WorldWideScience

Sample records for wall motion studies

  1. Tissue Doppler imaging of carotid plaque wall motion: a pilot study

    Directory of Open Access Journals (Sweden)

    Naylor A Ross

    2003-12-01

    Full Text Available Abstract Background Studies suggest the physical and mechanical properties of vessel walls and plaque may be of clinical value in the diagnosis and treatment of cardiovascular atherosclerotic disease. The purpose of this pilot study was to investigate the potential clinical application of ultrasound Tissue Doppler Imaging (TDI of Arterial Wall Motion (AWM and to quantify simple wall motion indices in normal and diseased carotid arteries. Methods 224 normal and diseased carotid arteries (0–100% stenoses were imaged in 126 patients (age 25–88 years, mean 68 ± 11. Longitudinal sections of the carotid bifurcation were imaged using a Philips HDI5000 scanner and L12-5 probe under optimized TDI settings. Temporal and spatial AWMs were analyzed to evaluate the vessel wall displacements and spatial gradients at peak systole averaged over 5 cardiac cycles. Results AWM data were successfully extracted in 91% of cases. Within the carotid bifurcation/plaque region, the maximum wall dilation at peak systole ranged from -100 to 750 microns, mean 335 ± 138 microns. Maximum wall dilation spatial gradients ranged 0–0.49, mean 0.14 ± 0.08. The AWM parameters showed a wide variation and had poor correlation with stenoses severity. Case studies illustrated a variety of pertinent qualitative and quantitative wall motion features related to the biophysics of arterial disease. Conclusion Our clinical experience, using a challenging but realistic imaging protocol, suggests the use of simple quantitative AWM measures may have limitations due to high variability. Despite this, pertinent features of AWM in normal and diseased arteries demonstrate the potential clinical benefit of the biomechanical information provided by TDI.

  2. 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

    Objectives Left ventricular systolic wall motion abnormalities have prognostic value. Whether wall motion detected by serial echocardiographic examinations predicts prognosis in hypertensive patients with left ventricular hypertrophy ( LVH) without clinically recognized atherosclerotic disease ha...

  3. Clustering Of Left Ventricular Wall Motion Patterns

    Science.gov (United States)

    Bjelogrlic, Z.; Jakopin, J.; Gyergyek, L.

    1982-11-01

    A method for detection of wall regions with similar motion was presented. A model based on local direction information was used to measure the left ventricular wall motion from cineangiographic sequence. Three time functions were used to define segmental motion patterns: distance of a ventricular contour segment from the mean contour, the velocity of a segment and its acceleration. Motion patterns were clustered by the UPGMA algorithm and by an algorithm based on K-nearest neighboor classification rule.

  4. Quantification of wall motion and phase of contraction in tomographic gated blood pool studies using length-based Fourier analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kenichi; Bunko, Hisashi; Taki, Junichi; Nambu, Ichiro; Shiire, Yasushi; Tonami, Norihisa; Hisada, Kinichi; Tada, Akira; Kojima, Kazuhkio

    1985-03-01

    Length-based Fourier analysis, a new method for quantification of wall motion and timing of contraction, was applied to tomographic gated blood pool study. Two parameters, percent-length shortening (%LS) and length-based phase were calculated based on the time-length curves from a center to ventricular edges, and compared with the count-based method. In mathematical models for tomographic gated blood pool images, the severity of asynergy was easily determined by length-based method, and the accuracy of the parameters was good. As to the setting of the center, fixed center provided more reliable parameters than the method using movable center, i.e., when a center of gravity was determined in each frame. By length-based Fourier analysis, quantification of wall motion was easily performed, and the initial inward movement caused by the accessory conduction pathway was assessed in patients with Wolff-Parkinson-White syndrome. Length-based approach was considered to be reasonable and effective because the movements of the ventricular edges are essential in tomographic gated blood pool images.

  5. Quantification of wall motion and phase of contraction in tomographic gated blood pool studies using length-based Fourier analysis

    International Nuclear Information System (INIS)

    Nakajima, Kenichi; Bunko, Hisashi; Taki, Junichi; Nambu, Ichiro; Shiire, Yasushi; Tonami, Norihisa; Hisada, Kinichi; Tada, Akira; Kojima, Kazuhiko.

    1985-01-01

    Length-based Fourier analysis, a new method for quantification of wall motion and timing of contraction, was applied to tomographic gated blood pool study. Two parameters, percent-length shortening (%LS) and length-based phase were calculated based on the time-length curves from a center to ventricular edges, and compared with the count-based method. In mathematical models for tomographic gated blood pool images, the severity of asynergy was easily determined by length-based method, and the accuracy of the parameters was good. As to the setting of the center, fixed center provided more reliable parameters than the method using movable center, i.e., when a center of gravity was determined in each frame. By length-based Fourier analysis, quantification of wall motion was easily performed, and the initial inward movement caused by the accessory conduction pathway was assessed in patients with Wolff-Parkinson-White syndrome. Length-based approach was considered to be reasonable and effective because the movements of the ventricular edges are essential in tomographic gated blood pool images. (author)

  6. Wall motion abnormality of myocardial infarction

    International Nuclear Information System (INIS)

    Hayashi, Senji; Tsuda, Takashi; Ojima, Kenji

    1984-01-01

    By use of the gated blood pool scan, we divided the left ventricular LAO 45 image into 8 sections with the center of the volume as the basal point, and devised a method of quantitative evaluation of the regional wall motion from 2 aspects: 1) wall movement and 2) phase abnormality. To evaluate the wall movement, we obtained the following indeces from count curves of each section: 1) EF1=(end-diastolic count-end-systolic count)/ end-diastolic count, 2) EF2=(maximum count-minimum count)/maximum count, and 3) the difference of the two (EF2-EF1). As indeces of the phase abnormality, the mean value of phases of the pixels (phase characteristics) and the standard deviation (variation) of each section were calculated. Furthermore, the phase delay of each section was calculated as the difference from the earliest phase value of the 8 sections. Control values and standard deviation were obtained from 8 healthy controls. By this method, we analyzed 20 patients with old myocardial infarction. And following results were obtained: 1. Applying this method, we could evaluate the regional wall motion of the left ventricle more precisely, and we considered it would be useful clinically. 2. The abnormal regional wall motion of old myocardial infarction were classified into 4 typical forms as follows: 1) the wall movement decreased extremely. 2) the wall movement decreased, but no phase delay recognized. 3) the wall movement did not decrease, but phase delay was recognized. 4) the wall movement decreased, and phase delay was recognized. (author)

  7. Noninvasive assessment of right ventricular wall motion by radionuclide cardioangiography

    International Nuclear Information System (INIS)

    Nishimura, Tsunehiko; Uehara, Toshiisa; Naito, Hiroaki; Hayashida, Kohei; Kozuka, Takahiro

    1981-01-01

    Radionuclide cardioangiography is a useful method to evaluate the left ventricular wall motion in various heart diseases. It has been also attempted to assess the right ventricular wall motion simultaneously by radionuclide method. In this study, using the combination of first-pass (RAO 30 0 ) and multi-gate (LAO 40 0 ) method, the site of right vetricle was classified in five. (1 inflow, 2 sinus, 3 outflow, 4 septal, 5 lateral) and the degree of wall motion was classified in four stages (dyskinesis, akinesis, hypokinesis, normal) according to the AHA committee report. These methods were applied clinically to forty-eight patients with various heart diseases. In the cases with right ventricular pressure or volume overload such as COLD, pulmonary infarction, the right ventricle was dilated and the wall motion was reduced in all portions. Especially, in the cases with right ventricular infarction, the right ventricular wall motion was reduced in the infarcted area. The findings of radionuclide method were in good agreement with those of contrast right ventriculography or echocardiography. In conclusion, radionuclide cardioangiography is a useful and noninvasive method to assess not only the left but also the right ventricular wall motion. (author)

  8. 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.

  9. 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).

  10. Fractional Brownian motion with a reflecting wall

    Science.gov (United States)

    Wada, Alexander H. O.; Vojta, Thomas

    2018-02-01

    Fractional Brownian motion, a stochastic process with long-time correlations between its increments, is a prototypical model for anomalous diffusion. We analyze fractional Brownian motion in the presence of a reflecting wall by means of Monte Carlo simulations. Whereas the mean-square displacement of the particle shows the expected anomalous diffusion behavior ˜tα , the interplay between the geometric confinement and the long-time memory leads to a highly non-Gaussian probability density function with a power-law singularity at the barrier. In the superdiffusive case α >1 , the particles accumulate at the barrier leading to a divergence of the probability density. For subdiffusion α implications of these findings, in particular, for applications that are dominated by rare events.

  11. 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....

  12. Magnetization reversal in ferromagnetic spirals via domain wall motion

    Science.gov (United States)

    Schumm, Ryan D.; Kunz, Andrew

    2016-11-01

    Domain wall dynamics have been investigated in a variety of ferromagnetic nanostructures for potential applications in logic, sensing, and recording. We present a combination of analytic and simulated results describing the reliable field driven motion of a domain wall through the arms of a ferromagnetic spiral nanowire. The spiral geometry is capable of taking advantage of the benefits of both straight and circular wires. Measurements of the in-plane components of the spirals' magnetization can be used to determine the angular location of the domain wall, impacting the magnetoresistive applications dependent on the domain wall location. The spirals' magnetization components are found to depend on the spiral parameters: the initial radius and spacing between spiral arms, along with the domain wall location. The magnetization is independent of the parameters of the rotating field used to move the domain wall, and therefore the model is valid for current induced domain wall motion as well. The speed of the domain wall is found to depend on the frequency of the rotating driving field, and the domain wall speeds can be reliably varied over several orders of magnitude. We further demonstrate a technique capable of injecting multiple domain walls and show the reliable and unidirectional motion of domain walls through the arms of the spiral.

  13. Cartan frames for heart wall fiber motion

    NARCIS (Netherlands)

    Samari, Babak; Aumentado-Armstrong, Tristan; Strijkers, Gustav J.; Froeling, Martijn; Siddiqi, Kaleem

    2017-01-01

    Current understanding of heart wall fiber geometry is based on ex vivo static data obtained through diffusion imaging or histology. Thus, little is known about the manner in which fibers rotate as the heart beats. Yet, the geometric organization of moving fibers in the heart wall is key to its

  14. Evaluation of segmental left ventricular wall motion by equilibrium gated radionuclide ventriculography.

    Science.gov (United States)

    Van Nostrand, D; Janowitz, W R; Holmes, D R; Cohen, H A

    1979-01-01

    The ability of equilibrium gated radionuclide ventriculography to detect segmental left ventricular (LV) wall motion abnormalities was determined in 26 patients undergoing cardiac catheterization. Multiple gated studies obtained in 30 degrees right anterior oblique and 45 degrees left anterior oblique projections, played back in a movie format, were compared to the corresponding LV ventriculograms. The LV wall in the two projections was divided into eight segments. Each segment was graded as normal, hypokinetic, akinetic, dyskinetic, or indeterminate. Thirteen percent of the segments in the gated images were indeterminate; 24 out of 27 of these were proximal or distal inferior wall segments. There was exact agreement in 86% of the remaining segments. The sensitivity of the radionuclide technique for detecting normal versus any abnormal wall motion was 71%, with a specificity of 99%. Equilibrium gated ventriculography is an excellent noninvasive technique for evaluating segmental LV wall motion. It is least reliable in assessing the proximal inferior wall and interventricular septum.

  15. Reasons for the lack of benefit of immediate angioplasty during recombinant tissue plasminogen activator therapy for acute myocardial infarction: a regional wall motion analysis. European Cooperative Study Group

    NARCIS (Netherlands)

    Arnold, A. E.; Serruys, P. W.; Rutsch, W.; Simoons, M. L.; de Bono, D. P.; Tijssen, J. G.; Lubsen, J.; Verstraete, M.

    1991-01-01

    Regional ventricular wall motion analysis utilizing three different methods was performed on predischarge left ventriculograms from 291 of 367 patients enrolled in a randomized trial of single chain recombinant tissue-type plasminogen activator (rt-PA), aspirin and heparin with and without immediate

  16. Segmental wall motion abnormalities in dilated cardiomyopathy: hemodynamic characteristics and comparison with thallium-201 myocardial scintigraphy

    International Nuclear Information System (INIS)

    Yamaguchi, S.; Tsuiki, K.; Hayasaka, M.; Yasui, S.

    1987-01-01

    This study assessed the hemodynamic characteristics of segmental wall motion abnormality of the left ventricle in patients with dilated cardiomyopathy (DCM) and its relation to the thallium-201 (TI-201) myocardial scintigraphy (MPI). Left ventriculograms and MPI in 23 patients were analyzed by the use of quantitative indexes of regional wall motion and TI-201 uptake based on a mean and a standard deviation of 13 normal subjects. Relative normokinesis in our definition was more frequently seen in the inferior wall than in the anterior wall (p less than 0.01). In contrast, severe asynergy was more often seen in the anterior wall than in the inferior wall (p less than 0.01). There were 11 patients who had relative normokinesis and asynergy together. By means of the index of wall motion, the DCM patients were divided into two groups, one with segmental wall motion abnormality (SWMA) and another with diffuse wall motion abnormality (DWMA). The DWMA group had higher left ventricular end-diastolic pressures (p less than 0.05) and the tendency of large left ventricular end-diastolic volumes than the SWMA group. There was a rough correlation (r = 0.58) between the quantitative indexes of TI-201 uptake and wall motion at the same region of the left ventricle. Thus, the nonuniformity of the left ventricular wall motion was recognized in the patients with DCM and more increased preload was shown in the patients with DWMA than in the group with SWMA. Further, the regional asynergy may be related to the localized fibrosis within the left ventricle in DCM, considering the result that the worse TI-201 uptake was roughly accompanied by the more severe asynergy

  17. Rashba spin–orbit coupling effects on a current-induced domain wall motion

    International Nuclear Information System (INIS)

    Ryu, Jisu; Seo, Soo-Man; Lee, Kyung-Jin; Lee, Hyun-Woo

    2012-01-01

    A current-induced domain wall motion in magnetic nanowires with a strong structural inversion asymmetry [I.M. Miron, T. Moore, H. Szambolics, L.D. Buda-Prejbeanu, S. Auffret, B. Rodmacq, S. Pizzini, J. Vogel, M. Bonfim, A. Schuhl, G. Gaudin, Nat. Mat. 10 (2011) 419] seems to have novel features such as the domain wall motion along the current direction or the delay of the onset of the Walker breakdown. In such a highly asymmetric system, the Rashba spin–orbit coupling (RSOC) may affect a domain wall motion. We studied theoretically the RSOC effects on a domain wall motion and found that the RSOC, indeed, can induce the domain wall motion along the current direction in certain situations. It also delays the Walker breakdown and for a strong RSOC, the Walker breakdown does not occur at all. The RSOC effects are sensitive to the magnetic anisotropy of nanowires and also to the ratio between the Gilbert damping parameter α and the non-adiabaticity parameter β. - Highlights: ► Effects of Rashba spin–orbit coupling on a domain wall motion is calculated. ► The effects depend highly on the anisotropy of a magnetic system. ► It modifies the wall velocity for the system with a perpendicular magnetic anisotropy. ► The modified velocity can be along the current direction in certain situations. ► Rashba spin–orbit coupling also hinders the onset of the Walker breakdown.

  18. Domain wall motion in ferromagnetic systems with perpendicular magnetization

    International Nuclear Information System (INIS)

    Szambolics, H.; Toussaint, J.-Ch.; Marty, A.; Miron, I.M.; Buda-Prejbeanu, L.D.

    2009-01-01

    Although we lack clear experimental evidence, apparently out-of-plane magnetized systems are better suited for spintronic applications than the in-plane magnetized ones, mainly due to the smaller current densities required for achieving domain wall motion. [Co/Pt] multilayers belong to the first category of materials, the out-of-plane magnetization orientation arising from the strong perpendicular magnetocrystalline anisotropy. If the magnetization arranges itself out-of-plane narrow Bloch walls occur. In the present paper, both field and current-driven domain wall motion have been investigated for this system, using micromagnetic simulations. Three types of geometries have been taken into account: bulk, thin film and wire, and for all of them a full comparison is done between the effect of the applied field and injected current. The reduction of the system's dimension induces the decrease of the critical field and the critical current, but it does not influence the domain wall displacement mechanism.

  19. Imaging of left ventricular wall motion via venous DSA

    International Nuclear Information System (INIS)

    Witte, G.; Roediger, W.; Buecheler, E.; Hamburg Univ.

    1986-01-01

    Until now, angiographical and nuclear medicine examination techniques for imaging left ventricular wall motion have been presenting with difficulties endemic to the methods themselves. For the first time in cardiological diagnostics, digital subtraction angiography (DSA) makes it possible to perform a fairly non-invasive examination with good spatial and temporal resolution. Functional analytic evaluation, however, still demands time-consuming, complicated post-processing. In this article we introduce a method that uses an additive window technique for the immediate generation of wall motion images. (orig.) [de

  20. Domain wall motion in magnetically frustrated nanorings

    Science.gov (United States)

    Lubarda, M. V.; Escobar, M. A.; Li, S.; Chang, R.; Fullerton, E. E.; Lomakin, V.

    2012-06-01

    We describe a magnetically frustrated nanoring (MFNR) configuration which is formed by introducing antiferromagnetic coupling across an interface orthogonal to the ring's circumferential direction. Such structures have the unique characteristic that only one itinerant domain wall (DW) can exist in the ring, which does not need to be nucleated or injected into the structure and can never escape making it analogous to a magnetic Möbius strip. Numerical simulations show that the DW in a MFNR can be driven consecutively around the ring with a prescribed cyclicity, and that the frequency of revolutions can be controlled by the applied field. The energy landscapes can be controlled to be flat allowing for low fields of operation or to have a barrier for thermal stability. Potential logic and memory applications of MFNRs are considered and discussed.

  1. Detection of cardiac wall motion defects with combined amplitude/phase analysis

    International Nuclear Information System (INIS)

    Bacharach, S.L.; Green, M.V.; Bonow, R.O.; Pace, L.; Brunetti, A.; Larson, S.M.

    1985-01-01

    Fourier phase images have been used with some success to detect and quantify left ventricular (LV) wall motion defects. In abnormal regions of the LV, wall motion asynchronies often cause the time activity curve (TAC) to be shifted in phase. Such regional shifts are detected by analysis of the distribution function of phase values over the LV. However, not all wall motion defects result in detectable regional phase abnormalities. Such abnormalities may cause a reduction in the magnitude of contraction (and hence TAC amplitude) without any appreciable change in TAC shape(and hence phase). In an attempt to improve the sensitivity of the Fourier phase method for the detection of wall motion defects the authors analyzed the distribution function of Fourier amplitude as well as phase. 26 individuals with normal cardiac function and no history of cardiac disease served as controls. The goal was to detect and quantify wall motion as compared to the consensus of 3 independent observers viewing the scintigraphic cines. 26 subjects with coronary artery disease and mild wall motion defects (22 with normal EF) were studied ate rest. They found that analysis of the skew of thew amplitude distribution function improved the sensitivity for the detection of wall motion abnormalities at rest in the group from 65% to 85% (17/26 detected by phase alone, 22/26 by combined phase and amplitude analysis) while retaining a 0 false positive rate in the normal group. The authors conclude that analysis of Fourier amplitude distribution functions can significantly increase the sensitivity of phase imaging for detection of wall motion abnormalities

  2. Clinical evaluation of segmental wall motion by radionuclide cardioangiography in the patients with myocardial infarction

    International Nuclear Information System (INIS)

    Nishimura, Tsunehiko; Uehara, Toshiisa; Kozuka, Takahiro

    1980-01-01

    To detect segmental wall motion of left ventricle is useful to identify the size and location of infarcted area in coronary arteries diseases. In this study, segmental wall motion by radionuclide cardioangiography were evaluated to compare with contrast left ventriculography in fifty patients of myocardial infarction. Segmental wall motion in RAO position by first pass method, in LAO position by multi-gated method were evaluated using an Anger camera and on-line minicomputer system by following methods; ED, ES images, sequential images, edge display, regional ejection fraction and movie imaging system (MIS). The percent agreements of segmental wall motion by RI and LVG were 84% in 350 segments of 50 cases. In all segments, segments 4, 6, 7 were better agreements than other segments. For the degree of wall motion, skinesis and dyskinesis were good agreements in both methods, while hypokinesia was slightly poor agreement (62%). On the other hand, the size of infarction, that is, percent thallium defect area was good correlated with radionuclide left ventricular ejection fraction (r = -0.855 in anterior infarction, r = -0.646 in inferior infarction). From these data, wall motion was thought to be closely related with left ventricular function, therefore, regional ejection fraction in seven areas in left ventricular image was developed and compared with segmental wall motion in left ventriculogram according to the classification of A.H.A. Comittee Report. The value of regional ejection fraction is 0.29, 0.40, 0.60 in akinesis, hypokinesis and normal. In conclusion, radionuclide cardioangiography is useful in the detection of abnormal segmental wall motion as noninvasive methods. (author)

  3. 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.

  4. Domain-walls motion in glass-coated CoFeSiB amorphous microwires

    Energy Technology Data Exchange (ETDEWEB)

    Antonov, A.S. E-mail: as.antonov@mtu-net.ru; Buznikov, N.A.; Granovsky, A.B.; Joura, A.V.; Rakhmanov, A.L.; Yakunin, A.M

    2002-08-01

    A method for observation of domain-walls motion in amorphous microwires with circular magnetic anisotropy is proposed. Using the method, the magnetization reversal of glass-coated Co-based microwires induced by current pulses of high amplitude is studied. The magnetization reversal is shown to occur due to the nucleation of the domain walls at the sample ends and their subsequent motion along the microwire. The dependencies of the domain-wall velocity on the current pulse amplitude and a longitudinal DC magnetic field are measured. A model describing main features of experimental data is presented.

  5. Domain-walls motion in glass-coated CoFeSiB amorphous microwires

    International Nuclear Information System (INIS)

    Antonov, A.S.; Buznikov, N.A.; Granovsky, A.B.; Joura, A.V.; Rakhmanov, A.L.; Yakunin, A.M.

    2002-01-01

    A method for observation of domain-walls motion in amorphous microwires with circular magnetic anisotropy is proposed. Using the method, the magnetization reversal of glass-coated Co-based microwires induced by current pulses of high amplitude is studied. The magnetization reversal is shown to occur due to the nucleation of the domain walls at the sample ends and their subsequent motion along the microwire. The dependencies of the domain-wall velocity on the current pulse amplitude and a longitudinal DC magnetic field are measured. A model describing main features of experimental data is presented

  6. Incremental value of regional wall motion analysis immediately after exercise for the detection of single-vessel coronary artery disease. Study by separate acquisition, dual-isotope ECG-gated single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Yoda, Shunichi; Sato, Yuichi; Matsumoto, Naoya; Tani, Shigemasa; Takayama, Tadateru; Uchiyama, Takahisa; Saito, Satoshi

    2005-01-01

    Although the detection of wall motion abnormalities gives incremental value to myocardial perfusion single-photon emission computed tomography (SPECT) in the diagnosis of extensive coronary artery disease (CAD) and high-grade single-vessel CAD, whether or not it is useful in the diagnosis of mild, single-vessel CAD has not been studied previously. Separate acquisition, dual isotope electrocardiogram (ECG)-gated SPECT was performed in 97 patients with a low likelihood of CAD (Group 1) and 46 patients with single-vessel CAD (Group 2). Mild CAD was defined by stenosis of 50-75% (Group 2a, n=22) and moderate to severe CAD was defined by stenosis ≥76% (Group 2b, n=24). Myocardial perfusion and wall motion were graded by a 5 point-scale, 20-segment model. The sensitivity of myocardial perfusion alone was 50% for Group 2a, 83% for Group 2b and 67% for Group 2 as a whole. The overall specificity was 90%. When the wall motion analysis was combined, the sensitivity was increased to 82% in Group 2a and 92% in Group 2b. The ability to detect a wall motion abnormality immediately after exercise gives incremental diagnostic value to myocardial perfusion SPECT in the identification of mild, single-vessel CAD. (author)

  7. Geometric Relations for CYLEX Test Tube-Wall Motion

    Science.gov (United States)

    Hill, Larry

    2015-06-01

    The CYLinder EXpansion (CYLEX) test is a (precision, instrumented, high-purity annealed copper) pipe bomb. Its essential measured quantities are detonation speed and tube-wall motion. Its main purpose is to calibrate detonation product equations of state (EOS) by measuring how product fluid pushes metal. In its full complexity, CYLEX is an integral test, for which EOS calibration requires the entire system to be computationally modeled and compared to salient data. Stripped to its essence, CYLEX is a non-integral test for which one may perform the inverse problem, to infer the EOS directly from data. CYLEX analysis can be simplified by the fact that the test constituents achieve a steady traveling wave structure; this allows derivation of several useful geometric relationships regarding tube wall motion. The first such treatment was by G.I. Taylor. Although his analysis was limited to small wall deflection angles, he asserted that the results remain valid for arbitrary ones. I confirm this attribute and present additional useful relationships. In the past decade, CYLEX wall-motion instrumentation has migrated almost entirely from streak camera to PDV, yet discrepancies remain between the two methods. I further present geometric relationships that shed light on this issue. Work supported by the U.S. DOE.

  8. 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

    that were screened for inclusion into the DIAMOND-CHF and DIAMOND-MI trials were reevaluated by an external expert echocardiographer. WMI was calculated using the 16-segment LV model. RESULTS: The external echocardiographer systematically found lower values of WMI than the core laboratory. The average...... difference in WMI was 0.18 (SD: 0.33) in the DIAMOND-CHF trial and 0.09 (SD: 0.33) in the DIAMOND-MI trial. The difference in WMI exceeded 0.33 in 34% of the patients in both trials. The cutoff value for inclusion into the DIAMOND trials was WMI ... 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...

  9. Unidirectional Magnon-Driven Domain Wall Motion due to Interfacial Dzyaloshinskii-Moriya Interaction

    KAUST Repository

    Lee, Seo-Won

    2018-03-28

    We theoretically study magnon-driven motion of a tranverse domain wall in the presence of interfacial Dzyaloshinskii-Moriya interaction (DMI). Contrary to previous studies, the domain wall moves along the same direction regardless of the magnon-flow direction. Our symmetry analysis reveals that the odd order DMI contributions to the domain wall velocity are independent of the magnon-flow direction. Corresponding DMI-induced asymmetric transitions from a spin-wave state to another give rise to a large momentum transfer to the domain wall without nonreciprocity and much reflection. This counterintuitive unidirectional motion occurs not only for a spin wave with a single wavevector but also for thermal magnons with distributed wavevectors.

  10. Unidirectional Magnon-Driven Domain Wall Motion due to Interfacial Dzyaloshinskii-Moriya Interaction

    KAUST Repository

    Lee, Seo-Won; Kim, Kyoung-Whan; Moon, Jung-Hwan; Go, Gyungchoon; Manchon, Aurelien; Lee, Hyun-Woo; Everschor-Sitte, Karin; Lee, Kyung-Jin

    2018-01-01

    We theoretically study magnon-driven motion of a tranverse domain wall in the presence of interfacial Dzyaloshinskii-Moriya interaction (DMI). Contrary to previous studies, the domain wall moves along the same direction regardless of the magnon-flow direction. Our symmetry analysis reveals that the odd order DMI contributions to the domain wall velocity are independent of the magnon-flow direction. Corresponding DMI-induced asymmetric transitions from a spin-wave state to another give rise to a large momentum transfer to the domain wall without nonreciprocity and much reflection. This counterintuitive unidirectional motion occurs not only for a spin wave with a single wavevector but also for thermal magnons with distributed wavevectors.

  11. Influence of temperature on current-induced domain wall motion and its Walker breakdown

    International Nuclear Information System (INIS)

    Fan, Lvchao; Hu, Jingguo; Su, Yuanchang; Zhu, Jinrong

    2016-01-01

    The current-driven domain wall propagation along a thin ferromagnetic strip with thermal field is studied by means of micromagnetic simulations. The results show that the velocity of domain wall is almost independent of temperature until Walker breakdown happened. However the thermal field can suppress Walker breakdown and makes domain wall move faster. Further analysis indicates that the thermal field tends to keep the out-of-plane magnetic moment of the domain wall stay in high value, which can promote domain wall motion and suppress the Walker breakdown by breaking the period of domain wall transformation. - Highlights: • Influences of temperature on the displacement and the velocity of DW are shown. • The suppression of Walker breakdown by temperature is given. • The reason for suppressing Walker breakdown is analyzed. • The breaking transformation period of Walker breakdown by temperature is given.

  12. Value of gated SPECT in the analysis of regional wall motion of the interventricular septum after coronary artery bypass grafting

    International Nuclear Information System (INIS)

    Giubbini, Raffaele; Rossini, Pierluigi; Bertagna, Francesco; Bosio, Giovanni; Paghera, Barbara; Pizzocaro, Claudio; Canclini, Silvana; Terzi, Arturo; Germano, Guido

    2004-01-01

    The aim of this study was the evaluation of septal wall motion, perfusion and wall thickening after CABG in two groups of consecutive patients, one with grafted left anterior coronary artery and no history of myocardial infarction, and the other with previous anteroseptal myocardial infarction and impaired septal motion before surgery. The issue addressed was the ability of gated SPECT to differentiate between true paradoxical septal motion, characterised by paradoxical wall motion, depressed ejection fraction (EF), poor viability and compromised wall thickening, and pseudo-paradoxical motion, characterised by abnormal wall motion and regional EF but preserved perfusion and wall thickening. One hundred and thirty-two patients with previous anterior myocardial infarction, 82 patients with left anterior descending coronary disease and no history of myocardial infarction and 27 normal subjects underwent rest gated SPECT after 99m Tc-sestamibi injection, according to the standard QGS protocol. Quantitative regional EF, regional perfusion, regional wall motion and regional wall thickening were determined using a 20-segment model. Despite the presence of similar regional wall motion impairment in patients with and patients without septal infarction, in terms of regional EF (2.5%±3% vs 1.9%±4.9% p=NS) and inward septal motion (3±4.9 mm vs 2.3±6.1 mm p=NS), significant differences were observed in both perfusion (74.7%±6.2% vs 63.3%±13%, p>0.0001) and regional wall thickening (17.2%±7.4% vs 12.6%±7.2%, p>0.0001). Gated SPECT with perfusion tracers can reliably differentiate pseudo-paradoxical from true paradoxical septal motion in patients with previous CABG, and it may be the method of choice for evaluating left ventricular performance in this patient population. (orig.)

  13. Value of gated SPECT in the analysis of regional wall motion of the interventricular septum after coronary artery bypass grafting.

    Science.gov (United States)

    Giubbini, Raffaele; Rossini, Pierluigi; Bertagna, Francesco; Bosio, Giovanni; Paghera, Barbara; Pizzocaro, Claudio; Canclini, Silvana; Terzi, Arturo; Germano, Guido

    2004-10-01

    The aim of this study was the evaluation of septal wall motion, perfusion and wall thickening after CABG in two groups of consecutive patients, one with grafted left anterior coronary artery and no history of myocardial infarction, and the other with previous anteroseptal myocardial infarction and impaired septal motion before surgery. The issue addressed was the ability of gated SPECT to differentiate between true paradoxical septal motion, characterised by paradoxical wall motion, depressed ejection fraction (EF), poor viability and compromised wall thickening, and pseudo-paradoxical motion, characterised by abnormal wall motion and regional EF but preserved perfusion and wall thickening. One hundred and thirty-two patients with previous anterior myocardial infarction, 82 patients with left anterior descending coronary disease and no history of myocardial infarction and 27 normal subjects underwent rest gated SPECT after 99mTc-sestamibi injection, according to the standard QGS protocol. Quantitative regional EF, regional perfusion, regional wall motion and regional wall thickening were determined using a 20-segment model. Despite the presence of similar regional wall motion impairment in patients with and patients without septal infarction, in terms of regional EF (2.5%+/-3% vs 1.9%+/-4.9% p=NS) and inward septal motion (3+/-4.9 mm vs 2.3+/-6.1 mm p=NS), significant differences were observed in both perfusion (74.7%+/-6.2% vs 63.3%+/-13%, p>0.0001) and regional wall thickening (17.2%+/-7.4% vs 12.6%+/-7.2%, p>0.0001). Gated SPECT with perfusion tracers can reliably differentiate pseudo-paradoxical from true paradoxical septal motion in patients with previous CABG, and it may be the method of choice for evaluating left ventricular performance in this patient population.

  14. Value of gated SPECT in the analysis of regional wall motion of the interventricular septum after coronary artery bypass grafting

    Energy Technology Data Exchange (ETDEWEB)

    Giubbini, Raffaele; Rossini, Pierluigi; Bertagna, Francesco; Bosio, Giovanni; Paghera, Barbara; Pizzocaro, Claudio; Canclini, Silvana; Terzi, Arturo [Spedali Civili di Brescia, Department of Nuclear Medicine, Brescia (Italy); Germano, Guido [Cedars-Sinai Medical Center, Artificial Intelligence Program, Department of Medicine, Los Angeles, CA (United States)

    2004-10-01

    The aim of this study was the evaluation of septal wall motion, perfusion and wall thickening after CABG in two groups of consecutive patients, one with grafted left anterior coronary artery and no history of myocardial infarction, and the other with previous anteroseptal myocardial infarction and impaired septal motion before surgery. The issue addressed was the ability of gated SPECT to differentiate between true paradoxical septal motion, characterised by paradoxical wall motion, depressed ejection fraction (EF), poor viability and compromised wall thickening, and pseudo-paradoxical motion, characterised by abnormal wall motion and regional EF but preserved perfusion and wall thickening. One hundred and thirty-two patients with previous anterior myocardial infarction, 82 patients with left anterior descending coronary disease and no history of myocardial infarction and 27 normal subjects underwent rest gated SPECT after {sup 99m}Tc-sestamibi injection, according to the standard QGS protocol. Quantitative regional EF, regional perfusion, regional wall motion and regional wall thickening were determined using a 20-segment model. Despite the presence of similar regional wall motion impairment in patients with and patients without septal infarction, in terms of regional EF (2.5%{+-}3% vs 1.9%{+-}4.9% p=NS) and inward septal motion (3{+-}4.9 mm vs 2.3{+-}6.1 mm p=NS), significant differences were observed in both perfusion (74.7%{+-}6.2% vs 63.3%{+-}13%, p>0.0001) and regional wall thickening (17.2%{+-}7.4% vs 12.6%{+-}7.2%, p>0.0001). Gated SPECT with perfusion tracers can reliably differentiate pseudo-paradoxical from true paradoxical septal motion in patients with previous CABG, and it may be the method of choice for evaluating left ventricular performance in this patient population. (orig.)

  15. 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.

  16. Geometric Control Over the Motion of Magnetic Domain Walls

    International Nuclear Information System (INIS)

    N.A. Sinitsyn; V.V. Dobrovitski; S. urazhdin; Avadh Saxena

    2008-01-01

    We propose a method that enables a precise control of magnetic patterns and relies only on the fundamental properties of the wire as well as on the choice of the path in the controlled parameter space but not on the rate of motion along this path. Possible experimental realizations of this mechanism are discussed. In particular, we show that the domain walls in magnetic nanowires can be translated by rotation of the magnetic easy axis or by applying pulses of magnetic field directed transverse to the magnetic easy axis

  17. 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.

  18. Clinical significance of exercise-induced left ventricular wall motion abnormality occurring at a low heart rate

    International Nuclear Information System (INIS)

    Kimchi, A.; Rozanski, A.; Fletcher, C.; Maddahi, J.; Swan, H.J.; Berman, D.S.

    1987-01-01

    We studied the relationship between the heart rate at the time of onset of exercise-induced wall motion abnormality and the severity of coronary artery disease in 89 patients who underwent exercise equilibrium radionuclide ventriculography as part of their evaluation for coronary artery disease. Segmental wall motion was scored with a five-point system (3 = normal; -1 = dyskinesis); a decrease of one score defined the onset of wall motion abnormality. The onset of wall motion abnormality at less than or equal to 70% of maximal predicted heart rate had 100% predictive accuracy for coronary artery disease and higher sensitivity than the onset of ischemic ST segment depression at similar heart rate during exercise: 36% (25 of 69 patients with coronary disease) vs 19% (13 of 69 patients), p = 0.01. Wall motion abnormality occurring at less than or equal to 70% of maximal predicted heart rate was present in 49% of patients (23 of 47) with critical stenosis (greater than or equal to 90% luminal diameter narrowing), and in only 5% of patients (2 of 42) without such severe stenosis, p less than 0.001. The sensitivity of exercise-induced wall motion abnormality occurring at a low heart rate for the presence of severe coronary artery disease was similar to that of a deterioration in wall motion by more than two scores during exercise (49% vs 53%) or an absolute decrease of greater than or equal to 5% in exercise left ventricular ejection fraction (49% vs 45%)

  19. Minimization of Ohmic Losses for Domain Wall Motion in a Ferromagnetic Nanowire

    Science.gov (United States)

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

    2010-11-01

    We study current-induced domain-wall motion in a narrow ferromagnetic wire. We propose a way to move domain walls with a resonant time-dependent current which dramatically decreases the Ohmic losses in the wire and allows driving of the domain wall with higher speed without burning the wire. For any domain-wall velocity we find the time dependence of the current needed to minimize the Ohmic losses. Below a critical domain-wall velocity specified by the parameters of the wire the minimal Ohmic losses are achieved by dc current. Furthermore, we identify the wire parameters for which the losses reduction from its dc value is the most dramatic.

  20. Minimization of Ohmic losses for domain wall motion in ferromagnetic nanowires

    Science.gov (United States)

    Abanov, Artem; Tretiakov, Oleg; Liu, Yang

    2011-03-01

    We study current-induced domain-wall motion in a narrow ferromagnetic wire. We propose a way to move domain walls with a resonant time-dependent current which dramatically decreases the Ohmic losses in the wire and allows driving of the domain wall with higher speed without burning the wire. For any domain wall velocity we find the time-dependence of the current needed to minimize the Ohmic losses. Below a critical domain-wall velocity specified by the parameters of the wire the minimal Ohmic losses are achieved by dc current. Furthermore, we identify the wire parameters for which the losses reduction from its dc value is the most dramatic. This work was supported by the NSF Grant No. 0757992 and Welch Foundation (A-1678).

  1. Changes in sitting posture induce multiplanar changes in chest wall shape and motion with breathing.

    Science.gov (United States)

    Lee, Linda-Joy; Chang, Angela T; Coppieters, Michel W; Hodges, Paul W

    2010-03-31

    This study examined the effect of sitting posture on regional chest wall shape in three dimensions, chest wall motion (measured with electromagnetic motion analysis system), and relative contributions of the ribcage and abdomen to tidal volume (%RC/V(t)) (measured with inductance plethysmography) in 7 healthy volunteers. In seven seated postures, increased dead space breathing automatically increased V(t) (to 1.5 V(t)) to match volume between conditions and study the effects of posture independent of volume changes. %RC/V(t) (pplane changes in sitting posture alter three-dimensional ribcage configuration and chest wall kinematics during breathing, while maintaining constant respiratory function. Copyright 2010 Elsevier B.V. All rights reserved.

  2. Reliable 5-min real-time MR technique for left-ventricular-wall motion analysis

    International Nuclear Information System (INIS)

    Katoh, Marcus; Spuentrup, Elmar; Guenther, Rolf W.; Buecker, Arno; Kuehl, Harald P.; Lipke, Claudia S.A.

    2007-01-01

    The aim of this study was to investigate the value of a real-time magnetic resonance imaging (MRI) approach for the assessment of left-ventricular-wall motion in patients with insufficient transthoracic echocardiography in terms of accuracy and temporal expenditure. Twenty-five consecutive patients were examined on a 1.5-Tesla whole-body MR system (ACS-NT, Philips Medical Systems, Best, NL) using a real-time and ECG-gated (the current gold standard) steady-state free-precession (SSFP) sequence. Wall motion was analyzed by three observers by consensus interpretation. In addition, the preparation, scanning, and overall examination times were measured. The assessment of the wall motion demonstrated a close agreement between the two modalities resulting in a mean κ coefficient of 0.8. At the same time, each stage of the examination was significantly shortened using the real-time MR approach. Real-time imaging allows for accurate assessment of left-ventricular-wall motion with the added benefit of decreased examination time. Therefore, it may serve as a cost-efficient alternative in patients with insufficient echocardiography. (orig.)

  3. 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.

  4. 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

    OpenAIRE

    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 moveme...

  5. Controlled motion of domain walls in submicron amorphous wires

    Energy Technology Data Exchange (ETDEWEB)

    Ţibu, Mihai; Lostun, Mihaela; Rotărescu, Cristian; Atiţoaie, Alexandru; Lupu, Nicoleta; Óvári, Tibor-Adrian, E-mail: taovari@phys-iasi.ro; Chiriac, Horia [Department of Magnetic Materials and Devices, National Institute of Research and Development for Technical Physics, Iaşi, 700050 (Romania); Allwood, Dan A. [Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD (United Kingdom)

    2016-05-15

    Results on the control of the domain wall displacement in cylindrical Fe{sub 77.5}Si{sub 7.5}B{sub 15} 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.

  6. Magnet fall inside a conductive pipe: motion and the role of the pipe wall thickness

    Energy Technology Data Exchange (ETDEWEB)

    Donoso, G; Ladera, C L; Martin, P [Departamento de Fisica, Universidad Simon BolIvar, Apdo. 89000, Caracas 1080 (Venezuela, Bolivarian Republic of)], E-mail: clladera@usb.ve, E-mail: pmartin@usb.ve

    2009-07-15

    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 pipes of different materials. Conductive pipes of thinner walls produce less dragging force and the retarded fall of the magnet is seen to consist of an initial transient accelerated regime followed by a stage of uniform motion. Alternative models of the magnet field are also presented that improve the agreement between theory and experiments.

  7. Segmentation of arterial vessel wall motion to sub-pixel resolution using M-mode ultrasound.

    Science.gov (United States)

    Fancourt, Craig; Azer, Karim; Ramcharan, Sharmilee L; Bunzel, Michelle; Cambell, Barry R; Sachs, Jeffrey R; Walker, Matthew

    2008-01-01

    We describe a method for segmenting arterial vessel wall motion to sub-pixel resolution, using the returns from M-mode ultrasound. The technique involves measuring the spatial offset between all pairs of scans from their cross-correlation, converting the spatial offsets to relative wall motion through a global optimization, and finally translating from relative to absolute wall motion by interpolation over the M-mode image. The resulting detailed wall distension waveform has the potential to enhance existing vascular biomarkers, such as strain and compliance, as well as enable new ones.

  8. Motion of a Janus particle very near a wall

    Science.gov (United States)

    Rashidi, Aidin; Wirth, Christopher L.

    2017-12-01

    This article describes the simulated Brownian motion of a sphere comprising hemispheres of unequal zeta potential (i.e., "Janus" particle) very near a wall. The simulation tool was developed and used to assist in the methodology development for applying Total Internal Reflection Microscopy (TIRM) to anisotropic particles. Simulations of the trajectory of a Janus sphere with cap density matching that of the base particle very near a boundary were used to construct 3D potential energy landscapes that were subsequently used to infer particle and solution properties, as would be done in a TIRM measurement. Results showed that the potential energy landscape of a Janus sphere has a transition region at the location of the boundary between the two Janus halves, which depended on the relative zeta potential magnitude. The potential energy landscape was fit to accurately obtain the zeta potential of each hemisphere, particle size, minimum potential energy position and electrolyte concentration, or Debye length. We also determined the appropriate orientation bin size and regimes over which the potential energy landscape should be fit to obtain system properties. Our simulations showed that an experiment may require more than 106 observations to obtain a suitable potential energy landscape as a consequence of the multivariable nature of observations for an anisotropic particle. These results illustrate important considerations for conducting TIRM for anisotropic particles.

  9. Micromagnetic analysis of current-induced domain wall motion in a bilayer nanowire with synthetic antiferromagnetic coupling

    Energy Technology Data Exchange (ETDEWEB)

    Komine, Takashi, E-mail: komine@mx.ibaraki.ac.jp; Aono, Tomosuke [Faculty of Engineering, Ibaraki University 4-12-1, Nakanarusawa, Hitachi, Ibaraki, 316-8511 (Japan)

    2016-05-15

    We demonstrate current-induced domain wall motion in bilayer nanowire with synthetic antiferromagnetic (SAF) coupling by modeling two body problems for motion equations of domain wall. The influence of interlayer exchange coupling and magnetostatic interactions on current-induced domain wall motion in SAF nanowires was also investigated. By assuming the rigid wall model for translational motion, the interlayer exchange coupling and the magnetostatic interaction between walls and domains in SAF nanowires enhances domain wall speed without any spin-orbit-torque. The enhancement of domain wall speed was discussed by energy distribution as a function of wall angle configuration in bilayer nanowires.

  10. ECG-gated blood pool tomography in the determination of left ventricular volume, ejection fraction, and wall motion

    International Nuclear Information System (INIS)

    Underwood, S.R.; Ell, P.J.; Jarritt, P.H.; Emanuel, R.W.; Swanton, R.H.

    1984-01-01

    ECG-gated blood pool tomography promises to provide a ''gold standard'' for noninvasive measurement of left ventricular volume, ejection fraction, and wall motion. This study compares these measurements with those from planar radionuclide imaging and contrast ventriculography. End diastolic and end systolic blood pool images were acquired tomographically using an IGE400A rotating gamma camera and Star computer, and slices were reconstructed orthogonal to the long axis of the heart. Left ventricular volume was determined by summing the areas of the slices, and wall motion was determined by comparison of end diastolic and end systolic contours. In phantom experiments this provided an accurate measurement of volume (r=0.98). In 32 subjects who were either normal or who had coronary artery disease left ventricular volume (r=0.83) and ejection fraction (r=0.89) correlated well with those using a counts based planar technique. In 16 of 18 subjects who underwent right anterior oblique X-ray contrast ventriculography, tomographic wall motion agreed for anterior, apical, and inferior walls, but abnormal septal motion which was not apparent by contrast ventriculography, was seen in 12 subjects tomographically. All 12 had disease of the left anterior descending coronary artery and might have been expected to have abnormal septal motion. ECG-gated blood pool tomography can thus determine left ventricular volume and ejection fraction accurately, and provides a global description of wall motion in a way that is not possible from any single planar image

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

    International Nuclear Information System (INIS)

    Komine, Takashi; Takahashi, Kota; Murakami, Hiroshi; Sugita, Ryuji

    2010-01-01

    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.

  12. 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.

  13. Reproducibility of an automatic quantitation of regional myocardial wall motion and systolic thickening on gated Tc-99m-MIBI myocardial SPECT

    International Nuclear Information System (INIS)

    Paeng, Jin Chul; Lee, Dong Soo; Cheon, Gi Jeong; Kim, Yu Kyeong; Chung, June Key; Lee, Myung Chul

    2000-01-01

    The aim of this study is to investigate the reproducibility of the quantitative assessment of segmental wall motion and systolic thickening provided by an automatic quantitation algorithm. Tc-99m-MIBI gated myocardial SPECT with dipyridamole stress was performed in 31 patients with known or suspected coronary artery disease (4 with single, 6 with two, 11 with triple vessel disease; ejection fraction 51±14%) twice consecutively in the same position. Myocardium was divided into 20 segments. Segmental wall motion and systolic thickening were calculated and expressed in mm and % increase respectively, using AutoQUANT TM software. The reproducibility of this quantitative measurement of wall motion and thickening was tested. Correlations between repeated measurements on consecutive gated SPECT were excellent for wall motion (r=0.95) and systolic thickening (r=0.88). On Bland-Altman analysis, two standard deviation was 2 mm for repeated measurement of segmental wall motion, and 20% for that of systolic thickening. The weighted kappa values of repeated measurements were 0.807 for wall motion and 0.708 for systolic thickening. Sex, perfusion, or segmental location had no influence on reproducibility. Segmental wall motion and systolic thickening quantified using AutoQUANT TM software on gated myocardial SPECT offers good reproducibility and is significantly different when the change is more than 2 mm for wall motion and more than 20% for systolic thickening

  14. Radial motion of the carotid artery wall: A block matching algorithm approach

    Directory of Open Access Journals (Sweden)

    Effat Soleimani

    2012-06-01

    Full Text Available Introduction: During recent years, evaluating the relation between mechanical properties of the arterialwall and cardiovascular diseases has been of great importance. On the other hand, motion estimation of thearterial wall using a sequence of noninvasive ultrasonic images and convenient processing methods mightprovide useful information related to biomechanical indexes and elastic properties of the arteries and assistdoctors to discriminate between healthy and diseased arteries. In the present study, a block matching basedalgorithm was introduced to extract radial motion of the carotid artery wall during cardiac cycles.Materials and Methods: The program was implemented to the consecutive ultrasonic images of thecommon carotid artery of 10 healthy men and maximum and mean radial movement of the posterior wall ofthe artery was extracted. Manual measurements were carried out to validate the automatic method andresults of two methods were compared.Results: Paired t-test analysis showed no significant differences between the automatic and manualmethods (P>0.05. There was significant correlation between the changes in the instantaneous radialmovement of the common carotid artery measured with the manual and automatic methods (withcorrelation coefficient 0.935 and P<0.05.Conclusion: Results of the present study showed that by using a semi automated computer analysismethod, with minimizing the user interfere and no attention to the user experience or skill, arterial wallmotion in the radial direction can be extracted from consecutive ultrasonic frames

  15. Current-induced domain wall motion in magnetic nanowires with spatial variation

    International Nuclear Information System (INIS)

    Ieda, Jun'ichi; Sugishita, Hiroki; Maekawa, Sadamichi

    2010-01-01

    We model current-induced domain wall motion in magnetic nanowires with the variable width. Employing the collective coordinate method we trace the wall dynamics. The effect of the width modulation is implemented by spatial dependence of an effective magnetic field. The wall destination in the potential energy landscape due to the magnetic anisotropy and the spatial nonuniformity is obtained as a function of the current density. For a nanowire of a periodically modulated width, we identify three (pinned, nonlinear, and linear) current density regimes for current-induced wall motion. The threshold current densities depend on the pulse duration as well as the magnitude of wire modulation. In the nonlinear regime, application of ns order current pulses results in wall displacement which opposes or exceeds the prediction of the spin transfer mechanism. The finding explains stochastic nature of the domain wall displacement observed in recent experiments.

  16. Limited diagnostic accuracy of gated myocardial perfusion SPECT for wall motion analysis in patients with asymmetric septal hypertrophy

    International Nuclear Information System (INIS)

    Seo, J.H.; Ahn, B.C.; Bae, J.H.; Jeong, S.Y.; Lee, J.; Lee, K.B.

    2004-01-01

    Objective: Although gated SPECT(G-SPECT) using Tc-99m MIBI is well-known diagnostic modality in the evaluation of myocardial perfusion and wall motion analysis, there were limited reports for subjects with asymmetric septal hypertrophy (ASH). This study was performed to evaluate the clinical usefulness of G-SPECT for assessments of myocardial perfusion and wall motion analysis in patients with ASH on 2D-echocardiography(Echo). Methods: Thirty patients (male 18, 59 12 years) with ASH on Echo (septal wall thickness 13 mm and 1.3 times as thick as that of posterior wall) underwent Tc-99m MIBI G-SPECT. Two studies were performed within one month. No patient had experienced any significant cardiac event, nor had changed medical and surgical therapy during the studies. Functional parameters of the left ventricle were acquired with QGS software(AutoQUANTTM). Three experts performed visual interpretation for the presence of septal thickening and perfusion abnormalities on G-SPECT and two experienced cardiologists measured dimension, thickness and wall motion of the left ventricle on Echo. Results: Mean septum thickness measured by Echo was 1.90 0.50 cm, and the septum/posterior wall thickness ratio was 1.85 0.51. On visual SPECT analysis, 14 patients (46.7%) were interpreted as with thickened septum and 17 patients (57%) as with abnormal perfusion. All 3 patients who underwent coronary angiography showed significant luminal stenosis and also had perfusion abnormalities on SPECT. On Echo, only one patient showed septal hypokinesia, who showed anteroseptal infarction on SPECT, and the others showed normal septal wall motion. But 13 patients (54%) among 24 patients showed septal hypokinesia on G-SPECT. Patients with thickened septum on SPECT had thicker septum (2.3 vs 1.6 cm) and higher septum/posterior wall thickness ratio (2.2 vs 1.6) on Echo, compared with patients without septal thickening on SPECT. Conclusions: Although G-SPECT could proffer diagnostic accuracy for

  17. Evaluation of right ventricular regional wall motion in inferior myocardial infarction by cine MRI

    International Nuclear Information System (INIS)

    Nishino, Masami; Ohnishi, Shusaku; Hasegawa, Shinji

    1991-01-01

    The purpose of this study is to evaluate right ventricular regional wall motion in inferior myocardial infarction by cine MRI. Thirteen patients with inferior myocardial infarction were investigated by cine MRI and were divided into proximal group which consisted of seven patients: >90% stenosis in segment 1 or 2 of right coronary artery and distal group which consisted of six patients: >90% stenosis in segment 3 or 4 of right coronary artery. Cine MRI was performed by 1.5 tesla magnet system (Signa, GE). To depict the regional asynergy, right ventricular wall was divided into 6 segments as follows: Segments 1 and 2 were upper and lower segments in transverse planes, respectively. Segments 3 and 4 were free wall and diaphragmatic segments of outflow tract, and segments 5 and 6 were of inflow tract in sagittal planes. Our results were as follows: (1) In proximal group, right ventricular asynergy was detected in six patients but in distal group it was detected in only one patient; (2) Right ventricular asynergy was detected most frequently at diaphragmatic segments in sagittal planes; (3) All the patients who had shown the hemodynamic deterioration of right ventricle on acute phase of inferior myocardial infarction presented the broad asynergy in right ventricle; (4) Cine MRI is clinically useful in evaluating right ventricular regional wall movement and diagnosing right ventricular infarction. (author)

  18. 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.

  19. Wall Street: money never sleeps : Motion picture (2010)

    OpenAIRE

    Lauri Lucente, Gloria; Buhagiar, Celaine

    2011-01-01

    The Social Network : Harvard student Mark Zuckerberg creates the social networking site that would become known as Facebook, but is later sued by two brothers who claimed he stole their idea, and the cofounder who was later squeezed out of the business. Wall Street: money never sleeps : Now out of prison but still disgraced by his peers, Gordon Gekko works his future son-in-law, an idealistic stock broker, when he sees an opportunity to take down a Wall Street enemy and rebuild his empire.

  20. Strain-encoded cardiac MRI as an adjunct for dobutamine stress testing: incremental value to conventional wall motion analysis.

    Science.gov (United States)

    Korosoglou, Grigorios; Lossnitzer, Dirk; Schellberg, Dieter; Lewien, Antje; Wochele, Angela; Schaeufele, Tim; Neizel, Mirja; Steen, Henning; Giannitsis, Evangelos; Katus, Hugo A; Osman, Nael F

    2009-03-01

    High-dose dobutamine stress MRI is safe and feasible for the diagnosis of coronary artery disease (CAD) in humans. However, the assessment of cine scans relies on the visual interpretation of regional wall motion, which is subjective. Recently, strain-encoded MRI (SENC) has been proposed for the direct color-coded visualization of myocardial strain. The purpose of our study was to compare the diagnostic value of SENC with that provided by conventional wall motion analysis for the detection of inducible ischemia during dobutamine stress MRI. Stress-induced ischemia was assessed by wall motion analysis and by SENC in 101 patients with suspected or known CAD and in 17 healthy volunteers who underwent dobutamine stress MRI in a clinical 1.5-T scanner. Quantitative coronary angiography deemed as the standard reference for the presence or absence of significant CAD (> or =50% diameter stenosis). On a coronary vessel level, SENC detected inducible ischemia in 86 of 101 versus 71 of 101 diseased coronary vessels (P or =50% stenosis (area under the curve, 0.96; SE, 0.01; 95% CI, 0.94 to 0.98; P<0.001). The direct color-coded visualization of strain on MR images is a useful adjunct for dobutamine stress MRI, which provides incremental value for the detection of CAD compared with conventional wall motion readings on cine images.

  1. Interventional heart wall motion analysis with cardiac C-arm CT systems

    International Nuclear Information System (INIS)

    Müller, Kerstin; Maier, Andreas K; Schwemmer, Chris; Hornegger, Joachim; Zheng, Yefeng; Wang, Yang; Lauritsch, Günter; Rohkohl, Christopher; Fahrig, Rebecca

    2014-01-01

    Today, quantitative analysis of three-dimensional (3D) dynamics of the left ventricle (LV) cannot be performed directly in the catheter lab using a current angiographic C-arm system, which is the workhorse imaging modality for cardiac interventions. Therefore, myocardial wall analysis is completely based on the 2D angiographic images or pre-interventional 3D/4D imaging. In this paper, we present a complete framework to study the ventricular wall motion in 4D (3D+t) directly in the catheter lab. From the acquired 2D projection images, a dynamic 3D surface model of the LV is generated, which is then used to detect ventricular dyssynchrony. Different quantitative features to evaluate LV dynamics known from other modalities (ultrasound, magnetic resonance imaging) are transferred to the C-arm CT data. We use the ejection fraction, the systolic dyssynchrony index a 3D fractional shortening and the phase to maximal contraction (ϕ i, max ) to determine an indicator of LV dyssynchrony and to discriminate regionally pathological from normal myocardium. The proposed analysis tool was evaluated on simulated phantom LV data with and without pathological wall dysfunctions. The LV data used is publicly available online at https://conrad.stanford.edu/data/heart. In addition, the presented framework was tested on eight clinical patient data sets. The first clinical results demonstrate promising performance of the proposed analysis tool and encourage the application of the presented framework to a larger study in clinical practice. (paper)

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

    KAUST Repository

    Akosa, Collins Ashu; Kim, Won-Seok; Bisig, André ; Klä ui, Mathias; Lee, Kyung-Jin; Manchon, Aurelien

    2015-01-01

    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.

  3. 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.

  4. 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.

  5. Assessment of left ventricular wall motion and function by cross-sectional echocardiography

    International Nuclear Information System (INIS)

    Ono, Akifumi; Hirata, Shunkichi; Ishikawa, Kyozo

    1982-01-01

    The clinical efficacy of cross-sectional echocardiography (CSE) was evaluated with M-mode echocardiography and radionuclide cardioangiography (RCG) in 50 cases including 30 patients with myocardial infarction. Segmental wall motion by CSE was highly correlated with segmental wall motion and left ventricular ejection fraction by RCG (r = 0.89 in the former, r = -0.84 in the latter). On the other hand, the left ventricular ejection fraction by M-mode echocardiography revealed a fairly well correlation with that by RCG ( r = 0.68). These results suggest that, as compared with RCG, CSE is quite useful in an evaluation of left ventricular function and in a detection of segmental wall motion abnormalities. (author)

  6. Internal friction due to domain-wall motion in martensitically transformed A15 compounds

    International Nuclear Information System (INIS)

    Snead, C.L. Jr.; Welch, D.O.

    1985-01-01

    A lattice instability in A15 materials in some cases leads to a cubic-to-tetragonal martensitic transformation at low temperatures. The transformed material orients in lamellae with c axes alternately aligned along the directions producing domain walls between the lamellae. An internal-friction (delta) feature below T/sub m/ is attributed to stress-induced domain-wall motion. The magnitude of the friction increases as temperature is lowered below T/sub m/ as (1-c/a) increases, and behaves as (1-c/a) 2 from T/sub m/ down to the superconducting critical temperature where the increasing tetragonality is inhibited. The effect of strain in the lattice is to decrease the domain-wall internal friction, but not affect T/sub m/. Neutron-induced disorder and the addition of some third-elements in alloying decrease both delta and T/sub m/, with some elements reducing only the former. Less than 1 at. % H is seen to completely suppress both delta and T/sub m. Martensitically transformed V 2 Zr demonstrates low-temperature internal-friction and modulus behavior consists with easy β/m wall motion relative to the easy m/m motion of the A15's. For the V 2 Zr, a peak in delta is observed, qualitatively in agreement with expected β/m wall motion

  7. Domain wall motion and magnetization reversal processes in a FeSi picture frame single crystal studied by the time-dependent neutron depolarization technique

    International Nuclear Information System (INIS)

    Schaik, F.J. van.

    1979-01-01

    The three dimensional neutron depolarization technique, which gives detailed information about the static properties of ferromagnetic materials, has been extended to a method by means of which the time dependence of magnetic phenomena can be studied. The measurement of the neutron depolarization against time is made possible by applying a periodical magnetic field on the investigated specimen and by continuous sampling of the transmitted neutron intensity in time channels, which are started synchronously with the applied field. The technique has been used in the study of the magnetic domain structure at room temperature of a (010) [001] picture frame FeSi single crystal (3.5 wt.% Si) with outer dimensions of (15 x 10 x 0.26) mm and a frame width of 2.78 mm. (Auth.)

  8. 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...

  9. Magnetic domain-wall motion study under an electric field in a Finemet{sup ®} thin film on flexible substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Ngo Thi [Laboratoire des Sciences des Procédés et des Matériaux, CNRS-Université Paris XIII, 93430 Villetaneuse (France); Mercone, Silvana, E-mail: silvana.mercone@univ-paris13.fr [Laboratoire des Sciences des Procédés et des Matériaux, CNRS-Université Paris XIII, 93430 Villetaneuse (France); Moulin, Johan [Institut d' Electronique Fondamentale, UMR 8622 Université Paris Sud/CNRS, Orsay (France); Bahoui, Anouar El; Faurie, Damien; Zighem, Fatih; Belmeguenai, Mohamed; Haddadi, Halim [Laboratoire des Sciences des Procédés et des Matériaux, CNRS-Université Paris XIII, 93430 Villetaneuse (France)

    2015-01-01

    We study the influence of applied in-plane elastic strains on the static magnetic configuration of a 530 nm magnetostrictive FeCuNbSiB (Finemet{sup ®}) thin film. The in-plane strains are induced via the application of a voltage to a piezoelectric actuator on which the film/substrate system was glued. A quantitative characterization of the voltage dependence of the induced-strain at the surface of the film was performed using a digital image correlation technique. Magnetic Force Microscopy (MFM) images at remanence (H=0 Oe and U=0 V) clearly reveal the presence of weak stripe domains. The effect of the voltage-induced strain shows the existence of a voltage threshold value for the strike configuration break. For a maximum strain of ε{sub XX}∼0.5×10{sup −3} we succeed in destabilizing the stripes configuration helping the setting up of a complete homogeneous magnetic pattern. - Highlights: • Elastic strain effect on the magnetic domain structure of a Finemet/Kapton is investigated. • External loading is applied thanks to a piezo-actuator on which the sample is glued. • The amount of strains was measured by the Digital Image Correlation technique. • Magnetic Force Microscopy showed high mobility of magnetic stripes domains. • Bending, curving and branching of domains go into maze-like pattern.

  10. Fluids in micropores. V. Effects of thermal motion in the walls of a slit-micropore

    International Nuclear Information System (INIS)

    Diestler, D.J.; Schoen, M.

