Rotational and vibrational synthetic spectra of linear parent molecules in comets

International Nuclear Information System (INIS)

Crovisier, J.

1987-01-01

We evaluate and model the excitation conditions of linear parent molecules in cometary atmospheres. The model is valid for most linear molecules without electronic angular momentum. It takes into account collisions and infrared excitation. The molecule rotational population distribution is computed as a function of distance to nucleus. The line intensities of the strongest parallel and perpendicular fundamental vibrational bands, as well as the pure rotational lines, can then be evaluated. This model is applied to several candidate parent molecules, for observing conditions corresponding to available or planned instruments, either ground-based or aboard aircrafts, satellites or space probes

Design and experimental investigation of a magnetically coupled vibration energy harvester using two inverted piezoelectric cantilever beams for rotational motion

International Nuclear Information System (INIS)

Zou, Hong-Xiang; Zhang, Wen-ming; Li, Wen-Bo; Wei, Ke-Xiang; Gao, Qiu-Hua; Peng, Zhi-Ke; Meng, Guang

2017-01-01

Highlights: • A magnetically coupled two-degree-of-freedom harvester for rotation is proposed. • The electromechanical coupling model is developed and validated experimentally. • The harvester can generate high voltage at low rotating speeds. • The harvester can harvest vibration energy in multiple frequency bands. - Abstract: Energy can be harvested from rotational motion for powering wireless autonomous electronic devices. The paper presents a magnetically coupled two-degree-of-freedom vibration energy harvester for rotary motion applications. The design consists of two inverted piezoelectric cantilever beams whose free ends point to the rotating shaft. The centrifugal force of the inverted cantilever beam is beneficial to producing large amplitude in a low speed range. The electromechanical coupling dynamical model is developed by the energy method from Hamilton’s principle and validated experimentally. The experimental results indicate that the presented harvester is suitable for low speed rotation and can harvest vibration energy in multiple frequency bands. The first and second resonant behaviors of voltage can be obtained at 420 r/min and 550 r/min, and the average output powers are 564 μW and 535.3 μW, respectively.

Rotational and High-resolution Infrared Spectrum of HC3N: Global Ro-vibrational Analysis and Improved Line Catalog for Astrophysical Observations

Science.gov (United States)

Bizzocchi, Luca; Tamassia, Filippo; Laas, Jacob; Giuliano, Barbara M.; Degli Esposti, Claudio; Dore, Luca; Melosso, Mattia; Canè, Elisabetta; Pietropolli Charmet, Andrea; Müller, Holger S. P.; Spahn, Holger; Belloche, Arnaud; Caselli, Paola; Menten, Karl M.; Garrod, Robin T.

2017-11-01

HC3N is a ubiquitous molecule in interstellar environments, from external galaxies to Galactic interstellar clouds, star-forming regions, and planetary atmospheres. Observations of its rotational and vibrational transitions provide important information on the physical and chemical structures of the above environments. We present the most complete global analysis of the spectroscopic data of HC3N. We recorded the high-resolution infrared spectrum from 450 to 1350 cm-1, a region dominated by the intense {ν }5 and {ν }6 fundamental bands, located at 660 and 500 cm-1, respectively, and their associated hot bands. Pure rotational transitions in the ground and vibrationally excited states were recorded in the millimeter and submillimeter regions in order to extend the frequency range so far considered in previous investigations. All of the transitions from the literature and from this work involving energy levels lower than 1000 cm-1 were fitted together to an effective Hamiltonian. Because of the presence of various anharmonic resonances, the Hamiltonian includes a number of interaction constants, in addition to the conventional rotational and vibrational l-type resonance terms. The data set contains about 3400 ro-vibrational lines of 13 bands and some 1500 pure rotational lines belonging to 12 vibrational states. More than 120 spectroscopic constants were determined directly from the fit, without any assumption deduced from theoretical calculations or comparisons with similar molecules. An extensive list of highly accurate rest frequencies was produced to assist astronomical searches and data interpretation. These improved data enabled a refined analysis of the ALMA observations toward Sgr B2(N2).

Systematics of the K 2·gamma vibrational bands and odd–even ...

Indian Academy of Sciences (India)

(RTR) model of Davydov et al [2] it represents an anomalous rotation band. Wilets and ... 4 2 values of 2.0 to 3.33, i.e., from the harmonic vibrator to rotor limit. Gupta et al [14] used the Mallmann plot to illustrate a smooth variation of these R. J 2 ratios as ..... For individual isotopic chains also S(4) falls with increas- ing R. 4 2.

Vibrational and Rotational Energy Relaxation in Liquids

DEFF Research Database (Denmark)

Petersen, Jakob

Vibrational and rotational energy relaxation in liquids are studied by means of computer simulations. As a precursor for studying vibrational energy relaxation of a solute molecule subsequent to the formation of a chemical bond, the validity of the classical Bersohn-Zewail model for describing......, the vibrational energy relaxation of I2 subsequent to photodissociation and recombination in CCl4 is studied using classical Molecular Dynamics simulations. The vibrational relaxation times and the time-dependent I-I pair distribution function are compared to new experimental results, and a qualitative agreement...... is found in both cases. Furthermore, the rotational energy relaxation of H2O in liquid water is studied via simulations and a power-and-work analysis. The mechanism of the energy transfer from the rotationally excited H2O molecule to its water neighbors is elucidated, i.e. the energy-accepting degrees...

A microscopic derivation of nuclear collective rotation-vibration model and its application to nuclei

Energy Technology Data Exchange (ETDEWEB)

Gulshani, P., E-mail: matlap@bell.net [NUTECH Services, 3313 Fenwick Crescent, Mississauga, Ontario, L5L 5N1 (Canada)

2016-07-07

We derive a microscopic version of the successful phenomenological hydrodynamic model of Bohr-Davydov-Faessler-Greiner for collective rotation-vibration motion of an axially symmetric deformed nucleus. The derivation is not limited to small oscillation amplitude. The nuclear Schrodinger equation is canonically transformed to collective co-ordinates, which is then linearized using a constrained variational method. The associated constraints are imposed on the wavefunction rather than on the particle co-ordinates. The approach yields three self-consistent, time-reversal invariant, cranking-type Schrodinger equations for the rotation-vibration and intrinsic motions, and a self-consistency equation. For harmonic oscillator mean-field potentials, these equations are solved in closed forms for excitation energy, cut-off angular momentum, and other nuclear properties for the ground-state rotational band in some deformed nuclei. The results are compared with measured data.

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)

METHOD FOR DETERMINATION OF ROTATION CENTER IN VIBRATING OBJECT

Directory of Open Access Journals (Sweden)

I. P. Kauryha

2016-01-01

Full Text Available Linear piezoelectric gauges, eddy current transducers and other control and measuring devices have been widely applied for vibration diagnostics of objects in industry. Methods based on such gauges and used for measuring angular and linear vibrations do not provide the possibility to assess a rotation center or point angle of an object. Parasitic oscillations may occur during rotor rotation and in some cases the oscillations are caused by dis-balance. The known methods for measuring angular and linear vibrations make it possible to detect the phenomenon and they do not provide information for balancing of the given object. For this very reason the paper describes a method for obtaining instantaneous rotation center in the vibrating object. It allows to improve informational content of the measurements owing to obtaining additional data on position of object rotation center. The obtained data can be used for balancing of a control object. Essence of the given method is shown by an example of piezoelectric gauges of linear vibrations. Two three-axial gauges are fixed to the investigated object. Then gauge output signals are recalculated in angular vibrations of the object (for this purpose it is necessary to know a distance between gauges. Further projection positions of the object rotation center are determined on three orthogonal planes. Instantaneous rotation center is calculated according to the position of one of the gauges. The proposed method permits to obtain data on linear and angular vibrations and rotation center position of the vibrating object using one system of linear gauge. Possibilities of object diagnostics are expanded due to increase in number of determined parameters pertaining to object moving. The method also makes it possible to reduce material and time expenses for measurement of an angular vibration component. 

Energy correlations for mixed rotational bands

International Nuclear Information System (INIS)

Doessing, T.

1985-01-01

A schematic model for the mixing of rotational bands above the yrast line in well deformed nuclei is considered. Many-particle configurations of a rotating mean field form basis bands, and these are subsequently mixed due to a two body residual interaction. The energy interval over which a basis band is spread out increases with increasing excitation energy above the yrast line. Conversely, the B(E2) matrix element for rotational decay out of one of the mixed band states is spread over an interval which is predicted to become more narrow with increasing excitation energy. Finally, the implication of band mixing for γ-ray energy correlations is briefly discussed. (orig.)

Vibrational motions in rotating nuclei studied by Coulomb excitations

Energy Technology Data Exchange (ETDEWEB)

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

1998-03-01

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

Evolution from vibration to rotation in 108Cd nucleus within microscopic theory

International Nuclear Information System (INIS)

Ni Shaoyong; Tong Hong; Zhao Xingzhi; Shi Zhuyi; The Secon Northwest Inst. for Minority, Yinchuan; Zhang Chunmei; Lei Yuxi

2008-01-01

Based on the microscopic sdIBM-F max model and the single-particle energies from experiment, with the use of the most general Hamiltonian, the vibrational band and rotational band in 108 Cd nucleus as well as its evolutional process were reproduced very well by two different groups of nucleon-nucleon effective interaction parameters. And phenomenological study identifies that: 1) The coexisting region of two excitation models is on the interval between the state 8+ and state 14 1 + (this is a interval with E x =3.683-5.503 MeV), and the 8 1 + state is a state preponderant in the vibrational model, the 14 1 + state is one predominant in the rotational model, while the state 10 1 + is a cross- bencher state relative to the two models; 2) The yrast states from the ground-state up to the 24 1 + state all are collective states, hereafter the first breaking up and aligning state maybe is a two-quasiparticle state of neutron on the intruder orbits h 11/2 ; 3) This structure evolution has been achieved via the moderate changes of the pair coupling probability of valence nucleons in the coexisting region, and thus is not very rapidly. (authors)

Vibrational-rotational relaxation of the simplest hydrogen-containing molecules (review)

International Nuclear Information System (INIS)

Molevich, N.E.; Oraevskii, A.N.

1987-01-01

In connection with the development of chemical lasers much attention is now devoted to the study of kinetic processes is gaseous mixtures containing the hydrogen halides. Vibrational relaxation of molecules if primarily studied without specifying its relation to the rational levels. Rotational relaxation is regarded a priori as faster than vibrational relaxation, so that the population of the rotational levels is assumed to be in equilibrium. This approach to the relaxation of hydrogen halide molecules (and other diatomic hydrogen-containing molecules), however, is unable to explain satisfactorily the results of the papers discussed below. An analysis of the data obtained in these papers leads to the conclusion that the general picture of relaxation in diatomic hydrogen-containing molecules must be viewed as a unified process of vibrational and rotational relaxation. It is shown that those effects observed during vibrational relaxation of such molecules which are unusual from the standpoint of the theory of vibrational-translational relaxation are well explained in terms of intermolecular vibrational-rotational relaxation together with pure rotational relaxation

A multitude of rotational bands in {sup 163}Er and their mutual interaction

Energy Technology Data Exchange (ETDEWEB)

Bosetti, P.; Leoni, S.; Bracco, A. [Univ. of Milan (Italy)] [and others

1996-12-31

Using the {sup 150}Nd({sup 18}O, 5n){sup 163}Er reaction a multitude of rotational bands have been established with firm spin and parity assignments in {sup 163}Er. In 16 out of {approximately} 23 band crossings E2 cross-band transitions have been observed. The interaction strength varies between {approximately} 1 and {approximately} 50 keV. These interactions sample a variety of the lowest (multi)-quasiparticle configurations. Some of the band configurations, in particular those with high K-values, can be rather well established. Quite complicated changes in the wavefunctions must occur at these crossings, and, to explain the observed interaction strengths, one may have to invoke coupling to various vibrational degrees of freedom, in addition to possible residual neutron-proton interactions.

Piezoelectric Vibration Damping Study for Rotating Composite Fan Blades

Science.gov (United States)

Min, James B.; Duffy, Kirsten P.; Choi, Benjamin B.; Provenza, Andrew J.; Kray, Nicholas

2012-01-01

Resonant vibrations of aircraft engine blades cause blade fatigue problems in engines, which can lead to thicker and aerodynamically lower performing blade designs, increasing engine weight, fuel burn, and maintenance costs. In order to mitigate undesirable blade vibration levels, active piezoelectric vibration control has been investigated, potentially enabling thinner blade designs for higher performing blades and minimizing blade fatigue problems. While the piezoelectric damping idea has been investigated by other researchers over the years, very little study has been done including rotational effects. The present study attempts to fill this void. The particular objectives of this study were: (a) to develop and analyze a multiphysics piezoelectric finite element composite blade model for harmonic forced vibration response analysis coupled with a tuned RLC circuit for rotating engine blade conditions, (b) to validate a numerical model with experimental test data, and (c) to achieve a cost-effective numerical modeling capability which enables simulation of rotating blades within the NASA Glenn Research Center (GRC) Dynamic Spin Rig Facility. A numerical and experimental study for rotating piezoelectric composite subscale fan blades was performed. It was also proved that the proposed numerical method is feasible and effective when applied to the rotating blade base excitation model. The experimental test and multiphysics finite element modeling technique described in this paper show that piezoelectric vibration damping can significantly reduce vibrations of aircraft engine composite fan blades.

Efficient forced vibration reanalysis method for rotating electric machines

Science.gov (United States)

Saito, Akira; Suzuki, Hiromitsu; Kuroishi, Masakatsu; Nakai, Hideo

2015-01-01

Rotating electric machines are subject to forced vibration by magnetic force excitation with wide-band frequency spectrum that are dependent on the operating conditions. Therefore, when designing the electric machines, it is inevitable to compute the vibration response of the machines at various operating conditions efficiently and accurately. This paper presents an efficient frequency-domain vibration analysis method for the electric machines. The method enables the efficient re-analysis of the vibration response of electric machines at various operating conditions without the necessity to re-compute the harmonic response by finite element analyses. Theoretical background of the proposed method is provided, which is based on the modal reduction of the magnetic force excitation by a set of amplitude-modulated standing-waves. The method is applied to the forced response vibration of the interior permanent magnet motor at a fixed operating condition. The results computed by the proposed method agree very well with those computed by the conventional harmonic response analysis by the FEA. The proposed method is then applied to the spin-up test condition to demonstrate its applicability to various operating conditions. It is observed that the proposed method can successfully be applied to the spin-up test conditions, and the measured dominant frequency peaks in the frequency response can be well captured by the proposed approach.

The influence of molecular rotation on vibration--translation energy transfer

International Nuclear Information System (INIS)

McKenzie, R.L.

1977-01-01

The role of molecular rotations in the exchange of vibrational and translational energy is investigated for collisions between anharmonic diatomic molecules and structureless atoms. A three-dimensional, semiclassical, impact parameter description is applied with emphasis directed towards the influence of rotational coupling on the net rate of vibrational energy transfer summed over all final rotational states. These results are then related to the predictions of an equivalent collinear collision model, and their comparison allows an evaluation of the collinear approximation. The mechanisms of vibrational energy transfer including rotational transitions are shown to be separable into three classes, with the molecules belonging to each class identified first and foremost by their ratio of fundamental vibrational and rotational frequencies, ω/sub e//B/sub e/, and second by the proximity of their initial state to a near-resonant vibration--rotation transition with a small change in angular momentum. While the dynamics of molecules with ω/sub e//B/sub e/ ratios that are comparable to the range of angular momentum transitions having strong coupling are found to require a complete three-dimensional description, the rates of vibrational energy transfer in molecules with large ω/sub e//B/sub e/ ratios appear to be well approximated by a collinear collision model

Study of rotational band in 111Sn

International Nuclear Information System (INIS)

Ganguly, S.; Banerjee, P.; Ray, I.; Kshetri, R.; Raut, R.; Goswami, A.; Saha Sarkar, M.; Bhattacharya, S.; Mukherjee, A.; Mukherjee, G.; Basu, S.K.; Mukhopadhyay, S.

2006-01-01

The motivation of the present work is to study the negative-parity rotational band in 111 Sn. Study of the lifetimes of the states of the rotational band is expected to provide information on their structures as well as the band termination phenomenon

A Computer Assisted Procedure of Assignments of Vibration-Rotation Bands of Asymmetric and Symmetric Top Molecules

Czech Academy of Sciences Publication Activity Database

Urban, Štěpán; Behrend, J.; Pracna, Petr

2004-01-01

Roč. 690, - (2004), s. 105-114 ISSN 0022-2860 R&D Projects: GA MŠk ME 445; GA ČR GA203/01/1274 Institutional research plan: CEZ:AV0Z4040901 Keywords : assigments of vibration-rotation spectra * combination differences * Loomis-Wood algorithm Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.200, year: 2004

Vibration analysis for trending ageing in rotating machinery

International Nuclear Information System (INIS)

Sinha, S.K.; Rama Rao, A.

2006-01-01

The need for condition monitoring system for important equipment and machinery is a growing requirement in every industry and more so in the nuclear power plants because of stringent safety requirements. This is largely because of the inherent benefit of being able to promote predictive maintenance practice rather than uneconomical preventive maintenance practice in the plant. Forerunner among the condition monitoring parameter is vibration signatures measured on a rotating machine. It is known that every moving element in a rotating machine generates vibration signal that is uniquely its own. Detection of such signals and monitoring the changing conditions in a machine through vibration analysis is a technique involving the knowledge of engineering art and the mathematical theory. This blend of sound engineering judgement and vibration data interpretation skill is in fact the basis of vibration diagnostic techniques. (author)

Construction of a Vibration Monitoring System for HANARO's Rotating Machinery and Analysis of Pump Vibration Signals

International Nuclear Information System (INIS)

Ryu, Jeong Soo; Yoon, Doo Byung

2005-01-01

HANARO is an open-tank-in-pool type research reactor with a thermal power of 30MW. In order to remove the heat generated by the reactor core and the reflector vessel, primary cooling pumps and reflector cooling pumps circulate coolant. These pumps are installed at the RCI(Reactor Concrete Island) which is covered by heavy concrete hatches. For the prevention of an abnormal operation of these pumps in the RCI, it is necessary to construct a vibration monitoring system that provides an alarm signal to the reactor control room when the rotating speed or the vibration level exceeds the allowable limit. The first objective of this work is to construct a vibration monitoring system for HANARO's rotating machinery. The second objective is to verify the possibility of condition monitoring of the rotating machinery. To construct a vibration monitoring system, as a first step, the standards and references related to the vibration monitoring system were investigated. In addition, to determine the number and the location of sensors that can effectively characterize the overall vibration of a pump, the vibration of the primary cooling pumps and the reflector cooling pumps were measured. Based on these results, detailed construction plans for the vibration monitoring system for HANARO were established. Then, in accordance with the construction plans, the vibration monitoring system for HANARO's rotating machinery was manufactured and installed at HANARO. To achieve the second objective, FFT analysis and bearing fault detection of the measured vibration signals were performed. The analysis results demonstrate that the accelerometers mounted at the bearing locations of the pumps can effectively monitor the pump condition

Validity of single term energy expression for ground state rotational band of even-even nuclei

International Nuclear Information System (INIS)

Sharma, S.; Kumar, R.; Gupta, J.B.

2005-01-01

Full text: There are large numbers of empirical studies of gs band of even-even nuclei in various mass regions. The Bohr-Mottelson's energy expression is E(I) = AX + BX 2 +CX 3 +... where X = I(I+1). The anharmonic vibrator energy expression is: E(I) = al + bl 2 + cl 3 SF model with energy expression: E(I)= pX + qI + rXI... where the terms represents the rotational, vibrational and R-V interaction energy, respectively. The validity f the various energy expressions with two terms had been tested by Sharma for light, medium and heavy mass regions using R I s. R 4 plots (where, spin I=6, 8, 10, 12), which are parameter independent. It was also noted, that of the goodness of energy expression can be judged with the minimum input of energies (i.e. only 2 parameters) and predictability's of the model p to high spins. Recently, Gupta et. al proposed a single term energy expression (SSTE) which was applied for rare earth region. This proposed power law reflected the unity of rotation - vibration in a different way and was successful in explaining the structure of gs-band. It will be useful for test the single term energy expression for light and heavy mass region. The single term expression for energy of ground state band can be written as: E I =axI b , where the index b and the coefficient a are the constant for the band. The values of b+1 and a 1 are as follows: b 1 =log(R 1 )/log(I/2) and a 1 =E I /I b ... The following results were gained: 1) The sharp variation in the value of index b at given spin will be an indication of the change in the shape of the nucleus; 2) The value of E I /I b is fairly constant with spin below back-bending, which reflects the stability of shape with spin; 3) This proposed power law is successful in explaining the structure of gs-band of nuclei

Triaxial energy relation to describe rotational band in 98-112Ru nuclei

International Nuclear Information System (INIS)

Singh, Yuvraj; Gupta, K.K.; Bihari, Chhail; Varshney, A.K.; Varshney, Mani; Singh, M.; Gupta, D.K.

2010-01-01

In a broader perspective rotation vibration coupling parameter (b) is considered changing with the change in excitation energy (ε 1 ) and is evaluated on fitting experimental energy for 98-112 Ru isotopes in the frame work of general asymmetric rotor model. The moment of inertia parameter (a), common to yrast and quasi-γ band, is calculated from deformation parameter (β) using general empirical relation. The present work is undertaken to suggest some suitable equation for the trajectories which are similar in shape in 98-112 Ru nuclei

Rotational-vibrational states of nonaxial deformable even-even nuclei

International Nuclear Information System (INIS)

Porodzinskii, Yu.V.; Sukhovitskii, E.Sh.

1991-01-01

The rotational-vibrational excitations of nonaxial even-even nuclei are studied on the basis of a Hamiltonian operator with five dynamical variables. Explicit forms of the wave functions and energies of the rotational-vibrational excitations of such nuclei are obtained. The experimental energies of excited positive-parity states of the 238 U nucleus and those calculated in terms of the model discussed in the article are compared

On selection rules in vibrational and rotational molecular spectroscopy

International Nuclear Information System (INIS)

Guichardet, A.

1986-01-01

The aim of this work is a rigorous proof of the Selection Rules in Molecular Spectroscopy (Vibration and Rotation). To get this we give mathematically rigorous definitions of the (tensor) transition operators, in this case the electric dipole moment; this is done, firstly by considering the molecule as a set of point atomic kernels performing arbitrary motions, secondly by limiting ourselves either to infinitesimal vibration motions, or to arbitrary rotation motions. Then the selection rules follow from an abstract formulation of the Wigner-Eckart theorem. In a last paragraph we discuss the problem of separating vibration and rotation motions; very simple ideas from Differential Geometry, linked with the ''slice theorem'', allow us to define the relative speeds, the solid motions speeds, the Coriolis energies and the moving Eckart frames [fr

Laser diagnostics of high vibrational and rotational H2-states

International Nuclear Information System (INIS)

Mosbach, Th.; Schulz-von der Gathen, V.; Doebele, H.F.

2002-01-01

We report on measurements of vibrational and rotational excited electronic-ground-state hydrogen molecules in a magnetic multipole plasma source by LIF with VUV radiation. The measurements are taken after rapid shut-off of the discharge current. Absolute level populations are obtained using Rayleigh scattering calibration with Krypton. The theoretically predicted suprathermal population of the vibrational distribution is clearly identified. We found also non-Boltzmann rotational distributions for the high vibrational states. The addition of noble gases (Argon and Xenon) to hydrogen leads to a decrease of the vibrational population. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

A Study on the Vibration Measurement and Analysis of Rotating Machine Foundations

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Rim; Jeon, Kyu Sik; Suh, Young Pyo; Cho, Chul Hwan; Kim, Sung Taeg; Lee, Myung Kyu [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

1996-12-31

To search for the cause of vibration problem of rotating machine in the power plant, first the rotating machine is classified according to their type and each vibration characteristic is reviewed. The criteria for the evaluation of mechanical vibration effect on the structure and human being during the design of machine foundation is described below. The foundation of rotating machine is classified according to its shape and some factors are described which should be considered during dynamic modeling analysis for its correct result. Also the methods of incorporating foundation vibration into mechanical vibration analysis are reviewed. Type of vibration measurement and analysis which is used to find out the dynamic characteristic of structure is described in accordance with its signal processing and measuring method. Measurement of vibration and its analysis when there occurs real vibration troubles in power plant are compared with the results of numerical modeling as case studies. (author). 16 refs., 23 figs.

Complete flexural vibration band gaps in membrane-like lattice structures

International Nuclear Information System (INIS)

Yu Dianlong; Liu Yaozong; Qiu Jing; Wang Gang; Zhao Honggang

2006-01-01

The propagation of flexural vibration in the periodical membrane-like lattice structure is studied. The band structure calculated with the plane wave expansion method indicates the existence of complete gaps. The frequency response function of a finite periodic structure is simulated with finite element method. Frequency ranges with vibration attenuation are in good agreement with the gaps found in the band structure. Much larger attenuations are found in the complete gaps comparing to those directional ones. The existence of complete flexural vibration gaps in such a lattice structure provides a new idea for vibration control of thin plates

Eckart frame vibration-rotation Hamiltonians: Contravariant metric tensor

International Nuclear Information System (INIS)

Pesonen, Janne

2014-01-01

Eckart frame is a unique embedding in the theory of molecular vibrations and rotations. It is defined by the condition that the Coriolis coupling of the reference structure of the molecule is zero for every choice of the shape coordinates. It is far from trivial to set up Eckart kinetic energy operators (KEOs), when the shape of the molecule is described by curvilinear coordinates. In order to obtain the KEO, one needs to set up the corresponding contravariant metric tensor. Here, I derive explicitly the Eckart frame rotational measuring vectors. Their inner products with themselves give the rotational elements, and their inner products with the vibrational measuring vectors (which, in the absence of constraints, are the mass-weighted gradients of the shape coordinates) give the Coriolis elements of the contravariant metric tensor. The vibrational elements are given as the inner products of the vibrational measuring vectors with themselves, and these elements do not depend on the choice of the body-frame. The present approach has the advantage that it does not depend on any particular choice of the shape coordinates, but it can be used in conjunction with all shape coordinates. Furthermore, it does not involve evaluation of covariant metric tensors, chain rules of derivation, or numerical differentiation, and it can be easily modified if there are constraints on the shape of the molecule. Both the planar and non-planar reference structures are accounted for. The present method is particular suitable for numerical work. Its computational implementation is outlined in an example, where I discuss how to evaluate vibration-rotation energies and eigenfunctions of a general N-atomic molecule, the shape of which is described by a set of local polyspherical coordinates

Pair correlation of super-deformed rotation band

International Nuclear Information System (INIS)

Shimizu, Yoshio

1989-01-01

The effect of pair correlation, one of the most important residual interactions associated with the super-deformed rotation band, is discussed in terms of the characteristics of the rotation band (its effect on the moment of inertia in particular), and the tunneling into an normal deformed state in relation to its effect on the angular momentum dependence of the potential energy plane as a function of the deformation. The characteristics of the rotation band is discussed in terms of the kinematic and dynamic momenta of inertia. It is shown that the pair correlation in a super-deformed rotation band acts to decrease the former and increase the latter momentum mainly due to dynamic pair correlation. A theoretical approach that takes this effect into account can provide results that are consistent with measured momenta, although large differences can occur in some cases. Major conflicts include a large measured kinetic momentum of inertia compared to the theoretical value, and the absence of the abnormality (shape increase) generally seen in low-spin experiments. The former seems likely to be associated with the method of measuring the angular momentum. (N.K.)

Vibrational Suspension of Light Sphere in a Tilted Rotating Cylinder with Liquid

Directory of Open Access Journals (Sweden)

Victor G. Kozlov

2014-01-01

Full Text Available The dynamics of a light sphere in a quickly rotating inclined cylinder filled with liquid under transversal vibrations is experimentally investigated. Due to inertial oscillations of the sphere relative to the cavity, its rotation velocity differs from the cavity one. The intensification of the lagging motion of a sphere and the excitation of the outstripping differential rotation are possible under vibrations. It occurs in the resonant areas where the frequency of vibrations coincides with the fundamental frequency of the system. The position of the sphere in the center of the cylinder could be unstable. Different velocities of the sphere are matched with its various quasistationary positions on the axis of rotating cavity. In tilted rotating cylinder, the axial component of the gravity force appears; however, the light sphere does not float to the upper end wall but gets the stable position at a definite distance from it. It makes possible to provide a vibrational suspension of the light sphere in filled with liquid cavity rotating around the vertical axis. It is found that in the wide range of the cavity inclination angles the sphere position is determined by the dimensionless velocity of body differential rotation.

An expert system for vibration based diagnostics of rotating machines

International Nuclear Information System (INIS)

Korteniemi, A.

1990-01-01

Very often changes in the mechanical condition of the rotating machinery can be observed as changes in its vibration. This paper presents an expert system for vibration-based diagnosis of rotating machines by describing the architecture of the developed prototype system. The importance of modelling the problem solving knowledge as well as the domain knowledge is emphasized by presenting the knowledge in several levels

Characteristics of steady vibration in a rotating hub-beam system

Science.gov (United States)

Zhao, Zhen; Liu, Caishan; Ma, Wei

2016-02-01

A rotating beam features a puzzling character in which its frequencies and modal shapes may vary with the hub's inertia and its rotating speed. To highlight the essential nature behind the vibration phenomena, we analyze the steady vibration of a rotating Euler-Bernoulli beam with a quasi-steady-state stretch. Newton's law is used to derive the equations governing the beam's elastic motion and the hub's rotation. A combination of these equations results in a nonlinear partial differential equation (PDE) that fully reflects the mutual interaction between the two kinds of motion. Via the Fourier series expansion within a finite interval of time, we reduce the PDE into an infinite system of a nonlinear ordinary differential equation (ODE) in spatial domain. We further nondimensionalize the ODE and discretize it via a difference method. The frequencies and modal shapes of a general rotating beam are then determined numerically. For a low-speed beam where the ignorance of geometric stiffening is feasible, the beam's vibration characteristics are solved analytically. We validate our numerical method and the analytical solutions by comparing with either the past experiments or the past numerical findings reported in existing literature. Finally, systematic simulations are performed to demonstrate how the beam's eigenfrequencies vary with the hub's inertia and rotating speed.

Identical high- K three-quasiparticle rotational bands

Energy Technology Data Exchange (ETDEWEB)

Kaur, Harjeet; Singh, Pardeep [Guru Nanak Dev University, Department of Physics, Amritsar (India)

2016-12-15

A comprehensive study of high-K three-quasiparticle rotational bands in odd-A nuclei indicates the similarity in γ-ray energies and dynamic moment of inertia I{sup (2)}. The extent of the identicality between the rotational bands is evaluated by using the energy factor method. For nuclei pairs exhibiting identical bands, the average relative change in the dynamic moment of inertia I{sup (2)} is also determined. The identical behaviour shown by these bands is attributed to the interplay of nuclear structure parameters: deformation and the pairing correlations. Also, experimental trend of the I(ℎ) vs. ℎω (MeV) plot for these nuclei pairs is shown to be in agreement with Tilted-Axis Cranking (TAC) model calculations. (orig.)

Group-theoretical and topological analysis of localized rotation-vibration states

International Nuclear Information System (INIS)

Sadovskii, D.A.; Zhilinskii, B.I.

1993-01-01

A general scheme of qualitative analysis is applied to molecular rovibrational problems. The classical-quantum correspondence provides a description of different classes of localized quantum rotation-vibration states associated with localized classical motion. A description of qualitative features, such as localized motion, and of qualitative changes, such as localization phenomena, is based on the concept of the simplest Hamiltonian. It uses only the topological properties of the compact reduced phase space and the action of the symmetry group on this space. The qualitative changes of the simplest Hamiltonian are analyzed as bifurcations caused by rotational or vibrational excitation. The relation between the stationary points of the classical Hamiltonian function on the reduced phase space and the principal periodic trajectories in the coordinate space is analyzed for vibrational Hamiltonians. In particular, the relation between the nonlinear normal modes, proposed by Montaldi, Roberts, and Stewart [Philos. Trans. R. Soc. London, Ser. A 325, 237 (1988)], and normal- and local-mode models widely used in molecular physics is discussed. Along with a general consideration of localized rotational and vibrational states a more detailed analysis of the vibrational dynamics of an X 3 molecule with the D 3h symmetry, such as the H 3 + molecular ion, is given

Identical gamma-vibrational bands in {sup 165}Ho

Energy Technology Data Exchange (ETDEWEB)

Radford, D.C.; Galindo-Uribarri, A.; Janzen, V.P. [Chalk River Labs., Ontario (Canada)] [and others

1996-12-31

The structure of {sup 165}Ho at moderate spins has been investigated by means of Coulomb excitation. Two {gamma}-vibrational bands (K{sup {pi}} = 11/2{sup {minus}} and K{sup {pi}} = 3/2{sup {minus}}) are observed, with very nearly identical in-band {gamma}-ray energies. Gamma-ray branching ratios are analyzed to extract information on Coriolis mixing, and the role of the K quantum number in identical bands is discussed.

Simultaneous rotational and vibrational CARS generation through a multiple-frequency combination technique

International Nuclear Information System (INIS)

Alden, M.; Bengtsson, P.E.; Edner, H.

1987-01-01

One most promising laser technique for probing combustion processes is coherent anti-Stokes Raman scattering (CARS), which due to its coherent nature and signal strength is applied in several real-world applications. Until today almost all CARS experiments are based on probing the population of molecular vibrational energy levels. However, there are several reasons rotational CARS, i.e. probing of rotational energy levels, may provide a complement to or even a better choice than vibrational CARS. Recently an alternative way to produce rotational CARS spectra is proposed, which is based on a multiple-frequency combination technique. The energy-level diagram for this process is presented. Two dye laser beams at ω/sub r/, and one fix frequency laser beam at ω/sub g/ are employed. ω/sub r,1/ and ω/sub r,2/ are two frequencies of many possible pairs with a frequency difference matching a rotational transition in a molecule. The excitation induced by ω/sub r,1/ and ω/sub r,2/ is then scattered by the narrowband ω/sub g/ beam resulting in a CARS beam ω/sub g/ at ω/sub g/ + ω/sub r,1/ - ω/sub r,2/. An interesting feature with this technique is that it is possible to generate simultaneously a rotational and vibrational CARS spectrum by using a double-folded boxcars phase matching approach. The authors believe that the proposed technique for producing rotational and vibration CARS spectra could be of interest, e.g., when measuring in highly turbulent flows. In this case the rotational CARS spectra could use for temperature measurements in the cooler parts, whereas vibrational CARS are to be preferred when measuring in the hotter parts

Rapid vibrational and rotational energy-transfer rates in heated carbon dioxide collisions by double-resonance laser spectroscopy

International Nuclear Information System (INIS)

Thomason, M.D.

1982-07-01

Rates for resonant vibrational and rotational energy transfer from the 001 state by CO 2 + CO 2 collisions have been measured. All data were obtained by double resonance spectroscopy with CO 2 lasers in a 2.5 meter absorption cell at 700 0 K. Results for rotation transfer include pumped-level relaxation and the response of other 001 levels with ΔJ up to 18. These data are compared to four relevant collision models via a 35-level rate equation analysis. Sequence-band (002 → 101) and hot-band (011 → 110) lasting have been used to observe resonant nu 3 -transfer relaxation involving 001 + 001 reversible 002 + 000, 001 + 100 reversible 101 + 000, and 001 + 010 reversible 011 + 000. A multilevel rate analysis has been utilized to determine the rate coefficients for 001 going to the 002, the 101, and the 011 levels. Part of the hot-band data has been interpreted as due to 110 + 000 reversible 100 + 010, and the associated rate constant has been estimated. The results of the study are compared to the theory and to other experiments

Vibrational-rotational model of odd-odd nuclei

International Nuclear Information System (INIS)

Afanas'ev, A.V.; Guseva, T.V.; Tamberg, Yu.Ya.

1988-01-01

The rotational vibrational (RV) model of odd nuclei is generalized to odd-odd nuclei. The hamiltonian, wave functions and matrix elements of the RV-model of odd-odd nuclei are obtained. The expressions obtained for matrix elements of the RV-model of odd-odd nuclei can be used to study the role of vibrational additions in low-lying two-particle states of odd-odd deformed nuclei. Such calculations permit to study more correctly the residual neutron-proton interaction of valent nucleons with respect to collectivization effects

Spins of superdeformed rotational bands in Tl isotopes

Energy Technology Data Exchange (ETDEWEB)

Dadwal, Anshul; Mittal, H.M. [Dr. B.R. Ambedkar National Institute of Technology, Jalandhar (India)

2017-01-15

The two-parameter model defined for even-even nuclei viz. soft-rotor formula is used to assign the band-head spin of the 17 rotational bands in Tl isotopes. The least-squares fitting method is employed to obtain the spins of these bands in the A ∝ 190 mass region. The calculated transition energies are found to depend sensitively on the proposed spin. Whenever a correct spin assignment is made, the calculated and experimental transition energies coincide very well. The dynamic moment of inertia is also calculated and its variation with rotational frequency is explored. (orig.)

α+12C rotational bands in 16O

Directory of Open Access Journals (Sweden)

Katsuma M.

2014-03-01

Full Text Available The total quantum number N of the α+12C rotational bands in 16O is determined by a study of α+12C elastic scattering. The 8+ and 9− states are found around the excitation energy Ex = 30 MeV and they are the member of the known rotational bands. At the same time, the 02+ state (Ex = 6.05 MeV is found to be dominated by N = 8.

Rotation and rotation-vibration spectroscopy of the 0+-0- inversion doublet in deuterated cyanamide.

Science.gov (United States)

Kisiel, Zbigniew; Kraśnicki, Adam; Jabs, Wolfgang; Herbst, Eric; Winnewisser, Brenda P; Winnewisser, Manfred

2013-10-03

The pure rotation spectrum of deuterated cyanamide was recorded at frequencies from 118 to 649 GHz, which was complemented by measurement of its high-resolution rotation-vibration spectrum at 8-350 cm(-1). For D2NCN the analysis revealed considerable perturbations between the lowest Ka rotational energy levels in the 0(+) and 0(-) substates of the lowest inversion doublet. The final data set for D2NCN exceeded 3000 measured transitions and was successfully fitted with a Hamiltonian accounting for the 0(+) ↔ 0(-) coupling. A smaller data set, consisting only of pure rotation and rotation-vibration lines observed with microwave techniques was obtained for HDNCN, and additional transitions of this type were also measured for H2NCN. The spectroscopic data for all three isotopic species were fitted with a unified, robust Hamiltonian allowing confident prediction of spectra well into the terahertz frequency region, which is of interest to contemporary radioastronomy. The isotopic dependence of the determined inversion splitting, ΔE = 16.4964789(8), 32.089173(3), and 49.567770(6) cm(-1), for D2NCN, HDNCN, and H2NCN, respectively, is found to be in good agreement with estimates from a simple reduced quartic-quadratic double minimum potential.

Analytic vibration-rotational matrix elements for diatomic molecules

International Nuclear Information System (INIS)

Bouanich, J.P.

1987-01-01

The vibration-rotational matrix elements for infrared or Raman transitions vJ → v'J' of diatomic molecules are calculated for powers of the reduced displacement X from parameters of the Dunham potential-energy function. (orig.)

Role of initial vibrational and rotational

Indian Academy of Sciences (India)

To investigate the effects of reagent vibrational and rotational states on the stereodynamical pro- ... Han et al.8 reported the total reaction cross-section, the ... ity k is contained in the xz plane, while the y-axis ...... Han B R, Yang H, Zheng Y J and Varandas A J C 2010 ... Zhang L, Chen M D, Wang M L and Han K L 2000 J.

Identicity in high-K three quasiparticle rotational bands: a theoretical approach

International Nuclear Information System (INIS)

Kaur, Harjeet; Singh, Pardeep; Malik, Sham S

2015-01-01

The systematics are studied for the identical band phenomenon in high-K three quasiparticle rotational bands. The identical rotational bands based on the same bandhead spin are analyzed on the basis of similarities in γ-ray energies, dynamic moment of inertia and kinematic moment of inertia in particular, which is a function of deformation degrees of freedom, pairing strengths and Nilsson orbitals in nuclei. It is established that a combined effect of all these parameters decides the identicity of the moment of inertia in high-K three quasiparticle rotational bands as the systematics are backed by the Tilted Axis Cranking model calculations. (paper)

Experimental Evaluation of Cold-Sprayed Copper Rotating Bands for Large-Caliber Projectiles

Science.gov (United States)

2015-05-01

process parameters used during the initial deposition of copper material, given the observation that these initial copper rotating bands tended to “ flake ...ARL-TR-7299 ● MAY 2015 US Army Research Laboratory Experimental Evaluation of Cold-Sprayed Copper Rotating Bands for Large...Experimental Evaluation of Cold-Sprayed Copper Rotating Bands for Large-Caliber Projectiles by Michael A Minnicino Weapons and Materials Research

Three-dimensional analytic probabilities of coupled vibrational-rotational-translational energy transfer for DSMC modeling of nonequilibrium flows

International Nuclear Information System (INIS)

Adamovich, Igor V.

2014-01-01

A three-dimensional, nonperturbative, semiclassical analytic model of vibrational energy transfer in collisions between a rotating diatomic molecule and an atom, and between two rotating diatomic molecules (Forced Harmonic Oscillator–Free Rotation model) has been extended to incorporate rotational relaxation and coupling between vibrational, translational, and rotational energy transfer. The model is based on analysis of semiclassical trajectories of rotating molecules interacting by a repulsive exponential atom-to-atom potential. The model predictions are compared with the results of three-dimensional close-coupled semiclassical trajectory calculations using the same potential energy surface. The comparison demonstrates good agreement between analytic and numerical probabilities of rotational and vibrational energy transfer processes, over a wide range of total collision energies, rotational energies, and impact parameter. The model predicts probabilities of single-quantum and multi-quantum vibrational-rotational transitions and is applicable up to very high collision energies and quantum numbers. Closed-form analytic expressions for these transition probabilities lend themselves to straightforward incorporation into DSMC nonequilibrium flow codes

Vibration Feature Extraction and Analysis for Fault Diagnosis of Rotating Machinery-A Literature Survey

Directory of Open Access Journals (Sweden)

Saleem Riaz

2017-02-01

Full Text Available Safety, reliability, efficiency and performance of rotating machinery in all industrial applications are the main concerns. Rotating machines are widely used in various industrial applications. Condition monitoring and fault diagnosis of rotating machinery faults are very important and often complex and labor-intensive. Feature extraction techniques play a vital role for a reliable, effective and efficient feature extraction for the diagnosis of rotating machinery. Therefore, developing effective bearing fault diagnostic method using different fault features at different steps becomes more attractive. Bearings are widely used in medical applications, food processing industries, semi-conductor industries, paper making industries and aircraft components. This paper review has demonstrated that the latest reviews applied to rotating machinery on the available a variety of vibration feature extraction. Generally literature is classified into two main groups: frequency domain, time frequency analysis. However, fault detection and diagnosis of rotating machine vibration signal processing methods to present their own limitations. In practice, most healthy ingredients faulty vibration signal from background noise and mechanical vibration signals are buried. This paper also reviews that how the advanced signal processing methods, empirical mode decomposition and interference cancellation algorithm has been investigated and developed. The condition for rotating machines based rehabilitation, prevent failures increase the availability and reduce the cost of maintenance is becoming necessary too. Rotating machine fault detection and diagnostics in developing algorithms signal processing based on a key problem is the fault feature extraction or quantification. Currently, vibration signal, fault detection and diagnosis of rotating machinery based techniques most widely used techniques. Furthermore, the researchers are widely interested to make automatic

Structural Characteristics of Rotate Vector Reducer Free Vibration

Directory of Open Access Journals (Sweden)

Chuan Chen

2017-01-01

Full Text Available For RV reducer widely used in robots, vibration significantly affects its performance. A lumped parameter model is developed to investigate free vibration characteristics without and with gyroscopic effects. The dynamic model considers key factors affecting vibration such as involute and cycloid gear mesh stiffness, crankshaft bending stiffness, and bearing stiffness. For both nongyroscopic and gyroscopic systems, free vibrations are examined and compared with each other. Results reveal the specific structure of vibration modes for both systems, which results from symmetry structure of RV reducer. According to vibration of the central components, vibration modes of two systems can be classified into three types, rotational, translational, and planetary component modes. Different from nongyroscopic system, the eigenvalues with gyroscopic effects are complex-valued and speed-dependent. The eigenvalue for a range of carrier speeds is obtained by numerical simulation. Divergence and flutter instability is observed at speeds adjacent to critical speeds. Furthermore, the work studies effects of key factors, which include crankshaft eccentricity and the number of pins, on eigenvalues. Finally, experiment is performed to verify the effectiveness of the dynamic model. The research of this paper is helpful for the analysis on free vibration and dynamic design of RV reducer.

Vibration of imperfect rotating disk

Directory of Open Access Journals (Sweden)

Půst L.

2011-12-01

Full Text Available This study is concerned with the theoretical and numerical calculations of the flexural vibrations of a bladed disk. The main focus of this study is to elaborate the basic background for diagnostic and identification methods for ascertaining the main properties of the real structure or an experimental model of turbine disks. The reduction of undesirable vibrations of blades is proposed by using damping heads, which on the experimental model of turbine disk are applied only on a limited number of blades. This partial setting of damping heads introduces imperfection in mass, stiffness and damping distribution on the periphery and leads to more complicated dynamic properties than those of a perfect disk. Calculation of FEM model and analytic—numerical solution of disk behaviour in the limited (two modes frequency range shows the splitting of resonance with an increasing speed of disk rotation. The spectrum of resonance is twice denser than that of a perfect disk.

PGOPHER: A program for simulating rotational, vibrational and electronic spectra

International Nuclear Information System (INIS)

Western, Colin M.

2017-01-01

The PGOPHER program is a general purpose program for simulating and fitting molecular spectra, particularly the rotational structure. The current version can handle linear molecules, symmetric tops and asymmetric tops and many possible transitions, both allowed and forbidden, including multiphoton and Raman spectra in addition to the common electric dipole absorptions. Many different interactions can be included in the calculation, including those arising from electron and nuclear spin, and external electric and magnetic fields. Multiple states and interactions between them can also be accounted for, limited only by available memory. Fitting of experimental data can be to line positions (in many common formats), intensities or band contours and the parameters determined can be level populations as well as rotational constants. PGOPHER is provided with a powerful and flexible graphical user interface to simplify many of the tasks required in simulating, understanding and fitting molecular spectra, including Fortrat diagrams and energy level plots in addition to overlaying experimental and simulated spectra. The program is open source, and can be compiled with open source tools. This paper provides a formal description of the operation of version 9.1. - Highlights: • Easy-to-use graphical interface for assigning and understanding molecular spectra. • Simulates rotational and vibrational structure of many types of molecular spectra. • Fits molecular properties to line positions or spectral contours. • Handles linear molecules and symmetric and asymmetric tops. • Handles perturbations, nuclear and electron spin, and electric and magnetic fields.

Signature effects in 2-qp rotational bands

International Nuclear Information System (INIS)

Jain, A.K.; Goel, A.

1992-01-01

The authors briefly review the progress in understanding the 2-qp rotational bands in odd-odd nuclei. Signature effects and the phenomenon of signature inversion are discussed. The Coriolis coupling appears to have all the ingredients to explain the inversion. Some recent work on signature dependence in 2-qp bands of even-even nuclei is also discussed; interesting features are pointed out

The Astrophysical Weeds: Rotational Transitions in Excited Vibrational States

Science.gov (United States)

Alonso, José L.; Kolesniková, Lucie; Alonso, Elena R.; Mata, Santiago

2017-06-01

The number of unidentified lines in the millimeter and submillimeter wave surveys of the interstellar medium has grown rapidly. The major contributions are due to rotational transitions in excited vibrational states of a relatively few molecules that are called the astrophysical weeds. necessary data to deal with spectral lines from astrophysical weeds species can be obtained from detailed laboratory rotational measurements in the microwave and millimeter wave region. A general procedure is being used at Valladolid combining different time and/or frequency domain spectroscopic tools of varying importance for providing the precise set of spectroscopic constants that could be used to search for this species in the ISM. This is illustrated in the present contribution through its application to several significant examples. Fortman, S. M., Medvedev, I. R., Neese, C.F., & De Lucia, F.C. 2010, ApJ,725, 1682 Rotational Spectra in 29 Vibrationally Excited States of Interstellar Aminoacetonitrile, L. Kolesniková, E. R. Alonso, S. Mata, and J. L. Alonso, The Astrophysical Journal Supplement Series 2017, (in press).

Electric dipole moment function of the X1 Sigma/+/ state of CO - Vibration-rotation matrix elements for transitions of gas laser and astrophysical interest

Science.gov (United States)

Chackerian, C., Jr.

1976-01-01

The electric dipole moment function of the ground electronic state of carbon monoxide has been determined by combining numerical solutions of the radial Schrodinger equation with absolute intensity data of vibration-rotation bands. The derived dipole moment function is used to calculate matrix elements of interest to stellar astronomy and of importance in the carbon monoxide laser.

Noncontact measurement of rotating blade vibrations. Doyoku shindo no hisesshoku keisokuho no kenkyu

Energy Technology Data Exchange (ETDEWEB)

Matsuda, Yukio; Endo, Masanori; Sugiyama, Nanahisa; Koshinuma, Takeshi

1989-08-01

The noncontact measurement method of rotating blade vibrations was developed for fans, compressors and turbines, and applied to turbofan engines and industrial gas turbines. The method required no machining of blades and rotor except sensors attached to a casing to detect blade-tips. The method allowed to measure simultaneously the vibration of all blades, by measuring elapsed times of blade-tips rotating from a measuring start point to a detecting point, and detecting the time differences between a vibration and non-vibration condition. The measuring system was composed of the detectors and subsystems for signal processing, control, calculation and display. The vibration wave forms of a few blades and the maximum vibration amplitudes of all the blades were displayed on a realtime basis in an on-line monitoring mode, and an off-line data processing mode was also available for subsequent analyses and reviews. The results of application to existing engines favorably agreed with those of strain gage measurements. 16 refs., 75 figs., 3 tabs.

A brief review of intruder rotational bands and magnetic rotation in the A = 110 mass region

Science.gov (United States)

Banerjee, P.

2018-05-01

Nuclei in the A ∼ 110 mass region exhibit interesting structural features. One of these relates to the process by which specific configurations, built on the excitation of one or more protons across the Z = 50 shell-gap, manifest as collective rotational bands at intermediate spins and gradually lose their collectivity with increase in spin and terminate in a non-collective state at the maximum spin which the configuration can support. These bands are called terminating bands that co-exist with spherical states. Some of these bands are said to terminate smoothly underlining the continuous character of the process by which the band evolves from significant collectivity at low spin to a pure particle-hole non-collective state at the highest spin. The neutron-deficient A ∼ 110 mass region provides the best examples of smoothly terminating bands. The present experimental and theoretical status of such bands in several nuclei with 48 ≤ Z ≤ 52 spanning the 106 ≤ A ≤ 119 mass region have been reviewed in this article. The other noteworthy feature of nuclei in the A ∼ 110 mass region is the observation of regular rotation-like sequences of strongly enhanced magnetic dipole transitions in near-spherical nuclei. These bands, unlike the well-studied rotational sequences in deformed nuclei, arise from a spontaneous symmetry breaking by the anisotropic currents of a few high-j excited particles and holes. This mode of excitation is called magnetic rotation and was first reported in the Pb region. Evidence in favor of the existence of such structures, also called shears bands, are reported in the literature for a large number of Cd, In, Sn and Sb isotope with A ∼ 110. The present article provides a general overview of these reported structures across this mass region. The review also discusses antimagnetic rotation bands and a few cases of octupole correlations in the A = 110 mass region.

