The High Level Vibration Test Program

International Nuclear Information System (INIS)

Hofmayer, C.H.; Curreri, J.R.; Park, Y.J.; Kato, W.Y.; Kawakami, S.

1989-01-01

As part of cooperative agreements between the United States and Japan, tests have been performed on the seismic vibration table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Test Center (NUPEC) in Japan. The objective of the test program was to use the NUPEC vibration table to drive large diameter nuclear power piping to substantial plastic strain with an earthquake excitation and to compare the results with state-of-the-art analysis of the problem. The test model was designed by modifying the 1/2.5 scale model of the PWR primary coolant loop. Elastic and inelastic seismic response behavior of the test model was measured in a number of test runs with an increasing excitation input level up to the limit of the vibration table. In the maximum input condition, large dynamic plastic strains were obtained in the piping. Crack initiation was detected following the second maximum excitation run. The test model was subjected to a maximum acceleration well beyond what nuclear power plants are designed to withstand. This paper describes the overall plan, input motion development, test procedure, test results and comparisons with pre-test analysis. 4 refs., 16 figs., 2 tabs

The High Level Vibration Test program

International Nuclear Information System (INIS)

Hofmayer, C.H.; Curreri, J.R.; Park, Y.J.; Kato, W.Y.; Kawakami, S.

1990-01-01

As part of cooperative agreements between the United States and Japan, tests have been performed on the seismic vibration table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Test Center (NUPEC) in Japan. The objective of the test program was to use the NUPEC vibration table to drive large diameter nuclear power piping to substantial plastic strain with an earthquake excitation and to compare the results with state-of-the-art analysis of the problem. The test model was designed by modifying the 1/2.5 scale model of the pressurized water reactor primary coolant loop. Elastic and inelastic seismic response behavior of the test model was measured in a number of test runs with an increasing excitation input level up to the limit of the vibration table. In the maximum input condition, large dynamic plastic strains were obtained in the piping. Crack initiation was detected following the second maximum excitation run. The test model was subjected to a maximum acceleration well beyond what nuclear power plants are designed to withstand. This paper describes the overall plan, input motion development, test procedure, test results and comparisons with pre-test analysis

Flow-induced vibration phenomenon in a Mark III TRIGA reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, C K; Whittemore, W L; Kim, B S; Lee, J B; Blevins, R D; Burton, T E [Korea Atomic Energy Research Institute, Seoul (Korea, Republic of); General Atomic Company, San Diego, CA (United States)

1976-07-01

The Mark III TRIGA reactor with hexagonal fuel spacing is capable of operating at 2.0 MW. The Mark III at San Diego operated without core cooling problems or vibration at power levels up to 2.0 MW. All Mark III reactors have operated trouble-free up to 1.0 MW. The Mark III TRIGA in Korea was installed in 1972 and operated many months without trouble at 2.0 MW. During this period core changes including addition of new fuel were made. Eighteen months after startup, a coolant flow-induced vibration was observed for the first time at a power of 1.5 MW. A lengthy series of tests showed that it was not possible to establish a core configuration that permitted vibration-free operation for power levels in the range 1.5 - 2.0 MW. Observations during the tests confirmed that standing waves in the reactor tank water coupled the source within the core to the shield structure and surrounding building. Analysis of the data indicates strongly that the source of the vibration is the creation and collapse of bubbles with the core acting as a resonator. A substantially increased flow of coolant through the upper grid plate is expected to eliminate the vibration phenomenon and permit trouble-free operation at power up to 2.0 MW. In an attempt to seek a remedy, both GAC and KAERI have independently developed designs for upper grid plates. KAERI has constructed and installed an interim version of the standard grid plate which was calculated to provide 25% more coolant flow and mounted high so as to provide less restriction to flow around the upper fittings of the fuel elements. A substantial reduction in vibration was observed. No vibration was observed at any power up to 2.0 MW with cooling water at or below 20 C. A slight vibration at 1.8 MW occurred for higher cooling temperatures. The GAC grid plate design provides not only for increasing the flow area but also for streamlining the flow surfaces on the grid plate and possibly also on the top fittings of the fuel elements. It is

Flow-induced vibration phenomenon in a Mark III TRIGA reactor

International Nuclear Information System (INIS)

Lee, C.K.; Whittemore, W.L.; Kim, B.S.; Lee, J.B.; Blevins, R.D.; Burton, T.E.

1976-01-01

The Mark III TRIGA reactor with hexagonal fuel spacing is capable of operating at 2.0 MW. The Mark III at San Diego operated without core cooling problems or vibration at power levels up to 2.0 MW. All Mark III reactors have operated trouble-free up to 1.0 MW. The Mark III TRIGA in Korea was installed in 1972 and operated many months without trouble at 2.0 MW. During this period core changes including addition of new fuel were made. Eighteen months after startup, a coolant flow-induced vibration was observed for the first time at a power of 1.5 MW. A lengthy series of tests showed that it was not possible to establish a core configuration that permitted vibration-free operation for power levels in the range 1.5 - 2.0 MW. Observations during the tests confirmed that standing waves in the reactor tank water coupled the source within the core to the shield structure and surrounding building. Analysis of the data indicates strongly that the source of the vibration is the creation and collapse of bubbles with the core acting as a resonator. A substantially increased flow of coolant through the upper grid plate is expected to eliminate the vibration phenomenon and permit trouble-free operation at power up to 2.0 MW. In an attempt to seek a remedy, both GAC and KAERI have independently developed designs for upper grid plates. KAERI has constructed and installed an interim version of the standard grid plate which was calculated to provide 25% more coolant flow and mounted high so as to provide less restriction to flow around the upper fittings of the fuel elements. A substantial reduction in vibration was observed. No vibration was observed at any power up to 2.0 MW with cooling water at or below 20 C. A slight vibration at 1.8 MW occurred for higher cooling temperatures. The GAC grid plate design provides not only for increasing the flow area but also for streamlining the flow surfaces on the grid plate and possibly also on the top fittings of the fuel elements. It is

Upper-Level Waves of Synoptic Scale at Midlatitudes

Science.gov (United States)

Rivest, Chantal

1990-01-01

Upper-level waves of synoptic scale are important dynamical entities at midlatitudes. They often induce surface cyclogenesis (cf. Peterssen and Smebye, 1971), and their life duration is typically longer than time scales for disruption by the ambient shear (Sanders, 1988). The objectives of the present thesis are to explain the maintenance and genesis of upper-level synoptic-scale waves in the midlatitude flow. We develop an analytical model of waves on generalized Eady basic states that have uniform tropospheric and stratospheric potential vorticity, but allow for the decay of density with height. The Eady basic state represents the limiting case of infinite stratospheric stability and constant density. We find that the Eady normal mode characteristics hold in the presence of realistic tropopause and stratosphere. In particular, the basic states studied support at the synoptic scale upper-level normal modes. These modes provide simple models for the dynamics of upper-level synoptic-scale waves, as waves supported by the large latitudinal gradients of potential vorticity at the tropopause. In the presence of infinitesimal positive tropospheric gradients of potential vorticity, the upper-level normal mode solutions no longer exist, as was demonstrated in Green (1960). Disappearance of the normal mode solution when a parameter changes slightly represents a dilemma that we seek to understand. We examine what happens to the upper-level normal modes in the presence of tropospheric gradients of potential vorticity in a series of initial -value experiments. Our results show that the normal modes become slowly decaying quasi-modes. Mathematically the quasi-modes consist of a superposition of singular modes sharply peaked in the phase speed domain, and their decay proceeds as the modes interfere with one another. We repeat these experiments in basic states with a smooth tropopause in the presence of tropospheric and stratospheric gradients, and similar results are obtained

Population of vibrational levels of carbon dioxide by cylindrical fast ionization wave

KAUST Repository

Levko, Dmitry

2017-09-08

The population of vibrational levels of carbon dioxide (CO2) by a cylindrical fast ionization wave is analyzed using a one-dimensional Particle-in-Cell Monte Carlo collisions model. The model takes into account the inelastic electron-neutral collisions as well as the super-elastic collisions between electrons and excited species. We observe an efficient population of only the first two levels of the symmetric and asymmetric vibrational modes of CO2 by means of a fast ionization wave. The excitation of other higher vibrational modes by the fast ionization wave is inefficient. Additionally, we observe a strong influence of the secondary electron emission on the population of vibrational states of CO2. This effect is associated with the kinetics of high energy electrons generated in the cathode sheath.

Assessing Upper-Level Winds on Day-of-Launch

Science.gov (United States)

Bauman, William H., III; Wheeler, Mark M.

2012-01-01

On the day-or-launch. the 45th Weather Squadron Launch Weather Officers (LWOS) monitor the upper-level winds for their launch customers to include NASA's Launch Services Program (LSP). During launch operations, the payload launch team sometimes asks the LWO if they expect the upper level winds to change during the countdown but the LWOs did not have the capability to quickly retrieve or display the upper-level observations and compare them to the numerical weather prediction model point forecasts. The LWOs requested the Applied Meteorology Unit (AMU) develop a capability in the form of a graphical user interface (GUI) that would allow them to plot upper-level wind speed and direction observations from the Kennedy Space Center Doppler Radar Wind Profilers and Cape Canaveral Air Force Station rawinsondes and then overlay model point forecast profiles on the observation profiles to assess the performance of these models and graphically display them to the launch team. The AMU developed an Excel-based capability for the LWOs to assess the model forecast upper-level winds and compare them to observations. They did so by creating a GUI in Excel that allows the LWOs to first initialize the models by comparing the O-hour model forecasts to the observations and then to display model forecasts in 3-hour intervals from the current time through 12 hours.

Vibrational energy transfer in selectively excited diatomic molecules. [Relaxation rates, self-relaxation, upper limits

Energy Technology Data Exchange (ETDEWEB)

Dasch, C.J.

1978-09-01

Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295/sup 0/K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295/sup 0/K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ..delta..J transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references.

A new vibrational level of the H2+ molecular ion

International Nuclear Information System (INIS)

Carbonell, J.; Lazauskas, R.; Delande, D.; Hilico, L.; Kilic, S.; Hilico, L.; Kilic, S.

2003-01-01

A new vibrational level of the molecular ion H 2 + with binding energy of 1.09 x 10 -9 a.u. ∼ 30 neV below the first dissociation limit is predicted, using highly accurate numerical non-relativistic quantum calculations, which go beyond the Born-Oppenheimer approximation. It is the first-excited vibrational level v=1 of the 2pσ u electronic state, antisymmetric with respect to the exchange of the two protons, with orbital angular momentum L=0. It manifests itself as a huge p - H scattering length of a = 750 ± 5 Bohr radii. (authors)

A case report of vibration-induced hand comorbidities in a postwoman

Directory of Open Access Journals (Sweden)

Violante Francesco S

2011-02-01

Full Text Available Abstract Background Prolonged exposure to hand-transmitted vibration is associated with an increased occurrence of symptoms and signs of disorders in the vascular, neurological and osteoarticular systems of the upper limbs. However, the available epidemiological evidence is derived from studies on high vibration levels caused by vibratory tools, whereas little is known about possible upper limb disorders caused by chronic exposure to low vibration levels emitted by fixed sources. Case presentation We present the case of a postwoman who delivered mail for 15 years using a low-powered motorcycle. The woman was in good health until 2002, when she was diagnosed with bilateral Raynaud's phenomenon. In March 2003 a bilateral carpal tunnel syndrome was electromyographically diagnosed; surgical treatment was ineffective. Further examinations in 2005 highlighted the presence of chronic tendonitis (right middle finger flexor. Risk assessment From 1987, for 15 years, our patient rode her motorcycle for 4 h/day, carrying a load of 20-30 kg. For about a quarter of the time she drove over country roads. Using the information collected about the tasks carried out every day by the postwoman and some measurements performed on both handles of the motorcycle, as well as on both iron parts of the handlebars, we reconstructed the woman's previous exposure to hand-arm vibration. 8-hour energy-equivalent frequency weighted acceleration was about 2.4 m/s2. The lifetime dose was 1.5 × 109(m2/s4hd. Conclusions The particular set of comorbidities presented by our patient suggests a common pathophysiological basis for all the diseases. Considering the level of exposure to vibrations and the lack of specific knowledge on the effects of vibration in women, we hypothesize an association between the work exposure and the onset of the diseases.

Characterization of Friction Joints Subjected to High Levels of Random Vibration

Science.gov (United States)

deSantos, Omar; MacNeal, Paul

2012-01-01

This paper describes the test program in detail including test sample description, test procedures, and vibration test results of multiple test samples. The material pairs used in the experiment were Aluminum-Aluminum, Aluminum- Dicronite coated Aluminum, and Aluminum-Plasmadize coated Aluminum. Levels of vibration for each set of twelve samples of each material pairing were gradually increased until all samples experienced substantial displacement. Data was collected on 1) acceleration in all three axes, 2) relative static displacement between vibration runs utilizing photogrammetry techniques, and 3) surface galling and contaminant generation. This data was used to estimate the values of static friction during random vibratory motion when "stick-slip" occurs and compare these to static friction coefficients measured before and after vibration testing.

Influence of Tire Characteristics of Interurban Taxis on Exposure Level to Drivers Whole-Body Vibrations

Directory of Open Access Journals (Sweden)

Milad Derakhshanjazari

2016-03-01

Full Text Available Introduction: Taxi drivers’ exposure to repeat whole-body vibrations can cause back pain and digestive disorders. Since this type of vibration depends on the car components, this study was carried out to determine the influence of tire characteristics on the amount of whole-body vibrations transmitted to the Peugeot 405 taxi drivers. Methods: In this experimental study, vibration characteristics were measured according to the ISO2631-1 with each of the statuses: tubeless tires fixed and fluid in it (normal air or nitrogen and also the fluid in the tires fixed with tubes or tubeless on asphalt-paved road. Other variables including tire pressure, engine speed, road gradient, number of passengers, springs, and shock absorbers were kept constant. Then the effect of changes was analyzed using an appropriate statistical test. Results: After changing nitrogen to normal air and tubeless tires to tube, the average of RMS in Z-axis, eight-hour equivalent acceleration A(8 and crest factor were reduced (P 0.9 m/s2 to caution zone (0.45-0.9 m/s2 with a value of 0.8 m/s2. Conclusions: The amount of vibration transmitted to the whole body is sensitive to existence of tubes and tires inflation so that we can reduce the amount of whole-body vibration to lower than the upper limit of the health risk by changing the characteristics of the tire

State resolved vibrational relaxation modeling for strongly nonequilibrium flows

Science.gov (United States)

Boyd, Iain D.; Josyula, Eswar

2011-05-01

Vibrational relaxation is an important physical process in hypersonic flows. Activation of the vibrational mode affects the fundamental thermodynamic properties and finite rate relaxation can reduce the degree of dissociation of a gas. Low fidelity models of vibrational activation employ a relaxation time to capture the process at a macroscopic level. High fidelity, state-resolved models have been developed for use in continuum gas dynamics simulations based on computational fluid dynamics (CFD). By comparison, such models are not as common for use with the direct simulation Monte Carlo (DSMC) method. In this study, a high fidelity, state-resolved vibrational relaxation model is developed for the DSMC technique. The model is based on the forced harmonic oscillator approach in which multi-quantum transitions may become dominant at high temperature. Results obtained for integrated rate coefficients from the DSMC model are consistent with the corresponding CFD model. Comparison of relaxation results obtained with the high-fidelity DSMC model shows significantly less excitation of upper vibrational levels in comparison to the standard, lower fidelity DSMC vibrational relaxation model. Application of the new DSMC model to a Mach 7 normal shock wave in carbon monoxide provides better agreement with experimental measurements than the standard DSMC relaxation model.

Enhancing Bone Accretion Using Short Duration, Low-Level Mechanical Vibrations

National Research Council Canada - National Science Library

Judex, Stefan

2005-01-01

.... In this second annual report, data are presented that indicate that the efficacy of extremely low-level whole-body mechanical vibrations can be enhanced by altering the number of daily loading...

Coherent excitation of vibrational levels using ultra short pulses

CSIR Research Space (South Africa)

De Clercq, LE

2009-07-01

Full Text Available population in a specific vibrational level. We used two approaches to do this, in the one model we used Von Neumann’s equations and the other the Optical Bloch equations (OBE’s). In this poster presentation the Optical Bloch model was used to do...

STUDY OF THE VIBRATION LEVEL IN CASE OF MANUFACTURING ON A CNC MACHINE-TOOL

Directory of Open Access Journals (Sweden)

Ioan Călin ROȘCA

2015-12-01

Full Text Available The paper presents the results of an experimental research performed on a CNC machine tool type ISEL-GFV considering the vibration level developed during the manufacturing of different pieces of particleboard at six processing regimes. There were recorded signals on both time and frequency domains on the three main directions. Based on recorded data there are presented the main conclusions referring to the level of vibrations and the frequencies associated to the highest levels.

Spectroscopic diagnostics of the vibrational population in the ground state of H2 and D2 molecules

International Nuclear Information System (INIS)

Fantz, U.; Heger, B.

1998-01-01

A diagnostic method has been evaluated for measuring the relative vibrational ground-state population of molecular hydrogen and deuterium. It is based on the analysis of the diagonal Fulcher bands · 3 Π u →a 3 Σ g + ) and the Franck-Condon principle of excitation. The validity of the underlying assumptions was verified by experiments in microwave discharges and the method is recommended for application in divertor plasmas in controlled fusion experiments. By attributing a vibrational temperature T vib to the ground-state electronic level (X 1 Σ g + ) and assuming population via the Franck-Condon principle, the upper Fulcher state vibrational distribution can be derived theoretically with T vib as parameter. Comparison with experimentally derived upper-state population gives the corresponding T vib of the ground state. The Franck-Condon factors for the · 3 Π 1 Σ g + and · 3 Π u →a 3 Σ g + transitions have been calculated for both hydrogen and deuterium from molecular constants using the FCFRKR code. The method has been applied to low pressure H 2 /He and D 2 /He microwave plasmas, showing good agreement of experimentally and theoretically derived upper Fulcher state vibrational distributions. The vibrational temperatures range from 3200 K to 6800 K for H 2 and 2600 K to 4000 K for D 2 · depending on molecular density, pressure and electron temperature, but indicating nearly the same vibrational population for H 2 and D 2 for comparable plasma conditions. (author)

Study of the levels of serum cortisol and gastrin in dogs with vibration-induced injury

International Nuclear Information System (INIS)

Wei Zikun

2005-01-01

Objective: To study the changes of levels of serum cortisol and gastrin in dogs with vibration-induced injury for providing better treatment regimen. Methods: In this experiment, 8 or 10 domestic dogs were placed on each of four sites away from explosion center about 0, 100, 200, 300 meters respectively. The dogs were standing uncontrolled or lying right side down under anesthesia. Serum cortisol and gastrin levels were detected with RIA both before and after explosion. Results: The levels of serum cortisol and gastrin began to fall about 24 hours after explosion. The serum levels of cortisol were still decreased significantly after 9 days and 17 days. Conclusion: The levels of the serum cortisol declined when the animals were injured by vibration. Detection of serum cortisol levels might lead to definitive diagnosis and supplemental treatment with cortical hormones for vibration-induced injury. (authors)

Observations Of General Learning Patterns In An Upper-Level Thermal Physics Course

Science.gov (United States)

Meltzer, David E.

2009-11-01

I discuss some observations from using interactive-engagement instructional methods in an upper-level thermal physics course over a two-year period. From the standpoint of the subject matter knowledge of the upper-level students, there was a striking persistence of common learning difficulties previously observed in students enrolled in the introductory course, accompanied, however, by some notable contrasts between the groups. More broadly, I comment on comparisons and contrasts regarding general pedagogical issues among different student sub-populations, for example: differences in the receptivity of lower- and upper-level students to diagrammatic representations; varying receptivity to tutorial-style instructional approach within the upper-level population; and contrasting approaches to learning among physics and engineering sub-populations in the upper-level course with regard to use of symbolic notation, mathematical equations, and readiness to employ verbal explanations.

Efficient cooling of quantized vibrations using a four-level configuration

Science.gov (United States)

Yan, Lei-Lei; Zhang, Jian-Qi; Zhang, Shuo; Feng, Mang

2016-12-01

Cooling vibrational degrees of freedom down to ground states is essential to observation of quantum properties of systems with mechanical vibration. We propose two cooling schemes employing four internal levels of the systems, which achieve the ground-state cooling in an efficient fashion by completely deleting the carrier and first-order blue-sideband transitions. The schemes, based on quantum interference and Stark-shift gates, are robust to fluctuations of laser intensity and frequency. The feasibility of the schemes is justified using current laboratory technology. In practice, our proposal readily applies to a nanodiamond nitrogen-vacancy center levitated in an optical trap or attached to a cantilever.

Computation of expectation values from vibrational coupled-cluster at the two-mode coupling level

DEFF Research Database (Denmark)

Zoccante, Alberto; Seidler, Peter; Christiansen, Ove

2011-01-01

In this work we show how the vibrational coupled-cluster method at the two-mode coupling level can be used to calculate zero-point vibrational averages of properties. A technique is presented, where any expectation value can be calculated using a single set of Lagrangian multipliers computed...

Validity and inter-observer reliability of subjective hand-arm vibration assessments

NARCIS (Netherlands)

Coenen, P.; Formanoy, M.; Douwes, M.; Bosch, T.; Kraker, H. de

2014-01-01

Exposure to mechanical vibrations at work (e.g., due to handling powered tools) is a potential occupational risk as it may cause upper extremity complaints. However, reliable and valid assessment methods for vibration exposure at work are lacking. Measuring hand-arm vibration objectively is often

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.

Van der Waals potential and vibrational energy levels of the ground state radon dimer

Science.gov (United States)

Sheng, Xiaowei; Qian, Shifeng; Hu, Fengfei

2017-08-01

In the present paper, the ground state van der Waals potential of the Radon dimer is described by the Tang-Toennies potential model, which requires five essential parameters. Among them, the two dispersion coefficients C6 and C8 are estimated from the well determined dispersion coefficients C6 and C8 of Xe2. C10 is estimated by using the approximation equation that C6C10/C82 has an average value of 1.221 for all the rare gas dimers. With these estimated dispersion coefficients and the well determined well depth De and Re the Born-Mayer parameters A and b are derived. Then the vibrational energy levels of the ground state radon dimer are calculated. 40 vibrational energy levels are observed in the ground state of Rn2 dimer. The last vibrational energy level is bound by only 0.0012 cm-1.

The acute effects of stretching with vibration on dynamic flexibility in young female gymnasts.

Science.gov (United States)

Johnson, Aaron W; Warcup, Caisa N; Seeley, Matthew K; Eggett, Dennis; Feland, Jeffery B

2018-01-10

While stretching with vibration has been shown to improve static flexibility; the effect of stretching with vibration on dynamic flexibility is not well known. The purpose of this study was to examine the effectiveness of stretching with vibration on acute dynamic flexibility and jump height in novice and advanced competitive female gymnasts during a split jump. Female gymnast (n=27, age: 11.5 ± 1.7 years, Junior Olympic levels 5-10) participated in this cross-over study. Dynamic flexibility during gymnastic split jumps were video recorded and analyzed with Dartfish software. All participants completed both randomized stretching protocols with either the vibration platform turned on (VIB) (frequency of 30 Hz and 2 mm amplitude) or off (NoVIB) separated by 48 h. Participants performed 4 sets of three stretches on the vibration platform. Each stretch was held for 30 s with 5 s rest for a total of 7 min of stretch. Split jump flexibility decreased significantly from pre to post measurement in both VIB (-5.8°±5.9°) (p<0.001) and NoVIB (-2.6°±6.1°) (p=0.041) conditions (adjusted for gymnast level). This effect was greatest in lower skill level gymnasts (p=0.003), while the highest skill level gymnasts showed no significant decrease in the split jump (p=0.105). Jump height was not significantly different between conditions (p=0.892) or within groups (p=0.880). An acute session of static stretching with or without vibration immediately before performance does not alter jump height. Stretching with vibration immediately prior to gymnastics competition decreases split jump flexibility in lower level gymnasts more than upper level gymnasts.

Teaching Astrophysics to Upper Level Undergraduates

Science.gov (United States)

Van Dorn Bradt, Hale

2010-03-01

A Socratic peer-instruction method for teaching upper level undergraduates is presented. Basically, the instructor sits with the students and guides their presentations of the material. My two textbooks* (on display) as well as many others are amenable to this type of teaching. *Astronomy Methods - A Physical Approach to Astronomical Observations (CUP 2004) *Astrophysics Processes-The Physics of Astronomical Phenomena (CUP 2008)

Wind turbine blades condition assessment based on vibration measurements and the level of an empirically decomposed feature

International Nuclear Information System (INIS)

Abouhnik, Abdelnasser; Albarbar, Alhussein

2012-01-01

Highlights: ► We used finite element method to model wind turbine induced vibration characteristics. ► We developed a technique for eliminating wind turbine’s vibration modulation problems. ► We use empirical mode decomposition to decompose the vibration into its fundamental elements. ► We show the area under shaft speed is a good indicator for assessing wind blades condition. ► We validate the technique under different wind turbine speeds and blade (cracks) conditions. - Abstract: Vibration based monitoring techniques are well understood and widely adopted for monitoring the condition of rotating machinery. However, in the case of wind turbines the measured vibration is complex due to the high number of vibration sources and modulation phenomenon. Therefore, extracting condition related information of a specific element e.g. blade condition is very difficult. In the work presented in this paper wind turbine vibration sources are outlined and then a three bladed wind turbine vibration was simulated by building its model in the ANSYS finite element program. Dynamic analysis was performed and the fundamental vibration characteristics were extracted under two healthy blades and one blade with one of four cracks introduced. The cracks were of length (10 mm, 20 mm, 30 mm and 40 mm), all had a consistent 3 mm width and 2 mm depth. The tests were carried out for three rotation speeds; 150, 250 and 360 r/min. The effects of the seeded faults were revealed by using a novel approach called empirically decomposed feature intensity level (EDFIL). The developed EDFIL algorithm is based on decomposing the measured vibration into its fundamental components and then determines the shaft rotational speed amplitude. A real model of the simulated wind turbine was constructed and the simulation outcomes were compared with real-time vibration measurements. The cracks were seeded sequentially in one of the blades and their presence and severity were determined by decomposing

The impact of accelerometer mounting methods on the level of vibrations recorded at ground surface

Directory of Open Access Journals (Sweden)

Krzysztof Czech

2014-08-01

Full Text Available The paper presents the results of field research based on the measurements of accelerations recorded at ground surface. The source of the vibration characterized by high repetition rate of pulse parameters was light falling weight deflectometer ZFG-01. Measurements of vibrations have been carried out using top quality high-precision measuring system produced by Brüel&Kiær. Accelerometers were mounted on a sandy soil surface at the measuring points located radially at 5-m and 10-m distances from the source of vibration. The paper analyses the impact that the method of mounting accelerometers on the ground has on the level of the recorded values of accelerations of vibrations. It has been shown that the method of attaching the sensor to the surface of the ground is crucial for the credibility of the performed measurements.[b]Keywords[/b]: geotechnics, surface vibrations, ground, vibration measurement

Noise and Vibrations Measurements. External noise and vibrations measurements for offshore SODAR application

International Nuclear Information System (INIS)

Ormel, F.T.; Eecen, P.J.; Herman, S.A.

2003-10-01

The partners in the WISE project investigate whether application of the SODAR (sonic detection and ranging) measurement technique in wind energy experimental work is feasible as a replacement for cup anemometers, wind direction sensors and tall meteorological masts. In Work Package 2 of the WISE project extensive controlled experiments with the SODAR are performed. For example SODAR measurements are compared with measurements from nearby masts and different brands of SODARs are compared. Part of the work package is the measurement of vibration and noise on an offshore SODAR system. The results of these measurements are presented in this report. ECN performed measurements at an offshore location to investigate the influence of noise and vibrations on the performance of a MiniSODAR measurement system. The aim of the measurements is to quantify the effect of these external noise and vibrations disturbances on the MiniSODAR's performance. Measurements on an identical SODAR system onshore are carried out to compare the disturbances of offshore and onshore external conditions. The effect of background noise on SODAR operation has clearly been established in literature. Therefore, measurements have been performed only to establish the absolute sound pressure levels. This is done at the Measuring Platform Noordwijk (MPN) located in the North Sea, nine kilometres out of the coast at Noordwijk, The Netherlands, and at two locations onshore. At the MPN-platform, the SODAR has been moved from the middle deck to the upper deck to diminish the influence of the diesel generator needed for the electric powering of the island. Although the absolute sound pressure level became higher at the new location, this level became lower at the most important frequencies inside the SODAR, due to the use of absorbing foam. With regards to the sound pressure level the move improved the situation. The sound pressure levels measured offshore were 6 to 15 dB higher than for the two locations

Prediction of vibration level in tunnel blasting; Tonneru kusshin happa ni yotte reiki sareru shindo no reberu yosoku ho

Energy Technology Data Exchange (ETDEWEB)

Hirata, A. [Kumamoto Industries Univ, Kumamoto (Japan); Yamamoto, M. [Asahi Chemical Industry Co. Ltd., Tokyo (Japan); Inaba, C. [Nishimatsu Construction Co. Ltd., Kanagawa (Japan); Kaneko, K. [Hokkaido Univ (Japan)

1997-08-01

For avoiding the generation of public hazard due to ground vibration causes by blasting in tunneling, it is important to devise a blasting method for ensuring the level of the ground vibration caused thereby under a limit, and an exact predication of ground vibration before blasting is desirable. In this study, the characteristics of the ground vibration caused by tunnel blasting are analyzed, and a summary of amplitude spectra calculating method is described. A theoretical analysis method for predicting the vibration level is proposed based on spectrum-multiplicative method. Vibration caused by multistage blasting in tunneling is most strong and deemed as important. When observing the process of elastic wave motion caused by multistage blasting being measured, the process can be divided into three element processes in frequency area as vibration source spectrum, transmission attenuation spectrum and frequency response function vibrating test, and, with the multiplication of them, the amplitude spectra at an observation portion can be estimated. 12 refs., 12 figs.

Population of vibrational levels of carbon dioxide by cylindrical fast ionization wave

KAUST Repository

Levko, Dmitry; Pachuilo, Michael; Raja, Laxminarayan L.

2017-01-01

The population of vibrational levels of carbon dioxide (CO2) by a cylindrical fast ionization wave is analyzed using a one-dimensional Particle-in-Cell Monte Carlo collisions model. The model takes into account the inelastic electron

High-frequency, low-intensity vibrations increase bone mass and muscle strength in upper limbs, improving autonomy in disabled children.

Science.gov (United States)

Reyes, M Loreto; Hernández, Marta; Holmgren, Luz J; Sanhueza, Enrique; Escobar, Raúl G

2011-08-01

Disuse osteoporosis in children is a progressive disease that can affect quality of life. High-frequency, low-magnitude vibration (HFLMV) acts as an anabolic signal for bone and muscle. We undertook a prospective, randomized, double-blind, placebo-controlled clinical trial to assess the efficacy and safety of regional HFLMV in disabled children. Sixty-five children 6 to 9 year of age were randomized into three groups: placebo, 60 Hz, and 90 Hz. In the two active groups, a 0.3-g mechanical vibration was delivered to the radii and femurs for 5 minutes each day. After 6 months, the main endpoint was bone mineral density (BMD) at the ultradistal radius (UDR), 33% radii (33%R), and femoral necks (FN). Secondary endpoints were area and bone mineral content (BMC) at the UDR, 33%R, and FN; grip force of the upper and lower limbs; motor function; and PedsQL evaluation. An intention-to-treat analysis was used. Fifty-seven children (88%) completed the protocol. A significant increase was observed in the 60-Hz group relative to the other groups in BMD at the UDR (p = .011), in grip force of the upper limbs (p = .035), and in the "daily activities item" (p = .035). A mixed model to evaluate the response to intervention showed a stronger effect of 60 Hz on patients with cerebral palsy on the UDR and that between-subject variability significantly affected the response. There were no reported side effects of the intervention. This work provides evidence that regional HFLMV is an effective and safe strategy to improve bone mass, muscle strength, and possibly independence in children with motor disabilities. Copyright © 2011 American Society for Bone and Mineral Research.

[Farmacological effect of retabolil on aldosterone level and arterial pressure in rats under the action of vibrations].

Science.gov (United States)

Obut, T A; Ovsiukova, M V; Egorova, S A; Érdynieva, T A; Dement'eva, T Iu; Obut, E T

2014-01-01

The experiments were performed on male rats, which were subjected to single and multiply repeated vibrations (low-frequency, horizontal, high-amplitude) analogous to the action of motor transport vibrations. It is established that the administration of retabolil produces a hypotensive effect and blocks the vibration-induced increase in the level of hypertensive hormone aldosterone. Under conditions of the multiply repeated action of vibrations, both effects were realized via micro-opioid receptors. In the case of a single action, these receptors were only involved in a hypotensive effect but not mediated in aldosterone suppression. Both these effects were absent in the control group of animals (not subjected to vibrations). Therefore, retabolil can be used as a hypotensive and aldosterone-blocking drug for vibration-induced hypertension in animals and, probably, in humans.

Hand-arm vibration in tropical rain forestry workers.

Science.gov (United States)

Futatsuka, M; Inaoka, T; Ohtsuka, R; Sakurai, T; Moji, K; Igarashi, T

1995-01-01

Working conditions and health hazards including vibration syndrome related to forestry work using chain-saws were studied in Papua New Guinea and Indonesia. The subjects comprised 291 workers including 97 chain-saw operators. The health examination consisted of peripheral circulatory and sensory tests in the upper extremities. The vibration spectrum measured at the handle of the chain-saw indicated that these acceleration levels would lead to a moderately high risk of hand-arm vibration syndrome (HAVS). The peripheral circulatory function tests revealed dysfunction after more than five years vibration exposure. However, in general, the results of the function tests and subjective complaints showed fewer health problems compared to those of Japanese forestry workers. The reason of such differences of vibration effects seem to be the following: (1) warmer climate (more than 25 degrees C throughout the year), (2) young workers and short work experience. (3) short time vibration exposures on working days in the natural forests, (4) seasonal changes in logging work (5) healthy workers effects. Thus, we found no clear evidence that the workers of our study suffered from HAVS. A principal component analysis was applied. The factor score of the components of the reactive dynamics of peripheral circulation differed significantly after more than five years' exposure. On the other hand, we cannot deny the possibility that subclinical dysfunction of peripheral circulation may be caused by chain-saw operation in the tropics in future. Further investigations on the HAVS among forestry workers in the tropic environment are needed.

