WorldWideScience

Sample records for vibrated metallic circular

  1. Forced vibrations of rotating circular cylindrical shells

    International Nuclear Information System (INIS)

    Igawa, Hirotaka; Maruyama, Yoshiyuki; Endo, Mitsuru

    1995-01-01

    Forced vibrations of rotating circular cylindrical shells are investigated. Basic equations, including the effect of initial stress due to rotation, are formulated by the finite-element method. The characteristic relations for finite elements are derived from the energy principle by considering the finite strain. The equations of motion can be separated into quasi-static and dynamic ones, i.e., the equations in the steady rotating state and those in the vibration state. Radial concentrated impulses are considered as the external dynamic force. The transient responses of circular cylindrical shells are numerically calculated under various boundary conditions and rotating speeds. (author)

  2. Vibration of circular bladed disk with imperfections

    Czech Academy of Sciences Publication Activity Database

    Půst, Ladislav; Pešek, Luděk

    2011-01-01

    Roč. 21, č. 10 (2011), s. 2893-2904 ISSN 0218-1274 R&D Projects: GA ČR GA101/09/1166 Institutional research plan: CEZ:AV0Z20760514 Keywords : circular bladed disk * vibration * imperfection * nonlinear damping Subject RIV: BI - Acoustics Impact factor: 0.755, year: 2011 http://www.worldscinet.com/ijbc/21/2110/S0218127411030210.html

  3. Optimization design of high power ultrasonic circular ring radiator in coupled vibration.

    Science.gov (United States)

    Xu, Long; Lin, Shuyu; Hu, Wenxu

    2011-10-01

    This paper presents a new high power ultrasonic (HPU) radiator, which consists of a transducer, an ultrasonic horn, and a metal circular ring. Both the transducer and horn in longitudinal vibrations are used to drive a metal circular ring in a radial-axial coupled vibration. This coupled vibration cannot only generate ultrasound in both the radial and axial directions, but also focus the ultrasound inside the circular ring. Except for the radial-axial coupled vibration mode, the third longitudinal harmonic vibration mode with relative large vibration amplitude is also detected, which can be used as another operation mode. Overall, the HPU with these two vibration modes should have good potential to be applied in liquid processing, such as sonochemistry, ultrasonic cleaning, and Chinese herbal medicine extraction. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Flow-induced vibration of circular cylindrical structures

    International Nuclear Information System (INIS)

    Chen, S.S.

    1985-06-01

    This report summarizes the flow-induced vibration of circular cylinders in quiescent fluid, axial flow, and crossflow, and applications of the analytical methods and experimental data in design evaluation of various system components consisting of circular cylinders. 219 figs., 30 tabs

  5. Direct access to polyisocyanide screw sense using vibrational circular dichroism

    NARCIS (Netherlands)

    Schwartz, E.; Domingos, S.R.; Vdovin, A.; Koepf, M.; Buma, W.J.; Cornelissen, J.J.L.M.; Rowan, A.E.; Nolte, R.J.M.; Woutersen, S.

    2010-01-01

    We show that the screw sense of polyisocyanide helices can be determined in a simple manner from the vibrational circular dichroism (VCD) of their CN-stretching mode. The relation between VCD and molecular structure is obtained using the coupled-oscillator approximation. It is shown that since the

  6. Flow-induced vibrations of circular cylindrical structures

    International Nuclear Information System (INIS)

    Chen, S.

    1977-06-01

    The problems of flow-induced vibrations of circular cylindrical structures are reviewed. First, the general method of analysis and classification of structural responses are presented. Then, the presentation is broken up along the lines with stationary fluid, parallel flow, and cross flow. Finally, design considerations and future research needs are pointed out. 234 references

  7. Analysis of radial vibrations of poroelastic circular cylindrical shells ...

    African Journals Online (AJOL)

    DR OKE

    vanished, the considered problem reduces to the problem of radial vibrations of fluid-filled poroelastic circular cylindrical shell. (2). When the .... the volume change of the solid to that of liquid. ..... When the outer fluid density is zero, that is, ρof = 0 then the poroelastic cylindrical shell immersed in an acoustic medium will.

  8. Flow-Induced Vibration of Circular Cylindrical Structures

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shoei-Sheng [Argonne National Lab. (ANL), Argonne, IL (United States). Components Technology Division

    1985-06-01

    Flow-induced vibration is a term to denote those phenomena associated with the response of structures placed in or conveying fluid flow. More specifically, the terra covers those cases in which an interaction develops between fluid-dynamic forces and the inertia, damping or elastic forces in the structures. The study of these phenomena draws on three disciplines: (1) structural mechanics, (2) mechanical vibration, and (3) fluid dynamics. The vibration of circular cylinders subject to flow has been known to man since ancient times; the vibration of a wire at its natural frequency in response to vortex shedding was known in ancient Greece as aeolian tones. But systematic studies of the problem were not made until a century ago when Strouhal established the relationship between vortex shedding frequency and flow velocity for a given cylinder diameter. The early research in this area has beer summarized by Zdravkovich (1985) and Goldstein (1965). Flow-induced structural vibration has been experienced in numerous fields, including the aerospace industry, power generation/transmission (turbine blades, heat exchanger tubes, nuclear reactor components), civil engineering (bridges, building, smoke stacks), and undersea technology. The problems have usually been encountered or created accidentally through improper design. In most cases, a structural or mechanical component, designed to meet specific objectives, develops problems when the undesired effects of flow field have not been accounted for in the design. When a flow-induced vibration problem is noted in the design stage, the engineer has different options to eliminate the detrimental vibration. Unfortunately, in many situations, the problems occur after the components are already in operation; the "fix" usually is very costly. Flow-induced vibration comprises complex and diverse phenomena; subcritical vibration of nuclear fuel assemblies, galloping of transmission lines, flutter of pipes conveying fluid, and whirling

  9. Electronic and vibrational circular dichroism spectra of (R)-(-)-apomorphine

    Energy Technology Data Exchange (ETDEWEB)

    Abbate, Sergio, E-mail: abbate@med.unibs.it [Dipartimento di Scienze Biomediche e Biotecnologie, Universita di Brescia, Viale Europa 11, 25123 Brescia (Italy); CNISM, Consorzio Interuniversitario Scienze Fisiche della Materia, Via della Vasca Navale 84, 00146 Roma (Italy); Longhi, Giovanna; Lebon, France [Dipartimento di Scienze Biomediche e Biotecnologie, Universita di Brescia, Viale Europa 11, 25123 Brescia (Italy); CNISM, Consorzio Interuniversitario Scienze Fisiche della Materia, Via della Vasca Navale 84, 00146 Roma (Italy); Tommasini, Matteo [Dipartimento di Chimica, Materiali e Ingegneria Chimica ' G. Natta' , Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Consorzio Interuniversitario per la Scienza e Tecnologia dei Materiali (INSTM), Unita di Ricerca del Politecnico di Milano (Dip. CMIC), Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2012-09-11

    Highlights: Black-Right-Pointing-Pointer ECD and VCD Spectra of (R)-(-)-apomorphine measured in various solvents. Black-Right-Pointing-Pointer DFT calculations allow to study the protonation state and conformations. Black-Right-Pointing-Pointer Contributions from catechol OH vibrations to the VCD spectra is studied. -- Abstract: Apomorphine is a chiral drug molecule; notwithstanding its extraordinary importance, little attention has been paid to the characterization of its chiroptical properties. Here we report on its electronic circular dichroism (ECD) spectra, recorded in methanol and water, and vibrational circular dichroism (VCD) in methanol and dimethyl sulfoxide (DMSO) solutions. Density functional theory (DFT) calculations have allowed us to interpret the spectra and to evaluate the role of possible conformations, charge-states and interactions with counter ions.

  10. Research on Radial Vibration of a Circular Plate

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2016-01-01

    Full Text Available Radial vibration of the circular plate is presented using wave propagation approach and classical method containing Bessel solution and Hankel solution for calculating the natural frequency theoretically. In cylindrical coordinate system, in order to obtain natural frequency, propagation and reflection matrices are deduced at the boundaries of free-free, fixed-fixed, and fixed-free using wave propagation approach. Furthermore, radial phononic crystal is constructed by connecting two materials periodically for the analysis of band phenomenon. Also, Finite Element Simulation (FEM is adopted to verify the theoretical results. Finally, the radial and piezoelectric effects on the band are also discussed.

  11. Vibrational entropies in metallic alloys

    Science.gov (United States)

    Ozolins, Vidvuds; Asta, Mark; Wolverton, Christopher

    2000-03-01

    Recently, it has been recognized that vibrational entropy can have significant effects on the phase stability of metallic alloys. Using density functional linear response calculations and molecular dynamics simulations we study three representative cases: (i) phase diagram of Al-rich Al-Sc alloys, (ii) stability of precipitate phases in CuAl_2, and (iii) phonon dynamics in bcc Zr. We find large vibrational entropy effects in all cases. In the Al-Sc system, vibrations increase the solid solubility of Sc in Al by decreasing the stability of the L12 (Al_3Sc) phase. This leads to a nearly ten-fold increase in the solid solubility of Sc in Al at T=800 K. In the Cu-Al system, our calculations predict that the tetragonal Laves phase of CuAl2 has 0.35 kB/atom higher vibrational entropy than the cubic CaF_2-type phase (the latter is predicted to be the T=0 K ground state of CuAl_2). This entropy difference causes a structural transformation in CuAl2 precipitates from the fluorite to the tetragonal Laves phase around T=500 K. Finally, we analyze the highly unusual dynamics of anharmonically stabilized bcc Zr, finding large diffuse-scattering intensity streaks between the bcc Bragg peaks.

  12. Vibrations of composite circular shell structures due to transient loads

    International Nuclear Information System (INIS)

    Schrader, K.-H.; Krutzik, N.; Winkel, G.

    1975-01-01

    Referring to a container consisting of different shell structures - such as spherical, cylindrical and conical shells - the dynamic behavior of coupled spatial shell structures due to transient loads will be investigated. The spatial structure including the filling of water will be idealized as a three-dimensional model consisting of ring elements. The influence of the water filling on the vibrations will be considered by virtual masses added to the shell structures. In circular direction as well as in meridional direction a consistent mass model has been used. By variation of the virtual masses it will be clarified, how these additional masses influence the vibrational behavior of the composed system. Another aspect which will be investigated is the influence of different stiffnesses of substructures or parts of substructures on the natural frequencies, and on their affiliated eigensystems. Furthermore, the maximum and minimum stresses in the structures caused by transient loads acting on the inner surface of the shells will be explored. Here it seems to be possible to locate an area of maximum strain. Rotational loads as well as nonrotational loads will be considered

  13. Modeling and analysis of circular flexural-vibration-mode piezoelectric transformer.

    Science.gov (United States)

    Huang, Yihua; Huang, Wei

    2010-12-01

    We propose a circular flexural-vibration-mode piezoelectric transformer and perform a theoretical analysis of the transformer. An equivalent circuit is derived from the equations of piezoelectricity and the Hamilton's principle. With this equivalent circuit, the voltage gain ratio, input impedance, and the efficiency of the circular flexural-vibration-mode piezoelectric transformer can be determined. The basic behavior of the transformer is shown by numerical results.

  14. In-Plane Vibrations of Circular Curved Beams with a Transverse Open Crack

    OpenAIRE

    Öz, H. R.; Daş, M. T.

    2006-01-01

    In this study, the in plane vibrations of cracked circular curved beams is investigated. The beam is an Euler-Bernoulli beam. Only bending and extension effects are included. The curvature is in a single plane. In plane vibrations is analyzed using FEM. In the analysis, elongation, bending and rotary inertia effects are included. Four degrees of freedom for in-plane vibrations is assumed. Natural frequencies of the beam with a crack in different locations and depths are calculated using FEM. ...

  15. Vibration of a group of circular cylinders subjected to fluid flow

    International Nuclear Information System (INIS)

    Chen, S.

    1981-01-01

    Many structural and mechanical components consist of multiple circular cylinders, such as heat exchanger tubes and nuclear fuel bundles. These components are subjected to fluid flow. The fluid flow represents a source of energy that can induce and sustain vibration. The fluid moving with vibrating structures has an important effect on the dynamic characteristics of the structure. The objective of this paper is to review the dynamics of multiple circular cylinders in stationary fluid, parallel flow and cross flow, and to present general design guides to avoid detrimental vibration and instability. 77 refs

  16. Piezoelectric shunt damping of a circular saw blade with autonomous power supply for noise and vibration reduction

    Science.gov (United States)

    Pohl, Martin; Rose, Michael

    2016-01-01

    Circular saws are widespread tools for machining metal, wood or even ceramics. Due to the thin blade and excitation by the workpiece contact of the cutting edges, circular saws are prone to vibration and intense noise emission. Damping the blade will lower the hearing protection requirements of the users and possibly increase precision. Therefore a new damping concept for circular saw blades is presented in this paper. It is based on negative capacitance shunted piezoelectric transducers which are applied to the saw blade core. The required energy for the electronics is harvested from the rotation by a generator, so that no change of the machine tool is required. All components are integrated into an autonomous saw tool. Finally, the system is experimentally investigated without rotation, in idling and in cutting condition in a circular saw test stand in the Institute for Machine Tools and Production Engineering (IWF) at TU Braunschweig. The experimental investigation shows a good reduction of the vibration amplitude over a wide frequency range in the non-rotating condition. When rotating, the damping effect is lower and limited to some narrow frequency bands. The proposed reason for the reduced damping effect in rotating condition consists in the saturation of the electronic circuits due to the limited supply voltage capabilities.

  17. Three-dimensional free vibration analysis of thick laminated circular ...

    African Journals Online (AJOL)

    Dr Oke

    1 ,2 Department of Mechanical Engineering, Maulana Azad National Institute of Technology, Bhopal-462003, INDIA ... In this communication, a numerical analysis regarding free vibration of thick laminated .... ANSYS finite element software.

  18. Circularly polarized infrared and visible sum-frequency-generation spectroscopy: Vibrational optical activity measurement

    International Nuclear Information System (INIS)

    Cheon, Sangheon; Cho, Minhaeng

    2005-01-01

    Vibrational optical activity spectroscopies utilizing either circularly polarized ir or circularly polarized visible beams were theoretically investigated by considering the infrared and visible sum-frequency-generation (IV-SFG) schemes. In addition to the purely electric dipole-allowed chiral component of the IV-SFG susceptibility, the polarizability-electric quadrupole hyperpolarizability term also contributes to the vibrationally resonant IV-SFG susceptibility. The circular-intensity-difference signal is shown to be determined by the interferences between the all-electric dipole-allowed chiral component and the polarizability-electric-dipole or electric-dipole-electric-quadrupole Raman optical activity tensor components. The circularly polarized SFG methods are shown to be potentially useful coherent spectroscopic tools for determining absolute configurations of chiral molecules in condensed phases

  19. Asymmetric Vibrations of a Circular Elastic Plate on an Elastic Half Space

    DEFF Research Database (Denmark)

    Schmidt, H.; Krenk, Steen

    1982-01-01

    The asymmetric problem of a vibrating circular elastic plate in frictionless contact with an elastic half space is solved by an integral equation method, where the contact stress appears as the unknown function. By a trigonometric expansion, the problem is reduced to a number of uncoupled two...

  20. Study on the radial vibration and acoustic field of an isotropic circular ring radiator.

    Science.gov (United States)

    Lin, Shuyu; Xu, Long

    2012-01-01

    Based on the exact analytical theory, the radial vibration of an isotropic circular ring is studied and its electro-mechanical equivalent circuit is obtained. By means of the equivalent circuit model, the resonance frequency equation is derived; the relationship between the radial resonance frequency, the radial displacement amplitude magnification and the geometrical dimensions, the material property is analyzed. For comparison, numerical method is used to simulate the radial vibration of isotropic circular rings. The resonance frequency and the radial vibrational displacement distribution are obtained, and the radial radiation acoustic field of the circular ring in radial vibration is simulated. It is illustrated that the radial resonance frequencies from the analytical method and the numerical method are in good agreement when the height is much less than the radius. When the height becomes large relative to the radius, the frequency deviation from the two methods becomes large. The reason is that the exact analytical theory is limited to thin circular ring whose height must be much less than its radius. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Thermo-mechanical vibration analysis of annular and circular graphene sheet embedded in an elastic medium

    Directory of Open Access Journals (Sweden)

    M. Mohammadi

    Full Text Available In this study, the vibration behavior of annular and circular graphene sheet coupled with temperature change and under in-plane pre-stressed is studied. Influence of the surrounding elastic medium 011 the fundamental frequencies of the single-layered graphene sheets (SLGSs is investigated. Both Winkler-type and Pasternak- type models are employed to simulate the interaction of the graphene sheets with a surrounding elastic medium. By using the nonlocal elasticity theory the governing equation is derived for SLGSs. The closed-form solution for frequency vibration of circular graphene sheets lias been obtained and nonlocal parameter, inplane pre-stressed, the parameters of elastic medium and temperature change appears into arguments of Bessel functions. The results are subsequently compared with valid result reported in the literature and the molecular dynamics (MD results. The effects of the small scale, pre-stressed, mode number, temperature change, elastic medium and boundary conditions on natural frequencies are investigated. The non-dimensional frequency decreases at high temperature case with increasing the temperature change for all boundary conditions. The effect of temperature change 011 the frequency vibration becomes the opposite at high temperature case in compression with the low temperature case. The present research work thus reveals that the nonlocal parameter, boundary conditions and temperature change have significant effects on vibration response of the circular nanoplates. The present results can be used for the design of the next generation of nanodevices that make use of the thermal vibration properties of the graphene.

  2. Tunable plasmonic filter with circular metal–insulator– metal ring ...

    Indian Academy of Sciences (India)

    The mechanism based on circular ring resonators with narrow gaps may provide a novel method for designing all-optical integrated components in optical communication and computing. Keywords. Metal–insulator–metal waveguide; surface plasmon; optical filters; ring resonator. PACS Nos 42.79.−e; 73.20.Mf; 78.20.Bh. 1.

  3. Vibration Analysis of Circular Arch Element Using Curvature

    Directory of Open Access Journals (Sweden)

    H. Saffari

    2008-01-01

    Full Text Available In this paper, a finite element technique was used to determine the natural frequencies, and the mode shapes of a circular arch element was based on the curvature, which can fully represent the bending energy and by the equilibrium equations, the shear and axial strain energy were incorporated into the formulation. The treatment of general boundary conditions dose need a consideration when the element is incorporated by the curvature-based formula. This can be obtained by the introduction of a transformation matrix between nodal curvatures and nodal displacements. The equation of the motion for the element was obtained by the Lagrangian equation. Four examples are presented in order to verify the element formulation and its analytical capability.

  4. Anharmonic Vibrational Spectroscopy on Metal Transition Complexes

    Science.gov (United States)

    Latouche, Camille; Bloino, Julien; Barone, Vincenzo

    2014-06-01

    Advances in hardware performance and the availability of efficient and reliable computational models have made possible the application of computational spectroscopy to ever larger molecular systems. The systematic interpretation of experimental data and the full characterization of complex molecules can then be facilitated. Focusing on vibrational spectroscopy, several approaches have been proposed to simulate spectra beyond the double harmonic approximation, so that more details become available. However, a routine use of such tools requires the preliminary definition of a valid protocol with the most appropriate combination of electronic structure and nuclear calculation models. Several benchmark of anharmonic calculations frequency have been realized on organic molecules. Nevertheless, benchmarks of organometallics or inorganic metal complexes at this level are strongly lacking despite the interest of these systems due to their strong emission and vibrational properties. Herein we report the benchmark study realized with anharmonic calculations on simple metal complexes, along with some pilot applications on systems of direct technological or biological interest.

  5. Ab initio calculations of anharmonic vibrational circular dichroism intensities of trans-2,3-dideuteriooxirane

    DEFF Research Database (Denmark)

    Bak, KL; Bludsky, O.; Jorgensen, P

    1995-01-01

    A priori theory is derived for anharmonic calculations of vibrational circular dichroism (VCD). The anharmonic VCD expression is gauge origin independent and reduce to the magnetic field perturbation theory expression in the double-harmonic approximation. The theory has been implemented using...... for the atomic axial tensors and using second-order Moller-Plesset theory for the atomic polar tensors and the force fields, The changes of the vibrational rotatory strengths from anharmonicities are small, and do not explain the previously observed large discrepancies between the double-harmonic results...

  6. Electronic and vibrational circular dichroism spectra of (R)-(−)-apomorphine

    International Nuclear Information System (INIS)

    Abbate, Sergio; Longhi, Giovanna; Lebon, France; Tommasini, Matteo

    2012-01-01

    Highlights: ► ECD and VCD Spectra of (R)-(−)-apomorphine measured in various solvents. ► DFT calculations allow to study the protonation state and conformations. ► Contributions from catechol OH vibrations to the VCD spectra is studied. -- Abstract: Apomorphine is a chiral drug molecule; notwithstanding its extraordinary importance, little attention has been paid to the characterization of its chiroptical properties. Here we report on its electronic circular dichroism (ECD) spectra, recorded in methanol and water, and vibrational circular dichroism (VCD) in methanol and dimethyl sulfoxide (DMSO) solutions. Density functional theory (DFT) calculations have allowed us to interpret the spectra and to evaluate the role of possible conformations, charge-states and interactions with counter ions.

  7. Structural characterization of chiral molecules using vibrational circular dichroism spectroscopy

    DEFF Research Database (Denmark)

    Lassen, Peter Rygaard

    2006-01-01

    comparison of experimental and calculated spectra. Theoretical structures of the sample molecules were constructed and optimized using molecular mechanical force fields followed by the quantum mechanical method density functional theory (DFT). Calculations of IR absorption and VCD spectra were then carried...... out using the same DFT methods. Here, VCD has the advantage over CD that time-independent DFT calculations are sufficient. During the course of this project, the above methodology has been applied to a range of molecules. Some of them (nyasol, curcuphenol dimers and ginkgolide) are purely organic...... or as flexible as the curcuphenol dimer with 11 variable dihedral angles. This illustrates the capabilities of the method, which are primarily limited by the duration of DFT calculations. In the case of metal complexes, they have only recently become within reach of DFT, which opens new possibilities...

  8. Size-dependent axisymmetric vibration of functionally graded circular plates in bifurcation/limit point instability

    Science.gov (United States)

    Ashoori, A. R.; Vanini, S. A. Sadough; Salari, E.

    2017-04-01

    In the present paper, vibration behavior of size-dependent functionally graded (FG) circular microplates subjected to thermal loading are carried out in pre/post-buckling of bifurcation/limit-load instability for the first time. Two kinds of frequently used thermal loading, i.e., uniform temperature rise and heat conduction across the thickness direction are considered. Thermo-mechanical material properties of FG plate are supposed to vary smoothly and continuously throughout the thickness based on power law model. Modified couple stress theory is exploited to describe the size dependency of microplate. The nonlinear governing equations of motion and associated boundary conditions are extracted through generalized form of Hamilton's principle and von-Karman geometric nonlinearity for the vibration analysis of circular FG plates including size effects. Ritz finite element method is then employed to construct the matrix representation of governing equations which are solved by two different strategies including Newton-Raphson scheme and cylindrical arc-length method. Moreover, in the following a parametric study is accompanied to examine the effects of the several parameters such as material length scale parameter, temperature distributions, type of buckling, thickness to radius ratio, boundary conditions and power law index on the dimensionless frequency of post-buckled/snapped size-dependent FG plates in detail. It is found that the material length scale parameter and thermal loading have a significant effect on vibration characteristics of size-dependent circular FG plates.

  9. Vibrations of alkali metal overlayers on metal surfaces

    International Nuclear Information System (INIS)

    Rusina, G G; Eremeev, S V; Borisova, S D; Echenique, P M; Chulkov, E V; Benedek, G

    2008-01-01

    We review the current progress in the understanding of vibrations of alkalis adsorbed on metal surfaces. The analysis of alkali vibrations was made on the basis of available theoretical and experimental results. We also include in this discussion our recent calculations of vibrations in K/Pt(111) and Li(Na)/Cu(001) systems. The dependence of alkali adlayer localized modes on atomic mass, adsorption position and coverage as well as the dependence of vertical vibration frequency on the substrate orientation is discussed. The square root of atomic mass dependence of the vertical vibration energy has been confirmed by using computational data for alkalis on the Al(111) and Cu(001) substrates. We have confirmed that in a wide range of submonolayer coverages the stretch mode energy remains nearly constant while the energy of in-plane polarized modes increases with the increase of alkali coverage. It was shown that the spectrum of both stretch and in-plane vibrations can be very sensitive to the adsorption position of alkali atoms and substrate orientation

  10. Damping of edgewise vibration in wind turbine blades by means of circular liquid dampers

    DEFF Research Database (Denmark)

    Basu, Biswajit; Zhang, Zili; Nielsen, Søren R.K.

    2016-01-01

    centrifugal acceleration. This centrifugal acceleration makes the use of this kind of oscillatory liquid damper feasible with a small mass ratio to effectively suppress edgewise vibrations. A reduced 2-DOF non-linear model is used for tuning the CLCD attached to a rotating wind turbine blade, ignoring......This paper proposes a new type of passive vibration control damper for controlling edgewise vibrations of wind turbine blades. The damper is a variant of the liquid column damper and is termed as a circular liquid column damper (CLCD). Rotating wind turbine blades generally experience a large...... the coupling between the blade and the tower. The performance of the damper is evaluated under various rotational speeds of the rotor. A special case in which the rotational speed is so small that the gravity dominates the motion of the liquid is also investigated. Further, the legitimacy of the decoupled...

  11. Strouhal number effect on synchronized vibration range of a circular cylinder in cross flow

    International Nuclear Information System (INIS)

    Kawamura, T.; Nakao, T.; Hayashi, M.; Murayama, K.

    2001-01-01

    Synchronized vibrations were measured for a circular cylinder subjected to a water cross flow in the subcritical Reynolds numbers in order to compare the synchronized vibration range between the subcritical and supercritical regions and clarify the effect of the Strouhal number on it. A small peak vibration in the lift direction was found when the Karman vortex shedding frequency was about 1/5 of the cylinder natural frequency in only the subcritical region. The ratio of the Karman vortex frequency to the natural frequency where the self-excited vibration in the drag direction by the symmetrical vortices began was about 1/4 in the subcritical region, and increased to 0,32 at the Strouhal number of 0,29 in the supercritical region. The frequency ratio at the beginning of the lock-in vibration in the drag direction by the Karman vortex was about 1/2, and that in the lift direction decreased from 1 to about 0,8 with decreasing Strouhal number. (author)

  12. Asymmetric Vibration of Polar Orthotropic Annular Circular Plates of Quadratically Varying Thickness with Same Boundary Conditions

    Directory of Open Access Journals (Sweden)

    N. Bhardwaj

    2008-01-01

    Full Text Available In the present paper, asymmetric vibration of polar orthotropic annular circular plates of quadratically varying thickness resting on Winkler elastic foundation is studied by using boundary characteristic orthonormal polynomials in Rayleigh-Ritz method. Convergence of the results is tested and comparison is made with results already available in the existing literature. Numerical results for the first ten frequencies for various values of parameters describing width of annular plate, thickness profile, material orthotropy and foundation constant for all three possible combinations of clamped, simply supported and free edge conditions are shown and discussed. It is found that (a higher elastic property in circumferential direction leads to higher stiffness against lateral vibration; (b Lateral vibration characteristics of F-Fplates is more sensitive towards parametric changes in material orthotropy and foundation stiffness than C-C and S-Splates; (c Effect of quadratical thickness variation on fundamental frequency is more significant in cases of C-C and S-S plates than that of F-Fplates. Thickness profile which is convex relative to plate center-line tends to result in higher stiffness of annular plates against lateral vibration than the one which is concave and (d Fundamental mode of vibration of C-C and S-Splates is axisymmetrical while that of F-Fplates is asymmetrical.

  13. Assignment of absolute stereostructures through quantum mechanics electronic and vibrational circular dichroism calculations.

    Science.gov (United States)

    Dai, Peng; Jiang, Nan; Tan, Ren-Xiang

    2016-01-01

    Elucidation of absolute configuration of chiral molecules including structurally complex natural products remains a challenging problem in organic chemistry. A reliable method for assigning the absolute stereostructure is to combine the experimental circular dichroism (CD) techniques such as electronic and vibrational CD (ECD and VCD), with quantum mechanics (QM) ECD and VCD calculations. The traditional QM methods as well as their continuing developments make them more applicable with accuracy. Taking some chiral natural products with diverse conformations as examples, this review describes the basic concepts and new developments of QM approaches for ECD and VCD calculations in solution and solid states.

  14. Free vibration of symmetric angle-ply laminated circular cylindrical shells

    International Nuclear Information System (INIS)

    Viswanathan, K K; Aziz, Zainal Abdul; Amirah, H Z; Javed, Saira

    2014-01-01

    Free vibration of symmetric angle-ply laminated circular cylindrical shells is studied using Spline approximation. The equations of motions in longitudinal, circumferential and transverse displacement components, are derived using Love's first approximation theory. The coupled differential equations are solved using Spline approximation to obtain the generalized eigenvalue problem. Parametric studies are performed to analyse the frequency response of the shell with reference to the material properties, number of layers, ply orientation, length and circumferential node number and different boundary conditions

  15. Structure and Absolute Configuration of Nyasol and Hinokiresinol via Synthesis and Vibrational Circular Dichroism Spectroscopy

    DEFF Research Database (Denmark)

    Lassen, Peter Rygaard

    2005-01-01

    The absolute configuration of the norlignan (+)-nyasol was determined to be S by comparison of the experimental vibrational circular dichroism data with first-principle calculations taking into account the eight lowest energy conformations. The established absolute configuration of (+)-nyasol...... enables establishment of the absolute configuration of (-)-hinokiresinol, which is concluded to be S. A total synthesis and resolution of hinokiresinol has been performed to resolve the conflicting reports of the coupling constant of the vinylic protons of the disubstituted double bond in this molecule...

  16. Sensing site-specific structural characteristics and chirality using vibrational circular dichroism of isotope labeled peptides.

    Science.gov (United States)

    Keiderling, Timothy A

    2017-12-01

    Isotope labeling has a long history in chemistry as a tool for probing structure, offering enhanced sensitivity, or enabling site selection with a wide range of spectroscopic tools. Chirality sensitive methods such as electronic circular dichroism are global structural tools and have intrinsically low resolution. Consequently, they are generally insensitive to modifications to enhance site selectivity. The use of isotope labeling to modify vibrational spectra with unique resolvable frequency shifts can provide useful site-specific sensitivity, and these methods have been recently more widely expanded in biopolymer studies. While the spectral shifts resulting from changes in isotopic mass can provide resolution of modes from specific parts of the molecule and can allow detection of local change in structure with perturbation, these shifts alone do not directly indicate structure or chirality. With vibrational circular dichroism (VCD), the shifted bands and their resultant sign patterns can be used to indicate local conformations in labeled biopolymers, particularly if multiple labels are used and if their coupling is theoretically modeled. This mini-review discusses selected examples of the use of labeling specific amides in peptides to develop local structural insight with VCD spectra. © 2017 Wiley Periodicals, Inc.

  17. Vibrational mode and sound radiation of electrostatic speakers using circular and annular diaphragms

    Science.gov (United States)

    Huang, Yu-Hsi; Chiang, Hsin-Yuan

    2016-06-01

    This study modeled two diaphragms comprising a pair of indium tin oxide (ITO) transparent plates sandwiching a vibrating diaphragm to create circular (30 mm radius) and annular (30 mm outer and 3 mm inner radius) push-pull electrostatic speakers. We then measured the displacement amplitudes and mode shapes produced by the devices. Vibration characteristics were used to predict sound pressure levels (SPLs) using the lumped parameter method (LPM) and distributed parameter method (DPM). The two measurement results obtained using a laser system were compared to the SPLs obtained using traditional acoustic measurement (AM) from 20 Hz to 20 kHz in order to verify our predictions. When using LPM and DPM, the SPL prediction results in the first three symmetric modes were in good agreement with the AM results. Under the assumption of linear operations, the DPM and amplitude-fluctuation electronic speckle pattern interferometry (ESPI) techniques proved effective in determining the visualization of mode shape (0,1)-(0,3). The use of ITO plates is a practical technique for the prediction of SPL, as well as measurement of mode shapes. The four evaluation methods, i.e. LPM, DPM, ESPI and AM, present a high degree of consistency with regard to vibrational mode and sound radiation characteristics.

  18. On vortex shedding and prediction of vortex-induced vibrations of circular cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Halse, Karl Henning

    1998-12-31

    In offshore installations, many crucial components can be classified as slender marine structures: risers, mooring lines, umbilicals and cables, pipelines. This thesis studies the vortex shedding phenomenon and the problem of predicting vortex-induced vibrations of such structures. As the development of hydrocarbons move to deeper waters, the importance of accurately predicting the vortex-induced response has increased and so the need for proper response prediction methods is large. This work presents an extensive review of existing research publications about vortex shedding from circular cylinders and the vortex-induced vibrations of cylinders and the different numerical approaches to modelling the fluid flow. The response predictions from different methods are found to disagree, both in response shapes and in vibration amplitudes. This work presents a prediction method that uses a fully three-dimensional structural finite element model integrated with a laminar two-dimensional Navier-Stokes solution modelling the fluid flow. This solution is used to study the flow both around a fixed cylinder and in a flexibly mounted one-degree-of-freedom system. It is found that the vortex-shedding process (in the low Reynolds number regime) is well described by the computer program, and that the vortex-induced vibration of the flexibly mounted section do reflect the typical dynamic characteristics of lock-in oscillations. However, the exact behaviour of the experimental results found in the literature was not reproduced. The response of the three-dimensional structural model is larger than the expected difference between a mode shape and a flexibly mounted section. This is due to the use of independent hydrodynamic sections along the cylinder. The predicted response is not unrealistic, and the method is considered a powerful tool. 221 refs., 138 figs., 36 tabs.

  19. On vortex shedding and prediction of vortex-induced vibrations of circular cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Halse, Karl Henning

    1997-12-31

    In offshore installations, many crucial components can be classified as slender marine structures: risers, mooring lines, umbilicals and cables, pipelines. This thesis studies the vortex shedding phenomenon and the problem of predicting vortex-induced vibrations of such structures. As the development of hydrocarbons move to deeper waters, the importance of accurately predicting the vortex-induced response has increased and so the need for proper response prediction methods is large. This work presents an extensive review of existing research publications about vortex shedding from circular cylinders and the vortex-induced vibrations of cylinders and the different numerical approaches to modelling the fluid flow. The response predictions from different methods are found to disagree, both in response shapes and in vibration amplitudes. This work presents a prediction method that uses a fully three-dimensional structural finite element model integrated with a laminar two-dimensional Navier-Stokes solution modelling the fluid flow. This solution is used to study the flow both around a fixed cylinder and in a flexibly mounted one-degree-of-freedom system. It is found that the vortex-shedding process (in the low Reynolds number regime) is well described by the computer program, and that the vortex-induced vibration of the flexibly mounted section do reflect the typical dynamic characteristics of lock-in oscillations. However, the exact behaviour of the experimental results found in the literature was not reproduced. The response of the three-dimensional structural model is larger than the expected difference between a mode shape and a flexibly mounted section. This is due to the use of independent hydrodynamic sections along the cylinder. The predicted response is not unrealistic, and the method is considered a powerful tool. 221 refs., 138 figs., 36 tabs.

  20. Free vibration analysis of multi directional functionally graded circular and annular plates

    Energy Technology Data Exchange (ETDEWEB)

    Kermani, Iman Davoodi; Ghayour, Mostafa; Mirdamadi, Hamid Reza [Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of)

    2012-11-15

    This paper addresses the free vibration of multi directional functionally graded circular and annular plates using a semianalytical/numerical method, called state space based differential quadrature method. Three-dimensional elasticity equations are derived for multi directional functionally graded plates and a solution is given by the semi-analytical/numerical method. This method gives an analytical solution along the thickness direction, using a state space method and a numerical solution using differential quadrature method. Some numerical examples are presented to show the accuracy and convergence of the method. The most of simulations of the present study have been validated by the existing literature. The non dimensional frequencies and corresponding displacements mode shapes are obtained. Then the influences of thickness ratio and graded indexes are demonstrated on the non dimensional natural frequencies.

  1. Non-axisymmetric flexural vibrations of free-edge circular silicon wafers

    Energy Technology Data Exchange (ETDEWEB)

    Dmitriev, A.V., E-mail: dmitriev@hbar.phys.msu.ru; Gritsenko, D.S.; Mitrofanov, V.P., E-mail: mitr@hbar.phys.msu.ru

    2014-02-07

    Non-axisymmetric flexural vibrations of circular silicon (111) wafers are investigated. The modes with azimuthal index 2⩽k⩽30 are electrostatically excited and monitored by a capacitive sensor. The splitting of the mode frequencies associated with imperfection of the wafer is observed. The measured loss factors for the modes with 6≲k≲26 are close to those calculated according to the thermoelastic damping theory, while clamping losses likely dominate for k≲6, and surface losses at the level of inverse Q-factor Q{sup −1}≈4×10{sup −6} prevail for the modes with large k. The modes demonstrate nonlinear behavior of mainly geometrical origin at large amplitudes.

  2. Explicit Consideration of Water Molecules to Study Vibrational Circular DICHROÎSM of Monosaccharide's

    Science.gov (United States)

    Moussi, Sofiane; Ouamerali, Ourida

    2014-06-01

    Carbohydrates have multiples roles in biological systems. It has been found that the glycoside bond is fundamentally important in many aspects of chemistry and biology and forms the basis of carbohydrate chemistry. That means the stereochemical information, namely, glycosidic linkages α or β, gives an significant features of the carbohydrate glycosidation position of the glycosylic acceptor. For these reasons, much effort was made for the synthesis and analysis of the glycoside bond. Vibrational circular dichroism VCD has some advantages over conventional electronic circular dichroism (ECD) due to the applicability to all organic molecules and the reliability of ab initio quantum calculation. However, for a molecule with many chiral centers such as carbohydrates, determination of the absolute configuration tends to be difficult because the information from each stereochemical center is mixed and averaged over the spectrum. In the CH stretching region, only two VCD studies on carbohydrates have been reported and spectra--structure correlation, as determined for the glycoside band, remains to be investigated. T. Taniguchi and collaborators report that methyl glycosides exhibit a characteristic VCD peak, the sign of which solely reflects the C-1 absolute configuration. This work is a theoretical contribution to study the behaviour of VCD spectrum's of the monosaccharides when the water molecules are taken explicitly. This study is focused on six different monosaccharides in theirs absolute configuration R and S. We used the method of density functional theory DFT by means of the B3LYP hybrid functional and 6-31G * basis set.

  3. Synthesis and vibrational circular dichroism of enantiopure chiral oxorhenium(V) complexes containing the hydrotris(1-pyrazolyl)borate ligand

    DEFF Research Database (Denmark)

    Lassen, Peter Rygaard

    2006-01-01

    The infrared and vibrational circular dichroism (VCD) spectra of six chiral oxorhenium(V) complexes, bearing a hydrotris(1-pyrazolyl)borate (Tp) ligand, have been investigated. These complexes are promising candidates for observation of parity violation (symmetry breaking due to the weak nuclear...

  4. Frequency Equations for the In-Plane Vibration of Circular Annular Disks

    Directory of Open Access Journals (Sweden)

    S. Bashmal

    2010-01-01

    Full Text Available This paper deals with the in-plane vibration of circular annular disks under combinations of different boundary conditions at the inner and outer edges. The in-plane free vibration of an elastic and isotropic disk is studied on the basis of the two-dimensional linear plane stress theory of elasticity. The exact solution of the in-plane equation of equilibrium of annular disk is attainable, in terms of Bessel functions, for uniform boundary conditions. The frequency equations for different modes can be obtained from the general solutions by applying the appropriate boundary conditions at the inner and outer edges. The presented frequency equations provide the frequency parameters for the required number of modes for a wide range of radius ratios and Poisson's ratios of annular disks under clamped, free, or flexible boundary conditions. Simplified forms of frequency equations are presented for solid disks and axisymmetric modes of annular disks. Frequency parameters are computed and compared with those available in literature. The frequency equations can be used as a reference to assess the accuracy of approximate methods.

  5. Vibrationally induced inversion of photoelectron forward-backward asymmetry in chiral molecule photoionization by circularly polarized light

    Science.gov (United States)

    Garcia, Gustavo A.; Nahon, Laurent; Daly, Steven; Powis, Ivan

    2013-01-01

    Electron–nuclei coupling accompanying excitation and relaxation processes is a fascinating phenomenon in molecular dynamics. A striking and unexpected example of such coupling is presented here in the context of photoelectron circular dichroism measurements on randomly oriented, chiral methyloxirane molecules, unaffected by any continuum resonance. Here, we report that the forward-backward asymmetry in the electron angular distribution, with respect to the photon axis, which is associated with photoelectron circular dichroism can surprisingly reverse direction according to the ion vibrational mode excited. This vibrational dependence represents a clear breakdown of the usual Franck–Condon assumption, ascribed to the enhanced sensitivity of photoelectron circular dichroism (compared with other observables like cross-sections or the conventional anisotropy parameter-β) to the scattering phase off the chiral molecular potential, inducing a dependence on the nuclear geometry sampled in the photoionization process. Important consequences for the interpretation of such dichroism measurements within analytical contexts are discussed. PMID:23828557

  6. Enantioselective semi-preparative HPLC separation of PCB metabolites and their absolute structures determined by electronic and vibrational circular dichroism

    Energy Technology Data Exchange (ETDEWEB)

    Tuan, H.P.; Larsson, C.; Huehnerfuss, H. [Hamburg Univ. (Germany). Inst. fuer Organische Chemie; Hoffmann, F.; Froeba, M. [Giessen Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Bergmann, Aa. [Stockholm Univ. (Sweden). Dept. of Environmental Chemistry

    2004-09-15

    The present paper represents a first result of an ongoing systematic study of atropisomeric methylsulfonyl, methylthionyl, hydroxy, and methoxy metabolites of environmentally most relevant PCBs. This involves semi-preparative enantioselective HPLC separation to obtain pure atropisomers from synthesized PCB metabolite standards, their configuration estimation using the electronic circular dichroism (UV-CD) method and the determination / confirmation of these absolute configurations applying the combined vibrational circular dichroism (VCD) / ab initio approach. The following substances have been investigated: 4-HO-, 4-MeO-, 4-MeS-, 4-MeSO2-, 3-MeS- and 3-MeSO{sub 2}-CB149.

  7. Research on the equivalent circuit model of a circular flexural-vibration-research on the equivalent circuit model of a circular flexural-vibration-mode piezoelectric transformer with moderate thickness.

    Science.gov (United States)

    Huang, Yihua; Huang, Wenjin; Wang, Qinglei; Su, Xujian

    2013-07-01

    The equivalent circuit model of a piezoelectric transformer is useful in designing and optimizing the related driving circuits. Based on previous work, an equivalent circuit model for a circular flexural-vibration-mode piezoelectric transformer with moderate thickness is proposed and validated by finite element analysis. The input impedance, voltage gain, and efficiency of the transformer are determined through computation. The basic behaviors of the transformer are shown by numerical results.

  8. Examination of hydrodynamic force acting on a circular cylinder in vortex-induced vibrations in synchronization

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Linwei; Sun, Zhilin [Ocean College, Zhejiang University, Zhoushan, 316021 (China); Chan, Eng-Soon, E-mail: shenlinwei@zju.edu.cn [Department of Civil and Environmental Engineering, National University of Singapore, No. 1 Engineering Drive 2, Singapore 117576 (Singapore)

    2017-04-15

    An immersed boundary method is employed to simulate vortex-induced vibrations (VIV) of a circular cylinder in two dimensions. The Reynolds number is 150, and the cylinder mass ratios of 2 and 10 are considered. The synchronization regions for these two mass ratios are determined by the simulations. It is found that the cycle-averaged added mass is about zero at the reduced velocity of 6.1. The instantaneous frequency, which is obtained by Hilbert transformation of the cylinder oscillating displacement, exhibits an important feature whereby the cylinder oscillation in the VIV synchronization region is modulated with a frequency twice the displacement prevailing frequency. The cylinder displacement could still be well approximated by a sine function with a constant frequency and amplitude. However, the lift force acting on the cylinder cannot be estimated in the same manner. In fact, both the lift force amplitude and frequency are modulated. The suggested expression provides a better approximation of the lift force. Moreover, it reveals that the presence of the higher harmonics in the lift force is the result of the amplitude and frequency modulation. (paper)

  9. Improved vibration-based energy harvesting by annular mass configuration of piezoelectric circular diaphragms

    Science.gov (United States)

    Yang, Yangyiwei; Li, Yuanbo; Guo, Yaqian; Xu, Bai-Xiang; Yang, Tongqing

    2018-03-01

    Vibration-based energy harvesting using piezoelectric circular diaphragms (PCDs) with a structure featuring the central mass (C-mass) configuration has drawn much attention in recent decades. In this work, we propose a new configuration with the annular proof mass (A-mass) where an improved energy harvesting is promised. The numerical analysis was employed using the circuit-coupled piezoelectric simulation, and the experimental validation was implemented using PCDs with the even-width annular electrodes. Samples with the different mass configurations as well as structural parameters ϖ 1 and ϖ 2, which indicate the ratio between the inner boundary radius and piezoelectric ceramic radius as well as the ratio between outer boundary radius and the substrate radius, respectively, were prepared and tested. The impedance-matched output power of full-electrode PCDs was also collected, and some distinct improvement was measured on samples with the certain structural parameters. The power increases from 14.1 mW to 19.0 mW after changing the configuration from C-mass to A-mass with the same parameters (ϖ 1, ϖ 2) = (0.16, 0.9), showing the considerable improvement in energy harvesting by using A-mass configuration.

  10. Beating motion of a circular cylinder in vortex-induced vibrations

    Science.gov (United States)

    Shen, Linwei; Chan, Eng-Soon; Wei, Yan

    2018-04-01

    In this paper, beating phenomenon of a circular cylinder in vortex-induced vibration is studied by numerical simulations in a systematic manner. The cylinder mass coefficients of 2 and 10 are considered, and the Reynolds number is 150. Two distinctive frequencies, namely cylinder oscillation and vortex shedding frequencies, are obtained from the harmonic analysis of the cylinder displacement. The result is consistent with that observed in laboratory experiments. It is found that the cylinder oscillation frequency changes with the natural frequency of the cylinder while the reduced velocity is varied. The added-mass coefficient of the cylinder in beating motion is therefore estimated. Meanwhile, the vortex shedding frequency does not change dramatically in the beating situations. In fact, it is very close to 0.2. Accordingly, the lift force coefficient has two main components associated with these two frequencies. Besides, higher harmonics of the cylinder oscillation frequency appear in the spectrum of the lift coefficient. Moreover, the vortex shedding timing is studied in the beating motion by examining the instantaneous flow fields in the wake, and two scenarios of the vortex formation are observed.

  11. Absolute Configuration of 3-METHYLCYCLOHEXANONE by Chiral Tag Rotational Spectroscopy and Vibrational Circular Dichroism

    Science.gov (United States)

    Evangelisti, Luca; Holdren, Martin S.; Mayer, Kevin J.; Smart, Taylor; West, Channing; Pate, Brooks

    2017-06-01

    The absolute configuration of 3-methylcyclohexanone was established by chiral tag rotational spectroscopy measurements using 3-butyn-2-ol as the tag partner. This molecule was chosen because it is a benchmark measurement for vibrational circular dichroism (VCD). A comparison of the analysis approaches of chiral tag rotational spectroscopy and VCD will be presented. One important issue in chiral analysis by both methods is the conformational flexibility of the molecule being analyzed. The analysis of conformational composition of samples will be illustrated. In this case, the high spectral resolution of molecular rotational spectroscopy and potential for spectral simplification by conformational cooling in the pulsed jet expansion are advantages for chiral tag spectroscopy. The computational chemistry requirements for the two methods will also be discussed. In this case, the need to perform conformer searches for weakly bound complexes and to perform reasonably high level quantum chemistry geometry optimizations on these complexes makes the computational time requirements less favorable for chiral tag rotational spectroscopy. Finally, the issue of reliability of the determination of the absolute configuration will be considered. In this case, rotational spectroscopy offers a "gold standard" analysis method through the determination of the ^{13}C-subsitution structure of the complex between 3-methylcyclohexanone and an enantiopure sample of the 3-butyn-2-ol tag.

  12. Free vibration analysis of a rotary smart two directional functionally graded piezoelectric material in axial symmetry circular nanoplate

    Science.gov (United States)

    Mahinzare, Mohammad; Ranjbarpur, Hosein; Ghadiri, Majid

    2018-02-01

    In this article, free vibration of a rotating circular nanoplate made of two directional functionally graded piezo materials (two directional FGPM) is modeled based on the first shear deformation theory (FSDT). Based on the power-law model, electro-elastic properties of two directional FGP rotating circular nanoplates are supposed to change continuously along the thickness and radius. Employing the modified couple stress theory, the small size effect of the equations of the plate is considered. The governing equations of the first shear deformation theory (FSDT) for the studied plate are obtained based on Hamilton's principle; these equations are solved using differential quadrature method (DQM). It is shown that the vibration behavior of the plate is significantly affected by angular velocity, external electric voltage, size dependency and power-law index (thickness and radial directions).

  13. METAL:LIC target failure diagnostics by means of liquid metal loop vibrations monitoring

    International Nuclear Information System (INIS)

    Dementjevs, S.; Barbagallo, F.; Wohlmuther, M.; Thomsen, K.; Zik, A.; Nikoluskins, R.

    2014-01-01

    A target mock-up, developed as an European Spallation Source comparative solution, (METAL:LIC) has been tested in a dedicated lead bismuth eutectic (LBE) loop in the Institute of Physics at the University of Latvia. In particular, the feasibility of diagnostic vibration monitoring has been investigated. The loop parameters were: operation temperature 300°C; tubing ∅100 mm, overall length 8 m; electromagnetic pump based on permanent magnets, flow rate 180 kg/s. With sufficient static pressure of a few bars, cavitation was avoided. The vibrations in the loop were measured and analyzed. Several vibrational characteristics of the set-up were derived including resonance frequencies and the dependence of excited vibrations on flow conditions and the pump rotation speed. A high sensitivity to obstructions in the loop has been confirmed, and several indicators for target failure diagnostics were tested and compared. A problem in the electromagnetic pump's gear box has been detected in a very early state long before it manifested itself in the operation of the loop. The vibration monitoring has been demonstrated as a sensitive and reliable probe for the target failure diagnostics. (author)

  14. The Effect of Non-Circular Bearing Shapes in Hydrodynamic Journal Bearings on the Vibration Behavior of Turbocharger Structures

    Directory of Open Access Journals (Sweden)

    Lukas Bernhauser

    2017-03-01

    Full Text Available Increasing quality demands of combustion engines require, amongst others, improvements of the engine’s acoustics and all (subcomponents mounted to the latter. A significant impact to the audible tonal noise spectrum results from the vibratory motions of fast-rotating turbocharger rotor systems in multiple hydrodynamic bearings such as floating bearing rings. Particularly, the study of self-excited non-linear vibrations of the rotor-bearing systems is crucial for the understanding, prevention or reduction of the noise and, consequently, for a sustainable engine acoustics development. This work presents an efficient modeling approach for the investigation, optimization, and design improvement of complex turbocharger rotors in hydrodynamic journal bearings, including floating bearing rings with circular and non-circular bearing geometries. The capability of tonal non-synchronous vibration prevention using non-circular bearing shapes is demonstrated with dynamic run-up simulations of the presented model. These findings and the performance of our model are compared and validated with results of a classical Laval/Jeffcott rotor-bearing model and a specific turbocharger model found in the literature. It is shown that the presented simulation method yields fast and accurate results and furthermore, that non-circular bearing shapes are an effective measure to reduce or even prevent self-excited tonal noise.

  15. Structural and vibrational studies of clean and chemisorbed metal surfaces

    International Nuclear Information System (INIS)

    Jiang, Qing-Tang.

    1992-01-01

    Using Medium Energy Ion Scattering, we have studied the structural and vibrational properties of a number of clean and chemisorbed metal surfaces. The work presented in this thesis is mainly of a fundamental nature. However, it is believed that an atomistic understanding of the forces that affect surface structural and vibrational properties can have a beneficial impact on a large number of areas of applied nature. We find that the surface structure of Cu(001) follows the common trend for metal surfaces, where a small oscillatory relaxation exists beginning with a slight contraction in the top layer. In addition, the surface vibrational amplitude is enhanced (as s usually the case) by ∼80%. A detailed analysis of our data shows an unexpected anisotropy of the vibrational amplitude, such that the out-of-plane vibrational amplitude is 30% smaller than the in-plane vibrational amplitude. The unexpected results may imply a large tensile stress on Cu(001). Upon adsorption of 1/4 of a monolayer of S, a p(2 x 2)-S/Cu(001) surface is created. This submonolayer amount of S atoms makes the surface bulk-like, in which the anisotropy of the surface vibrations is removed and the first interlayer contraction is lifted. By comparing our model to earlier contradictory results on this controversial system. We find excellent agreement with a recent LEED study. The presence of 0.1 monolayer of Ca atoms on the Au(113) surface induces a drastic atomic rearrangements, in which half of the top layer Au atoms are missing and a (1 x 2) symmetry results. In addition, the first interlayer spacing of Au(113) is significantly reduced. Our results are discussed in terms of the energy balance between competing surface electronic charge densities

  16. Launching focused surface plasmon in circular metallic grating

    International Nuclear Information System (INIS)

    Kumar, Pawan; Tripathi, V. K.; Kumar, Ashok; Shao, X.

