@mail.ru [Donbass National Academy of Civil Engineering, Derzhavina Street 2, 86123 Makeevka, Donetsk Region (Ukraine)

    2013-10-15

    We theoretically study the dynamics of 180-degree domain wall of the ab-type in magnetic materials with quadratic magnetoelectric interaction in external alternating magnetic and electric fields. The features of the oscillatory and translational motions of the domain walls and stripe structures depending on the parameters of external fields and characteristics of the multiferroics are discussed. The possibility of the domain walls drift in a purely electric field is established. - Highlights: • We study DW and stripe DS in multiferroics with quadratic magnetoelectric interaction. • We build up the theory of oscillatory and translational (drift) DW and DS motion. • DW motion can be caused by crossed alternating electric and magnetic fields. • DW motion can be caused by alternating “pure” electric field. • DW drift velocity is formed by the AFM and Dzyaloshinskii interaction terms.

  15. Time-periodic N\\'eel wall motions

    CERN Document Server

    Huber, Alexander

    2010-01-01

    In thin ferromagnetic films, the predominance of the magnetic shape anisotropy leads to in-plane magnetizations. The simplest domain wall in this geometry is the one-dimensional Neel wall that connects two magnetizations of opposite sign by a planar 180 degree rotation. In this paper, we perturb the static Neel wall profile in order to construct time-periodic Neel wall motions governed by to the Landau-Lifshitz-Gilbert equation. Our construction works within a certain parameter regime and requires the restriction to external magnetic fields with small amplitudes and suitable time averages.

  16. Intraventricular flow alterations due to dyssynchronous wall motion

    Science.gov (United States)

    Pope, Audrey M.; Lai, Hong Kuan; Samaee, Milad; Santhanakrishnan, Arvind

    2015-11-01

    Roughly 30% of patients with systolic heart failure suffer from left ventricular dyssynchrony (LVD), in which mechanical discoordination of the ventricle walls leads to poor hemodynamics and suboptimal cardiac function. There is currently no clear mechanistic understanding of how abnormalities in septal-lateral (SL) wall motion affects left ventricle (LV) function, which is needed to improve the treatment of LVD using cardiac resynchronization therapy. We use an experimental flow phantom with an LV physical model to study mechanistic effects of SL wall motion delay on LV function. To simulate mechanical LVD, two rigid shafts were coupled to two segments (apical and mid sections) along the septal wall of the LV model. Flow through the LV model was driven using a piston pump, and stepper motors coupled to the above shafts were used to locally perturb the septal wall segments relative to the pump motion. 2D PIV was used to examine the intraventricular flow through the LV physical model. Alterations to SL delay results in a reduction in the kinetic energy (KE) of the flow field compared to synchronous SL motion. The effect of varying SL motion delay from 0% (synchronous) to 100% (out-of-phase) on KE and viscous dissipation will be presented. This research was supported by the Oklahoma Center for Advancement of Science and Technology (HR14-022).

  17. Rising motion of a bubble layer near a vertical wall

    Science.gov (United States)

    Dabiri, Sadegh; Bhuvankar, Pramod

    2015-11-01

    Bubbly flows in vertical pipes and channels form a wall-peak distribution of bubbles under certain conditions. The dynamics of the bubbles near the wall is different than in an unbounded liquid. Here we report the rising motion of bubbles in a liquid near a vertical wall. In a simulation of a bubbly flow in a periodic domain with a vertical wall on one side, an average pressure gradient is applied to the domain that balances the weight of the liquid phase. The upward flow is created by the rising motion of the bubbles. The bubbles are kept near the wall by the lateral lift force acting on them as a result of rising in a shear flow which is in turn generated by rising motion of bubbles. The rise velocity of the bubbles on the wall and the average rise velocity of the liquid depend on three dimensionless parameters, Archimedes number, Eotvos number, and the average volume fraction of bubbles near the wall. In the limit of small Eo, bubbles are nearly spherical and the dependency on Eo becomes negligible. In this limit, the scaling of the liquid Reynolds number with Archimedes number and the void fraction is presented.

  18. Submicrometric 2D ratchet effect in magnetic domain wall motion

    Energy Technology Data Exchange (ETDEWEB)

    Castán-Guerrero, C., E-mail: ccastan@unizar.es [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Herrero-Albillos, J. [Fundación ARAID, E-50004 Zaragoza (Spain); Centro Universitario de la Defensa, E-50090 Zaragoza (Spain); Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Sesé, J. [Instituto de Nanociencia de Aragón, Laboratorio de Microscopías Avanzadas, Universidad de Zaragoza, E-50018 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Bartolomé, J.; Bartolomé, F. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Hierro-Rodriguez, A.; Valdés-Bango, F.; Martín, J.I.; Alameda, J.M. [Dpto. Física, Universidad de Oviedo, Asturias (Spain); CINN (CSIC – Universidad de Oviedo – Principado de Asturias), Asturias (Spain); García, L.M. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain)

    2014-12-15

    Strips containing arrays of submicrometric triangular antidots with a 2D square periodicity have been fabricated by electron beam lithography. A clear ratchet effect of 180° domain wall motion under a varying applied field parallel to the walls has been observed. The direction is determined by the direction of the triangle vertices. In contrast, no ratchet effect is observed when the antidot array is constituted by symmetric rhomb-shaped antidots.

  19. Scaling analysis on filtered near wall turbulence

    Science.gov (United States)

    Mohan, Prakash; Moser, Robert

    2016-11-01

    Large Eddy Simulations (LES) directly represent larger scale turbulent motions and model the effects of small scale motions. However in the near wall region the large dynamically important eddies scale in viscous wall units, which makes resolving them in a high Reynolds number LES very expensive. This motivates the use of wall-modeled LES, in which these near-wall eddies are modeled. To aid in the development of new wall models, we pursue an asymptotic analysis of the filtered Navier-Stokes equations, in the limit in which the horizontal filter scale is large compared to the thickness of the wall layer. It will be shown that in this limit the filtered velocities u and subgrid stresses τ in the near-wall layer are determined to zeroth order by filtered velocities at the boundary of the wall layer. Further the asymptotics suggest that there is a scaled universal velocity profile f and subgrid stress profile g in the near-wall region. The validity of this result will be tested and the profiles f and g will be evaluated through analysis of DNS data from channel flow at Reτ = 5200 .

  20. Magnetic domain wall motion triggered by electric field

    Energy Technology Data Exchange (ETDEWEB)

    Pyatakov, A P; Sergeev, A S; Sechin, D A; Meshkov, G A; Nikolaeva, E P; Nikolaev, A V; Logginov, A S [Physics Department, M.V. Lomonosov Moscow State University, Leninskie gory, Moscow, 119296 (Russian Federation); Zvezdin, A K, E-mail: pyatakov@phys.msu.r [A.M. Prokhorov General Physics Institute, 38, Vavilova st., Moscow, 119991 (Russian Federation)

    2010-01-01

    We propose the new approach to the problem of electrically controlled magnetic state: the electric field driven domain wall motion. The effect is demonstrated in iron garnet films in ambient conditions. The theoretical model based on inhomogenous magnetoelectric interaction provides with the necessary criteria of the effect and the way to maximize it.

  1. Linear motion feed through with thin wall rubber sealing element

    Science.gov (United States)

    Mikhailov, V. P.; Deulin, E. A.

    2017-07-01

    The patented linear motion feedthrough is based on elastic thin rubber walls usage being reinforced with analeptic string fixed in the middle part of the walls. The pneumatic or hydro actuators create linear movement of stock. The length of this movement is two times more the rubber wall length. This flexible wall is a sealing element of feedthrough. The main advantage of device is negligible resistance force that is less then mentioned one in sealing bellows that leads to positioning error decreasing. Nevertheless, the thin wall rubber sealing element (TRE) of the feedthrough is the main unreliable element that was the reason of this element longevity research. The theory and experimental results help to create equation for TRE longevity calculation under vacuum or extra high pressure difference action. The equation was used for TRE longevity determination for hydraulic or vacuum equipment realization also as it helps for gas flow being leaking through the cracks in thin walls of rubber sealing element of linear motion feedthrough calculation.

  2. Experimental Study on Current-Driven Domain Wall Motion

    Science.gov (United States)

    Ono, T.; Yamaguchi, A.; Tanigawa, H.; Yano, K.; Kasai, S.

    2006-06-01

    Current-driven domain wall (DW) motion for a well-defined single DW in a micro-fabricated magnetic wire with submicron width was investigated by real-space observation with magnetic force microscopy. Magnetic force microscopy visualizes that a single DW introduced in a wire is displaced back and forth by positive and negative pulsed-current, respectively. Effect of the Joule heating, reduction of the threshold current density by shape control, and magnetic ratchet effect are also presented.

  3. Wellens' syndrome with segmental wall-motion abnormalities

    OpenAIRE

    Bugan, Baris; Celik,Turgay; Celik,Murat; Dermikoh,Sait; Iyisoy,Atila; Serdar ,Firtina

    2010-01-01

    Turgay Celik1, Baris Bugan1, Serdar Firtina1, Murat Celik2, Sait Demirkol1, Atila Iyisoy11Gulhane Military Medical Academy, Department of Cardiology, Ankara, Turkey; 2Van Army District Hospital, Department of Cardiology, Van, TurkeyAbstract: Wellens' syndrome is a pattern of electrocardiographic T-wave changes associated with critical, proximal left anterior descending (LAD) artery stenosis. We herein report 2 cases of Wellens' syndrome with segmental wall-motion abnormalities...

  4. Motion analysis report

    Science.gov (United States)

    Badler, N. I.

    1985-01-01

    Human motion analysis is the task of converting actual human movements into computer readable data. Such movement information may be obtained though active or passive sensing methods. Active methods include physical measuring devices such as goniometers on joints of the body, force plates, and manually operated sensors such as a Cybex dynamometer. Passive sensing de-couples the position measuring device from actual human contact. Passive sensors include Selspot scanning systems (since there is no mechanical connection between the subject's attached LEDs and the infrared sensing cameras), sonic (spark-based) three-dimensional digitizers, Polhemus six-dimensional tracking systems, and image processing systems based on multiple views and photogrammetric calculations.

  5. Quantitative Evaluation of Left Ventricular Wall Motion in Patient with Coronary Artery Bypass Grafting Using Magnetic Resonance Tagging Technique

    Science.gov (United States)

    Inaba, Tadashi; Nakano, Takahiro; Tsutsumi, Masakazu; Kawasaki, Shingo; Kinosada, Yasutomi; Tokuda, Masataka

    Left ventricular wall motions during systole were investigated from a mechanical perspective by using a magnetic resonance tagging technique. Subjects were 7 patients with coronary artery bypass grafting (CABG). First, by analyzing strain in the left ventricular wall, cardiac contractility was evaluated in the patients with CABG. Next, by calculating displacement in the myocardial wall, paradoxical movements following CABG were quantitatively evaluated. Strain analysis showed local decreases in circumferential strain in 4 of 7 subjects. The results of displacement analysis clarified that following CABG, the degree of radial displacement was small in the septal wall and large in the lateral wall, and circumferential displacement towards the septal wall occurred in the anterior and posterior walls. Since this behavior was seen in both reduced and normal cardiac contractility groups, paradoxical movements in the present patients were not caused by reduced cardiac contractility, but rather by rigid-body motion of the entire heart.

  6. Simulation and signal processing of through wall UWB radar for human being's periodic motions detection

    Science.gov (United States)

    Li, Jing; Liu, Fengshan; Xu, Penglong; Zeng, Zhaofa

    2013-05-01

    The human's Micro-Doppler signatures resulting from breathing, arm, foot and other periodic motion can provide valuable information about the structure of the moving parts and may be used for identification and classification purposes. In this paper, we carry out simulate with FDTD method and through wall experiment with UWB radar for human being's periodic motion detection. In addition, Advancements signal processing methods are presented to classify and to extract the human's periodic motion characteristic information, such as Micro-Doppler shift and motion frequency. Firstly, we apply the Principal Component Analysis (PCA) with singular value decomposition (SVD) to denoise and extract the human motion signal. Then, we present the results base on the Hilbert-Huang transform (HHT) and the S transform to classify and to identify the human's micro-Doppler shift characteristics. The results demonstrate that the combination of UWB radar and various processing methods has potential to detect human's Doppler signatures effectively.

  7. Current-induced domain wall motion in nanoscale ferromagnetic elements

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, G [Laboratoire de Physique des Solides, CNRS, Universite Paris-sud 11, 91405 Orsay Cedex (France); Boulle, O [SPINTEC, CEA/CNRS/UJF/GINP, INAC, 38054 Grenoble Cedex 9 (France); Klaeui, M, E-mail: Klaeui@uni-mainz.de [SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Laboratory of Nanomagnetism and Spin Dynamics, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

    2011-09-28

    We review the details of domain wall (DW) propagation due to spin-polarized currents that could potentially be used in magnetic data storage devices based on domains and DWs. We discuss briefly the basics of the underlying spin torque effect and show how the two torques arising from the interaction between the spin-polarized charge carriers and the magnetization lead to complex dynamics of a spin texture such as a DW. By direct imaging we show how confined DWs in nanowires can be displaced using currents in in-plane soft-magnetic materials, and that when using short pulses, fast velocities can be attained. For high-anisotropy out-of-plane magnetized wires with narrow DWs we present approaches to deducing the torque terms and show that in these materials potentially more efficient domain wall motion could be achieved.

  8. Rashba Torque Driven Domain Wall Motion in Magnetic Helices.

    Science.gov (United States)

    Pylypovskyi, Oleksandr V; Sheka, Denis D; Kravchuk, Volodymyr P; Yershov, Kostiantyn V; Makarov, Denys; Gaididei, Yuri

    2016-01-01

    Manipulation of the domain wall propagation in magnetic wires is a key practical task for a number of devices including racetrack memory and magnetic logic. Recently, curvilinear effects emerged as an efficient mean to impact substantially the statics and dynamics of magnetic textures. Here, we demonstrate that the curvilinear form of the exchange interaction of a magnetic helix results in an effective anisotropy term and Dzyaloshinskii-Moriya interaction with a complete set of Lifshitz invariants for a one-dimensional system. In contrast to their planar counterparts, the geometrically induced modifications of the static magnetic texture of the domain walls in magnetic helices offer unconventional means to control the wall dynamics relying on spin-orbit Rashba torque. The chiral symmetry breaking due to the Dzyaloshinskii-Moriya interaction leads to the opposite directions of the domain wall motion in left- or right-handed helices. Furthermore, for the magnetic helices, the emergent effective anisotropy term and Dzyaloshinskii-Moriya interaction can be attributed to the clear geometrical parameters like curvature and torsion offering intuitive understanding of the complex curvilinear effects in magnetism.

  9. Effects of impurity transport and melt layer motion to the tungsten wall erosion during anomaly events

    Energy Technology Data Exchange (ETDEWEB)

    Ibano, K., E-mail: kibano@eei.eng.osaka-u.ac.jp; Tsutsui, T.; Lang, T.L.; Togo, S.; Ogawa, Y.

    2015-08-15

    Developing designs of future fusion devices, safety and soundness of the rector at anomaly events must be ensured. A computational approach is being taken by developing a homegrown integrated reactor simulation code and analyzing a loss-of-cooling-gas-puff accident (LCGA). This code currently includes simple plasma, edge, and wall models. In this study, models for the tungsten transport and melt layer motion was added and used for the analysis. It was found that this accident results significant erosion of the wall while impurities from the wall would contribute the radiation cooling for the intense heat flux. However, these effects strongly depend on an uncertain parameter of the tungsten transport as well as the tungsten melt layer motion. Thus, parametric survey for these uncertain quantities were taken and discussed.

  10. Simultaneous effects of slip and wall properties on MHD peristaltic motion of nanofluid with Joule heating

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, T. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, King Abdulaziz University, P.O. Box 80257, Jeddah 21589 (Saudi Arabia); Nisar, Z. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Ahmad, B. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, King Abdulaziz University, P.O. Box 80257, Jeddah 21589 (Saudi Arabia); Yasmin, H., E-mail: qau2011@gmail.com [Department of Mathematics, COMSATS Institute of Information Technology, G.T. Road, Wah Cantt 47040 (Pakistan)

    2015-12-01

    This paper is devoted to the magnetohydrodynamic (MHD) peristaltic transport of nanofluid in a channel with wall properties. Flow analysis is addressed in the presence of viscous dissipation, partial slip and Joule heating effects. Mathematical modelling also includes the salient features of Brownian motion and thermophoresis. Both analytic and numerical solutions are provided. Comparison between the solutions is shown in a very good agreement. Attention is focused to the Brownian motion parameter, thermophoresis parameter, Hartman number, Eckert number and Prandtl number. Influences of various parameters on skin friction coefficient, Nusselt and Sherwood numbers are also investigated. It is found that both the temperature and nanoparticles concentration are increasing functions of Brownian motion and thermophoresis parameters. - Highlights: • Temperature rises when Brownian motion and thermophoresis effects intensify. • Temperature profile increases when thermal slip parameter increases. • Concentration field is a decreasing function of concentration slip parameter. • Temperature decreases whereas concentration increases for Hartman number.

  11. Current-induced domain wall motion in ferromagnetic semiconductors

    Science.gov (United States)

    Ohno, Hideo

    2007-03-01

    Low magnetization (˜0.05 T) and high spin-polarization in ferromagnetism of transition metal-doped GaAs allow us to explore a number of spin-dependent phenomena not readily accessible in metal ferromagnets. Spin-polarized current induced domain wall (DW) motion in (Ga,Mn)As [1, 2] reveals rich physics resulting from the interaction between spin-polarized electrons and localized spins inside a magnetic DW. By using a 30 nm thick (Ga,Mn)As layer (xMn = 0.045) with perpendicular magnetic anisotropy, we have measured by magneto-optical Kerr microscopy a wide range of velocity-current density curves in the sample temperature range of 97 -- 107 K. Two regimes are found in the current density dependence of the DW velocity. At high-current densities (> 2 x 10^5 A/cm^2), the domain wall velocity is approximately a linear function of the current density above a threshold current density. This result will be compared to the recent theories of DW motion. At low-current densities, the functional form of the velocity-current curves follow an empirical scaling law, obtained by modifying the one for magnetic-field induced creep. This shows that current-induced DW creep is present. We have also determined the intrinsic resistance of the DW in a similar configuration [3]. *M. Yamanouchi, D. Chiba, F. Matsukura, and H. Ohno, Nature 428, 539 (2004). *M. Yamanouchi, D. Chiba, F. Matsukura, T. Dietl and H. Ohno, Phys. Rev. Lett. 96, 096601 (2006). *D. Chiba, M. Yamanouchi, F. Matsukura, T. Dietl, and H. Ohno, Phys. Rev. Lett. 96, 096602 (2006).

  12. Controlled motion of domain walls in submicron amorphous wires

    Directory of Open Access Journals (Sweden)

    Mihai Ţibu

    2016-05-01

    Full Text Available Results on the control of the domain wall displacement in cylindrical Fe77.5Si7.5B15 amorphous glass-coated submicron wires prepared by rapid quenching from the melt are reported. The control methods have relied on conical notches with various depths, up to a few tens of nm, made in the glass coating and in the metallic nucleus using a focused ion beam (FIB system, and on the use of small nucleation coils at one of the sample ends in order to apply magnetic field pulses aimed to enhance the nucleation of reverse domains. The notch-based method is used for the first time in the case of cylindrical ultrathin wires. The results show that the most efficient technique of controlling the domain wall motion in this type of samples is the simultaneous use of notches and nucleation coils. Their effect depends on wire diameter, notch depth, its position on the wire length, and characteristics of the applied pulse.

  13. A method to quantitate regional wall motion in left ventriculography using Hildreth algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Terashima, Mikio [Hyogo Red Cross Blood Center (Japan); Naito, Hiroaki; Sato, Yoshinobu; Tamura, Shinichi; Kurosawa, Tsutomu

    1998-06-01

    Quantitative measurement of ventricular wall motion is indispensable for objective evaluation of cardiac function associated with coronary artery disease. We have modified the Hildreth`s algorithm to estimate excursions of the ventricular wall on left ventricular images yielded by various imaging techniques. Tagging cine-MRI was carried out on 7 healthy volunteers. The original Hildreth method, the modified Hildreth method and the centerline method were applied to the outlines of the images obtained, to estimate excursion of the left ventricular wall and regional shortening and to evaluate the accuracy of these methods when measuring these parameters, compared to the values of these parameters measured actually using the attached tags. The accuracy of the original Hildreth method was comparable to that of the centerline method, while the modified Hildreth method was significantly more accurate than the centerline method (P<0.05). Regional shortening as estimated using the modified Hildreth method differed less from the actually measured regional shortening than did the shortening estimated using the centerline method (P<0.05). The modified Hildreth method allowed reasonable estimation of left ventricular wall excursion in all cases where it was applied. These results indicate that when applied to left ventriculograms for ventricular wall motion analysis, the modified Hildreth method is more useful than the original Hildreth method. (author)

  14. Simultaneous effects of slip and wall properties on MHD peristaltic motion of nanofluid with Joule heating

    Science.gov (United States)

    Hayat, T.; Nisar, Z.; Ahmad, B.; Yasmin, H.

    2015-12-01

    This paper is devoted to the magnetohydrodynamic (MHD) peristaltic transport of nanofluid in a channel with wall properties. Flow analysis is addressed in the presence of viscous dissipation, partial slip and Joule heating effects. Mathematical modelling also includes the salient features of Brownian motion and thermophoresis. Both analytic and numerical solutions are provided. Comparison between the solutions is shown in a very good agreement. Attention is focused to the Brownian motion parameter, thermophoresis parameter, Hartman number, Eckert number and Prandtl number. Influences of various parameters on skin friction coefficient, Nusselt and Sherwood numbers are also investigated. It is found that both the temperature and nanoparticles concentration are increasing functions of Brownian motion and thermophoresis parameters.

  15. Chest Wall Motion during Speech Production in Patients with Advanced Ankylosing Spondylitis

    Science.gov (United States)

    Kalliakosta, Georgia; Mandros, Charalampos; Tzelepis, George E.

    2007-01-01

    Purpose: To test the hypothesis that ankylosing spondylitis (AS) alters the pattern of chest wall motion during speech production. Method: The pattern of chest wall motion during speech was measured with respiratory inductive plethysmography in 6 participants with advanced AS (5 men, 1 woman, age 45 plus or minus 8 years, Schober test 1.45 plus or…

  16. Video-Based Motion Analysis

    Science.gov (United States)

    French, Paul; Peterson, Joel; Arrighi, Julie

    2005-04-01

    Video-based motion analysis has recently become very popular in introductory physics classes. This paper outlines general recommendations regarding equipment and software; videography issues such as scaling, shutter speed, lighting, background, and camera distance; as well as other methodological aspects. Also described are the measurement and modeling of the gravitational, drag, and Magnus forces on 1) a spherical projectile undergoing one-dimensional motion and 2) a spinning spherical projectile undergoing motion within a plane. Measurement and correction methods are devised for four common, major sources of error: parallax, lens distortion, discretization, and improper scaling.

  17. Electric-field-controlled suppression of Walker breakdown and chirality switching in magnetic domain wall motion

    Science.gov (United States)

    Chen, Hong-Bo; Li, You-Quan

    2016-07-01

    We theoretically study the dynamics of a magnetic domain wall controlled by an electric field in the presence of the spin flexoelectric interaction. We reveal that this interaction generates an effective spin torque and results in significant changes in the current-driven domain wall motion. In particular, the electric field can stabilize the domain wall motion, leading to strong suppression of the current-induced Walker breakdown and thus allowing a higher maximum wall velocity. We can furthermore use this electric-field control to efficiently switch the chirality of a moving domain wall in the steady regime.

  18. Antiferromagnetic domain wall motion driven by spin-orbit torques

    Science.gov (United States)

    Shiino, Takayuki; Oh, Se-Hyeok; Haney, Paul M.; Lee, Seo-Won; Go, Gyungchoon; Park, Byong-Guk; Lee, Kyung-Jin

    2016-01-01

    We theoretically investigate dynamics of antiferromagnetic domain walls driven by spin-orbit torques in antiferromagnet/heavy metal bilayers. We show that spin-orbit torques drive antiferromagnetic domain walls much faster than ferromagnetic domain walls. As the domain wall velocity approaches the maximum spin-wave group velocity, the domain wall undergoes Lorentz contraction and emits spin-waves in the terahertz frequency range. The interplay between spin-orbit torques and the relativistic dynamics of antiferromagnetic domain walls leads to the efficient manipulation of antiferromagnetic spin textures and paves the way for the generation of high frequency signals from antiferromagnets. PMID:27588878

  19. Current-driven magnetic domain wall motion and its real-time detection

    Science.gov (United States)

    Kim, Kab-Jin; Yoshimura, Yoko; Ono, Teruo

    2017-08-01

    Current-controlled magnetic domain wall motion has opened the possibility of a novel type of shift register memory device, which has been optimistically predicted to replace existing magnetic memories. Owing to this promising prospect, intensive work has been carried out during the last few decades. In this article, we first review the progress in the study of current-induced magnetic domain wall motion. Underlying mechanisms behind the domain wall motion, which have been discovered during last few decades, as well as technological achievements are presented. We then present our recent experimental results on the real-time detection of current-driven multiple magnetic domain wall motion, which directly demonstrates the operation of a magnetic domain wall shift register.

  20. Abdominal compliance, parasternal activation, and chest wall motion.

    Science.gov (United States)

    Cala, S J; Edyvean, J; Engel, L A

    1993-03-01

    We measured abdominal compliance (Cab) and rib cage displacement (delta Vrc) relative to abdominal displacement (delta Vab) during relaxation and tidal breathing in upright (U) and supine (S) postures in five normal subjects. In S, an abdominal binder was used to decrease Cab in two to five increments. We also measured the electrical activity of the parasternal muscle (EMGps) with the use of fine-wire intramuscular electrodes during CO2 rebreathing in U and in supine unbound (SU) and supine bound (SB) postures. During maximum binding (SB2), Cab decreased to 39 +/- 7% of the SU value (P = 0.01), matching Cab in U (P = 0.16). In the SB condition, the ratio of tidal delta Vrc/delta Vab to relaxation delta Vrc/delta Vab increased as Cab decreased, matching the data in U. For the group, this ratio decreased during SU to 47 +/- 10% (P = 0.02) but increased during SB2 to 86 +/- 7% (P = 0.18) of the value in U. During CO2 rebreathing, EMGps increased linearly with tidal volume (r > 0.727, P < 0.01). However, at any given tidal volume, the SU and SB2 EMGps were not significantly different (P = 0.12), and both were less than that in U (P < 0.02). The results suggest that the differences in chest wall motion between U and S may be due to the difference in Cab and not to different patterns of respiratory muscle recruitment. The mechanism may relate to changes in mechanical coupling between the diaphragm and the rib cage.

  1. Coupled Néel domain wall motion in sandwiched perpendicular magnetic anisotropy nanowires

    OpenAIRE

    Purnama, I.; Kerk, I. S.; Lim, G J; Lew, W. S.

    2015-01-01

    The operating performance of a domain wall-based magnetic device relies on the controlled motion of the domain walls within the ferromagnetic nanowires. Here, we report on the dynamics of coupled Néel domain wall in perpendicular magnetic anisotropy (PMA) nanowires via micromagnetic simulations. The coupled Néel domain wall is obtained in a sandwich structure, where two PMA nanowires that are separated by an insulating layer are stacked vertically. Under the application of high current densit...

  2. Assessment of left ventricular regional wall motion by color kinesis technique: comparison with angiographic findings.

    Science.gov (United States)

    Vermes, E; Guyon, P; Weingrod, M; Otmani, A; Soussana, C; Halphen, C; Leroy, G; Haïat, R

    2000-08-01

    The analysis of segmental wall motion using two-dimensional (2-D) echocardiography is subjective with high interobserver variability. Color kinesis is a new technique providing a color-encoded map of endocardial motion. We evaluated the accuracy of color kinesis and 2-D for assessment of regional asynergy compared with left ventricular angiography as a reference method. Fifteen patients admitted for myocardial infarction were studied by echocardiography the day before left ventricular angiography. The left ventricle was divided into seven segments. Each segment was classified by two independent observers as normal or abnormal in 2-D and color kinesis. Accuracy of color kinesis and 2-D was evaluated and compared to left ventricular angiography. Color kinesis is significantly superior to 2-D for all seven segments (mean 0.80/0.68, P = 0.05), except for the septum (0.67/0.60, P = NS). Interobserver variability studied by chi-square statistic is lower with color kinesis (0.70) than with 2-D (0.57). We conclude that these data suggest that color kinesis is a useful method for assessing systolic wall motion in all segments, except the septum and for improving the accuracy of segmental ventricular function and interobserver variability.

  3. Unstable equilibrium point in chaotic domain-wall motion and Ott-Grebogi-Yorke control

    Science.gov (United States)

    Okuno, H.; Takemura, Y.

    2001-06-01

    A method for finding the unstable equilibrium points in Bloch wall motion is proposed, which is important for controlling the chaotic domain-wall motion by using the Ott-Grebogi-Yorke (OGY) method. The dynamics of Bloch wall motion are expressed by a nonlinear differential equation with the terms of inertia, damping, restoring, and an external magnetic drive force. An equation is transformed into the difference equations by following the OGY method, approximating linearly around an unstable equilibrium point (a saddle point), and adding a controlling input. The unstable equilibrium points are obtained by using the return map and the condition of hyperbolic fixed point. The time series of domain-wall motion successfully controlled on the unstable equilibrium points by the OGY method is shown.

  4. Pattern recognition of abnormal left ventricle wall motion in cardiac MR.

    Science.gov (United States)

    Lu, Yingli; Radau, Perry; Connelly, Kim; Dick, Alexander; Wright, Graham

    2009-01-01

    There are four main problems that limit application of pattern recognition techniques for recognition of abnormal cardiac left ventricle (LV) wall motion: (1) Normalization of the LV's size, shape, intensity level and position; (2) defining a spatial correspondence between phases and subjects; (3) extracting features; (4) and discriminating abnormal from normal wall motion. Solving these four problems is required for application of pattern recognition techniques to classify the normal and abnormal LV wall motion. In this work, we introduce a normalization scheme to solve the first and second problems. With this scheme, LVs are normalized to the same position, size, and intensity level. Using the normalized images, we proposed an intra-segment classification criterion based on a correlation measure to solve the third and fourth problems. Application of the method to recognition of abnormal cardiac MR LV wall motion showed promising results.

  5. Pectoralis Muscle Flap Repair Reduces Paradoxical Motion of the Chest Wall in Complex Sternal Wound Dehiscence

    Science.gov (United States)

    Zeitani, Jacob; Russo, Marco; Pompeo, Eugenio; Sergiacomi, Gian Luigi; Chiariello, Luigi

    2016-01-01

    Background The aim of the study was to test the hypothesis that in patients with chronic complex sternum dehiscence, the use of muscle flap repair minimizes the occurrence of paradoxical motion of the chest wall (CWPM) when compared to sternal rewiring, eventually leading to better respiratory function and clinical outcomes during follow-up. Methods In a propensity score matching analysis, out of 94 patients who underwent sternal reconstruction, 20 patients were selected: 10 patients underwent sternal reconstruction with bilateral pectoralis muscle flaps (group 1) and 10 underwent sternal rewiring (group 2). Eligibility criteria included the presence of hemisternum diastases associated with multiple (≥3) bone fractures and radiologic evidence of synchronous chest wall motion (CWSM). We compared radiologically assessed (volumetric computed tomography) ventilatory mechanic indices such as single lung and global vital capacity (VC), diaphragm excursion, synchronous and paradoxical chest wall motion. Results Follow-up was 100% complete (mean 85±24 months). CWPM was inversely correlated with single lung VC (Spearman R=−0.72, p=0.0003), global VC (R=−0.51, p=0.02) and diaphragm excursion (R=−0.80, p=0.0003), whereas it proved directly correlated with dyspnea grade (Spearman R=0.51, p=0.02) and pain (R=0.59, p=0.005). Mean CWPM and single lung VC were both better in group 1, whereas there was no difference in CWSM, diaphragm excursion and global VC. Conclusion Our study suggests that in patients with complex chronic sternal dehiscence, pectoralis muscle flap reconstruction guarantees lower CWPM and greater single-lung VC when compared with sternal rewiring and it is associated with better clinical outcomes with less pain and dyspnea. PMID:27733997

  6. [Changes in left ventricular regional wall motion induced by Verapamil (author's transl)].

    Science.gov (United States)

    Barbieri, E; Allegri, P; Morlino, T; Vincenzi, M

    1980-01-01

    28 subjects with atherosclerotic lesions of coronary arteries were studied by means of cineventriculography both before and after IV administration of verapamil Regional wall motion has been analyzed by means of two different methods. Imporvement of regional wall motion has been demonstrated in about 65% of cases. No significant result has been achieved in segments corresponding to previous infarctions. Such a response does not differ substantially from that evoked by nitroglycerin or other calcium antagonist drugs.

  7. Domain wall motion driven by spin Hall effect—Tuning with in-plane magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Rushforth, A. W., E-mail: andrew.rushforth@nottingham.ac.uk [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

    2014-04-21

    This letter investigates the effects of in-plane magnetic anisotropy on the current induced motion of magnetic domain walls in systems with dominant perpendicular magnetic anisotropy, where accumulated spins from the spin Hall effect in an adjacent heavy metal layer are responsible for driving the domain wall motion. It is found that that the sign and magnitude of the domain wall velocity in the uniform flow regime can be tuned significantly by the in-plane magnetic anisotropy. These effects are sensitive to the ratio of the adiabatic and non-adiabatic spin transfer torque parameters and are robust in the presence of pinning and thermal fluctuations.

  8. Validity of acoustic quantification colour kinesis for detection of left ventricular regional wall motion abnormalities: a transoesophageal echocardiographic study.

    Science.gov (United States)

    Hartmann, T; Kolev, N; Blaicher, A; Spiss, C; Zimpfer, M

    1997-10-01

    Transoesophageal echocardiography is a sensitive monitor for intraoperative myocardial ischaemia. Colour kinesis is a new technology for echocardiographic assessment of regional wall motion based on acoustic quantification. We have examined the feasibility and accuracy of quantitative segmental analysis of colour kinesis images to provide objective evaluation of systolic regional wall motion during the perioperative period using transoesophageal echocardiography (TOE). Two-dimensional echocardiograms were obtained in the transgastric short-axis and long-axis views in 60 patients with coronary artery disease undergoing noncardiac surgery. End-systolic colour overlays superimposed on the grey scale images were obtained with colour kinesis to colour encode left ventricular endocardial motion throughout systole. These colour-encoded images were divided into segments and compared with corresponding conventional two-dimensional images. Six hundred of a potential 720 left ventricular wall segments were of sufficient resolution for grading by experts; they diagnosed wall motion abnormalities in 61 of these segments by a conventional method. In comparing the conventional TOE method with colour kinesis, there were 60 true positives, 482 true negatives, 57 false positives and 1 false negative result. This yielded a sensitivity of 98%, specificity of 89%, positive predictive value of 51% and negative predictive value of 100%. Translational and rotational movement of the heart and papillary muscle interference were common problems accounting for false positive diagnoses. We conclude that colour kinesis provides a basis for objective and on-line evaluation of left ventricular regional wall motion which is a sensitive but non-specific method. It may be a useful aid for the less experienced because it can potentially direct the anaesthetist's attention towards specific segments.

  9. Manipulating antiferromagnets with magnetic fields: Ratchet motion of multiple domain walls induced by asymmetric field pulses

    Science.gov (United States)

    Gomonay, O.; Kläui, M.; Sinova, J.

    2016-10-01

    Future applications of antiferromagnets (AFs) in many spintronics devices rely on the precise manipulation of domain walls. The conventional approach using static magnetic fields is inefficient due to the low susceptibility of AFs. Recently proposed electrical manipulation with spin-orbit torques is restricted to metals with a specific crystal structure. Here, we propose an alternative, broadly applicable approach: using asymmetric magnetic field pulses to induce controlled ratchet motion of AF domain walls. The efficiency of this approach is based on three peculiarities of AF dynamics. First, a time-dependent magnetic field couples with an AF order parameter stronger than a static magnetic field, which leads to higher mobility of the domain walls. Second, the rate of change of the magnetic field couples with the spatial variation of the AF order parameter inside the domain, and this enables a synchronous motion of multiple domain walls with the same structure. Third, tailored asymmetric field pulses in combination with static friction can prevent backward motion of domain walls and thus lead to the desired controlled ratchet effect. The proposed use of an external field, rather than internal spin-orbit torques, avoids any restrictions on size, conductivity, and crystal structure of the AF material. We believe that our approach paves a way for the development of AF-based devices based on the controlled motion of AF domain walls.

  10. Ab initio study of edge effect on relative motion of walls in carbon nanotubes.

    Science.gov (United States)

    Popov, Andrey M; Lebedeva, Irina V; Knizhnik, Andrey A; Lozovik, Yurii E; Potapkin, Boris V

    2013-01-14

    Interwall interaction energies of double-walled nanotubes with long inner and short outer walls are calculated as functions of coordinates describing relative rotation and displacement of the walls using van der Waals corrected density functional theory. The magnitude of corrugation and the shape of the potential energy relief are found to be very sensitive to changes of the shorter wall length at subnanometer scale and atomic structure of the edges if at least one of the walls is chiral. Threshold forces required to start relative motion of the short walls and temperatures at which the transition between diffusive and free motion of the short walls takes place are estimated. The edges are also shown to provide a considerable contribution to the barrier to relative rotation of commensurate nonchiral walls. For such walls, temperatures of orientational melting, i.e., the crossover from rotational diffusion to free relative rotation, are estimated. The possibility to produce nanotube-based bolt∕nut pairs and nanobearings is discussed.

  11. Coupled Néel domain wall motion in sandwiched perpendicular magnetic anisotropy nanowires.

    Science.gov (United States)

    Purnama, I; Kerk, I S; Lim, G J; Lew, W S

    2015-03-04

    The operating performance of a domain wall-based magnetic device relies on the controlled motion of the domain walls within the ferromagnetic nanowires. Here, we report on the dynamics of coupled Néel domain wall in perpendicular magnetic anisotropy (PMA) nanowires via micromagnetic simulations. The coupled Néel domain wall is obtained in a sandwich structure, where two PMA nanowires that are separated by an insulating layer are stacked vertically. Under the application of high current density, we found that the Walker breakdown phenomenon is suppressed in the sandwich structure. Consequently, the coupled Néel domain wall of the sandwich structure is able to move faster as compared to individual domain walls in a single PMA nanowire.

  12. Motion analysis of both ventricles using tagged MRI

    Science.gov (United States)

    Ozturk, Cengizhan; McVeigh, Elliot R.

    2000-04-01

    Although several methods exist for the analysis of tagged MRI images of the left ventricle (LV), analysis of the right ventricle (RV) remains challenging due to its complex anatomy and significant through plane motion. We present here preliminary results of our new motion analysis method, both for RV and LV, in healthy human volunteers. In this method, following standard myocardial and tag segmentation of cardiac gated cine tagged MR images; a 4D B-spline based parametric motion field was computed for a volume of interest encompassing both ventricles. Using this motion field, 3D displacements and strains were calculated on the RV and LV. We observed that for both chambers the circumferential strain (Ecc) decreased with a constant rate throughout systole. The systolic strain rate displayed spatial similarity not only for the LV but also for the RV. For RV free wall, mean systolic Ecc was -0.19 +/- 0.05 with an average coefficient of variability of 20%. The 4D B-spline based motion analysis technique for tagged MRI yields compatible results for the LV and gives consistent circumferential strain measures for the RV free wall. Tagged MRI based RV mechanical analysis can be used along with LV results for a more complete cardiac evaluation.

  13. Domain wall motion by the magnonic spin Seebeck effect.

    Science.gov (United States)

    Hinzke, D; Nowak, U

    2011-07-08

    The recently discovered spin Seebeck effect refers to a spin current induced by a temperature gradient in a ferromagnetic material. It combines spin degrees of freedom with caloric properties, opening the door for the invention of new, spin caloritronic devices. Using spin model simulations as well as an innovative, multiscale micromagnetic framework we show that magnonic spin currents caused by temperature gradients lead to spin transfer torque effects, which can drag a domain wall in a ferromagnetic nanostructure towards the hotter part of the wire. This effect opens new perspectives for the control and manipulation of domain structures.

  14. Normal left ventricular wall motion measured with two-dimensional myocardial tagging

    DEFF Research Database (Denmark)

    Qi, P; Thomsen, C; Ståhlberg, F;

    1993-01-01

    Using a myocardial tagging technique, normal left ventricular wall motion was studied in 3 true short axis views and a double oblique 4-chamber view in 14 and 11 volunteers, respectively. Three orthogonal directions of left ventricular motion were observed throughout the systole; a concentric...... contraction towards the center of the left ventricle, a motion of the base of the heart towards the apex, and a rotation of the left ventricle around its long axis. The direction of left ventricular rotation changed from early systole to late systole. The base and middle levels of the left ventricle rotated...... that MR imaging with myocardial tagging is a method that can be used to study normal left ventricular wall motion, and that is promising for future use in patient groups....

  15. Effect of Joule heating in current-driven domain wall motion

    OpenAIRE

    A., Yamaguchi; S., Nasu; H., Tanigawa; T., Ono; K., Miyake; Ko, Mibu; T., Shinjo

    2004-01-01

    It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed current. The sample temperature was 750 K for the threshold current density of 6.7×1011 A/m2 in a 10-nm-thick Ni81Fe19 wire with a width of 240 nm on thermally oxidized silicon substrate. The temperature ...

  16. Effect of Joule heating in current-driven domain wall motion

    OpenAIRE

    Yamaguchi, A.; Tanigawa, H.; Ono, T.; Nasu, S; Miyake, K.; Mibu, K.; Shinjo, T.

    2004-01-01

    It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed-current. The sample temperature was 750 K for the threshold current density of 6.7 x 10^11 A/m2 in a 10 nm-thick Ni81Fe19 wire with a width of 240 nm. The temperature was raised to 830 K for the current d...

  17. MOTION AND DEFORMATION OF VISCOUS DROP IN STOKES FLOW NEAR RIGID WALL

    Institute of Scientific and Technical Information of China (English)

    LU Hua-jian; ZHANG Hui-sheng

    2005-01-01

    A boundary integral method was developed for simulating the motion and deformation of a viscous drop in an axisymmetric ambient Stokes flow near a rigid wall and for direct calculating the stress on the wall. Numerical experiments by the method were performed for different initial stand-off distances of the drop to the wall, viscosity ratios, combined surface tension and buoyancy parameters and ambient flow parameters. Numerical results show that due to the action of ambient flow and buoyancy the drop is compressed and stretched respectively in axial and radial directions when time goes. When the ambient flow action is weaker than that of the buoyancy the drop raises and bends upward and the stress on the wall induced by drop motion decreases when time advances. When the ambient flow action is stronger than that of the buoyancy the drop descends and becomes flatter and flatter as time goes. In this case when the initial stand-off distance is large the stress on the wall increases as the drop evolutes but when the stand-off distance is small the stress on the wall decreases as a result of combined effects of ambient flow, buoyancy and the stronger wall action to the flow. The action of the stress on the wall induced by drop motion is restricted in an area near the symmetric axis, which increases when the initial stand-off distance increases.When the initial stand-off distance increases the stress induced by drop motion decreases substantially. The surface tension effects resist the deformation and smooth the profile of the drop surfaces. The drop viscosity will reduce the deformation and migration of the drop.

  18. Domain wall motions in perpendicularly magnetized CoFe/Pd multilayer nanowire

    DEFF Research Database (Denmark)

    Meng, Zhaoliang; Kumar, Manoj; Qiu, Jinjun;

    2014-01-01

    Current-induced domain wall (DW) motion is investigated in a 600nm wide nanowire using multilayer film with a structure of Ta(5nm)/Pd(5nm)/[CoFe(0.4nm)/Pd(1.2nm)]15/Ta(5nm) in terms of anomalous Hall effect measurements. It is found that motion of DWs can be driven by a current density as low as 1...

  19. A model-based time-reversal of left ventricular motion improves cardiac motion analysis using tagged MRI data

    Directory of Open Access Journals (Sweden)

    Cook Larry T

    2008-05-01

    Full Text Available Abstract Background Myocardial motion is an important observable for the assessment of heart condition. Accurate estimates of ventricular (LV wall motion are required for quantifying myocardial deformation and assessing local tissue function and viability. Harmonic Phase (HARP analysis was developed for measuring regional LV motion using tagged magnetic resonance imaging (tMRI data. With current computer-aided postprocessing tools including HARP analysis, large motions experienced by myocardial tissue are, however, often intractable to measure. This paper addresses this issue and provides a solution to make such measurements possible. Methods To improve the estimation performance of large cardiac motions while analyzing tMRI data sets, we propose a two-step solution. The first step involves constructing a model to describe average systolic motion of the LV wall within a subject group. The second step involves time-reversal of the model applied as a spatial coordinate transformation to digitally relax the contracted LV wall in the experimental data of a single subject to the beginning of systole. Cardiac tMRI scans were performed on four healthy rats and used for developing the forward LV model. Algorithms were implemented for preprocessing the tMRI data, optimizing the model parameters and performing the HARP analysis. Slices from the midventricular level were then analyzed for all systolic phases. Results The time-reversal operation derived from the LV model accounted for the bulk portion of the myocardial motion, which was the average motion experienced within the overall subject population. In analyzing the individual tMRI data sets, removing this average with the time-reversal operation left small magnitude residual motion unique to the case. This remaining residual portion of the motion was estimated robustly using the HARP analysis. Conclusion Utilizing a combination of the forward LV model and its time reversal improves the performance of

  20. Quantitative assessment of human motion using video motion analysis

    Science.gov (United States)

    Probe, John D.

    1993-01-01

    In the study of the dynamics and kinematics of the human body a wide variety of technologies has been developed. Photogrammetric techniques are well documented and are known to provide reliable positional data from recorded images. Often these techniques are used in conjunction with cinematography and videography for analysis of planar motion, and to a lesser degree three-dimensional motion. Cinematography has been the most widely used medium for movement analysis. Excessive operating costs and the lag time required for film development, coupled with recent advances in video technology, have allowed video based motion analysis systems to emerge as a cost effective method of collecting and analyzing human movement. The Anthropometric and Biomechanics Lab at Johnson Space Center utilizes the video based Ariel Performance Analysis System (APAS) to develop data on shirtsleeved and space-suited human performance in order to plan efficient on-orbit intravehicular and extravehicular activities. APAS is a fully integrated system of hardware and software for biomechanics and the analysis of human performance and generalized motion measurement. Major components of the complete system include the video system, the AT compatible computer, and the proprietary software.

  1. Echocardiographic Wall Motion Abnormality in Posterior Myocardial Infarction: The Diagnostic Value of Posterior Leads

    Directory of Open Access Journals (Sweden)

    A Darehzereshki

    2008-06-01

    Full Text Available Background: For the purpose of ascertaining myocardial infarction (MI and ischemia, the sensitivity of the initial 12-lead ECG is inadequate. It is risky to diagnose posterior MI using only precordial reciprocal changes, since the other leads may be more optimally positioned for the identification of electrocardiographic changes. In this study, we evaluated the relationship between electrocardiography changes and wall motion abnormalities in patients with posterior MI for earlier and better diagnosis of posterior MI.Methods: In this prospective cross-sectional study, we enrolled patients with posterior MI who had come to the Emergency Department of Shariati Hospital with their first episode of chest pain. A 12-lead surface electrocardiogram using posterior leads (V7-V9 was performed for all participants. Patients with ST elevation >0.05 mV or pathologic Q wave in the posterior leads, as well as those with specific changes indicating posterior MI in V1-V2, were evaluated by echocardiography in terms of wall motion abnormalities. All data were analyzed using SPSS and p<0.05 were considered statistically significant.Results: Of a total 79 patients enrolled, 48 (60.8% were men, and the mean age was 57.35±8.22 years. Smoking (54.4% and diabetes (48% were the most prevalent risk factors. In the echocardiographic evaluation, all patients had wall motion abnormalities in the left ventricle and 19 patients (24.1% had wall motion abnormalities in the right ventricle. The most frequent segment with motion abnormality among the all patients was the mid-posterior. The posterior leads showed better positive predictive value than the anterior leads for posterior wall motion abnormality.Conclusion: Electrocardiography of the posterior leads in patients with acute chest pain can help in earlier diagnosis and in time treatment of posterior MI.

  2. Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories

    KAUST Repository

    Ivanov, Yurii P.

    2016-05-03

    Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices. © 2016 American Chemical Society.

  3. Numerical Simulation of Microcarrier Motion in a Rotating Wall Vessel Bioreactor

    Institute of Scientific and Technical Information of China (English)

    ZHI-HAO JU; TIAN-QING LIU; XUE-HU MA; ZHAN-FENG CUI

    2006-01-01

    Objective To analyze the forces of rotational wall vessel (RWV) bioreactor on small tissue pieces or microcarrier particles and to determine the tracks of microcarrier particles in RWV bioreactor. Methods The motion of the microcarrier in the rotating wall vessel (RWV) bioreactor with both the inner and outer cylinders rotating was modeled by numerical simulation. Results The continuous trajectory of microcarrier particles, including the possible collision with the wall was obtained. An expression between the minimum rotational speed difference of the inner and outer cylinders and the microcarrier particle or aggregate radius could avoid collisions with either wall. The range of microcarrier radius or tissue size, which could be safely cultured in the RWV bioreactor, in terms of shear stress level, was determined. Conclusion The model works well in describing the trajectory of a heavier microcarrier particle in rotating wall vessel.

  4. Magnetic domain wall motion in notch patterned permalloy nanowire devices

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ting-Chieh; Kuo, Cheng-Yi; Mishra, Amit K.; Das, Bipul; Wu, Jong-Ching, E-mail: phjcwu@cc.ncue.edu.tw

    2015-11-01

    We report a study of magnetization reversal process of notch-patterned permalloy (Py) nanowires (NWs) by using an in-situ magnetic force microscopy (MFM). Three neighboring straight NWs and an individual straight NW with discs connected to the wires ends are fabricated by standard electron beam lithography through a lift-off technique. MFM images are taken in the presence of an in-plane magnetic field applied along the wires length. As a result, the nucleation, pinning and depinning of domain walls (DWs) along the NW are observed. The artificial constraints (notch) in such symmetrical geometry of NWs indeed serve as pinning sites to pin the DWs. The nature of magnetization reversal, pinning field and depinning field for the DWs that are observed in these permalloy NWs, indicate the key roles of notch depth, the terminal connection structure of NW end and the inter-wire interaction among the NWs. The in-situ MFM measurements are examined with the micromagnetic simulations. Consequently, good agreements are obtained for the DW structures and the effect of DWs pining/depinning, however a dissimilarity in experimental and simulation observations for the direction of propagation of DWs in NWs needs further investigation.

  5. Distance-from-the-wall scaling of turbulent motions in wall-bounded flows

    Science.gov (United States)

    Baidya, R.; Philip, J.; Hutchins, N.; Monty, J. P.; Marusic, I.

    2017-02-01

    An assessment of self-similarity in the inertial sublayer is presented by considering the wall-normal velocity, in addition to the streamwise velocity component. The novelty of the current work lies in the inclusion of the second velocity component, made possible by carefully conducted subminiature ×-probe experiments to minimise the errors in measuring the wall-normal velocity. We show that not all turbulent stress quantities approach the self-similar asymptotic state at an equal rate as the Reynolds number is increased, with the Reynolds shear stress approaching faster than the streamwise normal stress. These trends are explained by the contributions from attached eddies. Furthermore, the Reynolds shear stress cospectra, through its scaling with the distance from the wall, are used to assess the wall-normal limits where self-similarity applies within the wall-bounded flow. The results are found to be consistent with the recent prediction from the work of Wei et al. ["Properties of the mean momentum balance in turbulent boundary layer, pipe and channel flows," J. Fluid Mech. 522, 303-327 (2005)], Klewicki ["Reynolds number dependence, scaling, and dynamics of turbulent boundary layers," J. Fluids Eng. 132, 094001 (2010)], and others that the self-similar region starts and ends at z+˜O (√{δ+}) and O (δ+) , respectively. Below the self-similar region, empirical evidence suggests that eddies responsible for turbulent stresses begin to exhibit distance-from-the-wall scaling at a fixed z+ location; however, they are distorted by viscous forces, which remain a leading order contribution in the mean momentum balance in the region z+≲O (√{δ+}) , and thus result in a departure from self-similarity.

  6. Nonmonotonic effects of perpendicular magnetic anisotropy on current-driven vortex wall motions in magnetic nanostripes

    Science.gov (United States)

    Su, Yuan-Chang; Lei, Hai-Yang; Hu, Jing-Guo

    2015-09-01

    In a magnetic nanostripe, the effects of perpendicular magnetic anisotropy (PMA) on the current-driven horizontal motion of vortex wall along the stripe and the vertical motion of the vortex core are studied by micromagnetic simulations. The results show that the horizontal and vertical motion can generally be monotonously enhanced by PMA. However, when the current is small, a nonmonotonic phenomenon for the horizontal motion is found. Namely, the velocity of the horizontal motion firstly decreases and then increases with the increase of the PMA. We find that the reason for this is that the PMA can firstly increase and then decrease the confining force induced by the confining potential energy. In addition, the PMA always enhances the driving force induced by the current. Project supported by the National Natural Science Foundation of China (Grant Nos. 11247026 and 11374253).

  7. Field-driven Domain Wall Motion in Ferromagnetic Nanowires with Bulk Dzyaloshinskii-Moriya Interaction

    Science.gov (United States)

    Zhuo, Fengjun; Sun, Z. Z.

    2016-01-01

    Field-driven domain wall (DW) motion in ferromagnetic nanowires with easy- and hard-axis anisotropies was studied theoretically and numerically in the presence of the bulk Dzyaloshinskii-Moriya interaction (DMI) based on the Landau-Lifshitz-Gilbert equation. We propose a new trial function and offer an exact solution for DW motion along a uniaxial nanowire driven by an external magnetic field. A new strategy was suggested to speed up DW motion in a uniaxial magnetic nanowire with large DMI parameters. In the presence of hard-axis anisotropy, we find that the breakdown field and velocity of DW motion was strongly affected by the strength and sign of the DMI parameter under external fields. This work may be useful for future magnetic information storage devices based on DW motion. PMID:27118064

  8. Impairment of left ventricular regional wall motion in diabetes mellitus without coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Ken`ya; Shimonagata, Tuyoshi; Nanto, Shinsuke; Kuroda, Akio; Morozumi, Takakazu; Kamado, Kenji; Nagata, Seiki [Kansai Rosai Hospital, Amagasaki, Hyogo (Japan); Yamasaki, Yoshimitsu

    1996-09-01

    To elucidate the mechanisms of diabetic cardiomyopathy, dual SPECT imaging with thallium-201 (Tl-201) and I-123 beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP), a branched analogue of free fatty acid (FFA), and dipyridamole-infusion Tl-201 scintigraphy were performed in 28 NIDDM patients without coronary artery disease. Twenty eight patients were divided into two groups based on the presence of wall motion abnormalities on cineangiographic left ventriculography (LVG). Nineteen patients with normal wall motion documented on LVG (group A) out of 28 evaluated patients demonstrated normal Tl-201 and I-123 BMIPP uptake in dual SPECT imaging, whereas 9 patients with reduced wall motion (group B) demonstrated reduced I-123 BMIPP uptake when compared with Tl-201 uptake. On dipyridamole-infusion Tl-201 scintigraphy, transient perfusion defects were demonstrated in 4 patients of group B and two patients of group A (p<0.05). These results suggest that small vessel disease and the impairment of myocardial free fatty acid metabolism are etiologic or contributory factors for regional wall motion abnormality in diabetic cardiomyopathy. (author)

  9. Acute myocarditis with normal wall motion detected with 2D speckle tracking echocardiography

    Directory of Open Access Journals (Sweden)

    Thomas Sturmberger

    2016-05-01

    Full Text Available We present the case of a 26-year-old male with acute tonsillitis who was referred for coronary angiography because of chest pain, elevated cardiac biomarkers, and biphasic T waves. The patient had no cardiovascular risk factors. Echocardiography showed no wall motion abnormalities and no pericardial effusion. 2D speckle tracking revealed distinct decreased regional peak longitudinal systolic strain in the lateral and posterior walls. Ischemic disease was extremely unlikely in view of his young age, negative family history regarding coronary artery disease, and lack of regional wall motion abnormalities on the conventional 2D echocardiogram. Coronary angiography was deferred as myocarditis was suspected. To confirm the diagnosis, cardiac magnetic resonance tomography (MRT was performed, showing subepicardial delayed hyperenhancement in the lateral and posterior walls correlating closely with the strain pattern obtained by 2D speckle tracking echocardiography. With a working diagnosis of acute myocarditis associated with acute tonsillitis, we prescribed antibiotics and nonsteroidal anti-inflammatory drugs. The patient’s clinical signs resolved along with normalization of serum creatine kinase (CK levels, and the patient was discharged on the third day after admission. Learning points: • Acute myocarditis can mimic acute coronary syndromes. • Conventional 2D echocardiography lacks specific features for detection of subtle regional wall motion abnormalities. • 2D speckle tracking expands the scope of echocardiography in identifying myocardial dysfunction derived from edema in acute myocarditis.

  10. New techniques for the assessment of regional left ventricular wall motion.

    Science.gov (United States)

    Garcia-Fernandez, Miguel Angel; Bermejo, Javier; Perez-David, Esther; Lopez-Fernandez, Teresa; Ledesma, Maria Jesus; Caso, Pio; Malpica, Norberto; Santos, Andres; Moreno, Mar; Desco, Manuel

    2003-10-01

    The assessment of regional left ventricular (LV) function has been an important yet unresolved problem since the introduction of echocardiography as a diagnostic tool. Abnormal regional LV wall motion is an early finding in multiple cardiac pathologies and its diagnosis is of critical importance. In the last few years diagnostic procedures based on combined use of existing echocardiographic technologies were geared toward improving the accuracy of detection of baseline and/or induced regional wall motion abnormalities. One of the assumptions is that the combination of reduced LV wall thickening and reduced myocardial velocities can be used to accurately diagnose regional myocardial dysfunction. In this article we will discuss several new techniques for the quantification of regional LV function using Doppler echocardiography.

  11. Domain Wall Motion in Magnetic Nanostrips under the Influence of Rashba Field

    Directory of Open Access Journals (Sweden)

    Vito Puliafito

    2012-01-01

    Full Text Available Spin-orbit Rashba effect applies a torque on the magnetization of a ferromagnetic nanostrip in the case of structural inversion asymmetry, also affecting the steady domain wall motion induced by a spin-polarized current. This influence is here analytically studied in the framework of the extended Landau-Lifshitz-Gilbert equation, including the Rashba effect as an additive term of the effective field. Results of previous micromagnetic simulations and experiments have shown that this field yields an increased value of the Walker breakdown current together with an enlargement of the domain wall width. In order to analytically describe these results, the standard travelling wave ansatz for the steady domain wall motion is here adopted. Results of our investigations reveal the impossibility to reproduce, at the same time, the previous features and suggest the need of a more sophisticated model whose development requires, in turn, additional information to be extracted from ad hoc micromagnetic simulations.

  12. Analytical Analysis of Motion Separability

    Directory of Open Access Journals (Sweden)

    Marjan Hadian Jazi

    2013-01-01

    Full Text Available Motion segmentation is an important task in computer vision and several practical approaches have already been developed. A common approach to motion segmentation is to use the optical flow and formulate the segmentation problem using a linear approximation of the brightness constancy constraints. Although there are numerous solutions to solve this problem and their accuracies and reliabilities have been studied, the exact definition of the segmentation problem, its theoretical feasibility and the conditions for successful motion segmentation are yet to be derived. This paper presents a simplified theoretical framework for the prediction of feasibility, of segmentation of a two-dimensional linear equation system. A statistical definition of a separable motion (structure is presented and a relatively straightforward criterion for predicting the separability of two different motions in this framework is derived. The applicability of the proposed criterion for prediction of the existence of multiple motions in practice is examined using both synthetic and real image sequences. The prescribed separability criterion is useful in designing computer vision applications as it is solely based on the amount of relative motion and the scale of measurement noise.

  13. Analysis methods for facial motion

    Directory of Open Access Journals (Sweden)

    Katsuaki Mishima

    2009-05-01

    Full Text Available Objective techniques to evaluate a facial movement are indispensable for the contemporary treatment of patients with motor disorders such as facial paralysis, cleft lip, postoperative head and neck cancer, and so on. Recently, computer-assisted, video-based techniques have been devised and reported as measuring systems in which facial movements can be evaluated quantitatively. Commercially available motion analysis systems, in which a stereo-measuring technique with multiple cameras and markers to facilitate search of matching among images through all cameras, also are utilized, and are used in many measuring systems such as video-based systems. The key is how the problems of facial movement can be extracted precisely, and how useful information for the diagnosis and decision-making process can be derived from analyses of facial movement. Therefore, it is important to discuss which facial animations should be examined, and whether fixation of the head and markers attached to the face can hamper natural facial movement.

  14. Domain wall motion and Barkhausen effect in magnetic nanoparticles for EOR applications

    Science.gov (United States)

    Baig, Mirza Khurram; Soleimani, Hassan; Yahya, Noorhana

    2016-11-01

    The domain wall motion in magnetic nanoparticles is a useful parameter of study. The subject of this research is to study of the phenomenon of discontinuous domain wall motion, or the Barkhausen Effect in magnetic nanoparticles. In this work hematite (Fe2O3) nanoparticles have been synthesized using sol-gel auto-combustion and characterized using X-ray diffraction, Field emission scanning electron microscopy (FESEM), Transmission electron microscope (TEM) and Vibrating sample magnetometer (VSM) for crystal structure, morphology, shape, size and magnetic properties respectively. The FESEM and TEM results show that the particles are spherical in nature and average size is 60nm that is suitable for domain walls and barkhuasen effect. The VSM results show high coercivity 175 Oe and low saturation magnetization due to domain wall pinning and barkhausen effect. The size and magnetic properties reveals the existence of domain walls in the synthesized sample. The magnetic properties confirm the energy losses due to domain wall pinning, discontinuous domain rotation or barkhausen effect during magnetization which is useful for oil-water interfacial tension reduction and viscosity of oil. The high surface charge of magnetic nanoparticles and adsorption at the rock surface is useful for wettability alteration of rocks.

  15. Motion Analysis Based on Invertible Rapid Transform

    Directory of Open Access Journals (Sweden)

    J. Turan

    1999-06-01

    Full Text Available This paper presents the results of a study on the use of invertible rapid transform (IRT for the motion estimation in a sequence of images. Motion estimation algorithms based on the analysis of the matrix of states (produced in the IRT calculation are described. The new method was used experimentally to estimate crowd and traffic motion from the image data sequences captured at railway stations and at high ways in large cities. The motion vectors may be used to devise a polar plot (showing velocity magnitude and direction for moving objects where the dominant motion tendency can be seen. The experimental results of comparison of the new motion estimation methods with other well known block matching methods (full search, 2D-log, method based on conventional (cross correlation (CC function or phase correlation (PC function for application of crowd motion estimation are also presented.

  16. Usefulness of coronary flow reserve over regional wall motion when added to dual-imaging dipyridamole echocardiography.

    Science.gov (United States)

    Rigo, Fausto; Richieri, Margherita; Pasanisi, Emilio; Cutaia, Valeria; Zanella, Carlo; Della Valentina, Patrizia; Di Pede, Francesco; Raviele, Antonio; Picano, Eugenio

    2003-02-01

    Vasodilator stress echocardiography allows semi-simultaneous imaging of left anterior descending (LAD) coronary flow and regional wall function. To assess the relative (and additive?) value of regional flow and function for noninvasive identification of angiographically assessed LAD disease in patients with chest pain syndrome, we studied 230 consecutive in-hospital patients (134 men, aged 63.5 +/- 11 years) with chest pain syndrome and normal regional and global left ventricular function. All patients underwent stress echocardiography with dipyridamole (up to 0.84 mg/kg over 10 minutes), including wall motion analysis by 2-dimensional echocardiography and coronary flow reserve (CFR) evaluation of the LAD artery by Doppler, with or without contrast injection. A new regional wall motion abnormality in >or=2 contiguous segments was required for 2-dimensional echocardiographic positivity. CFR was evaluated as the ratio of dipyridamole to peak diastolic coronary blood flow velocity at rest. All patients underwent coronary angiography within 60 days; a quantitatively assessed diameter reduction >50% of the LAD artery was considered significant. Of the 230 patients, 70 had LAD disease. A regional wall motion abnormality in LAD territory was present in 52 patients, and reduced CFR (<1.9) in 62 patients. Sensitivity for detecting LAD disease was 74% for 2-dimensional echocardiography (95% confidence interval [CI] 64% to 84%) and 81% for CFR <1.9 (95% CI 72% to 90%); specificity was 91% (95% CI 87% to 96%) for 2-dimensional echocardiography and 84% for CFR (95% CI 79% to 90%). Accuracy was 86% for 2-dimensional echocardiography (95% CI 82% to 91%) and 83.5% for CFR (95% CI 79% to 88%). When 2-dimensional echocardiography and CFR criteria were considered, sensitivity increased to 93% (95% CI 87% to 99%), with 80.6% specificity (95% CI 74.5% to 86.7%). CFR was assessed during vasodilator stress echocardiography. Its diagnostic accuracy for detecting LAD disease was comparable

  17. Current-driven vortex domain wall motion in wire-tube nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Espejo, A. P. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Vidal-Silva, N. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); López-López, J. A. [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Goerlitz, D.; Nielsch, K. [Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Escrig, J. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Av. Ecuador 3493, 9170124 Santiago (Chile)

    2015-03-30

    We have investigated the current-driven domain wall motion in nanostructures comprised of a pair of nanotube and nanowire segments. Under certain values of external magnetic fields, it is possible to pin a vortex domain wall in the transition zone between the wire and tube segments. We explored the behavior of this domain wall under the action of an electron flow applied in the opposite direction to the magnetic field. Thus, for a fixed magnetic field, it is possible to release a domain wall pinned simply by increasing the intensity of the current density, or conversely, for a fixed current density, it is possible to release the domain wall simply decreasing the magnetic external field. When the domain wall remains pinned due to the competition between the current density and the magnetic external field, it exhibits a oscillation frequency close to 8 GHz. The amplitude of the oscillations increases with the current density and decreases over time. On the other hand, when the domain wall is released and propagated through the tube segment, this shows the standard separation between a steady and a precessional regime. The ability to pin and release a domain wall by varying the geometric parameters, the current density, or the magnetic field transforms these wire-tube nanostructures in an interesting alternative as an on/off switch nano-transistor.