Research on mechanism of the large-amplitude and narrow-band vibration of a flexible flat plate in the rectangular channel

Energy Technology Data Exchange (ETDEWEB)

Liu Lifang, E-mail: liu_lifang1106@yahoo.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); State Nuclear Power Software Development Center, Building 1, Compound No. 29, North Third Ring Road, Xicheng District, Beijing 100029 (China); Lu Daogang [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China)

2012-09-15

Highlights: Black-Right-Pointing-Pointer The large amplitude and narrow-band vibration experiment was performed. Black-Right-Pointing-Pointer The added mass theory was used to analyze the test plates' natural vibration characteristics in static water. Black-Right-Pointing-Pointer The occurring condition of the large amplitude and narrow band vibration was investigated. Black-Right-Pointing-Pointer The large amplitude and narrow-band vibration mechanism was investigated. - Abstract: Further experiments and theoretical analysis were performed to investigate mechanism of the large-amplitude and narrow-band vibration behavior of a flexible flat plate in a rectangular channel. Test plates with different thicknesses were adopted in the FIV experiments. The natural vibration characteristics of the flexible flat plates in air were tested, and the added mass theory of column was used to analyze the flexible flat plates' natural vibration characteristics in static water. It was found that the natural vibration frequency of a certain test plate in static water is approximately within the main vibration frequency band of the plate when it was induced to vibrate with the large-amplitude and narrow-band in the rectangular channel. It can be concluded that the harmonic between the flowing fluid and the vibrating plate is one of the key reasons to induce the large-amplitude and narrow-band vibration phenomenon. The occurring condition of the phenomenon and some important narrow-band vibration characteristics of a foursquare fix-supported flexible flat plate were investigated.

Highly vibrationally excited O2 molecules in low-pressure inductively-coupled plasmas detected by high sensitivity ultra-broad-band optical absorption spectroscopy

Science.gov (United States)

Foucher, Mickaël; Marinov, Daniil; Carbone, Emile; Chabert, Pascal; Booth, Jean-Paul

2015-08-01

Inductively-coupled plasmas in pure O2 (at pressures of 5-80 mTorr and radiofrequency power up to 500 W) were studied by optical absorption spectroscopy over the spectral range 200-450 nm, showing the presence of highly vibrationally excited O2 molecules (up to vʺ = 18) by Schumann-Runge band absorption. Analysis of the relative band intensities indicates a vibrational temperature up to 10,000 K, but these hot molecules only represent a fraction of the total O2 density. By analysing the (11-0) band at higher spectral resolution the O2 rotational temperature was also determined, and was found to increase with both pressure and power, reaching 900 K at 80 mTorr 500 W. These measurements were achieved using a new high-sensitivity ultra-broad-band absorption spectroscopy setup, based on a laser-plasma light source, achromatic optics and an aberration-corrected spectrograph. This setup allows the measurement of weak broadband absorbances due to a baseline variability lower than 2   ×   10-5 across a spectral range of 250 nm.

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.

Analysis of rotation-vibration relative equilibria on the example of a tetrahedral four atom molecule

NARCIS (Netherlands)

Efstathiou, K; Sadovskii, DA; Zhilinskii, BI

2004-01-01

We study relative equilibria ( RE) of a nonrigid molecule, which vibrates about a well-defined equilibrium configuration and rotates as a whole. Our analysis unifies the theory of rotational and vibrational RE. We rely on the detailed study of the symmetry group action on the initial and reduced

Resonant vibrations and acoustic radiation of rotating spherical structures.

CSIR Research Space (South Africa)

Shatalov, M

2006-07-01

Full Text Available involved into rotation (precession) with respect to the inertial space with scale factors depending on nature of elastic modes and their numbers. Corresponding scales factors or Bryan’s factors of the vibrating mode’s precession are calculated depending...

Optical model with multiple band couplings using soft rotator structure

Science.gov (United States)

Martyanov, Dmitry; Soukhovitskii, Efrem; Capote, Roberto; Quesada, Jose Manuel; Chiba, Satoshi

2017-09-01

A new dispersive coupled-channel optical model (DCCOM) is derived that describes nucleon scattering on 238U and 232Th targets using a soft-rotator-model (SRM) description of the collective levels of the target nucleus. SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate coupling matrix elements of the generalized optical model. Five rotational bands are coupled: the ground-state band, β-, γ-, non-axial- bands, and a negative parity band. Such coupling scheme includes almost all levels below 1.2 MeV of excitation energy of targets. The "effective" deformations that define inter-band couplings are derived from SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a monopolar deformed potential leading to additional couplings between rotational bands. The present DCCOM describes the total cross section differences between 238U and 232Th targets within experimental uncertainty from 50 keV up to 200 MeV of neutron incident energy. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus (CN) formation cross sections, which is significantly different from the one calculated with rigid-rotor potentials with any number of coupled levels.

Vibrational effects on surface energies and band gaps in hexagonal and cubic ice

International Nuclear Information System (INIS)

Engel, Edgar A.; Needs, Richard J.; Monserrat, Bartomeu

2016-01-01

Surface energies of hexagonal and cubic water ice are calculated using first-principles quantum mechanical methods, including an accurate description of anharmonic nuclear vibrations. We consider two proton-orderings of the hexagonal and cubic ice basal surfaces and three proton-orderings of hexagonal ice prism surfaces, finding that vibrations reduce the surface energies by more than 10%. We compare our vibrational densities of states to recent sum frequency generation absorption measurements and identify surface proton-orderings of experimental ice samples and the origins of characteristic absorption peaks. We also calculate zero point quantum vibrational corrections to the surface electronic band gaps, which range from −1.2 eV for the cubic ice basal surface up to −1.4 eV for the hexagonal ice prism surface. The vibrational corrections to the surface band gaps are up to 12% smaller than for bulk ice.

Transmission of High Frequency Vibrations in Rotating Systems. Application to Cavitation Detection in Hydraulic Turbines

Directory of Open Access Journals (Sweden)

David Valentín

2018-03-01

Full Text Available One of the main causes of damage in hydraulic turbines is cavitation. While not all cavitation appearing in a turbine is of a destructive type, erosive cavitation can severely affect the structure, thus increasing maintenance costs and reducing the remaining useful life of the machine. Of all types of cavitation, the maximum erosion occurs when clouds of bubbles collapse on the runner surface (cloud cavitation. When this occurs it is associated with a substantial increase in noise, and vibrations that are propagated everywhere throughout the machine. The generation of these cavitation clouds may occur naturally or it may be the response to a periodic pressure fluctuation, like the rotor/stator interaction in a hydraulic turbine. Erosive bubble cavitation generates high-frequency vibrations that are modulated by the shedding frequency. Therefore, the methods for the detection of erosive cavitation in hydraulic turbines are based on the measurement and demodulation of high-frequency vibrations. In this paper, the feasibility of detecting erosive cavitation in hydraulic turbines is investigated experimentally in a rotating disk system, which represents a simplified hydraulic turbine structure. The test rig used consists of a rotating disk submerged in a tank of water and confined with nearby axial and radial rigid surfaces. The excitation patterns produced by cloud cavitation are reproduced with a PZT (piezoelectric patch located on the disk. These patterns include pseudo-random excitations of different frequency bands modulated by one low carrier frequency, which model the erosive cavitation characteristics. Different types of sensors have been placed in the stationary and in the rotating parts (accelerometers, acoustic emission (AE, and a microphone in order to detect the excitation pattern. The results obtained for all the sensors tested have been compared in detail for the different excitation patterns applied to the disk. With this information

Faraday Rotation and L Band Oceanographic Measurements

DEFF Research Database (Denmark)

Skou, Niels

2003-01-01

Spaceborne radiometric measurements of the L band brightness temperature over the oceans make it possible to estimate sea surface salinity. However, Faraday rotation in the ionosphere disturbs the signals and must be corrected. Two different ways of assessing the disturbance directly from...

Vibration-resistant Er-doped superfluorescent fiber source incorporating a Faraday rotator mirror

Science.gov (United States)

Zhang, Enkang; Yang, Liu; Gao, Zhongxing; Xue, Bing; Zhang, Yonggang

2018-04-01

Improvement in the mean wavelength vibration stability is crucial to the realization of a high-precision fiber-optic gyroscope. We design a vibration-resistant Er-doped superfluorescent fiber source (VR-EDSFS) incorporated with a Faraday rotator mirror and compare it with the conventional Er-doped superfluorescent fiber source (ED-SFS) under different vibration conditions. As shown by experimental results, the mean wavelength vibration stability of the VR-EDSFS is much better than that of the conventional ED-SFS. Under the 1000 to 2000 Hz vibration condition, the former is just 3.4 ppm, which is about 7 ppm less than the latter over 2 h.

Vibrational bands of luminescent zinc(II)-octaethyl-porphyrin using a polarization-sensitive 'microcopic' multiplex CARS technique

NARCIS (Netherlands)

Otto, Cornelis; Voroshilov, A.; Voroshilov, Artemy; Kruglik, S.; Kruglik, S.G.; Greve, Jan

2001-01-01

Polarization-sensitive, multiplex coherent anti-Stokes Raman scattering (ps-MCARS) has been used to detect the vibrational bands of the highly luminescent zinc(II)-octaethylporphyrin (Zn-OEP). We show here that ps-MCARS can be used to measure the vibrational bands under resonant conditions.

Rotationally resolved pulsed-field ionization photoelectron bands for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12) in the energy range of 17.0-18.2 eV

Energy Technology Data Exchange (ETDEWEB)

Song, Y. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Evans, M. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Ng, C. Y. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Hsu, C.-W. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Jarvis, G. K. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2000-01-15

We have obtained rotationally resolved pulsed-field ionization photoelectron (PFI-PE) spectra for O{sub 2} in the energy range of 17.05-18.13 eV, covering the ionization transitions O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12,N{sup +})(<-)O{sub 2}(X {sup 3}{sigma}{sub g}{sup -},v{sup ''}=0,N{sup ''}). Although these O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}) PFI-PE bands have significant overlaps with vibrational bands for O{sub 2}{sup +}(a {sup 4}{pi}{sub u}) and O{sub 2}{sup +}(X {sup 2}{pi}{sub g}), we have identified all the O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12) bands by simulation of spectra obtained using supersonically cooled O{sub 2} samples with rotational temperatures {approx_equal}20 and 220 K. While these v{sup +}=0-12 PFI-PE bands represent the first rotationally resolved photoelectron data for O{sub 2}{sup +}(A {sup 2}{pi}{sub u}), the PFI-PE bands for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=9 and 10) are the first rotationally resolved spectroscopic data for these levels. The simulation also allows the determination of accurate ionization energies, vibrational constants, and rotational constants for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12). The analysis of the PFI-PE spectra supports the conclusion of the previous emission study that the O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=9 and 10) states are strongly perturbed by a nearby electronic state. (c) 2000 American Institute of Physics.

Basis states for the rotational and vibrational limits of nuclear collective motion

International Nuclear Information System (INIS)

Vanagas, V.; Alishauskas, S.; Kalinauskas, R.; Nadzhakov, E.

1980-01-01

Basis states characterized by quantum numbers traditionally used in the rotational and the vibrational limits are treated in an unified way. An explicit basis construction in the Hilbert space of the collective phenomenological nuclear Hamiltonian generalized to six degrees of freedom in both limits is given. This generalization reduces to including an additional degree of freedom allowing to treat both cases within a collective substance of the complete many-body Hilbert space. A group-theoretical approach is applied. From this point of view the problem is reduced to the construction of a set of U(6)-irreducible states labelled by quantum numbers of two special chains of subgroups adapted for the rotational and vibrational limits. In particular, the generalization is more complicated in the case of the chain for the rotational limits. The explicit construction of a basis for both limits is carried out in two steps: 1) construction of the highest weight state for corresponding group irreducible representation - in the case of the rotational limit U(3) and of the vibrational limit O(5); 2) generating a complete set of states by the projection technique. In this framework it is possible to diagonalize a general phenomenological Hamiltonian in cases different from both limits. It is also possible to calculate transition probabilities induced by any physical quantity

Microwave and Submillimeter-Wave Measurements of HD 12C 16O in the ν 4, ν 5, and ν 6 Bands: Evidence of Vibrational Induced Rotational Axis Switching ("VIRAS")

Science.gov (United States)

Perrin, A.; Flaud, J.-M.; Margulès, L.; Demaison, J.; Mäder, H.; Wörmke, S.

2002-12-01

The rotational spectrum of HDCO in the 4 1, 5 1, and 6 1 excited vibrational states has been investigated in Lille and Kiel using a sample enriched in deuterium. In Lille, the measurements were performed in the millimeter region (160-600 GHz). The spectra in Kiel were recorded using Fourier transform microwave spectrometers in the regions around 8-18 and 18-26 GHz, employing a rectangular waveguide of length 12 m and a circular waveguide of length 36 m, respectively. These results were combined with the 4 1, 5 1, and 6 1 infrared energy levels which were obtained from a previous analysis of FTS spectra of the ν 4 (CHD bend), ν 5 (CHD rocking), and ν 6 bands (out of plane bend) recorded in the 10-μm region at Giessen (A. Perrin, J.-M. Flaud, M. Smirnov, and M. Lock, J. Mol. Spectrosc.203, 175-187 (2000)). The energy level calculation of the 4 1, 5 1, and 6 1 interacting states accounts for the usual A- and B-type Coriolis resonances in the 5 1⇔6 1 and 4 1⇔6 1 off diagonals blocks. In addition, since the energy levels of the 5 1 and 6 1 states are very strongly resonating, it proved necessary, as in our previous study, to use a { Jx, Jz} nonorthorhombic term in the 5 1 and 6 1v-diagonal blocks of the Hamiltonian matrix in order to reproduce properly the observed microwave transitions and infrared energy levels. Therefore, this work confirms that HDCO is a good example of the vibrational induced rotational axis switching ("VIRAS") effect.

Torsion-rotation structure and quasi-symmetric-rotor behaviour for the CH3SH asymmetric CH3-bending and C-H stretching bands of E parentage

Science.gov (United States)

Lees, R. M.; Xu, Li-Hong; Guislain, B. G.; Reid, E. M.; Twagirayezu, S.; Perry, D. S.; Dawadi, M. B.; Thapaliya, B. P.; Billinghurst, B. E.

2018-01-01

High-resolution Fourier transform spectra of the asymmetric methyl-bending and methyl-stretching bands of CH3SH have been recorded employing synchrotron radiation at the FIR beamline of the Canadian Light Source. Analysis of the torsion-rotation structure and relative intensities has revealed the novel feature that for both bend and stretch the in-plane and out-of-plane modes behave much like a Coriolis-coupled l-doublet pair originating from degenerate E modes of a symmetric top. As the axial angular momentum K increases, the energies of the coupled "l = ±1" modes diverge linearly, with effective Coriolis ζ constants typical for symmetric tops. For the methyl-stretching states, separated at K = 0 by only about 1 cm-1, the assigned sub-bands follow a symmetric top Δ(K - l) = 0 selection rule, with only ΔK = -1 transitions observed to the upper l = -1 in-plane A‧ component and only ΔK = +1 transitions to the lower l = +1 out-of-plane A″ component. The K = 0 separation of the CH3-bending states is larger at 9.1 cm-1 with the l-ordering reversed. Here, both ΔK = +1 and ΔK = -1 transitions are seen for each l-component but with a large difference in relative intensity. Term values for the excited state levels have been fitted to J(J + 1) power-series expansions to obtain substate origins. These have then been fitted to a Fourier model to characterize the torsion-K-rotation energy patterns. For both pairs of vibrational states, the torsional energies display the customary oscillatory behaviour as a function of K and have inverted torsional splittings relative to the ground state. The spectra show numerous perturbations, indicating local resonances with the underlying bath of high torsional levels and vibrational combination and overtone states. The overall structure of the two pairs of bands represents a new regime in which the vibrational energy separations, torsional splittings and shifts due to molecular asymmetry are all of the same order, creating a

Sub-Doppler spectroscopy of thioformaldehyde: Excited state perturbations and evidence for rotation-induced vibrational mixing in the ground state

International Nuclear Information System (INIS)

Clouthier, D.J.; Huang, G.; Adam, A.G.; Merer, A.J.

1994-01-01

High-resolution intracavity dye laser spectroscopy has been used to obtain sub-Doppler spectra of transitions to 350 rotational levels in the 4 1 0 band of the A 1 A 2 --X 1 A 1 electronic transition of thioformaldehyde. Ground state combination differences from the sub-Doppler spectra, combined with microwave and infrared data, have been used to improve the ground state rotational and centrifugal distortion constants of H 2 CS. The upper state shows a remarkable number of perturbations. The largest of these are caused by nearby triplet levels, with matrix elements of 0.05--0.15 cm -1 . A particularly clear singlet--triplet avoided crossing in K a ' = 7 has been shown to be caused by interaction with the F 1 component of the 3 1 6 2 vibrational level of the a 3 A 2 state. At least 53% of the S 1 levels show evidence of very small perturbations by high rovibronic levels of the ground state. The number of such perturbations is small at low J, but increases rapidly beyond J=5 such that 40%--80% of the observed S 1 levels of any given J are perturbed by ground state levels. Model calculations show that the density and J dependence of the number of perturbed levels can be explained if there is extensive rotation-induced mixing of the vibrational levels in the ground state

Relaxation processes in rotational motion

International Nuclear Information System (INIS)

Broglia, R.A.

1986-01-01

At few MeV above the yrast line the normally strong correlations among γ-ray energies in a rotational sequence become weaker. This observation can be interpreted as evidence for the damping of rotational motion in hot nuclei. It seems possible to relate the spreading width of the E2-rotational decay strength to the spread in frequency Δω 0 of rotational bands. The origin of these fluctuations is found in: (1) fluctuations in the occupation of special single-particle orbits which contribute a significant part of the total angular momentum; and (2) fluctuations in the moment of inertia induced by vibrations of the nuclear shape. Estimates of Δω 0 done making use of the hundred-odd known discrete rotational bands in the rare-earth region lead, for moderate spin and excitation energies (I ≅ 30 and U ≅ 3 to 4 MeV), to rotational spreading widths of the order of 60 to 160 keV in overall agreement with the data. 24 refs

Study on electromagnetic constants of rotational bands

International Nuclear Information System (INIS)

Abdurazakov, A.A.; Adib, Yu.Sh.; Karakhodzhaev, A.K.

1991-01-01

Values of electromagnetic constant S and rotation bands of odd nuclei with Z=64-70 within the mass number change interval A=153-173 are determined. Values of γ-transition mixing parameter with M1+E2 multipolarity are presented. ρ parameter dependence on mass number A is discussed

[Research on the emission spectrum of NO molecule's γ-band system by corona discharge].

Science.gov (United States)

Zhai, Xiao-dong; Ding, Yan-jun; Peng, Zhi-min; Luo, Rui

2012-05-01

The optical emission spectrum of the gamma-band system of NO molecule, A2 sigma+ --> X2 pi(r), has been analyzed and calculated based on the energy structure of NO molecule' doublet states. By employing the theory of diatomic molecular Spectra, some key parameters of equations for the radiative transition intensity were evaluated theoretically, including the potentials of the doublet states of NO molecule's upper and lower energy levels, the electronic transition moments calculated by using r-centroid approximation method, and the Einstein coefficient of different vibrational and rotational levels. The simulated spectrum of the gamma-band system was calculated as a function of different vibrational and rotational temperature. Compared to the theoretical spectroscopy, the measured results were achieved from corona discharge experiments of NO and N2. The vibrational and rotational temperatures were determined approximately by fitting the measured spectral intensities with the calculated ones.

Basic tests of a rotation seismograph; Kaiten jishinkei no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Matsubayashi, H; Kawamura, S; Watanabe, F; Hirai, Y; Kasahara, K [Nippon Geophysical Prospecting Co. Ltd., Tokyo (Japan)

1996-05-01

For the purpose of developing a rotational seismograph capable of measuring the rotational component of seismic waves, vibratory gyroscopes were installed in the ground for the measurement of vibration of the ground, and the measurements were compared with the values obtained from tests using conventional velocity type seismographs. In the experiment, the plank was hammered on the east side and west side. The seismographs were arranged in two ways: one wherein they were installed at 7 spots at intervals of 1m toward the south beginning at a position 3m south of the vibration source with their rotation axes oriented vertical, with velocity type seismographs provided at the same spots; and the other wherein three rotational seismographs were installed 3m south of the vibration source with their rotation axes respectively oriented vertical, in the direction of N-S, and in the direction of E-W, with a velocity type seismograph provided at the same spot. It was found as the result that the rotational seismograph has a flat band on the lower frequency side and that it may be applied to elastic wave observation across a wide band. Accordingly, it is expected that it will be applied to exploration that uses the SH wave, to structural assessment that uses the Love wave, and to collecting knowledge about the features of natural earthquakes. 2 refs., 8 figs.

Translational, rotational and vibrational temperatures of a gliding arc discharge at atmospheric pressure air

DEFF Research Database (Denmark)

Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas

2014-01-01

and vibrational temperatures of a gliding arc generated at atmospheric pressure air are investigated. Translational temperatures (about 1100 K) were measured by laser-induced Rayleigh scattering, and two-dimensional temperature imaging was performed. Rotational and vibrational temperatures (about 3600 K and 6700...

WAVELETS AND PRINCIPAL COMPONENT ANALYSIS METHOD FOR VIBRATION MONITORING OF ROTATING MACHINERY

OpenAIRE

Bendjama, Hocine; S. Boucherit, Mohamad

2017-01-01

Fault diagnosis is playing today a crucial role in industrial systems. To improve reliability, safety and efficiency advanced monitoring methods have become increasingly important for many systems. The vibration analysis method is essential in improving condition monitoring and fault diagnosis of rotating machinery. Effective utilization of vibration signals depends upon effectiveness of applied signal processing techniques. In this paper, fault diagnosis is performed using a com...

Microscopic structure of high-spin vibrational states in superdeformed A=190 nuclei

Energy Technology Data Exchange (ETDEWEB)

Nakatsukasa, Takashi [Chalk River Labs., Ontario (Canada); Matsuyanagi, Kenichi [Kyoto Univ. (Japan); Mizutori, Shoujirou [Oak Ridge National Lab., TN (United States)] [and others

1996-12-31

Microscopic RPA calculations based on the cranked shell model are performed to investigate the quadrupole and octupole correlations for excited superdeformed (SD) bands in even-even A=190 nuclei. The K = 2 octupole vibrations are predicted to be the lowest excitation modes at zero rotational frequency. The Coriolis coupling at finite frequency produces different effects depending on the neutron and proton number of nucleus. The calculations also indicate that some collective excitations may produce moments of inertia almost identical to those of the yrast SD band. An interpretation of the observed excited bands invoking the octupole vibrations is proposed, which suggests those octupole vibrations may be prevalent in even-even SD A=190 nuclei.

The SU(3) structure of rotational states in heavy deformed nuclei

International Nuclear Information System (INIS)

Jarrio, M.; Wood, J.L.; Rowe, D.J.

1991-01-01

The SU(3) coupling scheme provides an informative basis for the expansion of shell-model wave functions and their interpretation in collective-model terms. We show in this paper that it is possible, using the coupled-rotor-vibrator model, to infer averages of the distributions of SU(3) representation labels in heavy rotational nuclei by direct interpretation of physically observed E2 transition rates and quadrupole moments. We find that the distributions of SU(3) representation labels have nearly constant average values for states belonging to some well-defined rotational bands. These are bands of states having B(E2) values and quadrupole moments that follow the predictions of the rotor model. Such bands are interpreted as soft SU(3) bands in parallel with the concept of a soft rotor band with vibrational-shape fluctuations. The concept of a soft SU(3) band and its implications for beta-vibrational excited bands is developed. The average SU(3) representation labels inferred from experiment are interpreted by calculating those implied by the Nilsson model. An analysis of the SU(3) content of Nilsson wave functions also leads to two remarkable predictions. The first is that, in the asymptotic limit, the Nilsson model implies intrinsic states for a rotor band that are beta rigid. The second is that, although the intrinsic Nilsson state is axially symmetric, it generates a sequence of K=0, 2, 4,...bands. (orig.)

Predicting superdeformed rotational band-head spin in A ∼ 190 mass region using variable moment of inertia model

International Nuclear Information System (INIS)

Uma, V.S.; Goel, Alpana; Yadav, Archana; Jain, A.K.

2016-01-01

The band-head spin (I 0 ) of superdeformed (SD) rotational bands in A ∼ 190 mass region is predicted using the variable moment of inertia (VMI) model for 66 SD rotational bands. The superdeformed rotational bands exhibited considerably good rotational property and rigid behaviour. The transition energies were dependent on the prescribed band-head spins. The ratio of transition energies over spin Eγ/ 2 I (RTEOS) vs. angular momentum (I) have confirmed the rigid behaviour, provided the band-head spin value is assigned correctly. There is a good agreement between the calculated and the observed transition energies. This method gives a very comprehensive interpretation for spin assignment of SD rotational bands which could help in designing future experiments for SD bands. (author)

Simultaneous acquisition of pure rotational and vibrational nitrogen spectra using three-laser CARS

International Nuclear Information System (INIS)

Lucht, R.P.; Maris, M.A.

1987-01-01

The author used three-laser coherent anti-Stokes Raman scattering to acquire simultaneously the pure rotational and vibrational spectra from the nitrogen molecule. The energy level schematic for the three-laser CARS process is shown in this paper. Frequency-doubled Nd:YAG laser radiation at frequency ω/sub 1/ is used to pump a broadband dye laser which lasers at a range of frequencies ω/sub s/ and a narrowband dye laser with frequency ω/sub 2/. The three-beams are focused to a common CARS probe volume using a three-dimensional phase-matching geometry. A CARS polarization is established when the frequency difference ω/sub 1/ - ω/sub s/ corresponds to a vibrational Raman resonance. The vibrational polarization scatters the incident ω/sub 2/ beam to produce anti-Stokes radiation at frequency ω/sub 1/ - ω/sub s/ + ω/sub 2/. In a similar fashion, a CARS polarization is also established when the frequency difference ω/sub 2/ - ω/sub s/ is equal to a pure rotational Raman resonance. The pure rotational polarization scatters the Nd:YAG laser radiation at ω/sub 1/ to produce anti-Stokes radiation at ω/sub 2/ - ω/sub s/ + ω/sub 1/

Vibration of rotating-shaft design spindles with flexible bases

Science.gov (United States)

Tseng, Chaw-Wu

The purpose of this study is to demonstrate an accurate mathematical model predicting forced vibration of rotating-shaft HDD spindle motors with flexible stationary parts. The mathematical model consists of three parts: a rotating part, a stationary part, and bearings. The rotating part includes a flexible hub, a flexible shaft press-fit into the hub, and N elastic disks mounted on the hub. The stationary part can include motor bracket (stator), base casting, and top cover. The bearings under consideration can be ball bearings or hydrodynamic bearings (HDB). The rotating disks are modelled through the classical plate theory. The rotating part (except the disks) and the stationary part are modelled through finite element analyses (FEA). With mode shapes and natural frequencies obtained from FEA, the kinetic and potential energies of the rotating and stationary parts are formulated and discretized to compensate for the gyroscopic effects from rotation. Finally, use of Lagrange equation results in the equations of motion. To verify the mathematical model, frequency response functions are measured experimentally for an HDB spindle carrying two identical disks at motor and drive levels. Experimental measurements agree very well with theoretical predictions not only in resonance frequency but also in resonance amplitude.

Overtone spectroscopy of the hydroxyl stretch vibration in hydroxylamine (NH2OH)

International Nuclear Information System (INIS)

Scott, J.L.; Luckhaus, D.; Brown, S.S.; Crim, F.F.

1995-01-01

We present photoacoustic spectra of the second (3ν OH ), third (4ν OH ), and fourth (5ν OH ) overtone bands of the hydroxyl stretch vibration in hydroxylamine. Asymmetric rotor simulations of the rovibrational contours provide rotational constants and an estimate of the homogeneous linewidth. The fourth overtone band appears anomalously broad relative to the two lower bands, reflecting a sharp increase in the rate of intramolecular vibrational energy redistribution (IVR). By contrast, the calculated density of states increases smoothly with energy. The homogeneous linewidth of the fourth overtone transition is similar to that measured by Luo et al. [J. Chem. Phys. 93, 9194 (1990)] for the predissociative sixth overtone band, supporting the conclusion that the broadening arises from increased (ro)vibrational coupling at an energy between the third and fourth overtone states

Rotational Spectra in 29 Vibrationally Excited States of Interstellar Aminoacetonitrile

Energy Technology Data Exchange (ETDEWEB)

Kolesniková, L.; Alonso, E. R.; Mata, S.; Alonso, J. L. [Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid (Spain)

2017-04-01

We report a detailed spectroscopic investigation of the interstellar aminoacetonitrile, a possible precursor molecule of glycine. Using a combination of Stark and frequency-modulation microwave and millimeter wave spectroscopies, we observed and analyzed the room-temperature rotational spectra of 29 excited states with energies up to 1000 cm{sup −1}. We also observed the {sup 13}C isotopologues in the ground vibrational state in natural abundance (1.1%). The extensive data set of more than 2000 new rotational transitions will support further identifications of aminoacetonitrile in the interstellar medium.

Fault Diagnosis for Rotating Machinery Using Vibration Measurement Deep Statistical Feature Learning

Directory of Open Access Journals (Sweden)

Chuan Li

2016-06-01

Full Text Available Fault diagnosis is important for the maintenance of rotating machinery. The detection of faults and fault patterns is a challenging part of machinery fault diagnosis. To tackle this problem, a model for deep statistical feature learning from vibration measurements of rotating machinery is presented in this paper. Vibration sensor signals collected from rotating mechanical systems are represented in the time, frequency, and time-frequency domains, each of which is then used to produce a statistical feature set. For learning statistical features, real-value Gaussian-Bernoulli restricted Boltzmann machines (GRBMs are stacked to develop a Gaussian-Bernoulli deep Boltzmann machine (GDBM. The suggested approach is applied as a deep statistical feature learning tool for both gearbox and bearing systems. The fault classification performances in experiments using this approach are 95.17% for the gearbox, and 91.75% for the bearing system. The proposed approach is compared to such standard methods as a support vector machine, GRBM and a combination model. In experiments, the best fault classification rate was detected using the proposed model. The results show that deep learning with statistical feature extraction has an essential improvement potential for diagnosing rotating machinery faults.

Fault Diagnosis for Rotating Machinery Using Vibration Measurement Deep Statistical Feature Learning.

Science.gov (United States)

Li, Chuan; Sánchez, René-Vinicio; Zurita, Grover; Cerrada, Mariela; Cabrera, Diego

2016-06-17

Fault diagnosis is important for the maintenance of rotating machinery. The detection of faults and fault patterns is a challenging part of machinery fault diagnosis. To tackle this problem, a model for deep statistical feature learning from vibration measurements of rotating machinery is presented in this paper. Vibration sensor signals collected from rotating mechanical systems are represented in the time, frequency, and time-frequency domains, each of which is then used to produce a statistical feature set. For learning statistical features, real-value Gaussian-Bernoulli restricted Boltzmann machines (GRBMs) are stacked to develop a Gaussian-Bernoulli deep Boltzmann machine (GDBM). The suggested approach is applied as a deep statistical feature learning tool for both gearbox and bearing systems. The fault classification performances in experiments using this approach are 95.17% for the gearbox, and 91.75% for the bearing system. The proposed approach is compared to such standard methods as a support vector machine, GRBM and a combination model. In experiments, the best fault classification rate was detected using the proposed model. The results show that deep learning with statistical feature extraction has an essential improvement potential for diagnosing rotating machinery faults.

Large-amplitude and narrow-band vibration phenomenon of a foursquare fix-supported flexible plate in a rigid narrow channel

Energy Technology Data Exchange (ETDEWEB)

Liu Lifang, E-mail: liu_lifang1106@yahoo.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Lu Daogang, E-mail: ludaogang@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Li Yang, E-mail: qinxiuyi@sina.com [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Zhang Pan, E-mail: zhangpan@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Niu Fenglei, E-mail: niufenglei@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China)

2011-08-15

Highlights: > FIV of a foursquare fix-supported flexible plate exposed to axial flow was studied. > Special designed test section and advanced measuring equipments were adopted. > The narrow-band vibration phenomenon with large amplitude was observed. > Line of plate's vibration amplitude and flow rate was investigated. > The phenomenon and the measurement error were analyzed. - Abstract: An experiment was performed to analyze the flow-induced vibration behavior of a foursquare fix-supported flexible plate exposed to the axial flow within a rigid narrow channel. The large-amplitude and narrow-band vibration phenomenon was observed in the experiment when the flow velocity varied with the range of 0-5 m/s. The occurring condition and some characteristics of the large-amplitude and narrow-band vibrations were investigated.

Magnetostrictive patch sensor system for battery-less real-time measurement of torsional vibrations of rotating shafts

Science.gov (United States)

Lee, Jun Kyu; Seung, Hong Min; Park, Chung Il; Lee, Joo Kyung; Lim, Do Hyeong; Kim, Yoon Young

2018-02-01

Real-time uninterrupted measurement for torsional vibrations of rotating shafts is crucial for permanent health monitoring. So far, strain gauge systems with telemetry units have been used for real-time monitoring. However, they have a critical disadvantage in that shaft operations must be stopped intermittently to replace telemetry unit batteries. To find an alternative method to carry out battery-less real-time measurement for torsional vibrations of rotating shafts, a magnetostrictive patch sensor system was proposed in the present study. Since the proposed sensor does not use any powered telemetry system, no battery is needed and thus there is no need to stop rotating shafts for battery replacement. The proposed sensor consists of magnetostrictive patches and small magnets tightly bonded onto a shaft. A solenoid coil is placed around the shaft to convert magnetostrictive patch deformation by shaft torsional vibration into electric voltage output. For sensor design and characterization, investigations were performed in a laboratory on relatively small-sized stationary solid shaft. A magnetostrictive patch sensor system was then designed and installed on a large rotating propulsion shaft of an LPG carrier ship in operation. Vibration signals were measured using the proposed sensor system and compared to those measured with a telemetry unit-equipped strain gauge system.

Molecular vibration-rotation spectra starting from the Fues potential

International Nuclear Information System (INIS)

Ley Koo, E.

1976-01-01

The solution of Schroedinger's equation for the Fues potential is analyzed and compared with the corresponding problems for the Coulomb, harmonic oscillator and molecular potentials. These comparisons allow us to emphasize certain pedagogical, conceptual and computational advantages of the Fues potential which make it a favorable alternative as the starting point in the analysis of molecular vibration-rotation and in the determination of potential energy curves. (author)

Initial vibrational and rotational yields from subexcitation electrons in molecular hydrogen

International Nuclear Information System (INIS)

Douthat, D.A.

1987-01-01

As the energy of a single source electron injected into a molecular gas is degraded through collisions, initial products include secondary electrons, ions, and excited molecules. Electrons with kinetic energies less than the minimum required for excitation of the lowest electronic state are given the designation subexcitation electrons. These electrons are still capable of exciting vibrational and rotational states of molecular gases. In this calculation, the initial numbers of vibrational and rotational excitations (yields) produced as the subexcitation electrons undergo further energy degradation are determined for molecular hydrogen. The calculation requires a complete set of cross section data for numerical solution of the Boltzmann equation. The initial energy distribution of electrons is taken to be the subexcitation distribution which was determined previously. The initial yields are tabulated for gas temperatures from 50 K to 1500 K for a source electron with initial energy 10 keV. 26 references

Self-Tuning Vibration Control of a Rotational Flexible Timoshenko Arm Using Neural Networks

Directory of Open Access Journals (Sweden)

Minoru Sasaki

2012-01-01

Full Text Available A self-tuning vibration control of a rotational flexible arm using neural networks is presented. To the self-tuning control system, the control scheme consists of gain tuning neural networks and a variable-gain feedback controller. The neural networks are trained so as to make the root moment zero. In the process, the neural networks learn the optimal gain of the feedback controller. The feedback controller is designed based on Lyapunov's direct method. The feedback control of the vibration of the flexible system is derived by considering the time rate of change of the total energy of the system. This approach has the advantage over the conventional methods in the respect that it allows one to deal directly with the system's partial differential equations without resorting to approximations. Numerical and experimental results for the vibration control of a rotational flexible arm are discussed. It verifies that the proposed control system is effective at controlling flexible dynamical systems.

Directional Wigner-Ville distribution and its application for rotating-machinery condition monitoring

International Nuclear Information System (INIS)

Kim, Dong Wan; Ha, Jae HOng; Shin, Hae Gon; Lee, Yoon Hee; Kim, Young Baik

1996-01-01

Vibration analysis is one of the most powerful tools available for the detection and isolation of incipient faults in mechanical systems. The methods of vibration analysis in use today and under continuous study are broad band vibration monitoring, time domain analysis, and frequency domain analysis. In recent years, great interest has been generated concerning the use of time-frequency representation and its application for a machinery diagnostics and condition monitoring system. The objective of the research described in this paper was to develop a new diagnostic tool for the rotating machinery. This paper introduces a new time-frequency representation, Directional Wigner-Ville Distribution, which analyses the time-frequency structure of the rotating machinery vibration

Vibrational-rotational temperature measurement of N2 in the lower thermosphere by the rocket experiment

Science.gov (United States)

Kurihara, J.; Oyama, K.; Suzuki, K.; Iwagami, N.

The vibrational temperature (Tv), the rotational temperature (Tr) and the density of atmospheric N2 between 100 - 150 km were measured in situ by a sounding rocket S310-30, over Kagoshima, Japan at 10:30 UT on February 6, 2002. The main purpose of this rocket experiment is to study the dynamics and the thermal energy budget in the lower thermosphere. N2 was ionized using an electron gun and the emission of the 1st negative bands of N2+ was measured by a sensitive spectrometer. Tv and Tr were determined by fitting the observed spectrum for the simulated spectrum, and the number density was deduced from the intensities of the spectrum. We will report preliminary results of our measurement and discuss the observed thermal structure that indicates the effect of tides and gravity waves.

Spectroscopic investigation of the vibrational quasi-continuum arising from internal rotation of a methyl group

Energy Technology Data Exchange (ETDEWEB)

Hougen, J.T. [NIST, Gaithersburg, MD (United States)

1993-12-01

The goal of this project is to use spectroscopic techniques to investigate in detail phenomena involving the vibrational quasi-continuum in a simple physical system. Acetaldehyde was chosen for the study because: (i) methyl groups have been suggested to be important promotors of intramolecular vibrational relaxation, (ii) the internal rotation of a methyl group is an easily describle large-amplitude motion, which should retain its simple character even at high levels of excitation, and (iii) the aldehyde carbonyl group offers the possibility of both vibrational and electronic probing. The present investigation of the ground electronic state has three parts: (1) understanding the {open_quotes}isolated{close_quotes} internal-rotation motion below, at, and above the top of the torsional barrier, (2) understanding in detail traditional (bond stretching and bending) vibrational fundamental and overtone states, and (3) understanding interactions involving states with multiquantum excitations of at least one of these two kinds of motion.

Nonlinear modeling of tuned liquid dampers (TLDs) in rotating wind turbine blades for damping edgewise vibrations

DEFF Research Database (Denmark)

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

2015-01-01

Tuned liquid dampers (TLDs) utilize the sloshing motion of the fluid to suppress structural vibrations and become a natural candidate for damping vibrations in rotating wind turbine blades. The centrifugal acceleration at the tip of a wind turbine blade can reach a magnitude of 7–8g. This facilit......Tuned liquid dampers (TLDs) utilize the sloshing motion of the fluid to suppress structural vibrations and become a natural candidate for damping vibrations in rotating wind turbine blades. The centrifugal acceleration at the tip of a wind turbine blade can reach a magnitude of 7–8g...... free-surface elevation equally well, the one-mode model can still be utilized for the design of TLD. Parametric optimization of the TLD is carried out based on the one-mode model, and the optimized damper effectively improves the dynamic response of wind turbine blades....

Free vibration analysis of a multiple rotating nano-beams system based on the Eringen nonlocal elasticity theory

Energy Technology Data Exchange (ETDEWEB)

Ghafarian, M.; Ariaei, A., E-mail: ariaei@eng.ui.ac.ir [Department of Mechanical Engineering, Faculty of Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of)

2016-08-07

The free vibration analysis of a multiple rotating nanobeams' system applying the nonlocal Eringen elasticity theory is presented. Multiple nanobeams' systems are of great importance in nano-optomechanical applications. At nanoscale, the nonlocal effects become non-negligible. According to the nonlocal Euler-Bernoulli beam theory, the governing partial differential equations are derived by incorporating the nonlocal scale effects. Assuming a structure of n parallel nanobeams, the vibration of the system is described by a coupled set of n partial differential equations. The method involves a change of variables to uncouple the equations and the differential transform method as an efficient mathematical technique to solve the nonlocal governing differential equations. Then a number of parametric studies are conducted to assess the effect of the nonlocal scaling parameter, rotational speed, boundary conditions, hub radius, and the stiffness coefficients of the elastic interlayer media on the vibration behavior of the coupled rotating multiple-carbon-nanotube-beam system. It is revealed that the bending vibration of the system is significantly influenced by the rotational speed, elastic mediums, and the nonlocal scaling parameters. This model is validated by comparing the results with those available in the literature. The natural frequencies are in a reasonably good agreement with the reported results.

Band Width of Acoustic Resonance Frequency Relatively Natural Frequency of Fuel Rod Vibration

Energy Technology Data Exchange (ETDEWEB)

Proskuryakov, Konstantin Nicolaevich; Moukhine, V.S.; Novikov, K.S.; Galivets, E.Yu. [MPEI - TU, 14, Krasnokazarmennaya str., Moscow, 111250 (Russian Federation)

2009-06-15

In flow induced vibrations the fluid flow is the energy source that causes vibration. Acoustic resonance in piping may lead to severe problems due to over-stressing of components or significant losses of efficiency. Steady oscillatory flow in NPP primary loop can be induced by the pulsating flow introduced by reactor circulating pump or may be set up by self-excitation. Dynamic forces generated by the turbulent flow of coolant in reactor cores cause fuel rods (FR) and fuel assembly (FA) to vibrate. Flow-induced FR and FA vibrations can generally be broken into three groups: large amplitude 'resonance type' vibrations, which can cause immediate rod failure or severe damage to the rod and its support structure, middle amplitude 'within bandwidth of resonance frequency type' vibrations responsible for more gradual wear and fatigue at the contact surface between the fuel cladding and rod support and small amplitude vibrations, 'out of bandwidth of resonance frequency type' responsible for permissible wear and fatigue at the contact surface between the fuel cladding and rod support. Ultimately, these vibration types can result in a cladding breach, and therefore must be accounted for in the thermal hydraulic design of FR and FA and reactor internals. In paper the technique of definition of quality factor (Q) of acoustic contour of the coolant is presented. The value of Q defines a range of frequencies of acoustic fluctuations of the coolant within which the resonance of oscillations of the structure and the coolant is realized. Method of evaluation of so called band width (BW) of acoustic resonance frequency is worked out and presented in the paper. BW characterises the range of the frequency of coolant pressure oscillations within which the frequency of coolant pressure oscillations matches the fuel assembly's natural frequency of vibration (its resonance frequency). Paper show the way of detuning acoustic resonance from natural

Bayesian analysis of rotating machines - A statistical approach to estimate and track the fundamental frequency

DEFF Research Database (Denmark)

Pedersen, Thorkild Find

2003-01-01

frequency and the related frequencies as orders of the fundamental frequency. When analyzing rotating or reciprocating machines it is important to know the running speed. Usually this requires direct access to the rotating parts in order to mount a dedicated tachometer probe. In this thesis different......Rotating and reciprocating mechanical machines emit acoustic noise and vibrations when they operate. Typically, the noise and vibrations are concentrated in narrow frequency bands related to the running speed of the machine. The frequency of the running speed is referred to as the fundamental...

Monitoring of Rotor-Stator Interaction in Pump-Turbine Using Vibrations Measured with On-Board Sensors Rotating with Shaft

Directory of Open Access Journals (Sweden)

Cristian G. Rodriguez

2014-01-01

Full Text Available Current trends in design of pump-turbines have led into higher rotor-stator interaction (RSI loads over impeller-runner. These dynamic loads are of special interest having produced catastrophic failures in pump-turbines. Determining RSI characteristics facilitates the proposal of actions that will prevent these failures. Pressure measurements all around the perimeter of the impeller-runner are appropriate to monitor and detect RSI characteristics. Unfortunately most installed pump-turbines are not manufactured with in-built pressure sensors in appropriate positions to monitor RSI. For this reason, vibration measurements are the preferred method to monitor RSI in industry. Usually vibrations are measured in two perpendicular radial directions in bearings where valuable information could be lost due to bearing response. In this work, in order to avoid the effect of bearing response on measurement, two vibration sensors are installed rotating with the shaft. The RSI characteristics obtained with pressure measurements were compared to those determined using vibration measurements. The RSI characteristics obtained with pressure measurements were also determined using vibrations measured rotating with shaft. These RSI characteristics were not possible to be determined using the vibrations measured in guide bearing. Finally, it is recommended to measure vibrations rotating with shaft to detect RSI characteristics in installed pump-turbines as a more practical and reliable method to monitor RSI characteristics.

Supervision of the vibration of rotating components

International Nuclear Information System (INIS)

1982-06-01

The aim of the investifation was to plead for the systematization and uniformity of surveillance and to form a source of information to the makers of instruments, suppliers of engines, consultants and others. Two essential topics are treated, namely rotor dynamics and measuring methods for vibration control. An inventory of damages and problems of rotating machinery is presented. Recommendations concerning various supervision programs of reactor safety, the importance of components, risk of missiles and erroreous operations are given along with instructions how to get hold of suitable instruments. Experience from nuclear power plants is said to be essential. Experimental activity at Ringhals and/or Forsmark power plant is proposed. (G.B.)

Effect of rotation and magnetic field on free vibrations in a spherical non-homogeneous embedded in an elastic medium

Science.gov (United States)

Bayones, F. S.; Abd-Alla, A. M.

2018-06-01

The prime objective of the present paper is to analyze the effect of magnetic field and rotation on the free vibrations of an elastic hollow sphere. The one-dimensional equation of motion is solved in terms of radial displacement. The frequency equation is obtained when the boundaries are free and fixed boundary conditions. The determination is concerned with the eigenvalues of the natural frequency of the free vibrations in the case of harmonic vibrations. The natural frequencies and the mode shapes are calculated numericall and the effects of rotation and magnetic field are discussed. It was shown that the dispersion curves of waves were significantly influenced by the magnetic field and rotation of the elastic sphere.

Comparison of methods for separating vibration sources in rotating machinery

Science.gov (United States)

Klein, Renata

2017-12-01

Vibro-acoustic signatures are widely used for diagnostics of rotating machinery. Vibration based automatic diagnostics systems need to achieve a good separation between signals generated by different sources. The separation task may be challenging, since the effects of the different vibration sources often overlap. In particular, there is a need to separate between signals related to the natural frequencies of the structure and signals resulting from the rotating components (signal whitening), as well as a need to separate between signals generated by asynchronous components like bearings and signals generated by cyclo-stationary components like gears. Several methods were proposed to achieve the above separation tasks. The present study compares between some of these methods. The paper also presents a new method for whitening, Adaptive Clutter Separation, as well as a new efficient algorithm for dephase, which separates between asynchronous and cyclo-stationary signals. For whitening the study compares between liftering of the high quefrencies and adaptive clutter separation. For separating between the asynchronous and the cyclo-stationary signals the study compares between liftering in the quefrency domain and dephase. The methods are compared using both simulated signals and real data.

Free and forced vibrations of an eccentrically rotating string on a viscoelastic foundation

Science.gov (United States)

Soedel, S. M.; Soedel, W.

1989-12-01

Equations of motion of an eccentrically rotating cord on a viscoelastic foundation, derived by way of Hamilton's principle, are solved for free and forced vibrations. The natural frequencies during rotation are bifurcations of the stationary string values. The natural modes are complex and can be interpreted as mode pairs spinning with and against the string rotation. The general forced solution is expanded in terms of these complex modes. Results are given for an example of steady state harmonic response because of its practical significance to aircraft or automobile tire design.

Fluorescence Imaging of Rotational and Vibrational Temperature in a Shock Tunnel Nozzle Flow

Science.gov (United States)

Palma, Philip C.; Danehy, Paul M.; Houwing, A. F. P.

2003-01-01

Two-dimensional rotational and vibrational temperature measurements were made at the nozzle exit of a free-piston shock tunnel using planar laser-induced fluorescence. The Mach 7 flow consisted predominantly of nitrogen with a trace quantity of nitric oxide. Nitric oxide was employed as the probe species and was excited at 225 nm. Nonuniformities in the distribution of nitric oxide in the test gas were observed and were concluded to be due to contamination of the test gas by driver gas or cold test gas.The nozzle-exit rotational temperature was measured and is in reasonable agreement with computational modeling. Nonlinearities in the detection system were responsible for systematic errors in the measurements. The vibrational temperature was measured to be constant with distance from the nozzle exit, indicating it had frozen during the nozzle expansion.

Vibrot, a simple device for the conversion of vibration into rotation mediated by friction: preliminary evaluation.

Directory of Open Access Journals (Sweden)

Ernesto Altshuler

Full Text Available While "vibrational noise" induced by rotating components of machinery is a common problem constantly faced by engineers, the controlled conversion of translational into rotational motion or vice-versa is a desirable goal in many scenarios ranging from internal combustion engines to ultrasonic motors. In this work, we describe the underlying physics after isolating a single degree of freedom, focusing on devices that convert a vibration along the vertical axis into a rotation around this axis. A typical Vibrot (as we label these devices consists of a rigid body with three or more cantilevered elastic legs attached to its bottom at an angle. We show that these legs are capable of transforming vibration into rotation by a "ratchet effect", which is caused by the anisotropic stick-slip-flight motion of the leg tips against the ground. Drawing an analogy with the Froude number used to classify the locomotion dynamics of legged animals, we discuss the walking regime of these robots. We are able to control the rotation frequency of the Vibrot by manipulating the shaking amplitude, frequency or waveform. Furthermore, we have been able to excite Vibrots with acoustic waves, which allows speculating about the possibility of reducing the size of the devices so they can perform tasks into the human body, excited by ultrasound waves from the outside.

A low noise discrete velocity method for the Boltzmann equation with quantized rotational and vibrational energy

Science.gov (United States)

Clarke, Peter; Varghese, Philip; Goldstein, David

2018-01-01

A discrete velocity method is developed for gas mixtures of diatomic molecules with both rotational and vibrational energy states. A full quantized model is described, and rotation-translation and vibration-translation energy exchanges are simulated using a Larsen-Borgnakke exchange model. Elastic and inelastic molecular interactions are modeled during every simulated collision to help produce smooth internal energy distributions. The method is verified by comparing simulations of homogeneous relaxation by our discrete velocity method to numerical solutions of the Jeans and Landau-Teller equations, and to direct simulation Monte Carlo. We compute the structure of a 1D shock using this method, and determine how the rotational energy distribution varies with spatial location in the shock and with position in velocity space.

