Stochastic optimal control of cable vibration in plane by using axial support motion
Institute of Scientific and Technical Information of China (English)
Ming Zhao; Wei-Qiu Zhu
2011-01-01
A stochastic optimal control strategy for a slightly sagged cable using support motion in the cable axial direction is proposed. The nonlinear equation of cable motion in plane is derived and reduced to the equations for the first two modes of cable vibration by using the Galerkin method.The partially averaged 10 equation for controlled system energy is further derived by applying the stochastic averaging method for quasi-non-integrable Hamiltonian systems. The dynamical programming equation for the controlled system energy with a performance index is established by applying the stochastic dynamical programming principle and a stochastic optimal control law is obtained through solving the dynamical programming equation. A bilinear controller by using the direct method of Lyapunov is introduced. The comparison between the two controllers shows that the proposed stochastic optimal control strategy is superior to the bilinear control strategy in terms of higher control effectiveness and efficiency.
DEFF Research Database (Denmark)
Zhou, Q.; Nielsen, Søren R.K.; Qu, W.L.
2007-01-01
The paper deals with the control of sub- and superharmonic resonances by means of magnetorheological (MR) dampers of an inclined shallow cable caused by parametric excitation from harmonically varying support points. A mechanical model based on the Dahl hysteretic model is used to describe the...... dynamic property of the MR damper, and the finite difference method is used to discretize the derived governing nonlinear equations of motion of the cable-damper system. Semi-active control strategies are proposed based on the modulated homogeneous friction (SA-1) algorithm and the balance logic (SA-2......) algorithm. Four cases are analysed when the circular frequency O of the support point motion is in the vicinity of 2o1, o1, 2o1/3, and o1/2, o1 being the first in-plane eigenfrequency of the cable. The vibration reduction ability of the MR damper is compared with that of the viscous damper optimally tuned...
Thermophoretic motion of bodies with axial symmetry
International Nuclear Information System (INIS)
Thermophoresis of axially symmetric bodies is investigated to first order in the Knudsen number, K n. The study is made in the limit where the typical length of the immersed body is small compared with the mean free path. It is shown that in this case, in contrast to what is the case for spherical bodies, the arising thermal force on the body is not in general anti-parallel to the temperature gradient. It is also shown that the gas exerts a torque on the body, which in magnitude and direction depends on the body geometry. Equations of motion describing the body movement are derived. Stationary solutions are studied
An Impact Motion Generation Support Software
Tsujita, Teppei; Konno, Atsushi; Nomura, Yuki; Komizunai, Shunsuke; Ayaz, Yasar; Uchiyama, Masaru
2010-01-01
The detail of impact motion generation support software is presented in this paper. The developed software supports impact motion design with OpenHRP or OpenHRP3. A preliminary impact motion experiment is performed by a humanoid robot and the analyses of its result are presented. The analysis reveals that the designed motion is not robust against error in the position of the nail since the timing of pulling up the hammer is defined in the designed motion in advance. Therefore, ...
An AFM-based methodology for measuring axial and radial error motions of spindles
International Nuclear Information System (INIS)
This paper presents a novel atomic force microscopy (AFM)-based methodology for measurement of axial and radial error motions of a high precision spindle. Based on a modified commercial AFM system, the AFM tip is employed as a cutting tool by which nano-grooves are scratched on a flat surface with the rotation of the spindle. By extracting the radial motion data of the spindle from the scratched nano-grooves, the radial error motion of the spindle can be calculated after subtracting the tilting errors from the original measurement data. Through recording the variation of the PZT displacement in the Z direction in AFM tapping mode during the spindle rotation, the axial error motion of the spindle can be obtained. Moreover the effects of the nano-scratching parameters on the scratched grooves, the tilting error removal method for both conditions and the method of data extraction from the scratched groove depth are studied in detail. The axial error motion of 124 nm and the radial error motion of 279 nm of a commercial high precision air bearing spindle are achieved by this novel method, which are comparable with the values provided by the manufacturer, verifying this method. This approach does not need an expensive standard part as in most conventional measurement approaches. Moreover, the axial and radial error motions of the spindle can both be obtained, indicating that this is a potential means of measuring the error motions of the high precision moving parts of ultra-precision machine tools in the future. (paper)
Chaotic motion in axially symmetric potentials with oblate quadrupole deformation
International Nuclear Information System (INIS)
By computing the Poincare's surfaces of section and Lyapunov exponents, we study the effect of introducing an oblate quadrupole in the dynamics associated with two generic spherical potentials of physical interest: the central monopole and the isotropic harmonic oscillator. In the former case we find saddle points in the effective potential, in contrast to the statements presented by Gueron and Letelier in [E. Gueron, P.S. Letelier, Phys. Rev. E 63 (2001) 035201]. The results we show in the second case have application in nuclear or atomic physics. In particular, we find values of oblate deformation leading to a disappearance of shell structure in the single-particle spectrum. -- Highlights: → We find chaotic motion around a monopole with oblate quadrupole deformation. → This corrects the statements introduced in [E. Gueron, P.S. Letelier, Phys. Rev. E 63 (2001) 035201]. → We present an alternative model for the potential due to an oblate deformed nuclei. → This leads to stochastic regions in the phase space of classical orbits. → It suggests that the shell structure of single-particle spectrum tends to disappear.
Chaotic motion in axially symmetric potentials with oblate quadrupole deformation
Energy Technology Data Exchange (ETDEWEB)
Letelier, Patricio S. [Departamento de Matematica Aplicada, IMECC, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil); Ramos-Caro, Javier, E-mail: javier@ime.unicamp.br [Departamento de Matematica Aplicada, IMECC, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil); Lopez-Suspes, Framsol, E-mail: framsol@gmail.com [Facultad de Telecomunicaciones, Universidad Santo Tomas and Escuela de Fisica, Universidad Industrial de Santander, Bucaramanga (Colombia)
2011-10-03
By computing the Poincare's surfaces of section and Lyapunov exponents, we study the effect of introducing an oblate quadrupole in the dynamics associated with two generic spherical potentials of physical interest: the central monopole and the isotropic harmonic oscillator. In the former case we find saddle points in the effective potential, in contrast to the statements presented by Gueron and Letelier in [E. Gueron, P.S. Letelier, Phys. Rev. E 63 (2001) 035201]. The results we show in the second case have application in nuclear or atomic physics. In particular, we find values of oblate deformation leading to a disappearance of shell structure in the single-particle spectrum. -- Highlights: → We find chaotic motion around a monopole with oblate quadrupole deformation. → This corrects the statements introduced in [E. Gueron, P.S. Letelier, Phys. Rev. E 63 (2001) 035201]. → We present an alternative model for the potential due to an oblate deformed nuclei. → This leads to stochastic regions in the phase space of classical orbits. → It suggests that the shell structure of single-particle spectrum tends to disappear.
Mechanical axial flow blood pump to support cavopulmonary circulation.
Throckmorton, A L; Kapadia, J; Madduri, D
2008-11-01
We are developing a collapsible, percutaneously inserted, axial flow blood pump to support the cavopulmonary circulation in infants with a failing single ventricle physiology. An initial design of the impeller for this axial flow blood pump was performed using computational fluid dynamics analysis, including pressure-flow characteristics, scalar stress estimations, blood damage indices, and fluid force predictions. A plastic prototype was constructed for hydraulic performance testing, and these experimental results were compared with the numerical predictions. The numerical predictions and experimental findings of the pump performance demonstrated a pressure generation of 2-16 mm Hg for 50-750 ml/min over 5,500-7,500 RPM with deviation found at lower rotational speeds. The axial fluid forces remained below 0.1 N, and the radial fluid forces were determined to be virtually zero due to the centered impeller case. The scalar stress levels remained below 250 Pa for all operating conditions. Blood damage analysis yielded a mean residence time of the released particles, which was found to be less than 0.4 seconds for both flow rates that were examined, and a maximum residence time was determined to be less than 0.8 seconds. We are in the process of designing a cage with hydrodynamically shaped filament blades to act as a diffuser and optimizing the impeller blade shape to reduce the flow vorticity at the pump outlet. This blood pump will improve the clinical treatment of patients with failing Fontan physiology and provide a unique catheter-based therapeutic approach as a bridge to recovery or transplantation. PMID:19089799
Natural frequencies of axial-torsional coupled motion in springs and composite bars
Howson, W. P.; Rafezy, B.
2011-07-01
The natural frequencies corresponding to axial-torsional (extension-twist) coupled motion of a helical spring, or the corresponding motion induced through material coupling in a composite bar, are considered using an equivalent continuum approach. Closed form solution of the governing differential equations leads either to an exact dynamic stiffness matrix or to a number of exact relationships between the natural frequencies corresponding to coupled and uncoupled motion. The latter relationships both guarantee that the Wittrick-Williams root finding algorithm can still be used to converge on any required natural frequency, despite any lack of reciprocity arising from differential coupling, and for the case of symmetric material coupling coefficients, enable their value to be determined precisely from experimental results. A number of examples are then given to confirm the accuracy of the proposed theory and to indicate its range of application.
International Nuclear Information System (INIS)
This paper describes a concurrent measurement of spindle radial, axial and angular motions using concentric circle grating and phase modulation interferometers. In the measurement, a concentric circle grating with fine pitch is the reference artifact. A frequency modulated laser diode is used for the light source of the phase modulation interferometers. The phase modulation interferometers, which consist of three Michelson and three grating interferometers, measure three radial and three axial displacements of the grating. From these six measured displacements, radial, axial and angular motions of a spindle can be determined concurrently. In the paper, a measurement principle, a measurement instrument and experimental results are discussed. Concurrent measurements of spindle radial, axial and angular motions were successfully attained. (paper)
THE STABILITY OF AN AXIALLY ACCELERATING BEAM ON SIMPLE SUPPORTS WITH TORSION SPRINGS
Institute of Scientific and Technical Information of China (English)
Yang Xiaodong; Chen Liqun
2005-01-01
The axially moving beams on simple supports with torsion springs are studied. The general modal functions of the axially moving beam with constant speed have been obtained from the supporting conditions. The contribution of the spring stiffness to the natural frequencies has been numerically investigated. Transverse stability is also studied for axially moving beams on simple supports with torsion springs. The method of multiple scales is applied to the partialdifferential equation governing the transverse parametric vibration. The stability boundary is derived from the solvability condition. Instability occurs if the axial speed fluctuation frequency is close to the sum of any two natural frequencies or is two fold natural frequency of the unperturbed system. It can be concluded that the spring stiffness makes both the natural frequencies and the instability regions smaller in the axial speed fluctuation frequency-amplitude plane for given mean axial speed and bending stiffness of the beam.
Characteristics of a magnetic fluid seal and its motion in an axial variable seal gap
Institute of Scientific and Technical Information of China (English)
QIAN Ji-guo; YANG Zhi-yi
2008-01-01
With suitable assumptions a hydrodynamic model for the magnetic fluid motion in an axial variable gap seal was constructed, and the solution to the equations of the model was deduced. The characteristics of a magnetic fluid seal and its motion,including the speed and pressure distribution, and the seal capacity of a magnetic fluid rotating seal were systematically described.The factors affecting seal capacity and ways to improve seal capacity based on the hydrodynamic model are discussed. The basic condition for dynamic seal availability is presented. The rotating speed and radius of the shafts should be decreased. The work can provide proof of a seal design or suggest ways to improve the seal capacity of magnetic fluid seals.
Directory of Open Access Journals (Sweden)
Harman Melinda K
2012-10-01
internal rotation during mid-flexion. Knees with femoral-tibial rotational mismatch had significantly lower total axial rotation compared to knees with nominal alignment. Conclusions Maintaining relative rotational mismatch within ±5° during TKR provided for controlled knee axial rotation during flexion. TKR with rotational alignment outside of defined surgical norms, with either positive or negative mismatch, experienced measurable kinematic differences and presented different patterns of axial rotation motions during passive knee flexion compared to TKR with nominal mismatch. These findings support previous studies linking prosthesis rotational alignment with inferior clinical and functional outcomes. Trial Registration Clinical Trials NCT01022099
Wang, Song; Song, Jian; Liao, Zhenhua; Feng, Pingfa; Liu, Weiqiang
2016-06-01
The wear behaviors of a ball-on-socket (UHMWPE-on-Ti6Al4V) artificial cervical disc were studied with 1.5MC (million cycles) wear simulation under single flexion/extension and axial rotation motion and their composite motion. The wear rates, wear traces, and contact stress were analyzed and contrasted based on mass loss, optical microscopy and SEM as well as 3D profilometer, and ANSYS software, respectively. A much higher wear rate and more severe wear scars appeared under multi-directional motion. Flexion/extension motion of 7.5° lead to more severe wear than that under axial rotation motion of 4°. The above results were closely related to the contact compression stress and shear stress. The wear surface in FE motion showed typical linear wear scratches while revealing obvious arc-shaped wear tracks in AR motion. However, the central zone of both ball and socket components revealed more severe wear tracks than that in the edge zone under these two different motions. The dominant wear mechanism was plowing/scratching and abrasive wear as well as a little oxidation wear for the titanium socket while it was scratching damage with adhesive wear and fatigue wear due to plastic deformation under cyclic load and motion profiles for the UHMWPE ball. PMID:27040218
International Nuclear Information System (INIS)
In this paper, the ratio of the mass coefficients for the γ-vibrational and rotational motion for the well deformed axially symmetric nuclei is calculated. Calculations are performed based on the cranking model approach. The results obtained show that the microscopic model based on the Woods–Saxon nuclear mean field potential and the pairing forces with a constant strength coefficient qualitatively explain the existing experimental data on the ratio of the mass coefficients. (author)
Vector modeling and track simulation in axial turn-milling motion
Institute of Scientific and Technical Information of China (English)
JIANG Zeng-hui; JIA Chun-de
2005-01-01
Through vector analysis the kinetic vector model is built in a machining cylinder surface through axial turn-milling. When building a kinetic vector model in the machining field, machining through axial turn-milling and using equilateral triangles and square prism surfaces, the kinetic vector model is given any equilateral polygon prismic surface. Kinetic tracks are simulated through these kinetic models respectively, thus it can be seen that the axial turn-milling is a very effective method in manufacturing any equilateral, polygon, prismic surface.
Hillmann, Dierck; Bonin, Tim; Lührs, Christian; Franke, Gesa; Hagen-Eggert, Martin; Koch, Peter; Hüttmann, Gereon
2012-03-12
Swept-source optical coherence tomography (SS-OCT) is sensitive to sample motion during the wavelength sweep, which leads to image blurring and image artifacts. In line-field and full-field SS-OCT parallelization is achieved by using a line or area detector, respectively. Thus, approximately 1000 lines or images at different wavenumbers are acquired. The sweep duration is identically with the acquisition time of a complete B-scan or volume, rendering parallel SS-OCT more sensitive to motion artifacts than scanning OCT. The effect of axial motion on the measured spectra is similar to the effect of non-balanced group velocity dispersion (GVD) in the interferometer arms. It causes the apparent optical path lengths in the sample arm to vary with the wavenumber. Here we propose the cross-correlation of sub-bandwidth reconstructions (CCSBR) as a new algorithm that is capable of detecting and correcting the artifacts induced by axial motion in line-field or full-field SS-OCT as well as GVD mismatch in any Fourier-domain OCT (FD-OCT) setup. By cross-correlating images which were reconstructed from a limited spectral range of the interference signal, a phase error is determined which is used to correct the spectral modulation prior to the calculation of the A-scans. Performance of the algorithm is demonstrated on in vivo full-field SS-OCT images of skin and scanning FD-OCT of skin and retina. PMID:22418560
Energy Technology Data Exchange (ETDEWEB)
Balakrishnan, S; Rahnejat, H [Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough (United Kingdom)
2005-03-07
The paper describes the combined axial, lateral and tilting motions of piston within the confine of cylinder bore, with sliding and normally approaching and separating contacts between the piston skirt and the cylinder wall on both the major and minor thrust sides. The methodology developed undertakes combined solution for inertial dynamics of the piston, together with transient elastohydrodynamic analysis of both contacts. It also includes important practical features of the contacting surfaces, such as the axial form relieving of the piston skirt profile. The space-time solver uses Newmark {beta}-type time marching integrator, as well as the effective influence Newton-Raphson method for space-domain solution of the elastohydrodynamic conjunctions in each step of time. This approach, not hitherto reported for this type of conforming contacts yields accurate predictions of lubricant film thickness and pressure distribution within computationally acceptable times, given the inclusion of level of detail in the model.
Non-Parametric Bayesian Human Motion Recognition Using a Single MEMS Tri-Axial Accelerometer
Ejaz Ahmed, M.; Ju Bin Song
2012-01-01
In this paper, we propose a non-parametric clustering method to recognize the number of human motions using features which are obtained from a single microelectromechanical system (MEMS) accelerometer. Since the number of human motions under consideration is not known a priori and because of the unsupervised nature of the proposed technique, there is no need to collect training data for the human motions. The infinite Gaussian mixture model (IGMM) and collapsed Gibbs sampler are adopted to cl...
Non-Parametric Bayesian Human Motion Recognition Using a Single MEMS Tri-Axial Accelerometer
Directory of Open Access Journals (Sweden)
M. Ejaz Ahmed
2012-09-01
Full Text Available In this paper, we propose a non-parametric clustering method to recognize the number of human motions using features which are obtained from a single microelectromechanical system (MEMS accelerometer. Since the number of human motions under consideration is not known a priori and because of the unsupervised nature of the proposed technique, there is no need to collect training data for the human motions. The infinite Gaussian mixture model (IGMM and collapsed Gibbs sampler are adopted to cluster the human motions using extracted features. From the experimental results, we show that the unanticipated human motions are detected and recognized with significant accuracy, as compared with the parametric Fuzzy C-Mean (FCM technique, the unsupervised K-means algorithm, and the non-parametric mean-shift method.
Non-parametric Bayesian human motion recognition using a single MEMS tri-axial accelerometer.
Ahmed, M Ejaz; Song, Ju Bin
2012-01-01
In this paper, we propose a non-parametric clustering method to recognize the number of human motions using features which are obtained from a single microelectromechanical system (MEMS) accelerometer. Since the number of human motions under consideration is not known a priori and because of the unsupervised nature of the proposed technique, there is no need to collect training data for the human motions. The infinite Gaussian mixture model (IGMM) and collapsed Gibbs sampler are adopted to cluster the human motions using extracted features. From the experimental results, we show that the unanticipated human motions are detected and recognized with significant accuracy, as compared with the parametric Fuzzy C-Mean (FCM) technique, the unsupervised K-means algorithm, and the non-parametric mean-shift method. PMID:23201992
Axial tomographic scanner having means for supporting X-ray source cables
International Nuclear Information System (INIS)
An axial tomographic scanner is described which has means for supporting a plurality of cables leading to the X-ray source, including a yoke upon which the X-ray source is mounted, first bracket means mounted on the yoke adjacent the X-ray source for restraining cable movement, second bracket means mounted on the yoke remote from the X-ray source for restraining cable movement, and means disposed between the first and second bracket means for maintaining the cables passing therethrough in a gradual arc while preventing undue flexing of the cables and undesirable movement of the cables into an interfering position with other components of the axial tomographic scanner
The most general axially symmetric electrovac spacetime admitting separable equations of motion
International Nuclear Information System (INIS)
We obtain the most general solution of the Einstein electro-vacuum equation for the stationary axially symmetric spacetime in which the Hamilton-Jacobi and Klein-Gordon equations are separable. The most remarkable feature of the solution is its invariance under the duality transformation involving mass and NUT parameter, and the radial and angle coordinates. It is the general solution for a rotating (gravitational dyon) particle which is endowed with both gravitoelectric and gravitomagnetic charges, and a duality transformation exists from one to the other. It also happens to be a transform of the Kerr-NUT solution. Like the Kerr family, it is also possible to make this solution radiating which asymptotically conforms to the Vaidya null radiation
Axial motion of collector plasma in a relativistic backward wave oscillator
Xiao, Renzhen; Chen, Changhua; Deng, Yuqun; Cao, Yibing; Sun, Jun; Li, Jiawei
2016-06-01
In this paper, it is proposed that plasma formed at the collector may drift back to the cathode and cause pulse shortening of the relativistic backward wave oscillator. Theoretical analysis shows that the axial drift velocity of plasma ions can be up to 5 mm/ns due to the presence of space charge potential provided by an intense relativistic electron beam. Particle-in-cell simulations indicate that the plasma electrons are initially trapped around the collector surface. With the accumulation of the plasma ions, a large electrostatic field forms and drives the plasma electrons to overcome the space charge potential and enter the beam-wave interaction region along the magnetic field lines. As a result, the beam current modulation is disturbed and the output microwave power falls rapidly. The plasma ions move in the beam-wave interaction region with an average axial velocity of 5-8 mm/ns. After the plasma ions reach the diode region, the emitted current at the cathode rises due to the charge neutralizations by the ions. The impedance collapse leads to further decrease of the microwave power. In experiments, when the diode voltage and beam current were 850 kV and 9.2 kA, and the collector radius was 2.15 cm, the output microwave power was 2.4 GW with a pulse width of less than 20 ns. The ion drift velocity was estimated to be about 5 mm/ns. After an improved collector with 3.35 cm radius was adopted, the pulse width was prolonged to more than 30 ns.
A rotational and axial motion system load frame insert for in situ high energy x-ray studies
International Nuclear Information System (INIS)
High energy x-ray characterization methods hold great potential for gaining insight into the behavior of materials and providing comparison datasets for the validation and development of mesoscale modeling tools. A suite of techniques have been developed by the x-ray community for characterizing the 3D structure and micromechanical state of polycrystalline materials; however, combining these techniques with in situ mechanical testing under well characterized and controlled boundary conditions has been challenging due to experimental design requirements, which demand new high-precision hardware as well as access to high-energy x-ray beamlines. We describe the design and performance of a load frame insert with a rotational and axial motion system that has been developed to meet these requirements. An example dataset from a deforming titanium alloy demonstrates the new capability
Effect of axial loads on implant-supported partial fixed prostheses by strain gauge analysis
Directory of Open Access Journals (Sweden)
Luis Gustavo Oliveira de Vasconcellos
2011-12-01
Full Text Available OBJECTIVES: The present study used strain gauge analysis to perform an in vitro evaluation of the effect of axial loading on 3 elements of implant-supported partial fixed prostheses, varying the type of prosthetic cylinder and the loading points. MATERIAL AND METHODS: Three internal hexagon implants were linearly embedded in a polyurethane block. Microunit abutments were connected to the implants applying a torque of 20 Ncm, and prefabricated Co-Cr cylinders and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n=5. Four strain gauges (SG were bonded onto the surface of the block tangentially to the implants, SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments with a 10 Ncm torque and an axial load of 30 kg was applied at five predetermined points (A, B, C, D, E. The data obtained from the strain gauge analyses were analyzed statistically by RM ANOVA and Tukey's test, with a level of significance of p<0.05. RESULTS: There was a significant difference for the loading point (p=0.0001, with point B generating the smallest microdeformation (239.49 µε and point D the highest (442.77 µε. No significant difference was found for the cylinder type (p=0.748. CONCLUSIONS: It was concluded that the type of cylinder did not affect in the magnitude of microdeformation, but the axial loading location influenced this magnitude.
Vibrations of axially moving strings with in-plane oscillating supports
DEFF Research Database (Denmark)
Fuglede, Niels; Thomsen, Jon Juel
uniform, heavy string moving at subcritical speed with prescribed endpoint motion, and ignoring longitudinal inertia, one obtains a continuous, nonlinear, gyroscopic, parametrically and externally excited system. By employing a single-mode approximation, using velocity dependent mode shapes, the system...... response is approximated using the method of multiple scales. Vibrations from support oscillations characteristic of roller chain drives are investigated. Conclusions about critical values for chain drive parameters such as pretension and meshing frequency are sought and identified....
Schibilsky, David; Lenglinger, Matthias; Avci-Adali, Meltem; Haller, Christoph; Walker, Tobias; Wendel, Hans Peter; Schlensak, Christian
2015-08-01
The hemocompatible properties of rotary blood pumps commonly used in mechanical circulatory support (MCS) are widely unknown regarding specific biocompatibility profiles of different pump technologies. Therefore, we analyzed the hemocompatibility indicating markers of an axial flow and a magnetically levitated centrifugal device within an in vitro mock loop. The HeartMate II (HM II; n = 3) device and a CentriMag (CM; n = 3) adult pump were investigated in a human whole blood mock loop for 360 min using the MCS devices as a driving component. Blood samples were analyzed by enzyme-linked immunosorbent assay for markers of coagulation, complement system, and inflammatory response. There was a time-dependent activation of the coagulation (thrombin-antithrombin complexes [TAT]), complement (SC5b-9), and inflammation system (polymorphonuclear [PMN] elastase) in both groups. The mean value of TAT (CM: 4.0 μg/L vs. 29.4 μg/L, P centrifugal CM device showed significantly lower activation of coagulation and inflammation than that of the HM II axial flow pump. Both HM II and CM have demonstrated an acceptable hemocompatibility profile in patients. However, there is a great opportunity to gain a clinical benefit by developing techniques to lower the blood surface interaction within both pump technologies and a magnetically levitated centrifugal pump design might be superior. PMID:26234452
International Nuclear Information System (INIS)
The new in-pin fuel motion model CAMDYN (Cavity Material Dynamics) describes the axial motion of both partially and fully molten fuel inside the pin of a fast breeder reactor during accident conditions. The motion of the two types of molten fuel and the imbedded fission gas bubbles is treated both before and after cladding failure. The basic modelling approach consists of the treatment of two one-dimensional flows which are coupled by interaction terms. Each of these flows is treated compressively and with axially variable flow cross sections. The mass and energy equations of both fields are solved explicitly using upwind differencing on a fixed Eulerian grid. The two momentum equations are solved simultaneously, using the convective momentum fluxes of the previous timestep. Both partially and fully molten fuel can move axially into a central hole extending to the plenum in the case of certain hollow pellet designs. The fuel temperature calculation includes the determination of a radial temperature profile. A simple conduction freezing model is included. After cladding failure, ejection into the coolant channel is modeled
Bordag, L A; Froehner, M; Myrnyy, V
2003-01-01
We analyze the stability of a cylindrical Couette flow under the imposition of a weak axial flow in case of a very short cylinder with a narrow annulus gap. We consider an incompressible viscous fluid which is contained in the narrow gap between two concentric short cylinders, where the inner cylinder rotates with constant angular velocity. The caps of the cylinders have narrow tubes conically tapering to super narrow slits which allow for an axial flow along the surface of the inner cylinder. The approximated solution for the Couette flow for short cylinders was found and used for the stability analysis instead of the exact but bulky solution. The sensitivity of the Couette flow to general small perturbations and to the weak axial flow was studied. We demonstrate that perturbations coming from the axial flow cause the propagation of dispersive waves in the Taylor-Couette flow. The coexistence of a rotation and of an axial flow requires to study in addition to the energy and the angular momentum also the heli...