  18. Analytical Analysis of Motion Separability

    OpenAIRE

    Marjan Hadian Jazi; Alireza Bab-Hadiashar; Reza Hoseinnezhad

    2013-01-01

    Motion segmentation is an important task in computer vision and several practical approaches have already been developed. A common approach to motion segmentation is to use the optical flow and formulate the segmentation problem using a linear approximation of the brightness constancy constraints. Although there are numerous solutions to solve this problem and their accuracies and reliabilities have been studied, the exact definition of the segmentation problem, its theoretical feasibility an...

  19. Feasibility and Reproducibility of Two-Dimensional Wall Motion Tracking (WMT) in Fetal Echocardiography

    Science.gov (United States)

    Enzensberger, Christian; Achterberg, Friederike; Degenhardt, Jan; Wolter, Aline; Graupner, Oliver; Herrmann, Johannes; Axt-Fliedner, Roland

    2017-01-01

    Objective The primary objective of this study was to determine the feasibility and reproducibility of 2-dimensional speckle tracking imaging based on the wall motion tracking (WMT) technique in fetal echocardiography. The secondary objective was to compare left and right ventricular global and segmental longitudinal peak strain values. Methods A prospective cross-sectional study was performed. Global and segmental longitudinal peak strain values of the left ventricle (LV) and right ventricle (RV) were assessed prospectively. Based on apical 4-chamber views, cine loops were acquired and digitally stored. Strain analysis was performed offline. Intra- and interobserver variabilities were analyzed. Results A total of 29 healthy fetuses with an echocardiogram performed between 19 and 37 weeks of gestation were included. Analysis was performed with a temporal resolution of 60 frames per second (fps). For both examiners, in all cases Cronbach’s alpha was>0.7. The interobserver variability showed a strong agreement in 50% of the segments (ICC 0.71–0.90). The global strain values for LV and RV were −16.34 and −14.65%, respectively. Segmental strain analysis revealed a basis to apex gradient with the lowest strain values in basal segments and the highest strain values in apical segments. Conclusion The assessment of fetal myocardial deformation parameters by 2D WMT is technically feasible with good reproducibility. PMID:28210715

  20. Current driven domain wall motion in rare-earth transition metal alloys with perpendicular magnetic anisotropy.

    Science.gov (United States)

    Li, Songtian; Liu, Xiaoxi; Morisako, Akimistu

    2012-09-01

    The domain wall movement behaviors under current combining with magnetic field in perpendicularly magnetized TbFeCo wire were studied by a polar magneto-optical Kerr effect microscope. The velocity for domain wall creeping along electrons flowing direction was found to be apparently higher than that of domain wall creeping against electrons flowing, which is the signature of the spin transfer torque effect. By employing the modified field-driven creep motion law, a spin transfer efficiency of 2.7 Oe cm2/10(6) A was determined for TbFeCo wire by treating the spin transfer torque as an effective field adding to the external field. The high spin transfer efficiency suggests that perpendicularly magnetized system with sharp domain walls in TbFeCo film shows high superiorities for applications in spin transfer torque based devices compared with in-plane magnetized systems.

  1. Static inelastic analysis of RC shear walls

    Science.gov (United States)

    Chen, Qin; Qian, Jiaru

    2002-06-01

    A macro-model of a reinforced concrete (RC) shear wall is developed for static inelastic analysis. The model is composed of RC column elements and RC membrane elements. The column elements are used to model the boundary zone and the membrane elements are used to model the wall panel. Various types of constitutive relationships of concrete could be adopted for the two kinds of elements. To perform analysis, the wall is divided into layers along its height. Two adjacent layers are connected with a rigid beam. There are only three unknown displacement components for each layer. A method called single degree of freedom compensation is adopted to solve the peak value of the capacity curve. The post-peak stage analysis is performed using a forced iteration approach. The macro-model developed in the study and the complete process analysis methodology are verified by the experimental and static inelastic analytical results of four RC shear wall specimens.

  2. Domain wall motion and precursor dynamics in PbZrO3

    Science.gov (United States)

    Puchberger, S.; Soprunyuk, V.; Majchrowski, A.; Roleder, K.; Schranz, W.

    2016-12-01

    Single crystals of PbZrO3 have been studied by dynamic mechanical analysis measurements in the low-frequency range f =0.02 -50 Hz. The complex Young's modulus exhibits a quite rich behavior and depends strongly on the direction of the applied dynamic force. In pseudocubic [100] c direction, we found intrinsic elastic behavior as expected from the Landau theory; at the antiferroelectric transition Tc≈510 K, a downwards cusp anomaly in Y' accompanied by a peak in Y'' points to a quadratic/linear order parameter/strain coupling in the Landau free energy. Both anomalies are increasing with decreasing frequency showing that the measurements are performed in the limit ω τth>1 . Frequency scans around Tc show energy dissipation, which could result from interphase boundary motion and/or heat diffusion. Above Tc, we observe a pronounced precursor softening, quite similar as it was found in other perovskites, which can be perfectly fitted including isotropic order parameter fluctuations. The low-frequency elastic response in [110] c direction is different. Below Tc, we find in addition to the intrinsic anomaly a strong contribution from ferroelastic domains, which leads to an additional softening in Y'. With decreasing temperatures this superelastic softening gradually disappears, due to an increasing relaxation time τDW for domain wall motion, indicating glassy behavior of domain freezing in PbZrO3. In contrast to the [100] c direction, for forces along [110] c, we found a pronounced precursor hardening, starting at about 60 K above Tc. Since this anomaly is of dynamic nature, starting at the same temperature as the observed birefringence and piezoelectric anomalies [Ko et al. Phys. Rev. B 87, 184110 (2013), 10.1103/PhysRevB.87.184110], we conclude that it originates from slow dynamic polar clusters, which freeze at T*≈550 K>Tc .

  3. Static inelastic analysis of RC shear walls

    Institute of Scientific and Technical Information of China (English)

    陈勤; 钱稼茹

    2002-01-01

    A macro-model of a reinforced concrete (RC) shear wall is developed for static inelastic analysis. The model iscomposed of RC column elements and RC membrane elements. The column elements are used to model the boundary zone andthe membrane elements are used to model the wall panel. Various types of constitutive relationships of concrete could beadopted for the two kinds of elements. To perform analysis, the wall is divided into layers along its height. Two adjacent layersare connected with a rigid beam. There are only three unknown displacement components for each layer. A method called singledegree of freedom compensation is adopted to solve the peak value of the capacity curve. The post-peak stage analysis isperformed using a forced iteration approach. The macro-model developed in the study and the complete process analysismethodology are verified by the experimental and static inelastic analytical results of four RC shear wall specimens.

  4. Dynamic radionuclide determination of regional left ventricular wall motion using a new digital imaging device

    Science.gov (United States)

    Steele, P.; Kirch, D.

    1975-01-01

    In 47 men with arteriographically defined coronary artery disease comparative studies of left ventricular ejection fraction and segmental wall motion were made with radionuclide data obtained from the image intensifier camera computer system and with contrast cineventriculography. The radionuclide data was digitized and the images corresponding to left ventricular end-diastole and end-systole were identified from the left ventricular time-activity curve. The left ventricular end-diastolic and end-systolic images were subtracted to form a silhouette difference image which described wall motion of the anterior and inferior left ventricular segments. The image intensifier camera allows manipulation of dynamically acquired radionuclide data because of the high count rate and consequently improved resolution of the left ventricular image.

  5. Current induced domain wall motion in nanostripes with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Su Jung; Tan, Reasmey P.; Chun, Byong Sun [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Young Keun, E-mail: ykim97@korea.ac.k [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2010-11-15

    We report micromagnetic modeling results of current induced domain wall (DW) motion in magnetic devices with perpendicular magnetic anisotropy by solving the Landau-Lifschitz-Gilbert equation including adiabatic and non-adiabatic terms. A nanostripe model system with dimensions of 500 nm (L)x25 nm (W)x5 nm (H) was selected for calculating the DW motion and its width, as a function of various parameters such as non-adiabatic contribution, anisotropy constant (K{sub u}), saturation magnetization (M{sub s}), and temperature (T). The DW velocity was found to increase when the values of K{sub u} and T were increased and the M{sub s} value decreased. In addition, a reduction of the domain wall width could be achieved by increasing K{sub u} and lowering M{sub s} values regardless of the non-adiabatic constant value.

  6. Usefulness of color kinesis imaging for evaluation of regional right ventricular wall motion in patients with surgically repaired tetralogy of Fallot.

    Science.gov (United States)

    Hayabuchi, Y; Matsuoka, S; Kubo, M; Kuroda, Y

    1998-11-15

    We evaluated regional right ventricular wall motion during systole in patients with surgically repaired tetralogy of Fallot (TOF) using color kinesis imaging. Color kinesis images were obtained in a subcostal sagittal view from 19 patients with repaired TOF (TOF group), aged 3 to 5 years, and 20 age-matched normal subjects (control group). For regional wall motion analysis, the endocardial motion distance and the fractional area change (FAC) were calculated for 6 segments obtained from color kinesis images. The endocardial inward excursion distances and the FACs in the upper, middle, and lower posterior segments of the TOF group were significantly greater than those of the control group (p kinesis measurements was excellent (y = 1.14x - 1.30, r = 0.87 for the endocardial inward excursion, and y = 1.03x +/- 0.56, r = 0.91 for the FAC). In conclusion, color kinesis is a useful method for assessing regional right ventricular wall motion. Segmental analysis of color kinesis images provides accurate, automated, and quantitative diagnosis of regional right ventricular wall motion abnormalities in patients with surgically repaired TOF.

  7. Motion of a particle between two parallel plane walls in low-Reynolds-number Poiseuille flow

    Science.gov (United States)

    Staben, Michelle E.; Zinchenko, Alexander Z.; Davis, Robert H.

    2003-06-01

    A new boundary-integral algorithm for the motion of a particle between two parallel plane walls in Poiseuille flow at low Reynolds number was developed to study the translational and rotational velocities for a broad range of particle sizes and depths in the channel. Instead of the free-space Green's function more commonly employed in boundary-integral equations, we used the Green's function for the domain between two infinite plane walls [Liron and Mochon, J. Eng. Math. 10, 287 (1976)]. This formulation allows us to directly incorporate the effects of the wall interactions into the stress tensor, without discretizing the bounding walls, and use well-established iterative methods. Our results are in good agreement with previous computations [Ganatos et al., J. Fluid Mech. 99, 755 (1980)] and limiting cases, over their range of application, with additional results obtained for very small particle-wall separations of less than 1% of the particle radius. In addition to the boundary-integral solution in the mobility formulation, we used the resistance formulation to derive the near-field asymptotic forms for the translational and rotational velocities, extending the results to even smaller particle-wall separations. The decrease in translational velocity from the unperturbed fluid velocity increases with particle size and proximity of the particle to one or both of the walls. The rotational velocity exhibits a maximum magnitude between the centerline and either wall, due to the competing influences of wall retardation and the greater fluid velocity gradient near the walls. The average particle velocity for a uniform distribution of particles was generally found to exceed the average fluid velocity, due in large part to exclusion of the particle centers from the region of slowest fluid near the walls. The maximum average particle velocity is 18% greater than the average fluid velocity and occurs for particle diameters that are 42% of the channel height; particles with

  8. The Eigenmode Analysis of Human Motion

    CERN Document Server

    Park, Juyong; Gonzalez, Marta C

    2016-01-01

    Rapid advances in modern communication technology are enabling the accumulation of large-scale, high-resolution observational data of spatiotemporal movements of humans. Classification and prediction of human mobility based on the analysis of such data carry great potential in applications such as urban planning as well as being of theoretical interest. A robust theoretical framework is therefore required to study and properly understand human motion. Here we perform the eigenmode analysis of human motion data gathered from mobile communication records, which allows us to explore the scaling properties and characteristics of human motion.

  9. The eigenmode analysis of human motion

    Science.gov (United States)

    Park, Juyong; Lee, Deok-Sun; González, Marta C.

    2010-11-01

    Rapid advances in modern communication technology are enabling the accumulation of large-scale, high-resolution observational data of the spatiotemporal movements of humans. Classification and prediction of human mobility based on the analysis of such data has great potential in applications such as urban planning in addition to being a subject of theoretical interest. A robust theoretical framework is therefore required to study and properly understand human motion. Here we perform the eigenmode analysis of human motion data gathered from mobile communication records, which allows us to explore the scaling properties and characteristics of human motion.

  10. Application of inertial sensors for motion analysis

    Directory of Open Access Journals (Sweden)

    Ferenc Soha

    2012-06-01

    Full Text Available This paper presents our results on the application of various inertial sensors for motion analysis. After the introduction of different sensor types (accelerometer, gyroscope, magnetic field sensor, we discuss the possible data collection and transfer techniques using embedded signal processing and wireless data communication methods [1,2]. Special consideration is given to the interpretation of accelerometer readings, which contains both the static and dynamic components, and is affected by the orientation and rotation of the sensor. We will demonstrate the possibility to decompose these components for quasiperiodic motions. Finally we will demonstrate the application of commercially available devices (Wii sensor, Kinect sensor, mobile phone for motion analysis applications.

  11. Color structured light system of chest wall motion measurement for respiratory volume evaluation.

    Science.gov (United States)

    Chen, Huijun; Cheng, Yuan; Liu, Dongdong; Zhang, Xiaodong; Zhang, Jue; Que, Chengli; Wang, Guangfa; Fang, Jing

    2010-01-01

    We present a structured light system to dynamically measure human chest wall motion for respiratory volume estimation. Based on a projection of an encoded color pattern and a few active markers attached to the trunk, respiratory volumes are obtained by evaluating the 3-D topographic changes of the chest wall in an anatomically consistent measuring region during respiration. Three measuring setups are established: a single-sided illuminating-recording setup for standing posture, an inclined single-sided setup for supine posture, and a double-sided setup for standing posture. Results are compared with the pneumotachography and show good agreement in volume estimations [correlation coefficient: R>0.99 (Pevaluation with high accuracy, but also regional pulmonary function assessment in different chest wall behaviors, with the advantage of whole-field measurement.

  12. Influence of exchange coupling on current-driven domain wall motion in a nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Komine, Takashi, E-mail: komine@mx.ibaraki.ac.j [Department of Media and Telecommunications Engineering, Ibaraki University, Ibaraki 316-8511 (Japan); Takahashi, Kota; Murakami, Hiroshi; Sugita, Ryuji [Department of Media and Telecommunications Engineering, Ibaraki University, Ibaraki 316-8511 (Japan)

    2010-10-15

    In this study, the effect of exchange stiffness constant on current-driven domain wall motion in nanowires with in-plane magnetic anisotropy (IMA) and perpendicular magnetic anisotropy (PMA) has been investigated using micromagnetic simulation. The critical current density in a nanowire with IMA decreases as the exchange stiffness constant decreases because the domain wall width at the upper edge of the nanowire narrows according to the decrease of the exchange stiffness constant. On the other hand, the critical current density in a nanowire with PMA slightly decreases contrary to that of IMA although the domain wall width reasonably decreases as the exchange stiffness constant decreases. The slight reduction rate of the critical current density is due to the increase of the effective hard-axis anisotropy of PMA nanowire.

  13. Evaluation of regional wall motion in myocardial infarction using animation ECG gated cardiac computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Takahiko; Hyodo, Haruo; Hayashi, Terumi; Yamamoto, Hideo; Yagi, Shigeru

    1984-08-01

    Regional wall motion of the left ventricle was evaluated in 21 patients with myocardial infarction using an animation system of gated cardiac computed tomographic (CT) images (animation gated CCT). The results obtained were compared with data by two-dimensional echocardiography (2-DE). 1. Evaluation of the asynergic area by animation gated CCT and 2-DE: Animation gated CCT detected the following specific regions with asynergy established by 2-DE; 10/10 cases (100%) at the anterior wall of the left ventricle, 14/14 cases (100%) at the interventricular septum, and 9/11 cases (81.8%) at the infero-posterior wall. In addition, one false positive case and one negative case were observed at the lateral wall and the apex, respectively. Of 37 instances with asynergic areas established by 2-DE, 21 cases or 89.2% were detected by animation gated CCT; the sensitivity was 91.9%. 2. Evaluation of severity of asynergy by animation gated CCT and 2-DE: The degree of asynergy evaluated by both methods was compared with each other, and the agreement was as follows: 10/10 cases (100%) at the left-ventricular anterior wall, 13/13 cases (100%) at the interventricular septum, and 7/9 cases (77.8%) at the infero-posterior wall. 3. Evaluation of the asynergic area by nonanimation gated CCT and 2-DE: Nonanimation gated CCT detected asynergic areas ascertained by 2-DE at the following areas; 8/10 cases (80%) at the left-ventricular anterior wall, 12/14 cases (85.7%) at the interventricular septum, and 4/11 cases (36.4%) at the infero-posterior wall. The difference between animation and nonanimation gated CCT was statistically significant (p < 0.05). The severity of asynergy could not be evaluated by nonanimation gated CCT. (J.P.N.).

  14. Lower limb pneumatic compression during dobutamine stress echocardiography in patients with normal resting wall motion: will it increase diagnostic accuracy?

    Science.gov (United States)

    Abdel-Salam, Zainab; Allam, Lawra; Wadie, Bassem; Enany, Bassem; Nammas, Wail

    2015-01-01

    Pneumatic compression of the lower part of the body increases systemic vascular resistance and left ventricular afterload. We compared the diagnostic accuracy of dobutamine stress echocardiography (DSE) with pneumatic compression of the lower extremities, vs. standard DSE, for detection of angiographically significant coronary artery disease (CAD) in patients with normal baseline resting wall motion. We enrolled 70 consecutive patients with no resting wall motion abnormalities (WMA), who underwent DSE. DSE was repeated with pneumatic compression of the lower extremities three days after the initial standard DSE. A positive test was defined as the induction of WMA in at least two contiguous non-overlap segments at any stage of dobutamine infusion. Significant coronary stenosis was defined as ≥ 50% obstruction of ≥ 1 sizable artery by coronary angiography. The mean age of the study cohort was 54.7 ± 9.9 years; 55.7% were females. Thirty-eight (54.3%) patients had significant CAD. The mean test duration was 15.8 ± 5.1 min for standard DSE and 11.7 ± 4.1 min for DSE with pneumatic compression. Analysis of standard DSE revealed sensitivity, specificity, and positive and negative predictive values of 81.6%, 90.6%, 91.2%, and 80.6%, respectively; overall accuracy was 85.7%. Analysis of DSE with pneumatic compression revealed sensitivity, specificity, and positive and negative predictive values of 89.5%, 87.5%, 89.5%, and 87.5%, respectively; overall accuracy was 88.6%. In symptomatic patients with suspected CAD referred for evaluation by DSE, who have no resting wall motion abnormalities, pneumatic compression of the lower extremities during DSE improved the sensitivity but slightly reduced the specificity for detection of angiographically significant CAD, compared with standard DSE. Moreover, it reduced the test duration.

  15. Analysis of Piston Slap Motion

    Directory of Open Access Journals (Sweden)

    Narayan S.

    2015-05-01

    Full Text Available Piston slap is the major force contibuting towards noise levels in combustion engines.This type of noise depends upon a number of factors such as the piston-liner gap, type of lubricant used, number of piston pins as well as geometry of the piston. In this work the lateral and rotary motion of the piston in the gap between the cylinder liner and piston has been analyzed. A model that can predict the forces and response of the engine block due to slap has been dicussed. The parameters such as mass, spring and damping constant have been predicted using a vibrational mobility model.

  16. Analysis of Piston Slap Motion

    Science.gov (United States)

    Narayan, S.

    2015-05-01

    Piston slap is the major force contibuting towards noise levels in combustion engines.This type of noise depends upon a number of factors such as the piston-liner gap, type of lubricant used, number of piston pins as well as geometry of the piston. In this work the lateral and rotary motion of the piston in the gap between the cylinder liner and piston has been analyzed. A model that can predict the forces and response of the engine block due to slap has been dicussed. The parameters such as mass, spring and damping constant have been predicted using a vibrational mobility model.

  17. A dynamic human motion: coordination analysis.

    Science.gov (United States)

    Pchelkin, Stepan; Shiriaev, Anton S; Freidovich, Leonid B; Mettin, Uwe; Gusev, Sergei V; Kwon, Woong; Paramonov, Leonid

    2015-02-01

    This article is concerned with the generic structure of the motion coordination system resulting from the application of the method of virtual holonomic constraints (VHCs) to the problem of the generation and robust execution of a dynamic humanlike motion by a humanoid robot. The motion coordination developed using VHCs is based on a motion generator equation, which is a scalar nonlinear differential equation of second order. It can be considered equivalent in function to a central pattern generator in living organisms. The relative time evolution of the degrees of freedom of a humanoid robot during a typical motion are specified by a set of coordination functions that uniquely define the overall pattern of the motion. This is comparable to a hypothesis on the existence of motion patterns in biomechanics. A robust control is derived based on a transverse linearization along the configuration manifold defined by the coordination functions. It is shown that the derived coordination and control architecture possesses excellent robustness properties. The analysis is performed on an example of a real human motion recorded in test experiments.

  18. LCD motion blur: modeling, analysis, and algorithm.

    Science.gov (United States)

    Chan, Stanley H; Nguyen, Truong Q

    2011-08-01

    Liquid crystal display (LCD) devices are well known for their slow responses due to the physical limitations of liquid crystals. Therefore, fast moving objects in a scene are often perceived as blurred. This effect is known as the LCD motion blur. In order to reduce LCD motion blur, an accurate LCD model and an efficient deblurring algorithm are needed. However, existing LCD motion blur models are insufficient to reflect the limitation of human-eye-tracking system. Also, the spatiotemporal equivalence in LCD motion blur models has not been proven directly in the discrete 2-D spatial domain, although it is widely used. There are three main contributions of this paper: modeling, analysis, and algorithm. First, a comprehensive LCD motion blur model is presented, in which human-eye-tracking limits are taken into consideration. Second, a complete analysis of spatiotemporal equivalence is provided and verified using real video sequences. Third, an LCD motion blur reduction algorithm is proposed. The proposed algorithm solves an l(1)-norm regularized least-squares minimization problem using a subgradient projection method. Numerical results show that the proposed algorithm gives higher peak SNR, lower temporal error, and lower spatial error than motion-compensated inverse filtering and Lucy-Richardson deconvolution algorithm, which are two state-of-the-art LCD deblurring algorithms.

  19. Unstable equilibrium point in chaotic domain-wall motion and Ott{endash}Grebogi{endash}Yorke control

    Energy Technology Data Exchange (ETDEWEB)

    Okuno, H.; Takemura, Y.

    2001-06-01

    A method for finding the unstable equilibrium points in Bloch wall motion is proposed, which is important for controlling the chaotic domain-wall motion by using the Ott{endash}Grebogi{endash}Yorke (OGY) method. The dynamics of Bloch wall motion are expressed by a nonlinear differential equation with the terms of inertia, damping, restoring, and an external magnetic drive force. An equation is transformed into the difference equations by following the OGY method, approximating linearly around an unstable equilibrium point (a saddle point), and adding a controlling input. The unstable equilibrium points are obtained by using the return map and the condition of hyperbolic fixed point. The time series of domain-wall motion successfully controlled on the unstable equilibrium points by the OGY method is shown. {copyright} 2001 American Institute of Physics.

  20. 3D motion analysis via energy minimization

    Energy Technology Data Exchange (ETDEWEB)

    Wedel, Andreas

    2009-10-16

    This work deals with 3D motion analysis from stereo image sequences for driver assistance systems. It consists of two parts: the estimation of motion from the image data and the segmentation of moving objects in the input images. The content can be summarized with the technical term machine visual kinesthesia, the sensation or perception and cognition of motion. In the first three chapters, the importance of motion information is discussed for driver assistance systems, for machine vision in general, and for the estimation of ego motion. The next two chapters delineate on motion perception, analyzing the apparent movement of pixels in image sequences for both a monocular and binocular camera setup. Then, the obtained motion information is used to segment moving objects in the input video. Thus, one can clearly identify the thread from analyzing the input images to describing the input images by means of stationary and moving objects. Finally, I present possibilities for future applications based on the contents of this thesis. Previous work in each case is presented in the respective chapters. Although the overarching issue of motion estimation from image sequences is related to practice, there is nothing as practical as a good theory (Kurt Lewin). Several problems in computer vision are formulated as intricate energy minimization problems. In this thesis, motion analysis in image sequences is thoroughly investigated, showing that splitting an original complex problem into simplified sub-problems yields improved accuracy, increased robustness, and a clear and accessible approach to state-of-the-art motion estimation techniques. In Chapter 4, optical flow is considered. Optical flow is commonly estimated by minimizing the combined energy, consisting of a data term and a smoothness term. These two parts are decoupled, yielding a novel and iterative approach to optical flow. The derived Refinement Optical Flow framework is a clear and straight-forward approach to

  1. Magnetic domain-wall motion twisted by nanoscale probe-induced spin transfer

    Science.gov (United States)

    Wang, J.; Xie, L. S.; Wang, C. S.; Zhang, H. Z.; Shu, L.; Bai, J.; Chai, Y. S.; Zhao, X.; Nie, J. C.; Cao, C. B.; Gu, C. Z.; Xiong, C. M.; Sun, Y.; Shi, J.; Salahuddin, S.; Xia, K.; Nan, C. W.; Zhang, J. X.

    2014-12-01

    A method for deterministic control of magnetism using an electrical stimulus is highly desired for the new generation of magnetoelectronic devices. Much effort has been focused on magnetic domain-wall (DW) motion manipulated by a successive injection of spin-polarized current into a magnetic nanostructure. However, an integrant high-threshold current density of 1011˜1012A /m2 inhibits the integration with low-energy-cost technology. Here, we report an approach to manipulate a single magnetic domain wall with a perpendicular anisotropy in a manganite/dielectric/metal capacitor using a probe-induced spin displacement. A spin-transfer torque (STT) occurs in the strongly correlated manganite film during the spin injection into the capacitor from the nanoscale magnetized tip with an ultralow voltage of 0.1 V, where a lower bound of the estimated threshold spin-polarized current density is ˜108A /m2 at the tip/manganite interface. The dynamic of DW motions are analyzed using the Landau-Lifshitz-Gilbert method. This probe-voltage-controlled DW motion, at an ambient condition, demonstrates a critical framework for the fundamental understanding of the manipulation of the nanomagnet systems with low-energy consumption.

  2. Assessment of left ventricular wall motion abnormalities with the use of color kinesis: a valuable visual and training aid.

    Science.gov (United States)

    Lau, Y S; Puryear, J V; Gan, S C; Fowler, M B; Vagelos, R H; Popp, R L; Schnittger, I

    1997-01-01

    Accurate interpretation of left ventricular segmental wall motion by echocardiography is an important yet difficult skill to learn. Color-coded left ventricular wall motion (color kinesis) is a tool that potentially could aid in the interpretation and provide semiquantification. We studied the usefulness of color kinesis in 42 patients with a history of congestive cardiomyopathy who underwent two-dimensional echocardiograms and a color kinesis study. The expert's reading of the two-dimensional wall motion served as a reference for comparison of color kinesis studies interpreted by the expert and a cardiovascular trainee. Correlation between two-dimensional echocardiography and the expert's and trainee's color coded wall motion scores were r = 0.83 and r = 0.67, respectively. Reproducibility between reviewers and between operators was also assessed. Interobserver variability for color-coded wall motion showed a correlation of r = 0.78. Correlation between operators was also good; r = 0.84. Color kinesis is reliable and appears promising as an adjunct in the assessment of wall motion abnormalities by echocardiography. It is both a valuable visual aid, as well as a training aid for the cardiovascular trainee.

  3. Temperature dependence of carrier spin polarization determined from current-induced domain wall motion in a Co/Ni nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, K.; Koyama, T.; Hiramatsu, R.; Kobayashi, K.; Ono, T. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Chiba, D. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 322-0012 (Japan); Fukami, S. [Green Innovation Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba, Ibaraki 305-8501 (Japan); Center for Spintronics Integrated Systems, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Tanigawa, H.; Suzuki, T. [RENESAS Electronics Corporation, Sagamihara, Kanagawa 252-5298 (Japan); Ohshima, N. [NEC Energy Device Ltd., 1120 Shimokuzawa, Chuo-ku, Sagamihara, Kanagawa 252-5298 (Japan); Ishiwata, N. [Green Innovation Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba, Ibaraki 305-8501 (Japan); Nakatani, Y. [University of Electro-communications, Chofu, Tokyo 182-8585 (Japan)

    2012-05-14

    We have investigated the temperature dependence of the current-induced magnetic domain wall (DW) motion in a perpendicularly magnetized Co/Ni nanowire at various temperatures and with various applied currents. The carrier spin polarization was estimated from the measured domain wall velocity. We found that it decreased more with increasing temperature from 100 K to 530 K than the saturation magnetization did.

  4. Mending Wall: A Rhetorical Analysis

    Institute of Scientific and Technical Information of China (English)

    戚婕

    2009-01-01

    From this poem, we can see some of Frost's poetic language style and one of his themes: the relationship between humans. This paper is an attempt to reveal Frost's style of simple beauty through rhetoric analysis. The poet uses simple rhetorical devices like metaphor, simile, and repetition to convey much profound implication and provoke thinking. Rhetoric devices partly illustrate Frost's genius in making his poems simple in language but profound in idea.

  5. Solution of Two-Dimensional Viscous Flow Driven by Motion of Flexible Walls

    Directory of Open Access Journals (Sweden)

    Mohamed Gad-el-Hak

    2010-03-01

    Full Text Available An exact solution of the Navier–Stokes equations for a flow driven by motion of flexible wall is developed. A simple two-dimensional channel with deforming walls is considered as domain. The governing equations are linearized for low Reynolds number and large Womersley number Newtonian flows. Appropriate boundary conditions for general deformation are decomposed into harmonic excitations in space by Fourier series decomposition. A model of harmonic boundary deformation is considered and results are compared with computational fluid dynamics predictions. The results of velocity profiles across the channel and the centerline velocities of the channel are in good agreement with CFD solution. The analytical model developed provides quantitative descriptions of the flow field for a wide spectrum of actuating frequnecy and boundary conditions. The presented model can be used as an effective framework for preliminary design and optimization of displacement micropumps and other miniature applications.

  6. Influence of wall motion on particle sedimentation using hybrid LB-IBM scheme

    Science.gov (United States)

    Habte, Mussie A.; Wu, ChuiJie

    2017-03-01

    We integrate the lattice Boltzmann method (LBM) and immersed boundary method (IBM) to capture the coupling between a rigid boundary surface and the hydrodynamic response of an enclosed particle laden fluid. We focus on a rigid box filled with a Newtonian fluid where the drag force based on the slip velocity at the wall and settling particles induces the interaction. We impose an external harmonic oscillation on the system boundary and found interesting results in the sedimentation behavior. Our results reveal that the sedimentation and particle locations are sensitive to the boundary walls oscillation amplitude and the subsequent changes on the enclosed flow field. Two different particle distribution analyses were performed and showed the presence of an agglomerate structure of particles. Despite the increase in the amplitude of wall motion, the turbulence level of the flow field and distribution of particles are found to be less in quantity compared to the stationary walls. The integrated LBM-IBM methodology promised the prospect of an efficient and accurate dynamic coupling between a non-compliant bounding surface and flow field in a wide-range of systems. Understanding the dynamics of the fluid-filled box can be particularly important in a simulation of particle deposition within biological systems and other engineering applications.

  7. Two-dimensional simulation of red blood cell motion near a wall under a lateral force

    Science.gov (United States)

    Hariprasad, Daniel S.; Secomb, Timothy W.

    2014-11-01

    The motion of a red blood cell suspended in a linear shear flow adjacent to a fixed boundary subject to an applied lateral force directed toward the boundary is simulated. A two-dimensional model is used that represents the viscous and elastic properties of normal red blood cells. Shear rates in the range of 100 to 600 s-1 are considered, and the suspending medium viscosity is 1 cP. In the absence of a lateral force, the cell executes a tumbling motion. With increasing lateral force, a transition from tumbling to tank-treading is predicted. The minimum force required to ensure tank-treading increases nonlinearly with the shear rate. Transient swinging motions occur when the force is slightly larger than the transition value. The applied lateral force is balanced by a hydrodynamic lift force resulting from the positive orientation of the long axis of the cell with respect to the wall. In the case of cyclic tumbling motions, the orientation angle takes positive values through most of the cycle, resulting in lift generation. These results are used to predict the motion of a cell close to the outer edge of the cell-rich core region that is generated when blood flows in a narrow tube. In this case, the lateral force is generated by shear-induced dispersion, resulting from cell-cell interactions in a region with a concentration gradient. This force is estimated using previous data on shear-induced dispersion. The cell is predicted to execute tank-treading motions at normal physiological hematocrit levels, with the possibility of tumbling at lower hematocrit levels.

  8. Energy-efficient writing scheme for magnetic domain-wall motion memory

    Science.gov (United States)

    Kim, Kab-Jin; Yoshimura, Yoko; Ham, Woo Seung; Ernst, Rick; Hirata, Yuushou; Li, Tian; Kim, Sanghoon; Moriyama, Takahiro; Nakatani, Yoshinobu; Ono, Teruo

    2017-04-01

    We present an energy-efficient magnetic domain-writing scheme for domain wall (DW) motion-based memory devices. A cross-shaped nanowire is employed to inject a domain into the nanowire through current-induced DW propagation. The energy required for injecting the magnetic domain is more than one order of magnitude lower than that for the conventional field-based writing scheme. The proposed scheme is beneficial for device miniaturization because the threshold current for DW propagation scales with the device size, which cannot be achieved in the conventional field-based technique.

  9. Analysis of flat slab building with and without shear wall

    Directory of Open Access Journals (Sweden)

    Dhanaji R. Chavan

    2016-10-01

    Full Text Available The analytical research carried out to study the behaviour flat slab building with and without shear wall reported in the present work. For analysis 15 storied flat slab building is analyzed for seismic behaviour. Response spectrum method is used for analysis considering different shear wall positions using ETABS software. Five different positions of shear wall were studied for analysis. From this analysis shear wall at core having square shape is most suitable case for construction of shear wall.

  10. Assessment of myocardial segmental function with coronary artery stenosis in multi-vessel coronary disease patients with normal wall motion.

    Science.gov (United States)

    Xie, M-Y; Lv, Q; Wang, J; Yin, J-B

    2016-04-01

    To discover the impact of the various degrees of coronary artery stenosis (CAD) on the left ventricular systolic dysfunction in steady state with quantitative analysis of the regional systolic myocardium in longitudinal, radial and circumferential direction in patients with coronary artery disease by two-dimensional speckle tracking imaging (STI). Forty-three normal wall motion-multi vessel coronary artery disease (NWM-MVD) patients labeled as the experimental groups and forty-two subjects with little risk of CAD marked as the control group were enrolled in this study. The two-dimensional STI was obtained in the apical long axis and three levels of the short axis of the left ventricle. The left ventricular wall was divided into 18 segments. The affected myocardia were divided into three groups: group B (coronary stenosis degree ≤50%), group C (coronary stenosis degree 50%-99%)and group D (coronary stenosis degree ≥99%). Using the Q-analysis software, the longitudinal, radial and circumferential systolic strain (SL, SR, SC) and strain ratio (SrL, SrR, SrC) of the myocardium were analyzed. The bradycardia in the NWM-MVD group is greater than that in the control group (16/43 vs. 7/42, p coronary stenosis degree ≤50%), group C (coronary stenosis degree 50%-99%)and group D (coronary stenosis degree ≥99%), especially the longitudinal and radial systolic function, even though they had normal wall motion. The SrL equaled 1.085 for the cut-off value, and the sums (1.348) of sensitivity (0.673) and specificity (0.675) were the greatest. Bradycardia might be a compensatory mechanism in NWM-MVD patients.

  11. Effect of Joule heating in current-driven domain wall motion

    Science.gov (United States)

    Yamaguchi, A.; Nasu, S.; Tanigawa, H.; Ono, T.; Miyake, K.; Mibu, K.; Shinjo, T.

    2005-01-01

    It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed current. The sample temperature was 750 K for the threshold current density of 6.7×1011A/m2 in a 10-nm-thick Ni81Fe19 wire with a width of 240 nm on thermally oxidized silicon substrate. The temperature was raised to 830 K for the current density of 7.5×1011A/m2, which is very close to the Curie temperature of bulk Ni81Fe19. When the current density exceeded 7.5×1011A/m2, an appearance of a multidomain structure in the wire was observed by magnetic force microscopy, suggesting that the sample temperature exceeded the Curie temperature.

  12. Observation of hohlraum-wall motion with spectrally selective x-ray imaging at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, N., E-mail: izumi2@llnl.gov; Meezan, N. B.; Divol, L.; Hall, G. N.; Barrios, M. A.; Jones, O.; Landen, O. L.; Kroll, J. J.; Vonhof, S. A.; Nikroo, A.; Bailey, C. G.; Hardy, C. M.; Ehrlich, R. B.; Town, R. P. J.; Bradley, D. K.; Hinkel, D. E.; Moody, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Jaquez, J. [General Atomics, San Diego, California 9212 (United States)

    2016-11-15

    The high fuel capsule compression required for indirect drive inertial confinement fusion requires careful control of the X-ray drive symmetry throughout the laser pulse. When the outer cone beams strike the hohlraum wall, the plasma ablated off the hohlraum wall expands into the hohlraum and can alter both the outer and inner cone beam propagations and hence the X-ray drive symmetry especially at the final stage of the drive pulse. To quantitatively understand the wall motion, we developed a new experimental technique which visualizes the expansion and stagnation of the hohlraum wall plasma. Details of the experiment and the technique of spectrally selective x-ray imaging are discussed.

  13. Observation of hohlraum-wall motion with spectrally selective x-ray imaging at the National Ignition Facility

    Science.gov (United States)

    Izumi, N.; Meezan, N. B.; Divol, L.; Hall, G. N.; Barrios, M. A.; Jones, O.; Landen, O. L.; Kroll, J. J.; Vonhof, S. A.; Nikroo, A.; Jaquez, J.; Bailey, C. G.; Hardy, C. M.; Ehrlich, R. B.; Town, R. P. J.; Bradley, D. K.; Hinkel, D. E.; Moody, J. D.

    2016-11-01

    The high fuel capsule compression required for indirect drive inertial confinement fusion requires careful control of the X-ray drive symmetry throughout the laser pulse. When the outer cone beams strike the hohlraum wall, the plasma ablated off the hohlraum wall expands into the hohlraum and can alter both the outer and inner cone beam propagations and hence the X-ray drive symmetry especially at the final stage of the drive pulse. To quantitatively understand the wall motion, we developed a new experimental technique which visualizes the expansion and stagnation of the hohlraum wall plasma. Details of the experiment and the technique of spectrally selective x-ray imaging are discussed.

  14. Role of spin diffusion in current-induced domain wall motion for disordered ferromagnets

    KAUST Repository

    Akosa, Collins Ashu

    2015-03-12

    Current-induced spin transfer torque and magnetization dynamics in the presence of spin diffusion in disordered magnetic textures is studied theoretically. We demonstrate using tight-binding calculations that weak, spin-conserving impurity scattering dramatically enhances the nonadiabaticity. To further explore this mechanism, a phenomenological drift-diffusion model for incoherent spin transport is investigated. We show that incoherent spin diffusion indeed produces an additional spatially dependent torque of the form ∼∇2[m×(u⋅∇)m]+ξ∇2[(u⋅∇)m], where m is the local magnetization direction, u is the direction of injected current, and ξ is a parameter characterizing the spin dynamics (precession, dephasing, and spin-flip). This torque, which scales as the inverse square of the domain wall width, only weakly enhances the longitudinal velocity of a transverse domain wall but significantly enhances the transverse velocity of vortex walls. The spatial-dependent spin transfer torque uncovered in this study is expected to have significant impact on the current-driven motion of abrupt two-dimensional textures such as vortices, skyrmions, and merons.

  15. Effect of microwaves on domain wall motion in thin Ni wires

    Science.gov (United States)

    Hong, Kimin; Giordano, N.

    1996-03-01

    We report new results on domain wall motion in thin (width and thickness ~ 300 ÅNi wires. The magnetoresistance exhibits discontinuities which we believe are associated with pinning and de-pinning of walls from structural defects, such as variations in the width of the sample. Upon repeated measurement, the de-pinning is found to occur over a narrow range of fields. The distribution of de-pinning fields, P(H), varies with temperature in a manner which suggests that de-pinning occurs via thermal activation at high temperatures, and quantum tunneling at low temperatures, with crossover between these two regimes at T ~ 2 - 6 K. We have also investigated the effect of a 30 GHz microwave field on P(H). In the thermal activation regime, microwaves have no effect on P(H), except through Joule heating. However, in the tunneling regime microwaves cause P(H) to split into several separate peaks. This behavior cannot be explained in terms of Joule heating, but suggests that the energy levels of a domain wall in a pinning well are quantized.

  16. In-vivo quantification of wall motion in cerebral aneurysms from 2D cine phase contrast magnetic resonance images

    Energy Technology Data Exchange (ETDEWEB)

    Karmonik, C. [The Methodist Hospital Research Inst., Houston (United States); Diaz, O.; Klucznik, R. [The Methodist Hospital, Houston (United States); Grossman, R. [The Methodist Hospital, Houston (United States). Neurosurgery

    2010-02-15

    Purpose: The quantification of wall motion in cerebral aneurysms is of interest for the assessment of aneurysmal rupture risk, for providing boundary conditions for computational simulations and as a validation tool for theoretical models. Materials and Methods: 2D cine phase contrast magnetic resonance imaging (2D pcMRI) in combination with quantitative magnetic resonance angiography (QMRA) was evaluated for measuring wall motion in 7 intracranial aneurysms. In each aneurysm, 2 (in one case 3) cross sections, oriented approximately perpendicular to each other, were measured. Results: The maximum aneurysmal wall distention ranged from 0.16 mm to 1.6 mm (mean 0.67 mm), the maximum aneurysmal wall contraction was -1.91 mm to -0.34 mm (mean 0.94 mm), and the average wall displacement ranged from 0.04 mm to 0.31 mm (mean 0.15 mm). Statistically significant correlations between average wall displacement and the shape of inflow curves (p-value < 0.05) were found in 7 of 15 cross sections; statistically significant correlations between the displacement of the luminal boundary center point and the shape of inflow curves (p-value < 0.05) were found in 6 of 15 cross sections. Conclusion: 2D pcMRI in combination with QMRA is capable of visualizing and quantifying wall motion in cerebral aneurysms. However, application of this technique is currently restricted by its limited spatial resolution. (orig.)

  17. Roles of the magnetic field and electric current in thermally activated domain wall motion in a submicrometer magnetic strip with perpendicular magnetic anisotropy.

    Science.gov (United States)

    Emori, Satoru; Beach, Geoffrey S D

    2012-01-18

    We have experimentally studied micrometer-scale domain wall (DW) motion driven by a magnetic field and an electric current in a Co/Pt multilayer strip with perpendicular magnetic anisotropy. The thermal activation energy for DW motion, along with its scaling with the driving field and current, has been extracted directly from the temperature dependence of the DW velocity. The injection of DC current resulted in an enhancement of the DW velocity independent of the current polarity, but produced no measurable change in the activation energy barrier. Through this analysis, the observed current-induced DW velocity enhancement can be entirely and unambiguously attributed to Joule heating.

  18. Micromagnetic modeling of domain wall motion in sub-100-nm-wide wires with individual and periodic edge defects

    Directory of Open Access Journals (Sweden)

    S. Dutta

    2015-12-01

    Full Text Available Reducing the switching energy of devices that rely on magnetic domain wall motion requires scaling the devices to widths well below 100 nm, where the nanowire line edge roughness (LER is an inherent source of domain wall pinning. We investigate the effects of periodic and isolated rectangular notches, triangular notches, changes in anisotropy, and roughness measured from images of fabricated wires, in sub-100-nm-wide nanowires with in-plane and perpendicular magnetic anisotropy using micromagnetic modeling. Pinning fields calculated for a model based on discretized images of physical wires are compared to experimental measurements. When the width of the domain wall is smaller than the notch period, the domain wall velocity is modulated as the domain wall propagates along the wire. We find that in sub-30-nm-wide wires, edge defects determine the operating threshold and domain wall dynamics.

  19. The contribution of 180° domain wall motion to dielectric properties quantified from in situ X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Fancher, C.M.; Brewer, S.; Chung, C.C.; Röhrig, S.; Rojac, T.; Estevesa, G.; Deluca, M.; Bassiri-Gharb, N.; Jones, J.L. (Mat. Cent. Leoben); (NCSU); (Joseph Stefan Inst.); (GIT)

    2017-03-01

    The contribution of 180° domain wall motion to polarization and dielectric properties of ferroelectric materials has yet to be determined experimentally. In this paper, an approach for estimating the extent of (180°) domain reversal during application of electric fields is presented. We demonstrate this method by determining the contribution of domain reversal to polarization in soft lead zirconate titanate during application of strong electric fields. At the maximum applied field, domain reversal was determined to account for >80% of the measured macroscopic polarization. We also apply the method to quantify the contribution of domain reversal to the weak-field dielectric permittivity of BaTiO3. The results of this analysis determined that domain reversal accounts for up to ~70% of the macroscopic dielectric permittivity in BaTiO3. These results demonstrate the predominance of domain reversal to high and low-field dielectric response in ferroelectric polycrystalline materials.

  20. Analysis of flat slab building with and without shear wall

    OpenAIRE

    Dhanaji R. Chavan; Mohite D. D.; Dr. C. P. Pise; Pawar Y. P; Kadam S.S.; Deshmukh C. M.

    2016-01-01

    The analytical research carried out to study the behaviour flat slab building with and without shear wall reported in the present work. For analysis 15 storied flat slab building is analyzed for seismic behaviour. Response spectrum method is used for analysis considering different shear wall positions using ETABS software. Five different positions of shear wall were studied for analysis. From this analysis shear wall at core having square shape is most suitable case for construction of shear ...

  1. Easy moment direction and antiferromagnetic domain wall motion in Mn2Au

    Science.gov (United States)

    Barthem, Vitoria M. T. S.; Colin, Claire V.; Haettel, Richard; Dufeu, Didier; Givord, Dominique

    2016-05-01

    The interest of giving active functions to antiferromagnetic (AFM) materials in spintronics devices has been realized recently. Mn2Au is a high-Néel temperature antiferromagnet with large Mn moment, lying in plane of the tetragonal structure. To determine the direction of the moments in Mn2Au, an original approach is demonstrated, which should be generic to planar AFM materials. It involves the rotation of the granular sample around an axis perpendicular to the applied magnetic field. The family of easy moment directions is . For grains prevented from rotating, the dominant magnetization process is AFM domain wall motion. Textured Mn2Au nanoelements could be introduced in spintronics devices, in which the Mn moments would be switched under modest external excitation.

  2. Miniature Hall sensor integrated on a magnetic thin film for detecting domain wall motion

    Science.gov (United States)

    Kubota, M.; Tokunaga, Y.; Kanazawa, N.; Kagawa, F.; Tokura, Y.; Kawasaki, M.

    2013-08-01

    We have fabricated a cross-bar Hall sensor made of 50-nm-wide and 100-nm-thick bismuth wires patterned by an electron-beam lithography and lift-off. The Hall coefficient at 300 K is as large as -0.44 cm3/C, yielding in a high product sensitivity of about 5 V/(A T). The series resistance was reduced as low as 1.7 kΩ with a short bar configuration, resulting in a high signal-to-noise ratio of 38.5 dB. These characteristics are far better than those reported with similar dimensions. The Hall element was successfully demonstrated for detecting the domain wall motion in an iron garnet film employed as the substrate.

  3. Ring-shaped Racetrack memory based on spin orbit torque driven chiral domain wall motions

    Science.gov (United States)

    Zhang, Yue; Zhang, Xueying; Hu, Jingtong; Nan, Jiang; Zheng, Zhenyi; Zhang, Zhizhong; Zhang, Youguang; Vernier, Nicolas; Ravelosona, Dafine; Zhao, Weisheng

    2016-10-01

    Racetrack memory (RM) has sparked enormous interest thanks to its outstanding potential for low-power, high-density and high-speed data storage. However, since it requires bi-directional domain wall (DW) shifting process for outputting data, the mainstream stripe-shaped concept certainly suffers from the data overflow issue. This geometrical restriction leads to increasing complexity of peripheral circuits or programming as well as undesirable reliability issue. In this work, we propose and study ring-shaped RM, which is based on an alternative mechanism, spin orbit torque (SOT) driven chiral DW motions. Micromagnetic simulations have been carried out to validate its functionality and exhibit its performance advantages. The current flowing through the heavy metal instead of ferromagnetic layer realizes the “end to end” circulation of storage data, which remains all the data in the device even if they are shifted. It blazes a promising path for application of RM in practical memory and logic.

  4. Apical regional wall motion abnormalities reminiscent to Tako-Tsubo cardiomyopathy following consumption of psychoactive fungi.

    Science.gov (United States)

    Nef, Holger M; Möllmann, Helge; Hilpert, Pirmin; Krause, Nicola; Troidl, Christian; Weber, Michael; Rolf, Andreas; Dill, Thorsten; Hamm, Christian; Elsässer, A

    2009-05-01

    Consumption of natural hallucinogenic substances continues to be a problem. In this case we report from a young male patient presenting with an acute coronary syndrome with significant ST-elevation after the abuse of psychoactive fungi, commonly referred to as "magic mushrooms". Coronary angiography excludes relevant coronary artery disease. In ventriculography contractile dysfunction with hypokinesia in the apical segments could be documented reminiscent to wall motion abnormalities in Tako-Tsubo cardiomyopathy (TTC). Cardiovascular magnetic resonance imaging showed no pathological signal activity in the late-enhancement sequences ruling out myocardial infarction or inflammatory processes. Ventricular function normalized within several days. The active metabolite of psychoactive fungi psilocybin is known to interact with several different dopaminergic, adrenergic and serotonergic receptors. Thus, the pathomechanisms leading to contractile dysfunction after consumption of psychoactive fungi are reminiscent to those documented in TTC.

  5. Easy moment direction and antiferromagnetic domain wall motion in Mn{sub 2}Au

    Energy Technology Data Exchange (ETDEWEB)

    Barthem, Vitoria M.T.S. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21941-972 Rio de Janeiro (Brazil); Colin, Claire V.; Haettel, Richard; Dufeu, Didier [Université Grenoble Alpes, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France); CNRS, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France); Givord, Dominique, E-mail: dominique.givord@neel.cnrs.fr [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21941-972 Rio de Janeiro (Brazil); Université Grenoble Alpes, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France); CNRS, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France)

    2016-05-15

    The interest of giving active functions to antiferromagnetic (AFM) materials in spintronics devices has been realized recently. Mn{sub 2}Au is a high-Néel temperature antiferromagnet with large Mn moment, lying in plane of the tetragonal structure. To determine the direction of the moments in Mn{sub 2}Au, an original approach is demonstrated, which should be generic to planar AFM materials. It involves the rotation of the granular sample around an axis perpendicular to the applied magnetic field. The family of easy moment directions is 〈110〉. For grains prevented from rotating, the dominant magnetization process is AFM domain wall motion. Textured Mn{sub 2}Au nanoelements could be introduced in spintronics devices, in which the Mn moments would be switched under modest external excitation.

  6. Magnetic domain wall motion in Co/Ni nanowires induced by a sloped electric field

    Science.gov (United States)

    Yamada, Keisuke; Murayama, Soh; Nakatani, Yoshinobu

    2016-05-01

    We report the sloped-electric-field (SEF)-driven motion of a magnetic domain wall (DW) in a Co/Ni nanowire with a perpendicular anisotropy using micromagnetic simulations. The results show that the DW velocity increases in proportion to the modulation ratio of the SEF, and rapidly decreases above a threshold ratio of SEF (i.e., the breakdown). We derived the analytical equation of the effective magnetic field caused by the SEF, and show the resultant DW velocity. Also, we found that the maximum DW velocity is three times faster when the Dzyaloshinskii-Moriya interaction is 0.06 erg/cm2. The results presented here offer a promising route for the design of non-volatile memory and logic devices using only the electric-field.

  7. Transient motion of and heat transfer in a rarefied gas between plane parallel walls with different surface properties

    Science.gov (United States)

    Doi, Toshiyuki

    2016-09-01

    Transient motion of and heat transfer in a rarefied gas between plane parallel walls with different surface properties are studied based on kinetic theory. It is assumed that one wall is a diffuse reflection boundary and the other wall is a Maxwell-type boundary, and the transient behavior of the gas caused by a sudden heating of one of the walls is studied. The linearized Boltzmann equation for a hard-sphere molecular gas is numerically studied using the modified hybrid scheme of the characteristic coordinate and finite difference methods, to correctly describe the discontinuities in the velocity distribution function. The transient motion of the gas from an early time stage to the final time-independent state is studied over a wide range of the mean free path and the accommodation coefficient of the boundary. Between the two transient flows caused by the heating of the respective walls, the values of the heat flow on the heated wall are different, whereas those on the unheated wall coincide identically. This property, which is a consequence of the symmetric relation of the linearized Boltzmann equation, is numerically confirmed over a wide range of the mean free path. The long time behavior of the heat flow on the walls is quite similar to that of the shear stress in the Couette flow problem, whereas a distinct wavy behavior is observed in an early time stage.

  8. Simulation study of passive target motion analysis

    Institute of Scientific and Technical Information of China (English)

    HU Youfeng; JIAO Binli

    2003-01-01

    In this paper, the problem of underwater passive target motion analysis (TMA) in three dimensions is discussed using the measurements of passive bearings and elevation and frequency on the condition that acoustic source and observer are in different horizontal planes. Simulation results with both of the PLE (pseudo-linear estimation) and MLE (Maximum likelihood estimation) show that the TMA method is effective in oceanic environment. Its error covariance curves tend to its Cramer-Rao lower bounds.

  9. Direct observation of current-induced motion of a 3D vortex domain wall in cylindrical nanowires

    KAUST Repository

    Ivanov, Yurii P.

    2017-05-08

    The current-induced dynamics of 3D magnetic vortex domain walls in cylindrical Co/Ni nanowires are revealed experimentally using Lorentz microscopy and theoretically using micromagnetic simulations. We demonstrate that a spin-polarized electric current can control the reversible motion of 3D vortex domain walls, which travel with a velocity of a few hundred meters per second. This finding is a key step in establishing fast, high-density memory devices based on vertical arrays of cylindrical magnetic nanowires.

  10. Steady motion of skyrmions and domains walls under diffusive spin torques

    KAUST Repository

    Elías, Ricardo Gabriel

    2017-03-09

    We explore the role of the spin diffusion of conducting electrons in two-dimensional magnetic textures (domain walls and skyrmions) with spatial variation of the order of the spin precession length λex. The effect of diffusion reflects in four additional torques that are third order in spatial derivatives of magnetization and bilinear in λex and in the nonadiabatic parameter β′. In order to study the dynamics of the solitons when these diffusive torques are present, we derive the Thiele equation in the limit of steady motion and we compare the results with the nondiffusive limit. When considering a homogenous current these torques increase the longitudinal velocity of transverse domain walls of width Δ by a factor (λex/Δ)2(α/3), α being the magnetic damping constant. In the case of single skyrmions with core radius r0 these new contributions tend to increase the Magnus effect in an amount proportional to (λex/r0)2(1+2αβ′).

  11. Vagal control of cardiac electrical activity and wall motion during ventricular fibrillation in large animals.

    Science.gov (United States)

    Naggar, Isaac; Nakase, Ko; Lazar, Jason; Salciccioli, Louis; Selesnick, Ivan; Stewart, Mark

    2014-07-01

    Vagal inputs control pacemaking and conduction systems in the heart. Anatomical evidence suggests a direct ventricular action, but functional evidence that separates direct and indirect (via the conduction system) vagal actions is less well established. We studied vagus nerve stimulation (VNS) during sinus rhythm and ventricular fibrillation (VF) in pigs and sheep to determine: 1) the range of unilateral and bilateral actions (inotropic and chronotropic) and 2) whether VNS alters left ventricular motion and/or electrical activity during VF, a model of abnormal electrical conduction of the left ventricle that excludes sinus and atrioventricular nodal function. Adult pigs (N=8) and sheep (N=10) were anesthetized with urethane and mechanically ventilated. VNS was performed in animals at 1, 2, 5, 10, 20, 50, and 100Hz for 20s. VF was induced with direct current to the ventricles or occlusion of the left anterior descending coronary artery. In 4 pigs and 3 sheep, left ventricular wall motion was assessed from endocardial excursion in epicardial echocardiography. In sheep and pigs, the best frequency among those tested for VNS during sinus rhythm to produce sustained electrical and mechanical ventricular standstill was 50Hz for unilateral or bilateral stimulation. When applied during VF, bilateral VNS increased the variability of the dominant VF frequency, indicating a direct impact on the excitability of ventricular myocytes, and decreased endocardial excursion by more than 50% during VF. We conclude that the vagus nerve directly modulates left ventricular function independently from its effects on the conduction system.

  12. Shear-Resistant Behavior Analysis of Light Composite Shear Walls

    Institute of Scientific and Technical Information of China (English)

    李升才; 江见鲸; 于庆荣

    2002-01-01

    Shear test results for a composite wall panel in a light composite structure system are compared with test results for shear walls in Japan in this paper. The analysis results show that this kind of composite wall panel works very well, and can be regarded as a solid panel. The composite wall panel with a hidden frame is essential for bringing its effect on shear resistance into full play. Comprehensive analysis of the shear-resistant behavior of the composite wall panel suggests that the shear of the composite shear wall panel can be controlled by the cracking strength of the web shearing diagonal crack.

  13. Theory of domain wall motion mediated magnetoelectric effects in a multiferroic composite

    Science.gov (United States)

    Petrov, V. M.; Srinivasan, G.

    2014-10-01

    A model is discussed for magnetoelectric (ME) interactions originating from the motion of magnetic domain walls (DWs) in a multiferroic composite of orthoferrites RFeO3 (RFO) with magnetic stripe domains and a piezoelectric such as lead magnesium niobate-lead titanate (PMN-PT). The DWs in RFO can be set in motion with an ac magnetic field up to a critical speed of 20 km/s, the highest for any magnetic system, leading to the excitation of bulk and shear magnetoacoustic waves. Thus, the ME coupling will arise from flexural deformation associated with DW motion (rather than the Joule magnetostriction mediated coupling under a static or quasistatic condition). A c plane orthoferrite with a single Néel-type DW in the bc plane and an ac magnetic field H along the c axis is assumed. The deflection in the bilayer due to DW motion is obtained when the DW velocity is a linear function H and the resulting induced voltage across PMN-PT is estimated. It is shown that a combination of spatial and time harmonics of the bending deformation leads to (i) a linear ME coefficient defined by αE=E/H and (ii) a quadratic ME coefficient αEQ=E/H2. The model is applied to yttrium orthoferrites (YFO) and a PMN-PT bilayer since YFO has one of the highest DW mobility amongst the orthoferrites. The coefficient αE is dependent on the DW position, and it is maximum when the DW equilibrium position is at the center of the sample. In YFO/PMN-PT the estimated low-frequency αE ˜ 30 mV/cm Oe and resonance value is 1.5 V/(cm Oe). Since orthoferrites (and PMN-PT) are transparent in the visible region and have a large Faraday rotation, the DW dynamics and the ME coupling could be studied simultaneously. The theory discussed here is of interest for studies on ME coupling and for applications such as magnetically controlled electro-optic devices.

  14. Spatio-temporal characteristics of large scale motions in a turbulent boundary layer from direct wall shear stress measurement

    Science.gov (United States)

    Pabon, Rommel; Barnard, Casey; Ukeiley, Lawrence; Sheplak, Mark

    2016-11-01

    Particle image velocimetry (PIV) and fluctuating wall shear stress experiments were performed on a flat plate turbulent boundary layer (TBL) under zero pressure gradient conditions. The fluctuating wall shear stress was measured using a microelectromechanical 1mm × 1mm floating element capacitive shear stress sensor (CSSS) developed at the University of Florida. The experiments elucidated the imprint of the organized motions in a TBL on the wall shear stress through its direct measurement. Spatial autocorrelation of the streamwise velocity from the PIV snapshots revealed large scale motions that scale on the order of boundary layer thickness. However, the captured inclination angle was lower than that determined using the classic method by means of wall shear stress and hot-wire anemometry (HWA) temporal cross-correlations and a frozen field hypothesis using a convection velocity. The current study suggests the large size of these motions begins to degrade the applicability of the frozen field hypothesis for the time resolved HWA experiments. The simultaneous PIV and CSSS measurements are also used for spatial reconstruction of the velocity field during conditionally sampled intense wall shear stress events. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1315138.

  15. Enhancement of spin Hall effect induced torques for current-driven magnetic domain wall motion: Inner interface effect

    KAUST Repository

    Bang, Do

    2016-05-23

    We investigate the current-induced domain wall motion in perpendicular magnetized Tb/Co wires with structure inversion asymmetry and different layered structures. We find that the critical current density to drive domain wall motion strongly depends on the layered structure. The lowest critical current density ∼15MA/cm2 and the highest slope of domain wall velocity curve are obtained for the wire having thin Co sublayers and more inner Tb/Co interfaces, while the largest critical current density ∼26MA/cm2 required to drive domain walls is observed in the Tb-Co alloy magnetic wire. It is found that the Co/Tb interface contributes negligibly to Dzyaloshinskii-Moriya interaction, while the effective spin-orbit torque strongly depends on the number of Tb/Co inner interfaces (n). An enhancement of the antidamping torques by extrinsic spin Hall effect due to Tb rare-earth impurity-induced skew scattering is suggested to explain the high efficiency of current-induced domain wall motion.

  16. Analysis of particle-wall interactions during particle free fall.

    Science.gov (United States)

    Chein, Reiyu; Liao, Wenyuan

    2005-08-01

    In this study, the vertical motion of a particle in a quiescent fluid falling toward a horizontal plane wall is analyzed, based on simplified models. Using the distance between the particle and wall as a parameter, the effects of various forces acting on the particle and the particle motion are examined. Without the colloidal and Brownian forces being included, the velocity of small particles is found to be approximately equal to the inverse of the drag force correction function used in this study as the particle approaches the near-wall region. Colloidal force is added to the particle equation of motion as the particle moves a distance comparable to its size. It is found that the particle might become suspended above or deposited onto the wall, depending on the Hamaker constant, the surface potentials of the particle and wall, and the thickness of the electrical double layer (EDL). For strong EDL repulsive force and weaker van der Waals (VDW) attractive force, the particle will become suspended above the wall at a distance at which the particle velocity is zero. This location is referred to as the equilibrium distance. The equilibrium distance is found to increase with increased in EDL thickness when a repulsive force barrier appears in the colloidal force interaction. For the weak EDL repulsive force and strong VDW attractive force case, the particle can become deposited onto the wall without the Brownian motion effect. The Brownian jump length was found to be very small. Many Brownian jumps would be required in a direction toward the wall for a suspended particle to become deposited.

  17. Ultrawideband through-wall radar for detecting the motion of people in real time

    Science.gov (United States)

    Nag, Soumya; Barnes, Mark A.; Payment, Tim; Holladay, Gary

    2002-07-01

    Law enforcement officers and search-and-rescue workers often face the difficult task of determining the locations of people inside a building or obscured by smoke and debris. To address this problem, Time Domain Corporation (TDC) has developed a real-time, hand-held radar to detect the motion of persons in range and azimuth through non-metallic walls. This radar is a time modulated ultra-wide band (TM-UWB) impulse radar that generates a two-dimensional (2D) representation of moving targets in real time. The intentional transmit power emitted from the radar is comparable to the FCC Part 15, Class B limits. It has the following benefits: (1) covertness because of its ultra-low power noise-like signal, (2) high resolution at low radio frequencies for penetrating building materials, (3) reduced range ambiguities and clutter fold-over because of pseudo-random time modulation, and (4) clutter rejection because of the ultra-wide bandwidth of the signal. In this paper, an outline of the key parameters of the TDC prototype radar RadarVision2000 (RV2000) and a brief description of the algorithm that generates a motion map showing the range and direction of the moving people are presented. Some typical radar images of multiple targets for a variety of building materials and cluttered environment obtained using the prototype are shown. Finally, the paper presents some preliminary results for resolving the targets in the elevation plane along with a processing technique for reducing the intensity of multi-path responses in the images.

