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Sample records for stable axial deformation

  1. Dynamic control of knee axial deformities

    Directory of Open Access Journals (Sweden)

    E. E. Malyshev

    2013-01-01

    Full Text Available The authors have evaluated the clinical examination of the patients with axial malalignments in the knee by the original method and device which was named varovalgometer. The measurements were conducted by tension of the cord through the spina iliaca anterior superior and the middle of the lower pole of patella. The deviation of the center of the ankle estimated by metal ruler which was positioned perpendicular to the lower leg axis on the level of the ankle joint line. The results of comparison of our method and computer navigation in 53 patients during the TKA show no statistically significant varieties but they differ by average 5° of valgus in clinical examination in comparison with mechanical axis which was identified by computer navigation. The dynamic control of axial malalignment can be used in clinical practice for estimation of the results of treatment of pathology with axial deformities in the knee; for the control of reduction and secondary displacement of the fractures around the knee; for assessment of instability; in planning of correctional osteotomies and intraoperative control of deformity correction; for estimation of Q angle in subluxation and recurrent dislocation of patella; in planning of TKA; during the growth of child it allows to assess the progression of deformity.

  2. Cyclic Axial-Torsional Deformation Behavior of a Cobalt-Base Superalloy

    Science.gov (United States)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1995-01-01

    The cyclic, high-temperature deformation behavior of a wrought cobalt-base super-alloy, Haynes 188, is investigated under combined axial and torsional loads. This is accomplished through the examination of hysteresis loops generated from a biaxial fatigue test program. A high-temperature axial, torsional, and combined axial-torsional fatigue database has been generated on Haynes 188 at 760 C. Cyclic loading tests have been conducted on uniform gage section tubular specimens in a servohydraulic axial-torsional test rig. Test control and data acquisition were accomplished with a minicomputer. The fatigue behavior of Haynes 188 at 760 C under axial, torsional, and combined axial-torsional loads and the monotonic and cyclic deformation behaviors under axial and torsional loads have been previously reported. In this paper, the cyclic hardening characteristics and typical hysteresis loops in the axial stress versus axial strain, shear stress ,versus engineering shear strain, axial strain versus engineering shear strain. and axial stress versus shear stress spaces are presented for cyclic in-phase and out-of-phase axial-torsional tests. For in-phase tests, three different values of the proportionality constant lambda (the ratio of engineering shear strain amplitude to axial strain amplitude, are examined, viz. 0.86, 1.73, and 3.46. In the out-of-phase tests, three different values of the phase angle, phi (between the axial and engineering shear strain waveforms), are studied, viz., 30, 60, and 90 degrees with lambda equals 1.73. The cyclic hardening behaviors of all the tests conducted on Haynes 188 at 760 C are evaluated using the von Mises equivalent stress-strain and the maximum shear stress-maximum engineering shear strain (Tresca) curves. Comparisons are also made between the hardening behaviors of cyclic axial, torsional, and combined in-phase (lambda = 1.73 and phi = 0) and out-of-phase (lambda = 1.73 and phi = 90') axial-torsional fatigue tests. These comparisons

  3. Theoretical study on effect of radial and axial deformation on ...

    Indian Academy of Sciences (India)

    However, localization of the electronic state near the Fermi level is weak in .... ods (32 C atoms and 32 Si atoms), 2 periods (16 C atoms and 16 Si atoms) and 2 periods (16 C atoms and .... tribute to conduction in deformed structures; FMOs are weakly localized that facilitates tunneling. 1·05 distortion are shown in figure 5.

  4. 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.

  5. The stable stiffness triangle - drained sand during deformation cycles

    DEFF Research Database (Denmark)

    Sabaliauskas, Tomas; Ibsen, Lars Bo

    2017-01-01

    Cyclic, drained sand stiffness was observed using the Danish triaxial appa- ratus. New, deformation dependant soil property (the stable stiffness triangle) was detected. Using the the stable stiffness triangle, secant stiffness of drained sand was plausible to predict (and control) even during ir...... findings can find application in off-shore, seismic and other engi- neering practice, or inspire new branches of research and modelling wherever dynamic, cyclic or transient loaded sand is encountered....

  6. Symmetries and supersymmetries of the dirac hamiltonian with axially deformed scalar and vector potentials.

    Science.gov (United States)

    Leviatan, A

    2009-07-24

    We consider several classes of symmetries of the Dirac Hamiltonian in 3 + 1 dimensions, with axially deformed scalar and vector potentials. The symmetries include the known pseudospin and spin limits and additional symmetries which occur when the potentials depend on different variables. Supersymmetries are observed within each class and the corresponding charges are identified.

  7. Symmetries and Supersymmetries of the Dirac Hamiltonian with Axially Deformed Scalar and Vector Potentials

    International Nuclear Information System (INIS)

    Leviatan, A.

    2009-01-01

    We consider several classes of symmetries of the Dirac Hamiltonian in 3+1 dimensions, with axially deformed scalar and vector potentials. The symmetries include the known pseudospin and spin limits and additional symmetries which occur when the potentials depend on different variables. Supersymmetries are observed within each class and the corresponding charges are identified.

  8. Hexadecapolar deformation in non-axial nuclei. Its influence upon coupled channel equations

    International Nuclear Information System (INIS)

    Cabezas Solorzano, R.; Lopez Tuero, J.

    1987-01-01

    A study of the influence of the hexadecapolar deformation in non-axial nuclei upon coupled channel equations is made. An evaluation of reduced matrix elements refer to all possible transitions for the coupled scheme 0 1 + - 2 1 + - 4 1 + 2 2 + - 3 1 + - 4 2 + is calculated. It is also shown that for a correct description of the low-energy neutron inelastic scattering process in transitional nuclei it is necessary to consider non-axial hexadecapolar modes in those nuclei susceptible to it

  9. Superconstructs in the treatment of charcot foot deformity: plantar plating, locked plating, and axial screw fixation.

    Science.gov (United States)

    Sammarco, V James

    2009-09-01

    Management of Charcot's deformity of the foot and ankle continues to challenge physicians. Medical co-morbidity, peripheral neuropathy, vascular disease, and immune impairment cause severe problems for these patients and, when combined with neuroarthropathy, can lead to amputation. Progressive bony deformity and bone resorption, which may accompany neuroarthropathy, only increase the challenge of surgical treatment. These challenges have led physicians to develop "superconstruct" techniques to improve fixation, whereby fusion is extended beyond the zone of injury to include joints that are not affected, bone resection is performed to shorten the extremity to allow for adequate reduction of deformity without undue tension on the soft tissue envelope, the strongest device is used that can be tolerated by the soft tissue envelope; and the devices are applied in a novel position that maximizes mechanical function. This article reviews three techniques designed to achieve lasting deformity correction and successful arthrodesis: plantar plating, locked plating, and axial screw fixation.

  10. Studies of Stable Octupole Deformations in the Radium Region

    CERN Multimedia

    2002-01-01

    The purpose of the present project is to locate and identify states in the atomic nuclei possessing stable pearshaped octupole deformation. Such states, formally related to the structures known in molecular physics, manifest themselves as families of parity doublets in odd nuclei.\\\\ \\\\ The best possibilities for observing stable octupole deformations are offered in the Ra-region. Both theoretical calculations and experimental indications support such expectations. Such indications are the non-observation of two-phonon octupole vibrational states in the ISOLDE studies of the even-even radium nuclei, and the reversed sign of the decoupling factor of the ground state band in |2|2|5Ra observed in the single-neutron transfer reactions. In order to establish the predicted strong E1 and E3-transitions between the parity doublets in odd nuclei with stable octupole deformations it is proposed to study conversion electrons in odd-mass francium radium and radon isotopes following the @b-decay of francium and astatine. \\...

  11. Microscopic Measurements of Axial Accumulation of Red Blood Cells in Capillary Flows Effects of Deformability

    Science.gov (United States)

    Sasaki, Takahiro; Seki, Junji; Itano, Tomoaki; Sugihara-Seki, Masako

    2017-11-01

    In the microcirculation, red blood cells (RBCs) are known to accumulate in the region near the central axis of microvessels, which is called the ``axial accumulation''. Although this behavior of RBCs is considered to originate from high deformability of RBCs, there have been few experimental studies on the mechanism. In order to elucidate the effect of RBC deformability on the axial accumulation, we measured the cross-sectional distributions of RBCs flowing through capillary tubes with a high spatial resolution by a newly devised observation system for intact and softened RBCs as well as hardened RBCs to various degrees. It was found that the intact and softened RBCs are concentrated in the small area centered on the tube axis, whereas the hardened RBCs are dispersed widely over the tube cross section dependent on the degree of hardness. These results demonstrate clearly the essential role of the deformability of RBCs in the ``axial accumulation'' of RBCs. JSPS KAKENHI Grant Number 17H03176, Kansai University ORDIST group funds.

  12. Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

    Science.gov (United States)

    Carstensen, J.; Stoller, P.; Galletti, B.; Doiron, C. B.; Sokolov, A.

    2017-08-01

    Two-color spatial carrier wave interferometry employing pulsed 532- and 671-nm lasers is used to measure the electron-density and heavy-particle-density profiles in the stagnation point of a stable, axially blown arc in argon for currents of 50 to 200 A and stagnation point pressures of 0.2 to 16 bar. This technique takes advantage of the fact that the free-electron contribution to the refractive index depends strongly on the wavelength, while that of the heavy particles does not. The high spatial resolution achieved allows the hot core of the arc to be readily distinguished from the surrounding boundary layer. A custom-built test device is used to ensure flow conditions that lead to a stable, axisymmetric arc; this permits the reconstruction of the density and temperature profiles using a single projection (interferometric image) of the refractive-index distribution through the arc (at two wavelengths). The arc radius determined from the heavy-particle density decreases with increasing stagnation pressure and increases with the current. These measurements are in good agreement with a simple axially blown arc model taking into account Ohmic heating, radiation losses, and enthalpy flow for core temperatures of approximately 16 500 K. The measured electron density at the center of the arc agrees well with a prediction based on local thermodynamic equilibrium.

  13. Fully automatic measurements of axial vertebral rotation for assessment of spinal deformity in idiopathic scoliosis

    Science.gov (United States)

    Forsberg, Daniel; Lundström, Claes; Andersson, Mats; Vavruch, Ludvig; Tropp, Hans; Knutsson, Hans

    2013-03-01

    Reliable measurements of spinal deformities in idiopathic scoliosis are vital, since they are used for assessing the degree of scoliosis, deciding upon treatment and monitoring the progression of the disease. However, commonly used two dimensional methods (e.g. the Cobb angle) do not fully capture the three dimensional deformity at hand in scoliosis, of which axial vertebral rotation (AVR) is considered to be of great importance. There are manual methods for measuring the AVR, but they are often time-consuming and related with a high intra- and inter-observer variability. In this paper, we present a fully automatic method for estimating the AVR in images from computed tomography. The proposed method is evaluated on four scoliotic patients with 17 vertebrae each and compared with manual measurements performed by three observers using the standard method by Aaro-Dahlborn. The comparison shows that the difference in measured AVR between automatic and manual measurements are on the same level as the inter-observer difference. This is further supported by a high intraclass correlation coefficient (0.971-0.979), obtained when comparing the automatic measurements with the manual measurements of each observer. Hence, the provided results and the computational performance, only requiring approximately 10 to 15 s for processing an entire volume, demonstrate the potential clinical value of the proposed method.

  14. Experimental and numerical investigations of stable crack growth of axial surface flaws in a pressure vessel

    International Nuclear Information System (INIS)

    Brocks, W.; Krafka, H.; Mueller, W.; Wobst, K.

    1988-01-01

    In connection with the problem of the transferability of parameters obtained experimentally with the help of fracture-mechanical test specimens and used for the initiation and the stable propagation of cracks in cases of pulsating stress and of the elasto-plastic behaviour of construction components, a pressure vessel with an inside diameter of 1500 mm, a cylindrical length of 3000 mm and a wall thickness of 40 mm was hydraulically loaded with the help of internal pressure in the first stage, to attain an average crack growth of 1 mm at Δ a ≅, the loading taking place at about 21deg C. This stress-free annealed vessel exhibited an axial semielliptical vibration-induced surface crack about 181 mm long and 20 mm deep, as a test defect, in a welded circular blank made of the steel 20MnMoNi 55. The fractographic analysis of the first stable crack revealed that its growth rate of Δa was highest in the area of transition from the weak to the strong bend of the crack front (55deg m /σ v (average principal stress: σ m , Mises' reference stress: σ v v). A comparison of the experimental with the numerical results from the first stable crack shows that the local stable crack growth Δa cannot be calculated solely with reference to J, because Δa appears to depend essentially on the quotient σ m /σ v . (orig./MM) [de

  15. C sub 6 sub 0 fullerene and its molecular complexes under axial and shear deformation

    CERN Document Server

    Spitsina, N G; Bashkin, I V; Meletov, K P

    2002-01-01

    We have studied the pristine C sub 6 sub 0 and its molecular complexes with the organic donors bis(ethylenedithio) tetrathiafulvalene (BEDT-TTF or ET) and tetramethyltetraselenafulvalene (TMTSF) by means of ESR and Raman spectroscopy at high pressure. The important changes in the ESR signal of C sub 6 sub 0 were observed under axial pressure combined with shear deformation. It is shown that the treatment at a anisotropic pressure of 4 GPa results in a reduction in the symmetry of the C sub 6 sub 0 molecule and the formation of radicals. Treatment of the molecular complex of (ET) sub 2 centre dot C sub 6 sub 0 at a pressure of approx 4.5 GPa and a temperature of 150 deg. C leads to the formation of C sub 6 sub 0 dimers. The Raman spectra of the molecular complex C sub 6 sub 0 centre dot TMTSF centre dot 2(CS sub 2) were measured in situ at ambient temperature and pressures up to 9.5 GPa. The pressure behaviour of the Raman peaks reveals singularity at 5.0 +- 0.5 GPa related to the softening and splitting of so...

  16. Correction of the axial and appendicular deformities in a patient with Silver-Russel syndrome

    Directory of Open Access Journals (Sweden)

    Ali Al Kaissi

    2015-01-01

    Full Text Available Background: Scoliosis and limb length discrepancy are the major orthopaedic abnormalities in patients with Silver-Russel syndrome (SRS. In this paper, we describe a series of orthopaedic interventions in an attempt to overcome the progressive pathologic mechanism in a 7-year-old girl who manifested the full phenotypic features of SRS. Materials and Methods: Unilateral hip dislocation, progressive scoliosis and limb length discrepancy have been dealt with through Pemberton osteotomy, spinal fusion and Taylor-Spatial-Frame respectively. Results: In order to correct the axial and the appendicular deformities a sum of seven operations were performed (between the age of 7 years and 13 years. Pemberton osteotomy was performed to treat dislocation of her right hip because of developmental dysplasia of the hip. Spinal fusion (spondylodesis of segments Th3-L5 was done to correct her scoliosis. And, to overcome the limb length discrepancy of 15-cm we used Taylor-Spatial-Frame with percutaneous distal corticotomy of the femur, and the proximal tibia, as well as the foot, were performed. We were able to minimize the limb length discrepancy to 5 cm. The girl became able to walk with the aid of a below knee orthosis and through lifting the left limb with 5-cm height shoe. Conclusion: Limb lengthening surgery in patients with multiple malformation complex as in SRS is associated with high recurrence risk because of; muscular hypotonia, overtubulation of the long bones, and the poor bone regenerative quality. Our interventions were principally directed towards improving the cosmetic outlook, functions and the biomechanics.

  17. Influence of Lateral Incision on Inhomogeneous Deformation of a Nickel [001] - Single Cristal at Axial Compression

    Science.gov (United States)

    Lychagin, D. V.; Alfyorova, E. A.; Lychagin, M. V.; Dilun, Czyan

    2016-04-01

    We used the scanning electron microscopy and the electron backscattered diffraction to investigate a deformation relief and a crystallographic disorientation of a nickel [001] single crystal with {100} faces with a lateral incision. We identified that the lateral incision can change the shear domains distribution pattern in the sample by creating additional deformation domains near the incision. The change in the patterns of the misorientation accumulation on the mutually perpendicular faces accompanies this deformation. We established that the orientation alteration occurs toward the increase of the Schmid factor for the slip systems in two of the four (previously equally loaded) slip planes. This method of shear deformation contributes to an optimal mutually consistent deformation in the adjacent areas of the single crystal.

  18. Concrete-Filled-Large Deformable FRP Tubular Columns under Axial Compressive Loading

    Directory of Open Access Journals (Sweden)

    Omar I. Abdelkarim

    2015-10-01

    Full Text Available The behavior of concrete-filled fiber tubes (CFFT polymers under axial compressive loading was investigated. Unlike the traditional fiber reinforced polymers (FRP such as carbon, glass, aramid, etc., the FRP tubes in this study were designed using large rupture strains FRP which are made of recycled materials such as plastic bottles; hence, large rupture strain (LRS FRP composites are environmentally friendly and can be used in the context of green construction. This study performed finite element (FE analysis using LS-DYNA software to conduct an extensive parametric study on CFFT. The effects of the FRP confinement ratio, the unconfined concrete compressive strength ( , column size, and column aspect ratio on the behavior of the CFFT under axial compressive loading were investigated during this study. A comparison between the behavior of the CFFTs with LRS-FRP and those with traditional FRP (carbon and glass with a high range of confinement ratios was conducted as well. A new hybrid FRP system combined with traditional and LRS-FRP is proposed. Generally, the CFFTs with LRS-FRP showed remarkable behavior under axial loading in strength and ultimate strain. Equations to estimate the concrete dilation parameter and dilation angle of the CFFTs with LRS-FRP tubes and hybrid FRP tubes are suggested.

  19. Multi-Axial Deformation Setup for Microscopic Testing of Sheet Metal to Fracture

    NARCIS (Netherlands)

    Tasan, C.C.; Hoefnagels, J.P.M.; Dekkers, E.C.A.; Geers, M.G.D.

    2012-01-01

    While the industrial interest in sheet metal with improved specific-properties led to the design of new alloys with complex microstructures, predicting their safe forming limits and understanding their microstructural deformation mechanisms remain as significant challenges largely due to the

  20. Simulation of Deformation Texture Evolution During Multi Axial Forging of Interstitial Free Steel

    Science.gov (United States)

    Gurao, N. P.; Kumar, P.; Sarkar, A.; Brokmeier, H.-G.; Suwas, Satyam

    2013-04-01

    Bulk texture measurement of multi-axial forged body center cubic interstitial free steel performed in this study using x-ray and neutron diffraction indicated the presence of a strong {101} single texture component. Viscoplastic self-consistent simulations could successfully predict the formation of this texture component by incorporating the complicated strain path followed during this process and assuming the activity of {101} slip system. In addition, a first-order estimate of mechanical properties in terms of highly anisotropic yield locus and Lankford parameter was also obtained from the simulations.

  1. Nuclear Phase Transition from Spherical to Axially Symmetric Deformed Shapes Using Interacting Boson Model

    Directory of Open Access Journals (Sweden)

    Khalaf A. M.

    2015-04-01

    Full Text Available The interacting boson model (sd-IBM1 with intrinsic coherent state is used to study the shape phase transitions from spherical U(5 to prolate deformed SU(3 shapes in Nd- Sm isotopic chains. The Hamiltonian is written in the creation and annihilation form with one and two body terms.For each nucleus a fitting procedure is adopted to get the best model parameters by fitting selected experimental energy levels, B(E2 transi- tion rates and two-neutron separation energies with the calculated ones.The U(5-SU(3 IBM potential energy surfaces (PES’s are analyzed and the critical phase transition points are identified in the space of model parameters.In Nd-Sm isotopic chains nuclei evolve from spherical to deformed shapes by increasing the boson number. The nuclei 150 Nd and 152 Sm have been found to be close to critical points.We have also studied the energy ratios and the B(E2 values for yrast band at the critical points.

  2. Enantioselective cascade reactions of stable sulfur ylides and nitroolefins through an axial-to-central chirality transfer strategy.

    Science.gov (United States)

    Lu, Liang-Qiu; Ming, Zhi-Hui; An, Jing; Li, Chao; Chen, Jia-Rong; Xiao, Wen-Jing

    2012-01-20

    An enantioselective [4 + 1] annulation/rearrangement cascade of stable sulfur ylides and nitroolefins has been developed through an efficient axial-to-central chirality transfer with the use of a chiral BINOL-derived sulfide as a reliable stereocontroller. It can provide pharmaceutically and synthetically important oxazolidinones in high stereoselectivities (up to 96:4 e.r. and >95:5 d.r.). Moreover, this strategy was also successfully applied to the asymmetric [4 + 1]/[3 + 2] cycloaddition cascade of sulfur ylides with alkene-tethered nitroolefins, and the corresponding enantioenriched fused heterocycles (up to 87:13 e.r. and >95:5 d.r.) were obtained in good to excellent yields (54-95% yields).

  3. Parallel-Distributed Model Deformation in the Fingertips for Stable Grasping and Object Manipulation

    Directory of Open Access Journals (Sweden)

    R. García-Rodríguez

    2012-01-01

    Full Text Available The study on the human grip has inspired to the robotics over the past decades, which has resulted in performance improvements of robotic hands. However, current robotic hands do not have the enough dexterity to execute complex tasks. Recognizing this fact, the soft fingertips with hemispherical shape and deformation models have renewed attention of roboticists. A high-friction contact to prevent slipping and the rolling contribution between the object and fingers are some characteristics of the soft fingertips which are useful to improve the grasping stability. In this paper, the parallel distributed deformation model is used to present the dynamical model of the soft tip fingers with n-degrees of freedom. Based on the joint angular positions of the fingers, a control scheme that fuses a stable grasping and the object manipulation into a unique control signal is proposed. The force-closure conditions are defined to guarantee a stable grasping and the boundedness of the closed-loop signals is proved. Furthermore, the convergence of the contact force to its desired value is guaranteed, without any information about the radius of the fingertip. Simulation results are provided to visualize the stable grasping and the object manipulation, avoiding the gravity effect.

  4. A stable partitioned FSI algorithm for incompressible flow and deforming beams

    International Nuclear Information System (INIS)

    Li, L.; Henshaw, W.D.; Banks, J.W.; Schwendeman, D.W.; Main, A.

    2016-01-01

    An added-mass partitioned (AMP) algorithm is described for solving fluid–structure interaction (FSI) problems coupling incompressible flows with thin elastic structures undergoing finite deformations. The new AMP scheme is fully second-order accurate and stable, without sub-time-step iterations, even for very light structures when added-mass effects are strong. The fluid, governed by the incompressible Navier–Stokes equations, is solved in velocity-pressure form using a fractional-step method; large deformations are treated with a mixed Eulerian-Lagrangian approach on deforming composite grids. The motion of the thin structure is governed by a generalized Euler–Bernoulli beam model, and these equations are solved in a Lagrangian frame using two approaches, one based on finite differences and the other on finite elements. The key AMP interface condition is a generalized Robin (mixed) condition on the fluid pressure. This condition, which is derived at a continuous level, has no adjustable parameters and is applied at the discrete level to couple the partitioned domain solvers. Special treatment of the AMP condition is required to couple the finite-element beam solver with the finite-difference-based fluid solver, and two coupling approaches are described. A normal-mode stability analysis is performed for a linearized model problem involving a beam separating two fluid domains, and it is shown that the AMP scheme is stable independent of the ratio of the mass of the fluid to that of the structure. A traditional partitioned (TP) scheme using a Dirichlet–Neumann coupling for the same model problem is shown to be unconditionally unstable if the added mass of the fluid is too large. A series of benchmark problems of increasing complexity are considered to illustrate the behavior of the AMP algorithm, and to compare the behavior with that of the TP scheme. The results of all these benchmark problems verify the stability and accuracy of the AMP scheme. Results for

  5. Fluid–structure coupling analysis of deformation and stress in impeller of an axial-flow pump with two-way passage

    Directory of Open Access Journals (Sweden)

    Ji Pei

    2016-04-01

    Full Text Available Axial-flow pump with a two-way passage has been widely employed in irrigation and drainage projects. Because of the shape of the two-way inlet passage, the impeller easily induces vibration due to unstable turbulent flow. This vibration results in structural cracks and even hinders the safe operation of the pump. Deformation and stress distributions in the impeller were calculated using two-way coupled fluid–structure interaction simulations, and a quantitative analysis of blade deformation and stress is carried out to determine the structure critical region. The results show that the values of deformation and stress significantly decrease with an increasing flow rate and a decreasing head, and the maximum total deformation can be found in the impeller rim, while the maximum equivalent stress can be obtained near the impeller hub. The total deformations in the blade rim decrease from blade leading edge to trailing edge, and the equivalent stress in the blade hub initially increases and then declines, and in the end, it rapidly increases from the blade outlet to inlet. These results reveal the deformation and stress in the impeller to ensure reliability and specific theoretical guidance for the structural optimization design of a pump device.

  6. Tuning the electronic properties of boron nitride nanotube by mechanical uni-axial deformation: a DFT study

    Directory of Open Access Journals (Sweden)

    Ju Shin-Pon

    2011-01-01

    Full Text Available Abstract The effect of uni-axial strain on the electronic properties of (8,0 zigzag and (5,5 armchair boron nitride nanotubes (BNNT is addressed by density functional theory calculation. The stress-strain profiles indicate that these two BNNTS of differing types display very similar mechanical properties, but there are variations in HOMO-LUMO gaps at different strains, indicating that the electronic properties of BNNTs not only depend on uni-axial strain, but on BNNT type. The variations in nanotube geometries, partial density of states of B and N atoms, B and N charges are also discussed for (8,0 and (5,5 BNNTs at different strains.

  7. Axial distribution of deformation in the cladding of pressurized water reactor fuel rods in a loss-of-coolant accident

    International Nuclear Information System (INIS)

    Rose, K.M.; Mann, C.A.; Hindle, E.D.

    1979-01-01

    In the event of a loss-of-coolant accident in a pressurized water reactor, the cladding of the fuel rods would undergo a temperature excursion while being subject to tensile hoop stress. The deformation behavior of 470-mm lengths of Zircaloy-4 fuel cladding has been studied experimentally; under a range of stress levels in the high-alpha range of zirconium (600 to 850 0 C), diametral strains of up to 70% were observed over the greater part of their length. A negative-feedback mechanism is suggested, based on the reduction of secondary creep rate following cooling by enhanced heat loss at swelling areas. An approximate analysis based on this mechanism was found to be in reasonable agreement with the experimental results. A computer modeling code is being developed to predict cladding deformation under realistic conditions

  8. Axial distribution of deformation in the cladding of pressurized water reactor fuel rods in a loss-of-coolant accident

    Energy Technology Data Exchange (ETDEWEB)

    Rose, K.M.; Mann, C.A.; Hindle, E.D.

    1979-12-01

    In the event of a loss-of-coolant accident in a pressurized water reactor, the cladding of the fuel rods would undergo a temperature excursion while being subject to tensile hoop stress. The deformation behavior of 470-mm lengths of Zircaloy-4 fuel cladding has been studied experimentally; under a range of stress levels in the high-alpha range of zirconium (600 to 850/sup 0/C), diametral strains of up to 70% were observed over the greater part of their length. A negative-feedback mechanism is suggested, based on the reduction of secondary creep rate following cooling by enhanced heat loss at swelling areas. An approximate analysis based on this mechanism was found to be in reasonable agreement with the experimental results. A computer modeling code is being developed to predict cladding deformation under realistic conditions.

  9. Introduction of the deformed base AMD and application to the stable and unstable nuclei

    International Nuclear Information System (INIS)

    Kimura, M.; Horiuchi, H.

    2003-01-01

    A new theoretical framework named as deformed base antisymmetrized molecular dynamics is presented. The theoretical framework enables us to describe sufficiently well the deforemd mean-field structure, cluster structure and their mixed structure within the same framework. Indeed the coexistence and mixture of the deformed mean-field structure and the cluster structure in the low-lying rotational bands of 20 Ne are described well. The possible existence of the cluster core + valance neutron structure in the K π =0 3 + band of 30 Ne is shown as well as the reasonable description of the observed properties of the ground bands of 30 Ne and 32 Mg

  10. 3D deformation field in growing plant roots reveals both mechanical and biological responses to axial mechanical forces.

    Science.gov (United States)

    Bizet, François; Bengough, A Glyn; Hummel, Irène; Bogeat-Triboulot, Marie-Béatrice; Dupuy, Lionel X

    2016-10-01

    Strong regions and physical barriers in soils may slow root elongation, leading to reduced water and nutrient uptake and decreased yield. In this study, the biomechanical responses of roots to axial mechanical forces were assessed by combining 3D live imaging, kinematics and a novel mechanical sensor. This system quantified Young's elastic modulus of intact poplar roots (32MPa), a rapid 3D. Measured critical elongation force was accurately predicted from an Euler buckling model, indicating that no biologically mediated accommodation to mechanical forces influenced bending during this short period of time. Force applied by growing roots increased more than 15-fold when buckling was prevented by lateral bracing of the root. The junction between the growing and the mature zones was identified as a zone of mechanical weakness that seemed critical to the bending process. This work identified key limiting factors for root growth and buckling under mechanical constraints. The findings are relevant to crop and soil sciences, and advance our understanding of root growth in heterogeneous structured soils. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  11. The effect of 210Pb and stable lead on the induction of mouthpart deformities in chironomid larvae

    International Nuclear Information System (INIS)

    Bird, G.A.; Schwartz, W.J.; Hoffman, D.

    1995-07-01

    To determine whether mouthpart deformities in chironomid larvae from Port Hope Harbour, Ontario, are the result of exposure to ionizing radiation or heavy metals in the sediment, Chironomus tentans larvae were exposed in the laboratory to concentrations of 210 Pb and stable lead representative of contaminant levels in the harbour. Exposure to 100, 1000, and 2000 Bq 210 Pb·g -1 dry sediment had no effect on the survival, growth of the larvae or frequency of deformities. Likewise, exposure to 0.5 and 5.0 mg lead·g -1 dry sediment had no effect on the larvae, but exposure to 35.0 mg lead·g -1 dry sediment resulted in 100% mortality of the larvae. These results indicate that the observed mouthpart deformities in chironomid larvae in Port Hope Harbour are not the result of radiation exposure. They also indicate that heavy metals (lead) may be having an impact on the population. (author). 28 refs., 9 tabs., 4 figs

  12. [The effects of coronary artery disease severity on left atrial deformation parameters in patients with stable coronary artery disease].

    Science.gov (United States)

    Kalaycı, Arzu; Karabay, Can Yücel; Taşar, Onur; İzci, Servet; Geçmen, Çetin; Oduncu, Vecih; İzgi, İbrahim Akın; Kırma, Cevat

    2017-03-01

    Aim of the present study was to investigate correlation between left atrial (LA) deformation parameters assessed using 2-dimensional (2D) speckle tracking echocardiography (STE) and complexity of coronary artery disease according to SYNTAX score (SXscore) in patients with stable coronary artery disease (SCAD). Total of 60 moderate-risk SCAD patients (40 men, 20 women) who underwent coronary angiography and 30 healthy controls were included. Measurements of conventional echocardiographic parameters as well as peak LA strain during ventricular systole (LA-RES), peak LA strain during atrial systole (LA-PUMP), peak LA strain rate during ventricular systole (LA-SRS), peak LA strain rate during early diastole (LA-SRE), and peak LA strain rate during atrial systole (LA-SRA) were obtained. Patients were categorized into 2 groups: low SXscore of SCAD who have high SXscore. In addition, evaluation of LA-RES and LA-PUMP functions might be useful in estimating severity of disease in patients with SCAD.

  13. Application of RNA Stable Isotope Probing (SIP) to Link Community Activity with Microorganisms Responsible for Autotrophy in the Subseafloor at Axial Seamount

    Science.gov (United States)

    Huber, J. A.; Fortunato, C. S.

    2014-12-01

    The global ocean comprises the Earth's largest biome, with microorganisms playing a dominant biogeochemical role. However, the potential for production of new microbial biomass within the subseafloor is rarely considered in traditional oceanographic paradigms of carbon cycling or microbial food webs. In this study, we used RNA Stable Isotope Probing (RNA SIP) to determine the microbial community composition and genetic repertoire of active subseafloor autotrophs in warm venting fluids from Axial Seamount. RNA is a responsive biomarker because it is a reflection of cellular activity independent of replication, and RNA SIP thus provides access to both the function of a microbial community and the phylogeny of the organisms accountable for key functions. Diffuse fluids were incubated shipboard at 30°C, 55°C, and 80°C with 13DIC and H2. Metatranscriptomic sequencing of both the enriched and non-enriched RNA was carried out from 13C and 12C controls. In addition, filtered fluid samples were preserved in situ for comparative meta -transcriptomic and -genomic analyses. Diverse lineages of bacteria and archaea and accompanying metabolisms were detected in situ, but RNA SIP results show dominance of three different groups of autotrophs active under each experimental condition. At 30°C, members of the Sulfurimonas genus dominated, with genes for hydrogen oxidation, nitrate reduction, and carbon fixation via the rTCA cycle highly expressed. At 55°C, both Caminibacter and Nautilia transcripts were detected for rTCA cycle, hydrogen oxidation, and nitrate reduction. At 80°C, transcripts for hydrogenotrophic methanogenesis mediated by members of Methanocaldococcus were detected. These results suggest the subseafloor hosts various anaerobic chemolithoautotrophs that span a wide temperature range, with hydrogen playing a key role in microbial metabolism. Complementary experiments are currently being carried out on the seafloor with a novel in situ incubator unit to provide

  14. Structurally Deformed MoS2 for Electrochemically Stable, Thermally Resistant, and Highly Efficient Hydrogen Evolution Reaction.

    Science.gov (United States)

    Chen, Yen-Chang; Lu, Ang-Yu; Lu, Ping; Yang, Xiulin; Jiang, Chang-Ming; Mariano, Marina; Kaehr, Bryan; Lin, Oliver; Taylor, André; Sharp, Ian D; Li, Lain-Jong; Chou, Stanley S; Tung, Vincent

    2017-11-01

    The emerging molybdenum disulfide (MoS 2 ) offers intriguing possibilities for realizing a transformative new catalyst for driving the hydrogen evolution reaction (HER). However, the trade-off between catalytic activity and long-term stability represents a formidable challenge and has not been extensively addressed. This study reports that metastable and temperature-sensitive chemically exfoliated MoS 2 (ce-MoS 2 ) can be made into electrochemically stable (5000 cycles), and thermally robust (300 °C) while maintaining synthetic scalability and excellent catalytic activity through physical-transformation into 3D structurally deformed nanostructures. The dimensional transition enabled by a high throughput electrohydrodynamic process provides highly accessible, and electrochemically active surface area and facilitates efficient transport across various interfaces. Meanwhile, the hierarchically strained morphology is found to improve electronic coupling between active sites and current collecting substrates without the need for selective engineering the electronically heterogeneous interfaces. Specifically, the synergistic combination of high strain load stemmed from capillarity-induced-self-crumpling and sulfur (S) vacancies intrinsic to chemical exfoliation enables simultaneous modulation of active site density and intrinsic HER activity regardless of continuous operation or elevated temperature. These results provide new insights into how catalytic activity, electrochemical-, and thermal stability can be concurrently enhanced through the physical transformation that is reminiscent of nature, in which properties of biological materials emerge from evolved dimensional transitions. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Structurally Deformed MoS2 for Electrochemically Stable, Thermally Resistant, and Highly Efficient Hydrogen Evolution Reaction

    KAUST Repository

    Chen, Yen-Chang

    2017-10-12

    The emerging molybdenum disulfide (MoS2) offers intriguing possibilities for realizing a transformative new catalyst for driving the hydrogen evolution reaction (HER). However, the trade-off between catalytic activity and long-term stability represents a formidable challenge and has not been extensively addressed. This study reports that metastable and temperature-sensitive chemically exfoliated MoS2 (ce-MoS2) can be made into electrochemically stable (5000 cycles), and thermally robust (300 °C) while maintaining synthetic scalability and excellent catalytic activity through physical-transformation into 3D structurally deformed nanostructures. The dimensional transition enabled by a high throughput electrohydrodynamic process provides highly accessible, and electrochemically active surface area and facilitates efficient transport across various interfaces. Meanwhile, the hierarchically strained morphology is found to improve electronic coupling between active sites and current collecting substrates without the need for selective engineering the electronically heterogeneous interfaces. Specifically, the synergistic combination of high strain load stemmed from capillarity-induced-self-crumpling and sulfur (S) vacancies intrinsic to chemical exfoliation enables simultaneous modulation of active site density and intrinsic HER activity regardless of continuous operation or elevated temperature. These results provide new insights into how catalytic activity, electrochemical-, and thermal stability can be concurrently enhanced through the physical transformation that is reminiscent of nature, in which properties of biological materials emerge from evolved dimensional transitions.

  16. Dynamic Metasomatism: Stable Isotopes, Fluid Evolution, and Deformation of Albitite and Scapolite Metagabbro (Bamble Lithotectonic Domain, South Norway

    Directory of Open Access Journals (Sweden)

    Ane K. Engvik

    2018-01-01

    Full Text Available New stable isotopic data from mineral separates of albite, scapolite, amphibole, quartz, and calcite of metasomatic rocks (Bamble lithotectonic domain give increased knowledge on fluid type, source, and evolution during metamorphism. Albite from a variety of albitites gives δ18OSMOW values of 5.1–11.1‰, while quartz from clinopyroxene-bearing albitite gives 11.5–11.6‰. δ18OSMOW values for calcite samples varies between 3.4 and 12.4‰ and shows more consistent δ13C values of −4.6 to -6.0‰. Amphibole from scapolite metagabbro yields a δ18OSMOW value of 4.3 to 6.7‰ and δDSMOW value of −84 to −50‰, while the scapolite gives δ18OSMOW values in the range of 7.4 to 10.6‰. These results support the interpretation that the original magmatic rocks were metasomatised by seawater solutions with a possible involvement from magmatic fluids. Scapolitisation and albitisation led to contrasting chemical evolution with respect to elements like P, Ti, V, Fe, and halogens. The halogens deposited as Cl-scapolite were dissolved by albitisation fluid and reused as a ligand for metal transport. Many of the metal deposits in the Bamble lithotectonic domain, including Fe-ores, rutile, and apatite deposits formed during metasomatism. Brittle to ductile deformation concurrent with metasomatic infiltration illustrates the dynamics and importance of metasomatic processes during crustal evolution.

  17. Axial myopathy

    DEFF Research Database (Denmark)

    Witting, Nanna; Andersen, Linda K; Vissing, John

    2016-01-01

    Classically, myopathies are categorized according to limb or cranial nerve muscle affection, but with the growing use of magnetic resonance imaging it has become evident that many well-known myopathies have significant involvement of the axial musculature. New disease entities with selective axial...

  18. Axial spondyloarthritis.

    Science.gov (United States)

    Sieper, Joachim; Braun, Jürgen; Dougados, Maxime; Baeten, Dominique

    2015-07-09

    The term axial spondyloarthritis covers both non-radiographic disease and radiographic disease (also known as ankylosing spondylitis). Some studies have been performed to investigate the prevalence of axial spondyloarthritis, although most are limited to patients with radiographic disease. A strong genetic association has been shown between axial spondyloarthritis and human leukocyte antigen-B27 (HLA-B27), but the pathogenetic role of HLA-B27 has not yet been clarified. Tumour necrosis factor (TNF), IL-17, IL-23 and downstream pathways also seem to be important - based on the good results of therapies directed against these molecules - but their exact role in the inflammatory process is also not yet clear. Elucidating the interaction between osteoproliferation and inflammation will be crucial for the prevention of long-term structural damage of the bone. The development of new criteria for classification, diagnosis and screening of patients with axial spondyloarthritis will enable earlier intervention for this chronic inflammatory disease. MRI has become an important tool for the early detection of axial spondyloarthritis. NSAIDs and TNF blockers are effective therapies, including in the early non-radiographic stage. Therapeutic blockade of IL-17 or IL-23 seems to be a promising new treatment option. Tools for measuring quality of life in axial spondyloarthritis have become relevant to assess the impact that the disease has on patients. These diagnostic and therapeutic advances will continue to change the management of axial spondyloarthritis, and new insights into the disease pathogenesis will hopefully accelerate this process. For an illustrated summary of this Primer, visit: http://go.nature.com/51b1af.

  19. Moving towards high-power, high-frequency and low-resistance CNT supercapacitors by tuning the CNT length, axial deformation and contact resistance

    Science.gov (United States)

    Basiricò, L.; Lanzara, G.

    2012-08-01

    In this paper it is shown that the electrochemical behaviour of vertically aligned multi-walled carbon nanotube (VANT) supercapacitors is influenced by the VANTs’ length (electrode thickness), by their axial compression and by their interface with the current collector. It is found that the VANTs, which can be interpreted as a dense array of nanochannels, have an active area available to ions that is strongly affected by the electrode’s thickness and compressional state. Consequently, the tested thinner electrodes, compressed electrodes or a combination of the two were found to be characterized by a significant improvement in terms of power density (up to 1246%), knee frequency (58 822% working up to 10 kHz), equivalent series resistance (ESR, up to 67%) and capacitance (up to 21%) when compared with thicker and/or uncompressed electrodes. These values are significantly higher than those reported in the literature where long VANTs with no control on compression are typically used. It is also shown that the ESR can be reduced not only by using shorter and compressed VANTs that have a higher conductance or by improving the electrode/collector electrical contact by changing the contact morphology at the nanoscale through compression, but also by depositing a thin platinum layer on the VANT tips in contact with the current collector (73% ESR decrease).

  20. Axially deformed solution of the Skyrme-Hartree-Fock-Bogoliubov equations using the transformed harmonic oscillator basis (II) HFBTHO v2.00d: A new version of the program

    Science.gov (United States)

    Stoitsov, M. V.; Schunck, N.; Kortelainen, M.; Michel, N.; Nam, H.; Olsen, E.; Sarich, J.; Wild, S.

    2013-06-01

    We describe the new version 2.00d of the code HFBTHO that solves the nuclear Skyrme-Hartree-Fock (HF) or Skyrme-Hartree-Fock-Bogoliubov (HFB) problem by using the cylindrical transformed deformed harmonic oscillator basis. In the new version, we have implemented the following features: (i) the modified Broyden method for non-linear problems, (ii) optional breaking of reflection symmetry, (iii) calculation of axial multipole moments, (iv) finite temperature formalism for the HFB method, (v) linear constraint method based on the approximation of the Random Phase Approximation (RPA) matrix for multi-constraint calculations, (vi) blocking of quasi-particles in the Equal Filling Approximation (EFA), (vii) framework for generalized energy density with arbitrary density-dependences, and (viii) shared memory parallelism via OpenMP pragmas. Program summaryProgram title: HFBTHO v2.00d Catalog identifier: ADUI_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADUI_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 167228 No. of bytes in distributed program, including test data, etc.: 2672156 Distribution format: tar.gz Programming language: FORTRAN-95. Computer: Intel Pentium-III, Intel Xeon, AMD-Athlon, AMD-Opteron, Cray XT5, Cray XE6. Operating system: UNIX, LINUX, WindowsXP. RAM: 200 Mwords Word size: 8 bits Classification: 17.22. Does the new version supercede the previous version?: Yes Catalog identifier of previous version: ADUI_v1_0 Journal reference of previous version: Comput. Phys. Comm. 167 (2005) 43 Nature of problem: The solution of self-consistent mean-field equations for weakly-bound paired nuclei requires a correct description of the asymptotic properties of nuclear quasi-particle wave functions. In the present implementation, this is achieved by using the single-particle wave functions

  1. Filtering of high modal frequencies for stable real-time explicit integration of deformable objects using the Finite Element Method.

    Science.gov (United States)

    Aguinaga, Iker; Fierz, Basil; Spillmann, Jonas; Harders, Matthias

    2010-12-01

    The behavior, performance, and run-time of mechanical simulations in interactive virtual surgery depend heavily on the type of numerical differential equation solver used to integrate in time the dynamic equations obtained from simulation methods, such as the Finite Element Method. Explicit solvers are fast but only conditionally stable. The condition number of the stiffness matrix limits the highest possible time step. This limit is related to the geometrical properties of the underlying mesh, such as element shape and size. In fact, it can be governed by a small set of ill-shaped elements. For many applications this issue can be solved a priori by a careful meshing. However, when meshes are cut during interactive surgery simulation, it is difficult and computationally expensive to control the quality of the resulting elements. As an alternative, we propose to modify the elemental stiffness matrices directly in order to ensure stability. In this context, we first investigate the behavior of the eigenmodes of the elemental stiffness matrix in a Finite Element Method. We then propose a simple filter to reduce high model frequencies and thus allow larger time steps, while maintaining the general mechanical behavior. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Axially deformed solution of the Skyrme-Hartree-Fock-Bogolyubov equations using the transformed harmonic oscillator basis (III) HFBTHO (v3.00): A new version of the program

    Science.gov (United States)

    Perez, R. Navarro; Schunck, N.; Lasseri, R.-D.; Zhang, C.; Sarich, J.

    2017-11-01

    We describe the new version 3.00 of the code HFBTHO that solves the nuclear Hartree-Fock (HF) or Hartree-Fock-Bogolyubov (HFB) problem by using the cylindrical transformed deformed harmonic oscillator basis. In the new version, we have implemented the following features: (i) the full Gogny force in both particle-hole and particle-particle channels, (ii) the calculation of the nuclear collective inertia at the perturbative cranking approximation, (iii) the calculation of fission fragment charge, mass and deformations based on the determination of the neck, (iv) the regularization of zero-range pairing forces, (v) the calculation of localization functions, (vi) a MPI interface for large-scale mass table calculations. Program Files doi:http://dx.doi.org/10.17632/c5g2f92by3.1 Licensing provisions: GPL v3 Programming language: FORTRAN-95 Journal reference of previous version: M.V. Stoitsov, N. Schunck, M. Kortelainen, N. Michel, H. Nam, E. Olsen, J. Sarich, and S. Wild, Comput. Phys. Commun. 184 (2013). Does the new version supersede the previous one: Yes Summary of revisions: 1. the Gogny force in both particle-hole and particle-particle channels was implemented; 2. the nuclear collective inertia at the perturbative cranking approximation was implemented; 3. fission fragment charge, mass and deformations were implemented based on the determination of the position of the neck between nascent fragments; 4. the regularization method of zero-range pairing forces was implemented; 5. the localization functions of the HFB solution were implemented; 6. a MPI interface for large-scale mass table calculations was implemented. Nature of problem:HFBTHO is a physics computer code that is used to model the structure of the nucleus. It is an implementation of the energy density functional (EDF) approach to atomic nuclei, where the energy of the nucleus is obtained by integration over space of some phenomenological energy density, which is itself a functional of the neutron and proton

  3. Light axial vector mesons

    Science.gov (United States)

    Chen, Kan; Pang, Cheng-Qun; Liu, Xiang; Matsuki, Takayuki

    2015-04-01

    Inspired by the abundant experimental observation of axial-vector states, we study whether the observed axial-vector states can be categorized into the conventional axial-vector meson family. In this paper we carry out an analysis based on the mass spectra and two-body Okubo-Zweig-Iizuka-allowed decays. Besides testing the possible axial-vector meson assignments, we also predict abundant information for their decays and the properties of some missing axial-vector mesons, which are valuable for further experimental exploration of the observed and predicted axial-vector mesons.

  4. Computed tomographic myelography (CTM) in atlanto-axial rheumatoid arthritis

    International Nuclear Information System (INIS)

    Laasonen, E.M.; Servo, A.; Kankaanpaeae, U.; Paukku, P.; Sandelin, J.; Slaetis, P.

    1985-01-01

    Thirty-two patients with severe cervical rheumatoid arthritis were investigated preoperatively with cervical myelography (CeM) and computed tomographic myelography (CTM). The severity of their clinical symptoms correlated excellently with a combination of the deformation of the spinal cord at the atlanto-axial level, the lateral dislocation of the cord at the same level, and the deformation of the cord at some lower cervical level. Obstructing softtissue excrescences seemed to have little value. No correlation was found in this study between the deformation of the cord and the main findings of the plain films: the atlanto-axial subluxation (AAS), the vertical subluxation (VS), or their combination. (orig.)

  5. Axial static mixer

    Science.gov (United States)

    Sandrock, H.E.

    1982-05-06

    Static axial mixing apparatus includes a plurality of channels, forming flow paths of different dimensions. The axial mixer includes a flow adjusting device for adjustable selective control of flow resistance of various flow paths in order to provide substantially identical flows through the various channels, thereby reducing nonuniform coating of interior surfaces of the channels. The flow adjusting device may include diaphragm valves, and may further include a pressure regulating system therefor.

  6. Extremely deformable structures

    CERN Document Server

    2015-01-01

    Recently, a new research stimulus has derived from the observation that soft structures, such as biological systems, but also rubber and gel, may work in a post critical regime, where elastic elements are subject to extreme deformations, though still exhibiting excellent mechanical performances. This is the realm of ‘extreme mechanics’, to which this book is addressed. The possibility of exploiting highly deformable structures opens new and unexpected technological possibilities. In particular, the challenge is the design of deformable and bi-stable mechanisms which can reach superior mechanical performances and can have a strong impact on several high-tech applications, including stretchable electronics, nanotube serpentines, deployable structures for aerospace engineering, cable deployment in the ocean, but also sensors and flexible actuators and vibration absorbers. Readers are introduced to a variety of interrelated topics involving the mechanics of extremely deformable structures, with emphasis on ...

  7. Axial tomographic scanner

    International Nuclear Information System (INIS)

    1976-01-01

    An axial tomographic system is described comprising axial tomographic means for collecting sets of data corresponding to the transmission or absorption of a number of beams of penetrating radiation through a planar slice of an object. It includes means to locate an object to be analyzed, a source and detector for directing one or more beams of penetrating radiation through the object from the source to the detector, and means to rotate (and optionally translate) the source as well as means to process the collected sets of data. Data collection, data processing, and data display can each be conducted independently of each other. An additional advantage of the system described is that the raw data (i.e., the originally collected data) are not destroyed by the data processing but instead are retained intact for further reference or use, if needed

  8. Cladding axial elongation models for FRAP-T6

    International Nuclear Information System (INIS)

    Shah, V.N.; Carlson, E.R.; Berna, G.A.

    1983-01-01

    This paper presents a description of the cladding axial elongation models developed at the Idaho National Engineering Laboratory (INEL) for use by the FRAP-T6 computer code in analyzing the response of fuel rods during reactor transients in light water reactors (LWR). The FRAP-T6 code contains models (FRACAS-II subcode) that analyze the structural response of a fuel rod including pellet-cladding-mechanical-interaction (PCMI). Recently, four models were incorporated into FRACAS-II to calculate cladding axial deformation: (a) axial PCMI, (b) trapped fuel stack, (c) fuel relocation, and (d) effective fuel thermal expansion. Comparisons of cladding axial elongation measurements from two experiments with the corresponding FRAP-T6 calculations are presented

  9. Compton backscattering axial spectrometer

    International Nuclear Information System (INIS)

    Rad'ko, V.E.; Mokrushin, A.D.; Razumovskaya, I.V.

    1981-01-01

    Compton gamma backscattering axial spectrometer of new design with the 200 time larger aperture as compared with the known spectrometers at the equal angular resolution (at E=159 keV) is described. Collimator unit, radiation source and gamma detector are located in the central part of the spectrometer. The investigated specimen (of cylindrical form) and the so called ''black body'' used for absorption of photons, passed through the specimen are placed in the peripheric part. Both these parts have an imaginary symmetry axis that is why the spectrometer is called axial. 57 Co is used as the gamma source. The 122 keV spectral line which corresponds to the 83 keV backscattered photon serves as working line. Germanium disk detector of 10 mm diameter and 4 mm height has energy resolution not worse than 900 eV. The analysis of results of test measurements of compton water profile and their comparison with data obtained earlier show that only finity of detector resolution can essentially affect the form of Compton profile. It is concluded that the suggested variant of the spectrometer would be useful for determination of Compton profiles of chemical compounds of heavy elements [ru

  10. Light-front view of the axial anomaly

    International Nuclear Information System (INIS)

    Ji, C.; Rey, S.

    1996-01-01

    Motivated by an apparent puzzle of the light-front vacua incompatible with the axial anomaly, we have considered the two-dimensional massless Schwinger model for an arbitrary interpolating angle of Hornbostel close-quote s interpolating quantization surface. By examining spectral deformation of the Dirac sea under an external electric field semiclassically, we have found that the axial anomaly is quantization angle independent. This indicates an intricate nontrivial vacuum structure present even in the light-front limit. copyright 1996 The American Physical Society

  11. Axial skeletal CT densitometry

    International Nuclear Information System (INIS)

    Lampmann, L.E.H.

    1982-01-01

    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.)

  12. Reactive control of subsonic axial fan noise in a duct.

    Science.gov (United States)

    Liu, Y; Choy, Y S; Huang, L; Cheng, L

    2014-10-01

    Suppressing the ducted fan noise at low frequencies without varying the flow capacity is still a technical challenge. This study examines a conceived device consisting of two tensioned membranes backed with cavities housing the axial fan for suppression of the sound radiation from the axial fan directly. The noise suppression is achieved by destructive interference between the sound fields from the axial fan of a dipole nature and sound radiation from the membrane via vibroacoustics coupling. A two-dimensional model with the flow effect is presented which allows the performance of the device to be explored analytically. The air flow influences the symmetrical behavior and excites the odd in vacuo mode response of the membrane due to kinematic coupling. Such an asymmetrical effect can be compromised with off-center alignment of the axial fan. Tension plays an important role to sustain the performance to revoke the deformation of the membrane during the axial fan operation. With the design of four appropriately tensioned membranes covered by a cylindrical cavity, the first and second blade passage frequencies of the axial fan can be reduced by at least 20 dB. The satisfactory agreement between experiment and theory demonstrates that its feasibility is practical.