Overtone vibrational spectroscopy in H2-H2O complexes: a combined high level theoretical ab initio, dynamical and experimental study.

Science.gov (United States)

Ziemkiewicz, Michael P; Pluetzer, Christian; Nesbitt, David J; Scribano, Yohann; Faure, Alexandre; van der Avoird, Ad

2012-08-28

First results are reported on overtone (v(OH) = 2 ← 0) spectroscopy of weakly bound H(2)-H(2)O complexes in a slit supersonic jet, based on a novel combination of (i) vibrationally mediated predissociation of H(2)-H(2)O, followed by (ii) UV photodissociation of the resulting H(2)O, and (iii) UV laser induced fluorescence on the nascent OH radical. In addition, intermolecular dynamical calculations are performed in full 5D on the recent ab initio intermolecular potential of Valiron et al. [J. Chem. Phys. 129, 134306 (2008)] in order to further elucidate the identity of the infrared transitions detected. Excellent agreement is achieved between experimental and theoretical spectral predictions for the most strongly bound van der Waals complex consisting of ortho (I = 1) H(2) and ortho (I = 1) H(2)O (oH(2)-oH(2)O). Specifically, two distinct bands are seen in the oH(2)-oH(2)O spectrum, corresponding to internal rotor states in the upper vibrational manifold of Σ and Π rotational character. However, none of the three other possible nuclear spin modifications (pH(2)-oH(2)O, pH(2)-pH(2)O, or oH(2)-pH(2)O) are observed above current signal to noise level, which for the pH(2) complexes is argued to arise from displacement by oH(2) in the expansion mixture to preferentially form the more strongly bound species. Direct measurement of oH(2)-oH(2)O vibrational predissociation in the time domain reveals lifetimes of 15(2) ns and <5(2) ns for the Σ and Π states, respectively. Theoretical calculations permit the results to be interpreted in terms of near resonant energy levels and intermolecular alignment of the H(2) and H(2)O wavefunctions, providing insight into predissociation dynamical pathways from these metastable levels.

Progressive Derechos in the Presence of Closed Upper-level Subtropical Anticyclones

Science.gov (United States)

Guastini, C.; Bosart, L. F.

2013-12-01

Progressive derechos are a type of long-lived mesoscale convective system that produces large swaths of wind damage. In contrast to their serial derecho counterparts, which form in association with extratropical cyclones, progressive derechos often occur in the presence of benign synoptic conditions on the poleward side of closed upper-level subtropical anticyclones. Forecasters have been known to struggle predicting progressive derechos with any certainty due to the common lack of large-scale support for severe weather in regimes dominated by anticyclonic conditions. This study will classify a group of days on which there was a closed upper-level anticyclone over the United States and a progressive derecho did not occur and a group of days on which there was a closed upper-level anticyclone over the United States and a progressive derecho did occur, examine the synoptic environments of the two groups, and identify derecho null cases. By analyzing the null cases, derecho failure modes will be determined, which will help forecaster situational awareness and reveal the science behind the environmental conditions necessary for, and detrimental to, derecho development. This presentation will include climatologies of both derechos and closed upper-level anticyclones over the United States for June, July, and August of the years 1994-2013 (the modern radar era). The presentation will also include closed anticyclone-relative composites of both derecho cases and derecho null cases. The composites will elucidate which conditions are necessary for, and which are detrimental to, derecho development. The hypothesis is that derecho failure days occur due either to the lack of a triggering mechanism or other phenomena working against convective development such as a strong capping inversion or transverse ageostrophic circulations around an upper-level jet creating subsidence in an otherwise favorable environment. A representative case study will be included to highlight a common

Full-Dimensional Quantum Calculations of Vibrational Levels of NH4(+) and Isotopomers on An Accurate Ab Initio Potential Energy Surface.

Science.gov (United States)

Yu, Hua-Gen; Han, Huixian; Guo, Hua

2016-04-14

Vibrational energy levels of the ammonium cation (NH4(+)) and its deuterated isotopomers are calculated using a numerically exact kinetic energy operator on a recently developed nine-dimensional permutation invariant semiglobal potential energy surface fitted to a large number of high-level ab initio points. Like CH4, the vibrational levels of NH4(+) and ND4(+) exhibit a polyad structure, characterized by a collective quantum number P = 2(v1 + v3) + v2 + v4. The low-lying vibrational levels of all isotopomers are assigned and the agreement with available experimental data is better than 1 cm(-1).

Vibration Analysis of Beam and Block Precast Slab System due to Human Vibrations

Science.gov (United States)

Chik, T. N. T.; Kamil, M. R. H.; Yusoff, N. A.

2018-04-01

Beam and block precast slabs system are very efficient which generally give maximum structural performance where their voids based on the design of the unit soffit block allow a significant reduction of the whole slab self-weight. Initially for some combinations of components or the joint connection of the structural slab, this structural system may be susceptible to excessive vibrations that could effects the performance and also serviceability. Dynamic forces are excited from people walking and jumping which produced vibrations to the slab system in the buildings. Few studies concluded that human induced vibration on precast slabs system may be harmful to structural performance and mitigate the human comfort level. This study will investigate the vibration analysis of beam and block precast slab by using finite element method at the school building. Human activities which are excited from jumping and walking will induce the vibrations signal to the building. Laser Doppler Vibrometer (LDV) was used to measure the dynamic responses of slab towards the vibration sources. Five different points were assigned specifically where each of location will determine the behaviour of the entire slabs. The finite element analyses were developed in ABAQUS software and the data was further processed in MATLAB ModalV to assess the vibration criteria. The results indicated that the beam and block precast systems adequate enough to the vibration serviceability and human comfort criteria. The overall vibration level obtained was fell under VC-E curve which it is generally under the maximum permissible level of vibrations. The vibration level on the slab is acceptable within the limit that have been used by Gordon.

Experimental Research on the Influence of Vibration on Fingers Mobility

Directory of Open Access Journals (Sweden)

Radu Panaitescu-Liess

2013-09-01

Full Text Available In many industrial activities the human body is exposed to vibrations transmitted through the hand-arm system. A long exposure to these vibrations can cause various health problems of blood vessels, nerves, muscles, bones, joints and upper limb [1]. This paper presents some considerations about the influence of vibration on finger joints mobility. I used a MediTouch system which consists of a motion capture device (an ergonomic glove and a dedicated software.

Short-Term Effects of Whole-Body Vibration Combined with Task-Related Training on Upper Extremity Function, Spasticity, and Grip Strength in Subjects with Poststroke Hemiplegia: A Pilot Randomized Controlled Trial.

Science.gov (United States)

Lee, Jung-Sun; Kim, Chang-Yong; Kim, Hyeong-Dong

2016-08-01

The aim of this study was to determine the effect of whole-body vibration training combined with task-related training on arm function, spasticity, and grip strength in subjects with poststroke hemiplegia. Forty-five subjects with poststroke were randomly allocated to 3 groups, each with 15 subjects as follows: control group, whole-body vibration group, and whole-body vibration plus task-related training group. Outcome was evaluated by clinical evaluation and measurements of the grip strength before and 4 weeks after intervention. Our results show that there was a significantly greater increase in the Fugl-Meyer scale, maximal grip strength of the affected hand, and grip strength normalized to the less affected hand in subjects undergoing the whole-body vibration training compared with the control group after the test. Furthermore, there was a significantly greater increase in the Wolf motor function test and a decrease in the modified Ashworth spasticity total scores in subjects who underwent whole-body vibration plus task-related training compared with those in the other 2 groups after the test. The findings indicate that the use of whole-body vibration training combined with task-related training has more benefits on the improvement of arm function, spasticity, and maximal grip strength than conventional upper limb training alone or with whole-body vibration in people with poststroke hemiplegia.

Torsional, Vibrational and Vibration-Torsional Levels in the S_{1} and Ground Cationic D_{0}^{+} States of Para-Fluorotoluene

Science.gov (United States)

Gardner, Adrian M.; Tuttle, William Duncan; Whalley, Laura E.; Claydon, Andrew; Carter, Joseph H.; Wright, Timothy G.

2017-06-01

The S_{1} electronic state and ground state of the cation of para-fluorotoluene (pFT) have been investigated using resonance-enhanced multiphoton ionization (REMPI) spectroscopy and zero-kinetic-energy (ZEKE) spectroscopy. Here we focus on the low wavenumber region where a number of "pure" torsional, fundamental vibrational and vibration-torsional levels are expected; assignments of observed transitions are discussed, which are compared to results of published work on toluene (methylbenzene) from the Lawrance group. The similarity in the activity observed in the excitation spectrum of the two molecules is striking. A. M. Gardner, W. D. Tuttle, L. Whalley, A. Claydon, J. H. Carter and T. G. Wright, J. Chem. Phys., 145, 124307 (2016). J. R. Gascooke, E. A. Virgo, and W. D. Lawrance J. Chem. Phys., 143, 044313 (2015).

A study on the contribution of body vibrations to the vibratory sensation induced by high-level, complex low-frequency noise

Directory of Open Access Journals (Sweden)

Yukio Takahashi

2011-01-01

Full Text Available To investigate the contribution of body vibrations to the vibratory sensation induced by high-level, complex low-frequency noise, we conducted two experiments. In Experiment 1, eight male subjects were exposed to seven types of low-frequency noise stimuli: two pure tones [a 31.5-Hz, 100-dB(SPL tone and a 50-Hz, 100-dB(SPL tone] and five complex noises composed of the pure tones. For the complex noise stimuli, the sound pressure level of one tonal component was 100 dB(SPL and that of another one was either 90, 95, or 100 dB(SPL. Vibration induced on the body surface was measured at five locations, and the correlation with the subjective rating of the vibratory sensation at each site of measurement was examined. In Experiment 2, the correlation between the body surface vibration and the vibratory sensation was similarly examined using seven types of noise stimuli composed of a 25-Hz tone and a 50-Hz tone. In both the experiments, we found that at the chest and the abdomen, the rating of the vibratory sensation was in close correlation with the vibration acceleration level (VAL of the body surface vibration measured at each corresponding location. This was consistent with our previous results and suggested that at the trunk of the body (the chest and the abdomen, the mechanoreception of body vibrations plays an important role in the experience of the vibratory sensation in persons exposed to high-level low-frequency noise. At the head, however, no close correlation was found between the rating of the vibratory sensation and the VAL of body surface vibration. This suggested that at the head, the perceptual mechanisms of vibration induced by high-level low-frequency noise were different from those in the trunk of the body.

Triangle bracing system to reduce the vibration level of cooling tower – case study in PT Star Energy Geothermal (Wayang Windu Ltd – Indonesia

Directory of Open Access Journals (Sweden)

Effendi Tri Bahtiar

2018-06-01

Full Text Available Periodical control and measurement revealed that vibration level of motor and gearbox which was supported by Cooling Tower Unit 1 at PT Star Energy Geothermal (Wayang Windu Ltd was significantly increasing since 2013. The vibration was not caused by machinery component failure, but induced by resonance of process flow. Decreasing stiffness of cooling tower structure was suspected causing the increasing vibration level. The physical, chemical, and mechanical properties of wood was deteriorated. The residual strength of the wood had been measured and the data was used to perform dynamic structural analysis on the cooling tower. Several scenarios of structure modification were modelled and drawn, and the best one which the most effectively reducing the vibration level among others was constructed in the field. Triangle inner structure was chosen and applied to modify the cooling tower structure to achieve stiffer and more rigid structure. The vibration level before and after structure modification were measured, and it was proved that the vibration level was significantly reduced after structure modification. Furthermore the cooling tower was not in zone D (danger anymore and the vibration level was accepted according to ISO 10816-3. Keywords: Cooling tower, Dynamic structural analysis, Geothermal power plant, Structural failure, Vibration level

Multi-Exciter Vibroacoustic Simulation of Hypersonic Flight Vibration

International Nuclear Information System (INIS)

GREGORY, DANNY LYNN; CAP, JEROME S.; TOGAMI, THOMAS C.; NUSSER, MICHAEL A.; HOLLINGSHEAD, JAMES RONALD

1999-01-01

Many aerospace structures must survive severe high frequency, hypersonic, random vibration during their flights. The random vibrations are generated by the turbulent boundary layer developed along the exterior of the structures during flight. These environments have not been simulated very well in the past using a fixed-based, single exciter input with an upper frequency range of 2 kHz. This study investigates the possibility of using acoustic ardor independently controlled multiple exciters to more accurately simulate hypersonic flight vibration. The test configuration, equipment, and methodology are described. Comparisons with actual flight measurements and previous single exciter simulations are also presented

Vibration-proof FBR type reactor

International Nuclear Information System (INIS)

Kawamura, Yutaka.

1992-01-01

In a reactor container in an FBR type reactor, an outer building and upper and lower portions of a reactor container are connected by a load transmission device made of a laminated material of rubber and steel plates. Each of the reactor container and the outer building is disposed on a lower raft disposed on a rock by way of a vibration-proof device made of a laminated material of rubber and steel plates. Vibration-proof elements for providing vertical eigen frequency of the vibration-proof system comprising the reactor building and the vibration-proof device within a range of 3Hz to 5Hz are used. That is, the peak of designed acceleration for response spectrum in the horizontal direction of the reactor structural portions is shifted to side of shorter period from the main frequency region of the reactor structure. Alternatively, rigidity of the vibration-proof elements is decreased to shift the peak to the side of long period from the main frequency region. Designed seismic force can be greatly reduced both horizontally and vertically, to reduce the wall thickness of the structural members, improve the plant economy and to ensure the safety against earthquakes. (N.H.)

Upper-Level Undergraduate Chemistry Students' Goals for Their Laboratory Coursework

Science.gov (United States)

DeKorver, Brittland K.; Towns, Marcy H.

2016-01-01

Efforts to reform undergraduate chemistry laboratory coursework typically focus on the curricula of introductory-level courses, while upper-level courses are bypassed. This study used video-stimulated recall to interview 17 junior- and senior- level chemistry majors after they carried out an experiment as part of a laboratory course. It is assumed…

Review of student difficulties in upper-level quantum mechanics

Directory of Open Access Journals (Sweden)

Chandralekha Singh

2015-09-01

Full Text Available [This paper is part of the Focused Collection on Upper Division Physics Courses.] Learning advanced physics, in general, is challenging not only due to the increased mathematical sophistication but also because one must continue to build on all of the prior knowledge acquired at the introductory and intermediate levels. In addition, learning quantum mechanics can be especially challenging because the paradigms of classical mechanics and quantum mechanics are very different. Here, we review research on student reasoning difficulties in learning upper-level quantum mechanics and research on students’ problem-solving and metacognitive skills in these courses. Some of these studies were multiuniversity investigations. The investigations suggest that there is large diversity in student performance in upper-level quantum mechanics regardless of the university, textbook, or instructor, and many students in these courses have not acquired a functional understanding of the fundamental concepts. The nature of reasoning difficulties in learning quantum mechanics is analogous to reasoning difficulties found via research in introductory physics courses. The reasoning difficulties were often due to overgeneralizations of concepts learned in one context to another context where they are not directly applicable. Reasoning difficulties in distinguishing between closely related concepts and in making sense of the formalism of quantum mechanics were common. We conclude with a brief summary of the research-based approaches that take advantage of research on student difficulties in order to improve teaching and learning of quantum mechanics.

Experimental Study of Annulus Flow for Can Combustor with Vibration Influence

Directory of Open Access Journals (Sweden)

Rami. Y. Dahham

2018-01-01

Full Text Available This paper concentrate on studying the behavior of velocity profile under the influence of different frequency (34, 48, 65 and 80 Hz in each of the upper and lower annulus of Can Combustor.An experimental rig was designed to simulate the annulus flow inside a Can Combustor.The Can Combustor tested in this study is real part collected from Al-Khairat/Iraq gas turbine power station.The velocity profiles are investigated at three positions in the annular for upper and lower region.The axial velocity and turbulence intensity are calculating with different frequency for upper and lower annulus.The results were shown that the increase of frequency lead to increase the velocity profile and large recirculation zone will build in some points.Reynolds number increasing with raise of axial velocity. Also the increasing in vibration level cause non-uniform velocity profile which affect on distribution of cooling effectiveness.

Energy Expenditure and Substrate Oxidation in Response to Side-Alternating Whole Body Vibration across Three Commonly-Used Vibration Frequencies.

Directory of Open Access Journals (Sweden)

Elie-Jacques Fares

Full Text Available There is increasing recognition about the importance of enhancing energy expenditure (EE for weight control through increases in low-intensity physical activities comparable with daily life (1.5-4 METS. Whole-body vibration (WBV increases EE modestly and could present both a useful adjuvant for obesity management and tool for metabolic phenotyping. However, it is unclear whether a "dose-response" exists between commonly-used vibration frequencies (VF and EE, nor if WBV influences respiratory quotient (RQ, and hence substrate oxidation. We aimed to investigate the EE-VF and RQ-VF relationships across three different frequencies (30, 40, and 50Hz.EE and RQ were measured in 8 healthy young adults by indirect calorimetry at rest, and subsequently during side-alternating WBV at one of 3 VFs (30, 40, and 50 Hz. Each frequency was assessed over 5 cycles of intermittent WBV (30s vibration/30s rest, separated by 5 min seated rest. During the WBV participants stood on the platform with knees flexed sufficiently to maintain comfort, prevent transmission of vibration to the upper body, and minimise voluntary physical exertion. Repeatability was assessed across 3 separate days in a subset of 4 individuals. In order to assess any sequence/habituation effect, an additional group of 6 men underwent 5 cycles of intermittent WBV (30s vibration/30s rest at 40 Hz, separated by 5 min seated rest.Side-alternating WBV increased EE relative to standing, non-vibration levels (+36%, p<0.001. However, no differences in EE were observed across VFs. Similarly, no effect of VF on RQ was found, nor did WBV alter RQ relative to standing without vibration.No relationship could be demonstrated between EE and VF in the range of 30-50Hz, and substrate oxidation did not change in response to WBV. Furthermore, the thermogenic effect of intermittent WBV, whilst robust, was quantitatively small (<2 METS.

An investigation of the processes controlling ozone in the upper stratosphere

International Nuclear Information System (INIS)

Patten, K.O. Jr.; Connell, P.S.; Kinnison, D.E.; Wuebbles, D.J.; Waters, J.; Froidevaux, L.; Slanger, T.G.

1992-01-01

Photolysis of vibrationally excited oxygen produced by ultraviolet photolysis of ozone in the upper stratosphere is incorporated into the Lawrence Livermore National Laboratory 2-D zonally averaged chemical-radiative-transport model of the troposphere and stratosphere. The importance of this potential contributor of odd oxygen to the concentration of ozone is evaluated based upon recent information on vibrational distributions of excited oxygen and upon preliminary studies of energy transfer from the excited oxygen. When the energy transfer rate constants of previous work are assumed, increases in model ozone concentrations of up to 40 percent in the upper stratosphere are found, and the ozone concentrations of the model agree with measurements, including data from the Upper Atmosphere Research Satellite. However, the increase is about 0.4 percent when the larger energy transfer rate constants suggested by more recent experimental work are applied in the model. This indicates the importance of obtaining detailed information on vibrationally excited oxygen properties, particularly the state-specific energy transfer rate constants, to evaluation of tills precess for stratospheric modeling

Molecular-level mechanisms of vibrational frequency shifts in a polar liquid.

Science.gov (United States)

Morales, Christine M; Thompson, Ward H

2011-06-16

A molecular-level analysis of the origins of the vibrational frequency shifts of the CN stretching mode in neat liquid acetonitrile is presented. The frequency shifts and infrared spectrum are calculated using a perturbation theory approach within a molecular dynamics simulation and are in good agreement with measured values reported in the literature. The resulting instantaneous frequency of each nitrile group is decomposed into the contributions from each molecule in the liquid and by interaction type. This provides a detailed picture of the mechanisms of frequency shifts, including the number of surrounding molecules that contribute to the shift, the relationship between their position and relative contribution, and the roles of electrostatic and van der Waals interactions. These results provide insight into what information is contained in infrared (IR) and Raman spectra about the environment of the probed vibrational mode. © 2011 American Chemical Society

Feedback damping of a microcantilever at room temperature to the minimum vibration amplitude limited by the noise level.

Science.gov (United States)

Kawamura, Y; Kanegae, R

2016-06-17

Cooling the vibration amplitude of a microcantilever as low as possible is important to improve the sensitivity and resolutions of various types of scanning type microscopes and sensors making use of it. When the vibration amplitude is controlled to be smaller using a feed back control system, it is known that the obtainable minimum amplitude of the vibration is limited by the floor noise level of the detection system. In this study, we demonstrated that the amplitude of the thermal vibration of a microcantilever was suppressed to be about 0.15 pmHz(-1/2), which is the same value with the floor noise level, without the assistance of external cryogenic cooling. We think that one of the reason why we could reach the smaller amplitude at room temperature is due to stiffer spring constant of the lever, which leads to higher natural frequency and consequently lower floor noise level. The other reason is considered to be due to the increase in the laser power for the diagnostics, which lead to the decrease in the signal to noise ratio determined by the optical shot noise.

The upper level of control system of electron accelerators

International Nuclear Information System (INIS)

Gribov, I.V.; Nedeoglo, F.N.; Shvedunov, I.V.

2005-01-01

The upper level software of a three-level control system that supports several electron accelerators is described. This software operates in the Linux and RTLinux (Real Time Linux) environment. The object information model functions on the basis of a parametric description supported by the SQLite Data Base Management System. The Javascript sublanguage is used for script forming, and the Qt Designer application is used to construct the user interface [ru

Comparison the Serum STREM1 Levels Between Children with Upper and Lower UTI.

Science.gov (United States)

Ehsanipour, Fahime; Noorbakhsh, Samileh; Zarabi, Vida; Movahedi, Zahra; Rahimzadeh, Nahid

2017-01-01

Pyelonephritis is the most common and important infection among Iranian pediatric population. Differentiation between upper and lower Urinary Tract Infection (UTI) is often difficult based on clinical data. Therefore, definite diagnosis is helpful for choosing appropriate antibiotic and decision for hospital admission. The main purpose of this study was todetermine the diagnostic value of serum STREM-1 level in children suspicious to UTI and differentiation of upper UTI and lower UTI. This prospective cross sectional study (2010-2011) was performed to evaluate and compare the serum level of STREM- 1 (pg. /ml) in 36 diagnosed UTI patients (24 upper and 12 lower UTI) with 25 normal children (without UTI) in Rasoul Akram hospital, Tehran, Iran. The mean age of studied children was 3.64 years; 24 male and 37 female. Urinary analysis and urine culture were performed for all UTI cases and only the positive cultured cases with the same microorganism were enrolled in the study. Distinguishing the upper from lower UTI was done on the basis of clinical manifestation and laboratory tests and confirmed by Imaging studies (ultra sonography /or DMSA scan). Blood sampling was taken from all children and centrifuged .The level of STREM-1 (pg /ml) in all sera was determined by Enzyme immunoassay technique (Human TREM-1 immunoassay Sandwich test, Quantikine, R&D systems, Minneapolis; USA). Cut-off levels for STREM-1 were illustrated by ROC curve. The pUTI (427.72pg/ml) and controls (124.24 pg. /ml; P =0.000) ; with cutoff point 111.5 pg./ml ; it had 83.3% sensitivity; and 60 % specificity to distinguish UTI from control. Serum STREM -1 level had no significantly difference between the upper and lower UTI (500pg/ml vs. 283 pg. /ml, P value=0.1) with cutoff point 132 pg./ml it had 83.3% sensitivity ; and 60 % specificity to distinguish upper UTI from lower UTI. Our study demonstrates that even low amount of serum STREM-1 (111.5 pg./ml) has 83.3% sensitivity ; and 60 % specificity to

Groundwater levels for selected wells in Upper Kittitas County, Washington

Science.gov (United States)

Fasser, E.T.; Julich, R.J.

2011-01-01

Groundwater levels for selected wells in Upper Kittitas County, Washington, are presented on an interactive, web-based map to document the spatial distribution of groundwater levels in the study area measured during spring 2011. Groundwater-level data and well information were collected by the U.S. Geological Survey using standard techniques and are stored in the U.S. Geological Survey National Water Information System, Groundwater Site-Inventory database.

Using monomer vibrational wavefunctions to compute numerically exact (12D) rovibrational levels of water dimer

Science.gov (United States)

Wang, Xiao-Gang; Carrington, Tucker

2018-02-01

We compute numerically exact rovibrational levels of water dimer, with 12 vibrational coordinates, on the accurate CCpol-8sf ab initio flexible monomer potential energy surface [C. Leforestier et al., J. Chem. Phys. 137, 014305 (2012)]. It does not have a sum-of-products or multimode form and therefore quadrature in some form must be used. To do the calculation, it is necessary to use an efficient basis set and to develop computational tools, for evaluating the matrix-vector products required to calculate the spectrum, that obviate the need to store the potential on a 12D quadrature grid. The basis functions we use are products of monomer vibrational wavefunctions and standard rigid-monomer basis functions (which involve products of three Wigner functions). Potential matrix-vector products are evaluated using the F matrix idea previously used to compute rovibrational levels of 5-atom and 6-atom molecules. When the coupling between inter- and intra-monomer coordinates is weak, this crude adiabatic type basis is efficient (only a few monomer vibrational wavefunctions are necessary), although the calculation of matrix elements is straightforward. It is much easier to use than an adiabatic basis. The product structure of the basis is compatible with the product structure of the kinetic energy operator and this facilitates computation of matrix-vector products. Compared with the results obtained using a [6 + 6]D adiabatic approach, we find good agreement for the inter-molecular levels and larger differences for the intra-molecular water bend levels.

The effects of vibration-reducing gloves on finger vibration

Science.gov (United States)

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

2015-01-01

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

Adaptive vibration isolation system for diesel engine

Institute of Scientific and Technical Information of China (English)

YANG Tie-jun; ZHANG Xin-yu; XIAO You-hong; HUANG Jin-e; LIU Zhi-gang

2004-01-01

An active two-stage isolation mounting, on which servo-hydraulic system is used as the actuator (secondary vibration source) and a diesel engine is used as primary vibration source, has been built. The upper mass of the mounting is composed of a 495diesel and an electrical eddy current dynamometer. The lower mass is divided into four small masses to which servo-hydraulic actuator and rubber isolators are attached. According to the periodical characteristics of diesel vibration signals, a multi-point adaptive strategy based on adaptive comb filtered algorithm is applied to active multi-direction coupled vibrations control for the engine. The experimental results demonstrate that a good suppression in the effective range of phase compensation in secondary path (within 100Hz) at different operation conditions is achieved, and verify that this strategy is effective. The features of the active system, the development activities carried out on the system and experimental results are discussed in the paper.

Nearest neighbor spacing distributions of low-lying levels of vibrational nuclei

International Nuclear Information System (INIS)

Abul-Magd, A.Y.; Simbel, M.H.

1996-01-01

Energy-level statistics are considered for nuclei whose Hamiltonian is divided into intrinsic and collective-vibrational terms. The levels are described as a random superposition of independent sequences, each corresponding to a given number of phonons. The intrinsic motion is assumed chaotic. The level spacing distribution is found to be intermediate between the Wigner and Poisson distributions and similar in form to the spacing distribution of a system with classical phase space divided into separate regular and chaotic domains. We have obtained approximate expressions for the nearest neighbor spacing and cumulative spacing distribution valid when the level density is described by a constant-temperature formula and not involving additional free parameters. These expressions have been able to achieve good agreement with the experimental spacing distributions. copyright 1996 The American Physical Society

Upper Secondary and Vocational Level Teachers at Social Software

Science.gov (United States)

Valtonen, Teemu; Kontkanen, Sini; Dillon, Patrick; Kukkonen, Jari; Väisänen, Pertti

2014-01-01

This study focuses on upper secondary and vocational level teachers as users of social software i.e. what software they use during their leisure and work and for what purposes they use software in teaching. The study is theorised within a technological pedagogical content knowledge framework, the emphasis is especially on technological knowledge…

Contributions of the Higher Vibrational Levels of Nitric Oxide to the Radiative Cooling of the Thermosphere

Science.gov (United States)

Venkataramani, K.; Yonker, J. D.; Bailey, S. M.

2014-12-01

The 5.3μm emission from the vibrational levels of nitric oxide (NO) and the 15μm emission from CO2 are known to be the dominant sources of cooling in the thermosphere above 100 km. The 5.3μm emission is primarily produced by the radiative de-excitation of NO from its first vibrational level, which in turn is mainly populated by the collisions of NO with atomic oxygen. However, the reaction of atomic nitrogen (N(4S) and N(2D)) with O2 yields vibrationally excited NO with v>1, resulting in a radiative cascade which produces more than one 5.3μm photon per vibrationally excited NO molecule. This chemiluminescence is approximately 20% in magnitude of the emission produced by thermal collisions. These additional sources of the 5.3μm emission are introduced into a one dimensional photochemical model and the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) to assess their variability with latitude and solar activity, and to also understand their effect on the thermospheric energy budget. The results from the models are compared with data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment on-board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite, which has been making measurements of the infrared radiative response of the mesosphere and thermosphere to solar inputs since 2002.

Surface vibrational spectroscopy

International Nuclear Information System (INIS)

Erskine, J.L.

1984-01-01

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

Positron-attachment to small molecules: Vibrational enhancement of positron affinities with configuration interaction level of multi-component molecular orbital approach

Energy Technology Data Exchange (ETDEWEB)

Tachikawa, Masanori [Quantum Chemistry Division, Graduate School of NanoBioScience, Yokohama City University, 22-2 Seto, Kanazawa, Yokohama 236-0027 (Japan)

2015-12-31

To theoretically demonstrate the binding of a positron to small polarized molecules, we have calculated the vibrational averaged positron affinity (PA) values along the local vibrational contribution with the configuration interaction level of multi-component molecular orbital method. This method can take the electron-positron correlation contribution into account through single electronic - single positronic excitation configurations. The PA values are enhanced by including the local vibrational contribution from vertical PA values due to the anharmonicity of the potential.

Estimation of sound pressure levels of voiced speech from skin vibration of the neck

NARCIS (Netherlands)

Svec, JG; Titze, IR; Popolo, PS

How accurately can sound pressure levels (SPLs) of speech be estimated from skin vibration of the neck? Measurements using a small accelerometer were carried out in 27 subjects (10 males and 17 females) who read Rainbow and Marvin Williams passages in soft, comfortable, and loud voice, while skin

Physics Identity Development: A Snapshot of the Stages of Development of Upper-Level Physics Students

Science.gov (United States)

Irving, Paul W.; Sayre, Eleanor C.

2013-01-01

As part of a longitudinal study into identity development in upper-level physics students a phenomenographic research method is employed to assess the stages of identity development of a group of upper-level students. Three categories of description were discovered which indicate the three different stages of identity development for this group…

Postural stability effects of random vibration at the feet of construction workers in simulated elevation.

Science.gov (United States)

Simeonov, P; Hsiao, H; Powers, J; Ammons, D; Kau, T; Amendola, A

2011-07-01

The risk of falls from height on a construction site increases under conditions which degrade workers' postural control. At elevation, workers depend heavily on sensory information from their feet to maintain balance. The study tested two hypotheses: "sensory enhancement"--sub-sensory (undetectable) random mechanical vibrations at the plantar surface of the feet can improve worker's balance at elevation; and "sensory suppression"--supra-sensory (detectable) random mechanical vibrations can have a degrading effect on balance in the same experimental settings. Six young (age 20-35) and six aging (age 45-60) construction workers were tested while standing in standard and semi-tandem postures on instrumented gel insoles. The insoles applied sub- or supra-sensory levels of random mechanical vibrations to the feet. The tests were conducted in a surround-screen virtual reality system, which simulated a narrow plank at elevation on a construction site. Upper body kinematics was assessed with a motion-measurement system. Postural stability effects were evaluated by conventional and statistical mechanics sway measures, as well as trunk angular displacement parameters. Analysis of variance did not confirm the "sensory enhancement" hypothesis, but provided evidence for the "sensory suppression" hypothesis. The supra-sensory vibration had a destabilizing effect, which was considerably stronger in the semi-tandem posture and affected most of the sway variables. Sensory suppression associated with elevated vibration levels on a construction site may increase the danger of losing balance. Construction workers at elevation, e.g., on a beam or narrow plank might be at increased risk of fall if they can detect vibrations under their feet. To reduce the possibility of losing balance, mechanical vibration to supporting structures used as walking/working surfaces should be minimized when performing construction tasks at elevation. Published by Elsevier Ltd.

The influence of tropospheric static stability on upper-level frontogenesis

OpenAIRE

Saute, Marcel

2011-01-01

Upper-level frontogenesis in an inviscid, dry and adiabatic fluid forced by confluence is investigated by means of a two-dimensional semi-geostrophic model using the specific volume as an isentropic vertical coordinate. The initial conditions are specified given an analytical continuous potential vorticity field in the presence of a temperature contrast at the ground, the lower boundary condition requiring an appropriate treatment because the ground intersects the first levels of the model. T...

Triangle bracing system to reduce the vibration level of cooling tower – case study in PT Star Energy Geothermal (Wayang Windu) Ltd – Indonesia

OpenAIRE

Effendi Tri Bahtiar; Naresworo Nugroho; Dede Hermawan; Wilis Wirawan; Khuschandra

2018-01-01

Periodical control and measurement revealed that vibration level of motor and gearbox which was supported by Cooling Tower Unit 1 at PT Star Energy Geothermal (Wayang Windu) Ltd was significantly increasing since 2013. The vibration was not caused by machinery component failure, but induced by resonance of process flow. Decreasing stiffness of cooling tower structure was suspected causing the increasing vibration level. The physical, chemical, and mechanical properties of wood was deteriorate...