Transverse vibration characteristics of axially moving viscoelastic plate
Institute of Scientific and Technical Information of China (English)
ZHOU Yin-feng; WANG Zhong-min
2007-01-01
The dynamic characteristics and stability of axially moving viscoelastic rectangular thin plate are investigated. Based on the two dimensional viscoelastic differential constitutive relation, the differential equations of motion of the axially moving viscoelastic plate are established. Dimensionless complex frequencies of an axially moving viscoelastic plate with four edges simply supported, two opposite edges simply supported and other two edges clamped are calculated by the differential quadrature method. The effects of the aspect ratio, moving speed and dimensionless delay time of the material on the transverse vibration and stability of the axially moving viscoelastic plate are analyzed.
International Nuclear Information System (INIS)
We have developed an algorithm for real-time detection and complete correction of the patient motion effects during single photon emission computed tomography. The algorithm is based on a linear prediction filter (LPC). The new prediction of projection data algorithm (PPDA) detects most motions-such as those of the head, legs, and hands-using comparison of the predicted and measured frame data. When the data acquisition for a specific frame is completed, the accuracy of the acquired data is evaluated by the PPDA. If patient motion is detected, the scanning procedure is stopped. After the patient rests in his or her true position, data acquisition is repeated only for the corrupted frame and the scanning procedure is continued. Various experimental data were used to validate the motion detection algorithm; on the whole, the proposed method was tested with approximately 100 test cases. The PPDA shows promising results. Using the PPDA enables us to prevent the scanner from collecting disturbed data during the scan and replaces them with motion-free data by real-time rescanning for the corrupted frames. As a result, the effects of patient motion is corrected in real time. (author)
Directory of Open Access Journals (Sweden)
Zhiwei WANG
2016-06-01
Full Text Available At present, the research on static and dynamic characteristics of hydrostatic supports depend on the form and structure of the restrictor, which are mainly focused on the influences of recess shape, bearing structure, bearing surface roughness, lubricant and elastic deformations of the bearing. There are few studies on the thermal effect of hydrostatic supports and static and dynamic characteristics of hydrostatic guideways. The research on motion errors of hydrostatic supports is primarily based on the static equilibrium of the moving part. The effects of the motion speed of the moving part and structural deformation on the motion errors are not considered. Finally, the research prospects from the standardization, modularization and industrialization of hydrostatic supports, thermal effect of hydrostatic bearing, the static and dynamic characteristics of hydrostatic guideways and motion errors of hydrostatic supports under operating conditions are concluded.
Mills Chris; Ayres Bessie; Scurr Joanna
2015-01-01
The buoyant forces of water during aquatic exercise may provide a form of ‘natural’ breast support and help to minimise breast motion and alleviate exercise induced breast pain. Six larger-breasted females performed standing vertical land and water-based jumps, whilst wearing three breast support conditions. Underwater video cameras recorded the motion of the trunk and right breast. Trunk and relative breast kinematics were calculated as well as exercised induced breast pain scores. Key resul...
Graybill, George
2007-01-01
Take the mystery out of motion. Our resource gives you everything you need to teach young scientists about motion. Students will learn about linear, accelerating, rotating and oscillating motion, and how these relate to everyday life - and even the solar system. Measuring and graphing motion is easy, and the concepts of speed, velocity and acceleration are clearly explained. Reading passages, comprehension questions, color mini posters and lots of hands-on activities all help teach and reinforce key concepts. Vocabulary and language are simplified in our resource to make them accessible to str
Dynamic stability of simply supported composite cylindrical shells under partial axial loading
Dey, Tanish; Ramachandra, L. S.
2015-09-01
The parametric vibration of a simply supported composite circular cylindrical shell under periodic partial edge loadings is discussed in this article. Donnell's nonlinear shallow shell theory considering first order shear deformation theory is used to model the shell. The applied partial edge loading is represented in terms of a Fourier series and stress distributions within the cylindrical shell are determined by prebuckling analysis. The governing equations of the dynamic instability of shells are derived in terms of displacements (u-v-w) and rotations (φx, φθ). Employing the Galerkin and Bolotin methods the dynamic instability regions are computed. Using the expression for the stress function derived in this paper, the pre-buckling stresses in the cylindrical shell due to partial loading can be calculated explicitly. Numerical results are presented to show the influence of radius-to-thickness ratio, different partial edge loading distributions and shear deformation on the dynamic instability regions. The linear and nonlinear responses in the stable and unstable regions are presented to bring out the characteristic features of the dynamic instability regions, such as the existence of beats, its dependence on forcing frequency and effect of nonlinearity on the response. The effect of dynamic load amplitude on the nonlinear response is also studied. It is found that for higher values of dynamic loading, the shell exhibits chaotic behavior.
RESEARCH NOTES On the support of super-Brownian motion with super-Brownian immigration
Institute of Scientific and Technical Information of China (English)
洪文明; 钟惠芳
2001-01-01
The support properties of the super Brownian motion with random immigration Xρ1 are considered,where the immigration rate is governed by the trajectory of another super-Brownian motion ρ. When both the initial state Xρo of the process and the immigration rate process ρo are of finite measure and with compact supports, the probability of the support of the process Xρi dominated by a ball is given by the solutions of a singular elliptic boundary value problem.
Multi-frequency response of a cylinder subjected to vortex shedding and support motions
Energy Technology Data Exchange (ETDEWEB)
Vikestad, Kyrre
1998-12-31
This thesis deals with an experimental investigation of vortex induced vibrations of a circular cylinder. The purpose of the experiment was to identify the influence from a controlled disturbance of the cylinder motions on the response caused by vortex shedding. The cylinder investigated is 2 m long and the diameter is 10 cm. The cylinder is elastically mounted in an apparatus using springs, where the foundation of one of the springs can have a harmonic motion. The apparatus is placed on a carriage in a 25 m long towing tank. Towing velocities are varied between 0.140 m/s and 0.655 m/s corresponding to reduced velocity range from 2.8 to 13.2. The still water natural frequency is 0.497 Hz, and the natural frequency in air is 0.634 Hz. The cylinder is only able to oscillate in the cross-flow direction. The support motion frequency was varied between 0.26 Hz and 1.01 Hz, and the force motion amplitude was varied using 2, 4 and 6 cm support amplitudes. Three sets of experiments were carried out: (1) Still water oscillations due to harmonic support motion excitation, support amplitude and frequencies varied, (2) Towing tests with no support motion, the velocity is varied, (3) Combined excitation: Towing tests with support motion. All possible combinations of experiments (1) and (2) are carried out. The two first experiments provide reference values for the combined excitation experiments and for verification purposes. The results reveal the ability of the external disturbance to influence the vortex shedding process both regarding frequency and the resulting response amplitudes. Results for added mass, in-line drag and damping are also obtained. The work may be of use in deep water floating petroleum production. 81 refs., 73 figs., 6 tabs.
Mills, Chris; Ayres, Bessie; Scurr, Joanna
2015-06-27
The buoyant forces of water during aquatic exercise may provide a form of 'natural' breast support and help to minimise breast motion and alleviate exercise induced breast pain. Six larger-breasted females performed standing vertical land and water-based jumps, whilst wearing three breast support conditions. Underwater video cameras recorded the motion of the trunk and right breast. Trunk and relative breast kinematics were calculated as well as exercised induced breast pain scores. Key results showed that the swimsuit and sports bra were able to significantly reduce the superioinferior breast range of motion by 0.04 and 0.05 m, respectively, and peak velocity by 0.23 and 0.33 m/s, respectively, during land-based jumping when compared to the bare-breasted condition, but were ineffective at reducing breast kinematics during water-based jumping. Furthermore, the magnitude of the swimsuit superioinferior breast range of motion during water-based jumping was significantly greater than land-based jumping (0.13 m and 0.06 m), yet there were no significant differences in exercise induced breast pain, thus contradicting previously published relationships between these parameters on land. Furthermore, the addition of an external breast support garment was able to reduce breast kinematics on land but not in water, suggesting the swimsuit and sports bras were ineffective and improvements in swimwear breast support garments may help to reduce excessive breast motion during aqua aerobic jumping exercises. PMID:26240648
Directory of Open Access Journals (Sweden)
Mills Chris
2015-06-01
Full Text Available The buoyant forces of water during aquatic exercise may provide a form of ‘natural’ breast support and help to minimise breast motion and alleviate exercise induced breast pain. Six larger-breasted females performed standing vertical land and water-based jumps, whilst wearing three breast support conditions. Underwater video cameras recorded the motion of the trunk and right breast. Trunk and relative breast kinematics were calculated as well as exercised induced breast pain scores. Key results showed that the swimsuit and sports bra were able to significantly reduce the superioinferior breast range of motion by 0.04 and 0.05 m, respectively, and peak velocity by 0.23 and 0.33 m/s, respectively, during land-based jumping when compared to the bare-breasted condition, but were ineffective at reducing breast kinematics during water-based jumping. Furthermore, the magnitude of the swimsuit superioinferior breast range of motion during water-based jumping was significantly greater than land-based jumping (0.13 m and 0.06 m, yet there were no significant differences in exercise induced breast pain, thus contradicting previously published relationships between these parameters on land. Furthermore, the addition of an external breast support garment was able to reduce breast kinematics on land but not in water, suggesting the swimsuit and sports bras were ineffective and improvements in swimwear breast support garments may help to reduce excessive breast motion during aqua aerobic jumping exercises.
Ayık, Hatice Müjde; Griffin, Michael J
2015-01-01
While walking on a treadmill, 20 subjects experienced lateral oscillations: frequencies from 0.5 to 2 Hz and velocities from 0.05 to 0.16 m s(- 1) rms. Postural stability was indicated by ratings of 'discomfort or difficulty in walking', the movement of the centre of pressure beneath the feet and lateral forces applied to a hand support. Hand support improved postural stability with all frequencies and all velocities of oscillatory motion: the lateral velocity of the centre of pressure reduced by 30-50% when using support throughout motion, by 20-30% when instructed to use the support only when required and by 15% during normal walking without oscillation. Improvements in stability, and the forces applied to the hand support, were independent of support height when used continuously throughout motion. When support was used only when required, subjects preferred to hold it 118-134 cm above the surface supporting the feet. PMID:25331636
Energy Technology Data Exchange (ETDEWEB)
Bezler, P.; Hartzman, M.; Reich, M.
1980-08-01
A set of benchmark problems and solutions have been developed for verifying the adequacy of computer programs used for dynamic analysis and design of nuclear piping systems by the Response Spectrum Method. The problems range from simple to complex configurations which are assumed to experience linear elastic behavior. The dynamic loading is represented by uniform support motion, assumed to be induced by seismic excitation in three spatial directions. The solutions consist of frequencies, participation factors, nodal displacement components and internal force and moment components. Solutions to associated anchor point motion static problems are not included.
Non-linear effects in the support motion of an elastically mounted slider crank mechanism
Davidson, I.
1983-01-01
A study is made of an in-line slider crank mechanism in which the sliding mass is elastically supported. The ratio of crank length to connecting rod length is not assumed small and relatively large displacements of the support are allowed. Ordinary and parametric non-linear terms are thus retained in the equations of motion. It is shown that the presence of parametric terms gives rise to additional conditions for resonance in the support motion. Approximate solutions are obtained for the fundamental and half subharmonic steady state responses and the effect of the non-linear and parametric terms examined. The stability of the steady state responses is considered and it is shown that instability is associated with a negative slope of the amplitude frequency characteristic.
Influence of earthquake ground motion incoherency on multi-support structures
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
A linear response history analysis method is used to determine the influence of three factors: geometric incoherency, wave-passage, and local site characteristics on the response of multi-support structures subjected to differential ground motions. A one-span frame and a reduced model of a 24-span bridge, located in Las Vegas, Nevada are studied, in which the influence of each of the three factors and their combinations are analyzed. It is revealed that the incoherency of earthquake ground motion can have a dramatic influence on structural response by modifying the dynamics response to uniform excitation and inducing pseudo-static response, which does not exist in structures subjected to uniform excitation. The total response when all three sources of ground motion incoherency are included is generally larger than that of uniform excitation.
Directory of Open Access Journals (Sweden)
S. V. Gautier
2013-01-01
Full Text Available The paper describes the first clinical experience in RF of successful application of domestic circulatory support device based on implantable axial pump for two stage heart transplantation. This case demonstrate the effec- tiveness and safety of our device (АВК-Н for a longtime (270 days left ventricular bypass and the ability to perform a successful transplantation of donor,s heart after application of this system.
Singh, S D; Xu, X Y; Pepper, J R; Izgi, C; Treasure, T; Mohiaddin, R H
2016-07-01
Aortic root motion was previously identified as a risk factor for aortic dissection due to increased longitudinal stresses in the ascending aorta. The aim of this study was to investigate the effects of aortic root motion on wall stress and strain in the ascending aorta and evaluate changes before and after implantation of personalised external aortic root support (PEARS). Finite element (FE) models of the aortic root and thoracic aorta were developed using patient-specific geometries reconstructed from pre- and post-PEARS cardiovascular magnetic resonance (CMR) images in three Marfan patients. The wall and PEARS materials were assumed to be isotropic, incompressible and linearly elastic. A static load on the inner wall corresponding to the patients' pulse pressure was applied. Cardiovascular MR cine images were used to quantify aortic root motion, which was imposed at the aortic root boundary of the FE model, with zero-displacement constraints at the distal ends of the aortic branches and descending aorta. Measurements of the systolic downward motion of the aortic root revealed a significant reduction in the axial displacement in all three patients post-PEARS compared with its pre-PEARS counterparts. Higher longitudinal stresses were observed in the ascending aorta when compared with models without the root motion. Implantation of PEARS reduced the longitudinal stresses in the ascending aorta by up to 52%. In contrast, the circumferential stresses at the interface between the supported and unsupported aorta were increase by up to 82%. However, all peak stresses were less than half the known yield stress for the dilated thoracic aorta. PMID:27255604
Dynamic response of successive oscillators running on a suspended beam shaken by support motions
Czech Academy of Sciences Publication Activity Database
Yau, J. D.; Frýba, Ladislav
Beijing : China Railway Publishing House, 2010 - (Fu Xigang; Zhang Jie), s. 808-811 ISBN 978-7-113-11751-1. [International Conference on Railway Engineering ICRE2010. Beijing (CN), 20.08.2010-22.08.2010] Grant ostatní: GAČR(CZ) GA103/08/1340 Institutional research plan: CEZ:AV0Z20710524 Keywords : suspended bridge * support motion * high-speed train Subject RIV: JM - Building Engineering
Chantarojsiri, Teera; Sun, Yujie; Long, Jeffrey R; Chang, Christopher J
2015-06-15
We report the photochemical generation and study of a family of water-soluble iron(IV)-oxo complexes supported by pentapyridine PY5Me2-X ligands (PY5Me2 = 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine; X = CF3, H, Me, or NMe2), in which the oxidative reactivity of these ferryl species correlates with the electronic properties of the axial pyridine ligand. Synthesis of a systematic series of [Fe(II)(L)(PY5Me2-X)](2+) complexes, where L = CH3CN or H2O, and characterizations by several methods, including X-ray crystallography, cyclic voltammetry, and Mössbauer spectroscopy, show that increasing the electron-donating ability of the axial pyridine ligand tracks with less positive Fe(III)/Fe(II) reduction potentials and quadrupole splitting parameters. The Fe(II) precursors are readily oxidized to their Fe(IV)-oxo counterparts using either chemical outer-sphere oxidants such as CAN (ceric ammonium nitrate) or flash-quench photochemical oxidation with [Ru(bpy)3](2+) as a photosensitizer and K2S2O8 as a quencher. The Fe(IV)-oxo complexes are capable of oxidizing the C-H bonds of alkane (4-ethylbenzenesulfonate) and alcohol (benzyl alcohol) substrates via hydrogen atom transfer (HAT) and an olefin (4-styrenesulfonate) substrate by oxygen atom transfer (OAT). The [Fe(IV)(O)(PY5Me2-X)](2+) derivatives with electron-poor axial ligands show faster rates of HAT and OAT compared to their counterparts supported by electron-rich axial donors, but the magnitudes of these differences are relatively modest. PMID:26039655
Effect of PVRC damping with independent support motion response spectrum analysis of piping systems
International Nuclear Information System (INIS)
The Technical Committee for Piping Systems of the Pressure Vessel Research Committee (PVRC) has recommended new damping values to be used in the seismic analyses of piping systems in nuclear power plants. To evaluate the effects of coupling these recommendations with the use of independent support motion analyses methods, two sets of seismic analyses have been carried out for several piping systems. One set based on the use of uniform damping as specified in Regulatory Guide 1.61, the other based on the PVRC recommendations. In each set the analyses were performed using independent support motion time history and response spectrum methods as well as the envelope spectrum method. In the independent response spectrum analyses, 14 response estimates were in fact obtained by considering different combination procedures between the support group contributions and all sequences of combinations between support groups, modes and directions. For each analysis set, the response spectrum results were compared with time history estimates of those results. Comparison tables were then prepared depicting the percentage by which the response spectrum estimates exceeded the time history estimates. By comparing the result tables between both analysis sets, the impact of PVRC damping can be observed. Preliminary results show that the degree of exceedance of the response spectrum estimates based on PVRC damping is less than that based on uniform damping for the same piping problem. Expressed differently the results obtained if ISM methods are coupled with PVRC damping are not as conservative as those obtained using uniform damping
Directory of Open Access Journals (Sweden)
J. R. LI
2016-02-01
Full Text Available Playing an important role in local and national seaport activities, container wharves are susceptible to structural failure and damage during earthquake events. Therefore, factors that affect the seismic response of crane–wharf structures under different types of earthquake ground motions should be elucidated. In this paper, 3D finite element models were established to investigate the differences of natural vibration characteristics between the wharf and crane–wharf structures. The dynamic response of a typical pile-supported wharf structure and the interaction behavior of a crane and wharf structural system under seismic actions of near-field and far-field ground motions were studied by performing numerical simulation and time-history response analysis. Axial force–moment relation curves were adopted to analyze the elastic–plastic limit state of the wharf structure under different ground motions. Results showed that the consideration of the container crane increased the natural vibration period of the pile-supported wharf structure and affected the dynamic characteristics of the structure. Compared with the far-field earthquake ground motion, the nearfield earthquake exerted a more significant impact on the structural dynamic response that controlled the elastic–plastic limit state. With the presence of a crane, the moment and shear force of the pile-top decreased and the location of the extreme value moved down obviously. The findings demonstrated that considering the crane changed the failure mechanism of the wharf structure, and the eccentric effect of the crane may amplify the dynamic response as the peak ground acceleration increases. The results provide reference for the seismic design and the evaluation of the seismic response of container wharves.
Stability and transient motion of a plain journal mounted in flexible damped supports
Kirk, R. G.; Gunter, E. J.
1975-01-01
Results are presented for an extensive study of the influence of damped flexible supports on the stability-threshold speed of a symmetric rotor mounted in nonlinear fluid-film bearings. A stability analysis is conducted by applying the Routh criteria and calculating the damped eigenvalues of the system. Stability maps are given in dimensionless form for a range of support stiffness, damping, and mass ratios. The effect of rotor imbalance on the stability of rotor systems is examined, and it is shown that time transient orbits of shaft and support motions clearly indicate their dynamic behavior for both stable and unstable operating speeds. Simple design criteria are proposed for choosing the support stiffness and damping on the basis of rotor weight and journal clearance to promote optimum stability. It is concluded that the use of a flexible damped support system may increase the stability threshold of a plain journal bearing and that damper supports should promote smoother and quieter machine operation by suppressing oil whirl and attenuating unbalanced rotational forces.
Directory of Open Access Journals (Sweden)
Nicolò Cavalli
2015-01-01
Full Text Available Objectives. The aim of this retrospective study was to assess the incidence and prevalence of peri-implant mucositis and peri-implantitis in patients with a fixed full-arch prosthesis supported by two axial and two tilted implants. Materials and Methods. Sixty-nine patients were included in the study. Each patient received a fixed full-arch prosthesis supported by two mesial axial and two distal tilted implants to rehabilitate the upper arch, the lower arch, or both. Three hundred thirty-six implants for 84 restorations were delivered. Patients were scheduled for follow-up visits every 6 months in the first 2 years and yearly after. At each follow-up visit peri-implant mucositis and peri-implantitis were diagnosed if present. Results. The overall follow-up range was from 12 to 130 months (mean 63,2 months. Three patients presented peri-implantitis. The prevalence of peri-implant mucositis ranged between 0 and 7,14% of patients (5,06% of implants while the prevalence of peri-implantitis varied from 0 to 4,55% of patients (3,81% of implants. Conclusions. The prevalence and incidence of peri-implant mucositis and peri-implantitis are lower than most of the studies in literature. Therefore this kind of rehabilitation could be considered a feasible option, on the condition of adopting a systematic hygienic protocol.
International Nuclear Information System (INIS)
This paper studies the motion of costal, central tendon, and crural parts of the diaphragm during semistatic VC maneuver and to compare this motion with rib cage (RC) and abdominal (Abd) cross-sectional area changes (CAC) and diaphragmatic volume displacement. Diaphragmatic motion was studied with the use of lateral fluoroscopy of the chest in seven healthy volunteers. RC and Abd CAC was measured with the use of respiratory inductive plethysmography. Diaphragmatic volume displacement was measured with fluoroscopy and calculated from RC and Abd CAC with the use of a theoretical analysis described by previous works
International Nuclear Information System (INIS)
Intra-fraction tumor tracking methods can improve radiation delivery during radiotherapy sessions. Image acquisition for tumor tracking and subsequent adjustment of the treatment beam with gating or beam tracking introduces time latency and necessitates predicting the future position of the tumor. This study evaluates the use of multi-dimensional linear adaptive filters and support vector regression to predict the motion of lung tumors tracked at 30 Hz. We expand on the prior work of other groups who have looked at adaptive filters by using a general framework of a multiple-input single-output (MISO) adaptive system that uses multiple correlated signals to predict the motion of a tumor. We compare the performance of these two novel methods to conventional methods like linear regression and single-input, single-output adaptive filters. At 400 ms latency the average root-mean-square-errors (RMSEs) for the 14 treatment sessions studied using no prediction, linear regression, single-output adaptive filter, MISO and support vector regression are 2.58, 1.60, 1.58, 1.71 and 1.26 mm, respectively. At 1 s, the RMSEs are 4.40, 2.61, 3.34, 2.66 and 1.93 mm, respectively. We find that support vector regression most accurately predicts the future tumor position of the methods studied and can provide a RMSE of less than 2 mm at 1 s latency. Also, a multi-dimensional adaptive filter framework provides improved performance over single-dimension adaptive filters. Work is underway to combine these two frameworks to improve performance.
Energy Technology Data Exchange (ETDEWEB)
Rodgers, A
2008-01-16
In this report we describe the data sets used to evaluate ground motion hazards in Las Vegas from nuclear tests at the Nevada Test Site. This analysis is presented in Rodgers et al. (2005, 2006) and includes 13 nuclear explosions recorded at the John Blume and Associates network, the Little Skull Mountain earthquake and a temporary deployment of broadband station in Las Vegas. The data are available in SAC format on CD-ROM as an appendix to this report.
System identification modelling of ship manoeuvring motion based onε- support vector regression
Institute of Scientific and Technical Information of China (English)
王雪刚; 邹早建; 侯先瑞; 徐锋
2015-01-01
Based on theε-support vector regression, three modelling methods for the ship manoeuvring motion, i.e., the white-box modelling, the grey-box modelling and the black-box modelling, are investigated. Theoo10/10,oo20/20 zigzag tests and the o35 turning circle manoeuvre are simulated. Part of the simulation data for theoo20/20 zigzag test are used to train the support vectors, and the trained support vector machine is used to predict the wholeoo20/20 zigzag test. Comparison between the simula- ted and predictedoo20/20 zigzag test shows a good predictive ability of the three modelling methods. Then all mathematical models obtained by the modelling methods are used to predict theoo10/10 zigzag test ando35 turning circle manoeuvre, and the predicted results are compared with those of simulation tests to demonstrate the good generalization performance of the mathematical models. Finally, the modelling methods are analyzed and compared with each other in terms of the application conditions, the prediction accuracy and the computation speed. An appropriate modelling method can be chosen according to the intended use of the mathematical models and the available data for the system identification.
Snyder, D. M.
1999-01-01
Though Einstein and other physicists recognized the importance of an observer being at rest in an inertial reference frame for the special theory of relativity, the supporting psychological structures were not discussed much by physicists. On the other hand, Rock, a psychologist, wrote of the factors involved in the perception of motion, including one's own motion. Rock thus came to discuss issues of significance to relativity theory, apparently without any significant understanding of how hi...
Jehoshua Eliashberg; Jedid-Jah Jonker; Mohanbir S. Sawhney; Berend Wierenga
2000-01-01
In spite of the high financial stakes involved in marketing new motion pictures, marketing science models have not been applied to the market evaluation of motion pictures. The motion picture industry poses some unique challenges. For example, the consumer adoption process for movies is very sensitive to word-of-mouth interactions, which are difficult to measure and predict the movie has been released. In this article, we undertake the challenge to develop and implement MOVIEMOD—a prerelease ...