  13. Axial elongation following prolonged near work in myopes and emmetropes.

    Science.gov (United States)

    Woodman, Emily C; Read, Scott A; Collins, Michael J; Hegarty, Katherine J; Priddle, Scott B; Smith, Josephine M; Perro, Judd V

    2011-05-01

    To investigate the influence of a period of sustained near work upon axial length in groups of emmetropes (EMM) and myopes. Forty young adult subjects (20 myopes and 20 emmetropes) were recruited for the study. Myopes were further classified as early onset (EOM), late onset (LOM), stable (SM) or progressing (PM) subgroups. Axial length was measured with the IOLMaster instrument before, immediately after and then again 10 min after a continuous 30 min near task of 5 D accommodation demand. Measures of distance objective refraction were also collected. Significant changes in axial length were observed immediately following the near task. EOM axial length elongated on average by 0.027±0.021 mm, LOM by 0.014±0.020 mm, EMM by 0.010±0.015 mm, PM by 0.031±0.022 mm and SM by 0.014±0.018 mm. At the conclusion of the 10 min regression period, axial length measures were not significantly different from baseline values. Axial elongation was observed following a prolonged near task. Both EOM and PM groups showed increases in axial length that were significantly greater than emmetropes.

  14. Deformation microstructures

    DEFF Research Database (Denmark)

    Hansen, N.; Huang, X.; Hughes, D.A.

    2004-01-01

    Microstructural characterization and modeling has shown that a variety of metals deformed by different thermomechanical processes follows a general path of grain subdivision, by dislocation boundaries and high angle boundaries. This subdivision has been observed to very small structural scales...

  15. Thermocapillary Convection in Floating Zone with Axial Magnetic Fields

    Science.gov (United States)

    Liang, Ruquan; Yang, Shuo; Li, Jizhao

    2014-02-01

    Numerical simulations on the effects of axial magnetic fields on the thermocapillary convection in a liquid bridge of silicone-oil-based ferrofluid under zero gravity have been conducted. The Navier-Stokes equations coupled with the energy conservation equation are solved on a staggered grid, and the mass conserving level set approach is used to capture the free surface deformation of the liquid bridge. The obvious effects of the magnetic fields on the flow pattern as well as the velocity and temperature distributions in the liquid bridge can be detected. The axial magnetic fields suppress the thermocapillary convection and a stagnant flow zone is formed between the circulating flow and the symmetric axis as the magnetic fields increase. The axial magnetic fields affect not only the velocity level inside the liquid bridge but also the velocity level on the free surface. The temperature contours near the free surface illustrates conduction-type temperature profiles at moderate strength fields.

  16. Partial Dynamical Symmetry in Deformed Nuclei

    International Nuclear Information System (INIS)

    Leviatan, A.

    1996-01-01

    We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial SU(3) symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei. copyright 1996 The American Physical Society

  17. Partial Dynamical Symmetry in Deformed Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A. [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)

    1996-07-01

    We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial SU(3) symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei. {copyright} {ital 1996 The American Physical Society.}

  18. DEFORMATION OF THE WALL OF THE ARTERY WITH TIME ...

    African Journals Online (AJOL)

    Investigation has been carried out to see how the presence of a growing stenosis affects the deformation of the wall of an artery in the pulsatile flow of blood. The expressions for the resulting deformations in the radial and axial directions were obtained. From analysis of these results, we noted that at the beginning of the ...

  19. Dissipative Axial Inflation

    CERN Document Server

    Notari, Alessio

    2016-12-22

    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...

  20. Preferred orientation of a naturally and experimentally deformed pyrrhotite ore by X-ray and neutron diffraction texture analysis

    International Nuclear Information System (INIS)

    Niederschlag, E.; Brokmeier, H.G.; Siemes, H.

    1994-01-01

    Two samples of polycrystalline naturally deformed hexagonal Pyrrhotite were deformed experimentally in axial compression tests with different temperatures and strain. The texture of the naturally deformed ore was investigated both by X-ray and neutron texture analyses. Texture measurements on the experimentally deformed ore were carried out by neutron diffraction. (orig.)

  1. Characterization of Multiflux Axial Compressors

    International Nuclear Information System (INIS)

    Brasnarof, Daniel; Kyung Kyu-Hyung; Rivarola, Martin; Gonzalez Jose; Florido, Pablo; Orellano, Pablo; Bergallo, Juan

    2003-01-01

    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

  2. Axial loading cross screw fixation for the Austin bunionectomy.

    Science.gov (United States)

    Rigby, Ryan B; Fallat, Lawrence M; Kish, John P

    2011-01-01

    The Austin procedure has become a common method of osteotomy for the correction of hallux abductovalgus when indicated. The V-type configuration is intrinsically stable but not without complications. One complication encountered is rotation and/or displacement of the capital fragment. We present the use of an axial loading screw in conjunction with a dorsally placed compression screw. The benefit to this technique lies in the orientation of the axial loading screw, because it is directed to resist the ground reactive forces while also providing a second point of fixation in a crossing screw design. In a head-to-head biomechanical comparison, we tested single dorsal screw fixation versus double screw fixation, including both the dorsal and the axial loading screws in 10 metatarsal Sawbones(®) (Pacific Research Laboratories Inc, Vashon, WA). Five metatarsals received single dorsal screw fixation and five received the dorsal screw and the additional axial loading screw. The metatarsals were analyzed on an Instron compression device for comparison; 100% of the single screw fixation osteotomies failed with compression at an average peak load of 205 N. Four of five axial loading double screw fixation osteotomies did not fail. This finding suggests that the addition of an axial loading screw providing cross screw orientation significantly increases the stability of the Austin osteotomy, ultimately decreasing the likelihood of displacement encountered in the surgical repair of hallux abductovalgus. Copyright © 2011 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  3. Stable isotopes

    International Nuclear Information System (INIS)

    Evans, D.K.

    1986-01-01

    Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

  4. Fluorescence axial nanotomography with plasmonics.

    Science.gov (United States)

    Cade, Nicholas I; Fruhwirth, Gilbert O; Krasavin, Alexey V; Ng, Tony; Richards, David

    2015-01-01

    We present a novel imaging technique with super-resolution axial sensitivity, exploiting the changes in fluorescence lifetime above a plasmonic substrate. Using conventional confocal fluorescence lifetime imaging, we show that it is possible to deliver down to 6 nm axial position sensitivity of fluorophores in whole biological cell imaging. We employ this technique to map the topography of the cellular membrane, and demonstrate its application in an investigation of receptor-mediated endocytosis in carcinoma cells.

  5. Relativistic description of deformed nuclei

    International Nuclear Information System (INIS)

    Price, C.E.

    1988-01-01

    The author has shown that relativistic Hartree calculations using parameters that have been fit to the properties of nuclear matter can provide a good description of both spherical and axially deformed nuclei. The quantitative agreement with experiment is equivalent to that which was obtained in non-relativistic calculations using Skyrme interactions. The equilibrium deformation is strongly correlated with the size of the spin-orbit splitting, and that parameter sets which give roughly the correct value for this splitting provide the best agreement with the quadrupole moments in the s-d shell. Finally, for closed shell +/- 1 nuclei, it was shown that the self-consistent calculations are able to reproduce the experimental magnetic moments. This was not possible in relativistic calculations which include only the effects of the valence orbital

  6. Comparative Finite Element Method Analysis of Spiroid Worm Gear Drives Having Arched Profile and Having Linear Profile in Axial Section

    Directory of Open Access Journals (Sweden)

    Sándor BODZÁS

    2013-12-01

    Full Text Available With the knowledge of the advantageous characteristics of the cylindrical worm gear drives having arched profile in axial section and the conical worm gear drives having linear profile in axial section, a new geometric type conical worm gear drive has been designed and then manufactured, that is the conical worm gear drive having arched profile in axial section. Beside similar charging and marginal conditions in case of the same geometric spiroid worm gear drives having arched profile and having linear profile in axial section we have done comparative finite element method analysis for awarding of the strains, deformations and stresses of this gear drives.

  7. Dual-channel phase-contrast spectral optical coherence tomography for simultaneously measuring axial and normal to B-scan off-axial displacements

    Science.gov (United States)

    Dong, Bo; Zhang, Yun; Ye, Shuangli; Zhou, Yanzhou; He, Zhaoshui; Xie, Shengli

    2017-09-01

    A dual-channel phase-contrast spectral optical coherence tomography (DPC-SOCT) method is proposed for measuring axial and normal to B-scan off-axial displacements inside weakly scattering translucent materials. By employing a dual-channel observation structure with depth multiplexing, only one shot before and one shot after the object deformation are required for simultaneously measuring the displacements. To validate the method, a DPC-SOCT system was built and axial and normal to B-scan off-axial displacements inside polymer films were measured at 20 frames per second. The results suggest that the method can be used for investigating inner mechanical properties of materials under different loads. In the future, a method for all orthogonal measurement of displacement components will be developed.

  8. Development and Testing of an Axial Halbach Magnetic Bearing

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2006-01-01

    The NASA Glenn Research Center has developed and tested a revolutionary Axial Halbach Magnetic Bearing. The objective of this work is to develop a viable non-contact magnetic thrust bearing utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help to reduce harmful emissions, reduce the Nation s dependence on fossil fuels and mitigate many of the concerns and limitations encountered in conventional axial bearings such as bearing wear, leaks, seals and friction loss. The Axial Halbach Magnetic Bearing is inherently stable and requires no active feedback control system or superconductivity as required in many magnetic bearing designs. The Axial Halbach Magnetic Bearing is useful for very high speed applications including turbines, instrumentation, medical systems, computer memory systems, and space power systems such as flywheels. Magnetic fields suspend and support a rotor assembly within a stator. Advanced technologies developed for particle accelerators, and currently under development for maglev trains and rocket launchers, served as the basis for this application. Experimental hardware was successfully designed and developed to validate the basic principles and analyses. The report concludes that the implementation of Axial Halbach Magnetic Bearings can provide significant improvements in rotational system performance and reliability.

  9. Studi Regangan Axial dan Lateral pada Tanah Ekspansif

    Directory of Open Access Journals (Sweden)

    Lisa Fitriyana

    2017-07-01

    Full Text Available Swelling and shrinkage abilities of soils are dangerous for buildings. According to Hardiyatmo (2014 There are two types of swelling in expansive soils that are the movement of lateral (horizontal and axial (vertical. Oftentimes the deformation of soils cannot be supported by building stiffness. This damage can be seen in retaining walls, tunnel walls, and etc. With the aims to identify an expansive soil and to know its lateral and axial strains, an experimental study was performed. Swelling tests were conducted in a specimen having diameter (d of 4,5 cm and height (h0 of 2 cm with the variations in : 1 water content wopt = 31% and 18%; 2 vertical pressure (pv 1 kPa, 3.5 kPa and 6.9 kPa; and 3 membrane thickness (t 0.7 mm and 0.5 mm. The strain in the axial direction was measured with a dial gauge that was set vertically parallel whereas the lateral strain is by measuring changes in diameter of the specimen with a digital caliper measurement tools. Based on the analysis on the identification results, the observed soil is classified as expansive soil with the expansion potential is high average. The test results show the same potential for the occurrence of lateral and lateral strain if the lateral retention (e.g. retaining wall is weak. The largest lateral and axial soil development occurred at water content w0 = 18% are 15.7% and 15.8% respectively.

  10. Deformation Microstructure in Beta-Titanium After Deformation at Low Temperatures

    National Research Council Canada - National Science Library

    Humphreys, F. J; Bate, P. S; Brough, I

    2005-01-01

    .... The contractor shall use a beta Ti alloy that is stable and single-phase at room temperature. The contractor shall evaluate the microstructure of the material after deformation at room temperature and at temperatures up to ̃400C...

  11. 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.

  12. Axial stability of Taylor bubbles

    NARCIS (Netherlands)

    Lu, X.; Prosperetti, Andrea

    2006-01-01

    Long gas bubbles rising in a vertical tube are observed to lose axial symmetry and become unstable in a downward liquid flow. In this paper an approximate linear stability analysis of this phenomenon is presented. It is found that, under the combined effect of gravity and the pressure gradient which

  13. Developing a Virtual Rock Deformation Laboratory

    Science.gov (United States)

    Zhu, W.; Ougier-simonin, A.; Lisabeth, H. P.; Banker, J. S.

    2012-12-01

    Experimental rock physics plays an important role in advancing earthquake research. Despite its importance in geophysics, reservoir engineering, waste deposits and energy resources, most geology departments in U.S. universities don't have rock deformation facilities. A virtual deformation laboratory can serve as an efficient tool to help geology students naturally and internationally learn about rock deformation. Working with computer science engineers, we built a virtual deformation laboratory that aims at fostering user interaction to facilitate classroom and outreach teaching and learning. The virtual lab is built to center around a triaxial deformation apparatus in which laboratory measurements of mechanical and transport properties such as stress, axial and radial strains, acoustic emission activities, wave velocities, and permeability are demonstrated. A student user can create her avatar to enter the virtual lab. In the virtual lab, the avatar can browse and choose among various rock samples, determine the testing conditions (pressure, temperature, strain rate, loading paths), then operate the virtual deformation machine to observe how deformation changes physical properties of rocks. Actual experimental results on the mechanical, frictional, sonic, acoustic and transport properties of different rocks at different conditions are compiled. The data acquisition system in the virtual lab is linked to the complied experimental data. Structural and microstructural images of deformed rocks are up-loaded and linked to different deformation tests. The integration of the microstructural image and the deformation data allows the student to visualize how forces reshape the structure of the rock and change the physical properties. The virtual lab is built using the Game Engine. The geological background, outstanding questions related to the geological environment, and physical and mechanical concepts associated with the problem will be illustrated on the web portal. In

  14. Stability of Axially Compressed Single-Cell Mono-Symmetric Thin ...

    African Journals Online (AJOL)

    Compared with conventional structural columns, the pronounced role of instabilities complicates the behaviour and design of thin-walled columns. This study investigated the stability of axially compressed single-cell thin-walled column with mono-symmetric non-deformable cross-sections. The work involved a theoretical ...

  15. Axial current matrix elements of the nucleon based on an exact diagonalization of the SU(3) Skyrme model hamiltonian

    International Nuclear Information System (INIS)

    Park, N.W.; Schechter, J.; Weigel, H.

    1989-01-01

    The vanishing of the form factor of the SU(3) single axial current is shown to be stable under the addition of derivative type symmetry breaking terms in the SU(3) Skyrme model. We find that treating the collective hamiltonian exactly dramatically lowers the predicted form factor for the strange quark axial current. Nevertheless, agreement with the EMC experiment is maintained. (orig.)

  16. Plasticity around an Axial Surface Crack in a Cylindrical Shell

    DEFF Research Database (Denmark)

    Krenk, Steen

    1979-01-01

    field in an axially cracked cylindrical shell arising from use of classical eighth order shallow shell theory is removed when use is made of a tenth order shell theory which accounts for transverse shear deformations. Although the membrane stresses are only moderately affected, the influence...... and Ratwani,3–5 it generalises Dugdale's assumption of a concentrated yield zone in the plane of the crack but, contrary to that model, transverse shear effects are included and a continuous stress distribution is assumed in the yield zone. The inherent difficulties arising from the use of shell theory...

  17. Nitinol stent design - understanding axial buckling.

    Science.gov (United States)

    McGrath, D J; O Brien, B; Bruzzi, M; McHugh, P E

    2014-12-01

    Nitinol׳s superelastic properties permit self-expanding stents to be crimped without plastic deformation, but its nonlinear properties can contribute towards stent buckling. This study investigates the axial buckling of a prototype tracheobronchial nitinol stent design during crimping, with the objective of eliminating buckling from the design. To capture the stent buckling mechanism a computational model of a radial force test is simulated, where small geometric defects are introduced to remove symmetry and allow buckling to occur. With the buckling mechanism ascertained, a sensitivity study is carried out to examine the effect that the transitional plateau region of the nitinol loading curve has on stent stability. Results of this analysis are then used to redesign the stent and remove buckling. It is found that the transitional plateau region can have a significant effect on the stability of a stent during crimping, and by reducing the amount of transitional material within the stent hinges during loading the stability of a nitinol stent can be increased. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Operating limits for subassembly deformation in EBR-II

    International Nuclear Information System (INIS)

    Bottcher, J.H.

    1977-01-01

    The deformation of a subassembly in response to the core environment is frequently the life limiting factor for that component in an LMFBR. Deformation can occur as diametral and axial growth or bowing of the subassembly. Such deformation has caused several handling problems in both the core and the storage basket of EBR-II and may also have contributed to reactivity anomalies during reactor operation. These problems generally affect plant availability but the reactivity anomalies could lead to a potential safety hazard. Because of these effects the deformation mechanisms must be understood and modeled. Diametral and axial growth of subassembly ducts in EBR-II is due to swelling and creep and is a function of temperature, neutron fluence and stress. The source of stress in a duct is the hydraulic pressure difference across the wall. By coupling the calculated subassembly growth rate to the available clearance in the core or storage basket a limiting neutron fluence, or exposure, can be established

  19. Axial magnetic field produced by axially and radially magnetized permanent rings

    International Nuclear Information System (INIS)

    Peng, Q.L.; McMurry, S.M.; Coey, J.M.D.

    2004-01-01

    Axial magnetic fields produced by axially and radially magnetized permanent magnet rings were studied. First, the axial magnetic field produced by a current loop is introduced, from which the axial field generated by an infinitely thin solenoid and by an infinitely thin current disk can be derived. Then the axial fields produced by axially and by radially magnetized permanent magnet rings can be obtained. An analytic formula for the axial fields produced by two axially magnetized rings is given. A permanent magnet with a high axial gradient field is fabricated, the measured results agree with the theoretical calculation very well. As an example, the axial periodic field produced by an arrangement of alternating axially and radially magnetized rings has been discussed

  20. View of the Axial Field Spectrometer

    CERN Multimedia

    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.

  1. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1994-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets, with a few more additions - with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers - exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the foree of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc. (orig.)

  2. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1993-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

  3. The met axial ligand determines the redox potential in Cu-A sites

    DEFF Research Database (Denmark)

    Ledesma, G.N.; Murgida, D.H.; Ly, H.K.

    2007-01-01

    The replacement of the axial methionine ligand in a native Cu-A protein rendered a series of stable mutants with spectroscopic features of a mixed valence center. The mutations resulted in minor perturbations of the electronic structure of this site but led to significant changes in the redox...... potential. This suggests that the axial ligand plays a role in tuning the redox potential Of Cu-A, resembling the behavior observed in blue copper sites....

  4. Crash worthy capacity of a hybridized epoxy-glass fiber aluminum columnar tube using repeated axial resistive force

    Energy Technology Data Exchange (ETDEWEB)

    Paruka, Perowansa [Jalan Politeknik, Kota Kinabalu (Malaysia); Siswanto, Waluyo Adi [Universiti Tun Hussein Onn Malaysia, Parit Raja (Malaysia); Maleque, Md Abdul [Universiti Islam Antarabangsa Malaysia, Kuala Lumpur (Malaysia); Shah, Mohd Kamal Mohd [Universiti Malaysia Sabah, Kota Kinabalu (Malaysia)

    2015-05-15

    A combination of aluminum columnar member with composite laminate to form a hybrid structure can be used as collapsible energy absorbers especially in automotive vehicular structures to protect occupants and cargo. A key advantage of aluminum member in composite is that it provides ductile and stable plastic collapse mechanisms with progressive deformation in a stable manner by increasing energy absorption during collision. This paper presents an experimental investigation on the influence of the number of hybrid epoxy glass layers in overwrap composite columnar tubes. Three columnar tube specimens were used and fabricated by hand lay-up method. Aluminum square hollow shape was combined with externally wrapped by using an isophthalic epoxy resin reinforced with glass fiber skin with an orientation angle of 0 .deg. /90 .deg. The aluminum columnar tube was used as reference material. Crushed hybrid-composite columnar tubes were prepared using one, two, and three layers to determine the crash worthy capacity. Quasi-static crush test was conducted using INSTRON machine with an axial loading. Results showed that crush force and the number of layers were related to the enhancement of energy absorption before the collapse of columnar tubes. The energy absorption properties of the crushed hybrid-composite columnar tubes improved significantly with the addition of layers in the overwrap. Microscopic analysis on the modes of epoxy-glass fiber laminate failure was conducted by using scanning electron microscopy.

  5. Axial loading screw fixation for chevron type osteotomies of the distal first metatarsal: a retrospective outcomes analysis.

    Science.gov (United States)

    Murphy, Ryan M; Fallat, Lawrence M; Kish, John P

    2014-01-01

    The distal chevron osteotomy is a widely accepted technique for the treatment of hallux abductovalgus deformity. Although the osteotomy is considered to be stable, displacements of the capital fragment has been described. We propose a new method for fixation of the osteotomy involving the axial loading screw (ALS) used in addition to single screw fixation. We believe this method will provide a more mechanically stable construct. We reviewed the charts of 46 patients in whom 52 feet underwent a distal chevron osteotomy that was fixated with either 1 screw or 2 screws that included the ALS. We hypothesized that the ALS group would have fewer displacements and would heal more quickly than the single screw fixation group. We found that the group with ALS fixation had healed at a mean of 6.5 weeks and that the group with single screw fixation had healed at 9.53 weeks (p = .001). Also, 8 cases occurred of displacement of the capital fragment in the single screw, control group compared with 2 cases of displacement in the ALS group. However, this finding was not statistically significant. The addition of the ALS to single screw fixation allowed the patients to heal approximately 3 weeks earlier than single screw fixation alone. The ALS is a fixation option for the surgeon to consider when osseous correction of hallux abducto valgus is performed. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Axial and Pressure Thrust Stiffness of Metal Bellows for Vibration Isolators

    Directory of Open Access Journals (Sweden)

    Ondřej Macháček

    2018-01-01

    Full Text Available Metal bellows are used as a spring element and simultaneously as a container (shell for a damping medium in vibration isolators, especially in applications where any leakage is inadmissible. Dynamic behaviour of these isolators is affected by axial stiffness of bellows and by a resistance against axial deformation of bellows filled with fluid, which is in this article called pressure thrust stiffness. A method of the pressure thrust stiffness determination is discussed in this study. The method uses FEM model, which has been verified by stiffness measurement of a chosen bellows. Consequently, the sensitivity analysis of bellows dimensions to axial and pressure thrust stiffness was performed to find a dimension parameter of bellows which allows to adjust the ratio between axial and pressure thrust stiffness. Sensitivity analysis shows that the stiffness ratio of metal bellows can be adjusted by two dimensional parameters - mean diameter of bellows and corrugation width.

  7. Axial Static Load Dependence Free Vibration Analysis of Helical Springs Based on the Theory of Spatially Curved Bars

    Directory of Open Access Journals (Sweden)

    Vebil Yildirim

    Full Text Available Abstract This work addresses an accurate and detailed axial static load dependence linearly elastic free vibration analysis of cylindrical helical springs based on the theory of spatially curved bars and the transfer matrix method. For a continuous system, governing equations comprise coupled vibration modes namely transverse vibrations in two orthogonal planes, torsional and axial vibrations. The axial and shear deformation effects together with the rotatory inertia effects are all considered based on the first order shear deformation theory and their effects on the frequencies are investigated. The effects of the initial stress resultants on the frequencies are also studied. After buckling, forward-shifting phenomenon of higher frequencies is noticeably demonstrated. It is also revealed that a free/forced vibration analysis with an axial static load should not be performed individually without checking buckling loads.

  8. Anisotropic deformation of Zr-2.5Nb pressure tube material at high temperatures

    Science.gov (United States)

    Fong, R. W. L.

    2013-09-01

    Zr-2.5Nb alloy is used for the pressure tubes in CANDU® reactor fuel channels. In reactor, the pressure tube normally operates at 300 °C and experiences a primary coolant fluid internal pressure of approximately 10 MPa. Manufacturing and processing procedures generate an anisotropic state in the pressure tube which makes the tube stronger in the hoop (transverse) direction than in the axial (longitudinal) direction. This anisotropy condition is present for temperatures less than 500 °C. During postulated accident conditions where the material temperature could reach 1000 °C, it might be assumed that the high temperature and subsequent phase change would reduce the inherent anisotropy, and thus affect the deformation behaviour (ballooning) of the pressure tube. From constant-load, rapid-temperature-ramp, uniaxial deformation tests, the deformation rate in the longitudinal direction of the tube behaves differently than the deformation rate in the transverse direction of the tube. This anisotropic mechanical behaviour appears to persist at temperatures up to 1000 °C. This paper presents the results of high-temperature deformation tests using longitudinal and transverse specimens taken from as-received Zr-2.5Nb pressure tubes. It is shown that the anisotropic deformation behaviour observed at high temperatures is largely due to the stable crystallographic texture of the α-Zr phase constituent in the material that was previously observed by neutron diffraction measurements during heating at temperatures up to 1050 °C. The deformation behaviour is also influenced by the phase transformation occurring at high temperatures during heating. The effects of texture and phase transformation on the anisotropic deformation of as-received Zr-2.5Nb pressure tube material are discussed in the context of the tube ballooning behaviour. Because of the high temperatures in postulated accident scenarios, any irradiation damage will be annealed from the pressure tube material and

  9. Texture and deformation mechanism of yttrium

    International Nuclear Information System (INIS)

    Adamesku, R.A.; Grebenkin, S.V.; Stepanenko, A.V.

    1992-01-01

    X-ray pole figure analysis was applied to study texture and deformation mechanism in pure and commercial polycrystalline yttrium on cold working. It was found that in cast yttrium the texture manifected itself weakly enough both for pure and commercial metal. Analysis of the data obtained made it possible to assert that cold deformation of pure yttrium in the initial stage occurred mainly by slip the role of which decreased at strains higher than 36%. The texture of heavily deformed commercial yttrium contained two components, these were an 'ideal' basic orientation and an axial one with the angle of inclination about 20 deg. Twinning mechanism was revealed to be also possible in commercial yttrium

  10. Seismic anisotropy in deforming salt bodies

    Science.gov (United States)

    Prasse, P.; Wookey, J. M.; Kendall, J. M.; Dutko, M.

    2017-12-01

    Salt is often involved in forming hydrocarbon traps. Studying salt dynamics and the deformation processes is important for the exploration industry. We have performed numerical texture simulations of single halite crystals deformed by simple shear and axial extension using the visco-plastic self consistent approach (VPSC). A methodology from subduction studies to estimate strain in a geodynamic simulation is applied to a complex high-resolution salt diapir model. The salt diapir deformation is modelled with the ELFEN software by our industrial partner Rockfield, which is based on a finite-element code. High strain areas at the bottom of the head-like strctures of the salt diapir show high amount of seismic anisotropy due to LPO development of halite crystals. The results demonstrate that a significant degree of seismic anisotropy can be generated, validating the view that this should be accounted for in the treatment of seismic data in, for example, salt diapir settings.

  11. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  12. Assessment of Axial Behavior of Circular HPFRCC Members Externally Confined with FRP Sheets

    Directory of Open Access Journals (Sweden)

    Ugur Demir

    2018-01-01

    Full Text Available The aim of this paper is to identify the axial behavior characteristics of FRP (fiber reinforced polymer confined circular HPFRCC (high performance fiber reinforced cementitious composite members under compression. The test program comprised of 24 circular specimens with an average compressive strength of 102.7 MPa, including 21 carbon FRP (CFRP confined (2, 4, 6, 8 and 10 layers and three unconfined specimens. Transverse confinement generated by external FRP sheets resulted with a remarkable enhancement in axial strength and deformability, which is extremely important to resist seismic actions. The higher was the thickness of FRP confinement, the larger was the ultimate strain (εcu and peak compressive strength (f′cc of externally confined HPFRCC. When compared to FRP confined conventional concrete, different axial and lateral deformation characteristics were seen in FRP jacketed HPFRCC members. Higher strength and steel fiber presence in HPFRCC limited the lateral deformations which resulted with reduced strain efficiency with respect to conventional concrete. After presenting the experimental work, performance and accuracy of several available models proposed for predicting the axial behavior of FRP jacketed concrete were evaluated in a comparative manner.

  13. Nonlinear analysis of shear deformable beam-columns partially ...

    African Journals Online (AJOL)

    user

    system of nonlinear equations from which the transverse and axial displacements are computed by an iterative process. The evaluation of the shear deformation ... doubly symmetric simply or multiply connected constant cross section, partially supported on tensionless Winkler foundation, undergoing moderate large ...

  14. Deformation and fatigue behaviors of carburized automotive gear steel and predictions

    Directory of Open Access Journals (Sweden)

    Bonglae Jo

    2016-07-01

    Full Text Available The fatigue behavior of carburized components such as automotive transmission gears is very complex due to hardness and microstructure difference, residual stresses and multi-axial stress states developed between the case and the core. In addition, automotive gears in service, commonly used in helical type, are actually subjected to complex stress conditions such as bending, torsion, and contact stress states. This study presents experimental and analytical results on deformation behavior of carburized steels, widely used in automotive gears, under cyclic stress conditions including axial and torsion loadings. Axial fatigue tests and rotating bending fatigue tests are also included. Predictions of cyclic deformation and fatigue behaviors of the carburized steel with two-layer model are compared with experimental results. The carburized steel investigated in this study exhibited cyclic softening under both axial loading and torsional loading. Predicted results with simple two-layer model for the cyclic deformation and fatigue behaviors were comparatively similar to the experimental data.

  15. Axial diagnostic package for Z

    International Nuclear Information System (INIS)

    Nash, T.J.; Derzon, M.S.; Chandler, G.

    1998-06-01

    The authors have developed and fielded an axial diagnostic package for the 20 MA, 100 ns, z-pinch driver Z. The package is used to diagnose dynamic hohlraum experiments which require an axial line of sight. The heart of the package is a reentrant cone originally used to diagnose ion-beam-driven hohlraums on PBFA-H. It has one diagnostic line of sight at 0 degrees, 4 at 6 degrees, and 4 at 9 degrees. In addition it has a number of viewing, alignment, and vacuum feedthrough ports. The front of the package sits approximately 5 feet from the pinch. This allows much closer proximity to the pinch, with inherently better resolution and signal, than is presently possible in viewing the pinch from the side. Debris that is preferentially directed along the axis is mitigated by two apertures for each line of sight, and by fast valves and imaging pinholes or cross slits for each diagnostic. In the initial run with this package they fielded a time resolved pinhole camera, a five-channel pinhole-apertured x-ray diode array, a bolometer, a spatially resolved time-integrated crystal spectrometer, and a spatially and temporally resolved crystal spectrometer. They present data obtained from these diagnostics in the dynamic hohlraum research conducted on Z

  16. Tuned dynamics stabilizes an idealized regenerative axial-torsional model of rotary drilling

    Science.gov (United States)

    Gupta, Sunit K.; Wahi, Pankaj

    2018-01-01

    We present an exact stability analysis of a dynamical system idealizing rotary drilling. This system comprises lumped parameter axial-torsional modes of the drill-string coupled via the cutting forces and torques. The kinematics of cutting is modeled through a functional description of the cut surface which evolves as per a partial differential equation (PDE). Linearization of this model is straightforward as opposed to the traditional state-dependent delay (SDDE) model and both the approaches result in the same characteristic equation. A systematic study on the key system parameters influencing the stability characteristics reveals that torsional damping is very critical and stable drilling is, in general, not possible in its absence. The stable regime increases as the natural frequency of the axial mode approaches that of the torsional mode and a 1:1 internal resonance leads to a significant improvement in the system stability. Hence, from a practical point of view, a drill-string with 1:1 internal resonance is desirable to avoid vibrations during rotary drilling. For the non-resonant case, axial damping reduces the stable range of operating parameters while for the resonant case, an optimum value of axial damping (equal to the torsional damping) results in the largest stable regime. Interestingly, the resonant (tuned) system has a significant parameter regime corresponding to stable operation even in the absence of damping.

  17. An Assessment of Cumulative Axial and Torsional Fatigue in a Cobalt-Base Superalloy

    Science.gov (United States)

    Kalluri, Sreeramesh; Bonacuse, Peter J.

    2010-01-01

    Cumulative fatigue under axial and torsional loading conditions can include both load-order (higMow and low/high) as well as load-type sequence (axial/torsional and torsional/axial) effects. Previously reported experimental studies on a cobalt-base superalloy, Haynes 188 at 538 C, addressed these effects. These studies characterized the cumulative axial and torsional fatigue behavior under high amplitude followed by low amplitude (Kalluri, S. and Bonacuse, P. J., "Cumulative Axial and Torsional Fatigue: An Investigation of Load-Type Sequance Effects," in Multiaxial Fatigue and Deformation: Testing and Prediction, ASTM STP 1387, S. Kalluri, and P. J. Bonacuse, Eds., American Society for Testing and Materials, West Conshohocken, PA, 2000, pp. 281-301) and low amplitude followed by high amplitude (Bonacuse, P. and Kalluri, S. "Sequenced Axial and Torsional Cumulative Fatigue: Low Amplitude Followed by High Amplitude Loading," Biaxial/Multiaxial Fatigue and Fracture, ESIS Publication 31, A. Carpinteri, M. De Freitas, and A. Spagnoli, Eds., Elsevier, New York, 2003, pp. 165-182) conditions. In both studies, experiments with the following four load-type sequences were performed: (a) axial/axial, (b) torsional/torsional, (c) axial/torsional, and (d) torsional/axial. In this paper, the cumulative axial and torsional fatigue data generated in the two previous studies are combined to generate a comprehensive cumulative fatigue database on both the load-order and load-type sequence effects. This comprehensive database is used to examine applicability of the Palmgren-langer-Miner linear damage rule and a nonlinear damage curve approach for Haynes 188 subjected to the load-order and load-type sequencing described above. Summations of life fractions from the experiments are compared to the predictions from both the linear and nonlinear cumulative fatigue damage approaches. The significance of load-order versus load-type sequence effects for axial and torsional loading conditions

  18. The internal vertebral venous plexus prevents compression of the dural sac during atlanto-axial rotation

    International Nuclear Information System (INIS)

    Reesink, E.M.; Lataster, L.M.A.; Mameren, H. van; Wilmink, J.T.; Kingma, H.

    2001-01-01

    Deformation of the extradural space and the possibility of impression upon the dural sac during atlanto-axial rotation are investigated. Atlanto-axial rotation leads to a reduction in the cross-sectional area of the bony spinal canal of approximately 40 %. Atlanto-axial rotation was recorded by endocanalar views from a video camera fixed inside the skull of six unembalmed cadavers. Axial thin-section T1-weighted MRI slice sets were acquired from three volunteers (mid-position and maximal left and right rotation of the head and cervical spine). The axial cross-sectional areas of the bony spinal canal, dural sac and spinal cord were measured. In two other persons post-gadolinium contrast-enhanced T1-weighted MRI volume scans with fat-suppression prepulse were acquired (mid-position and rotation) to determine venous contents of the extradural space. The 50:50 ratio between left and right extradural halves in mid-position changed to an ipsilateral:contralateral ratio of 20:80 in maximum rotation at the level just above the lateral C1-C2 joints. Directly below these joints the opposite occurred. The post-contrast studies showed an enhancing internal vertebral venous plexus (IVVP), which almost completely occupied the extradural space at the atlanto-axial level. This could not be shown in the cadaver experiments, because of absence of blood and cerebrospinal fluid (CSF) pressure. During atlanto-axial rotation blood displacement in the IVVP allows major deformations of the extradural space. This prevents dural sac impression. (orig.)

  19. Electric machines with axial magnetic flux

    Science.gov (United States)

    Nuca, I.; Ambros, T.; Burduniuc, M.; Deaconu, S. I.; Turcanu, A.

    2018-01-01

    The paper contains information on the performance of axial machines compared to cylindrical ones. At the same time, various constructive schemes of synchronous electromechanical converters with permanent magnets and asynchronous with short-circuited rotor are presented. In the developed constructions, the aim is to maximize the usage of the material of the stator windings. The design elements of the axial machine magnetic system are presented. The FEMM application depicted the array of the magnetic field of an axial machine.

  20. Axial vector mass spectrum and mixing angles

    International Nuclear Information System (INIS)

    Caffarelli, R.V.; Kang, K.

    1976-01-01

    Spectral sum rules of the axial-vector current and axial-vector current-pseudoscalar field are used to study the axial-vector mass spectrum and mixing angles, as well as the decay constants and mixing angles of the pseudoscalar mesons. In general, the result is quite persuasive for the existence of the Jsup(PC) = 1 ++ multiplet in which one has a canonical D-E mixing. (Auth.)

  1. Centrifugal and axial compressor control

    CERN Document Server

    McMillan, Gregory K

    2009-01-01

    Control engineers, mechanical engineers and mechanical technicians will learn how to select the proper control systems for axial and centrifugal compressors for proper throughput and surge control, with a particular emphasis on surge control. Readers will learn to understand the importance of transmitter speed, digital controller sample time, and control valve stroking time in helping to prevent surge. Engineers and technicians will find this book to be a highly valuable guide on compressor control schemes and the importance of mitigating costly and sometimes catastrophic surge problems. It can be used as a self-tutorial guide or in the classroom with the book's helpful end-of-chapter questions and exercises and sections for keeping notes.

  2. Axial channeling of uttrarelativistic electrons

    Energy Technology Data Exchange (ETDEWEB)

    Telegin, V.I.; Khokonov, M.Kh. (Moskovskij Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Yadernoj Fiziki)

    1982-07-01

    The dynamics of motion of ultrarelativistic electrons under axial channeling conditions is investigated. The analysis is based on the solution of the kinetic equation obtained recently by Beloshitsky and Kumakhov. The particle dechanneling function is investigated as depending on the type of a crystal, particle energy and angle of entrance into the single crystal. It is found that for most of the beam the major diffusion mechanism is scattering by electrons. It is shown that an optimal depth range exists for which the fraction of channeled particles sharply increases at the expense of the quasi-channeled particles. In a number of cases the dechanneling length for crystals with high atomic numbers may be greater than that of light elements.

  3. Axial channeling of uttrarelativistic electrons

    International Nuclear Information System (INIS)

    Telegin, V.I.; Khokonov, M.Kh.

    1982-01-01

    The dynamics of motion of ultrarelativistic electrons under axial channeling conditions is investigated. The analysis is based on the solution of the kinetic equation obtained recently by Beloshitsky and Kumakhov. The particle dechanneling function is investigated as depending on the type of a crystal, particle energy and angle of entrance into the single crystal. It is found that for most of the beam the major diffusion mechanism is scattering by electrons. It is shown that an optimal depth range exists for which the fraction of channeled particles sharply increases at the expense of the quasi-channeled particles. In a number of cases the dechanneling length for crystals with high atomic numbers may be greater than that of light elements

  4. Radial and axial compression of pure electron

    International Nuclear Information System (INIS)

    Park, Y.; Soga, Y.; Mihara, Y.; Takeda, M.; Kamada, K.

    2013-01-01

    Experimental studies are carried out on compression of the density distribution of a pure electron plasma confined in a Malmberg-Penning Trap in Kanazawa University. More than six times increase of the on-axis density is observed under application of an external rotating electric field that couples to low-order Trivelpiece-Gould modes. Axial compression of the density distribution with the axial length of a factor of two is achieved by controlling the confining potential at both ends of the plasma. Substantial increase of the axial kinetic energy is observed during the axial compression. (author)

  5. Axial and Radial Oxylipin Transport.

    Science.gov (United States)

    Gasperini, Debora; Chauvin, Adeline; Acosta, Ivan F; Kurenda, Andrzej; Stolz, Stéphanie; Chételat, Aurore; Wolfender, Jean-Luc; Farmer, Edward E

    2015-11-01

    Jasmonates are oxygenated lipids (oxylipins) that control defense gene expression in response to cell damage in plants. How mobile are these potent mediators within tissues? Exploiting a series of 13-lipoxygenase (13-lox) mutants in Arabidopsis (Arabidopsis thaliana) that displays impaired jasmonic acid (JA) synthesis in specific cell types and using JA-inducible reporters, we mapped the extent of the transport of endogenous jasmonates across the plant vegetative growth phase. In seedlings, we found that jasmonate (or JA precursors) could translocate axially from wounded shoots to unwounded roots in a LOX2-dependent manner. Grafting experiments with the wild type and JA-deficient mutants confirmed shoot-to-root oxylipin transport. Next, we used rosettes to investigate radial cell-to-cell transport of jasmonates. After finding that the LOX6 protein localized to xylem contact cells was not wound inducible, we used the lox234 triple mutant to genetically isolate LOX6 as the only JA precursor-producing LOX in the plant. When a leaf of this mutant was wounded, the JA reporter gene was expressed in distal leaves. Leaf sectioning showed that JA reporter expression extended from contact cells throughout the vascular bundle and into extravascular cells, revealing a radial movement of jasmonates. Our results add a crucial element to a growing picture of how the distal wound response is regulated in rosettes, showing that both axial (shoot-to-root) and radial (cell-to-cell) transport of oxylipins plays a major role in the wound response. The strategies developed herein provide unique tools with which to identify intercellular jasmonate transport routes. © 2015 American Society of Plant Biologists. All Rights Reserved.

  6. Taming axial dispersion in hydrodynamic chromatography columns through wall patterning

    Science.gov (United States)

    Adrover, Alessandra; Cerbelli, Stefano; Giona, Massimiliano

    2018-04-01

    A well-known limitation of hydrodynamic chromatography arises from the synergistic interaction between transverse diffusion and streamwise convection, which enhances axial dispersion through the Taylor-Aris mechanism. We show that a periodic sequence of slip/no-slip conditions at the channel walls (e.g., representing wall indentations hosting stable air pockets) can significantly reduce axial dispersion, thus enhancing separation performance. The theoretical/numerical analysis is based on a generalization of Brenner's macrotransport approach to solute transport, here modified to account for the finite-size of the suspended particles. The most effective dispersion-taming outcome is observed when the alternating sequence of slip/no-slip conditions yields non-vanishing cross-sectional flow components. The combination of these components with the hindering interaction between the channel boundaries and the finite-sized particles gives rise to a non-trivial solution of Brenner's problem on the unit periodic cell, where the cross-sectional particle number density departs from the spatially homogeneous condition. In turn, this effect impacts upon the solution of the so-called b-field defining the large-scale dispersion tensor, with an overall decremental effect on the axial dispersion coefficient and on the Height Equivalent of a Theoretical Plate.

  7. Axial range of conjugate adaptive optics in two-photon microscopy.

    Science.gov (United States)

    Paudel, Hari P; Taranto, John; Mertz, Jerome; Bifano, Thomas

    2015-08-10

    We describe an adaptive optics technique for two-photon microscopy in which the deformable mirror used for aberration compensation is positioned in a plane conjugate to the plane of the aberration. We demonstrate in a proof-of-principle experiment that this technique yields a large field of view advantage in comparison to standard pupil-conjugate adaptive optics. Further, we show that the extended field of view in conjugate AO is maintained over a relatively large axial translation of the deformable mirror with respect to the conjugate plane. We conclude with a discussion of limitations and prospects for the conjugate AO technique in two-photon biological microscopy.

  8. Formation Flying and Deformable Instruments

    International Nuclear Information System (INIS)

    Rio, Yvon

    2009-01-01

    Astronomers have always attempted to build very stable instruments. They fight all that can cause mechanical deformation or image motion. This has led to well established technologies (autoguide, active optics, thermal control, tip/tilt correction), as well as observing methods based on the use of controlled motion (scanning, micro scanning, shift and add, chopping and nodding). Formation flying disturbs this practice. It is neither possible to reduce the relative motion to very small amplitudes, nor to control it at will. Some impacts on Simbol-X instrument design, and operation are presented.

  9. Health and imaging outcomes in axial spondyloarthritis

    NARCIS (Netherlands)

    Machado, P.M.

    2016-01-01

    This thesis focuses on the assessment and monitoring of health and imaging outcomes in axial spondyloarthritis (SpA) and the relationship between these outcomes. Four major contributions to the understanding and management of axial SpA were made: 1) the improvement and facilitation of the assessment

  10. Aryabhata and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    GENERAL I ARTICLE. Aryabhata and Axial Rotation of Earth. 3. A Brief History. Amartya Kumar Datta is in the Stat-Math Unit of. Indian Statistic.llnstiutte,. Kolkata. His research ... historical account of some of Aryabha~a's views on axial rotation of Earth, ..... and stress on periodic observations and updating of the parameters.

  11. Transition in Deformation Mechanism of AZ31 Magnesium Alloy during High-Temperature Tensile Deformation

    Directory of Open Access Journals (Sweden)

    Masafumi Noda

    2011-01-01

    Full Text Available Magnesium alloys can be used for reducing the weight of various structural products, because of their high specific strength. They have attracted considerable attention as materials with a reduced environmental load, since they help to save both resources and energy. In order to use Mg alloys for manufacturing vehicles, it is important to investigate the deformation mechanism and transition point for optimizing the material and vehicle design. In this study, we investigated the transition of the deformation mechanism during the high-temperature uniaxial tensile deformation of the AZ31 Mg alloy. At a test temperature of 523 K and an initial strain rate of 3×10−3 s-1, the AZ31 Mg alloy (mean grain size: ~5 μm exhibited stable deformation behavior and the deformation mechanism changed to one dominated by grain boundary sliding.

  12. An exact dynamic stiffness matrix for axially loaded double-beam ...

    Indian Academy of Sciences (India)

    a Galerkin-type state-space approach for studying the transverse vibrations of double-beam sys- tems which was made of two ... First, the coupled governing equations of motion of the axially loaded double-beam system with shear deformation and .... and λ1 is a real root of the following cubic equation λ3 − a2λ2 + (a1a3 ...

  13. The effect of multi-axiality on damage with alternating stress

    International Nuclear Information System (INIS)

    Hug, J.; Zenner, H.; Schram, A.

    1992-01-01

    The aim of this project is a better understanding of the development of damage with multi-axial alternating stress. Hollow samples of the materials X6 CrNiTi 18 0 and Ck 15 are submitted to equal phase, phase displaced and consecutively alternating normal and thrust stresses. The amplitude ratio τ/σ is 1/2. Apart from the service life, the cyclic alternating deformation behaviour and the initiation and prapagation of microcracks are examined. (orig./MM) [de

  14. Axial anomalies of Lifshitz fermions

    CERN Document Server

    Bakas, Ioannis

    2011-01-01

    We compute the axial anomaly of a Lifshitz fermion theory with anisotropic scaling z=3 which is minimally coupled to geometry in 3+1 space-time dimensions. We find that the result is identical to the relativistic case using path integral methods. An independent verification is provided by showing with spectral methods that the eta-invariant of the Dirac and Lifshitz fermion operators in three dimensions are equal. Thus, by the integrated form of the anomaly, the index of the Dirac operator still accounts for the possible breakdown of chiral symmetry in non-relativistic theories of gravity. We apply this framework to the recently constructed gravitational instanton backgrounds of Horava-Lifshitz theory and find that the index is non-zero provided that the space-time foliation admits leaves with harmonic spinors. Using Hitchin's construction of harmonic spinors on Berger spheres, we obtain explicit results for the index of the fermion operator on all such gravitational instanton backgrounds with SU(2)xU(1) isom...

  15. Renormalization of the axial-vector current in QCD

    International Nuclear Information System (INIS)

    Chiu, C.B.; Pasupathy, J.; Wilson, S.L.

    1985-01-01

    Following the method of Ioffe and Smilga, the propagation of the baryon current in an external constant axial-vector field is considered. The close similarity of the operator-product expansion with and without an external field is shown to arise from the chiral invariance of gauge interactions in perturbation theory. Several sum rules corresponding to various invariants both for the nucleon and the hyperons are derived. The analysis of the sum rules is carried out by two independent methods, one called the ratio method and the other called the continuum method, paying special attention to the nondiagonal transitions induced by the external field between the ground state and excited states. Up to operators of dimension six, two new external-field-induced vacuum expectation values enter the calculations. Previous work determining these expectation values from PCAC (partial conservation of axial-vector current) are utilized. Our determination from the sum rules of the nucleon axial-vector renormalization constant G/sub A/, as well as the Cabibbo coupling constants in the SU 3 -symmetric limit (m/sub s/ = 0), is in reasonable accord with the experimental values. Uncertainties in the analysis are pointed out. The case of broken flavor SU 3 symmetry is also considered. While in the ratio method, the results are stable for variation of the fiducial interval of the Borel mass parameter over which the left-hand side and the right-hand side of the sum rules are matched, in the continuum method the results are less stable. Another set of sum rules determines the value of the linear combination 7F-5D to be roughly-equal0, or D/(F+D)roughly-equal(7/12). .AE

  16. Plasticity around an Axial Surface Crack in a Cylindrical Shell

    DEFF Research Database (Denmark)

    Krenk, Steen

    1979-01-01

    field in an axially cracked cylindrical shell arising from use of classical eighth order shallow shell theory is removed when use is made of a tenth order shell theory which accounts for transverse shear deformations. Although the membrane stresses are only moderately affected, the influence...... and Ratwani,3–5 it generalises Dugdale's assumption of a concentrated yield zone in the plane of the crack but, contrary to that model, transverse shear effects are included and a continuous stress distribution is assumed in the yield zone. The inherent difficulties arising from the use of shell theory...... of the yield zone. The model is used to analyse published test data on surface cracked pressurised pipes. The analysis consists in COD evaluation and estimate of failure as a consequence of plastic instability. A method is proposed which deals with the problem by simultaneous analysis of a number of cracks...

  17. Effects of pore fluid chemistry on stable sliding of Berea sandstone

    Science.gov (United States)

    Dunning, J. D.; Miller, M. E.

    1984-03-01

    Single-cycle and multiple-cycle frictional-sliding experiments were employed to evaluate the effects of pore fluid environments on yield strength, frictional-sliding dynamics, and gouge production and morphology. Circular right cylinders cored from Berea sandstone sawcut at 35° to the axes were saturated in water, an inorganic brine, and various anionic, cationic, and nonionic aqueous surface-active agents. Samples were deformed under an effective confining pressure of 50 MPa and an axial strain rate of 6×10-5 sec-1 until a 2% axial strain beyond yield (defined as the onset of sliding) was achieved. All samples were displaced by stable sliding. In the single-cycle tests the unsaturated and water-saturated samples displayed small stress peaks at yield. During stable sliding samples saturated with DTAB and SDS displayed slight increases in differential stress and statistically significant higher frictional coefficients than other environments (including water) but were very similar in behavior to dry, unsaturated samples. In the multiple-cycle tests, samples were loaded to 2% strain beyond yield and unloaded to a differential stress of approximately 5 10 MPa a total of four times. These results further suggest that DTAB exerts a ‘strengthening’ effect on the sandstone relative to water which, to a limiting value, increased with displacement. The DTAB and SDS environments also produced a coarser grain-size distribution in the gouge relative to gouge produced in the other environments. Investigation of the gouge by scanning electron microscope revealed that these larger ‘grains’ were composed of dense, apparently cemented aggregates of ultrafine, platy quartz particles.

  18. Introduction of axial chirality at a spiro carbon atom in the synthesis of pentaerythritol-imine macrocycles.

    Science.gov (United States)

    Grajewski, J; Piotrowska, K; Zgorzelak, M; Janiak, A; Biniek-Antosiak, K; Rychlewska, U; Gawronski, J

    2018-02-07

    Novel chiral macrocyclic polyimines with spiro carbon atoms are described. The key feature of the synthesis is the formation of an axially chiral quaternary carbon atom having four constitutionally identical substituents. This is possible either by the freezing of the labile conformation of a spiro-diboronate moiety or by the diastereomeric fitting of a conformationally stable spiro-acetal moiety into a chiral framework. A general model for the description of this type of axial chirality is proposed.

  19. Bone formation in axial spondyloarthritis.

    Science.gov (United States)

    Lories, Rik J; Haroon, Nigil

    2014-10-01

    The success of targeted therapies directed against tumor necrosis factor for patients with spondyloarthritis has shifted the focus of physicians and scientists towards the prevention of structural damage to the involved structures, in particular the sacroiliac joints and the spine, to avoid loss of function and disability. Structural damage to the skeleton as witnessed by radiography mainly consists of new bone formation potentially progressively leading to spine or joint ankylosis. This important long-term outcome parameter has been difficult to study, not alone because the time window for change may be long but also because human tissues with direct translational relevance are rarely available. Data from rodent models have identified growth factor signaling pathways as relevant targets. Both human and animal studies have tried to understand the link between inflammation and new bone formation. At the current moment, most evidence points towards a strong link between both but with the question still lingering about the sequence of events, disease triggers, and the interdependence of both features of disease. New discoveries such as a masterswitch T cell population that carries the IL23 receptor and the analysis of auto-antibodies directed again noggin and sclerostin are contributing to innovative insights into the pathophysiology of disease. Long-term data with tumor necrosis factor (TNF) inhibitors also suggest that some window of opportunity may exist to inhibit structural disease progression. All these data provide support for a further critical analysis of the available datasets and boost research in the field. The introduction of novel disease definitions, in particular the characterization of non-radiographic axial spondyloarthritis patients, will likely be instrumental in our further understanding of structural damage. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Shapeable sheet without plastic deformation

    Science.gov (United States)

    Oppenheimer, Naomi; Witten, Thomas A.