    1996-01-01

    Previous articles in this series have concerned the prototypal slit-pore with rigid walls, in which a Lennard-Jones (12,6) monatomic film is constrained between two plane-parallel walls comprising like atoms fixed in the face-centered-cubic (fcc) (100) configuration. The behavior of molecularly thin films in the rigid-wall prototype is governed by the template effect, whereby solid films can form epitaxially when the walls are properly aligned in the lateral directions. In this article the influence of thermal motion of the wall atoms on the template effect is investigated. The walls are treated as Einstein solids, the atoms moving independently in harmonic potentials centered on rigidly fixed equilibrium positions in the fcc (100) configuration. The force constant f c is a measure of the stiffness of the walls, the rigid-wall limit being f c =∞. Formal thermodynamic and statistical mechanical analyses of the system are carried out. The results of grand canonical ensemble Monte Carlo simulations indicate that for values of f c characteristic of a soft (e.g., noble-gas) crystal dynamic coupling between wall and film has a substantial influence on such equilibrium properties as normal stress (load) and interfacial tensions. In general, the softer the walls (i.e., the smaller the value of f c ), the weaker the template effect and hence the softer and more disordered the confined film. copyright 1996 American Institute of Physics

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

    KAUST Repository

    Ivanov, Yurii P.; Chuvilin, Andrey; Lopatin, Sergei; Kosel, Jü rgen

    2016-01-01

    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.

  12. 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.

  13. 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...

  14. Energy-imbalance mechanism of domain wall motion induced by propagation spin waves in finite magnetic nanostripe

    International Nuclear Information System (INIS)

    Zhu, Jinrong; Han, Zhaoyan; Su, Yuanchang; Hu, Jingguo

    2014-01-01

    The mechanism of the domain wall (DW) motions induced by spin wave in finite magnetic nanostripe is studied by micromagnetic simulations. We find that the spin-wave induced DM motions are always accompanied by an energy imbalance between two sides of the DW. The DW motion can be attributed to the expansion of the low-energy-density area and the contraction of the high-energy-density area. The energy imbalance strongly depends on whether the spin wave passes through the DW or is reflected by the DW. In the area of the spin wave propagation, the energy density increases with the time. However, in the superposition area of the incident spin wave and the reflected spin wave, the energy density decreases with the increasing of the time. It shows that this energy imbalance can be controlled by tuning the frequency of the spin wave. Finally, the effect of the damping parameter value is discussed. - Highlights: • The mechanism of the spin-wave induced DW motions is studied. • The spin-wave induced DW motions and the energy imbalance mechanism are given. • The DW motion with the same direction to that of SW is explained. • The DW motion with the opposite direction to that of SW is explained

  15. 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.

  16. Assessment of ventricular wall motion with focused echocardiography during cardiac arrest to predict survival

    Directory of Open Access Journals (Sweden)

    Can Ozen

    2016-03-01

    Full Text Available Objectives: Our primary goal is to investigate the hypothesis that in patients with a detectable ventricular wall motion (VWM in cardiac ultrasonography (US during cardiopulmonary resuscitation (CPR, survival rate is significantly more than in patients without VWM in US. Material and methods: In our prospective, single center study, 129 adult cardiac arrest (CA patients were enrolled. Cardiac US according to Focus Assessed Transthoracic Echo (FATE protocol was performed before CPR. Presence of VWM was recorded on forms along with demographic data, initial rhythm, CA location, presence of return of spontaneous circulation (ROSC and time until ROSC was obtained. Results: 129 patients were included. ROSC was obtained in 56/77 (72.7% patients with VWM and 3/52 (5.8% patients without VWM which is statistically significant (p > 0.001. Presence of VWM is 95% (95% CI: 0.95–0.99 sensitive and 70% (95% CI: 0.58–0.80 specific for ROSC. 43/77 (55.8% patients with VWM and 1 (1.9% of 52 patients without VWM survived to hospital admission which was statistically significant (p < 0.001. Presence of VWM was 100% (95% CI: 0.87–1.00 sensitive and 54% (95% CI: 0.43–0.64 specific for survival to hospital admission. Conclusion: No patient without VWM in US survived to hospital discharge. Only 3 had ROSC in emergency department and only 1 survived to hospital admission. This data suggests no patient without VWM before the onset of CPR survived to hospital discharge and this may be an indication to end resuscitative efforts early in these patients. Keywords: Cardiopulmonary resuscitation, Ultrasonography, Echocardiography, Ventricular wall motion

  17. Damping of the domain walls motion in Co-based amorphous ribbons with helical magnetic anisotropy: Part III

    International Nuclear Information System (INIS)

    Zhmetko, D.N.; Zhmetko, S.D.

    2009-01-01

    The damping of the motion of domain walls of a sandwich domain structure by the eddy currents magnetic fields, the stray fields and the hysteresis friction fields is investigated. The blocking of the motion of domain walls by the eddy currents magnetic fields is discovered.

  18. 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.

  19. Myocardial metabolism, perfusion, wall motion and electrical activity in Duchenne muscular dystrophy

    International Nuclear Information System (INIS)

    Perloff, J.K.; Henze, E.; Schelbert, H.R.

    1982-01-01

    The cardiomyopathy of Duchenne's muscular dystrophy originates in the posterobasal left ventricle and extends chiefly to the contiguous lateral wall. Ultrastructural abnormalities in these regions precede connective tissue replacement. We postulated that a metabolic fault coincided with or antedated the subcellular abnormality. Accordingly, regional left ventricular metabolism, perfusion and wall motion were studied using positron computed tomography and metabolic isotopes supplemented by thallium perfusion scans, equilibrium radionuclide angiography and M-mode and two-dimensional echocardiography. To complete the assessment, electrocardiograms, vectorcardiograms, 24 hour taped electrocardiograms and chest x-rays were analyzed. Positron computed tomography utilizing F-18 2-fluoro 2-deoxyglucose (FDG) provided the first conclusive evidence supporting the hypothesis of a premorphologic regional metabolic fault. Thus, cardiac involvement in duchenne dystrophy emerges as a unique form of heart disease, genetically targeting specific regions of ventricular myocardium for initial metabolic and subcellular changes. Reported ultrastructural abnormalities of the impulse and conduction systems provide, at least in part, a basis for the clinically observed sinus node, intraatrial, internodal, AV nodal and infranodal disorders

  20. 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′).

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

    KAUST Repository

    Elí as, Ricardo Gabriel; Vidal-Silva, Nicolas; Manchon, Aurelien

    2017-01-01

    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′).

  2. Changes in dynamic embryonic heart wall motion in response to outflow tract banding measured using video densitometry

    Science.gov (United States)

    Stovall, Stephanie; Midgett, Madeline; Thornburg, Kent; Rugonyi, Sandra

    2016-11-01

    Abnormal blood flow during early cardiovascular development has been identified as a key factor in the pathogenesis of congenital heart disease; however, the mechanisms by which altered hemodynamics induce cardiac malformations are poorly understood. This study used outflow tract (OFT) banding to model increased afterload, pressure, and blood flow velocities at tubular stages of heart development and characterized the immediate changes in cardiac wall motion due to banding in chicken embryo models with light microscopy-based video densitometry. Optical videos were used to acquire two-dimensional heart image sequences over the cardiac cycle, from which intensity data were extracted along the heart centerline at several locations in the heart ventricle and OFT. While no changes were observed in the synchronous contraction of the ventricle with banding, the peristaltic-like wall motion in the OFT was significantly affected. Our data provide valuable insight into early cardiac biomechanics and its characterization using a simple light microscopy-based imaging modality.

  3. Segmental wall-motion analysis in the right anterior oblique projection: comparison of exercise equilibrium radionuclide ventriculography and exercise contrast ventriculography

    International Nuclear Information System (INIS)

    Brady, T.J.; Thrall, J.H.; Keyes, J.W. Jr.; Brymer, J.F.; Walton, J.A.; Pitt, B.

    1980-01-01

    Thirty-nine patients with known or suspected coronary artery disease were studied at rest and during supine bicycle exercise with radionuclide and contrast left ventriculography. Analysis of regional wall motion was made by visual evaluation of the five standard 30 0 right anterior oblique (RAO) wall segments in the contrast images and the corresponding 10 0 RAO radionuclide segments. The radionuclide studies were evaluated independently by three observers using a five-point grading system. The interobserver wall-motion grading agreed completely in more than 80% of segments at rest and exercise, and agreed within one wall-motion grade in more than 95% of segments. The comparison of wall-motion grades between radionuclide and contrast ventriculograms showed complete agreement in 86% of segments at rest and in 78% during exercise, and agreement within one wall-motion grade in 97% of rest and 96% of exercise segments. Visual evaluation of 10 0 RAO rest and exercise radionuclide ventriculograms compares favorably with rest and exercise 30 0 RAO contrast ventriculograms and demonstrates satisfactory interobserver agreement

  4. 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.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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

  6. Left ventricular wall motion abnormalities evaluated by factor analysis as compared with Fourier analysis

    International Nuclear Information System (INIS)

    Hirota, Kazuyoshi; Ikuno, Yoshiyasu; Nishikimi, Toshio

    1986-01-01

    Factor analysis was applied to multigated cardiac pool scintigraphy to evaluate its ability to detect left ventricular wall motion abnormalities in 35 patients with old myocardial infarction (MI), and in 12 control cases with normal left ventriculography. All cases were also evaluated by conventional Fourier analysis. In most cases with normal left ventriculography, the ventricular and atrial factors were extracted by factor analysis. In cases with MI, the third factor was obtained in the left ventricle corresponding to wall motion abnormality. Each case was scored according to the coincidence of findings of ventriculography and those of factor analysis or Fourier analysis. Scores were recorded for three items; the existence, location, and degree of asynergy. In cases of MI, the detection rate of asynergy was 94 % by factor analysis, 83 % by Fourier analysis, and the agreement in respect to location was 71 % and 66 %, respectively. Factor analysis had higher scores than Fourier analysis, but this was not significant. The interobserver error of factor analysis was less than that of Fourier analysis. Factor analysis can display locations and dynamic motion curves of asynergy, and it is regarded as a useful method for detecting and evaluating left ventricular wall motion abnormalities. (author)

  7. 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

  8. 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)

  9. Processive motions of MreB micro-filaments coordinate cell wall growth

    Science.gov (United States)

    Garner, Ethan

    2012-02-01

    Rod-shaped bacteria elongate by the action of cell-wall synthesis complexes linked to underlying dynamic MreB filaments, but how these proteins function to allow continued elongation as a rod remains unknown. To understand how the movement of these filaments relates to cell wall synthesis, we characterized the dynamics of MreB and the cell wall elongation machinery using high-resolution particle tracking in Bacillus subtilis. We found that both MreB and the elongation machinery move in linear paths across the cell, moving at similar rates (˜20nm / second) and angles to the cell body, suggesting they function as single complexes. These proteins move circumferentially around the cell, principally perpendicular to its length. We find that the motions of these complexes are independent, as they can pause and reverse,and also as nearby complexes move independently in both directions across one surface of the cell. Inhibition of cell wall synthesis with antibiotics or depletions in the cell wall synthesis machinery blocked MreB movement, suggesting that the cell wall synthetic machinery is the motor in this system. We propose that bacteria elongate by the uncoordinated, circumferential movements of synthetic complexes that span the plasma membrane and insert radial hoops of new peptidoglycan during their transit.

  10. Temporal Fourier transform of digital angiograms for left ventricular regional wall motion analysis

    International Nuclear Information System (INIS)

    Katayama, Kazuhiro; Guth, B.D.; Widmann, T.F.; Lee, Jong-Dae; Seitelberger, R.; Peterson, K.L.

    1988-01-01

    To determine whether or not the first harmonic of a temporal Fourier transform, applied pixel-by-pixel on time-intensity curves, can detect the subtle wall motion abnormalities due to ischemia, 6 dogs were instrumented with a micromanometer in the left ventricles, a hydraulic cuff occluder around the circumflex coronary artery, and sonomicrometers on the inferior (ischemic) and anterior (non-ischemic) walls. Left ventricular images, obtained after contrast injection via the pulmonary artery, were compared with dimension signals in control and 3 progressive levels of coronary stenosis (Stenosis I, II and III). Normalized, digital functional images (512 x 512 matrix, 256 shades of gray/pixel) were divided into anterior, apical, and inferior areas to acquire regional mean phase (degrees) and amplitude (intensity units) values. After inducing stenosis, phase in ischemic region significantly increased at all 3 levels of stenosis, whereas amplitude significantly decreased at Stenosis II and III. However, amplitude images showed clearly the topographic site of ischemia. There was a progressive increase in phase and decrease in amplitude in ischemic areas as the percent wall thickening (%WTh) fell (phase vs. %WTh: r = -0.55, p < 0.005; amplitude vs. %WTh: r = 0.71, p < 0.001). Heart rate and peak systolic pressure showed no significant changes during stenoses. We conclude that quantitative functional images, generated from a temporal Fourier transform, are sensitive to the detection of left ventricular regional wall motion abnormalities during mild, moderate, and severe degrees of ischemia. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Nasseri, S. Ali, E-mail: ali.nasseri@isi.it [ISI Foundation - Via Alassio 11/c –10126 Torino (Italy); Politecnico di Torino - Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Moretti, Simone; Martinez, Eduardo [University of Salamanca - Cardenal Plá y Deniel, 22, 37008 Salamanca (Spain); Serpico, Claudio [ISI Foundation - Via Alassio 11/c –10126 Torino (Italy); University of Naples Federico II - Via Claudio 21, 80125 Napoli (Italy); Durin, Gianfranco [ISI Foundation - Via Alassio 11/c –10126 Torino (Italy); Istituto Nazionale di Ricerca Metrologica (INRIM) - Strada delle Cacce 91, 10135 Torino (Italy)

    2017-03-15

    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. - Highlights: • Moving DWs in PMA material maintain their structure under longitudinal in-plane fields. • As a result of longitudinal fields, magnetization in the domains becomes canted. • A critical longitudinal field was identified and correlated with the DMI strength. • A canted collective coordinate model was developed for DW motion under in-plane fields.

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

    International Nuclear Information System (INIS)

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

    1984-01-01

    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.)

  13. Ground motion input in seismic evaluation studies

    International Nuclear Information System (INIS)

    Sewell, R.T.; Wu, S.C.

    1996-07-01

    This report documents research pertaining to conservatism and variability in seismic risk estimates. Specifically, it examines whether or not artificial motions produce unrealistic evaluation demands, i.e., demands significantly inconsistent with those expected from real earthquake motions. To study these issues, two types of artificial motions are considered: (a) motions with smooth response spectra, and (b) motions with realistic variations in spectral amplitude across vibration frequency. For both types of artificial motion, time histories are generated to match target spectral shapes. For comparison, empirical motions representative of those that might result from strong earthquakes in the Eastern U.S. are also considered. The study findings suggest that artificial motions resulting from typical simulation approaches (aimed at matching a given target spectrum) are generally adequate and appropriate in representing the peak-response demands that may be induced in linear structures and equipment responding to real earthquake motions. Also, given similar input Fourier energies at high-frequencies, levels of input Fourier energy at low frequencies observed for artificial motions are substantially similar to those levels noted in real earthquake motions. In addition, the study reveals specific problems resulting from the application of Western U.S. type motions for seismic evaluation of Eastern U.S. nuclear power plants

  14. Relation of external surface to internal tumor motion studied with cine CT

    International Nuclear Information System (INIS)

    Chi, P.-C.M.; Balter, Peter; Luo Dershan; Mohan, Radhe; Pan Tinsu

    2006-01-01

    The accuracy of delivering gated-radiation therapy to lung tumors using an external respiratory surrogate relies on not only interfractional and intrafractional reproducibility, but also a strong correlation between external motion and internal tumor motion. The purpose of this work was to use the cine images acquired by four-dimensional computed tomography acquisition protocol to study the relation between external surface motion and internal tumor motion. The respiratory phase information of tumor motion and chest wall motion was measured on the cine images using a proposed region-of-interest (ROI) method and compared to measurement of an external respiratory monitoring device. On eight lung patient data sets, the phase shifts were measured between (1) the signal of a real-time positioning-management (RPM) respiratory monitoring device placed in the abdominal region and four surface locations on the chest wall (2) the RPM signal in the abdominal region and tumor motions, and (3) chest wall surface motions and tumor motions. Respiratory waveforms measured at different surface locations during the same respiratory cycle often varied and had significant phase shifts. Seven of the 8 patients showed the abdominal motion leading chest wall motion. The best correlation (smallest phase shift) was found between the abdominal motion and the superior-inferior (S-I) tumor motion. A wide range of phase shifts was observed between external surface motion and tumor anterior-posterior (A-P)/lateral motion. The result supported the placement of the RPM block in the abdominal region and suggested that during a gated therapy utilizing the RPM system, it is necessary to place the RPM block at the same location as it is during treatment simulation in order to reduce potential errors introduced by the position of the RPM block. Correlations between external motions and lateral/A-P tumor motions were inconclusive due to a combination of patient selection and the limitation of the ROI

  15. Cervical spine motion: radiographic study

    International Nuclear Information System (INIS)

    Morgan, J.P.; Miyabayashi, T.; Choy, S.

    1986-01-01

    Knowledge of the acceptable range of motion of the cervical spine of the dog is used in the radiographic diagnosis of both developmental and degenerative diseases. A series of radiographs of mature Beagle dogs was used to identify motion within sagittal and transverse planes. Positioning of the dog's head and neck was standardized, using a restraining board, and mimicked those thought to be of value in diagnostic radiology. The range of motion was greatest between C2 and C5. Reports of severe disk degeneration in the cervical spine of the Beagle describe the most severely involved disks to be C4 through C7. Thus, a high range of motion between vertebral segments does not seem to be the cause for the severe degenerative disk disease. Dorsoventral slippage between vertebral segments was seen, but was not accurately measured. Wedging of disks was clearly identified. At the atlantoaxio-occipital region, there was a high degree of motion within the sagittal plane at the atlantoaxial and atlanto-occipital joints; the measurement can be a guideline in the radiographic diagnosis of instability due to developmental anomalies in this region. Lateral motion within the transverse plane was detected at the 2 joints; however, motion was minimal, and the measurements seemed to be less accurate because of rotation of the cervical spine. Height of the vertebral canal was consistently noted to be greater at the caudal orifice, giving some warning to the possibility of overdiagnosis in suspected instances of cervical spondylopathy

  16. Comparison of Quantitative Wall Motion Analysis and Strain For Detection Of Coronary Stenosis With Three-Dimensional Dobutamine Stress Echocardiography

    Science.gov (United States)

    Parker, Katherine M.; Clark, Alexander P.; Goodman, Norman C.; Glover, David K.; Holmes, Jeffrey W.

    2015-01-01

    Background Quantitative analysis of wall motion from three-dimensional (3D) dobutamine stress echocardiography (DSE) could provide additional diagnostic information not available from qualitative analysis. In this study we compare the effectiveness of 3D fractional shortening (3DFS), a measure of wall motion computed from 3D echocardiography (3DE), to strain and strain rate measured with sonomicrometry for detecting critical stenoses during DSE. Methods Eleven open-chest dogs underwent DSE both with and without a critical stenosis. 3DFS was measured from 3DE images acquired at peak stress. 3DFS was normalized by subtracting average 3DFS during control peak stress (Δ3DFS). Strains in the perfusion defect (PD) were measured from sonomicrometry, and PD size and location were measured with microspheres. Results A Δ3DFS abnormality indicated the presence of a critical stenosis with high sensitivity and specificity (88% and 100%, respectively), and Δ3DFS abnormality size correlated with PD size (R2=0.54). The sensitivity and specificity for Δ3DFS was similar to that for area strain (88%, 100%) and circumferential strain and strain rate (88%, 92% and 88%, 86%, respectively), while longitudinal strain and strain rate were less specific. Δ3DFS correlated significantly with both coronary flow reserve (R2=0.71) and PD size (R2=0.97), while area strain correlated with PD size only (R2=0.67), and other measures were not significantly correlated with flow reserve or PD size. Conclusion Quantitative wall motion analysis using Δ3DFS is effective for detecting critical stenoses during DSE, performing similarly to 3D strain, and provides potentially useful information on the size and location of a perfusion defect. PMID:24815588

  17. Both semiquantitative degree of rest Tl-201 uptake and reversibility at 24 hour-delay were needed to predict wall motion improvement after bypass surgery

    International Nuclear Information System (INIS)

    Lee, D. S.; Yoon, S. N.; Kim, K. B.; Jeong, Z. K.; Lee, M. C.; Ko, C. S.

    1997-01-01

    Controversy still exists about how to use the uptake at rest and 24 hour delay in rest redistribution Tl-201 SPECT to predict improvement of wall motion abnormality after bypass surgery. To find the best way to combine diagnostic efficacy of Tl-201 SPECT to predict myocardial viability, we studied the predictive values (positive: PPV, negative: NPV) of rest and 24 hour-delay Tl-201 SPECT in 21 patients. Wall motion was assessed comparing preoperative post-stress gated Tc-99m-MIBI SPECT with that of 3 months after surgery. Four point scoring system was used for 17 myocardial segments to asses uptakes ( 0 to 3 for normal to defect) at rest and 24 hour-delay and wall motion ( 0 to 3 for normal to dyskinesia). Ejection fraction improved after surgery (5011% vs 4313%). Intra-observer and inter-observer reproducibility of EF was 7 and 9% respectively when we used 3D Perfusion-Motion Map. Sixty seven segments showed wall motion abnormality before surgery. Predictive values of rest Tl-201 uptake decrease were as follows: 0: 15/15(100%), 1: 30/34(88%), 2: 6/11 (55%), 3: 3/7(43%). So PPV of mild decrease was 88%, and NPV of severe decrease was 50%. Delayed reversibility was evaluated in 37 segments (15 patients). Twenty seven segment had persistence or aggravation, but the other 10 segments improved at 24 hour delay. PPV of reversible 10 segments was 80%, and NPV of reversibility was only 46%. PPV of combination of rest Tl-201 uptake of mild degree and 24 hour reversibility was 86% (38/44) and NPV of neither one was 88%. We concluded that both semi-quantitative degree of Tl-201 uptake at rest and reversibility at 24 hour delay was the best to warrant or abandon postoperative improvement of abnormal wall motion found at preoperative post-stress gated myocardial SPECT

  18. Motion control in double-walled carbon nanotube systems using a Stone-Thrower-Wales defect cluster

    International Nuclear Information System (INIS)

    Liu Ping; Zhang Yongwei

    2010-01-01

    The ability to control the motion of a single molecule will have an important impact in nano-mechanical systems. Multi-walled carbon nanotube systems, which have extremely low intertube friction and strong motion confinement, can form the basis for mechanically based motion control. We devise two molecular motion control units based on double-walled carbon nanotubes embedded with a Stone-Thrower-Wales defect cluster, and perform molecular dynamics simulations to determine the characteristics of these two control units. We show that one of the molecular control units is able to perform a logic operation on one logic input and produce three logic outputs, while the other is able to produce two logic outputs. Potential applications of the motion control units include molecular switches, shuttles and mechanically based logic devices.

  19. 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.

  20. 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

    2010-03-01

    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 (Pvolume during the isovolume maneuver (standard deviationpulmonary functional differences between the diseased and the contralateral sides of the thorax, and subsequent improvement of this imbalance after drainage. These results demonstrate the proposed optical method is capable of not only whole respiratory volume evaluation with high accuracy, but also regional pulmonary function assessment in different chest wall behaviors, with the advantage of whole-field measurement.

  1. Peculiarities of low-frequency dielectric spectra and domain wall motion in gadolinium molybdate

    International Nuclear Information System (INIS)

    Galiyarova, N.M.; Gorin, S.V.; Dontsova, L.I.; Shil'nikov, A.V.; Shuvalov, L.A.

    1994-01-01

    Low-frequency Debye dispersion of dielectric permeability in GMO with the low values of high-frequency limit ε ∞ was investigated in a wide temperature range as well as in fields of variable amplitude. The features of domain boundaries motion were studied at the partial repolarization in monopolar P-pulsed fields. The model of cooperationrelaxation motion brifing in parallel with positive to negative contribution to polarization that explained the low values of ε ∞ was suggested

  2. Serial thallium-201 myocardial imaging after dipyridamole infusion: diagnostic utility in detecting coronary stenoses and relationship to regional wall motion

    International Nuclear Information System (INIS)

    Leppo, J.; Boucher, C.A.; Okada, R.D.; Newell, J.B.; Strauss, H.W.; Pohost, G.M.

    1982-01-01

    After a 4-minute i.v. dipyridamole infusion, 0.14 mg/kg/min, serial thallium-201 scans were obtained in 60 patients undergoing cardia catheterization. Forty patients had significant (greater than or equal to50% stenosis) coronary artery disease (CAD), and 20 patients had normal coronary arteries or trivial lesions. The images were graded qualitatively for thallium activity by three observers. Sensitivity was 93% (37 of 40) and specificity was 80% (16 of 20). The sensitivity and specificity of the thallium-201 study were not affected by the extent of CAD, the presence of Q waves, or propranolol therapy. Twenty-seven of 37 patients who had initial defects (73%) had complete thallium redistribution of one or more defects. Patient-by-patient anlaysis using a regression model of all patients showed that the fate of a segmental thallium defect predicted abnormal wall motion by angiography better than ECG Q waves. The presence of propranolol therapy or collaterals did not significantly affect the thallium redistribution results. It is concluded that qualitative interpretation by multiple observers of thallium images after dipyridamole infusion is a highly sensitive and specific test for CAD. After dipyridamole, as with exercise stress, the extent of thallium redistribution is related to the degree of myocardial wall motion abnormality

  3. A Motion Planning Approach to Studying Molecular Motions

    KAUST Repository

    Amato, Nancy M.

    2010-01-01

    While structurally very different, protein and RNA molecules share an important attribute. The motions they undergo are strongly related to the function they perform. For example, many diseases such as Mad Cow disease or Alzheimer\\'s disease are associated with protein misfolding and aggregation. Similarly, RNA folding velocity may regulate the plasmid copy number, and RNA folding kinetics can regulate gene expression at the translational level. Knowledge of the stability, folding, kinetics and detailed mechanics of the folding process may help provide insight into how proteins and RNAs fold. In this paper, we present an overview of our work with a computational method we have adapted from robotic motion planning to study molecular motions. We have validated against experimental data and have demonstrated that our method can capture biological results such as stochastic folding pathways, population kinetics of various conformations, and relative folding rates. Thus, our method provides both a detailed view (e.g., individual pathways) and a global view (e.g., population kinetics, relative folding rates, and reaction coordinates) of energy landscapes of both proteins and RNAs. We have validated these techniques by showing that we observe the same relative folding rates as shown in experiments for structurally similar protein molecules that exhibit different folding behaviors. Our analysis has also been able to predict the same relative gene expression rate for wild-type MS2 phage RNA and three of its mutants.

  4. Dominance of free wall radial motion in global right ventricular function of heart transplant recipients.

    Science.gov (United States)

    Lakatos, Bálint Károly; Tokodi, Márton; Assabiny, Alexandra; Tősér, Zoltán; Kosztin, Annamária; Doronina, Alexandra; Rácz, Kristóf; Koritsánszky, Kinga Bianka; Berzsenyi, Viktor; Németh, Endre; Sax, Balázs; Kovács, Attila; Merkely, Béla

    2018-03-01

    Assessment of right ventricular (RV) function using conventional echocardiography might be inadequate as the radial motion of the RV free wall is often neglected. Our aim was to quantify the longitudinal and the radial components of RV function using three-dimensional (3D) echocardiography in heart transplant (HTX) recipients. Fifty-one HTX patients in stable cardiovascular condition without history of relevant rejection episode or chronic allograft vasculopathy and 30 healthy volunteers were enrolled. RV end-diastolic (EDV) volume and total ejection fraction (TEF) were measured by 3D echocardiography. Furthermore, we quantified longitudinal (LEF) and radial ejection fraction (REF) by decomposing the motion of the RV using the ReVISION method. RV EDV did not differ between groups (HTX vs control; 96 ± 27 vs 97 ± 2 mL). In HTX patients, TEF was lower, however, tricuspid annular plane systolic excursion (TAPSE) decreased to a greater extent (TEF: 47 ± 7 vs 54 ± 4% [-13%], TAPSE: 11 ± 5 vs 21 ± 4 mm [-48%], P < .0001). In HTX patients, REF/TEF ratio was significantly higher compared to LEF/TEF (REF/TEF vs LEF/TEF: 0.58 ± 0.10 vs 0.27 ± 0.08, P < .0001), while in controls the REF/TEF and LEF/TEF ratio was similar (0.45 ± 0.07 vs 0.47 ± 0.07). Current results confirm the superiority of radial motion in determining RV function in HTX patients. Parameters incorporating the radial motion are recommended to assess RV function in HTX recipients. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. 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.)

  6. Predictive values of early rest/24 hour delay Tl-201 perfusion SPECT for wall motion improvement in patients with acute myocardial infarction after reperfusion

    International Nuclear Information System (INIS)

    Hyun, In Young; Kwan, June

    1998-01-01

    We studied early rest/24 hour delay Tl-201 perfusion SPECT for prediction of wall motion improvement after reperfusion in patients with acute myocardial infarction. Among 17 patients (male/female=11/6, age: 59±13) with acute myocardial infarction, 15 patients were treated with percutaneous transcoronary angioplasty (direct:2, delay:11) and intravenous urokinase (2). Spontaneous resolution occurred in infarct related arteries of 2 patients. We confirmed TIMI 3 flow of infarct-related artery after reperfusion in all patients with coronary angiography. We performed rest Tl-201 perfusion SPECT less then 6 hours after reperfusion and delay Tl-201 perfusion SPECT next day. Tl-201 uptake was visually graded as 4 point score from normal (0) to severe defect (3). Rest Tl-201 uptake ≤2 or combination of rest Tl-201 uptake ≤2 or late reversibility were considered to be viable. Myocardial wall motion was graded as 5 point score from normal (1) to dyskinesia (5). Myocardial wall motion was considered to be improved when a segment showed an improvement ≥1 grade in follow up echo compared with the baseline values. Among 98 segments with wall motion abnormality, the severity of myocardial wall motion decrease was as follow: mild hypokinesia: 18/98 (18%), severe hypokinesia: 28/98 (29%), akinesia: 51/98 (52%), dyskinesia: 1/98 (1%). The wall motion improved in 85%. Redistribution (13%), and reverse redistribution (4%) were observed in 24 hour delay SPECT. Positive predictive value (PPV) and negative predictive value (NPV) of combination of late reversibility and rest Tl-201uptake were 99%, and 54%.PPV and NPV of rest Tl-201 uptake were 100% and 52% respectively. Predictive values of comibination of rest Tl-201 uptake and late reversibility were not significantly different compared with predictive values of rest Tl-201 uptake only. We conclude that early Tl-201 perfusion SPECT predict myocardial wall motion improvement with excellent positive but relatively low negative

  7. 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.

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

    KAUST Repository

    Ivanov, Yurii P.; Chuvilin, Andrey; Lopatin, Sergei; Mohammed, Hanan; Kosel, Jü rgen

    2017-01-01

    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.

  9. The stochastic nature of the domain wall motion along high perpendicular anisotropy strips with surface roughness

    International Nuclear Information System (INIS)

    Martinez, Eduardo

    2012-01-01

    The domain wall dynamics along thin ferromagnetic strips with high perpendicular magnetocrystalline anisotropy driven by either magnetic fields or spin-polarized currents is theoretically analyzed by means of full micromagnetic simulations and a one-dimensional model, including both surface roughness and thermal effects. At finite temperature, the results show a field dependence of the domain wall velocity in good qualitative agreement with available experimental measurements, indicating a low field, low velocity creep regime, and a high field, linear regime separated by a smeared depinning region. Similar behaviors were also observed under applied currents. In the low current creep regime the velocity-current characteristic does not depend significantly on the non-adiabaticity. At high currents, where the domain wall velocity becomes insensitive to surface pinning, the domain wall shows a precessional behavior even when the non-adiabatic parameter is equal to the Gilbert damping. These analyses confirm the relevance of both thermal fluctuations and surface roughness for the domain wall dynamics, and that complete micromagnetic modeling and one-dimensional studies taking into account these effects are required to interpret the experimental measurements in order to get a better understanding of the origin, the role and the magnitude of the non-adiabaticity. (paper)

  10. Roughness Effects on Organized Motions in a Wall Shear Layer Flow

    Science.gov (United States)

    Haigermoser, Christian; Vesely, Lukas; Lapolla, Massimillano; Onorato, Michele

    2006-11-01

    Turbulent boundary layer measurements on a zero-pressure gradient flat plate with two different roughness, a 2D and a 3D roughness, were carried out. The main object of the study was to investigate the impact of the wall roughness on the turbulent flow structures. The momentum thickness Reynolds number for the smooth wall was Reθ˜ 1900. PIV measurements were taken in the streamwise wall-normal plane. The PIV images covered the whole logarithmic region and the major part of the outer layer. The instant flow images for the two roughness show features similar to the one expected in a smooth wall turbulent boundary layer, as described by Adrian et al. (JFM 2000). Statistical analysis was performed to enlighten quantitative differences between the different flow fields. For instance, two point streamwise velocity correlations show that the major effect of the roughness is to tilt the inclination of the hairpin vortex packets towards the wall normal direction; being the 3D roughness more effective in producing this displacement. Full results will be shown and discussed during the presentation.

  11. 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…

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

    KAUST Repository

    Bang, Do; Yu, Jiawei; Qiu, Xuepeng; Wang, Yi; Awano, Hiroyuki; Manchon, Aurelien; Yang, Hyunsoo

    2016-01-01

    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.

  13. 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.

  14. Rotational Response of Toe-Restrained Retaining Walls to Earthquake Ground Motions

    National Research Council Canada - National Science Library

    Ebeling, Robert M; White, Barry C

    2006-01-01

    .... The PC software CorpsWallRotate (sometimes referred to as CWRotate) was developed to perform an analysis of permanent wall rotation for each proposed retaining wall section to a user-specified earthquake acceleration time-history...

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

    International Nuclear Information System (INIS)

    Herrera Diez, L.; García-Sánchez, F.; Adam, J.-P.; Devolder, T.; Eimer, S.; El Hadri, M. S.; Ravelosona, D.; Lamperti, A.; Mantovan, R.; Ocker, B.

    2015-01-01

    This study presents the effective tuning of perpendicular magnetic anisotropy in CoFeB/MgO thin films by He + 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 −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 dep . In turn, H* ≈ H 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

  16. 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.

  17. Carotid artery wall motion analysis from B-mode ultrasound using adaptive block matching: in silico evaluation and in vivo application

    International Nuclear Information System (INIS)

    Gastounioti, A; Stoitsis, J S; Nikita, K S; Golemati, S

    2013-01-01

    Valid risk stratification for carotid atherosclerotic plaques represents a crucial public health issue toward preventing fatal cerebrovascular events. Although motion analysis (MA) provides useful information about arterial wall dynamics, the identification of motion-based risk markers remains a significant challenge. Considering that the ability of a motion estimator (ME) to handle changes in the appearance of motion targets has a major effect on accuracy in MA, we investigated the potential of adaptive block matching (ABM) MEs, which consider changes in image intensities over time. To assure the validity in MA, we optimized and evaluated the ABM MEs in the context of a specially designed in silico framework. ABM FIRF2 , which takes advantage of the periodicity characterizing the arterial wall motion, was the most effective ABM algorithm, yielding a 47% accuracy increase with respect to the conventional block matching. The in vivo application of ABM FIRF2 revealed five potential risk markers: low movement amplitude of the normal part of the wall adjacent to the plaques in the radial (RMA PWL ) and longitudinal (LMA PWL ) directions, high radial motion amplitude of the plaque top surface (RMA PTS ), and high relative movement, expressed in terms of radial strain (RSI PL ) and longitudinal shear strain (LSSI PL ), between plaque top and bottom surfaces. The in vivo results were reproduced by OF LK(WLS) and ABM KF-K2 , MEs previously proposed by the authors and with remarkable in silico performances, thereby reinforcing the clinical values of the markers and the potential of those MEs. Future in vivo studies will elucidate with confidence the full potential of the markers. (paper)

  18. Comparison of Kalman-filter-based approaches for block matching in arterial wall motion analysis from B-mode ultrasound

    International Nuclear Information System (INIS)

    Gastounioti, A; Stoitsis, J; Nikita, K S; Golemati, S

    2011-01-01

    Block matching (BM) has been previously used to estimate motion of the carotid artery from B-mode ultrasound image sequences. In this paper, Kalman filtering (KF) was incorporated in this conventional method in two distinct scenarios: (a) as an adaptive strategy, by renewing the reference block and (b) by renewing the displacements estimated by BM or adaptive BM. All methods resulting from combinations of BM and KF with the two scenarios were evaluated on synthetic image sequences by computing the warping index, defined as the mean squared error between the real and estimated displacements. Adaptive BM, followed by an update through the second scenario at the end of tracking, ABM K F-K2, minimized the warping index and yielded average displacement error reductions of 24% with respect to BM. The same method decreased estimation bias and jitter over varying center frequencies by 30% and 64%, respectively, with respect to BM. These results demonstrated the increased accuracy and robustness of ABM K F-K2 in motion tracking of the arterial wall from B-mode ultrasound images, which is crucial in the study of mechanical properties of normal and diseased arterial segments

  19. A Motion Planning Approach to Studying Molecular Motions

    KAUST Repository

    Amato, Nancy M.; Tapia, Lydia; Thomas, Shawna

    2010-01-01

    While structurally very different, protein and RNA molecules share an important attribute. The motions they undergo are strongly related to the function they perform. For example, many diseases such as Mad Cow disease or Alzheimer's disease

  20. Spin Hall driven domain wall motion in magnetic bilayers coupled by a magnetic oxide interlayer

    Science.gov (United States)

    Liu, Yang; Furuta, Masaki; Zhu, Jian-Gang Jimmy

    2018-05-01

    mCell, previously proposed by our group, is a four-terminal magnetoresistive device with isolated write- and read-paths for all-spin logic and memory applications. A mCell requires an electric-insulating magnetic layer to couple the spin Hall driven write-path to the magnetic free layer of the read-path. Both paths are magnetic layers with perpendicular anisotropy and their perpendicularly oriented magnetization needs to be maintained with this insertion layer. We have developed a magnetic oxide (FeOx) insertion layer to serve for these purposes. We show that the FeOx insertion layer provides sufficient magnetic coupling between adjacent perpendicular magnetic layers. Resistance measurement shows that this magnetic oxide layer can act as an electric-insulating layer. In addition, spin Hall driven domain wall motion in magnetic bi-layers coupled by the FeOx insertion layer is significantly enhanced compared to that in magnetic single layer; it also requires low voltage threshold that poses possibility for power-efficient device applications.

  1. Comparison of various quantization methods of segmental ventricular wall motion in ischemic heart disease

    International Nuclear Information System (INIS)

    Probst, P.; Moore, R.; Kim, S.W.; Zollikofer, C.; Amplatz, K.

    1981-01-01

    Numerous methods of measuring regional myocardial wall motion are in use. A critical comparison is needed to assess the strengths, weaknesses, accuracy, and precision of these methods. This paper reports the evaluation of five methods using computer-assisted interactive graphics. Fifty cines were selected: 16 from normal subjects, and 34 from patients with proven cardiovascular diseases. Tracings were made of the opacified left ventricle in end systole and dastole and digitized. All fifty cines were analyzed by five methods using computer-implemented graphic techniques. The reults included a display of the silhouettes, which were translated and rotated according to various methods. In addition, the percent contraction for eleven myocardial regions was tabulated and displayed. The sixteen cines from normal subjects were used to derive 1 range of 'house' normal values for region contraction patterns with which the measurements from the 34 abnormal patients were compared. The five methods were evaluated by comparing results from the computer-aided analysis with the visual assessment of two experienced radiologists. One method was found, the results from which agreed with the radiologists' visual impression for every case. This computer-aided method was quantitative and reproducible. Consequently, it can give information which supplements the visual impression. (orig.) [de

  2. 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.

  3. Current induced domain wall motion and tilting in Pt/Co/Ta structures with perpendicular magnetic anisotropy in the presence of the Dyzaloshinskii–Moriya interaction

    Science.gov (United States)

    Yun, Jijun; Li, Dong; Cui, Baoshan; Guo, Xiaobin; Wu, Kai; Zhang, Xu; Wang, Yupei; Mao, Jian; Zuo, Yalu; Xi, Li

    2018-04-01

    Current induced domain wall motion (CIDWM) was studied in Pt/Co/Ta structures with perpendicular magnetic anisotropy and the Dyzaloshinskii–Moriya interaction (DMI) by the spin-orbit torque (SOT). We measured the strength of DMI and SOT efficiency in Pt/Co/Ta with the variation of the thickness of Ta using a current induced hysteresis loop shift method. The results indicate that the DMI stabilizes a chiral Néel-type domain wall (DW), and the DW motion can be driven by the enhanced large SOT generated from Pt and Ta with opposite signs of spin Hall angle in Pt/Co/Ta stacks. The CIDWM velocity, which is 104 times larger than the field driven DW velocity, obeys a creep law, and reaches around tens of meters per second with current density of ~106 A cm‑2. We also found that the Joule heating accompanied with current also accelerates the DW motion. Meanwhile, a domain wall tilting was observed, which increases with current density increasing. These results can be explained by the spin Hall effect generated from both heavy metals Pt and Ta, inherent DMI, and the current accompanying Joule heating effect. Our results could provide some new designing prospects to move multiple DWs by SOT for achieving racetrack memories.

  4. Evaluation of regional wall motion abnormalities of the heart. Comparison with Doppler tissue echocardiography, MR-tagging and levocardiography

    International Nuclear Information System (INIS)

    Kivelitz, D.E.; Enzweiler, C.N.H.; Hamm, B.; Borges, A.C.; Walde, T.; Rutsch, W.; Baumann, G.

    2004-01-01

    Purpose: To compare the visual analysis of magnetic resonance imaging (MRI) with the tagging technique and Doppler tissue echocardiography with invasive ventriculography in detecting and quantifying regional left ventricular wall motion abnormalities. Materials and Methods: Sixteen patients with coronary artery disease and a history of prior myocardial infarction underwent invasive ventriculography. Doppler tissue echocardiography and MR-tagging within one week. Regional wall motion abnormalities (WMA) were detected in all patients. WMA were graded as normal=1; hypokinetic=2; akinetic=3; or dyskinetic=4. For agreement between MRI, echocardiography, and ventriculography the kappa coefficient (κ) according to Cohen was calculated. Results: The kappa coefficient (κ) was 0.962 for agreement between MRI and echocardiography and 0.602 for agreement between MRI and ventriculography as well as between echocardiography and ventriculography. Conclusion: Reliable analysis of regional left ventricular wall motion abnormalities is feasible using visual analysis of MR-tagging. MRI and Doppler tissue echocardiography detect more WMA than invasive ventriculography and grade them as more severe. (orig.)

  5. Recovery of BMIPP uptake and regional wall motion in insulin resistant patients following angioplasty for acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Fujino, Takayuki; Ishii, Yoshinao; Hirasawa, Kunihiko; Tateda, Kunihiko [Asahikawa City Hospital, Hokkaido (Japan); Takeuchi, Toshiharu; Kikuchi, Kenjiro; Hasebe, Naoyuki [Asahikawa Medical Coll., Hokkaido (Japan)

    2003-09-01

    The effect of insulin resistance (IR) on the fatty acid metabolism of myocardium, and therefore on the recovery of left ventricular (LV) wall motion, has not been established in patients with acute myocardial infarction (AMI). A total of consecutive 58 non-diabetic AMI patients who had successfully undergone emergency coronary angioplasty were analyzed retrospectively. They were categorized into 2 groups, normal glucose tolerance (NGT) and impaired glucose tolerance (IGT), based on a 75-g oral glucose tolerance test (OGTT). The parameters of OGTT, myocardial scintigraphy (n=58) (thallium-201 (Tl) and iodine-123-{beta}-methyl-iodophenylpentadecanoic acid (BMIPP)) and left ventriculography (n=24) were compared in the 2 groups after reperfusion (acute phase) and 3-4 weeks after the AMI (chronic phase). The IR, estimated by the serum concentration of insulin at 120 min (IRI 120') of the OGTT and by the HOMA (the homeostasis model assessment) index, was higher in the IGT group than in NGT group. An inverse correlation was found between the recovery of regional LV wall motion in the ischemic lesion and the IRI 120' and HOMA index. Although the recovery of BMIPP uptake from the acute to the chronic phase was higher in the IGT group, it was only correlated with the degree of IRI 120', not with the HOMA. IR accompanied by IGT can negatively influence the recovery of regional LV wall motion. (author)

  6. Recovery of BMIPP uptake and regional wall motion in insulin resistant patients following angioplasty for acute myocardial infarction

    International Nuclear Information System (INIS)

    Fujino, Takayuki; Ishii, Yoshinao; Hirasawa, Kunihiko; Tateda, Kunihiko; Takeuchi, Toshiharu; Kikuchi, Kenjiro; Hasebe, Naoyuki

    2003-01-01

    The effect of insulin resistance (IR) on the fatty acid metabolism of myocardium, and therefore on the recovery of left ventricular (LV) wall motion, has not been established in patients with acute myocardial infarction (AMI). A total of consecutive 58 non-diabetic AMI patients who had successfully undergone emergency coronary angioplasty were analyzed retrospectively. They were categorized into 2 groups, normal glucose tolerance (NGT) and impaired glucose tolerance (IGT), based on a 75-g oral glucose tolerance test (OGTT). The parameters of OGTT, myocardial scintigraphy (n=58) (thallium-201 (Tl) and iodine-123-β-methyl-iodophenylpentadecanoic acid (BMIPP)) and left ventriculography (n=24) were compared in the 2 groups after reperfusion (acute phase) and 3-4 weeks after the AMI (chronic phase). The IR, estimated by the serum concentration of insulin at 120 min (IRI 120') of the OGTT and by the HOMA (the homeostasis model assessment) index, was higher in the IGT group than in NGT group. An inverse correlation was found between the recovery of regional LV wall motion in the ischemic lesion and the IRI 120' and HOMA index. Although the recovery of BMIPP uptake from the acute to the chronic phase was higher in the IGT group, it was only correlated with the degree of IRI 120', not with the HOMA. IR accompanied by IGT can negatively influence the recovery of regional LV wall motion. (author)

  7. Recovery of BMIPP uptake and regional wall motion in insulin resistant patients following angioplasty for acute myocardial infarction.

    Science.gov (United States)

    Fujino, Takayuki; Ishii, Yoshinao; Takeuchi, Toshiharu; Hirasawa, Kunihiko; Tateda, Kunihiko; Kikuchi, Kenjiro; Hasebe, Naoyuki

    2003-09-01

    The effect of insulin resistance (IR) on the fatty acid metabolism of myocardium, and therefore on the recovery of left ventricular (LV) wall motion, has not been established in patients with acute myocardial infarction (AMI). A total of consecutive 58 non-diabetic AMI patients who had successfully undergone emergency coronary angioplasty were analyzed retrospectively. They were categorized into 2 groups, normal glucose tolerance (NGT) and impaired glucose tolerance (IGT), based on a 75-g oral glucose tolerance test (OGTT). The parameters of OGTT, myocardial scintigraphy (n=58) (thallium-201 (Tl) and iodine-123-beta-methyl-iodophenylpentadecanoic acid (BMIPP)) and left ventriculography (n=24) were compared in the 2 groups after reperfusion (acute phase) and 3-4 weeks after the AMI (chronic phase). The insulin resistance (IR), estimated by the serum concentration of insulin at 120 min (IRI 120') of the OGTT and by the HOMA (the homeostasis model assessment) index, was higher in the IGT group than in NGT group. An inverse correlation was found between the recovery of regional LV wall motion in the ischemic lesion and the IRI 120' and HOMA index. Although the recovery of BMIPP uptake from the acute to the chronic phase was higher in the IGT group, it was only correlated with the degree of IRI 120', not with the HOMA. IR accompanied by IGT can negatively influence the recovery of regional LV wall motion.

  8. Prognostic value of high-dose dobutamine stress magnetic resonance imaging in 1,493 consecutive patients: assessment of myocardial wall motion and perfusion.

    Science.gov (United States)

    Korosoglou, Grigorios; Elhmidi, Yacine; Steen, Henning; Schellberg, Dieter; Riedle, Nina; Ahrens, Johannes; Lehrke, Stephanie; Merten, Constanze; Lossnitzer, Dirk; Radeleff, Jannis; Zugck, Christian; Giannitsis, Evangelos; Katus, Hugo A

    2010-10-05

    This study sought to determine the prognostic value of wall motion and perfusion assessment during high-dose dobutamine stress (DS) cardiac magnetic resonance imaging (MRI) in a large patient cohort. DS-MRI offers the possibility to integrate myocardial perfusion and wall motion analysis in a single examination for the detection of coronary artery disease (CAD). A total of 1,493 consecutive patients with suspected or known CAD underwent DS-MRI, using a standard protocol in a 1.5-T magnetic resonance scanner. Wall motion and perfusion were assessed at baseline and during stress, and outcome data including cardiac death, nonfatal myocardial infarction ("hard events"), and "late" revascularization performed >90 days after the MR scans were collected during a 2 ± 1 year follow-up period. Fifty-three hard events, including 14 cardiac deaths and 39 nonfatal infarctions, occurred during the follow-up period, whereas 85 patients underwent "late" revascularization. Using multivariable regression analysis, an abnormal result for wall motion or perfusion during stress yielded the strongest independent prognostic value for both hard events and late revascularization, clearly surpassing that of clinical and baseline magnetic resonance parameters (for wall motion: adjusted hazard ratio [HR] of 5.9 [95% confidence interval (CI): 2.5 to 13.6] for hard events and of 3.1 [95% CI: 1.7 to 5.6] for late revascularization, and for perfusion: adjusted HR of 5.4 [95% CI: 2.3 to 12.9] for hard events and of 6.2 [95% CI: 3.3 to 11.3] for late revascularization, p < 0.001 for all). DS-MRI can accurately identify patients who are at increased risk for cardiac death and myocardial infarction, separating them from those with normal findings, who have very low risk for future cardiac events. (Prognostic Value of High Dose Dobutamine Stress Magnetic Resonance Imaging; NCT00837005). Copyright © 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  9. Magneto-optical study of domain wall dynamics and giant Barkhausen jump in magnetic microwires

    International Nuclear Information System (INIS)

    Chizhik, A.; Zhukov, A.; Blanco, J.M.; Gonzalez, J.

    2012-01-01

    Investigation of surface domain walls motion in Co-rich magnetic microwires has been performed in circular and axial magnetic fields. The dc axial magnetic field acceleration of the domain wall motion related to the influence of the axial field on the structure of the moving domain wall has been discovered. Pulsed axial magnetic field induced unidirectional motion of surface domain wall also has been found.

  10. An automated four-point scale scoring of segmental wall motion in echocardiography using quantified parametric images

    International Nuclear Information System (INIS)

    Kachenoura, N; Delouche, A; Ruiz Dominguez, C; Frouin, F; Diebold, B; Nardi, O

    2010-01-01

    The aim of this paper is to develop an automated method which operates on echocardiographic dynamic loops for classifying the left ventricular regional wall motion (RWM) in a four-point scale. A non-selected group of 37 patients (2 and 4 chamber views) was studied. Each view was segmented according to the standardized segmentation using three manually positioned anatomical landmarks (the apex and the angles of the mitral annulus). The segmented data were analyzed by two independent experienced echocardiographists and the consensual RWM scores were used as a reference for comparisons. A fast and automatic parametric imaging method was used to compute and display as static color-coded parametric images both temporal and motion information contained in left ventricular dynamic echocardiograms. The amplitude and time parametric images were provided to a cardiologist for visual analysis of RWM and used for RWM quantification. A cross-validation method was applied to the segmental quantitative indices for classifying RWM in a four-point scale. A total of 518 segments were analyzed. Comparison between visual interpretation of parametric images and the reference reading resulted in an absolute agreement (Aa) of 66% and a relative agreement (Ra) of 96% and kappa (κ) coefficient of 0.61. Comparison of the automated RWM scoring against the same reference provided Aa = 64%, Ra = 96% and κ = 0.64 on the validation subset. Finally, linear regression analysis between the global quantitative index and global reference scores as well as ejection fraction resulted in correlations of 0.85 and 0.79. A new automated four-point scale scoring of RWM was developed and tested in a non-selected database. Its comparison against a consensual visual reading of dynamic echocardiograms showed its ability to classify RWM abnormalities.

  11. Domain wall and interphase boundary motion in (1−x)Bi(Mg{sub 0.5}Ti{sub 0.5})O{sub 3}–xPbTiO{sub 3} near the morphotropic phase boundary

    Energy Technology Data Exchange (ETDEWEB)

    Tutuncu, Goknur [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Chen, Jun; Fan, Longlong [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Fancher, Chris M.; Zhao, Jianwei [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Forrester, Jennifer S.; Jones, Jacob L., E-mail: JacobJones@ncsu.edu [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2016-07-28

    Electric field-induced changes in the domain wall motion of (1−x)Bi(Mg{sub 0.5}Ti{sub 0.5})O{sub 3}–xPbTiO{sub 3} (BMT-xPT) near the morphotropic phase boundary (MPB) where x = 0.37 (BMT-37PT) and x = 0.38 (BMT-38PT), are studied by means of synchrotron x-ray diffraction. Through Rietveld analysis and profile fitting, a mixture of coexisting monoclinic (Cm) and tetragonal (P4mm) phases is identified at room temperature. Extrinsic contributions to the property coefficients are evident from electric-field-induced domain wall motion in both the tetragonal and monoclinic phases, as well as through the interphase boundary motion between the two phases. Domain wall motion in the tetragonal and monoclinic phases for BMT-37PT is larger than that of BMT-38PT, possibly due to this composition's closer proximity to the MPB. Increased interphase boundary motion was also observed in BMT-37PT. Lattice strain, which is a function of both intrinsic piezoelectric strain and elastic interactions of the grains (the latter originating from domain wall and interphase boundary motion), is similar for the respective tetragonal and monoclinic phases.

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

    International Nuclear Information System (INIS)

    Lee, Jae Tae; Kim, Gwang Weon; Lee, Kyu Bo; Chung, Byung Chun; Whang, Kee Suk; Chae, Sung Chul; Paek, Wee Hyun; Cheon, Jae Eun; Lee, Hyong Woo; Chung, Jin Hong

    1990-01-01

    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.

  13. 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.

  14. Cardiac functional mapping for thallium-201 myocardial perfusion, washout, wall motion and phase using single-photon emission computed tomography (SPECT)

    International Nuclear Information System (INIS)

    Nakajima, Kenichi; Bunko, Hisashi; Taniguchi, Mitsuru; Taki, Junichi; Tonami, Norihisa; Hisada, Kinichi; Hirano, Takako; Wani, Hidenobu.

    1986-01-01

    A method for three-dimensional functional mapping of Tl-201 myocardial uptake, washout, wall motion and phase was developed using SPECT. Each parameter was mapped using polar display in the same format. Normal values were determined in Tl-201 exercise study in 16 patients. Myocardial counts were lower in the septum and inferior wall and the difference of counts between anterior and inferior walls were greater in man compared with the perfusion pattern in woman. Washout was slower at septum and inferior wall in man, and slightly slower at inferior wall in woman. In gated blood-pool tomography, length-based and count-based Fourier analyses were applied to calculate the parameters of contraction and phase. The results of both Fourier analyses generally agreed; however, the area of abnormality was slightly different. Phase maps were useful for the assessment of asynergy as well as in patients with conduction disorders. These cardiac functional maps using SPECT were considered to be effective for the understanding of three-dimensional informations of cardiac function. (author)

  15. Prediction of wall motion improvement after coronary revascularization in patients with postmyocardial infarction. Diagnostic value of dobutamine stress echocardiography and myocardial contrast echocardiography

    International Nuclear Information System (INIS)

    Waku, Sachiko; Ohkubo, Tomoyuki; Takada, Kiyoshi; Ishihara, Tadashi; Ohsawa, Nakaaki; Adachi, Itaru; Narabayashi, Isamu

    1997-01-01

    The diagnostic value of dobutamine stress echocardiography, myocardial contrast echocardiography and dipyridamole stress thallium-201 single photon emission computed tomography (SPECT) for predicting recovery of wall motion abnormality after revascularization was evaluated in 13 patients with postmyocardial infarction. Seventeen segments showed severe wall motion abnormalities before revascularization. Nine segments which had relatively good Tl uptake on delayed SPECT images despite severely abnormal wall motion were opacified during myocardial contrast echocardiography, and showed improved wall motion after revascularization. In contrast, three segments which had poor Tl uptake and severely abnormal wall motion were not opacified during myocardial contrast echocardiography, and showed no improvement in wall motion during dobutamine stress echocardiography and after revascularization. The following three findings were assumed to be signs of myocardial viability: good Tl uptake on delayed SPECT images, improved wall motion by dobutamine stress echocardiography, and positive opacification of the myocardium by myocardiai contrast echocardiography. Myocardial contrast echocardiography had the highest sensitivity (100%) and negative predictive value (100%). Delayed SPECT images had the highest specificity (100%) and positive predictive value (100%). Dobutamine stress echocardiography had a sensitivity of 83.0%, specificity of 80.0%, positive predictive value of 90.9%, and negative predictive value of 66.7%, respectively. Myocardial contrast echocardiography showed the lowest specificity (60.0%). The techniques of dobutamine stress echocardiography and SPECT, though noninvasive, may underestimate wall motion improvement after revascularization. Further examination by myocardial contrast echocardiography is recommended to assess myocardial viability for determining the indications for coronary revascularization in spite of its invasiveness. (author)

  16. Inertial Motion Capture Costume Design Study

    Directory of Open Access Journals (Sweden)

    Agnieszka Szczęsna

    2017-03-01

    Full Text Available The paper describes a scalable, wearable multi-sensor system for motion capture based on inertial measurement units (IMUs. Such a unit is composed of accelerometer, gyroscope and magnetometer. The final quality of an obtained motion arises from all the individual parts of the described system. The proposed system is a sequence of the following stages: sensor data acquisition, sensor orientation estimation, system calibration, pose estimation and data visualisation. The construction of the system’s architecture with the dataflow programming paradigm makes it easy to add, remove and replace the data processing steps. The modular architecture of the system allows an effortless introduction of a new sensor orientation estimation algorithms. The original contribution of the paper is the design study of the individual components used in the motion capture system. The two key steps of the system design are explored in this paper: the evaluation of sensors and algorithms for the orientation estimation. The three chosen algorithms have been implemented and investigated as part of the experiment. Due to the fact that the selection of the sensor has a significant impact on the final result, the sensor evaluation process is also explained and tested. The experimental results confirmed that the choice of sensor and orientation estimation algorithm affect the quality of the final results.

  17. 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.

  18. Investigation of domain wall motion in RE-TM magnetic wire towards a current driven memory and logic

    Energy Technology Data Exchange (ETDEWEB)

    Awano, Hiroyuki

    2015-06-01

    Current driven magnetic domain wall (DW) motions of ferri-magnetic TbFeCo wires have been investigated. In the case of a Si substrate, the critical current density (Jc) of DW motion was successfully reduced to 3×10{sup 6} A/cm{sup 2}. Moreover, by using a polycarbonate (PC) substrate with a molding groove of 600 nm width, the Jc was decreased to 6×10{sup 5} A/cm{sup 2}. In order to fabricate a logic in memory, a current driven spin logics (AND, OR, NOT) have been proposed and successfully demonstrated under the condition of low Jc. These results indicate that TbFeCo nanowire is an excellent candidate for next generation power saving memory and logic.

  19. MHD peristaltic motion of Johnson-Segalman fluid in a channel with compliant walls

    International Nuclear Information System (INIS)

    Hayat, T.; Javed, Maryiam; Asghar, S.

    2008-01-01

    A mathematical model for magnetohydrodynamic (MHD) flow of a Johnson-Segalman fluid in a channel with compliant walls is analyzed. The flow is engendered due to sinusoidal waves on the channel walls. A series solution is developed for the case in which the amplitude ratio is small. Our computations show that the mean axial velocity of a Johnson-Segalman fluid is smaller than that of a viscous fluid. The variations of various interesting dimensionless parameters are graphed and discussed

  20. Strain-Encoded Cardiac Magnetic Resonance Imaging as an Adjunct for Dobutamine Stress Testing. Incremental Value to Conventional Wall Motion Analysis

    Science.gov (United States)

    Korosoglou, Grigorios; Lossnitzer, Dirk; Schellberg, Dieter; Lewien, Antje; Wochele, Angela; Schaeufele, Tim; Neizel, Mirja; Steen, Henning; Giannitsis, Evangelos; Katus, Hugo A.; Osman, Nael F.

    2009-01-01

    Background High-dose dobutamine stress magnetic resonance imaging (DS-MRI) is safe and feasible for the diagnosis of coronary artery disease (CAD) in humans. However, the assessment of cine scans relies on the visual interpretation of regional wall motion, which is subjective. Recently, Strain-Encoded MRI (SENC) has been proposed for the direct color-coded visualization of myocardial strain. The purpose of our study was to compare the diagnostic value of SENC to that provided by conventional wall motion analysis for the detection of inducible ischemia during DS-MRI. Methods and Results Stress induced ischemia was assessed by wall motion analysis and by SENC in 101 patients with suspected or known CAD and in 17 healthy volunteers who underwent DS-MRI in a clinical 1.5T scanner. Quantitative coronary angiography deemed as the standard reference for the presence or absence of significant CAD (≥50% diameter stenosis). On a coronary vessel level, SENC detected inducible ischemia in 86/101 versus 71/101 diseased coronary vessels (p<0.01 versus cine), and showed normal strain response in 189/202 versus 194/202 vessels with <50% stenosis (p=NS versus cine). On a patient level, SENC detected inducible ischemia in 63/64 versus 55/64 patients with CAD (p<0.05 versus cine), and showed normal strain response in 32/37 versus 34/37 patients without CAD (p=NS versus cine).Quantification analysis demonstrated a significant correlation between strain rate reserve (SRreserve) and coronary artery stenosis severity (r²=0.56, p<0.001), and a cut-off value of SRreserve=1.64 deemed as a highly accurate marker for the detection of stenosis≥50% (AUC=0.96, SE=0.01, 95% CI = 0.94–0.98, p<0.001). Conclusions The direct color-coded visualization of strain on MR-images is a useful adjunct for DS-MRI, which provides incremental value for the detection of CAD compared to conventional wall motion readings on cine images. PMID:19808579

  1. 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.

  2. A Study of Aerodynamics in Kevlar-Wall Test Sections

    OpenAIRE

    Brown, Kenneth Alexander

    2014-01-01

    This study is undertaken to characterize the aerodynamic behavior of Kevlar-wall test sections and specifically those containing two-dimensional, lifting models. The performance of the Kevlar-wall test section can be evaluated against the standard of the hard-wall test section, which in the case of the Stability Wind Tunnel (SWT) at Virginia Tech can be alternately installed or replaced by the Kevlar-wall test section. As a first step towards the evaluation of the Kevlar-wall test section aer...

  3. The predictive value of 201Tl rest-redistribution and 18F-fluorodeoxyglucose SPECT for wall motion recovery after recent reperfused myocardial infarction.

    Science.gov (United States)

    González, Patricio; Massardo, Teresa; Coll, Claudia; Humeres, Pamela; Sierralta, Paulina; Jofré, M Josefina; Yovanovich, Jorge; Aramburu, Ivonne; Brugère, Solange; Chamorro, Hernán

    2004-04-01

    201Tl and 18F-FDG are useful for acute myocardial infarction (MI) assessment. The goal of this study was to compare their predictive value for wall motion recovery in the culprit area after a recent reperfused MI using SPECT technique. Forty-one patients (mean age: 56 +/- 12 years) were included, 81% of them male; all were studied within 1-24 days post MI. They underwent angioplasty in 27 cases (12 primary); bypass grafting in 10 cases and successful thrombolysis in 4. SPECT 201Tl injected at rest and redistribution (R-R) and also 18F-FDG, were performed on different days. Processed tomograms were interpreted blinded to clinical or angiographic data. Segmental wall motion assessed with echocardiography at baseline was compared with the 3 month follow up. Sensitivity [Confidence Interval] for 201Tl R-R was 74.6% [60.5-84.5], for FDG it was 82.1% [70.8-90.4]; specificities were 73% [64.3-80.5] and 54.8% [45.6-63.7], respectively. 18F-FDG tended to be more sensitive than 201Tl R-R, but the latter was more specific (p < 0.0004). Both 201Tl RR and 18F-FDG presented high negative predictive value (p: ns). In recent MI, SPECT 201Tl R-R is a valuable and widely available technique for viability detection, with similar sensitivity and significant better specificity than SPECT 18F-FDG.