    2015-01-01

    The excitation of focused surface plasma wave (SPW) over a metal–vacuum interface embedded with circular surface grating is investigated theoretically. The normally impinged radiation imparts oscillatory velocity to free electrons that beats with the surface ripple to produce a nonlinear current, driving the SPW. As SPW propagates, it gets focused. The focused radiation has a maximum at the centre of grating and decreases beyond the centre due to diffraction. The amplitude of SPW is fixed for a given groove depth and increases rapidly around the resonance frequency. The intensity at the focus point depends on dimensions of the grating. It increases with the radiation frequency approaching the surface plasmon resonance. The scheme has potential applications for photonic devices and surface enhanced Raman scattering

  17. ANALYSIS OF NONMAGNETIC METAL INDUCTION HEATING PROCESSES BY FLAT-TYPE CIRCULAR SOLENOIDAL FIELD

    Directory of Open Access Journals (Sweden)

    Yu. Batygin

    2016-12-01

    Full Text Available The article analyzes the electromagnetic processes in the system of induction heating with estimating the main characteristics of heating the non-magnetic sheet metal. The analytical expressions for numerical estimates of the induced current in terms of the phase of the excitation signal are presented. The dependence for the heating temperature of the considered circular sheet metal area for the time corresponding to the interval phase has been determined.

  18. Hot-rolling metals in vacuum. Information circular

    International Nuclear Information System (INIS)

    Beall, R.A.; Worthington, R.B.; Blickensderfer, R.

    1979-01-01

    The process of hot-rolling metals, alloys, and composites in vacuum is studied. First, a comprehensive review of the literature is presented, including the advantages and disadvantages of using vacuum. Next, details of hot-rolling titanium, chromium, and molybdenum-iron bimetal are given. Finally, the design of new equipment is described

  19. Flow induced vibrations in liquid metal fast breeder reactors

    International Nuclear Information System (INIS)

    1989-01-01

    Flow induced vibrations are well known phenomena in industry. Engineers have to estimate their destructive effects on structures. In the nuclear industry, flow induced vibrations are assessed early in the design process, and the results are incorporated in the design procedures. In many cases, model testing is used to supplement the design process to ensure that detrimental behaviour due to flow induced vibrations will not occur in the component in question. While these procedures attempt to minimize the probability of adverse performance of the various components, there is a problem in the extrapolation of analytical design techniques and/or model testing to actual plant operation. Therefore, sodium tests or vibrational measurements of components in the reactor system are used to provide additional assurance. This report is a general survey of experimental and calculational methods in this area of structural mechanics. The report is addressed to specialists and institutions in industrialized and developing countries who are responsible for the design and operation of liquid metal fast breeder reactors. 92 refs, 90 figs, 8 tabs

  20. Chirality Transfer in Magnetic Coordination Complexes Monitored by Vibrational and Electronic Circular Dichroism

    Czech Academy of Sciences Publication Activity Database

    Wu, T.; Zhang, X. P.; You, X. Z.; Li, Y. Z.; Bouř, Petr

    2014-01-01

    Roč. 79, č. 5 (2014), s. 698-707 ISSN 2192-6506 Institutional support: RVO:61388963 Keywords : chirality * circular dichroism * iron * magnetic properties * Schiff bases Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.997, year: 2014

  1. Vibrational and electronic circular dichroism as powerful tools for the conformational analysis of cationic antimicrobial peptides

    Czech Academy of Sciences Publication Activity Database

    Kocourková, L.; Novotná, P.; Šťovíčková-Habartová, L.; Čujová, Sabína; Čeřovský, Václav; Urbanová, M.; Setnička, V.

    2016-01-01

    Roč. 147, č. 8 (2016), s. 1439-1445 ISSN 0026-9247 Institutional support: RVO:61388963 Keywords : conformation * circular dichroism * antimicrobial peptides * liposomes * infrared spectroscopy Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.282, year: 2016

  2. Vibration of an Elastic Circular Plate on an Elastic Half Space

    DEFF Research Database (Denmark)

    Krenk, Steen; Schmidt, H.

    1981-01-01

    The axisymmetric problem of a vibrating elastic plate on an elastic half space is solved by a direct method, in which the contact stresses and the normal displacements of the plate are taken as the unknown functions. First, the influence functions that give the displacements in terms...

  3. Thermolysis of (1R,2R)-1,2-dideuteriocyclobutane. An application of vibrational circular dichroism to kinetic analysis

    International Nuclear Information System (INIS)

    Chickos, J.S.; Annamalai, A.; Keiderling, T.A.

    1986-01-01

    The relative rates of geometric isomerization to racemization have been studied for the title compound by using a combination of infrared (IR) and vibrational circular dichroism (VCD) spectroscopies, respectively. The results are interpreted with a kinetic and mechanistic scheme which parallels that used by Berson, Pedersen, and Carpenter on a similar study of chiral cyclopropane-d 2 thermolysis. Relative rates of isomerization to stereomutation of 1.5 +/- 0.4 were obtained which can be interpreted to be consistent with a mechanism best described by random methylene rotation in tetramethylene-d 2 . This is the first application of VCD to kinetic analysis, and the advantages of IR techniques over the more usually employed UV spectroscopies to this type of basic mechanistic problem are illustrated

  4. Conformational analysis of quinine and its pseudo enantiomer quinidine: a combined jet-cooled spectroscopy and vibrational circular dichroism study.

    Science.gov (United States)

    Sen, Ananya; Bouchet, Aude; Lepère, Valeria; Le Barbu-Debus, Katia; Scuderi, D; Piuzzi, F; Zehnacker-Rentien, A

    2012-08-16

    Laser-desorbed quinine and quinidine have been studied in the gas phase by combining supersonic expansion with laser spectroscopy, namely, laser-induced fluorescence (LIF), resonance-enhanced multiphoton ionization (REMPI), and IR-UV double resonance experiments. Density funtional theory (DFT) calculations have been done in conjunction with the experimental work. The first electronic transition of quinine and quinidine is of π-π* nature, and the studied molecules weakly fluoresce in the gas phase, in contrast to what was observed in solution (Qin, W. W.; et al. J. Phys. Chem. C2009, 113, 11790). The two pseudo enantiomers quinine and quinidine show limited differences in the gas phase; their main conformation is of open type as it is in solution. However, vibrational circular dichroism (VCD) experiments in solution show that additional conformers exist in condensed phase for quinidine, which are not observed for quinine. This difference in behavior between the two pseudo enantiomers is discussed.

  5. Vibrational Structure in Magnetic Circular Dichroism Spectra of Polycyclic Aromatic Hydrocarbons

    Czech Academy of Sciences Publication Activity Database

    Kaminský, Jakub; Chalupský, Jakub; Štěpánek, P.; Kříž, Jan; Bouř, Petr

    2017-01-01

    Roč. 121, č. 47 (2017), s. 9064-9073 ISSN 1089-5639 R&D Projects: GA ČR GA15-19143S; GA ČR(CZ) GA16-05935S; GA ČR(CZ) GA16-00270S Institutional support: RVO:61388963 Keywords : magnetic circular dichroism * polycyclic aromatic hydrocarbons * DFT Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 2.847, year: 2016

  6. Circular Economy: Questions for Responsible Minerals, Additive Manufacturing and Recycling of Metals

    Directory of Open Access Journals (Sweden)

    Damien Giurco

    2014-05-01

    Full Text Available The concept of the circular economy proposes new patterns of production, consumption and use, based on circular flows of resources. Under a scenario where there is a global shift towards the circular economy, this paper discusses the advent of two parallel and yet-to-be-connected trends for Australia, namely: (i responsible minerals supply chains and (ii additive manufacturing, also known as 3D production systems. Acknowledging the current context for waste management, the paper explores future interlinked questions which arise in the circular economy for responsible supply chains, additive manufacturing, and metals recycling. For example, where do mined and recycled resources fit in responsible supply chains as inputs to responsible production? What is required to ensure 3D production systems are resource efficient? How could more distributed models of production, enabled by additive manufacturing, change the geographical scale at which it is economic or desirable to close the loop? Examples are given to highlight the need for an integrated research agenda to address these questions and to foster Australian opportunities in the circular economy.

  7. Transitions in Theory and Practice: Managing Metals in the Circular Economy

    Directory of Open Access Journals (Sweden)

    Melissa Jackson

    2014-07-01

    Full Text Available Transitioning from current resource management practice dominated by linear economic models of consumption and production, to circular models of resource use, will require insights into the stages and processes associated with socio-technical transitions. This paper is concerned with transitions in practice. It explores two frameworks within the transitions literature—the multi-level perspective and transition management theory—for practical guidance to inform a deliberate transition in practice. The critical futures literature is proposed as a source of tools and methods to be used in conjunction with the transition frameworks to influence and enable transitions in practice. This enhanced practical guidance for initiating action is applied to a specific context—transitioning the Australian metals sector towards a circular economy model. This particular transition case study is relevant because the vision of a circular economy model of resource management is gaining traction internationally, Australia is significant globally as a supplier of finite mineral resources and it will also be used in a collaborative research project on Wealth from Waste to investigate possibilities for the circular economy and metals recycling.

  8. A circular feature-based pose measurement method for metal part grasping

    International Nuclear Information System (INIS)

    Wu, Chenrui; He, Zaixing; Zhang, Shuyou; Zhao, Xinyue

    2017-01-01

    The grasping of circular metal parts such as bearings and flanges is a common task in industry. Limited by low texture and repeated features, the point-feature-based method is not applicable in pose measurement of these parts. In this paper, we propose a novel pose measurement method for grasping circular metal parts. This method is based on cone degradation and involves a monocular camera. To achieve higher measurement accuracy, a position-based visual servoing method is presented to continuously control an eye-in-hand, six-degrees-of-freedom robot arm to grasp the part. The uncertainty of the part’s coordinate frame during the control process is solved by defining a fixed virtual coordinate frame. Experimental results are provided to illustrate the effectiveness of the proposed method and the factors that affect measurement accuracy are analyzed. (paper)

  9. Determination of the Absolute Configurations Using Exciton Chirality Method for Vibrational Circular Dichroism: Right Answers for the Wrong Reasons?

    Science.gov (United States)

    Covington, Cody L; Nicu, Valentin P; Polavarapu, Prasad L

    2015-10-22

    Quantum chemical (QC) predictions of vibrational circular dichroism (VCD) spectra for the keto form of 3-benzoylcamphor and conformationally flexible diacetates of spiroindicumide A and B are presented. The exciton chirality (EC) model has been briefly reviewed, and a procedure to evaluate the relevance of the EC model has been presented. The QC results are compared with literature experimental VCD spectra as well as with those obtained using the EC model for VCD. These comparisons reveal that the EC contributions to bisignate VCD couplets associated with the C═O stretching vibrations of benzoylcamphor, spiroindicumide A diacetate, and spiroindicumide B diacetate are only ∼30%, ∼3%, and ∼15%, respectively. With such meager EC contributions, the correct absolute configurations (ACs) suggested in the literature for spiroindicumide A diacetate and spiroindicumide B diacetate molecules using the EC concepts can be considered fortuitous. The possibilities for obtaining wrong AC predictions using the EC concepts for VCD are identified, and guidelines for the future use of this model are presented.

  10. Numerical analysis of liquid metal MHD flows through circular pipes based on a fully developed modeling

    International Nuclear Information System (INIS)

    Zhang, Xiujie; Pan, Chuanjie; Xu, Zengyu

    2013-01-01

    Highlights: ► 2D MHD code based on a fully developed modeling is developed and validated by Samad analytical results. ► The results of MHD effect of liquid metal through circular pipes at high Hartmann numbers are given. ► M type velocity profile is observed for MHD circular pipe flow at high wall conductance ratio condition. ► Non-uniform wall electrical conductivity leads to high jet velocity in Robert layers. -- Abstract: Magnetohydrodynamics (MHD) laminar flows through circular pipes are studied in this paper by numerical simulation under the conditions of Hartmann numbers from 18 to 10000. The code is developed based on a fully developed modeling and validated by Samad's analytical solution and Chang's asymptotic results. After the code validation, numerical simulation is extended to high Hartmann number for MHD circular pipe flows with conducting walls, and numerical results such as velocity distribution and MHD pressure gradient are obtained. Typical M-type velocity is observed but there is not such a big velocity jet as that of MHD rectangular duct flows even under the conditions of high Hartmann numbers and big wall conductance ratio. The over speed region in Robert layers becomes smaller when Hartmann numbers increase. When Hartmann number is fixed and wall conductance ratios change, the dimensionless velocity is through one point which is in agreement with Samad's results, the locus of maximum value of velocity jet is same and effects of wall conductance ratio only on the maximum value of velocity jet. In case of Robert walls are treated as insulating and Hartmann walls as conducting for circular pipe MHD flows, there is big velocity jet like as MHD rectangular duct flows of Hunt's case 2

  11. Observation of the adsorption and desorption of vibrationally excited molecules on a metal surface

    Science.gov (United States)

    Shirhatti, Pranav R.; Rahinov, Igor; Golibrzuch, Kai; Werdecker, Jörn; Geweke, Jan; Altschäffel, Jan; Kumar, Sumit; Auerbach, Daniel J.; Bartels, Christof; Wodtke, Alec M.

    2018-06-01

    The most common mechanism of catalytic surface chemistry is that of Langmuir and Hinshelwood (LH). In the LH mechanism, reactants adsorb, become thermalized with the surface, and subsequently react. The measured vibrational (relaxation) lifetimes of molecules adsorbed at metal surfaces are in the range of a few picoseconds. As a consequence, vibrational promotion of LH chemistry is rarely observed, with the exception of LH reactions occurring via a molecular physisorbed intermediate. Here, we directly detect adsorption and subsequent desorption of vibrationally excited CO molecules from a Au(111) surface. Our results show that CO (v = 1) survives on a Au(111) surface for 1 × 10-10 s. Such long vibrational lifetimes for adsorbates on metal surfaces are unexpected and pose an interesting challenge to the current understanding of vibrational energy dissipation on metal surfaces. They also suggest that vibrational promotion of surface chemistry might be more common than is generally believed.

  12. Vibrational circular dichroism from ab initio molecular dynamics and nuclear velocity perturbation theory in the liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Scherrer, Arne [Martin-Luther-Universität Halle-Wittenberg, Institut für Chemie, von-Danckelmann-Platz 4, 06120 Halle (Germany); Département de Chimie, École Normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, PASTEUR, 24 rue Lhomond, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris (France); Vuilleumier, Rodolphe, E-mail: rodolphe.vuilleumier@ens.fr [Département de Chimie, École Normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, PASTEUR, 24 rue Lhomond, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005 Paris (France); Sebastiani, Daniel, E-mail: daniel.sebastiani@chemie.uni-halle.de [Martin-Luther-Universität Halle-Wittenberg, Institut für Chemie, von-Danckelmann-Platz 4, 06120 Halle (Germany)

    2016-08-28

    We report the first fully ab initio calculation of dynamical vibrational circular dichroism spectra in the liquid phase using nuclear velocity perturbation theory (NVPT) derived electronic currents. Our approach is rigorous and general and thus capable of treating weak interactions of chiral molecules as, e.g., chirality transfer from a chiral molecule to an achiral solvent. We use an implementation of the NVPT that is projected along the dynamics to obtain the current and magnetic dipole moments required for accurate intensities. The gauge problem in the liquid phase is resolved in a twofold approach. The electronic expectation values are evaluated in a distributed origin gauge, employing maximally localized Wannier orbitals. In a second step, the gauge invariant spectrum is obtained in terms of a scaled molecular moments, which allows to systematically include solvent effects while keeping a significant signal-to-noise ratio. We give a thorough analysis and discussion of this choice of gauge for the liquid phase. At low temperatures, we recover the established double harmonic approximation. The methodology is applied to chiral molecules ((S)-d{sub 2}-oxirane and (R)-propylene-oxide) in the gas phase and in solution. We find an excellent agreement with the theoretical and experimental references, including the emergence of signals due to chirality transfer from the solute to the (achiral) solvent.

  13. Normal and reversed supramolecular chirality of insulin fibrils probed by vibrational circular dichroism at the protofilament level of fibril structure.

    Science.gov (United States)

    Kurouski, Dmitry; Dukor, Rina K; Lu, Xuefang; Nafie, Laurence A; Lednev, Igor K

    2012-08-08

    Fibrils are β-sheet-rich aggregates that are generally composed of several protofibrils and may adopt variable morphologies, such as twisted ribbons or flat-like sheets. This polymorphism is observed for many different amyloid associated proteins and polypeptides. In a previous study we proposed the existence of another level of amyloid polymorphism, namely, that associated with fibril supramolecular chirality. Two chiral polymorphs of insulin, which can be controllably grown by means of small pH variations, exhibit opposite signs of vibrational circular dichroism (VCD) spectra. Herein, using atomic force microscopy (AFM) and scanning electron microscopy (SEM), we demonstrate that indeed VCD supramolecular chirality is correlated not only by the apparent fibril handedness but also by the sense of supramolecular chirality from a deeper level of chiral organization at the protofilament level of fibril structure. Our microscopic examination indicates that normal VCD fibrils have a left-handed twist, whereas reversed VCD fibrils are flat-like aggregates with no obvious helical twist as imaged by atomic force microscopy or scanning electron microscopy. A scheme is proposed consistent with observed data that features a dynamic equilibrium controlled by pH at the protofilament level between left- and right-twist fibril structures with distinctly different aggregation pathways for left- and right-twisted protofilaments. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  14. The amide III vibrational circular dichroism band as a probe to detect conformational preferences of alanine dipeptide in water.

    Science.gov (United States)

    Mirtič, Andreja; Merzel, Franci; Grdadolnik, Jože

    2014-07-01

    The conformational preferences of blocked alanine dipeptide (ADP), Ac-Ala-NHMe, in aqueous solution were studied using vibrational circular dichroism (VCD) together with density functional theory (DFT) calculations. DFT calculations of three most representative conformations of ADP surrounded by six explicit water molecules immersed in a dielectric continuum have proven high sensitivity of amide III VCD band shape that is characteristic for each conformation of the peptide backbone. The polyproline II (PII ) and αR conformation of ADP are associated with a positive VCD band while β conformation has a negative VCD band in amide III region. Knowing this spectral characteristic of each conformation allows us to assign the experimental amide III VCD spectrum of ADP. Moreover, the amide III region of the VCD spectrum was used to determine the relative populations of conformations of ADP in water. Based on the interpretation of the amide III region of VCD spectrum we have shown that dominant conformation of ADP in water is PII which is stabilized by hydrogen bonded water molecules between CO and NH groups on the peptide backbone. Copyright © 2014 Wiley Periodicals, Inc.

  15. Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems

    Science.gov (United States)

    Fakkaew, Wichaphon; Cole, Matthew O. T.

    2018-06-01

    This paper investigates the vibration arising in a thin-walled cylindrical rotor subject to small non-circularity and coupled to discrete space-fixed radial bearing supports. A Fourier series description of rotor non-circularity is incorporated within a mathematical model for vibration of a rotating annulus. This model predicts the multi-harmonic excitation of the rotor wall due to bearing interactions. For each non-circularity harmonic there is a set of distinct critical speeds at which resonance can potentially arise due to flexural mode excitation within the rotor wall. It is shown that whether each potential resonance occurs depends on the multiplicity and symmetry of the bearing supports. Also, a sufficient number of evenly spaced identical supports will eliminate low order resonances. The considered problem is pertinent to the design and operation of thin-walled rotors with active magnetic bearing (AMB) supports, for which small clearances exist between the rotor and bearing and so vibration excitation must be limited to avoid contacts. With this motivation, the mathematical model is further developed for the case of a distributed array of electromagnetic actuators controlled by feedback of measured rotor wall displacements. A case study involving an experimental system with short cylindrical rotor and a single radial AMB support is presented. The results show that flexural mode resonance is largely avoided for the considered design topology. Moreover, numerical predictions based on measured non-circularity show good agreement with measurements of rotor wall vibration, thereby confirming the validity and utility of the theoretical model.

  16. Tight beta-turns in peptides. DFT-based study of infrared absorption and vibrational circular dichroism for various conformers including solvent effects

    Czech Academy of Sciences Publication Activity Database

    Kim, J.; Kapitán, Josef; Lakhani, A.; Bouř, Petr; Keiderling, T. A.

    2008-01-01

    Roč. 119, 1/3 (2008), s. 81-97 ISSN 1432-881X R&D Projects: GA ČR GA203/06/0420 Grant - others:NSF(US) CHE03-16014 Institutional research plan: CEZ:AV0Z40550506 Keywords : peptide beta -turn * density functional theory * infrared absorption * vibrational circular dichroism Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.370, year: 2008

  17. Laminar natural convection heat transfer from a horizontal circular cylinder to liquid metals

    International Nuclear Information System (INIS)

    Sugiyama, K.; Ma, Y.; Ishiguro, R.

    1991-01-01

    The objective of the present study is to clarify the heat transfer characteristic of natural convection around a horizontal circular cylinder immersed in liquid metals. Experimental work concerning liquid metals sometimes involves such a degree of error that is impossible to understand the observed characteristics in measurement. Numerical analysis is a powerful means to overcome this experimental disadvantage. In the present paper the authors first show that the Boussinesq approximation is more applicable heat transfer rates, even for a cylinder with a relatively large temperature difference (>100K) between the heat transfer surface and fluid. It is found from a comparison of the present results with previous work that the correlation equations that have already been proposed predict values lower than the present ones

  18. Vibration-accelerated activation of flow units in a Pd-based bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ning, E-mail: hslining@mail.hust.edu.cn [School of Materials Science and Engineering, and State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Liu, Ze [Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan 430072 (China); Wang, Xinyun [School of Materials Science and Engineering, and State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Meng [Institute of Advanced Wear & Corrosion Resistant and Functional Materials, Jinan University, Guangzhou 510632 (China)

    2017-04-24

    Controlled activation of flow units and in-situ characterization of mechanical properties in metallic glasses are facing challenges thus far. Here, vibrational loading is introduced through nanoscale dynamic mechanical analysis technique to probe vibration-accelerated atomic level flow that plays a crucial role in the mechanical behavior of metallic glasses. The intriguing finding is that high vibrational frequency induces deep indentation depth, prominent pop-in events on load–depth curves and low storage modulus, exhibiting a vibration-facilitated activation of flow units in Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} metallic glass. Theoretical analysis revealed that vibration-moderated activation time-scale accelerate the activation of flow units and responsible for the above scenario.

  19. Electronic thermal conductivity of 2-dimensional circular-pore metallic nanoporous materials

    International Nuclear Information System (INIS)

    Huang, Cong-Liang; Lin, Zi-Zhen; Luo, Dan-Chen; Huang, Zun

    2016-01-01

    The electronic thermal conductivity (ETC) of 2-dimensional circular-pore metallic nanoporous material (MNM) was studied here for its possible applications in thermal cloaks. A simulation method based on the free-electron-gas model was applied here without considering the quantum effects. For the MNM with circular nanopores, there is an appropriate nanopore size for thermal conductivity tuning, while a linear relationship exists for this size between the ETC and the porosity. The appropriate nanopore diameter size will be about one times that of the electron mean free path. The ETC difference along different directions would be less than 10%, which is valuable when estimating possible errors, because the nanoscale-material direction could not be controlled during its application. Like nanoparticles, the ETC increases with increasing pore size (diameter for nanoparticles) while the porosity was fixed, until the pore size reaches about four times that of electron mean free path, at which point the ETC plateaus. The specular coefficient on the surface will significantly impact the ETC, especially for a high-porosity MNM. The ETC can be decreased by 30% with a tuning specular coefficient. - Highlights: • For metallic nanoporous materials, there is an appropriate pore size for thermal conductivity tuning. • ETC increases with increasing pore size until pore size reaches about four times EMFP. • The ETC difference between different directions will be less than 10%. • The ETC can be decreased by 30% with tuning specular coefficient.

  20. Vibration analysis of orthotropic circular and elliptical nano-plates embedded in elastic medium based on nonlocal Mindlin plate theory and using Galerkin method

    International Nuclear Information System (INIS)

    Anjomshoa, Amin; Tahani, Masoud

    2016-01-01

    In the present study a continuum model based on the nonlocal elasticity theory is developed for free vibration analysis of embedded ortho tropic thick circular and elliptical nano-plates rested on an elastic foundation. The elastic foundation is considered to behave like a Pasternak type of foundations. Governing equations for vibrating nano-plate are derived according to the Mindlin plate theory in which the effects of shear deformations of nano-plate are also included. The Galerkin method is then employed to obtain the size dependent natural frequencies of nano-plate. The solution procedure considers the entire nano-plate as a single super-continuum element. Effect of nonlocal parameter, lengths of nano-plate, aspect ratio, mode number, material properties, thickness and foundation on circular frequencies are investigated. It is seen that the nonlocal frequencies of the nano-plate are smaller in comparison to those from the classical theory and this is more pronounced for small lengths and higher vibration modes. It is also found that as the aspect ratio increases or the nanoplate becomes more elliptical, the small scale effect on natural frequencies increases. Further, it is observed that the elastic foundation decreases the influence of nonlocal parameter on the results. Since the effect of shear deformations plays an important role in vibration analysis and design of nano-plates, by predicting smaller values for fundamental frequencies, the study of these nano-structures using thick plate theories such as Mindlin plate theory is essential.

  1. INDUCTION HEATING OF NON-MAGNETIC SHEET METALS IN THE FIELD OF A FLAT CIRCULAR MULTITURN SOLENOID

    Directory of Open Access Journals (Sweden)

    Y. Batygin

    2016-06-01

    Full Text Available The theoretical analysis of electromagnetic processes in the system for induction heating presented by a flat circular multiturn solenoid positioned above a plane of thin sheet non-magnetic metal has been conducted. The calculated dependences for the current induced in a metal sheet blank and ratio of transformation determined have been obtained. The maximal value of the transformation ratio with regard to spreading the eddy-currents over the whole area of the sheet metal has been determined.

  2. Assessment of the vibration on the foam legged and sheet metal-legged passenger seat

    Directory of Open Access Journals (Sweden)

    L. Dahil

    2015-10-01

    Full Text Available In this study, it was aim ed to decrease the vibration reaching to passenger from the legs of vehicle seats. In order to determine the levels of vibrations reaching at passengers, a test pad placed under the passenger seat was used, and HVM100 device was used for digitizing the information obtained. By transferring the vibration data to system by using HVM100 device, the acceleration graphics were prepared with Blaze software. As a result, it was determined that the acceleration values of seat legs made of foam material were lower than that of seat legs made of 2 mm thick sheet metal, so they damped the vibration better.

  3. Angular-dependent photodetection enhancement by a metallic circular disk optical antenna

    Directory of Open Access Journals (Sweden)

    Thitikorn Kemsri

    2017-02-01

    Full Text Available In this paper, we analyze the plasmonic resonance excited by linearly polarized longwave infrared (LWIR plane waves in a metallic circular disk optical antenna (MCDA. The surface current distributions are simulated at different wavelengths, incident angles, and polarizations. The excited surface plasmonic resonance waves (SPRs are different from the Bessel-type of SPR modes and closely resemble those in a monopole antenna. An MCDA coupled LWIR quantum dot infrared photodetector (QDIP was fabricated and measured at different LWIR plane wave wavelengths and incident angles. A linear correlation between the enhancement ratio and the integrated square of the current is obtained, indicating the monopole antenna effect is a dominating factor for the plasmonic enhancement.

  4. Effect of length to thickness ratio on free vibration analysis of thick fiber reinforced plastic skew cross-ply laminate with circular cutout

    Science.gov (United States)

    Srividya, K.; Reddy, Ch. Kishore; Sumanth, Ch. Mohan; Krishnaiah, P. Gopala; Kishan, V. Mallikharjuna

    2018-04-01

    The present investigation deals with the free vibration analysis of a thick four-layered symmetric cross-ply skew laminated composite plate with a circular cutout. Three dimensional finite element models (FEM) which use the elasticity theory for the determination of stiffness matrices are modeled in ANSYS software to evaluate first five natural frequencies of the laminate. The variations of the first five natural frequencies with respect to length to thickness ratio (S) for different diameter to length ratios (d/l) are presented. It is observed that, the natural frequencies decreases with increase of thickness ratio(S).

  5. Vibrational circular dichroism of a 2,5-diketopiperazine (DKP) peptide: Evidence for dimer formation in cyclo LL or LD diphenylalanine in the solid state.

    Science.gov (United States)

    Pérez-Mellor, Ariel; Zehnacker, Anne

    2017-02-01

    The diastereomer diketopiperazine (DKP) peptides built on phenylalanine, namely, cyclo diphenylalanine LPhe-LPhe and LPhe-DPhe, were studied in the solid phase by vibrational circular dichroism (VCD) coupled to quantum chemical calculations. The unit structure of cyclo LPhe-LPhe in KBr pellets is a dimer bridged by two strong NH…O hydrogen bonds. The intense bisignate signature in the CO stretch region is interpreted in terms of two contributions arising from the free COs of the dimer and the antisymmetrical combination of the bound COs. In contrast, cyclo LPhe-DPhe shows no VCD signal in relation to its symmetric nature. © 2017 Wiley Periodicals, Inc.

  6. Lanthanide tris(β-diketonates) as useful probes for chirality determination of biological amino alcohols in vibrational circular dichroism: ligand to ligand chirality transfer in lanthanide coordination sphere.

    Science.gov (United States)

    Miyake, Hiroyuki; Terada, Keiko; Tsukube, Hiroshi

    2014-06-01

    A series of lanthanide tris(β-diketonates) functioned as useful chirality probes in the vibrational circular dichroism (VCD) characterization of biological amino alcohols. Various chiral amino alcohols induced intense VCD signals upon ternary complexation with racemic lanthanide tris(β-diketonates). The VCD signals observed around 1500 cm(-1) (β-diketonate IR absorption region) correlated well with the stereochemistry and enantiomeric purity of the targeted amino alcohol, while the corresponding monoalcohol, monoamine, and diol substrates induced very weak VCD signals. The high-coordination number and dynamic property of the lanthanide complex offer an effective chirality VCD probing of biological substrates. © 2014 Wiley Periodicals, Inc.

  7. The Role of Laser Additive Manufacturing Methods of Metals in Repair, Refurbishment and Remanufacturing - Enabling Circular Economy

    Science.gov (United States)

    Leino, Maija; Pekkarinen, Joonas; Soukka, Risto

    Circular economy is an economy model where products, components, and materials are aimed to be kept at their highest utility and value at all times. Repair, refurbishment and remanufacturing processes are procedures aiming at returning the value of the product during its life cycle. Additive manufacturing (AM) is expected to be an enabling technology in circular economy based business models. One of AM process that enables repair, refurbishment and remanufacturing is Directed Energy Deposition. Respectively Powder Bed Fusion enables manufacturing of replacement components on demand. The aim of this study is to identify the current research findings and state of art of utilizing AM in repair, refurbishment and remanufacturing processes of metallic products. The focus is in identifying possibilities of AM in promotion of circular economy and expected environmental benefits based on the found literature. Results of the study indicate significant potential in utilizing AM in repair, refurbishment and remanufacturing activities.

  8. Circularly polarized triple band glass shaped monopole patch antenna with metallic reflector for bluetooth & wireless applications

    Science.gov (United States)

    Jangid, K. G.; Choudhary, N.; Jain, P.; Sharma, B. R.; Saini, J. S.; Kulhar, V. S.; Bhatnagar, D.

    2016-03-01

    This paper presents the design and performance of strip line fed glass shaped monopole patch antenna having with overall size 30mm × 30 mm × 1.59 mm. In the patch; an eight shaped slot and in the ground plane an eight shaped ring are introduced. A metallic ground plane is also introduced at appropriate location beneath the ground plane. The proposed antenna is simulated by applying CST Microwave Studio simulator. Antenna provides circularly polarized radiations, triple broad impedance bandwidth of 203MHz (2.306GHz to 2.510GHz), 42MHz (2.685GHz to 2.757GHz) & GHz (3.63 GHz to 6.05 GHz), high flat gain (close to 5dBi) and good radiation properties in the desired frequency range. This antenna may be a very useful tool for 2.45GHz Bluetooth communication band as well as for 2.4GHz/5.2 GHz /5.8 GHz WLAN bands & 3.7GHz/5.5 GHz Wi-Max bands.

  9. Circularly polarized triple band glass shaped monopole patch antenna with metallic reflector for bluetooth & wireless applications

    Energy Technology Data Exchange (ETDEWEB)

    Jangid, K. G.; Kulhar, V. S. [Department of Physics, Manipal University Jaipur, Jaipur-303007 (India); Choudhary, N.; Jain, P.; Sharma, B. R.; Saini, J. S.; Bhatnagar, D., E-mail: dbhatnagar-2000@rediffmail.com [Microwave Lab, Department of Physics, University of Rajasthan, Jaipur-302004 (India)

    2016-03-09

    This paper presents the design and performance of strip line fed glass shaped monopole patch antenna having with overall size 30mm × 30 mm × 1.59 mm. In the patch; an eight shaped slot and in the ground plane an eight shaped ring are introduced. A metallic ground plane is also introduced at appropriate location beneath the ground plane. The proposed antenna is simulated by applying CST Microwave Studio simulator. Antenna provides circularly polarized radiations, triple broad impedance bandwidth of 203MHz (2.306GHz to 2.510GHz), 42MHz (2.685GHz to 2.757GHz) & GHz (3.63 GHz to 6.05 GHz), high flat gain (close to 5dBi) and good radiation properties in the desired frequency range. This antenna may be a very useful tool for 2.45GHz Bluetooth communication band as well as for 2.4GHz/5.2 GHz /5.8 GHz WLAN bands & 3.7GHz/5.5 GHz Wi-Max bands.

  10. MR imaging in the presence of small circular metallic implants. Assessment of thermal injuries

    International Nuclear Information System (INIS)

    Manner, I.; Alanen, A.; Komu, M.; Savunen, T.; Kantonen, I.; Ekfors, T.

    1996-01-01

    Purpose: The thermal effects of MR imaging in the presence of circular nonferromagnetic metallic implants were studied in 6 rabbits. Material and Methods: A sternotomy was performed and fixed with stainless steel wires, and small titanium rings (diameter 3 mm) were placed on the surface of the ascending aorta and subcutaneous tissue of the thigh. Four of the rabbits were exposed to an imaging procedure with a 1.5 T scanner applying a T1-weighted spin-echo sequence and a gradient echo sequence. Two of the animals served as unexposed controls. Thirty-six hours after the exposure, tissues adjacent to the implants were examined histologically and compared with corresponding samples of the control animals. Results: In the area of the titanium rings, histologic analysis revealed slight inflammatory changes apparently caused by the operation. No evidence of thermal injury was found, suggesting that the presence of the rings does not contraindicate MR examinations. Necrosis was noted in all of the sternal specimens. This was probably post-operative, but it impaired the assessment of thermal injury in this area. (orig.)

  11. Determination of the absolute configurations of natural products via density functional theory calculations of optical rotation, electronic circular dichroism, and vibrational circular dichroism: the cytotoxic sesquiterpene natural products quadrone, suberosenone, suberosanone, and suberosenol A acetate.

    Science.gov (United States)

    Stephens, P J; McCann, D M; Devlin, F J; Smith, A B

    2006-07-01

    The determination of the absolute configurations (ACs) of chiral molecules using the chiroptical techniques of optical rotation (OR), electronic circular dichroism (ECD), and vibrational circular dichroism (VCD) has been revolutionized by the development of density functional theory (DFT) methods for the prediction of these properties. Here, we demonstrate the significance of these advances for the stereochemical characterization of natural products. Time-dependent DFT (TDDFT) calculations of the specific rotations, [alpha](D), of four cytotoxic natural products, quadrone (1), suberosenone (2), suberosanone (3), and suberosenol A acetate (4), are used to assign their ACs. TDDFT calculations of the ECD of 1 are used to assign its AC. The VCD spectrum of 1 is reported and also used, together with DFT calculations, to assign its AC. The ACs of 1 derived from its [alpha](D), ECD, and VCD are identical and in agreement with the AC previously determined via total synthesis. The previously undetermined ACs of 2-4, derived from their [alpha](D) values, have absolute configurations of their tricyclic cores identical to that of 1. Further studies of the ACs of these molecules using ECD and, especially, VCD are recommended to establish more definitively this finding. Our studies of the OR, ECD, and VCD of quadrone are the first to utilize DFT calculations of all three properties for the determination of the AC of a chiral natural product molecule.

  12. Vortex-induced vibrations of circular cylinder in cross flow at supercritical Reynolds numbers; Chorinkai Reynolds su ryoiki ni okeru enchu no uzu reiki shindo

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, T.; Nakao, T.; Takahashi, M.; Hayashi, M.; Goto, N. [Hitachi, Ltd., Tokyo (Japan)

    1999-07-25

    Vortex-induced vibrations were measured for a circular cylinder subjected to a water cross flow at supercritical Reynolds numbers for a wide range of reduced velocities. Turbulence intensities were changed from 1% to 13% in order to investigate the effect of the Strouhal number on the region of synchronization by symmetrical and Karman vortex shedding. The reduced damping of the test cylinder was about 0.1 in water. The surface roughness of the cylinder was a mirror-polished surface. Strouhal number decreased from about 0.48 to 0.29 with increasing turbulence intensity. Synchronized vibrations were observed even at supercritical Reynolds numbers where fluctuating fluid force was small. Reduced velocities at which drag and lift direction lock-in by Karman vortex shedding were initiated decreased with increasing Strouhal number. When Strouhal number was about 0.29, the self-excited vibration in drag direction by symmetrical vortex shedding began at which the frequency ratio of Karman vortex shedding frequency to the natural frequency of cylinder was 0.32. (author)

  13. Structural coloration of metallic surfaces with micro/nano-structures induced by elliptical vibration texturing

    Science.gov (United States)

    Yang, Yang; Pan, Yayue; Guo, Ping

    2017-04-01

    Creating orderly periodic micro/nano-structures on metallic surfaces, or structural coloration, for control of surface apparent color and optical reflectivity has been an exciting research topic over the years. The direct applications of structural coloration include color marking, display devices, and invisibility cloak. This paper presents an efficient method to colorize metallic surfaces with periodic micro/nano-gratings using elliptical vibration texturing. When the tool vibration is coupled with a constant cutting velocity, controlled periodic ripples can be generated due to the overlapping tool trajectory. These periodic ripples with a wavelength near visible spectrum can act as micro-gratings to introduce iridescent colors. The proposed technique also provides a flexible method for color marking of metallic surfaces with arbitrary patterns and images by precise control of the spacing distance and orientation of induced micro/nano-ripples. Theoretical analysis and experimental results are given to demonstrate structural coloration of metals by a direct mechanical machining technique.

  14. Lattice vibrational properties of transition metal carbides (TiC, ZrC

    Indian Academy of Sciences (India)

    Lattice vibrational properties of transition metal carbides (TiC, ZrC and HfC) have been presented by including the effects of free-carrier doping and three-body interactions in the rigid shell model. The short-range overlap repulsion is operative up to the second neighbour ions. An excellent agreement has been obtained ...

  15. Substrate Vibrations as Promoters of Chemical Reactivity on Metal Surfaces.

    Science.gov (United States)

    Campbell, Victoria L; Chen, Nan; Guo, Han; Jackson, Bret; Utz, Arthur L

    2015-12-17

    Studies exploring how vibrational energy (Evib) promotes chemical reactivity most often focus on molecular reagents, leaving the role of substrate atom motion in heterogeneous interfacial chemistry underexplored. This combined theoretical and experimental study of methane dissociation on Ni(111) shows that lattice atom motion modulates the reaction barrier height during each surface atom's vibrational period, which leads to a strong variation in the reaction probability (S0) with surface temperature (Tsurf). State-resolved beam-surface scattering studies at Tsurf = 90 K show a sharp threshold in S0 at translational energy (Etrans) = 42 kJ/mol. When Etrans decreases from 42 kJ/mol to 34 kJ/mol, S0 decreases 1000-fold at Tsurf = 90 K, but only 2-fold at Tsurf = 475 K. Results highlight the mechanism for this effect, provide benchmarks for DFT calculations, and suggest the potential importance of surface atom induced barrier height modulation in heterogeneously catalyzed reactions, particularly on structurally labile nanoscale particles and defect sites.

  16. A rapid alternative to X-ray crystallography for chiral determination: case studies of vibrational circular dichroism (VCD) to advance drug discovery projects.

    Science.gov (United States)

    Wesolowski, Steven S; Pivonka, Don E

    2013-07-15

    The absolute stereochemistry of chiral drugs is usually established via X-ray crystallography. However, vibrational circular dichroism (VCD) spectroscopy coupled with quantum mechanics simulations offers a rapid alternative to crystallography and is readily applied to both crystalline and non-crystalline samples. VCD is an effective complement to X-ray analysis of drug candidates, and it can be used as a high-throughput means of assessing absolute stereochemistry at all phases of the discovery process (hundreds of assignments per year). The practical implementation (or fee-for-service outsourcing) of VCD and selected case studies are illustrated with an emphasis on providing utility and impact to pharmaceutical discovery programs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Asymmetric free vibrations of laminated annular cross-ply circular plates including the effects of shear deformation and rotary inertia. Spline method

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, K.K.; Kim, Kyung Su; Lee, Jang Hyun [Inha Univ., Incheon (Korea). Dept. of Naval Architecture and Ocean Engineering

    2009-12-15

    Asymmetric free vibrations of annular cross-ply circular plates are studied using spline function approximation. The governing equations are formulated including the effects of shear deformation and rotary inertia. Assumptions are made to study the cross-ply layered plates. A system of coupled differential equations are obtained in terms of displacement functions and rotational functions. These functions are approximated using Bickley- type spline functions of suitable order. Then the system is converted into the eigenvalue problem by applying the point collocation technique and suitable boundary conditions. Parametric studies have been made to investigate the effect of transverse shear deformation and rotary inertia on frequency parameter with respect to the circumferential node number, radii ratio and thickness to radius ratio for both symmetric and anti-symmetric cross-ply plates using various types of material properties. (orig.)

  18. Influence of contact conditions on vibration induced wear of metals

    International Nuclear Information System (INIS)

    Hofmann, P.J.; Schettler, T.; Wieling, N.; Steininger, D.A.

    1990-01-01

    Unfavourable design characteristics of nuclear power plant steam generators and heat exchangers in general may result in vibration induced tube wear. A systematic investigation was performed on the contact conditions which may appear between heat exchanger tubes and tube support structure and the influence of different parameters e.g., normal contact force, on the resulting steady state wear rates. It is concluded that not only are contact forces and sliding distances important in the wear process but also the type of relative motion has a decisive influence on the resulting wear rates. For a certain 'work rate', the wear rate caused by repeated impact motions between tube and tube support structure may be an order of magnitude higher than that caused by only sliding motion. This is the result of different operating wear mechanisms which are discussed in this paper. (orig.)

  19. Accelerated lifetime test of vibration isolator made of Metal Rubber material

    Science.gov (United States)

    Ao, Hongrui; Ma, Yong; Wang, Xianbiao; Chen, Jianye; Jiang, Hongyuan

    2017-01-01

    The Metal Rubber material (MR) is a kind of material with nonlinear damping characteristics for its application in the field of aerospace, petrochemical industry and so on. The study on the lifetime of MR material is impendent to its application in engineering. Based on the dynamic characteristic of MR, the accelerated lifetime experiments of vibration isolators made of MR working under random vibration load were conducted. The effects of structural parameters of MR components on the lifetime of isolators were studied and modelled with the fitting curves of degradation data. The lifetime prediction methods were proposed based on the models.

  20. Vibrational properties of vacancy in bcc transition metals using ...

    Indian Academy of Sciences (India)

    The calculated results of the formation entropy of the vacancy compared well with other available ... for Fe, Mo and W transition metals employing a third-neighbour model. ... For the atomic electron density we have chosen a power law: f (r) = fe.

  1. The Role of Lattice Vibrations in Adatom Diffusion at Metal Stepped Surfaces

    International Nuclear Information System (INIS)

    Durakanoglu, S.

    2004-01-01

    Diffusion of a single atom on metal surfaces remains a subject of continuing interest in the surface science community because of the important role it plays in several technologically important phenomena such as thin-film and eptaxial growth, catalysis and chemical reactions. Except for a few studies, most of theoretical works, ranging from molecular dynamic simulations to first principle electronic structure calculations, are devoted to determination of the characteristics of the diffusion processes and the energy barriers, neglecting the contribution of lattice vibrations in adatom diffusion. However, in a series of theoretical works on self-diffusion on the flat surfaces of Cu(100), Ag(100) and Ni(100), Ulrike et al.[1-3], showed that the vibrational contributions are important and should be included in any complete description of the temperature dependence of the diffusion coefficient. In this work, it is our aim to examine the role of lattice vibrations in adatom diffusion at stepped surfaces of Cu(100) and Ni(100) within the framework of transition state theory. Ehrlich-Shwoebel energy barriers for an adatom diffusing over a step-edge are calculated through the inclusion of vibrational internal energy. Local vibrational density of states, main ingredient to the vibrational thermodynamic functions, are calculated in the harmonic approximation, using real space Green's function method with the force constants derived from interaction potentials based on the embedded atom method. We emphasize the sensitivity of the local vibrational density of states to the local atomic environment. We, furthermore, discuss the contribution of thermodynamic functions calculated from local vibrational density of states to the prefactors in diffusion coefficient

  2. Vibrational spectra of double rare earth alkaline metal metaphosphates

    International Nuclear Information System (INIS)

    Madij, V.A.; Krasilov, Yu.I.; Kizel', V.A.; Denisov, Yu.V.; Chudinova, N.N.; Vinogradova, N.V.

    1978-01-01

    Joint analysis of the Raman and infrared absorption spectra, as well as X-ray structural data for binary metaphosphates, suggest a cyclic structure of the anion in RbEu(PO 3 ) 4 and a chain structure of the anions in HEu(PO 3 ) 4 and LiEu(PO 3 ) 4 . Spectroscopic criteria are proposed for distinguishing between cyclic and chain structures in binary metaphosphates of rare earth elements and alkali metals

  3. Flow measurement and thrust estimation of a vibrating ionic polymer metal composite

    International Nuclear Information System (INIS)

    Chae, Woojin; Cha, Youngsu; Peterson, Sean D; Porfiri, Maurizio

    2015-01-01

    Ionic polymer metal composites (IPMCs) are an emerging class of soft active materials that are finding growing application as underwater propulsors for miniature biomimetic swimmers. Understanding the hydrodynamics generated by an IPMC vibrating under water is central to the design of such biomimetic swimmers. In this paper, we propose the use of time-resolved particle image velocimetry to detail the fluid kinematics and kinetics in the vicinity of an IPMC vibrating along its fundamental structural mode. The reconstructed pressure field is ultimately used to estimate the thrust produced by the IPMC. The vibration frequency is systematically varied to elucidate the role of the Reynolds number on the flow physics and the thrust production. Experimental results indicate the formation and shedding of vortical structures from the IPMC tip during its vibration. Vorticity shedding is sustained by the pressure gradients along each side of the IPMC, which are most severe in the vicinity of the tip. The mean thrust is found to robustly increase with the Reynolds number, closely following a power law that has been derived from direct three-dimensional numerical simulations. A reduced order distributed model is proposed to describe IPMC underwater vibration and estimate thrust production, offering insight into the physics of underwater propulsion and aiding in the design of IPMC-based propulsors. (paper)

  4. Bonding and vibrational dynamics of a large π-conjugated molecule on a metal surface

    International Nuclear Information System (INIS)

    Temirov, R; Soubatch, S; Lassise, A; Tautz, F S

    2008-01-01

    The interplay between the substrate bonding of a large π-conjugated semiconductor molecule and the dynamical properties of the metal-organic interface is studied, employing the prototypical PTCDA/Ag(111) monolayer as an example. Both the coupling of molecular vibrations to the electron-hole-pair continuum of the metal surface and the inelastic scattering of tunnelling electrons by the molecular vibrations on their passage through the molecule are considered. The results of both types of experiment are consistent with the findings of measurements which probe the geometric and electronic structure of the adsorbate-substrate complex directly; generally speaking, they can be understood in the framework of standard theories for the electron-vibron coupling. While the experiments reported here in fact provide additional qualitative insights into the substrate bonding of our π-conjugated model molecule, their detailed quantitative understanding would require a full calculation of the dynamical interface properties, which is currently not available

  5. Dispersion relation and electron acceleration in the combined circular and elliptical metallic-dielectric waveguide filled by plasma

    Science.gov (United States)

    Abdoli-Arani, A.; Montazeri, M. M.

    2018-04-01

    Two special types of metallic waveguide having dielectric cladding and plasma core including the combined circular and elliptical structure are studied. Longitudinal and transverse field components in the different regions are obtained. Applying the boundary conditions, dispersion relations of the electromagnetic waves in the structures are obtained and then plotted. The acceleration of an injected external relativistic electron in the considered waveguides is studied. The obtained differential equations related to electron motion are solved by the fourth-order Runge-Kutta method. Numerical computations are made, and the results are graphically presented.

  6. A nonlinear auxetic structural vibration damper with metal rubber particles

    International Nuclear Information System (INIS)

    Ma, Yanhong; Zhang, Dayi; Zhu, Bin; Chen, Lulu; Hong, Jie; Scarpa, Fabrizio

    2013-01-01

    The work describes the mechanical performance of a metal rubber particles (MRP) damper design based on an auxetic (negative Poisson’s ratio) cellular configuration. The auxetic damper configuration is constituted by an anti-tetrachiral honeycomb, where the cylinders are filled with the MRP material. The MRP samples have been subjected to quasi-static loading to measure the stiffness and loss factor from the static hysteresis curve. A parametric experimental analysis has been carried out to investigate the effect of relative density and filling percentage on the static performance of the MRP, and to identify design guidelines for best use of MRP devices. An experimental assessment of the integrated auxetic-MRP damper concept has been provided through static and dynamic force response techniques. (paper)

  7. Dual-band linearly and circularly polarized microstrip patch antennas with meandering slot and metallic vias

    DEFF Research Database (Denmark)

    Zhang, Jin; Lin, Xianqi; Yu, Jiawei

    2018-01-01

    performances. The characteristics are analyzed in detail where we find that the existence of the vias also improves the impedance matching. Four samples are designed, where dual-band with both linear polarization, dual-band with circular- and linear-polarization, and single band with linear polarization...

  8. Multipole induced splitting of metal-cage vibrations in crystalline endohedral D2d-M2@C84 dimetallofullerenes.

    Science.gov (United States)

    Krause, M; Popov, V N; Inakuma, M; Tagmatarchis, N; Shinohara, H; Georgi, P; Dunsch, L; Kuzmany, H

    2004-01-22

    Metal-carbon cage vibrations of crystalline endohedral D2d-M2@C84 (M=Sc,Y,Dy) dimetallofullerenes were analyzed by temperature dependent Raman scattering and a dynamical force field model. Three groups of metal-carbon cage modes were found at energies of 35-200 cm(-1) and assigned to metal-cage stretching and deformation vibrations. They exhibit a textbook example for the splitting of molecular vibrations in a crystal field. Induced dipole-dipole and quadrupole-quadrupole interactions account quantitatively for the observed mode splitting. Based on the metal-cage vibrational structure it is demonstrated that D2d-Y2@C84 dimetallofullerene retains a monoclinic crystal structure up to 550 K and undergoes a transition from a disordered to an ordered orientational state at a temperature of approximately 150 K.

  9. Theory for added mass of a vibrating circular rod in a two-phase air-water fluid

    International Nuclear Information System (INIS)

    Kohgo, Osamu; Hara, Fumio

    1985-01-01

    It has been well known that there are added mass and attenuation effect due to surrounding fluid in a structure vibrating in the fluid, and those are different according to the density and viscosity of the fluid and the form of the structure. In this study, in order to clarify added mass, the model of the vapor-liquid two-phase fluid with discontinuous density distribution was made. That is, bubbles were assumed to be a bubble column without bending stiffness and mass, and potential analysis was applied to a two-dimensional fluid field composed of a round section beam and the bubble column, thus their relative motion was hydrodynamically analyzed, and the theory for evaluating added mass was developed. The added mass experimentally determined from the response gain of a single round section cantilever when it was oscillated steadily, uniformly and at random in the vapor-liquid two-phase fluid being stationary as a whole and the theoretical result were examined by comparison, and equivalent bubble diameter was considered, thereafter, the validity of the model was examined. (Kako, I.)

  10. Vibrational dynamics of amorphous metals by inelastic neutron and raman scattering

    International Nuclear Information System (INIS)

    Lustig, N.E.