Multi-level Simulation of a Real Time Vibration Monitoring System Component

Science.gov (United States)

Robertson, Bryan A.; Wilkerson, Delisa

2005-01-01

This paper describes the development of a custom built Digital Signal Processing (DSP) printed circuit board designed to implement the Advanced Real Time Vibration Monitoring Subsystem proposed by Marshall Space Flight Center (MSFC) Transportation Directorate in 2000 for the Space Shuttle Main Engine Advanced Health Management System (AHMS). This Real Time Vibration Monitoring System (RTVMS) is being developed for ground use as part of the AHMS Health Management Computer-Integrated Rack Assembly (HMC-IRA). The HMC-IRA RTVMS design contains five DSPs which are highly interconnected through individual communication ports, shared memory, and a unique communication router that allows all the DSPs to receive digitized data fiom two multi-channel analog boards simultaneously. This paper will briefly cover the overall board design but will focus primarily on the state-of-the-art simulation environment within which this board was developed. This 16-layer board with over 1800 components and an additional mezzanine card has been an extremely challenging design. Utilization of a Mentor Graphics simulation environment provided the unique board and system level simulation capability to ascertain any timing or functional concerns before production. By combining VHDL, Synopsys Software and Hardware Models, and the Mentor Design Capture Environment, multiple simulations were developed to verify the RTVMS design. This multi-level simulation allowed the designers to achieve complete operability without error the first time the RTVMS printed circuit board was powered. The HMC-IRA design has completed all engineering and deliverable unit testing. P

Effects of different vibration exercises on bench press.

Science.gov (United States)

Marín, P J; Torres-Luque, G; Hernández-García, R; García-López, D; Garatachea, N

2011-10-01

This study was undertaken to analyze the effects of different vibration recovery strategies via feet or hands on the number of repetitions performed and on mean velocity, peak velocity and blood lactate concentration during consecutive bench-press sets. 9 elite judo athletes performed 3 sets of bench press at 60% of one-repetition maximum (1RM), leading to failure and allowing a 180 s rest period between sets. During the rest period, 1 of the 3 following procedures was performed: 150 s rest plus 30 s push-up vibration exercise (Push-up), 150 s rest plus 30 s squat vibration exercise (Squat) or 180 s only rest (Passive). Statistical analysis revealed that the Squat condition resulted in a significant increase in the number of repetitions achieved, in comparison with all other rest strategies. However, kinematic parameters and blood lactate concentration were not affected by vibration. These data suggest that a vibration stimulus applied to the feet, between sets, can result in positive improvements in upper body resistance exercise performance. Although the mechanisms are not fully understood, this positive effect of vibration could be due to an increased motor cortex excitability and voluntary drive. © Georg Thieme Verlag KG Stuttgart · New York.

Infrared radiation and inversion population of CO2 laser levels in Venusian and Martian atmospheres

Science.gov (United States)

Gordiyets, B. F.; Panchenko, V. Y.

1983-01-01

Formation mechanisms of nonequilibrium 10 micron CO2 molecule radiation and the possible existence of a natural laser effect in the upper atmospheres of Venus and Mars are theoretically studied. An analysis is made of the excitation process of CO2 molecule vibrational-band levels (with natural isotropic content) induced by direct solar radiation in bands 10.6, 9.4, 4.3, 2.7 and 2.0 microns. The model of partial vibrational-band temperatures was used in the case. The problem of IR radiation transfer in vibrational-rotational bands was solved in the radiation escape approximation.

Vibration in car repair work.

Science.gov (United States)

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

1987-03-01

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

Experiment studies of fuel rod vibration in coolant flow for substantiation of vibration stability of fuel rods with no fretting-wear

International Nuclear Information System (INIS)

Egorov, Yu. V.; Afanasiev, A. V.; Makarov, V. V.; Matvienko, I. V.

2013-01-01

For substantiation of vibration stability it is necessary to determine the ultimate permissible vibration levels which do not cause fretting, to compare them with the level of fuel rod vibration caused by coolant flow. Another approach is feasible if there is experience of successful operation of FA-prototypes. In this case in order to justify vibration stability it may be sufficient to demonstrate that the new element does not cause increased vibration of the fuel rod. It can be done by comparing the levels of hydro-dynamic fuel rod vibration and FA new designs. Program of vibration tests of TVS-2M model included studies of forced oscillations of 12 fuel rods in the coolant flow in the spans containing intensifiers, in the reference span without intensifiers, in the lower spans with assembled ADF and after its disassembly. The experimental results for TVS-2M show that in the spans with intensifier «Sector run» the level of movements is 6% higher on the average than in the span without intensifiers, in the spans with intensifier «Eddy» it is 2% higher. The level of fuel rod vibration movements in the spans with set ADF is 2 % higher on the average than without ADF. During the studies of TVS-KVADRAT fuel rod vibration, the following tasks were solved: determination of acceleration of the middle of fuel rod spans at vibration excited due to hydrodynamics; determination of influence of coolant thermal- hydraulic parameters (temperature, flowrate, dynamic pressure) on fuel rod vibration response; determination of influence of span lengths on the vibration level. Conclusions: 1) The vibration tests of the full-scale model of TVS-2M in the coolant flow showed that the new elements of TVS-2M design (intensifiers of heat exchange and ADF) are not the source of fuel rod increased vibration. Considering successful operation of similar fuel rod spans in the existing TVS-2M design, vibration stability of TVS-2M fuel rods with new elements is ensured on the mechanism of

Systematic vibration thermodynamic properties of bromine

Science.gov (United States)

Liu, G. Y.; Sun, W. G.; Liao, B. T.

2015-11-01

Based on the analysis of the maturity and finiteness of vibrational levels of bromine molecule in ground state and evaluating the effect on statistical computation, according to the elementary principles of quantum statistical theorem, using the full set of bromine molecular vibrational levels determined with algebra method, the statistical contribution for bromine systematical macroscopic thermodynamic properties is discussed. Thermodynamic state functions Helmholtz free energy, entropy and observable vibration heat capacity are calculated. The results show that the determination of full set of vibrational levels and maximum vibrational quantum number is the key in the correct statistical analysis of bromine systematical thermodynamic property. Algebra method results are clearly different from data of simple harmonic oscillator and the related algebra method results are no longer analytical but numerical and are superior to simple harmonic oscillator results. Compared with simple harmonic oscillator's heat capacities, the algebra method's heat capacities are more consistent with the experimental data in the given temperature range of 600-2100 K.

Collisional flow of vibrational energy into surrounding vibrational fields within S1 benzene

International Nuclear Information System (INIS)

Tang, K.Y.; Parmenter, C.S.

1983-01-01

Vapor phase fluorescence spectra are used to determine the absolute rate constants for the collisional transfer of vibrational energy from initial single vibronic levels of S 1 benzene into the surrounding S 1 vibronic field. 11 initial levels are probed with vibrational energies ranging to 2368 cm -1 where the level density is about 10 per cm -1 . CO, isopentane, and S 0 benzene are the collision partners. Benzene rate constants are three to four times gas kinetic for all levels, and electronic energy switching between the initial S 1 molecule and the S 0 collision partner probably makes important contributions. Isopentane efficiencies range from one to two times gas kinetic. Most of the transfer from low S 1 levels occurs with excitation of vibrational energy within isopentane. These V--V contributions decline to only about 10% for the high transfer. CO-induced transfer is by V-T,R processes for all levels. The CO efficiency rises from about 0.1 for low regions to about unity for levels above 1500 cm -1 . The CO efficiencies retain significant sensitivity to initial level identity even in the higher regions. Propensity rules derived from collisional mode-to-mode transfer among lower levels of S 1 benzene are used to calculate the relative CO efficiencies. The calculated efficiencies agree well enough with the data to suggest that it may be meaningful to model vibrational equilibration with the use of propensity rules. The rules suggest that only a small number of levels among the thousands surrounding a high initial level contribute significantly to the total relaxation cross section and that this number is rather independent of the level density

Whole-body vibration improves neuromuscular parameters and functional capacity in osteopenic postmenopausal women.

Science.gov (United States)

Dutra, Milena C; de Oliveira, Mônica L; Marin, Rosangela V; Kleine, Hellen C R; Silva, Orivaldo L; Lazaretti-Castro, Marise

2016-08-01

In this longitudinal, paired-control study, we developed special vibration platforms to evaluate the effects of low-intensity vibration on neuromuscular function and functional capacity in osteopenic postmenopausal women. Women in the platform group (PG; n = 62) stood still and barefoot on the platform for 20 minutes, 5 times a week for 12 months. Each platform vibrated with a frequency of 60 Hz, intensity of 0.6g, and amplitude of less than 1 mm. Women in the control group (CG; n = 60) were followed up and instructed not to modify their physical activity during the study. Every 3 months all volunteers were invited to a visit to check for any change in their lifestyle. Assessments were performed at baseline and at 12 months, and included isometric muscle strength in the hip flexors and back extensors, right handgrip strength, dynamic upper limb strength (arm curl test), upper trunk flexibility (reach test [RT]), mobility (timed up and go test), and static balance (unipedal stance test). Statistical analyses were performed using the intention-to-treat strategy. Both groups were similar for all variables at baseline. At the end of intervention, the PG was significantly better than CG in all parameters but in the RT. When compared with baseline, after 12 months of vibration the PG presented statistically significant improvements in isometric and dynamic muscle strength in the hip flexors (+36.7%), back extensors (+36.5%), handgrip strength (+4.4%), arm curl test (+22.8%), RT (+9.9%), unipedal stance test (+6.8%), and timed up and go test (-9.2%), whereas the CG showed no significant differences during the same period of time. As such, there were no side effects related to the study procedures during the 12 months of intervention. Low-intensity vibration improved balance, motility, and muscle strength in the upper and lower limbs in postmenopausal women.

Note: A component-level frequency tunable isolator for vibration-sensitive chips using SMA beams

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaoyong, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn; Yan, Xiaojun, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Collaborative Innovation Center of Advanced Aero-Engine, Beijing 100191 (China); National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics, Beijing 100191 (China); Beijing Key Laboratory of Aero-Engine Structure and Strength, Beijing 100191 (China); Ding, Xin; Wu, Di; Qi, Junlei; Wang, Ruixin; Lu, Siwei [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China)

2016-06-15

This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young’s modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz–97 Hz by applying different heating strategies. Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.

Note: A component-level frequency tunable isolator for vibration-sensitive chips using SMA beams

International Nuclear Information System (INIS)

Zhang, Xiaoyong; Yan, Xiaojun; Ding, Xin; Wu, Di; Qi, Junlei; Wang, Ruixin; Lu, Siwei

2016-01-01

This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young’s modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz–97 Hz by applying different heating strategies. Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.

Measuring Student Improvement in Lower- and Upper-Level University Climate Science Courses

Science.gov (United States)

Harris, S. E.; Taylor, S. V.; Schoonmaker, J. E.; Lane, E.; Francois, R. H.; Austin, P.

2011-12-01

What do university students know about climate? What do they learn in a climate course? On the second-to-last day of a course about global climate change, only 48% of our upper-level science students correctly answered a multiple-choice question about the greenhouse effect. The good news: improvement. Only 16% had answered correctly on the first day of class. The bad news: the learning opportunities we've provided appear to have missed more than half the class on a fundamental climate concept. To evaluate the effectiveness of instruction on student learning about climate, we have developed a prototype assessment tool, designed to be deployed as a low-stakes pre-post test. The items included were validated through student interviews to ensure that students interpret the wording and answer choices in the way we intend. This type of validated assessment, administered both at the beginning and end of term, with matched individuals, provides insight regarding the baseline knowledge with which our students enter a course, and the impact of that course on their learning. We administered test items to students in (1) an upper-level climate course for science majors and (2) a lower-level climate course open to all students. Some items were given to both groups, others to only one of the groups. Both courses use evidence-based pedagogy with active student engagement (clickers, small group activities, regular pre-class preparation). Our results with upper-level students show strong gains in student thinking (>70% of students who missed a question on the pre-test answered correctly on the post-test) about stock-and-flow (box model) problems, annual cycles in the Keeling curve, ice-albedo feedbacks, and isotopic fractionation. On different questions, lower-level students showed strong gains regarding albedo and blackbody emission spectra. Both groups show similar baseline knowledge and lower-than-expected gains on greenhouse effect fundamentals, and zero gain regarding the

Active Seismic Monitoring Using High-Power Moveable 40-TONS Vibration Sources in Altay-Sayn Region of Russia

Science.gov (United States)

Soloviev, V. M.; Seleznev, V. S.; Emanov, A. F.; Kashun, V. N.; Elagin, S. A.; Romanenko, I.; Shenmayer, A. E.; Serezhnikov, N.

2013-05-01

The paper presents data of operating vibroseismic observations using high-power stationary 100-tons and moveable 40-tons vibration sources, which have been carried out in Russia for 30 years. It is shown that investigations using high-power vibration sources open new possibilities for study stressedly-deformed condition of the Earth`s crust and the upper mantle and tectonic process in them. Special attention is given to developing operating seismic translucences of the Earth`s crust and the upper mantle using high-power 40-tons vibration sources. As a result of experimental researches there was proved high stability and repeatability of vibration effects. There were carried out long period experiments of many days with vibration source sessions of every two hours with the purpose of monitoring accuracy estimation. It was determined, that repeatability of vibroseismic effects (there was researched time difference of repeated sessions of P- and S-waves from crystal rocks surface) could be estimated as 10-3 - 10-4 sec. It is ten times less than revealed here annual variations of kinematic parameters according to regime vibroseismic observations. It is shown, that on hard high-speed grounds radiation spectrum becomes narrowband and is dislocated to high frequency; at the same time quantity of multiple high-frequency harmonic is growing. At radiation on soft sedimentary grounds (sand, clay) spectrum of vibration source in near zone is more broadband, correlograms are more compact. there Correspondence of wave fields from 40-tons vibration sources and explosions by reference waves from boundaries in he Earth`s crust and the upper mantle at record distance of 400 km was proved by many experiments in various regions of Russia; there was carried out the technique of high-power vibration sources grouping for increase of effectiveness of emanation and increase of record distance. According to results of long-term vibroseismic monitoring near Novosibirsk (1997-2012) there are

Enhancement of the vibration stability of a microdiffraction goniometer

International Nuclear Information System (INIS)

Lee, S. H.; Preissner, C.; Lai, B.; Cai, Z.; Shu, D.

2002-01-01

High-precision instrumentation, such as that for x-ray diffraction, electron microscopy, scanning probe microscopy, and other optical micropositioning systems, requires the stability that comes from vibration-isolated support structures. Structure-born vibrations impede the acquisition of accurate experimental data through such high-precision instruments. At the Advanced Photon Source, a multiaxis goniometer is installed in the 2-ID-D station for synchrotron microdiffraction investigations. However, ground vibration can excite the kinematic movements of the goniometer linkages, resulting in critically contaminated experimental data. In this paper, the vibration behavior of the goniometer has been considered. Experimental vibration measurements were conducted to define the present vibration levels and determine the threshold sensitivity of the equipment. In addition, experimental modal tests were conducted and used to guide an analytical finite element analysis. Both results were used for finding the best way to reduce the vibration levels and to develop a vibration damping/isolation structure for the 2-ID-D goniometer. The device that was designed and tested could be used to reduce local vibration levels for the vibration isolation of similar high-precision instruments

Comparison of Annoyance from Railway Noise and Railway Vibration.

Science.gov (United States)

Ögren, Mikael; Gidlöf-Gunnarsson, Anita; Smith, Michael; Gustavsson, Sara; Persson Waye, Kerstin

2017-07-19

The aim of this study is to compare vibration exposure to noise exposure from railway traffic in terms of equal annoyance, i.e., to determine when a certain noise level is equally annoying as a corresponding vibration velocity. Based on questionnaire data from the Train Vibration and Noise Effects (TVANE) research project from residential areas exposed to railway noise and vibration, the dose response relationship for annoyance was estimated. By comparing the relationships between exposure and annoyance for areas both with and without significant vibration exposure, the noise levels and vibration velocities that had an equal probability of causing annoyance was determined using logistic regression. The comparison gives a continuous mapping between vibration velocity in the ground and a corresponding noise level at the facade that are equally annoying. For equivalent noise level at the facade compared to maximum weighted vibration velocity in the ground the probability of annoyance is approximately 20% for 59 dB or 0.48 mm/s, and about 40% for 63 dB or 0.98 mm/s.

A study on the evaluation of vibration effect and the development of vibration reduction method for Wolsung unit 1 main steam piping

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyun; Kim, Yeon Whan [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Kim, Tae Ryong; Park, Jin Ho [Korea Atomic Energy Research Inst., Daeduk (Korea, Republic of)

1996-08-01

The main steam piping of nuclear power plant which runs between steam generator and high pressure turbine has been experienced to have a severe effect on the safe operation of the plant due to the vibration induced by the steam flowing inside the piping. The imposed cyclic loads by the vibration could result in the degradation of the related structures such as connection parts between main instruments, valves, pipe supports and building. The objective of the study is to reduce the vibration level of Wolsung nuclear power plant unit 1 main steam pipeline by analyzing vibration characteristics of the piping, identifying sources of the vibration and developing a vibration reduction method .The location of the maximum vibration is piping between the main steam header and steam chest .The stress level was found to be within the allowable limit .The main vibration frequency was found to be 4{approx}6 Hz which is the same as the natural frequency from model test .A vibration reduction method using pipe supports of energy absorbing type(WEAR)is selected .The measured vibration level after WEAR installation was reduced about 36{approx}77% in displacement unit (author). 36 refs., 188 figs.

Evaluation procedure for Service Level C and D upper shelf toughness criteria for Linde 80 weld material

International Nuclear Information System (INIS)

Gamble, R.M.

1993-09-01

Procedures have been defined to evaluate the upper shelf toughness criteria recently defined by ASME Section XI Subgroup on Evaluation Standards for ASME Service Level C and D conditions. These procedures and the ASME criteria were applied to assess the upper toughness requirements for axial Linde 80 welds in a typical PWR reactor pressure vessel beltline geometry. Because there is a wide spectrum of possible Level C and D events, the evaluation was performed for a bounding thermal transient and results were obtained to determine allowable pressure versus upper shelf energy. The allowable pressure for the bounding thermal transient was found to be above normal operating pressure for upper shelf energies equal to and greater than 40 ft-lb. Because a bounding thermal transient was used, the allowable pressures determined in this work should be minimum values. The results from this work provide a screening criterion to quickly identify limiting transients that may require more detailed analysis and an analysis procedure to assess compliance with ASME upper shelf energy criteria for Service Level C and D events. For events with significant thermal transients, such as those evaluated in this work, the transient pressure typically decreases rapidly from normal operating pressure to 1,500 psi or less before the maximum thermal K I , is reached. Comparing this pressure range with the allowable pressure versus upper shelf energy curves determined in this work indicates that the transient pressures are significantly less than the allowables computed for Level C and D events; consequently, Level A/B conditions will likely dictate the upper shelf requirements for most applications

Fostering Students' Preparation and Achievement in Upper Level Mathematics Courses

Science.gov (United States)

Celik, Mehmet; Shaqlaih, Ali

2017-01-01

This study describes an intervention to address both motivation, student engagement and preparation in upper-level mathematics courses. The effect of the intervention regarding students' achievements is investigated via students' opinions and data analysis from students' assessments. The results of this study show the featured intervention…

Local vibration inhibits H-reflex but does not compromise manual dexterity and does not increase tremor.

Science.gov (United States)

Budini, Francesco; Laudani, Luca; Bernardini, Sergio; Macaluso, Andrea

2017-10-01

The present work aimed at investigating the effects of local vibration on upper limb postural and kinetic tremor, on manual dexterity and on spinal reflex excitability. Previous studies have demonstrated a decrease in spinal reflex excitability and in force fluctuations in the lower limb but an increase in force fluctuation in the upper limbs. As hand steadiness is of vital importance in many daily-based tasks, and local vibration may also be applied in movement disorders, we decided to further explore this phenomenon. Ten healthy volunteers (26±3years) were tested for H reflex, postural and kinetic tremor and manual dexterity through a Purdue test. EMG was recorded from flexor carpi radialis (FCR) and extensor digitorum communis (EDC). Measurements were repeated at baseline, after a control period during which no vibration was delivered and after vibration. Intervention consisted in holding for two minutes a vibrating handle (frequency 75Hz, displacement∼7mm), control consisted in holding for two minutes the same handle powered off. Reflex excitability decreased after vibration whilst postural tremor and manual dexterity were not affected. Peak kinetic tremor frequency increased from baseline to control measurements (P=0.002). Co-activation EDC/FCR increased from control to vibration (P=0.021). These results show that two minutes local vibration lead to a decrease in spinal excitability, did not compromise manual dexterity and did not increase tremor; however, in contrast with expectations, tremor did not decrease. It is suggested that vibration activated several mechanisms with opposite effects, which resulted in a neutral outcome on postural and kinetic tremor. Copyright © 2017 Elsevier B.V. All rights reserved.

A Strategy for Magnifying Vibration in High-Energy Orbits of a Bistable Oscillator at Low Excitation Levels

International Nuclear Information System (INIS)

Wang Guang-Qing; Liao Wei-Hsin

2015-01-01

This work focuses on how to maintain a high-energy orbit motion of a bistable oscillator when subjected to a low level excitation. An elastic magnifier (EM) positioned between the base and the bistable oscillator is used to magnify the base vibration displacement to significantly enhance the output characteristics of the bistable oscillator. The dimensionless electromechanical equations of the bistable oscillator with an EM are derived, and the effects of the mass and stiffness ratios between the EM and the bistable oscillator on the output displacement are studied. It is shown that the jump phenomenon occurs at a lower excitation level with increasing the mass and stiffness ratios. With the comparison of the displacement trajectories and the phase portraits obtained from experiments, it is validated that the bistable oscillator with an EM can effectively oscillate in a high-energy orbit and can generate a superior output vibration at a low excitation level as compared with the bistable oscillator without an EM. (paper)

Smart Sensor for Analyzing Train Vibration in WCR Zone

Directory of Open Access Journals (Sweden)

Alka DUBEY

2009-09-01

Full Text Available In the present paper a smart vibration sensor is developed for railway electric engine WAP-7. Which is a self-sensation device equipped with recording and wireless communication interface. One programmed microcontroller 89C52 is used, which record vibration of trains with real time into memory. There is certain limit of vibrations, which is acceptable by track. Beyond this limit track can be damaged and may result major casualty. Smart sensor indicate the level of current vibration with its ideal value for prevention of excessive vibration it starts buzz ring. The work is highly applicable to the high speed trains. The high level vibration cause serious accidents due to the vibration.

Forced Vibrations of a Two-Layer Orthotropic Shell with an Incomplete Contact Between Layers

Science.gov (United States)

Ghulghazaryan, L. G.; Khachatryan, L. V.

2018-01-01

Forced vibrations of a two-layer orthotropic shell, with incomplete contact conditions between layers, when the upper face of the shell is free and the lower one is subjected to a dynamic action are considered. By an asymptotic method, the solution of the corresponding dynamic equations and correlations of a 3D problem of elasticity theory is obtained. The amplitudes of forced vibrations are determined, and resonance conditions are established.

Multiweek Cell Culture Project for Use in Upper-Level Biology Laboratories

Science.gov (United States)

Marion, Rebecca E.; Gardner, Grant E.; Parks, Lisa D.

2012-01-01

This article describes a laboratory protocol for a multiweek project piloted in a new upper-level biology laboratory (BIO 426) using cell culture techniques. Human embryonic kidney-293 cells were used, and several culture media and supplements were identified for students to design their own experiments. Treatments included amino acids, EGF,…

Ground test for vibration control demonstrator

Science.gov (United States)

Meyer, C.; Prodigue, J.; Broux, G.; Cantinaud, O.; Poussot-Vassal, C.

2016-09-01

In the objective of maximizing comfort in Falcon jets, Dassault Aviation is developing an innovative vibration control technology. Vibrations of the structure are measured at several locations and sent to a dedicated high performance vibration control computer. Control laws are implemented in this computer to analyse the vibrations in real time, and then elaborate orders sent to the existing control surfaces to counteract vibrations. After detailing the technology principles, this paper focuses on the vibration control ground demonstration that was performed by Dassault Aviation in May 2015 on Falcon 7X business jet. The goal of this test was to attenuate vibrations resulting from fixed forced excitation delivered by shakers. The ground test demonstrated the capability to implement an efficient closed-loop vibration control with a significant vibration level reduction and validated the vibration control law design methodology. This successful ground test was a prerequisite before the flight test demonstration that is now being prepared. This study has been partly supported by the JTI CleanSky SFWA-ITD.

Temporal Variability of Upper-level Winds at the Eastern Range, Western Range and Wallops Flight Facility

Science.gov (United States)

Decker, Ryan; Barbre, Robert E.

2014-01-01

Space launch vehicles incorporate upper-level wind profiles to determine wind effects on the vehicle and for a commit to launch decision. These assessments incorporate wind profiles measured hours prior to launch and may not represent the actual wind the vehicle will fly through. Uncertainty in the upper-level winds over the time period between the assessment and launch can be mitigated by a statistical analysis of wind change over time periods of interest using historical data from the launch range. Five sets of temporal wind pairs at various times (.75, 1.5, 2, 3 and 4-hrs) at the Eastern Range, Western Range and Wallops Flight Facility were developed for use in upper-level wind assessments. Database development procedures as well as statistical analysis of temporal wind variability at each launch range will be presented.

Upper Limb Muscle and Brain Activity in Light Assembly Task on Different Load Levels

Science.gov (United States)

Zadry, Hilma Raimona; Dawal, Siti Zawiah Md.; Taha, Zahari

2010-10-01

A study was conducted to investigate the effect of load on upper limb muscles and brain activities in light assembly task. The task was conducted at two levels of load (Low and high). Surface electromyography (EMG) was used to measure upper limb muscle activities of twenty subjects. Electroencephalography (EEG) was simultaneously recorded with EMG to record brain activities from Fz, Pz, O1 and O2 channels. The EMG Mean Power Frequency (MPF) of the right brachioradialis and the left upper trapezius activities were higher on the high-load task compared to low-load task. The EMG MPF values also decrease as time increases, that reflects muscle fatigue. Mean power of the EEG alpha bands for the Fz-Pz channels were found to be higher on the high-load task compared to low-load task, while for the O1-O2 channels, they were higher on the low-load task than on the high-load task. These results indicated that the load levels effect the upper limb muscle and brain activities. The high-load task will increase muscle activities on the right brachioradialis and the left upper tapezius muscles, and will increase the awareness and motivation of the subjects. Whilst the low-load task can generate drowsiness earlier. It signified that the longer the time and the more heavy of the task, the subjects will be more fatigue physically and mentally.

Heavy Rydberg behaviour in high vibrational levels of some ion-pair states of the halogens and inter-halogens

International Nuclear Information System (INIS)

Donovan, Robert J.; Lawley, Kenneth P.; Ridley, Trevor

2015-01-01

We report the identification of heavy Rydberg resonances in the ion-pair spectra of I 2 , Cl 2 , ICl, and IBr. Extensive vibrational progressions are analysed in terms of the energy dependence of the quantum defect δ(E b ) rather than as Dunham expansions. This is shown to define the heavy Rydberg region, providing a more revealing fit to the data with fewer coefficients and leads just as easily to numbering data sets separated by gaps in the observed vibrational progressions. Interaction of heavy Rydberg states with electronic Rydberg states at avoided crossings on the inner wall of the ion-pair potential is shown to produce distinctive changes in the energy dependence of δ(E b ), with weak and strong interactions readily distinguished. Heavy Rydberg behaviour is found to extend well below near-dissociation states, down to vibrational levels ∼18 000-20 000 cm −1 below dissociation. The rapid semi-classical calculation of δ(E b ) for heavy Rydberg states is emphasised and shows their absolute magnitude to be essentially the volume of phase space excluded from the vibrational motion by avoiding core-core penetration of the ions

Vibrations on board and health effects

DEFF Research Database (Denmark)

Jensen, Anker; Jepsen, Jørgen Riis

2014-01-01

There is only limited knowledge of the exposure to vibrations of ships’ crews and their risk of vibration-induced health effects. Exposure to hand-arm vibrations from the use of vibrating tools at sea does not differ from that in the land-based trades. However, in contrast to most other work places...... of the health consequences of whole body vibrations in land-transportation, such exposure at sea may affect ships’ passengers and crews. While the relation of back disorders to high levels of whole body vibration has been demonstrated among e.g. tractor drivers, there are no reported epidemiological evidence...... for such relation among seafarers except for fishermen, who, however, are also exposed to additional recognised physical risk factors at work. The assessment and reduction of vibrations by naval architects relates to technical implications of this impact for the ships’ construction, but has limited value...

Focal Muscle Vibration and Physical Exercise in Postmastectomy Recovery: An Explorative Study

Directory of Open Access Journals (Sweden)

Claudia Celletti

2017-01-01

Full Text Available Background. Physical activity initiation and maintenance are particular challenges in the postmastectomy recovery and in particular Dragon Boat racing seems to be a useful sport activity. The aim of this study was to evaluate the role of focal muscle vibration as a proprioceptive input to improve upper limb functioning in a group of “paddlers” patients. Methods. A group of paddlers has been evaluated before vibratory treatment (T0, immediately after therapy (T1, after one week (T2, and after one month (T3 with DASH questionnaire, Body Image Scale, McGill pain questionnaire, Constant Scale, and Short Form 36 questionnaire. Results. Fourteen patients showed a significant reduction in disability score (p=0,001 using DASH scale, an improvement of upper limb function (p=0,001 using the Constant scale, and a reduction of pain (p=0,007 at the McGill pain questionnaire. The Mental Composite Score of the Short Form 36 questionnaire showed significant results (p=0,04 while no significant results had been found regarding the physical mental score (p=0,08. Conclusion. Focal muscle vibration may be a useful treatment in a postmastectomy recovery of upper limb functionality.

Predicting Statistical Distributions of Footbridge Vibrations

DEFF Research Database (Denmark)

Pedersen, Lars; Frier, Christian

2009-01-01

The paper considers vibration response of footbridges to pedestrian loading. Employing Newmark and Monte Carlo simulation methods, a statistical distribution of bridge vibration levels is calculated modelling walking parameters such as step frequency and stride length as random variables...

Influence of bearing pre-load coefficient on shaft vibration and pad temperature in a hydroturbine generator unit. A case study

Energy Technology Data Exchange (ETDEWEB)

Feng Fuzhou; Chu Fulei; Guo Dan; Lu Wenxiu [Tsinghua Univ., Beijing, BJ (China). Dept. of Precision Instruments

2001-07-01

From data collected by an online condition monitoring and fault diagnosis system, a higher pad temperature at the upper guide bearing in a pumped storage power generator unit installed in Guangdong province(GPSPS), China, was found. And also a relatively intensive shaft vibration occurred at the lower guide bearing. By calculating the Reynolds equation and viscosity-temperature equation of the lubricant, a curve between the pre-load coefficient and the increment of pad temperature is obtained, which shows that the larger, the pre-load coefficient, the bigger, the increment of pad temperature. For a practical unit in GPSPS, by employing Transfer matrix method and Wilson-{theta} method to analyze shaft vibration at different pre-load coefficients of the whole bearing or ''pad pair'' bearings, the results show that the larger the pre-load coefficient is, the smaller the vibration amplitude is, the shorter the time for vibration to become steady is. And an uneven pre-load coefficient of the ''pad pair'' bearings will cause shaft orbit from a circle to an ellipse whose long axes is at the direction of the ''pad pair'' with the lowest pre-load coefficient. Finally, reasons of higher pad temperature of the upper guide bearing and larger shaft vibration at the lower guide bearing are due to the inconsistent relation of bearing assembling clearance or pre-load coefficient of the upper and lower guide bearing, and also due to the too small, uneven pre-load coefficient of ''pad pair'' bearings. After a scheme for adjusting the bearing clearance is given, data measured show that the analysis and simulation methods are correct and the adjustment scheme to the assembling clearance of the upper and lower guide bearings is feasible and can be used to guide the field maintenance conveniently. (orig.)

Enhanced vibration diagnostics using vibration signature analysis

International Nuclear Information System (INIS)

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

2001-01-01

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

Stabilization of axisymmetric liquid bridges through vibration-induced pressure fields.

Science.gov (United States)

Haynes, M; Vega, E J; Herrada, M A; Benilov, E S; Montanero, J M

2018-03-01

Previous theoretical studies have indicated that liquid bridges close to the Plateau-Rayleigh instability limit can be stabilized when the upper supporting disk vibrates at a very high frequency and with a very small amplitude. The major effect of the vibration-induced pressure field is to straighten the liquid bridge free surface to compensate for the deformation caused by gravity. As a consequence, the apparent Bond number decreases and the maximum liquid bridge length increases. In this paper, we show experimentally that this procedure can be used to stabilize millimeter liquid bridges in air under normal gravity conditions. The breakup of vibrated liquid bridges is examined experimentally and compared with that produced in absence of vibration. In addition, we analyze numerically the dynamics of axisymmetric liquid bridges far from the Plateau-Rayleigh instability limit by solving the Navier-Stokes equations. We calculate the eigenfrequencies characterizing the linear oscillation modes of vibrated liquid bridges, and determine their stability limits. The breakup process of a vibrated liquid bridge at that stability limit is simulated too. We find qualitative agreement between the numerical predictions for both the stability limits and the breakup process and their experimental counterparts. Finally, we show the applicability of our technique to control the amount of liquid transferred between two solid surfaces. Copyright © 2017 Elsevier Inc. All rights reserved.

Critical phenomena in quasi-two-dimensional vibrated granular systems.