The Shock and Vibration Digest. Volume 12, Number 2,

Science.gov (United States)

1980-02-01

Structural Analysis lowest few frequencies are required and are more economical than frequency search methods if band- widths of the matrices are large...1973). Inst. Math. Applic., 22, pp 401.410 (1978). 77. Gupta, K.K., "Numerical Analysis of Free Vibrations of Damped Rotating Structures," 66. Pestel ...the program ,.J.G.S. ¢F1 EDITORS RATTLE SPACE DYNAMIC ANALYSIS AND DESIGN At the 50th Shock and Vibration Symposium in October, Robert Hager presented

Opening and closing of band gaps in magnonic waveguide by rotating the triangular antidots - A micromagnetic study

Science.gov (United States)

Vivek, T.; Bhoomeeswaran, H.; Sabareesan, P.

2018-05-01

Spin waves in ID periodic triangular array of antidots are encarved in a permalloy magnonic waveguide is investigated through micromagnetic simulation. The effect of the rotating array of antidots and in-plane rotation of the scattering centers on the band structure are investigated, to indicate new possibilities of fine tuning of spin-wave filter pass and stop bands. The results show that, the opening and closing of band gaps paves a way for band pass and stop filters on waveguide. From the results, the scattering center and strong spatial distribution field plays crucible role for controlling opening and closing bandgap width of ˜12 GHz for 0° rotation. We have obtained a single narrow bandgap of width 1GHz is obtained for 90° rotation of the antidot. Similarly, the tunability is achieved for desired microwave applications done by rotating triangular antidots with different orientation.

Test of Magnetic Rotation near the band head in ^197,198Pb

Science.gov (United States)

Krücken, R.; Clark, R. M.; Deleplanque, M. A.; Diamond, R. M.; Fallon, P.; Macchiavelli, A. O.; Lee, I. Y.; Schmid, G. J.; Stephens, F. S.; Vetter, K.; Dewald, A.; Peusquens, R.; von Brentano, P.; Baldsiefen, G.; Chmel, S.; Hübel, H.; Becker, J. A.; Bernstein, L. A.; Hauschild, K.

1998-04-01

The concept of magnetic rotation is tested near the band head of shears-bands in ^197,198Pb by means of a lifetime experiment with the recoil distance method (RDM). The experiment was performed using the Gammasphere array in conjunction with the Cologne Plunger. The B(M1) values extracted from the measured lifetimes can prove the applicability of the concept of magnetic rotation for the states near the band head of these shears bands. The RDM results are compared with tilted axis cranking and shell model calculations. Furthermore the results will be used to test earlier DSAM lifetime measurements for states at higher spins. Preliminary results of this topic will be presented. This work is supported by DOE grant numbers DE-AC03-76SF00098 (LBNL), DE-FG02-91ER40609 (Yale), W-7405-ENG-48 (LLNL) and by the German BMBF for Cologne (No. 06 OK 668) and Bonn.

Two-dimensional vibrational spectroscopy of the amide I band of crystalline acetanilide: Fermi resonance, conformational substates, or vibrational self-trapping?

Science.gov (United States)

Edler, J.; Hamm, P.

2003-08-01

Two-dimensional infrared (2D-IR) spectroscopy is applied to investigate acetanilide, a molecular crystal consisting of quasi-one-dimensional hydrogen bonded peptide units. The amide-I band exhibits a double peak structure, which has been attributed to different mechanisms including vibrational self-trapping, a Fermi resonance, or the existence of two conformational substates. The 2D-IR spectrum of crystalline acetanilide is compared with that of two different molecular systems: (i) benzoylchloride, which exhibits a strong symmetric Fermi resonance and (ii) N-methylacetamide dissolved in methanol which occurs in two spectroscopically distinguishable conformations. Both 2D-IR spectra differ significantly from that of crystalline acetanilide, proving that these two alternative mechanisms cannot account for the anomalous spectroscopy of crystalline acetanilide. On the other hand, vibrational self-trapping of the amide-I band can naturally explain the 2D-IR response.

Bibliography on electron collisions with molecules: rotational and vibrational excitations, 1980-2000

International Nuclear Information System (INIS)

Itikawa, Yukikazu

2001-04-01

A list of papers reporting cross sections for electron-impact excitations of rotational and vibrational states of molecules is presented. The list includes both the theoretical and the experimental papers published in 1980-2000. An index by molecular species is provided at the end of the bibliography. (author)

β decays on the rotational levels of the 5/2+[642] 169Yb band

International Nuclear Information System (INIS)

Dzhelepov, B.S.; Zhukovskij, N.N.; Shestopalova, S.A.

1993-01-01

Competing 169 Lu β decays into rotational levels of 5/2 + [642] 169 Yb band are considered. Schemes of resolved β decay into 3 levels of deformed nucleus rotational bands, γ transitions linked with excitation and discharge of 169 Yb 5/2, 7/2, 9/2, 5/2 + [642] levels are presented. Matrix elements of axial-vector decay are determined. Data on 12 γ transitions in 169 Lu are presented

Rotation-vibrational spectra of diatomic molecules and nuclei with Davidson interactions

CERN Document Server

Rowe, D J

1998-01-01

Complete rotation-vibrational spectra and electromagnetic transition rates are obtained for Hamiltonians of diatomic molecules and nuclei with Davidson interactions. Analytical results are derived by dynamical symmetry methods for diatomic molecules and a liquid-drop model of the nucleus. Numerical solutions are obtained for a many-particle nucleus with quadrupole Davidson interactions within the framework of the microscopic symplectic model. (author)

An Efficient Method of Vibration Diagnostics For Rotating Machinery Using a Decision Tree

Directory of Open Access Journals (Sweden)

Bo Suk Yang

2000-01-01

Full Text Available This paper describes an efficient method to automatize vibration diagnosis for rotating machinery using a decision tree, which is applicable to vibration diagnosis expert system. Decision tree is a widely known formalism for expressing classification knowledge and has been used successfully in many diverse areas such as character recognition, medical diagnosis, and expert systems, etc. In order to build a decision tree for vibration diagnosis, we have to define classes and attributes. A set of cases based on past experiences is also needed. This training set is inducted using a result-cause matrix newly developed in the present work instead of using a conventionally implemented cause-result matrix. This method was applied to diagnostics for various cases taken from published work. It is found that the present method predicts causes of the abnormal vibration for test cases with high reliability.

Inverse problem of the vibrational band gap of periodically supported beam

Science.gov (United States)

Shi, Xiaona; Shu, Haisheng; Dong, Fuzhen; Zhao, Lei

2017-04-01

The researches of periodic structures have a long history with the main contents confined in the field of forward problem. In this paper, the inverse problem is considered and an overall frame is proposed which includes two main stages, i.e., the band gap criterion and its optimization. As a preliminary investigation, the inverse problem of the flexural vibrational band gap of a periodically supported beam is analyzed. According to existing knowledge of its forward problem, the band gap criterion is given in implicit form. Then, two cases with three independent parameters, namely the double supported case and the triple one, are studied in detail and the explicit expressions of the feasible domain are constructed by numerical fitting. Finally, the parameter optimization of the double supported case with three variables is conducted using genetic algorithm aiming for the best mean attenuation within specified frequency band.

ΔI = 2 Nuclear Staggering in Superdeformed Rotational Bands

Directory of Open Access Journals (Sweden)

Okasha M. D.

2014-01-01

Full Text Available A four parameters model including collective rotational en ergies to fourth order is ap- plied to reproduce the ∆ I = 2 staggering in transition energies in four selected super deformed rotational bands, namely, 148 Gd (SD6, 194 Hg (SD1, SD2, SD3. The model parameters and the spin of the bandhead have been extracted a ssuming various val- ues to the lowest spin of the bandhead at nearest integer, in o rder to obtain a minimum root mean square deviation between calculated and the exper imental transition energies. This allows us to suggest the spin values for the energy level s which are experimentally unknown. For each band a staggering parameter represent the deviation of the transition energies from a smooth reference has been determined by calc ulating the fourth order derivative of the transition energies at a given spin. The st aggering parameter contains five consecutive transition energies which is denoted here a s the five-point formula. In order to get information about the dynamical moment of ine rtia, the two point for- mula which contains only two consecutive transition energi es has been also considered. The dynamical moment of inertia decreasing with increasing rotational frequency for A ∼ 150, while increasing for A ∼ 190 mass regions.

Vibrational dynamics and band structure of methyl-terminated Ge(111)

Energy Technology Data Exchange (ETDEWEB)

Hund, Zachary M.; Nihill, Kevin J.; Sibener, S. J., E-mail: s-sibener@uchicago.edu [The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E. 57" t" h Street, Chicago, Illinois 60637 (United States); Campi, Davide; Bernasconi, M. [Dipartimento di Scienza dei Materiali, Universita di Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); Wong, Keith T.; Lewis, Nathan S. [Division of Chemistry and Chemical Engineering, Beckman Institute and Kavli Nanoscience Institute, California Institute of Technology, 210 Noyes Laboratory, 127-72, Pasadena, California 91125 (United States); Benedek, G. [Dipartimento di Scienza dei Materiali, Universita di Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); Donostia International Physics Center (DIPC), Universidad del País Vasco (EHU), 20018 Donostia/San Sebastian (Spain)

2015-09-28

A combined synthesis, experiment, and theory approach, using elastic and inelastic helium atom scattering along with ab initio density functional perturbation theory, has been used to investigate the vibrational dynamics and band structure of a recently synthesized organic-functionalized semiconductor interface. Specifically, the thermal properties and lattice dynamics of the underlying Ge(111) semiconductor crystal in the presence of a commensurate (1 × 1) methyl adlayer were defined for atomically flat methylated Ge(111) surfaces. The mean-square atomic displacements were evaluated by analysis of the thermal attenuation of the elastic He diffraction intensities using the Debye-Waller model, revealing an interface with hybrid characteristics. The methyl adlayer vibrational modes are coupled with the Ge(111) substrate, resulting in significantly softer in-plane motion relative to rigid motion in the surface normal. Inelastic helium time-of-flight measurements revealed the excitations of the Rayleigh wave across the surface Brillouin zone, and such measurements were in agreement with the dispersion curves that were produced using density functional perturbation theory. The dispersion relations for H-Ge(111) indicated that a deviation in energy and lineshape for the Rayleigh wave was present along the nearest-neighbor direction. The effects of mass loading, as determined by calculations for CD{sub 3}-Ge(111), as well as by force constants, were less significant than the hybridization between the Rayleigh wave and methyl adlayer librations. The presence of mutually similar hybridization effects for CH{sub 3}-Ge(111) and CH{sub 3}-Si(111) surfaces extends the understanding of the relationship between the vibrational dynamics and the band structure of various semiconductor surfaces that have been functionalized with organic overlayers.

Vibrational dynamics and band structure of methyl-terminated Ge(111)

International Nuclear Information System (INIS)

th Street, Chicago, Illinois 60637 (United States))" data-affiliation=" (The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637 (United States))" >Hund, Zachary M.; th Street, Chicago, Illinois 60637 (United States))" data-affiliation=" (The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637 (United States))" >Nihill, Kevin J.; th Street, Chicago, Illinois 60637 (United States))" data-affiliation=" (The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637 (United States))" >Sibener, S. J.; Campi, Davide; Bernasconi, M.; Wong, Keith T.; Lewis, Nathan S.; Benedek, G.

2015-01-01

A combined synthesis, experiment, and theory approach, using elastic and inelastic helium atom scattering along with ab initio density functional perturbation theory, has been used to investigate the vibrational dynamics and band structure of a recently synthesized organic-functionalized semiconductor interface. Specifically, the thermal properties and lattice dynamics of the underlying Ge(111) semiconductor crystal in the presence of a commensurate (1 × 1) methyl adlayer were defined for atomically flat methylated Ge(111) surfaces. The mean-square atomic displacements were evaluated by analysis of the thermal attenuation of the elastic He diffraction intensities using the Debye-Waller model, revealing an interface with hybrid characteristics. The methyl adlayer vibrational modes are coupled with the Ge(111) substrate, resulting in significantly softer in-plane motion relative to rigid motion in the surface normal. Inelastic helium time-of-flight measurements revealed the excitations of the Rayleigh wave across the surface Brillouin zone, and such measurements were in agreement with the dispersion curves that were produced using density functional perturbation theory. The dispersion relations for H-Ge(111) indicated that a deviation in energy and lineshape for the Rayleigh wave was present along the nearest-neighbor direction. The effects of mass loading, as determined by calculations for CD 3 -Ge(111), as well as by force constants, were less significant than the hybridization between the Rayleigh wave and methyl adlayer librations. The presence of mutually similar hybridization effects for CH 3 -Ge(111) and CH 3 -Si(111) surfaces extends the understanding of the relationship between the vibrational dynamics and the band structure of various semiconductor surfaces that have been functionalized with organic overlayers

Semi-analytical Vibration Characteristics of Rotating Timoshenko Beams Made of Functionally Graded Materials

Directory of Open Access Journals (Sweden)

Farzad Ebrahimia

Full Text Available AbstractFree vibration analysis of rotating functionally graded (FG thick Timoshenko beams is presented. The material properties of FG beam vary along the thickness direction of the constituents according to power law model. Governing equations are derived through Hamilton's principle and they are solved applying differential transform method. The good agreement between the results of this article and those available in literature validated the presented approach. The emphasis is placed on investigating the effect of several beam parameters such as constituent volume fractions, slenderness ratios, rotational speed and hub radius on natural frequencies and mode shapes of the rotating thick FG beam.

Predicting superdeformed rotational band-head spin in A ∼ 190 ...

Indian Academy of Sciences (India)

PACS No. 21.60.−n. 1. Introduction. Superdeformed (SD) nuclei are one of the most challenging and ... like A ∼ 60, 80, 130, 150 and 190 [2,3]. ..... work and the research is progressing to give systematic features of rotational bands of SD.

Molecular rotation-vibration dynamics of low-symmetric hydrate crystal in the terahertz region.

Science.gov (United States)

Fu, Xiaojian; Wu, Hongya; Xi, Xiaoqing; Zhou, Ji

2014-01-16

The rotational and vibrational dynamics of molecules in copper sulfate pentahydrate crystal are investigated with terahertz dielectric spectra. It is shown that the relaxation-like dielectric dispersion in the low frequency region is related to the reorientation of water molecules under the driving of terahertz electric field, whereas the resonant dispersion can be ascribed to lattice vibration. It is also found that, due to the hydrogen-bond effect, the vibrational mode at about 1.83 THz along [-111] direction softens with decreasing temperature, that is, the crystal expands in this direction when cooled. On the contrary, the mode hardens in the direction perpendicular to [-111] during the cooling process. This contributes to the further understanding of the molecular structure and bonding features of hydrate crystals.

Rotational bands on few-particle excitations of very high spin

International Nuclear Information System (INIS)

Andersson, C.G.; Krumlinde, J.; Leander, G.; Szymanski, Z.

1980-01-01

An RPA formalism is developed to investigate the existence and properties of slow collective rotation around a non-symmetry axis, when there already exists a large angular momentum K along the symmetry axis built up by aligned single-particle spins. It is found necessary to distinguish between the collectivity and the repeatability of the rotational excitations. First the formalism is applied to bands on hihg-K isomers in the well-deformed nucleus 176 Hf, where the rotational-model picture is reproduced for intermediate K-values in agreement with experiment. At high K there is a suppression of the collectivity corresponding to the diminishing vector-coupling coefficient of the rotational model, but the repeatability actually improves. The moment of inertia is predicted to remain substantially smaller than the rigid-body value so the bands slope up steeply from the yrast line at spins where pairing effects are gone. A second application is to the initially spherical nucleus 212 Rn, which is believed to acquire an oblate deformation that increases steadily with K due to the oblate shape of the aligned orbitals. In this case the repeatable excitations come higher above the yrast line than in 176 Hf, even at comparable deformations. Some collective states may occur very close to yrast, but these are more like dressed singleparticle excitations. The main differences between the two nuclei studied is interpreted as a general consequence of their different shell structure. (author)

Phononic band gaps and vibrations in one- and two-dimensional mass-spring structures

DEFF Research Database (Denmark)

Jensen, Jakob Søndergaard

2003-01-01

The vibrational response of finite periodic lattice structures subjected to periodic loading is investigated. Special attention is devoted to the response in frequency ranges with gaps in the band structure for the corresponding infinite periodic lattice. The effects of boundaries, viscous dampin...

Nonlinear vibrations analysis of rotating drum-disk coupling structure

Science.gov (United States)

Chaofeng, Li; Boqing, Miao; Qiansheng, Tang; Chenyang, Xi; Bangchun, Wen

2018-04-01

A dynamic model of a coupled rotating drum-disk system with elastic support is developed in this paper. By considering the effects of centrifugal and Coriolis forces as well as rotation-induced hoop stress, the governing differential equation of the drum-disk is derived by Donnell's shell theory. The nonlinear amplitude-frequency characteristics of coupled structure are studied. The results indicate that the natural characteristics of the coupling structure are sensitive to the supporting stiffness of the disk, and the sensitive range is affected by rotating speeds. The circumferential wave numbers can affect the characteristics of the drum-disk structure. If the circumferential wave number n = 1 , the vibration response of the drum keeps a stable value under an unbalanced load of the disk, there is no coupling effect if n ≠ 1 . Under the excitation, the nonlinear hardening characteristics of the forward traveling wave are more evident than that of the backward traveling wave. Moreover, because of the coupling effect of the drum and the disk, the supporting stiffness of the disk has certain effect on the nonlinear characteristics of the forward and backward traveling waves. In addition, small length-radius and thickness-radius ratios have a significant effect on the nonlinear characteristics of the coupled structure, which means nonlinear shell theory should be adopted to design rotating drum's parameter for its specific structural parameters.

Numerical calculation of acoustic radiation from band-vibrating structures via FEM/FAQP method

Directory of Open Access Journals (Sweden)

GAO Honglin

2017-08-01

Full Text Available The Finite Element Method (FEM combined with the Frequency Averaged Quadratic Pressure method (FAQP are used to calculate the acoustic radiation of structures excited in the frequency band. The surface particle velocity of stiffened cylindrical shells under frequency band excitation is calculated using finite element software, the normal vibration velocity is converted from the surface particle velocity to calculate the average energy source (frequency averaged across intensity, frequency averaged across pressure and frequency averaged across velocity, and the FAQP method is used to calculate the average sound pressure level within the bandwidth. The average sound pressure levels are then compared with the bandwidth using finite element and boundary element software, and the results show that FEM combined with FAQP is more suitable for high frequencies and can be used to calculate the average sound pressure level in the 1/3 octave band with good stability, presenting an alternative to applying frequency-by-frequency calculation and the average frequency process. The FEM/FAQP method can be used as a prediction method for calculating acoustic radiation while taking the randomness of vibration at medium and high frequencies into consideration.

Use of piezoelectric actuators in active vibration control of rotating machinery

Science.gov (United States)

Lin, Reng Rong; Palazzolo, Alan B.; Kascak, Albert F.; Montague, Gerald

1990-01-01

Theoretical and test results for the development of piezoelectric-actuator-based active vibration control (AVC) are presented. The evolution of this technology starts with an ideal model of the actuator and progresses to a more sophisticated model where the pushers force the squirrel cage ball bearing supports of a rotating shaft. The piezoelectric pushers consist of a stack of piezoelectric ceramic disks that are arranged on top of one another and connected in parallel electrically. This model consists of a prescribed displacement that is proportional to the input voltage and a spring that represents the stiffness of the stack of piezoelectric disks. System tests were carried out to stabilize the AVC system, verify its effectiveness in controlling vibration, and confirm the theory presented.

An analysis of vibration-rotation lines of OH in the solar infrared spectrum

NARCIS (Netherlands)

Grevesse, N.; Sauval, A.J.; Dishoeck, van E.F.

1984-01-01

High resolution solar spectra have permitted the measurement with great accuracy of equivalent widths of vibration-rotation lines of OH in the X2Pi state near 3-micron wavelength. Using recent theoretical results for the transition probabilities, a solar oxygen abundance of (8.93 + or - 0.02) is

Vibration Signal Forecasting on Rotating Machinery by means of Signal Decomposition and Neurofuzzy Modeling

Directory of Open Access Journals (Sweden)

Daniel Zurita-Millán

2016-01-01

Full Text Available Vibration monitoring plays a key role in the industrial machinery reliability since it allows enhancing the performance of the machinery under supervision through the detection of failure modes. Thus, vibration monitoring schemes that give information regarding future condition, that is, prognosis approaches, are of growing interest for the scientific and industrial communities. This work proposes a vibration signal prognosis methodology, applied to a rotating electromechanical system and its associated kinematic chain. The method combines the adaptability of neurofuzzy modeling with a signal decomposition strategy to model the patterns of the vibrations signal under different fault scenarios. The model tuning is performed by means of Genetic Algorithms along with a correlation based interval selection procedure. The performance and effectiveness of the proposed method are validated experimentally with an electromechanical test bench containing a kinematic chain. The results of the study indicate the suitability of the method for vibration forecasting in complex electromechanical systems and their associated kinematic chains.

Vibration of a rotating shaft on hydrodynamic bearings: multi-scales surface effects

International Nuclear Information System (INIS)

Rebufa, Jocelyn

2016-01-01

The hydrodynamic bearing provides good damping properties in rotating machineries. However, the performances of rotor-bearings systems are highly impacted by nonlinear effects that are difficult to analyze. The rotor dynamics prediction requires advanced models for the flow in the bearings. The surface of the bearings seems to have a strong impact on the lubricant flow, acting on the static and dynamic properties of the rotating parts. This study aims to enhance the simulation of the bearings' surface state effect on the motion of the rotating shaft. The flexible shaft interacts with textured hydrodynamic bearings. Multi-scales homogenization is used in a multi-physics algorithm in order to describe the fluid-structure interaction. Different models are used to account for the cavitation phenomenon in the bearings. Nonlinear harmonic methods allow efficient parametric studies of periodic solutions as well as their stability. Moreover, a test rig has been designed to compare predictions to real measurements. Several textured shaft samples modified with femto-seconds LASER surface texturing are tested. In most cases the experimental study showed similar results than the simulation. Enhancements of the vibration behaviors of the rotor-bearing system have been revealed for certain texturing patterns. The self-excited vibration, also known as 'oil whirl' phenomenon, is stabilized on a wide rotating frequency range. However, the simulation tool does not predict well the enhancements that are observed. Vortices in surface texturing patterns have been revealed numerically with Navier-Stokes equation resolution. These results are opposed to the classical lubrication hypothesis. It is also a possible explanation of the enhancements that are experimentally measured with textured bearings. (author) [fr

Steady flow instability in an annulus with deflectors at rotational vibration

Energy Technology Data Exchange (ETDEWEB)

Kozlov, Nikolai V [Lab. Vibrational Hydromechanics, Perm State-Humanitarian Pedagogical University 24 Sibirskaya av., 614990 Perm (Russian Federation); Pareau, Dominique; Stambouli, Moncef [Lab. Chemical Engineering, CentraleSupélec-Université Paris Saclay, Grande Voie des Vignes, 92295 Châtenay-Malabry (France); Ivantsov, Andrey, E-mail: kozlov.n@icmm.ru [Lab. Computational Hydrodynamics Institute of Continuous Media Mechanics UB RAS1 Acad. Korolev st., 614013 Perm (Russian Federation)

2016-12-15

Experimental study and direct numerical simulation of the dynamics of an isothermal low-viscosity fluid are done in a coaxial gap of a cylindrical container making rotational vibrations relative to its axis. On the inner surface of the outer wall of the container, semicircular deflectors are regularly situated, playing the role of flow activators. As a result of vibrations, the activators oscillate tangentially. In the simulation, a 2D configuration is considered, excluding the end-wall effects. In the experiment, a container with a large aspect ratio is used. Steady streaming is generated in the viscous boundary layers on the activators. On each of the latter, beyond the viscous domain, a symmetric vortices pair is formed. The steady streaming in the annulus has an azimuthal periodicity. With an increase in the vibration intensity, a competition between the vortices occurs, as a result of which one of the vortices (let us call it even) approaches the activator and the other one (odd) rolls away and couples with the vortices from the neighbouring pairs. Streamlines of the odd vortices close on each other, forming a cog-wheel shaped flow that encircles the inner wall. Comparison of the experiment and the simulation reveals an agreement at moderate vibration intensity. (paper)

A Small Fullerene (C{sub 24}) may be the Carrier of the 11.2 μ m Unidentified Infrared Band

Energy Technology Data Exchange (ETDEWEB)

Bernstein, L. S.; Shroll, R. M. [Spectral Sciences, Inc., 4 Fourth Ave., Burlington, MA 01803 (United States); Lynch, D. K. [Thule Scientific, P.O. Box 953, Topanga, CA 90290 (United States); Clark, F. O., E-mail: larry@spectral.com, E-mail: rshroll@spectral.com, E-mail: dave@caltech.edu, E-mail: frank.clark@gmail.com [Wopeco Research, 125 South Great Road, Lincoln, MA 01773 (United States)

2017-02-20

We analyze the spectrum of the 11.2 μ m unidentified infrared band (UIR) from NGC 7027 and identify a small fullerene (C{sub 24}) as a plausible carrier. The blurring effects of lifetime and vibrational anharmonicity broadening obscure the narrower, intrinsic spectral profiles of the UIR band carriers. We use a spectral deconvolution algorithm to remove the blurring, in order to retrieve the intrinsic profile of the UIR band. The shape of the intrinsic profile—a sharp blue peak and an extended red tail—suggests that the UIR band originates from a molecular vibration–rotation band with a blue band head. The fractional area of the band-head feature indicates a spheroidal molecule, implying a nonpolar molecule and precluding rotational emission. Its rotational temperature should be well approximated by that measured for nonpolar molecular hydrogen, ∼825 K for NGC 7027. Using this temperature, and the inferred spherical symmetry, we perform a spectral fit to the intrinsic profile, which results in a rotational constant implying C{sub 24} as the carrier. We show that the spectroscopic parameters derived for NGC 7027 are consistent with the 11.2 μ m UIR bands observed for other objects. We present density functional theory (DFT) calculations for the frequencies and infrared intensities of C{sub 24}. The DFT results are used to predict a spectral energy distribution (SED) originating from absorption of a 5 eV photon, and characterized by an effective vibrational temperature of 930 K. The C{sub 24} SED is consistent with the entire UIR spectrum and is the dominant contributor to the 11.2 and 12.7 μ m bands.

Infrared spectrum of the simplest Criegee intermediate CH2OO at resolution 0.25 cm−1 and new assignments of bands 2ν9 and ν5

International Nuclear Information System (INIS)

Huang, Yu-Hsuan; Li, Jun; Guo, Hua; Lee, Yuan-Pern

2015-01-01

The simplest Criegee intermediate CH 2 OO is important in atmospheric chemistry. It has been detected in the reaction of CH 2 I + O 2 with various spectral methods, including infrared spectroscopy; infrared absorption of CH 2 OO was recorded at resolution 1.0 cm −1 in our laboratory. We have improved our system and recorded the infrared spectrum of CH 2 OO at resolution 0.25 cm −1 with rotational structures partially resolved. Observed vibrational wavenumbers and relative intensities are improved from those of the previous report and agree well with those predicted with quantum-mechanical calculations using the MULTIMODE method on an accurate potential energy surface. Observed rotational structures also agree with the simulated spectra according to theoretical predictions. In addition to derivation of critical vibrational and rotational parameters of the vibrationally excited states to confirm the assignments, the spectrum with improved resolution provides new assignments for bands 2ν 9 at 1234.2 cm −1 and ν 5 at 1213.3 cm −1 ; some hot bands and combination bands are also tentatively assigned

Structure of the lowest excited 0/sup +/ rotational band of /sup 16/O

Energy Technology Data Exchange (ETDEWEB)

Ikebata, Yasuhiko; Suekane, Shota

1983-10-01

The structure of the lowest excited 0/sup +/ rotational band is investigated by using the extended Nilsson model wave functions with angular momentum projection and the B1 interaction, two-body LS-force of the Skyrme type and the Coulomb interaction. The results obtained show good agreement with energy interval in this band.

The structure of rotational bands in alpha-cluster nuclei

Directory of Open Access Journals (Sweden)

Bijker Roelof

2015-01-01

Full Text Available In this contribution, I discuss an algebraic treatment of alpha-cluster nuclei based on the introduction of a spectrum generating algebra for the relative motion of the alpha-clusters. Particular attention is paid to the discrete symmetry of the geometric arrangement of the α-particles, and the consequences for the structure of the rotational bands in the 12C and 16O nuclei.

Rotational-vibrational coupling in the BPS Skyrme model of baryons

Energy Technology Data Exchange (ETDEWEB)

Adam, C.; Naya, C.; Sanchez-Guillen, J. [Departamento de Física de Partículas, Universidad de Santiago de Compostela and Instituto Galego de Física de Altas Enerxias (IGFAE), E-15782 Santiago de Compostela (Spain); Wereszczynski, A. [Institute of Physics, Jagiellonian University, Reymonta 4, Kraków (Poland)

2013-11-04

We calculate the rotational-vibrational spectrum in the BPS Skyrme model for the hedgehog skyrmion with baryon number one. The resulting excitation energies for the nucleon and delta Roper resonances are slightly above their experimental values. Together with the fact that in the standard Skyrme model these excitation energies are significantly lower than the experimental ones, this provides strong evidence for the conjecture that the inclusion of the BPS Skyrme model is required for a successful quantitative description of physical properties of baryons and nuclei.

Monodeuterated methane in the outer solar system. I. Spectroscopic analysis of the bands at 1.55 and 1.95 microns

International Nuclear Information System (INIS)

Lutz, B.L.; de Bergh, C.; Maillard, J.P.

1983-01-01

The analysis of the near-infrared spectrum of monodeuterated methane (CH 3 D) near 6400 cm -1 and 5100 cm -1 is presented as the first of a series of papers dealing with laboratory studies of this molecule and with observational searches for it in outer solar system objects. Three new parallel bands which have locally perturbed upper states connecting with the ground state are identified, and approximate rotational constants are derived. The band centered near 6425 cm -1 and the 9613 A band previously analyzed by Lutz, Danehy, and Ramsay are found to form an apparent vibrational progression with the ν 2 fundamental at 2200 cm -1 , and vibrational assignments of 3ν 2 and 5ν 2 , respectively, are proposed. Detailed comparison of the rotational constants of the states involved is shown to support these assignments

10 μm High-resolution spectrum of trans -acrolein: Rotational analysis of the ν 11 , ν 16 , ν 14 and ν 16 + ν 18 - ν 18 bands

Science.gov (United States)

Xu, Li-Hong; Jiang, Xingjie; Shi, Hongyu; Lees, R. M.; McKellar, A. R. W.; Tokaryk, D. W.; Appadoo, D. R. T.

2011-07-01

High-resolution Fourier transform spectra of trans-acrolein, H 2C dbnd C(H) sbnd C(H) dbnd O, have been recorded in the 10 μm region at both room and cooled temperatures on the modified Bomem DA3.002 at the National Research Council of Canada and the Bruker IFS 125HR spectrometer at the far infrared beam line of the Canadian Light Source in Saskatoon. Vibrational fundamentals analyzed so far include the ν11, ν16 and ν14 bands centered at 911.3, 958.7 and 992.7 cm -1 corresponding respectively to the A' in-plane dbnd CH 2-rocking mode, the A″ out-of-plane dbnd CH 2-wagging mode, and the A″ wagging mode highly mixed between the ⩾C sbnd H vinyl and ⩾C sbnd H formyl groups [Vibrational mode descriptions are based on Y.N. Panchenko, P. Pulay, F. Török, J. Mol. Spectrosc. 34 (1976) 283-289.] As well, the ν16 + ν18 - ν18 hot band centred at 957.6 cm -1 has been analyzed, where ν18 is the low-frequency (157.9 cm -1) A″ ⩾C sbnd C ⪕ torsional mode. The ν11 band is a/ b type while the ν16, ν14 and ν16 + ν18 - ν18 bands are c-type. The assigned transitions of each band have been fitted to a Watson asymmetric rotor Hamiltonian, with ground state parameters fixed to values obtained from rotational analyses in the literature. As well, a combined 3-state fit for ν11, ν16 and ν14 was carried out including Coriolis and Z1 constants which account for J and Δ K interactions. Transition dipole moments have been calculated for each of the fundamentals using the ab initio B3LYP method and 6-311++G ∗∗ basis set. For the A' vibrational modes, we have also evaluated transition dipole a- and b-components in the principal axis system from vibrational displacements and dipole moment derivatives. Our ab initio results predict that the ν11 in-plane dbnd CH 2 rocking mode has an a-type transition strength about three times greater than the b-type, which is consistent with our observations. Our ab initio force field analysis gives vibrational mode

Triply coupled vibrational band gap in a periodic and nonsymmetrical axially loaded thin-walled Bernoulli-Euler beam including the warping effect

International Nuclear Information System (INIS)

Yu Dianlong; Fang Jianyu; Cai Li; Han Xiaoyun; Wen Jihong

2009-01-01

The propagation of triply coupled vibrations in a periodic, nonsymmetrical and axially loaded thin-walled Bernoulli-Euler beam composed of two kinds of materials is investigated with the transfer matrix method. The cross-section of the beam lacks symmetrical axes, and bending vibrations in the two perpendicular directions are coupled with torsional vibrations. Furthermore, the effect of warping stiffness is included. The band structures of the periodic beam, both including and excluding the warping effect, are obtained. The frequency response function of the finite periodic beam is simulated with the finite element method. These simulations show large vibration-based attenuation in the frequency range of the gap, as expected. By comparing the band structure of the beam with plane wave expansion method calculations that are available in the literature, one finds that including the warping effect leads to a more accurate simulation. The effects of warping stiffness and axial force on the band structure are also discussed.

Band structures in a two-dimensional phononic crystal with rotational multiple scatterers

Science.gov (United States)

Song, Ailing; Wang, Xiaopeng; Chen, Tianning; Wan, Lele

2017-03-01

In this paper, the acoustic wave propagation in a two-dimensional phononic crystal composed of rotational multiple scatterers is investigated. The dispersion relationships, the transmission spectra and the acoustic modes are calculated by using finite element method. In contrast to the system composed of square tubes, there exist a low-frequency resonant bandgap and two wide Bragg bandgaps in the proposed structure, and the transmission spectra coincide with band structures. Specially, the first bandgap is based on locally resonant mechanism, and the simulation results agree well with the results of electrical circuit analogy. Additionally, increasing the rotation angle can remarkably influence the band structures due to the transfer of sound pressure between the internal and external cavities in low-order modes, and the redistribution of sound pressure in high-order modes. Wider bandgaps are obtained in arrays composed of finite unit cells with different rotation angles. The analysis results provide a good reference for tuning and obtaining wide bandgaps, and hence exploring the potential applications of the proposed phononic crystal in low-frequency noise insulation.

Rotational laser cooling of vibrationally and translationally cold molecular ions

DEFF Research Database (Denmark)

Staanum, Peter; Højbjerre, Klaus; Skyt, Peter Sandegaard

2010-01-01

Stationary molecules in well-defined internal states are of broad interest for physics and chemistry. In physics, this includes metrology 1, 2, 3 , quantum computing 4, 5 and many-body quantum mechanics 6, 7 , whereas in chemistry, state-prepared molecular targets are of interest for uni......-molecular reactions with coherent light fields 8, 9 , for quantum-state-selected bi-molecular reactions 10, 11, 12 and for astrochemistry 12 . Here, we demonstrate rotational ground-state cooling of vibrationally and translationally cold MgH+ ions, using a laser-cooling scheme based on excitation of a single...

Systematic studies of molecular vibrational anharmonicity and vibration-rotation interaction by self-consistent-field higher derivative methods: Applications to asymmetric and symmetric top and linear polyatomic molecules

International Nuclear Information System (INIS)

Clabo, D.A. Jr.

1987-04-01

Inclusion of the anharmonicity normal mode vibrations [i.e., the third and fourth (and higher) derivatives of a molecular Born-Oppenheimer potential energy surface] is necessary in order to theoretically reproduce experimental fundamental vibrational frequencies of a molecule. Although ab initio determinations of harmonic vibrational frequencies may give errors of only a few percent by the inclusion of electron correlation within a large basis set for small molecules, in general, molecular fundamental vibrational frequencies are more often available from high resolution vibration-rotation spectra. Recently developed analytic third derivatives methods for self-consistent-field (SCF) wavefunctions have made it possible to examine with previously unavailable accuracy and computational efficiency the anharmonic force fields of small molecules

Systematic studies of molecular vibrational anharmonicity and vibration-rotation interaction by self-consistent-field higher derivative methods: Applications to asymmetric and symmetric top and linear polyatomic molecules

Energy Technology Data Exchange (ETDEWEB)

Clabo, D.A. Jr.

1987-04-01

Inclusion of the anharmonicity normal mode vibrations (i.e., the third and fourth (and higher) derivatives of a molecular Born-Oppenheimer potential energy surface) is necessary in order to theoretically reproduce experimental fundamental vibrational frequencies of a molecule. Although ab initio determinations of harmonic vibrational frequencies may give errors of only a few percent by the inclusion of electron correlation within a large basis set for small molecules, in general, molecular fundamental vibrational frequencies are more often available from high resolution vibration-rotation spectra. Recently developed analytic third derivatives methods for self-consistent-field (SCF) wavefunctions have made it possible to examine with previously unavailable accuracy and computational efficiency the anharmonic force fields of small molecules.

Microscopic study of superdeformed rotational bands in {sup 151} Tb

Energy Technology Data Exchange (ETDEWEB)

El Aouad, N.; Dudek, J.; Li, X.; Luo, W.D.; Molique, H.; Bouguettoucha, A.; Byrski, TH.; Beck, F.; Finck, C.; Kharraja, B. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Dobaczewski, J. [Warsaw Univ. (Poland); Kharraja, B. [Notre Dame Univ., IN (United States). Dept. of Physics

1996-12-31

Structure of eight superdeformed bands in the nucleus {sup 151}Tb is analyzed using the results of the Hartree-Fock and Woods-Saxon cranking approaches. It is demonstrated that far going similarities between the two approaches exit and predictions related to the structure of rotational bands calculated within the two models are nearly parallel. An interpretation scenario for the structure of the superdeformed bands is presented and predictions related to the exit spins are made. Small but systematic discrepancies between experiment and theory, analyzed in terms of the dynamical moments, J{sup (2)}, are shown to exist. The pairing correlations taken into account by using the particle-number-projection technique are shown to increase the disagreement. Sources of these systematic discrepancies are discussed - they are most likely related to the yet not optimal parametrization of the nuclear interactions used. (authors). 60 refs.

The effect of gas and fluid flows on nonlinear lateral vibrations of rotating drill strings

Science.gov (United States)

Khajiyeva, Lelya; Kudaibergenov, Askar; Kudaibergenov, Askat

2018-06-01

In this work we develop nonlinear mathematical models describing coupled lateral vibrations of a rotating drill string under the effect of external supersonic gas and internal fluid flows. An axial compressive load and a torque also affect the drill string. The mathematical models are derived by the use of Novozhilov's nonlinear theory of elasticity with implementation of Hamilton's variation principle. Expressions for the gas flow pressure are determined according to the piston theory. The fluid flow is considered as added mass inside the curved tube of the drill string. Using an algorithm developed in the Mathematica computation program on the basis of the Galerkin approach and the stiffness switching method the numerical solution of the obtained approximate differential equations is found. Influences of the external loads, drill string angular speed of rotation, parameters of the gas and fluid flows on the drill string vibrations are shown.

A novel vibration-based fault diagnostic algorithm for gearboxes under speed fluctuations without rotational speed measurement

Science.gov (United States)

Hong, Liu; Qu, Yongzhi; Dhupia, Jaspreet Singh; Sheng, Shuangwen; Tan, Yuegang; Zhou, Zude

2017-09-01

The localized failures of gears introduce cyclic-transient impulses in the measured gearbox vibration signals. These impulses are usually identified from the sidebands around gear-mesh harmonics through the spectral analysis of cyclo-stationary signals. However, in practice, several high-powered applications of gearboxes like wind turbines are intrinsically characterized by nonstationary processes that blur the measured vibration spectra of a gearbox and deteriorate the efficacy of spectral diagnostic methods. Although order-tracking techniques have been proposed to improve the performance of spectral diagnosis for nonstationary signals measured in such applications, the required hardware for the measurement of rotational speed of these machines is often unavailable in industrial settings. Moreover, existing tacho-less order-tracking approaches are usually limited by the high time-frequency resolution requirement, which is a prerequisite for the precise estimation of the instantaneous frequency. To address such issues, a novel fault-signature enhancement algorithm is proposed that can alleviate the spectral smearing without the need of rotational speed measurement. This proposed tacho-less diagnostic technique resamples the measured acceleration signal of the gearbox based on the optimal warping path evaluated from the fast dynamic time-warping algorithm, which aligns a filtered shaft rotational harmonic signal with respect to a reference signal assuming a constant shaft rotational speed estimated from the approximation of operational speed. The effectiveness of this method is validated using both simulated signals from a fixed-axis gear pair under nonstationary conditions and experimental measurements from a 750-kW planetary wind turbine gearbox on a dynamometer test rig. The results demonstrate that the proposed algorithm can identify fault information from typical gearbox vibration measurements carried out in a resource-constrained industrial environment.

Spin alignment and collective moment of inertia of the basic rotational band in the cranking model

International Nuclear Information System (INIS)

Tanaka, Yoshihide

1982-01-01

By making an attempt to separate the intrinsic particle and collective rotational motions in the cranking model, the spin alignment and the collective moment of inertia characterizing the basic rotational bands are defined, and are investigated by using a simple i sub(13/2) shell model. The result of the calculation indicates that the collective moment of inertia decreases under the presence of the quasiparticles which are responsible for the increase of the spin alignment of the band. (author)

High resolution emission Fourier transform infrared spectra of the 4p-5s and 5p-6s bands of ArH.

Science.gov (United States)

Baskakov, O I; Civis, S; Kawaguchi, K

2005-03-15

In the 2500-8500 cm(-1) region several strong emission bands of (40)ArH were observed by Fourier transform spectroscopy through a dc glow discharge in a mixture of argon and hydrogen. Rotational-electronic transitions of the two previously unstudied 4p-5s and 5p-6s,v = 0-0, bands of (40)ArH were measured and assigned in the 6060 and 3770 cm(-1) regions, respectively. A simultaneous fit of the emission transitions of the 4p-5s and 5p-6s bands and an extended set of transitions of the 6s-4p band observed by Dabrowski, Tokaryk, and Watson [J. Mol. Spectrosc. 189, 95 (1998)] and remeasured in the present work yielded consistent values of the spectroscopic parameters of the electronic states under investigation. In the branch of the 4p-5s band with transitions of type (Q)Q(f(3)e) we observed a narrowing in the linewidths with increasing rotational quantum number N. The rotational dependence of the linewidth is caused by predissociation of the 5s state by the repulsive ground 4s state through homogeneous coupling and changes in overlap integrals of the vibrational wave functions with the rotational level. Analysis was based on the Fermi's golden rule approximation model. In the 4p-5s band region a vibrational sequence ofv(')-v(")=1-1, 2-2, and 3-3 were recorded and a number of transitions belonging to the strongest (Q)Q(f(3)e) form branch of the 1-1 band were analyzed.

Signature splitting in nuclear rotational bands: Neutron i13/2 systematics

International Nuclear Information System (INIS)

Mueller, W.F.; Jensen, H.J.; Reviol, W.; Riedinger, L.L.; Yu, C.; Zhang, J.; Nazarewicz, W.; Wyss, R.

1994-01-01

Experimental values of signature splitting in νi 13/2 rotational bands in odd-N even-Z nuclei in the Z=62--78 region are collected and presented. A procedure is introduced to calculate signature splitting within the cranked deformed Woods-Saxon model. In the theoretical treatment, deformation parameters are obtained by minimizing the total Routhians of individual νi 13/2 bands, and the procedure accounts for the possibility that the two signatures have different deformations and pairing gaps. Experimental signature splitting data for νi 13/2 bands in Dy, Er, Yb, Hf, W, and Os nuclei are compared with calculated values. The sensitivity of calculated signature splitting to changes in deformation, pairing, and other model parameters is presented

Image-based tracking system for vibration measurement of a rotating object using a laser scanning vibrometer

Energy Technology Data Exchange (ETDEWEB)

Kim, Dongkyu, E-mail: akein@gist.ac.kr; Khalil, Hossam; Jo, Youngjoon; Park, Kyihwan, E-mail: khpark@gist.ac.kr [School of Mechatronics, Gwangju Institute of Science and Technology, Buk-gu, Gwangju, South Korea, 500-712 (Korea, Republic of)

2016-06-28

An image-based tracking system using laser scanning vibrometer is developed for vibration measurement of a rotating object. The proposed system unlike a conventional one can be used where the position or velocity sensor such as an encoder cannot be attached to an object. An image processing algorithm is introduced to detect a landmark and laser beam based on their colors. Then, through using feedback control system, the laser beam can track a rotating object.

Comparative analysis of the vibrational structure of the absorption spectra of acrolein in the excited ( S 1) electronic state

Science.gov (United States)

Koroleva, L. A.; Tyulin, V. I.; Matveev, V. K.; Pentin, Yu. A.

2012-04-01

The assignments of absorption bands of the vibrational structure of the UV spectrum are compared with the assignments of bands obtained by the CRDS method in a supersonic jet from the time of laser radiation damping for the trans isomer of acrolein in the excited ( S 1) electronic state. The ν00 trans = 25861 cm-1 values and fundamental frequencies, including torsional vibration frequency, obtained by the two methods were found to coincide in the excited electronic state ( S 1) for this isomer. The assignments of several absorption bands of the vibrational structure of the spectrum obtained by the CRDS method were changed. Changes in the assignment of (0-v') transition bands of the torsional vibration of the trans isomer in the Deslandres table from the ν00 trans trans origin allowed the table to be extended to high quantum numbers v'. The torsional vibration frequencies up to v' = 5 were found to be close to the frequencies found by analyzing the vibrational structure of the UV spectrum and calculated quantum-mechanically. The coincidence of the barrier to internal rotation (the cis-trans transition) in the one-dimensional model with that calculated quantum-mechanically using the two-dimensional model corresponds to a planar structure of the acrolein molecule in the excited ( S 1) electronic state.

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

Spin, quadrupole moment, and deformation of the magnetic-rotational band head in Pb193

Science.gov (United States)

Balabanski, D. L.; Ionescu-Bujor, M.; Iordachescu, A.; Bazzacco, D.; Brandolini, F.; Bucurescu, D.; Chmel, S.; Danchev, M.; de Poli, M.; Georgiev, G.; Haas, H.; Hübel, H.; Marginean, N.; Menegazzo, R.; Neyens, G.; Pavan, P.; Rossi Alvarez, C.; Ur, C. A.; Vyvey, K.; Frauendorf, S.

2011-01-01

The spectroscopic quadrupole moment of the T1/2=9.4(5) ns isomer in Pb193 at an excitation energy Eex=(2585+x) keV is measured by the time-differential perturbed angular distribution method as |Qs|=2.6(3) e b. Spin and parity Iπ=27/2- are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the 1i13/2 subshell with the (3s1/2-21h9/21i13/2)11- proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation ɛ2=-0.11, similar to that of the 11-proton intruder states, which nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.

Commutator perturbation method in the study of vibrational-rotational spectra of diatomic molecules

International Nuclear Information System (INIS)

Matamala-Vasquez, A.; Karwowski, J.

2000-01-01

The commutator perturbation method, an algebraic version of the Van Vleck-Primas perturbation method, expressed in terms of ladder operators, has been applied to solving the eigenvalue problem of the Hamiltonian describing the vibrational-rotational motion of a diatomic molecule. The physical model used in this work is based on Dunham's approach. The method facilitates obtaining both energies and eigenvectors in an algebraic way

VCD Robustness of the Amide-I and Amide-II Vibrational Modes of Small Peptide Models.

Science.gov (United States)

Góbi, Sándor; Magyarfalvi, Gábor; Tarczay, György

2015-09-01

The rotational strengths and the robustness values of amide-I and amide-II vibrational modes of For(AA)n NHMe (where AA is Val, Asn, Asp, or Cys, n = 1-5 for Val and Asn; n = 1 for Asp and Cys) model peptides with α-helix and β-sheet backbone conformations were computed by density functional methods. The robustness results verify empirical rules drawn from experiments and from computed rotational strengths linking amide-I and amide-II patterns in the vibrational circular dichroism (VCD) spectra of peptides with their backbone structures. For peptides with at least three residues (n ≥ 3) these characteristic patterns from coupled amide vibrational modes have robust signatures. For shorter peptide models many vibrational modes are nonrobust, and the robust modes can be dependent on the residues or on their side chain conformations in addition to backbone conformations. These robust VCD bands, however, provide information for the detailed structural analysis of these smaller systems. © 2015 Wiley Periodicals, Inc.

Vibration suppression of a rotating flexible cantilever pipe conveying fluid using piezoelectric layers

Directory of Open Access Journals (Sweden)

S. Khajehpour

Full Text Available AbstractIn this study, the governing equations of a rotating cantilever pipe conveying fluid are derived and the longitudinal and lateral induced vibrations are controlled. The pipe considered as an Euler Bernoulli beam with tip mass which piezoelectric layers attached both side of it as sensors and actuators. The follower force due to the fluid discharge causes both conservative and non-conservative work. For mathematical modeling, the Lagrange-Rayleigh-Ritz technique is utilized. An adaptive-robust control scheme is applied to suppress the vibration of the pipe. The adaptive-robust control method is robust against parameter uncertainties and disturbances. Finally, the system is simulated and the effects of varying parameters are studied. The simulation results show the excellent performance of the controller.

Rovibrational Interaction and Vibrational Constants of the Symmetric Top Molecule 14NF3

Directory of Open Access Journals (Sweden)

Hamid Najib

2013-01-01

Full Text Available Several accurate experimental values of the and rotation-vibration interaction parameters and , , and vibrational constants have been extracted from the most recent high-resolution Fourier transform infrared, millimeter wave, and centimeter wave investigations in the spectra of the oblate symmetric top molecule 14NF3. The band-centres used are those of the four fundamental, the overtones, the combination, and hot bands identified in the region between 400 cm−1 and 2000 cm−1. Comparison of our constants with the ones measured previously, by infrared spectroscopy at low resolution, reveals orders of magnitude higher accuracy of the new values. The agreement between our values and those determined by ab initio calculations employing the TZ2Pf basis is excellent.

Determining rotational temperatures from the OH(8-3 band, and a comparison with OH(6-2 rotational temperatures at Davis, Antarctica

Directory of Open Access Journals (Sweden)

F. Phillips

2004-04-01

Full Text Available Rotational temperatures derived from the OH(8–3 band may vary by ~18K depending on the choice of transition probabilities. This is of concern when absolute temperatures or trends determined in combination with measurements of other hydroxyl bands are important. In this paper, measurements of the OH(8–3 temperature-insensitive Q/P and R/P line intensity ratios are used to select the most appropriate transition probabilities for use with this band. Aurora, airglow and solar and telluric absorption in the OH(8–3 band are also investigated. Water vapour absorption of P₁(4, airglow or auroral contamination of P₁(2 and solar absorption in the vicinity of P₁(5 are concerns to be considered when deriving rotational temperatures from this band.

A comparison is made of temperatures derived from OH(6–2 and OH(8–3 spectra collected alternately at Davis (69° S, 78° E in 1990. An average difference of ~4K is found, with OH(8–3 temperatures being warmer, but a difference of this magnitude is within the two sigma uncertainty limit of the measurements.