    2015-11-01

    Randomly crumpled sheets have shape memory. In order to understand the basis of this form of memory, we simulate triangular lattices of springs whose lengths are altered to create a topography with multiple potential energy minima. We then deform these lattices into different shapes and investigate their ability to retain the imposed shape when the energy is relaxed. The lattices are able to retain a range of curvatures. Under moderate forcing from a state of local equilibrium, the lattices deform by several percent but return to their retained shape when the forces are removed. By increasing the forcing until an irreversible motion occurs, we find that the transitions between remembered shapes show cooperativity among several springs. For fixed lattice structures, the shape memory tends to decrease as the lattice is enlarged; we propose ways to counter this decrease by modifying the lattice geometry. We survey the energy landscape by displacing individual nodes. An extensive fraction of these nodes proves to be bistable; they retain their displaced position when the energy is relaxed. Bending the lattice to a stable curved state alters the pattern of bistable nodes. We discuss this shapeability in the context of other forms of material memory and contrast it with the shapeability of plastic deformation. We outline the prospects for making real materials based on these principles.

  1. Faraday instability in deformable domains

    International Nuclear Information System (INIS)

    Pucci, G.

    2013-01-01

    Hydrodynamical instabilities are usually studied either in bounded regions or free to grow in space. In this article we review the experimental results of an intermediate situation, in which an instability develops in deformable domains. The Faraday instability, which consists in the formation of surface waves on a liquid experiencing a vertical forcing, is triggered in floating liquid lenses playing the role of deformable domains. Faraday waves deform the lenses from the initial circular shape and the mutual adaptation of instability patterns with the lens boundary is observed. Two archetypes of behaviour have been found. In the first archetype a stable elongated shape is reached, the wave vector being parallel to the direction of elongation. In the second archetype the waves exceed the response of the lens border and no equilibrium shape is reached. The lens stretches and eventually breaks into fragments that have a complex dynamics. The difference between the two archetypes is explained by the competition between the radiation pressure the waves exert on the lens border and its response due to surface tension.

  2. Diagnostic value of axial CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Kiuchi, Sousuke (Tsukuba Univ., Sakura, Ibaraki (Japan))

    1983-03-01

    Axial CT scan was used to investigate the radiological details of the temporal bone of 33 patients with chronic otitis media, secondary cholesteatoma, sensorineural hearing loss, Meniere disease, vertigo, facial spasm, and neoplasma. The axial scans showed anatomic details of the temporal bone, and at the same time clearly demonstrated the extent of the soft-tissue masses in the middle ears, as well as the destructions of the ossicles. Bone changes of the anterior walls of the epitympanum and external auditory meatus were more clearly demonstrated than by coronary CT scan. However, the axial scan had the disadvantages in demonstrating the stapes, crista transversa, and the mastoid portion of the facial canal.

  3. Axial force measurement for esophageal function testing

    DEFF Research Database (Denmark)

    Gravesen, Flemming Holbæk; Funch-Jensen, Peter; Gregersen, Hans

    2009-01-01

    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...... 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...

  4. Generalized dynamic model and control of ambiguous mono axial vehicle robot

    Directory of Open Access Journals (Sweden)

    Frantisek Duchon

    2016-09-01

    Full Text Available This article deals with the novel concept of ambiguous mono axial vehicle robot. Such robot is a combination of Segway and dicycle, which utilizes the advantages of each chassis. The advantage of dicycle is lower energy consumption during the movement and the higher safety of carried payload. The movable platform inside the ambiguous mono axial vehicle allows using the various sensors or devices. This will change the ambiguous mono axial vehicle to the Segway type robot. Both these modes are necessary to control in the stable mode to ensure the safety of the ambiguous mono axial vehicle’s movement. The main contents of the article contain description of generalized dynamic model of ambiguous mono axial vehicle and related control of ambiguous mono axial vehicle. The proposal is unique in that the same controller is used for both modes. Several simulations verify proposed control schemes and identified parameters. Moreover, the dicycle type of platform has never been used in robotics and that is another novelty.

  5. Canny edge-based deformable image registration.

    Science.gov (United States)

    Kearney, Vasant; Huang, Yihui; Mao, Weihua; Yuan, Baohong; Tang, Liping

    2017-02-07

    This work focuses on developing a 2D Canny edge-based deformable image registration (Canny DIR) algorithm to register in vivo white light images taken at various time points. This method uses a sparse interpolation deformation algorithm to sparsely register regions of the image with strong edge information. A stability criterion is enforced which removes regions of edges that do not deform in a smooth uniform manner. Using a synthetic mouse surface ground truth model, the accuracy of the Canny DIR algorithm was evaluated under axial rotation in the presence of deformation. The accuracy was also tested using fluorescent dye injections, which were then used for gamma analysis to establish a second ground truth. The results indicate that the Canny DIR algorithm performs better than rigid registration, intensity corrected Demons, and distinctive features for all evaluation matrices and ground truth scenarios. In conclusion Canny DIR performs well in the presence of the unique lighting and shading variations associated with white-light-based image registration.

  6. Growth-induced axial buckling of a slender elastic filament embedded in an isotropic elastic matrix

    KAUST Repository

    O'Keeffe, Stephen G.

    2013-11-01

    We investigate the problem of an axially loaded, isotropic, slender cylinder embedded in a soft, isotropic, outer elastic matrix. The cylinder undergoes uniform axial growth, whilst both the cylinder and the surrounding elastic matrix are confined between two rigid plates, so that this growth results in axial compression of the cylinder. We use two different modelling approaches to estimate the critical axial growth (that is, the amount of axial growth the cylinder is able to sustain before it buckles) and buckling wavelength of the cylinder. The first approach treats the filament and surrounding matrix as a single 3-dimensional elastic body undergoing large deformations, whilst the second approach treats the filament as a planar, elastic rod embedded in an infinite elastic foundation. By comparing the results of these two approaches, we obtain an estimate of the foundation modulus parameter, which characterises the strength of the foundation, in terms of the geometric and material properties of the system. © 2013 Elsevier Ltd. All rights reserved.

  7. Historical overview of spinal deformities in ancient Greece

    Directory of Open Access Journals (Sweden)

    Kaspiris Angelos

    2009-02-01

    Full Text Available Abstract Little is known about the history of spinal deformities in ancient Greece. The present study summarizes what we know today for diagnosis and management of spinal deformities in ancient Greece, mainly from the medical treatises of Hippocrates and Galen. Hippocrates, through accurate observation and logical reasoning was led to accurate conclusions firstly for the structure of the spine and secondly for its diseases. He introduced the terms kyphosis and scoliosis and wrote in depth about diagnosis and treatment of kyphosis and less about scoliosis. The innovation of the board, the application of axial traction and even the principle of trans-abdominal correction for correction of spinal deformities have their origin in Hippocrates. Galen, who lived nearly five centuries later impressively described scoliosis, lordosis and kyphosis, provided aetiologic implications and used the same principles with Hippocrates for their management, while his studies influenced medical practice on spinal deformities for more than 1500 years.

  8. Historical overview of spinal deformities in ancient Greece

    Science.gov (United States)

    Vasiliadis, Elias S; Grivas, Theodoros B; Kaspiris, Angelos

    2009-01-01

    Little is known about the history of spinal deformities in ancient Greece. The present study summarizes what we know today for diagnosis and management of spinal deformities in ancient Greece, mainly from the medical treatises of Hippocrates and Galen. Hippocrates, through accurate observation and logical reasoning was led to accurate conclusions firstly for the structure of the spine and secondly for its diseases. He introduced the terms kyphosis and scoliosis and wrote in depth about diagnosis and treatment of kyphosis and less about scoliosis. The innovation of the board, the application of axial traction and even the principle of trans-abdominal correction for correction of spinal deformities have their origin in Hippocrates. Galen, who lived nearly five centuries later impressively described scoliosis, lordosis and kyphosis, provided aetiologic implications and used the same principles with Hippocrates for their management, while his studies influenced medical practice on spinal deformities for more than 1500 years. PMID:19243609

  9. Effects of axial length and corneal curvature on corneal biomechanics in elderly population

    Directory of Open Access Journals (Sweden)

    Sha-Sha Song

    2018-02-01

    Full Text Available AIM:To explore the corneal biomechanical properties of the elderly with different axial length(ALand corneal curvature by corneal visualization Scheimpflug Technology(Corvis ST. METHODS: Cross-sectional study. A total of 161 patients(297 eyesundergoing phacoemulsification were collected in this study. They were divided into 22-24mm, 24-26mm, more than 26mm groups according to axial length(190 eyes, 54 eyes and 53 eyes, respectively. Those of whom axial length was 22-24mm and the corneal curvature was 42-44D were divided into male and female groups(44 eyes and 49 eyes, respectively. Those of whom axial length was 22-24mm were divided into 42-44D group, more than 44D group according to corneal curvature(88 eyes, 102 eyes, respectively. Corvis ST was used to measure the biomechanical parameters of the cornea. The differences in the parameters between different groups were analyzed using the independent-samples t test or one-way analysis of variance and correlation analyses were performed using Pearson correlation analysis. RESULTS: When comparing the corneal biomechanical parameters, no statistically significant differences were found between male and female groups(P>0.05. The first applanation length and second applanation length among different corneal curvatures were statistically significant(PPr=0.429, 0.278; Pr=-0.291, -0.415; PCONCLUSION: The corneal curvature and ocular axial length may be the factors affecting the corneal biomechanical characteristics. The longer axial length, the thinner corneal thickness, the more easily the corneal is deformed, and with the increase of the axial length, intraocular pressure also increases.

  10. Capacitive axial position and speed transduction system

    International Nuclear Information System (INIS)

    Jimenez D, H.; Flores Ll, H.; Cabral P, A.; Ramirez J, F.J.; Galindo, S.

    1984-01-01

    A new and inexpensive circuit arrangement of a capacitive axial position and speed transduction system is described. Design details and the theory of operation of the device are briefly outlined together with performance results. (author)

  11. Two pad axially grooved hydrostatic bearing

    Science.gov (United States)

    San Andres, Luis A. (Inventor)

    1995-01-01

    A hydrostatic bearing having two axial grooves on opposite sides of the bearing for breaking the rotational symmetry in the dynamic force coefficients thus reducing the whirl frequency ratio and increasing the damping and stiffness of the hydrostatic bearing.

  12. High temperature co-axial winding transformers

    Science.gov (United States)

    Divan, Deepakraj M.; Novotny, Donald W.

    1993-01-01

    The analysis and design of co-axial winding transformers is presented. The design equations are derived and the different design approaches are discussed. One of the most important features of co-axial winding transformers is the fact that the leakage inductance is well controlled and can be made low. This is not the case in conventional winding transformers. In addition, the power density of co-axial winding transformers is higher than conventional ones. Hence, using co-axial winding transformers in a certain converter topology improves the power density of the converter. The design methodology used in meeting the proposed specifications of the co-axial winding transformer specifications are presented and discussed. The final transformer design was constructed in the lab. Co-axial winding transformers proved to be a good choice for high power density and high frequency applications. They have a more predictable performance compared with conventional transformers. In addition, the leakage inductance of the transformer can be controlled easily to suit a specific application. For space applications, one major concern is the extraction of heat from power apparatus to prevent excessive heating and hence damaging of these units. Because of the vacuum environment, the only way to extract heat is by using a cold plate. One advantage of co-axial winding transformers is that the surface area available to extract heat from is very large compared to conventional transformers. This stems from the unique structure of the co-axial transformer where the whole core surface area is exposed and can be utilized for cooling effectively. This is a crucial issue here since most of the losses are core losses.

  13. Axial model in curved space-time

    Energy Technology Data Exchange (ETDEWEB)

    Barcelos-Neto, J.; Farina, C.; Vaidya, A.N.

    1986-12-11

    We study the axial model in a background gravitational field. Using the zeta-function regularization, we obtain explicitly the anomalous divergence of the axial-vector current and the exact generating functional of the theory. We show that, as a consequence of a space-time-dependent metric, all differential equations involved in the theory generalize to their covariantized forms. We also comment on the finite-mass renormalization exhibited by the pseudoscalar field and the form of the fermion propagator.

  14. Dechanneling function for relativistic axially channeled electrons

    International Nuclear Information System (INIS)

    Muralev, V.A.; Telegin, V.I.

    1981-01-01

    Behaviour of the x(t) dechanneling function depending on the depth is theoretically studied. Theoretical consideration of x(t) for axial channeled relativistic electrons in anisotropic medium results in two-dimensional kinetic equation with mixed derivatives of the parabolic type. The kinetic equation in the approximation of the continuous Lindchard model for relativistic axial channeled electrons is numerically solved. The depth dependence of the x(t) dechanneling function is obtained [ru

  15. Axial forces in centrifugal compressor couplings

    Science.gov (United States)

    Ivanov, A. N.; Ivanov, N. M.; Yun, V. K.

    2017-08-01

    The article presents the results of the theoretical and experimental investigation of axial forces arising in the toothed and plate couplings of centrifugal compressor shaft lines. Additional loads on the thrust bearing are considered that can develop in the toothed couplings as a result of coupled rotors misalignment. Design relationships to evaluate the level of axial forces and recommendations for their reduction in the operating conditions are given.

  16. High harmonic generation from axial chiral molecules.

    Science.gov (United States)

    Wang, Dian; Zhu, Xiaosong; Liu, Xi; Li, Liang; Zhang, Xiaofan; Lan, Pengfei; Lu, Peixiang

    2017-09-18

    Axial chiral molecules, whose stereogenic element is an axis rather than a chiral center, have attracted widespread interest due to their important application, such as asymmetric synthesis and chirality transfer. We investigate high harmonic generation from axial chiral molecules with bichromatic counterrotating circularly polarized laser fields. High harmonic generation from three typical molecules: (Sa)-3-chloropropa-1,2-dien-1-ol, propadiene, and (Ra)-2,3-pentadiene is simulated with time-dependent density-functional theory and strong field approximation. We found that harmonic spectra for 3D oriented axial chiral molecules exhibit obvious circular dichroism. However, the circular dichroism of High harmonic generation from an achiral molecule is much trivial. Moreover, the dichroism of high harmonic generation still exists when axial chiral molecules are 1D oriented,such as (Sa) -3-chloropropa-1,2-dien-1-ol. For a special form of axial chiral molecules with the formula abC=C=Cab (a, b are different substituents), like (Ra)-2,3-pentadiene, the dichroism discriminations disappear when the molecules are only in 1D orientation. The circular dichroism of high harmonic generation from axial chiral molecules is well explained by the trajectory analysis based on the semiclassical three-step mechanism.

  17. Deformations of superconformal theories

    International Nuclear Information System (INIS)

    Córdova, Clay; Dumitrescu, Thomas T.; Intriligator, Kenneth

    2016-01-01

    We classify possible supersymmetry-preserving relevant, marginal, and irrelevant deformations of unitary superconformal theories in d≥3 dimensions. Our method only relies on symmetries and unitarity. Hence, the results are model independent and do not require a Lagrangian description. Two unifying themes emerge: first, many theories admit deformations that reside in multiplets together with conserved currents. Such deformations can lead to modifications of the supersymmetry algebra by central and non-central charges. Second, many theories with a sufficient amount of supersymmetry do not admit relevant or marginal deformations, and some admit neither. The classification is complicated by the fact that short superconformal multiplets display a rich variety of sporadic phenomena, including supersymmetric deformations that reside in the middle of a multiplet. We illustrate our results with examples in diverse dimensions. In particular, we explain how the classification of irrelevant supersymmetric deformations can be used to derive known and new constraints on moduli-space effective actions.

  18. Adiabatically describing rare earths using microscopic deformations

    Science.gov (United States)

    Nobre, Gustavo; Dupuis, Marc; Herman, Michal; Brown, David

    2017-09-01

    Recent works showed that reactions on well-deformed nuclei in the rare-earth region are very well described by an adiabatic method. This assumes a spherical optical potential (OP) accounting for non-rotational degrees of freedom while the deformed configuration is described by couplings to states of the g.s. rotational band. This method has, apart from the global OP, only the deformation parameters as inputs, with no additional fit- ted variables. For this reason, it has only been applied to nuclei with well-measured deformations. With the new computational capabilities, microscopic large-scale calculations of deformation parameters within the HFB method based on the D1S Gogny force are available in the literature. We propose to use such microscopic deformations in our adi- abatic method, allowing us to reproduce the cross sections agreements observed in stable nuclei, and to reliably extend this description to nuclei far from stability, describing the whole rare-earth region. Since all cross sections, such as capture and charge exchange, strongly depend on the correct calculation of absorption from the incident channel (from direct reaction mechanisms), this approach significantly improves the accuracy of cross sections and transitions relevant to astrophysical studies. The work at BNL was sponsored by the Office of Nuclear Physics, Office of Science of the US Department of Energy, under Contract No. DE-AC02-98CH10886 with Brookhaven Science Associates, LLC.

  19. Relativistic quasiparticle random phase approximation in deformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pena Arteaga, D.

    2007-06-25

    Covariant density functional theory is used to study the influence of electromagnetic radiation on deformed superfluid nuclei. The relativistic Hartree-Bogolyubov equations and the resulting diagonalization problem of the quasiparticle random phase approximation are solved for axially symmetric systems in a fully self-consistent way by a newly developed parallel code. Three different kinds of high precision energy functionals are investigated and special care is taken for the decoupling of the Goldstone modes. This allows the microscopic investigation of Pygmy and scissor resonances in electric and magnetic dipole fields. Excellent agreement with recent experiments is found and new types of modes are predicted for deformed systems with large neutron excess. (orig.)

  20. Stable Isotope Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples (skin, bone, blood, muscle) are analyzed for stable carbon, stable nitrogen, and stable sulfur analysis. Many samples are used in their entirety for...

  1. Mechanics of deformable bodies

    CERN Document Server

    Sommerfeld, Arnold Johannes Wilhelm

    1950-01-01

    Mechanics of Deformable Bodies: Lectures on Theoretical Physics, Volume II covers topics on the mechanics of deformable bodies. The book discusses the kinematics, statics, and dynamics of deformable bodies; the vortex theory; as well as the theory of waves. The text also describes the flow with given boundaries. Supplementary notes on selected hydrodynamic problems and supplements to the theory of elasticity are provided. Physicists, mathematicians, and students taking related courses will find the book useful.

  2. Diffeomorphic Statistical Deformation Models

    DEFF Research Database (Denmark)

    Hansen, Michael Sass; Hansen, Mads/Fogtman; Larsen, Rasmus

    2007-01-01

    In this paper we present a new method for constructing diffeomorphic statistical deformation models in arbitrary dimensional images with a nonlinear generative model and a linear parameter space. Our deformation model is a modified version of the diffeomorphic model introduced by Cootes et al....... The modifications ensure that no boundary restriction has to be enforced on the parameter space to prevent folds or tears in the deformation field. For straightforward statistical analysis, principal component analysis and sparse methods, we assume that the parameters for a class of deformations lie on a linear...

  3. Deformed Open Quantum Systems

    Science.gov (United States)

    Isar, A.

    2004-09-01

    A master equation for the deformed quantum harmonic oscillator interacting with a dissipative environment, in particular with a thermal bath, is obtained in the microscopic model, using perturbation theory. The coefficients of the master equation depend on the deformation function. The steady state solution of the equation for the density matrix in the number representation is derived and the equilibrium energy of the deformed harmonic oscillator is calculated in the approximation of small deformation. Note from Publisher: This article contains the abstract and references only.

  4. Deformation compatibility control for engineering structures methods and applications

    CERN Document Server

    Zhu, Hanhua; Chen, Mengchong; Deng, Jianliang

    2017-01-01

    This book presents essential methods of deformation compatibility control, and explicitly addresses the implied conditions on the methods’ deformation compatibility. Consequently, these conditions can be considered in engineering structure design, while the conditions on stable equilibrium can be taken into account in the design method. Thus, the designed deformation and the actual deformation of the respective structure are approximately identical, guaranteeing both the flexibility of the construction material in force transmission and the equilibrium of force in the structure. Though equilibrium theory in engineering structures has been extensively studied, there has been comparatively little research on compatibility. In the limited researches available, the topics are primarily the theories and assumptions on the deformation compatibility, while few systematic works focus on the mechanical theoretical principles and methods of deformation compatibility control. As such, the flexibility of the constructi...

  5. High-resolution adaptive optics scanning laser ophthalmoscope with multiple deformable mirrors

    Science.gov (United States)

    Chen, Diana C.; Olivier, Scot S.; Jones; Steven M.

    2010-02-23

    An adaptive optics scanning laser ophthalmoscopes is introduced to produce non-invasive views of the human retina. The use of dual deformable mirrors improved the dynamic range for correction of the wavefront aberrations compared with the use of the MEMS mirror alone, and improved the quality of the wavefront correction compared with the use of the bimorph mirror alone. The large-stroke bimorph deformable mirror improved the capability for axial sectioning with the confocal imaging system by providing an easier way to move the focus axially through different layers of the retina.

  6. Intracrystalline deformation of calcite

    NARCIS (Netherlands)

    Bresser, J.H.P. de

    1991-01-01

    It is well established from observations on natural calcite tectonites that intracrystalline plastic mechanisms are important during the deformation of calcite rocks in nature. In this thesis, new data are presented on fundamental aspects of deformation behaviour of calcite under conditions where

  7. Vector and axial constants of the baryon decuplet

    International Nuclear Information System (INIS)

    Belyaev, V.M.; Blok, B.Y.; Kogan, Y.I.

    1985-01-01

    On the basis of the QCD sum rules for the polarization operator in external axial and vector fields we determine the vector and axial transition constants in the 3/2 + baryon decuplet. We show that the renormalization of the axial constant is due to the interaction of the external axial field with the quark condensate

  8. Nucleon axial form factor from lattice QCD

    International Nuclear Information System (INIS)

    Liu, K.F.; Dong, S.J.; Draper, T.; Wu, J.M.; Wilcox, W.

    1994-01-01

    Results for the isovector axial form factors of the proton from a lattice QCD calculation are presented for both the point-split and local currents. They are obtained on a quenched 16 3 x24 lattice at β=6.0 with Wilson fermions for a range of quark masses from strange to twice the charm mass. For each quark mass, we find that the axial form factor falls off slower than the corresponding proton electric form factor. Results extrapolated to the chiral limit show that the q 2 dependence of the axial form factor agrees quite well with experiment. The axial vector coupling constant g A calculated for the point-split and local currents is 1.20±0.11 and 1.18±0.11. The central values are 4% and 6% smaller than the experimental value of 1.254, respectively. We also consider the large ma correction and renormalization for the axial vector current of heavy quarks

  9. Deformation mechanisms in experimentally deformed Boom Clay

    Science.gov (United States)

    Desbois, Guillaume; Schuck, Bernhard; Urai, Janos

    2016-04-01

    Bulk mechanical and transport properties of reference claystones for deep disposal of radioactive waste have been investigated since many years but little is known about microscale deformation mechanisms because accessing the relevant microstructure in these soft, very fine-grained, low permeable and low porous materials remains difficult. Recent development of ion beam polishing methods to prepare high quality damage free surfaces for scanning electron microscope (SEM) is opening new fields of microstructural investigation in claystones towards a better understanding of the deformation behavior transitional between rocks and soils. We present results of Boom Clay deformed in a triaxial cell in a consolidated - undrained test at a confining pressure of 0.375 MPa (i.e. close to natural value), with σ1 perpendicular to the bedding. Experiments stopped at 20 % strain. As a first approximation, the plasticity of the sample can be described by a Mohr-Coulomb type failure envelope with a coefficient of cohesion C = 0.117 MPa and an internal friction angle ϕ = 18.7°. After deformation test, the bulk sample shows a shear zone at an angle of about 35° from the vertical with an offset of about 5 mm. We used the "Lamipeel" method that allows producing a permanent absolutely plane and large size etched micro relief-replica in order to localize and to document the shear zone at the scale of the deformed core. High-resolution imaging of microstructures was mostly done by using the BIB-SEM method on key-regions identified after the "Lamipeel" method. Detailed BIB-SEM investigations of shear zones show the following: the boundaries between the shear zone and the host rock are sharp, clay aggregates and clastic grains are strongly reoriented parallel to the shear direction, and the porosity is significantly reduced in the shear zone and the grain size is smaller in the shear zone than in the host rock but there is no evidence for broken grains. Comparison of microstructures

  10. Optimization of residual heat removal pump axial thrust and axial bearing

    International Nuclear Information System (INIS)

    Schubert, F.

    1996-01-01

    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

  11. 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.

  12. Strain reduced critical current in Bi-2223/Ag superconductors under axial tension and compression

    International Nuclear Information System (INIS)

    Haken, B. ten; Godeke, A.; Kate, H.H.J. ten

    1997-01-01

    The critical current of Ag sheathed Bi(Pb)SrCaCuO-2223 tape conductors is investigated as a function of various strain components. A reduction of the critical current occurs due to both tensile or a compressive strain. The critical current reduction is qualitatively similar with the results as observed in Bi-2212 conductors. An axial compression leads to an immediate critical current reduction. The critical current in an axially elongated sample remains nearly constant up to a certain limit typically close to 0.3% strain. For a larger elongation the critical current reduces rapidly. A transverse pressure acting on the tape surface leads also to an irreversible critical current reduction. This behavior is compared with the influence of an axial compression with an effective Young's modulus. The deformation induced critical current reductions in Bi-2223 conductors can be described by a model that is already proposed for Bi-2212 conductors. This model is based on the irreversible nature of the critical current reduction due to a certain deformation

  13. Axial-torsional fatigue - A study of tubular specimen thickness effects

    Science.gov (United States)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1993-01-01

    Experiments were carried out at room temperature on AISI type 316 stainless steel to determine the effect of wall thickness on the cyclic deformation behavior and fatigue life of thin-wall tubular axial-torsional fatigue specimens. The experimental variables examined included the depth of the surface work-hardened layer produced in specimen machining, and the effects of strain range and axial-torsional strain phasing. Tubular fatigue specimens had wall thicknesses of 1.5, 2.0, and 2.5 mm. One as-fabricated specimen from each wall thickness was sectioned for microstructural examination and microhardness measurement. A specimen of each wall thickness was tested in axial-torsional fatigue experiments for each of the three conditions: high strain range in-phase, low strain range in-phase, and low strain range out-of-phase. The machining-induced work-hardened zone, as a percentage of the gage section material, was found to have a minimal effect on both deformation behavior and fatigue life. Out-of-phase fatigue tests displayed shorter fatigue lives and more cyclic hardening than in-phase tests.

  14. An experimental study of physical property changes in crustal rocks undergoing triaxial deformation

    OpenAIRE

    Ayling, Mark Raymond

    1991-01-01

    A laboratory investigation has been undertaken to examine changes in a number of physical parameters of deforming brittle rocks. The experiments were carried out in a pressure-balanced. gas-medium triaxial cell. which is capable of simulating lower crustal conditions. During sample deformation. contemporaneous measurements were made of differential stress, axial strain, compressional wave velocity (Vp), shear wave velocity (Vs) and received elastic waveforms, which were stored for later...

  15. Wave propagation in axially moving periodic strings

    DEFF Research Database (Denmark)

    Sorokin, Vladislav S.; Thomsen, Jon Juel

    2017-01-01

    The paper deals with analytically studying transverse waves propagation in an axially moving string with periodically modulated cross section. The structure effectively models various relevant technological systems, e.g. belts, thread lines, band saws, etc., and, in particular, roller chain drives...... for diesel engines by capturing both their spatial periodicity and axial motion. The Method of Varying Amplitudes is employed in the analysis. It is shown that the compound wave traveling in the axially moving periodic string comprises many components with different frequencies and wavenumbers....... This is in contrast to non-moving periodic structures, for which all components of the corresponding compound wave feature the same frequency. Due to this "multi-frequency" character of the wave motion, the conventional notion of frequency band-gaps appears to be not applicable for the moving periodic strings. Thus...

  16. Stable convergence and stable limit theorems

    CERN Document Server

    Häusler, Erich

    2015-01-01

    The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

  17. Axial pico turbine - construction and experimental research

    Science.gov (United States)

    Peczkis, G.; Goryca, Z.; Korczak, A.

    2017-08-01

    The paper concerns axial water turbine of power equal to 1 kW. The example of axial water turbine constructional calculations was provided, as well as turbine rotor construction with NACA profile blades. The laboratory test rig designed and built to perform measurements on pico turbine was described. The turbine drove three-phase electrical generator. On the basis of highest efficiency parameters, pico turbine basic characteristics were elaborated. The experimental research results indicated that pico turbine can achieve maximum efficiency close to the values of larger water turbines.

  18. 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.

  19. Calcaneo-valgus deformity.

    Science.gov (United States)

    Evans, D

    1975-08-01

    A discussion of the essential deformity in calcaneo-valgus feet develops a theme originally put forward in 1961 on the relapsed club foot (Evans 1961). Whereas in the normal foot the medial and lateral columns are about equal in length, in talipes equino-varus the lateral column is longer and in calcaneo-valgus shorter than the medial column. The suggestion is that in the treatment of both deformities the length of the columns be made equal. A method is described of treating calcaneo-valgus deformity by inserting cortical bone grafts taken from the tibia to elongate the anterior end of the calcaneus.

  20. Adaptive fuzzy PID control of hydraulic servo control system for large axial flow compressor

    Science.gov (United States)

    Wang, Yannian; Wu, Peizhi; Liu, Chengtao

    2017-09-01

    To improve the stability of the large axial compressor, an efficient and special intelligent hydraulic servo control system is designed and implemented. The adaptive fuzzy PID control algorithm is used to control the position of the hydraulic servo cylinder steadily, which overcomes the drawback that the PID parameters should be adjusted based on the different applications. The simulation and the test results show that the system has a better dynamic property and a stable state performance.

  1. Two-dimensional analysis of axial segregation in batchwise and continuous Czochralski process

    Science.gov (United States)

    Hoe Wang, Jong; Hyun Kim, Do; Yoo, Hak-Do

    1999-03-01

    Transient two-dimensional convection-diffusion model has been developed to simulate the segregation phenomena in batchwise and continuous Czochralski process. Numerical simulations have been performed using the finite element method and implicit Euler time integration. The mesh deformation due to the change of the melt depth in batchwise Czochralski process was considered. Experimental values of the growth and system parameters for Czochralski growth of boron-doped, 4-in silicon single crystal were used in the numerical calculations. The experimental axial segregation in batchwise Czochralski process can be described successfully using convection-diffusion model. It has been demonstrated with this model that silicon single crystal with uniform axial dopant concentration can be grown and radial segregation can be suppressed in the continuous Czochralski process.

  2. LOAD CARRYING CAPABILITY OF LIQUID FILLED CYLINDRICAL SHELL STRUCTURES UNDER AXIAL COMPRESSION

    Directory of Open Access Journals (Sweden)

    QASIM H. SHAH

    2011-08-01

    Full Text Available Empty and water filled cylindrical Tin (Sn coated steel cans were loaded under axial compression at varying loading rates to study their resistance to withstand accidental loads. Compared to empty cans the water filled cans exhibit greater resistance to axially applied compression loads before a complete collapse. The time and load or stroke and load plots showed three significant load peaks related to three stages during loading until the cylinder collapse. First peak corresponds to the initial structural buckling of can. Second peak occurs when cylindrical can walls gradually come into full contact with water. The third peak shows the maximum load carrying capability of the structure where pressurized water deforms the can walls into curved shape until can walls fail under peak pressure. The collapse process of water filled cylindrical shell was further studied using Smooth Particle Hydrodynamics (SPH technique in LSDYNA. Load peaks observed in the experimental work were successfully simulated which substantiated the experimental work.

  3. Axial crystals macroscopic symmetry and tensor properties

    Czech Academy of Sciences Publication Activity Database

    Janovec, Václav

    2017-01-01

    Roč. 90, č. 1 (2017), s. 1-10 ISSN 0141-1594 Institutional support: RVO:68378271 Keywords : axial * polar * pseudopolar * chiral * enantiomorphism * optical activity Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.060, year: 2016

  4. Optimisation of efficiency of axial fans

    NARCIS (Netherlands)

    Kruyt, Nicolaas P.; Pennings, P.C.; Faasen, R.

    2014-01-01

    A three-stage research project has been executed to develop ducted axial-fans with increased efficiency. In the first stage a design method has been developed in which various conflicting design criteria can be incorporated. Based on this design method, an optimised design has been determined

  5. The design of axial shaftless pump

    Science.gov (United States)

    Schmirler, Michal; Netrebska, Hana

    The axial shaftless pump with a rotary casing has been proposed. The pump is unique in its small space requirements and the ability to draw a liquid with a high content of impurities and fibers. Modern motor with an external commutation was used to propel the pump rotor. The pump can be used for both pumping of liquids and marine propulsion.

  6. VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR

    African Journals Online (AJOL)

    Dr Obe

    1984-09-01

    Sep 1, 1984 ... VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR by. L. A. Agu. Electrical Engineering Department. University of Nigeria, Nsukka. ABSTRACT. This paper presents the scheme for a very slow speed linear machine which uses conventional laminations and with which speeds of the same low.

  7. Aryabha~ and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 4. Aryabhata and Axial Rotation of Earth - Naksatra Dina (the Sidereal Day). Amartya Kumar Dutta. General Article Volume 11 Issue 4 April 2006 pp 56-74. Fulltext. Click here to view fulltext PDF. Permanent link:

  8. Aryabhala and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 3. Aryabhata and Axial Rotation of Earth - Khagola (The Celestial Sphere). Amartya Kumar Dutta. General Article Volume 11 Issue 3 March 2006 pp 51-68. Fulltext. Click here to view fulltext PDF. Permanent link:

  9. The axial polarizability of nucleons and nuclei

    International Nuclear Information System (INIS)

    Ericson, M.; Figureau, A.

    1981-02-01

    The part of the static nuclear axial polarizability arising from the nucleonic excitations is derived from the low energy expansion of the πN amplitude. It is shown that the contribution of the Δ intermediate state, though dominant, does not saturate the nucleonic response. A similar effect, though more pronounced, is known to occur for the magnetic susceptibility

  10. Excitation modes in non-axial nuclei

    International Nuclear Information System (INIS)

    Leviatan, A.; Ginnochio, J.N.

    1990-01-01

    Excitation modes of non-axial quadrupole shapes are investigated in the framework of interacting boson models. Both γ-unstable and γ-rigid nuclear shapes are considered for systems with one type of boson as well as with proton-neutron bosons. 6 refs

  11. Excitation modes in non-axial nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A.; Ginnochio, J.N.

    1990-01-01

    Excitation modes of non-axial quadrupole shapes are investigated in the framework of interacting boson models. Both {gamma}-unstable and {gamma}-rigid nuclear shapes are considered for systems with one type of boson as well as with proton-neutron bosons. 6 refs.

  12. AERODYNAMIC DESIGN OF HIGH PRESSRE AXIAL FAN

    Directory of Open Access Journals (Sweden)

    Y. A. Ryzhov

    2014-01-01

    Full Text Available The paper presents the results of numerical studies of flow in a high axial fan of H-2, the geometric parameters are carefully designed by the author. The coefficients of performance, the total pressure, efficiency and capacity. Shows the benefits of fan of H-2 on several other fans, expressed in increased efficiency with equal dimensions and angles of blade setting.

  13. Co-axial, high energy gamma generator

    Science.gov (United States)

    Reijonen, Jani Petteri [Princeton, NJ; Gicquel, Frederic [Pennington, NJ

    2011-08-16

    A gamma ray generator includes an ion source in a first chamber. A second chamber is configured co-axially around the first chamber at a lower second pressure. Co-axially arranged plasma apertures separate the two chambers and provide for restricted passage of ions and gas from the first to the second chamber. The second chamber is formed by a puller electrode having at least one long channel aperture to draw ions from the first chamber when the puller electrode is subject to an appropriate applied potential. A plurality of electrodes rings in the third chamber in third pressure co-axially surround the puller electrode and have at least one channel corresponding to the at least one puller electrode aperture and plasma aperture. The electrode rings increase the energy of the ions to a selected energy in stages in passing between successive pairs of the electrodes by application of an accelerating voltage to the successive pairs of accelerator electrodes. A target disposed co-axially around the plurality of electrodes receives the beam of accelerated ions, producing gamma rays.

  14. Vibrations in deformed nuclei

    International Nuclear Information System (INIS)

    Aprahamian, A.

    1992-01-01

    Quadrupole oscillations around a deformed shape give rise to vibrations in deformed nuclei. Single phonon vibrations of K = 0 (β) and K = 2 (γ) are a systematic feature in deformed nuclei, but the existence of multi-phonon vibrations had remained an open question until the recently reported results in 168 Er. In this nucleus, a two-phonon K = 4(γγ) band was observed at approximately 2.5 times the energy of the single γ vibration. The authors have studied several deformed rare-earth nuclei using the ( 4 He,2n) reaction in order to map out the systematic behavior of these multi-phonon vibrations. Recently, they have identified a similar K = 4 band in 154 Gd

  15. The Spherical Deformation Model

    DEFF Research Database (Denmark)

    Hobolth, Asgar

    2003-01-01

    Miller et al. (1994) describe a model for representing spatial objects with no obvious landmarks. Each object is represented by a global translation and a normal deformation of a sphere. The normal deformation is defined via the orthonormal spherical-harmonic basis. In this paper we analyse the s...... a single central section of the object. We use maximum-likelihood-based inference for this purpose and demonstrate the suggested methods on real data....

  16. stableGP

    Data.gov (United States)

    National Aeronautics and Space Administration — The code in the stableGP package implements Gaussian process calculations using efficient and numerically stable algorithms. Description of the algorithms is in the...

  17. Permanent deformation testing for a new South African mechanistic pavement design method

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2012-01-01

    Full Text Available is to develop test protocols for hot-mix asphalt materials. To date, no permanent deformation test is incorporated into South African pavement design guides. The objective of this paper is to present the development process of a repeated load axial permanent...

  18. Crystalline cellulose elastic modulus predicted by atomistic models of uniform deformation and nanoscale indentation

    Science.gov (United States)

    Xiawa Wu; Robert J. Moon; Ashlie Martini

    2013-01-01

    The elastic modulus of cellulose Iß in the axial and transverse directions was obtained from atomistic simulations using both the standard uniform deformation approach and a complementary approach based on nanoscale indentation. This allowed comparisons between the methods and closer connectivity to experimental measurement techniques. A reactive...

  19. Properties of axially loaded implant-abutment assemblies using digital holographic interferometry analysis.

    Science.gov (United States)

    Brozović, Juraj; Demoli, Nazif; Farkaš, Nina; Sušić, Mato; Alar, Zeljko; Gabrić Pandurić, Dragana

    2014-03-01

    The aim of this study was to (i) obtain the force-related interferometric patterns of loaded dental implant-abutment assemblies differing in diameter and brand using digital holographic interferometry (DHI) and (ii) determine the influence of implant diameter on the extent of load-induced implant deformation by quantifying and comparing the obtained interferometric data. Experiments included five implant brands (Ankylos, Astra Tech, blueSKY, MIS and Straumann), each represented by a narrow and a wide diameter implant connected to a corresponding abutment. A quasi-Fourier setup with a 25mW helium-neon laser was used for interferometric measurements in the cervical 5mm of the implants. Holograms were recorded in two conditions per measurement: a 10N preloaded and a measuring-force loaded assembly, resulting with an interferogram. This procedure was repeated throughout the whole process of incremental axial loading, from 20N to 120N. Each measurement series was repeated three times for each assembly, with complete dismantling of the implant-loading device in between. Additional software analyses calculated deformation data. Deformations were presented as mean values±standard deviations. Statistical analysis was performed using linear mixed effects modeling in R's lme4 package. Implants exhibited linear deformation patterns. The wide diameter group had lower mean deformation values than the narrow diameter group. The diameter significantly affected the deformation throughout loading sessions. This study gained in vitro implant performance data, compared the deformations in implant bodies and numerically stated the biomechanical benefits of wider diameter implants. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  20. The Effects of Triggering Mechanisms on the Energy Absorption Capability of Circular Jute/Epoxy Composite Tubes under Quasi-Static Axial Loading

    Science.gov (United States)

    Sivagurunathan, Rubentheran; Lau Tze Way, Saijod; Sivagurunathan, Linkesvaran; Yaakob, Mohd. Yuhazri

    2018-01-01

    The usage of composite materials have been improving over the years due to its superior mechanical properties such as high tensile strength, high energy absorption capability, and corrosion resistance. In this present study, the energy absorption capability of circular jute/epoxy composite tubes were tested and evaluated. To induce the progressive crushing of the composite tubes, four different types of triggering mechanisms were used which were the non-trigger, single chamfered trigger, double chamfered trigger and tulip trigger. Quasi-static axial loading test was carried out to understand the deformation patterns and the load-displacement characteristics for each composite tube. Besides that, the influence of energy absorption, crush force efficiency, peak load, mean load and load-displacement history were examined and discussed. The primary results displayed a significant influence on the energy absorption capability provided that stable progressive crushing occurred mostly in the triggered tubes compared to the non-triggered tubes. Overall, the tulip trigger configuration attributed the highest energy absorption.

  1. Shell structure of octupole deformation

    International Nuclear Information System (INIS)

    Zhang Xizhen; Dong Baoguo

    1992-01-01

    A convenient definition of intrinsic frame of an octupole deformed shape was proposed recently. The octupole deformation potential was expanded on the bases of irreducible representations of group O h . Based on the parameterization given in previous paper, the shell structures of octupole deformation which cover all possible octupole deformed shapes were studied

  2. Exotic octupole deformation in proton-rich Z=N nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Takami, Satoshi; Yabana, K. [Niigata Univ. (Japan); Matsuo, M.

    1998-03-01

    We study static non-axial octupole deformations in proton-rich Z=N nuclei, {sup 64}Ge, {sup 68}Se, {sup 72}Kr, {sup 76}Sr, {sup 80}Zr and {sup 84}Mo, by using the Skyrme Hartree-Fock plus BCS method with no restrictions on the nuclear shape. The calculation predicts that the oblate ground state in {sup 68}Se is extremely soft for the Y{sub 33} triangular deformation, and that in {sup 80}Zr the low-lying local minimum state coexisting with the prolate ground state has the Y{sub 32} tetrahedral deformation. (author)

  3. Interaction domains in die-upset NdFeB magnets in dependence on the degree of deformation

    International Nuclear Information System (INIS)

    Khlopkov, K.; Gutfleisch, O.; Schaefer, R.; Hinz, D.; Mueller, K.-H.; Schultz, L.

    2004-01-01

    The magnetic domain structure of NdFeB magnets has been studied using high resolution, digitally enhanced Kerr-microscopy. Melt-spun NdFeB powder (MQU-F TM ) was hot pressed into fully dense samples and then hot deformed to axially textured magnets. Various degrees of deformation (height reduction) up to 76% have been realized. Pronounced interaction domains have been observed only in magnets, which were deformed to a degree of deformation of at least 52%. With increasing alignment of the grains the interaction domains become more and more visible and their size increases

  4. Electron states in quantum rings with structural distortions under axial or in-plane magnetic fields

    International Nuclear Information System (INIS)

    Planelles, J; Rajadell, F; Climente, J I

    2007-01-01

    A comprehensive study of anisotropic quantum rings, QRs, subject to axial and in-plane magnetic field, both aligned and transverse to the anisotropy direction, is carried out. Elliptical QRs for a wide range of eccentricity values and also perfectly circular QRs including one or more barriers disturbing the QR current are considered. These models mimic anisotropic geometry deformations and mass diffusion occurring in the QR fabrication process. Symmetry considerations and simplified analytical models supply physical insight into the obtained numerical results. Our study demonstrates that, except for unusual extremely large eccentricities, QR geometry deformations only appreciably influence a few low-lying states, while the effect of barriers disturbing the QR current is stronger and affects all studied states to a similar extent. We also show that the response of the electron states to in-plane magnetic fields provides accurate information on the structural anisotropy

  5. Deformable bag model of hadrons, 1

    Energy Technology Data Exchange (ETDEWEB)

    Ui, Haruo; Saito, Koich

    1983-05-01

    As a generalization of the MIT spherical bag model, we construct the spheroidal bag model of hadron with an arbitrary eccentricity. This generalization is made by slightly modifying the MIT linear boundary condition: The linear boundary condition is examined in detail. Our model always satisfies two necessary requirements of the MIT bag model - i.e., n.j = 0, no quark colour flux leaves the bag, and q-barq = 0, the scalar density of quark should vanish on the bag surface- and it reduces to the MIT spherical bag model in the limit of zero-eccentricity. Lagrangian formalism of our model is briefly described. The eigenfrequencies of a single massless quark confined in this spheroidal bag are numerically calculated. We obtain the level-splitting of the excited quark orbits, which is just analogous to the well-known Nilsson's splitting of single particle orbits in deformed nuclei. By using the numerical results of the lowest orbit, the effect of the bag-deformation on the mass of low-lying hadrons is estimated. It is found that, although the spherical bag is stable, the quark bag is extremely soft against the quadrupole deformation. Brief discussions are added on the mechanisms which make the spherical bag more stable.

  6. A deformable bag model of hadrons, 1

    International Nuclear Information System (INIS)

    Ui, Haruo; Saito, Koich

    1983-01-01

    As a generalization of the MIT spherical bag model, we construct the spheroidal bag model of hadron with an arbitrary eccentricity. This generalization is made by slightly modifying the MIT linear boundary condition: The linear boundary condition is examined in detail. Our model always satisfies two necessary requirements of the MIT bag model - i.e., n.j = 0, no quark colour flux leaves the bag, and q-barq = 0, the scalar density of quark should vanish on the bag surface- and it reduces to the MIT spherical bag model in the limit of zero-eccentricity. Lagrangian formalism of our model is briefly described. The eigenfrequencies of a single massless quark confined in this spheroidal bag are numerically calculated. We obtain the level-splitting of the excited quark orbits, which is just analogous to the well-known Nilsson's splitting of single particle orbits in deformed nuclei. By using the numerical results of the lowest orbit, the effect of the bag-deformation on the mass of low-lying hadrons is estimated. It is found that, although the spherical bag is stable, the quark bag is extremely soft against the quadrupole deformation. Brief discussions are added on the mechanisms which make the spherical bag more stable. (author)

  7. 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.

  8. Review of Axial Burnup Distribution Considerations for Burnup Credit Calculations

    International Nuclear Information System (INIS)

    Wagner, J.C.; DeHart, M.D.

    2000-01-01

    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

  9. Structure and properties of copper after large strain deformation

    Energy Technology Data Exchange (ETDEWEB)

    Rodak, Kinga; Molak, Rafal M.; Pakiela, Zbigniew

    2010-05-15

    Structure and properties of Cu in dependence on strain (from {epsilon}{proportional_to} 0.9 to {epsilon}{proportional_to} 15) during multi-axial compression processing at room temperature was investigated. The evolution of dislocation structure, misorientation distribution and crystallite size were observed by using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) equipment with electron back scattered diffraction (EBSD) facility. The mechanical properties of yield strength (YS), ultimate tensile strength (UTS) and uniform elongation was performed on MTS QTest/10 machine equipped with digital image correlation method (DIC). The structure-flow stress relationship of multi-axial compression processing material at strains {epsilon}{proportional_to} 3.5 and {epsilon}{proportional_to} 5.5 is discussed. It is found that processing does not produce any drastic changes in deformation structure and the microstructural refinement is slow. These results indicate that dynamic recrystallization plays an important role during multi-axial compression process in this range of deformation (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Piping inspection carriage having axially displaceable sensor

    Science.gov (United States)

    Zollinger, W.T.; Treanor, R.C.

    1994-12-06

    A pipe inspection instrument carriage is described for use with a pipe crawler for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has a Y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure. 4 figures.

  11. Ventajas de los motores de flujo axial

    Directory of Open Access Journals (Sweden)

    Alberto M Basanta Otero

    2011-03-01

    Full Text Available Es importante conocer sobre una familia de motores que a diferencia de los convencionales o tradicionales no presentanun flujo rotatorio radial, denominados motores de flujo axial. Dichos motores presentan altos valores de par motriz abajas velocidades, una alta eficiencia y alta densidad de potencia. Este trabajo constituye un breve análisis dealgunos motores de la referencia bibliográfica.  Is important to know about a family of motors that at difference whit the traditional, don't have a rotator radial flux,called, axial flux motors. These motors have high torque for low speed, high efficiency and high power density. Thiswork is a brief analysis of several motors of the bibliographic references.

  12. Cross-flow filtration and axial filtration

    International Nuclear Information System (INIS)

    Kraus, K.A.

    1974-01-01

    Two relatively novel alternative solid-liquid-separation techniques of filtration are discussed. In cross-flow filtration, the feed is pumped past the filtering surface. While in axial filtration the filter, mounted on a rotor, is moved with respect to the feed. While large-scale application of the axial filter is still in doubt, it permits with little expenditure of time and money, duplication of many hydrodynamic aspects of cross-flow filtration for fine-particle handling problems. The technique has been applied to municipal wastes, low-level radioactive waste treatment plant, lead removal from industrial wastes, removal of pulp-mill contaminants, textile-mill wastes, and pretreatment of saline waters by lime-soda process in preparation for hyperfiltration. Economics and energy requirements are also discussed

  13. Identification of Deformation Mechanisms During Bi-Axial Straining of Superplastic AA5083 Material

    National Research Council Canada - National Science Library

    Fowler, Rebecca M

    2004-01-01

    .... Orientation Imaging Microscopy was utilized to determine texture development, grain size and grain-to-grain misorientation angle distributions for locations located along a line of latitude of the dome samples...

  14. Axial Symmetric Solutions to Einstein's Field Equations for Deformed Neutron Stars

    Science.gov (United States)

    Zubairi, Omair; Weber, Fridolin

    2016-03-01

    Traditional models of neutron stars are constructed under of assumption that they are perfect spheres. This is not correct, however, if the matter inside of neutron stars is described by an non-isotropic model for the equation of state. Examples of such stars are magnetars and neutron stars that would contain color-superconducting quark matter. In this work, we derive the stellar structure equations which describe the properties of non-isotropic neutron stars. The equations are solved numerically in two dimensions. We calculate stellar properties such as masses and radii along with pressure and density profiles and investigate any changes from conventional spherically symmetric neutron stars. This work was supported through the National Science Foundation under Grants PHYS-1411708 and DUE-1259951. Additional computing resources were provided by the CSRC at SDSU and the Department of Sciences at Wentworth Institute of Technology.

  15. Axial pattern skin flaps in cats.

    Science.gov (United States)

    Remedios, A M; Bauer, M S; Bowen, C V; Fowler, J D

    1991-01-01

    The major direct cutaneous vessels identified in the cat include the omocervical, thoracodorsal, deep circumflex iliac, and caudal superficial epigastric arteries. Axial pattern skin flaps based on the thoracodorsal and caudal superficial epigastric arteries have been developed in cats. Rotation of these flaps as islands allows skin coverage to the carpus and metatarsus, respectively. The thoracodorsal and caudal superficial epigastric flaps provide a practical, one-step option in the reconstruction of large skin defects involving the distal extremities of cats.

  16. Atlanto-axial subluxation: a case report

    OpenAIRE

    Thurlow, Robert D

    1988-01-01

    One of the causes of death in rheumatoid patients is cord compression following atlanto-axial subluxation. Dislocations in the cervical spine are common with patients who have rheumatoid arthritis. Anterior subluxation occurs in up to 35%, followed by vertical subluxation in 22.2%, lateral subluxation in 20.6% and rarely posterior subluxation. A case report is presented to illustrate such a complication.

  17. Axial flux permanent magnet brushless machines

    CERN Document Server

    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

  18. Cervical Spine Axial Rotation Goniometer Design

    OpenAIRE

    Emin Ulaş Erdem; Filiz Can

    2012-01-01

    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, measureme...

  19. Autogenous Deformation of Concrete

    DEFF Research Database (Denmark)

    Autogenous deformation of concrete can be defined as the free deformation of sealed concrete at a constant temperature. A number of observed problems with early age cracking of high-performance concretes can be attributed to this phenomenon. During the last 10 years , this has led to an increased...... focus on autogenous deformation both within concrete practice and concrete research. Since 1996 the interest has been significant enough to hold international, yearly conferences entirely devoted to this subject. The papers in this publication were presented at two consecutive half-day sessions...... at the American Concrete Institute’s Fall Convention in Phoenix, Arizona, October 29, 2002. All papers have been reviewed according to ACI rules. This publication, as well as the sessions, was sponsored by ACI committee 236, Material Science of Concrete. The 12 presentations from 8 different countries indicate...

  20. Packings of deformable spheres

    Science.gov (United States)

    Mukhopadhyay, Shomeek; Peixinho, Jorge

    2011-07-01

    We present an experimental study of disordered packings of deformable spheres. Fluorescent hydrogel spheres immersed in water together with a tomography technique enabled the imaging of the three-dimensional arrangement. The mechanical behavior of single spheres subjected to compression is first examined. Then the properties of packings of a randomized collection of deformable spheres in a box with a moving lid are tested. The transition to a state where the packing withstands finite stresses before yielding is observed. Starting from random packed states, the power law dependence of the normal force versus packing fraction or strain at different velocities is quantified. Furthermore, a compression-decompression sequence at low velocities resulted in rearrangements of the spheres. At larger packing fractions, a saturation of the mean coordination number took place, indicating the deformation and faceting of the spheres.