Science.gov (United States)

Guzmán, Marcelo; Soto, Rodrigo

2018-01-01

The critical phenomena associated to the liquid-to-solid transition of quasi-two-dimensional vibrated granular systems is studied using molecular dynamics simulations of the inelastic hard sphere model. The critical properties are associated to the fourfold bond-orientational order parameter χ_{4}, which measures the level of square crystallization of the system. Previous experimental results have shown that the transition of χ_{4}, when varying the vibration amplitude, can be either discontinuous or continuous, for two different values of the height of the box. Exploring the amplitude-height phase space, a transition line is found, which can be either discontinuous or continuous, merging at a tricritical point and the continuous branch ends in an upper critical point. In the continuous transition branch, the critical properties are studied. The exponent associated to the amplitude of the order parameter is β=1/2, for various system sizes, in complete agreement with the experimental results. However, the fluctuations of χ_{4} do not show any critical behavior, probably due to crossover effects by the close presence of the tricritical point. Finally, in quasi-one-dimensional systems, the transition is only discontinuous, limited by one critical point, indicating that two is the lower dimension for having a tricritical point.

Analysis of the effect of vibrations on the bentonite buffer in the canister hole

International Nuclear Information System (INIS)

Jonsson, Martin; Hakami, Hossein; Ekneligoda, Thushan

2009-09-01

During the construction of a final repository for spent nuclear fuel in crystalline rock, blasting activities in certain deposition tunnels will occur at the same time as the deposition of canisters containing the waste is going on in another adjacent access tunnel. In fact, the deposition consists of several stages after the drilling of the deposition hole. The most vulnerable stage from a vibration point of view is when the bentonite buffer is placed in the deposition hole but the canister has not been placed yet. During this stage, a hollow column of bentonite blocks remains free to vibrate inside the deposition hole. The goal of this study was to investigate the displacement of the bentonite blocks when exposed to the highest vibration level that can be expected during the drill and blast operations. In order to investigate this, a three dimensional model in 3DEC, capable of capturing the dynamic behaviour of the bentonite buffer was set up. To define the vibration levels, which serve as input data for the 3DEC model, an extensive analysis of the recorded vibrations from the TASQ - tunnel was carried out. For this purpose, an upper expected vibration limit was defined. This was done outgoing from the fact that the planned charging for the construction of the geological repository will lie in the interval 2 to 4 kg. Furthermore, at the first stage for this study, it was decided that the vibration should be conservatively evaluated for 30 m distance. Using these data, it was concluded that the maximum vibration level that can be expected will be approximately 60 mm/s. After simplifying the vibration signal, a sinusoidal wave with the amplitude 60 mm/s was applied at the bottom of the column and it was assumed that the vibrations only affect the bentonite buffer in one direction (horizontal direction). From this simulation, it was concluded that hardly any displacements occurred. However, when applying the same sinusoidal wave both in the horizontal and the

Somatosensory Nerve Function, Measured by Vibration Thresholds in Asymptomatic Tennis Players: A Pilot Study

Directory of Open Access Journals (Sweden)

Sarah Harrisson

2015-06-01

Full Text Available Tennis players are vulnerable to injury in their upper limbs due to the repetitive exposure to racket vibrations and torsional forces during play, leading to musculoskeletal adaptations in the dominant arm including some evidence of changes in nerve function (Colak et al., 2004. Vibration is a sensitive technique for diagnosing mild pathology in clinically asymptomatic participant groups. It has been used in participants with various musculoskeletal disorders (Laursen et al., 2006 (Tucker et al., 2007 showing widespread and bilateral increases in vibration threshold. Tests of somatosensory function by vibration will be abnormal prior to changes in nerve conduction velocity. Thus vibration testing in a sub-clinical group of participants may a more sensitive measure of nerve function compared to nerve conduction by electrodiagnostic testing. The aim of this pilot study was to conduct an exploratory investigation to establish whether tennis players have a reduction in their somatosensory nerve function compared to non- tennis playing controls. It also set out to compare the somatosensory nerve function of the dominant compared to the non-dominant upper limb in tennis players. Healthy tennis players (males, n = 8, females, n = 2, mean age 22 years and control non- tennis playing volunteers (males, n = 6, females, n = 4, mean age 22 years were recruited on an opportunistic basis from a tennis centre in London UK. Participants were excluded if they had any history of neurological impairment, serious injury or fracture or any arthritic condition affecting the upper limbs, cervical or thoracic spine. Control participants were excluded if it was deemed that they played a sport where there was exposure to repetitive use of the upper body. Ethical approval was obtained from the University College London Ethics Committee and all participants gave written informed consent. A preliminary clinical examination was carried out on all participants followed by

Predicting footbridge vibrations using a probability-based approach

DEFF Research Database (Denmark)

Pedersen, Lars; Frier, Christian

2017-01-01

Vibrations in footbridges may be problematic as excessive vibrations may occur as a result of actions of pedestrians. Design-stage predictions of levels of footbridge vibration to the action of a pedestrian are useful and have been employed for many years based on a deterministic approach to mode...

Laser-induced vibration of a thin soap film.

Science.gov (United States)

Emile, Olivier; Emile, Janine

2014-09-21

We report on the vibration of a thin soap film based on the optical radiation pressure force. The modulated low power laser induces a counter gravity flow in a vertical free-standing draining film. The thickness of the soap film is then higher in the upper region than in the lower region of the film. Moreover, the lifetime of the film is dramatically increased by a factor of 2. Since the laser beam only acts mechanically on the film interfaces, such a film can be employed in an optofluidic diaphragm pump, the interfaces behaving like a vibrating membrane and the liquid in-between being the fluid to be pumped. Such a pump could then be used in delicate micro-equipment, in chips where temperature variations are detrimental and even in biological systems.

Control of pipe vibrations; Schwingungsminderung bei Rohrleitungen

Energy Technology Data Exchange (ETDEWEB)

Sinambari, G.R. [FH Bingen, Fachrichtung Umweltschutz, und IBS Ingenieurbuero fuer Schall- und Schwingungstechnik GmbH, Frankenthal (Germany); Thorn, U. [IBS Ingenieurbuero fuer Schall- und Schwingungstechnik GmbH, Frankenthal (Germany)

2005-06-01

Following commissioning of a new vacuum system for the refinery of MiRO Mineraloelraffinerie Oberrhein GmbH and Co. KG, vibrations occurred in the furnace exhaust pipes. As these had to be regarded as critical for the fatigue strength of the pipes, the pipes' vibration response in the critical frequency range was investigated immediately by means of a vibration analysis, and appropriate measures for vibration control were elaborated. All investigations, and the installation of the hydraulic vibration dampers, took place with the system operating. The effectiveness of the measures taken was checked by means of measurements following installation. The measures succeeded in attenuating the vibrations to a level at which, empirically, damage need no longer be expected. This paper illustrates the procedure for developing the vibration control measures and the essential results of the investigations. (orig.)

Level of Agreement Between Forearm and Upper Arm Blood Pressure Measurements in Patients With Large Arm Circumference.

Science.gov (United States)

Watson, Sheri; Aguas, Marita; Colegrove, Pat; Foisy, Nancy; Jondahl, Bonnie; Anastas, Zoe

2017-02-01

The purpose of the study was to determine if forearm blood pressures (BPs) measured in three different locations agree with the recommended upper arm location for noninvasive BP measurement. A method-comparison design was used. In a convenience sample of postanesthesia care unit patients with large upper arm circumference, BP's were obtained in three different forearm locations (lower forearm, middle forearm, and upper forearm) and compared to upper arm BP using an automated BP measuring device. The level of agreement (bias ± precision) between each forearm location and the upper arm BP was calculated using standard formulas. Acceptable levels of agreement based on expert opinion were set a priori at bias and precision values of less than ±5 mm Hg (bias) and ±8 mm Hg (precision). Forty-eight postanesthesia patients participated in the study. Bias and precision values were found to exceed the acceptable level of agreement for all but one of the systolic and diastolic BP comparisons in the three forearm BP locations. Fifty-six percent of all patients studied had one or more BP difference of at least 10 mm Hg in each of the three forearm locations, with 10% having one or more differences of at least 20 mm Hg. The differences in forearm BP measurements observed in this study indicate that the clinical practice of using a forearm BP with a regular-sized BP cuff in place of a larger sized BP cuff placed on the upper arm in postanesthesia care unit patients with large arm circumferences is inappropriate. The BPs obtained at the forearm location are not equivalent to the BPs obtained at the upper arm location. Copyright © 2015 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.

Southern Dobrogea coastal potable water sources and Upper Quaternary Black Sea level changes

Science.gov (United States)

Caraivan, Glicherie; Stefanescu, Diana

2013-04-01

Southern Dobrogea is a typical geologic platform unit, placed in the south-eastern part of Romania, with a Pre-Cambrian crystalline basement and a Paleozoic - Quaternary sedimentary cover. It is bordered to the north by the Capidava - Ovidiu fault and by the Black Sea to the east. A regional WNW - ESE and NNE - SSW fault system divides the Southern Dobrogea structure in several tectonic blocks. Four drinking water sources have been identified: surface water, phreatic water, medium depth Sarmatian aquifer, and deep Upper Jurassic - Lower Cretaceous aquifer. Surface water sources are represented by several springs emerged from the base of the loess cliff, and a few small rivers, barred by coastal beaches. The phreatic aquifer develops at the base of the loess deposits, on the impervious red clay, overlapping the Sarmatian limestones. The medium depth aquifer is located in the altered and karstified Sarmatian limestones, and discharges into the Black Sea. The Sarmatian aquifer is unconfined where covered by silty loess deposits, and locally confined, where capped by clayey loess deposits. The aquifer is supplied from the Pre-Balkan Plateau. The Deep Upper Jurassic - Lower Cretaceous aquifer, located in the limestone and dolomite deposits, is generally confined and affected by the regional WNW - ESE and NNE - SSW fault system. In the south-eastern Dobrogea, the deep aquifer complex is separated from the Sarmatian aquifer by a Senonian aquitard (chalk and marls). The natural boundary of the Upper Jurassic - Lower Cretaceous aquifer is the Capidava - Ovidiu Fault. The piezometric heads show that the Upper Jurassic - Lower Cretaceous aquifer is supplied from the Bulgarian territory, where the Upper Jurassic deposits crop out. The aquifer discharges into the Black Sea to the east and into Lake Siutghiol to the northeast. The cyclic Upper Quaternary climate changes induced drastic remodeling of the Black Sea level and the corresponding shorelines. During the Last Glacial

Incentivizing Advanced Mathematics Study at Upper Secondary Level: The Case of Bonus Points in Ireland

Science.gov (United States)

Treacy, Páraic Thomas

2018-01-01

Secondary level mathematics education in Ireland has recently experienced a period of significant change with the introduction of new curricula and the addition of an incentive to study upper secondary mathematics at the most advanced level (Higher Level). This incentive, typically referred to as 'bonus points', appears to have aided a significant…

Daily exposure to hand arm vibration by different electric olive beaters

Directory of Open Access Journals (Sweden)

Angela Calvo

2014-11-01

Full Text Available The electric hand held olive harvesters have a low weight (about 2 kg and cause the fruit pick up by means of impacts produced by their vibrational tools: for this reason they transmit elevated vibration doses to the operator’s hand arm system during the work. In this paper electric beaters of different manufacturers and different models were considered, to analyse their vibrational behaviour in field, during the olive harvesting campaign in a site located in Northern Italy. One operator did the tests, to avoid the operator’s uncertainty on the obtained results. All the five examined beaters gave high acceleration values (in a range from 10 to 26 ms–2, but the most restricting data were the daily vibration exposures, calculated considering the real working duration time acquired in field, almost ranged between 10 and 18 ms–2. Also the operator posture during the work (with the arms over the shoulders may set health problems, related to upper limb disorders, other than the already known musculoskeletal, nervous and vascular pathologies.

Synoptic climatology of the long-distance dispersal of white pine blister rust I. Development of an upper level synoptic classification

Science.gov (United States)

K. L. Frank; L. S. Kalkstein; B. W. Geils; H. W. Thistle

2008-01-01

This study developed a methodology to temporally classify large scale, upper level atmospheric conditions over North America, utilizing a newly-developed upper level synoptic classification (ULSC). Four meteorological variables: geopotential height, specific humidity, and u- and v-wind components, at the 500 hPa level over North America were obtained from the NCEP/NCAR...

Colorado Upper-Division Electrostatics Diagnostic: A Conceptual Assessment for the Junior Level

Science.gov (United States)

Chasteen, Stephanie V.; Pepper, Rachel E.; Caballero, Marcos D.; Pollock, Steven J.; Perkins, Katherine K.

2012-01-01

As part of an effort to systematically improve our junior-level E&M I course, we have developed a tool to assess student conceptual learning of electrostatics at the upper division. Together with a group of physics faculty, we established a list of learning goals for the course that, with results from student observations and interviews,…

Two improvements on numerical simulation of 2-DOF vortex-induced vibration with low mass ratio

Science.gov (United States)

Kang, Zhuang; Ni, Wen-chi; Zhang, Xu; Sun, Li-ping

2017-12-01

Till now, there have been lots of researches on numerical simulation of vortex-induced vibration. Acceptable results have been obtained for fixed cylinders with low Reynolds number. However, for responses of 2-DOF vortex-induced vibration with low mass ratio, the accuracy is not satisfactory, especially for the maximum amplitudes. In Jauvtis and Williamson's work, the maximum amplitude of the cylinder with low mass ratio m*=2.6 can reach as large as 1.5 D to be called as the "super-upper branch", but from current literatures, few simulation results can achieve such value, even fail to capture the upper branch. Besides, it is found that the amplitude decays too fast in the lower branch with the RANS-based turbulence model. The reason is likely to be the defects of the turbulence model itself in the prediction of unsteady separated flows as well as the unreasonable setting of the numerical simulation parameters. Aiming at above issues, a modified turbulence model is proposed in this paper, and the effect of the acceleration of flow field on the response of vortex-induced vibration is studied based on OpenFOAM. By analyzing the responses of amplitude, phase and trajectory, frequency and vortex mode, it is proved that the vortex-induced vibration can be predicted accurately with the modified turbulence model under appropriate flow field acceleration.

Influence of light-induced conical intersection on the photodissociation dynamics of D2(+) starting from individual vibrational levels.

Science.gov (United States)

Halász, Gábor J; Csehi, András; Vibók, Ágnes; Cederbaum, Lorenz S

2014-12-26

Previous works have shown that dressing of diatomic molecules by standing or by running laser waves gives rise to the appearance of so-called light-induced conical intersections (LICIs). Because of the strong nonadiabatic couplings, the existence of such LICIs may significantly change the dynamical properties of a molecular system. In our former paper (J. Phys. Chem. A 2013, 117, 8528), the photodissociation dynamics of the D(2)(+) molecule were studied in the LICI framework starting the initial vibrational nuclear wave packet from the superposition of all the vibrational states initially produced by ionizing D(2). The present work complements our previous investigation by letting the initial nuclear wave packets start from different individual vibrational levels of D(2)(+), in particular, above the energy of the LICI. The kinetic energy release spectra, the total dissociation probabilities, and the angular distributions of the photofragments are calculated and discussed. An interesting phenomenon has been found in the spectra of the photofragments. Applying the light-induced adiabatic picture supported by LICI, explanations are given for the unexpected structure of the spectra.

Spectroscopy and reactions of vibrationally excited transient molecules

Energy Technology Data Exchange (ETDEWEB)

Dai, H.L. [Univ. of Pennsylvania, Philadelphia (United States)

1993-12-01

Spectroscopy, energy transfer and reactions of vibrationally excited transient molecules are studied through a combination of laser-based excitation techniques and efficient detection of emission from the energized molecules with frequency and time resolution. Specifically, a Time-resolved Fourier Transform Emission Spectroscopy technique has been developed for detecting dispersed laser-induced fluorescence in the IR, visible and UV regions. The structure and spectroscopy of the excited vibrational levels in the electronic ground state, as well as energy relaxation and reactions induced by specific vibronic excitations of a transient molecule can be characterized from time-resolved dispersed fluorescence in the visible and UV region. IR emissions from highly vibrational excited levels, on the other hand, reveal the pathways and rates of collision induced vibrational energy transfer.

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.

Exposure to whole-body vibration and mechanical shock: a field study of quad bike use in agriculture.

Science.gov (United States)

Milosavljevic, Stephan; McBride, David I; Bagheri, Nasser; Vasiljev, Radivoj M; Mani, Ramakrishnan; Carman, Allan B; Rehn, Borje

2011-04-01

The purpose of this study was to determine exposure to whole-body vibration (WBV) and mechanical shock in rural workers who use quad bikes and to explore how personal, physical, and workplace characteristics influence exposure. A seat pad mounted triaxial accelerometer and data logger recorded full workday vibration and shock data from 130 New Zealand rural workers. Personal, physical, and workplace characteristics were gathered using a modified version of the Whole Body Vibration Health Surveillance Questionnaire. WBVs and mechanical shocks were analysed in accordance with the International Standardization for Organization (ISO 2631-1 and ISO 2631-5) standards and are presented as vibration dose value (VDV) and mechanical shock (S(ed)) exposures. VDV(Z) consistently exceeded European Union (Guide to good practice on whole body vibration. Directive 2002/44/EC on minimum health and safety, European Commission Directorate General Employment, Social Affairs and Equal Opportunities. 2006) guideline exposure action thresholds with some workers exceeding exposure limit thresholds. Exposure to mechanical shock was also evident. Increasing age had the strongest (negative) association with vibration and shock exposure with body mass index (BMI) having a similar but weaker effect. Age, daily driving duration, dairy farming, and use of two rear shock absorbers created the strongest multivariate model explaining 33% of variance in VDV(Z). Only age and dairy farming combined to explain 17% of the variance for daily mechanical shock. Twelve-month prevalence for low back pain was highest at 57.7% and lowest for upper back pain (13.8%). Personal (age and BMI), physical (shock absorbers and velocity), and workplace characteristics (driving duration and dairy farming) suggest that a mix of engineered workplace and behavioural interventions is required to reduce this level of exposure to vibration and shock.

Direct observation of vibrational energy dispersal via methyl torsions.

Science.gov (United States)

Gardner, Adrian M; Tuttle, William D; Whalley, Laura E; Wright, Timothy G

2018-02-28

Explicit evidence for the role of methyl rotor levels in promoting energy dispersal is reported. A set of coupled zero-order vibration/vibration-torsion (vibtor) levels in the S 1 state of para -fluorotoluene ( p FT) are investigated. Two-dimensional laser-induced fluorescence (2D-LIF) and two-dimensional zero-kinetic-energy (2D-ZEKE) spectra are reported, and the assignment of the main features in both sets of spectra reveals that the methyl torsion is instrumental in providing a route for coupling between vibrational levels of different symmetry classes. We find that there is very localized, and selective, dissipation of energy via doorway states, and that, in addition to an increase in the density of states, a critical role of the methyl group is a relaxation of symmetry constraints compared to direct vibrational coupling.

Architecture-independent power bound for vibration energy harvesters

International Nuclear Information System (INIS)

Halvorsen, E; Le, C P; Mitcheson, P D; Yeatman, E M

2013-01-01

The maximum output power of energy harvesters driven by harmonic vibrations is well known for a range of specific harvester architectures. An architecture-independent bound based on the mechanical input-power also exists and gives a strict limit on achievable power with one mechanical degree of freedom, but is a least upper bound only for lossless devices. We report a new theoretical bound on the output power of vibration energy harvesters that includes parasitic, linear mechanical damping while still being architecture independent. This bound greatly improves the previous bound at moderate force amplitudes and is compared to the performance of established harvester architectures which are shown to agree with it in limiting cases. The bound is a hard limit on achievable power with one mechanical degree of freedom and can not be circumvented by transducer or power-electronic-interface design

Fundamental Vibration of Molecular Hydrogen

Science.gov (United States)

Dickenson, G. D.; Niu, M. L.; Salumbides, E. J.; Komasa, J.; Eikema, K. S. E.; Pachucki, K.; Ubachs, W.

2013-05-01

The fundamental ground tone vibration of H2, HD, and D2 is determined to an accuracy of 2×10-4cm-1 from Doppler-free laser spectroscopy in the collisionless environment of a molecular beam. This rotationless vibrational splitting is derived from the combination difference between electronic excitation from the X1Σg+, v=0, and v=1 levels to a common EF1Σg+, v=0 level. Agreement within 1σ between the experimental result and a full ab initio calculation provides a stringent test of quantum electrodynamics in a chemically bound system.

Examining portfolio-based assessment in an upper-level biology course

Science.gov (United States)

Ziegler, Brittany Ann

Historically, students have been viewed as empty vessels and passive participants in the learning process but students actually are active forming their own conceptions. One way student learning is impacted is through assessment. Alternative assessment, which contrasts traditional assessment methods, takes into account how students learn by promoting engagement and construction of knowledge This dissertation explores portfolio-based assessment, a method of alternative assessment, which requires students to compose a purposeful collection of work demonstrating their knowledge in an upper-level biology course. The research objectives include characterizing and contributing to the understanding of portfolio-based assessment in higher education, examining reflection and inquiry portfolio components, determining student knowledge of biological concepts, and investigating student integrative thinking through the transformation of reflections into concept webs One main finding includes the majority of reflections categorized as naive or novice in quality. There was no difference in quality of reflections among biological topic. There was a relatively equal amount of high and low cognitive level questions. Students' knowledge of biological concepts significantly increased from the beginning to end of the course. Student written reflections were transformed into concept webs to allow for examination of student integrative thinking. Concepts, relationships, and interconnections in concept webs showed variation but declined by the end of the semester This study is one of the first examining portfolio-based assessment in an upper-level biology course We do not contend that this method of assessment is the only way to promote student learning but portfolio-based assessment may be a tool that can transform science education but currently the role of portfolio-based assessment in science education remains unclear. Additional research needs to be conducted before we will fully

Local vibrations and lift performance of low Reynolds number airfoil

Directory of Open Access Journals (Sweden)

TariqAmin Khan

2017-06-01

Full Text Available The 2D incompressible Navier-Stokes equations are solved based on the finite volume method and dynamic mesh technique is used to carry out partial fluid structure interaction. The local flexible structure (hereinafter termed as flexible structure vibrates in a single mode located on the upper surface of the airfoil. The Influence of vibration frequency and amplitude are examined and the corresponding fluid flow characteristics are investigated which add complexity to the inherent problem in unsteady flow. The study is conducted for flow over NACA0012 airfoil at 600≤Re≤3000 at a low angle of attack. Vibration of flexible structure induces a secondary vortex which modifies the pressure distribution and lift performance of the airfoil. At some moderate vibration amplitude, frequency synchronization or lock-in phenomenon occurs when the vibration frequency is close to the characteristic frequency of rigid airfoil. Evolution and shedding of vortices corresponding to the deformation of flexible structure depends on the Reynolds number. In the case of Re≤1000, the deformation of flexible structure is considered in-phase with the vortex shedding i.e., increasing maximum lift is linked with the positive deformation of flexible structure. At Re=1500 a phase shift of about 1/π exists while they are out-of-phase at Re>1500. Moreover, the oscillation amplitude of lift coefficient increases with increasing vibration amplitude for Re≤1500 while it decreases with increasing vibration amplitude for Re>1500. As a result of frequency lock-in, the average lift coefficient is increased with increasing vibration amplitude for all investigated Reynolds numbers (Re. The maximum increase in the average lift coefficient is 19.72% within the range of investigated parameters.

Student Perceptions of an Upper-Level, Undergraduate Human Anatomy Laboratory Course without Cadavers

Science.gov (United States)

Wright, Shirley J.

2012-01-01

Several programs in health professional education require or are considering requiring upper-level human anatomy as prerequisite for their applicants. Undergraduate students are confronted with few institutions offering such a course, in part because of the expense and logistical issues associated with a cadaver-based human anatomy course. This…

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 of the vibrational distribution function in N2 time varying discharges

International Nuclear Information System (INIS)

Capitelli, M.; Gorse, C.; Ricard, A.

1981-01-01

Relaxation of the electron and vibrational distribution functions have been calculated in function of residence time in nitrogen electrical discharges and post-discharges. In the discharge the vibrational temperature get bigger with the residence time for t -2 s. In the post-discharge the vibrational distribution is evolving in such a manner that the high levels are overpopulated as the low vibrational level population is dropping

Lightweight Vehicle and Driver’s Whole-Body Models for Vibration Analysis

Science.gov (United States)

MdSah, Jamali; Taha, Zahari; Azwan Ismail, Khairul

2018-03-01

Vehicle vibration is a main factor for driving fatigue, discomfort and health problems. The ability to simulate the vibration characteristics in the vehicle and its effects on driver’s whole-body vibration will give significant advantages to designers especially on the vehicle development time and cost. However, it is difficult to achieve optimal condition of ride comfort and handling when using passive suspension system. This paper presents mathematical equations that can be used to describe the vibration characteristics of a lightweight electric vehicle that had been developed. The vehicle’s model was combined with the lumped-parameter model of driver to determine the whole-body vibration level when the vehicle is passing over a road hump using Matlab Simulink. The models were simulated at a constant speed and the results were compared with the experimental data. The simulated vibration level at the vehicle floor and seat were almost similar to the experimental vibration results. The suspension systems that are being used for the solar vehicle are able to reduce the vibration level due to the road hump. The models can be used to simulate and choose the optimal parameters for the suspensions.

Therapeutic CPAP Level Predicts Upper Airway Collapsibility in Patients With Obstructive Sleep Apnea.

Science.gov (United States)

Landry, Shane A; Joosten, Simon A; Eckert, Danny J; Jordan, Amy S; Sands, Scott A; White, David P; Malhotra, Atul; Wellman, Andrew; Hamilton, Garun S; Edwards, Bradley A

2017-06-01

Upper airway collapsibility is a key determinant of obstructive sleep apnea (OSA) which can influence the efficacy of certain non-continuous positive airway pressure (CPAP) treatments for OSA. However, there is no simple way to measure this variable clinically. The present study aimed to develop a clinically implementable tool to evaluate the collapsibility of a patient's upper airway. Collapsibility, as characterized by the passive pharyngeal critical closing pressure (Pcrit), was measured in 46 patients with OSA. Associations were investigated between Pcrit and data extracted from patient history and routine polysomnography, including CPAP titration. Therapeutic CPAP level, demonstrated the strongest relationship to Pcrit (r2=0.51, p CPAP level (6.2 ± 0.6 vs. 10.3 ± 0.4 cmH2O, p -2 cmH2O). A therapeutic CPAP level ≤8.0 cmH2O was sensitive (89%) and specific (84%) for detecting a mildly collapsible upper airway. When applied to the independent validation data set (n = 74), this threshold maintained high specificity (91%) but reduced sensitivity (75%). Our data demonstrate that a patient's therapeutic CPAP requirement shares a strong predictive relationship with their Pcrit and may be used to accurately differentiate OSA patients with mild airway collapsibility from those with moderate-to-severe collapsibility. Although this relationship needs to be confirmed prospectively, our findings may provide clinicians with better understanding of an individual patient's OSA phenotype, which ultimately could assist in determining which patients are most likely to respond to non-CPAP therapies. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Analysis of crack initiation and growth in the high level vibration test at Tadotsu

International Nuclear Information System (INIS)

Kassir, M.K.; Park, Y.J.; Hofmayer, C.H.; Bandyopadhyay, K.K.; Shteyngart, S.

1993-08-01

The High Level Vibration Test data are used to assess the accuracy and usefulness of current engineering methodologies for predicting crack initiation and growth in a cast stainless steel pipe elbow under complex, large amplitude loading. The data were obtained by testing at room temperature a large scale modified model of one loop of a PWR primary coolant system at the Tadotsu Engineering Laboratory in Japan. Fatigue crack initiation time is reasonably predicted by applying a modified local strain approach (Coffin-Mason-Goodman equation) in conjunction with Miner's rule of cumulative damage. Three fracture mechanics methodologies are applied to investigate the crack growth behavior observed in the hot leg of the model. These are: the ΔK methodology (Paris law), ΔJ concepts and a recently developed limit load stress-range criterion. The report includes a discussion on the pros and cons of the analysis involved in each of the methods, the role played by the key parameters influencing the formulation and a comparison of the results with the actual crack growth behavior observed in the vibration test program. Some conclusions and recommendations for improvement of the methodologies are also provided

An Instrument to Determine the Technological Literacy Levels of Upper Secondary School Students

Science.gov (United States)

Luckay, Melanie B.; Collier-Reed, Brandon I.

2014-01-01

In this article, an instrument for assessing upper secondary school students' levels of technological literacy is presented. The items making up the instrument emerged from a previous study that employed a phenomenographic research approach to explore students' conceptions of technology in terms of their understanding of the "nature…

The Health Effects and Keep Down of Whole Body Vibration

Directory of Open Access Journals (Sweden)

Funda Sevencan

2014-04-01

Full Text Available Vibration was defined that oscillation of the body according to the reference point. The tools that are used in industry and are the source of vibration cause diseases. For this reason, the vibration has been one of the factors that affect the health and of the most widely researched in the field of ergonomics. The perceived intensity and health effects of vibration depend on the vibration frequency, intensity, direction, acceleration, duration of exposure, vibration affects the region, age, gender, posture, distance from the source person, activity, time of day and the person\\s overall health condition. The one of the most common health effects of whole body vibration is impact on musculoskeletal system. In many studies, indicated that whole-body vibration effect waist, back, shoulder and neck especially. There were varied studies that hormone levels were not changed as well there were varied studies that hormone levels were increased or decreased. There were varied studies about the digestive and circulatory system. In these studies, digestive system complaints, peptic ulcer, gastritis, varicose veins and hemorrhoids were determined frequently. For protection the health effect of vibration, Directives of the European Commission, Turkish Standards, Assessment and Management of Environmental Noise and Vibration Regulations were published. For the control of vibration are need technical and medical measures and education [TAF Prev Med Bull 2014; 13(2.000: 177-186

Report of workshop on vibration related to fluid in atomic energy field. 7

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

Because of the nonlinearity of the equation that governs flow, sometimes vibration occurs in an unexpected system, and it causes trouble. This 7th workshop on vibration related to fluid in atomic energy field was held at Nuclear Engineering Research Laboratory of University of Tokyo on August 25 and 26, 1997. Two themes were ``Vibration of liquid surface by flow`` and ``Numerical analysis of coupled vibration of fluid-structures``. The former is related to the problem in the development of a demonstration FBR, and the latter is related to the numerical analysis technology such as the handling of boundary conditions and the method of taking position, moving velocity and acceleration into account. This workshop aims at thoroughly discussing a small number of themes, and deepening the understanding. In this report, the summaries of 17 papers are collected, of which the titles are as follows. Liquid surface self-exciting vibration by flow, vibration of upper plenum liquid surface of fast reactor, stability analysis of multiple liquid surfaces, flow instability phenomena of multi-loop system, sloshing in a vessel in which fluid flows, the mechanism of occurrence of self-exciting sloshing in a vessel elucidated by numerical analysis, numerical analysis of manometer vibration excited by flow, numerical analysis of flutter phenomena of aircraft, numerical analysis of aerodynamic elastic problem, mechanism of in-line excitation, numerical analysis of hydrodynamic elastic vibration of tube nest and so on. (K.I.)

Vandenberg Air Force Base Upper Level Wind Launch Weather Constraints

Science.gov (United States)

Shafer, Jaclyn A.; Wheeler, Mark M.

2012-01-01

The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman III ballistic missile. The 30 OSSWF tasked the Applied Meteorology Unit (AMU) to analyze VAFB sounding data with the goal of determining the probability of violating (PoV) their upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a tool that will calculate the PoV of each constraint on the day of launch. In order to calculate the probability of exceeding each constraint, the AMU collected and analyzed historical data from VAFB. The historical sounding data were retrieved from the National Oceanic and Atmospheric Administration Earth System Research Laboratory archive for the years 1994-2011 and then stratified into four sub-seasons: January-March, April-June, July-September, and October-December. The maximum wind speed and 1000-ft shear values for each sounding in each subseason were determined. To accurately calculate the PoV, the AMU determined the theoretical distributions that best fit the maximum wind speed and maximum shear datasets. Ultimately it was discovered that the maximum wind speeds follow a Gaussian distribution while the maximum shear values follow a lognormal distribution. These results were applied when calculating the averages and standard deviations needed for the historical and real-time PoV calculations. In addition to the requirements outlined in the original task plan, the AMU also included forecast sounding data from the Rapid Refresh model. This information provides further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours on day of launch. The interactive graphical user interface (GUI) for this project was developed in

Levels of vibration transmitted to the operator of the tractor equipped with front axle suspension

Directory of Open Access Journals (Sweden)

Daniele Pochi

2013-09-01

Full Text Available In recent years the comfort and the preservation of the health of the operators became central issues in the evolution of agricultural machinery and led to the introduction of devices aimed at improving working conditions. Thereby, for instance, the presence of air conditioner, soundproof cab and driver seat suspension became normal on agricultural tractors. The vibrations are one of the most complex issues to deal with, being determined by the characteristics and interaction of elements such as tyres, axles, mainframe, cab and seat suspension. In this respect, manufacturers are trying to improve their products, even integrating these elements with new devices such as the suspension on the front axle of the tractor, aimed at reducing the level of vibrations during the transfers at high speed. One of these underwent tests at CRA-ING. Since its purpose is to reduce the level of vibration transmitted to the driver, their measurements in different points of the tractor and in different operating conditions, were compared in order to evaluate the effectiveness of the device, expressed as time of exposure. The suspension system of the front axle is designed to absorb the oscillations (especially pitching determined by irregularities in the road surface, allowing an increased control of the vehicle at high speed, as demonstrated by the test results and confirmed by the driving impressions outlined by the operator. The action of the device under these conditions results in an increase of the exposure time, important fact because of the relevance of the road transfer operations of tractors with mounted implements or trailers to tow and of the tendency to increase the speed limit for the road tractors (in Germany were brought to 50 km h–1 for several years. The action just described is less evident with increasing irregularity of the road surface and with the decrease of the travel speed. Nevertheless, in such conditions, the device appears to

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

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

Evaluation of blast-induced vibration effects on structures 1

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Rim; Jeon, Gyu Shick; Lee, Dae Soo; Joo, Kwang Ho; Lee, Woong Keon [Korea Electrotechnology Research Inst., Changwon (Korea, Republic of); Ryu, Chang Ha; Chung, So Keul; Lee, Kyung Won; Shin, Hee Soon; Chun, Sun Woo; Park, Yeon Jun; Synn, Joong Ho; Choi, Byung Hee [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-12-31

Due to the difficulties of obtaining construction site for new plants, following ones are inevitably being built in the site adjacent to existing power plants. Therefore considerable thought has been recently given to the dynamic loading generated by blasting works near the plants to maintain the safety of structures and facilities in power plants. Our own standard for safety level of blast vibration is not prepared yet, and foreign standards have been generally employed without theoretical and experimental verification. Safety-related structures of power plants and facilities have to be protected against the effects of possible hazards due to blast vibration. Earthquakes have been considered a major dynamic design loading as a requirement of plant design, but the effects of blast-induced vibration are not. In order to ensure the safety, rational safe criterion should be established and blast design should be satisfy it, which requires the development of a model for prediction of vibration level through more systematic measurement and analysis. The main objectives of the study are : to provide background data for establishing the rational safe vibration limits, to develop models for prediction of blast vibration level, to establish safe blast design criterion, and to accumulate techniques for field measurements, data acquisition and analysis (author). 80 refs., 347 figs.