  18. Effects of non-invasive ventilation and posture on chest wall volumes and motion in patients with amyotrophic lateral sclerosis: a case series

    Directory of Open Access Journals (Sweden)

    Cristiana M. Magalhães

    2016-01-01

    Full Text Available ABSTRACT Background The effects of non-invasive ventilation (NIV on the breathing pattern and thoracoabdominal motion of patients with amyotrophic lateral sclerosis (ALS are unknown. Objectives 1 To analyze the influence of NIV on chest wall volumes and motion assessed by optoelectronic plethysmography in ALS patients and 2 to compare these parameters in the supine and sitting positions to those of healthy individuals (without NIV. Method Nine ALS patients were evaluated in the supine position using NIV. In addition, the ALS patients and nine healthy individuals were evaluated in both sitting and supine positions. Statistical analysis was performed using the paired Student t-test or Wilcoxon test and the Student t-test for independent samples or Mann-Whitney U test. Results Chest wall volume increased significantly with NIV, mean volume=0.43 (SD=0.16L versus 0.57 (SD=0.19L (p=0.04. No significant changes were observed for the pulmonary rib cage, abdominal rib cage, or abdominal contribution. The index of the shortening velocity of the diaphragmatic muscle, mean=0.15 (SD=0.05L/s versus 0.21 (SD=0.05L/s (p<0.01, and abdominal muscles, mean=0.09 (SD=0.02L/s versus 0.14 (SD=0.06L/s (p<0.01, increased during NIV. Comparisons between the supine and sitting positions showed similar changes in chest wall motion in both groups. However, the ALS patients presented a significantly lower contribution of the abdomen in the supine position compared with the controls, mean=56 (SD=13 versus 69 (SD=10 (p=0.02. Conclusions NIV improved chest wall volumes without changing the contribution of the chest wall compartment in ALS patients. In the supine position, ALS patients had a lower contribution of the abdomen, which may indicate early diaphragmatic dysfunction.

  19. Structure, stability, and motion of dislocations in double-wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Zhang Kai-Wang; Li Zhong-Qiu; Wu Jian; Peng Xiang-Yang; Tan Xin-Jun; Sun Li-Zhong; Zhong Jian-Xin

    2012-01-01

    In this paper,a novel double-wall carbon nanotube (DWCNT) with both edge and screw dislocations is studied by using the molecular dynamics (MD) method. The differences between two adjacent tubule indexes of armchair and zigzag nanotubes are determined to be 5 and 9,respectively,by taking into account the symmetry,integrality,and thermal stability of the composite structures. It is found that melting first occurs near the dislocations,and the melting temperatures of the dislocated armchair and zigzag DWCNTs are around 2600 K-2700 K.At the premelting temperatures,the shrink of the dislocation loop,which is comprised of edge and screw dislocations,implies that the composite dislocation in DWCNTs has self-healing ability.The dislocated DWCNTs first fracture at the edge dislocations,which induces the entire break in axial tensile test. The dislocated DWCNTs have a smaller fracture strength compared to the perfect DWCNTs.Our results not only match with the dislocation glide of carbon nanotubes (CNTs) in experiments,but also can free from the electron beam radiation under experimental conditions observed by the high resolution transmission electron microscope (HRTEM),which is deemed to cause the motion of dislocation loop.

  20. Structure, stability, and motion of dislocations in double-wall carbon nanotubes

    Science.gov (United States)

    Zhang, Kai-Wang; Li, Zhong-Qiu; Wu, Jian; Peng, Xiang-Yang; Tan, Xin-Jun; Sun, Li-Zhong; Zhong, Jian-Xin

    2012-10-01

    In this paper, a novel double-wall carbon nanotube (DWCNT) with both edge and screw dislocations is studied by using the molecular dynamics (MD) method. The differences between two adjacent tubule indexes of armchair and zigzag nanotubes are determined to be 5 and 9, respectively, by taking into account the symmetry, integrality, and thermal stability of the composite structures. It is found that melting first occurs near the dislocations, and the melting temperatures of the dislocated armchair and zigzag DWCNTs are around 2600 K—2700 K. At the pre-melting temperatures, the shrink of the dislocation loop, which is comprised of edge and screw dislocations, implies that the composite dislocation in DWCNTs has self-healing ability. The dislocated DWCNTs first fracture at the edge dislocations, which induces the entire break in axial tensile test. The dislocated DWCNTs have a smaller fracture strength compared to the perfect DWCNTs. Our results not only match with the dislocation glide of carbon nanotubes (CNTs) in experiments, but also can free from the electron beam radiation under experimental conditions observed by the high resolution transmission electron microscope (HRTEM), which is deemed to cause the motion of dislocation loop.

  1. Classification of LV wall motion in cardiac MRI using kernel Dictionary Learning with a parametric approach.

    Science.gov (United States)

    Mantilla, Juan; Paredes, Jose; Bellanger, Jean-J; Donal, Erwan; Leclercq, Christophe; Medina, Ruben; Garreau, Mireille

    2015-01-01

    In this paper, we propose a parametric approach for the assessment of wall motion in Left Ventricle (LV) function in cardiac cine-Magnetic Resonance Imaging (MRI). Time-signal intensity curves (TSICs) are identified in Spatio-temporal image profiles extracted from different anatomical segments in a cardiac MRI sequence. Different parameters are constructed from specific TSICs that present a decreasing then increasing shape reflecting dynamic information of the LV contraction. The parameters extracted from these curves are related to: 1) an average curve based on a clustering process, 2) curve skewness and 3) cross correlation values between each average clustered curve and a patient-specific reference. Several tests are performed in order to construct different vectors to train a sparse classifier based on kernel Dictionary Learning (DL). Results are compared with other classifiers like Support Vector Machine (SVM) and Discriminative Dictionary Learning. The best classification performance is obtained with information of skewness and the average curve with an accuracy about 94% using the mentioned sparse based kernel DL with a radial basis function kernel.

  2. Two-character motion analysis and synthesis.

    Science.gov (United States)

    Kwon, Taesoo; Cho, Young-Sang; Park, Sang Il; Shin, Sung Yong

    2008-01-01

    In this paper, we deal with the problem of synthesizing novel motions of standing-up martial arts such as Kickboxing, Karate, and Taekwondo performed by a pair of human-like characters while reflecting their interactions. Adopting an example-based paradigm, we address three non-trivial issues embedded in this problem: motion modeling, interaction modeling, and motion synthesis. For the first issue, we present a semi-automatic motion labeling scheme based on force-based motion segmentation and learning-based action classification. We also construct a pair of motion transition graphs each of which represents an individual motion stream. For the second issue, we propose a scheme for capturing the interactions between two players. A dynamic Bayesian network is adopted to build a motion transition model on top of the coupled motion transition graph that is constructed from an example motion stream. For the last issue, we provide a scheme for synthesizing a novel sequence of coupled motions, guided by the motion transition model. Although the focus of the present work is on martial arts, we believe that the framework of the proposed approach can be conveyed to other two-player motions as well.

  3. Short-term effect of volume recruitment-derecruitment manoeuvre on chest-wall motion in Duchenne muscular dystrophy.

    Science.gov (United States)

    Meric, Henri; Falaize, Line; Pradon, Didier; Lacombe, Matthieu; Petitjean, Michel; Orlikowski, David; Prigent, Hélène; Lofaso, Frédéric

    2017-05-01

    Because progressive respiratory muscle weakness leads to decreased chest-wall motion with eventual ribcage stiffening, the purpose was to compare vital capacity (VC) and contributions of chest-wall compartments before and after volume recruitment-derecruitment manoeuvres (VRDM) in Duchenne muscular dystrophy (DMD). We studied nine patients with DMD and VC lower than 30% of predicted. VRDM was performed using 15 insufflations-exsufflations of +30 to -30 cmH2O. VC and three-dimensional chest-wall motion were measured, as well as oxygen saturation, transcutaneous partial pressure of carbon dioxide and the rapid shallow breathing index (respiratory rate/tidal volume) before (baseline) and immediately and 1 hour after VRDM. VC increased significantly immediately after VRDM (108% ± 7% of baseline, p = 0.018) but returned to baseline within 1 hour, and the rapid shallow breathing index increased significantly. The non-dominant side systematically increased immediately after VRDM ( p = 0.0077), and in the six patients with abnormal breathing asymmetry (difference >10% of VC) at baseline, this asymmetry was corrected immediately and/or 1 hour after VRDM. VRDM improved VC and reduced chest-wall motion asymmetry, but this beneficial effect waned rapidly with respiratory muscle fatigue, suggesting that VRDM may need to be repeated during the day to produce lasting benefits.

  4. A cellular scale numerical study of the effect of mechanical properties of erythrocytes on the near-wall motion of platelets

    Science.gov (United States)

    Xu, Jing; Wang, Xiao-Long; Liu, Yun-Qiao; Gong, Xiao-Bo

    2014-04-01

    The effect of mechanical properties of erythrocytes on the near-wall motion of platelets was numerically studied with the immersed boundary method. Cells were modeled as viscous-fluid-filled capsules surrounded by hyper-elastic membranes with negligible thickness. The numerical results show that with the increase of hematocrit, the near-wall approaching of platelets is enhanced, with which platelets exhibit larger deformation and orientation angle of its near-wall tank-treading motion, and the lateral force pushing platelets to the wall is increased with larger fluctuation amplitude. Meanwhile the near-wall approaching is reduced by increasing the stiffness of erythrocytes. [Figure not available: see fulltext.

  5. Motion Analysis during Sabot Opening Process

    Directory of Open Access Journals (Sweden)

    R.S. Acharya

    2007-03-01

    Full Text Available For FSAPDS projectile, the trajectory and stability are dependent on different forces indifferent phases of the motion. During the first phase gravity, aerodynamic drag along withpropellant gas force affect the motion. The motion is influenced by shock wave and mechanicalforce in sabot opening phase and the effect of time lag during opening of sabots also forms partof this work.

  6. Statistical analysis of silo wall pressures

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Berntsen, Kasper Nikolaj

    1998-01-01

    Previously published silo wall pressure measurements during plug flow of barley in alarge concrete silo are re-analysed under the hypothesis that the wall pressures are gamma-distributed.The fits of the gamma distribution type to the local pressure data from each measuring cell are satisfactory.......However, the estimated parameters of the gamma distributions turn out to be significantly inhomogeneous overthe silo wall surface. This inhomogeneity is attributed to the geometrical imperfections of the silo wall.Motivated by the engineering importance of the problem a mathematical model for constructing astochastic...

  7. Reliability Analysis of Existing Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard

    1998-01-01

    Vertical wall breakwaters are used under quite different conditions where failure of the breakwater or a part of it will have very different consequences. Further a number of existing vertical wall breakwaters have been subjected to significant wave loads which have caused partial failures...

  8. Current-induced domain wall motion in Co/Ni nano-wires with different Co and Ni thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, K; Chiba, D; Koyama, T; Yamada, G; Ono, T [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 (Japan); Tanigawa, H; Fukami, S; Suzuki, T; Ohshima, N; Ishiwata, N [NEC Corporation, 1120 Shimokuzawa, Chuo-ku, Sagamihara, Kanagawa 252-5298 (Japan); Nakatani, Y, E-mail: ono@scl.kyoto-u.ac.jp [University of Electro-communications, Chofu, Tokyo, 182-8585 (Japan)

    2011-01-01

    The authors have investigated magnetic domain wall motion induced by electric currents in ferromagnetic nano-wires made of Co/Ni multilayers. The thicknesses of Co and Ni layers were changed, whereas the numbers of layer stacks of Co and Ni were the same in all samples. The sample with thinner total Co/Ni thickness showed the lower threshold current density for the domain wall motion as an overall trend, which is qualitatively in agreement with the expectation by the theory based on the adiabatic spin-transfer model. The lowest threshold current density was 2.9x10{sup 11} A/m{sup 2} obtained in the sample with the total Co/Ni thickness of 3.4 nm and the wire width of 110 nm.

  9. On-line assessment of regional ventricular wall motion by transesophageal echocardiography with color kinesis during minimally invasive coronary artery bypass grafting.

    Science.gov (United States)

    Kotoh, K; Watanabe, G; Ueyama, K; Uozaki, M; Suzuki, M; Misaki, T; Wakasugi, M; Ito, Y

    1999-05-01

    Our objective was to determine the changes in regional ventricular wall motion during minimally invasive direct coronary artery bypass grafting by color kinesis using transesophageal echocardiography. Minimally invasive coronary artery bypass grafting was performed in 34 patients, during which transesophageal echocardiography was used. Thirteen patients had isolated disease of the left anterior descending artery. Regional ventricular wall motion was analyzed by color kinesis with the SONOS 2500 transesophageal echocardiograph (Hewlett-Packard Co, Andover, Mass). On-line assessment of regional wall motion was continued during the operation. Wall motion abnormalities during ischemia were present in 4 cases, left ventricular mid-anterior hypokinesis in 3 cases, and left ventricular apical-lateral hypokinesis in 1 case. In all cases, wall motion was maintained after bypass. In patients with total coronary occlusion, changes in wall motion did not occur during anastomosis. Color kinesis allowed us to evaluate the change in regional ventricular wall motion induced by myocardial ischemia during minimally invasive coronary artery bypass grafting both objectively and quantitatively.

  10. SVM-based classification of LV wall motion in cardiac MRI with the assessment of STE

    Science.gov (United States)

    Mantilla, Juan; Garreau, Mireille; Bellanger, Jean-Jacques; Paredes, José Luis

    2015-01-01

    In this paper, we propose an automated method to classify normal/abnormal wall motion in Left Ventricle (LV) function in cardiac cine-Magnetic Resonance Imaging (MRI), taking as reference, strain information obtained from 2D Speckle Tracking Echocardiography (STE). Without the need of pre-processing and by exploiting all the images acquired during a cardiac cycle, spatio-temporal profiles are extracted from a subset of radial lines from the ventricle centroid to points outside the epicardial border. Classical Support Vector Machines (SVM) are used to classify features extracted from gray levels of the spatio-temporal profile as well as their representations in the Wavelet domain under the assumption that the data may be sparse in that domain. Based on information obtained from radial strain curves in 2D-STE studies, we label all the spatio-temporal profiles that belong to a particular segment as normal if the peak systolic radial strain curve of this segment presents normal kinesis, or abnormal if the peak systolic radial strain curve presents hypokinesis or akinesis. For this study, short-axis cine- MR images are collected from 9 patients with cardiac dyssynchrony for which we have the radial strain tracings at the mid-papilary muscle obtained by 2D STE; and from one control group formed by 9 healthy subjects. The best classification performance is obtained with the gray level information of the spatio-temporal profiles using a RBF kernel with 91.88% of accuracy, 92.75% of sensitivity and 91.52% of specificity.

  11. Validation of a novel modified wall motion score for estimation of left ventricular ejection fraction in ischemic and non-ischemic cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Scholl, David, E-mail: David.Scholl@utoronto.ca [Imaging Research Laboratories, Robarts Research Institute, London, Ontario (Canada); Kim, Han W., E-mail: hanwkim@gmail.com [Duke Cardiovascular Magnetic Resonance Center, Division of Cardiology, Duke University, NC (United States); Shah, Dipan, E-mail: djshah@tmhs.org [The Methodist DeBakey Heart Center, Houston, TX (United States); Fine, Nowell M., E-mail: nowellfine@gmail.com [Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario (Canada); Tandon, Shruti, E-mail: standon4@uwo.ca [Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario (Canada); Thompson, Terry, E-mail: thompson@lawsonimaging.ca [Lawson Health Research Institute, London, Ontario (Canada); Department of Medical Biophysics, University of Western Ontario, London, Ontario (Canada); Drangova, Maria, E-mail: mdrangov@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London, Ontario (Canada); Department of Medical Biophysics, University of Western Ontario, London, Ontario (Canada); White, James A., E-mail: jwhite@imaging.robarts.ca [Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario (Canada); Lawson Health Research Institute, London, Ontario (Canada); Imaging Research Laboratories, Robarts Research Institute, London, Ontario (Canada)

    2012-08-15

    Background: Visual determination of left ventricular ejection fraction (LVEF) by segmental scoring may be a practical alternative to volumetric analysis of cine magnetic resonance imaging (MRI). The accuracy and reproducibility of this approach for has not been described. The purpose of this study was to validate a novel segmental visual scoring method for LVEF estimation using cine MRI. Methods: 362 patients with known or suspected cardiomyopathy were studied. A modified wall motion score (mWMS) was used to blindly score the wall motion of all cardiac segments from cine MRI imaging. The same datasets were subjected to blinded volumetric analysis using endocardial contour tracing. The population was then separated into a model cohort (N = 181) and validation cohort (N = 181), with the former used to derive a regression equation of mWMS versus true volumetric LVEF. The validation cohort was then used to test the accuracy of this regression model to estimate the true LVEF from a visually determined mWMS. Reproducibility testing of mWMS scoring was performed upon a randomly selected sample of 20 cases. Results: The regression equation relating mWMS to true LVEF in the model cohort was: LVEF = 54.23 - 0.5761 Multiplication-Sign mWMS. In the validation cohort this equation produced a strong correlation between mWMS-derived LVEF and true volumetric LVEF (r = 0.89). Bland and Altman analysis showed no systematic bias in the LVEF estimated using the mWMS (-0.3231%, 95% limits of agreement -12.22% to 11.58%). Inter-observer and intra-observer reproducibility was excellent (r = 0.93 and 0.97, respectively). Conclusion: The mWMS is a practical tool for reporting regional wall motion and provides reproducible estimates of LVEF from cine MRI.

  12. INS integrated motion analysis for autonomous vehicle navigation

    Science.gov (United States)

    Roberts, Barry; Bazakos, Mike

    1991-01-01

    The use of inertial navigation system (INS) measurements to enhance the quality and robustness of motion analysis techniques used for obstacle detection is discussed with particular reference to autonomous vehicle navigation. The approach to obstacle detection used here employs motion analysis of imagery generated by a passive sensor. Motion analysis of imagery obtained during vehicle travel is used to generate range measurements to points within the field of view of the sensor, which can then be used to provide obstacle detection. Results obtained with an INS integrated motion analysis approach are reviewed.

  13. Injection and controlled motion of conducting domain walls in improper ferroelectric Cu-Cl boracite

    Science.gov (United States)

    McQuaid, Raymond G. P.; Campbell, Michael P.; Whatmore, Roger W.; Kumar, Amit; Gregg, J. Marty

    2017-05-01

    Ferroelectric domain walls constitute a completely new class of sheet-like functional material. Moreover, since domain walls are generally writable, erasable and mobile, they could be useful in functionally agile devices: for example, creating and moving conducting walls could make or break electrical connections in new forms of reconfigurable nanocircuitry. However, significant challenges exist: site-specific injection and annihilation of planar walls, which show robust conductivity, has not been easy to achieve. Here, we report the observation, mechanical writing and controlled movement of charged conducting domain walls in the improper-ferroelectric Cu3B7O13Cl. Walls are straight, tens of microns long and exist as a consequence of elastic compatibility conditions between specific domain pairs. We show that site-specific injection of conducting walls of up to hundreds of microns in length can be achieved through locally applied point-stress and, once created, that they can be moved and repositioned using applied electric fields.

  14. Automated grading of left ventricular segmental wall motion by an artificial neural network using color kinesis images

    Directory of Open Access Journals (Sweden)

    L.O. Murta Jr.

    2006-01-01

    Full Text Available The present study describes an auxiliary tool in the diagnosis of left ventricular (LV segmental wall motion (WM abnormalities based on color-coded echocardiographic WM images. An artificial neural network (ANN was developed and validated for grading LV segmental WM using data from color kinesis (CK images, a technique developed to display the timing and magnitude of global and regional WM in real time. We evaluated 21 normal subjects and 20 patients with LVWM abnormalities revealed by two-dimensional echocardiography. CK images were obtained in two sets of viewing planes. A method was developed to analyze CK images, providing quantitation of fractional area change in each of the 16 LV segments. Two experienced observers analyzed LVWM from two-dimensional images and scored them as: 1 normal, 2 mild hypokinesia, 3 moderate hypokinesia, 4 severe hypokinesia, 5 akinesia, and 6 dyskinesia. Based on expert analysis of 10 normal subjects and 10 patients, we trained a multilayer perceptron ANN using a back-propagation algorithm to provide automated grading of LVWM, and this ANN was then tested in the remaining subjects. Excellent concordance between expert and ANN analysis was shown by ROC curve analysis, with measured area under the curve of 0.975. An excellent correlation was also obtained for global LV segmental WM index by expert and ANN analysis (R² = 0.99. In conclusion, ANN showed high accuracy for automated semi-quantitative grading of WM based on CK images. This technique can be an important aid, improving diagnostic accuracy and reducing inter-observer variability in scoring segmental LVWM.

  15. Automated grading of left ventricular segmental wall motion by an artificial neural network using color kinesis images.

    Science.gov (United States)

    Murta, L O; Ruiz, E E S; Pazin-Filho, A; Schmidt, A; Almeida-Filho, O C; Simões, M V; Marin-Neto, J A; Maciel, B C

    2006-01-01

    The present study describes an auxiliary tool in the diagnosis of left ventricular (LV) segmental wall motion (WM) abnormalities based on color-coded echocardiographic WM images. An artificial neural network (ANN) was developed and validated for grading LV segmental WM using data from color kinesis (CK) images, a technique developed to display the timing and magnitude of global and regional WM in real time. We evaluated 21 normal subjects and 20 patients with LVWM abnormalities revealed by two-dimensional echocardiography. CK images were obtained in two sets of viewing planes. A method was developed to analyze CK images, providing quantitation of fractional area change in each of the 16 LV segments. Two experienced observers analyzed LVWM from two-dimensional images and scored them as: 1) normal, 2) mild hypokinesia, 3) moderate hypokinesia, 4) severe hypokinesia, 5) akinesia, and 6) dyskinesia. Based on expert analysis of 10 normal subjects and 10 patients, we trained a multilayer perceptron ANN using a back-propagation algorithm to provide automated grading of LVWM, and this ANN was then tested in the remaining subjects. Excellent concordance between expert and ANN analysis was shown by ROC curve analysis, with measured area under the curve of 0.975. An excellent correlation was also obtained for global LV segmental WM index by expert and ANN analysis (R2 = 0.99). In conclusion, ANN showed high accuracy for automated semi-quantitative grading of WM based on CK images. This technique can be an important aid, improving diagnostic accuracy and reducing inter-observer variability in scoring segmental LVWM.

  16. Temperature estimation in a ferromagnetic Fe-Ni nanowire involving a current-driven domain wall motion.

    Science.gov (United States)

    Yamaguchi, A; Hirohata, A; Ono, T; Miyajima, H

    2012-01-18

    We observed a magnetic domain wall (DW) motion induced by the spin-polarized pulsed current in a nanoscale Fe(19)Ni(81) wire using a magnetic force microscope. High current density, which is of the order of 10(11) A m(-2), was required for the DW motion. A simple method to estimate the temperature of the wire was developed by comparing the wire resistance measured during the DW motion with the temperature dependence of the wire resistance. Using this method, we found the temperature of the wire was proportional to the square of the current density and became just beneath at the threshold Curie temperature. Our experimental data qualitatively support this analytical model that the temperature is proportional to the resistivity, thickness, width of the wire and the square of the current density, and also inversely proportional to the thermal conductivity.

  17. Computer vision analysis of image motion by variational methods

    CERN Document Server

    Mitiche, Amar

    2014-01-01

    This book presents a unified view of image motion analysis under the variational framework. Variational methods, rooted in physics and mechanics, but appearing in many other domains, such as statistics, control, and computer vision, address a problem from an optimization standpoint, i.e., they formulate it as the optimization of an objective function or functional. The methods of image motion analysis described in this book use the calculus of variations to minimize (or maximize) an objective functional which transcribes all of the constraints that characterize the desired motion variables. The book addresses the four core subjects of motion analysis: Motion estimation, detection, tracking, and three-dimensional interpretation. Each topic is covered in a dedicated chapter. The presentation is prefaced by an introductory chapter which discusses the purpose of motion analysis. Further, a chapter is included which gives the basic tools and formulae related to curvature, Euler Lagrange equations, unconstrained de...

  18. Longitudinal peak strain detects a smaller risk area than visual assessment of wall motion in acute myocardial infarction

    Directory of Open Access Journals (Sweden)

    Brudin Lars

    2010-01-01

    Full Text Available Abstract Background Opening of an occluded infarct related artery reduces infarct size and improves survival in acute ST-elevation myocardial infarction (STEMI. In this study we performed tissue Doppler analysis (peak strain, displacement, mitral annular movement (MAM and compared with visual assessment for the study of the correlation of measurements of global, regional and segmental function with final infarct size and transmurality. In addition, myocardial risk area was determined and a prediction sought for the development of infarct transmurality ≥50%. Methods Twenty six patients with STEMI submitted for primary percutaneous coronary intervention (PCI were examined with echocardiography on the catheterization table. Four to eight weeks later repeat echocardiography was performed for reassessment of function and magnetic resonance imaging for the determination of final infarct size and transmurality. Results On a global level, wall motion score index (WMSI, ejection fraction (EF, strain, and displacement all showed significant differences (p ≤ 0.001, p ≤ 0.001, p ≤ 0.001 and p = 0.03 between the two study visits, but MAM did not (p = 0.17. On all levels (global, regional and segmental and both pre- and post PCI, WMSI showed a higher correlation with scar transmurality compared to strain. We found that both strain and WMSI predicted the development of scar transmurality ≥50%, but strain added no significant information to that obtained with WMSI in a logistic regression analysis. Conclusions In patients with acute STEMI, WMSI, EF, strain, and displacement showed significant changes between the pre- and post PCI exam. In a ROC-analysis, strain had 64% sensitivity at 80% specificity and WMSI around 90% sensitivity at 80% specificity for the detection of scar with transmurality ≥50% at follow-up.

  19. ELASTO-PLASTIC BACK ANALYSIS OF FROZEN SOIL WALL

    Institute of Scientific and Technical Information of China (English)

    张铭; 翁家杰

    1994-01-01

    The paper briefly describes the range and methods of the research on the stability of frozen wall. Using the Back Analysis Method combining with the model test of frozen wall, the comprchcnsire study on the stability of frozen wall is firstly carried out by the authors. Finally, a new viewpointof adopting limited strain as the major criteria of stability in frozen soil cngincertng is proposed.

  20. Analysis of motion in speed skating

    Science.gov (United States)

    Koga, Yuzo; Nishimura, Tetsu; Watanabe, Naoki; Okamoto, Kousuke; Wada, Yuhei

    1997-03-01

    A motion on sports has been studied by many researchers from the view of the medical, psychological and mechanical fields. Here, we try to analyze a speed skating motion dynamically for an aim of performing the best record. As an official competition of speed skating is performed on the round rink, the skating motion must be studied on the three phases, that is, starting phase, straight and curved course skating phase. It is indispensable to have a visual data of a skating motion in order to analyze kinematically. So we took a several subject's skating motion by 8 mm video cameras in order to obtain three dimensional data. As the first step, the movement of the center of gravity of skater (abbreviate to C. G.) is discussed in this paper, because a skating motion is very complicated. The movement of C. G. will give an information of the reaction force to a skate blade from the surface of ice. We discuss the discrepancy of several skating motion by studied subjects. Our final goal is to suggest the best skating form for getting the finest record.

  1. Clinical Study of the Ascending Aorta Wall Motion by Velocity Vector Imaging in Patients with Primary Hypertension

    Institute of Scientific and Technical Information of China (English)

    Lei WANG; Jing WANG; Mingxing XIE; Xinfang WANG; Qing LV; Ming CHEN; Shaoping ZHENG

    2009-01-01

    We studied the wall motion characteristics of the ascending aorta by velocity vector im-aging (VVI) in primary hypertension patients.The ascending aortas both in 30 patients with primary hypertension and 30 normal controls were examined by Acuson sequoia 512 equiped with VVI.The maximum velocity (Vs,Ve) of every point on the anterior wall of ascending aorta both in systole and diastole was measured.The aortic diameter was wider in the hypertension patients than that in the healthy subjects (P0.05).The velocity curves of the anterior wall of ascending aorta both in the hypertension and healthy subjects were regular,and the curve in systole was named S wave and that in diastole named E wave.The velocity of S wave and E wave was slower in the hypertension pa-tients than that in the healthy subjects (P<0.05).The time to peak of S wave on the anterior wall of ascending aorta in systole was shorter in the hypertension patients than in the healthy subjects (P<0.05).VVI could be used to accurately and directly observe the movement character of the as-cending aorta walls,which would help us understand the elasticity of great arteries in patients with hypertension.

  2. Numerical Analysis of Helicopter Rotor Hovering in Close Proximity to the Ground with a Wall

    Science.gov (United States)

    Itoga, Noriaki; Iboshi, Naohiro; Horimoto, Mitsumasa; Saito, Shigeru; Tanabe, Yasutada

    In rescue operations and emergency medical services, helicopters are frequently required to operate near the ground with obstacles such as buildings and sidewalls of highway. In this paper, numerical analysis of helicopter rotor hovering in close proximity to the ground with an obstacle is done by solving unsteady 3D compressible Euler equations with an overlapped grid system. The obstacle is simulated by a wall vertically set up on the ground. The parameters for numerical analysis are the rotor height and distance from the rotor-hub-center to the wall. The effects of combinations of these parameters on the flowfields around the rotor, inflow distributions on the rotor disc and behaviors of blade flapping motion are discussed. It is also clarified the cause that the helicopter rotor hovering in close proximity to the ground with a wall does not have the enough ground effect depending on the combinations of these parameters.

  3. Motion

    CERN Document Server

    Graybill, George

    2007-01-01

    Take the mystery out of motion. Our resource gives you everything you need to teach young scientists about motion. Students will learn about linear, accelerating, rotating and oscillating motion, and how these relate to everyday life - and even the solar system. Measuring and graphing motion is easy, and the concepts of speed, velocity and acceleration are clearly explained. Reading passages, comprehension questions, color mini posters and lots of hands-on activities all help teach and reinforce key concepts. Vocabulary and language are simplified in our resource to make them accessible to str

  4. Carotid artery longitudinal wall motion is associated with local blood velocity and left ventricular rotational, but not longitudinal, mechanics.

    Science.gov (United States)

    Au, Jason S; Ditor, David S; MacDonald, Maureen J; Stöhr, Eric J

    2016-07-01

    Recent studies have identified a predictable movement pattern of the common carotid artery wall in the longitudinal direction. While there is evidence that the magnitude of this carotid artery longitudinal wall motion (CALM) is sensitive to cardiovascular health status, little is known about the determinants of CALM The purpose of this integrative study was to evaluate the contribution of left ventricular (LV) cardiac motion and local blood velocity to CALM Simultaneous ultrasound measurements of CALM, common carotid artery mean blood velocity (MBV), and left ventricular motion were performed in ten young, healthy individuals (6 males; 22 ± 1 years). Peak anterograde CALM occurred at a similar time as peak MBV (18.57 ± 3.98% vs. 18.53 ± 2.81% cardiac cycle; t-test: P = 0.94; ICC: 0.79, P longitudinal displacement was not associated with peak CALM (r = 0.11, P = 0.77). These results suggest that the rotational mechanical movement of the LV base may be closely associated with longitudinal mechanics in the carotid artery. This finding may have important implications for interpreting the complex relationship between ventricular and vascular function.

  5. Time motion analysis of international kickboxing competition.

    Science.gov (United States)

    Ouergui, Ibrahim; Hssin, Nizar; Haddad, Monoem; Franchini, Emerson; Behm, David; Wong, Del P; Gmada, Nabil; Bouhlel, Ezzedine

    2014-06-17

    The objective of the study was to analyze the time structure of high-level kickboxing matches. A total of 45 combats from two male World Championships were monitored using a time motion analysis system. The combat time structure (i.e., high-intensity activity: HIA; low-intensity activity: LIA; and referee breaks or pauses) during competition and weight divisions was determined and compared. Results indicated that the time structures were HIA: 2.2± 1.2 s; LIA: 2.3± 0.8 s; pauses: 5.4± 4.3 s; and 3.4±1.2 s between two subsequent HIA. The fighting to non-fighting ratio was found to be 1:1. Moreover, the number of HIA and LIA and the time of LIA decreased in latter rounds (e.g., the average number of HIA were 27.1±7.1, 25.1±6.6 and 24.9±6.1 respectively for round1, 2 and 3), meanwhile the time and number of pauses increased (e.g., the average pause times were 12.8±11.4, 22.3±22.6 and 24.6±23.3s respectively for round1, 2 and 3). The activity times did not differ among weight categories. The present results confirm the intermittent nature of kickboxing competition and provide coaches with more information on how to structure training sessions to mimic the physical demands in competition.

  6. Ground motion estimation and nonlinear seismic analysis

    Energy Technology Data Exchange (ETDEWEB)

    McCallen, D.B.; Hutchings, L.J.

    1995-08-14

    Site specific predictions of the dynamic response of structures to extreme earthquake ground motions are a critical component of seismic design for important structures. With the rapid development of computationally based methodologies and powerful computers over the past few years, engineers and scientists now have the capability to perform numerical simulations of many of the physical processes associated with the generation of earthquake ground motions and dynamic structural response. This paper describes application of a physics based, deterministic, computational approach for estimation of earthquake ground motions which relies on site measurements of frequently occurring small (i.e. M < 3 ) earthquakes. Case studies are presented which illustrate application of this methodology for two different sites, and nonlinear analyses of a typical six story steel frame office building are performed to illustrate the potential sensitivity of nonlinear response to site conditions and proximity to the causative fault.

  7. Interpretation of cardiac wall motion from cine-MRI combined with parametric imaging based on the Hilbert transform.

    Science.gov (United States)

    Benameur, Narjes; Caiani, Enrico Gianluca; Arous, Younes; Abdallah, Nejmeddine Ben; Kraiem, Tarek

    2017-08-01

    The aim of this study was to test and validate the clinical impact of parametric amplitude images obtained using the Hilbert transform on the regional interpretation of cardiac wall motion abnormalities from cine-MR images by non-expert radiologists compared with expert consensus. Cine-MRI short-axis images obtained in 20 patients (10 with myocardial infarction, 5 with myocarditis and 5 with normal function) were processed to compute a parametric amplitude image for each using the Hilbert transform. Two expert radiologists blindly reviewed the cine-MR images to define a gold standard for wall motion interpretation for each left ventricular sector. Two non-expert radiologists reviewed and graded the same images without and in combination with parametric images. Grades assigned to each segment in the two separate sessions were compared with the gold standard. According to expert interpretation, 264/320 (82.5%) segments were classified as normal and 56/320 (17.5%) were considered abnormal. The accuracy of the non-expert radiologists' grades compared to the gold standard was significantly improved by adding parametric images (from 87.2 to 94.6%) together with sensitivity (from 64.29 to 84.4%) and specificity (from 92 to 96.9%), also resulting in reduced interobserver variability (from 12.8 to 5.6%). The use of parametric amplitude images based on the Hilbert transform in conjunction with cine-MRI was shown to be a promising technique for improvement of the detection of left ventricular wall motion abnormalities in less expert radiologists.

  8. Analysis of accelerated motion in the theory of relativity

    Science.gov (United States)

    Jones, R. T.

    1976-01-01

    Conventional treatments of accelerated motion in the theory of relativity have led to certain difficulties of interpretation. Certain reversals in the apparent gravitational field of an accelerated body may be avoided by simpler analysis based on the use of restricted conformal transformations. In the conformal theory the velocity of light remains constant even for experimenters in accelerated motion. The problem considered is that of rectilinear motion with a variable velocity. The motion takes place along the x or x' axis of two coordinate systems.

  9. Clinical impact of ' in-treatment' wall motion abnormalities in hypertensive patients with left ventricular hypertrophy: the LIFE study

    DEFF Research Database (Denmark)

    Cicala, S.; Simone, G. de; Wachtell, K.;

    2008-01-01

    to analyze the primary composite endpoint of cardiovascular death, MI, or stroke and, separately, for fatal and nonfatal MI and hospitalized heart failure. Results During a mean follow-up of 4.8 years, an event was recorded in 67 ( 9%) patients. In Cox models after adjusting for age, gender, treatment, blood......, however, never been investigated. We examined whether 'in- treatment' wall motion abnormalities predicted outcome in the Losartan Intervention For Endpoint ( LIFE) reduction in hypertension echocardiographic substudy. Methods We studied 749 patients without coronary artery disease, myocardial infarction...

  10. Construction of a two-parameter empirical model of left ventricle wall motion using cardiac tagged magnetic resonance imaging data

    Directory of Open Access Journals (Sweden)

    Shi Jack J

    2012-10-01

    Full Text Available Abstract Background A one-parameter model was previously proposed to characterize the short axis motion of the LV wall at the mid-ventricle level. The single parameter of this model was associated with the radial contraction of myocardium, but more comprehensive model was needed to account for the rotation at the apex and base levels. The current study developed such model and demonstrated its merits and limitations with examples. Materials and methods The hearts of five healthy individuals were visualized using cardiac tagged magnetic resonance imaging (tMRI covering the contraction and relaxation phases. Based on the characteristics of the overall dynamics of the LV wall, its motion was represented by a combination of two components - radial and rotational. Each component was represented by a transformation matrix with a time-dependent variable α or β. Image preprocessing step and model fitting algorithm were described and applied to estimate the temporal profiles of α and β within a cardiac cycle at the apex, mid-ventricle and base levels. During this process, the tagged lines of the acquired images served as landmark reference for comparing against the model prediction of the motion. Qualitative and quantitative analyses were performed for testing the performance of the model and thus its validation. Results The α and β estimates exhibited similarities in values and temporal trends once they were scaled by the radius of the epicardium (repiand plotted against the time scaled by the period of the cardiac cycle (Tcardiac of each heart measured during the data acquisition. α/repi peaked at about Δt/Tcardiac=0.4 and with values 0.34, 0.4 and 0.3 for the apex, mid-ventricle and base level, respectively. β/repi similarly maximized in amplitude at about Δt/Tcardiac=0.4, but read 0.2 for the apex and - 0.08 for the base level. The difference indicated that the apex twisted more than the base. Conclusion It is feasible to empirically model

  11. The reliability of echocardiographic left ventricular wall motion index to identify high-risk patients for multicenter studies

    DEFF Research Database (Denmark)

    Gislason, Gunnar H; Gadsbøll, Niels; Quinones, Miguel A

    2006-01-01

    overall agreement for identifying patients with severe impairment of LV function. This not only underscores the value of LV-WMI as a useful tool for selecting high-risk patients to be included in multicenter studies but also serves to warn against the use of rigid cutoff values for WMI in the treatment......OBJECTIVE: To study whether the use of echocardiographic left ventricular (LV) wall motion index (WMI) is a dependable parameter for identifying patients with LV dysfunction to be enrolled in multicenter trials. METHODS: Videotaped echocardiographic examinations from 200 randomly selected patients...

  12. Collective coordinate models of domain wall motion in perpendicularly magnetized systems under the spin hall effect and longitudinal fields

    Science.gov (United States)

    Nasseri, S. Ali; Moretti, Simone; Martinez, Eduardo; Serpico, Claudio; Durin, Gianfranco

    2017-03-01

    Recent studies on heterostructures of ultrathin ferromagnets sandwiched between a heavy metal layer and an oxide have highlighted the importance of spin-orbit coupling (SOC) and broken inversion symmetry in domain wall (DW) motion. Specifically, chiral DWs are stabilized in these systems due to the Dzyaloshinskii-Moriya interaction (DMI). SOC can also lead to enhanced current induced DW motion, with the Spin Hall effect (SHE) suggested as the dominant mechanism for this observation. The efficiency of SHE driven DW motion depends on the internal magnetic structure of the DW, which could be controlled using externally applied longitudinal in-plane fields. In this work, micromagnetic simulations and collective coordinate models are used to study current-driven DW motion under longitudinal in-plane fields in perpendicularly magnetized samples with strong DMI. Several extended collective coordinate models are developed to reproduce the micromagnetic results. While these extended models show improvements over traditional models of this kind, there are still discrepancies between them and micromagnetic simulations which require further work.

  13. Reliability Analysis and Optimal Design of Monolithic Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, Hans F.; Christiani, E.

    1994-01-01

    Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of the most important failure modes, sliding failure, failure of the foundation and overturning failure are described . Relevant design variables are identified and relia......Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of the most important failure modes, sliding failure, failure of the foundation and overturning failure are described . Relevant design variables are identified...

  14. Motion Picture and Videotape Analysis of Behavior.

    Science.gov (United States)

    Carpenter, Geoffrey C.; Duvall, David

    1983-01-01

    Use of motion pictures and videotape recordings to analyze animal behavior is described. Indicates that accuracy/amount of data available is greatly increased and that simultaneous behaviors of different animals can be studied or individual behavior patterns increased/decreased, providing observers with temporal perceptions similar to the animals…

  15. Inertial navigation sensor integrated motion analysis for autonomous vehicle navigation

    Science.gov (United States)

    Roberts, Barry; Bhanu, Bir

    1992-01-01

    Recent work on INS integrated motion analysis is described. Results were obtained with a maximally passive system of obstacle detection (OD) for ground-based vehicles and rotorcraft. The OD approach involves motion analysis of imagery acquired by a passive sensor in the course of vehicle travel to generate range measurements to world points within the sensor FOV. INS data and scene analysis results are used to enhance interest point selection, the matching of the interest points, and the subsequent motion-based computations, tracking, and OD. The most important lesson learned from the research described here is that the incorporation of inertial data into the motion analysis program greatly improves the analysis and makes the process more robust.

  16. Quantification of the relative contribution of the different right ventricular wall motion components to right ventricular ejection fraction: the ReVISION method.

    Science.gov (United States)

    Lakatos, Bálint; Tősér, Zoltán; Tokodi, Márton; Doronina, Alexandra; Kosztin, Annamária; Muraru, Denisa; Badano, Luigi P; Kovács, Attila; Merkely, Béla

    2017-03-27

    Three major mechanisms contribute to right ventricular (RV) pump function: (i) shortening of the longitudinal axis with traction of the tricuspid annulus towards the apex; (ii) inward movement of the RV free wall; (iii) bulging of the interventricular septum into the RV and stretching the free wall over the septum. The relative contribution of the aforementioned mechanisms to RV pump function may change in different pathological conditions.Our aim was to develop a custom method to separately assess the extent of longitudinal, radial and anteroposterior displacement of the RV walls and to quantify their relative contribution to global RV ejection fraction using 3D data sets obtained by echocardiography.Accordingly, we decomposed the movement of the exported RV beutel wall in a vertex based manner. The volumes of the beutels accounting for the RV wall motion in only one direction (either longitudinal, radial, or anteroposterior) were calculated at each time frame using the signed tetrahedron method. Then, the relative contribution of the RV wall motion along the three different directions to global RV ejection fraction was calculated either as the ratio of the given direction's ejection fraction to global ejection fraction and as the frame-by-frame RV volume change (∆V/∆t) along the three motion directions.The ReVISION (Right VentrIcular Separate wall motIon quantificatiON) method may contribute to a better understanding of the pathophysiology of RV mechanical adaptations to different loading conditions and diseases.

  17. Cardiac nonrigid motion analysis from image sequences

    Institute of Scientific and Technical Information of China (English)

    LIU Huafeng

    2006-01-01

    Noninvasive estimation of the soft tissue kinematics properties from medical image sequences has many important clinical and physiological implications, such as the diagnosis of heart diseases and the understanding of cardiac mechanics. In this paper, we present a biomechanics based strategy, framed as a priori constraints for the ill-posed motion recovery problema, to realize estimation of the cardiac motion and deformation parameters. By constructing the heart dynamics system equations from biomechanics principles, we use the finite element method to generate smooth estimates.of heart kinematics throughout the cardiac cycle. We present the application of the strategy to the estimation of displacements and strains from in vivo left ventricular magnetic resonance image sequence.

  18. Dynamic metabolic flux analysis of plant cell wall synthesis.

    Science.gov (United States)

    Chen, Xuewen; Alonso, Ana P; Shachar-Hill, Yair

    2013-07-01

    The regulation of plant cell wall synthesis pathways remains poorly understood. This has become a bottleneck in designing bioenergy crops. The goal of this study was to analyze the regulation of plant cell wall precursor metabolism using metabolic flux analysis based on dynamic labeling experiments. Arabidopsis T87 cells were cultured heterotrophically with (13)C labeled sucrose. The time course of ¹³C labeling patterns in cell wall precursors and related sugar phosphates was monitored using liquid chromatography tandem mass spectrometry until steady state labeling was reached. A kinetic model based on mass action reaction mechanisms was developed to simulate the carbon flow in the cell wall synthesis network. The kinetic parameters of the model were determined by fitting the model to the labeling time course data, cell wall composition, and synthesis rates. A metabolic control analysis was performed to predict metabolic regulations that may improve plant biomass composition for biofuel production. Our results describe the routes and rates of carbon flow from sucrose to cell wall precursors. We found that sucrose invertase is responsible for the entry of sucrose into metabolism and UDP-glucose-4-epimerase plays a dominant role in UDP-Gal synthesis in heterotrophic Aradidopsis cells under aerobic conditions. We also predicted reactions that exert strong regulatory influence over carbon flow to cell wall synthesis and its composition.

  19. Modeling for Deformable Body and Motion Analysis: A Review

    Directory of Open Access Journals (Sweden)

    Hailang Pan

    2013-01-01

    Full Text Available This paper surveys the modeling methods for deformable human body and motion analysis in the recent 30 years. First, elementary knowledge of human expression and modeling is introduced. Then, typical human modeling technologies, including 2D model, 3D surface model, and geometry-based, physics-based, and anatomy-based approaches, and model-based motion analysis are summarized. Characteristics of these technologies are analyzed. The technology accumulation in the field is outlined for an overview.

  20. Maritime Group Motion Analysis: Representation, Learning, Recognition, and Deviation Detection

    Science.gov (United States)

    2017-02-01

    Maritime Group Motion Analysis : Representation, Learning, Recognition, and Deviation Detection § Allen Waxman MultiSensor Scientific, LLC...while the authors were employed by, or sub-contractors of, Intelligent Software Solutions, Inc., of Colorado Springs, CO, USA, funded under contract...reading the PDF file of this manuscript.) Abstract - This paper introduces new concepts and methods in the analysis of group motions over extended

  1. Magnet Fall inside a Conductive Pipe: Motion and the Role of the Pipe Wall Thickness

    Science.gov (United States)

    Donoso, G.; Ladera, C. L.; Martin, P.

    2009-01-01

    Theoretical models and experimental results are presented for the retarded fall of a strong magnet inside a vertical conductive non-magnetic tube. Predictions and experimental results are in good agreement modelling the magnet as a simple magnetic dipole. The effect of varying the pipe wall thickness on the retarding magnetic drag is studied for…

  2. Speed limit in internal space of domain walls via all-order effective action of moduli motion

    Science.gov (United States)

    Eto, Minoru; Hashimoto, Koji

    2016-03-01

    We find that motion in internal moduli spaces of generic domain walls has an upper bound for its velocity. Our finding is based on our generic formula for all-order effective actions of internal moduli parameter of domain wall solitons. It is known that the Nambu-Goldstone mode Z associated with spontaneous breaking of translation symmetry obeys a Nambu-Goto effective Lagrangian √{1 -(∂0Z )2 } detecting the speed of light (|∂0Z |=1 ) in the target spacetime. Solitons can have internal moduli parameters as well, associated with a breaking of internal symmetries such as a phase rotation acting on a field. We obtain, for generic domain walls, an effective Lagrangian of the internal moduli ɛ to all orders in (∂ɛ ). The Lagrangian is given by a function of the Nambu-Goto Lagrangian: L =g (√{1 +(∂μɛ )2 }). This shows generically the existence of an upper bound on ∂0ɛ , i.e., a speed limit in the internal space. The speed limit exists even for solitons in some nonrelativistic field theories, where we find that ɛ is a type I Nambu-Goldstone mode that also obeys a nonlinear dispersion to reach the speed limit. This offers a possibility of detecting the speed limit in condensed matter experiments.

  3. Speed limit in internal space of domain walls via all-order effective action of moduli motion

    CERN Document Server

    Eto, Minoru

    2015-01-01

    We find that motion in internal moduli spaces of generic domain walls has an upper bound for its velocity. Our finding is based on our generic formula for all-order effective actions of internal moduli parameter of domain wall solitons. It is known that the Nambu-Goldstone mode $Z$ associated with spontaneous breaking of translation symmetry obeys a Nambu-Goto effective Lagrangian $\\sqrt{1 - (\\partial_0 Z)^2}$ detecting the speed of light ($|\\partial_0 Z|=1$) in the target spacetime. Solitons can have internal moduli parameters as well, associated with a breaking of internal symmetries such as a phase rotation acting on a field. We obtain, for generic domain walls, an effective Lagrangian of the internal moduli $\\epsilon$ to all order in $(\\partial \\epsilon)$. The Lagrangian is given by a function of the Nambu-Goto Lagrangian: $L = g(\\sqrt{1 + (\\partial_\\mu \\epsilon)^2})$. This shows generically the existence of an upper bound on $\\partial_0 \\epsilon$, i.e. a speed limit in the internal space. The speed limit...

  4. Complex polarization analysis of particle motion

    OpenAIRE

    Vidale, John E.

    1986-01-01

    Knowledge of particle motion polarization aids in identifying phases on three-component seismograms. The scheme of Montalbetti and Kanasewich (1970) is extended to analytic three-component seismograms, where the imaginary part of the signal is the Hilbert transform of the real part. This scheme has only one free parameter, the length of the time window over which the polarization parameters are estimated, so it can be applied in a routine way to three-component data. The azimuth and dip of th...

  5. Hierarchical Aligned Cluster Analysis for Temporal Clustering of Human Motion.

    Science.gov (United States)

    Zhou, Feng; De la Torre, Fernando; Hodgins, Jessica K

    2013-03-01

    Temporal segmentation of human motion into plausible motion primitives is central to understanding and building computational models of human motion. Several issues contribute to the challenge of discovering motion primitives: the exponential nature of all possible movement combinations, the variability in the temporal scale of human actions, and the complexity of representing articulated motion. We pose the problem of learning motion primitives as one of temporal clustering, and derive an unsupervised hierarchical bottom-up framework called hierarchical aligned cluster analysis (HACA). HACA finds a partition of a given multidimensional time series into m disjoint segments such that each segment belongs to one of k clusters. HACA combines kernel k-means with the generalized dynamic time alignment kernel to cluster time series data. Moreover, it provides a natural framework to find a low-dimensional embedding for time series. HACA is efficiently optimized with a coordinate descent strategy and dynamic programming. Experimental results on motion capture and video data demonstrate the effectiveness of HACA for segmenting complex motions and as a visualization tool. We also compare the performance of HACA to state-of-the-art algorithms for temporal clustering on data of a honey bee dance. The HACA code is available online.

  6. Multi-scale AM-FM motion analysis of ultrasound videos of carotid artery plaques

    Science.gov (United States)

    Murillo, Sergio; Murray, Victor; Loizou, C. P.; Pattichis, C. S.; Pattichis, Marios; Barriga, E. Simon

    2012-03-01

    An estimated 82 million American adults have one or more type of cardiovascular diseases (CVD). CVD is the leading cause of death (1 of every 3 deaths) in the United States. When considered separately from other CVDs, stroke ranks third among all causes of death behind diseases of the heart and cancer. Stroke accounts for 1 out of every 18 deaths and is the leading cause of serious long-term disability in the United States. Motion estimation of ultrasound videos (US) of carotid artery (CA) plaques provides important information regarding plaque deformation that should be considered for distinguishing between symptomatic and asymptomatic plaques. In this paper, we present the development of verifiable methods for the estimation of plaque motion. Our methodology is tested on a set of 34 (5 symptomatic and 29 asymptomatic) ultrasound videos of carotid artery plaques. Plaque and wall motion analysis provides information about plaque instability and is used in an attempt to differentiate between symptomatic and asymptomatic cases. The final goal for motion estimation and analysis is to identify pathological conditions that can be detected from motion changes due to changes in tissue stiffness.

  7. Analysis of Dynamic Coupling Characteristics of the Slope Reinforced by Sheet Pile Wall

    Directory of Open Access Journals (Sweden)

    H. L. Qu

    2017-01-01

    Full Text Available Large deformation of slope caused by earthquake can lead to the loss of stability of slope and its retaining structures. At present, there have been some research achievements about the slope reinforcement of stabilizing piles. However, due to the complexity of the structural system, the coupling relationship between soil and pile is still not well understood. Hence it is of great necessity to study its dynamic characteristics further. In view of this, a numerical model was established by FLAC3D in this paper, and the deformation and stress nephogram of sheet pile wall in peak ground motion acceleration (PGA at 0.1 g, 0.2 g, and 0.4 g were obtained. Through the analysis, some conclusions were obtained. Firstly, based on the nephogram of motion characteristics and the positions of the slip surface and the retaining wall, the reinforced slope can be divided into 6 sections approximatively, namely, the sliding body parts of A, B, C, D, and E and the bedrock part F. Secondly, the deformation and stress distributions of slope reinforced by sheet pile wall were carefully studied. Based on the results of deformation calculation from time history analysis, the interaction force between structure and soil can be estimated by the difference of peak horizontal displacements, and the structure-soil coupling law under earthquake can be studied by this approach.

  8. Linear modeling of turbulent skin-friction reduction due to spanwise wall motion

    Science.gov (United States)

    Duque-Daza, Carlos; Baig, Mirza; Lockerby, Duncan; Chernyshenko, Sergei; Davies, Christopher; University of Warwick Team; Imperial College Team; Cardiff University Team

    2012-11-01

    We present a study on the effect of streamwise-travelling waves of spanwise wall velocity on the growth of near-wall turbulent streaks using a linearized formulation of the Navier-Stokes equations. The changes in streak amplification due to the travelling waves induced by the wall velocity are compared to published results of direct numerical simulation (DNS) predictions of the turbulent skin-friction reduction over a range of parameters; a clear correlation between these two sets of results is observed. Additional linearized simulations but at a much higher Reynolds numbers, more relevant to aerospace applications, produce results that show no marked differences to those obtained at low Reynolds number. It is also observed that a close correlation exists between DNS data of drag reduction and a very simple characteristic of the ``generalized'' Stokes layer generated by the streamwise-travelling waves. Carlos.Duque-Daza@warwick.ac.uk - School of Engineering, University of Warwick, Coventry CV4 7AL, UK caduqued@unal.edu.co - Department of Mechanical and Mechatronics Engineering, Universidad Nacional de Colombia.

  9. Nanoparticle stochastic motion in the inertial regime and hydrodynamic interactions close to a cylindrical wall

    OpenAIRE

    Vitoshkin, Helena; Yu, Hsiu-Yu; Eckmann, David M.; Ayyaswamy, Portonovo S.; Radhakrishnan, Ravi

    2016-01-01

    We have carried out direct numerical simulations (DNS) of the fluctuating Navier-Stokes equation together with the particle equations governing the motion of a nanosized particle or nanoparticle (NP) in a cylindrical tube. The effects of the confining boundary, its curvature, particle size, and particle density variations have all been investigated. To reveal how the nature of the temporal correlations (hydrodynamic memory) in the inertial regime is altered by the full hydrodynamic interactio...

  10. Experimental Motion Analysis of Radially Rotating Beams Using High-Speed Camera and Motion Analyzer

    Directory of Open Access Journals (Sweden)

    K.H. Low

    1996-01-01

    Full Text Available Although strain gauges can be attached to a system for vibration analysis, wires connected to the strain gauges may disturb the system and affect the accuracy of the strain measurement. As an alternative, this work presents the use of a high-speed camera combined with a motion analyzer to study the motion of rotating flexible beams. One end of the beam is rigidly connected to a motor, while the other end is free. White stickers placed on selected points on a given beam are the reference points in a digitization process. The modes of the vibrating beams can be filmed and analyzed. The vibration parameters, such as deflection and frequency, can be obtained by using a film motion analyzer. The results show that the beam does not behave in a clamped-free or a pinned-free fashion, but instead occurs at an intermediate boundary between these two classical conditions.

  11. The Transient MHD Flow Generated by a PeriodicWall Motion in a Porous Space

    Directory of Open Access Journals (Sweden)

    Mohammed Abdulhameed

    2016-01-01

    Full Text Available The problem of transient flow of incompressible third grade fluid on the two-dimensional magnetohydrodynamic (MHD flow in a porous space is analyzed. The flow is generated due to the motion of the plate in its plane with a periodic velocity. Under the flow assumptions, the governing nonlinear partial differential equation is transformed into steady-state and transient nonlinear equations. The reduced equation for the transient flow is solved analytically using symmetry approach while the nonlinear steady-state equation is solved using a modified version of He’s homotopy perturbation method. The effect of several operating parameters on the flow hydromagnetic is discussed. The results indicated that for the considered case, t = 1:5 is the moment after which the time-dependent transient motion of the fluid can be approximated with the steady-state motion, described by the steady-state solution. It is clear that, after this value of time t the time-dependent transient solution can be neglected.

  12. 2D-immunoblotting analysis of Sporothrix schenckii cell wall

    Directory of Open Access Journals (Sweden)

    Estela Ruiz-Baca

    2011-03-01

    Full Text Available We utilized two-dimensional gel electrophoresis and immunoblotting (2D-immunoblotting with anti-Sporothrix schenckii antibodies to identify antigenic proteins in cell wall preparations obtained from the mycelial and yeast-like morphologies of the fungus. Results showed that a 70-kDa glycoprotein (Gp70 was the major antigen detected in the cell wall of both morphologies and that a 60-kDa glycoprotein was present only in yeast-like cells. In addition to the Gp70, the wall from filament cells showed four proteins with molecular weights of 48, 55, 66 and 67 kDa, some of which exhibited several isoforms. To our knowledge, this is the first 2D-immunoblotting analysis of the S. schenckii cell wall.

  13. Stereo Scene Flow for 3D Motion Analysis

    CERN Document Server

    Wedel, Andreas

    2011-01-01

    This book presents methods for estimating optical flow and scene flow motion with high accuracy, focusing on the practical application of these methods in camera-based driver assistance systems. Clearly and logically structured, the book builds from basic themes to more advanced concepts, culminating in the development of a novel, accurate and robust optic flow method. Features: reviews the major advances in motion estimation and motion analysis, and the latest progress of dense optical flow algorithms; investigates the use of residual images for optical flow; examines methods for deriving mot

  14. Analysis and Modelling of Muscles Motion during Whole Body Vibration

    Directory of Open Access Journals (Sweden)

    La Gatta A

    2010-01-01

    Full Text Available The aim of the study is to characterize the local muscles motion in individuals undergoing whole body mechanical stimulation. In this study we aim also to evaluate how subject positioning modifies vibration dumping, altering local mechanical stimulus. Vibrations were delivered to subjects by the use of a vibrating platform, while stimulation frequency was increased linearly from 15 to 60 Hz. Two different subject postures were here analysed. Platform and muscles motion were monitored using tiny MEMS accelerometers; a contra lateral analysis was also presented. Muscle motion analysis revealed typical displacement trajectories: motion components were found not to be purely sinusoidal neither in phase to each other. Results also revealed a mechanical resonant-like behaviour at some muscles, similar to a second-order system response. Resonance frequencies and dumping factors depended on subject and his positioning. Proper mechanical stimulation can maximize muscle spindle solicitation, which may produce a more effective muscle activation.

  15. Structural analysis of cell wall polysaccharides using PACE

    Energy Technology Data Exchange (ETDEWEB)

    Mortimer, Jennifer C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Institute

    2017-01-01

    The plant cell wall is composed of many complex polysaccharides. The composition and structure of the polysaccharides affect various cell properties including cell shape, cell function and cell adhesion. Many techniques to characterize polysaccharide structure are complicated, requiring expensive equipment and specialized operators e.g. NMR, MALDI-MS. PACE (Polysaccharide Analysis using Carbohydrate gel Electrophoresis) uses a simple, rapid technique to analyze polysaccharide quantity and structure (Goubet et al. 2002). Whilst the method here describes xylan analysis, it can be applied (by use of the appropriate glycosyl hydrolase) to any cell wall polysaccharide.

  16. An in vitro comparative study of intracanal fluid motion and wall shear stress induced by ultrasonic and polymer rotary finishing files in a simulated root canal model.

    Science.gov (United States)

    Koch, Jon; Borg, John; Mattson, Abby; Olsen, Kris; Bahcall, James

    2012-01-01

    Objective. This in vitro study compared the flow pattern and shear stress of an irrigant induced by ultrasonic and polymer rotary finishing file activation in an acrylic root canal model. Flow visualization analysis was performed using an acrylic canal filled with a mixture of distilled water and rheoscopic fluid. The ultrasonic and polymer rotary finishing file were separately tested in the canal and activated in a static position and in a cyclical axial motion (up and down). Particle movement in the fluid was captured using a high-speed digital camera and DaVis 7.1 software. The fluid shear stress analysis was performed using hot film anemometry. A hot-wire was placed in an acrylic root canal and the canal was filled with distilled water. The ultrasonic and polymer rotary finishing files were separately tested in a static position and in a cyclical axial motion. Positive needle irrigation was also tested separately for fluid shear stress. The induced wall shear stress was measured using LabVIEW 8.0 software.

  17. The unsteady flow of a third-grade fluid caused by the periodic motion of an infinite wall with transpiration

    Directory of Open Access Journals (Sweden)

    M. Abdulhameed

    2015-12-01

    Full Text Available In this work, the unidirectional flow of an incompressible electrically conducting third-grade fluid past a vertical transpiration wall through a porous medium with time-dependent periodic motion is presented. The nonlinear partial differential equations are transformed to ordinary differential equation by means of symmetry reductions. The reduced equation is then solved analytically for steady-state and time-dependent transient parts. The time series of the transient flow velocity for different pertinent parameters are examined through plots. During the course of computation, it was observed that the time-dependent transient and steady-state solutions agree very well at large value of time when the ratio is related to fluid parameters γ∗γ>1.

  18. Small-scale deflagration cylinder test with velocimetry wall-motion diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Hooks, Daniel E [Los Alamos National Laboratory; Hill, Larry G [Los Alamos National Laboratory; Pierce, Timothy H [Los Alamos National Laboratory

    2010-01-01

    Predicting the likelihood and effects of outcomes resultant from thermal initiation of explosives remains a significant challenge. For certain explosive formulations, the general outcome can be broadly predicted given knowledge of certain conditions. However, there remain unexplained violent events, and increased statistical understanding of outcomes as a function of many variables, or 'violence categorization,' is needed. Additionally, the development of an equation of state equivalent for deflagration would be very useful in predicting possible detailed event consequences using traditional hydrodynamic detonation moders. For violence categorization, it is desirable that testing be efficient, such that it is possible to statistically define outcomes reliant on the processes of initiation of deflagration, steady state deflagration, and deflagration to detonation transitions. If the test simultaneously acquires information to inform models of violent deflagration events, overall predictive capabilities for event likelihood and consequence might improve remarkably. In this paper we describe an economical scaled deflagration cylinder test. The cyclotetramethylene tetranitramine (HMX) based explosive formu1lation PBX 9501 was tested using different temperature profiles in a thick-walled copper cylindrical confiner. This test is a scaled version of a recently demonstrated deflagration cylinder test, and is similar to several other thermal explosion tests. The primary difference is the passive velocimetry diagnostic, which enables measurement of confinement vessel wall velocities at failure, regardless of the timing and location of ignition.

  19. Field-induced domain wall motion of amorphous [CoSiB/Pt]{sub N} multilayers with perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Y. H.; Lee, K. J.; Jung, M. H., E-mail: mhjung@sogang.ac.kr [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Yoon, J. B.; Cho, J. H.; You, C.-Y. [Department of Physics, Inha University, Incheon 402-751 (Korea, Republic of); Kim, T. W. [Department of Advanced Materials Engineering, Sejong University, Seoul 143-747 (Korea, Republic of)

    2014-05-14

    Amorphous CoSiB/Pt multilayer is a perpendicular magnetic anisotropy material to achieve high squareness, low coercivity, strong anisotropy, and smooth domain wall (DW) motion, because of the smoother interface compared with crystalline multilayers. For [CoSiB(6 Å)/Pt (14 Å)]{sub N} multilayers with N = 3, 6, and 9, we studied the field-induced DW dynamics. The effective anisotropy constant K{sub 1}{sup eff} is 1.5 × 10{sup 6} erg/cm{sup 3} for all the N values, and the linear increment of coercive field H{sub c} with N gives constant exchange coupling J. By analyzing the field dependence of DW images at room temperature, a clear creep motion with the exponent μ = 1/4 could be observed. Even though the pinning field H{sub dep} slightly increases with N, the pinning potential energy U{sub c} is constant (=35 k{sub B}T) for all the N values. These results imply that the amorphous [CoSiB/Pt]{sub N} multilayers are inherently homogeneous compared to crystalline multilayers. For N ≤ 6, the pinning site density ρ{sub pin} is less than 1000/μm{sup 2}, which is about 1 pinning site per the typical device junction size of 30 × 30 nm{sup 2}. Also, the exchange stiffness constant A{sub ex} is obtained to be 0.48 × 10{sup −6} erg/cm, and the domain wall width is expected to be smaller than 5.5 nm. These results may be applicable for spin-transfer-torque magnetic random access memory and DW logic device applications.

  20. Analysis of myocardial motion using generalized spline models and tagged magnetic resonance images

    Science.gov (United States)

    Chen, Fang; Rose, Stephen E.; Wilson, Stephen J.; Veidt, Martin; Bennett, Cameron J.; Doddrell, David M.

    2000-06-01

    Heart wall motion abnormalities are the very sensitive indicators of common heart diseases, such as myocardial infarction and ischemia. Regional strain analysis is especially important in diagnosing local abnormalities and mechanical changes in the myocardium. In this work, we present a complete method for the analysis of cardiac motion and the evaluation of regional strain in the left ventricular wall. The method is based on the generalized spline models and tagged magnetic resonance images (MRI) of the left ventricle. The whole method combines dynamical tracking of tag deformation, simulating cardiac movement and accurately computing the regional strain distribution. More specifically, the analysis of cardiac motion is performed in three stages. Firstly, material points within the myocardium are tracked over time using a semi-automated snake-based tag tracking algorithm developed for this purpose. This procedure is repeated in three orthogonal axes so as to generate a set of one-dimensional sample measurements of the displacement field. The 3D-displacement field is then reconstructed from this sample set by using a generalized vector spline model. The spline reconstruction of the displacement field is explicitly expressed as a linear combination of a spline kernel function associated with each sample point and a polynomial term. Finally, the strain tensor (linear or nonlinear) with three direct components and three shear components is calculated by applying a differential operator directly to the displacement function. The proposed method is computationally effective and easy to perform on tagged MR images. The preliminary study has shown potential advantages of using this method for the analysis of myocardial motion and the quantification of regional strain.