Directory of Open Access Journals (Sweden)
Ping Lou
2007-01-01
Full Text Available Based on energy approach, the equations of motion in matrix form for the railway freight vehicle-bridge interaction system are derived, in which the dynamic contact forces between vehicle and bridge are considered as internal forces. The freight vehicle is modelled as a multi-rigid-body system, which comprises one car body, two bogie frames and four wheelsets. The bogie frame is linked with the car body through spring-dashpot suspension systems, and the bogie frame is rigidly linked with wheelsets. The bridge deck, together with railway track resting on bridge, is modelled as a simply supported Bernoulli-Euler beam and its deflection is described by superimposing modes. The direct time integration method is applied to obtain the dynamic response of the vehicle-bridge interaction system at each time step. A computer program has been developed for analyzing this system. The correctness of the proposed procedure is confirmed by one numerical example. The effect of different beam mode numbers and various surface irregularities of beam on the dynamic responses of the vehicle-bridge interaction system are investigated.
International Nuclear Information System (INIS)
The Technical Committee for Piping Systems of the Pressure Vessel Research Committee (PVRC) has recommended new damping values to be used in the seismic analyses of piping systems in nuclear power plants. To evaluate the effect of coupling these recommendations with the use of independent support motion analyses methods, two sets of seismic analyses have been carried out for several piping systems. For each analysis set, the response spectrum results were compared with time history estimates of those results. Comparison tables were then prepared depicting the percentage by which the response spectrum estimates exceeded the time history estimates. By comparing the result tables between both analysis sets, the impact of PVRC damping can be observed. Preliminary results show that the degree of exceedance of the response spectrum estimates based on PVRC damping is less than that based on uniform damping for the same piping problem. Expressed differently the results obtained if ISM methods are coupled with PVRC damping are not as conservative as those obtained using uniform damping
Keshner, Emily A; Kenyon, Robert V; Langston, Jessica
2004-01-01
The purpose of this study was to identify how the postural system weights coincident yet discordant disturbances of the visual and proprioceptive/vestibular systems. Eleven healthy subjects (25-38 yrs) received either fore-aft translations of an immersive, wide field-of-view visual environment (0.1 Hz, +/- 3.7 m/sec), or anterior-posterior translations of the support surface (0.25 Hz, +/- 15 cm/sec), or both concurrently. Kinematics of the head, trunk, and shank were collected with an Optotrak system and angular motion of each segment plotted across time. With only support surface translation, segmental responses were small (1 degrees -2 degrees ) and mostly opposed the direction of sled translation. When only the visual scene was moving, segmental responses increased as the trial progressed. When the inputs were presented coincidentally, response amplitudes were large even at the onset of the trial. Mean RMS values across subjects were significantly greater with combined stimuli than for either stimulus presented alone and areas under the power curve across subjects were significantly increased at the frequency of the visual input when both inputs were presented. Thus, intra-modality dependencies were observed, such that responses to the visual inputs significantly increased and responses to the somatosensory signals reflected the stimulus amplitude only when the two inputs were combined. We believe it unlikely that the role of any single pathway contributing to postural control can be accurately characterized in a static environment if the function of that pathway is context dependent. PMID:15328445
Axial gap rotating electrical machine
Energy Technology Data Exchange (ETDEWEB)
None
2016-02-23
Direct drive rotating electrical machines with axial air gaps are disclosed. In these machines, a rotor ring and stator ring define an axial air gap between them. Sets of gap-maintaining rolling supports bear between the rotor ring and the stator ring at their peripheries to maintain the axial air gap. Also disclosed are wind turbines using these generators, and structures and methods for mounting direct drive rotating electrical generators to the hubs of wind turbines. In particular, the rotor ring of the generator may be carried directly by the hub of a wind turbine to rotate relative to a shaft without being mounted directly to the shaft.
Institute of Scientific and Technical Information of China (English)
Zhen-zhen PENG; Xin-min CHEN; Jun WANG; Ai-jie LI; Zu-jie XU
2013-01-01
Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture (CFPD) under vertically concentrated loading with digital laser speckle (DLS) technique.Methods:Fresh mandible of beagle dog was used to establish the implant-supported CFPD for specimen.DLS technique was employed for measuring the three-dimensional displacement of the prosthesis under vertically concentrated loading ranging from 200 to 3000 g.The effect of the contact tightness on the displacement of CFPD was investigated by means of changing the contact tightness.Results:When an axial concentrated loading was exerted on the pontic of the implant-supported CFPD,the displacement of the CFPD was the greatest.The displacement of the prosthesis decreased with the increase of contact strength.When the contact strength was 0,0.95,and 3.25 N,the displacement of the buccolingual direction was smaller than that of the mesiodistal direction but greater than that of the occlusogingival direction.When the force on the contact area was 6.50 N,the mesiodistal displacement of the prosthesis was the biggest while the buccolingual displacement was the smallest.Conclusions:The implantsupported CFPD is an effective therapy for fully or partially edentulous patients.The restoration of the contact area and the selection of the appropriate contact strength can reduce the displacement of the CFPD,and get a better stress distribution.The most appropriate force value is 3.25 N in this study.
Directory of Open Access Journals (Sweden)
Walt Wells
2008-01-01
Full Text Available Our objective in this paper is to solve a second order differential equation for a long, simply supported column member subjected to a lateral axial load using Heun's numerical method. We will use the solution to find the critical load at which the column member will fail due to buckling. We will calculate this load using Euler's derived analytical approach for an exact solution, as well as Euler's Numerical Method. We will then compare the three calculated values to see how much they deviate from one another. During the critical load calculation, it will be necessary to calculate the moment of inertia for the column member.
Urban-Woldron, Hildegard
2012-03-01
The recent implementation of technology in the classroom is probably one of the most challenging innovations that many teachers are having to confront today. Teachers have to develop a knowledge base that goes beyond technology proficiency, into learning about how technology, for example, can be used for various forms of representations of subject matters. This article aims to report on the investigation of the motion of a rebounding trolley, bringing together physics content, pedagogy, and technology to enhance student thinking and construction of knowledge. The activity, called "Rebounding Trolley," uses data logging and helps to emphasize the idea that velocity and acceleration can be in opposite directions.
Can the vertical motions in the eyewall of tropical cyclones support persistent UAV flight?
Poh, Chung-Kiak
2014-01-01
Powered flights in the form of manned or unmanned aerial vehicles (UAVs) have been flying into tropical cyclones to obtain vital atmospheric measurements with flight duration typically lasting between 12 and 36 hours. Convective vertical motion properties of tropical cyclones have previously been studied. This work investigates the possibility to achieve persistent flight by harnessing the generally pervasive updrafts in the eyewall of tropical cyclones. A sailplane UAV capable of vertical take-off and landing (VTOL) is proposed and its flight characteristics simulated. Results suggest that the concept of persistent flight within the eyewall is promising and may be extendable to the rainband regions.
Institute of Scientific and Technical Information of China (English)
王雪刚; 邹早建; 余龙; 蔡韡
2015-01-01
Based on support vector machines, three modeling methods, i.e., white-box modeling, grey-box modeling and black-box modeling of ship manoeuvring motion in 4 degrees of freedom are investigated. With the whole-ship mathematical model for ship manoeuvring motion, in which the hydrodynamic coefficients are obtained from roll planar motion mechanism test, some zigzag tests and turning circle manoeuvres are simulated. In the white-box modeling and grey-box modeling, the training data taken every 5 s from the simulated 20°/20° zigzag test are used, while in the black-box modeling, the training data taken every 5 s from the simulated 15°/15°, 20°/20° zigzag tests and 15°, 25° turning manoeuvres are used; and the trained support vector machines are used to predict the whole 20°/20° zigzag test. Comparisons between the simulated and predicted 20°/20° zigzag tests show good predictive ability of the proposed methods. Besides, all mathematical models obtained by the proposed modeling methods are used to predict the 10°/10° zigzag test and 35° turning circle manoeuvre, and the predicted results are compared with those of simulation tests to demonstrate the good generalization performance of the mathematical models. Finally, the proposed modeling methods are analyzed and compared with each other in aspects of application conditions, prediction accuracy and computation speed. The appropriate modeling method can be chosen according to the intended use of the mathematical models and the available data needed for system identification.
Precise ground motion measurements to support multi-hazard analysis in Jakarta
Koudogbo, Fifamè; Duro, Javier; Garcia Robles, Javier; Abidin, Hasanuddin Z.
2015-04-01
Jakarta is the capital of Indonesia and is home to approximately 10 million people on the coast of the Java Sea. The Capital District of Jakarta (DKI) sits in the lowest lying areas of the basin. Its topography varies, with the northern part just meters above current sea level and lying on a flood plain. Subsequently, this portion of the city frequently floods. Flood events have been increasing in severity during the past decade. The February 2007 event inundated 235 Km2 (about 36%) of the city, by up to seven meters in some areas. This event affected more than 2.6 million people; the estimated financial and economic losses from this event amounted to US900 million [1][2]. Inundations continue to occur under any sustained rainfall conditions. Flood events in Jakarta are expected to become more frequent in coming years, with a shift from previously slow natural processes with low frequency to a high frequency process resulting in severe socio-economic damage. Land subsidence in Jakarta results in increased vulnerability to flooding due to the reduced gravitational capacity to channel storm flows to the sea and an increased risk of tidal flooding. It continues at increasingly alarming rates, principally caused by intensive deep groundwater abstraction [3]. Recent studies have found typical subsidence rates of 7.5-10 cm a year. In localized areas of north Jakarta subsidence in the range 15-25 cm a year is occurring which, if sustained, would result in them sinking to 4-5 m below sea level by 2025 [3]. ALTAMIRA INFORMATION, company specialized in ground motion monitoring, has developed GlobalSARTM, which combines several processing techniques and algorithms based on InSAR technology, to achieve ground motion measurements with millimetric precision and high accuracy [4]. Within the RASOR (Rapid Analysis and Spatialisation and Of Risk) project, ALTAMIRA INFORMATION will apply GlobalSARTM to assess recent land subsidence in Jakarta, based on the processing of Very High
Shiell, Martha M; Champoux, François; Zatorre, Robert J
2016-01-01
After sensory loss, the deprived cortex can reorganize to process information from the remaining modalities, a phenomenon known as cross-modal reorganization. In blind people this cross-modal processing supports compensatory behavioural enhancements in the nondeprived modalities. Deaf people also show some compensatory visual enhancements, but a direct relationship between these abilities and cross-modally reorganized auditory cortex has only been established in an animal model, the congenitally deaf cat, and not in humans. Using T1-weighted magnetic resonance imaging, we measured cortical thickness in the planum temporale, Heschl's gyrus and sulcus, the middle temporal area MT+, and the calcarine sulcus, in early-deaf persons. We tested for a correlation between this measure and visual motion detection thresholds, a visual function where deaf people show enhancements as compared to hearing. We found that the cortical thickness of a region in the right hemisphere planum temporale, typically an auditory region, was greater in deaf individuals with better visual motion detection thresholds. This same region has previously been implicated in functional imaging studies as important for functional reorganization. The structure-behaviour correlation observed here demonstrates this area's involvement in compensatory vision and indicates an anatomical correlate, increased cortical thickness, of cross-modal plasticity. PMID:26885405
Directory of Open Access Journals (Sweden)
Martha M. Shiell
2016-01-01
Full Text Available After sensory loss, the deprived cortex can reorganize to process information from the remaining modalities, a phenomenon known as cross-modal reorganization. In blind people this cross-modal processing supports compensatory behavioural enhancements in the nondeprived modalities. Deaf people also show some compensatory visual enhancements, but a direct relationship between these abilities and cross-modally reorganized auditory cortex has only been established in an animal model, the congenitally deaf cat, and not in humans. Using T1-weighted magnetic resonance imaging, we measured cortical thickness in the planum temporale, Heschl’s gyrus and sulcus, the middle temporal area MT+, and the calcarine sulcus, in early-deaf persons. We tested for a correlation between this measure and visual motion detection thresholds, a visual function where deaf people show enhancements as compared to hearing. We found that the cortical thickness of a region in the right hemisphere planum temporale, typically an auditory region, was greater in deaf individuals with better visual motion detection thresholds. This same region has previously been implicated in functional imaging studies as important for functional reorganization. The structure-behaviour correlation observed here demonstrates this area’s involvement in compensatory vision and indicates an anatomical correlate, increased cortical thickness, of cross-modal plasticity.
Shiell, Martha M.; Champoux, François; Zatorre, Robert J.
2016-01-01
After sensory loss, the deprived cortex can reorganize to process information from the remaining modalities, a phenomenon known as cross-modal reorganization. In blind people this cross-modal processing supports compensatory behavioural enhancements in the nondeprived modalities. Deaf people also show some compensatory visual enhancements, but a direct relationship between these abilities and cross-modally reorganized auditory cortex has only been established in an animal model, the congenitally deaf cat, and not in humans. Using T1-weighted magnetic resonance imaging, we measured cortical thickness in the planum temporale, Heschl's gyrus and sulcus, the middle temporal area MT+, and the calcarine sulcus, in early-deaf persons. We tested for a correlation between this measure and visual motion detection thresholds, a visual function where deaf people show enhancements as compared to hearing. We found that the cortical thickness of a region in the right hemisphere planum temporale, typically an auditory region, was greater in deaf individuals with better visual motion detection thresholds. This same region has previously been implicated in functional imaging studies as important for functional reorganization. The structure-behaviour correlation observed here demonstrates this area's involvement in compensatory vision and indicates an anatomical correlate, increased cortical thickness, of cross-modal plasticity. PMID:26885405
Axial Thermal Rotation of Slender Rods
Li, Dichuan; Fakhri, Nikta; Pasquali, Matteo; Biswal, Sibani Lisa
2011-05-01
Axial rotational diffusion of rodlike polymers is important in processes such as microtubule filament sliding and flagella beating. By imaging the motion of small kinks along the backbone of chains of DNA-linked colloids, we produce a direct and systematic measurement of axial rotational diffusivity of rods both in bulk solution and near a wall. The measured diffusivities decrease linearly with the chain length, irrespective of the distance from a wall, in agreement with slender-body hydrodynamics theory. Moreover, the presence of small kinks does not affect the chain’s axial diffusivity. Our system and measurements provide insights into fundamental axial diffusion processes of slender objects, which encompass a wide range of entities including biological filaments and linear polymer chains.
Nonlinear Models for Transverse Forced Vibration of Axially Moving Viscoelastic Beams
Directory of Open Access Journals (Sweden)
Hu Ding
2011-01-01
Full Text Available Nonlinear models of transverse vibration of axially moving viscoelastic beams subjected external transverse loads via steady-state periodical response are numerically investigated. An integro-partial-differential equation and a partial-differential equation of transverse motion can be derived respectively from a model of the coupled planar vibration for an axially moving beam. The finite difference scheme is developed to calculate steady-state response for the model of coupled planar and the two models of transverse motion under the simple support boundary. Numerical results indicate that the amplitude of the steady-state response for the model of coupled vibration and two models of transverse vibration predict qualitatively the same tendencies with the changing parameters and the integro-partial-differential equation gives results more closely to the coupled planar vibration.
On two transverse nonlinear models of axially moving beams
Institute of Scientific and Technical Information of China (English)
DING Hu; CHEN LiQun
2009-01-01
Nonlinear models of transverse vibration of axially moving beams are computationally investigated. A partial-differential equation is derived from the governing equation of coupled planar motion by omit-ting its longitudinal terms. The model can be reduced to an integro-partial-differential equation by av-eraging the beam disturbed tension. Numerical schemes are respectively presented for the governing equations of coupled planar and the two governing equations of transverse motion via the finite dif-ference method and differential quadrature method under the fixed boundary and the simple support boundary. A steel beam and a copper beam are treated as examples to demonstrate the deviations of the solutions to the two transverse equations from the solution to the coupled equation. The numerical results indicate that the differences increase with the amplitude of vibration and the axial speed. Both models yield almost the same precision results for small amplitude vibration and the inte-gro-partial-differential equation gives better results for large amplitude vibration.
On two transverse nonlinear models of axially moving beams
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Nonlinear models of transverse vibration of axially moving beams are computationally investigated. A partial-differential equation is derived from the governing equation of coupled planar motion by omit- ting its longitudinal terms. The model can be reduced to an integro-partial-differential equation by av- eraging the beam disturbed tension. Numerical schemes are respectively presented for the governing equations of coupled planar and the two governing equations of transverse motion via the finite dif- ference method and differential quadrature method under the fixed boundary and the simple support boundary. A steel beam and a copper beam are treated as examples to demonstrate the deviations of the solutions to the two transverse equations from the solution to the coupled equation. The numerical results indicate that the differences increase with the amplitude of vibration and the axial speed. Both models yield almost the same precision results for small amplitude vibration and the inte- gro-partial-differential equation gives better results for large amplitude vibration.
Institute of Scientific and Technical Information of China (English)
Qiaoyun YAN; Hu DING; Liqun CHEN
2015-01-01
This investigation focuses on the nonlinear dynamic behaviors in the trans-verse vibration of an axially accelerating viscoelastic Timoshenko beam with the external harmonic excitation. The parametric excitation is caused by the harmonic fluctuations of the axial moving speed. An integro-partial-differential equation governing the transverse vibration of the Timoshenko beam is established. Many factors are considered, such as viscoelasticity, the finite axial support rigidity, and the longitudinally varying tension due to the axial acceleration. With the Galerkin truncation method, a set of nonlinear ordinary differential equations are derived by discretizing the governing equation. Based on the numerical solutions, the bifurcation diagrams are presented to study the effect of the external transverse excitation. Moreover, the frequencies of the two excitations are assumed to be multiple. Further, five different tools, including the time history, the Poincar´e map, and the sensitivity to initial conditions, are used to identify the motion form of the nonlinear vibration. Numerical results also show the characteristics of the quasiperiodic motion of the translating Timoshenko beam under an incommensurable re-lationship between the dual-frequency excitations.
International Nuclear Information System (INIS)
The purpose of this calculation is to develop axial profiles for estimating the axial variation in burnup of a boiling water reactor (BWR) assembly spent nuclear fuel (SNF) given the average burnup of an assembly. A discharged fuel assembly typically exhibits higher burnup in the center and lower burnup at the ends of the assembly. Criticality safety analyses taking credit for SNF burnup must account for axially varying burnup relative to calculations based on uniformly distributed assembly average burnup due to the under-burned tips. Thus, accounting for axially varying burnup in criticality analyses is also referred to as accounting for the ''end effect'' reactivity. The magnitude of the reactivity change due to ''end effect'' is dependent on the initial assembly enrichment, the assembly average burnup, and the particular axial profile characterizing the burnup distribution. The set of bounding axial profiles should incorporate multiple BWR core designs and provide statistical confidence (95 percent confidence that 95 percent of the population is bound by the profile) that end nodes are conservatively represented. The profiles should also conserve the overall burnup of the fuel assembly. More background on BWR axial profiles is provided in Attachment I
Energy Technology Data Exchange (ETDEWEB)
J. Huffer
2004-09-28
The purpose of this calculation is to develop axial profiles for estimating the axial variation in burnup of a boiling water reactor (BWR) assembly spent nuclear fuel (SNF) given the average burnup of an assembly. A discharged fuel assembly typically exhibits higher burnup in the center and lower burnup at the ends of the assembly. Criticality safety analyses taking credit for SNF burnup must account for axially varying burnup relative to calculations based on uniformly distributed assembly average burnup due to the under-burned tips. Thus, accounting for axially varying burnup in criticality analyses is also referred to as accounting for the ''end effect'' reactivity. The magnitude of the reactivity change due to ''end effect'' is dependent on the initial assembly enrichment, the assembly average burnup, and the particular axial profile characterizing the burnup distribution. The set of bounding axial profiles should incorporate multiple BWR core designs and provide statistical confidence (95 percent confidence that 95 percent of the population is bound by the profile) that end nodes are conservatively represented. The profiles should also conserve the overall burnup of the fuel assembly. More background on BWR axial profiles is provided in Attachment I.
Signatures for axial chromodynamics
International Nuclear Information System (INIS)
Within the context of basic left-right symmetry and the hypothesis of unification of weak, electromagnetic and strong forces at a mass level approximately equal to 104-106 GeV, relatively light ''mass'' axial gluons, confined or liberated, must be postulated. The authors remark that the existence of such ''light'' axial gluons supplementing the familiar vector octet preserves the successes of QCD, both for deep inelastic processes and charmonium physics. Through the characteristic spin-spin force, generated by their exchange, they may even help resolve some of the discrepancies between vector QCD predictions and charmonium physics. The main remark of this note is that if colour is liberated, not only vector but also axial-vector gluons are produced in high-energy e-e+ experiments, e.g. at PETRA and PEP, with fairly large cross-section. Distinctive decay modes of such liberated axial gluons are noted
Surface nanoscale axial photonics
Sumetsky, M.; Fini, J. M.
2011-01-01
Dense photonic integration promises to revolutionize optical computing and communications. However, efforts towards this goal face unacceptable attenuation of light caused by surface roughness in microscopic devices. Here we address this problem by introducing Surface Nanoscale Axial Photonics (SNAP). The SNAP platform is based on whispering gallery modes circulating around the optical fiber surface and undergoing slow axial propagation readily described by the one-dimensional Schr\\"odinger e...
NON-LINEAR FORCED VIBRATION OF AXIALLY MOVING VISCOELASTIC BEAMS
Institute of Scientific and Technical Information of China (English)
Yang Xiaodong; Chen Li-Qun
2006-01-01
The non-linear forced vibration of axially moving viscoelastic beams excited by the vibration of the supporting foundation is investigated. A non-linear partial-differential equation governing the transverse motion is derived from the dynamical, constitutive equations and geometrical relations. By referring to the quasi-static stretch assumption, the partial-differential non-linearity is reduced to an integro-partial-differential one. The method of multiple scales is directly applied to the governing equations with the two types of non-linearity, respectively. The amplitude of near- and exact-resonant steady state is analyzed by use of the solvability condition of eliminating secular terms. Numerical results are presented to show the contributions of foundation vibration amplitude, viscoelastic damping, and nonlinearity to the response amplitude for the first and the second mode.
International Nuclear Information System (INIS)
The selection and application of coordinate systems is an important issue in physics. However, considering different frames of references in a given problem sometimes seems un-intuitive and is difficult for students. We present a concrete problem of projectile motion which vividly demonstrates the value of considering different frames of references. We use this example to explore the effectiveness of video-based motion analysis (VBMA) as an instructional technique at university level in enhancing students’ understanding of the abstract concept of coordinate systems. A pilot study with 47 undergraduate students indicates that VBMA instruction improves conceptual understanding of this issue. (paper)
Institute of Scientific and Technical Information of China (English)
Hu Ding; Li-Qun Chen
2011-01-01
Steady-state periodical response is investigated for an axially moving viscoelastic beam with hybrid supports via approximate analysis with numerical confirmation.It is assumed that the excitation is spatially uniform and temporally harmonic. The transverse motion of axially moving beams is governed by a nonlinear partial-differential equation and a nonlinear integro-partial-differential equation. The material time derivative is used in the viscoelastic constitutive relation. The method of multiple scales is applied to the governing equations to investigate primary resonances under general boundary conditions. It is demonstrated that the mode uninvolved in the resonance has no effect on the steady-state response. Numerical examples are presented to demonstrate the effects of the boundary constraint stiffness on the amplitude and the stability of the steady-state response. The results derived for two governing equations are qualitatively the same, but quantitatively different. The differential quadrature schemes are developed to verify those results via the method of multiple scales.
Nonlinear vibrations and imperfection sensitivity of a cylindrical shell containing axial fluid flow
del Prado, Z.; Gonçalves, P. B.; Païdoussis, M. P.
2009-10-01
The high imperfection sensitivity of cylindrical shells under static compressive axial loads is a well-known phenomenon in structural stability. On the other hand, less is known of the influence of imperfections on the nonlinear vibrations of these shells under harmonic axial loads. The aim of this work is to study the simultaneous influence of geometric imperfections and an axial fluid flow on the nonlinear vibrations and instabilities of simply supported circular cylindrical shells under axial load. The fluid is assumed to be non-viscous and incompressible and the flow to be isentropic and irrotational. The behavior of the thin-walled shell is modeled by Donnell's nonlinear shallow-shell equations. It is subjected to a static uniform compressive axial pre-load plus a harmonic axial load. A low-dimensional modal expansion, which satisfies the relevant boundary and continuity conditions, and takes into account all relevant nonlinear modal interactions observed in the past in the nonlinear vibrations of cylindrical shells with and without flow is used together with the Galerkin method to derive a set of eight coupled nonlinear ordinary differential equations of motion which are, in turn, solved by the Runge-Kutta method. The shell is considered to be initially at rest, in a position corresponding to a pre-buckling configuration. Then, a harmonic excitation is applied and conditions for parametric instability and dynamic snap-through are sought. The results clarify the marked influence of geometric imperfections and fluid flow on the dynamic stability boundaries, bifurcations and basins of attraction.
Lee, Victor R.
2015-01-01
Biomechanics, and specifically the biomechanics associated with human movement, is a potentially rich backdrop against which educators can design innovative science teaching and learning activities. Moreover, the use of technologies associated with biomechanics research, such as high-speed cameras that can produce high-quality slow-motion video,…
Directory of Open Access Journals (Sweden)
F. Aguilar Parés
1999-01-01
Full Text Available Durante el movimiento de un material en un transportador de sinfín surge una fuerza en dirección axial que influye en laselección de uno de los cojinetes de apoyo del equipo. En el artículo aparecen algunas soluciones constructivas que tienen encuentan la fuerza axial. Por otro lado se establece la relación entre la fuerza axial y el empuje axial y se precisa de quiendepende el sentido del empuje axial. Por último se propone un modelo matemático que relaciona la fuerza axial con la potenciarequerida por el equipo.Palabras claves: Transportador de sinf in, fuerza axial , empuje axial ._________________________________________________________________________AbstractDuring the movement of material in a screw conveyor surge a force in axial direction that influence in the selection of one ofthe equipment support bearings. Some constructive solutions appear in the article for considering the axial force. In the otherhand it is established the relation between axial force and axial thurst and it is precised whose direction thurst axial depend of.Finally it is proposed a mathematic model that relates the axial force with the power required by the equipment.Key words: Screw conveyor, axial force, axial thurst .