  4. Importance of initial stress for abdominal aortic aneurysm wall motion: Dynamic MRI validated finite element analysis

    NARCIS (Netherlands)

    Merkx, M.A.G.; Veer, van 't M.; Speelman, L.; Breeuwer, M.; Buth, J.; Vosse, van de F.N.

    2009-01-01

    Currently the transverse diameter is the primary decision criterion to assess rupture risk in patients with an abdominal aortic aneurysm (AAA). To obtain a measure for more patient-specific risk assessment, aneurysm wall stress, calculated using finite element analysis (FEA), has been evaluated in

  5. Magneto-elastic resonant phenomena at the motion of the domain wall in weak ferromagnets

    International Nuclear Information System (INIS)

    Kuz'menko, A.P.; Zhukov, E.A.; Dobromyslov, M.B.; Kaminsky, A.V.

    2007-01-01

    Dynamics of domain walls (DWs) in transparent thin orthoferrite samples with weak ferromagnetic ordering is investigated at sub- and supersonic velocities. A resonant increase of Lamb waves and the formation of magnetoelastic solitons under resonant conditions in both an elastic and between a spin and elastic subsystems were observed

  6. Optical spin-transfer-torque-driven domain-wall motion in a ferromagnetic semiconductor

    Czech Academy of Sciences Publication Activity Database

    Ramsay, A.J.; Roy, P.E.; Haigh, J.A.; Otxoa, R.M.; Irvine, A.C.; Janda, T.; Campion, R. P.; Gallagher, B. L.; Wunderlich, Joerg

    2015-01-01

    Roč. 114, č. 6 (2015), "067202-1"-"067202-5" ISSN 0031-9007 R&D Projects: GA ČR GB14-37427G Institutional support: RVO:68378271 Keywords : magnetic domain walls * magneto-optics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.645, year: 2015

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

    DEFF Research Database (Denmark)

    Qi, P; Thomsen, C; Ståhlberg, F

    1993-01-01

    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...

  8. Assessment of cardiac performance with quantitative radionuclide angiocardiography: sequential left ventricular ejection fraction, normalized left ventricular ejection rate, and regional wall motion

    International Nuclear Information System (INIS)

    Marshall, R.C.; Berger, H.J.; Costin, J.C.; Freedman, G.S.; Wolberg, J.; Cohen, L.S.; Gotischalk, A.; Zaret, B.L.

    1977-01-01

    Sequential quantitative first pass radionuclide angiocardiograms (RA) were used to measure left ventricular ejection fraction (LVEF) and left ventricular ejection rate (LVER), and to assess regional wall motion (RWM) in the anterior (ANT) and left anterior oblique (LAO) positions. Studies were obtained with a computerized multicrystal scintillation camera suitable for acquiring high count-rate data. Background was determined in a new fashion by selecting frames temporally from the left ventricular region of interest time-activity curve. A ''representative'' cardiac cycle was formed by summing together counts over three to six cardiac cycles. From this background corrected, high count-rate ''representative''cardiac cycle, LVEF, LVER, and RWM were determined. In 22 patients with normal sinus rhythm in the absence of significant valvular regurgitation, RA LVEF correlated well with that measured by contrast angiography (r = 0.95). LVER correlated well with LVEF measured at contrast angiography (r = 0.90) and allowed complete separation of those with normal (LVER = 3.4 +- 0.17 sec -1 ) and abnormal (LVER = 1.22 +- 0.11 sec -1 ) (P < 0.001) left ventricular performance. This separation was independent of background. Isoproterenol infusion in five normal subjects caused LVER to increase by 81 +- 17% while LVEF increased by 10 +- 2.0%. RWM was correctly defined in 21/22 patients and 89% of left ventricular segments with abnormal wall motion

  9. Experiment and Simulation Study on the Amorphous Silicon Photovoltaic Walls

    Directory of Open Access Journals (Sweden)

    Wenjie Zhang

    2014-01-01

    Full Text Available Based on comparative study on two amorphous silicon photovoltaic walls (a-Si PV walls, the temperature distribution and the instant power were tested; and with EnergyPlus software, similar models of the walls were built to simulate annual power generation and air conditioning load. On typical sunshine day, the corresponding position temperature of nonventilated PV wall was generally 0.5~1.5°C higher than that of ventilated one, while the power generation was 0.2%~0.4% lower, which was consistent with the simulation results with a difference of 0.41% in annual energy output. As simulation results, in summer, comparing the PV walls with normal wall, the heat per unit area of these two photovoltaic walls was 5.25 kWh/m2 (nonventilated and 0.67 kWh/m2 (ventilated higher, respectively. But in winter the heat loss of nonventilated one was smaller, while ventilated PV wall was similar to normal wall. To annual energy consumption of heating and cooling, the building with ventilated PV wall and normal wall was also similar but slightly better than nonventilated one. Therefore, it is inferred that, at low latitudes, such as Zhuhai, China, air gap ventilation is suitable, while the length to thickness ratio of the air gap needs to be taken into account.

  10. Identification of microscopic domain wall motion from temperature dependence of nonlinear dielectric response.

    Czech Academy of Sciences Publication Activity Database

    Mokrý, Pavel; Sluka, T.

    2017-01-01

    Roč. 110, č. 16 (2017), č. článku 162906. ISSN 0003-6951 R&D Projects: GA ČR(CZ) GA14-32228S Institutional support: RVO:61389021 Keywords : microscopic domain wall * electric fields * temperature dependence Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Electrical and electronic engineering Impact factor: 3.411, year: 2016 http://dx.doi.org/10.1063/1.4981874

  11. Using Phun to Study "Perpetual Motion" Machines

    Science.gov (United States)

    Kores, Jaroslav

    2012-01-01

    The concept of "perpetual motion" has a long history. The Indian astronomer and mathematician Bhaskara II (12th century) was the first person to describe a perpetual motion (PM) machine. An example of a 13th-century PM machine is shown in Fig. 1. Although the law of conservation of energy clearly implies the impossibility of PM construction, over…

  12. Study of droplet flow in a T-shape microchannel with bottom wall fluctuation

    Science.gov (United States)

    Pang, Yan; Wang, Xiang; Liu, Zhaomiao

    2018-03-01

    Droplet generation in a T-shape microchannel, with a main channel width of 50 μm , side channel width of 25 μm, and height of 50 μm, is simulated to study the effects of the forced fluctuation of the bottom wall. The periodic fluctuations of the bottom wall are applied on the near junction part of the main channel in the T-shape microchannel. Effects of bottom wall's shape, fluctuation periods, and amplitudes on the droplet generation are covered in the research of this protocol. In the simulation, the average size is affected a little by the fluctuations, but significantly by the fixed shape of the deformed bottom wall, while the droplet size range is expanded by the fluctuations under most of the conditions. Droplet sizes are distributed in a periodic pattern with small amplitude along the relative time when the fluctuation is forced on the bottom wall near the T-junction, while the droplet emerging frequency is not varied by the fluctuation. The droplet velocity is varied by the bottom wall motion, especially under the shorter period and the larger amplitude. When the fluctuation period is similar to the droplet emerging period, the droplet size is as stable as the non-fluctuation case after a development stage at the beginning of flow, while the droplet velocity is varied by the moving wall with the scope up to 80% of the average velocity under the conditions of this investigation.

  13. Study on characteristics of vertical strong motions

    International Nuclear Information System (INIS)

    Akao, Y.; Katukura, H.; Fukushima, S.; Mizutani, M.

    1993-01-01

    Statistic properties of vertical strong ground motions from near-field earthquakes are discussed in comparison with that of horizontal motions. It is a feature of this analysis that time history of each observed record is divided into direct P- and S-wave segments from a seismological viewpoint. Following results are obtained. Vertical motion energy excited by direct S-waves is about 0.6 times of horizontal ones at deep underground, and it approaches to 1.0 at shallow place. Horizontal motion energy excited by direct P-waves becomes 0.2 times (at deep) or more (at shallow) of vertical one. These results can be available in modeling of input motions for aseismic design. (author)

  14. Magnetohydrodynamic peristaltic motion of a Newtonian fluid through porous walls through suction and injection

    Science.gov (United States)

    Sivaiah, R.; Hemadri Reddy, R.

    2017-11-01

    In this paper, we investigate the peristaltic transport of a conducting Newtonian fluid bounded by permeable walls with suction and injection moving with constant velocity of the wave in the wave frame of reference under the consideration of long wavelength and low Reynolds number. The analytical solution for the velocity field, pressure gradient and the frictional force are obtained. The effect of suction/injection parameter, amplitude ratio and the permeability parameter including slip on the flow quantities are discussed graphically. It is found that the greater the suction/injection parameter, the smaller the pressure rise against the pump works. Further, the pressure rise increases with increasing Magnetic parameter.

  15. Improved stage of infarction wall motion in AMI. Association between the presence or absence of mismatch in myocardial scintigrams of Tl and BMIPP and CK release pattern

    International Nuclear Information System (INIS)

    Kurihara, Masato; Abe, Masahiro; Abe, Toshihiro; Nagai, Yoshikazu; Ibukiyama, Chiharu

    1998-01-01

    Binuclear myocardial scintigraphy with BMIPP and 201 TlCl was conducted on 40 patients with myocardial infarction. In all of 40 patients, reperfusion therapy in the acute stage succeeded. The relationship between serum CK release pattern and timing of improvement of wall motion at infarct-related area in the chronic stage was investigated. The patients were divided into 3 groups according to the early or late appearance of peak CK, and the presence or absence of B type mismatch in dual myocardial scintigraphy with BMIPP and 201 TlCl obtained one month after acute onset of myocardial infarction. Infarct size obtained from 201 TlCl scintigraphy and wall motion related to infarction were also investigated immediately after reperfusion and one month thereafter, respectively. No differences were recognized between Group I, in which the infarct area had B type mismatch with early appearance of CK peak, and Group II, in which the infarct area also had B type mismatch with the late appearance of CK peak. Although the wall motion did not change at all in Group I, it improved in Group II one month after reperfusion. Group III did not demonstrate B type mismatch with late appearance of CK peak and smaller infarct size compared to those in Group I and Group II. The wall motion in Group III had a tendency to improve immediately after reperfusion and maintain that level one month later. The timing of improvement of wall motion after successful reperfusion in the area with B type mismatch was not uniform. This suggests that the nonuniformity of the timing of improvement of wall motion in the area with B type mismatch is partly attributable to some kinds of injury to myocardium caused by reperfusion. (author)

  16. 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.

  17. Current-driven domain wall motion based memory devices: Application to a ratchet ferromagnetic strip

    Science.gov (United States)

    Sánchez-Tejerina, Luis; Martínez, Eduardo; Raposo, Víctor; Alejos, Óscar

    2018-04-01

    Ratchet memories, where perpendicular magnetocristalline anisotropy is tailored so as to precisely control the magnetic transitions, has been recently proven to be a feasible device to store and manipulate data bits. For such devices, it has been shown that the current-driven regime of domain walls can improve their performances with respect to the field-driven one. However, the relaxing time required by the traveling domain walls constitutes a certain drawback if the former regime is considered, since it results in longer device latencies. In order to speed up the bit shifting procedure, it is demonstrated here that the application of a current of inverse polarity during the DW relaxing time may reduce such latencies. The reverse current must be sufficiently high as to drive the DW to the equilibrium position faster than the anisotropy slope itself, but with an amplitude sufficiently low as to avoid DW backward shifting. Alternatively, it is possible to use such a reverse current to increase the proper range of operation for a given relaxing time, i.e., the pair of values of the current amplitude and pulse time that ensures single DW jumps for a certain latency time.

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

    OpenAIRE

    Magalh?es, Cristiana M.; Fregonezi, Guilherme A.; Vidigal-Lopes, Mauro; Vieira, Bruna S. P. P.; Vieira, Danielle S. R.; Parreira, Ver?nica F.

    2016-01-01

    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...

  19. Current-induced domain wall motion in Ni{sub 80}Fe{sub 20} nanowires with low depinning fields

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, Gregory; Loerincz, Andreas; Krzyk, Stephen; Moehrke, Philipp; Bedau, Daniel; Boulle, Olivier; Rhensius, Jan; Klaeui, Mathias [Fachbereich Physik, Universitaet Konstanz, Universitaetsstrasse 10, D-78457 (Germany); Heyderman, Laura J [Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Cho, Young Jin; Seo, Sunae, E-mail: gregory.malinowski@uni-konstanz.d [Samsung Electronics, San 14-1 Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do (Korea, Republic of)

    2010-02-03

    In this paper, we report on domain wall (DW) motion induced by current pulses at variable temperature in 900 nm wide and 25 nm thick Ni{sub 80}Fe{sub 20} wires with low pinning fields. By using Ar ion milling to pattern our wires rather than the conventional lift-off technique, a depinning field as low as {approx}2-3 Oe at room temperature is obtained. Comparison with previous results acquired on similar wires with much higher pinning shows that the critical current density scales with the depinning field, leading to a critical current density of {approx}2.5 x 10{sup 11} A m{sup -2} at 250 K. Moreover, when a current pulse with a current density larger than the critical current density is injected, the DW is not necessarily depinned but it can undergo a modification of its spin structure which hinders current-induced DW motion. Hence, reliable propagation of the DW requires an accurate adjustment of the pulsed current density.

  20. Noninvasive detection of coronary artery wall thickening with age in healthy subjects using high resolution MRI with beat-to-beat respiratory motion correction.

    Science.gov (United States)

    Scott, Andrew D; Keegan, Jennifer; Mohiaddin, Raad H; Firmin, David N

    2011-10-01

    To demonstrate coronary artery wall thickening with age in a small healthy cohort using a highly efficient, reliable, and reproducible high-resolution MR technique. A 3D cross-sectional MR vessel wall images (0.7 × 0.7 × 3 mm resolution) with retrospective beat-to-beat respiratory motion correction (B2B-RMC) were obtained in the proximal right coronary artery of 21 healthy subjects (age, 22-62 years) with no known cardiovascular disease. Lumen and outer wall (lumen + vessel wall) areas were measured in one central slice from each subject and average wall thickness and wall area/outer wall area ratio (W/OW) calculated. Imaging was successful in 18 (86%) subjects with average respiratory efficiency 99.3 ± 1.7%. Coronary vessel wall thickness and W/OW significantly correlate with subject age, increasing by 0.088 mm and 0.031 per decade respectively (R = 0.53, P = 0.024 and R = 0.48, P = 0.046). No relationship was found between lumen area and vessel wall thickness (P = NS), but outer wall area increased significantly with vessel wall thickness at 19 mm(2) per mm (P = 0.046). This is consistent with outward vessel wall remodeling. Despite the small size of our healthy cohort, using high-resolution MR imaging and B2B-RMC, we have demonstrated increasing coronary vessel wall thickness and W/OW with age. The results obtained are consistent with outward vessel wall remodeling. Copyright © 2011 Wiley-Liss, Inc.

  1. Apollo 16 time and motion study

    Science.gov (United States)

    Kubis, J. F.; Elrod, J. T.; Rusnak, R.; Barnes, J. E.; Saxon, S. C.

    1972-01-01

    A time and motion study is presented of astronaut lunar surface activity on Apollo 16 which consists of five distinct analyses: an evaluation of lunar mobility, a comparison of task performance in 1-g training and lunar EVA, a study of metabolic costs and adaptation, a discussion of falls, and retrieval of fallen objects. Two basic mobility patterns, the hop or canter and the traditional walking gait, were consistently utilized in longer traverses. The metabolic rates associated with these two mobility types, each used by a different astronaut, were relatively equivalent. The time to perform tasks on the lunar surface was significantly longer (on the order of 70%) than the time to perform the same tasks during the last 1-g training session. These results corroborated the findings on Apollo 15 and were not significantly different from them. There was general improvement in lunar EVA performance upon repetition of tasks. Metabolic rate (BTU/hr.) and metabolic cost (BTU) decreased over successive EVAs. Specifically, the metabolic rate associated with riding the lunar roving vehicle (LRV) decreased by approximately 18% from EVA 1 to EVA 2 and by 15% from EVA 2 to EVA 3.

  2. Structural Studies of Complex Carbohydrates of Plant Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

    Darvill, Alan [Univ. of Georgia, Athens, GA (United States); Hahn, Michael G. [Univ. of Georgia, Athens, GA (United States); O' Neill, Malcolm A. [Univ. of Georgia, Athens, GA (United States); York, William S. [Univ. of Georgia, Athens, GA (United States)

    2015-02-17

    Most of the solar energy captured by land plants is converted into the polysaccharides (cellulose, hemicellulose, and pectin) that are the predominant components of the cell wall. These walls, which account for the bulk of plant biomass, have numerous roles in the growth and development of plants. Moreover, these walls have a major impact on human life as they are a renewable source of biomass, a source of diverse commercially useful polymers, a major component of wood, and a source of nutrition for humans and livestock. Thus, understanding the molecular mechanisms that lead to wall assembly and how cell walls and their component polysaccharides contribute to plant growth and development is essential to improve and extend the productivity and value of plant materials. The proposed research will develop and apply advanced analytical and immunological techniques to study specific changes in the structures and interactions of the hemicellulosic and pectic polysaccharides that occur during differentiation and in response to genetic modification and chemical treatments that affect wall biosynthesis. These new techniques will make it possible to accurately characterize minute amounts of cell wall polysaccharides so that subtle changes in structure that occur in individual cell types can be identified and correlated to the physiological or developmental state of the plant. Successful implementation of this research will reveal fundamental relationships between polysaccharide structure, cell wall architecture, and cell wall functions.

  3. Fungi and mites on humid indoor walls : a laboratory study

    NARCIS (Netherlands)

    Koren, L.G.H.; Kort, H.S.M.; Siebers, Rob; Cunningham, M.; Fitzharris, P.

    2000-01-01

    The potential allergen source formed by mites and fungi developing on walls has been studied in a semi-natural model. Gypsum and wooden pieces, representing indoor walls, were artificially soiled with one of two different organic compounds, a yeast/vegetable mixture (Mannite) or a red currant juice

  4. Apollo 15 time and motion study

    Science.gov (United States)

    Kubis, J. F.; Elrod, J. T.; Rusnak, R.; Barnes, J. E.

    1972-01-01

    A time and motion study of Apollo 15 lunar surface activity led to examination of four distinct areas of crewmen activity. These areas are: an analysis of lunar mobility, a comparative analysis of tasks performed in 1-g training and lunar EVA, an analysis of the metabolic cost of two activities that are performed in several EVAs, and a fall/near-fall analysis. An analysis of mobility showed that the crewmen used three basic mobility patterns (modified walk, hop, side step) while on the lunar surface. These mobility patterns were utilized as adaptive modes to compensate for the uneven terrain and varied soil conditions that the crewmen encountered. A comparison of the time required to perform tasks at the final 1-g lunar EVA training sessions and the time required to perform the same task on the lunar surface indicates that, in almost all cases, it took significantly more time (on the order of 40%) to perform tasks on the moon. This increased time was observed even after extraneous factors (e.g., hardware difficulties) were factored out.

  5. Paradoxical motion of interventricular septum on Tc-99m MIBI gated SPECT study

    International Nuclear Information System (INIS)

    Ergun, E.L.; Erbas, B.; Beylergil, V.; Demirturk, O.S.; Pasaoglu, I.

    2004-01-01

    After uncomplicated cardiac surgery, abnormal motion of the interventricular septum is frequently observed. The interventricular septum has often been found to display dyskinetic, or paradoxical motion by echocardiographic studies. This study was undertaken to describe instances of paradoxical motion of interventricular septum on Tc-99m MIBI gated SPECT studies in patients after coronary artery by pass graft surgery. Tc-99m MIBI gated SPECT in conjunction with stress myocardial perfusion SPECT was performed in 18 patients who had history of cardiac bypass graft surgery. Paradoxical motion of the interventricular septum was defined visually from Tc-99m MIBI gated SPECT. Perfusion of the interventricular septum was examined from myocardial perfusion images in the same study. Paradoxical motion of the interventricular septum was observed in 4 patients (22%). The interventricular septum was normally perfused in all patients. It was concluded that paradoxical motion of the interventricular septum in patients who had a history of cardiac by-pass graft surgery is not an uncommon finding and it can be observed with gated SPECT. The exact mechanism of this phenomenon is not well-known. A normal perfusion in interventricular wall helps to discriminate this situation from a real abnormality. (author)

  6. Semi-automatic detection and correction of body organ motion, particularly cardiac motion in SPECT studies

    International Nuclear Information System (INIS)

    Quintana, J.C.; Caceres, F.; Vargas, P.

    2002-01-01

    Aim: Detect patient motion during SPECT imaging. Material and Method: SPECT study is carried out on a patient's body organ, such as the heart, and frame of image data are thereby acquired. The image data in these frames are subjected to a series of mappings and computations, from which frame containing a significant quantity of organ motion can be identified. Quantification of motion occurs by shifting some of the mapped data within a predetermined range, and selecting that data shift which minimizes the magnitude of a motion sensitive mathematical function. The sensitive mathematical function is constructed from all set of image frames using the pixel data within a region covering the body organ. Using cine display of planar image data, the operator defines the working region by marking two points, which define two horizontal lines covering the area of the body organ. This is the only operator intervention. The mathematical function integrates pixel data from all set of image frames and therefore does not use derivatives which may cause distortion in noisy data. Moreover, as a global function, this method is superior than that using frame-to-frame cross-correlation function to identify motion between adjacent frames. Using standard image processing software, the method was implemented computationally. Ten SPECT studies with movement (Sestamibi cardiac studies and 99m-ECD brain SPECT studies) were selected plus two others with no movement. The acquisition SPECT protocol for the cardiac study was as follow: Step and shoot mode, non-circular orbit, 64 stops 20s each, 64x64x16 matrix and LEHR colimator. For the brain SPECT, 128 stops over 360 0 were used. Artificial vertical displacements (±1-2 pixels) over several frames were introduced in those studies with no movement to simulate patient motion. Results: The method was successfully tested in all cases and was capable to recognize SPECT studies with no body motion as well as those with body motion (both from the

  7. Wall-motion tracking in fetal echocardiography-Influence of frame rate on longitudinal strain analysis assessed by two-dimensional speckle tracking.

    Science.gov (United States)

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

    2017-06-01

    Frame rates (FR) used for strain analysis assessed by speckle tracking in fetal echocardiography show a considerable variation. The aim of this study was to investigate the influence of the FR on strain analysis in 2D speckle tracking. Fetal echocardiography was performed prospectively on a Toshiba Aplio 500 system and a Toshiba Artida system, respectively. Based on an apical or basal four-chamber view of the fetal heart, cine loops were stored with a FR of 30 fps (Aplio 500) and 60 fps (Artida/Aplio 500). For both groups (30fps and 60fps), global and segmental longitudinal peak systolic strain (LPSS) values of both, left (LV) and right ventricle (RV), were assessed by 2D wall-motion tracking. A total of 101 fetuses, distributed to three study groups, were included. The mean gestational age was 25.2±5.0 weeks. Mean global LPSS values for RV in the 30 fps group and in the 60 fps group were -16.07% and -16.47%, respectively. Mean global LPSS values for LV in the 30 fps group and in the 60 fps group were -17.54% and -17.06%, respectively. Comparing global and segmental LPSS values of both, the RV and LV, did not show any statistically significant differences within the two groups. Performance of myocardial 2D strain analysis by wall-motion tracking was feasible with 30 and 60 fps. Obtained global and segmental LPSS values of both ventricles were relatively independent from acquisition rate. © 2017, Wiley Periodicals, Inc.

  8. The experimental study of sinal wall thickening on CT

    International Nuclear Information System (INIS)

    Kase, Yasuhiro; Iinuma, Tositaka; Oyama, Kazuyuki.

    1988-01-01

    In our previous report, we investigated several factors which cause apparent thickening of the walls of maxillary sinus. We confirmed, however, that the major factor for the sinal wall thickening is the artifact of CT. In present study, we report the results obtained by phantom models of isolated maxillary bone and egg shell. As the substance corresponding to the soft tissue density, solutions of CaCl 2 in various concentrations were used. In the maxillary bone studies, the thickness of the anterior sinus wall by CT was larger than the actual value even though only the air was contained. When solutions of CaCl 2 were contained and in touch with the anterior wall, the thickness by CT was larger than that of containing air. In the egg shell studies, the increase in thickness by CT correlated to the increase in percentage of solutions. The above results indicate that the apparent increased thickness of the sinal walls by CT is largely the artifact by CT and is dependent upon the soft tissue density or CT value (X-ray attenuation coefficient) of substances in touch with the sinal walls. In CT images obtained by clinical cases, the increased thickness of the sinal walls, in sinuses filled with soft tissue density, is more apparent than real. (author)

  9. Using Phun to Study ``Perpetual Motion'' Machines

    Science.gov (United States)

    Koreš, Jaroslav

    2012-05-01

    The concept of "perpetual motion" has a long history. The Indian astronomer and mathematician Bhaskara II (12th century) was the first person to describe a perpetual motion (PM) machine. An example of a 13th- century PM machine is shown in Fig. 1. Although the law of conservation of energy clearly implies the impossibility of PM construction, over the centuries numerous proposals for PM have been made, involving ever more elements of modern science in their construction. It is possible to test a variety of PM machines in the classroom using a program called Phun2 or its commercial version Algodoo.3 The programs are designed to simulate physical processes and we can easily simulate mechanical machines using them. They provide an intuitive graphical environment controlled with a mouse; a programming language is not needed. This paper describes simulations of four different (supposed) PM machines.4

  10. Current-induced domain wall motion: Separating spin torque and Oersted-field effects in Co/Pt nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Heinen, Jan; Boulle, Olivier; Rousseau, Kevin; Malinowski, Gregory; Klaeui, Mathias [Universitaet Konstanz, Fachbereich Physik, D-78457 Konstanz (Germany); Swagton, Henk J.; Koopmans, Bert [Eindhoven University of Technology, Department of Applied Physics, MB 5600 (Netherlands); Ulysse, Christian; Faini, Giancarlo [CNRS, Phynano team, Laboratoire de Photonique et de Nanostructures, 91460 Marcoussis (France)

    2010-07-01

    We report on magnetotransport studies on perpendicularly magnetized nanowires with narrow domain wall (DW) structures. Using Co/Pt multilayer nanowires, we have previously shown that Joule heating is concealing most of the current induced domain wall effects, but using a constant sample temperature a large non-adiabacity factor {beta} has been deduced. Here, we carry out experiments for both applied field directions and current polarities, starting from different DW configurations within a Hall cross. We clearly show, using the different symmetries of spin torque and Oersted-field, that the much debated Oersted-field does not contribute to the DW depinning significantly. This allows us to extract the spin torque contribution and the non-adiabacity factor {beta}, which turns out to be in line with previous measurements.

  11. Studies on first wall and plasma wall interaction in JT-60

    International Nuclear Information System (INIS)

    Nakamura, Hiroo

    1988-12-01

    This paper describes studies on first wall and plasma wall interaction in JT-60. Main results are as follows; (1) To select JT-60 first wall material, various RandD were done in FY1975 ∼ 1976. Mo was selected as first wall materials of limiters and divertor plates because of its reliability under a high heat flux condition. (2) Development of low-Z material has been done to reduce impurity problem of Mo first wall. As a result, titanium carbide (TiC) was selected as a coating material on the Mo. High heat load testing has been done for TiC coated Mo limiter same as JT-60. This material can survive under the condition of 1 kW/cm 2 x 10 s, expected in JT-60 limiter design. (3) To reduce high heat load on the divertor plate, separatrix swing is proposed. Optimum frequency of the sweeping is evaluated to be 2 Hz in JT-60. For a discharge with heating power of 30 MW and duration time of 10 s, in addition to the separatrix swing, remote radiative cooling in the divertor region is necessary. Moreover, calculations of erosion thickness have been done for stainless steel, Mo, graphite, TiC and silicon caibide under high heat flux during plasma disruption. (4) In divertor experiments in JT-60, divertor functions on particle, heat load and impurity controls have been demonstrated. In elctron density of 6 x 10 19 m -3 , particle fueling rate of 20 MW NB heating (3 Pa m 3 /s) can be exhausted by divertor pumping system. Effectiveness of remote radiative cooling is demonstrated under the condition of 20 MW NB heating power. Also, separatrix swing is demonstrated to reduce heat load on the divertor plate. Total radiation in main plasma is 5 ∼ 10% of total absorbed power. (author) 120 refs

  12. Comprehensive Study of Plasma-Wall Sheath Transport Phenomena

    Science.gov (United States)

    2016-10-26

    the floating potential of wall material samples immersed in a low-temperature plasma were studied. Hysteresis is found to be due to secondary electron...continued research into plasma sheath physics. Hysteresis effects observed in the floating potential of wall material samples immersed in a low... Journal of Applied Physics, Volume 119, March 2016, pp. 113305 1-5. DISTRIBUTION A: Distribution approved for public release. 8 Figure 2

  13. Reversible wall motion abnormality on adenosine stress/rest thallium-201 gated myocardial SPECT is an independent predictor of coronary artery disease

    International Nuclear Information System (INIS)

    Park, Eun Kyung; Lee, Won Woo; So, Young; Eo, Jae Seon; Lee, Dong Soo; Chung, June Key; Lee, Myung Chul; Kim, Sang Eun; Kim, Cheol Ho; Lee, Sang Woo

    2004-01-01

    As early as 10 minutes after adenosine stress, immediate post-stress wall motion (ipsWM) can be evaluated on adenosine stress/rest TI-201 gated SPECT (gSPECT). To widen application of TI-201 in gated SPECT, we investigated image quality, LV parameters (EF, EDV, and ESV) reproducibility, and diagnostic competency of gSPECT regarding ipsWM evaluation Myocardial perfusion and wall motion were evaluated by 5-point scoring system in 20-segment model. Image quality was assessed using weighted Kappa (Kw) for inter-and intra-observer agreements of wall motion scores (n=49). Reproducibility was examined through repeated acquisition (n=31). Diagnostic competency was evaluated versus coronary angiography (CAG) and multivariate logistic regression analysis was performed to identify significant predictors of coronary artery disease (CAD) among stress abnormal perfusion (SSSp), stress abnormal wall motion (SSSwm), and reversible abnormal wall motion (SDSwm) (n=60). Kw for ipsWM was significantly better than that for rest regarding inter- (0.717 vs 0.489) and intra-observer agreements (0.792 vs 0.688) (p<0.05). 2SD for ipsWM was smaller than that for rest at EF (8.6% vs 10.7%) and ESV (6.0ml vs 8.4ml). Sensitivities of SSSp, SSSwm, and SDSwm were 63.3% (19/30), 63.3% (19/30), and 43.3% (13/30) and specificities 83.3% (25/30), 83.3% (25/30), and 86.7% (26/30), respectively. By multivariate analysis, SSSp (p=0.013) and SDSwm (p=0.039) remained significant predictors. Additionally, SSSwm or SDSwm could find undetected CAD in 54.5% (6/11) of patients with normal perfusion. TI-201 can be successfully applied to gated SPECT for ipsWM evaluation. Moreover, reversible wall motion abnormality on gSPECT is an independent predictor of significant CAD

  14. MOTION STUDY OF A WHEELCHAIR PROTOTYPE FOR DISABLED PEOPLE

    Directory of Open Access Journals (Sweden)

    Ionut GEONEA

    2015-05-01

    Full Text Available In this paper is presented the design and experimental prototype of a wheelchair for disabled people. Design solution proposed to be implemented uses two reduction gears motors and a mechanical transmission with chains. The motion controller developed uses PWM technology (pulse wave modulation. The wheelchair has the ability of forward – backward motion and steering. The design solution is developed in Solid Works, and it’s implemented to a wheelchair prototype model. Wheelchair design and motion makes him suitable especially for indoor use. It is made a study of the wheelchair kinematics, first using a kinematic simulation in Adams. Are presented the wheelchair motion trajectory and kinematics parameters. The experimental prototype is tested with a motion analysis system based on ultra high speed video recording. The obtained results from simulation and experimentally tests, demonstrate the efficiency of wheelchair proposed solution.

  15. Magnetic properties, domain-wall creep motion, and the Dzyaloshinskii-Moriya interaction in Pt/Co/Ir thin films

    Science.gov (United States)

    Shepley, Philippa M.; Tunnicliffe, Harry; Shahbazi, Kowsar; Burnell, Gavin; Moore, Thomas A.

    2018-04-01

    We study the magnetic properties of perpendicularly magnetized Pt/Co/Ir thin films and investigate the domain-wall creep method of determining the interfacial Dzyaloshinskii-Moriya (DM) interaction in ultrathin films. Measurements of the Co layer thickness dependence of saturation magnetization, perpendicular magnetic anisotropy, and symmetric and antisymmetric (i.e., DM) exchange energies in Pt/Co/Ir thin films have been made to determine the relationship between these properties. We discuss the measurement of the DM interaction by the expansion of a reverse domain in the domain-wall creep regime. We show how the creep parameters behave as a function of in-plane bias field and discuss the effects of domain-wall roughness on the measurement of the DM interaction by domain expansion. Whereas modifications to the creep law with DM field and in-plane bias fields have taken into account changes in the energy barrier scaling parameter α , we find that both α and the velocity scaling parameter v0 change as a function of in-plane bias field.

  16. Shock-tube study of fusion plasma-wall interactions

    International Nuclear Information System (INIS)

    Gross, R.A.; Tien, J.K.; Jensen, B.; Panayotou, N.F.; Feinberg, B.

    1977-01-01

    Theoretical and experimental studies have been made of phenomena which occur when a hot (T 1 approximately equal to 6 x 10 6 0 K), dense (n approximately equal to 10 16 cm -3 ), deuterium plasma containing a transverse magnetic field is brought into sudden contact with a cold metal wall. These studies are motivated by the need to understand plasma and metallurgical conditions at the first-wall of a fusion reactor. Experiments were carried out in the Columbia high energy electromagnetic shock tube. Computational simulation was used to investigate the detailed physics of the fusion plasma boundary layer which develops at the wall. The rate of energy transfer from the plasma to the wall was calculated and conditions under which surface melting occurs are estimated. Experimental measurements of plasma-wall heat transfer rates up to 3 x 10 5 watts/cm 2 were obtained and agreement with computed values are good. Fusion reactor first-wall materials have been exposed to 6.0 x 10 21 eV cm -2 (1,000 shots) of deuterium plasma bombardment. Scanning electron micrograph photographs show preferential erosion at grain boundaries, formation of deuterium surface blisters, and evidence of local surface melting. Some cracking is observed along grain boundaries, and a decrease in tensile ductiity is measured

  17. 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.

  18. Stress echocardiography with smartphone: real-time remote reading for regional wall motion.

    Science.gov (United States)

    Scali, Maria Chiara; de Azevedo Bellagamba, Clarissa Carmona; Ciampi, Quirino; Simova, Iana; de Castro E Silva Pretto, José Luis; Djordjevic-Dikic, Ana; Dodi, Claudio; Cortigiani, Lauro; Zagatina, Angela; Trambaiolo, Paolo; Torres, Marco R; Citro, Rodolfo; Colonna, Paolo; Paterni, Marco; Picano, Eugenio

    2017-11-01

    The diffusion of smart-phones offers access to the best remote expertise in stress echo (SE). To evaluate the reliability of SE based on smart-phone filming and reading. A set of 20 SE video-clips were read in random sequence with a multiple choice six-answer test by ten readers from five different countries (Italy, Brazil, Serbia, Bulgaria, Russia) of the "SE2020" study network. The gold standard to assess accuracy was a core-lab expert reader in agreement with angiographic verification (0 = wrong, 1 = right). The same set of 20 SE studies were read, in random order and >2 months apart, on desktop Workstation and via smartphones by ten remote readers. Image quality was graded from 1 = poor but readable, to 3 = excellent. Kappa (k) statistics was used to assess intra- and inter-observer agreement. The image quality was comparable in desktop workstation vs. smartphone (2.0 ± 0.5 vs. 2.4 ± 0.7, p = NS). The average reading time per case was similar for desktop versus smartphone (90 ± 39 vs. 82 ± 54 s, p = NS). The overall diagnostic accuracy of the ten readers was similar for desktop workstation vs. smartphone (84 vs. 91%, p = NS). Intra-observer agreement (desktop vs. smartphone) was good (k = 0.81 ± 0.14). Inter-observer agreement was good and similar via desktop or smartphone (k = 0.69 vs. k = 0.72, p = NS). The diagnostic accuracy and consistency of SE reading among certified readers was high and similar via desktop workstation or via smartphone.

  19. Analysis of the relationship between myocardial viability and regional left ventricular wall motion

    International Nuclear Information System (INIS)

    Furutani, Yuhji; Ozaki, Masaharu; Yamamoto, Takeshi; Sato, Shinichi; Saiki, Atsushi; Kusukawa, Reizo

    1993-01-01

    Myocardial viability was determined by using postsystolic shortening (PSS) as an index, as obtained by cardiac blood pool scintigraphy with Tc-99m HSA. The findings were compared with those of thallium-201 myocardial SPECT. The study population was comparised of 41 patients with single blood vessel disease in the left anterior descending artery (34 with old myocardial infarction and 7 with effort angina pectoris). Left ventricular area was divided into 6 segments, and global and regional left ventricular blood volume curves were obtained. Delayed end-systole was the most common in the apex (41%), followed by the upper septum (37%) and lower septum (10%). PSS resulting from delayed end-systole was seen in 36 areas. PSS/end-diastolic volume (EDV) and PSS/systolic volume (SV) were obtained by adjusting end-diastolic and stroke counts, respectively. Thallium-201 myocardial SPECT images were divided into 5 segments to obtain defect score (DS) for visual Tl uptake. Both PSS/EDV and PSS/SV were greater in association with more delayed end-systole, greater DS, and lower reginal ejection fraction. Areas showing greater PSS were associated with less myocardial viability, as observed on Tl myocardial SPECT images. Thus, PSS seemed to reflect the degree of myocardial necrosis within the region of interest. (N.K.)

  20. Ultrasonographic study of gallbladder wall thickness in acute viral hepatitis

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jin Sook; Kim, Kyung Jung; Park, Yang Hee; Kang, Ik Won; Yoon, Jong Sup [Hanyang Sacred Heart Hospital, Hallym University Medical Center, Seoul (Korea, Republic of)

    1984-09-15

    Prospective study of gallbladder wall thickness by ultrasonography was performed in 38 patients of acute viral hepatitis and 50 normal subjects as a control group from June 1983 to April 1984. The results were as follows; 1. In normal population, the range of gallbladder wall thickness is from 1 mm to 3 mm with peak incidence in 2 mm (66%, 33 case). Mean thickness of gallbladder wall is about 1.9 {+-} 0.6 mm. 2. In acute viral hepatitis, the range of gallbladder wall thickness is from 2 mm to 8 mm with peak incidence in 3 mm (34%, 13 case), second peak in 4 mm (29%, 11 case). Mean thickness of gallbladder wall is about 3.6 {+-} 1.6 mm, which is thicker than normal with statistical significance. (p<0.005) 3. In acute viral hepatitis, the mean thickness of gallbladder wall is about 4.4 {+-} 1.8 mm in the group of SGOT/SGPT level above 400 IU, and 2.8 {+-} 0.8 mm in the group of SGOT/ SGPT level below 400 IU. This difference is significant statistically. (p<0.05)

  1. Ultrasonographic study of gallbladder wall thickness in acute viral hepatitis

    International Nuclear Information System (INIS)

    Lim, Jin Sook; Kim, Kyung Jung; Park, Yang Hee; Kang, Ik Won; Yoon, Jong Sup

    1984-01-01

    Prospective study of gallbladder wall thickness by ultrasonography was performed in 38 patients of acute viral hepatitis and 50 normal subjects as a control group from June 1983 to April 1984. The results were as follows; 1. In normal population, the range of gallbladder wall thickness is from 1 mm to 3 mm with peak incidence in 2 mm (66%, 33 case). Mean thickness of gallbladder wall is about 1.9 ± 0.6 mm. 2. In acute viral hepatitis, the range of gallbladder wall thickness is from 2 mm to 8 mm with peak incidence in 3 mm (34%, 13 case), second peak in 4 mm (29%, 11 case). Mean thickness of gallbladder wall is about 3.6 ± 1.6 mm, which is thicker than normal with statistical significance. (p<0.005) 3. In acute viral hepatitis, the mean thickness of gallbladder wall is about 4.4 ± 1.8 mm in the group of SGOT/SGPT level above 400 IU, and 2.8 ± 0.8 mm in the group of SGOT/ SGPT level below 400 IU. This difference is significant statistically. (p<0.05)

  2. Domain Wall Formation in Ferromagnetic Layers: An Ab Initio Study

    Science.gov (United States)

    Herper, Heike C.

    Domain walls are an inherent feature of ferromagnetic (FM) films consisting of layers with different magnetic orientations. Since FM films are used in electrical devices the question of the influence of domain walls on, e.g., the magnetoresistance has attracted much interest. Besides discussing the resistance contribution of domain walls, it is appropriate to study different types of domain walls and their energy of formation. The behaviour of domain walls is usually discussed within model calculations. In the present paper it is done within an ab initio Green's function technique for layered systems, i.e., the fully relativistic, spin-polarized screened Korringa-Kohn Rostoker method. Results are presented for fcc Co layers covered by two semi-infinite fcc Pt(001) bulk systems or by bulk fcc Co(001), respectively. The resistance, which is caused by the different types of domain walls is discussed within a Kubo-Greenwood approach considering Co(001)/Co24/Co(001) as an example.

  3. Reversible Stress Cardiomyopathy Presenting as Acute Coronary Syndrome with Elevated Troponin in the Absence of Regional Wall Motion Abnormalities: A Forme Fruste of Stress Cardiomyopathy?

    Directory of Open Access Journals (Sweden)

    Mahesh Anantha Narayanan

    2014-01-01

    Full Text Available We present a case of reversible stress cardiomyopathy in a surgical patient, described here as a forme fruste due to its atypical features. It is important to recognize such unusual presentation of stress cardiomyopathy that mimics acute coronary syndrome. Stress cardiomyopathy commonly presents as acute coronary syndrome and is characterized by typical or atypical variants of regional wall motion abnormalities. We report a 60-year-old Caucasian male with reversible stress cardiomyopathy following a sternal fracture fixation. Although the patient had several typical features of stress cardiomyopathy including physical stress, ST-segment elevation, elevated cardiac biomarkers and normal epicardial coronaries, there were few features that were atypical, including unusual age, gender, absence of regional wall motion abnormalities, high lateral ST elevation, and high troponin-ejection fraction product. In conclusion, this could represent a forme fruste of stress cardiomyopathy.

  4. Identification of acute myocardial infarction with MR imaging by using combined assessment of regional wall motion and Gd-DTPA uptake

    International Nuclear Information System (INIS)

    Roos, A. de; Matheijssen, N.A.A.; Doornbos, J.; van Dijkman, P.; Pattynama, P.; van der Wall, E.

    1990-01-01

    This paper evaluates the usefulness of MR imaging for identification of acute myocardial infarction (AMI) in clinical patients, based on the assessment of regional wall motion abnormalities in conjunction with local uptake of Gd-DTPA. Fourteen patients with proved AMI and 12 normal volunteers underwent multisection-multiphase MR imaging in the short-axis plane encompassing the entire left ventricle. Gd-DTPA (0.2 mmol/kg) was injected in all patients to enhance the infarcted region. MR cine loops of the patients and volunteers were blinded and displayed. Three experienced observers scored the cine loops in consensus as to the presence or absence of AMI, noting wall motion abnormalities and/or increased Gd-DTPA uptake

  5. Study on Combustion Characteristics and Propelling Projectile Motion Process of Bulk-Loaded Liquid Propellant

    Science.gov (United States)

    Xue, Xiaochun; Yu, Yonggang; Mang, Shanshan

    2017-07-01

    Data are presented showing that the problem of gas-liquid interaction instability is an important subject in the combustion and the propellant projectile motion process of a bulk-loaded liquid propellant gun (BLPG). The instabilities themselves arise from the sources, including fluid motion, to form a combustion gas cavity called Taylor cavity, fluid turbulence and breakup caused by liquid motion relative to the combustion chamber walls, and liquid surface breakup arising from a velocity mismatch on the gas-liquid interface. Typically, small disturbances that arise early in the BLPG combustion interior ballistic cycle can become amplified in the absence of burn rate limiting characteristics. Herein, significant attention has been given to developing and emphasizing the need for better combustion repeatability in the BLPG. Based on this goal, the concept of using different geometries of the combustion chamber is introduced and the concept of using a stepped-wall structure on the combustion chamber itself as a useful means of exerting boundary control on the combustion evolution to thus restrain the combustion instability has been verified experimentally in this work. Moreover, based on this background, the numerical simulation is devoted to a special combustion issue under transient high-pressure and high-temperature conditions, namely, studying the combustion mechanism in a stepped-wall combustion chamber with full monopropellant on one end that is stationary and the other end can move at high speed. The numerical results also show that the burning surface of the liquid propellant can be defined geometrically and combustion is well behaved as ignition and combustion progressivity are in a suitable range during each stage in this combustion chamber with a stepped-wall structure.

  6. High-risk subgroup of inferior myocardial infarction. Importance of anterior wall motion and right ventricular function

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Tsunehiko; Yasuda, Tsunehiro; Gold, H K; Leinbach, R C; Boucher, C A; McKusick, K A; Strauss, H W

    1986-12-01

    To identify high-risk subgroups of inferior myocardial infarction, 75 patients presenting with their first inferior infarction were investigated by sequential gated blood pool scans. The patients were divided into four groups based on the right ventricular function (RVF) and anterior wall motion (AWM) of the left ventricle by scan at the time of admission. A second blood pool scan was performed at ten days to evaluate RV and LV function. Thirty-eight patients had cardiac catheterization before discharge and all patients were followed up for one year to determine their clinical outcome. Depressed RVF and reduced AWM were observed in 26 (35%) (Group A); depressed RVF and normal AWM were found in 20 (27%) (Group B); reduced AWM and normal RVE in 10 (13%) (Group C); and normal RVF and AWM in 19 (25%) (Group D). The mean values of biventricular function (LVEF, RVEF) in groups A, B, C, and D were (44.9 +- 8.4%, 32.5 +- 9.9%), (59.9 +- 8.6%, 34.5 +- 8.0%), (44.9 +- 15.7%, 48.2 +- 3.3%), and (60.4 +- 9.1%, 51.6 +- 10.6%), respectively, at admission. In serial measurements, LVEF did not change significantly in any group, however, RVEF improved nearly 10 points in groups A and B at 10 days. Group A also had the highest incidence (82 %) of left anterior descending coronary artery involvement, and the highest mean creatine phosphokinase levels (762 +- 318 U/1): Furthermore, group A had a high incidence of major complications during their hospital course and high mortality during the one-year follow-up. These data clearly identified group A as a high-risk subgroup of patients with inferior infarction.

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

    Science.gov (United States)

    Magalhães, Cristiana M; Fregonezi, Guilherme A; Vidigal-Lopes, Mauro; Vieira, Bruna S P P; Vieira, Danielle S R; Parreira, Verônica F

    2016-01-01

    The effects of non-invasive ventilation (NIV) on the breathing pattern and thoracoabdominal motion of patients with amyotrophic lateral sclerosis (ALS) are unknown. 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). 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. Chest wall volume increased significantly with NIV, mean volume=0.43 (SD=0.16)L versus 0.57 (SD=0.19)L (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=0.05)L/s versus 0.21 (SD=0.05)L/s (pNIV. 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). 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.

  8. 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.

  9. Numerical study of acoustophoretic motion of particles in a PDMS microchannel driven by surface acoustic waves.

    Science.gov (United States)

    Nama, Nitesh; Barnkob, Rune; Mao, Zhangming; Kähler, Christian J; Costanzo, Francesco; Huang, Tony Jun

    2015-06-21

    We present a numerical study of the acoustophoretic motion of particles suspended in a liquid-filled PDMS microchannel on a lithium niobate substrate acoustically driven by surface acoustic waves. We employ a perturbation approach where the flow variables are divided into first- and second-order fields. We use impedance boundary conditions to model the PDMS microchannel walls and we model the acoustic actuation by a displacement function from the literature based on a numerical study of piezoelectric actuation. Consistent with the type of actuation, the obtained first-order field is a horizontal standing wave that travels vertically from the actuated wall towards the upper PDMS wall. This is in contrast to what is observed in bulk acoustic wave devices. The first-order fields drive the acoustic streaming, as well as the time-averaged acoustic radiation force acting on suspended particles. We analyze the motion of suspended particles driven by the acoustic streaming drag and the radiation force. We examine a range of particle diameters to demonstrate the transition from streaming-drag-dominated acoustophoresis to radiation-force-dominated acoustophoresis. Finally, as an application of our numerical model, we demonstrate the capability to tune the position of the vertical pressure node along the channel width by tuning the phase difference between two incoming surface acoustic waves.

  10. Study on wall recycling behaviour in CPD spherical tokamak

    International Nuclear Information System (INIS)

    Bhattacharyay, R.; Zushi, H.; Hirooka, Y.; Sakamoto, M.; Yoshinaga, T.; Okamoto, K.; Kawasaki, S.; Hanada, K.; Sato, K.N.; Nakamura, K.; Idei, H.; Ryoukai, T.; Nakashima, H.; Higashijima, A.

    2008-01-01

    Experiments to study wall recycling behaviour have been performed in the small spherical tokamak compact plasma-wall interaction experimental device (CPD) from the viewpoint of global as well as local plasma wall interaction condition. Electron cyclotron resonance (ECR) plasma of typically ∼50 to 400 ms duration is produced using ∼40 to 80 kW RF power. In order to study the global wall recycling behaviour, pressure measurements are carried out just before and after the ECR plasma in the absence of any external pumping. The recycling behaviour is found to change from release to pumping beyond a certain level of pressure value which is again found to be a function of shot history. The real-time local wall behaviour is studied in similar RF plasma using a rotating tungsten limiter, actively coated with lithium. Measurement of H α light intensity in front of the rotating surface has indicated a clear reduction (∼10%) in the steady-state hydrogen recycling with continuous Li gettering of several minutes

  11. The value of regional wall motion abnormalities on 99Tcm-MIBI gated cardiac SPECT in predicting angiographic stenoses of coronary artery

    International Nuclear Information System (INIS)

    Li Dianfu; Huang Jun; Zhu Tiebing; Wang Liansheng; Yang Zhijian; Feng Jianlin; Li Jianhua; Chen Jianwei; Chang Guojun

    2004-01-01

    Objective: To determine the magnitude of angiographic stenoses of coronary artery in reversible regional wall motion abnormalities (RWMA) present in exercise stress 99 Tc m -methoxyisobutylisonitrile (MIBI) gated SPECT myocardial perfusion imaging (MPI). Methods: One hundred and sixteen patients undergoing coronary angiography two weeks before and after the exercise stress 99 Tc m -MIBI gated SPECT MPI. Images were acquired 15 to 20 min after stress. A five grades and twenty segments marking system was introduced to assess the RWMA and thickening of left ventricles. Results: The sensitivity of reversible RWMA for detecting ≥75% angiographic stenoses was 65%, with a specificity of 97%. Reversible RWMA has a high positive predictive value (98%) for stratification between severe angiographic stenoses of 75% and non-severe stenoses (less than 75%). Multivariate analysis showed that the post-stress wall motion (SSSWM), exercise wall motion differentiation value (SDSWM) and summed stress score (SSS) were the independent risk factor of coronary artery jeopardy score. Conclusions: Reversible RWMA, as shown by exercise stress 99 Tc m -MIBI gated SPECT MPI, is a significant predictor of angiographic disease with very high specificity and positive predictive values. Exercise reversible RWMA can rise the assessment value of angiographic severity in MPI

  12. 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.

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

    International Nuclear Information System (INIS)

    Zhmetko, D.N.; Zhmetko, S.D.; Troschenkov, Y.N.; Matsura, A.V.

    2013-01-01

    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

  14. Unmasking the mechanism of diffuse left ventricular wall motion abnormality in ischemic cardiomyopathy by resting-redistribution thallium-201 single photon computed tomography

    International Nuclear Information System (INIS)

    Namura, Hiroyuki; Yamabe, Hiroshi; Kakimoto, Tetsuya; Hashimoto, Yasunori; Yasaka, Yoshinori; Yoshida, Hiroaki; Itoh, Kazushi; Yokoyama, Mitsuhiro; Maeda, Kazumi.

    1992-01-01

    The study population comprised patients with ischemic cardiomyopathy (ICM) who had left ventricular wall motion (LVWM) abnormality in 5 or more segments (n=9), those with extensive myocardial infarction (EMI) having LVWM abnormality in 4 or less segments (n=12), and those with dilated left ventricle (DLV) having LVWM abnormality in all 7 segments (n=9). Defect scores (DS), obtained by initial and delayed Tl-201 myocardial single photon emission computed tomography at rest, were visually assessed to compare perfusion patterns in the three patient groups. The group of ICM patients had greater defect segments (DSeg) and % redistribution (Rd) index than the other two groups, although there was no difference in the number of angiographically proven infarct-related coronary vessels between EMI and ICM. In the group of ICM patients, there was inverse correlation not only between left ventricular ejection fraction and the sum of DS but also between left ventricular enddiastolic volume index and both the sum of DSeg and % Rd index. The group of DLV patients had small sum of DSeg and redistribution, compared with the other two groups. Although diffuse LVWM abnormality, as observed in the group of ICM patients, was considered attributable to potential decrease of coronary perfusion shown as defect on SPECT images, it did not always coincide with findings of coronary angiography. Both DSeg and redistribution phenomenon on SPECT images seemed to have the ability to evaluate the severity of ICM, as well as to differentiate ICM, EMI, and DLV. (N.K.)

  15. Study of noise reduction characteristics of double-wall panels

    Science.gov (United States)

    Navaneethan, R.; Quayle, B.; Stevenson, S.; Graham, M.

    1983-05-01

    The noise reduction characteristics of general aviation type, flat, double-wall structures were investigated. The experimental study was carried out on 20-by-20 inch panels with an exposed area of 18 by 18 inches. A frequency range from 20 to 5000 Hz was covered. The experimental results, in general, follow the expected trends. At low frequencies the double-wall structures are no better than the single-wall structures. However, for depths normally used in the general aviation industry, the double-wall panels are very attractive. The graphite-spoxy skin panels have higher noise reduction at very low frequencies ( 100 Hz) than the Kevlar skin panels. But the aluminum panels have higher noise reduction in the high frequency region, due to their greater mass. Use of fiberglass insulation is not effective in the low frequency region, and at times it is even negative. But the insulation is effective in the high-frequency region. The theoretical model for predicting the transmission loss of these multilayered panels is also discussed.

  16. Discrete Element study of granular material - Bumpy wall interface behavior

    Science.gov (United States)

    El Cheikh, Khadija; Rémond, Sébastien; Pizette, Patrick; Vanhove, Yannick; Djelal, Chafika

    2016-09-01

    This paper presents a DEM study of a confined granular material sheared between two parallel bumpy walls. The granular material consists of packed dry spherical particles. The bumpiness is modeled by spheres of a given diameter glued on horizontal planes. Different bumpy surfaces are modeled by varying diameter or concentration of glued spheres. The material is sheared by moving the two bumpy walls at fixed velocity. During shear, the confining pressure applied on each bumpy wall is controlled. The effect of wall bumpiness on the effective friction coefficient and on the granular material behavior at the bumpy walls is reported for various shearing conditions. For given bumpiness and confining pressure that we have studied, it is found that the shear velocity does not affect the shear stress. However, the effective friction coefficient and the behavior of the granular material depend on the bumpiness. When the diameter of the glued spheres is larger than about the average grains diameter of the medium, the latter is uniformly sheared and the effective friction coefficient remains constant. For smaller diameters of the glued spheres, the effective friction coefficient increases with the diameter of glued spheres. The influence of glued spheres concentration is significant only for small glued spheres diameters, typically half of average particle diameter of the granular material. In this case, increasing the concentration of glued spheres leads to a decrease in effective friction coefficient and to shear localization at the interface. For different diameters and concentrations of glued spheres, we show that the effect of bumpiness on the effective friction coefficient can be characterized by the depth of interlocking.

  17. Numerical study of fluid motion in bioreactor with two mixers

    Energy Technology Data Exchange (ETDEWEB)

    Zheleva, I., E-mail: izheleva@uni-ruse.bg [Department of Heat Technology, Hydraulics and Ecology, Angel Kanchev University of Rousse, 8 Studentska str., 7017 Rousse (Bulgaria); Lecheva, A., E-mail: alecheva@uni-ruse.bg [Department of Mathematics, Angel Kanchev University of Rousse, 8 Studentska str., 7017 Rousse (Bulgaria)

    2015-10-28

    Numerical study of hydrodynamic laminar behavior of a viscous fluid in bioreactor with multiple mixers is provided in the present paper. The reactor is equipped with two disk impellers. The fluid motion is studied in stream function-vorticity formulation. The calculations are made by a computer program, written in MATLAB. The fluid structure is described and numerical results are graphically presented and commented.

  18. Motion and time study analysis of wooden locally manufactured ...

    African Journals Online (AJOL)

    Studies were carried out on time-and-motion-economy of wooden locally manufactured duplicating machines. Two versions of the machine were used for the study, viz: standard version and semi-mechanized version. Working with both auxiliary and routine operations, the standard duplicator produced printed paper at an ...

  19. Apsidal Motion Study of Close Binary System CW Cephei

    Directory of Open Access Journals (Sweden)

    Wonyong Han

    2015-12-01

    Full Text Available New observations for the times of minimum lights of a well-known apsidal motion star CW Cephei were made using a 0.6 m wide field telescope at Jincheon station of Chungbuk National University Observatory, Korea during the 2015 observational season. We determined new times of minimum lights from these observations and analyzed O-C diagrams together with collected times of minima to study both the apsidal motion and the Light Time Effect (LTE suggested in the system. The new periods of the apsidal motion and the LTE were calculated as 46.6 and 39.3 years, respectively, which were similar but improved accuracy than earlier ones investigated by Han et al. (2002, Erdem et al. (2004 and Wolf et al. (2006.

  20. Association between proximal internal carotid artery steno-occlusive disease and diffuse wall thickening in its petrous segment: a magnetic resonance vessel wall imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaoyi; Li, Dongye [Capital Medical University and Beijing Institute for Brain Disorders, Center for Brain Disorders Research, Beijing (China); Tsinghua University School of Medicine, Center for Biomedical Imaging Research, Department of Biomedical Engineering, Beijing (China); Zhao, Huilin [Shanghai Jiao Tong University, Department of Radiology, Renji Hospital, School of Medicine, Shanghai (China); Chen, Zhensen; Qiao, Huiyu; He, Le; Li, Rui [Tsinghua University School of Medicine, Center for Biomedical Imaging Research, Department of Biomedical Engineering, Beijing (China); Cui, Yuanyuan [PLA General Hospital, Department of Radiology, Beijing (China); Zhou, Zechen [Philips Research China, Healthcare Department, Beijing (China); Yuan, Chun [Tsinghua University School of Medicine, Center for Biomedical Imaging Research, Department of Biomedical Engineering, Beijing (China); University of Washington, Department of Radiology, Seattle, WA (United States); Zhao, Xihai [Tsinghua University School of Medicine, Center for Biomedical Imaging Research, Department of Biomedical Engineering, Beijing (China); Beijing Institute for Brain Disorders, Center for Stroke, Beijing (China)

    2017-05-15

    Significant stenosis or occlusion in carotid arteries may lead to diffuse wall thickening (DWT) in the arterial wall of downstream. This study aimed to investigate the correlation between proximal internal carotid artery (ICA) steno-occlusive disease and DWT in ipsilateral petrous ICA. Symptomatic patients with atherosclerotic stenosis (>0%) in proximal ICA were recruited and underwent carotid MR vessel wall imaging. The 3D motion sensitized-driven equilibrium prepared rapid gradient-echo (3D-MERGE) was acquired for characterizing the wall thickness and longitudinal extent of the lesions in petrous ICA and the distance from proximal lesion to the petrous ICA. The stenosis degree in proximal ICA was measured on the time-of-flight (TOF) images. In total, 166 carotid arteries from 125 patients (mean age 61.0 ± 10.5 years, 99 males) were eligible for final analysis and 64 showed DWT in petrous ICAs. The prevalence of severe DWT in petrous ICA was 1.4%, 5.3%, 5.9%, and 80.4% in ipsilateral proximal ICAs with stenosis category of 1%-49%, 50%-69%, 70%-99%, and total occlusion, respectively. Proximal ICA stenosis was significantly correlated with the wall thickness in petrous ICA (r = 0.767, P < 0.001). Logistic regression analysis showed that proximal ICA stenosis was independently associated with DWT in ipsilateral petrous ICA (odds ratio (OR) = 2.459, 95% confidence interval (CI) 1.896-3.189, P < 0.001). Proximal ICA steno-occlusive disease is independently associated with DWT in ipsilateral petrous ICA. (orig.)

  1. Association between proximal internal carotid artery steno-occlusive disease and diffuse wall thickening in its petrous segment: a magnetic resonance vessel wall imaging study

    International Nuclear Information System (INIS)

    Chen, Xiaoyi; Li, Dongye; Zhao, Huilin; Chen, Zhensen; Qiao, Huiyu; He, Le; Li, Rui; Cui, Yuanyuan; Zhou, Zechen; Yuan, Chun; Zhao, Xihai

    2017-01-01

    Significant stenosis or occlusion in carotid arteries may lead to diffuse wall thickening (DWT) in the arterial wall of downstream. This study aimed to investigate the correlation between proximal internal carotid artery (ICA) steno-occlusive disease and DWT in ipsilateral petrous ICA. Symptomatic patients with atherosclerotic stenosis (>0%) in proximal ICA were recruited and underwent carotid MR vessel wall imaging. The 3D motion sensitized-driven equilibrium prepared rapid gradient-echo (3D-MERGE) was acquired for characterizing the wall thickness and longitudinal extent of the lesions in petrous ICA and the distance from proximal lesion to the petrous ICA. The stenosis degree in proximal ICA was measured on the time-of-flight (TOF) images. In total, 166 carotid arteries from 125 patients (mean age 61.0 ± 10.5 years, 99 males) were eligible for final analysis and 64 showed DWT in petrous ICAs. The prevalence of severe DWT in petrous ICA was 1.4%, 5.3%, 5.9%, and 80.4% in ipsilateral proximal ICAs with stenosis category of 1%-49%, 50%-69%, 70%-99%, and total occlusion, respectively. Proximal ICA stenosis was significantly correlated with the wall thickness in petrous ICA (r = 0.767, P < 0.001). Logistic regression analysis showed that proximal ICA stenosis was independently associated with DWT in ipsilateral petrous ICA (odds ratio (OR) = 2.459, 95% confidence interval (CI) 1.896-3.189, P < 0.001). Proximal ICA steno-occlusive disease is independently associated with DWT in ipsilateral petrous ICA. (orig.)