  1. ALGORITHMS FOR TENNIS RACKET ANALYSIS BASED ON MOTION DATA

    Directory of Open Access Journals (Sweden)

    Maria Skublewska-Paszkowska

    2016-09-01

    Full Text Available Modern technologies, such as motion capture systems (both optical and markerless, are more and more frequently used for athlete performance analysis due to their great precision. Optical systems based on the retro-reflective markers allow for tracking motion of multiple objects of various types. These systems compute human kinetic and kinematic parameters based on biomechanical models. Tracking additional objects like a tennis racket is also a very important aspect for analysing the player’s technique and precision. The motion data gathered by motion capture systems may be used for analysing various aspects that may not be recognised by the human eye or a video camera. This paper presents algorithms for analysis of a tennis racket motion during two of the most important tennis strokes: forehand and backhand. An optical Vicon system was used for obtaining the motion data which was the input for the algorithms. They indicate: the velocity of a tennis racket’s head and the racket’s handle based on the trajectories of attached markers as well as the racket’s orientation. The algorithms were implemented and tested on the data obtained from a professional trainer who participated in the research and performed a series of ten strikes, separately for: 1 forehand without a ball, 2 backhand without a ball, 3 forehand with a ball and 4 backhand with a ball. The computed parameters are gathered in tables and visualised in a graph.

  2. Characteristic dynamic modes and domain-wall motion in magnetic nanotubes excited by resonant rotating magnetic fields

    Science.gov (United States)

    Yang, Jaehak; Kim, Junhoe; Kim, Bosung; Cho, Young-Jun; Lee, Jae-Hyeok; Kim, Sang-Koog

    2016-07-01

    We performed micromagnetic numerical calculations to explore a cylindrical nanotube's magnetization dynamics and domain-wall (DW) motions driven by eigen-circular-rotating magnetic fields of different frequencies. We discovered the presence of two different localized DW oscillations as well as asymmetric ferromagnetic resonance precession and azimuthal spin-wave modes at the corresponding resonant frequencies of the circular-rotating fields. Associated with these intrinsic modes, there exist very contrasting DW motions of different speed and propagation direction for a given DW chirality. The direction and speed of the DW propagation were found to be controllable according to the rotation sense and frequency of noncontact circular-rotating fields. Furthermore, spin-wave emissions from the moving DW were observed at a specific field frequency along with their Doppler effect. This work furthers the fundamental understanding of soft magnetic nanotubes' intrinsic dynamic modes and spin-wave emissions and offers an efficient means of manipulating the speed and direction of their DW propagations.

  3. wall

    Directory of Open Access Journals (Sweden)

    Irshad Kashif

    2016-01-01

    Full Text Available Maintaining indoor climatic conditions of buildings compatible with the occupant comfort by consuming minimum energy, especially in a tropical climate becomes a challenging problem for researchers. This paper aims to investigate this problem by evaluating the effect of different kind of Photovoltaic Trombe wall system (PV-TW on thermal comfort, energy consumption and CO2 emission. A detailed simulation model of a single room building integrated with PV-TW was modelled using TRNSYS software. Results show that 14-35% PMV index and 26-38% PPD index reduces as system shifted from SPV-TW to DGPV-TW as compared to normal buildings. Thermal comfort indexes (PMV and PPD lie in the recommended range of ASHARE for both DPV-TW and DGPV-TW except for the few months when RH%, solar radiation intensity and ambient temperature were high. Moreover PVTW system significantly reduces energy consumption and CO2 emission of the building and also 2-4.8 °C of temperature differences between indoor and outdoor climate of building was examined.

  4. Effect of a pinning field on the critical current density for current-induced domain wall motion in perpendicular magnetic anisotropy nanowires.

    Science.gov (United States)

    Ooba, Ayaka; Fujimura, Yuma; Takahashi, Kota; Komine, Takashi; Sugita, Ryuji

    2012-09-01

    In this study, the effect of a pinning field on the critical current density for current-induced domain wall motion in nanowires with perpendicular magnetic anisotropy was investigated using micromagnetic simulations. In order to estimate the pinning field in notched nanowires, we conducted wall energy calculations for nanowires with various saturation magnetizations. The pinning field increased as the notch size increased. The pinning field decreased as the saturation magnetization decreased. As a result, the decreased in the pinning field causes the reduction of the critical current density. Therefore, a significant reduction of the critical current density can be obtained by decreasing the saturation magnetization, even if wall pinning occurs.

  5. Time-motion analysis of elite male kickboxing competition

    OpenAIRE

    Ouergui, Ibrahim; Hssin, Nizar; Haddad, Monoem; Franchini, Emerson; BEHM, David G; Wong, Del P; Gmada, Nabil; Bouhlel, Ezzedine

    2014-01-01

    Time-motion analysis of elite male kickboxing competition. J Strength Cond Res 28(12): 3537–3543, 2014—The objective of the study was to analyze the time structure of high-level kickboxing matches. A total of 45 combats from 2 male World Championships were monitored using a time-motion analysis system. The combat time structure (i.e., high-intensity activity [HIA], low-intensity activity [LIA], and referee breaks or pauses) during competition and weight divisions was determined and compared. ...

  6. Recurrence plots and recurrence quantification analysis of human motion data

    Science.gov (United States)

    Josiński, Henryk; Michalczuk, Agnieszka; Świtoński, Adam; Szczesna, Agnieszka; Wojciechowski, Konrad

    2016-06-01

    The authors present exemplary application of recurrence plots, cross recurrence plots and recurrence quantification analysis for the purpose of exploration of experimental time series describing selected aspects of human motion. Time series were extracted from treadmill gait sequences which were recorded in the Human Motion Laboratory (HML) of the Polish-Japanese Academy of Information Technology in Bytom, Poland by means of the Vicon system. Analysis was focused on the time series representing movements of hip, knee, ankle and wrist joints in the sagittal plane.

  7. Time-motion analysis of elite male kickboxing competition

    OpenAIRE

    Ouergui, Ibrahim; Hssin, Nizar; Haddad, Monoem; Franchini, Emerson; David G. Behm; Wong, Del P.; Gmada, Nabil; Bouhlel, Ezzedine

    2014-01-01

    Time-motion analysis of elite male kickboxing competition. J Strength Cond Res 28(12): 3537–3543, 2014—The objective of the study was to analyze the time structure of high-level kickboxing matches. A total of 45 combats from 2 male World Championships were monitored using a time-motion analysis system. The combat time structure (i.e., high-intensity activity [HIA], low-intensity activity [LIA], and referee breaks or pauses) during competition and weight divisions was determined and compared. ...

  8. Analysis of heat transfer from single wires close to walls

    Science.gov (United States)

    Shi, J.-M.; Gerlach, D.; Breuer, M.; Durst, F.; Lange, C. F.

    2003-04-01

    Two-dimensional numerical investigations of the forced heat convection from a microcylinder in laminar cross-flow, both in free stream and in near-wall flow, were carried out aiming at a better understanding of the physics behind the wall effects on hot-wire near-wall measurements. In the physical model, an infinitely thin plate with the same properties as the fluid (air) was used as an artificial wall. The conjugate heat transfer between the flow regions on both sides of the plate was taken into account. The effect of the conjugate thermal conditions (temperature distribution and diffusive heat flux) at the interface of the two flow regions on the heat transfer from the wire was investigated by varying the flow conditions on the side opposite to the wire location. Careful energy balance analysis was performed for both the free-stream case and the near-wall case. This enabled the authors to verify their own understanding of the physical mechanism responsible for the wall effect on hot-wire measurements and to examine other mechanisms proposed in the literature. The numerical results showed that the heat diffusion from the wire is significantly enhanced in the case of small wire-to-wall distances (Y+convection) was shown not to be the most important influencing factor for the heat transfer of a hot wire. Although the present model study was performed for a laminar flow, the results obtained are applicable to hot-wire measurements in turbulent flows, as stated in the literature.

  9. Analysis of Roman wall paintings found in Verona.

    Science.gov (United States)

    Mazzocchin, Gian Antonio; Rudello, Danilo; Murgia, Emanuela

    2007-09-01

    The present paper deals with the analysis of roman wall paintings fragments recovered from twelve buildings of Verona, Italy. The analytical techniques used were Optical Microscopy, Scanning Electron Microscopy (SEM) equipped with an EDS microanalysis detector, Xray powder diffraction (XRD) Fourier Transform infrared spectroscopy (FTIR) and Raman Spectroscopy. The wall preparation generally consisted of three layer: the pictorial layer, an intonachino layer of hydrated lime and a plaster one made of slaked lime and sand. The pigments found in the studied domus are different reflecting the taste and culture of Xa Regio of Italy but also the economical possibilities of the dominus and the building period.

  10. Slow Motion of a Sphere Away from a Wall: Effect of Surface Roughness on the Viscous Force

    Indian Academy of Sciences (India)

    Sunil Datta; Manju Shukla

    2002-11-01

    An asymptotic analysis is given for the effect of roughness exhibited through the slip parameter on the motion of the sphere, moving away from a plane surface with velocity . The method replaces the no-slip condition at the rough surface by slip condition and employs the method of inner and outer regions on the sphere surface. For > 0, we have the classical slip boundary condition and the results of the paper are then of interest in the microprocessor industry.

  11. Interaction of Streamwise and Wall-Normal Velocities in Combined Wave-Current Motion

    Institute of Scientific and Technical Information of China (English)

    Shu-Qing YANG; In-Soo KIM; Daniel S. KOH; Young-Chae SONG

    2005-01-01

    The aim of this paper is to present an analytical expression for the streamwise velocity distribution in a non-uniform flow in the presence of waves; the correlation between the horizontal and vertical velocity components has been comprehensively examined. Different from previous researches which attributed the deviation of velocity from the classical log-law to the wave Reynolds stress, i.e. -ρ(uv)only, this study demonstrates that the momentum flux caused by mean velocities, i.e.,(u)and(v) , is also responsible for the velocity deviation, and it is found that the streamwise velocity for a flow in the presence of non-zero wall-normal velocity does not follow the classical log-law, but the modified log-law proposed in this study based on simplified mixing-length theorem. The validity of the modified log-law has been verified by use of available experimental data from published sources for combined wave-current flows, and good agreement between the predicted and observed velocity profiles has been achieved.

  12. Separating spin torque and heating effects in current-induced domain wall motion probed by high-resolution transmission electron microscopy

    DEFF Research Database (Denmark)

    Junginger, F.; Klaeui, M.; Backes, D.

    2007-01-01

    Observations of domain wall motion and transformations due to injected current pulses in permalloy zigzag structures using off-axis electron holography and Lorentz microscopy are reported. Heating on membranes leads to thermally activated random behavior at low current densities and by backcoating...

  13. Analysis of indoor rowing motion using wearable inertial sensors

    NARCIS (Netherlands)

    Bosch, Stephan; Shoaib, Muhammad; Geerlings, Stephen; Buit, Lennart; Meratnia, Nirvana; Havinga, Paul

    2015-01-01

    In this exploratory work the motion of rowers is analyzed while rowing on a rowing machine. This is performed using inertial sensors that measure the orientation at several positions on the body. Using these measurements, this work provides a preliminary analysis of the differences between experienc

  14. Detection of postischemic regional left ventricular delayed outward wall motion or diastolic stunning after exercise-induced ischemia in patients with stable effort angina by using color kinesis.

    Science.gov (United States)

    Ishii, Katsuhisa; Miwa, Kunihisa; Sakurai, Takahiro; Kataoka, Kazuaki; Imai, Makoto; Kintaka, Aya; Aoyama, Takeshi; Kawanami, Masaki

    2008-04-01

    To determine whether postischemic diastolic stunning could be detected using color kinesis, we evaluated regional left ventricular (LV) diastolic wall motion in 36 patients with stable effort angina and a coronary stenosis (> or = 70% of luminal diameter), and in 30 control subjects. Regional LV filling fraction in the short-axis view during the first 30% of the LV filling time (color kinesis diastolic index) was determined before, 20 minutes, 1 hour, and 24 hours after the treadmill exercise test. In 33 of the 36 patients (92%), new regional LV delayed outward motion during early diastole (color kinesis diastolic index < or = 40%) was detected at 20 minutes after exercise. The regional LV delayed diastolic wall motion showed significant improvement but persisted 1 hour afterward in 20 of 36 patients (56%), and disappeared 24 hours after exercise. Detection of regional stunned myocardium with impaired diastolic function may be a useful tool for the diagnosis of coronary artery disease.

  15. Analysis of shells of revolution under earthquake motion

    Energy Technology Data Exchange (ETDEWEB)

    Sheinman, I.

    1986-02-01

    A generalization of the solution of any shell of revolution under earthquake motion and dynamic loading is presented. The equations of motion are derived with the aid of Hamilton's variational principle. A numerical solution is obtained by expending the variables in a Fourier series in the circumferential and in finite elements in the meridional direction. For earthquake analysis an exact method based on step-by-step direct integration and an approximate one involving the spectral velocity, are compared. A case of a nuclear containment under a horizontal earthquake is considered by both methods as an example. (orig.).

  16. Machine Learning for Vision-Based Motion Analysis

    CERN Document Server

    Wang, Liang; Cheng, Li; Pietikainen, Matti

    2011-01-01

    Techniques of vision-based motion analysis aim to detect, track, identify, and generally understand the behavior of objects in image sequences. With the growth of video data in a wide range of applications from visual surveillance to human-machine interfaces, the ability to automatically analyze and understand object motions from video footage is of increasing importance. Among the latest developments in this field is the application of statistical machine learning algorithms for object tracking, activity modeling, and recognition. Developed from expert contributions to the first and second In

  17. Non-actual motion: phenomenological analysis and linguistic evidence.

    Science.gov (United States)

    Blomberg, Johan; Zlatev, Jordan

    2015-09-01

    Sentences with motion verbs describing static situations have been seen as evidence that language and cognition are geared toward dynamism and change (Talmy in Toward a cognitive semantics, MIT Press, Cambridge, 2000; Langacker in Concept, image, and symbol: the cognitive basis of grammar, Mouton de Gruyter, Berlin and New York, 1990). Different concepts have been used in the literature, e.g., fictive motion, subjective motion and abstract motion to denote this. Based on phenomenological analysis, we reinterpret such concepts as reflecting different motivations for the use of such constructions (Blomberg and Zlatev in Phenom Cogn Sci 13(3):395-418, 2014). To highlight the multifaceted character of the phenomenon, we propose the concept non-actual motion (NAM), which we argue is more compatible with the situated cognition approach than explanations such as "mental simulation" (e.g., Matlock in Studies in linguistic motivation, Mouton de Gruyter, Berlin, 2004). We investigate the expression of NAM by means of a picture-based elicitation task with speakers of Swedish, French and Thai. Pictures represented figures that either afford human motion or not (±afford); crossed with this, the figure extended either across the picture from a third-person perspective (3 pp) or from a first-person perspective (1 pp). All picture types elicited NAM-sentences with the combination [+afford, 1 pp] producing most NAM-sentences in all three languages. NAM-descriptions also conformed to language-specific patterns for the expression of actual motion. We conclude that NAM shows interaction between pre-linguistic motivations and language-specific conventions.

  18. Analysis of motion on agile shell-feeding system

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Since cannon drum of agile shell-feeding system rotates frequently and intermittently, its motion must be steady. Outline of driving cam determines the motion of cannon drum, so it is necessary to select the proper outline of cam. Through analysis of parabolic outline and cycloid outline of the cams, the outline that combines the two curves is obtained. According to the demand of production,the value of the outline is revised, and then the method of fitting curve is used to get the expression of the angle of cam and the displacement of the driven part. Through analyzing the motion of the cannon drum, it is suggested that the angle of the cam is proportion to the displacement of the driven part. The cam with the specially derived outline can move steadily.

  19. Ground Motion in Central Mexico: A Comprehensive Analysis

    Science.gov (United States)

    Ramirez-Guzman, L.; Juarez, A.; Rábade, S.; Aguirre, J.; Bielak, J.

    2015-12-01

    This study presents a detailed analysis of the ground motion in Central Mexico based on numerical simulations, as well as broadband and strong ground motion records. We describe and evaluate a velocity model for Central Mexico derived from noise and regional earthquake cross-correlations, which is used throughout this research to estimate the ground motion in the region. The 3D crustal model includes a geotechnical structure of the Valley of Mexico (VM), subduction zone geometry, and 3D velocity distributions. The latter are based on more than 200 low magnitude (Mw Valley of Mexico originating from intra-slab deep events and temblors located along the Pacific coast. Also, we quantify the effects Trans-Mexican Volcanic Belt (TMVB) and the low-velocity deposits on the ground motion. The 3D octree-based finite element wave propagation computations, valid up to 1 Hz, reveal that the inclusion of a basin with a structure as complex as the Valley of Mexico dramatically enhances the regional effects induced by the TMVB. Moreover, the basin not only produces ground motion amplification and anomalous duration, but it also favors the energy focusing into zones of Mexico City where structures typically undergo high levels of damage.

  20. Accuracy determination of camera system used for sport motion analysis

    Directory of Open Access Journals (Sweden)

    Bergün Meriç

    2008-10-01

    Full Text Available The aim of this study is to determine accuracy of camera system often used for motion analysis.       In order to accomplish this, an industrial robot was moved with known three different trajectories  and these motions were captured using three 100Hz cameras located in 3 different angles. Video data were digitized and analyzed using Simi Motion Analysis Program. With this program, angular kinematics were computed from the video data and compared with the data obtained from robot.       For considering analysis of the data, average error for angle computed from average values of absolute error and root values of average of squared error is is  0.92° and 1.33°, respectively. Similarly, average error for angular velocity computed from average values of absolute error and root values of average of squared error is is  0.77° and 0.96°, respectively.      These errors may result in the technique of image processing, shot speed of camera system and  the limited hand sensivity of users. As motions in sports were analyzed with the camera systems, these errors must be taken in account in kinematic computation.

  1. Accuracy determination of camera system used for sport motion analysis

    Directory of Open Access Journals (Sweden)

    Bergün Meriç

    2008-10-01

    Full Text Available The aim of this study is to determine accuracy of camera system often used for motion analysis. In order to accomplish this, an industrial robot was moved with known three different trajectories and these motions were captured using three 100Hz cameras located in 3 different angles. Video data were digitized and analyzed using Simi Motion Analysis Program. With this program, angular kinematics were computed from the video data and compared with the data obtained from robot. For considering analysis of the data, average error for angle computed from average values of absolute error and root values of average of squared error is is 0.92° and 1.33°, respectively. Similarly, average error for angular velocity computed from average values of absolute error and root values of average of squared error is is 0.77° and 0.96°, respectively. These errors may result in the technique of image processing, shot speed of camera system and the limited hand sensivity of users. As motions in sports were analyzed with the camera systems, these errors must be taken in account in kinematic computation.

  2. Cardiovascular magnetic resonance myocardial feature tracking detects quantitative wall motion during dobutamine stress.

    NARCIS (Netherlands)

    Schuster, A.; Kutty, S.; Padiyath, A.; Parish, V.; Gribben, P.; Danford, D.A.; Makowski, M.R.; Bigalke, B.; Beerbaum, P.B.J.; Nagel, E.

    2011-01-01

    BACKGROUND: Dobutamine stress cardiovascular magnetic resonance (DS-CMR) is an established tool to assess hibernating myocardium and ischemia. Analysis is typically based on visual assessment with considerable operator dependency. CMR myocardial feature tracking (CMR-FT) is a recently introduced tec

  3. Human Motion Video Analysis in Clinical Practice (Review)

    OpenAIRE

    V.V. Borzikov; N.N. Rukina; O.V. Vorobyova; A.N. Kuznetsov; A. N. Belova

    2015-01-01

    The development of new rehabilitation approaches to neurological and traumatological patients requires understanding of normal and pathological movement patterns. Biomechanical analysis of video images is the most accurate method of investigation and quantitative assessment of human normal and pathological locomotion. The review of currently available methods and systems of optical human motion analysis used in clinical practice is presented here. Short historical background is provi...

  4. Analytical solution of the strain-controlled magnetic domain wall motion in bilayer piezoelectric/magnetostrictive nanostructures

    Science.gov (United States)

    Consolo, Giancarlo; Valenti, Giovanna

    2017-01-01

    The one-dimensional propagation of magnetic domain walls in an isotropic, linearly elastic, magnetostrictive material is investigated in the framework of the extended Landau-Lifshitz-Gilbert equation where the effects of a spin-polarized current and a rate-independent dry-friction dissipation are taken into account. In our analysis, it is assumed that the ferromagnet is subject to a spatially uniform biaxial in-plain stress generated by a piezoelectric substrate combined with the former in a multiferroic heterostructure. Moreover, a possible connection between the dry-friction mechanism and the piezo-induced strains is conjectured. By adopting the traveling waves ansatz, the effect of such a stress on the domain wall dynamics is explored in both steady and precessional regimes. In particular, it is proved that the magnetoelastic contribution, while it does not formally modify the classical solution, affects both the propagation threshold and the Walker Breakdown conditions involved in the steady regime, in agreement with recent experimental results. In the precessional regime, it is shown that the existence of a correlation between the piezo-induced strains and dry-friction leads to an upward shift of the domain wall velocity.

  5. Linear Stability Analysis of Compressible Channel Flow with Porous Walls

    CERN Document Server

    Rahbari, Iman

    2015-01-01

    We have investigated the effects of permeable walls, modeled by linear acoustic impedance with zero reactance, on compressible channel flow via linear stability analysis (LSA). Base flow profiles are taken from impermeable isothermal-wall laminar and turbulent channel flow simulations at bulk Reynolds number, $Re_b$= 6900 and Mach numbers, $M_b$ = 0.2, 0.5, 0.85. For a sufficiently high value of permeability, two dominant modes are excited: a bulk pressure mode, causing symmetric expulsion and suction of mass from the porous walls (Mode 0); a standing-wave-like mode, with a pressure node at the centerline (Mode 1). In the case of turbulent mean flow profiles, both modes generate additional Reynolds shear stresses augmenting the (base) turbulent ones, but concentrated in the viscous sublayer region; the trajectories of the two modes in the complex phase velocity space follow each other very closely for values of wall permeability spanning two orders of magnitude, suggesting their coexistence. The transition fr...

  6. Preliminary Design and Analysis of ITER In-Wall Shielding

    Institute of Scientific and Technical Information of China (English)

    LIU Changle; YU Jie; WU Songtao; CAI Yingxiang; PAN Wanjiang

    2007-01-01

    ITER in-wall shielding (IIS) is situated between the doubled shells of the ITER Vacuum Vessel (IVV). Its main functions are applied in shielding neutron, gamma-ray and toroidal field ripple reduction. The structure of IIS has been modelled according to the IVV design criteria which has been updated by the ITER team (IT). Static analysis and thermal expansion analysis were performed for the structure. Thermal-hydraulic analysis verified the heat removal capability and resulting temperature, pressure, and velocity changes in the coolant flow. Consequently, our design work is possibly suitable as a reference for IT's updated or final design in its next step.

  7. Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Arepalli, Sivram; Nikolaev, Pavel; Gorelik, Olga

    2010-01-01

    An improved protocol for thermogravimetric analysis (TGA) of samples of single-wall carbon nanotube (SWCNT) material has been developed to increase the degree of consistency among results so that meaningful comparisons can be made among different samples. This improved TGA protocol is suitable for incorporation into the protocol for characterization of carbon nanotube material. In most cases, TGA of carbon nanotube materials is performed in gas mixtures that contain oxygen at various concentrations. The improved protocol is summarized.

  8. Equivalent Linearization of Polymer Matrix Composite Infill Wall Subjected to Seismic Ground Motions

    Directory of Open Access Journals (Sweden)

    BuSeog Ju

    2013-10-01

    Full Text Available Polymer Matrix Composite (PMC material was introduced as a new conceptual infill construction for seismic retrofitting. A proposed PMC-infilled system was composed of two basic structural components: inner PMC-infilled sandwich and outer FRP damping panels designed toconstrain the energy-dissipating layers. These two components along with the steel frame were intended for providing the desired stiffness and damping following different drift values. The observed behavior of the proposed PMC-infilled system was evaluated experimentally based on the stiffness, the mode of failure and the energy dissipation outputs. In this study, a piece-wise linear dynamic analysis for a proposed PMC-infilled frame was performed according to the previous research, for the assessment of their effectiveness and the responses under the simulated earthquake loading. Upon comparing the results of undamped (without PMC panel and damped (with PMC panel structures, numerical results showed that structural damping with passive interface damping layer could significantly enhance the seismic response. Furthermore, the numerical simulation response showed that the response of theequivalent linearized model produces more conservative results, in comparison to the response of piece-wise linear model.

  9. MR image analysis: Longitudinal cardiac motion influences left ventricular measurements

    Energy Technology Data Exchange (ETDEWEB)

    Berkovic, Patrick [University Hospital Antwerp, Department of Cardiology (Belgium)], E-mail: pberko17@hotmail.com; Hemmink, Maarten [University Hospital Antwerp, Department of Cardiology (Belgium)], E-mail: maartenhemmink@gmail.com; Parizel, Paul M. [University Hospital Antwerp, Department of Radiology (Belgium)], E-mail: paul.parizel@uza.be; Vrints, Christiaan J. [University Hospital Antwerp, Department of Cardiology (Belgium)], E-mail: chris.vrints@uza.be; Paelinck, Bernard P. [University Hospital Antwerp, Department of Cardiology (Belgium)], E-mail: Bernard.paelinck@uza.be

    2010-02-15

    Background: Software for the analysis of left ventricular (LV) volumes and mass using border detection in short-axis images only, is hampered by through-plane cardiac motion. Therefore we aimed to evaluate software that involves longitudinal cardiac motion. Methods: Twenty-three consecutive patients underwent 1.5-Tesla cine magnetic resonance (MR) imaging of the entire heart in the long-axis and short-axis orientation with breath-hold steady-state free precession imaging. Offline analysis was performed using software that uses short-axis images (Medis MASS) and software that includes two-chamber and four-chamber images to involve longitudinal LV expansion and shortening (CAAS-MRV). Intraobserver and interobserver reproducibility was assessed by using Bland-Altman analysis. Results: Compared with MASS software, CAAS-MRV resulted in significantly smaller end-diastolic (156 {+-} 48 ml versus 167 {+-} 52 ml, p = 0.001) and end-systolic LV volumes (79 {+-} 48 ml versus 94 {+-} 52 ml, p < 0.001). In addition, CAAS-MRV resulted in higher LV ejection fraction (52 {+-} 14% versus 46 {+-} 13%, p < 0.001) and calculated LV mass (154 {+-} 52 g versus 142 {+-} 52 g, p = 0.004). Intraobserver and interobserver limits of agreement were similar for both methods. Conclusion: MR analysis of LV volumes and mass involving long-axis LV motion is a highly reproducible method, resulting in smaller LV volumes, higher ejection fraction and calculated LV mass.

  10. Reliability analysis of retaining walls with multiple failure modes

    Institute of Scientific and Technical Information of China (English)

    张道兵; 孙志彬; 朱川曲

    2013-01-01

    In order to reduce the errors of the reliability of the retaining wall structure in the establishment of function, in the estimation of parameter and algorithm, firstly, two new reliability and stability models of anti-slipping and anti-overturning based on the upper-bound theory of limit analysis were established, and two kinds of failure modes were regarded as a series of systems with multiple correlated failure modes. Then, statistical characteristics of parameters of the retaining wall structure were inferred by maximal entropy principle. At last, the structural reliabilities of single failure mode and multiple failure modes were calculated by Monte Carlo method in MATLAB and the results were compared and analyzed on the sensitivity. It indicates that this method, with a high precision, is not only easy to program and quick in calculation, but also without the limit of nonlinear functions and non-normal random variables. And the results calculated by this method which applies both the limit analysis theory, maximal entropy principle and Monte Carlo method into analyzing the reliability of the retaining wall structures is more scientific, accurate and reliable, in comparison with those calculated by traditional method.

  11. Thermal analysis of ductile iron in thin walled casting

    Directory of Open Access Journals (Sweden)

    M. Górny

    2007-12-01

    Full Text Available Hypereutectic ductile iron was cast in self hardening moulding sand to produce castings with the shape of Archimedes spirals and with wall thickness of 1, 2 and 3 mm. Inmould technique was used to produce thin wall ductile iron (TWDI. In this work it has been carried out thermal analysis in spiral with 3 mm wall thickness. The present work provides results of thermal analysis, that are initial temperature of metal in mould cavity, velocity of metal stream as well as solidification time. Measurement of temperature shows that there is essential its drop during filling of mould cavity and amounts 230 oC for distance 700 mm from the beginning of spiral. On the basic on first derivative of temperature versus time characteristic solidification points were distinguish, namely solidification of primary graphite, austenite dendrite and eutectic. Experimental measurements of temperature drop during filling of mould cavity along with microscopic examinations of castings structure can be used to verify computer modeling and simulation of fluid flow and thermal field in TWDI.

  12. Controlling magnetic domain wall motion in the creep regime in He{sup +}-irradiated CoFeB/MgO films with perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Herrera Diez, L., E-mail: liza.herrera-diez@ief.u-psud.fr; García-Sánchez, F.; Adam, J.-P.; Devolder, T.; Eimer, S.; El Hadri, M. S.; Ravelosona, D. [Institut d' Electronique Fondamentale, Université Paris-Sud, UMR CNRS 8622, 91405 Orsay (France); Lamperti, A.; Mantovan, R. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate (MB) (Italy); Ocker, B. [Singulus Technology AG, Hanauer Landstrasse 103, 63796 Kahl am Main (Germany)

    2015-07-20

    This study presents the effective tuning of perpendicular magnetic anisotropy in CoFeB/MgO thin films by He{sup +} ion irradiation and its effect on domain wall motion in a low field regime. Magnetic anisotropy and saturation magnetisation are found to decrease as a function of the irradiation dose which can be related to the observed irradiation-induced changes in stoichiometry at the CoFeB/MgO interface. These changes in the magnetic intrinsic properties of the film are reflected in the domain wall dynamics at low magnetic fields (H) where irradiation is found to induce a significant decrease in domain wall velocity (v). For all irradiation doses, domain wall velocities at low fields are well described by a creep law, where Ln(v) vs. H{sup −1∕4} behaves linearly, up to a maximum field H*, which has been considered as an approximation to the value of the depinning field H{sub dep}. In turn, H* ≈ H{sub dep} is seen to increase as a function of the irradiation dose, indicating an irradiation-induced extension of the creep regime of domain wall motion.

  13. Stress analysis for wall structure in mobile hot cell design

    Energy Technology Data Exchange (ETDEWEB)

    Bahrin, Muhammad Hannan, E-mail: hannan@nuclearmalaysia.gov.my; Rahman, Anwar Abdul, E-mail: anwar@nuclearmalaysia.gov.my; Hamzah, Mohd Arif, E-mail: arif@nuclearmalaysia.gov.my; Mamat, Mohd Rizal; Azman, Azraf; Hasan, Hasni [Prototype and Plant Development Centre, Technical Services Division, Malaysian Nuclear Agency (Malaysia)

    2016-01-22

    Malaysian Nuclear Agency is developing a Mobile Hot Cell (MHC) in order to handle and manage Spent High Activity Radioactive Sources (SHARS) such as teletherapy heads and irradiators. At present, there are only two units of MHC in the world, in South Africa and China. Malaysian Mobile Hot cell is developed by Malaysian Nuclear Agency with the assistance of IAEA expert, based on the design of South Africa and China, but with improved features. Stress analysis has been performed on the design in order to fulfil the safety requirement in operation of MHC. This paper discusses the loading analysis effect from the sand to the MHC wall structure.

  14. Assessment of global und regional left ventricular function with a 16-slice spiral-CT using two different software tools for quantitative functional analysis and qualitative evaluation of wall motion changes in comparison with magnetic resonance imaging; Moeglichkeiten der 16-Schicht-CT bei der linksventrikulaeren Funktionsbestimmung: Beurteilung zweier unterschiedlicher Software-Tools zur quantitativen Funktionsanalyse sowie qualitative Bewertung von Wandbewegungsstoerungen im Vergleich zur Magnetresonanztomographie

    Energy Technology Data Exchange (ETDEWEB)

    Koch, K.; Oellig, F.; Kunz, P.; Bender, P.; Oberholzer, K.; Mildenberger, P.; Kreitner, K.F.; Thelen, M. [Klinik und Poliklinik fuer Radiologie, Johannes Gutenberg-Univ. Mainz (Germany); Hake, U. [Klinik fuer Herz-, Thorax- und Gefaesschirurgie, Johannes Gutenberg-Univ. Mainz (Germany)

    2004-12-01

    Purpose: To determine global and regional left ventricular (LV) function from retrospectively gated multidetector row computed tomography (CT) by using two different semiautomated analysis tools and to correlate the results with those of magnetic resonance imaging (MRI). Materials and Methods: Nineteen patients (5 females, 14males, mean age 69 years) underwent 16-slice spiral-CT (MS-CT) with standard technique without administration of {beta}-blockers for a decrease in the cardiac rate. Ten series of images were reconstructed at every 10% of the RR-interval. With commercially available software capable of semiautomated contour detection, end-diastolic and end-systolic LV volumes (EDV and ESV) were determined from short-axis multiplanar CT reformations (MPR). Axial images of the end-systolic and end-diastolic cardiac phase were transformed to 3D volumes (3D) to determine EDV and ESV by using a threshold-supported reconstruction algorithm dependent on the contrast enhancement of the left ventricle. Steady-state free-precession cine MR images were acquired in short-axis orientation on the same day in all but one patient. Regional wall motion was assessed qualitatively in 17 left ventricular segments and classified as normo-, hypo-, a- or dyskinetic. Bland-Altman analysis was performed to calculate limits of agreement and systematic errors between CT and MRI. Results: For MPR/3D, mean end-diastolic (144.4/142.8 mL {+-} 67.5/67.1) and end-systolic (66.4/68.7 mL {+-} 52.1/49.9) LV volumes as determined with MS-CT correlated well with MRI measurements (147.6 mL {+-} 67.6 [r = 0.98/0.96] and 73.3 mL {+-} 55.5 [r = 0.98/0.98], respectively [p <.001]). LV stroke volume (77.6/74.1 {+-} 19.2/23.4 mL for CT vs. 74.4 mL {+-} 13.4 for MRI, r = 0.92/0.74) and LV ejection fraction (58.6/55.9% {+-} 13.5/13.7 for CT vs. 55.6% {+-} 13.5 for MRI, r = 0.95/0.91) also showed good correlation (p<.001). Regional wall motion analysis revealed agreement between CT and MRI in 316/323 (97

  15. Wall Clutter Mitigation in Through-the-Wall Imaging Radar with Sparse Array Antenna Based on Independent Component Analysis

    Directory of Open Access Journals (Sweden)

    Zhang Chi

    2014-10-01

    Full Text Available For Through-the-Wall Imaging Radar (TWIR, wall clutter is critical for detecting target signals behind a wall. For a system with a sparse antenna array, the lack of observation channels makes it more difficult to separate the target signals and wall clutter. On the basis of fluctuation of the range profile in real transmit/receive channels, this paper proposes to use Independent Component Analysis (ICA on multiple down-range observations of each transmit/receive channel to remove the wall clutter. The simulation and experimental results show that the proposed method effectively separate target and clutter components, even though the signal-to-clutter ratio is only -30 dB.

  16. Analysis of strong ground motions to evaluate regional attenuation relationships

    Directory of Open Access Journals (Sweden)

    V. Montaldo

    2002-06-01

    Full Text Available Italian attenuation relationships at regional scale have been refined using a data set of 322 horizontal components of strong ground motions recorded mainly during the 1997-1998 Umbria-Marche, Central Italy, earthquake sequence. The data set includes records generated by events with local magnitude (M L ranging between 4.5 and 5.9, recorded at rock or soil sites and epicentral distance smaller than 100 km. Through a multiple step regression analysis, we calculated empirical equations for the peak ground acceleration and velocity, the Arias Intensity and for the horizontal components of the 5% damped velocity pseudo response spectra, corresponding to 14 frequencies ranging from 0.25 to 25 Hz. We compared our results with well known predictive equations, widely used on the national territory for Probabilistic Seismic Hazard Analysis. The results obtained in this study show smaller values for all the analyzed ground motion indicators compared to other predictive equations.

  17. Hydromagnetic couple-stress nanofluid flow over a moving convective wall: OHAM analysis

    Science.gov (United States)

    Awais, M.; Saleem, S.; Hayat, T.; Irum, S.

    2016-12-01

    This communication presents the magnetohydrodynamics (MHD) flow of a couple-stress nanofluid over a convective moving wall. The flow dynamics are analyzed in the boundary layer region. Convective cooling phenomenon combined with thermophoresis and Brownian motion effects has been discussed. Similarity transforms are utilized to convert the system of partial differential equations into coupled non-linear ordinary differential equation. Optimal homotopy analysis method (OHAM) is utilized and the concept of minimization is employed by defining the average squared residual errors. Effects of couple-stress parameter, convective cooling process parameter and energy enhancement parameters are displayed via graphs and discussed in detail. Various tables are also constructed to present the error analysis and a comparison of obtained results with the already published data. Stream lines are plotted showing a difference of Newtonian fluid model and couplestress fluid model.

  18. Assessment of competence in simulated flexible bronchoscopy using motion analysis

    DEFF Research Database (Denmark)

    Collela, Sara; Svendsen, Morten Bo Søndergaard; Konge, Lars

    2015-01-01

    Background: Flexible bronchoscopy should be performed with a correct posture and a straight scope to optimize bronchoscopy performance and at the same time minimize the risk of work-related injuries and endoscope damage. Objectives: We aimed to test whether an automatic motion analysis system could...... with the performance on the simulator (virtual-reality simulator score; p correct movements during self-directed training on simulators might help new bronchoscopists learn how to handle...

  19. Features Analysis of Dry Stone Walls of Tuscany (Italy

    Directory of Open Access Journals (Sweden)

    Mauro Agnoletti

    2015-10-01

    Full Text Available Terraced systems currently represent an indubitable added value for Tuscany, as well as for other Italian regions and for several Mediterranean countries. This value goes beyond their original function of hosting new areas for cultivation. The hydrological functions performed by these systems, including control of erosion, stabilisation of the slopes, prolongation of runoff times and the possible reduction of the volumes of surface runoff, are well-known. In addition, they also play a strategic role in the conservation of biodiversity and in maintaining local identity. At a national level, the terraced agricultural systems fall within the scope of actions scheduled in the National Strategic Plan for Rural Development 2007–2013, and the standards of Good Agricultural and Environmental Conditions (GAECs envisages that they be maintained through the granting of economic aid as laid down in the Rural Development Plans 2007–2013 and 2014–2020. Eighteen sample areas, previously selected on the basis of the terracing intensity index (defined as the ratio between the lines representing the walls and the surface of 1 ha, were subjected for on-site surveys to determine the geo-typological features through the identification and measurement of the main technical-construction parameters of the dry stone walls. This analysis also enabled assessments of the overall state of conservation of the dry stone walls in order to suggest operations for safeguarding and protection.

  20. Method for aortic wall strain measurement with three-dimensional ultrasound speckle tracking and fitted finite element analysis.

    Science.gov (United States)

    Karatolios, Konstantinos; Wittek, Andreas; Nwe, Thet Htar; Bihari, Peter; Shelke, Amit; Josef, Dennis; Schmitz-Rixen, Thomas; Geks, Josef; Maisch, Bernhard; Blase, Christopher; Moosdorf, Rainer; Vogt, Sebastian

    2013-11-01

    Aortic wall strains are indicators of biomechanical changes of the aorta due to aging or progressing pathologies such as aortic aneurysm. We investigated the potential of time-resolved three-dimensional ultrasonography coupled with speckle-tracking algorithms and finite element analysis as a novel method for noninvasive in vivo assessment of aortic wall strain. Three-dimensional volume datasets of 6 subjects without cardiovascular risk factors and 2 abdominal aortic aneurysms were acquired with a commercial real time three-dimensional echocardiography system. Longitudinal and circumferential strains were computed offline with high spatial resolution using a customized commercial speckle-tracking software and finite element analysis. Indices for spatial heterogeneity and systolic dyssynchrony were determined for healthy abdominal aortas and abdominal aneurysms. All examined aortic wall segments exhibited considerable heterogenous in-plane strain distributions. Higher spatial resolution of strain imaging resulted in the detection of significantly higher local peak strains (p ≤ 0.01). In comparison with healthy abdominal aortas, aneurysms showed reduced mean strains and increased spatial heterogeneity and more pronounced temporal dyssynchrony as well as delayed systole. Three-dimensional ultrasound speckle tracking enables the analysis of spatially highly resolved strain fields of the aortic wall and offers the potential to detect local aortic wall motion deformations and abnormalities. These data allow the definition of new indices by which the different biomechanical properties of healthy aortas and aortic aneurysms can be characterized. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  1. [Asynchronous wall motion in patients with ischemic heart disease assessed by higher-order harmonics of the Fourier series].

    Science.gov (United States)

    Kodama, S; Tamaki, N; Mukai, T; Yonekura, Y; Torizuka, K; Suzuki, Y; Tamaki, S; Nohara, R; Kambara, H; Kawai, C

    1986-01-01

    To assess regional cardiac function in patients with ischemic heart disease (IHD), multigated blood-pool studies using higher-order harmonics of the Fourier series were performed for 14 normal persons and 37 patients with IHD. IHD was further divided into IHD (I) (EF greater than or equal to 50%) and IHD (II) (EF less than 50%). A pixel-by-pixel volume curve was simulated using second order harmonics of the Fourier series to create functional images of the following parameters: time to endosystole (TES), peak ejection rate (PER), time to PER (TPE), peak filling rate (PFR), and time to PFR (TPF). TES (SD), TPE (SD), and TPF (SD) were calculated as the standard deviations of left ventricular (LV) histograms of each phase, representing indexes of asynchronous wall motion. An LV volume curve was simulated using third order harmonics to calculate PFR, PFR/PER, and TPF/TPE, representing indexes of diastolic function. TES (SD) was abnormal in 10 cases (50%), and TPE (SD) was abnormal in seven cases (35%) of IHD (II). On the contrary, TPF (SD) was abnormal in three cases (18%) of IHD (I) and 15 cases (75%) of IHD (II), indicating that diastolic asynchronous indexes are more sensitive than systolic asynchronous indexes in detecting IHD. IHD (I) and IHD (II) showed lower PFR (2.32 +/- 0.55, 1.64 +/- 0.46 EDV/sec) and lower PFR/PER (0.84 +/- 0.15, 0.68 +/- 0.26) than those in normals (3.25 +/- 0.98 EDV/sec, 0.99 +/- 0.19), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Analysis of the soluble cell wall proteome of gymnosperms.

    Science.gov (United States)

    Uzal, Esther Novo; Gómez-Ros, Laura V; Hernández, Jose A; Pedreño, María A; Cuello, Juan; Ros Barceló, Alfonso

    2009-05-15

    We analyzed the cell wall proteome of lignifying suspension cell cultures (SCCs) from four gymnosperms that differ in evolution degree. This analysis showed the presence of "peptide sequence tags" (PSTs) corresponding to glucan endo-1,3-beta-D-glucosidase, xyloglucan-endotrans-glucosylase/hydrolase, chitinases, thaumatin-like proteins and proteins involved in lignin/lignan biosynthesis, such as dirigent-like proteins and peroxidases. Surprisingly, and given the abundance of peroxidases in the cell wall proteome of these gymnosperms, PSTs corresponding to peroxidases were only detected in tryptic fragments of the cell wall proteome of Cycas revoluta. The current lack of knowledge regarding C. revoluta peroxidases led us to purify, characterize and partially sequence the peroxidases responsible for lignin biosynthesis in this species. This yielded three peroxidase-enriched fractions: CrPrx 1, CrPrx 2 and CrPrx 3. Analyses of tryptic peptides of CrPrx 2 (32kDa) and CrPrx 3 (26kDa) suggest that CrPrx 3 arises from CrPrx 2 by protein truncation, and that CrPrx 3 apparently constitutes a post-translational modification of CrPrx 2. That CrPrx 2 and CrPrx 3 are apparently the same enzyme was also deduced from the similarity between the k(cat) shown by both peroxidases for the three monolignols. These results emphasize the analogies between the cell wall proteome of gymnosperms and angiosperms, the complexity of the peroxidase proteome, and the difficulties involved in establishing fine structure-function relationships.

  3. Motion Simulation Analysis of Rail Weld CNC Fine Milling Machine

    Science.gov (United States)

    Mao, Huajie; Shu, Min; Li, Chao; Zhang, Baojun

    CNC fine milling machine is a new advanced equipment of rail weld precision machining with high precision, high efficiency, low environmental pollution and other technical advantages. The motion performance of this machine directly affects its machining accuracy and stability, which makes it an important consideration for its design. Based on the design drawings, this article completed 3D modeling of 60mm/kg rail weld CNC fine milling machine by using Solidworks. After that, the geometry was imported into Adams to finish the motion simulation analysis. The displacement, velocity, angular velocity and some other kinematical parameters curves of the main components were obtained in the post-processing and these are the scientific basis for the design and development for this machine.

  4. Current-driven domain wall motion due to volume spin transfer torque in Co/Ni multilayer systems on Au underlayer

    Science.gov (United States)

    Ryu, Kwang-Su; Yang, See-Hun; Thomas, Luc; Parkin, Stuart

    2016-09-01

    We have studied the current-induced domain wall (CIDW) dynamics in perpendicularly magnetized Co/Ni multilayers deposited on Au underlayer, where the conventional spin transfer torque governs the domain wall dynamics, by the Kerr microscope. It is found that the DW angle tilting following Oersted field profile plays an important role in domain wall (DW) motion at high current density J by decreasing DW velocity with the increasing J, while distorting its DW morphology. Also we find that the DW pinning becomes pronounced as the anisotropy decreases by increasing number of Co/Ni repeats. Most remarkably, the DW tilting angle changes its sign by inserting ultrathin Pt layer between Au and Co layer, which suggests that the Dzyaloshinskii-Moriya interaction and spin Hall effect induces opposite effect in DW tilting. Our findings can be of use for application of CIDW to spintronics with perpendicularly magnetized systems.

  5. Analysis of ground-motion simulation big data

    Science.gov (United States)

    Maeda, T.; Fujiwara, H.

    2016-12-01

    We developed a parallel distributed processing system which applies a big data analysis to the large-scale ground motion simulation data. The system uses ground-motion index values and earthquake scenario parameters as input. We used peak ground velocity value and velocity response spectra as the ground-motion index. The ground-motion index values are calculated from our simulation data. We used simulated long-period ground motion waveforms at about 80,000 meshes calculated by a three dimensional finite difference method based on 369 earthquake scenarios of a great earthquake in the Nankai Trough. These scenarios were constructed by considering the uncertainty of source model parameters such as source area, rupture starting point, asperity location, rupture velocity, fmax and slip function. We used these parameters as the earthquake scenario parameter. The system firstly carries out the clustering of the earthquake scenario in each mesh by the k-means method. The number of clusters is determined in advance using a hierarchical clustering by the Ward's method. The scenario clustering results are converted to the 1-D feature vector. The dimension of the feature vector is the number of scenario combination. If two scenarios belong to the same cluster the component of the feature vector is 1, and otherwise the component is 0. The feature vector shows a `response' of mesh to the assumed earthquake scenario group. Next, the system performs the clustering of the mesh by k-means method using the feature vector of each mesh previously obtained. Here the number of clusters is arbitrarily given. The clustering of scenarios and meshes are performed by parallel distributed processing with Hadoop and Spark, respectively. In this study, we divided the meshes into 20 clusters. The meshes in each cluster are geometrically concentrated. Thus this system can extract regions, in which the meshes have similar `response', as clusters. For each cluster, it is possible to determine

  6. Crystallographic analysis of the thermal motion of the inclusion complex of cyclomaltoheptaose (beta-cyclodextrin) with hexamethylenetetramine.

    Science.gov (United States)

    Harata, Kazuaki

    2003-02-07

    The crystal structure of the inclusion complex of cyclomaltoheptaose (beta-cyclodextrin) with hexamethylenetetramine was determined at temperatures of 123, 173, 223, and 293 K. The rigid-body motion of the host and guest molecules was evaluated by means of the TLS method that represents the molecular motion in terms of translation, libration, and screw motion. In increasing the temperature from 123 to 293 K, the amplitude of the rigid body vibration of the host molecule was increased from 1.0 to 1.3 degrees in the rotational motion and from 0.16 to 0.17 A in the translational motion. The cyclomaltoheptaose molecule has the flexibility in seven alpha-(1-->4)-linkages, and each glucose unit was in the rotational vibration around an axis through two glycosidic oxygen atoms. As a result, the rigid-body parameters of cyclomaltoheptaose were considered to be overestimated because of including the contribution from the local motion of glucose units. In contrast, for the guest molecule having no structural flexibility, the TLS analysis demonstrated that the atomic thermal vibration was mostly derived from the rigid body motion. The rotational amplitude of hexamethylenetetramine was changed from 5.2 to 6.6 degrees in increasing the temperature from 123 to 293 K, while the change of the translational amplitude was from 0.20 to 0.23 A. The translational motion of the guest molecule was hindered by the inside wall of the host cavity. The molecular motion was characterized by the rotational vibration around the axis through two nitrogen atoms that were involved in the hydrogen-bond formation.

  7. Fluid-structure interaction analysis of bioprosthetic heart valves: Significance of arterial wall deformation.

    Science.gov (United States)

    Hsu, Ming-Chen; Kamensky, David; Bazilevs, Yuri; Sacks, Michael S; Hughes, Thomas J R

    2014-10-01

    We propose a framework that combines variational immersed-boundary and arbitrary Lagrangian-Eulerian (ALE) methods for fluid-structure interaction (FSI) simulation of a bioprosthetic heart valve implanted in an artery that is allowed to deform in the model. We find that the variational immersed-boundary method for FSI remains robust and effective for heart valve analysis when the background fluid mesh undergoes deformations corresponding to the expansion and contraction of the elastic artery. Furthermore, the computations presented in this work show that the arterial wall deformation contributes significantly to the realism of the simulation results, leading to flow rates and valve motions that more closely resemble those observed in practice.

  8. Towards the mechanical characterization of abdominal wall by inverse analysis.

    Science.gov (United States)

    Simón-Allué, R; Calvo, B; Oberai, A A; Barbone, P E

    2017-02-01

    The aim of this study is to characterize the passive mechanical behaviour of abdominal wall in vivo in an animal model using only external cameras and numerical analysis. The main objective lies in defining a methodology that provides in vivo information of a specific patient without altering mechanical properties. It is demonstrated in the mechanical study of abdomen for hernia purposes. Mechanical tests consisted on pneumoperitoneum tests performed on New Zealand rabbits, where inner pressure was varied from 0mmHg to 12mmHg. Changes in the external abdominal surface were recorded and several points were tracked. Based on their coordinates we reconstructed a 3D finite element model of the abdominal wall, considering an incompressible hyperelastic material model defined by two parameters. The spatial distributions of these parameters (shear modulus and non linear parameter) were calculated by inverse analysis, using two different types of regularization: Total Variation Diminishing (TVD) and Tikhonov (H(1)). After solving the inverse problem, the distribution of the material parameters were obtained along the abdominal surface. Accuracy of the results was evaluated for the last level of pressure. Results revealed a higher value of the shear modulus in a wide stripe along the craneo-caudal direction, associated with the presence of linea alba in conjunction with fascias and rectus abdominis. Non linear parameter distribution was smoother and the location of higher values varied with the regularization type. Both regularizations proved to yield in an accurate predicted displacement field, but H(1) obtained a smoother material parameter distribution while TVD included some discontinuities. The methodology here presented was able to characterize in vivo the passive non linear mechanical response of the abdominal wall. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. 3D Guided Wave Motion Analysis on Laminated Composites

    Science.gov (United States)

    Tian, Zhenhua; Leckey, Cara; Yu, Lingyu

    2013-01-01

    Ultrasonic guided waves have proved useful for structural health monitoring (SHM) and nondestructive evaluation (NDE) due to their ability to propagate long distances with less energy loss compared to bulk waves and due to their sensitivity to small defects in the structure. Analysis of actively transmitted ultrasonic signals has long been used to detect and assess damage. However, there remain many challenging tasks for guided wave based SHM due to the complexity involved with propagating guided waves, especially in the case of composite materials. The multimodal nature of the ultrasonic guided waves complicates the related damage analysis. This paper presents results from parallel 3D elastodynamic finite integration technique (EFIT) simulations used to acquire 3D wave motion in the subject laminated carbon fiber reinforced polymer composites. The acquired 3D wave motion is then analyzed by frequency-wavenumber analysis to study the wave propagation and interaction in the composite laminate. The frequency-wavenumber analysis enables the study of individual modes and visualization of mode conversion. Delamination damage has been incorporated into the EFIT model to generate "damaged" data. The potential for damage detection in laminated composites is discussed in the end.

  10. The dynamics of the asymmetric motion of domain walls of sandwich domain structure in a Fe-based amorphous ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Zhmetko, D.N., E-mail: sergey.zhmetko@gmail.com [Department of Physics, Zaporizhzhya National University, 66 Zhukovsky Street, 69063 Zaporizhzhya (Ukraine); Zhmetko, S.D. [Department of Physics, Zaporizhzhya National University, 66 Zhukovsky Street, 69063 Zaporizhzhya (Ukraine); Troschenkov, Y.N. [Institute for Magnetism, 36-b Vernadsky Boulevard, 03142 Kyiv (Ukraine); Matsura, A.V. [Department of Physics, Zaporizhzhya National University, 66 Zhukovsky Street, 69063 Zaporizhzhya (Ukraine)

    2013-08-15

    The frequency dependence of asymmetry of the domain walls velocity relative to the middle plane of amorphous ribbon is investigated. An additional pressure of the same direction acting on each domain wall caused by dependence of eddy current damping on the coordinate of the domain wall is revealed. The microscopic mechanisms of this additional pressure are considered. - Highlights: ► Additional pressure on the domain wall, caused by inhomogeneity of its damping. ► Asymmetry of the coordinate of the nucleation of domain walls and their damping. ► Connection between the components of additional pressure and its direction. ► Interaction of domain walls with the surface defects of the amorphous ribbon.

  11. Analysis of Heald Motion During of Weaving Process

    Science.gov (United States)

    Bilek, M.

    The paper is concerned with description of the mathematical model meant for an analysis of the movement of healds during the weaving cycle. The referred model consists of mathematical description of shedding motion, coupled with the solution of the model of the heald of weaving loom. The effected calculations show a high value of acceleration of the heald produced after its drop upon the supporting wire. The referred model allows analysing a considerable part of designs of heald shaft that are employed in weaving looms nowadays.

  12. Analysis of Motion in Single-Point Mooring Systems

    Directory of Open Access Journals (Sweden)

    Hans R. Sørheim

    1980-07-01

    Full Text Available A mathematical model of the slow motions of ships in single-point moorings is described. The model is used for analysis of stability of equilibrium positions. An analytical criterion for stability relating main system parameters is derived under simplifying assumptions. A numerical example with a 100 000 dwt tanker showed that the effect of wind and current are of equal importance with respect to system stability, and astern propulsion is generally required to avoid stable oscillations. Stability problems in waves have not been found. The effects of time varying excitations are discussed and illustrated by simulation.

  13. An automated time and hand motion analysis based on planar motion capture extended to a virtual environment

    Science.gov (United States)

    Tinoco, Hector A.; Ovalle, Alex M.; Vargas, Carlos A.; Cardona, María J.

    2015-03-01

    In the context of industrial engineering, the predetermined time systems (PTS) play an important role in workplaces because inefficiencies are found in assembly processes that require manual manipulations. In this study, an approach is proposed with the aim to analyze time and motions in a manual process using a capture motion system embedded to a virtual environment. Capture motion system tracks IR passive markers located on the hands to take the positions of each one. For our purpose, a real workplace is virtually represented by domains to create a virtual workplace based on basic geometries. Motion captured data are combined with the virtual workplace to simulate operations carried out on it, and a time and motion analysis is completed by means of an algorithm. To test the methodology of analysis, a case study was intentionally designed using and violating the principles of motion economy. In the results, it was possible to observe where the hands never crossed as well as where the hands passed by the same place. In addition, the activities done in each zone were observed and some known deficiencies were identified in the distribution of the workplace by computational analysis. Using a frequency analysis of hand velocities, errors in the chosen assembly method were revealed showing differences in the hand velocities. An opportunity is seen to classify some quantifiable aspects that are not identified easily in a traditional time and motion analysis. The automated analysis is considered as the main contribution in this study. In the industrial context, a great application is perceived in terms of monitoring the workplace to analyze repeatability, PTS, workplace and labor activities redistribution using the proposed methodology.

  14. Quantitative image analysis for the detection of motion artefacts in coronary artery computed tomography

    NARCIS (Netherlands)

    Kristanto, Wisnumurti; van Ooijen, Peter M.; Dikkers, Riksta; Greuter, Marcel J.; Zijlstra, Felix; Oudkerk, Matthijs

    2010-01-01

    Multi detector-row CT (MDCT), the current preferred method for coronary artery disease assessment, is still affected by motion artefacts. To rule out motion artefacts, qualitative image analysis is usually performed. Our study aimed to develop a quantitative image analysis for motion artefacts detec

  15. Raman spectroscopic analysis of a belltower commemorative wall decoration

    Science.gov (United States)

    Fernandes, R. F.; de Oliveira, L. F. C.; Edwards, H. G. M.; Brooke, C. J.; Pepper, M.

    2017-02-01

    The Raman spectroscopic analysis of a rare wall decoration in a church belltower, depicting the initials of couples married there in circular roundels over some 230 years, since 1777, has been undertaken prior to their impending restoration. The spectral data indicate that the red pigment is exclusively haematite which has been applied to plaster which exhibits the signatures variously of calcite, gypsum, anhydrite, calcium phosphate and dolomitic limestone; evidence of amorphous carbon is attributed to the deposition of soot from candle illumination, which has been recorded in historical documentation. The presence of biosignatures attributed to carotenoids in several samples is evidence of biological colonisation and potential deterioration which requires special treatment in the restoration strategies. The blackened areas near the upper edges of the wall decoration indicate carbon deposition and organic contamination. The latest addition to the decoration accomplished in 2008 shows that haematite has been used over a calcite ground. In earlier dated specimens, the presence of limewash is evident, which has only been partially converted into calcite by aerial attack from carbon dioxide in moist conditions.

  16. Structural finite element analysis of ITER In-wall shield

    Energy Technology Data Exchange (ETDEWEB)

    Shaikh, Moinuddin S., E-mail: moins@iter-india.org [ITER-India, Institute for Plasma Research, A-29, GIDC Electronic Estate, Sector 25, Gandhinagar 382016 (India); Pathak, H.A. [ITER-India, Institute for Plasma Research, A-29, GIDC Electronic Estate, Sector 25, Gandhinagar 382016 (India); Oliver, Tailhardat [Assystem EOS, Zac Saint Martin, 23 Rue Benjamin Franklin, 84120 Pertuis (France); Wang, Xiaoyu [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2013-10-15

    The In-wall shielding (IWS) located between two shells of the vacuum vessel is part of the vacuum vessel of ITER. The function of the IWS is to provide neutron shielding and to reduce toroidal field ripple. The IWS plates are fastened using M30 bolts to hold them securely and the IWS blocks are mounted to the support ribs using the brackets and M20 bolts. The paper presents a structural finite element analysis of one sample IWS block carried out using ANSYS* to establish the benchmark analysis procedure of the IWS blocks. Boundary conditions are set taking into account the assembly procedure of the IWS blocks. The analysis is carried out in three load steps (1). Pretension on M30 (2). Pretension on M30 and M20 and (3) pretension on M30 and M20 plus Electromagnetic forces, dynamic forces, Seismic forces, etc. The stresses and displacements of individual IWS components are evaluated against their allowable stress limits as per an ASME guideline. The ITER-India’s results of analysis are compared with the ITER-IO’s results for the worst category 3-load step 3 and they are found comparable. This establishes the analysis procedure to be used for all of the IWS blocks.

  17. Camera systems in human motion analysis for biomedical applications

    Science.gov (United States)

    Chin, Lim Chee; Basah, Shafriza Nisha; Yaacob, Sazali; Juan, Yeap Ewe; Kadir, Aida Khairunnisaa Ab.

    2015-05-01

    Human Motion Analysis (HMA) system has been one of the major interests among researchers in the field of computer vision, artificial intelligence and biomedical engineering and sciences. This is due to its wide and promising biomedical applications, namely, bio-instrumentation for human computer interfacing and surveillance system for monitoring human behaviour as well as analysis of biomedical signal and image processing for diagnosis and rehabilitation applications. This paper provides an extensive review of the camera system of HMA, its taxonomy, including camera types, camera calibration and camera configuration. The review focused on evaluating the camera system consideration of the HMA system specifically for biomedical applications. This review is important as it provides guidelines and recommendation for researchers and practitioners in selecting a camera system of the HMA system for biomedical applications.

  18. Analysis of pigments from Roman wall paintings found in Vicenza.

    Science.gov (United States)

    Mazzocchin, G A; Agnoli, F; Mazzocchin, S; Colpo, I

    2003-11-12

    The analysis of about 60 samples of wall paintings was carried out using different chemicophysical techniques: optical microscopy, scanning electron microscopy (SEM) equipped with an EDS microanalysis detector, X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The identified pigments were cinnabar, hematite, red ochre, celadonite, cuprorivaite (Egyptian blue), yellow ochre, goethite and carbon. Only in one case some lead white was found instead. In general, the mortar preparation did not correspond to the complex structure suggested by Vitruvius (De Architectura), but it generally showed a porous layer, with crushed grains under the pigment layer. In certain cases two superposed pigment layers were found: yellow superimposed on both red and pink, black on pink, green on black.

  19. Integration of monocular motion signals and the analysis of interocular velocity differences for the perception of motion-in-depth.

    Science.gov (United States)

    Shioiri, Satoshi; Kakehi, Daisuke; Tashiro, Tomoyoshi; Yaguchi, Hirohisa

    2009-12-09

    We investigated how the mechanism for perceiving motion-in-depth based on interocular velocity differences (IOVDs) integrates signals from the motion spatial frequency (SF) channels. We focused on the question whether this integration is implemented before or after the comparison of the velocity signals from the two eyes. We measured spatial frequency selectivity of the MAE of motion in depth (3D MAE). The 3D MAE showed little spatial frequency selectivity, whereas the 2D lateral MAE showed clear spatial frequency selectivity in the same condition. This indicates that the outputs of the monocular motion SF channels are combined before analyzing the IOVD. The presumption was confirmed by the disappearance of the 3D MAE after exposure to superimposed gratings with different spatial frequencies moving in opposite directions. The direction of the 2D MAE depended on the test spatial frequency in the same condition. These results suggest that the IOVD is calculated at a relatively later stage of the motion analysis, and that some monocular information is preserved even after the integration of the motion SF channel outputs.

  20. Penetrating a wall of introspection: a critical attrition analysis

    Science.gov (United States)

    Johannsen, Bjørn Friis; Rump, Camilla Østerberg; Linder, Cedric

    2013-03-01

    This paper presents a critical analysis of student discourse on attrition as it unfolds in interviews on early departure from higher education. A synthesis of relevant studies and modelling done in the field shows that essential aspects affecting attrition and retention can be effectively conceptualized and acted upon in terms of the interplay between student and institution. These aspects were used in combination with James Gee's notion of Discourse models to design a unique framing for interpretation of interviews aimed at bringing out new causal dynamics that lie in this interplay. To illustrate this interpretation, Aristotle's notion of four causes is used. The analysis presented is a study of interviews with seven former physics students about their early departure. This framing of the analysis was necessary because the students' description of how they understood their actions did not explicitly reveal interplay between student and institution. These details lay behind a `wall of introspection' that otherwise posed a serious challenge to the use of student testimony as direct means to identify and address issues of early departure. The results are used to discuss research implications.

  1. Analysis of superheater's pipe wall overtemperature by fault tree diagnose

    Institute of Scientific and Technical Information of China (English)

    盛德仁; 任浩仁; 陈坚红; 李蔚

    2002-01-01

    After research on a 2000t/h subcritical forced-circulation balanced v entilation were applied boiler and the structure and operation of its auxiliary system builds up this heat transfer model of a superheater's pipe wall and analy ze the effect of primary factors on the overtemperature of the pipe wall. Fault tree structure was used to uncover the multiplayer logic between the overtempera ture of the superheater's pipe wall and the faults.

  2. Deflection-based method for seismic response analysis of concrete walls: Benchmarking of CAMUS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Prabir C. [Civil and Structural Engineering Division, Atomic Energy Regulatory Board (India)]. E-mail: pcb@aerb.gov.in; Roshan, A.D. [Civil and Structural Engineering Division, Atomic Energy Regulatory Board (India)

    2007-07-15

    A number of shake table tests had been conducted on the scaled down model of a concrete wall as part of CAMUS experiment. The experiments were conducted between 1996 and 1998 in the CEA facilities in Saclay, France. Benchmarking of CAMUS experiments was undertaken as a part of the coordinated research program on 'Safety Significance of Near-Field Earthquakes' organised by International Atomic Energy Agency (IAEA). Technique of deflection-based method was adopted for benchmarking exercise. Non-linear static procedure of deflection-based method has two basic steps: pushover analysis, and determination of target displacement or performance point. Pushover analysis is an analytical procedure to assess the capacity to withstand seismic loading effect that a structural system can offer considering the redundancies and inelastic deformation. Outcome of a pushover analysis is the plot of force-displacement (base shear-top/roof displacement) curve of the structure. This is obtained by step-by-step non-linear static analysis of the structure with increasing value of load. The second step is to determine target displacement, which is also known as performance point. The target displacement is the likely maximum displacement of the structure due to a specified seismic input motion. Established procedures, FEMA-273 and ATC-40, are available to determine this maximum deflection. The responses of CAMUS test specimen are determined by deflection-based method and analytically calculated values compare well with the test results.