    1986-01-01

    Time-of-flight inelastic neutron scattering and Raman measurements were performed on amorphous (a-) metals. The neutron-weighted vibrational density of states, G(E), obtained for a-Fe 78 P 22 , a-Ni 82 B 18 and a-Ni 67 B 33 transition metal metalloid alloys (TM-m), indicated two major vibrational bands: a low frequency acoustic-like band and a high frequency optic-like band, derived from TM-TM and TM-m interactions, respectively. Similar neutron measurements were performed on the corresponding polycrystalline (c-) alloys, c-Fe 3 P and c-Ni 2 B. A comparison of the amorphous and crystalline densities of states indicates the elimination of sharp features and the addition of vibrational states at low and high frequencies upon amorphization. The experimental G(E) results for a-Fe 78 P 22 are in good agreement with the theoretically predicted spectrum. A comparison between the a-Ni 67 B 33 and the phenomenologically broadened c-Ni 2 B spectrum indicates a change in the short-range order. This finding is consistent with structural measurements on this alloy. Raman measurements were carried out using interference enhanced Raman spectroscopy (IERS) on thin film Ni-B alloys. The measured spectra provide information about the weighted phonon density of states, and is in good agreement with the neutron results

  11. Intra- versus Intermolecular Hydrogen Bonding: Solvent-Dependent Conformational Preferences of a Common Supramolecular Binding Motif from 1 H NMR and Vibrational Circular Dichroism Spectra.

    Science.gov (United States)

    Demarque, Daniel P; Merten, Christian

    2017-12-19

    When predicting binding properties of small molecules or larger supramolecular aggregates, intra- and intermolecular hydrogen bonds are often considered the most important factor. Spectroscopic techniques such as 1 H NMR spectroscopy are typically utilized to characterize such binding events, but interpretation is often qualitative and follows chemical intuition. In this study, we compare the effects of intramolecular hydrogen bonding and solvation on two chiral 2,6-pyridinediyl-dialkylamides. In comparison with 1 H NMR spectroscopy, vibrational circular dichroism (VCD) spectroscopy proved to be more sensitive to conformational changes. In fact, the change of the solvent from CDCl 3 to [D 6 ]DMSO generates mirror-image VCD spectra for the same enantiomer. Here, the common sense that the sterically less hindered group is more prone to solvation proved to be wrong according predicted VCD spectra, which clearly show that both asymmetric amide hydrogens are equally likely to be solvated, but never simultaneously. The competition between intra- and intermolecular hydrogen bonding and their importance for a correct prediction of spectral properties are discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Fluid dynamic forces acting on a circular tube bundle in cross flow. Proposals of generation condition of vortex-induced vibration and correlation equation of turbulence-induced exciting force

    International Nuclear Information System (INIS)

    Inada, Fumio; Yoneda, Kimitoshi; Yasuo, Akira; Nishihara, Takashi

    2000-01-01

    In the circular tube bundle immersed in the crossflow, the exciting force induced by the turbulence and periodically discharged vortices becomes large, and it is necessary to confirm a long-term integrity to the flow induced vibration. In this report, the local fluid exciting force and the correlation length in the direction of tube axis were measured. The exciting force acting on the first row was smaller than that inside the tube bundle, and the exciting force was almost saturated at the third row. As for vortex induced vibration, there could be an influence when a dimensionless frequency was 0.4 or less. When vortex induced vibration did not affect the vibration, a correlation composed of a correlation length and power spectrum density of the local fluid exciting force were proposed, with which we could estimate the amplitude of the vibration. A computer program to estimate the vibration amplitude and maximum stress was made using the flow velocity distribution and the mode of vibration. (author)

  13. Ecological and health risks assessment and spatial distribution of residual heavy metals in the soil of an e-waste circular economy park in Tianjin, China.

    Science.gov (United States)

    Han, Wei; Gao, Guanghai; Geng, Jinyao; Li, Yao; Wang, Yingying

    2018-04-01

    Ziya Circular Economy Park is the biggest e-waste recycle park in North China before 2011, its function was then transformed in response to regulations and rules. In this paper, investigation was conducted to research the residual concentrations of 14 analytes (12 heavy metals and 2 non-metals) in the surface soil of Ziya Circular Economy Park and surrounding area. Both ecological and health assessments were evaluated using GI (geo-accumulation index) and NPI (Nemerow pollution index), and associated health risk was assessed by using USEPA model. According to the ecological risk assessment, Cu, Sb, Cd, Zn and Co were seriously enriched in the soil of the studied area. The health risk assessment proposed by USEPA indicated no significant health risks to the population. Soil properties, such as pH and organic matter, were found to correlate with the enrichment of heavy metals. Arsenic concentrations in the soil were found positively correlated to dead bacteria concentrations. Spatial distribution of heavy metals revealed that Ziya Circular Economy Park was the dominant pollution source in the studied area. Findings in this study suggest that enough attention should be payed to the heavy metal pollution in Ziya Circular Economy Park. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Scrap metals' role in circular economy in Ghana, using Sunyani as a ...

    African Journals Online (AJOL)

    EJIRO

    quantity and economic value of scrap metals as essential part of resource ... Therefore, proper education, policy and regulatory measures are key recommendations to ... The methodology of this research includes the description of the.

  15. Administrative Circulars

    CERN Document Server

    Département des Ressources humaines

    2004-01-01

    Administrative Circular N° 2 (Rev. 2) - May 2004 Guidelines and procedures concerning recruitment and probation period of staff members This circular has been revised. It cancels and replaces Administrative Circular N° 2 (Rev. 1) - March 2000. Administrative Circular N° 9 (Rev. 3) - May 2004 Staff members contracts This circular has been revised. It cancels and replaces Administrative Circular N° 9 (Rev. 2) - March 2000. Administrative Circular N° 26 (Rev. 4) - May 2004 Procedure governing the career evolution of staff members This circular has also been revised. It Administrative Circulars Administrative Circular N° 26 (Rev. 3) - December 2001 and brings up to date the French version (Rev. 4) published on the HR Department Web site in January 2004. Operational Circular N° 7 - May 2004 Work from home This circular has been drawn up. Operational Circular N° 8 - May 2004 Dealing with alcohol-related problems...

  16. Analysis of Parameters Assessment on Laminated Rubber-Metal Spring for Structural Vibration

    International Nuclear Information System (INIS)

    Salim, M.A.; Putra, A.; Mansor, M.R.; Musthafah, M.T.; Akop, M.Z.; Abdullah, M.A.

    2016-01-01

    This paper presents the analysis of parameter assessment on laminated rubber-metal spring (LR-MS) for vibrating structure. Three parameters were selected for the assessment which are mass, Young's modulus and radius. Natural rubber materials has been used to develop the LR-MS model. Three analyses were later conducted based on the selected parameters to the LR-MS performance which are natural frequency, location of the internal resonance frequency and transmissibility of internal resonance. Results of the analysis performed were plotted in frequency domain function graph. Transmissibility of laminated rubber-metal spring (LR-MS) is changed by changing the value of the parameter. This occurrence was referred to the theory from open literature then final conclusion has been make which are these parameters have a potential to give an effects and trends for LR-MS transmissibility. (paper)

  17. Magnetic circular dichroism spectroscopy of weakly exchange coupled transition metal dimers: A model study

    DEFF Research Database (Denmark)

    Piligkos, S.; Slep, L.D.; Weyhermuller, T.

    2009-01-01

    bands of the minority spin Ni(II) ligand field bands were observed to change sign relative to the parent complex 2. This behavior has been analyzed. The present work hence provides a benchmark study for the application of MCD spectroscopy to weakly interacting transition metal dinners. (C) 2008 Elsevier...

  18. Nusselt number for turbulent flow of liquid metal in circular ducts

    International Nuclear Information System (INIS)

    Fernandez y Fernandez, E.; Carajilescov, P.

    1982-07-01

    The forced convection heat transfer in turbulent flow of liquid metals in ducts, is analyzed. An analogy between moment and heat at wall surface, is developed for determining one heat transfer coeficient in friction of friction coeficient. (E.G.) [pt

  19. Circular dichroism and Raman optical activity in antiferromagnetic transition metal fluorides

    International Nuclear Information System (INIS)

    Hoffman, K.R.; Lockwood, D.J.; Yen, W.M.

    2005-01-01

    The Raman optical activity (ROA) of magnons in rutile-structure antiferromagnetic FeF 2 (T N = 78 K) has been studied as a function of temperature and applied magnetic field. For exciting light incident along the c axis, ROA is observed for magnons but not for phonons. In zero field, a small splitting (0.09 cm -1 ) of the two acoustic-magnon branches is observed for the first time by inelastic light scattering. The splitting in applied magnetic field is found to reduce with increasing temperature in accordance with theory. No ROA was detected for two-magnon excitations. In optical absorption measurements performed over thirty years ago, a very small circular dichroism (CD) was observed in the magnon sidebands of other simple rutile antiferromagnetic fluorides (MnF 2 and CoF 2 ). The origin of this CD was not understood at the time. The Raman studies of the one-magnon Raman scattering in FeF 2 have demonstrated that in zero field the degeneracy of the antiferromagnetic magnon branches is lifted by a weak magnetic dipole-dipole interaction, as predicted by Pincus and Loudon and by White four decades ago. The source of the observed CD in the magnon sidebands can now be traced to this same magnetic-dipole induced splitting

  20. A novel smart rotor support with shape memory alloy metal rubber for high temperatures and variable amplitude vibrations

    International Nuclear Information System (INIS)

    Ma, Yanhong; Zhang, Qicheng; Zhang, Dayi; Hong, Jie; Scarpa, Fabrizio; Liu, Baolong

    2014-01-01

    The work describes the design, manufacturing and testing of a smart rotor support with shape memory alloy metal rubber (SMA-MR) elements, able to provide variable stiffness and damping characteristics with temperature, motion amplitude and excitation frequency. Differences in damping behavior and nonlinear stiffness between SMA-MR and more traditional metal rubber supports are discussed. The mechanical performance shown by the prototype demonstrates the feasibility of using the SMA-MR concept for active vibration control in rotordynamics, in particular at high temperatures and large amplitude vibrations. (paper)

  1. Recovering metallic fractions from waste electrical and electronic equipment by a novel vibration system

    International Nuclear Information System (INIS)

    Habib, Muddasar; Miles, Nicholas J.; Hall, Philip

    2013-01-01

    Highlights: ► This work focuses on demonstrating a new scaled up technology to separate the metallic and non-metallic fractions of PCBs. ► PCBs comminuted to <1 mm in size resulted in metallic grade concentration of 95% in some of the recovered products. ► Good separation was observed at 40 mm particle bed height due to the formation of well-structured global convection currents. ► The work reported here contributes to the development of a new approach to dry, fine particle separation. - Abstract: The need to recover and recycle valuable resources from Waste Electrical and Electronic Equipment (WEEE) is of growing importance as increasing amounts are generated due to shorter product life cycles, market expansions, new product developments and, higher consumption and production rates. The European Commission (EC) directive, 2002/96/EC, on WEEE became law in UK in January 2007 setting targets to recover up to 80% of all WEEE generated. Printed Wire Board (PWB) and/or Printed Circuit Board (PCB) is an important component of WEEE with an ever increasing tonnage being generated. However, the lack of an accurate estimate for PCB production, future supply and uncertain demands of its recycled materials in international markets has provided the motivation to explore different approaches to recycle PCBs. The work contained in this paper focuses on a novel, dry separation methodology in which vertical vibration is used to separate the metallic and non-metallic fractions of PCBs. When PCBs were comminuted to less than 1 mm in size, metallic grades as high as 95% (measured by heavy liquid analysis) could be achieved in the recovered products

  2. Vibration of fuel bundles

    International Nuclear Information System (INIS)

    Chen, S.S.

    1975-06-01

    Several mathematical models have been proposed for calculating fuel rod responses in axial flows based on a single rod consideration. The spacing between fuel rods in liquid metal fast breeder reactors is small; hence fuel rods will interact with one another due to fluid coupling. The objective of this paper is to study the coupled vibration of fuel bundles. To account for the fluid coupling, a computer code, AMASS, is developed to calculate added mass coefficients for a group of circular cylinders based on the potential flow theory. The equations of motion for rod bundles are then derived including hydrodynamic forces, drag forces, fluid pressure, gravity effect, axial tension, and damping. Based on the equations, a method of analysis is presented to study the free and forced vibrations of rod bundles. Finally, the method is applied to a typical LMFBR fuel bundle consisting of seven rods

  3. Anharmonic thermal vibrations of be metal found in the MEM nuclear density map

    International Nuclear Information System (INIS)

    Takata, Masaki; Sakata, Makoto; Larsen, F.K.; Kumazawa, Shintaro; Iversen, B.B.

    1993-01-01

    A direct observation of the thermal vibrations of Be metal was performed by the Maximum Entropy Method (MEM) using neutron single crystal data. In the previous study, the existence of the small but significant cubic anharmonicity of Be has been found by the conventional least squares refinement of the observed structure factors [Larsen, Lehmann and Merisalo (1980) Acta Cryst. A36, 159-163]. In the present study, the same data were used for the MEM analysis which are comprised of 48 reflections up to sinθ/λ = 1.41A -1 in order to obtain the high resolution nuclear density of Be without using any thermal vibrational model. It was directly visible in the MEM map that not only the cubic terms but also quartic anharmonicities exist in the thermal vibrations of Be nuclei. In order to evaluate thermal parameters of Be including anharmonic terms quantitatively, the least squares refinement of the effective one-particle potential (OPP) parameters up to quartic term was carried out by using the MEM nuclear densities around atomic sites as the data set to be fitted. It was found that the present treatment has a great advantage to decide the most appropriate model of OPP by visually comparing the model with MEM density map. As a result of the least squares refinement, the anharmonic thermal parameters are obtained as α 33 = -0.340(5)[eV/A 3 ], α 40 = 0, β 20 = 9.89(1)[eV/A 4 ] and γ 00 = 0. No other anharmonic term was significant. (author)

  4. Circular Coinduction

    Science.gov (United States)

    Rosu, Grigore; Goguen, Joseph; Norvig, Peter (Technical Monitor)

    2001-01-01

    Circular coinduction is a technique for behavioral reasoning that extends cobasis coinduction to specifications with circularities. Because behavioral satisfaction is not recursively enumerable, no algorithm can work for every behavioral statement. However. algorithms using circular coinduction can prove every practical behavioral result that we know. This paper proves the correctness of circular coinduction and some consequences.

  5. Reliability of vibration energy harvesters of metal-based PZT thin films

    Science.gov (United States)

    Tsujiura, Y.; Suwa, E.; Kurokawa, F.; Hida, H.; Kanno, I.

    2014-11-01

    This paper describes the reliability of piezoelectric vibration energy harvesters (PVEHs) of Pb(Zr,Ti)O3 (PZT) thin films on metal foil cantilevers. The PZT thin films were directly deposited onto the Pt-coated stainless-steel (SS430) cantilevers by rf-magnetron sputtering, and we observed their aging behavior of power generation characteristics under the resonance vibration condition for three days. During the aging measurement, there was neither fatigue failure nor degradation of dielectric properties in our PVEHs (length: 13 mm, width: 5.0 mm, thickness: 104 μm) even under a large excitation acceleration of 25 m/s2. However, we observed clear degradation of the generated electric voltage depending on excitation acceleration. The decay rate of the output voltage was 5% from the start of the measurement at 25 m/s2. The transverse piezoelectric coefficient (e31,f) also degraded with almost the same decay rate as that of the output voltage; this indicates that the degradation of output voltage was mainly caused by that of piezoelectric properties. From the decay curves, the output powers are estimated to degrade 7% at 15 m/s2 and 36% at 25 m/s2 if we continue to excite the PVEHs for 30 years.

  6. Reliability of vibration energy harvesters of metal-based PZT thin films

    International Nuclear Information System (INIS)

    Tsujiura, Y; Suwa, E; Kurokawa, F; Hida, H; Kanno, I

    2014-01-01

    This paper describes the reliability of piezoelectric vibration energy harvesters (PVEHs) of Pb(Zr,Ti)O 3 (PZT) thin films on metal foil cantilevers. The PZT thin films were directly deposited onto the Pt-coated stainless-steel (SS430) cantilevers by rf-magnetron sputtering, and we observed their aging behavior of power generation characteristics under the resonance vibration condition for three days. During the aging measurement, there was neither fatigue failure nor degradation of dielectric properties in our PVEHs (length: 13 mm, width: 5.0 mm, thickness: 104 μm) even under a large excitation acceleration of 25 m/s 2 . However, we observed clear degradation of the generated electric voltage depending on excitation acceleration. The decay rate of the output voltage was 5% from the start of the measurement at 25 m/s 2 . The transverse piezoelectric coefficient (e 31,f ) also degraded with almost the same decay rate as that of the output voltage; this indicates that the degradation of output voltage was mainly caused by that of piezoelectric properties. From the decay curves, the output powers are estimated to degrade 7% at 15 m/s 2 and 36% at 25 m/s 2 if we continue to excite the PVEHs for 30 years

  7. Femtosecond investigation of electronic and vibrational dynamics of metal nano-objects and local order in glasses

    International Nuclear Information System (INIS)

    Burgin, Julien

    2007-01-01

    In this Ph.D. work we have investigated the electronic and vibrational properties of metallic nano objects as a function of their size, shape and composition, and studied the vibrational modes in glasses, using femtosecond time-resolved spectroscopy. In mono-metallic copper clusters, acceleration of the electron-lattice energy exchanges for sizes smaller than 10 nm has been demonstrated, confirming previous results in gold and silver clusters. The small size regime, i.e., nanoparticles smaller than 2 nm, has been addressed. The results show the limit of the classical confined material approach. In bi-metallic clusters, electron-lattice interaction has been shown to reflect their composition for gold-silver materials, but exhibits a more complex behavior in the case of segregated nickel-silver particles. The impact of shape, structure and environment on the acoustic vibrations of metallic nano-objects has also been studied. Measurements performed in ensemble or pairs of prisms yielded evidence for local fluctuations of their coupling with the substrate. Nano-structuration effects have been demonstrated in nano-columns and segregated components. The vibrational modes associated to local order in glasses have been investigated using a high sensitivity impulsive stimulated Raman scattering technique. The 'defect modes' of normal and densified silica, associated to vibrations of ring structures, have been observed and characterized, yielding information on the evolution of the ring density. Performing similar measurements in germania, we have demonstrated the existence of a vibrational mode due to a similar ring structure and determined its characteristics [fr

  8. Ab-initio vibrational properties of transition metal chalcopyrite alloys determined as high-efficiency intermediate-band photovoltaic materials

    International Nuclear Information System (INIS)

    Palacios, P.; Aguilera, I.; Wahnon, P.

    2008-01-01

    In this work, we present frozen phonon and linear response ab-initio research into the vibrational properties of the CuGaS 2 chalcopyrite and transition metal substituted (CuGaS 2 )M alloys. These systems are potential candidates for developing a novel solar-cell material with enhanced optoelectronic properties based in the implementation of the intermediate-band concept. We have previously carried out ab-initio calculations of the electronic properties of these kinds of chalcopyrite metal alloys showing a narrow transition metal band isolated in the semiconductor band gap. The substitutes used in the present work are the 3d metal elements, Titanium and Chromium. For the theoretical calculations we use standard density functional theory at local density and generalized gradient approximation levels. We found that the optical phonon branches of the transition metal chalcopyrite, are very sensitive to the specific bonding geometry and small changes in the transition metal environment

  9. Experimental Study of Pressure Drop and Wall Shear Stress Characteristics of γ /Al2O3-Water Nanofluid in a Circular pipe under Turbulent flow induced vibration.

    Directory of Open Access Journals (Sweden)

    Adil Abbas AL-Moosawy

    2016-09-01

    Full Text Available Experimental study of γ /Al2O3 with mean diameter of less than 50 nm was dispersed in the distilled water that flows through a pipe consist of five sections as work station ,four sections made of carbon steel metal and one sections made of Pyrex glass pipe, with five nanoparticles volume concentrations of 0%,0.1%,0.2%,0.3%,and 0.4% with seven different volume flow rates 100, 200 , 300, 400, 500, 600 ,and 700ℓ/min were investigated to calculated pressure distribution for the cases without rubber ,with 3mm rubber and with 6mm rubber used to support the pipe. Reynolds number was between 20000 and 130000. Frequency value through pipe was measured for all stations of pipe for all cases. The results show that the pressure drop and wall shear stress of the nanofluid increase by increasing the nanoparticles volume concentrations or Reynolds number, the values of frequency through the pipe increase continuously when wall shear stress increases and the ratio of increment increases as nanofluid concentrations increase. Increasing of vibration frequency lead to increasing the friction factor between the pipe and the wall and thus increasing in pressure drop. Several equations between the wall shear stress and frequency for all volume concentration and for three cases without rubber, with rubber has 3mm thickness ,and with rubber has 6mm thickness. Finally, the results led to that γ /Al2O3 could function as a good and alternative conventional working fluid in heat transfer applications. A good agreement is seen between the experimental and those available in the literature

  10. Administrative circular

    CERN Multimedia

    2003-01-01

    • N° 21 - August 2003 Special leave This circular has been amended. Copies of this circular are available in the Divisional Secretariats. In addition, administrative and operational circulars, as well as the lists of those in force, are available for consultation on the Web at: http://cern.ch/hr-div/internal/admin_services/admincirc/listadmincirc.asp Human Resources Division Tel. 74128

  11. Circular Solutions

    NARCIS (Netherlands)

    Annevelink, E.; Bos, H.L.; Meesters, K.P.H.; Oever, van den M.J.A.; Haas, de W.; Kuikman, P.J.; Rietra, R.P.J.J.; Sikirica, N.

    2016-01-01

    The fifth part of this report on Circular Solutions is about the circular principle From Waste to Resource. The purpose of this study is to select promising options for the implementation of this circular principle and to elaborate these options further.

  12. Synthesis, characterization, vibrational spectroscopy, and factor group analysis of partially metal-doped phosphate materials

    Science.gov (United States)

    Sronsri, Chuchai; Boonchom, Banjong

    2018-04-01

    A simple precipitating method was used to synthesize effectively a partially metal-doped phosphate hydrate (Mn0.9Mg0.1HPO4·3H2O), whereas the thermal decomposition process of the above hydrate precursor was used to obtain Mn1.8Mg0.2P2O7 and LiMn0.9Mg0.1PO4 compounds under different conditions. To separate the overlapping thermal decomposition peak, a deconvolution technique was used, and the separated peak was applied to calculate the water content. The factor group splitting analysis was used to exemplify their vibrational spectra obtained from normal vibrations of HPO42-, H2O, P2O74- and PO43- functional groups. Further, the deconvoluted bending mode of water was clearly observed. Mn0.9Mg0.1HPO4·3H2O was observed in the orthorhombic crystal system with the space group of Pbca (D2h15). The formula units per unit cell were found to be eight (Z = 8), and the site symmetric type of HPO42- was observed as Cs. For the HPO42- unit, the correlation filed splitting analysis of type C3v - Cs - D2h15 was calculated and had 96 internal modes, whereas H2O in the above hydrate was symbolized as C2v - Cs - D2h15 and had 24 modes. The symbol C2v - Cs - C2h3 was used for the correlation filed splitting analysis of P2O74- in Mn1.8Mg0.2P2O7 (monoclinic, C2/m (C2h3), Z = 2, and 42 modes). Finally, the symbol Td - Cs - D2h16 was used for the correlation filed splitting analysis of PO43- in LiMn0.9Mg0.1PO4 (orthorhombic, Pnma (D2h16), Z = 4, and 36 modes).

  13. Computational study of heat transfer from the inner surface of a circular tube to force high temperature liquid metal flow in laminar and transition regions

    Science.gov (United States)

    Hata, K.; Fukuda, K.; Masuzaki, S.

    2018-03-01

    transfer. The general correlation in the laminar and turbulent regions for a high temperature liquid metal was identified for the circular tube with a hydraulic diameter.

  14. Information Circulars

    International Nuclear Information System (INIS)

    1969-01-01

    Information circulars are published from time to time under the symbol INFCIRC/. . . . for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A list of the circulars which were of current interest on 15 January 1969 is given below, followed by an index to their subject matter. Other circulars can be traced by reference to earlier issues of the present document.

  15. Information Circulars

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1969-01-24

    Information circulars are published from time to time under the symbol INFCIRC/. . . . for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A list of the circulars which were of current interest on 15 January 1969 is given below, followed by an index to their subject matter. Other circulars can be traced by reference to earlier issues of the present document.

  16. Information circulars

    International Nuclear Information System (INIS)

    1997-02-01

    The document summarizes the Information Circulars published by the IAEA for the purpose of bringing matters of general interest to the attention of all Member States. This revision contains INFCIRCs published up to February 1997, grouped by field of activity. A complete list of information circulars in numerical order is given in an annex

  17. Information circulars

    International Nuclear Information System (INIS)

    2002-05-01

    Information circulars are published from time to time under the symbol INFCIRC/... for the purpose of bringing matters of general interest to the attention of all Members of the Agency. The present revision contains INFCIRCs published up to the end of April 2002. A complete numerical list of information circulars is reproduced with their titles in the Annex

  18. Information circulars

    International Nuclear Information System (INIS)

    1999-06-01

    The document summarizes the Information Circulars published by the IAEA for the purpose of bringing matters of general interest to the attention of all Member States. This revision contains INFCIRCs published up to the end of May 1999, grouped by field of activity. A complete list of information circulars in numerical order is given in an annex

  19. Information circulars

    International Nuclear Information System (INIS)

    1994-08-01

    Information circulars are published from time to time under the symbol INFCIRC/... for the purpose of bringing matters of general interest to the attention of all Members of the Agency. The present revision contains INFCIRCs published up to mid-August 1994. A complete numerical list of information circulars is reproduced with their titles in the Annex

  20. Information circulars

    International Nuclear Information System (INIS)

    1992-08-01

    The document summarizes the Information Circulars published by the IAEA for the purpose of bringing matters of general interest to the attention of all Members of the Agency. This revision contains INFCIRCs published up to mid-August 1992. A complete numerical lift of Information Circulars with their titles is reproduced in an Annex

  1. Information Circulars

    International Nuclear Information System (INIS)

    1966-01-01

    Information circulars are published from time to time under the symbol INFCIRC/. . . . for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A list of the circulars that were current or on the press on 15 May 1966 is given, followed by an index to their subject matter.

  2. Information Circulars

    International Nuclear Information System (INIS)

    1965-01-01

    Information circulars are published from time to time under the symbol INFCIRC/. for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A list of the circulars that were current on 31 December 1964 is given, followed by an index to their subject matter.

  3. Information Circulars

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1966-06-10

    Information circulars are published from time to time under the symbol INFCIRC/. . . . for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A list of the circulars that were current or on the press on 15 May 1966 is given, followed by an index to their subject matter.

  4. Information Circulars

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1965-01-18

    Information circulars are published from time to time under the symbol INFCIRC/. for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A list of the circulars that were current on 31 December 1964 is given, followed by an index to their subject matter.

  5. Towards a scalable and accurate quantum approach for describing vibrations of molecule–metal interfaces

    Directory of Open Access Journals (Sweden)

    David M. Benoit

    2011-08-01

    Full Text Available We present a theoretical framework for the computation of anharmonic vibrational frequencies for large systems, with a particular focus on determining adsorbate frequencies from first principles. We give a detailed account of our local implementation of the vibrational self-consistent field approach and its correlation corrections. We show that our approach is both robust, accurate and can be easily deployed on computational grids in order to provide an efficient computational tool. We also present results on the vibrational spectrum of hydrogen fluoride on pyrene, on the thiophene molecule in the gas phase, and on small neutral gold clusters.

  6. Electronic, vibrational and related properties of group IV metal oxides by ab initio calculations

    International Nuclear Information System (INIS)

    Leite Alves, H.W.; Silva, C.C.; Lino, A.T.; Borges, P.D.; Scolfaro, L.M.R.; Silva, E.F. da

    2008-01-01

    We present our theoretical results for the structural, electronic, vibrational and optical properties of MO 2 (M = Sn, Zr, Hf and Ti) obtained by first-principles calculations. Relativistic effects are demonstrated to be important for a realistic description of the detailed structure of the electronic frequency-dependent dielectric function, as well as of the carrier effective masses. Based on our results, we found that the main contribution of the high values calculated for the oxides dielectric constants arises from the vibrational properties of these oxides, and the vibrational static dielectric constant values diminish with increasing pressure

  7. Information Circulars

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1973-09-10

    Information circulars are published from time to time under the symbol INFCIRC/.. for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A subject index to the circulars is presented overleaf. It covers all those published in the last five years (that is, since the beginning of 1968 and ending with INFCIRC/192), as well as others which, for one reason or another, are still considered to be of current rather than merely historical interest. Such circulars can be traced by reference to the indexes that were included in earlier revisions of the present document.

  8. Information Circulars

    International Nuclear Information System (INIS)

    1973-01-01

    Information circulars are published from time to time under the symbol INFCIRC/.. for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A subject index to the circulars is presented overleaf. It covers all those published in the last five years (that is, since the beginning of 1968 and ending with INFCIRC/192), as well as others which, for one reason or another, are still considered to be of current rather than merely historical interest. Such circulars can be traced by reference to the indexes that were included in earlier revisions of the present document.

  9. Circular Updates

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Circular Updates are periodic sequentially numbered instructions to debriefing staff and observers informing them of changes or additions to scientific and specimen...

  10. Information circulars

    International Nuclear Information System (INIS)

    1987-06-01

    The document summarizes the information circulars published by the IAEA for the purpose of bringing matters of general interest to the attention of all Members of the Agency. In the main body of the document only those documents which are regarded as likely to be of current interest are listed. A complete numerical list of information circulars with their titles is reproduced in the Annex

  11. Modeling and Characteristic Analysis of Wireless Ultrasonic Vibration Energy Transmission Channels through Planar and Curved Metal Barriers

    Directory of Open Access Journals (Sweden)

    DingXin Yang

    2018-01-01

    Full Text Available Wireless ultrasonic vibration energy transmission systems through metal barriers based on piezoelectric transducers have drawn a lot of focus due to the advantage of nonpenetration of the barriers, thus maintaining the integrity of sealed structures. It is meaningful to investigate appropriate modeling methods and to characterize such wireless ultrasonic energy transmission channels with different geometric shapes. In this paper, equivalent circuit modeling and finite element modeling methods are applied to the planar metal barrier channel, and a 3-dimensional finite element modeling method is applied to the cylindrical metallic barrier channel. Meanwhile, the experimental setup is established and measurements are carried out to validate the effectiveness of the corresponding modeling methods. The results show that Leach’s equivalent circuit modeling method and finite element modeling method are nearly similarly effective in characterizing the planar metal barrier channel. But for a cylindrical metal barrier, only the three-dimensional finite element modeling method is effective. Furthermore, we found that, for the planar barrier, the effect of standing waves on the efficiency of wireless energy transmission is dominated. But for the curved barrier, only the resonant phenomenon of the piezoelectric transducer exists.

  12. Free Vibration Analysis of Fiber Metal Laminate Annular Plate by State-Space Based Differential Quadrature Method

    Directory of Open Access Journals (Sweden)

    G. H. Rahimi

    2014-01-01

    Full Text Available A three-dimensional elasticity theory by means of a state-space based differential quadrature method is presented for free vibration analysis of fiber metal laminate annular plate. The kinds of composite material and metal layers are considered to be S2-glass and aluminum, respectively. A semianalytical approach which uses state-space in the thickness and differential quadrature in the radial direction is implemented for evaluating the nondimensional natural frequencies of the annular plates. The influences of changes in boundary condition, plate thickness, and lay-up direction on the natural frequencies are studied. A comparison is also made with the numerical results reported by ABAQUS software which shows an excellent agreement.

  13. Generalized vibrating potential model for collective excitations in spherical, deformed and superdeformed systems: (1) atomic nuclei, (2) metal clusters

    International Nuclear Information System (INIS)

    Nesterenko, V.O.; Kleinig, W.

    1995-01-01

    The self-consistent vibrating potential model (VPM) is extended for description of Eλ collective excitations in atomic nuclei and metal clusters with practically any kind of static deformation. The model is convenient for a qualitative analysis and provides the RPA accuracy of numerical calculations. The VPM is applied to study Eλ giant resonances in spherical metal clusters and deformed and superdeformed nuclei. It is shown that the deformation splitting of superdeformed nuclei results in a very complicated (''jungle-like'') structure of the resonances, which makes the experimental observation of E2 and E3 giant resonances in superdeformed nuclei quite problematic. Calculations of E1 giant resonance in spherical sodium clusters Na 8 , Na 20 and Na 40 are presented, as a test of the VPM in this field. The results are in qualitative agreement with the experimental data. (orig.)

  14. ROLE OF DISCRETE NATURE OF CHIP FORMATION AND NATURAL VIBRATIONS OF SYSTEM COMPONENTS IN CHATTER FORMATION DURING METAL CUTTING

    Directory of Open Access Journals (Sweden)

    A. K. M. Nurulamin

    2010-05-01

    Full Text Available In the present work a review of the existing theories of chatter formation has been conducted and the weaknesses of the most widely accepted ‘Regenerative Chatter theory’ in explaining various phenomena related to chatter formation have been identified. An attempt has been made in this work to determine the common causes of chatter formation in different metal cutting operations, namely, turning, thread cutting and end milling conducted on plain carbon steel AISI 1040. Experimental investigations have been conducted during the above types of machining processes to identify the marks of instability and chatter on the formed chips. It has been identified that in all the three machining operations the chips formed show a common type of discreteness in the form of secondary saw teeth, which appear at the free edge of the chip. Mechanism of formation of these teeth has been studied and the frequencies of their formation have been determined for different cutting conditions. Apart from the secondary saw teeth primary saw teeth have also been identified at the main section of the chip and their frequencies were also determined. At the same time the natural vibrations of the main system components have been identified and the acceleration amplitudes at the prominent natural frequencies during actual machining were recoded using a dedicated vibration monitoring system. The frequencies of secondary chip serration and the natural frequencies of the system components were plotted against cutting speed. Acceleration amplitudes at the prominent natural frequencies were also plotted separately against cutting force. Based on comparison and analysis of these two frequency and amplitude graphs it was concluded that chatter (vibration with relatively high amplitude appears in the system when the frequency of secondary saw teeth approaches values equal to half or integer multiple of a prominent natural frequency of the system resulting in resonance. In the

  15. Operational Circulars

    CERN Multimedia

    2003-01-01

    Operational Circular N° 4 - April 2003 Conditions for use by members of the CERN personnel of vehicles belonging to or rented by CERN - This circular has been drawn up. Operational Circular N° 5 - October 2000 Use of CERN computing facilities - Further details on the personal use of CERN computing facilities Operational Circular N° 5 and its Subsidiary Rules http://cern.ch/ComputingRules defines the rules for the use of CERN computing facilities. One of the basic principles governing such use is that it must come within the professional duties of the user concerned, as defined by the user's divisional hierarchy. However, personal use of the computing facilities is tolerated or allowed provided : a) It is in compliance with Operational Circular N° 5 and not detrimental to official duties, including those of other users; b) the frequency and duration is limited and there is a negligible use of CERN resources; c) it does not constitute a political, commercial and/or profit-making activity; d) it is not...

  16. Investigating vibrational anharmonic couplings in cyanide-bridged transition metal mixed valence complexes using two-dimensional infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Slenkamp, Karla M.; Lynch, Michael S.; Van Kuiken, Benjamin E.; Brookes, Jennifer F.; Bannan, Caitlin C.; Daifuku, Stephanie L.; Khalil, Munira, E-mail: mkhalil@chem.washington.edu [Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195 (United States)

    2014-02-28

    Using polarization-selective two-dimensional infrared (2D IR) spectroscopy, we measure anharmonic couplings and angles between the transition dipole moments of the four cyanide stretching (ν{sub CN}) vibrations found in [(NH{sub 3}){sub 5}Ru{sup III}NCFe{sup II}(CN){sub 5}]{sup −} (FeRu) dissolved in D{sub 2}O and formamide and [(NC){sub 5}Fe{sup II}CNPt{sup IV}(NH{sub 3}){sub 4}NCFe{sup II}(CN){sub 5}]{sup 4−} (FePtFe) dissolved in D{sub 2}O. These cyanide-bridged transition metal complexes serve as model systems for studying the role of high frequency vibrational modes in ultrafast photoinduced charge transfer reactions. Here, we focus on the spectroscopy of the ν{sub CN} modes in the electronic ground state. The FTIR spectra of the ν{sub CN} modes of the bimetallic and trimetallic systems are strikingly different in terms of frequencies, amplitudes, and lineshapes. The experimental 2D IR spectra of FeRu and FePtFe and their fits reveal a set of weakly coupled anharmonic ν{sub CN} modes. The vibrational mode anharmonicities of the individual ν{sub CN} modes range from 14 to 28 cm{sup −1}. The mixed-mode anharmonicities range from 2 to 14 cm{sup −1}. In general, the bridging ν{sub CN} mode is most weakly coupled to the radial ν{sub CN} mode, which involves the terminal CN ligands. Measurement of the relative transition dipole moments of the four ν{sub CN} modes reveal that the FeRu molecule is almost linear in solution when dissolved in formamide, but it assumes a bent geometry when dissolved in D{sub 2}O. The ν{sub CN} modes are modelled as bilinearly coupled anharmonic oscillators with an average coupling constant of 6 cm{sup −1}. This study elucidates the role of the solvent in modulating the molecular geometry and the anharmonic vibrational couplings between the ν{sub CN} modes in cyanide-bridged transition metal mixed valence complexes.

  17. Numerical investigation of the vortex-induced vibration of an elastically mounted circular cylinder at high Reynolds number (Re = 104 and low mass ratio using the RANS code.

    Directory of Open Access Journals (Sweden)

    Niaz Bahadur Khan

    Full Text Available This study numerically investigates the vortex-induced vibration (VIV of an elastically mounted rigid cylinder by using Reynolds-averaged Navier-Stokes (RANS equations with computational fluid dynamic (CFD tools. CFD analysis is performed for a fixed-cylinder case with Reynolds number (Re = 104 and for a cylinder that is free to oscillate in the transverse direction and possesses a low mass-damping ratio and Re = 104. Previously, similar studies have been performed with 3-dimensional and comparatively expensive turbulent models. In the current study, the capability and accuracy of the RANS model are validated, and the results of this model are compared with those of detached eddy simulation, direct numerical simulation, and large eddy simulation models. All three response branches and the maximum amplitude are well captured. The 2-dimensional case with the RANS shear-stress transport k-w model, which involves minimal computational cost, is reliable and appropriate for analyzing the characteristics of VIV.

  18. Information circulars

    International Nuclear Information System (INIS)

    1989-04-01

    The document summarizes the Information Circulars published by the IAEA under the symbol INFCIRC/ for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A complete list of INFCIRCs in numerical order with their titles is given in the Annex

  19. Resonant vibrations of self-interstitials in fcc metals with application to specific heat and neutron scattering

    International Nuclear Information System (INIS)

    Ram, P.N.; Dederichs, P.H.

    1981-07-01

    Some aspects of resonant vibrations of self-interstitials in the 100-dumbbell configuration in fcc-metals are discussed by extending previous calculations of Zeller et al. and Schober et al. Employing a simple defect model with nearest-neighbour interaction the local frequency spectrum of the defect is calculated showing several localized modes and low-frequency resonant modes. The change in the total density of states due to the defects is expressed as the derivative of a generalized phase shift which is used to calculate the change in the lattic specific heat due to single interstitials. Inelastic neutron scattering away from the one-phonon lines is proposed as a method to observe the resonant modes induced by self-interstitials. The model calculation in Cu shows that the well defined resonant modes due to dumbbell vibrations have appreciable intensity and could presumably be detected in neutron scattering measurements. The effect of di-interstitials on the phonon dispersion in Al is also discussed. (orig./GSCH)

  20. Noncentral forces and lattice vibration in transition metals. Alpha-iron, chromium, and tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V P; Kharoo, H L; Kumar, M; Hemkar, M P [Allahabad Univ. (India). Dept. of Physics

    1976-03-11

    The elastic-force model proposed in a previous paper has been considered to compute the phonon dispersion relations for lattice waves propagating along the principal symmetry directions of ..cap alpha..-iron, chromium and tungsten. The model, however, takes into account the central forces together with the Clark, Gazis and Wallis type angular forces and the effect of electron-iron interaction on the lattice vibration as outlined by Krebs. The theoretical results are found to be quite satisfactory and compare well with recent neutron scattering data.

  1. ADMINISTRATIVE CIRCULARS

    CERN Multimedia

    Division des ressources humaines

    2000-01-01

    N° 2 (Rev. 1) - March 2000Guidelines and procedures concerning recruitment and probation period of staff membersN° 9 (Rev. 2) - March 2000Staff members contractsN° 16 (Rev. 2) - January 2000TrainingN° 30 (Rev. 1) - January 2000Indemnities and reimbursements upon taking up appointment and termination of contractN° 32 - February 2000Principles and procedures governing complaints of harassmentThese circular have been amended (No 2, N° 9, N° 16 and N° 30) or drawn up (N° 32).Copies are available in the Divisional Secretariats.Note:\tAdministrative and operational circulars, as well as the lists of those in force, are available for consultation in the server SRV4_Home in the Appletalk zone NOVELL (as GUEST or using your Novell username and password), volume PE Division Data Disk.The Word files are available in the folder COM, folder Public, folder ADM.CIRC.docHuman Resources DivisionTel. 74128

  2. Circular RNAs

    DEFF Research Database (Denmark)

    Han, Yi-Neng; Xia, Shengqiang; Zhang, Yuan-Yuan

    2017-01-01

    Circular RNAs (circRNAs) are a novel type of universal and diverse endogenous noncoding RNAs (ncRNAs) and they form a covalently closed continuous loop without 5' or 3' tails unlike linear RNAs. Most circRNAs are presented with characteristics of abundance, stability, conservatism, and often exhi...... and expression regulators, RBP sponges in cancer as well as current research methods of circRNAs, providing evidence for the significance of circRNAs in cancer diagnosis and clinical treatment....

  3. Synthesis, vibrational spectrometry and thermal characterizations of coordination polymers derived from divalent metal ions and hydroxyl terminated polyurethane as ligand

    Science.gov (United States)

    Laxmi; Khan, Shabnam; Kareem, Abdul; Zafar, Fahmina; Nishat, Nahid

    2018-01-01

    A series of novel coordination polyurethanes [HTPU-M, where M = Mn(II) 'd5', Ni(II) 'd8', and Zn(II) 'd10'] have been synthesized to investigate the effect of divalent metal ions coordination on structure, thermal and adsorption properties of low molecular weight hydroxyl terminated polyurethane (HTPU). HTPU-M have been synthesized in situ where, sbnd OH group of HTPU (synthesized by the condensation polymerization reaction of ethylene glycol (EG) and toluene diisocyanate (TDI) in presence of catalyst) on condensation polymerization with metal acetate in presence of acid catalyst synthesized HTPU-M followed by coordination of metal ions with hetero atoms. The structure, composition and geometry of HTPU-M have been confirmed by vibrational spectrometry (FTIR), 1H NMR, elemental analysis and UV-Visible spectroscopy. Morphological structures of HTPU-M were analyzed by X-Ray Diffraction analysis (XRD), Field Emission Scanning Electron Microscope (FE-SEM) with Energy Dispersive X-ray spectroscopy (EDX) and High Resolution Transmission Electron Microscope (HR-TEM) techniques. The thermal degradation pattern and thermal stability of HTPU-M in comparison to HTPU was investigated by thermal-gravimetric (TG)/differential thermal (DT), analyses along with Integral procedure decomposition temperature (IPDT) by Doyle method. The molecular weight of HTPU was determined by gel permeation chromatography (GPC). The preliminary adsorption/desorption studies of HTPU-M for Congo red (CR) was studied by batch adsorption techniques. The results indicated that HTPU-M have amorphous, layered morphology with higher number of nano-sized grooves in comparison to HTPU. Coordination of metal to HTPU plays a key role in enhancing the thermal stability [HTPU-Ni(II) > HTPU-Mn(II) > HTPU-Zn(II) > HTPU]. The HTPU-M can be utilized for industrial waste water treatment by removing environmental pollutants.

  4. Effective information campaign for management of exposure to hand-arm vibration in the metal and construction industries.

    Science.gov (United States)

    Sauni, Riitta; Toivio, Pauliina; Esko, Toppila; Pääkkönen, Rauno; Uitti, Jukka

    2015-01-01

    European Directive 2002/44/EC defines employers' responsibilities in the risk management of hand-arm vibration (HAV). However, the directive is still not completely implemented in all risk industries. The aim of our study was to determine whether it is possible to improve the recognition and management of the risks of HAV at workplaces with a one-year information campaign. A questionnaire on opinions and measures for controlling HAV exposure at workplaces was sent to all occupational safety representatives and occupational safety managers in the construction and metal industry in Finland (n=1887) and once again to those who responded to the first questionnaire (n=961) one year after the campaign. The campaign increased recognition of HAV in risk assessment from 57.0% to 68.3% (p=.001), increased measures to decrease exposure to HAV from 54.6% to 64.2% (p=.006) and increased the number of programmes to control the risks due to HAV (p<.001). The information campaign, which focuses on the construction and metal industries, proved to be effective in increasing the awareness of the risks of HAV and the measures needed to control exposure to HAV. A similar campaign can be recommended in the case of risks specific to certain occupations.

  5. Magnetic field integral equation analysis of interaction between a surface plasmon polariton and a circular dielectric cavity embedded in the metal.

    Science.gov (United States)

    Chremmos, Ioannis

    2009-12-01

    A rigorous integral equation (IE) analysis of the interaction between a surface plasmon polariton (SPP) and a circular dielectric cavity embedded in a metal half-space is presented. The device is addressed as the plasmonic counterpart of the established integrated optics filter comprising a whispering gallery (WG) resonator coupled to a waveguide. The mathematical formulation is that of a transverse magnetic scattering problem. Using a magnetic-type Green's function of the two-layer medium with boundary conditions that cancel the line integral contributions along the interface, an IE for the magnetic field inside the cavity is obtained. The IE is treated through an entire-domain method of moments (MoM) with cylindrical-harmonic basis functions. The entries of the MoM matrix are determined analytically by utilizing the inverse Fourier transform of Green's function and the Jacobi-Anger formula for interchanging between plane and cylindrical waves. Complex analysis techniques are applied to determine the transmitted, reflected, and radiated field quantities in series forms. The numerical results show that the scattered SPPs' spectra exhibit pronounced wavelength selectivity that is related to the excitation of WG-like cavity modes. It seems feasible to exploit the device as a bandstop or reflective filter or even as an efficient radiating element. In addition, the dependence of transmission on the cavity refractive index endows this structure with a sensing functionality.

  6. Oriented circular dichroism analysis of chiral surface-anchored metal-organic frameworks grown by liquid-phase epitaxy and upon loading with chiral guest compounds

    KAUST Repository

    Gu, Zhigang

    2014-06-17

    Oriented circular dichroism (OCD) is explored and successfully applied to investigate chiral surface-anchored metal-organic frameworks (SURMOFs) based on camphoric acid (D- and Lcam) with the composition [Cu2(Dcam) 2x(Lcam)2-2x(dabco)]n (dabco=1,4-diazabicyclo- [2.2.2]-octane). The three-dimensional chiral SURMOFs with high-quality orientation were grown on quartz glass plates by using a layer-by-layer liquid-phase epitaxy method. The growth orientation, as determined by X-ray diffraction (XRD), could be switched between the [001] and [110] direction by using either OH- or COOH-terminated substrates. These SURMOFs were characterized by using OCD, which confirmed the ratio as well as the orientation of the enantiomeric linker molecules. Theoretical computations demonstrate that the OCD band intensities of the enantiopure [Cu2(Dcam)2(dabco)] n grown in different orientations are a direct result of the anisotropic nature of the chiral SURMOFs. Finally, the enantiopure [Cu 2(Dcam)2(dabco)]n and [Cu2(Lcam) 2(dabco)]n SURMOFs were loaded with the two chiral forms of ethyl lactate [(+)-ethyl-D-lactate and (-)-ethyl-L-lactate)]. An enantioselective enrichment of >60 % was observed by OCD when the chiral host scaffold was loaded from the racemic mixture. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Oriented circular dichroism analysis of chiral surface-anchored metal-organic frameworks grown by liquid-phase epitaxy and upon loading with chiral guest compounds

    KAUST Repository

    Gu, Zhigang; Bü rck, Jochen; Bihlmeier, Angela; Liu, Jinxuan; Shekhah, Osama; Weidler, Peter G.; Azucena, Carlos; Wang, Zhengbang; Heiß ler, Stefan; Gliemann, Hartmut; Klopper, Wim; Ulrich, Anne S.; Wö ll, Christof H.

    2014-01-01

    Oriented circular dichroism (OCD) is explored and successfully applied to investigate chiral surface-anchored metal-organic frameworks (SURMOFs) based on camphoric acid (D- and Lcam) with the composition [Cu2(Dcam) 2x(Lcam)2-2x(dabco)]n (dabco=1,4-diazabicyclo- [2.2.2]-octane). The three-dimensional chiral SURMOFs with high-quality orientation were grown on quartz glass plates by using a layer-by-layer liquid-phase epitaxy method. The growth orientation, as determined by X-ray diffraction (XRD), could be switched between the [001] and [110] direction by using either OH- or COOH-terminated substrates. These SURMOFs were characterized by using OCD, which confirmed the ratio as well as the orientation of the enantiomeric linker molecules. Theoretical computations demonstrate that the OCD band intensities of the enantiopure [Cu2(Dcam)2(dabco)] n grown in different orientations are a direct result of the anisotropic nature of the chiral SURMOFs. Finally, the enantiopure [Cu 2(Dcam)2(dabco)]n and [Cu2(Lcam) 2(dabco)]n SURMOFs were loaded with the two chiral forms of ethyl lactate [(+)-ethyl-D-lactate and (-)-ethyl-L-lactate)]. An enantioselective enrichment of >60 % was observed by OCD when the chiral host scaffold was loaded from the racemic mixture. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. A new electron gas model for lattice vibrations in metals I : development of the model

    International Nuclear Information System (INIS)

    Ramamurthy, V.; Neelkandan, K.

    1978-01-01

    The theoretical study of the lattice dynamics of metals is generally based on either the phenomenological force constant method or the pseudopotential method. However, it has been found that all the existing phenomenological models are inconsistent. Hence a new model based on the deformation potential approximation has been developed. By comparing this model with the existing models, its salient features and limitations are discussed. (author)

  9. Structural and vibrational study of 8-hydroxyquinoline-2-carboxaldehyde isonicotinoyl hydrazone - A potential metal-protein attenuating compound (MPAC) for the treatment of Alzheimer's disease

    Science.gov (United States)

    de Freitas, Leonardo Viana; da Silva, Cecilia C. P.; Ellena, Javier; Costa, Luiz Antônio Sodré; Rey, Nicolás A.

    2013-12-01

    A comprehensive structural and vibrational study of the potential metal-protein attenuating compound 8-hydroxyquinoline-2-carboxaldehyde isonicotinoyl hydrazone is reported. X-ray diffraction data, as well as FT-IR and Raman frequencies, were compared with the respective theoretical values obtained from DFT calculations. Theory agrees well with experiment. In this context, an attempt of total assignment concerning the FT-IR and Raman spectra of the title compound was performed, shedding new light on previous partial assignments published elsewhere.

  10. Analysis of functional organic molecules at noble metal surfaces by means of vibrational spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Leyssner, Felix

    2011-10-24

    The goal of this work is to optimize the efficiency of photoinduced molecular switching processes on surfaces via controlled variations of the adsorption and electronic properties of the switch. We investigated the influence of external stimuli, i.e. photons and thermal activation, on surface bound molecular switches undergoing trans/cis-isomerizations and ring-opening/closing-reactions, respectively. High resolution electron energy loss spectroscopy (HREELS) and sum-frequency generation (SFG) spectroscopy have been used as the main tools to investigate the adsorption behavior and the molecular switching properties. Two basic concepts of coupling the molecular switch to the surface have been studied: (i) physisorbed or weakly chemisorbed systems deposited on noble metal surfaces under UHV conditions and (ii) molecular switches bound covalently via anchor groups. In the HREELS study following concept (i), we investigated the adsorption geometry and isomerization behavior of various molecular switches on metal substrates which are able to undergo a photoinduced trans/cis-isomerization in solution. We investigated three isoelectronic molecules on Au where we systematically changed the photochemically active group from the diazo-group in an azobenzene-derivative (on Cu(111)) to the imine-group, and the vinylene-group, respectively. Finding the photoisomerization quenched for all systems we observed considerable differences in their thermal isomerization behavior. Comparable we find the photoinduced ring-opening/closing-reaction of spiropyran quenched on Au(111) but a thermally induced ring-opening reaction resulting in the open form being strongly stabilized by the metal. SFG spectroscopy is employed to investigate the reversible, photoinduced trans/cis-isomerization of an azobenzene-functionalized self-assembled monolayer (SAM) on gold using a tripodal linker system. In consequence of the decoupling provided by the tripodal linker, the switching behavior of the

  11. Vibrational and optical properties of amorphous metals: Progress report, July 1, 1987--June 30, 1988

    International Nuclear Information System (INIS)

    Lannin, J.S.