  2. High efficiency of the spin-orbit torques induced domain wall motion in asymmetric interfacial multilayered Tb/Co wires

    International Nuclear Information System (INIS)

    Bang, Do; Awano, Hiroyuki

    2015-01-01

    We investigated current-induced DW motion in asymmetric interfacial multilayered Tb/Co wires for various thicknesses of magnetic and Pt-capping layers. It is found that the driving mechanism for the DW motion changes from interfacial to bulk effects at much thick magnetic layer (up to 19.8 nm). In thin wires, linearly depinning field dependence of critical current density and in-plane field dependence of DW velocity suggest that the extrinsic pinning governs field-induced DW motion and injecting current can be regarded as an effective field. It is expected that the high efficiency of spin-orbit torques in thick magnetic multilayers would have important implication for future spintronic devices based on in-plane current induced-DW motion or switching

  3. High efficiency of the spin-orbit torques induced domain wall motion in asymmetric interfacial multilayered Tb/Co wires

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Do, E-mail: bang@spin.mp.es.osaka-u.ac.jp [Toyota Technological Institute, Tempaku, Nagoya 468-8511 (Japan); Institute of Materials Science, VAST, 18 Hoang Quoc Viet, Hanoi (Viet Nam); Awano, Hiroyuki [Toyota Technological Institute, Tempaku, Nagoya 468-8511 (Japan)

    2015-05-07

    We investigated current-induced DW motion in asymmetric interfacial multilayered Tb/Co wires for various thicknesses of magnetic and Pt-capping layers. It is found that the driving mechanism for the DW motion changes from interfacial to bulk effects at much thick magnetic layer (up to 19.8 nm). In thin wires, linearly depinning field dependence of critical current density and in-plane field dependence of DW velocity suggest that the extrinsic pinning governs field-induced DW motion and injecting current can be regarded as an effective field. It is expected that the high efficiency of spin-orbit torques in thick magnetic multilayers would have important implication for future spintronic devices based on in-plane current induced-DW motion or switching.

  4. Magnetic hysteresis scaling in thulium: Implication of irreversibility-related scaling for soliton wall motion in an Ising system

    International Nuclear Information System (INIS)

    Kobayashi, Satoru

    2013-01-01

    We report low-field magnetic hysteresis scaling in thulium with strong uniaxial anisotropy. A power-law hysteresis scaling with an exponent of 1.13±0.02 is found between hysteresis loss and remanent flux density of minor loops in the low-temperature ferrimagnetic phase. This exponent value is slightly lower than 1.25–1.4 observed previously for ferromagnets and helimagnets. Unlike spiral and/or Bloch walls with a finite transition width, typical for Dy, Tb, and Ho with planar anisotropy, a soliton wall with a sudden phase shift between neighboring domains may dominate in Tm due to its Ising-like character. The observations imply the presence of universality class of hysteresis scaling that depends on the type of magnetic anisotropy. - Highlights: ► We observe magnetic hysteresis scaling in thulium with a power law exponent of 1.13. ► Irreversibility of soliton walls dominates owing to its strong uniaxial anisotropy. ► The exponent is lower than those for Bloch wall and spiral wall. ► The results imply the presence of universality class that depends on the wall type.

  5. Study of wall conditioning in tokamaks with application to ITER

    International Nuclear Information System (INIS)

    Kogut, Dmitri

    2014-01-01

    Thesis is devoted to studies of performance and efficiency of wall conditioning techniques in fusion reactors, such as ITER. Conditioning is necessary to control the state of the surface of plasma facing components to ensure plasma initiation and performance. Conditioning and operation of the JET tokamak with ITER-relevant material mix is extensively studied. A 2D model of glow conditioning discharges is developed and validated; it predicts reasonably uniform discharges in ITER. In the nuclear phase of ITER operation conditioning will be needed to control tritium inventory. It is shown here that isotopic exchange is an efficient mean to eliminate tritium from the walls by replacing it with deuterium. Extrapolations for tritium removal are comparable with expected retention per a nominal plasma pulse in ITER. A 1D model of hydrogen isotopic exchange in beryllium is developed and validated. It shows that fluence and temperature of the surface influence efficiency of the isotopic exchange. (author) [fr

  6. Investigation of Plant Cell Wall Properties: A Study of Contributions from the Nanoscale to the Macroscale Impacting Cell Wall Recalcitrance

    Science.gov (United States)

    Crowe, Jacob Dillon

    Biochemical conversion of lignocellulosic biomass to fuel ethanol is one of a few challenging, yet opportune technologies that can reduce the consumption of petroleum-derived transportation fuels, while providing parallel reductions in greenhouse gas emissions. Biomass recalcitrance, or resistance to deconstruction, is a major technical challenge that limits effective conversion of biomass to fermentable sugars, often requiring a costly thermochemical pretreatment step to improve biomass deconstruction. Biomass recalcitrance is imparted largely by the secondary cell wall, a complex polymeric matrix of cell wall polysaccharides and aromatic heteropolymers, that provides structural stability to cells and enables plant upright growth. Polymers within the cell wall can vary both compositionally and structurally depending upon plant species and anatomical fraction, and have varied responses to thermochemical pretreatments. Cell wall properties impacting recalcitrance are still not well understood, and as a result, the goal of this dissertation is to investigate structural features of the cell wall contributing to recalcitrance (1) in diverse anatomical fractions of a single species, (2) in response to diverse pretreatments, and (3) resulting from genetic modification. In the first study, feedstock cell wall heterogeneity was investigated in anatomical (stem, leaf sheaths, and leaf blades) and internode fractions of switchgrass at varying tissue maturities. Lignin content was observed as the key contributor to recalcitrance in maturing stem tissues only, with non-cellulosic substituted glucuronoarabinoxylans and pectic polysaccharides contributing to cell wall recalcitrance in leaf sheath and leaf blades. Hydroxycinnamate (i.e., saponifiable p-coumarate and ferulate) content along with xylan and pectin extractability decreased with tissue maturity, suggesting lignification is only one component imparting maturity specific cell wall recalcitrance. In the second study

  7. Morphologic study of three collagen materials for body wall repair.

    Science.gov (United States)

    Soiderer, Emily E; Lantz, Gary C; Kazacos, Evelyn A; Hodde, Jason P; Wiegand, Ryan E

    2004-05-15

    The search for ideal prostheses for body wall repair continues. Synthetic materials such as polypropylene mesh (PPM) are associated with healing complications. A porcine-derived collagen-based material (CBM), small intestinal submucosa (SIS), has been studied for body wall repair. Renal capsule matrix (RCM) and urinary bladder submucosa (UBS) are CBMs not previously evaluated in this application. This is the first implant study using RCM. Full-thickness muscle/fascia ventral abdominal wall defects were repaired with SIS, RCM, UBS, and PPM in rats with omentum and omentectomy. A random complete block design was used to allot implant type to each of 96 rats. Healing was evaluated at 4 and 8 weeks. Adhesion tenacity and surface area were scored. Implant site dimensions were measured at implantation and necropsy. Inflammation, vascularization, and fibrosis were histopathologically scored. Data were compared by analysis of variance (P response in contrast to the organized healing of CBM implants. CBM mean scores were lower than PPM scores for adhesion tenacity, surface area, and inflammation at each follow-up time for rats with omentums (P fibrotic response to PPM was unique and more intense compared to CBMs. These CBM implants appear morphologically acceptable and warrant continued investigation.

  8. Chest wall syndrome among primary care patients: a cohort study

    Directory of Open Access Journals (Sweden)

    Verdon François

    2007-09-01

    Full Text Available Abstract Background The epidemiology of chest pain differs strongly between outpatient and emergency settings. In general practice, the most frequent cause is the chest wall pain. However, there is a lack of information about the characteristics of this syndrome. The aims of the study are to describe the clinical aspects of chest wall syndrome (CWS. Methods Prospective, observational, cohort study of patients attending 58 private practices over a five-week period from March to May 2001 with undifferentiated chest pain. During a one-year follow-up, questionnaires including detailed history and physical exam, were filled out at initial consultation, 3 and 12 months. The outcomes were: clinical characteristics associated with the CWS diagnosis and clinical evolution of the syndrome. Results Among 24 620 consultations, we observed 672 cases of chest pain and 300 (44.6% patients had a diagnosis of chest wall syndrome. It affected all ages with a sex ratio of 1:1. History and sensibility to palpation were the keys for diagnosis. Pain was generally moderate, well localised, continuous or intermittent over a number of hours to days or weeks, and amplified by position or movement. The pain however, may be acute. Eighty-eight patients were affected at several painful sites, and 210 patients at a single site, most frequently in the midline or a left-sided site. Pain was a cause of anxiety and cardiac concern, especially when acute. CWS coexisted with coronary disease in 19 and neoplasm in 6. Outcome at one year was favourable even though CWS recurred in half of patients. Conclusion CWS is common and benign, but leads to anxiety and recurred frequently. Because the majority of chest wall pain is left-sided, the possibility of coexistence with coronary disease needs careful consideration.

  9. Chest wall syndrome among primary care patients: a cohort study.

    Science.gov (United States)

    Verdon, François; Burnand, Bernard; Herzig, Lilli; Junod, Michel; Pécoud, Alain; Favrat, Bernard

    2007-09-12

    The epidemiology of chest pain differs strongly between outpatient and emergency settings. In general practice, the most frequent cause is the chest wall pain. However, there is a lack of information about the characteristics of this syndrome. The aims of the study are to describe the clinical aspects of chest wall syndrome (CWS). Prospective, observational, cohort study of patients attending 58 private practices over a five-week period from March to May 2001 with undifferentiated chest pain. During a one-year follow-up, questionnaires including detailed history and physical exam, were filled out at initial consultation, 3 and 12 months. The outcomes were: clinical characteristics associated with the CWS diagnosis and clinical evolution of the syndrome. Among 24 620 consultations, we observed 672 cases of chest pain and 300 (44.6%) patients had a diagnosis of chest wall syndrome. It affected all ages with a sex ratio of 1:1. History and sensibility to palpation were the keys for diagnosis. Pain was generally moderate, well localised, continuous or intermittent over a number of hours to days or weeks, and amplified by position or movement. The pain however, may be acute. Eighty-eight patients were affected at several painful sites, and 210 patients at a single site, most frequently in the midline or a left-sided site. Pain was a cause of anxiety and cardiac concern, especially when acute. CWS coexisted with coronary disease in 19 and neoplasm in 6. Outcome at one year was favourable even though CWS recurred in half of patients. CWS is common and benign, but leads to anxiety and recurred frequently. Because the majority of chest wall pain is left-sided, the possibility of coexistence with coronary disease needs careful consideration.

  10. Chest wall syndrome among primary care patients: a cohort study

    Science.gov (United States)

    Verdon, François; Burnand, Bernard; Herzig, Lilli; Junod, Michel; Pécoud, Alain; Favrat, Bernard

    2007-01-01

    Background The epidemiology of chest pain differs strongly between outpatient and emergency settings. In general practice, the most frequent cause is the chest wall pain. However, there is a lack of information about the characteristics of this syndrome. The aims of the study are to describe the clinical aspects of chest wall syndrome (CWS). Methods Prospective, observational, cohort study of patients attending 58 private practices over a five-week period from March to May 2001 with undifferentiated chest pain. During a one-year follow-up, questionnaires including detailed history and physical exam, were filled out at initial consultation, 3 and 12 months. The outcomes were: clinical characteristics associated with the CWS diagnosis and clinical evolution of the syndrome. Results Among 24 620 consultations, we observed 672 cases of chest pain and 300 (44.6%) patients had a diagnosis of chest wall syndrome. It affected all ages with a sex ratio of 1:1. History and sensibility to palpation were the keys for diagnosis. Pain was generally moderate, well localised, continuous or intermittent over a number of hours to days or weeks, and amplified by position or movement. The pain however, may be acute. Eighty-eight patients were affected at several painful sites, and 210 patients at a single site, most frequently in the midline or a left-sided site. Pain was a cause of anxiety and cardiac concern, especially when acute. CWS coexisted with coronary disease in 19 and neoplasm in 6. Outcome at one year was favourable even though CWS recurred in half of patients. Conclusion CWS is common and benign, but leads to anxiety and recurred frequently. Because the majority of chest wall pain is left-sided, the possibility of coexistence with coronary disease needs careful consideration. PMID:17850647

  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. Subterranean ground motion studies for the Einstein Telescope

    International Nuclear Information System (INIS)

    Beker, M G; Brand, J F J van den; Rabeling, D S

    2015-01-01

    Seismic motion limits the low-frequency sensitivity of ground-based gravitational wave detectors. A conceptual design study into the feasibility of a future-generation gravitational wave observatory, coined the Einstein Telescope, has been completed. As part of this design phase, we performed a ground motion study to determine the seismic noise characteristics at various sites across the globe. This investigation focused on underground sites and encompassed a variety of geologies, including clay, salt, and hard rock, at 15 locations in nine European countries, the USA, and Japan. In addition, we analyzed data from the Virtual European Broadband Seismograph Network to characterize European seismic motion. We show that, in the region of interest for future-generation gravitational wave detectors (1–10 Hz), seismic motion is dominated by activity from anthropogenic sources. A number of sites were found that exhibited a reduction in seismic power of several orders of magnitude with respect to current detector sites, thus making it possible to set requirements for the Einstein Telescope seismic noise environment. (paper)

  13. Coupled Cluster Studies of Ionization Potentials and Electron Affinities of Single-Walled Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Bo; Govind, Niranjan; Apra, Edoardo; Klemm, Michael; Hammond, Jeff R.; Kowalski, Karol

    2017-02-03

    In this paper we apply equation-of-motion coupled cluster (EOMCC) methods in studies of vertical ionization potentials (IP) and electron affinities (EA) for sin- gled walled carbon nanotubes. EOMCC formulations for ionization potentials and electron affinities employing excitation manifolds spanned by single and double ex- citations (IP/EA-EOMCCSD) are used to study IPs and EAs of nanotubes as a function of nanotube length. Several armchair nanotubes corresponding to C20nH20 models with n = 2 - 6 have been used in benchmark calculations. In agreement with previous studies, we demonstrate that the electronegativity of C20nH20 systems remains, to a large extent, independent of nanotube length. We also compare IP/EA- EOMCCSD results with those obtained with the coupled cluster models with single and double excitations corrected by perturbative triples, CCSD(T), and density func- tional theory (DFT) using global and range-separated hybrid exchange-correlation functionals.

  14. Geomagnetic field models for satellite angular motion studies

    Science.gov (United States)

    Ovchinnikov, M. Yu.; Penkov, V. I.; Roldugin, D. S.; Pichuzhkina, A. V.

    2018-03-01

    Four geomagnetic field models are discussed: IGRF, inclined, direct and simplified dipoles. Geomagnetic induction vector expressions are provided in different reference frames. Induction vector behavior is compared for different models. Models applicability for the analysis of satellite motion is studied from theoretical and engineering perspectives. Relevant satellite dynamics analysis cases using analytical and numerical techniques are provided. These cases demonstrate the benefit of a certain model for a specific dynamics study. Recommendations for models usage are summarized in the end.

  15. Experimental study of a shear wall with numerous small openings

    International Nuclear Information System (INIS)

    Sotomura, K.; Murazumi, Y.; Yoshizaki, S.; Ezaki, T.

    1981-01-01

    Many small openings for piping and ducts are usually required in the shear walls for PWR nuclear power plant. It is generally believed that such openings oadversely affect the strength and stiffness of shear walls. However, little information is available concerning the behavior of walls with numerous small openings. Therefore, tests using wall specimens and an analysis using an FEM program were carried out to investigate this behavior. Main findings are as follows: 1) The ultimate strength of a shear wall with numerous small openings may be obtained by using the effective area at the critical cross section of the shear wall. 2) Shear walls with openings can be restored to the same shear strength and stiffness as shear walls without openings by diagonal reinforcement. (orig./HP)

  16. Myocardial imaging with 99mTc-Tetrofosmin: Influence of post-stress acquisition time, regional radiotracer uptake, and wall motion abnormalities on the clinical result.

    Science.gov (United States)

    Giorgetti, Assuero; Kusch, Annette; Casagranda, Mirta; Tagliavia, Irene D'Aragona; Marzullo, Paolo

    2010-04-01

    We previously demonstrated that early (15', T1) post-stress myocardial imaging with Tetrofosmin could be more accurate than standard acquisitions (45', T2) in identifying coronary artery disease. To clarify this phenomenon, 120 subjects (age 61 +/- 10 years) with both T1 and T2 scans were divided into Group 1 (53/120 pts) with more ischemia at T1 vs T2 imaging (T1-T2SDS > or = 3); Group 2 (67/120 pts) with similar results (T1-T2SDS statistic and semiquantitative wall motion/thickening values were obtained. Analysis of T1 and T2 post-stress myocardial counts demonstrated a significant Tetrofosmin wash-out rate that was higher in Group 1 control nonischemic regions (15 +/- 8% vs 13.6 +/- 9.6%, P stress wall thickening (T1-T2) was lower in Group 1 ischemic regions (-4.5 +/- 9.15% vs -1.90 +/- 7.0%, P stress acquisition time because of ischemic-induced regional wall thickening abnormalities and the existence of a differential radiotracer myocardial wash-out.

  17. The Berlin Wall: A Simulation for the Social Studies Classroom

    Science.gov (United States)

    Russell, William B., III

    2010-01-01

    November 9, 2009, marked the twentieth anniversary of the opening of the Berlin Wall. The Wall, a symbol of the Cold War, separated the German people for 28 years (1961-1989), keeping those on the East side isolated. Although the construction and dismantling of the Berlin Wall is a significant part of history, the topic is little covered in the…

  18. Studying biomolecule localization by engineering bacterial cell wall curvature.

    Directory of Open Access Journals (Sweden)

    Lars D Renner

    Full Text Available In this article we describe two techniques for exploring the relationship between bacterial cell shape and the intracellular organization of proteins. First, we created microchannels in a layer of agarose to reshape live bacterial cells and predictably control their mean cell wall curvature, and quantified the influence of curvature on the localization and distribution of proteins in vivo. Second, we used agarose microchambers to reshape bacteria whose cell wall had been chemically and enzymatically removed. By combining microstructures with different geometries and fluorescence microscopy, we determined the relationship between bacterial shape and the localization for two different membrane-associated proteins: i the cell-shape related protein MreB of Escherichia coli, which is positioned along the long axis of the rod-shaped cell; and ii the negative curvature-sensing cell division protein DivIVA of Bacillus subtilis, which is positioned primarily at cell division sites. Our studies of intracellular organization in live cells of E. coli and B. subtilis demonstrate that MreB is largely excluded from areas of high negative curvature, whereas DivIVA localizes preferentially to regions of high negative curvature. These studies highlight a unique approach for studying the relationship between cell shape and intracellular organization in intact, live bacteria.

  19. Motion detection and correction for dynamic 15O-water myocardial perfusion PET studies

    International Nuclear Information System (INIS)

    Naum, Alexandru; Laaksonen, Marko S.; Oikonen, Vesa; Teraes, Mika; Jaervisalo, Mikko J.; Knuuti, Juhani; Tuunanen, Helena; Nuutila, Pirjo; Kemppainen, Jukka

    2005-01-01

    Patient motion during dynamic PET studies is a well-documented source of errors. The purpose of this study was to investigate the incidence of frame-to-frame motion in dynamic 15 O-water myocardial perfusion PET studies, to test the efficacy of motion correction methods and to study whether implementation of motion correction would have an impact on the perfusion results. We developed a motion detection procedure using external radioactive skin markers and frame-to-frame alignment. To evaluate motion, marker coordinates inside the field of view were determined in each frame for each study. The highest number of frames with identical spatial coordinates during the study were defined as ''non-moved''. Movement was considered present if even one marker changed position, by one pixel/frame compared with reference, in one axis, and such frames were defined as ''moved''. We tested manual, in-house-developed motion correction software and an automatic motion correction using a rigid body point model implemented in MIPAV (Medical Image Processing, Analysis and Visualisation) software. After motion correction, remaining motion was re-analysed. Myocardial blood flow (MBF) values were calculated for both non-corrected and motion-corrected datasets. At rest, patient motion was found in 18% of the frames, but during pharmacological stress the fraction increased to 45% and during physical exercise it rose to 80%. Both motion correction algorithms significantly decreased (p<0.006) the number of moved frames and the amplitude of motion (p<0.04). Motion correction significantly increased MBF results during bicycle exercise (p<0.02). At rest or during adenosine infusion, the motion correction had no significant effects on MBF values. Significant motion is a common phenomenon in dynamic cardiac studies during adenosine infusion but especially during exercise. Applying motion correction for the data acquired during exercise clearly changed the MBF results, indicating that motion

  20. Confirmation, refinement, and extension of a study in intrafraction motion interplay with sliding jaw motion

    International Nuclear Information System (INIS)

    Kissick, Michael W.; Boswell, Sarah A.; Jeraj, Robert; Mackie, T. Rockwell

    2005-01-01

    The interplay between a constant scan speed and intrafraction oscillatory motion produces interesting fluence intensity modulations along the axis of motion that are sensitive to the motion function, as originally shown in a classic paper by Yu et al. [Phys. Med. Biol. 43, 91-104 (1998)]. The fluence intensity profiles are explored in this note for an intuitive understanding, then compared with Yu et al., and finally further explored for the effects of low scan speed and random components of both intrafraction and interfraction motion. At slow scan speeds typical of helical tomotherapy, these fluence intensity modulations are only a few percent. With the addition of only a small amount of cycle-to-cycle randomness in frequency and amplitude, the fluence intensity profiles change dramatically. It is further shown that after a typical 30-fraction treatment, the sensitivities displayed in the single fraction fluence intensity profiles greatly diminish

  1. Feasibility study of patient motion monitoring using tactile array sensor

    International Nuclear Information System (INIS)

    Kim, Tae Ho; Kang, Seong Hee; Kim, Dong Su; Cho, Min Seok; Kim, Kyeong Hyeon; Suh, Tae Suk; Kim, Si Yong

    2014-01-01

    The aim of this study is to evaluate patient pretreatment set-up error and intra-fraction motion using the tactile array sensors (Pressure Profile Systems Inc, Los Angeles, CA) which could measure distributed pressure profiles along the contacting surface and to check a feasibility of the sensor (tactile array sensor) in the patient motion monitoring. Laser alignment and optical camera based monitoring system are very useful for reduce patient set-up error but these systems could not monitor the blind area like patient's back position. Actually after patient alignment using laser or optical monitoring system, it was assumed that there is no error in the patient's back position (pressure profile distribution). But if an error occurs in the patient's back position, it will affect the radiation therapy accuracy. In spite of optical motion monitoring or using the immobilization tool, distributed pressure profiles of patient's back position was changed during inter and intra-fraction. For more accurate patient set-up, blind area (patient's back) monitoring was necessary. We expect that the proposed method will be very useful for make up for the weakness of optical monitoring method

  2. Feasibility study of patient motion monitoring using tactile array sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Ho; Kang, Seong Hee; Kim, Dong Su; Cho, Min Seok; Kim, Kyeong Hyeon; Suh, Tae Suk [Dept. of Biomedical Engineering, Research Institute of Biomedical Engineering, the Catholic University of Korea, Seoul (Korea, Republic of); Kim, Si Yong [Dept. of Radiation Oncology, Virginia Commonwealth University, Richmond (United States)

    2014-11-15

    The aim of this study is to evaluate patient pretreatment set-up error and intra-fraction motion using the tactile array sensors (Pressure Profile Systems Inc, Los Angeles, CA) which could measure distributed pressure profiles along the contacting surface and to check a feasibility of the sensor (tactile array sensor) in the patient motion monitoring. Laser alignment and optical camera based monitoring system are very useful for reduce patient set-up error but these systems could not monitor the blind area like patient's back position. Actually after patient alignment using laser or optical monitoring system, it was assumed that there is no error in the patient's back position (pressure profile distribution). But if an error occurs in the patient's back position, it will affect the radiation therapy accuracy. In spite of optical motion monitoring or using the immobilization tool, distributed pressure profiles of patient's back position was changed during inter and intra-fraction. For more accurate patient set-up, blind area (patient's back) monitoring was necessary. We expect that the proposed method will be very useful for make up for the weakness of optical monitoring method.

  3. A study of solid wall models for weakly compressible SPH

    Energy Technology Data Exchange (ETDEWEB)

    Valizadeh, Alireza, E-mail: alireza.valizadeh@monash.edu [Department of Mechanical and Aerospace Engineering, Monash University, Clayton VIC 3800 (Australia); Monaghan, Joseph J., E-mail: joe.monaghan@monash.edu [School of Mathematical Sciences, Monash University, Clayton VIC 3800 (Australia)

    2015-11-01

    This paper is concerned with a comparison of two methods of treating solid wall boundaries in the weakly compressible (SPH) method. They have been chosen because of their wide use in simulations. These methods are the boundary force particles of Monaghan and Kajtar [24] and the use of layers of fixed boundary particles. The latter was first introduced by Morris et al. [26] but has since been improved by Adami et al. [1] whose algorithm involves interpolating the pressure and velocity from the actual fluid to the boundary particles. For each method, we study the effect of the density diffusive terms proposed by Molteni and Colagrossi [19] and modified by Antuono et al. [3]. We test the methods by a series of simulations commencing with the time-dependent spin-down of fluid within a cylinder and the behaviour of fluid in a box subjected to constant acceleration at an angle to the walls of the box, and concluding with a dam break over a triangular obstacle. In the first two cases the results from the two methods can be compared to analytical solutions while, in the latter case, they can be compared with experiments and other methods. These results show that the method of Adami et al. together with density diffusion is in very satisfactory agreement with the experimental results and is, overall, the best of the methods discussed here.

  4. Gravitational field of spherical domain wall in higher dimension

    Indian Academy of Sciences (India)

    An exact solution of Einstein's equations is found describing the gravitational field of a spherical domain wall with nonvanishing stress component in the direction perpendicular to the plane of the wall. Also we have studied the motion of test particle around the domain wall.

  5. Inhomogeneous nucleation and domain wall motion with Barkhausen avalanches in epitaxial PbZr0.4Ti0.6O3 thin films

    International Nuclear Information System (INIS)

    Yang, Sang Mo; Kim, Hun Ho; Kim, Tae Heon; Kim, Ik Joo; Yoon, Jong Gul

    2012-01-01

    We investigated the ferroelectric (FE) domain nucleation and domain wall motion in epitaxial PbZr 0.4 Ti 0.6 O 3 capacitors by using modified piezoresponse force microscopy with the domain-tracing method. From time-dependent FE domain evolution images, we observed that defect-mediated inhomogeneous nucleation occurred with a stochastic nature. In addition, we found that the number of nuclei N(t) was linearly proportional to log t, where t is the accumulated time of the applied pulse fields. The time-dependence of N(t) suggests a distribution of energy barriers for nucleation, which may determine the stochastic nature of domain nucleation. We also observed that the domain grew with consecutive Barkhausen avalanches and that the growth direction became anisotropic when the domain radius was larger than a critical radius of about 100 nm.

  6. Design studies of an aluminum first wall for INTOR

    International Nuclear Information System (INIS)

    Powell, J.R.; Fillo, J.A.; Yu, W.S.; Hsieh, S.Y.; Pearlman, H.; Kramer, R.; Franz, E.; Craig, A.; Farrell, K.

    1980-01-01

    Besides the high erosion rates (including evaporation) expected for INTOR, there may also be high heat fluxes to the first wall, e.g., approx. 9 (Case I) to 24 (Case II) W/cm 2 , from two sources - radiation and charge exchange neutrals. There will also be internal heat generation by neutron and gamma deposition. An aluminum first wall design is analyzed, which substantially reduces concerns about survivability of the first wall during INTOR's operating life

  7. Organ motion study and dosimetric impact of respiratory gating radiotherapy for esophageal cancer

    International Nuclear Information System (INIS)

    Lorchel, F.

    2007-04-01

    Chemoradiotherapy is now the standard treatment for locally advanced or inoperable esophageal carcinoma. In this indication, conformal radiotherapy is generally used. However, prognosis remains poor for these patients. Respiratory gating radiotherapy can decrease healthy tissues irradiation and allows escalation dose in lung, liver and breast cancer. In order to improve radiotherapy technique, we propose to study the feasibility of respiratory gating for esophageal cancer. We will study the respiratory motions of esophageal cancer to optimize target volume delineation, especially the internal margin (I.M.). We will test the correlation between tumour and chest wall displacements to prove that esophageal cancer motions are induced by respiration. This is essential before using free breathing respiratory gating systems. We will work out the dosimetric impact of respiratory gating using various dosimetric analysis parameters. We will compare dosimetric plans at end expiration, end inspiration and deep inspiration with dosimetric plan in free-breathing condition. This will allow us to establish the best respiratory phase to irradiate for each gating system. This dosimetric study will be completed with linear quadratic equivalent uniform dose (E.U.D.) calculation for each volume of interest. Previously, we will do a theoretical study of histogram dose volume gradation to point up its use. (author)

  8. Experimental Studies on Wave Interactions of Partially Perforated Wall under Obliquely Incident Waves

    Directory of Open Access Journals (Sweden)

    Jong-In Lee

    2014-01-01

    Full Text Available This study presents wave height distribution in terms of stem wave evolution phenomena on partially perforated wall structures through three-dimensional laboratory experiments. The plain and partially perforated walls were tested to understand their effects on the stem wave evolution under the monochromatic and random wave cases with the various wave conditions, incident angle (from 10 to 40 degrees, and configurations of front and side walls. The partially perforated wall reduced the relative wave heights more effectively compared to the plain wall structure. Partially perforated walls with side walls showed a better performance in terms of wave height reduction compared to the structure without the side wall. Moreover, the relative wave heights along the wall were relatively small when the relative chamber width is large, within the range of the chamber width in this study. The wave spectra showed a frequency dependency of the wave energy dissipation. In most cases, the existence of side wall is a more important factor than the porosity of the front wall in terms of the wave height reduction even if the partially perforated wall was still effective compared to the plain wall.

  9. Study of domain wall propagation in nanostructured CoPt multilayers by using antisymmetric magnetoresistance

    International Nuclear Information System (INIS)

    Rodriguez-Rodriguez, G; Perez-Junquera, A; Hierro-Rodriguez, A; Montenegro, N; Alameda, J M; Velez, M; Menendez, J L; Ravelosona, D

    2010-01-01

    Domain wall propagation has been studied in perpendicular anisotropy CoPt multilayers patterned by e-beam lithography into 5 μm wide wires. Positive and negative peaks appear in time resolved magnetoresistance curves, associated to the different directions of domain wall propagation along the wires. The field dependence of domain wall velocity is well described by a creep model of a 1D wall in the presence of weak disorder with critical exponent μ=1/4.

  10. A comparative study of near-wall turbulence in high and low Reynolds number boundary layers

    International Nuclear Information System (INIS)

    Metzger, M.M.; Klewicki, J.C.

    2001-01-01

    The present study explores the effects of Reynolds number, over three orders of magnitude, in the viscous wall region of a turbulent boundary layer. Complementary experiments were conducted both in the boundary layer wind tunnel at the University of Utah and in the atmospheric surface layer which flows over the salt flats of the Great Salt Lake Desert in western Utah. The Reynolds numbers, based on momentum deficit thickness, of the two flows were R θ =2x10 3 and R θ ≅5x10 6 , respectively. High-resolution velocity measurements were obtained from a five-element vertical rake of hot-wires spanning the buffer region. In both the low and high R θ flows, the length of the hot-wires measured less than 6 viscous units. To facilitate reliable comparisons, both the laboratory and field experiments employed the same instrumentation and procedures. Data indicate that, even in the immediate vicinity of the surface, strong influences from low-frequency motions at high R θ produce noticeable Reynolds number differences in the streamwise velocity and velocity gradient statistics. In particular, the peak value in the root mean square streamwise velocity profile, when normalized by viscous scales, was found to exhibit a logarithmic dependence on Reynolds number. The mean streamwise velocity profile, on the other hand, appears to be essentially independent of Reynolds number. Spectra and spatial correlation data suggest that low-frequency motions at high Reynolds number engender intensified local convection velocities which affect the structure of both the velocity and velocity gradient fields. Implications for turbulent production mechanisms and coherent motions in the buffer layer are discussed

  11. Fast switching and signature of efficient domain wall motion driven by spin-orbit torques in a perpendicular anisotropy magnetic insulator/Pt bilayer

    Science.gov (United States)

    Avci, Can Onur; Rosenberg, Ethan; Baumgartner, Manuel; Beran, Lukáš; Quindeau, Andy; Gambardella, Pietro; Ross, Caroline A.; Beach, Geoffrey S. D.

    2017-08-01

    We report fast and efficient current-induced switching of a perpendicular anisotropy magnetic insulator thulium iron garnet by using spin-orbit torques (SOT) from the Pt overlayer. We first show that, with quasi-DC (10 ms) current pulses, SOT-induced switching can be achieved with an external field as low as 2 Oe, making TmIG an outstanding candidate to realize efficient switching in heterostructures that produce moderate stray fields without requiring an external field. We then demonstrate deterministic switching with fast current pulses (≤20 ns) with an amplitude of ˜1012 A/m2, similar to all-metallic structures. We reveal that, in the presence of an initially nucleated domain, the critical switching current is reduced by up to a factor of five with respect to the fully saturated initial state, implying efficient current-driven domain wall motion in this system. Based on measurements with 2 ns-long pulses, we estimate the domain wall velocity of the order of ˜400 m/s per j = 1012 A/m2.

  12. Hydrodynamics of ultra-relativistic bubble walls

    Directory of Open Access Journals (Sweden)

    Leonardo Leitao

    2016-04-01

    Full Text Available In cosmological first-order phase transitions, gravitational waves are generated by the collisions of bubble walls and by the bulk motions caused in the fluid. A sizeable signal may result from fast-moving walls. In this work we study the hydrodynamics associated to the fastest propagation modes, namely, ultra-relativistic detonations and runaway solutions. We compute the energy injected by the phase transition into the fluid and the energy which accumulates in the bubble walls. We provide analytic approximations and fits as functions of the net force acting on the wall, which can be readily evaluated for specific models. We also study the back-reaction of hydrodynamics on the wall motion, and we discuss the extrapolation of the friction force away from the ultra-relativistic limit. We use these results to estimate the gravitational wave signal from detonations and runaway walls.

  13. Hydrodynamics of ultra-relativistic bubble walls

    Energy Technology Data Exchange (ETDEWEB)

    Leitao, Leonardo, E-mail: lleitao@mdp.edu.ar; Mégevand, Ariel, E-mail: megevand@mdp.edu.ar

    2016-04-15

    In cosmological first-order phase transitions, gravitational waves are generated by the collisions of bubble walls and by the bulk motions caused in the fluid. A sizeable signal may result from fast-moving walls. In this work we study the hydrodynamics associated to the fastest propagation modes, namely, ultra-relativistic detonations and runaway solutions. We compute the energy injected by the phase transition into the fluid and the energy which accumulates in the bubble walls. We provide analytic approximations and fits as functions of the net force acting on the wall, which can be readily evaluated for specific models. We also study the back-reaction of hydrodynamics on the wall motion, and we discuss the extrapolation of the friction force away from the ultra-relativistic limit. We use these results to estimate the gravitational wave signal from detonations and runaway walls.

  14. Vibrational motions in rotating nuclei studied by Coulomb excitations

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Yoshifumi R [Kyushu Univ., Fukuoka (Japan). Dept. of Physics

    1998-03-01

    As is well-known Coulomb excitation is an excellent tool to study the nuclear collective motions. Especially the vibrational excitations in rotating nuclei, which are rather difficult to access by usual heavy-ion fusion reactions, can be investigated in detail. Combined with the famous 8{pi}-Spectrometer, which was one of the best {gamma}-ray detector and had discovered some of superdeformed bands, such Coulomb excitation experiments had been carried out at Chalk River laboratory just before it`s shutdown of physics division. In this meeting some of the experimental data are presented and compared with the results of theoretical investigations. (author)

  15. Study of an active wall solar heating system

    International Nuclear Information System (INIS)

    Kassem, Talal

    2006-01-01

    An active wall solar heating system was built and tested. In the same time a compatible computer program has been according to set the recommended dimensions for the solar collectors where (F-Chart) method used to set the ratio of monthly solar sharing average for the examined heating system. Some parameters, such as collectors' areas, its tilt angle and near earth reflecting were experimentally investigated, affecting the executed active solar heating system performance. The study explain the ability of using this system which is simple, Low coast and high performance in heating residential and public buildings and heating water with ratio of yearly solar sharing achieves the needed saving of using this system.(Author)

  16. Sum frequency generation for studying plasma-wall interactions

    International Nuclear Information System (INIS)

    Roke, Sylvie

    2010-01-01

    Interaction of a plasma with a surface results in chemical and physical restructuring of the surface as well as the plasma in the vicinity of the surface. Studying such a reorganization of the atoms and molecules in the surface layer requires optical tools that can penetrate the plasma environment. At the same time, surface specificity is required. Sum Frequency Generation (SFG) is an optical method that fulfills these requirements. SFG has been developed into a surface specific probe during the eighties and nineties. Nowadays SFG is routinely applied in the research of complex interfaces. In such experiments, liquid/gas, solid/gas, solid/liquid, or liquid/liquid interfaces are probed, and the chemical surface composition, orientational distribution, order and chirality can be retrieved. An application to investigate plasma-wall interactions is feasible too.

  17. Neural Mechanisms of Illusory Motion: Evidence from ERP Study

    Directory of Open Access Journals (Sweden)

    Xu Y. A. N. Yun

    2011-05-01

    Full Text Available ERPs were used to examine the neural correlates of illusory motion, by presenting the Rice Wave illusion (CI, its two variants (WI and NI and a real motion video (RM. Results showed that: Firstly, RM elicited a more negative deflection than CI, NI and WI between 200–350ms. Secondly, between 500–600ms, CI elicited a more positive deflection than NI and WI, and RM elicited a more positive deflection than CI, what's more interesting was the sequential enhancement of brain activity with the corresponding motion strength. We inferred that the former component might reflect the successful encoding of the local motion signals in detectors at the lower stage; while the latter one might be involved in the intensive representations of visual input in real/illusory motion perception, this was the whole motion-signal organization in the later stage of motion perception. Finally, between 1185–1450 ms, a significant positive component was found between illusory/real motion tasks than NI (no motion. Overall, we demonstrated that there was a stronger deflection under the corresponding lager motion strength. These results reflected not only the different temporal patterns between illusory and real motion but also extending to their distinguishing working memory representation and storage.

  18. Sci-Fri PM: Radiation Therapy, Planning, Imaging, and Special Techniques - 11: Quantification of chest wall motion during deep inspiration breast hold treatments using cine EPID images and a physics based algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Alpuche Aviles, Jorge E.; VanBeek, Timothy [CancerCare Manitoba, Winnipeg (Canada); Sasaki, David; Rivest, Ryan; Akra, Mohamed [CancerCare Manitoba, Winnipeg (Canada); University of Manitoba, Winnipeg (Canada)

    2016-08-15

    Purpose: This work presents an algorithm used to quantify intra-fraction motion for patients treated using deep inspiration breath hold (DIBH). The algorithm quantifies the position of the chest wall in breast tangent fields using electronic portal images. Methods: The algorithm assumes that image profiles, taken along a direction perpendicular to the medial border of the field, follow a monotonically and smooth decreasing function. This assumption is invalid in the presence of lung and can be used to calculate chest wall position. The algorithm was validated by determining the position of the chest wall for varying field edge positions in portal images of a thoracic phantom. The algorithm was used to quantify intra-fraction motion in cine images for 7 patients treated with DIBH. Results: Phantom results show that changes in the distance between chest wall and field edge were accurate within 0.1 mm on average. For a fixed field edge, the algorithm calculates the position of the chest wall with a 0.2 mm standard deviation. Intra-fraction motion for DIBH patients was within 1 mm 91.4% of the time and within 1.5 mm 97.9% of the time. The maximum intra-fraction motion was 3.0 mm. Conclusions: A physics based algorithm was developed and can be used to quantify the position of chest wall irradiated in tangent portal images with an accuracy of 0.1 mm and precision of 0.6 mm. Intra-fraction motion for patients treated with DIBH at our clinic is less than 3 mm.

  19. The importance of stimulus noise analysis for self-motion studies.

    Directory of Open Access Journals (Sweden)

    Alessandro Nesti

    Full Text Available Motion simulators are widely employed in basic and applied research to study the neural mechanisms of perception and action during inertial stimulation. In these studies, uncontrolled simulator-introduced noise inevitably leads to a disparity between the reproduced motion and the trajectories meticulously designed by the experimenter, possibly resulting in undesired motion cues to the investigated system. Understanding actual simulator responses to different motion commands is therefore a crucial yet often underestimated step towards the interpretation of experimental results. In this work, we developed analysis methods based on signal processing techniques to quantify the noise in the actual motion, and its deterministic and stochastic components. Our methods allow comparisons between commanded and actual motion as well as between different actual motion profiles. A specific practical example from one of our studies is used to illustrate the methodologies and their relevance, but this does not detract from its general applicability. Analyses of the simulator's inertial recordings show direction-dependent noise and nonlinearity related to the command amplitude. The Signal-to-Noise Ratio is one order of magnitude higher for the larger motion amplitudes we tested, compared to the smaller motion amplitudes. Simulator-introduced noise is found to be primarily of deterministic nature, particularly for the stronger motion intensities. The effect of simulator noise on quantification of animal/human motion sensitivity is discussed. We conclude that accurate recording and characterization of executed simulator motion are a crucial prerequisite for the investigation of uncertainty in self-motion perception.

  20. Database for earthquake strong motion studies in Italy

    Science.gov (United States)

    Scasserra, G.; Stewart, J.P.; Kayen, R.E.; Lanzo, G.

    2009-01-01

    We describe an Italian database of strong ground motion recordings and databanks delineating conditions at the instrument sites and characteristics of the seismic sources. The strong motion database consists of 247 corrected recordings from 89 earthquakes and 101 recording stations. Uncorrected recordings were drawn from public web sites and processed on a record-by-record basis using a procedure utilized in the Next-Generation Attenuation (NGA) project to remove instrument resonances, minimize noise effects through low- and high-pass filtering, and baseline correction. The number of available uncorrected recordings was reduced by 52% (mostly because of s-triggers) to arrive at the 247 recordings in the database. The site databank includes for every recording site the surface geology, a measurement or estimate of average shear wave velocity in the upper 30 m (Vs30), and information on instrument housing. Of the 89 sites, 39 have on-site velocity measurements (17 of which were performed as part of this study using SASW techniques). For remaining sites, we estimate Vs30 based on measurements on similar geologic conditions where available. Where no local velocity measurements are available, correlations with surface geology are used. Source parameters are drawn from databanks maintained (and recently updated) by Istituto Nazionale di Geofisica e Vulcanologia and include hypocenter location and magnitude for small events (M< ??? 5.5) and finite source parameters for larger events. ?? 2009 A.S. Elnashai & N.N. Ambraseys.

  1. Computer-aided target tracking in motion analysis studies

    Science.gov (United States)

    Burdick, Dominic C.; Marcuse, M. L.; Mislan, J. D.

    1990-08-01

    Motion analysis studies require the precise tracking of reference objects in sequential scenes. In a typical situation, events of interest are captured at high frame rates using special cameras, and selected objects or targets are tracked on a frame by frame basis to provide necessary data for motion reconstruction. Tracking is usually done using manual methods which are slow and prone to error. A computer based image analysis system has been developed that performs tracking automatically. The objective of this work was to eliminate the bottleneck due to manual methods in high volume tracking applications such as the analysis of crash test films for the automotive industry. The system has proven to be successful in tracking standard fiducial targets and other objects in crash test scenes. Over 95 percent of target positions which could be located using manual methods can be tracked by the system, with a significant improvement in throughput over manual methods. Future work will focus on the tracking of clusters of targets and on tracking deformable objects such as airbags.

  2. Experimental study on concrete shear wall behavior under seismic loading

    International Nuclear Information System (INIS)

    Gantenbein, F.; Queval, J.C.; Epstein, A.; Dalbera, J.

    1991-01-01

    An experimental program has been undertaken on the dynamic behavior of shear walls with and without openings. The experimental set-up, the test program and the main results will be detailed in the paper

  3. Initial Ferritic Wall Mode studies on HBT-EP

    Science.gov (United States)

    Hughes, Paul; Bialek, J.; Boozer, A.; Mauel, M. E.; Levesque, J. P.; Navratil, G. A.

    2013-10-01

    Low-activation ferritic steels are leading material candidates for use in next-generation fusion development experiments such as a prospective US component test facility and DEMO. Understanding the interaction of plasmas with a ferromagnetic wall will provide crucial physics for these experiments. Although the ferritic wall mode (FWM) was seen in a linear machine, the FWM was not observed in JFT-2M, probably due to eddy current stabilization. Using its high-resolution magnetic diagnostics and positionable walls, HBT-EP has begun exploring the dynamics and stability of plasma interacting with high-permeability ferritic materials tiled to reduce eddy currents. We summarize a simple model for plasma-wall interaction in the presence of ferromagnetic material, describe the design of a recently-installed set of ferritic shell segments, and report initial results. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  4. Evaluation of composite shear walls behavior (parametric study

    Directory of Open Access Journals (Sweden)

    Ali Nikkhoo

    2017-11-01

    Full Text Available Composite shear walls which are made of a layer of steel plate with a concrete cover in one or both sides of the steel plate, are counted as the third generation of the shear walls. Nowadays, composite shear walls are widely utilized in building new resisting structures as well as rehabilitating of the existing structures in earthquake-prone countries. Despite of its advantages, use of the composite shear walls is not yet prevalent as it demands more detailed appropriate investigation. Serving higher strength, flexibility and better energy absorption, while being more economical are the main advantages of this system which has paved its path to be used in high-rise buildings, structural retrofit and reservoir tanks. In this research, channel shear connectors are utilized to connect the concrete cover to the steel plate. As a key parameter, variation in the distance of shear connectors and their arrangement on the behavior of composite shear walls has been scrutinized. In addition, the shear stiffness, flexibility, out of plane displacement and the energy absorption of the structural system has been explored. For this purpose, several structural models with different shear distances and arrangements have been investigated. The obtained results reveal that with increase in shear connectors’ distance, the wall stiffness would reduce while its lateral displacement increases up to eighty percent While the out of plane displacement of the steel plate will reduce up to three times.

  5. Functionalized molecules studied by STM: motion, switching and reactivity

    International Nuclear Information System (INIS)

    Grill, Leonhard

    2008-01-01

    Functionalized molecules represent the central issue of molecular nanotechnology. Scanning tunnelling microscopy (STM) is a powerful method to investigate such molecules, because it allows us to image them with sub-molecular resolution when adsorbed on a surface and can be used at the same time as a tool to manipulate single molecules in a controlled way. Such studies permit deep insight into the conformational, mechanical and electronic structure and thus functionalities of the molecules. In this review, recent experiments on specially designed molecules, acting as model systems for molecular nanotechnology, are reviewed. The presented studies focus on key functionalities: lateral rolling and hopping motion on a supporting surface, the switching behaviour of azobenzene derivatives by using the STM tip and the controlled reactivity of molecular side groups, which enable the formation of covalently bound molecular nanoarchitectures. (topical review)

  6. Study of Hygrothermal Processes in External Walls with Internal Insulation

    Directory of Open Access Journals (Sweden)

    Biseniece Edite

    2018-03-01

    Full Text Available Being an important contributor to the final energy consumption, historic buildings built before 1945 have high specific heating energy consumption compared to current energy standards and norms. However, they often cannot be insulated from the outside due to their heritage and culture value. Internal insulation is an alternative. However internal insulation faces challenges related to hygrothermal behaviour leading to mold growth, freezing, deterioration and other risks. The goal of this research is to link hygrothermal simulation results with experimental results for internally insulated historic brick masonry to assess correlation between simulated and measured data as well as the most influential parameters. The study is carried out by both a mathematical simulation tool and laboratory tests of historic masonry with internal insulation with four insulation materials (mineral wool, EPS, wood fiber and granulated aerogel in a cold climate (average 4000 heating degree days. We found disparity between measured and simulated hygrothermal performance of studied constructions due to differences in material parameters and initial conditions of materials. The latter plays a more important role than material parameters. Under a steady state of conditions, the condensate tolerating system varies between 72.7 % and 80.5 % relative humidity, but in condensate limiting systems relative humidity variates between 73.3 % and 82.3 %. The temperature between the masonry wall and all insulation materials has stabilized on average at +10 °C. Mold corresponding to Mold index 3 was discovered on wood fiber mat.

  7. Study of Hygrothermal Processes in External Walls with Internal Insulation

    Science.gov (United States)

    Biseniece, Edite; Freimanis, Ritvars; Purvins, Reinis; Gravelsins, Armands; Pumpurs, Aivars; Blumberga, Andra

    2018-03-01

    Being an important contributor to the final energy consumption, historic buildings built before 1945 have high specific heating energy consumption compared to current energy standards and norms. However, they often cannot be insulated from the outside due to their heritage and culture value. Internal insulation is an alternative. However internal insulation faces challenges related to hygrothermal behaviour leading to mold growth, freezing, deterioration and other risks. The goal of this research is to link hygrothermal simulation results with experimental results for internally insulated historic brick masonry to assess correlation between simulated and measured data as well as the most influential parameters. The study is carried out by both a mathematical simulation tool and laboratory tests of historic masonry with internal insulation with four insulation materials (mineral wool, EPS, wood fiber and granulated aerogel) in a cold climate (average 4000 heating degree days). We found disparity between measured and simulated hygrothermal performance of studied constructions due to differences in material parameters and initial conditions of materials. The latter plays a more important role than material parameters. Under a steady state of conditions, the condensate tolerating system varies between 72.7 % and 80.5 % relative humidity, but in condensate limiting systems relative humidity variates between 73.3 % and 82.3 %. The temperature between the masonry wall and all insulation materials has stabilized on average at +10 °C. Mold corresponding to Mold index 3 was discovered on wood fiber mat.

  8. Free-breathing black-blood CINE fast-spin echo imaging for measuring abdominal aortic wall distensibility: a feasibility study

    Science.gov (United States)

    Lin, Jyh-Miin; Patterson, Andrew J.; Chao, Tzu-Cheng; Zhu, Chengcheng; Chang, Hing-Chiu; Mendes, Jason; Chung, Hsiao-Wen; Gillard, Jonathan H.; Graves, Martin J.

    2017-05-01

    The paper reports a free-breathing black-blood CINE fast-spin echo (FSE) technique for measuring abdominal aortic wall motion. The free-breathing CINE FSE includes the following MR techniques: (1) variable-density sampling with fast iterative reconstruction; (2) inner-volume imaging; and (3) a blood-suppression preparation pulse. The proposed technique was evaluated in eight healthy subjects. The inner-volume imaging significantly reduced the intraluminal artifacts of respiratory motion (p  =  0.015). The quantitative measurements were a diameter of 16.3  ±  2.8 mm and wall distensibility of 2.0  ±  0.4 mm (12.5  ±  3.4%) and 0.7  ±  0.3 mm (4.1  ±  1.0%) for the anterior and posterior walls, respectively. The cyclic cross-sectional distensibility was 35  ±  15% greater in the systolic phase than in the diastolic phase. In conclusion, we developed a feasible CINE FSE method to measure the motion of the abdominal aortic wall, which will enable clinical scientists to study the elasticity of the abdominal aorta.

  9. Prediction of improvement of myocardial wall motion after coronary artery bypass surgery using rest Tl-201/dipyridamole stress gated Tc-99m-MIBI/24 hour delay Tl-201 SPECT

    International Nuclear Information System (INIS)

    Lee, Dong Soo; Lee, Won Woo; Yeo, Jeong Yeo; Kim, Seok Ki; Kim, Ki Bong; Chung, June Key; Lee, Myung Chul

    1998-01-01

    Using rest Tl-201/ dipyridamole stress gated Tc-99m-MIBI/24 hour delay Tl-201 SPECT, we investigated the predictive values of the markers of the stress-rest reversibility (Rev), Tl-201 rest perfusion (Rest), Tl-201 24 hour redistribution (Del) and Tc-99m-MIBI gated systolic thickening (Thk) for wall motion improvement after coronary artery bypass surgery. In 39 patients (M:F=34:5, age 58±8), preoperative and postoperative (3 months) SPECT were compared. 24 hour delayed SPECT was done in 16 patients having perfusion defects at rest. Perfusion or wall motion was scored from 0 to 3 (0: normal to 3: defect or dyskinesia). Wall motion was abnormal in 142 segments among 585 segments of 99 artery territories which were surgically revascularized. After bypass surgery, ejection fraction increased from 37.8±9.0% to 45.5±12.3% in 22 patients who had decreased ejectin fraction preoperatively. Wall motion improved in 103 (72.5%) segments among 142 dysfunctional segments. Positive predictive values (PPV) of Rev, Rest, Del, and Thk were 83%, 76%, 43%, and 69% respectively. Negative predictive values (NPV) of Rev, Rest, Del, and Thk were 48%, 44%, 58%, and 21%, respectively. Rest/gated stress/delay SPECT had PPV of 74% and NPV of 46%. Through univariate logistic regression analysis revealed Rev( p=0.0008) and Rest (p=0.024) as significant predictors, stepwise multivariate test found Rev as the only good predictor (p=0.0008). Among independent predictors obtained by rest Tl-201/stress gated Tc-99m-MIBI/delayed Tl-201 myocardial SPECT for wall motion improvement after bypass surgery, stress-rest reversibility was the single most useful predictor

  10. An experimental study on compressive behavior of rubble stone walls retrofitted with BFRP grids

    Science.gov (United States)

    Huang, Hui; Jia, Bin; Li, Wenjing; Liu, Xiao; Yang, Dan; Deng, Chuanli

    2018-03-01

    An experimental study was conducted to investigate the compressive behavior of rubble stone walls retrofitted with BFRP grids. The experimental program consisted of four rubble stone walls: one unretrofitted rubble stone wall (reference wall) and three BFRP grids retrofitted rubble stone walls. The main purpose of the tests was to gain a better understanding of the compressive behavior of rubble stone walls retrofitted with different amount of BFRP grids. The experimental results showed that the reference wall failed with out-of-plane collapse due to poor connection between rubble stone blocks and the three BFRP grids retrofitted walls failed with BFRP grids rupture followed by out-of-plane collapse. The measured compressive strength of the BFRP grids retrofitted walls is about 1.4 to 2.5 times of that of the reference wall. Besides, the rubble stone wall retrofitted with the maximum amount of BFRP grids showed the minimum vertical and out-of-plane displacements under the same load.

  11. Myocardial imaging in acute myocardial infarction using. beta. -methyl-p-( sup 123 I)-iodophenylpentadecanoic acid; Comparison with sup 201 Tl imaging and wall motion

    Energy Technology Data Exchange (ETDEWEB)

    Naruse, Hitoshi; Itano, Midoriko; Kondo, Tomohiro (Hyogo College of Medicine, Nishinomiya (Japan)) (and others)

    1992-01-01

    Myocardial imaging using {beta}-methyl-p-({sup 123}I)-iodophenylpentadecanoic acid (BMIPP) was performed in 11 patients with acute myocardial infarction. The left ventricular images were divided into 12 segments, and myocardial images with BMIPP were compared with coronary angiography (CAG), thallium-201 myocardial scintigraphy (Tl) and wall motion obtained by two-dimensional echocardiography (WM). When the culprit lesion was at the proximal point of the left anterior descending artery (LAD), all segments showed depressed uptake. In 3 cases with single vessel disease of the LAD, inferior wall of the basis showed reduced uptake of BMIPP despite the location of the culprit lesion. In cases with discordant uptake between the two tracers, BMIPP frequently showed more severely depressed uptake than Tl in the subacute phase, although the uptake of BMIPP correlated with that of Tl ({tau}=0.82, p<0.001). In such cases, the discordance was related to the improvement in WM from the acute phase to the convalescent phase. BMIPP uptake correlated with WM in the subacute phase ({tau}=0.50, p<0.001). BMIPP showed more severely depressed uptake while WM showed mild asynergy in most cases in which discordance was found between the BMIPP and WM findings. However, there was no correlation between the change in WM from the acute to subacute phases, or the uptakes of BMIPP and Tl alone. We concluded that the myocardial condition can be evaluated in detail in acute myocardial infarction by comparing the findings of BMIPP with those of Tl and WM. (author).

  12. [Myocardial imaging in acute myocardial infarction using beta-methyl-p-(123I)-iodophenylpentadecanoic acid: comparison with 201Tl imaging and wall motion].

    Science.gov (United States)

    Naruse, H; Itano, M; Kondo, T; Kogame, T; Yamamoto, J; Morita, M; Kawamoto, H; Fukutake, N; Ohyanagi, M; Iwasaki, T

    1992-01-01

    Myocardial imaging using beta-methyl-p-(123I)-iodophenylpentadecanoic acid (BMIPP) was performed in 11 patients with acute myocardial infarction. The left ventricular images were divided into 12 segments, and myocardial imagings with BMIPP were compared with coronary angiography (CAG), thallium-201 myocardial scintigraphy (TL) and wall motion obtained by two-dimensional echocardiography (WM). When the culprit lesion was at the proximal point of the left anterior descending artery (LAD), all segments showed depressed uptake. In 3 cases with single vessel disease of the LAD, inferior wall of the basis showed reduced uptake of BMIPP despite the location of the culprit lesion. In cases with discordant uptake between the two tracers, BMIPP frequently showed more severely depressed uptake than TL in the subacute phase, although the uptake of BMIPP correlated with that of TL (tau = 0.82, p less than 0.001). In such cases, the discordance was related to the improvement in WM from the acute phase to the convalescent phase. BMIPP uptake correlated with WM in the subacute phase (tau = 0.50, p less than 0.001). BMIPP showed more severely depressed uptake while WM showed mild asynergy in most cases in which discordance was found between the BMIPP and WM findings. However, there was no correlation between the change in WM from the acute to subacute phases, or the uptakes of BMIPP and TL alone. We concluded that the myocardial condition can be evaluated in detail in acute myocardial infarction by comparing the findings of BMIPP with those of TL and WM.

  13. Study of the motion and deposition of micro particles in a vertical tube containing uniform gas flow

    Science.gov (United States)

    Abolpour, Bahador; Afsahi, M. Mehdi; Soltani Goharrizi, Ataallah; Azizkarimi, Mehdi

    2017-12-01

    In this study, effects of a gaseous jet, formed in a vertical tube containing a uniform gas flow, on the injected micro particles have been investigated. A CFD model has been developed to simulate the particle motion in the tube. This simulation is very close to the experimental data. The results show that, increasing the flow rate of carrier gas or decreasing the flow rate of surrounding gas increases the effect of gaseous jet and also increases trapping rate of the particles by the tube wall. The minimum and maximum residence times of particles approach together with increasing the size of solid particles. Particles larger than 60 μm have a certain and fixed residence time at different flow rates of the carrier or surrounding gas. About 40 μm particle size has minimal trapping by the tube wall at various experimental conditions.

  14. Ground motion studies in a backfilled stope at West Driefontein

    CSIR Research Space (South Africa)

    Goldbach, OD

    1991-10-01

    Full Text Available This report looks at the ground motion from 24 small magnitude seismic events recorded at various points inside a backfilled stope. The in-stope ground motion is compared to that recorded at an off-reef site. The seismic events are analysed...

  15. A SOFTWARE TOOL FOR EXPERIMENTAL STUDY LEAP MOTION

    OpenAIRE

    Georgi Krastev; Magdalena Andreeva

    2015-01-01

    The paper aims to present computer application that illustrates Leap Motion controller’s abilities. It is a peripheral and software for PC, which enables control by natural user interface based on gestures. The publication also describes how the controller works and its main advantages/disadvantages. Some apps using leap motion controller are discussed.

  16. Application of laser resonance scattering to the study of high-temperature plasma-wall interaction

    International Nuclear Information System (INIS)

    Maeda, Mitsuo; Muraoka, Katsunori; Hamamoto, Makoto; Akazaki, Masanori; Miyazoe, Yasushi

    1981-01-01

    Studies on laser resonance scattering and its application to the study of high-temperature plasma-wall interaction are reviewed. The application of dye laser beam to resonant scattering method has been developed. This method is able to detect low density atoms. The fluorescent photon counts can be estimated for a two-level system and a three-level system. The S/N ratio, Which is in close connection with the detection limit, has been estimated. The doppler effect due to the thermal motion of atoms is taken into consideration. The calibration of the absolute number of atoms is necessary. Tunable coherent light is used as the light source for resonance scattering method. This is able to excite atoms strongly and to increase the detection efficiency. As dye lasers, a N 2 laser, a YAG laser, and a KrF excimer laser have been studied. In VUV region, rare gas or rare gas halide lasers can be used. The strong output power can be expected when the resonance lines of atoms meet the synchronizing region of the excimer laser. The resonance scattering method is applied to the detection of impurity metal atoms in plasma. The studies of laser systems for the detection of hydrogen atoms are also in progress. (Kato, T.)

  17. Gas leakage rate through reinforced concrete shear walls: Numerical study

    International Nuclear Information System (INIS)

    Wang Ting; Hutchinson, Tara C.

    2005-01-01

    Unlined reinforced concrete shear walls are often used as 'tertiary boundaries' in the United States Department of Energy (DOE) to house dangerous gases. An unanticipated event, such as an earthquake, may cause gases stored inside the walls to disperse into the environment resulting in excess pollution. To address this concern, in this paper, a methodology to numerically predict the gas leakage rate through these shear walls under lateral loading conditions is proposed. This methodology involves finite element and flow rate analysis. Strain distributions are obtained from the finite element analysis, and then used to simulate the crack characteristics on the concrete specimen. The flow rate through the damaged concrete specimen is then estimated using flow rate formulas available from the literature. Results from an experimental specimen are used to evaluate the methodology, and particularly its robustness in the flow rate estimation

  18. Implied motion because of instability in Hokusai Manga activates the human motion-sensitive extrastriate visual cortex: an fMRI study of the impact of visual art.

    Science.gov (United States)

    Osaka, Naoyuki; Matsuyoshi, Daisuke; Ikeda, Takashi; Osaka, Mariko

    2010-03-10

    The recent development of cognitive neuroscience has invited inference about the neurosensory events underlying the experience of visual arts involving implied motion. We report functional magnetic resonance imaging study demonstrating activation of the human extrastriate motion-sensitive cortex by static images showing implied motion because of instability. We used static line-drawing cartoons of humans by Hokusai Katsushika (called 'Hokusai Manga'), an outstanding Japanese cartoonist as well as famous Ukiyoe artist. We found 'Hokusai Manga' with implied motion by depicting human bodies that are engaged in challenging tonic posture significantly activated the motion-sensitive visual cortex including MT+ in the human extrastriate cortex, while an illustration that does not imply motion, for either humans or objects, did not activate these areas under the same tasks. We conclude that motion-sensitive extrastriate cortex would be a critical region for perception of implied motion in instability.

  19. Studying energy absorption in tapered thick walled tubes

    Directory of Open Access Journals (Sweden)

    P. Hosseini Tehrani

    Full Text Available In many engineering structures different energy absorption systems may be used to improve crashworthiness capability of the system and to control damages that may occur in a system during an accident. Therefore, extensive research has been done on the energy-absorbing cells. In this paper, energy absorption in tapered thick walled tubes has been investigated. As a practical case, studies have been focused on the crush element of Siemens ER24PC locomotive. To investigate performance of this part at collision time, it has been modeled in Abaqus software and its collision characteristics have been evaluated. Considering that the crash element is folded at time of collision, an analytical approach has been presented for calculation of instantaneous folding force under axial load. Basis of this method is definition and analysis of main folding mechanism and calculation of average folding force. This method has been used for validation of the results of numerical solution. Since sheet thickness of the crash element is high and may be ruptured at time of collision, some damage models have been used for numerical simulations. One of the three damage models used in this paper is available in the software and coding has been done for two other damage models and desirable damage model has been specified by comparing results of numerical solution with results of laboratory test. In addition, authenticity of the desirable damage model has been studied through ECE R 66 standard. To improve crashworthiness characteristic some attempts, such as use of metal foam and creation of trigger in suitable situations to reduce maximum force resulting from collision, have been performed. Finally though different simulation optimal crush element has been introduced and its performance and efficiency have been evaluated.