  3. Automatic Video-based Analysis of Human Motion

    DEFF Research Database (Denmark)

    Fihl, Preben

    received great interest from both industry and research communities. The focus of this thesis is on video-based analysis of human motion and the thesis presents work within three overall topics, namely foreground segmentation, action recognition, and human pose estimation. Foreground segmentation is often...... foreground camouflage, shadows, and moving backgrounds. The method continuously updates the background model to maintain high quality segmentation over long periods of time. Within action recognition the thesis presents work on both recognition of arm gestures and gait types. A key-frame based approach...... range of gait which deals with an inherent ambiguity of gait types. Human pose estimation does not target a specific action but is considered as a good basis for the recognition of any action. The pose estimation work presented in this thesis is mainly concerned with the problems of interacting people...

  4. Stochastic analysis of the motion of DNA nanomechanical bipeds.

    Science.gov (United States)

    Ben-Ari, Iddo; Boushaba, Khalid; Matzavinos, Anastasios; Roitershtein, Alexander

    2011-08-01

    In this paper, we formulate and analyze a Markov process modeling the motion of DNA nanomechanical walking devices.We consider a molecular biped restricted to a well-defined one-dimensional track and study its asymptotic behavior.Our analysis allows for the biped legs to be of different molecular composition, and thus to contribute differently to the dynamics. Our main result is a functional central limit theorem for the biped with an explicit formula for the effective diffusivity coefficient in terms of the parameters of the model. A law of large numbers, a recurrence/transience characterization and large deviations estimates are also obtained.Our approach is applicable to a variety of other biological motors such as myosin and motor proteins on polymer filaments.

  5. Autonomous rendezvous and proximate motion of satellites - A covariance analysis

    Science.gov (United States)

    Mackison, Donald L.; Morenthaler, George W.

    1992-08-01

    The construction of large (10 exp 6 kg) spacecraft in orbit will, in order to meet the requirements of interplanetary launch windows and restrictions of launch facilities require the launch of several 100,000-kg payloads using the Heavy Lift Launch Vehicle (HLLV), and their subsequent in-orbit assembly into a completed spacecraft. This assembly will require that the components rendezvous and dock within a reasonable time, taking into consideration launch window restrictions and the operating time limits on the component spacecraft. This will require that the rendezvous and docking operations be accomplished autonomously, without ground control. The trajectory and attitude control of a chase satellite to rendezvous with a target satellite are modeled using the Euler-Hill equations of relative orbital motion, and a linearized set of relative attitude parameters. The effect of uncertainties in the orbit dynamics and sensors, and the attitude dynamics and sensors are modeled using a linearized covariance analysis.

  6. Continuous motion decoding from EMG using independent component analysis and adaptive model training.

    Science.gov (United States)

    Zhang, Qin; Xiong, Caihua; Chen, Wenbin

    2014-01-01

    Surface Electromyography (EMG) is popularly used to decode human motion intention for robot movement control. Traditional motion decoding method uses pattern recognition to provide binary control command which can only move the robot as predefined limited patterns. In this work, we proposed a motion decoding method which can accurately estimate 3-dimensional (3-D) continuous upper limb motion only from multi-channel EMG signals. In order to prevent the muscle activities from motion artifacts and muscle crosstalk which especially obviously exist in upper limb motion, the independent component analysis (ICA) was applied to extract the independent source EMG signals. The motion data was also transferred from 4-manifold to 2-manifold by the principle component analysis (PCA). A hidden Markov model (HMM) was proposed to decode the motion from the EMG signals after the model trained by an adaptive model identification process. Experimental data were used to train the decoding model and validate the motion decoding performance. By comparing the decoded motion with the measured motion, it is found that the proposed motion decoding strategy was feasible to decode 3-D continuous motion from EMG signals.

  7. A review of vision-based motion analysis in sport.

    Science.gov (United States)

    Barris, Sian; Button, Chris

    2008-01-01

    Efforts at player motion tracking have traditionally involved a range of data collection techniques from live observation to post-event video analysis where player movement patterns are manually recorded and categorized to determine performance effectiveness. Due to the considerable time required to manually collect and analyse such data, research has tended to focus only on small numbers of players within predefined playing areas. Whilst notational analysis is a convenient, practical and typically inexpensive technique, the validity and reliability of the process can vary depending on a number of factors, including how many observers are used, their experience, and the quality of their viewing perspective. Undoubtedly the application of automated tracking technology to team sports has been hampered because of inadequate video and computational facilities available at sports venues. However, the complex nature of movement inherent to many physical activities also represents a significant hurdle to overcome. Athletes tend to exhibit quick and agile movements, with many unpredictable changes in direction and also frequent collisions with other players. Each of these characteristics of player behaviour violate the assumptions of smooth movement on which computer tracking algorithms are typically based. Systems such as TRAKUS, SoccerMan, TRAKPERFORMANCE, Pfinder and Prozone all provide extrinsic feedback information to coaches and athletes. However, commercial tracking systems still require a fair amount of operator intervention to process the data after capture and are often limited by the restricted capture environments that can be used and the necessity for individuals to wear tracking devices. Whilst some online tracking systems alleviate the requirements of manual tracking, to our knowledge a completely automated system suitable for sports performance is not yet commercially available. Automatic motion tracking has been used successfully in other domains outside

  8. Effectiveness of an Automatic Tracking Software in Underwater Motion Analysis

    Directory of Open Access Journals (Sweden)

    Fabrício A. Magalhaes

    2013-12-01

    Full Text Available Tracking of markers placed on anatomical landmarks is a common practice in sports science to perform the kinematic analysis that interests both athletes and coaches. Although different software programs have been developed to automatically track markers and/or features, none of them was specifically designed to analyze underwater motion. Hence, this study aimed to evaluate the effectiveness of a software developed for automatic tracking of underwater movements (DVP, based on the Kanade-Lucas-Tomasi feature tracker. Twenty-one video recordings of different aquatic exercises (n = 2940 markers’ positions were manually tracked to determine the markers’ center coordinates. Then, the videos were automatically tracked using DVP and a commercially available software (COM. Since tracking techniques may produce false targets, an operator was instructed to stop the automatic procedure and to correct the position of the cursor when the distance between the calculated marker’s coordinate and the reference one was higher than 4 pixels. The proportion of manual interventions required by the software was used as a measure of the degree of automation. Overall, manual interventions were 10.4% lower for DVP (7.4% than for COM (17.8%. Moreover, when examining the different exercise modes separately, the percentage of manual interventions was 5.6% to 29.3% lower for DVP than for COM. Similar results were observed when analyzing the type of marker rather than the type of exercise, with 9.9% less manual interventions for DVP than for COM. In conclusion, based on these results, the developed automatic tracking software presented can be used as a valid and useful tool for underwater motion analysis.

  9. A Feedback-Based Algorithm for Motion Analysis with Application to Object Tracking

    Directory of Open Access Journals (Sweden)

    P. S. Sastry

    2007-01-01

    Full Text Available We present a motion detection algorithm which detects direction of motion at sufficient number of points and thus segregates the edge image into clusters of coherently moving points. Unlike most algorithms for motion analysis, we do not estimate magnitude of velocity vectors or obtain dense motion maps. The motivation is that motion direction information at a number of points seems to be sufficient to evoke perception of motion and hence should be useful in many image processing tasks requiring motion analysis. The algorithm essentially updates the motion at previous time using the current image frame as input in a dynamic fashion. One of the novel features of the algorithm is the use of some feedback mechanism for evidence segregation. This kind of motion analysis can identify regions in the image that are moving together coherently, and such information could be sufficient for many applications that utilize motion such as segmentation, compression, and tracking. We present an algorithm for tracking objects using our motion information to demonstrate the potential of this motion detection algorithm.

  10. A Feedback-Based Algorithm for Motion Analysis with Application to Object Tracking

    Directory of Open Access Journals (Sweden)

    Shah Shesha

    2007-01-01

    Full Text Available We present a motion detection algorithm which detects direction of motion at sufficient number of points and thus segregates the edge image into clusters of coherently moving points. Unlike most algorithms for motion analysis, we do not estimate magnitude of velocity vectors or obtain dense motion maps. The motivation is that motion direction information at a number of points seems to be sufficient to evoke perception of motion and hence should be useful in many image processing tasks requiring motion analysis. The algorithm essentially updates the motion at previous time using the current image frame as input in a dynamic fashion. One of the novel features of the algorithm is the use of some feedback mechanism for evidence segregation. This kind of motion analysis can identify regions in the image that are moving together coherently, and such information could be sufficient for many applications that utilize motion such as segmentation, compression, and tracking. We present an algorithm for tracking objects using our motion information to demonstrate the potential of this motion detection algorithm.

  11. Untypical Undergraduate Research: Player Motion Analysis in Sports

    Science.gov (United States)

    Loerke, Dinah

    There is significant concern about the degree of attrition in STEM disciplines from the start of K-12 through to the end of higher education, and the analysis of the `leaky pipeline' from the various institutions has identified a critical decline - which may be as high as 60 percent - between the fraction of students who identify as having an interest in a science or engineering major at the start of college/university, and the fraction of students who ultimately graduate with a STEM degree. It has been shown that this decline is even more dramatic for women and underrepresented minorities (Blickenstaff 2005, Metcalf 2010). One intervention which has been proven to be effective for retention of potential STEM students is early research experience, particularly if it facilitates the students' integration into a STEM learning community (Graham et al. 2013, Toven-Lindsey et al. 2015). In other words, to retain students in STEM majors, we would like to encourage them to `think of themselves as scientists', and simultaneously promote supportive peer networks. The University of Denver (DU) already has a strong undergraduate research program. However, while the current program provides valuable training for many students, it likely comes too late to be effective for student retention in STEM, because it primarily serves older students who have already finished the basic coursework in their discipline; within physics, we know that the introductory physics courses already serve as gatekeeper courses that cause many gifted but `non-typical' students to lose interest in pursuing a STEM major (Tobias 1990). To address this issue, my lab is developing a small research spinoff program in which we apply spatiotemporal motion analysis to the motion trajectories of players in sports, using video recordings of DU Pioneer hockey games. This project aims to fulfill a dual purpose: The research is framed in a way that we think is attractive and accessible for beginning students who

  12. Rough-Wall Channel Analysis Using Suboptimal Control Theory

    Science.gov (United States)

    Flores, O.; Jimenez, J.; Tenpleton, J.

    2003-01-01

    The original aim of this work was to shed some light on the physics of turbulence over rough walls using large-eddy simulations and the suboptimal-control wall boundary conditions introduced by Nicoud et al. It was hoped that, if that algorithm was used to fit the mean velocity profile of the simulations to that of a rough-walled channel, instead of to a smooth one, the wall stresses introduced by the control algorithm would give some indication of what aspects of rough walls are most responsible for the modification of the flow in real turbulence. It was similarly expected that the structure of the resulting velocity fluctuations would share some of the characteristics of rough-walled flows, thus again suggesting what is intrinsic and what is accidental in the effect of geometric wall roughness. A secondary goal was to study the effect of 'unphysical' boundary conditions on the outside flow by observing how a relatively major change of the target velocity profile, and therefore presumably of the applied wall stresses, modifies properties such as the dominant length scales of the velocity fluctuations away from the wall. As will be seen below, this secondary goal grew more important during the course of the study, which was carried out during a short summer visit of the first two authors to the CTR. It became clear that there are open questions about the way in which the control algorithm models the boundary conditions, even for smooth walls, and that these questions make the physical interpretation of the results difficult. Considerable more work in that area seems to be needed before even relatively advanced large-eddy simulations, such as these, can be used to draw conclusions about the physics of wall-bounded turbulent flows. The numerical method is the same as in Nicoud et al. The modifications introduced in the original code are briefly described in section 2, but the original paper should be consulted for a full description of the algorithm. The results are

  13. Manipulation of multiple 360o domain wall structures and its current-driven motion in a magnetic nanostripe

    Directory of Open Access Journals (Sweden)

    Wenjun Dong

    2015-11-01

    Full Text Available Dynamics of multiple transverse walls (TWs in a magnetic nanostripe is studied by micromagnetic simulations. It shows that, when TWs are arranged in a stripe with same orientation, they will attract each other and finally annihilate. However, when adjacent TWs are arranged with opposite orientation, a metastable complex wall can be formed, e.g., two TWs lead to 360o wall. For three or more TWs, the formed complex wall includes a number of 360o substructures, which is called multiple 360o structure (M360S here. The M360S itself may be used to store multiple logical data since each 360o substructure can act as logical ”0” or ”1”. On the other hand, the M360S may behave like single TW under an applied current, namely, the M360S can be driven steadily by current like that of single TW. A parity effect of the number of 360o substructures on the critical current for the annihilation is found. Namely, when the number is odd or even, the critical current increase or decrease with the increasing of the number, respectively. The parity effect is relevant to the out-of-plane magnetic moment of the M360S.

  14. An analysis of human motion detection systems use during elder exercise routines.

    Science.gov (United States)

    Alexander, Gregory L; Havens, Timothy C; Rantz, Marilyn; Keller, James; Casanova Abbott, Carmen

    2010-03-01

    Human motion analysis provides motion pattern and body pose estimations. This study integrates computer-vision techniques and explores a markerless human motion analysis system. Using human-computer interaction (HCI) methods and goals, researchers use a computer interface to provide feedback about range of motion to users. A total of 35 adults aged 65 and older perform three exercises in a public gym while human motion capture methods are used. Following exercises, participants are shown processed human motion images captured during exercises on a customized interface. Standardized questionnaires are used to elicit responses from users during interactions with the interface. A matrix of HCI goals (effectiveness, efficiency, and user satisfaction) and emerging themes are used to describe interactions. Sixteen users state the interface would be useful, but not necessarily for safety purposes. Users want better image quality, when expectations are matched satisfaction increases, and unclear meaning of motion measures decreases satisfaction.

  15. Sampling-based Motion Planning: Analysis and Path Quality

    NARCIS (Netherlands)

    Geraerts, R.J.

    2006-01-01

    One of the fundamental tasks robots have to perform is planning their motions while avoiding collisions with obstacles in the environment. This is the central topic of the thesis. We restrict ourselves to motion planning for two- and three-dimensional rigid bodies and articulated robots moving in st

  16. Design and analysis of a rotary motion controller

    Directory of Open Access Journals (Sweden)

    Julio Cesar Caye

    2015-12-01

    Full Text Available This paper presents the design of a rotary motion controller based on the peritrochoid geometry of the rotary (Wankle engine. It uses an orifice limited flow of incompressible fluid between the chambers of the Wankle-type geometry to control the rotation of the rotor. The paper develops the theory of operation and then implements the design as a Matlab model to simulate the motion control under various conditions. It is found that the time to reach stabilised motion is determined by the orifice size and fluid density. When stabilised motion is achieved, the motion dependence on material and geometry factors is determined by the orifice flow equation. The angular velocity is also found to have a square root dependence on the applied torque when in the stabilised regime.

  17. Motion as perturbation. II. Development of the method for dosimetric analysis of motion effects with fixed-gantry IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Nelms, Benjamin E. [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Opp, Daniel; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir, E-mail: vladimir.feygelman@moffitt.org [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States)

    2014-06-15

    was 5 s, with the resulting average motion speed of 1.45 cm/s. The motion-perturbed high resolution (2 mm voxel) volumetric dose grids on the MC2 phantom were generated for each beam. From each grid, a coronal dose plane at the detector level was extracted and compared to the corresponding moving MC2 measurement, using gamma analysis with both global (G) and local (L) dose-error normalization. Results: Using the TG-119 criteria of (3%G/3 mm), per beam average gamma analysis passing rates exceeded 95% in all cases. No individual beam had a passing rate below 91%. LDVE correction eliminated systematic disagreement patterns at the beams’ aperture edges. In a representative example, application of LDVE correction improved (2%L/2 mm) gamma analysis passing rate for an IMRT beam from 74% to 98%. Conclusions: The effect of motion on the moving region-of-interest IMRT dose can be estimated with a standard, static phantom QA measurement, provided the motion characteristics are independently known from 4D CT or otherwise. The motion-perturbed absolute dose estimates were validated by the direct planar diode array measurements, and were found to reliably agree with them in a homogeneous phantom.

  18. On selection and scaling of ground motions for analysis of seismically isolated structures

    Science.gov (United States)

    Pant, Deepak R.; Maharjan, Manika

    2016-12-01

    A broader consensus on the number of ground motions to be used and the method of scaling to be adopted for nonlinear response history analysis (RHA) of structures is yet to be reached. Therefore, in this study, the effects of selection and scaling of ground motions on the response of seismically isolated structures, which are routinely designed using nonlinear RHA, are investigated. For this purpose, isolation systems with a range of properties subjected to bidirectional excitation are considered. Benchmark response of the isolation systems is established using large sets of unscaled ground motions systematically categorized into pulse-like, non-pulse-like, and mixed set of motions. Different subsets of seven to 14 ground motions are selected from these large sets using (a) random selection and (b) selection based on the best match of the shape of the response spectrum of ground motions to the target spectrum. Consequences of weighted scaling (also commonly referred to as amplitude scaling or linear scaling) as well as spectral matching are investigated. The ground motion selection and scaling procedures are evaluated from the viewpoint of their accuracy, efficiency, and consistency in predicting the benchmark response. It is confirmed that seven time histories are sufficient for a reliable prediction of isolation system displacement demands, for all ground motion subsets, selection and scaling procedures, and isolation systems considered. If ground motions are selected based on their best match to the shape of the target response spectrum (which should be preferred over randomly selected motions), weighted scaling should be used if pulse-like motions are considered, either of weighted scaling or spectral matching can be used if non-pulse-like motions are considered, and an average of responses from weighted-scaled and spectrum-matched ground motions should be used for a mixed set of motions. On the other hand, the importance of randomly selected motions in

  19. Analysis of domain wall dynamics based on skewness of magnetic Barkhausen noise for applied stress determination

    Science.gov (United States)

    Ding, Song; Tian, GuiYun; Dobmann, Gerd; Wang, Ping

    2017-01-01

    Skewness of Magnetic Barkhausen Noise (MBN) signal is used as a new feature for applied stress determination. After experimental studies, skewness presents its ability for measuring applied tensile stress compared with conventional feature, meanwhile, a non-linear behavior of this new feature and an independence of the excitation conditions under compressive stress are found and discussed. Effective damping during domain wall motion influencing the asymmetric shape of the MBN statistical distribution function is discussed under compressive and tensile stress variation. Domain wall (DW) energy and distance between pinning edges of the DW are considered altering the characteristic relaxation time, which is the reason for the non-linear phenomenon of skewness.

  20. Theoretical Analysis of Noise of Piston Knocking Cylinder Wall in Automotive Engines

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the loading conditions of engine, applying difference method to solve the hydrodynamic lubrication equation of piston skirt movement, the force acting on piston skirt and the moment on wrist pin were obtained. A computer program for simulating the piston second order motion was conducted to calculate the lateral motion of the upper part and the bottom part of piston skirts of the engine of automotive model CA1091. From the simulated result, the maximal impacting phase and the maximal impacting region of the piston were obtained. The result can be used for designing engine, diagnosing the noise of piston knocking cylinder wall and explaining many practical fault phenomena in theory.

  1. Characterizing Detrended Fluctuation Analysis of multifractional Brownian motion

    Science.gov (United States)

    Setty, V. A.; Sharma, A. S.

    2015-02-01

    The Hurst exponent (H) is widely used to quantify long range dependence in time series data and is estimated using several well known techniques. Recognizing its ability to remove trends the Detrended Fluctuation Analysis (DFA) is used extensively to estimate a Hurst exponent in non-stationary data. Multifractional Brownian motion (mBm) broadly encompasses a set of models of non-stationary data exhibiting time varying Hurst exponents, H(t) as against a constant H. Recently, there has been a growing interest in time dependence of H(t) and sliding window techniques have been used to estimate a local time average of the exponent. This brought to fore the ability of DFA to estimate scaling exponents in systems with time varying H(t) , such as mBm. This paper characterizes the performance of DFA on mBm data with linearly varying H(t) and further test the robustness of estimated time average with respect to data and technique related parameters. Our results serve as a bench-mark for using DFA as a sliding window estimator to obtain H(t) from time series data.

  2. Real-time ultrasound-tagging to track the 2D motion of the common carotid artery wall in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Zahnd, Guillaume, E-mail: g.zahnd@erasmusmc.nl [Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus MC, Rotterdam 3000 CA (Netherlands); Salles, Sébastien; Liebgott, Hervé; Vray, Didier [Université de Lyon, CREATIS, CNRS UMR 5220, INSERM U1044, INSA-Lyon, Université Lyon 1, Lyon 69100 (France); Sérusclat, André [Department of Radiology, Louis Pradel Hospital, Lyon 69500 (France); Moulin, Philippe [Department of Endocrinology, Louis Pradel Hospital, Hospices Civils de Lyon, Université Lyon 1, Lyon 69100, France and INSERM UMR 1060, Lyon 69500 (France)

    2015-02-15

    Purpose: Tracking the motion of biological tissues represents an important issue in the field of medical ultrasound imaging. However, the longitudinal component of the motion (i.e., perpendicular to the beam axis) remains more challenging to extract due to the rather coarse resolution cell of ultrasound scanners along this direction. The aim of this study is to introduce a real-time beamforming strategy dedicated to acquire tagged images featuring a distinct pattern in the objective to ease the tracking. Methods: Under the conditions of the Fraunhofer approximation, a specific apodization function was applied to the received raw channel data, in real-time during image acquisition, in order to introduce a periodic oscillations pattern along the longitudinal direction of the radio frequency signal. Analytic signals were then extracted from the tagged images, and subpixel motion tracking of the intima–media complex was subsequently performed offline, by means of a previously introduced bidimensional analytic phase-based estimator. Results: The authors’ framework was applied in vivo on the common carotid artery from 20 young healthy volunteers and 6 elderly patients with high atherosclerosis risk. Cine-loops of tagged images were acquired during three cardiac cycles. Evaluated against reference trajectories manually generated by three experienced analysts, the mean absolute tracking error was 98 ± 84 μm and 55 ± 44 μm in the longitudinal and axial directions, respectively. These errors corresponded to 28% ± 23% and 13% ± 9% of the longitudinal and axial amplitude of the assessed motion, respectively. Conclusions: The proposed framework enables tagged ultrasound images of in vivo tissues to be acquired in real-time. Such unconventional beamforming strategy contributes to improve tracking accuracy and could potentially benefit to the interpretation and diagnosis of biomedical images.

  3. Motion/imagery secure cloud enterprise architecture analysis

    Science.gov (United States)

    DeLay, John L.

    2012-06-01

    Cloud computing with storage virtualization and new service-oriented architectures brings a new perspective to the aspect of a distributed motion imagery and persistent surveillance enterprise. Our existing research is focused mainly on content management, distributed analytics, WAN distributed cloud networking performance issues of cloud based technologies. The potential of leveraging cloud based technologies for hosting motion imagery, imagery and analytics workflows for DOD and security applications is relatively unexplored. This paper will examine technologies for managing, storing, processing and disseminating motion imagery and imagery within a distributed network environment. Finally, we propose areas for future research in the area of distributed cloud content management enterprises.

  4. Sensitivity analysis of the GNSS derived Victoria plate motion

    Science.gov (United States)

    Apolinário, João; Fernandes, Rui; Bos, Machiel

    2014-05-01

    estimated trend (Williams 2003, Langbein 2012). Finally, our preferable angular velocity estimation is used to evaluate the consequences on the kinematics of the Victoria block, namely the magnitude and azimuth of the relative motions with respect to the Nubia and Somalia plates and their tectonic implications. References Agnew, D. C. (2013). Realistic simulations of geodetic network data: The Fakenet package, Seismol. Res. Lett., 84 , 426-432, doi:10.1785/0220120185. Blewitt, G. & Lavallee, D., (2002). Effect of annual signals on geodetic velocity, J. geophys. Res., 107(B7), doi:10.1029/2001JB000570. Bos, M.S., R.M.S. Fernandes, S. Williams, L. Bastos (2012) Fast Error Analysis of Continuous GNSS Observations with Missing Data, Journal of Geodesy, doi: 10.1007/s00190-012-0605-0. Bos, M.S., L. Bastos, R.M.S. Fernandes, (2009). The influence of seasonal signals on the estimation of the tectonic motion in short continuous GPS time-series, J. of Geodynamics, j.jog.2009.10.005. Fernandes, R.M.S., J. M. Miranda, D. Delvaux, D. S. Stamps and E. Saria (2013). Re-evaluation of the kinematics of Victoria Block using continuous GNSS data, Geophysical Journal International, doi:10.1093/gji/ggs071. Langbein, J. (2012). Estimating rate uncertainty with maximum likelihood: differences between power-law and flicker-random-walk models, Journal of Geodesy, Volume 86, Issue 9, pp 775-783, Williams, S. D. P. (2003). Offsets in Global Positioning System time series, J. Geophys. Res., 108, 2310, doi:10.1029/2002JB002156, B6.

  5. Cell wall proteome analysis of Arabidopsis thaliana mature stems.

    Science.gov (United States)

    Duruflé, Harold; Clemente, Hélène San; Balliau, Thierry; Zivy, Michel; Dunand, Christophe; Jamet, Elisabeth

    2017-04-01

    Plant stems carry flowers necessary for species propagation and need to be adapted to mechanical disturbance and environmental factors. The stem cell walls are different from other organs and can modify their rigidity or viscoelastic properties for the integrity and the robustness required to withstand mechanical impacts and environmental stresses. Plant cell wall is composed of complex polysaccharide networks also containing cell wall proteins (CWPs) crucial to perceive and limit the environmental effects. The CWPs are fundamental players in cell wall remodeling processes, and today, only 86 have been identified from the mature stems of the model plant Arabidopsis thaliana. With a destructive method, this study has enlarged its coverage to 302 CWPs. This new proteome is mainly composed of 27.5% proteins acting on polysaccharides, 16% proteases, 11.6% oxido-reductases, 11% possibly related to lipid metabolism and 11% of proteins with interacting domains with proteins or polysaccharides. Compared to stem cell wall proteomes already available (Brachypodium distachyon, Sacharum officinarum, Linum usitatissimum, Medicago sativa), that of A. thaliana stems has a higher proportion of proteins acting on polysaccharides and of proteases, but a lower proportion of oxido-reductases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Experimental Thermal Analysis of Diesel Engine Piston and Cylinder Wall

    Directory of Open Access Journals (Sweden)

    Subodh Kumar Sharma

    2015-01-01

    Full Text Available Knowledge of piston and cylinder wall temperature is necessary to estimate the thermal stresses at different points; this gives an idea to the designer to take care of weaker cross section area. Along with that, this temperature also allows the calculation of heat losses through piston and cylinder wall. The proposed methodology has been successfully applied to a water-cooled four-stroke direct-injection diesel engine and it allows the estimation of the piston and cylinder wall temperature. The methodology described here combines numerical simulations based on FEM models and experimental procedures based on the use of thermocouples. Purposes of this investigation are to measure the distortion in the piston, temperature, and radial thermal stresses after thermal loading. To check the validity of the heat transfer model, measure the temperature through direct measurement using thermocouple wire at several points on the piston and cylinder wall. In order to prevent thermocouple wire entanglement, a suitable pathway was designed. Appropriate averaged thermal boundary conditions such as heat transfer coefficients were set on different surfaces for FE model. The study includes the effects of the thermal conductivity of the material of piston, piston rings, and combustion chamber wall. Results show variation of temperature, stresses, and deformation at various points on the piston.

  7. Circular motion analysis of time-varying bioimpedance.

    Science.gov (United States)

    Sanchez, B; Louarroudi, E; Rutkove, S B; Pintelon, R

    2015-11-01

    This paper presents a step forward towards the analysis of a linear periodically time-varying (PTV) bioimpedance ZPTV(jw, t), which is an important subclass of a linear time-varying (LTV) bioimpedance. Similarly to the Fourier coefficients of a periodic signal, a PTV impedance can be decomposed into frequency dependent impedance phasors, [Formula: see text], that are rotating with an angular speed of wr = 2πr/TZ. The vector length of these impedance phasors corresponds to the amplitude of the rth-order harmonic impedance |Zr( jw)| and the initial phase is given by Φr(w, t0) = [Symbol: see text]Zr( jw) + 2πrt0/TZ, with t0∈[0, T] being a time instant within the measurement time T. The impedance period TZ stands for the cycle length of the bio-system under investigation; for example, the elapsed time between two consecutive R-waves in the electrocardiogram or the breathing periodicity in case of the heart or lungs, respectively. First, it is demonstrated that the harmonic impedance phasor [Formula: see text], at a particular measured frequency k, can be represented by a rotating phasor, leading to the so-called circular motion analysis technique. Next, the two dimensional (2D) representation of the harmonic impedance phasors is then extended to a three-dimensional (3D) coordinate system by taking into account the frequency dependence. Finally, we introduce a new visualizing tool to summarize the frequency response behavior of ZPTV( jw, t) into a single 3D plot using the local Frenet-Serret frame. This novel 3D impedance representation is then compared with the 3D Nyquist representation of a PTV impedance. The concepts are illustrated through real measurements conducted on a PTV RC-circuit.

  8. A Study of Motion Sickness: Mathematical Modeling and Data Analysis

    Science.gov (United States)

    1988-12-01

    levels of motion sick- ness experienced by a test subject during the course of an experiment (21:97; 25:59; 27:84). In 1987, Drylie, Fix, and Gaudreault ...pro- cedures. Drylie and Gaudreault reported additional conclusions concerning motion sickness trends (11; 17). Fix developed a new equation for...and Gaudreault also noted low frequency EEG signals in the 0.1 Hz range (17:28). However, only one of their subjects had EEG signals with an amplitude

  9. Analysis of stable resistive wall modes in a rotating plasma

    Science.gov (United States)

    Garofalo, A. M.; Jensen, T. H.; Strait, E. J.

    2003-12-01

    Measurements of the resistive wall mode (RWM) response to external resonant field pulses yield complete knowledge of the mode characteristics in the parameter range explored. An ideal magnetohydrodynamics model [Garofalo et al., Phys. Plasmas 9, 4573 (2002)] has been generalized to include the effects of plasma rotation and dissipation, and the new model is found to explain quantitatively the experimental observations. Rotation of the RWM with respect to the wall is often described as an essential feature of the mechanism by which plasma rotation stabilizes the RWM. This interpretation of the rotational stabilization of the RWM appears inconsistent with the measurements from recent DIII-D [Luxon and Davis, Fusion Technol. 8, 441 (1985)] experiments. It is found that the theoretically predicted mode rotation with respect to the wall is not needed for stabilization and is only a consequence of torque balance in the absence of magnetic-field nonaxisymmetries.

  10. Vision Servo Motion Control and Error Analysis of a Coplanar XXY Stage for Image Alignment Motion

    Directory of Open Access Journals (Sweden)

    Hau-Wei Lee

    2013-01-01

    Full Text Available In recent years, as there is demand for smart mobile phones with touch panels, the alignment/compensation system of alignment stage with vision servo control has also increased. Due to the fact that the traditional stacked-type XYθ stage has cumulative errors of assembly and it is heavy, it has been gradually replaced by the coplanar stage characterized by three actuators on the same plane with three degrees of freedom. The simplest image alignment mode uses two cameras as the equipments for feedback control, and the work piece is placed on the working stage. The work piece is usually engraved/marked. After the cameras capture images and when the position of the mark in the camera is obtained by image processing, the mark can be moved to the designated position in the camera by moving the stage and using alignment algorithm. This study used a coplanar XXY stage with 1 μm positioning resolution. Due to the fact that the resolution of the camera is about 3.75 μm per pixel, thus a subpixel technology is used, and the linear and angular alignment repeatability of the alignment system can achieve 1 μm and 5 arcsec, respectively. The visual servo motion control for alignment motion is completed within 1 second using the coplanar XXY stage.

  11. Segmentation, statistical analysis, and modelling of the wall system in ceramic foams

    Energy Technology Data Exchange (ETDEWEB)

    Kampf, Jürgen, E-mail: juergen.kampf@uni-ulm.de [University of Ulm, Mathematics Department, 89069 Ulm (Germany); Schlachter, Anna-Lena [University of Kaiserslautern, Mathematics Department, 67653 Kaiserslautern (Germany); Redenbach, Claudia, E-mail: redenbach@mathematik.uni-kl.de [University of Kaiserslautern, Mathematics Department, 67653 Kaiserslautern (Germany); Liebscher, André, E-mail: liebscher@mathematik.uni-kl.de [University of Kaiserslautern, Mathematics Department, 67653 Kaiserslautern (Germany)

    2015-01-15

    Closed walls in otherwise open foam structures may have a great impact on macroscopic properties of the materials. In this paper, we present two algorithms for the segmentation of such closed walls from micro-computed tomography images of the foam structure. The techniques are compared on simulated data and applied to tomographic images of ceramic filters. This allows for a detailed statistical analysis of the normal directions and sizes of the walls. Finally, we explain how the information derived from the segmented wall system can be included in a stochastic microstructure model for the foam.

  12. Upper bound seismic rotational stability analysis of gravity retaining walls considering embedment depth

    Institute of Scientific and Technical Information of China (English)

    刘杰; 黄达; 杨超; 孙莎

    2015-01-01

    Stability analysis of gravity retaining wall was currently based on the assumption that the wall had no embedment depth. The effect of earth berm was usually neglected. The present work highlighted the importance of embedment depth when assessing the seismic stability of gravity retaining walls with the pattern of pure rotation. In the framework of upper bound theorem of limit analysis, pseudo-static method was applied into two groups of parallel rigid soil slices methods in order to account for the effect of embedment depth on evaluating the critical acceleration of wall-soil system. The present analytical solution is identical to the results obtained from using limit equilibrium method, and the two methods are based on different theory backgrounds. Parameter analysis indicates that the critical acceleration increases slowly when the ratio of the embedment depth to the total height of the wall is from 0 to 0.15 and increases drastically when the ratio exceeds 0.15.

  13. A Mobile Motion Analysis System Using Intertial Sensors for Analysis of Lower Limb Prosthetics

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, John Kyle P [ORNL; Ericson, Milton Nance [ORNL; Farquhar, Ethan [ORNL; Lind, Randall F [ORNL; Evans III, Boyd Mccutchen [ORNL

    2011-01-01

    Soldiers returning from the global war on terror requiring lower leg prosthetics generally have different concerns and requirements than the typical lower leg amputee. These subjects are usually young, wish to remain active and often desire to return to active military duty. As such, they demand higher performance from their prosthetics, but are at risk for chronic injury and joint conditions in their unaffected limb. Motion analysis is a valuable tool in assessing the performance of new and existing prosthetic technologies as well as the methods in fitting these devices to both maximize performance and minimize risk of injury for the individual soldier. We are developing a mobile, low-cost motion analysis system using inertial measurement units (IMUs) and two custom force sensors that detect ground reaction forces and moments on both the unaffected limb and prosthesis. IMUs were tested on a robot programmed to simulate human gait motion. An algorithm which uses a kinematic model of the robot and an extended Kalman filter (EKF) was used to convert the rates and accelerations from the gyro and accelerometer into joint angles. Compared to encoder data from the robot, which was considered the ground truth in this experiment, the inertial measurement system had a RMSE of <1.0 degree. Collecting kinematic and kinetic data without the restrictions and expense of a motion analysis lab could help researchers, designers and prosthetists advance prosthesis technology and customize devices for individuals. Ultimately, these improvements will result in better prosthetic performance for the military population.

  14. Tectonic Motion of Malaysia: Analysis from Years 2001 TO 2013

    Science.gov (United States)

    Gill, J.; Shariff, N. S.; Omar, K.; Amin, Z. M.

    2015-10-01

    This paper seeks to investigate the tectonic motion of Malaysia using the Malaysian Active GPS Station (MASS) and Malaysia Realtime Kinematic GNSS Network (MyRTKnet) data from years 2001 to 2013. GNSS data were processed using Bernese 5.0, and plotted as a time series; whereby the period before and after the 2004 Sumatra-Andaman mega earthquake are plotted separately. From the time series, episodic events and stable inter-seismic deformation period are analysed. The results indicate that the 2001- 2004 and 2008-2011 periods were free from episodic events; hence, chosen to depict the tectonic motion of Malaysia before and after 2004 Sumatra-Andaman earthquake, respectively. The motion had a major change in direction and rate, especially for East Malaysia and South Peninsular Malaysia. This indicates there exist a long-term post-seismic deformation due to the 2004 mega earthquake. Nonetheless, the 2008-2011 inter-seismic period is stable, and suitable to represent the current long-term tectonic motion of Malaysia: Peninsular and East Malaysia moves south-east, at an average velocity of 0.89 ±0.01 cm/yr south and 1.70 ±0.02 cm/yr east, and 1.06 ±0.01 cm/yr south and 2.50 ±0.02 cm/yr east, respectively. In addition, the co-seismic motion for the 2005 Nias, 2007 Bengkulu and 2012 Northern Sumatra earthquakes after the 2004 Sumatra-Andaman earthquake are relatively small, indicating these three earthquakes have no significant contribution to the long-term tectonic motion of Malaysia. Overall, this paper aims to provide a general insight into the tectonic motion of Malaysia which, expectedly, may benefit other scientific fields.

  15. Prototype of a rectal wall ultrasound image analysis system

    Science.gov (United States)

    Xiao, Di; Ng, Wan S.; Abeyratne, Udantha R.; Tsang, Charles B.

    2002-05-01

    This paper presents a software system prototype for rectal wall ultrasound image processing, image display and 3D reconstruction and visualization of the rectal wall structure, which is aimed to help surgeons cope with large quantities of rectal wall ultrasound images. On the core image processing algorithm part, a novel multigradient field active contour model proposed by authors is used to complete the multi-layer boundary detection of the rectal wall. A novel unifying active contour model, which combines region information, gradient information and contour's internal constraint, is developed for tumor boundary detection. The region statistical information is described accurately by Gaussian Mixture Model, whose parameter solution is computed by Expectation-Maximization algorithm. The whole system is set up on Java platform. Java JAI technology is used for 2D image display, Java3D technology is employed for 3D reconstruction and visualization. The system prototype is currently composed of three main modules: image processing, image display and 3D visualization.

  16. Time-motion analysis of elite male kickboxing competition.

    Science.gov (United States)

    Ouergui, Ibrahim; Hssin, Nizar; Haddad, Monoem; Franchini, Emerson; Behm, David G; Wong, Del P; Gmada, Nabil; Bouhlel, Ezzedine

    2014-12-01

    The objective of the study was to analyze the time structure of high-level kickboxing matches. A total of 45 combats from 2 male World Championships were monitored using a time-motion analysis system. The combat time structure (i.e., high-intensity activity [HIA], low-intensity activity [LIA], and referee breaks or pauses) during competition and weight divisions was determined and compared. Results indicated that the time structures were HIA: 2.2 ± 1.2 seconds; LIA: 2.3 ± 0.8 seconds; pauses: 5.4 ± 4.3 seconds; and 3.4 ± 1.2 seconds between 2 subsequent HIA. The fighting to nonfighting ratio was found to be 1:1. Moreover, the number of HIA and LIA and the time of LIA decreased in latter rounds (e.g., the average number of HIA was 27.1 ± 7.1, 25.1 ± 6.6, and 24.9 ± 6.1, respectively, for rounds 1, 2, and 3), meanwhile the time and number of pauses increased (e.g., the average pause times were 12.8 ± 11.4, 22.3 ± 22.6, and 24.6 ± 23.3 seconds, respectively, for rounds 1, 2, and 3). The activity times did not differ among weight categories. The present results confirm the intermittent nature of kickboxing competition and provide coaches with more information on how to structure training sessions to mimic the physical demands in competition.

  17. Analysis of glacial and periglacial processes using structure from motion

    Science.gov (United States)

    Piermattei, L.; Carturan, L.; de Blasi, F.; Tarolli, P.; Dalla Fontana, G.; Vettore, A.; Pfeifer, N.

    2015-11-01

    Close-range photo-based surface reconstruction from the ground is rapidly emerging as an alternative to lidar (light detection and ranging), which today represents the main survey technique in many fields of geoscience. The recent evolution of photogrammetry, incorporating computer vision algorithms such as Structure from Motion (SfM) and dense image matching such as Multi-View Stereo (MVS), allows the reconstruction of dense 3-D point clouds for the photographed object from a sequence of overlapping images taken with a digital consumer camera. The objective of our work was to test the accuracy of the ground-based SfM-MVS approach in calculating the geodetic mass balance of a 2.1 km2 glacier in the Ortles-Cevedale Group, Eastern Italian Alps. In addition, we investigated the feasibility of using the image-based approach for the detection of the surface displacement rate of a neighbouring active rock glacier. Airborne laser scanning (ALS) data were used as benchmarks to estimate the accuracy of the photogrammetric DTMs and the reliability of the method in this specific application. The glacial and periglacial analyses were performed using both range and image-based surveying techniques, and the results were then compared. The results were encouraging because the SfM-MVS approach enables the reconstruction of high-quality DTMs which provided estimates of glacial and periglacial processes similar to those achievable by ALS. Different resolutions and accuracies were obtained for the glacier and the rock glacier, given the different survey geometries, surface characteristics and areal extents. The analysis of the SfM-MVS DTM quality allowed us to highlight the limitations of the adopted expeditious method in the studied alpine terrain and the potential of this method in the multitemporal study of glacial and periglacial areas.

  18. Finite Element Modeling and Analysis of Nonlinear Impact and Frictional Motion Responses Including Fluid—Structure Coupling Effects

    Directory of Open Access Journals (Sweden)

    Yong Zhao

    1997-01-01

    Full Text Available A nonlinear three dimensional (3D single rack model and a nonlinear 3D whole pool multi-rack model are developed for the spent fuel storage racks of a nuclear power plant (NPP to determine impacts and frictional motion responses when subjected to 3D excitations from the supporting building floor. The submerged free standing rack system and surrounding water are coupled due to hydrodynamic fluid-structure interaction (FSI using potential theory. The models developed have features that allow consideration of geometric and material nonlinearities including (1 the impacts of fuel assemblies to rack cells, a rack to adjacent racks or pool walls, and rack support legs to the pool floor; (2 the hydrodynamic coupling of fuel assemblies with their storing racks, and of a rack with adjacent racks, pool walls, and the pool floor; and (3 the dynamic motion behavior of rocking, twisting, and frictional sliding of rack modules. Using these models 3D nonlinear time history dynamic analyses are performed per the U.S. Nuclear Regulatory Commission (USNRC criteria. Since few such modeling, analyses, and results using both the 3D single and whole pool multiple rack models are available in the literature, this paper emphasizes description of modeling and analysis techniques using the SOLVIA general purpose nonlinear finite element code. Typical response results with different Coulomb friction coefficients are presented and discussed.

  19. Inertial motion capture system for biomechanical analysis in pressure suits

    Science.gov (United States)

    Di Capua, Massimiliano

    A non-invasive system has been developed at the University of Maryland Space System Laboratory with the goal of providing a new capability for quantifying the motion of the human inside a space suit. Based on an array of six microprocessors and eighteen microelectromechanical (MEMS) inertial measurement units (IMUs), the Body Pose Measurement System (BPMS) allows the monitoring of the kinematics of the suit occupant in an unobtrusive, self-contained, lightweight and compact fashion, without requiring any external equipment such as those necessary with modern optical motion capture systems. BPMS measures and stores the accelerations, angular rates and magnetic fields acting upon each IMU, which are mounted on the head, torso, and each segment of each limb. In order to convert the raw data into a more useful form, such as a set of body segment angles quantifying pose and motion, a series of geometrical models and a non-linear complimentary filter were implemented. The first portion of this works focuses on assessing system performance, which was measured by comparing the BPMS filtered data against rigid body angles measured through an external VICON optical motion capture system. This type of system is the industry standard, and is used here for independent measurement of body pose angles. By comparing the two sets of data, performance metrics such as BPMS system operational conditions, accuracy, and drift were evaluated and correlated against VICON data. After the system and models were verified and their capabilities and limitations assessed, a series of pressure suit evaluations were conducted. Three different pressure suits were used to identify the relationship between usable range of motion and internal suit pressure. In addition to addressing range of motion, a series of exploration tasks were also performed, recorded, and analysed in order to identify different motion patterns and trajectories as suit pressure is increased and overall suit mobility is reduced

  20. Motion Analysis of Thumb in Cellular Phone Use

    Directory of Open Access Journals (Sweden)

    Naotaka Sakai

    2010-01-01

    Full Text Available The thumb motion of 10 normal subjects during cellular phone use was measured using a reflective marker detection system to compare the maximum, minimum and range of flexion angles of the interphalangeal (IP, metacarpophalangeal (MP and carpometacarpal (CM joints. Two micro-reflective markers 3 mm in diameter were each placed on the dorsal surface of the distal phalanx, basal phalanx and metacarpal bone of the thumb. Three markers were placed on the dorsal hand in order to define the dorsal hand plane. Each subject pushed the 12 keys of a folding cellular phone with an 85-mm-long and 40-mm-wide keypad, sequentially from ‘1’ to ‘#’, and the pushing motion was recorded by six infrared video cameras for 12 seconds, using the VICON 612 system. The mean maximum flexion angle of the MP joint was significantly (p < .05 larger than the CM joint, and the mean minimum flexion angle of the CM joint was significantly (p < .01 smaller than the IP and MP joints. The mean range of motion of the IP joint was significantly (p < .05 larger than the MP and the CM joints. In a comparison of different key-pushing motions, only the CM joint was significantly (p < .05 larger in its range of motion. In conclusion, thumb motion on pushing the keys of the cellular phone was produced mainly by the MP and the CM joints. In addition, the ability to reach keys in different areas of the cellular phone keypad is regulated by changing the flexion angle of the CM joint.

  1. Integrated Life Cycle Energy and Greenhouse Gas Analysis of Exterior Wall Systems for Residential Buildings

    Directory of Open Access Journals (Sweden)

    Reza Broun

    2014-11-01

    Full Text Available This paper investigates the breakdown of primary energy use and greenhouse gas (GHG emissions of two common types of exterior walls in the U.K.: insulated concrete form (ICF and cavity walls. A comprehensive assessment was conducted to evaluate the environmental performance of each exterior wall system over 50 years of service life in Edinburgh and Bristol. The results indicate that for both wall systems, use phase is the major contributor to the overall environmental impacts, mainly due to associated electricity consumption. For the ICF wall system in Edinburgh, 91% of GHG emissions were attributed to the use phase, with 7.8% in the pre-use and 1.2% in end-of-life phases. For the same system in Bristol, emissions were 89%, 9% and 2%, respectively. A similar trend was observed for cavity wall systems in both locations. It was concluded that in each scenario, the ICF wall system performed better when compared to the cavity wall system. The results of the sensitivity analysis clearly show that the uncertainties relevant to the change of the thickness of the wall are quite tolerable: variable up to 5%, as far as energy and greenhouse emissions are concerned.

  2. Reliability Analysis of Geotechnical Failure Modes for Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    2000-01-01

    Vertical wall breakwaters are usually designed as concrete caissons placed on the top of a rubble mound foundation or a rubble bedding layer. The purpose of the breakwater is usually to protect the area behind the breakwater from being flooded by large waves. The area protected can for example be...... that the accepted probability of failure also varies considerably which also can be observed from the actual observed failure rates....... be a harbour of small or large importance, an important industrial area or a heavily populated coast line. This implies that vertical wall breakwaters are used under quite different conditions and therefore the consequences of a complete or partial failure also are very different. This implies...

  3. Tangential stress analysis of myocardial wall by finite element method

    Institute of Scientific and Technical Information of China (English)

    Guan Qiu; Jiang Cao; Wang Xiaoyan; Chen Shengyong; Guan Fang

    2011-01-01

    A novel method is presented to build the triangular surface model and calculate the tangential stress and strain of myocardial wall ,which can be further used to reflect the left ventricle twisting-a sensitive index to assess the systolic and diastolic function of heart. Firstly, a point distribution model is used to obtain the feature points of the ventricular surface in medical images. Secondly, the surface model is constructed by triangular mesh, and then the subdivision strategy is introduced to refine the model. Thirdly, plane projection and finite element method ( FEM ) are applied to calculate the tangential stress and strain. Finally, the distribution of tangential modulus of elasticity is discussed. The stimulation results show that the proposed method can be used to compute the tangential stress and strain of myocardial wall effectively and the computing result is consistent with the results mentioned in the literatures.

  4. Low-cost human motion capture system for postural analysis onboard ships

    Science.gov (United States)

    Nocerino, Erica; Ackermann, Sebastiano; Del Pizzo, Silvio; Menna, Fabio; Troisi, Salvatore

    2011-07-01

    The study of human equilibrium, also known as postural stability, concerns different research sectors (medicine, kinesiology, biomechanics, robotics, sport) and is usually performed employing motion analysis techniques for recording human movements and posture. A wide range of techniques and methodologies has been developed, but the choice of instrumentations and sensors depends on the requirement of the specific application. Postural stability is a topic of great interest for the maritime community, since ship motions can make demanding and difficult the maintenance of the upright stance with hazardous consequences for the safety of people onboard. The need of capturing the motion of an individual standing on a ship during its daily service does not permit to employ optical systems commonly used for human motion analysis. These sensors are not designed for operating in disadvantageous environmental conditions (water, wetness, saltiness) and with not optimal lighting. The solution proposed in this study consists in a motion acquisition system that could be easily usable onboard ships. It makes use of two different methodologies: (I) motion capture with videogrammetry and (II) motion measurement with Inertial Measurement Unit (IMU). The developed image-based motion capture system, made up of three low-cost, light and compact video cameras, was validated against a commercial optical system and then used for testing the reliability of the inertial sensors. In this paper, the whole process of planning, designing, calibrating, and assessing the accuracy of the motion capture system is reported and discussed. Results from the laboratory tests and preliminary campaigns in the field are presented.

  5. Analysis of ultra-narrow ferromagnetic domain walls

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, Catherine; Paul, David

    2012-01-10

    New materials with high magnetic anisotropy will have domains separated by ultra-narrow ferromagnetic walls with widths on the order of a few unit cells, approaching the limit where the elastic continuum approximation often used in micromagnetic simulations is accurate. The limits of this approximation are explored, and the static and dynamic interactions with intrinsic crystalline defects and external driving elds are modeled. The results developed here will be important when considering the stability of ultra-high-density storage media.

  6. Failure Analysis of 600 MW Supercritical Boiler Water Wall

    OpenAIRE

    Fu Huilin; Cai Zhengchun; Yan Xiaozhong; He Jinqiao; Zhou Yucai

    2013-01-01

    Boiler tube often causes abnormal boiler outage, bringing greater economic losses. This thesis mainly comes from the dynamics of boiler water, boiler furnace accident location of wall temperature distribution to explore the cause of the accident boiler. Calculation results show that the deformation will seriously reduce the boiler allowable maximum temperature difference between the screens. And the boiler is not over-temperature, low temperature difference between the screens, which have bur...

  7. Materials Analysis of Transient Plasma-Wall Interactions

    Science.gov (United States)

    2014-05-13

    model showing the importance sputter and re-deposition. plasma, pulsed plasma, directed energy, transient wall interaction, high energy density...each equipped with a 25kV copper- vapor thyratron start switch capable of sub-microsecond triggering resolution. Each start switch is paired with a...sample exposure positions within the plasma jet. The probe utilizes a PCB Piezotronics model 113B21 pressure sensor modified to work in the plasma jet

  8. A Survey of Advances in Vision-Based Human Motion Capture and Analysis

    DEFF Research Database (Denmark)

    Moeslund, Thomas B.; Hilton, Adrian; Krüger, Volker

    2006-01-01

    This survey reviews advances in human motion capture and analysis from 2000 to 2006, following a previous survey of papers up to 2000 Human motion capture continues to be an increasingly active research area in computer vision with over 350 publications over this period. A number of significant r...... actions and behavior. This survey reviews recent trends in video based human capture and analysis, as well as discussing open problems for future research to achieve automatic visual analysis of human movement....

  9. Motion synthesis and force distribution analysis for a biped robot.

    Science.gov (United States)

    Trojnacki, Maciej T; Zielińska, Teresa

    2011-01-01

    In this paper, the method of generating biped robot motion using recorded human gait is presented. The recorded data were modified taking into account the velocity available for robot drives. Data includes only selected joint angles, therefore the missing values were obtained considering the dynamic postural stability of the robot, which means obtaining an adequate motion trajectory of the so-called Zero Moment Point (ZMT). Also, the method of determining the ground reaction forces' distribution during the biped robot's dynamic stable walk is described. The method was developed by the authors. Following the description of equations characterizing the dynamics of robot's motion, the values of the components of ground reaction forces were symbolically determined as well as the coordinates of the points of robot's feet contact with the ground. The theoretical considerations have been supported by computer simulation and animation of the robot's motion. This was done using Matlab/Simulink package and Simulink 3D Animation Toolbox, and it has proved the proposed method.

  10. A first analysis of the mean motion of CHAMP

    Directory of Open Access Journals (Sweden)

    F. Deleflie

    2003-01-01

    Full Text Available The present study consists in studying the mean orbital motion of the CHAMP satellite, through a single long arc on a period of time of 200 days in 2001. We actually investigate the sensibility of its mean motion to its accelerometric data, as measures of the surface forces, over that period. In order to accurately determine the mean motion of CHAMP, we use “observed" mean orbital elements computed, by filtering, from 1-day GPS orbits. On the other hand, we use a semi-analytical model to compute the arc. It consists in numerically integrating the effects of the mean potentials (due to the Earth and the Moon and Sun, and the effects of mean surfaces forces acting on the satellite. These later are, in case of CHAMP, provided by an averaging of the Gauss system of equations. Results of the fit of the long arc give a relative sensibility of about 10-3, although our gravitational mean model is not well suited to describe very low altitude orbits. This technique, which is purely dynamical, enables us to control the decreasing of the trajectory altitude, as a possibility to validate accelerometric data on a long term basis.Key words. Mean orbital motion, accelerometric data

  11. A Coupled Analysis of Nonlinear Sloshing and Ship Motion

    Institute of Scientific and Technical Information of China (English)

    Shuo Huang; Wenyang Duan; Hao Zhang

    2012-01-01

    Nonlinear interactions among incident wave,tank-sloshing and floating body coupling motion are investigated.The fully nonlinear sloshing and body-surface nonlinear free surface hydrodynamics is simulated using a Non-Uniform Rational B-Spline (NURBS) higher-order panel method in time domain based on the potential theory.A robust and stable improved iterative procedure (Yan and Ma,2007) for floating bodies is used for calculating the time derivative of velocity potential and floating body motion.An energy dissipation condition based on linear theory adopted by Huang (2011) is developed to consider flow viscosity effects of sloshing flow in nonlinear model.A two-dimensional tank model test was performed to identify its validity.The present nonlinear coupling sway motion results are subsequently compared with the corresponding Rognebakke and Faltinsen (2003)'s experimental results,showing fair agreement.Thus,the numerical approach presented in this paper is expected to be very efficient and realistic in evaluating the coupling effects of nonlinear sloshing and body motion.

  12. THE STRUCTURAL ANALYSIS OF STEEL SILOS WITH CYLINDRICAL-WALL BEARING AND PROFILE-STEEL BEARING

    OpenAIRE

    Zhengjun Tang; Daibiao Zhou; Chenwei Peng; Wenping Wu

    2015-01-01

    The silos are widely used in bulk material in many fields such as agriculture, mining, chemical, electric power storage, etc. Thin metal cylindrical silo shells are vulnerable to buckling failure caused by the compressive wall friction force. In this paper, the structural analysis of two types of steel silo with cylindrical-wall bearing and profile-steel bearing is implemented by Abaqus finite element analysis. The results indicate that under the same loading conditions, steel silos with prof...

  13. Seismic Analysis of Shear-Wall Structures with Vertically Installed Dampers

    Institute of Scientific and Technical Information of China (English)

    Yang Jun; Li Li; Fan Aiwu

    2005-01-01

    Shear-wall structures are quite common in seismic areas because of their successful seismic behavior during severe earthquakes. But shear walls are prone to brittle failure. This study proposes a new method of vertically installed dampers (VID) to reduce the vibration in shear-wall structures. The motion characteristic of a vertical damping system is that every mass has horizontal and rotational displacements simultaneously. The establishment of dynamic equations should take into account the equilibrium conditions of both horizontal and rotational vibrations. Dynamic equilibrium equations of VID systems are derived from a model of a structure with VID. An example shear-wall structure, with and without VID, is studied. There are some changes in the characteristics of the maximum horizontal displacement response. Without dampers, the relative displacements between different floors in the shear wall increase with height. With dampers, the relative displacements are more uniformly distributed, and lateral displacements at the top and at the bottom are closer. When the damping coefficient is 1 000 kN·s/m, the numerical results reveal that the maximum horizontal displacement and the maximum rotational displacement of the top floor have reduced by 59.3 % and 54.8 % respectively.

  14. Three-dimensional Motion Analysis of the Ankle during Backward Walking.

    Science.gov (United States)

    Soda, Naoki; Ueki, Tsutomu; Aoki, Takaaki

    2013-06-01

    [Purpose] The purpose of this study was to perform kinematic and kinetic analyses of the ankle during both forward and backward walking using three-dimensional motion analysis. [Subjects] The subjects were 11 healthy adults. [Methods] Measurements of forward and backward walking motions were taken using a three-dimensional motion analysis device and 3 ground reaction force plates. The analysis segment was the standing phase and the items analyzed were walking time, maximum dorsal flexion of the ankle, maximum angle of plantar flexion, peak ankle power in the sagittal plane, workload of the ankle, and work rate. Statistical analysis consisted of comparisons using the t-test for each of the items measured during both forward and backward walking. [Results] The backward walking group had significantly lower ankle power, workload, and work rate. [Conclusion] The propulsive force in backward walking must come from some factor other than the ankle. The analysis of joint power is an important index for understanding the motion.

  15. Local collective motion analysis for multi-probe dynamic imaging and microrheology

    Science.gov (United States)

    Khan, Manas; Mason, Thomas G.

    2016-08-01

    Dynamical artifacts, such as mechanical drift, advection, and hydrodynamic flow, can adversely affect multi-probe dynamic imaging and passive particle-tracking microrheology experiments. Alternatively, active driving by molecular motors can cause interesting non-Brownian motion of probes in local regions. Existing drift-correction techniques, which require large ensembles of probes or fast temporal sampling, are inadequate for handling complex spatio-temporal drifts and non-Brownian motion of localized domains containing relatively few probes. Here, we report an analytical method based on local collective motion (LCM) analysis of as few as two probes for detecting the presence of non-Brownian motion and for accurately eliminating it to reveal the underlying Brownian motion. By calculating an ensemble-average, time-dependent, LCM mean square displacement (MSD) of two or more localized probes and comparing this MSD to constituent single-probe MSDs, we can identify temporal regimes during which either thermal or athermal motion dominates. Single-probe motion, when referenced relative to the moving frame attached to the multi-probe LCM trajectory, provides a true Brownian MSD after scaling by an appropriate correction factor that depends on the number of probes used in LCM analysis. We show that LCM analysis can be used to correct many different dynamical artifacts, including spatially varying drifts, gradient flows, cell motion, time-dependent drift, and temporally varying oscillatory advection, thereby offering a significant improvement over existing approaches.

  16. A Three-Dimensional Spatiotemporal Template for Interactive Human Motion Analysis

    Directory of Open Access Journals (Sweden)

    Alexandra Branzan Albu

    2007-08-01

    Full Text Available This paper describes a new three-dimensional spatiotemporal template, namely the Volumetric Motion History Image (VMHI, for the purpose of human motion analysis. Irregularities in human actions typically occur either in speed or orientation; they carry information about the balance and the confidence level of the human subject performing the activity. The proposed VMHI template handles successfully shortcomings of existing spatiotemporal templates related to motion self -occlusion and speed. Therefore, VMHI allows for interactive visualization, as well as quantification of motion performance. This study focuses on the analysis of sway and speed-related abnormalities, which are among the most common motion irregularities in the studied set of human actions.

  17. Contributions of domain wall motion to complex electromechanical coefficients of 0.62Pb(Mg1∕3Nb2∕3)O3–0.38PbTiO3 crystals

    Science.gov (United States)

    Wang, Zhu; Zhang, Rui; Sun, Enwei; Cao, Wenwu

    2010-01-01

    The loss behavior of 0.62Pb(Mg1∕3Nb2∕3)O3–0.38PbTiO3 (PMN-38%PT) ferroelectric single crystal poled along [001]c was investigated. It was found that the complex electromechanical coefficients and loss factors change dramatically at the coercive field Ec around 250 V∕mm, representing the intrinsic switching barrier. Since the energy loss is related to the domain wall motion, the imaginary parts of the electromechanical coefficients can be used to study the degree of domain wall motions in relaxor-based ferroelectric single crystals. Experimental results indicate that for this system, domain wall motion contributes significantly to the imaginary parts of electromechanical coefficients. In addition, [001]c poled PMN-38%PT single crystals have much larger mechanical loss factor compared to that of conventional single crystal like LiNbO3. This phenomenon is proved to be closely related to 90° domain wall motion in this crystal system. PMID:20145700

  18. Statistical analysis of motion contrast in optical coherence tomography angiography

    CERN Document Server

    Cheng, Yuxuan; Pan, Cong; Lu, Tongtong; Hong, Tianyu; Ding, Zhihua; Li, Peng

    2015-01-01

    Optical coherence tomography angiography (Angio-OCT), mainly based on the temporal dynamics of OCT scattering signals, has found a range of potential applications in clinical and scientific researches. In this work, based on the model of random phasor sums, temporal statistics of the complex-valued OCT signals are mathematically described. Statistical distributions of the amplitude differential (AD) and complex differential (CD) Angio-OCT signals are derived. The theories are validated through the flow phantom and live animal experiments. Using the model developed in this work, the origin of the motion contrast in Angio-OCT is mathematically explained, and the implications in the improvement of motion contrast are further discussed, including threshold determination and its residual classification error, averaging method, and scanning protocol. The proposed mathematical model of Angio-OCT signals can aid in the optimal design of the system and associated algorithms.

  19. Directivity in NGA earthquake ground motions: Analysis using isochrone theory

    Science.gov (United States)

    Spudich, P.; Chiou, B.S.J.

    2008-01-01

    We present correction factors that may be applied to the ground motion prediction relations of Abrahamson and Silva, Boore and Atkinson, Campbell and Bozorgnia, and Chiou and Youngs (all in this volume) to model the azimuthally varying distribution of the GMRotI50 component of ground motion (commonly called 'directivity') around earthquakes. Our correction factors may be used for planar or nonplanar faults having any dip or slip rake (faulting mechanism). Our correction factors predict directivity-induced variations of spectral acceleration that are roughly half of the strike-slip variations predicted by Somerville et al. (1997), and use of our factors reduces record-to-record sigma by about 2-20% at 5 sec or greater period. ?? 2008, Earthquake Engineering Research Institute.

  20. A Probabilistic Method for Motion Analysis of Caisson Breakwaters

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    It is assumed that, during the design period, the waves acting on breakwaters are divided into three types: standing wave, broken wave and breaking wave,and the wave heights fit the Rayleigh distribution while the water depths, wave periods and duration of breaking wave impact force fit normal distribution. Based on the random samples of water depths, wave heights, wave periods and duration of breaking wave impact force, the types of waves acting on breakwaters are distinguished and the time-history model of the wave force is determined. The motions of caisson breakwaters under the wave force are simulated by a dynamic numerical model and the statistic characteristics of the dynamic responses are analyzed with the Monte Carlo method. A probabilistic procedure to analyze the motion of the breakwater is developed therein. The procedure is illustrated by an example.

  1. Virtual Robot Teaching Based on Motion Analysis and Hand Manipulability for Multi-Fingered Robot

    National Research Council Canada - National Science Library

    KAWASAKI, Haruhisa; FURUKAWA, Tomohir; UEKI, Satoshi; MOURI, Tetsuya

    2009-01-01

    A virtual robot teaching system, consisting of human demonstration and motion-intention analysis in a virtual reality environment, is an advanced form of automatic programming for multi-fingered robots...

  2. Reliability of 3D upper limb motion analysis in children with obstetric brachial plexus palsy.

    Science.gov (United States)

    Mahon, Judy; Malone, Ailish; Kiernan, Damien; Meldrum, Dara

    2017-03-01

    Kinematics, measured by 3D upper limb motion analysis (3D-ULMA), can potentially increase understanding of movement patterns by quantifying individual joint contributions. Reliability in children with obstetric brachial plexus palsy (OBPP) has not been established.

  3. Motion Analysis of Live Objects by Super-Resolution Fluorescence Microscopy

    Directory of Open Access Journals (Sweden)

    Chunyan Yao

    2012-01-01

    Full Text Available Motion analysis plays an important role in studing activities or behaviors of live objects in medicine, biotechnology, chemistry, physics, spectroscopy, nanotechnology, enzymology, and biological engineering. This paper briefly reviews the developments in this area mostly in the recent three years, especially for cellular analysis in fluorescence microscopy. The topic has received much attention with the increasing demands in biomedical applications. The tasks of motion analysis include detection and tracking of objects, as well as analysis of motion behavior, living activity, events, motion statistics, and so forth. In the last decades, hundreds of papers have been published in this research topic. They cover a wide area, such as investigation of cell, cancer, virus, sperm, microbe, karyogram, and so forth. These contributions are summarized in this review. Developed methods and practical examples are also introduced. The review is useful to people in the related field for easy referral of the state of the art.