PWR AXIAL BURNUP PROFILE ANALYSIS
International Nuclear Information System (INIS)
The purpose of this activity is to develop a representative ''limiting'' axial burnup profile for pressurized water reactors (PWRs), which would encompass the isotopic axial variations caused by different assembly irradiation histories, and produce conservative isotopics with respect to criticality. The effect that the low burnup regions near the ends of spent fuel have on system reactivity is termed the ''end-effect''. This calculation will quantify the end-effects associated with Pressurized Water Reactor (PWR) fuel assemblies emplaced in a hypothetical 21 PWR waste package. The scope of this calculation covers an initial enrichment range of 3.0 through 5.0 wt% U-235 and a burnup range of 10 through 50 GWd/MTU. This activity supports the validation of the process for ensuring conservative generation of spent fuel isotopics with respect to criticality safety applications, and the use of burnup credit for commercial spent nuclear fuel. The intended use of these results will be in the development of PWR waste package loading curves, and applications involving burnup credit. Limitations of this evaluation are that the limiting profiles are only confirmed for use with the B andW 15 x 15 fuel assembly design. However, this assembly design is considered bounding of all other typical commercial PWR fuel assembly designs. This calculation is subject to the Quality Assurance Requirements and Description (QARD) because this activity supports investigations of items or barriers on the Q-list (YMP 2001)
PWR AXIAL BURNUP PROFILE ANALYSIS
Energy Technology Data Exchange (ETDEWEB)
J.M. Acaglione
2003-09-17
The purpose of this activity is to develop a representative ''limiting'' axial burnup profile for pressurized water reactors (PWRs), which would encompass the isotopic axial variations caused by different assembly irradiation histories, and produce conservative isotopics with respect to criticality. The effect that the low burnup regions near the ends of spent fuel have on system reactivity is termed the ''end-effect''. This calculation will quantify the end-effects associated with Pressurized Water Reactor (PWR) fuel assemblies emplaced in a hypothetical 21 PWR waste package. The scope of this calculation covers an initial enrichment range of 3.0 through 5.0 wt% U-235 and a burnup range of 10 through 50 GWd/MTU. This activity supports the validation of the process for ensuring conservative generation of spent fuel isotopics with respect to criticality safety applications, and the use of burnup credit for commercial spent nuclear fuel. The intended use of these results will be in the development of PWR waste package loading curves, and applications involving burnup credit. Limitations of this evaluation are that the limiting profiles are only confirmed for use with the B&W 15 x 15 fuel assembly design. However, this assembly design is considered bounding of all other typical commercial PWR fuel assembly designs. This calculation is subject to the Quality Assurance Requirements and Description (QARD) because this activity supports investigations of items or barriers on the Q-list (YMP 2001).
Barber, Tim Daniel (Inventor); Hindle, Timothy (Inventor); Young, Ken (Inventor); Davis, Torey (Inventor)
2014-01-01
Embodiments of a launch lock assembly are provided, as are embodiments of a spacecraft isolation system including one or more launch lock assemblies. In one embodiment, the launch lock assembly includes first and second mount pieces, a releasable clamp device, and an axial gap amplification device. The releasable clamp device normally maintains the first and second mount pieces in clamped engagement; and, when actuated, releases the first and second mount pieces from clamped engagement to allow relative axial motion there between. The axial gap amplification device normally residing in a blocking position wherein the gap amplification device obstructs relative axial motion between the first and second mount pieces. The axial gap amplification device moves into a non-blocking position when the first and second mount pieces are released from clamped engagement to increase the range of axial motion between the first and second mount pieces.
A non-integral, axial-force measuring element
Ringel, M.; Levin, D.; Seginer, A.
1989-10-01
A new approach to the measurement of the axial force is presented. A nonintegral axial-force measuring element, housed within the wind-tunnel model, avoids the interactions that are caused by nonlinear elastic phenomena characteristic of integral balances. The new design overcomes other problems, such as friction, misalignment and relative motion between metric elements, that plagued previous attempts at separate measurement of the axial force. Calibration and test results prove the ability of the new approach to duplicate and even surpass the results of much more complicated and expensive integral balances. The advantages of the new design make it the best known solution for particular measurement problems.
Energy Technology Data Exchange (ETDEWEB)
Caspall, J.J.; Gray, M.D.; Caille, G.W. [Georgia Tech Research Institute, Undersea Research Program Office, Georgia Institute of Technology, Atlanta, Georgia 30332-0810 (United States); Jarzynski, J.; Rogers, P.H.; McCall, G.S. II [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States)
1996-04-01
The application of contact motion sensors, such as accelerometers, in the measurement of the vibration of compliant surfaces underwater may lead to errors in the evaluation of certain types of surface motion. An underwater scanning laser Doppler vibrometer (USLDV) was used to measure the scattered velocity field due to a mock sensor (rigid, neutrally buoyant cylindrical body) on a compliant surface (the outer surface of a thin cylindrical shell coated with a layer of soft rubber). Axially propagating waves were launched in the shell by a ring of 10 uniformly distributed shakers located near one end of the shell and driven with a short pulse. The outer surface of the coating was scanned over a short line segment in the axial direction with and without the mock sensor attached. The extracted scattered field, consisted of high wavenumber fluid-solid interface waves accompanied by rotational motion of the mock sensor. [Work supported by ONR] {copyright} {ital 1996 American Institute of Physics.}
On renormalization of axial anomaly
International Nuclear Information System (INIS)
It is shown that multiplicative renormalization of the axial singlet current results in renormalization of the axial anomaly in all orders of perturbation theory. It is a necessary condition for the Adler - Bardeen theorem being valid. 10 refs.; 2 figs
Axial compressor stability enhancement
Houghton, Timothy Oliver.
2010-01-01
Aircraft jet engines must operate in a stable manner at all times. One source of instability is compressor stall. Stall problems can be reduced by machining cavities into the compressor casing adjacent to the rotor blades. This ?casing treatment? is the focus of the present work. Two treatment configurations are tested: circumferential grooves cut into the casing above the rotor blades, and axial slots cut into the casing adjacent to the rotor blade leading edges. The performance of a single ...
Bell, M B
2007-01-01
Radio loud jetted sources with and without extended inner jet structure show good agreement with the simple ballistic ejection scenario proposed in the decreasing intrinsic redshift (DIR) model, where, because of projection effects, those that show the most obvious extended structure and large angular motions are assumed to have jets that lie close to the plane of the sky, and those with little or no structure and small angular motions are assumed to have jets that are coming almost directly towards us. This simple model also predicts several other relations seen in the raw data that, in some cases, may be less easily explained if the redshifts are cosmological and relativistic ejection is required. In particular, for radio-loud sources the source number density is found to be high for sources that are not Doppler boosted but low for highly boosted sources. This is opposite to what is expected, suggesting that Doppler boosting may not be involved at all, which would be in agreement with the DIR model. If so, ...
Axial anomaly, Dirac sea, and the chiral magnetic effect
Kharzeev, Dmitri E.
2010-01-01
Gribov viewed the axial anomaly as a manifestation of the collective motion of charged fermions with arbitrarily high momenta in the vacuum. In the presence of an external magnetic field and a chirality imbalance, this collective motion becomes directly observable in the form of the electric current - this is the chiral magnetic effect (CME). I give an elementary introduction into the physics of CME, and discuss some recent developments.
International Nuclear Information System (INIS)
Recently, software-based programmable logic controller (PLC) systems, which are implemented in standard PLC languages on general hardware, are gaining popularity because they overcome the limitations of classical hardware PLC systems. Another noticeable trend is that the use of integrated development environment (IDE) is becoming important. IDEs can help developers to easily manage the growing complexity of modern control systems. Furthermore, industrial Ethernet, e. g. EtherCAT, is becoming widely accepted as a replacement for conventional fieldbuses in the distributed control domain because it offers favorable features such as short transmission delay, high bandwidth, and low cost. In this paper, we implemented the extension of open source IDE, called Beremiz, for developing EtherCAT-based real-time, synchronized motion control applications. We validated the EtherCAT system management features and the real-time responsiveness of the control function by using commercial EtherCAT drives and evaluation boards
Cervical Spine Axial Rotation Goniometer Design
Directory of Open Access Journals (Sweden)
Emin Ulaş Erdem
2012-06-01
Full Text Available To evaluate the cervical spine rotation movement is quiet harder than other joints. Configuration and arrangement of current goniometers and devices is not always practic in clinics and some methods are quiet expensive. The cervical axial rotation goniometer designed by the authors is consists of five pieces (head apparatus, chair, goniometric platform, eye pads and camera. With this goniometer design a detailed evaluation of cervical spine range of motion can be obtained. Besides, measurement of "joint position sense" which is recently has rising interest in researches can be made practically with this goniometer.
Directory of Open Access Journals (Sweden)
Cornel Hatiegan
2013-01-01
Full Text Available This paper presents the differential biharmonic equation of thin plates through which, the vibration mode shapes for a rectangular thin plate simply supported on contour were obtained. Also, the first four vibration mode and the first four natural frequencies of this rectangular thin plate of steel, were obtained. Using MATLAB software, the vibration mode shapes were graphically represented.
Swaak, Janine; And Others
In this study, learners worked with a simulation of harmonic oscillation. Two supportive measures were introduced: model progression and assignments. In model progression, the model underlying the simulation is not offered in its full complexity from the start, but variables are gradually introduced. Assignments are small exercises that help the…
DYNAMIC RESPONSES OF VISCOELASTIC AXIALLY MOVING BELT
Institute of Scientific and Technical Information of China (English)
李映辉; 高庆; 蹇开林; 殷学纲
2003-01-01
Based on the Kelvin viscoelastic differential constitutive law and the motion equation of the axially moving belt, the nonlinear dynamic model of the viscoelastic axial moving belt was established. And then it was reduced to be a linear differential system which the analytical solutions with a constant transport velocity and with a harmonically varying transport velocity were obtained by applying Lie group transformations. According to the nonlinear dynamic model, the effects of material parameters and the steady-state velocity and the perturbed axial velocity of the belt on the dynamic responses of the belts were investigated by the research of digital simulation. The result shows: 1 ) The nonlinear vibration frequency of the belt will become small when the relocity of the belt increases. 2 ) Increasing the value of viscosity or decreasing the value of elasticity leads to a deceasing in vibration frequencies. 3 ) The most effects of the transverse amplitudes come from the frequency of the perturbed velocity when the belt moves with harmonic velocity.
Axial skeletal CT densitometry
International Nuclear Information System (INIS)
Since the discovery of the Roentgen ray a precise and accurate assessment of bone mineral content has been a challenge to many investigators. A number of methods have been developed but no one satisfied. Considering its technical possibilities computed tomography is very promising in determination of bone mineral content (BMC). The new modality enables BMC estimations in the axial skeletal trabecular bone. CT densitometry can be performed on a normal commercially available third generation whole body CT scanner. No dedicated device in a special clinical set-up is necessary. In this study 106 patients, most of them clinically suspected of osteoporosis, were examined. The new method CT densitometry has been evaluated. The results have been correlated to alternative BMC determination methods. (Auth.)
Claus, Andrew P; Verrel, Julius; Pounds, Paul E I; Shaw, Renee C; Brady, Niamh; Chew, Min T; Dekkers, Thomas A; Hodges, Paul W
2016-05-01
Sudden application of load along a sagittal or coronal axis has been used to study trunk stiffness, but not axial (vertical) load. This study introduces a new method for sudden-release axial load perturbation. Prima facie validity was supported by comparison with standard mechanical systems. We report the response of the human body to axial perturbation in sitting and standing and within-day repeatability of measures. Load of 20% of body weight was released from light contact onto the shoulders of 22 healthy participants (10 males). Force input was measured via force transducers at shoulders, output via a force plate below the participant, and kinematics via 3-D motion capture. System identification was used to fit data from the time of load release to time of peak load-displacement, fitting with a 2nd-order mass-spring-damper system with a delay term. At peak load-displacement, the mean (SD) effective stiffness measured with this device for participants in sitting was 12.0(3.4)N/mm, and in standing was 13.3(4.2)N/mm. Peak force output exceeded input by 44.8 (10.0)% in sitting and by 30.4(7.9)% in standing. Intra-class correlation coefficients for within-day repeatability of axial stiffness were 0.58 (CI: -0.03 to 0.83) in sitting and 0.82(0.57-0.93) in standing. Despite greater degrees of freedom in standing than sitting, standing involved lesser time, downward displacement, peak output force and was more repeatable in defending upright postural control against the same axial loads. This method provides a foundation for future studies of neuromuscular control with axial perturbation. PMID:26968087
Fullenkamp, Adam M; Campbell, Brian M; Laurent, C Matthew; Lane, Amanda Paige
2015-10-01
To date, biomechanical analyses of soccer kicking have focused predominantly on lower-extremity motions, with little emphasis on the trunk and upper body. The purpose of this study was to evaluate differences in trunk axial kinematics between novice (n = 10) and skilled (n = 10) participants, as well as to establish the relationship of trunk axial motion and sagittal plane thigh rotation to poststrike ball velocity. Three-dimensional body segmental motion data were captured using high-resolution motion analysis (120 Hz) while each participant completed 5 maximal instep soccer-style kicks. The results demonstrate that skilled participants use 53% greater axial trunk range of motion compared with novice participants (P soccer athletes. PMID:26099160
Axial anomaly in nonrenormalizable theories
International Nuclear Information System (INIS)
The anomaly for the axial current in nonrenormalizable theories with electromagnetic coupling is considered. The spinor electrodynamics with Pauli term is examined in detail using the Feynman graph technique and the point-splitting method. The same finite value for the axial anomaly emerges. (author)
Rapalino, Otto; Smirniotopoulos, James G
2016-01-01
Extra-axial brain tumors are the most common adult intracranial neoplasms and encompass a broad spectrum of pathologic subtypes. Meningiomas are the most common extra-axial brain tumor (approximately one-third of all intracranial neoplasms) and typically present as slowly growing dural-based masses. Benign meningiomas are very common, and may occasionally be difficult to differentiate from more aggressive subtypes (i.e., atypical or malignant varieties) or other dural-based masses with more aggressive biologic behavior (e.g., hemangiopericytoma or dural-based metastases). Many neoplasms that typically affect the brain parenchyma (intra-axial), such as gliomas, may also present with primary or secondary extra-axial involvement. This chapter provides a general and concise overview of the common types of extra-axial tumors and their typical imaging features. PMID:27432671
Build Axial Gradient Field by Using Axial Magnetized Permanent Rings
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Axial magnetic field produced by an axial magnetized permanent ring was studied. For two permanent rings, if they are magnetized in the same directions, a nearly uniform axial field can be produced. If they are magnetized in opposite direction,an axial gradient magnetic field can be generated, with the field range changing from -B0 to B0. A permanent magnet with a high axial gradient field was fabricated, the measured results agree with the PANDIRA calculation very well. For wider usage,it is desirable for the field gradient to be changed. Some methods to produce the variable gradient field are presented. These kinds of axial gradient magnetic field can also be used as a beam focusing for linear accelerator if the periodic field can be produced along the beam trajectory. The axial magnetic field is something like a solenoid, large stray field will leak to the outside environment if no method is taken to control them. In this paper, one method is illustrated to shield off the outside leakage field.
Notari, Alessio
2016-01-01
We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term $\\frac{\\phi}{f_\\gamma} F \\tilde{F}$, such as in the case of an axion. Gauge fields in this case are known to experience tachyonic growth and therefore can backreact on the background as an effective dissipation into radiation energy density $\\rho_R$, which which can lead to inflation without the need of a flat potential. We analyze the system, for momenta $k$ smaller than the cutoff $f_\\gamma$, including numerically the backreaction. We consider the evolution from a given static initial condition and explicitly show that, if $f_\\gamma$ is smaller than the field excursion $\\phi_0$ by about a factor of at least ${\\cal O} (20)$, there is a friction effect which turns on before that the field can fall down and which can then lead to a very long stage of inflation with a generic potential. In addition we find superimposed oscillations, which would get imprinted on any kind of...
Bode, Hans R.
2009-01-01
Morphogen gradients play an important role in pattern formation during early stages of embryonic development in many bilaterians. In an adult hydra, axial patterning processes are constantly active because of the tissue dynamics in the adult. These processes include an organizer region in the head, which continuously produces and transmits two signals that are distributed in gradients down the body column. One signal sets up and maintains the head activation gradient, which is a morphogenetic gradient. This gradient confers the capacity of head formation on tissue of the body column, which takes place during bud formation, hydra's mode of asexual reproduction, as well as during head regeneration following bisection of the animal anywhere along the body column. The other signal sets up the head inhibition gradient, which prevents head formation, thereby restricting bud formation to the lower part of the body column in an adult hydra. Little is known about the molecular basis of the two gradients. In contrast, the canonical Wnt pathway plays a central role in setting up and maintaining the head organizer. PMID:20066073
International Nuclear Information System (INIS)
In the present study, the coupled nonlinear dynamics of an axially moving viscoelastic beam with time-dependent axial speed is investigated employing a numerical technique. The equations of motion for both the transverse and longitudinal motions are obtained using Newton’s second law of motion and the constitutive relations. A two-parameter rheological model of the Kelvin–Voigt energy dissipation mechanism is employed in the modelling of the viscoelastic beam material, in which the material time derivative is used in the viscoelastic constitutive relation. The Galerkin method is then applied to the coupled nonlinear equations, which are in the form of partial differential equations, resulting in a set of nonlinear ordinary differential equations (ODEs) with time-dependent coefficients due to the axial acceleration. A change of variables is then introduced to this set of ODEs to transform them into a set of first-order ordinary differential equations. A variable step-size modified Rosenbrock method is used to conduct direct time integration upon this new set of first-order nonlinear ODEs. The mean axial speed and the amplitude of the speed variations, which are taken as bifurcation parameters, are varied, resulting in the bifurcation diagrams of Poincaré maps of the system. The dynamical characteristics of the system are examined more precisely via plotting time histories, phase-plane portraits, Poincaré sections, and fast Fourier transforms (FFTs)
Study of axial magnetic effect
International Nuclear Information System (INIS)
The Axial Magnetic Effect manifests itself as an equilibrium energy flow of massless fermions induced by the axial (chiral) magnetic field. Here we study the Axial Magnetic Effect in the quenched SU(2) lattice gauge theory with massless overlap fermions at finite temperature. We numerically observe that in the low-temperature hadron phase the effect is absent due to the quark confinement. In the high-temperature deconfinement phase the energy flow is an increasing function of the temperature which reaches the predicted asymptotic T2 behavior at high temperatures. We find, however, that energy flow is about one order of magnitude lower compared to a theoretical prediction
Characterization of Multiflux Axial Compressors
International Nuclear Information System (INIS)
In the present work the results of analytical models of performance are compared with experimental data acquired in the multi flux axial compressor test facility, built in The Pilcaniyeu Technological Complex for the SIGMA project.We describe the experimental circuit and the data of the dispersion inside the axial compressor obtained using a tracer gas through one of the annular inlets.The attained results can be used to validate the design code for the multi flux axial compressors and SIGMA industrial plant
NONLINEAR DYNAMICS OF AXIALLY ACCELERATING VISCOELASTIC BEAMS BASED ON DIFFERENTIAL QUADRATURE
Institute of Scientific and Technical Information of China (English)
Hu Ding; Liqun Chen
2009-01-01
This paper investigates nonlinear dynamical behaviors in transverse motion of an axially accelerating viscoelastic beam via the differential quadrature method. The governing equa-tion, a nonlinear partial-differential equation, is derived from the viscoelastic constitution relation using the material derivative. The differential quadrature scheme is developed to solve numeri-cally the governing equation. Based on the numerical solutions, the nonlinear dynamical behaviors presented in the case that the mean axial speed and the amplitude of the speed fluctuation are respectively varied while other parameters are fixed. The Lyapunov exponent and the initial value sensitivity of the different points of the beam, calculated from the time series based on the numer-ical solutions, are used to indicate periodic motions or chaotic motions occurring in the transverse motion of the axially accelerating viscoelastic beam.
Vacuum arc under axial magnetic fields: experimental and simulation research
International Nuclear Information System (INIS)
Axial magnetic field (AMF) technology is a most important control method of vacuum arc, particularly for high-current vacuum arcs in vacuum interrupters. In this paper, a review of the state of current research on vacuum arcs under AMF is presented. The major aspects of vacuum arc in an AMF such as arc voltage, the motion of cathode spots, and anode activities are discussed, and the most recent progress both of experimental and simulation research is presented. (topical review)
Multimode interaction in axially excited cylindrical shells
Directory of Open Access Journals (Sweden)
Silva F. M. A.
2014-01-01
Full Text Available Cylindrical shells exhibit a dense frequency spectrum, especially near the lowest frequency range. In addition, due to the circumferential symmetry, frequencies occur in pairs. So, in the vicinity of the lowest natural frequencies, several equal or nearly equal frequencies may occur, leading to a complex dynamic behavior. So, the aim of the present work is to investigate the dynamic behavior and stability of cylindrical shells under axial forcing with multiple equal or nearly equal natural frequencies. The shell is modelled using the Donnell nonlinear shallow shell theory and the discretized equations of motion are obtained by applying the Galerkin method. For this, a modal solution that takes into account the modal interaction among the relevant modes and the influence of their companion modes (modes with rotational symmetry, which satisfies the boundary and continuity conditions of the shell, is derived. Special attention is given to the 1:1:1:1 internal resonance (four interacting modes. Solving numerically the governing equations of motion and using several tools of nonlinear dynamics, a detailed parametric analysis is conducted to clarify the influence of the internal resonances on the bifurcations, stability boundaries, nonlinear vibration modes and basins of attraction of the structure.
Vectorial versus axial goldstone bosons
International Nuclear Information System (INIS)
The Yukawa interactions of fermions with Goldstone bosons are given in closed form for an arbitrary renormalizable field theory to all orders of perturbation theory or for a general effective Lagrangian. Although the diagonal couplings are always pseudoscalar there is an important difference between spontaneously broken vector and axial-vector global symmetries. Compared to the axial case, the diagonal douplings of 'vectorial' Goldstone bosons to charged fermions are suppressed by mixing angles or appear only via radiative corrections involving gauge fields. This general result may be relevant for the problem of flavour symmetry breaking in composite models. (Author)
Simulation of an Axial Vircator
Tikhomirov, V V
2013-01-01
An algorithm of particle-in-cell simulations is described and tested to aid further the actual design of simple vircators working on axially symmetric modes. The methods of correction of the numerical solution, have been chosen and jointly tested, allow the stable simulation of the fast nonlinear multiflow dynamics of virtual cathode formation and evolution, as well as the fields generated by the virtual cathode. The selected combination of the correction methods can be straightforwardly generalized to the case of axially nonsymmetric modes, while the parameters of these correction methods can be widely used to improve an agreement between the simulation predictions and the experimental data.
Rizzo, Giuseppe; Bonanno, Antonino; Massarotti, Giorgio Paolo; Pastorello, Luca; Raimondo, Mariarosa; Veronesi, Federico; Blosi, Magda
2016-01-01
Axial piston pumps and motors are widely used in heavy-duty applications and play a fundamental role in hydrostatic and power split drives. The mechanical power losses in hydraulic piston pumps come from the friction between parts in relative motion. The improvement, albeit marginal, in overall efficiency of these components may significantly impact the global efficiency of the machine. The friction between slipper and swash plate is a functional key in an axial piston pump, especially when t...
Nonlinear stability of cylindrical shells subjected to axial flow: Theory and experiments
Karagiozis, K. N.; Païdoussis, M. P.; Amabili, M.; Misra, A. K.
2008-01-01
This paper, is concerned with the nonlinear dynamics and stability of thin circular cylindrical shells clamped at both ends and subjected to axial fluid flow. In particular, it describes the development of a nonlinear theoretical model and presents theoretical results displaying the nonlinear behaviour of the clamped shell subjected to flowing fluid. The theoretical model employs the Donnell nonlinear shallow shell equations to describe the geometrically nonlinear structure. The clamped beam eigenfunctions are used to describe the axial variations of the shell deformation, automatically satisfying the boundary conditions and the circumferential continuity condition exactly. The fluid is assumed to be incompressible and inviscid, and the fluid-structure interaction is described by linear potential flow theory. The partial differential equation of motion is discretized using the Galerkin method and the final set of ordinary differential equations are integrated numerically using a pseudo-arclength continuation and collocation techniques and the Gear backward differentiation formula. A theoretical model for shells with simply supported ends is presented as well. Experiments are also described for (i) elastomer shells subjected to annular (external) air-flow and (ii) aluminium and plastic shells with internal water flow. The experimental results along with the theoretical ones indicate loss of stability by divergence with a subcritical nonlinear behaviour. Finally, theory and experiments are compared, showing good qualitative and reasonable quantitative agreement.
Axial structure of the nucleon
Energy Technology Data Exchange (ETDEWEB)
Veronique Bernard; Latifa Elouadrhiri; Ulf-G Meissner
2002-01-01
We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.