  20. The value of regional wall motion abnormalities on gated mycardiac perfusion imaging in perfusion imaging in predicting angiographic stenoses of coronary artery

    International Nuclear Information System (INIS)

    Yao Lixin; Liu Binbin

    2007-01-01

    Objective: To determine the possible level of angiographic stenoses of coronary artery at which reversible regional wall motion abnormalities (RWMA) are present on 99m Tc-sestamibi ( 99m Tc-MIBI)-gated myocardial perfusion imaging (MPI). Methods: ninty patients undergoing coronary angiography MPI within two weeks were recruited. A five grades and nine segments marking system was introduced to assess the RWMA and thickening of left ventricles. Results: The sensitivity of reversible RWMA for detecting ≥75% angiographic stenoses was 64%,with a specificity of 95% and positive predictive value of 97%. The presence of reversible RWMA was able to stratify patients with severe angiographic stenoses of 75% or more from those less than 75% with high positive predictive value. A good correlation was noted between the presence of reversible RWMA and the coronary artery jeopardy score. Multivariate analysis showed that the post-stress RWMA and reversible RWMA scores and positive dipyridamole-stress exercise electrocardiogram(ECG) were significant predictors of angiographic severity. Conclusions: Reversible RWMA, as shown by dipyridamole stress 99m Tc-MIBI MPI, is a significant predictor of angiographic disease with very high specificity and adds incremental value to MPI for the assessment of angiographic severity. (authors)

  1. Numerical Study of Motion of Falling Conical Graupel

    Science.gov (United States)

    Chueh, Chih-Che; Wang, Pao K.; Hashino, Tempei

    2018-01-01

    In the present study, the attitudes of freely-falling conical graupel with a realistic range of densities are investigated numerically by solving the transient Navier-Stokes equations and the body dynamics equations representing the 6-degrees-of-freedom motion. This framework allows us to determine the position and orientation of the graupel in response to the hydrodynamic force of the flow fields. The results show more significant horizontal movements than those cases with a fixed bulk density of ice assumed in our previous study. This is because the real graupel particles possess the density less than the bulk density of ice, which, in turn, leads to a relatively small mass and a relatively small set of moments of inertia. We demonstrate that, with the six degrees of freedom considered together, when Reynolds number is small, a typical damped oscillation occurs, whereas when Reynolds number is high, amplifying oscillation may occur which leads to more complicated and unpredictable flying attitudes such as tumbling. The drag coefficients obtained in the present study agree with the previous studies and can be approximated by that of spheres of the same Reynolds numbers. We also show that conical graupel can perform significant horizontal translations which can be on the order of 1 km in 1 h.

  2. Histological and ultrastructural study of the gastric wall of the ...

    African Journals Online (AJOL)

    1989-01-05

    Jan 5, 1989 ... The stomach wall of the freshwater bream 0. mossambicus is described and compared with that of other bony fishes and vertebrates. The histology of the stomach layers and fine structure of the various cell types of. 0. mossambicus are basically similar to the correspondlngcells of other vertebrates although ...

  3. Histopathological and immunohistochemical study of the wall of ...

    African Journals Online (AJOL)

    Introduction: Varicocele is defined as a pathological alteration in the venous circulation of the testis which appears almost exclusively on the left side. The aim of current work was to compare the normal structure of the wall of the veins of the pampiniform plexus and also to highlight the occurrence of any structural alterations ...

  4. A Study on the Bio-mimetic Motion of Reptiles

    International Nuclear Information System (INIS)

    Shin, Hochelo; Kim, Changhoi; Eom, Heungseop; Jeong, Kyungmin; Jung, Seungjo

    2013-10-01

    After investigating the locomotion based on the biological characteristics about the from a literature search about the reptile, the locomotion of lizards is captured with marker based motion capture system. Tested lizards are Cuban anole, bearded dragon, domestic lizards such as a white-striped grass lizard and a leopard lizard, After analyzing the motion of the lizards with the measured data, a 25 DOF kinematics model of a lizard was proposed. A periodic gait of the lizard was modeled by defining gait parameters. The body structure of the lizard was analyzed with a bone specimen for the kinematics modeling. Dynamics parameters such as a mass and a inertia of a link are obtained by measuring the weight and the volume of each link. The crawl and the trot gait were simulated with the dynamics model. To control the poly-morphic motion of snake robot, various locomotions of snakes and the motion algorithm of snake robots were investigated. A test model of snake robot and a control system were developed to analyzed the motion and energy efficiency according to the gaits and to realize the poly-morphic motion control

  5. A Study on the Bio-mimetic Motion of Reptiles

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hochelo; Kim, Changhoi; Eom, Heungseop; Jeong, Kyungmin; Jung, Seungjo

    2013-10-15

    After investigating the locomotion based on the biological characteristics about the from a literature search about the reptile, the locomotion of lizards is captured with marker based motion capture system. Tested lizards are Cuban anole, bearded dragon, domestic lizards such as a white-striped grass lizard and a leopard lizard, After analyzing the motion of the lizards with the measured data, a 25 DOF kinematics model of a lizard was proposed. A periodic gait of the lizard was modeled by defining gait parameters. The body structure of the lizard was analyzed with a bone specimen for the kinematics modeling. Dynamics parameters such as a mass and a inertia of a link are obtained by measuring the weight and the volume of each link. The crawl and the trot gait were simulated with the dynamics model. To control the poly-morphic motion of snake robot, various locomotions of snakes and the motion algorithm of snake robots were investigated. A test model of snake robot and a control system were developed to analyzed the motion and energy efficiency according to the gaits and to realize the poly-morphic motion control.

  6. Molecular Dynamics Study of Thermally Augmented Nanodroplet Motion on Chemical Energy Induced Wettability Gradient Surfaces.

    Science.gov (United States)

    Chakraborty, Monojit; Chowdhury, Anamika; Bhusan, Richa; DasGupta, Sunando

    2015-10-20

    Droplet motion on a surface with chemical energy induced wettability gradient has been simulated using molecular dynamics (MD) simulation to highlight the underlying physics of molecular movement near the solid-liquid interface including the contact line friction. The simulations mimic experiments in a comprehensive manner wherein microsized droplets are propelled by the surface wettability gradient against forces opposed to motion. The liquid-wall Lennard-Jones interaction parameter and the substrate temperature are varied to explore their effects on the three-phase contact line friction coefficient. The contact line friction is observed to be a strong function of temperature at atomistic scales, confirming their experimentally observed inverse functionality. Additionally, the MD simulation results are successfully compared with those from an analytical model for self-propelled droplet motion on gradient surfaces.

  7. Proposal for an All-Spin Artificial Neural Network: Emulating Neural and Synaptic Functionalities Through Domain Wall Motion in Ferromagnets.

    Science.gov (United States)

    Sengupta, Abhronil; Shim, Yong; Roy, Kaushik

    2016-12-01

    Non-Boolean computing based on emerging post-CMOS technologies can potentially pave the way for low-power neural computing platforms. However, existing work on such emerging neuromorphic architectures have either focused on solely mimicking the neuron, or the synapse functionality. While memristive devices have been proposed to emulate biological synapses, spintronic devices have proved to be efficient at performing the thresholding operation of the neuron at ultra-low currents. In this work, we propose an All-Spin Artificial Neural Network where a single spintronic device acts as the basic building block of the system. The device offers a direct mapping to synapse and neuron functionalities in the brain while inter-layer network communication is accomplished via CMOS transistors. To the best of our knowledge, this is the first demonstration of a neural architecture where a single nanoelectronic device is able to mimic both neurons and synapses. The ultra-low voltage operation of low resistance magneto-metallic neurons enables the low-voltage operation of the array of spintronic synapses, thereby leading to ultra-low power neural architectures. Device-level simulations, calibrated to experimental results, was used to drive the circuit and system level simulations of the neural network for a standard pattern recognition problem. Simulation studies indicate energy savings by  ∼  100× in comparison to a corresponding digital/analog CMOS neuron implementation.

  8. Study of stream flow effects on bubble motion

    International Nuclear Information System (INIS)

    Sami, S.S.

    1983-01-01

    The formation of air bubbles at constant-pressure by submerged orifices was investigated in both quiescent and moving streams inside a vertical tube. Parameters affecting the bubble rise velocity, such as bubble generating frequency and diameter, were studied and analyzed for bubbles rising in a chain and homogeneous mixture. A special technique for measuring bubble motion parameters has been developed, tested, and employed throughout the experimental investigation. The method is based on a water-air impedance variation. Results obtained in stagnant liquid show that increasing the bubble diameter serves to increase bubble rise velocity, while an opposite trend has been observed for stream liquid where the bubble diameter increase reduces the bubble rise velocity. The increase of bubble generation frequency generally increases the bubble rise velocity. Experimental data covered with bubble radial distribution showed symmetrical profiles of bubble velocity and frequency, and the radial distribution of the velocity profiles sometimes has two maxima and one minimum depending on the liquid velocity. Finally, in stagnant liquid, a normalized correlation has been developed to predict the terminal rise velocity in terms of bubble generating frequency, bubble diameter, single bubble rise velocity, and conduit dimensions. Another correlation is presented for forced bubbly flow, where the bubble rise velocity is expressed as a function of bubble generating frequency, bubble diameter, and water superficial velocity

  9. Time and Motion Study of a Community Patient Navigator

    Directory of Open Access Journals (Sweden)

    Sara S. Phillips

    2014-04-01

    Full Text Available Research on patient navigation has focused on validating the utility of navigators by defining their roles and analyzing their effects on patient outcomes, patient satisfaction, and cost effectiveness. Patient navigators are increasingly used outside the research context, and their roles without research responsibilities may look very different. This pilot study captured the activities of a community patient navigator for uninsured women with a positive screening test for breast cancer, using a time and motion approach over a period of three days. We followed the actions of this navigator minute by minute to assess the relative ratios of actions performed and to identify areas for time efficiency improvement to increase direct time with patients. This novel approach depicts the duties of a community patient navigator no longer fettered by navigation logs, research team meetings, surveys, and the consent process. We found that the community patient navigator was able to spend more time with patients in the clinical context relative to performing paperwork or logging communication with patients as a result of her lack of research responsibilities. By illuminating how community patient navigation functions as separate from the research setting, our results will inform future hiring and training of community patient navigators, system design and operations for improving the efficiency and efficacy of navigators, and our understanding of what community patient navigators do in the absence of research responsibilities.

  10. A numerical study of external building walls containing phase change materials (PCM)

    International Nuclear Information System (INIS)

    Izquierdo-Barrientos, M.A.; Belmonte, J.F.; Rodríguez-Sánchez, D.; Molina, A.E.; Almendros-Ibáñez, J.A.

    2012-01-01

    Phase Change Materials (PCMs) have been receiving increased attention, due to their capacity to store large amounts of thermal energy in narrow temperature ranges. This property makes them ideal for passive heat storage in the envelopes of buildings. To study the influence of PCMs in external building walls, a one-dimensional transient heat transfer model has been developed and solved numerically using a finite difference technique. Different external building wall configurations were analyzed for a typical building wall by varying the location of the PCM layer, the orientation of the wall, the ambient conditions and the phase transition temperature of the PCM. The integration of a PCM layer into a building wall diminished the amplitude of the instantaneous heat flux through the wall when the melting temperature of the PCM was properly selected according to the season and wall orientation. Conversely, the results of the work show that there is no significant reduction in the total heat lost during winter regardless of the wall orientation or PCM transition temperature. Higher differences were observed in the heat gained during the summer period, due to the elevated solar radiation fluxes. The high thermal inertia of the wall implies that the inclusion of a PCM layer increases the thermal load during the day while decreasing the thermal load during the night. - Highlights: ► A comparative simulation of a building wall with and without PCMs has been conducted. ► PCM is selected according with the season, the wall orientation and the melting temperature. ► PCM in a building wall help to diminish the internal air temperature swings and to regulate the heat transfer.

  11. Methods for determining the wall thickness variation of tubular heaters used in thermalhydraulic studies

    International Nuclear Information System (INIS)

    Cubizolles, G.; Garnier, J.; Groeneveld, D.; Tanase, A.

    2009-01-01

    Fuel bundle simulators used in thermalhydraulic studies typically consist of bundles of directly heated tubes. It is usually assumed that the heater tubes have a uniform circumferential heat flux distribution. In practice, this heat flux distribution is never exactly uniform because of wall thickness variations and bore eccentricity. Ignoring the non-uniformity in wall thickness can lead to under-estimating the local heat transfer coefficients. During nucleate boiling tests in a 5x5 PWR-type bundle subassembly at CEA-Grenoble, a sinusoidal temperature distribution was observed around the inside circumference of the heater rods. These heater rods were equipped with high-accuracy sliding thermocouple probes that permit the detailed measurement of the internal wall temperature distribution, both axially and circumferentially. The sinusoidal temperature distribution strongly suggests a variation in wall thickness. A methodology was subsequently derived to determine the circumferential wall thickness variation. The method is based on the principle that for directly heated fuel-element simulators, the nucleate boiling wall superheat at high pressures is nearly uniform around the heater rod circumference. The results show wall thickness variations of up to ±4% which was confirmed by subsequent ultrasonic wall-thickness measurements performed after bundle disassembly. Non-uniformities in circumferential temperature distributions were also observed during parallel thermalhydraulic tests at the University of Ottawa (UofO) on an electrically heated tube cooled internally by R-134a and equipped with fixed thermocouples on the outside. From the measured wall temperatures and knowledge of the inside heat transfer coefficient or wall temperature distribution, the variations in wall thickness and surface heat flux to the coolant were evaluated by solving conduction equations using three separate sets of data (1) single phase heat transfer data, (2) nucleate boiling data, and (3

  12. Study on Seismic Behavior of Recycled Concrete Energy-efficient Homes Structure Wall

    Directory of Open Access Journals (Sweden)

    Dong Lan

    2016-01-01

    Full Text Available The main point is to study the seismic behavior of the lattice type recycled concrete energy saving wall under low-cyclic loading,to provide the basis for the seismic performance of application of recycled concrete lattice wall in energy-saving residential structure. Design two walls with the same structure measures, include Lattice type recycled concrete wall and natural concrete wall, they are tested under low-cycle repetitive loading, compared failure mode and seismic performance in different reinforcement conditions of side column. The bearing capacity and ductility of recycled aggregate concrete are better than natural aggregate concrete, The stiffness degradation curves and the skeleton curves of the walls are basically the same, both of them have better seismic energy dissipation capacity. Lattice type concrete wall is good at seismic performance, recycled aggregate concrete is good at plastic deformation ability, it is advantageous to seismic energy dissipation of wall, it can be applied in energy efficient residential structure wall.

  13. Could quantitative longitudinal peak systolic strain help in the detection of left ventricular wall motion abnormalities in our daily echocardiographic practice?

    Science.gov (United States)

    Benyounes, Nadia; Lang, Sylvie; Gout, Olivier; Ancédy, Yann; Etienney, Arnaud; Cohen, Ariel

    2016-10-01

    Transthoracic echocardiography is the most commonly used tool for the detection of left ventricular wall motion (LVWM) abnormalities using "naked eye evaluation". This subjective and operator-dependent technique requires a high level of clinical training and experience. Two-dimensional speckle-tracking echocardiography (2D-STE), which is less operator-dependent, has been proposed for this purpose. However, the role of on-line segmental longitudinal peak systolic strain (LPSS) values in the prediction of LVWM has not been fully evaluated. To test segmental LPSS for predicting LVWM abnormalities in routine echocardiography laboratory practice. LVWM was evaluated by an experienced cardiologist, during routine practice, in 620 patients; segmental LPSS values were then calculated. In this work, reflecting real life, 99.6% of segments were successfully tracked. Mean (95% confidence interval [CI]) segmental LPSS values for normal basal (n=3409), mid (n=3468) and apical (n=3466) segments were -16.7% (-16.9% to -16.5%), -18.2% (-18.3% to -18.0%) and -21.1% (-21.3% to -20.9%), respectively. Mean (95% CI) segmental LPSS values for hypokinetic basal (n=114), mid (n=116) and apical (n=90) segments were -7.7% (-9.0% to -6.3%), -10.1% (-11.1% to -9.0%) and -9.3% (-10.5% to -8.1%), respectively. Mean (95% CI) segmental LPSS values for akinetic basal (n=128), mid (n=95) and apical (n=91) segments were -6.6% (-8.0% to -5.1%), -6.1% (-7.7% to -4.6%) and -4.2% (-5.4% to -3.0%), respectively. LPSS allowed the differentiation between normal and abnormal segments at basal, mid and apical levels. An LPSS value≥-12% detected abnormal segmental motion with a sensitivity of 78% for basal, 70% for mid and 82% for apical segments. Segmental LPSS values may help to differentiate between normal and abnormal left ventricular segments. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. Study on the Microwave Permittivity of Single-Walled Carbon Nanotube

    Science.gov (United States)

    Liu, Xiaolai; Zhao, Donglin

    2009-01-01

    In this article, we studied the microwave permittivity of the complex of the single-walled carbon nanotube and paraffin in 2-18GHz. In the range, the dielectric loss of single-walled carbon nanotube is higher, and the real part and the imaginary part of the dielectric constant decrease with the increase of frequency, and the dielectric constant…

  15. Experimental and numerical study of heat transfer across insulation wall of a refrigerated integral panel van

    International Nuclear Information System (INIS)

    Glouannec, Patrick; Michel, Benoit; Delamarre, Guillaume; Grohens, Yves

    2014-01-01

    This paper presents an experimental and numerical design study of an insulation wall for refrigerated vans. The thermophysical properties of the insulating multilayer panel, the external environment impact (solar irradiation, temperature, etc.) and durability are taken into account. Different tools are used to characterize the thermal performances of the insulation walls and the thermal properties of the insulation materials are measured. In addition, an experiment at the wall scale is carried out and a 2D FEM model of heat and mass transfer within the wall is formulated. Three configurations are studied with this design approach. Multilayer insulation walls containing reflective multi-foil insulation, aerogel and phase change materials (PCM) are tested. Promising results are obtained with these materials, especially the reduction of peak heat transfer and energy consumption during the daytime period. Furthermore, the major influence of solar irradiation is highlighted as it can increase the peak heat transfer crossing the insulation wall by up to 43%. Nevertheless, we showed that the use of reflective multi-foil insulation and aerogel layers allowed decreasing this impact by 27%. - Highlights: • A design study of an insulation wall for a refrigerated van is carried out. • Experimental and numerical studies of multilayer insulation walls are performed. • The major influence of solar irradiation is highlighted. • New insulation materials (reflective multi-foil, aerogel and PCM) are tested

  16. Neural mechanisms underlying sound-induced visual motion perception: An fMRI study.

    Science.gov (United States)

    Hidaka, Souta; Higuchi, Satomi; Teramoto, Wataru; Sugita, Yoichi

    2017-07-01

    Studies of crossmodal interactions in motion perception have reported activation in several brain areas, including those related to motion processing and/or sensory association, in response to multimodal (e.g., visual and auditory) stimuli that were both in motion. Recent studies have demonstrated that sounds can trigger illusory visual apparent motion to static visual stimuli (sound-induced visual motion: SIVM): A visual stimulus blinking at a fixed location is perceived to be moving laterally when an alternating left-right sound is also present. Here, we investigated brain activity related to the perception of SIVM using a 7T functional magnetic resonance imaging technique. Specifically, we focused on the patterns of neural activities in SIVM and visually induced visual apparent motion (VIVM). We observed shared activations in the middle occipital area (V5/hMT), which is thought to be involved in visual motion processing, for SIVM and VIVM. Moreover, as compared to VIVM, SIVM resulted in greater activation in the superior temporal area and dominant functional connectivity between the V5/hMT area and the areas related to auditory and crossmodal motion processing. These findings indicate that similar but partially different neural mechanisms could be involved in auditory-induced and visually-induced motion perception, and neural signals in auditory, visual, and, crossmodal motion processing areas closely and directly interact in the perception of SIVM. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Moving beyond the Wall(s): Theorizing Corporate Identity for Global Cultural Studies

    Science.gov (United States)

    Elavsky, C. Michael

    2009-01-01

    This article examines the set of research considerations that went into investigating the relationship between the Bertelsmann Music Group (BMG) and Czech music culture as a means of exploring alternative avenues and frameworks for understanding and doing global cultural studies. Outlining the theoretical and methodological trajectories, as well…

  18. 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.

  19. A study of UGI series for improvement of diagnosis on the anterior wall of the stomach

    International Nuclear Information System (INIS)

    Lee, Won Hong; Son, Soon Yong; Kang, Hyoung Wook

    1997-01-01

    This paper is to investigate a more detailed method for the diagnosis of anterior wall of the stomach by making a comparative study with several hospitals. It has been true that there have been hospitals, that have not examined anterior wall of the stomach. However, it is very important for us to examine anterior wall of the stomach for an early detection of gastric carcinoma. The results of the study are as follows : 1. Frequency of occurrence of the early gastric carcinoma for the anterior wall were 50 cases and 34 cases for the posterior wall out of 84 cases. 2. Only a hospitals have examined the anterior wall of stomach. 3. In case of operation, only a hospitals have used two techniques at for same time single and double contrast studies. 4. Only one hospital used a compression pad and three hospitals had only filing state images taken. 5. In general, l chest of film was used and the number of exposures rouged from 1 to 2 times. Lesions on the anterior wall of the stomach can be shown by the combination of prone single compression and supine double contrast radiographs. Therefore, the conclusion came to the result that the prone single compression and supine double contract technique of the anterior wall are indispensable methods to the routine check of the stomach

  20. Simultaneous measurement of instantaneous heart rate and chest wall plethysmography in short-term, metronome guided heart rate variability studies: suitability for assessment of autonomic dysfunction.

    Science.gov (United States)

    Perring, S; Jones, E

    2003-08-01

    Instantaneous heart rate and chest wall motion were measured using a 3-lead ECG and an air pressure chest wall plethysmography system. Chest wall plethysmography traces were found to accurately represent the breathing pattern as measured by spirometry (average correlation coefficient 0.944); though no attempt was made to calibrate plethysmography voltage output to tidal volume. Simultaneous measurements of heart rate and chest wall motion were made for short periods under metronome guided breathing at 6 breaths per minute. The average peak to trough heart rate change per breath cycle (AVEMAX) and maximum correlation between heart rate and breathing cycle (HRBRCORR) were measured. Studies of 44 normal volunteers indicated clear inverse correlation of heart rate variability parameters with age (AVEMAX R = -0.502, P < 0.001) but no significant change in HRBRCORR with age (R = -0.115). Comparison of normal volunteers with diabetics with no history of symptoms associated with autonomic failure indicated significant lower heart rate variability in diabetics (P = 0.005 for AVEMAX) and significantly worse correlation between heart rate and breathing (P < 0.001 for HRBRCORR). Simultaneous measurement of heart rate and breathing offers the possibility of more sensitive diagnosis of autonomic failure in a simple bedside test and gives further insight into the nature of cardio-ventilatory coupling.

  1. Avaliação quantitativa da movimentação parietal regional do ventrículo esquerdo na endomiocardiofibrose Quantitative assessment of left ventricular regional wall motion in endomyocardial fibrosis

    Directory of Open Access Journals (Sweden)

    Charles Mady

    2005-03-01

    motion in patients with endomyocardial fibrosis (EMF. METHODS: The study comprised 88 patients, 59 of the female sex, with a mean age of 39±13 years (range, 9 to 65 and with echocardiographic and angiographic evidence of left ventricular EMF. The intensity of fibrous tissue buildup on contrast cineventriculography was classified as mild, moderate, or severe. The overall left ventricular ejection fraction (LVEF was determined by using the area-length method on ventriculography. The motion was measured in 100 equidistant chords perpendicular to the centerline drawn in the middle of the final diastolic and systolic contours and normalized to cardiac size. Five left ventricular segments were analyzed: A - apical; AL - anterolateral; AB - anterobasal; IA - inferoapical; IB - inferobasal. Abnormality was expressed in units of standard deviation of the mean motion in a normal population of reference, comprised of 103 patients with normal LV according to clinical and electrocardiographic data, and angiographic standards. RESULTS: Mean LVEF was 0.47±0.12. Fibrous tissue buildup in the left ventricle was mild in 12 patients, moderate in 40, and severe in 36. The regions with the poorest ventricular wall motion were A (-1.4±1.6 standard deviation/chords and IA (-1.6±1.8 standard deviation/chords compared with that in AB (-0.3±1.9 standard deviation/chords, AL (-0.5±1.8 standard deviation/chords and IB (-0.9±1.3 standard deviation/chords. No relation was observed between the intensity of fibrous tissue buildup and regional ventricular wall motion. CONCLUSION: A change in LV regional wall motion exists in EMF, and it is independent of the intensity of fibrous tissue buildup qualitatively assessed. Nonuniform involvement of the LV should be considered when planning surgery for this disease.

  2. Experimental and theoretical study on natural circulation capacity under rolling motion condition

    International Nuclear Information System (INIS)

    Tan Sichao; Gao Puzhen

    2007-01-01

    Effect of rolling motion on natural circulation capacity was studied experimentally and theoretically. Experiments were conducted under the conditions of rolling and unrolling motions. The experimental results show that natural circulation capacity decreases under rolling motion condition. A mathematic model was developed to calculate the natural circulation capacity under rolling motion condition, considering the characteristics of natural circulation, the model was modified. The calculated results agree with experimental data well. Effect of rolling motion on natural circulation was analyzed through calculation and the following conclusions were obtained: (1) The increase of flow resistance coefficient is the main reason that the natural circulation capacity decreases under rolling motion condition; (2) Non-uniform distribution of fluid mass in the pipe has also influence on natural circulation capacity. (author)

  3. Study of radial die-wall pressure changes during pharmaceutical powder compaction.

    Science.gov (United States)

    Abdel-Hamid, Sameh; Betz, Gabriele

    2011-04-01

    In tablet manufacturing, less attention is paid to the measurement of die-wall pressure than to force-displacement diagrams. Therefore, the aim of this study was to investigate radial stress change during pharmaceutical compaction. The Presster(TM), a tablet-press replicator, was used to characterize compaction behavior of microcrystalline cellulose (viscoelastic), calcium hydrogen phosphate dihydrate (brittle), direct compressible mannitol (plastic), pre-gelatinized starch (plastic/elastic), and spray dried lactose monohydrate (plastic/brittle) by measuring radial die-wall pressure; therefore powders were compacted at different (pre) compaction pressures as well as different speeds. Residual die-wall pressure (RDP) and maximum die-wall pressure (MDP) were measured. Various tablet physical properties were correlated to radial die-wall pressure. With increasing compaction pressure, RDP and MDP (P compaction behavior of materials and detecting friction phenomena in the early stage of development.

  4. Active and passive kink mode studies in a tokamak with a movable ferromagnetic wall

    Energy Technology Data Exchange (ETDEWEB)

    Levesque, J. P.; Hughes, P. E.; Bialek, J.; Byrne, P. J.; Mauel, M. E.; Navratil, G. A.; Peng, Q.; Rhodes, D. J.; Stoafer, C. C. [Department of Applied Physics and Applied Mathematics, Columbia University, 500 W. 120th Street, New York, New York 10027 (United States)

    2015-05-15

    High-resolution active and passive kink mode studies are conducted in a tokamak with an adjustable ferromagnetic wall near the plasma surface. Ferritic tiles made from 5.6 mm thick Hiperco{sup ®} 50 alloy have been mounted on the plasma-facing side of half of the in-vessel movable wall segments in the High Beta Tokamak-Extended Pulse device [D. A. Maurer et al., Plasma Phys. Controlled Fusion 53, 074016 (2011)] in order to explore ferritic resistive wall mode stability. Low-activation ferritic steels are a candidate for structural components of a fusion reactor, and these experiments examine MHD stability of plasmas with nearby ferromagnetic material. Plasma-wall separation for alternating ferritic and non-ferritic wall segments is adjusted between discharges without opening the vacuum vessel. Amplification of applied resonant magnetic perturbations and plasma disruptivity are observed to increase when the ferromagnetic wall is close to plasma surface instead of the standard stainless steel wall. Rapidly rotating m/n=3/1 external kink modes have higher growth rates with the nearby ferritic wall. Feedback suppression of kinks is still as effective as before the installation of ferritic material in vessel, in spite of increased mode growth rates.

  5. Myocardial infarction of interior wall: a case study

    Directory of Open Access Journals (Sweden)

    Paweł Musiał

    2015-01-01

    Full Text Available Cardiovascular diseases are the primary death factors of people in the world. Myocardial infarctions and strokes are the most predominant among them. Securing a patient with myocardial infarction requires a rapid pre-hospital procedure and a fast cardiac intervention at an invasive cardiology centre. The paper describes a case of a 55-year-old man diagnosed with acute coronary syndrome with ST-segment elevation myocardial infarction (STEMI, i.e. myocardial infarction of the bottom wall. The operative procedure requires following the MONA algorithm (M – morphine, O – oxygen, N – nitroglycerin, A – aspirin. The process of data tele-transmission is an important element of the pre-hospital proceedings at the level of Medical Emergency Team. It makes it possible to send quickly the ECG record from the ambulance or patient’s home to a cardiology centre.

  6. PAC study of ionic motion in silver compound superionic conductors

    International Nuclear Information System (INIS)

    Mekata, M.; Seguchi, Y.

    1983-01-01

    Ionic motion in superionic conductors, Ag 2 S, Ag 2 Se and Ag 3 SI was investigated by γ-γ PAC on 111 Cd. Diffusion constant measurements showed that probe ions migrate almost as fast as Ag + ions above 500 K in Ag 2 S and Ag 2 Se and above 700 K in Ag 3 SI. Multivalent impurities were found to be unstable in AgI and Ag 2 Te. The correlation time of ionic motion was deduced from the observed relaxation rate together with the diffusion constants. The correlation time and its activation energy increase in order of Ag 2 S, Ag 2 Se and Ag 3 SI. The flight distance of Ag + ions remains almost constant in the measured temperature range. (Auth.)

  7. DEM study of granular flow around blocks attached to inclined walls

    Directory of Open Access Journals (Sweden)

    Samsu Joel

    2017-01-01

    Full Text Available Damage due to intense particle-wall contact in industrial applications can cause severe problems in industries such as mineral processing, mining and metallurgy. Studying the flow dynamics and forces on containing walls can provide valuable feedback for equipment design and optimising operations to prolong the equipment lifetime. Therefore, solids flow-wall interaction phenomena, i.e. induced wall stress and particle flow patterns should be well understood. In this work, discrete element method (DEM is used to study steady state granular flow in a gravity-fed hopper like geometry with blocks attached to an inclined wall. The effects of different geometries, e.g. different wall angles and spacing between blocks are studied by means of a 3D DEM slot model with periodic boundary conditions. The findings of this work include (i flow analysis in terms of flow patterns and particle velocities, (ii force distributions within the model geometry, and (iii wall stress vs. model height diagrams. The model enables easy transfer of the key findings to other industrial applications handling granular materials.

  8. DEM study of granular flow around blocks attached to inclined walls

    Science.gov (United States)

    Samsu, Joel; Zhou, Zongyan; Pinson, David; Chew, Sheng

    2017-06-01

    Damage due to intense particle-wall contact in industrial applications can cause severe problems in industries such as mineral processing, mining and metallurgy. Studying the flow dynamics and forces on containing walls can provide valuable feedback for equipment design and optimising operations to prolong the equipment lifetime. Therefore, solids flow-wall interaction phenomena, i.e. induced wall stress and particle flow patterns should be well understood. In this work, discrete element method (DEM) is used to study steady state granular flow in a gravity-fed hopper like geometry with blocks attached to an inclined wall. The effects of different geometries, e.g. different wall angles and spacing between blocks are studied by means of a 3D DEM slot model with periodic boundary conditions. The findings of this work include (i) flow analysis in terms of flow patterns and particle velocities, (ii) force distributions within the model geometry, and (iii) wall stress vs. model height diagrams. The model enables easy transfer of the key findings to other industrial applications handling granular materials.

  9. Motion-compensating gradients in the study of multiple sclerosis

    International Nuclear Information System (INIS)

    Runge, V.M.; Wood, M.L.; Kaufman, D.L.

    1987-01-01

    A low bandwidth motion compensating technique (no. 1) was compared with a conventional spin-echo technique (no. 2) in 20 patients with multiple sclerosis using a 1.0-T MR imaging system. In technique 1, refocusing gradients were employed to compensate for motion of constant velocity along the frequency-encoding direction. The sampling time was also increased to provide a greater S/N. Use of technique 1 was resulted in detection of 42% +- 23% more lesions (n = 8). The contrast-to-noise ratio for gray versus white matter improved by 87% +- 54% and that for lesion versus white matter by 66% +- 22%. The S/N for white matter improved by 56% +- 25%. An increase in chemical shift artifact was noted but not felt to be detrimental to lesion visualization. In the majority of cases, normal brain stem structures were more distinctly visualized. In two cases, pontine lesions were more clearly demarcated due to reduced pulsation artifacts. The combined use of refocusing gradients and low bandwidth techniques provides reduction of motion artifacts (from CSF and vessel pulsation) and improved S/N, leading to improved lesion detection

  10. Single-unit studies of visual motion processing in cat extrastriate areas

    NARCIS (Netherlands)

    Vajda, Ildiko

    2003-01-01

    Motion vision has high survival value and is a fundamental property of all visual systems. The old Greeks already studied motion vision, but the physiological basis of it first came under scrutiny in the late nineteenth century. Later, with the introduction of single-cell (single-unit)

  11. Experimental Study on the Seismic Performance of Recycled Concrete Brick Walls Embedded with Vertical Reinforcement

    Science.gov (United States)

    Cao, Wanlin; Zhang, Yongbo; Dong, Hongying; Zhou, Zhongyi; Qiao, Qiyun

    2014-01-01

    Recycled concrete brick (RCB) is manufactured by recycled aggregate processed from discarded concrete blocks arising from the demolishing of existing buildings. This paper presents research on the seismic performance of RCB masonry walls to assess the applicability of RCB for use in rural low-rise constructions. The seismic performance of a masonry wall is closely related to the vertical load applied to the wall. Thus, the compressive performance of RCB masonry was investigated firstly by constructing and testing eighteen RCB masonry compressive specimens with different mortar strengths. The load-bearing capacity, deformation and failure characteristic were analyzed, as well. Then, a quasi-static test was carried out to study the seismic behavior of RCB walls by eight RCB masonry walls subjected to an axial compressive load and a reversed cyclic lateral load. Based on the test results, equations for predicting the compressive strength of RCB masonry and the lateral ultimate strength of an RCB masonry wall were proposed. Experimental values were found to be in good agreement with the predicted values. Meanwhile, finite element analysis (FEA) and parametric analysis of the RCB walls were carried out using ABAQUS software. The elastic-plastic deformation characteristics and the lateral load-displacement relations were studied. PMID:28788170

  12. Experimental Study on the Seismic Performance of Recycled Concrete Brick Walls Embedded with Vertical Reinforcement.

    Science.gov (United States)

    Cao, Wanlin; Zhang, Yongbo; Dong, Hongying; Zhou, Zhongyi; Qiao, Qiyun

    2014-08-19

    Recycled concrete brick (RCB) is manufactured by recycled aggregate processed from discarded concrete blocks arising from the demolishing of existing buildings. This paper presents research on the seismic performance of RCB masonry walls to assess the applicability of RCB for use in rural low-rise constructions. The seismic performance of a masonry wall is closely related to the vertical load applied to the wall. Thus, the compressive performance of RCB masonry was investigated firstly by constructing and testing eighteen RCB masonry compressive specimens with different mortar strengths. The load-bearing capacity, deformation and failure characteristic were analyzed, as well. Then, a quasi-static test was carried out to study the seismic behavior of RCB walls by eight RCB masonry walls subjected to an axial compressive load and a reversed cyclic lateral load. Based on the test results, equations for predicting the compressive strength of RCB masonry and the lateral ultimate strength of an RCB masonry wall were proposed. Experimental values were found to be in good agreement with the predicted values. Meanwhile, finite element analysis (FEA) and parametric analysis of the RCB walls were carried out using ABAQUS software. The elastic-plastic deformation characteristics and the lateral load-displacement relations were studied.

  13. Experimental Study on the Seismic Performance of Recycled Concrete Brick Walls Embedded with Vertical Reinforcement

    Directory of Open Access Journals (Sweden)

    Wanlin Cao

    2014-08-01

    Full Text Available Recycled concrete brick (RCB is manufactured by recycled aggregate processed from discarded concrete blocks arising from the demolishing of existing buildings. This paper presents research on the seismic performance of RCB masonry walls to assess the applicability of RCB for use in rural low-rise constructions. The seismic performance of a masonry wall is closely related to the vertical load applied to the wall. Thus, the compressive performance of RCB masonry was investigated firstly by constructing and testing eighteen RCB masonry compressive specimens with different mortar strengths. The load-bearing capacity, deformation and failure characteristic were analyzed, as well. Then, a quasi-static test was carried out to study the seismic behavior of RCB walls by eight RCB masonry walls subjected to an axial compressive load and a reversed cyclic lateral load. Based on the test results, equations for predicting the compressive strength of RCB masonry and the lateral ultimate strength of an RCB masonry wall were proposed. Experimental values were found to be in good agreement with the predicted values. Meanwhile, finite element analysis (FEA and parametric analysis of the RCB walls were carried out using ABAQUS software. The elastic-plastic deformation characteristics and the lateral load-displacement relations were studied.

  14. Experimental study on the seismic performance of new sandwich masonry walls

    Science.gov (United States)

    Xiao, Jianzhuang; Pu, Jie; Hu, Yongzhong

    2013-03-01

    Sandwich masonry walls are widely used as energy-saving panels since the interlayer between the outer leaves can act as an insulation layer. New types of sandwich walls are continually being introduced in research and applications, and due to their unique bond patterns, experimental studies have been performed to investigate their mechanical properties, especially with regard to their seismic performance. In this study, three new types of sandwich masonry wall have been designed, and cyclic lateral loading tests were carried out on five specimens. The results showed that the specimens failed mainly due to slippage along the bottom cracks or the development of diagonal cracks, and the failure patterns were considerably influenced by the aspect ratio. Analysis was undertaken on the seismic response of the new walls, which included ductility, stiffness degradation and energy dissipation capacity, and no obvious difference was observed between the seismic performance of the new walls and traditional walls. Comparisons were made between the experimental results and the calculated results of the shear capacity. It is concluded that the formulas in the two Chinese codes (GB 50011 and GB 50003) are suitable for the calculation of the shear capacity for the new types of walls, and the formula in GB 50011 tends to be more conservative.

  15. A Study on the Performance of Low Cost MEMS Sensors in Strong Motion Studies

    Science.gov (United States)

    Tanırcan, Gulum; Alçık, Hakan; Kaya, Yavuz; Beyen, Kemal

    2017-04-01

    Recent advances in sensors have helped the growth of local networks. In recent years, many Micro Electro Mechanical System (MEMS)-based accelerometers have been successfully used in seismology and earthquake engineering projects. This is basically due to the increased precision obtained in these downsized instruments. Moreover, they are cheaper alternatives to force-balance type accelerometers. In Turkey, though MEMS-based accelerometers have been used in various individual applications such as magnitude and location determination of earthquakes, structural health monitoring, earthquake early warning systems, MEMS-based strong motion networks are not currently available in other populated areas of the country. Motivation of this study comes from the fact that, if MEMS sensors are qualified to record strong motion parameters of large earthquakes, a dense network can be formed in an affordable price at highly populated areas. The goals of this study are 1) to test the performance of MEMS sensors, which are available in the inventory of the Institute through shake table tests, and 2) to setup a small scale network for observing online data transfer speed to a trusted in-house routine. In order to evaluate the suitability of sensors in strong motion related studies, MEMS sensors and a reference sensor are tested under excitations of sweeping waves as well as scaled earthquake recordings. Amplitude response and correlation coefficients versus frequencies are compared. As for earthquake recordings, comparisons are carried out in terms of strong motion(SM) parameters (PGA, PGV, AI, CAV) and elastic response of structures (Sa). Furthermore, this paper also focuses on sensitivity and selectivity for sensor performances in time-frequency domain to compare different sensing characteristics and analyzes the basic strong motion parameters that influence the design majors. Results show that the cheapest MEMS sensors under investigation are able to record the mid

  16. Experimental studies of tearing mode and resistive wall mode dynamics in the reversed field pinch configuration

    International Nuclear Information System (INIS)

    Malmberg, Jenny-Ann

    2003-06-01

    It is relatively straightforward to establish equilibrium in magnetically confined plasmas, but the plasma is frequently susceptible to a variety of instabilities that are driven by the free energy in the magnetic field or in the pressure gradient. These unstable modes exhibit effects that affect the particle, momentum and heat confinement properties of the configuration. Studies of the dynamics of several of the most important modes are the subject of this thesis. The studies are carried out on plasmas in the reversed field pinch (RFP) configuration. One phenomenon commonly observed in RFPs is mode wall locking. The localized nature of these phase- and wall locked structures results in localized power loads on the wall which are detrimental for confinement. A detailed study of the wall locked mode phenomenon is performed based on magnetic measurements from three RFP devices. The two possible mechanisms for wall locking are investigated. Locking as a result of tearing modes interacting with a static field error and locking due to the presence of a non-ideal boundary. The characteristics of the wall locked mode are qualitatively similar in a device with a conducting shell system (TPE-RX) compared to a device with a resistive shell (Extrap T2). A theoretical model is used for evaluating the threshold values for wall locking due to eddy currents in the vacuum vessel in these devices. A good correlation with experiment is observed for the conducting shell device. The possibility of successfully sustaining discharges in a resistive shell RFP is introduced in the recently rebuilt device Extrap T2R. Fast spontaneous mode rotation is observed, resulting in low magnetic fluctuations, low loop voltage and improved confinement. Wall locking is rarely observed. The low tearing mode amplitudes allow for the theoretically predicted internal non-resonant on-axis resistive wall modes to be observed. These modes have not previously been distinguished due to the formation of wall

  17. Hydrogen-isotope motion in scandium studied by ultrasonic measurements

    International Nuclear Information System (INIS)

    Leisure, R.G.; Schwarz, R.B.; Migliori, A.; Torgeson, D.R.; Svare, I.

    1993-01-01

    Resonant ultrasound spectroscopy has been used to investigate ultrasonic attenuation in single crystals of Sc, ScH 0.25 , and ScD 0.18 over the temperature range of 10--300 K for frequencies near 1 MHz. Ultrasonic-attenuation peaks were observed in the samples containing H or D with the maximum attenuation occurring near 25 K for ScH 0.25 and near 50 K for ScD 0.18 . The general features of the data suggest that the motion reflected in the ultrasonic attenuation is closely related to the low-temperature motion seen in nulcear-magnetic-resonance spin-lattice-relaxation measurements. The ultrasonic results were fit with a two-level-system (TLS) model involving tunneling between highly asymmetric sites. The relaxation of the TLS was found to consist of two parts: a weakly temperature-dependent part, probably due to coupling to electrons; and a much more strongly temperature-dependent part, attributed to multiple-phonon processes. The strongly temperature-dependent part was almost two orders of magnitude faster in ScH 0.25 than in ScD 0.18 , in accordance with the idea that tunneling is involved in the motion. Surprisingly, the weakly temperature-dependent part was found to be about the same for the two isotopes. The asymmetries primarily responsible for coupling the TLS to the ultrasound are attributed to interactions between hydrogen ions that lie on adjacent c axes. The results are consistent with an isotope-independent strength for the coupling of the TLS to the ultrasound

  18. Quantitative assessment of regional left ventricular motion using endocardial landmarks

    NARCIS (Netherlands)

    C.J. Slager (Cornelis); T.E.H. Hooghoudt (Ton); P.W.J.C. Serruys (Patrick); J.C.H. Schuurbiers (Johan); J.H.C. Reiber (Johan); G.T. Meester (Geert); P.D. Verdouw (Pieter); P.G. Hugenholtz (Paul)

    1986-01-01

    textabstractIn this study the hypothesis is tested that the motion pattern of small anatomic landmarks, recognizable at the left ventricular endocardial border in the contrast angiocardiogram, reflects the motion of the endocardial wall. To verify this, minute metal markers were inserted in the

  19. SU-F-T-337: Accounting for Patient Motion During Volumetric Modulated Ac Therapy (VMAT) Planning for Post Mastectomy Chest Wall Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, M; Fontenot, J [Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States); Heins, D [Louisiana State University, Baton Rouge, LA (United States)

    2016-06-15

    Purpose: To evaluate two dose optimization strategies for maintaining target volume coverage of inversely-planned post mastectomy radiotherapy (PMRT) plans during patient motion. Methods: Five patients previously treated with VMAT for PMRT at our clinical were randomly selected for this study. For each patient, two plan optimization strategies were compared. Plan 1 was optimized to a volume that included the physician’s planning target volume (PTV) plus an expansion up to 0.3 cm from the bolus surface. Plan 2 was optimized to the PTV plus an expansion up to 0.3 cm from the patient surface (i.e., not extending into the bolus). VMAT plans were optimized to deliver 95% of the prescription to 95% of the PTV while sparing organs at risk based on clinical dose limits. PTV coverage was then evaluated following the simulation of patient shifts by 1.0 cm in the anterior and posterior directions using the treatment planning system. Results: Posterior patient shifts produced a difference in D95% of around 11% in both planning approaches from the non-shifted dose distributions. Coverage of the medial and lateral borders of the evaluation volume was reduced in both the posteriorly shifted plans (Plan 1 and Plan 2). Anterior patient shifts affected Plan 2 more than Plan 1 with a difference in D95% of 1% for Plan 1 versus 6% for Plan 2 from the non-shifted dose distributions. The least variation in PTV dose homogeneity for both shifts was obtained with Plan 1. However, all posteriorly shifted plans failed to deliver 95% of the prescription to 95% of the PTV. Whereas, only a few anteriorly shifted plans failed this criteria. Conclusion: The results of this study suggest both planning volume methods are sensitive to patient motion, but that a PTV extended into a bolus volume is slightly more robust for anterior patient shifts.

  20. SU-F-T-337: Accounting for Patient Motion During Volumetric Modulated Ac Therapy (VMAT) Planning for Post Mastectomy Chest Wall Irradiation

    International Nuclear Information System (INIS)

    Hernandez, M; Fontenot, J; Heins, D

    2016-01-01

    Purpose: To evaluate two dose optimization strategies for maintaining target volume coverage of inversely-planned post mastectomy radiotherapy (PMRT) plans during patient motion. Methods: Five patients previously treated with VMAT for PMRT at our clinical were randomly selected for this study. For each patient, two plan optimization strategies were compared. Plan 1 was optimized to a volume that included the physician’s planning target volume (PTV) plus an expansion up to 0.3 cm from the bolus surface. Plan 2 was optimized to the PTV plus an expansion up to 0.3 cm from the patient surface (i.e., not extending into the bolus). VMAT plans were optimized to deliver 95% of the prescription to 95% of the PTV while sparing organs at risk based on clinical dose limits. PTV coverage was then evaluated following the simulation of patient shifts by 1.0 cm in the anterior and posterior directions using the treatment planning system. Results: Posterior patient shifts produced a difference in D95% of around 11% in both planning approaches from the non-shifted dose distributions. Coverage of the medial and lateral borders of the evaluation volume was reduced in both the posteriorly shifted plans (Plan 1 and Plan 2). Anterior patient shifts affected Plan 2 more than Plan 1 with a difference in D95% of 1% for Plan 1 versus 6% for Plan 2 from the non-shifted dose distributions. The least variation in PTV dose homogeneity for both shifts was obtained with Plan 1. However, all posteriorly shifted plans failed to deliver 95% of the prescription to 95% of the PTV. Whereas, only a few anteriorly shifted plans failed this criteria. Conclusion: The results of this study suggest both planning volume methods are sensitive to patient motion, but that a PTV extended into a bolus volume is slightly more robust for anterior patient shifts.

  1. Study of two-dimensional Debye clusters using Brownian motion

    International Nuclear Information System (INIS)

    Sheridan, T.E.; Theisen, W.L.

    2006-01-01

    A two-dimensional Debye cluster is a system of n identical particles confined in a parabolic well and interacting through a screened Coulomb (i.e., a Debye-Hueckel or Yukawa) potential with a Debye length λ. Experiments were performed for 27 clusters with n=3-63 particles (9 μm diam) in a capacitively coupled 9 W rf discharge at a neutral argon pressure of 13.6 mTorr. In the strong-coupling regime each particle exhibits small amplitude Brownian motion about its equilibrium position. These motions were projected onto the center-of-mass and breathing modes and Fourier analyzed to give resonance curves from which the mode frequencies, amplitudes, and damping rates were determined. The ratio of the breathing frequency to the center-of-mass frequency was compared with theory to self-consistently determine the Debye shielding parameter κ, Debye length λ, particle charge q, and mode temperatures. It is found that 1 < or approx. κ < or approx. 2, and κ decreases weakly with n. The particle charge averaged over all measurements is -14 200±200 e, and q decreases slightly with n. The two center-of-mass modes and the breathing mode are found to have the same temperature, indicating that the clusters are in thermal equilibrium with the neutral gas. The average cluster temperature is 399±5 K

  2. Influence of cold walls on PET image quantification and volume segmentation: A phantom study

    International Nuclear Information System (INIS)

    Berthon, B.; Marshall, C.; Edwards, A.; Spezi, E.; Evans, M.

    2013-01-01

    Purpose: Commercially available fillable plastic inserts used in positron emission tomography phantoms usually have thick plastic walls, separating their content from the background activity. These “cold” walls can modify the intensity values of neighboring active regions due to the partial volume effect, resulting in errors in the estimation of standardized uptake values. Numerous papers suggest that this is an issue for phantom work simulating tumor tissue, quality control, and calibration work. This study aims to investigate the influence of the cold plastic wall thickness on the quantification of 18F-fluorodeoxyglucose on the image activity recovery and on the performance of advanced automatic segmentation algorithms for the delineation of active regions delimited by plastic walls.Methods: A commercial set of six spheres of different diameters was replicated using a manufacturing technique which achieves a reduction in plastic walls thickness of up to 90%, while keeping the same internal volume. Both sets of thin- and thick-wall inserts were imaged simultaneously in a custom phantom for six different tumor-to-background ratios. Intensity values were compared in terms of mean and maximum standardized uptake values (SUVs) in the spheres and mean SUV of the hottest 1 ml region (SUV max , SUV mean , and SUV peak ). The recovery coefficient (RC) was also derived for each sphere. The results were compared against the values predicted by a theoretical model of the PET-intensity profiles for the same tumor-to-background ratios (TBRs), sphere sizes, and wall thicknesses. In addition, ten automatic segmentation methods, written in house, were applied to both thin- and thick-wall inserts. The contours obtained were compared to computed tomography derived gold standard (“ground truth”), using five different accuracy metrics.Results: The authors' results showed that thin-wall inserts achieved significantly higher SUV mean , SUV max , and RC values (up to 25%, 16

  3. A method of meta-mechanism combination and replacement based on motion study

    Directory of Open Access Journals (Sweden)

    Yadong Fang

    2015-01-01

    Full Text Available Lacking the effective methods to reduce labor and cost, many small- and medium-sized assembly companies are facing with the problem of high cost for a long time. In order to reduce costs of manual operations, the method of meta-mechanism combination and replacement is studied. In this paper, we mainly discuss assembling motion analysis, workpieces position information acquisition, motion library construction, assembling motion analysis by Maynard’s operation sequence technique, meta-mechanism database establishment, and match of motion and mechanism. At the same time, the principle, process, and system realization framework of mechanism replacement are introduced. Lastly, problems for low-cost automation of the production line are basically resolved by operator motion analysis and meta-mechanism combination and match.

  4. Motion sickness and otolith sensitivity - A pilot study of habituation to linear acceleration

    Science.gov (United States)

    Potvin, A. R.; Sadoff, M.; Billingham, J.

    1977-01-01

    Astronauts, particularly in Skylab flights, experienced varying degrees of motion sickness lasting 3-5 days. One possible mechanism for this motion sickness adaptation is believed to be a reduction in otolith sensitivity with an attendant reduction in sensory conflict. In an attempt to determine if this hypothesis is valid, a ground-based pilot study was conducted on a vertical linear accelerator. The extent of habituation to accelerations which initially produced motion sickness was evaluated, along with the possible value of habituation training to minimize the space motion sickness problem. Results showed that habituation occurred for 6 of the 8 subjects tested. However, in tests designed to measure dynamic and static otolith function, no significant differences between pre- and post-habituation tests were observed. Cross habituation effects to a standard Coriolis acceleration test were not significant. It is unlikely that ground-based pre-habituation to linear accelerations of the type examined would alter susceptibility to space motion sickness.

  5. Electron spin echo studies of the internal motion of radicals in crystals: Phase memory vs correlation time

    International Nuclear Information System (INIS)

    Kispert, L.D.; Bowman, M.K.; Norris, J.R.; Brown, M.S.

    1982-01-01

    An electron spin echo (ESE) study of the internal motion of the CH 2 protons in irradiated zinc acetate dihydrate crystals shows that quantitative measurements of the motional correlation time can be obtained quite directly from pulsed measurements. In the slow motional limit, the motional correlation time is equal to the phase memory time determined by ESE. In the fast motional limit, the motional correlation time is proportional to the no motion spectral second moment divided by the ESE phase memory time. ESE offers a convenient method of studying motion, electron transfer, conductivity, etc. in a variety of systems too complicated for study by ordinary EPR. New systems for study by ESE include biological samples, organic polymers, liquid solutions of radicals with unresolved hyperfine, etc. When motion modulates large anisotropic hyperfine couplings, ESE measurements of the phase memory time are sensitive to modulation of pseudosecular hyperfine interactions

  6. SU-F-J-119: Pilot Study On the Location-Based Lung Motion Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, TK [Procure Proton Therapy Center, Oklahoma City, OK (United States); Ewald, A [McLaren Cancer Institute, Flint, MI (United States)

    2016-06-15

    Purpose: In most of lung treatment cases with various radiotherapy beam modalities, 4DCT images are obtained in order to define ITV. ITV is defined with the signal from motion monitoring system, e.g. RPM. However, the signal is not consistent with tumor motion because it varies with location, its size, age, gender, etc. In the present study, the location-based motion assessment is presented. Methods: 4DCT images of 70 patients were reviewed: 28-left-lung and 42-right-lung patients; 36-female and 34-male patients; the age range of 51.2–89.9; tumor-size range of 0.75–9.50cm with 25% of these adherent to bony-anatomy. Philips Big-Bore Simulation CT and RPM systems were used. The study was performed as follows. First, RPM signal and tumor motion in superior-inferior direction was compared. Second, the tumor size and its motion amplitude in all directions were measured at multiple locations. Third, the average tumor motion was calculated to assess general motion amplitudes at various locations. Results: RPM amplitude is not consistent with lung tumor motion amplitude. The tumors of similar sizes at similar location present various motion amplitude up to 1.1cm difference, but in average, the standard deviation was <0.5cm. Almost regardless of tumor sizes, the tumor motion was greatest at lower lobe location (>=1.0cm), and the smallest at upper lobe location and when adherent to bony-anatomy (<=0.5cm). Conclusion: The tumor size affects the motion amplitude less than does the tumor location. However, as the study results indicate that tumor motion has noticeable variation and so further study with more patient cases is needed. Also, for the same patient, the RPM signal presents instability of breathing, and clinically the patient with the instability of RPM breathing of <=10% is selected for respiratory-gated radiotherapy and ∼25% of patients under current study was treated. Patient-specific motion-uncertainty margins are considered to be added following further

  7. Analytical Study on the Beyond Design Seismic Capacity of Reinforced Concrete Shear Walls

    Energy Technology Data Exchange (ETDEWEB)

    Nugroho, Tino Sawaldi Adi [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Chi, Ho-Seok [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    The OECD-NEA has organized an international benchmarking program to better understand this critical issue. The benchmark program provides test specimen geometry, test setup, material properties, loading conditions, recorded measures, and observations of the test specimens. The main objective of this research is to assess the beyond design seismic capacity of the reinforced concrete shear walls tested at the European Laboratory for Structural Assessment between 1997 and 1998 through participation in the OECD-NEA benchmark program. In this study, assessing the beyond design seismic capacity of reinforced concrete shear walls is performed analytically by comparing numerical results with experimental results. The seismic shear capacity of the reinforced concrete shear wall was predicted reasonably well using ABAQUS program. However, the proper calibration of the concrete material model was necessary for better prediction of the behavior of the reinforced concrete shear walls since the response was influenced significantly by the material constitutive model.

  8. A micromagnetic study of the oscillations of pinned domain walls in magnetic ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Alejos, Oscar [Dpto. Electricidad y Electronica, Universidad de Valladolid, 47071 Valladolid (Spain)]. E-mail: oscaral@ee.uva.es; Torres, Carlos [Dpto. Electricidad y Electronica, Universidad de Valladolid, 47071 Valladolid (Spain); Hernandez-Gomez, Pablo [Dpto. Electricidad y Electronica, Universidad de Valladolid, 47071 Valladolid (Spain); Lopez-Diaz, Luis [Dpto. Fisica Aplicada, Universidad de Salamanca, 37071 Salamanca (Spain); Torres, Luis [Dpto. Fisica Aplicada, Universidad de Salamanca, 37071 Salamanca (Spain); Martinez, Eduardo [Dpto. Ingenieria Electromecanica, Universidad de Burgos, 09001 Burgos (Spain)

    2007-09-15

    The work studies the dynamics of domain walls in magnetic ribbons with thicknesses of the order of magnitude of the permalloy exchange length (5.7 nm) by means of micromagnetic simulations. Two small defects are symmetrically placed on both edges of the ribbon, one on each edge, occupying the whole ribbon thickness. One transverse domain wall is pinned by the defects, in a head-to-head configuration. A free wall oscillation is forced by applying a static external magnetic field in the direction of the large axis until the wall reaches a new equilibrium position (elongation), and then removed. Three dynamic regimes are observed depending on the size of the cross ribbon section.

  9. A micromagnetic study of the oscillations of pinned domain walls in magnetic ribbons

    International Nuclear Information System (INIS)

    Alejos, Oscar; Torres, Carlos; Hernandez-Gomez, Pablo; Lopez-Diaz, Luis; Torres, Luis; Martinez, Eduardo

    2007-01-01

    The work studies the dynamics of domain walls in magnetic ribbons with thicknesses of the order of magnitude of the permalloy exchange length (5.7 nm) by means of micromagnetic simulations. Two small defects are symmetrically placed on both edges of the ribbon, one on each edge, occupying the whole ribbon thickness. One transverse domain wall is pinned by the defects, in a head-to-head configuration. A free wall oscillation is forced by applying a static external magnetic field in the direction of the large axis until the wall reaches a new equilibrium position (elongation), and then removed. Three dynamic regimes are observed depending on the size of the cross ribbon section

  10. A fundamental study of fission product deposition on the wall surface

    International Nuclear Information System (INIS)

    Ishiguro, R.; Sakashita, H.; Sugiyama, K.

    1987-01-01

    Deposition of soluble matters on wall surfaces is studied in the present report for the purpose to understand a mechanism of fission product deposition on the wall surface in a molten salt reactor. Calcium carbonate solution is used to observe the fundamental mechanism of deposition. The experiments are performed under conditions of turbulent flow of the solution over a heated wall. According to the experimental results a model is proposed to estimate deposition rate. The model consists of two parts, one is the initial nucleus formation on a clean wall surface and the other is the constant increase of deposition succeeding to the first stage. The model is assessed by comparing it with the experimental results. Both results coincide well in some parameters, but not so well in others. (author)

  11. The plant cell wall integrity maintenance mechanism--a case study of a cell wall plasma membrane signaling network.

    Science.gov (United States)

    Hamann, Thorsten

    2015-04-01

    Some of the most important functions of plant cell walls are protection against biotic/abiotic stress and structural support during growth and development. A prerequisite for plant cell walls to perform these functions is the ability to perceive different types of stimuli in both qualitative and quantitative manners and initiate appropriate responses. The responses in turn involve adaptive changes in cellular and cell wall metabolism leading to modifications in the structures originally required for perception. While our knowledge about the underlying plant mechanisms is limited, results from Saccharomyces cerevisiae suggest the cell wall integrity maintenance mechanism represents an excellent example to illustrate how the molecular mechanisms responsible for stimulus perception, signal transduction and integration can function. Here I will review the available knowledge about the yeast cell wall integrity maintenance system for illustration purposes, summarize the limited knowledge available about the corresponding plant mechanism and discuss the relevance of the plant cell wall integrity maintenance mechanism in biotic stress responses. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. A Prospective Cohort Study of Gated Stereotactic Liver Radiation Therapy Using Continuous Internal Electromagnetic Motion Monitoring

    DEFF Research Database (Denmark)

    Worm, Esben S; Høyer, Morten; Hansen, Rune

    2018-01-01

    PURPOSE: Intrafraction motion can compromise the treatment accuracy in liver stereotactic body radiation therapy (SBRT). Respiratory gating can improve treatment delivery; however, gating based on external motion surrogates is inaccurate. The present study reports the use of Calypso-based internal...... electromagnetic motion monitoring for gated liver SBRT. METHODS AND MATERIALS: Fifteen patients were included in a study of 3-fraction respiratory gated liver SBRT guided by 3 implanted electromagnetic transponders. The planning target volume was created by a 5-mm axial and 7-mm (n = 12) or 10-mm (n = 3...

  13. A study on synchronously whirling motion of hydrodynamic journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2001-01-01

    In this paper, a control algorithm which is synchronously excitation the bearing with whirl speed of rotor is employed to suppress the whirl instability and unbalance response of the rotor-bearing system. Also, the cavitation algorithm implementing the Jakobsson-Floberg-Olsson boundary condition is adopted to predict cavitation regions in the fluid film more accurately than a conventional analysis with the Renolds condition. The stabilities and unbalance responses of the rotor-bearing system are investigated for various control gains and phase differences between the bearing and journal motion. It is shown that the unbalance response of the system can be greatly improved by synchronous control of the bearing, and there is an optimum phase difference, which gives the minimum unbalance response of the system, for given operating condition. It is also found that the onset speed of the instability can be greatly increased by synchronous control of the bearing

  14. A study on synchronously whirling motion of hydrodynamic journal bearings

    Energy Technology Data Exchange (ETDEWEB)

    Rho, Byoung Hoo; Kim, Kyung Woong [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    2001-09-01

    In this paper, a control algorithm which is synchronously excitation the bearing with whirl speed of rotor is employed to suppress the whirl instability and unbalance response of the rotor-bearing system. Also, the cavitation algorithm implementing the Jakobsson-Floberg-Olsson boundary condition is adopted to predict cavitation regions in the fluid film more accurately than a conventional analysis with the Renolds condition. The stabilities and unbalance responses of the rotor-bearing system are investigated for various control gains and phase differences between the bearing and journal motion. It is shown that the unbalance response of the system can be greatly improved by synchronous control of the bearing, and there is an optimum phase difference, which gives the minimum unbalance response of the system, for given operating condition. It is also found that the onset speed of the instability can be greatly increased by synchronous control of the bearing.