  4. Finite Element Analysis of Composite Hardened Walls Subjected to Blast Loads

    Directory of Open Access Journals (Sweden)

    Girum S. Urgessa

    2009-01-01

    Full Text Available Problem statement: There is currently no standard design guideline to determine the number of composites needed to retrofit masonry walls in order to withstand a given explosion. Past design approaches were mainly based on simplified single-degree-of-freedom analysis. A finite element analysis was conducted for concrete masonry walls hardened with composites and subjected to short duration blast loads. Approach: The analysis focused on displacement time history responses which form the basis for retrofit design guidelines against blast loadings. The blast was determined from 0.5 kg equivalent TNT explosive at 1.83 m stand-off distance to simulate small mailroom bombs. Two and four layered retrofitted walls were investigated. Uncertainties in the finite model analysis of walls such as pressure distributions, effect of mid height explosive bursts versus near the ground explosive bursts and variations in modulus of elasticity of the wall were presented. Results: Uniformly distributed blast loads over the retrofitted wall height produced a small difference in peak displacement results when compared to the non-uniform pressure distribution. Ground explosive burst was shown to produce a 62.7% increase in energy and a higher peak displacement response when compared to mid-height explosive burst. Conclusion: The parametric study on the variation of modulus of elasticity of concrete masonry showed no significant effect on peak displacement affirming the use of the resistance deflection contribution of the composite in retrofit designs.

  5. Cell wall staining with Trypan blue enables quantitative analysis of morphological changes in yeast cells

    DEFF Research Database (Denmark)

    Liesche, Johannes; Marek, Magdalena; Günther-Pomorski, Thomas

    2015-01-01

    with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain...... Calcofluor White. Trypan Blue staining facilitated quantification of cell size and cell wall volume when utilizing the optical sectioning capacity of a confocal microscope. This enabled the quantification of morphological changes during growth under anaerobic conditions and in the presence of chemicals...

  6. THE STRUCTURAL ANALYSIS OF STEEL SILOS WITH CYLINDRICAL-WALL BEARING AND PROFILE-STEEL BEARING

    Directory of Open Access Journals (Sweden)

    Zhengjun Tang

    2015-04-01

    Full Text Available The silos are widely used in bulk material in many fields such as agriculture, mining, chemical, electric power storage, etc. Thin metal cylindrical silo shells are vulnerable to buckling failure caused by the compressive wall friction force. In this paper, the structural analysis of two types of steel silo with cylindrical-wall bearing and profile-steel bearing is implemented by Abaqus finite element analysis. The results indicate that under the same loading conditions, steel silos with profile-steel bearing and cylindrical-Wall bearing have similar values in Mises stress, but the steel silo with profile-steel bearing has a smaller radial displacement and a better capability of buckling resistance. Meanwhile, the total steel volumes reduced 8.0% comparing to the steel silo with cylindrical-wall bearing. Therefore, steel soil with profile-steel bearing not only has a less steel volumes but also a good stability.

  7. Bifurcation analysis and stability design for aircraft longitudinal motion with high angle of attack

    Directory of Open Access Journals (Sweden)

    Xin Qi

    2015-02-01

    Full Text Available Bifurcation analysis and stability design for aircraft longitudinal motion are investigated when the nonlinearity in flight dynamics takes place severely at high angle of attack regime. To predict the special nonlinear flight phenomena, bifurcation theory and continuation method are employed to systematically analyze the nonlinear motions. With the refinement of the flight dynamics for F-8 Crusader longitudinal motion, a framework is derived to identify the stationary bifurcation and dynamic bifurcation for high-dimensional system. Case study shows that the F-8 longitudinal motion undergoes saddle node bifurcation, Hopf bifurcation, Zero-Hopf bifurcation and branch point bifurcation under certain conditions. Moreover, the Hopf bifurcation renders series of multiple frequency pitch oscillation phenomena, which deteriorate the flight control stability severely. To relieve the adverse effects of these phenomena, a stabilization control based on gain scheduling and polynomial fitting for F-8 longitudinal motion is presented to enlarge the flight envelope. Simulation results validate the effectiveness of the proposed scheme.

  8. Real-time marker-free motion capture system using blob feature analysis

    Science.gov (United States)

    Park, Chang-Joon; Kim, Sung-Eun; Kim, Hong-Seok; Lee, In-Ho

    2005-02-01

    This paper presents a real-time marker-free motion capture system which can reconstruct 3-dimensional human motions. The virtual character of the proposed system mimics the motion of an actor in real-time. The proposed system captures human motions by using three synchronized CCD cameras and detects the root and end-effectors of an actor such as a head, hands, and feet by exploiting the blob feature analysis. And then, the 3-dimensional positions of end-effectors are restored and tracked by using Kalman filter. At last, the positions of the intermediate joint are reconstructed by using anatomically constrained inverse kinematics algorithm. The proposed system was implemented under general lighting conditions and we confirmed that the proposed system could reconstruct motions of a lot of people wearing various clothes in real-time stably.

  9. One hybrid model combining singular spectrum analysis and LS + ARMA for polar motion prediction

    Science.gov (United States)

    Shen, Yi; Guo, Jinyun; Liu, Xin; Wei, Xiaobei; Li, Wudong

    2017-01-01

    Accurate real-time polar motion parameters play an important role in satellite navigation and positioning and spacecraft tracking. To meet the needs for real-time and high-accuracy polar motion prediction, a hybrid model that integrated singular spectrum analysis (SSA), least-squares (LS) extrapolation and an autoregressive moving average (ARMA) model was proposed. SSA was applied to separate the trend, the annual and the Chandler components from a given polar motion time series. LS extrapolation models were constructed for the separated trend, annual and Chandler components. An ARMA model was established for a synthetic sequence that contained the remaining SSA component and the residual series of LS fitting. In applying this hybrid model, multiple sets of polar motion predictions with lead times of 360 days were made based on an IERS 08 C04 series. The results showed that the proposed method could effectively predict the polar motion parameters.

  10. A new analysis methodology for the motion of self-propelled particles and its application

    Science.gov (United States)

    Byun, Young-Moo; Lammert, Paul; Crespi, Vincent

    2011-03-01

    The self-propelled particle (SPP) on the microscale in the solution is a growing field of study, which has a potential to be used for nanomedicine and nanorobots. However, little detailed quantitative analysis on the motion of the SPP has been performed so far because its self-propelled motion is strongly coupled to Brownian motion, which makes the extraction of intrinsic propulsion mechanisms problematic, leading to inconsistent conclusions. Here, we present a novel way to decompose the motion of the SPP into self-propelled and Brownian components; accurate values for self-propulsion speed and diffusion coefficients of the SPP are obtained for the first time. Then, we apply our analysis methodology to ostensible chemotaxis of SPP, and reveal the actual (non-chemotactic) mechanism of the phenomenon, demonstrating that our analysis methodology is a powerful and reliable tool.

  11. Spacecraft motion analysis about rapid rotating small body

    Institute of Scientific and Technical Information of China (English)

    史雪岩; 崔祜涛; 崔平远; 栾恩杰

    2003-01-01

    The orbital dynamics equation of a spacecraft around an irregular sphere small body is established based on the small body' s gravitational potential approximated with a tri-axial ellipsoid. According to the Jacobi integral constant, the spacecraft zero-velocity curves in the vicinity of the small body is described and feasible motion region is analyzed. The limited condition and the periapsis radius corresponding to different eccentricity against impact surface are presented. The stability of direct and retrograde equator orbits is analyzed based on the perturbation solutions of mean orbit elements.

  12. MECHANISM DESIGN AND MOTION ANALYSIS OF A SPHERICAL MOBILE ROBOT

    Institute of Scientific and Technical Information of China (English)

    Zhan Qiang; Jia Chuan; Ma Xiaohui; Zhai Yutao

    2005-01-01

    A new spherical mobile robot BHQ-1 is designed. The spherical robot is driven by two internally mounted motors that induce the ball to move straight and turn around on a flat surface. A dynamic model of the robot is developed with Lagrange method and factors affecting the driving torque of two motors are analyzed. The relationship between the turning radius of the robot and the length of two links is discussed in order to optimize its mechanism design. Simulation and experimental results demonstrate the good controllability and motion performance of BHQ-1.

  13. An approximate method for lateral stability analysis of wall-frame buildings including shear deformations of walls

    Indian Academy of Sciences (India)

    Kanat Burak Bozdogan; Duygu Ozturk

    2010-06-01

    This study presents an approximate method based on the continuum approach and transfer matrix method for lateral stability analysis of buildings. In this method, the whole structure is idealized as an equivalent sandwich beam which includes all deformations. The effect of shear deformations of walls has been taken into consideration and incorporated in the formulation of the governing equations. Initially the stability differential equation of this equivalent sandwich beam is presented, and then shape functions for each storey is obtained by the solution of the differential equations. By using boundary conditions and stability storey transfer matrices obtained by shape functions, system buckling load can be calculated. To verify the presented method, four numerical examples have been solved. The results of the samples demonstrate the agreement between the presented method and the other methods given in the literature.

  14. Targeted principle component analysis: A new motion artifact correction approach for near-infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Meryem A. Yücel

    2014-03-01

    Full Text Available As near-infrared spectroscopy (NIRS broadens its application area to different age and disease groups, motion artifacts in the NIRS signal due to subject movement is becoming an important challenge. Motion artifacts generally produce signal fluctuations that are larger than physiological NIRS signals, thus it is crucial to correct for them before obtaining an estimate of stimulus evoked hemodynamic responses. There are various methods for correction such as principle component analysis (PCA, wavelet-based filtering and spline interpolation. Here, we introduce a new approach to motion artifact correction, targeted principle component analysis (tPCA, which incorporates a PCA filter only on the segments of data identified as motion artifacts. It is expected that this will overcome the issues of filtering desired signals that plagues standard PCA filtering of entire data sets. We compared the new approach with the most effective motion artifact correction algorithms on a set of data acquired simultaneously with a collodion-fixed probe (low motion artifact content and a standard Velcro probe (high motion artifact content. Our results show that tPCA gives statistically better results in recovering hemodynamic response function (HRF as compared to wavelet-based filtering and spline interpolation for the Velcro probe. It results in a significant reduction in mean-squared error (MSE and significant enhancement in Pearson's correlation coefficient to the true HRF. The collodion-fixed fiber probe with no motion correction performed better than the Velcro probe corrected for motion artifacts in terms of MSE and Pearson's correlation coefficient. Thus, if the experimental study permits, the use of a collodion-fixed fiber probe may be desirable. If the use of a collodion-fixed probe is not feasible, then we suggest the use of tPCA in the processing of motion artifact contaminated data.

  15. Strong Ground-Motion Prediction in Seismic Hazard Analysis: PEGASOS and Beyond

    Science.gov (United States)

    Scherbaum, F.; Bommer, J. J.; Cotton, F.; Bungum, H.; Sabetta, F.

    2005-12-01

    The SSHAC Level 4 approach to probabilistic seismic hazard analysis (PSHA), which could be considered to define the state-of-the-art in PSHA using multiple expert opinions, has been fully applied only twice, firstly in the multi-year Yucca Mountain study and subsequently (2002-2004) in the PEGASOS project. The authors of this paper participated as ground-motion experts in this latter project, the objective of which was comprehensive seismic hazard analysis for four nuclear power plant sites in Switzerland, considering annual exceedance frequencies down to 1/10000000. Following SSHAC procedure, particular emphasis was put on capturing both the aleatory and epistemic uncertainties. As a consequence, ground motion prediction was performed by combining several empirical ground motion models within a logic tree framework with the weights on each logic tree branch expressing the personal degree-of-belief of each ground-motion expert. In the present paper, we critically review the current state of ground motion prediction methodology in PSHA in particular for regions of low seismicity. One of the toughest lessons from PEGASOS was that in systematically and rigorously applying the laws of uncertainty propagation to all of the required conversions and adjustments of ground motion models, a huge price has to be paid in an ever-growing aleatory variability. Once this path has been followed, these large sigma values will drive the hazard, particularly for low annual frequencies of exceedance. Therefore, from a post-PEGASOS perspective, the key issues in the context of ground-motion prediction for PSHA for the near future are to better understand the aleatory variability of ground motion and to develop suites of ground-motion prediction equations that employ the same parameter definitions. The latter is a global rather than a regional challenge which might be a desirable long-term goal for projects similar to the PEER NGA (Pacific Earthquake Engineering Research Center, Next

  16. Three-dimensional analysis of relationship between relative orientation and motion modes

    Institute of Scientific and Technical Information of China (English)

    Fan Shijie a; Fan Hongqi a; Xiao Huaitie a; Fan Jianpeng b; Fu Qiang a

    2014-01-01

    Target motion modes have a close relationship with the relative orientation of missile-to-target in three-dimensional highly maneuvering target interception. From the perspective of rela-tionship between the sensor coordinate system and the target body coordinate system, a basic model of sensor is stated and the definition of relative angular velocity between the two coordinate systems is introduced firstly. Then, the three-dimensional analytic expressions of relative angular velocity for different motion modes are derived and simplified by analyzing the influences of target centroid motion, rotation around centroid and relative motion. Finally, the relationships of the relative angular velocity directions and values with motion modes are discussed. Simulation results validate the rationality of the theoretical analysis. It is demonstrated that there are significant differences of the relative orientation in different motion modes which include luxuriant information about motion modes. The conclusions are significant for the research of motion mode identification, maneuver detection, maneuvering target tracking and interception using target signatures.

  17. Three-dimensional analysis of relationship between relative orientation and motion modes

    Directory of Open Access Journals (Sweden)

    Fan Shijie

    2014-12-01

    Full Text Available Target motion modes have a close relationship with the relative orientation of missile-to-target in three-dimensional highly maneuvering target interception. From the perspective of relationship between the sensor coordinate system and the target body coordinate system, a basic model of sensor is stated and the definition of relative angular velocity between the two coordinate systems is introduced firstly. Then, the three-dimensional analytic expressions of relative angular velocity for different motion modes are derived and simplified by analyzing the influences of target centroid motion, rotation around centroid and relative motion. Finally, the relationships of the relative angular velocity directions and values with motion modes are discussed. Simulation results validate the rationality of the theoretical analysis. It is demonstrated that there are significant differences of the relative orientation in different motion modes which include luxuriant information about motion modes. The conclusions are significant for the research of motion mode identification, maneuver detection, maneuvering target tracking and interception using target signatures.

  18. Detecting cause of dislocation after total hip arthroplasty by patient-specific four-dimensional motion analysis.

    Science.gov (United States)

    Miki, Hidenobu; Sugano, Nobuhiko; Yonenobu, Kazuo; Tsuda, Kosuke; Hattori, Maki; Suzuki, Naoki

    2013-02-01

    Dislocation is a major complication after total hip arthroplasty. Prosthesis impingement is considered to be an important cause of dislocation because impingement marks are more frequently found on retrieved cups or liners in patients who have undergone revision surgery because of dislocation (80%-94%) than in those who have undergone reoperation for other reasons (51%-56%). However, it remains a question whether impingement marks are the cause of dislocation or are instead its result. To clarify the issue, it is necessary to confirm noninvasively whether the point of impingement matches the patient's hip position when dislocation occurs. Using four-dimensional patient-specific analysis, we recorded prosthesis impingement in 10 hips with instability after primary total hip arthroplasty when the patients reproduced the dislocation-causing motion. We found prosthesis impingement to be related to at least instability in 6 of 10 hips with dislocation after primary total hip arthroplasty and in 4 of 4 hips that underwent revision surgery for recurrent dislocation. All impingements occurred between the anterior wall of the liner and the stem neck in posterior dislocation and between the posterior wall of the liner and the stem neck in anterior dislocation. Revision surgery in 1 of those 4 hips revealed 2 impingement marks on the retrieved liner that closely matched the prosthesis impingement point and the dislocation pathway of the metal head on the liner that were detected earlier during motion analysis. Prosthesis impingement is an important factor in dislocation after total hip arthroplasty. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Cell wall staining with Trypan Blue enables quantitative analysis of morphological changes in yeast cells

    Directory of Open Access Journals (Sweden)

    Johannes eLiesche

    2015-02-01

    Full Text Available Yeast cells are protected by a cell wall that plays an important role in the exchange of substances with the environment. The cell wall structure is dynamic and can adapt to different physiological states or environmental conditions. For the investigation of morphological changes, selective staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain Calcofluor White. Trypan Blue staining facilitated quantification of cell size and cell wall volume when utilizing the optical sectioning capacity of a confocal microscope. This enabled the quantification of morphological changes during growth under anaerobic conditions and in the presence of chemicals, demonstrating the potential of this approach for morphological investigations or screening assays.

  20. FINITE ELEMENT ANALYSIS OF JNES/NUPEC SEISMIC SHEAR WALL CYCLIC AND SHAKING TABLE TEST DATA.

    Energy Technology Data Exchange (ETDEWEB)

    XU,J.; NIE, J.; HOFMAYER, C.; ALI, S.

    2007-04-12

    This paper describes a finite element analysis to predict the JNES/NUPEC cyclic and shaking table RC shear wall test data, as part of a collaborative agreement between the U.S. NRC and JNES to study seismic issues important to the safe operation of commercial nuclear power plant (NPP) structures, systems and components (SSC). The analyses described in this paper were performed using ANACAP reinforced concrete models. The paper describes the ANACAP analysis models and discusses the analysis comparisons with the test data. The ANACAP capability for modeling nonlinear cyclic characteristics of reinforced concrete shear wall structures was confirmed by the close comparisons between the ANACAP analysis results and the JNES/NUPEC cyclic test data. Reasonable agreement between the analysis results and the test data was demonstrated for the hysteresis loops and the shear force orbits, in terms of both the overall shape and the cycle-to-cycle comparisons. The ANACAP simulation analysis of the JNES/NUPEC shaking table test was also performed, which demonstrated that the ANACAP dynamic analysis with concrete material model is able to capture the progressive degrading behavior of the shear wall as indicated from the test data. The ANACAP analysis also predicted the incipient failure of the shear wall, reasonably close to the actual failure declared for the test specimen. In summary, the analyses of the JNES/NUPEC cyclic and shaking table RC shear wall tests presented in this paper have demonstrated the state-of-the-art analysis capability for determining the seismic capacity of RC shear wall structures.

  1. M型超声检测腹主动脉前后壁运动的初步研究%Primary studies of anteroposterior abdominal aortic wall motion with M-mode ultrasound

    Institute of Scientific and Technical Information of China (English)

    辛群; 蔡珠虹; 包俊敏; 梅志军; 景在平

    2011-01-01

    Objective To find out the characteristics of anteroposterior abdominal aortic wall motion and to consider the potential implications of such variations. Methods M-mode ultrasound was used to measure abdominal aortic wall motion in human (n=20) and 2 animal species [dogs (n=8), and pigs (n=5)]. Anterior wall displacement (da),posterior wall displacement (dp), and diastolic diameter (Da) were measured. The ratio of displacement to the diameter was calculated (da/Dd. and dp/Dd). Results Aortic diameter varied from to (6.34±0.84) mm (dog) to (13.76±1.11) mm (human).Anterior wall displacement was about 3 times greater than the posterior among the species studied. The ratio of wall displacement to diastolic diameter were similar for the anterior and posterior walls. Wall displacement increased linearly with the diameter. Conclusions Abdominal aortic wall dynamics are similar in humans and animals regardless of the aortic size, with more anterior than posterior wall motion. These data suggest increased .dynamic strain of the anterior wall,which may help explain why human abdominal aortic aneurysms initially develop anteriorly. Haemodynamies plays an important role in the abdominal aortic aneurysm pathogenesis.%目的:应用M型超声观测正常腹主动脉前后壁运动的特征.方法:采集健康人组、健康犬组、健康猪组腹主动脉的M型超声图像,测量动脉前壁和后壁振幅(da和dP)、舒张期动脉直径(Dd),取其平均值;并分别计算各组数值:前壁振幅/舒张期动脉直径(da/Dd),后壁振幅/舒张期动脉直径(dp/Dd).结果:三组结果显示腹主动脉前壁振幅高于后壁振幅,差异有统计学意义(P<0.01).各组中管壁振幅与管径呈正相关.da/Dd和dp/Dd组间比较,差异无统计学意义.结论:正常腹主动脉前、后壁的运动差异与腹主动脉瘤的形成有一定关系,提示血液动力学因素在腹主动脉瘤发病机制中起着重要作用.

  2. Inertial Sensor-Based Motion Analysis of Lower Limbs for Rehabilitation Treatments

    Directory of Open Access Journals (Sweden)

    Tongyang Sun

    2017-01-01

    Full Text Available The hemiplegic rehabilitation state diagnosing performed by therapists can be biased due to their subjective experience, which may deteriorate the rehabilitation effect. In order to improve this situation, a quantitative evaluation is proposed. Though many motion analysis systems are available, they are too complicated for practical application by therapists. In this paper, a method for detecting the motion of human lower limbs including all degrees of freedom (DOFs via the inertial sensors is proposed, which permits analyzing the patient’s motion ability. This method is applicable to arbitrary walking directions and tracks of persons under study, and its results are unbiased, as compared to therapist qualitative estimations. Using the simplified mathematical model of a human body, the rotation angles for each lower limb joint are calculated from the input signals acquired by the inertial sensors. Finally, the rotation angle versus joint displacement curves are constructed, and the estimated values of joint motion angle and motion ability are obtained. The experimental verification of the proposed motion detection and analysis method was performed, which proved that it can efficiently detect the differences between motion behaviors of disabled and healthy persons and provide a reliable quantitative evaluation of the rehabilitation state.

  3. Isogeometric analysis for thin-walled composite structures

    NARCIS (Netherlands)

    Guo, Y.

    2016-01-01

    The conceptual ideas behind isogeometric analysis (IGA) are aimed at unifying computer aided design (CAD) and finite element analysis (FEA). Isogeometric analysis employs the non-uniform rational B-spline functions (NURBS) used for the geometric description of a structure to approximate its physical

  4. Clinical analysis of abdominal wall endometriosis in 101 cases

    Institute of Scientific and Technical Information of China (English)

    Cheng Ning-hai; Zhu Lan; Lang Jing-he; Liu Zhu-feng; Sun Da-wei; Leng Jin-hua

    2006-01-01

    Objective: To review the clinical characteristics, treatment and prognoses of abdominal wall endometriosis(AWE).Methods: A retrospective study of 101 cases of AWE from 1992 to 2005 at Obstetric and Gynecologic Department of Peking Union Medical College Hospital was performed. Ninety-eight patients had a history of caesarean section. The mean age of the patients was (33.3±4.8) years and the average size of the mass was 1.5 cm. Abdominal wall mass associated pain during the menstrual cycle was noticed in 89.8% of the patients. The occurrence of AWE after caesarean section was 0.05% at our hospital. In patients without pelvic endometriosis or adenomyosis, 20.5% were presented with high CA125 >35 U/ml and the highest one was 93.4 U/ml. 92.1% of patients were diagnosed before surgery. 4 patients were administrated first in General Surgical Department with painless abdominal mass. Medication was adopted in 16 cases pre-operatively and 14 cases post-operatively.Results: The mean size of the resected mass was 4.2 cm, significantly larger than the estimation with palpation or ultrasonography, which was 0.8-1.2 cm (P=0.006, P<0.001). Pelvic endometriosis or adenomyosis was detected during the operation in 13 patients. One patient was diagnosed as atypical endometriosis by pathological examination in the beginning but transformed to be sarcoma finally. Ten patients recurred after surgery. 2 of them received medication and 5 of them received second operation.Conclusions: Ultrasonography can be used to evaluate the size of the mass and the infiltrative scope pre-operation. The serum CA125 is not specific for diagnosis of AWE. Complete eradication of the lesion with at least 1 cm beyond the edge of the mass is recommended as the primary treatment. Eradication should be considered also in recurrent cases. It may transform to malignant lesions after multiple recurrence.

  5. Blast testing and analysis of composite steel stud wall panels

    Energy Technology Data Exchange (ETDEWEB)

    Wesevich, J.W.; Lowak, M.J.; Hu, W.; Bingham, B.L. [Baker Engineering and Risk Consultants Inc., San Antonio, TX (United States); Hallisy, J. [Fiberwrap Composite Technologies, Calverton, NY (United States); Calcetas, P. [Lafarge North America, Concord, ON (Canada)

    2007-07-01

    This paper described a novel modular blast resistant composite steel stud wall panel system. The system was manufactured by casting steel studs with thin, high-strength concrete. Ten composite panel design specimens were evaluated and tested at a shock tube test facility. Specimens included both 12 and 16 gauge 6 inch cold-formed double or single studs spaced at either 12 or 16 inches on center. Samples also included both steam and ambient cured concretes with steel or organic fibers ranging in thickness between 1 and 2 inches. A welded wire mesh within the concrete layer was used to provide composite action. Results of the blast tests showed that the composite panels achieved minimal damage levels under applied blast loads, which ranged from between 15.9 psi to 205 psi. Peak dynamic reflections ranged from between 2.75 increase to 12 inches. It was concluded that finite element models and single-degree-of-freedom (SDOF) analyses showed good agreement with the experimental studies.

  6. Radiologic analysis of cecal filling defects and local wall displacement

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. I.; Suh, J. S.; Kim, G. E.; Park, C. Y. [Yonsei University, College of Medicine, Seoul (Korea, Republic of)

    1981-09-15

    It has long been accepted that cecum and ileocecal valve are prime important area in GI roentgenology because of variety and frequency of primary and secondary disease involvement. However, precise preoperative diagnosis is still debatable roentrenologically. It is necessary to use the more descriptive terms and systemic approach for roentgenologic diagnosis in this area. Authors analyzed pathologically verified 54 cases of cecal lesion by double contrast colon examination at Yonsei University Medical College Severance Hospital from January '75 to September '80. Of the distribution of diseases, pericecal abscess (16/54; 29.6%) was most common, and followed by intestinal tuberculosis (9/54; 16.6%), and carcinoma (9/54; 16.6%) etc. The ratio of male and female was 2.18: 1 and peak incidence was above 4th decade. The majority of cases show right lower quadrant pain and palpable mass as clinical manifestation. Of the radiologic findings, abnormality in appendix such as nonfilling or irregular filling of barium suggest pericecal abscess, mucocele and less frequently adenocarcinoma of cecum, and characteristically pericecal abscess show rather smooth displacement of medial wall of cecum, but abrupt transition of lesion is shown in adenocarcinoma. Irritability and shortening of cecum, and fixation and speculation of terminal ileum were frequently found in inflammatory conditions such as pericecal abscess, intestinal tuberculosis and chronic nonspecific inflammation. Cecal lesion associated with involvement of ileocecal value were noted in intestinal tuberculosis, lymphoma and adenocarcinoma.

  7. New analysis and performance of a wall-current monitor

    Energy Technology Data Exchange (ETDEWEB)

    Suwada, T.; Urano, T.; Kobayashi, H. [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan); Tamiya, K.; Asami, A. [Naruto University of Education, Takashima, Naruto-cho, Naruto-shi 772 (Japan)

    1997-09-01

    A new wall-current monitor has been developed in order to reinforce the beam-monitoring system in the PF 2.5-GeV linac for the KEK B-Factory. A prototype monitor was tested for its performance and characteristics. The experimental results in terms of both bench tests and beam tests by single-bunch electron beams were analyzed on the basis of equivalent-circuit models. The frequency response of the monitor agreed well with a lumped equivalent-circuit model for both time- and frequency-domain measurements. The position dependence and its frequency characteristics of the monitor also agreed well with a distributed equivalent-circuit model for both time- and frequency-domain measurements. The rise time of the monitor was about 3 ns, which indicated a poor response for short-pulse beams (<1) ns. The reason could be attributed to the stray inductance of the ceramic solid resistor and not very good frequency response of the ferrite core. (orig.).

  8. Centrifuge modelling and finite element analysis of reinforced fly ash walls

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, J.N.; Shaikh, Z. [Indian Institute of Technology, Bombay (India). Dept.of Civil Engineering

    2003-07-01

    Centrifuge modeling of unreinforced and reinforced fly ash wall was done with varying water content to study the failure pattern and their behaviour. Fly ash was from the ash disposal pond of Koradi Thermal Power Plant (KTPP) in Nagpur, India. The fly ash walls without reinforcement are liable to fail and sudden failure of slopes have been noticed. Unreinforced fly ash wall shows a sharp decrease in the strength for a water content on the higher side of optimum moisture content. Fly ash walls reinforced with geotextiles performed satisfactorily even at very high rpm. A non-linear finite element analysis was carried out to evaluate the distribution of stresses and deformations. The lateral deformation obtained by the finite element analysis and the centrifuge modeling is found to be sufficiently less than the permissible limit. The lateral deformations of the reinforced retaining wall does not decrease appreciably with increase in the stiffness of reinforcement but decreases as the modulus of the backfill soil increases. More research is required on the long-term mechanical and chemical behaviour of the fly ash material and the long-term stability of the reinforced fly ash walls. 14 refs., 3 tabs.

  9. Crack propagation analysis of welded thin-walled joints using boundary element method

    Science.gov (United States)

    Mashiri, F. R.; Zhao, Xiao-Ling; Grundy, P.

    Tube-to-plate nodal joints under cyclic bending are widely used in the road transport and agricultural industry. The square hollow sections (SHS) used in these constructions are thin-walled and cold formed, and they have thicknesses of less than 4mm. Some fatigue failures have been observed. The weld undercut may affect the fatigue life of welded tubular joints especially for thin-walled sections. The undercut dimensions were measured using the silicon imprint technique. Modelling of thin-walled cruciform joints, as a simplification of welded tubular joints, is described in this paper to determine the effect of weld undercut on fatigue propagation life. The Boundary Element Analysis System Software (BEASY) is used. The results of the effect of weld toe undercut from this analysis are compared with results from previous research to determine the comparative reduction in fatigue life between thin-walled joints (T=3mm) and those made of thicker sections (T=20mm). The loss in fatigue strength of the thin-walled joints is found to be relatively more than that for thicker walled joints. A 3D model of a tube to plate T-joint is also modelled using the boundary element software, BEASY. The nodal joint consists of a square hollow section, 50×50×3 SHS, fillet welded to a 10-mm thick plate, and subjected to cyclic bending stress. Fatigue analyses are carried out and the results are compared with the only available S-N design curve.

  10. Statistical Analysis of Conductor Motion in LHC Superconducting Dipole Magnets

    CERN Document Server

    Calvi, M; Pugnat, P; Siemko, A

    2004-01-01

    Premature training quenches are usually caused by the transient energy release within the magnet coil as it is energised. The dominant disturbances originate in cable motion and produce observable rapid variation in voltage signals called spikes. The experimental set up and the raw data treatment to detect these phenomena are briefly recalled. The statistical properties of different features of spikes are presented like for instance the maximal amplitude, the energy, the duration and the time correlation between events. The parameterisation of the mechanical activity of magnets is addressed. The mechanical activity of full-scale prototype and first preseries LHC dipole magnets is analysed and correlations with magnet manufacturing procedures and quench performance are established. The predictability of the quench occurrence is discussed and examples presented.

  11. Motion analysis of optically trapped particles and cells using 2D Fourier analysis

    DEFF Research Database (Denmark)

    Kristensen, Martin Verner; Ahrendt, Peter; Lindballe, Thue Bjerring;

    2012-01-01

    Motion analysis of optically trapped objects is demonstrated using a simple 2D Fourier transform technique. The displacements of trapped objects are determined directly from the phase shift between the Fourier transform of subsequent images. Using end-and side-view imaging, the stiffness...... of the trap is determined in three dimensions. The Fourier transform method is simple to implement and applicable in cases where the trapped object changes shape or where the lighting conditions change. This is illustrated by tracking a fluorescent particle and a myoblast cell, with subsequent determination...

  12. Motion Law Analysis and Structural Optimization of the Ejection Device of Tray Seeder

    Science.gov (United States)

    Luo, Xin; Hu, Bin; Dong, Chunwang; Huang, Lili

    An ejection mechanism consisting four reset springs, an electromagnet and a seed disk was designed for tray seeder. The motion conditions of seeds in the seed disk were theoretical analyzed and intensity and height of seed ejection were calculated. The motions of the seeds and seed disk were multi-body dynamic simulated using Cosmos modules plug-in SolidWorks software package. The simulation results showed the consistence with the theoretical analysis.

  13. Investigation of the Behavior of Steel Shear Walls Using Finite Elements Analysis

    Directory of Open Access Journals (Sweden)

    K. Abubakri

    2016-10-01

    Full Text Available Currently, steel shear walls are considered by engineers as an economic method against lateral loads imposed by wind and earthquake in tall structures. Accordingly, there is a growing need to develop accurate methods alongside approximation methods to estimate the behavior of these structural elements. The finite element technique is one of the strongest numerical methods in analysis of solid mechanics problems. Finite element analysis however requires high technical knowledge of the behavioral models of materials. Therefore, it is less used by designers for certain structural elements such as steel shear walls. This study examines the failure mechanism of steel shear walls using finite elements analysis and validates this modeling by comparing the results with experimental studies.

  14. Seismic displacement of gravity retaining walls

    Directory of Open Access Journals (Sweden)

    Kamal Mohamed Hafez Ismail Ibrahim

    2015-08-01

    Full Text Available Seismic displacement of gravity walls had been studied using conventional static methods for controlled displacement design. In this study plain strain numerical analysis is performed using Plaxis dynamic program where prescribed displacement is applied at the bottom boundary of the soil to simulate the applied seismic load. Constrained absorbent side boundaries are introduced to prevent any wave reflection. The studied soil is chosen dense granular sand and modeled as elasto-plastic material according to Mohr–Column criteria while the gravity wall is assumed elastic. By comparing the resulted seismic wall displacements calculated by numerical analysis for six historical ground motions with that calculated by the pseudo-static method, it is found that numerical seismic displacements are either equal to or greater than corresponding pseudo-static values. Permissible seismic wall displacement calculated by AASHTO can be used for empirical estimation of seismic displacement. It is also found that seismic wall displacement is directly proportional with the positive angle of inclination of the back surface of the wall, soil flexibility and with the earthquake maximum ground acceleration. Seismic wall sliding is dominant and rotation is negligible for rigid walls when the ratio between the wall height and the foundation width is less than 1.4, while for greater ratios the wall becomes more flexible and rotation (rocking increases till the ratio reaches 1.8 where overturning is susceptible to take place. Cumulative seismic wall rotation increases with dynamic time and tends to be constant at the end of earthquake.

  15. A finite state model for respiratory motion analysis in image guided radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wu Huanmei [College of Computer and Information Science, Northeastern University, Boston, MA 02115 (United States); Sharp, Gregory C [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States); Salzberg, Betty [College of Computer and Information Science, Northeastern University, Boston, MA 02115 (United States); Kaeli, David [Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115 (United States); Shirato, Hiroki [Department of Radiation Medicine, Hokkaido University School of Medicine, Sapporo (Japan); Jiang, Steve B [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States)

    2004-12-07

    Effective image guided radiation treatment of a moving tumour requires adequate information on respiratory motion characteristics. For margin expansion, beam tracking and respiratory gating, the tumour motion must be quantified for pretreatment planning and monitored on-line. We propose a finite state model for respiratory motion analysis that captures our natural understanding of breathing stages. In this model, a regular breathing cycle is represented by three line segments, exhale, end-of-exhale and inhale, while abnormal breathing is represented by an irregular breathing state. In addition, we describe an on-line implementation of this model in one dimension. We found this model can accurately characterize a wide variety of patient breathing patterns. This model was used to describe the respiratory motion for 23 patients with peak-to-peak motion greater than 7 mm. The average root mean square error over all patients was less than 1 mm and no patient has an error worse than 1.5 mm. Our model provides a convenient tool to quantify respiratory motion characteristics, such as patterns of frequency changes and amplitude changes, and can be applied to internal or external motion, including internal tumour position, abdominal surface, diaphragm, spirometry and other surrogates.

  16. Optimizing 4-Dimensional Magnetic Resonance Imaging Data Sampling for Respiratory Motion Analysis of Pancreatic Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Stemkens, Bjorn, E-mail: b.stemkens@umcutrecht.nl [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands); Tijssen, Rob H.N. [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands); Senneville, Baudouin D. de [Imaging Division, University Medical Center Utrecht, Utrecht (Netherlands); L' Institut de Mathématiques de Bordeaux, Unité Mixte de Recherche 5251, Centre National de la Recherche Scientifique/University of Bordeaux, Bordeaux (France); Heerkens, Hanne D.; Vulpen, Marco van; Lagendijk, Jan J.W.; Berg, Cornelis A.T. van den [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands)

    2015-03-01

    Purpose: To determine the optimum sampling strategy for retrospective reconstruction of 4-dimensional (4D) MR data for nonrigid motion characterization of tumor and organs at risk for radiation therapy purposes. Methods and Materials: For optimization, we compared 2 surrogate signals (external respiratory bellows and internal MRI navigators) and 2 MR sampling strategies (Cartesian and radial) in terms of image quality and robustness. Using the optimized protocol, 6 pancreatic cancer patients were scanned to calculate the 4D motion. Region of interest analysis was performed to characterize the respiratory-induced motion of the tumor and organs at risk simultaneously. Results: The MRI navigator was found to be a more reliable surrogate for pancreatic motion than the respiratory bellows signal. Radial sampling is most benign for undersampling artifacts and intraview motion. Motion characterization revealed interorgan and interpatient variation, as well as heterogeneity within the tumor. Conclusions: A robust 4D-MRI method, based on clinically available protocols, is presented and successfully applied to characterize the abdominal motion in a small number of pancreatic cancer patients.

  17. Motion analysis systems as optimization training tools in combat sports and martial arts

    Directory of Open Access Journals (Sweden)

    Ewa Polak

    2016-01-01

    Full Text Available Introduction: Over the past years, a few review papers about possibilities of using motion analysis systems in sport were published, but there are no articles that discuss this problem in the field of combat sports and martial arts. Aim: This study presents the diversity of contemporary motion analysis systems both, those that are used in scientific research, as well as those that can be applied in daily work of coaches and athletes in combat sports and martial arts. An additional aim is the indication of example applications in scientific research and range of applications in optimizing the training process. It presents a brief description of each type of systems that are currently used in sport, specific examples of systems and the main advantages and disadvantages of using them. The presentation and discussion takes place in the following sections: motion analysis utility for combat sports and martial arts, systems using digital video and systems using markers, sensors or transmitters. Conclusions: Not all types of motion analysis systems used in sport are suitable for combat sports and martial arts. Scientific studies conducted so far showed the usefulness of video-based, optical and electromechanical systems. The use of research results made with complex motion analysis systems, or made with simple systems, local application and immediate visualization is important for the preparation of training and its optimization. It may lead to technical and tactical improvement in athletes as well as the prevention of injuries in combat sports and martial arts.

  18. Ground motion issues for seismic analysis of tall buildings: A status report

    Science.gov (United States)

    Bozorgnia, Y.; Campbell, K.W.; Luco, N.; Moehle, J.P.; Naeim, F.; Somerville, P.; Yang, T.Y.

    2007-01-01

    The Pacific Earthquake Engineering Research Center (PEER) is coordinating a major multidisciplinary programme, the Tall Buildings Initiative (TBI), to address critical technical issues related to the design and analysis of new tall buildings located in coastal California. The authors of this paper, listed alphabetically, are involved in various research studies related to ground motion modelling, selection, modification and simulation for analysis of tall buildings. This paper summarizes the scope and progress of ongoing activities related to ground motion issues for response history analysis of tall buildings.

  19. Analysis of wall-function approaches using two-equation turbulence models

    Energy Technology Data Exchange (ETDEWEB)

    Albets-Chico, X.; Perez-Segarra, C.D.; Oliva, A. [Centre Tecnologic de Transferencia de Calor, Universitat Politecnica de Catalunya (UPC), ETSEIAT, C/ Colom, 11, 08222 Terrassa (Barcelona) (Spain); Bredberg, J. [Multi-physics/CFD Epsilon, HighTech AB Lindholmspiren 9, SE-41756 Gothenburg (Sweden)

    2008-09-15

    This paper focuses the attention on the drawbacks and abilities of wall-function techniques through an analysis of well-known wall-functions from literature. Besides this, some deeper analysis of these tools by means of physical and numerical considerations are carried out in order to improve their limitations when they are applied to predict heat transfer and fluid flow. Accuracy, grid-sensitivity, numerical behaviour and verification of numerical simulations are key aspects in this paper. The main purpose is to obtain tools which are able to predict both fluid flow and heat transfer with low CPU time consumption, reduced grid-sensitivity and a relatively good accuracy. (author)

  20. Correcting waveform bias using principal component analysis: Applications in multicentre motion analysis studies.

    Science.gov (United States)

    Clouthier, Allison L; Bohm, Eric R; Rudan, John F; Shay, Barbara L; Rainbow, Michael J; Deluzio, Kevin J

    2017-01-01

    Multicentre studies are rare in three dimensional motion analyses due to challenges associated with combining waveform data from different centres. Principal component analysis (PCA) is a statistical technique that can be used to quantify variability in waveform data and identify group differences. A correction technique based on PCA is proposed that can be used in post processing to remove nuisance variation introduced by the differences between centres. Using this technique, the waveform bias that exists between the two datasets is corrected such that the means agree. No information is lost in the individual datasets, but the overall variability in the combined data is reduced. The correction is demonstrated on gait kinematics with synthesized crosstalk and on gait data from knee arthroplasty patients collected in two centres. The induced crosstalk was successfully removed from the knee joint angle data. In the second example, the removal of the nuisance variation due to the multicentre data collection allowed significant differences in implant type to be identified. This PCA-based technique can be used to correct for differences between waveform datasets in post processing and has the potential to enable multicentre motion analysis studies.

  1. Asymptotic analysis of a pile-up of regular edge dislocation walls

    KAUST Repository

    Hall, Cameron L.

    2011-12-01

    The idealised problem of a pile-up of regular dislocation walls (that is, of planes each containing an infinite number of parallel, identical and equally spaced dislocations) was presented by Roy et al. [A. Roy, R.H.J. Peerlings, M.G.D. Geers, Y. Kasyanyuk, Materials Science and Engineering A 486 (2008) 653-661] as a prototype for understanding the importance of discrete dislocation interactions in dislocation-based plasticity models. They noted that analytic solutions for the dislocation wall density are available for a pile-up of regular screw dislocation walls, but that numerical methods seem to be necessary for investigating regular edge dislocation walls. In this paper, we use the techniques of discrete-to-continuum asymptotic analysis to obtain a detailed description of a pile-up of regular edge dislocation walls. To leading order, we find that the dislocation wall density is governed by a simple differential equation and that boundary layers are present at both ends of the pile-up. © 2011 Elsevier B.V.

  2. Physiologically corrected coupled motion during gait analysis using a model-based approach.

    Science.gov (United States)

    Bonnechère, Bruno; Sholukha, Victor; Salvia, Patrick; Rooze, Marcel; Van Sint Jan, Serge

    2015-01-01

    Gait analysis is used in daily clinics for patients' evaluation and follow-up. Stereophotogrammetric devices are the most used tool to perform these analyses. Although these devices are accurate results must be analyzed carefully due to relatively poor reproducibility. One of the major issues is related to skin displacement artifacts. Motion representation is recognized reliable for the main plane of motion displacement, but secondary motions, or combined, are less reliable because of the above artifacts. Model-based approach (MBA) combining accurate joint kinematics and motion data was previously developed based on a double-step registration method. This study presents an extensive validation of this MBA method by comparing results with a conventional motion representation model. Thirty five healthy subjects participated to this study. Gait motion data were obtained from a stereophotogrammetric system. Plug-in Gait model (PiG) and MBA were applied to raw data, results were then compared. Range-of-motion, were computed for pelvis, hip, knee and ankle joints. Differences between PiG and MBA were then computed. Paired-sample t-tests were used to compare both methods. Normalized root-mean square errors were also computed. Shapes of the curves were compared using coefficient of multiple correlations. The MBA and PiG approaches shows similar results for the main plane of motion displacement but statistically significative discrepancies appear for the combined motions. MBA appear to be usable in applications (such as musculoskeletal modeling) requesting better approximations of the joints-of-interest thanks to the integration of validated joint mechanisms.

  3. Singularity and workspace analysis of three isoconstrained parallel manipulators with schoenflies motion

    Science.gov (United States)

    Lee, Po-Chih; Lee, Jyh-Jone

    2012-06-01

    This paper presents the analysis of three parallel manipulators with Schoenflies-motion. Each parallel manipulator possesses two limbs in structure and the end-effector has three DOFs (degree of freedom) in the translational motion and one DOF in rotational motion about a given direction axis with respect to the world coordinate system. The three isoconstrained parallel manipulators have the structures denoted as C{u/u}UwHw-//-C{v/v}UwHw, CuR{u/u}Uhw-//-CvR{v/v}Uhw and CuPuUhw-//-CvPvUhw. The kinematic equations are first introduced for each manipulator. Then, Jacobian matrix, singularity, workspace, and performance index for each mechanism are subsequently derived and analysed for the first time. The results can be helpful for the engineers to evaluate such kind of parallel robots for possible application in industry where pick-and-place motion is required.

  4. Penetrating a Wall of Introspection: A Critical Attrition Analysis

    Science.gov (United States)

    Johannsen, Bjorn Friis; Rump, Camilla Osterberg; Linder, Cedric

    2013-01-01

    This paper presents a critical analysis of student discourse on attrition as it unfolds in interviews on early departure from higher education. A synthesis of relevant studies and modelling done in the field shows that essential aspects affecting attrition and retention can be effectively conceptualized and acted upon in terms of the interplay…

  5. Large scale track analysis for wide area motion imagery surveillance

    Science.gov (United States)

    van Leeuwen, C. J.; van Huis, J. R.; Baan, J.

    2016-10-01

    Wide Area Motion Imagery (WAMI) enables image based surveillance of areas that can cover multiple square kilometers. Interpreting and analyzing information from such sources, becomes increasingly time consuming as more data is added from newly developed methods for information extraction. Captured from a moving Unmanned Aerial Vehicle (UAV), the high-resolution images allow detection and tracking of moving vehicles, but this is a highly challenging task. By using a chain of computer vision detectors and machine learning techniques, we are capable of producing high quality track information of more than 40 thousand vehicles per five minutes. When faced with such a vast number of vehicular tracks, it is useful for analysts to be able to quickly query information based on region of interest, color, maneuvers or other high-level types of information, to gain insight and find relevant activities in the flood of information. In this paper we propose a set of tools, combined in a graphical user interface, which allows data analysts to survey vehicles in a large observed area. In order to retrieve (parts of) images from the high-resolution data, we developed a multi-scale tile-based video file format that allows to quickly obtain only a part, or a sub-sampling of the original high resolution image. By storing tiles of a still image according to a predefined order, we can quickly retrieve a particular region of the image at any relevant scale, by skipping to the correct frames and reconstructing the image. Location based queries allow a user to select tracks around a particular region of interest such as landmark, building or street. By using an integrated search engine, users can quickly select tracks that are in the vicinity of locations of interest. Another time-reducing method when searching for a particular vehicle, is to filter on color or color intensity. Automatic maneuver detection adds information to the tracks that can be used to find vehicles based on their

  6. Motion coordination and performance analysis of multiple vehicle systems

    Science.gov (United States)

    Sharma, Vikrant

    In this dissertation, issues related to multiple vehicle systems are studied. First, the issue of vehicular congestion is addressed and its effect on the performance of some systems studied. Motion coordination algorithms for some systems of interest are also developed. The issue of vehicular congestion is addressed by characterizing the effect of increasing the number of vehicles, in a bounded region, on the speed of the vehicles. A multiple vehicle routing problem is considered where vehicles are required to stay velocity-dependent distance away from each other to avoid physical collisions. Optimal solutions to the minimum time routing are characterized and are found to increase with the square root of the number of vehicles in the environment, for different distributions of the sources and destinations of the vehicles. The second issue addressed is that of the effect of vehicular congestion on the delay associated with data delivery in wireless networks where vehicles are used to transport data to increase the wireless capacity of the network. Tight bounds on the associated delay are derived. The next problem addressed is that of covering an arbitrary path-connected two dimensional region, using multiple unmanned aerial vehicles, in minimum time. A constant-factor optimal algorithm is presented for any given initial positions of the vehicles inside the environment. The last problem addressed is that of the deployment of an environment monitoring network of mobile sensors to improve the network lifetime and sensing quality. A distributed algorithm is presented that improves the system's performance starting from an initial deployment.

  7. Effect of Electric Field and Temperature on Average Structure and Domain Wall Motion in 0.93Bi0.5Na0.5TiO3-0.07BaTiO3 Ceramic

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2013-01-01

    Full Text Available In situ neutron powder diffraction patterns and dielectric spectra of 0.93Bi0.5Na0.5TiO3-0.07BaTiO3 ceramic were investigated under different electrical fields and temperatures. An electric-field-induced phase transition from metrically cubic to metrically tetragonal, associated with strong domain wall motion, occurs. Such induced phase and domain wall motion are unchanged until the high-temperature phase transition occurs from metrically tetragonal to metrically cubic. All these changes are irrelevant to the observed depolarization temperature (75°C. The depolarization behaviour is thus suggested to be associated with the local structure caused by the octahedral tilt twinning disorder.

  8. Numerical Analysis of Composite Steel Concrete Structural Shear Walls with Steel Encased Profiles

    Directory of Open Access Journals (Sweden)

    Daniel Dan

    2009-01-01

    Full Text Available The use of common reinforced concrete shear walls in high rise buildings is sometimes limited because of the large amount of reinforcement localized at the end of the element. A good alternative in avoiding this disadvantage is to use composite steel concrete structural shear walls with steel encased profiles. This solution used for high rise buildings, offers to designers lateral stiffness, shear capacity and high bending resisting moment of structural walls. The encasement of the steel shapes in concrete is applied also for the following purposes: flexural stiffening and strengthening of compression elements; fire protection; potentially easier repairs after moderate damage; economy with respect both to material and construction. Until now in the national and international literature poor information about nonlinear behaviour of composite steel concrete structural shear walls with steel encased profiles is available. A theoretical and experimental program related to the behaviour of steel concrete structural shear walls with steel encased profiles is developed at “Politehnica” University of Timişoara. The program refers to six different elements, which differ by the shape of the steel encased profile and also by the arrangement of steel shapes on the cross section of the element. In order to calibrate the elements for experimental study some numerical analysis were made. The paper presents the results of numerical analysis with details of stress distribution, crack distribution, structural stiffness at various loads, and load bearing capacity of the elements.

  9. Non-Linear Static Analysis of G+6 Storeyed RC Buildings with Openings in Infill Walls

    Directory of Open Access Journals (Sweden)

    Praveen Rathod

    2014-09-01

    Full Text Available Masonry infill walls are commonly used in the RC frame structure buildings. Openings are inevitable part of the infill walls. Openings in infill walls significantly decrease the lateral strength and stiffness of RC frames. In the present study two-dimensional seven storeyed reinforced concrete (RC building models are considered with of (5%, 25%, and 35% openings Bare frame and soft storey buildings are modeled considering special moment resisting frame (SMRF for medium soil profile and zone III. Concrete block infill walls are modeled as pin-jointed single equivalent diagonal strut. Pushover analysis is carried out for both default and user defined hinge properties as per FEMA 440 guidelines using SAP2000 software. Results of default and user defined hinge properties are studied by pushover analysis. The results of ductility ratio, safety ratio, global stiffness, and hinge status at performance point are compared with the models. Authors conclude that as the percentage of openings increases, vulnerability increases in the infill walls. The user-defined hinge model is better than the default-hinge model in reflecting nonlinear behavior. The misuse of default-hinge properties may lead to unreasonable displacement capacities for existing structures. However, if the default-hinge model is preferred due to simplicity, the user should be aware of what is provided in the program and should avoid the misuse of default-hinge properties.

  10. Interpretation of scrape-off layer profile evolution and first-wall ion flux statistics on JET using a stochastic framework based on fillamentary motion

    Science.gov (United States)

    Walkden, N. R.; Wynn, A.; Militello, F.; Lipschultz, B.; Matthews, G.; Guillemaut, C.; Harrison, J.; Moulton, D.; Contributors, JET

    2017-08-01

    This paper presents the use of a novel modelling technique based around intermittent transport due to filament motion, to interpret experimental profile and fluctuation data in the scrape-off layer (SOL) of JET during the onset and evolution of a density profile shoulder. A baseline case is established, prior to shoulder formation, and the stochastic model is shown to be capable of simultaneously matching the time averaged profile measurement as well as the PDF shape and autocorrelation function from the ion-saturation current time series at the outer wall. Aspects of the stochastic model are then varied with the aim of producing a profile shoulder with statistical measurements consistent with experiment. This is achieved through a strong localised reduction in the density sink acting on the filaments within the model. The required reduction of the density sink occurs over a highly localised region with the timescale of the density sink increased by a factor of 25. This alone is found to be insufficient to model the expansion and flattening of the shoulder region as the density increases, which requires additional changes within the stochastic model. An example is found which includes both a reduction in the density sink and filament acceleration and provides a consistent match to the experimental data as the shoulder expands, though the uniqueness of this solution can not be guaranteed. Within the context of the stochastic model, this implies that the localised reduction in the density sink can trigger shoulder formation, but additional physics is required to explain the subsequent evolution of the profile.

  11. Interventricular delay measurement using equilibrium radionuclide angiography before resynchronization therapy should be performed outside the area of segmental wall motion abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Courtehoux, Maxime [Service EFMP CHU Trousseau, Chambray les Tours (France); Zannad, Noura; Fauchier, Laurent; Babuty, Dominique [Service Cardiologie B CHU Trousseau, Tours (France); Eder, Veronique [Service EFMP CHU Trousseau, Chambray les Tours (France); EA3852 University Francois Rabelais, Tours (France)

    2011-02-15

    The aim of this study was to demonstrate that only mechanical dyssynchrony outside the area of segmental wall motion abnormalities (WMA) can be reduced by cardiac resynchronization therapy (CRT). Included in the study were 28 consecutive patients with nonischaemic cardiomyopathy selected for CRT. Equilibrium radionuclide angiography (ERNA) was carried out before and after implantation of a multisite pacemaker. Patients were separated into two groups depending on the presence or absence of segmental WMA. A reduction in QRS duration was observed in all patients after CRT. The interventricular delay (IVD) decreased significantly after CRT only in patients without WMA (homogeneous contraction, HG group; IVD 44 {+-} 11.4 vs. 17 {+-} 3.1 , p = 0.04). In contrast, no significant decrease was observed in patients with WMA (WMA group; IVD 51 {+-} 6 vs. 38 {+-} 6 , p NS). However, when dyssynchrony was considered outside the WMA area, a significant reduction in IVD was obtained, in the same range as in the HG group (IVD 32 {+-} 3 vs. 19 {+-} 3 , p = 0.04). In 9 of 15 patients (60%) with a reduction in IVD after CRT, the left ventricle ejection fraction (LVEF) increased by about +10%. In contrast, in 13 of 13 patients (100%) with no reduction in IVD, no modification of LVEF was obtained. In the presence of segmental WMA without significant delays outside the WMA area, no reduction in IVD was observed and LVEF did not increase (IVD 34 {+-} 5 before CRT vs. 37 {+-} 7 after CRT; LVEF 19 {+-} 4% before CRT vs. 22 {+-} 3% after CRT, p NS). ERNA can be used to predict good mechanical resynchronization (decrease in IVD) in patients after pacing. IVD has to be determined excluding the area of WMA in order to select patients who will show an increase in their left ventricle function after CRT. (orig.)

  12. DEFINITION AND ANALYSIS OF MOTION ACTIVITY AFTER-STROKE PATIENT FROM THE VIDEO STREAM

    Directory of Open Access Journals (Sweden)

    M. Yu. Katayev

    2014-01-01

    Full Text Available This article describes an approach to the assessment of motion activity of man in after-stroke period, allowing the doctor to get new information to give a more informed recommendations on rehabilitation treatment than in traditional approaches. Consider description of the hardware-software complex for determination and analysis of motion activity after-stroke patient for the video stream. The article provides a description of the complex, its algorithmic filling and the results of the work on the example of processing of the actual data. The algorithms and technology to significantly accelerate the gait analysis and improve the quality of diagnostics post-stroke patients.

  13. Dynamics analysis of planar armored cable motion in deep-sea ROV system

    Institute of Scientific and Technical Information of China (English)

    全伟才; 张竺英; 张艾群

    2014-01-01

    The armored cable used in a deep-sea remotely operated vehicle (ROV) may undergo large displacement motion when subjected to dynamic actions of ship heave motion and ocean current. A novel geometrically exact finite element model for two-dimensional dynamic analysis of armored cable is presented. This model accounts for the geometric nonlinearities of large displacement of the armored cable, and effects of axial load and bending stiffness. The governing equations are derived by consistent linearization and finite element discretization of the total weak form of the armored cable system, and solved by the Newmark time integration method. To make the solution procedure avoid falling into the local extreme points, a simple adaptive stepping strategy is proposed. The presented model is validated via actual measured data. Results for dynamic configurations, motion and tension of both ends of the armored cable, and resonance-zone are presented for two numerical cases, including the dynamic analysis under the case of only ship heave motion and the case of joint action of ship heave motion and ocean current. The dynamics analysis can provide important reference for the design or product selection of the armored cable in a deep-sea ROV system so as to improve the safety of its marine operation under the sea state of 4 or above.

  14. Using the Front Page of "The Wall Street Journal" to Teach Document Design and Audience Analysis.

    Science.gov (United States)

    Moore, Patrick

    1989-01-01

    Explains an assignment for the audience analysis segment of a business writing course which compares the front page design of "The Wall Street Journal" with that of a local daily newspaper in order to emphasize the use of design devices in effectively writing to busy people. (SR)

  15. Using the Front Page of "The Wall Street Journal" to Teach Document Design and Audience Analysis.

    Science.gov (United States)

    Moore, Patrick

    1989-01-01

    Explains an assignment for the audience analysis segment of a business writing course which compares the front page design of "The Wall Street Journal" with that of a local daily newspaper in order to emphasize the use of design devices in effectively writing to busy people. (SR)

  16. Computationally efficient analysis and optimisation of stiffened thin-walled panels in shear

    CSIR Research Space (South Africa)

    Viljoen, A

    2005-05-01

    Full Text Available nonlinear finite element analysis, which makes it attractive for use during initial design iterations, even though global collapse of a structure cannot be predicted. As an illustration of the optimal design of buckled, stiffened thin-walled structures...

  17. Application of Reliability Analysis for Optimal Design of Monolithic Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard; Christiani, E.

    1995-01-01

    Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of some of the most important failure modes are described. The failures are sliding and slip surface failure of a rubble mound and a clay foundation. Relevant design...... variables are identified and a reliability-based design optimization procedure is formulated. Results from an illustrative example are given....

  18. Numerical Analysis of Dynamic Force Acting Perpendicularly on a Wall Made of Concrete Blocks with Rubber Inserts

    Directory of Open Access Journals (Sweden)

    Major Maciej

    2016-12-01

    Full Text Available In this paper numerical analysis considering the influence of dynamical force acting on wall made of concrete blocks with rubber inserts is presented. By examining the stress values on front and back surface of the analysed wall structure model, the effectiveness of proposed solution can be measured comparing to the wall made of concrete blocks without rubber inserts. Complete numerical analysis was performed in ADINA program.

  19. Robust object tracking techniques for vision-based 3D motion analysis applications

    Science.gov (United States)

    Knyaz, Vladimir A.; Zheltov, Sergey Y.; Vishnyakov, Boris V.

    2016-04-01

    Automated and accurate spatial motion capturing of an object is necessary for a wide variety of applications including industry and science, virtual reality and movie, medicine and sports. For the most part of applications a reliability and an accuracy of the data obtained as well as convenience for a user are the main characteristics defining the quality of the motion capture system. Among the existing systems for 3D data acquisition, based on different physical principles (accelerometry, magnetometry, time-of-flight, vision-based), optical motion capture systems have a set of advantages such as high speed of acquisition, potential for high accuracy and automation based on advanced image processing algorithms. For vision-based motion capture accurate and robust object features detecting and tracking through the video sequence are the key elements along with a level of automation of capturing process. So for providing high accuracy of obtained spatial data the developed vision-based motion capture system "Mosca" is based on photogrammetric principles of 3D measurements and supports high speed image acquisition in synchronized mode. It includes from 2 to 4 technical vision cameras for capturing video sequences of object motion. The original camera calibration and external orientation procedures provide the basis for high accuracy of 3D measurements. A set of algorithms as for detecting, identifying and tracking of similar targets, so for marker-less object motion capture is developed and tested. The results of algorithms' evaluation show high robustness and high reliability for various motion analysis tasks in technical and biomechanics applications.

  20. Particle Motion Analysis Reveals Nanoscale Bond Characteristics and Enhances Dynamic Range for Biosensing.

    Science.gov (United States)

    Visser, Emiel W A; van IJzendoorn, Leo J; Prins, Menno W J

    2016-03-22

    Biofunctionalized colloidal particles are widely used as labels in bioanalytical assays, lab-on-chip devices, biophysical research, and in studies on live biological systems. With detection resolution going down to the level of single particles and single molecules, understanding the nature of the interaction of the particles with surfaces and substrates becomes of paramount importance. Here, we present a comprehensive study of motion patterns of colloidal particles maintained in close proximity to a substrate by short molecular tethers (40 nm). The motion of the particles (500-1000 nm) was optically tracked with a very high localization accuracy (below 3 nm). A surprisingly large variation in motion patterns was observed, which can be attributed to properties of the particle-molecule-substrate system, namely the bond number, the nature of the bond, particle protrusions, and substrate nonuniformities. Experimentally observed motion patterns were compared to numerical Monte Carlo simulations, revealing a close correspondence between the observed motion patterns and properties of the molecular system. Particles bound via single tethers show distinct disc-, ring-, and bell-shaped motion patterns, where the ring- and bell-shaped patterns are caused by protrusions on the particle in the direct vicinity of the molecular attachment point. Double and triple tethered particles exhibit stripe-shaped and triangular-shaped motion patterns, respectively. The developed motion pattern analysis allows for discrimination between particles bound by different bond types, which opens the possibility to improve the limit of detection and the dynamic range of bioanalytical assays, with a projected increase of dynamic range by nearly 2 orders of magnitude.

  1. ANALYSIS OF A RIGID WALL IN AN ELASTIC WEIGHTY HALF-PLANE

    Directory of Open Access Journals (Sweden)

    K. V. Dmitrieva

    2016-01-01

    Full Text Available The analysis of stress-strain state of a rigid wall in an elastic weighty half-plane with a broken outline is carried out. To this end, the auxiliary problem of displacements definition in an elastic weighty quarter-plane was solved. Ritz method derived a formula to determine the displacements of elastic flat wedge boundaries in view of its own weight. On the basis of the received expressions the algorithm of displacements definition of a crack in an elastic weighty half-plane with a broken outline is developed. Analytical calculation of a rigid vertical wall located in an elastic weighty half-plane under the influence of a horizontal load, carried out by two methods: by Zhemochkin's method and finite difference method. In the problem statement an elastic half-plane is considered a model of the soil medium, therefore, only compressive normal stresses can arise on the connection of the wall with the elastic base. This assumption implies occurrence of discontinuities soil medium, and leads for the wall to an emergence of two dividing points of boundary conditions. The determination of the boundaries contact of the wall with the elastic half-plane, are not known in advance, is performed by iteratively way at each step set the position of dividing points of boundary conditions and the system of canonical equations of a corresponding method is written.  If tensile stresses appear in wall-base contact and/or there is overlap of the crack edges occurs, then proceeds to the next iteration. Analysis of the results shows that the bending moment and shear forces in sections of the rigid wall in a broken weighty half-plane differ slightly from the same diagrams constructed for a rigid wall in an elastic weightless half-plane. The verification of the results of analytical calculation with the results received by using the LIRA 9.6 that implements the finite element method is obtained. The calculation results for the rigid wall in an elastic weighty half

  2. AMAB: Automated measurement and analysis of body motion

    NARCIS (Netherlands)

    Poppe, Ronald; Zee, van der Sophie; Heylen, Dirk K.J.; Taylor, Paul J.

    2014-01-01

    Technologies that measure human nonverbal behavior have existed for some time, and their use in the analysis of social behavior has become more popular following the development of sensor technologies that record full-body movement. However, a standardized methodology to efficiently represent and an

  3. AMAB: Automated measurement and analysis of body motion

    NARCIS (Netherlands)

    Poppe, Ronald Walter; van der Zee, Sophie; Heylen, Dirk K.J.; Taylor, Paul J; Taylor, Paul J.

    Technologies that measure human nonverbal behavior have existed for some time, and their use in the analysis of social behavior has become more popular following the development of sensor technologies that record full-body movement. However, a standardized methodology to efficiently represent and

  4. Motion analysis of knee joint using dynamic volume images

    Science.gov (United States)

    Haneishi, Hideaki; Kohno, Takahiro; Suzuki, Masahiko; Moriya, Hideshige; Mori, Sin-ichiro; Endo, Masahiro

    2006-03-01

    Acquisition and analysis of three-dimensional movement of knee joint is desired in orthopedic surgery. We have developed two methods to obtain dynamic volume images of knee joint. One is a 2D/3D registration method combining a bi-plane dynamic X-ray fluoroscopy and a static three-dimensional CT, the other is a method using so-called 4D-CT that uses a cone-beam and a wide 2D detector. In this paper, we present two analyses of knee joint movement obtained by these methods: (1) transition of the nearest points between femur and tibia (2) principal component analysis (PCA) of six parameters representing the three dimensional movement of knee. As a preprocessing for the analysis, at first the femur and tibia regions are extracted from volume data at each time frame and then the registration of the tibia between different frames by an affine transformation consisting of rotation and translation are performed. The same transformation is applied femur as well. Using those image data, the movement of femur relative to tibia can be analyzed. Six movement parameters of femur consisting of three translation parameters and three rotation parameters are obtained from those images. In the analysis (1), axis of each bone is first found and then the flexion angle of the knee joint is calculated. For each flexion angle, the minimum distance between femur and tibia and the location giving the minimum distance are found in both lateral condyle and medial condyle. As a result, it was observed that the movement of lateral condyle is larger than medial condyle. In the analysis (2), it was found that the movement of the knee can be represented by the first three principal components with precision of 99.58% and those three components seem to strongly relate to three major movements of femur in the knee bend known in orthopedic surgery.