  1. Axial gravity, massless fermions and trace anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Bonora, L. [International School for Advanced Studies (SISSA), Trieste (Italy); KEK, Tsukuba (Japan). KEK Theory Center; INFN, Sezione di Trieste (Italy); Cvitan, M.; Giaccari, S.; Stemberga, T. [Zagreb Univ. (Croatia). Dept. of Physics; Prester, P.D. [Rijeka Univ. (Croatia). Dept. of Physics; Pereira, A.D. [UERJ-Univ. Estadual do Rio de Janeiro (Brazil). Dept. de Fisica Teorica; UFF-Univ. Federal Fluminense, Niteroi (Brazil). Inst. de Fisica

    2017-08-15

    This article deals with two main topics. One is odd parity trace anomalies in Weyl fermion theories in a 4d curved background, the second is the introduction of axial gravity. The motivation for reconsidering the former is to clarify the theoretical background underlying the approach and complete the calculation of the anomaly. The reference is in particular to the difference between Weyl and massless Majorana fermions and to the possible contributions from tadpole and seagull terms in the Feynman diagram approach. A first, basic, result of this paper is that a more thorough treatment, taking account of such additional terms and using dimensional regularization, confirms the earlier result. The introduction of an axial symmetric tensor besides the usual gravitational metric is instrumental to a different derivation of the same result using Dirac fermions, which are coupled not only to the usual metric but also to the additional axial tensor. The action of Majorana and Weyl fermions can be obtained in two different limits of such a general configuration. The results obtained in this way confirm the previously obtained ones. (orig.)

  2. Axial polarizability and weak currents in nuclei

    International Nuclear Information System (INIS)

    Ericson, M.

    1977-01-01

    The weak interaction nucleonic coupling constants in nuclei are modified by the presence of the neighbouring nucleons. One type of modification is due to the virtual excitation of the isobars through meson exchange. The influence of the isobars is described by means of the nuclear axial polarizability coefficient. This polarizability is known; it is linked to the p-wave πN scattering volume. A relation is derived between the axial nuclear current and the pion field which incorporates the polarizability effects. This relation has an electromagnetic analogue. It is then possible to derive the axial and pseudoscalar coupling constants from a knowledge of the pion field. This field in turn obeys a Klein-Gordon equation which has to include the isobaric excitations. The propagation of the pion field is similar to that of an electromagnetic wave in a dielectric medium. The strong interaction coupling constant is shown to be renormalized in nuclei by the effect of the various types of correlations. (author)

  3. Respiratory effects of transient axial acceleration.

    Science.gov (United States)

    Loring, S H; Lee, H T; Butler, J P

    2001-06-01

    Whereas gravity has an inspiratory effect in upright subjects, transient upward acceleration is reported to have an expiratory effect. To explore the respiratory effects of transient axial accelerations, we measured axial acceleration at the head and transrespiratory pressure or airflow in five subjects as they were dropped or lifted on a platform. For the first 100 ms, upward acceleration caused a decrease in mouth pressure and inspiratory flow, and downward acceleration caused the opposite. We also simulated these experimental observations by using a computational model of a passive respiratory system based on anatomical data and normal respiratory characteristics. After 100 ms, respiratory airflow in our subjects became highly variable, no longer varying with acceleration. Electromyograms of thoracic and abdominal respiratory muscles showed bursts of activity beginning 40-125 ms after acceleration, suggesting reflex responses responsible for subsequent flow variability. We conclude that, in relaxed subjects, transient upward axial acceleration causes inspiratory airflow and downward acceleration causes expiratory airflow, but that after ~100 ms, reflex activation of respiratory musculature largely determines airflow.

  4. Atlanto-Axial Subluxation After Adenoidectomy.

    Science.gov (United States)

    Gross, Isabel Theresia; Bahar-Posey, Laleh

    2017-06-01

    Atlanto-axial subluxation is a rare but potentially serious complication after otolaryngological procedures. We are describing a case of a 4-year-old child who developed atlanto-axial subluxation of the cervical spine after adenoidectomy. Our patient underwent adenoidectomy and, 18 days later, presented to the emergency department with her neck tilted to the left in a cock-robin position and complaining of neck pain persisting since the surgery. A multiplanar 3-dimensional computed tomography was obtained and confirmed the diagnosis of an atlanto-axial subluxation (Fielding type 3). She was managed conservatively with the application of a cervical collar, anti-inflammatory medication, and manual reduction under anesthesia later in the course because of persistence of her symptoms. It is important to consider this diagnosis in any child who undergoes ENT surgical procedures complaining of neck pain subsequent to surgery or holding the head in a fixed position persistently after surgery. Early diagnosis is important to reduce the time between the onset of symptoms and reduction to reduce the risk or need for surgical intervention.

  5. Nanolaminate deformable mirrors

    Science.gov (United States)

    Papavasiliou, Alexandros P.; Olivier, Scot S.

    2009-04-14

    A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.

  6. Measurement of Local Deformations in Steel Monostrands Using Digital Image Correlation

    DEFF Research Database (Denmark)

    Winkler, Jan; Fischer, Gregor; Georgakis, Christos T.

    2014-01-01

    , difficulties with the placement of strain gauges in the vicinity of the anchorage, and, most importantly, the relatively small magnitude of deformation occurring in the monostrand. This paper focuses on the measurement of localized deformations in high-strength steel monostrands using the digital image......The local deformation mechanisms in steel monostrands have a significant influence on their fatigue life and failure mode. However, the observation and quantification of deformations in monostrands experiencing axial and transverse deformations is challenging because of their complex geometry....... To validate the proposed image-based measurement method, two different tests were performed, with the one correlation method showing good agreement. Data collected from the DIC technique creates a basis for the analysis of the fretting and localized bending behavior of the monostrand and provides relevant...

  7. The deep structure of Axial Volcano

    Science.gov (United States)

    West, Michael Edwin

    The subsurface structure of Axial Volcano, near the intersection of the Juan de Fuca Ridge and the Cobb-Eickelberg seamount chain in the northeast Pacific, is imaged from an active source seismic experiment. At a depth of 2.25 to 3.5 km beneath Axial lies an 8 km x 12 km region of very low seismic velocities that can only be explained by the presence of magma. In the center of this magma storage chamber at 2--3.5 km below sea floor, the crust is at least 10--20% melt. At depths of 4--5 km there is evidence of additional low concentrations of magma (a few percent) over a larger area. In total, 5--11 km3 of magma are stored in the mid-crust beneath Axial. This is more melt than has been positively identified under any basaltic volcano on Earth. It is also far more than the 0.1--0.2 km3 emplaced during the 1998 eruption. The implied residence time in the magma reservoir of a few hundred to a few thousand years agrees with geochemical trends which suggest prolonged storage and mixing of magmas. The large volume of melt bolsters previous observations that Axial provides much of the material to create crust along its 50 km rift zones. A high velocity ring-shaped feature sits above the magma chamber just outside the caldera walls. This feature is believed to be the result of repeated dike injections from the magma body to the surface during the construction of the volcanic edifice. A rapid change in crustal thickness from 8 to 11 km within 15 km of the caldera implies focused delivery of melt from the mantle. The high flux of magma suggests that melting occurs deeper in the mantle than along the nearby ridge. Melt supply to the volcano is not connected to any plumbing system associated with the adjacent segments of the Juan de Fuca Ridge. This suggests that, despite Axial's proximity to the ridge, the Cobb hot spot currently drives the supply of melt to the volcano.

  8. A subspace thermodynamic model for shape memory alloy wire elements undergoing combined thermo-mechanical axial and torsional loads

    Science.gov (United States)

    Sumanth, D.; Preetish, K. L.; Srinivasan, S. M.

    2014-08-01

    Given that most applications of shape memory alloys (SMA) are in the wire form, a reduced order model and analysis has been attempted in this paper. It takes into account the fact that the predominant actions are axial (bending inclusive) and torsional. A thermodynamic framework is first developed to simulate the behaviour of the SMA material under thermo-mechanical loading that is a combination of axial and shear stresses arising at a point in a wire due to axial and torsional loads applied to the wire. Since only a few variants relevant to axial-torsion are going to be active in transformation under this kind of loading, a reduced order model that tracks the evolution of four martensite variants and an austenite variant is proposed. It is shown through simulations that these five model parameters amply form a minimal set of model parameters sufficient for simulating response under tension-torsion loading excursions. The model is further applied to the structural member, in this case, a wire of circular cross-section subject to a twist and an axial extension and the capability of the model to simulate the kind of response expected in wires. Incorporation of this model into a large deformation space frame nonlinear analysis will help in the design and analysis of several applications where SMA wire forms are used.

  9. A subspace thermodynamic model for shape memory alloy wire elements undergoing combined thermo-mechanical axial and torsional loads

    International Nuclear Information System (INIS)

    Sumanth, D; Preetish, K L; Srinivasan, S M

    2014-01-01

    Given that most applications of shape memory alloys (SMA) are in the wire form, a reduced order model and analysis has been attempted in this paper. It takes into account the fact that the predominant actions are axial (bending inclusive) and torsional. A thermodynamic framework is first developed to simulate the behaviour of the SMA material under thermo-mechanical loading that is a combination of axial and shear stresses arising at a point in a wire due to axial and torsional loads applied to the wire. Since only a few variants relevant to axial-torsion are going to be active in transformation under this kind of loading, a reduced order model that tracks the evolution of four martensite variants and an austenite variant is proposed. It is shown through simulations that these five model parameters amply form a minimal set of model parameters sufficient for simulating response under tension–torsion loading excursions. The model is further applied to the structural member, in this case, a wire of circular cross-section subject to a twist and an axial extension and the capability of the model to simulate the kind of response expected in wires. Incorporation of this model into a large deformation space frame nonlinear analysis will help in the design and analysis of several applications where SMA wire forms are used. (paper)

  10. Development an efficient calibrated nonlocal plate model for nonlinear axial instability of zirconia nanosheets using molecular dynamics simulation.

    Science.gov (United States)

    Sahmani, S; Fattahi, A M

    2017-08-01

    New ceramic materials containing nanoscaled crystalline phases create a main object of scientific interest due to their attractive advantages such as biocompatibility. Zirconia as a transparent glass ceramic is one of the most useful binary oxides in a wide range of applications. In the present study, a new size-dependent plate model is constructed to predict the nonlinear axial instability characteristics of zirconia nanosheets under axial compressive load. To accomplish this end, the nonlocal continuum elasticity of Eringen is incorporated to a refined exponential shear deformation plate theory. A perturbation-based solving process is put to use to derive explicit expressions for nonlocal equilibrium paths of axial-loaded nanosheets. After that, some molecular dynamics (MD) simulations are performed for axial instability response of square zirconia nanosheets with different side lengths, the results of which are matched with those of the developed nonlocal plate model to capture the proper value of nonlocal parameter. It is demonstrated that the calibrated nonlocal plate model with nonlocal parameter equal to 0.37nm has a very good capability to predict the axial instability characteristics of zirconia nanosheets, the accuracy of which is comparable with that of MD simulation. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Light and heavy touch reduces postural sway and modifies axial tone in Parkinson's disease.

    Science.gov (United States)

    Franzén, Erika; Paquette, Caroline; Gurfinkel, Victor; Horak, Fay

    2012-10-01

    Light touch with a stable object reduces postural sway by increasing axial postural tone in healthy subjects. However, it is unknown whether subjects with Parkinson's disease (PD), who have more postural sway and higher axial postural tone than healthy subjects, can benefit from haptic touch. To investigate the effect of light and heavy touch on postural stability and hip tone in subjects with PD. Fourteen subjects with mid-stage PD and 14 healthy control subjects were evaluated during quiet standing with eyes closed with their arms (a) crossed, (b) lightly touching a fixed rigid bar in front of them, and (c) firmly gripping the bar. Postural sway was measured with a forceplate, and axial hip tone was quantified using a unique device that measures the resistance of the hips to yaw rotation while maintaining active stance. Subjects with PD significantly decreased their postural sway with light or heavy touch (P touch, hip tone was larger in PD subjects. With touch, however, tone values were similar in both groups. This change in hip tone with touch was highly correlated with the initial amount of tone (PD, r = -.72 to -.95; controls, r = -.74 to -.85). The authors showed, for the first time, that subjects with PD benefit from touch similarly to control subjects and that despite higher axial postural tone, PD subjects are able to modulate their tone with touch. Future studies should investigate the complex relationship between touch and postural tone.

  12. The impact of deformable interfaces and Poiseuille flow on the thermocapillary instability of three immiscible phases confined in a channel

    DEFF Research Database (Denmark)

    Javier Alvarez, Nicolas; Uguz, A. Kerem

    2013-01-01

    -examines the Marangoni-Bénard instability for a three-layer system with deformable interfaces undergoing Poiseuille flow. Taking into account the deformability of the interface reveals new physics. Linear stability analysis shows that at small wave numbers a deformable interface is of the orders of magnitude less...... stable than a non-deformable interface. At large wave numbers, both a rigid and a deformable interface have the same stability. Furthermore, a base planar Poiseuille flow affects the linear stability of the system and the type of instability when the interface is allowed to deform. Flow stabilizes...

  13. Octupole Deformed Nuclei in the Actinide Region

    CERN Multimedia

    Thorsteinsen, T; Rubio barroso, B; Simpson, J; Gulda, K; Sanchez-vega, M; Cocks, J; Nybo, K; Garcia borge, M; Aas, A; Fogelberg, B; Honsi, J; Smith, G; Naumann, R; Grant, I

    2002-01-01

    The aim of the present study is to investigate the limits of the "island" of octupole deformation in the mass region A=225. It is of particular importance to demonstrate experimentally the sudden disappearance of the stable octupole deformation in the presence of a well developed quadrupole field. \\\\ \\\\In order to establish the upper border line the $\\beta$ -decay chains of $^{227}$Rn $\\rightarrow ^{227}$Fr $\\rightarrow ^{227}$Ra and $^{231}$Fr $\\rightarrow ^{231}$Ra $\\rightarrow ^{231}$Ac were studied at PSB-ISOLDE using advanced fast timing and $\\gamma$-ray spectroscopy techniques. The lifetimes of the excited states have been measured in the picosecond range using the time-delayed $\\beta\\gamma\\gamma$(t) method.

  14. Intrinsic carpal ligaments on MR and multidetector CT arthrography: comparison of axial and axial oblique planes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ryan K.L.; Griffith, James F.; Ng, Alex W.H.; Law, Eric K.C. [The Chinese University of Hong Kong, Department of Imaging and Interventional Radiology, Prince Of Wales Hospital, Hong Kong (China); Tse, W.L.; Wong, Clara W.Y.; Ho, P.C. [The Chinese University of Hong Kong, Department of Orthopedics and Traumatology, Prince Of Wales Hospital, Hong Kong (China)

    2017-03-15

    To compare axial and oblique axial planes on MR arthrography (MRA) and multidetector CT arthrography (CTA) to evaluate dorsal and volar parts of scapholunate (SLIL) and lunotriquetral interosseous (LTIL) ligaments. Nine cadaveric wrists of five male subjects were studied. The visibility of dorsal and volar parts of the SLIL and LTIL was graded semi-quantitatively (good, intermediate, poor) on MRA and CTA. The presence of a ligament tear was determined on arthrosocopy and sensitivity, specificity and accuracy of tear detection were calculated. Oblique axial imaging was particularly useful for delineating dorsal and volar parts of the LTIL on MRA with overall 'good' visibility increased from 11 % to 78 %. The accuracy of MRA and CTA in revealing SLIL and LTIL tear was higher using the oblique axial plane. The overall accuracy for detecting SLIL tear on CTA improved from 94 % to 100 % and from 89 % to 94 % on MRA; the overall accuracy of detecting LTIL tear on CTA improved from 89 % to 100 % and from 72 % to 89 % on MRA Oblique axial imaging during CT and MR arthrography improves detection of tears in the dorsal and volar parts of both SLIL and LTIL. (orig.)

  15. Marginally Deformed Starobinsky Gravity

    DEFF Research Database (Denmark)

    Codello, A.; Joergensen, J.; Sannino, Francesco

    2015-01-01

    We show that quantum-induced marginal deformations of the Starobinsky gravitational action of the form $R^{2(1 -\\alpha)}$, with $R$ the Ricci scalar and $\\alpha$ a positive parameter, smaller than one half, can account for the recent experimental observations by BICEP2 of primordial tensor modes....

  16. Swept source optical coherence tomography Gabor fusion splicing technique for microscopy of thick samples using a deformable mirror.

    Science.gov (United States)

    Costa, Christopher; Bradu, Adrian; Rogers, John; Phelan, Pauline; Podoleanu, Adrian

    2015-01-01

    We present a swept source optical coherence tomography (OCT) system at 1060 nm equipped with a wavefront sensor at 830 nm and a deformable mirror in a closed-loop adaptive optics (AO) system. Due to the AO correction, the confocal profile of the interface optics becomes narrower than the OCT axial range, restricting the part of the B-scan (cross section) with good contrast. By actuating on the deformable mirror, the depth of the focus is changed and the system is used to demonstrate Gabor filtering in order to produce B-scan OCT images with enhanced sensitivity throughout the axial range from a Drosophila larvae. The focus adjustment is achieved by manipulating the curvature of the deformable mirror between two user-defined limits. Particularities of controlling the focus for Gabor filtering using the deformable mirror are presented.

  17. Calculation of rotational deformity in pediatric supracondylar humerus fractures

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Eric R.; Egol, Kenneth A.; Bosse, Harold J.P. van; Schweitzer, Mark E.; Pettrone, Sarah K. [NYU Hospital for Joint Diseases, New York, NY (United States); Feldman, David S. [NYU Hospital for Joint Diseases, New York, NY (United States); NYU Hospital for Joint Diseases, Pediatric Orthopaedic Surgery, Center for Children, New York, NY (United States)

    2007-03-15

    Supracondylar humerus fractures (SCHF) are common in the pediatric population. Cubitus varus deformity (CVD) is the most common long-term complication of SCHFs and may lead to elbow instability and deficits in throwing or extension. Distal fragment malrotation in the axial plane disposes to fragment tilt and CVD; however, no simple method of assessing fracture malrotation exists. This study tested a mathematical method of measuring axial plane malrotation in SCHFs based on plain radiographs. A pediatric SCHF model was made, and x-rays were taken at known intervals of rotation. Five independent, blinded observers measured these films. Calculated rotation for each data set was compared to the known rotation. The identical protocol was performed for an aluminum phantom. The reliability and agreement of the rotation values were good for both models. This method is a reliable, accurate, and cost-effective means of calculating SCHF distal fragment malrotation and warrants clinical application. (orig.)

  18. Axial flow heat exchanger devices and methods for heat transfer using axial flow devices

    Science.gov (United States)

    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.

  19. Numerical study on air-structure coupling dynamic characteristics of the axial fan blade

    Science.gov (United States)

    Chen, Q. G.; Xie, B.; Li, F.; Gu, W. G.

    2013-12-01

    In order to understand the dynamic characteristics of the axial-flow fan blade due to the effect of rotating stress and the action of unsteady aerodynamic forces caused by the airflow, a numerical simulation method for air-structure coupling in an axial-flow fan with fixed rear guide blades was performed. The dynamic characteristics of an axial-flow fan rotating blade were studied by using the two-way air-structure coupling method. Based on the standard k-ε turbulence model, and using weak coupling method, the preceding six orders modal parameters of the rotating blade were obtained, and the distributions of stress and strain on the rotating blade were presented. The results show that the modal frequency from the first to the sixth order is 3Hz higher than the modal frequency without considering air-structure coupling interaction; the maximum stress and the maximum strain are all occurred in the vicinity of root area of the blade no matter the air-structure coupling is considered or not, thus, the blade root is the dangerous location subjected to fatigue break; the position of maximum deformation is at the blade tip, so the vibration of the blade tip is significant. This study can provide theoretical references for the further study on the strength analysis and mechanical optimal design.

  20. Formation and subdivision of deformation structures during plastic deformation

    DEFF Research Database (Denmark)

    Jakobsen, B.; Poulsen, H.F.; Lienert, U.

    2006-01-01

    of individual, deeply embedded dislocation structures. During tensile deformation of pure copper, dislocation-free regions were identified. They showed an unexpected intermittent dynamics, for example, appearing and disappearing with proceeding deformation and even displaying transient splitting behavior....... Insight into these processes is relevant for an understanding of the strength and work-hardening of deformed materials....

  1. Stable isotopes labelled compounds

    International Nuclear Information System (INIS)

    1982-09-01

    The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

  2. Stable Boundary Layer Issues

    NARCIS (Netherlands)

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

  3. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    IAS Admin

    After Maynard-Smith and Price [1] mathematically derived why a given behaviour or strategy was adopted by a certain proportion of the population at a given time, it was shown that a strategy which is currently stable in a population need not be stable in evolutionary time (across generations). Additionally it was sug-.

  4. Large inelastic deformation analysis of steel pressure vessels at high temperature

    International Nuclear Information System (INIS)

    Ikonen, K.

    2001-01-01

    This publication describes the calculation methodology developed for a large inelastic deformation analysis of pressure vessels at high temperature. Continuum mechanical formulation related to a large deformation analysis is presented. Application of the constitutive equations is simplified when the evolution of stress and deformation state of an infinitesimal material element is considered in the directions of principal strains determined by the deformation during a finite time increment. A quantitative modelling of time dependent inelastic deformation is applied for reactor pressure vessel steels. Experimental data of uniaxial tensile, relaxation and creep tests performed at different laboratories for reactor pressure vessel steels are investigated and processed. An inelastic deformation rate model of strain hardening type is adopted. The model simulates well the axial tensile, relaxation and creep tests from room temperature to high temperature with only a few fitting parameters. The measurement data refined for the inelastic deformation rate model show useful information about inelastic deformation phenomena of reactor pressure vessel steels over a wide temperature range. The methodology and calculation process are validated by comparing the calculated results with measurements from experiments on small scale pressure vessels. A reasonably good agreement, when taking several uncertainties into account, is obtained between the measured and calculated results concerning deformation rate and failure location. (orig.)

  5. Exploring the Hydrolytic Behavior of the Platinum(IV) Complexes with Axial Acetato Ligands.

    Science.gov (United States)

    Zhao, Jian; Xu, Zichen; Lin, Jing; Gou, Shaohua

    2017-08-21

    Platinum(IV) complexes are generally thought to be kinetically inert, and are expected to be stable enough to resist premature aquation before entering the cancer cells. Nevertheless, in this work, complex 2 with axial acetato ligands can hydrolyze relatively quickly under biologically relevant conditions with a half-life of 91.7 min, resulting in the loss of the equatorial chlorido ligand. Further study indicated that the fast hydrolysis of complex 2 may be attributed to the strong σ-donor ability of N-isopropyl-1R,2R-diaminocyclohexane, and an increasing σ-donor ability of the amine group can promote the hydrolysis rate of the corresponding platinum(IV) complex. The experiment results were proven by the corresponding DFT calculation. Our study can help to re-evaluate the aqueous properties of the platinum(IV) complexes with axial acetate, which may be less inert to hydrolysis than expected under biologically relevant conditions.

  6. Postural deformities in Parkinson's disease

    NARCIS (Netherlands)

    Doherty, K.M.; Warrenburg, B.P.C. van de; Peralta, M.C.; Silveira-Moriyama, L.; Azulay, J.P.; Gershanik, O.S.; Bloem, B.R.

    2011-01-01

    Postural deformities are frequent and disabling complications of Parkinson's disease (PD) and atypical parkinsonism. These deformities include camptocormia, antecollis, Pisa syndrome, and scoliosis. Recognition of specific postural syndromes might have differential diagnostic value in patients

  7. QCD plasma parameters in axial gauge

    Energy Technology Data Exchange (ETDEWEB)

    Nachbagauer, H. (Technische Univ., Vienna (Austria). Inst. fuer Theoretische Physik)

    1992-11-01

    Within the framework of imaginary time formalism we investigate the structure of the gluon polarization tensor and relate its structure functions to the dispersion relation of plasma eigenmodes. To one loop order, we calculate the transversal structure function to leading order in the high temperature expansion as well as the first subleading order contribution in the long wavelength limit. The result is used to express the dynamical mass and the damping constant for transversal plasma eigenmodes. The aim of our present paper is a systematic discussion of the gauge fixing vector dependence of the damping constant. In the limit of temporal axial gauge we encounter a negative damping constant contradicting previous results. (orig.).

  8. QCD plasma parameters in axial gauge

    Science.gov (United States)

    Nachbagauer, Herbert

    1992-09-01

    Within the framework of imaginary time formalism we investigate the structure of the gluon polarization tensor and relate its structure functions to the dispersion relation of plasma eigenmodes. To one loop order, we calculate the transversal structure function to leading order in the high temperature expansion as well as the first subleading order contribution in the long wavelength limit. The result is used to express the dynamical mass and the damping constant for transversal plasma eigenmodes. The aim of our present paper is a systematic discussion of the gauge fixing vector dependence of the damping constant. In the limit of temporal axial gauge we encounter a negative damping constant contradicting previous results.

  9. Disordered axial movement in Parkinson's disease.

    OpenAIRE

    Steiger, M J; Thompson, P D; Marsden, C D

    1996-01-01

    Axial motor impairments are a common cause of disability in patients with Parkinson's disease, become more prominent with longer disease duration, and have been said to be less responsive to levodopa replacement therapy. The ability to turn in bed while lying supine before and after dopaminergic stimulation was studied in a group of 36 patients with Parkinson's disease; 23 were in Hoehn and Yahr stages 3-5 when "off", and 13 were in stages 1-2. Turning was also compared with postural stabilit...

  10. Water ingestion into jet engine axial compressors

    Science.gov (United States)

    Tsuchiya, T.; Murthy, S. N. B.

    1982-01-01

    An axial flow compressor has been tested with water droplet ingestion under a variety of conditions. The results illustrate the manner in which the compressor pressure ratio, efficiency and surging characteristics are affected. A model for estimating the performance of a compressor during water ingestion has been developed and the predictions obtained compare favorably with the test results. It is then shown that with respect to five droplet-associated nonlinearly-interacting processes (namely, droplet-blade interactions, blade performance changes, centrifugal action, heat and mass transfer processes and droplet break-up), the initial water content and centrifugal action play the most dominant roles.

  11. Ankylosing Spondylitis versus Nonradiographic Axial Spondyloarthritis

    DEFF Research Database (Denmark)

    Glintborg, Bente; Sørensen, Inge J; Østergaard, Mikkel

    2017-01-01

    OBJECTIVE: To compare baseline disease activity and treatment effectiveness in biologic-naive patients with nonradiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS) who initiate tumor necrosis factor inhibitor (TNFi) treatment and to study the role of potential confounders....../disease duration/TNFi-type/smoking/baseline disease activity) on TNFi adherence and response [e.g., Bath Ankylosing Spondylitis Activity Index (BASDAI) 50%/20 mm]. RESULTS: The study included 1250 TNFi-naive patients with axSpA (29% nr-axSpA, 50% AS, 21% lacked radiographs of sacroiliac joints). Patients...

  12. 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.

  13. Stable classification of the energy-momentum tensor. Summary

    International Nuclear Information System (INIS)

    Guzman-Sanchez, A.R.; Przanowski, M.; Plevansky, J.

    1990-01-01

    Starting with the algebraic classification of the energy-momentum tensor given by Plebansky, it is established that this classification is unstable under versal deformations and a new (stable) classification is given. In order to keep the text to reasonable length, we just write the basic ideas and some results. (Author) (Author)

  14. Cosmetic and Functional Nasal Deformities

    Science.gov (United States)

    ... nasal complaints. Nasal deformity can be categorized as “cosmetic” or “functional.” Cosmetic deformity of the nose results in a less ... taste , nose bleeds and/or recurrent sinusitis . A cosmetic or functional nasal deformity may occur secondary to ...

  15. q-Deformed Kink solutions

    International Nuclear Information System (INIS)

    Lima, A.F. de

    2003-01-01

    The q-deformed kink of the λφ 4 -model is obtained via the normalisable ground state eigenfunction of a fluctuation operator associated with the q-deformed hyperbolic functions. The kink mass, the bosonic zero-mode and the q-deformed potential in 1+1 dimensions are found. (author)

  16. Pattern of seismic deformation in the Western Mediterranean

    Directory of Open Access Journals (Sweden)

    S. Pondrelli

    1999-06-01

    Full Text Available The seismic deformation of the Western Mediterranean was studied with the aim of defining the strain pattern that characterizes the Africa-Eurasia plate boundary in this area. Within different sections along the boundary the cumulative moment tensor was computed over 90 years of seismological data. The results were compared with NUVELlA plate motion model and geodetic data. A stable agreement was found along Northern Africa to Sicily, where only Africa and Eurasia plates are involved. In this zone it is evident that changes in the strike of the boundary correspond to variations in the prevailing geometry of deformation, tectonic features and in the percentage of seismic with respect to total expected deformation. The geometry of deformation of periadriatic sections (Central to Southern Apennines, Eastern Alps and the Eastern Adriatic area agrees well with VLBI measurements and with regional geological features. Seismicity seems to account for low rates, from 3% to 31%, of total expected deformation. Only in the Sicily Strait, characterized by extensional to strike slip deformation, does the ratio reach a higher value (79%. If the amount of deformation deduced from seismicity seems low, because 90 years are probably not representative of the recurrence seismic cycle of the Western Mediterranean, the strain pattern we obtain from cumulative moment tensors is more representative of the kinematics of this area than global plate motion models and better identifies lower scale geodynamic features.

  17. Lenke 1C and 5C spinal deformities fused selectively: 5-year outcomes of the uninstrumented compensatory curves.

    Science.gov (United States)

    Ilgenfritz, Ryan M; Yaszay, Burt; Bastrom, Tracey P; Newton, Peter O

    2013-04-15

    Multicenter review of prospectively collected data. To analyze the natural history of uninstrumented compensatory curves prospectively during a 5-year postoperative period in patients with selectively fused Lenke type 1C and 5C adolescent idiopathic scoliosis. After a selective fusion for 1C and 5C adolescent idiopathic scoliosis curve types, there is concern that uninstrumented compensatory curves will continue to progress over time. However, to date, there have been no studies using prospectively collected data beyond 2 years to determine the natural history of these uninstrumented compensatory curves. Lenke 1C and 5C adolescent idiopathic scoliosis cases, prospectively collected from a multicenter study were analyzed. All patients underwent a selective fusion (1C only thoracic curve fused; 5C only thoracolumbar/lumbar curve fused). Preoperative, first-erect, 1-year, 2-year, and 5-year postoperative coronal, sagittal, and axial (Perdriolle) radiographical outcomes were compared using repeated measures analysis of variance with Bonferroni post hoc comparisons (P 5C curves were reviewed. Preoperative compensatory curve Cobb angles were 40° ± 6° and 25° ± 9°, respectively. In Lenke 1C curves, the uninstrumented compensatory lumbar curves were corrected by 32% ± 16% at first erect, 44% ± 17% correction at 1 year, 38% ± 15% correction at 2 years, and 39% ± 19% at 5 years. In Lenke 5C curves, the uninstrumented compensatory thoracic curves were corrected by a mean of 37% ± 29% at first erect, 42% ± 29% at 1 year, 37% ± 29% at 2 years, and 30% ± 23% at 5 years. The sagittal and axial measures of the compensatory curves remained stable during the postoperative period. In Lenke 1C and 5C adolescent idiopathic scoliosis deformity patterns fused selectively, the uninstrumented compensatory curves adjust to match the instrumented primary curve and do not seem to progress between 1 and 5 years postoperatively.

  18. Conservative management of extra-axial hematomas diagnosed by CT

    International Nuclear Information System (INIS)

    Muszynski, C.A.; Hayman, L.A.; Weingarten, K.; Prow, H.W.; Cole, J.W.; Contant, C.F.

    1999-01-01

    Our purpose was to assess the role of serial CT in recently traumatized patients with clinically stable extra-axial intracranial hematomas (EACH) and a midline shift of less than 0.5 cm. A retrospective review of 91 imaging studies in 41 patients (with 45 EACH) was done to assess the time between trauma and CT; the presence and type of skull fracture; the volume, type, and location of the EACH; the presence of associated edema and/or contusion. Over a 19-day follow-up, 11 % of the dense EACH increased in volume and 27 % decreased. An adjacent skull fracture was seen most frequently in patients with a decrease in EACH volume. Clinical data remain the key to determining the need for neurosurgical intervention in patients with EACH. Follow-up CT afforded no data which altered the medical management of these patients. However, it may be said to have alerted the clinician to an increase in the size of the EACH in 11 % of cases, which could mandate close observation of this group. (orig.)

  19. Comminuted supracondylar femoral fractures: a biomechanical analysis comparing the stability of medial versus lateral plating in axial loading

    Directory of Open Access Journals (Sweden)

    Nikolai Briffa

    2016-10-01

    Full Text Available Abstract The aim of this study was to compare the biomechanical properties of medial and lateral plating of a medially comminuted supracondylar femoral fracture. A supracondylar femoral fracture model comparing two fixation methods was tested cyclically in axial loading. One-centimetre supracondylar gap osteotomies were created in six synthetic femurs approximately 6 cm proximal to the knee joint. There were two constructs investigated: group 1 and group 2 were stabilized with an 8-hole LC-DCP, medially and laterally, respectively. Both construct groups were axially loaded. Global displacement (total length, wedge displacement, bending moment and strain were measured. Medial plating showed a significantly decreased displacement, bending moment and strain at the fracture site in axial loading. Medial plating of a comminuted supracondylar femur fracture is more stable than lateral plating.

  20. [Babies with cranial deformity].

    Science.gov (United States)

    Feijen, Michelle M W; Claessens, Edith A W M Habets; Dovens, Anke J Leenders; Vles, Johannes S; van der Hulst, Rene R W J

    2009-01-01

    Plagiocephaly was diagnosed in a baby aged 4 months and brachycephaly in a baby aged 5 months. Positional or deformational plagio- or brachycephaly is characterized by changes in shape and symmetry of the cranial vault. Treatment options are conservative and may include physiotherapy and helmet therapy. During the last two decades the incidence of positional plagiocephaly has increased in the Netherlands. This increase is due to the recommendation that babies be laid on their backs in order to reduce the risk of sudden infant death syndrome. We suggest the following: in cases of positional preference of the infant, referral to a physiotherapist is indicated. In cases of unacceptable deformity of the cranium at the age 5 months, moulding helmet therapy is a possible treatment option.

  1. Medullary sponge kidney on axial computed tomography

    International Nuclear Information System (INIS)

    Ginalski, J.-M.; Schnyder, Pierre; Portmann, Luc; Jaeger, Philippe

    1991-01-01

    To evaluate features of medullary sponge kidney (MSK) on computed tomography (CT), 4-mm-thick axial slices without intravenous contrast material were 1st made in 13 patients through 24 kidneys which showed images of MSK on excretory urograms. On CT, papillary calcifications were found in 11 kidneys. In 5 of these, the calcifications were not detectable on plain films. Some hyperdense papillae (attenuation value 55-70 Hounsfield units) without calcification were found in 4 other kidneys. 9 kidneys appeared normal. 10 of the 14 kidneys were reexamined by a 2nd series of 4-mm-thick axial slices, 5 min after intravenous injection of 50 ml of Urografin. Images suggesting possible ectasia of precaliceal tubules were found in only 4 kidneys. These images appear much less obvious and characteristic on CT than on excretory urogram and do nothing more than suggest the possibility of MSK. In conclusion, the sensitivity of CT in the detection of MSK is markedly lower than that of excretory urography. In the most florid cases of the disease, CT can only show images suggesting the possibility of MSK. On the other hand, CT appears much more sensitive than plain films and tomograms of excretory in the detection of papillary calcifications, the most frequent complication of MSK. (author). 13 refs.; 3 figs

  2. Axial tomography in live cell laser microscopy

    Science.gov (United States)

    Richter, Verena; Bruns, Sarah; Bruns, Thomas; Weber, Petra; Wagner, Michael; Cremer, Christoph; Schneckenburger, Herbert

    2017-09-01

    Single cell microscopy in a three-dimensional (3-D) environment is reported. Cells are grown in an agarose culture gel, located within microcapillaries and observed from different sides after adaptation of an innovative device for sample rotation. Thus, z-stacks can be recorded by confocal microscopy in different directions and used for illustration in 3-D. This gives additional information, since cells or organelles that appear superimposed in one direction, may be well resolved in another one. The method is tested and validated with single cells expressing a membrane or a mitochondrially associated green fluorescent protein, or cells accumulating fluorescent quantum dots. In addition, axial tomography supports measurements of cellular uptake and distribution of the anticancer drug doxorubicin in the nucleus (2 to 6 h after incubation) or the cytoplasm (24 h). This paper discusses that upon cell rotation an enhanced optical resolution in lateral direction compared to axial direction can be utilized to obtain an improved effective 3-D resolution, which represents an important step toward super-resolution microscopy of living cells.

  3. Axial vessel widening in arborescent monocots.

    Science.gov (United States)

    Petit, Giai; DeClerck, Fabrice A J; Carrer, Marco; Anfodillo, Tommaso

    2014-02-01

    Dicotyledons have evolved a strategy to compensate for the increase in hydraulic resistance to water transport with height growth by widening xylem conduits downwards. In monocots, the accumulation of hydraulic resistance with height should be similar, but the absence of secondary growth represents a strong limitation for the maintenance of xylem hydraulic efficiency during ontogeny. The hydraulic architecture of monocots has been studied but it is unclear how monocots arrange their axial vascular structure during ontogeny to compensate for increases in height. We measured the vessel lumina and estimated the hydraulic diameter (Dh) at different heights along the stem of two arborescent monocots, Bactris gasipaes (Kunth) and Guadua angustifolia (Kunth). For the former, we also estimated the variation in Dh along the leaf rachis. Hydraulic diameter increased basally from the stem apex to the base with a scaling exponent (b) in the range of those reported for dicot trees (b = 0.22 in B. gasipaes; b = 0.31 and 0.23 in G. angustifolia). In B. gasipaes, vessels decrease in Dh from the stem's centre towards the periphery, an opposite pattern compared with dicot trees. Along the leaf rachis, a pattern of increasing Dh basally was also found (b = 0.13). The hydraulic design of the monocots studied revealed an axial pattern of xylem conduits similar to those evolved by dicots to compensate and minimize the negative effect of root-to-leaf length on hydrodynamic resistance to water flow.

  4. Modeling the axial offset anomaly in PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Blok, J.; Chauffriat, S.; Frattini, P. [EPRI, Palo Alto, CA (United States)

    2002-07-01

    Axially un-symmetrical flux depression is defined as axial offset anomaly (AOA) in PWRs. The effect has only been observed in PWR reactor cores operated at high power duty. The threat of AOA limits the aggressiveness of core design, and in extreme form, the effect can decrease shutdown margin near end of cycle (EOC) sufficiently to mandate power reduction. AOA is ultimately the result of boron hideout on fuel. Studies have confirmed that sufficient boron hideout to produce measurable AOA requires relatively large amounts of corrosion products to deposit on the fuel. Because corrosion product deposition is favored in the boiling upper regions of the (high duty) core, the amount of boron uptake in these regions is large in proportion, and core reactivity is affected disproportionately in the upper region of the core. This paper explores possible mechanisms for deposition of corrosion products on fuel and the consequent incorporation of boron compounds. The proposed mechanisms are viewed in the context of corrosion product samples from the Callaway Cycle 9, one of the PWR fuel cycles that exhibited the most severe AOA to date. (author)

  5. Deformation Theory ( Lecture Notes )

    Czech Academy of Sciences Publication Activity Database

    Doubek, M.; Markl, Martin; Zima, P.

    2007-01-01

    Roč. 43, č. 5 (2007), s. 333-371 ISSN 0044-8753. [Winter School Geometry and Physics/27./. Srní, 13.01.2007-20.01.2007] R&D Projects: GA ČR GA201/05/2117 Institutional research plan: CEZ:AV0Z10190503 Keywords : deformation * Mauerer-Cartan equation * strongly homotopy Lie algebra Subject RIV: BA - General Mathematics

  6. Deformations of fractured rock

    International Nuclear Information System (INIS)

    Stephansson, O.

    1977-09-01

    Results of the DBM and FEM analysis in this study indicate that a suitable rock mass for repository of radioactive waste should be moderately jointed (about 1 joint/m 2 ) and surrounded by shear zones of the first order. This allowes for a gentle and flexible deformation under tectonic stresses and prevent the development of large cross-cutting failures in the repository area. (author)

  7. Normal modified stable processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2002-01-01

    This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...... Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process...

  8. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Letolle, R.; Mariotti, A.; Bariac, T.

    1991-06-01

    This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

  9. Regional Mapping of Aortic Wall Stress by Using Deformable, Motion-coherent Modeling based on Electrocardiography-gated Multidetector CT Angiography: Feasibility Study.

    Science.gov (United States)

    Mileto, Achille; Heye, Tobias J; Makar, Ryan A; Hurwitz, Lynne M; Marin, Daniele; Boll, Daniel T

    2016-07-01

    Purpose To investigate the feasibility of deformable, motion-coherent modeling based on electrocardiography-gated multidetector computed tomographic (CT) angiography of the thoracic aorta and to evaluate whether quantifiable information on aortic wall stress as a function of patient-specific cardiovascular parameters can be gained. Materials and Methods For this institutional review board-approved, HIPAA-compliant study, thoracic electrocardiography-gated dual-source multidetector CT angiographic images were used from 250 prospectively enrolled patients (150 men, 100 women; mean age, 79 years). On reconstructed 50-phase CT angiographic images, aortic strain and deformation were determined at seven cardiac and aortic locations. One-way analysis of variance was used by assessing the magnitude for longitudinal and axial strain and axial deformation, as well as time-resolved peak and maxima count for longitudinal strain and axial deformation. Interdependencies between aortic strain and deformation with extracted hemodynamic parameters were evaluated. Results With increasing heart rates, there was a significant decrease in longitudinal strain (P = .009, R(2) = 0.95) and a decrease in the number of longitudinal strain peaks (P < .001, R(2) = 0.79); however, a significant increase in axial deformation (P < .001, R(2) = 0.31) and axial strain (P = .009, R(2) = 0.61) was observed. Increasing aortic blood velocity led to increased longitudinal strain (P = .018, R(2) = 0.42) and longitudinal strain peak counts (P = .011, R(2) = 0.48). Pronounced motion in the longitudinal direction limited motion in the axial plane (P < .019, R(2) = 0.29-0.31). Conclusion The results of this study render a clinical basis and provide proof of principle for the use of deformable, motion-coherent modeling to provide quantitative information on physiological motion of the aorta under various hemodynamic circumstances. (©) RSNA, 2016 Online supplemental material is available for this article.

  10. Controlling thermal deformation by using composite materials having variable fiber volume fraction

    International Nuclear Information System (INIS)

    Bouremana, M.; Tounsi, A.; Kaci, A.; Mechab, I.

    2009-01-01

    In application, many thin structural components such as beams, plates and shells experience a through-thickness temperature variation. This temperature variation can produce both an in-plane expansion and an out-of-plane (bending) curvature. Given that these thin components interact with or connect to other components, we often wish to minimize the thermal deformation or match the thermal deformation of another component. This is accomplished by using a composite whose fibers have a negative axial thermal expansion coefficient. By varying the fiber volume fraction within a symmetric laminated beam to create a functionally graded material (FGM), certain thermal deformations can be controlled or tailored. Specifically, a beam can be designed which does not curve under a steady-state through-thickness temperature variation. Continuous gradation of the fiber volume fraction in the FGM layer is modelled in the form of a mth power polynomial of the coordinate axis in thickness direction of the beam. The beam results are independent of the actual temperature values, within the limitations of steady-state heat transfer and constant material properties. The influence of volume fiber fraction distributions are studied to match or eliminate an in-plane expansion coefficient, or to match a desired axial stiffness. Combining two fiber types to create a hybrid FGM can offer desirable increase in axial and bending stiffness while still retaining the useful thermal deformation behavior.

  11. Measurement technique of calcaneal varus from axial view radiograph

    Directory of Open Access Journals (Sweden)

    Thossart Harnroongroj

    2015-01-01

    Full Text Available Background: Medial displaced posterior calcaneal tubercle creates varus deformity of an intraarticular calcaneal fracture. The fracture involves posterior calcaneal facet and the calcaneal body so we developed a measurement technique representing the angle between posterior facet and long axis of calcaneus using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references to obtain calcaneal varus angle. Materials and Methods: 52 axial view calcaneal radiographs of 26 volunteers were studied. Angles between posterior facet and long axis of calcaneus were measured using the measurements 1 and 2. Angle of measurement 1, as gold standard, was obtained from long axis and posterior facet of calcaneus whereas measurement 2 was obtained from a line, perpendicular to apex curve of lateral cortex of the lateral malleolus and a line parallel to the longitudinal bone trabeculae of posterior calcaneal tubercle. No more than 3° of difference in the angle of both measurements was accepted. Reliability of the measurement 2 was statistically tested. Results: Angles of measurement 1 and 2 were 90.04° ± 4.00° and 90.58° ± 3.78°. Mean of different degrees of both measurements was 0.54° ± 2.31° with 95% of confidence interval: 0.10°-1.88°. The statistical analysis of measurement 1 and 2 showed more than 0.75 of ICC and 0.826 of Pearson correlation coefficient. Conclusion: Technique of measurement 2 using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references has strong reliability for representing the angle between long axis and posterior facet of calcaneus to achieve calcaneal varus angle.

  12. Measurement technique of calcaneal varus from axial view radiograph.

    Science.gov (United States)

    Harnroongroj, Thossart; Tangmanasakul, Akegapon; Choursamran, Nattapol; Sudjai, Narumol; Harnroongroj, Thos

    2015-01-01

    Medial displaced posterior calcaneal tubercle creates varus deformity of an intraarticular calcaneal fracture. The fracture involves posterior calcaneal facet and the calcaneal body so we developed a measurement technique representing the angle between posterior facet and long axis of calcaneus using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references to obtain calcaneal varus angle. 52 axial view calcaneal radiographs of 26 volunteers were studied. Angles between posterior facet and long axis of calcaneus were measured using the measurements 1 and 2. Angle of measurement 1, as gold standard, was obtained from long axis and posterior facet of calcaneus whereas measurement 2 was obtained from a line, perpendicular to apex curve of lateral cortex of the lateral malleolus and a line parallel to the longitudinal bone trabeculae of posterior calcaneal tubercle. No more than 3° of difference in the angle of both measurements was accepted. Reliability of the measurement 2 was statistically tested. Angles of measurement 1 and 2 were 90.04° ± 4.00° and 90.58° ± 3.78°. Mean of different degrees of both measurements was 0.54° ± 2.31° with 95% of confidence interval: 0.10°-1.88°. The statistical analysis of measurement 1 and 2 showed more than 0.75 of ICC and 0.826 of Pearson correlation coefficient. Technique of measurement 2 using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references has strong reliability for representing the angle between long axis and posterior facet of calcaneus to achieve calcaneal varus angle.

  13. Torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis).

    Science.gov (United States)

    Kerrigan, Shannon M; Kapatkin, Amy S; Garcia, Tanya C; Robinson, Duane A; Guzman, David Sanchez-Migallon; Stover, Susan M

    2018-04-01

    OBJECTIVE To describe the torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis). SAMPLE 16 cadaveric tibiotarsal bones from 8 red-tailed hawks. PROCEDURES 1 tibiotarsal bone from each bird was randomly assigned to be tested in torsion, and the contralateral bone was tested in axial compression. Intact bones were monotonically loaded in either torsion (n = 8) or axial compression (8) to failure. Mechanical variables were derived from load-deformation curves. Fracture configurations were described. Effects of sex, limb side, and bone dimensions on mechanical properties were assessed with a mixed-model ANOVA. Correlations between equivalent torsional and compressive properties were determined. RESULTS Limb side and bone dimensions were not associated with any mechanical property. During compression tests, mean ultimate cumulative energy and postyield energy for female bones were significantly greater than those for male bones. All 8 bones developed a spiral diaphyseal fracture and a metaphyseal fissure or fracture during torsional tests. During compression tests, all bones developed a crushed metaphysis and a fissure or comminuted fracture of the diaphysis. Positive correlations were apparent between most yield and ultimate torsional and compressive properties. CONCLUSIONS AND CLINICAL RELEVANCE The torsional and axial compressive properties of tibiotarsal bones described in this study can be used as a reference for investigations into fixation methods for tibiotarsal fractures in red-tailed hawks. Although the comminuted and spiral diaphyseal fractures induced in this study were consistent with those observed in clinical practice, the metaphyseal disruption observed was not and warrants further research.

  14. Ex vivo and in vitro determination of the axial rotational axis of the human thoracic spine.

    Science.gov (United States)

    Molnár, Szabolcs; Manó, Sándor; Kiss, László; Csernátony, Zoltán

    2006-12-15

    Different geometrical and biomechanical evaluations were performed to determine the axial rotational axis of the thoracic spine. Our research group has been dealing with the determination of the axial rotational axis of the thoracic spine. Here, we would like to present the geometrical and experimental results of our trials. With our experiments, we are trying to evaluate the contradictions of the related literature. In the present state, we know quite a lot about the biomechanics of healthy and pathologic spines. Nevertheless, for a seemingly simple question like the position of the axial rotation of the thoracic spine, the literature gives contradicting results. During correction of a scoliotic deformity, when trying to correct the pathologic rotation, not knowing the physiologic rotation can be hazardous. We wanted to clarify this question, so we examined the thoracic spine in many different ways. First, we examined the problem from a geometrical point of view then we modeled the different rotational axes by studying the change in volume of the spinal canal. Finally, we used cadaver spines that we rotated and examined with radiographs and digital pictures. Based on the results, we made the following establishments: most of the center points fell on the anterior half of the vertebral body or into the spinal canal, basically on the midsagittal axis of the vertebra. The rib cage has a significant effect on the place of the axis. After removing the ribs, the axis of axial rotation moved forward. After evaluating the results, we determined that the most likely place for the rotational axis is on the median-sagittal plane, in the anterior portion of the spinal canal.

  15. Deformation of confined poly(ethylene oxide) in multilayer films.

    Science.gov (United States)

    Lai, Chuan-Yar; Hiltner, Anne; Baer, Eric; Korley, LaShanda T J

    2012-04-01

    The effect of confinement on the deformation behavior of poly(ethylene oxide) (PEO) was studied using melt processed coextruded poly(ethylene-co-acrylic acid) (EAA) and PEO multilayer films with varying PEO layer thicknesses from 3600 to 25 nm. The deformation mechanism was found to shift as layer thickness was decreased between 510 and 125 nm, from typical axial alignment of the crystalline fraction, as seen in bulk materials, to nonuniform micronecking mechanisms found in solution-grown single crystals. This change was evaluated via tensile testing, wide-angle X-ray diffraction (WAXD), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). With the commercially relevant method of melt coextrusion, we were able to overcome the limitations to the testing of solution-grown single crystals, and the artifacts that occur from their handling, and bridged the gap in knowledge between thick bulk materials and thin single crystals.

  16. Nanoscale Deformable Optics

    Science.gov (United States)

    Strauss, Karl F.; Sheldon, Douglas J.

    2011-01-01

    Several missions and instruments in the conceptual design phase rely on the technique of interferometry to create detectable fringe patterns. The intimate emplacement of reflective material upon electron device cells based upon chalcogenide material technology permits high-speed, predictable deformation of the reflective surface to a subnanometer or finer resolution with a very high degree of accuracy. In this innovation, a layer of reflective material is deposited upon a wafer containing (perhaps in the millions) chalcogenic memory cells with the reflective material becoming the front surface of a mirror and the chalcogenic material becoming a means of selectively deforming the mirror by the application of heat to the chalcogenic material. By doing so, the mirror surface can deform anywhere from nil to nanometers in spots the size of a modern day memory cell, thereby permitting realtime tuning of mirror focus and reflectivity to mitigate aberrations caused elsewhere in the optical system. Modern foundry methods permit the design and manufacture of individual memory cells having an area of or equal to the Feature (F) size of the design (assume 65 nm). Fabrication rules and restraints generally require the instantiation of one memory cell to another no closer than 1.5 F, or, for this innovation, 90 nm from its neighbor in any direction. Chalcogenide is a semiconducting glass compound consisting of a combination of chalcogen ions, the ratios of which vary according to properties desired. It has been shown that the application of heat to cells of chalcogenic material cause a large alteration in resistance to the range of 4 orders of magnitude. It is this effect upon which chalcogenidebased commercial memories rely. Upon removal of the heat source, the chalcogenide rapidly cools and remains frozen in the excited state. It has also been shown that the chalcogenide expands in volume because of the applied heat, meaning that the coefficient of expansion of chalcogenic

  17. Analysing Stable Time Series

    National Research Council Canada - National Science Library

    Adler, Robert

    1997-01-01

    We describe how to take a stable, ARMA, time series through the various stages of model identification, parameter estimation, and diagnostic checking, and accompany the discussion with a goodly number...