Key words. Atmospheric composition and structure airglow and aurora; pressure, density, and temperature

Vibration analysis of rotating nanobeam systems using Eringen's two-phase local/nonlocal model

Science.gov (United States)

Khaniki, Hossein Bakhshi

2018-05-01

Due to the inability of differential form of nonlocal elastic theory in modelling cantilever beams and inaccurate results for some type of boundaries, in this study, a reliable investigation on transverse vibrational behavior of rotating cantilever size-dependent beams is presented. Governing higher order equations are written in the framework of Eringen's two-phase local/nonlocal model and solved using a modified generalized differential quadrature method. In order to indicate the influence of different material and scale parameters, a comprehensive parametric study is presented. It is shown that increasing the nonlocality term leads to lower natural frequency terms for cantilever nanobeams especially for the fundamental frequency parameter which differential nonlocal model is unable to track appropriately. Moreover, it is shown that rotating speed and hub radius have a remarkable effect in varying the mechanical behavior of rotating cantilever nanobeams. This study is a step forward in analyzing nanorotors, nanoturbines, nanoblades, etc.

Ground-state and pairing-vibrational bands with equal quadrupole collectivity in 124Xe

Science.gov (United States)

Radich, A. J.; Garrett, P. E.; Allmond, J. M.; Andreoiu, C.; Ball, G. C.; Bianco, L.; Bildstein, V.; Chagnon-Lessard, S.; Cross, D. S.; Demand, G. A.; Diaz Varela, A.; Dunlop, R.; Finlay, P.; Garnsworthy, A. B.; Hackman, G.; Hadinia, B.; Jigmeddorj, B.; Laffoley, A. T.; Leach, K. G.; Michetti-Wilson, J.; Orce, J. N.; Rajabali, M. M.; Rand, E. T.; Starosta, K.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Wang, Z. M.; Wood, J. L.; Wong, J.; Williams, S. J.; Yates, S. W.

2015-04-01

The nuclear structure of 124Xe has been investigated via measurements of the β+/EC decay of 124Cs with the 8 π γ -ray spectrometer at the TRIUMF-ISAC facility. The data collected have enabled branching ratio measurements of weak, low-energy transitions from highly excited states, and the 2+→0+ in-band transitions have been observed. Combining these results with those from a previous Coulomb excitation study, B (E 2 ;23+→02+) =78 (13 ) W.u. and B (E 2 ;24+→03+) =53 (12 ) W.u. were determined. The 03+ state, in particular, is interpreted as the main fragment of the proton-pairing vibrational band identified in a previous 122Te (3He,n )124Xe measurement, and has quadrupole collectivity equal to, within uncertainty, that of the ground-state band.

Band shape of IR-absorption of complex molecules and restricted rotational diffusion

International Nuclear Information System (INIS)

Ivanov, E.N.; Umidulaev, Sh.U.

1989-01-01

The development of the theory of band shape (and Breadth) IR-absorption of complex molecules (regarding the molecules inside motions) is considered. It is supposed that a molecule fragment being responsible for IR-absorption takes part in the restricted rotational diffusion (RRD) with respect to the frame, and the molecule itself in general makes rotational motion (RM). Both kinds of motions are discussed in accordance with the theory of group motions representations. On the basis of correlative functions calculations of dipole moment a simple expression for the IR-absorption band shape have been obtained, which in itself uses to be the super position of two Lorencians with the semibreadths 2D 1 and 2D 1 +ν 2 0 (ν 2 0 +1D R accordingly (here D 1 is the coefficient of RM, D 2 is the coefficient of RRD, ν 2 0 is the well known function of RRD-cone divergence angle) in case of symmetric rotary abrasive disc. Analysis of experimental band shape of IR-absorption on the basis of the expression obtained allows to get information of MR-molecule parameters in general and RRD. It is really possible to determine the RRD-cone divergency angle from experimental weights of Lorencians. In accordance with experimental semibreadths the coefficient of RM D 1 and the coefficient of RRD D 2 are obtained. In conclusion it is noted that D 1 →0 (in the expression for the band shape of IR-absorption obtained), one of the Lorencians turns to the δ-function and finally there is an expression which describes IR-absorption band shape of molecules in polymer-mats. (author)

Intrinsic states and rotational bands in 177Pt

International Nuclear Information System (INIS)

Dracoulis, G.D.; Fabricius, B.; Bark, R.A.; Stuchbery, A.E.; Popescu, D.G.; Kibedi, T.

1989-11-01

The 149 Sm ( 32 S,4n) 177 Pt reaction has been used to populate excited states in the neutron-deficient nucleus 177 Pt. Rotational bands based on intrinsic states assigned to the 1/2-[521], 5/2-[521] and (mixed) 7/2+ [633] Nilsson configurations have been observed. In contrast to the neighbou-ring even isotope 176 Pt, anomalies attributed to shape co-existence at low spin have not been observed. Implications for the deformation of 177 Pt are discussed together with the systematics of intrinsic states in this region, and alignments and other properties of N=99 nuclei. 37 refs., 15 figs., 3 tabs

A study on the annular leakage-flow-induced vibrations. 1st report. Stability for translational and rotational single-degree-of-freedom systems

International Nuclear Information System (INIS)

Li, Dong-Wei; Kaneko, Shigehiko; Hayama, Shinji

1999-01-01

This study reports the stability of annular leakage-flow-induced vibrations. The pressure distribution of fluid between a fixed outer cylinder and a vibrating inner cylinder was obtained in the case of a translationally and rotationally coupled motion of the inner cylinder. The unsteady fluid force acting on the inner cylinder in the case of translational and rotational single-degree-of-freedom vibrations was then expressed in terms proportional to the acceleration, velocity, and displacement. Then the critical flow rate (at which stability was lost) was determined for an annular leakage-flow-induced vibration. Finally, the stability was investigated theoretically. It is known that instability will occur in the case of a divergent passage, but the critical flow rate depends on the passage increment in a limited range: the eccentricity of the passage and the pressure loss factor at the inlet of the passage lower the stability. (author)

Fragmentation of two-phonon {gamma}-vibrational strength in deformed nuclei

Energy Technology Data Exchange (ETDEWEB)

Wu, C.Y.; Cline, D. [Univ. of Rochester, NY (United States)

1996-12-31

Rotational and vibrational modes of collective motion. are very useful in classifying the low-lying excited states in deformed nuclei. The rotational mode of collective motion is characterized by rotational bands having correlated level energies and strongly-enhanced E2 matrix elements. The lowest intrinsic excitation with I,K{sup {pi}} = 2,2{sup +} in even-even deformed nuclei, typically occurring at {approx}1 MeV, is classified as a one-phonon {gamma}-vibration state. In a pure harmonic vibration limit, the expected two-phonon {gamma}-vibration states with I,K{sup {pi}} = 0,0{sup +} and 4,4{sup +} should have excitation energies at twice that of the I,K{sup {pi}} = 2,2{sup +} excitation, i.e. {approx}2 MeV, which usually is above the pairing gap leading to possible mixing with two-quasiparticle configurations. Therefore, the question of the localization of two-phonon {gamma}-vibration strength has been raised because mixing may lead to fragmentation of the two-phonon strength over a range of excitation energy. For several well-deformed nuclei, an assignment of I,K{sup {pi}}=4,4{sup +} states as being two-phonon vibrational excitations has been suggested based on the excitation energies and the predominant {gamma}-ray decay to the I,K{sup {pi}}=2,2{sup +} state. However, absolute B(E2) values connecting the presumed two- and one-phonon states are the only unambiguous measure of double phonon excitation. Such B(E2) data are available for {sup 156}Gd, {sup 160}Dy, {sup 168}Er, {sup 232}Th, and {sup 186,188,190,192}Os. Except for {sup 160}Dy, the measured B(E2) values range from 2-3 Weisskopf units in {sup 156}Gd to 10-20 Weisskopf units in osmium nuclei; enhancement that is consistent with collective modes of motion.

Raman polarizabilities of the ν2, ν5 bands of CD3Cl

International Nuclear Information System (INIS)

Escribano, R.; Hernandez, M.G.; Mejias, M.; Brodersen, S.

1985-01-01

The Raman spectrum of the Coriolis interacting ν 2 , ν 5 bands of CD 3 Cl was recorded with a resolution of ca 0.6 cm -1 . Using the vibrational-rotational parameters of Yamada and Hirota, a computer simulation of the Raman contour was performed, yielding relative values of Raman polarizability derivatives for these bands. By comparison with the absolute intensity measurement of Orza et al., absolute values of the Raman polarizabilities were obtained. The sign of the Raman intensity perturbation was found to be negative. (author)

Spin, quadrupole moment, and deformation of the magnetic-rotational band head in (193)Pb

CERN Document Server

Balabanski, D L; Iordachescu, A; Bazzacco, D; Brandolini, F; Bucurescu, D; Chmel, S; Danchev, M; De Poli, M; Georgiev, G; Haas, H; Hubel, H; Marginean, N; Menegazzo, R; Neyens, G; Pavan, P; Rossi Alvarez, C; Ur, C A; Vyvey, K; Frauendorf, S

2011-01-01

The spectroscopic quadrupole moment of the T(1/2) = 9.4(5) ns isomer in (193)Pb at an excitation energy E(ex) = (2585 + x) keV is measured by the time-differential perturbed angular distribution method as vertical bar Q(s)vertical bar = 2.6(3) e b. Spin and parity I(pi) = 27/2(-) are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the coupling of a neutron hole in the 1i(13/2) subshell with the (3s(1/2)(-2)1h(9/2)1i(13/2))(11-) proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation epsilon(2) = -0.11, similar to that of the 11(-)proton intruder states, which occur in the even-even Pb nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.

Hyperfine-resolved transition frequency list of fundamental vibration bands of H35Cl and H37Cl

Science.gov (United States)

Iwakuni, Kana; Sera, Hideyuki; Abe, Masashi; Sasada, Hiroyuki

2014-12-01

Sub-Doppler resolution spectroscopy of the fundamental vibration bands of H35Cl and H37Cl has been carried out from 87.1 to 89.9 THz. We have determined the absolute transition frequencies of the hyperfine-resolved R(0) to R(4) transitions with a typical uncertainty of 10 kHz. We have also yielded six molecular constants for each isotopomer in the vibrational excited state, which reproduce the determined frequencies with a standard deviation of about 10 kHz.

Design and Experimental Characterization of a Vibration Energy Harvesting Device for Rotational Systems

Directory of Open Access Journals (Sweden)

Lutao Yan

2013-01-01

Full Text Available This paper presents a new vibration based electromagnetic power generator to transfer energy from stationary to rotating equipment, which can be a new attempt to substitute slip ring in rotational systems. The natural frequencies and modes are simulated in order to have a maximum and steady power output from the device. Parameters such as piezoelectric disk location and relative motion direction of the magnet are theoretically and experimentally analyzed. The results show that the position that is close to the fixed end of the cantilever and the relative motion along the long side gives higher power output. Moreover, the capability of the energy harvester to extract power from lower energy environment is experimentally validated. The voltage and power output are measured at different excitation frequencies.

Search for the characters of chiral rotation in excited bands for the idea chiral nuclei with A ∼ 130

International Nuclear Information System (INIS)

Chen Qibo; Yao Jiangming; Meng Jie; Zhang Shuangquan; Qi Bin

2010-01-01

Since the occurrence of chirality was originally suggested in 1997 by Frauendorf and Meng [1] and experimentally observed in 2001 [2] , the investigation of chiral symmetry in atomic nuclei becomes one of the most important topics in nuclear physics. More and more chiral doublet bands [3-7] in atomic nuclei [8] have been reported. There are also many discussions about the fingerprints of chirality. In the pioneer paper [1] , the two lowest near degenerate bands given by the particle-rotor model (PRM) are interpreted as chiral doublet bands. If the nucleus has chiral geometry with proper configuration, the character of chiral rotation may appear not only in the two lowest bands, but also in the other bands. Therefore, it is interesting to search for the character of chiral rotation, Based on the PRM model with configuration corresponding to A ∼ 130 mass region, we examine the theoretical spectroscopy of higher excited bands (band3, band4, band5 and band6) beyond the two lowest bands (bandl and band2), including energies, spin-alignments, projection of total angular momentum and electromagnetic transition probabilities. The results show that band3 and band4 have characters of chirality in some spin region. (authors)

Broad-band linear polarization and magnetic intensification in rotating magnetic stars

International Nuclear Information System (INIS)

Degl'Innocenti, M.L.; Calamai, G.; Degl'Innocenti, E.L.; Patriarchi, P.

1981-01-01

Magnetic intensification is proposed as a mechanism to explain the general features of the variable broad-band linear polarization emerging from rotating magnetic stars. This mechanism is studied in detail, and some efforts are made to investigate the wide variety of polarization diagrams that can result from it. Theoretical results are compared with direct observations of the variable magnetic star 53 Cam to determine its geometric and magnetic configuration

An Unusual Rotationally Modulated Attenuation Band in the Jovian Hectometric Radio Emission Spectrum

Science.gov (United States)

Gurnett, D. A.; Kurth, W. S.; Menietti, J. D.; Persoon, A. M.

1998-01-01

A well-defined attenuation band modulated by the rotation of Jupiter has been found in the spectrum of Jovian hectometric radiation using data from the Galileo plasma wave instrument. The center frequency of this band usually occurs in the frequency range from about 1 to 3 MHz and the bandwidth is about 10 to 20 percent. The center frequency varies systematically with the rotation of Jupiter and has two peaks per rotation, the first at a system III longitude of about 50 deg, and the second at about 185 deg. It is now believed that the attenuation occurs as the ray path from a high-latitude cyclotron maser source passes approximately parallel to the magnetic field near the northern or southern edges of the Io L-shell. The peak at 50 deg system 3 longitude is attributed to radiation from a southern hemisphere source and the peak at 185 deg is from a northern hemisphere source. The attenuation is thought to be caused by coherent scattering or shallow angle reflection from field-aligned density irregularities near the Io L-shell. The narrow bandwidth indicates that the density irregularities are confined to a very narrow range of L values (Delta L = 0.2 to 0.4) near the Io L-shell.

Rotational bands terminating at maximal spin in the valence space

Energy Technology Data Exchange (ETDEWEB)

Ragnarsson, I.; Afanasjev, A.V. [Lund Institute of Technology (Sweden)

1996-12-31

For nuclei with mass A {le} 120, the spin available in {open_quotes}normal deformation configurations{close_quotes} is experimentally accessible with present detector systems. Of special interest are the nuclei which show collective features at low or medium-high spin and where the corresponding rotational bands with increasing spin can be followed in a continuous way to or close to a non-collective terminating state. Some specific features in this context are discussed for nuclei in the A = 80 region and for {sup 117,118}Xe.

ExoMol molecular line lists - XVII. The rotation-vibration spectrum of hot SO₃

DEFF Research Database (Denmark)

Underwood, Daniel S.; Yurchenko, Sergei N.; Tennyson, Jonathan

2016-01-01

Sulphur trioxide (SO3) is a trace species in the atmospheres of the Earth and Venus, as well as being an industrial product and an environmental pollutant. A variational line list for 32S16O3, named UYT2, is presented containing 21 billion vibration-rotation transitions. UYT2 can be used to model...

Prediction of absolute infrared intensities for the fundamental vibrations of H2O2

Science.gov (United States)

Rogers, J. D.; Hillman, J. J.

1981-01-01

Absolute infrared intensities are predicted for the vibrational bands of gas-phase H2O2 by the use of a hydrogen atomic polar tensor transferred from the hydroxyl hydrogen atom of CH3OH. These predicted intensities are compared with intensities predicted by the use of a hydrogen atomic polar tensor transferred from H2O. The predicted relative intensities agree well with published spectra of gas-phase H2O2, and the predicted absolute intensities are expected to be accurate to within at least a factor of two. Among the vibrational degrees of freedom, the antisymmetric O-H bending mode nu(6) is found to be the strongest with a calculated intensity of 60.5 km/mole. The torsional band, a consequence of hindered rotation, is found to be the most intense fundamental with a predicted intensity of 120 km/mole. These results are compared with the recent absolute intensity determinations for the nu(6) band.

Rotational band structure in 132La

International Nuclear Information System (INIS)

Oliveira, J.R.B.; Emediato, L.G.R.; Rizzutto, M.A.; Ribas, R.V.; Seale, W.A.; Rao, M.N.; Medina, N.H.; Botelho, S.; Cybulska, E.W.

1989-01-01

'3'2La was studied using on-line gamma-spectroscopy through the reactions '1 24,126 Te( 11,10 B, 3, 4n) 132 La. The excitation function was obtained with 10 B(E lab =41.4; 45.4 and 48 MeV) in order to identify 132 La gamma-transitions. Gamma-gamma coincidences and angular distributions were performed for the 126 Te( 10 B, 4n) 132 La reaction. From the experimental results a rotational band with strongest M1 transitions and less intense 'cross-overs' E2 transitions was constructed. Using the methods of Bengtsson and Frauendorf the alignment (ix) and the Routhian (e') as a function of the angular velocity (ω) were also obtained from the experimental data. It was observed a constant alignment up to ω≅0.4 MeV, and a signature-splitting Δe'=25keV. Preliminary triaxial Cranking-Shell Model calculations indicate that a γ=-8deg deformation is consistent with the signature-splitting value of 25 keV experimentally observed. (Author) [es

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.

Comparison between the harris and ab expressions for the description of nuclear superdeformed rotational bands

International Nuclear Information System (INIS)

Hu Zuoxian; Zeng Jinyan

1998-01-01

The superdeformed rotational bands in the A ≅3D 190 region are systematically analyzed using the Harris two-parameter formula and the ab expression, respectively. Similar to the situations in normally deformed nuclei, there exist obvious and systematic deviation of Harris formula from the experiments. In contrast, the prediction of ab formula is very close to experiments, and can be conveniently used for the description of nuclear superdeformed bands

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.

Folding-type coupling potentials in the context of the generalized rotation-vibration model

Science.gov (United States)

Chamon, L. C.; Morales Botero, D. F.

2018-03-01

The generalized rotation-vibration model was proposed in previous works to describe the structure of heavy nuclei. The model was successfully tested in the description of experimental results related to the electron-nucleus elastic and inelastic scattering. In the present work, we consider heavy-ion collisions and assume this model to calculate folding-type coupling potentials for inelastic states, through the corresponding transition densities. As an example, the method is applied to coupled-channel data analyses for the α + 70,72,74,76Ge systems.

Polarization labelling spectroscopy of the A 1Σ+sub(u) band of Na2

International Nuclear Information System (INIS)

Itoh, H.; Hayakawa, M.; Fukuda, Y.; Matsuoka, M.

1981-01-01

A result of the polarization labelling spectroscopy of the A 1 Σ + sub(u) band of sodium dimer for the high vibrational quantum number upsilon' > 20 is reported. The frequency difference Δν = νsub(o)sub(b)sub(s)-νsub(c)sub(a)sub(l) is found to decrease from 2 to -3 cm -1 as the rotational levels (upsilon' = 27-30), where νsub(c)sub(a)sub(l) is the calculated transition frequency using the Dunham coefficients of Demtroeder and Stock for the X 1 Σ + sub(g) band and of Kusch and Hessel for the A 1 Σ + sub(u) band. (orig.)

Design and implementation of low profile antenna for dual-band applications using rotated e-shaped conductor-backed plane.

Science.gov (United States)

Jalali, Mahdi; Sedghi, Tohid; Shafei, Shahin

2014-01-01

A novel configuration of a printed monopole antenna with a very compact size for satisfying WLAN operations at the 5.2/5.8 GHz and also for X-band operations at the 10 GHz has been proposed. The antenna includes a simple square-shaped patch as the radiator, the rotated U-shaped conductor back plane element with embedded strip on it, and the partial rectangular ground surface. By using the rotated U-shaped conductor-backed plane with proper values, good impedance matching and improvement in bandwidth can be achieved, at the lower and upper bands. The impedance bandwidth for S11 WLAN-band and 4.2 dBi at X-band. The experimental results represent that the realized antenna with good omnidirectional radiation characteristics, enough impedance bandwidth, and reasonable gains can be appropriate for various applications of the future developed technologies and handheld devices.

The rotational spectrum of IBr

International Nuclear Information System (INIS)

Tiemann, E.; Moeller, T.

1975-01-01

The microwave spectrum of IBr was measured in the low rotational transition J = 3 → 2 in order to resolve the hyperfine structure as completely as possible. Rotational constants and quadrupole coupling constants were derived for both nuclei. The observation of the rotational spectrum in different vibrational states yields the vibrational dependence of the rotational constants as well as of the hyperfine parameters. The Dunham potential coefficients α 0 , α 1 , α 2 , α 3 are given. (orig.) [de

A projection-based model reduction strategy for the wave and vibration analysis of rotating periodic structures

Science.gov (United States)

Beli, D.; Mencik, J.-M.; Silva, P. B.; Arruda, J. R. F.

2018-05-01

The wave finite element method has proved to be an efficient and accurate numerical tool to perform the free and forced vibration analysis of linear reciprocal periodic structures, i.e. those conforming to symmetrical wave fields. In this paper, its use is extended to the analysis of rotating periodic structures, which, due to the gyroscopic effect, exhibit asymmetric wave propagation. A projection-based strategy which uses reduced symplectic wave basis is employed, which provides a well-conditioned eigenproblem for computing waves in rotating periodic structures. The proposed formulation is applied to the free and forced response analysis of homogeneous, multi-layered and phononic ring structures. In all test cases, the following features are highlighted: well-conditioned dispersion diagrams, good accuracy, and low computational time. The proposed strategy is particularly convenient in the simulation of rotating structures when parametric analysis for several rotational speeds is usually required, e.g. for calculating Campbell diagrams. This provides an efficient and flexible framework for the analysis of rotordynamic problems.

Highly-distorted and doubly-decoupled rotational bands in odd-odd nuclei

International Nuclear Information System (INIS)

McHarris, W.C.; Olivier, W.A.; Rios, A.; Hampton, C.; Chou, Wentsae; Aryaeinejad, R.

1991-01-01

Heavy-ion reactions induce large amounts of angular momentum; hence, they selectively populate rotationally-aligned particle states in compound nuclei. Such states tend to deexcite through similar states connected by large coriolis matrix elements, resulting in relatively few - but highly distorted - bands in the lower-energy portions of odd-odd spectra. The extreme cases of this are doubly-decoupled, K ∼ 1 (π 1/2 x ν 1/2) bands, whose γ transitions are the most intense in spectra from many light Re and Ir nuclei. The authors made a two-pronged assault on such bands, studying them via different HI reactions at different laboratories and using interacting-boson (IBFFA) calculations to aid in sorting them out. The authors are beginning to understand the types of (primarily coriolis) distortions involved and hope to grasp a handle on aspects of the p-n residual interaction, although the coriolis distortions are large enough to mask much of the latter. They also discuss similar but complementary effects in the light Pr region

Asymptotically-correct description of vibration-rotation spectrum of diatomic molecule with hydrogen iodide molecule as example

International Nuclear Information System (INIS)

Burenin, A.V.; Ryabikin, M.Yu.

1990-01-01

Asymptotically correct series of perturbation theory was constructed analytically to describe the vibration-rotational spectrum of diatomic molecule in Born-Oppenheimer approximation. The series was used for processing of precision experimental data on frequencies of absorption of hydrogen iodide molecule. Advantage of this approach over Dunham approach is shown. Isotope ratios for spectroscopic constants of asymptotically correct series are considered

Determination of band-structure parameters of Pbsub(1-x)Snsub(x)Te narrow-gap semiconductor from infrared Faraday rotation

International Nuclear Information System (INIS)

Sizov, F.F.; Lashkarev, G.V.; Martynchuk, E.K.

1977-01-01

The temeprature dependences of Faraday rotation in Pbsub(1-x)Snsub(x)Te of p type with the hole density 3x10 16 -2.2x10 18 cm -3 are studied in the range 40-370 K and in the spectral interval 4-16 μm. The analysis of interband Faraday rotation confirms a conclusion made by the authors earlier that the g factor for the c band (gsub(c)) is positive, for the v band (gsub(v))-negative and that [gsub(c)] > [gsub(v)]. The temperature dependences of carrier effective masses are investigated on the basis of the two-band model. It is demonstrated that for T < 200 K the Faraday effective mass of holes near the ceiling of the valency band varies in direct proportion to the width of the forbidden band. The temperature increase of the Faraday effective mass of current carriers, which is faster than that of the effective electron mass, is discovered, and this is related to the effect of the heavy hole band

Abnormal vibration of turbine due to oil whip

International Nuclear Information System (INIS)

Koo, Jae Raeyang; Hwang, Jae Hyeon

2001-01-01

Almost all rotating machinery has bearings. Bearing is one of the most important part of rotating machinery. Vibration of rotating machinery depend on its bearing conditions. Bearing conditions are following; oil gap, bearing type, bearing temperature, bearing oil condition. Especially, bearing oil condition influences on rotating machinery vibration directly. In this paper we have discussed the abnormal vibration of turbine due to oil condition. Oil whip problem was occurred in the certain power plant and we had solved this problem through the control of operating values and alignment

Shaft Crack Identification Based on Vibration and AE Signals

Directory of Open Access Journals (Sweden)

Wenxiu Lu

2011-01-01

Full Text Available The shaft crack is one of the main serious malfunctions that often occur in rotating machinery. However, it is difficult to locate the crack and determine the depth of the crack. In this paper, the acoustic emission (AE signal and vibration response are used to diagnose the crack. The wavelet transform is applied to AE signal to decompose into a series of time-domain signals, each of which covers a specific octave frequency band. Then an improved union method based on threshold and cross-correlation method is applied to detect the location of the shaft crack. The finite element method is used to build the model of the cracked rotor, and the crack depth is identified by comparing the vibration response of experiment and simulation. The experimental results show that the AE signal is effective and convenient to locate the shaft crack, and the vibration signal is feasible to determine the depth of shaft crack.

Far-infrared high resolution synchrotron FTIR spectroscopy of the ν11 bending vibrational fundamental transition of dimethylsulfoxyde

Science.gov (United States)

Cuisset, Arnaud; Nanobashvili, Lia; Smirnova, Irina; Bocquet, Robin; Hindle, Francis; Mouret, Gaël; Pirali, Olivier; Roy, Pascale; Sadovskií, Dmitrií A.

2010-05-01

We report the first successful high resolution gas phase study of the 'parallel' band of DMSO at 380 cm -1 associated with the ν11 bending vibrational mode. The spectrum was recorded with a resolution of 0.0015 cm -1 using the AILES beamline of the SOLEIL synchrotron source, the IFS 125 FTIR spectrometer and a multipass cell providing an optical path of 150 m. The rotational constants and centrifugal corrections obtained from the analysis of the resolved rotational transitions reproduce the spectrum to the experimental accuracy.

Collective dipole rotational bands in the A {approx} 200 region

Energy Technology Data Exchange (ETDEWEB)

Clark, R M; Wadsworth, R; Regan, P H [York Univ. (United Kingdom). Dept. of Physics; Paul, E S; Beausang, C W; Ali, I; Cullen, D M; Dagnall, P J; Fallon, P; Joyce, M J; Sharpey-Schafer, J F [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Astier, A; Meyer, M; Redon, N [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Nazakewicz, W; Wyss, R [Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States)

1992-08-01

Rotational oblate bands consisting of regular sequences of magnetic dipole transitions have recently been identified in {sup 196-200}Pb. Their observation indicates a drastic change in the high-spin configurations between the Hg, Tl and {sup 194}Pb nuclei, in which SD bands are clearly observed, and the heavier Pb isotopes, where these weakly deformed oblate structures see to dominate. Angular correlation ratios show the transitions to be dipoles. Their magnetic nature can be deduced from intensity measurements, and they are characterized by small dynamic moments of inertia. Several of the bands have been interpreted as being built on high-K two-proton configurations coupled to an aligned pair of i{sub 13/2} neutrons in the even A nuclei, and to either one or three i{sub 13/2} neutrons in the odd A nuclei. Cranked shell model calculations predict the alignment of a pair of i{sub 13/2} neutrons (the AB crossing) at {omega} {approx} 0.18 MeV{Dirac_h}{sub -1}. The higher frequency crossing at {omega} {approx} 0.4 MeV{Dirac_h}{sub -1} may be due to the alignment of f{sub 5/2} neutrons, h{sub 11/2} protons, or both. 17 refs., 4 figs.

Pairing vibrational and isospin rotational states in a particle number and isospin projected generator coordinate method

International Nuclear Information System (INIS)

Chen, H.T.; Muether, H.; Faessler, A.

1978-01-01

Pairing vibrational and isospin rotational states are described in different approximations based on particle number and isospin projected, proton-proton, neutron-neutron and proton-neutron pairing wave functions and on the generator coordinate method (GCM). The investigations are performed in models for which an exact group theoretical solution exists. It turns out that a particle number and isospin projection is essential to yield a good approximation to the ground state or isospin yrast state energies. For strong pairing correlations (pairing force constant equal to the single-particle level distance) isospin cranking (-ωTsub(x)) yields with particle number projected pairing wave function also good agreement with the exact energies. GCM wave functions generated by particle number and isospin projected BCS functions with different amounts of pairing correlations yield for the lowest T=0 and T=2 states energies which are practically indistinguishable from the exact solutions. But even the second and third lowest energies of charge-symmetric states are still very reliable. Thus it is concluded that also in realistic cases isospin rotational and pairing vibrational states may be described in the framework of the GCM method with isospin and particle number projected generating wave functions. (Auth.)

Algebraic descriptions of nuclear and molecular rotation-vibration spectra

International Nuclear Information System (INIS)

Roosmalen, O.S. van.

1982-01-01

The application of algebraic models to the description of rotational and vibrational degrees of freedom of nuclei and molecules are discussed. Simple model Hamiltonians are shown to give good agreement with the energy spectra of diatomic molecules and nuclei. Some formal aspects of path integral methods for many-boson systems are treated. The two representations for the quantum mechanical propagator are compared and appear to be identical in leading order in 1/N (N is the number of bosons). Approximations for both are static and dynamic problems are discussed. Applications of mean field techniques are also treated. A description of tri- and tetra-atomic molecules in terms of a U(4)xU(4) and U(4)xU(4)xU(4) group structure is given. Linear molecules appear to correspond with symmetries of O(4) type. S-matrix elements are calculated to test mean field methods, and the results compared with exact calculations. (Auth.)

The ALI-ARMS Code for Modeling Atmospheric non-LTE Molecular Band Emissions: Current Status and Applications

Science.gov (United States)

Kutepov, A. A.; Feofilov, A. G.; Manuilova, R. O.; Yankovsky, V. A.; Rezac, L.; Pesnell, W. D.; Goldberg, R. A.

2008-01-01

The Accelerated Lambda Iteration (ALI) technique was developed in stellar astrophysics at the beginning of 1990s for solving the non-LTE radiative transfer problem in atomic lines and multiplets in stellar atmospheres. It was later successfully applied to modeling the non-LTE emissions and radiative cooling/heating in the vibrational-rotational bands of molecules in planetary atmospheres. Similar to the standard lambda iterations ALI operates with the matrices of minimal dimension. However, it provides higher convergence rate and stability due to removing from the iterating process the photons trapped in the optically thick line cores. In the current ALI-ARMS (ALI for Atmospheric Radiation and Molecular Spectra) code version additional acceleration of calculations is provided by utilizing the opacity distribution function (ODF) approach and "decoupling". The former allows replacing the band branches by single lines of special shape, whereas the latter treats non-linearity caused by strong near-resonant vibration-vibrational level coupling without additional linearizing the statistical equilibrium equations. Latest code application for the non-LTE diagnostics of the molecular band emissions of Earth's and Martian atmospheres as well as for the non-LTE IR cooling/heating calculations are discussed.

Gamma spectroscopical studies of strongly deformed rotational bands in 73Br and 79Sr

International Nuclear Information System (INIS)

Heese, J.

1989-01-01

In the framework of this thesis the excitation structures of the nuclei 73 Br and 79 Sr were studied. For the population of high-spin states the reactions 40 Ca( 36 Ar,3p) 73 Br, -58 Ni( 24 Mg,2αp) 73 Br and 58 Ni( 24 Mg,2pn) 79 Sr were used. The level scheme of 73 Br could be extended by γγ coincidence measurements by 18 new states up to the spins 45/2 + respectively 45/2 - . DSA lifetime measurements yielded information about the deformations of the observed rotational bands. The conversion coefficients of the low-energetic transitions in the range of the excitation spectrum below 500 keV were determined and allowed the assignments of spins and parities. Furthermore the converted decay of the 27-keV state was observed for the first time, from the measured intensities of the electron line the lifetime of this state was estimated to 1.1 ≤ τ ≤ 9.1 μs. The measurement of the lifetime and the g factor of the isomeric 240-keV state confirmed the already known spin values and allowed statements on the particle structure. Lifetime measurements in 79 Sr were performed up to the states 21/2 + and 17/2 - . They yielded informations on E2 and M1 transition strengthened in the rotational bands. The transition strengths calculated from the lifetimes show that both nuclei are strongly prolate deformed. The sign of the deformation could be concluded in the case of 73 Br from the observed band structure, in 79 Sr it was calculated from E2/M1 mixing ratios. The E2-transition strengths show a reduction in both nuclei in the region of the g 9/2 proton alignment. Alignment effects in the rotational bands were discussed in the framework of the cranked shell model. Microscopical calculations in the Hartree-Fock-Bogolyubov cranking model with a deformed Woods-Saxon potential were performed. (orig./HSI) [de

A methodology for low-speed broadband rotational energy harvesting using piezoelectric transduction and frequency up-conversion

International Nuclear Information System (INIS)

Fu, Hailing; Yeatman, Eric M.

2017-01-01

Energy harvesting from vibration for low-power electronics has been investigated intensively in recent years, but rotational energy harvesting is less investigated and still has some challenges. In this paper, a methodology for low-speed rotational energy harvesting using piezoelectric transduction and frequency up-conversion is analysed. The system consists of a piezoelectric cantilever beam with a tip magnet and a rotating magnet on a revolving host. The angular kinetic energy of the host is transferred to the vibration energy of the piezoelectric beam via magnetic coupling between the magnets. Frequency up-conversion is achieved by magnetic plucking, converting low frequency rotation into high frequency vibration of the piezoelectric beam. A distributed-parameter theoretical model is presented to analyse the electromechanical behaviour of the rotational energy harvester. Different configurations and design parameters were investigated to improve the output power of the device. Experimental studies were conducted to validate the theoretical estimation. The results illustrate that the proposed method is a feasible solution to collecting low-speed rotational energy from ambient hosts, such as vehicle tires, micro-turbines and wristwatches. - Highlights: • A topology to harvest low-frequency broad-band rotational energy is studied. • Different configurations were considered; arrangement (a)-repulsive was the best. • Theoretical analysis shows the harvester has a wide bandwidth at low frequency. • The ripples of output power are related to the beam's natural frequency. • Experimental results show a good performance (over 20 μW) from 15 Hz to 35 Hz.

Automated misfire diagnosis in engines using torsional vibration and block rotation

International Nuclear Information System (INIS)

Chen, J; Randall, R B; Peeters, B; Auweraer, H Van der; Desmet, W

2012-01-01

Even though a lot of research has gone into diagnosing misfire in IC engines, most approaches use torsional vibration of the crankshaft, and only a few use the rocking motion (roll) of the engine block. Additionally, misfire diagnosis normally requires an expert to interpret the analysis results from measured vibration signals. Artificial Neural Networks (ANNs) are potential tools for the automated misfire diagnosis of IC engines, as they can learn the patterns corresponding to various faults. This paper proposes an ANN-based automated diagnostic system which combines torsional vibration and rotation of the block for more robust misfire diagnosis. A critical issue with ANN applications is the network training, and it is improbable and/or uneconomical to expect to experience a sufficient number of different faults, or generate them in seeded tests, to obtain sufficient experimental results for the network training. Therefore, new simulation models, which can simulate combustion faults in engines, were developed. The simulation models are based on the thermodynamic and mechanical principles of IC engines and therefore the proposed misfire diagnostic system can in principle be adapted for any engine. During the building process of the models, based on a particular engine, some mechanical and physical parameters, for example the inertial properties of the engine parts and parameters of engine mounts, were first measured and calculated. A series of experiments were then carried out to capture the vibration signals for both normal condition and with a range of faults. The simulation models were updated and evaluated by the experimental results. Following the signal processing of the experimental and simulation signals, the best features were selected as the inputs to ANN networks. The automated diagnostic system comprises three stages: misfire detection, misfire localization and severity identification. Multi-layer Perceptron (MLP) and Probabilistic Neural Networks were

A new potential energy surface for vibration-vibration coupling in HF-HF collisions. Formulation and quantal scattering calculations

Science.gov (United States)

Schwenke, David W.; Truhlar, Donald G.

1988-04-01

We present new ab initio calculations of the HF-HF interaction potential for the case where both molecules are simultaneously displaced from their equilibrium internuclear distance. These and previous ab initio calculations are then fit to a new analytic representation which is designed to be efficient to evaluate and to provide an especially faithful account of the forces along the vibrational coordinates. We use the new potential for two sets of quantal scattering calculations for collisions in three dimensions with total angular momentum zero. First we test that the angular harmonic representation of the anisotropy is adequate by comparing quantal rigid rotator calculations to those carried out for potentials involving higher angular harmonics and for which the expansion in angular harmonics is systematically increased to convergence. Then we carry out large-scale quantal calculations of vibration-vibration energy transfer including the coupling of both sets of vibrational and rotational coordinates. These calculations indicate that significant rotational energy transfer accompanies the vibration-to-vibration energy transfer process.

Rotational Laser Cooling of Vibrationally and Translationally Cold Molecular Ions

DEFF Research Database (Denmark)

Drewsen, Michael

2011-01-01

an excellent alternative to atomic qubits in the realization of a practical ion trap based quantum computer due to favourable internal state decoherence rates. In chemistry, state prepared molecular targets are an ideal starting point for uni-molecular reactions, including coherent control...... of photofragmentation through the application of various laser sources [5,6]. In cold bi-molecular reactions, where the effect of even tiny potential barriers becomes significant, experiments with state prepared molecules can yield important information on the details of the potential curves of the molecular complexes...... by sympathetic cooling with Doppler laser cooled Mg+ ions. Giving the time for the molecules to equilibrate internally to the room temperature blackbody radiation, the vibrational degree of freedom will freeze out, leaving only the rotational degree of freedom to be cooled. We report here on the implementation...

Collective motions and band structures in A = 60 to 80, even--even nuclei

International Nuclear Information System (INIS)

Hamilton, J.H.; Robinson, R.L.; Ramayya, A.V.

1978-01-01

Evidence for and the theoretical understanding of the richness of the collective band structures as illustrated by at least seven bands seen in levels of 68 Ge, 74 Se are reviewed. The experimental data on even-even nuclei in the A = 60 to 80 region have now revealed a wide variety of collective bands with different structures. The even parity yrast cascades alone are seen to involve multiple collective structures. In addition to the ground-state bands, strong evidence is presented for both neutron and proton rotation-aligned bands built on the same orbital, (g 9 / 2 ) 2 , in one nucleus. Several other nuclei also show the crossing of RAL bands around the 8 + level in this region. Evidence continues to be strong experimentally and supported theoretically that there is some type of shape transition and shape coexistence occurring now both in the Ge and Se isotopes around N = 40. Negative parity bands with odd and even spins with very collective nature are seen in several nuclei to high spin. These bands seem best understood in the RAL model. Very collective bands with ΔI = 1, extending from 2 + to 9 + are seen with no rotation-alignment. The purity of these bands and their persistence to such high spin establish them as an independent collective mode which is best described as a gamma-type vibration band in a deformed nucleus. In addition to all of the above bands, new bands are seen in 76 Kr and 74 Se. The nature of these bands is not presently known. 56 references

Global Multi-isotopologue fit of measured rotation and vibration-rotation line positions of CO in X1Σ+ state and new set of mass-independent Dunham coefficients

International Nuclear Information System (INIS)

Velichko, T.I.; Mikhailenko, S.N.; Tashkun, S.A.

2012-01-01

A set of mass-independent U mj and Δ mj parameters globally describing vibration-rotation energy levels of the CO molecule in the X 1 Σ + ground electronic state was fitted to more than 19,000 transitions of 12 C 16 O, 13 C 16 O, 14 C 16 O, 12 C 17 O, 13 C 17 O, 12 C 18 O, and 13 C 18 O isotopologues collected from the literature. The maximal values of the vibrational V and the rotational J quantum numbers included in the fit was 41 and 128, respectively. The weighted standard deviation of the fit is .66. Fitted parameters were used for calculation of Dunham coefficients Y mj for nine isotopologues 12 C 16 O, 13 C 16 O, 14 C 16 O, 12 C 17 O, 13 C 17 O, 14 C 17 O, 12 C 18 O, 13 C 18 O, and 14 C 18 O. Calculated transition frequencies based on the fitted parameters were compared with previously reported. A critical analysis of the CO HITRAN and HITEMP data is also presented.

Vibration Stabilization of a Mechanical Model of a X-Band Linear Collider Final Focus Magnet

CERN Document Server

Frisch, J; Decker, V; Hendrickson, L; Markiewicz, T W; Partridge, R; Seryi, Andrei

2004-01-01

The small beam sizes at the interaction point of a X-band linear collider require mechanical stabilization of the final focus magnets at the nanometer level. While passive systems provide adequate performance at many potential sites, active mechanical stabilization is useful if the natural or cultural ground vibration is higher than expected. A mechanical model of a room temperature linear collider final focus magnet has been constructed and actively stabilized with an accelerometer based system.

Vibration Stabilization of a Mechanical Model of a X-Band Linear Collider Final Focus Magnet

International Nuclear Information System (INIS)

Frisch, Josef; Chang, Allison; Decker, Valentin; Doyle, Eric; Eriksson, Leif; Hendrickson, Linda; Himel, Thomas; Markiewicz, Thomas; Partridge, Richard; Seryi, Andrei; SLAC

2006-01-01

The small beam sizes at the interaction point of a X-band linear collider require mechanical stabilization of the final focus magnets at the nanometer level. While passive systems provide adequate performance at many potential sites, active mechanical stabilization is useful if the natural or cultural ground vibration is higher than expected. A mechanical model of a room temperature linear collider final focus magnet has been constructed and actively stabilized with an accelerometer based system

Protonated Nitrous Oxide, NNOH(+): Fundamental Vibrational Frequencies and Spectroscopic Constants from Quartic Force Fields

Science.gov (United States)

Huang, Xinchuan; Fortenberry, Ryan C.; Lee, Timothy J.

2013-01-01

The interstellar presence of protonated nitrous oxide has been suspected for some time. Using established high-accuracy quantum chemical techniques, spectroscopic constants and fundamental vibrational frequencies are provided for the lower energy O-protonated isomer of this cation and its deuterated isotopologue. The vibrationally-averaged B0 and C0 rotational constants are within 6 MHz of their experimental values and the D(subJ) quartic distortion constants agree with experiment to within 3%. The known gas phase O-H stretch of NNOH(+) is 3330.91 cm(exp-1), and the vibrational configuration interaction computed result is 3330.9 cm(exp-1). Other spectroscopic constants are also provided, as are the rest of the fundamental vibrational frequencies for NNOH(+) and its deuterated isotopologue. This high-accuracy data should serve to better inform future observational or experimental studies of the rovibrational bands of protonated nitrous oxide in the ISM and the laboratory.

Rotational structure in molecular infrared spectra

CERN Document Server

di Lauro, Carlo

2013-01-01

Recent advances in infrared molecular spectroscopy have resulted in sophisticated theoretical and laboratory methods that are difficult to grasp without a solid understanding of the basic principles and underlying theory of vibration-rotation absorption spectroscopy. Rotational Structure in Molecular Infrared Spectra fills the gap between these recent, complex topics and the most elementary methods in the field of rotational structure in the infrared spectra of gaseous molecules. There is an increasing need for people with the skills and knowledge to interpret vibration-rotation spectra in many scientific disciplines, including applications in atmospheric and planetary research. Consequently, the basic principles of vibration-rotation absorption spectroscopy are addressed for contemporary applications. In addition to covering operational quantum mechanical methods, spherical tensor algebra, and group theoretical methods applied to molecular symmetry, attention is also given to phase conventions and their effe...

Performance enhancement of a rotational energy harvester utilizing wind-induced vibration of an inclined stay cable

International Nuclear Information System (INIS)

Kim, In-Ho; Jung, Hyung-Jo; Jang, Seon-Jun

2013-01-01

In this paper, an innovative strategy for improving the performance of a recently developed rotational energy harvester is proposed. Its performance can be considerably enhanced by replacing the electromagnetic induction part, consisting of moving permanent magnets and a fixed solenoid coil, with a moving mass and a rotational generator (i.e., an electric motor). The proposed system is easily tuned to the natural frequency of a target structure using the position change of a proof mass. Owing to the high efficiency of the rotational generator, the device can more effectively harness electrical energy from the wind-induced vibration of a stay cable. Also, this new configuration makes the device more compact and geometrically tunable. In order to validate the effectiveness of the new configuration, a series of laboratory and field tests are carried out with the prototype of the proposed device, which is designed and fabricated based on the dynamic characteristics of the vibration of a stay cable installed in an in-service cable-stayed bridge. From the field test, it is observed that the normalized output power of the proposed system is 35.67 mW (m s −2 ) −2 , while that of the original device is just 5.47 mW (m s −2 ) −2 . These results show that the proposed device generates much more electrical energy than the original device. Moreover, it is verified that the proposed device can generate sufficient electricity to power a wireless sensor node placed on a cable under gentle–moderate wind conditions. (paper)

Broadband Vibration Attenuation Using Hybrid Periodic Rods

Directory of Open Access Journals (Sweden)

S. Asiri

2008-12-01

Full Text Available This paper presents both theoretically and experimentally a new kind of a broadband vibration isolator. It is a table-like system formed by four parallel hybrid periodic rods connected between two plates. The rods consist of an assembly of periodic cells, each cell being composed of a short rod and piezoelectric inserts. By actively controlling the piezoelectric elements, it is shown that the periodic rods can efficiently attenuate the propagation of vibration from the upper plate to the lower one within critical frequency bands and consequently minimize the effects of transmission of undesirable vibration and sound radiation. In such a system, longitudinal waves can propagate from the vibration source in the upper plate to the lower one along the rods only within specific frequency bands called the "Pass Bands" and wave propagation is efficiently attenuated within other frequency bands called the "Stop Bands". The spectral width of these bands can be tuned according to the nature of the external excitation. The theory governing the operation of this class of vibration isolator is presented and their tunable filtering characteristics are demonstrated experimentally as functions of their design parameters. This concept can be employed in many applications to control the wave propagation and the force transmission of longitudinal vibrations both in the spectral and spatial domains in an attempt to stop/attenuate the propagation of undesirable disturbances.

Rotational Laser Cooling of Vibrationally and Translationally Cold Molecular Ions

DEFF Research Database (Denmark)

Drewsen, Michael

2011-01-01

[7,8,9]. Furthermore, in order to learn more about the chemistry in interstellar clouds, astrochemists can benefit greatly from direct measurements on cold reactions in laboratories [9]. Working with MgH+ molecular ions in a linear Paul trap, we routinely cool their translational degree of freedom...... by sympathetic cooling with Doppler laser cooled Mg+ ions. Giving the time for the molecules to equilibrate internally to the room temperature blackbody radiation, the vibrational degree of freedom will freeze out, leaving only the rotational degree of freedom to be cooled. We report here on the implementation...... results imply that, through this technique, cold molecular-ion experiments can now be carried out at cryogenic temperatures in room-temperature set-ups. References [1] Koelemeij, J. C. J., Roth, B., Wicht, A., Ernsting, I. and Schiller, S., Phys. Rev. Lett. 98, 173002 (2007). [2] Hudson, J. J., Sauer, B...

Ethane in Planetary and Cometary Atmospheres: Transmittance and Fluorescence Models of the nu7 Band at 3.3 Micrometers

Science.gov (United States)

Villanueva, G. L.; Mumma, M. J.; Magee-Sauer, K.

2011-01-01

Ethane and other hydrocarbon gases have strong rovibrational transitions in the 3.3 micron spectral region owing to C-H, CH2, and CH3 vibrational modes, making this spectral region prime for searching possible biomarker gases in extraterrestrial atmospheres (e.g., Mars, exoplanets) and organic molecules in comets. However, removing ethane spectral signatures from high-resolution terrestrial transmittance spectra has been imperfect because existing quantum mechanical models have been unable to reproduce the observed spectra with sufficient accuracy. To redress this problem, we constructed a line-by-line model for the n7 band of ethane (C2H6) and applied it to compute telluric transmittances and cometary fluorescence efficiencies. Our model considers accurate spectral parameters, vibration-rotation interactions, and a functional characterization of the torsional hot band. We integrated the new band model into an advanced radiative transfer code for synthesizing the terrestrial atmosphere (LBLRTM), achieving excellent agreement with transmittance data recorded against Mars using three different instruments located in the Northern and Southern hemispheres. The retrieved ethane abundances demonstrate the strong hemispheric asymmetry noted in prior surveys of volatile hydrocarbons. We also retrieved sensitive limits for the abundance of ethane on Mars. The most critical validation of the model was obtained by comparing simulations of C2H6 fluorescent emission with spectra of three hydrocarbon-rich comets: C/2004 Q2 (Machholz), 8P/Tuttle, and C/2007 W1 (Boattini). The new model accurately describes the complex emission morphology of the nu7 band at low rotational temperatures and greatly increases the confidence of the retrieved production rates (and rotational temperatures) with respect to previously available fluorescence models.

The Impact of Complex Forcing on the Viscous Torsional Vibration Damper’s Work in the Crankshaft of the Rotating Combustion Engine

Directory of Open Access Journals (Sweden)

Jagiełowicz-Ryznar C.

2016-12-01

Full Text Available The numerical calculations results of torsional vibration of the multi-cylinder crankshaft in the serial combustion engine (MC, including a viscous damper (VD, at complex forcing, were shown. In fact, in the MC case the crankshaft rotation forcings spectrum is the sum of harmonic forcing whose amplitude can be compared with the amplitude of the 1st harmonic. A significant impact, in the engine operational velocity, on the vibration damping process of MC, may be the amplitude of the 2nd harmonic of a forcing moment. The calculations results of MC vibration, depending on the amplitude of the 2nd harmonic of the forcing moment, for the first form of the torsional vibration, were shown. Higher forms of torsional vibrations have no practical significance. The calculations assume the optimum damping coefficient VD, when the simple harmonic forcing is equal to the base critical velocity of the MC crankshaft.

Research on Free Vibration Frequency Characteristics of Rotating Functionally Graded Material Truncated Conical Shells with Eccentric Functionally Graded Material Stringer and Ring Stiffeners

Directory of Open Access Journals (Sweden)

Dao Van Dung

Full Text Available Abstract In this research work, an exact analytical solution for frequency characteristics of the free vibration of rotating functionally graded material (FGM truncated conical shells reinforced by eccentric FGM stringers and rings has been investigated by the displacement function method. Material properties of shell and stiffeners are assumed to be graded in the thickness direction according to a simple power law distribution. The change of spacing between stringers is considered. Using the Donnell shell theory, Leckhnisky smeared stiffeners technique and taking into account the influences of centrifugal force and Coriolis acceleration the governing equations are derived. For stiffened FGM conical shells, it is difficult that free vibration equations are a couple set of three variable coefficient partial differential equations. By suitable transformations and applying Galerkin method, this difficulty is overcome in the paper. The sixth order polynomial equation for w is obtained and it is used to analyze the frequency characteristics of rotating ES-FGM conical shells. Effects of stiffener, geometrics parameters, cone angle, vibration modes and rotating speed on frequency characteristics of the shell forward and backward wave are discussed in detail. The present approach proves to be reliable and accurate by comparing with published results available in the literature.