  15. An integrated study for mapping the moisture distribution in an ancient damaged wall painting.

    Science.gov (United States)

    Capitani, Donatella; Proietti, Noemi; Gobbino, Marco; Soroldoni, Luigi; Casellato, Umberto; Valentini, Massimo; Rosina, Elisabetta

    2009-12-01

    An integrated study of microclimate monitoring, IR thermography (IRT), gravimetric tests and portable unilateral nuclear magnetic resonance (NMR) was applied in the framework of planning emergency intervention on a very deteriorated wall painting in San Rocco church, Cornaredo (Milan, Italy). The IRT investigation supported by gravimetric tests showed that the worst damage, due to water infiltration, was localized on the wall painting of the northern wall. Unilateral NMR, a new non-destructive technique which measures the hydrogen signal of the moisture and that was applied directly to the wall, allowed a detailed map of the distribution of the moisture in the plaster underlying the wall panting to be obtained. With a proper calibration of the integral of the recorded signal with suitable specimens, each area of the map corresponded to an accurate amount of moisture. IRT, gravimetric tests and unilateral NMR applied to investigate the northern wall painting showed the presence of two wet areas separated by a dry area. The moisture found in the lower area was ascribed to the occurrence of rising damp at the bottom of the wall due to the slope of the garden soil towards the northern exterior. The moisture found in the upper area was ascribed to condensation phenomena associated with the presence of a considerable amount of soluble, hygroscopic salts. In the framework of this integrated study, IRT investigation and gravimetric methods validated portable unilateral NMR as a new analytical tool for measuring in situ and without any sampling of the distribution and amount of moisture in wall paintings.

  16. Comparative study of diastolic filling under varying left ventricular wall stiffness

    Science.gov (United States)

    Mekala, Pritam; Santhanakrishnan, Arvind

    2014-11-01

    Pathological remodeling of the human cardiac left ventricle (LV) is observed in hypertensive heart failure as a result of pressure overload. Myocardial stiffening occurs in these patients prior to chronic maladaptive changes, resulting in increased LV wall stiffness. The goal of this study was to investigate the change in intraventricular filling fluid dynamics inside a physical model of the LV as a function of wall stiffness. Three LV models of varying wall stiffness were incorporated into an in vitro flow circuit driven by a programmable piston pump. Windkessel elements were used to tune the inflow and systemic pressure in the model with least stiffness to match healthy conditions. Models with stiffer walls were comparatively tested maintaining circuit compliance, resistance and pump amplitude constant. 2D phase-locked PIV measurements along the central plane showed that with increase in wall stiffness, the peak velocity and cardiac output inside the LV decreased. Further, inflow vortex ring propagation toward the LV apex was reduced with increasing stiffness. The above findings indicate the importance of considering LV wall relaxation characteristics in pathological studies of filling fluid dynamics.

  17. A preliminary study on the local impact behavior of Steel-plate Concrete walls

    International Nuclear Information System (INIS)

    Kim, Kap-sun; Moon, Il-hwan; Choi, Hyung-jin; Nam, Deok-woo

    2017-01-01

    International regulations for nuclear power plants strictly prescribe the design requirements for local impact loads, such as aircraft engine impact, and internal and external missile impact. However, the local impact characteristics of Steel-plate Concrete (SC) walls are not easy to evaluate precisely because the dynamic impact behavior of SC walls which include external steel plate, internal concrete, tie-bars, and studs, is so complex. In this study, dynamic impact characteristics of SC walls subjected to local missile impact load are investigated via actual high-speed impact test and numerical simulation. Three velocity checkout tests and four SC wall tests were performed at the Energetic Materials Research and Testing Center (EMRTC) site in the USA. Initial and residual velocity of the missile, strain and acceleration of the back plate, local failure mode (penetration, bulging, splitting and perforation) and deformation size, etc. were measured to study the local behavior of the specimen using high speed cameras and various other instrumentation devices. In addition, a more advanced and applicable numerical simulation method using the finite element (FE) method is proposed and verified by the experimental results. Finally, the experimental results are compared with the local failure evaluation formula for SC walls recently proposed, and future research directions for the development of a refined design method for SC walls are reviewed.

  18. Study on fluidity of squeeze cast AZ91D magnesium alloy with different wall thicknesses

    Directory of Open Access Journals (Sweden)

    Chen Yun

    2014-03-01

    Full Text Available Rectangular cross-section specimens with different section thicknesses were prepared to study the influences of pouring temperature, mould temperature and squeeze velocity on the fluidity of squeeze cast AZ91D magnesium alloy by means of orthogonal test design method. The results show that pouring temperature, mould temperature and squeeze velocity can significantly affect the fluidity of magnesium alloy specimens with wall thickness no more than 4 mm, and the pouring temperature is the most influential factor on the fluidity of specimens with wall thickness of 1, 2 and 3 mm, while mould temperature is the one for specimens with wall thickness of 4 mm. Increasing pouring temperature between 700 °C and 750 °C is beneficial to the fluidity of AZ91D magnesium alloy, and increasing mould temperature significantly enhances the filling ability of thick (3 and 4 mm section castings. The fluidity of squeeze cast magnesium alloy increases with the increase of wall thickness. It is not recommended to produce magnesium alloy casting with wall thickness of smaller than 3 mm by squeeze cast process due to the poor fluidity. The software DPS was used to generate the regression model, and linear regression equations of the fluidity of squeeze cast AZ91D with different wall thicknesses are obtained using the test results.

  19. Wall Turbulence.

    Science.gov (United States)

    Hanratty, Thomas J.

    1980-01-01

    This paper gives an account of research on the structure of turbulence close to a solid boundary. Included is a method to study the flow close to the wall of a pipe without interferring with it. (Author/JN)

  20. Improving pulse oximetry accuracy by removing motion artifacts from photoplethysmograms using relative sensor motion: a preliminary study

    NARCIS (Netherlands)

    Wijshoff, R.W.C.G.R.; Mischi, M.; Woerlee, P.H.; Aarts, R.M.; Van Huffel, S.; Naelaers, G.; Caicedo, A.; Bruley, D.F.; Harrison, D.K.

    2013-01-01

    To expand applicability of pulse oximetry in low-acuity ambulatory settings, the impact of motion on extracted parameters as saturation (SpO2) and pulse rate (PR) needs to be reduced. We hypothesized that sensor motion relative to the skin can be used as an artifact reference in a correlation

  1. MRI-assisted PET motion correction for neurologic studies in an integrated MR-PET scanner.

    Science.gov (United States)

    Catana, Ciprian; Benner, Thomas; van der Kouwe, Andre; Byars, Larry; Hamm, Michael; Chonde, Daniel B; Michel, Christian J; El Fakhri, Georges; Schmand, Matthias; Sorensen, A Gregory

    2011-01-01

    Head motion is difficult to avoid in long PET studies, degrading the image quality and offsetting the benefit of using a high-resolution scanner. As a potential solution in an integrated MR-PET scanner, the simultaneously acquired MRI data can be used for motion tracking. In this work, a novel algorithm for data processing and rigid-body motion correction (MC) for the MRI-compatible BrainPET prototype scanner is described, and proof-of-principle phantom and human studies are presented. To account for motion, the PET prompt and random coincidences and sensitivity data for postnormalization were processed in the line-of-response (LOR) space according to the MRI-derived motion estimates. The processing time on the standard BrainPET workstation is approximately 16 s for each motion estimate. After rebinning in the sinogram space, the motion corrected data were summed, and the PET volume was reconstructed using the attenuation and scatter sinograms in the reference position. The accuracy of the MC algorithm was first tested using a Hoffman phantom. Next, human volunteer studies were performed, and motion estimates were obtained using 2 high-temporal-resolution MRI-based motion-tracking techniques. After accounting for the misalignment between the 2 scanners, perfectly coregistered MRI and PET volumes were reproducibly obtained. The MRI output gates inserted into the PET list-mode allow the temporal correlation of the 2 datasets within 0.2 ms. The Hoffman phantom volume reconstructed by processing the PET data in the LOR space was similar to the one obtained by processing the data using the standard methods and applying the MC in the image space, demonstrating the quantitative accuracy of the procedure. In human volunteer studies, motion estimates were obtained from echo planar imaging and cloverleaf navigator sequences every 3 s and 20 ms, respectively. Motion-deblurred PET images, with excellent delineation of specific brain structures, were obtained using these 2 MRI

  2. Study on scaling law of PWR natural circulation with motion condition

    International Nuclear Information System (INIS)

    Lu Donghua; Xiao Zejun; Chen Bingde

    2009-01-01

    For some nuclear reactors installed on automobiles, boats or deep sea vehicles, it is an important way to investigate their system safety by performing natural circulation experiments under motion condition. This paper studied the natural circulation on moving plants based on work of static natural circulation scaling method. With rigid motion theory, acceleration at each point was obtained on primary system and introduced to momentum equation. Thus a set of motion similar criteria were obtained. Furthermore, equal and unequal height simulation were analyzed. As to the unequal one, non isochronous simulation was needed for displacement and angular acceleration. (authors)

  3. Broad line and pulsed NMR study of molecular motion in furfuryl alcohol resins

    International Nuclear Information System (INIS)

    Glowinkowski, S.; Pajak, Z.

    1978-01-01

    Broad line and pulsed nuclear magnetic resonance studies are carried out on a number of furfuryl alcohol resins differentiated by viscosity. Proton NMR spectra and relaxation times T 1 and Tsub(1rho) are measured over a wide temperature range and the results are interpreted in terms of molecular motion. The marked decrease in second moment and existence of high temperature spin-lattice relaxation times minima are presumed to result from rotational motion of polymer chains. The relaxation processes at low temperature are believed to be due to rotational motion of methyl endgroup and paramagnetic centres. (author)

  4. Influence of PCMs on thermal behavior of building walls: experimental study using the walls of a reduced scale room

    Directory of Open Access Journals (Sweden)

    Gounni Ayoub

    2017-01-01

    Full Text Available Using Phase-Change Materials (PCM for lightweight building applications can increase equivalent thermal mass and provide energy savings. In the present experimental work, the heat transfer performance testing of some building walls, with or without PCM, is carried out using a reduced-scale cubic room (the test-cell. The cubic cell is heated by an incandescent bulb placed on its centre, and it is housed in an air-conditioned large-scale room that allows to control the ambient air temperature. The effect of the double PCM layer and of its location relatively to the outside surface of the wall is tested and discussed in terms of overall transmitted heat flux and in terms of reduction of the inside and outside surface temperatures. Findings shows that the additional inertia introduced by the PCM leads to a reduced overall heat flux transmission by the wall and to a lesser daily temperature amplitude on the surface of the wall that enhances the thermal comfort inside the building. In the next step of this work, the case of sandwich walls with air gap, and with wood and PCM layers will be considered.

  5. Influence of PCMs on thermal behavior of building walls: experimental study using the walls of a reduced scale room

    Science.gov (United States)

    Gounni, Ayoub; Tahar Mabrouk, Mohamed; Kheiri, Abdelhamid; El alami, Mustapha

    2017-11-01

    Using Phase-Change Materials (PCM) for lightweight building applications can increase equivalent thermal mass and provide energy savings. In the present experimental work, the heat transfer performance testing of some building walls, with or without PCM, is carried out using a reduced-scale cubic room (the test-cell). The cubic cell is heated by an incandescent bulb placed on its centre, and it is housed in an air-conditioned large-scale room that allows to control the ambient air temperature. The effect of the double PCM layer and of its location relatively to the outside surface of the wall is tested and discussed in terms of overall transmitted heat flux and in terms of reduction of the inside and outside surface temperatures. Findings shows that the additional inertia introduced by the PCM leads to a reduced overall heat flux transmission by the wall and to a lesser daily temperature amplitude on the surface of the wall that enhances the thermal comfort inside the building. In the next step of this work, the case of sandwich walls with air gap, and with wood and PCM layers will be considered.

  6. Using Edge Voxel Information to Improve Motion Regression for rs-fMRI Connectivity Studies.

    Science.gov (United States)

    Patriat, Rémi; Molloy, Erin K; Birn, Rasmus M

    2015-11-01

    Recent fMRI studies have outlined the critical impact of in-scanner head motion, particularly on estimates of functional connectivity. Common strategies to reduce the influence of motion include realignment as well as the inclusion of nuisance regressors, such as the 6 realignment parameters, their first derivatives, time-shifted versions of the realignment parameters, and the squared parameters. However, these regressors have limited success at noise reduction. We hypothesized that using nuisance regressors consisting of the principal components (PCs) of edge voxel time series would be better able to capture slice-specific and nonlinear signal changes, thus explaining more variance, improving data quality (i.e., lower DVARS and temporal SNR), and reducing the effect of motion on default-mode network connectivity. Functional MRI data from 22 healthy adult subjects were preprocessed using typical motion regression approaches as well as nuisance regression derived from edge voxel time courses. Results were evaluated in the presence and absence of both global signal regression and motion censoring. Nuisance regressors derived from signal intensity time courses at the edge of the brain significantly improved motion correction compared to using only the realignment parameters and their derivatives. Of the models tested, only the edge voxel regression models were able to eliminate significant differences in default-mode network connectivity between high- and low-motion subjects regardless of the use of global signal regression or censoring.

  7. Discrimination of animate and inanimate motion in 9-month-old infants: an ERP study.

    Science.gov (United States)

    Kaduk, Katharina; Elsner, Birgit; Reid, Vincent M

    2013-10-01

    Simple geometric shapes moving in a self-propelled manner, and violating Newtonian laws of motion by acting against gravitational forces tend to induce a judgement that an object is animate. Objects that change their motion only due to external causes are more likely judged as inanimate. How the developing brain is employed in the perception of animacy in early ontogeny is currently unknown. The aim of this study was to use ERP techniques to determine if the negative central component (Nc), a waveform related to attention allocation, was differentially affected when an infant observed animate or inanimate motion. Short animated movies comprising a marble moving along a marble run either in an animate or an inanimate manner were presented to 15 infants who were 9 months of age. The ERPs were time-locked to a still frame representing animate or inanimate motion that was displayed following each movie. We found that 9-month-olds are able to discriminate between animate and inanimate motion based on motion cues alone and most likely allocate more attentional resources to the inanimate motion. The present data contribute to our understanding of the animate-inanimate distinction and the Nc as a correlate of infant cognitive processing. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Experimental Study of Multi-Walled Composite Shell Fragments under Thermal Force Effects

    Directory of Open Access Journals (Sweden)

    L. P. Tairova

    2015-01-01

    Full Text Available Multi-walled composite shells are a relatively new prospective type of load carrying structures for rocket and space engineering. These CFRP structures are produced by injection and infusion methods and have several advantages in comparison with common structures such as stringer-frame, grid and sandwich structures with a light core. In particular, those have more structural parameters, which enable one to control mechanical properties of the structure, and this is important in designing the load carrying structures of different purpose.Presently, there are few national and foreign publications on experimental investigations of mechanical properties of multi-walled shells. That is why the objective of the paper is to conduct the experimental study of deformation and failure processes of a multi-walled panel both under steady-state heating and under unsteady-state one.The paper presents the results of two tests: (1 the study of deformation and failure modes under compression and complete heating up to a specified temperature and (2 validation of working capability of multi-walled samples under single-side heating and compression simulating a start and flight version of the “ Proton” launch vehicle.Experimental results have shown that average elastic properties of multi-walled samples slightly depend on temperature for the studied range (from room temperature up to 195C while strength properties considerably decrease with increasing temperature, and this is typical for CFRP structures under compression. However, under unsteady-state short-term heating the structure has a strength that exceeds the minimal necessary strength of load carrying structures of the “Proton” launch vehicle (the samples satisfy simulated start conditions of the “Proton” launch vehicle. This is because of a low heat conductivity of the multi-walled core: an unheated sheet holds a low temperature and high load carrying capacity.Obtained results can be used in

  9. Inelastic x-ray study of plasmons in oriented single and multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Casa, D.M.; Upton, M.H.; Gog, T.; Misewich, J.; Hill, J.P.; Lowndes, D.; Eres, G.

    2006-01-01

    Carbon nanotubes (CNT) have a wide variety of interesting properties and a large number of potential aplications in electronic and optical devices. In this study we concentrate on one important aspect of their electronic stucture: the plasmon dispersions in both single- and multi-wall CNTs and their relation to those in graphite. For the first time inelastic X-ray scattering is used to study these collective electronic excitations in oriented CNT samples. The experiments were performed on the IXS instrument at beamline 9ID CMC-XOR, APS, ANL. The incident energy was defined by a Si(333) monochromator, a spherically bent Ge(733) diced analyzer at the end of a 1-m arm focused the incident radiation onto a solid-state detector. The overall resolution was ∼300 meV FWHM. The incident photons were linearly polarized perpendicular to the scattering plane. Energy loss scans were taken by varying the incident energy while keeping the exit energy fixed at 8.9805 keV. The momentum transfer was kept along the nanotubes axis. Spectra were taken at room temperature. The samples were oriented CNTs (both single- and multi-wall) grown on a Si substrate. The samples referred to as 'single-wall' were in fact a few walls at most (1-5) while the multi-walled ones had ∼12 walls. Fig. 1. shows the inelastic spectra for the single-, multi-wall, and highly oriented pyrolithic graphite (HOPG) from top to bottom. Momentum transfer was Q = 0.79 (angstrom) -1 in all cases, its direction was along the tubes for the first two samples or parallel to the sheets for graphite. The peaks at ∼10 and ∼30 eV are known as the π and σ + π plasmons respectively. Fig. 2. shows the complete dispersion curves for both plasmon modes as a function of momentum transfer for all three samples.

  10. A computational fluid dynamics modeling study of guide walls for downstream fish passage

    Science.gov (United States)

    Mulligan, Kevin; Towler, Brett; Haro, Alexander J.; Ahlfeld, David P.

    2017-01-01

    A partial-depth, impermeable guidance structure (or guide wall) for downstream fish passage is typically constructed as a series of panels attached to a floating boom and anchored across a water body (e.g. river channel, reservoir, or power canal). The downstream terminus of the wall is generally located nearby to a fish bypass structure. If guidance is successful, the fish will avoid entrainment in a dangerous intake structure (i.e. turbine intakes) while passing from the headpond to the tailwater of a hydroelectric facility through a safer passage route (i.e. the bypass). The goal of this study is to determine the combination of guide wall design parameters that will most likely increase the chance of surface-oriented fish being successfully guided to the bypass. To evaluate the flow field immediately upstream of a guide wall, a parameterized computational fluid dynamics model of an idealized power canal was constructed in © ANSYS Fluent v 14.5 (ANSYS Inc., 2012). The design parameters investigated were the angle and depth of the guide wall and the average approach velocity in the power canal. Results call attention to the importance of the downward to sweeping flow ratio and demonstrate how a change in guide wall depth and angle can affect this important hydraulic cue to out-migrating fish. The key findings indicate that a guide wall set at a small angle (15° is the minimum in this study) and deep enough such that sweeping flow dominant conditions prevail within the expected vertical distribution of fish approaching the structure will produce hydraulic conditions that are more likely to result in effective passage.

  11. A study of hydrogen isotopes fuel control by wall effect in magnetic fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Motevalli, S.M., E-mail: motavali@umz.ac.ir; Safari, M.

    2016-11-15

    Highlights: • A particle balance model for the main plasma and wall inventory in magnetic fusion device has been represented. • The dependence of incident particles energy on the wall has been considered in 10–300 eV for the sputtering yield and recycling coefficient. • The effect of fueling methods on plasma density behavior has been studied. - Abstract: Determination of plasma density behavior in magnetic confinement system needs to study the plasma materials interaction in the facing components such as first wall, limiter and divertor. Recycling of hydrogen isotope is an effective parameter in plasma density rate and plasma fueling. Recycling coefficient over the long pulse operation, gets to the unity, so it has a significant effect on steady state in magnetic fusion devices. Typically, sputtered carbon atoms from the plasma facing components form hydrocarbons and they redeposit on the wall. In this case little rate of hydrogen loss occurs. In present work a zero dimensional particle equilibrium model has been represented to determine particles density rate in main plasma and wall inventory under recycling effect and codeposition of hydrogen in case of continues and discontinues fueling methods and effective parameters on the main plasma decay has been studied.

  12. Study of Individual Characteristic Abdominal Wall Thickness Based on Magnetic Anchored Surgical Instruments

    Directory of Open Access Journals (Sweden)

    Ding-Hui Dong

    2015-01-01

    Full Text Available Background: Magnetic anchored surgical instruments (MASI, relying on magnetic force, can break through the limitations of the single port approach in dexterity. Individual characteristic abdominal wall thickness (ICAWT deeply influences magnetic force that determines the safety of MASI. The purpose of this study was to research the abdominal wall characteristics in MASI applied environment to find ICAWT, and then construct an artful method to predict ICAWT, resulting in better safety and feasibility for MASI. Methods: For MASI, ICAWT is referred to the thickness of thickest point in the applied environment. We determined ICAWT through finding the thickest point in computed tomography scans. We also investigated the traits of abdominal wall thickness to discover the factor that can be used to predict ICAWT. Results: Abdominal wall at C point in the middle third lumbar vertebra plane (L3 is the thickest during chosen points. Fat layer thickness plays a more important role in abdominal wall thickness than muscle layer thickness. "BMI-ICAWT" curve was obtained based on abdominal wall thickness of C point in L3 plane, and the expression was as follow: f(x = P1 × x 2 + P2 × x + P3, where P1 = 0.03916 (0.01776, 0.06056, P2 = 1.098 (0.03197, 2.164, P3 = −18.52 (−31.64, −5.412, R-square: 0.99. Conclusions: Abdominal wall thickness of C point at L3 could be regarded as ICAWT. BMI could be a reliable predictor of ICAWT. In the light of "BMI-ICAWT" curve, we may conveniently predict ICAWT by BMI, resulting a better safety and feasibility for MASI.

  13. Study of the Relap5/mod3.2 wall heat flux partitioning model

    International Nuclear Information System (INIS)

    Hari, S.; Hassan, Y.A.

    2001-01-01

    The performance of the subcooled boiling model adapted in RELAP5/MOD3.2 computer code has been assessed in detail for low-pressure conditions and it has been found that the void fraction profile is under-predicted. In general, any subcooled boiling model is composed of individual sub-models that account for the different physical mechanism that govern the overall process, as the wall vapor generation, interfacial shear and condensation etc. The wall heat flux partitioning model is one of the important sub-models that is a constituent of any subcooled boiling model. The function of this model is to apportion the wall heat flux to the different components (as the single/two phase fluid or bubble), as the case may be, in a two-phase flow-boiling scenario adjacent to a heated wall. The ''pumping factor'' approach is generally followed by most of the wall heat flux partitioning models, for partitioning the wall heat flux. In this work, the wall heat flux partitioning model of RELAP5/MOD3.2 computer code is studied; in particular, the ''pumping factor'' formulation in the present code version is assessed for its performance under low-pressure conditions. In addition, three different ''pumping factor'' formulations available in the literature have been introduced into the RELAP5/MOD3.2 code. Simulations of two low-pressure subcooled flow boiling experiments were performed with the refined code versions to determine the appropriate pumping factor to be used under these conditions. (author)

  14. Modelling large motion events in fMRI studies of patients with epilepsy

    DEFF Research Database (Denmark)

    Lemieux, Louis; Salek-Haddadi, Afraim; Lund, Torben E

    2007-01-01

    -positive activation. Head motion can lead to severe image degradation and result in false-positive activation and is usually worse in patients than in healthy subjects. We performed general linear model fMRI data analysis on simultaneous EEG-fMRI data acquired in 34 cases with focal epilepsy. Signal changes...... associated with large inter-scan motion events (head jerks) were modelled using modified design matrices that include 'scan nulling' regressors. We evaluated the efficacy of this approach by mapping the proportion of the brain for which F-tests across the additional regressors were significant. In 95......% of cases, there was a significant effect of motion in 50% of the brain or greater; for the scan nulling effect, the proportion was 36%; this effect was predominantly in the neocortex. We conclude that careful consideration of the motion-related effects in fMRI studies of patients with epilepsy is essential...

  15. Study of imploding liner-electrode wall interaction

    Energy Technology Data Exchange (ETDEWEB)

    Chernyshev, V K; Zharinov, E I; Mokhov, V N [All-Russian Scientific Research Institute of Experimental Physics, Sarov (Russian Federation)

    1997-12-31

    Acceleration of solid aluminium liners and their interaction with electrodes is studied experimentally. One of the main goal of the experiments is to find the method of improving the contact between the liner and the electrode during the acceleration process. Two independent liners connected in series in one discharge circuit are used. This arrangement makes it possible to record two different liner positions simultaneously at one discharge current. As an energy source, a helical explosive magnetic generator of the length of 0.7 m and 100 mm in diameter is used. The shape of liners at various stages of acceleration is recorded by using a flash radiographic facility. The measured liner flight velocity and the compression radius are compared with the results of MHD model calculations. (J.U.). 21 figs., 7 refs.

  16. Realization of a Desktop Flight Simulation System for Motion-Cueing Studies

    Directory of Open Access Journals (Sweden)

    Berkay Volkaner

    2016-05-01

    Full Text Available Parallel robotic mechanisms are generally used in flight simulators with a motion-cueing algorithm to create an unlimited motion feeling of a simulated medium in a bounded workspace of the simulator. A major problem in flight simulators is that the simulation has an unbounded space and the manipulator has a limited one. Using a washout filter in the motion-cueing algorithm overcomes this. In this study, a low-cost six degrees of freedom (DoF desktop parallel manipulator is used to test a classical motion-cueing algorithm; the algorithm's functionality is confirmed with a Simulink real-time environment. Translational accelerations and angular velocities of the simulated medium obtained from FlightGear flight simulation software are processed through a generated washout filter algorithm and the simulated medium's motion information is transmitted to the desktop parallel robotic mechanism as a set point for each leg. The major issues of this paper are designing a desktop simulation system, controlling the parallel manipulator, communicating between the flight simulation and the platform, designing a motion-cueing algorithm and determining the parameters of the washout filters.

  17. MR-assisted PET Motion Correction for eurological Studies in an Integrated MR-PET Scanner

    Science.gov (United States)

    Catana, Ciprian; Benner, Thomas; van der Kouwe, Andre; Byars, Larry; Hamm, Michael; Chonde, Daniel B.; Michel, Christian J.; El Fakhri, Georges; Schmand, Matthias; Sorensen, A. Gregory

    2011-01-01

    Head motion is difficult to avoid in long PET studies, degrading the image quality and offsetting the benefit of using a high-resolution scanner. As a potential solution in an integrated MR-PET scanner, the simultaneously acquired MR data can be used for motion tracking. In this work, a novel data processing and rigid-body motion correction (MC) algorithm for the MR-compatible BrainPET prototype scanner is described and proof-of-principle phantom and human studies are presented. Methods To account for motion, the PET prompts and randoms coincidences as well as the sensitivity data are processed in the line or response (LOR) space according to the MR-derived motion estimates. After sinogram space rebinning, the corrected data are summed and the motion corrected PET volume is reconstructed from these sinograms and the attenuation and scatter sinograms in the reference position. The accuracy of the MC algorithm was first tested using a Hoffman phantom. Next, human volunteer studies were performed and motion estimates were obtained using two high temporal resolution MR-based motion tracking techniques. Results After accounting for the physical mismatch between the two scanners, perfectly co-registered MR and PET volumes are reproducibly obtained. The MR output gates inserted in to the PET list-mode allow the temporal correlation of the two data sets within 0.2 s. The Hoffman phantom volume reconstructed processing the PET data in the LOR space was similar to the one obtained processing the data using the standard methods and applying the MC in the image space, demonstrating the quantitative accuracy of the novel MC algorithm. In human volunteer studies, motion estimates were obtained from echo planar imaging and cloverleaf navigator sequences every 3 seconds and 20 ms, respectively. Substantially improved PET images with excellent delineation of specific brain structures were obtained after applying the MC using these MR-based estimates. Conclusion A novel MR-based MC

  18. Dynamics of plane-symmetric thin walls in general relativity

    International Nuclear Information System (INIS)

    Wang, A.

    1992-01-01

    Plane walls (including plane domain walls) without reflection symmetry are studied in the framework of Einstein's general relativity. Using the distribution theory, all the Einstein field equations and Bianchi identities are split into two groups: one holding in the regions outside of the wall and the other holding at the wall. The Einstein field equations at the wall are found to take a very simple form, and given explicitly in terms of the discontinuities of the metric coefficients and their derivatives. The Bianchi identities at the wall are also given explicitly. Using the latter, the interaction of a plane wall with gravitational waves and some specific matter fields is studied. In particular, it is found that, when a gravitational plane wave passes through a wall, if the wall has no reflection symmetry, the phenomena, such as reflection, stimulation, or absorption, in general, occur. It is also found that, unlike for gravitational waves, a massless scalar wave or an electromagnetic wave continuously passes through a wall without any reflection. The repulsion and attraction of a plane wall are also studied. It is found that the acceleration of an observer who is at rest relative to the wall usually consists of three parts: one is due to the force produced by the wall, the second is due to the force produced by the space-time curvature, which is zero if the wall has reflection symmetry, and the last is due to the accelerated motion of the wall. As a result, a repulsive (attractive) plane wall may not be repulsive (attractive) at all. Finally, the collision and interaction among the walls are studied

  19. Numerical case studies of vertical wall fire protection using water spray

    Directory of Open Access Journals (Sweden)

    L.M. Zhao

    2014-11-01

    Full Text Available Studies of vertical wall fire protection are evaluated with numerical method. Typical fire cases such as heated dry wall and upward flame spread have been validated. Results predicted by simulations are found to agree with experiment results. The combustion behavior and flame development of vertical polymethylmethacrylate slabs with different water flow rates are explored and discussed. Water spray is found to be capable of strengthening the fire resistance of combustible even under high heat flux radiation. Provided result and data are expected to provide reference for fire protection methods design and development of modern buildings.

  20. "Dismantling the Wall, One Brick at a Time": Overcoming Barriers to Parochialism in Social Studies Classrooms.

    Science.gov (United States)

    Foster, Stuart J.; Hoge, John D.

    2000-01-01

    Discusses the classroom practice of Geri Collins who is a veteran eighth grade social studies teacher. Explains how, through her teaching, she attempts to break down the wall her students have around them. Highlights the four characteristics that make her teaching an example of wise practice. (CMK)

  1. Experimental study of a turbulent boundary layer on a rough wall

    International Nuclear Information System (INIS)

    Trijoulet, Alexandre

    1999-01-01

    This research thesis reports the definition and results of an experimental study of a two-dimensional incompressible turbulent boundary layer on a rough wall in presence of pressure gradients. This study is motivated by problems met on pump blades by EDF. The author first reports a detailed bibliographical study on the current knowledge regarding the structure of turbulent boundary layers on smooth and rough walls, while more particularly focusing on the notion of wall law. Based on an analysis of Navier-Stokes equations, the author discusses the elaboration of a local partial similitude between two-dimensional flows obtained in wind tunnel and three-dimensional flows in presence of a uniform rotation for flows present within pumps. Thus, the author reproduces the main characteristics of boundary layers on pump walls in a simplified experimental arrangement in which detailed and reliable measurements are possible. In the next part, the author addresses the case of helical-centrifugal pumps. Based on calculation performed by other authors, the above-mentioned similitude parameters are assessed. Results are used to define experimental arrangements suitable for this study. An experimental installation is then presented, as well as the data processing scheme. Experimental results are presented and discussed for flows without pressure gradient, slowed down or accelerated on different surface conditions [fr

  2. Feasibility Study to Reduce Thermal Resistance of Finned Containment Wall in Simplified OPR1000

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Hwi; Kang, Hie Chan [Kunsan National University, Gunsan (Korea, Republic of); Noh, Hyung Gyun [Pohang University, Pohang (Korea, Republic of)

    2016-05-15

    This concept is securing of cooling capability by using finned containment itself, it could be another alternative for achieving decompression of containment as heat sink. The objective of this study is a feasibility test to estimate the heat transfer performance from the finned containment wall in case of OPR1000. The commercial code, ANSYS CFX 16 was used in this work. The number of grids is about 1.8 million. Therefore, 250mm rebar affects more considerable than that of 50mm to the temperature distribution. For this reasons, temperature distribution of z-axis direction was showed significant changes in (c). The heat transfer in three types of containment was 267.6W, 265.2W and 307.8W, respectively. The Type B case increased up to 15% of heat transfer than the baseline containment building. Three different types of containment wall were tested by numerical simulation to understand the cooling performance of finned containment wall. We can conclude as follows: For the finned containment wall type A that fins are installed inside and outside with the same rebar configuration of conventional containment building, the heat transfer is almost the same as conventional containment wall. The finned containment wall type B that volume fraction of rebar is increased transfer the heat 15% more compared with conventional one. The cross-sectional area or volume fraction of the rebar to attach fin is important to enhance the heat transfer. The fin efficiency of the fin is very low as 3.1% in the present cases.

  3. The effect of dynamic femoroacetabular impingement on pubic symphysis motion: a cadaveric study.

    Science.gov (United States)

    Birmingham, Patrick M; Kelly, Bryan T; Jacobs, Robert; McGrady, Linda; Wang, Mei

    2012-05-01

    A link between femoroacetabular impingement and athletic pubalgia has been reported clinically. One proposed origin of athletic pubalgia is secondary to repetitive loading of the pubic symphysis, leading to instability and parasymphyseal tendon and ligament injury. Hypothesis/ The purpose of this study was to investigate the effect of simulated femoral-based femoroacetabular impingement on rotational motion at the pubic symphysis. The authors hypothesize that the presence of a cam lesion leads to increased relative symphyseal motion. Controlled laboratory study. Twelve hips from 6 fresh-frozen human cadaveric pelvises were used to simulate cam-type femoroacetabular impingement. The hips were held in a custom jig and maximally internally rotated at 90° of flexion and neutral adduction. Three-dimensional motion of the pubic symphysis was measured by a motion-tracking system for 2 states: native and simulated cam. Load-displacement plots were generated between the internal rotational torque applied to the hip and the responding motion in 3 anatomic planes of the pubic symphysis. As the hip was internally rotated, the motion at the pubic symphysis increased proportionally with the degrees of the rotation as well as the applied torque measured at the distal femur for both states. The primary rotation of the symphysis was in the transverse plane and on average accounted for more than 60% of the total rotation. This primary motion caused the anterior aspect of the symphyseal joint to open or widen, whereas the posterior aspect narrowed. At the torque level of 18.0 N·m, the mean transverse rotation in degrees was 0.89° ± 0.35° for the native state and 1.20° ± 0.41° for cam state. The difference between cam and the native groups was statistically significant (P pubalgia.

  4. Experimental, numerical, and analytical studies on the seismic response of steel-plate concrete (SC) composite shear walls

    Science.gov (United States)

    Epackachi, Siamak

    The seismic performance of rectangular steel-plate concrete (SC) composite shear walls is assessed for application to buildings and mission-critical infrastructure. The SC walls considered in this study were composed of two steel faceplates and infill concrete. The steel faceplates were connected together and to the infill concrete using tie rods and headed studs, respectively. The research focused on the in-plane behavior of flexure- and flexure-shear-critical SC walls. An experimental program was executed in the NEES laboratory at the University at Buffalo and was followed by numerical and analytical studies. In the experimental program, four large-size specimens were tested under displacement-controlled cyclic loading. The design variables considered in the testing program included wall thickness, reinforcement ratio, and slenderness ratio. The aspect ratio (height-to-length) of the four walls was 1.0. Each SC wall was installed on top of a re-usable foundation block. A bolted baseplate to RC foundation connection was used for all four walls. The walls were identified to be flexure- and flexure-shear critical. The progression of damage in the four walls was identical, namely, cracking and crushing of the infill concrete at the toes of the walls, outward buckling and yielding of the steel faceplates near the base of the wall, and tearing of the faceplates at their junctions with the baseplate. A robust finite element model was developed in LS-DYNA for nonlinear cyclic analysis of the flexure- and flexure-shear-critical SC walls. The DYNA model was validated using the results of the cyclic tests of the four SC walls. The validated and benchmarked models were then used to conduct a parametric study, which investigated the effects of wall aspect ratio, reinforcement ratio, wall thickness, and uniaxial concrete compressive strength on the in-plane response of SC walls. Simplified analytical models, suitable for preliminary analysis and design of SC walls, were

  5. Sacroiliac Joint Fusion Minimally Affects Adjacent Lumbar Segment Motion: A Finite Element Study.

    Science.gov (United States)

    Lindsey, Derek P; Kiapour, Ali; Yerby, Scott A; Goel, Vijay K

    2015-01-01

    Adjacent segment disease is a recognized consequence of fusion in the spinal column. Fusion of the sacroiliac joint is an effective method of pain reduction. Although effective, the consequences of sacroiliac joint fusion and the potential for adjacent segment disease for the adjacent lumbar spinal levels is unknown. The objective of this study was to quantify the change in range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments due to sacroiliac joint fusion and compare these changes to previous literature to assess the potential for adjacent segment disease in the lumbar spine. An experimentally validated finite element model of the lumbar spine and pelvis was used to simulate a fusion of the sacroiliac joint using three laterally placed triangular implants (iFuse Implant System, SI-BONE, Inc., San Jose, CA). The range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments were calculated using a hybrid loading protocol and compared with the intact range of motion in flexion, extension, lateral bending, and axial rotation. The range of motions of the treated sacroiliac joints were reduced in flexion, extension, lateral bending, and axial rotation, by 56.6%, 59.5%, 27.8%, and 53.3%, respectively when compared with the intact condition. The stiffening of the sacroiliac joint resulted in increases at the adjacent lumbar motion segment (L5-S1) for flexion, extension, lateral bending, and axial rotation, of 3.0%, 3.7%, 1.1%, and 4.6%, respectively. Fusion of the sacroiliac joint resulted in substantial (> 50%) reductions in flexion, extension, and axial rotation of the sacroiliac joint with minimal (sacroiliac joint fusion, the long-term clinical results remain to be investigated.

  6. Cervical isometric strength and range of motion of elite rugby union players: a cohort study.

    Science.gov (United States)

    Hamilton, David F; Gatherer, Don

    2014-01-01

    Head and neck injury is relatively common in Rugby Union. Despite this, strength and range-of-motion characteristics of the cervical spine are poorly characterised. The aim of this study was to provide data on the strength and range-of-motion of the cervical spine of professional rugby players to guide clinical rehabilitation. A cohort study was performed evaluating 27 players from a single UK professional rugby club. Cervical isometric strength and range-of-motion were assessed in 3 planes of reference. Anthropometric data was collected and multivariate regression modelling performed with a view to predicting cervical isometric strength. Largest forces were generated in extension, with broadly equal isometric side flexion forces at around 90% of extension values. The forwards generated significantly more force than the backline in all parameters bar flexion. The forwards had substantially reduced cervical range-of-motion and larger body mass, with differences observed in height, weight, neck circumference and chest circumference (p isometric extension (adjusted R(2) = 30.34). Rehabilitative training programs aim to restore individuals to pre-injury status. This work provides reference ranges for the strength and range of motion of the cervical spine of current elite level rugby players.

  7. Benchmark study of ionization potentials and electron affinities of armchair single-walled carbon nanotubes using density functional theory

    Science.gov (United States)

    Zhou, Bin; Hu, Zhubin; Jiang, Yanrong; He, Xiao; Sun, Zhenrong; Sun, Haitao

    2018-05-01

    The intrinsic parameters of carbon nanotubes (CNTs) such as ionization potential (IP) and electron affinity (EA) are closely related to their unique properties and associated applications. In this work, we demonstrated the success of optimal tuning method based on range-separated (RS) density functionals for both accurate and efficient prediction of vertical IPs and electron affinities (EAs) of a series of armchair single-walled carbon nanotubes C20n H20 (n  =  2–6) compared to the high-level IP/EA equation-of-motion coupled-cluster method with single and double substitutions (IP/EA-EOM-CCSD). Notably, the resulting frontier orbital energies (–ε HOMO and –ε LUMO) from the tuning method exhibit an excellent approximation to the corresponding IPs and EAs, that significantly outperform other conventional density functionals. In addition, it is suggested that the RS density functionals that possess both a fixed amount of exact exchange in the short-range and a correct long-range asymptotic behavior are suitable for calculating electronic structures of finite-sized CNTs. Next the performance of density functionals for description of various molecular properties such as chemical potential, hardness and electrophilicity are assessed as a function of tube length. Thanks to the efficiency and accuracy of this tuning method, the related behaviors of much longer armchair single-walled CNTs until C200H20 were studied. Lastly, the present work is proved to provide an efficient theoretical tool for future materials design and reliable characterization of other interesting properties of CNT-based systems.

  8. The Use of Wearable Inertial Motion Sensors in Human Lower Limb Biomechanics Studies: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Yue-Yan Chan

    2010-12-01

    Full Text Available Wearable motion sensors consisting of accelerometers, gyroscopes and magnetic sensors are readily available nowadays. The small size and low production costs of motion sensors make them a very good tool for human motions analysis. However, data processing and accuracy of the collected data are important issues for research purposes. In this paper, we aim to review the literature related to usage of inertial sensors in human lower limb biomechanics studies. A systematic search was done in the following search engines: ISI Web of Knowledge, Medline, SportDiscus and IEEE Xplore. Thirty nine full papers and conference abstracts with related topics were included in this review. The type of sensor involved, data collection methods, study design, validation methods and its applications were reviewed.

  9. The use of wearable inertial motion sensors in human lower limb biomechanics studies: a systematic review.

    Science.gov (United States)

    Fong, Daniel Tik-Pui; Chan, Yue-Yan

    2010-01-01

    Wearable motion sensors consisting of accelerometers, gyroscopes and magnetic sensors are readily available nowadays. The small size and low production costs of motion sensors make them a very good tool for human motions analysis. However, data processing and accuracy of the collected data are important issues for research purposes. In this paper, we aim to review the literature related to usage of inertial sensors in human lower limb biomechanics studies. A systematic search was done in the following search engines: ISI Web of Knowledge, Medline, SportDiscus and IEEE Xplore. Thirty nine full papers and conference abstracts with related topics were included in this review. The type of sensor involved, data collection methods, study design, validation methods and its applications were reviewed.

  10. Development of visual motion perception for prospective control: Brain and behavioural studies in infants

    Directory of Open Access Journals (Sweden)

    Seth B. Agyei

    2016-02-01

    Full Text Available During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioural and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioural data when studying the neural correlates of prospective control.

  11. MR-assisted PET motion correction in simultaneous PET/MRI studies of dementia subjects.

    Science.gov (United States)

    Chen, Kevin T; Salcedo, Stephanie; Chonde, Daniel B; Izquierdo-Garcia, David; Levine, Michael A; Price, Julie C; Dickerson, Bradford C; Catana, Ciprian

    2018-03-08

    Subject motion in positron emission tomography (PET) studies leads to image blurring and artifacts; simultaneously acquired magnetic resonance imaging (MRI) data provides a means for motion correction (MC) in integrated PET/MRI scanners. To assess the effect of realistic head motion and MR-based MC on static [ 18 F]-fluorodeoxyglucose (FDG) PET images in dementia patients. Observational study. Thirty dementia subjects were recruited. 3T hybrid PET/MR scanner where EPI-based and T 1 -weighted sequences were acquired simultaneously with the PET data. Head motion parameters estimated from high temporal resolution MR volumes were used for PET MC. The MR-based MC method was compared to PET frame-based MC methods in which motion parameters were estimated by coregistering 5-minute frames before and after accounting for the attenuation-emission mismatch. The relative changes in standardized uptake value ratios (SUVRs) between the PET volumes processed with the various MC methods, without MC, and the PET volumes with simulated motion were compared in relevant brain regions. The absolute value of the regional SUVR relative change was assessed with pairwise paired t-tests testing at the P = 0.05 level, comparing the values obtained through different MR-based MC processing methods as well as across different motion groups. The intraregion voxelwise variability of regional SUVRs obtained through different MR-based MC processing methods was also assessed with pairwise paired t-tests testing at the P = 0.05 level. MC had a greater impact on PET data quantification in subjects with larger amplitude motion (higher than 18% in the medial orbitofrontal cortex) and greater changes were generally observed for the MR-based MC method compared to the frame-based methods. Furthermore, a mean relative change of ∼4% was observed after MC even at the group level, suggesting the importance of routinely applying this correction. The intraregion voxelwise variability of regional SUVRs

  12. TH-EF-BRB-08: Robotic Motion Compensation for Radiation Therapy: A 6DOF Phantom Study

    Energy Technology Data Exchange (ETDEWEB)

    Belcher, AH; Liu, X; Wiersma, R [The University of Chicago, Chicago, IL (United States)

    2016-06-15

    Purpose: The high accuracy of frame-based stereotactic radiosurgery (SRS), which uses a rigid frame fixed to the patient’s skull, is offset by potential drawbacks of poor patient compliance and clinical workflow restrictions. Recent research into frameless SRS has so far resulted in reduced accuracy. In this study, we investigate the use of a novel 6 degree-of-freedom (6DOF) robotic head motion cancellation system that continuously detects and compensates for patient head motions during a SRS delivery. This approach has the potential to reduce invasiveness while still achieving accuracies better or equal to traditional frame-based SRS. Methods: A 6DOF parallel kinematics robotics stage was constructed, and controlled using an inverse kinematics-based motion compensation algorithm. A 6DOF stereoscopic infrared (IR) marker tracking system was used to monitor real-time motions at sub-millimeter and sub-degree levels. A novel 6DOF calibration technique was first applied to properly orient the camera coordinate frame to match that of the LINAC and robotic control frames. Simulated head motions were measured by the system, and the robotic stage responded to these 6DOF motions automatically, returning the reflective marker coordinate frame to its original position. Results: After the motions were introduced to the system in the phantom-based study, the robotic stage automatically and rapidly returned the phantom to LINAC isocenter. When errors exceeded the compensation lower threshold of 0.25 mm or 0.25 degrees, the system registered the 6DOF error and generated a cancellation trajectory. The system responded in less than 0.5 seconds and returned all axes to less than 0.1 mm and 0.1 degree after the 6DOF compensation was performed. Conclusion: The 6DOF real-time motion cancellation system was found to be effective at compensating for translational and rotational motions to current SRS requirements. This system can improve frameless SRS by automatically returning

  13. TH-EF-BRB-08: Robotic Motion Compensation for Radiation Therapy: A 6DOF Phantom Study

    International Nuclear Information System (INIS)

    Belcher, AH; Liu, X; Wiersma, R

    2016-01-01

    Purpose: The high accuracy of frame-based stereotactic radiosurgery (SRS), which uses a rigid frame fixed to the patient’s skull, is offset by potential drawbacks of poor patient compliance and clinical workflow restrictions. Recent research into frameless SRS has so far resulted in reduced accuracy. In this study, we investigate the use of a novel 6 degree-of-freedom (6DOF) robotic head motion cancellation system that continuously detects and compensates for patient head motions during a SRS delivery. This approach has the potential to reduce invasiveness while still achieving accuracies better or equal to traditional frame-based SRS. Methods: A 6DOF parallel kinematics robotics stage was constructed, and controlled using an inverse kinematics-based motion compensation algorithm. A 6DOF stereoscopic infrared (IR) marker tracking system was used to monitor real-time motions at sub-millimeter and sub-degree levels. A novel 6DOF calibration technique was first applied to properly orient the camera coordinate frame to match that of the LINAC and robotic control frames. Simulated head motions were measured by the system, and the robotic stage responded to these 6DOF motions automatically, returning the reflective marker coordinate frame to its original position. Results: After the motions were introduced to the system in the phantom-based study, the robotic stage automatically and rapidly returned the phantom to LINAC isocenter. When errors exceeded the compensation lower threshold of 0.25 mm or 0.25 degrees, the system registered the 6DOF error and generated a cancellation trajectory. The system responded in less than 0.5 seconds and returned all axes to less than 0.1 mm and 0.1 degree after the 6DOF compensation was performed. Conclusion: The 6DOF real-time motion cancellation system was found to be effective at compensating for translational and rotational motions to current SRS requirements. This system can improve frameless SRS by automatically returning

  14. Influence of roof motion in LMFBR containment loading studies

    International Nuclear Information System (INIS)

    Potter, R.; Lancefield, M.J.; Sidoli, J.E.A.; Broadhouse, B.J.; Green, R.S.

    1982-01-01

    Following an HCDA the reactor roof may be threatened by coolant impact. Recent trends in CDFR roof design suggest that roof movement during the impact process may reduce the roof loading as a result of the fluid-structure interaction. The paper describes analytic studies of the phenomena, extensions to the SEURBNUK containment code to the roof flexibility and fluid-structure coupling, and results of experiments which confirm the reduced impulse and provide validation of the mathematical modelling

  15. Flash-x-radiography for fuel motion studies

    International Nuclear Information System (INIS)

    Choate, L.M.; Halbleib, J.A. Sr.; Posey, L.D.

    1976-01-01

    The paper is primarily intended to be a status report on recent activities in the Flash X-ray Radiography/Cinematography area. Studies in the area of source definition as well as associated experimental limitations are discussed. The implications of machine current upon precision uncertainty in measurements of changes in areal density are presented. The radiographic techniques presently being evaluated are discussed. Performance estimates representative of this type of diagnostic tool are presented. Comparison with other results is made

  16. Study of Local and Distortional Stability of Thin-Walled Structures

    Directory of Open Access Journals (Sweden)

    Imene Mahi

    2018-01-01

    Full Text Available Thin-walled structures have an increasingly large and growing field of application in the engineering sector, the goal behind using this type of structure is efficiency in terms of resistance and cost, however the stability of its components (the thin walls remains the first aspect of the behavior, and a primordial factor in the design process. The hot rolled sections are known by a consequent post-buckling reserve, cold-formed steel sections which are thin-walled elements also benefit, in this case, it seems essential to take into account the favorable effects of this reserve in to the verification procedure of the resistance with respect to the three modes of failures of this type of structure. The design method that takes into account this reserve of resistance is inevitably the effective width method. The direct strength method has been developed to improve the speed and efficiency of the design of thin-walled profiles. The latter mainly uses the buckling loads (for Local, Distortional and Global mode obtained from a numerical analysis and the resistance curves calibrated experimentally to predict the ultimate load of the profile. Among those, the behavior of a set of Cshaped profiles (highly industrialized is studied, this type of section is assumed to be very prone to modes of local and distortional instability. The outcome of this investigation revealed very relevant conclusions both scientifically and practically.

  17. Normal anatomy of the anal wall and perianal spaces: An EUS, MRI and cadaveric correlative study

    International Nuclear Information System (INIS)

    Chung, Soo Young; Ryu, Sie Tae; Park, Ki Soon; Lee, Yul; Bae, Sang Hoon; Kang, Heung Sik

    1994-01-01

    To understand the normal endosonographic anatomy of the perianal spaces, and to evaluate the diagnostic efficacy and limitation of endorectal sonography(EUS), correlative study with MRI, cadaveric sectional image and cadaveric MRI were performed. EUS images of the normal 6 perianal spaces (pelvirectal, ischiorectal, intersphincteric, subcutaneous, central, submucous space) which were bounded by internal and external anal sphincters, rectal wall and levator ani muscle were correlated with MRI in 10 normal persons, cadaveric sectional images and cadaveric MRI in 2 cadavers. Pelvirectal space located superior to levator ani muscle could be demonstrable only on anterior wall scan but could not be visualized on lateral or posterior wall scan on EUS. Five perianal spaces located inferior to levator ani muscle were well seen on anterior, lateral, and posterior wall EUS. MRI was superior to EUS in the evaluation of pelvirectal and ischiorectal spaces but equal or inferior to EUS in the evaluation of intersphincteric, subcutaneous, central and submucous spaces. EUS was valuable in the evaluation of perianal spaces inferior to levator ani muscle but was limited in the evaluation of perianal spaces superior to levator ani muscle

  18. Leveraging respiratory organ motion for non-invasive tumor treatment devices: a feasibility study

    Science.gov (United States)

    Möri, Nadia; Jud, Christoph; Salomir, Rares; Cattin, Philippe C.

    2016-06-01

    In noninvasive abdominal tumor treatment, research has focused on minimizing organ motion either by gating, breath holding or tracking of the target. The paradigm shift proposed in this study takes advantage of the respiratory organ motion to passively scan the tumor. In the proposed self-scanning method, the focal point of the HIFU device is held fixed for a given time, while it passively scans the tumor due to breathing motion. The aim of this paper is to present a treatment planning method for such a system and show by simulation its feasibility. The presented planning method minimizes treatment time and ensures complete tumor ablation under free-breathing. We simulated our method on realistic motion patterns from a patient specific statistical respiratory model. With our method, we achieved a shorter treatment time than with the gold-standard motion-compensation approach. The main advantage of the proposed method is that electrically steering of the focal spot is no longer needed. As a consequence, it is much easier to find an optimal solution for both avoiding near field heating and covering the whole tumor. However, the reduced complexity on the beam forming comes at the price of an increased complexity on the planning side as well as a reduced efficiency in the energy distribution. Although we simulate the approach on HIFU, the idea of self-scanning passes over to other tumor treatment modalities such as proton therapy or classical radiation therapy.

  19. Earthquake strong ground motion studies at the Idaho National Engineering Laboratory

    International Nuclear Information System (INIS)

    Wong, Ivan; Silva, W.; Darragh, R.; Stark, C.; Wright, D.; Jackson, S.; Carpenter, G.; Smith, R.; Anderson, D.; Gilbert, H.; Scott, D.

    1989-01-01

    Site-specific strong earthquake ground motions have been estimated for the Idaho National Engineering Laboratory assuming that an event similar to the 1983 M s 7.3 Borah Peak earthquake occurs at epicentral distances of 10 to 28 km. The strong ground motion parameters have been estimated based on a methodology incorporating the Band-Limited-White-Noise ground motion model coupled with Random Vibration Theory. A 16-station seismic attenuation and site response survey utilizing three-component portable digital seismographs was also performed for a five-month period in 1989. Based on the recordings of regional earthquakes, the effects of seismic attenuation in the shallow crust and along the propagation path and local site response were evaluated. This data combined with a detailed geologic profile developed for each site based principally on borehole data, was used in the estimation of the strong ground motion parameters. The preliminary peak horizontal ground accelerations for individual sites range from approximately 0.15 to 0.35 g. Based on the authors analysis, the thick sedimentary interbeds (greater than 20 m) in the basalt section attenuate ground motions as speculated upon in a number of previous studies

  20. Turbulence characterization by studying laser beam wandering in a differential tracking motion setup

    Science.gov (United States)

    Pérez, Darío G.; Zunino, Luciano; Gulich, Damián; Funes, Gustavo; Garavaglia, Mario

    2009-09-01

    The Differential Image Motion Monitor (DIMM) is a standard and widely used instrument for astronomical seeing measurements. The seeing values are estimated from the variance of the differential image motion over two equal small pupils some distance apart. The twin pupils are usually cut in a mask on the entrance pupil of the telescope. As a differential method, it has the advantage of being immune to tracking errors, eliminating erratic motion of the telescope. The Differential Laser Tracking Motion (DLTM) is introduced here inspired by the same idea. Two identical laser beams are propagated through a path of air in turbulent motion, at the end of it their wander is registered by two position sensitive detectors-at a count of 800 samples per second. Time series generated from the difference of the pair of centroid laser beam coordinates is then analyzed using the multifractal detrended fluctuation analysis. Measurements were performed at the laboratory with synthetic turbulence: changing the relative separation of the beams for different turbulent regimes. The dependence, with respect to these parameters, and the robustness of our estimators is compared with the non-differential method. This method is an improvement with respect to previous approaches that study the beam wandering.

  1. A study of particle motion in rotary dryer

    Directory of Open Access Journals (Sweden)

    M. H. Lisboa

    2007-09-01

    Full Text Available The purpose of this work was to study the performance of a rotary dryer in relation to number of flights. In this work an equationing was proposed to calculate the area used by the solids in two-segment flights of with any angle between the segments. From this area, the flight holdup and the length of fall of the particles were calculated for different angle positions and the results obtained were compared to experimental values. The results show an increase in dryer efficiency with the increase in number of flights up to a limit value, for ideal operational conditions. The experimental data on average residence time were compared to results obtained by calculations using equations proposed in the literature. The equation proposed for predicting flight holdup and length of fall of particles generated very accurate estimations.

  2. Experimental motion behavior of submerged fuel racks

    International Nuclear Information System (INIS)

    Ellingson, F.J.; Wachter, W.; Moscardini, R.L.

    1989-01-01

    The design of submerged nuclear storage racks for light water reactor nuclear fuel has undergone a change from fixed position to a free-standing arrangement. Seismic analysis of the motion of the free-standing racks requires three-dimensional computer modeling that uses past studies of hydrodynamic mass and hydraulic coupling for rigid flat plates. This paper describes the results of experiments that show a reduced value for hydrodynamic mass and coupling forces when flexible elements are involved. To support this work, experiments were run with two full-scale welded box sections submerged in a water tank. The preliminary results indicate reduction in hydrodynamic mass due to box wall flexibility, a lack of impacting of box wall to box wall over the entire frequency range, and large hydrodynamic coupling forces under all test conditions. It is hypothesized that the coupling forces are sufficiently strong to prevent rotational motion of one rack when surrounded by adjacent racks

  3. Neutronic performance optimization study of Indian fusion demo reactor first wall and breeding blanket

    International Nuclear Information System (INIS)

    Swami, H.L.; Danani, C.

    2015-01-01

    In frame of design studies of Indian Nuclear Fusion DEMO Reactor, neutronic performance optimization of first wall and breeding blanket are carried out. The study mainly focuses on tritium breeding ratio (TBR) and power density responses estimation of breeding blanket. Apart from neutronic efficiency of existing breeding blanket concepts for Indian DEMO i.e. lead lithium ceramic breeder and helium cooled solid breeder concept other concepts like helium cooled lead lithium and helium-cooled Li_8PbO_6 with reflector are also explored. The aim of study is to establish a neutronically efficient breeding blanket concept for DEMO. Effect of first wall materials and thickness on breeding blanket neutronic performance is also evaluated. For this study 1 D cylindrical neutronic model of DEMO has been constructed according to the preliminary radial build up of Indian DEMO. The assessment is being done using Monte Carlo based radiation transport code and nuclear cross section data file ENDF/B- VII. (author)

  4. Anatomic factors affecting the use of ultrasound to predict vocal fold motion: A pilot study.

    Science.gov (United States)

    Masood, Maheer M; Huang, Benjamin; Goins, Allie; Hackman, Trevor G

    2018-04-13

    Ultrasonography is a well-established modality for visualization of head and neck anatomy. Using ultrasound to detect vocal fold mobility has been described before, but no study has evaluated factors affecting the exam reliability. The aim of the study is to determine anatomic factors influencing the reliability of ultrasound to detect vocal fold motion. Methods and materials Patients underwent ultrasound evaluation and flexible laryngoscopy to assess vocal fold motion from August 2015 to March 2016. Length, accuracy, and clarity of ultrasound examination were assessed, compared to flexible laryngoscopy. For patients with prior neck CT scan imaging, laryngeal anatomy was independently assessed by a blinded neuroradiologist. A total of 23 patients, 21 with bilateral vocal fold motion and two with unilateral paralysis, were enrolled. Vocal folds were visible in 19 patients (82%). Eight patients (42%) had good/excellent view and 11 patients (58%) had fair/difficult view. The ultrasound correctly detected absent movement of the vocal fold in the two patients with unilateral paralysis. A total of 19 patients had CT scans, and a linear correlation (r 2  = 0.65) was noted between the anterior thyroid cartilage angle measured on CT and the grade of view on ultrasound. Ultrasound was able to detect vocal fold motion in 82% of randomly screened patients. Ease of detection of vocal fold motion correlated with the anterior thyroid angle. Further studies are warranted to investigate the reproducibility of our results and how this might impact use of ultrasound for detection of vocal fold motion in the operative setting. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Semi-analytical study of the rotational motion stability of artificial satellites using quaternions

    International Nuclear Information System (INIS)

    Dos Santos, Josué C; Zanardi, Maria Cecília; Matos, Nicholas

    2013-01-01

    This study at aims performing the stability analysis of the rotational motion to artificial satellites using quaternions to describe the satellite attitude (orientation on the space). In the system of rotational motion equations, which is composed by four kinematic equations of the quaternions and by the three Euler equations in terms of the rotational spin components. The influence of the gravity gradient and the direct solar radiation pressure torques have been considered. Equilibrium points were obtained through numerical simulations using the softwares Matlab and Octave, which are then analyzed by the Routh-Hurwitz Stability Criterion

  6. Study of the motion of a vertically falling sphere in a viscous fluid

    International Nuclear Information System (INIS)

    Soares, A A; Caramelo, L; Andrade, M A P M

    2012-01-01

    This paper aims at contributing to a better understanding of the motion of spherical particles in viscous fluids. The classical problem of spheres falling through viscous fluids for small Reynolds numbers was solved taking into account the effects of added mass. The analytical solution for the motion of a falling sphere, from the beginning to the end of the fall, was combined with an iterative numerical method to determine the fluid viscosity coefficient, diameter of the sphere and terminal velocity. The proposed solution was validated with experimental literature data. The study presented may also help understanding the fluid-particle interactions from both theoretical and educational standpoints. (paper)

  7. An experimental study of the fluid mechanics associated with porous walls

    Science.gov (United States)

    Ramachandran, N.; Heaman, J.; Smith, A.

    1992-01-01

    The fluid mechanics of air exiting from a porous material is investigated. The experiments are filter rating dependent, as porous walls with filter ratings differing by about three orders of magnitude are studied. The flow behavior is investigated for its spatial and temporal stability. The results from the investigation are related to jet behavior in at least one of the following categories: (1) jet coalescence effects with increasing flow rate; (2) jet field decay with increasing distance from the porous wall; (3) jet field temporal turbulence characteristics; and (4) single jet turbulence characteristics. The measurements show that coalescence effects cause jet development, and this development stage can be traced by measuring the pseudoturbulence (spatial velocity variations) at any flow rate. The pseudoturbulence variation with increasing mass flow reveals an initial increasing trend followed by a leveling trend, both of which are directly proportional to the filter rating. A critical velocity begins this leveling trend and represents the onset of fully developed jetting action in the flow field. A correlation is developed to predict the onset of fully developed jets in the flow emerging from a porous wall. The data further show that the fully developed jet dimensions are independent of the filter rating, thus providing a length scale for this type of flow field (1 mm). Individual jet characteristics provide another unifying trend with similar velocity decay behavior with distance; however, the respective turbulence magnitudes show vast differences between jets from the same sample. Measurements of the flow decay with distance from the porous wall show that the higher spatial frequency components of the jet field dissipate faster than the lower frequency components. Flow turbulence intensity measurements show an out of phase behavior with the velocity field and are generally found to increase as the distance from the wall is increased.

  8. Trochanteric fracture-implant motion during healing - A radiostereometry (RSA) study.

    Science.gov (United States)

    Bojan, Alicja J; Jönsson, Anders; Granhed, Hans; Ekholm, Carl; Kärrholm, Johan

    2018-03-01

    Cut-out complication remains a major unsolved problem in the treatment of trochanteric hip fractures. A better understanding of the three-dimensional fracture-implant motions is needed to enable further development of clinical strategies and countermeasures. The aim of this clinical study was to characterise and quantify three-dimensional motions between the implant and the bone and between the lag screw and nail of the Gamma nail. Radiostereometry Analysis (RSA) analysis was applied in 20 patients with trochanteric hip fractures treated with an intramedullary nail. The following three-dimensional motions were measured postoperatively, at 1 week, 3, 6 and 12 months: translations of the tip of the lag screw in the femoral head, motions of the lag screw in the nail, femoral head motions relative to the nail and nail movements in the femoral shaft. Cranial migration of the tip of the lag screw dominated over the other two translation components in the femoral head. In all fractures the lag screw slid laterally in the nail and the femoral head moved both laterally and inferiorly towards the nail. All femoral heads translated posteriorly relative to the nail, and rotations occurred in both directions with median values close to zero. The nail tended to retrovert in the femoral shaft. Adverse fracture-implant motions were detected in stable trochanteric hip fractures treated with intramedullary nails with high resolution. Therefore, RSA method can be used to evaluate new implant designs and clinical strategies, which aim to reduce cut-out complications. Future RSA studies should aim at more unstable fractures as these are more likely to fail with cut-out. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. CFD simulations to study the effects of wall protrusions on microfluidic mixing

    Science.gov (United States)

    Sarkar, Sourav; Singh, K. K.; Shankar, V.; Shenoy, K. T.