    1988-02-01

    Substantial progress has been achieved in the three areas of Raman scattering, inelastic neutron scattering and optical studies of amorphous metal alloys. In the Raman area, studies of amorphous disilicides of Ni and W, a-NiSi 2 and a-WSi 2 , were obtained that provide information on both the dynamics and short range order in the amorphous phase. Measurements of the Raman spectra have been compared to the neutron weighted densities of states of the corresponding crystalline systems. A detailed evaluation of the inelastic neutron spectra of the concentrated Ni alloy of a-Ni/sub .95/Tb/sub .05/ has recently been completed. Optical measurements of the real and imaginary parts of the dielectric function of a-Ni/sub .95/Tb/sub .05/ were also performed during this year using the technique of spectroscopic ellipsometry. Raman scattering measurements were performed on the amorphous state of the counterpart of the high temperature superconductor of crystalline YBa 2 Cu 3 O/sub x/

  12. Characterization of alkali-metal and alkaline-earth nitrates by vibrational spectroscopy

    Directory of Open Access Journals (Sweden)

    Martínez, S.

    1992-09-01

    Full Text Available Infrared spectra of sodium and potassium alkaline-metal nitrates and magnesium and calcium alkali-earth nitrates in solid phase had been recorded in order to assign the fundamental bands. The influence of the dispersal médium (alkaline halide, employed in the solid sample preparation have been discussed. The quantitative measurements of the band in ten sities at 1387 cm-1 (present in the I.R. spectra of the four nitrates in KBr médium allowed us to determine the Lambert-Beer law slopes for each compound. These values are differents (bearing in mind experimental random errors, so we have could to affirm the nonexistence of solid solution between the nitrate and the alkaline halide médium. The L-B law obtained by us can be used for the Identification differentiation and quantitative analysis of these nitrates in solid phase, even if they are present in a very low concentration.

    Se ha realizado la asignación de los espectros infrarrojo (IR de los nitratos alcalinos, sódico y potásico, y de los alcalinotérreos, magnésico y cálcico, en estado sólido. Se ha visto la influencia del medio dispersante (haluro alcalino, utilizado en la preparación de la muestra sólida. El estudio cuantitativo de la absorbencia de la banda a 1.387 cm-1 (presente en los espectros IR de los cuatro nitratos en medio KBr permite determinar las pendientes de la Ley de Lambert-Beer Se comprueba que dichas pendientes son diferentes lo que conduce a poder afirmar que no se produce disolución sólida entre el KBr y el nitrato alcalino o alcalinotérreo. La determinación de la ley de Lambert-Beer permite la identificación y el análisis cualitativo y cuantitativo por espectroscopia IR de estos nitratos cuando están presentes en bajas concentraciones en muestras sólidas.

  13. Molecular Structures, Vibrational Spectroscopy, and Normal-Mode Analysis of M(2)(C&tbd1;CR)(4)(PMe(3))(4) Dimetallatetraynes. Observation of Strongly Mixed Metal-Metal and Metal-Ligand Vibrational Modes.

    Science.gov (United States)

    John, Kevin D.; Miskowski, Vincent M.; Vance, Michael A.; Dallinger, Richard F.; Wang, Louis C.; Geib, Steven J.; Hopkins, Michael D.

    1998-12-28

    The nature of the skeletal vibrational modes of complexes of the type M(2)(C&tbd1;CR)(4)(PMe(3))(4) (M = Mo, W; R = H, Me, Bu(t)(), SiMe(3)) has been deduced. Metrical data from X-ray crystallographic studies of Mo(2)(C&tbd1;CR)(4)(PMe(3))(4) (R = Me, Bu(t)(), SiMe(3)) and W(2)(C&tbd1;CMe)(4)(PMe(3))(4) reveal that the core bond distances and angles are within normal ranges and do not differ in a statistically significant way as a function of the alkynyl substituent, indicating that their associated force constants should be similarly invariant among these compounds. The crystal structures of Mo(2)(C&tbd1;CSiMe(3))(4)(PMe(3))(4) and Mo(2)(C&tbd1;CBu(t)())(4)(PMe(3))(4) are complicated by 3-fold disorder of the Mo(2) unit within apparently ordered ligand arrays. Resonance-Raman spectra ((1)(delta-->delta) excitation, THF solution) of Mo(2)(C&tbd1;CSiMe(3))(4)(PMe(3))(4) and its isotopomers (PMe(3)-d(9), C&tbd1;CSiMe(3)-d(9), (13)C&tbd1;(13)CSiMe(3)) exhibit resonance-enhanced bands due to a(1)-symmetry fundamentals (nu(a) = 362, nu(b) = 397, nu(c) = 254 cm(-)(1) for the natural-abundance complex) and their overtones and combinations. The frequencies and relative intensities of the fundamentals are highly sensitive to isotopic substitution of the C&tbd1;CSiMe(3) ligands, but are insensitive to deuteration of the PMe(3) ligands. Nonresonance-Raman spectra (FT-Raman, 1064 nm excitation, crystalline samples) for the Mo(2)(C&tbd1;CSiMe(3))(4)(PMe(3))(4) compounds and for Mo(2)(C&tbd1;CR)(4)(PMe(3))(4) (R = H, D, Me, Bu(t)(), SiMe(3)) and W(2)(C&tbd1;CMe)(4)(PMe(3))(4) exhibit nu(a), nu(b), and nu(c) and numerous bands due to alkynyl- and phosphine-localized modes, the latter of which are assigned by comparisons to FT-Raman spectra of Mo(2)X(4)L(4) (X = Cl, Br, I; L = PMe(3), PMe(3)-d(9))(4) and Mo(2)Cl(4)(AsMe(3))(4). Valence force-field normal-coordinate calculations on the model compound Mo(2)(C&tbd1;CH)(4)P(4), using core force constants transferred from a calculation

  14. Ab initio study of structural, elastic, and vibrational properties of transition-metal disilicides NbSi2 and TaSi2 in hexagonal C40 structure

    Science.gov (United States)

    Ertürk, Esra; Gürel, Tanju

    2018-05-01

    We present an ab initio study of structural, elastic and vibrational properties of transition-metal disilicides NbSi2 and TaSi2. The calculations have been carried out within the density-functional theory and linear-response formalism using norm-conserving pseudopotentials and a plane-wave basis. The calculated lattice parameters, bulk moduli, and elastic constants agree well with previous theoretical and experimental results. The calculated phonon frequencies at the Brillouin zone center are in good agreement with the reported Raman spectra and provide reference values for the future infrared and neutron phonon measurements. Phonon dispersion relations, mode Grüneisen parameters, and total and partial phonon density of states are also discussed. Mode Grüneisen parameters of NbSi2 and TaSi2 at Brillouin zone center show similar trends and all values are found to be positive. From phonon dispersion relations and phonon density of states, we have found a gap around 200 cm-1 for TaSi2, where the frequencies below this gap mainly belong to Ta vibrations and frequencies above the gap is mainly related with Si vibrations. In the case of NbSi2, there is no such gap and both Nb and Si atoms contribute to the phonon density of states in an energy range of 150-270 cm-1.

  15. Changes in the vibrational energies and interatomic spacings upon the formation of vacancies in the volume and in the cores of crystallite conjugation regions of polycrystalline transition metals with cubic lattices

    International Nuclear Information System (INIS)

    Klotsman, S.M.; Timofeev, A.N.

    2008-01-01

    Measured changes (ε vac ) i,j of vibrational energy on vacancies formation in i-fields (in volumes and nuclei of crystallite conjugation regions of polycrystalline metals (CCR-PM)): Cr, Mo, Ta, W, Cu, Ir are presented. Changes ε vol of vibrational energy of vacancy nearest environment formed in the metal volume, changes ε FCC of vibrational energy when vacancies formation in CCR nuclei of BCC- and FCC lattices transition metals are discussed. Measured changes ε FCC of vibrational energy, u FCC potential energy and determined sign of interatomic distances changes Δa FCC when formation of split vacancy in the FCC-lattice CCR-PM, changes ε BCC of vibrational energy, u BCC potential energy and determined sign of Δa BCC changes of interatomic distances when vacancies formation in the BCC-lattice CCR-PM are demonstrated. It is noted that the increase of interatomic distances when vacancies formation in the BCC-lattice CCR nucleus of transition metals is conditioned by the the appearance of vacancies alternative structure. Properties of CCR-PM nuclei are more sensitive to interatomic distances changes in the vacancies environment, than to changes of its nearest neighbours numbers [ru

  16. Administrative Circulars Rev.

    CERN Multimedia

    2003-01-01

    Administrative Circular N° 19 (Rev. 3) - April 2003 Subsistence indemnity - Other expenses necessarily incurred in the course of duty travelAdministrative Circular N° 25 (Rev. 2) - April 2003 Shift work - Special provisions for the Fire and Rescue Service - These circulars have been revised. Human Resources Division Tel. 74128Copies of these circulars are available in the Divisional Secretariats. In addition, administrative and operational circulars, as well as the lists of those in force, are available for consultation on the Web at: http://humanresources.web.cern.ch/humanresources/internal/admin_services/admincirc/listadmincirc.asp

  17. Atomic beams probe surface vibrations

    International Nuclear Information System (INIS)

    Robinson, A.L.

    1982-01-01

    In the last two years, surface scientist have begun trying to obtain the vibrational frequencies of surface atoms in both insulating and metallic crystals from beams of helium atoms. It is the inelastic scattering that researchers use to probe surface vibrations. Inelastic atomic beam scattering has only been used to obtain vibrational frequency spectra from clean surfaces. Several experiments using helium beams are cited. (SC)

  18. Publication of administrative circular

    CERN Multimedia

    HR Department

    2009-01-01

    ADMINISTRATIVE CIRCULAR NO. 23 (REV. 2) – SPECIAL WORKING HOURS Administrative Circular No. 23 (Rev. 2) entitled "Special working hours", approved following discussion in the Standing Concertation Committee on 9 December 2008, will be available on the intranet site of the Human Resources Department as from 19 December 2008: http://cern.ch/hr-docs/admincirc/admincirc.asp It cancels and replaces Administrative Circular No. 23 (Rev. 1) entitled "Stand-by duty" of April 1988. A "Frequently Asked Questions" information document on special working hours will also be available on this site. Paper copies of this circular will shortly be available in Departmental Secretariats. Human Resources Department Tel. 78003

  19. PUBLICATION OF ADMINISTRATIVE CIRCULAR

    CERN Multimedia

    HR Department

    2008-01-01

    ADMINISTRATIVE CIRCULAR NO. 23 (REV. 2) – SPECIAL WORKING HOURS Administrative Circular No. 23 (Rev. 2) entitled "Special working hours", approved following discussion in the Standing Concertation Committee meeting of 9 December 2008, will be available on the intranet site of the Human Resources Department as from 19 December 2008: http://cern.ch/hr-docs/admincirc/admincirc.asp It cancels and replaces Administrative Circular No. 23 (Rev. 1) entitled "Stand-by duty" of April 1988. A "Frequently Asked Questions" information document on special working hours will also be available on this site. Paper copies of this circular will shortly be available in departmental secretariats. Human Resources Department Tel. 78003

  20. Theoretical Prediction of Vibrational Circular Dichroism Spectra of R- Glyceraldehyde, R-Erythrose, and R-Threose. 2. Development of a Procedure to Scale the Force Constant Matrix Expressed in Terms of Internal Coordinates

    Science.gov (United States)

    1993-11-01

    IS PROGRAM NUMBER 1 OF THE COMPLETE VIBRATIONAL PACKAGE. C C BMAT ... WIL.riON B MATRIX ELDEMETS FOR INTERNAL COORDINATES C iVERSIONO JUL 28, 1977) C...MATRIX ISCAN=ISCAN+ 1 IER=O GO TO 30 210 WRITE(6,1120) STOP 1000 FORMAT(20A4/20A4/214) 1010 FORMAT(’l’,20A4,24X.’ BMAT (VERSIONO JUL 28. 1977)’/1X,20A4

  1. The generalized circular model

    NARCIS (Netherlands)

    Webers, H.M.

    1995-01-01

    In this paper we present a generalization of the circular model. In this model there are two concentric circular markets, which enables us to study two types of markets simultaneously. There are switching costs involved for moving from one circle to the other circle, which can also be thought of as

  2. Circularity and Lambda Abstraction

    DEFF Research Database (Denmark)

    Danvy, Olivier; Thiemann, Peter; Zerny, Ian

    2013-01-01

    unknowns from what is done to them, which we lambda-abstract with functions. The circular unknowns then become dead variables, which we eliminate. The result is a strict circu- lar program a la Pettorossi. This transformation is reversible: given a strict circular program a la Pettorossi, we introduce...

  3. Towards Circular Business Models

    DEFF Research Database (Denmark)

    Guldmann, Eva; Remmen, Arne

    The present report concerns the practical process of developing initiatives based on the circular economy in eight Danish companies. The report outlines how the process of integrating the circular economy was approached in each of the participating companies during 2014 and 2015 and what came out...

  4. Vibration mixer

    Energy Technology Data Exchange (ETDEWEB)

    Alekhin, S.A.; Chernov, V.S.; Denisenko, V.V.; Gorodnyanskiy, I.F.; Prokopov, L.I.; Tikhonov, Yu.P.

    1983-01-01

    The vibration mixer is proposed which contains a housing, vibration drive with rod installed in the upper part of the mixing mechanism made in the form of a hollow shaft with blades. In order to improve intensity of mixing and dispersion of the mud, the shaft with the blades is arranged on the rod of the vibrator and is equipped with a cam coupling whose drive disc is attached to the vibration rod. The rod is made helical, while the drive disc of the cam coupling is attached to the helical surface of the rod. In addition, the vibration mixer is equipped with perforated discs installed on the ends of the rods.

  5. Radial vibration and ultrasonic field of a long tubular ultrasonic radiator.

    Science.gov (United States)

    Shuyu, Lin; Zhiqiang, Fu; Xiaoli, Zhang; Yong, Wang; Jing, Hu

    2013-09-01

    The radial vibration of a metal long circular tube is studied analytically and its electro-mechanical equivalent circuit is obtained. Based on the equivalent circuit, the radial resonance frequency equation is derived. The theoretical relationship between the radial resonance frequency and the geometrical dimensions is studied. Finite element method is used to simulate the radial vibration and the radiated ultrasonic field and the results are compared with those from the analytical method. It is concluded that the radial resonance frequency for a solid metal rod is larger than that for a metal tube with the same outer radius. The radial resonance frequencies from the analytical method are in good agreement with those from the numerical method. Based on the acoustic field analysis, it is concluded that the long metal tube with small wall thickness is superior to that with large wall thickness in producing radial vibration and ultrasonic radiation. Therefore, it is expected to be used as an effective radial ultrasonic radiator in ultrasonic sewage treatment, ultrasonic antiscale and descaling and other ultrasonic liquid handling applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Antennas on circular cylinders

    DEFF Research Database (Denmark)

    Knudsen, H. L.

    1959-01-01

    On the basis of the results obtained by Silver and Saunders [4] for the field radiated from an arbitrary slot in a perfectly conducting circular cylinder, expressions have been derived for the field radiated by a narrow helical slot, with an arbitrary aperture field distribution, in a circular...... antenna in a circular cylinder. By a procedure similar to the one used by Silver and Saunders, expressions have been derived for the field radiated from an arbitrary surface current distribution on a cylinder surface coaxial with a perfectly conducting cylinder. The cases where the space between the two...

  7. Design guide for calculating fluid damping for circular cylindrical structures

    International Nuclear Information System (INIS)

    Chen, S.S.

    1983-06-01

    Fluid damping plays an important role for structures submerged in fluid, subjected to flow, or conveying fluid. This design guide presents a summary of calculational procedures and design data for fluid damping for circular cylinders vibrating in quiescent fluid, crossflow, and parallel flow

  8. Digitalizing the Circular Economy

    Science.gov (United States)

    Reuter, Markus A.

    2016-12-01

    Metallurgy is a key enabler of a circular economy (CE), its digitalization is the metallurgical Internet of Things (m-IoT). In short: Metallurgy is at the heart of a CE, as metals all have strong intrinsic recycling potentials. Process metallurgy, as a key enabler for a CE, will help much to deliver its goals. The first-principles models of process engineering help quantify the resource efficiency (RE) of the CE system, connecting all stakeholders via digitalization. This provides well-argued and first-principles environmental information to empower a tax paying consumer society, policy, legislators, and environmentalists. It provides the details of capital expenditure and operational expenditure estimates. Through this path, the opportunities and limits of a CE, recycling, and its technology can be estimated. The true boundaries of sustainability can be determined in addition to the techno-economic evaluation of RE. The integration of metallurgical reactor technology and systems digitally, not only on one site but linking different sites globally via hardware, is the basis for describing CE systems as dynamic feedback control loops, i.e., the m-IoT. It is the linkage of the global carrier metallurgical processing system infrastructure that maximizes the recovery of all minor and technology elements in its associated refining metallurgical infrastructure. This will be illustrated through the following: (1) System optimization models for multimetal metallurgical processing. These map large-scale m-IoT systems linked to computer-aided design tools of the original equipment manufacturers and then establish a recycling index through the quantification of RE. (2) Reactor optimization and industrial system solutions to realize the "CE (within a) Corporation—CEC," realizing the CE of society. (3) Real-time measurement of ore and scrap properties in intelligent plant structures, linked to the modeling, simulation, and optimization of industrial extractive process

  9. Surface-enhanced vibrational spectroscopy of B vitamins: what is the effect of SERS-active metals used?

    Science.gov (United States)

    Kokaislová, A; Matějka, P

    2012-05-01

    Surface-enhanced Raman scattering (SERS) spectroscopy and surface-enhanced infrared absorption (SEIRA) spectroscopy are analytical tools suitable for the detection of small amounts of various analytes adsorbed on metal surfaces. During recent years, these two spectroscopic methods have become increasingly important in the investigation of adsorption of biomolecules and pharmaceuticals on nanostructured metal surfaces. In this work, the adsorption of B-group vitamins pyridoxine, nicotinic acid, folic acid and riboflavin at electrochemically prepared gold and silver substrates was investigated using Fourier transform SERS spectroscopy at an excitation wavelength of 1,064 nm. Gold and silver substrates were prepared by cathodic reduction on massive platinum targets. In the case of gold substrates, oxidation-reduction cycles were applied to increase the enhancement factor of the gold surface. The SERS spectra of riboflavin, nicotinic acid, folic acid and pyridoxine adsorbed on silver substrates differ significantly from SERS spectra of these B-group vitamins adsorbed on gold substrates. The analysis of near-infrared-excited SERS spectra reveals that each of B-group vitamin investigated interacts with the gold surface via a different mechanism of adsorption to that with the silver surface. In the case of riboflavin adsorbed on silver substrate, the interpretation of surface-enhanced infrared absorption (SEIRA) spectra was also helpful in investigation of the adsorption mechanism.

  10. Linear response properties required to simulate vibrational spectra of biomolecules in various media: (R)-phenyloxirane (A comparative theoretical and spectroscopic vibrational study)

    DEFF Research Database (Denmark)

    Jalkanen, Karl J.; Jürgensen, Vibeke Würtz; Degtyarenko, I.M.

    2005-01-01

    We here present a combined VA, VCD, Raman and ROA vibrational study of phenyloxirane. We have simulated the vibrational absorption (VA), also called IR, vibrational circular dichroism (VCD), Raman scattering and Raman optical activity (ROA) intensities utilizing the density functional theory (DFT...

  11. Combined effects of ultrasonic vibration and manganese on Fe-containing inter-metallic compounds and mechanical properties of Al-17Si alloy with 3wt.%Fe

    Directory of Open Access Journals (Sweden)

    Lin Chong

    2013-05-01

    Full Text Available The research studied the combined effects of ultrasonic vibration (USV and manganese on the Fe-containing inter-metallic compounds and mechanical properties of Al-17Si-3Fe-2Cu-1Ni (wt.% alloys. The results showed that, without USV, the alloys with 0.4wt.% Mn or 0.8wt.% Mn both contain a large amount of coarse plate-like δ-Al4(Fe,MnSi2 phase and long needle-like β-Al5(Fe,MnSi phase. When the Mn content changes from 0.4wt.% to 0.8wt.% in the alloys, the amount and the length of needle-like β-Al5(Fe,MnSi phase decrease and the plate-like δ-Al4(Fe,MnSi2 phase becomes much coarser. After USV treatment, the Fe-containing compounds in the alloys are refined and exist mainly as δ-Al4(Fe,MnSi2 particles with an average grain size of about 20 μm, and only a small amount of β-Al5(Fe,MnSi phase remains. With USV treatment, the ultimate tensile strengths (UTS of the alloys containing 0.4wt.%Mn and 0.8wt.%Mn at room temperature are 253 MPa and 262 MPa, respectively, and the ultimate tensile strengths at 350 °C are 129 MPa and 135 MPa, respectively. It is considered that the modified morphology and uniform distribution of the Fe-containing inter-metallic compounds, which are caused by the USV process, are the main reasons for the increase in the tensile strength of these two alloys.

  12. Application of the backscattering of an atomic beam of thermal energy to the study of the vibrational properties of metal surfaces

    International Nuclear Information System (INIS)

    Lapujoulade, J.; Lejay, Y.

    1975-01-01

    Vibrational properties of metal surfaces (surface phonons, surface Debye temperatures) are less known than bulk ones since common investigation methods (neutron, X-rays) are not sensitive to surface properties. A study of the backscattering of an atomic beam may give surface specific informations. The backscattering of noble gas (He, Ne, Ar) from a clean copper single crystal ((100) face) was experimentally studied. The experimental set-up allows to measure the space repartition well as the velocity distribution of the scattered atoms. If the collisions is purely elastic an analysis of the thermal dependence of the specular peak by means of the Debye Waller formula will give the mean square displacements of surface atoms. It is shown however that this simple case is not fulfilled with helium in ordinary beam or solid temperatures. If the collision is inelastic, but dominated by single phonon transfers (as it seems to be the case for helium) information should to get about the phonon dispersion relation of surface atoms. When many-phonon collision occur (Ne and Ar) the analysis is more difficult. A comparison of the experimental result with an approximate calculation of G. Armand is given [fr

  13. The molecular, electronic structures and vibrational spectra of metal-free, N,N'-dideuterio and magnesium tetra-2,3-pyridino-porphyrazines: Density functional calculations.

    Science.gov (United States)

    Liu, Zhongqiang; Zhang, Xianxi; Zhang, Yuexing; Li, Renjie; Jiang, Jianzhuang

    2006-10-01

    A theoretical investigation of the fully optimized geometries and electronic structures of the metal-free (TPdPzH(2)), N,N'-dideuterio (TPdPzD(2)), and magnesium (TPdPzMg) tetra-2,3-pyridino-porphyrazine has been conducted based on density functional theory. The optimized geometries at density functional theory level for these compounds are reported here for the first time. A comparison between the different molecules for the geometry, molecular orbital, and atomic charge is made. The substituent effect of the N atoms on the molecular structures of these compounds is discussed. The IR and Raman spectra for these three compounds have also been calculated at density functional B3LYP level using the 6-31G(d) basis set. Detailed assignments of the NH, NM, and pyridine ring vibrational bands in the IR and Raman spectra have been made based on assistance of animated pictures. The simulated IR spectra of TPdPzH(2) are compared with the experimental absorption spectra, and very good consistency has been found. The isotope effect on the IR and Raman spectra is also discussed.

  14. Ship Vibrations

    DEFF Research Database (Denmark)

    Sørensen, Herman

    1997-01-01

    Methods for calculating natural frequencies for ship hulls and for plates and panels.Evaluation of the risk for inconvenient vibrations on board......Methods for calculating natural frequencies for ship hulls and for plates and panels.Evaluation of the risk for inconvenient vibrations on board...

  15. Building a Circular Future

    DEFF Research Database (Denmark)

    Merrild, Heidi

    2016-01-01

    Natural resources are scarce and construction accounts for 40 percent of the material and energy consumption in Europe. This means that a switch to a circular future is necessary. ’Building a Circular Future’ maps out where we are, where we are going, and what is needed for this conversion to take...... on the project’s strategies. The financial result is a profit of DKK 35 million on the structure alone in the demolition of a building built for the cost of DKK 860 million. The total potential for the whole building, calculated in projected material prices, is estimated to be up to 16% of the total construction...... of the circular strategies is not only in the future. Increased flexibility, optimized operation and maintenance, as well as a healthier building, is low-hanging fruit that can be harvested today. The project’s principles can be implemented in industrialized construction in a large scale today. That is proven...

  16. Transposable elements and circular DNAs

    KAUST Repository

    Mourier, Tobias

    2016-09-26

    Circular DNAs are extra-chromosomal fragments that become circularized by genomic recombination events. We have recently shown that yeast LTR elements generate circular DNAs through recombination events between their flanking long terminal repeats (LTRs). Similarly, circular DNAs can be generated by recombination between LTRs residing at different genomic loci, in which case the circular DNA will contain the intervening sequence. In yeast, this can result in gene copy number variations when circles contain genes and origins of replication. Here, I speculate on the potential and implications of circular DNAs generated through recombination between human transposable elements.

  17. Transposable elements and circular DNAs

    KAUST Repository

    Mourier, Tobias

    2016-01-01

    Circular DNAs are extra-chromosomal fragments that become circularized by genomic recombination events. We have recently shown that yeast LTR elements generate circular DNAs through recombination events between their flanking long terminal repeats (LTRs). Similarly, circular DNAs can be generated by recombination between LTRs residing at different genomic loci, in which case the circular DNA will contain the intervening sequence. In yeast, this can result in gene copy number variations when circles contain genes and origins of replication. Here, I speculate on the potential and implications of circular DNAs generated through recombination between human transposable elements.

  18. Circular arc structures

    KAUST Repository

    Bo, Pengbo; Pottmann, Helmut; Kilian, Martin; Wang, Wen Ping; Wallner, Johannes

    2011-01-01

    and connecting elements as well as repetition of costly parts. This paper proposes so-called circular arc structures as a means to faithfully realize freeform designs without giving up smooth appearance. In contrast to non-smooth meshes with straight edges where

  19. Wiimote Experiments: Circular Motion

    Science.gov (United States)

    Kouh, Minjoon; Holz, Danielle; Kawam, Alae; Lamont, Mary

    2013-01-01

    The advent of new sensor technologies can provide new ways of exploring fundamental physics. In this paper, we show how a Wiimote, which is a handheld remote controller for the Nintendo Wii video game system with an accelerometer, can be used to study the dynamics of circular motion with a very simple setup such as an old record player or a…

  20. Administrative circular No. 12

    CERN Document Server

    HR Department

    2006-01-01

    On the recommendation of the Standing Concertation Committee, the Director-General has approved the amounts used for the reimbursements mentioned in Administrative Circular No. 12 as follows: The figures, effective from 1 September 2006, are: Paragraph 8a: 17 Swiss francs Paragraph 9a: 682 Swiss francs Paragraph 9b: 34 Swiss francs Human Resources Department Tel. 79257/72862

  1. Radical Circular Economy

    NARCIS (Netherlands)

    Prins, M.; Mohammadi, S.; Slob, N.

    2015-01-01

    Recently the Circular Economy (CE) concept has gained momentum in the Netherlands, propounding that environmental impact reduction can provide a significant positive economical impulse. The government, larger parts of the industry as a whole, as well as the construction industry, has warmly received

  2. Urban vibrations

    DEFF Research Database (Denmark)

    Morrison, Ann; Knudsen, L.; Andersen, Hans Jørgen

    2012-01-01

    In   this   paper   we   describe   a   field   study   conducted   with   a   wearable   vibration   belt   where   we   test   to   determine   the   vibration   intensity   sensitivity   ranges   on   a   large   diverse   group   of   participants   with   evenly   distributed  ages  and...

  3. Modified circular velocity law

    Science.gov (United States)

    Djeghloul, Nazim

    2018-05-01

    A modified circular velocity law is presented for a test body orbiting around a spherically symmetric mass. This law exhibits a distance scale parameter and allows to recover both usual Newtonian behaviour for lower distances and a constant velocity limit at large scale. Application to the Galaxy predicts the known behaviour and also leads to a galactic mass in accordance with the measured visible stellar mass so that additional dark matter inside the Galaxy can be avoided. It is also shown that this circular velocity law can be embedded in a geometrical description of spacetime within the standard general relativity framework upon relaxing the usual asymptotic flatness condition. This formulation allows to redefine the introduced Newtonian scale limit in term of the central mass exclusively. Moreover, a satisfactory answer to the galactic escape speed problem can be provided indicating the possibility that one can also get rid of dark matter halo outside the Galaxy.

  4. Circular fringe projection profilometry.

    Science.gov (United States)

    Zhao, Hong; Zhang, Chunwei; Zhou, Changquan; Jiang, Kejian; Fang, Meiqi

    2016-11-01

    In this Letter, a novel three-dimensional (3D) measurement method, called the circular fringe projection profilometry (CFPP), is proposed. Similar to the conventional fringe projection profilometry, CFPP also requires fringe pattern projection and capture, phase demodulation, and phase unwrapping. However, it works with a totally different mechanism. CFPP recovers the height of a point by calculating its distance to the optical center of a projector along the optical axis. This distance is calculated with the aid of the divergence angle of a projected light ray and the distance between the measured point and the optical axis. The distance between the measured point and the optical axis is detected by a camera with telecentric lenses, while the divergence angle can be calculated from the phase of a captured circular fringe pattern. The validity of CFPP is confirmed by a set of experiments.

  5. Administrative Circular N° 12

    CERN Multimedia

    2003-01-01

    Following a recommendation by the Standing Concertation Committee, the Director-General has approved the amounts used for the reimbursements mentioned in Administrative Circular N° 12 as follows : The figures, effective from 1 September 2003, are : § 8a : 16.50 Swiss francs (previously 16.- Swiss francs) § 9a : 663 Swiss francs (previously 640.- Swiss francs) § 9b : 33 Swiss francs (previously 32.- Swiss francs) Human Resources Division Tel. 72862/74474

  6. Circular arc structures

    KAUST Repository

    Bo, Pengbo

    2011-07-01

    The most important guiding principle in computational methods for freeform architecture is the balance between cost efficiency on the one hand, and adherence to the design intent on the other. Key issues are the simplicity of supporting and connecting elements as well as repetition of costly parts. This paper proposes so-called circular arc structures as a means to faithfully realize freeform designs without giving up smooth appearance. In contrast to non-smooth meshes with straight edges where geometric complexity is concentrated in the nodes, we stay with smooth surfaces and rather distribute complexity in a uniform way by allowing edges in the shape of circular arcs. We are able to achieve the simplest possible shape of nodes without interfering with known panel optimization algorithms. We study remarkable special cases of circular arc structures which possess simple supporting elements or repetitive edges, we present the first global approximation method for principal patches, and we show an extension to volumetric structures for truly threedimensional designs. © 2011 ACM.

  7. Vibrating minds

    CERN Multimedia

    2009-01-01

    Ed Witten is one of the leading scientists in the field of string theory, the theory that describes elementary particles as vibrating strings. This week he leaves CERN after having spent a few months here on sabbatical. His wish is that the LHC will unveil supersymmetry.

  8. Vibrational spectroscopy

    Science.gov (United States)

    Umesh P. Agarwal; Rajai Atalla

    2010-01-01

    Vibrational spectroscopy is an important tool in modern chemistry. In the past two decades, thanks to significant improvements in instrumentation and the development of new interpretive tools, it has become increasingly important for studies of lignin. This chapter presents the three important instrumental methods-Raman spectroscopy, infrared (IR) spectroscopy, and...

  9. Circular RNAs in cancer

    DEFF Research Database (Denmark)

    Kristensen, L S; Hansen, T B; Venø, M T

    2018-01-01

    Circular RNA (circRNA) is a novel member of the noncoding cancer genome with distinct properties and diverse cellular functions, which is being explored at a steadily increasing pace. The list of endogenous circRNAs involved in cancer continues to grow; however, the functional relevance of the vast...... for circRNA cancer research and current caveats, which must be addressed to facilitate the translation of basic circRNA research into clinical use.Oncogene advance online publication, 9 October 2017; doi:10.1038/onc.2017.361....

  10. Circularly polarized antennas

    CERN Document Server

    Gao, Steven; Zhu, Fuguo

    2013-01-01

    This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arrays In this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Adva

  11. Neural-network analysis of the vibrational spectra of N-acetyl L-alanyl N '-methyl amide conformational states

    DEFF Research Database (Denmark)

    Bohr, Henrik; Frimand, Kenneth; Jalkanen, Karl J.

    2001-01-01

    Density-functional theory (DFT) calculations utilizing the Becke 3LYP hybrid functional have been carried out for N-acetyl L-alanine N'-methylamide and examined with respect to the effect of water on the structure, the vibrational frequencies, vibrational absorption (VA), vibrational circular dic...

  12. Circular states of atomic hydrogen

    International Nuclear Information System (INIS)

    Lutwak, R.; Holley, J.; Chang, P.P.; Paine, S.; Kleppner, D.; Ducas, T.

    1997-01-01

    We describe the creation of circular states of hydrogen by adiabatic transfer of a Rydberg state in crossed electric and magnetic fields, and also by adiabatic passage in a rotating microwave field. The latter method permits rapid switching between the two circular states of a given n manifold. The two methods are demonstrated experimentally, and results are presented of an analysis of the field ionization properties of the circular states. An application for the circular states is illustrated by millimeter-wave resonance in hydrogen of the n=29→n=30 transition. copyright 1997 The American Physical Society

  13. Conformational effects in photoelectron circular dichroism

    Science.gov (United States)

    Turchini, S.

    2017-12-01

    Photoelectron circular dichroism (PECD) is a novel type of spectroscopy, which presents surprising sensitivity to conformational effects in chiral systems. While classical photoelectron spectroscopy mainly responds to conformational effects in terms of energy level shifts, PECD provides a rich and detailed response to tiny changes in electronic and structural properties by means of the intensity dispersion of the circular dichroism as a function of photoelectron kinetic energy. In this work, the basics of PECD will be outlined, emphasizing the role of interference from the l,l+/- 1 outgoing partial wave of the photoelectron in the PECD transition matrix element, which is responsible for the extreme sensitivity to conformational effects. Examples using molecular systems and interfaces will shed light on the powerful application of PECD to classical conformational effects such as group substitution, isomerism, conformer population and clustering. Moreover, the PECD results will be reported in challenging new fields where conformations play a key role, such as vibrational effects, transient chirality and time- resolved experiments. To date, PECD has mostly been based on synchrotron radiation facilities, but it also has a future as a table-top lab experiment by means of multiphoton ionization. An important application of PECD as an analytical tool will be reported. The aim of this review is to illustrate that in PECD, the presence of conformational effects is essential for understanding a wide range of effects from a new perspective, making it different from classical spectroscopy.

  14. The Circular Camera Movement

    DEFF Research Database (Denmark)

    Hansen, Lennard Højbjerg

    2014-01-01

    It has been an accepted precept in film theory that specific stylistic features do not express specific content. Nevertheless, it is possible to find many examples in the history of film in which stylistic features do express specific content: for instance, the circular camera movement is used...... repeatedly to convey the feeling of a man and a woman falling in love. This raises the question of why producers and directors choose certain stylistic features to narrate certain categories of content. Through the analysis of several short film and TV clips, this article explores whether...... or not there are perceptual aspects related to specific stylistic features that enable them to be used for delimited narrational purposes. The article further attempts to reopen this particular stylistic debate by exploring the embodied aspects of visual perception in relation to specific stylistic features...

  15. Operational circular No. 1 (Rev. 1) – Operational circulars

    CERN Multimedia

    HR Department

    2011-01-01

    Operational Circular No. 1 (Rev. 1) is applicable to members of the personnel and other persons concerned. Operational Circular No. 1 (Rev. 1) entitled "Operational circulars", approved following discussion at the Standing Concertation Committee meeting on 4 May 2011, is available on the intranet site of the Human Resources Department: https://hr-docs.web.cern.ch/hr-docs/opcirc/opcirc.asp It cancels and replaces Operational Circular No. 1 entitled "Operational Circulars” of December 1996. This new version clarifies, in particular, that operational circulars do not necessarily arise from the Staff Rules and Regulations, and the functional titles have been updated to bring them into line with the current CERN organigram. Department Head Office  

  16. Circular defects detection in welded joints using circular hough transform

    International Nuclear Information System (INIS)

    Hafizal Yazid; Mohd Harun; Shukri Mohd; Abdul Aziz Mohamed; Shaharudin Sayuti; Muhamad Daud

    2007-01-01

    Conventional radiography is one of the common non-destructive testing which employs manual image interpretation. The interpretation is very subjective and depends much on the inspector experience and working conditions. It is therefore useful to have pattern recognition system in order to assist human interpreter in evaluating the quality of the radiograph sample, especially radiographic image of welded joint. This paper describes a system to detect circular discontinuities that is present in the joints. The system utilizes together 2 different algorithms, which is separability filter to identify the best object candidate and Circular Hough Transform to detect the present of circular shape. The result of the experiment shows a promising output in recognition of circular discontinuities in a radiographic image. This is based on 81.82-100% of radiography film with successful circular detection by using template movement of 10 pixels. (author)

  17. Symplectic methods in circular accelerators

    International Nuclear Information System (INIS)

    Forest, E.

    1994-01-01

    By now symplectic integration has been applied to many problems in classical mechanics. It is my conviction that the field of particle simulation in circular rings is ideally suited for the application of symplectic integration. In this paper, I present a short description symplectic tools in circular storage rings

  18. Circular induction accelerator for borehole logging

    International Nuclear Information System (INIS)

    Chen, F.K.; Bertozzi, W.; Corris, G.W.; Diamond, W.; Doucet, J.A.; Schweitzer, J.S.

    1992-01-01

    This patent describes a downhole logging sonde adapted to be moved through a borehole, a source of gamma rays in the sonde for irradiating earth formations traversed by the borehole, one or more gamma ray detectors for detecting gamma rays scattered back to the sonde from the irradiated earth formations, and means for transmitting signals representative of the detected gamma rays to the earth's surface for processing. This patent describes improvement in the gamma ray source comprises a magnetic induction particle accelerator, including: a magnetic circuit having a field magnet, generally circular opposed pole pieces, and a core magnet metal ions from the group consisting of Mn, Zn and Ni; an excitation circuit including a field coil surrounding the field magnet and the core magnet and a core coil surrounding the central axially leg of the core magnet; an annular acceleration chamber interposed between the pole pieces; means for applying time-varying acceleration voltage pulses across the primary excitation circuit; means for injecting charged particles into orbit within the acceleration chamber; means for compressing the particle orbits to trap particles within generally circular orbits within the acceleration chamber; means for generating a particle accelerating magnetic flux in the magnetic circuit; and means for ejecting charged particles from the generally circular orbits and into contact with a target to produce gamma ray photons

  19. Design for Circular Behaviour: Considering Users in a Circular Economy

    Directory of Open Access Journals (Sweden)

    Thomas Wastling

    2018-05-01

    Full Text Available In a linear economy, a product is manufactured and sold to a customer. Then, little concern is given to what the user actually does with it when they have it. However, in a circular economy where the aim is to circulate products at their highest level of value, the customer’s behaviour can become an important part of the system. Circular design strategies have tended to focus on the physical aspects of a product (e.g., disassembly, material selection, but the design of products and services can also have an influence on user behaviour and, to date, this aspect of circular design has not been fully explored. This project aims to define what key user behaviours are required for circular business models to work and to outline how design can enable these ‘circular behaviours’. This research project consists of a literature review, case study analysis and expert interviews with practitioners. A theoretical framework for designing products and services to encourage circular behaviour is developed. This work provides an initial step towards a better understanding of the user’s role in the transition to a circular economy as well as a preliminary model for how design for behaviour change strategies could be implemented in this context.

  20. Towards Future Circular Colliders

    CERN Document Server

    AUTHOR|(CDS)2108454; Zimmermann, Frank

    2016-01-01

    The Large Hadron Collider (LHC) at CERN presently provides proton-proton collisions at a centre-of-mass (c.m.) energy of 13 TeV. The LHC design was started more than 30 years ago, and its physics programme will extend through the second half of the 2030’s. The global Future Circular Collider (FCC) study is now preparing for a post-LHC project. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh) in a new ∼100 km tunnel. It also includes the design of a high-luminosity electron-positron collider (FCC-ee) as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on $Nb_3Sn$ superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton c...

  1. Future Circular Colliders

    CERN Document Server

    AUTHOR|(CDS)2108454; Zimmermann, Frank

    2016-01-01

    In response to a request from the 2013 Update of the European Strategy for Particle Physics, the global Future Circular Collider (FCC) study is preparing the foundation for a next-generation large-scale accelerator infrastructure in the heart of Europe. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh), to be accommodated in a new ∼100 km tunnel near Geneva. It also includes the design of a high-luminosity electron-positron collider (FCC-ee), which could be installed in the same tunnel as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detector, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on Nb$_{3}$Sn superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton collider. The int...

  2. Future Circular Colliders

    CERN Document Server

    AUTHOR|(CDS)2108454; Zimmermann, Frank

    2016-01-01

    In response to a request from the 2013 Update of the European Strategy for Particle Physics, the global Future Circular Collider (FCC) study is preparing the foundation for a next-generation large-scale accelerator infrastructure in the heart of Europe. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh), to be accommodated in a new ∼100 km tunnel near Geneva. It also includes the design of a high-luminosity electron-positron collider (FCC-ee), which could be installed in the same tunnel as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on Nb$_{3}$Sn superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton collider. The in...

  3. Nuclear spin circular dichroism

    International Nuclear Information System (INIS)

    Vaara, Juha; Rizzo, Antonio; Kauczor, Joanna; Norman, Patrick; Coriani, Sonia

    2014-01-01

    Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra

  4. Experimental Study on Piezoelectric Energy Harvesting from Vortex-Induced Vibrations and Wake-Induced Vibrations

    Directory of Open Access Journals (Sweden)

    Min Zhang

    2016-01-01

    Full Text Available A rigid circular cylinder with two piezoelectric beams attached on has been tested through vortex-induced vibrations (VIV and wake-induced vibrations (WIV by installing a big cylinder fixed upstream, in order to study the influence of the different flow-induced vibrations (FIV types. The VIV test shows that the output voltage increases with the increases of load resistance; an optimal load resistance exists for the maximum output power. The WIV test shows that the vibration of the small cylinder is controlled by the vortex frequency of the large one. There is an optimal gap of the cylinders that can obtain the maximum output voltage and power. For a same energy harvesting device, WIV has higher power generation capacity; then the piezoelectric output characteristics can be effectively improved.

  5. Evaluation of Massey Ferguson Model 165 Tractor Drivers exposed to whole-body vibration

    Directory of Open Access Journals (Sweden)

    P. Nassiri

    2013-12-01

    Conclusion: This study shows that the need to provide intervention , controlling and managing measures to eliminate or reduce exposure to whole body vibration among tractor drivers its necessary. And, preventing main disorder Including musculoskeletal disorders, discomfort and early fatigue is of circular importance. More studies are also necessary to identify the sources of vibration among various of tractors.

  6. Cyanide bridged hetero-metallic polymeric complexes: Syntheses, vibrational spectra, thermal analyses and crystal structures of complexes [M(1,2-dmi)2Ni(μ-CN)4]n (M = Zn(II) and Cd(II))

    Science.gov (United States)

    Kürkçüoğlu, Güneş Süheyla; Sayın, Elvan; Şahin, Onur

    2015-12-01

    Two cyanide bridged hetero-metallic complexes of general formula, [M(1,2-dmi)2Ni(μ-CN)4]n (1,2-dmi = 1,2-dimethylimidazole and M = Zn(II) or Cd(II)) have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal analyses and elemental analyses. The crystallographic analyses reveal that the complexes, [Zn(1,2-dmi)2Ni(μ-CN)4] (1) and [Cd(1,2-dmi)2Ni(μ-CN)4] (2), have polymeric 2D networks. In the complexes, four cyanide groups of [Ni(CN)4]2- coordinated to the adjacent M(II) ions and distorted octahedral geometries of complexes are completed by two nitrogen atoms of trans 1,2-dmi ligands. The structures of 1 and 2 are similar and linked via intermolecular hydrogen bonding, C-H⋯Ni interactions to give rise to 3D networks. Vibration assignments are given for all the observed bands and the spectral features also supported to the crystal structures of heteronuclear complexes. The FT-IR and Raman spectra of the complexes are very much consistent with the structural data presented.

  7. Hot Ground Vibration Tests

    Data.gov (United States)

    National Aeronautics and Space Administration — Ground vibration tests or modal surveys are routinely conducted to support flutter analysis for subsonic and supersonic vehicles. However, vibration testing...

  8. Pressure dependence of the elastic constants and vibrational anharmonicity of Pd sub 3 sub 9 Ni sub 1 sub 0 Cu sub 3 sub 0 P sub 2 sub 1 bulk metallic glass

    CERN Document Server

    Wang Li; Sun, L L; Wang, W H; Wang, W K

    2003-01-01

    The pressure dependence of the acoustic velocities of a Pd sub 3 sub 9 Ni sub 1 sub 0 Cu sub 3 sub 0 P sub 2 sub 1 bulk metallic glass have been investigated up to 0.5 GPa at room temperature with the pulse echo overlap method. Two independent second-order elastic coefficients C sub 1 sub 1 and C sub 4 sub 4 and their pressure derivatives are yielded. The vibrational anharmonicity is shown by calculating both the acoustic mode Grueneisen parameters in the long-wavelength limit and the thermal Grueneisen parameter, and this result is compared with that for the Pd sub 4 sub 0 Ni sub 4 sub 0 P sub 2 sub 0 bulk glass.

  9. Towards future circular colliders

    Science.gov (United States)

    Benedikt, Michael; Zimmermann, Frank

    2016-09-01

    The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) presently provides proton-proton collisions at a center-of-mass (c.m.) energy of 13 TeV. The LHC design was started more than 30 years ago, and its physics program will extend through the second half of the 2030's. The global Future Circular Collider (FCC) study is now preparing for a post-LHC project. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh) in a new ˜100 km tunnel. It also includes the design of a high-luminosity electron-positron collider (FCCee) as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on Nb3 S n superconductor, for the FCC-hh hadron collider, and a highly-efficient superconducting radiofrequency system for the FCC-ee lepton collider. Following the FCC concept, the Institute of High Energy Physics (IHEP) in Beijing has initiated a parallel design study for an e + e - Higgs factory in China (CEPC), which is to be succeeded by a high-energy hadron collider (SPPC). At present a tunnel circumference of 54 km and a hadron collider c.m. energy of about 70 TeV are being considered. After a brief look at the LHC, this article reports the motivation and the present status of the FCC study, some of the primary design challenges and R&D subjects, as well as the emerging global collaboration.

  10. Circular polarization observed in bioluminescence

    NARCIS (Netherlands)

    Wynberg, H.; Meijer, E.W.; Hummelen, J.C.; Dekkers, H.P.J.M.; Schippers, P.H.; Carlson, A.D.

    1980-01-01

    The left and right lanterns of live larvae of the fireflies Photuris lucicrescens and P. versicolor emitted circularly polarized light of opposite sense. A possible mechanism is discussed. [on SciFinder (R)

  11. Structural dynamics and vibration 1995. PD-Volume 70

    International Nuclear Information System (INIS)

    Ovunc, B.A.; Esat, I.I.; Sabir, A.B.; Karadag, V.

    1995-01-01

    The themes of this symposium focused on: dynamic responses to temperature cycles and wind excitation; the influence of the hydraulic feedback on stability; structural reliability; vibratory stress relief; fault detection by signal processing; dynamic contact in mechanisms; vibration of thick flexible mechanisms; higher order mechanisms in flexible mechanisms; natural circular frequencies by finite element method; elastic buckling, stability, and vibration of linear and nonlinear structures; buckling of stiffened plates and rings; mixed variable optimization; vibration optimization; and optimization in a constrained space. Separate abstracts were prepared for 20 papers in this book

  12. Theory of vibration protection

    CERN Document Server

    Karnovsky, Igor A

    2016-01-01

    This text is an advancement of the theory of vibration protection of mechanical systems with lumped and distributed parameters. The book offers various concepts and methods of solving vibration protection problems, discusses the advantages and disadvantages of different methods, and the fields of their effective applications. Fundamental approaches of vibration protection, which are considered in this book, are the passive, parametric and optimal active vibration protection. The passive vibration protection is based on vibration isolation, vibration damping and dynamic absorbers. Parametric vibration protection theory is based on the Shchipanov-Luzin invariance principle. Optimal active vibration protection theory is based on the Pontryagin principle and the Krein moment method. The book also contains special topics such as suppression of vibrations at the source of their occurrence and the harmful influence of vibrations on humans. Numerous examples, which illustrate the theoretical ideas of each chapter, ar...

  13. A new method for evaluating the conformations and normal modes of macromolecule vibrations with a reduced force field. 2. Application to nonplanar distorted metal porphyrins

    Energy Technology Data Exchange (ETDEWEB)

    Unger, E.; Beck, M.; Lipski, R.J.; Dreybrodt, W.; Medforth, C.J.; Smith, K.M.; Schweitzer-Stenner, R.

    1999-11-11

    The authors have developed a novel method for molecular mechanics calculations and normal-mode analysis. It is based on symmetry of local units that constitutes the given molecule. Compared with general valence force field calculations, the number of free parameters is reduced by 40--80% in the procedure. It was found to reproduce very well the vibrational frequencies and mode compositions of aromatic compounds and porphyrins, as shown by comparison with DFT calculations. A slightly altered force field obtained from Ni(II) porphin was then used to calculate the structure and the normal modes of several meso-substituted Ni(II) porphyrins which are known to be subject to significant ruffling and/or saddling distortions. This method satisfactorily reproduces their nonplanar structure and Raman band frequencies in the natural abundance and isotopic derivative spectra. The polarization properties of bands from out-of-plane modes are in accordance with the predicted nonplanar distortions. Moreover, some of the modes below 800 cm{sup {minus}1} which appear intense in the Raman spectra contain considerable contributions from both in-plane and out-of-plane vibrations, so that the conventional mode assignments become questionable. The authors also demonstrate that the intensity and polarization of some low-frequency Raman bands can be used as a (quantitative) marker to elucidate type and magnitude of out-of-plane distortions. These were recently shown to affect heme groups of hemoglobin, myoglobin, and, in particular, of cytochrome c.

  14. Hydroelastic Oscillations of a Circular Plate, Resting on Winkler Foundation

    Science.gov (United States)

    Kondratov, D. V.; Mogilevich, L. I.; Popov, V. S.; Popova, A. A.

    2018-01-01

    The forced hydroelastic oscillations of a circular plate resting on elastic foundation are investigated. The oscillations are caused by a stamp vibration under interaction with a plate through a thin layer of viscous incompressible liquid. The axis-symmetric problem for the regime of the steady-state harmonic oscillations is considered. On the basis of hydroelasticity problem solution the laws of plate deflection and pressure in the liquid are found. The functions of the amplitudes deflection distribution and liquid pressure along the plate are constructed. The presented mathematical model provides for investigating viscous liquid layer interaction dynamics with a circular plate resting on an elastic foundation. The above-mentioned model makes it possible to define the plate oscillations resonance frequencies and the corresponding amplitudes of deflection and liquid pressure, as well.

  15. Simulation of 2D Waves in Circular Membrane Using Excel Spreadsheet with Visual Basic for Teaching Activity

    Science.gov (United States)

    Eso, R.; Safiuddin, L. O.; Agusu, L.; Arfa, L. M. R. F.

    2018-04-01

    We propose a teaching instrument demonstrating the circular membrane waves using the excel interactive spreadsheets with the Visual Basic for Application (VBA) programming. It is based on the analytic solution of circular membrane waves involving Bessel function. The vibration modes and frequencies are determined by using Bessel approximation and initial conditions. The 3D perspective based on the spreadsheets functions and facilities has been explored to show the 3D moving objects in transitional or rotational processes. This instrument is very useful both in teaching activity and learning process of wave physics. Visualizing of the vibration of waves in the circular membrane which is showing a very clear manner of m and n vibration modes of the wave in a certain frequency has been compared and matched to the experimental result using resonance method. The peak of deflection varies in time if the initial condition was working and have the same pattern with matlab simulation in zero initial velocity

  16. Generalized viscothermoelasticity theory of dual-phase-lagging model for damping analysis in circular micro-plate resonators

    Science.gov (United States)

    Grover, D.; Seth, R. K.

    2018-05-01

    Analysis and numerical results are presented for the thermoelastic dissipation of a homogeneous isotropic, thermally conducting, Kelvin-Voigt type circular micro-plate based on Kirchhoff's Love plate theory utilizing generalized viscothermoelasticity theory of dual-phase-lagging model. The analytical expressions for thermoelastic damping of vibration and frequency shift are obtained for generalized dual-phase-lagging model and coupled viscothermoelastic plates. The scaled thermoelastic damping has been illustrated in case of circular plate and axisymmetric circular plate for fixed aspect ratio for clamped and simply supported boundary conditions. It is observed that the damping of vibrations significantly depend on time delay and mechanical relaxation times in addition to thermo-mechanical coupling in circular plate under resonance conditions and plate dimensions.