Machine Fault Detection Based on Filter Bank Similarity Features Using Acoustic and Vibration Analysis

Directory of Open Access Journals (Sweden)

Mauricio Holguín-Londoño

2016-01-01

Full Text Available Vibration and acoustic analysis actively support the nondestructive and noninvasive fault diagnostics of rotating machines at early stages. Nonetheless, the acoustic signal is less used because of its vulnerability to external interferences, hindering an efficient and robust analysis for condition monitoring (CM. This paper presents a novel methodology to characterize different failure signatures from rotating machines using either acoustic or vibration signals. Firstly, the signal is decomposed into several narrow-band spectral components applying different filter bank methods such as empirical mode decomposition, wavelet packet transform, and Fourier-based filtering. Secondly, a feature set is built using a proposed similarity measure termed cumulative spectral density index and used to estimate the mutual statistical dependence between each bandwidth-limited component and the raw signal. Finally, a classification scheme is carried out to distinguish the different types of faults. The methodology is tested in two laboratory experiments, including turbine blade degradation and rolling element bearing faults. The robustness of our approach is validated contaminating the signal with several levels of additive white Gaussian noise, obtaining high-performance outcomes that make the usage of vibration, acoustic, and vibroacoustic measurements in different applications comparable. As a result, the proposed fault detection based on filter bank similarity features is a promising methodology to implement in CM of rotating machinery, even using measurements with low signal-to-noise ratio.

Effect of slow, small movement on the vibration-evoked kinesthetic illusion.

Science.gov (United States)

Cordo, P J; Gurfinkel, V S; Brumagne, S; Flores-Vieira, C

2005-12-01

The study reported in this paper investigated how vibration-evoked illusions of joint rotation are influenced by slow (0.3 degrees /s), small (2-4 degrees ) passive rotation of the joint. Normal human adults (n=15) matched the perceived position of the left ("reference") arm with the right ("matching") arm while vibration (50 pps, 0.5 mm) was applied for 30 s to the relaxed triceps brachii of the reference arm. Both arms were constrained to rotate horizontally at the elbow. Three experimental conditions were investigated: (1) vibration of the stationary reference arm, (2) slow, small passive extension or flexion of the reference arm during vibration, and (3) slow, small passive extension or flexion of the reference arm without vibration. Triceps brachii vibration at 50 pps induced an illusion of elbow flexion. The movement illusion began after several seconds, relatively fast to begin with and gradually slowing down to a stop. On average, triceps vibration produced illusory motion at an average latency of 6.3 s, amplitude of 9.7 degrees , velocity of 0.6 degrees /s, and duration of 16.4 s. During vibration, slow, small ( approximately 0.3 degrees /s, 1.3 degrees ) passive rotations of the joint dramatically enhanced, stopped, or reversed the direction of illusory movement, depending on the direction of the passive joint rotation. However, the subjects' perceptions of these passive elbow rotations were exaggerated: 2-3 times the size of the actual movement. In the absence of vibration, the subjects accurately reproduced these passive joint rotations. We discuss whether the exaggerated perception of slow, small movement during vibration is better explained by contributions of non muscle spindle Ia afferents or by changes in the mechanical transmission of vibration to the receptor.

In-beam γ-spectroscopic study of rotational bands in 103Rh

International Nuclear Information System (INIS)

Kuti, I.; Timar, J.; Sohler, D.; Koike, T.; Lee, I.Y.; Machiavelli, A.O.

2012-01-01

Complete text of publication follows. Earlier studies revealed the existence of chiral partner candidate bands in 103 Rh. In order to construct a more complex level scheme, and to collect more information on the band structure, we studied the experimental properties of the rotational bands of this nucleus. For this analysis, excited states of 103 Rh were populated through the 96 Zr( 11 B,4n) reaction at a beam energy of 40 MeV. The beam, provided by the 88-in. cyclotron of the Lawrence Berkeley National Laboratory (LBNL), impinged on a 500 μg/cm 2 self-supporting target foil. For detection of the emitted γ-rays, the GAMMASPHERE spectrometer was used. Out of a sum of 9x10 9 events, about the 65% could be assigned to 103 Rh. In the present phase of the study, the level scheme was constructed based on γγγ-coincidence relationships, as well as energy and intensity balances of the observed γ-rays. The analysis included the evaluation of 2- and 3-dimensional histograms, using the RADWARE software package. Three typical γγγ-coincidence spectra are shown in Figure 1. We doubled the number of transitions assigned to 103 Rh and we established five new bands to the formerly known six ones. In order to assign firm spin-parities to the states, we plan to make an angular correlation (DCO) analysis for the observed transitions.

The Impact of Complex Forcing on the Viscous Torsional Vibration Damper’s Work in the Crankshaft of the Rotating Combustion Engine

OpenAIRE

Jagiełowicz-Ryznar C.

2016-01-01

The numerical calculations results of torsional vibration of the multi-cylinder crankshaft in the serial combustion engine (MC), including a viscous damper (VD), at complex forcing, were shown. In fact, in the MC case the crankshaft rotation forcings spectrum is the sum of harmonic forcing whose amplitude can be compared with the amplitude of the 1st harmonic. A significant impact, in the engine operational velocity, on the vibration damping process of MC, may be the amplitude of the 2nd harm...

First high resolution analysis of the 3ν2 and 3ν2 -ν2 bands of 32S16O2

Science.gov (United States)

Ulenikov, O. N.; Bekhtereva, E. S.; Gromova, O. V.; Berezkin, K. B.; Horneman, V.-M.; Sydow, C.; Maul, C.; Bauerecker, S.

2017-11-01

The second bending overtone band 3ν2 of sulfur dioxide has been studied for the first time with high resolution rotation-vibration spectroscopy. The 1530 transitions involving 728 upper state energy levels with Jmax.= 53 and Kamax . = 15 have been assigned to the 3ν2 band. The 746 transitions belonging to the 3ν2 -ν2 "hot" band have been also assigned in the region of 950-1100 cm-1. For the analysis of the assigned transitions, an effective Hamiltonian of an isolated (030) vibrational state (the Watson operator in A-reduction and Ir representation) was used. Set of 9 varied parameters was determined which reproduce the initial experimental data with the drms deviations of 9.0 ×10-4 cm-1 and 9.8 ×10-4 cm-1 for the 3ν2 and 3ν2 -ν2 bands, which are comparable with the experimental uncertainties.

PGOPHER: A program for simulating rotational, vibrational and electronic spectra

Science.gov (United States)

Western, Colin M.

2017-01-01

The PGOPHER program is a general purpose program for simulating and fitting molecular spectra, particularly the rotational structure. The current version can handle linear molecules, symmetric tops and asymmetric tops and many possible transitions, both allowed and forbidden, including multiphoton and Raman spectra in addition to the common electric dipole absorptions. Many different interactions can be included in the calculation, including those arising from electron and nuclear spin, and external electric and magnetic fields. Multiple states and interactions between them can also be accounted for, limited only by available memory. Fitting of experimental data can be to line positions (in many common formats), intensities or band contours and the parameters determined can be level populations as well as rotational constants. PGOPHER is provided with a powerful and flexible graphical user interface to simplify many of the tasks required in simulating, understanding and fitting molecular spectra, including Fortrat diagrams and energy level plots in addition to overlaying experimental and simulated spectra. The program is open source, and can be compiled with open source tools. This paper provides a formal description of the operation of version 9.1.

Parameterization of rotational spectra

International Nuclear Information System (INIS)

Zhou Chunmei; Liu Tong

1992-01-01

The rotational spectra of the strongly deformed nuclei with low rotational frequencies and weak band mixture are analyzed. The strongly deformed nuclei are commonly encountered in the rare-earth region (e. g., 150 220). A lot of rotational band knowledge are presented

Rotational bands in the nuclear sup(168)Er and some remarks on their interpretation

International Nuclear Information System (INIS)

Davidson, W.F.; Dixon, W.R.; Storey, R.S.

1984-01-01

Further analysis of previously published data on sup(168)Er, together with results of new measurements of selected portions of the neutron capture γ-ray spectrum, has resulted in the construction of an improved level spectrum for this nucleus. Altogether 127 excited levels have now been established and grouped into 36 rotational bands. Some remarks on their interpretation are advanced

Influence of vibrations and rotations of diatomic molecules on their physical properties: II. Refractive index, reactivity and diffusion coefficients

International Nuclear Information System (INIS)

Sharipov, Alexander S; Loukhovitski, Boris I; Starik, Alexander M

2016-01-01

The influence of the excitation of vibrational and rotational states of diatomic molecules (H 2 , N 2 , O 2 , NO, OH, CO, CH, HF and HCl) on refractive index, reactivity and transport coefficients was analyzed by using ab initio calculated data on the effective state-specific dipole moment and static polarizability obtained in the preceding paper of the present series. It has been revealed that, for non-polar molecules, the excitation both of vibrational and rotational degrees of freedom increases the averaged polarizability and, as a consequence, the refractive index. Meanwhile, for polar molecules, the effect of molecule excitation is more complex: it can either increase or decrease the refractive index. It was also shown that the excitation of molecules slightly influences the rate constants of barrierless chemical reactions between neutral particles; whereas, for ion–molecule reactions, this effect can be more pronounced. Analysis of the variation of diffusion coefficients, taking into account the effect of molecule excitation both on the collision diameter and on the well depth of intermolecular potential, exhibited that, for non-polar molecules, the effect associated with the change of collision diameter prevails. However, for polar molecules, the effect of the excitation of vibrational states on the well depth of intermolecular potential can compensate or even exceed the decrease of diffusion coefficient due to the averaged collision diameter rise. (paper)

Vibrations of beams with a variable cross-section fixed on rotational rigid disks

Directory of Open Access Journals (Sweden)

Slawomir Zolkiewski

Full Text Available The work is focused on the problem of vibrating beams with a variable cross-section fixed on a rotational rigid disk. The beam is loaded by a transversal time varying force orthogonal to an axis of the beam and simultaneously parallel to the disk's plane. There are many ways of usage of the technical moveable systems composed of elements with the variable cross-sections. The main applications are used in numerous types of turbines and pumps. The paper is a kind of introduction to the dynamic analysis of above mentioned beam systems. The equations of motion of rotational beams fixed on the rigid disks were derived. After introducing the Coriolis forces and the centrifugal forces, the transportation effect in the mathematical model was considered. This particular project is the first stage research, where there were proposed certain solutions of problems connected with the linear variable cross-sections systems. The further investigation considering the nonlinear systems has been proceeding. The results, analysis and comparison will be presented in the future works.

Impact of triaxiality on the rotational structure of neutron-rich rhenium isotopes

Directory of Open Access Journals (Sweden)

M.W. Reed

2016-01-01

Full Text Available A number of 3-quasiparticle isomers have been found and characterised in the odd-mass, neutron-rich, 187Re, 189Re and 191Re nuclei, the latter being four neutrons beyond stability. The decay of the isomers populates states in the rotational bands built upon the 9/2−[514] Nilsson orbital. These bands exhibit a degree of signature splitting that increases with neutron number. This splitting taken together with measurements of the M1/E2 mixing ratios and with the changes observed in the energy of the gamma-vibrational band coupled to the 9/2−[514] state, suggests an increase in triaxiality, with γ values of 5°, 18° and 25° deduced in the framework of a particle-rotor model.

NRC sponsored rotating equipment vibration research: a program description and progress report

International Nuclear Information System (INIS)

Nitzel, M.E.

1986-01-01

The Idaho National Engineering Laboratory (INEL) is currently involved in a research project sponsored by the United States Nuclear Regulatory Commission (NRC) regarding operational vibration in rotating equipment. The object of this program is to assess the nature of vibrational failures and the effect that improved qualification standards may have in reducing the incidence of failure. In order to limit the scope of the initial effort, safety injection (SI) pumps were chosen as the component group for concentrated study. The task has been oriented to addressing the issues of whether certain SI pumps experience more failures than others, examining the dynamic environments in operation, examining the adequacy of current qualification standards, and examining what performance parameters could be used more efficiently to predict degradation or failure. Results of a literature search performed to survey SI pump failures indicate that failures are due to a diversity of causes, many of which may not be influenced by qualification criteria. Cooperative efforts have been undertaken with a limited number of nuclear utilities to describe the variety of possible operating environments and to analyze available data. The results of this analysis as they apply to the research issues are presented and possibilities for the future direction of the program are discussed

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.

a Study of Radial Vibrations of a Rolling Tyre for TYRE-ROAD Noise Characterisation

Science.gov (United States)

Périsse, J.

2002-11-01

Because tyre-road noise represents the main noise source for light vehicles with driving speed above 60 km/h, comprehension of generation mechanism of tyre-road noise has become a subject of major importance. In this paper, tyre-road interaction and radial tyre vibrations are investigated for tyre-road noise characterisation. Experimental measurements are performed on a rolling smooth tyre with test laboratory facilities. Both tread band and sidewall responses of the tyre are measured and compared to each other. High concentration of vibrations is observed in the vicinity of the contact area. Stationary radial deformation and non-stationary vibrations due to road rugosity are studied. Frequency analyses have been performed on the acceleration time signals showing the influence of the rotating speed on the vibrations level and frequency content. Finally, by integrating acceleration signal of the tyre tread over one revolution, stationary radial displacement can be calculated and the true contact length can be estimated. This study provides us with new measurement data for comparison with mathematical modelling. It also gives a physical insight on generation mechanism of tyre radial vibrations.

Gerotor and bearing system for whirling mass orbital vibrator

Energy Technology Data Exchange (ETDEWEB)

Brett, James Ford; Westermark, Robert Victor; Turner, Jr., Joey Earl; Lovin, Samuel Scott; Cole, Jack Howard; Myers, Will

2007-02-27

A gerotor and bearing apparatus for a whirling mass orbital vibrator which generates vibration in a borehole. The apparatus includes a gerotor with an inner gear rotated by a shaft having one less lobe than an outer gear. A whirling mass is attached to the shaft. At least one bearing is attached to the shaft so that the bearing engages at least one sleeve. A mechanism is provided to rotate the inner gear, the mass and the bearing in a selected rotational direction in order to cause the mass, the inner gear, and the bearing to backwards whirl in an opposite rotational direction. The backwards whirling mass creates seismic vibrations.

Properties of rotational bands at the spin limit in A {approximately} 50, A {approximately} 65 and A {approximately} 110 nuclei

Energy Technology Data Exchange (ETDEWEB)

Janzen, V.P.; Andrews, H.R.; Ball, G.C. [Chalk River Labs., Ontario (Canada)] [and others

1996-12-31

There is now widespread evidence for the smooth termination of rotational bands in A {approx_equal} 110 nuclei at spins of 40-to-50{Dirac_h}s. The characteristics of these bands are compared to those of bands recently observed to high spin in {sup 64}Zn and {sup 48}Cr, studied with the 8{pi} {gamma}-ray spectrometer coupled to the Chalk River miniball charged-particle-detector array.

MARVEL analysis of the rotational-vibrational states of the molecular ions H2D+ and D2H+.

Science.gov (United States)

Furtenbacher, Tibor; Szidarovszky, Tamás; Fábri, Csaba; Császár, Attila G

2013-07-07

Critically evaluated rotational-vibrational line positions and energy levels, with associated critically reviewed labels and uncertainties, are reported for two deuterated isotopologues of the H3(+) molecular ion: H2D(+) and D2H(+). The procedure MARVEL, standing for Measured Active Rotational-Vibrational Energy Levels, is used to determine the validated levels and lines and their self-consistent uncertainties based on the experimentally available information. The spectral ranges covered for the isotopologues H2D(+) and D2H(+) are 5.2-7105.5 and 23.0-6581.1 cm(-1), respectively. The MARVEL energy levels of the ortho and para forms of the ions are checked against ones determined from accurate variational nuclear motion computations employing the best available adiabatic ab initio potential energy surfaces of these isotopologues. The number of critically evaluated, validated and recommended experimental (levels, lines) are (109, 185) and (104, 136) for H2D(+) and D2H(+), respectively. The lists of assigned MARVEL lines and levels and variational levels obtained for H2D(+) and D2H(+) as part of this study are deposited in the ESI to this paper.

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.)

Nuclear structure and nuclear reaction aspects of Faessler and Greiner's rotation-vibration coupling theory

International Nuclear Information System (INIS)

Aspelund, O.

In the nuclear structure part, the foundations of Faessler and Greiner's rotation-vibration coupling theory are reviewed, whereafter an alternative derivation of Faessler and Greiner's Hamiltonian is presented. A non-spherical quadrupole phonon number N is defined and used in the matrix elements reported for odd-even/even-odd nuclei. These matrix elements are shown to evince oblate-prolate effects that can be exploited for assessing the signs of quadrupole deformations. In the nuclear reaction part, the wave functions emerging from the structure part are applied in a complete and consistent description of elastic and inelastic particle scattering, one-nucleon transfer, and particle/γ-ray angular correlations. The intentions are to demonstrate that anomolous angular distributions and 1=2 j-effects observed in one-nucleon transfer are interrelated phenomena, that can be satisfactorily explained in terms of the elementary vibrational excitation modes inherent in Faessler and Greiner's theory. The latter is regarded as a non-spherical approach to the theory of the quadrupole component of the nuclear potential energy surface. (Auth.)

A 3D finite element model for the vibration analysis of asymmetric rotating machines

Energy Technology Data Exchange (ETDEWEB)

Prabel, B.; Combescure, D. [CEA Saclay, DEN, DM2S, SEMT, DYN, F-91191 Gif Sur Yvette (France); Lazarus, A. [Ecole Polytech, Mecan Solides Lab, F-91128 Palaiseau (France)

2010-07-01

This paper suggests a 3D finite element method based on the modal theory in order to analyse linear periodically time-varying systems. Presentation of the method is given through the particular case of asymmetric rotating machines. First, Hill governing equations of asymmetric rotating oscillators with two degrees of freedom are investigated. These differential equations with periodic coefficients are solved with classic Floquet theory leading to parametric quasi-modes. These mathematical entities are found to have the same fundamental properties as classic Eigenmodes, but contain several harmonics possibly responsible for parametric instabilities. Extension to the vibration analysis (stability, frequency spectrum) of asymmetric rotating machines with multiple degrees of freedom is achieved with a fully 3D finite element model including stator and rotor coupling. Due to Hill expansion, the usual degrees of freedom are duplicated and associated with the relevant harmonic of the Floquet solutions in the frequency domain. Parametric quasi-modes as well as steady-state response of the whole system are ingeniously computed with a component-mode synthesis method. Finally, experimental investigations are performed on a test rig composed of an asymmetric rotor running on non-isotropic supports. Numerical and experimental results are compared to highlight the potential of the numerical method. (authors)

An improved model of radiative transfer for the NLTE problem in the NIR bands of CO2 and CO molecules in the daytime atmosphere of Mars. 2. Population of vibrational states

Science.gov (United States)

Ogibalov, V. P.; Shved, G. M.

2017-09-01

The near-infrared (NIR) emission of the Martian atmosphere in the CO2 bands at 4.3, 2.7, 2.0, 1.6, 1.4, 1.3, 1.2, and 1.05 µm and in the CO bands at 4.7, 2.3, 1.6, and 1.2 µm is mainly generated under nonlocal thermodynamic equilibrium (NLTE) conditions for vibrational states, the transitions from which form the specified bands. The paper presents the results of simulations of the population of these states under NLTE for daytime conditions. In the cold high-latitude troposphere, the NLTE takes place much lower than in the troposphere under typical temperature conditions. If the NIR-radiation reflection from the surface is ignored, the population of high vibrational states substantially decreases, at least, in some layer of the lower atmosphere. However, inelastic collisions of CO2 and CO molecules with O atoms produce no considerable influence on the values of populations. The population of vibrational states, the transitions from which form NIR bands, is also almost insensitive to possible large values of the quenching-in-collision rate constants of vibrational states higher than CO2(0001). However, very large errors in the estimates of the population of vibrational states of the CO2 molecule (rather than the CO molecule!) can be caused by the uncertainty in the values of the rate constant of exchange between CO2 molecules by the energy quantum of the asymmetric stretching vibrational mode. For this intermolecular exchange, we recommend a possible way to restrict the vibrational excitation degree of the molecule that is a collision partner and to maintain simultaneously a sufficiently high accuracy in the population estimate.

Developed vibration waveform monitoring unit for CBM

International Nuclear Information System (INIS)

Hamada, T.; Hotsuta, K.; Hirose, I.; Morita, E.

2007-01-01

In nuclear power plants, many rotating machines such as pumps and fans are in use. Shikoku Research Institute Inc. has recently developed easy-to-use tools to facilitate the maintenance of such equipment. They include a battery-operated vibration waveform monitoring unit which allows unmanned vibration monitoring on a regular basis and data collection even from intermittently operating equipment, a waveform data collector which can be used for easy collection, storage, control, and analysis of raw vibration waveform data during normal operation, and vibration analysis and evaluation tools. A combination of these tools has a high potential for optimization of rotating equipment maintenance. (author)

OH vibrational activation and decay dynamics of CH4-OH entrance channel complexes

International Nuclear Information System (INIS)

Wheeler, Martyn D.; Tsiouris, Maria; Lester, Marsha I.; Lendvay, Gyoergy

2000-01-01

Infrared spectroscopy has been utilized to examine the structure and vibrational decay dynamics of CH 4 -OH complexes that have been stabilized in the entrance channel to the CH 4 +OH hydrogen abstraction reaction. Rotationally resolved infrared spectra of the CH 4 -OH complexes have been obtained in the OH fundamental and overtone regions using an IR-UV (infrared-ultraviolet) double-resonance technique. Pure OH stretching bands have been identified at 3563.45(5) and 6961.98(4) cm-1 (origins), along with combination bands involving the simultaneous excitation of OH stretching and intermolecular bending motions. The infrared spectra exhibit extensive homogeneous broadening arising from the rapid decay of vibrationally activated CH 4 -OH complexes due to vibrational relaxation and/or reaction. Lifetimes of 38(5) and 25(3) ps for CH 4 -OH prepared with one and two quanta of OH excitation, respectively, have been extracted from the infrared spectra. The nascent distribution of the OH products from vibrational predissociation has been evaluated by ultraviolet probe laser-induced fluorescence measurements. The dominant inelastic decay channel involves the transfer of one quantum of OH stretch to the pentad of CH 4 vibrational states with energies near 3000 cm-1. The experimental findings are compared with full collision studies of vibrationally excited OH with CH 4 . In addition, ab initio electronic structure calculations have been carried out to elucidate the minimum energy configuration of the CH 4 -OH complex. The calculations predict a C 3v geometry with the hydrogen of OH pointing toward one of four equivalent faces of the CH 4 tetrahedron, consistent with the analysis of the experimental infrared spectra. (c) 2000 American Institute of Physics

Nonlinear quantum dynamics in diatomic molecules: Vibration, rotation and spin

International Nuclear Information System (INIS)

Yang, Ciann-Dong; Weng, Hung-Jen

2012-01-01

Highlights: ► This paper reveals the internal nonlinear dynamics embedded in a molecular quantum state. ► Analyze quantum molecular dynamics in a deterministic way, while preserving the consistency with probability interpretation. ► Molecular vibration–rotation interaction and spin–orbital coupling are considered simultaneously. ► Spin is just the remnant angular motion when orbital angular momentum is zero. ► Spin is the “zero dynamics” of nonlinear quantum dynamics. - Abstract: For a given molecular wavefunction Ψ, the probability density function Ψ ∗ Ψ is not the only information that can be extracted from Ψ. We point out in this paper that nonlinear quantum dynamics of a diatomic molecule, completely consistent with the probability prediction of quantum mechanics, does exist and can be derived from the quantum Hamilton equations of motion determined by Ψ. It can be said that the probability density function Ψ ∗ Ψ is an external representation of the quantum state Ψ, while the related Hamilton dynamics is an internal representation of Ψ, which reveals the internal mechanism underlying the externally observed random events. The proposed internal representation of Ψ establishes a bridge between nonlinear dynamics and quantum mechanics, which allows the methods and tools already developed by the former to be applied to the latter. Based on the quantum Hamilton equations of motion derived from Ψ, vibration, rotation and spin motions of a diatomic molecule and the interactions between them can be analyzed simultaneously. The resulting dynamic analysis of molecular motion is compared with the conventional probability analysis and the consistency between them is demonstrated.

Description of low-lying states in odd-odd deformed nuclei taking account of the coupling with core rotations and vibrations. 1

International Nuclear Information System (INIS)

Kvasil, J.; Hrivnacova, I.; Nesterenko, V.O.

1990-01-01

The microscopic approach for description of low-lyinig states in deformed odd-odd nuclei is formulated as a generalization of the quasiparticle-phonon model (QPM) with including the rotational degrees of freedom and n-p interaction between external nucleons into the QPM. In comparison with other models, the approach proposed includes all three the most important effects coupling with rotational and vibrational degrees of freedom of doubly-even core and p-n interaction mentioned above even treates them on the microscopic base. 36 refs

Petroleum Pumps’ Current and Vibration Signatures Analysis Using Wavelet Coherence Technique

Directory of Open Access Journals (Sweden)

Rmdan Shnibha

2013-01-01

Full Text Available Vibration analysis is widely used for rotating machinery diagnostics; however measuring vibration of operational oil well pumps is not possible. The pump’s driver’s current signatures may provide condition-related information without the need for an access to the pump itself. This paper investigates the degree of relationship between the pump’s driver’s current signatures and its induced vibration. This relationship between the driver’s current signatures (DCS and its vibration signatures (DVS is studied by calculating magnitude-squared coherence and phase coherence parameters at a certain frequency band using continuous wavelet transform (CWT. The CWT coherence-based technique allows better analysis of temporal evolution of the frequency content of dynamic signals and areas in the time-frequency plane where the two signals exhibit common power or consistent phase behaviour indicating a relationship between the signals. This novel approach is validated by experimental data acquired from 3 kW petroleum pump’s driver. Both vibration and current signatures were acquired under different speed and load conditions. The outcomes of this research suggest the use of DCS analysis as reliable and inexpensive condition monitoring tool, which could be implemented for oil pumps, real-time monitoring associated with condition-based maintenance (CBM program.

Long-lived K isomer and enhanced γ vibration in the neutron-rich nucleus 172Dy: Collectivity beyond double midshell

Directory of Open Access Journals (Sweden)

H. Watanabe

2016-09-01

Full Text Available The level structure of 172Dy has been investigated for the first time by means of decay spectroscopy following in-flight fission of a 238U beam. A long-lived isomeric state with T1/2=0.71(5 s and Kπ=8− has been identified at 1278 keV, which decays to the ground-state and γ-vibrational bands through hindered electromagnetic transitions, as well as to the daughter nucleus 172Ho via allowed β decays. The robust nature of the Kπ=8− isomer and the ground-state rotational band reveals an axially-symmetric structure for this nucleus. Meanwhile, the γ-vibrational levels have been identified at unusually low excitation energy compared to the neighboring well-deformed nuclei, indicating the significance of the microscopic effect on the non-axial collectivity in this doubly mid-shell region. The underlying mechanism of enhanced γ vibration is discussed in comparison with the deformed Quasiparticle Random-Phase Approximation based on a Skyrme energy-density functional.

Collective oblate dipole rotational bands in 198Pb

International Nuclear Information System (INIS)

Clark, R.M.; Wadsworth, R.; Paul, E.S.; Beausang, C.W.; Ali, I.; Astier, A.; Cullen, D.M.; Dagnall, P.J.; Fallon, P.; Joyce, M.J.; Meyer, M.; Redon, N.; Regan, P.H.; Sharpey-Schafer, J.F.; Nazarewicz, W.; Wyss, R.

1993-01-01

The nucleus 198 Pb was populated via the 186 W( 17 O, 5n) 198 Pb reaction at beam energies of 92 and 98 MeV. Five collective rotational cascades of ΔI=1 transitions have been found. Four are highly regular, one much more irregular. The structures are incorporated into a level scheme which extends up to approximately spin 32 h and an excitation energy of about 10 MeV. Angular correlation measurements confirm the dipole character of the interband transitions. Their M1 multipolarity is inferred, and from this supposition the experimental data are interpreted in terms of oblate high-K two quasiproton configurations coupled to aligned neutron excitations. This interpretation is extended to include other ΔI=1 oblate structures observed in 194-201 Pb. It is shown that the pattern of observed moments of inertia can be understood in the simple unpaired picture involving neutron i 13/2 excitations. The identical bands observed are interpreted in terms of the normal-parity weakly-coupled singlet orbital. (orig.)

Three- and five-quasiparticle isomers, rotational bands and residual interactions in 175Hf

International Nuclear Information System (INIS)

Dracoulis, G.D.; Walker, P.M.

1980-03-01

Two 3-quasiparticle isomers with spins, parities and half lives of 19/2 + , 1.1 μ and 23/2 - , 1.2 ns have been identified at 1433 and 1766 keV in 175 Hf. A third isomer possibly 35/2 - with a 1.2 μs half-life is found at 3015 keV. The first two are characterised as a 7/2 + (633) neutron coupled to the known 6 + and 8 - 2-proton isomers of the core nuclei. Rotational bands based on the 3-qp isomers are highly perturbed, due to Coriolis mixing, and their structure is reproduced in a band mixing calculation. The energy depression of the 3-quasiparticle states relative to the 2-quasiproton core states is attributed mainly to the residual proton-neutron interaction, and possibly also to blocking effects through neutron admixtures

A multi-reference filtered-x-Newton narrowband algorithm for active isolation of vibration and experimental investigations

Science.gov (United States)

Wang, Chun-yu; He, Lin; Li, Yan; Shuai, Chang-geng

2018-01-01

In engineering applications, ship machinery vibration may be induced by multiple rotational machines sharing a common vibration isolation platform and operating at the same time, and multiple sinusoidal components may be excited. These components may be located at frequencies with large differences or at very close frequencies. A multi-reference filtered-x Newton narrowband (MRFx-Newton) algorithm is proposed to control these multiple sinusoidal components in an MIMO (multiple input and multiple output) system, especially for those located at very close frequencies. The proposed MRFx-Newton algorithm can decouple and suppress multiple sinusoidal components located in the same narrow frequency band even though such components cannot be separated from each other by a narrowband-pass filter. Like the Fx-Newton algorithm, good real-time performance is also achieved by the faster convergence speed brought by the 2nd-order inverse secondary-path filter in the time domain. Experiments are also conducted to verify the feasibility and test the performance of the proposed algorithm installed in an active-passive vibration isolation system in suppressing the vibration excited by an artificial source and air compressor/s. The results show that the proposed algorithm not only has comparable convergence rate as the Fx-Newton algorithm but also has better real-time performance and robustness than the Fx-Newton algorithm in active control of the vibration induced by multiple sound sources/rotational machines working on a shared platform.

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

The Raman and vibronic activity of intermolecular vibrations in aromatic-containing complexes and clusters

International Nuclear Information System (INIS)

Maxton, P.M.; Schaeffer, M.W.; Ohline, S.M.; Kim, W.; Venturo, V.A.; Felker, P.M.

1994-01-01

Theoretical and experimental results pertaining to the excitation of intermolecular vibrations in the Raman and vibronic spectra of aromatic-containing, weakly bound complexes and clusters are reported. The theoretical analysis of intermolecular Raman activity is based on the assumption that the polarizability tensor of a weakly bound species is given by the sum of the polarizability tensors of its constituent monomers. The analysis shows that the van der Waals bending fundamentals in aromatic--rare gas complexes may be expected to be strongly Raman active. More generally, it predicts strong Raman activity for intermolecular vibrations that involve the libration or internal rotation of monomer moieties having appreciable permanent polarizability anisotropies. The vibronic activity of intermolecular vibrations in aromatic-rare gas complexes is analyzed under the assumption that every vibronic band gains its strength from an aromatic-localized transition. It is found that intermolecular vibrational excitations can accompany aromatic-localized vibronic excitations by the usual Franck--Condon mechanism or by a mechanism dependent on the librational amplitude of the aromatic moiety during the course of the pertinent intermolecular vibration. The latter mechanism can impart appreciable intensity to bands that are forbidden by rigid-molecule symmetry selection rules. The applicability of such rules is therefore called into question. Finally, experimental spectra of intermolecular transitions, obtained by mass-selective, ionization-detected stimulated Raman spectroscopies, are reported for benzene--X (X=Ar, --Ar 2 , N 2 , HCl, CO 2 , and --fluorene), fluorobenzene--Ar and --Kr, aniline--Ar, and fluorene--Ar and --Ar 2 . The results support the conclusions of the theoretical analyses and provide further evidence for the value of Raman methods in characterizing intermolecular vibrational level structures

Ergonomic Evaluation of Vibrations of a Rototiller with New Blade

Directory of Open Access Journals (Sweden)

H Gholami

2017-10-01

Full Text Available Introduction One of the most important problems arising with operation of the conventional rototillers is severe vibration of the machine handle which is transmitted to the user’s hands, arms and shoulders. Long period exposure of the hand-transmitted vibration may cause various diseases such as white finger syndrome. Therefore in this study, vibrations of a new type of rototiller with ridged blades were investigated at the position of handle/hand interface in different working conditions. Finally, the maximum allowable exposure time to the rototiller users in continuous tillage operation was obtained according to ISO 5349-1. Materials and Methods Experiments were carried out in one of the farms with silty clay soil texture, located in Sari city, Mazandaran province, Iran. Vibration measurements were performed according to ISO 5349-1 and ISO 5349-2 standards in two different modes, including in situ mode and tillage mode. Vibrational parameters were obtained in three blade rotational speeds, i.e., low speed (140-170 rpm, medium speed (170-200, and high speed (200-230. Blade rotational speed varied by changing engine speed using the throttle control lever. In each experiment, different vibrational values were individually recorded in three directions (x, y, and z. Experimental design and data analysis were performed in a Randomized Complete Block Design with three replications using the SPSS16 software. Results and Discussion Based on the obtained results in this study, the RMS of acceleration increased by increasing in rotational speed for all of the conducted experiments. The reason is that number of cutting per unit of time and consequently the frequency of changing in the dynamic forces exerting on the blades dramatically increases with increasing the rotational speed of the blades. Noteworthy is that in most cases the variation of acceleration in the tillage mode showed similar trend with vibrational values in the idling mode. This

Rotational dependence of Fermi-type resonance interactions in molecules

Science.gov (United States)

Mikhailov, Vladimir M.; Smirnov, M. A.

1997-03-01

In Pasadena, (Milliken Lab., USA, 1930) F. Rossetti has observed in Raman spectrum of carbon-dioxide molecule the full symmetric vibration of carbon dioxide appeared as the group of four near lying lines instead of the waited single line. The true interpretation of this enigmatic effect (in that time) was given by E. Fermi -- accidental degeneration of the first excited state of the full symmetric vibration in carbon dioxide. It was the first example of the event observed later in various organic molecules. This event was named as resonance Fermi. The rotational dependence of Fermi type resonance interactions in quasirigid molecules in dominant approximation can be selected in an expansion of the effective vibration-rotation Hamiltonian Hvib- roteff by the operator H(g)(Fermi) equals H30 plus (Sigma) nH3n(g). Let us consider in detail the problem of the construction of the effective vibration-rotational Hamiltonian HVR yields Heff from the point of view of various ordering schemes (grouping) of the vibrational-rotational interactions with sequential analysis of the choice of the convenient grouping adequate to the spectroscopic problem.

Spectra and relaxation dynamics of the pseudohalide (PS) vibrational bands for Ru(bpy)2(PS)2 complexes, PS = CN, NCS and N3

International Nuclear Information System (INIS)

Compton, Ryan; Gerardi, Helen K.; Weidinger, Daniel; Brown, Douglas J.; Dressick, Walter J.; Heilweil, Edwin J.; Owrutsky, Jeffrey C.

2013-01-01

Highlights: ► Static and transient infrared spectroscopy of pseudohalide bipyridine ruthenium complexes. ► Vibrational energy relaxes faster for the azide than the thiocyanate and cyanide analogs. ► Intramolecular vibrational relaxation is prevalent in cis-Ru(bpy) 2 (N 3 ) 2 . - Abstract: Static and transient infrared spectroscopy were used to investigate cis-Ru(bpy) 2 (N 3 ) 2 (bpy = 2,2′-bipyridine), cis-Ru(bpy) 2 (NCS) 2 , and cis-Ru(bpy) 2 (CN) 2 in solution. The NC stretching IR band for cis-Ru(bpy) 2 (NCS) 2 appears at higher frequency (∼2106 cm −1 in DMSO) than for the free NCS − anion while the IR bands for the azide and cyanide complexes are closer to those of the respective free anions. The vibrational energy relaxation (VER) lifetime for the azide complex is found to be much shorter (∼5 ps) than for either the NCS or CN species (both ∼70 ps in DMSO) and the lifetimes resemble those for each corresponding free anion in solution. However, for cis-Ru(bpy) 2 (N 3 ) 2 , it is determined that the transition frequency depends more on the solvent than the VER lifetime implying that intramolecular vibrational relaxation is predominant over solvent energy-extracting interactions. These results are compared to the behavior of other related metal complexes in solution

Infrared spectroscopy of the ν1 + ν4 and 3ν4 bands of the nitrate radical

Science.gov (United States)

Kawaguchi, Kentarou; Fujimori, Ryuji; Ishiwata, Takashi

2018-05-01

High-resolution Fourier transform infrared spectra of the ν1 + ν4 and 3ν4 bands of 14NO3 were observed in the 1414 and 1174 cm-1 regions, respectively, and the corresponding ones of 15NO3 in the 1407 and 1159 cm-1 regions, respectively, and analyzed as E‧-A2‧ bands. The rotational constants of the upper states of 14NO3 are determined to be 0.457584 and 0.46089 cm-1 for ν1 + ν4 and 3ν4, respectively, consistent with the vibrational assignment. Effective Coriolis coupling constants of the ground electronic state are partly explained by vibronic interaction from the B2E‧ state, and a large change (37% decrease) in the value of the ν1 + ν4 state compared with that of the ν4 state is attributed to a mixing with the ν3 + ν4 state (1492 cm-1) through vibrational anharmonicity.

Rotational Spectrum and Internal Rotation Barrier of 1-Chloro-1,1-difluoroethane

Science.gov (United States)

Alonso, José L.; López, Juan C.; Blanco, Susana; Guarnieri, Antonio

1997-03-01

The rotational spectra of 1-chloro-1,1-difluoroethane (HCFC-142b) has been investigated in the frequency region 8-115 GHz with Stark, waveguide Fourier transform (FTMW), and millimeter-wave spectrometers. Assignments in large frequency regions with the corresponding frequency measurements have been made for the ground andv18= 1 (CH3torsion) vibrational states of the35Cl isotopomer and for the ground state of the37Cl species. Accurate rotational, quartic centrifugal distortion, and quadrupole coupling constants have been determined from global fits considering all these states. SmallA-Einternal rotation splittings have been observed for thev18= 1 vibrational state using FTMW spectroscopy. The barrier height for the internal rotation of the methyl group has been determined to be 3751 (4) cal mol-1, in disagreement with the previous microwave value of 4400 (100) cal mol-1reported by G. Graner and C. Thomas [J. Chem. Phys.49,4160-4167 (1968)].

RF discharge slab carbon monoxide laser: overtone lasing (2.5-4.0 micron) and fundamental band tuning (5.0-6.5 micron)

Science.gov (United States)

Ionin, Andrey A.; Kozlov, Andrey Yu.; Seleznev, Leonid V.; Sinitsyn, Dmitry V.

2008-10-01

Overtone lasing and fundamental band tuning was for the first time obtained in a slab carbon monoxide laser. The compact slab CO laser with active volume 3×30×250 mm3 was excited by a repetitively pulsed capacitive RF discharge (81.36 MHz) with pulse repetition rate 100-500 Hz. The laser electrodes were cooled down to 120 K. Gas mixture CO:Air:He at gas pressures 15-22 Torr was used. An optical scheme "frequency selective master oscillator - laser amplifier" was applied for getting fundamental band tuning. Single line lasing with average power up to several tens of mW was observed on ~100 rotational-vibrational transitions of CO molecule within the spectral range ~5.0 - 6.5 micron. Multiline overtone lasing was observed on ~80 spectral lines within the spectral range ~2.5 -4.0 micron, with maximum single line average output power 12 mW. Total output power of the slab overtone CO laser came up to 0.3 W, with maximum laser efficiency 0.5%. Results of parametric studies of the overtone CO laser including complicated time behavior for laser pulses on different overtone vibrational-rotational transitions are discussed.

Critical evaluation of measured rotational-vibrational transitions of four sulphur isotopologues of S16O2

Science.gov (United States)

Tóbiás, Roland; Furtenbacher, Tibor; Császár, Attila G.; Naumenko, Olga V.; Tennyson, Jonathan; Flaud, Jean-Marie; Kumar, Praveen; Poirier, Bill

2018-03-01

A critical evaluation and validation of the complete set of previously published experimental rotational-vibrational line positions is reported for the four stable sulphur isotopologues of the semirigid SO2 molecule - i.e., 32S16O2, 33S16O2, 34S16O2, and 36S16O2. The experimentally measured, assigned, and labeled transitions are collated from 43 sources. The 32S16O2, 33S16O2, 34S16O2, and 36S16O2 datasets contain 40,269, 15,628, 31,080, and 31 lines, respectively. Of the datasets collated, only the extremely limited 36S16O2 dataset is not subjected to a detailed analysis. As part of a detailed analysis of the experimental spectroscopic networks corresponding to the ground electronic states of the 32S16O2, 33S16O2, and 34S16O2 isotopologues, the MARVEL (Measured Active Rotational-Vibrational Energy Levels) procedure is used to determine the rovibrational energy levels. The rovibrational levels and their vibrational parent and asymmetric-top quantum numbers are compared to ones obtained from accurate variational nuclear-motion computations as well as to results of carefully designed effective Hamiltonian models. The rovibrational energy levels of the three isotopologues having the same labels are also compared against each other to ensure self-consistency. This careful, multifaceted analysis gives rise to 15,130, 5852, and 10,893 validated rovibrational energy levels, with a typical accuracy of a few 0.0001 cm-1 , for 32S16O2, 33S16O2, and 34S16O2, respectively. The extensive list of validated experimental lines and empirical (MARVEL) energy levels of the S16O2 isotopologues studied are deposited in the Supplementary Material of this article, as well as in the distributed information system ReSpecTh (http://respecth.hu).

Dynamic modelling and control of a rotating Euler-Bernoulli beam

Science.gov (United States)

Yang, J. B.; Jiang, L. J.; Chen, D. CH.

2004-07-01

Flexible motion of a uniform Euler-Bernoulli beam attached to a rotating rigid hub is investigated. Fully coupled non-linear integro-differential equations, describing axial, transverse and rotational motions of the beam, are derived by using the extended Hamilton's principle. The centrifugal stiffening effect is included in the derivation. A finite-dimensional model, including couplings of axial and transverse vibrations, and of elastic deformations and rigid motions, is obtained by the finite element method. By neglecting the axial motion, a simplified modelling, suitable for studying the transverse vibration and control of a beam with large angle and high-speed rotation, is presented. And suppressions of transverse vibrations of a rotating beam are simulated with the model by combining positive position feedback and momentum exchange feedback control laws. It is indicated that an improved performance for vibration control can be achieved with the method.

IUPAC critical evaluation of the rotational-vibrational spectra of water vapor. Part II

International Nuclear Information System (INIS)

Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Csaszar, Attila G.; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Toth, Robert A.; Vandaele, Ann Carine; Zobov, Nikolai F.; Fally, Sophie; Fazliev, Alexander Z.; Furtenbacher, Tibor; Gordon, Iouli E.; Hu, Shui-Ming

2010-01-01

This is the second of a series of articles reporting critically evaluated rotational-vibrational line positions, transition intensities, pressure dependences, and energy levels, with associated critically reviewed assignments and uncertainties, for all the main isotopologues of water. This article presents energy levels and line positions of the following singly deuterated isotopologues of water: HD 16 O, HD 17 O, and HD 18 O. The MARVEL (measured active rotational-vibrational energy levels) procedure is used to determine the levels, the lines, and their self-consistent uncertainties for the spectral regions 0-22 708, 0-1674, and 0-12 105 cm -1 for HD 16 O, HD 17 O, and HD 18 O, respectively. For HD 16 O, 54 740 transitions were analyzed from 76 sources, the lines come from spectra recorded both at room temperature and from hot samples. These lines correspond to 36 690 distinct assignments and 8818 energy levels. For HD 17 O, only 485 transitions could be analyzed from three sources; the lines correspond to 162 MARVEL energy levels. For HD 18 O, 8729 transitions were analyzed from 11 sources and these lines correspond to 1864 energy levels. The energy levels are checked against ones determined from accurate variational nuclear motion computations employing exact kinetic energy operators. This comparison shows that the measured transitions account for about 86% of the anticipated absorbance of HD 16 O at 296 K and that the transitions predicted by the MARVEL energy levels account for essentially all the remaining absorbance. The extensive list of MARVEL lines and levels obtained are given in the Supplementary Material of this article, as well as in a distributed information system applied to water, W-DIS, where they can easily be retrieved. In addition, the transition and energy level information for H 2 17 O and H 2 18 O, given in the first paper of this series [Tennyson, et al. J Quant Spectr Rad Transfer 2009;110:573-96], has been updated.

Rotation in a gravitational billiard

Science.gov (United States)

Peraza-Mues, G. G.; Carvente, Osvaldo; Moukarzel, Cristian F.

Gravitational billiards composed of a viscoelastic frictional disk bouncing on a vibrating wedge have been studied previously, but only from the point of view of their translational behavior. In this work, the average rotational velocity of the disk is studied under various circumstances. First, an experimental realization is briefly presented, which shows sustained rotation when the wedge is tilted. Next, this phenomenon is scrutinized in close detail using a precise numerical implementation of frictional forces. We show that the bouncing disk acquires a spontaneous rotational velocity whenever the wedge angle is not bisected by the direction of gravity. Our molecular dynamics (MD) results are well reproduced by event-driven (ED) simulations. When the wedge aperture angle θW>π/2, the average tangential velocity Rω¯ of the disk scales with the typical wedge vibration velocity vb, and is in general a nonmonotonic function of the overall tilt angle θT of the wedge. The present work focuses on wedges with θW=2π/3, which are relevant for the problem of spontaneous rotation in vibrated disk packings. This study makes part of the PhD Thesis of G. G. Peraza-Mues.

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.

Rotational seismology

Science.gov (United States)

Lee, William H K.

2016-01-01

Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

Examination of a failed reactor coolant pump rotating assembly from Crystal River Unit 3

International Nuclear Information System (INIS)

Hayner, G.O.; Lubnow, T.; Clary, M.

1990-01-01

On January 18, 1989, the A reactor coolant pump rotating assembly at the Crystal River Unit 3 Nuclear Power Plant failed during operation. A rotating assembly from this pump had previously failed in 1986. The reactor coolant pump was fabricated by Byron Jackson Pump Division of Borg-Warner Ind. Products, Inc. from UNS S66286 superalloy (Alloy A286). A root cause failure analysis examination was performed on the pump shaft and other components. The failure analysis included shaft vibrational mode and stress analyses, pump clearance and alignment analyses, and detailed destructive examination of the shaft and hydrostatic bearing assemblies. Based on the detailed physical examination of the shaft it was concluded that cracks initiated in the pump shaft at two sites approximately 180 0 apart in a band of shallow, thermally induced fatigue cracks. The cracks initiated at the bottom edge of the motor end shrink fit pad under the shrink fit sleeve supporting the hydrostatic bearing journal. The band of thermally induced fatigue cracks was apparently caused by mixing of cold seal injection water and hot reactor coolant in gaps between the pump shaft and sleeve. The motor end shrink fit was apparently not effective in preventing introduction of the seal injection water to this area. Initial crack propagation occurred by fatigue due to lateral vibration; however, the majority of crack propagation occurred by abnormal torsional fatigue loading induced by contact and sticking between the rotating and stationary portions of the hydrostatic bearing. Final fracture of the shaft occurred by torsional overload. Metallurgical characteristics and mechanical properties of the shaft were within design specification and probably did not significantly influence the cracking process

Toward yrast spectroscopy in soft vibrational nuclei

International Nuclear Information System (INIS)

Marumori, Toshio; Kuriyama, Atsushi; Sakata, Fumihiko.

1979-10-01

In a formally parallel way with that exciting progress has been recently achieved in understanding the yrast spectra of the rotational nuclei in terms of the quasi-particle motion in the rotating frame, an attempt to understand the yrast spectra of the vibrational nuclei in terms of the quasi-particle motion is proposed. The essential idea is to introduce the quasi-particle motion in a generalized vibrating frame, which can be regarded as a rotating frame in the gauge space of ''physical'' phonons where the number of the physical phonons plays the role of the angular momentum. On the basis of a simple fundamental principle called as the ''invariance principle of the Schroedinger equation'', which leads us to the ''maximal decoupling'' between the physical phonon and the intrinsic modes, it is shown that the vibrational frame as well as the physical-phonon-number operator represented by the quasi-particles can be self-consistently determined. A new scope toward the yrast spectroscopy of the vibrational nuclei in terms of the quasi-particle motion is discussed. (author)

Enhancement of Faraday rotation at photonic-band-gap edge in garnet-based magnetophotonic crystals

International Nuclear Information System (INIS)

Zhdanov, A.G.; Fedyanin, A.A.; Aktsipetrov, O.A.; Kobayashi, D.; Uchida, H.; Inoue, M.

2006-01-01

Spectral dependences of Faraday rotation angle in one-dimensional garnet-based magnetophotonic crystals are considered. The enhancement of Faraday angle is demonstrated at the photonic band gap (PBG) edge both theoretically and experimentally. It is shown to be associated with the optical field localization in the magnetic layers of the structure. The advantages of magnetophotonic crystals in comparison with traditional magnetic microcavities are discussed. The specially designed microcavity structures optimized for the Faraday effect enhancement at the PBG edge are suggested

Flow induced vibrations of the CLIC X-Band accelerating structures

CERN Document Server

Charles, Tessa; Boland, Mark; Riddone, Germana; Samoshkin, Alexandre

2011-01-01

Turbulent cooling water in the Compact Linear Collider (CLIC) accelerating structures will inevitably induce some vibrations. The maximum acceptable amplitude of vibrations is small, as vibrations in the accelerating structure could lead to beam jitter and alignment difficulties. A Finite Element Analysis model is needed to identify the conditions under which turbulent instabilities and significant vibrations are induced. Due to the orders of magnitude difference between the fluid motion and the structure’s motion, small vibrations of the structure will not contribute to the turbulence of the cooling fluid. Therefore the resonant conditions of the cooling channels presented in this paper, directly identify the natural frequencies of the accelerating structures to be avoided under normal operating conditions. In this paper a 2D model of the cooling channel is presented finding spots of turbulence being formed from a shear layer instability. This effect is observed through direct visualization and wavelet ana...

Nonlinear Response of Vibrational Conveyers with Nonideal Vibration Exciter: Superharmonic and Subharmonic Resonance

Directory of Open Access Journals (Sweden)

H. Bayıroğlu

2012-01-01

Full Text Available Vibrational conveyers with a centrifugal vibration exciter transmit their load based on the jumping method. Common unbalanced-mass driver oscillates the trough. The motion is strictly related to the vibrational parameters. The transition over resonance of a vibratory system, excited by rotating unbalances, is important in terms of the maximum vibrational amplitude produced and the power demand on the drive for the crossover. The mechanical system is driven by the DC motor. In this study, the working ranges of oscillating shaking conveyers with nonideal vibration exciter have been analyzed analytically for superharmonic and subharmonic resonances by the method of multiple scales and numerically. The analytical results obtained in this study agree well with the numerical results.