    2015-08-01

    In this study the effects of different types of wall protrusions on microfluidic mixing are studied using computational fluid dynamics (CFD) simulations. Two new protrusions, single first bracket protrusions and double opposite first bracket protrusions (DOFBPs), are conceptualized, evaluated through CFD simulations and compared to protrusions having standard geometrical shapes, e.g. rectangular protrusions, triangular protrusions and semicircular protrusions. In the range of Reynolds numbers covered in this study, the microchannel having an opposed T-junction and DOFBPs is found to provide good mixing. A hybrid approach relying on the modification of microfluidic junctions as well as wall protrusions for enhancing microfluidic mixing is also evaluated. The microchannel based on the hybrid approach of an OA 10°-20°-165° WY-junction and DOFBPs is also found to provide very good mixing for a wide range of Reynolds numbers.

  10. Trapping of oxygen vacancies on twin walls of CaTiO3: a computer simulation study

    International Nuclear Information System (INIS)

    Calleja, Mark; Dove, Martin T; Salje, Ekhard K H

    2003-01-01

    We have studied the atomic structure of [001] 90 deg. rotation twin walls in orthorhombic CaTiO 3 (symmetry Pbnm) at low temperature (10 K) and their effects on oxygen vacancies. The wall thickness was found to be 2.3 nm at T || T c and it was found that it is energetically favourable for such vacancies to reside in the wall, particularly when bridging titania ions in the (001) plane. The binding energy of an oxygen vacancy in the wall with respect to the bulk is calculated to be ≤ 1.2 eV

  11. Impact of IPMOE on nursing tasks in the medical ward: A time-motion study

    Directory of Open Access Journals (Sweden)

    Ming Leung

    2018-01-01

    Conclusion: Our study had shown the time motion observation could be applied to measure the impact of the IPMOE in a busy clinical setting. Through classification of activities, validation, objective measurement and longitudinal evaluation, the method could be applied in various systems as well as different clinical settings in measure efficiency.

  12. Using a Computer Microphone Port to Study Circular Motion: Proposal of a Secondary School Experiment

    Science.gov (United States)

    Soares, A. A.; Borcsik, F. S.

    2016-01-01

    In this work we present an inexpensive experiment proposal to study the kinematics of uniform circular motion in a secondary school. We used a PC sound card to connect a homemade simple sensor to a computer and used the free sound analysis software "Audacity" to record experimental data. We obtained quite good results even in comparison…

  13. Film Studies in Motion : From Audiovisual Essay to Academic Research Video

    NARCIS (Netherlands)

    Kiss, Miklós; van den Berg, Thomas

    2016-01-01

    Our (co-written with Thomas van den Berg) ‪media rich,‬ ‪‎open access‬ ‪‎Scalar‬ ‪e-book‬ on the ‪‎Audiovisual Essay‬ practice is available online: http://scalar.usc.edu/works/film-studies-in-motion Audiovisual essaying should be more than an appropriation of traditional video artistry, or a mere

  14. Numerical study of free convection in an enclosure with two vertical isothermal walls

    International Nuclear Information System (INIS)

    Barletta, A.; Rossi di Schio, E.; Zanchini, E.; Nobile, E.; Pinto, F.

    2005-01-01

    In this paper, natural convection is studied in a 2D-cavity with two vertical isothermal walls, kept at different temperatures, and two adiabatic walls which are either straight (rectangular cavity) or elliptic (modified rectangular cavity). The local mass, momentum and energy balance equations are written in a dimensionless form and solved numerically, by means of two different software packages based on Galerkin finite element methods. With reference to a Prandtl number of 0.71, two rectangular cavities are studied: a square one and a cavity with height double than width. Then, for each value of the ratio between height and width, two cavities with elliptic boundaries are investigated. The numerical solution shows that the elliptic boundaries enhance the mean Nusselt number and the dimensionless mean kinetic energy of the fluid. (authors)

  15. Auditory motion capturing ambiguous visual motion

    Directory of Open Access Journals (Sweden)

    Arjen eAlink

    2012-01-01

    Full Text Available In this study, it is demonstrated that moving sounds have an effect on the direction in which one sees visual stimuli move. During the main experiment sounds were presented consecutively at four speaker locations inducing left- or rightwards auditory apparent motion. On the path of auditory apparent motion, visual apparent motion stimuli were presented with a high degree of directional ambiguity. The main outcome of this experiment is that our participants perceived visual apparent motion stimuli that were ambiguous (equally likely to be perceived as moving left- or rightwards more often as moving in the same direction than in the opposite direction of auditory apparent motion. During the control experiment we replicated this finding and found no effect of sound motion direction on eye movements. This indicates that auditory motion can capture our visual motion percept when visual motion direction is insufficiently determinate without affecting eye movements.

  16. Equilibrium and Thermodynamic Studies of Methane Adsorption on Multi-Walled Carbon Nanotube

    OpenAIRE

    Sanaz. Monemtabary; Mojtaba Shariati Niasar; Mohsen Jahanshahi; Ali Asghar Ghoreyshi

    2013-01-01

    In this work, The adsorption of methane onto multi-walled carbon nanotubes (MWCNTs) was studied, in which the influences of temperatureand pressure were investigated. The physical properties of the MWCNT were systematically characterised by Scanning Electron Microscopy (SEM) and Brunauere-Emmette-Teller (BET) surface area measurements. The equilibrium adsorption data were analyzed using threecommon adsorption models: Langmuir, Freundlich and Sips. All of the models fit the experimental result...

  17. Construction Time of Three Wall Types Made of Locally Sourced Materials: A Comparative Study

    OpenAIRE

    Wojciech Drozd; Agnieszka Leśniak; Sebastian Zaworski

    2018-01-01

    Similarly to any other industry, the construction sector puts emphasis on innovativeness, unconventional thinking, and alternative ideas. At present, when sustainable development, ecology, and awareness of people’s impact on the environment grow in importance, low impact buildings can become an innovative alternative construction technology for the highly industrialized construction sector. The paper presents a comparative study of three walls made of available materials used locally, which c...

  18. Study on the leakage flow through a clearance gap between two stationary walls

    Science.gov (United States)

    Zhao, W.; Billdal, J. T.; Nielsen, T. K.; Brekke, H.

    2012-11-01

    In the present paper, the leakage flow in the clearance gap between stationary walls was studied experimentally, theoretically and numerically by the computational fluid dynamics (CFD) in order to find the relationship between leakage flow, pressure difference and clearance gap. The experimental set-up of the clearance gap between two stationary walls is the simplification of the gap between the guide vane faces and facing plates in Francis turbines. This model was built in the Waterpower laboratory at Norwegian University of Science and Technology (NTNU). The empirical formula for calculating the leakage flow rate between the two stationary walls was derived from the empirical study. The experimental model is simulated by computational fluid dynamics employing the ANSYS CFX commercial software in order to study the flow structure. Both numerical simulation results and empirical formula results are in good agreement with the experimental results. The correction of the empirical formula is verified by experimental data and has been proven to be very useful in terms of quickly predicting the leakage flow rate in the guide vanes for hydraulic turbines.

  19. A Study of the correlation of the components of instructure motions during earthquakes

    International Nuclear Information System (INIS)

    Hudjian, A.H.

    1984-01-01

    The San Fernando earthquake of February 9, 1971 generated a large number of records in buildings throughout the Los Angeles basin. The correlation of the components of these instructure motions is studied with the expectation that an understanding of these in-situ motions could be helpful in the seismic analysis of equipment located in structures. Thirty-two buildings are selected that have all three components of motion recorded in the basement, midheight and top of the structure. The correlation coefficients of these motions, as a function of the orientation of recorder, is generated and evaluated. The effects of the structural characteristics on these motions are studied by comparing the top and midheight correlation functions with those of the basement records. Additionally, nine structures, whose design details are available in the technical literature, are selected for more detailed studies. Considering the fact that as-built structures tend to have a multitude of details that lead to non-symmetry, most of the structures studied tended towards increased correlation at the roof level. In a few cases the torsional response was accentuated due to a softening in one principal axis more than in the other as a direct result of structural damage. At midheight the correlation was reduced due to the fact that for highrise buildings the second and higher modes are significant contributors to the total structural response and tend to have a node at about this level for either of the principal axes. This midheight anomaly should not exist for the more rigid structures of nuclear power plant structures since these structures are dominated by the fundamental mode response

  20. Pilot study on objective measurement of abdominal wall strength in patients with ventral incisional hernia.

    Science.gov (United States)

    Parker, Michael; Goldberg, Ross F; Dinkins, Maryane M; Asbun, Horacio J; Daniel Smith, C; Preissler, Susanne; Bowers, Steven P

    2011-11-01

    Outcomes after ventral incisional hernia (VIH) repair are measured by recurrence rate and subjective measures. No objective metrics evaluate functional outcomes after abdominal wall reconstruction. This study aimed to develop testing of abdominal wall strength (AWS) that could be validated as a useful metric. Data were prospectively collected during 9 months from 35 patients. A total of 10 patients were evaluated before and after VIH repair, for a total of 45 encounters. The patients were tested simultaneously or in succession by two of three examiners. Data were collected for three tests: double leg lowering (DLL), trunk raising (TR), and supine reaching (SR). Raw data were compared and tested for validity, and continuous data were transformed to categorical data. Agreement was measured using the intraclass correlation coefficient (ICC) for DLL and using kappa for the ordinal measures. Simultaneous testing yielded the following interobserver reliability: DLL (0.96 and 0.87), TR (1.00 and 0.95), and SR (0.76). Reproducibility was assessed by consecutive tests, with correlation as follows: DLL (0.81), TR (0.81), and RCH (0.21). Due to poor interobserver reliability for the SR test compared with the DLL and TR tests, the SR test was excluded from calculation of an overall score. Based on raw data distribution from the DLL and TR tests, the DLL data were categorized into 10º increments, allowing construction of a 10-point score. The median AWS score was 5 (interquartile range [IQR], 4-7), and there was agreement within 1 point for 42 of the 45 encounters (93%). The findings from this study demonstrate that the 10-point AWS score may measure AWS in an accurate and reproducible fashion, with potential for objective description of abdominal wall function of VIH patients. This score may help to identify patients suited for abdominal wall reconstruction while measuring progress after VIH repair. Further longitudinal outcomes studies are needed.

  1. Study on flow instability for feasibility of a thin liquid film first wall

    Energy Technology Data Exchange (ETDEWEB)

    Okino, Fumito, E-mail: fumito.okino@iae.kyoto-u.ac.jp [Kyoto University Graduate School of Energy Science, Gokasho Uji, Kyoto (Japan); Kasada, Ryuta; Konishi, Satoshi [Kyoto University Institute of Advanced Energy, Gokasho Uji, Kyoto (Japan)

    2014-10-15

    Highlights: • We propose a probability of an instability wave growth on a liquid metal first wall. • Evaporated gas by the high energy flux is predicted to agitate this instability wave. • Liquid Pb-17Li with a velocity 10 m/s, the ambient gas must be below 6.2 × 10{sup 3} Pa. • This pressure corresponds to 1600 K and it is attainable under a fusion energy flux. • This probability is not yet verified so the full verifications are to be performed. - Abstract: This study proposes a probability of the evaporated gas that agitates a growing instability wave in a thin liquid film first wall. The liquid first wall was considered to be in vacuum and the effect of the ambient gas was neglected but the evaporated gas by the high energy fluxes is a probable cause of unstable wave agitation. The criterion is approximately expressed by the density ratio (Q{sub 2}) and the Weber number (We) as Q{sub 2} × We{sup 0.5} ≈ 5 × 10{sup −4}. Performed indirect experimental supported this criterion. For a case study of liquid Pb-17Li film with a velocity of 10 m/s, the evaporated gas pressure must be below 6.2 × 10{sup 3} Pa to maintain stable conditions. By recent study, this pressure is generated at 1600 K temperature and it is believed to be attainable by the energy fluxes on the first wall. This result is so far not confirmed so the full verification by experimental is to be performed.

  2. Uranium City radiation reduction program: further studies on remedial measures and radon infiltration routes for houses with block walls

    International Nuclear Information System (INIS)

    Leung, M.K.

    1980-01-01

    This report describes the results of tests of partial sealing of concrete block walls to prevent radon infiltration into houses in Uranium City, and gives the results of studies of radon migration through concrete block walls. Results of some laboratory tests on the effectiveness of concrete blocks as a radon barrier are included

  3. Study of frequency of operated chest wall tumors In Al Zahra hospital from 2007 to 2009,Isfahan,Iran

    Directory of Open Access Journals (Sweden)

    seyed abas Tabatabai

    2011-08-01

    Conclusion: According to the results of this study about 59% of the chest wall tumors were malignant and in the case of being hesitant about existing a mass on the chest wall, needed measurements for treatmentand and on time removal of the mass must be done.

  4. A Simulation Study of a Radiofrequency Localization System for Tracking Patient Motion in Radiotherapy

    Directory of Open Access Journals (Sweden)

    Mark Ostyn

    2016-04-01

    Full Text Available One of the most widely used tools in cancer treatment is external beam radiotherapy. However, the major risk involved in radiotherapy is excess radiation dose to healthy tissue, exacerbated by patient motion. Here, we present a simulation study of a potential radiofrequency (RF localization system designed to track intrafraction motion (target motion during the radiation treatment. This system includes skin-wearable RF beacons and an external tracking system. We develop an analytical model for direction of arrival measurement with radio frequencies (GHz range for use in a localization estimate. We use a Monte Carlo simulation to investigate the relationship between a localization estimate and angular resolution of sensors (signal receivers in a simulated room. The results indicate that the external sensor needs an angular resolution of about 0.03 degrees to achieve millimeter-level localization accuracy in a treatment room. This fundamental study of a novel RF localization system offers the groundwork to design a radiotherapy-compatible patient positioning system for active motion compensation.

  5. A Simulation Study of a Radiofrequency Localization System for Tracking Patient Motion in Radiotherapy.

    Science.gov (United States)

    Ostyn, Mark; Kim, Siyong; Yeo, Woon-Hong

    2016-04-13

    One of the most widely used tools in cancer treatment is external beam radiotherapy. However, the major risk involved in radiotherapy is excess radiation dose to healthy tissue, exacerbated by patient motion. Here, we present a simulation study of a potential radiofrequency (RF) localization system designed to track intrafraction motion (target motion during the radiation treatment). This system includes skin-wearable RF beacons and an external tracking system. We develop an analytical model for direction of arrival measurement with radio frequencies (GHz range) for use in a localization estimate. We use a Monte Carlo simulation to investigate the relationship between a localization estimate and angular resolution of sensors (signal receivers) in a simulated room. The results indicate that the external sensor needs an angular resolution of about 0.03 degrees to achieve millimeter-level localization accuracy in a treatment room. This fundamental study of a novel RF localization system offers the groundwork to design a radiotherapy-compatible patient positioning system for active motion compensation.

  6. Remote pipeline assessment and condition monitoring using low-frequency axisymmetric waves: a theoretical study of torsional wave motion

    Science.gov (United States)

    Muggleton, J. M.; Rustighi, E.; Gao, Y.

    2016-09-01

    Waves that propagate at low frequencies in buried pipes are of considerable interest in a variety of practical scenarios, for example leak detection, remote pipe detection, and pipeline condition assessment and monitoring. Particularly useful are the n = 0, or axisymmetric, modes in which there is no displacement (or pressure) variation over the pipe cross section. Previous work has focused on two of the three axisymmetric wavetypes that can propagate: the s = 1, fluid- dominated wave; and the s = 2, shell-dominated wave. In this paper, the third axisymmetric wavetype, the s = 0 torsional wave, is studied. Whilst there is a large body of research devoted to the study of torsional waves and their use for defect detection in pipes at ultrasonic frequencies, little is known about their behaviour and possible exploitation at lower frequencies. Here, a low- frequency analytical dispersion relationship is derived for the torsional wavenumber for a buried pipe from which both the wavespeed and wave attenuation can be obtained. How the torsional waves subsequently radiate to the ground surface is then investigated, with analytical expressions being presented for the ground surface displacement above the pipe resulting from torsional wave motion within the pipe wall. Example results are presented and, finally, how such waves might be exploited in practice is discussed.

  7. ELECTROPHORETIC DEPOSITION OF TIO2-MULTI-WALLED CARBON NANOTUBE COMPOSITE COATINGS: MORPHOLOGICAL STUDY

    Directory of Open Access Journals (Sweden)

    M. S. MAHMOUDI JOZEE

    2016-09-01

    Full Text Available A homogenous TiO2 / multi-walled carbon nanotubes(MWCNTs composite film were prepared by electrophoretic co-deposition from organic suspension on a stainless steel substrate.  In this study, MWCNTs was incorporated to the coating because of their long structure and their capability to be functionalized by different inorganic groups on the surface. FTIR spectroscopy showed the existence of carboxylic groups on the modified carbon nanotubes surface. The effect of applied electrical fields, deposition time and concentration of nanoparticulates on coatings morphology were investigated by scanning electron microscopy. It was found that combination of MWCNTs within TiO2 matrix eliminating micro cracks presented on TiO2 coating. Also, by increasing the deposition voltages, micro cracks were increased. SEM observation of the coatings revealed that TiO2/multi-walled carbon nanotubes coatings produced from optimized electric field was uniform and had good adhesive to the substrate.

  8. Comparison of theoretical and test results on shear wall seismic response

    International Nuclear Information System (INIS)

    Gantenbein, F.; Wang, F.; Dalbera, J.

    1991-01-01

    As reinforced concrete shear walls are important resisting components of buildings in nuclear power facilities, it is important to study their ultimate behavior under dynamic loading. An experimental and analytical work has been undertaken on shear walls with and without openings, in order to develop and validate their model. This paper is related to the walls without openings. While pretest calculations have already been reported (Wang and al. 1989) and the test results are given in Gantenbein and al. 1991, this paper is mainly related to the comparison of test and calculation results on the wall initial stiffness and the time history of the wall motion

  9. Study on electroactive and electrocatalytic surfaces of single walled carbon nanotube-modified electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Salinas-Torres, David [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain); Huerta, Francisco [Departamento de Ingenieria Textil y Papelera, Universidad Politecnica de Valencia, Plaza Ferrandiz y Carbonell, 1. E-03801 Alcoy (Spain); Montilla, Francisco, E-mail: francisco.montilla@ua.e [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain); Morallon, Emilia [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain)

    2011-02-01

    An investigation of the electrocatalysis of single-walled carbon nanotubes modified electrodes has been performed in this work. Nanotube-modified electrodes present a surface area much higher than the bare glassy carbon surfaces as determined by capacitance measurements. Several redox probes were selected for checking the reactivity of specific sites at the carbon nanotube surface. The presence of carbon nanotubes on the electrode improves the kinetics for all the reactions studied compared with the bare glassy carbon electrode with variations of the heterogeneous electron transfer rate constant up to 5 orders of magnitude. The most important effects are observed for the benzoquinone/hydroquinone and ferrocene/ferricinium redox couples, which show a remarkable improvement of their electron transfer kinetics on SWCNT-modified electrodes, probably due to strong {pi}-{pi} interaction between the organic molecules and the walls of the carbon nanotubes. For many of the reactions studied, less than 1% of the nanotube-modified electrode surface is transferring charge to species in solution. This result suggests that only nanotube tips are active sites for the electron transfer in such cases. On the contrary, the electroactive surface for the reactions of ferrocene and quinone is higher indicating that the electron transfer is produced also from the nanotube walls.

  10. Study on electroactive and electrocatalytic surfaces of single walled carbon nanotube-modified electrodes

    International Nuclear Information System (INIS)

    Salinas-Torres, David; Huerta, Francisco; Montilla, Francisco; Morallon, Emilia

    2011-01-01

    An investigation of the electrocatalysis of single-walled carbon nanotubes modified electrodes has been performed in this work. Nanotube-modified electrodes present a surface area much higher than the bare glassy carbon surfaces as determined by capacitance measurements. Several redox probes were selected for checking the reactivity of specific sites at the carbon nanotube surface. The presence of carbon nanotubes on the electrode improves the kinetics for all the reactions studied compared with the bare glassy carbon electrode with variations of the heterogeneous electron transfer rate constant up to 5 orders of magnitude. The most important effects are observed for the benzoquinone/hydroquinone and ferrocene/ferricinium redox couples, which show a remarkable improvement of their electron transfer kinetics on SWCNT-modified electrodes, probably due to strong π-π interaction between the organic molecules and the walls of the carbon nanotubes. For many of the reactions studied, less than 1% of the nanotube-modified electrode surface is transferring charge to species in solution. This result suggests that only nanotube tips are active sites for the electron transfer in such cases. On the contrary, the electroactive surface for the reactions of ferrocene and quinone is higher indicating that the electron transfer is produced also from the nanotube walls.

  11. Comparative study of collagen deposition in the colon wall of patients operated for sigmoid diverticular disease.

    Science.gov (United States)

    Pantaroto, Mário; Lopes Filho, Gaspar de Jesus; Pinto, Clovis Antonio Lopes; Antico Filho, Armando

    2015-10-01

    To investigate the deposition of collagen in the colon wall of patients with sigmoid diverticulitis. Samples of sigmoid tissue from 15 patients (disease group), seven men and eight women aged 37-77 years who underwent surgery for the treatment of diverticulitis, were selected. For the control group, specimens from five patients, three men and two women aged 19-58 years undergoing emergency surgery for sigmoid trauma were selected. These subjects had no associated diseases. The histological study of the surgical specimens was performed by staining with hematoxylin-eosin and picrosirius and using a histochemical method for collagen quantification. Collagen deposition in the colon wall in terms of area (F), glandular epithelium (E) and total area was significantly higher in the disease group compared to control (p=0.003, p=0.026 and p=0.010, respectively). The collagen volume fraction (F fraction) and muscle tissue (M fraction) were also significantly higher compared to control (p=0.044 and p=0.026, respectively). The muscle (M area) and volume fraction of glandular epithelium (E fraction) did not differ significantly between the two groups, (p=0.074 and p=1.000, respectively). In this study, collagen deposition in the colon wall of the patients operated for sigmoid diverticulitis was higher compared to patients without the disease.

  12. Numerical study of acoustically driven bubble cloud dynamics near a rigid wall.

    Science.gov (United States)

    Ma, Jingsen; Hsiao, Chao-Tsung; Chahine, Georges L

    2018-01-01

    The dynamics of a bubble cloud excited by a sinusoidal pressure field near a rigid wall is studied using a novel Eulerian/Lagrangian two-phase flow model. The effects of key parameters such as the amplitude and frequency of the excitation pressure, the cloud and bubble sizes, the void fraction, and the initial standoff distance on the bubbles' collective behavior and the resulting pressure loads on the nearby wall are investigated. The study shows that nonlinear bubble cloud dynamics becomes more pronounced and results in higher pressure loading at the wall as the excitation pressure amplitude increases. The strongest collective bubble behavior occurs at a preferred resonance frequency. At this resonance frequency, pressure peaks orders of magnitudes higher than the excitation pressure result from the bubble interaction when the amplitude of the pressure excitation is high. The numerically obtained resonance frequency is significantly different from the reported natural frequency of a spherical cloud derived from linear theory, which assumes small amplitude oscillations in an unbounded medium. At high amplitudes of the excitation, the resonance frequency decreases almost linearly with the ratio of excitation pressure amplitude to ambient pressure until the ratio is larger than one. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. A study of coronary artery rotational motion with dense scale-space optical flow in intravascular ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Danilouchkine, M G; Mastik, F; Steen, A F W van der [Department of Biomedical Engineering, Erasmus Medical Center, Ee2302, PO Box 2040, 3000 CA, Rotterdam (Netherlands)], E-mail: m.danilouchkine@ErasmusMC.nl, E-mail: f.mastik@ErasmusMC.nl, E-mail: a.vandersteen@ErasmusMC.nl

    2009-03-21

    This paper describes a novel method for estimating tissue motion in two-dimensional intravascular ultrasound (IVUS) images of a coronary artery. It is based on the classical Lukas-Kanade (LK) algorithm for optical flow (OF). The OF vector field quantifies the amount of misalignment between two consecutive frames in a sequence of images. From the theoretical standpoint, two fundamental improvements are proposed in this paper. First, using a simplified representation of the vessel wall as a medium with randomly distributed scatterers, it was shown that the OF equation satisfies the integral brightness conservation law. Second, a scale-space embedding for the OF equation was derived under the assumption of spatial consistency in IVUS acquisitions. The spatial coherence is equivalent to a locally affine motion model. The latter effectively captures and appropriately describes a complex deformation pattern of the coronary vessel wall under the varying physiological conditions (i.e. pulsatile blood pressure). The accuracy of OF tracking was estimated on the tissue-mimicking phantoms subjected to the controlled amount of angular deviation. Moreover, the performance of the classical LK and proposed approach was compared using the simulated IVUS images with an atherosclerotic lesion. The experimental results showed robust and reliable performance of up to 5{sup 0} of rotation, which is within the plausible range of circumferential displacement of the coronary arteries. Subsequently, the algorithm was used to analyze vessel wall motion in 18 IVUS pullbacks from 16 patients. The in vivo experiments revealed that the motion of coronary arteries is primarily determined by the cardiac contraction.

  14. Relationships between lumbar inter-vertebral motion and lordosis in healthy adult males: a cross sectional cohort study.

    OpenAIRE

    du Rose, A.; Breen, Alan C.

    2016-01-01

    Background Intervertebral motion impairment is widely thought to be related to chronic back disability, however, the movements of inter-vertebral pairs are not independent of each other and motion may also be related to morphology. Furthermore, maximum intervertebral range of motion (IV-RoMmax) is difficult to measure accurately in living subjects. The purpose of this study was to explore possible relationships between (IV-RoMmax) and lordosis, initial attainment rate and IV-RoMmax at other l...

  15. Experimental Study of Fuel Element Motion in HTR-PM Conveying Pipelines

    International Nuclear Information System (INIS)

    Wang Xin; Zhang Haiquan; Nie Junfeng; Li Hongke; Liu Jiguo; He Ayada

    2014-01-01

    The motion action of sphere fuel element (FE) inside fuel pipelines in HTR-PM is indeterminate. Fuel motion is closely connected with the interaction of FE and inner surface of fuel conveying pipe. In this paper, motion method of fuel elements in its conveying pipe is Experimental studied. Combined with the measurement of the fuel passing speed in stainless steel pipe and the track left by sphere ball for experiment, interaction modes of fuel and inner-surface of pipe, which is sliding friction, rolling friction and Collision, has been found. The modes of interaction can affect the speed of fuel conveying, amount of sphere waste and operation stability of fuel handling of high temperature reactor-pebble bed modules (HTR-PM). Furthermore, the motion process of fuel passing a big-elbow which is lying on the top of fuel pneumatic hoisting pipe were experimented. The result shows that the speed before and the speed after the elbow is positive correlation. But with the increase of speed before the elbow, the speed after the elbow increase less. Meanwhile the fuel conveying mode changes from friction to collision. And the conveying process is still steady. The effect can be used to controlling the speed of fuel conveying in fuel handling process of HTR-PM. (author)

  16. Study on Determination of Preceding Vehicle Motion State at the Traffic Lights Intersection

    Directory of Open Access Journals (Sweden)

    Cailin Wu

    2014-10-01

    Full Text Available In order to enhance the security of automotive safety systems and reduce traffic accidents in traffic lights intersection, In view of this, it is proposed to apply the distance measurement technology of binocular vision ranging in determination of preceding vehicle motion state at the traffic lights intersection, We study the determination of preceding vehicle motion state at the traffic lights intersection based on binocular vision. The system, which is divided into four steps, adopts the theory combining the binocular stereo vision principle and the triangulation principle. First of all, from different angles, image information with preceding vehicles and traffic lights, collected by two CCD cameras, is processed and positioned. Next, two pairs of corresponding feature matching points is obtained by using the stereo matching method. Furthermore, the distance between the cameras and the preceding vehicle, and the distance between the cameras and the traffic lights are determined, according to the camera calibration technique, the parallax disparity principle and the triangulation principle. Finally, the determination about the motion state of traffic lights intersection is determined according to the distance difference principle. Experimental results show that the design, with high measurement accuracy and application value, realize the determination of preceding vehicle’s motion state at traffic lights intersection.

  17. Mercury in Retrograde: Shaking Up the Study of Orbital Motion with Kinesthetic Learning

    Science.gov (United States)

    DeStefano, Paul; Allen, Thomas; Widenhorn, Ralf

    2018-06-01

    We are investigating the use of kinesthetic activities to teach the orbital motion of planets at the introductory astronomy level. In addition to breaking the monotony of traditional classroom settings, kinesthetic activities can allow novel connections to form between the student and the material, as established in a recent study. In our example active learning activity, two students walk along predetermined paths in the classroom, simulating the dynamics of any two real or fictional bodies in orbital motion about a common object. Each student carries a short-range, local positioning device that records its 2D position, continuously. The position data from both devices are collected on a single computer. After acquisition, the data can be used to highlight interesting features of orbital dynamics. For example, we demonstrate a particular transformation of the data that shows apparent retrograde motion arising directly from the relative motion of two bodies orbiting a common object. This activity provides students with the opportunity to observe interesting orbital dynamics on a human scale.

  18. The development of advanced robotic technology - A study on the development of Motion capturing system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Hyun; Kim, Ki Ho; Lee, Yong Woo; Park, Soo Il; Choi, Jin Sung; Kim, Hae Dong; Park, Chan Yong [System Engineering Research Institute, Taejon= (Korea, Republic of)

    1996-07-01

    Robots are used to perform jobs where the performer are exposed to the radioactivity. Good human-robot-interface is required to operate the robots easily and smoothly. It is believed that virtual reality and 3D graphics technology will be the beat solution for the good human-robot-interface. Using 3D computer graphics, complex human motions can be captured and displayed on the screen. The captured motion data can be used as the input to= control the remote robots using virtual reality technologies. Thus good human-robot-interface can be constructed. The motion capturing system developed in this study are very convenient and easy to be used to operate the robot. And the required time to operate the robot with the developed system is much shorter than to operate the robots without our motion capturing system. Therefore, efficient usage of the robot and related facilities will prolong the life time of them and reduce the manpower of the operators. The 3D data produced by our system will be used to generate commands to control the robot. 6 refs., 60 figs. (author)

  19. Multi-level nonlinear modeling verification scheme of RC high-rise wall buildings

    OpenAIRE

    Alwaeli, W.; Mwafy, A.; Pilakoutas, K.; Guadagnini, M.

    2017-01-01

    Earthquake-resistant reinforced concrete (RC) high-rise wall buildings are designed and detailed to respond well beyond the elastic range under the expected earthquake ground motions. However, despite their considerable section depth, in terms of analysis, RC walls are still often treated as linear elements, ignoring the effect of deformation compatibility. Due to the limited number of available comprehensive experimental studies on RC structural wall systems subjected to cycling loading, few...

  20. Experimental study on lateral strength of wall-slab joint subjected to lateral cyclic load

    Science.gov (United States)

    Masrom, Mohd Asha'ari; Mohamad, Mohd Elfie; Hamid, Nor Hayati Abdul; Yusuff, Amer

    2017-10-01

    Tunnel form building has been utilised in building construction since 1960 in Malaysia. This method of construction has been applied extensively in the construction of high rise residential house (multistory building) such as condominium and apartment. Most of the tunnel form buildings have been designed according to British standard (BS) whereby there is no provision for seismic loading. The high-rise tunnel form buildings are vulnerable to seismic loading. The connections between slab and shear walls in the tunnel-form building constitute an essential link in the lateral load resisting mechanism. Malaysia is undergoing a shifting process from BS code to Eurocode (EC) for building construction since the country has realised the safety threats of earthquake. Hence, this study is intended to compare the performance of the interior wall slab joint for a tunnel form structure designed based on Euro and British codes. The experiment included a full scale test of the wall slab joint sub-assemblages under reversible lateral cyclic loading. Two sub-assemblage specimens of the wall slab joint were designed and constructed based on both codes. Each specimen was tested using lateral displacement control (drift control). The specimen designed by using Eurocode was found could survive up to 3.0% drift while BS specimen could last to 1.5% drift. The analysis results indicated that the BS specimen was governed by brittle failure modes with Ductility Class Low (DCL) while the EC specimen behaved in a ductile manner with Ductility Class Medium (DCM). The low ductility recorded in BS specimen was resulted from insufficient reinforcement provided in the BS code specimen. Consequently, the BS specimen could not absorb energy efficiently (low energy dissipation) and further sustain under inelastic deformation.

  1. Experimental study of neutron streaming through steel-walled annular ducts in reactor shields

    International Nuclear Information System (INIS)

    Toshimas, M.; Nobuo, S.

    1983-01-01

    For the purpose of providing experimental data to assess neutron streaming calculations, neutron flux measurements were performed along the axes of the steel-walled annular ducts set up in a water shield of the pool-type reactor JRR-4. An annular duct simulated the air gap around the main coolant pipe. Another duct simulated the streaming path around the primary circulating pump of the integrated-type marine reactor. A 90-deg bend annular duct was also studied. In a set of measurements, the distance Z between the core center and the duct axis and the annular gap width delta were taken as parameters, that is, Z = 0, 80, and 160 cm and delta = 2.2, 4.7, and 10.1 cm. The reaction rates and the fluxes measured by the activation method are given in terms of absolute magnitude within an accuracy of + or - 30%. An empirical formula is derived based on those measured data, which describes the axial distribution of the neutron flux in the steel-walled annular duct in reactor shields. It is expressed by a simple function of the axial distance in units of the square root of the line-of-sight area, S /SUB l/ . The accuracy of the formula is examined by taking into account the duct location with respect to the reactor core, the neutron energy, the steel wall thickness, and the media outside of the steel wall. The accuracy of the formula is, in general, <30% in the axial distance between 3√S /SUB l/ and 30√S /SUB l/

  2. Characterization of atherosclerotic disease in thoracic aorta: A 3D, multicontrast vessel wall imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Changwu [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Department of Radiology, The Second Clinical Medical College, Yangzhou University, Yangzhou (China); Qiao, Huiyu; He, Le [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Yuan, Chun [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Department of Radiology, University of Washington, Seattle, WA (United States); Chen, Huijun; Zhang, Qiang; Li, Rui [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Wang, Wei; Du, Fang [Department of Radiology, The Second Clinical Medical College, Yangzhou University, Yangzhou (China); Li, Cheng, E-mail: cjr.licheng@vip.163.com [Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing (China); Zhao, Xihai, E-mail: xihaizhao@tsinghua.edu.cn [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China)

    2016-11-15

    Purpose: To investigate the characteristics of plaque in the thoracic aorta using three dimensional multicontrast magnetic resonance imaging. Materials and methods: Elderly subjects (≥60 years) were recruited in this study. Thoracic aorta was imaged on a 3.0T MR scanner by acquiring multicontrast sequences. The plaque burden was evaluated by measuring lumen area, wall area, wall thickness, and normalized wall index. The presence or absence of plaque and intraplaque hemorrhage (IPH)/mural thrombus (MT) were identified. The characteristics of atherosclerosis among different thoracic aorta segments (AAO: ascending aorta; AOA: aortic arch, and DOA: descending aorta) were determined. Results: Of 66 recruited subjects (mean age 72.3 ± 6.2 years, 30 males), 55 (83.3%) had plaques in the thoracic aorta. The prevalence of plaque in AAO, AOA, and DAO was 5.4%, 72.7%, and 71.2%, respectively. In addition, 21.2% of subjects were found to have lesions with IPH/MT in the thoracic aorta. The prevalence of IPH/MT in segment of AAO, AOA and DAO was 0%, 13.6%, and 12.1%, respectively. The aortic wall showed the highest NWI in DAO (34.1% ± 4.8%), followed by AOA (31.2% ± 5%), and AAO (26.8% ± 3.3%) (p < 0.001). Conclusion: Three dimensional multicontrast MR imaging is capable of characterizing atherosclerotic plaques in the thoracic aorta. The findings of high prevalence of plaques and the presence of high risk plaques in the thoracic aorta suggest early screening for aortic vulnerable lesions in the elderly.

  3. Characterization of atherosclerotic disease in thoracic aorta: A 3D, multicontrast vessel wall imaging study

    International Nuclear Information System (INIS)

    Zhou, Changwu; Qiao, Huiyu; He, Le; Yuan, Chun; Chen, Huijun; Zhang, Qiang; Li, Rui; Wang, Wei; Du, Fang; Li, Cheng; Zhao, Xihai

    2016-01-01

    Purpose: To investigate the characteristics of plaque in the thoracic aorta using three dimensional multicontrast magnetic resonance imaging. Materials and methods: Elderly subjects (≥60 years) were recruited in this study. Thoracic aorta was imaged on a 3.0T MR scanner by acquiring multicontrast sequences. The plaque burden was evaluated by measuring lumen area, wall area, wall thickness, and normalized wall index. The presence or absence of plaque and intraplaque hemorrhage (IPH)/mural thrombus (MT) were identified. The characteristics of atherosclerosis among different thoracic aorta segments (AAO: ascending aorta; AOA: aortic arch, and DOA: descending aorta) were determined. Results: Of 66 recruited subjects (mean age 72.3 ± 6.2 years, 30 males), 55 (83.3%) had plaques in the thoracic aorta. The prevalence of plaque in AAO, AOA, and DAO was 5.4%, 72.7%, and 71.2%, respectively. In addition, 21.2% of subjects were found to have lesions with IPH/MT in the thoracic aorta. The prevalence of IPH/MT in segment of AAO, AOA and DAO was 0%, 13.6%, and 12.1%, respectively. The aortic wall showed the highest NWI in DAO (34.1% ± 4.8%), followed by AOA (31.2% ± 5%), and AAO (26.8% ± 3.3%) (p < 0.001). Conclusion: Three dimensional multicontrast MR imaging is capable of characterizing atherosclerotic plaques in the thoracic aorta. The findings of high prevalence of plaques and the presence of high risk plaques in the thoracic aorta suggest early screening for aortic vulnerable lesions in the elderly.

  4. Model-based control of the resistive wall mode in DIII-D: A comparison study

    International Nuclear Information System (INIS)

    Dalessio, J.; Schuster, E.; Humphreys, D.A.; Walker, M.L.; In, Y.; Kim, J.-S.

    2009-01-01

    One of the major non-axisymmetric instabilities under study in the DIII-D tokamak is the resistive wall mode (RWM), a form of plasma kink instability whose growth rate is moderated by the influence of a resistive wall. One of the approaches for RWM stabilization, referred to as magnetic control, uses feedback control to produce magnetic fields opposing the moving field that accompanies the growth of the mode. These fields are generated by coils arranged around the tokamak. One problem with RWM control methods used in present experiments is that they predominantly use simple non-model-based proportional-derivative (PD) controllers requiring substantial derivative gain for stabilization, which implies a large response to noise and perturbations, leading to a requirement for high peak voltages and coil currents, usually leading to actuation saturation and instability. Motivated by this limitation, current efforts in DIII-D include the development of model-based RWM controllers. The General Atomics (GA)/Far-Tech DIII-D RWM model represents the plasma surface as a toroidal current sheet and characterizes the wall using an eigenmode approach. Optimal and robust controllers have been designed exploiting the availability of the RWM dynamic model. The controllers are tested through simulations, and results are compared to present non-model-based PD controllers. This comparison also makes use of the μ structured singular value as a measure of robust stability and performance of the closed-loop system.

  5. Study of the Wall Paintings of the Cenador Del Leon in the Real Alcazar of Seville

    Science.gov (United States)

    Robador, Maria Dolores; Mancera, Inmaculada; Perez-Maqueda, Rafael; Albardonedo, Antonio

    2017-10-01

    The paintings on the walls of the Cenador del Leon located in the gardens of the Real Alcazar in Seville next to the Pabellon de Carlos V in the Jardin Ingles area have been studied. The components of the wall paintings cross-sections, which were prepared using small samples taken from the walls of Cenador del Leon, were characterized using infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis. The cross-sections of the collected samples indicated that the paint layer is well adhered to the preparation layer without any discontinuity, and only one carbonation layer exists at the top of the sequence of layers. These data suggest that the paint was applied on a fresco surface, and therefore, the adopted technique was fresco. Based on the different elements detected by EDX analysis of the cross-sections, the detected pigments included iron oxides accompanied by clay minerals (or earths) in the red pink, golden yellow and yellow colours, blue smelt for the blue colour and basic copper chloride (atacamite) for the green colour. In one sample, the particles were composed of Ba and S from barium sulphate and Ti and O from rutile titanium oxide due to a modern pigment.

  6. Study of the ventilatory lung motion imaging in primary lung cancer

    International Nuclear Information System (INIS)

    Fujii, Tadashige; Tanaka, Masao; Yazaki, Yosikazu; Kitabayashi, Hiroshi; Sekiguchi, Morie.

    1996-01-01

    Using perfusion lung scintigrams with Tc-99m macroaggregated alubumin at maximal inspiration (I) and expiration (E), images of the ventilatory lung motion, which was calculated and delineated by an expression as (E-I)/I, were obtained in 84 cases with primary lung cancer, and its clinical significance in the diagnosis of primary lung cancer was studied. The image of (E-I)/I consisted of positive and negative components. The former visualized the motion of the regional intrapulmonary areas and the latter showed the motion of the lung border. The sum of positive (E-I)/I in the lung with the primary lesion which was lower than that in the contralateral lung, was significantly low in cases with hilar mass, pleural effusion and TNM classification of T3+T4. The sum of positive (E-I)/I in both lungs and vital capacity was relatively low in cases with hilar mass, pleural effusion, TNM classification of T3+T4 and M1. The distribution pattern of pulmonary perfusion and positive (E-I)/I was fairly matched in 48 cases, but mismatch was observed in 36 cases. In the image of negative (E-I)/I, decreased motion of the lung border including the diaphragm was shown in cases with pleural adhesion and thickening, pleural effusion, phrenic nerve palsy and other conditions with hypoventilation. This technique seems to be useful for the estimation of regional pulmonary function of pulmonary perfusion and lung motion, the extent and pathophysiology of primary lung cancer. (author)

  7. Study of the ventilatory lung motion imaging in primary lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Tadashige [Shinshu Univ., Matsumoto, Nagano (Japan). Shool of Allied Medical Sciences; Tanaka, Masao; Yazaki, Yosikazu; Kitabayashi, Hiroshi; Sekiguchi, Morie

    1996-12-01

    Using perfusion lung scintigrams with Tc-99m macroaggregated alubumin at maximal inspiration (I) and expiration (E), images of the ventilatory lung motion, which was calculated and delineated by an expression as (E-I)/I, were obtained in 84 cases with primary lung cancer, and its clinical significance in the diagnosis of primary lung cancer was studied. The image of (E-I)/I consisted of positive and negative components. The former visualized the motion of the regional intrapulmonary areas and the latter showed the motion of the lung border. The sum of positive (E-I)/I in the lung with the primary lesion which was lower than that in the contralateral lung, was significantly low in cases with hilar mass, pleural effusion and TNM classification of T3+T4. The sum of positive (E-I)/I in both lungs and vital capacity was relatively low in cases with hilar mass, pleural effusion, TNM classification of T3+T4 and M1. The distribution pattern of pulmonary perfusion and positive (E-I)/I was fairly matched in 48 cases, but mismatch was observed in 36 cases. In the image of negative (E-I)/I, decreased motion of the lung border including the diaphragm was shown in cases with pleural adhesion and thickening, pleural effusion, phrenic nerve palsy and other conditions with hypoventilation. This technique seems to be useful for the estimation of regional pulmonary function of pulmonary perfusion and lung motion, the extent and pathophysiology of primary lung cancer. (author)

  8. Comparative study of joint range of motion in children between 7 and 12 years of age from different gender

    Directory of Open Access Journals (Sweden)

    S.I.L. Melo

    2011-01-01

    Full Text Available The aim of the study was to evaluate and compare active and passive joint range of motion in children in relation to gender and age. This study involved 103 children (43 boys and 60 girls categorized into two groups: G1 (7 to 9 years old and G2 (10 to 12 years old. The flexitest protocol, active and passive, and the SAPO® were used to evaluate joint range of motion. A paired t test was applied to compare active and passive joint range of motion and an independent t test (p < .05 was used to compare active and passive range of motion between gender and age. Results showed that the passive joint ranges of motion of the lower limbs are higher than active motion (p < .001. Girls presented greater passive ankle flexion than boys did (p = .002. Children between 7 and 12 years of age presented similar standards of joint range of motion of low limb. Significant differences were found between passive and active angular range of motion in the hip, knee and ankle. There were no differences between boys and girls in the joint range of motion as well as among age groups.

  9. Plasma-wall Interaction Studies in the Start-up Phase of TJ-II

    International Nuclear Information System (INIS)

    De la Cal, E.; Tabares, F.L.; Tafalla, D.

    1998-01-01

    The aim of this work is to present some first plasma-wall interaction studies made during the first experimental campaign of TJ-II. The different sections contain independent contributions presented orally in the fusion division of the Euratom-Ciemat association during 1998: I. Density limit during the start-up phase of TJ-II : are we limited by radiation?. II. Temporal evolution of oxygen in the plasma during an experimental day. III. The contribution of helium to the plasma electron density IV. First studies of the S.O.L. diffusion coefficient and its dependence with the boundary plasma parameters. (Author) 3 refs

  10. The Application of KINECT Motion Sensing Technology in Game-Oriented Study

    Directory of Open Access Journals (Sweden)

    Hui Yu Yang

    2014-03-01

    Full Text Available The learning environment based on the KINECT Motion Sensing technology is able to fully mobilize the learners' multi-sensory organs, closely combine study with sports and enhance human-computer interactions, which can be conducive to the learners' health, greatly increase the relishes of learning and promote effective learning in the game, and finally compensate for the shortage of human-computer interactions in the traditional mouse and keyboard mode. The article elaborates on the KINECT Motion Sensing Technology and its educational applications status by analyzing its effective supports for game-oriented studying environment, based on which the article establishes a game-oriented learning environment. Eventually the article reveals an applicable case of game-oriented teaching and learning as a reference for related researches.

  11. Energy efficient piston configuration for effective air motion – A CFD study

    International Nuclear Information System (INIS)

    Gnana Sagaya Raj, Antony Raj; Mallikarjuna, Jawali Maharudrappa; Ganesan, Venkitachalam

    2013-01-01

    Highlights: ► All piston crown show similar flow pattern for experimental and simulated studies. ► Piston position plays a predominant role in the air pattern inside the cylinder. ► The flat bowl piston shows higher TKE compared to all other piston crown shape. ► The turbulence intensity and length scale are higher for flat bowl piston. ► The quantitative error between the CFD and PIV analysis is about 5%. -- Abstract: Air motion inside the cylinder is very important from the point of view of energy efficiency. In this direction, piston configuration plays a very crucial role. This study is concerned with the CFD analysis of in-cylinder air motion coupled with the comparison of predicted results with the experimental results available in the literature. Four configurations viz., flat, inclined, centre bowl and inclined offset bowl pistons have been studied. For numerical analysis STAR-CD CFD software has been used. Experimental results available in the literature for comparison are obtained by PIV measurements. From this study, it is concluded that a centre bowl on flat piston is found to be the best from the point of view of tumble ratio, turbulent kinetic energy, turbulent intensity and turbulent length scale which play very important role in imparting proper air motion, there by increasing the energy efficiency of the engine.

  12. The Application of KINECT Motion Sensing Technology in Game-Oriented Study

    OpenAIRE

    Hui Yu Yang; Hao Zhang; Wei Xu; Ping Jian Zhang; Liang Ming Xu

    2014-01-01

    The learning environment based on the KINECT Motion Sensing technology is able to fully mobilize the learners' multi-sensory organs, closely combine study with sports and enhance human-computer interactions, which can be conducive to the learners' health, greatly increase the relishes of learning and promote effective learning in the game, and finally compensate for the shortage of human-computer interactions in the traditional mouse and keyboard mode. The article elaborates on the KINECT Mot...

  13. The difference between the perception of absolute and relative motion: A reaction time study

    NARCIS (Netherlands)

    J.B.J. Smeets (Jeroen); E. Brenner (Eli)

    1994-01-01

    textabstractWe used a reaction-time paradigm to examine the extent to which motion detection depends on relative motion. In the absence of relative motion, the responses could be described by a simple model based on the detection of a fixed change in position. If relative motion was present, the

  14. An empirical study using range of motion and pain score as determinants for continuous passive motion: outcomes following total knee replacement surgery in an adult population.

    Science.gov (United States)

    Tabor, Danielle

    2013-01-01

    The continuous passive motion (CPM) machine is one means by which to rehabilitate the knee after total knee replacement surgery. This study sought to determine which total knee replacement patients, if any, benefit from the use of the CPM machine. For the study period, most patients received active physical therapy. Patients were placed in the CPM machine if, on postoperative day 1, they had a range of motion less than or equal to 45° and/or pain score of 8 or greater on a numeric rating scale of 0-10, 0 being no pain and 10 being the worst pain. Both groups of patients healed at similar rates. The incidence of adverse events, length of stay, and functional outcomes was comparable between groups. Given the demonstrated lack of relative benefit to the patient and the cost of the CPM, this study supported discontinuing the routine use of the CPM.

  15. A Grade 6 Project in the Social Studies: The Wall of Old Jerusalem.

    Science.gov (United States)

    Ediger, Marlow

    1993-01-01

    Presents a classroom lesson based on the walls of old Jerusalem. Maintains that cooperative-learning techniques used to build a model of the wall helped students understand the meaning of the original wall and the division of modern-day Jerusalem. (CFR)

  16. Experimental study on the heat transfer characteristics of a nuclear reactor containment wall cooled by gravitationally falling water

    Science.gov (United States)

    Pasek, Ari D.; Umar, Efrison; Suwono, Aryadi; Manalu, Reinhard E. E.

    2012-06-01

    Gravitationally falling water cooling is one of mechanism utilized by a modern nuclear Pressurized Water Reactor (PWR) for its Passive Containment Cooling System (PCCS). Since the cooling is closely related to the safety, water film cooling characteristics of the PCCS should be studied. This paper deals with the experimental study of laminar water film cooling on the containment model wall. The influences of water mass flow rate and wall heat rate on the heat transfer characteristic were studied. This research was started with design and assembly of a containment model equipped with the water cooling system, and calibration of all measurement devices. The containment model is a scaled down model of AP 1000 reactor. Below the containment steam is generated using electrical heaters. The steam heated the containment wall, and then the temperatures of the wall in several positions were measure transiently using thermocouples and data acquisition. The containment was then cooled by falling water sprayed from the top of the containment. The experiments were done for various wall heat rate and cooling water flow rate. The objective of the research is to find the temperature profile along the wall before and after the water cooling applied, prediction of the water film characteristic such as means velocity, thickness and their influence to the heat transfer coefficient. The result of the experiments shows that the wall temperatures significantly drop after being sprayed with water. The thickness of water film increases with increasing water flow rate and remained constant with increasing wall heat rate. The heat transfer coefficient decreases as film mass flow rate increase due to the increases of the film thickness which causes the increasing of the thermal resistance. The heat transfer coefficient increases slightly as the wall heat rate increases. The experimental results were then compared with previous theoretical studied.

  17. Numerical study of natural melt convection in cylindrical cavity with hot walls and cold bottom sink

    Directory of Open Access Journals (Sweden)

    Ahmanache Abdennacer

    2013-01-01

    Full Text Available Numerical study of natural convection heat transfer and fluid flow in cylindrical cavity with hot walls and cold sink is conducted. Calculations are performed in terms of the cavity aspect ratio, the heat exchanger length and the thermo physical properties expressed via the Prandtl number and the Rayleigh number. Results are presented in the form of isotherms, streamlines, average Nusselt number and average bulk temperature for a range of Rayleigh number up to 106. It is observed that Rayleigh number and heat exchanger length influences fluid flow and heat transfer, whereas the cavity aspect ratio has no significant effects.

  18. Overview of wall probes for erosion and deposition studies in the TEXTOR tokamak

    Directory of Open Access Journals (Sweden)

    M. Rubel

    2017-05-01

    Full Text Available An overview of diagnostic tools – test limiters and collector probes – used over the years for material migration studies in the TEXTOR tokamak is presented. Probe transfer systems are shown and their technical capabilities are described. This is accompanied by a brief presentation of selected results and conclusions from the research on material erosion – deposition processes including tests of candidate materials (e.g. W, Mo, carbon-based composites for plasma-facing components in controlled fusion devices. The use of tracer techniques and methods for analysis of materials retrieved from the tokamak are summarized. The impact of research on the reactor wall technology is addressed.

  19. Dynamics Of Human Motion The Case Study of an Examination Hall

    Science.gov (United States)

    Ogunjo, Samuel; Ajayi, Oluwaseyi; Fuwape, Ibiyinka; Dansu, Emmanuel

    Human behaviour is difficult to characterize and generalize due to ITS complex nature. Advances in mathematical models have enabled human systems such as love interaction, alcohol abuse, admission problem to be described using models. This study investigates one of such problems, the dynamics of human motion in an examination hall with limited computer systems such that students write their examination in batches. The examination is characterized by time (t) allocated to each students and difficulty level (dl) associated with the examination. A stochastic model based on the difficulty level of the examination was developed for the prediction of student's motion around the examination hall. A good agreement was obtained between theoretical predictions and numerical simulation. The result obtained will help in better planning of examination session to maximize available resources. Furthermore, results obtained in the research can be extended to other areas such as banking hall, customer service points where available resources will be shared amongst many users.

  20. Molecular motion of micellar solutes: a 13C NMR relaxation study

    International Nuclear Information System (INIS)

    Stark, R.E.; Kasakevich, M.L.; Granger, J.W.

    1982-01-01

    A series of simple NMR relaxation experiments have been performed on nitrobenzene and aniline dissolved in the ionic detergents sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB). Using 13 C relaxation rates at various molecular sites, and comparing data obtained in organic media with those for micellar solutions, the viscosity at the solubilization site was estimated and a detailed picture of motional restrictions imposed by the micellar enviroment was derived. Viscosities of 8 to 17 cp indicate a rather fluid environment for solubilized nitrobenzene; both additives exhibit altered motional preferences in CTAB solutions only. As an aid in interpretation of the NMR data, quasi-elastic light scattering and other physical techniques have been used to evaluate the influence of organic solutes on micellar size and shape. The NMR methods are examined critically in terms of their general usefulness for studies of solubilization in detergent micelles. 48 references

  1. Optical surface scanning for respiratory motion monitoring in radiotherapy: a feasibility study

    DEFF Research Database (Denmark)

    Bekke, Susanne Lise; Mahmood, Faisal; Helt-Hansen, Jakob

    2014-01-01

    Purpose. We evaluated the feasibility of a surface scanning system (Catalyst) for respiratory motion monitoring of breast cancer patients treated with radiotherapy in deep inspiration breath-hold (DIBH). DIBH is used to reduce the radiation dose to the heart and lung. In contrast to RPM, a compet......Purpose. We evaluated the feasibility of a surface scanning system (Catalyst) for respiratory motion monitoring of breast cancer patients treated with radiotherapy in deep inspiration breath-hold (DIBH). DIBH is used to reduce the radiation dose to the heart and lung. In contrast to RPM...... and 3: the Quasar phantom was used to study if the angle of the monitored surface affects the amplitude of the recorded signal. Results. Experiment 1: we observed comparable period estimates for both systems. The amplitudes were 8 ± 0.1 mm (Catalyst) and 4.9 ± 0.1 mm (RPM). Independent check with in...... 1. Experiment 3: an increased (fixed) surface angle during breathing motion resulted in an overestimated amplitude with RPM, while the amplitude estimated by Catalyst was unaffected. Conclusion. Our study showed that Catalyst can be used as a better alternative to the RPM. With Catalyst...

  2. Effects of Maternal Valium Administration on Fetal MRI Motion Artifact: A Comparison Study at High Altitude.

    Science.gov (United States)

    Meyers, Mariana L; Mirsky, David M; Dannull, Kimberly A; Tong, Suhong; Crombleholme, Timothy M

    2017-01-01

    Fetal MRI is performed without sedation. In cases of maternal claustrophobia or when reduction of fetal motion is critical, benzodiazepines may help. The purpose of this study was to evaluate the effects of low-dose benzodiazepine on fetal motion MRI and its effect on maternal oxygen levels at higher elevation. A total of 131 fetal MRI scans performed from March 2012 through December 2013 were studied. Nineteen of the cases were performed following Valium administration. Images were graded with a 5-point Likert scale. Using pulse oximetry, maternal oxygen levels were recorded. Results were analyzed for each category combining 3 readers' interpretations. Using a 2-sample t test model, the average imaging scores were better for the control than the Valium group (p = 0.0139). Maternal oxygen levels at different times and positions were compared using independent 2-sample t test between the Valium and control groups showing no change in O2 saturation, except when controlling for altitude and gestational age (p = 0.0326). Administration of low-dose Valium did not decrease fetal motion on MRI. Valium did not pose any risk of maternal hypoxemia, except when controlling for altitude and gestational age on supine position. Thus, caution should be exercised to prevent the risk of fetal hypoxemia. © 2016 S. Karger AG, Basel.

  3. A Comparative Study of Sample Preparation for Staining and Immunodetection of Plant Cell Walls by Light Microscopy

    Science.gov (United States)

    Verhertbruggen, Yves; Walker, Jesse L.; Guillon, Fabienne; Scheller, Henrik V.

    2017-01-01

    Staining and immunodetection by light microscopy are methods widely used to investigate plant cell walls. The two techniques have been crucial to study the cell wall architecture in planta, its deconstruction by chemicals or cell wall-degrading enzymes. They have been instrumental in detecting the presence of cell types, in deciphering plant cell wall evolution and in characterizing plant mutants and transformants. The success of immunolabeling relies on how plant materials are embedded and sectioned. Agarose coating, wax and resin embedding are, respectively, associated with vibratome, microtome and ultramicrotome sectioning. Here, we have systematically carried out a comparative analysis of these three methods of sample preparation when they are applied for cell wall staining and cell wall immunomicroscopy. In order to help the plant community in understanding and selecting adequate methods of embedding and sectioning for cell wall immunodetection, we review in this article the advantages and limitations of these three methods. Moreover, we offer detailed protocols of embedding for studying plant materials through microscopy. PMID:28900439

  4. In vitro study of near-wall flow in a cerebral aneurysm model with and without coils.

    Science.gov (United States)

    Goubergrits, L; Thamsen, B; Berthe, A; Poethke, J; Kertzscher, U; Affeld, K; Petz, C; Hege, H-C; Hoch, H; Spuler, A

    2010-09-01

    Coil embolization procedures change the flow conditions in the cerebral aneurysm and, therefore, in the near-wall region. Knowledge of these flow changes may be helpful to optimize therapy. The goal of this study was to investigate the effect of the coil-packing attenuation on the near-wall flow and its variability due to differences in the coil structure. An enlarged transparent model of an ACA aneurysm was fabricated on the basis of CT angiography. The near-wall flow was visualized by using a recently proposed technique called Wall-PIV. Coil-packing attenuation of 10%, 15%, and 20% were investigated and compared with an aneurysmal flow without coils. Then the flow variability due to the coil introduction was analyzed in 10 experiments by using a packing attenuation of 15%. A small packing attenuation of 10% already alters the near-wall flow significantly in a large part of the aneurysmal sac. These flow changes are characterized by a slow flow with short (interrupted) path lines. An increased packing attenuation expands the wall area exposed to the altered flow conditions. This area, however, depends on the coil position and/or on the 3D coil structure in the aneurysm. To our knowledge, this is the first time the near-wall flow changes caused by coils in an aneurysm model have been visualized. It can be concluded that future hydrodynamic studies of coil therapy should include an investigation of the coil structure in addition to the coil-packing attenuation.

  5. Comparison of the effects of streptokinase and tissue plasminogen activator on regional wall motion after first myocardial infarction: analysis by the centerline method with correction for area at risk.

    Science.gov (United States)

    Cross, D B; Ashton, N G; Norris, R M; White, H D

    1991-04-01

    In a trial of streptokinase versus recombinant tissue-type plasminogen activator (rt-PA) for a first myocardial infarction, 270 patients were randomized. Regional left ventricular function was assessed in 214 patients at 3 weeks. The infarct-related artery was the left anterior descending artery in 78 patients, the right coronary artery in 122 and a dominant left circumflex artery in 14. Analysis was by the centerline method with a novel correction for the area of myocardium at risk, whereby the search region was determined by the anatomic distribution of the infarct-related artery. Infarct-artery patency at 3 weeks was 73% in the streptokinase group and 71% in the rt-PA group. Global left ventricular function did not differ between the two groups. Mean chord motion (+/- SD) in the most hypokinetic half of the defined search region was similar in the streptokinase and rt-PA groups (-2.4 +/- 1.5 versus -2.3 +/- 1.3, p = 0.63). There were no differences in hyperkinesia of the noninfarct zone. Compared with conventional centerline analysis, regional wall motion in the defined area at risk was significantly more abnormal. The two methods correlated strongly, however (r = 0.99, p less than 0.0001), and both methods produced similar overall results. Patients with a patent infarct-related artery and those with an occluded artery at the time of catheterization had similar levels of global function (ejection fraction 58 +/- 12% versus 57 +/- 12%, p = 0.58).(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Numerical study of the inlet conditions on a turbulent plane two dimensional wall jet

    Energy Technology Data Exchange (ETDEWEB)

    Kechiche, Jamel; Mhiri, Hatem [Ecole Nationale d' Ingenieurs de Monastir, Lab. de Mecanique des Fluides et de Transferts Thermiques, Monastir (Tunisia); Le Palec, Georges; Bournot, Philippe [Institut de Mecanique de Marseille, Marseille, 13 (France)

    2004-11-01

    The low Reynolds number turbulence model of Herrero et al. [Int J Heat Mass Trans 34 (1991) 711] is used in this work to study turbulent isothermal or non-isothermal plane two dimensional wall jets in stagnant surroundings. In this model, the empirical constant C{sub {mu}} = 0.09 appearing in the Kolmogorov-Prandtl relation was replaced by the function proposed by Ljuboja and Rodi [J Fluids Eng 102 (1980) 350] to take account of the damping effect of the wall on the lateral fluctuations. The system of equations governing the studied configuration is solved with a finite difference scheme using a staggered grid for numerical stability, not uniform in the two directions of the flow. In the present work, we are interested particularly in the influence of the inlet conditions at the nozzle exit on the jet characteristic parameters. The obtained results show that the inlet conditions affect the flow in the vicinity of the region of the nozzle. Starting from a certain distance, the established region is reached (auto-similar region), and the results become independent of the flow characteristics at the nozzle exit. The results are also compared to those suggested in the literature. The agreement with the experimental data is satisfactory for all studied flow configurations, which provides validation of our results. (Author)

  7. Preliminary Study on Evaluation of Impact Resistance Performance of Fiber Reinforced Concrete Walls

    International Nuclear Information System (INIS)

    Jin, Byeong Moo; Lee, Yun Seok; Kim, Young Jin; Jeon, Se Jin

    2012-01-01

    As the safety assessments of nuclear power plants for the hypothetical large civil aircraft crash should be made mandatory, studies on large aircraft-nuclear power plant impact analyses and assessments studies are actively in progress. For the safety assessment of nuclear power plants against large civil aircraft crash, it is practically impossible to conduct full-scale experiments. Therefore, analysis using general purpose numerical analysis program accompanied by scale model experiments and element experiments has been adopted for the safety assessment. The safety of nuclear power plants against large civil aircraft crash is able to be accomplished by enhancement of the impact resistance performance, such as increasing the wall thickness, increasing the strength of concrete and using the fiber reinforced concrete which is able to be acquired by relatively simple process of adding fibers to a concrete mix without significant change of design and construction. A research for the enhancement of impact resistance performance depending upon design parameters for fiber reinforced concrete, such as type of fibers and application rate, is in progress. In this study, before the safety assessment of nuclear power plants against large civil aircraft crash, we assess the impact resistance performance of concrete wall depending upon type of fibers and impact velocity of objects

  8. Preliminary Study on Evaluation of Impact Resistance Performance of Fiber Reinforced Concrete Walls

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Byeong Moo; Lee, Yun Seok; Kim, Young Jin [Daewoo E and C Co. Ltd., Suwon (Korea, Republic of); Jeon, Se Jin [Ajou University, Suwon (Korea, Republic of)

    2012-05-15

    As the safety assessments of nuclear power plants for the hypothetical large civil aircraft crash should be made mandatory, studies on large aircraft-nuclear power plant impact analyses and assessments studies are actively in progress. For the safety assessment of nuclear power plants against large civil aircraft crash, it is practically impossible to conduct full-scale experiments. Therefore, analysis using general purpose numerical analysis program accompanied by scale model experiments and element experiments has been adopted for the safety assessment. The safety of nuclear power plants against large civil aircraft crash is able to be accomplished by enhancement of the impact resistance performance, such as increasing the wall thickness, increasing the strength of concrete and using the fiber reinforced concrete which is able to be acquired by relatively simple process of adding fibers to a concrete mix without significant change of design and construction. A research for the enhancement of impact resistance performance depending upon design parameters for fiber reinforced concrete, such as type of fibers and application rate, is in progress. In this study, before the safety assessment of nuclear power plants against large civil aircraft crash, we assess the impact resistance performance of concrete wall depending upon type of fibers and impact velocity of objects

  9. In-situ Raman microprobe studies of plant cell walls: macromolecular organization and compositional variability in the secondary wall of Picea mariana (Mill.) B.S.P.