NONLINEAR DYNAMIC SIMULATION OF AN AXIALLY SLIDE-SPIN ROCKET FLEXIBLE SYSTEM WITH CLEARANCE
Institute of Scientific and Technical Information of China (English)
Zhu Huailiang; Zhang Fuxiang
2005-01-01
A hybrid approach is presented to investigate the dynamic behavior of an axially slide-spin flexible rocket with nonlinear clearance. The equations of motion of the flexible rocket are derived based upon Euler-Bernoulli beam theory and Hamilton principle and the finite element method. The characteristics of clearance between the spinning rocket and launcher are considered to be piecewise linear. Numerical solution is developed by direct integration method and demonstrates the validity of the method. The coupled dynamic behavior of axial motion and transverse vibrations of rocket are analyzed, and the influences of axially moving acceleration, spin speed, linking stiffness of elastic "shoes", and the nonlinearity of clearance on the motion attitude of rocket are studied.
STED microscopy based on axially symmetric polarized vortex beams
Zhehai, Zhou; Lianqing, Zhu
2016-03-01
A stimulated emission depletion (STED) microscopy scheme using axially symmetric polarized vortex beams is proposed based on unique focusing properties of such kinds of beams. The concept of axially symmetric polarized vortex beams is first introduced, and the basic principle about the scheme is described. Simulation results for several typical beams are then shown, including radially polarized vortex beams, azimuthally polarized vortex beams, and high-order axially symmetric polarized vortex beams. The results indicate that sharper doughnut spots and thus higher resolutions can be achieved, showing more flexibility than previous schemes based on flexible modulation of both phase and polarization for incident beams. Project supported by the National Natural Science Foundation of China (Grant Nos. 61108047 and 61475021), the Natural Science Foundation of Beijing, China (Grant No. 4152015), the Program for New Century Excellent Talents in Universities of China (Grant No. NCET-13-0667), and the Top Young Talents Support Program of Beijing, China (Grant No. CIT&TCD201404113).
Method to measure tone of axial and proximal muscle.
Gurfinkel, Victor S; Cacciatore, Timothy W; Cordo, Paul J; Horak, Fay B
2011-01-01
The control of tonic muscular activity remains poorly understood. While abnormal tone is commonly assessed clinically by measuring the passive resistance of relaxed limbs, no systems are available to study tonic muscle control in a natural, active state of antigravity support. We have developed a device (Twister) to study tonic regulation of axial and proximal muscles during active postural maintenance (i.e. postural tone). Twister rotates axial body regions relative to each other about the vertical axis during stance, so as to twist the neck, trunk or hip regions. This twisting imposes length changes on axial muscles without changing the body's relationship to gravity. Because Twister does not provide postural support, tone must be regulated to counteract gravitational torques. We quantify this tonic regulation by the restive torque to twisting, which reflects the state of all muscles undergoing length changes, as well as by electromyography of relevant muscles. Because tone is characterized by long-lasting low-level muscle activity, tonic control is studied with slow movements that produce "tonic" changes in muscle length, without evoking fast "phasic" responses. Twister can be reconfigured to study various aspects of muscle tone, such as co-contraction, tonic modulation to postural changes, tonic interactions across body segments, as well as perceptual thresholds to slow axial rotation. Twister can also be used to provide a quantitative measurement of the effects of disease on axial and proximal postural tone and assess the efficacy of intervention. PMID:22214974
Ion trajectory simulations of axial ac dipolar excitation in the Orbitrap
Wu, Guangxiang; Noll, Robert J.; Plass, Wolfgang R.; Hu, Qizhi; Perry, Richard H.; Cooks, R. Graham
2006-07-01
The newly developed version of the multi-particle ion trajectory simulation program, ITSIM 6.0, was applied to simulate ac dipolar excitation of ion axial motion in the Orbitrap. The Orbitrap inner and outer electrodes were generated in AutoCAD, a 3D drawing program. The electrode geometry was imported into the 3D field solver COMSOL; the field array was then imported into ITSIM 6.0. Ion trajectories were calculated by solving Newton's equations using Runge-Kutta integration methods. Compared to the analytical solution, calculated radial components of the field at the device's "equator" (z = 0) were within 0.5% and calculated axial components midway between the inner and outer electrodes were within 0.2%. The experiments simulated here involved the control of axial motion of ions in the Orbitrap by the application of dipolar ac signals to the split outer electrodes, as described in a recently published paper from this laboratory [Hu et al., J. Phys. Chem. A 110 (2006) 2682]. In these experiments, ac signal was applied at the axial resonant frequency of a selected ion. Axial excitation and eventual ion ejection resulted when the ac was in phase with, i.e., had 0° phase relative to ion axial motion. De-excitation of ion axial motion until the ions were at z = 0 and at rest with respect to the z-axis resulted if the applied ac was out of phase with ion motion, with re-excitation of ion axial motion occurring if the dipolar ac was continued beyond this point. Both de-excitation and re-excitation could be achieved mass-selectively and depended on the amplitude and duration (number of cycles) of the applied ac. The effects of ac amplitude, frequency, phase relative to ion motion, and bandwidth of applied waveform were simulated. All simulation results were compared directly with the experimental data and good agreement was observed. Such ion motion control experiments and their simulation provide the possibility to improve Orbitrap performance and to develop tandem mass
Axially symmetric rotating traversable wormholes
Kuhfittig, P K F
2003-01-01
This paper generalizes the static and spherically symmetric traversable wormhole geometry to a rotating axially symmetric one with a time-dependent angular velocity by means of an exact solution. It was found that the violation of the weak energy condition, although unavoidable, is considerably less severe than in the static spherically symmetric case. The radial tidal constraint is more easily met due to the rotation. Similar improvements are seen in one of the lateral tidal constraints. The magnitude of the angular velocity may have little effect on the weak energy condition violation for an axially symmetric wormhole. For a spherically symmetric one, however, the violation becomes less severe with increasing angular velocity. The time rate of change of the angular velocity, on the other hand, was found to have no effect at all. Finally, the angular velocity must depend only on the radial coordinate, confirming an earlier result.
View of the Axial Field Spectrometer
1980-01-01
The Axial Field Spectrometer, with the vertical uranium/scintillator calorimeter and the central drift chamber retracted for service. One coil of the Open Axial Field Magnet is just visible to the right.
Simulation of an Axial Vircator
Tikhomirov, V. V.; Siahlo, S. E.
2013-01-01
An algorithm of particle-in-cell simulations is described and tested to aid further the actual design of simple vircators working on axially symmetric modes. The methods of correction of the numerical solution, have been chosen and jointly tested, allow the stable simulation of the fast nonlinear multiflow dynamics of virtual cathode formation and evolution, as well as the fields generated by the virtual cathode. The selected combination of the correction methods can be straightforwardly gene...
Axial Force at the Vessel Bottom Induced by Axial Impellers
I. Fořt; P. Hasal; A. Paglianti; F. Magelli
2008-01-01
This paper deals with the axial force affecting the flat bottom of a cylindrical stirred vessel. The vessel is equipped with four radial baffles and is stirred with a four 45° pitched blade impeller pumping downwards. The set of pressure transducers is located along the whole radius of the flat bottom between two radial baffles. The radial distribution of the dynamic pressures indicated by the transducers is measured in dependence on the impeller off-bottom clearance and impeller speed.It fol...
Raunhardt, Daniel; Boulic, Ronan
2009-01-01
In this paper, we propose a hybrid postural control approach taking advantage of data-driven and goal-oriented methods while overcoming their limitations. In particular, we take advantage of the latent space characterizing a given motion database. We introduce a motion constraint operating in the latent space to benefit from its much smaller dimension compared to the joint space. This allows its transparent integration into a Prioritized Inverse Kinematics framework. If its priority is high t...
Free fall - A partial unique motion environment
Graybiel, A.
1980-01-01
Conditions leading to the elicitation of motion sickness have been divided into two main categories: partial motion environments, in which head movements are required to elicit motion sickness, and complete motion environments, in which independent movements of the head are not required for the production of symptoms. It is postulated that, according to this categorization, free fall constitutes a partial motion environment. In support of this hypothesis evidence is reviewed from Skylab missions, experiments in parabolic flight, and ground-based studies.
An Axial Sliding Test for machine elements surfaces
DEFF Research Database (Denmark)
Godi, Alessandro; Grønbæk, J.; Mohaghegh, Kamran;
2012-01-01
, a housing and a stripwound container. The rod and the sleeve are the two surfaces in relative sliding motion; the stripwound container maintains a constant, but adjustable normal pressure and the housing serves as interface between the sleeve and the container. For carrying out the test, two...... machineries are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the container advancement is found. Finally, preliminary tests are carried out involving a multifunctional...
Calculus of axial force in a mechanism using Lagrange equations
Directory of Open Access Journals (Sweden)
Thien Van NGUYEN
2016-06-01
Full Text Available Lagrange equations are used to study the motion of a system under the action of known external forces. Besides, based on these equations we can determine the internal force in an arbitrary element of the mechanism acting by active force. If an internal force has to be found, a supplementary mobility related to it is considered in the system. The corresponding internal force for new mobility is found for null values of mobility and of its first and second derivatives. Also the determination of the axial force in the connecting rod of the slider-crank mechanism is presented in this paper as an illustration of this method.
International Nuclear Information System (INIS)
The strange axial-vector mesons K1 (1270) and K1 (1400) are reanalyzed in the light of the updated experimental information and compared with the recent result on the Kππ production in τ decay. The mixing angle between the strange mesons of 3P1 and 1P1 is determined by the partial decay rates, and, independently, by the masses. They lead to θK∼33 degree or 57 degree. The observed K1 (1400) production dominance in the τ decay favors θK∼33 degree. Flavor-SU(3) breaking of 20% or so in the production amplitudes can explain quantitatively the observed production ratio
Inducing chaos by breaking axial symmetry in a black hole magnetosphere
Energy Technology Data Exchange (ETDEWEB)
Kopáček, O.; Karas, V., E-mail: kopacek@ig.cas.cz [Astronomical Institute, Academy of Sciences, Boční II, CZ-141 31 Prague (Czech Republic)
2014-06-01
While the motion of particles near a rotating, electrically neutral (Kerr), and charged (Kerr-Newman) black hole is always strictly regular, a perturbation in the gravitational or the electromagnetic field generally leads to chaos. The transition from regular to chaotic dynamics is relatively gradual if the system preserves axial symmetry, whereas non-axisymmetry induces chaos more efficiently. Here we study the development of chaos in an oblique (electro-vacuum) magnetosphere of a magnetized black hole. Besides the strong gravity of the massive source represented by the Kerr metric, we consider the presence of a weak, ordered, large-scale magnetic field. An axially symmetric model consisting of a rotating black hole embedded in an aligned magnetic field is generalized by allowing an oblique direction of the field having a general inclination with respect to the rotation axis of the system. The inclination of the field acts as an additional perturbation to the motion of charged particles as it breaks the axial symmetry of the system and cancels the related integral of motion. The axial component of angular momentum is no longer conserved and the resulting system thus has three degrees of freedom. Our primary concern within this contribution is to find out how sensitive the system of bound particles is to the inclination of the field. We employ the method of the maximal Lyapunov exponent to distinguish between regular and chaotic orbits and to quantify their chaoticity. We find that even a small misalignment induces chaotic motion.
Axial and transverse displacement tolerances during excimer laser surgery for myopia
Shimmick, John K.; Munnerlyn, Charles R.; Clapham, Terrance N.; McDonald, Marguerite B.
1991-06-01
This paper presents an analysis of the effects of axial and transverse displacement on the optical quality and accuracy of lenses created during excimer laser photoablation. Tolerance levels for axial positioning of the cornea prior to and during surgery are presented. The axial tolerance levels are dependent upon a number of parameters which include the intended dioptric correction and laser system cone angle. A collimation lens is introduced as a means of desensitizing the laser system to axial displacement. Transverse displacement tolerances during laser treatment are shown to depend upon the treatment diameter, dioptric correction and acceptable distortion level in the lens ablated into the anterior corneal stroma. A video and computer analysis of transverse motion during seven randomly selected excimer laser refractive surgeries is presented. Although transverse displacement exceeded the tolerance levels presented, it did not appear to affect the quality of correction in the eight patients analyzed.
Nonlinear Interactions between Slender Structures and Axial Flow
Du, Li
2015-03-01
For decades, dynamic behaviors of a slender structure with axial flow have been extensively studied. However, the governing equation based on expansions of small quantities is complicatedly-expressed and can be inappropriate as amplitude becomes considerably large. In this research, we are dedicated to finding an approach to study the nonlinear dynamics of a fluid-conveying slender strcture with arbitrary amplitude. By introducing the Intrinsic Coordinate, we find a concise way to describe the configuration of the system. Differential relations of such coordinate are studied and the rigorous nonlinear equation of motion is derived. Then rather than small-deflection approximation, linear dynamics are studied using Argand Diagram under a weaker condition named low-varying approximation. Nonlinear properties including Hopf bifurcation, limit-cycle motion and vibration frequencies are studied theoretically and experimentally.
Nonlinear flap-lag axial equations of a rotating beam
Kaza, K. R. V.; Kvaternik, R. G.
1977-01-01
It is possible to identify essentially four approaches by which analysts have established either the linear or nonlinear governing equations of motion for a particular problem related to the dynamics of rotating elastic bodies. The approaches include the effective applied load artifice in combination with a variational principle and the use of Newton's second law, written as D'Alembert's principle, applied to the deformed configuration. A third approach is a variational method in which nonlinear strain-displacement relations and a first-degree displacement field are used. The method introduced by Vigneron (1975) for deriving the linear flap-lag equations of a rotating beam constitutes the fourth approach. The reported investigation shows that all four approaches make use of the geometric nonlinear theory of elasticity. An alternative method for deriving the nonlinear coupled flap-lag-axial equations of motion is also discussed.
Institute of Scientific and Technical Information of China (English)
杨骁; 刘鑫
2008-01-01
Based on the mathematical model of the bending of the incompressible saturated poroelastic beam with axialdiffusion, the quasi-static bendings of the simply supported poroelastic beam subjected to a suddenly applied constant loadwere investigated, and the analytical solutions were obtained for different diffusion conditions of the pore fluid at the beamends. The deflections, the bending moments of the solid skeleton and the equivalent couples of the pore pressures werepresented in figures. It is also shown that the behavior of the saturated poroelastic beams depends closely on the diffusionconditions at the beam ends, especially for the equivalent couples of the pore pressures. It is found that the Mandel-Cryereffect also exists in the bending of the saturated poroelastic beams under specific diffusion conditions at the beam ends.
Axial Non-linear Dynamic Soil-Pile Interaction - Keynote
Directory of Open Access Journals (Sweden)
Holeyman A.
2014-01-01
Full Text Available This keynote lecture describes recent analytical and numerical advances in the modeling of the axial nonlinear dynamic interaction between a single pile and its embedding soil. On one hand, analytical solutions are developed for assessing the nonlinear axial dynamic response of the shaft of a pile subjected to dynamic loads, and in particular to vibratory loads. Radial inhomogeneity arising from shear modulus degradation is evaluated over a range of parameters and compared with those obtained by other authors and by a numerical radial discrete model simulating the pile and soil movements from integration of the laws of motion. New approximate non linear solutions for axial pile shaft behaviour developed from general elastodynamic equations are presented and compared to existing linear solutions. The soil non linear behaviour and its ability to dissipate mechanical energy upon cyclic loading are shown to have a significant influence on the mechanical impedance provided by the surrounding soil against pile shaft movement. The limitations of over-simplified modelling of pile response are highlighted.
Mass Effect on Axial Charge Dynamics
Guo, Er-dong
2016-01-01
We studied effect of finite quark mass on the dynamics of axial charge using the D3/D7 model in holography. The mass term in axial anomaly equation affects both the fluctuation (generation) and dissipation of axial charge. We studied the dependence of the effect on quark mass and external magnetic field. For axial charge generation, we calculated the mass diffusion rate, which characterizes the helicity flipping rate. The rate is a non-monotonous function of mass and can be significantly enhanced by the magnetic field. The diffusive behavior is also related to a divergent susceptibility of axial charge. For axial charge dissipation, we found that in the long time limit, the mass term dissipates all the charge effectively generated by parallel electric and magnetic fields. The result is consistent with a relaxation time approximation. The rate of dissipation through mass term is a monotonous increasing function of both quark mass and magnetic field.
Axial Vector $Z'$ and Anomaly Cancellation
Ismail, Ahmed; Tsao, Kuo-Hsing; Unwin, James
2016-01-01
Whilst the prospect of new $Z'$ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by constructing several motivated examples. Specifically, we consider axial vectors which couple universally to all SM fermions, as well as those which are generation-specific, leptophilic, and leptophobic. Anomaly cancellation typically requires the presence of new coloured and charged chiral fermions, and we argue that the masses of these new states must generally be comparable to that of the axial vector. Finally, an axial vector mediator could provide a portal between SM and hidden sector states, and we also consider the possibility that the axial vector couples to dark matter. If the dark matter relic density is set due to freeze-out via the axial vector, this strongly constrains the parameter space.
Axial velocity in decaying swirl flow
Algifri, A. H.; Bhardwaj, R. K.; Rao, Y. V. N.
1988-09-01
Experiments were carried out on turbulent swirling flow with variable initial swirl at different flow rates to study the effect of swirl on axial velocity. A correlation was made between the defect in the swirling flow axial velocity and the swirl number which locally defines the swirl intensity. An expression which can be used to predict the axial velocity distribution of turbulent swirling flow in a pipe is presented.
Sensorless Control of Axial Magnetic Bearings
Atsumo, Daichi; Yoshida, Toshiya; Ohniwa, Katsumi
This paper describes a sensorless control method of axial active magnetic bearings (AMBs). At high frequencies, inductance of the axial electromagnets is hardly dependent on the airgap because of the eddy current effects of the non-laminated core. Therefore the carrier frequency should be 3 kHz below to improve the sensitivity to the airgap. In the experiment, Sensorless controll of the axial AMBs have been achieved.
International Nuclear Information System (INIS)
The dynamical symmetry limit of the two-fluid Interacting Vector Boson Model (IVBM), defined through the chain Sp(12,R) contains U(3,3) contains Up(3) x Un(3) contains SU*(3) contains SO(3), is considered and applied for the description of nuclear collective spectra exhibiting axially asymmetric features. The effect of the introduction of a Majorana interaction to the SU*(3) model Hamiltonian on the γ-band energies is studied. The theoretical predictions are compared with the experimental data for 192Os, 190Os, and 112Ru isotopes. It is shown that by taking into account the full symplectic structures in the considered dynamical symmetry of the IVBM, the proper description of the energy spectra and the γ-band energy staggering of the nuclei under considerations can be achieved. The obtained results show that the potential energy surfaces for the following two nuclei 192Os and 112Ru, possess almost γ-flat potentials with very shallow triaxial minima, suggesting a more complex and intermediate situation between γ-rigid and γ-unstable structures. Additionally, the absolute B(E2) intraband transition probabilities between the states of the ground-state band and γ band, as well as the B(M1) interband transition probabilities between the states of the ground and γ bands for the two nuclei 192Os and 190Os are calculated and compared with experiment and for the B(E2) values with the predictions of some other collective models incorporating the γ-rigid or γ-unstable structures. The obtained results agree well with the experimental data and reveal the relevance of the used dynamical symmetry of IVBM in the description of nuclei exhibiting axially asymmetric features in their spectra. (orig.)
DEFF Research Database (Denmark)
Steijn, Arthur
2016-01-01
context, I have been conducting a practice-led research project. Central to the project is construction of a design model describing sets of procedures, concepts and terminology relevant for design and studies of motion graphics in spatial contexts. The focus of this paper is the role of model......Contemporary scenography often consists of video-projected motion graphics. The field is lacking in academic methods and rigour: descriptions and models relevant for the creation as well as in the analysis of existing works. In order to understand the phenomenon of motion graphics in a scenographic...... construction as a support to working systematically practice-led research project. The design model is being developed through design laboratories and workshops with students and professionals who provide feedback that lead to incremental improvements. Working with this model construction-as-method reveals...
Effective quantum number for axially symmetric problems
Trunov, N. N.
2014-01-01
We generalize the universal effective quantum number introduced earlier for centrally symmetric problems. The proposed number determines the semiclassical quantization condition for axially symmetric potentials.
Origin of axial current in scyllac
International Nuclear Information System (INIS)
The origin of the axial current observed in Scyllac (a high beta stellarator experiment) is discussed. A shaped coil and/or helical winding produce rotational transform which links magnetic lines of force to the plasma column and the axial current is induced electromagnetically. This phenomenon is inherent in a pulsed high-beta stellarator. The rotational transform produced by the induced axial current is much smaller than that associated with the l = 1, 0 equilibrium fields. The effect of the axial current on the equilibrium and stability of the plasma column is thus small. It is also shown that the magnetic field shear near a plasma surface is very strong
Directory of Open Access Journals (Sweden)
Gunzburg Robert
2006-04-01
the initial impulse acceleration response, subsequent multiple SMT impulses were found to produce significantly greater (3% to 25%, P Conclusion Knowledge of the vertebral motion responses produced by impulse-type, instrument-based adjusting instruments provide biomechanical benchmarks that support the clinical rationale for patient treatment. Our results indicate that impulse-type adjusting instruments that deliver multiple impulse SMTs significantly increase multi-axial spinal motion.
Searle, G. F. C.
2014-05-01
1. Elementary theory of harmonic motion; 2. Experimental work in harmonic motion; Experiment 1. Determination of g by a simple pendulum; Experiment 2. Harmonic motion of a body suspended by a spring; Experiment 3. Harmonic motion of a rigid body suspended by a torsion wire; Experiment 4. Study of a system with variable moment of inertia; Experiment 5. Dynamical determination of ratio of couple to twist for a torsion wire; Experiment 6. Comparison of the moments of inertia of two bodies; Experiment 7. Experiment with a pair of inertia bars; Experiment 8. Determination of the moment of inertia of a rigid pendulum; Experiment 9. Experiment on a pendulum with variable moment of inertia; Experiment 10. Determination of g by a rigid pendulum; Experiment 11. Pendulum on a yielding support; Experiment 12. Determination of the radius of curvature of a concave mirror by the oscillations of a sphere rolling in it; Experiment 13. Determination of g by the oscillations of a rod rolling on a cylinder; Experiment 14. Study of a vibrating system with two degrees of freedom; Note 1. On the vibration of a body suspended from a light spring; Note 2. Periodic time of a pendulum vibrating through a finite arc; Note 3. Periodic time for finite motion; Note 4. Periodic times of a pendulum with two degrees of freedom.
Axial forces and bending moments in the loaded rabbit tibia in vivo
Directory of Open Access Journals (Sweden)
Reifenrath Janin
2012-03-01
Full Text Available Abstract Background Different animal models are used as fracture models in orthopaedic research prior to implant use in humans, although biomechanical forces can differ to a great extend between species due to variable anatomic conditions, particularly with regard to the gait. The rabbit is an often used fracture model, but biomechanical data are very rare. The objective of the present study was to measure axial forces, bending moments, and bending axis directly in the rabbit tibia in vivo. The following hypothesis was tested: Axial forces and bending moments in the mid-diaphysis of rabbit tibia differ from other experimental animals or indirectly calculated data. Methods A minifixateur system with 4 force sensors was developed and attached to rabbit tibia (n = 4, which were subsequently ostectomised. Axial forces, bending moments and bending angles were calculated telemetrically during weight bearing in motion between 6 and 42 days post operation. Results Highest single values were 201% body weight [% bw] for axial forces and 409% bw cm for bending moments. Whereas there was a continous decrease in axial forces over time after day 10 (P = 0.03 on day 15, a decrease in bending moments was inconsistent (P = 0.03 on day 27. High values for bending moments were frequently, but not consistently, associated with high values for axial forces. Conclusion Axial forces in rabbit tibia exceeded axial forces in sheep, and differed from indirectly calculated data. The rabbit is an appropriate fracture model because axial loads and bending moments in rabbit tibia were more closely to human conditions than in sheep tibia as an animal model.
International Nuclear Information System (INIS)
The axial blanket fuel design in this program, which is retrofittable in operating pressurized water reactors, involves replacing the top and bottom of the enriched fuel column with low-enriched (less than or equal to 1.0 wt % 235U) fertile uranium. This repositioning of the fissile inventory in the fuel rod leads to decreased axial leakage and increased discharge burnups in the enriched fuel. Various axial blanket fuel designs, with blanket thicknesses from 0 to 10 inches and blanket enrichments from 0.2 to 1.0 wt % 235U, were investigated to determine the relationship between uranium utilization and power peaking. Analyses were preformed to assess the nuclear, mechanical, and thermal-hydraulic effects arising from the use of axial blankets. Four axial blanket lead test assemblies are being fabricated for scheduled irradiation in cycle 5 of Sacramento Municipal Utility District's Rancho Seco pressurized water reactor. Analyses to support licensing cycle 5 are in progress
Energy Technology Data Exchange (ETDEWEB)
Mayer, J.F.
1987-01-01
The present Part I of the final report covers theoretical investigations relating to the project; Part II presents the results of experimental work. The finite element method (FEM) is used to calculate the natural oscillation behaviour of coupled blade systems in axial-flow turbomachines. This involved combining the propagating wave method, which utilises the periodicity of such structures and substantially reduces computational effort, with existing FEM software systems (ASKA, PERMAS, NOVA). The static condition of pre-stress condition in the blades caused by the centrifugal force field and influencing the natural frequency can also be calculated by taking into account geometrically non-linear effects. Based on this condition, the equation of motion is linearised taking into account of centrifugal forces during oscillatory motion. When modelling a coupled blading, exceptions in respect of the forces and moments transmitted between the blade and the coupling element must be given special consideration. The natural frequencies obtained for different configurations and model formations are compared to resonance frequencies determined by experiments to support these coupling conditions. The discussion of natural oscillation modes of a model blading gives a deeper insight into the physical conditions of different types of coupled axial bladinngs. Based on the natural oscillation calculation of a real output stage blading,it is shown that the calculation method can also be used to analyse natural frequencies of complex structures. (orig.) With 80 figs., 12 tabs., 99 refs.