Electromagnetic harvester for lateral vibration in rotating machines

Science.gov (United States)

de Araujo, Marcus Vinícius Vitoratti; Nicoletti, Rodrigo

2015-02-01

Energy harvesters are devices that convert mechanical energy, usually vibration, into electrical energy that can be used to supply low power circuits (e.g. sensors). In this work, an energy harvester is designed for converting the mechanical energy of the lateral vibrations of shafts into electrical energy. For that, permanent magnets are mounted in the shaft and coils are mounted in a fixed structure. A configuration analysis is performed to find the appropriated polarization of the magnets and orientation of the coils in order to have electromagnetic induction without resisting torque on the shaft. Experimental tests are done for different electrical configurations of the coils: independent, in series and, in parallel. The results show that more electric power is induced when the coils are connected in series, and vibration reduction is more evident when the coils are connected independently.

Vibrational and electronic spectroscopic studies of melatonin

Science.gov (United States)

Singh, Gurpreet; Abbas, J. M.; Dogra, Sukh Dev; Sachdeva, Ritika; Rai, Bimal; Tripathi, S. K.; Prakash, Satya; Sathe, Vasant; Saini, G. S. S.

2014-01-01

We report the infrared absorption and Raman spectra of melatonin recorded with 488 and 632.8 nm excitations in 3600-2700 and 1700-70 cm-1 regions. Further, we optimized molecular structure of the three conformers of melatonin within density functional theory calculations. Vibrational frequencies of all three conformers have also been calculated. Observed vibrational bands have been assigned to different vibrational motions of the molecules on the basis of potential energy distribution calculations and calculated vibrational frequencies. Observed band positions match well with the calculated values after scaling except Nsbnd H stretching mode frequencies. It is found that the observed and calculated frequencies mismatch of Nsbnd H stretching is due to intermolecular interactions between melatonin molecules.

ExoMol line lists - XXIX. The rotation-vibration spectrum of methyl chloride up to 1200 K

Science.gov (United States)

Owens, A.; Yachmenev, A.; Thiel, W.; Fateev, A.; Tennyson, J.; Yurchenko, S. N.

2018-06-01

Comprehensive rotation-vibration line lists are presented for the two main isotopologues of methyl chloride, 12CH335Cl and 12CH337Cl. The line lists, OYT-35 and OYT-37, are suitable for temperatures up to T = 1200 K and consider transitions with rotational excitation up to J = 85 in the wavenumber range 0-6400 cm-1 (wavelengths λ > 1.56 μm). Over 166 billion transitions between 10.2 million energy levels have been calculated variationally for each line list using a new empirically refined potential energy surface, determined by refining to 739 experimentally derived energy levels up to J = 5, and an established ab initio dipole moment surface. The OYT line lists show excellent agreement with newly measured high-temperature infrared absorption cross-sections, reproducing both strong and weak intensity features across the spectrum. The line lists are available from the ExoMol database and the CDS database.

Lock threshold deterioration induced by antenna vibration and signal coupling effects in hypersonic vehicle carrier tracking system of Ka band

Directory of Open Access Journals (Sweden)

Congying ZHU

2018-04-01

Full Text Available The envelope of a hypersonic vehicle is affected by severe fluctuating pressure, which causes the airborne antenna to vibrate slightly. This vibration mixes with the transmitted signals and thus introduces additional multiplicative phase noise. Antenna vibration and signal coupling effects as well as their influence on the lock threshold of the hypersonic vehicle carrier tracking system of the Ka band are investigated in this study. A vibration model is initially established to obtain phase noise in consideration of the inherent relationship between vibration displacement and electromagnetic wavelength. An analytical model of the Phase-Locked Loop (PLL, which is widely used in carrier tracking systems, is established. The coupling effects on carrier tracking performance are investigated and quantitatively analyzed by imposing the multiplicative phase noise on the PLL model. Simulation results show that the phase noise presents a Gaussian distribution and is similar to vibration displacement variation. A large standard deviation in vibration displacement exerts a significant effect on the lock threshold. A critical standard deviation is observed in the PLL of Binary Phase Shift Keying (BPSK and Quadrature Phase Shift Keying (QPSK signals. The effect on QPSK signals is more severe than that on BPSK signals. The maximum tolerable standard deviations normalized by the wavelength of the carrier are 0.04 and 0.02 for BPSK and QPSK signals, respectively. With these critical standard deviations, lock thresholds are increased from −12 and −4 dB to 3 and −2 dB, respectively. Keywords: Antenna vibration, Carrier tracking performance, Lock threshold, Phase locked loop, Tracking Telemetry and Command (TT&C signals

Band Saw Blade Crack before and after Comparison and Analysis of Experiments (2

Directory of Open Access Journals (Sweden)

Gao Jin-gui

2016-01-01

Full Text Available Based on MJ3310 woodworking band saw machine as the research object, under the no-load and load of Vib system vibration signal acquisition, processing and analysis software of band saw blade transverse vibration test and the signal acquisition and analysis of the collected signals obtained: to determine the transverse vibration displacement 5.66μm ~ 7.86μm and the main vibration frequency between 624 Hz ~ 792 Hz, then saw blade crack at least 3 mm, need timely saw blade, cutting high hardness of wood band saw blade transverse vibration displacement and frequency will increase sharply. Can be generated according to the band saw blade crack before and after the changing rule of the horizontal vibration displacement and frequency of transverse vibration and scope, judgment and replacement time of saw blade saw blade defect types, which can fully rational utilization of saw blade work effectively.

Quantum-mechanical theory for electronic-vibrational-rotational energy transfer in atom--diatom collisions: Analysis of the Hamiltonian

International Nuclear Information System (INIS)

Bellum, J.C.; McGuire, P.

1983-01-01

We investigate forms of the molecular system Hamiltonian valid for rigorous quantum-mechanical treatments of inelastic atom--diatom collisions characterized by exchange of energy between electronic, vibrational, and rotational degrees of freedom. We analyze this Hamiltonian in terms of various choices of independent coordinates which unambiguously specify the electronic and nuclear positions in the context of space-fixed and body-fixed reference frames. In particular we derive forms of the Hamiltonian in the context of the following four sets of independent coordinates: (1) a so-called space-fixed set, in which both electronic and nuclear positions are relative to the space-fixed frame; (2) a so-called mixed set, in which nuclear positions are relative to the body-fixed frame while electronic positions are relative to the space-fixed frame; (3) a so-called body-fixed set, in which both electronic and nuclear positions are relative to the body-fixed frame; and (4) another mixed set, in which nuclear positions are relative to the space-fixed frame while electronic positions are relative to the body-fixed frame. Based on practical considerations in accounting for electronic structure and nonadiabatic coupling of electronic states of the collision complex we find the forms of the Hamiltonian in the context of coordinate sets (3) and (4) above to be most appropriate, respectively, for body-fixed and space-fixed treatments of nuclear dynamics in collisional transfer of electronic, vibrational, and rotational energies

Analysis of nonlinear vibrations and stability of rotating asymmetrical nano-shafts incorporating surface energy effects

Science.gov (United States)

Ghodousi, Maryam; Shahgholi, Majid; Payganeh, Gholamhassan

2018-03-01

The objective of the present work is to investigate the nonlinear vibrations of the rotating asymmetrical nano-shafts by considering surface effect. In order to compute the surface stress tensor, the surface elasticity theory is used. The governing nonlinear equations of motion are obtained with the aid of variational approach. Bubnov-Galerkin is a very effective method for exploiting the reduced-order model of the equations of motion. The averaging method is employed to analyze the reduced-order model of the system. For this purpose, the well-known Van der Pol transformation in the complex form and angle-action transformation are utilized. The effect of surface stress on the forward and backward speeds, steady state responses of the system, fixed points, close orbits and stability of the solutions is examined. The preliminary results of the research show that the absolute values of forward and backward whirling speeds in the presence of surface effect with positive residual surface stress are higher than those of regarding the system without surface effect and in the presence of surface effect with negative residual surface stress. In addition, it is seen that the undamped rotating asymmetrical nano-shaft, for specified value of detuning parameter, in the absence or presence of surface effect has various number of stable and unstable periodic solutions. Besides, there is different number of separatrix (homoclinic orbit type). Furthermore, bifurcations, number of solutions and their stability for damped rotating asymmetrical nano-shaft are investigated. Also, the above results have been obtained for rotating symmetrical nano-shaft.

Rotational and vibrational spectra of ethynol from quantum-mechanical calculations

Science.gov (United States)

Defrees, D. J.; Mclean, A. D.

1982-01-01

It is noted that ethynol (HCCOH), despite the theoretical prediction of its stability to tautomerization to ketene, has thus far not been observed. It is shown here that the identification of this unknown molecule, both in space and in the laboratory, can be aided by an ab initio calculation of spectroscopic parameters. At the HF/3-21G level, harmonic vibrational frequencies are computed by way of analytic second differentiation of the Hartee-Fock (HF) energy with respect to the nuclear coordinates. After applying an empirical scale factor, the resultant frequencies are (per cm) 473, 517, 773, 841, 1003, 1217, 2206, 3285, and 3418. The computed dipole moment at the CISD/DZ+P level is 1.79 D. At the CISD+Q/DZ+P level, the molecule's rotational constants are determined. After scaling by empirical correction factors, they are used in deriving the 4(04) - 3(03) frequency of 76.81 + or - 0.3 GHz with a triplet splitting of 0.30 + or - 0.01 GHz. The triplet splitting involves 4(14) - 3(13) and 4(13) - 3(12) relative to the 4(04) - 3(03) transition as the central line.

New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium

Directory of Open Access Journals (Sweden)

K. S. Kalogerakis

2018-01-01

Full Text Available The question of whether mesospheric OH(v rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH(v rotational temperatures as a function of vibrational excitation. Laboratory experiments provided information on rotational energy transfer and direct evidence for fast multi-quantum OH(high-v vibrational relaxation by O atoms. We examine the relationship of the new relaxation pathways with the behavior exhibited by OH(v rotational population distributions. Rapid OH(high-v + O multi-quantum vibrational relaxation connects high and low vibrational levels and enhances the hot tail of the OH(low-v rotational distributions. The effective rotational temperatures of mesospheric OH(v are found to deviate from local thermodynamic equilibrium for all observed vibrational levels. Dedicated to Tom G. Slanger in celebration of his 5 decades of research in aeronomy.

Rotational gait patterns in children and adolescents following tension band plating of idiopathic genua valga.

Science.gov (United States)

Farr, Sebastian; Kranzl, Andreas; Hahne, Julia; Ganger, Rudolf

2017-08-01

Literature suggests that children and adolescents with idiopathic genua valga present with considerable gait deviations in frontal and transverse planes, including altered frontal knee moments, reduced external knee rotation, and increased external hip rotation. This study aimed to evaluate gait parameters in these patients after surgical correction using tension band plating (TBP). We prospectively evaluated 24 consecutive, skeletally immature patients, who received full-length standing radiographs and three-dimensional gait analysis before and after correction, and compared the results observed to a group of 11 typically developing peers. Prior to TBP the cohort showed significantly decreased (worse) internal frontal knee moments compared to the control group. After axis correction the mean and maximum knee moments changed significantly into normalized knee moments (p gait. In addition, the effect of transverse plane changes on knee moments in patients with restored, straight limb axis was calculated. Hence, patients with restored alignment but persistence of decreased external knee rotation demonstrated significantly greater knee moments than those without rotational abnormalities (p = 0.001). This study found that frontal knee moments during gait normalized in children with idiopathic genua valga after surgery. However, decreased external knee rotation and increased external hip rotation during gait persisted in the study cohort. Despite radiological correction, decreased external rotation during gait was associated with increases in medial knee loading. Surgical correction for children with genua valga but normal knee moments may be detrimental, due to redistribution of dynamic knee loading into the opposite joint compartment. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1617-1624, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

The vibrational behaviour of a cracked turbine rotor

International Nuclear Information System (INIS)

Grabowski, B.

1978-01-01

In order to detect an incipient crack on a turbine rotor with the aid of measurement of the shaft vibrations, these must be known in the first place the effects of a crack on the vibrational behavior of a rotor. For this purpose a method using the modal analysis is presented here. The rigidity depending on the angle of rotation at the position of the crack is accounted for by means of a model. Because of the composition of the computer code there may also be worked with measured values for the rigidity. The results of the calculations show that within the range of speeds, in which for many turbines the operating speed lies, a crack will cause distinct variations of the shaft vibrations. The crack stimulates vibrations with frequencies of rotation and frequencies of double-rotation. Both may be used for crack detection. Because of the strong dependence of the size of the amplitudes of vibration on the design of the rotor and the position of the crack each rotor should be subject to a detailed crack calculation for a better judgement of the measured values. (orig.) [de

Large electron transfer rate effects from the Duschinsky mixing of vibrations

DEFF Research Database (Denmark)

Sando, Gerald M.; Spears, Kenneth G; Hupp, Joseph T

2001-01-01

vibrations are very important. The Duschinsky effect arises when two electronic states have vibrational normal mode coordinate systems that are rotated and translated relative to each other. We use a conventional quantum rate model for ET, and the examples include 6-8 vibrations, where two vibrational modes...... are mixed with different amounts of coordinate rotation. The multidimensional Franck-Condon factors (FCF) are computed with standard algorithms and recently developed recursion relations. When displaced, totally symmetric modes are involved, rates with Duschinsky mixing can increase several orders...

Comparison of sEMG processing methods during whole-body vibration exercise.

Science.gov (United States)

Lienhard, Karin; Cabasson, Aline; Meste, Olivier; Colson, Serge S

2015-12-01

The objective was to investigate the influence of surface electromyography (sEMG) processing methods on the quantification of muscle activity during whole-body vibration (WBV) exercises. sEMG activity was recorded while the participants performed squats on the platform with and without WBV. The spikes observed in the sEMG spectrum at the vibration frequency and its harmonics were deleted using state-of-the-art methods, i.e. (1) a band-stop filter, (2) a band-pass filter, and (3) spectral linear interpolation. The same filtering methods were applied on the sEMG during the no-vibration trial. The linear interpolation method showed the highest intraclass correlation coefficients (no vibration: 0.999, WBV: 0.757-0.979) with the comparison measure (unfiltered sEMG during the no-vibration trial), followed by the band-stop filter (no vibration: 0.929-0.975, WBV: 0.661-0.938). While both methods introduced a systematic bias (P interpolation method and the band-stop filter was comparable. The band-pass filter was in poor agreement with the other methods (ICC: 0.207-0.697), unless the sEMG(RMS) was corrected for the bias (ICC ⩾ 0.931, %LOA ⩽ 32.3). In conclusion, spectral linear interpolation or a band-stop filter centered at the vibration frequency and its multiple harmonics should be applied to delete the artifacts in the sEMG signals during WBV. With the use of a band-stop filter it is recommended to correct the sEMG(RMS) for the bias as this procedure improved its performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fault Severity Estimation of Rotating Machinery Based on Residual Signals

Directory of Open Access Journals (Sweden)

Fan Jiang

2012-01-01

Full Text Available Fault severity estimation is an important part of a condition-based maintenance system, which can monitor the performance of an operation machine and enhance its level of safety. In this paper, a novel method based on statistical property and residual signals is developed for estimating the fault severity of rotating machinery. The fast Fourier transformation (FFT is applied to extract the so-called multifrequency-band energy (MFBE from the vibration signals of rotating machinery with different fault severity levels in the first stage. Usually these features of the working conditions with different fault sensitivities are different. Therefore a sensitive features-selecting algorithm is defined to construct the feature matrix and calculate the statistic parameter (mean in the second stage. In the last stage, the residual signals computed by the zero space vector are used to estimate the fault severity. Simulation and experimental results reveal that the proposed method based on statistics and residual signals is effective and feasible for estimating the severity of a rotating machine fault.

Rotational temperature determinations in molecular gas lasers

International Nuclear Information System (INIS)

Weaver, L.A.; Taylor, L.H.; Denes, L.J.

1975-01-01

The small-signal gain expressions for vibrational-rotational transitions are examined in detail to determine possible methods of extracting the rotational temperature from experimental gain measurements in molecular gas lasers. Approximate values of T/subr/ can be deduced from the rotational quantum numbers for which the P- and R-branch gains are maximum. Quite accurate values of T/subr/ and the population inversion density (n/subv//sub prime/-n/subv//sub double-prime/) can be determined by fitting data to suitably linearized gain relationships, or by performing least-squares fits of the P- and R-branch experimental data to the full gain expressions. Experimental gain measurements for 15 P-branch and 12 R-branch transitions in the 10.4-μm CO 2 band have been performed for pulsed uv-preionized laser discharges in CO 2 : N 2 : He=1 : 2 : 3 mixtures at 600 Torr. These data are subjected to the several gain analyses described herein, yielding a rotational temperature of 401plus-or-minus10 degreeK and an inversion density of (3.77plus-or-minus0.07) times10 17 cm -3 for conditions of maximum gain. These techniques provide accurate values of the gas temperature in molecular gas lasers with excellent temporal and spatial resolution, and should be useful in extending the conversion efficiency and arcing limits of high-energy electrically exc []ted lasers

Scattering transform and LSPTSVM based fault diagnosis of rotating machinery

Science.gov (United States)

Ma, Shangjun; Cheng, Bo; Shang, Zhaowei; Liu, Geng

2018-05-01

This paper proposes an algorithm for fault diagnosis of rotating machinery to overcome the shortcomings of classical techniques which are noise sensitive in feature extraction and time consuming for training. Based on the scattering transform and the least squares recursive projection twin support vector machine (LSPTSVM), the method has the advantages of high efficiency and insensitivity for noise signal. Using the energy of the scattering coefficients in each sub-band, the features of the vibration signals are obtained. Then, an LSPTSVM classifier is used for fault diagnosis. The new method is compared with other common methods including the proximal support vector machine, the standard support vector machine and multi-scale theory by using fault data for two systems, a motor bearing and a gear box. The results show that the new method proposed in this study is more effective for fault diagnosis of rotating machinery.

Evidence for octupole softness of the superdeformed shape from band interactions in sup 193,4 Hg

Energy Technology Data Exchange (ETDEWEB)

Cullen, D.M.; Riley, M.A.; Alderson, A.; Ali, I.; Fallon, P.; Forsyth, P.D.; Hanna, F.; Mullins, S.M.; Roberts, J.W.; Sharpey-Schafer, J.F.; Twin, P.J. (Liverpool Univ. (UK). Oliver Lodge Lab.); Bengtsson, T. (Lund Inst. of Tech. (Sweden). Dept. of Mathematical Physics); Bentley, M.A.; Bruce, A.M.; Simpson, J. (Science and Engineering Research Council, Daresbury (UK). Daresbury Lab.); Nazarewicz, W. (Liverpool Univ. (UK). Oliver Lodge Lab. Politechnika Warszawska (Poland). Inst. Fizyki); Poynter, R.; Regan, P.; Wadsworth, R. (York Univ. (UK). Dept. of Physics); Satula, W. (Warsaw Univ. (Poland). Inst. Fizyki Teoretycznej); Sletten, G. (Niels Bohr Inst., Roskilde (Denmark). Tandem Accelerator Lab.); Wyss, R. (Manne Siegbahn Inst. of Physics, Stockholm (Sweden))

1990-12-24

Three superdeformed (SD) bands have been observed in {sup 194}Hg and four (or five ) SD bands in {sup 193}Hg using the {sup 150}Nd+{sup 48}Ca reaction. All bands except for two in {sup 193}Hg show a steady increase in dynamical moment of inertia J{sup (2)} with rotational frequency. The two exceptional bands form a classical pair of strongly interacting bands. It is suggested that the strong interaction between the bands is caused by a softness to octupole deformation. Evidence is found for the existence of dipole transitions connecting bands of opposite signature in {sup 193}Hg. The strengths of these transitions suggest that they are probably E1 supporting the importance of the role of octupole vibrations. These data suggest the wider importance of octupole softness in enhancing E1 transitions in the SD feeding and decay mechanisms. The spectroscopy of the observed SD bands in {sup 193,4}Hg are discussed in detail and attention is drawn to the 'identical' energies of {gamma}-rays in these isotopes with those in lighter isotopes. The similarities in bands relate to the neutron sub-shell closure for SD nuclei at N=112. (orig.).

Vibration measurements of the Daniel K. Inouye Solar Telescope mount, Coudé rotator, and enclosure assemblies

Science.gov (United States)

McBride, William R.; McBride, Daniel R.

2016-08-01

The Daniel K. Inouye Solar Telescope (DKIST) will be the largest solar telescope in the world, with a 4-meter off-axis primary mirror and 16 meter rotating Coudé laboratory within the telescope pier. The off-axis design requires a mount similar to an 8-meter on-axis telescope. Both the telescope mount and the Coudé laboratory utilize a roller bearing technology in place of the more commonly used hydrostatic bearings. The telescope enclosure utilizes a crawler mechanism for the altitude axis. As these mechanisms have not previously been used in a telescope, understanding the vibration characteristics and the potential impact on the telescope image is important. This paper presents the methodology used to perform jitter measurements of the enclosure and the mount bearings and servo system in a high-noise environment utilizing seismic accelerometers and high dynamic-range data acquisition equipment, along with digital signal processing (DSP) techniques. Data acquisition and signal processing were implemented in MATLAB. In the factory acceptance testing of the telescope mount, multiple accelerometers were strategically located to capture the six axes-of-motion of the primary and secondary mirror dummies. The optical sensitivity analysis was used to map these mirror mount displacements and rotations into units of image motion on the focal plane. Similarly, tests were done with the Coudé rotator, treating the entire rotating instrument lab as a rigid body. Testing was performed by recording accelerometer data while the telescope control system performed tracking operations typical of various observing scenarios. The analysis of the accelerometer data utilized noise-averaging fast Fourier transform (FFT) routines, spectrograms, and periodograms. To achieve adequate dynamic range at frequencies as low as 3Hz, the use of special filters and advanced windowing functions were necessary. Numerous identical automated tests were compared to identify and select the data sets

Vibrational relaxation in OCS mixtures

International Nuclear Information System (INIS)

Simpson, C.J.S.M.; Gait, P.D.; Simmie, J.M.

1976-01-01

Experimental measurements are reported of vibrational relaxation times which may be used to show whether there is near resonant vibration-rotation energy transfer between OCS and H 2 , D 2 or HD. Vibrational relaxation times have been measured in OCS and OCS mixtures over the temperature range 360 to 1000 K using a shock tube and a laser schlieren system. The effectiveness of the additives in reducing the relaxation time of OCS is in the order 4 He 3 He 2 2 and HD. Along this series the effect of an increase in temperature changes from the case of speeding up the rate with 4 He to retarding it with D 2 , HD and H 2 . There is no measurable difference in the effectiveness of n-D 2 and o-D 2 and little, or no, difference between n-H 2 and p-H 2 . Thus the experimental results do not give clear evidence for rotational-vibration energy transfer between hydrogen and OCS. This contrasts with the situation for CO 2 + H 2 mixtures. (author)

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

Model of coupled bands in even-even nuclei

Energy Technology Data Exchange (ETDEWEB)

Nadzhakov, E G; Nozharov, R M; Myankova, G Z; Antonova, V A [Bylgarska Akademiya na Naukite, Sofia. Inst. za Yadrena Izsledvaniya i Yadrena Energetika

1979-01-01

The model is derived in a natural way from the theory of coupled modes. It is based on an expansion of the Hamiltonian in terms of elementary transition operators, including direct rotation-vibration coupling with phonons. The treatment is limited to three types of phonons: ( I = K = 0), S (I = K = 1) and (I = K = 2). The basis of the operators, acting on the ground state is truncated by an inclusion of a reasonable number of phonon states. In the framework of this approximation one may evaluate the matrix elements of the model Hamiltonian and diagonalize it by standard numerical methods to fit the experimental spectrum. The well known picture of band hybridization is obtained as a special case of the model under consideration.

Electro-mechanical coupling of rotating 3D beams

Directory of Open Access Journals (Sweden)

Stoykov S.

2016-01-01

Full Text Available A rotating thin-walled beam with piezoelectric element is analysed. The beam is considered to vibrate in space, hence the longitudinal, transverse and torsional deformations are taken into account. The bending deformations of the beam are modelled by assuming Timoshenko's theory. Torsion is included by considering that the cross section rotates as a rigid body but can deform in longitudinal direction due to warping. The warping function is computed preliminary by the finite element method. The equation of motion is derived by the principle of virtual work and discretized in space by the Ritz method. Electro-mechanical coupling is included in the model by considering the internal electrical energy and the electric charge output. The piezo-electric constitutive relations are used in reduced form. The beam is assumed to rotate about a fixed axis with constant speed. The equation of motion is derived in rotating coordinate system, but the influence of the rotation of the coordinate system is taken into account through the inertia forces. Results in time domain are presented for different speeds of rotation and frequencies of vibration. The influence of the speed of rotation and of the frequency of vibration on the electrical output is presented and analysed.

Cases of coupled vibrations and prametric instability in rotating machines

OpenAIRE

Luneno, Jean-Claude

2012-01-01

The principal task in this research project was to analyse the causes and consequences of coupled vibrations and parametric instability in hydropower rotors; where both horizontal and vertical machines are involved. Vibration is a well-known undesirable behavior of dynamical systems characterised by persistent periodic, quasi-periodic or chaotic motions. Vibrations generate noise and cause fatigue, which initiates cracks in mechanical structures. Motions coupling can in some cases augment the...

Nozzle Flow with Vibrational Nonequilibrium. Ph.D. Thesis

Science.gov (United States)

Landry, John Gary

1995-01-01

Flow of nitrogen gas through a converging-diverging nozzle is simulated. The flow is modeled using the Navier-Stokes equations that have been modified for vibrational nonequilibrium. The energy equation is replaced by two equations. One equation accounts for energy effects due to the translational and rotational degrees of freedom, and the other accounts for the affects due to the vibrational degree of freedom. The energy equations are coupled by a relaxation time which measures the time required for the vibrational energy component to equilibrate with the translational and rotational energy components. An improved relaxation time is used in this thesis. The equations are solved numerically using the Steger-Warming flux vector splitting method and the Implicit MacCormack method. The results show that uniform flow is produced outside of the boundary layer. Nonequilibrium exists in both the converging and diverging nozzle sections. The boundary layer region is characterized by a marked increase in translational-rotational temperature. The vibrational temperature remains frozen downstream of the nozzle, except in the boundary layer.

Vibration monitoring of EDF rotating machinery using artificial neural networks

International Nuclear Information System (INIS)

Alguindigue, I.E.; Loskiewicz-Buczak, A.; Uhrig, R.E.; Hamon, L.; Lefevre, F.

1991-01-01

Vibration monitoring of components in nuclear power plants has been used for a number of years. This technique involves the analysis of vibration data coming from vital components of the plant to detect features which reflect the operational state of machinery. The analysis leads to the identification of potential failures and their causes, and makes it possible to perform efficient preventive maintenance. Earlydetection is important because it can decrease the probability of catastrophic failures, reduce forced outgage, maximize utilization of available assets, increase the life of the plant, and reduce maintenance costs. This paper documents our work on the design of a vibration monitoring methodology based on neural network technology. This technology provides an attractive complement to traditional vibration analysis because of the potential of neural networks to operate in real-time mode and to handle data which may be distorted or noisy. Our efforts have been concentrated on the analysis and classification of vibration signatures collected by Electricite de France (EDF). Two neural networks algorithms were used in our project: the Recirculation algorithm and the Backpropagation algorithm. Although this project is in the early stages of development it indicates that neural networks may provide a viable methodology for monitoring and diagnostics of vibrating components. Our results are very encouraging

Comparison of rotational temperature derived from ground-based OH airglow observations with TIMED/SABER to evaluate the Einstein Coefficients

Science.gov (United States)

Liu, W.; Xu, J.; Smith, A. K.; Yuan, W.

2017-12-01

Ground-based observations of the OH(9-4, 8-3, 6-2, 5-1, 3-0) band airglows over Xinglong, China (40°24'N, 117°35'E) from December 2011 to 2014 are used to calculate rotational temperatures. The temperatures are calculated using five commonly used Einstein coefficient datasets. The kinetic temperature from TIMED/SABER is completely independent of the OH rotational temperature. SABER temperatures are weighted vertically by weighting functions calculated for each emitting vibrational state from two SABER OH volume emission rate profiles. By comparing the ground-based OH rotational temperature with SABER's, five Einstein coefficient datasets are evaluated. The results show that temporal variations of the rotational temperatures are well correlated with SABER's; the linear correlation coefficients are higher than 0.72, but the slopes of the fit between the SABER and rotational temperatures are not equal to 1. The rotational temperatures calculated using each set of Einstein coefficients produce a different bias with respect to SABER; these are evaluated over each of vibrational levels to assess the best match. It is concluded that rotational temperatures determined using any of the available Einstein coefficient datasets have systematic errors. However, of the five sets of coefficients, the rotational temperature derived with the Langhoff et al.'s (1986) set is most consistent with SABER. In order to get a set of optimal Einstein coefficients for rotational temperature derivation, we derive the relative values from ground-based OH spectra and SABER temperatures statistically using three year data. The use of a standard set of Einstein coefficients will be beneficial for comparing rotational temperatures observed at different sites.

Diagnosis of excessive vibration signals of two-pole generator rotors in balancing

International Nuclear Information System (INIS)

Park, Jong Po

2000-01-01

Cause of excessive vibration with twice the rotational speed of a two-pole generator rotor for the fossil power plants was investigated. The two-pole generator rotor, treated as a typically asymmetric rotor in vibration analysis, produces asynchronous vibration with twice the rotational speed, sub-harmonic critical speeds, and potentially unstable operating zones due to its own inertia and/or stiffness asymmetry. This paper introduces a practical balancing procedure, and presents the results of the investigation on sources of the excessive vibration based on the experimental vibration data of the asymmetric two-pole rotor in balancing

Mixing of ground-state rotational and gamma and beta vibrational bands in the region A>=228

Energy Technology Data Exchange (ETDEWEB)

Mittal, R; Sahota, H S [Punjabi Univ., Patiala (India). Dept. of Physics

1983-06-21

The mixing of beta, gamma and ground-state bands has been investigated through the experimental determination of mixing parameters Zsub(..gamma..) and Zsub(..beta gamma..). These Zsub(..gamma..) values have been compared with the theoretical calculations of this parameter from the solutions of time-dependent HFB equations on the adiabatic and nonadiabatic assumptions. The experimental values are in better agreement with the results obtained under the nonadiabatic assumption, valid for small deviations from the spherical symmetry.

Dynamics of rotating and vibrating thin hemispherical shell with mass and damping imperfections and parametrically driven by discrete electrodes

CSIR Research Space (South Africa)

Shatalov, M

2009-05-01

Full Text Available stream_source_info Shatalov2_2009.pdf.txt stream_content_type text/plain stream_size 22572 Content-Encoding UTF-8 stream_name Shatalov2_2009.pdf.txt Content-Type text/plain; charset=UTF-8 1 DYNAMICS OF ROTATING... AND VIBRATING THIN HEMISPHERICAL SHELL WITH MASS AND DAMPING IMPERFECTIONS AND PARAMETRICALLY DRIVEN BY DISCRETE ELECTRODES Michael Shatalov1,2 and Charlotta Coetzee2 1Sensor Science and Technology (SST) of CSIR Material Science and Manufacturing (MSM...

Analytic description of highly excited vibrational-rotational states of diatomic molecules: II. Application to the hydrogen chloride molecule

International Nuclear Information System (INIS)

Burenin, A.V.; Ryabikin, M.Y.

1995-01-01

Processing of the precise experimental data on transition frequencies and energy levels in the ground electronic state of the H 35 Cl molecule was carried out on the basis of the asymptotically correct perturbation series analytically constructed to describe the discrete vibrational-rotational spectrum of a diatomic molecule. The perturbation series was shown to converge rapidly up to the dissociation energy E D , whereas the conventional Dunham series has a distinct limit of applicability equal to 0.39E D . 12 refs., 2 figs

Investigation of Inertia Welding Process for Applying Gilding Metal Rotating Bands to Projectile, 155-mm, M483A1.

Science.gov (United States)

1978-07-01

AISI 4140 steel body, but additional work remains to be done because pure copper behaves differently than gilding metal when subjected to the inertia...bands to AISI 1340 steel bodies used with the 155-mm, M483A1 Projectile. As a result of the effort it was demon- strated that the process is practical...rotating bands to AISI 1340 steel bodies used with the 155-mm, M483A1 Projectile. As a result of the effort it was demonstrated that the process is

REFIR/BB initial observations in the water vapour rotational band: Results from a field campaign

International Nuclear Information System (INIS)

Esposito, F.; Grieco, G.; Leone, L.; Restieri, R.; Serio, C.; Bianchini, G.; Palchetti, L.; Pellegrini, M.; Cuomo, V.; Masiello, G.; Pavese, G.

2007-01-01

There is a growing interest in the far infrared spectral region 17-50 μm as a remote sensing tool in atmospheric sciences, since this portion of the spectrum contains the characteristic molecular rotational band for water vapour. Much of the Earth energy lost to space is radiated through this spectral region. The Radiation Explorer in the Far InfraRed Breadboard (REFIR/BB) spectrometer was born because of the quest to make observations in the far infrared. REFIR/BB is a Fourier Transform Spectrometer with a sampling resolution of 0.5 cm -1 and it was tested for the first time in the field to check its reliability and radiometric performance. The field campaign was held at Toppo di Castelgrande (40 o 49' N, 15 o 27' E, 1258 m a. s. l.), a mountain site in South Italy. The spectral and radiometric performance of the instrument and initial observations are shown in this paper. Comparisons to both (1) BOMEM MR100 Fourier Transform spectrometer observations and (2) line-by-line radiative transfer calculations for selected clear sky are presented and discussed. These comparisons (1) show a very nice agreement between radiance measured by REFIR/BB and by BOMEM MR100 and (2) demonstrate that REFIR/BB accurately observes the very fine spectral structure in the water vapour rotational band

Coupled channel analysis of the 142Ce (α,α)142Ce* reaction: study of a vibrational-rotational transition nucleus

International Nuclear Information System (INIS)

Appoloni, C.R.

1983-01-01

The angular distribution of the elastic and inelastic scattering of a particles corresponding to the excitation of the low-lying collective states of 142 Ce were measured at an incident energy of 18.0 MeV. The angular distribution of the following excited states were obtained: 641, 1.219, 1.450, 1.536, 1.653, 1.742, 2.004, 2.043, 2.114, 2.125, 2.279, 2.364, 2.542, 2.604 e 3.067 MeV. The angular distributions of the ground state and the first six excited states were analysed within the flamework of the Anharmonic Vibrational and Symmetric Rotational Models, with the Coupled Channel Theory. The Anharmonic Vibrational Model gave the best and most complete description of the experimental data. The wave functions and the deformation parameters of the analysed states were determined. (Author) [pt

Picosecond thermometer in the amide I band of myoglobin

DEFF Research Database (Denmark)

Austin, R.H.; Xie, A.; Meer, L. van der

2005-01-01

The amide I and II bands in myoglobin show a heterogeneous temperature dependence, with bands at 6.17 and 6.43 mu m which are more intense at low temperatures. The amide I band temperature dependence is on the long wavelength edge of the band, while the short wavelength side has almost...... can be used to determine the time it takes vibrational energy to flow into the hydration shell. We determine that vibrational energy flow to the hydration shell from the amide I takes approximately 20 ps to occur....

Monitoring machining conditions by analyzing cutting force vibration

Energy Technology Data Exchange (ETDEWEB)

Piao, Chun Guang; Kim, Ju Wan; Kim, Jin Oh; Shin, Yoan [Soongsl University, Seoul (Korea, Republic of)

2015-09-15

This paper deals with an experimental technique for monitoring machining conditions by analyzing cutting-force vibration measured at a milling machine. This technique is based on the relationship of the cutting-force vibrations with the feed rate and cutting depth as reported earlier. The measurement system consists of dynamic force transducers and a signal amplifier. The analysis system includes an oscilloscope and a computer with a LabVIEW program. Experiments were carried out at various feed rates and cutting depths, while the rotating speed was kept constant. The magnitude of the cutting force vibration component corresponding to the number of cutting edges multiplied by the frequency of rotation was linearly correlated with the machining conditions. When one condition of machining is known, another condition can be identified by analyzing the cutting-force vibration.

Monitoring machining conditions by analyzing cutting force vibration

International Nuclear Information System (INIS)

Piao, Chun Guang; Kim, Ju Wan; Kim, Jin Oh; Shin, Yoan

2015-01-01

This paper deals with an experimental technique for monitoring machining conditions by analyzing cutting-force vibration measured at a milling machine. This technique is based on the relationship of the cutting-force vibrations with the feed rate and cutting depth as reported earlier. The measurement system consists of dynamic force transducers and a signal amplifier. The analysis system includes an oscilloscope and a computer with a LabVIEW program. Experiments were carried out at various feed rates and cutting depths, while the rotating speed was kept constant. The magnitude of the cutting force vibration component corresponding to the number of cutting edges multiplied by the frequency of rotation was linearly correlated with the machining conditions. When one condition of machining is known, another condition can be identified by analyzing the cutting-force vibration

Symbolic derivation of high-order Rayleigh-Schroedinger perturbation energies using computer algebra: Application to vibrational-rotational analysis of diatomic molecules

Energy Technology Data Exchange (ETDEWEB)

Herbert, John M. [Kansas State Univ., Manhattan, KS (United States). Dept. of Chemistry

1997-01-01

Rayleigh-Schroedinger perturbation theory is an effective and popular tool for describing low-lying vibrational and rotational states of molecules. This method, in conjunction with ab initio techniques for computation of electronic potential energy surfaces, can be used to calculate first-principles molecular vibrational-rotational energies to successive orders of approximation. Because of mathematical complexities, however, such perturbation calculations are rarely extended beyond the second order of approximation, although recent work by Herbert has provided a formula for the nth-order energy correction. This report extends that work and furnishes the remaining theoretical details (including a general formula for the Rayleigh-Schroedinger expansion coefficients) necessary for calculation of energy corrections to arbitrary order. The commercial computer algebra software Mathematica is employed to perform the prohibitively tedious symbolic manipulations necessary for derivation of generalized energy formulae in terms of universal constants, molecular constants, and quantum numbers. As a pedagogical example, a Hamiltonian operator tailored specifically to diatomic molecules is derived, and the perturbation formulae obtained from this Hamiltonian are evaluated for a number of such molecules. This work provides a foundation for future analyses of polyatomic molecules, since it demonstrates that arbitrary-order perturbation theory can successfully be applied with the aid of commercially available computer algebra software.

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

Electromagnetic transition probabilities in the natural-parity rotational bands of 155,157Gd

International Nuclear Information System (INIS)

Kusakari, H.; Oshima, M.; Uchikura, A.; Sugawara, M.; Tomotani, A.; Ichikawa, S.; Iimura, H.; Morikawa, T.; Inamura, T.; Matsuzaki, M.

1992-01-01

The ground-state rotational bands of 155 Gd and 157 Gd have been investigated through multiple Coulomb excitation with beams of 240-MeV 58 Ni and 305-MeV 81 Br. Gamma-ray branchings and E2/M1 mixing ratios were determined by γ-ray angular-distribution measurement. Nuclear lifetimes of levels up to I=21/2 and 23/2 for 155,157 Gd, respectively, have been measured using the Doppler-shift recoil-distance method. The observed signature dependence of M1 transition rates was found to be inverted in relation to the quasiparticle energy splitting. The data are analyzed in terms of the cranking model

Rotational excitation of N2 by electron impact: 1-4 eV

International Nuclear Information System (INIS)

Wong, S.F.; Dube, L.

1978-01-01

Rotational and rotational-vibrational (v = 0 → 1) excitation in N 2 have been studied with a crossed-beam electron-impact apparatus. In the energy range 1-4 eV, the elastic and vibrational energy-loss peaks show large rotational broadening compared with the apparatus profile (full width at half-maximum, 18 meV). The branching ratios for rotational transitions with Δj = 0, +- 2, +- 4 are obtained with a line-shape analysis applied to the energy-loss profiles. The results for rotational-vibrational excitation at 2.27 eV and scattering angles 30-90 0 are in good agreement with the calculations using the resonant dπ waves and the rotational impulse approximation. The corresponding results for pure rotational excitation show that the branches with Δj = +- 2 and +- 4 are predominantly excited via resonances, while the branch with Δj = 0 contains a large contribution from direct scattering. The absolute rotational cross sections for Δj = +- 4 are measured; they exhibit a large magnitude (10 -16 cm 2 ) and peak and valley structures in the 1-4 eV range, reminiscent of well-known resonant vibrational excitation. The energy dependence and the absolute magnitude of the rotational cross sections for Δj = +- 4 can be understood in terms of a ''boomerang'' calculation. A comparison of the experiment with the relevant theoretical calculations is made

Size-induced axial band structure and directional flow of a ternary-size granular material in a 3-D horizontal rotating drum

Science.gov (United States)

Yang, Shiliang; Sun, Yuhao; Ma, Honghe; Chew, Jia Wei

2018-05-01

Differences in the material property of the granular material induce segregation which inevitably influences both natural and industrial processes. To understand the dynamical segregation behavior, the band structure, and also the spatial redistribution of particles induced by the size differences of the particles, a ternary-size granular mixture in a three-dimensional rotating drum operating in the rolling flow regime is numerically simulated using the discrete element method. The results demonstrate that (i) the axial bands of the medium particles are spatially sandwiched in between those of the large and small ones; (ii) the total mass in the active and passive regions is a global parameter independent of segregation; (iii) nearly one-third of all the particles are in the active region, with the small particles having the highest mass fraction; (iv) the axial bands initially appear near the end wall, then become wider and purer in the particular species with time as more axial bands form toward the axial center; and (v) the medium particle type exhibits segregation later and has the narrowest axial bandwidth and least purity in the bands. Compared to the binary-size system, the presence of the medium particle type slightly increases the total mass in the active region, leads to larger mass fractions of the small and large particle types in the active region, and enhances the axial segregation in the system. The results obtained in the current work provide valuable insights regarding size segregation, and band structure and formation in the rotating drum with polydisperse particles.

An SVM-Based Classifier for Estimating the State of Various Rotating Components in Agro-Industrial Machinery with a Vibration Signal Acquired from a Single Point on the Machine Chassis

Directory of Open Access Journals (Sweden)

Ruben Ruiz-Gonzalez

2014-11-01

Full Text Available The goal of this article is to assess the feasibility of estimating the state of various rotating components in agro-industrial machinery by employing just one vibration signal acquired from a single point on the machine chassis. To do so, a Support Vector Machine (SVM-based system is employed. Experimental tests evaluated this system by acquiring vibration data from a single point of an agricultural harvester, while varying several of its working conditions. The whole process included two major steps. Initially, the vibration data were preprocessed through twelve feature extraction algorithms, after which the Exhaustive Search method selected the most suitable features. Secondly, the SVM-based system accuracy was evaluated by using Leave-One-Out cross-validation, with the selected features as the input data. The results of this study provide evidence that (i accurate estimation of the status of various rotating components in agro-industrial machinery is possible by processing the vibration signal acquired from a single point on the machine structure; (ii the vibration signal can be acquired with a uniaxial accelerometer, the orientation of which does not significantly affect the classification accuracy; and, (iii when using an SVM classifier, an 85% mean cross-validation accuracy can be reached, which only requires a maximum of seven features as its input, and no significant improvements are noted between the use of either nonlinear or linear kernels.

Millimetre Wave Rotational Spectrum of Glycolic Acid

Science.gov (United States)

Kisiel, Zbigniew; Pszczolkowski, Lech; Bialkowska-Jaworska, Ewa; Charnley, Steven B.

2016-01-01

The pure rotational spectrum of glycolic acid, CH2OHCOOH, was studied in the region 115-318 GHz. For the most stable SSC conformer, transitions in all vibrational states up to 400 cm(exp -1) have been measured and their analysis is reported. The data sets for the ground state, v21 = 1, and v21 = 2 have been considerably extended. Immediately higher in vibrational energy are two triads of interacting vibrational states and their rotational transitions have been assigned and successfully fitted with coupled Hamiltonians accounting for Fermi and Coriolis resonances. The derived energy level spacings establish that the vibrational frequency of the v21 mode is close to 100 cm(exp -1). The existence of the less stable AAT conformer in the near 50 C sample used in our experiment was also confirmed and additional transitions have been measured.

Long-lasting effects of neck muscle vibration and contraction on self-motion perception of vestibular origin.

Science.gov (United States)

Pettorossi, Vito Enrico; Panichi, Roberto; Botti, Fabio Massimo; Biscarini, Andrea; Filippi, Guido Maria; Schieppati, Marco

2015-10-01

To show that neck proprioceptive input can induce long-term effects on vestibular-dependent self-motion perception. Motion perception was assessed by measuring the subject's error in tracking in the dark the remembered position of a fixed target during whole-body yaw asymmetric rotation of a supporting platform, consisting in a fast rightward half-cycle and a slow leftward half-cycle returning the subject to the initial position. Neck muscles were relaxed or voluntarily contracted, and/or vibrated. Whole-body rotation was administered during or at various intervals after the vibration train. The tracking position error (TPE) at the end of the platform rotation was measured during and after the muscle conditioning maneuvers. Neck input produced immediate and sustained changes in the vestibular perceptual response to whole-body rotation. Vibration of the left sterno-cleido-mastoideus (SCM) or right splenius capitis (SC) or isometric neck muscle effort to rotate the head to the right enhanced the TPE by decreasing the perception of the slow rotation. The reverse effect was observed by activating the contralateral muscle. The effects persisted after the end of SCM conditioning, and slowly vanished within several hours, as tested by late asymmetric rotations. The aftereffect increased in amplitude and persistence by extending the duration of the vibration train (from 1 to 10min), augmenting the vibration frequency (from 5 to 100Hz) or contracting the vibrated muscle. Symmetric yaw rotation elicited a negligible TPE, upon which neck muscle vibrations were ineffective. Neck proprioceptive input induces enduring changes in vestibular-dependent self-motion perception, conditional on the vestibular stimulus feature, and on the side and the characteristics of vibration and status of vibrated muscles. This shows that our perception of whole-body yaw-rotation is not only dependent on accurate vestibular information, but is modulated by proprioceptive information related to

Rotor Vibration Reduction via Active Hybrid Bearings

DEFF Research Database (Denmark)

Nicoletti, Rodrigo; Santos, Ilmar

2002-01-01

The use of fluid power to reduce and control rotor vibration in rotating machines is investigated. An active hybrid bearing is studied, whose main objective is to reduce wear and vibration between rotating and stationary machinery parts. By injecting pressurised oil into the oil film, through...... orifices machined in the bearing pads, one can alter the machine dynamic characteristics, thus enhancing its operational range. A mathematical model of the rotor-bearing system, as well as of the hydraulic system, is presented. Numerical results of the system frequency response show good agreement...

Nonadiabatic Response Model of Laser-Induced Ultrafast π-Electron Rotations in Chiral Aromatic Molecules

International Nuclear Information System (INIS)

Kanno, Manabu; Kono, Hirohiko; Fujimura, Yuichi; Lin, Sheng H.

2010-01-01

We theoretically investigated the nonadiabatic couplings between optically induced π-electron rotations and molecular vibrations in a chiral aromatic molecule irradiated by a nonhelical, linearly polarized laser pulse. The results of wave packet dynamics simulation show that the vibrational amplitudes strongly depend on the initial rotation direction, clockwise or counterclockwise, which is controlled by the polarization direction of the incident pulse. This suggests that attosecond π-electron rotations can be observed by spectroscopic detection of femtosecond molecular vibrations.

Millimeterwave spectroscopy of active laser plasmas; the excited vibrational states of HCN

International Nuclear Information System (INIS)

De Lucia, F.C.; Helminger, P.A.

1977-01-01

Millimeter and submillimeter microwave techniques have been used for the spectroscopic study of an HCN laser plasma. Forty-seven rotational transitions in 12 excited vibrational states have been observed. Numerous rotational, vibrational, and perturbation parameters have been calculated from these data. A discussion of experimental techniques is included

Forecasting of resonances vibration equipment with elastic waves coolant and with the external periodic loads on NPP with WWER

International Nuclear Information System (INIS)

Proskuryakov, K.N.; Zaporozhets, M.V.; Fedorov, A.I.

2015-01-01

Forecasting are carried out for external loads in relation to the main circulation circuit - dynamic loads caused by the rotation of the MCP, dynamic loads caused by the earthquake, dynamic loads caused by damage to the MCP in the earthquake. A comparison of the response spectrum of one of the variants of the base of the NPP, with the frequency vibration of the primary circuit equipment for NPP with WWER-1000 and self-frequency of elastic waves in the fluid. Analysis of the comparison results shows that the frequency of vibration of the main equipment of the reactor plant and elastic waves are in the frequency band in the spectrum response corresponding to the maximum amplitude of the seismic action [ru

Control of π-Electron Rotations in Chiral Aromatic Molecules Using Intense Laser Pulses

Science.gov (United States)

Kanno, Manabu; Kono, Hirohiko; Fujimura, Yuichi

Our recent theoretical studies on laser-induced π-electron rotations in chiral aromatic molecules are reviewed. π electrons of a chiral aromatic molecule can be rotated along its aromatic ring by a nonhelical, linearly polarized laser pulse. An ansa aromatic molecule with a six-membered ring, 2,5-dichloro[n](3,6) pyrazinophane, which belongs to a planar-chiral molecule group, and its simplified molecule 2,5-dichloropyrazine are taken as model molecules. Electron wavepacket simulations in the frozen-molecular-vibration approximation show that the initial direction of π-electron rotation depends on the polarization direction of a linearly polarized laser pulse applied. Consecutive unidirectional rotation can be achieved by applying a sequence of linearly polarized pump and dump pulses to prevent reverse rotation. Optimal control simulations of π-electron rotation show that another controlling factor for unidirectional rotation is the relative optical phase between the different frequency components of an incident pulse in addition to photon polarization direction. Effects of nonadiabatic coupling between π-electron rotation and molecular vibrations are also presented, where the constraints of the frozen approximation are removed. The angular momentum gradually decays mainly owing to nonadiabatic coupling, while the vibrational amplitudes greatly depend on their rotation direction. This suggests that the direction of π-electron rotation on an attosecond timescale can be identified by detecting femtosecond molecular vibrations.

Condition monitoring of PARR-1 rotating machines by vibration analysis technique

Directory of Open Access Journals (Sweden)

Qadir Javed

2014-01-01

Full Text Available Vibration analysis is a key tool for preventive maintenance involving the trending and analysis of machinery performance parameters to detect and identify developing problems before failure and extensive damage can occur. A lab-based experimental setup has been established for obtaining fault-free and fault condition data. After this analysis, primary and secondary motor and pump vibration data of the Pakistan Research Reactor-1 were obtained and analyzed. Vibration signatures were acquired in horizontal, vertical, and axial directions. The 48 vibration signatures have been analyzed to assess the operational status of motors and pumps. The vibration spectrum has been recorded for a 2000 Hz frequency span with a 3200 lines resolution. The data collected should be helpful in future Pakistan Research Reactor-1 condition monitoring.

Vibrational lifetimes of protein amide modes

International Nuclear Information System (INIS)

Peterson, K.A.; Rella, C.A.