  17. Catalyzed hydrogenation of nitrogen and ethylene on metal (Fe, Pt) single crystal surfaces and effects of coadsorption: A sum frequency generation vibrational spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Westerberg, Staffan Per Gustav [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    High-pressure catalytic reactions and associated processes, such as adsorption have been studied on a molecular level on single crystal surfaces. Sum Frequency Generation (SFG) vibrational spectroscopy together with Auger Electron Spectroscopy (AES), Temperature Programmed Desorption (TPD) and Gas Chromatography (GC) were used to investigate the nature of species on catalytic surfaces and to measure the catalytic reaction rates. Special attention has been directed at studying high-pressure reactions and in particular, ammonia synthesis in order to identify reaction intermediates and the influence of adsorbates on the surface during reaction conditions. The adsorption of gases N2, H2, O2 and NH3 that play a role in ammonia synthesis have been studied on the Fe(111) crystal surface by sum frequency generation vibrational spectroscopy using an integrated Ultra-High Vacuum (UHV)/high-pressure system. SFG spectra are presented for the dissociation intermediates, NH2 (~3325 cm-1) and NH (~3235 cm-1) under high pressure of ammonia (200 Torr) on the clean Fe(111) surface. Addition of 0.5 Torr of oxygen to 200 Torr of ammonia does not significantly change the bonding of dissociation intermediates to the surface. However, it leads to a phase change of nearly 180° between the resonant and non-resonant second order non-linear susceptibility of the surface, demonstrated by the reversal of the SFG spectral features. Heating the surface in the presence of 200 Torr ammonia and 0.5 Torr oxygen reduces the oxygen coverage, which can be seen from the SFG spectra as another relative phase change of 180°. The reduction of the oxide is also supported by Auger electron spectroscopy. The result suggests that the phase change of the spectral features could serve as a sensitive indicator of the chemical environment of the adsorbates.

  18. Vibration of machine

    International Nuclear Information System (INIS)

    Kwak, Mun Gyu; Na, Sung Su; Baek, Gwang Hyeon; Song, Chul Gi; Han, Sang Bo

    2001-09-01

    This book deals with vibration of machine which gives descriptions of free vibration using SDOF system, forced vibration using SDOF system, vibration of multi-degree of freedom system like introduction and normal form, distribution system such as introduction, free vibration of bar and practice problem, approximate solution like lumped approximations and Raleigh's quotient, engineering by intuition and experience, real problem and experimental method such as technology of signal, fourier transform analysis, frequency analysis and sensor and actuator.

  19. Sound Power Minimization of Circular Plates Through Damping Layer Placement

    Science.gov (United States)

    Wodtke, H.-W.; Lamancusa, J. S.

    1998-09-01

    Damping layers, widely used for noise and vibration control of thin-walled structures, can be designed to provide an optimal trade-off between performance and weight which is of particular importance in the automotive and aircraft industry. The goal of the presented work is the minimization of sound power radiated from plates under broadband excitation by redistribution of unconstrained damping layers. The total radiated sound power is assumed to be represented by the sound power radiated at the structural resonances. Resonance tracking is performed by means of single-degree-of-freedom (SDOF)-approximations based on near-resonance responses and their frequency derivatives. Axisymmetric vibrations of circular plates under several boundary and forcing conditions are considered. Frequency dependent Young's modulus and loss factor of the damping material are taken into account. Vibration analysis is based on the finite element method (FEM) while acoustic radiation is treated by means of Rayleigh's integral formula. It is shown that, starting from a uniform damping layer distribution, substantial reduction in radiated sound power can be achieved through redistribution of the damping layers. Depending on the given situation, these reductions are not only due to amplitude reductions but also to changes in vibration shapes and frequencies.

  20. Enhanced vibration diagnostics using vibration signature analysis

    International Nuclear Information System (INIS)

    Ahmed, S.; Shehzad, K.; Zahoor, Y.; Mahmood, A.; Bibi, A.

    2001-01-01

    Symptoms will appear in equipment, as well as in human beings. when 'suffering from sickness. Symptoms of abnormality in equipment are vibration, noise, deformation, temperature, pressure, electric current, crack, wearing, leakage etc. these are called modes of failure. If the mode of failure is vibration then the vibration signature analysis can be effectively used in order to diagnose the machinery problems. Much valuable information is contained within these vibration 'Spectra' or 'Signatures' but is only of use if the analyst can unlock its 'Secrets'. This paper documents a vibration problem in the motor of a centrifugal pump (Type ETA). It focuses mainly on the roll of modern vibration monitoring system in problem analysis. The problem experienced was the motor unstability and noise due to high vibration. Using enhanced vibration signature data, the problem was analyzed. which suggested that the rotor eccentricity was the cause of excessive noise and vibration in the motor. In conclusion, advanced electronic monitoring and diagnostic systems provide powerful information for machine's condition assessment and problem analysis. Appropriate interpretation and use of this information is important for accurate and effective vibration analysis. (author)

  1. Stresses in Circular Plates with Rigid Elements

    Science.gov (United States)

    Velikanov, N. L.; Koryagin, S. I.; Sharkov, O. V.

    2018-05-01

    Calculations of residual stress fields are carried out by numerical and static methods, using the flat cross-section hypothesis. The failure of metal when exposed to residual stresses is, in most cases, brittle. The presence in the engineering structures of rigid elements often leads to the crack initiation and structure failure. This is due to the fact that rigid elements under the influence of external stresses are stress concentrators. In addition, if these elements are fixed by welding, the residual welding stresses can lead to an increase in stress concentration and, ultimately, to failure. The development of design schemes for such structures is a very urgent task for complex technical systems. To determine the stresses in a circular plate with a welded circular rigid insert under the influence of an external load, one can use the solution of the plane stress problem for annular plates in polar coordinates. The polar coordinates of the points are the polar radius and the polar angle, and the stress state is determined by normal radial stresses, tangential and shearing stresses. The use of the above mentioned design schemes, formulas, will allow more accurate determination of residual stresses in annular welded structures. This will help to establish the most likely directions of failure and take measures at the stages of designing, manufacturing and repairing engineering structures to prevent these failures. However, it must be taken into account that the external load, the presence of insulation can lead to a change in the residual stress field.

  2. Vibrational spectroscopy of proteins

    International Nuclear Information System (INIS)

    Schwaighofer, A.

    2013-01-01

    Two important steps for the development of a biosensor are the immobilization of the biological component (e.g. protein) on a surface and the enhancement of the signal to improve the sensitivity of detection. To address these subjects, the present work describes Fourier transform infrared (FTIR) investigations of several proteins bound to the surface of an attenuated total reflection (ATR) crystal. Furthermore, new nanostructured surfaces for signal enhancement were developed for use in FTIR microscopy. The mitochondrial redox-protein cytochrome c oxidase (CcO) was incorporated into a protein-tethered bilayer lipid membrane (ptBLM) on an ATR crystal featuring a roughened two-layer gold surface for signal enhancement. Electrochemical excitation by periodic potential pulses at different modulation frequencies was followed by time-resolved FTIR spectroscopy. Phase sensitive detection was used for deconvolution of the IR spectra into vibrational components. A model based on protonation-dependent chemical reaction kinetics could be fitted to the time evolution of IR bands attributed to several different redox centers of the CcO. Further investigations involved the odorant binding protein 14 (OBP14) of the honey bee (Apis mellifera), which was studied using ATR-FTIR spectroscopy and circular dichroism. OBP14 was found to be thermally stable up to 45 °C, thus permitting the potential application of this protein for the fabrication of biosensors. Thermal denaturation measurements showed that odorant binding increases the thermal stability of the OBP-odorant complex. In another project, plasmonic nanostructures were fabricated that enhance the absorbance in FTIR microscopy measurements. The nanostructures are composed of an array of round-shaped insulator and gold discs on top of a continuous gold layer. Enhancement factors of up to ⁓125 could be observed with self-assembled monolayers of dodecanethiol molecules immobilized on the gold surface (author) [de

  3. [Occupational standing vibration rate and vibrational diseases].

    Science.gov (United States)

    Karnaukh, N G; Vyshchipan, V F; Haumenko, B S

    2003-12-01

    Occupational standing vibration rate is proposed in evaluating a degree of impairment of an organism activity. It will allow more widely to introduce specification of quality and quantity in assessment of the development of vibrational disease. According out-patient and inpatient obtained data we have established criterial values of functional changes in accordance with accumulated occupational standing vibration rate. The nomogram was worked out for defining a risk of the development of vibrational disease in mine workers. This nomogram more objectively can help in diagnostics of the disease.

  4. Heterodyne Angle Deviation Interferometry in Vibration and Bubble Measurements

    OpenAIRE

    Ming-Hung Chiu; Jia-Ze Shen; Jian-Ming Huang

    2016-01-01

    We proposed heterodyne angle deviation interferometry (HADI) for angle deviation measurements. The phase shift of an angular sensor (which can be a metal film or a surface plasmon resonance (SPR) prism) is proportional to the deviation angle of the test beam. The method has been demonstrated in bubble and speaker’s vibration measurements in this paper. In the speaker’s vibration measurement, the voltage from the phase channel of a lock-in amplifier includes the vibration level and frequency. ...

  5. Identification of multiple modes of axisymmetric or circularly repetitive structures

    International Nuclear Information System (INIS)

    Kopff, P.

    1983-01-01

    The axisymmetric structures, or those composed with circularly repetitive elements, often display multiple modes, which are not easy to separate by modal identification of experimental responses. To be able to solve in situ some problems related to the vibrational behaviour of reactor vessels or other such huge structures, ELECTRICITY DE FRANCE developed a few years ago, experimental capabilities providing heavy harmonic driving forces, and elaborate data acquisition, signal processing and modal identification software, self-contained in an integrated mobile test facility. The modal analysis techniques we have developed with the LABORATOIRE DE MECANIQUE Appliquee of University of BESANCON (FRANCE) were especially suited for identification of multiple or separation of quasi-multiple modes, i.e. very close and strongly coupled resonances. Besides, the curve fitting methods involved, compute the same complex eigen-frequencies for all the vibration pick-ups, for better accuracy of the related eigen-vector components. Moreover, the latest extensions of these algorithms give us the means to deal with non-linear behaviour. The performances of these programs are drawn from some experimental results on axisymmetric or circularly repetitive structure, we tested in our laboratory to validate the computational hypothesis used in models for seismic responses of breeder reactor vessels. (orig.)

  6. Circular polarization observed in bioluminescence

    NARCIS (Netherlands)

    Wijnberg, Hans; Meijer, E.W.; Hummelen, J.C.; Dekkers, H.P.J.M.; Schippers, P.H.; Carlson, A.D.

    1980-01-01

    While investigating circular polarization in luminescence, and having found it in chemiluminescence, we have studied bioluminescence because it is such a widespread and dramatic natural phenomenon. We report here that left and right lanterns of live larvae of the fireflies, Photuris lucicrescens and

  7. 140 CIRCULAR INTERACTION BETWEEN LINGUISTIC ...

    African Journals Online (AJOL)

    economy. Although a country or administrative district should have one or more official languages for obvious reasons, Nelde (1991) proposes that the ... circular interaction between linguistic departments and language departments. Finding an answer to' Plato's abovementioned problem entails that as many languages as ...

  8. High intensity circular proton accelerators

    International Nuclear Information System (INIS)

    Craddock, M.K.

    1987-12-01

    Circular machines suitable for the acceleration of high intensity proton beams include cyclotrons, FFAG accelerators, and strong-focusing synchrotrons. This paper discusses considerations affecting the design of such machines for high intensity, especially space charge effects and the role of beam brightness in multistage accelerators. Current plans for building a new generation of high intensity 'kaon factories' are reviewed. 47 refs

  9. Portable vibration exciter

    Science.gov (United States)

    Beecher, L. C.; Williams, F. T.

    1970-01-01

    Gas-driven vibration exciter produces a sinusoidal excitation function controllable in frequency and in amplitude. It allows direct vibration testing of components under normal loads, removing the possibility of component damage due to high static pressure.

  10. Flow-induced vibration of helical coil compression springs

    International Nuclear Information System (INIS)

    Stokes, F.E.; King, R.A.

    1983-01-01

    Helical coil compression springs are used in some nuclear fuel assembly designs to maintain holddown and to accommodate thermal expansion. In the reactor environment, the springs are exposed to flowing water, elevated temperatures and pressures, and irradiation. Flow parallel to the longitudinal axis of the spring may excite the spring coils and cause vibration. The purpose of this investigation was to determine the flow-induced vibration (FIV) response characteristics of the helical coil compression springs. Experimental tests indicate that a helical coil spring responds like a single circular cylinder in cross-flow. Two FIV excitation mechanisms control spring vibration. Namely: 1) Turbulent Buffeting causes small amplitude vibration which increases as a function of velocity squared. 2) Vortex Shedding causes large amplitude vibration when the spring natural frequency and Strouhal frequency coincide. Several methods can be used to reduce or to prevent vortex shedding large amplitude vibrations. One method is compressing the spring to a coil pitch-to-diameter ratio of 2 thereby suppressing the vibration amplitude. Another involves modifying the spring geometry to alter its stiffness and frequency characteristics. These changes result in separation of the natural and Strouhal frequencies. With an understanding of how springs respond in the flowing water environment, the spring physical parameters can be designed to avoid large amplitude vibration. (orig.)

  11. Classification Trees and the Analysis of Helicopter Vibration Data

    National Research Council Canada - National Science Library

    Larson, Harold

    1997-01-01

    .... These systems monitor (and can record) various flight parameters, pilot conversations, engine exhaust debris, metallic chip detector levels in the lubrication system, rotor track and balance, as well as vibration levels at selected...

  12. Architectural Surfaces and Structures from Circular Arcs

    KAUST Repository

    Shi, Ling

    2013-01-01

    the most attention from geometry researchers. In this thesis, we aim to realize this process with simple geometric primitives, circular arcs. We investigate architectural surfaces and structures consisting of circular arcs. Our focus is lying on how

  13. Vibrations and Eigenvalues

    Indian Academy of Sciences (India)

    We make music by causing strings, membranes, or air columns to vibrate. Engineers design safe structures by control- ling vibrations. I will describe to you a very simple vibrating system and the mathematics needed to analyse it. The ideas were born in the work of Joseph-Louis Lagrange (1736–1813), and I begin by quot-.

  14. Nonlinear resonance ultrasonic vibrations in Czochralski-silicon wafers

    Science.gov (United States)

    Ostapenko, S.; Tarasov, I.

    2000-04-01

    A resonance effect of generation of subharmonic acoustic vibrations is observed in as-grown, oxidized, and epitaxial silicon wafers. Ultrasonic vibrations were generated into a standard 200 mm Czochralski-silicon (Cz-Si) wafer using a circular ultrasound transducer with major frequency of the radial vibrations at about 26 kHz. By tuning frequency (f) of the transducer within a resonance curve, we observed a generation of intense f/2 subharmonic acoustic mode assigned as a "whistle." The whistle mode has a threshold amplitude behavior and narrow frequency band. The whistle is attributed to a nonlinear acoustic vibration of a silicon plate. It is demonstrated that characteristics of the whistle mode are sensitive to internal stress and can be used for quality control and in-line diagnostics of oxidized and epitaxial Cz-Si wafers.

  15. 76 FR 60593 - Title VI; Proposed Circular

    Science.gov (United States)

    2011-09-29

    ..., several of them related to ambiguous language in the existing Circular. The proposed Circular reorganizes... regional entity, and inclusive of public and private entities. This term is used exclusively in Chapter IV... revisions to the Title VI Circular. The section that addresses the existing requirement for a Language...

  16. Circular Business: Collaborate and Circulate : a bookreview

    NARCIS (Netherlands)

    Timmermans, Ratna W.; Witjes, S.|info:eu-repo/dai/nl/381088200

    2016-01-01

    With their book, “Circular Business: Collaborate and Circulate”, Circular Collaboration, Amersfoort, ISBN: 978-90-824902-0-6, €35, Kraaijenhagen et al. (2016) give companies practical guidance on their contribution to the development of a more circular economy by presenting a practical 10-step

  17. Electronic and vibrational spectroscopy and vibrationally mediated photodissociation of V+(OCO).

    Science.gov (United States)

    Citir, Murat; Altinay, Gokhan; Metz, Ricardo B

    2006-04-20

    Electronic spectra of gas-phase V+(OCO) are measured in the near-infrared from 6050 to 7420 cm(-1) and in the visible from 15,500 to 16,560 cm(-1), using photofragment spectroscopy. The near-IR band is complex, with a 107 cm(-1) progression in the metal-ligand stretch. The visible band shows clearly resolved vibrational progressions in the metal-ligand stretch and rock, and in the OCO bend, as observed by Brucat and co-workers. A vibrational hot band gives the metal-ligand stretch frequency in the ground electronic state nu3'' = 210 cm(-1). The OCO antisymmetric stretch frequency in the ground electronic state (nu1'') is measured by using vibrationally mediated photodissociation. An IR laser vibrationally excites ions to nu1'' = 1. Vibrationally excited ions selectively dissociate following absorption of a second, visible photon at the nu1' = 1 CO2, due to interaction with the metal. Larger blue shifts observed for complexes with fewer ligands agree with trends seen for larger V+(OCO)n clusters.

  18. Capacitance of circular patch resonator

    International Nuclear Information System (INIS)

    Miano, G.; Verolino, L.; Naples Univ.; Panariello, G.; Vaccaro, V.G.; Naples Univ.

    1995-11-01

    In this paper the capacitance of the circular microstrip patch resonator is computed. It is shown that the electrostatic problem can be formulated as a system of dual integral equations, and the most interesting techniques of solutions of these systems are reviewed. Some useful approximated formulas for the capacitance are derived and plots of the capacitance are finally given in a wide range of dielectric constants

  19. A new X-ray detector for magnetic circular dichroism experiments

    CERN Document Server

    Bateman, J E; Dudzik, E; Laan, G V D; Lipp, J D; Smith, A D; Stephenson, R

    2001-01-01

    X-ray magnetic circular dichroism (XMCD) studies of magnetic 3d transition metal samples require the recording of high quality absorption scans in high magnetic fields using circularly polarised soft X-rays of energies in the range 0.5-1 keV. A Gas Microstrip Detector is described which permits the option of using the X-ray fluorescence signal instead of the usual electron yield signal.

  20. Magnetic induction strength on surface of a ferro-medium circular cylinder

    Directory of Open Access Journals (Sweden)

    M. Jin

    2016-09-01

    Full Text Available Based on the Ampere molecular current hypothesis and the Biot–Savart law, a magnetic model on the metal magnetic memory (MMM testing of a specimen is proposed. Relation between magnetic flux leakage (MFL and magnetization of a ferro-medium circular cylinder is set up. We can predict magnetization of material according to the MFL on surface of the circular cylinder.

  1. Two-dimensional vibrational-electronic spectroscopy

    Science.gov (United States)

    Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira

    2015-10-01

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (νCN) and either a ligand-to-metal charge transfer transition ([FeIII(CN)6]3- dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN)5FeIICNRuIII(NH3)5]- dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific νCN modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a wide range of complex molecular, material, and biological systems.

  2. Two-dimensional vibrational-electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira, E-mail: mkhalil@uw.edu [Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195 (United States)

    2015-10-21

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (ν{sub CN}) and either a ligand-to-metal charge transfer transition ([Fe{sup III}(CN){sub 6}]{sup 3−} dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN){sub 5}Fe{sup II}CNRu{sup III}(NH{sub 3}){sub 5}]{sup −} dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific ν{sub CN} modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a

  3. Experimental study of the effect of icing on the aerodynamics of circular cylinders - Part II: Inclined flow

    DEFF Research Database (Denmark)

    Demartino, C.; Georgakis, Christos T.; Ricciardelli, F.

    are produced from HDPE, as used for bridge stays. Variations in the accretion parameters were chosen to generate the most common natural ice formations, which might also be expected to produce bridge cable vibrations. A parallel paper deals with the case of circular cylinders in cross flow....

  4. Vibration of hydraulic machinery

    CERN Document Server

    Wu, Yulin; Liu, Shuhong; Dou, Hua-Shu; Qian, Zhongdong

    2013-01-01

    Vibration of Hydraulic Machinery deals with the vibration problem which has significant influence on the safety and reliable operation of hydraulic machinery. It provides new achievements and the latest developments in these areas, even in the basic areas of this subject. The present book covers the fundamentals of mechanical vibration and rotordynamics as well as their main numerical models and analysis methods for the vibration prediction. The mechanical and hydraulic excitations to the vibration are analyzed, and the pressure fluctuations induced by the unsteady turbulent flow is predicted in order to obtain the unsteady loads. This book also discusses the loads, constraint conditions and the elastic and damping characters of the mechanical system, the structure dynamic analysis, the rotor dynamic analysis and the system instability of hydraulic machines, including the illustration of monitoring system for the instability and the vibration in hydraulic units. All the problems are necessary for vibration pr...

  5. Anti-vibration gloves?

    Science.gov (United States)

    Hewitt, Sue; Dong, Ren G; Welcome, Daniel E; McDowell, Thomas W

    2015-03-01

    For exposure to hand-transmitted vibration (HTV), personal protective equipment is sold in the form of anti-vibration (AV) gloves, but it remains unclear how much these gloves actually reduce vibration exposure or prevent the development of hand-arm vibration syndrome in the workplace. This commentary describes some of the issues that surround the classification of AV gloves, the assessment of their effectiveness and their applicability in the workplace. The available information shows that AV gloves are unreliable as devices for controlling HTV exposures. Other means of vibration control, such as using alternative production techniques, low-vibration machinery, routine preventative maintenance regimes, and controlling exposure durations are far more likely to deliver effective vibration reductions and should be implemented. Furthermore, AV gloves may introduce some adverse effects such as increasing grip force and reducing manual dexterity. Therefore, one should balance the benefits of AV gloves and their potential adverse effects if their use is considered. © Crown copyright 2014.

  6. Photoconductive detector of circularly polarized radiation based on a MIS structure with a CoPt layer

    Science.gov (United States)

    Kudrin, A. V.; Dorokhin, M. V.; Zdoroveishchev, A. V.; Demina, P. B.; Vikhrova, O. V.; Kalent'eva, I. L.; Ved', M. V.

    2017-11-01

    A photoconductive detector of circularly polarized radiation based on the metal-insulator-semiconductor structure of CoPt/(Al2O3/SiO2/Al2O3)/InGaAs/GaAs is created. The efficiency of detection of circularly polarized radiation is 0.75% at room temperature. The operation of the detector is based on the manifestation of the effect of magnetic circular dichroism in the CoPt layer, that is, the dependence of the CoPt transmission coefficient on the sign of the circular polarization of light and magnetization.

  7. Best Practice Examples of Circular Business Models

    DEFF Research Database (Denmark)

    Guldmann, Eva

    Best practice examples of circular business models are presented in this report. The purpose is to inform and inspire interested readers, in particular companies that aspire to examine the potentials of the circular economy. Circular business models in two different sectors are examined, namely...... the textile and clothing sector as well as the durable goods sector. In order to appreciate the notion of circular business models, the basics of the circular economy are outlined along with three frameworks for categorizing the various types of circular business models. The frameworks take point of departure...... in resource loops, value bases and business model archetypes respectively, and they are applied for analysing and organizing the business models that are presented throughout the report. The investigations in the report show that circular business models are relevant to businesses because they hold...

  8. The sorption of uranium(VI) and neptunium(V) onto surfaces of selected metal oxides and alumosilicates studied by in situ vibrational spectroscopy

    International Nuclear Information System (INIS)

    Mueller, Katharina

    2010-05-01

    The migration behavior of actinides and other radioactive contaminants in the environment is controlled by prominent molecular phenomena such as hydrolysis and complexation reactions in aqueous solutions as well as the diffusion and sorption onto minerals present along groundwater flow paths. These reactions significantly influence the mobility and bioavailability of the metal ions in the environment, in particular at liquid-solid interfaces. Hence, for the assessment of migration processes the knowledge of the mechanisms occurring at interfaces is crucial. The required structural information can be obtained using various spectroscopic techniques. In the present study, the speciation of uranium(VI) and neptunium(V) at environmentally relevant mineral-water interfaces of oxides of titania, alumina, silica, zinc, and alumosilicates has been investigated by the application of attenuated total reflection Fouriertransform infrared (ATR FT-IR) spectroscopy. Moreover, the distribution of the hydrolysis products in micromolar aqueous solutions of U(VI) and Np(V/VI) at ambient atmosphere has been characterized for the first time, by a combination of ATR FT-IR spectroscopy, near infrared (NIR) absorption spectroscopy, and speciation modeling applying updated thermodynamic databases. From the infrared spectra, a significant change of the U(VI) speciation is derived upon lowering the U(VI) concentration from the milli- to the micromolar range, strongly suggesting the dominance of monomeric U(VI) hydrolysis products in the micromolar solutions. In contradiction to the predicted speciation, monomeric hydroxo species are already present at pH ≥ 2.5 and become dominant at pH 3. At higher pH levels (> 6), a complex speciation is evidenced including carbonate containing complexes. For the first time, spectroscopic results of Np(VI) hydrolysis reactions are provided in the submillimolar concentration range and at pH values up to 5.3, and they are comparatively discussed with U

  9. Electronic energy transfer through non-adiabatic vibrational-electronic resonance. II. 1D spectra for a dimer

    Science.gov (United States)

    Tiwari, Vivek; Jonas, David M.

    2018-02-01

    Vibrational-electronic resonance in photosynthetic pigment-protein complexes invalidates Förster's adiabatic framework for interpreting spectra and energy transfer, thus complicating determination of how the surrounding protein affects pigment properties. This paper considers the combined effects of vibrational-electronic resonance and inhomogeneous variations in the electronic excitation energies of pigments at different sites on absorption, emission, circular dichroism, and hole-burning spectra for a non-degenerate homodimer. The non-degenerate homodimer has identical pigments in different sites that generate differences in electronic energies, with parameters loosely based on bacteriochlorophyll a pigments in the Fenna-Matthews-Olson antenna protein. To explain the intensity borrowing, the excited state vibrational-electronic eigenvectors are discussed in terms of the vibrational basis localized on the individual pigments, as well as the correlated/anti-correlated vibrational basis delocalized over both pigments. Compared to those in the isolated pigment, vibrational satellites for the correlated vibration have the same frequency and precisely a factor of 2 intensity reduction through vibrational delocalization in both absorption and emission. Vibrational satellites for anti-correlated vibrations have their relaxed emission intensity reduced by over a factor 2 through vibrational and excitonic delocalization. In absorption, anti-correlated vibrational satellites borrow excitonic intensity but can be broadened away by the combination of vibronic resonance and site inhomogeneity; in parallel, their vibronically resonant excitonic partners are also broadened away. These considerations are consistent with photosynthetic antenna hole-burning spectra, where sharp vibrational and excitonic satellites are absent. Vibrational-excitonic resonance barely alters the inhomogeneously broadened linear absorption, emission, and circular dichroism spectra from those for a

  10. Vibrational spectroscopy in the electron microscope.

    Science.gov (United States)

    Krivanek, Ondrej L; Lovejoy, Tracy C; Dellby, Niklas; Aoki, Toshihiro; Carpenter, R W; Rez, Peter; Soignard, Emmanuel; Zhu, Jiangtao; Batson, Philip E; Lagos, Maureen J; Egerton, Ray F; Crozier, Peter A

    2014-10-09

    Vibrational spectroscopies using infrared radiation, Raman scattering, neutrons, low-energy electrons and inelastic electron tunnelling are powerful techniques that can analyse bonding arrangements, identify chemical compounds and probe many other important properties of materials. The spatial resolution of these spectroscopies is typically one micrometre or more, although it can reach a few tens of nanometres or even a few ångströms when enhanced by the presence of a sharp metallic tip. If vibrational spectroscopy could be combined with the spatial resolution and flexibility of the transmission electron microscope, it would open up the study of vibrational modes in many different types of nanostructures. Unfortunately, the energy resolution of electron energy loss spectroscopy performed in the electron microscope has until now been too poor to allow such a combination. Recent developments that have improved the attainable energy resolution of electron energy loss spectroscopy in a scanning transmission electron microscope to around ten millielectronvolts now allow vibrational spectroscopy to be carried out in the electron microscope. Here we describe the innovations responsible for the progress, and present examples of applications in inorganic and organic materials, including the detection of hydrogen. We also demonstrate that the vibrational signal has both high- and low-spatial-resolution components, that the first component can be used to map vibrational features at nanometre-level resolution, and that the second component can be used for analysis carried out with the beam positioned just outside the sample--that is, for 'aloof' spectroscopy that largely avoids radiation damage.

  11. Searching for Models Exhibiting High Circularly Polarized Luminescence: the Electroactive Inherently Chiral Oligothiophenes.

    Science.gov (United States)

    Benincori, Tiziana; Appoloni, Giulio; Mussini, Patrizia Romana; Arnaboldi, Serena; Cirilli, Roberto; Quartapelle Procopio, Elsa; Panigati, Monica; Abbate, Sergio; Mazzeo, Giuseppe; Longhi, Giovanna

    2018-05-02

    Two new inherently chiral oligothiophenes characterized by the atropisomeric 3,3'-bithianaphtene scaffold functionalized with fused ring bithiophene derivatives, namely 4H-cyclopenta [2,1-b3:4b']dithiophene (CPDT) and dithieno[3,3-b:2',3'-d]pyrrole (DTP), were synthesized. The racemates were fully characterized and resolved into antipodes by enantioselective HPLC. The enantiomers were analyzed through different chiroptical techniques: electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) were employed to attribute the absolute configuration (AC). Comparison of experimental and calculated VCD spectra confirmed the DFT calculated conformational characteristics. The compound functionalized with two CPDT units was oxidized with FeCl3 and ECD and CPL of the resulting material were measured. Circularly Polarized Luminescence (CPL) was measured in order to verify if inherently chiral oligothiophenes could be promising systems for chiral photonics applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Chiral retrieval method based on right circularly polarized and left circularly polarized waves

    International Nuclear Information System (INIS)

    Martín, Ernesto; Muñoz, Juan; Margineda, José; Molina-Cuberos, Gregorio J; García-Collado, Ángel J

    2014-01-01

    The free-wave characterization of metamaterials is usually carried out by illuminating a sample with a linearly polarized plane electromagnetic wave. At points before and after the sample, sensors are introduced to measure the transverse components of the field, in order to compute the reflection and transmission coefficients related with the co- and cross-polar field components. Based on this information, retrieval algorithms allow parameters like rotation angle, effective chirality and refraction index to be calculated. Here we propose to use the transmission signals under illumination with plane circularly polarized waves, without sensing the reflection signal, to calculate the chirality parameter and the rotation angle due to the electromagnetic activity of the material. This new method, which allows a simpler characterization of a chiral slab, is applied to the study of metamaterials composed of both periodic and random distributions of metallic structures with chiral symmetry. The experimental results are contrasted with simulations and alternative measurements obtained using linearly polarized waves. (paper)

  13. Bandshapes in vibrational spectroscopy

    International Nuclear Information System (INIS)

    Dijkman, F.G.

    1978-01-01

    A detailed account is given of the development of modern bandshape theories since 1965. An investigation into the relative contributions of statistical irreversible relaxation processes is described, for a series of molecules in which gradually the length of one molecular axis is increased. An investigation into the theoretical and experimental investigation of the broadening brought about by the effect of fluctuating intermolecular potentials on the vibrational frequency is also described. The effect of an intermolecular perturbative potential on anharmonic and Morse oscillators is discussed and the results are presented of a computation on the broadening of the vibrational band of some diatomic molecules in a rigid lattice type solvent. The broadening of the OH-stretching vibration in a number of aliphatic alcohols, the vibrational bandshapes of the acetylenic C-H stretching vibration and of the symmetric methyl stretching vibration are investigated. (Auth./ C.F.)

  14. A Novel Dual-Band Circularly Polarized Rectangular Slot Antenna

    Directory of Open Access Journals (Sweden)

    Biao Li

    2016-01-01

    Full Text Available A coplanar waveguide fed dual-band circularly polarized rectangular slot antenna is presented. The proposed antenna consists of a rectangular metal frame acting as a ground and an S-shaped monopole as a radiator. The spatial distribution of the surface current density is employed to demonstrate that the circular polarization is generated by the S-shaped monopole which controls the path of the surface currents. An antenna prototype, having overall dimension 37 × 37 × 1 mm3, has been fabricated on FR4 substrate with dielectric constant 4.4. The proposed antenna achieves 10 dB return loss bandwidths and 3 dB axial ratio (AR in the frequency bands 2.39–2.81 GHz and 5.42–5.92 GHz, respectively. Both these characteristics are suitable for WLAN and WiMAX applications.

  15. Transfer vibration through spine

    OpenAIRE

    Benyovszky, Adam

    2012-01-01

    Transfer Vibration through Spine Abstract In the bachelor project we deal with the topic of Transfer Vibration through Spine. The problem of TVS is trying to be solved by the critical review method. We analyse some diagnostic methods and methods of treatment based on this principle. Close attention is paid to the method of Transfer Vibration through Spine that is being currently solved by The Research Institute of Thermomechanics in The Czech Academy of Sciences in cooperation with Faculty of...

  16. Omnidirectional narrow optical filters for circularly polarized light in a nanocomposite structurally chiral medium.

    Science.gov (United States)

    Avendaño, Carlos G; Palomares, Laura O

    2018-04-20

    We consider the propagation of electromagnetic waves throughout a nanocomposite structurally chiral medium consisting of metallic nanoballs randomly dispersed in a structurally chiral material whose dielectric properties can be represented by a resonant effective uniaxial tensor. It is found that an omnidirectional narrow pass band and two omnidirectional narrow band gaps are created in the blue optical spectrum for right and left circularly polarized light, as well as narrow reflection bands for right circularly polarized light that can be controlled by varying the light incidence angle and the filling fraction of metallic inclusions.

  17. Attenuation in Superconducting Circular Waveguides

    Directory of Open Access Journals (Sweden)

    K. H. Yeap

    2016-09-01

    Full Text Available We present an analysis on wave propagation in superconducting circular waveguides. In order to account for the presence of quasiparticles in the intragap states of a superconductor, we employ the characteristic equation derived from the extended Mattis-Bardeen theory to compute the values of the complex conductivity. To calculate the attenuation in a circular waveguide, the tangential fields at the boundary of the wall are first matched with the electrical properties (which includes the complex conductivity of the wall material. The matching of fields with the electrical properties results in a set of transcendental equations which is able to accurately describe the propagation constant of the fields. Our results show that although the attenuation in the superconducting waveguide above cutoff (but below the gap frequency is finite, it is considerably lower than that in a normal waveguide. Above the gap frequency, however, the attenuation in the superconducting waveguide increases sharply. The attenuation eventually surpasses that in a normal waveguide. As frequency increases above the gap frequency, Cooper pairs break into quasiparticles. Hence, we attribute the sharp rise in attenuation to the increase in random collision of the quasiparticles with the lattice structure.

  18. Chemical Synthesis of Circular Proteins*

    Science.gov (United States)

    Tam, James P.; Wong, Clarence T. T.

    2012-01-01

    Circular proteins, once thought to be rare, are now commonly found in plants. Their chemical synthesis, once thought to be difficult, is now readily achievable. The enabling methodology is largely due to the advances in entropic chemical ligation to overcome the entropy barrier in coupling the N- and C-terminal ends of large peptide segments for either intermolecular ligation or intramolecular ligation in end-to-end cyclization. Key elements of an entropic chemical ligation consist of a chemoselective capture step merging the N and C termini as a covalently linked O/S-ester intermediate to permit the subsequent step of an intramolecular O/S-N acyl shift to form an amide. Many ligation methods exploit the supernucleophilicity of a thiol side chain at the N terminus for the capture reaction, which makes cysteine-rich peptides ideal candidates for the entropy-driven macrocyclization. Advances in desulfurization and modification of the thiol-containing amino acids at the ligation sites to other amino acids add extra dimensions to the entropy-driven ligation methods. This minireview describes recent advances of entropy-driven ligation to prepare circular proteins with or without a cysteinyl side chain. PMID:22700959

  19. A High-Order Theory for the Analysis of Circular Cylindrical Composite Sandwich Shells with Transversely Compliant Core Subjected to External Loads

    DEFF Research Database (Denmark)

    Rahmani, Omid; Khalili, S.M.R.; Thomsen, Ole Thybo

    2012-01-01

    A new model based on the high order sandwich panel theory is proposed to study the effect of external loads on the free vibration of circular cylindrical composite sandwich shells with transversely compliant core, including also the calculation of the buckling loads. In the present model......, which is based on a 3D elasticity solution for the core material, can be used as a benchmark in future studies of the free vibration and buckling of circular cylindrical composite sandwich shells with a transversely compliant core....

  20. Mechanical vibration and shock analysis, sinusoidal vibration

    CERN Document Server

    Lalanne, Christian

    2014-01-01

    Everything engineers need to know about mechanical vibration and shock...in one authoritative reference work! This fully updated and revised 3rd edition addresses the entire field of mechanical vibration and shock as one of the most important types of load and stress applied to structures, machines and components in the real world. Examples include everything from the regular and predictable loads applied to turbines, motors or helicopters by the spinning of their constituent parts to the ability of buildings to withstand damage from wind loads or explosions, and the need for cars to m

  1. Hydroelastic Vibrations of Ships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Folsø, Rasmus

    2002-01-01

    A formula for the necessary hull girder bending stiffness required to avoid serious springing vibrations is derived. The expression takes into account the zero crossing period of the waves, the ship speed and main dimensions. For whipping vibrations the probability of exceedance for the combined...

  2. Surface vibrational spectroscopy

    International Nuclear Information System (INIS)

    Erskine, J.L.

    1984-01-01

    A brief review of recent studies which combine measurements of surface vibrational energies with lattice dynamical calculations is presented. These results suggest that surface vibrational spectroscopy offers interesting prospects for use as a molecular-level probe of surface geometry, adsorbate bond distances and molecular orientations

  3. Gearbox vibration diagnostic analyzer

    Science.gov (United States)

    1992-01-01

    This report describes the Gearbox Vibration Diagnostic Analyzer installed in the NASA Lewis Research Center's 500 HP Helicopter Transmission Test Stand to monitor gearbox testing. The vibration of the gearbox is analyzed using diagnostic algorithms to calculate a parameter indicating damaged components.

  4. Handbook Of Noise And Vibration

    International Nuclear Information System (INIS)

    1995-12-01

    This book is about noise and vibration. The first chapter has explanations of noise such as basic of sound, influence of noise, assessment of noise, measurement of prevention of noise and technology, case of noise measurement and soundproof. The second chapter describes vibration with outline, theory of vibration, interpretation of vibration, measurement for reduction of vibration, case of design of protection against vibration. It deals with related regulation and method of measurement.

  5. Piezoelectric ceramic-reinforced metal matrix composites

    OpenAIRE

    2004-01-01

    Composite materials comprising piezoelectric ceramic particulates dispersed in a metal matrix are capable of vibration damping. When the piezoelectric ceramic particulates are subjected to strain, such as the strain experienced during vibration of the material, they generate an electrical voltage that is converted into Joule heat in the surrounding metal matrix, thereby dissipating the vibrational energy. The piezoelectric ceramic particulates may also act as reinforcements to improve the mec...

  6. Vibration insensitive interferometry

    Science.gov (United States)

    Millerd, James; Brock, Neal; Hayes, John; Kimbrough, Brad; North-Morris, Michael; Wyant, James C.

    2017-11-01

    The largest limitation of phase-shifting interferometry for optical testing is the sensitivity to the environment, both vibration and air turbulence. An interferometer using temporal phase-shifting is very sensitive to vibration because the various phase shifted frames of interferometric data are taken at different times and vibration causes the phase shifts between the data frames to be different from what is desired. Vibration effects can be reduced by taking all the phase shifted frames simultaneously and turbulence effects can be reduced by averaging many measurements. There are several techniques for simultaneously obtaining several phase-shifted interferograms and this paper will discuss two such techniques: 1) Simultaneous phase-shifting interferometry on a single detector array (PhaseCam) and 2) Micropolarizer phase-shifting array. The application of these techniques for the testing of large optical components, measurement of vibrational modes, the phasing of segmented optical components, and the measurement of deformations of large diffuse structures is described.

  7. Vibrations of rotating machinery

    CERN Document Server

    Matsushita, Osami; Kanki, Hiroshi; Kobayashi, Masao; Keogh, Patrick

    2017-01-01

    This book opens with an explanation of the vibrations of a single degree-of-freedom (dof) system for all beginners. Subsequently, vibration analysis of multi-dof systems is explained by modal analysis. Mode synthesis modeling is then introduced for system reduction, which aids understanding in a simplified manner of how complicated rotors behave. Rotor balancing techniques are offered for rigid and flexible rotors through several examples. Consideration of gyroscopic influences on the rotordynamics is then provided and vibration evaluation of a rotor-bearing system is emphasized in terms of forward and backward whirl rotor motions through eigenvalue (natural frequency and damping ratio) analysis. In addition to these rotordynamics concerning rotating shaft vibration measured in a stationary reference frame, blade vibrations are analyzed with Coriolis forces expressed in a rotating reference frame. Other phenomena that may be assessed in stationary and rotating reference frames include stability characteristic...

  8. Circular economy and nuclear energy

    International Nuclear Information System (INIS)

    2016-01-01

    Circular economy means no production of waste through re-using and recycling. As other industries, nuclear industry has committed itself to a policy of sustainability and resource preservation. EDF has developed a 5 point strategy: 1) the closure of the fuel cycle through recycling, 2) operating nuclear power plants beyond 40 years, 3) reducing the volume of waste, 4) diminishing the consumption of energy through the implementation of new processes (for instance the enrichment through centrifugation uses 50 times less power than gaseous diffusion enrichment) and 5) making evolve the prevailing doctrine concerning the management of very low level radioactive waste: making possible the re-use of slightly contaminated steel scrap or concrete instead of storing them in dedicated disposal centers. (A.C.)

  9. Circular economy and nuclear energy

    International Nuclear Information System (INIS)

    2017-01-01

    This article first recalls what circular economy is, and its main principles (sustainable supply, eco-design, industrial and territorial ecology, economy of function rather than of possession, extension of product lifetime, recycling). It outlines its different benefits: improved resilience, inclusion of all actors of the territory, creation of local jobs, a global vision. In the next part, the nuclear industry is presented as a pioneer in this respect through various trends and developments: closure of the fuel cycle and saving of uranium and energy in the upstream part, reduction of wastes in the downstream part, exploitation of plants on a longer term, management of the production of conventional wastes, reduction of energy consumption, evolution of the doctrine in terms of management of very low level radioactive wastes

  10. Some properties of circular proteins

    International Nuclear Information System (INIS)

    Prosselkov, P.; John, P.; Dixon, N.E.; Liepinsh, E.; Williams, N.K.; University of Sydney, NSW; Matthews, J.M.; Otting, G.; Karolinska Institutet, Stockholm,

    2002-01-01

    Full text: Protein backbone cyclization can be achieved by use of a circularly-permuted split mini-intein. We have used the small N-terminal domain of the E coli DnaB helicase (DnaB-N, residues 24-136) as a model protein for cyclization because its structure has been determined both by NMR spectroscopy and X-ray crystallography, and its ends are close together. Joining of the ends of DnaB-N' via a 9-amino acid linker occurs efficiently in vivo, and the circular (cz-) protein is stabilized in comparison to the linear (Hn-) protein against thermal denaturation (ΔΔG ∼2 kcal/mol). DnaB-N exists as a dimer in the crystalline state and in solution at high concentrations. To produce linear and cyclized versions that could not dimerize, Phe102 (at the dimer interface) was changed to Glu. NMR spectra showed that the F102E mutants remained monomeric at high concentrations but otherwise had essentially the same structures as the wild-type domains. Individual rate constants for proton exchange at the amide groups in lin- and cz-DnaB-N were determined at 10 C. Although they varied as expected depending on exposure to solvent, the ratios of rates between corresponding amides in the two proteins were constant. In the same buffer, lin- and cz-DnaB-N both unfolded reversibly, with transition temperatures of 37.9 and 48.5 deg C, respectively. Correlation of the (constant) ratio of amide exchange rates with measured thermodynamic parameters suggests that amide exchange in DnaB-N occurs predominantly in a globally unfolded state. Similar studies with other proteins are underway

  11. Multiband Circular Polarizer Based on Fission Transmission of Linearly Polarized Wave for X-Band Applications

    Directory of Open Access Journals (Sweden)

    Farman Ali Mangi

    2016-01-01

    Full Text Available A multiband circular polarizer based on fission transmission of linearly polarized wave for x-band application is proposed, which is constructed of 2 × 2 metallic strips array. The linear-to-circular polarization conversion is obtained by decomposing the linearly incident x-polarized wave into two orthogonal vector components of equal amplitude and 90° phase difference between them. The innovative approach of “fission transmission of linear-to-circular polarized wave” is firstly introduced to obtain giant circular dichroism based on decomposition of orthogonal vector components through the structure. It means that the incident linearly polarized wave is converted into two orthogonal components through lower printed metallic strips layer and two transmitted waves impinge on the upper printed strips layer to convert into four orthogonal vector components at the end of structure. This projection and transmission sequence of orthogonal components sustain the chain transmission of electromagnetic wave and can achieve giant circular dichroism. Theoretical analysis and microwave experiments are presented to validate the performance of the structure. The measured results are in good agreement with simulation results. In addition, the proposed circular polarizer exhibits the optimal performance with respect to the normal incidence. The right handed circularly polarized wave is emitted ranging from 10.08 GHz to 10.53 GHz and 10.78 GHz to 11.12 GHz, while the left handed circular polarized wave is excited at 10.54 GHz–10.70 GHz and 11.13 GHz–11.14 GHz, respectively.

  12. A numerical simulation of VIV on a flexible circular cylinder

    International Nuclear Information System (INIS)

    Xie Fangfang; Deng Jian; Zheng Yao; Xiao Qing

    2012-01-01

    In this paper, numerical simulations of a flexible circular cylinder subjected to a vortex-induced vibration (VIV) are conducted. The Reynolds number for simulations is fixed at 1000. The finite volume method is applied for modeling fluid flow with the moving meshes feature. The dynamic response of a flexible cylinder fixed at both ends is modeled by the Euler–Bernoulli beam theory. The comparison between two-dimensional (2D) simulations and 3D simulations for the flexible cylinder shows that the maximum response amplitude of the cross-flow oscillation is about 0.57D for 2D rigid cylinders (modeled by a spring–damper–mass model) and 1.03D for flexible cylinders, respectively. The results from 3D simulations are closer to previous experimental results. Furthermore, the results obtained with various frequency ratios show that different wake patterns exist according to the frequency ratio, such as 2S mode, 2P mode and some more complicated modes. The wake pattern is different at various sections along the cylinder length, due to the fact that the two ends of the beam are fixed. The vibration of the flexible cylinder can also greatly alter the three dimensionality in the wake, which is our research in future work, especially in the transition region for Reynolds number ranging from 170 to 300. (paper)

  13. Acoustic and Vibration Control for an Underwater Structure under Mechanical Excitation

    Directory of Open Access Journals (Sweden)

    Shi-Jian Zhu

    2014-01-01

    Full Text Available Acoustic and vibration control for an underwater structure under mechanical excitation has been investigated by using negative feedback control algorithm. The underwater structure is modeled with cylindrical shells, conical shells, and circular bulkheads, of which the motion equations are built with the variational approach, respectively. Acoustic property is analyzed by the Helmholtz integration formulation with boundary element method. Based on negative feedback control algorithm, a control loop with a coupling use of piezoelectric sensor and actuator is built, and accordingly some numerical examples are carried out on active control of structural vibration and acoustic response. Effects of geometrical and material parameters on acoustic and vibration properties are investigated and discussed.

  14. Circular relativistic motion of two identical bodies

    International Nuclear Information System (INIS)

    Shavokhina, N.S.

    1983-01-01

    Circular relativistic motion of two bodies as a solution of the earlier obtained equations with a deflecting argument where the self-deflection of the argument is an unknown function of time is considered. In case of circular motion the argument deflection is independent from time and it is the root of the transcendental equation obtained in the paper

  15. The circular economy applied to local communities

    NARCIS (Netherlands)

    van der Blonk, Heico; van Spijk, Alex; van der Schoor, Tineke

    2015-01-01

    Based on a theoretical discussion the main difference between models of lineair economy and circular economy are elaborated; (1) Elimination of waste is essential the circulation of circular flows and reclamation of (raw) materials; this requires mechanisms for the return of obsolete materials. (2)

  16. Culture as a Caveat Towards Circular Economy

    DEFF Research Database (Denmark)

    Guerrieri, Valeria

    2015-01-01

    Circular economy represents an economic and political challenge, as well as a cultural one, requiring a massive transformation on all levels of society. But why is cultural change so important to understanding today’s economy and how can the circular model be considered a truly cross-cultural...

  17. Dual-Resonant Implantable Circular Patch Antenna for Biotelemetry Communication

    Directory of Open Access Journals (Sweden)

    Rongqiang Li

    2016-01-01

    Full Text Available A compact broadband implantable circular patch antenna is designed and experimentally demonstrated for Medical Implant Communications Service (MICS band (402–405 MHz. Compared with other similar implantable antennas, the proposed antenna incorporates three advantages for biotelemetry communication. First, it can realize a broad impedance bandwidth by exhibiting dual resonances. Second, it can obtain a compact structure by introducing two arc-shaped slots, a rectangular slot and a circular slot on metal radiating patch. Finally, it can display a friendly shape by using a circular structure. The proposed antenna occupies a volume of about 431.5 mm3 (10.42 × 1.27π mm3, which is a compromise between miniaturization and bandwidth. The measured −10 dB impedance bandwidth is 55 MHz (385–440 MHz. Furthermore, the radiation performance and human body safety consideration of the antenna are examined and characterized.

  18. Perceptions of Circular Business Models in SMEs

    Directory of Open Access Journals (Sweden)

    Sebastian-Ion Ceptureanu

    2018-05-01

    Full Text Available Testing circular economy business models is crucial in understanding Circular Economy features across various industries. This paper analyses Circular Economy perceptions in Romanian SMEs by investigating entrepreneurs from PVC joinery industry. Using a multidimensional framework, ReSOLVE, as a conceptual model, and Lewandowski systematization, we measured 6 business actions and their relations with Value creation. The results of our survey can be described as mixed. Of the 6 business actions of ReSOLVE framework, for half of them (Regenerate, Optimize and Exchange we can definitely conclude that these are correlated with Circular Economy in terms of Value Creation, while for a fourth there are variables significantly correlated without being able to conclude its overall contribution in terms of Value creation. Our empirical investigation contributes to literature development on Circular Economy research in SMEs and a step forward to shape future research initiatives.

  19. Fatigue damage from random vibration pulse process of tubular structural elements subject to wind

    DEFF Research Database (Denmark)

    Christensen, Claus F.; Ditlevsen, Ove Dalager

    1997-01-01

    In a wide range of the Reynolds number an elastically suspended circular cylinder surrounded by a homogeneous wind velocity field will generate vortex shedding of a frequency that by and large is proportional to the far field wind velocity. However, if the cylinder is free to vibrate, resonance w...

  20. Nonplanar Tertiary Amides in Rigid Chiral Tricyclic Dilactams. Peptide Group Distortions and Vibrational Optical Activity

    Czech Academy of Sciences Publication Activity Database

    Pazderková, Markéta; Profant, V.; Hodačová, J.; Šebestík, Jaroslav; Pazderka, T.; Novotná, P.; Urbanová, M.; Šafařík, Martin; Buděšínský, Miloš; Tichý, Miloš; Bednárová, Lucie; Baumruk, V.; Maloň, Petr

    2013-01-01

    Roč. 117, č. 33 (2013), s. 9626-9642 ISSN 1520-6106 R&D Projects: GA ČR GAP205/10/1276 Institutional support: RVO:61388963 Keywords : spirodilactams * amide bond * vibrational circular dichroism * non-planarity * Raman optical activity Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.377, year: 2013

  1. Silicon micromachined vibrating gyroscopes

    Science.gov (United States)

    Voss, Ralf

    1997-09-01

    This work gives an overview of silicon micromachined vibrating gyroscopes. Market perspectives and fields of application are pointed out. The advantage of using silicon micromachining is discussed and estimations of the desired performance, especially for automobiles are given. The general principle of vibrating gyroscopes is explained. Vibrating silicon gyroscopes can be divided into seven classes. for each class the characteristic principle is presented and examples are given. Finally a specific sensor, based on a tuning fork for automotive applications with a sensitivity of 250(mu) V/degrees is described in detail.

  2. System Detects Vibrational Instabilities

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1990-01-01

    Sustained vibrations at two critical frequencies trigger diagnostic response or shutdown. Vibration-analyzing electronic system detects instabilities of combustion in rocket engine. Controls pulse-mode firing of engine and identifies vibrations above threshold amplitude at 5.9 and/or 12kHz. Adapted to other detection and/or control schemes involving simultaneous real-time detection of signals above or below preset amplitudes at two or more specified frequencies. Potential applications include rotating machinery and encoders and decoders in security systems.