Czirok, A
1999-01-01
With the aim of understanding the emergence of collective motion from local interactions of organisms in a "noisy" environment, we study biologically inspired, inherently non-equilibrium models consisting of self-propelled particles. In these models particles interact with their neighbors by turning towards the local average direction of motion. In the limit of vanishing velocities this behavior results in a dynamics analogous to some Monte Carlo realization of equilibrium ferromagnets. However, numerical simulations indicate the existence of new types of phase transitions which are not present in the corresponding ferromagnets. In particular, here we demonstrate both numerically and analytically that even in certain one dimensional self-propelled particle systems an ordered phase exists for finite noise levels.
Structural support bracket for gas flow path
Energy Technology Data Exchange (ETDEWEB)
None
2016-08-02
A structural support system is provided in a can annular gas turbine engine having an arrangement including a plurality of integrated exit pieces (IEPs) forming an annular chamber for delivering gases from a plurality of combustors to a first row of turbine blades. A bracket structure is connected between an IEP and an inner support structure on the engine. The bracket structure includes an axial bracket member attached to an IEP and extending axially in a forward direction. A transverse bracket member has an end attached to the inner support structure and extends circumferentially to a connection with a forward end of the axial bracket member. The transverse bracket member provides a fixed radial position for the forward end of the axial bracket member and is flexible in the axial direction to permit axial movement of the axial bracket member.
Principal parametric resonance of axially accelerating rectangular thin plate in magnetic field
Institute of Scientific and Technical Information of China (English)
胡宇达; 张金志
2013-01-01
Nonlinear parametric vibration and stability is investigated for an axially accelerating rectangular thin plate subjected to parametric excitations resulting from the axial time-varying tension and axial time-varying speed in the magnetic field. Consid-ering geometric nonlinearity, based on the expressions of total kinetic energy, potential energy, and electromagnetic force, the nonlinear magneto-elastic vibration equations of axially moving rectangular thin plate are derived by using the Hamilton principle. Based on displacement mode hypothesis, by using the Galerkin method, the nonlinear para-metric oscillation equation of the axially moving rectangular thin plate with four simply supported edges in the transverse magnetic field is obtained. The nonlinear principal parametric resonance amplitude-frequency equation is further derived by means of the multiple-scale method. The stability of the steady-state solution is also discussed, and the critical condition of stability is determined. As numerical examples for an axially moving rectangular thin plate, the influences of the detuning parameter, axial speed, axial tension, and magnetic induction intensity on the principal parametric resonance behavior are investigated.
Stabilizing effects of ankle bracing under a combination of inversion and axial compression loading.
Tohyama, Harukazu; Yasuda, Kazunori; Beynnon, Bruce D; Renstrom, Per A
2006-04-01
The combined effects of bracing, axial compression and inversion rotation on the ankle-subtalar complexes were evaluated. Ex vivo tests under the load-controlled condition were performed on six cadaver ankle specimens using a six degree-of-freedom fixture. Inversion rotation was measured while subjecting the ankle-subtalar complex to a 2.5 N-m inversion moment and a combination of the testing variables (brace type, no brace, 178 N axial compression load, no compression load, 0 degrees and 20 degrees of plantar flexion) for a total of 16 tests per specimen. Three commercially available braces (two semirigid types and one lace up type) were evaluated. An axial compression load significantly decreased ankle-subtalar motion in unbraced ankles for the tested inversion moment. The contribution of bracing to stabilization of the ankle was smaller in the axial loading condition than in the no axial loading condition. The semirigid braces had greater stabilizing effects in response to the inversion moment than the lace up brace. Stabilizing effects of bracing were significantly greater in 20 degrees of plantar flexion than in 0 degrees of plantar flexion. The most common mechanism for an ankle sprain injury is inversion rotation on a weight-bearing ankle. Therefore, we should not overestimate stabilizing effects of bracing from evaluations of bracing without axial compression loading. PMID:15959767
Symbolic Modelling of Dynamic Human Motions
Stirling, David; Hesami, Amir; Ritz, Christian; Adistambha, Kevin; Naghdy, Fazel
2010-01-01
The results from Section 4 and Section 5 clearly support all of the three objectives discussed at the end of Section 2. These being to firstly; develop a plausible model for dynamic finger printing of motion data between individuals. Secondly, investigate a model that could to also identify distinctions between various motion tasks, and finally to formulate a model to identify motion pretence, or acting, as well as normal and (physically induced) abnormal motion behaviours.
Axial force measurement for esophageal function testing.
Gravesen, Flemming H; Funch-Jensen, Peter; Gregersen, Hans; Drewes, Asbjørn Mohr
2009-01-14
The esophagus serves to transport food and fluid from the pharynx to the stomach. Manometry has been the "golden standard" for the diagnosis of esophageal motility diseases for many decades. Hence, esophageal function is normally evaluated by means of manometry even though it reflects the squeeze force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external force transducers over in-vivo strain gauges of various sizes to electrical impedance based measurements. The amplitude and duration of the axial force has been shown to be as reliable as manometry. Normal, as well as abnormal, manometric recordings occur with normal bolus transit, which have been documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe with combined axial force and manometry recordings showed that axial force amplitude increased by 130% in contrast to an increase of 30% using manometry. Using axial force in combination with manometry provides a more complete picture of esophageal motility, and the current paper outlines the advantages of using this method. PMID:19132762
Axial force measurement for esophageal function testing
Institute of Scientific and Technical Information of China (English)
Flemming H Gravesen; Peter Funch-Jensen; Hans Gregersen; Asbjφrn Mohr Drewes
2009-01-01
The esophagus serves to transport food and fluid from the pharynx to the stomach. Manometry has been the "golden standard" for the diagnosis of esophageal motility diseases for many decades. Hence, esophageal function is normally evaluated by means of manometry even though it reflects the squeeze force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external force transducers over in-vivo strain gauges of various sizes to electrical impedance based measurements. The amplitude and duration of the axial force has been shown to be as reliable as manometry. Normal, as well as abnormal, manometric recordings occur with normal bolus transit, which have been documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe with combined axial force and manometry recordings showed that axial force amplitude increased by 130% in contrast to an increase of 30% using manometry. Using axial force in combination with manometry provides a more complete picture of esophageal motility, and the current paper outlines the advantages of using this method.
Axial length variability in cataract surgery
International Nuclear Information System (INIS)
To determine the mean axial length and biometric measures in patients undergoing cataract surgery and further compare the variability of axial length between the gender and with age. Study Design: Cross-sectional observational study. Place and Duration of Study: Eye Unit I, Department of Ophthalmology, Liaquat University of Medical and Health Sciences, Hyderabad, Pakistan from January 2010 to December 2012. Methodology: All patients referred for cataract surgery were assessed. The study included 886 eyes which were straightforward cataract cases with no other ocular problem. The data was collected for axial length, keratometric values and Intra-Ocular Lens (IOL) power prior to cataract surgery. The collected data was then analyzed using SPSS version 19 for windows software. Results: Gender based comparison showed significant difference in age, axial length, keratometric values and IOL power between the two groups (p=0.000). 86% of the eyes had an axial length between 21.00 mm and 23.99 mm. In univariate analysis there was significant (p=0.000) relation between overall age and axial length. The keratometric values ranged between 36.75 D and 52.50 D. Majority of the IOL powers ranged between 20.00 D and 23.00 D. Conclusion: The mean axial length of patients undergoing cataract surgery was 22.96 +- 1.04 mm, was comparable to Indian and Chinese population but shorter than the Western population. Females had shorter axial lengths, similar to other studies. Axial length was positively associated with age among the females, the cause of which is yet to be determined. (author)
Influence of constraints on axial growth reduction of cylindrical Li-ion battery electrode particles
Chakraborty, Jeevanjyoti; Please, Colin P.; Goriely, Alain; Chapman, S. Jonathan
2014-01-01
Volumetric expansion of silicon anode particles in a lithium-ion battery during charging may lead to the generation of undesirable internal stresses. For a cylindrical particle such growth may also lead to failure by buckling if the expansion is constrained in the axial direction due to other particles or supporting structures. To mitigate this problem, the possibility of reducing axial growth is investigated theoretically by studying simple modifications of the solid cylinder geometry. First...
The Buckling Analysis of Axially Loaded Columns with Artificial Neural Networks
Ülker, Mehmet; CİVALEK, Ömer
2002-01-01
The determination of effective design values in structural analysis is important.Axially loaded columns are designed according to the their buckling load capacity. In this study, a multi-layer artificial neural network is trained to give critical load for axially loaded columns and various support conditions. Back-propagation training algorithms are used considering the circular, square, rectangular, and I cross-sections. The artificial neural network, with is trained for circular and rec...
Energy Technology Data Exchange (ETDEWEB)
Tseng, Chia-Lin [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada); Sussman, Marshall S. [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Atenafu, Eshetu G. [Department of Biostatistics, University Health Network, University of Toronto, Toronto, Ontario (Canada); Letourneau, Daniel [Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada); Ma, Lijun [Department of Radiation Oncology, University of California San Francisco, San Francisco, California (United States); Soliman, Hany; Thibault, Isabelle [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Cho, B. C. John; Simeonov, Anna [Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada); Yu, Eugene [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Fehlings, Michael G. [Department of Neurosurgery and Spine Program, Toronto Western Hospital, University of Toronto, Toronto, Ontario (Canada); Sahgal, Arjun, E-mail: arjun.sahgal@sunnybrook.ca [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada)
2015-04-01
Purpose: To assess motion of the spinal cord and cauda equina, which are critical neural tissues (CNT), which is important when evaluating the planning organ-at-risk margin required for stereotactic body radiation therapy. Methods and Materials: We analyzed CNT motion in 65 patients with spinal metastases (11 cervical, 39 thoracic, and 24 lumbar spinal segments) in the supine position using dynamic axial and sagittal magnetic resonance imaging (dMRI, 3T Verio, Siemens) over a 137-second interval. Motion was segregated according to physiologic cardiorespiratory oscillatory motion (characterized by the average root mean square deviation) and random bulk shifts associated with gross patient motion (characterized by the range). Displacement was evaluated in the anteroposterior (AP), lateral (LR), and superior-inferior (SI) directions by use of a correlation coefficient template matching algorithm, with quantification of random motion measure error over 3 separate trials. Statistical significance was defined according to P<.05. Results: In the AP, LR, and SI directions, significant oscillatory motion was observed in 39.2%, 35.1%, and 10.8% of spinal segments, respectively, and significant bulk motions in all cases. The median oscillatory CNT motions in the AP, LR, and SI directions were 0.16 mm, 0.17 mm, and 0.44 mm, respectively, and the maximal statistically significant oscillatory motions were 0.39 mm, 0.41 mm, and 0.77 mm, respectively. The median bulk displacements in the AP, LR, and SI directions were 0.51 mm, 0.59 mm, and 0.66 mm, and the maximal statistically significant displacements were 2.21 mm, 2.87 mm, and 3.90 mm, respectively. In the AP, LR, and SI directions, bulk displacements were greater than 1.5 mm in 5.4%, 9.0%, and 14.9% of spinal segments, respectively. No significant differences in axial motion were observed according to cord level or cauda equina. Conclusions: Oscillatory CNT motion was observed to be relatively minor. Our results
International Nuclear Information System (INIS)
Purpose: To assess motion of the spinal cord and cauda equina, which are critical neural tissues (CNT), which is important when evaluating the planning organ-at-risk margin required for stereotactic body radiation therapy. Methods and Materials: We analyzed CNT motion in 65 patients with spinal metastases (11 cervical, 39 thoracic, and 24 lumbar spinal segments) in the supine position using dynamic axial and sagittal magnetic resonance imaging (dMRI, 3T Verio, Siemens) over a 137-second interval. Motion was segregated according to physiologic cardiorespiratory oscillatory motion (characterized by the average root mean square deviation) and random bulk shifts associated with gross patient motion (characterized by the range). Displacement was evaluated in the anteroposterior (AP), lateral (LR), and superior-inferior (SI) directions by use of a correlation coefficient template matching algorithm, with quantification of random motion measure error over 3 separate trials. Statistical significance was defined according to P<.05. Results: In the AP, LR, and SI directions, significant oscillatory motion was observed in 39.2%, 35.1%, and 10.8% of spinal segments, respectively, and significant bulk motions in all cases. The median oscillatory CNT motions in the AP, LR, and SI directions were 0.16 mm, 0.17 mm, and 0.44 mm, respectively, and the maximal statistically significant oscillatory motions were 0.39 mm, 0.41 mm, and 0.77 mm, respectively. The median bulk displacements in the AP, LR, and SI directions were 0.51 mm, 0.59 mm, and 0.66 mm, and the maximal statistically significant displacements were 2.21 mm, 2.87 mm, and 3.90 mm, respectively. In the AP, LR, and SI directions, bulk displacements were greater than 1.5 mm in 5.4%, 9.0%, and 14.9% of spinal segments, respectively. No significant differences in axial motion were observed according to cord level or cauda equina. Conclusions: Oscillatory CNT motion was observed to be relatively minor. Our results
New Anomaly of the Axial-Vector Current
Institute of Scientific and Technical Information of China (English)
HE Han-Xin
2001-01-01
By computing the axial-vector current operator equation, we find the anomalous axial-vector curl equation besides the well-known anomalous axial-vector divergence equation (the Adler-Bell-Jackiw anomaly) and discuss its implication.``
Evolution of Axially Symmetric Anisotropic Sources in $f(R,T)$ Gravity
Zubair, M
2015-01-01
We discuss the dynamical analysis in $f(R,T)$ gravity (where $R$ is Ricci scalar and $T$ is trace of energy momentum tensor) for gravitating sources carrying axial symmetry. The self gravitating system is taken to be anisotropic and line element describes axially symmetric geometry avoiding rotation about symmetry axis and meridional motions (zero vorticity case). The modified field equations for axial symmetry in $f(R,T)$ theory are formulated, together with the dynamical equations. Linearly perturbed dynamical equations lead to the evolution equation carrying adiabatic index $\\Gamma$ that defines impact of non-minimal matter to geometry coupling on range of instability for Newtonian (N) and post-Newtonian (pN) approximations.
Evolution of axially symmetric anisotropic sources in f(R, T) gravity
Energy Technology Data Exchange (ETDEWEB)
Zubair, M. [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Noureen, Ifra [University of Management and Technology, Department of Mathematics, Lahore (Pakistan)
2015-06-15
We discuss the dynamical analysis in f(R, T) gravity (where R is the Ricci scalar and T is the trace of the energy momentum tensor) for gravitating sources carrying axial symmetry. The self-gravitating system is taken to be anisotropic and the line element describes an axially symmetric geometry avoiding rotation about the symmetry axis and meridional motions (zero vorticity case). The modified field equations for axial symmetry in f(R, T) theory are formulated, together with the dynamical equations. Linearly perturbed dynamical equations lead to the evolution equation carrying the adiabatic index Γ, which defines the impact of a non-minimal matter to geometry coupling on the range of instability for Newtonian and post-Newtonian approximations. (orig.)
Computer axial tomography in geosciences
International Nuclear Information System (INIS)
Computer Axial Tomography (CAT) is one of the most adequate non-invasive techniques for the investigation of the internal structure of a large category of objects. Initially designed for medical investigations, this technique, based on the attenuation of X- or gamma-ray (and in some cases neutrons), generates digital images which map the numerical values of the linear attenuation coefficient of a section or of the entire volume of the investigated sample. Shortly after its application in medicine, CAT has been successfully used in archaeology, life sciences, and geosciences as well as for the industrial materials non-destructive testing. Depending on the energy of the utilized radiation as well as on the effective atomic number of the sample, CAT can provide with a spatial resolution of 0.01 - 0.5 mm, quantitative as well as qualitative information concerning local density, porosity or chemical composition of the sample. At present two types of axial Computer Tomographs (CT) are in use. One category, consisting of medical as well as industrial CT is equipped with X-ray tubes while the other uses isotopic gamma-ray sources. CT provided with intense X-ray sources (equivalent to 12-15 kCi or 450-550 TBq) has the advantage of an extremely short running time (a few seconds and even less) but presents some disadvantages known as beam hardening and absorption edge effects. These effects, intrinsically related to the polychromatic nature of the X-rays generated by classical tubes, need special mathematical or physical corrections. A polychromatic X-ray beam can be made almost monochromatic by means of crystal diffraction or by using adequate multicomponent filters, but these devices are costly and considerably diminish the output of X-ray generators. In the case of CT of the second type, monochromatic gamma-rays generated by radioisotopic sources, such as 169 Yb (50.4 keV), 241 Am (59 keV), 192 Ir (310.5 and 469.1 keV ) or 137 Cs (662.7 keV), are used in combination with
Nonperturbative features of the axial current
Kopeliovich, B Z; Siddikov, M
2013-01-01
In this paper we study the nonperturbative structure of the axial current and evaluate the two-point distribution amplitudes $\\int d\\xi\\, e^{-iq...\\xi}$ in the framework of the instanton vacuum model in the leading order in $\\mathcal{O}(N_{c})$. We perform a direct numerical test of the relations between the axial current and the pion distribution amplitudes, imposed by PCAC, and found excellent agreement.
Axial Vircator for Electronic Warfare Applications
L. Drazan; R. Vrana
2009-01-01
This paper deals with a high power microwave generator with virtual cathode – vircator in axial release for electronic warfare applications. The classification of directed energy weapons microwave (DEWM) is introduced together with basic block diagrams of a particular class of DEWM. In the paper, methods for designing vircator pulsed power supply, axial vircator structure, measurement methods and experimental results are presented. The vircator in electromagnetic ammunition is powered b...
Nonperturbative Aspects of Axial Vector Vertex
Institute of Scientific and Technical Information of China (English)
ZONG Hong-Shi; CHEN Xiang-Song; WANG Fan; CHANG Chao-Hsi; ZHAO En-Guang
2002-01-01
It is shown how the axial vector current of current quarks is related to that of constituent quarks within the framework of the global color symmetry model.Gluon dressing of the axial vector vertex and the quark self-energy functions are described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger Dyson equation in the rainbow approximation,respectively.
Institute of Scientific and Technical Information of China (English)
王金剑; 王寅; 朱小蕾
2012-01-01
Molecular dynamics (MD) simulations are carried out with Born-Mayer-Huggins and Lennard-Jones interaction potentials.We investigate the motion characteristics of KI nanoparticles attached on the outside of carbon nanotubes ( CNTs) with temperature gradient ( V T).The results demonstrate that there are two kinds of motion modes during KI nanoparticles move from the hot zone to the cold zone of the CNTs.Through the analysis of the trajectory of KI nanoparticles supported on the CNTs subject to temperature gradient,we find the shape of the moving route are affected by the chirality,diameter,and temperature gradient of CNT.The analysis of the force added on KI nanoparticles supported on the CNTs with temperature gradient can account for the relationship between the motion modes of KI nanoparticles and the chirality of CNT.The results of this article may be instructive in designing of novel nanoscale motors.%采用分子动力学(MD)模拟的方法,使用Born-Mayer-Huggins与Lennard-Jones相互作用势函数,研究KI纳米粒子负载在具有一定温度梯度的碳纳米管外壁上的运动特征.模拟结果表明,在纳米粒子由碳管高温端向低温端运动的过程中有两种模式.通过KI纳米粒子在具有温度梯度的碳管上的轨迹分析,说明了这些运动模式与碳纳米管的手性、管径和温度梯度的大小密切相关.通过KI纳米粒子在具有温度梯度的碳管上的受力分析,解释了KI纳米粒子在具有温度梯度的碳管上采取特殊模式运动的原因.本文的工作对于设计纳米尺度的马达有一定的指导意义.
An Unbroken Axial Vector Current Conservation Law
Sharafiddinov, Rasulkhozha S
2015-01-01
The mass, energy and momentum of the neutrino of a true flavor have an axial-vector nature. As a consequence, the left-handed truly neutral neutrino in an axial-vector field of emission can be converted into a right-handed one and vice versa. This predicts the unidenticality of masses, energies and momenta of neutrinos of the different components. Recognizing such a difference in masses, energies, momenta and accepting that the left-handed axial-vector neutrino and the right-handed antineutrino of true neutrality refer to long-lived C-odd leptons, and the right-handed truly neutral neutrino and the left-handed axial-vector antineutrino are of short-lived fermions of C-oddity, we would write a new CP-even Dirac equation taking into account the flavor symmetrical axial-vector mass, energy and momentum matrices. Their presence explains the spontaneous mirror symmetry violation, confirming that an axial-vector current conservation law has never violated. They reflect the availability of a mirror Minkowski space i...
Hamilton's equations for a fluid membrane: axial symmetry
International Nuclear Information System (INIS)
Consider a homogeneous fluid membrane, or vesicle, described by the Helfrich-Canham energy, quadratic in the mean curvature. When the membrane is axially symmetric, this energy can be viewed as an 'action' describing the motion of a particle; the contours of equilibrium geometries are identified with particle trajectories. A novel Hamiltonian formulation of the problem is presented which exhibits the following two features: (i) the second derivatives appearing in the action through the mean curvature are accommodated in a natural phase space and (ii) the intrinsic freedom associated with the choice of evolution parameter along the contour is preserved. As a result, the phase space involves momenta conjugate not only to the particle position but also to its velocity, and there are constraints on the phase space variables. This formulation provides the groundwork for a field theoretical generalization to arbitrary configurations, with the particle replaced by a loop in space
No spreading across the southern Juan de Fuca ridge axial cleft during 1994-1996
Chadwell, C.D.; Hildebrand, J.A.; Spiess, Fred N.; Morton, J.L.; Normark, W.R.; Reiss, C.A.
1999-01-01
Direct-path acoustic measurements between seafloor transponders observed no significant extension (-10 ?? 14 mm/yr) from August 1994 to September 1996 at the southern Juan de Fuca Ridge (44??40' N and 130??20' W). The acoustic path for the measurement is a 691-m baseline straddling the axial cleft, which bounds the Pacific and Juan de Fuca plates. Given an expected full-spreading rate of 56 mm/yr, these data suggest that extension across this plate boundary occurs episodically within the narrow (~1 km) region of the axial valley floor, and that active deformation is occurring between the axial cleft and the plate interior. A cleft-parallel 714-m baseline located 300 m to the west of the cleft on the Pacific plate monitored system performance and, as expected, observed no motion (+5??7 mm/yr) between the 1994 and 1996 surveys.Direct-path acoustic measurements between seafloor transponders observed no significant extension (-10 ?? 14 mm/yr) from August 1994 to September 1996 at the southern Juan de Fuca Ridge (44??40 minutes N and 130??20 minutes W). The acoustic path for the measurement is a 691-m baseline straddling the axial cleft, which bounds the Pacific and Juan de Fuca plates. Given an expected full-spreading rate of 56 mm/yr, these data suggest that extension across this plate boundary occurs episodically within the narrow (approx. 1 km) region of the axial valley floor, and that active deformation is occurring between the axial cleft and the plate interior. A cleft-parallel 714-m baseline located 300 m to the west of the cleft on the Pacific plate monitored system performance and, as expected, observed no motion (+5 ?? 7 mm/yr) between the 1994 and 1996 surveys.
Molecular dynamics study of nanojoining between axially positioned Ag nanowires
Cui, Jianlei; Theogene, Barayavuga; Wang, Xuewen; Mei, Xuesong; Wang, Wenjun; Wang, Kedian
2016-08-01
The miniaturization of electronics devices into nanometer scale is indispensable for next-generation semiconductor technology. Ag nanowires (Ag NWs) are considered to be the promising candidates for future electronic circuit owing to the excellent electrical and thermal properties. The nanojoining of axially positioned Ag NWs was performed by molecular dynamics simulation. Through the detailed atomic evolution during the nanojoining, the results indicate that the temperature and the distance between Ag NWs in axial direction have a great impact on nanojoining effect. When the nanojoining temperature is relatively high, the atoms are disordered and the atomic queues become to distort with strong thermodynamic properties and weak effect of metal bonds. At the relatively low temperature, the Ag NWs can be well connected with good junction quality and their own morphology, which is similar to the cold welding without fusion, while the distance between Ag NWs should be controlled for interaction and diffusion of interfacial atoms at nanowires head. When the Ag NWs are placed on Si and SiO2 substrate, because the atomic species and lattice structure of substrate material can differently affect the motions of Ag atoms through the interactive force between the atoms, the nanojoining quality of Ag NWs on Si substrate is better than that on the SiO2 substrate. So, for getting effective and reliable nanojoining without nanosolders and other materials, the temperature, distance and substrate surface should be reasonably controlled and selected, providing helpful theoretical guidance for experiment and application of nanojoining.
A microscopic derivation of nuclear collective rotation-vibration model, axially symmetric case
Gulshani, Parviz
2015-01-01
We derive a microscopic version of the successful phenomenological hydrodynamic model of Bohr-Davydov-Faessler-Greiner for collective rotation-vibration motion of an axially symmetric deformed nucleus. The derivation is not limited to small oscillation amplitude. The nuclear Schrodinger equation is canonically transformed the to collective co-ordinates, which is then linearized using a constrained variational method. The associated constraints are imposed on the wavefunction rather than on th...
Comparison of ISO Standard and TKR Patient Axial Force Profiles during the Stance Phase of Gait
Lundberg, Hannah J.; Ngai, Valentina; Markus A. Wimmer
2012-01-01
Preclinical endurance testing of total knee replacements (TKRs) is performed using International Organization for Standardization (ISO) load and motion protocols. The standards are based on data from normal subjects and may not sufficiently mimic in vivo implant conditions. In this study, a mathematical model was used to calculate the axial force profile of 30 TKR patients with two current implant types, 22 with NexGen and eight with Miller-Galante II Cruciate-Retaining TKRs, and statisticall...
Auditory motion capturing ambiguous visual motion
Directory of Open Access Journals (Sweden)
ArjenAlink
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.