  18. Multi-axial correction system in the treatment of radial club hand.

    Science.gov (United States)

    Bhat, Suneel B; Kamath, Atul F; Sehgal, Kriti; Horn, B David; Hosalkar, Harish S

    2009-12-01

    Radial club hand is a well-recognized congenital malformation characterized by hypoplasia of bone and soft tissue on the radial aspect of the forearm and hand. The modalities of treatment have traditionally varied from stretching casts with soft-tissue procedures to the use of multiple corrective osteotomies. These osteotomies can be stabilized by a variety of methods, including external fixators that allow the possibility of gradual distraction with neohistiogenesis. This current study outlines the usage of one such device (multi-axial correction system [MAC]) in the management of deformity associated with severe radial club hand. Three consecutive cases of unilateral or bilateral severe (Bayne type IV) congenital radial club hand were corrected using MAC fixation in the last 5 years. This is a retrospective review of all three cases. Data parameters included: patient demographics, presentation findings, degree of deformity, amount of correction/lengthening, length of procedure, length of treatment, and associated complications. The surgical technique is described in detail for the benefit of the readership. The three patients with severe congenital radial club hand had a total of four limb involvements that underwent correction using osteotomies and usage of the MAC device for external fixation. All three patients underwent successful correction of deformity with the restoration of alignment, lengthening of forearm for improvement of function, and stabilization of the wrist (mean duration, mean lengthening, mean time to consolidation). The MAC system was well tolerated in all patients and associated complications were limited. The MAC fixator seems to be a good alternative modality of stabilization and correction for severe congenital radial club hand deformities. Its usage is fairly simple and it provides the ease of application of a mono-lateral fixator with far superior three-dimensional control, like the circular external fixator. We recommend that

  19. Axial dispersion in a Kureha Crystal Purifier (KCP)

    Science.gov (United States)

    Otawara, K.; Matsuoka, T.

    2002-04-01

    It is widely accepted that the degree of axial back-mixing in the equipment affects the performance of a column crystallizer. Specifically, small such mixing is inevitable for obtaining highly pure crystal. In fact, it is believed that scale-up of some column crystallizers has been terminated due to the large axial back-mixing or maldistribution. Thus, experiments have been performed for estimating axial dispersion coefficients of liquid phase representing axial back-mixing in the column of a Kureha Crystal Purifier (KCP). The effect of the column diameter on such coefficients has been investigated and it has become evident that the axial back-mixing in the column is more significant in the larger column. Nevertheless, the results have also indicated that the axial back-mixing in KCPs of industrial sizes can be substantially smaller than those in other types of column crystallizers.

  20. Axial stress corrosion cracking forming method to metal tube

    International Nuclear Information System (INIS)

    Araki, Kumiko

    1998-01-01

    Generally, it is more difficult in a metal tube, to intentionally cause a stress corrosion cracking in axial direction than in circumferential direction. In the present invention, a bevel is formed on a metal tube and welding is conducted in circumferential direction along the bevel, and welding is conducted in axial direction partially to the portion welded in circumferential direction. Namely, a bevel is formed in circumferential direction to an abutting portion of thick-walled metal tubes with each other, welding is conducted in circumferential direction along the bevel, and welding is conducted in axial direction partially to a portion welded in circumferential direction. With such procedures, since tensile stress in the circumferential direction is increased partially at a portion welded in axial direction, stress corrosion cracking is caused in axial direction at the portion. Then, stress corrosion cracking in axial direction can thus be formed on the thick-walled metal tube. (N.H.)

  1. Revisiting the vector and axial-vector vacuum susceptibilities

    International Nuclear Information System (INIS)

    Chang Lei; Liu Yuxin; Sun Weimin; Zong Hongshi

    2008-01-01

    We re-investigate the vector and axial-vector vacuum susceptibilities by taking advantage of the vector and axial-vector Ward-Takahashi identities. We show analytically that, in the chiral limit, the vector vacuum susceptibility is zero and the axial-vector vacuum susceptibility equals three fourths of the square of the pion decay constant. Besides, our analysis reproduces the Weinberg sum rule

  2. Aerodynamic Modelling and Optimization of Axial Fans

    DEFF Research Database (Denmark)

    Sørensen, Dan Nørtoft

    A numerically efficient mathematical model for the aerodynamics oflow speed axial fans of the arbitrary vortex flow type has been developed.The model is based on a blade-element principle, whereby therotor is divided into a number of annular streamtubes.For each of these streamtubes relations...... and integrated propertiesshow that the computed results agree well with the measurements.Integrating a rotor-only version of the aerodynamic modelwith an algorithm for numerical designoptimization, enables the finding of an optimum fan rotor.The angular velocity of the rotor, the hub radius and the spanwise...... of fan efficiency in a design interval of flow rates,thus designinga fan which operates well over a range of different flow conditions.The optimization scheme was used to investigate the dependence ofmaximum efficiency on1: the number of blades,2: the width of the design interval and3: the hub radius...

  3. Geometric inequalities for axially symmetric black holes

    International Nuclear Information System (INIS)

    Dain, Sergio

    2012-01-01

    A geometric inequality in general relativity relates quantities that have both a physical interpretation and a geometrical definition. It is well known that the parameters that characterize the Kerr-Newman black hole satisfy several important geometric inequalities. Remarkably enough, some of these inequalities also hold for dynamical black holes. This kind of inequalities play an important role in the characterization of the gravitational collapse; they are closely related with the cosmic censorship conjecture. Axially symmetric black holes are the natural candidates to study these inequalities because the quasi-local angular momentum is well defined for them. We review recent results in this subject and we also describe the main ideas behind the proofs. Finally, a list of relevant open problems is presented. (topical review)

  4. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The objects of this invention are first to reduce the time required to obtain statistically significant data in trans-axial tomographic radioisotope scanning using a scintillation camera. Secondly, to provide a scintillation camera system to increase the rate of acceptance of radioactive events to contribute to the positional information obtainable from a known radiation source without sacrificing spatial resolution. Thirdly to reduce the scanning time without loss of image clarity. The system described comprises a scintillation camera detector, means for moving this in orbit about a cranial-caudal axis relative to a patient and a collimator having septa defining apertures such that gamma rays perpendicular to the axis are admitted with high spatial resolution, parallel to the axis with low resolution. The septa may be made of strips of lead. Detailed descriptions are given. (U.K.)

  5. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The principal problem in trans-axial tomographic radioisotope scanning is the length of time required to obtain meaningful data. Patient movement and radioisotope migration during the scanning period can cause distortion of the image. The object of this invention is to reduce the scanning time without degrading the images obtained. A system is described in which a scintillation camera detector is moved to an orbit about the cranial-caudal axis relative to the patient. A collimator is used in which lead septa are arranged so as to admit gamma rays travelling perpendicular to this axis with high spatial resolution and those travelling in the direction of the axis with low spatial resolution, thus increasing the rate of acceptance of radioactive events to contribute to the positional information obtainable without sacrificing spatial resolution. (author)

  6. Axial flux data for fuel measurement

    Energy Technology Data Exchange (ETDEWEB)

    Popovich, R.P.

    1964-02-11

    A survey of the PITA-18 nonpoisonous spline program was conducted in conjunction with a study to determine the best method of eliminating the variability of axial flux on the fuel performance parameter, q. The results of this survey and the conclusions reached in the rupture coefficient study were found to be inter-dependent such that both are presented in this report. The data from the PITA-18 nonpoisonous spline program, as received, is the output of the NOLA-2 computer program. One quantity of interest is the rupture potential relative to a cosine, commonly referred to as the relative rupture potential. As programmed, the relative rupture potential, which was derived by applying the rupture model to individual fuel elements, might be expected to vary linearly with the rupture rate. The use of the relative rupture potential was studied over the period of July 1962 through December 1963. The results of this study are presented.

  7. Composite Axial Flow Propulsor for Small Aircraft

    Directory of Open Access Journals (Sweden)

    R. Poul

    2005-01-01

    Full Text Available This work focuses on the design of an axial flow ducted fan driven by a reciprocating engine. The solution minimizes the turbulization of the flow around the aircraft. The fan has a rotor - stator configuration. Due to the need for low weight of the fan, a carbon/epoxy composite material was chosen for the blades and the driving shaft.The fan is designed for optimal isentropic efficiency and free vortex flow. A stress analysis of the rotor blade was performed using the Finite Element  Method. The skin of the blade is calculated as a laminate and the foam core as a solid. A static and dynamic analysis were made. The RTM technology is compared with other technologies and is described in detail. 

  8. Estimation of ocular volume from axial length.

    Science.gov (United States)

    Nagra, Manbir; Gilmartin, Bernard; Logan, Nicola S

    2014-12-01

    To determine which biometric parameters provide optimum predictive power for ocular volume. Sixty-seven adult subjects were scanned with a Siemens 3-T MRI scanner. Mean spherical error (MSE) (D) was measured with a Shin-Nippon autorefractor and a Zeiss IOLMaster used to measure (mm) axial length (AL), anterior chamber depth (ACD) and corneal radius (CR). Total ocular volume (TOV) was calculated from T2-weighted MRIs (voxel size 1.0 mm(3)) using an automatic voxel counting and shading algorithm. Each MR slice was subsequently edited manually in the axial, sagittal and coronal plane, the latter enabling location of the posterior pole of the crystalline lens and partitioning of TOV into anterior (AV) and posterior volume (PV) regions. Mean values (±SD) for MSE (D), AL (mm), ACD (mm) and CR (mm) were -2.62±3.83, 24.51±1.47, 3.55±0.34 and 7.75±0.28, respectively. Mean values (±SD) for TOV, AV and PV (mm(3)) were 8168.21±1141.86, 1099.40±139.24 and 7068.82±1134.05, respectively. TOV showed significant correlation with MSE, AL, PV (all p<0.001), CR (p=0.043) and ACD (p=0.024). Bar CR, the correlations were shown to be wholly attributable to variation in PV. Multiple linear regression indicated that the combination of AL and CR provided optimum R(2) values of 79.4% for TOV. Clinically useful estimations of ocular volume can be obtained from measurement of AL and CR. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  9. Self-consistent separable random-phase approximation for Skyrme forces: Giant resonances in axial nuclei

    International Nuclear Information System (INIS)

    Nesterenko, V. O.; Dolci, D. S.; Kleinig, W.; Kvasil, J.; Vesely, P.; Reinhard, P.-G.

    2006-01-01

    We formulate the self-consistent separable random phase approximation (SRPA) method and specify it for Skyrme forces with pairing for the case of axially symmetric deformed nuclei. The factorization of the residual interaction allows diagonalization of high-ranking RPA matrices to be avoided, which dramatically reduces the computational expense. This advantage is crucial for the systems with a huge configuration space, first of all for deformed nuclei. SRPA self-consistently takes into account the contributions of both time-even and time-odd Skyrme terms as well as of the Coulomb force and pairing. The method is implemented to describe isovector E1 and isoscalar E2 giant resonances in a representative set of deformed nuclei: 154 Sm, 238 U, and 254 No. Four different Skyrme parameterizations (SkT6, SkM*, SLy6, and SkI3) are employed to explore the dependence of the strength distributions on some basic characteristics of the Skyrme functional and nuclear matter. In particular, we discuss the role of isoscalar and isovector effective masses and their relation to time-odd contributions. The high sensitivity of the right flank of E1 resonance to different Skyrme forces and the related artificial structure effects are analyzed

  10. Vertebral deformities in hatchery-reared and wild-caught juvenile Japanese flounder, Paralichthys olivaceus

    Science.gov (United States)

    Lü, Hongjian; Zhang, Xiumei; Fu, Mei; Xi, Dan; Su, Shengqi; Yao, Weizhi

    2015-01-01

    The present study compared vertebral deformities of hatchery-reared and wild-caught juvenile Japanese flounder, Paralichthys olivaceus. A total of 362 hatchery-reared flounder (total length 122.5-155.8 mm) were collected from three commercial hatcheries located in Yantai, East China, and 89 wild fish (total length 124.7-161.3 mm) were caught off Yangma Island near Yantai City (37°27'N, 121°36'E). All the fish were dissected, photographed, and images of the axial skeleton were examined for vertebral deformities. Compared with wild-caught flounder in which no deformed vertebrae were detected, 48 (13.3%) hatcheryreared fish had deformed vertebrae. The deformities were classified as compression, compression-ankylosis, and dislocation-ankylosis. The vertebral deformities were mainly localized between post-cranial vertebra 1 and 3, with vertebrae number 1 as the most commonly deformed. The causative factors leading to vertebral deformities in reared Japanese flounder may be related to unfavorable temperature conditions, inflammation, damage, or rupture to the intervertebral ligaments under rearing conditions. Furthermore, no significant difference in the total number of vertebral bodies was observed between wild-caught (38.8±0.4) and hatchery-reared flounder (38.1±0.9) ( P>0.05). However, the number of vertebral bodies of hatchery-reared and wild-caught flounder ranged from 35 to 39 and from 38 to 39, respectively.

  11. Deformable Simplicial Complexes

    DEFF Research Database (Denmark)

    Misztal, Marek Krzysztof

    triangles/tetrahedra marked as outside from those marked as inside. Such an approach allows for robust topological adaptivity. Among other advantages of the deformable simplicial complexes there are: space adaptivity, ability to handle and preserve sharp features, possibility for topology control. We....... One particular advantage of DSC is the fact that as an alternative to topology adaptivity, topology control is also possible. This is exploited in the construction of cut loci on tori where a front expands from a single point on a torus and stops when it self-intersects....

  12. Axial and coronal orientation of subaxial cervical zygapophysial joints and their effect on axial rotation and lateral bending.

    Science.gov (United States)

    Hsu, Wen-Hsing; Benzel, Edward C; Chen, Tzu-Yung; Chen, Yao-Liang

    2008-10-15

    Computerized tomography and image processing methodologies were used to analyze the axial and coronal orientation of cervical zygapophysial joints in asymptomatic adults. Surface motions of axial rotation and lateral bending were simulated. The study was designed to obtain the normal distribution and variation of facet orientation (FO) in axial and coronal planes to investigate factors affecting FO and to study the effects of FO on axial rotation and lateral bending. The FO of the subaxial cervical spine is usually evaluated in the sagittal plane. Cervical spine axial and coronal FO is usually considered to be horizontal. The literature reveals no statistical data for axial or coronal FO. Serial thin-sliced computed tomography scans of the cervical spine in asymptomatic adults were input into Image J, National Institutes of Health, image processing software. Bilateral zygapophysial joint angles from C2-C3 to C6-C7 were measured in the axial and coronal planes and collected from 100 subjects. The effect of gender, age, and correlation was analyzed. The surface motions of axial rotation and lateral bending were simulated in Abaqus CAE 6.5. Mathematical facet contact and range of motion were computed. The FO was widely distributed at each level. Gender had no significant association with FO. Age affected FO at most levels. Axial and coronal FO were significantly correlated. The zygapophysial joint of internally rotated/inverted FO contacted more perpendicularly to each other, and mathematical range of motion was smaller. The axial or coronal FO of the subaxial cervical spine was found with more variability. Age was significantly related to FO. Geometrically, internally rotated/inverted FO of axial rotation/lateral bending was morerestricted. The extent of axial rotation and lateral bending was correlated with each other.

  13. The Space-Time Fractal Feature of Deformation at Convex Corner of Deep Foundation Pit

    Directory of Open Access Journals (Sweden)

    ZHAO Shun-li

    2016-03-01

    Full Text Available The study on the space-time feature of foundation pit deformation has important significance to ensure the stability of foundation pit engineering. In the present study, the relationship between the space-time fractal feature of foundation pit deformation and the stability of the foundation pit is expressed with simple indexes, such as the time and position of the maximum value of deformation. By combining the concrete engineering example, the fractal theory is introduced, and the correlation dimension is calculated with the measured deformation data for a period of time. By combining the concrete engineering example, the fractal theory was introduced, and used the correlation dimension calculated with the measured deformation data to analyze the space-time fractal feature of deformation at convex corner. Further researched on the relationship between the correlation dimension of the foundation pit deformation and the stability of foundation pit. The research showed that the correlation dimension could reveal the complex space-time feature of the foundation pit deformation. From the aspects of time, the correlation dimension is related to the foundation pit condition, construction disturbance, the change of supporting structure and so on, and has a certain degree of decline with time. From the aspects of space, the difference of correlation dimension between stable and unstable regions is relatively large while there is little difference in the stability region. With the correlation dimension, it is more easily to identify the stable and the unstable regions of the foundation pit, compared with the accumulated deformation.

  14. Calcium stable isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

    2016-08-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  15. Nuclear fuel deformation phenomena

    International Nuclear Information System (INIS)

    Van Brutzel, L.; Dingreville, R.; Bartel, T.J.

    2015-01-01

    Nuclear fuel encounters severe thermomechanical environments. Its mechanical response is profoundly influenced by an underlying heterogeneous microstructure but also inherently dependent on the temperature and stress level histories. The ability to adequately simulate the response of such microstructures, to elucidate the associated macroscopic response in such extreme environments is crucial for predicting both performance and transient fuel mechanical responses. This chapter discusses key physical phenomena and the status of current modelling techniques to evaluate and predict fuel deformations: creep, swelling, cracking and pellet-clad interaction. This chapter only deals with nuclear fuel; deformations of cladding materials are discussed elsewhere. An obvious need for a multi-physics and multi-scale approach to develop a fundamental understanding of properties of complex nuclear fuel materials is presented. The development of such advanced multi-scale mechanistic frameworks should include either an explicit (domain decomposition, homogenisation, etc.) or implicit (scaling laws, hand-shaking,...) linkage between the different time and length scales involved, in order to accurately predict the fuel thermomechanical response for a wide range of operating conditions and fuel types (including Gen-IV and TRU). (authors)

  16. Development of an axial suspended AMB experimental bench for load and disturbance tests

    Directory of Open Access Journals (Sweden)

    R. Gouws

    2015-06-01

    Full Text Available This paper provides the development of an axial suspended active magnetic bearing (AMB experimental bench for load and disturbance tests. This test bench must be capable of levitating a 2 kg steel disc at a stable working distance of 3 mm and a maximum attraction distance of 6 mm. The suspension is accomplished by two electromagnets producing upward and downward attraction forces to support the steel disc. An inductive sensor measures the position of the steel disc and relays this to a PC based controller board (dSPACE® controller. The control system uses this information to regulate the electromagnetic force on the steel disc. The intent is to construct this system using relatively low-cost, low-precision components, and still be able to stably levitate the 2 kg steel disc with high precision. The dSPACE® software (ControlDesk® was used for data acquisition. In this paper, an overview of the system design is presented, followed by the axial AMB model design, inductive sensor design, actuating unit design and controller development and implementation. The paper concludes with results obtained from the dSPACE® controller and evaluation of the axial suspended AMB experimental bench with load and disturbance tests.

  17. Rotary deformity in degenerative spondylolisthesis

    International Nuclear Information System (INIS)

    Kang, Sung Gwon; Kim, Jeong; Kho, Hyen Sim; Yun, Sung Su; Oh, Jae Hee; Byen, Ju Nam; Kim, Young Chul

    1994-01-01

    We studied to determine whether the degenerative spondylolisthesis has rotary deformity in addition to forward displacement. We have made analysis of difference of rotary deformity between the 31 study groups of symptomatic degenerative spondylolisthesis and 31 control groups without any symptom, statistically. We also reviewed CT findings in 15 study groups. The mean rotary deformity in study groups was 6.1 degree(the standard deviation is 5.20), and the mean rotary deformity in control groups was 2.52 degree(the standard deviation is 2.16)(p < 0.01). The rotary deformity can be accompanied with degenerative spondylolisthesis. We may consider the rotary deformity as a cause of symptomatic degenerative spondylolisthesis in case that any other cause is not detected

  18. Rotary deformity in degenerative spondylolisthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung Gwon; Kim, Jeong; Kho, Hyen Sim; Yun, Sung Su; Oh, Jae Hee; Byen, Ju Nam; Kim, Young Chul [Chosun University College of Medicine, Gwangju (Korea, Republic of)

    1994-05-15

    We studied to determine whether the degenerative spondylolisthesis has rotary deformity in addition to forward displacement. We have made analysis of difference of rotary deformity between the 31 study groups of symptomatic degenerative spondylolisthesis and 31 control groups without any symptom, statistically. We also reviewed CT findings in 15 study groups. The mean rotary deformity in study groups was 6.1 degree(the standard deviation is 5.20), and the mean rotary deformity in control groups was 2.52 degree(the standard deviation is 2.16)(p < 0.01). The rotary deformity can be accompanied with degenerative spondylolisthesis. We may consider the rotary deformity as a cause of symptomatic degenerative spondylolisthesis in case that any other cause is not detected.

  19. Neutron halo in deformed nuclei

    International Nuclear Information System (INIS)

    Zhou Shangui; Meng Jie; Ring, P.; Zhao Enguang

    2010-01-01

    Halo phenomena in deformed nuclei are investigated within a deformed relativistic Hartree Bogoliubov (DRHB) theory. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Contributions of the halo, deformation effects, and large spatial extensions of these systems are described in a fully self-consistent way by the DRHB equations in a spherical Woods-Saxon basis with the proper asymptotic behavior at a large distance from the nuclear center. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nucleus 44 Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the occurrence of this decoupling effects are discussed.

  20. Computing the effect of plastic deformation of piping on pressure transient propagation

    International Nuclear Information System (INIS)

    Youngdahl, C.K.; Kot, C.A.

    1977-01-01

    The computer program PTA-1 performs pressure-transient analysis of large piping networks using the one-dimensional method of characteristics applied to a fluid-hammer formulation. The effect of elastic-plastic deformation of piping on pulse propagation is included in the computation. Each pipe is modeled as a series of rings, neglecting axial effects, bending moments, and inertia. The fluid wave speed is a function of pipe deformation and, consequently, of position and time. Comparison with existing experimental data indicate that this simple fluid-structure interaction model gives suprisingly accurate results for both pressure histories in the fluid and strain histories in the piping

  1. Radiologic evaluation of foot deformities

    International Nuclear Information System (INIS)

    Erlemann, R.; Fischedick, A.R.; Peters, P.E.

    1986-01-01

    In order to analyze foot deformities, the foot is divided into three compartments. Their normal and pathological positions are defined by the alignment of the bones' axes. The various foot deformities can be put down to a malalignment of the particular compartments. X-ray analysis of the malalignment allows a diagnosis to be made. The most important congenital and acquired foot deformities are discussed. (orig.) [de

  2. q-deformed Brownian motion

    CERN Document Server

    Man'ko, V I

    1993-01-01

    Brownian motion may be embedded in the Fock space of bosonic free field in one dimension.Extending this correspondence to a family of creation and annihilation operators satisfying a q-deformed algebra, the notion of q-deformation is carried from the algebra to the domain of stochastic processes.The properties of q-deformed Brownian motion, in particular its non-Gaussian nature and cumulant structure,are established.

  3. Line profile analyses of a martensitic steel during continuous and stepwise tensile deformations

    Science.gov (United States)

    Kawasaki, T.; Harjo, S.; Gong, W.; Aizawa, K.

    2016-09-01

    Dislocation characteristics in an as-quenched 22SiMn2TiB martensitic steel during tensile deformation were monitored by in-situ time-of-flight neutron diffraction combined with the Convolutional Multiple Whole Profile fitting analysis. Two loading conditions, continuous and stepwise followed by unloading, were adopted in the experiments. The diffraction patterns both in the loading (axial) and the transversal directions were measured simultaneously. The dislocation densities obtained from the experiments behaved differently in two loading conditions and in two measured directions, respectively. The different behaviour was mainly due to the increase of intergranular strains with the increase of deformation, and the profiles measured in the axial direction in the loading condition of stepwise followed by unloading gave most reliable dislocation characteristics among the profiles measured in other conditions.

  4. Study of the low-energy neutron inelastic scattering in deformed transitional nuclei: 186W

    International Nuclear Information System (INIS)

    Diaz, J.R.F.; Solorzano, R.C.

    1983-01-01

    A study of inelastic neutron scattering by the nucleus 186 W at an incident energy of 2.75 MeV using the coupled-channel method has been made. Consideration is made of the 2 + (0.122 MeV), 4 + (0.3966 MeV), 2 + (0.7375 MeV), 3 + (0.8618 MeV) and 4 + (1.031 MeV) excited states. It is shown that in this energy range the process may be described satisfactorily by the Davydov-Filippov model, considering 186 W as a deformed nucleus with non-axial symmetry, given the quadrupole and hexadecapole deformations. The scattering process through the compound nucleus is calculated according to the Hauser-Feshbach formula. It is shown that the presence of direct processes may be partly due to the non-axiality of 186 W. (author)

  5. Deformable paper origami optoelectronic devices

    KAUST Repository

    He, Jr-Hau

    2017-01-19

    Deformable optoelectronic devices are provided, including photodetectors, photodiodes, and photovoltaic cells. The devices can be made on a variety of paper substrates, and can include a plurality of fold segments in the paper substrate creating a deformable pattern. Thin electrode layers and semiconductor nanowire layers can be attached to the substrate, creating the optoelectronic device. The devices can be highly deformable, e.g. capable of undergoing strains of 500% or more, bending angles of 25° or more, and/or twist angles of 270° or more. Methods of making the deformable optoelectronic devices and methods of using, e.g. as a photodetector, are also provided.

  6. q-deformed Minkowski space

    International Nuclear Information System (INIS)

    Ogievetsky, O.; Pillin, M.; Schmidke, W.B.; Wess, J.; Zumino, B.

    1993-01-01

    In this lecture I discuss the algebraic structure of a q-deformed four-vector space. It serves as a good example of quantizing Minkowski space. To give a physical interpretation of such a quantized Minkowski space we construct the Hilbert space representation and find that the relevant time and space operators have a discrete spectrum. Thus the q-deformed Minkowski space has a lattice structure. Nevertheless this lattice structure is compatible with the operation of q-deformed Lorentz transformations. The generators of the q-deformed Lorentz group can be represented as linear operators in the same Hilbert space. (orig.)

  7. Deformation behaviour of turbine foundations

    International Nuclear Information System (INIS)

    Koch, W.; Klitzing, R.; Pietzonka, R.; Wehr, J.

    1979-01-01

    The effects of foundation deformation on alignment in turbine generator sets have gained significance with the transition to modern units at the limit of design possibilities. It is therefore necessary to obtain clarification about the remaining operational variations of turbine foundations. Static measurement programmes, which cover both deformation processes as well as individual conditions of deformation are described in the paper. In order to explain the deformations measured structural engineering model calculations are being undertaken which indicate the effect of limiting factors. (orig.) [de

  8. Equation of motion for the axial gravitational superfield

    International Nuclear Information System (INIS)

    Ogievetsky, V.; Sokatchev, E.

    1980-01-01

    Transformation properties of the axial supergravitational field variants are investigated. The equation of motion for the axial gravitational superfield is derived by direct variation of the N = 1 supergravity action. The left-hand side of this equation is a component of the torsion tensor, and the right-hand side is the supercurrent. The question about the cosmological term in supergravity is discussed

  9. Thermodynamically stable blue phases.

    Science.gov (United States)

    Castles, F; Morris, S M; Terentjev, E M; Coles, H J

    2010-04-16

    We show theoretically that flexoelectricity stabilizes blue phases in chiral liquid crystals. Induced internal polarization reduces the elastic energy cost of splay and bend deformations surrounding singular lines in the director field. The energy of regions of double twist is unchanged. This in turn reduces the free energy of the blue phase with respect to that of the chiral nematic phase, leading to stability over a wider temperature range. The theory explains the discovery of large temperature range blue phases in highly flexoelectric "bimesogenic" and "bent-core" materials, and predicts how this range may be increased further.

  10. Effect of vorticity on polycrystalline ice deformation

    Science.gov (United States)

    Llorens, Maria-Gema; Griera, Albert; Steinbach, Florian; Bons, Paul D.; Gomez-Rivas, Enrique; Jansen, Daniela; Lebensohn, Ricardo A.; Weikusat, Ilka

    2017-04-01

    results further show that subgrain boundaries can be developed by the activity of the non-basal slip systems. The implementation of the polygonisation routine reduces grain size and SPO, but does not significantly change the final LPO, because newly nucleated grains approximately keep the c-axis orientations of their parental grains. However, it enables the establishment of an equilibrium grain size, and therefore the differential stress reaches a steady-state. Lebensohn. 2001 N-site modelling of a 3D viscoplastic polycrystal using fast Fourier transform. Acta Materialia, 49(14), 2723-2737. Llorens, et al., 2016a. Dynamic recrystallisation of ice aggregates during co-axial viscoplastic deformation: a numerical approach. Journal of Glaciology, 62(232), 359-377. Llorens, et al., 2016b. Full-field predictions of ice dynamic recrystallisation under simple shear conditions, Earth and Planetary Science Letters, 450, 233-242. Llorens, et al., 2017. Dynamic recrystallisation during deformation of polycrystalline ice: insights from numerical simulations, Philosophical Transactions of the Royal Society A, 375 (2086), 20150346.

  11. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 9. Evolutionary Stable Strategy: Application of Nash Equilibrium in Biology. General ... Using some examples of classical games, we show how evolutionary game theory can help understand behavioural decisions of animals.

  12. The Stable Concordance Genus

    OpenAIRE

    Kearney, M. Kate

    2013-01-01

    The concordance genus of a knot is the least genus of any knot in its concordance class. Although difficult to compute, it is a useful invariant that highlights the distinction between the three-genus and four-genus. In this paper we define and discuss the stable concordance genus of a knot, which describes the behavior of the concordance genus under connected sum.

  13. Manifolds admitting stable forms

    Czech Academy of Sciences Publication Activity Database

    Le, Hong-Van; Panák, Martin; Vanžura, Jiří

    2008-01-01

    Roč. 49, č. 1 (2008), s. 101-11 ISSN 0010-2628 R&D Projects: GA ČR(CZ) GP201/05/P088 Institutional research plan: CEZ:AV0Z10190503 Keywords : stable forms * automorphism groups Subject RIV: BA - General Mathematics

  14. Stable isotope studies

    International Nuclear Information System (INIS)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

  15. Interactive Stable Ray Tracing

    DEFF Research Database (Denmark)

    Dal Corso, Alessandro; Salvi, Marco; Kolb, Craig

    2017-01-01

    Interactive ray tracing applications running on commodity hardware can suffer from objectionable temporal artifacts due to a low sample count. We introduce stable ray tracing, a technique that improves temporal stability without the over-blurring and ghosting artifacts typical of temporal post-pr...

  16. The stable subgroup graph

    Directory of Open Access Journals (Sweden)

    Behnaz Tolue

    2018-07-01

    Full Text Available In this paper we introduce stable subgroup graph associated to the group $G$. It is a graph with vertex set all subgroups of $G$ and two distinct subgroups $H_1$ and $H_2$ are adjacent if $St_{G}(H_1\\cap H_2\

  17. Bi-axial quartz as a stress indicator

    Science.gov (United States)

    Starkey, John

    2000-03-01

    Experiments confirm that stress causes quartz to become biaxial with the optical axial plane parallel to the direction of maximum applied stress. Five tectonites were studied for which published data indicate strong patterns of preferred orientation of quartz. Conoscopic investigation, using an optical universal stage, reveals that the quartz in these rocks is biaxial with the 2V as large as 22°. The optic axial planes display strong patterns of preferred orientation. In the natural tectonites the maximum stress directions deduced from the orientations of the optical axial planes cannot be correlated with the supposed tectonic framework responsible for the quartz orientation fabric. The ease with which quartz can be made biaxial experimentally suggests that the orientation of the optic axial planes may be sensitive to tectonic events which affected the rocks subsequent to the development of the quartz orientation fabrics. The analysis of the orientation of optic axial planes in biaxial quartz may provide a tool for the investigation of neotectonics.

  18. Light and heavy touch reduces postural sway and modifies axial tone in Parkinson’s disease

    Science.gov (United States)

    Franzén, Erika; Paquette, Caroline; Gurfinkel, Victor; Horak, Fay

    2014-01-01

    Background Light touch with a stable object reduces postural sway by increasing axial postural tone in healthy subjects. However, it is unknown whether subjects with Parkinson’s disease (PD), who have more postural sway and higher axial postural tone than healthy subjects, can benefit from haptic touch. Objective To investigate the effect of light and heavy touch on postural stability and hip tone in subjects with PD. Methods Fourteen subjects with mid-stage PD, and 14 healthy control subjects were evaluated during quiet standing with eyes closed with their arms: 1) crossed, 2) lightly touching a fixed rigid bar in front of them and 3) firmly gripping the bar. Postural sway was measured with a forceplate and axial hip tone was quantified using a unique device that measures the resistance of the hips to yaw rotation while maintaining active stance. Results Subjects with PD significantly decreased their postural sway with light or heavy touch (ptouch, hip tone was larger in PD subjects. With touch, however, tone values were similar in both groups. This change in hip tone with touch was highly correlated with the initial amount of tone (PD: r=− 0.72 to −0.95 and controls: r=−0.74 to−0.85). Conclusions We showed, for the first time, that subjects with PD benefit from touch similarly to control subjects and that despite higher axial postural tone, PD subjects are able to modulate their tone with touch. Future studies should investigate the complex relationship between touch and postural tone. PMID:22415944

  19. Angular displacement and deformation analyses using speckle-based wavefront sensor

    DEFF Research Database (Denmark)

    Almoro, Percival; Giancarlo, Pedrini; Arun, Anand

    2009-01-01

    Wavefronts incident on a random phase plate are reconstructed via phase retrieval utilizing axially displaced speckle intensity measurements and the wave propagation equation. Retrieved phases and phase subtraction facilitate the investigations of wavefronts from test objects before and after und...... thermal loading. The technique offers simple, high resolution, noncontact, and whole field evaluation of three-dimensional objects before and after undergoing rotation or deformation. (C) 2009 Optical Society of America...

  20. Modeling the progressive axial crushing of foam-filled aluminum tubes using smooth particle hydrodynamics and coupled finite element model/smooth particle hydrodynamics

    OpenAIRE

    Aktay, Levent; Johnson, Alastair F.; Toksoy, Ahmet Kaan; Kröplin, Bernd Helmut; Güden, Mustafa

    2008-01-01

    As alternatives to the classical finite element model (FEM), a meshless smooth particle hydrodynamics (SPH) method, in which the discrete particles represent a solid domain, and a coupled FEM/SPH modeling technique were investigated for the numerical simulation of the quasi-static axial crushing of polystyrene foam-filled aluminum thin-walled aluminum tubes. The results of numerical simulations, load-deformation histories, fold lengths and specific absorbed energies, were found to show satisf...

  1. Deformations of surface singularities

    CERN Document Server

    Szilárd, ágnes

    2013-01-01

    The present publication contains a special collection of research and review articles on deformations of surface singularities, that put together serve as an introductory survey of results and methods of the theory, as well as open problems, important examples and connections to other areas of mathematics. The aim is to collect material that will help mathematicians already working or wishing to work in this area to deepen their insight and eliminate the technical barriers in this learning process. This also is supported by review articles providing some global picture and an abundance of examples. Additionally, we introduce some material which emphasizes the newly found relationship with the theory of Stein fillings and symplectic geometry.  This links two main theories of mathematics: low dimensional topology and algebraic geometry. The theory of normal surface singularities is a distinguished part of analytic or algebraic geometry with several important results, its own technical machinery, and several op...

  2. Relation between axial length and ocular parameters

    Directory of Open Access Journals (Sweden)

    Xue-Qiu Yang

    2013-09-01

    Full Text Available AIM: To investigatethe relation between axial length(AL, age and ocular parameters.METHODS: A total of 360 subjects(360 eyeswith emmetropia or myopia were recruited. Refraction, center corneal thickness(CCT, AL, intraocular pressure(IOPwere measured by automatic-refractor, Pachymeter, A-mode ultrasound and non-contact tonometer, respectively. Corneal curvature(CC, anterior chamber depth(ACDand white-to-white distance(WWDwere measured by Orbscan II. Three dimensional frequency domain coherent optical tomography(3D-OCTwas used to examine the retinal nerve fiber layer thickness(RNFLT. The Pearson correlation coefficient(rand multiple regression analysis were performed to evaluate the relationship between AL, age and ocular parameters.RESULTS: The average AL was 24.15±1.26mm. With elongation of the AL, spherical equivalent(SE(r=-0.742,Pr=-0.395, Pr=-0.374, Pr=0.411, Pr=0.099, P=0.060and WWD(r=0.061, P=0.252. There was also a significant correlation between AL and age(P=0.001, SE(PPPCONCLUSION: In longer eyes, there is a tendency toward myopia, a flatter cornea, a deeper ACD and a thinner RNFLT. Age is an influencing factor for the AL as well.

  3. Nucleon axial coupling from Lattice QCD

    Science.gov (United States)

    Cheng Chang, Chia; Nicholson, Amy; Rinaldi, Enrico; Berkowitz, Evan; Garron, Nicolas; Brantley, David; Monge-Camacho, Henry; Monahan, Chris; Bouchard, Chris; Clark, M. A.; Joó, Bálint; Kurth, Thorsten; Orginos, Kostas; Vranas, Pavlos; Walker-Loud, André

    2018-03-01

    We present state-of-the-art results from a lattice QCD calculation of the nucleon axial coupling, gA, using Möbius Domain-Wall fermions solved on the dynamical Nf = 2 + 1 + 1 HISQ ensembles after they are smeared using the gradient-flow algorithm. Relevant three-point correlation functions are calculated using a method inspired by the Feynman-Hellmann theorem, and demonstrate significant improvement in signal for fixed stochastic samples. The calculation is performed at five pion masses of mπ {400, 350, 310, 220, 130} MeV, three lattice spacings of a {0.15, 0.12, 0.09} fm, and we do a dedicated volume study with mπL {3.22, 4.29, 5.36}. Control over all relevant sources of systematic uncertainty are demonstrated and quantified. We achieve a preliminary value of gA = 1.285(17), with a relative uncertainty of 1.33%.

  4. Axial sheath dynamics in a plasma focus

    International Nuclear Information System (INIS)

    Soliman, H.M.; El-Khalafawy, T.A.; Masoud, M.M.

    1990-01-01

    This paper presents the result of investigation with a 10 kJ Mather type plasma focus. It is operated in hydrogen gas at ambient pressure of 0.15--1 torr and charging voltage of 8--11 kV. Radial distribution of the current sheath density with axial distance has been estimated. Plasma rotation in the expansion chamber in the absence of external magnetic field has been detected. A plasma flare from the plasma focus region propagating in the radial direction has been observed. Streak photography shows two plasma streams flowing simultaneously out of the muzzle. The mean energy of the electron beam ejected from the pinch region of the focused plasma, was measured by retarding field analyzer to be 0.32 keV. The electron temperature of the plasma focus at peak compression was determined by measuring the X-ray intensity as a function of absorber thickness at a distance of 62 cm from the focus. The electron temperature has been found to 3 keV

  5. Compression, heating and fusion in dynamic pinches stabilized by an axial magnetic field

    International Nuclear Information System (INIS)

    Libermann, M.A.; Golberg, S.M.; Velikovich, A.L.

    1990-01-01

    The inertial confinement Z-pinch fusion systems have at least one advantage: there is no limitation on I like I PB , the current can be as high as the pulsed power driver is capable to deliver. When a dynamic Z-pinch is treated as an ICF system, its most important characteristic is stability of compression. The idea of combining the advantages of inertial and magnetic approaches to controlled fusion in some hybrid scheme has been discussed for a long time. It was shown that a sufficiently strong magnetic field in the ICF systems can localize the ignition by suppressing the electron thermal conductivity and diffusion of the α-particles, and also provide an initial preheating of the compressed plasma. It was also pointed out that perhaps the most important is the possibility to inhibit the development of hydrodynamic instabilities in the course of compression with the aid of the magnetic field, thus increasing the degree of stable radial compression. It was shown, that a relatively small axial magnetic field can significantly improve the uniform radial compression by suppressing the most dangerous sausage and kink modes of RT instability associated with inward acceleration of an annular plasma by the azimuthal magnetic field. This allows one to obtain higher degrees of stable radial compression up to 22-fold compression achieved instead of convetnional -8. The stabilizing effect of axial magnetic field on pinch implosions can be explained with the aid of an ideal MHD model. Stability of an implosion can be expected if the final number of e-folding of the dominating perturbation modes n ef is shown to be small or, at least, limited in comparison with the case when no axial magnetic field is present. (author) 9 refs., 1 fig

  6. Numerical analysis of highly deformable elastoplastic beams

    Directory of Open Access Journals (Sweden)

    João Paulo Pascon

    Full Text Available AbstractThe objective of the present study is to develop a numerical formulation to predict the behavior of highly deformable elastoplastic thin beams. Following the Euler-Bernoulli bending, the axial and shear effects are neglected, and the nonlinear second-order differential equation regarding the angle of rotation is defined based on the specific moment-curvature relationship. Although the formulation can be used for general materials, three constitutive models are employed: linear-elastic, bilinear elastoplastic, and linear-elastic with Swift isotropic hardening. The resultant boundary value problem is solved by means of the fourth-order Runge-Kutta integration procedure and the one-parameter nonlinear shooting method. The performance of the present formulation is investigated via three numerical problems involving finite bending of slender beams composed of elastoplastic materials. For these problems, numerical solutions regarding rotations, displacements and strains for the loading, unloading and reloading phases are provided. Finally, it is shown that the present methodology can also be used to determine the post-buckling behavior of elastoplastic thin beams.

  7. Modeling and Simulation of Grasping of Deformable Objects

    DEFF Research Database (Denmark)

    Fugl, Andreas Rune

    . The purpose of this thesis is to address the modeling and simulation of deformable objects, as applied to robotic grasping and manipulation. The main contributions of this work are: An evaluation of 3D linear elasticity used for robot grasping as implemented by a Finite Difference Method supporting regular...... and adaptively refined grids, a stable and accurate non-linear 2D beam model supporting large deformations and difficult boundary effects, a method for the estimation of material properties and pose from depth and colour images, a method for the learning of Peg-in-Hole actions, an outline for Laying-Down actions...... as well a throughout evaluation of the accuracy of models under large deformations....

  8. Deformation-Based Atrophy Estimation for Alzheimer’s Disease

    DEFF Research Database (Denmark)

    Pai, Akshay Sadananda Uppinakudru

    Alzheimer’s disease (AD) - the most common form of dementia, is a term used for accelerated memory loss and cognitive abilities enough to severely hamper day-to-day activities. One of the most globally accepted markers for AD is atrophy, in mainly the brain parenchyma. The goal of the PhD project...... is to develop a deformation-based atrophy estimation pipeline that is reliable and stable. We investigate the application of image registration using freeform deformation and stationary velocity fields in atrophy estimation. In the process, we propose a new multi-scale model for the transformation model...... and a new way to estimate atrophy from a deformation field. We demonstrate the performance of the proposed solution but applying it on the publicly available Alzheimer’s disease neuroimaging data (ADNI) initiative and compare to existing state-of-art atrophy estimation methods....

  9. Fraktalnist deformational relief polycrystalline aluminum

    Directory of Open Access Journals (Sweden)

    М.В. Карускевич

    2006-02-01

    Full Text Available  The possibility of the fractal geometry method application for the analisys of surface deformation structures under cyclic loading is presented.It is shown, that deformation relief of the alclad aluminium alloyes meets the criteria of the fractality. For the fractal demention estimation the method of  “box-counting”can be applied.

  10. Plastic Deformation of Metal Surfaces

    DEFF Research Database (Denmark)

    Hansen, Niels; Zhang, Xiaodan; Huang, Xiaoxu

    2013-01-01

    Plastic deformation of metal surfaces by sliding and abrasion between moving parts can be detrimental. However, when the plastic deformation is controlled for example by applying different peening techniques hard surfaces can be produced which can increase the fracture resistance and fatigue life...

  11. A nonlinear analytical model for the squeeze-film dynamics of parallel plates subjected to axial flow

    International Nuclear Information System (INIS)

    Piteau, Ph.; Antunes, J.

    2010-01-01

    In this paper, we develop a theoretical model to predict the nonlinear fluid-structure interaction forces and the dynamics of parallel vibrating plates subjected to an axial gap flow. The gap is assumed small, when compared to the plate dimensions, the plate width being much larger than the length, so that the simplifying assumptions of 1D bulk-flow models are adequate. We thus develop a simplified theoretical squeeze-film formulation, which includes both the distributed and singular dissipative flow terms. This model is suitable for performing effective time-domain numerical simulations of vibrating systems which are coupled by the nonlinear unsteady flow forces, for instance the vibro-impact dynamics of plates with fluid gap interfaces. A linearized version of the flow model is also presented and discussed, which is appropriate for studying the complex modes and linear stability of flow/structure coupled systems as a function of the average axial gap velocity. Two applications of our formulation are presented: (1) first we study how an axial flow modifies the rigid-body motion of immersed plates falling under gravity; (2) then we compute the dynamical behavior of an immersed oscillating plate as a function of the axial gap flow velocity. Linear stability plots of oscillating plates are shown, as a function of the average fluid gap and of the axial flow velocity, for various scenarios of the loss terms. These results highlight the conditions leading to either the divergence or flutter instabilities. Numerical simulations of the nonlinear flow/structure dynamical responses are also presented, for both stable and unstable regimes. This work is of interest to a large body of real-life problems, for instance the dynamics of nuclear spent fuel racks immersed in a pool when subjected to seismic excitations, or the self-excited vibro-impact motions of valve-like components under axial flows. (authors)

  12. Effect of Multi-Axial Loading on Residual Strain Tensor for 12L14 Steel Alloy

    Science.gov (United States)

    Bunn, Jeffrey R.; Penumadu, Dayakar; Lou, Xin; Hubbard, Camden R.

    2014-08-01

    Evaluating the state of residual strain or stress is critically important for structural materials and for reliable design of complex shape components that need to function in extreme environment subjected to large thermo-mechanical loading. When residual stress state is superposed to external loads, it can lead to reduction or increase in failure strength. Past diffraction studies for evaluating the residual strain state involved measuring lattice spacings in three orthogonal directions and do not often correspond to principal directions. To completely resolve the state of strain at a given location, a full strain tensor must be determined. This is especially important when characterizing materials or metallic components exposed to biaxial or complex loading. Neutron diffraction at the second Generation Neutron Residual Stress Facility (NRSF2) at Oak Ridge National Laboratory is used in this study to measure strain tensors associated with different modes of stress path. Hollow cylinder steel samples with 2 mm wall thickness are subjected to either pure axial extension or pure torsion to simulate multi-axial loading conditions. A virgin sample that is not subjected to any deformation, but subjected to identical manufacturing conditions and machining steps involved to obtain hollow cylinder geometry is used for obtaining reference d-spacing for given hkl planes at target spatial location(s). The two samples which are subjected to either pure tension or torsion are loaded to a deformation state that corresponded to equal amount of octahedral shear strain which is an invariant. This procedure is used so that a basis for comparison between the two samples can be made to isolate the stress path effects. A 2-circle Huber orienteer is used to obtain strain measurements on identical gauge volume at a series of φ and ψ values. The residual state of stress tensor corresponding to ex situ (upon unloading) conditions is presented for three lattice planes (211, 110, 200) for

  13. Possible interplay between non-axial and hexadecapole degrees of freedom. An explanation for ''enormously'' large Q4

    International Nuclear Information System (INIS)

    Dudek, J.; Nazarewicz, W.; Rozmej, P.

    1980-02-01

    The theoretical calculations of equilibrium deformations and multipole moments of rare earth nuclei are presented. The good agreement with experiment for Gd, Dy, Er, Yb nuclei is found in contrast to large discrepancies for heavy Hf, W and Os isotopes, especially connected with hexadecapole deformations and moments. Possibilities of the explanation of the above hexadecapole anomaly are discussed. The assumption of the ''partial-bubble''-like density distribution, suggested from electron scattering measurements, is found to be quite insufficient for the hexadecapole anomaly explanation. The simultaneous inclusion of non-axial and hexadecapole degrees of freedom is found to be the most promising approach to explain the ''hexadecapole anomaly'' for Hf, W, Os isotopes. (author)

  14. Nuclear deformation at finite temperature.

    Science.gov (United States)

    Alhassid, Y; Gilbreth, C N; Bertsch, G F

    2014-12-31

    Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte Carlo method is used to generate a statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to temperatures higher than the spherical-to-deformed shape phase-transition temperature of mean-field theory.

  15. Nuclear Deformation at Finite Temperature

    Science.gov (United States)

    Alhassid, Y.; Gilbreth, C. N.; Bertsch, G. F.

    2014-12-01

    Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte Carlo method is used to generate a statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to temperatures higher than the spherical-to-deformed shape phase-transition temperature of mean-field theory.

  16. Deformation of Man Made Objects

    KAUST Repository

    Ibrahim, Mohamed

    2012-07-01

    We introduce a framework for 3D object deformation with primary focus on man-made objects. Our framework enables a user to deform a model while preserving its defining characteristics. Moreover, our framework enables a user to set constraints on a model to keep its most significant features intact after the deformation process. Our framework supports a semi-automatic constraint setting environment, where some constraints could be automatically set by the framework while others are left for the user to specify. Our framework has several advantages over some state of the art deformation techniques in that it enables a user to add new features to the deformed model while keeping its general look similar to the input model. In addition, our framework enables the rotation and extrusion of different parts of a model.

  17. Vibration Characteristics of Axially Moving Titanium- Polymer Nanocomposite Faced Sandwich Plate Under Initial Tension

    Directory of Open Access Journals (Sweden)

    Ali Ghorbanpour Arani

    2017-07-01

    Full Text Available In the present research, vibration and instability of axially moving sandwich plate made of soft core and composite face sheets under initial tension is investigated. Single-walled carbon nano-tubes (SWCNTs are selected as a reinforcement of composite face sheets inside Poly methyl methacrylate (PMMA matrix. Higher order shear deformation theory (HSDT is utilized due to its accuracy of polynomial functions than other plate theories. Based on extended rule of mixture, the structural properties of composite face sheets are taken into consideration. Motion equations are obtained by means of Hamilton’s principle and solved analytically. Influences of various parameters such as axially moving speed, volume fraction of CNTs, pre-tension, thickness and aspect ratio of sandwich plate on the vibration characteristics of moving system are discussed in details. The results indicated that the critical speed of moving sandwich plate is strongly dependent on the volume fraction of CNTs. Therefore, the critical speed of moving sandwich plate can be improved by adding appropriate values of CNTs. The results of this investigation can be used in design and manufacturing of marine vessels and aircrafts.

  18. Stable isotope analysis

    International Nuclear Information System (INIS)

    Tibari, Elghali; Taous, Fouad; Marah, Hamid

    2014-01-01

    This report presents results related to stable isotopes analysis carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 127 samples. These results demonstrate that Oxygen-18 and Deuterium in water analysis were performed by infrared Laser spectroscopy using a LGR / DLT-100 with Autosampler. Also, the results are expressed in δ values (‰) relative to V-SMOW to ± 0.3 ‰ for oxygen-18 and ± 1 ‰ for deuterium.

  19. Surgical-orthodontic correction of a Class III dentofacial deformity

    Directory of Open Access Journals (Sweden)

    Raghu Devanna

    2010-01-01

    Full Text Available This case report describes the surgical-orthodontic treatment of a 26-year-old post-pubertal male patient with a Class III dentofacial deformity. In the pre-surgical orthodontic phase of treatment, a reverse overjet of 5.5 mm was created and arch compatibility was obtained. A mandibualr set back with BSSO was performed during surgery to restore ideal overjet, overbite, occlusion and optimal esthetics. After 1 year of treatment, the results remained stable.

  20. Conservative axial burnup distributions for actinide-only burnup credit

    International Nuclear Information System (INIS)

    Kang, C.; Lancaster, D.

    1997-11-01

    Unlike the fresh fuel approach, which assumes the initial isotopic compositions for criticality analyses, any burnup credit methodology must address the proper treatment of axial burnup distributions. A straightforward way of treating a given axial burnup distribution is to segment the fuel assembly into multiple meshes and to model each burnup mesh with the corresponding isotopic compositions. Although this approach represents a significant increase in modeling efforts compared to the uniform average burnup approach, it can adequately determine the reactivity effect of the axial burnup distribution. A major consideration is what axial burnup distributions are appropriate for use in light of many possible distributions depending on core operating conditions and histories. This paper summarizes criticality analyses performed to determine conservative axial burnup distributions. The conservative axial burnup distributions presented in this paper are included in the Topical Report on Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel Packages, Revision 1 submitted in May 1997 by the US Department of Energy (DOE) to the US Nuclear Regulatory Commission (NRC). When approved by NRC, the conservative axial burnup distributions may be used to model PWR spent nuclear fuel for the purpose of gaining actinide only burnup credit

  1. Forensic Stable Isotope Biogeochemistry

    Science.gov (United States)

    Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

    2016-06-01

    Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  2. Dispositivos de asistencia ventricular de tipo axial

    Directory of Open Access Journals (Sweden)

    Albert Miralles Cassina

    2009-04-01

    Full Text Available El uso de dispositivos de asistencia ventricular se ha ido extendiendo en las últimas décadas. La mejora de los resultados ha ido acompañada del diseño de nuevos aparatos más pequeños y eficientes como son las bombas de flujo axial. las características técnicas básicas de estos dispositivos se hallan en la generación de un flujo continuo unidireccional conseguido mediante sistemas de turbina que obtienen su alimentación de una fuente eléctrica. Las ventajas principales de estos dispositivos son: su facilidad de implantación por su tamaño reducido, su prolongada durabilidad gracias a su sencillo diseño y su eficiencia energética al utilizar energía eléctrica. Su utilidad se ha podido demostrar en diferentes indicaciones de asistencia circulatoria mecánica, como en el caso de puente al trasplante o dispositivo de recuperación miocárdica, si bien donde radica más interés es en su uso como sistemas de asistencia circulatoria mecánica definitiva. Existe una variedad de modelos de diversos diseños. Son dispositivos que permiten soporte normalmente univentricular izquierdo, que se implantan en el tórax con cánula de entrada a nivel ventricular y cánula de salida a nivel aórtico. En este artículo se efectúa una descripción de los principales sistemas disponibles en la actualidad, comentando las características técnicas, ventajas e inconvenientes y un resumen de la experiencia existente.