  3. Coherent vibrational dynamics

    CERN Document Server

    Lanzani, Guglielmo; De Silvestri, Sandro

    2007-01-01

    Vibrational spectroscopy is a powerful investigation tool for a wide class of materials covering diverse areas in physics, chemistry and biology. The continuous development in the laser field regarding ultrashort pulse generation has led to the possibility of producing light pulses that can follow vibrational motion coupled to the electronic transitions in molecules and solids in real time. Aimed at researchers and graduate students using vibrational spectroscopy, this book provides both introductory chapters as well as more advanced contents reporting on recent progress. It also provides a good starting point for scientists seeking a sound introduction to ultrafast optics and spectroscopic techniques.

  4. Heat transfer in the thermal entrance region of a circular tube with axial heat conduction

    International Nuclear Information System (INIS)

    Zhang Changquan.

    1985-01-01

    This paper recounts the effects of axial heat conduction and convective boundary conditions on the heat transfer in the thermal entrance region of a circular tube under uniform flow, and the corresponding calculation is made. It will be profitable for the heat transfer studies on the pipe entrance region of low Prandtl number (liquid metal), or flow of low Peclet number. (author)

  5. Stress distribution in a semi-infinite body symmetrically loaded over a circular area

    Science.gov (United States)

    Mcginness, H.

    1980-01-01

    Algorithms are developed for computing stresses in a semi-infinite body when loaded by a uniform pressure acting over a circular area. The algorithm allows easy determination of any stress component in a semi-infinite body having a known Poisson's ratio. Example curves are plotted for Portland cement grout and metal representative values.

  6. Equilibrium structure and atomic vibrations of Nin clusters

    Science.gov (United States)

    Borisova, Svetlana D.; Rusina, Galina G.

    2017-12-01

    The equilibrium bond lengths and binding energy, second differences in energy and vibrational frequencies of free clusters Nin (2 ≤ n ≤ 20) were calculated with the use of the interaction potential obtained in the tight-binding approximation (TBA). The results show that the minimum vibration frequency plays a significant role in the evaluation of the dynamic stability of the clusters. A nonmonotonic dependence of the minimum vibration frequency of clusters on their size and the extreme values for the number of atoms in a cluster n = 4, 6, 13, and 19 are demonstrated. This result agrees with the theoretical and experimental data on stable structures of small metallic clusters.

  7. PREFACE: Vibrations at surfaces Vibrations at surfaces

    Science.gov (United States)

    Rahman, Talat S.

    2011-12-01

    This special issue is dedicated to the phenomenon of vibrations at surfaces—a topic that was indispensible a couple of decades ago, since it was one of the few phenomena capable of revealing the nature of binding at solid surfaces. For clean surfaces, the frequencies of modes with characteristic displacement patterns revealed how surface geometry, as well as the nature of binding between atoms in the surface layers, could be different from that in the bulk solid. Dispersion of the surface phonons provided further measures of interatomic interactions. For chemisorbed molecules on surfaces, frequencies and dispersion of the vibrational modes were also critical for determining adsorption sites. In other words, vibrations at surfaces served as a reliable means of extracting information about surface structure, chemisorption and overlayer formation. Experimental techniques, such as electron energy loss spectroscopy and helium-atom-surface scattering, coupled with infra-red spectroscopy, were continually refined and their resolutions enhanced to capture subtleties in the dynamics of atoms and molecules at surfaces. Theoretical methods, whether based on empirical and semi-empirical interatomic potential or on ab initio electronic structure calculations, helped decipher experimental observations and provide deeper insights into the nature of the bond between atoms and molecules in regions of reduced symmetry, as encountered on solid surfaces. Vibrations at surfaces were thus an integral part of the set of phenomena that characterized surface science. Dedicated workshops and conferences were held to explore the variety of interesting and puzzling features revealed in experimental and theoretical investigations of surface vibrational modes and their dispersion. One such conference, Vibrations at Surfaces, first organized by Harald Ibach in Juelich in 1980, continues to this day. The 13th International Conference on Vibrations at Surfaces was held at the University of

  8. Axis vibration detection device for reactor recycling pump

    International Nuclear Information System (INIS)

    Ide, Katsuki.

    1995-01-01

    The present invention provides a device for detecting, in a contactless manner, vibrations of a recycling pump shaft disposed in a reactor pressure vessel of a BWR type reactor. Namely, the vibration detector comprises an eddy current type displacement gauge having a sensing portion at one end of a linear tube type metal holder. It also comprises a rotational member made of an electroconductive material rotating integrally with a rotational pump shaft. The vibration detector is inserted into an attaching hole passing through a pump casing at a position where the sensing portion faces the outer circumference of the rotational member. The attaching hole is closed by a holder of the oscillation detector and a metal cap integrated to one end of the holder. A high pressure hermetic seal connector is disposed at a position outer side of the attaching hole of the vibration detector for electrically connecting the inside and the outside thereof. The device of the present invention can directly detect the vibration of the pump shaft. As a result, an abnormality, if should occur, in the recycling pump can be found in an early stage. Since the vibration detector is covered with a metal and shielded by the high pressure hermetic seal connector, it can sufficiently ensure pressure resistance. (I.S.)

  9. Vibration Theory, Vol. 3

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

    The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 4th edition of this textbook on linear stochastic vibration th...... theory is unchanged in comparison to the 3rd edition. Only a few errors have been corrected.......The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 4th edition of this textbook on linear stochastic vibration...

  10. Improved Laser Vibration Radar

    National Research Council Canada - National Science Library

    Hilaire, Pierre

    1998-01-01

    .... This thesis reconfigured an existing CO2 laboratory laser radar system that is capable of measuring the frequencies of vibration of a simulated target into a more compact and rugged form for field testing...

  11. NIF Ambient Vibration Measurements

    International Nuclear Information System (INIS)

    Noble, C.R.; Hoehler, M.S.; S.C. Sommer

    1999-01-01

    LLNL has an ongoing research and development project that includes developing data acquisition systems with remote wireless communication for monitoring the vibrations of large civil engineering structures. In order to establish the capability of performing remote sensing over an extended period of time, the researchers needed to apply this technology to a real structure. The construction of the National Ignition Facility provided an opportunity to test the data acquisition system on a large structure to monitor whether the facility is remaining within the strict ambient vibration guidelines. This document will briefly discuss the NIF ambient vibration requirements and summarize the vibration measurements performed during the Spring and Summer of 1999. In addition, a brief description of the sensors and the data acquisition systems will be provided in Appendix B

  12. A vibration sieve

    Energy Technology Data Exchange (ETDEWEB)

    Alekhin, S.A.; Denisenko, V.V.; Dzhalalov, M.G.; Kirichek, F.P.; Pitatel, Yu.A.; Prokopov, L.I.; Tikhonov, Yu.P.

    1982-01-01

    A vibration sieve is proposed which includes a vibration drive, a body and a screen installed on shock absorbers, a device for washing out the screen, and a subassembly for loading the material. To increase the operational reliability and effectiveness of the vibration sieve by improving the cleaning of the screen, the loading subassembly is equipped with a baffle with a lever which is hinged to it. The device for washing out the screen is made in the form of an electromagnet with a connecting rod, a switch and an eccentric, a friction ratchet mechanism and sprinkling systems. Here, the latter are interconnected, using a connecting rod, while the sprinkling system is installed on rollers under the screen. The electromagnetic switch is installed under the lever. The body is made with grooves for installing the sprinkling system. The vibration sieve is equipped with a switch which interacts with the connecting rod. The friction ratchet mechanism is equipped with a lug.

  13. FUTURE CIRCULAR COLLIDER LOGISTICS STUDY

    CERN Document Server

    Beißert, Ulrike; Kuhlmann, Gerd; Nettsträter, Andreas; Prasse, Christian; Wohlfahrt, Andreas

    2018-01-01

    The Large Hadron Collider (LHC) at the European Organization for Nuclear Research CERN in Geneva is the largest and most powerful collider in the world. CERN and its research and experimental infrastructure is not only a focus for the science community but is also very much in the public eye. With the Future Circular Collider (FCC) Study, CERN has begun to examine the feasibility of a new underground accelerator ring with a length of approximately 100 kilometres. Logistics is of great importance for the construction, assembly and operation of the FCC. During the planning, construction and assembly of the LHC, logistics proved to be one of the key factors. As the FCC is even larger than the LHC, logistics will also become more and more significant. This report therefore shows new concepts, methods and analytics for logistics, supply chain and transport concepts as part of the FCC study. This report deals with three different logistics aspects for the planning and construction phase of FCC: 1. A discussion of d...

  14. Structural Stability and Vibration

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Pedersen, Pauli

    This book offers an integrated introduction to the topic of stability and vibration. Strikingly, it describes stability as a function of boundary conditions and eigenfrequency as a function of both boundary conditions and column force. Based on a post graduate course held by the author at the Uni...... and their derivation, thus stimulating them to write interactive and dynamic programs to analyze instability and vibrational modes....

  15. 2008 Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Philip J. Reid

    2009-09-21

    The conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and interfaces. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of systems.

  16. Breaking the fault tree circular logic

    International Nuclear Information System (INIS)

    Lankin, M.

    2000-01-01

    Event tree - fault tree approach to model failures of nuclear plants as well as of other complex facilities is noticeably dominant now. This approach implies modeling an object in form of unidirectional logical graph - tree, i.e. graph without circular logic. However, genuine nuclear plants intrinsically demonstrate quite a few logical loops (circular logic), especially where electrical systems are involved. This paper shows the incorrectness of existing practice of circular logic breaking by elimination of part of logical dependencies and puts forward a formal algorithm, which enables the analyst to correctly model the failure of complex object, which involves logical dependencies between system and components, in form of fault tree. (author)

  17. University Students Alternative Conceptions On Circular Motion

    Directory of Open Access Journals (Sweden)

    Ian Phil Canlas

    2015-08-01

    Full Text Available This study attempted to find out university students alternative conceptions on circular motion. An 18-item researcher-compiled and content-validated questionnaire was administered to twenty-six 26 students taking up a program in Bachelor in Secondary Education-Physical Science in their second year enrolled in a course on mechanics. Results revealed that majority of the students possess alternative conceptions on circular motion specifically along velocity acceleration and force. Moreover results showed the inconsistencies in the students understanding of circular motion concepts.

  18. The Circular Economy between Desiderates and Realities.

    Directory of Open Access Journals (Sweden)

    Tăchiciu Laurentiu

    2018-05-01

    Full Text Available The present issue of Amfiteatru Economic Journal addresses the subject of the circular economy, bringing together research contributions to a better understanding of the current state and perspectives of the adoption of economic and business models conceived to give resources’ highest utility and value in every stage by reducing waste, reusing and recycling. Contributors are approaching the circular economy from different perspectives. Some are concerned with the macroeconomic and social conditions accompanying a higher circularity in the economy, while others focus on businesses’ and individuals’ behaviours.

  19. Vibrational excitation in a hydrogen volume source

    International Nuclear Information System (INIS)

    Eenshuistra, P.J.

    1989-01-01

    In this thesis the complex of processes which determines the D - or H - density in a volume source, a hydrogen discharge, is studied. D - beams are of interest for driving the current of a fusion plasma in a TOKAMAK. Densities of vibrationally excited molecules, of H atoms, and of metastable hydrogen molecules were determined using Resonance-Enhanced MultiPhoton Ionization (REMPI). An experiment in which vibrationally highly excited molecules are formed by recombination of atoms in a cold metal surface, is described. The production and destruction of vibrationally excited molecules and atoms in the discharge is discussed. The vibrational distribution for 3≤ν≤5 (ν = vibrational quantumnumber) is strongly super-thermal. This effect is more apparent at higher discharge current and lower gas pressure. The analysis with a model based on rate equations, which molecules are predominantly produced by primary electron excitation of hydrogen molecules and deexcited upon one wall collision. The atom production is compatible with dissociation of molecules by primary electrons, dissociation of molecules on the filaments, and collisions between positive ions and electrons. The electrons are predominantly destroyed by recombination on the walls. Finally the production and destruction of H - in the discharge are discussed. The density of H - in the plasma, the electron density and temperature were determined. H - extraction was measured. The ratio of the extracted H - current and the H - density in the plasma gives an indication of the drift velocity of H - in the plasma. This velocity determines the emittance of the extracted beam. It was found that the H - velocity scales with the square root of the electron temperature. The measured H - densities are compatible with a qualitative model in which dissociative attachment of plasma electrons to vibrationally excited molecules is the most important process. (author). 136 refs.; 39 figs.; 10 tabs

  20. Tunable plasmonic filter with circular metal–insulator–metal ring ...

    Indian Academy of Sciences (India)

    School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, Jiangsu, China; Paul Scherrer ... The domain part of the email address of all email addresses used by the office of Indian Academy of Sciences, including those of the staff, the journals, various ...

  1. 17 CFR 230.253 - Offering circular.

    Science.gov (United States)

    2010-04-01

    .... Repetition of information should be avoided; cross-referencing of information within the document is... COMPLETENESS OF ANY OFFERING CIRCULAR OR OTHER SELLING LITERATURE. THESE SECURITIES ARE OFFERED PURSUANT TO AN...

  2. 77 FR 42077 - Environmental Justice: Final Circular

    Science.gov (United States)

    2012-07-17

    ..., rulemaking, and policy formulation. The DOT Order sets forth steps to prevent disproportionately high and... Circular as a whole. Some commenters expressed concerns about perceived administrative and financial... Engagement With Environmental Justice Populations Chapter III contains recommended strategies and techniques...

  3. A Conceptual Framework for Circular Design

    Directory of Open Access Journals (Sweden)

    Mariale Moreno

    2016-09-01

    Full Text Available Design has been recognised in the literature as a catalyst to move away from the traditional model of take-make-dispose to achieve a more restorative, regenerative and circular economy. As such, for a circular economy to thrive, products need to be designed for closed loops, as well as be adapted to generate revenues. This should not only be at the point of purchase, but also during use, and be supported by low-cost return chains and reprocessing structures, as well as effective policy and regulation. To date, most academic and grey literature on the circular economy has focused primarily on the development of new business models, with some of the latter studies addressing design strategies for a circular economy, specifically in the area of resource cycles and design for product life extension. However, these studies primarily consider a limited spectrum of the technical and biological cycles where materials are recovered and restored and nutrients (e.g., materials, energy, water are regenerated. This provides little guidance or clarity for designers wishing to design for new circular business models in practice. As such, this paper aims to address this gap by systematically analysing previous literature on Design for Sustainability (DfX (e.g., design for resource conservation, design for slowing resource loops and whole systems design and links these approaches to the current literature on circular business models. A conceptual framework is developed for circular economy design strategies. From this conceptual framework, recommendations are made to enable designers to fully consider the holistic implications for design within a circular economy.

  4. University Students Alternative Conceptions On Circular Motion

    OpenAIRE

    Ian Phil Canlas

    2015-01-01

    This study attempted to find out university students alternative conceptions on circular motion. An 18-item researcher-compiled and content-validated questionnaire was administered to twenty-six 26 students taking up a program in Bachelor in Secondary Education-Physical Science in their second year enrolled in a course on mechanics. Results revealed that majority of the students possess alternative conceptions on circular motion specifically along velocity acceleration and force. Moreover res...

  5. Single particle dynamics in circular accelerators

    International Nuclear Information System (INIS)

    Ruth, R.D.

    1986-10-01

    The purpose of this paper is to introduce the reader to the theory associated with the transverse dynamics of single particle, in circular accelerators. The discussion begins with a review of Hamiltonian dynamics and canonical transformations. The case of a single particle in a circular accelerator is considered with a discussion of non-linear terms and chromaticity. The canonical perturbation theory is presented and nonlinear resonances are considered. Finally, the concept of renormalization and residue criterion are examined. (FI)

  6. Asymptotic theory of circular polarization memory.

    Science.gov (United States)

    Dark, Julia P; Kim, Arnold D

    2017-09-01

    We establish a quantitative theory of circular polarization memory, which is the unexpected persistence of the incident circular polarization state in a strongly scattering medium. Using an asymptotic analysis of the three-dimensional vector radiative transfer equation (VRTE) in the limit of strong scattering, we find that circular polarization memory must occur in a boundary layer near the portion of the boundary on which polarized light is incident. The boundary layer solution satisfies a one-dimensional conservative scattering VRTE. Through a spectral analysis of this boundary layer problem, we introduce the dominant mode, which is the slowest-decaying mode in the boundary layer. To observe circular polarization memory for a particular set of optical parameters, we find that this dominant mode must pass three tests: (1) this dominant mode is given by the largest, discrete eigenvalue of a reduced problem that corresponds to Fourier mode k=0 in the azimuthal angle, and depends only on Stokes parameters U and V; (2) the polarization state of this dominant mode is largely circular polarized so that |V|≫|U|; and (3) the circular polarization of this dominant mode is maintained for all directions so that V is sign-definite. By applying these three tests to numerical calculations for monodisperse distributions of Mie scatterers, we determine the values of the size and relative refractive index when circular polarization memory occurs. In addition, we identify a reduced, scalar-like problem that provides an accurate approximation for the dominant mode when circular polarization memory occurs.

  7. Unleashing the Power of the Circular Economy

    Energy Technology Data Exchange (ETDEWEB)

    Kok, L.; Wurpel, G.; Ten Wolde, A. [IMSA Amsterdam, Amsterdam (Netherlands)

    2013-04-15

    The concept of circular economy is an economic and industrial system that focuses on the reusability of products and raw materials, reduces value destruction in the overall system and aims at value creation within each tier of the system. This report for Circle Economy (CE) outlines the general direction and concrete steps that must be taken to accomplish a breakthrough to a circular economy. It also provides a knowledge base behind the concept, connecting it to sustainability.

  8. Breaking the Barriers to the Circular Economy

    OpenAIRE

    Kirchherr, J.W.; Hekkert, M.P.; Bour, Ruben; Huijbrechtse-Truijens, Anne; Kostense-Smit, Erica; Muller, Jennifer

    2017-01-01

    The Copernicus Institute of Sustainable Development, Utrecht University, the Netherlands and Deloitte have jointly carried out research on barriers to the Circular Economy (CE) in the European Union. For this research, a survey with 153 businesses, 55 government officials and expert interviews with forty-seven thought leaders on the circular economy from businesses, governments, academia and NGOs have been carried out. Two types of barriers emerged as main barriers Firstly, there are the cult...

  9. An analytical study of the effects of transverse shear deformation and anisotropy on natural vibration frequencies of laminated cylinders

    Science.gov (United States)

    Jegley, Dawn C.

    1988-01-01

    Natural vibration frequencies of orthotropic and anisotropic simply supported right circular cylinders are predicted using a higher-order transverse-shear deformation theory. A comparison of natural vibration frequencies predicted by first-order transverse-shear deformation theory and the higher-order theory shows that an additional allowance for transverse shear deformation has a negligible effect on the lowest predicted natural vibration frequencies of laminated cylinders but significantly reduces the higher natural vibration frequencies. A parametric study of the effects of ply orientation on the natural vibration frequencies of laminated cylinders indicates that while stacking sequence affects natural vibration frequencies, cylinder geometry is more important in predicting transverse-shear deformation effects. Interaction curves for cylinders subjected to axial compressive loadings and low natural vibration frequencies indicate that transverse shearing effects are less important in predicting low natural vibration frequencies than in predicting axial compressive buckling loads. The effects of anisotropy are more important than the effects of transverse shear deformation for most strongly anisotropic laminated cylinders in predicting natural vibration frequencies. However, transverse-shear deformation effects are important in predicting high natural vibration frequencies of thick-walled laminated cylinders. Neglecting either anisotropic effects or transverse-shear deformation effects leads to non-conservative errors in predicted natural vibration frequencies.

  10. Three-dimensional Reconstruction Method Study Based on Interferometric Circular SAR

    Directory of Open Access Journals (Sweden)

    Hou Liying

    2016-10-01

    Full Text Available Circular Synthetic Aperture Radar (CSAR can acquire targets’ scattering information in all directions by a 360° observation, but a single-track CSAR cannot efficiently obtain height scattering information for a strong directive scatter. In this study, we examine the typical target of the three-dimensional circular SAR interferometry theoryand validate the theory in a darkroom experiment. We present a 3D reconstruction of the actual tank metal model of interferometric CSAR for the first time, verify the validity of the method, and demonstrate the important potential applications of combining 3D reconstruction with omnidirectional observation.

  11. Circular codes revisited: a statistical approach.

    Science.gov (United States)

    Gonzalez, D L; Giannerini, S; Rosa, R

    2011-04-21

    In 1996 Arquès and Michel [1996. A complementary circular code in the protein coding genes. J. Theor. Biol. 182, 45-58] discovered the existence of a common circular code in eukaryote and prokaryote genomes. Since then, circular code theory has provoked great interest and underwent a rapid development. In this paper we discuss some theoretical issues related to the synchronization properties of coding sequences and circular codes with particular emphasis on the problem of retrieval and maintenance of the reading frame. Motivated by the theoretical discussion, we adopt a rigorous statistical approach in order to try to answer different questions. First, we investigate the covering capability of the whole class of 216 self-complementary, C(3) maximal codes with respect to a large set of coding sequences. The results indicate that, on average, the code proposed by Arquès and Michel has the best covering capability but, still, there exists a great variability among sequences. Second, we focus on such code and explore the role played by the proportion of the bases by means of a hierarchy of permutation tests. The results show the existence of a sort of optimization mechanism such that coding sequences are tailored as to maximize or minimize the coverage of circular codes on specific reading frames. Such optimization clearly relates the function of circular codes with reading frame synchronization. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Energetically efficient proportional-integral-differential (PID) control of wake vortices behind a circular cylinder

    International Nuclear Information System (INIS)

    Das, Pramode K; Mathew, Sam; Shaiju, A J; Patnaik, B S V

    2016-01-01

    The control of vortex shedding behind a circular cylinder is a precursor to a wide range of external shear flow problems in engineering, in particular the flow-induced vibrations. In the present study, numerical simulation of an energetically efficient active flow control strategy is proposed, for the control of wake vortices behind a circular cylinder at a low Reynolds number of 100. The fluid is assumed to be incompressible and Newtonian with negligible variation in properties. Reflectionally symmetric controllers are designed such that, they are located on a small sector of the cylinder over which, tangential sliding mode control is imparted. In the field of modern controls, proportional (P), integral (I) and differential (D) control strategies and their numerous combinations are extremely popular in industrial practice. To impart suitable control actuation, the vertically varying lift force on the circular cylinder, is synthesised for the construction of an error term. Four different types of controllers considered in the present study are, P, I, PI and PID. These controllers are evaluated for their energetic efficiency and performance. A linear quadratic optimal control problem is formulated, to minimise the cost functional. By performing detailed simulations, it was observed that, the system is energetically efficient, even when the twin eddies are still persisting behind the circular cylinder. To assess the adaptability of the controllers, the actuators were switched on and off to study their dynamic response. (paper)

  13. Vibration transducer calibration techniques

    Science.gov (United States)

    Brinkley, D. J.

    1980-09-01

    Techniques for the calibration of vibration transducers used in the Aeronautical Quality Assurance Directorate of the British Ministry of Defence are presented. Following a review of the types of measurements necessary in the calibration of vibration transducers, the performance requirements of vibration transducers, which can be used to measure acceleration, velocity or vibration amplitude, are discussed, with particular attention given to the piezoelectric accelerometer. Techniques for the accurate measurement of sinusoidal vibration amplitude in reference-grade transducers are then considered, including the use of a position sensitive photocell and the use of a Michelson laser interferometer. Means of comparing the output of working-grade accelerometers with that of previously calibrated reference-grade devices are then outlined, with attention given to a method employing a capacitance bridge technique and a method to be used at temperatures between -50 and 200 C. Automatic calibration procedures developed to speed up the calibration process are outlined, and future possible extensions of system software are indicated.

  14. Nonlinear dynamics of a circular piezoelectric plate for vibratory energy harvesting

    Science.gov (United States)

    Yuan, Tian-Chen; Yang, Jian; Chen, Li-Qun

    2018-06-01

    Nonlinear behaviors are investigated for a vibration-based energy harvester. The harvester consists of a circular composite plate with the clamped boundary, a proof mass and two steel rings. The lumped parameter model of the harvester is established and the parameters are identified from the experiment. The measured nonlinear behaviors can be approximately described by the lumped model. Both the experimental and the numerical results demonstrate that the circular plate harvester has soft characteristics under low excitation and both hard characteristics and soft characteristics under high excitation. The experimental results show that the output voltage can achieve over 35 V (about 50 mW) and more than 14 Hz of bandwidth with 25 kΩ load resistance.

  15. Mathematical modeling and calculation of forced resonant vibrations of composite electromechanical system

    OpenAIRE

    Ластівка, Іван Олексійович

    2014-01-01

    Resonant vibrations of composite electromechanical symmetric three-element system “metal plate - piezoceramic cylindrical panels” are considered. Forced vibrations are made under the influence of external alternating electric field, supplied to the electrodes of piezoceramic segments of cylindrical panels, previously polarized in the tangential direction.Based on the improved theory, such as the S.P. Timoshenko’s, the system of differential equations of forced vibrations of the system, taking...

  16. DETERMINATION OF CRITICAL ROTATIONAL SPEED OF CIRCULAR SAWS FROM NATURAL FREQUENCIES OF ANNULAR PLATE WITH ANALOGOUS DIMENSIONS

    Directory of Open Access Journals (Sweden)

    Ante Skoblar

    2016-03-01

    Full Text Available It is suitable to reduce thickness of circular saw when trying to enhance usability of wood raw material, but reducing thickness also causes reduction of permissible rotational speed which reduces sawing speed. If one increase circular saw rotational speed over permissible one the quality of machined surfaces will reduce because of enhanced vibrations. Permissible rotational speed can be calculated from critical rotational speed which can be defined from natural frequencies of the saw. In this article critical rotational speeds of standard clamped saws (with flat disk surface and without slots are calculated by using finite element method and classical theory of thin plates on annular plates. Mode shapes and natural frequencies of annular plates are determined by using Bessel functions and by using polynomial functions. Obtained results suggest that standard clamped circular saws without slots and with relatively small teeth can be determined from classical theory of thin plates for annular plates with accuracy depending on clamping ratio.

  17. Recovering Intrinsic Fragmental Vibrations Using the Generalized Subsystem Vibrational Analysis.

    Science.gov (United States)

    Tao, Yunwen; Tian, Chuan; Verma, Niraj; Zou, Wenli; Wang, Chao; Cremer, Dieter; Kraka, Elfi

    2018-05-08

    Normal vibrational modes are generally delocalized over the molecular system, which makes it difficult to assign certain vibrations to specific fragments or functional groups. We introduce a new approach, the Generalized Subsystem Vibrational Analysis (GSVA), to extract the intrinsic fragmental vibrations of any fragment/subsystem from the whole system via the evaluation of the corresponding effective Hessian matrix. The retention of the curvature information with regard to the potential energy surface for the effective Hessian matrix endows our approach with a concrete physical basis and enables the normal vibrational modes of different molecular systems to be legitimately comparable. Furthermore, the intrinsic fragmental vibrations act as a new link between the Konkoli-Cremer local vibrational modes and the normal vibrational modes.

  18. Vibrations in orthopedics.

    Science.gov (United States)

    Nokes, L D; Thorne, G C

    1988-01-01

    Measurements of various mechanical properties of skeletal material using vibration techniques have been reported. The purposes of such investigations include the monitoring of pathogenic disorders such as osteoporosis, the rate and extent of fracture healing, and the status of internal fixations. Early investigations pioneered the application of conventional vibration measurement equipment to biological systems. The more recent advent of the microcomputer has made available to research groups more sophisticated techniques for data acquisition and analysis. The economical advantages of such equipment has led to the development of portable research instrumentation which lends itself to use in a clinical environment. This review article reports on the developments and progression of the various vibrational techniques and theories as applied to musculoskeletal systems.

  19. Optical rectification, circular photogalvanic effect, and five-wave mixing in optically active liquids

    Science.gov (United States)

    Koroteev, Nikolai I.

    1996-05-01

    A phenomenological analysis is carried out of novel nonlinear optical processes taking place in macroscopically noncentrosymmetric isotropic solutions of chiral (lift-ring mirror asymmetric) macromolecules, which are the primary elements of living organisms and their metabolic products. Among the most interesting and potentially useful for spectroscopic purposes are: optical rectification/photogalvanic effects consisting in electrostatic field/direct electrical current generation in such liquids under irradiation with the intense circularly polarized laser beam and the five-wave mixing phase-matched process of BioCARS to selectively record, background-free, vibrational spectra of chiral molecules.

  20. Vibrational spectra of aminoacetonitrile

    International Nuclear Information System (INIS)

    Bak, B.; Hansen, E.L.; Nicolaisen, F.M.; Nielsen, O.F.

    1975-01-01

    The preparation of pure, stable aminoacetonitrile(1-amino, 1'-cyanomethane)CH 2 NH 2 CN (1) is described. The Raman spectrum, now complete, and a novel infrared spectrum extending over the 50-3600 cm -1 region are reported. A tentative normal vibration analysis is presented and supported by Raman and infrared data from the spectra of CH 2 NHDCN (2) and CH 2 ND 2 CN (3). The predominance of the trans rotamer may be attributed to intramolecular hydrogen bonding but this is too unimportant to influence the vibrational frequencies of gaseous 1, 2, and 3. However, large gas/liquid frequency shifts occur. (author)

  1. Vibrations and waves

    CERN Document Server

    Kaliski, S

    2013-01-01

    This book gives a comprehensive overview of wave phenomena in different media with interacting mechanical, electromagnetic and other fields. Equations describing wave propagation in linear and non-linear elastic media are followed by equations of rheological models, models with internal rotational degrees of freedom and non-local interactions. Equations for coupled fields: thermal, elastic, electromagnetic, piezoelectric, and magneto-spin with adequate boundary conditions are also included. Together with its companion volume Vibrations and Waves. Part A: Vibrations this work provides a wealth

  2. Vibration Theory, Vol. 3

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

    The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 2nd edition of this textbook on linear stochastic vibration th...... theory is basically unchanged in comparison to the 1st edition. Only section 4.2 on single input - single output systems and chapter 6 on offshore structures have been modified in order to enhance the clearness....

  3. Cygnus X-1: Discovery of variable circular polarization

    International Nuclear Information System (INIS)

    Michalsky, J.J.; Swedlund, J.B.; Stokes, R.A.

    1975-01-01

    HDE 226868, the optical counterpart of Cyg X-1, has been observed for circular polarization during 1974. Observations in five colors suggest that circular polarization results from an interstellar effect. Measurements of the blue polarization reveal circular polarization variations synchronous with the 5)./sub /6 orbital period. The circular polarization variation appears to be similar to the blue intensity variation

  4. Heterogeneous Dynamics of Coupled Vibrations

    NARCIS (Netherlands)

    Cringus, Dan; Jansen, Thomas I. C.; Pshenichnikov, Maxim S.; Schoenlein, RW; Corkum, P; DeSilvestri, S; Nelson, KA; Riedle, E

    2009-01-01

    Frequency-dependent dynamics of coupled stretch vibrations of a water molecule are revealed by 2D IR correlation spectroscopy. These are caused by non-Gaussian fluctuations of the environment around the individual OH stretch vibrations.

  5. Vibration in car repair work.

    Science.gov (United States)

    Hansson, J E; Eklund, L; Kihlberg, S; Ostergren, C E

    1987-03-01

    The main objective of the study was to find efficient hand tools which caused only minor vibration loading. Vibration measurements were carried out under standardised working conditions. The time during which car body repairers in seven companies were exposed to vibration was determined. Chisel hammers, impact wrenches, sanders and saws were the types of tools which generated the highest vibration accelerations. The average daily exposure at the different garages ranged from 22 to 70 min. The risk of vibration injury is currently rated as high. The difference between the highest and lowest levels of vibration was considerable in most tool categories. Therefore the choice of tool has a major impact on the magnitude of vibration exposure. The importance of choosing the right tools and working methods is discussed and a counselling service on vibration is proposed.

  6. Circularly polarized light emission in scanning tunneling microscopy of magnetic systems

    International Nuclear Information System (INIS)

    Apell, S.P.; Penn, D.R.; Johansson, P.

    2000-01-01

    Light is produced when a scanning tunneling microscope is used to probe a metal surface. Recent experiments on cobalt utilizing a tungsten tip found that the light is circularly polarized; the sense of circular polarization depends on the direction of the sample magnetization, and the degree of polarization is of order 10%. This raises the possibility of constructing a magnetic microscope with very good spatial resolution. We present a theory of this effect for iron and cobalt and find a degree of polarization of order 0.1%. This is in disagreement with the experiments on cobalt as well as previous theoretical work which found order of magnitude agreement with the experimental results. However, a recent experiment on iron showed 0.0±2%. We predict that the use of a silver tip would increase the degree of circular polarization for a range of photon energies

  7. Total and Differential Efficiencies for a Circular Detector Viewing a Circular Radiator of Finite Thickness

    Energy Technology Data Exchange (ETDEWEB)

    Lauber, A; Tollander, B

    1967-08-15

    Total and differential detection efficiencies have been computed for a circular detector viewing a circular radiator of finite thickness. Isotropic, cosines and n-p scattering angular emission distributions of the radiated particles are considered. Tables are given for the total efficiencies as well as for the differential efficiencies in the n-p scattering case.

  8. Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism.

    Science.gov (United States)

    Fan, Tingting; Grychtol, Patrik; Knut, Ronny; Hernández-García, Carlos; Hickstein, Daniel D; Zusin, Dmitriy; Gentry, Christian; Dollar, Franklin J; Mancuso, Christopher A; Hogle, Craig W; Kfir, Ofer; Legut, Dominik; Carva, Karel; Ellis, Jennifer L; Dorney, Kevin M; Chen, Cong; Shpyrko, Oleg G; Fullerton, Eric E; Cohen, Oren; Oppeneer, Peter M; Milošević, Dejan B; Becker, Andreas; Jaroń-Becker, Agnieszka A; Popmintchev, Tenio; Murnane, Margaret M; Kapteyn, Henry C

    2015-11-17

    We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.

  9. The Study the Vibration Condition of the Blade of the Gas Turbine Engine with an All-metal Wire Rope Damper in the Area Mount of the Blade to the Disk

    Science.gov (United States)

    Melentjev, Vladimir S.; Gvozdev, Alexander S.

    2018-01-01

    Improving the reliability of modern turbine engines is actual task. This is achieved due to prevent a vibration damage of the operating blades. On the department of structure and design of aircraft engines have accumulated a lot of experimental data on the protection of the blades of the gas turbine engine from a vibration. In this paper we proposed a method for calculating the characteristics of wire rope dampers in the root attachment of blade of a gas turbine engine. The method is based on the use of the finite element method and transient analysis. Contact interaction (Lagrange-Euler method) between the compressor blade and the disc of the rotor has been taken into account. Contribution of contact interaction between details in damping of the system was measured. The proposed method provides a convenient way for the iterative selection of the required parameters the wire rope elastic-damping element. This element is able to provide the necessary protection from the vibration for the blade of a gas turbine engine.

  10. Environmental issues elimination through circular economy

    International Nuclear Information System (INIS)

    Špirková, M.; Pokorná, E.; Šujanová, J.; Samáková, J.

    2016-01-01

    Environmental efforts of European Union are currently going towards circular economy. Tools like Extended Producer Responsibility and Eco-design were established. The circular economy deals with resources availability issue on one hand and waste management on the other hand. There are few pioneering companies all over the world with some kind of circular economy practice. Generally the concept is not very wide-spread. The paper aims to evaluate possibility of transition towards circular economy in Slovak industrial companies. They need to have an active approach to material treatment of their products after usage stage. Innovation is another important pre-condition for the transition. Main problem of current cradle to grave system is landfilling of valuable materials after one cycle of usage. Their potential value for next manufacturing cycles is lost. Companies may do not see connection between waste management and material resource prices and volatility of supplies. Municipalities are responsible for municipal waste collection and treatment in Slovakia. The circular economy operates by cradle to cradle principle. Company manages material flow until the material comes back to the beginning of manufacturing process by itself or by another partners. Stable material supplies with quite low costs are provided this way. It is necessary to deal with environmental problems in phase of product design. Questionnaire survey results show on one hand low involvement of industrial companies in waste management area, however on the other hand they are open to environmental innovations in future.

  11. Environmental issues elimination through circular economy

    Energy Technology Data Exchange (ETDEWEB)

    Špirková, M., E-mail: marta.spirkova@stuba.sk; Pokorná, E.; Šujanová, J.; Samáková, J. [Paulínska 16, 917 24 Trnava, Slovakia, Slovak University of Technology in Bratislava, Faculty of Materials Science and Technology in Trnava (Slovakia)

    2016-04-21

    Environmental efforts of European Union are currently going towards circular economy. Tools like Extended Producer Responsibility and Eco-design were established. The circular economy deals with resources availability issue on one hand and waste management on the other hand. There are few pioneering companies all over the world with some kind of circular economy practice. Generally the concept is not very wide-spread. The paper aims to evaluate possibility of transition towards circular economy in Slovak industrial companies. They need to have an active approach to material treatment of their products after usage stage. Innovation is another important pre-condition for the transition. Main problem of current cradle to grave system is landfilling of valuable materials after one cycle of usage. Their potential value for next manufacturing cycles is lost. Companies may do not see connection between waste management and material resource prices and volatility of supplies. Municipalities are responsible for municipal waste collection and treatment in Slovakia. The circular economy operates by cradle to cradle principle. Company manages material flow until the material comes back to the beginning of manufacturing process by itself or by another partners. Stable material supplies with quite low costs are provided this way. It is necessary to deal with environmental problems in phase of product design. Questionnaire survey results show on one hand low involvement of industrial companies in waste management area, however on the other hand they are open to environmental innovations in future.

  12. Environmental issues elimination through circular economy

    Science.gov (United States)

    Špirková, M.; Pokorná, E.; Šujanová, J.; Samáková, J.

    2016-04-01

    Environmental efforts of European Union are currently going towards circular economy. Tools like Extended Producer Responsibility and Eco-design were established. The circular economy deals with resources availability issue on one hand and waste management on the other hand. There are few pioneering companies all over the world with some kind of circular economy practice. Generally the concept is not very wide-spread. The paper aims to evaluate possibility of transition towards circular economy in Slovak industrial companies. They need to have an active approach to material treatment of their products after usage stage. Innovation is another important pre-condition for the transition. Main problem of current cradle to grave system is landfilling of valuable materials after one cycle of usage. Their potential value for next manufacturing cycles is lost. Companies may do not see connection between waste management and material resource prices and volatility of supplies. Municipalities are responsible for municipal waste collection and treatment in Slovakia. The circular economy operates by cradle to cradle principle. Company manages material flow until the material comes back to the beginning of manufacturing process by itself or by another partners. Stable material supplies with quite low costs are provided this way. It is necessary to deal with environmental problems in phase of product design. Questionnaire survey results show on one hand low involvement of industrial companies in waste management area, however on the other hand they are open to environmental innovations in future.

  13. Energy Harvester Based on the Synchronization Phenomenon of a Circular Cylinder

    Directory of Open Access Journals (Sweden)

    Junlei Wang

    2014-01-01

    Full Text Available A concept of generating power from a circular cylinder undergoing vortex-induced vibration (VIV was investigated. Two lead zirconate titanate (PZT beams which had high power density were installed on the cylinder. A theoretical model has been presented to describe the electromechanical coupling of the open-circuit voltage output and the vibration amplitudes based on a second-order nonlinear Van der pol equation and Gauss law. A numerical computation was applied to measure the capacity of the power generating system. The lift and drag coefficient and the vortex shedding frequency were obtained to verify how the nondimensional parameter reduced velocity Ur affects the fluid field. Meanwhile, a single-degree of freedom system has been added to describe the VIV, presynchronization, and synchronization together with postsynchronization regimes of oscillating frequencies. And the amplitudes of the vibration have been obtained. Finally, the vibrational amplitudes and the voltage output could go up to a high level in the synchronization region. The maximum value of the voltage output and the corresponding reduced velocity Ur were 8.42 V and 5.6, respectively.

  14. Structural Stability and Vibration

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Pedersen, Pauli

    at the University of Southern Denmark, it reports on fundamental formulas and makes uses of graphical representation to promote understanding. Thanks to the emphasis put on analytical methods and numerical results, the book is meant to make students and engineers familiar with all fundamental equations...... and their derivation, thus stimulating them to write interactive and dynamic programs to analyze instability and vibrational modes....

  15. Vibrational Spectroscopy and Astrobiology

    Science.gov (United States)

    Chaban, Galina M.; Kwak, D. (Technical Monitor)

    2001-01-01

    Role of vibrational spectroscopy in solving problems related to astrobiology will be discussed. Vibrational (infrared) spectroscopy is a very sensitive tool for identifying molecules. Theoretical approach used in this work is based on direct computation of anharmonic vibrational frequencies and intensities from electronic structure codes. One of the applications of this computational technique is possible identification of biological building blocks (amino acids, small peptides, DNA bases) in the interstellar medium (ISM). Identifying small biological molecules in the ISM is very important from the point of view of origin of life. Hybrid (quantum mechanics/molecular mechanics) theoretical techniques will be discussed that may allow to obtain accurate vibrational spectra of biomolecular building blocks and to create a database of spectroscopic signatures that can assist observations of these molecules in space. Another application of the direct computational spectroscopy technique is to help to design and analyze experimental observations of ice surfaces of one of the Jupiter's moons, Europa, that possibly contains hydrated salts. The presence of hydrated salts on the surface can be an indication of a subsurface ocean and the possible existence of life forms inhabiting such an ocean.

  16. Vibrations and Eigenvalues

    Indian Academy of Sciences (India)

    The vibrating string problem is the source of much mathe- matics and physics. ... ing this science [mechanics],and the art of solving the problems pertaining to it, to .... used tools for finding maxima and minima of functions of several variables.

  17. Heat exchanger vibration

    International Nuclear Information System (INIS)

    Richards, D.J.W.

    1977-01-01

    The heat exchangers of various types are common items of plant in the generation and transmission of electricity. The amount of attention given to the flow-induced vibrations of heat exchangers by designers is usually related to the operational history of similar items of plant. Consequently, if a particular design procedure yields items of plant which behave in a satisfactory manner during their operational life, there is little incentive to improve or refine the design procedure. On the other hand, failures of heat exchangers clearly indicate deficiencies in the design procedures or in the data available to the designer. When such failures are attributable to flow-induced vibrations, the identification of the mechanisms involved is a prime importance. Ideally, basic research work provides the background understanding and the techniques necessary to be able to identify the important mechanisms. In practice, the investigation of a flow-induced vibration problem may identify the presence of mechanisms but may not be able to quantify their effects adequately. In these circumstances the need for additional work is established and the objectives of the research programme emerge. The purpose of this paper is to outline the background to the current research programme at C.E.R.L. on heat exchanger vibration

  18. Man-Induced Vibrations

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Hansen, Lars Pilegaard

    1994-01-01

    work has been done on the measurement of the exact load functions and related reponse analysis. A recent work using a spectral description has been performed by Per-Erik Erikson and includes a good literature survey. Bachmann and Ammann give a good overview of vibrations caused by human activity. Other...

  19. Heat exchanger vibration

    Energy Technology Data Exchange (ETDEWEB)

    Richards, D J.W. [CERL, CEGB, Leatherhead, Surrey (United Kingdom)

    1977-12-01

    The heat exchangers of various types are common items of plant in the generation and transmission of electricity. The amount of attention given to the flow-induced vibrations of heat exchangers by designers is usually related to the operational history of similar items of plant. Consequently, if a particular design procedure yields items of plant which behave in a satisfactory manner during their operational life, there is little incentive to improve or refine the design procedure. On the other hand, failures of heat exchangers clearly indicate deficiencies in the design procedures or in the data available to the designer. When such failures are attributable to flow-induced vibrations, the identification of the mechanisms involved is a prime importance. Ideally, basic research work provides the background understanding and the techniques necessary to be able to identify the important mechanisms. In practice, the investigation of a flow-induced vibration problem may identify the presence of mechanisms but may not be able to quantify their effects adequately. In these circumstances the need for additional work is established and the objectives of the research programme emerge. The purpose of this paper is to outline the background to the current research programme at C.E.R.L. on heat exchanger vibration.

  20. General principles of vibrational spectroscopies

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Schoonheydt, R.A.

    2000-01-01

    Atoms in molecules and solids do not remain in fixed relative positions, but vibrate about some mean position. This vibrational motion is quantized and at room temperature, most of the molecules in a given sample are in their lowest vibrational state. Absorption of electromagnetic radiation with

  1. High-Temperature Vibration Damper

    Science.gov (United States)

    Clarke, Alan; Litwin, Joel; Krauss, Harold

    1987-01-01

    Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.

  2. Ferroelastic ceramic-reinforced metal matrix composites

    OpenAIRE

    2006-01-01

    Composite materials comprising ferroelastic ceramic particulates dispersed in a metal matrix are capable of vibration damping. When the ferroelastic ceramic particulates are subjected to stress, such as the cyclic stress experienced during vibration of the material, internal stresses in the ceramic cause the material to deform via twinning, domain rotation or domain motion thereby dissipating the vibrational energy. The ferroelastic ceramic particulates may also act as reinforcements to impro...

  3. Wireless Inductive Power Device Suppresses Blade Vibrations

    Science.gov (United States)

    Morrison, Carlos R.; Provenza, Andrew J.; Choi, Benjamin B.; Bakhle, Milind A.; Min, James B.; Stefko, George L.; Duffy, Kirsten P.; Fougers, Alan J.

    2011-01-01

    Vibration in turbomachinery can cause blade failures and leads to the use of heavier, thicker blades that result in lower aerodynamic efficiency and increased noise. Metal and/or composite fatigue in the blades of jet engines has resulted in blade destruction and loss of lives. Techniques for suppressing low-frequency blade vibration, such as gtuned circuit resistive dissipation of vibratory energy, h or simply "passive damping," can require electronics incorporating coils of unwieldy dimensions and adding unwanted weight to the rotor. Other approaches, using vibration-dampening devices or damping material, could add undesirable weight to the blades or hub, making them less efficient. A wireless inductive power device (WIPD) was designed, fabricated, and developed for use in the NASA Glenn's "Dynamic Spin Rig" (DSR) facility. The DSR is used to simulate the functionality of turbomachinery. The relatively small and lightweight device [10 lb (approx.=4.5 kg)] replaces the existing venerable and bulky slip-ring. The goal is the eventual integration of this technology into actual turbomachinery such as jet engines or electric power generators, wherein the device will facilitate the suppression of potentially destructive vibrations in fan blades. This technology obviates slip rings, which require cooling and can prove unreliable or be problematic over time. The WIPD consists of two parts: a remote element, which is positioned on the rotor and provides up to 100 W of electrical power to thin, lightweight piezoelectric patches strategically placed on/in fan blades; and a stationary base unit that wirelessly communicates with the remote unit. The base unit supplies inductive power, and also acts as an input and output corridor for wireless measurement, and active control command to the remote unit. Efficient engine operation necessitates minimal disturbance to the gas flow across the turbine blades in any effort to moderate blade vibration. This innovation makes it

  4. Optics modules for circular accelerator design

    International Nuclear Information System (INIS)

    Brown, K.L.; Servranckx, R.V.

    1986-05-01

    The first-order differential equations of motion for a single particle in a closed circular machine are solved, introducing the concepts of phase shift, beta functions, and the Courant-Snyder invariant. The transfer matrix between two points in the machine is derived as a function of the phase shift and the parameters contained in the Courant-Snyder invariant. Typical optical modules used in circular machine designs are introduced and related to their characteristic transfer matrix elements, the phase shift through them, and the Courant-Snyder-Twiss parameters. The systematics of some elementary phase ellipse matching problems between optical modules are discussed. Second-order optical modules are discussed, including how they are used to provide the momentum bandwidth needed for the design of a typical circular machine

  5. Equatorial circular motion in Kerr spacetime

    International Nuclear Information System (INIS)

    Pugliese, Daniela; Quevedo, Hernando; Ruffini, Remo

    2011-01-01

    We analyze the properties of circular orbits of test particles on the equatorial plane of a rotating central mass whose gravitational field is described by the Kerr spacetime. For rotating black holes and naked singularities we explore all the spatial regions where circular orbits can exist and analyze the behavior of the energy and the angular momentum of the corresponding test particles. In particular, we find all the radii at which a test particle can have zero angular momentum due to the repulsive gravity effects generated by naked singularities. We classify all the stability zones of circular orbits. It is shown that the geometric structure of the stability zones of black holes is completely different from that of naked singularities.

  6. Circular economy and waste to energy

    Science.gov (United States)

    Rada, E. C.; Ragazzi, M.; Torretta, V.; Castagna, G.; Adami, L.; Cioca, L. I.

    2018-05-01

    Waste management in European Union has long being regulated by the 4Rs principle, i.e. reduction, reuse, recycling, recovery, with landfill disposal as the last option. This vision recently led the European Union (especially since 2015) to the introduction of virtuous goals based on the rejection of linear economy in favour of circular economy strongly founded on materials recovery. In this scenario, landfill disposal option will disappear, while energy recovery may appear controversial when not applied to biogas production from anaerobic digestion. The present work aims to analyse the effects that circular economy principles introduced in the European Union context will have on the thermochemical waste treatment plants design. Results demonstrate that indirect combustion (gasification + combustion) along with integrated vitrification of the non-combustible fraction of treated waste will have a more relevant role in the field of waste treatment than in the past, thanks to the compliance of this option with the principles of circular economy.

  7. Vibration improved the fluidity of aluminum alloys in thin wall ...

    African Journals Online (AJOL)

    user

    The technique to "increase" the metal head during casting and improve the ... The effect of vibration is quantified and incorporated into the fluidity model, such that the ..... Deformation, caused by the expansion and contraction of the thin skin of ...

  8. Ag(I)-mediated homo and hetero pairs of guanosine and cytidine: monitoring by circular dichroism spectroscopy.

    Science.gov (United States)

    Goncharova, Iryna

    2014-01-24

    Ag(I)-containing compounds are attractive as antibacterial and antifungal agents. The renewed interest in the application of silver(I) compounds has led to the need for detailed knowledge of the mechanism of their action. One of the possible ways is the coordination of Ag(I) to G-C pairs of DNA, where Ag(+) ions form Ag(I)-mediated base pairs and inhibit the transcription. Herein, a systematic chiroptical study on silver(I)-mediated homo and mixed pairs of the C-G complementary-base derivatives cytidine(C) and 5'-guanosine monophosphate(G) in water is presented. Ag(I)-mediated homo and hetero pairs of G and C and their self-assembled species were studied under two pH levels (7.0 and 10.0) by vibrational (VCD) and electronic circular dichroism(ECD). VCD was used for the first time in this field and showed itself to be a powerful method for obtaining specific structural information in solution. Based on results of the VCD experiments, the different geometries of the homo pairs were proposed under pH 7.0 and 10.0. ECD was used as a diagnostic tool to characterize the studied systems and as a contact point between the previously defined structures of the metal or proton mediated pairs of nucleobases and the systems studied here. On the basis of the obtained data, the formation of the self-assembled species of cytidine with a structure similar to the i-motif structure in DNA was proposed at pH 10.0. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. METHOD OF CONJUGATED CIRCULAR ARCS TRACING

    Directory of Open Access Journals (Sweden)

    N. Ageyev Vladimir

    2017-01-01

    Full Text Available The geometric properties of conjugated circular arcs connecting two points on the plane with set directions of tan- gent vectors are studied in the work. It is shown that pairs of conjugated circular arcs with the same conditions in frontier points create one-parameter set of smooth curves tightly filling all the plane. One of the basic properties of this set is the fact that all coupling points of circular arcs are on the circular curve going through the initially given points. The circle radius depends on the direction of tangent vectors. Any point of the circle curve, named auxiliary in this work, determines a pair of conjugated arcs with given boundary conditions. One more condition of the auxiliary circle curve is that it divides the plane into two parts. The arcs going from the initial point are out of the circle limited by this circle curve and the arcs coming to the final point are inside it. These properties are the basis for the method of conjugated circular arcs tracing pro- posed in this article. The algorithm is rather simple and allows to fulfill all the needed plottings using only the divider and ruler. Two concrete examples are considered. The first one is related to the problem of tracing of a pair of conjugated arcs with the minimal curve jump when going through the coupling point. The second one demonstrates the possibility of trac- ing of the smooth curve going through any three points on the plane under condition that in the initial and final points the directions of tangent vectors are given. The proposed methods of conjugated circular arcs tracing can be applied in solving of a wide variety of problems connected with the tracing of cam contours, for example pattern curves in textile industry or in computer-aided-design systems when programming of looms with numeric control.

  10. The effects of vibration-reducing gloves on finger vibration

    Science.gov (United States)

    Welcome, Daniel E.; Dong, Ren G.; Xu, Xueyan S.; Warren, Christopher; McDowell, Thomas W.