Effects of wrist tendon vibration on arm tracking in people poststroke.

Science.gov (United States)

Conrad, Megan O; Scheidt, Robert A; Schmit, Brian D

2011-09-01

The goal of this study was to evaluate the influence of wrist tendon vibration on a multijoint elbow/shoulder tracking task. We hypothesized that tendon vibration applied at the wrist musculature would improve upper arm tracking performance in chronic stroke survivors through increased, Ia-afferent feedback to the central nervous system (CNS). To test this hypothesis, 10 chronic stroke and 5 neurologically intact subjects grasped the handle of a planar robot as they tracked a target through a horizontal figure-8 pattern. A total of 36 trials were completed by each subject. During the middle trials, 70-Hz tendon vibration was applied at the wrist flexor tendons. Position, velocity, and electromyography data were evaluated to compare the quality of arm movements before, during, and after trials with concurrent vibration. Despite tracking a target that moved at a constant velocity, hand trajectories appeared to be segmented, displaying alternating intervals of acceleration and deceleration. Segments were identifiable in tangential velocity data as single-peaked, bell-shaped speed pulses. When tendon vibration was applied at the wrist musculature, stroke subjects experienced improved tracking performance in that hand path lengths and peak speed variability decreased, whereas movement smoothness increased. These performance improvements were accompanied by decreases in the muscle activity during movement. Possible mechanisms behind improved movement control in response to tendon vibration may include improved sensorimotor integration or improved cortical modulation of spinal reflex activity.

FORECASTING OF DURABILITY OF ASPHALT PAVEMENT ON THE BASIS OF LEVELS OF THEIR VIBRATION LOADING

Directory of Open Access Journals (Sweden)

V. A. Osinovskaya

2015-01-01

Full Text Available The problem of low durability of flexible pavement is one of the most important problems of road economy. For example, the actual service life of asphalt pavement in Russia about 3 … 5 years. The bad condition of highways is an obstacle for the development of the national economy and leads to a significant annual economic losses.At present, this problem has no exact solution. Even at the seeming good road conditions of Europe and America the problem of low durability is no less important in these countries. And this problem becomes more and more actual every year.Our scientific researches allowed to make a hypothesis that the projected of pavements are not have the necessary durability yet not of a stage of designing because in strength calculations did not take into account the vibration of road constructions.Very actual the vibration loading becomes today as is now significantly changed the nature of loading of pavements. As a result the deflections of a pavements are reduced, but the increased vibration of pavements accelerated processes of destruction and significantly reduced durability.The theory of vibration destruction developed by the author allows to adjust the vibration, to form the vibration resistance pavements, and also to forecast a residual life of pavements that will more effectively develop repair actions.

Input Shaping to Reduce Solar Array Structural Vibrations

Science.gov (United States)

Doherty, Michael J.; Tolson, Robert J.

1998-01-01

Structural vibrations induced by actuators can be minimized using input shaping. Input shaping is a feedforward method in which actuator commands are convolved with shaping functions to yield a shaped set of commands. These commands are designed to perform the maneuver while minimizing the residual structural vibration. In this report, input shaping is extended to stepper motor actuators. As a demonstration, an input-shaping technique based on pole-zero cancellation was used to modify the Solar Array Drive Assembly (SADA) actuator commands for the Lewis satellite. A series of impulses were calculated as the ideal SADA output for vibration control. These impulses were then discretized for use by the SADA stepper motor actuator and simulated actuator outputs were used to calculate the structural response. The effectiveness of input shaping is limited by the accuracy of the knowledge of the modal frequencies. Assuming perfect knowledge resulted in significant vibration reduction. Errors of 10% in the modal frequencies caused notably higher levels of vibration. Controller robustness was improved by incorporating additional zeros in the shaping function. The additional zeros did not require increased performance from the actuator. Despite the identification errors, the resulting feedforward controller reduced residual vibrations to the level of the exactly modeled input shaper and well below the baseline cases. These results could be easily applied to many other vibration-sensitive applications involving stepper motor actuators.

Radiation level analysis for the port cell of the ITER electron cyclotron-heating upper launcher

Energy Technology Data Exchange (ETDEWEB)

Weinhorst, Bastian, E-mail: bastian.weinhorst@kit.edu [KIT, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Fischer, Ulrich; Lu, Lei [KIT, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Strauss, Dirk; Spaeh, Peter; Scherer, Theo [KIT, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Leichtle, Dieter [F4E, Analysis & Codes/Technical Support Services, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain)

2016-11-01

Highlights: • First detailed neutronic modelling of the ECHUL port cell with ECHUL equipment (including beam lines with diamond windows, the beam lines mounting box, conduit boxes and rails). • Three different bioshield port plug configurations and two different neutron source configurations are investigated. • Radiation Levels are calculated in the port cell, focusing on the position of the diamond window. • The dose rate in the port cell is below the limit for maintenance in the port cell. • The radiation level at the diamond window is very low and should not influence its performance. - Abstract: The electron cyclotron-heating upper launcher (ECHUL) will be installed in four upper ports of the ITER tokamak thermonuclear fusion reactor. Each ECHUL is able to deposit 8 MW power into the plasma for plasma mode stabilization via microwave beam lines. An essential part of these beam lines are the diamond windows. They are located in the upper port cell behind the bioshield to reduce the radiation levels to a minimum. The paper describes the first detailed neutronic modelling of the ECHUL port cell with ECHUL equipment. The bioshield plug is modelled including passageways for the microwave beam lines, piping and cables looms as well as rails and openings for ventilation. The port cell is equipped with the beam lines including the diamond windows, the beam lines mounting box, conduit boxes and rails. The neutrons are transported into the port cell starting from a surface source in front of the bioshield. Neutronic results are obtained for radiation levels in the port cell at different positions, mainly focusing on the diamond windows position. It is shown that the radiation level is below the limit for maintenance in the port cell. The radiation level at the diamond window is very low and should not influence its performance.

Study on vibration behaviors of engineered barrier system

International Nuclear Information System (INIS)

Mikoshiba, Tadashi; Ogawa, Nobuyuki; Minowa, Chikahiro

1998-01-01

High-level radioactive wastes have been buried underground by packing into a strong sealed container made from carbon steel (over-pack) with buffer material (bentonite). The engineered barrier system constructed with an overpack and buffer materials must be resistant to earthquakes as well as invasion of groundwater for a long period. Therefore, seismic evaluation of barrier system for earthquakes is indispensable especially in Japan to keep its structural safety. Here, the effects of earthquake vibration on the engineered barrier systems were investigated experimentally. Random-wave vibration and practical seismic wave one were loaded for the systems and fundamental data were obtained. For the former vibration the response characteristics of both engineered barrier models constructed with overpack and bentonite were non-linear. For the latter one, the stress in bentonite was increased in proportion to the vibration level. (M.N.)

Fundamental study on the new method to estimate vibration level on a ship. Formulation of the damping matrix based on dissipation energy caused by fluid viscosity; Senpaku no shindo level suitei ni kansuru kisoteki kenkyu. Ryutai no nensei ni yoru san`itsu energy ni motozuku gensui matrix no teishikika

Energy Technology Data Exchange (ETDEWEB)

Funaki, T.; Hayashi, S. [Osaka University, Osaka (Japan). Faculty of engineering

1996-12-31

It is known in estimating vibration characteristics of a ship that fluid range affects largely a structure. In order to analyze the compound vibration therein, a method was proposed, which estimates vibration levels without using the finite element method. However, the problem of mode decay ratio has not been solved. Therefore, this paper first describes a method to introduce an equivalent linear decay matrix. The paper then mentions difference in the decay effects due to fluid viscosity in a shallow and deep water regions. Furthermore, vibration levels in the deep water region were estimated in a model experiment to verify the estimation result. Under a hypothesis that two-node vibration in a rotating ellipse has displacement distributions in the deep and shallow water regions equivalent, and when a case of vibration in a layer flow condition is calculated, dissipation energy in the shallow region is larger than that in the deep region by about 26%. About 5% of the total dissipation energy is consumed at bottom of the sea. According to a frequency response calculation, estimated values for the response levels still differ from experimental values, although the trend that the vibration levels change can be reproduced. 6 refs., 15 figs., 2 tabs.

Fundamental study on the new method to estimate vibration level on a ship. Formulation of the damping matrix based on dissipation energy caused by fluid viscosity; Senpaku no shindo level suitei ni kansuru kisoteki kenkyu. Ryutai no nensei ni yoru san`itsu energy ni motozuku gensui matrix no teishikika

Energy Technology Data Exchange (ETDEWEB)

Funaki, T; Hayashi, S [Osaka University, Osaka (Japan). Faculty of engineering

1997-12-31

It is known in estimating vibration characteristics of a ship that fluid range affects largely a structure. In order to analyze the compound vibration therein, a method was proposed, which estimates vibration levels without using the finite element method. However, the problem of mode decay ratio has not been solved. Therefore, this paper first describes a method to introduce an equivalent linear decay matrix. The paper then mentions difference in the decay effects due to fluid viscosity in a shallow and deep water regions. Furthermore, vibration levels in the deep water region were estimated in a model experiment to verify the estimation result. Under a hypothesis that two-node vibration in a rotating ellipse has displacement distributions in the deep and shallow water regions equivalent, and when a case of vibration in a layer flow condition is calculated, dissipation energy in the shallow region is larger than that in the deep region by about 26%. About 5% of the total dissipation energy is consumed at bottom of the sea. According to a frequency response calculation, estimated values for the response levels still differ from experimental values, although the trend that the vibration levels change can be reproduced. 6 refs., 15 figs., 2 tabs.

[Occupational standing vibration rate and vibrational diseases].

Science.gov (United States)

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

2003-12-01

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

Development of adaptive helicopter seat systems for aircrew vibration mitigation

Science.gov (United States)

Chen, Yong; Wickramasinghe, Viresh; Zimcik, David G.

2008-03-01

Helicopter aircrews are exposed to high levels of whole body vibration during flight. This paper presents the results of an investigation of adaptive seat mount approaches to reduce helicopter aircrew whole body vibration levels. A flight test was conducted on a four-blade helicopter and showed that the currently used passive seat systems were not able to provide satisfactory protection to the helicopter aircrew in both front-back and vertical directions. Long-term exposure to the measured whole body vibration environment may cause occupational health issues such as spine and neck strain injuries for aircrew. In order to address this issue, a novel adaptive seat mount concept was developed to mitigate the vibration levels transmitted to the aircrew body. For proof-of-concept demonstration, a miniature modal shaker was properly aligned between the cabin floor and the seat frame to provide adaptive actuation authority. Adaptive control laws were developed to reduce the vibration transmitted to the aircrew body, especially the helmet location in order to minimize neck and spine injuries. Closed-loop control test have been conducted on a full-scale helicopter seat with a mannequin configuration and a large mechanical shaker was used to provide representative helicopter vibration profiles to the seat frame. Significant vibration reductions to the vertical and front-back vibration modes have been achieved simultaneously, which verified the technical readiness of the adaptive mount approach for full-scale flight test on the vehicle.

Theoretical rotation-vibration spectrum of thioformaldehyde

International Nuclear Information System (INIS)

Yachmenev, Andrey; Polyak, Iakov; Thiel, Walter

2013-01-01

We present a variational calculation of the first comprehensive T = 300 K rovibrational line list for thioformaldehyde, H 2 CS. It covers 41 809 rovibrational levels for states up to J max = 30 with vibrational band origins up to 5000 cm −1 and provides the energies and line intensities for 547 926 transitions from the ground vibrational state to these levels. It is based on our previously reported accurate ab initio potential energy surface and a newly calculated ab initio dipole moment surface. Minor empirical adjustments are made to the ab initio equilibrium geometry to reduce systematic errors in the predicted intra-band rotational energy levels. The rovibrational energy levels and transition intensities are computed variationally by using the methods implemented in the computer program TROVE. Transition wavelengths and intensities are found to be in excellent agreement with the available experimental data. The present calculations correctly reproduce the observed resonance effects, such as intensity borrowing, thus reflecting the high accuracy of the underlying ab initio surfaces. We report a detailed analysis of several vibrational bands, especially those complicated by strong Coriolis coupling, to facilitate future laboratory assignments

Theoretical rotation-vibration spectrum of thioformaldehyde

Science.gov (United States)

Yachmenev, Andrey; Polyak, Iakov; Thiel, Walter

2013-11-01

We present a variational calculation of the first comprehensive T = 300 K rovibrational line list for thioformaldehyde, H2CS. It covers 41 809 rovibrational levels for states up to Jmax = 30 with vibrational band origins up to 5000 cm-1 and provides the energies and line intensities for 547 926 transitions from the ground vibrational state to these levels. It is based on our previously reported accurate ab initio potential energy surface and a newly calculated ab initio dipole moment surface. Minor empirical adjustments are made to the ab initio equilibrium geometry to reduce systematic errors in the predicted intra-band rotational energy levels. The rovibrational energy levels and transition intensities are computed variationally by using the methods implemented in the computer program TROVE. Transition wavelengths and intensities are found to be in excellent agreement with the available experimental data. The present calculations correctly reproduce the observed resonance effects, such as intensity borrowing, thus reflecting the high accuracy of the underlying ab initio surfaces. We report a detailed analysis of several vibrational bands, especially those complicated by strong Coriolis coupling, to facilitate future laboratory assignments.

Theoretical rotation-vibration spectrum of thioformaldehyde

Energy Technology Data Exchange (ETDEWEB)

Yachmenev, Andrey [Department of Physics and Astronomy, University College London, London, WC1E 6BT (United Kingdom); Polyak, Iakov; Thiel, Walter [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D–45470 Mülheim an der Ruhr (Germany)

2013-11-28

We present a variational calculation of the first comprehensive T = 300 K rovibrational line list for thioformaldehyde, H{sub 2}CS. It covers 41 809 rovibrational levels for states up to J{sub max} = 30 with vibrational band origins up to 5000 cm{sup −1} and provides the energies and line intensities for 547 926 transitions from the ground vibrational state to these levels. It is based on our previously reported accurate ab initio potential energy surface and a newly calculated ab initio dipole moment surface. Minor empirical adjustments are made to the ab initio equilibrium geometry to reduce systematic errors in the predicted intra-band rotational energy levels. The rovibrational energy levels and transition intensities are computed variationally by using the methods implemented in the computer program TROVE. Transition wavelengths and intensities are found to be in excellent agreement with the available experimental data. The present calculations correctly reproduce the observed resonance effects, such as intensity borrowing, thus reflecting the high accuracy of the underlying ab initio surfaces. We report a detailed analysis of several vibrational bands, especially those complicated by strong Coriolis coupling, to facilitate future laboratory assignments.

Theoretical and experimental study of vibration, generated by monorail trains

Science.gov (United States)

Rybak, Samuil A.; Makhortykh, Sergey A.; Kostarev, Stanislav A.

2002-11-01

Monorail transport as all other city transport vehicles is the source of high noise and vibration levels. It is less widespread than cars or underground transport but its influence in modern cities enhances. Now in Moscow the first monorail road with trains on tires is designed, therefore the problem of vibration and noise assessments and prediction of its impact on the residential region appears. To assess the levels of generated vibration a physical model of interaction in the system wagon-tire-road coating-viaduct-soil has been proposed and then numerically analyzed. The model is based on the known from publications facts of automobile transport vibration and our own practice concerning underground trains vibration generation. To verify computer simulation results and adjust model parameters the series of measurements of noise and vibration near experimental monorail road was carried out. In the report the results of calculations and measurements will be presented and some outcomes of possible acoustical ecologic situation near monorail roads will be proposed.

Recovering Intrinsic Fragmental Vibrations Using the Generalized Subsystem Vibrational Analysis.

Science.gov (United States)

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

2018-05-08

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

Analysis and wafer-level design of a high-order silicon vibration isolator for resonating MEMS devices

International Nuclear Information System (INIS)

Yoon, Sang Won; Lee, Sangwoo; Najafi, Khalil; Perkins, Noel C

2011-01-01

This paper presents the analysis and preliminary design, fabrication, and measurement for mechanical vibration-isolation platforms especially designed for resonating MEMS devices including gyroscopes. Important parameters for designing isolation platforms are specified and the first platform (in designs with cascaded multiple platforms) is crucial for improving vibration-isolation performance and minimizing side-effects on integrated gyroscopes. This isolation platform, made from a thick silicon wafer substrate for an environment-resistant MEMS package, incorporates the functionalities of a previous design including vacuum packaging and thermal resistance with no additional resources. This platform consists of platform mass, isolation beams, vertical feedthroughs, and bonding pads. Two isolation platform designs follow from two isolation beam designs: lateral clamped–clamped beams and vertical torsion beams. The beams function simultaneously as mechanical springs and electrical interconnects. The vibration-isolation platform can yield a multi-dimensional, high-order mechanical low pass filter. The isolation platform possesses eight interconnects within a 12.2 × 12.2 mm 2 footprint. The contact resistance ranges from 4–11 Ω depending on the beam design. Vibration measurements using a laser-Doppler vibrometer demonstrate that the lateral vibration-isolation platform suppresses external vibration having frequencies exceeding 2.1 kHz.

Experimental chaos in nonlinear vibration isolation system

International Nuclear Information System (INIS)

Lou Jingjun; Zhu Shijian; He Lin; He Qiwei

2009-01-01

The chaotic vibration isolation method was studied thoroughly from an experimental perspective. The nonlinear load-deflection characteristic of the conical coil spring used in the experiment was surveyed. Chaos and subharmonic responses including period-2 and period-6 motions were observed. The line spectrum reduction and the drop of the acceleration vibration level in chaotic state and that in non-chaotic state were compared, respectively. It was concluded from the experiment that the nonlinear vibration isolation system in chaotic state has strong ability in line spectrum reduction.

Energy expenditure and substrate utilization during whole body vibration

Directory of Open Access Journals (Sweden)

Ravena Santos Raulino

2015-04-01

Full Text Available INTRODUCTION AND OBJECTIVE: the aim of this study was to investigate whether the addition of vibration during interval training would raise oxygen consumption VO2 to the extent necessary for weight management and to evaluate the influence of the intensity of the vibratory stimulus for prescribing the exercise program in question. METHODS: VO2, measured breath by breath, was evaluated at rest and during the four experimental conditions to determine energy expenditure, metabolic equivalent MET, respiratory exchange ratio RER, % Kcal from fat, and rate of fat oxidation. Eight young sedentary females age 22±1 years, height 163.88± 7.62 cm, body mass 58.35±10.96 kg, and VO2 max 32.75±3.55 mLO2.Kg-1.min-1 performed interval training duration = 13.3 min to the upper and lower limbs both with vibration 35 Hz and 2 mm, 40 Hz and 2 mm, 45 Hz and 2 mm and without vibration. The experimental conditions were randomized and balanced at an interval of 48 hours. RESULTS: the addition of vibration to exercise at 45 Hz and 2 mm resulted in an additional increase of 17.77±12.38% of VO2 compared with exercise without vibration. However, this increase did not change the fat oxidation rate p=0.42 because intensity of exercise 29.1±3.3 %VO2max, 2.7 MET was classified as mild to young subjects. CONCLUSION: despite the influence of vibration on VO2 during exercise, the increase was insufficient to reduce body weight and did not reach the minimum recommendation of exercise prescription for weight management for the studied population.

Dynamic Analysis of an Office Building due to Vibration from Road Construction Activities

Science.gov (United States)

Chik, T. N. T.; Kamil, M. R. H.; Yusoff, N. A.; Ibrahim, M. H. W.

2018-04-01

Construction activities are widely known as one of the predominant sources of man-made vibrations that able to create nuisance towards any adjacent building, and this includes the road construction operations. Few studies conclude the construction-induced vibration may be harmful directly and indirectly towards the neighbouring building. This lead to the awareness of study the building vibration response of concrete masonry load bearing system and its vibrational performance towards the road construction activities. This study will simulate multi-storey office building of Sekolah Menengah Kebangsaan (SMK) Bandar Enstek at Negeri Sembilan by using finite element vibration analyses. The excitation of transient loads from ground borne vibrations which triggered by the road construction activities are modelled into the building. The vibration response was recorded during in-situ ambient vibration test by using Laser Doppler Vibrometer (LDV), which specifically performed on four different locations. The finite element simulation process was developed in the commercial FEA software ABAQUS. Then, the experimental data was processed and evaluated in MATLAB ModalV to assess the vibration criteria of the floor in building. As a result, the vibration level of floor in building is fall under VC-E curve which was under the maximum permissible level for office building (VC-ISO). The vibration level on floor is acceptable within the limit that have been referred.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: AMSU-A1 EOS Instrument, (S/N 202) Qualification Level Vibration Tests of August/September 1998, (S/O 565632, OC-417) Plus Addendum A

Science.gov (United States)

Heffer, R.

1998-01-01

The purpose of this report is to present a qualification level vibration testing performed on the S/N 202, EOS AMSU-A1 Instrument was vibration tested to qualification levels per the Ref. 1 shop order. The instrument withstood the 8 g sine sweep test, the 7.5 Grms random vibration test, and the 18.75 g sine burst test in each of the three orthogonal axes. Some loss of transmissibility, however, is seen in the lower reflector after Z-axis random vibration. The test sequence was not without incidence. Failure of Channel 7 in the Limited Performance Test (LPT) performed after completion of the 1 st (X-axis) axis vibration sequence, required replacement of the DRO and subsequent re-testing of the instrument. The post-vibration comprehensive performance test (CPT) was successfully run after completion of the three axes of vibration with the replacement component installed in the instrument. Passing the CPT signified the successful completion of the S/N 202 A1 qualification vibration testing.

Effect of shelf aging on vibration transmissibility of anti-vibration gloves

Science.gov (United States)

SHIBATA, Nobuyuki

2017-01-01

Anti-vibration gloves have been used in real workplaces to reduce vibration transmitted through hand-held power tools to the hand. Generally materials used for vibration attenuation in gloves are resilient materials composed of certain synthetic and/or composite polymers. The mechanical characteristics of the resilient materials used in anti-vibration gloves are prone to be influenced by environmental conditions such as temperature, humidity, and photo-irradiation, which cause material degradation and aging. This study focused on the influence of shelf aging on the vibration attenuation performance of air-packaged anti-vibration gloves following 2 yr of shelf aging. Effects of shelf aging on the vibration attenuation performance of anti-vibration gloves were examined according to the Japan industrial standard JIS T8114 test protocol. The findings indicate that shelf aging induces the reduction of vibration attenuation performance in air-packaged anti-vibration gloves. PMID:28978817

Flow Induced Vibration Program at Argonne National Laboratory

Science.gov (United States)

1984-01-01

The Argonne National Laboratory's Flow Induced Vibration Program, currently residing in the Laboratory's Components Technology Division is discussed. Throughout its existence, the overall objective of the program was to develop and apply new and/or improved methods of analysis and testing for the design evaluation of nuclear reactor plant components and heat exchange equipment from the standpoint of flow induced vibration. Historically, the majority of the program activities were funded by the US Atomic Energy Commission, the Energy Research and Development Administration, and the Department of Energy. Current DOE funding is from the Breeder Mechanical Component Development Division, Office of Breeder Technology Projects; Energy Conversion and Utilization Technology Program, Office of Energy Systems Research; and Division of Engineering, Mathematical and Geosciences, office of Basic Energy Sciences. Testing of Clinch River Breeder Reactor upper plenum components was funded by the Clinch River Breeder Reactor Plant Project Office. Work was also performed under contract with Foster Wheeler, General Electric, Duke Power Company, US Nuclear Regulatory Commission, and Westinghouse.

Mechanism of bubble detachment from vibrating walls

Energy Technology Data Exchange (ETDEWEB)

Kim, Dongjun; Park, Jun Kwon, E-mail: junkeun@postech.ac.kr; Kang, Kwan Hyoung [Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of); Kang, In Seok [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of)

2013-11-15

We discovered a previously unobserved mechanism by which air bubbles detach from vibrating walls in glasses containing water. Chaotic oscillation and subsequent water jets appeared when a wall vibrated at greater than a critical level. Wave forms were developed at water-air interface of the bubble by the wall vibration, and water jets were formed when sufficiently grown wave-curvatures were collapsing. Droplets were pinched off from the tip of jets and fell to the surface of the glass. When the solid-air interface at the bubble-wall attachment point was completely covered with water, the bubble detached from the wall. The water jets were mainly generated by subharmonic waves and were generated most vigorously when the wall vibrated at the volume resonant frequency of the bubble. Bubbles of specific size can be removed by adjusting the frequency of the wall's vibration.

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.

Numerical investigations of two-degree-of-freedom vortex-induced vibration in shear flow

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hui; Liu, Mengke; Han, Yang; Li, Jian; Gui, Mingyue; Chen, Zhihua, E-mail: zhanghui1902@hotmail.com [Science and Technology on Transient Physics Laboratory, Nanjing University of Science and Technology, Nanjing 210094 (China)

2017-06-15

Exponential-polar coordinates attached to a moving cylinder are used to deduce the stream function-vorticity equations for two-degree-of-freedom vortex-induced vibration, the initial and boundary conditions, and the distribution of the hydrodynamic force, which consists of the vortex-induced force, inertial force, and viscous damping force. The fluid-structure interactions occurring from the motionless cylinder to the steady vibration are investigated numerically, and the variations of the flow field, pressure, lift/drag, and cylinder displacement are discussed. Both the dominant vortex and the cylinder shift, whose effects are opposite, affect the shear layer along the transverse direction and the secondary vortex along the streamwise direction. However, the effect of the cylinder shift is larger than that of the dominant vortices. Therefore, the former dominates the total effects of the flow field. Moreover, the symmetry of the flow field is broken with the increasing shear rate. With the effect of the background vortex, the upper vortices are strengthened, and the lower vortices are weakened; thus, the shear layer and the secondary vortices induced by the upper shedding vortices are strengthened, while the shear layer and the secondary vortices induced by the lower shedding vortices are weakened. Therefore, the amplitudes of the displacement and drag/lift dominated by the upper vortex are larger than those of the displacement and drag/lift dominated by the lower vortex. (paper)

Student Perceived and Determined Knowledge of Biology Concepts in an Upper-Level Biology Course

Science.gov (United States)

Ziegler, Brittany; Montplaisir, Lisa

2014-01-01

Students who lack metacognitive skills can struggle with the learning process. To be effective learners, students should recognize what they know and what they do not know. This study examines the relationship between students' perception of their knowledge and determined knowledge in an upper-level biology course utilizing a pre/posttest…

Analysis of Vibration Diagnostics Methods for Induction Motors

Directory of Open Access Journals (Sweden)

A. P. Kalinov

2012-01-01

Full Text Available The paper presents an analysis of existing vibration diagnostics methods. In order to evaluate an efficiency of method application the following criteria have been proposed: volume of input data required for establishing diagnosis, data content, software and hardware level, execution time for vibration diagnostics. According to the mentioned criteria a classification of vibration diagnostics methods for determination of their advantages and disadvantages, search for their development and improvement has been presented in paper. The paper contains a comparative estimation of methods in accordance with the proposed  criteria. According to this estimation the most efficient methods are a spectral analysis and spectral analysis of the vibration signal envelope.

Determination of fuel assembly vibrational modes through analysis of incore detector noise

International Nuclear Information System (INIS)

Johnson, R.S.

1986-01-01

In order to better characterize fuel assembly vibration at Duke Power Company's Oconee Nuclear Station, incore noise data were acquired an analyzed from prompt responding detectors incorporated in the Oconee 2, Cycle 7 core. Duke Power Company began actively pursuing an inhouse Neutron Noise Analysis program for routine surveillance of reactor internals vibration in 1979. Noise data has since been acquired and analyzed for twelve cycles of operation for the three Oconee units. Duke Power's Oconee Unit 2 is a Babcock and Wilcoxs pressurized water reactor with a rate thermal power of 2568MW. For Oconee 2, Cycle 7 operation, two test assemblies, each employing a string of seven axially-spaced, prompt responding hafnium detectors, were included in the final core design. Incore detector noise data were obtained during Cycle 7 at approximately 281 and 430 effective full power days (EFPD). In addition to the incore test detector signals, noise signals from the upper and lower chambers of the four excore power range detectors were recorded to aid in the analysis. The comparison of RMS signal levels for each incore detector and the phase relationships between detector locations within two test assemblies identified the first four fuel assembly bending modes associated with fixed end conditions

Studies of interstellar vibrationally-excited molecules

International Nuclear Information System (INIS)

Ziurys, L.M.; Snell, R.L.; Erickson, N.R.

1986-01-01

Several molecules thus far have been detected in the ISM in vibrationally-excited states, including H 2 , SiO, HC 3 N, and CH 3 CN. In order for vibrational-excitation to occur, these species must be present in unusually hot and dense gas and/or where strong infrared radiation is present. In order to do a more thorough investigation of vibrational excitation in the interstellar medium (ISM), studies were done of several mm-wave transitions originating in excited vibrational modes of HCN, an abundant interstellar molecule. Vibrationally-excited HCN was recently detected toward Orion-KL and IRC+10216, using a 12 meter antenna. The J=3-2 rotational transitions were detected in the molecule's lowest vibrational state, the bending mode, which is split into two separate levels, due to l-type doubling. This bending mode lies 1025K above ground state, with an Einstein A coefficient of 3.6/s. The J=3-2 line mode of HCN, which lies 2050K above ground state, was also observed toward IRC+10216, and subsequently in Orion-KL. Further measurements of vibrationally-excited HCN were done using a 14 meter telescope, which include the observations of the (0,1,0) and (0,2,0) modes towards Orion-KL, via their J=3-2 transitions at 265-267 GHz. The spectrum of the J=3-2 line in Orion taken with the 14 meter telescope, is shown, along with a map, which indicates that emission from vibrationally-excited HCN arises from a region probably smaller than the 14 meter telescope's 20 arcsec beam

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

Noise and vibration levels in artificial polar bear dens as related to selected petroleum exploration and developmental activities

International Nuclear Information System (INIS)

Blix, A.S.; Lentfer, J.W.

1992-01-01

Petroleum exploration and development are occurring in various locations in the Arctic, where there are important denning sites for polar bears. Petroleum activities usually coincide with winter denning activities by bears, who may abandon dens if subject to prolonged annoyance. A study was carried out to measure noise and vibration levels in artificial polar bear dens at Prudhoe's Bar, Alaska, resulting from seismic testing, drilling and transport. A microphone and an accelerometer were frozen to the floor of the dens, with leads passed through a consolidated snow filled entrance to a truck, tent or helicopter. Tests were carried out on land, sea ice, and next to a drilling tower on an artificial island, which was also used to measure noise levels resulting from a helicopter taking off. It was concluded that the dry and wind-beaten arctic snow muffles both sound and vibration extremely well, and it is unlikely that polar bears in their dens will be disturbed by the type of petroleum-related activities measured, provided they do not take place within 100 m of the dens. 8 refs., 7 figs., 1 tab

Vibration monitoring of large generator stator and-winding

International Nuclear Information System (INIS)

Duffeau, F.; Bernard, P.

1999-01-01

Large generators of French Nuclear Power plants are equipped with a standardised vibration monitoring system. The first aim of these new systems is to protect the machines by generating alarms in the control room when predefined vibration thresholds have been over-passed. Secondly, this specially designed instrumentation permits to create a National data base allowing to compare different generators of the same technology. Additionally, statistical methods have been developed in order to 'guess' vibration level at several locations of the stator end-windings, depending on the actual operating parameters of the generator, i.e. reactive and active power load. So this paper presents the general concept of the vibration monitoring of EDF large generator stators and deals with a new method to predict vibrations in different locations under control. (authors)

Classification of upper limb disability levels of children with spastic unilateral cerebral palsy using K-means algorithm.

Science.gov (United States)

Raouafi, Sana; Achiche, Sofiane; Begon, Mickael; Sarcher, Aurélie; Raison, Maxime

2018-01-01

Treatment for cerebral palsy depends upon the severity of the child's condition and requires knowledge about upper limb disability. The aim of this study was to develop a systematic quantitative classification method of the upper limb disability levels for children with spastic unilateral cerebral palsy based on upper limb movements and muscle activation. Thirteen children with spastic unilateral cerebral palsy and six typically developing children participated in this study. Patients were matched on age and manual ability classification system levels I to III. Twenty-three kinematic and electromyographic variables were collected from two tasks. Discriminative analysis and K-means clustering algorithm were applied using 23 kinematic and EMG variables of each participant. Among the 23 kinematic and electromyographic variables, only two variables containing the most relevant information for the prediction of the four levels of severity of spastic unilateral cerebral palsy, which are fixed by manual ability classification system, were identified by discriminant analysis: (1) the Falconer index (CAI E ) which represents the ratio of biceps to triceps brachii activity during extension and (2) the maximal angle extension (θ Extension,max ). A good correlation (Kendall Rank correlation coefficient = -0.53, p = 0.01) was found between levels fixed by manual ability classification system and the obtained classes. These findings suggest that the cost and effort needed to assess and characterize the disability level of a child can be further reduced.

Analytical stiffness calculations of a cone-shaped magnetic vibration isolator for a micro balance

NARCIS (Netherlands)

Casteren, van D.T.E.H.; Paulides, J.J.H.; Janssen, J.L.G.; Lomonova, E.A.