  3. Radial loads and axial thrusts on centrifugal pumps

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The proceedings of a seminar organised by the Power Industries Division of the IMechE are presented in this text. Complete contents: Review of parameters influencing hydraulic forces on centrifugal impellers; The effect of fluid forces at various operation conditions on the vibrations of vertical turbine pumps; A review of the pump rotor axial equilibrium problem - some case studies; Dynamic hydraulic loading on a centrifugal pump impeller; Experimental research on axial thrust loads of double suction centrifugal pumps; A comparison of pressure distribution and radial loads on centrifugal pumps; A theoretical and experimental investigation of axial thrusts within a multi-stage centrifugal pump

  4. Measurement for cobalt target activity and its axial distribution

    International Nuclear Information System (INIS)

    Li Xingyuan; Chen Zigen.

    1985-01-01

    Cobalt target activity and its axial distribution are measured in process of producing radioactive isotopes 60 Co by irradiation in HFETR. Cobalt target activity is obtained with measured data at 3.60 m and 4.60 m, relative axial distribution of cobalt target activity is obtained with one at 30 cm, and axial distribution of cobalt target activity(or specific activity) is obtained with both of data. The difference between this specific activity and measured result for 60 Co teletherapy sources in the end is less than +- 5%

  5. Axial weak currents in the Wess-Zumino term

    International Nuclear Information System (INIS)

    Fujikawa, Kazuo.

    1985-03-01

    The conventional axial gauging of the Wess-Zumino term leads to the results which do not necessarily agree with the expectations on the basis of quark level Ward-Takahashi identities. This discrepancy arises from the fact that the quark level anomalous identities reflect the short distance structure of QCD, whereas the gauging of the Wess-Zumino term reflects the axial symmetry in the spontaneously broken chiral phase. The low energy theorem for axial weak fields is not sharply defined, in contrast to the case of vector fields where no such complications arise. (author)

  6. The Design Method of Axial Flow Runners Focusing on Axial Flow Velocity Uniformization and Its Application to an Ultra-Small Axial Flow Hydraulic Turbine

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nishi

    2016-01-01

    Full Text Available We proposed a portable and ultra-small axial flow hydraulic turbine that can generate electric power comparatively easily using the low head of open channels such as existing pipe conduits or small rivers. In addition, we proposed a simple design method for axial flow runners in combination with the conventional one-dimensional design method and the design method of axial flow velocity uniformization, with the support of three-dimensional flow analysis. Applying our design method to the runner of an ultra-small axial flow hydraulic turbine, the performance and internal flow of the designed runner were investigated using CFD analysis and experiment (performance test and PIV measurement. As a result, the runners designed with our design method were significantly improved in turbine efficiency compared to the original runner. Specifically, in the experiment, a new design of the runner achieved a turbine efficiency of 0.768. This reason was that the axial component of absolute velocity of the new design of the runner was relatively uniform at the runner outlet in comparison with that of the original runner, and as a result, the negative rotational flow was improved. Thus, the validity of our design method has been verified.

  7. Supersymmetric q-deformed quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Traikia, M. H.; Mebarki, N. [Laboratoire de Physique Mathematique et Subatomique, Mentouri University, Constantine (Algeria)

    2012-06-27

    A supersymmetric q-deformed quantum mechanics is studied in the weak deformation approximation of the Weyl-Heisenberg algebra. The corresponding supersymmetric q-deformed hamiltonians and charges are constructed explicitly.

  8. On infinitesimal conformai deformations of surfaces

    Directory of Open Access Journals (Sweden)

    Юлия Степановна Федченко

    2014-11-01

    Full Text Available A new form of basic equations for conformai deformations is found. The equations involve tensor fields of displacement vector only. Conditions for trivial deformations as well as infinitesimal conformai deformations are studied.

  9. The Nonradiographic Axial Spondyloarthritis, the Radiographic Axial Spondyloarthritis, and Ankylosing Spondylitis: The Tangled Skein of Rheumatology

    Science.gov (United States)

    Rawat, Roopa; Agrawal, Neha; Patil, Nilesh S.

    2017-01-01

    Since 1984 the diagnosis of ankylosing spondylitis (AS) has been based upon the modified New York (mNY) criteria with mandatory presence of radiographic sacroiliitis, without which the diagnosis is not tenable. However, it may take years or decades for radiographic sacroiliitis to develop delaying the diagnosis for long periods. It did not matter in the past because no effective treatment was available. However, with the availability of a highly effective treatment, namely, tumour necrosis factor-α inhibitors (TNFi), the issue of early diagnosis of AS acquired an urgency. The Assessment of SpondyloArthritis International Society (ASAS) classification criteria published in 2009 was a significant step towards this goal. These criteria described an early stage of the disease where sacroiliitis was demonstrable only on MRI but not on standard radiograph. Therefore, this stage of the disease was labelled “nonradiographic axial SpA” (nr-axSpA). But questions have been raised if, in search of early diagnosis, specificity was compromised. The Federal Drug Administration (FDA, USA) withheld approval for the use of TNFi in patients with nr-axSpA because of issues related to the specificity of these criteria. This review attempts to clarify some of these aspects of the nr-axSpA-AS relationship and also tries to answer the question whether ASAS classifiable radiographic axial spondyloarthritis (r-axSpA) term can be interchangeably used with the term AS. PMID:28555158

  10. Computer simulation of plastic deformation in irradiated metals

    International Nuclear Information System (INIS)

    Colak, U.

    1989-01-01

    A computer-based model is developed for the localized plastic deformation in irradiated metals by dislocation channeling, and it is applied to irradiated single crystals of niobium. In the model, the concentrated plastic deformation in the dislocation channels is postulated to occur by virtue of the motion of dislocations in a series of pile-tips on closely spaced parallel slip planes. The dynamics of this dislocation motion is governed by an experimentally determined dependence of dislocation velocity on shear stress. This leads to a set of coupled differential equations for the positions of the individual dislocations in the pile-up as a function of time. Shear displacement in the channel region is calculated from the total distance traveled by the dislocations. The macroscopic shape change in single crystal metal sheet samples is determined by the axial displacement produced by the shear displacements in the dislocation channels. Computer simulations are performed for the plastic deformation up to 20% engineering strain at a constant strain rate. Results of the computer calculations are compared with experimental observations of the shear stress-engineering strain curve obtained in tensile tests described in the literature. Agreement between the calculated and experimental stress-strain curves is obtained for shear displacement of 1.20-1.25 μm and 1000 active slip planes per channel, which is reasonable in the view of experimental observations

  11. Spacetimes for λ-deformations

    Energy Technology Data Exchange (ETDEWEB)

    Sfetsos, Konstadinos [Department of Nuclear and Particle Physics, Faculty of Physics, University of Athens,Athens 15784 (Greece); Thompson, Daniel C. [Theoretische Natuurkunde, Vrije Universiteit Brussel andThe International Solvay Institutes,Pleinlaan 2, B-1050, Brussels (Belgium)

    2014-12-29

    We examine a recently proposed class of integrable deformations to two-dimensional conformal field theories. These λ-deformations interpolate between a WZW model and the non-Abelian T-dual of a Principal Chiral Model on a group G or, between a G/H gauged WZW model and the non-Abelian T-dual of the geometric coset G/H. λ-deformations have been conjectured to represent quantum group q-deformations for the case where the deformation parameter is a root of unity. In this work we show how such deformations can be given an embedding as full string backgrounds whose target spaces satisfy the equations of type-II supergravity. One illustrative example is a deformation of the Sl(2,ℝ)/U(1) black-hole CFT. A further example interpolates between the ((SU(2)×SU(2))/(SU(2)))×((SL(2,ℝ)×SL(2,ℝ))/(SL(2,ℝ)))×U(1){sup 4} gauged WZW model and the non-Abelian T-dual of AdS{sub 3}×S{sup 3}×T{sup 4} supported with Ramond flux.

  12. Design and fabrication of tri-axial capillary needles in flow focusing for microencapsulation of multiple drugs and imaging agents

    Science.gov (United States)

    Si, Ting; Feng, Hanxin; Xie, Bin; Xu, Ronald

    2014-03-01

    Microencapsulation of multiple drugs and imaging agents is significant for various biomedical applications. In this work we describe a novel method based on flow focusing geometry using tri-axial metallic capillary needles manufactured by a laser beam welding process. The tri-axial needle can be readily cleaned, assembled, and aligned. With this needle assembly, we develop a tri-axial capillary flow focusing device in which different combinations of liquids are focused in the core of a high-speed gas stream coflowing through a small orifice. Under appropriate working conditions, stable cone-jet configurations with three layers of liquids in an external gas stream can be obtained, resulting in multilayered microparticles with outer shell, middle layer, and inner core. The new design of tri-axial needles enables reliable encapsulation of multiple drugs and imaging agents in biodegradable microcapsules with the enhanced size distribution, increased productivity, and improved drug-loading efficiency. Furthermore, in this method the outer and the middle shell fluids can be released to produce monodisperse microparticles at smaller scales which have potential applications in multi-modal imaging, drug delivery, material processing and biomedicine.

  13. Deformation behavior of vanadium alloys containing hydrogen at constant stress

    International Nuclear Information System (INIS)

    Jiming Chen; Hui Cong; Yong Chen; Cong Li; Shaoyu Qiu

    2006-01-01

    Vanadium alloy, one of the candidates for next fusion reactors as structural materials, has the issue of mechanical property degradation by hydrogen absorption. In the present paper, V-4Cr-4Ti and an alternative V-6W-2.5Ti were studied for their tensile deformation behaviors at room temperature under constant load. The alloys contained 33-341 wppm H by a previous exposure in hydrogen gas at 500-800 o C for hours. Results showed hydrogen release during the tensile loading, which caused shrinkage of the specimens and the increase of elastic modulus and the decrease of tensile strength. Tensile holding the specimen at stress higher than yield strength led to a three-stage deformation behavior, similar to the traditional thermal creep but show stable deformation in the 3 rd stage. The steady deformation rate in this stage is much higher than that in the 2 nd one, and it increased with increasing hold stress and the increase of the hydrogen concentration. As the test temperature is fairly low, the deformation should be dislocation glide assisted and could be enhanced by hydrogen release. Hydrogen absorption and hydrogen release would bring about an issue of dimensional instability of structural components, which should be taken into account in the design. (author)

  14. Deformation mechanisms of D022 ordered intermetallic phase in superalloys

    International Nuclear Information System (INIS)

    Lv, D.C.; McAllister, D.; Mills, M.J.; Wang, Y.

    2016-01-01

    High-temperature alloys in general and superalloys in particular are strengthened by ordered intermetallic phases that are relatively stable at elevated temperatures. Because of their low symmetry, however, these ordered intermetallic phases have rather complicated deformation mechanisms that are difficult to uncover by experiment alone. In this study we use a combination of ab initio calculation and phase field simulation at the elementary defect level to illustrate how dislocations interact with precipitates of an ordered intermetallic phase, γ″ (D0 22 , tetragonal), the primary strengthening phase in Ni-Nb-Fe-Cr-Ti-Al-Mo alloy (Inconel 718 or IN718 superalloy). A rich variety of new and sophisticated deformation mechanisms are discovered, including a novel mechanism of dislocation generation (accompanied by a spontaneous stacking fault (SF) transition), formation of superlattice intrinsic SF ribbons (SISF-ribbons) and 1/3<112>-type compact super-dislocations, along with ISF shearing and Orowan looping. The predicted deformation microstructures seem to agree with recent electron microscopy observations in IN718. The detailed deformation mechanisms uncovered can be incorporated in constitutive microstructure-property relationships for advanced crystal plasticity modeling and the approach developed can be used to study plastic deformation of other intermetallic phases in different alloy systems.

  15. Deforming tachyon kinks and tachyon potentials

    International Nuclear Information System (INIS)

    Afonso, Victor I.; Bazeia, Dionisio; Brito, Francisco A.

    2006-01-01

    In this paper we investigate deformation of tachyon potentials and tachyon kink solutions. We consider the deformation of a DBI type action with gauge and tachyon fields living on D1-brane and D3-brane world-volume. We deform tachyon potentials to get other consistent tachyon potentials by using properly a deformation function depending on the gauge field components. Resolutions of singular tachyon kinks via deformation and applications of deformed tachyon potentials to scalar cosmology scenario are discussed

  16. Voluminous lava flow from Axial Seamount's south rift constrains extension rate on northern Vance Segment

    Science.gov (United States)

    Le Saout, M.; Clague, D. A.; Paduan, J. B.

    2017-12-01

    Axial Seamount is characterized by a robust magma supply resulting from the interaction between the Cobb hotspot and the Juan de Fuca Ridge. During the last two decades, magmatic activity was focused within the summit caldera and upper and middle portions of the two rift zones, with eruptions in 1998, 2011, and 2015. However, the distal ends of both rift zones have experienced numerous eruptions in the past. The most voluminous flows are located near the extreme ends, greater than 40 kilometers from the caldera. Where Axial's South Rift Zone overlaps with the Vance Segment of the Juan de Fuca Ridge, the 2015 MBARI expedition mapped 16 km2 of the seafloor with our AUV, and collected 33 rocks and 33 sediment cores during two ROV dives. The data were used to confirm the boundaries of an extensive flow tentatively identified using modern ship based bathymetry. This flow is 18 km wide and 6 km long for a total surface area of 63 km2. The flow is modified by superficial ( 5 m deep) and deep (25 to 45 m deep) subsidence pits, with the deepest pits giving an indication of the minimum thickness of the flow. The maximum thickness of 100 m is measured at the margins of the flow. We thus estimate a volume between 2.5 and 6 km3, making this flow the most voluminous known on the global mid ocean ridge system. The minimum volume is equivalent to the present volume of the summit caldera. Radiocarbon ages of foraminifera from the basal sections of sediment cores suggest that this flow is 1000 years old. This flow travelled east and partially filled the axial valley of the adjacent Vance Segment. Since emplacement, this part of the flow has experienced deformation by fissures and faults aligned with the trend of the Vance Segment. The horizontal extension across these features allows us to estimate a local deformation rate of 3 cm/yr of tectonic extension on the northern end of Vance Segment during the last 1000 years.

  17. Geomorphological impact of an axial-flow hydrokinetic turbine model

    Science.gov (United States)

    Hill, C.; Chamorro, L. P.; Sotiropoulos, F.; Guala, M.

    2012-12-01

    MHK devices in river or tidal environments are expected to impact the local geomorphology in the short and long terms, yet to what extent is unknown. A series of experiments in the SAFL main channel were performed on an erodible sediment layer at the threshold of motion aimed at quantifying the local effect of an axial-flow turbine model on erosional and depositional processes. Full planimetric, time resolved measurements of bed elevations z = z(x, y, t) were obtained using a 2D sheet laser scanner mounted on a computer controlled data acquisition carriage. Measurement resolution was 2 mm x 2 mm in the streamwise (x) and spanwise (y) directions, and approximately 70 s temporally. Approximately 180 topographic scans were obtained in about 3.8 hours while simultaneously monitoring mean approach velocities using an acoustic Doppler profiler located approximately 2 rotor diameters, dT, upstream of the turbine. Three synchronized acoustic Doppler velocimeters (ADVs) located 6dT downstream of the turbine at locations coincident with the turbine axis of symmetry and at the lateral blade tips at hub height obtained instantaneous three component velocity measurements u, v, w in the wake of the turbine. The 1:10 scale axial-flow hydrokinetic turbine model operated at a constant tip speed ratio ωdT/2U = 6.3 while measuring instantaneous torque (ω is the rotor angular velocity and U is the mean incoming velocity at the hub height). The sediment layer consisted of coarse sand with mean diameter d50 = 1.8 mm. Using laser scanning measurements, the sediment layer was observed to be stable under the given hydraulic conditions (total discharge of Qw = 1.765 m3s-1 and water depth of h = 1.15 m) during the baseline case (no turbine), ensuring that the mean shear stress was below the critical value for the duration of the experiment. Maintaining the same flow conditions, three additional experiments were performed: a) effect of turbine support (base and tower) only, b) effect of

  18. The relation between anomalous magnetic moment and axial anomaly

    International Nuclear Information System (INIS)

    Teryaev, O.V.

    1990-12-01

    The conservation of total angular momentum of spinor particle leads to a simple relation between the famous Schwinger and Adler coefficients determining axial anomaly and anomalous magnetic moment, respectively. (author). 8 refs, 1 fig

  19. Defining active sacroiliitis on MRI for classification of axial spondyloarthritis

    DEFF Research Database (Denmark)

    Lambert, Robert G W; Bakker, Pauline A C; van der Heijde, Désirée

    2016-01-01

    OBJECTIVES: To review and update the existing definition of a positive MRI for classification of axial spondyloarthritis (SpA). METHODS: The Assessment in SpondyloArthritis International Society (ASAS) MRI working group conducted a consensus exercise to review the definition of a positive MRI...... for inclusion in the ASAS classification criteria of axial SpA. Existing definitions and new data relevant to the MRI diagnosis and classification of sacroiliitis and spondylitis in axial SpA, published since the ASAS definition first appeared in print in 2009, were reviewed and discussed. The precise wording....... CONCLUSION: The definition of a positive MRI for classification of axial SpA should continue to primarily depend on the imaging features of 'active sacroiliitis' until more data are available regarding MRI features of structural damage in the sacroiliac joint and MRI features in the spine and their utility...

  20. The geometrical theory of diffraction for axially symmetric reflectors

    DEFF Research Database (Denmark)

    Rusch, W.; Sørensen, O.

    1975-01-01

    The geometrical theory of diffraction (GTD) (cf. [1], for example) may be applied advantageously to many axially symmetric reflector antenna geometries. The material in this communication presents analytical, computational, and experimental results for commonly encountered reflector geometries...

  1. Time Domain Terahertz Axial Computed Tomography Non Destructive Evaluation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to demonstrate key elements of feasibility for a high speed automated time domain terahertz computed axial tomography (TD-THz CT) non destructive...

  2. Image quality and radiation exposure with prospectively ECG-triggered axial scanning for coronary CT angiography: the multicenter, multivendor, randomized PROTECTION-III study.

    Science.gov (United States)

    Hausleiter, Jörg; Meyer, Tanja S; Martuscelli, Eugenio; Spagnolo, Pietro; Yamamoto, Hiroaki; Carrascosa, Patricia; Anger, Thomas; Lehmkuhl, Lukas; Alkadhi, Hatem; Martinoff, Stefan; Hadamitzky, Martin; Hein, Franziska; Bischoff, Bernhard; Kuse, Miriam; Schömig, Albert; Achenbach, Stephan

    2012-05-01

    The purpose of this study was to evaluate image quality and radiation dose using a prospectively electrocardiogram (ECG)-triggered axial scan protocol compared with standard retrospective ECG-gated helical scanning for coronary computed tomography angiography. Concerns have been raised regarding radiation exposure during coronary computed tomography angiography. Although the use of prospectively ECG-triggered axial scan protocols may effectively lower radiation dose compared with helical scanning, it is unknown whether image quality is maintained in a clinical setting. In a prospective, multicenter, multivendor trial, 400 patients with low and stable heart rates were randomized to either an axial or a helical coronary computed tomography angiography scan protocol. The primary endpoint was to demonstrate noninferiority in image quality with the axial scan protocol, which was assessed on a 4-point scale (1 = nondiagnostic, 4 = excellent image quality). Secondary endpoints included radiation dose and the rate of downstream testing during 30-day follow-up. Image quality in patients scanned with the axial scan protocol (score 3.36 ± 0.59) was not inferior compared with helical scan protocols (3.37 ± 0.59) (p for noninferiority <0.004). Axial scanning was associated with a 69% reduction in radiation exposure (dose-length product [estimated effective dose] 252 ± 147 mGy · cm [3.5 ± 2.1 mSv] vs. 802 ± 419 mGy · cm [11.2 ± 5.9 mSv] for axial vs. helical scan protocols, p < 0.001). The rate of downstream testing did not differ (13.8% vs. 15.9% for axial vs. helical scan protocols, p = 0.555). In patients with stable and low heart rates, the prospectively ECG-triggered axial scan protocol maintained image quality but reduced radiation exposure by 69% compared with helical scanning. Axial computed tomography data acquisition should be strongly recommended in suitable patients to avoid unnecessarily high radiation exposure. Copyright © 2012 American College of

  3. Adjustable static and dynamic actuation of clamped-guided beams using electrothermal axial loads

    KAUST Repository

    Alcheikh, Nouha

    2018-02-14

    The paper presents adjustable static and dynamic actuations of in-plane clamped-guided beams. The structures, of variable stiffness, can be used as highly tunable resonators and actuators. Axial loads are applied through electrothermal U-shaped and flexure beams actuators stacked near the edges of curved (arch) beams. The electrothermal actuators can be configurred in various ways to adjust as desired the mechanical stiffness of the structures; thereby controlling their deformation stroke as actuators and their operating resonance frequency as resonators. The experimental and finite element results demonstrate the flexibility of the designs in terms of static displacements and resonance frequencies of the first and second symmetric modes of the arches. The results show considerable increase in the resonance frequency and deflection of the microbeam upon changing end actuation conditions, which can be promising for low voltage actuation and tunable resonators applications, such as filters and memory devices. As case studies of potential device configurations of the proposed design, we demonstrate eight possibilities of achieving new static and dynamic behaviors, which produce various resonance frequencies and static displacement curves. The ability to actively shift the entire frequency response curve of a device is desirable for several applications to compensate for in-use anchor degradations and deformations. As an example, we experimentally demonstrate using the device as a resonant logic gate, with active resonance tuning, showing fundamental 2-bit logic functions, such as AND,XOR, and NOR.

  4. Pole prescription in axial gauge at finite temperature

    Science.gov (United States)

    Kreuzer, Maximilian; Nachbagauer, Herbert

    1991-11-01

    We establish Yang-Mills theory at finite temperature in axial gauge. We encounter the breakdown of the Hata-Kugo expression for the partition function in the special choice of temporal axial gauge. For n ≠ 0 the finite temperature propagator is calculated in both the imaginary time formalism and the real time formalism. In the latter we recover the Leibbrandt-Mandelstam prescription in the lijit T→0. As a check we calculate the mean energy to lowest order.

  5. Pole prescription in axial gauge at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, M.; Nachbagauer, H. (Technische Univ., Vienna (Austria). Inst. fuer Theoretische Physik)

    1991-11-14

    We establish Yang-Mills theory at finite temperature in axial gauge. We encounter the breakdown of the Hata-Kugo expression for the partition function in the special choice of temporal axial gauge. For n {ne} 0 the finite temperature propagator is calculated in both the imaginary time formalism and the real time formalism. In the latter we recover the Leibbrandt-Mandelstam prescription in the limit T {yields} 0. As a check we calculate the mean energy to lowest order. (orig.).

  6. Axial myopia in computed and magnetic resonance tomography

    Energy Technology Data Exchange (ETDEWEB)

    Beyer-Enke, S.A.; Goerich, J.; Gamroth, A.

    1987-08-01

    The case of a 44-year old woman suffering from amblyopia on the left eye with unilateral proptosis caused by axial (progressive) myopia is presented. The clinical and radiological findings were discussed in reference to the literature. The diagnosis was established by ruling out neoplastic, inflammatory or endocrine causes for the exophtalmos. CT and MR scans revealed an enlarged left globe without evidence of orbital masses. The findings were regarded as typical for the diagnosis at axial myopia.

  7. Flutter of a fan blade in supersonic axial flow

    Science.gov (United States)

    Kielb, Robert E.; Ramsey, John K.

    1988-01-01

    An application of a simple aeroelastic model to an advanced supersonic axial flow fan is presented. Lane's cascade theory is used to determine the unsteady aerodynamic loads. Parametric studies are performed to determine the effects of mode coupling, Mach number, damping, pitching axis location, solidity, stagger angle, and mistuning. The results show that supersonic axial flow fan and compressor blades are susceptible to a strong torsional mode flutter having critical reduced velocities which can be less than one.

  8. Strain localization in carbonate rocks experimentally deformed in the ductile field

    Science.gov (United States)

    Rybacki, E.; Morales, L. F. G.; Dresen, G.

    2012-04-01

    The deformation of rocks in the Earth's crust is often localized, varying from brittle fault gauges in shallow environments to mylonites in ductile shear zones at greater depth. A number of theoretical, experimental, and field studies focused on the evolution and extend of brittle fault zones, but little is known so far about initiation of ductile shear zones. Strain localization in rocks deforming at high temperature and pressure may be induced by several physical, chemical, or structurally-related mechanisms. We performed simple and pure shear deformation experiments on carbonate rocks containing structural inhomogenities in the ductile deformation regime. The results may help to gain insight into the evolution of high temperature shear zones. As starting material we used cylindrical samples of coarse-grained Carrara marble containing one or two 1 mm thin artificially prepared sheets of fine-grained Solnhofen limestone, which act as soft inclusions under the applied experimental conditions. Length and diameter of the investigated solid and hollow cylinders were 10-20 mm and 10-15 mm, respectively. Samples were deformed in a Paterson-type gas deformation apparatus at 900° C temperature and confining pressures of 300 and 400 MPa. Three samples were deformed in axial compression at a bulk strain rate of 8x10-5 s-1to axial strains between 0.02 and 0.21 and 15 samples were twisted in torsion at a bulk shear strain rate of 2x10-4 s-1 to shear strains between 0.01 and 3.74. At low strain, specimens deformed axially and in torsion show minor strain hardening that is replaced by strain weakening at shear strains in excess of about 0.2. Peak shear stress at the imposed condition is about 20 MPa. Strain localized strongly within the weak inclusions as indicated by inhomogeneous bending of initially straight strain markers on sample jackets. Maximum strain concentration within inclusions with respect to the adjacent matrix was between 4 and 40, depending on total strain and

  9. Axial design of nuclear fuel using path relinking; Diseno axial de combustible nuclear utilizando path relinking

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, A.; Torres, M.; Ortiz, J. J.; Perusquia, R.; Hernandez, J. L.; Montes, J. L. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: jacm@nuclear.inin.mx

    2008-07-01

    In the present work the preliminary results were obtained with the zoctli system whose purpose is the axial design of assembly of nuclear fuel under certain considerations. For the mentioned design well-know cells were already used and that they have been proven in diverse cycles of operation in the nuclear power plant of Laguna Verde. The design contemplates fuels assemblies of 10x10 and with 2 water channels. The assembly was distributed in 6 axial zones according to its structure. In order to take to end the optimization is was used the well-known technique like Path relinking and to find the group of previous solutions required by this technique uses the technical Taboo search. In order to work with Path relinking, 5 trajectories was taken in to account from a set of 5 previous solutions generated with theTaboo search, the update of the group of solutions is carried out in dynamic form. In the case of the Taboo search it was used a list of variable size, it was implement an aspiration approach, it was used the vector of frequencies and due to the cost of the evaluation of the objective function, only it was review 5% of the vicinity. For the objective function was considered the limit thermal, the axial profile of power, the effective multiplication factor and the margin of having turned off in cold. In order to prove the design system, it was used a balance cycle with a value of reference of 0.9928 for the effective multiplication factor that is equivalent to a produced energy of 10896 MWd/TU at the end of operation to full power. The designed assemblies were placed both in one of lots different from fresh assemblies on which it counts the referred cycle. At the end one a comparison with the results obtained with other techniques and under similar conditions is made. The results obtained until the moment show an appropriate performance of the system. It is possible to indicate that a small inconvenient is the amount of consumed resources of calculation during

  10. Behaviour of partially composite precast concrete sandwich panels under flexural and axial loads

    Science.gov (United States)

    Tomlinson, Douglas George

    Precast concrete sandwich panels are commonly used on building exteriors. They are typically composed of two concrete wythes that surround rigid insulation. They are advantageous as they provide both structural and thermal resistance. The structural response of sandwich panels is heavily influenced by shear connectors that link the wythes together. This thesis presents a study on partially composite non-prestressed precast concrete wall panels. Nine flexure tests were conducted on a wall design incorporating 'floating' concrete studs and Glass Fibre Reinforced Polymer (GFRP) connectors. The studs encapsulate and stiffen the connectors, reducing shear deformations. Ultimate loads increased from 58 to 80% that of a composite section as the connectors' reinforcement ratio increased from 2.6 to 9.8%. This design was optimized by reinforcing the studs and integrating them with the structural wythe; new connectors composed of angled steel or Basalt-FRP (BFRP) were used. The load-slip response of the new connector design was studied through 38 double shear push-through tests using various connector diameters and insertion angles. Larger connectors were stronger but more likely to pull out. Seven flexure tests were conducted on the new wall design reinforced with different combinations of steel and BFRP connectors and reinforcement. Composite action varied from 50 to 90% depending on connector and reinforcement material. Following this study, the axial-bending interaction curves were established for the new wall design using both BFRP and steel connectors and reinforcement. Eight panels were axially loaded to predesignated loads then loaded in flexure to failure. A technique is presented to experimentally determine the effective centroid of partially composite sections. Beyond the tension and compression-controlled failure regions of the interaction curve, a third region was observed in between, governed by connector failure. Theoretical models were developed for the bond

  11. Behavior of sandwich panels subjected to bending fatigue, axial compression loading and in-plane bending

    Science.gov (United States)

    Mathieson, Haley Aaron

    This thesis investigates experimentally and analytically the structural performance of sandwich panels composed of glass fibre reinforced polymer (GFRP) skins and a soft polyurethane foam core, with or without thin GFRP ribs connecting skins. The study includes three main components: (a) out-of-plane bending fatigue, (b) axial compression loading, and (c) in-plane bending of sandwich beams. Fatigue studies included 28 specimens and looked into establishing service life (S-N) curves of sandwich panels without ribs, governed by soft core shear failure and also ribbed panels governed by failure at the rib-skin junction. Additionally, the study compared fatigue life curves of sandwich panels loaded under fully reversed bending conditions (R=-1) with panels cyclically loaded in one direction only (R=0) and established the stiffness degradation characteristics throughout their fatigue life. Mathematical models expressing fatigue life and stiffness degradation curves were calibrated and expanded forms for various loading ratios were developed. Approximate fatigue thresholds of 37% and 23% were determined for non-ribbed panels loaded at R=0 and -1, respectively. Digital imaging techniques showed significant shear contribution significantly (90%) to deflections if no ribs used. Axial loading work included 51 specimens and examined the behavior of panels of various lengths (slenderness ratios), skin thicknesses, and also panels of similar length with various rib configurations. Observed failure modes governing were global buckling, skin wrinkling or skin crushing. In-plane bending involved testing 18 sandwich beams of various shear span-to-depth ratios and skin thicknesses, which failed by skin wrinkling at the compression side. The analytical modeling components of axially loaded panels include; a simple design-oriented analytical failure model and a robust non-linear model capable of predicting the full load-displacement response of axially loaded slender sandwich panels

  12. Non-linear elastic deformations

    CERN Document Server

    Ogden, R W

    1997-01-01

    Classic in the field covers application of theory of finite elasticity to solution of boundary-value problems, analysis of mechanical properties of solid materials capable of large elastic deformations. Problems. References.

  13. Anisotropic Ripple Deformation in Phosphorene.

    Science.gov (United States)

    Kou, Liangzhi; Ma, Yandong; Smith, Sean C; Chen, Changfeng

    2015-05-07

    Two-dimensional materials tend to become crumpled according to the Mermin-Wagner theorem, and the resulting ripple deformation may significantly influence electronic properties as observed in graphene and MoS2. Here, we unveil by first-principles calculations a new, highly anisotropic ripple pattern in phosphorene, a monolayer black phosphorus, where compression-induced ripple deformation occurs only along the zigzag direction in the strain range up to 10%, but not the armchair direction. This direction-selective ripple deformation mode in phosphorene stems from its puckered structure with coupled hinge-like bonding configurations and the resulting anisotropic Poisson ratio. We also construct an analytical model using classical elasticity theory for ripple deformation in phosphorene under arbitrary strain. The present results offer new insights into the mechanisms governing the structural and electronic properties of phosphorene crucial to its device applications.

  14. Axisymmetric finite deformation membrane problems

    Energy Technology Data Exchange (ETDEWEB)

    Feng, W.W.

    1980-12-12

    Many biomechanic problems involve the analysis of finite deformation axisymmetric membranes. This paper presents the general formulation for solving a class of axisymmetric membrane problems. The material nonlinearity, as well as the geometric nonlinearity, is considered. Two methods are presented to solve these problems. The first method is solving a set of differential equilibrium equations. The governing equations are reduced to three first-order ordinary-differential equations with explicit derivatives. The second method is the Ritz method where a general potential energy functional valid for all axisymmetric deformed positions is presented. The geometric admissible functions that govern the deformed configuration are written in terms of a series with unknown coefficients. These unknown coefficients are determined by the minimum potential energy principle that of all geometric admissible deformed configurations, the equilibrium configuration minimizes the potential energy. Some examples are presented. A comparison between these two methods is mentioned.

  15. Deterritorializing Drawing - transformation/deformation

    DEFF Research Database (Denmark)

    Brabrand, Helle

    2012-01-01

    and deformation as two very different categories. Moves of transformation produce new places or singularities in a series, making a Figure emerge that switches between force and form and between transformation and deformation. Deformation is acted out by sensation, passing from one ‘order’ to another. Bacon...... deformation, about painting the sensation, which is essentially rhythm, making Figure-rhythm relations appear as vibrations that flow through the body - making resonance. Deleuze, with Bergson, argues that art extracts ’a little time in a pure state’ from the everyday repetitions, and thereby opens...... the capacity of the body to be affected by change. The everyday and the ceremonial body, the ordinary and the aberrant movement – these poles generate a passage rather than a difference from the one to the other: from attitude or position to gesture or kinaesthetic twist. Known from without through perception...

  16. Shape Deformations in Atomic Nuclei

    OpenAIRE

    Hamamoto, Ikuko; Mottelson, Ben R.

    2011-01-01

    The ground states of some nuclei are described by densities and mean fields that are spherical, while others are deformed. The existence of non-spherical shape in nuclei represents a spontaneous symmetry breaking.

  17. Nonlinear Deformable-body Dynamics

    CERN Document Server

    Luo, Albert C J

    2010-01-01

    "Nonlinear Deformable-body Dynamics" mainly consists in a mathematical treatise of approximate theories for thin deformable bodies, including cables, beams, rods, webs, membranes, plates, and shells. The intent of the book is to stimulate more research in the area of nonlinear deformable-body dynamics not only because of the unsolved theoretical puzzles it presents but also because of its wide spectrum of applications. For instance, the theories for soft webs and rod-reinforced soft structures can be applied to biomechanics for DNA and living tissues, and the nonlinear theory of deformable bodies, based on the Kirchhoff assumptions, is a special case discussed. This book can serve as a reference work for researchers and a textbook for senior and postgraduate students in physics, mathematics, engineering and biophysics. Dr. Albert C.J. Luo is a Professor of Mechanical Engineering at Southern Illinois University, Edwardsville, IL, USA. Professor Luo is an internationally recognized scientist in the field of non...

  18. M theory on deformed superspace

    Science.gov (United States)

    Faizal, Mir

    2011-11-01

    In this paper we will analyze a noncommutative deformation of the Aharony-Bergman-Jafferis-Maldacena (ABJM) theory in N=1 superspace formalism. We will then analyze the Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetries for this deformed ABJM theory, and its linear as well as nonlinear gauges. We will show that the sum of the gauge fixing term and the ghost term for this deformed ABJM theory can be expressed as a combination of the total BRST and the total anti-BRST variation, in Landau and nonlinear gauges. We will show that in Landau and Curci-Ferrari gauges deformed ABJM theory is invariant under an additional set of symmetry transformations. We will also discuss the effect that the addition of a bare mass term has on this theory.

  19. CALCULATION OF STRESS AND DEFORMATION IN FUEL ROD CLADDING DURING PELLET-CLADDING INTERACTION

    Directory of Open Access Journals (Sweden)

    Dávid Halabuk

    2015-12-01

    Full Text Available The elementary parts of every fuel assembly, and thus of the reactor core, are fuel rods. The main function of cladding is hermetic separation of nuclear fuel from coolant. The fuel rod works in very specific and difficult conditions, so there are high requirements on its reliability and safety. During irradiation of fuel rods, a state may occur when fuel pellet and cladding interact. This state is followed by changes of stress and deformations in the fuel cladding. The article is focused on stress and deformation analysis of fuel cladding, where two fuels are compared: a fresh one and a spent one, which is in contact with cladding. The calculations are done for 4 different shapes of fuel pellets. It is possible to evaluate which shape of fuel pellet is the most appropriate in consideration of stress and deformation forming in fuel cladding, axial dilatation of fuel, and radial temperature distribution in the fuel rod, based on the obtained results.

  20. Extension of an anisotropic creep model to general high temperature deformation of a single crystal superalloy

    International Nuclear Information System (INIS)

    Pan, L.M.; Ghosh, R.N.; McLean, M.

    1993-01-01

    A physics based model has been developed that accounts for the principal features of anisotropic creep deformation of single crystal superalloys. The present paper extends this model to simulate other types of high temperature deformation under strain controlled test conditions, such as stress relaxation and tension tests at constant strain rate in single crystals subject to axial loading along an arbitrary crystal direction. The approach is applied to the SRR99 single crystal superalloy where a model parameter database is available, determined via analysis of a database of constant stress creep curves. A software package has been generated to simulate the deformation behaviour under complex stress-strain conditions taking into account anisotropic elasticity. (orig.)

  1. A moisture and electric coupling stimulated ionic polymer-metal composite actuator with controllable deformation behavior

    Science.gov (United States)

    Ru, Jie; Zhu, Zicai; Wang, Yanjie; Chen, Hualing; Bian, Changsheng; Luo, Bin; Li, Dichen

    2018-02-01

    Ionic polymer-metal composite (IPMC) actuator can generate large and rapid deformation based on ion migration under a relatively low driving voltage. Under full hydrated conditions, the deformation is always prone to relaxation. At room humidity conditions, the deformation increases substantially at the early stage of actuation, and then decreases gradually. Generally, most researchers considered that the change of water content or relative humidity mainly leads to the deformation instabilities, which severely limits the practical applications of IPMC. In this Letter, a novel actuation mode is proposed to control the deformation behavior of IPMC by employing moisture as an independent or collaborative incentive source together with the electric field. The deformation response is continuously measured under electric field, electric field-moisture coupling stimulus and moisture stimulus. The result shows that moisture can be a favorable driving factor for IPMC actuation. Such an electric field-moisture coupling stimulus can avoid the occurrence of deformation instabilities and guarantee a superior controllable deformation in IPMC actuation. This research provides a new method to obtain stable and large deformation of IPMC, which is of great significance for the guidance of material design and application for IPMC and IPMC-type iEAP materials.

  2. The Effect of Material Property on the Critical Velocity of Randomly Excited Nonlinear Axially Travelling Functionally Graded Plates

    Directory of Open Access Journals (Sweden)

    M. Abedi

    Full Text Available Abstract In this paper, the critical axial speeds of three types of sigmoid, power law and exponential law functionally graded plates for both isotropic and orthotropic cases are obtained via a completely analytic method. The plates are subjected to lateral white noise excitation and show evidence of large deformations. Due to randomness, the conventional deterministic methods fail and a statistical approach must be selected. Here, the probability density function is evaluated analytically for prescribed plates and used to investigate the critical axial velocity of them. Specifically the effect of in-plane forces, mean value of lateral load and the material property on the critical axial speed are studied and discussed for both isotropic and orthotropic functionally graded plates. Since the governing equation is transformed to a non dimensional format, the results can be used for a wide range of plate dimensions. It is shown that the material heterogeneity palys an essential and significant role in increasing or decreasing the critical speed of both isotropic and orthotropic functionally graded plates.

  3. Polygonal deformation bands in sandstone

    Science.gov (United States)

    Antonellini, Marco; Nella Mollema, Pauline

    2017-04-01

    We report for the first time the occurrence of polygonal faults in sandstone, which is compelling given that layer-bound polygonal fault systems have been observed so far only in fine-grained sediments such as clay and chalk. The polygonal faults are dm-wide zones of shear deformation bands that developed under shallow burial conditions in the lower portion of the Jurassic Entrada Fm (Utah, USA). The edges of the polygons are 1 to 5 meters long. The shear deformation bands are organized as conjugate faults along each edge of the polygon and form characteristic horst-like structures. The individual deformation bands have slip magnitudes ranging from a few mm to 1.5 cm; the cumulative average slip magnitude in a zone is up to 10 cm. The deformation bands heaves, in aggregate form, accommodate a small isotropic horizontal extension (strain Crosscutting relationships are rare. The interactions of the deformation bands are similar to those of mode I opening fractures. Density inversion, that takes place where under-compacted and over-pressurized layers (Carmel Fm) lay below normally compacted sediments (Entrada Sandstone), may be an important process for polygonal deformation bands formation. The gravitational sliding and soft sediment structures typically observed within the Carmel Fm support this hypothesis. Soft sediment deformation may induce polygonal faulting in the section of the Entrada Sandstone just above the Carmel Fm. The permeability of the polygonal deformation bands is approximately 10-14 to 10-13 m2, which is less than the permeability of the host, Entrada Sandstone (range 10-12 to 10-11 m2). The documented fault networks have important implications for evaluating the geometry of km-scale polygonal fault systems in the subsurface, top seal integrity, as well as constraining paleo-tectonic stress regimes.

  4. Unitary deformations of counterdiabatic driving

    Science.gov (United States)

    Takahashi, Kazutaka

    2015-04-01

    We study a deformation of the counterdiabatic-driving Hamiltonian as a systematic strategy for an adiabatic control of quantum states. Using a unitary transformation, we design a convenient form of the driver Hamiltonian. We apply the method to a particle in a confining potential and discrete systems to find explicit forms of the Hamiltonian and discuss the general properties. The method is derived by using the quantum brachistochrone equation, which shows the existence of a nontrivial dynamical invariant in the deformed system.

  5. High Precision Axial Coordinate Readout for an Axial 3-D PET Detector Module using a Wave Length Shifter Strip Matrix

    CERN Document Server

    Braem, André; Joram, C; Séguinot, Jacques; Weilhammer, P; De Leo, R; Nappi, E; Lustermann, W; Schinzel, D; Johnson, I; Renker, D; Albrecht, S

    2007-01-01

    We describe a novel method to extract the axial coordinate from a matrix of long axially oriented crystals, which is based on wavelength shifting plastic strips. The method allows building compact 3-D axial gamma detector modules for PET scanners with excellent 3-dimensional spatial, timing and energy resolution while keeping the number of readout channels reasonably low. A voxel resolution of about 10 mm3 is expected. We assess the performance of the method in two independent ways, using classical PMTs and G-APDs to read out the LYSO (LSO) scintillation crystals and the wavelength shifting strips. We observe yields in excess of 35 photoelectrons from the strips for a 511 keV gamma and reconstruct the axial coordinate with a precision of about 2.5 mm (FWHM).

  6. A deformable head and neck phantom with in-vivo dosimetry for adaptive radiotherapy quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Graves, Yan Jiang [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843 and Department of Physics, University of California San Diego, La Jolla, California 92093 (United States); Smith, Arthur-Allen; Mcilvena, David; Manilay, Zherrina; Lai, Yuet Kong [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093 (United States); Rice, Roger; Mell, Loren; Cerviño, Laura, E-mail: lcervino@ucsd.edu, E-mail: steve.jiang@utsouthwestern.edu [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843 (United States); Jia, Xun; Jiang, Steve B., E-mail: lcervino@ucsd.edu, E-mail: steve.jiang@utsouthwestern.edu [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843 and Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75235 (United States)

    2015-04-15

    Purpose: Patients’ interfractional anatomic changes can compromise the initial treatment plan quality. To overcome this issue, adaptive radiotherapy (ART) has been introduced. Deformable image registration (DIR) is an important tool for ART and several deformable phantoms have been built to evaluate the algorithms’ accuracy. However, there is a lack of deformable phantoms that can also provide dosimetric information to verify the accuracy of the whole ART process. The goal of this work is to design and construct a deformable head and neck (HN) ART quality assurance (QA) phantom with in vivo dosimetry. Methods: An axial slice of a HN patient is taken as a model for the phantom construction. Six anatomic materials are considered, with HU numbers similar to a real patient. A filled balloon inside the phantom tissue is inserted to simulate tumor. Deflation of the balloon simulates tumor shrinkage. Nonradiopaque surface markers, which do not influence DIR algorithms, provide the deformation ground truth. Fixed and movable holders are built in the phantom to hold a diode for dosimetric measurements. Results: The measured deformations at the surface marker positions can be compared with deformations calculated by a DIR algorithm to evaluate its accuracy. In this study, the authors selected a Demons algorithm as a DIR algorithm example for demonstration purposes. The average error magnitude is 2.1 mm. The point dose measurements from the in vivo diode dosimeters show a good agreement with the calculated doses from the treatment planning system with a maximum difference of 3.1% of prescription dose, when the treatment plans are delivered to the phantom with original or deformed geometry. Conclusions: In this study, the authors have presented the functionality of this deformable HN phantom for testing the accuracy of DIR algorithms and verifying the ART dosimetric accuracy. The authors’ experiments demonstrate the feasibility of this phantom serving as an end

  7. Marginally Stable Nuclear Burning

    Science.gov (United States)

    Strohmayer, Tod E.; Altamirano, D.

    2012-01-01

    Thermonuclear X-ray bursts result from unstable nuclear burning of the material accreted on neutron stars in some low mass X-ray binaries (LMXBs). Theory predicts that close to the boundary of stability oscillatory burning can occur. This marginally stable regime has so far been identified in only a small number of sources. We present Rossi X-ray Timing Explorer (RXTE) observations of the bursting, high- inclination LMXB 4U 1323-619 that reveal for the first time in this source the signature of marginally stable burning. The source was observed during two successive RXTE orbits for approximately 5 ksec beginning at 10:14:01 UTC on March 28, 2011. Significant mHz quasi- periodic oscillations (QPO) at a frequency of 8.1 mHz are detected for approximately 1600 s from the beginning of the observation until the occurrence of a thermonuclear X-ray burst at 10:42:22 UTC. The mHz oscillations are not detected following the X-ray burst. The average fractional rms amplitude of the mHz QPOs is 6.4% (3 - 20 keV), and the amplitude increases to about 8% below 10 keV.This phenomenology is strikingly similar to that seen in the LMXB 4U 1636-53. Indeed, the frequency of the mHz QPOs in 4U 1323-619 prior to the X-ray burst is very similar to the transition frequency between mHz QPO and bursts found in 4U 1636-53 by Altamirano et al. (2008). These results strongly suggest that the observed QPOs in 4U 1323-619 are, like those in 4U 1636-53, due to marginally stable nuclear burning. We also explore the dependence of the energy spectrum on the oscillation phase, and we place the present observations within the context of the spectral evolution of the accretion-powered flux from the source.

  8. Multi-axial active isolation for seismic protection of buildings

    Science.gov (United States)

    Chang, Chia-Ming

    Structural control technology has been widely accepted as an effective means for the protection of structures against seismic hazards. Passive base isolation is one of the common structural control techniques used to enhance the performance of structures subjected to severe earthquake excitations. Isolation bearings employed at the base of a structure naturally increase its flexibility, but concurrently result in large base displacements. The combination of base isolation with active control, i.e., active base isolation, creates the possibility of achieving a balanced level of control performance, reducing both floor accelerations as well as base displacements. Many theoretical papers have been written by researchers regarding active base isolation, and a few experiments have been performed to verify these theories; however, challenges in appropriately scaling the structural system and modeling the complex nature of control-structure interaction have limited the applicability of these results. Moreover, most experiments only focus on the implementation of active base isolation under unidirectional excitations. Earthquakes are intrinsically multi-dimensional, resulting in out-of-plane responses, including torsional responses. Therefore, an active isolation system for buildings using multi-axial active control devices against multi-directional excitations must be considered. The focus of this dissertation is the development and experimental verification of active isolation strategies for multi-story buildings subjected to bi-directional earthquake loadings. First, a model building is designed to match the characteristics of a representative full-scale structure. The selected isolation bearings feature low friction and high vertical stiffness, providing stable behavior. In the context of the multi-dimensional response control, three, custom-manufactured actuators are employed to mitigate both in-plane and out-of-plane responses. To obtain a high-fidelity model of the

  9. Plastic Fibula Bone Deformity with Ipsilateral Fracture of Tibiain Adults: A Case Report

    OpenAIRE

    Abbas Abdoli Tafti; Sanazsadat Sajadi; Maryam Shahmoradi

    2015-01-01

    Plastic bowing is a constant deformation of long bones occurring after a long standing force to bone. This type of fracture is seen in children and is uncommon in the adults. In this paper we report a case of fibular plastic deformity with ipsilateral tibia fracture in a 20 years old man that occurred after a direct hit. At the initial examination vital signs were stable and radiography of tibia and fibula fracture with plastic deformation were clear. In order to treat him we performed fib...

  10. Estimation of Continuous Velocity Model Variations in Rock Deformation Tests.

    Science.gov (United States)

    Flynn, J. W.; Tomas, R.; Benson, P. M.

    2017-12-01

    Seismic interferometry, using either seismic waves coda or ambient noise, is a passive technique to image the sub-surface seismic velocity structure, which directly relates to the physical properties of the material through which they travel. The methodology estimates the Green's function for the volume between two seismic stations by cross-correlating long time series of ambient noise recorded at both stations, with the Green's function being effectively the seismogram recorded at one station due to an impulsive or instantaneous energy source at the second station. In laboratory rock deformation experiments, changes in the velocity structure of the rock sample are generally measured through active surveys using an array of AE piezoelectric P-wave transducers, producing a time series of ultrasonic velocities in both axial and radial directions. The velocity information from the active surveys is used to provide a time dependent velocity model for the inversion of AE event source locations. These velocity measurements are carried out at regular intervals throughout the laboratory test, causing the interruption of passive AE monitoring for the length of the surveys. There is therefore a trade-off between the frequency at which the active velocity surveys are carried out to optimise the velocity model and the availability of a complete AE record during the rock deformation test.This study proposes to use noise interferometry to provide a continuous measurement of velocity variations in a rock sample during a laboratory rock deformation experiment without the need to carry out active velocity surveys while simultaneously passively monitoring AE activity. The continuous noise source in this test, is an AE transducer fed with a white gaussian noise signal from a function generator. Data from all AE transducers is continuously acquired and recorded during the deformation experiment. The cross correlation of the continuous AE record is used to produce a continuous velocity

  11. Intrinsic excitations in deformed nuclei: characteristic predictions of the IBA

    International Nuclear Information System (INIS)

    Casten, R.F.

    1982-01-01

    Deformed nuclei represent perhaps the largest and best studied class of nuclear level schemes. The Interacting Boson Approximation (IBA) model is devised so as to provide a general framework for the description of low lying collective states in nuclei spanning vibrational, rotational (i.e., deformed) and axially asymmetric types as well as the transitional species intermediate between these limiting cases. The juxtaposition of these two statements makes it all the more surprising that until recently there had been no thorough test of the model in such nuclei. Partly, the explanation for this lies in the type of data required for an adequate test. Since the IBA predicts a broad range of collective states it requires a correspondingly thorough empirical test. Moreover, in deformed nuclei, though the characteristic predictions that distinguish the IBA from the traditional, familiar collective model of harmonic β and γ vibrations are important, their clearest manifestation occurs in very weak, hard-to-detect low energy transitions between excited vibrational bands (in particular between β and γ bands), that had not heretofore been systematically observed. The present brief summary will begin with a review of the properties of the (n,γ) reaction that render it a useful empirical tool for such studies, and follow this with a description of the results of the 168 Er study and the application of the IBA model to the resultant level scheme. The discussion will then be generalized to other deformed nuclei and to the inherent systematic predictions that must characterize the IBA for such nuclei. Many of these ideas will be related to the role of finite boson number in the IBA

  12. Axial Lengths in Children with Recessive Cornea Plana.

    Science.gov (United States)

    Al Hazimi, Amro; Khan, Arif O

    2015-06-01

    While flat keratometry contributes to the hyperopia and associated refractive accommodative esotropia that is part of recessive cornea plana, whether or not axial lengths are abnormally short in the disease is unclear. In this study we assess this possibility. Prospective (2010-2012) axial length measurement (IOLmaster; Carl Zeiss, Oberkochen, Germany) of affected right eyes and comparison to right eyes with refractive accommodative esotropia only. Keratometry and refraction were also performed. For eight affected right eyes (age 10-12 years; seven families) axial length ranged from 21.46-24.80 mm (mean 23.34). Best corrected visual acuity ranged from 20/25 to 20/50, keratometry from 25.33-39.80 diopters (D) [mean 31.80], and refraction from +2.00 to +14.00 D (mean +7.22). For 50 control right eyes (age 4-12 years), axial length ranged from 19.87-23.66 mm (mean 21.6). Best-corrected visual acuity was 20/25 or better, keratometry ranged from 39.81-46.25 D (mean 42.42), and refraction from +2.25 to +8.00 D (mean 4.71). Axial lengths were longer in the affected group (2-tailed unpaired t-test p value 0.000005) despite greater hyperopia (2-tailed unpaired t-test p value 0.001). Despite greater hyperopia, axial lengths were longer in eyes with recessive cornea plana, evidence that axial lengths are not shortened by the disease. Keratometry in children with cornea plana was below the range of controls and was the major factor underlying the phenotype's hyperopia.