1995-01-01

Measurement of the lifetimes of vibrational modes in proteins has been achieved with a single frequency infrared pump-probe technique using the Stanford Picosecond Free-electron Laser, These are the first direct measurements of vibrational dynamics in the polyamide structure of proteins. In this study, modes associated with the protein backbone are investigated. Results for the amide I band, which consists mainly of the stretching motion of the carbonyl unit of the amide linkage, show that relaxation from the first vibrational excited level (v=1) to the vibrational ground state (v=0) occurs within 1.5 picoseconds with apparent first order kinetics. Comparison of lifetimes for myoglobin and azurin, which have differing secondary structures, show a small but significant difference. The lifetime for the amide I band of myoglobin is 300 femtoseconds shorter than for azurin. Further measurements are in progress on other backbone vibrational modes and on the temperature dependence of the lifetimes. Comparison of vibrational dynamics for proteins with differing secondary structure and for different vibrational modes within a protein will lead to a greater understanding of energy transfer and dissipation in biological systems. In addition, these results have relevance to tissue ablation studies which have been conducted with pulsed infrared lasers. Vibrational lifetimes are necessary for calculating the rate at which the energy from absorbed infrared photons is converted to equilibrium thermal energy within the irradiated volume. The very fast vibrational lifetimes measured here indicate that mechanisms which involve direct vibrational up-pumping of the amide modes with consecutive laser pulses, leading to bond breakage or weakening, are not valid

Band head spin assignment of superdeformed bands in 133Pr using two-parameter formulae

Science.gov (United States)

Sharma, Honey; Mittal, H. M.

2018-03-01

The two-parameter formulae viz. the power index formula, the nuclear softness formula and the VMI model are adopted to accredit the band head spin (I0) of four superdeformed rotational bands in 133Pr. The technique of least square fitting is used to accredit the band head spin for four superdeformed rotational bands in 133Pr. The root mean deviation among the computed transition energies and well-known experimental transition energies are attained by extracting the model parameters from the two-parameter formulae. The determined transition energies are in excellent agreement with the experimental transition energies, whenever exact spins are accredited. The power index formula coincides well with the experimental data and provides minimum root mean deviation. So, the power index formula is more efficient tool than the nuclear softness formula and the VMI model. The deviation of dynamic moment of inertia J(2) against the rotational frequency is also examined.

Measurement of food texture by an acoustic vibration method

Science.gov (United States)

Sakurai, Naoki; Taniwaki, Mitsuru; Iwatani, Shin-ichiro; Akimoto, Hidemi

2011-09-01

Food texture was measured by a new acoustic vibration method. A piezoelectric sensor sandwiched between a probe and piston was inserted into a food sample by delivery of silicon oil to a cylinder by a pump. Vibration emitted from the food sample on insertion of the probe was monitored by voltage outputs of the sensor. The voltage signals were passed through 19 half octave bands to calculate texture index for each band. The texture index was defined as vibration energy of the probe caused by the food rupture and/or breakage per unit time.

Excited states rotational effects on the behavior of excited molecules

CERN Document Server

Lim, Edward C

2013-01-01

Excited States, Volume 7 is a collection of papers that discusses the excited states of molecules. The first paper reviews the rotational involvement in intra-molecular in vibrational redistribution. This paper analyzes the vibrational Hamiltonian as to its efficacy in detecting the manifestations of intra-molecular state-mixing in time-resolved and time-averaged spectroscopic measurements. The next paper examines the temporal behavior of intra-molecular vibration-rotation energy transfer (IVRET) and the effects of IVRET on collision, reaction, and the decomposition processes. This paper also

Broadband characteristics of vibration energy harvesting using one-dimensional phononic piezoelectric cantilever beams

Energy Technology Data Exchange (ETDEWEB)

Chen Zhongsheng, E-mail: czs_study@sina.com [Key Laboratory of Science and Technology on Integrated Logistics Support, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China); Yang Yongmin; Lu Zhimiao; Luo Yanting [Key Laboratory of Science and Technology on Integrated Logistics Support, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China)

2013-02-01

Nowadays broadband vibration energy harvesting using piezoelectric effect has become a research hotspot. The innovation in this paper is the widening of the resonant bandwidth of a piezoelectric harvester based on phononic band gaps, which is called one-dimensional phononic piezoelectric cantilever beams (PPCBs). Broadband characteristics of one-dimensional PPCBs are analyzed deeply and the vibration band gap can be calculated. The effects of different parameters on the vibration band gap are presented by both numerical and finite element simulations. Finally experimental tests are conducted to validate the proposed method. It can be concluded that it is feasible to use the PPCB for broadband vibration energy harvesting and there should be a compromise among related parameters for low-frequency vibrations.

Broadband characteristics of vibration energy harvesting using one-dimensional phononic piezoelectric cantilever beams

International Nuclear Information System (INIS)

Chen Zhongsheng; Yang Yongmin; Lu Zhimiao; Luo Yanting

2013-01-01

Nowadays broadband vibration energy harvesting using piezoelectric effect has become a research hotspot. The innovation in this paper is the widening of the resonant bandwidth of a piezoelectric harvester based on phononic band gaps, which is called one-dimensional phononic piezoelectric cantilever beams (PPCBs). Broadband characteristics of one-dimensional PPCBs are analyzed deeply and the vibration band gap can be calculated. The effects of different parameters on the vibration band gap are presented by both numerical and finite element simulations. Finally experimental tests are conducted to validate the proposed method. It can be concluded that it is feasible to use the PPCB for broadband vibration energy harvesting and there should be a compromise among related parameters for low-frequency vibrations.

Study of the High Resolution Spectrum of the S18O16O Molecule in the Hot 2ν2 + ν3 - ν2 Band

Science.gov (United States)

Ziatkova, A. G.; Gromova, O. V.; Ulenikov, O. N.

2018-05-01

The hot 2ν2 + ν3 - ν2 hybrid band of the S18O16O molecule is assigned in the range 1800-1900 cm-1 for the first time. The spectrum is analyzed based on the method of combination differences. 56 energy levels (Jmax = 15, {K}a^{max}=12 ) are determined based on the experimental data obtained. Rotational parameters of the (021) vibrational state are determined.

Calculated rotational and vibrational g factors of LiH X ¹S⁺ and evaluation of parameters in radial functions from rotational and vibration-rotational spectra

DEFF Research Database (Denmark)

Sauer, Stephan P. A.; Paidarová, Ivana; Oddershede, Jens

2011-01-01

The vibrational g factor, that is, the nonadiabatic correction to the vibrational reduced mass, of LiH has been calculated for internuclear distances over a wide range. Based on multiconfigurational wave functions with a large complete active space and an extended set of gaussian type basis...

Collective rotation from ab initio theory

International Nuclear Information System (INIS)

Caprio, M.A.; Maris, P.; Vary, J.P.; Smith, R.

2015-01-01

Through ab initio approaches in nuclear theory, we may now seek to quantitatively understand the wealth of nuclear collective phenomena starting from the underlying internucleon interactions. No-core configuration interaction (NCCI) calculations for p-shell nuclei give rise to rotational bands, as evidenced by rotational patterns for excitation energies, electromagnetic moments and electromagnetic transitions. In this review, NCCI calculations of 7–9 Be are used to illustrate and explore ab initio rotational structure, and the resulting predictions for rotational band properties are compared with experiment. We highlight the robustness of ab initio rotational predictions across different choices for the internucleon interaction. (author)

Aircraft gas turbine engine vibration diagnostics

Directory of Open Access Journals (Sweden)

Stanislav Fábry

2017-11-01

Full Text Available In the Czech and Slovak aviation are in service elderly aircrafts, usually produced in former Soviet Union. Their power units can be operated in more efficient way, in case of using additional diagnostic methods that allow evaluating their health. Vibration diagnostics is one of the methods indicating changes of rotational machine dynamics. Ground tests of aircraft gas turbine engines allow vibration recording and analysis. Results contribute to airworthiness evaluation and making corrections, if needed. Vibration sensors distribution, signal recording and processing are introduced in a paper. Recorded and re-calculated vibration parameters are used in role of health indicators.

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.)

Origins of IR Intensity in Overtones and Combination Bands in Hydrogen Bonded Systems

Science.gov (United States)

Horvath, Samantha; McCoy, Anne B.

2010-06-01

As the infrared spectra of an increasing number of hydrogen bonded and ion/water complexes have been investigated experimentally, we find that they often contain bands with significant intensity that cannot be attributed to fundamental transitions. In this talk, we explore several sources of the intensity of these overtone and combination bands. A common source of intensity is mode-mode coupling, as is often seen between the proton transfer coordinate and the associated heavy atom vibration. A second important mechanism involves large changes in the dipole moment due the loss of a hydrogen bond. This results in intense overtone transitions involving non-totally symmetric vibrations as well as the introduction of intense combination bands involving intramolecular bending coupled to hindered rotations. These effects will be discussed in the context of several systems, including the spectra of complexes of argon atoms with {H}_3{O}^+, F^-\\cdotH_2O, Cl^-\\cdotH_2O, protonated water clusters,^a and HOONO. T. Guasco, S. Olesen and M. A. Johnson, private communication S. Horvath, A. B. McCoy, J. R. Roscioli and M. A. Johnson, J. Phys. Chem. A, 112, 12337-44 (2008) S. Horvath, A. B. McCoy, B. M. Eliot, G. H. Weddle, J. R. Roscioli and M. A. Johnson, J. Phys. Chem. A, 115, 1556-68 (2010). A. B. McCoy, M. K. Sprague and M. Okumura, J. Phys. Chem. A, 115, 1324-33 (2010)

Strongly coupled rotational band in ${}^{33}\mathrm{Mg}$

Energy Technology Data Exchange (ETDEWEB)

Richard, A. L.; Crawford, H. L.; Fallon, P.; Macchiavelli, A. O.; Bader, V. M.; Bazin, D.; Bowry, M.; Campbell, C. M.; Carpenter, M. P.; Clark, R. M.; Cromaz, M.; Gade, A.; Ideguchi, E.; Iwasaki, H.; Jones, M. D.; Langer, C.; Lee, I. Y.; Loelius, C.; Lunderberg, E.; Morse, C.; Rissanen, J.; Salathe, M.; Smalley, D.; Stroberg, S. R.; Weisshaar, D.; Whitmore, K.; Wiens, A.; Williams, S. J.; Wimmer, K.; Yamamato, T.

2017-07-01

The “Island of Inversion” at N~20 for the neon, sodium, and magnesium isotopes has long been an area of interest both experimentally and theoretically due to the subtle competition between 0p-0h and np-nh configurations leading to deformed shapes. However, the presence of rotational band structures, which are fingerprints of deformed shapes, have only recently been observed in this region. In this work, we report on a measurement of the low-lying level structure of 33Mg populated by a two-stage projectile fragmentation reaction and studied with GRETINA. The experimental level energies, ground state magnetic moment, intrinsic quadrupole moment, and γ-ray intensities show good agreement with the strong-coupling limit of a rotational model.

Experimental Study on the Measurement of Water Bottom Vibration Induced by Underwater Drilling Blasting

Directory of Open Access Journals (Sweden)

Gu Wenbin

2015-01-01

Full Text Available Due to the lack of proper instrumentations and the difficulties in underwater measurements, the studies about water bottom vibration induced by underwater drilling blasting are seldom reported. In order to investigate the propagation and attenuation laws of blasting induced water bottom vibration, a water bottom vibration monitor was developed with consideration of the difficulties in underwater measurements. By means of this equipment, the actual water bottom vibration induced by underwater drilling blasting was measured in a field experiment. It shows that the water bottom vibration monitor could collect vibration signals quite effectively in underwater environments. The followed signal analysis shows that the characteristics of water bottom vibration and land ground vibration induced by the same underwater drilling blasting are quite different due to the different geological environments. The amplitude and frequency band of water bottom vibration both exceed those of land ground vibration. Water bottom vibration is mainly in low-frequency band that induced by blasting impact directly acts on rock. Besides the low-frequency component, land vibration contains another higher frequency band component that induced by followed water hammer wave acts on bank slope.

FAULT DIAGNOSIS IN ROTATING MACHINE USING FULL SPECTRUM OF VIBRATION AND FUZZY LOGIC

Directory of Open Access Journals (Sweden)

ROGER R. DA SILVA

2017-11-01

Full Text Available Industries are always looking for more efficient maintenance systems to minimize machine downtime and productivity liabilities. Among several approaches, artificial intelligence techniques have been increasingly applied to machine diagnosis. Current paper forwards the development of a system for the diagnosis of mechanical faults in the rotating structures of machines, based on fuzzy logic, using rules foregrounded on the full spectrum of the machine´s complex vibration signal. The diagnostic system was developed in Matlab and it was applied to a rotor test rig where different faults were introduced. Results showed that the diagnostic system based on full spectra and fuzzy logic is capable of identifying with precision different types of faults, which have similar half spectrum. The methodology has a great potential to be implemented in predictive maintenance programs in industries and may be expanded to include the identification of other types of faults not covered in the case study under analysis.

The millimeter-wave spectrum of highly vibrationally excited SiO

International Nuclear Information System (INIS)

Mollaaghababa, R.; Gottlieb, C.A.; Vrtilek, J.M.; Thaddeus, P.

1991-01-01

The millimeter-wave rotational spectra of SiO in high vibrational states (v = 0-40) in its electronic ground state were measured between 228 and 347 GHz in a laboratory discharge through SiH4 and CO. On ascending the vibrational ladder, populations decline precipitously for the first few levels, with a vibrational temperature of about 1000 K; at v of roughly 3, however, they markedly flatten out, and from there to v of roughly 40 the temperature is of the order of 10,000 K. With the Dunham coefficients determined here, the rotational spectrum of highly vibrationally excited SiO can now be calculated into the far-infrared to accuracies required for radioastronomy. Possible astronomical sources of highly vibrationally excited SiO are certain stellar atmospheres, ultracompact H II regions, very young supernova ejecta, and dense interstellar shocks. 16 refs

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.

Influence of defects on the vibrations of rotating systems

International Nuclear Information System (INIS)

Lazarus, A.

2008-01-01

For high rotation speeds, the imperfections (cracks, anisotropy...) of rotating machinery of the energy sector lead to a specific vibratory behavior which can damage the machine. The simulation of rotating machinery are usually realized for systems without defect. The aim of this thesis is to understand the influence of defects and to propose an algorithm to predict the dynamical behavior. In a first part the author studies the simplified rotating oscillators to propose a numerical method in order to taking into account the dynamic of these systems. This method is then applied to real rotating machinery with the Cast3m software. The numerical results are validated with experiments. (A.L.B.)

Electron scattering from the octupole band in 238U

International Nuclear Information System (INIS)

Hirsch, A.; Creswell, C.; Bertozzi, W.; Heisenberg, J.; Hynes, M.V.; Kowalski, S.; Miska, H.; Norum, B.; Rad, F.N.; Sargent, C.P.; Sasanuma, T.; Turchinetz, W.

1978-01-01

A simple model for nuclear surface vibrations in permanently deformed nuclei does well in reproducing electron scattering cross sections of rotational levels built on a K/sup π/= 0 - intrinsic octupole vibration in 238 U

Shunted Piezoelectric Vibration Damping Analysis Including Centrifugal Loading Effects

Science.gov (United States)

Min, James B.; Duffy, Kirsten P.; Provenza, Andrew J.

2011-01-01

Excessive vibration of turbomachinery blades causes high cycle fatigue problems which require damping treatments to mitigate vibration levels. One method is the use of piezoelectric materials as passive or active dampers. Based on the technical challenges and requirements learned from previous turbomachinery rotor blades research, an effort has been made to investigate the effectiveness of a shunted piezoelectric for the turbomachinery rotor blades vibration control, specifically for a condition with centrifugal rotation. While ample research has been performed on the use of a piezoelectric material with electric circuits to attempt to control the structural vibration damping, very little study has been done regarding rotational effects. The present study attempts to fill this void. Specifically, the objectives of this study are: (a) to create and analyze finite element models for harmonic forced response vibration analysis coupled with shunted piezoelectric circuits for engine blade operational conditions, (b) to validate the experimental test approaches with numerical results and vice versa, and (c) to establish a numerical modeling capability for vibration control using shunted piezoelectric circuits under rotation. Study has focused on a resonant damping control using shunted piezoelectric patches on plate specimens. Tests and analyses were performed for both non-spinning and spinning conditions. The finite element (FE) shunted piezoelectric circuit damping simulations were performed using the ANSYS Multiphysics code for the resistive and inductive circuit piezoelectric simulations of both conditions. The FE results showed a good correlation with experimental test results. Tests and analyses of shunted piezoelectric damping control, demonstrating with plate specimens, show a great potential to reduce blade vibrations under centrifugal loading.

Piezoelectric pushers for active vibration control of rotating machinery

Science.gov (United States)

Palazzolo, A. B.; Lin, R. R.; Alexander, R. M.; Kascak, A. F.; Montague, J.

1989-01-01

The active control of rotordynamic vibrations and stability by magnetic bearings and electromagnetic shakers have been discussed extensively in the literature. These devices, though effective, are usually large in volume and add significant weight to the stator. The use of piezoelectric pushers may provide similar degrees of effectiveness in light, compact packages. Tests are currently being conducted with piezoelectric pusher-based active vibration control. Results from tests performed on NASA test rigs as preliminary verification of the related theory are presented.

Study on the annular leakage-flow-induced vibrations. 1st Report. Stability for translational and rotational single-degree-of-freedom systems; Kanjo sukimaryu reiki shindo ni kansuru kenkyu. 1. Heishin oyobi kaiten 1 jiyudokei no anteise

Energy Technology Data Exchange (ETDEWEB)

Li, D.W. [Hitachi, Ltd., Tokyo (Japan); Kaneko, S. [The University of Tokyo, Tokyo (Japan); Hayama, S. [Toyama Prefectural University, Toyama (Japan)

1999-07-25

This study reports the stability of annular leakage-flow-induced vibrations. The pressure distribution of fluid between a fixed outer cylinder and a vibrating inner cylinder was obtained in the case of a translationally and rotationally coupled motion of the inner cylinder. The unsteady fluid force acting on the inner cylinder in the case of translational and rotational single-degree-of-freedom vibrations was then expressed in terms proportional to the acceleration, velocity, and displacement. Then the critical flow rate (at which stability was lost) was determined for an annular leakage-flow-induced vibration. Finally, the stability was investigated theoretically. It is known that instability will occur in the case of a divergent passage, but the critical flow rate depends on the passage increment in a limited range: the eccentricity of the passage and the pressure loss factor at the inlet of the passage lower the stability. (author)

Shape transitions in neutron rich 110-112Ru nuclei and empirical relations

International Nuclear Information System (INIS)

Bihari, Chhail; Singh, Yuvraj; Gupta, K.K.; Varshney, A.K.; Singh, M.; Gupta, D.K.

2010-01-01

In the study of even even neutron rich Ru isotopes, the electromagnetic properties of the γ-vibrational bands are well described by a rigid triaxial rotor for lower spin state and by the rotation vibration collective model for the higher spin states. Thus interpretation in further suggested by the observation of nearly identical moment of inertia, the rotational frequency below the first band crossing, between the ground state and the γ-structural bands for both 110 Ru and 112 Ru which conclude a weak pairing, a more likely suitable explanation of observations. In the present work, the soft rotor energy formula is undertaken suggested by Brentano et al. for yrast band, may be employed to calculate the perturbed energies of the anomalous rotational band (γ-band) generated by rotation of the rigid asymmetric atomic nucleus and the two parameter formula (TPF) of Gupta et al.

Statistical Signal Processing by Using the Higher-Order Correlation between Sound and Vibration and Its Application to Fault Detection of Rotational Machine

Directory of Open Access Journals (Sweden)

Hisako Masuike

2008-01-01

Full Text Available In this study, a stochastic diagnosis method based on the changing information of not only a linear correlation but also a higher-order nonlinear correlation is proposed in a form suitable for online signal processing in time domain by using a personal computer, especially in order to find minutely the mutual relationship between sound and vibration emitted from rotational machines. More specifically, a conditional probability hierarchically reflecting various types of correlation information is theoretically derived by introducing an expression on the multidimensional probability distribution in orthogonal expansion series form. The effectiveness of the proposed theory is experimentally confirmed by applying it to the observed data emitted from a rotational machine driven by an electric motor.

Rotating machinery surveillance system reduces plant downtime and radiation exposure

International Nuclear Information System (INIS)

Bohanick, J.S.; Robinson, J.C.; Allen, J.W.

1988-01-01

A rotating machinery surveillance system (RMSS) was permanently installed at Grand Gulf nuclear station (GGNS) as part of a program sponsored by the US Department of Energy whose goal was to reduce radiation exposure to power plant personnel resulting from the inspection, maintenance, and repair of rotating machinery. The RMSS was installed at GGNS in 1983 to continuously monitor 173 analog vibration signals from proximity probes mounted on 26 machine trains and ∼450 process data points via a computer data link. Vibration frequency spectra, i.e., the vibration amplitude versus frequency of vibration, and various characterizations of these spectra are the fundamental data collected by the RMSS for performing machinery diagnostics. The RMSS collects vibration frequency spectra on a daily basis for all the monitored rotating equipment and automatically stores the collected spectra for review by the vibration engineer. Vibration spectra automatically stored by the RMSS fall into categories that include the last normal, alarm, minimum and maximum, past three-day data set, baseline, current, and user-saved spectra. During first and second fuel-cycle operation at GGNS, several significant vibration problems were detected by the RMSS. Two of these are presented in this paper: recirculation pumps and turbine-generator bearing degradation. The total reduction in personnel radiation exposure at GGNS from 1985 to 1987 due to the presence of the RMSS was estimated to be in the range from 49 to 54 person-rem

Integrated predictive maintenance program vibration and lube oil analysis: Part I - history and the vibration program

Energy Technology Data Exchange (ETDEWEB)

Maxwell, H.

1996-12-01

This paper is the first of two papers which describe the Predictive Maintenance Program for rotating machines at the Palo Verde Nuclear Generating Station. The organization has recently been restructured and significant benefits have been realized by the interaction, or {open_quotes}synergy{close_quotes} between the Vibration Program and the Lube Oil Analysis Program. This paper starts with the oldest part of the program - the Vibration Program and discusses the evolution of the program to its current state. The {open_quotes}Vibration{close_quotes} view of the combined program is then presented.

Spectra and relaxation dynamics of the pseudohalide (PS) vibrational bands for Ru(bpy){sub 2}(PS){sub 2} complexes, PS = CN, NCS and N{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Compton, Ryan; Gerardi, Helen K. [Chemistry Division, Naval Research Laboratory, Washington, DC 20375 (United States); Weidinger, Daniel [SRA International, 4300 Fair Lakes Court, Fairfax, VA 22033 (United States); Brown, Douglas J. [Chemistry Department, US Naval Academy, Annapolis, MD 21402 (United States); Dressick, Walter J. [Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375 (United States); Heilweil, Edwin J. [Radiation and Biomolecular Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Owrutsky, Jeffrey C., E-mail: Jeff.Owrutsky@nrl.navy.mil [Chemistry Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2013-08-30

Highlights: ► Static and transient infrared spectroscopy of pseudohalide bipyridine ruthenium complexes. ► Vibrational energy relaxes faster for the azide than the thiocyanate and cyanide analogs. ► Intramolecular vibrational relaxation is prevalent in cis-Ru(bpy){sub 2}(N{sub 3}){sub 2}. - Abstract: Static and transient infrared spectroscopy were used to investigate cis-Ru(bpy){sub 2}(N{sub 3}){sub 2} (bpy = 2,2′-bipyridine), cis-Ru(bpy){sub 2}(NCS){sub 2}, and cis-Ru(bpy){sub 2}(CN){sub 2} in solution. The NC stretching IR band for cis-Ru(bpy){sub 2}(NCS){sub 2} appears at higher frequency (∼2106 cm{sup −1} in DMSO) than for the free NCS{sup −} anion while the IR bands for the azide and cyanide complexes are closer to those of the respective free anions. The vibrational energy relaxation (VER) lifetime for the azide complex is found to be much shorter (∼5 ps) than for either the NCS or CN species (both ∼70 ps in DMSO) and the lifetimes resemble those for each corresponding free anion in solution. However, for cis-Ru(bpy){sub 2}(N{sub 3}){sub 2}, it is determined that the transition frequency depends more on the solvent than the VER lifetime implying that intramolecular vibrational relaxation is predominant over solvent energy-extracting interactions. These results are compared to the behavior of other related metal complexes in solution.

Vibrational Investigations of Silver-Doped Hydroxyapatite with Antibacterial Properties

OpenAIRE

Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Le Coustumer, Phillippe; Predoi, Daniela

2013-01-01

Silver-doped hydroxyapatite (Ag:HAp) was obtained by coprecipitation method. Transmission electron microscopy (TEM), infrared, and Raman analysis confirmed the development of Ag:HAp with good crystal structure. Transmission electron microscopy analysis showed an uniform ellipsoidal morphology with particles from 5 nm to 15 nm. The main vibrational bands characteristic to HAp were identified. The bands assigned to phosphate vibrational group were highlighted in infrared and Raman spectra. The...

The method of executing the vibration tendency management of the intermittent driving equipment in the nuclear plant

International Nuclear Information System (INIS)

Yonekawa, Yutaka; Fukunaga, Tatsuya

2008-01-01

The main rotary machine is often an intermittent driving machine in the nuclear plant. On the other hand, it was a problem for the vibration method to detect the vibration when rotating, and very to achieve the vibration tendency management for the equipment that did not rotate though it positively worked on the introduction of the equipment diagnosis technology by the vibration method of the rotation equipment in the nuclear plant. This time, because the tendency management system of the intermittent driving equipment is developed, and the tendency management was achieved, it introduces the outline and an actual case. (author)

Strongly coupled rotational band in ${}^{33}\mathrm{Mg}$

Energy Technology Data Exchange (ETDEWEB)

Richard, A. L. [Ohio Univ., Athens, OH (United States). Inst. for Nuclear and Particle Physics; Crawford, H. L. [Ohio Univ., Athens, OH (United States). Inst. for Nuclear and Particle Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Fallon, P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Macchiavelli, A. O. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Bader, V. M. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Bazin, D. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Bowry, M. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Campbell, C. M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Carpenter, M. P. [Argonne National Lab. (ANL), Argonne, IL (United States). Physics Div.; Clark, R. M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Cromaz, M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Gade, A. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Ideguchi, E. [Osaka Univ. (Japan). RCNP; Iwasaki, H. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Jones, M. D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Langer, C. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Lee, I. Y. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Loelius, C. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Lunderberg, E. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Morse, C. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Rissanen, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Salathe, M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Smalley, D. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Stroberg, S. R. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Weisshaar, D. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Whitmore, K. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Wiens, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Div.; Williams, S. J. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab; Wimmer, K. [Univ. of Tokyo (Japan). Dept. of Physics; Yamamato, T. [Osaka Univ. (Japan). RCNP

2017-07-01

The “island of inversion” at N≈20 for the neon, sodium, and magnesium isotopes has long been an area of interest both experimentally and theoretically due to the subtle competition between 0p-0h and np-nh configurations leading to deformed shapes. However, the presence of rotational band structures, which are fingerprints of deformed shapes, have only recently been observed in this region. In this work, we report on a measurement of the low-lying level structure of Mg33 populated by a two-stage projectile fragmentation reaction and studied with the Gamma Ray Energy Tracking In-Beam Nuclear Array (GRETINA). The experimental level energies, ground-state magnetic moment, intrinsic quadrupole moment, and γ-ray intensities show good agreement with the strong-coupling limit of a rotational model.

Structure of vibrational and rotational nuclei

International Nuclear Information System (INIS)

Otsuka, Takaharu

1980-01-01

The nuclear collective motion is discussed in terms of the Interacting Boson Model (IBM). Results of phenomenological studies by the IBM are presented, and the relation between the IBM and the geometrical models such as the vibration model, the rotor model, etc., is pointed out. A microscopic picture for the IBM is shown, in which bosons are introduced as a tool to describe the motion of nucleon pairs. It is emphasized that the IBM can give a unified understanding of the nuclear collective motion. (author)

Vibrational polarizabilities of hydrogen-bonded water

International Nuclear Information System (INIS)

Torii, Hajime

2013-01-01

Highlights: ► Vibrational polarizabilities of hydrogen-bonded water are analyzed theoretically. ► Total vibrational polarizability is (at least) comparable to the electronic one. ► Molecular translations contribute to the vibrational polarizability below 300 cm −1 . ► Intermolecular charge fluxes along H bonds are induced by molecular translations. ► The results are discussed in relation to the observed dielectric properties. - Abstract: The vibrational polarizabilities and the related molecular properties of hydrogen-bonded water are analyzed theoretically, taking the case of (water) 30 clusters as an example case. It is shown that some off-diagonal dipole derivatives are large for the translations of incompletely hydrogen-bonded molecules, and this is reasonably explained by the scheme of intermolecular charge fluxes induced along hydrogen bonds. In total, because of these intermolecular charge fluxes, molecular translations give rise to the vibrational polarizability of 2.8–3.3 a 0 3 per molecule, which is as large as about 40% of the electronic polarizability, mainly in the frequency region below 300 cm −1 . Adding the contributions of the molecular rotations (librations) and the translation–rotation cross term, the total polarizability (electronic + vibrational) at ∼100 cm −1 is slightly larger than the double of that at >4000 cm −1 . The relation of these results to some observed time- and frequency-dependent dielectric properties of liquid water is briefly discussed

Infrared Spectra of the 10-μm Bands of 1,2-Difluoroethane and 1,1,2-Trifluoroethane: Vibrationally Mediated Torsional Tunneling in 1,1,2-Trifluoroethane

Science.gov (United States)

Stone, Stephen C.; Miller, C. Cameron; Philips, Laura A.; Andrews, A. M.; Fraser, G. T.; Pate, B. H.; Xu, Li-Hong

1995-12-01

The 3-MHz-resolution infrared spectra of the 10-μm bands of thegaucheconformer of 1,2-difluoroethane (HFC152) and theC1-symmetry conformer of 1,1,2-trifluoroethane (HFC143) have been measured using a molecular-beam electric-resonance optothermal spectrometer with a tunable microwave-sideband CO2laser source. For 1,2-difluoroethane, two bands have been studied, the ν17B-symmetry C-F stretch at 1077.3 cm-1and the ν13B-symmetry CH2rock at 896.6 cm-1. Both bands are well fit to a asymmetric-rotor Hamiltonian to better than 0.5 MHz. The ν13band is effectively unperturbed, while the ν17band is weakly perturbed, as shown by the large change in centrifugal distortion constants from the ground state values. Two bands have also been studied for 1,1,2-trifluoroethane, the ν11symmetric CF2stretch at 1077.2 cm-1and the ν13C-C stretch at 905.1 cm-1. One of the two bands, ν11, is unperturbed and fit to near the experimental precision. The ν13vibration, on the other hand, is weakly perturbed by an interaction with a nearby state. This perturbation leads to a doubling or splitting of the lines, due to a perturbation-induced lifting of the degeneracy of the symmetric and antisymmetric tunneling states associated with tunneling between the two equivalentC1forms. For theJ,Kastates studied, the splittings are as large as 37 MHz. Combining this observation with published low-resolution far-infrared measurements of torsional sequence-band and hot-band frequencies and calculations from an empirical torsional potential allows us to identify the perturbing state as ν17+ 6ν18. Here, ν17is the CF2twist and ν18is the torsion. The matrix element responsible for this interaction exchanges eight vibrational quanta!

Theoretical and Spectroscopic investigations of conformations, rotational barriers and scaled vibrations of 2,3-dimethyl hexane

Directory of Open Access Journals (Sweden)

Aziz Aboulmouhajir

2017-01-01

Full Text Available The 2,3-dimethyl hexane conformational isomerism has been investigated in detail, based on HF, Post-HF and DFT calculations at different basis set. The effect of size of basis, ZPE, thermal contributions, electronic correlation and optimization methods on the conformational stability was discussed. The rotational barriers from the most stable conformer to the lowest energy secondary conformers and their correspondent inversion barriers at both HF and MP2 methods using 6-31G* basis set have also been approached. A normal mode calculation of the most and less-stable conformers using a scaled ab initio force field in terms of non-redundant local symmetry coordinates have been made to elucidate the conformational dependence of the vibrational spectra.

Vibration Spectrum Analysis for Indicating Damage on Turbine and Steam Generator Amurang Unit 1

Directory of Open Access Journals (Sweden)

Beny Cahyono

2017-12-01

Full Text Available Maintenance on machines is a mandatory asset management activity to maintain asset reliability in order to reduce losses due to failure. 89% of defects have random failure mode, the proper maintenance method is predictive maintenance. Predictive maintenance object in this research is Steam Generator Amurang Unit 1, which is predictive maintenance is done through condition monitoring in the form of vibration analysis. The conducting vibration analysis on Amurang Unit 1 Steam Generator is because vibration analysis is very effective on rotating objects. Vibration analysis is predicting the damage based on the vibration spectrum, where the vibration spectrum is the result of separating time-based vibrations and simplifying them into vibrations based on their frequency domain. The transformation of time-domain-wave into frequency-domain-wave is using the application of FFT, namely AMS Machinery. The measurement of vibration value is done on turbine bearings and steam generator of Unit 1 Amurang using Turbine Supervisory Instrument and CSI 2600 instrument. The result of this research indicates that vibration spectrum from Unit 1 Amurang Power Plant indicating that there is rotating looseness, even though the vibration value does not require the Unit 1 Amurang Power Plant to stop operating (shut down. This rotating looseness, at some point, can produce some indications that similar with the unbalance. In order to avoid more severe vibrations, it is necessary to do inspection on the bearings in the Amurang Unit 1 Power Plant.

Report on achievements in fiscal 1998. Venture business growing type consortium - small business creating infrastructure (Research and development of ultrasonic vibration machining and electrochemical reaction compound high-efficiency and ultra precision damage-free machining); 1998 nendo chochoonpa shindo denki kagaku hanno fukugogata konoritsu choseimitsu damage free kakoho no kenkyu kaihatsu seika hokokusho. 2

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The present research and development is intended to establish the ultrasonic vibration machining process (ultrasonic vibration means vibration with frequency band exceeding 60 kHz), and ultrasonic vibration machining and electrochemical reaction compound machining process. The following research assignments were executed: (1) development of an ultrasonic vibration machining device and tools, (2) fundamental study on ultrasonic vibration grinding, (3) development of an ultrasonic vibration machining and electrochemical reaction compound damage-free grinding device and tools, and (4) development of ultrasonic vibration machining and electrochemical reaction compound damage-free grinding technology. The achievements in the current fiscal year may be summarized as follows: (1) an ultrasonic vibration rotating main-shaft unit and an electrically insulated tool holder were developed; (2) developments were made on a grinding process by using a micro-diameter grinding wheel supported by ultrasonic vibration, a micro field pick-up unit process using the same wheel, fabrication of micro tools by means of the ultrasonic vibration grinding, processing by using a drill with very small diameter based on the ultrasonic vibration grinding, and a technology to drill holes by means of ultrasonic vibration using a machine-made drill; (3) an ultrasonic vibration rotating main shaft unit with variable amplitude at 75 kHz was developed; and (4) an interface reaction compound grinding process supported by ultrasonic vibration was developed. (NEDO)

Spectroscopy of vibrationally hot molecules: Hydrogen cyanide and acetylene

International Nuclear Information System (INIS)

Jonas, D.M.

1992-01-01

An efficient formula for calculating nuclear spin statistical weights is presented. New experimental methods to distinguish electric and magnetic multipole transitions are proposed and used to prove that the formaldehyde A - X 0-0 transition is a magnetic dipole transition. HIgh resolution vacuum ultraviolet studies of the A → X fluorescence excitation spectrum of hydrogen cyanide (HCN) have: (i) determined that only the (0,1,0) vibrational level of the HCN A-state has a sufficiently long fluorescence lifetime to be suitable for Stimulated Emission Pumping (SEP) studies; and (ii) measured the electric dipole moment of the A-state. Several transitions in the hydrogen cyanide A → X SEP spectrum are shown to be due to the axis-switching mechanism. From a Franck-Condon plot of the intensities and a comparison between sums of predicted rotational constants and sums of observed rotational constants, all of the remaining transitions in the SEP spectrum can be securly assigned. Two weak resonances; a 2:3 CH:CN stretch Fermi resonance and a 6:2 bend:CN stretch resonance appear in the SEP spectrum. Excitation of the CH stretching vibration is predicted and shown to be entirely absent, apart from resonances, in the HCN SEP spectrum. A → X SEP spectra of acetylene (HCCH) near E VIB = 7,000 cm -1 display a wealth of strong and fully assignable anharmonic resonances and forbidden rotational transitions. It is proved that Darling-Dennison resonance between the cis and trans bending vibrations is the crucial first step in a series of anharmonic resonances which can transfer nearly all the vibrational energy out of the initial CC stretch/trans-bend excitation at high vibrational energy. Secondary steps in the vibrational energy flow are vibrational-l-resonance and the '2345' Fermi resonance. For short times, the vibrational energy redistribution obeys very restrictive rules

Strong thermal nonequilibrium in hypersonic CO and CH4 probed by CRDS.

Science.gov (United States)

Louviot, M; Suas-David, N; Boudon, V; Georges, R; Rey, M; Kassi, S

2015-06-07

A new experimental setup coupling a High Enthalpy Source (HES) reaching 2000 K to a cw-cavity ring-down spectrometer has been developed to investigate rotationally cold hot bands of polyatomic molecules in the [1.5, 1.7] μm region. The rotational and vibrational molecular degrees of freedom are strongly decoupled in the hypersonic expansion produced by the HES and probed by cavity ring-down spectroscopy. Carbon monoxide has been used as a first test molecule to validate the experimental approach. Its expansion in argon led to rotational and vibrational temperatures of 6.7 ± 0.8 K and 2006 ± 476 K, respectively. The tetradecad polyad of methane (1.67 μm) was investigated under similar conditions leading to rotational and vibrational temperatures of 13 ± 5 K and 750 ± 100 K, respectively. The rotationally cold structure of the spectra reveals many hot bands involving highly excited vibrational states of methane.

Automated Registration of Images from Multiple Bands of Resourcesat-2 Liss-4 camera

Science.gov (United States)

Radhadevi, P. V.; Solanki, S. S.; Jyothi, M. V.; Varadan, G.

2014-11-01

Continuous and automated co-registration and geo-tagging of images from multiple bands of Liss-4 camera is one of the interesting challenges of Resourcesat-2 data processing. Three arrays of the Liss-4 camera are physically separated in the focal plane in alongtrack direction. Thus, same line on the ground will be imaged by extreme bands with a time interval of as much as 2.1 seconds. During this time, the satellite would have covered a distance of about 14 km on the ground and the earth would have rotated through an angle of 30". A yaw steering is done to compensate the earth rotation effects, thus ensuring a first level registration between the bands. But this will not do a perfect co-registration because of the attitude fluctuations, satellite movement, terrain topography, PSM steering and small variations in the angular placement of the CCD lines (from the pre-launch values) in the focal plane. This paper describes an algorithm based on the viewing geometry of the satellite to do an automatic band to band registration of Liss-4 MX image of Resourcesat-2 in Level 1A. The algorithm is using the principles of photogrammetric collinearity equations. The model employs an orbit trajectory and attitude fitting with polynomials. Then, a direct geo-referencing with a global DEM with which every pixel in the middle band is mapped to a particular position on the surface of the earth with the given attitude. Attitude is estimated by interpolating measurement data obtained from star sensors and gyros, which are sampled at low frequency. When the sampling rate of attitude information is low compared to the frequency of jitter or micro-vibration, images processed by geometric correction suffer from distortion. Therefore, a set of conjugate points are identified between the bands to perform a relative attitude error estimation and correction which will ensure the internal accuracy and co-registration of bands. Accurate calculation of the exterior orientation parameters with

Theoretical study on rotational bands and shape coexistence of 183,185,187Tl in the particle-triaxial-rotor model

International Nuclear Information System (INIS)

Chen Guojie; Cao Hui; Liu Yuxin; Song Huichao

2006-01-01

By taking the particle-triaxial-rotor model with variable moment of inertia, we systematically investigate the energy spectra, deformations, and single-particle configurations of the nuclei 183,185,187 Tl. The calculated energy spectra agree quite well with experimental data. The obtained results indicate that the rotation-aligned bands observed in 183,185,187 Tl originate from one of the [530](1/2) - ,[532](3/2) - ,[660](1/2) + proton configurations coupled to a prolate deformed core. Furthermore, the negative parity bands built upon the (9/2) - isomeric states in 183,185,187 Tl are formed by a proton with the [505](9/2) - configuration coupled to a core with triaxial oblate deformation, and the positive parity band on the (13/2) + isomeric state in 187 Tl is generated by a proton with configuration [606](13/2) + coupled to a triaxial oblate core

Microscopic description of rotational spectra including band-mixing. 1. Formulation in a microscopic basis

International Nuclear Information System (INIS)

Brut, F.; Jang, S.

1982-05-01

Within the framework of the projection theory of collective motion, a microscopic description of the rotational energy with band-mixing is formulated using a method based on an inverse power perturbation expansion in a quantity related to the expectation value of the operator Jsub(y)sup(2). The reliability of the present formulation is discussed in relation to the difference between the individual wave functions obtained from the variational equations which are established before and after projection. In addition to the various familiar quantities which appear in the phenomenological energy formula, such as the moment of inertia parameter, the decoupling factor and the band-mixing matrix element for ΔK=1, other unfamiliar quantities having the factors with peculiar phases, (-1)sup(J+1)J(J+1), (-1)sup(J+3/2)(J-1/2)(J+1/2)(J+3/2), (-1)sup(J+1/2)(J+1/2)J(J+1), (-1)sup(J)J(J+1)(J-1)(J+2) and [J(J+1)] 2 are obtained. The band-mixing term for ΔK=2 is also new. All these quantities are expressed in terms of two-body interactions and expectation values of the operator Jsub(y)sup(m), where m is an integer, within the framework of particle-hole formalism. The difference between the moment of inertia of an even-even and a neighboring even-odd nucleus, as well as the effect of band-mixing on the moment of inertia are studied. All results are put into the forms so as to facilitate comparisons with the corresponding phenomenological terms and also for further application

Seismic isolation floor and vibration control equipment for nuclear power plant

International Nuclear Information System (INIS)

Niwa, H.; Fujimoto, S.; Aida, Y.; Miyano, H.

1996-01-01

We have developed a seismic isolation floor to improve protection against earthquakes for process computer systems, and a magnetic dynamic damper to reduce the mechanical vibrations of piping systems and pumps in nuclear power plants. Seismic excitation tests of the seismic isolation floor, on which process computer systems were installed, were performed using large earthquake simulators. The test results proved that the seismic isolation floor significantly reduced seismic forces. To control mechanical vibrations, a magnetic dynamic damper was designed using permanent magnets. This magnetic dynamic damper does not require mechanical springs, dampers and supports in the floors and walls of the building. Vibration tests using a rotating machine model confirmed that the magnetic dynamic damper effectively controlled vibrations in such a rotating machine model. (author)

OD bands in the IR spectra of a deuterated soda-lime-silica glass

Energy Technology Data Exchange (ETDEWEB)

Peuker, C.; Brzezinka, K.W.; Gaber, M.; Kohl, A.; Geissler, H. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

2001-07-01

IR spectra of a deuterated glass of the composition (in mol%) 16 Na{sub 2}O . 10 CaO . 74 SiO{sub 2} complete earlier spectroscopic studies on water-poor soda-lime-silica glasses. The approved IR spectroscopic method of the deuterium exchange allows a reliable assignment of the hydroxyl bands also in the case of glasses. By spectra comparison the assignment of the IR bands at 3500 and 2800 cm{sup -1} to hydroxyl groups with different hydrogen bonding is verified. The IR band at about 4500 cm{sup -1} is interpreted as both a combination of the stretching vibrations {nu}O-H and {nu}Si-OH and a combination of the stretching vibration {nu}O-H and the deformation vibration {delta}SiOH. The bands at 1763 and 1602 cm{sup -1} are attributed to combination vibrations of the glass network. (orig.)

Femtosecond time-resolved studies of coherent vibrational Raman scattering in large gas-phase molecules

International Nuclear Information System (INIS)

Hayden, C.C.; Chandler, D.W.

1995-01-01

Results are presented from femtosecond time-resolved coherent Raman experiments in which we excite and monitor vibrational coherence in gas-phase samples of benzene and 1,3,5-hexatriene. Different physical mechanisms for coherence decay are seen in these two molecules. In benzene, where the Raman polarizability is largely isotropic, the Q branch of the vibrational Raman spectrum is the primary feature excited. Molecules in different rotational states have different Q-branch transition frequencies due to vibration--rotation interaction. Thus, the macroscopic polarization that is observed in these experiments decays because it has many frequency components from molecules in different rotational states, and these frequency components go out of phase with each other. In 1,3,5-hexatriene, the Raman excitation produces molecules in a coherent superposition of rotational states, through (O, P, R, and S branch) transitions that are strong due to the large anisotropy of the Raman polarizability. The coherent superposition of rotational states corresponds to initially spatially oriented, vibrationally excited, molecules that are freely rotating. The rotation of molecules away from the initial orientation is primarily responsible for the coherence decay in this case. These experiments produce large (∼10% efficiency) Raman shifted signals with modest excitation pulse energies (10 μJ) demonstrating the feasibility of this approach for a variety of gas phase studies. copyright 1995 American Institute of Physics

Blade dynamic stress analysis of rotating bladed disks

Directory of Open Access Journals (Sweden)

Kellner J.

2007-10-01

Full Text Available The paper deals with mathematical modelling of steady forced bladed disk vibrations and with dynamic stress calculation of the blades. The blades are considered as 1D kontinuum elastic coupled with three-dimensional elastic disk centrally clamped into rotor rotating with constant angular speed. The steady forced vibrations are generated by the aerodynamic forces acting along the blade length. By using modal synthesis method the mathematical model of the rotating bladed disk is condensed to calculate steady vibrations. Dynamic stress analysis of the blades is based on calculation of the time dependent reduced stress in blade cross-sections by using Hubert-Misses-Hencky stress hypothesis. The presented method is applied to real turbomachinery rotor with blades connected on the top with shroud.

Fast Fourier transformation in vibration analysis of physically active systems

International Nuclear Information System (INIS)

Hafeez, T.; Amir, M.; Farooq, U.; Day, P.

2003-01-01

Vibration of all physical systems may be expressed as the summation of an infinite number of sine and cosine terms known as Fourier series. The basic vibration analysis tool used is the frequency 'spectrum' (a graph of vibration where the amplitude of vibration is plotted against frequency). When a particular rotating component begins to fail, its vibration tends to increase. Spectra graphs are powerful diagnostic tool for detecting components' degradation. Spectra obtained with accelerometers located at the various locations on the components and their analysis in practice from rotating machines enable early detecting of incipient failure. Consequence of unexpected failure can be catastrophic and costly. This study provides basis to relate defective component by its constituent frequencies and then to the known discrete frequency of its 'signature' or 'thumbprint' to predict and verify the sustained dynamic behavior of machine designs harmful effects of forced vibration. The spectra for gearbox of a vane with teeth damaged fault are presented here which signified the importance of FFT analysis as diagnostic tool. This may be helpful to predictive maintenance of the machinery. (author)

Unbalance influence on the rotating assembly dynamics of a hydro

Science.gov (United States)

Jurcu, M.; Pădureanu, I.; Campian, C. V.; Haţiegan, C.

2018-01-01

The dynamics of the rotating parts of a hydro is characterized by the dynamic interaction between the rotor, the stator and the working fluid in order to operate the hydro. The main factors influencing the dynamics of the rotating parts of a hydro are: rotor unbalance, unbalanced magnetic pull, shaft misalignment and hydraulic flow regime. Rotor unbalanced is one of the most common factors influencing the dynamic stability of the rotating parts of a hydro. The unbalanced is determined by: uneven distribution of rotating masses, displacement of parts in the rotor during rotation, inhomogeneity of rotor component materials, expansion of the rotor due to heating, and rising speed during the transient discharge of the load. The mechanical imbalance of a rotor can lead to important forces, responsible for the vibration of the machine, which ultimately leads to a shorter operating time. Even a low unbalance can lead, in the case of high speed machines, to major unbalance forces that cause significant damage to the equipment. The unbalance forces cause additional vibrations in the bearings as well as in the foundation plate. To avoid these vibrations, it is necessary in the first stage to balance the static rotor in the construction plant and then to a dynamic rotation balancing.

Vibration vector monitoring of rotating machinery: A predictive/preventative maintenance technique

International Nuclear Information System (INIS)

Humes, B.R.

1990-01-01

Monitoring of overall vibration amplitudes to indicate machinery faults is a standard practice in most industries. The appearance of shaft cracks in machines retrofitted for extended life have prompted development of higher levels of machinery monitoring. Part 1 of this paper discusses vibration vector monitoring for machinery malfunction prediction and failure prevention. Machinery faults which can be diagnosed by this type of monitoring, such as rotor rubs, loose parts, shaft cracks, ..., are presented along with their most common characteristics. The newest, most effective methods of permanent machinery monitoring are presented and critiqued. An extensive case history is presented in Part 2 in which a potentially disastrous machinery fault was predicted using vibration vector monitoring and analysis. The addition of vector monitoring to the normal, overall vibration monitoring proved more effective in diagnosing the machinery fault and predicting impending failure

Accurate spectroscopic characterization of oxirane: A valuable route to its identification in Titan's atmosphere and the assignment of unidentified infrared bands

Energy Technology Data Exchange (ETDEWEB)

Puzzarini, Cristina [Dipartimento di Chimica " Giacomo Ciamician," Università di Bologna, Via Selmi 2, I-40126 Bologna (Italy); Biczysko, Malgorzata; Bloino, Julien; Barone, Vincenzo, E-mail: cristina.puzzarini@unibo.it [Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)

2014-04-20

In an effort to provide an accurate spectroscopic characterization of oxirane, state-of-the-art computational methods and approaches have been employed to determine highly accurate fundamental vibrational frequencies and rotational parameters. Available experimental data were used to assess the reliability of our computations, and an accuracy on average of 10 cm{sup –1} for fundamental transitions as well as overtones and combination bands has been pointed out. Moving to rotational spectroscopy, relative discrepancies of 0.1%, 2%-3%, and 3%-4% were observed for rotational, quartic, and sextic centrifugal-distortion constants, respectively. We are therefore confident that the highly accurate spectroscopic data provided herein can be useful for identification of oxirane in Titan's atmosphere and the assignment of unidentified infrared bands. Since oxirane was already observed in the interstellar medium and some astronomical objects are characterized by very high D/H ratios, we also considered the accurate determination of the spectroscopic parameters for the mono-deuterated species, oxirane-d1. For the latter, an empirical scaling procedure allowed us to improve our computed data and to provide predictions for rotational transitions with a relative accuracy of about 0.02% (i.e., an uncertainty of about 40 MHz for a transition lying at 200 GHz).

Optimal design of a magneto-rheological brake absorber for torsional vibration control

International Nuclear Information System (INIS)

Nguyen, Q H; Choi, S B

2012-01-01

This research presents an optimal design of a magneto-rheological (MR) brake absorber for torsional vibration control of a rotating shaft. Firstly, the configuration of an MR brake absorber for torsional vibration control of a rotating shaft system is proposed. Then, the braking torque of the MR brake is derived based on the Bingham plastic model of the MR fluid. By assuming that the behaviour of the MR brake absorber is similar to that of a dry friction torsional damper, the optimal braking torque to control the torsional vibration is determined and validated by simulation. The optimal design problem of the MR brake absorber is then developed and a procedure to solve the optimal problem is proposed. Based on the proposed optimal design procedure, the optimal design of a specific rotating shaft system is performed. Vibration control performance of the shaft system employing the optimized MR brake absorber is then investigated through simulation and discussion on the results is given. (paper)

Optimal design of a magneto-rheological brake absorber for torsional vibration control

Science.gov (United States)

Nguyen, Q. H.; Choi, S. B.