    2015-01-01

    Vibration-reducing (VR) gloves have been used to reduce the hand-transmitted vibration exposures from machines and powered hand tools but their effectiveness remains unclear, especially for finger protection. The objectives of this study are to determine whether VR gloves can attenuate the vibration transmitted to the fingers and to enhance the understanding of the mechanisms of how these gloves work. Seven adult male subjects participated in the experiment. The fixed factors evaluated include hand force (four levels), glove condition (gel-filled, air bladder, no gloves), and location of the finger vibration measurement. A 3-D laser vibrometer was used to measure the vibrations on the fingers with and without wearing a glove on a 3-D hand-arm vibration test system. This study finds that the effect of VR gloves on the finger vibration depends on not only the gloves but also their influence on the distribution of the finger contact stiffness and the grip effort. As a result, the gloves increase the vibration in the fingertip area but marginally reduce the vibration in the proximal area at some frequencies below 100 Hz. On average, the gloves reduce the vibration of the entire fingers by less than 3% at frequencies below 80 Hz but increase at frequencies from 80 to 400 Hz. At higher frequencies, the gel-filled glove is more effective at reducing the finger vibration than the air bladder-filled glove. The implications of these findings are discussed. Relevance to industry Prolonged, intensive exposure to hand-transmitted vibration can cause hand-arm vibration syndrome. Vibration-reducing gloves have been used as an alternative approach to reduce the vibration exposure. However, their effectiveness for reducing finger-transmitted vibrations remains unclear. This study enhanced the understanding of the glove effects on finger vibration and provided useful information on the effectiveness of typical VR gloves at reducing the vibration transmitted to the fingers. The new

  11. Analysis of a cylindrical shell vibrating in a cylindrical fluid region

    International Nuclear Information System (INIS)

    Chung, H.; Turula, P.; Mulcahy, T.M.; Jendrzejczyk, J.A.

    1976-08-01

    Analytical and experimental methods are presented for evaluating the vibration characteristics of cylindrical shells such as the thermal liner of the Fast Flux Test Facility (FFTF) reactor vessel. The NASTRAN computer program is used to calculate the natural frequencies, mode shapes, and response to a harmonic loading of a thin, circular cylindrical shell situated inside a fluid-filled rigid circular cylinder. Solutions in a vacuum are verified with an exact solution method and the SAP IV computer code. Comparisons between analysis and experiment are made, and the accuracy and utility of the fluid-solid interaction package of NASTRAN is assessed

  12. Circular polarization memory in single Quantum Dots

    International Nuclear Information System (INIS)

    Khatsevich, S.; Poem, E.; Benny, Y.; Marderfeld, I.; Gershoni, D.; Badolato, A.; Petroff, P. M.

    2010-01-01

    Under quasi-resonant circularly polarized optical excitation, charged quantum dots may emit polarized light. We measured various transitions with either positive, negative or no circular-polarization memory. We explain these observations and quantitatively calculate the polarization spectrum. Our model use the full configuration-interaction method, including the electron-hole exchange interaction, for calculating the quantum dot's confined many-carrier states, along with one assumption regarding the spin relaxation of photoexcited carriers: Electrons maintain their initial spin polarization, while holes do not.

  13. Circularly polarized luminescence of syndiotactic polystyrene

    Science.gov (United States)

    Rizzo, Paola; Abbate, Sergio; Longhi, Giovanna; Guerra, Gaetano

    2017-11-01

    Syndiotactic polystyrene (s-PS) films, when crystallized from the amorphous state by temporary sorption of non-racemic guest molecules (like carvone) not only exhibit unusually high optical activity, both in the UV-Visible and Infrared ranges, but also present circularly polarized luminescence (CPL) with high dissymmetry ratios (g = ΔI/I values in the range 0.02-0.03). Experimental evidences provide support, rather than to the usual molecular circular dichroism, to a supramolecular chiral optical response being extrinsic to the site of photon absorption and emission, possibly associated with a helical morphology of s-PS crystallites.

  14. synthesis, characterization and antibacterial studies of metal

    African Journals Online (AJOL)

    Preferred Customer

    Metal complexes of sulfadiazine with N-alkyl-N-phenyldithiocarbamate. Bull. Chem. Soc. Ethiop. 2013, 27(1). 81 character of the C−N bond, and this is responsible for the shift in the v(C−N) stretching vibrations. In dithiocarbamate complexes, the v(C−S) symmetrical and asymmetrical stretching vibrations are diagnostics of ...

  15. Evaluating the transmitted vibration to operator′s hands hand and effect of protective gloves in real condition, based on International Standard Organization 5349 standard

    Directory of Open Access Journals (Sweden)

    Farhad Forouharmajd

    2016-01-01

    Full Text Available Aims: The objective of this research was an evaluation of hand-held tools vibration acceleration such as circular saw and drill transmitted to operator′s and also to determine the role of glove in vibration reduction of those tools. Materials and Methods: In this study, Bruel and Kjaer Vibration meter with a model of 2231 and its analyzer, 2522, along three types of gloves have been used. Accelerometer transducer installed according to International Standard Organization (ISO 5349:1-2 standards in the case of the operator handles the hand-held tool. In next step, the transducer was placed inside the glove. Results: The results show the most accelerated vibration in axis Y for circular saw while working on Plexiglas. All of the used gloves show a reduction of vibration transmission from tools to hands. Glove of C grouped had a reduction of vibration less than two other groups. Conclusion: Based on ISO 5349-1, 10% of workers who are working with circular saw and drill without using glove will be affiliated to white finger after about 7-12 years. As a whole, the results showed that the anti-vibration gloves should be tested in real conditions before using them.

  16. System for damping vibrations in a turbine

    Science.gov (United States)

    Roberts, III, Herbert Chidsey; Johnson, Curtis Alan; Taxacher, Glenn Curtis

    2015-11-24

    A system for damping vibrations in a turbine includes a first rotating blade having a first ceramic airfoil, a first ceramic platform connected to the first ceramic airfoil, and a first root connected to the first ceramic platform. A second rotating blade adjacent to the first rotating blade includes a second ceramic airfoil, a second ceramic platform connected to the second ceramic airfoil, and a second root connected to the second ceramic platform. A non-metallic platform damper has a first position in simultaneous contact with the first and second ceramic platforms.

  17. Measurement of rabbit eardrum vibration through stroboscopic digital holography

    Energy Technology Data Exchange (ETDEWEB)

    De Greef, Daniël; Dirckx, Joris J. J. [University of Antwerp, Laboratory of BioMedical Physics, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2014-05-27

    In this work, we present a setup for high-power single shot stroboscopic digital holography and demonstrate it in an application on rabbit eardrum vibration measurement. The setup is able to make full-field time-resolved measurements of vibrating surfaces with a precision in the nanometer range in a broad frequency range. The height displacement of the measured object is visualized over the entire surface as a function of time. Vibration magnitude and phase maps can be extracted from these data, the latter proving to be very useful to reveal phase delays across the surface. Such deviations from modal motion indicate energy losses due to internal damping, in contrast to purely elastic mechanics. This is of great interest in middle ear mechanics and finite element modelling. In our setup, short laser pulses are fired at selected instants within the surface vibration period and are recorded by a CCD camera. The timing of the pulses and the exposure of the camera are synchronized to the vibration phase by a microprocessor. The high-power frequency-doubled Nd:YAG laser produces pulses containing up to 5 mJ of energy, which is amply sufficient to record single-shot holograms. As the laser pulse length is 8 ns and the smallest time step of the trigger electronics is 1 μs, vibration measurements of frequencies up to 250 kHz are achievable through this method, provided that the maximum vibration amplitude exceeds a few nanometers. In our application, middle ear mechanics, measuring frequencies extend from 5 Hz to 20 kHz. The experimental setup will be presented, as well as results of measurements on a stretched circular rubber membrane and a rabbit's eardrum. Two of the challenges when measuring biological tissues, such as the eardrum, are low reflectivity and fast dehydration. To increase reflectivity, a coating is applied and to counteract the undesirable effects of tissue dehydration, the measurement setup and software have been optimized for speed without

  18. Laser mass spectrometry with circularly polarized light: circular dichroism of cold molecules in a supersonic gas beam.

    Science.gov (United States)

    Titze, Katharina; Zollitsch, Tilo; Heiz, Ulrich; Boesl, Ulrich

    2014-09-15

    An experiment on chiral molecules that combines circular dichroism (CD) spectroscopy, mass-selective detection by laser mass spectrometry (MS), and cooling of molecules by using a supersonic beam is presented. The combination of the former two techniques (CD-laser-MS) is a new method to investigate chiral molecules and is now used by several research groups. Cooling in a supersonic beam supplies a substantial increase in spectroscopic resolution, a feature that has not yet been used in CD spectroscopy. In the experiments reported herein, a large variation in the electronic CD of carbonyl 3-methylcyclopentanone was observed depending on the excited vibrational modes in the n → π* transition. This finding should be of interest for the detection of chiral molecules and for the theoretical understanding of the CD of vibronic bands. It is expected that this effect will show up in other chiral carbonyls because the n → π* transition is typical for the carbonyl group. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Design and implementation of optical switches based on nonlinear plasmonic ring resonators: Circular, square and octagon

    Science.gov (United States)

    Ghadrdan, Majid; Mansouri-Birjandi, Mohammad Ali

    2018-05-01

    In this paper, all-optical plasmonic switches (AOPS) based on various configurations of circular, square and octagon nonlinear plasmonic ring resonators (NPRR) were proposed and numerically investigated. Each of these configurations consisted of two metal-insulator-metal (MIM) waveguides coupled to each other by a ring resonator (RR). Nonlinear Kerr effect was used to show switching performance of the proposed NPRR. The result showed that the octagon switch structure had lower threshold power and higher transmission ratio than square and circular switch structures. The octagon switch structure had a low threshold power equal to 7.77 MW/cm2 and the high transmission ratio of approximately 0.6. Therefore, the octagon switch structure was an appropriate candidate to be applied in optical integration circuits as an AOPS.

  20. Circular arc snakes and kinematic surface generation

    KAUST Repository

    Barton, Michael; Shi, Ling; Kilian, Martin; Wallner, Johannes; Pottmann, Helmut

    2013-01-01

    of circular arcs is well suited for such purposes, and allows us to reduce evolution of curves to the evolution of a control point collection in a certain finite-dimensional shape space. We approach this evolution by a 2-step process: linearized evolution via

  1. Symmetric Circular Matchings and RNA Folding

    DEFF Research Database (Denmark)

    Hofacker, Ivo L.; Reidys, Christian; Stadler, Peter F.

    2012-01-01

    RNA secondary structures can be computed as optimal solutions of certain circular matching problems. An accurate treatment of this energy minimization problem has to account for the small --- but non-negligible --- entropic destabilization of secondary structures with non-trivial automorphisms. S...

  2. Solid angle subtended by two circular discs

    International Nuclear Information System (INIS)

    Gilly, Louis.

    1978-09-01

    Methods of calculation of solid angles, subtended by two circular discs are analysed. Calculus are methodically classified as follow: series development Legendre polynomes, defined integral, elliptic integrals, Bessel integrals, multiple integrals, Monte Carlo method, electrostatic analogy. Applications in Nuclear Physics are added as examples. List of numeric tables completes bibliography [fr

  3. Stability analysis of cylinders with circular cutouts

    Science.gov (United States)

    Almroth, B. O.; Brogan, F. A.; Marlowe, M. B.

    1973-01-01

    The stability of axially compressed cylinders with circular cutouts is analyzed numerically. An extension of the finite-difference method is used which removes the requirement that displacement components be defined in the directions of the grid lines. The results of this nonlinear analysis are found to be in good agreement with earlier experimental results.

  4. Institutional incentives in circular economy transition

    NARCIS (Netherlands)

    Fischer, Aglaia; Pascucci, Stefano

    2017-01-01

    The aim of this paper is to gain insight into how requirements for transitioning to circular economy creates new organizational forms in inter-firm collaborations, and ultimately how they stimulate the emergence of new institutions enhancing sustainability. Two strands of literature, one on

  5. Beam Dynamics and Beam Losses - Circular Machines

    CERN Document Server

    Kain, V

    2016-01-01

    A basic introduction to transverse and longitudinal beam dynamics as well as the most relevant beam loss mechanisms in circular machines will be presented in this lecture. This lecture is intended for physicists and engineers with little or no knowledge of this subject.

  6. Shear stresses around circular cylindrical openings

    NARCIS (Netherlands)

    Hoogenboom, P.C.J.; Van Weelden, C.; Blom, C.M.B.

    2010-01-01

    In this paper stress concentrations are studied around circular cylindrical openings or voids in a linear elastic continuum. The loading is such that a uniform shear stress occurs in the continuum, which is disturbed by the opening. The shear stress is in the direction of the centre axis of the

  7. Magnetohydrodynamic flow past a circular cylinder

    International Nuclear Information System (INIS)

    Swarup, S.; Sinha, P.C.

    1977-01-01

    This paper deals with the slow-flow problem of an incompressible, viscous, electrically conducting fluid past a circular cylinder in an alignment magnetic field. The solutions for the velocity and magnetic fields as sought by the method of matched asymptotic expansions under the assumptions R,Rsub(m) 2 ) and O(R/log M), respectively. (Auth.)

  8. Photoexcitation circular dichroism in chiral molecules

    Science.gov (United States)

    Beaulieu, S.; Comby, A.; Descamps, D.; Fabre, B.; Garcia, G. A.; Géneaux, R.; Harvey, A. G.; Légaré, F.; Mašín, Z.; Nahon, L.; Ordonez, A. F.; Petit, S.; Pons, B.; Mairesse, Y.; Smirnova, O.; Blanchet, V.

    2018-05-01

    Chiral effects appear in a wide variety of natural phenomena and are of fundamental importance in science, from particle physics to metamaterials. The standard technique of chiral discrimination—photoabsorption circular dichroism—relies on the magnetic properties of a chiral medium and yields an extremely weak chiral response. Here, we propose and demonstrate an orders of magnitude more sensitive type of circular dichroism in neutral molecules: photoexcitation circular dichroism. This technique does not rely on weak magnetic effects, but takes advantage of the coherent helical motion of bound electrons excited by ultrashort circularly polarized light. It results in an ultrafast chiral response and the efficient excitation of a macroscopic chiral density in an initially isotropic ensemble of randomly oriented chiral molecules. We probe this excitation using linearly polarized laser pulses, without the aid of further chiral interactions. Our time-resolved study of vibronic chiral dynamics opens a way to the efficient initiation, control and monitoring of chiral chemical change in neutral molecules at the level of electrons.

  9. Time can't be circular

    CERN Multimedia

    2003-01-01

    "Delivering the Albert Einstein lecture at the Centre for Philosophy and Foundations of Science on Tuesday, Nobel Laureate Professor Gerard Hooft said that any notion of time can not be circular or have loops or multi dimensionality" (1/2 page).

  10. 76 FR 60590 - Environmental Justice; Proposed Circular

    Science.gov (United States)

    2011-09-29

    ... oral presentations about the two proposed Circulars and allow attendees an opportunity to ask... of the comfort and safety of all attendees and the maximum seating capacity of meeting rooms, FTA... and non-traditional media, as well as digital media. Additional strategies to increase involvement of...

  11. 78 FR 14620 - Joint Development: Proposed Circular

    Science.gov (United States)

    2013-03-06

    ... development. This circular provides guidance to recipients of Federal Transit Administration (FTA) financial... of opportunities for private sector participation in public transportation projects, and includes the... ``value capture'' mechanisms, such as income derived from rental or lease payments, and private sector...

  12. Circular symmetry in topologically massive gravity

    International Nuclear Information System (INIS)

    Deser, S; Franklin, J

    2010-01-01

    We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null. (note)

  13. NOTE: Circular symmetry in topologically massive gravity

    Science.gov (United States)

    Deser, S.; Franklin, J.

    2010-05-01

    We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null.

  14. Circular symmetry in topologically massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Deser, S [Physics Department, Brandeis University, Waltham, MA 02454 (United States); Franklin, J, E-mail: deser@brandeis.ed, E-mail: jfrankli@reed.ed [Reed College, Portland, OR 97202 (United States)

    2010-05-21

    We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null. (note)

  15. Periodic Solutions for Circular Restricted -Body Problems

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Zhao

    2013-01-01

    Full Text Available For circular restricted -body problems, we study the motion of a sufficiently small mass point (called the zero mass point in the plane of equal masses located at the vertices of a regular polygon. By using variational minimizing methods, for some , we prove the existence of the noncollision periodic solution for the zero mass point with some fixed wingding number.

  16. Administrative Circular n° 12

    CERN Document Server

    2005-01-01

    Following a recommendation by the Standing Concertation Committee, the Director-General has approved the amounts used for the reimbursements mentioned in Administrative Circular N° 12 as follows : The figures, effective from 1 September 2005, are : § 8a : 16.50 Swiss francs § 9a : 662 Swiss francs § 9b : 33 Swiss francs

  17. the mathematics of ghanaian circular musical drumheads

    African Journals Online (AJOL)

    User

    overtones. INTRODUCTION. The mathematics of percussion drums and other musical instruments has been delved into by lots of researchers tackling it from different angles, and especially for circular drumheads with constant tension. Such drums include the conga which usually produces rhythmic sounds. But little or no ...

  18. Home Sewage Disposal. Special Circular 212.

    Science.gov (United States)

    Wooding, N. Henry

    This circular provides current information for homeowners who must repair or replace existing on-lot sewage disposal systems. Site requirements, characteristics and preparation are outlined for a variety of alternatives such as elevated sand mounds, sand-lined beds and trenches, and oversized absorption area. Diagrams indicating construction…

  19. Breaking the Barriers to the Circular Economy

    NARCIS (Netherlands)

    Kirchherr, J.W.; Hekkert, M.P.; Bour, Ruben; Huijbrechtse-Truijens, Anne; Kostense-Smit, Erica; Muller, Jennifer

    2017-01-01

    The Copernicus Institute of Sustainable Development, Utrecht University, the Netherlands and Deloitte have jointly carried out research on barriers to the Circular Economy (CE) in the European Union. For this research, a survey with 153 businesses, 55 government officials and expert interviews with

  20. Falling aprons at circular piers under currents

    NARCIS (Netherlands)

    De Sonneville, B.; Van Velzen, G.; Verheij, H.J.; Dorst, K.

    2012-01-01

    Traditional guidelines on rock protection at circular piers predominantly focus on preventing shear failure (by choosing a sufficiently large rock size), winnowing failure (by designing an appropriate filter) and edge failure (by selecting a sufficient extent). In particular areas (e.g. in an

  1. Pickin’ up good vibrations

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    In preparation for the civil engineering work on the HL-LHC, vibration measurements were carried out at the LHC’s Point 1 last month. These measurements will help evaluate how civil engineering work could impact the beam, and will provide crucial details about the site’s geological make-up before construction begins.   A seismic truck at Point 1 generated wave-like vibrations measured by EN/MME. From carrying out R&D to produce state-of-the-art magnets to developing innovative, robust materials capable of withstanding beam impact, the HL-LHC is a multi-faceted project involving many groups and teams across CERN’s departments. It was in this framework that the project management mandated CERN's Mechanical and Materials Engineering (EN/MME) group to measure the propagation of vibrations around Point 1. Their question: can civil engineering work for the HL-LHC – the bulk of which is scheduled for LS2 – begin while the LHC is running? Alth...

  2. Vibrational stability of graphene

    Directory of Open Access Journals (Sweden)

    Yangfan Hu

    2013-05-01

    Full Text Available The mechanical stability of graphene as temperature rises is analyzed based on three different self-consistent phonon (SCP models. Compared with three-dimensional (3-D materials, the critical temperature Ti at which instability occurs for graphene is much closer to its melting temperature Tm obtained from Monte Carlo simulation (Ti ≃ 2Tm, K. V. Zakharchenko, A. Fasolino, J. H. Los, and M. I. Katsnelson, J. Phys. Condens. Matter 23, 202202. This suggests that thermal vibration plays a significant role in melting of graphene while melting for 3-D materials is often dominated by topologic defects. This peculiar property of graphene derives from its high structural anisotropy, which is characterized by the vibrational anisotropic coefficient (VAC, defined upon its Lindermann ratios in different directions. For any carbon based material with a graphene-like structure, the VAC value must be smaller than 5.4 to maintain its stability. It is also found that the high VAC value of graphene is responsible for its negative thermal expansion coefficient at low temperature range. We believe that the VAC can be regarded as a new criterion concerning the vibrational stability of any low-dimensional (low-D materials.

  3. Plasmon mediated non-photochemical nucleation of nanoparticles by circularly polarized light

    OpenAIRE

    Karpov, Victor G.; Grigorchuk, Nicholas I.

    2014-01-01

    We predict nucleation of pancake shaped metallic nanoparticles having plasmonic frequencies in resonance with a non-absorbed circularly polarized electromagnetic field. We show that the same field can induce nucleation of randomly oriented needle shaped particles. The probabilities of these shapes are estimated vs. field frequency and strength, material parameters, and temperature. This constitutes a quantitative model of non-photochemical laser induced nucleation (NPLIN) consistent with the ...

  4. Circular Dichroism is Sensitive to Monovalent Cation Binding in Monensin Complexes

    Czech Academy of Sciences Publication Activity Database

    Nedzhib, A.; Kessler, Jiří; Bouř, Petr; Gyurcsik, B.; Pantcheva, I.

    2016-01-01

    Roč. 28, č. 5 (2016), s. 420-428 ISSN 0899-0042 R&D Projects: GA ČR GA15-09072S; GA ČR(CZ) GA16-05935S Institutional support: RVO:61388963 Keywords : monovalent polyether ionophore * metal complexes * synchrotron radiation circular dichroism * time-dependent density functional theory Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.956, year: 2016

  5. Silicon Micromachined Sensor for Broadband Vibration Analysis

    Science.gov (United States)

    Gutierrez, Adolfo; Edmans, Daniel; Cormeau, Chris; Seidler, Gernot; Deangelis, Dave; Maby, Edward

    1995-01-01

    The development of a family of silicon based integrated vibration sensors capable of sensing mechanical resonances over a broad range of frequencies with minimal signal processing requirements is presented. Two basic general embodiments of the concept were designed and fabricated. The first design was structured around an array of cantilever beams and fabricated using the ARPA sponsored multi-user MEMS processing system (MUMPS) process at the Microelectronics Center of North Carolina (MCNC). As part of the design process for this first sensor, a comprehensive finite elements analysis of the resonant modes and stress distribution was performed using PATRAN. The dependence of strain distribution and resonant frequency response as a function of Young's modulus in the Poly-Si structural material was studied. Analytical models were also studied. In-house experimental characterization using optical interferometry techniques were performed under controlled low pressure conditions. A second design, intended to operate in a non-resonant mode and capable of broadband frequency response, was proposed and developed around the concept of a cantilever beam integrated with a feedback control loop to produce a null mode vibration sensor. A proprietary process was used to integrat a metal-oxide semiconductor (MOS) sensing device, with actuators and a cantilever beam, as part of a compatible process. Both devices, once incorporated as part of multifunction data acquisition and telemetry systems will constitute a useful system for NASA launch vibration monitoring operations. Satellite and other space structures can benefit from the sensor for mechanical condition monitoring functions.

  6. A novel vibration assisted polishing device based on the flexural mechanism driven by the piezoelectric actuators

    Directory of Open Access Journals (Sweden)

    Guilian Wang

    2018-01-01

    Full Text Available The vibration assisted polishing has widely application fields because of higher machining frequency and better polishing quality, especially the polishing with the non-resonant mode that is regarded as a kind of promising polishing method. This paper reports a novel vibration assisted polishing device, consisting of the flexible hinge mechanism driven by the piezoelectric actuators, which is suitable for polishing planes or curve surfaces with slow curvature. Firstly, the generation methods of vibration trajectory are investigated for the same frequency and different frequency signals’ inputs, respectively, and then the types of elliptic and Lissajous’s vibration trajectories are generated respectively. Secondly, a flexural mechanism consisting of the right circular flexible hinges and the leaf springs is developed to produce two-dimensional vibration trajectory. Statics and dynamics investigating of this flexible mechanism are finished in detail. The analytical models about input and output compliances of the flexural mechanism are established according to the matrix-based compliance modeling, and the dynamic model of the flexural mechanism based on the Euler-Lagrange equation is also presented. The finite element model of the flexural mechanism was established to carry out the numerical simulation in order to testify the rationality of device design. Finally, the polishing experiment is carried out to prove the effectiveness of the vibration device. The experimental results show that this novel vibration assisted polishing device developed in this study can remove more effectively the cutting marks left by last process and obviously reduce the workpiece surface roughness.

  7. PIV measurement of the complex and transient cross-flow over a circular cylinder

    International Nuclear Information System (INIS)

    Kuwabara, Joji; Someya, Satoshi; Okamoto, Koji

    2007-01-01

    This paper describe about measurement for the complex and transient cross-flow over a circular cylinder with the dynamic (time resolved) PIV (particle image velocimetry) techniques. The experiment was carried out water flow tunnel with a working section of 50x50 mm, at the Reynolds number 6.7 x 10 3 to 2.7 x 10 4 . This circular cylinder constructed with MEXFLON resin, the end of circular cylinder is rigidly supported and the other is free. The MEXFLON is fluorine resin; its refractive index is almost same as the water with high transparency. Very high speed water flow among the test section had been clearly visualized and captured by high speed camera. The fluctuations of the flow structure also are clearly obtained with high spatial and high temporal resolution, 512x512pixel with 10,000fps. It corresponds to set up number of thousands LDV array at the test section. Consequently, we found there are asynchronous vibration between parallel-ward and perpendicular-ward to main flow. (author)

  8. Solid Angle Computations for a Circular Radiator and a Circular Detector

    Energy Technology Data Exchange (ETDEWEB)

    Konijn, J; Tollander, B

    1963-02-15

    The problem of particle detection, when using an isotropic neutron point source at different distances from a circular target or a radioactive source as seen by a circular detector, e. g. a solid state counter, is dealt with. Tables are given for different distances of the source when the reaction at the target has an isotropic or a cosine angular distribution in the laboratory system.

  9. Insight into vibrational circular dichroism of proteins by density functional modeling

    Czech Academy of Sciences Publication Activity Database

    Kessler, Jiří; Andrushchenko, Valery; Kapitán, J.; Bouř, Petr

    2018-01-01

    Roč. 20, č. 7 (2018), s. 4926-4935 ISSN 1463-9076 R&D Projects: GA MŠk(CZ) LTC17012; GA ČR(CZ) GA16-05935S; GA ČR(CZ) GA16-04902S Institutional support: RVO:61388963 Keywords : Raman optical activity * molecular property tensors * coupled oscillator model Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

  10. Advisory Circular checklist and status of other FAA publications

    Science.gov (United States)

    1997-08-15

    This 1997 circular transmits the revised checklist of the Federal Aviation : Administration's (FAA) Advisory Circulars (AC's). It also lists certain other : FAA publications sold by the Superintendent of Documents.

  11. Random vibrations theory and practice

    CERN Document Server

    Wirsching, Paul H; Ortiz, Keith

    1995-01-01

    Random Vibrations: Theory and Practice covers the theory and analysis of mechanical and structural systems undergoing random oscillations due to any number of phenomena— from engine noise, turbulent flow, and acoustic noise to wind, ocean waves, earthquakes, and rough pavement. For systems operating in such environments, a random vibration analysis is essential to the safety and reliability of the system. By far the most comprehensive text available on random vibrations, Random Vibrations: Theory and Practice is designed for readers who are new to the subject as well as those who are familiar with the fundamentals and wish to study a particular topic or use the text as an authoritative reference. It is divided into three major sections: fundamental background, random vibration development and applications to design, and random signal analysis. Introductory chapters cover topics in probability, statistics, and random processes that prepare the reader for the development of the theory of random vibrations a...

  12. VIBRATION ISOLATION SYSTEM PROBABILITY ANALYSIS

    Directory of Open Access Journals (Sweden)

    Smirnov Vladimir Alexandrovich

    2012-10-01

    Full Text Available The article deals with the probability analysis for a vibration isolation system of high-precision equipment, which is extremely sensitive to low-frequency oscillations even of submicron amplitude. The external sources of low-frequency vibrations may include the natural city background or internal low-frequency sources inside buildings (pedestrian activity, HVAC. Taking Gauss distribution into account, the author estimates the probability of the relative displacement of the isolated mass being still lower than the vibration criteria. This problem is being solved in the three dimensional space, evolved by the system parameters, including damping and natural frequency. According to this probability distribution, the chance of exceeding the vibration criteria for a vibration isolation system is evaluated. Optimal system parameters - damping and natural frequency - are being developed, thus the possibility of exceeding vibration criteria VC-E and VC-D is assumed to be less than 0.04.

  13. Enhanced Circular Dichroism of Gold Bilayered Slit Arrays Embedded with Rectangular Holes.

    Science.gov (United States)

    Zhang, Hao; Wang, Yongkai; Luo, Lina; Wang, Haiqing; Zhang, Zhongyue

    2017-01-01

    Gold bilayered slit arrays with rectangular holes embedded into the metal surface are designed to enhance the circular dichroism (CD) effect of gold bilayered slit arrays. The rectangular holes in these arrays block electric currents and generate localized surface plasmons around these holes, thereby strengthening the CD effect. The CD enhancement factor depends strongly on the rotational angle and the structural parameters of the rectangular holes; this factor can be enhanced further by drilling two additional rectangular holes into the metal surfaces of the arrays. These results help facilitate the design of chiral structures to produce a strong CD effect and large electric fields.

  14. Vibration damping method and apparatus

    Science.gov (United States)

    Redmond, James M.; Barney, Patrick S.; Parker, Gordon G.; Smith, David A.

    1999-01-01

    The present invention provides vibration damping method and apparatus that can damp vibration in more than one direction without requiring disassembly, that can accommodate varying tool dimensions without requiring re-tuning, and that does not interfere with tool tip operations and cooling. The present invention provides active dampening by generating bending moments internal to a structure such as a boring bar to dampen vibration thereof.

  15. Absolute Configuration of a Cyclic Dipeptide Reflected in Vibrational Optical Activity: Ab Initio and Experimental Investigation

    Czech Academy of Sciences Publication Activity Database

    Li, X.; Hopmann, K. H.; Hudecová, Jana; Stensen, W.; Novotná, J.; Urbanová, M.; Svendsen, J. S.; Bouř, Petr; Ruud, K.

    2012-01-01

    Roč. 116, č. 10 (2012), s. 2554-2563 ISSN 1089-5639 R&D Projects: GA ČR GAP208/11/0105; GA MŠk(CZ) LH11033 Grant - others:AV ČR(CZ) M200550902 Institutional research plan: CEZ:AV0Z40550506 Keywords : cyclic dipeptide * vibrational otpical activity * density functional theory * dispersion * electronic circular dichroism Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.771, year: 2012

  16. In-plane vibrations of inhomogeneous curved bars having varying cross-section

    International Nuclear Information System (INIS)

    Suzuki, Katsuyoshi; Kosawada, Tadashi; Takahashi, Shin

    1986-01-01

    An exact method using power series expansions is presented for solving in-plane free vibration problems of inhomogeneous curved bars having varying curvatures and cross-sections. Equations of motion and boundary conditions are derived from the stationary conditions of the Lagrangian of curved bars. Natural frequencies and mode shapes are presented for elliptical and circular arc bars having both ends clamped and calmped-free ends. (author)

  17. Out-of-plane vibrations of inhomogeneous curved bars having varying cross-sections

    International Nuclear Information System (INIS)

    Suzuki, Katsuyoshi; Kosawada, Tadashi

    1987-01-01

    An exact method using power series expansions is presented for solving out-of-plane free vibrations of inhomogeneous curved bars with varying curvatures and cross-sections. Equations of motion and boundary conditions are derived from the stationary conditions of the Lagrangian of curved bars. Natural frequencies and mode shapes are presented for elliptical and circular arc bars having both ends clamped and clamped-free ends. (author)

  18. Determining the Absolute Configuration of Two Marine Compounds Using Vibrational Chiroptical Spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Hopmann, K. H.; Šebestík, Jaroslav; Novotná, J.; Stensen, W.; Urbanová, M.; Svenson, J.; Svendsen, J. S.; Bouř, Petr; Ruud, K.

    2012-01-01

    Roč. 77, č. 2 (2012), s. 858-869 ISSN 0022-3263 R&D Projects: GA ČR GAP208/11/0105; GA MŠk(CZ) LH11033 Institutional research plan: CEZ:AV0Z40550506 Keywords : vibrational circular dichroism * Raman optical activity * absolute configuration * bioprospecting Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.564, year: 2012

  19. Development pattern of circular economy in Jiangsu coastland

    OpenAIRE

    Wang, Liang

    2009-01-01

    Circular economy is an effective development pattern to balance economic growth, social development and environmental protection. Based on apprehending the connotation of circular economy, this paper fully considers and studies on the future trends in this area according to the theory of circular economy and the empirical circumstances of Jiangsu Coastland. This paper also discusses the circular economy development pattern adopted by Jiangsu coastland during economic and social development fr...

  20. Numerical Calculation and Experiment of Coupled Dynamics of the Differential Velocity Vane Pump Driven by the Hybrid Higher-order Fourier Non-circular Gears

    Science.gov (United States)

    Xu, Gaohuan; Chen, Jianneng; Zhao, Huacheng

    2018-06-01

    The transmission systems of the differential velocity vane pumps (DVVP) have periodic vibrations under loads. And it is not easy to find the reason. In order to optimize the performance of the pump, the authors proposed DVVP driven by the hybrid Higher-order Fourier non-circular gears and tested it. There were also similar periodic vibrations and noises under loads. Taking into account this phenomenon, the paper proposes fluid mechanics and solid mechanics simulation methodology to analyze the coupling dynamics between fluid and transmission system and reveals the reason. The results show that the pump has the reverse drive phenomenon, which is that the blades drive the non-circular gears when the suction and discharge is alternating. The reverse drive phenomenon leads the sign of the shaft torque to be changed in positive and negative way. So the transmission system produces torsional vibrations. In order to confirm the simulation results, micro strains of the input shaft of the pump impeller are measured by the Wheatstone bridge and wireless sensor technology. The relationships between strain and torque are obtained by experimental calibration, and then the true torque of input shaft is calculated indirectly. The experimental results are consistent to the simulation results. It is proven that the periodic vibrations are mainly caused by fluid solid coupling, which leads to periodic torsional vibration of the transmission system.

  1. Vibrations used to talk to quantum circuits

    Science.gov (United States)

    Cho, Adrian

    2018-03-01

    The budding discipline of quantum acoustics could shake up embryonic quantum computers. Such machines run by flipping quantum bits, or qubits, that can be set not only to zero or one, but, bizarrely, to zero and one at the same time. The most advanced qubits are circuits made of superconducting metal, and to control or read out a qubit, researchers make it interact with a microwave resonator—typically a strip of metal on the qubit chip or a finger-size cavity surrounding it—which rings with microwave photons like an organ pipe rings with sound. But some physicists see advantages to replacing the microwave resonator with a mechanical one that rings with quantized vibrations, or phonons. A well-designed acoustic resonator could ring longer than a microwave one does and could be far smaller, enabling researchers to produce more compact technologies. But first scientists must gain quantum control over vibrations. And several groups are on the cusp of doing that, as they reported at a recent meeting.

  2. In-situ cyclic stress experiment at the Clinton P. Anderson Meson Physics Facility (LAMPF) for determining the effect of dislocation vibration on void growth in metals during irradiation

    International Nuclear Information System (INIS)

    Green, W.V.; Sommer, W.F.; Coulter, C.A.

    1979-01-01

    Experience is reported with the first in-situ cyclic-stress irradiation at LAMPF. A proton beam ion current of 3 to 6 μA of 800 MeV protons was utilized for 24 days irradiation. Radiation damage effects of 800 MeV protons incident on a 1-cm thick Cu target were calculated using the nucleon-meson transport code to determine the nuclear reactions produced by the protons, the theory of Lindhard to evaluate the resultant damage energy deposited in the target. These calculations have been extended to Al. Damage effects were nearly uniform through a 1-cm target thickness, and the results obtained can be expressed in cross section form. The calculation yielded a damage energy cross section of about 63 barn-keV, a nuclear transmutation cross section of 0.44 barns, and indicated copious hydrogen, helium, and neutron production. Analysis of the effect of dislocation vibration on the efficiency of a dislocation line as a sink for point defects predicted that dislocation vibration should suppress void growth. The effect results from the fact that the dislocation will sweep up vacancies, which diffuse less rapidly than interstitials. The growth rate of voids in Al under simultaneous proton irradiation and cyclic stressing are compared to that of samples irradiated at the same time but without any stressing. The samples are placed one behind the other along the proton path so that identical irradiation histories can be achieved. The temperature of the samples is controlled, known and uniform. The initial preirradiation state is a prestrained state of a few hundred stress cycles. The samples are irradiated without stress through the incubation period for void nucleation before the cyclic stress is applied

  3. A product design framework for a circular economy

    NARCIS (Netherlands)

    Van den Berg, M.R.; Bakker, C.A.

    2015-01-01

    The paper provides a circular economy framework from a product design perspective with tools to aid product designers in applying circular product design in practice. Design research for circular economy has so far mainly been limited to referring to existing fields of research such as design for

  4. 12 CFR 563g.8 - Use of the offering circular.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Use of the offering circular. 563g.8 Section 563g.8 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY SECURITIES OFFERINGS § 563g.8 Use of the offering circular. (a) An offering circular or amendment declared effective by the...

  5. Photoinduced Circular Anisotropy in Side-Chain Azobenzene Polyesters

    DEFF Research Database (Denmark)

    Nikolova, L.; Todorov, T.; Ivanov, M.

    1997-01-01

    We report for the first time the inducing of large circular anisotropy in previously unoriented films of side-chain azobenzene polyesters on illumination with circularly polarized light at a wavelength of 488 nm. The circular dichroism and optical activity are measured simultaneously in real time...

  6. The Circular Economy: In Practice-focused Undergraduate Engineering Education

    DEFF Research Database (Denmark)

    Knudby, Torben; Larsen, Samuel

    2017-01-01

    The growth of the planet’s population makes the traditional industrial model of “take, make and waste” unsustainable. The circular economy, in which resources are continuously reused, offers a solution. For manufacturers of durable goods the circular economy requires a well-functioning circular...

  7. Looking Down Under for a Circular Economy of Indium.

    Science.gov (United States)

    Werner, Tim T; Ciacci, Luca; Mudd, Gavin Mark; Reck, Barbara K; Northey, Stephen Alan

    2018-02-20

    Indium is a specialty metal crucial for modern technology, yet it is potentially critical due to its byproduct status in mining. Measures to reduce its criticality typically focus on improving its recycling efficiency at end-of-life. This study quantifies primary and secondary indium resources ("stocks") for Australia through a dynamic material-flow analysis. It is based on detailed assessments of indium mineral resources hosted in lead-zinc and copper deposits, respective mining activities from 1844 to 2013, and the trade of indium-containing products from 1988 to 2015. The results show that Australia's indium stocks are substantial, estimated at 46.2 kt in mineral resources and an additional 14.7 kt in mine wastes. Australian mineral resources alone could meet global demand (∼0.8 kt/year) for more than five decades. Discarded material from post-consumer products, instead, is negligible (43 t). This suggests that the resilience of Australia's indium supply can best be increased through efficiency gains in mining (such as introducing domestic indium refining capacity) rather than at the end of the product life. These findings likely also apply to other specialty metals, such as gallium or germanium, and other resource-dominated countries. Finally, the results illustrate that national circular economy strategies can differ substantially.

  8. Dual circularly polarized broadside beam antenna based on metasurfaces

    Science.gov (United States)

    Tellechea, A.; Caminita, F.; Martini, E.; Ederra, I.; Teniente, J.; Iriarte, J. C.; Gonzalo, R.; Maci, S.

    2018-02-01

    Design details of a Ku band metasurface (MTS) antenna with dual circularly polarized (CP) broadside radiation is shown in this work. By means of the surface impedance tensor modulation, synchronized propagation of two transversal magnetic (TM) and transverse electric (TE) surface waves (SWs) is ensured in the structure, which contribute to the radiation in broadside direction by the generation of a CP leaky wave. The structure is implemented by elliptical subwavelength metallic elements with a cross-shaped aperture in the center, printed on top of a thin substrate with high permittivity (AD1000 with a thickness of λ0/17). For the experimental validation, the MTS prototype has been excited employing an orthomode transducer composed by a metallic stepped septum inside an air-filled waveguide. Two orthogonal TE11 modes excited with ±90° phase shift in the feed couple with the TM and TE SWs supported by the MTS and generate RHCP or LHCP broadside beam. Experimental results are compared with the simulation predictions. Finally, conclusions are drawn.

  9. Vibrational analysis of various irotopes of L-alanyl-L-alanine in aqueous solution: Vibrational Absorption (VA), Vibrational Circular Dichroism (VCD), Raman and Raman Optical Activity (ROA) Spectra

    DEFF Research Database (Denmark)

    Jalkanen, Karl J.; Nieminen, R.M.; Knapp-Mohammady, M.

    2003-01-01

    . DFT Becke3LYP/6-31G* theory has been used to determine the geometry, Hessian, atomic polar tensors (APT), and atomic axial tensors (AAT), and the electric dipole-electric dipole polarizability derivatives (EDEDPD), which are required for us to simulate the VA, VCD, and Raman spectra. The electric...

  10. Digital analysis of vibrations

    International Nuclear Information System (INIS)

    Bohnstedt, H.J.; Walter, G.

    1982-01-01

    Vibrational measurements, e.g. on turbomachinery, can be evaluated rapidly and economically with the aid of a combination of the following instruments: a desk-top computer, a two-channel vector filter and a FFT spectral analyzer. This equipment combination is available within the Allianz Centre for Technology and has also been used for mobile, on-site investigations during the last year. It enables calculation and display of time functions, kinetic shaft orbits, displacement diagrams. Bode plots, polar-coordinate plots, cascade diagrams and histograms. (orig.) [de

  11. Turbine blade vibration dampening

    Science.gov (United States)

    Cornelius, C.C.; Pytanowski, G.P.; Vendituoli, J.S.

    1997-07-08

    The present turbine wheel assembly increases component life and turbine engine longevity. The combination of the strap and the opening combined with the preestablished area of the outer surface of the opening and the preestablished area of the outer circumferential surface of the strap and the friction between the strap and the opening increases the life and longevity of the turbine wheel assembly. Furthermore, the mass ``M`` or combined mass ``CM`` of the strap or straps and the centrifugal force assist in controlling vibrations and damping characteristics. 5 figs.

  12. Lattice Vibrations in Chlorobenzenes:

    DEFF Research Database (Denmark)

    Reynolds, P. A.; Kjems, Jørgen; White, J. W.

    1974-01-01

    Lattice vibrational dispersion curves for the ``intermolecular'' modes in the triclinic, one molecule per unit cell β phase of p‐C6D4Cl2 and p‐C6H4Cl2 have been obtained by inelastic neutron scattering. The deuterated sample was investigated at 295 and at 90°K and a linear extrapolation to 0°K...... was applied in order to correct for anharmonic effects. Calculations based on the atom‐atom model for van der Waals' interaction and on general potential parameters for the aromatic compounds agree reasonably well with the experimental observations. There is no substantial improvement in fit obtained either...

  13. Vibration control, machine diagnostics

    International Nuclear Information System (INIS)

    1990-01-01

    Changing vibrations announce damage in the form of wear or cracks on components of, e.g., engine rotors, pumps, power plant turbo sets, rounding-up tools, or marine diesel engines. Therefore, machine diagnostics use frequency analyses, system tests, trend analyses as well as expert systems to localize or estimate the causes of these damages and malfunctions. Data acquisistion, including not only sensors, but also reliable and redundant data processing systems and analyzing systems, play an important role. The lectures pertaining to the data base are covered in detail. (DG) [de

  14. Simulation of car movement along circular path

    Science.gov (United States)

    Fedotov, A. I.; Tikhov-Tinnikov, D. A.; Ovchinnikova, N. I.; Lysenko, A. V.

    2017-10-01

    Under operating conditions, suspension system performance changes which negatively affects vehicle stability and handling. The paper aims to simulate the impact of changes in suspension system performance on vehicle stability and handling. Methods. The paper describes monitoring of suspension system performance, testing of vehicle stability and handling, analyzes methods of suspension system performance monitoring under operating conditions. The mathematical model of a car movement along a circular path was developed. Mathematical tools describing a circular movement of a vehicle along a horizontal road were developed. Turning car movements were simulated. Calculation and experiment results were compared. Simulation proves the applicability of a mathematical model for assessment of the impact of suspension system performance on vehicle stability and handling.

  15. Behaviour of a stiffened circular slab

    International Nuclear Information System (INIS)

    Kulkarni, M.G.; Subramanian, K.V.

    1975-01-01

    Configuration of intake structure for cooling water system for Madras Atomic Power Project was studied on a hydraulic model and it was recommended to provide a circular slab in the structure to give directional property to the inflow and reduce air entrainment. This slab, as indicated by hydraulic model tests was required to withstand hydrodynamic pressures of the order of 10T/m 2 due to breaking waves of about 6 m height. Analysis of this circular cover slab, Stiffened by radial and circumferential beams, carried with the help of an analysis based on grid idealisation is presented. Results of approximate design analysis to assess behaviour of radial stiffener have been compared. Actual design is based on judgement of actual degree of fixity possessed by the supports or restraints. (author)

  16. Design of circular differential microphone arrays

    CERN Document Server

    Benesty, Jacob; Cohen, Israel

    2015-01-01

    Recently, we proposed a completely novel and efficient way to design differential beamforming algorithms for linear microphone arrays. Thanks to this very flexible approach, any order of differential arrays can be designed. Moreover, they can be made robust against white noise amplification, which is the main inconvenience in these types of arrays. The other well-known problem with linear arrays is that electronic steering is not really feasible.  In this book, we extend all these fundamental ideas to circular microphone arrays and show that we can design small and compact differential arrays of any order that can be electronically steered in many different directions and offer a good degree of control of the white noise amplification problem, high directional gain, and frequency-independent response. We also present a number of practical examples, demonstrating that differential beamforming with circular microphone arrays is likely one of the best candidates for applications involving speech enhancement (i....

  17. Injection and extraction techniques in circular accelerators

    International Nuclear Information System (INIS)

    Tang Jingyu

    2008-01-01

    Injection and extraction are usually the key systems in circular accelerators. They play important roles in transferring the beam from one stage acceleration to the other or to experimental stations. It is also in the injection and extraction regions where beam losses happen mostly. Due to the tight space and to reduce the perturbation to the circulating orbit, the devices are usually designed to meet special requirements such as compactness, small stray field, fast rise time or fall time, etc. Usual injection and extraction devices include septum magnets, kicker magnets, electrostatic deflectors, slow bump magnets and strippers. In spite of different accelerators and specification for the injection and extraction devices, many techniques are shared in the design and manufacturing. This paper gives a general review on the techniques employed in the major circular accelerators in China. (authors)

  18. Customized DSP-based vibration measurement for wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    LaWhite, N.E.; Cohn, K.E. [Second Wind Inc., Somerville, MA (United States)

    1996-12-31

    As part of its Advanced Distributed Monitoring System (ADMS) project funded by NREL, Second Wind Inc. is developing a new vibration measurement system for use with wind turbines. The system uses low-cost accelerometers originally designed for automobile airbag crash-detection coupled with new software executed on a Digital Signal Processor (DSP) device. The system is envisioned as a means to monitor the mechanical {open_quotes}health{close_quotes} of the wind turbine over its lifetime. In addition the system holds promise as a customized emergency vibration detector. The two goals are very different and it is expected that different software programs will be executed for each function. While a fast Fourier transform (FFT) signature under given operating conditions can yield much information regarding turbine condition, the sampling period and processing requirements make it inappropriate for emergency condition monitoring. This paper briefly reviews the development of prototype DSP and accelerometer hardware. More importantly, it reviews our work to design prototype vibration alarm filters. Two-axis accelerometer test data from the experimental FloWind vertical axis wind turbine is analyzed and used as a development guide. Two levels of signal processing are considered. The first uses narrow band pre-processing filters at key fundamental frequencies such as the 1P, 2P and 3P. The total vibration energy in each frequency band is calculated and evaluated as a possible alarm trigger. In the second level of signal processing, the total vibration energy in each frequency band is further decomposed using the two-axis directional information. Directional statistics are calculated to differentiate between linear translations and circular translations. After analyzing the acceleration statistics for normal and unusual operating conditions, the acceleration processing system described could be used in automatic early detection of fault conditions. 9 figs.

  19. Introduction to transfer lines and circular machines

    International Nuclear Information System (INIS)

    Bryant, P.J.

    1984-01-01

    This course was given in the 1983-84 Academic Training Programme. It is designed as an elementary introduction to both the theory and the hardware for transfer lines and circular machines. The course is limited to linear problems and treates the topics of single particle motion in the transverse and longitudinal planes, emittance ellipses, parameterisation, optical properties of some specific modules, stabilities in the transverse and longitudinal planes, field and gradient errors, and scattering in thin windows. (orig.)

  20. Notas sobre una escuela circular prefabricada

    Directory of Open Access Journals (Sweden)

    Neutra, Richard J.

    1961-09-01

    Full Text Available En 1930, la idea de una planta circular para escuela, abarcando un espacio exterior frente a un edificio de usos varios, era ya antigua por lo menos en diez años. El Museo de Arte Moderno de Nueva York, que por aquellos tiempos instaló y preparó en sus nuevas dependencias la primera exposición masiva de Arquitectura moderna, dispuso una magnífica maqueta de este proyecto de Richard J. Neutra.

  1. Circular Intensity Differential Scattering of chiral molecules

    Energy Technology Data Exchange (ETDEWEB)

    Bustamante, C.J.

    1980-12-01

    In this thesis a theory of the Circular Intensity Differential Scattering (CIDS) of chiral molecules as modelled by a helix oriented with respect to the direction of incidence of light is presented. It is shown that a necessary condition for the existence of CIDS is the presence of an asymmetric polarizability in the scatterer. The polarizability of the scatterer is assumed generally complex, so that both refractive and absorptive phenomena are taken into account.

  2. Self-organization in circular shear layers

    DEFF Research Database (Denmark)

    Bergeron, K.; Coutsias, E.A.; Lynov, Jens-Peter

    1996-01-01

    Experiments on forced circular shear layers performed in both magnetized plasmas and in rotating fluids reveal qualitatively similar self-organization processes leading to the formation of patterns of coherent vortical structures with varying complexity. In this paper results are presented from...... both weakly nonlinear analysis and full numerical simulations that closely reproduce the experimental observations. Varying the Reynolds number leads to bifurcation sequences accompanied by topological changes in the distribution of the coherent structures as well as clear transitions in the total...

  3. Magnetic circular dichroism in electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Rusz, Ján; Novák, Pavel; Rubino, S.; Hébert, C.; Schattschneider, P.

    2008-01-01

    Roč. 113, č. 1 (2008), s. 599-604 ISSN 0587-4246. [CSMAG'07. Košice, 09.07.2007-12.07.2007] EU Projects: European Commission(XE) 508971 - CHIRALTEM Institutional research plan: CEZ:AV0Z10100521 Keywords : magnetic circular dichroism * electron microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.321, year: 2008

  4. Off-axis Modal Active Vibration Control Of Rotational Vibrations

    NARCIS (Netherlands)

    Babakhani, B.; de Vries, Theodorus J.A.; van Amerongen, J.

    Collocated active vibration control is an effective and robustly stable way of adding damping to the performance limiting vibrations of a plant. Besides the physical parameters of the Active Damping Unit (ADU) containing the collocated actuator and sensor, its location with respect to the

  5. How to Assess Product Performance in the Circular Economy? Proposed Requirements for the Design of a Circularity Measurement Framework

    OpenAIRE

    Saidani , Michael; YANNOU , Bernard; Leroy , Yann; Cluzel , François

    2017-01-01

    International audience; Assessing product circularity performance is not straightforward. Meanwhile, it gains increasingly importance for businesses and industrial practitioners who are willing to effectively take benefits from circular economy promises. Thus, providing methods and tools to evaluate then enhance product performance—in the light of circular economy—becomes a significant but still barely addressed topic. Following a joint agreement on the need to measure product circularity per...

  6. Forming Of Spherical Titanium Cups From Circular Blanks With Cutouts On The Perimeter

    Directory of Open Access Journals (Sweden)

    Lacki P.

    2015-06-01

    Full Text Available Despite substantial demand for drawn parts made of high-strength sheet metal (including titanium alloys observed in the modern industry, particularly automotive and aviation, their application remains insignificant. This results from the fact that such sheet metal shows poor plasticity and its cold-forming is almost impossible. Low drawability makes it impossible to obtain even such simple shapes as spherical cups. The authors of this study developed circular sheet-metal blanks with cutouts on their perimeter. The blanks allow for cold forming of spherical cups from Ti6Al4V titanium alloy sheet metal using conventional rigid tools. The cutouts proposed in the study affect plastic strain distribution, which in turn leads to an increase in forming depth by about 30%. The numerical analysis, performed using the PamStamp 2G System software based on finite element method, was verified experimentally.