2013-01-01

The accuracy of a micro balance is highly dependent on the level of floor vibrations. One strategy to reduce floor vibrations is a magnetic vibration isolator. Magnetic vibration isolators have the possibility to obtain a zero-stiffness region, which is beneficial for attenuating vibrations. In this

Combined Effects of High-Speed Railway Noise and Ground Vibrations on Annoyance.

Science.gov (United States)

Yokoshima, Shigenori; Morihara, Takashi; Sato, Tetsumi; Yano, Takashi

2017-07-27

The Shinkansen super-express railway system in Japan has greatly increased its capacity and has expanded nationwide. However, many inhabitants in areas along the railways have been disturbed by noise and ground vibration from the trains. Additionally, the Shinkansen railway emits a higher level of ground vibration than conventional railways at the same noise level. These findings imply that building vibrations affect living environments as significantly as the associated noise. Therefore, it is imperative to quantify the effects of noise and vibration exposures on each annoyance under simultaneous exposure. We performed a secondary analysis using individual datasets of exposure and community response associated with Shinkansen railway noise and vibration. The data consisted of six socio-acoustic surveys, which were conducted separately over the last 20 years in Japan. Applying a logistic regression analysis to the datasets, we confirmed the combined effects of vibration/noise exposure on noise/vibration annoyance. Moreover, we proposed a representative relationship between noise and vibration exposures, and the prevalence of each annoyance associated with the Shinkansen railway.

Effects of nuclear vibration on the ionization process of H2+ in ultrashort intense laser field

International Nuclear Information System (INIS)

Phan, Ngoc-Loan; Nguyen, Ngoc-Ty; Truong, Tran-Chau

2015-01-01

By numerically solving the time-dependent Schrödinger equation, we calculate the ionization probability of a vibrating H 2 + exposed to ultrashort intense laser fields. The results show that the ionization probability increases by time and gets a saturation value. We also find that with some first vibration levels, the ionization probability from a higher vibration level is larger than that from a lower one. However, with higher vibration levels, at a certain level the ionization probability will take maximum and decrease with next levels. (paper)

Non-traditional vibration mitigation methods for reciprocating compressor system

NARCIS (Netherlands)

Eijk, A.; Lange, T.J. de; Vreugd, J. de; Slis, E.J.P.

2016-01-01

Reciprocating compressors generate vibrations caused by pulsation-induced forces, mechanical (unbalanced) free forces and moments, crosshead guide forces and cylinder stretch forces. The traditional way of mitigating the vibration and cyclic stress levels to avoid fatigue failure of parts of the

Optical fiber grating vibration sensor for vibration monitoring of hydraulic pump

Science.gov (United States)

Zhang, Zhengyi; Liu, Chuntong; Li, Hongcai; He, Zhenxin; Zhao, Xiaofeng

2017-06-01

In view of the existing electrical vibration monitoring traditional hydraulic pump vibration sensor, the high false alarm rate is susceptible to electromagnetic interference and is not easy to achieve long-term reliable monitoring, based on the design of a beam of the uniform strength structure of the fiber Bragg grating (FBG) vibration sensor. In this paper, based on the analysis of the vibration theory of the equal strength beam, the principle of FBG vibration tuning based on the equal intensity beam is derived. According to the practical application of the project, the structural dimensions of the equal strength beam are determined, and the optimization design of the vibrator is carried out. The finite element analysis of the sensor is carried out by ANSYS, and the first order resonant frequency is 94.739 Hz. The vibration test of the sensor is carried out by using the vibration frequency of 35 Hz and the vibration source of 50 Hz. The time domain and frequency domain analysis results of test data show that the sensor has good dynamic response characteristics, which can realize the accurate monitoring of the vibration frequency and meet the special requirements of vibration monitoring of hydraulic pump under specific environment.

Investigation of Concrete Floor Vibration Using Heel-Drop Test

Science.gov (United States)

Azaman, N. A. Mohd; Ghafar, N. H. Abd; Azhar, A. F.; Fauzi, A. A.; Ismail, H. A.; Syed Idrus, S. S.; Mokhjar, S. S.; Hamid, F. F. Abd

2018-04-01

In recent years, there is an increased in floor vibration problems of structures like residential and commercial building. Vibration is defined as a serviceability issue related to the comfort of the occupant or damage equipment. Human activities are the main source of vibration in the building and it could affect the human comfort and annoyance of residents in the building when the vibration exceed the recommend level. A new building, Madrasah Tahfiz located at Yong Peng have vibration problem when load subjected on the first floor of the building. However, the limitation of vibration occurs on building is unknown. Therefore, testing is needed to determine the vibration behaviour (frequency, damping ratio and mode shape) of the building. Heel-drop with pace 2Hz was used in field measurement to obtain the vibration response. Since, the heel-drop test results would vary in light of person performance, test are carried out three time to reduce uncertainty. Natural frequency from Frequency Response Function analysis (FRF) is 17.4Hz, 16.8, 17.4Hz respectively for each test.

Vibrational quasi-continuum in unimolecular multiphoton dissociation

Energy Technology Data Exchange (ETDEWEB)

Garcia Fernandez, P.; Gonzalez-Diaz, P.F.

1987-04-01

The vibrational quasi-continuum of the boron trifluoride molecule has been qualitatively studied and the formalism extended to treat N-normal-mode molecules. The anharmonic potential curves for the BF/sub 3/ normal modes have been calculated, and the computed anharmonicity constants have been tested against the fundamental frequencies. The potential curve of the wagging mode has been simulated by an internal rotation of one of the fluoride atoms. The vibrational-energy levels and wave functions have been calculated applying second-order perturbation theory. The quasi-continuum energy levels of BF/sub 3/ have been obtained by means of a method based in forming adequate linear combinations of wave functions belonging to the N-1 modes resulting from removing the i.r.-active mode;the associated energies have been minimized using a constrained minimization procedure. It has been found that the energy pattern of the N-1 vibrational modes possesses an energy density high enough for constituting a vibrational heat bath and, finally, it has been verified that the ''fictitious'' pattern of the active mode is included in the pattern of the N-1 modes.

Tool-specific performance of vibration-reducing gloves for attenuating fingers-transmitted vibration

Science.gov (United States)

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

2016-01-01

BACKGROUND Fingers-transmitted vibration can cause vibration-induced white finger. The effectiveness of vibration-reducing (VR) gloves for reducing hand transmitted vibration to the fingers has not been sufficiently examined. OBJECTIVE The objective of this study is to examine tool-specific performance of VR gloves for reducing finger-transmitted vibrations in three orthogonal directions (3D) from powered hand tools. METHODS A transfer function method was used to estimate the tool-specific effectiveness of four typical VR gloves. The transfer functions of the VR glove fingers in three directions were either measured in this study or during a previous study using a 3D laser vibrometer. More than seventy vibration spectra of various tools or machines were used in the estimations. RESULTS When assessed based on frequency-weighted acceleration, the gloves provided little vibration reduction. In some cases, the gloves amplified the vibration by more than 10%, especially the neoprene glove. However, the neoprene glove did the best when the assessment was based on unweighted acceleration. The neoprene glove was able to reduce the vibration by 10% or more of the unweighted vibration for 27 out of the 79 tools. If the dominant vibration of a tool handle or workpiece was in the shear direction relative to the fingers, as observed in the operation of needle scalers, hammer chisels, and bucking bars, the gloves did not reduce the vibration but increased it. CONCLUSIONS This study confirmed that the effectiveness for reducing vibration varied with the gloves and the vibration reduction of each glove depended on tool, vibration direction to the fingers, and finger location. VR gloves, including certified anti-vibration gloves do not provide much vibration reduction when judged based on frequency-weighted acceleration. However, some of the VR gloves can provide more than 10% reduction of the unweighted vibration for some tools or workpieces. Tools and gloves can be matched for

Study of parameters of simultaneous lasing on two lines sharing an upper level

International Nuclear Information System (INIS)

Pikulev, A A

2002-01-01

Stationary lasing at two competing lines sharing an upper level is studied. Based on the expressions for the gain obtained earlier, the possible lasing regimes are considered (at one or two lines) and approximate formulas are derived for determining the output power in each line. These formulas are shown to be the generalisation of the Rigrod formula to the case of simultaneous lasing at several lines. (control of laser radiation parameters)

Flow-induced vibration -- 1994. PVP-Volume 273

International Nuclear Information System (INIS)

Au-Yang, M.K.; Fujita, K.

1994-01-01

Flow-induced vibration is a subject of practical interest to many engineering disciplines, including the power generation, process, and petrochemical industries. In the nuclear industry, flow-induced vibration reaches a higher level of concern because of safety issues and the huge cost associated with down time and site repair. Not surprisingly, during the last 25 years a tremendous amount of effort has been spent in the study of flow-induced vibration phenomena related to nuclear plant components, notably nuclear steam generator tube banks and nuclear fuel bundles. Yet, in spite of this concentrated effort, the industry is still not free from flow-induced vibration-related problems. This explains why in this volume almost half of the papers address the issue of cross-flow induced vibration in tube bundles, with applications to the nuclear steam generator and nuclear fuel bundles in mind. Unlike 10 or 15 years ago, when flow-induced vibration studies almost always involved experimentation and empirical studies, the advent of high-speed computers has enabled numerical calculation and simulation of this complex phenomenon to take place. Separate abstracts were prepared for 27 papers in this volume

Vibration test report on the instrumented capsule for fuel irradiation test

Energy Technology Data Exchange (ETDEWEB)

Ryu, Jeong Soo; Yoon, D. B.; Wu, J. S.; Oh, J. M.; Park, S. J.; Cho, M. S.; Kim, B. G.; Kang, Y. W

2003-01-01

The fluid-induced vibration level of instrumented capsule, which was manufactured for fuel irradiation test at the reactor core of HANARO, was investigated. For this purpose, the instrumented capsule was loaded at the OR site of the HANARO design verification test facility that could simulate identical flow condition as the HANARO core. Then, vibration signals of the instrumented capsule subjected to various flow conditions were measured by using vibration sensors. In time domain analysis, maximum amplitudes and RMS values of the measured acceleration and displacement signals were obtained. By using frequency domain analysis, frequency components of the fluid-induced vibration were analyzed. In addition, natural frequencies of the instrumented capsule were obtained by performing modal test. The frequency analysis results showed that the natural frequency components near 7.5Hz and 17.5Hz were dominant in the fluid-induced vibration signal. The maximum amplitude of the accelerations was measured as 12.04m/s{sup 2} that is within the allowable vibrational limit(18.99m/s{sup 2})of the reactor structure. Also, the maximum displacement amplitude was calculated as 0.191mm. Since these vibration levels are remarkably low, excessive vibration is not expected when the irradiation test of the instrumented capsule is performed at the HANARO core.

Vibration test report for in-chimney bracket and instrumented fuel assembly

Energy Technology Data Exchange (ETDEWEB)

Ryu, Jeong Soo; Yoon, D. B.; Cho, Y. G.; Ahn, G. H.; Lee, J. H.; Park, J.H

2000-10-01

The vibration levels of in-chimney bracket structure which is installed in reactor chimney and instrumented fuel assembly(Type-B Bundle) are investigated under the steady state normal operating condition of the reactor. For this purpose, 4 acceleration data on the guide tube of the instrumented fuel assembly and in-chimney bracket structures subjected to fluid induced vibration are measured. For the analysis of the vibration data, vibration analysis program which can perform basic time and frequency domain analysis, is prepared, and its reliability is verified by comparing the analysis results with those of commercial analysis program(I-DEAS). In time domain analysis, maximum amplitudes, and RMS values of accelerations and displacements from the measured vibration signal, are obtained. The frequency components of the vibration data are analyzed by using the frequency domain analysis. These analysis results show that the levels of the measured vibrations are within the allowable level, and the low frequency component near 10 Hz is dominant in the vibration signal. For the evaluation of the structural integrity on the in-chimney bracket and related structures including the instrumented fuel assembly, the static analysis for ANSYS finite element model is carried out. These analysis results show that the maximum stresses are within the allowable stresses of the ASME code, and the maximum displacement of the top of the flow tube is within the displacement limit. Therefore any damage on the structural integrity is not expected when the irradiation test is performed using the in-chimney bracket.

Vibration test report for in-chimney bracket and instrumented fuel assembly

International Nuclear Information System (INIS)

Ryu, Jeong Soo; Yoon, D. B.; Cho, Y. G.; Ahn, G. H.; Lee, J. H.; Park, J.H.

2000-10-01

The vibration levels of in-chimney bracket structure which is installed in reactor chimney and instrumented fuel assembly(Type-B Bundle) are investigated under the steady state normal operating condition of the reactor. For this purpose, 4 acceleration data on the guide tube of the instrumented fuel assembly and in-chimney bracket structures subjected to fluid induced vibration are measured. For the analysis of the vibration data, vibration analysis program which can perform basic time and frequency domain analysis, is prepared, and its reliability is verified by comparing the analysis results with those of commercial analysis program(I-DEAS). In time domain analysis, maximum amplitudes, and RMS values of accelerations and displacements from the measured vibration signal, are obtained. The frequency components of the vibration data are analyzed by using the frequency domain analysis. These analysis results show that the levels of the measured vibrations are within the allowable level, and the low frequency component near 10 Hz is dominant in the vibration signal. For the evaluation of the structural integrity on the in-chimney bracket and related structures including the instrumented fuel assembly, the static analysis for ANSYS finite element model is carried out. These analysis results show that the maximum stresses are within the allowable stresses of the ASME code, and the maximum displacement of the top of the flow tube is within the displacement limit. Therefore any damage on the structural integrity is not expected when the irradiation test is performed using the in-chimney bracket

Blasting vibrations control: The shortcomings of traditional methods

Energy Technology Data Exchange (ETDEWEB)

Vuillaume, P.M.; Kiszlo, M. [Institut National de l`Environnement Industriel et des Risques, Verneuil en Halatte (France); Bernard, T. [Compagnie Nouvelle de Scientifiques, Nice (France)

1996-12-31

In the context of its studies for the French ministry of the environment and for the French national coal board, INERIS (the French institute for the industrial environment and hazards, formerly CERCHAR) has made a complete critical survey of the methods generally used to reduce the levels of blasting vibrations. It is generally acknowledged that the main parameter to control vibrations is the so-called instantaneous charge, or charge per delay. This should be reduced as much as possible in order to diminish vibration levels. On account of this, the use of a new generation of blasting devices, such as non-electric detonators or electronic sequential timers has been developed since the seventies. INERIS has collected data from about 900 blasts in 2 quarries and 3 open pit mines. These data include input parameters such as borehole diameter, burden, spacing, charge per hole, charge per delay, total fired charge, etc ... They also include output measurements, such as vibration peak particle velocities, and main frequencies. These data have been analyzed with the help of multi variable statistical tools. Blasting tests were undertaken to evaluate new methods of vibrations control, such as the superposition of vibration signals. These methods appear to be accurate in many critical cases, but certainly would be highly improved with a better accuracy of firing delays. The development of electronic detonators seems to be the way of the future for a better blasting control.

Theory of vibration protection

CERN Document Server

Karnovsky, Igor A

2016-01-01

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

Vibration of machine

International Nuclear Information System (INIS)

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

2001-09-01

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

Sensitivity of Footbridge Vibrations to Stochastic Walking Parameters

DEFF Research Database (Denmark)

Pedersen, Lars; Frier, Christian

2010-01-01

of the pedestrian. A stochastic modelling approach is adopted for this paper and it facilitates quantifying the probability of exceeding various vibration levels, which is useful in a discussion of serviceability of a footbridge design. However, estimates of statistical distributions of footbridge vibration levels...... to walking loads might be influenced by the models assumed for the parameters of the load model (the walking parameters). The paper explores how sensitive estimates of the statistical distribution of vertical footbridge response are to various stochastic assumptions for the walking parameters. The basis...... for the study is a literature review identifying different suggestions as to how the stochastic nature of these parameters may be modelled, and a parameter study examines how the different models influence estimates of the statistical distribution of footbridge vibrations. By neglecting scatter in some...

Acute Whole Body Vibration Decreases the Glucose Levels in Elderly Diabetic Women

Directory of Open Access Journals (Sweden)

Maíra Florentino Pessoa

2018-01-01

Full Text Available Type II diabetes (TIIDM is characterized by high levels of blood glucose followed by excessive insulin release so that the target cells become less sensitive, developing insulin resistance and maintaining hyperglycemic levels. Physical activity is the strongest element to prevent and to manage the TIIDM, and the majority of patients do not remain in regularly active levels, because the premature fatigue in these patients decreases the adherence to the training. Contrastingly, the whole body vibration (WBV training may improve the glucose metabolism in diabetic patients, reducing the peripheral blood sugar, decreasing the physical discomfort and perceived exertion. Therefore, the purpose of the study was to determine the effect of an acute WBV session as therapy to promote fasting decreases in insulin levels in peripheral blood in TIIDM when compared to healthy elderly. For this, fifteen healthy elderly women and fourteen diabetic elderly women, all sedentary, were allocated in diabetic or control groups, and we made an acute whole body session composed of 10 bouts lasting 2 minutes each one, separated by a 30-second rest period. The WBV was executed in a triaxial platform MY3 Power Plate® at 35 hertz and has been chosen a peak-to-peak displacement of 4 millimeters. After the protocol, both groups decreased the glycemic levels and increased lactate production in relation to the basal levels and when compared diabetic and control, where the most important results have been shown in diabetic women. This study revealed that WBV training in TIIDM has had significant beneficial effects on the control of glucose levels, still in an acute session. So that, the complete training probably will show better results about glycemic control and this finding could be especially important when prescribing exercise for elderly who are unable or unwilling to use traditional loads or who show poor exercise compliance.

IUPAC critical evaluation of the rotational–vibrational spectra of water vapor, Part III: Energy levels and transition wavenumbers for H216O

International Nuclear Information System (INIS)

Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Császár, Attila G.; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.; Al Derzi, Afaf R.; Fábri, Csaba; Fazliev, Alexander Z.; Furtenbacher, Tibor

2013-01-01

This is the third of a series of articles reporting critically evaluated rotational–vibrational line positions, transition intensities, and energy levels, with associated critically reviewed labels and uncertainties, for all the main isotopologues of water. This paper presents experimental line positions, experimental-quality energy levels, and validated labels for rotational–vibrational transitions of the most abundant isotopologue of water, H 2 16 O. The latest version of the MARVEL (Measured Active Rotational–Vibrational Energy Levels) line-inversion procedure is used to determine the rovibrational energy levels of the electronic ground state of H 2 16 O from experimentally measured lines, together with their self-consistent uncertainties, for the spectral region up to the first dissociation limit. The spectroscopic network of H 2 16 O containstwo components, an ortho (o) and a para (p) one. For o-H 2 16 O and p-H 2 16 O, experimentally measured, assigned, and labeled transitions were analyzed from more than 100 sources. The measured lines come from one-photon spectra recorded at room temperature in absorption, from hot samples with temperatures up to 3000 K recorded in emission, and from multiresonance excitation spectra which sample levels up to dissociation. The total number of transitions considered is 184 667 of which 182 156 are validated: 68 027 between para states and 114 129 ortho ones. These transitions give rise to 18 486 validated energy levels, of which 10 446 and 8040 belong to o-H 2 16 O and p-H 2 16 O, respectively. The energy levels, including their labeling with approximate normal-mode and rigid-rotor quantum numbers, have been checked against ones determined from accurate variational nuclear motion computations employing exact kinetic energy operators as well as against previous compilations of energy levels. The extensive list of MARVEL lines and levels obtained are deposited in the supplementary data of this paper, as well as in a

Heterodyne Angle Deviation Interferometry in Vibration and Bubble Measurements

OpenAIRE

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

2016-01-01

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

Review of Energy Harvesters Utilizing Bridge Vibrations

Directory of Open Access Journals (Sweden)

Farid Ullah Khan

2016-01-01

Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.

Investigation and analysis the vibration of handles of chainsaw without cutting

Directory of Open Access Journals (Sweden)

M Feyzi

2016-04-01

Full Text Available Introduction: Nowadays most of the agricultural and industrial tasks are performed using different machines and almost any people are exposed to the vibration of these machines. Just as sound can be either music to the ear or irritating noise, human vibrations can either be pleasant or unpleasant. Whole-body vibration and hand-arm vibration are two main types of unpleasant vibration. The hand-arm transmitted vibration can cause complex vascular, neurological and musculoskeletal disorder, collectively named as hand-arm vibration syndrome. The chainsaw is a portable machine, powered by a two-stroke engine. This machine is used by tree surgeons to fell trees, remove branches, and other activities such as prune trees. The chainsaw exposes own operators to high level of hand-arm vibration which can lead to problems such as vibration white finger syndrome and Raynaud's phenomenon. White finger syndrome affects the nerves, blood vessels, muscles, and joints of the hand, wrist and arm. It is clear that before trying to control the vibrations, the level of vibrations should be identified. Therefore, an investigation on the vibration level of this machine is crucial. Materials and Methods: The Stihl-MS230 chainsaw was selected in this study. The size of this type of chainsaw is middle and it is equipped with anti-vibration system. According to the ISO-7505 standard, vibration must be measured at three speed level of engine. First at idling speed, second at nominal speed and third at 133% of the nominal speed or maximum speed of engine whichever is less (Racing. So 2800, 10000, and 13300 RPM Engine speed were selected. One of the employed accessories was ARMA ETI-TACHO tachometer which had been fabricated in Taiwan. The vibrations were measured and analyzed using the portable data acquisition system (Easy Viber. During the measurements, data acquisition system was powered by internal batteries. The vibrations were sensed by the piezoelectric accelerometer

Student Perceived and Determined Knowledge of Biology Concepts in an Upper-Level Biology Course

Science.gov (United States)

Montplaisir, Lisa

2014-01-01

Students who lack metacognitive skills can struggle with the learning process. To be effective learners, students should recognize what they know and what they do not know. This study examines the relationship between students’ perception of their knowledge and determined knowledge in an upper-level biology course utilizing a pre/posttest approach. Significant differences in students’ perception of their knowledge and their determined knowledge exist at the beginning (pretest) and end (posttest) of the course. Alignment between student perception and determined knowledge was significantly more accurate on the posttest compared with the pretest. Students whose determined knowledge was in the upper quartile had significantly better alignment between their perception and determined knowledge on the pre- and posttest than students in the lower quartile. No difference exists between how students perceived their knowledge between upper- and lower-quartile students. There was a significant difference in alignment of perception and determined knowledge between males and females on the posttest, with females being more accurate in their perception of knowledge. This study provides evidence of discrepancies that exist between what students perceive they know and what they actually know. PMID:26086662

Numerical simulation of 900 MW control rods impact friction vibration and wear

International Nuclear Information System (INIS)

Jacquart, G.

1993-12-01

Impact-friction vibrations and wear have motivated a great research and development program aiming at understanding the impact and vibration behaviour of these components through experimental and numerical works. This report presents a numerical simulation of the vibrations of a single control rod and of a whole control cluster. Excitation sources for this component are due to hydraulic forces and are situated in the lower part of the rods and in the part of the cluster. Some parametric computations have been carried out on a single rod, to evaluate the effect of the lower excitation source. Different excitation levels, different eccentricities or static forces have been computed and compared to measurements on the MAGALY mock-up representing a complete rod cluster. A numerical model for the complete cluster allowed the evaluation of the upper excitation source effects. This source appears to be less powerful than the lower one. These results have been validated by comparison with MAGALY measurements. At last, some computations were performed with a model of the complete cluster, taking into account the both excitation sources. A parametric study on eccentricity and static forces has been carried out. A comparison with MAGALY measurements seems to be fairly fitting, showing that the numerical results are of the right order of magnitude. Through this numerical study, we have shown that numerical simulation of a complete control rod cluster could be lead, and we have obtained some new informations about impact forces and wear rates that need to be confirmed by more computational or experimental works or in-situ measurements. (author). 10 annexes, 11 refs

Non-LTE models of Titan's upper atmosphere

Science.gov (United States)

Yelle, Roger V.

1991-01-01

Models for the thermal structure of Titan's upper atmosphere, between 0.1 mbar and 0.01 nbar are presented. The calculations include non-LTE heating/cooling in the rotation-vibration bands of CH4, C2H2, and C2H6, absorption of solar IR radiation in the near-IR bands of CH4 and subsequent cascading to the nu-4 band of CH4, absorption of solar EUV and UV radiation, thermal conduction and cooling by HCN rotational lines. Unlike earlier models, the calculated exospheric temperature agrees well with observations, because of the importance of HCN cooling. The calculations predict a well-developed mesopause with a temperature of 135-140 K at an altitude of approximately 600 km and pressure of about 0.1 microbar. The mesopause is at a higher pressure than predicted by earlier calculations because non-LTE radiative transfer in the rotation-vibration bands of CH4, C2H2, and C2H6 is treated in an accurate manner. The accuracy of the LTE approximation for source functions and heating rates is discussed.

Particular aspects regarding the effects of whole body vibration exposure

Directory of Open Access Journals (Sweden)

Picu Mihaela

2018-01-01

Full Text Available This paper analyses the influence of whole-body vibrations on human performance; for this it was investigated how a group of men (20-29 years of age and a group of woman (21–31 years of age answered to specific requirements after being subjected to vertical vibrations under controlled laboratory conditions for 10-25 min. The vibrations were generated by a vibrant system with known amplitudes and frequencies. Accelerations were measured with NetdB - complex system for measuring and analysing human vibration and they were found in the range 0.4 - 3.1m/s2. The subjects’ performances were determined for each vibration level using specific tests. It can be concluded that exposure to vibrations higher than those recommended by ISO 2631 significantly disrupts how subjects responded to tests requirements.

Comparative Study of Reducing the Vibration Level of a Cylindrical Gear Transmissions by Increasing the Manufacturing Precision of the Gears, Respective by Applying of Fluoropolymer Coating on the Gear Teeth

Directory of Open Access Journals (Sweden)

Zoltan Korka

2012-09-01

Full Text Available The current trend in the construction of gearboxes, regarding the speed increase, favors the increase of the dynamic loads and, consequentially of the vibration level. Therefore, the vibration reduction of gear transmissions finds a growing interest, representing an element of fight against environmental pollution.

Effect of structural design on traffic-induced building vibrations

DEFF Research Database (Denmark)

Persson, Peter; Andersen, Lars Vabbersgaard; Persson, Kent

2017-01-01

Population growth and urbanization results in densified cities, where new buildings are being built closer to existing vibration sources such as road-, tram- and rail traffic. In addition, new transportation systems are constructed closer to existing buildings. Potential disturbing vibrations...... are one issue to consider in planning urban environment and densification of cities. Vibrations can be disturbing for humans but also for sensitive equipment in, for example, hospitals. In determining the risk for disturbing vibrations, the distance between the source and the receiver, the ground...... properties, and type and size of the building are governing factors. In the paper, a study is presented aiming at investigating the influence of various parameters of the building's structural design on vibration levels in the structure caused by ground surface loads, e.g. traffic. Parameters studied...

Vibrationally coupled electron transport through single-molecule junctions

Energy Technology Data Exchange (ETDEWEB)

Haertle, Rainer

2012-04-26

vibrational effects have a profound influence on the transport characteristics of a single-molecule contact and play therefore a fundamental role in this transport problem. Our findings demonstrate that vibrationally coupled electron transport through a molecular junction involves two types of processes: (i) transport processes, where an electron tunnels through the molecular bridge from one lead to the other, and (ii) electron-hole pair creation processes, where an electron tunnels from one of the leads onto the molecular bridge and back to the same lead again. Transport processes directly contribute to the electrical current flowing through a molecular contact and involve both excitation and deexcitation processes of the vibrational modes of the junction. Electron-hole pair creation processes do not directly contribute to the electrical current and typically involve only deexcitation processes. Nevertheless, they constitute a cooling mechanism for the vibrational modes of a single-molecule junction that is as important as cooling by transport processes. As the level of vibrational excitation determines the efficiency of electron transport processes, they have an indirect influence on the electrical current flowing through the junction. As we show, however, this influence can be substantial, in particular, if the molecule is coupled asymmetrically to the leads. Accounting for all these processes and their complex interrelationship, we analyze a number of intriguing transport phenomena, including rectification, negative differential resistance, anomalous peak broadening, mode-selective vibrational excitation and vibrationally induced decoherence. Moreover, we show that higher levels of vibrational excitation are obtained for weaker electronic-vibrational coupling. Thus, based on physical grounds, we establish a relation between the weak electronic-vibrational coupling limit and the limit of large bias voltages, where the level of vibrational excitation in a molecular junction

REDUCING THE LOAD OF THE ELASTIC SUPPORT OF THE RESONANCE VIBRATING CONVEYOR MACHINES

Directory of Open Access Journals (Sweden)

A. I. Afanas'ev

2018-03-01

Full Text Available The relevance of the work is conditioned by the necessity of improving the efficiency of vibrator machines. This is done by means of increasing the reliability of the elastic reference elements. The purpose of the work is to develop a dynamic resonance system of the vibrator machine with a reduced mass of the working body and loads on elastic supports. The resonance vibrator machines appeared in the USSR in the mid-twentieth century. They were used in the coal industry. The machines of foreign production and some of the domestic machines are now produced according to the balanced scheme. Domestic machines of the "PEV" series are made according to the vibro-isolated scheme, and the vibro-exciter is rigidly connected to the box. The resonant oscillation frequency of these machines is 50 Hz, and the maximum acceleration is significantly greater than the one of free fall. These resonant machines operate with the amplitude up to 2.2 mm and they have a ratio mode greater than unity. The practice of running these machines shows their relatively low efficiency when screening thin products. The common disadvantage of unbalanced resonance vibrator machines is a relatively large loading of elastic elements (supports and the presence of a massive frame. The disadvantage of the balanced ones is the reactive mass or several working bodies with the same mass. One of the ways to achieve the goal is to define a rational dynamic scheme of the resonance vibrator machines. The results and their application. The authors proposed to transform a traditional one-mass oscillatory system into a system equivalent to a dynamic vibration dampener. This system can significantly reduce the weight of the machine. It can reduce the rigidity and loading of the elastic supports at a given frequency of oscillations. The upper mass can be reduced by 2 or 3 times, and the lower mass can be several times smaller than the upper one. At the same time, the dynamic loads on the supports

Spectroscopic parameters, vibrational levels, transition dipole moments and transition probabilities of the 9 low-lying states of the NCl+ cation

Science.gov (United States)

Yin, Yuan; Shi, Deheng; Sun, Jinfeng; Zhu, Zunlue

2018-03-01

This work calculates the potential energy curves of 9 Λ-S and 28 Ω states of the NCl+ cation. The technique employed is the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction. The Λ-S states are X2Π, 12Σ+, 14Π, 14Σ+, 14Σ-, 24Π, 14Δ, 16Σ+, and 16Π, which are yielded from the first two dissociation channels of NCl+ cation. The Ω states are generated from these Λ-S states. The 14Π, 14Δ, 16Σ+, and 16Π states are inverted with the spin-orbit coupling effect included. The 14Σ+, 16Σ+, and 16Π states are very weakly bound, whose well depths are only several-hundred cm- 1. One avoided crossing of PECs occurs between the 12Σ+ and 22Σ+ states. To improve the quality of potential energy curves, core-valence correlation and scalar relativistic corrections are included. The potential energies are extrapolated to the complete basis set limit. The spectroscopic parameters and vibrational levels are calculated. The transition dipole moments are computed. The Franck-Condon factors, Einstein coefficients, and radiative lifetimes of many transitions are determined. The spectroscopic approaches are proposed for observing these states according to the transition probabilities. The spin-orbit coupling effect on the spectroscopic and vibrational properties is evaluated. The spectroscopic parameters, vibrational levels, transition dipole moments, as well as transition probabilities reported in this paper could be considered to be very reliable.

Flow Induced Vibration Program at Argonne National Laboratory

International Nuclear Information System (INIS)

1984-01-01

Argonne National Laboratory has had a Flow Induced Vibration Program since 1967; the Program currently resides in the Laboratory's Components Technology Division. Throughout its existence, the overall objective of the program has been to develop and apply new and/or improved methods of analysis and testing for the design evaluation of nuclear reactor plant components and heat exchange equipment from the standpoint of flow induced vibration. Historically, the majority of the program activities have been funded by the US Atomic Energy Commission (AEC), Energy Research and Development Administration (ERDA), and Department of Energy (DOE). Current DOE funding is from the Breeder Mechanical Component Development Division, Office of Breeder Technology Projects; Energy Conversion and Utilization Technology (ECUT) Program, Office of Energy Systems Research; and Division of Engineering, Mathematical and Geosciences, Office of Basic Energy Sciences. Testing of Clinch River Breeder Reactor upper plenum components has been funded by the Clinch River Breeder Reactor Plant (CRBRP) Project Office. Work has also been performed under contract with Foster Wheeler, General Electric, Duke Power Company, US Nuclear Regulatory Commission, and Westinghouse

Parametric analysis of protective grid flow induced vibration

Energy Technology Data Exchange (ETDEWEB)

Ryu, Jooyoung; Eom, Kyongbo; Jeon, Sangyoun; Suh, Jungmin [KEPCO NF Co., Daejeon (Korea, Republic of)

2012-10-15

Protective grid (P-grid) flow-induced vibration in a nuclear power reactor is one of the critical factors for the mechanical integrity of a nuclear fuel. The P-grid is located at the lower most position above the bottom nozzle of the nuclear fuel as shown in Fig. 1, and it is required for not only filtering debris, but also supporting fuel rods. On the other hand, P-grid working conditions installed in a nuclear fuel in a reactor are severe in terms of flow speed, temperature and pressure. Considering such a severe condition of P-grid's functional performance in working environment, excessive vibration could be developed. Furthermore, if the P-grid is exposed to high levels of excessive vibration over a long period of time, fatigue failure could be unavoidable. Therefore, it is important to reduce excessive vibration while maintaining P-grid's own functional performance. KEPCO Nuclear Fuel has developed a test facility - Investigation Flow-induced Vibration (INFINIT) - to study flow-induced vibration caused by flowing coolant at various flow rates. To investigate specific relationships between configuration of P-grid and flow-induced vibration characteristics, several types of the P-grids were tested in INFINIT facility. And, based on the test results through parametric studies, the flow-induced vibration characteristics could be analyzed, and critical design parameters were found.