  5. VIDEO OBJECT SEGMENTATION BY 2-D MESH-BASED MOTION ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Video object extraction is a key technology in content-based video coding. A novel video object extracting algorithm by two Dimensional (2-D) mesh-based motion analysis is proposed in this paper. Firstly, a 2-D mesh fitting the original frame image is obtained via feature detection algorithm.Then, higher order statistics motion analysis is applied on the 2-D mesh representation to get an initial motion detection mask. After post-processing, the final segmenting mask is quickly obtained. And hence the video object is effectively extracted. Experimental results show that the proposed algorithm combines the merits of mesh-based segmenting algorithms and pixel-based segmenting algorithms, and hereby achieves satisfactory subjective and objective performance while dramatically increasing the segmenting speed.

  6. A novel system of four-dimensional motion analysis after total hip arthroplasty.

    Science.gov (United States)

    Hagio, Keisuke; Sugano, Nobuhiko; Nishii, Takashi; Miki, Hidenobu; Otake, Yoshito; Hattori, Asaki; Suzuki, Naoki; Yonenobu, Kazuo; Yoshikawa, Hideki; Ochi, Takahiro

    2004-05-01

    We have developed a novel system of four-dimensional motion analysis after total hip arthroplasty (THA) that can aid in preventing dislocation by assessing safe range of motion for patients in several daily activities. This system uses skeletal structure data from CT and motion capture data from an infrared position sensor. A 3-D model reconstructed from CT data is combined with the motion capture data. Using this system, we analyzed hip motion when getting up from and sitting down in a chair or picking up an object while sitting in a chair in 17 patients (26 hips) who underwent THA. To assess the accuracy of this system's measurements, open MRI was used to evaluate positions of skin markers against bones in five healthy volunteers in various postures. No impingement between bones and/or implants was found in any subjects during any activities. However, mean angle at the point of maximum hip flexion was different for each patient. The open MRI results indicated that average error in hip angle of the present system was within 5 degrees for each static posture. The functional position of the pelvis during daily activities must be taken into account when assessing the real risk of dislocation. The present system enables dynamic analysis involving not only alignment of components and bones of each patient, but also individual differences in characteristics of daily motions. Further investigation using this system can help determine safe ranges of motion for preventing hip dislocation, improving the accuracy of individualized guidance for patients regarding postoperative activities.

  7. Spectroscopic Analysis of Wall Conditioning Methods in NSTX

    Science.gov (United States)

    Forbes, Eleanor; Soukhanovskii, Vlad

    2015-11-01

    Plasma confinement and performance in NSTX are reliant upon well-conditioned plasma facing components (PFCs). Past conditioning techniques used in NSTX include hot and cold boronization, lithium pellet injection (LPI), and lithium evaporation. The influx of hydrogen-containing molecules and radicals can be studied through spectroscopic observation of the hydrogen to deuterium (H/D) intensity ratio in the edge plasma. A code to determine H/D ratios has been developed and tested on known light sources before being applied to data from prior NSTX experiments. In general, boronization was found to reduce the H/D ratio, with further H reduction seen from cold boronization when compared to hot boronization. No correlation between LPI and H/D ratio was observed. Lithium evaporation produced a significant H decrease. In the future this analysis will be applied immediately following NSTX-U pulses to provide data on plasma-surface interactions. This work was made possible by funding from the Department of Energy for the Summer Undergraduate Laboratory Internship (SULI) program. This work is supported by the US DOE Contract No.DE-AC02-09CH11466 and DE-AC52-07NA27344.

  8. Performance analysis of greenhouse dryer by using insulated north-wall under natural convection mode

    Directory of Open Access Journals (Sweden)

    Prashant Singh Chauhan

    2016-11-01

    Full Text Available A prototype north wall insulated greenhouse dryer has been fabricated and tested in no-load conditions under natural convection mode. Experimentation has been conducted in two different cases. Case-I is when solar collector placed inside the dryer and Case-II is North wall insulated greenhouse dryer without solar collector. Coefficient of performance, heat utilisation factor, convective heat transfer coefficient and coefficient of diffusivity have been evaluated in thermal performance analysis. The difference of the highest convective heat transfer coefficient of both cases is 29.094W/m2°C which is showing the effectiveness of insulated north wall and solar collector. The maximum coefficient of diffusivity (0.0827 was achieved during the third day of experiment in Case-II. The inside room temperature of wall insulated greenhouse dryer for Case-I is 4.11%, 5.08 % and 11.61 % higher than the Case-II during the day 1, day 2 and day 3 respectively. This result is also showing the effectiveness of solar collector and insulated north wall. The highest heat utilisation factor (0.616 is obtained during the second day for Case-I while for Case-II it is 0.769 during the third day of experimentation. Maximum coefficient of performance achieved is 0.892 during the third day of the experiment for Case-I whereas 0.953 is obtained on the first day of experimentation for Case-II.

  9. A Zonal Similarity Analysis of Velocity Profiles in Wall-Bounded Turbulent Shear Flows

    CERN Document Server

    Tuoc, Trinh Khanh

    2010-01-01

    It is argued that there are three distinct zones in a wall bounded turbulent flow field dominated by three completely different mechanisms: - An outer region where the velocity profile is determined by the pressure distribution - A highly active wall layer dominated by a sequence of inrush-sweep and ejections, and - An intermediate region well described by the traditional logarithmic law proposed by independently Millikan and Prandtl. The log-law and the wall layer are sometimes referred to as the inner region. Under these conditions, a unique set of normalisation parameters cannot possibly apply to all three zones. The inner region can be more successfully represented by normalising the distance and velocity with the values of these scales at the edge of the wall layer since they are shared by both the wall layer and the log-law region. The application of this similarity analysis has successfully collapsed extensive published data for the inner region covering a range of Reynolds numbers from 3000 to 1,000,0...

  10. A HYBRID SYSTEM FOR DYNAMIC ANALYSIS AND DESIGN OF COUPLED SHEAR WALLS

    Directory of Open Access Journals (Sweden)

    A BERRAIS

    2000-06-01

    Full Text Available Non-linear dynamic analysis techniques are rapidly being developed and have been recognized as indispensable tools. However, their use in the design office requires special experience. Consequently they are not generally accepted as analysis/design tools. Additionally, uncertainties are associated with the determination of the earthquake forces, the stiffness and strength of the structure; the selection of the mathematical models; and the form of the earthquake. In this paper a hybrid system for the non-linear dynamic analysis/design of coupled shear walls is briefly described. The system combines expert system technology with finite element method to carry out the dynamic analysis of coupled walls under earthquake forces. The system has been implemented using Quintec-Prolog, Quintec-Flex and FORTRAN 77, and runs on a SUN SPARC station under Unix system.

  11. Wearable inertial sensors in swimming motion analysis: a systematic review.

    Science.gov (United States)

    de Magalhaes, Fabricio Anicio; Vannozzi, Giuseppe; Gatta, Giorgio; Fantozzi, Silvia

    2015-01-01

    The use of contemporary technology is widely recognised as a key tool for enhancing competitive performance in swimming. Video analysis is traditionally used by coaches to acquire reliable biomechanical data about swimming performance; however, this approach requires a huge computational effort, thus introducing a delay in providing quantitative information. Inertial and magnetic sensors, including accelerometers, gyroscopes and magnetometers, have been recently introduced to assess the biomechanics of swimming performance. Research in this field has attracted a great deal of interest in the last decade due to the gradual improvement of the performance of sensors and the decreasing cost of miniaturised wearable devices. With the aim of describing the state of the art of current developments in this area, a systematic review of the existing methods was performed using the following databases: PubMed, ISI Web of Knowledge, IEEE Xplore, Google Scholar, Scopus and Science Direct. Twenty-seven articles published in indexed journals and conference proceedings, focusing on the biomechanical analysis of swimming by means of inertial sensors were reviewed. The articles were categorised according to sensor's specification, anatomical sites where the sensors were attached, experimental design and applications for the analysis of swimming performance. Results indicate that inertial sensors are reliable tools for swimming biomechanical analyses.

  12. Dynamic Analysis of Flanged Shear Wall Using Staad

    Directory of Open Access Journals (Sweden)

    Pro T. Subramani

    2014-06-01

    Full Text Available Earthquakes demonstrate vulnerability of various inadequate structures, every time they occur. The lessons taught from the aftermath of earthquakes and the research works being carried out in laboratories give better understanding about the performance of the structure and their components. Damage in reinforced concrete structures was mainly attributed to the inadequate detailing of reinforcement, lack of transverse steel and confinement of concrete in structural elements. Typical failures were brittle in nature, demonstrating inadequate capacity to dissipate and absorb inelastic energy. This necessitates a better understanding of the design and detailing of the reinforced concrete structures under various types of loading. An extensive description of previous studies on the underlying theory and the application of the finite element method to the linear and nonlinear analysis of reinforced concrete structures is presented in excellent state of-the-art reports by the American Society of Civil Engineers in 1982 [ASCE 1982]. The results from the FEA are significantly relied on the stress-strain relationship of the materials, failure criteria chosen, simulation of the crack of concrete and the interaction of the reinforcement and concrete.Because of these complexity in short- and long-term behavior of the constituent materials, the ANSYS finite element program introduces a three-dimensional element Solid65 which is capable of cracking and crushing and is then combined along with models of the interaction between the two constituents to describe the behavior of the composite reinforced concrete material. Although the Solid 65 can describe the reinforcing bars, this study uses an additional element, Link8, to investigate the stress along the reinforcement because it is inconvenient to collect the smear rebar data from Solid 65.

  13. Numerical analysis of heat transfer in the first wall of CFETR WCSB blanket

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Pinghui, E-mail: phzhao@mail.ustc.edu.cn; Deng, Weiping; Ge, Zhihao; Li, Yuanjie

    2016-04-15

    Highlights: • Detailed numerical analysis of heat transfer in a water-cooling first wall was carried out based on the conceptual design of CFETR WCSB blanket. • Investigation of the influences of buoyancy effect and surface roughness on heat transfer in the water-cooling first wall was presented. • Analysis of the effect of the front wall thickness on temperature was carried out for the water-cooling first wall design. • Simulation results of two 1D CFD methods were evaluated by the 3D CFD data. - Abstract: China Fusion Engineering Test Reactor (CFETR), the first fusion reactor experiment project planned in China, is now being investigated in detail. Recently, a conceptual structural design of the Water-Cooled-Solid-Breeder (WCSB) blanket was proposed as one of the breeding blanket candidates for CFETR. In this research, based on the present design of the CFETR WCSB blanket, the heat transfer performance in the first wall (FW) under the pressurized water cooling condition was analyzed. The 3D computational fluid dynamics (CFD) results show that the maximal temperature of the FW will not exceed the limited temperature under normal or even higher heat flux condition. In addition, the effect of buoyancy on heat transfer is negligible under both conditions. The influence of roughness becomes increasingly important when the roughness height lies in the fully turbulent regime. The maximal temperature increases approximately linearly as the thickness of the front wall increases. It is also found that the heat flux and the local heat transfer coefficient are extremely non-uniform in the circumferential direction. Two 1D CFD methods are also evaluated by 3D CFD data, with the conclusion that both 1D results have some differences with the 3D data. The improved 1D method is more accurate than the former one. However, we ascertain that 1D methods should be used with caution for the water-cooling FW design.

  14. Robust motion tracking based on adaptive speckle decorrelation analysis of OCT signal.

    Science.gov (United States)

    Wang, Yuewen; Wang, Yahui; Akansu, Ali; Belfield, Kevin D; Hubbi, Basil; Liu, Xuan

    2015-11-01

    Speckle decorrelation analysis of optical coherence tomography (OCT) signal has been used in motion tracking. In our previous study, we demonstrated that cross-correlation coefficient (XCC) between Ascans had an explicit functional dependency on the magnitude of lateral displacement (δx). In this study, we evaluated the sensitivity of speckle motion tracking using the derivative of function XCC(δx) on variable δx. We demonstrated the magnitude of the derivative can be maximized. In other words, the sensitivity of OCT speckle tracking can be optimized by using signals with appropriate amount of decorrelation for XCC calculation. Based on this finding, we developed an adaptive speckle decorrelation analysis strategy to achieve motion tracking with optimized sensitivity. Briefly, we used subsequently acquired Ascans and Ascans obtained with larger time intervals to obtain multiple values of XCC and chose the XCC value that maximized motion tracking sensitivity for displacement calculation. Instantaneous motion speed can be calculated by dividing the obtained displacement with time interval between Ascans involved in XCC calculation. We implemented the above-described algorithm in real-time using graphic processing unit (GPU) and demonstrated its effectiveness in reconstructing distortion-free OCT images using data obtained from a manually scanned OCT probe. The adaptive speckle tracking method was validated in manually scanned OCT imaging, on phantom as well as in vivo skin tissue.

  15. ANALYSIS OF THE MOTION OF AN EXTRASOLAR PLANET IN A BINARY SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Plávalová, Eva [Astronomical Institute, Slovak Academy of Science, Bratislava (Slovakia); Solovaya, Nina A., E-mail: plavala@slovanet.sk, E-mail: solov@sai.msu.ru [Sternberg State Astronomical Institute, Lomonosov Moscow State University, Moscow (Russian Federation)

    2013-11-01

    More than 10% of extra-solar planets (EPs) orbit in a binary or multiple stellar system. We investigated the motion of planets revolving in binary systems in the case of the three-body problem. We carried out an analysis of the motion of an EP revolving in a binary system with the following conditions: (1) a planet in a binary system revolves around one of the components (parent star); (2) the distance between the star's components is greater than that between the parent star and the orbiting planet (ratio of the semi-major axes is a small parameter); and (3) the mass of the planet is smaller than the mass of the stars, but is not negligible. The Hamiltonian of the system without short periodic terms was used. We expanded the Hamiltonian in terms of the Legendre polynomial and truncated after the second-order term, depending on only one angular variable. In this case, the solution of the system was obtained and the qualitative analysis of the motion was produced. We have applied this theory to real EPs and compared to the numerical integration. Analyses of the possible regions of motion are presented. It is shown that stable and unstable motions of EPs are possible. We applied our calculations to two binary systems hosting an EP and calculated the possible values for their unknown orbital elements.

  16. The adaptation of GDL motion recognition system to sport and rehabilitation techniques analysis.

    Science.gov (United States)

    Hachaj, Tomasz; Ogiela, Marek R

    2016-06-01

    The main novelty of this paper is presenting the adaptation of Gesture Description Language (GDL) methodology to sport and rehabilitation data analysis and classification. In this paper we showed that Lua language can be successfully used for adaptation of the GDL classifier to those tasks. The newly applied scripting language allows easily extension and integration of classifier with other software technologies and applications. The obtained execution speed allows using the methodology in the real-time motion capture data processing where capturing frequency differs from 100 Hz to even 500 Hz depending on number of features or classes to be calculated and recognized. Due to this fact the proposed methodology can be used to the high-end motion capture system. We anticipate that using novel, efficient and effective method will highly help both sport trainers and physiotherapist in they practice. The proposed approach can be directly applied to motion capture data kinematics analysis (evaluation of motion without regard to the forces that cause that motion). The ability to apply pattern recognition methods for GDL description can be utilized in virtual reality environment and used for sport training or rehabilitation treatment.

  17. 75 FR 39203 - Notice of Availability of a Pest Risk Analysis for Importation of Wall Rocket Leaves from the...

    Science.gov (United States)

    2010-07-08

    ... Animal and Plant Health Inspection Service Notice of Availability of a Pest Risk Analysis for Importation... prepared a pest risk analysis with respect to perennial wall rocket leaves grown in the United Kingdom. The... plant pests or noxious weeds via the importation of wall rocket leaves from the United Kingdom. We...

  18. Actigraphy and motion analysis: new tools for psychiatry.

    Science.gov (United States)

    Teicher, M H

    1995-01-01

    Altered locomotor activity is a cardinal sign of several psychiatric disorders. With advances in technology, activity can now be measured precisely. Contemporary studies quantifying activity in psychiatric patients are reviewed. Studies were located by a Medline search (1965 to present; English language only) cross-referencing motor activity and major psychiatric disorders. The review focused on mood disorders and attention-deficit hyperactivity disorder (ADHD). Activity levels are elevated in mania, agitated depression, and ADHD and attenuated in bipolar depression and seasonal depression. The percentage of low-level daytime activity is directly related to severity of depression, and change in this parameter accurately mirrors recovery. Demanding cognitive tasks elicit fidgeting in children with ADHD, and precise measures of activity and attention may provide a sensitive and specific marker for this disorder. Circadian rhythm analysis enhances the sophistication of activity measures. Affective disorders in children and adolescents are characterized by an attenuated circadian rhythm and an enhanced 12-hour harmonic rhythm (diurnal variation). Circadian analysis may help to distinguish between the activity patterns of mania (dysregulated) and ADHD (intact or enhanced). Persistence of hyperactivity or circadian dysregulation in bipolar patients treated with lithium appears to predict rapid relapse once medication is discontinued. Activity monitoring is a valuable research tool, with the potential to aid clinicians in diagnosis and in prediction of treatment response.

  19. Cultural meanings of nature: an analysis of contemporary motion pictures.

    Science.gov (United States)

    Pollio, Howard R; Anderson, John; Levasseur, Priscilla; Thweatt, Michael

    2003-03-01

    To evaluate current cultural meanings of nature, the authors asked 65 undergraduate students to "list 3 movies in which nature was an important aspect of the film." They also were asked to specify the natural element that stood out to them and describe "how it related to the overall theme of the movie." Two independent groups of raters skilled in interpretive analysis developed thematic meanings from these responses. Following this, in a 2nd study, a different group of participants rated the 18 most frequently mentioned natural elements on thematic scales derived from the initial interpretive analysis. Participants in the 1st study mentioned 33 different movies at least twice and 5 themes that captured the meaning of nature in these films. Correlational results derived from the 2nd study indicated that rating scales reflecting these 5 themes formed 2 distinct groups; the first group described settings in which nature is experienced as adversarial and plays a significant role in dramatic action, and the second group defined settings in which nature is viewed either as a place of refuge or simply as a locale in which ongoing narrative action occurs. The general conclusion reached in both studies concerns the often noted but not always appreciated fact that movies--similar to everyday events and actions--always take place in specific settings and that neither life events nor dramatic narratives can be understood apart from specific settings.

  20. SMART USE OF COMPUTER-AIDED SPERM ANALYSIS (CASA) TO CHARACTERIZE SPERM MOTION

    Science.gov (United States)

    Computer-aided sperm analysis (CASA) has evolved over the past fifteen years to provide an objective, practical means of measuring and characterizing the velocity and parttern of sperm motion. CASA instruments use video frame-grabber boards to capture multiple images of spermato...

  1. Ultrasonic motion analysis system - measurement of temporal and spatial gait parameters

    NARCIS (Netherlands)

    Huitema, RB; Hof, AL; Postema, K

    2002-01-01

    The duration of stance and swing phase and step and stride length are important parameters in human gait. In this technical note a low-cost ultrasonic motion analysis system is described that is capable of measuring these temporal and spatial parameters while subjects walk on the floor. By using the

  2. SMART USE OF COMPUTER-AIDED SPERM ANALYSIS (CASA) TO CHARACTERIZE SPERM MOTION

    Science.gov (United States)

    Computer-aided sperm analysis (CASA) has evolved over the past fifteen years to provide an objective, practical means of measuring and characterizing the velocity and parttern of sperm motion. CASA instruments use video frame-grabber boards to capture multiple images of spermato...

  3. The Accuracy of Screw Axis Analysis Using Position Data from Anatomical Motion Studies.

    Science.gov (United States)

    1980-05-05

    Hip Motion ........ . 57 7-2 Screw Axis Analysis for the Sacro -iliac Joint. 57 viii " LIST OF FIGURES Figure Title Page 2-1 Systems Anthropometry Data...The piercing point selected for this test was an arbitrary point. The screw axis direction was selected so that there would be equal components in all...analyzed are the hip, and the sacro -iliac joint. The bone movements analyzed are the femur moving relative to the left inominate for hip motion, and the

  4. Motion analysis of waste rock in gas-solids fluidized bed in coal dry beneficiation

    Institute of Scientific and Technical Information of China (English)

    郭迎福; 陈安华; 张永忠; 邓志鹏; 毛树楷

    2002-01-01

    Through the analysis of forces acting on the waste rock in the gas-solid fluidized bed, the waste rock velocity equations and displacement equations in the gas-solids fluidized bed were achieved and the influential factors of the waste rock motion in the fluidized bed were studied in this paper. The conclusions show that the primary factors influencing the waste rock motion are the waste rock grain size and the scraper velocity according to the computer simulation. This has provided the theoretical foundation both for improving the separating effect and ascertaining the length of the separating cell.

  5. Piping benchmark problems. Volume 1. Dynamic analysis uniform support motion response spectrum method

    Energy Technology Data Exchange (ETDEWEB)

    Bezler, P.; Hartzman, M.; Reich, M.

    1980-08-01

    A set of benchmark problems and solutions have been developed for verifying the adequacy of computer programs used for dynamic analysis and design of nuclear piping systems by the Response Spectrum Method. The problems range from simple to complex configurations which are assumed to experience linear elastic behavior. The dynamic loading is represented by uniform support motion, assumed to be induced by seismic excitation in three spatial directions. The solutions consist of frequencies, participation factors, nodal displacement components and internal force and moment components. Solutions to associated anchor point motion static problems are not included.

  6. Computation Analysis of Buckling Loads of Thin-Walled Members with Open Sections

    Directory of Open Access Journals (Sweden)

    Lihua Huang

    2016-01-01

    Full Text Available The computational methods for solving buckling loads of thin-walled members with open sections are not unique when different concerns are emphasized. In this paper, the buckling loads of thin-walled members in linear-elastic, geometrically nonlinear-elastic, and nonlinear-inelastic behaviors are investigated from the views of mathematical formulation, experiment, and numerical solution. The differential equations and their solutions of linear-elastic and geometrically nonlinear-elastic buckling of thin-walled members with various constraints are derived. Taking structural angle as an example, numerical analysis of elastic and inelastic buckling is carried out via ANSYS. Elastic analyses for linearized buckling and nonlinear buckling are realized using finite elements of beam and shell and are compared with the theoretical results. The effect of modeling of constraints on numerical results is studied when shell element is applied. The factors that influence the inelastic buckling load in numerical solution, such as modeling of constraint, loading pattern, adding rib, scale factor of initial defect, and yield strength of material, are studied. The noteworthy problems and their solutions in numerically buckling analysis of thin-walled member with open section are pointed out.

  7. In situ analysis of cell wall polymers associated with phloem fibre cells in stems of hemp, Cannabis sativa L.

    Science.gov (United States)

    Blake, Anthony W; Marcus, Susan E; Copeland, James E; Blackburn, Richard S; Knox, J Paul

    2008-06-01

    A study of stem anatomy and the sclerenchyma fibre cells associated with the phloem tissues of hemp (Cannabis sativa L.) plants is of interest for both understanding the formation of secondary cell walls and for the enhancement of fibre utility as industrial fibres and textiles. Using a range of molecular probes for cell wall polysaccharides we have surveyed the presence of cell wall components in stems of hemp in conjunction with an anatomical survey of stem and phloem fibre development. The only polysaccharide detected to occur abundantly throughout the secondary cell walls of phloem fibres was cellulose. Pectic homogalacturonan epitopes were detected in the primary cell walls/intercellular matrices between the phloem fibres although these epitopes were present at a lower level than in the surrounding parenchyma cell walls. Arabinogalactan-protein glycan epitopes displayed a diversity of occurrence in relation to fibre development and the JIM14 epitope was specific to fibre cells, binding to the inner surface of secondary cell walls, throughout development. Xylan epitopes were found to be present in the fibre cells (and xylem secondary cell walls) and absent from adjacent parenchyma cell walls. Analysis of xylan occurrence in the phloem fibre cells of hemp and flax indicated that xylan epitopes were restricted to the primary cell walls of fibre cells and were not present in the secondary cell walls of these cells.

  8. Developments in target micro-Doppler signatures analysis: radar imaging, ultrasound and through-the-wall radar

    Science.gov (United States)

    Clemente, Carmine; Balleri, Alessio; Woodbridge, Karl; Soraghan, John J.

    2013-12-01

    Target motions, other than the main bulk translation of the target, induce Doppler modulations around the main Doppler shift that form what is commonly called a target micro-Doppler signature. Radar micro-Doppler signatures are generally both target and action specific and hence can be used to classify and recognise targets as well as to identify possible threats. In recent years, research into the use of micro-Doppler signatures for target classification to address many defence and security challenges has been of increasing interest. In this article, we present a review of the work published in the last 10 years on emerging applications of radar target analysis using micro-Doppler signatures. Specifically we review micro-Doppler target signatures in bistatic SAR and ISAR, through-the-wall radar and ultrasound radar. This article has been compiled to provide radar practitioners with a unique reference source covering the latest developments in micro-Doppler analysis, extraction and mitigation techniques. The article shows that this research area is highly active and fast moving and demonstrates that micro-Doppler techniques can provide important solutions to many radar target classification challenges.

  9. Texture analysis improves level set segmentation of the anterior abdominal wall

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhoubing [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 (United States); Allen, Wade M. [Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States); Baucom, Rebeccah B.; Poulose, Benjamin K. [General Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37235 (United States); Landman, Bennett A. [Electrical Engineering, Vanderbilt University, Nashville, Tennessee 37235 and Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)

    2013-12-15

    Purpose: The treatment of ventral hernias (VH) has been a challenging problem for medical care. Repair of these hernias is fraught with failure; recurrence rates ranging from 24% to 43% have been reported, even with the use of biocompatible mesh. Currently, computed tomography (CT) is used to guide intervention through expert, but qualitative, clinical judgments, notably, quantitative metrics based on image-processing are not used. The authors propose that image segmentation methods to capture the three-dimensional structure of the abdominal wall and its abnormalities will provide a foundation on which to measure geometric properties of hernias and surrounding tissues and, therefore, to optimize intervention.Methods: In this study with 20 clinically acquired CT scans on postoperative patients, the authors demonstrated a novel approach to geometric classification of the abdominal. The authors’ approach uses a texture analysis based on Gabor filters to extract feature vectors and follows a fuzzy c-means clustering method to estimate voxelwise probability memberships for eight clusters. The memberships estimated from the texture analysis are helpful to identify anatomical structures with inhomogeneous intensities. The membership was used to guide the level set evolution, as well as to derive an initial start close to the abdominal wall.Results: Segmentation results on abdominal walls were both quantitatively and qualitatively validated with surface errors based on manually labeled ground truth. Using texture, mean surface errors for the outer surface of the abdominal wall were less than 2 mm, with 91% of the outer surface less than 5 mm away from the manual tracings; errors were significantly greater (2–5 mm) for methods that did not use the texture.Conclusions: The authors’ approach establishes a baseline for characterizing the abdominal wall for improving VH care. Inherent texture patterns in CT scans are helpful to the tissue classification, and texture

  10. Design and analysis of optimal multi-layer walls for time-varying thermal excitation

    Science.gov (United States)

    Bond, Danielle E. M.

    U.S. buildings are a significant source of energy consumption (about 50%) and carbon emissions (about 40%), and providing conditioning to building interiors is a major portion of that expenditure. Improving building envelope performance can reduce the amount of energy used for heating and cooling, since external walls provide an important barrier between occupied building spaces and variable ambient conditions. In general, multi-layer exterior walls tend to perform better than single-layer walls, even for the same overall R-value and thermal capacitance. This work addresses practical choices in multi-layer wall design to minimize internal temperature swings that result from outside, or ambient, temperature fluctuations. An electrical analogy is used to model one-dimensional heat conduction using RC circuits. A frequency response analysis is conducted based on a period of one day. For a fixed wall thickness, four features are optimized: materials, proportion of materials, number of layers, and material distribution. Key design features include pairing insulating and thermally massive materials, distributing layers evenly, and positioning the insulating layers at the inner- and outer-most layers of the wall (i.e., near the indoor and outdoor environments). Methods for determining the optimal proportion of each material and number of layers are also presented. Combined, these easily implemented features can reduce interior temperature fluctuations by several orders of magnitude compared to ambient temperature variations. This helps maintain steady indoor temperatures, which is more comfortable for building occupants, and supports energy management strategies, like reducing peak heating and cooling loads.

  11. Analysis of the Accuracy and Robustness of the Leap Motion Controller

    Directory of Open Access Journals (Sweden)

    Denis Fisseler

    2013-05-01

    Full Text Available The Leap Motion Controller is a new device for hand gesture controlled user interfaces with declared sub-millimeter accuracy. However, up to this point its capabilities in real environments have not been analyzed. Therefore, this paper presents a first study of a Leap Motion Controller. The main focus of attention is on the evaluation of the accuracy and repeatability. For an appropriate evaluation, a novel experimental setup was developed making use of an industrial robot with a reference pen allowing a position accuracy of 0.2 mm. Thereby, a deviation between a desired 3D position and the average measured positions below 0.2mmhas been obtained for static setups and of 1.2mmfor dynamic setups. Using the conclusion of this analysis can improve the development of applications for the Leap Motion controller in the field of Human-Computer Interaction.

  12. Mass asymmetry and tricyclic wobble motion assessment using automated launch video analysis

    Institute of Scientific and Technical Information of China (English)

    Ryan DECKER; Joseph DONINI; William GARDNER; Jobin JOHN; Walter KOENIG

    2016-01-01

    This paper describes an approach to identify epicyclic and tricyclic motion during projectile flight caused by mass asymmetries in spin-stabilized projectiles. Flight video was captured following projectile launch of several M110A2E1 155 mm artillery projectiles. These videos were then analyzed using the automated flight video analysis method to attain their initial position and orientation histories. Examination of the pitch and yaw histories clearly indicates that in addition to epicyclic motion’s nutation and precession oscillations, an even faster wobble amplitude is present during each spin revolution, even though some of the amplitudes of the oscillation are smaller than 0.02 degree. The results are compared to a sequence of shots where little appreciable mass asymmetries were present, and only nutation and precession frequencies are predominantly apparent in the motion history results. Magnitudes of the wobble motion are estimated and compared to product of inertia measurements of the asymmetric projectiles.

  13. Analysis of the accuracy and robustness of the leap motion controller.

    Science.gov (United States)

    Weichert, Frank; Bachmann, Daniel; Rudak, Bartholomäus; Fisseler, Denis

    2013-05-14

    The Leap Motion Controller is a new device for hand gesture controlled user interfaces with declared sub-millimeter accuracy. However, up to this point its capabilities in real environments have not been analyzed. Therefore, this paper presents a first study of a Leap Motion Controller. The main focus of attention is on the evaluation of the accuracy and repeatability. For an appropriate evaluation, a novel experimental setup was developed making use of an industrial robot with a reference pen allowing a position accuracy of 0.2 mm. Thereby, a deviation between a desired 3D position and the average measured positions below 0.2 mm has been obtained for static setups and of 1.2 mm for dynamic setups. Using the conclusion of this analysis can improve the development of applications for the Leap Motion controller in the field of Human-Computer Interaction.

  14. A time motion analysis of bouldering style competitive rock climbing.

    Science.gov (United States)

    White, Dominic J; Olsen, Peter D

    2010-05-01

    Limited research has been performed on competitive bouldering. The aim of this study was to quantify the movement dynamics of elite boulder climbers. Six climbers were filmed during a national competition consisting of 5 novel climbing problems or routes. Two problems were randomly selected and film footage was analyzed using Kandle Swinger Pro software to determine type and duration (seconds) of bouldering movements. All subjects provided consent, and the study had ethical approval. The mean +/- SD were determined for number of attempts per problem, duration of attempt, time on hold, and time to reach between holds. Exercise:recovery ratios were also calculated. On average, climbers attempted a problem 3.0 +/- 0.5 times, with an attempt lasting 28.9 +/- 10.8 seconds and rest periods of 114 +/- 31 seconds between attempts. Average time gripping holds was 7.9 +/- 1.3 seconds, with approximately 0.5 +/- 0.1 seconds recovery between reaching for holds. The exercise-to-recovery ratio was approximately 1:4 for attempting a problem and approximately 13:1 for forearm muscles during climbing. The exercise-to-recovery ratios allow sufficient time for recovery during and after a problem. However, the prolonged contraction of forearm muscles indicates the importance of strength and endurance in these muscles. Video analysis was found to be a useful tool for the quantification of movement characteristics of competitive elite boulders. Data collected could be utilized in the design of sport-specific tests and training programs. Future research could examine a larger number of athletes and problems and help develop performance tests and training interventions for bouldering.

  15. Seismic fragility analysis of a CANDU containment structure for near-fault ground motions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, In Kil; Choun, Young Sun; Seo, Jeong Moon; Ahn, Seong Moon [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2005-07-01

    The R. G. 1.60 spectrum used for the seismic design of Korean nuclear power plants provides a generally conservative design basis due to its broadband nature. A survey on some of the Quaternary fault segments near Korean nuclear power plants is ongoing. It is likely that these faults will be identified as active ones. If the faults are confirmed as active ones, it will be necessary to reevaluate the seismic safety of the nuclear power plants located near these faults. The probability based scenario earthquakes were identified as near-field earthquakes. In general, the near-fault ground motion records exhibit a distinctive long period pulse like time history with very high peak velocities. These features are induced by the slip of the earthquake fault. Near-fault ground motions, which have caused much of the damage in recent major earthquakes, can be characterized by a pulse-like motion that exposes the structure to a high input energy at the beginning of the motion. It is necessary to estimate the near-fault ground motion effects on the nuclear power plant structures and components located near the faults. In this study, the seismic fragility analysis of a CANDU containment structure was performed based on the results of nonlinear dynamic time-history analyses.

  16. Analysis of tissue changes, measurement system effects, and motion artifacts in echo decorrelation imaging.

    Science.gov (United States)

    Hooi, Fong Ming; Nagle, Anna; Subramanian, Swetha; Douglas Mast, T

    2015-02-01

    Echo decorrelation imaging, a method for mapping ablation-induced ultrasound echo changes, is analyzed. Local echo decorrelation is shown to approximate the decoherence spectrum of tissue reflectivity. Effects of the ultrasound measurement system, echo signal windowing, electronic noise, and tissue motion on echo decorrelation images are determined theoretically, leading to a method for reduction of motion and noise artifacts. Theoretical analysis is validated by simulations and experiments. Simulated decoherence of the scattering medium was recovered with root-mean-square error less than 10% with accuracy dependent on the correlation window size. Motion-induced decorrelation measured in an ex vivo pubovisceral muscle model showed similar trends to theoretical motion-induced decorrelation for a 2.1 MHz curvilinear array with decorrelation approaching unity for 3-4 mm elevational displacement or 1-1.6 mm range displacement. For in vivo imaging of porcine liver by a 7 MHz linear array, theoretical decorrelation computed using image-based motion estimates correlated significantly with measured decorrelation (r = 0.931, N = 10). Echo decorrelation artifacts incurred during in vivo radiofrequency ablation in the same porcine liver were effectively compensated based on the theoretical echo decorrelation model and measured pre-treatment decorrelation. These results demonstrate the potential of echo decorrelation imaging for quantification of heat-induced changes to the scattering tissue medium during thermal ablation.

  17. Bifurcation analysis and stability design for aircraft longitudinal motion with high angle of attack

    Institute of Scientific and Technical Information of China (English)

    Xin Qi; Shi Zhongke

    2015-01-01

    Bifurcation analysis and stability design for aircraft longitudinal motion are investigated when the nonlinearity in flight dynamics takes place severely at high angle of attack regime. To pre-dict the special nonlinear flight phenomena, bifurcation theory and continuation method are employed to systematically analyze the nonlinear motions. With the refinement of the flight dynam-ics for F-8 Crusader longitudinal motion, a framework is derived to identify the stationary bifurca-tion and dynamic bifurcation for high-dimensional system. Case study shows that the F-8 longitudinal motion undergoes saddle node bifurcation, Hopf bifurcation, Zero-Hopf bifurcation and branch point bifurcation under certain conditions. Moreover, the Hopf bifurcation renders ser-ies of multiple frequency pitch oscillation phenomena, which deteriorate the flight control stability severely. To relieve the adverse effects of these phenomena, a stabilization control based on gain scheduling and polynomial fitting for F-8 longitudinal motion is presented to enlarge the flight envelope. Simulation results validate the effectiveness of the proposed scheme.

  18. Comparison of wall thickening and perfusion analysis in cardiomyopathy by gated Tc-99m MIBI

    Energy Technology Data Exchange (ETDEWEB)

    Cho, I.; Chun, K.; Won, K.; Lee, H.; Park, J.; Shin, D.; Kim, Y.; Shim, B [Yeungnam University Hospital, Taegu (Korea, Republic of)

    2002-07-01

    The objective of this study was to clarify the relationship between left ventriculr (LV) function, wall thickening (WT) and perfusion in cardiomyopathy. Twenty-six cases (15 males, 11 females: mean age, 58 y), consisting of 10 healthy control subjects, 10 patients with hypertrophic cardiomyopathy (HCM) and 6 patients with idiopathic dilated cardiomyopathy (DCM) was studied with gated Tc-99m MIBI SPECT. LV WT, LV perfusion and function (LV wall motion, LVEDV, LVESV and LVEF) by using gated SPECT quantification and CEqual software were analysed. In HCM and DCM group, mean WT was significantly decreased. (HCM: 15.2{+-}6.7%, DCM: 4.9%, control: 34.1{+-}4.9% (p<0.01). Adenosine stress test didn't show any reversible or fixed perfusion defects in all HCM patients, controls and five DCM patients except one patient (but, no coronary artery stenosis in coronary angiography). LVEF for HCM, DCM and control was 48.4{+-}13.2%, 28.7{+-}8.8%, 62.7{+-}9.5%, respectively (p<0.05)). LVEDV and LVESV didn't show a significant differences between HCM and control group, not DCM group. In HCM, WT was decreased as like DCM even though LV myocardial perfusion and function was reserved.

  19. Reliability and Validity of Quantitative Video Analysis of Baseball Pitching Motion.

    Science.gov (United States)

    Oyama, Sakiko; Sosa, Araceli; Campbell, Rebekah; Correa, Alexandra

    2017-02-01

    Video recordings are used to quantitatively analyze pitchers' techniques. However, reliability and validity of such analysis is unknown. The purpose of the study was to investigate the reliability and validity of joint and segment angles identified during a pitching motion using video analysis. Thirty high school baseball pitchers participated. The pitching motion was captured using 2 high-speed video cameras and a motion capture system. Two raters reviewed the videos to digitize the body segments to calculate 2-dimensional angles. The corresponding 3-dimensional angles were calculated from the motion capture data. Intrarater reliability, interrater reliability, and validity of the 2-dimensional angles were determined. The intrarater and interrater reliability of the 2-dimensional angles were high for most variables. The trunk contralateral flexion at maximum external rotation was the only variable with high validity. Trunk contralateral flexion at ball release, trunk forward flexion at foot contact and ball release, shoulder elevation angle at foot contact, and maximum shoulder external rotation had moderate validity. Two-dimensional angles at the shoulder, elbow, and trunk could be measured with high reliability. However, the angles are not necessarily anatomically correct, and thus use of quantitative video analysis should be limited to angles that can be measured with good validity.

  20. Energy Consumption Analysis Procedure for Robotic Applications in different task motion

    Science.gov (United States)

    Ahmed, Iman; Aris, Ishak b.; Hamiruce Marhaban, Mohammad; Juraiza Ishak, Asnor

    2015-11-01

    This work proposes energy analysis method for humanoid robot, seen from simple motion task to complex one in energy chain. The research developed a procedure suitable for analysis, saving and modelling of energy consumption not only in this type of robot but also in most robots that based on electrical power as an energy source. This method has validated by an accurate integration using Matlab software for the power consumption curve to calculate the energy of individual and multiple servo motors. Therefore, this study can be considered as a procedure for energy analysis by utilizing the laboratory instruments capabilities to measure the energy parameters. We performed a various task motions with different angular speed to find out the speed limits in terms of robot stability and control strategy. A battery capacity investigation have been searched for several types of batteries to extract the power modelling equation and energy density parameter for each battery type, Matlab software have been built to design the algorithm and to evaluate experimental amount of the energy which is represented by area under the curve of the power curves. This will provide a robust estimation for the required energy in different task motions to be considered in energy saving (i.e., motion planning and real time scheduling).

  1. Structural Analysis Approach to Fault Diagnosis with Application to Fixed-wing Aircraft Motion

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh

    2001-01-01

    The paper presents a structural analysis based method for fault diagnosis purposes. The method uses the structural model of the system and utilizes the matching idea to extract system's inherent redundant information. The structural model is represented by a bipartite directed graph. FDI Possibil...... Possibilities are examined by further analysis of the obtained information. The method is illustrated by applying on the LTI model of motion of a fixed-wing aircraft....

  2. Structural Analysis Approach to Fault Diagnosis with Application to Fixed-wing Aircraft Motion

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh

    2002-01-01

    The paper presents a structural analysis based method for fault diagnosis purposes. The method uses the structural model of the system and utilizes the matching idea to extract system's inherent redundant information. The structural model is represented by a bipartite directed graph. FDI Possibil...... Possibilities are examined by further analysis of the obtained information. The method is illustrated by applying on the LTI model of motion of a fixed-wing aircraft....

  3. Structural Analysis Approach to Fault Diagnosis with Application to Fixed-wing Aircraft Motion

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh

    2002-01-01

    The paper presents a structural analysis based method for fault diagnosis purposes. The method uses the structural model of the system and utilizes the matching idea to extract system's inherent redundant information. The structural model is represented by a bipartite directed graph. FDI Possibil...... Possibilities are examined by further analysis of the obtained information. The method is illustrated by applying on the LTI model of motion of a fixed-wing aircraft....

  4. Design and analysis of Stress on Thick Walled Cylinder with and with out Holes

    Directory of Open Access Journals (Sweden)

    G.Raju

    2015-01-01

    Full Text Available The conventional elastic analysis of thick walled cylinders to final radial & hoop stresses is applicable for the internal pressures up to yield strength of material. The stress is directly proportional to strain up to yield point Beyond elastic point, particularly in thick walled cylinders. The operating pressures are reduced or the material properties are strengthened. There is no such existing theory for the stress distributions around radial holes under impact of varying internal pressure. Present work puts thrust on this area and relation between pressure and stress distribution is plotted graphically based on observations. Here focus is on pure mechanical analysis & hence thermal, effects are not considered. The thick walled cylinders with a radial cross-hole ANSYS Macro program employed to evaluate the fatigue life of vessel. Stresses that remain in material even after removing applied loads are known as residual stresses. These stresses occur only when material begins to yield plastically. Residual stresses can be present in any mechanical structure because of many causes. Residual stresses may be due to the technological process used to make the component. Manufacturing processes lead to plastic deformation. Elasto plastic analysis with bilinear kinematic hardening material is performed to know the effect of hole sizes. It is observed that there are several factors which influence stress intensity factors. The Finite element analysis is conducted using commercial solvers ANSYS & CATIA. Theoretical formulae based results are obtained from MATLAB programs. The results are presented in form of graphs and tables.

  5. Asymptotic modal analysis of a rectangular acoustic cavity excited by wall vibration

    Science.gov (United States)

    Peretti, Linda F.; Dowell, Earl H.

    1992-01-01

    Asymptotic modal analysis, a method that has recently been developed for structural dynamical systems, has been applied to a rectangular acoustic cavity. The cavity had a flexible vibrating portion on one wall, and the other five walls were rigid. Banded white noise was transmitted through the flexible portion (plate) only. Both the location along the wall and the size of the plate were varied. The mean square pressure levels of the cavity interior were computed as a ratio of the result obtained from classical modal analysis to that obtained from asymptotic modal analysis for the various plate configurations. In general, this ratio converged to 1.0 as the number of responding modes increased. Intensification effects were found due to both the excitation location and the response location. The asymptotic modal analysis method was both efficient and accurate in solving the given problem. The method has advantages over the traditional methods that are used for solving dynamics problems with a large number of responding modes.

  6. Lunar Return Reentry Thermal Analysis of a Generic Crew Exploration Vehicle Wall Structures

    Science.gov (United States)

    Ko, William L.; Tran, Van T.; Bowles, Jeff

    2007-01-01

    Thermostructural analysis was performed on generic crew exploration vehicle (GCEV) heat shielded wall structures subjected to reentry heating rates based on five potential lunar return reentry trajectories. The GCEV windward outer wall is fabricated with a graphite/epoxy composite honeycomb sandwich panel and the inner wall with an aluminum honeycomb sandwich panel. The outer wall is protected with an ablative Avcoat-5026-39H/CG thermal protection system (TPS). A virtual ablation method (a graphical approximation) developed earlier was further extended, and was used to estimate the ablation periods, ablation heat loads, and the TPS recession layer depths. It was found that up to 83 95 percent of the total reentry heat load was dissipated in the TPS ablation process, leaving a small amount (3-15 percent) of the remaining total reentry heat load to heat the virgin TPS and maintain the TPS surface at the ablation temperature, 1,200 F. The GCEV stagnation point TPS recession layer depths were estimated to be in the range of 0.280-0.910 in, and the allowable minimum stagnation point TPS thicknesses that could maintain the substructural composite sandwich wall at the limit temperature of 300 F were found to be in the range of 0.767-1.538 in. Based on results from the present analyses, the lunar return abort ballistic reentry was found to be quite attractive because it required less TPS weight than the lunar return direct, the lunar return skipping, or the low Earth orbit guided reentry, and only 11.6 percent more TPS weight than the low Earth orbit ballistic reentry that will encounter a considerable weight penalty to obtain the Earth orbit. The analysis also showed that the TPS weight required for the lunar return skipping reentry was much more than the TPS weight necessary for any of the other reentry trajectories considered.

  7. A New Motion Capture System For Automated Gait Analysis Based On Multi Video Sequence Analysis

    DEFF Research Database (Denmark)

    Jensen, Karsten; Juhl, Jens

    There is an increasing demand for assessing foot mal positions and an interest in monitoring the effect of treatment. In the last decades several different motion capture systems has been used. This abstract describes a new low cost motion capture system....

  8. The Structure of Plant Cell Walls: I. The Macromolecular Components of the Walls of Suspension-cultured Sycamore Cells with a Detailed Analysis of the Pectic Polysaccharides.

    Science.gov (United States)

    Talmadge, K W; Keegstra, K; Bauer, W D; Albersheim, P

    1973-01-01

    This is the first in a series of papers dealing with the structure of cell walls isolated from suspension-cultured sycamore cells (Acer pseudoplatanus). These studies have been made possible by the availability of purified hydrolytic enzymes and by recent improvements in the techniques of methylation analysis. These techniques have permitted us to identify and quantitate the macromolecular components of sycamore cell walls. These walls are composed of 10% arabinan, 2% 3,6-linked arabinogalactan, 23% cellulose, 9% oligo-arabinosides (attached to hydroxyproline), 8% 4-linked galactan, 10% hydroxyproline-rich protein, 16% rhamnogalacturonan, and 21% xyloglucan.The structures of the pectic polymers (the neutral arabinan, the neutral galactan, and the acidic rhamnogalacturonan) were obtained, in part, by methylation analysis of fragments of these polymers which were released from the sycamore walls by the action of a highly purified endopolygalacturonase. The data suggest a branched arabinan and a linear 4-linked galactan occurring as side chains on the rhamnogalacturonan. Small amounts or pieces of a xyloglucan, the wall hemicellulose, appear to be covalently linked to some of the galactan chains. Thus, the galactan appears to serve as a bridge between the xyloglucan and rhamnogalacturonan components of the wall.The rhamnogalacturonan consists of an alpha-(1 --> 4)-linked galacturonan chain which is interspersed with 2-linked rhamnosyl residues. The rhamnosyl residues are not randomly distributed in the chain but probably occur in units of rhamnosyl- (1 --> 4)-galacturonosyl- (1 --> 2)-rhamnosyl. This sequence appears to alternate with a homogalacturonan sequence containing approximately 8 residues of 4-linked galacturonic acid. About half of the rhamnosyl residues are branched, having a substituent attached to carbon 4. This is likely to be the site of attachment of the 4-linked galactan.The hydroxyprolyl oligo-arabinosides of the hydroxyproline-rich glycoprotein

  9. Numerical analysis of a PCM thermal storage system with varying wall temperature

    Energy Technology Data Exchange (ETDEWEB)

    Halawa, E. [Sustainable Energy Centre, University of South Australia, Mawson Lakes, SA 5095 (Australia)]. E-mail: edward.halawa@unisa.edu.au; Bruno, F. [Sustainable Energy Centre, University of South Australia, Mawson Lakes, SA 5095 (Australia); Saman, W. [Sustainable Energy Centre, University of South Australia, Mawson Lakes, SA 5095 (Australia)

    2005-09-15

    Numerical analysis of melting and freezing of a PCM thermal storage unit (TSU) with varying wall temperature is presented. The TSU under analysis consists of several layers of thin slabs of a PCM subjected to convective boundary conditions where air flows between the slabs. The model employed takes into account the variations in wall temperature along the direction of air flow as well as the sensible heat. The paper discusses typical characteristics of the melting/freezing of PCM slabs in an air stream and presents some results of the numerical simulation in terms of air outlet temperatures and heat transfer rates during the whole periods of melting and freezing. Considerations in the design of the TSU are also given.

  10. Wall-induced path variation of a large deformable rising bubble

    Science.gov (United States)

    Park, Hyungmin; Jeong, Hyeonju

    2014-11-01

    In the present study, we experimentally investigate the wall-induced path variation of a large deformable bubble (Re ~ O (103)) rising near a vertical wall in quiescent water. To change the wall effect, we consider different wall materials (acrylic, PTFE and sponge) and vary the initial distance between the bubble and the wall. Depending on the conditions, various motions like a periodic bouncing, sliding, migrating away, and non-periodic oscillation without collisions are captured. Analysis on the energy balance shows that, contrary to a low- Re bubble, the surface deformation plays a great role in bubble's rising behaviour. Especially, across the bubble-wall collision, the excessive surface energy compensates the deficit of kinetic energy, which enables the bubble to maintain a constant bouncing kinematics, despite the wall effect. The wall effect, appearing as a energy loss, decreases as the distance to the wall increases. Compared to the no-slip surface, the hydrophobic surface enhances or reduces the wall effect with the wall distance, whereas the porous surface reduces the energy loss due to the wall. The dependence of near-wall bubble motion on a wall configuration may give us an idea about how to predict or model the near-wall gas void-fraction. Supported by the NRF Programs (NRF-2012M2A8A4055647, NRF-2013R1A1A1008373) of Korean government.

  11. Seismic behavior and mechanism analysis of innovative precast shear wall involving vertical joints

    Institute of Scientific and Technical Information of China (English)

    孙建; 邱洪兴

    2015-01-01

    To study the seismic performance and load-transferring mechanism of an innovative precast shear wall (IPSW) involving vertical joints, an experimental investigation and theoretical analysis were successively conducted on two test walls. The test results confirm the feasibility of the novel joints as well as the favorable seismic performance of the walls, even though certain optimization measures should be taken to improve the ductility. The load-transferring mechanism subsequently is theoretically investigated based on the experimental study. The theoretical results show the load-transferring route of the novel joints is concise and definite. During the elastic stage, the vertical shear stress in the connecting steel frame (CSF) distributes uniformly;and each high-strength bolt (HSB) primarily delivers vertical shear force. However, the stress in the CSF redistributes when the walls develop into the elastic-plastic stage. At the ultimate state, the vertical shear stress and horizontal normal stress in the CSF distribute linearly;and the HSBs at both ends of the CSF transfer the maximum shear forces.

  12. Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines

    Directory of Open Access Journals (Sweden)

    Jeffrey Tuck

    2013-12-01

    Full Text Available Analysis of transient fluid pressure signals has been investigated as an alternative method of fault detection in pipeline systems and has shown promise in both laboratory and field trials. The advantage of the method is that it can potentially provide a fast and cost effective means of locating faults such as leaks, blockages and pipeline wall degradation within a pipeline while the system remains fully operational. The only requirement is that high speed pressure sensors are placed in contact with the fluid. Further development of the method requires detailed numerical models and enhanced understanding of transient flow within a pipeline where variations in pipeline condition and geometry occur. One such variation commonly encountered is the degradation or thinning of pipe walls, which can increase the susceptible of a pipeline to leak development. This paper aims to improve transient-based fault detection methods by investigating how changes in pipe wall thickness will affect the transient behaviour of a system; this is done through the analysis of laboratory experiments. The laboratory experiments are carried out on a stainless steel pipeline of constant outside diameter, into which a pipe section of variable wall thickness is inserted. In order to detect the location and severity of these changes in wall conditions within the laboratory system an inverse transient analysis procedure is employed which considers independent variations in wavespeed and diameter. Inverse transient analyses are carried out using a genetic algorithm optimisation routine to match the response from a one-dimensional method of characteristics transient model to the experimental time domain pressure responses. The accuracy of the detection technique is evaluated and benefits associated with various simplifying assumptions and simulation run times are investigated. It is found that for the case investigated, changes in the wavespeed and nominal diameter of the

  13. Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines

    Science.gov (United States)

    Tuck, Jeffrey; Lee, Pedro

    2013-01-01

    Analysis of transient fluid pressure signals has been investigated as an alternative method of fault detection in pipeline systems and has shown promise in both laboratory and field trials. The advantage of the method is that it can potentially provide a fast and cost effective means of locating faults such as leaks, blockages and pipeline wall degradation within a pipeline while the system remains fully operational. The only requirement is that high speed pressure sensors are placed in contact with the fluid. Further development of the method requires detailed numerical models and enhanced understanding of transient flow within a pipeline where variations in pipeline condition and geometry occur. One such variation commonly encountered is the degradation or thinning of pipe walls, which can increase the susceptible of a pipeline to leak development. This paper aims to improve transient-based fault detection methods by investigating how changes in pipe wall thickness will affect the transient behaviour of a system; this is done through the analysis of laboratory experiments. The laboratory experiments are carried out on a stainless steel pipeline of constant outside diameter, into which a pipe section of variable wall thickness is inserted. In order to detect the location and severity of these changes in wall conditions within the laboratory system an inverse transient analysis procedure is employed which considers independent variations in wavespeed and diameter. Inverse transient analyses are carried out using a genetic algorithm optimisation routine to match the response from a one-dimensional method of characteristics transient model to the experimental time domain pressure responses. The accuracy of the detection technique is evaluated and benefits associated with various simplifying assumptions and simulation run times are investigated. It is found that for the case investigated, changes in the wavespeed and nominal diameter of the pipeline are both important

  14. Dynamic motion analysis of dart throwers motion visualized through computerized tomography and calculation of the axis of rotation.

    Science.gov (United States)

    Edirisinghe, Y; Troupis, J M; Patel, M; Smith, J; Crossett, M

    2014-05-01

    We used a dynamic three-dimensional (3D) mapping method to model the wrist in dynamic unrestricted dart throwers motion in three men and four women. With the aid of precision landmark identification, a 3D coordinate system was applied to the distal radius and the movement of the carpus was described. Subsequently, with dynamic 3D reconstructions and freedom to position the camera viewpoint anywhere in space, we observed the motion pathways of all carpal bones in dart throwers motion and calculated its axis of rotation. This was calculated to lie in 27° of anteversion from the coronal plane and 44° of varus angulation relative to the transverse plane. This technique is a safe and a feasible carpal imaging method to gain key information for decision making in future hand surgical and rehabilitative practices.

  15. Rigid body motion analysis system for off-line processing of time-coded video sequences

    Science.gov (United States)

    Snow, Walter L.; Shortis, Mark R.

    1995-09-01

    Photogrammetry affords the only noncontact means of providing unambiguous six-degree-of- freedom estimates for rigid body motion analysis. Video technology enables convenient off- the-shelf capability for obtaining and storing image data at frame (30 Hz) or field (60 Hz) rates. Videometry combines these technologies with frame capture capability accessible to PCs to allow unavailable measurements critical to the study of rigid body dynamics. To effectively utilize this capability, however, some means of editing, post processing, and sorting substantial amounts of time coded video data is required. This paper discusses a prototype motion analysis system built around PC and video disk technology, which is proving useful in exploring applications of these concepts to rigid body tracking and deformation analysis. Calibration issues and user interactive software development associated with this project will be discussed, as will examples of measurement projects and data reduction.

  16. Multi-level model for 2D human motion analysis and description

    Science.gov (United States)

    Foures, Thomas; Joly, Philippe

    2003-01-01

    This paper deals with the proposition of a model for human motion analysis in a video. Its main caracteristic is to adapt itself automatically to the current resolution, the actual quality of the picture, or the level of precision required by a given application, due to its possible decomposition into several hierarchical levels. The model is region-based to address some analysis processing needs. The top level of the model is only defined with 5 ribbons, which can be cut into sub-ribbons regarding to a given (or an expected) level of details. Matching process between model and current picture consists in the comparison of extracted subject shape with a graphical rendering of the model built on the base of some computed parameters. The comparison is processed by using a chamfer matching algorithm. In our developments, we intend to realize a platform of interaction between a dancer and tools synthetizing abstract motion pictures and music in the conditions of a real-time dialogue between a human and a computer. In consequence, we use this model in a perspective of motion description instead of motion recognition: no a priori gestures are supposed to be recognized as far as no a priori application is specially targeted. The resulting description will be made following a Description Scheme compliant with the movement notation called "Labanotation".

  17. Analysis of the motion of an extrasolar planet in a binary system

    CERN Document Server

    Plávalová, E

    2012-01-01

    We investigated the motion of planets revolving in binary systems in the frame of the particular case of the three body problem. We analysed of the motion an extrasolar plant (EP) revolving in a binary system by following conditions; a) a planet in a binary system revolves around one of the components (parent star), b) the distance between the stars components is greater than between the parent star and the orbiting planet (ratio of these two distances is a small parameter), c) the mass of the planet is smaller than the mass of the star, but is not negligible. The Hamiltonian of the system without short periodic terms was used. Expanded in the terms of the Legendre polynomial and truncated after the second order term depending on the one angular variable. In this case the solution of the system was obtained and the qualitative analysis of motion was done. We have applied this theory to real EPs. Analysis of the possible regions of motion are presented. It is shown that the case of the stable and unstable moti...

  18. Hilbert-Huang transform analysis of dynamic and earthquake motion recordings

    Science.gov (United States)

    Zhang, R.R.; Ma, S.; Safak, E.; Hartzell, S.

    2003-01-01

    This study examines the rationale of Hilbert-Huang transform (HHT) for analyzing dynamic and earthquake motion recordings in studies of seismology and engineering. In particular, this paper first provides the fundamentals of the HHT method, which consist of the empirical mode decomposition (EMD) and the Hilbert spectral analysis. It then uses the HHT to analyze recordings of hypothetical and real wave motion, the results of which are compared with the results obtained by the Fourier data processing technique. The analysis of the two recordings indicates that the HHT method is able to extract some motion characteristics useful in studies of seismology and engineering, which might not be exposed effectively and efficiently by Fourier data processing technique. Specifically, the study indicates that the decomposed components in EMD of HHT, namely, the intrinsic mode function (IMF) components, contain observable, physical information inherent to the original data. It also shows that the grouped IMF components, namely, the EMD-based low- and high-frequency components, can faithfully capture low-frequency pulse-like as well as high-frequency wave signals. Finally, the study illustrates that the HHT-based Hilbert spectra are able to reveal the temporal-frequency energy distribution for motion recordings precisely and clearly.

  19. Proper motion survey and kinematic analysis of the Rho Ophiuchi embedded cluster

    CERN Document Server

    Ducourant, C; Krone-Martins, A; Bontemps, S; Despois, D; Galli, P A B; Bouy, H; Campion, J F Le; Rapaport, M; Cuillandre, J C

    2016-01-01

    We aim at performing a kinematic census of young stellar objects (YSOs) in the Rho Ophiuchi F core and partially in the E core of the L1688 dark cloud. We run a proper motion program at the ESO New Technology Telescope (NTT) with the Son of ISAAC (SOFI) instrument over nine years in the near-infrared. We complemented these observations with various public image databases to enlarge the time base of observations and the field of investigation to 0.5 deg X 0.5 deg. We derived positions and proper motions for 2213 objects. From these, 607 proper motions were derived from SOFI observations with a ~1.8 mas/yr accuracy while the remaining objects were measured only from auxiliary data with a mean precision of about ~3 mas/yr. We performed a kinematic analysis of the most accurate proper motions derived in this work, which allowed us to separate cluster members from field stars and to derive the mean properties of the cluster. From the kinematic analysis we derived a list of 68 members and 14 candidate members, comp...

  20. Computational modeling and analysis for left ventricle motion using CT/Echo image fusion

    Science.gov (United States)

    Kim, Ji-Yeon; Kang, Nahyup; Lee, Hyoung-Euk; Kim, James D. K.

    2014-03-01

    In order to diagnose heart disease such as myocardial infarction, 2D strain through the speckle tracking echocardiography (STE) or the tagged MRI is often used. However out-of-plane strain measurement using STE or tagged MRI is inaccurate. Therefore, strain for whole organ which are analyzed by simulation of 3D cardiac model can be applied in clinical diagnosis. To simulate cardiac contraction in a cycle, cardiac physical properties should be reflected in cardiac model. The myocardial wall in left ventricle is represented as a transversely orthotropic hyperelastic material, with the fiber orientation varying sequentially from the epicardial surface, through about 0° at the midwall, to the endocardial surface. A time-varying elastance model is simulated to contract myocardial fiber, and physiological intraventricular systolic pressure curves are employed for the cardiac dynamics simulation in a cycle. And an exact description of the cardiac motion should be acquired in order that essential boundary conditions for cardiac simulation are obtained effectively. Real time cardiac motion can be acquired by using echocardiography and exact cardiac geometrical 3D model can be reconstructed using 3D CT data. In this research, image fusion technology from CT and echocardiography is employed in order to consider patient-specific left ventricle movement. Finally, longitudinal strain from speckle tracking echocardiography which is known to fit actual left ventricle deformation relatively well is used to verify these results.

  1. The spectral analysis of motion: An "open field" activity test example

    Directory of Open Access Journals (Sweden)

    Obradović Z.

    2013-01-01

    Full Text Available In this work we have described the new mathematical approach, with spectral analysis of the data to evaluate position and motion in the „„open field““ experiments. The aim of this work is to introduce several new parameters mathematically derived from experimental data by means of spectral analysis, and to quantitatively estimate the quality of the motion. Two original software packages (TRACKER and POSTPROC were used for transforming a video data to a log file, suitable for further computational analysis, and to perform analysis from the log file. As an example, results obtained from the experiments with Wistar rats in the „open field“ test are included. The test group of animals was treated with diazepam. Our results demonstrate that all the calculated parameters, such as movement variability, acceleration and deceleration, were significantly lower in the test group compared to the control group. We believe that the application of parameters obtained by spectral analysis could be of great significance in assessing the locomotion impairment in any kind of motion. [Projekat Ministarstva nauke Republike Srbije, br. III41007 i br. ON174028

  2. Error analysis of motion correction method for laser scanning of moving objects

    Science.gov (United States)

    Goel, S.; Lohani, B.

    2014-05-01

    The limitation of conventional laser scanning methods is that the objects being scanned should be static. The need of scanning moving objects has resulted in the development of new methods capable of generating correct 3D geometry of moving objects. Limited literature is available showing development of very few methods capable of catering to the problem of object motion during scanning. All the existing methods utilize their own models or sensors. Any studies on error modelling or analysis of any of the motion correction methods are found to be lacking in literature. In this paper, we develop the error budget and present the analysis of one such `motion correction' method. This method assumes availability of position and orientation information of the moving object which in general can be obtained by installing a POS system on board or by use of some tracking devices. It then uses this information along with laser scanner data to apply correction to laser data, thus resulting in correct geometry despite the object being mobile during scanning. The major application of this method lie in the shipping industry to scan ships either moving or parked in the sea and to scan other objects like hot air balloons or aerostats. It is to be noted that the other methods of "motion correction" explained in literature can not be applied to scan the objects mentioned here making the chosen method quite unique. This paper presents some interesting insights in to the functioning of "motion correction" method as well as a detailed account of the behavior and variation of the error due to different sensor components alone and in combination with each other. The analysis can be used to obtain insights in to optimal utilization of available components for achieving the best results.