    Science.gov (United States)

    U.P. Agarwal; R.H. Atalla

    1986-01-01

    Native-state organization and distribution of cell-wall components in the secondary wall of woody tissue from P. mariana (Black Spruce) have been investigated using polarized Raman microspectroscopy. Evidence for orientation is detected through Raman intensity variations resulting from rotations of the exciting electric vector with respect to cell-wall geometry....

  10. Hydraulic properties of 3D rough-walled fractures during shearing: An experimental study

    Science.gov (United States)

    Yin, Qian; Ma, Guowei; Jing, Hongwen; Wang, Huidong; Su, Haijian; Wang, Yingchao; Liu, Richeng

    2017-12-01

    This study experimentally analyzed the influence of shear processes on nonlinear flow behavior through 3D rough-walled rock fractures. A high-precision apparatus was developed to perform stress-dependent fluid flow tests of fractured rocks. Then, water flow tests on rough-walled fractures with different mechanical displacements were conducted. At each shear level, the hydraulic pressure ranged from 0 to 0.6 MPa, and the normal load varied from 7 to 35 kN. The results show that (i) the relationship between the volumetric flow rate and hydraulic gradient of rough-walled fractures can be well fit using Forchheimer's law. Notably, both the linear and nonlinear coefficients in Forchheimer's law decrease during shearing; (ii) a sixth-order polynomial function is used to evaluate the transmissivity based on the Reynolds number of fractures during shearing. The transmissivity exhibits a decreasing trend as the Reynolds number increases and an increasing trend as the shear displacement increases; (iii) the critical hydraulic gradient, critical Reynolds number and equivalent hydraulic aperture of the rock fractures all increase as the shear displacement increases. When the shear displacement varies from 0 to 15 mm, the critical hydraulic gradient ranges from 0.3 to 2.2 for a normal load of 7 kN and increases to 1.8-8.6 for a normal load of 35 kN; and (iv) the Forchheimer law results are evaluated by plotting the normalized transmissivity of the fractures during shearing against the Reynolds number. An increase in the normal load shifts the fitted curves downward. Additionally, the Forchheimer coefficient β decreases with the shear displacement but increases with the applied normal load.

  11. A Prospective Randomized Study Comparing Manual and Wall Suction in the Performance of Bronchoalveolar Lavage.

    Science.gov (United States)

    Seijo, Luis M; Flandes, Javier; Somiedo, Maria V; Naya, Alba; Manjón, Josefina; Álvarez, Susana; Fernández-Navamuel, Iker

    2016-01-01

    Bronchoalveolar lavage (BAL) may be performed using a hand-held syringe or wall suction. The aim was to study BAL volume and diagnostic yields based on BAL technique. A total of 220 consecutive patients undergoing BAL at our center were included. Manual aspiration was performed in 115 patients (group 1), and wall suction (<50 mm Hg of negative pressure) was used in 105 patients (group 2). All bronchoscopies were performed under conscious sedation applying topical anesthesia with lidocaine. Three 50-ml sterile saline aliquots were instilled in all patients. The mean total amount of fluid recovered was 67 ± 20 ml in group 1 and 55 ± 22 ml in group 2 (p < 0.001). More patients in the manual aspiration group met American Thoracic Society criteria (recovery of ≥30% of instilled fluid) for an optimal BAL (81 vs. 59%; p < 0.001). The quantity of recovered fluid was also related to BAL location (p < 0.001) and radiologic findings (p = 0.002). Forty-eight (22%) BALs were diagnostic (23 in group 1 and 25 in group 2), including 37 positive bacterial cultures, 6 positive stains for Pneumocystis, and 5 cases of malignancy. No statistically significant difference in diagnostic yield was observed between the two groups. A BAL diagnosis was more likely in patients with certain radiologic (p = 0.033) and endoscopic findings (p = 0.001). When taking into account all bronchoscopic techniques performed during the procedure (e.g. biopsies, brushing, etc.), bronchoscopy was diagnostic in 37% of patients. Manual aspiration is superior to wall suction during BAL yielding a larger quantity of aspirate. Diagnostic yields are similar for both techniques. © 2016 S. Karger AG, Basel.

  12. Ground motion input in seismic evaluation studies: impacts on risk assessment of uniform hazard spectra

    International Nuclear Information System (INIS)

    Wu, S.C.; Sewell, R.T.

    1996-07-01

    Conservatism and variability in seismic risk estimates are studied: effects of uniform hazard spectrum (UHS) are examined for deriving probabilistic estimates of risk and in-structure demand levels, as compared to the more-exact use of realistic time history inputs (of given probability) that depend explicitly on magnitude and distance. This approach differs from the conventional in its exhaustive treatment of the ground-motion threat and in its more detailed assessment of component responses to that threat. The approximate UH-ISS (in-structure spectrum) obtained based on UHS appear to be very close to the more-exact results directed computed from scenario earthquakes. This conclusion does not depend on site configurations and structural characteristics. Also, UH-ISS has composite shapes and may not correspond to the characteristics possessed a single earthquake. The shape is largely affected by the structural property in most cases and can be derived approximately from the corresponding UHS. Motions with smooth spectra, however, will not have the same damage potential as those of more realistic motions with jagged spectral shapes. As a result, UHS-based analysis may underestimate the real demands in nonlinear structural analyses

  13. Vibrational motions associated with primary processes in bacteriorhodopsin studied by coherent infrared emission spectroscopy.

    Science.gov (United States)

    Groma, Géza I; Colonna, Anne; Martin, Jean-Louis; Vos, Marten H

    2011-03-16

    The primary energetic processes driving the functional proton pump of bacteriorhodopsin take place in the form of complex molecular dynamic events after excitation of the retinal chromophore into the Franck-Condon state. These early events include a strong electronic polarization, skeletal stretching, and all-trans-to-13-cis isomerization upon formation of the J intermediate. The effectiveness of the photoreaction is ensured by a conical intersection between the electronic excited and ground states, providing highly nonadiabatic coupling to nuclear motions. Here, we study real-time vibrational coherences associated with these motions by analyzing light-induced infrared emission from oriented purple membranes in the 750-1400 cm(-)(1) region. The experimental technique applied is based on second-order femtosecond difference frequency generation on macroscopically ordered samples that also yield information on phase and direction of the underlying motions. Concerted use of several analysis methods resulted in the isolation and characterization of seven different vibrational modes, assigned as C-C stretches, out-of-plane methyl rocks, and hydrogen out-of-plane wags, whereas no in-plane H rock was found. Based on their lifetimes and several other criteria, we deduce that the majority of the observed modes take place on the potential energy surface of the excited electronic state. In particular, the direction sensitivity provides experimental evidence for large intermediate distortions of the retinal plane during the excited-state isomerization process. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  14. Building America Case Study: Construction Guidelines for High R-Value Walls without Exterior Rigid Insulation, Cold Climate Region

    Energy Technology Data Exchange (ETDEWEB)

    2017-01-01

    High-R wall assemblies (R-40 and above) are gaining popularity in the market due to programs like the DOE's Zero Energy Ready Home program, Passive House (PH), Net Zero Energy Home (NZEH) challenges in several states, and highly incentivized retrofit programs. In response to this demand, several builders have successfully used 'double wall' systems to more practically achieve higher R-values in thicker, framed walls. To builders of conventional stick-framed homes, often one of the most appealing features of double wall systems is that there are very few new exterior details. Exterior sheathing, structural bracing, house wrap or building paper, window and door flashing, and siding attachment are usually identical to good details in conventional framed wall systems. The information presented in this guide is intended to reduce the risk of failure in these types of assemblies, increase durability, and result in a reduction of material brought to landfills due to failures and resulting decay. While this document focuses on double wall framing techniques, the majority of the information on how to properly construct and finish high R-value assemblies is applicable to all wall assemblies that do not have foam insulation installed on the exterior of the structural sheathing. The techniques presented have been shown through field studies to reduce the likelihood of mold growth and moisture related damage and are intended for builders, framing contractors, architects, and consultants involved in designing and building super insulated homes.

  15. Studies of steered arc motion and macroparticle production in PVD processing

    International Nuclear Information System (INIS)

    Craven, A.L.

    2000-03-01

    During the past decade the production industry has constantly strived to improve performance and cut costs, this has been aided by the development of high performance tools. The advancement of these tools has been accomplished by the application of hard wearing, low friction, coatings. A key process in the production of such coatings is Physical Vapour Deposition (PVD). Interest in such thin films has led to much research effort, both academic and industrial, being devoted to the area. In order that these advancements in technology continue, research into the fundamental aspects of PVD is required. This thesis describes research and experimental studies which have been performed to study the effect of 'steering' an electric arc on various aspects of its behaviour. 'Steering' of the arc is achieved by applying external magnetic fields which allow the guidance of the path of the arc. Work by earlier authors has aimed to control the arc more fully. The research presented here is based of a novel electromagnetic three coil steering array of cylindrical geometry. With such coils it is possible to vary the field profiles to a greater degree than has been previously achieved, permitting a greater range of steering arrangements/fields to be applied. The research presented is divided into two distinct areas: Firstly a number of experiments were performed to assess the effectiveness of the new steering coils on the motion of the arc. A personal computer was used here along with new arc motion monitoring electronics. This enabled the simultaneous measurement of the orbital transit times and also the degree of travel perpendicular to the steered direction of motion of the arc, as it traversed the surface of the cathode. Such information was then used to produce values for standard deviation of the arc from its steered path, velocity of the arc and a diffusion constant related to the motion of the are. Such values then allowed evaluation of the stochastic model of arc motion

  16. Studying secondary growth and bast fiber development: the hemp hypocotyl peeks behind the wall

    Directory of Open Access Journals (Sweden)

    Marc Behr

    2016-11-01

    Full Text Available Cannabis sativa L. is an annual herbaceous crop grown for the production of long extraxylary fibers, the bast fibers, rich in cellulose and used both in the textile and biocomposite sectors. Despite being herbaceous, hemp undergoes secondary growth and this is well exemplified by the hypocotyl. The hypocotyl was already shown to be a suitable model to study secondary growth in other herbaceous species, namely Arabidopsis thaliana and it shows an important practical advantage, i.e. elongation and radial thickening are temporally separated. This study focuses on the mechanisms marking the transition from primary to secondary growth in the hemp hypocotyl by analysing the suite of events accompanying vascular tissue and bast fiber development. Transcriptomics, imaging and quantification of phytohormones were carried out on four representative developmental stages (i.e. 6-9-15-20 days after sowing to provide a comprehensive overview of the events associated with primary and secondary growth in hemp. This multidisciplinary approach provides cell wall-related snapshots of the growing hemp hypocotyl and identifies marker genes associated with the young (expansins, β-galactosidases and transcription factors involved in light-related processes and the older hypocotyl (secondary cell wall biosynthetic genes and transcription factors.

  17. Theoretical and computational studies of the sheath of a planar wall

    Science.gov (United States)

    Giraudo, Martina; Camporeale, Enrico; Delzanno, Gian Luca; Lapenta, Giovanni

    2012-03-01

    We present an investigation of the stability and nonlinear evolution of the sheath of a planar wall. We focus on the electrostatic limit. The stability analysis is conducted with a fluid model where continuity and momentum equations for the electrons and ions are coupled through Poisson's equation. The effect of electron emission from the wall is studied parametrically. Our results show that a sheath instability associated with the emitted electrons can exist. Following Ref. [1], it is interpreted as a Rayleigh-Taylor instability driven by the favorable combination of the sheath electron density gradient and electric field. Fully kinetic Particle-In-Cell (PIC) simulations will also be presented to investigate whether this instability indeed exists and to study the nonlinear effect of electron emission on the sheath profiles. The simulations will be conducted with CPIC, a new electrostatic PIC code that couples the standard PIC algorithm with strategies for generation and adaptation of the computational grid. [4pt] [1] G.L. Delzanno, ``A paradigm for the stability of the plasma sheath against fluid perturbations,'' Phys. Plasmas 18, 103508 (2011).

  18. The Effects of Music on Microsurgical Technique and Performance: A Motion Analysis Study.

    Science.gov (United States)

    Shakir, Afaaf; Chattopadhyay, Arhana; Paek, Laurence S; McGoldrick, Rory B; Chetta, Matthew D; Hui, Kenneth; Lee, Gordon K

    2017-05-01

    Music is commonly played in operating rooms (ORs) throughout the country. If a preferred genre of music is played, surgeons have been shown to perform surgical tasks quicker and with greater accuracy. However, there are currently no studies investigating the effects of music on microsurgical technique. Motion analysis technology has recently been validated in the objective assessment of plastic surgery trainees' performance of microanastomoses. Here, we aimed to examine the effects of music on microsurgical skills using motion analysis technology as a primary objective assessment tool. Residents and fellows in the Plastic and Reconstructive Surgery program were recruited to complete a demographic survey and participate in microsurgical tasks. Each participant completed 2 arterial microanastomoses on a chicken foot model, one with music playing, and the other without music playing. Participants were blinded to the study objectives and encouraged to perform their best. The order of music and no music was randomized. Microanastomoses were video recorded using a digitalized S-video system and deidentified. Video segments were analyzed using ProAnalyst motion analysis software for automatic noncontact markerless video tracking of the needle driver tip. Nine residents and 3 plastic surgery fellows were tested. Reported microsurgical experience ranged from 1 to 10 arterial anastomoses performed (n = 2), 11 to 100 anastomoses (n = 9), and 101 to 500 anastomoses (n = 1). Mean age was 33 years (range, 29-36 years), with 11 participants right-handed and 1 ambidextrous. Of the 12 subjects tested, 11 (92%) preferred music in the OR. Composite instrument motion analysis scores significantly improved with playing preferred music during testing versus no music (paired t test, P music was significant even after stratifying scores by order in which variables were tested (music first vs no music first), postgraduate year, and number of anastomoses (analysis of variance, P music in

  19. A study of the effects of internal organ motion on dose escalation in conformal prostate treatments

    International Nuclear Information System (INIS)

    Happersett, Laura; Mageras, Gig S.; Zelefsky, Michael J.; Burman, Chandra M.; Leibel, Steven A.; Chui Chen; Fuks, Zvi; Bull, Sarah; Ling, C. Clifton; Kutcher, Gerald J.

    2003-01-01

    Background and purpose: To assess the effect of internal organ motion on the dose distributions and biological indices for the target and non-target organs for three different conformal prostate treatment techniques. Materials and methods: We examined three types of treatment plans in 20 patients: (1) a six field plan, with a prescribed dose of 75.6 Gy; (2) the same six field plan to 72 Gy followed by a boost to 81 Gy; and (3) a five field plan with intensity modulated beams delivering 81 Gy. Treatment plans were designed using an initial CT data set (planning) and applied to three subsequent CT scans (treatment). The treatment CT contours were used to represent patient specific organ displacement; in addition, the dose distribution was convolved with a Gaussian distribution to model random setup error. Dose-volume histograms were calculated using an organ deformation model in which the movement between scans of individual points interior to the organs was tracked and the dose accumulated. The tumor control probability (TCP) for the prostate and proximal half of seminal vesicles (clinical target volume, CTV), normal tissue complication probability (NTCP) for the rectum and the percent volume of bladder wall receiving at least 75 Gy were calculated. Results: The patient averaged increase in the planned TCP between plan types 2 and 1 and types 3 and 1 was 9.8% (range 4.9-12.5%) for both, whereas the corresponding increases in treatment TCP were 9.0% (1.3-16%) and 8.1% (-1.3-13.8%). In all patients, plans 2 and 3 (81 Gy) exhibited equal or higher treatment TCP than plan 1 (75.6 Gy). The maximum treatment NTCP for rectum never exceeded the planning constraint and percent volume of bladder wall receiving at least 75 Gy was similar in the planning and treatment scans for all three plans. Conclusion: For plans that deliver a uniform prescribed dose to the planning target volume (PTV) (plan 1), current margins are adequate. In plans that further escalate the dose to part

  20. Time and motion study for alternative mixed low-level waste treatment systems

    International Nuclear Information System (INIS)

    Biagi, C.; Vetromile, J.; Teheranian, B.

    1997-02-01

    The time and motion study was developed to look at time-related aspects of the technologies and systems studied in the Integrated Thermal Treatment Systems (ITTS) and Integrated Nonthermal Treatment Systems (INTS) studies. The INTS and ITTS studies combined technologies into systems and subsystems for evaluation. The system approach provides DOE a method of measuring advantages and disadvantages of the many technologies currently being researched. For example, technologies which are more likely to create secondary waste or require extensive pretreatment handling may be less desirable than technologies which require less support from other processes. The time and motion study was designed to address the time element in the INTS and ITTS systems studies. Previous studies have focused on material balance, cost, technical effectiveness, regulatory issues, community acceptance, and operability. This study looks at system dynamics by estimating the treatment time required for a unit of waste, from receipt to certification for shipping. Labor estimates are also developed, based on the time required to do each task for each process. This focus on time highlights critical path processes and potential bottlenecks in the INTS and ITTS systems

  1. A study on the calculation of the shielding wall thickness in medical linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Yeon [Dept. of Radiation Oncology, Dongnam Ins. of Radiological and Medical Science, Busan (Korea, Republic of); Park, Eun Tae [Dept. of Radiation Oncology, Inje University Busan Paik Hospital, Busan (Korea, Republic of); Kim, Jung Hoon [Dept. of Radiological science, college of health sciences, Catholic University of Pusan, Busan (Korea, Republic of)

    2017-06-15

    The purpose of this study is to calculate the thickness of shielding for concrete which is mainly used for radiation shielding and study of the walls constructed to shield medical linear accelerator. The optimal shielding thickness was calculated using MCNPX(Ver.2.5.0) for 10 MV of photon beam energy generated by linear accelerator. As a result, the TVL for photon shielding was formed at 50⁓100 cm for pure concrete and concrete with Boron+polyethylene at 80⁓100 cm. The neutron shielding was calculated 100⁓140 cm for pure concrete and concrete with Boron+polyethylene at 90⁓100 cm. Based on this study, the concrete is considered to be most efficient method of using steel plates and adding Boron+polyethylene th the concrete.

  2. Study of the ruining behaviour of a structure with reinforced concrete carrying walls

    International Nuclear Information System (INIS)

    Manas, B.

    1998-06-01

    Nuclear facility buildings must be constructed with the respect of para-seismic rules. These rules are defined according to the most probable seismic risk estimated for the sites. This study concerns the ruining behaviour of a structure made of reinforced concrete walls. In a first part, a preliminary study on reinforced concrete is performed with the Castem 2000 finite elements code. This study emphasizes the non-linear phenomena that take place inside the material, such as the cracking of concrete and the plasticization of steels. In a second part, predictive calculations were performed on a U-shape structure. This structure was submitted to earthquakes of various magnitudes and the response of the structure was analyzed and interpreted. (J.S.)

  3. Ab initio study of F- and Cl-functionalized single wall carbon nanotubes

    International Nuclear Information System (INIS)

    Pan, H; Feng, Y P; Lin, J Y

    2006-01-01

    First-principles calculations were carried out to study the functionalization of single wall carbon nanotubes by the chemical absorption of F and Cl atoms. Our results confirmed that the band gap of semiconductor zigzag carbon nanotubes is reduced on addition of F or Cl atoms on the walls of the nanotubes. For metallic armchair nanotubes, the doubly degenerate states crossing the Fermi level were separated by the introduction of F or Cl atoms. An additional energy level emerged near the Fermi level, due to coupling between the carbon nanotube and the F or Cl atom. For zigzag nanotubes, charge transfers of 0.27e from the tube to the Cl atom and of 0.41e to the F atom took place, while for armchair nanotubes, the charge transfers from the nanotube to Cl and F are 0.25 and 0.42e, respectively. The Cl-C and F-C bond lengths were found to be 2.09 and 1.49 A, respectively. The systems show semiconducting behaviour when charged with one electron per halogen atom, but remain metallic under hole injection, regardless of the chirality of the carbon nanotubes

  4. Experimental Study of Dry Granular Flow and Impact Behavior Against a Rigid Retaining Wall

    Science.gov (United States)

    Jiang, Yuan-Jun; Towhata, Ikuo

    2013-07-01

    Shallow slope failure in mountainous regions is a common and emergent hazard in terms of its damage to important traffic routes and local communities. The impact of dry granular flows consisting of rock fragments and other particles resulting from shallow slope failures on retaining structures has yet to be systematically researched and is not covered by current design codes. As a preliminary study of the impact caused by dry granular flows, a series of dry granular impact experiments were carried out for one model of a retaining wall. It was indirectly verified that the total normal force exerted on a retaining wall consists of a drag force ( F d), a gravitational and frictional force ( F gf), and a passive earth force ( F p), and that the calculation of F d can be based on the empirical formula defined in NF EN Eurocode 1990 ( Eurocode structuraux. Base de calcul des structures, AFNOR La plaine Saint Denis, 2003). It was also indirectly verified that, for flow with Froude number from 6 to 11, the drag coefficient ( C d) can be estimated using the previously proposed empirical parameters.

  5. Toxicology Study of Single-walled Carbon Nanotubes and Reduced Graphene Oxide in Human Sperm

    Science.gov (United States)

    Asghar, Waseem; Shafiee, Hadi; Velasco, Vanessa; Sah, Vasu R.; Guo, Shirui; El Assal, Rami; Inci, Fatih; Rajagopalan, Adhithi; Jahangir, Muntasir; Anchan, Raymond M.; Mutter, George L.; Ozkan, Mihrimah; Ozkan, Cengiz S.; Demirci, Utkan

    2016-08-01

    Carbon-based nanomaterials such as single-walled carbon nanotubes and reduced graphene oxide are currently being evaluated for biomedical applications including in vivo drug delivery and tumor imaging. Several reports have studied the toxicity of carbon nanomaterials, but their effects on human male reproduction have not been fully examined. Additionally, it is not clear whether the nanomaterial exposure has any effect on sperm sorting procedures used in clinical settings. Here, we show that the presence of functionalized single walled carbon nanotubes (SWCNT-COOH) and reduced graphene oxide at concentrations of 1-25 μg/mL do not affect sperm viability. However, SWCNT-COOH generate significant reactive superoxide species at a higher concentration (25 μg/mL), while reduced graphene oxide does not initiate reactive species in human sperm. Further, we demonstrate that exposure to these nanomaterials does not hinder the sperm sorting process, and microfluidic sorting systems can select the sperm that show low oxidative stress post-exposure.

  6. Toxicology Study of Single-walled Carbon Nanotubes and Reduced Graphene Oxide in Human Sperm.

    Science.gov (United States)

    Asghar, Waseem; Shafiee, Hadi; Velasco, Vanessa; Sah, Vasu R; Guo, Shirui; El Assal, Rami; Inci, Fatih; Rajagopalan, Adhithi; Jahangir, Muntasir; Anchan, Raymond M; Mutter, George L; Ozkan, Mihrimah; Ozkan, Cengiz S; Demirci, Utkan

    2016-08-19

    Carbon-based nanomaterials such as single-walled carbon nanotubes and reduced graphene oxide are currently being evaluated for biomedical applications including in vivo drug delivery and tumor imaging. Several reports have studied the toxicity of carbon nanomaterials, but their effects on human male reproduction have not been fully examined. Additionally, it is not clear whether the nanomaterial exposure has any effect on sperm sorting procedures used in clinical settings. Here, we show that the presence of functionalized single walled carbon nanotubes (SWCNT-COOH) and reduced graphene oxide at concentrations of 1-25 μg/mL do not affect sperm viability. However, SWCNT-COOH generate significant reactive superoxide species at a higher concentration (25 μg/mL), while reduced graphene oxide does not initiate reactive species in human sperm. Further, we demonstrate that exposure to these nanomaterials does not hinder the sperm sorting process, and microfluidic sorting systems can select the sperm that show low oxidative stress post-exposure.

  7. The risk of midgut volvulus in patients with abdominal wall defects: A multi-institutional study.

    Science.gov (United States)

    Fawley, Jason A; Abdelhafeez, Abdelhafeez H; Schultz, Jessica A; Ertl, Allison; Cassidy, Laura D; Peter, Shawn St; Wagner, Amy J

    2017-01-01

    The management of malrotation in patients with congenital abdominal wall defects has varied among surgeons. We were interested in investigating the risk of midgut volvulus in patients with gastroschisis and omphalocele to help determine if these patients may benefit from undergoing a Ladd procedure. A retrospective chart review was performed for all patients managed at three institutions born between 1/1/2000 and 12/31/2008 with a diagnosis of gastroschisis or omphalocele. Patient charts were reviewed through 12/31/2012 for occurrence of midgut volvulus or need for second laparotomy. Of the 414 patients identified with abdominal wall defects, 299 patients (72%) had gastroschisis, and 115 patients (28%) had omphalocele. The mean gestational age at birth was 36.1±2.3weeks, and the mean birth weight was 2.57±0.7kg. There were a total of 8 (1.9%) cases of midgut volvulus: 3 (1.0%) patients with gastroschisis compared to 5 patients (4.4%) with omphalocele (p=0.04). Patients with omphalocele have a greater risk of developing midgut volvulus, and a Ladd procedure should be considered during definitive repair to mitigate these risks. III; retrospective comparative study. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. AN EXPLORATION OF GRAFFITI ON UNIVERSITY’S WALLS: A CORPUS-BASED DISCOURSE ANALYSIS STUDY

    Directory of Open Access Journals (Sweden)

    Nisreen Naji Al-Khawaldeh

    2017-05-01

    Full Text Available Graffiti have received a great attention from scholars as they have been considered a vital cultural phenomenon for many years (Trahan, 2011; Divsalar & Nemati, 2012; Zakareviciute, 2014; Farnia, 2014; El-Nashar & Nayef; 2016. Although there are extensive contemporary researches on graffiti in many disciplines, such as linguistics, cultural studies, politics, art, and communication (Pietrosanti, 2010;  Farnia, 2014; Oganda, 2015, there are few studies exploring graffiti on classrooms’ walls in higher education milieus (Farnia, 2014. To the best knowledge of the researchers, very few studies were done on the Jordanian context (e.g. Al-Haj Eid, 2008; Abu-Jaber, et al., 2012 and none was done on the Jordanian universities. Therefore, this study aims at analysing the content and communicative features of writings found on universities’ classrooms’ walls, corridors, and washrooms and their relation to the socio-cultural values of the society in order to explore how universities help students voice their attitudes and thoughts. The linguistic features that characterise these writings were also examined. Graffiti-writings, which were collected from the University of Jordan and the Hashemite University, were coded and analysed using the thematic content analysis technique (Braun & Clarke, 2006 and Critical Discourse Analysis (Fairclough, 1995. The analysis of the data has shown that graffiti serve different communicative language functions related to personal, social, national, religious, political, and taboo matters. The most salient linguistic features of these graffiti are simplicity and variation. It can be concluded that graffiti are distinctive and silent ways of communication, particularly in students’ society. The study will be of great importance to linguists, sociologists, educators, administrators, teachers and parents. It is enrichment to the available literature on linguistic studies.

  9. Study on Shear Performance of Cold-formed Steel Composite Wall with New Type of stud

    Science.gov (United States)

    Wang, Chungang; Yue, Sizhe; Liu, Hong; Zhang, Zhuangnan

    2018-03-01

    The shear resistance of single oriented-strand board wall and single gypsum board wall can be improved in different degrees by increasing strength of steel. The experimental data of literatures were used, and the test specimens had been simulated and validated by ABAQUS finite element analysis. According to the research, it showed that the compressive bearing capacity of the new stud composite wall was much better than the common stud composite wall, so the establishment and research of all models had been based on the new section stud. The analysis results show that when using new type of stud the shear resistance of the single oriented-strand board wall can be improved efficiently by increasing strength of steel, but the shear resistance of the single gypsum wall can be increased little.

  10. SAR interferometry monitoring along the ancient Rome City Walls -the PROTHEGO project case study

    Science.gov (United States)

    Carta, Cristina; Cimino, Maria gabriella; Leoni, Gabriele; Marcelli, Marina; Margottini, Claudio; Spizzichino, Daniele

    2017-04-01

    Led by the Italian Institute for Environmental Protection and Research, in collaboration with NERC British Geological Survey, Geological and Mining Institute of Spain, University of Milano-Bicocca and Cyprus University of Technology, the PROTHEGO project, co-funded in the framework of JPI on Cultural Heritage EU program (2015-2018), brings an innovative contribution towards the analysis of geo-hazards in areas of cultural heritage in Europe. The project apply InSAR techniques to monitor monuments and sites that are potentially unstable due to natural geo-hazard. After the remote sensing investigation, detailed geological interpretation, hazard analysis, local-scale monitoring, advanced modeling and field surveying for some case studies is implemented. The selected case studies are: the Alhambra in Granada (ES); the Choirokoitia village (CY); the Derwent Valley Mills (UK); the Pompei archaeological site and Historical centre of Rome (IT). In this work, in particular, we will focus on ground deformation measurements (obtained by satellite SAR Interferometry) and on their interpretation with respect to the ancient Rome City Walls. The research activities carried out jointly with the Superintendence's technicians, foresee the implementation of a dedicated web GIS platform as a final repository for data storage and spatial data elaboration. The entire circuit of the ancient city walls (both Mura Aureliane and Mura Gianicolensi), was digitalized and georeferenced. All the elements (towers, gates and wall segments) were drawn and collected in order to produce a map of elements at risk. A detailed historical analysis (during the last twenty years) of the ground and structural deformations were performed. A specific data sheet of ruptures was created and fulfilled in order to produce a geographic inventory of past damage. This data sheet contains the following attributes: triggering data; typology of damage; dimension, triggering mechanism; presence of restoration works

  11. Study of air and steam leak rate through damaged concrete wall

    International Nuclear Information System (INIS)

    Abdeslam Laghcha; Gerard Debicki; Benoit Masson

    2005-01-01

    Full text of publication follows: The leak rate prediction of air and steam through a cracked concrete wall is an extremely important issue in assessing the safety of nuclear reactor containment building. Furthermore the relation between air leak rate and steam leak rate on the same wall could have some interest for safety prediction. This laboratory study investigates the transfer of fluids through a wall of 1.3 m of thickness, with a focus on two cases: one on a mechanically damaged concrete by compressive stress and another one on a crossing artificial flaw in a construction joint realized in the concrete specimen (cylindrical / section 0.1925 m 2 / length 1.3 m). The both specimens were made of ordinary concrete (compressive strength: 35 MPa). To initiate residual compressive cracks, the specimen (A) was loaded in compression under controlled strains until a level of 90% of the failure strain was reached. To create a crossing artificial flaw in a construction joint, the concrete was set in the mould in two times, the second time, a water saturated sand bed was placed on the surface of the hardened concrete to realize the flaw along a diameter of the specimen (B). The permeability of damaged concrete wall was studied comparatively under two conditions, but without appreciable stresses applied on. The first condition was at ambient temperature, a reference test of permeability, with dry air, gave the characteristics of permeability and the type of flow through the specimen. In this case, the used method consisted to proceed by stages. The imposed pressures on the exposed face were successively 0.1, 0.18, 0.23, 0.28, 0.34 and 0.42 MPa, the other face was at atmospheric pressure. The second condition was an accidental scenario with simultaneous effects of temperature and gas (a mix of air and steam) pressure applied on a face, the other one remaining at atmospheric pressure and temperature. During the test, the lateral face of the cylindrical specimen was thermally

  12. A study on the characteristics of strong ground motions in southern Korea

    International Nuclear Information System (INIS)

    Bang, Chang Eob; Lee, Kie Hwa; Kang, Tae Seob

    2001-12-01

    Ground motion characteristics in southern Korea are analyzed such as the variations of ground motion durations depending on the hypocentral distance, the earthquake magnitude and the frequency contents of the motion, and the predominant frequency of the maximum ground motion, the ratio of the horizontal to the vertical component amplitudes, the frequency dependence of the Coda Q values, the local distribution of Lg Q values using recorded data sets

  13. A study on the characteristics of strong ground motions in southern Korea

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Chang Eob; Lee, Kie Hwa; Kang, Tae Seob [Seoul National Univ., Seoul (Korea, Republic of)

    2001-12-15

    Ground motion characteristics in southern Korea are analyzed such as the variations of ground motion durations depending on the hypocentral distance, the earthquake magnitude and the frequency contents of the motion, and the predominant frequency of the maximum ground motion, the ratio of the horizontal to the vertical component amplitudes, the frequency dependence of the Coda Q values, the local distribution of Lg Q values using recorded data sets.

  14. Nanopore wall-liquid interaction under scope of molecular dynamics study: Review

    Science.gov (United States)

    Tsukanov, A. A.; Psakhie, S. G.

    2017-12-01

    The present review is devoted to the analysis of recent molecular dynamics based on the numerical studies of molecular aspects of solid-fluid interaction in nanoscale channels. Nanopore wall-liquid interaction plays the crucial role in such processes as gas separation, water desalination, liquids decontamination, hydrocarbons and water transport in nano-fractured geological formations. Molecular dynamics simulation is one of the most suitable tools to study molecular level effects occurred in such multicomponent systems. The nanopores are classified by their geometry to four groups: nanopore in nanosheet, nanotube-like pore, slit-shaped nanopore and soft-matter nanopore. The review is focused on the functionalized nanopores in boron nitride nanosheets as novel selective membranes and on the slit-shaped nanopores formed by minerals.

  15. Quantitative study of bundle size effect on thermal conductivity of single-walled carbon nanotubes

    Science.gov (United States)

    Feng, Ya; Inoue, Taiki; An, Hua; Xiang, Rong; Chiashi, Shohei; Maruyama, Shigeo

    2018-05-01

    Compared with isolated single-walled carbon nanotubes (SWNTs), thermal conductivity is greatly impeded in SWNT bundles; however, the measurement of the bundle size effect is difficult. In this study, the number of SWNTs in a bundle was determined based on the transferred horizontally aligned SWNTs on a suspended micro-thermometer to quantitatively study the effect of the bundle size on thermal conductivity. Increasing the bundle size significantly degraded the thermal conductivity. For isolated SWNTs, thermal conductivity was approximately 5000 ± 1000 W m-1 K-1 at room temperature, three times larger than that of the four-SWNT bundle. The logarithmical deterioration of thermal conductivity resulting from the increased bundle size can be attributed to the increased scattering rate with neighboring SWNTs based on the kinetic theory.

  16. Preliminary study of impact fragility to RC wall subjected to aircraft impact

    International Nuclear Information System (INIS)

    Shin, Sang Shup; Hahm, Dae Gi; Choi, In Kil

    2012-01-01

    International experience has shown that internal and external hazards such as fires, earthquakes, and aircraft impacts can be significant safety contributors to the risk to infrastructures such as nuclear power plants. Since the aircraft accident at the World Trade Center (WTC) on September 11, 2001, an aircraft impact problem has been increasingly of the interest and is one of important categories of an unexpected external hazard field. To date, aircraft impact analyses has most focused on the response analysis to the target structures. However, this preliminary study carried out an impact fragility analysis to reinforced concrete (RC) wall subjected to an aircraft impact. The aircraft velocity is used as the important variable of this study. The impact analysis of the applied Ri era's forcing function is used by Abaqus/Explicit

  17. Studies on transport phenomena in polymer solutions and suspensions flowing through tubes of tortuous wall geometry

    Science.gov (United States)

    Narayanan, C. M.

    2014-02-01

    Attempts have been made to analyse the momentum and heat transfer characteristics in tortuous flow of non-Newtonian fluids such as suspensions and polymer solutions through tubes of diverging-converging geometry. The results of the study indicate that the transfer coefficients are significantly higher in such systems as compared to the conventional couette flow (through uniform cylindrical tubes). Moreover, the simultaneous increase in pressure drop due to the tortuous wall geometry has been observed to be relatively insignificant. Fluids with different rheological characteristics such as Bingham plastic fluids, pseudoplastic fluids, Ellis model fluids and fluids obeying Reiner-Philippoff rheology have been studied. The specific advantages of these geometries in providing enhanced performance efficiency have been effectively highlighted.

  18. First wall studies of a laser-fusion hybrid reactor design

    International Nuclear Information System (INIS)

    Hovingh, J.

    1976-09-01

    The design of a first wall for a 20 MW thermonuclear power laser fusion hybrid reactor is presented. The 20 mm thick graphite first wall is located 3.5 m from the DT microexplosion with a thermonuclear yield of 10 MJ. Estimates of the energy deposition, temperature, stresses, and material vaporized from the first wall due to the interaction of the x-rays, charged particle debris, and reflected laser light with the graphite are presented, along with a brief description of the analytical methods used for these estimations. Graphite is a viable first wall material for inertially-confined fusion reactors, with lifetimes of a year possible

  19. Evaluation of collagen in connective tissue walls of odontogenic cysts--a histochemical study.

    Science.gov (United States)

    Vij, Ruchieka; Vij, Hitesh; Rao, Nirmala N

    2011-03-01

    The purpose of this study was to evaluate the nature of collagen in the connective tissue walls of odontogenic cysts, like the odontogenic keratocyst (OKC), dentigerous cyst and radicular cyst using picrosirius red stained sections. Furthermore, it was intended to assess if the capsular connective tissue can affect the nature of overlying epithelium, thus emphasizing the role of epithelial-mesenchymal interactions in biological behaviour of the cysts. The material for the study included 51 formalin-fixed paraffin-embedded tissue blocks (15 odontogenic keratocyst, 15 dentigerous cysts, 15 radicular cysts and four normal mucosa and two dental follicular tissue as controls), retrieved from the Department of Oral Pathology and Microbiology, MCODS, Manipal. Tissue blocks were sectioned at 5-μm thickness, stained with picrosirius red stain and observed with polarization and light microscopy. Few sections of OKC and dentigerous cyst exhibited greenish-yellow birefringence in sub-epithelial region, whereas others showed a yellowish-orange birefringence under polarization microscopy. Most radicular cysts had yellowish-orange to orange birefringence. Shift in colour in case OKC and dentigerous cyst was attributed to the presence of inflammation in those sections. These regions also exhibited either a change in phenotype or thickness of overlying epithelium. This technique can be used to study the nature of collagen fibres in odontogenic cyst walls. Further studies with an increased sample size and using various epithelial and mesenchymal markers and ssDNA antibodies should be carried out to confirm the effect of epithelial-mesenchymal interactions on the nature of epithelium of odontogenic cysts. © 2010 John Wiley & Sons A/S.

  20. Tight binding simulation study on zigzag single-walled carbon nanotubes

    Science.gov (United States)

    Sharma, Deepa; Jaggi, Neena; Gupta, Vishu

    2018-01-01

    Tight binding simulation studies using the density functional tight binding (DFTB) model have been performed on various zigzag single-walled carbon-nanotubes (SWCNTs) to investigate their electronic properties using DFTB module of the Material Studio Software version 7.0. Various combinations of different eigen-solvers and charge mixing schemes available in the DFTB Module have been tried to chalk out the electronic structure. The analytically deduced values of the bandgap of (9, 0) SWCNT were compared with the experimentally determined value reported in the literature. On comparison, it was found that the tight binding approximations tend to drastically underestimate the bandgap values. However, the combination of Anderson charge mixing method with standard eigensolver when implemented using the smart algorithm was found to produce fairly close results. These optimized model parameters were then used to determine the band structures of various zigzag SWCNTs. (9, 0) Single-walled Nanotube which is extensively being used for sensing NH3, CH4 and NO2 has been picked up as a reference material since its experimental bandgap value has been reported in the literature. It has been found to exhibit a finite energy bandgap in contrast to its expected metallic nature. The study is of utmost significance as it not only probes and validates the simulation route for predicting suitable properties of nanomaterials but also throws light on the comparative efficacy of the different approximation and rationalization quantum mechanical techniques used in simulation studies. Such simulation studies if used intelligently prove to be immensely useful to the material scientists as they not only save time and effort but also pave the way to new experiments by making valuable predictions.

  1. Study of Inter- and Intra-fraction Motion in Brain Tumor Patients Undergoing VMAT Treatment

    International Nuclear Information System (INIS)

    Ascencion Ybarra, Y.; Alfonso Laguardia, R.; Yartsev, S.

    2015-01-01

    Conforming dose to the tumor and sparing normal tissue can be challenging for brain tumors with complex shapes in close proximity to critical structures. The goal of this study was to evaluate the inter- and intra-fraction motion in brain tumor patients undergoing volumetric modulated arc therapy (VMAT). The image matching software was found to be very sensitive to the choice of the region of matching. It is recommended to use the same region of interest for comparing the image sets and perform the automatic matching based on bony landmarks in brain tumor cases. (Author)

  2. A Multifaceted Study of Scedosporium boydii Cell Wall Changes during Germination and Identification of GPI-Anchored Proteins

    Science.gov (United States)

    Ghamrawi, Sarah; Gastebois, Amandine; Zykwinska, Agata; Vandeputte, Patrick; Marot, Agnès; Mabilleau, Guillaume; Cuenot, Stéphane; Bouchara, Jean-Philippe

    2015-01-01

    Scedosporium boydii is a pathogenic filamentous fungus that causes a wide range of human infections, notably respiratory infections in patients with cystic fibrosis. The development of new therapeutic strategies targeting S. boydii necessitates a better understanding of the physiology of this fungus and the identification of new molecular targets. In this work, we studied the conidium-to-germ tube transition using a variety of techniques including scanning and transmission electron microscopy, atomic force microscopy, two-phase partitioning, microelectrophoresis and cationized ferritin labeling, chemical force spectroscopy, lectin labeling, and nanoLC-MS/MS for cell wall GPI-anchored protein analysis. We demonstrated that the cell wall undergoes structural changes with germination accompanied with a lower hydrophobicity, electrostatic charge and binding capacity to cationized ferritin. Changes during germination also included a higher accessibility of some cell wall polysaccharides to lectins and less CH3/CH3 interactions (hydrophobic adhesion forces mainly due to glycoproteins). We also extracted and identified 20 GPI-anchored proteins from the cell wall of S. boydii, among which one was detected only in the conidial wall extract and 12 only in the mycelial wall extract. The identified sequences belonged to protein families involved in virulence in other fungi like Gelp/Gasp, Crhp, Bglp/Bgtp families and a superoxide dismutase. These results highlighted the cell wall remodeling during germination in S. boydii with the identification of a substantial number of cell wall GPI-anchored conidial or hyphal specific proteins, which provides a basis to investigate the role of these molecules in the host-pathogen interaction and fungal virulence. PMID:26038837

  3. Domain wall energy landscapes in amorphous magnetic films with asymmetric arrays of holes

    International Nuclear Information System (INIS)

    Alija, A; Perez-Junquera, A; RodrIguez-RodrIguez, G; Velez, M; Alameda, J M; MartIn, J I; Marconi, V I; Kolton, A B; Parrondo, J M R; Anguita, J V

    2009-01-01

    Arrays of asymmetric holes have been defined in amorphous Co-Si films by e-beam lithography in order to study domain wall motion across the array subject to the asymmetric pinning potential created by the holes. Experimental results on Kerr effect magnetooptical measurements and hysteresis loops are compared with micromagnetic simulations in films with arrays of triangular holes. These show that the potential asymmetry favours forward wall propagation for flat walls but, if the wall contains a kink, net backward wall propagation is preferred at low fields, in agreement with minor loop experiments. The difference between the fields needed for forward and backward flat wall propagation increases as the size of the triangular holes is reduced, becoming maximum for 1 μm triangles, which is the characteristic length scale set by domain wall width.

  4. Domain wall energy landscapes in amorphous magnetic films with asymmetric arrays of holes

    Science.gov (United States)

    Alija, A.; Pérez-Junquera, A.; Rodríguez-Rodríguez, G.; Vélez, M.; Marconi, V. I.; Kolton, A. B.; Anguita, J. V.; Alameda, J. M.; Parrondo, J. M. R.; Martín, J. I.

    2009-02-01

    Arrays of asymmetric holes have been defined in amorphous Co-Si films by e-beam lithography in order to study domain wall motion across the array subject to the asymmetric pinning potential created by the holes. Experimental results on Kerr effect magnetooptical measurements and hysteresis loops are compared with micromagnetic simulations in films with arrays of triangular holes. These show that the potential asymmetry favours forward wall propagation for flat walls but, if the wall contains a kink, net backward wall propagation is preferred at low fields, in agreement with minor loop experiments. The difference between the fields needed for forward and backward flat wall propagation increases as the size of the triangular holes is reduced, becoming maximum for 1 µm triangles, which is the characteristic length scale set by domain wall width.

  5. Numerical study on the electron—wall interaction in a Hall thruster with segmented electrodes placed at the channel exit

    International Nuclear Information System (INIS)

    Qing Shao-Wei; E Peng; Xu Dian-Guo; Duan Ping

    2013-01-01

    Electron—wall interaction is always recognized as an important physical problem because of its remarkable influences on thruster discharge and performance. Based on existing theories, an electrode is predicted to weaken electron—wall interaction due to its low secondary electron emission characteristic. In this paper, the electron—wall interaction in an Aton-type Hall thruster with low-emissive electrodes placed near the exit of discharge channel is studied by a fully kinetic particle-in-cell method. The results show that the electron—wall interaction in the region of segmented electrode is indeed weakened, but it is significantly enhanced in the remaining region of discharge channel. It is mainly caused by electrode conductive property which makes equipotential lines convex toward channel exit and even parallel to wall surface in near-wall region; this convex equipotential configuration results in significant physical effects such as repelling electrons, which causes the electrons to move toward the channel center, and the electrons emitted from electrodes to be remarkably accelerated, thereby increasing electron temperature in the discharge channel, etc. Furthermore, the results also indicate that the discharge current in the segmented electrode case is larger than in the non-segmented electrode case, which is qualitatively in accordance with previous experimental results. (physics of gases, plasmas, and electric discharges)

  6. Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET-MR: Phantom and patient studies

    International Nuclear Information System (INIS)

    Huang, Chuan; Petibon, Yoann; Ouyang, Jinsong; El Fakhri, Georges; Reese, Timothy G.; Ahlman, Mark A.; Bluemke, David A.

    2015-01-01

    relatively accurate motion fields and yield tMR-based motion corrected PET images with similar image quality as those reconstructed using fully sampled tMR data. The reduction of tMR acquisition time makes it more compatible with routine clinical cardiac PET-MR studies

  7. Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET-MR: Phantom and patient studies

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chuan, E-mail: chuan.huang@stonybrookmedicine.edu [Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115 (United States); Departments of Radiology, Psychiatry, Stony Brook Medicine, Stony Brook, New York 11794 (United States); Petibon, Yoann [Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Ouyang, Jinsong; El Fakhri, Georges [Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115 (United States); Reese, Timothy G. [Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115 and Martinos Center for Biomedical Imaging, Charlestown, Massachusetts 02129 (United States); Ahlman, Mark A.; Bluemke, David A. [Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland 20892 (United States)

    2015-02-15

    relatively accurate motion fields and yield tMR-based motion corrected PET images with similar image quality as those reconstructed using fully sampled tMR data. The reduction of tMR acquisition time makes it more compatible with routine clinical cardiac PET-MR studies.

  8. Thin walls in regions with vacuum energy

    Energy Technology Data Exchange (ETDEWEB)

    Garfinkle, D [Florida Univ., Gainesville, FL (USA). Dept. of Physics; Vuille, C [Embry-Riddle Aeronautical Univ., Prescott, AZ (USA). Dept. of Math/Physical Science

    1989-12-01

    The motion of a thin wall is treated in the case where the regions on either side of the wall have vacuum energy. This treatment generalises previous results involving domain walls in vacuum and also previous results involving the properties of false vacuum bubbles. The equation of state for a domain wall is{tau} = {sigma} where {tau} is the tension in the wall and {sigma} is the energy density. We consider the motion of a more general class of walls having equation of state {tau}{Gamma}{sigma} with 0{le}{Gamma}{le}1. Spherically symmetric and planar symmetric walls are examined. We also find the global structure of the wall spacetime. (author).

  9. Cinematic study of temporomandibular joint motion using ultra-fast magnetic resonance imaging.

    Science.gov (United States)

    Manière-Ezvan, A; Havet, T; Franconi, J M; Quémar, J C; de Certaines, J D

    1999-10-01

    Magnetic Resonance Images (MRI) of the temporomandibular joint (TMJ) are usually performed to study the opening/closing movements of the mandible and have up to now been pseudodynamic step-by-step images simulating condylar motion by post-processing reconstruction. The aim of this study was: 1. to optimize a TMJ cine-imaging method to give a better clinical result than the step-by-step methods; 2. to develop an ultra-fast MRI Gradient Echo (GE) sequence for this purpose; and 3. to analyze condylar movements in the sagittal, coronal and para-axial planes during border mandibular displacements and chewing. Both TM joints were studied in six asymptomatic volunteers. The method involved a compromise between in-plane resolution, slice thickness, signal-to-noise ratio and time resolution. Routine clinical use was found to be a GE pulse sequence providing three images per second with an isometric voxel resolution of approximately two millimeters in ridge. This did not allow visualization of the disk. Using this sequence enabled real and simultaneous condylar displacement observation in the three planes of space and therefore contributed to a better functional diagnosis of pathologic TMJ motions.

  10. Understanding and Visualizing Multitasking and Task Switching Activities: A Time Motion Study to Capture Nursing Workflow.

    Science.gov (United States)

    Yen, Po-Yin; Kelley, Marjorie; Lopetegui, Marcelo; Rosado, Amber L; Migliore, Elaina M; Chipps, Esther M; Buck, Jacalyn

    2016-01-01

    A fundamental understanding of multitasking within nursing workflow is important in today's dynamic and complex healthcare environment. We conducted a time motion study to understand nursing workflow, specifically multitasking and task switching activities. We used TimeCaT, a comprehensive electronic time capture tool, to capture observational data. We established inter-observer reliability prior to data collection. We completed 56 hours of observation of 10 registered nurses. We found, on average, nurses had 124 communications and 208 hands-on tasks per 4-hour block of time. They multitasked (having communication and hands-on tasks simultaneously) 131 times, representing 39.48% of all times; the total multitasking duration ranges from 14.6 minutes to 109 minutes, 44.98 minutes (18.63%) on average. We also reviewed workflow visualization to uncover the multitasking events. Our study design and methods provide a practical and reliable approach to conducting and analyzing time motion studies from both quantitative and qualitative perspectives.

  11. Numerical study of plasma-wall transition in an oblique magnetic field

    International Nuclear Information System (INIS)

    Valsaque, Fabrice; Manfredi, Giovanni

    2001-01-01

    The interaction of a plasma with a fixed wall is investigated numerically. The ions are described by a kinetic model, while the electrons are assumed to be at thermal equilibrium. Finite Debye length effects are taken into account. An Eulerian code is used for the ion dynamics, which enables us to obtain a fine resolution of both position and velocity space. First, we analyse the effect of ionization and collisions, which bring the ion flow to supersonic velocity at the entrance of the Debye sheath (Bohm's criterion). Second, we consider a collisionless sheath with an oblique magnetic field. A magnetic presheath, which has a width of several ion gyroradii, is located between the Debye sheath and the bulk plasma. We perform a systematic numerical study of these sheaths for different incidences of the magnetic field

  12. Axial Crushing Behaviors of Thin-Walled Corrugated and Circular Tubes - A Comparative Study

    Science.gov (United States)

    Reyaz-Ur-Rahim, Mohd.; Bharti, P. K.; Umer, Afaque

    2017-10-01

    With the help of finite element analysis, this research paper deals with the energy absorption and collapse behavior with different corrugated section geometries of hollow tubes made of aluminum alloy 6060-T4. Literature available experimental data were used to validate the numerical models of the structures investigated. Based on the results available for symmetric crushing of circular tubes, models were developed to investigate corrugated thin-walled structures behavior. To study the collapse mechanism and energy absorbing ability in axial compression, the simulation was carried in ABAQUS /EXPLICIT code. In the simulation part, specimens were prepared and axially crushed to one-fourth length of the tube and the energy diagram of crushing force versus axial displacement is shown. The effect of various parameters such as pitch, mean diameter, corrugation, amplitude, the thickness is demonstrated with the help of diagrams. The overall result shows that the corrugated section geometry could be a good alternative to the conventional tubes.

  13. Objects in Motion

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

  14. Activity and stability studies of platinized multi-walled carbon nanotubes as fuel cell electrocatalysts

    DEFF Research Database (Denmark)

    Stamatin, Serban Nicolae; Borghei, Maryam; Dhiman, Rajnish

    2015-01-01

    A non-covalent functionalization for multi-walled carbon nanotubes has been used as an alternative to the damaging acid treatment. Platinum nanoparticles with similar particle size distribution have been deposited on the surface modified multi-walled carbon nanotubes. The interaction between...

  15. In-situ nanomechanical study on bending characteristics of individual multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Ping-Chi, E-mail: pctjbenchen@yahoo.com.tw [Department of Mechanical Engineering, National Chung Cheng University, Chia-Yi 621, Taiwan (China); Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chia-Yi 621, Taiwan (China); Jeng, Yeau-Ren, E-mail: imeyrj@ccu.edu.tw [Department of Mechanical Engineering, National Chung Cheng University, Chia-Yi 621, Taiwan (China); Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chia-Yi 621, Taiwan (China)

    2016-03-21

    Bending characteristics of individual thin-walled carbon nanotubes (CNTs) are investigated through a novel in-situ nanoindentation in transmission electron microscopy. Unlike thick-walled CNTs, the graphitic layers of thin ones buckle into V-shaped kinks rather than Yoshimura ripples. These kinks are found to be entirely reversible without residual plastic deformation following unloading.

  16. Specific labeling of peptidoglycan precursors as a tool for bacterial cell wall studies

    NARCIS (Netherlands)

    van Dam, V.; Olrichs, N.K.; Breukink, E.J.

    2009-01-01

    Wall chart: The predominant component of the bacterial cell wall, peptidoglycan, consists of long alternating stretches of aminosugar subunits interlinked in a large three-dimensional network and is formed from precursors through several cytosolic and membrane-bound steps. The high tolerance of the

  17. Cell wall and DNA cosegregation in Bacillus subtilis studied by electron microscope autoradiography

    International Nuclear Information System (INIS)

    Schlaeppi, J.M.; Schaefer, O.; Karamata, D.

    1985-01-01

    Cells of a Bacillus subtilis mutant deficient in both major autolytic enzyme activities were continuously labeled in either cell wall or DNA or both cell wall and DNA. After appropriate periods of chase in minimal as well as in rich medium, thin sections of cells were autoradiographed and examined by electron microscopy. The resolution of the method was adequate to distinguish labeled DNA units from cell wall units. The latter, which could be easily identified, were shown to segregate symmetrically, suggesting a zonal mode of new wall insertion. DNA units could also be clearly recognized despite a limited fragmentation; they segregated asymmetrically with respect to the nearest septum. Analysis of cells simultaneously labeled in cell wall and DNA provided clear visual evidence of their regular but asymmetrical cosegregation, confirming a previous report obtained by light microscope autoradiography. In addition to labeled wall units, electron microscopy of thin sections of aligned cells has revealed fibrillar networks of wall material which are frequently associated with the cell surface. Most likely, these structures correspond to wall sloughed off by the turnover mechanism but not yet degraded to filterable or acid-soluble components

  18. AN HST PROPER-MOTION STUDY OF THE LARGE-SCALE JET OF 3C273

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Eileen T.; Georganopoulos, Markos [University of Maryland Baltimore County, Baltimore, MD 21250 (United States); Sparks, William B. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Anderson, Jay; Marel, Roeland van der; Biretta, John; Chiaberge, Marco; Norman, Colin [Space Telescope Science Institute, Baltimore, MD 21210 (United States); Tony Sohn, Sangmo [Johns Hopkins University, Baltimore, MD 21210 (United States); Perlman, Eric, E-mail: meyer@stsci.edu [Florida Institute of Technology, Melbourne, FL 32901 (United States)

    2016-02-20

    The radio galaxy 3C 273 hosts one of the nearest and best-studied powerful quasar jets. Having been imaged repeatedly by the Hubble Space Telescope (HST) over the past twenty years, it was chosen for an HST program to measure proper motions in the kiloparsec-scale resolved jets of nearby radio-loud active galaxies. The jet in 3C 273 is highly relativistic on sub-parsec scales, with apparent proper motions up to 15c observed by very long baseline interferometry. In contrast, we find that the kiloparsec-scale knots are compatible with being stationary, with a mean speed of −0.2 ± 0.5c over the whole jet. Assuming the knots are packets of moving plasma, an upper limit of 1c implies a bulk Lorentz factor Γ < 2.9. This suggests that the jet has either decelerated significantly by the time it reaches the kiloparsec scale, or that the knots in the jet are standing shock features. The second scenario is incompatible with the inverse Compton off the Cosmic Microwave Background (IC/CMB) model for the X-ray emission of these knots, which requires the knots to be in motion, but IC/CMB is also disfavored in the first scenario due to energetic considerations, in agreement with the recent finding of Meyer and Georganopoulos which ruled out the IC/CMB model for the X-ray emission of 3C 273 via gamma-ray upper limits.

  19. Comparative study of 6 MV and 15 MV treatment plans for large chest wall irradiation

    International Nuclear Information System (INIS)

    Prasana Sarathy, N.; Kothanda Raman, S.; Sen, Dibyendu; Pal, Bipasha

    2007-01-01

    Conventionally, opposed tangential fields are used for the treatment of chest wall irradiation. If the chest wall is treated in the linac, 4 or 6 MV photons will be the energy of choice. It is a welI-established rule that for chest wall separations up to 22 cm, one can use mid-energies, with acceptable volume of hot spots. For larger patient sizes (22 cm and above), mid-energy beams produce hot spots over large volumes. The purpose of this work is to compare plans made with 6 and 15 MV photons, for patients with large chest wall separations. The obvious disadvantage in using high-energy photons for chest wall irradiation is inadequate dose to the skin. But this can be compensated by using a bolus of suitable thickness

  20. Numerical and Experimental Study on Confinement in Y-Shaped Post Wall Branching Waveguide

    Directory of Open Access Journals (Sweden)

    Hiroshi Maeda

    2014-01-01

    Full Text Available Post wall waveguides consist of dielectric or metallic cylinders for microwave around 4 GHz were experimentally and numerically investigated. The structure attracts interests for application of transmission circuit for three-dimensionally integrated planar circuit in millimeter wavelength. In straight waveguide with dielectric cylinders, confinement of microwave is poor, when the post wall was composed of a pair of single row of cylinders. The confinement was improved as increase of rows of post wall. In metallic cylinders, microwave was well confined even when a pair of single row of cylinders composed the waveguide. After confirming confinement of the electromagnetic field, Y-shaped branches of post wall waveguide consisted of dielectric cylinders for microwave were similarly investigated for dielectric rods. The confinement was also improved by increase of post wall up to 3 layers. These results are applicable for fundamental design and fabrication of integrated circuit for microwave and millimeter wave.

  1. A comparison of extension and severity of perfusion, glucose metabolism and wall motion abnormalities in recent myocardial infarction on patients with and without revascularization

    International Nuclear Information System (INIS)

    Gonzalez, P.; Massardo, T.; Coll, C.; Redondo, F.; Jofre, J.; Redondo, F.; Sierralta, P.; Humeres, P.; Yovanovich, J.; Chamorro, H.

    2002-01-01

    Aim: To compare the extension and severity in perfusion, glucose metabolism and contractility abnormalities in recent myocardial infarction, assessed by different imaging modalities, and to evaluate these functional parameters in patients with and without revascularization (REV). Materials and methods: We assessed 49 patients with a first MI (58 ±12 years; 82 % males) using 1) [Tl201] rest SPECT, 2) [Tl201] redistribution (red) SPECT, 3) [F18]FDG SPECT and 4) 2D echocardiograms at a mean of 9.2 days, range: 1-24; 29 (59%) patients had been REV by means of PTCA or CABG and 20 (41%) underwent only medical therapy. All had angiogram. Images were analyzed blindly, employing the same polar map which included 17 segments in the four sets of studies. Both, the number of segments involved and their severity (normal, mild, moderate or markedly abnormal) using a semiquantitative score from 1 to 4 were tabulated. Results: In the total group (n=833 segments), the abnormal segments in echo were 302 (36%), in Tl rest 231 (28%), in Tl red 223 (26%) and in FDG 202 (24%), (p<0.001 echo vs all other). Regarding severity score, the median (s.d.) values were: 2.6 (0.5); 2.9 (0.9); 2.8 (1.2) and 2.9 (1.2), respectively (p<0.01 echo vs all other). In REV patients (n=493), the lesion size was 154 segments (31%), 116 (23%), 112 (23%) and 100 (20%), respectively. In those without REV (n=340) the number of abnormal segments were 148 (44%), 115 (34%), 111 (33%) and 102 (30%) respectively (p<0.004, REV vs no REV). McNemar, Student t tests were used in the comparisons. Conclusion: In recent MI, echo abnormalities were bigger in size (up to 13%) than the perfusion and metabolic defects, but less severe (down to 10%) compared to radionuclide procedures, possibly due to stunning. Non REV patients presented with greater extension (up to 11%) and more severity (up to 22%) than REV ones in any of the imaging modalities, explained by therapy effect. Both, echo and radionuclide techniques appear

  2. A comparison of extension and severity of perfusion, glucose metabolism and wall motion abnormalities in recent myocardial infarction on patients with and without revascularization

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, P [Department of Nuclear Medicine of the University of Chile Clinical Hospital (Chile); Department of Nuclear Medicine of Santa Maria Clinic (Chile); Massardo, T; Coll, C; Redondo, F; Jofre, J; Sierralta,