  13. Deformed configurations, band structures and spectroscopic ...

    Indian Academy of Sciences (India)

    2014-03-20

    Mar 20, 2014 ... The deformed configurations and rotational band structures in =50 Ge and Se nuclei are studied by deformed Hartree–Fock with quadrupole constraint and angular momentum projection. Apart from the `almost' spherical HF solution, a well-deformed configuration occurs at low excitation. A deformed ...

  14. Associative and Lie deformations of Poisson algebras

    OpenAIRE

    Remm, Elisabeth

    2011-01-01

    Considering a Poisson algebra as a non associative algebra satisfying the Markl-Remm identity, we study deformations of Poisson algebras as deformations of this non associative algebra. This gives a natural interpretation of deformations which preserves the underlying associative structure and we study deformations which preserve the underlying Lie algebra.

  15. High temperature deformation behavior of gradually pressurized zircaloy-4 tubes

    International Nuclear Information System (INIS)

    Suzuki, Motoye

    1982-03-01

    In order to obtain preliminary perspectives on fuel cladding deformation behavior under changing temperature and pressure conditions in a hypothetical loss-of-coolant accident of PWR, a Zircaloy-4 tube burst test was conducted in both air and 99.97% Ar atomospheres. The tubes were directly heated by AC-current and maintained at various temperatures, and pressurized gradually until rupture occurred. Rupture circumferential strains were generally larger in Ar gas than in air and attained a maximum around 1100 K in both atmospheres. Some tube tested in air produced axially-extended long balloons, which proved not to be explained by such properties or ideas as effect of cooling on strain rate, superplasticity, geometrical plastic instability and stresses generated by surface oxide layer. A cause of the long balloon may be obtained in the anisotropy of the material structure. But even a qualitative analysis based on this property can not be made due to insufficient data of the anisotropy. (author)

  16. Bilateral cleft lip nasal deformity

    Directory of Open Access Journals (Sweden)

    Singh Arun

    2009-01-01

    Full Text Available Bilateral cleft lip nose deformity is a multi-factorial and complex deformity which tends to aggravate with growth of the child, if not attended surgically. The goals of primary bilateral cleft lip nose surgery are, closure of the nasal floor and sill, lengthening of the columella, repositioning of the alar base, achieving nasal tip projection, repositioning of the lower lateral cartilages, and reorienting the nares from horizontal to oblique position. The multiplicity of procedures in the literature for correction of this deformity alludes to the fact that no single procedure is entirely effective. The timing for surgical intervention and its extent varies considerably. Early surgery on cartilage may adversely affect growth and development; at the same time, allowing the cartilage to grow in an abnormal position and contributing to aggravation of deformity. Some surgeons advocate correction of deformity at an early age. However, others like the cartilages to grow and mature before going in for surgery. With peer pressure also becoming an important consideration during the teens, the current trend is towards early intervention. There is no unanimity in the extent of nasal dissection to be done at the time of primary lip repair. While many perform limited nasal dissection for the fear of growth retardation, others opt for full cartilage correction at the time of primary surgery itself. The value of naso-alveolar moulding (NAM too is not universally accepted and has now more opponents than proponents. Also most centres in the developing world have neither the personnel nor the facilities for the same. The secondary cleft nasal deformity is variable and is affected by the extent of the original abnormality, any prior surgeries performed and alteration due to nasal growth. This article reviews the currently popular methods for correction of nasal deformity associated with bilateral cleft lip, it′s management both at the time of cleft lip repair

  17. Axial compression behaviour of reinforced wallettes fabricated using wood-wool cement panel

    Science.gov (United States)

    Noh, M. S. Md; Kamarudin, A. F.; Mokhatar, S. N.; Jaudin, A. R.; Ahmad, Z.; Ibrahim, A.; Muhamad, A. A.

    2018-04-01

    Wood-wool cement composite panel (WWCP) is one of wood based composite material that produced in a stable panel form and suitable to be used as building wall system to replace non-ecofriendly material such as brick and other masonry element. Heavy construction material such as brick requires more manpower and consume a lot of time to build the wall panel. WWCP is a lightweight material with a density range from 300 kg/m3 to 500 kg/m3 and also capable to support an imposed load from the building. This study reported on the axial compression behaviour of prefabricated reinforced wallettes constructed with wood-wool cement panel. A total of six specimens were fabricated using two layers of cross laminated WWCP bonded with normal mortar paste (Portland cement) at a mix ratio of 1:3 (cement : sand). As part of lifting mechanism, the wallettes were equipped with three steel reinforcement (T12) that embedded inside the core of wallettes. Three replicates of wallettes specimens with dimension 600 mm width and 600 mm length were fabricated without surface plaster and with 16 mm thickness of surface plaster. The wallettes were tested under axial compression load after 28 days of fabrication until failure. The result indicated that, the application of surface plaster significantly increases the loading capacity about 35 % and different orientation of the panels improve the bonding strength of the wall.

  18. Numerical Study on the Acoustic Characteristics of an Axial Fan under Rotating Stall Condition

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2017-11-01

    Full Text Available Axial fan is an important piece of equipment in the thermal power plant that provides enough air for combustion of coal. This paper focuses on the aerodynamic noise characteristics of an axial fan in the development from stall inception to stall cells. The aerodynamic noise characteristic of monitoring region in time and frequency domains was simulated employing the large-eddy simulation (LES, with the addition of throttle setting and the Ffowcs Williams-Hawkings (FW-H noise model. The numerical results show that, under the design condition, the acoustic pressure presents regular periodicity along with the time. The noise energy is concentrated with high energy of the fundamental frequency and high order harmonics. During the stall inception stage, the acoustic pressure amplitude starts fluctuating and discrete frequencies are increased significantly in the low frequency; among them, there are three obvious discrete frequencies: 27.66 Hz, 46.10 Hz and 64.55 Hz. On the rotating stall condition, the fluctuation of the acoustic pressure level and amplitude are more serious than that mentioned above. During the whole evolution process, the acoustic pressure peak is difficult to keep stable all the time, and a sudden increase of the peak value at the 34.5th revolution corresponds to the relative velocity’s first sudden increase at the time when the valve coefficient is 0.780.

  19. Nonlinear control for core power of pressurized water nuclear reactors using constant axial offset strategy

    Directory of Open Access Journals (Sweden)

    Gholam Reza Ansarifar

    2015-12-01

    Full Text Available One of the most important operations in nuclear power plants is load following, in which an imbalance of axial power distribution induces xenon oscillations. These oscillations must be maintained within acceptable limits otherwise the nuclear power plant could become unstable. Therefore, bounded xenon oscillation is considered to be a constraint for the load following operation. In this paper, the design of a sliding mode control (SMC, which is a robust nonlinear controller, is presented. SMC is a means to control pressurized water nuclear reactor (PWR power for the load following operation problem in a way that ensures xenon oscillations are kept bounded within acceptable limits. The proposed controller uses constant axial offset (AO strategy to ensure xenon oscillations remain bounded. The constant AO is a robust state constraint for the load following problem. The reactor core is simulated based on the two-point nuclear reactor model with a three delayed neutron groups. The stability analysis is given by means of the Lyapunov approach, thus the control system is guaranteed to be stable within a large range. The employed method is easy to implement in practical applications and moreover, the SMC exhibits the desired dynamic properties during the entire output-tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness, and stability. Results show that the proposed controller for the load following operation is so effective that the xenon oscillations are kept bounded in the given region.

  20. Investigation of Turbulent Tip Leakage Vortex in an Axial Water Jet Pump with Large Eddy Simulation

    Science.gov (United States)

    Hah, Chunill; Katz, Joseph

    2012-01-01

    Detailed steady and unsteady numerical studies were performed to investigate tip clearance flow in an axial water jet pump. The primary objective is to understand physics of unsteady tip clearance flow, unsteady tip leakage vortex, and cavitation inception in an axial water jet pump. Steady pressure field and resulting steady tip leakage vortex from a steady flow analysis do not seem to explain measured cavitation inception correctly. The measured flow field near the tip is unsteady and measured cavitation inception is highly transient. Flow visualization with cavitation bubbles shows that the leakage vortex is oscillating significantly and many intermittent vortex ropes are present between the suction side of the blade and the tip leakage core vortex. Although the flow field is highly transient, the overall flow structure is stable and a characteristic frequency seems to exist. To capture relevant flow physics as much as possible, a Reynolds-averaged Navier-Stokes (RANS) calculation and a Large Eddy Simulation (LES) were applied for the current investigation. The present study reveals that several vortices from the tip leakage vortex system cross the tip gap of the adjacent blade periodically. Sudden changes in local pressure field inside tip gap due to these vortices create vortex ropes. The instantaneous pressure filed inside the tip gap is drastically different from that of the steady flow simulation. Unsteady flow simulation which can calculate unsteady vortex motion is necessary to calculate cavitation inception accurately even at design flow condition in such a water jet pump.

  1. Continuous millennial decrease of the Earth's magnetic axial dipole

    Science.gov (United States)

    Poletti, Wilbor; Biggin, Andrew J.; Trindade, Ricardo I. F.; Hartmann, Gelvam A.; Terra-Nova, Filipe

    2018-01-01

    Since the establishment of direct estimations of the Earth's magnetic field intensity in the first half of the nineteenth century, a continuous decay of the axial dipole component has been observed and variously speculated to be linked to an imminent reversal of the geomagnetic field. Furthermore, indirect estimations from anthropologically made materials and volcanic derivatives suggest that this decrease began significantly earlier than direct measurements have been available. Here, we carefully reassess the available archaeointensity dataset for the last two millennia, and show a good correspondence between direct (observatory/satellite) and indirect (archaeomagnetic) estimates of the axial dipole moment creating, in effect, a proxy to expand our analysis back in time. Our results suggest a continuous linear decay as the most parsimonious long-term description of the axial dipole variation for the last millennium. We thus suggest that a break in the symmetry of axial dipole moment advective sources occurred approximately 1100 years earlier than previously described. In addition, based on the observed dipole secular variation timescale, we speculate that the weakening of the axial dipole may end soon.

  2. Amphiregulin Antibody and Reduction of Axial Elongation in Experimental Myopia

    Directory of Open Access Journals (Sweden)

    Wen Jun Jiang

    2017-03-01

    Full Text Available To examine the mechanism of ocular axial elongation in myopia, guinea pigs (age: 2–3 weeks which either underwent unilateral or bilateral lens-induced myopization (group 1 or which were primarily myopic at baseline (group 2 received unilateral intraocular injections of amphiregulin antibody (doses: 5, 10, or 15 μg three times in intervals of 9 days. A third group of emmetropic guinea pigs got intraocular unilateral injections of amphiregulin (doses: 0.25, 0.50 or 1.00 ng, respectively. In each group, the contralateral eyes received intraocular injections of Ringer's solution. In intra-animal inter-eye comparison and intra-eye follow-up comparison in groups 1 and 2, the study eyes as compared to the contralateral eyes showed a dose-dependent reduction in axial elongation. In group 3, study eyes and control eyes did not differ significantly in axial elongation. Immunohistochemistry revealed amphiregulin labelling at the retinal pigment epithelium in eyes with lens-induced myopization and Ringer's solution injection, but not in eyes with amphiregulin antibody injection. Intraocular injections of amphiregulin-antibody led to a reduction of lens-induced axial myopic elongation and of the physiological eye enlargement in young guinea pigs. In contrast, intraocularly injected amphiregulin in a dose of ≤1 ng did not show a significant effect. Amphiregulin may be one of several essential molecular factors for axial elongation.

  3. Analysis of axial compressive loaded beam under random support excitations

    Science.gov (United States)

    Xiao, Wensheng; Wang, Fengde; Liu, Jian

    2017-12-01

    An analytical procedure to investigate the response spectrum of a uniform Bernoulli-Euler beam with axial compressive load subjected to random support excitations is implemented based on the Mindlin-Goodman method and the mode superposition method in the frequency domain. The random response spectrum of the simply supported beam subjected to white noise excitation and to Pierson-Moskowitz spectrum excitation is investigated, and the characteristics of the response spectrum are further explored. Moreover, the effect of axial compressive load is studied and a method to determine the axial load is proposed. The research results show that the response spectrum mainly consists of the beam's additional displacement response spectrum when the excitation is white noise; however, the quasi-static displacement response spectrum is the main component when the excitation is the Pierson-Moskowitz spectrum. Under white noise excitation, the amplitude of the power spectral density function decreased as the axial compressive load increased, while the frequency band of the vibration response spectrum increased with the increase of axial compressive load.

  4. Modeling Effects of Axial Extension on Arterial Growth and Remodeling

    Science.gov (United States)

    Valentín, A.; Humphrey, J.D.

    2013-01-01

    Diverse mechanical perturbations elicit arterial growth and remodeling responses that appear to optimize structure and function so as to achieve mechanical homeostasis. For example, it is well known that functional adaptations to sustained changes in transmural pressure and blood flow primarily affect wall thickness and caliber to restore circumferential and wall shear stresses toward normal. More recently, however, it has been shown that changes in axial extension similarly prompt dramatic cell and matrix reorganization and turnover, resulting in marked changes in unloaded geometry and mechanical behavior that presumably restore axial stress toward normal. Because of the inability to infer axial stress from in vivo measurements, simulations are needed to examine this hypothesis and to guide the design of future experiments. In this paper, we show that a constrained mixture model predicts salient features of observed responses to step increases in axial extension, including marked increases in fibrous constituent production, leading to a compensatory lengthening that restores original mechanical behavior. Because axial extension can be modified via diverse surgical procedures, including bypass operations and exploited in tissue regeneration research, there is a need for increased attention to this important aspect of arterial biomechanics and mechanobiology. PMID:19649667

  5. Plastic deformation of indium nanostructures

    International Nuclear Information System (INIS)

    Lee, Gyuhyon; Kim, Ju-Young; Burek, Michael J.; Greer, Julia R.; Tsui, Ting Y.

    2011-01-01

    Highlights: → Indium nanopillars display two different deformation mechanisms. → ∼80% exhibited low flow stresses near that of bulk indium. → Low strength nanopillars have strain rate sensitivity similar to bulk indium. → ∼20% of compressed indium nanopillars deformed at nearly theoretical strengths. → Low-strength samples do not exhibit strength size effects. - Abstract: Mechanical properties and morphology of cylindrical indium nanopillars, fabricated by electron beam lithography and electroplating, are characterized in uniaxial compression. Time-dependent deformation and influence of size on nanoscale indium mechanical properties were investigated. The results show two fundamentally different deformation mechanisms which govern plasticity in these indium nanostructures. We observed that the majority of indium nanopillars deform at engineering stresses near the bulk values (Type I), with a small fraction sustaining flow stresses approaching the theoretical limit for indium (Type II). The results also show the strain rate sensitivity and flow stresses in Type I indium nanopillars are similar to bulk indium with no apparent size effects.

  6. Static response of deformable microchannels

    Science.gov (United States)

    Christov, Ivan C.; Sidhore, Tanmay C.

    2017-11-01

    Microfluidic channels manufactured from PDMS are a key component of lab-on-a-chip devices. Experimentally, rectangular microchannels are found to deform into a non-rectangular cross-section due to fluid-structure interactions. Deformation affects the flow profile, which results in a nonlinear relationship between the volumetric flow rate and the pressure drop. We develop a framework, within the lubrication approximation (l >> w >> h), to self-consistently derive flow rate-pressure drop relations. Emphasis is placed on handling different types of elastic response: from pure plate-bending, to half-space deformation, to membrane stretching. The ``simplest'' model (Stokes flow in a 3D rectangular channel capped with a linearly elastic Kirchhoff-Love plate) agrees well with recent experiments. We also simulate the static response of such microfluidic channels under laminar flow conditions using ANSYSWorkbench. Simulations are calibrated using experimental flow rate-pressure drop data from the literature. The simulations provide highly resolved deformation profiles, which are difficult to measure experimentally. By comparing simulations, experiments and our theoretical models, we show good agreement in many flow/deformation regimes, without any fitting parameters.

  7. Microstructural and mechanical properties of AA1100 aluminum processed by multi-axial incremental forging and shearing

    International Nuclear Information System (INIS)

    Montazeri-Pour, M.; Parsa, M.H.; Jafarian, H.R.; Taieban, S.

    2015-01-01

    Multi-axial incremental forging and shearing (MAIFS), as a new severe plastic deformation technique, was successfully applied up to eight passes on the workpieces of commercially pure Al (AA1100). The microstructure evolutions and mechanisms of the grain refinement in the billets deformed through various passes of process were studied using the electron backscatter diffraction (EBSD) analysis. Microhardness measurements and tensile tests were carried out to evaluate the mechanical properties and deformation behavior of the material after successive passes of the MAIFS process. Measured microhardness evolution indicated that while the distribution of hardness was non-uniform after odd-numbered passes up to four passes, but thereafter outstanding deformation homogeneity was achieved when the consecutive MAIFS passes were applied. Tensile tests indicated that yield stress and ultimate tensile strength increased rapidly during the primary pass of process but thereafter there was only a minor increase up to four passes. After that, a little drop could be observed in strength and then it reached to a saturated magnitude. Measured microhardness distribution values exhibited the same trend, viz. it increased through successive passes to a limiting value beyond which it showed a minor decline by disappearance of points having maximum hardness. Some coarsening was taken place and the dislocation walls between the boundaries were reduced significantly in going from four to six passes. It was suggested that the absorption of the dislocations into grain boundaries as an effective recovery process under large deformations and short-range migration of grain boundaries might be significant mechanisms responsible for the softening observed after four passes of process

  8. Optimization Design and Experimental Study of Low-Pressure Axial Fan with Forward-Skewed Blades

    Directory of Open Access Journals (Sweden)

    Li Yang

    2007-01-01

    Full Text Available This paper presents an experimental study of the optimization of blade skew in low pressure axial fan. Using back propagation (BP neural network and genetic algorithm (GA, the optimization was performed for a radial blade. An optimized blade is obtained through blade forward skew. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the optimized blade demonstrated improvements in efficiency, total pressure ratio, stable operating range, and aerodynamic noise. Detailed flow measurement was performed in outlet flow field for investigating the responsible flow mechanisms. The optimized blade can cause a spanwise redistribution of flow toward the blade midspan and reduce tip loading. This results in reduced significantly total pressure loss near hub and shroud endwall region, despite the slight increase of total pressure loss at midspan. In addition, the measured spectrums show that the broadband noise of the impeller is dominant.

  9. Making Deformable Template Models Operational

    DEFF Research Database (Denmark)

    Fisker, Rune

    2000-01-01

    for estimation of the model parameters, which applies a combination of a maximum likelihood and minimum distance criterion. Another contribution is a very fast search based initialization algorithm using a filter interpretation of the likelihood model. These two methods can be applied to most deformable template......Deformable template models are a very popular and powerful tool within the field of image processing and computer vision. This thesis treats this type of models extensively with special focus on handling their common difficulties, i.e. model parameter selection, initialization and optimization....... A proper handling of the common difficulties is essential for making the models operational by a non-expert user, which is a requirement for intensifying and commercializing the use of deformable template models. The thesis is organized as a collection of the most important articles, which has been...

  10. Foam rheology at large deformation

    Science.gov (United States)

    Géminard, J.-C.; Pastenes, J. C.; Melo, F.

    2018-04-01

    Large deformations are prone to cause irreversible changes in materials structure, generally leading to either material hardening or softening. Aqueous foam is a metastable disordered structure of densely packed gas bubbles. We report on the mechanical response of a foam layer subjected to quasistatic periodic shear at large amplitude. We observe that, upon increasing shear, the shear stress follows a universal curve that is nearly exponential and tends to an asymptotic stress value interpreted as the critical yield stress at which the foam structure is completely remodeled. Relevant trends of the foam mechanical response to cycling are mathematically reproduced through a simple law accounting for the amount of plastic deformation upon increasing stress. This view provides a natural interpretation to stress hardening in foams, demonstrating that plastic effects are present in this material even for minute deformation.

  11. Ball Screw Actuator Including an Axial Soft Stop

    Science.gov (United States)

    Wingett, Paul T. (Inventor); Forrest, Steven Talbert (Inventor); Abel, Steve (Inventor); Woessner, George (Inventor); Hanlon, Casey (Inventor)

    2016-01-01

    An actuator includes an actuator housing, a ball screw, and an axial soft stop assembly. The ball screw extends through the actuator housing and has a first end and a second end. The ball screw is coupled to receive a drive force and is configured, upon receipt of the drive force, to selectively move in a retract direction and an extend direction. The axial soft stop assembly is disposed within the actuator housing. The axial soft stop assembly is configured to be selectively engaged by the ball screw and, upon being engaged thereby, to translate, with compliance, a predetermined distance in the extend direction, and to prevent further movement of the ball screw upon translating the predetermined distance.

  12. Improvement of axial power distribution synthesis methodology in CPC

    International Nuclear Information System (INIS)

    Kim, H. H.; Gee, S. G.;; Kim, Y. B.; In, W. K.

    2003-01-01

    The capability of axial power distribution synthesis in CPC plays an important role in determining the DNBR and LPD trip caused by CPC. The axial power distribution is synthesized using the cubic spline function based on the three excore detector signals. The axial power distributions are categorized into 8 function sets and each sets are stored as pre-calculated values in CPC to save the calculation time. In this study, the additional function sets, the real break-point function sets and the polynomial function are suggested to evaluate the possibility of improving the synthesis capability in CPC. In addition, RMS errors are compared and evaluated for each synthesis method. As a result, it was confirmed that the function sets stored in CPC were not optimal. The analysis result showed that RMS error could be reduced by selecting the proper function sets suggested in this study

  13. Axially modulated arch resonator for logic and memory applications

    KAUST Repository

    Hafiz, Md Abdullah Al

    2018-01-17

    We demonstrate reconfigurable logic and random access memory devices based on an axially modulated clamped-guided arch resonator. The device is electrostatically actuated and the motional signal is capacitively sensed, while the resonance frequency is modulated through an axial electrostatic force from the guided side of the microbeam. A multi-physics finite element model is used to verify the effectiveness of the axial modulation. We present two case studies: first, a reconfigurable two-input logic gate based on the linear resonance frequency modulation, and second, a memory element based on the hysteretic frequency response of the resonator working in the nonlinear regime. The energy consumptions of the device for both logic and memory operations are in the range of picojoules, promising for energy efficient alternative computing paradigm.

  14. Program for beam optical computation of axial symmetrical electrostatic systems

    International Nuclear Information System (INIS)

    Ke Jianlin; Wu Chunlei; Zhou Changgeng

    2012-01-01

    The beam optical computation of axial symmetrical electrostatic systems is very important in the design and test of low-energy accelerators such as Cock-Croft and Van de Graaf accelerators. In this paper, a program for the beam optical computation of these structures has been developed using transfer matrix method. The electrostatic field region is divided into several small intervals in the program, and then the beam envelope is calculated interval-to-interval from the axial potential distribution, which is calculated by other electromagnetic field simulation software such as Maxwell SV. Space charge effect is included so that the program can be used in the computation of intense beam, while nonlinear effect is beyond its ability. The program can be used in the calculation of beam optics in most complicated axial symmetrical electrostatic fields, and the computing time required is very short. (authors)

  15. Progressive atlanto-axial subluxation in Behcet's disease

    International Nuclear Information System (INIS)

    Kim, Sang-hyuk; Eoh, Whan

    2010-01-01

    Behcet's disease is a chronic inflammatory condition involving several organs, such as the skin, mucous membranes, eyes, joints, intestines, lungs and central nervous system. It rarely affects the spinal column. We describe a case of progressive atlanto-axial subluxation in a 44-year-old woman with Behcet's disease. The patient started complaining of posterior neck pain 10 years after the diagnosis of her Behcet's disease. Initial radiographs showed no abnormal finding, but follow-up radiographs 6 month later demonstrated atlanto-axial subluxation. To the best of our knowledge, this is the second reported case in the worldwide literature of an atlanto-axial instability in a patient with Behcet's disease. (orig.)

  16. Bifurcation and chaos of an axially accelerating viscoelastic beam

    International Nuclear Information System (INIS)

    Yang Xiaodong; Chen Liqun

    2005-01-01

    This paper investigates bifurcation and chaos of an axially accelerating viscoelastic beam. The Kelvin-Voigt model is adopted to constitute the material of the beam. Lagrangian strain is used to account for the beam's geometric nonlinearity. The nonlinear partial-differential equation governing transverse motion of the beam is derived from the Newton second law. The Galerkin method is applied to truncate the governing equation into a set of ordinary differential equations. By use of the Poincare map, the dynamical behavior is identified based on the numerical solutions of the ordinary differential equations. The bifurcation diagrams are presented in the case that the mean axial speed, the amplitude of speed fluctuation and the dynamic viscoelasticity is respectively varied while other parameters are fixed. The Lyapunov exponent is calculated to identify chaos. From numerical simulations, it is indicated that the periodic, quasi-periodic and chaotic motions occur in the transverse vibrations of the axially accelerating viscoelastic beam

  17. Effect of dynamic plastic deformation on microstructure and annealing behaviour of modified 9Cr-1Mo steel

    DEFF Research Database (Denmark)

    Zhang, Zhenbo; Mishin, Oleg V.; Tao, N. R.

    2015-01-01

    The effect of dynamic plastic deformation on the microstructure of a modified 9Cr - 1Mo steel has been investigated in comparison with the effect of quasi- static compression. It is found that the boundary spacing after dynamic plastic deformation is smaller and the hardness is higher than those...... after quasi- static compression. The microstructure after dynamic plastic deformation is however less stable than the microstructure after quasi- static compression. Annealing at 675 and 700 degrees C leads to structural coarsening and recrystallisation in each sample, but with recrystallisation...... occurring faster in the sample annealed after dynamic plastic deformation. The lower thermal stability of the microstructure produced by dynamic plastic deformation is attributed to a higher driving force for recrystallisation in the dynamically deformed material....

  18. Reducing gait speed affects axial coordination of walking turns.

    Science.gov (United States)

    Forsell, Caroline; Conradsson, David; Paquette, Caroline; Franzén, Erika

    2017-05-01

    Turning is a common feature of daily life and dynamic coordination of the axial body segments is a cornerstone for safe and efficient turning. Although slow walking speed is a common trait of old age and neurological disorders, little is known about the effect of walking speed on axial coordination during walking turns. The aim of this study was to investigate the influence of walking speed on axial coordination during walking turns in healthy elderly adults. Seventeen healthy elderly adults randomly performed 180° left and right turns while walking in their self-selected comfortable pace and in a slow pace speed. Turning velocity, spatiotemporal gait parameters (step length and step time), angular rotations and angular velocity of the head and pelvis, head-pelvis separation (i.e. the angular difference in degrees between the rotation of the head and pelvis) and head-pelvis velocity were analyzed using Wilcoxon signed-rank tests. During slow walking, turning velocity was 15% lower accompanied by shorter step length and longer step time compared to comfortable walking. Reducing walking speed also led to a decrease in the amplitude and velocity of the axial rotation of the head and pelvis as well as a reduced head-pelvis separation and angular velocity. This study demonstrates that axial coordination during turning is speed dependent as evidenced by a more 'en bloc' movement pattern (i.e. less separation between axial segments) at reduced speeds in healthy older adults. This emphasizes the need for matching speed when comparing groups with diverse walking speeds to differentiate changes due to speed from changes due to disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. [Myopia: frequency of lattice degeneration and axial length].

    Science.gov (United States)

    Martín Sánchez, M D; Roldán Pallarés, M

    2001-05-01

    To evaluate the relationship between lattice retinal degeneration and axial length of the eye in different grades of myopia. A sample of 200 eyes from 124 myopic patients was collected by chance. The average age was 34.8 years (20-50 years) and the myopia was between 0.5 and 20 diopters (D). The eyes were grouped according to the degree of refraction defect, the mean axial length of each group (Scan A) and the frequency of lattice retinal degeneration and the relationship between these variables was studied. The possible influence of age on our results was also considered. For the statistical analysis, the SAS 6.07 program with the variance analysis for quantitative variables, and chi(2) test for qualitative variables with a 5% significance were used. A multivariable linear regression model was also adjusted. The highest frequency of lattice retinal degeneration occurred in those myopia patients having more than 15 D, and also in the group of myopia patients between 3 and 6 D, but this did not show statistical significance when compared with the other myopic groups. If the axial length is assessed, a greater frequency of lattice retinal degeneration is also found when the axial length is 25-27 mm and 29-30 mm, which correspond, respectively, to myopias between 3-10 D and more than 15 D. When the multivariable linear regression model was adjusted, the axial length showed the existence of lattice retinal degeneration (beta 0.41 mm; p=0.08) adjusted by the number of diopters (beta 0.38 mm; plattice retinal degeneration was found for myopias with axial eye length between 29-30 mm (more than 15 D), and 25-27 mm (between 3-10 D).

  20. Computing layouts with deformable templates

    KAUST Repository

    Peng, Chi-Han

    2014-07-22

    In this paper, we tackle the problem of tiling a domain with a set of deformable templates. A valid solution to this problem completely covers the domain with templates such that the templates do not overlap. We generalize existing specialized solutions and formulate a general layout problem by modeling important constraints and admissible template deformations. Our main idea is to break the layout algorithm into two steps: a discrete step to lay out the approximate template positions and a continuous step to refine the template shapes. Our approach is suitable for a large class of applications, including floorplans, urban layouts, and arts and design. Copyright © ACM.

  1. Axial Permanent Magnet Generator for Wearable Energy Harvesting

    DEFF Research Database (Denmark)

    Högberg, Stig; Sødahl, Jakob Wagner; Mijatovic, Nenad

    2016-01-01

    An increasing demand for battery-free electronics is evident by the rapid increase of wearable devices, and the design of wearable energy harvesters follows accordingly. An axial permanent magnet generator was designed to harvest energy from human body motion and supplying it to a wearable...... application. The design was approached from an lectromagnetic point of view in this article. Two types of axial flux permanent magnet generators were designed: one with an iron yoke, which is commonly used to reduce the machine volume and demand of permanent magnets, and a second without the iron yoke...

  2. Manufacture of axially insulated large-area diodes

    International Nuclear Information System (INIS)

    Ma Weiyi; Zhou Kungang; Wang Youtian; Zhang Dong; Shan Yusheng; Wang Naiyan

    1999-01-01

    The author describes the design and construction of the axially insulated large-area diodes used in the 'Heaven-1'. The four axially insulated large-area diodes are connected to the 10 ohm pulse transmission lines via the vacuum feed through tubes. The experimental results with the diodes are given. The diodes can steadily work at the voltage of 650 kV, and the diode current density is about 80 A per cm 2 with a pulse width of 220 ns. The electron beams with a total energy of 25 kJ are obtained

  3. Periodicity effects of axial waves in elastic compound rods

    DEFF Research Database (Denmark)

    Nielsen, R. B.; Sorokin, S. V.

    2015-01-01

    Floquet analysis is applied to the Bernoulli-Euler model for axial waves in a periodic rod. Explicit asymptotic formulae for the stop band borders are given and the topology of the stop band pattern is explained. Eigenfrequencies of the symmetric unit cell are determined by the Phase-closure Prin......Floquet analysis is applied to the Bernoulli-Euler model for axial waves in a periodic rod. Explicit asymptotic formulae for the stop band borders are given and the topology of the stop band pattern is explained. Eigenfrequencies of the symmetric unit cell are determined by the Phase...

  4. Buckling localization in a cylindrical panel under axial compression

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2000-01-01

    Localization of an initially periodic buckling pattern is investigated for an axially compressed elastic-plastic cylindrical panel of the type occurring between axial stiffeners on cylindrical shells. The phenomenon of buckling localization and its analogy with plastic flow localization in tensile...... test specimens is discussed in general. For the cylindrical panel, it is shown that buckling localization develops shortly after a maximum load has been attained, and this occurs for a purely elastic panel as well as for elastic-plastic panels. In a case where localization occurs after a load maximum...

  5. Spectral analysis in thin tubes with axial heterogeneities

    KAUST Repository

    Ferreira, Rita

    2015-01-01

    In this paper, we present the 3D-1D asymptotic analysis of the Dirichlet spectral problem associated with an elliptic operator with axial periodic heterogeneities. We extend to the 3D-1D case previous 3D-2D results (see [10]) and we analyze the special case where the scale of thickness is much smaller than the scale of the heterogeneities and the planar coefficient has a unique global minimum in the periodic cell. These results are of great relevance in the comprehension of the wave propagation in nanowires showing axial heterogeneities (see [17]).

  6. A simple approach to the ABJ axial anomaly

    International Nuclear Information System (INIS)

    Horejsi, J.

    1985-01-01

    A very simple semi-quantitative derivation of the Adler-Bell-Jackiw (ABJ) axial anomaly is given, based on an investigation of the absorptive part of the VVA triangle graph and dispersion relations. Essential ingredients of our discussion are: normal Ward identities for the absorptive part of the relevant diagram, dimensional analysis, unitarity, and energy-momentum conservation. An explanation of the physical origin of axial anomaly, proposed in some earlier treatments within such a dispersive framework, is critically examined. In particular, the interpretation of the ABJ anomaly as an analogy of the Lee-Nauenberg effect occurring in the massless limit of spinor electrodynamics is shown to be fallacious

  7. Study on Predicting Axial Load Capacity of CFST Columns

    Science.gov (United States)

    Ravi Kumar, H.; Muthu, K. U.; Kumar, N. S.

    2017-11-01

    This work presents an analytical study and experimental study on the behaviour and ultimate load carrying capacity of axially compressed self-compacting concrete-filled steel tubular columns. Results of tests conducted by various researchers on 213 samples concrete-filled steel tubular columns are reported and present authors experimental data are reported. Two theoretical equations were derived for the prediction of the ultimate axial load strength of concrete-filled steel tubular columns. The results from prediction were compared with the experimental data. Validation to the experimental results was made.

  8. Polycrystal deformation and single crystal deformation: Dislocation structure and flow stress in copper

    DEFF Research Database (Denmark)

    Huang, X.; Borrego, A.; Pantleon, W.

    2001-01-01

    The relation between the polycrystal deformation and single crystal deformation has been studied for pure polycrystalline copper deformed in tension. The dislocation microstructure has been analyzed for grains of different orientation by transmission electron microscopy (TEM) and three types...

  9. Three-axial Fiber Bragg Grating Strain Sensor for Volcano Monitoring

    Science.gov (United States)

    Giacomelli, Umberto; Beverini, Nicolò; Carbone, Daniele; Carelli, Giorgio; Francesconi, Francesco; Gambino, Salvatore; Maccioni, Enrico; Morganti, Mauro; Orazi, Massimo; Peluso, Rosario; Sorrentino, Fiodor

    2017-04-01

    Fiber optic and FBGs sensors have attained a large diffusion in the last years as cost-effective monitoring and diagnostic devices in civil engineering. However, in spite of their potential impact, these instruments have found very limited application in geophysics. In order to study earthquakes and volcanoes, the measurement of crustal deformation is of crucial importance. Stress and strain behaviour is among the best indicators of changes in the activity of volcanoes .. Deep bore-hole dilatometers and strainmeters have been employed for volcano monitoring. These instruments are very sensitive and reliable, but are not cost-effective and their installation requires a large effort. Fiber optic based devices offer low cost, small size, wide frequency band, easier deployment and even the possibility of creating a local network with several sensors linked in an array. We present the realization, installation and first results of a shallow-borehole (8,5 meters depth) three-axial Fiber Bragg Grating (FBG) strain sensor prototype. This sensor has been developed in the framework of the MED-SUV project and installed on Etna volcano, in the facilities of the Serra La Nave astrophysical observatory. The installation siteis about 7 Km South-West of the summit craters, at an elevation of about 1740 m. The main goal of our work is the realization of a three-axial device having a high resolution and accuracy in static and dynamic strain measurements, with special attention to the trade-off among resolution, cost and power consumption. The sensor structure and its read-out system are innovative and offer practical advantages in comparison with traditional strain meters. Here we present data collected during the first five months of operation. In particular, the very clear signals recorded in the occurrence of the Central Italy seismic event of October 30th demonstrate the performances of our device.

  10. Deformations of the Almheiri-Polchinski model

    Energy Technology Data Exchange (ETDEWEB)

    Kyono, Hideki; Okumura, Suguru; Yoshida, Kentaroh [Department of Physics, Kyoto University, Kitashirakawa Oiwake-cho, Kyoto 606-8502 (Japan)

    2017-03-31

    We study deformations of the Almheiri-Polchinski (AP) model by employing the Yang-Baxter deformation technique. The general deformed AdS{sub 2} metric becomes a solution of a deformed AP model. In particular, the dilaton potential is deformed from a simple quadratic form to a hyperbolic function-type potential similarly to integrable deformations. A specific solution is a deformed black hole solution. Because the deformation makes the spacetime structure around the boundary change drastically and a new naked singularity appears, the holographic interpretation is far from trivial. The Hawking temperature is the same as the undeformed case but the Bekenstein-Hawking entropy is modified due to the deformation. This entropy can also be reproduced by evaluating the renormalized stress tensor with an appropriate counter-term on the regularized screen close to the singularity.

  11. Dynamical attraction to stable processes

    OpenAIRE

    Fisher, Albert M.; Talet, Marina

    2012-01-01

    We apply dynamical ideas within probability theory, proving an almost-sure invariance principle in log density for stable processes. The familiar scaling property (self-similarity) of the stable process has a stronger expression, that the scaling flow on Skorokhod path space is a Bernoulli flow. We prove that typical paths of a random walk with i.i.d. increments in the domain of attraction of a stable law can be paired with paths of a stable process so that, after applying a non-random regula...

  12. Deformations of the generalised Picard bundle

    International Nuclear Information System (INIS)

    Biswas, I.; Brambila-Paz, L.; Newstead, P.E.

    2004-08-01

    Let X be a nonsingular algebraic curve of genus g ≥ 3, and let Mξ denote the moduli space of stable vector bundles of rank n ≥ 2 and degree d with fixed determinant ξ over X such that n and d are coprime. We assume that if g = 3 then n ≥ 4 and if g = 4 then n ≥ 3, and suppose further that n 0 , d 0 are integers such that n 0 ≥ 1 and nd 0 + n 0 d > nn 0 (2g - 2). Let E be a semistable vector bundle over X of rank n 0 and degree d 0 . The generalised Picard bundle W ξ (E) is by definition the vector bundle over M ξ defined by the direct image p M ξ *(U ξ x p X * E) where U ξ is a universal vector bundle over X x M ξ . We obtain an inversion formula allowing us to recover E from W ξ (E) and show that the space of infinitesimal deformations of W ξ (E) is isomorphic to H 1 (X, End(E)). This construction gives a locally complete family of vector bundles over M ξ parametrised by the moduli space M(n 0 ,d 0 ) of stable bundles of rank n 0 and degree d 0 over X. If (n 0 ,d 0 ) = 1 and W ξ (E) is stable for all E is an element of M(n 0 ,d 0 ), the construction determines an isomorphism from M(n 0 ,d 0 ) to a connected component M 0 of a moduli space of stable sheaves over M ξ . This applies in particular when n 0 = 1, in which case M 0 is isomorphic to the Jacobian J of X as a polarised variety. The paper as a whole is a generalisation of results of Kempf and Mukai on Picard bundles over J, and is also related to a paper of Tyurin on the geometry of moduli of vector bundles. (author)

  13. Deformable 4DCT lung registration with vessel bifurcations

    International Nuclear Information System (INIS)

    Hilsmann, A.; Vik, T.; Kaus, M.; Franks, K.; Bissonette, J.P.; Purdie, T.; Beziak, A.; Aach, T.

    2007-01-01

    In radiotherapy planning of lung cancer, breathing motion causes uncertainty in the determination of the target volume. Image registration makes it possible to get information about the deformation of the lung and the tumor movement in the respiratory cycle from a few images. A dedicated, automatic, landmark-based technique was developed that finds corresponding vessel bifurcations. Hereby, we developed criteria to characterize pronounced bifurcations for which correspondence finding was more stable and accurate. The bifurcations were extracted from automatically segmented vessel trees in maximum inhale and maximum exhale CT thorax data sets. To find corresponding bifurcations in both data sets we used the shape context approach of Belongie et al. Finally, a volumetric lung deformation was obtained using thin-plate spline interpolation and affine registration. The method is evaluated on 10 4D-CT data sets of patients with lung cancer. (orig.)

  14. Large Deformation Mechanics of Plasma Membrane Chained Vesicles in Cells

    Science.gov (United States)

    Kosawada, Tadashi; Sanada, Kouichi; Takano, Tetsuo

    The clathrin-coated pits, vesicles and chained vesicles on the inner surface of the plasma membrane facilitate the cell to transport specific extracellular macromolecules. This cellular process is strongly involved with large mechanical deformations of the plasma membrane accompanied by changes in membrane curvature. The assembly of the clathrin coat is thought to provide curvature into the membrane. Hence, effects of in-plane shear elasticity due to these coat structure may be significant on the vesicular mechanics. In this study, large deformation mechanics of plasma membrane chained vesicles in cells have been formulated based on minimization of bending and in-plane shear strain energy of the membrane. Effects of outer surrounding cytoplasmic flat membrane upon mechanically stable shapes of the vesicles were revealed, while effects of in-plane shear elasticity were partly discussed.

  15. The effect of mechanical restraint on the deformation of Zircaloy cladding

    International Nuclear Information System (INIS)

    Jones, P.M.; Haste, T.J.

    1980-10-01

    Zircaloy cladding, deformed at temperatures postulated for loss-of-coolant accidents, can exhibit considerable ductility. The actual circumferential strain is governed by the temperature uniformity around the rod during the time at which the major part of the deformation occurs. If the bulges in neighbouring rods in a multi-rod array touch before rupture, and the array is large enough for the outer rods to restrain bulges rather than be pushed away by them, then the stress in such bulges drops. However the stress in adjacent axial regions of the cladding which have not contacted remains high and these continue to strain until they also interact, thus propagating the bulging axially. Meanwhile the non-contacted portions of the interacting bulges continue to strain slowly into the remaining sub-channels. Illustrative calculations suggest that the mechanical restraint of bulging cladding will only be effective in increasing sub-channel blockage when the failure strains are greater than 60-70%. This may occur with temperature differences between neighbouring rods of 10-25 0 C if the deformation process is thermally stabilised. (author)

  16. [Angle-stable fixation of intramedullary nails using the Angular Stable Locking System® (ASLS)].

    Science.gov (United States)

    Höntzsch, D; Blauth, M; Attal, R

    2011-12-01

    Greater stability in intramedullary osteosynthesis using angle-stable fixation with intramedullary nails and proximal locking screws. A novel screw-and-sleeve system (ASLS®, Synthes GmbH, Oberdorf, Switzerland) is applied using normal cannulated nails. Decisions can be made intraoperatively. This technology widens the range of indications for intramedullary nailing: The smaller and less stable the fragment requiring fixation, the greater the indication for angular stable fixation of the proximal and/or distal fragment. Femoral, tibial and humeral fractures, intramedullary osteosynthesis in osteoporotic bone and ante- and retrograde nailing. Particularly in the case of retrograde nailing, sustained prevention of nail toggling is achieved. None. Drill with the first drill bit, which has the same core diameter as the screw shaft. Drill the cortex to the external diameter of the sleeve. Place the sleeve on the tip of the screw. The screw-sleeve combination is then advanced through the larger near hole until the sleeve-covered screw tip sits in the locking hole of the intramedullary fixation nail. Advance the screw. As the screw diameter becomes larger, the sleeve expands resulting in an angular stable locking effect. The screw is then advanced until the head of the screw sits on the exposed surface of the cortex. The hole is filled with the expanded part of the screw shaft beneath the screw head. The necessary 1-3 turns are cut by the self-tapping flute on the screw. According to experience to date, this form of angle-stable fixation enables earlier and/or greater partial mobilization or earlier full mobilization. In all other respects, the guidelines for aftercare in intramedullary nailing apply. A multi-center pilot study has shown the technique to be reproducible and simple. There have been no complications using this technique to date. Biomechanical laboratory studies have demonstrated that stability with respect to axial and torsional loading is statically and

  17. Improvement of Functional Properties by Sever Plastic Deformation on Parts of Titanium Biomaterials

    Science.gov (United States)

    Czán, Andrej; Babík, Ondrej; Daniš, Igor; Martikáň, Pavol; Czánová, Tatiana

    2017-12-01

    Main task of materials for invasive implantology is their biocompatibility with the tissue but also requirements for improving the functional properties of given materials are increasing constantly. One of problems of materials biocompatibility is the impossibility to improve of functional properties by change the percentage of the chemical elements and so it is necessary to find other innovative methods of improving of functional properties such as mechanical action in the form of high deformation process. This paper is focused on various methods of high deformation process such as Equal Channel Angular Pressing (ECAP) when rods with record strength properties were obtained.The actual studies of the deformation process properties as tri-axial compress stress acting on workpiece with high speed of deformation shows effects similar to results obtained using the other methods, but in lower levels of stress. Hydrostatic extrusion (HE) is applying for the purpose of refining the structure of the commercially pure titanium up to nano-scale. Experiments showed the ability to reduce the grain size below 100 nm. Due to the significant change in the performance of the titanium materials by severe plastic deformation is required to identify the processability of materials with respect to the identification of created surfaces and monitoring the surface integrity, where the experimental results show ability of SPD technologies application on biomaterials.

  18. Impact-induced frictional melting in ordinary chondrites: A mechanism for deformation, darkening, and vein formation

    Science.gov (United States)

    van der Bogert, C. H.; Schultz, P. H.; Spray, J. G.

    2003-10-01

    High speed friction experiments have been performed on the ordinary chondrites El Hammami (H5, S2) and Sahara 97001 (L6, S3) using an axial friction-welding apparatus. Each sample was subjected to a strain rate of 103 to 104 s-1, which generated 250 to 500 μm-deep darkened zones on each sample cube. Thin section analyses reveal that the darkened areas are composed of silicate glass and mineral fragments intermingled with dispersed submicron-size FeNi and FeS blebs. Fracturing of mineral grains and the formation of tiny metallic veins define the extent of deformation beyond the darkened shear zone. These features are not present in the original meteorites. The shear zones and tiny veins are quite similar to certain vein systems seen in naturally deformed ordinary chondrites. The experiments show that shock deformation is not required for the formation of melt veins and darkening in ordinary chondrites. Therefore, the presence of melt veins and darkening does not imply that an ordinary chondrite has undergone severe shock deformation. In fact, high strain rate deformation and frictional melting are especially important for the formation of veins at low shock pressures.

  19. Topography and structural heterogeneities in surface ground deformation: a simulation test for Somma-Vesuvius volcano

    Science.gov (United States)

    Tammaro, Umberto; Riccardi, Umberto; Romano, Vittorio; Meo, Michele; Capuano, Paolo

    2017-04-01

    Through a 3D finite element code we simulate, the deformation of Somma-Vesuvius volcano caused by some overpressure sources. Under the assumption of linear elastic isotropic material behavior, the volcano deformation sources are located at various depths and their geometry (shape and lateral extension) is mainly constrained by the results of recent seismic tomography studies. These simulations have the objective to inquire about the influence of topography and structural heterogeneity on ground deformation. Structural heterogeneities have been modeled in terms of dynamical elastic parameters (Young's modulus) accounting for previous seismic tomography and gravity studies. Topography of Somma-Vesuvius is taken into account, using a digital terrain model. The main outcomes of this study is a strong deviation from axially symmetric pattern of the displacement field, which is quietly unaccounted by simplistic Mogi modeling in homogeneous medium with simplified topography. These results demonstrate that real topography and structural heterogeneities are key factors controlling the pattern of ground deformations, i.e. one of the most relevant problem in volcano monitoring. Moreover, an improved knowledge of deformation patterns can significantly help in the location of monitoring sensors as well as in the design of an efficient geodetic network.

  20. Spatiotemporal deformations of reflectionless potentials

    Science.gov (United States)

    Horsley, S. A. R.; Longhi, S.

    2017-08-01

    Reflectionless potentials for classical or matter waves represent an important class of scatteringless systems encountered in different areas of physics. Here we mathematically demonstrate that there is a family of non-Hermitian potentials that, in contrast to their Hermitian counterparts, remain reflectionless even when deformed in space or time. These are the profiles that satisfy the spatial Kramers-Kronig relations. We start by considering scattering of matter waves for the Schrödinger equation with an external field, where a moving potential is observed in the Kramers-Henneberger reference frame. We then generalize this result to the case of electromagnetic waves, by considering a slab of reflectionless material that both is scaled and has its center displaced as an arbitrary function of position. We analytically and numerically demonstrate that the backscattering from these profiles remains zero, even for extreme deformations. Our results indicate the supremacy of non-Hermitian Kramers-Kronig potentials over reflectionless Hermitian potentials in keeping their reflectionless property under deformation and could find applications to, e.g., reflectionless optical coatings of highly deformed surfaces based on perfect absorption.

  1. Deformable Models for Eye Tracking

    DEFF Research Database (Denmark)

    Vester-Christensen, Martin; Leimberg, Denis; Ersbøll, Bjarne Kjær

    2005-01-01

    A deformable template method for eye tracking on full face images is presented. The strengths of the method are that it is fast and retains accuracy independently of the resolution. We compare the me\\$\\backslash\\$-thod with a state of the art active contour approach, showing that the heuristic...

  2. Simulation of rock deformation behavior

    Directory of Open Access Journals (Sweden)

    Я. И. Рудаев

    2016-12-01

    Full Text Available A task of simulating the deformation behavior of geomaterials under compression with account of over-extreme branch has been addressed. The physical nature of rock properties variability as initially inhomogeneous material is explained by superposition of deformation and structural transformations of evolutionary type within open nonequilibrium systems. Due to this the description of deformation and failure of rock is related to hierarchy of instabilities within the system being far from thermodynamic equilibrium. It is generally recognized, that the energy function of the current stress-strain state is a superposition of potential component and disturbance, which includes the imperfection parameter accounting for defects not only existing in the initial state, but also appearing under load. The equation of state has been obtained by minimizing the energy function by the order parameter. The imperfection parameter is expressed through the strength deterioration, which is viewed as the internal parameter of state. The evolution of strength deterioration has been studied with the help of Fokker – Planck equation, which steady form corresponds to rock statical stressing. Here the diffusion coefficient is assumed to be constant, while the function reflecting internal sliding and loosening of the geomaterials is assumed as an antigradient of elementary integration catastrophe. Thus the equation of state is supplemented with a correlation establishing relationship between parameters of imperfection and strength deterioration. While deformation process is identified with the change of dissipative media, coupled with irreversible structural fluctuations. Theoretical studies are proven with experimental data obtained by subjecting certain rock specimens to compression.

  3. Cleft deformities (lip and palate)

    African Journals Online (AJOL)

    dell

    Background: Cleft deformities (lip and palate) have been reported to be the most common congenital craniofacial anomaly in several settings. In Uganda, though two previous studies were conducted to determine the incidence of cleft lip and palate, the estimates obtained from those studies may not be precise given the ...

  4. Deformations of topological open strings

    NARCIS (Netherlands)

    Hofman, C.; Ma, Whee Ky

    Deformations of topological open string theories are described, with an emphasis on their algebraic structure. They are encoded in the mixed bulk-boundary correlators. They constitute the Hochschild complex of the open string algebra - the complex of multilinear maps on the boundary Hilbert space.

  5. Deformation mechanisms of nanotwinned Al

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinghang [Texas A & M Univ., College Station, TX (United States)

    2016-11-10

    The objective of this project is to investigate the role of different types of layer interfaces on the formation of high density stacking fault (SF) in Al in Al/fcc multilayers, and understand the corresponding deformation mechanisms of the films. Stacking faults or twins can be intentionally introduced (via growth) into certain fcc metals with low stacking fault energy (such as Cu, Ag and 330 stainless steels) to achieve high strength, high ductility, superior thermal stability and good electrical conductivity. However it is still a major challenge to synthesize these types of defects into metals with high stacking fault energy, such as Al. Although deformation twins have been observed in some nanocrystalline Al powders by low temperature, high strain rate cryomilling or in Al at the edge of crack tip or indentation (with the assistance of high stress intensity factor), these deformation techniques typically introduce twins sporadically and the control of deformation twin density in Al is still not feasible. This project is designed to test the following hypotheses: (1) Certain type of layer interfaces may assist the formation of SF in Al, (2) Al with high density SF may have deformation mechanisms drastically different from those of coarse-grained Al and nanotwinned Cu. To test these hypotheses, we have performed the following tasks: (i) Investigate the influence of layer interfaces, stresses and deposition parameters on the formation and density of SF in Al. (ii) Understand the role of SF on the deformation behavior of Al. In situ nanoindentation experiments will be performed to probe deformation mechanisms in Al. The major findings related to the formation mechanism of twins and mechanical behavior of nanotwinned metals include the followings: 1) Our studies show that nanotwins can be introduced into metals with high stacking fault energy, in drastic contrast to the general anticipation. 2) We show two strategies that can effectively introduce growth twins in

  6. Redesigning axial-axial (biaxial) cruciform specimens for very high cycle fatigue ultrasonic testing machines.

    Science.gov (United States)

    Montalvão, Diogo; Wren, Andrew

    2017-11-01

    The necessity to increase performances in terms of lifetime and security in mechanical components or structures is the motivation for intense research in fatigue. Applications range from aeronautics to medical devices. With the development of new materials, there is no longer a fatigue limit in the classical sense, where it was accepted that the fatigue limit is the stress level such that there is no fracture up to 1E7 cycles. The recent development of ultrasonic testing machines where frequencies can go as high as 20 kHz or over enabled tests to be extended to ranges larger than 1E9 in just a few days. This area of studies is now known as Very High Cycle Fatigue (VHCF). On the other hand, most of the existing test equipment in the market for both classical and VHCF are uniaxial test machines. However, critical components used in Engineering applications are usually subjected to complex multi-axial loading conditions. In this paper, it is presented the methodology to redesigning existing cruciform test specimens that can be used to create an in-plane biaxial state of stress when used in 'uniaxial' VHCF ultrasonic testing machines (in this case, the term 'uniaxial' is used not because of the state of stress created at the centre of the specimen, but because of the direction at which the load is applied). The methodology is explained in such a way that it can be expanded to other existing designs, namely cruciform designs, that are not yet used in VHCF. Also, although the approach is presented in simple and logical terms, it may not be that obvious for those who have a more focused approach on fatigue rather than on modal analysis. It is expected that by contributing to bridging the gap between the sciences of modal analysis and fatigue, this research will help and encourage others exploiting new capabilities in VHCF.