  3. MRI中运动伪影分析%Analysis of Motion Artifacts in MRI

    Institute of Scientific and Technical Information of China (English)

    王昭波; 李文华; 王立忠; 曹庆选

    2013-01-01

    Objective To eliminate the motion artifact in MRI imaging , and improve the image quality.Method Analysis and classification of the motion artifacts in 5986 cases with MRI imaging in the most recent year in our hospital .Results According to the causes and characteristics, the MRI motion artifacts can be divided into random independent motion artifacts, respiratory motion artifacts, heart beat artifacts, large vascular pulsation artifacts and flow effect artifacts .Conclusions To improve the quality of MRI image and the diagnostic accuracy , it is important to understand and eliminate these motion artifacts .%目的:消除MRI中的运动伪影,改善MRI图像质量。方法总结我院最近一年的5986例 MRI检查图像,把其中有运动伪影的病例归纳分类,进行伪影分析。结果按照MRI运动伪影的成因及特点,可分为:随机自主运动伪影、呼吸运动伪影、心脏搏动伪影、大血管搏动伪影及流动效应伪影五大类。结论正确认识各种运动伪影的特点,应用相应的校正方法,对改善MRI质量,提高诊断准确率有重要意义。

  4. Depth information in natural environments derived from optic flow by insect motion detection system: A model analysis

    Directory of Open Access Journals (Sweden)

    Alexander eSchwegmann

    2014-08-01

    Full Text Available Knowing the depth structure of the environment is crucial for moving animals in many behavioral contexts, such as collision avoidance, targeting objects, or spatial navigation. An important source of depth information is motion parallax. This powerful cue is generated on the eyes during translatory self-motion with the retinal images of nearby objects moving faster than those of distant ones. To investigate how the visual motion pathway represents motion-based depth information we analyzed its responses to image sequences recorded in natural cluttered environments with a wide range of depth structures. The analysis was done on the basis of an experimentally validated model of the visual motion pathway of insects, with its core elements being correlation-type elementary motion detectors (EMDs. It is the key result of our analysis that the absolute EMD responses, i.e. the motion energy profile, represent the contrast-weighted nearness of environmental structures during translatory self-motion at a roughly constant velocity. In other words, the output of the EMD array highlights contours of nearby objects. This conclusion is largely independent of the scale over which EMDs are spatially pooled and was corroborated by scrutinizing the motion energy profile after eliminating the depth structure from the natural image sequences. Hence, the well-established dependence of correlation-type EMDs on both velocity and textural properties of motion stimuli appears to be advantageous for representing behaviorally relevant information about the environment in a computationally parsimonious way.

  5. Nonlocal continuous models for forced vibration analysis of two- and three-dimensional ensembles of single-walled carbon nanotubes

    Science.gov (United States)

    Kiani, Keivan

    2014-06-01

    Novel nonlocal discrete and continuous models are proposed for dynamic analysis of two- and three-dimensional ensembles of single-walled carbon nanotubes (SWCNTs). The generated extra van der Waals forces between adjacent SWCNTs due to their lateral motions are evaluated via Lennard-Jones potential function. Using a nonlocal Rayleigh beam model, the discrete and continuous models are developed for both two- and three-dimensional ensembles of SWCNTs acted upon by transverse dynamic loads. The capabilities of the proposed continuous models in capturing the vibration behavior of SWCNTs ensembles are then examined through various numerical simulations. A reasonably good agreement between the results of the continuous models and those of the discrete ones is also reported. The effects of the applied load frequency, intertube spaces, and small-scale parameter on the transverse dynamic responses of both two- and three-dimensional ensembles of SWCNTs are explained. The proposed continuous models would be very useful for dynamic analyses of large populated ensembles of SWCNTs whose discrete models suffer from both computational efforts and labor costs.

  6. Hemodynamics and wall mechanics of a compliance matching stent: in vitro and in vivo analysis.

    Science.gov (United States)

    Berry, Joel L; Manoach, Emil; Mekkaoui, Choukri; Rolland, Pierre H; Moore, J E; Rachev, Alexander

    2002-01-01

    Evidence is emerging that the abrupt compliance mismatch that exists at the junction between the stent ends and the host arterial wall disturbs both the vascular hemodynamics and the natural wall stress distribution. These stent-induced alterations are greatly reduced by smoothing the compliance mismatch between the stent and host vessel. A stent that provides this smooth transition in compliance, the compliance matching stent (CMS), has been developed. This study attempts to evaluate the hemodynamics and wall mechanical consequences of the CMS both in vitro and in vivo. Finite element analysis was used to assess the solid mechanical behavior (compliance and stress) of the CMS in a stent/artery hybrid structure. A similar analysis was performed with a Palmaz stent. In vivo hemodynamics and wall mechanical changes induced by the CMS were investigated in a swine model from direct measurements of flow, pressure, diameter, and histology in the stented segment of superficial femoral arteries after 7 days. Finite element analysis showed that the abrupt compliance mismatch was substantially smoothed between the vessel portions with and without the stent with CMS segments. Circumferential stress was also markedly reduced with the CMS compared to other stent. The in vivo results showed that the CMS was efficient in compliance matching and did not dampen flow or pressure waves downstream the stent. Concurrent histology showed limited thrombus and inflammatory cell accumulation around the stent struts. These results indicate that the stent/artery hybrid structure can be compliance matched with proper stent design and that this structure limits solid mechanical stress and hemodynamic disturbances. It remains to be seen whether compliance-matched vascular stents reduce in-stent restenosis.

  7. A measurement approach based on micro-Doppler maps for signature and motion analysis

    Science.gov (United States)

    Ricci, R.; Sona, A.

    2013-05-01

    In this paper, a novel and comprehensive measurement approach is proposed for the detection and analysis of human motion signature. The approach combines theoretical concepts and tools of micro-Doppler theory, image processing, and human modeling, in a original way. The attention is primarily focused on the description of the most meaningful parameters influencing the accuracy of the obtained signature. The ultimate purpose is to provide a framework through which organizing, comparing, and merging future research activities, ideas and results in the field of human motion signature analysis for security, health and disaster recovery purposes. Some simulation and experimental results underlying the feasibility and effectiveness of the measurement approach are also summarized and analyzed.

  8. Analysis of wave packet motion in frequency and time domain: oxazine 1.

    Science.gov (United States)

    Braun, Markus; Sobotta, Constanze; Dürr, Regina; Pulvermacher, Horst; Malkmus, Stephan

    2006-08-17

    Wave packet motion in the laser dye oxazine 1 in methanol is investigated by spectrally resolved transient absorption spectroscopy. The spectral range of 600-690 nm was accessible by amplified broadband probe pulses covering the overlap region of ground-state bleach and stimulated emission signal. The influence of vibrational wave packets on the optical signal is analyzed in the frequency domain and the time domain. For the analysis in the frequency domain an algorithm is presented that accounts for interference effects of neighbored vibrational modes. By this method amplitude, phase and decay time of vibrational modes are retrieved as a function of probe wavelength and distortions due to neighbored modes are reduced. The analysis of the data in the time domain yields complementary information on the intensity, central wavelength, and spectral width of the optical bleach spectrum due to wave packet motion.

  9. Flow induced vibration and stability analysis of multi wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Kyung Jae [Agency for Defense Development, Daejeon (Korea, Republic of); Choi, Jong Woon [Korean Intellectual Property Office, Daejeon (Korea, Republic of); Kim, Sung Kyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Song, Oh Seop [Chungnam National Univ., Daejeon (Korea, Republic of)

    2012-12-15

    The free vibration and flow induced flutter instability of cantilever multi wall carbon nanotubes conveying fluid are investigated and the nanotubes are modeled as thin-walled beams. The non-classical effects of the transverse shear, rotary inertia, warping inhibition, and van der Waals forces between two walls are incorporated into the structural model. The governing equations and associated boundary conditions are derived using Hamilton's principle. A numerical analysis is carried out by using the extended Galerkin method, which enables us to obtain more accurate solutions compared to the conventional Galerkin method. Cantilevered carbon nanotubes are damped with decaying amplitude for a flow velocity below a certain critical value. However, beyond this critical flow velocity, flutter instability may occur. The variations in the critical flow velocity with respect to both the radius ratio and length of the carbon nanotubes are investigated and pertinent conclusions are outlined. The differences in the vibration and instability characteristics between the Timoshenko beam theory and Euler beam theory are revealed. A comparative analysis of the natural frequencies and flutter characteristics of MWCNTs and SWCNTs is also performed.

  10. Automatic analysis of image of surface structure of cell wall-deficient EVC.

    Science.gov (United States)

    Li, S; Hu, K; Cai, N; Su, W; Xiong, H; Lou, Z; Lin, T; Hu, Y

    2001-01-01

    Some computer applications for cell characterization in medicine and biology, such as analysis of surface structure of cell wall-deficient EVC (El Tor Vibrio of Cholera), operate with cell samples taken from very small areas of interest. In order to perform texture characterization in such an application, only a few texture operators can be employed: the operators should be insensitive to noise and image distortion and be reliable in order to estimate texture quality from images. Therefore, we introduce wavelet theory and mathematical morphology to analyse the cellular surface micro-area image obtained by SEM (Scanning Electron Microscope). In order to describe the quality of surface structure of cell wall-deficient EVC, we propose a fully automatic computerized method. The image analysis process is carried out in two steps. In the first, we decompose the given image by dyadic wavelet transform and form an image approximation with higher resolution, by doing so, we perform edge detection of given images efficiently. In the second, we introduce many operations of mathematical morphology to obtain morphological quantitative parameters of surface structure of cell wall-deficient EVC. The obtained results prove that the method can eliminate noise, detect the edge and extract the feature parameters validly. In this work, we have built automatic analytic software named "EVC.CELL".

  11. Through Wall Radar Classification of Human Micro-Doppler Using Singular Value Decomposition Analysis.

    Science.gov (United States)

    Ritchie, Matthew; Ash, Matthew; Chen, Qingchao; Chetty, Kevin

    2016-08-31

    The ability to detect the presence as well as classify the activities of individuals behind visually obscuring structures is of significant benefit to police, security and emergency services in many situations. This paper presents the analysis from a series of experimental results generated using a through-the-wall (TTW) Frequency Modulated Continuous Wave (FMCW) C-Band radar system named Soprano. The objective of this analysis was to classify whether an individual was carrying an item in both hands or not using micro-Doppler information from a FMCW sensor. The radar was deployed at a standoff distance, of approximately 0.5 m, outside a residential building and used to detect multiple people walking within a room. Through the application of digital filtering, it was shown that significant suppression of the primary wall reflection is possible, significantly enhancing the target signal to clutter ratio. Singular Value Decomposition (SVD) signal processing techniques were then applied to the micro-Doppler signatures from different individuals. Features from the SVD information have been used to classify whether the person was carrying an item or walking free handed. Excellent performance of the classifier was achieved in this challenging scenario with accuracies up to 94%, suggesting that future through wall radar sensors may have the ability to reliably recognize many different types of activities in TTW scenarios using these techniques.

  12. Through Wall Radar Classification of Human Micro-Doppler Using Singular Value Decomposition Analysis

    Directory of Open Access Journals (Sweden)

    Matthew Ritchie

    2016-08-01

    Full Text Available The ability to detect the presence as well as classify the activities of individuals behind visually obscuring structures is of significant benefit to police, security and emergency services in many situations. This paper presents the analysis from a series of experimental results generated using a through-the-wall (TTW Frequency Modulated Continuous Wave (FMCW C-Band radar system named Soprano. The objective of this analysis was to classify whether an individual was carrying an item in both hands or not using micro-Doppler information from a FMCW sensor. The radar was deployed at a standoff distance, of approximately 0.5 m, outside a residential building and used to detect multiple people walking within a room. Through the application of digital filtering, it was shown that significant suppression of the primary wall reflection is possible, significantly enhancing the target signal to clutter ratio. Singular Value Decomposition (SVD signal processing techniques were then applied to the micro-Doppler signatures from different individuals. Features from the SVD information have been used to classify whether the person was carrying an item or walking free handed. Excellent performance of the classifier was achieved in this challenging scenario with accuracies up to 94%, suggesting that future through wall radar sensors may have the ability to reliably recognize many different types of activities in TTW scenarios using these techniques.

  13. Inertial Sensor-Based Two Feet Motion Tracking for Gait Analysis

    Directory of Open Access Journals (Sweden)

    Tran Nhat Hung

    2013-04-01

    Full Text Available Two feet motion is estimated for gait analysis. An inertial sensor is attached on each shoe and an inertial navigation algorithm is used to estimate the movement of both feet. To correct inter-shoe position error, a camera is installed on the right shoe and infrared LEDs are installed on the left shoe. The proposed system gives key gait analysis parameters such as step length, stride length, foot angle and walking speed. Also it gives three dimensional trajectories of two feet for gait analysis.

  14. Inertial sensor-based two feet motion tracking for gait analysis.

    Science.gov (United States)

    Hung, Tran Nhat; Suh, Young Soo

    2013-04-29

    Two feet motion is estimated for gait analysis. An inertial sensor is attached on each shoe and an inertial navigation algorithm is used to estimate the movement of both feet. To correct inter-shoe position error, a camera is installed on the right shoe and infrared LEDs are installed on the left shoe. The proposed system gives key gait analysis parameters such as step length, stride length, foot angle and walking speed. Also it gives three dimensional trajectories of two feet for gait analysis.

  15. Tracking and Motion Analysis of Crack Propagations in Crystals for Molecular Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Tsap, L V; Duchaineau, M; Goldgof, D B

    2001-05-14

    This paper presents a quantitative analysis for a discovery in molecular dynamics. Recent simulations have shown that velocities of crack propagations in crystals under certain conditions can become supersonic, which is contrary to classical physics. In this research, they present a framework for tracking and motion analysis of crack propagations in crystals. It includes line segment extraction based on Canny edge maps, feature selection based on physical properties, and subsequent tracking of primary and secondary wavefronts. This tracking is completely automated; it runs in real time on three 834-image sequences using forty 250 MHZ processors. Results supporting physical observations are presented in terms of both feature tracking and velocity analysis.

  16. Age-Related Impairment of Quality of Joint Motion in Vibroarthrographic Signal Analysis

    Directory of Open Access Journals (Sweden)

    Dawid Bączkowicz

    2015-01-01

    Full Text Available Aging is associated with degenerative changes in articular surfaces leading to quantitative and qualitative impairment of joint motion. Therefore, the aim of this study is to evaluate an age-related quality of the patellofemoral joint (PFJ motion in the vibroarthrographic (VAG signal analysis. Two hundred and twenty individuals were enrolled in this study and divided into five groups according to age. The VAG signals were collected during flexion/extension knee motion using an acceleration sensor and described using four parameters (VMS, P1, P2, and H. We observed that values of parameters VMS, P1, and P2 increase in accordance with the age, but H level decreases. The most significant differences were achieved between the youngest and the oldest participants’ groups. Moreover, we show that parameters VMS, P1, and P2 positively correlate with age, contrary to negatively associated H parameter. Our results suggest that the impairment of joint motion is a result of age-related osteoarticular degenerative changes.

  17. Thermal Property Analysis of Axle Load Sensors for Weighing Vehicles in Weigh-in-Motion System

    Directory of Open Access Journals (Sweden)

    Piotr Burnos

    2016-12-01

    Full Text Available Systems which permit the weighing of vehicles in motion are called dynamic Weigh-in-Motion scales. In such systems, axle load sensors are embedded in the pavement. Among the influencing factors that negatively affect weighing accuracy is the pavement temperature. This paper presents a detailed analysis of this phenomenon and describes the properties of polymer, quartz and bending plate load sensors. The studies were conducted in two ways: at roadside Weigh-in-Motion sites and at a laboratory using a climate chamber. For accuracy assessment of roadside systems, the reference vehicle method was used. The pavement temperature influence on the weighing error was experimentally investigated as well as a non-uniform temperature distribution along and across the Weigh-in-Motion site. Tests carried out in the climatic chamber allowed the influence of temperature on the sensor intrinsic error to be determined. The results presented clearly show that all kinds of sensors are temperature sensitive. This is a new finding, as up to now the quartz and bending plate sensors were considered insensitive to this factor.

  18. Thermal Property Analysis of Axle Load Sensors for Weighing Vehicles in Weigh-in-Motion System.

    Science.gov (United States)

    Burnos, Piotr; Gajda, Janusz

    2016-12-15

    Systems which permit the weighing of vehicles in motion are called dynamic Weigh-in-Motion scales. In such systems, axle load sensors are embedded in the pavement. Among the influencing factors that negatively affect weighing accuracy is the pavement temperature. This paper presents a detailed analysis of this phenomenon and describes the properties of polymer, quartz and bending plate load sensors. The studies were conducted in two ways: at roadside Weigh-in-Motion sites and at a laboratory using a climate chamber. For accuracy assessment of roadside systems, the reference vehicle method was used. The pavement temperature influence on the weighing error was experimentally investigated as well as a non-uniform temperature distribution along and across the Weigh-in-Motion site. Tests carried out in the climatic chamber allowed the influence of temperature on the sensor intrinsic error to be determined. The results presented clearly show that all kinds of sensors are temperature sensitive. This is a new finding, as up to now the quartz and bending plate sensors were considered insensitive to this factor.

  19. Cilia walls influence on peristaltically induced motion of magneto-fluid through a porous medium at moderate Reynolds number: Numerical study

    Directory of Open Access Journals (Sweden)

    R.E. Abo-Elkhair

    2017-04-01

    Full Text Available This article addresses, effects of a magneto-fluid through a Darcy flow model with oscillatory wavy walled whose inner surface is ciliated. The equations that governing the flow are modeled without using any approximations. Adomian Decomposition Method (ADM is used to evaluate the solution of our system of nonlinear partial differential equations. Stream function, velocity and pressure gradient components are obtained by using the vorticity formula. The effects for our arbitrary physical parameters on flow characteristics are analyzed by plotting diagrams and discussed in details. With the help of stream lines the trapping mechanism has also been discussed. The major outcomes for the ciliated channel walls are: The axial velocity is higher without a ciliated walls than that for a ciliated walls and an opposite behaviour is shown near the ciliated channel walls. The pressure gradients in both directions are higher for a ciliated channel walls. More numbers of the trapped bolus in the absent of the eccentricity of the cilia elliptic path.

  20. Spatial Finite Element Analysis for Dynamic Response of Curved Thin-Walled Box Girder Bridges

    Directory of Open Access Journals (Sweden)

    Yinhui Wang

    2016-01-01

    Full Text Available According to the flexural and torsional characteristics of curved thin-walled box girder with the effect of initial curvature, 7 basic displacements of curved box girder are determined. And then the strain-displacement calculation correlations were established. Under the curvilinear coordinate system, a three-noded curved girder finite element which has 7 degrees of freedom per node for the vibration characteristic and dynamic response analysis of curved box girder is constructed. The shape functions are used as the interpolation functions of variable curvature and variable height to accommodate to the variation of curvature and section height. A MATLAB numerical analysis program has been implemented.

  1. Consistent Fundamental Matrix Estimation in a Quadratic Measurement Error Model Arising in Motion Analysis

    OpenAIRE

    Kukush, A.; Markovsky, I.; Van Huffel, S.

    2002-01-01

    Consistent estimators of the rank-deficient fundamental matrix yielding information on the relative orientation of two images in two-view motion analysis are derived. The estimators are derived by minimizing a corrected contrast function in a quadratic measurement error model. In addition, a consistent estimator for the measurement error variance is obtained. Simulation results show the improved accuracy of the newly proposed estimator compared to the ordinary total least-squares estimator.

  2. Heat and mass transfer analysis of unsteady MHD nanofluid flow through a channel with moving porous walls and medium

    Directory of Open Access Journals (Sweden)

    Muhammad Zubair Akbar

    2016-04-01

    Full Text Available The paper presents the numerical study of heat and mass transfer analysis in a viscous unsteady MHD nanofluid flow through a channel with porous walls and medium in the presence of metallic nanoparticles. The two cases for effective thermal conductivity are discussed in the analysis through H-C model. The impacts of the governing parameters on the flow, heat and mass transfer aspects of the issue are talked about. Under the patronage of small values of permeable Reynolds number and relaxation/contraction parameter, we locate that, when wall contraction is together with suction, flow turning is encouraged close to the wall where the boundary layer is shaped. On the other hand, when the wall relaxation is coupled with injection, the flow adjacent to the porous walls decreased. The outcome of the exploration may be beneficial for applications of biotechnology. Numerical solutions for the velocity, heat and mass transfer rate at the boundary are obtained and analyzed.

  3. A comparative analysis of modal motions for the gyroscopic and non-gyroscopic two degree-of-freedom conservative systems

    Science.gov (United States)

    Yang, Xiao-Dong; An, Hua-Zhen; Qian, Ying-Jing; Zhang, Wei; Melnik, Roderick V. N.

    2016-12-01

    The synchronous in-unison motions in vibrational mechanics and the non-synchronous out-of-unison motions are the most frequently found periodic motions in every fields of science and everywhere in the universe. In contrast to the in-unison normal modes, the out-of-unison complex modes feature a π/2 phase difference. By the complex mode analysis we classify the out-of-unison planar motion into two types, gyroscopic motions and elliptic motions. It is found that the gyroscopic and elliptic motions have different characteristics for a two degree-of-freedom (2DOF) system. The gyroscopic motion involves two distinct frequencies with, respectively, two corresponding complex modes. However, the elliptic motion the nonlinear non-gyroscopic 2DOF system with repeated frequencies involves only single frequency with corresponding two complex modes. The study of the differences and similarities of the gyroscopic and elliptic modes sheds new light on the in-depth mechanism of the planar motions in the universe and the man-made engineering systems.

  4. Analysis of Building with and with out Shear Wall at Various Heights and Variation of Zone III and Zone V

    Directory of Open Access Journals (Sweden)

    P.Kalpana

    2016-12-01

    Full Text Available It is well recognized that the incorporation of lateral load resisting systems in the form of shear walls, bracing systems etc. improve the structural performance of buildings subjected to lateral forces due to earthquake excitation. The seismic behavior of buildings is strongly affected by the arrangement of shear walls, the rigidity of floors and the connections of floors to the walls. The building with structural shear walls Improve the lateral load resistance. In the present project, an analytical parameter study is done for the structural shear walls with varying height for different models. The load combinations are consideration as per IS 1893 (Part-1:2002. The result in terms of axial forces, lateral displacement and bending moment in the structural shear walls with varying height are compared for different building models considered.As well as two reinforced concrete framed regular buildings with different zones locations of shear walls situated in seismic zone III and zone V have been analyzed in this study. Five-storied buildings were taken with shear-walls and without shear-walls. The design is above verified for this same structure using extended three dimensional analysis of buildings (STAAD Pro V8i software

  5. Including the effect of motion artifacts in noise and performance analysis of dual-energy contrast-enhanced mammography.

    Science.gov (United States)

    Allec, N; Abbaszadeh, S; Scott, C C; Lewin, J M; Karim, K S

    2012-12-21

    In contrast-enhanced mammography (CEM), the dual-energy dual-exposure technique, which can leverage existing conventional mammography infrastructure, relies on acquiring the low- and high-energy images using two separate exposures. The finite time between image acquisition leads to motion artifacts in the combined image. Motion artifacts can lead to greater anatomical noise in the combined image due to increased mismatch of the background tissue in the images to be combined, however the impact has not yet been quantified. In this study we investigate a method to include motion artifacts in the dual-energy noise and performance analysis. The motion artifacts are included via an extended cascaded systems model. To validate the model, noise power spectra of a previous dual-energy clinical study are compared to that of the model. The ideal observer detectability is used to quantify the effect of motion artifacts on tumor detectability. It was found that the detectability can be significantly degraded when motion is present (e.g., detectability of 2.5 mm radius tumor decreased by approximately a factor of 2 for translation motion on the order of 1000 μm). The method presented may be used for a more comprehensive theoretical noise and performance analysis and fairer theoretical performance comparison between dual-exposure techniques, where motion artifacts are present, and single-exposure techniques, where low- and high-energy images are acquired simultaneously and motion artifacts are absent.

  6. The development and validation of hand motion analysis to evaluate competency in central line catheterization.

    Science.gov (United States)

    Clinkard, David; Holden, Matthew; Ungi, Tamas; Messenger, David; Davison, Colleen; Fichtinger, Gabor; McGraw, Robert

    2015-02-01

    Traditionally, technical skills proficiency has been assessed by direct observation. While direct observation and feedback are essential components in technical skills learning, they demand considerable investment of faculty time, and as an assessment tool, direct observation is inherently subjective and has been criticized as unreliable. The purpose of this study was to determine if quantitative electromagnetic motion tracking is feasible and can discriminate between experts and nonexperts during simulated ultrasound (US)-guided insertion of a central venous catheter (CVC) guidewire. Ten nonexperts (junior emergency medicine residents) and 10 experts (critical care fellows or attending physicians) were recruited. Electromagnetic sensor probes were used to capture hand motion during an US-guided internal jugular cannulation on a standardized manikin. Hand, US, and needle motion were analyzed for the following metrics: total path length, total time, translational movements, and rotational movements. Subjects were also videotaped and evaluated using a modified, validated global rating scale (GRS) by a blinded expert. There was a significant difference in almost all examined motion parameters between experts and nonexperts. Experts took 66% less time (50.2 seconds vs. 148.7 seconds, p 0.74) to a previously published, modified GRS. Electromagnetic hand and instrument motion analysis is technically feasible for assessing competence in US-guided insertion of a CVC guidewire in a simulation setting. In showing that it discriminates between the performances of nonexperts and experts, this study has provided evidence for construct validity. It also shows excellent correlation with a modified version of a previously validated GRS, providing evidence of concurrent validity. © 2015 by the Society for Academic Emergency Medicine.

  7. Vibro-acoustic modelling of aircraft double-walls with structural links using Statistical Energy Analysis

    Science.gov (United States)

    Campolina, Bruno L.

    The prediction of aircraft interior noise involves the vibroacoustic modelling of the fuselage with noise control treatments. This structure is composed of a stiffened metallic or composite panel, lined with a thermal and acoustic insulation layer (glass wool), and structurally connected via vibration isolators to a commercial lining panel (trim). The goal of this work aims at tailoring the noise control treatments taking design constraints such as weight and space optimization into account. For this purpose, a representative aircraft double-wall is modelled using the Statistical Energy Analysis (SEA) method. Laboratory excitations such as diffuse acoustic field and point force are addressed and trends are derived for applications under in-flight conditions, considering turbulent boundary layer excitation. The effect of the porous layer compression is firstly addressed. In aeronautical applications, compression can result from the installation of equipment and cables. It is studied analytically and experimentally, using a single panel and a fibrous uniformly compressed over 100% of its surface. When compression increases, a degradation of the transmission loss up to 5 dB for a 50% compression of the porous thickness is observed mainly in the mid-frequency range (around 800 Hz). However, for realistic cases, the effect should be reduced since the compression rate is lower and compression occurs locally. Then the transmission through structural connections between panels is addressed using a four-pole approach that links the force-velocity pair at each side of the connection. The modelling integrates experimental dynamic stiffness of isolators, derived using an adapted test rig. The structural transmission is then experimentally validated and included in the double-wall SEA model as an equivalent coupling loss factor (CLF) between panels. The tested structures being flat, only axial transmission is addressed. Finally, the dominant sound transmission paths are

  8. Analysis of the temperature distribution of a water wall in the furnace of a supercritical steam power plant

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Norihide; Yagi, Nobuyoshi; Shibayama, Motoaki; Hayasaka, Hiroshi

    1988-07-25

    It is one of the important subjects for maintenance and management of modern boilers to establish the technology for estimating the residual life of a water wall tube composing a boiler furnace for a thermal power plant. Various studies on the residual life of material itself for a boiler water-wall tube have so far been in progress, but concerning a temperature of a water wall tube at a particular place inside a boiler furnace, the development of a practical method of analysis estimating the amount of the radiant heat transfer has not so far been progressed. Accordingly, in this report, a practical method for obtaining the temperature distribution of a water wall tube was examined and an idea that the radiant heat ray method was used for the analysis of radiant heat transfer and at the same time, the actual result of the operation was used for steam flow rate, etc. was elaborated and brought into operation. As a result, the following was revealed inter alia: (1) The heat flux became the maximum around the uppermost stages of the burners of the front and rear walls. (2) The temperature of a tube wall became the maximum around the uppermost stages of the burners in the center of the wall. (3) Deviation of the flow distribution affected the wall tube temperature considerably. The above is considered to suggest the adequacy of this analytical method. (12 figs, 9 refs)

  9. Theoretical analysis of the influence of flexoelectric effect on the defect site in nematic inversion walls

    Science.gov (United States)

    Gui-Li, Zheng; Hui, Zhang; Wen-Jiang, Ye; Zhi-Dong, Zhang; Hong-Wei, Song; Li, Xuan

    2016-03-01

    Based on the experimental phenomena of flexoelectric response at defect sites in nematic inversion walls conducted by Kumar et al., we gave the theoretical analysis using the Frank elastic theory. When a direct-current electric field normal to the plane of the substrate is applied to the parallel aligned nematic liquid crystal cell with weak anchoring, the rotation of ±1 defects in the narrow inversion walls can be exhibited. The free energy of liquid crystal molecules around the +1 and -1 defect sites in the nematic inversion walls under the electric field was formulated and the electric-field-driven structural changes at the defect site characterized by polar and azimuthal angles of the local director were simulated. The results reveal that the deviation of azimuthal angle induced by flexoelectric effect are consistent with the switching of extinction brushes at the +1 and -1 defects obtained in the experiment conducted by Kumar et al. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374087, 11274088, and 11304074), the Natural Science Foundation of Hebei Province, China (Grant Nos. A2014202123 and A2016202282), the Research Project of Hebei Education Department, China (Grant Nos. QN2014130 and QN2015260), and the Key Subject Construction Project of Hebei Province University, China.

  10. Machining Deformation Prediction of Thin-Walled Part Based on Finite Element Analysis

    Institute of Scientific and Technical Information of China (English)

    Hongxiang Wang; Yabin Tang; Zhanshan Liu; Shi Gao

    2015-01-01

    For the problems of machining distortion and the low accepted product during milling process of aluminum alloy thin⁃walled part, this paper starts from the analysis of initial stress state in material preparation process, the change process of residual stress within aluminum alloy pre⁃stretching plate is researched, and the distribution law of residual stress is indirectly obtained by delamination measurement methods, so the effect of internal residual stress on machining distortion is considered before finite element simulation. Considering the coupling effects of residual stress, dynamic milling force and clamping force on machining distortion, a three⁃dimensional dynamic finite element simulation model is established, and the whole cutting process is simulated from the blank material to finished product, a novel prediction method is proposed, which can availably predict the machining distortion accurately. The machining distortion state of the thin⁃walled part is achieved at different processing steps, the machining distortion of the thin⁃walled part is detected with three coordinate measuring machine tools, show that the simulation results are in good agreement with experimental data.

  11. Finite Element Analysis based Optimization of Magnetic Adhesion Module for Concrete Wall Climbing Robot

    Directory of Open Access Journals (Sweden)

    MD Omar faruq Howlader

    2015-08-01

    Full Text Available Wall climbing robot can provide easier accessibility to tall structures for Non Destructive Testing (NDT and improve working environments of human operators. However, existing adhesion mechanism for climbing robots such as vortex, electromagnet etc. are still at development stage and offer no feasible adhesion mechanism. As a result, few practical products have been developed for reinforced concrete surfaces, though wall-climbing robots have been researched for many years. This paper proposes a novel magnetic adhesion mechanism for wall-climbing robot for reinforced concrete surface. Mechanical design parameters such as distance between magnets, the yoke thickness, and magnet arrangements have been investigated by Finite Element Analysis (FEA. The adhesion module can be attached under the chassis of a prototype robot. The magnetic flux can penetrate maximum concrete cover of 30 mm and attain adhesion force of 121.26 N. The prototype provides high Force-to-Weight ratio compared to other reported permanent magnet based robotic systems. Both experiment and simulation results prove that the magnetic adhesion mechanism can generate efficient adhesion force for the climbing robot to operate on vertical reinforced concrete structures.

  12. An Approximate Analysis of the Inner Wall Loading of a Bimetallic Camera Shell of Reusable Rocket Engine

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2016-01-01

    Full Text Available Various technical devices quite widely use bimetallic shells as the structural elements. A chamber combustion design of the liquid rocket engine (LRE is a typical use of the bimetallic shells.In LRE operation a combustion chamber shell is subject to intense thermal and mechanical effects, which necessitates cooling. A cooling shell path is formed by a gap between its inner and outer walls connected to each other by milled or grooved spacer ribs. The outer wall of the shell serves as a load-bearing element, the inner wall is in direct contact with high-temperature combustion products and exposed to intense heat. The difference in functions of shell walls calls for their manufacturing from different materials with different thermophysical and mechanical properties.Interaction between the shell walls of different materials in heating and cooling leads to emerging thermal strains of various values in the walls. In terms of mechanical properties the inner wall material, usually ranks below the outer wall material strength, which uses the high strength stainless steel 12Х21Н5Т. The inner wall is typically made from copper-based highly heat-conductive alloys. (eg.: chromium bronze. Therefore, the result of the difference in temperature deformations, arising in the walls,  is inelastic nonisothermal strain of the inner wall material with (usually elastic behavior of the outer wall material.For reusable LRE, a cyclic sequence of the loading steps of the inner wall can lead to accumulating damages in its material because of the low-cycle fatigue and cause destruction of the wall or the loss of the cooling tract tightness. The main parameter that determines the level of low-cycle fatigue, is an absolute value of the accumulated inelastic strain (both plastic and evolving over time creep deformation. Quantitative evaluation of this parameter involves analysis of the inner wall loading with multiple starts and shutdowns of LRE. The paper represents an

  13. Determination of viscoelastic properties by analysis of probe-particle motion in molecular simulations

    Science.gov (United States)

    Karim, Mir; Kohale, Swapnil C.; Indei, Tsutomu; Schieber, Jay D.; Khare, Rajesh

    2012-11-01

    We present a technique for the determination of viscoelastic properties of a medium by tracking the motion of an embedded probe particle by using molecular dynamics simulations. The approach involves the analysis of the simulated particle motion by continuum theory; it is shown to work in both passive and active modes. We demonstrate that, for passive rheology, an analysis based on the generalized Stokes-Einstein relationship is not adequate to obtain the values of the viscoelastic moduli over the frequency range studied. For both passive and active modes, it is necessary to account for the medium and particle inertia when analyzing the particle motion. For a polymer melt system consisting of short chains, the values calculated from the proposed approach are in good quantitative agreement with previous literature results that were obtained using completely different simulation approaches. The proposed particle rheology simulation technique is general and could provide insight into the characterization of the mechanical properties in biological systems, such as cellular environments and polymeric systems, such as thin films and nanocomposites that exhibit spatial variation in properties over the nanoscale.

  14. On using the Microsoft Kinect$^{\\rm TM}$ sensor in the analysis of human motion

    CERN Document Server

    Malinowski, M J; Roth, S

    2014-01-01

    The present paper explores the possibility of using the Microsoft Kinect$^{\\rm TM}$ sensor in the analysis of human motion; we attempt the validation of the output of the original version of the sensor on the basis of a marker-based system which is assumed to provide the reference solution (baseline, `ground truth'). The similarity between the two outputs is assessed after comparing a number of waveforms, representing the variation within the gait cycle of quantities which are commonly used in order to characterise (and model) motion. The data acquisition involved a commercially-available treadmill and five velocity settings: walking data were acquired at $5$ km/h, running data at $8$, $10$, $11$, and $12$ km/h. The analysis revealed three problems with such an application of the Kinect sensor: the systematic underestimation of the knee angle by about $25 \\%$, the appearance of artefacts in the motion of the lower leg of the subject, and the inability of the sensor to capture reliably the details regarding th...

  15. Comparative abilities of Microsoft Kinect and Vicon 3D motion capture for gait analysis.

    Science.gov (United States)

    Pfister, Alexandra; West, Alexandre M; Bronner, Shaw; Noah, Jack Adam

    2014-07-01

    Biomechanical analysis is a powerful tool in the evaluation of movement dysfunction in orthopaedic and neurologic populations. Three-dimensional (3D) motion capture systems are widely used, accurate systems, but are costly and not available in many clinical settings. The Microsoft Kinect™ has the potential to be used as an alternative low-cost motion analysis tool. The purpose of this study was to assess concurrent validity of the Kinect™ with Brekel Kinect software in comparison to Vicon Nexus during sagittal plane gait kinematics. Twenty healthy adults (nine male, 11 female) were tracked while walking and jogging at three velocities on a treadmill. Concurrent hip and knee peak flexion and extension and stride timing measurements were compared between Vicon and Kinect™. Although Kinect measurements were representative of normal gait, the Kinect™ generally under-estimated joint flexion and over-estimated extension. Kinect™ and Vicon hip angular displacement correlation was very low and error was large. Kinect™ knee measurements were somewhat better than hip, but were not consistent enough for clinical assessment. Correlation between Kinect™ and Vicon stride timing was high and error was fairly small. Variability in Kinect™ measurements was smallest at the slowest velocity. The Kinect™ has basic motion capture capabilities and with some minor adjustments will be an acceptable tool to measure stride timing, but sophisticated advances in software and hardware are necessary to improve Kinect™ sensitivity before it can be implemented for clinical use.

  16. Motion Analysis of an Electric Vehicle with Two Independent Drive Motors

    Institute of Scientific and Technical Information of China (English)

    陈勇; 陈全世; 孙逢春

    2004-01-01

    Motion analyses are performed with the help of stability and simulation analysis, which can provide theoretical bases for applications of an electric vehicle with two independent drive motors. Compared with one-motor drive electric vehicle, the two-motor drive electric vehicle has the advantage of easy layout, simple power train and good drivability and handling characteristics. Analysis shows the method connecting armatures of two DC motors in parallel can function as mechanical differential without a steering sensor, which can simplify structure and increase reliability of the controller. Computer simulations and experiment are carried out to verify conclusions.

  17. Tissue motion tracking at the edges of a radiation treatment field using local optical flow analysis

    Science.gov (United States)

    Teo, P. T.; Pistorius, S.

    2014-03-01

    This paper investigates the feasibility and accuracy of tracking the motion of an intruding organ-at-risk (OAR) at the edges of a treatment field using a local optical flow analysis of electronic portal images. An intruding OAR was simulated by modifying the portal images obtained by irradiating a programmable phantom's lung tumour. A rectangular treatment aperture was assumed and the edges of the beam's eye view (BEV) were partitioned into clusters/grids according to the width of the multi-leaf collimators (MLC). The optical flow velocities were calculated and the motion accuracy in these clusters was analysed. A velocity error of 0.4 ± 1.4 mm/s with a linearity of 1.04 for tracking an object intruding at 10mm/s (max) was obtained.

  18. Initial assessment of facial nerve paralysis based on motion analysis using an optical flow method.

    Science.gov (United States)

    Samsudin, Wan Syahirah W; Sundaraj, Kenneth; Ahmad, Amirozi; Salleh, Hasriah

    2016-01-01

    An initial assessment method that can classify as well as categorize the severity of paralysis into one of six levels according to the House-Brackmann (HB) system based on facial landmarks motion using an Optical Flow (OF) algorithm is proposed. The desired landmarks were obtained from the video recordings of 5 normal and 3 Bell's Palsy subjects and tracked using the Kanade-Lucas-Tomasi (KLT) method. A new scoring system based on the motion analysis using area measurement is proposed. This scoring system uses the individual scores from the facial exercises and grades the paralysis based on the HB system. The proposed method has obtained promising results and may play a pivotal role towards improved rehabilitation programs for patients.

  19. Evaluation of skin and muscular deformations in a non-rigid motion analysis

    Science.gov (United States)

    Goffredo, Michela; Carli, Marco; Conforto, Silvia; Bibbo, Daniele; Neri, Alessandro; D'Alessio, Tommaso

    2005-04-01

    During contraction and stretching, muscles change shape and size, and produce a deformation of skin tissues and a modification of the body segment shape. In human motion analysis, it is indispensable to take into account this phenomenon and thus approximating body limbs to rigid structures appears as restrictive. The present work aims at evaluating skin and muscular deformation, and at modeling body segment elastic behavior by analysing video sequences that capture a sport gesture. The soft tissue modeling is accomplished by using triangular meshes that automatically adapt to the body segment during the execution of a static muscle contraction. The adaptive triangular mesh is built on reference points whose motion is estimated by using the technique based on Gauss Laguerre Expansion. Promising results have been obtained by applying the proposed method to a video sequence, where an upper arm isometric contraction was present.

  20. Representation of the Physiological Factors Contributing to Postflight Changes in Functional Performance Using Motion Analysis Software

    Science.gov (United States)

    Parks, Kelsey

    2010-01-01

    Astronauts experience changes in multiple physiological systems due to exposure to the microgravity conditions of space flight. To understand how changes in physiological function influence functional performance, a testing procedure has been developed that evaluates both astronaut postflight functional performance and related physiological changes. Astronauts complete seven functional and physiological tests. The objective of this project is to use motion tracking and digitizing software to visually display the postflight decrement in the functional performance of the astronauts. The motion analysis software will be used to digitize astronaut data videos into stick figure videos to represent the astronauts as they perform the Functional Tasks Tests. This project will benefit NASA by allowing NASA scientists to present data of their neurological studies without revealing the identities of the astronauts.

  1. Capacity of unreinforced rammed earth walls subject to lateral wind force: elastic analysis versus ultimate strength analysis.

    OpenAIRE

    Ciancio, D.; Augarde, C.

    2013-01-01

    Cement-stabilized rammed earth walls are an increasingly common form of construction in certain parts of the world, bringing considerable potential to reduce the carbon footprints of buildings. However, there is relatively little advice to designers wishing to use these construction materials at present, as compared to established materials such as concrete. This paper discusses the use of two proposed analysis procedures to calculate the capacity of unreinforced cement-stabilized rammed eart...

  2. Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis.

    Science.gov (United States)

    Bernardina, Gustavo R D; Cerveri, Pietro; Barros, Ricardo M L; Marins, João C B; Silvatti, Amanda P

    2016-01-01

    Action sport cameras (ASC) are currently adopted mainly for entertainment purposes but their uninterrupted technical improvements, in correspondence of cost decreases, are going to disclose them for three-dimensional (3D) motion analysis in sport gesture study and athletic performance evaluation quantitatively. Extending this technology to sport analysis however still requires a methodologic step-forward to making ASC a metric system, encompassing ad-hoc camera setup, image processing, feature tracking, calibration and 3D reconstruction. Despite traditional laboratory analysis, such requirements become an issue when coping with both indoor and outdoor motion acquisitions of athletes. In swimming analysis for example, the camera setup and the calibration protocol are particularly demanding since land and underwater cameras are mandatory. In particular, the underwater camera calibration can be an issue affecting the reconstruction accuracy. In this paper, the aim is to evaluate the feasibility of ASC for 3D underwater analysis by focusing on camera setup and data acquisition protocols. Two GoPro Hero3+ Black (frequency: 60Hz; image resolutions: 1280×720/1920×1080 pixels) were located underwater into a swimming pool, surveying a working volume of about 6m3. A two-step custom calibration procedure, consisting in the acquisition of one static triad and one moving wand, carrying nine and one spherical passive markers, respectively, was implemented. After assessing camera parameters, a rigid bar, carrying two markers at known distance, was acquired in several positions within the working volume. The average error upon the reconstructed inter-marker distances was less than 2.5mm (1280×720) and 1.5mm (1920×1080). The results of this study demonstrate that the calibration of underwater ASC is feasible enabling quantitative kinematic measurements with accuracy comparable to traditional motion capture systems.

  3. Computational thermo-fluid exploratory design analysis for complex ITER first wall/shield components

    Energy Technology Data Exchange (ETDEWEB)

    Youchison, Dennis L. [Sandia National Laboratories, Albuquerque, NM 87185 (United States)], E-mail: dlyouch@sandia.gov; Natoni, Greg [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Narula, Manmeet; Ying, Alice [University of California, Los Angeles, CA 90095 (United States)

    2008-12-15

    Engineers in the ITER US Party Team used several computational fluid dynamics codes to evaluate design concepts for the ITER first wall panels and the neutron shield modules. The CFdesign code enabled them to perform design studies of modules 7 and 13 very efficiently. CFdesign provides a direct interface to the CAD program, CATIA v5. The geometry input and meshing are greatly simplified. CFdesign is a finite element code, rather than a finite volume code. Flow experiments and finite volume calculations from SC-Tetra, Fluent and CFD2000 verified the CFdesign results. Several new enhancements allow CFdesign to export temperatures, pressures and convective heat transfer coefficients to other finite element models for further analysis. For example, these loads and boundary conditions directly feed into codes such as ABAQUS to perform stress analysis. In this article, we review the use of 2- and 4-mm flow driver gaps in the shield modules and the use of 1-mm gaps along the tee-vane in the front water header to obtain a good flow distribution in both the first wall and shield modules for 7 and 13. Plasma heat flux as well as neutron heating derived from MCNP calculations is included in the first wall and shield module analyses. We reveal the non-uniformity of the convective heat transfer coefficient inside complex 3D geometries exposed to a one-sided heat flux and non-uniform volumetric heating. Most models consisted of 3-4 million tetrahedron elements. We obtained temperature and velocity distributions, as well as pressure drop information, for models of nearly exact geometry compared to the CATIA fabrication models. We also describe the coupling to thermal stress analysis in ABAQUS. The results presented provide confidence that the preliminary design of these plasma facing components will meet ITER requirements.

  4. Analysis of the Sea Fog in the Sea Around the Great Wall Station,Antarctica

    Institute of Scientific and Technical Information of China (English)

    黄耀荣; 薛振和

    2001-01-01

    The synoptic analysis of sea fog in western Antarctic sea region is made based on the observation data in the Chinese Antarctic station, Great Wall Station, from December 1994 to November 1995, and the facsimile weather charts issued by Chile. It is found that more than 90% fog in this region is the advection cooling fog. Also, the synoptic mechanism of the fog creation and distinction is discussed by analyzing the pressure field, the temperature field and the upperlevel stratification. Finally, the focus of attention in forecasting fog is pointed out.

  5. PARAMETRIC ANALYSIS OF THE BUCKLING RESISTANCE OF THE SILO STEEL WALL

    OpenAIRE

    Skejić, Davor; Cavor, Marija

    2015-01-01

    The latest final draft amendment EN 1993-4-1:2007/FprA1 brings many changes that will likely soon become valid. In this article, we assess the issue of designing steel silo walls from perspective of the proposed changes related to assessing their buckling resistance. We performed a parametric analysis, comparing the current standard, HRN EN 1993-4-1, to the proposed amendment, EN 1993-4-1:2007/FprA1, accounting for the silo fabrication quality parameter as well as variations in steel quality,...

  6. Dynamic response of flexible retaining walls

    Energy Technology Data Exchange (ETDEWEB)

    Younan, A.H.; Veletsos, A.S.; Bandyopadhyay, K.

    1997-01-01

    Making use of an extension of a recently proposed, relatively simple, approximate method of analysis, a critical evaluation is made of the response to horizontal ground shaking of flexible walls retaining a uniform, linear, viscoelastic stratum of constant thickness and semiinfinite extent in the horizontal direction. Both cantilever and top-supported walls are examined. Following a detailed description of the method and of its rate of convergence, comprehensive numerical solutions are presented that elucidate the action of the system and the effects of the various parameters involved. The parameters varied include the flexibility of the wall, the condition of top support, and the characteristics of the ground motion. The effects of both harmonic base motions and an actual earthquake record are examined. Special attention is paid to the effects of long-period, effectively static excitations. A maximum dynamic response is then expressed as the product of the corresponding static response and an appropriate amplification or deamplification factor. The response quantities examined include the displacements of the wall relative to the moving base, the dynamic wall pressures, and the total wall force, base shear and base moment.

  7. Three-dimensional analysis of cavity wall deformation after composite restoration of masticatory teeth.

    Science.gov (United States)

    Manchorova-Veleva, Neshka A

    2011-01-01

    The aim of the present work was to study the size of cavity wall deformation in eight class I and II defects after composite restoration. 1. Creating a geometric model - data on the size of the left maxillary second premolar were obtained from a routine craniofacial scanning of a 20-year-old patient with a 2,5 Dental CT scanner (General Electric), with high resolution and 0.625mm-thin slices. The contour of each of the 33 cross-sections of tooth 25 was delineated using graphics software (CorelDraw 7.0) and transferred to a specialized product for engineering design (SolidWorks Office Premium 2010, SolidWorks Corp. USA). The pulp cavity and periodontal ligament were created in the same manner and were integrated in the premolar body; 2. Generation of a finite element method - the geometric model was exported to specialized software for analysis by the finite element method - COSMOSWorks 2010, which automatically builds a 3D finite elements mesh. Based on the generated model, eight additional models of class I and II cavities with different geometries, adhesive layer and nanofilled composite restorations were constructed. The polymerization shrinkage was modelled by thermal deformation, with a negative temperature difference (cooling), corresponding to the actual volume shrinkage of the composite materials by 2.1%. In models A and B, the maximum cavity wall displacement was small - 0.014 mm and 0.015 mm, respectively. In models Al, B1, C1 and C, the displacement was at the expense of large deformation of the dental tissues. The maximum cavity wall displacements were 0.020 mm, 0.026 mm, 0.020 mm, 0.035 mm, respectively. The least cavity wall displacement was in models A2 and B2 with 0.008 mm and 0.017 mm, respectively. The least displacement resulting from cavity wall deformation is found in patient-friendly class I and II preparations. Preservation of the dental tissues reduces the risk of mechanical pressure on the dentinal lymph and the likelihood of post

  8. Biomechanics Analysis of Combat Sport (Silat) By Using Motion Capture System

    Science.gov (United States)

    Zulhilmi Kaharuddin, Muhammad; Badriah Khairu Razak, Siti; Ikram Kushairi, Muhammad; Syawal Abd. Rahman, Mohamed; An, Wee Chang; Ngali, Z.; Siswanto, W. A.; Salleh, S. M.; Yusup, E. M.

    2017-01-01

    ‘Silat’ is a Malay traditional martial art that is practiced in both amateur and in professional levels. The intensity of the motion spurs the scientific research in biomechanics. The main purpose of this abstract is to present the biomechanics method used in the study of ‘silat’. By using the 3D Depth Camera motion capture system, two subjects are to perform ‘Jurus Satu’ in three repetitions each. One subject is set as the benchmark for the research. The videos are captured and its data is processed using the 3D Depth Camera server system in the form of 16 3D body joint coordinates which then will be transformed into displacement, velocity and acceleration components by using Microsoft excel for data calculation and Matlab software for simulation of the body. The translated data obtained serves as an input to differentiate both subjects’ execution of the ‘Jurus Satu’. Nine primary movements with the addition of five secondary movements are observed visually frame by frame from the simulation obtained to get the exact frame that the movement takes place. Further analysis involves the differentiation of both subjects’ execution by referring to the average mean and standard deviation of joints for each parameter stated. The findings provide useful data for joints kinematic parameters as well as to improve the execution of ‘Jurus Satu’ and to exhibit the process of learning a movement that is relatively unknown by the use of a motion capture system.

  9. Evaluating the Reproducibility of Motion Analysis Scanning of the Spine during Walking

    Directory of Open Access Journals (Sweden)

    Aaron Gipsman

    2014-01-01

    Full Text Available The Formetric 4D dynamic system (Diers International GmbH, Schlangenbad, Germany is a rasterstereography based imaging system designed to evaluate spinal deformity, providing radiation-free imaging of the position, rotation, and shape of the spine during the gait cycle. Purpose. This study was designed to evaluate whether repeated measurements with the Formetric 4D dynamic system would be reproducible with a standard deviation of less than +/− 3 degrees. This study looked at real-time segmental motion, measuring kyphosis, lordosis, trunk length, pelvic, and T4 and L1 vertebral body rotation. Methods. Twenty healthy volunteers each underwent 3 consecutive scans. Measurements for kyphosis, lordosis, trunk length, and rotations of T4, L1, and the pelvis were recorded for each trial. Results. The average standard deviations of same-day repeat measurements were within +/− 3 degrees with a range of 0.51 degrees to 2.3 degrees. Conclusions. The surface topography system calculated reproducible measurements with error ranges comparable to the current gold standard in dynamic spinal motion analysis. Therefore, this technique should be considered of high clinical value for reliably evaluating segmental motion and spinal curvatures and should further be evaluated in the setting of adolescent idiopathic scoliosis.

  10. Simulation-Based Analysis of Ship Motions in Short-Crested Irregular Seas

    Directory of Open Access Journals (Sweden)

    Kıvanç Ali ANIL

    2017-03-01

    Full Text Available Demonstration of the seakeeping calculation results other than polar diagrams and Cartesian plots is important during the initial and detail design stages of naval platforms due to the necessity of numerical simulations (time series data for the design and validation of the systems on board. These time series simulations are called as “real time computer experiments”. Similar simulation algorithms for ship motions and wave elevation are also used by ship-handling simulators for realistic visualization. The goal of this paper is to create a basis for the simulation-based analysis of ship motions and wave elevation for future design and validation studies for both the naval platform itself and the systems on board. The focus of this paper is the clarification of the theoretical background of this process, i.e. all formulations required to create and validate a ship motion and wave surface simulation are given in detail. The results of this study may also be used in ship-handling simulators or helicopter landing on ship simulations.

  11. Quantitative analysis of backbone motion in proteins using MAS solid-state NMR spectroscopy.

    Science.gov (United States)

    Chevelkov, Veniamin; Fink, Uwe; Reif, Bernd

    2009-09-01

    We present a comprehensive analysis of protein dynamics for a micro-crystallin protein in the solid-state. Experimental data include (15)N T (1) relaxation times measured at two different magnetic fields as well as (1)H-(15)N dipole, (15)N CSA cross correlated relaxation rates which are sensitive to the spectral density function J(0) and are thus a measure of T (2) in the solid-state. In addition, global order parameters are included from a (1)H,(15)N dipolar recoupling experiment. The data are analyzed within the framework of the extended model-free Clore-Lipari-Szabo theory. We find slow motional correlation times in the range of 5 and 150 ns. Assuming a wobbling in a cone motion, the amplitude of motion of the respective amide moiety is on the order of 10 degrees for the half-opening angle of the cone in most of the cases. The experiments are demonstrated using a perdeuterated sample of the chicken alpha-spectrin SH3 domain.

  12. Receiver Function Analysis of Strong-motion Stations in Kaohsiung-Pingtung area, Taiwan

    Science.gov (United States)

    Lin, Che-Min; Wen, Kuo-Liang; Kuo, Chun-Hsiang; Huang, Jyun-Yan

    2016-04-01

    The Kaohsiung City and Pingtung County are located in southern Taiwan and bounded on the west side by several active faults. The shallow velocity structure of thick alluvium basin in this area should be delineated to understand the seismic site effect of strong ground motion. Receiver Function (RF) is a conventional technique for studying the structure of the crust and upper mantle beneath the seismometer. But, the RF analysis of high-frequency acceleration seismograms is also proved to be feasible for estimating shallow structures recently. This study applied the RF technique on the Strong-motion records of almost one-hundred TSMIP stations in Kaohsiung-Pingtung area to estimate the shallow shear-wave velocity structures. The averaged RFs of all stations exhibit the obvious variation because of the different geologies and site conditions. After the forward modeling of RFs based on the Genetic Algorithms (GA) searching, the shallow shear-wave velocity structures beneath all the strong-motion stations in the Kaohsiung-Pingtung area were estimated to delineate the iso-depth contour maps of the main formation interfaces and a preliminary shallow 3D velocity model.

  13. Fluid-structure-interaction analysis for welded pipes with flow-accelerated corrosion wall thinning

    Energy Technology Data Exchange (ETDEWEB)

    Sun, L.; Ding, Y., E-mail: lan.sun@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2016-06-15

    The flow-accelerated corrosion (FAC) entrance effect results in enhanced wall thinning immediately downstream of a weld if the weld connects an upstream FAC-resistant material with a downstream less resistant material. The weld regions, especially those with local repairs, are susceptible to cracking due to the high residual stresses induced by fabrication. The combined effects of the FAC entrance effect and high stresses at a weld might compromise the structural integrity of the piping and lead to a failure. Weld degradation by FAC entrance effect has been observed at nuclear and fossil power plants. This paper describes an application using fluid-structure-interaction (FSI) modelling to study the combined effects of FAC wall thinning, weld residual stresses, and in-service loads on welded structures. Simplified cases analyzed were based on CANDU outlet feeder conditions. The analysis includes the flow and mass transfer modelling of the FAC entrance effect using computational fluid dynamics (CFD) and nonlinear structural analyses of the welded structures with wall thinning and an assumed weld residual stress and strain distribution. The FSI analyses were performed using ANSYS Workbench, an integrated platform that enables the coupling of CFD and structural analysis solutions. The obtained results show that the combination of FAC, weld residual stresses, in-service loads (including the internal pressure) and (or) extreme loads could cause high stresses and affect the integrity of the welded pipes. The present work demonstrated that the FSI modelling can be used as an effective approach to assess the integrity of welded structures. (author)

  14. Motion-compensated coding and frame rate up-conversion: models and analysis.

    Science.gov (United States)

    Dar, Yehuda; Bruckstein, Alfred M

    2015-07-01

    Block-based motion estimation (ME) and motion compensation (MC) techniques are widely used in modern video processing algorithms and compression systems. The great variety of video applications and devices results in diverse compression specifications, such as frame rates and bit rates. In this paper, we study the effect of frame rate and compression bit rate on block-based ME and MC as commonly utilized in inter-frame coding and frame rate up-conversion (FRUC). This joint examination yields a theoretical foundation for comparing MC procedures in coding and FRUC. First, the video signal is locally modeled as a noisy translational motion of an image. Then, we theoretically model the motion-compensated prediction of available and absent frames as in coding and FRUC applications, respectively. The theoretic MC-prediction error is studied further and its autocorrelation function is calculated, yielding useful separable-simplifications for the coding application. We argue that a linear relation exists between the variance of the MC-prediction error and temporal distance. While the relevant distance in MC coding is between the predicted and reference frames, MC-FRUC is affected by the distance between the frames available for interpolation. We compare our estimates with experimental results and show that the theory explains qualitatively the empirical behavior. Then, we use the models proposed to analyze a system for improving of video coding at low bit rates, using a spatio-temporal scaling. Although this concept is practically employed in various forms, so far it lacked a theoretical justification. We here harness the proposed MC models and present a comprehensive analysis of the system, to qualitatively predict the experimental results.

  15. Temporal change of photophobic step-up responses of Euglena gracilis investigated through motion analysis

    Science.gov (United States)

    Ozasa, Kazunari; Won, June; Song, Simon; Tamaki, Shun; Ishikawa, Takahiro; Maeda, Mizuo

    2017-01-01

    The adaptation to a strong light is one of the essential characteristics of green algae, yet lacking relatively the information about the photophobic responses of Eukaryotic microalgae. We investigated the photophobic step-up responses of Euglena gracilis over a time course of several hours with alternated repetition of blue-light pulse illumination and spatially patterned blue-light illumination. Four distinctive photophobic motions in response to strong blue light were identified in a trace image analysis, namely on-site rotation, running and tumbling, continuous circular swimming, and unaffected straightforward swimming. The cells cultured in autotrophic conditions under weak light showed mainly the on-site rotation response at the beginning of blue-light illumination, but they acquired more blue-light tolerant responses of running and tumbling, circular swimming, or straightforward swimming. The efficiency of escaping from a blue-light illuminated area improved markedly with the development of these photophobic motions. Time constant of 3.0 h was deduced for the evolution of photophobic responses of E. gracilis. The nutrient-rich metabolic status of the cells resulting from photosynthesis during the experiments, i.e., the accumulation of photosynthesized nutrient products in balance between formation and consumption, was the main factor responsible for the development of photophobic responses. The reduction-oxidation status in and around E. gracilis cells did not affect their photophobic responses significantly, unlike the case of photophobic responses and phototaxis of Chlamydomonas reinhardtii cells. This study shows that the evolution of photophobic motion type of E. gracilis is dominated mainly by the nutrient metabolic status of the cells. The fact suggests that the nutrient-rich cells have a higher threshold for switching the flagellar motion from straightforward swimming to rotation under a strong light. PMID:28234984

  16. Scaling law for bubbles rising near vertical walls

    Science.gov (United States)

    Dabiri, Sadegh; Bhuvankar, Pramod

    2016-06-01

    This paper examines the rising motion of a layer of gas bubbles next to a vertical wall in a liquid in the presence of an upward flow parallel to the wall to help with the understanding of the fluid dynamics in a bubbly upflow in vertical channels. Only the region near the wall is simulated with an average pressure gradient applied to the domain that balances the weight of the liquid phase. The upward flow is created by the rising motion of the bubbles. The bubbles are kept near the wall by the lateral lift force acting on them as a result of rising in the shear layer near the wall. The rise velocity of the bubbles sliding on the wall and the average rise velocity of the liquid depend on three dimensionless parameters, Archimedes number, Ar, Eötvös number, Eo, and the average volume fraction of bubbles on the wall. In the limit of small Eo, bubbles are nearly spherical and the dependency on Eo becomes negligible. In this limit, the scaling of the liquid Reynolds number with Archimedes number and the void fraction is presented. A scaling argument is presented based on viscous dissipation analysis that matches the numerical findings. Viscous dissipation rates are found to be high in a thin film region between the bubble and the wall. A scaling of the viscous dissipation and steady state film thickness between the bubble and the wall with Archimedes number is presented.

  17. Tongue Motion Patterns in Post-Glossectomy and Typical Speakers: A Principal Components Analysis

    Science.gov (United States)

    Stone, Maureen; Langguth, Julie M.; Woo, Jonghye; Chen, Hegang; Prince, Jerry L.

    2014-01-01

    Purpose: In this study, the authors examined changes in tongue motion caused by glossectomy surgery. A speech task that involved subtle changes in tongue-tip positioning (the motion from /i/ to /s/) was measured. The hypothesis was that patients would have limited motion on the tumor (resected) side and would compensate with greater motion on the…

  18. Proper motion survey and kinematic analysis of the ρ Ophiuchi embedded cluster

    Science.gov (United States)

    Ducourant, C.; Teixeira, R.; Krone-Martins, A.; Bontemps, S.; Despois, D.; Galli, P. A. B.; Bouy, H.; Le Campion, J. F.; Rapaport, M.; Cuillandre, J. C.

    2017-01-01

    Context. The ρ Ophiuchi molecular complex and in particular the Lynds L1688 dark cloud is unique in its proximity ( 130 pc), in its richness in young stars and protostars, and in its youth (0.5 Myr). It is certainly one of the best targets currently accessible from the ground to study the early phases of star-formation. Proper motion analysis is a very efficient tool for separating members of clusters from field stars, but very few proper motions are available in the ρ Ophiuchi region since most of the young sources are deeply embedded in dust and gas. Aims: We aim at performing a kinematic census of young stellar objects (YSOs) in the ρ Ophiuchi F core and partially in the E core of the L1688 dark cloud. Methods: We run a proper motion program at the ESO New Technology Telescope (NTT) with the Son of ISAAC (SOFI) instrument over nine years in the near-infrared. We complemented these observations with various public image databases to enlarge the time base of observations and the field of investigation to 0.5° × 0.5°. We derived positions and proper motions for 2213 objects. From these, 607 proper motions were derived from SOFI observations with a 1.8 mas/yr accuracy while the remaining objects were measured only from auxiliary data with a mean precision of about 3 mas/yr. Results: We performed a kinematic analysis of the most accurate proper motions derived in this work, which allowed us to separate cluster members from field stars and to derive the mean properties of the cluster. From the kinematic analysis we derived a list of 68 members and 14 candidate members, comprising 26 new objects with a high membership probability. These new members are generally fainter than the known ones. We measured a mean proper motion of (μαcosδ, μδ) = (-8.2,-24.3) ± 0.8 mas/yr for the L1688 dark cloud. A supervised classification was applied to photometric data of members to allocate a spectral energy distribution (SED) classification to the unclassified members

  19. Rapid analysis of Listeria monocytogenes cell wall teichoic acid carbohydrates by ESI-MS/MS.

    Science.gov (United States)

    Eugster, Marcel R; Loessner, Martin J

    2011-01-01

    We report the application of electrospray ionization (ESI) mass spectrometry for compositional characterization of wall teichoic acids (WTA), a major component of gram-positive bacterial cell walls. Tandem mass spectrometry (ESI-MS/MS) of purified and chemically hydrolyzed monomeric WTA components provided sufficient information to identify WTA monomers and their specific carbohydrate constituents. A lithium matrix was used for ionization of uncharged WTA monomers, and successfully applied to analyze the WTA molecules of four Listeria strains differing in carbohydrate substitution on a conserved polyribitol-phosphate backbone structure. Carbohydrate residues such as N-acetylglucosamine or rhamnose linked to the WTA could directly be identified by ESI-MS/MS, circumventing the need for quantitative analysis by gas chromatography. The presence of a terminal N-acetylglucosamine residue tethered to the ribitol was confirmed using fluorescently labeled wheat-germ agglutinin. In conclusion, the mass spectrometry method described here will greatly facilitate compositional analysis and characterization of teichoic acids and similar macromolecules from diverse bacterial species, and represents a significant advance in the identification of serovar-specific carbohydrates and sugar molecules on bacteria.

  20. Rapid analysis of Listeria monocytogenes cell wall teichoic acid carbohydrates by ESI-MS/MS.

    Directory of Open Access Journals (Sweden)

    Marcel R Eugster

    Full Text Available We report the application of electrospray ionization (ESI mass spectrometry for compositional characterization of wall teichoic acids (WTA, a major component of gram-positive bacterial cell walls. Tandem mass spectrometry (ESI-MS/MS of purified and chemically hydrolyzed monomeric WTA components provided sufficient information to identify WTA monomers and their specific carbohydrate constituents. A lithium matrix was used for ionization of uncharged WTA monomers, and successfully applied to analyze the WTA molecules of four Listeria strains differing in carbohydrate substitution on a conserved polyribitol-phosphate backbone structure. Carbohydrate residues such as N-acetylglucosamine or rhamnose linked to the WTA could directly be identified by ESI-MS/MS, circumventing the need for quantitative analysis by gas chromatography. The presence of a terminal N-acetylglucosamine residue tethered to the ribitol was confirmed using fluorescently labeled wheat-germ agglutinin. In conclusion, the mass spectrometry method described here will greatly facilitate compositional analysis and characterization of teichoic acids and similar macromolecules from diverse bacterial species, and represents a significant advance in the identification of serovar-specific carbohydrates and sugar molecules on bacteria.