2012-02-01

This research presents an optimal design of a magneto-rheological (MR) brake absorber for torsional vibration control of a rotating shaft. Firstly, the configuration of an MR brake absorber for torsional vibration control of a rotating shaft system is proposed. Then, the braking torque of the MR brake is derived based on the Bingham plastic model of the MR fluid. By assuming that the behaviour of the MR brake absorber is similar to that of a dry friction torsional damper, the optimal braking torque to control the torsional vibration is determined and validated by simulation. The optimal design problem of the MR brake absorber is then developed and a procedure to solve the optimal problem is proposed. Based on the proposed optimal design procedure, the optimal design of a specific rotating shaft system is performed. Vibration control performance of the shaft system employing the optimized MR brake absorber is then investigated through simulation and discussion on the results is given.

Mehanizam trenja i trošenja vodećeg prstena projektila / Friction and wear mechanism of the projectile rotating band

Directory of Open Access Journals (Sweden)

Zoran Ristić

2005-09-01

Full Text Available U radu je opisan mehanizam trenja i trošenja vodećeg prstena projektila usled zagrevanja i topljenja kontaktne površine projektila. Primenjen je model hidrodinamičkog klizanja vodećeg prstena i postavljena Rejnoldsova jednačina za "fluid" (otopljeni film. Pretpostavlja se da je temperatura fluida konstantna i jednaka temperaturi topljenja na kontaktnim površinama. Na osnovu ukupnog prelaza toplote sa filma koji je stvoren između topljive i netopljive površine (model Landan određeni su rezultati za debljinu filma, koeficijent trenja i trošenje materijala. U raduje određena veličina trošenja vodećeg prstena i uticaj nekih parametara na silu trenja i debljinu filma otopljenog materijala prstena. Dobijeni rezultati ilustrovani su na odabranom primeru. / Friction and wear model of rotating band, due to, heating and melting material between the contact surface of a bore and projectile is described in this paper. The hydrodynamic slider-bearing model of the metal rotating band is applied and the Reynold's equation for the "fluid" (melting film has been used in this work. The fluid temperature was assumed to be constant and equal to the melting temperature on the contact surface. Based on the total heat transfer from the film, which is made, between the melting on the non-melting surface (Landan model and certain results of the film thickness, the coefficient of melt friction and the material wear were achieve. The size wears of the projectile rotating band and influence of certain parameters on the friction force and the film thickness are given in this paper. The achieved results have been illustrated by chosen example.

Flow induced vibrations in gas tube assembly of centrifuge

International Nuclear Information System (INIS)

Alam, M.; Atta, M.A.; Mirza, J.A.; Khan, A.Q.

1986-01-01

A centrifuge essentially consists of a rotor rotating at very high speed. Gas tube assembly, located at the center of the rotor, is used to introduce feed gas into the rotor and remove product and waste streams from it. The gas tube assembly is thus a static component, the product and waste scoops of which are lying in the high pressure region of a fluid rotating at very high speed. This can cause flow induced vibrations in the gas tube assembly. Such vibrations affect not only the mechanical stability of the gas tube assembly but may also reduce the separative power of the centrifuge. In a cascade, if some of the centrifuges have gas tube vibration, then cascade performance will be affected. A theoretical analysis of the effect of waste tube vibrations on product and waste flow rates and pressures in the centrifuge is presented. A simple stage consisting of two centrifuges, in which one has tube vibration, is considered for this purpose. The results are compared with experiment. It is shown that waste tube vibration generates oscillations in waste and product flow rates that are observable outside the centrifuge. (author)

Odd - even staggering, a result of γ - band split

International Nuclear Information System (INIS)

Singh, M.; Gupta, D.K.; Singh, Yuvraj; Gupta, K.K.; Bihari, Chhail; Sharma, Aparna; Varshney, A.K.; Varshney, Mani

2011-01-01

The structure of low - lying K = 2+ gamma band in even - even nuclei represents quadrupole vibration breaking axial symmetry in unified collective model of Bohr-Mottelson. In the group theoretical approach of the Interacting boson model (IBM) the band structure can belong to one of the three limiting symmetries of U (6) algebra viz. U (5), SU (3) and O (6), corresponding to the anharmonic vibrator, deformed rotor and γ - unstable respectively

Structure-dependent vibrational dynamics of Mg(BH ₄ ) ₂ polymorphs probed with neutron vibrational spectroscopy and first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Dimitrievska, Mirjana; White, James L.; Zhou, Wei; Stavila, Vitalie; Klebanoff, Leonard E.; Udovic, Terrence J.

2016-01-01

The structure-dependent vibrational properties of different Mg(BH4)2 polymorphs (..alpha.., ..beta.., ..gamma.., and ..delta.. phases) were investigated with a combination of neutron vibrational spectroscopy (NVS) measurements and density functional theory (DFT) calculations, with emphasis placed on the effects of the local structure and orientation of the BH4- anions. DFT simulations closely match the neutron vibrational spectra. The main bands in the low-energy region (20-80 meV) are associated with the BH4- librational modes. The features in the intermediate energy region (80-120 meV) are attributed to overtones and combination bands arising from the lower-energy modes. The features in the high-energy region (120-200 meV) correspond to the BH4- symmetric and asymmetric bending vibrations, of which four peaks located at 140, 142, 160, and 172 meV are especially intense. There are noticeable intensity distribution variations in the vibrational bands for different polymorphs. This is explained by the differences in the spatial distribution of BH4- anions within various structures. An example of the possible identification of products after the hydrogenation of MgB2, using NVS measurements, is presented. These results provide fundamental insights of benefit to researchers currently studying these promising hydrogen-storage materials.

Very high rotational excitation of CO in a cooled electric discharge through carbon monoxide

Science.gov (United States)

Cossart-Magos, Claudina; Cossart, Daniel

2000-02-01

Infrared emission from 12CO and 13CO, excited in the cathode region of a discharge tube immersed in liquid nitrogen, was recorded by Fourier-transform spectrometry at a resolution of 0.005 cm-1. The Δv=1 sequence bands recorded in the 2500-1800 cm-1 spectral interval, indicate the existence of three different rotational populations; (i) molecules in the zero-ground level with Trot≈100 K (responsible for reabsorption of part of the 1-0 emission band); (ii) molecules with Trot≈275 K (maximum intensity for Jmax'≈6 in each band, Tvib≈3000 K for v'=2-4, Tvib≈8600 K for v'=5-13); (iii) molecules with v' limited to 6, for which R-rotational lines are observed for J' values between 50 and 120 (Jmax'≈90, non-Boltzmannian population distribution). The full-width at half-maximum (FWHM) of all the observed lines is less than 0.007 cm-1. A Doppler width of 0.005 cm-1 and translational temperature Ttr≈280 K can be deduced. Such high-J levels of the CO molecule had never been observed in the laboratory. In the absorption spectrum of the Sun photosphere, the same lines present FWHM values 5-8 times larger. The best available Dunham coefficients are checked to reproduce the high-J lines wave numbers to at least 0.001 cm-1. Dissociative recombination of the dimer (CO)2+ cation, which is likely to be formed in our experimental conditions, is discussed as a possible mechanism to produce CO fragments with very high rotational excitation, while keeping vibrational excitation limited to v'=6.

Real-time dual-band haptic music player for mobile devices.

Science.gov (United States)

Hwang, Inwook; Lee, Hyeseon; Choi, Seungmoon

2013-01-01

We introduce a novel dual-band haptic music player for real-time simultaneous vibrotactile playback with music in mobile devices. Our haptic music player features a new miniature dual-mode actuator that can produce vibrations consisting of two principal frequencies and a real-time vibration generation algorithm that can extract vibration commands from a music file for dual-band playback (bass and treble). The algorithm uses a "haptic equalizer" and provides plausible sound-to-touch modality conversion based on human perceptual data. In addition, we present a user study carried out to evaluate the subjective performance (precision, harmony, fun, and preference) of the haptic music player, in comparison with the current practice of bass-band-only vibrotactile playback via a single-frequency voice-coil actuator. The evaluation results indicated that the new dual-band playback outperforms the bass-only rendering, also providing several insights for further improvements. The developed system and experimental findings have implications for improving the multimedia experience with mobile devices.

Intruder bands in Z = 51 nuclei

International Nuclear Information System (INIS)

LaFosse, D.R.

1993-01-01

Recent investigations of h 11/2 proton intruder bands in odd 51 Sb nuclei are reported. In addition to experiments performed at SUNY Stony Brook and Chalk River, data from Early Implementation of GAMMASPHERE (analysis in progress) are presented. In particular, the nuclei 109 Sb and 111 Sb are discussed. Rotational bands based on the πh 11/2 orbital coupled to a 2p2h deformed state of the 50 Sn core have been observed. These bands have been observed to high spin, and in the case of 109 Sb to a rotational frequency of 1.4 MeV, the highest frequency observed in a heavy nucleus. The dynamic moments of inertia in these bands decrease slowly with frequency, suggesting a gradual band termination. The systematics of such bands in 109-119 Sb will be discussed

Lattice vibrations and barrier to hindered rotation in lithium tetradeuteroaluminate by 2H, 7Li and 27Al NMR

International Nuclear Information System (INIS)

Tarasov, V.P.; Kirakosyan, G.A.

1996-01-01

Temperature dependences of 2 H, 7 Li, 27 Al NMR line shape in LiAlD 4 lithium polycrystal tetradeuteroaluminate in the range of 103-420 K have been studied. The quadrupole bond constants and asymmetry parameters of electric field gradient tensor have been measured. The frequencies of lattice vibrations have been evaluated in the framework of the Buyer model. From temperature dependences of spin-lattice relaxation time and 2 H NMR line shape the activation energies of AlD 4 anion decelerated rotation, amounting to 74 and 62 k J/mol respectively, have been determined. 15 refs.; 5 figs.; 2 tabs

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.

Back-to-basics with a surgical rotation programme.

Science.gov (United States)

Hall, Catherine L

This article describes the development and implementation of a rotation programme for Band 5 nurses within the surgical directorate at Heart of England NHS Foundation Trust. The article highlights the challenges raised for nurses with health service modernization and develops the rationale for the need for a different way of thinking. At Heart of England NHS Foundation Trust, the authors evaluation has led to the development of the surgical rotation programme for Band 5 nurses. This rotation programme challenged basic clinical practice and traditional modes of staff placement. Indications, so far, are that quality of care for patients has improved and nurses satisfaction has increased as a result of the implementation of the Band 5 surgical rotation programme.

Measurements of linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene in the ν4+ν5 combination band using a cw quantum cascade laser

KAUST Repository

Sajid, Muhammad Bilal

2014-11-01

Linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene have been measured at 296K in the P branch of the ν4+ν5 combination band for 25 rotational transitions. The effect of gas temperature is studied over 296-683K for five transitions to allow the determination of the temperature dependent exponent n for N2- and Ar-broadening coefficients. These measurements were performed using a continuous-wave quantum cascade laser (cw-QCL) operating over 1253-1310cm-1. Spectroscopic parameters were obtained by fitting absorption spectra using Voigt, Galatry and Rautian profiles. Linestrength and broadening results are compared with previous studies available in literature for the ν4+ν5 combination band and other vibrational bands of acetylene. © 2014 Elsevier Ltd.

Tube-AVB gap measurements using an eddy current rotating probe

International Nuclear Information System (INIS)

Badson, F.; Chiron, D.; Trumpff, B.

1988-01-01

The wears of tubes due to flow induced vibrations have been observed after a few years of operating PWR steam generators (SG). The vibration and wear are intimately related to the gap between tubes and anti-vibration bars (AVB's) located in the bundle. The authors report the development of an eddy current (EC) method for the measurement of this gap. The method is based on using an EC probe rotating in the tube. Since for each measurement zone the tube is interacting with two AVB's the use of a rotating EC probe is necessary to perform separate and accurate measurements of each tube-AVB gap

Translational and rotational dynamic analysis of a superconducting levitation system

International Nuclear Information System (INIS)

Cansiz, A; Hull, J R; Gundogdu, Oe

2005-01-01

The rotational dynamics of a disc-shaped permanent magnet rotor levitated over a high temperature superconductor was studied experimentally and theoretically. The interaction between the rotor magnet and the superconductor was modelled by assuming the magnet to be a magnetic dipole and the superconductor a diamagnet. In the magnetomechanical analysis of the superconductor part, the frozen image concept was combined with the diamagnetic image, and the damping in the system was neglected. The interaction potential of the system is the combination of magnetic and gravitational potentials. From the dynamical analysis the equations of motion of the permanent magnet were stated as a function of lateral, vertical, tilt, precision and rotating angles. The vibration behaviour and correlation of the vibration of one direction with that of another were determined with a numerical calculation based on the Runge-Kutta method. The various vibrational frequencies identified were vertical, radial, tilt, precession and rotation. The tests performed for experimental verifications were translational and rotational. The permanent magnet was 'spun up' under vacuum conditions to analyse the dynamics of the free 'spin down' behaviour of the permanent magnet

ExoMol line lists - IV. The rotation-vibration spectrum of methane up to 1500 K

Science.gov (United States)

Yurchenko, Sergei N.; Tennyson, Jonathan

2014-05-01

A new hot line list is calculated for 12CH4 in its ground electronic state. This line list, called 10to10, contains 9.8 billion transitions and should be complete for temperatures up to 1500 K. It covers the wavelengths longer than 1 μm and includes all transitions to upper states with energies below hc · 18 000 cm-1 and rotational excitation up to J = 39. The line list is computed using the eigenvalues and eigenfunctions of CH4 obtained by variational solution of the Schrödinger equation for the rotation-vibration motion of nuclei employing program TROVE and a new `spectroscopic' potential energy surface (PES) obtained by refining an ab initio PES (CCSD(T)-F12c/aug-cc-pVQZ) through least-squares fitting to the experimentally derived energies with J = 0-4 and a previously reported ab initio dipole moment surface (CCSD(T)-F12c/aug-cc-pVTZ). Detailed comparisons with other available sources of methane transitions including HITRAN, experimental compilations and other theoretical line lists show that these sources lack transitions both higher temperatures and near-infrared wavelengths. The 10to10 line list is suitable for modelling atmospheres of cool stars and exoplanets. It is available from the CDS data base as well as at www.exomol.com.

Infrared spectroscopy, vibrational predissociation dynamics and stability of the hydrogen trioxy (HOOO) radical and estimation of its abundance in the atmosphere

Science.gov (United States)

Derro, Erika L.

The hydrogen trioxy (HOOO) radical has been implicated as an important intermediate in key processes in the atmosphere. In the present studies, HOOO is produced by the combination of O2 and photolytically generated OH radicals in the collisional region of a pulsed supersonic expansion. Rotationally cooled HOOO is probed in the effectively collision-free region of the expansion using infrared action spectroscopy, an infrared-pump, ultraviolet-probe technique, in which HOOO is vibrationally excited and the nascent OH products of vibrational predissociation are probed via laser-induced fluorescence. High resolution infrared spectra of HOOO and DOOO were observed in the fundamental and overtone OH/D stretching regions (nui and 2nu 1), which comprise a rotationally structured band attributed to the trans conformer, and an unstructured component assigned to the cis conformer. Infrared spectra of HOOO and DOOO combination bands composed of the OH stretch and a low frequency mode (nu1 + nun) were also observed. This allowed identification of vibrational frequencies for five of the six modes for trans-H/DOOO and four of the six modes for cis-HOOO and DOOO. Identification of low frequency modes provides critical information on the vibrational dynamics and thermochemical properties of the HOOO radical, and furthermore, provides a potential means for detecting HOOO in situ in the atmosphere. In addition, the nascent OH X2pi products following vibrational predissociation of HOOO have been investigated. The product state distributions reveal a distinct preference for population of pi(A ') Λ-doublets in OH that is indicative of a planar dissociation of trans-HOOO in which the symmetry of the bonding orbital is maintained. The highest observed OH quantum state allows determination of the stability of HOOO relative to the OH + O 2 asymptote using a conservation of energy approach. In conjunction with a similar investigation of DOOO, the binding energy is determined to be ≤ 5

Vibrational transition moments of CH4 from first principles

Science.gov (United States)

Yurchenko, Sergei N.; Tennyson, Jonathan; Barber, Robert J.; Thiel, Walter

2013-09-01

New nine-dimensional (9D), ab initio electric dipole moment surfaces (DMSs) of methane in its ground electronic state are presented. The DMSs are computed using an explicitly correlated coupled cluster CCSD(T)-F12 method in conjunction with an F12-optimized correlation consistent basis set of the TZ-family. A symmetrized molecular bond representation is used to parameterise these 9D DMSs in terms of sixth-order polynomials. Vibrational transition moments as well as band intensities for a large number of IR-active vibrational bands of 12CH4 are computed by vibrationally averaging the ab initio dipole moment components. The vibrational wavefunctions required for these averages are computed variationally using the program TROVE and a new ‘spectroscopic’ 12CH4 potential energy surface. The new DMSs will be used to produce a hot line list for 12CH4.

Evidence for {open_quotes}magnetic rotation{close_quotes} in nuclei: New results on the M1-bands of {sup 198,199}Pb

Energy Technology Data Exchange (ETDEWEB)

Clark, R.M. [Lawrence Berkeley National Lab., CA (United States)

1996-12-31

Lifetimes of states in four of the M1-bands in {sup 198,199}Pb have been determined through a Doppler Shift Attenuation Method measurement performed using the Gammasphere array. The deduced B(M1) values, which are a sensitive probe of the underlying mechanism for generating these sequences, show remarkable agreement with Tilted Axis Cranking (TAC) calculations. Evidence is also presented for the possible termination of the bands. The results represent clear evidence for a new concept in nuclear excitations: {open_quote}magnetic rotation{close_quote}.

Vibration condition monitoring of planetary gearbox under varying external load

Energy Technology Data Exchange (ETDEWEB)

Bartelmus, W.; Zimroz, R. [Wroclaw University of Technology, Wroclaw (Poland)

2009-01-15

The paper shows that for condition monitoring of planetary gearboxes it is important to identify the external varying load condition. In the paper, systematic consideration has been taken of the influence of many factors on the vibration signals generated by a system in which a planetary gearbox is included. These considerations give the basis for vibration signal interpretation, development of the means of condition monitoring, and for the scenario of the degradation of the planetary gearbox. Real measured vibration signals obtained in the industrial environment are processed. The signals are recorded during normal operation of the diagnosed objects, namely planetary gearboxes, which are a part of the driving system used in a bucket wheel excavator, used in lignite mines. It has been found that the most important factor of the proper planetary gearbox condition is connected with perturbation of arm rotation, where an arm rotation gives rise to a specific vibration signal whose properties are depicted by a short-time Fourier transform (STFT) and Wigner-Ville distribution presented as a time-frequency map. The paper gives evidence that there are two dominant low-frequency causes that influence vibration signal modulation, i.e. the varying load, which comes from the nature of the bucket wheel digging process, and the arm/carrier rotation. These two causes determine the condition of the planetary gearboxes considered.

Vibrations of bioionic liquids by ab initio molecular dynamics and vibrational spectroscopy.

Science.gov (United States)

Tanzi, Luana; Benassi, Paola; Nardone, Michele; Ramondo, Fabio

2014-12-26

Density functional theory and vibrational spectroscopy are used to investigate a class of bioionic liquids consisting of a choline cation and carboxylate anions. Through quantum mechanical studies of motionless ion pairs and molecular dynamics of small portions of the liquid, we have characterized important structural features of the ionic liquid. Hydrogen bonding produces stable ion pairs in the liquid and induces vibrational features of the carboxylate groups comparable with experimental results. Infrared and Raman spectra of liquids have been measured, and main bands have been assigned on the basis of theoretical spectra.

Bound state potential energy surface construction: ab initio zero-point energies and vibrationally averaged rotational constants.

Science.gov (United States)

Bettens, Ryan P A

2003-01-15

Collins' method of interpolating a potential energy surface (PES) from quantum chemical calculations for reactive systems (Jordan, M. J. T.; Thompson, K. C.; Collins, M. A. J. Chem. Phys. 1995, 102, 5647. Thompson, K. C.; Jordan, M. J. T.; Collins, M. A. J. Chem. Phys. 1998, 108, 8302. Bettens, R. P. A.; Collins, M. A. J. Chem. Phys. 1999, 111, 816) has been applied to a bound state problem. The interpolation method has been combined for the first time with quantum diffusion Monte Carlo calculations to obtain an accurate ground state zero-point energy, the vibrationally average rotational constants, and the vibrationally averaged internal coordinates. In particular, the system studied was fluoromethane using a composite method approximating the QCISD(T)/6-311++G(2df,2p) level of theory. The approach adopted in this work (a) is fully automated, (b) is fully ab initio, (c) includes all nine nuclear degrees of freedom, (d) requires no assumption of the functional form of the PES, (e) possesses the full symmetry of the system, (f) does not involve fitting any parameters of any kind, and (g) is generally applicable to any system amenable to quantum chemical calculations and Collins' interpolation method. The calculated zero-point energy agrees to within 0.2% of its current best estimate. A0 and B0 are within 0.9 and 0.3%, respectively, of experiment.

SMAP Faraday Rotation

Science.gov (United States)

Le Vine, David

2016-01-01

Faraday rotation is a change in the polarization as signal propagates through the ionosphere. At L-band it is necessary to correct for this change and measurements are made on the spacecraft of the rotation angle. These figures show that there is good agreement between the SMAP measurements (blue) and predictions based on models (red).

Aircraft gas turbine engine vibration diagnostics

OpenAIRE

Stanislav Fábry; Marek Češkovič

2017-01-01

In the Czech and Slovak aviation are in service elderly aircrafts, usually produced in former Soviet Union. Their power units can be operated in more efficient way, in case of using additional diagnostic methods that allow evaluating their health. Vibration diagnostics is one of the methods indicating changes of rotational machine dynamics. Ground tests of aircraft gas turbine engines allow vibration recording and analysis. Results contribute to airworthiness evaluation and making corrections...

VIBRONIC PROGRESSIONS IN SEVERAL DIFFUSE INTERSTELLAR BANDS

International Nuclear Information System (INIS)

Duley, W. W.; Kuzmin, Stanislav

2010-01-01

A number of vibronic progressions based on low-energy vibrational modes of a large molecule have been found in the diffuse interstellar band (DIB) spectrum of HD 183143. Four active vibrational modes have been identified with energies at 5.18 cm -1 , 21.41 cm -1 , 31.55 cm -1 , and 34.02 cm -1 . The mode at 34.02 cm -1 was previously recognized by Herbig. Four bands are associated with this molecule, with origins at 6862.61 A, 6843.64 A, 6203.14 A, and 5545.11 A (14589.1 cm -1 , 14608.08 cm -1 , 16116.41 cm -1 , and 18028.9 cm -1 , respectively). The progressions are harmonic and combination bands are observed involving all modes. The appearance of harmonic, rather than anharmonic, terms in these vibronic progressions is consistent with torsional motion of pendant rings, suggesting that the carrier is a 'floppy' molecule. Some constraints on the type and size of the molecule producing these bands are discussed.

Origin of Spectral Band Patterns in the Cosmic Unidentified Infrared Emission

Science.gov (United States)

Álvaro Galué, Héctor; Díaz Leines, Grisell

2017-10-01

The cosmic unidentified infrared emission (UIE) band phenomenon is generally considered as indicative of free-flying polycyclic aromatic hydrocarbon molecules in space. However, a coherent explanation of emission spectral band patterns depending on astrophysical source is yet to be resolved under this attribution. Meanwhile astronomers have restored the alternative origin as due to amorphous carbon particles, but assigning spectral patterns to specific structural elements of particles is equally challenging. Here we report a physical principle in which inclusion of nonplanar structural defects in aromatic core molecular structures (π domains) induces spectral patterns typical of the phenomenon. We show that defects in model π domains modulate the electronic-vibration coupling that activates the delocalized π -electron contribution to aromatic vibrational modes. The modulation naturally disperses C =C stretch modes in band patterns that readily resemble the UIE bands in the elusive 6 - 9 μ m range. The electron-vibration interaction mechanics governing the defect-induced band patterns underscores the importance of π delocalization in the emergence of UIE bands. We discuss the global UIE band regularity of this range as compatible with an emission from the delocalized s p2 phase, as π domains, confined in disordered carbon mixed-phase aggregates.

Nature of the identical bands in atomic nuclei

International Nuclear Information System (INIS)

Szymanski, Z.

1995-01-01

Single-nucleon spectra in the fast rotating nuclei are shown to exhibit some special orbits that appear to be insensitive to nuclear rotation. It is suggested that the special orbits play an essential role in explaining the appearance and structure of the identical bands discovered in the superdeformed region. It is suggested that identical bands appear whenever the nucleonic orbit approaches the separatrix, i.e., a line dividing regions of different coupling schemes in a rotating mean field

RPC Calculations for K-forbidden Transitions in {sup 183}W, Evidence for Large Inertial Parameter Connected with High-lying Rotational Bands

Energy Technology Data Exchange (ETDEWEB)

Malmskog, S G [AB Atomenergi, Nykoeping (Sweden); Wahlborn, S [Div. of Theore tical Physics, Royal Inst. of Technology Stockholm (Sweden)

1967-09-15

Recent measurements have shown that the transitions deexciting the 453 keV 7/2{sup -} level in {sup 183}W to the K = 1/2{sup -} and 3/2{sup -} bands are strongly retarded. The data for B(M1) and B(E2) are analyzed in terms of the RPC model (rotation + particle motion + coupling). With the {delta}K = 1 (Coriolis) coupling, the K-forbidden M1-transitions proceed via admixtures of high-lying 5/2{sup -} bands. A reasonable and unambiguous fit to the data is obtained by varying the strength of the coupling. Allowing for various uncertainties and corrections, one finds that the inertial parameter (the inverse of the coupling constant, i. e. 2J(2{pi}){sup 2}/({Dirac_h}){sup 2} may have values between roughly 1 and 3 times the rigid rotator value of 2J(2{pi}){sup 2}/({Dirac_h}){sup 2}, thus being unexpectedly large. Calculations with the {delta}K=2 coupling were also performed and turn out not to give better agreement with experiment.

New results on the superdeformed {sup 196}Pb nucleus: The decay of the excited bands to the yrast band

Energy Technology Data Exchange (ETDEWEB)

Bouneau, S.; Azaiez, F.; Duprat, J. [IPN, Orsay (France)] [and others

1996-12-31

The study of the superdeformed (SD) {sup 196}Pb nucleus has been revisited using the EUROGAM phase 2 spectrometer. In addition to the known yrast and two lowest excited SD bands, a third excited SD band has been seen. All of the three excited bands were found to decay to the yrast SD band through, presumably, E1 transitions, allowing relative spin and excitation energy assignments. Comparisons with calculations using the random-phase approximation suggest that all three excited bands can be interpreted as octupole vibrational structures.

Neurocognitive responses to a single session of static squats with whole body vibration.

Science.gov (United States)

Amonette, William E; Boyle, Mandy; Psarakis, Maria B; Barker, Jennifer; Dupler, Terry L; Ott, Summer D

2015-01-01

The purpose of this study was to determine if the head accelerations using a common whole body vibration (WBV) exercise protocol acutely reduced neurocognition in healthy subjects. Second, we investigated differential responses to WBV plates with 2 different delivery mechanisms: vertical and rotational vibrations. Twelve healthy subjects (N = 12) volunteered and completed a baseline (BASE) neurocognitive assessment: the Immediate Postconcussion Assessment and Cognitive Test (ImPACT). Subjects then participated in 3 randomized exercise sessions separated by no more than 2 weeks. The exercise sessions consisted of five 2-minute sets of static hip-width stance squats, with the knees positioned at a 45° angle of flexion. The squats were performed with no vibration (control [CON]), with a vertically vibrating plate (vertical vibration [VV]), and with a rotational vibrating plate (rotational vibration [RV]) set to 30 Hz with 4 mm of peak-to-peak displacement. The ImPACT assessments were completed immediately after each exercise session and the composite score for 5 cognitive domains was analyzed: verbal memory, visual memory, visual motor speed, reaction time, and impulse control. Verbal memory scores were unaffected by exercise with or without vibration (p = 0.40). Likewise, visual memory was not different (p = 0.14) after CON, VV, or RV. Significant differences were detected for visual motor speed (p = 0.006); VV was elevated compared with BASE (p = 0.01). There were no significant differences (p = 0.26) in reaction time or impulse control (p = 0.16) after exercise with or without vibration. In healthy individuals, 10 minutes of 30 Hz, 4-mm peak-to-peak displacement vibration exposure with a 45° angle of knee flexion did not negatively affect neurocognition.

Fluctuation analysis of rotational spectra

International Nuclear Information System (INIS)

Doessing, T.; Bracco, A.; Broglia, R.A.; Matsuo, M.

1996-01-01

The compound state rotational degree of freedom is ''damped'' in the sense that the electric quadrupole decay of a single quantum state with angular momentum I exhibits a spectrum of final states all having spin I-2. In actual experiments, the cascade of γ-rays associated with each of the members of the ensemble of compound nuclei uses each of the ''discrete'' transitions many more times than the ''continuum'' transitions. Relatively large and small fluctuations in the recorded coincidence spectrum ensue, respectively. The analysis of the fluctuations will be shown to be instrumental to gain insight into the phenomenon of rotational damping. For this purpose, two- and higher-fold coincidence spectra emitted from rotating nuclei are analyzed with respect to the count fluctuations. The coincidences from consecutive γ-rays emitted from discrete rotational bands generate ridges in the E γ1 .E γ2 spectrum, and the fluctuation analysis of the ridges is based upon the ansatz of a random selection of transition energies from band to band. This ansatz is supported by a cranked mean-field calculation for the nucleus 168 Yb, as well as by analyzing resolved bands in 168 Yb and its neighbors. The fluctuation analysis of the central valley (E γ1 =E γ2 ) is based upon the ansatz of fluctuations in the intensity of the transitions of Porter-Thomas type superposed on a smooth spectrum of transition energies. This ansatz is again supported by a mixed-band calculation. The mathematical treatment of count fluctuations is formulated in general (orig.)

How do nuclei really vibrate or rotate

International Nuclear Information System (INIS)

Andresen, H.G.; Kunz, J.; Mosel, U.; Mueller, M.; Schuh, A.; Wust, U.

1983-01-01

By means of the adiabatic cranking model the properties of the current and velocity fields of nuclear quadrupole vibrations for even-even nuclei in the rare-earth region are investigated. BCS correlated wave functions based on the Nilsson single particle Hamiltonian have been used. The current fields are analyzed in terms of vector spherical harmonics. The realistic microscopic currents show a vortex structure not present in the classical irrotational flow. The microscopic origin of the vortex structure is investigated

Structures of the dehydrogenation products of methane activation by 5d transition metal cations revisited: Deuterium labeling and rotational contours

Science.gov (United States)

Owen, Cameron J.; Boles, Georgia C.; Chernyy, Valeriy; Bakker, Joost M.; Armentrout, P. B.

2018-01-01

A previous infrared multiple photon dissociation (IRMPD) action spectroscopy and density functional theory (DFT) study explored the structures of the [M,C,2H]+ products formed by dehydrogenation of methane by four, gas-phase 5d transition metal cations (M+ = Ta+, W+, Ir+, and Pt+). Complicating the analysis of these spectra for Ir and Pt was observation of an extra band in both spectra, not readily identified as a fundamental vibration. In an attempt to validate the assignment of these additional peaks, the present work examines the gas phase [M,C,2D]+ products of the same four metal ions formed by reaction with perdeuterated methane (CD4). As before, metal cations are formed in a laser ablation source and react with methane pulsed into a reaction channel downstream, and the resulting products are spectroscopically characterized through photofragmentation using the free-electron laser for intracavity experiments in the 350-1800 cm-1 range. Photofragmentation was monitored by the loss of D for [Ta,C,2D]+ and [W,C,2D]+ and of D2 in the case of [Pt,C,2D]+ and [Ir,C,2D]+. Comparison of the experimental spectra and DFT calculated spectra leads to structural assignments for all [M,C,2H/2D]+ systems that are consistent with previous identifications and allows a full description of the systematic spectroscopic shifts observed for deuterium labeling of these complexes, some of the smallest systems to be studied using IRMPD action spectroscopy. Further, full rotational contours are simulated for each vibrational band and explain several observations in the present spectra, such as doublet structures in several bands as well as the observed linewidths. The prominent extra bands in the [Pt,C,2D/2H]+ spectra appear to be most consistent with an overtone of the out-of-plane bending vibration of the metal carbene cation structure.

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...

Model reduction and analysis of a vibrating beam microgyroscope

KAUST Repository

Ghommem, Mehdi; Nayfeh, Ali Hasan; Choura, Slim A.

2012-01-01

The present work is concerned with the nonlinear dynamic analysis of a vibrating beam microgyroscope composed of a rotating cantilever beam with a tip mass at its end. The rigid mass is coupled to two orthogonal electrodes in the drive and sense directions, which are attached to the rotating base. The microbeam is driven by an AC voltage in the drive direction, which induces vibrations in the orthogonal sense direction due to rotation about the microbeam axis. The electrode placed in the sense direction is used to measure the induced motions and extract the underlying angular speed. A reduced-order model of the gyroscope is developed using the method of multiple scales and used to examine its dynamic behavior. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Model reduction and analysis of a vibrating beam microgyroscope

KAUST Repository

Ghommem, Mehdi

2012-05-08

The present work is concerned with the nonlinear dynamic analysis of a vibrating beam microgyroscope composed of a rotating cantilever beam with a tip mass at its end. The rigid mass is coupled to two orthogonal electrodes in the drive and sense directions, which are attached to the rotating base. The microbeam is driven by an AC voltage in the drive direction, which induces vibrations in the orthogonal sense direction due to rotation about the microbeam axis. The electrode placed in the sense direction is used to measure the induced motions and extract the underlying angular speed. A reduced-order model of the gyroscope is developed using the method of multiple scales and used to examine its dynamic behavior. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Optimum design of band-gap beam structures

DEFF Research Database (Denmark)

Olhoff, Niels; Niu, Bin; Cheng, Gengdong

2012-01-01

The design of band-gap structures receives increasing attention for many applications in mitigation of undesirable vibration and noise emission levels. A band-gap structure usually consists of a periodic distribution of elastic materials or segments, where the propagation of waves is impeded...... or significantly suppressed for a range of external excitation frequencies. Maximization of the band-gap is therefore an obvious objective for optimum design. This problem is sometimes formulated by optimizing a parameterized design model which assumes multiple periodicity in the design. However, it is shown...... in the present paper that such an a priori assumption is not necessary since, in general, just the maximization of the gap between two consecutive natural frequencies leads to significant design periodicity. The aim of this paper is to maximize frequency gaps by shape optimization of transversely vibrating...

[Study on plasma parameters in diffuse discharge with semispherical electrod by optical emission spectrum].

Science.gov (United States)

Dong, Li-Fang; Tong, Guo-Liang; Shen, Zhong-Kai; Liu, Liang; Ji, Ya-Fei; Zhao, Huan-Huan

2012-06-01

The diffuse discharge plasma in air was observed in a dielectric barrier discharge with two semispherical water electrodes. The variations of vibration temperature, rotation temperature, and average electron energy as the function of the applied voltage were studied by emission spectroscopy. The vibration temperature and the rotation temperature were calculated through the second positive band system (C3Pi(u)-->B3Pi(g)) of N2+ and the first negative band system (B2 Sigma(u+)-->Chi2Sigma(g+)) of N(2+) respectively. The average electron energy was studied by intensity ratio of 391.4 and 337.1 nm. It was found that the rotation temperature increases with the applied voltage increasing, while the vibration temperature and the electron energy decrease.

Effect of Spindle Parameters of Woodworking Band Saw on the AE Value of Crack Band Saw Blade in Compound Material Processing (1)

Science.gov (United States)

Gao, Jin-gui; Jiang, Zhao-fang; Luo, Lai-peng

2017-04-01

Taking the MJ3210A motion band saw as the research object, the AE value of the band saw blade vibration was obtained by analyzing the VIBSYS vibration signal acquisition and analysis software system in Beijing, and the change of the AE value of the band saw and the crack was found out. The experimental results show that in the MJ3210A sports car sawing machine, the band saw blade with width of 130 mm is used, and the AE value of the cracked band saw blade is well in the high band saw blade AE value. Under the best working condition of the band saw, the band saw blade AE If the value exceeds 104.7 dB (A) above, it means that the band saw blade has at least one crack length greater than 1.38 mm for the crack defect and the need to replace the band saw blade in time. Different species with saw blade of the AE value is different, white pine wood minimum, the largest oak wood; according to a variety of wood processing AE instrument value to determine the band saw blade crack to the situation; so as to fully rational use of band saw blade, The failure and the degree of development to find a new method.

Translational and rotational dynamic analysis of a superconducting levitation system

Energy Technology Data Exchange (ETDEWEB)

Cansiz, A [Electric-Electronic Engineering Department, Ataturk University, Erzurum (Turkey); Hull, J R [Energy Technology Division, Argonne National Laboratory, Argonne, IL (United States); Gundogdu, Oe [Mechanical Engineering Department, Ataturk University, Erzurum (Turkey)

2005-07-01

The rotational dynamics of a disc-shaped permanent magnet rotor levitated over a high temperature superconductor was studied experimentally and theoretically. The interaction between the rotor magnet and the superconductor was modelled by assuming the magnet to be a magnetic dipole and the superconductor a diamagnet. In the magnetomechanical analysis of the superconductor part, the frozen image concept was combined with the diamagnetic image, and the damping in the system was neglected. The interaction potential of the system is the combination of magnetic and gravitational potentials. From the dynamical analysis the equations of motion of the permanent magnet were stated as a function of lateral, vertical, tilt, precision and rotating angles. The vibration behaviour and correlation of the vibration of one direction with that of another were determined with a numerical calculation based on the Runge-Kutta method. The various vibrational frequencies identified were vertical, radial, tilt, precession and rotation. The tests performed for experimental verifications were translational and rotational. The permanent magnet was 'spun up' under vacuum conditions to analyse the dynamics of the free 'spin down' behaviour of the permanent magnet.

ExoMol line lists - VII. The rotation-vibration spectrum of phosphine up to 1500 K

Science.gov (United States)

Sousa-Silva, Clara; Al-Refaie, Ahmed F.; Tennyson, Jonathan; Yurchenko, Sergei N.

2015-01-01

A comprehensive hot line list is calculated for 31PH3 in its ground electronic state. This line list, called SAlTY, contains almost 16.8 billion transitions between 7.5 million energy levels and it is suitable for simulating spectra up to temperatures of 1500 K. It covers wavelengths longer than 1 μm and includes all transitions to upper states with energies below hc × 18 000 cm-1 and rotational excitation up to J = 46. The line list is computed by variational solution of the Schrödinger equation for the rotation-vibration motion employing the nuclear-motion program TROVE. A previously reported ab initio dipole moment surface is used as well as an updated `spectroscopic' potential energy surface, obtained by refining an existing ab initio surface through least-squares fitting to the experimentally derived energies. Detailed comparisons with other available sources of phosphine transitions confirms SAlTY's accuracy and illustrates the incompleteness of previous experimental and theoretical compilations for temperatures above 300 K. Atmospheric models are expected to severely underestimate the abundance of phosphine in disequilibrium environments, and it is predicted that phosphine will be detectable in the upper troposphere of many substellar objects. This list is suitable for modelling atmospheres of many astrophysical environments, namely carbon stars, Y dwarfs, T dwarfs, hot Jupiters and Solar system gas giant planets. It is available in full from the Strasbourg data centre, CDS, and at www.exomol.com.

Band mixing in /sup 160/Dy

Energy Technology Data Exchange (ETDEWEB)

Hasiza, M L; Singh, K; Sahota, H S [Punjabi Univ., Patiala (India). Dept. of Physics

1982-11-01

The intensities of the gamma transitions in /sup 160/Dy have been measured precisely by a 45 cc Ge(Li) detector. Unequal quadrupole moments for the ground and gamma vibrational bands have been proposed in order to remove the inconsistencies in the values of band mixing parameter Z sub(gamma) for this doubly even deformed nucleus of /sup 160/Dy.

Vibration analysis of a rotating functionally graded tapered microbeam based on the modified couple stress theory by DQEM

Science.gov (United States)

Ghadiri, Majid; Shafiei, Navvab; Alireza Mousavi, S.

2016-09-01

Due to having difficulty in solving governing nonlinear differential equations of a non-uniform microbeam, a few numbers of authors have studied such fields. In the present study, for the first time, the size-dependent vibration behavior of a rotating functionally graded (FG) tapered microbeam based on the modified couple stress theory is investigated using differential quadrature element method (DQEM). It is assumed that physical and mechanical properties of the FG microbeam are varying along the thickness that will be defined as a power law equation. The governing equations are determined using Hamilton's principle, and DQEM is presented to obtain the results for cantilever and propped cantilever boundary conditions. The accuracy and validity of the results are shown in several numerical examples. In order to display the influence of size on the first two natural frequencies and consequently changing of some important microbeam parameters such as material length scale, rate of cross section, angular velocity and gradient index of the FG material, several diagrams and tables are represented. The results of this article can be used in designing and optimizing elastic and rotary-type micro-electro-mechanical systems like micro-motors and micro-robots including rotating parts.

Rotationally resolved state-to-state photoionization and photoelectron study of titanium carbide and its cation (TiC/TiC⁺).

Science.gov (United States)

Luo, Zhihong; Huang, Huang; Chang, Yih-Chung; Zhang, Zheng; Yin, Qing-Zhu; Ng, C Y

2014-10-14

Titanium carbide and its cation (TiC/TiC(+)) have been investigated by the two-color visible (VIS)-ultraviolet (UV) resonance-enhanced photoionization and pulsed field ionization-photoelectron (PFI-PE) methods. Two visible excitation bands for neutral TiC are observed at 16,446 and 16,930 cm(-1). Based on rotational analyses, these bands are assigned as the respective TiC((3)Π1) ← TiC(X(3)Σ(+)) and TiC((3)Σ(+)) ← TiC(X(3)Σ(+)) transition bands. This assignment supports that the electronic configuration and term symmetry for the neutral TiC ground state are …7σ(2)8σ(1)9σ(1)3π(4) (X(3)Σ(+)). The rotational constant and the corresponding bond distance of TiC(X(3)Σ(+); v″ = 0) are determined to be B0″ = 0.6112(10) cm(-1) and r0″ = 1.695(2) Å, respectively. The rotational analyses of the VIS-UV-PFI-PE spectra for the TiC(+)(X; v(+) = 0 and 1) vibrational bands show that the electronic configuration and term symmetry for the ionic TiC(+) ground state are …7σ(2)8σ(1)3π(4) (X(2)Σ(+)) with the v(+) = 0 → 1 vibrational spacing of 870.0(8) cm(-1) and the rotational constants of B(e)(+) = 0.6322(28) cm(-1), and α(e)(+) = 0.0085(28) cm(-1). The latter rotational constants yield the equilibrium bond distance of r(e)(+) = 1.667(4) Å for TiC(+)(X(2)Σ(+)). The cleanly rotationally resolved VIS-UV-PFI-PE spectra have also provided a highly precise value of 53 200.2(8) cm(-1) [6.5960(1) eV] for the adiabatic ionization energy (IE) of TiC. This IE(TiC) value along with the known IE(Ti) has made possible the determination of the difference between the 0 K bond dissociation energy (D0) of TiC(+)(X(2)Σ(+)) and that of TiC(X(3)Σ(+)) to be D0(Ti(+)-C) - D0(Ti-C) = 0.2322(2) eV. Similar to previous experimental observations, the present state-to-state PFI-PE study of the photoionization transitions, TiC(+)(X(2)Σ(+); v(+) = 0 and 1, N(+)) ← TiC((3)Π1; v', J'), reveals a strong decreasing trend for the photoionization cross section as |ΔN(+)| = |N

Simulation of Vibrations in Real Time Plane Milling with Spindle Speed Correction

Directory of Open Access Journals (Sweden)

I. I. Ivanov

2017-01-01

Full Text Available In milling the hard-to-machine materials vibrations (chatter often arise from the high cutting forces if a technological system is insufficiently rigid.The main way to suppress these vibrations is to increase a stiffness of the mounting system of the tool and the work-piece to be machined. However, sometimes this method doesn’t lead to desirable result because of high values of intrinsic pliability of the tool and the work-piece. Currently, there are more complicated methods to ensure milling process quality. Among them there are three main groups:mathematical simulation of milling process dynamics and computation of processing parameters which provide high quality of machined surface, low level of vibrations and static deflections of a tool and a work-piece;introduction of the active vibration suppression devices into machine tool design; such devices include a vibration sensor, a feedback circuit, and an actuator which induces kinematic or force action on the oscillatory system;control of processing parameters, mainly of rotation frequency for minimizing the amplitudes of vibrations.The paper studies one of the 3rd group methods. There is a suggestion to process a signal of vibrational accelerations in real time and detect a chatter onset. If the chatter has been detected its frequency is to be identified, and the new value of rotation speed is set:where Ω – rotation frequency, rot/s; p – the tool eigenfrequency value identified during processing, Hz; z – mill tooth number; i – positive integer number; ε<1 – small positive parameter. In the current research it is assumed that ε = 0,2.The formula has been chosen because at the rotation frequency axis where tooth pass frequency is slightly less than the eigenfrequency divided by the integer value there are stable zones of dynamics in the milling process.The study shows a developed model of the plane milling dynamics. It includes a dynamic model of the tool, a model of cutting

High-spin rotational states in {sup 179}Os

Energy Technology Data Exchange (ETDEWEB)

Burde, J [Lawrence Berkeley Lab., CA (United States); [Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics; Deleplanque, M A; Diamond, R M; Macchiavelli, A O; Stephens, F S; Beausang, C W [Lawrence Berkeley Lab., CA (United States)

1992-08-01

The rotational bands of the osmium isotopes display very interesting properties that vary with the neutron number. On the one hand the yrast bands of {sup 182,184,186}Os display a sudden and rather strong gain in aligned angular momentum,, whereas the lighter osmium nuclei such as {sup 176,178,180}Os show a more gradual increase of alignment characteristic of strongly interacting bands. In addition, an unusual rotational band has been found in {sup 178}Os. It consists of seven regularly spaced transitions about 36 keV apart which correspond closely to the spacing of the superdeformed band in {sup 152}Dy after an A{sup 5/3} normalization. this band populates the yrast band directly, and the moment of inertia J{sup (1)} is found to be much smaller than J{sup (2)}. The most likely interpretation of this is a band with large deformation which is undergoing systematic changes in deformation, pairing and/or alignment. This latter finding in particular motivated us to carry out research on the higher spin states in {sup 179}Os. Dracoulis et al. have published their results on 5 rotational bands in {sup 179}Os. In the present work we found six new bands and extended appreciably the spin limits in the other five. (author). 5 refs., 3 figs.

High spin rotational bands in Zn

Indian Academy of Sciences (India)

We present here some preliminary results from our studies in the. ~ ¼ region in which we have observed an yrast band structure in Zn extending to spin (41/2 ). ... gaps implies that nuclei may exhibit different shapes at different excitation energies. .... uration, identifying previously unobserved states up to an excitation energy ...

Transport, dissociation and rotation of small self-interstitial atom clusters in tungsten

International Nuclear Information System (INIS)

Zhou, W.H.; Zhang, C.G.; Li, Y.G.; Zeng, Z.

2014-01-01

Numerical calculations have been performed to study the thermal motion of self-interstitial atom (SIA) clusters in tungsten (W). Molecular dynamics simulations show that SIA clusters exhibit a fast one-dimensional (1D) motion along the close packed 〈1 1 1〉 direction accompanied by a significant mass transport in this direction. A low frequency vibration mode is identified and considered to assist the motion of SIAs. The migration energy of SIA clusters are weakly dependent on their size in the average value of 0.019 eV, which is due to the strong interaction between SIAs revealed by calculating the potential energy curve of artificially moving the SIAs along 〈1 1 1〉 direction as well as nudged elastic band (NEB) method. The rotation process of SIA cluster is studied by activation–relaxation technique and the results show that SIA cluster presents complex rotation process. Our results on the motion SIA cluster may provide updated understanding on the performance decay of materials related to SIA defects

Rotational spectroscopy with an optical centrifuge.

Science.gov (United States)

Korobenko, Aleksey; Milner, Alexander A; Hepburn, John W; Milner, Valery

2014-03-07

We demonstrate a new spectroscopic method for studying electronic transitions in molecules with extremely broad range of angular momentum. We employ an optical centrifuge to create narrow rotational wave packets in the ground electronic state of (16)O2. Using the technique of resonance-enhanced multi-photon ionization, we record the spectrum of multiple ro-vibrational transitions between X(3)Σg(-) and C(3)Πg electronic manifolds of oxygen. Direct control of rotational excitation, extending to rotational quantum numbers as high as N ≳ 120, enables us to interpret the complex structure of rotational spectra of C(3)Πg beyond thermally accessible levels.

Diagnosis of subharmonic vibrations in rotating machinery

International Nuclear Information System (INIS)

Mott, J.E.

1977-01-01

The subject is discussed by reference to figures entitled as follows: an illustration of a shaft, mounted on rigid bearings, subjected to such a vibration; an illustration of fluid bearing whip; the displacement spectrum of an 1190 rpm (20Hz) pump with fluid bearing whip; an illustration of rubbing or dry frictional whip; the displacement spectrum measured by two sensors, located at the ten o'clock and two o'clock positions, on a horizontal pump with rub; and the vector resultant of these displacements, portraying the effect of two rubbing conditions. (UK)

Nightglow vibrational distributions in the A3Σu+ and A'3Δu states of O2 derived from astronomical sky spectra

Directory of Open Access Journals (Sweden)

T. G. Slanger

2004-09-01

Full Text Available Astronomical sky spectra from the Keck I telescope on Mauna Kea have been used to obtain vibrational distributions in the O2A3Σu+ and O2(A'3Δu states from rotationally-resolved Herzberg I and Chamberlain band emissions in the terrestrial nightglow. The A3Σu+ distribution is similar to that presented in earlier publications, with the exception that there is significant population in the previously undiscerned v=0 level. The vibrational distributions of the A'3Δu and A3Σu+ states are essentially the same when comparison is made in terms of the level energies. The intensity of Chamberlain band emission at the peak of the distribution is about one-fourth that of the Herzberg I emission, as previously shown, and may be related primarily to radiative efficiency. The peaks in both population distributions are about 0.25eV below the O(3P+O(3P dissociation limit. We compare these Herzberg state distributions with that of the O2(b1Σg+ state, concurring with others that the intense nightglow emission associated with b1Σg+(v=0 is a reflection of direct transfer from the Herzberg states. This process takes place following O2 collisions, with simultaneous production of very high a1Δg and b1Σg+ vibrational levels.

Excitation of blade vibration under rotation by synchronous electromagnet

Czech Academy of Sciences Publication Activity Database

Pešek, Luděk; Vaněk, František; Bula, Vítězslav; Cibulka, Jan

2011-01-01

Roč. 18, 3/4 (2011), s. 1-9 ISSN 1802-1484 R&D Projects: GA ČR GA101/09/1166 Institutional research plan: CEZ:AV0Z20760514 Keywords : blade * vibration * excitation * electromagnet Subject RIV: BI - Acoustics

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.