Nonsynchronous vibrations observed in a supercritical power transmission shaft

Science.gov (United States)

Darlow, M. S.; Zorzi, E. S.

1979-01-01

A flexible shaft is prone to a number of vibration phenomena which occur at frequencies other than synchronous with rotational speed. Nonsynchronous vibrations from several sources were observed while running a test rig designed to simulate the operation of a supercritical power transmission shaft. The test rig was run first with very light external damping and then with a higher level of external damping, for comparison. As a result, the effect of external damping on the nonsynchronous vibrations of the test rig was observed. All of these nonsynchronous vibrations were of significant amplitude. Their presence in the vibrations spectra for a supercritical power transmission shaft at various speeds in the operating range indicates that very careful attention to all of the vibration spectra should be made in any supercritical power transmission shafting. This paper presents a review of the analysis performed and a comparison with experimental data. A thorough discussion of the observed nonsynchronous whirl is also provided.

Experimental Research on Vibrations of Double Harmonic Gear Transmission

Directory of Open Access Journals (Sweden)

Sava Ianici

2017-11-01

Full Text Available Gears transmission can be important sources of vibration in the mechanical system structures and can have a significant share in the overall vibration level. The current trend of significant increase in powers and speeds transmitted by modern mechanical systems, along with the size reduction, may cause a worsening of the behaviour of transmissions with gears in terms of vibration, especially when the optimization criteria were not respected in the design, execution and installation phase. This paper presents a study of vibrations that occur in a double harmonic gear transmission (DHGT, based on experimental research. The experimental researches revealed that in a double harmonic gear transmission the vibrations are initiated and develop in the multipara harmonics engagement of the teeth and in the kinematic couplings materialized between the wave generator and the flexible toothed wheel. These vibrations are later transmitted by means of the shafts and bearings to the transmission housing, respectively, through the walls of it, propagating in the air.

Anti-vibration gloves?

Science.gov (United States)

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

2015-03-01

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

Dynamic Properties of the Painter Street Overpass at Different Levels of Vibration

DEFF Research Database (Denmark)

Ventura, C. E.; Brincker, Rune; Andersen, P.

2005-01-01

This paper describes the results from a series of ambient vibration studies conducted on the Painter Street Overpass in Rio Dell, California. Painter Street is a two-span, skewed reinforced concrete bridge with two single piers near the middle and monolithic abutments, typical of bridge overpasses...... from analyses of selected strong motion records. The magnitude of the events investigated ranges from ML=4.4 to ML=6.9, which produced accelerations of up to 0.54g at the free field site, 1.3g at the abutments, and 0.86g on the deck. The results of this study indicate that the overall dynamic...... properties of the bridge are very sensitive to the level of ground shaking and that soil-structure interaction is very important for this type structural system. Although the superstructure exhibited a nearly elastic response, the motions at the abutments and base of piers were significantly different...

Finite Element Analysis and Experimental Study on Elbow Vibration Transmission Characteristics

Science.gov (United States)

Qing-shan, Dai; Zhen-hai, Zhang; Shi-jian, Zhu

2017-11-01

Pipeline system vibration is one of the significant factors leading to the vibration and noise of vessel. Elbow is widely used in the pipeline system. However, the researches about vibration of elbow are little, and there is no systematic study. In this research, we firstly analysed the relationship between elbow vibration transmission characteristics and bending radius by ABAQUS finite element simulation. Then, we conducted the further vibration test to observe the vibration transmission characteristics of different elbows which have the same diameter and different bending radius under different flow velocity. The results of simulation calculation and experiment both showed that the vibration acceleration levels of the pipeline system decreased with the increase of bending radius of the elbow, which was beneficial to reduce the transmission of vibration in the pipeline system. The results could be used as reference for further studies and designs for the low noise installation of pipeline system.

Pathogenic and clinical aspects of polyneuropathies, with reference to the hand-arm vibration syndrome.

Science.gov (United States)

Juntunen, J; Taskinen, H

1987-08-01

Along with attacks of white finger, symptoms suggesting peripheral sensorimotor neuropathy, ie, polyneuropathy or entrapment neuropathy, are very important in the hand-arm vibration syndrome. Peripheral neuropathies are probably associated with the occurrence of the syndrome because of a selection mechanism. Polyneuropathy may be a contributing factor in the development of entrapment neuropathies in the upper extremities. It has multiple pathogenic mechanisms and numerous causative factors. However, peripheral nerves can react to pathological stimuli in a limited number of ways. Wallerian degeneration, segmental demyelination, and axonal degeneration are the classical neuropathological types of peripheral neuropathies, of which the first two are possible direct consequences of vibration exposure. The clinical manifestations of polyneuropathy range from sensory to motor types, sometimes with autonomic involvement. Whenever polyneuropathy is encountered in the hand-arm vibration syndrome, its etiologic possibilities should be considered. Regardless of the variable criteria used by different authors, individual diagnosis of the syndrome is always a probability diagnosis, and adequate neurological differential diagnostics have to be employed.

The Advanced Labs Website: resources for upper-level laboratories

Science.gov (United States)

Torres-Isea, Ramon

2012-03-01

The Advanced Labs web resource collection is an effort to create a central, comprehensive information base for college/university faculty who teach upper-level undergraduate laboratories. The website is produced by the American Association of Physics Teachers (AAPT). It is a part of ComPADRE, the online collection of resources in physics and astronomy education, which itself is a part of the National Science Foundation-funded National Science Digital Library (NSDL). After a brief review of its history, we will discuss the current status of the website while describing the various types of resources available at the site and presenting examples of each. We will detail a step-by-step procedure for submitting resources to the website. The resource collection is designed to be a community effort and thus welcomes input and contributions from its users. We will also present plans, and will seek audience feedback, for additional website services and features. The constraints, roadblocks, and rewards of this project will also be addressed.

Concorde noise-induced building vibrations: International Airport Dulles. [studies by Langley Research Center

Science.gov (United States)

Mayes, W. H.; Scholl, H. F.; Stephens, D. G.; Holliday, B. G.; Deloach, R.; Finley, T. D.; Holmes, H. K.; Lewis, R. B.; Lynch, J. W.

1977-01-01

A series of studies were conducted to assess the noise-induced building vibrations associated with Concorde operations. The vibration levels of windows, walls, and floors were measured along with the associated noise levels of Concorde, subsonic aircraft and some nonaircraft events. Test sites included Sully Plantation which is adjacent to Dulles International Airport and three residential homes located in Montgomery County, Maryland. The measured vibration response levels due to Concorde operations were found to be: (1) higher than the levels due to other aircraft, (2) less than the levels due to certain household events which involve direct impulsive loading such as door and window closing, (3) less than criteria levels for building damage, and (4) comparable to levels which are perceptible to people.

Horizontal vibration suppression method suitable for super-high-speed elevators; Chokosoku elevator ni tekishita kago yokoshindo yokusei hoshiki

Energy Technology Data Exchange (ETDEWEB)

Muto, N. [Hitachi, Ltd., Tokyo (Japan); Kagomiya, K.; Kurosawa, T.; Konya, M> ; Ando, T. [Hitachi Building System Co. Ltd., Tokyo (Japan)

1998-03-01

Horizontal vibrations of elevator cars mainly occur because a car swings as roller guides installed at corners of a car frame move on a winding guide rail at high speeds. Rider comfort in high speed elevators is worsened by these vibrations. Conventional active dampers suppressing horizontal vibrations using ac servo motors make cars heavier so driving power becomes larger, and they are not easily applied to existing elevators. An active damping control method suited to super-high-speed elevators is which can solve these problems. The method suppresses vibrations by generating only enough magnetic force needed to suppress them only when vibrations of the car franc are produced. The vibrations are detected using acceleration detectors and magnets installed on left and right sides of the car frame. A computer simulator was made to analyze phenomena of car vibrations and to verify effects of the proposed magnetic damping controller. It was found that the vibrations generated on the cabin floor were remarkably large when left and right sides at the upper and lower parts of the car frame were swung by sine waves with the same phase. The vibrations bad two resonant modes. Results obtained with the computer simulator and a full scale running simulator showed that the acceleration on the cabin floor, even at the resonant frequencies, could be reduced by the magnetic damping control to around 0.1m/s{sup 2} which would provide a comfortable ride. 10 refs., 14 figs.

Force Limited Vibration Test of HESSI Imager

Science.gov (United States)

Amato, Deborah; Pankow, David; Thomsen, Knud

2000-01-01

The High Energy Solar Spectroscopic Imager (HESSI) is a solar x-ray and gamma-ray observatory scheduled for launch in November 2000. Vibration testing of the HESSI imager flight unit was performed in August 1999. The HESSI imager consists of a composite metering tube, two aluminum trays mounted to the tube on titanium flexure mounts, and nine modulation grids mounted on each tray. The vibration tests were acceleration controlled and force limited, in order to prevent overtesting. The force limited strategy reduced the shaker force and notched the acceleration at resonances. The test set-up, test levels, and results are presented. The development of the force limits is also discussed. The imager successfully survived the vibration testing.

Three-dimensional motion tracking correlates with skill level in upper gastrointestinal endoscopy

DEFF Research Database (Denmark)

Arnold, Sif H.; Svendsen, Morten Bo Søndergaard; Konge, Lars

2015-01-01

untrained medical students) were tested using a virtual reality simulator. A motion sensor was used to collect data regarding the distance between the hands, and height and movement of the scope hand. Test characteristics between groups were explored using Kruskal-Wallis H and Man-Whitney U exact tests......Background and study aim: Feedback is an essential part of training in upper gastrointestinal endoscopy. Virtual reality simulators provide limited feedback, focusing only on visual recognition with no feedback on the procedural part of training. Motion tracking identifies patterns of movement......, and this study aimed to explore the correlation between skill level and operator movement using an objective automated tool. Methods: In this medical education study, 37 operators (12 senior doctors who performed endoscopic retrograde cholangiopancreatography, 13 doctors with varying levels of experience, and 12...

Ultra-low-vibration pulse-tube cryocooler system - cooling capacity and vibration

Science.gov (United States)

Ikushima, Yuki; Li, Rui; Tomaru, Takayuki; Sato, Nobuaki; Suzuki, Toshikazu; Haruyama, Tomiyoshi; Shintomi, Takakazu; Yamamoto, Akira

2008-09-01

This report describes the development of low-vibration cooling systems with pulse-tube (PT) cryocoolers. Generally, PT cryocoolers have the advantage of lower vibrations in comparison to those of GM cryocoolers. However, cooling systems for the cryogenic laser interferometer observatory (CLIO), which is a gravitational wave detector, require an operational vibration that is sufficiently lower than that of a commercial PT cryocooler. The required specification for the vibration amplitude in cold stages is less than ±1 μm. Therefore, during the development of low-vibration cooling systems for the CLIO, we introduced advanced countermeasures for commercial PT cryocoolers. The cooling performance and the vibration amplitude were evaluated. The results revealed that 4 K and 80 K PT cooling systems with a vibration amplitude of less than ±1 μm and cooling performance of 4.5 K and 70 K at heat loads of 0.5 W and 50 W, respectively, were developed successfully.

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.)

Vibration analysis of the synchronous motor of a propane compressor

Energy Technology Data Exchange (ETDEWEB)

Nogueira, D.; Rangel Junior, J. de S. [Petroleo Brasileiro S.A. - PETROBRAS, Rio de Janeiro, RJ (Brazil)], Emails: diananogueira@petrobras.com.br, joilson_jr@petrobras.com.br; Moreira, R.G. [Petroleo Brasileiro S.A. - PETROBRAS, Cabiunas, RJ (Brazil)], E-mail: ricgmoreira@petrobras.com.br

2010-07-01

This paper aims at describing the Analysis of a synchronous electric motor which presented high vibration levels (shaft displacement and bearing housing vibration) during the commissioning process, as well as propose the best practices for the solution of vibration problems in similar situations. This motor belongs to the propane centrifugal compressor installed at a Gas Compression Station. The methodology used in this study conducted an investigation of the problems presented in the motor through the execution of many types of tests and the analysis of the results. The main evaluations were performed, such as the vibration analysis and the rotor dynamic analysis. The electric motor was shipped back to the manufacturer's shop, where the manufacturer made certain modifications to the motor structure so as to improve the structure stiffness, such as the improvement of the support and the increase of the thickness of the structural plates. In addition to that, the dynamic balancing of the rotating set was checked. Finally, the excitation at a critical speed close to the rated speed was found after Rotor Dynamics Analysis was performed again, because of the increase in bearing clearances. The bearing shells were replaced so as to increase the separation margin between these frequencies. In order to verify the final condition of the motor, the manufacturer repeated the standard tests - FAT (Factory Acceptance Tests) - according to internal procedure and international standards. As a result of this work, it was possible to conclude that there was a significant increase in the vibration levels due to unbalance conditions. It was also possible to conclude that there are close relationships between high vibration levels and unbalance conditions, as well as between high vibration levels and the stiffness of the system and its support. Certain points of attention related to the manufacturing process of the motor compressor are described at the end of this paper, based

The Relationship Between Air Particulate Levels and Upper Respiratory Disease in Soldiers Deployed to Bosnia (1997-1998)

National Research Council Canada - National Science Library

Hastings, Deborah

2001-01-01

This study had three objectives: to determine if there is a relationship between air particulate levels and upper respiratory disease in soldiers deployed to Bosnia between 1997-98, to establish a method for linking environmental...

Vibration characteristics of a long flexible rod supported with multiple gaps

International Nuclear Information System (INIS)

Umeda, Kenji; Ban, Minoru; Ito, Tomohiro; Nakamura, Tomoichi; Fujita, Katuhisa.

1991-01-01

Control rods are long flexible rods supported with multiple gaps and forced to vibrate by hydraulic forces of reactor coolant flow. In order to find methods, to extend control rod life time, flow-induced vibration and wear mechanism of control rod should be identified. As a basic approach for this objective a vibration test in air using a single control rod and nonlinear vibration analyses were conducted to study characteristic of vibration and wear at support points of the control rod. Several test and analytical cases were performed with several initial support conditions, exciting points and exciting force level. With these test results, some information on the vibration and wear mechanism of control rods that explain wear features in actual plants was obtained. (author)

a Method for Preview Vibration Control of Systems Having Forcing Inputs and Rapidly-Switched Dampers

Science.gov (United States)

ElBeheiry, E. M.

1998-07-01

In a variety of applications, especially in large scale dynamic systems, the mechanization of different vibration control elements in different locations would be decided by limitations placed on the modal vibration of the system and the inherent dynamic coupling between its modes. Also, the quality of vibration control to the economy of producing the whole system would be another trade-off leading to a mix of passive, active and semi-active vibration control elements in one system. This termactiveis limited to externally powered vibration control inputs and the termsemi-activeis limited to rapidly switched dampers. In this article, an optimal preview control method is developed for application to dynamic systems having active and semi-active vibration control elements mechanized at different locations in one system. The system is then a piecewise (bilinear) controller in which two independent sets of control inputs appear additively and multiplicatively. Calculus of variations along with the Hamiltonian approach are employed for the derivation of this method. In essence, it requires the active elements to be ideal force generators and the switched dampers to have the property of on-line variation of the damping characteristics to pre-determined limits. As the dampers switch during operation the whole system's structure differs, and then values of the active forcing inputs are adapted to match these rapid changes. Strictly speaking, each rapidly switched damper has pre-known upper and lower damping levels and it can take on any in-between value. This in-between value is to be determined by the method as long as the damper tracks a pre-known fully active control demand. In every damping state of each semi-active damper the method provides the optimal matching values of the active forcing inputs. The method is shown to have the feature of solving simple standard matrix equations to obtain closed form solutions. A comprehensive 9-DOF tractor semi-trailer model is used

A Survey of Floor Vibration Noise at All Sectors in the APS Experiment Hall

Energy Technology Data Exchange (ETDEWEB)

Kearney, Steven [Argonne National Lab. (ANL), Argonne, IL (United States); Shu, Deming [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-01-01

A vibration survey of the APS experiment hall floor was conducted. It was found that beamlines 10-20 have particularly low levels of vibration when compared to the rest of the facility. The vibration spectrum for each beamline floor can be found in the appendix. Throughout the majority of the 5-100 Hz vibration spectrum beamlines at the APS fall below the most stringent NEST vibration criteria. Lastly, it was concluded that the magnitude of vibrations at a particular beamline is largely dependent upon the magnitude of vibrations present at the nearby mezzanine support column.

Vibration Disturbance Damping System Design to Protect Payload of the Rocket

Directory of Open Access Journals (Sweden)

Sutisno Sutisno

2012-12-01

Full Text Available Rocket motor generates vibrations acting on whole rocket body including its contents. Part of the body which is sensitive to disturbance is the rocket payload. The payload consists of various electronic instruments including: transmitter, various sensors, accelerometer, gyro, the embedded controller system, and others. This paper presents research on rocket vibration influence to the payload and the method to avoid disturbance. Avoiding influence of vibration disturbance can be done using silicone gel material whose typical damping factors are relatively high. The rocket vibration was simulated using electromagnetic motor, and the vibrations were measured using an accelerometer sensor. The measurement results were displayed in the form of curve, indicating the vibration level on some parts of the tested material. Some measurement results can be applied to determine the good material to attenuate vibration disturbance on the instruments of the payload.

Whole-Body Vibration in Farming: Background Document for Creating a Simplified Procedure to Determine Agricultural Tractor Vibration Comfort

Directory of Open Access Journals (Sweden)

Maurizio Cutini

2017-09-01

Full Text Available Operator exposure to high levels of whole-body vibration (WBV presents risks to health and safety and it is reported to worsen or even cause back injuries. Work activities resulting in operator exposure to whole-body vibration have a common onset in off-road work such as farming. Despite the wide variability of agricultural surface profiles, studies have shown that with changing soil profile and tractor speed, the accelerations resulting from ground input present similar spectral trends. While on the one hand such studies confirmed that tractor WBV emission levels are very dependent upon the nature of the operation performed, on the other, irrespective of the wide range of conditions characterizing agricultural operations, they led researchers to set up a possible and realistic simplification and standardization of tractor driver comfort testing activities. The studies presented herewith indicate the usefulness, and the possibility, of developing simplified procedures to determine agricultural tractor vibration comfort. The results obtained could be used effectively to compare tractors of the same category or a given tractor when equipped with different seats, suspension, tyres, etc.

Vibration reduction at the engine-pumps assembly of the main moderator system

International Nuclear Information System (INIS)

Holostencu, Adriana; Dinu, Marius

2005-01-01

Problem of decreasing vibrations in the main moderator motor at Cernavoda NPP - Unit 1 is presented. The moderator pumps are of centrifugal, vertical, single stage and double suction type. Each pump is provided with a main motor (690 Kw, 50 Hz, 6 KV) capable of full rotative speed and a secondary motor, also known as 'pony motor' (15 Kw, 50 Hz, 380 V) capable of a quarter of the full speed. At starting-commissioning stage of Cernavoda NPP, the vibration level in the moderator pump - motor assembly had an average value of 6 mm/s with spurious peaks up to 8 mm/s. It has to be mentioned that operation with a high vibration level may lead to: - a premature wear of the motor bearings; - extra stresses and fatigue in the material of pump and associated pipes. In order to maintain vibration speed to the design limit, the NPP personnel have started investigations since 1997. The main activities were: - verification of the vibration measuring loops; - checking the torque of the bolts that hold the motor's case; - measuring the start-up and nominal currents of the motors in order to determine any phase unbalance; - adjusting the spring hangers from the pumps discharge with simultaneous monitoring of the motor vibration level; - installation of rubber pads in the gap between the motor lugs and the existing seismic supports. None of these actions revealed deviations from the installation requirements or operating parameters. In 1999, a contract with EUROTEST S. A and Stevenson was signed, in order to find a solution to reduce the vibration level. The EUROTEST/ Stevenson action plan contains de following main activities: 1. Creating a calculus model of the moderator system, based on the design drawings provided by Cernavoda NPP; 2. Preparing and performing the vibration measurements in various points of the system; 3. Analyzing the measurements results; 4. Calibrating the calculus model created in step 1, according with the field measurements; 5. Propose a solution to reduce

Sound and vibration sensitivity of VIIIth nerve fibers in the grassfrog, Rana temporaria

DEFF Research Database (Denmark)

Christensen-Dalsgaard, J; Jørgensen, M B

1996-01-01

thresholds from 0.02 cm/s2. The sound and vibration sensitivity was compared for each fiber using the offset between the rate-level curves for sound and vibration stimulation as a measure of relative vibration sensitivity. When measured in this way relative vibration sensitivity decreases with frequency from......We have studied the sound and vibration sensitivity of 164 amphibian papilla fibers in the VIIIth nerve of the grassfrog, Rana temporaria. The VIIIth nerve was exposed using a dorsal approach. The frogs were placed in a natural sitting posture and stimulated by free-field sound. Furthermore......, the animals were stimulated with dorso-ventral vibrations, and the sound-induced vertical vibrations in the setup could be canceled by emitting vibrations in antiphase from the vibration exciter. All low-frequency fibers responded to both sound and vibration with sound thresholds from 23 dB SPL and vibration...

Role of upper-level wind shear on the structure and maintenance of derecho-producing convective systems

Science.gov (United States)

Coniglio, Michael Charles

Common large-scale environments associated with the development of derecho-producing convective systems from a large number of events are identified using statistical clustering of the 500-mb geopotential heights as guidance. The majority of the events (72%) fall into three main patterns that include a well-defined upstream trough (40%), a ridge (20%), and a zonal, low-amplitude flow (12%), which is defined as an additional warm-season pattern that is not identified in past studies of derecho environments. Through an analysis of proximity soundings, discrepancies are found in both low-level and deep-tropospheric shear parameters between observations and the shear profiles considered favorable for strong, long-lived convective systems in idealized simulations. To explore the role of upper-level shear in derecho environments, a set of two-dimensional simulations of density currents within a dry, neutrally stable environment are used to examine the ability of a cold pool to lift environmental air within a vertically sheared flow. The results confirm that the addition of upper-level shear to a wind profile with weak to moderate low-level shear increases the vertical displacement of low-level parcels despite a decrease in the vertical velocity along the cold pool interface, as suggested by previous studies. Parcels that are elevated above the surface (1-2 km) overturn and are responsible for the deep lifting in the deep-shear environments. This deep overturning caused by the upper-level shear helps to maintain the tilt of the convective systems in more complex two-dimensional and three dimensional simulations. The overturning also is shown to greatly increase the size of the convective systems in the three-dimensional simulations by facilitating the initiation and maintenance of convective cells along the cold pool. When combined with estimates of the cold pool motion and the storm-relative hodograph, these results may best be used for the prediction of the demise of

Deviations from the Boltzmann distribution in vibrationally excited gas flows

International Nuclear Information System (INIS)

Offenhaeuser, F.; Frohn, A.

1986-01-01

A new model for the exchange of vibrational energy in one-dimensional flows of CO 2 -H 2 O-N 2 -O 2 -He gas mixtures is presented. In contrast to previous models, the assumption of local Boltzmann distributions for the vibrational degrees of freedom is not required. This generalization was achieved by the assumption that the molecules are harmonic oscillators with one or more degrees of freedom represented by finite numbers of energy levels. The population densities of these energy levels are coupled by a set of rate equations. It is shown that in some cases of molecular gas flow the Boltzmann distribution for the vibrational degrees of freedom may be disturbed. 12 references

Personality Type and Student Performance in Upper-Level Economics Courses: The Importance of Race and Gender.

Science.gov (United States)

Borg, Mary O.; Stranahan, Harriet A.

2002-01-01

Demonstrates that personality type is an important explanatory variable in student performance in upper level economics courses. Finds that certain personality types, combined with race and gender effects, produce students who outperform other students. Introverts and those with the Keirsey-Bates temperament combination of sensing/judging…

Vibration behavior of the artificial barrier system

Energy Technology Data Exchange (ETDEWEB)

Mikoshiba, Tadashi; Ogawa, Nobuyuki; Nakamura, Izuru [National Research Inst. for Earth sceince and Disaster Prevention (Japan)

2000-02-01

This study aims at production of a mimic specimen of artificial barrier, experimental elucidation of influence of seismic motion due to a vibration experiment on the artificial barrier system, and establishment of an evaluating method on its long-term behavior. The study has been carried out under a cooperative study of the National Research Institute for Earth Science and Disaster Prevention and the Japan Nuclear Cycle Development Institute. In 1998 fiscal year, an artificial barrier specimen initiated by crosscut road was produced, and their random wave and actual seismic wave vibrations were carried out to acquire their fundamental data. As a result of the both vibrations, it was found that in a Case 2 specimen of which buffer material was swelled by poured water, the material was integrated with a mimic over-pack to vibrate under judgement of eigen-frequency, maximum acceleration ratio, and so forth on the test results. And, in a Case 1 specimen, it was thought that the mimic over-pack showed an extreme non-linear performance (soft spring) because of reducing eigen-frequency with increase of its vibration level. (G.K.)

Vibration behavior of the artificial barrier system

International Nuclear Information System (INIS)

Mikoshiba, Tadashi; Ogawa, Nobuyuki; Nakamura, Izuru

2000-01-01

This study aims at production of a mimic specimen of artificial barrier, experimental elucidation of influence of seismic motion due to a vibration experiment on the artificial barrier system, and establishment of an evaluating method on its long-term behavior. The study has been carried out under a cooperative study of the National Research Institute for Earth Science and Disaster Prevention and the Japan Nuclear Cycle Development Institute. In 1998 fiscal year, an artificial barrier specimen initiated by crosscut road was produced, and their random wave and actual seismic wave vibrations were carried out to acquire their fundamental data. As a result of the both vibrations, it was found that in a Case 2 specimen of which buffer material was swelled by poured water, the material was integrated with a mimic over-pack to vibrate under judgement of eigen-frequency, maximum acceleration ratio, and so forth on the test results. And, in a Case 1 specimen, it was thought that the mimic over-pack showed an extreme non-linear performance (soft spring) because of reducing eigen-frequency with increase of its vibration level. (G.K.)

Dehydroepiandrosterone Supplementation Combined with Whole-Body Vibration Training Affects Testosterone Level and Body Composition in Mice.

Science.gov (United States)

Chen, Wen-Chyuan; Chen, Yi-Ming; Huang, Chi-Chang; Tzeng, Yen-Dun

2016-01-01

Dehydroepiandrosterone (DHEA), the most abundant sex steroid, is primarily secreted by the adrenal gland and a precursor hormone used by athletes for performance enhancement. Whole-body vibration (WBV) is a well-known light-resistance exercise by automatic adaptations to rapid and repeated oscillations from a vibrating platform, which is also a simple and convenient exercise for older adults. However, the potential effects of DHEA supplementation combined with WBV training on to body composition, exercise performance, and hormone regulation are currently unclear. The objective of the study is to investigate the effects of DHEA supplementation combined with WBV training on body composition, exercise performance, and physical fatigue-related biochemical responses and testosterone content in young-adult C57BL/6 mice. In this study, male C57BL/6 mice were divided into four groups (n = 8 per group) for 6-weeks treatment: sedentary controls with vehicle (SC), DHEA supplementation (DHEA, 10.2 mg/kg), WBV training (WBV; 5.6 Hz, 2 mm, 0.13 g), and WBV training with DHEA supplementation (WBV+DHEA; WBV: 5.6 Hz, 2 mm, 0.13 g and DHEA: 10.2 mg/kg). Exercise performance was evaluated by forelimb grip strength and exhaustive swimming time, as well as changes in body composition and anti-fatigue levels of serum lactate, ammonia, glucose, creatine kinase (CK), and blood urea nitrogen (BUN) after a 15-min swimming exercise. In addition, the biochemical parameters and the testosterone content were measured at the end of the experiment. Six-week DHEA supplementation alone significantly increased mice body weight (BW), muscle weight, testosterone level, and glycogen contents (liver and muscle) when compared with SC group. DHEA supplementation alone had no negative impact on all tissue and biochemical profiles, but could not improve exercise performance. However, WBV+DHEA supplementation also significantly decreased BW, testosterone level and glycogen content of liver, as well as serum

Fingers' vibration transmission and grip strength preservation performance of vibration reducing gloves.

Science.gov (United States)

Hamouda, K; Rakheja, S; Dewangan, K N; Marcotte, P

2018-01-01

The vibration isolation performances of vibration reducing (VR) gloves are invariably assessed in terms of power tools' handle vibration transmission to the palm of the hand using the method described in ISO 10819 (2013), while the nature of vibration transmitted to the fingers is ignored. Moreover, the VR gloves with relatively low stiffness viscoelastic materials affect the grip strength in an adverse manner. This study is aimed at performance assessments of 12 different VR gloves on the basis of handle vibration transmission to the palm and the fingers of the gloved hand, together with reduction in the grip strength. The gloves included 3 different air bladder, 3 gel, 3 hybrid, and 2 gel-foam gloves in addition to a leather glove. Two Velcro finger adapters, each instrumented with a three-axis accelerometer, were used to measure vibration responses of the index and middle fingers near the mid-phalanges. Vibration transmitted to the palm was measured using the standardized palm adapter. The vibration transmissibility responses of the VR gloves were measured in the laboratory using the instrumented cylindrical handle, also described in the standard, mounted on a vibration exciter. A total of 12 healthy male subjects participated in the study. The instrumented handle was also used to measure grip strength of the subjects with and without the VR gloves. The results of the study showed that the VR gloves, with only a few exceptions, attenuate handle vibration transmitted to the fingers only in the 10-200 Hz and amplify middle finger vibration at frequencies exceeding 200 Hz. Many of the gloves, however, provided considerable reduction in vibration transmitted to the palm, especially at higher frequencies. These suggest that the characteristics of vibration transmitted to fingers differ considerably from those at the palm. Four of the test gloves satisfied the screening criteria of the ISO 10819 (2013) based on the palm vibration alone, even though these caused

Whole-body vibration exercise in postmenopausal osteoporosis

Directory of Open Access Journals (Sweden)

Magdalena Weber-Rajek

2015-01-01

Full Text Available The report of the World Health Organization (WHO of 2008 defines osteoporosis as a disease characterized by low bone mass and an increased risk of fracture. Postmenopausal osteoporosis is connected to the decrease in estrogens concentration as a result of malfunction of endocrine ovarian function. Low estrogens concentration causes increase in bone demineralization and results in osteoporosis. Physical activity, as a component of therapy of patients with osteoporosis, has been used for a long time now. One of the forms of safe physical activity is the vibration training. Training is to maintain a static position or execution of specific exercises involving the appropriate muscles on a vibrating platform, the mechanical vibrations are transmitted to the body of the patient. According to the piezoelectric theory, pressure induces bone formation in the electrical potential difference, which acts as a stimulant of the process of bone formation. Whole body vibration increases the level of growth hormone and testosterone in serum, preventing sarcopenia and osteoporosis. The aim of this study was to review the literature on vibration exercise in patients with postmenopausal osteoporosis based on the PubMed and Medline database. While searching the database, the following key words were used ‘postmenopausal osteoporosis’ and ‘whole-body vibration exercise’.

PREFACE: Vibrations at surfaces Vibrations at surfaces

Science.gov (United States)

Rahman, Talat S.

2011-12-01

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

Vibrational spectroscopy in the electron microscope.

Science.gov (United States)

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

2014-10-09

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

Frequency identification of vibration signals using video camera image data.

Science.gov (United States)

Jeng, Yih-Nen; Wu, Chia-Hung

2012-10-16

This study showed that an image data acquisition system connecting a high-speed camera or webcam to a notebook or personal computer (PC) can precisely capture most dominant modes of vibration signal, but may involve the non-physical modes induced by the insufficient frame rates. Using a simple model, frequencies of these modes are properly predicted and excluded. Two experimental designs, which involve using an LED light source and a vibration exciter, are proposed to demonstrate the performance. First, the original gray-level resolution of a video camera from, for instance, 0 to 256 levels, was enhanced by summing gray-level data of all pixels in a small region around the point of interest. The image signal was further enhanced by attaching a white paper sheet marked with a black line on the surface of the vibration system in operation to increase the gray-level resolution. Experimental results showed that the Prosilica CV640C CMOS high-speed camera has the critical frequency of inducing the false mode at 60 Hz, whereas that of the webcam is 7.8 Hz. Several factors were proven to have the effect of partially suppressing the non-physical modes, but they cannot eliminate them completely. Two examples, the prominent vibration modes of which are less than the associated critical frequencies, are examined to demonstrate the performances of the proposed systems. In general, the experimental data show that the non-contact type image data acquisition systems are potential tools for collecting the low-frequency vibration signal of a system.

Frequency Identification of Vibration Signals Using Video Camera Image Data

Directory of Open Access Journals (Sweden)

Chia-Hung Wu

2012-10-01

Full Text Available This study showed that an image data acquisition system connecting a high-speed camera or webcam to a notebook or personal computer (PC can precisely capture most dominant modes of vibration signal, but may involve the non-physical modes induced by the insufficient frame rates. Using a simple model, frequencies of these modes are properly predicted and excluded. Two experimental designs, which involve using an LED light source and a vibration exciter, are proposed to demonstrate the performance. First, the original gray-level resolution of a video camera from, for instance, 0 to 256 levels, was enhanced by summing gray-level data of all pixels in a small region around the point of interest. The image signal was further enhanced by attaching a white paper sheet marked with a black line on the surface of the vibration system in operation to increase the gray-level resolution. Experimental results showed that the Prosilica CV640C CMOS high-speed camera has the critical frequency of inducing the false mode at 60 Hz, whereas that of the webcam is 7.8 Hz. Several factors were proven to have the effect of partially suppressing the non-physical modes, but they cannot eliminate them completely. Two examples, the prominent vibration modes of which are less than the associated critical frequencies, are examined to demonstrate the performances of the proposed systems. In general, the experimental data show that the non-contact type image data acquisition systems are potential tools for collecting the low-frequency vibration signal of a system.