Energy Technology Data Exchange (ETDEWEB)
Pechstein, Astrid, E-mail: astrid.pechstein@jku.at [Johannes Kepler University Linz, Institute of Technical Mechanics (Austria); Gerstmayr, Johannes, E-mail: johannes.gerstmayr@accm.co.at [Austrian Center of Competence in Mechatronics (Austria)
2013-10-15
In the scope of this paper, a finite-element formulation for an axially moving beam is presented. The beam element is based on the absolute nodal coordinate formulation, where position and slope vectors are used as degrees of freedom instead of rotational parameters. The equations of motion for an axially moving beam are derived from generalized Lagrange equations in a Lagrange-Eulerian sense. This procedure yields equations which can be implemented as a straightforward augmentation to the standard equations of motion for a Bernoulli-Euler beam. Moreover, a contact model for frictional contact between an axially moving strip and rotating rolls is presented. To show the efficiency of the method, simulations of a belt drive are presented.
Directory of Open Access Journals (Sweden)
Gianluca Borgese
2015-07-01
Full Text Available This work illustrates a complete design flow of an electronic system developed to support applications in which there are the need to measure motion parameters and transmit them to a remote unit for real-time teleprocessing. In order to be useful in many operative contexts, the system is flexible, compact, and lightweight. It integrates a tri-axial inertial sensor, a GPS module, a wireless transceiver and can drive a pocket camera. Data acquisition and packetization are handled in order to increase data throughput on Radio Bridge and to minimize power consumption. A trajectory reconstruction algorithm, implementing the Kalman-filter technique, allows obtaining real-time body tracking using only inertial sensors. Thanks to a graphical user interface it is possible to remotely control the system operations and to display the motion data.
Axial and radial velocities in the creeping flow in a pipe
Directory of Open Access Journals (Sweden)
Zuykov Andrey L'vovich
2014-05-01
Full Text Available The article is devoted to analytical study of transformation fields of axial and radial velocities in uneven steady creeping flow of a Newtonian fluid in the initial portion of the cylindrical channel. It is shown that the velocity field of the flow is two-dimensional and determined by the stream function. The article is a continuation of a series of papers, where normalized analytic functions of radial axial distributions in uneven steady creeping flow in a cylindrical tube with azimuthal vorticity and stream function were obtained. There is Poiseuille profile for the axial velocity in the uniform motion of a fluid at an infinite distance from the entrance of the pipe (at x = ∞, here taken equal to zero radial velocity. There is uniform distribution of the axial velocity in the cross section at the tube inlet at x = 0, at which the axial velocity is constant along the current radius. Due to the axial symmetry of the flow on the axis of the pipe (at r = 0, the radial velocities and the partial derivative of the axial velocity along the radius, corresponding to the condition of the soft function extremum, are equal to zero. The authors stated vanishing of the velocity of the fluid on the walls of the pipe (at r = R , where R - radius of the tube due to its viscous sticking and tightness of the walls. The condition of conservation of volume flow along the tube was also accepted. All the solutions are obtained in the form of the Fourier - Bessel. It is shown that the hydraulic losses at uniform creeping flow of a Newtonian fluid correspond to Poiseuille - Hagen formula.
2013-01-01
Please note this is a short discount publication. In today's manufacturing environment, Motion Control plays a major role in virtually every project.The Motion Control Report provides a comprehensive overview of the technology of Motion Control:* Design Considerations* Technologies* Methods to Control Motion* Examples of Motion Control in Systems* A Detailed Vendors List
Echocardiographic Evaluation of the Jarvik 2000 Axial-Flow LVAD
Stainback, Raymond F.; Croitoru, Mihai; Hernandez, Antonieta; Myers, Timothy J.; Wadia, Yasmin; Frazier, O H
2005-01-01
From April 2000 through September 2001, we studied 11 patients with the Jarvik 2000 —a left ventricular assist device with an axial-flow pump that provides continuous blood flow—to determine the echocardiographic characteristics. All patients underwent complete echocardiographic examination, including outflow-graft flow evaluation 24 hours after implantation and each month thereafter for the duration of support. Data were obtained at each pump setting (8,000–12,000 rpm in 1,000-rpm increments...
Optimization of residual heat removal pump axial thrust and axial bearing
Energy Technology Data Exchange (ETDEWEB)
Schubert, F.
1996-12-01
The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies.
Polarization converters based on axially symmetric twisted nematic liquid crystal.
Ko, Shih-Wei; Ting, Chi-Lun; Fuh, Andy Y-G; Lin, Tsung-Hsien
2010-02-15
An axially symmetric twisted nematic liquid crystal (ASTNLC) device, based on axially symmetric photoalignment, was demonstrated. Such an ASTNLC device can convert axial (azimuthal) to azimuthal (axial) polarization. The optical properties of the ASTNLC device are analyzed and found to agree with simulation results. The ASTNLC device with a specific device can be adopted as an arbitrary axial symmetric polarization converter or waveplate for axially, azimuthally or vertically polarized light. A design for converting linear polarized light to axially symmetric circular polarized light is also demonstrated. PMID:20389369
Improving the lattice axial vector current
Horsley, R; Perlt, H; Rakow, P E L; Schierholz, G; Schiller, A; Zanotti, J M
2015-01-01
For Wilson and clover fermions traditional formulations of the axial vector current do not respect the continuum Ward identity which relates the divergence of that current to the pseudoscalar density. Here we propose to use a point-split or one-link axial vector current whose divergence exactly satisfies a lattice Ward identity, involving the pseudoscalar density and a number of irrelevant operators. We check in one-loop lattice perturbation theory with SLiNC fermion and gauge plaquette action that this is indeed the case including order $O(a)$ effects. Including these operators the axial Ward identity remains renormalisation invariant. First preliminary results of a nonperturbative check of the Ward identity are also presented.
Axial instability of rotating relativistic stars
Friedman, J L; Friedman, John L.; Morsink, Sharon M.
1998-01-01
Perturbations of rotating relativistic stars can be classified by their behavior under parity. For axial perturbations (r-modes), initial data with negative canonical energy is found with angular dependence $e^{im\\phi}$ for all values of $m\\geq 2$ and for arbitrarily slow rotation. This implies instability (or marginal stability) of such perturbations for rotating perfect fluids. This low $m$-instability is strikingly different from the instability to polar perturbations, which sets in first for large values of $m$. The timescale for the axial instability appears, for small angular velocity $\\Omega$, to be proportional to a high power of $\\Omega$. As in the case of polar modes, viscosity will again presumably enforce stability except for hot, rapidly rotating neutron stars. This work complements Andersson's numerical investigation of axial modes in slowly rotating stars.
The axial distribution of reactivity coefficients
International Nuclear Information System (INIS)
The purpose of the present work is to investigate the correlation of the axial distributions of the different reactivity coefficients with the neutron flux and the neutron flux squared. Calculations were carried out for the Zion Unit 2 PWR. Reactivity coefficients, forward fluxes and adjoint fluxes were all computed and correlations obtained. The core length was divided into 7 axial regions in order to obtain the effect on reactivity in the reactor as a whole of changing the cross sections in each axial region in turn. The parameters chosen for change were coolant density, coolant temperature and fuel temperature. The results appear to bear out our original hypothesis that the reactivity coefficient profiles have a higher positive correlation with the total flux squared profile than with the linear flux profile. (authors). 5 refs., 2 figs
Institute of Scientific and Technical Information of China (English)
贾宏宇; 郑史雄
2013-01-01
为解决传统的虚拟激励法多维多点虚拟激励荷载输入繁琐及在通用有限元软件中实现困难的问题,通过在质量矩阵上“置大数”的方法快速实现地震动输入,更快捷地将一维多点激励扩展到多维多点虚拟激励,运用绝对位移直接求解运动方程.相比传统的多维多点虚拟激励法,不必将绝对位移分解为拟静力位移项和动力相对位移项,避免了求解静力影响矩阵的繁琐,能更高效的实现多自由度大跨结构多维多点虚拟激励荷载在通用有限元软件中的输入与分析,不需要编制专门的计算程序,使得虚拟激励法在理论上和工程中的应用得到进一步的拓展.%This work is concerned with the input and implementation issues of the pseudo load in the finite element software for a pseudo excitation method. The input of ground motion is achieved more expediently through a "place large numbers" approach. Therefore, the pseudo excitation is swiftly extended from one-dimensional and multi-supports (ODMS) to multi-dimensional and multi-supports (MDMS), and the motion equations are solved directly through absolute displacement. Compared to the traditional MDMS pseudo excitation method, the directly-solving method through the absolute displacement does not decompose the absolute displacement into quasi-static and dynamic relative displacement items, avoids solving the static influence matrix, more efficiently realizes the input of pseudo excitation loading and the analysis of multiple-degree-of-freedom structures in the finite element software, and does not require a special program. The pseudo excitation method is further expanded in theory and engineering applications.
Mould, R A
2003-01-01
Preciously given rules allow conscious systems to be included in quantum mechanical systems. There rules are derived from the empirical experience of an observer who witnesses a quantum mechanical interaction leading to the capture of a single particle. In the present paper it is shown that purely classical changes experienced by an observer are consistent with these rules. Three different interactions are considered, two of which combine classical and quantum mechanical changes. The previously given rules support all of these cases. Key Words: brain states, conscious observer, detector, measurement, probability current, state reduction, von Neumann, wave collapse.
Selection rules and ratios for axial couplings
Buccella, F; Pugliese, A; Sorace, E
1972-01-01
The predictions for the axial couplings following from the use of the mixing operator U(Z), previously introduced to tilt the axial charges of SU/sub 6/ in the physical ones, are studied. The quantum number (-1)/sup L+L3/, where L and L/sub 3/ are the O/sub 3/ angular momentum and its third component, is shown to be conserved. From the properties of Z further predictions can be achieved as the D/F= /sup 3///sub 2/ for the /sup 1///sub 2//sup +/ baryon octet in general agreement with experiment. (14 refs).
Axial Stiffness of Multiwalled Carbon Nanotubes
Zavalniuk, Vladimir
2011-01-01
The axial stiffness of MWCNTs is demonstrated to be determined only by several external shells (usually 3-5 and up to 15 for the extremely large nanotubes and high elongations) what is in a good agreement with experimentally observed inverse relation between the radius and Young modulus (i.e., stiffness) of MWCNTs. This result is a consequence of the van der Waals intershell interaction. The interpolating formula is obtained for the actual axial stiffness of MWCNT as a function of the tube ex...
Axial Vircator for Electronic Warfare Applications
Directory of Open Access Journals (Sweden)
L. Drazan
2009-12-01
Full Text Available This paper deals with a high power microwave generator with virtual cathode – vircator in axial release for electronic warfare applications. The classification of directed energy weapons microwave (DEWM is introduced together with basic block diagrams of a particular class of DEWM. In the paper, methods for designing vircator pulsed power supply, axial vircator structure, measurement methods and experimental results are presented. The vircator in electromagnetic ammunition is powered by magneto-cumulative generator and in weapons for defense of objects (WDO, it is powered by Marx generator. The possible applications of a vircator in the DEWM area are discussed.
Motion of rotor supported on aerodynamic bearings
Czech Academy of Sciences Publication Activity Database
Půst, Ladislav; Šimek, J.; Kozánek, Jan
Praha : Institute of Thermomechanics AS CR, v. v. i., 2007 - (Zolotarev, I.), s. 235-236 ISBN 978-80-87012-06-2. [Engineering Mechanics 2007: national conference with international participation. Svratka (CZ), 14.05.2007-17.05.2007] R&D Projects: GA ČR GA101/06/1787 Institutional research plan: CEZ:AV0Z20760514 Keywords : rotor dynamics * aerodynamic bearing * tilting pad s Subject RIV: BI - Acoustics
STABILITY AND LOCAL BIFURCATION IN A SIMPLY-SUPPORTED BEAM CARRYING A MOVING MASS
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The stability and local bifurcation of a simply-supported flexible beam (Bernoulli-Euler type) carrying a moving mass and subjected to harmonic axial excitation are investigated.In the theoretical analysis, the partial differential equation of motion with the fifth-order nonlinear term is solved using the method of multiple scales (a perturbation technique). The stability and local bifurcation of the beam are analyzed for 1/2 sub harmonic resonance. The results show that some of the parameters, especially the velocity of moving mass and external excitation, affect the local bifurcation significantly. Therefore, these parameters play important roles in the system stability.
Breast motion asymmetry during running
Mills, Chris; Risius, Debbie; Scurr, Joanna
2015-01-01
Breast asymmetry is common in females, despite a similar driving force; dynamic activity may result in asymmetrical breast motion. This preliminary study investigated how breast categorisation (left/right or dominant/non-dominant) may affect breast support recommendations and its relationship with breast pain. Ten females ran on a treadmill at 10 kph in three breast supports (no bra, everyday bra, sports bra). Five reflective markers on the thorax and nipples were tracked using infrared camer...
Recommendations for Addressing Axial Burnup in the PWR Burnup Credit Analyses
Energy Technology Data Exchange (ETDEWEB)
Wagner, J.C.
2002-10-23
This report presents studies performed to support the development of a technically justifiable approach for addressing the axial-burnup distribution in pressurized-water reactor (PWR) burnup-credit criticality safety analyses. The effect of the axial-burnup distribution on reactivity and proposed approaches for addressing the axial-burnup distribution are briefly reviewed. A publicly available database of profiles is examined in detail to identify profiles that maximize the neutron multiplication factor, k{sub eff}, assess its adequacy for PWR burnup credit analyses, and investigate the existence of trends with fuel type and/or reactor operations. A statistical evaluation of the k{sub eff} values associated with the profiles in the axial-burnup-profile database was performed, and the most reactive (bounding) profiles were identified as statistical outliers. The impact of these bounding profiles on k{sub eff} is quantified for a high-density burnup credit cask. Analyses are also presented to quantify the potential reactivity consequence of loading assemblies with axial-burnup profiles that are not bounded by the database. The report concludes with a discussion on the issues for consideration and recommendations for addressing axial burnup in criticality safety analyses using burnup credit for dry cask storage and transportation.
Knowledge Based Design of Axial Flow Compressor
Directory of Open Access Journals (Sweden)
Dinesh kumar.R
2015-05-01
Full Text Available In the aerospace industry with highly competitive market the time to design and delivery is shortening every day. Pressure on delivering robust product with cost economy is in demand in each development. Even though technology is older, it is new for each customer requirement and highly non-liner to fit one in another place. Gas turbine is considered one of a complex design in the aircraft system. It involves experts to be grouped with designers of various segments to arrive the best output. The time is crucial to achieve a best design and it needs knowledge automation incorporated with CAD/CAE tools. In the present work an innovative idea in the form of Knowledge Based Engineering for axial compressor is proposed, this includes the fundamental design of axial compressor integrated with artificial intelligence in the form of knowledge capturing and programmed with high level language (Visual Basis.Net and embedded into CATIA v5. This KBE frame work eases out the design and modeling of axial compressor design and produces 3D modeling for further flow simulation with fluid dynamic in Ansys-Fluent. Most of the aerospace components are developed through simulation driven product development and in this case it is established for axial compressor.
The Axial Current in Electromagnetic Interaction
Cheoun, M K; Cheon, I T; Cheoun, Myung Ki; Cheon, Il-Tong
1998-01-01
We discussed the possibility that the charged axial currents of matter fields could be non-conserved in electromagnetic interaction at $O(e) $ order. It means that chiral symmetry is broken explicitly by electromagnetic interaction. This explicit symmetry breaking of chiral symmetry is shown to lead the mass differences between the charged and neutral particles of matter fields.
Constant-axial-intensity nondiffracting beam.
Cox, A J; D'Anna, J
1992-02-15
Numerical solutions of the Fresnel diffraction integral with various apodizing filter functions are used to indicate that a so-called nondiffracting beam can be produced that maintains a constant spot size and constant axial intensity over a considerable range, approximately 30 m in our example. PMID:19784285
Axially symmetric SU(3) gravitating skyrmions
Energy Technology Data Exchange (ETDEWEB)
Ioannidou, Theodora [Maths Division, School of Technology, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece)]. E-mail: ti3@auth.gr; Kleihaus, Burkhard [Institut fuer Physik, Universitaet Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany)]. E-mail: kleihaus@theorie.physik.uni-oldenburg.de; Zakrzewski, Wojtek [Department of Mathematical Sciences, University of Durham, Durham DH1 3LE (United Kingdom)]. E-mail: w.j.zakrzewski@durham.ac.uk
2004-10-21
Axially symmetric gravitating multi-skyrmion configurations are obtained using the harmonic map ansatz introduced in [J. Math. Phys. 40 (1999) 6353]. In particular, the effect of gravity on the energy and baryon densities of the SU(3) non-gravitating multi-skyrmion configurations is studied in detail.
Axially symmetric SU(3) Gravitating Skyrmions
Ioannidou, T A; Zakrzewski, W J; Ioannidou, Theodora; Kleihaus, Burkhard; Zakrzewski, Wojtek
2004-01-01
Axially symmetric gravitating multi-skyrmion configurations are obtained using the harmonic map ansatz introduced in [1]. In particular, the effect of gravity on the energy and baryon densities of the SU(3) non-gravitating multi-skyrmion configurations is studied in detail.
Axially symmetric SU(3) gravitating skyrmions
International Nuclear Information System (INIS)
Axially symmetric gravitating multi-skyrmion configurations are obtained using the harmonic map ansatz introduced in [J. Math. Phys. 40 (1999) 6353]. In particular, the effect of gravity on the energy and baryon densities of the SU(3) non-gravitating multi-skyrmion configurations is studied in detail
Primitive axial algebras of Jordan type
Hall, J I; Rehren, F; Shpectorov, S.
2014-01-01
An axial algebra over the field $\\mathbb F$ is a commutative algebra generated by idempotents whose adjoint action has multiplicity-free minimal polynomial. For semisimple associative algebras this leads to sums of copies of $\\mathbb F$. Here we consider the first nonassociative case, where adjoint minimal polynomials divide $(x-1)x(x-\\eta)$ for fixed $0\
Energy Technology Data Exchange (ETDEWEB)
Tanaka, K. [Fukui National College of Technology, Fukui (Japan); Kyogoku, K.; Momozono, S.; Nakahara, T. [Tokyo Institute of Technology, Tokyo (Japan)
1999-06-25
In order to investigate lubrication characteristics between rotor and spherical valve plate, a mathematical model of rotor motion has been presented for a piston rod driving type bent-axis-type axial piston pump. The forces and the moments acting on the rotor through the piston rod have been derived from geometric analysis of rotor driving mechanism with the piston rod. An analysis model on mixed lubrication between the rotor and the spherical valve plate has been shown using Average-Flow-Model by Patir-Cheng and the contact theory by Greenwood-Tripp, respectively. In addition, bearing part between the rotor and shaft, supporting element of the rotor, has been regarded as squeeze film bearing. The simulation for the lubrication characteristics, such as minimum film thickness, its occurring position and friction loss between the rotor and the spherical valve plate, will be demonstrated in the paper, part 2. (author)
Spontaneous motion of an elliptic camphor particle
Kitahata, Hiroyuki; Iida, Keita; Nagayama, Masaharu
2013-01-01
The coupling between deformation and motion in a self-propelled system has attracted broader interest. In the present study, we consider an elliptic camphor particle for investigating the effect of particle shape on spontaneous motion. It is concluded that the symmetric spatial distribution of camphor molecules at the water surface becomes unstable first in the direction of a short axis, which induces the camphor disk motion in this direction. Experimental results also support the theoretical analysis. From the present results, we suggest that when an elliptic particle supplies surface-active molecules to the water surface, the particle can exhibit translational motion only in the short-axis direction.
Canonical active Brownian motion
Gluck, Alexander; Huffel, Helmuth; Ilijic, Sasa
2008-01-01
Active Brownian motion is the complex motion of active Brownian particles. They are active in the sense that they can transform their internal energy into energy of motion and thus create complex motion patterns. Theories of active Brownian motion so far imposed couplings between the internal energy and the kinetic energy of the system. We investigate how this idea can be naturally taken further to include also couplings to the potential energy, which finally leads to a general theory of cano...
Influence of axial self-magnetic field component on arcing behavior of spiral-shaped contacts
International Nuclear Information System (INIS)
The transverse magnetic field (TMF) contact design is commonly used in vacuum interrupters. When arcing occurs between the TMF contacts, the contact structure can create a self-induced magnetic field that drives the arc to move and rotate on the contact, and thus local overheating and severe erosion can be avoided. However, TMF contacts could also create an axial self-magnetic component, and the influence of this component on the arc behavior has not been considered to date. In this paper, five different types of Cu-Cr spiral-shaped TMF contacts with three different structures are investigated in a demountable vacuum chamber that contains a high-speed charge-coupled device video camera. It was found that the contact structure greatly influenced the arc behavior, especially in terms of arc rotation and the effective contact area, while contacts with the same slot structure but different diameters showed similar arc behavior and arc motion. The magnetic field distribution and the Lorentz force of each of the three different contact structures are simulated, and the axial self-magnetic field was first taken into consideration for investigation of the TMF contact design. It was found that contact designs that have higher axial self-magnetic field components tend to have arc columns with larger diameters and show poorer arc motion and rotation performance in the experiments
Influence of axial self-magnetic field component on arcing behavior of spiral-shaped contacts
Energy Technology Data Exchange (ETDEWEB)
Feng, Dingyu; Xiu, Shixin, E-mail: xsx@mail.xjtu.edu.cn; Wang, Yi; Liu, Gang [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Yali; Bi, Dongli [Shaanxi Baoguang Vacuum Electric Device Co., Ltd., 53 Xibao Road, Baoji 721006 (China)
2015-10-15
The transverse magnetic field (TMF) contact design is commonly used in vacuum interrupters. When arcing occurs between the TMF contacts, the contact structure can create a self-induced magnetic field that drives the arc to move and rotate on the contact, and thus local overheating and severe erosion can be avoided. However, TMF contacts could also create an axial self-magnetic component, and the influence of this component on the arc behavior has not been considered to date. In this paper, five different types of Cu-Cr spiral-shaped TMF contacts with three different structures are investigated in a demountable vacuum chamber that contains a high-speed charge-coupled device video camera. It was found that the contact structure greatly influenced the arc behavior, especially in terms of arc rotation and the effective contact area, while contacts with the same slot structure but different diameters showed similar arc behavior and arc motion. The magnetic field distribution and the Lorentz force of each of the three different contact structures are simulated, and the axial self-magnetic field was first taken into consideration for investigation of the TMF contact design. It was found that contact designs that have higher axial self-magnetic field components tend to have arc columns with larger diameters and show poorer arc motion and rotation performance in the experiments.
Turbine nozzle/nozzle support structure
Boyd, Gary L.; Shaffer, James E.
1997-01-01
An axial flow turbine's nozzle/nozzle support structure having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse.
Observation of a New Narrow Axial-Vector Meson alpha(1)(1420)
Czech Academy of Sciences Publication Activity Database
Adolph, C.; Akhunzyanov, R.; Alexeev, M.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bisplinghoff, J.; Bodlák, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Burtin, E.; Chang, W.-C.; Chiosso, M.; Choi, I.; Chung, S. U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Dhara, L.; Donskov, S. V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse-Perdekapm, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F. H.; Herrmann, E.; Hinterberger, F.; Horikawa, N.; d´Hose, N.; Hsieh, C.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jarý, V.; Jörg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.; Marchand, C.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neyret, D.; Nikolaenko, V. I.; Nový, J.; Nowak, W. D.; Nunes, A.S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rocco, E.; Rossiyskaya, N. S.; Ryabchikov, D.; Rychter, A.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sbrizzai, G.; Schiavon, P.; Schmeing, S.; Schmidt, K.; Schlüter, T.; Selyunin, A.; Schmieden, H.; Schönning, K.; Schopferer, S.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sozzi, F.; Srnka, Aleš; Stolarski, M.; Šulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Wallner, S.; Weisrock, T.; Wilfert, M.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.
2015-01-01
Roč. 115, č. 8 (2015), 082001:1-6. ISSN 0031-9007 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : COMPASS * pion-nucleon scattering * hadron spectroscopy * light-meson spectrum * axial-vector mesons * exotic mesons Subject RIV: BH - Optics, Masers, Lasers Impact factor: 7.512, year: 2014
The amplitude of fluid-induced vibration of cylinders in axial flow
International Nuclear Information System (INIS)
This report describes a new empirical expression of the amplitude of transverse vibration of cylindrical beams and clusters of cylinders in axial flow, for application to reactor fuel. The expression is based on reported experimental observations covering a variety of geometries, cylinder materials and types of support in water, superheated steam and two-phase mixture flows. (author)
Comparison of Design Methods for Axially Loaded Driven Piles in Cohesionless Soil
DEFF Research Database (Denmark)
Thomassen, Kristina; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo
For offshore wind turbines on deeper waters, a jacket sub-structure supported by axially loaded piles is thought to be the most suitable solution. The design method recommended by API and two CPT-based design methods are compared for two uniform sand profiles. The analysis show great difference in...
Permeability changes of coal cores and briquettes under tri-axial stress conditions
Czech Academy of Sciences Publication Activity Database
Wierzbicki, M.; Konečný, Pavel; Kožušníková, Alena
2014-01-01
Roč. 59, č. 4 (2014), s. 1129-1138. ISSN 0860-7001 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : coal * gas permeability * tri-axial stress * coal briquettes Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 0.608, year: 2013 http://mining.archives.pl
Axial flow positive displacement worm compressor
Murrow, Kurt David (Inventor); Giffin, Rollin George (Inventor); Fakunle, Oladapo (Inventor)
2010-01-01
An axial flow positive displacement compressor has an inlet axially spaced apart and upstream from an outlet. Inner and outer bodies have offset inner and outer axes extend from the inlet to the outlet through first and second sections of a compressor assembly in serial downstream flow relationship. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes respectively. The inner and outer helical blades extend radially outwardly and inwardly respectively. The helical blades have first and second twist slopes in the first and second sections respectively. The first twist slopes are less than the second twist slopes. An engine including the compressor has in downstream serial flow relationship from the compressor a combustor and a high pressure turbine drivingly connected to the compressor by a high pressure shaft.