  7. Difference frequency generation spectroscopy as a vibrational optical activity measurement tool.

    Science.gov (United States)

    Cheon, Sangheon; Cho, Minhaeng

    2009-03-19

    Vibrational optical activity (VOA) of chiral molecules in condensed phases can be studied by using vibrational circular dichroism and Raman optical activity measurement techniques. Recently, IR-vis sum frequency generation has shown to be an alternative VOA measurement method. Such a three-wave-mixing method employing a polarization modulation technique can be a potentially useful VOA measurement tool. Here, a theoretical description of difference frequency generation (DFG) employing circularly polarized visible radiations is presented. Frequency scanning to obtain a VOA-DFG spectrum is achieved by controlling the difference between the two electronically nonresonant incident radiation frequencies. If the two incident beams are linearly polarized and their polarization directions are perpendicular to each other, one can selectively measure the all-electric-dipole-allowed chiral component of the DFG susceptibility. In addition, by using circularly polarized beams and taking the DFG difference intensity signal, which is defined as the difference between left and right circularly polarized DFG signals, additional chiral susceptibility components originating from the electric quadrupole transition can be measured. The DFG as a novel VOA measurement technique for solution samples containing chiral molecules will therefore be a useful coherent spectroscopic tool for determining absolute configuration of chiral molecules in condensed phases.

  8. FROM CIRCULAR ECONOMY TO BLUE ECONOMY

    Directory of Open Access Journals (Sweden)

    Iustin-Emanuel, ALEXANDRU

    2014-11-01

    Full Text Available Addressing the subject of this essay is based on the background ideas generated by a new branch of science - Biomimicry. According to European Commissioner for the Environment, "Nature is the perfect model of circular economy". Therefore, by imitating nature, we are witnessing a process of cycle redesign: production-consumption-recycling. The authors present some reflections on the European Commission's decision to adopt after July 1, 2014 new measures concerning the development of more circular economies. Starting from the principles of Ecolonomy, which is based on the whole living paradigm, this paper argues for the development within each economy of entrepreneurial policies related to the Blue economy. In its turn, Blue economy is based on scientific analyses that identify the best solutions in a business. Thus, formation of social capital will lead to healthier and cheaper products, which will stimulate entrepreneurship. Blue economy is another way of thinking economic practice and is a new model of business design. It is a healthy, sustainable business, designed for people. In fact, it is the core of the whole living paradigm through which, towards 2020, circular economy will grow more and more.

  9. Development of circular filters for active facilities

    International Nuclear Information System (INIS)

    Pratt, R.P.

    1986-01-01

    An assessment of problems associated with remote handling, changing and disposal of filters suggested that significant improvements to filtration systems could be made if circular geometries were adopted in place of conventional systems. Improved systems have been developed and are now available for a range of applications and air flow rates. Where primary filters are installed within the active cell or cave, circular filters incorporating a lip seal have been developed which enable the filters to be sealed into the facility without recourse to clamping. For smaller cells, a range of push-through filter change systems have been developed, the principal feature being that the filter is passed into the housing from the clean side, but transferred from the housing directly into the cell for subsequent disposal. For plant room applications, circular bag change canister systems have been developed which ease the sealing and bag change operation. Such systems have a rated air flow of up to 3000 m 3 /h whilst still allowing ultimate disposal via the 200 litre waste drum route without prior volume reduction of the filter inserts. (author)

  10. Application of circular polarized synchrotron radiation

    International Nuclear Information System (INIS)

    Miyahara, Tsuneaki; Kawata, Hiroshi

    1988-03-01

    The idea of using the polarizing property of light for physical experiment by controlling it variously has been known from old time, and the Faraday effect and the research by polarizing microscopy are its examples. The light emitted from the electron orbit of an accelerator has the different polarizing characteristics from those of the light of a laboratory light source, and as far as observing it within the electron orbit plane, it becomes linearly polarized light. By utilizing this property well, research is carried out at present in synchrotron experimental facilities. Recently, the technology related to the insert type light cources using permanent magnets has advanced remarkably, and circular polarized light has become to be producible. If the light like this can be obtained with the energy not only in far ultraviolet region but also to x-ray region at high luminance, new possibility should open. At the stage that the design of an insert type light source was finished, and its manufacture was started, the research on the method of evaluating the degree of circular polarization and the research on the utilization of circular polarized synchrotron radiation are earnestly carried out. In this report, the results of researches presented at the study meeting are summarized. Moreover, the design and manufacture of the beam lines for exclusive use will be carried out. (Kako, I.)

  11. System for circular and complex tomography

    International Nuclear Information System (INIS)

    Hellstrom, M.J.

    1979-01-01

    This invention discloses a system for conducting circular as well as complex tomographic procedures utilizing apparatus which has no mechanical linkage between the X-ray source and the X-ray receptor. The path of travel of the X-ray source both circularly and linearly is sensed by electromagnetic radiation and more particularly by light radiation which is generated by a laser. The linear travel is sensed by means of reflected laser radiation directed to the X-ray source and fed to an interferometer. The circular travel, on the other hand, is sensed by means of a laser gyroscope also receiving light radiation from a laser. Optical energy sensing means is thus used to generate command signals which are coupled to respective drive motors which act to rotate and when desirable, translate the X-ray receptor so that its motion follows the motion, both orbital and linear, of the X-ray source for performing any desired type of tomographic procedure

  12. Surface vibrational spectroscopy (EELS)

    International Nuclear Information System (INIS)

    Okuyama, Hiroshi

    2006-01-01

    Adsorbed states of hydrogen on metal surfaces have been studied by means of electron energy loss spectroscopy (EELS). In this article, typical spectra and analysis as well as recent development are introduced. (author)

  13. Architectural Surfaces and Structures from Circular Arcs

    KAUST Repository

    Shi, Ling

    2013-12-01

    In recent decades, the popularity of freeform shapes in contemporary architecture poses new challenges to digital design. One of them is the process of rationalization, i.e. to make freeform skins or structures affordable to manufacture, which draws the most attention from geometry researchers. In this thesis, we aim to realize this process with simple geometric primitives, circular arcs. We investigate architectural surfaces and structures consisting of circular arcs. Our focus is lying on how to employ them nicely and repetitively in architectural design, in order to decrease the cost in manufacturing. Firstly, we study Darboux cyclides, which are algebraic surfaces of order ≤ 4. We provide a computational tool to identify all families of circles on a given cyclide based on the spherical model of M ̈obius geometry. Practical ways to design cyclide patches that pass through certain inputs are presented. In particular, certain triples of circle families on Darboux cyclides may be suitably arranged as 3-webs. We provide a complete classification of all possible 3-webs of circles on Darboux cyclides. We then investigate the circular arc snakes, which are smooth sequences of circu- lar arcs. We evolve the snakes such that their curvature, as a function of arc length, remains unchanged. The evolution of snakes is utilized to approximate given surfaces by circular arcs or to generated freeform shapes, and it is realized by a 2-step pro- cess. More interestingly, certain 6-arc snake with boundary constraints can produce a smooth self motion, which can be employed to build flexible structures. Another challenging topic is approximating smooth freeform skins with simple panels. We contribute to this problem area by approximating a negatively-curved 5 surface with a smooth union of rational bilinear patches. We provide a proof for vertex consistency of hyperbolic nets using the CAGD approach of the rational B ́ezier form. Moreover, we use Darboux transformations for the

  14. Vibrational spectra of ordered perovskites

    NARCIS (Netherlands)

    Corsmit, A.F.; Hoefdraad, H.E.; Blasse, G.

    1972-01-01

    The vibrational spectra of the molecular M6+O6 (M = Mo, Te, W) group in ordered perovskites of the type Ba2M2+M6+O6 are reported. These groups have symmetry Oh, whereas their site symmetry is also Oh. An assignment of the internal vibrations is presented.

  15. Vibrations and Stability: Solved Problems

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003.......Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003....

  16. Parallel two-phase-flow-induced vibrations in fuel pin model

    International Nuclear Information System (INIS)

    Hara, Fumio; Yamashita, Tadashi

    1978-01-01

    This paper reports the experimental results of vibrations of a fuel pin model -herein meaning the essential form of a fuel pin from the standpoint of vibration- in a parallel air-and-water two-phase flow. The essential part of the experimental apparatus consisted of a flat elastic strip made of stainless steel, both ends of which were firmly supported in a circular channel conveying the two-phase fluid. Vibrational strain of the fuel pin model, pressure fluctuation of the two-phase flow and two-phase-flow void signals were measured. Statistical measures such as power spectral density, variance and correlation function were calculated. The authors obtained (1) the relation between variance of vibrational strain and two-phase-flow velocity, (2) the relation between variance of vibrational strain and two-phase-flow pressure fluctuation, (3) frequency characteristics of variance of vibrational strain against the dominant frequency of the two-phase-flow pressure fluctuation, and (4) frequency characteristics of variance of vibrational strain against the dominant frequency of two-phase-flow void signals. The authors conclude that there exist two kinds of excitation mechanisms in vibrations of a fuel pin model inserted in a parallel air-and-water two-phase flow; namely, (1) parametric excitation, which occurs when the fundamental natural frequency of the fuel pin model is related to the dominant travelling frequency of water slugs in the two-phase flow by the ratio 1/2, 1/1, 3/2 and so on; and (2) vibrational resonance, which occurs when the fundamental frequency coincides with the dominant frequency of the two-phase-flow pressure fluctuation. (auth.)

  17. DYNAMICS OF VIBRATION FEEDERS WITH A NONLINEAR ELASTIC CHARACTERISTIC

    Directory of Open Access Journals (Sweden)

    V. I. Dyrda

    2017-04-01

    Full Text Available Purpose. Subject to the smooth and efficient operation of each production line, is the use of vehicles transporting high specification. It worked well in practice for transporting construction machines, which are used during the vibration. The use of vibration machines requires optimization of their operation modes. In the form of elastic link in them are increasingly using rubber-metallic elements, which are characterized by nonlinear damping properties. So it is necessary to search for new, more modern, methods of calculation of dynamic characteristics of the vibration machines on the properties of rubber as a cushioning material. Methodology. The dynamics of vibration machine that is as elastic rubber block units and buffer shock absorbers limiting the amplitude of the vibrations of the working body. The method of determining amplitude-frequency characteristics of the vibrating feeder is based on the principle of Voltaire, who in the calculations of the damping properties of the dampers will allow for elastic-hereditary properties of rubber. When adjusting the basic dynamic stiffness of the elastic ties and vibratory buffers, using the principle of heredity rubber properties, determine the dependence of the amplitude of the working body of the machine vibrations. This method is called integro-operator using the fractional-exponential kernels of relaxation. Findings. Using the derived formula for determining the amplitude of the resonance curve is constructed one-mass nonlinear system. It is established that the use of the proposed method of calculation will provide a sufficiently complete description of the damping parameters of rubber-metallic elements and at the same time be an effective means of calculating the amplitude-frequency characteristics of nonlinear vibration systems. Originality. The authors improved method of determining damping characteristics of rubber-metallic elements and the amplitude-frequency characteristics of nonlinear

  18. Circular RNAs as Promising Biomarkers: A mini-review

    Directory of Open Access Journals (Sweden)

    Nadiah Abu

    2016-08-01

    Full Text Available The interest in circular RNAs has resurfaced in the past few years. What was considered as junk for nearly two decades is now one of the most interesting molecules. Circular RNAs are non-coding RNAs that are formed by back-splicing events and have covalently closed loops with no poly-adenylated tails. The regulation of circular RNAs is distinctive and they are selectively abundant in different types of tissues. Based on the current knowledge of circular RNAs, these molecules have the potential to be the next big thing especially as biomarkers for different diseases. This mini-review attempts to concisely look at the biology of circular RNAs, the putative functional activities, the prevalence of circular RNAs, and the possible role of circular RNA as biomarkers for diagnosis or measuring drug response.

  19. Low Cost Digital Vibration Meter.

    Science.gov (United States)

    Payne, W Vance; Geist, Jon

    2007-01-01

    This report describes the development of a low cost, digital Micro Electro Mechanical System (MEMS) vibration meter that reports an approximation to the RMS acceleration of the vibration to which the vibration meter is subjected. The major mechanical element of this vibration meter is a cantilever beam, which is on the order of 500 µm in length, with a piezoresistor deposited at its base. Vibration of the device in the plane perpendicular to the cantilever beam causes it to bend, which produces a measurable change in the resistance of a piezoresistor. These changes in resistance along with a unique signal-processing scheme are used to determine an approximation to the RMS acceleration sensed by the device.

  20. Forces in Liquid Metal Contacts

    DEFF Research Database (Denmark)

    Duggen, Lars; Mátéfi-Tempfli, Stefan

    2014-01-01

    Using rather well known theory about capillary bridges between two electrodes we calculate the tensile force that can be applied to liquid metal contacts in the micrometer regime. Assuming circular symmetry, full wetting of the electrodes, and neglecting gravity, we present a brief review of the ...... of the necessary theory and find numerically the forces to be in the 100μN range for liquid metals as mercury and liquid Gallium suspended between electrodes of 20μm radius.......Using rather well known theory about capillary bridges between two electrodes we calculate the tensile force that can be applied to liquid metal contacts in the micrometer regime. Assuming circular symmetry, full wetting of the electrodes, and neglecting gravity, we present a brief review...

  1. Wavelength dependent photoelectron circular dichroism of limonene studied by femtosecond multiphoton laser ionization and electron-ion coincidence imaging

    Science.gov (United States)

    Rafiee Fanood, Mohammad M.; Janssen, Maurice H. M.; Powis, Ivan

    2016-09-01

    Enantiomers of the monoterpene limonene have been investigated by (2 + 1) resonance enhanced multiphoton ionization and photoelectron circular dichroism employing tuneable, circularly polarized femtosecond laser pulses. Electron imaging detection provides 3D momentum measurement while electron-ion coincidence detection can be used to mass-tag individual electrons. Additional filtering, by accepting only parent ion tagged electrons, can be then used to provide discrimination against higher energy dissociative ionization mechanisms where more than three photons are absorbed to better delineate the two photon resonant, one photon ionization pathway. The promotion of different vibrational levels and, tentatively, different electronic ion core configurations in the intermediate Rydberg states can be achieved with different laser excitation wavelengths (420 nm, 412 nm, and 392 nm), in turn producing different state distributions in the resulting cations. Strong chiral asymmetries in the lab frame photoelectron angular distributions are quantified, and a comparison made with a single photon (synchrotron radiation) measurement at an equivalent photon energy.

  2. The role of ro-vibrational coupling in the revival dynamics of diatomic molecular wave packets

    International Nuclear Information System (INIS)

    Banerji, J; Ghosh, Suranjana

    2006-01-01

    We study the revival and fractional revivals of a diatomic molecular wave packet of circular states whose weighing coefficients are peaked about a vibrational quantum number ν-bar and a rotational quantum number j-bar. Furthermore, we show that the interplay between the rotational and vibrational motion is determined by a parameter γ =√D/C, where D is the dissociation energy and C is inversely proportional to the reduced mass of the two nuclei. Using I 2 and H 2 as examples, we show, both analytically and visually (through animations), that for γ>>ν-bar, j-bar, the rotational and vibrational time scales are so far apart that the ro-vibrational motion gets decoupled and the revival dynamics depends essentially on one time scale. For γ∼ν-bar, j-bar, on the other hand, the evolution of the wave packet depends crucially on both the rotational and vibrational time scales of revival. In the latter case, an interesting rotational-vibrational fractional revival is predicted and explained

  3. Transformation of vibration signals in rotary blood pumps: the diagnostic potential of pump failure.

    Science.gov (United States)

    Kawahito, Koji

    2013-09-01

    Although non-destructive and continuous monitoring is indispensable for long-term circulatory support with rotary blood pumps, a practical monitoring system has not yet been developed. The objective of this study was to investigate the possibility of detecting pump failure caused by thrombus formation through the monitoring of vibration signals. The data acquisition equipment included vibration pickups, a charge amplifier, vibration analysis systems, and exclusive hardware. A pivot-bearing centrifugal pump with a mock circuit was investigated for vibration analysis. To simulate the four common areas of thrombus formation, we used a piece of silicon attached to each of the following four locations: the total area of the bottom of the impeller, an eccentric shape on the bottom of the impeller, a circular shape around the shaft top, and an eccentric shape on the top of the impeller. Vibration signals were picked up, and the power spectrum density analysis was performed at pump rotational speeds of 2100, 2400, and 3000 rpm. In this study, pump failure could be detected, and the types of imitation thrombi could be determined. We conclude that vibration detection with a computerized analysis system is a potentially valuable diagnostic tool for long-term circulatory support with rotary blood pumps.

  4. Vibration properties of a rotating piezoelectric energy harvesting device that experiences gyroscopic effects

    Science.gov (United States)

    Lu, Haohui; Chai, Tan; Cooley, Christopher G.

    2018-03-01

    This study investigates the vibration of a rotating piezoelectric device that consists of a proof mass that is supported by elastic structures with piezoelectric layers. Vibration of the proof mass causes deformation in the piezoelectric structures and voltages to power the electrical loads. The coupled electromechanical equations of motion are derived using Newtonian mechanics and Kirchhoff's circuit laws. The free vibration behavior is investigated for devices with identical (tuned) and nonidentical (mistuned) piezoelectric support structures and electrical loads. These devices have complex-valued, speed-dependent eigenvalues and eigenvectors as a result of gyroscopic effects caused by their constant rotation. The characteristics of the complex-valued eigensolutions are related to physical behavior of the device's vibration. The free vibration behaviors differ significantly for tuned and mistuned devices. Due to gyroscopic effects, the proof mass in the tuned device vibrates in either forward or backward decaying circular orbits in single-mode free response. This is proven analytically for all tuned devices, regardless of the device's specific parameters or operating speed. For mistuned devices, the proof mass has decaying elliptical forward and backward orbits. The eigenvalues are shown to be sensitive to changes in the electrical load resistances. Closed-form solutions for the eigenvalues are derived for open and close circuits. At high rotation speeds these devices experience critical speeds and instability.

  5. Computational simulations of hydrogen circular migration in protonated acetylene induced by circularly polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xuetao; Li, Wen; Schlegel, H. Bernhard, E-mail: hbs@chem.wayne.edu [Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States)

    2016-08-28

    The hydrogens in protonated acetylene are very mobile and can easily migrate around the C{sub 2} core by moving between classical and non-classical structures of the cation. The lowest energy structure is the T-shaped, non-classical cation with a hydrogen bridging the two carbons. Conversion to the classical H{sub 2}CCH{sup +} ion requires only 4 kcal/mol. The effect of circularly polarized light on the migration of hydrogens in oriented C{sub 2}H{sub 3}{sup +} has been simulated by Born-Oppenheimer molecular dynamics. Classical trajectory calculations were carried out with the M062X/6-311+G(3df,2pd) level of theory using linearly and circularly polarized 32 cycle 7 μm cosine squared pulses with peak intensity of 5.6 × 10{sup 13} W/cm{sup 2} and 3.15 × 10{sup 13} W/cm{sup 2}, respectively. These linearly and circularly polarized pulses transfer similar amounts of energy and total angular momentum to C{sub 2}H{sub 3}{sup +}. The average angular momentum vectors of the three hydrogens show opposite directions of rotation for right and left circularly polarized light, but no directional preference for linearly polarized light. This difference results in an appreciable amount of angular displacement of the three hydrogens relative to the C{sub 2} core for circularly polarized light, but only an insignificant amount for linearly polarized light. Over the course of the simulation with circularly polarized light, this corresponds to a propeller-like motion of the three hydrogens around the C{sub 2} core of protonated acetylene.

  6. Lattice vibration spectra. 16

    International Nuclear Information System (INIS)

    Lutz, H.D.; Willich, P.

    1977-01-01

    The FIR absorption spectra of pyrite type compounds RuS 2 , RuSsub(2-x)Sesub(x), RuSe 2 , RuTe 2 , OsS 2 , OsSe 2 , and PtP 2 as well as loellingite type phosphides FeP 2 , RuP 2 , and OsP 2 are reported. For RuS 2 , RuSe 2 , RuTe 2 , OsS 2 , and PtP 2 all of the five infrared allowed modes (k = 0) are observed. As a first result of a numerical normal coordinate treatment vibration forms of pyrite structure are communicated. The spectra show that lattice forces of corresponding sulfides, tellurides, and phosphides are about the same strength, but increase strongly by substitution of iron by ruthenium and especially of ruthenium by osmium. The lattice constants of the RuSsub(2-x)Sesub(x) solid solution obey Vegard's rule. (author)

  7. Propagation and radiation characteristics of the circular electric, circular magnetic and hybrid waveguide modes

    International Nuclear Information System (INIS)

    Crenn, J.P.

    1996-06-01

    The field distributions and propagation constants of the circular electric, circular magnetic and hybrid modes of oversized waveguides are expressed, taking the effects of walls into account. The near and far field patterns are derived in the case of real wall functions. It is shown that, for very oversized waveguides, the terms containing wall functions can be ignored in the calculations, and it results that the expressions of fields and propagation constants become independent of the types of waveguides. An application to corrugated waveguides for Electron Cyclotron Resonance Heating experiments shows the variations of the radiation characteristics versus geometric parameters of the corrugations and determines the ranges of interest for these parameters. (author)

  8. A comprehensive model for in-plane and out-of-plane vibration of CANDU fuel endplate rings

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S.D., E-mail: syu@ryerson.ca; Fadaee, M.

    2016-08-01

    Highlights: • Proposed an effective method for modelling bending and torsional vibration of CANDU fuel endplate rings. • Applied successfully the thick plate theory to curved structural members by accounting for the transverse shear effect. • The proposed method is computationally more efficient compared to the 3D finite element. - Abstract: In this paper, a comprehensive vibration model is developed for analysing in-plane and out-of-plane vibration of CANDU fuel endplate rings by taking into consideration the effects of in-plane extension in the circumferential and radial directions, shear, and rotatory inertia. The model is based on Reddy’s thick plate theory and the nine-node isoparametric Lagrangian plate finite elements. Natural frequencies of various modes of vibration of circular rings obtained using the proposed method are compared with 3D finite element results, experimental data and results available in the literature. Excellent agreement was achieved.

  9. [Haikou issues circular on planned parenthood].

    Science.gov (United States)

    1981-02-03

    The Organization Department of the Haikou Municipal CCP Committee, the municipal grain, finance, commerce, education bureau, personnel, public security, labor, civil affairs, public health, and housing bureaus, supply and marketing cooperative, and planned parenthood office recently issued a joint circular on implementing the provincial planned parenthood regulations. The circular demanded that the marriage registration and census system be seriously implemented. When people are registering for marriage, we must teach them to have only 1 child. We must give priority in housing and employment to an only child and his parents. When commercial, supply, and marketing departments are distributing coupons for fuel, and nonstaple food, they should supply a double amount to the only child. We must carry out serious health care for an only child and give them regular physical check-ups. When they are ill, hospitals should give them priority in registration, treatment, reservation of beds and medicines. The circular reiterated: We must seriously implement the stipulations on rewards and punishments contained in the provincial planned parenthood regulations. Cadres, staff, or workers who apply to have only 1 child must be given lump sums in addition to enjoying the relevant rewards stipulated by the regulations. Cadres, staff, workers, inhabitants, and commune workers who depend on state grain who violate the regulations must be punished according to the regulation. As for those who have 3 or more than 3 children, a 2nd child without planning, or an illegitimate child, the child's grain ration will be sold at negotiated price up to the age of 14. The grain department will distribute to them a supply ticket for negotiated price grain to buy grain in assigned grain shops. full text

  10. MHD stability of an almost circular tokamak

    International Nuclear Information System (INIS)

    Roy, A.

    1990-10-01

    In a tokamak, the ratio β between the plasma pressure and that of the magnetic field is limited by the appearance of instabilities. The magnetic field in a tokamak reactor will always be limited by technological constraints. It is therefore crucial to know what factors have an effect on the β limit, since a zero resistivity plasma fluid model allows for theoretical reproduction of the β limits observed experimentally. Theoretical studies have shown that the distributions of pressure and current density may have a substantial effect on the β limit. The effect of the current density and pressure distributions on the β limit has been studied for tokamak with a circular core section. The best results are obtained when the current density is concentrated in the centre of the section and is nil at the periphery. But the second region of stability against ballooning modes cannot be obtained in a circular tokamak owing to the destabilisation of the universal modes. This study was then extended to the stability of plasmas the section of which is almost circular and has a point of reflection. Such configurations are vital for fusion since they allow systems in which the confinement time does not deteriorate with an increase in the additional heating power. The β limit was calculated for different positions of the reflection point. The results show that when it is displaced from the interior towards the exterior of the torus, the stability of the overall modes is progressively improved until it is vertical. But if the point of reflection is further displaced from this vertical position towards the exterior of the torus, localised modes close to the edge of the plasma are destabilised and bring about a drop in the β limit. (author) figs., tabs., 80 refs

  11. Multipole Analysis of Circular Cylindircal Magnetic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Selvaggi, Jerry P. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2005-12-01

    This thesis deals with an alternate method for computing the external magnetic field from a circular cylindrical magnetic source. The primary objective is to characterize the magnetic source in terms of its equivalent multipole distribution. This multipole distribution must be valid at points close to the cylindrical source and a spherical multipole expansion is ill-equipped to handle this problem; therefore a new method must be introduced. This method, based upon the free-space Green's function in cylindrical coordinates, is developed as an alternative to the more familiar spherical harmonic expansion. A family of special functions, called the toroidal functions or Q-functions, are found to exhibit the necessary properties for analyzing circular cylindrical geometries. In particular, the toroidal function of zeroth order, which comes from the integral formulation of the free-space Green's function in cylindrical coordinates, is employed to handle magnetic sources which exhibit circular cylindrical symmetry. The toroidal functions, also called Q-functions, are the weighting coefficients in a ''Fourier series-like'' expansion which represents the free-space Green's function. It is also called a toroidal expansion. This expansion can be directly employed in electrostatic, magnetostatic, and electrodynamic problems which exhibit cylindrical symmetry. Also, it is shown that they can be used as an alternative to the Elliptic integral formulation. In fact, anywhere that an Elliptic integral appears, one can replace it with its corresponding Q-function representation. A number of problems, using the toroidal expansion formulation, are analyzed and compared to existing known methods in order to validate the results. Also, the equivalent multipole distribution is found for most of the solved problems along with its corresponding physical interpretation. The main application is to characterize the external magnetic field due to a six

  12. Chiral surface waves for enhanced circular dichroism

    Science.gov (United States)

    Pellegrini, Giovanni; Finazzi, Marco; Celebrano, Michele; Duò, Lamberto; Biagioni, Paolo

    2017-06-01

    We present a novel chiral sensing platform that combines a one-dimensional photonic crystal design with a birefringent surface defect. The platform sustains simultaneous transverse electric and transverse magnetic surface modes, which are exploited to generate chiral surface waves. The present design provides homogeneous and superchiral fields of both handednesses over arbitrarily large areas in a wide spectral range, resulting in the enhancement of the circular dichroism signal by more than two orders of magnitude, thus paving the road toward the successful combination of surface-enhanced spectroscopies and electromagnetic superchirality.

  13. Vortex Shedding from Finned Circular Cylinders

    Science.gov (United States)

    1980-11-01

    FINNED CIRCULAR CYLINDERSo ,rm"" 1..UTNOI .)R*., r. *.040, 111SPOR- / T NuMBII f.John G. elute asOHans J.’/, ugt -. . . , ,<-. -. ,:. =., .. Siil P3RPIO...fins and other sharp protuberances. These purely two-dimensional flows then may be used in a strip theory to include at least some aspects of three...boundary- layer theory . Such a prediction method, together with a technique to provide for a vortex sheet at the separation point, will be included in

  14. Future Circular Collider study week 2017

    CERN Document Server

    2017-01-01

    The annual meetings of the worldwide Future Circular Collider study (FCC) are major international events that review the progress in every domain which is relevant to develop feasible concepts for a next generation frontier particle accelerate based high-energy physics research infrastructure. This 3rd meeting is jointly organised by CERN and DESY. It is also the annual meeting of the EuroCirCol EC Horizon 2020 Research and Innovation Action project. Previous events took place in Washington and Rome. In 2017 the FCC Week will take place in Berlin, Germany between May 29 and June 2.

  15. Porphyrin Protonation Studied by Magnetic Circular Dichroism

    Czech Academy of Sciences Publication Activity Database

    Štěpánek, Petr; Andrushchenko, Valery; Ruud, K.; Bouř, Petr

    2012-01-01

    Roč. 116, č. 1 (2012), s. 778-783 ISSN 1089-5639 R&D Projects: GA ČR GAP208/11/0105; GA ČR GA203/09/2037; GA ČR GAP208/10/0559; GA MŠk(CZ) LH11033 Institutional research plan: CEZ:AV0Z40550506 Keywords : magnetic circular dichroism ( MCD ) * TPPS * spectra simulations * porphyrin protonation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.771, year: 2012

  16. A Circularly Arranged Sextuple Triptycene Gear Molecule.

    Science.gov (United States)

    Ube, Hitoshi; Yamada, Ryo; Ishida, Jun-Ichi; Sato, Hiroyasu; Shiro, Motoo; Shionoya, Mitsuhiko

    2017-11-22

    Herein we report the synthesis of a circularly arranged sextuple triptycene gear molecule, hexakis(10-dodecyloxy-9-triptycyl)ethynylbenzene, via the trimerization of the corresponding triyne with a cobalt catalyst. The six triptycene gears are closely engaged with each other as confirmed by single crystal X-ray structure analysis, and their motion in solution was established by NMR spectroscopy. Notably, when one bulky RuCp* complex was attached to one triptycene gear, the whole movement of the six gears was highly restricted via their mechanical engagement. Development of such a multigear molecule would provide a structural basis for molecular motion transmission systems with a switching function.

  17. Vibrational Spectroscopy of Ionic Liquids.

    Science.gov (United States)

    Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

    2017-05-24

    Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

  18. Vibration and Operational Characteristics of a Composite-Steel (Hybrid) Gear

    Science.gov (United States)

    Handschuh, Robert F.; LaBerge, Kelsen E.; DeLuca, Samuel; Pelagalli, Ryan

    2014-01-01

    Hybrid gears have been tested consisting of metallic gear teeth and shafting connected by composite web. Both free vibration and dynamic operation tests were completed at the NASA Glenn Spur Gear Fatigue Test Facility, comparing these hybrid gears to their steel counterparts. The free vibration tests indicated that the natural frequency of the hybrid gear was approximately 800 Hz lower than the steel test gear. The dynamic vibration tests were conducted at five different rotational speeds and three levels of torque in a four square test configuration. The hybrid gears were tested both as fabricated (machined, composite layup, then composite cure) and after regrinding the gear teeth to the required aerospace tolerance. The dynamic vibration tests indicated that the level of vibration for either type of gearing was sensitive to the level of load and rotational speed.

  19. Intense Vibronic Modulation of the Chiral Photoelectron Angular Distribution Generated by Photoionization of Limonene Enantiomers with Circularly Polarized Synchrotron Radiation.

    Science.gov (United States)

    Rafiee Fanood, Mohammad M; Ganjitabar, Hassan; Garcia, Gustavo A; Nahon, Laurent; Turchini, Stefano; Powis, Ivan

    2018-04-17

    Photoionization of the chiral monoterpene limonene has been investigated using polarized synchrotron radiation between the adiabatic ionization threshold, 8.505 and 23.5 eV. A rich vibrational structure is seen in the threshold photoelectron spectrum and is interpreted using a variety of computational methods. The corresponding photoelectron circular dichroism-measured in the photoelectron angular distribution as a forward-backward asymmetry with respect to the photon direction-was found to be strongly dependent on the vibronic structure appearing in the photoelectron spectra, with the observed asymmetry even switching direction in between the major vibrational peaks. This effect can be ultimately attributed to the sensitivity of this dichroism to small phase shifts between adjacent partial waves of the outgoing photoelectron. These observations have implications for potential applications of this chiroptical technique, where the enantioselective analysis of monoterpene components is of particular interest. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Astronomy in Denver: Probing Interstellar Circular Polarization with Polvis, a Full Stokes Single Shot Polarimeter

    Science.gov (United States)

    Wolfe, Tristan; Stencel, Robert E.

    2018-06-01

    Measurements of optical circular polarization (Stokes V) introduced by dust grains in the ISM are important for two main reasons. First of all, the polarization itself contains information about the metallic versus dielectric composition of the dust grains themselves (H. C. van de Hulst 1957, textbook). Additionally, circular polarization can help constrain the interstellar component of the polarization of any source that may have intrinsic polarization, which needs to be calibrated for astrophysical study. Though interstellar circular polarization has been observed (P. G. Martin 1972, MNRAS 159), most broadband measurements of ISM polarization include linear polarization only (Stokes Q and U), due to the relatively low circular polarization signal and the added instrumentation complexity of including V-measurement capability. Prior circular polarization measurements have also received very little follow-up in the past several decades, even as polarimeters have become more accurate due to advances in technology. The University of Denver is pursuing these studies with POLVIS, a prototype polarimeter that utilizes a stress-engineered optic ("SEO", A. K. Spilman and T. G. Brown 2007, Applied Optics IP 46) to produce polarization-dependent PSFs (A. M. Beckley and T. G. Brown 2010, Proc SPIE 7570). These PSFs are analyzed to provide simultaneous Stokes I, Q, U, and V measurements, in a single beam and single image, along the line-of-sight to point source-like objects. Polvis is the first polarimeter to apply these optics and measurement techniques for astronomical observations. We present the first results of this instrument in B, V, and R wavebands, providing a fresh look at full Stokes interstellar polarization. Importantly, this set of efforts will constrain the ISM contribution to the polarization with respect to intrinsic stellar components. The authors are grateful to the estate of William Herschel Womble for the support of astronomy at the University of Denver

  1. Molecular vibrations the theory of infrared and Raman vibrational spectra

    CERN Document Server

    Wilson, E Bright; Cross, Paul C

    1980-01-01

    Pedagogical classic and essential reference focuses on mathematics of detailed vibrational analyses of polyatomic molecules, advancing from application of wave mechanics to potential functions and methods of solving secular determinant.

  2. A Study on the Uncertainty of Flow-Induced Vibration in a Cross Flow over Staggered Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji-Su; Park, Jong-Woon [Dongguk univ, Gyeong Ju (Korea, Republic of); Choi, Hyeon-Kyeong [HanNam University, Daejeon (Korea, Republic of)

    2015-05-15

    Cross-flow in many support columns of very high temperature reactor (VHTR) lower plenum would have FIV issues under high speed flow jetting from the core. For a group of multiple circular cylinders subjected to a cross-flow, three types of potential vibration mechanisms may exist: (1) Vortex-induced vibration (VIV), (2) Fluid-elastic vibration (FEV) and (3) Turbulence-induced vibration (TIV). Kevalahan studied the free vibration of circular cylinders in a tightly packed periodic square inline array of cylinders. Pandey et al. studied the flue gas flow distribution in the Low Temperature Super Heater (LTSH) tube bundles situated in second pass of a utility boiler and the phenomenon of flow induced vibration. Nakamura et al. studied flow instability of cylinder arrays resembling U-bend tubes in steam generators. The FIV evaluation is usually performed with computational fluid dynamic (CFD) analysis to obtain unknown frequency of oscillation of the multiple objects under turbulent flow and thus the uncertainty residing in the turbulence model used should be quantified. In this paper, potential FIV uncertainty arising from the turbulence phenomena are evaluated for a typical cross flow through staggered tube bundles resembling the VHTR lower plenum support columns. Flow induced vibration (FIV) is one of the important mechanical and fatigue issues in nuclear systems. Especially, cross-flow in many support structures of VHTR lower plenum would have FIV issues under highly turbulent jet flows from the core. The results show that the effect of turbulence parameters on FIV is not negligible and the uncertainty is 5 to 10%. Present method can be applied to future FIV evaluations of nuclear systems. More extensive studies on flow induced vibration in a plant scale by using more rigorous computational methods are under way.

  3. Synthesis and vibrational spectrum of antimony phosphate, SbPO4.

    Science.gov (United States)

    Brockner, Wolfgang; Hoyer, Lars P

    2002-07-01

    SbPO4 was synthesized via a new route by reacting antimony metal with meta-phosphoric acid, (HPO3)n at high temperatures. The Raman and IR spectra of the title compound were recorded and the vibrational modes assigned on the basis of a factor group analysis. The internal vibrations are derived from tetrahedral PO4 units (approaching Sb[PO4]) by the correlation method, although the structure is polymeric and not ionic.

  4. Plastic deformation of particles of zirconium and titanium carbide subjected to vibration grinding

    Energy Technology Data Exchange (ETDEWEB)

    Kravchik, A.E.; Neshpor, V.S.; Savel' ev, G.A.; Ordan' yan, S.S.

    1976-12-01

    A study is made of the influence of stoichiometry on the characteristics of microplastic deformation in powders of zirconium and titanium carbide subjected to vibration grinding. The carbide powders were produced by direct synthesis from the pure materials: metallic titanium and zirconium and acetylene black. As to the nature of their elastic deformation, zirconium and titanium carbides can be considered elastic-isotropic materials. During vibration grinding, the primary fracture planes are the (110) planes. Carbides of nonstoichiometric composition are more brittle.

  5. Quantum decoherence in electronic current flowing through carbon nanotubes induced by thermal atomic vibrations

    Science.gov (United States)

    Ishizeki, Keisuke; Sasaoka, Kenji; Konabe, Satoru; Souma, Satofumi; Yamamoto, Takahiro

    2018-06-01

    We theoretically investigate quantum decoherence in electronic currents flowing through metallic carbon nanotubes caused by thermal atomic vibrations using the time-dependent Schrödinger equation for an open system. We reveal that the quantum coherence of conduction electrons decays exponentially with tube length at a fixed temperature, and that the decay rate increases with temperature. We also find that the phase relaxation length due to the thermal atomic vibrations is inversely proportional to temperature.

  6. Synchrotron radiation in the Far-Infrared: Adsorbate-substrate vibrations and resonant interactions

    International Nuclear Information System (INIS)

    Hoffmann, F.M.; Williams, G.P.; Hirschmugl, C.J.; Chabal, Y.J.

    1991-01-01

    Synchrotron radiation in the Far Infrared offers the potential for a broadband source of high brightness and intensity. Recent development of a Far-Infrared Beamline at the NSLS in Brookhaven provides an unique high intensity source in the FIR spectral range (800-10 cm -1 ). This talk reviews its application to surface vibrational spectroscopy of low frequency adsorbate-substrate vibrations and resonant interactions on metal surfaces

  7. High Performance Circularly Polarized Microstrip Antenna

    Science.gov (United States)

    Bondyopadhyay, Probir K. (Inventor)

    1997-01-01

    A microstrip antenna for radiating circularly polarized electromagnetic waves comprising a cluster array of at least four microstrip radiator elements, each of which is provided with dual orthogonal coplanar feeds in phase quadrature relation achieved by connection to an asymmetric T-junction power divider impedance notched at resonance. The dual fed circularly polarized reference element is positioned with its axis at a 45 deg angle with respect to the unit cell axis. The other three dual fed elements in the unit cell are positioned and fed with a coplanar feed structure with sequential rotation and phasing to enhance the axial ratio and impedance matching performance over a wide bandwidth. The centers of the radiator elements are disposed at the corners of a square with each side of a length d in the range of 0.7 to 0.9 times the free space wavelength of the antenna radiation and the radiator elements reside in a square unit cell area of sides equal to 2d and thereby permit the array to be used as a phased array antenna for electronic scanning and is realizable in a high temperature superconducting thin film material for high efficiency.

  8. Zernike vs. Bessel circular functions in visual optics.

    Science.gov (United States)

    Trevino, Juan P; Gómez-Correa, Jesus E; Iskander, D Robert; Chávez-Cerda, Sabino

    2013-07-01

    We propose the Bessel Circular Functions as alternatives of the Zernike Circle Polynomials to represent relevant circular ophthalmic surfaces. We assess the fitting capabilities of the orthogonal Bessel Circular Functions by comparing them to Zernike Circle Polynomials for approximating a variety of computationally generated surfaces which can represent ophthalmic surfaces. The Bessel Circular Functions showed better modelling capabilities for surfaces with abrupt variations such as the anterior eye surface at the limbus region, and influence functions. From our studies we find that the Bessel Circular Functions can be more suitable for studying particular features of post surgical corneal surfaces. We show that given their boundary conditions and free oscillating properties, the Bessel Circular Functions are an alternative for representing specific wavefronts and can be better than the Zernike Circle Polynomials for some important cases of corneal surfaces, influence functions and the complete anterior corneal surface. © 2013 The Authors Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

  9. Putting a damper on drilling's bad vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Jardine, S [Sedco forex, Montrouge (France); Malone, D [Anadrill, Sugar Land, TX (United States); Sheppard, M [Schlumberger Cambridge Research, Cambridge (United Kingdom)

    1994-01-01

    Harmful drilling vibrations are costing the industry dearly. Three main vibration types (axial, torsional and transverse) are explained and its causes discussed. Technology exists to eliminate most vibrations, but requires more systematic deployment than is usual. Hardware that eliminates vibrations is reviewed, including downhole shock measurement, torque feedback shock guards and antiwhirl bits. 9 figs., 11 refs.

  10. Influence of Ultrasonic Vibrations on the Static Friction Characteristics of a Rubber/Aluminum Couple

    International Nuclear Information System (INIS)

    Cheng Ting-Hai; Gao Han; Bao Gang

    2011-01-01

    A novel ultrasonic vibration approach is introduced into a chloroprene rubber/aluminum friction couple for improving the static friction properties between rubber and metal. Compared to the test results without vibrations, the static friction force of a chloroprene rubber/aluminum couple decreases observably, leading to the ultimate displacement of rubber. The values of the static friction force and ultimate displacement can be ultimately reduced to 23.1% and 50% of those without ultrasonic vibrations, respectively. (fundamental areas of phenomenology(including applications))

  11. New algorithm for controlling electric arc furnaces using their vibrational and acoustic characteristics

    Science.gov (United States)

    Cherednichenko, V. S.; Bikeev, R. A.; Serikov, V. A.; Rechkalov, A. V.; Cherednichenko, A. V.

    2016-12-01

    The processes occurring in arc discharges are analyzed as the sources of acoustic radiation in an electric arc furnace (EAF). Acoustic vibrations are shown to transform into mechanical vibrations in the furnace laboratory. The shielding of the acoustic energy fluxes onto water-cooled wall panels by a charge is experimentally studied. It is shown that the rate of charge melting and the depth of submergence of arc discharges in the slag and metal melt can be monitored by measuring the vibrational characteristics of furnaces and using them in a universal industrial process-control system, which was developed for EAFs.

  12. Vibrational Characteristics of ring-type ultrasonic motor stator using ESPI

    International Nuclear Information System (INIS)

    Jung, Hyun Kyu; Paik, Sung Hoon; Kim, Seung Ho; Park, Ki Jun; Wang, Young Sung

    2001-01-01

    A stator of ring-type ultrasonic motor composed of the piezoelectric ceramic and the elastic metal was made to generate the travelling wave. Vibrational behavior of the stator was simulated by a finite element analysis using ATILA program and was measured by the electronic speckle pattern interferometry (ESPI) method. The resonance frequencies and vibration modes were analysed depending upon the comparison between the finite element analysis and ESPI measurement. The optimal vibration mode and frequency was estimated to be 7th resonant mode which was corresponded to the measured frequency of 39 KHz. It could be concluded that this fabricated stator can be applied for ring-type ultrasonic motor.

  13. Chirality sensing of bioactive compounds with amino alcohol unit via circular dichroism.

    Science.gov (United States)

    Górecki, Marcin; Groszek, Grażyna; Frelek, Jadwiga

    2017-10-01

    The aim of the present work was to test various chiroptical techniques, including in particular the in situ dirhodium methodology, to assign the absolute configuration of 1,2- and 1,3-amino alcohols. As models, we selected mainly compounds that have both an additional strongly absorbing and interfering chromophoric system and application in medicinal chemistry. Determination of the absolute configuration (AC) of the tested molecules such as cinchona alkaloids, Tamiflu, and others was carried out using a combination of electronic and vibrational circular dichroism (ECD, VCD) spectroscopy. It has been demonstrated that both 1,2- and 1,3-aminol moieties are subject to the same sector rule correlating stereostructure of formed Rh 2 -complex with chiroptical properties, and that the changes in the position of the stereogenic center do not affect its proper use. © 2017 Wiley Periodicals, Inc.

  14. Clinical measuring system for the form and position errors of circular workpieces using optical fiber sensors

    Science.gov (United States)

    Tan, Jiubin; Qiang, Xifu; Ding, Xuemei

    1991-08-01

    Optical sensors have two notable advantages in modern precision measurement. One is that they can be used in nondestructive measurement because the sensors need not touch the surfaces of workpieces in measuring. The other one is that they can strongly resist electromagnetic interferences, vibrations, and noises, so they are suitable to be used in machining sites. But the drift of light intensity and the changing of the reflection coefficient at different measuring positions of a workpiece may have great influence on measured results. To solve the problem, a spectroscopic differential characteristic compensating method is put forward. The method can be used effectively not only in compensating the measuring errors resulted from the drift of light intensity but also in eliminating the influence to measured results caused by the changing of the reflection coefficient. Also, the article analyzes the possibility of and the means of separating data errors of a clinical measuring system for form and position errors of circular workpieces.

  15. A periodic piezoelectric smart structure with the integrated passive/active vibration-reduction performances

    Science.gov (United States)

    Wang, Yuxi; Niu, Shengkai; Hu, Yuantai

    2017-06-01

    The paper proposes a new piezoelectric smart structure with the integrated passive/active vibration-reduction performances, which is made of a series of periodic structural units. Every structural unit is made of two layers, one is an array of piezoelectric bimorphs (PBs) and one is an array of metal beams (MBs), both are connected as a whole by a metal plate. Analyses show that such a periodic smart structure possesses two aspects of vibration-reduction performance: one comes from its phonon crystal characteristics which can isolate those vibrations with the driving frequency inside the band gap(s). The other one comes from the electromechanical conversion of bent PBs, which is actively aimed at those vibrations with the driving frequency outside the band gap(s). By adjusting external inductance, the equivalent circuit of the proposed structure can be forced into parallel resonance such that most of the vibration energy is converted into electrical energy for dissipation by a resistance. Thus, an external circuit under the parallel resonance state is equivalent to a strong damping to the interrelated vibrating structure, which is just the action mechanism of the active vibration reduction performance of the proposed smart structure.

  16. DYNAMIC MODELLING OF VIBRATIONS ASSISTED DRILLING

    Directory of Open Access Journals (Sweden)

    Mathieu LADONNE

    2015-05-01

    Full Text Available The number of multi-materials staking configurations for aeronautical structures is increasing, with the evolution of composite and metallic materials. For drilling the fastening holes, the processes of Vibration Assisted Drilling (VAD expand rapidly, as it permits to improve reliability of drilling operations on multilayer structures. Among these processes of VAD, the solution with forced vibrations added to conventional feed to create a discontinuous cutting is the more developed in industry. The back and forth movement allows to improve the evacuation of chips by breaking it. This technology introduces two new operating parameters, the frequency and the amplitude of the oscillation. To optimize the process, the choice of those parameters requires first to model precisely the operation cutting and dynamics. In this paper, a kinematic modelling of the process is firstly proposed. The limits of the model are analysed through comparison between simulations and measurements. The proposed model is used to develop a cutting force model that allows foreseeing the operating conditions which ensure good chips breaking and tool life improvement.

  17. Partial admission effect on the performance and vibration of a supersonic impulse turbine

    Science.gov (United States)

    Lee, Hang Gi; Shin, Ju Hyun; Choi, Chang-Ho; Jeong, Eunhwan; Kwon, Sejin

    2018-04-01

    This study experimentally investigates the effects of partial admission on the performance and vibration outcomes of a supersonic impulse turbine with circular nozzles. The turbine of a turbopump for a gas-generator-type liquid rocket engine in the Korea Space Launch Vehicle-II is of the supersonic impulse type with the partial admission configuration for obtaining a high specific power. Partial admission turbines with a low-flow-rate working gas exhibit benefits over turbines with full admission, such as loss reduction, ease of controllability of the turbine power output, and simple turbine configurations with separate starting sections. However, the radial force of the turbine rotor due to the partial admission causes an increase in turbine vibration. Few experimental studies have previously been conducted regarding the partial admission effects on supersonic impulse turbines with circular nozzles. In the present study, performance tests of supersonic impulse turbines with circular nozzles were conducted for various partial admission ratios using a turbine test facility with high-pressure air in order to investigate the resulting aerodynamic performance and vibration. Four types of turbines with partial admission ratios of 0.17, 0.42, 0.75 and 0.83 were tested. Results show that the efficiencies at the design point increase linearly as the partial admission ratios increase. Moreover, as the velocity ratios increase, the difference in efficiency from the reference turbine with a partial admission ratio of 0.83 becomes increasingly significant, and the magnitudes of these differences are proportional to the square of the velocity ratios. Likewise, the decrease in the partial admission ratio results in an increase in the turbine vibration level owing to the increase in the radial force.

  18. In-situ Studies of the Reactions of Bifunctional and Heterocyclic Molecules over Noble Metal Single Crystal and Nanoparticle Catalysts Studied with Kinetics and Sum-Frequency Generation Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kliewer, Christopher J. [Univ. of California, Berkeley, CA (United States)

    2009-06-30

    Sum frequency generation surface vibrational spectroscopy (SFG-VS) in combination with gas chromatography (GC) was used in-situ to monitor surface bound reaction intermediates and reaction selectivities for the hydrogenation reactions of pyrrole, furan, pyridine, acrolein, crotonaldehyde, and prenal over Pt(111), Pt(100), Rh(111), and platinum nanoparticles under Torr reactant pressures and temperatures of 300K to 450K. The focus of this work is the correlation between the SFG-VS observed surface bound reaction intermediates and adsorption modes with the reaction selectivity, and how this is affected by catalyst structure and temperature. Pyrrole hydrogenation was investigated over Pt(111) and Rh(111) single crystals at Torr pressures. It was found that pyrrole adsorbs to Pt(111) perpendicularly by cleaving the N-H bond and binding through the nitrogen. However, over Rh(111) pyrrole adsorbs in a tilted geometry binding through the {pi}-aromatic orbitals. A surface-bound pyrroline reaction intermediate was detected over both surfaces with SFG-VS. It was found that the ring-cracking product butylamine is a reaction poison over both surfaces studied. Furan hydrogenation was studied over Pt(111), Pt(100), 10 nm cubic platinum nanoparticles and 1 nm platinum nanoparticles. The product distribution was observed to be highly structure sensitive and the acquired SFG-VS spectra reflected this sensitivity. Pt(100) exhibited more ring-cracking to form butanol than Pt(111), while the nanoparticles yielded higher selectivities for the partially saturated ring dihydrofuran. Pyridine hydrogenation was investigated over Pt(111) and Pt(100). The α-pyridyl surface adsorption mode was observed with SFG-VS over both surfaces. 1,4-dihydropyridine was seen as a surface intermediate over Pt(100) but not Pt(111). Upon heating the surfaces to 350K, the adsorbed pyridine changes to a flat-lying adsorption mode. No evidence was found for the pyridinium cation. The hydrogenation of the

  19. Evaluating Program about Performance of Circular Sodium Heat Pipe

    International Nuclear Information System (INIS)

    Kwak, Jae Sik; Kim, Hee Reyoung

    2014-01-01

    The superior heat transfer capability, structural simplicity, relatively inexpensive, insensitivity to the gravitational field, silence and reliability are some of its outstanding features. We study about heat transfer equation of heat pipe and program predicting performance which is considering geometrical shape of heat pipe by the related heat transfer equation of heat pipe. The operating temperature is 450 .deg. C - 950 .deg. C, working fluid is sodium, material for container is stainless steel, and type of wick is sintered metal. As a result of evaluating program about performance of circular sodium heat pipe based on MATLAB code, express correlation between radius and LHR, correlation between heat transfer length and LHR, correlation between wick and LHR, correlation between operating temperature and LHR. Generally radius values of heat pipe are proportional to LHR because of increase of mass flow which is main factor of heat flow. Heat transfer length values of heat pipe are inversely proportional to LHR and slightly inversely proportional to heat rate. Pore size is proportional to LHR. Although increase of pore size decrease capillary pressure, decrease more pressure drop in liquid phase. As a result, mass flow and heat rate are increase. But we have to do additional consideration about pore size and voidage in the aspect of safety and production technique

  20. Evaluating Program about Performance of Circular Sodium Heat Pipe

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Jae Sik; Kim, Hee Reyoung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-10-15

    The superior heat transfer capability, structural simplicity, relatively inexpensive, insensitivity to the gravitational field, silence and reliability are some of its outstanding features. We study about heat transfer equation of heat pipe and program predicting performance which is considering geometrical shape of heat pipe by the related heat transfer equation of heat pipe. The operating temperature is 450 .deg. C - 950 .deg. C, working fluid is sodium, material for container is stainless steel, and type of wick is sintered metal. As a result of evaluating program about performance of circular sodium heat pipe based on MATLAB code, express correlation between radius and LHR, correlation between heat transfer length and LHR, correlation between wick and LHR, correlation between operating temperature and LHR. Generally radius values of heat pipe are proportional to LHR because of increase of mass flow which is main factor of heat flow. Heat transfer length values of heat pipe are inversely proportional to LHR and slightly inversely proportional to heat rate. Pore size is proportional to LHR. Although increase of pore size decrease capillary pressure, decrease more pressure drop in liquid phase. As a result, mass flow and heat rate are increase. But we have to do additional consideration about pore size and voidage in the aspect of safety and production technique.