  7. Treatment of hallux valgus deformity.

    Science.gov (United States)

    Fraissler, Lukas; Konrads, Christian; Hoberg, Maik; Rudert, Maximilian; Walcher, Matthias

    2016-08-01

    Hallux valgus deformity is a very common pathological condition which commonly produces painful disability. It is characterised as a combined deformity with a malpositioning of the first metatarsophalangeal joint caused by a lateral deviation of the great toe and a medial deviation of the first metatarsal bone.Taking the patient's history and a thorough physical examination are important steps. Anteroposterior and lateral weight-bearing radiographs of the entire foot are crucial for adequate assessment in the treatment of hallux valgus.Non-operative treatment of the hallux valgus cannot correct the deformity. However, insoles and physiotherapy in combination with good footwear can help to control the symptoms.There are many operative techniques for hallux valgus correction. The decision on which surgical technique is used depends on the degree of deformity, the extent of degenerative changes of the first metatarsophalangeal joint and the shape and size of the metatarsal bone and phalangeal deviation. The role of stability of the first tarsometatarsal joint is controversial.Surgical techniques include the modified McBride procedure, distal metatarsal osteotomies, metatarsal shaft osteotomies, the Akin osteotomy, proximal metatarsal osteotomies, the modified Lapidus fusion and the hallux joint fusion. Recently, minimally invasive percutaneous techniques have gained importance and are currently being evaluated more scientifically.Hallux valgus correction is followed by corrective dressings of the great toe post-operatively. Depending on the procedure, partial or full weight-bearing in a post-operative shoe or cast immobilisation is advised. Post-operative radiographs are taken in regular intervals until osseous healing is achieved. Cite this article: Fraissler L, Konrads C, Hoberg M, Rudert M, Walcher M. Treatment of hallux valgus deformity. EFORT Open Rev 2016;1:295-302. DOI: 10.1302/2058-5241.1.000005.

  8. Supersymmetric axial anomalies and the Wess-Zumino action

    International Nuclear Information System (INIS)

    Harada, K.; Shizuya, K.

    1988-01-01

    We derive, by an algebraic method, a manifestly supersymmetric extension of Bardeen's minimal form of axial anomalies, which obeys the Wess-Zumino consistency condition. The left-right symmetric form of the anomalies is also obtained by a reduction procedure. We construct the supersymmetric Wess-Zumino effective action and study its low-energy features. (orig.)

  9. Dynamic Response of Axially Loaded Euler-Bernoulli Beams

    DEFF Research Database (Denmark)

    Bayat, M.; Barari, Amin; Shahidi, M.

    2011-01-01

    The current research deals with application of a new analytical technique called Energy Balance Method (EBM) for a nonlinear problem. Energy Balance Method is used to obtain the analytical solution for nonlinear vibration behavior of Euler-Bernoulli beams subjected to axial loads. Analytical...

  10. Axial Torsion of Gangrenous Meckel's Diverticulum Causing Small ...

    African Journals Online (AJOL)

    dividing the band. Resection and anastomosis of the small bowel including the MD was performed. We hereby report a rare and unusual complication of a MD. Although treatment outcome is generally good, pre-operative diagnosis is often difficult. Key words: Axial torsion, Meckel's diverticulum, small bowel obstruction.

  11. A cylindrical drift chamber with azimuthal and axial position readout

    Energy Technology Data Exchange (ETDEWEB)

    Bar-Yam, Z.; Cummings, J.P.; Dowd, J.P.; Eugenio, P.; Hayek, M.; Kern, W.; King, E.; Shenhav, N.; Chung, S.U.; Hackenburg, R.W.; Olchanski, C.; Weygand, D.P.; Willutzki, H.J.; Brabson, B.B.; Crittenden, R.R.; Dzierba, A.R.; Gunter, J.; Lindenbusch, R.; Rust, D.R.; Scott, E.; Smith, P.T.; Sulanke, T.; Teige, S.; Denisov, S.; Dushkin, A.; Kochetkov, V.; Lipaev, V.; Popov, A.; Shein, I.; Soldatov, A.; Anoshina, E.V.; Bodyagin, V.A.; Demianov, A.I.; Gribushin, A.M.; Kodolova, O.L.; Korotkikh, V.L.; Kostin, M.A.; Ostrovidov, A.I.; Sarycheva, L.I.; Sinev, N.B.; Vardanyan, I.N.; Yershov, A.A.; Adams, T.; Bishop, J.M.; Cason, N.M.; Sanjari, A.H.; LoSecco, J.M.; Manak, J.J.; Shephard, W.D.; Stienike, D.L.; Taegar, S.A.; Thompson, D.R.; Brown, D.S.; Pedlar, T.; Seth, K.K.; Wise, J.; Zhao, D.; Adams, G.S.; Napolitano, J.; Nozar, M.; Smith, J.A.; Witkowski, M. [Massachusetts Univ., North Dartmouth, MA (United States)]|[Brookhaven National Laboratory, Upton, L.I., NY 11973 (United States)]|[Indiana University, Bloomington, IN 47405 (United States)]|[Institute for High Energy Physics, Protvino (Russian Federation)]|[Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation)]|[University of Notre Dame, Notre Dame, IN 46556 (United States)]|[Northwestern University, Evanston, IL 60208 (United States)]|[Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    1997-02-21

    A cylindrical multiwire drift chamber with axial charge-division has been constructed and used in experiment E852 at Brookhaven National Laboratory. It serves as a trigger element and as a tracking device for recoil protons in {pi}{sup -}p interactions. We describe the chamber`s design considerations, details of its construction, electronics, and performance characteristics. (orig.).

  12. Axial-Gap Induction Motor For Levitated Specimens

    Science.gov (United States)

    Sridharan, Govind; Rhim, Won-Kyu; Barber, Dan; Chung, Sang

    1992-01-01

    Motor does not obscure view of specimen. Axial-gap induction motor applies torque to rotate electrostatically or electromagnetically levitated specimen of metal. Possible applications include turning specimens for uniform heating under focused laser beams and obtaining indirect measurements of resistivities or of surface tensions in molten specimens.

  13. On aspects of vibration of axially moving continua

    NARCIS (Netherlands)

    Hageraats-Ponomareva, S.

    2009-01-01

    In axially moving structures like conveyor belt systems, magnetic tapes, and so on, vibrations occur due to the presence of different kinds of imperfections in the systems. For these structures internal resonances can lead to severe vibrations. Resonance free conveyor belt systems can be constructed

  14. Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

    African Journals Online (AJOL)

    2017-12-05

    Dec 5, 2017 ... variously described as determined by the ocular biometric variables. There have been many studies on the relationship between refractive error and ocular axial length (AL), anterior chamber depth, corneal radius of curvature (CR), keratometric readings as well as other ocular biometric variables such as ...

  15. Solution of the gauge identities in the axial gauge

    International Nuclear Information System (INIS)

    Delbourgo, R.

    1981-01-01

    Starting from the spectral representation of the two-point functions in the axial gauge, the gauge identities are solved so as to express the higher-point Green functions linearly in terms of the two-point spectral function. The four-point functions are an important input for investigations of scalar electrodynamics and vector chromodynamics based on the gauge technique. (author)

  16. 3-D Simulation of Vertical-Axial Tidal Current Turbine

    Directory of Open Access Journals (Sweden)

    Zhiyang Zhang

    2016-12-01

    Full Text Available Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.

  17. View of the Axial Field Spectrometer (R807)

    CERN Multimedia

    1980-01-01

    In this view of the Axial Field Spectrometer at I8, the vertical uranium/scintillator hadron calorimeter (just left of centre) is retracted to give access to the cylindrical central drift chamber. The yellow iron structure served as a filter to identify muons, with MWPCs and the array of Cherenkov counters to the right.

  18. Landforms along transverse faults parallel to axial zone of folded ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 126; Issue 1. Landforms along transverse faults parallel to axial zone of folded mountain front, north-eastern Kumaun Sub-Himalaya, India. Khayingshing ... Keywords. Himalayan Frontal Thrust; outer Kumaun Himalaya; transverse structure; folded mountain front.

  19. sizing of wind powered axial flux permanent magnet alternator using

    African Journals Online (AJOL)

    user

    2016-10-04

    Oct 4, 2016 ... Using analytical calculations, the design parameters of the alternator's main dimensions were obtained in a ... SIZING OF WIND POWERED AXIAL FLUX PERMANENT MAGNET ALTERNATOR USING ANALYTICAL APPROACH,. A. O. Otuoze, et al .... then be expressed as. Equation (7) can be re-written as.

  20. Evaluation of electromagnetic shielding effectiveness of multi-axial ...

    Indian Academy of Sciences (India)

    Abstract. The usage of electrical and electronic equipments has been increasing in daily life, which has a potential hazardous impact on humans and other living organisms. In this paper, multi-axial fabrics containing steel yarns and carbon filaments, and their polyester (PES) resin-reinforced composites have been ...

  1. Ocular Axial Length and Keratometry Readings of Normal Eyes in ...

    African Journals Online (AJOL)

    Aim: To provide average axial length and keratometry readings in healthy eyes of people in Rivers and surrounding states in southern Nigeria. This may guide the purchase of intraocular lens in the study area. Materials and methods: Four hundred consecutive patients with 800 non-cataractous eyes attending the eye clinic ...

  2. Axial drive to nonlinear flow between rotating cylinders

    Science.gov (United States)

    Ashrafi, Nariman; Hazbavi, Abbas

    2014-02-01

    Stability of pseudoplastic rotational flow between cylinders in presence of an independent axial component is investigated. The fluid is assumed to follow the Carreau model and mixed boundary conditions are imposed. The conservation of mass and momentum equations give rise to a four-dimensional low-order dynamical system, including additional nonlinear terms in the velocity components originated from the shear-dependent viscosity. In absence of the axial flow, as the pseudoplasticity effects increases, the purely-azimuthal base flow loses its stability to the vortex structure at a lower critical Taylor number. Emergence of the vortices corresponds to the onset of a supercritical bifurcation also present in the flow of a linear fluid. However, unlike the Newtonian case, pseudoplastic Taylor vortices lose their stability as the Taylor number reaches a second critical number corresponding to the onset of a Hopf bifurcation. Existence of an axial flow induced by a pressure gradient appears to further advance each critical point on the bifurcation diagram. In continuation, complete flow field together with viscosity maps is analyzed for different flow scenarios. Through evaluation of the Lyapunov exponent, flow stability and temporal behavior of the system for cases with and without axial flow are brought to attention.

  3. Employing a tri-axial accelerometer for estimating energy ...

    African Journals Online (AJOL)

    The Tritrac-R3D, a portable tri-axial accelerometer, was assessed for its ability to estimate energy expenditure during simulated load carrying activities. The Tritrac data were compared to metabolic data collected simultaneously by a MetaMax ergospirometry system while ten, healthy male subjects (aged 20.7 ±1.4 years) ...

  4. Numerical simulation of breakup and detachment of an axially ...

    Indian Academy of Sciences (India)

    Kishore Singh Patel

    Abstract. The extensional, breakup and detachment dynamics of an axially stretching Newtonian liquid bridge are investigated numerically with a dynamic domain multiphase incompressible flow solver. The mul- tiphase flow solver employs a Cahn–Hilliard phase field model to describe the evolution of the diffuse interface.

  5. Computation of the lateral and axial point spread functions in ...

    Indian Academy of Sciences (India)

    ... confocal scanning microscopes for the above-mentioned amplitude filters. These results of axial and lateral irradiances are graphically represented by constructing a computer program using MATLAB. The obtained results are compared with that obtained in case of circular, annular, and Martinez-Corral apodized aperture ...

  6. Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... Aim/Background: Associations between axial length (AL) to corneal radius of curvature (CR) ratio and refractive status in a healthy Nigerian adult population were studied. Materials and Methods: Healthy students and members of staff of Obafemi Awolowo Teaching Hospitals Complex, Ile-Ife, South West ...

  7. Axial heterogeneous core concept applied for super phoenix reactor

    International Nuclear Information System (INIS)

    Batista, J.L.; Renke, C.A.C.; Waintraub, M.; Santos Bastos, W. dos; Brito Aghina, L.O. de.

    1991-11-01

    Always maintaining the current design rules, this paper presents a parametric study on the type of axial heterogeneous core concept (CHA), utilizing a core of fast reactor Super Phenix type, reaching a maximum thermal burnup rate of 150000 M W d/t and being managed in single batch. (author)

  8. Fission gas retention and axial expansion of irradiated metallic fuel

    International Nuclear Information System (INIS)

    Fenske, G.R.; Emerson, J.E.; Savoie, F.E.; Johanson, E.W.

    1986-05-01

    Out-of-reactor experiments utilizing direct electrical heating and infrared heating techniques were performed on irradiated metallic fuel. The results indicate accelerated expansion can occur during thermal transients and that the accelerated expansion is driven by retained fission gases. The results also demonstrate gas retention and, hence, expansion behavior is a function of axial position within the pin

  9. Evaluation of electromagnetic shielding effectiveness of multi-axial ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... ... Lecture Workshops · Refresher Courses · Symposia. Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Evaluation of electromagnetic shielding effectiveness of multi-axial fabrics and their reinforced PES composites. RAMAZAN ERDEM. Volume 39 Issue 4 August 2016 pp 963-970 ...

  10. Evaluation of electromagnetic shielding effectiveness of multi-axial ...

    Indian Academy of Sciences (India)

    The usage of electrical and electronic equipments has been increasing in daily life, which has a potential hazardous impact on humans and other living organisms. In this paper, multi-axial fabrics containing steel yarns and carbon filaments, and their polyester (PES) resin-reinforced composites have been prepared for ...

  11. Elevated temperature axial and torsional fatigue behavior of Haynes 188

    Science.gov (United States)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1995-01-01

    The results are reported for high-temperature axial and torsional low-cycle fatigue experiments performed at 760 C in air on thin-walled tubular specimens of Haynes 188, a wrought cobalt-based superalloy. Data are also presented for mean coefficient of thermal expansion, elastic modulus, and shear modulus at various temperatures from room to 1000 C, and monotonic and cyclic stress-strain curves in tension and in shear at 760 C. This data set is used to evaluate several multiaxial fatigue life models (most were originally developed for room temperature multiaxial life prediction) including von Mises equivalent strain range (ASME Boiler and Pressure Code), Manson-Halford, modified multiaxiality factor (proposed in this paper), modified Smith-Watson-Topper, and Fatemi-Socie-Kurath. At von Mises equivalent strain ranges (the torsional strain range divided by the square root of 3, taking the Poisson's ratio to be 0.5), torsionally strained specimens lasted, on average, factors of 2 to 3 times longer than axially strained specimens. The modified multiaxiality factor approach shows promise as a useful method of estimating torsional fatigue life from axial fatigue data at high temperatures. Several difficulties arose with the specimen geometry and extensometry used in these experiments. Cracking at extensometer probe indentations was a problem at smaller strain ranges. Also, as the largest axial and torsional strain range fatigue tests neared completion, a small amount of specimen buckling was observed.

  12. first principles derivation of a stress function for axially symmetric

    African Journals Online (AJOL)

    HOD

    found to be identical with the Love stress function. The stress function was then applied to solve the axially symmetric problem of finding the stress fields, strain fields and displacement fields in the semi-infinite linear elastic, isotropic homogeneous medium subject to a point load P acting at the origin of coordinates also ...

  13. Kinetics and equilibria for the axial ligation of bromomethyl (aqua ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 121; Issue 6. Kinetics and equilibria for the axial ligation of bromomethyl (aqua)cobaloxime with pyridines - Isolation characterization and DNA binding. Kotha Laxma Reddy K Ashwini Kumar N Ravi Kumar Reddy Penumaka Nagababu A Panasa Reddy S ...

  14. Axial anomaly and magnetism of nuclear and quark matter

    Science.gov (United States)

    Son, D. T.; Stephanov, M. A.

    2008-01-01

    We consider the response of the QCD ground state at finite baryon density to a strong magnetic field B. We point out the dominant role played by the coupling of neutral Goldstone bosons, such as π0, to the magnetic field via the axial triangle anomaly. We show that, in vacuum, above a value of B˜mπ2/e, a metastable object appears—the π0 domain wall. Because of the axial anomaly, the wall carries a baryon number surface density proportional to B. As a result, for B≳1019G a stack of parallel π0 domain walls is energetically more favorable than nuclear matter at the same density. Similarly, at higher densities, somewhat weaker magnetic fields of order B≳1017 1018G transform the color-superconducting ground state of QCD into new phases containing stacks of axial isoscalar (η or η') domain walls. We also show that a quark-matter state known as “Goldstone current state,” in which a gradient of a Goldstone field is spontaneously generated, is ferromagnetic due to the axial anomaly. We estimate the size of the fields created by such a state in a typical neutron star to be of order 1014 1015G.

  15. Modelling the cardiac transverse-axial tubular system

    Czech Academy of Sciences Publication Activity Database

    Pásek, Michal; Šimurda, J.; Christé, G.; Orchard, C.

    2008-01-01

    Roč. 96, - (2008), s. 226-246 ISSN 0079-6107 Institutional research plan: CEZ:AV0Z20760514 Keywords : cardiac cell * transverse-axial tubular system * quantitative modelling Subject RIV: BO - Biophysics Impact factor: 6.388, year: 2008

  16. Comparison of design methods for axially loaded buckets in sand

    DEFF Research Database (Denmark)

    Vaitkunaite, Evelina; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2015-01-01

    A study of the present knowledge about the bucket resistance for axial loading was performed considering analytical and numerical design methods as well as physical models. A case study was performed with two bucket foundations of equal diameter, but different skirt lengths installed in dense san...

  17. Axial and focal-plane diffraction catastrophe integrals

    International Nuclear Information System (INIS)

    Berry, M V; Howls, C J

    2010-01-01

    Exact expressions in terms of Bessel functions are found for some of the diffraction catastrophe integrals that decorate caustics in optics and mechanics. These are the axial and focal-plane sections of the elliptic and hyperbolic umbilic diffraction catastrophes, and symmetric elliptic and hyperbolic unfoldings of the X 9 diffraction catastrophes. These representations reveal unexpected relations between the integrals.

  18. Atlanto-axial instability in rheumatoid arthritis: a review | Omar ...

    African Journals Online (AJOL)

    Objectives: The purpose of this literature review is to identify common lesions present in the rheumatoid neck with specific emphasis to atlanto-axial instability, review its clinical presentation, imaging findings and management. Study design: A review of the English medical literature was done with focus on recent studies ...

  19. Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

    African Journals Online (AJOL)

    Aim/Background: Associations between axial length (AL) to corneal radius of curvature (CR) ratio and refractive status in a healthy Nigerian adult population were studied. Materials and Methods: Healthy students and members of staff of Obafemi Awolowo Teaching Hospitals Complex, Ile‑Ife, South West Nigeria, free of ...

  20. Ocular Axial Length Measurement Among Normal Adults Using ...

    African Journals Online (AJOL)

    2017-07-26

    Jul 26, 2017 ... Background/Introduction: Macrophthalmia and microphthalmia are cardinal signs of many orbito-ocular and systemic diseases which are seen in northern Nigeria. Some cases of refractive error may also be directly related to the ocular axial length (AL). The need for an imaging parameter that will aid their ...

  1. Axial Torsion of Gangrenous Meckel's Diverticulum Causing Small ...

    African Journals Online (AJOL)

    Meckel's diverticulum (MD) is a commonly encountered congenital anomaly of the small intestine. We report an extremely unusual case of an axially torted, gangrenous MD presenting as acute intestinal obstruction. A 26-year-old male patient presented to our emergency department with 3 days history of abdominal pain, ...

  2. Computation of the lateral and axial point spread functions in ...

    Indian Academy of Sciences (India)

    scanning microscopes for the above-mentioned amplitude filters. These results of axial and lateral irradiances are graphically represented by constructing a computer program using MATLAB. The obtained results are compared with that obtained in case of circular, annular, and Martinez-Corral apodized aperture. Keywords ...

  3. Fatigue Limit of Axially Compressed Concrete | Levchich | Nigerian ...

    African Journals Online (AJOL)

    An attempt to evaluate analytically the fatigue limit of axially loaded concrete depending upon the load parameters, number of load cycles and static short-term strength is presented. The conventional limit of concrete microcracking statical sustained strength of concrete, curvelinear relationship between fatigue limit and load ...

  4. Severe vertical atlanto-axial subluxation in rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Sílvia Fernandes

    2015-01-01

    Full Text Available The authors present the imaging study of a case of severe vertical atlanto-axial subluxation in a 60-year-old male with long-term rheumatoid arthritis with severe polyarticular involvement (Class IV of Steinbrocker functional classification.

  5. Report on the Dynamical Evolution of an Axially Symmetric Quasar ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The role of the angular momentum in the regular or chaotic character of motion in an axially symmetric quasar model is examined. It is found that, for a given value of the critical angular momentum , there are two values of the mass of the nucleus for which transition from regular to chaotic motion ...

  6. Report on the Dynamical Evolution of an Axially Symmetric Quasar ...

    Indian Academy of Sciences (India)

    Abstract. The role of the angular momentum in the regular or chaotic character of motion in an axially symmetric quasar model is examined. It is found that, for a given value of the critical angular momentum Lzc, there are two values of the mass of the nucleus Mn for which transition from regular to chaotic motion occurs.

  7. Axial-flow fan with eccentric rotor | Blaho | Zede Journal

    African Journals Online (AJOL)

    Axial-flow fan with eccentric rotor. M Blaho. Abstract. No Abstract. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for Journals ...

  8. Thorax deformity, joint hypermobility and anxiety disorder

    International Nuclear Information System (INIS)

    Gulsun, M.; Dumlu, K.; Erbas, M.; Yilmaz, Mehmet B.; Pinar, M.; Tonbul, M.; Celik, C.; Ozdemir, B.

    2007-01-01

    Objective was to evaluate the association between thorax deformities, panic disorder and joint hypermobility. The study includes 52 males diagnosed with thorax deformity, and 40 healthy male controls without thorax deformity, in Tatvan Bitlis and Isparta, Turkey. The study was carried out from 2004 to 2006. The teleradiographic and thoracic lateral images of the subjects were evaluated to obtain the Beighton scores; subjects psychiatric conditions were evaluated using the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-1), and the Hamilton Anxiety Scale (HAM-A) was applied in order to determine the anxiety levels. Both the subjects and controls were compared in sociodemographic, anxiety levels and joint mobility levels. In addition, males with joint hypermobility and thorax deformity were compared to the group with thorax deformity without joint hypermobility. A significant difference in HAM-A scores was found between the groups with thorax deformity and without. In addition, 21 subjects with thorax deformity met the joint hypermobility criteria in the group with thorax deformity and 7 subjects without thorax deformity met the joint hypermobility criteria in the group without thorax deformity, according to Beighton scoring. The Beighton score of subjects with thorax deformity were significantly different from those of the group without deformity. Additionally, anxiety scores of the males with thorax deformity and joint hypermobility were found higher than males with thorax deformity without joint hypermobility. Anxiety disorders, particularly panic disorder, have a significantly higher distribution in males subjects with thorax deformity compared to the healthy control group. In addition, the anxiety level of males with thorax deformity and joint hypermobility is higher than males with thorax deformity without joint hypermobility. (author)

  9. Deformation-Induced Phase Transitions in iPP Polymorphs

    Directory of Open Access Journals (Sweden)

    Harm J. M. Caelers

    2017-10-01

    Full Text Available This detailed study reveals the relation between structural evolution and the mechanical response of α -, β - and γ -iPP. Uni-axial compression experiments, combined with in situ WAXD measurements, allowed for the identification of the evolution phenomena in terms of phase composition. Tensile experiments in combination with SAXS revealed orientation and voiding phenomena, as well as structural evolution in the thickness of the lamellae and amorphous layers. On the level of the crystallographic unit cell, the WAXD experiments provided insight into the early stages of deformation. Moreover, transitions in the crystal phases taking place in the larger deformation range and the orientation of crystal planes were monitored. At all stretching temperatures, the crystallinity decreases upon deformation, and depending on the temperature, different new structures are formed. Stretching at low temperatures leads to crystal destruction and the formation of the oriented mesophase, independent of the initial polymorph. At high temperatures, above T α c , all polymorphs transform into oriented α -iPP. Small quantities of the initial structures remain present in the material. The compression experiments, where localization phenomena are excluded, show that these transformations take place at similar strains for all polymorphs. For the post yield response, the strain hardening modulus is decisive for the mechanical behavior, as well as for the orientation of lamellae and the evolution of void fraction and dimensions. β -iPP shows by far the most intense voiding in the entire experimental temperature range. The macroscopic localization behavior and strain at which the transition from disk-like void shapes, oriented with the normal in tensile direction, into fibrillar structures takes place is directly correlated with the strain hardening modulus.

  10. The Nucleon Axial Form Factor and Staggered Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Aaron Scott [Chicago U.

    2017-01-01

    The study of neutrino oscillation physics is a major research goal of the worldwide particle physics program over the upcoming decade. Many new experiments are being built to study the properties of neutrinos and to answer questions about the phenomenon of neutrino oscillation. These experiments need precise theoretical cross sections in order to access fundamental neutrino properties. Neutrino oscillation experiments often use large atomic nuclei as scattering targets, which are challenging for theorists to model. Nuclear models rely on free-nucleon amplitudes as inputs. These amplitudes are constrained by scattering experiments with large nuclear targets that rely on the very same nuclear models. The work in this dissertation is the rst step of a new initiative to isolate and compute elementary amplitudes with theoretical calculations to support the neutrino oscillation experimental program. Here, the eort focuses on computing the axial form factor, which is the largest contributor of systematic error in the primary signal measurement process for neutrino oscillation studies, quasielastic scattering. Two approaches are taken. First, neutrino scattering data on a deuterium target are reanalyzed with a model-independent parametrization of the axial form factor to quantify the present uncertainty in the free-nucleon amplitudes. The uncertainties on the free-nucleon cross section are found to be underestimated by about an order of magnitude compared to the ubiquitous dipole model parametrization. The second approach uses lattice QCD to perform a rst-principles computation of the nucleon axial form factor. The Highly Improved Staggered Quark (HISQ) action is employed for both valence and sea quarks. The results presented in this dissertation are computed at physical pion mass for one lattice spacing. This work presents a computation of the axial form factor at zero momentum transfer, and forms the basis for a computation of the axial form factor momentum dependence

  11. Axial SPN and radial MOC coupled whole core transport calculation

    International Nuclear Information System (INIS)

    Cho, Jin-Young; Kim, Kang-Seog; Lee, Chung-Chan; Zee, Sung-Quun; Joo, Han-Gyu

    2007-01-01

    The Simplified P N (SP N ) method is applied to the axial solution of the two-dimensional (2-D) method of characteristics (MOC) solution based whole core transport calculation. A sub-plane scheme and the nodal expansion method (NEM) are employed for the solution of the one-dimensional (1-D) SP N equations involving a radial transverse leakage. The SP N solver replaces the axial diffusion solver of the DeCART direct whole core transport code to provide more accurate, transport theory based axial solutions. In the sub-plane scheme, the radial equivalent homogenization parameters generated by the local MOC for a thick plane are assigned to the multiple finer planes in the subsequent global three-dimensional (3-D) coarse mesh finite difference (CMFD) calculation in which the NEM is employed for the axial solution. The sub-plane scheme induces a much less nodal error while having little impact on the axial leakage representation of the radial MOC calculation. The performance of the sub-plane scheme and SP N nodal transport solver is examined by solving a set of demonstrative problems and the C5G7MOX 3-D extension benchmark problems. It is shown in the demonstrative problems that the nodal error reaching upto 1,400 pcm in a rodded case is reduced to 10 pcm by introducing 10 sub-planes per MOC plane and the transport error is reduced from about 150 pcm to 10 pcm by using SP 3 . Also it is observed, in the C5G7MOX rodded configuration B problem, that the eigenvalues and pin power errors of 180 pcm and 2.2% of the 10 sub-planes diffusion case are reduced to 40 pcm and 1.4%, respectively, for SP 3 with only about a 15% increase in the computing time. It is shown that the SP 5 case gives very similar results to the SP 3 case. (author)

  12. Highly deformable bones: unusual deformation mechanisms of seahorse armor.

    Science.gov (United States)

    Porter, Michael M; Novitskaya, Ekaterina; Castro-Ceseña, Ana Bertha; Meyers, Marc A; McKittrick, Joanna

    2013-06-01

    Multifunctional materials and devices found in nature serve as inspiration for advanced synthetic materials, structures and robotics. Here, we elucidate the architecture and unusual deformation mechanisms of seahorse tails that provide prehension as well as protection against predators. The seahorse tail is composed of subdermal bony plates arranged in articulating ring-like segments that overlap for controlled ventral bending and twisting. The bony plates are highly deformable materials designed to slide past one another and buckle when compressed. This complex plate and segment motion, along with the unique hardness distribution and structural hierarchy of each plate, provide seahorses with joint flexibility while shielding them against impact and crushing. Mimicking seahorse armor may lead to novel bio-inspired technologies, such as flexible armor, fracture-resistant structures or prehensile robotics. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  13. CubeSat Deformable Mirror Demonstration

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of the CubeSat Deformable Mirror Demonstration is to characterize the performance of a small deformable mirror over a year in low-Earth orbit. Small form...

  14. Prediction of deformity in spinal tuberculosis

    NARCIS (Netherlands)

    Jutte, Paul; Wuite, Sander; The, Bertram; van Altena, Richard; Veldhuizen, Albert

    Tuberculosis of the spine may cause kyphosis, which may in turn cause late paraplegia, respiratory compromise, and unsightly deformity. Surgical correction therefore may be considered for large or progressive deformities. We retrospectively analyzed clinical and radiographic parameters to predict

  15. A Novel Anisotropic Hydrogel with Integrated Self-Deformation and Controllable Shape Memory Effect.

    Science.gov (United States)

    Le, Xiao-Xia; Zhang, Yu-Chong; Lu, Wei; Wang, Li; Zheng, Jing; Ali, Israt; Zhang, Jia-Wei; Huang, You-Ju; Serpe, Michael J; Yang, Xi-Tao; Fan, Xin-Dong; Chen, Tao

    2018-03-13

    Although shape memory polymers have been highlighted widely and developed rapidly, it is still a challenging task to realize complex temporary shapes automatically in practical applications. Herein, a novel shape memory hydrogel with the ability of self-deformation is presented. Through constructing an anisotropic poly(acrylic acid)-polyacrylamide (PAAc-PAAm) structure, the obtained hydrogel exhibits stable self-deformation behavior in response to pH stimulus, and the shapes that formed automatically can be fixed by the coordination between carboxylic groups and Fe 3+ ; therefore, self-deformation and shape memory behaviors are integrated in one system. Moreover, the magnitude of auto-deformation and shape memory could be adjusted with the concentration of corresponding ions, leading to programmable shape memory and shape recovery processes. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Azimuthal velocity profiles in Rayleigh-stable Taylor–Couette flow and implied axial angular momentum transport

    NARCIS (Netherlands)

    Nordsiek, F.; Huisman, Sander Gerard; van der Veen, Roeland; Sun, Chao; Lohse, Detlef; Lathrop, D.P.

    2015-01-01

    We present azimuthal velocity profiles measured in a Taylor–Couette apparatus, which has been used as a model of stellar and planetary accretion disks. The apparatus has a cylinder radius ratio of ${\\it\\eta}=0.716$η=0.716, an aspect ratio of ${\\it\\Gamma}=11.74$Γ=11.74, and the plates closing the

  17. Non-steroidal anti-inflammatory drugs (NSAIDs) for axial spondyloarthritis (ankylosing spondylitis and non-radiographic axial spondyloarthritis)

    NARCIS (Netherlands)

    Kroon, Feline P. B.; van der Burg, Lennart R. A.; Ramiro, Sofia; Landewé, Robert B. M.; Buchbinder, Rachelle; Falzon, Louise; van der Heijde, Désirée

    2015-01-01

    Axial spondyloarthritis (axSpA) comprises ankylosing spondylitis (radiographic axSpA) and non-radiographic (nr-)axSpA and is associated with psoriasis, uveitis and inflammatory bowel disease. Non-steroidal anti-inflammatory drugs (NSAIDs) are recommended as first-line drug treatment. To determine

  18. Two-dimensional nonlinear dynamics of an axially moving viscoelastic beam with time-dependent axial speed

    International Nuclear Information System (INIS)

    Ghayesh, Mergen H.; Amabili, Marco; Farokhi, Hamed

    2013-01-01

    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)

  19. Quantum dynamics of deformed open systems

    CERN Document Server

    Isar, A

    2002-01-01

    A master equation for the deformed quantum harmonic oscillator interacting with a dissipative environment, in particular with a thermal bath, is derived in the microscopic model using perturbation theory . The coefficient of the master equation depend on the deformation function. The steady state solution of the equation for the density matrix in the number representation is obtained and the equilibrium energy of the deformed harmonic oscillator is calculated in the approximation of small deformation. (author)

  20. Theoretical investigations on two-phase flow instability in parallel channels under axial non-uniform heating

    International Nuclear Information System (INIS)

    Lu, Xiaodong; Wu, Yingwei; Zhou, Linglan; Tian, Wenxi; Su, Guanghui; Qiu, Suizheng; Zhang, Hong

    2014-01-01

    Highlights: • We developed a model based on homogeneous flow model to analyze two-phase flow instability in parallel channels. • The influence of axial non-uniform heating on the system stability has been investigated. • Influences of various factors on system instability under cosine heat flux have been studied. • The system under top-peaked heat flux is the most stable system. - Abstract: Two-phase flow instability in parallel channels heated by axial non-uniform heat flux has been theoretically studied in this paper. The system control equations of parallel channels were established based on the homogeneous flow model in two-phase region. Semi-implicit finite-difference scheme and staggered mesh method were used to discretize the equations, and the difference equations were solved by chasing method. Cosine, bottom-peaked and top-peaked heat fluxes were used to study the influence of non-uniform heating on two-phase flow instability of the parallel channels system. The marginal stability boundaries (MSB) of parallel channels and three-dimensional instability spaces (or instability reefs) under different heat flux conditions have been obtained. Compared with axial uniform heating, axial non-uniform heating will affect the system stability. Cosine and bottom-peaked heat fluxes can destabilize the system stability in high inlet subcooling region, while the opposite effect can be found in low inlet subcooling region. However, top-peaked heat flux can enhance the system stability in the whole region. In addition, for cosine heat flux, increasing the system pressure or inlet resistance coefficient can strengthen the system stability, and increasing the heating power will destabilize the system stability. The influence of inlet subcooling number on the system stability is multi-valued under cosine heat flux

  1. Alloy synthesis using the mach stem region in an axial symmetric implosive shock: Understanding the pressure strain-temperature contributions

    Energy Technology Data Exchange (ETDEWEB)

    Staudhammer, Karl P.

    2004-01-01

    The Mach stem region in an axial symmetric shock implosion has generally been avoided in the dynamic consolidation of powders for a number of reasons. The prime reason being that the convergence of the shock waves in the cylindrical axis produce enormous pressures and concomitant temperatures that have melted tungsten. This shock wave convergence consequently results in a discontinuity in the hydro-code calculations. Dynamic deformation experiments on gold plated 304L stainless steel powders were undertaken. These experiments utilized pressures of 0.08 to 1.0 Mbar and contained a symmetric radial melt region along the central axis of the sample holder. To understand the role of deformation in a porous material, the pressure, and temperature as well as the deformation heat and associated defects must be accounted for. When the added heat of consolidation deformation exceeds the melt temperature of the 304 powders, a melt zone results that can consume large regions of the compact while still under the high-pressure pulse. As the shock wave traverses the sample and is removed in a momentum trap, its pressure/temperature are quenched. It is within this region that very high diffusion/alloying occurs and has been observed in the gold plated powders. Anomalous increases of gold diffusion into 304 stainless steel have been observed via optical microscopy, scanning electron microscopy and EDAX measurements. Values exceeding 1200 m/sec have been measured and correlated to the powder sizes, size distribution and packing density, concomitant with sample container strains ranging from 2.0% to 26%.

  2. Three-dimensional analysis of tarsal bone response to axial loading in patients with hallux valgus and normal feet.

    Science.gov (United States)

    Watanabe, Kota; Ikeda, Yasutoshi; Suzuki, Daisuke; Teramoto, Atsushi; Kobayashi, Takuma; Suzuki, Tomoyuki; Yamashita, Toshihiko

    2017-02-01

    Patients with hallux valgus present a variety of symptoms that may be related to the type of deformity. Weightbearing affects the deformities, and the evaluation of the load response of tarsal bones has been mainly performed using two-dimensional plane radiography. The purpose of this study was to investigate and compare structural changes in the medial foot arch between patients with hallux valgus and normal controls using a computer image analysis technique and weightbearing computed tomography data. Eleven patients with hallux valgus and eleven normal controls were included. Computed tomograms were obtained with and without simulated weightbearing using a compression device. Computed tomography data were transferred into a personal computer, and a three-dimensional bone model was created using image analysis software. The load responses of each tarsal bone in the medial foot arch were measured three-dimensionally and statistically compared between the two groups. Displacement of each tarsal bone under two weightbearing conditions was visually observed by creating three-dimensional bone models. At the first metatarsophalangeal joint, the proximal phalanges of the hallux valgus group showed significantly different displacements in multiple directions. Moreover, opposite responses to axial loading were also observed in both translation and rotation between the two groups. Weightbearing caused deterioration of the hallux valgus deformity three-dimensionally at the first metatarsophalangeal joint. Information from the computer image analysis was useful for understanding details of the pathology of foot disorders related to the deformities or instability and may contribute to the development of effective conservative and surgical treatments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Pathological Bones Fragility: Drug Treatment of Bone Tissue and Surgical Correction of Bones Deformation

    Directory of Open Access Journals (Sweden)

    Yu. M. Guk

    2012-04-01

    Full Text Available The paper presents a current approach to treatment of patients with orthopaedic pathology associated with imperfect osteogenesis as well as a promising trend of drug therapy of bone tissue and surgical treatment of pathological fractures and axial deformation of long bones. The authors analyzed the results of treatment of 22 patients with imperfect osteogenesis using a new method consisted of pathogenetic antiosteoporosis therapy and «growing» telescope-type intramedullary constructions. The effectiveness and potential of the mentioned method for treatment and prevention have been determined and approved through objective evidence.

  4. Shell effects in the nuclear deformation energy

    International Nuclear Information System (INIS)

    Ross, C.K.

    1973-01-01

    A new approach to shell effects in the Strutinsky method for calculating nuclear deformation energy is evaluated and the suggestion of non-conservation of angular momentum in the same method is resolved. Shell effects on the deformation energy in rotational bands of deformed nuclei are discussed. (B.F.G.)

  5. Deformed configurations, band structures and spectroscopic ...

    Indian Academy of Sciences (India)

    2014-03-20

    Mar 20, 2014 ... Here, we study theoretically the low-lying as well as the excited deformed bands and their electromagnetic properties to search for various structures, spherical and deformed, of the exotic nuclei 82Ge and 84Se by employing the deformed Hartree–Fock (HF) and angular momentum (J) projection method ...

  6. Conformal deformation of Riemann space and torsion

    International Nuclear Information System (INIS)

    Pyzh, V.M.

    1981-01-01

    Method for investigating conformal deformations of Riemann spaces using torsion tensor, which permits to reduce the second ' order equations for Killing vectors to the system of the first order equations, is presented. The method is illustrated using conformal deformations of dimer sphere as an example. A possibility of its use when studying more complex deformations is discussed [ru

  7. Phase space deformations in phantom cosmology

    Science.gov (United States)

    López, J. L.; Sabido, M.; Yee-Romero, C.

    2018-03-01

    We discuss the physical consequences of general phase space deformations on the minisuperspace of phantom cosmology. Based on the principle of physically equivalent descriptions in the deformed theory, we investigate for what values of the deformation parameters the arising descriptions are physically equivalent. We also construct and solve the quantum model and derive the semiclassical dynamics.

  8. A Bloch-Torrey Equation for Diffusion in a Deforming Media

    International Nuclear Information System (INIS)

    Rohmer, Damien; Gullberg, Grant T.

    2006-01-01

    Diffusion Tensor Magnetic Resonance Imaging (DTMRI)technique enables the measurement of diffusion parameters and therefore, informs on the structure of the biological tissue. This technique is applied with success to the static organs such as brain. However, the diffusion measurement on the dynamically deformable organs such as the in-vivo heart is a complex problem that has however a great potential in the measurement of cardiac health. In order to understand the behavior of the Magnetic Resonance (MR)signal in a deforming media, the Bloch-Torrey equation that leads the MR behavior is expressed in general curvilinear coordinates. These coordinates enable to follow the heart geometry and deformations through time. The equation is finally discredited and presented in a numerical formulation using implicit methods, in order to get a stable scheme that can be applied to any smooth deformations. Diffusion process enables the link between the macroscopic behavior of molecules and the microscopic structure in which they evolve. The measurement of diffusion in biological tissues is therefore of major importance in understanding the complex underlying structure that cannot be studied directly. The Diffusion Tensor Magnetic Resonance Imaging(DTMRI) technique enables the measurement of diffusion parameters and therefore provides information on the structure of the biological tissue. This technique has been applied with success to static organs such as the brain. However, diffusion measurement of dynamically deformable organs such as the in-vivo heart remains a complex problem, which holds great potential in determining cardiac health. In order to understand the behavior of the magnetic resonance (MR) signal in a deforming media, the Bloch-Torrey equation that defines the MR behavior is expressed in general curvilinear coordinates. These coordinates enable us to follow the heart geometry and deformations through time. The equation is finally discredited and presented in a

  9. 1980 Volvo award in biomechanics. Measurement of the distribution of axial stress on the end-plate of the vertebral body.

    Science.gov (United States)

    Horst, M; Brinckmann, P

    1981-01-01

    The distribution of axial stress on the end-plate of the vertebral body has been measured by the aid of miniature piezoelectric pressure transducers in specimens of motion segments of the human vertebral column. The results indicate that the stress distribution depends essentially on the state of degeneration of the intervertebral disc and on the relative position of the adjacent end-plates. Furthermore lumbar and thoracic motion segments show a different behaviour. The measured results relate to the problem of the stress dependent deformation of the growing vertebra, the codfish shape of the osteoporotic vertebra and to the mechanism of degeneration of the intervertebral disc.

  10. Stable corrugated state of the two-dimensional electron gas

    International Nuclear Information System (INIS)

    Mendez-Moreno, R.M.; Moreno, M.; Ortiz, M.A.

    1991-01-01

    A corrugated and stable ground state is found for the two-dimensional electron gas in both the normal paramagnetic and the fully polarized phases. The self-consistent Hartree-Fock method is used with a modulated set of trial wave functions within the deformable jellium model. The results for high metallic densities reproduce the usual noncorrugated ferromagnetic electron-gas behavior. A transition to a paramagnetic corrugated state for values of r s ∼6.5 is predicted. At lower densities r s ∼30, a second transition to a corrugated ferromagnetic phase is suggested

  11. Nucleon deformation. A status report

    International Nuclear Information System (INIS)

    Papanicolas, C.N.

    2003-01-01

    The conjectured deformation of hadrons and its experimental verification offer a particularly fertile ground for understanding the intricate dynamics of their constituents and QCD at the confinement scale. The detailed study of the N→Δ transition is viewed as the preferred method of experimental investigation of this central issue in hadronic physics. A brief overview of the field is presented, followed by a presentation of the most recent results from Bates N→Δ program. The new Bates/OOPS data at Q 2 =0.127 GeV/c 2 yield R SM =(-6.27±0.32 stat+sys ±0.10 model )% and R EM =(-2.00±0.40 stat+sys ±0.27 model )% and they exclude a spherical nucleon and/or Δ. The magnitude and the origin of the deformation is the focus of the ongoing and planned investigations. (orig.)

  12. A rotational and axial motion system load frame insert for in situ high energy x-ray studies

    Energy Technology Data Exchange (ETDEWEB)

    Shade, Paul A., E-mail: paul.shade.1@us.af.mil; Schuren, Jay C.; Turner, Todd J. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Blank, Basil [PulseRay, Beaver Dams, New York 14812 (United States); Kenesei, Peter; Goetze, Kurt; Lienert, Ulrich; Almer, Jonathan [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Suter, Robert M. [Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Bernier, Joel V.; Li, Shiu Fai [Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Lind, Jonathan [Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2015-09-15

    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.

  13. Hindfoot Arthrodesis for Neuropathic Deformity

    Directory of Open Access Journals (Sweden)

    Peng-Ju Huang

    2007-03-01

    Full Text Available Acquired neurologic disorders of the foot lead to arthrosis, deformities, instabilities, and functional disabilities. Hindfoot arthrodesis is the current option available for irreducible or nonbraceable deformities of neuropathic feet. However, the role of ankle arthrodesis in these patients has been questioned because of high nonunion and complication rates. From 1990 to 2001, 17 cases of acquired neuropathic foot deformities were treated by four tibiotalocalcaneal (TTC arthrodeses and 13 ankle arthrodeses. TTC arthrodesis was performed on cases with combined ankle and subtalar arthritis or cases whose deformities or instabilities could not be corrected by ankle fusion alone. There was no nonunion of TTC arthrodesis and seven ununited ankle arthrodeses were salvaged by two TTC-attempted arthrodeses and five revision ankle-attempted arthrodeses. Eventually in these cases, there was one nonunion in TTC arthrodesis and one nonunion in revision ankle arthrodesis. The final fusion rate was 88% (15 of 17 cases with average union time of 6.9 months (range, 2.5–18 months. The American Orthopaedic Foot and Ankle Society ankle hind-foot functional scores were evaluated: one was excellent (5.8%, seven were good (41%, eight were fair (53.3%, and one was poor (5.8% in terms of total functional outcome. We conclude that TTC arthrodesis is indicated for cases with ankle and subtalar involvement and ankle arthrodesis is an alternative for cases with intact subtalar joint. We recommend revision ankle arthrodesis if the ankle fails to fuse and the bone stock of the talus is adequate. TTC arthrodesis is reserved for ankles with poor bone stock of the talus with fragmentation.

  14. Deterritorializing Drawing - transformation/deformation

    DEFF Research Database (Denmark)

    Brabrand, Helle

    2012-01-01

    but also from within by sensations, body ‘images’ are different to all other images. Twisting these body images make a mode of operation of art. The paper will address the above issues discussing modes of operation and appearance of my actual project. Acting in the reality of drawing, the project confront...... the body, situated in real time and depth, with drawing transforming and deforming time and depth....

  15. Axial Compression Tests on Corroded Reinforced Concrete Columns Consolidated with Fibre Reinforced Polymers

    Directory of Open Access Journals (Sweden)

    Bin Ding

    2017-06-01

    Full Text Available Reinforced concrete structure featured by strong bearing capacity, high rigidity, good integrity, good fire resistance, and extensive applicability occupies a mainstream position in contemporary architecture. However, with the development of social economy, people need higher requirements on architectural structure; durability, especially, has been extensively researched. Because of the higher requirement on building material, ordinary reinforced concrete structure has not been able to satisfy the demand. As a result, some new materials and structures have emerged, for example, fibre reinforced polymers. Compared to steel reinforcement, fibre reinforced polymers have many advantages, such as high tensile strength, good durability, good shock absorption, low weight, and simple construction. The application of fibre reinforced polymers in architectural structure can effectively improve the durability of the concrete structure and lower the maintenance, reinforcement, and construction costs in severe environments. Based on the concepts of steel tube concrete, fibre reinforced composite material confined concrete, and fibre reinforced composite material tubed concrete, this study proposes a novel composite structure, i.e., fibre reinforced composite material and steel tube concrete composite structure. The structure was developed by pasting fibre around steel tube concrete and restraining core concrete using fibre reinforced composite material and steel tubes. The bearing capacity and ultimate deformation capacity of the structure was tested using column axial compression test.

  16. Performance Analysis of CFRP Composite Strips Confined RC Columns under Axial Compression

    Directory of Open Access Journals (Sweden)

    J. Raja Murugadoss

    2015-01-01

    Full Text Available In an attempt to mitigate the high cost of FRP composite strengthening, an experimental investigation was carried out that sought to achieve efficient and most favorable FRP strengthening using CFRP composite strips. 50 mm wide CFRP composite strips were used in two different spacings (20 mm and 40 mm to confine columns. The test results of the column confined with smaller spacing (20 mm showed significant restraint of axial deformation of the column and enhanced the strength capacity to a maximum of 99.20% compared to that of reference column. In contrast, the column confined by strips with larger spacing (40 mm failed by crushing of concrete alone, which occurred even before the CFRP strips reached their ultimate strain. In addition, the embodied energy that exists in the CFRP strips could not be utilized effectively. The stress and strength enhancement ratio of this present study was compared with the previous research that has been conducted on columns confined with full wrapping. From the obtained results, it is recommended that CFRP strips with a spacing of 20 mm be used to improve the strength capacity of the RC column; in addition, this wrapping technique provides economic benefits compared to a column confined with full wrapping.

  17. Fatigue Assessment of Nickel-Titanium Peripheral Stents: Comparison of Multi-Axial Fatigue Models

    Science.gov (United States)

    Allegretti, Dario; Berti, Francesca; Migliavacca, Francesco; Pennati, Giancarlo; Petrini, Lorenza

    2018-02-01

    Peripheral Nickel-Titanium (NiTi) stents exploit super-elasticity to treat femoropopliteal artery atherosclerosis. The stent is subject to cyclic loads, which may lead to fatigue fracture and treatment failure. The complexity of the loading conditions and device geometry, coupled with the nonlinear material behavior, may induce multi-axial and non-proportional deformation. Finite element analysis can assess the fatigue risk, by comparing the device state of stress with the material fatigue limit. The most suitable fatigue model is not fully understood for NiTi devices, due to its complex thermo-mechanical behavior. This paper assesses the fatigue behavior of NiTi stents through computational models and experimental validation. Four different strain-based models are considered: the von Mises criterion and three critical plane models (Fatemi-Socie, Brown-Miller, and Smith-Watson-Topper models). Two stents, made of the same material with different cell geometries are manufactured, and their fatigue behavior is experimentally characterized. The comparison between experimental and numerical results highlights an overestimation of the failure risk by the von Mises criterion. On the contrary, the selected critical plane models, even if based on different damage mechanisms, give a better fatigue life estimation. Further investigations on crack propagation mechanisms of NiTi stents are required to properly select the most reliable fatigue model.

  18. Deformation of PWR cladding following a loss-of-coolant accident

    International Nuclear Information System (INIS)

    Hindle, E.D.; Mann, C.A.

    1979-07-01

    A review is presented of recent experiments to investigate the deformation behaviour of Zircaloy cladding in simulated loss-of-coolant accidents. The behaviour of Zircaloy cladding is shown to be controlled by a complex interaction of metallurgical and heat transfer variables, with the latter having a major influence. There is a significant increase in both diametral strain and the axial extent of deformation in multi-rod compared with single-rod tests. The extent to which this will occur in nuclear-heated tests is not yet known; however, it is expected that the 'smearing' of the gamma-radiation portion of decay heat in such tests will tend to reduce circumferential temperature variations. Opposing this is the influence of the colder control rods in an assembly. The resolution of this dichotomy will require a series of in-reactor multi-rod tests and attendant code development. (author)

  19. MABEL-1. A code to analyse cladding deformation in a loss-of-coolant accident

    International Nuclear Information System (INIS)

    Bowring, R.W.; Cooper, C.A.

    1978-06-01

    The MABEL-1 code has been written to investigate the deformation, of fuel pin cladding and its effects on fuel pin temperature transients during a loss-of-coolant accident. The code considers a single fuel pin with heated fuel concentric within the cladding. The fuel pin temperature distribution is evaluated using a one-dimensional conduction model with heat transfer to the coolant represented by an input set of heat transfer coefficients. The cladding deformation is calculated using the code CANSWEL, which assumes all strain to be elastic or creep and models the creep under a multi-axial stress system by a spring/dashpot combination undergoing alternate relaxation and elastic strain. (author)

  20. Large elastic-plastic deformations of slender beams: Co-rotational theory vs. von Karman theory

    Science.gov (United States)

    Jiang, J.; Olson, M. D.

    1994-11-01

    The consistent co-rotational beam formulation has been modified to include inelastic deformation using a sublayer material model. An explicit tangent stiffness matrix for a non-conservative beam was consistently derived from the assumed beam kinematics. Several example problems were solved to verify the formulation and, subsequently, a comparative study was carried out to examine the validity of the von Karman theory in large deflection analysis. It is found that the presence of beam axial constraint plays an important role on the performance of the von Karman approximation. In general, the von Karman formulation can provide reasonable solutions to large deformation problems of extensional structures, but its performance becomes unsatisfactory for the inextensional case even under relatively small deflections.