Proto-I axial-focusing experiments
International Nuclear Information System (INIS)
The time-integrated axial (z) focus of the 4.5-cm-radius Proto I (1.5 MV, 500 kA) radial proton diode is presently limited to approx. 3 mm FWHM. This result is obtained with current neutralized beam transport in a gas cell with 6 Torr argon. If the vertical local divergence were the same (10 or less) as the horizontal divergence, the local divergence alone would produce a 1.5 mm FWHM focus. The axial focal size is evidently limited by time-dependent effects. These are studied by observing the beam incident upon various targets with two time-resolved pinhole cameras. The first camera observes Rutherford-scattered protons from gold targets with an array of 11 siicon PIN detectors. The second camera observes K/sub α/-fluorescence from aluminum targets with 4 independently-gated microchannel plates imaging tubes
Microwave axial dielectric properties of carbon fiber
Hong, Wen; Xiao, Peng; Luo, Heng; Li, Zhuan
2015-10-01
Randomly distributed carbon fibers (CFs) reinforced epoxy resin composites are prepared by the pouring method, the dielectric properties of CF composites with different fiber content and length have been performed in the frequency range from 8.2 to 12.4 GHz. The complex permittivity of the composite increases with the fiber length, which is attributed to the decrease of depolarization field, and increases with the volume fraction, which is attributed to the increase of polarization. A formula, based on the theory of Reynolds-Hugh, is proposed to calculate the effective permittivity of CF composites, and validated by the experiments. The proposed formula is further applied to derive the axial permittivity of CF and analyze the effect of fiber length on the axial permittivity.
Direct optical nanoscopy with axially localized detection
Bourg, N; Dupuis, G; Barroca, T; Bon, P; Lécart, S; Fort, E; Lévêque-Fort, S
2014-01-01
Evanescent light excitation is widely used in super-resolution fluorescence microscopy to confine light and reduce background noise. Herein we propose a method of exploiting evanescent light in the context of emission. When a fluorophore is located in close proximity to a medium with a higher refractive index, its near-field component is converted into light that propagates beyond the critical angle. This so-called Supercritical Angle Fluorescence (SAF) can be captured using a hig-NA objective and used to determine the axial position of the fluorophore with nanometer precision. We introduce a new technique for 3D nanoscopy that combines direct STochastic Optical Reconstruction Microscopy (dSTORM) imaging with dedicated detection of SAF emission. We demonstrate that our approach of a Direct Optical Nanoscopy with Axially Localized Detection (DONALD) yields a typical isotropic 3D localization precision of 20 nm.
Review of Axial Burnup Distribution Considerations for Burnup Credit Calculations
International Nuclear Information System (INIS)
This report attempts to summarize and consolidate the existing knowledge on axial burnup distribution issues that are important to burnup credit criticality safety calculations. Recently released Nuclear Regulatory Commission (NRC) staff guidance permits limited burnup credit, and thus, has prompted resolution of the axial burnup distribution issue. The reactivity difference between the neutron multiplication factor (keff) calculated with explicit representation of the axial burnup distribution and keff calculated assuming a uniform axial burnup is referred to as the ''end effect.'' This end effect is shown to be dependent on many factors, including the axial-burnup profile, total accumulated burnup, cooling time, initial enrichment, assembly design, and the isotopics considered (i.e., actinide-only or actinides plus fission products). Axial modeling studies, efforts related to the development of axial-profile databases, and the determination of bounding axial profiles are also discussed. Finally, areas that could benefit from further efforts are identified
Review of Axial Burnup Distribution Considerations for Burnup Credit Calculations
Energy Technology Data Exchange (ETDEWEB)
Wagner, J.C.; DeHart, M.D.
2000-03-01
This report attempts to summarize and consolidate the existing knowledge on axial burnup distribution issues that are important to burnup credit criticality safety calculations. Recently released Nuclear Regulatory Commission (NRC) staff guidance permits limited burnup credit, and thus, has prompted resolution of the axial burnup distribution issue. The reactivity difference between the neutron multiplication factor (keff) calculated with explicit representation of the axial burnup distribution and keff calculated assuming a uniform axial burnup is referred to as the ``end effect.'' This end effect is shown to be dependent on many factors, including the axial-burnup profile, total accumulated burnup, cooling time, initial enrichment, assembly design, and the isotopics considered (i.e., actinide-only or actinides plus fission products). Axial modeling studies, efforts related to the development of axial-profile databases, and the determination of bounding axial profiles are also discussed. Finally, areas that could benefit from further efforts are identified.
On the problem of axial anomaly in supersymmetric gauge theories
International Nuclear Information System (INIS)
The explicit relation is found between the axial current obeying the Adler-Bardeen theorem and the supersymmetric one belonging to a supermultiplet. It is shown that the axial and superconformal anomalies are consistent in all orders of perturbation theory
Multimode interaction in axially excited cylindrical shells
Silva F. M. A.; Rodrigues L.; Gonçalves P. B.; Del Prado Z. J. G. N
2014-01-01
Cylindrical shells exhibit a dense frequency spectrum, especially near the lowest frequency range. In addition, due to the circumferential symmetry, frequencies occur in pairs. So, in the vicinity of the lowest natural frequencies, several equal or nearly equal frequencies may occur, leading to a complex dynamic behavior. So, the aim of the present work is to investigate the dynamic behavior and stability of cylindrical shells under axial forcing with multiple equal or nearly equal natural fr...
Axial flux permanent magnet brushless machines
Gieras, Jacek F; Kamper, Maarten J
2008-01-01
Axial Flux Permanent Magnet (AFPM) brushless machines are modern electrical machines with a lot of advantages over their conventional counterparts. They are being increasingly used in consumer electronics, public life, instrumentation and automation system, clinical engineering, industrial electromechanical drives, automobile manufacturing industry, electric and hybrid electric vehicles, marine vessels and toys. They are also used in more electric aircrafts and many other applications on larger scale. New applications have also emerged in distributed generation systems (wind turbine generators
Axial Flow Characteristics within a Screw Compressor
Nouri, J. M.; Guerrato, D.; Stosic, N.; Arcoumanis, C.
2008-01-01
Angle-resolved axial mean flow and turbulence characteristics were measured inside the working chamber of the male rotor of a screw compressor with high spatial and temporal resolution using laser Doppler velocimetry at two rotor speeds, 750 and 1000 rpm. Measurements were performed through a transparent window near the discharge port to allow the application of various laser techniques. The results showed that an angular resolution up to 2° could fully describe the flow variation inside the ...
Axial force measurement for esophageal function testing
Gravesen, Flemming H; Funch-Jensen, Peter; Gregersen, Hans; Drewes, Asbjørn Mohr
2009-01-01
The esophagus serves to transport food and fluid from the pharynx to the stomach. Manometry has been the “golden standard” for the diagnosis of esophageal motility diseases for many decades. Hence, esophageal function is normally evaluated by means of manometry even though it reflects the squeeze force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure o...
Axially evoked postural reflexes: influence of task
Govender, Sendhil; Dennis, Danielle L.; Colebatch, James G.
2014-01-01
Postural reflexes were recorded in healthy subjects (n = 17) using brief axial accelerations and tap stimuli applied at the vertebra prominens (C7) and manubrium sterni. Short latency (SL) responses were recorded from the soleus, hamstrings and tibialis anterior muscles and expressed as a percentage of the background EMG prior to stimulus onset. In the majority of postural conditions tested, subjects were recorded standing erect and leaning forward with their feet together. The SL response wa...
Numerical simulation of an axial blood pump.
Chua, Leok Poh; Su, Boyang; Lim, Tau Meng; Zhou, Tongming
2007-07-01
The axial blood pump with a magnetically suspended impeller is superior to other artificial blood pumps because of its small size. In this article, the distributions of velocity, path line, pressure, and shear stress in the straightener, the rotor, and the diffuser of the axial blood pump, as well as the gap zone were obtained using the commercial software, Fluent (version 6.2). The main focus was on the flow field of the blood pump. The numerical results showed that the axial blood pump could produce 5.14 L/min of blood at 100 mm Hg through the outlet when rotating at 11,000 rpm. However, there was a leakage flow of 1.06 L/min in the gap between the rotor cylinder and the pump housing, and thus the overall flow rate the impeller could generate was 6.2 L/min. The numerical results showed that 75% of the scalar shear stresses (SSs) were less than 250 Pa, and 10% were higher than 500 Pa within the whole pump. The high SS region appeared around the blade tip where a large variation of velocity direction and magnitude was found, which might be due to the steep angle variation at the blade tip. Because the exposure time of the blood cell at the high SS region within the pump was relatively short, it might not cause serious damage to the blood cells, but the improvement of blade profile should be considered in the future design of the axial pump. PMID:17584481
The window of opportunity: a relevant concept for axial spondyloarthritis
Robinson, Philip C.; Brown, Matthew A.
2014-01-01
The window of opportunity is a concept critical to rheumatoid arthritis treatment. Early treatment changes the outcome of rheumatoid arthritis treatment, in that response rates are higher with earlier disease-modifying anti-rheumatic drug treatment and damage is substantially reduced. Axial spondyloarthritis is an inflammatory axial disease encompassing both nonradiographic axial spondyloarthritis and established ankylosing spondylitis. In axial spondyloarthritis, studies of magnetic resonanc...
Extra-Axial Medulloblastoma in the Cerebellar Hemisphere
Chung, Eui Jin; Jeun, Sin Soo
2014-01-01
Extra-axial medulloblastoma is a rare phenomenon. We report a case in a 5-year-old boy who presented with nausea, vomiting, and gait disturbance. He was treated with total removal of the tumor. This is the first case of an extra-axially located medulloblastoma occurring in the cerebellar hemisphere posteriolateral to the cerebellopontine angle in Korea. Although the extra-axial occurrence of medulloblastoma is rare, it should be considered in the differential diagnosis of extra-axial lesions ...
FREE NON-LINEAR VIBRATION OF AXIALLY MOVING BEAMS WITH FIXED ENDS
Institute of Scientific and Technical Information of China (English)
Yang Xiaodong; Chen Liqun
2005-01-01
The free non-linear vibration of axially moving, elastic, and tensioned beams on fixed supports is investigated in this paper. Two types of non-linearity, namely, the differential type and integro-differential type, are analyzed. Approximate solutions are sought using the method of multiple scales. The contribution of non-linearity to the response increases with the axial speed,and grows most rapidly near the critical speed. It has been found that the differential type nonlinearity is stronger than the integro-differential type non-linearity by analyzing the non-linear effects on natural frequencies.
A New Technique for Analysis of Static Eccentricity in Axial Flux Resolver
Tootoonchian, F.; Abbaszadeh, K.; Ardebili, M.
2012-01-01
Resolvers have been widely used in motion control systems as position sensors. This paper deals with the analysis of Axial Flux Resolvers. Axial flux resolvers are a group of resolvers which can be used in high performance servomechanisms. The accuracy of resolver detected position is affected by errors. Some of these errors are caused by speed fluctuations, permeance ripples, unbalanced voltages, and eccentricity between rotor and stator. Among these errors the static eccentricity > and Lq values and then, the static eccentricity effect based on the developed model is studied. A novel algorithm is proposed for suppressing the eccentricity error. This method is based on analytical model and modern control fundamentals. In a comparison, simulation and experimental results show good agreement. Finally, the effect of air gap length, pole number and excitation voltage on position error of eccentric AFR is investigated, practically.
Bending vibration of axially loaded Timoshenko beams with locally distributed Kelvin-Voigt damping
Chen, Wei-Ren
2011-06-01
Utilizing the Timoshenko beam theory and applying Hamilton's principle, the bending vibration equations of an axially loaded beam with locally distributed internal damping of the Kelvin-Voigt type are established. The partial differential equations of motion are then discretized into linear second-order ordinary differential equations based on a finite element method. A quadratic eigenvalue problem of a damped system is formed to determine the eigenfrequencies of the damped beams. The effects of the internal damping, sizes and locations of damped segment, axial load and restraint types on the damping and oscillating parts of the damped natural frequency are investigated. It is believed that the present study is valuable for better understanding the influence of various parameters of the damped beam on its vibration characteristics.
Dynamics of Axial Symmetric System in Self-Interacting Brans-Dicke Gravity
Sharif, M
2016-01-01
This paper investigates dynamics of axial reflection symmetric model in self-interacting Brans-Dicke gravity for anisotropic fluid. We formulate hydrodynamical equations and discuss oscillations using time-dependent perturbation for both spin as well as spin-independent cases. The expressions of frequency, total energy density and equation of motion of oscillating model are obtained. We study instability of oscillating models in weak approximations. It is found that the oscillations and stability of the model depend upon the dark energy source along with anisotropy and reflection effects. We conclude that the axial reflection system remains stable for stiffness parameter $\\Gamma=1$, collapses for $\\Gamma>1$ and becomes unstable for $0<\\Gamma<1$.
Vibrational power flow of a finite cylindrical shell with discrete axial stiffeners
Institute of Scientific and Technical Information of China (English)
LIU Yanmei; HUANG Xieqing
2002-01-01
The structural wave power flows in an elastic finite cylindrical shell with discrete axial stiffeners are studied when a simple harmonic force is applied on it. The equations of motion of the shell are derived by using Flugge equation and Hamilton variational principle,and the responses of the shell are obtained. By use of the basic definition of the power flow, the characteristics of axial propagation of the power flow supplied by input structure and carried by different shell internal forces of a forced shell are investigated. The effects of parameters, such as relative location of driving force and stringer, driving force type and structural damping on the vibrational power flows in the shell, are discussed. These provide some theoretical bases for vibration control and noise reduction of this kind of structure.
Resolution of axial anomaly problem in supersymmetric gauge theories
International Nuclear Information System (INIS)
The explicit form of transformation is found which converters the operators, involved in axial anomaly, from the renormalization scheme obeying the Adler-BaAdeen theorem to a supersymmetric one. It is shown that there is no contradiction between axial current and superconformal anomalies. In supersymmetric scheme the axial current and its anomaly belong to the corresponding supermultiplets
Directory of Open Access Journals (Sweden)
Frederico Martins Alves da Silva
2015-01-01
Full Text Available This work investigates the influence of Young’s modulus, shells thickness, and geometrical imperfection uncertainties on the parametric instability loads of simply supported axially excited cylindrical shells. The Donnell nonlinear shallow shell theory is used for the displacement field of the cylindrical shell and the parameters under investigation are considered as uncertain parameters with a known probability density function in the equilibrium equation. The uncertainties are discretized as Hermite-Chaos polynomials together with the Galerkin stochastic procedure that discretizes the stochastic equation in a set of deterministic equations of motion. Then, a general expression for the transversal displacement is obtained by a perturbation procedure which identifies all nonlinear modes that couple with the linear modes. So, a particular solution is selected which ensures the convergence of the response up to very large deflections. Applying the standard Galerkin method, a discrete system in time domain that considers the uncertainties is obtained and solved by fourth-order Runge-Kutta method. Several numerical strategies are used to study the nonlinear behavior of the shell considering the uncertainties in the parameters. Special attention is given to the influence of the uncertainties on the parametric instability and time response, showing that the Hermite-Chaos polynomial is a good numerical tool.
A new strategy of axial power distribution control based on three axial offsets concept
International Nuclear Information System (INIS)
We have proposed a very simple control procedure for axial xenon oscillation control based on a characteristic trajectory. The trajectory is drawn by three offsets of power distributions, namely, AOp, AOi and AOx. They are defined as the offset of axial power distribution, the offset of the power distribution under which the current iodine distribution is obtained as the equilibrium and that for xenon distribution, respectively. When these offsets are plotted on X-Y plane for (AOp-AOx, AOi-AOx) the trajectory draws a quite characteristic ellipse (or an elliptic spiral). On the other hands, Constant Axial Offset Control (CAOC) procedure is adopted as axial power distribution control strategy during both base load and load following operations in domestic PWRs. In the previous paper, we have presented an innovative procedure of axial power distribution control during load following in PWRs based on this trajectory such that the AOp-AOx is to be controlled to zero when the value deviates the pre-determined limiting values. In this paper we propose a modified control strategy to get more stability of axial power distributions. In this strategy, we control the trajectory to be close to the major axis of the ellipse when the power distribution reaches the limiting values. In other words, the plot is not controlled only to reduce AOp-AOx but also AOi-AOx is taken into account at the same time. It is known that when the plot is controlled to the major axis, it means that the point gives the peak position of axial xenon oscillation. Therefore xenon oscillation will not increase its amplitude any more. Thus more stable axial power distribution control is attained. This kind of design concept is quite important especially for the future PWRs with elongated fuel length and longer core life. Because in a longer effective core and also the longer core life, it has been known that the stability of axial xenon oscillation becomes more unstable. In this paper, some simulation
Motion motif extraction from high-dimensional motion information
Araki, Yutaka; Arita, Daisaku; Taniguchi, Rin-ichiro
2006-01-01
Recently, there are a lot of researches on virtual environments for distant human communication. Real-time Human Proxy (RHP), which is a concept for such a virtual environment, has been proposed. For realizing natural communication by RHP, it is necessary to recognize human actions essential for human communication. However, it is difficult for system developers to decide which human actions should be recognized. For supporting the decision, we propose a human motion analysis method which aut...
NUMERICAL PREDICTION OF COMPOSITE BEAM SUBJECTED TO COMBINED NEGATIVE BENDING AND AXIAL TENSION
Directory of Open Access Journals (Sweden)
MAHESAN BAVAN
2013-08-01
Full Text Available The present study has investigated the finite element method (FEM techniques of composite beam subjected to combined axial tension and negative bending. The negative bending regions of composite beams are influenced by worsen failures due to various levels of axial tensile loads on steel section especially in the regions near internal supports. Three dimensional solid FEM model was developed to accurately predict the unfavourable phenomenon of cracking of concrete and compression of steel in the negative bending regions of composite beam due to axial tensile loads. The prediction of quasi-static solution was extensively analysed with various deformation speeds and energy stabilities. The FEM model was then validated with existing experimental data. Reasonable agreements were observed between the results of FEM model and experimental analysis in the combination of vertical-axial forces and failure modes on ultimate limit state behaviour. The local failure modes known as shear studs failure, excess yielding on steel beam and crushing on concrete were completely verified by extensive similarity between the numerical and experimental results. Finally, a proper way of modelling techniques for large FEM models by considering uncertainties of material behaviour due to biaxial loadings and complex contact interactions is discussed. Further, the model is suggested for the limit state prediction of composite beam with calibrating necessary degree of the combined axial loads.
Internal resonance of axially moving laminated circular cylindrical shells
Wang, Yan Qing; Liang, Li; Guo, Xing Hui
2013-11-01
The nonlinear vibrations of a thin, elastic, laminated composite circular cylindrical shell, moving in axial direction and having an internal resonance, are investigated in this study. Nonlinearities due to large-amplitude shell motion are considered by using Donnell's nonlinear shallow-shell theory, with consideration of the effect of viscous structure damping. Differently from conventional Donnell's nonlinear shallow-shell equations, an improved nonlinear model without employing Airy stress function is developed to study the nonlinear dynamics of thin shells. The system is discretized by Galerkin's method while a model involving four degrees of freedom, allowing for the traveling wave response of the shell, is adopted. The method of harmonic balance is applied to study the nonlinear dynamic responses of the multi-degrees-of-freedom system. When the structure is excited close to a resonant frequency, very intricate frequency-response curves are obtained, which show strong modal interactions and one-to-one-to-one-to-one internal resonance phenomenon. The effects of different parameters on the complex dynamic response are investigated in this study. The stability of steady-state solutions is also analyzed in detail.
Neutron Star Asteroseismology. Axial Crust Oscillations in the Cowling Approximation
Samuelsson, L; Samuelsson, Lars; Andersson, Nils
2006-01-01
Recent observations of quasi-periodic oscillations in the aftermath of giant flares in soft gamma-ray repeaters suggest a close coupling between the seismic motion of the crust after a major quake and the modes of oscillations in a magnetar. In this paper we consider the purely elastic modes of oscillation in the crust of a neutron star in the relativistic Cowling approximation (disregarding any magnetic field). We determine the axial crust modes for a large set of stellar models, using a state-of-the-art crust equation of state and a wide range of core masses and radii. We also devise useful approximate formulae for the mode-frequencies. We show that the relative crust thickness is well described by a function of the compactness of the star and a parameter describing the compressibility of the crust only. Considering the observational data for SGR 1900+14 and SGR 1806-20, we demonstrate how our results can be used to constrain the mass and radius of an oscillating neutron star.
Ottaviano, Giuseppe; Kohli, Pushmeet
2013-01-01
Traditional video compression methods obtain a compact representation for image frames by computing coarse motion fields defined on patches of pixels called blocks, in order to compensate for the motion in the scene across frames. This piecewise constant approximation makes the motion field efficiently encodable, but it introduces block artifacts in the warped image frame. In this paper, we address the problem of estimating dense motion fields that, while accurately predicting one frame from ...
Axially-symmetric Neutron stars: Implication of rapid rotation
Sharma, B K
2009-01-01
Models of relativistic rotating neutron star composed of hyperon rich matter is constructed in the framework of an effective field theory in the mean-field approach. The gross properties of compact star is calculated at both static and the mass-shedding limit in the axially symmetric basis. The effect of appearance and abundance of hyperons on equation of state of dense matter and stellar properties is lineated with particular emphasis on the underlying nuclear interactions. We find that the models can explain fast rotations, which supports the existence of millisecond pulsars. An important offshoot of the present investigation is that, irrespective of the model parameters and interaction taken, the star seems to sustain faster rotations (an increase in rotational frequency up to $\\approx$ 50%) without any further deformation.
Axial flow heat exchanger devices and methods for heat transfer using axial flow devices
Koplow, Jeffrey P.
2016-02-16
Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferred across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.
CFD Simulation of Casing Treatment of Axial Flow Compressors
DeWitt, Kenneth
2005-01-01
A computational study is carried out to understand the physical mechanism responsible for the improvement in stall margin of an axial flow rotor due to the circumferential casing grooves. It is shown that the computational tool used predicts an increase in operating range of the rotor when casing grooves are present. A budget of the axial momentum equation is carried out at the rotor casing in the tip gap in order to uncover the physical process behind this stall margin improvement. It is shown that for the smooth casing the net axial pressure force . However in the presence of casing grooves the net axial shear stress force acting at the casing is augmented by the axial force due to the radial transport of axial momentum, which occurs across the grooves and power stream interface. This additional force adds to the net axial viscous sheer force and thus leads to an increase in the stall margin of the rotor.
A free-breathing lung motion model
Zhao, Tianyu
Lung cancer has been the leading cause of cancer deaths for decades in the United States. Although radiotherapy is one of the most effective treatments, side effects from error in delivery of radiation due to organ motion during breathing remain a significant issue. To compensate the breathing motion during the treatment, a free breathing lung motion model, x= x0+αv+betaf, was developed and discussed, where x is the position of a piece of tissue located at reference position x0. α is a parameter which characterizes the motion due to local air filling (motion as a function of tidal volume) and beta is the parameter that accounts for the motion due to the imbalance of dynamical stress distributions during inspiration and exhalation which cause lung motion hysteresis (motion as a function of airflow). The parameters α and beta together provide a quantitative characterization of breathing motion that inherently includes the complex hysteresis interplay. The theoretical foundation of the model was built by investigating the stress distribution inside of a lung and the biomechanical properties of the lung tissues. Accuracy of the model was investigated by using 49 free-breathing patient data sets. Applications of the model in localizing lung cancer, monitoring radiation damage and suppressing artifacts in free-breathing PET images were also discussed. This work supported in part by NIHR01CA096679 and NIHR01CA116712.
Plasma flow crisis and limiting electron temperature in a vacuum arc and in axial magnetic field
International Nuclear Information System (INIS)
One studied possibility of supersonic motion of cathode plasma in a weak-current vacuum arc placed in axial magnetic field. Increase of electron temperature is shown to result inevitably in reduction of plasma speed up to sonic speed, that is, flow crisis. One derived dependence of the boundary length of plasma stationary flow on magnetic field. The maximum attainable electron temperature of plasma was determined to be governed by ion initial energy and to be equal to the triple value of electron temperature within cathode spot range
Drop size selection in axially heated co-axial fiber capillary instability
Mowlavi, Saviz; Brun, Pierre-Thomas; Gallaire, Francois
2015-11-01
We analyze the sphere size selection mechanism in silicon-in-silica sphere formation through the application of an external axial thermal gradient to a co-axial silicon-in-silica fiber (Gumennik et al., Nature Com., 2013). We first apply a convective/absolute stability analysis to the in-fibre capillary instability governing the sphere formation and demonstrate that the resulting wavelength selection predicts a finite but still too large wavelength. A global stability analysis is then pursued, which accounts for the spatial inhomogeneity of the base flow. F.G. acknowledges funding from ERC SimCoMiCs 280117.
Axial electron-channelling analysis of perovskite
International Nuclear Information System (INIS)
The orientation dependence of characteristic X-ray emission (the Borrmann effect) under near-zone-axis diffraction conditions has been used to identify the site preferences of strontium, zirconium and uranium impurities within a CaTiO3 (perovskite) host structure. As characteristic emission lines from these impurities occur at both higher and lower energies than the calcium or titanium K-shell excitations, effects of delocalization are clearly measureable, and are used as a tool in axial electron channeling or ALCHEMI analysis. It is found that strontium and uranium strongly partition into calcium sites, whereas zirconium occupies titanium sites. (author)
Single Band Helical Antenna in Axial Mode
Directory of Open Access Journals (Sweden)
Parminder Singh
2012-11-01
Full Text Available Helical antennas have been widely used in a various useful applications, due to their low weight and low profile conformability, easy and cheap realization.Radiation properties of this antenna are examined both theoretically and experimentally. In this paper, an attempt has been made to investigate new helical antenna structure for Applications. CST MWS Software is used for the simulation and design calculations of the helical antennas. The axial ratio, return loss, VSWR, Directivity, gain, radiation pattern is evaluated. Using CST MWS simulation software proposed antenna is designed/simulated and optimized. The antenna exhibits a single band from 0 GHz to 3 GHz for GPS and several satellite applications