Study on vibration behaviors of engineered barrier system

Energy Technology Data Exchange (ETDEWEB)

Mikoshiba, Tadashi; Ogawa, Nobuyuki; Minowa, Chikahiro [National Research Inst. for Earth Science and Disaster Prevention, Tsukuba, Ibaraki (Japan)

1999-02-01

Small engineered barrier model was mode and tested by vibrating with the random wave and the real earthquake wave. The wave observed at Kamaishi (N-S, N-W), Iwate Prefecture, in September 6, 1993, and Kobe (N-S) etc. were used as the real earthquake waves. The trial overpack showed non-linear characteristics (soft spring) by vibrating with the random wave. The pressure and acceleration of trial overpack and constraint container increased with increasing the vibration level of the real earthquake wave. The trial overpack moved the maximum 1.7 mm of displacement and 16 mm subsidence. The results showed both waves rocked the trialpack. (S.Y.)

Teaching Introductory Upper-Level Religion and Theology Classes

Science.gov (United States)

Clingerman, Forrest; O'Brien, Kevin J.

2015-01-01

The undergraduate study of religion is predominantly undertaken by non-majors who are meeting a general education requirement. This means that, while curricular discussions make important distinctions between the work of lower- and upper-division courses, many religion and theology faculty are teaching hybrid courses that we call…

Implausibility of the vibrational theory of olfaction.

Science.gov (United States)

Block, Eric; Jang, Seogjoo; Matsunami, Hiroaki; Sekharan, Sivakumar; Dethier, Bérénice; Ertem, Mehmed Z; Gundala, Sivaji; Pan, Yi; Li, Shengju; Li, Zhen; Lodge, Stephene N; Ozbil, Mehmet; Jiang, Huihong; Penalba, Sonia F; Batista, Victor S; Zhuang, Hanyi

2015-05-26

The vibrational theory of olfaction assumes that electron transfer occurs across odorants at the active sites of odorant receptors (ORs), serving as a sensitive measure of odorant vibrational frequencies, ultimately leading to olfactory perception. A previous study reported that human subjects differentiated hydrogen/deuterium isotopomers (isomers with isotopic atoms) of the musk compound cyclopentadecanone as evidence supporting the theory. Here, we find no evidence for such differentiation at the molecular level. In fact, we find that the human musk-recognizing receptor, OR5AN1, identified using a heterologous OR expression system and robustly responding to cyclopentadecanone and muscone, fails to distinguish isotopomers of these compounds in vitro. Furthermore, the mouse (methylthio)methanethiol-recognizing receptor, MOR244-3, as well as other selected human and mouse ORs, responded similarly to normal, deuterated, and (13)C isotopomers of their respective ligands, paralleling our results with the musk receptor OR5AN1. These findings suggest that the proposed vibration theory does not apply to the human musk receptor OR5AN1, mouse thiol receptor MOR244-3, or other ORs examined. Also, contrary to the vibration theory predictions, muscone-d30 lacks the 1,380- to 1,550-cm(-1) IR bands claimed to be essential for musk odor. Furthermore, our theoretical analysis shows that the proposed electron transfer mechanism of the vibrational frequencies of odorants could be easily suppressed by quantum effects of nonodorant molecular vibrational modes. These and other concerns about electron transfer at ORs, together with our extensive experimental data, argue against the plausibility of the vibration theory.

A novel triple-actuating mechanism of an active air mount for vibration control of precision manufacturing machines: experimental work

International Nuclear Information System (INIS)

Kim, Hyung-Tae; Kim, Cheol-Ho; Choi, Seung-Bok; Moon, Seok-Jun; Song, Won-Gil

2014-01-01

With the goal of vibration control and isolation in a clean room, we propose a new type of air mount which consists of pneumatic, electromagnetic (EM), and magnetorheological (MR) actuators. The air mount is installed below a semiconductor manufacturing machine to reduce the adverse effects caused by unwanted vibration. The proposed mechanism integrates the forces in a parallel connection of the three actuators. The MR part is designed to operate in an air spring in which the EM part is installed. The control logic is developed with a classical method and a switching mode to avoid operational mismatch among the forces developed. Based on extended microprocessors, a portable, embedded controller is installed to execute both nonlinear logic and digital communication with the peripherals. The pneumatic forces constantly support the heavy weight of an upper structure and maintain the level of the air mount. The MR damper handles the transient response, while the EM controller reduces the resonance response, which is switched mutually with a threshold. Vibration is detected by laser displacement sensors which have submicron resolution. The impact test results of three tons load weight demonstrate practical feasibility by showing that the proposed triple-actuating mechanism can reduce the transient response as well as the resonance in the air mount, resulting in accurate motion of the semiconductor manufacturing machine. (technical note)

Combined Euler column vibration isolation and energy harvesting

Science.gov (United States)

Davis, R. B.; McDowell, M. D.

2017-05-01

A new device that combines vibration isolation and energy harvesting is modeled, simulated, and tested. The vibration isolating portion of the device uses post-buckled beams as its spring elements. Piezoelectric film is applied to the beams to harvest energy from their dynamic flexure. The entire device operates passively on applied base excitation and requires no external power or control system. The structural system is modeled using the elastica, and the structural response is applied as forcing on the electric circuit equation to predict the output voltage and the corresponding harvested power. The vibration isolation and energy harvesting performance is simulated across a large parameter space and the modeling approach is validated with experimental results. Experimental transmissibilities of 2% and harvested power levels of 0.36 μW are simultaneously demonstrated. Both theoretical and experimental data suggest that there is not necessarily a trade-off between vibration isolation and harvested power. That is, within the practical operational range of the device, improved vibration isolation will be accompanied by an increase in the harvested power as the forcing frequency is increased.

Vibration and recoil control of pneumatic hammers. [by air flow pressure regulation

Science.gov (United States)

Constantinescu, I. N.; Darabont, A. V.

1974-01-01

Vibration sources are described for pneumatic hammers used in the mining industry (pick hammers), in boiler shops (riveting hammers), etc., bringing to light the fact that the principal vibration source is the variation in air pressure inside the cylinder. The present state of the art of vibration control of pneumatic hammers as it is practiced abroad, and the solutions adopted for this purpose, are discussed. A new type of pneumatic hammer with a low noise and vibration level is presented.

Evaluation of dynamic properties of soft ground using an S-wave vibrator and seismic cones. Part 2. Vs change during the vibration; S ha vibrator oyobi seismic cone wo mochiita gen`ichi jiban no doteki bussei hyoka. 2. Kashinchu no Vs no henka

Energy Technology Data Exchange (ETDEWEB)

Inazaki, T [Public Works Research Institute, Tsukuba (Japan)

1997-05-27

With an objective to measure a behavior of the surface ground during a strong earthquake directly on the actual ground and make evaluation thereon, a proposal was made on an original location measuring and analyzing method using an S-wave vibrator and seismic cones. This system consists of an S-wave vibrator and a static cone penetrating machine, and different types of measuring cones. A large number of measuring cones are inserted initially in the object bed of the ground, and variation in the vibration generated by the vibrator is measured. This method can derive decrease in rigidity rate of the actual ground according to dynamic strain levels, or in other words, the dynamic nonlinearity. The strain levels can be controlled with a range from 10 {sup -5} to 10 {sup -3} by varying the distance from the S-wave vibrator. Furthermore, the decrease in the rigidity rate can be derived by measuring variations in the S-wave velocity by using the plank hammering method during the vibration. Field measurement is as easy as it can be completed in about half a day including preparatory works, and the data analysis is also simple. The method is superior in mobility and workability. 9 figs.

Identification and reduction of vibration and noise of a glass tempering system

International Nuclear Information System (INIS)

Ashhab, M S

2015-01-01

The vibration and noise of a glass tempering machine at a factory are studied. Experiments were conducted to identify the sources of vibration and noise. It was found that main sources for vibration and noise are two air barrels, the air pipes from the fans to the glass tempering machine and the fans location. Solutions were suggested to reduce vibration and noise from these three main sources. One of the solutions that were implemented is placing rubber dampers beneath the air barrels and pipes which almost cancelled the horizontal vibrations in the building structure and reduced the vertical vibrations to a low value most likely coming from noise. There are two types of noise, namely, radiation noise from the fans through the fans room walls and transmitted noise through the pipes caused by turbulence. A glass wool noise insulating layer was installed on the wall between the fans room and factory to reduce radiation noise through this wall. Part of the air pipe system in the factory is made of a light material which produced the highest levels of noise above 110 dBA. These air pipes were wrapped by glass wool rolls and the noise level near them was reduced to below 100 dBA which comes from other machine parts. In addition, noise levels were reduced between 2 and 15 dBA at different points in the factory. (paper)

Report on design and technical standard planning of vibration controlling structure on the buildings, in the Tokai Reprocessing Facility, Power Reactor and Nuclear Fuel Development Corporation

International Nuclear Information System (INIS)

Uryu, Mitsuru; Terada, Shuji; Shinohara, Takaharu; Yamazaki, Toshihiko; Nakayama, Kazuhiko; Kondo, Toshinari; Hosoya, Hisashi

1997-10-01

The Tokai reprocessing facility buildings are constituted by a lower foundation, vibration controlling layers, and upper structure. At the vibration controlling layer, a laminated rubber aiming support of the building load and extension of the eigenfrequency and a damper aiming absorption of earthquake energy are provided. Of course, the facility buildings are directly supported at the arenaceous shale (Taga Layer) of the Miocene in the Neogene confirmed to the stablest ground, as well the buildings with high vibration resistant importance in Japan. This report shows that when the vibration controlling structure is adopted for the reprocessing facility buildings where such high vibration resistance is required, reduction of input acceleration for equipments and pipings can be achieved and the earthquake resistant safety can also be maintained with sufficient tolerance and reliability. (G.K.)

Experimental investigation of railway train-induced vibrations of surrounding ground and a nearby multi-story building

Science.gov (United States)

Xia, He; Chen, Jianguo; Wei, Pengbo; Xia, Chaoyi; de Roeck, G.; Degrande, G.

2009-03-01

In this paper, a field experiment was carried out to study train-induced environmental vibrations. During the field experiment, velocity responses were measured at different locations of a six-story masonry structure near the Beijing-Guangzhou Railway and along a small road adjacent to the building. The results show that the velocity response levels of the environmental ground and the building floors increase with train speed, and attenuate with the distance to the railway track. Heavier freight trains induce greater vibrations than lighter passenger trains. In the multi-story building, the lateral velocity levels increase monotonically with floor elevation, while the vertical ones increase with floor elevation in a fluctuating manner. The indoor floor vibrations are much lower than the outdoor ground vibrations. The lateral vibration of the building along the direction of weak structural stiffness is greater than along the direction with stronger stiffness. A larger room produces greater floor vibrations than the staircase at the same elevation, and the vibration at the center of a room is greater than at its corner. The vibrations of the building were compared with the Federal Transportation Railroad Administration (FTA) criteria for acceptable ground-borne vibrations expressed in terms of rms velocity levels in decibels. The results show that the train-induced building vibrations are serious, and some exceed the allowance given in relevant criterion.

Student Perceived and Determined Knowledge of Biology Concepts in an Upper-Level Biology Course

OpenAIRE

Ziegler, Brittany; Montplaisir, Lisa

2014-01-01

Students who lack metacognitive skills can struggle with the learning process. To be effective learners, students should recognize what they know and what they do not know. This study examines the relationship between students’ perception of their knowledge and determined knowledge in an upper-level biology course utilizing a pre/posttest approach. Significant differences in students’ perception of their knowledge and their determined knowledge exist at the beginning (pretest) and end (postte...

Vibrational relaxation induced population inversions in laser pumped polyatomic molecules

International Nuclear Information System (INIS)

Shamah, I.; Flynn, G.; Columbia Univ., New York

1981-01-01

Conditions for population inversion in laser pumped polyatomic molecules are described. For systems which exhibit metastable vibrational population distributions, large, long lived inversions are possible even when the vibrational modes are strongly coupled by rapid collisional vibration-vibration (V-V) energy transfer. Overtone states of a hot mode are found to invert with respect to fundamental levels of a cold mode even at V-V steady state. Inversion persists for a V-T/R relaxation time. A gain of 4 m -1 for the 2ν 3 → ν 2 transition in CH 3 F (lambda approx. 15.9 μ) was found assuming a spontaneous emission lifetime of 10 s for this transition. General equations are derived which can be used to determine the magnitude of population inversion in any laser pumped, vibrationally metastable, polyatomic molecule. A discussion of factors controlling the population maxima of different vibrational states in optically pumped, V-V equilibrated metastable polyatomics is also given. (orig./WL)

Exposure to vibrations in wine growing

Directory of Open Access Journals (Sweden)

Domenico Pessina

2013-09-01

Full Text Available Apart the winter period, the activity in specialized agricultural cultivations (i.e. wine- and fruit-growing is distributed for a long period of the year. Some tasks, such as pesticide distribution, are repeated several times during the growing season. On the other hand, mechanization is one of the pillars on which is based the modern agriculture management. As a consequence, in wine growing the tractor driver has to be considered a worker potentially subjected to high level of vibrations, due to the poor machinery conditions often encountered, and sometimes to the rough soil surface of the vineyard combined with the high travelling speed adopted in carrying out many operations. About vibrations, the Italian Decree 81/08 basically refers to the European Directive 2002/44/CE, that provides some very strict limits of exposure, both for whole body and hand-arm districts. In Oltrepo pavese, a large hilly area located the south part of the Pavia province (Lombardy - Italy wine growing is the main agricultural activity; for this reason, a detailed survey on the vibration levels recorded at the tractor driver’s seat was carried out, in order to ascertain the real risk to which the operators are exposed. The activity in wine growing has been classified into 6 groups of similar tasks, as follows: 1. canopy management: pruning, trimming, binding, stripping, etc.; 2. soil management: harrowing, hoeing, subsoiling etc.; 3. inter-row management: chopping of pruning , pinching, grass mowing, etc.; 4. crop protection: pesticides and fungicides distribution, sulfidation, foliar fertilization, etc.; 5. grape harvesting: manual or mechanical; 6. transport: from the vineyard to the cellar. For each group of tasks, the vibration levels on 3 the traditional axes (x, y and z were recorded, and then an exposure time was calculated for each of them, in order to ascertain the risk level in comparison to what provided by the dedicated standard. Finally, a detailed

Modeling study of vibrational photochemical isotope enrichment. [HBr + Cl/sub 2/; HCl + Br/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Badcock, C.C.; Hwang, W.C.; Kalsch, J.F.

1978-09-29

Chemical kinetic modeling studies of vibrational-photochemical isotope enrichment have been performed on two systems: Model (I), H/sup 79/Br(H/sup 81/Br) + Cl/sub 2/ and, Model (II), H/sup 37/Cl(H/sup 35/Cl) + Br. Pulsed laser excitation was modeled to the first excited vibrational level of H/sup 79/Br in Model I and the first and second excited vibrational levels of both HCl isotopes in Model II. These are prototype systems of exoergic (Model I) and endoergic (Model II) reactions. The effects on enrichment of varying the external parameters (pressure, laser intensity) and the internal parameters (rate constants for V-V exchange and excited-state reactions) were examined. Studies of these prototype systems indicate that a favorable reaction for enrichment, with isotopically-specific excitation and a significantly accelerated vibrationally-excited-state reaction should have the following properties: the reaction from v = 0 should be only moderately exoergic, and the most favorable coreactant should be a polyatomic species, such as alkyl radical. Direct excitation of the reacting vibrational level is at least an order of magnitude more favorable for enrichment than is population by energy transfer. Enrichment of the minor isotope by these processes is more effective than is major isotope enrichment. Within limits, increased laser intensity is beneficial. However, for sequential excitation of a second vibrational level, major isotope enrichment can be diminished by high populations of the first vibrational level.

Education Pays Off! On Transition to Work for 25 Year Olds in Norway with Upper Secondary Education or Lower as Their Highest Educational Level

Science.gov (United States)

Markussen, Eifred

2017-01-01

In this article we examine the relationship between educational level and position in the labour market at age 25 for those who have completed upper secondary education or lower as their highest educational level. Whilst completion of upper secondary education is widely regarded as being important, we find that early and lasting work experience…

Effect of nonlinearity of connecting dampers on vibration control of connected building structures

Directory of Open Access Journals (Sweden)

Masatoshi eKasagi

2016-01-01

Full Text Available The connection of two building structures with dampers is one of effective vibration control systems. In this vibration control system, both buildings have to possess different vibration properties in order to provide a higher vibration reduction performance. In addition to such condition of different vibration properties of both buildings, the connecting dampers also play an important role in the vibration control mechanism. In this paper, the effect of nonlinearity of connecting dampers on the vibration control of connected building structures is investigated in detail. A high-damping rubber damper and an oil damper with and without relief mechanism are treated. It is shown that, while the high-damping rubber damper is effective in a rather small deformation level, the linear oil damper is effective in a relatively large deformation level. It is further shown that, while the oil dampers reduce the response in the same phase as the case without dampers, the high-damping rubber dampers change the phase. The merit is that the high-damping rubber can reduce the damper deformation and keep the sufficient space between both buildings. This can mitigate the risk of building pounding.

Piping vibrations measured during FFTF startup

International Nuclear Information System (INIS)

Anderson, M.J.

1981-03-01

An extensive vibration survey was conducted on the Fast Flux Test Facility piping during the plant acceptance test program. The purpose was to verify that both mechanical and flow induced vibration amplitudes were of sufficiently low level so that pipe and pipe support integrity would not be compromised over the plant design lifetime. Excitation sources included main heat transport sodium pumps, reciprocating auxiliary system pumps, EM pumps, and flow oscillations. Pipe sizes varied from one-inch to twenty-eight-inches in diameter. This paper describes the test plan; the instrumentation and procedures utilized; and the test results

Nuclear resonance vibrational spectroscopic studies of iron-containing biomolecules

International Nuclear Information System (INIS)

Ohta, Takehiro; Seto, Makoto

2014-01-01

In this review, we report recent nuclear resonance vibrational spectroscopic (NRVS) studies of iron-containing biomolecules and their model complexes. The NRVS is synchrotron-based element-specific vibrational spectroscopic methods. Unlike Raman and infrared spectroscopy, the NRVS can investigate all iron motions without selection rules, which provide atomic level insights into the structure/reactivity correlation of biologically relevant iron complexes. (author)

Isolation of I and C cabinets against shocks, vibrations and seismic movements

International Nuclear Information System (INIS)

Ciocan, George; Zamfir, Madalina; Florea, Ioana; Androne, Marian; Serban, Viorel; Prisecaru, Ilie

2007-01-01

This paper presents SERB-CITON solution to isolate the I and C cabinets against shocks, vibrations and seismic movements. The seismic qualification is required because the I and C components installed inside the cabinets are generally sensitive to shocks, vibrations and seismic movements and many times, the manufacturer does not guarantee them for a level of shocks, vibrations and seismic movements higher and equal to the level corresponding to the location where they are installed. The document also presents the solution to isolate such I and C cabinets associated to the hydrogen sulfide compressors located in ROMAG-PROD Drobeta Turnu-Severin. (authors)

Analysis of vibration characteristics of a prestressed concrete cable-stayed bridge using strong motion observation data. Jishin kansoku ni motozuku PC shachokyo no shindo tokusei no kaiseki

Energy Technology Data Exchange (ETDEWEB)

Inatomi, T. (Port and Harbour Research Institute, Kanagawa (Japan)); Takeda, T.; Obi, N.; Yamanobe, S. (Kajima Corp., Tokyo (Japan))

1994-05-31

Records of seismic observation were analyzed for the purpose of proving the validity of antiseismic design for a prestressed concrete (PC) cable-stayed bridge. This bridge is a three span continuous PC cable-stayed bridge of 498 m in bridge length, and is constructed on alluvial soft ground. The seismometer used is a servo type accelerometer. The observed frequency and mode of seismic vibration are in good agreement with those in the analysis and hence the validity of modelling of the structure in designing was confirmed. It was also confirmed that the bending vibration and torsional vibration of the main girder are separated as designed. However, some points such as a large difference in the observed vibration and analysed vibration in the mode accompanying rotation of the base are listed as problems to be solved in antiseismic design. In order to investigate the attenuation constant of the upper structure, a seismic wave response analysis was performed and its results were compared with observed ones. When the attenuation constant is assumed to be 2%, agreement of data between analysis and observation is good, and it is considered that the attenuation constant of the upper structure only without the effects of attenuation of energy escape from the base and crack generation in concrete was about 2% in the observed earthquake (maximum acceleration on the ground: 51 Gal). 8 refs., 9 figs., 2 tabs.

Nuclear and Particle Physics Simulations: The Consortium of Upper-Level Physics Software

Science.gov (United States)

Bigelow, Roberta; Moloney, Michael J.; Philpott, John; Rothberg, Joseph

1995-06-01

The Consortium for Upper Level Physics Software (CUPS) has developed a comprehensive series of Nine Book/Software packages that Wiley will publish in FY `95 and `96. CUPS is an international group of 27 physicists, all with extensive backgrounds in the research, teaching, and development of instructional software. The project is being supported by the National Science Foundation (PHY-9014548), and it has received other support from the IBM Corp., Apple Computer Corp., and George Mason University. The Simulations being developed are: Astrophysics, Classical Mechanics, Electricity & Magnetism, Modern Physics, Nuclear and Particle Physics, Quantum Mechanics, Solid State, Thermal and Statistical, and Wave and Optics.

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

Mid Holocene lake level and shoreline behavior during the Nipissing phase of the upper Great Lakes at Alpena, Michigan, USA

Science.gov (United States)

Thompson, T.A.; Lepper, K.; Endres, A.L.; Johnston, J.W.; Baedke, S.J.; Argyilan, E.P.; Booth, R.K.; Wilcox, D.A.

2011-01-01

The Nipissing phase was the last pre-modern high-water stage of the upper Great Lakes. Represented as either a one- or two-peak highstand, the Nipissing occurred following a long-term lake-level rise. This transgression was primarily an erosional event with only the final stage of the transgression preserved as barriers, spits, and strandplains of beach ridges. South of Alpena, Michigan, mid to late Holocene coastal deposits occur as a strandplain between Devils Lake and Lake Huron. The landward part of this strandplain is a higher elevation platform that formed during the final stage of lake-level rise to the Nipissing peak. The pre-Nipissing shoreline transgressed over Devils Lake lagoonal deposits from 6.4 to 6.1. ka. The first beach ridge formed ~ 6. ka, and then the shoreline advanced toward Lake Huron, producing beach ridges about every 70. years. This depositional regression produced a slightly thickening wedge of sediment during a lake-level rise that formed 20 beach ridges. The rise ended at 4.5. ka at the Nipissing peak. This peak was short-lived, as lake level fell > 4. m during the following 500. years. During this lake-level rise and subsequent fall, the shoreline underwent several forms of shoreline behavior, including erosional transgression, aggradation, depositional transgression, depositional regression, and forced regression. Other upper Great Lakes Nipissing platforms indicate that the lake-level change observed at Alpena of a rapid pre-Nipissing lake-level rise followed by a slower rise to the Nipissing peak, and a post-Nipissing rapid lake-level fall is representative of mid Holocene lake level in the upper Great Lakes. ?? 2011 Elsevier B.V.

Vibration analysis and vibration damage assessment in nuclear and process equipment

International Nuclear Information System (INIS)

Pettigrew, M.J.; Taylor, C.E.; Fisher, N.J.; Yetisir, M.; Smith, B.A.W.

1997-01-01

Component failures due to excessive flow-induced vibration are still affecting the performance and reliability of process and nuclear components. The purpose of this paper is to discuss flow-induced vibration analysis and vibration damage prediction. Vibration excitation mechanisms are described with particular emphasis on fluid elastic instability. The dynamic characteristics of process and power equipment are explained. The statistical nature of some parameters, in particular support conditions, is discussed. The prediction of fretting-wear damage is approached from several points-of-view. An energy approach to formulate fretting-wear damage is proposed. (author)

Vibration of hydraulic machinery

CERN Document Server

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

2013-01-01

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

Hand-arm vibration in orthopaedic surgery: a neglected risk.

Science.gov (United States)

Mahmood, F; Ferguson, K B; Clarke, J; Hill, K; Macdonald, E B; Macdonald, D J M

2017-12-30

Hand-arm vibration syndrome is an occupational disease caused by exposure to hand-arm transmitted vibration. The Health and Safety Executive has set limits for vibration exposure, including an exposure action value (EAV), where steps should be taken to reduce exposure, and an exposure limit value (ELV), beyond which vibrating equipment must not be used for the rest of the working day. To measure hand-arm transmitted vibration among orthopaedic surgeons, who routinely use hand-operated saws. We undertook a cadaveric study measuring vibration associated with a tibial cut using battery-operated saws. Three surgeons undertook three tibial cuts each on cadaveric tibiae. Measurements were taken using a frequency-weighted root mean square acceleration, with the vibration total value calculated as the root of the sums squared in each of the three axes. A mean (SD) vibration magnitude of 1 (0.2) m/s2 in the X-axis, 10.3 (1.9) m/s2 in the Y-axis and 4.2 (1.3) m/s2 in the Z-axis was observed. The weighted root mean squared magnitude of vibration was 11.3 (1.7) m/s2. These results suggest an EAV of 23 min and ELV of 1 h 33 min using this equipment. Our results demonstrate that use of a battery-operated sagittal saw can transmit levels of hand-arm vibration approaching the EAV or ELV through prolonged use. Further study is necessary to quantify this risk and establish whether surveillance is necessary for orthopaedic surgeons. © The Author 2017. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Vibrations and Eigenvalues

Indian Academy of Sciences (India)

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

Hearing with an atympanic ear: good vibration and poor sound-pressure detection in the royal python, Python regius

DEFF Research Database (Denmark)

Christensen, Christian Bech; Christensen-Dalsgaard, Jakob; Brandt, Christian

2012-01-01

are sensitive to sound pressure and (2) snakes are sensitive to vibrations, but cannot hear the sound pressure per se. Vibration and sound-pressure sensitivities were quantified by measuring brainstem evoked potentials in 11 royal pythons, Python regius. Vibrograms and audiograms showed greatest sensitivity...... at low frequencies of 80-160 Hz, with sensitivities of -54 dB re. 1 m s(-2) and 78 dB re. 20 μPa, respectively. To investigate whether pythons detect sound pressure or sound-induced head vibrations, we measured the sound-induced head vibrations in three dimensions when snakes were exposed to sound...... pressure at threshold levels. In general, head vibrations induced by threshold-level sound pressure were equal to or greater than those induced by threshold-level vibrations, and therefore sound-pressure sensitivity can be explained by sound-induced head vibration. From this we conclude that pythons...

Vibrationally Excited Carbon Monoxide Produced via a Chemical Reaction Between Carbon Vapor and Oxygen

Science.gov (United States)

Jans, Elijah R.; Eckert, Zakari; Frederickson, Kraig; Rich, Bill; Adamovich, Igor V.

2017-06-01

Measurements of the vibrational distribution function of carbon monoxide produced via a reaction between carbon vapor and molecular oxygen has shown a total population inversion on vibrational levels 4-7. Carbon vapor, produced using an arc discharge to sublimate graphite, is mixed with an argon oxygen flow. The excited carbon monoxide is vibrationally populated up to level v=14, at low temperatures, T=400-450 K, in a collision-dominated environment, 15-20 Torr, with total population inversions between v=4-7. The average vibrational energy per CO molecule formed by the reaction is 0.6-1.2 eV/molecule, which corresponds to 10-20% of the reaction enthalpy. Kinetic modeling of the flow reactor, including state specific vibrational processes, was performed to infer the vibrational distribution of the products of the reaction. The results show viability of developing of a new chemical CO laser from the reaction of carbon vapor and oxygen.

Numerical study on flow induced vibration characteristics of heat transfer tube

International Nuclear Information System (INIS)

Feng Zhipeng; Zang Fenggang; Zhang Yixiong

2014-01-01

The model presents a fully coupled approach with solving the fluid flow and the structure vibration simultaneously. The three-dimensional unsteady, viscous, incompressible Navier-Stokes equation and LES turbulence model were solved by the finite volume approach and the heat transfer structure was solved by finite element method combined with moving mesh control technique. The dynamic equilibrium equation was discretized according to the finite element theory and the mesh update was achieved by the dynamic mesh technology. Based on this model, flow induced vibration responses of the tube were thus investigated using response branch, phase angle, Lissajou diagram, trajectory, phase portrait and Poincare section mapping. Meanwhile, the limit cycle and bifurcation of lift coefficient and lateral displacement were analyzed. The results reveal that a quasi-upper branch is found in the fluid-structure interaction system, and there is no bifurcation of lift coefficient and lateral displacement occurred in three-dimensional flexible tube submitted to uniform turbulent flow. (authors)

Handbook Of Noise And Vibration

International Nuclear Information System (INIS)

1995-12-01

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

Structural impact response for assessing railway vibration induced on buildings

Science.gov (United States)

Kouroussis, Georges; Mouzakis, Harris P.; Vogiatzis, Konstantinos E.

2018-03-01

Over the syears, the rapid growth in railway infrastructure has led to numerous environmental challenges. One such significant issue, particularly in urban areas, is ground-borne vibration. A common source of ground-borne vibration is caused by local defects (e.g. rail joints, switches, turnouts, etc.) that generate large amplitude excitations at isolated locations. Modelling these excitation sources is particularly challenging and requires the use of complex and extensive computational efforts. For some situations, the use of experiments and measured data offers a rapid way to estimate the effect of such defects and to evaluate the railway vibration levels using a scoping approach. In this paper, the problem of railway-induced ground vibrations is presented along with experimental studies to assess the ground vibration and ground borne noise levels, with a particular focus on the structural response of sensitive buildings. The behaviour of particular building foundations is evaluated through experimental data collected in Brussels Region, by presenting the expected frequency responses for various types of buildings, taking into account both the soil-structure interaction and the tramway track response. A second study is dedicated to the Athens metro, where transmissibility functions are used to analyse the effect of various Athenian building face to metro network trough comprehensive measurement campaigns. This allows the verification of appropriate vibration mitigation measures. These benchmark applications based on experimental results have been proved to be efficient to treat a complex problem encountered in practice in urban areas, where the urban rail network interacts with important local defects and where the rise of railway ground vibration problems has clearly been identified.

Vibration mode and vibration shape under excitation of a three phase model transformer core

Science.gov (United States)

Okabe, Seiji; Ishigaki, Yusuke; Omura, Takeshi

2018-04-01

Structural vibration characteristics and vibration shapes under three-phase excitation of a archetype transformer core were investigated to consider their influences on transformer noise. Acoustic noise and vibration behavior were measured in a three-limb model transformer core. Experimental modal analysis by impact test was performed. The vibration shapes were measured by a laser scanning vibrometer at different exciting frequencies. Vibration amplitude of the core in out-of-plane direction were relatively larger than those in other two in-plane directions. It was consistent with the result that the frequency response function of the core in out-of-plane direction was larger by about 20 dB or more than those in in-plane directions. There were many vibration modes having bending deformation of limbs in out-of-plane direction. The vibration shapes of the core when excited at 50 Hz and 60 Hz were almost the same because the fundamental frequencies of the vibration were not close to the resonance frequencies. When excitation frequency was 69 Hz which was half of one of the resonance frequencies, the vibration shape changed to the one similar to the resonance vibration mode. Existence of many vibration modes in out-of-plane direction of the core was presumed to be a reason why frequency characteristics of magnetostriction and transformer noise do not coincide.

Vibrational energy transfer in selectively excited diatomic molecules

International Nuclear Information System (INIS)

Dasch, C.J.

1978-09-01

Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295 0 K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295 0 K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ΔJ transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references

Amplitude control of the track-induced self-excited vibration for a maglev system.

Science.gov (United States)

Zhou, Danfeng; Li, Jie; Zhang, Kun

2014-09-01

The Electromagnet Suspension (EMS) maglev train uses controlled electromagnetic forces to achieve suspension, and self-excited vibration may occur due to the flexibility of the track. In this article, the harmonic balance method is applied to investigate the amplitude of the self-excited vibration, and it is found that the amplitude of the vibration depends on the voltage of the power supplier. Based on this observation, a vibration amplitude control method, which controls the amplitude of the vibration by adjusting the voltage of the power supplier, is proposed to attenuate the vibration. A PI controller is designed to control the amplitude of the vibration at a given level. The effectiveness of this method shows a good prospect for its application to commercial maglev systems. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Theoretical study on flow-induced vibration of a cylindrical weir due to fluid discharge

International Nuclear Information System (INIS)

Fujita, Katsuhisa; Ito, Tomohiro; Hirota, Kazuo; Kodama, Tetsuhiko

1994-01-01

In a FBR, the inside of the reactor vessel is cooled by liquid sodium. Liquid sodium is supplied to the upper plenum from its bottom and discharges over the top of the cylindrical weir down to the lower plenum. The weir is so thin in order to decrease the thermal stress on it that the fluid--structure interaction becomes predominant. A fluidelastic vibration of the weir due to fluid discharge was discovered in a French FBR. In this study, a theoretical model was developed on the ''fluid--elastic mode'' instability of a cylindrical weir due to fluid discharge from the upper plenum to the lower plenum. In the analysis, the fluctuation of both the discharge flow rate over a weir due to the vibration of the cylindrical shell and the pressure in the lower plenum due to fluid discharge were formulated. Instability criteria was derived from the added damping ratio due to fluid discharge using modal analysis. The natural modes and modal mass of the weir were obtained by the analysis using the FEM code taking the fluid - structure interaction into consideration. The theoretical instability range in terms of the fall height and the flow rate is compared with the experimental results. The theoretical values showed a good agreement with the experimental ones

Design of a one-chip board microcontrol unit for active vibration control of a naval ship mounting system

International Nuclear Information System (INIS)

Oh, Jong-Seok; Choi, Seung-Bok; Han, Young-Min; Nguyen, Vien-Quoc; Moon, Seok-Jun

2012-01-01

This work presents an experimental implementation of a user-tunable one-chip board microcontrol unit which is specifically designed for vibration control of the active mounting system for naval ships. The proposed mounting system consists of four active mounts supporting vibration-sensitive equipment. Each active mount constitutes a rubber element, an inertial mass and the piezostack actuator. It is designed for particular applications that require effective isolation performance against wide frequency ranges, such as naval ship equipment. After describing the configuration of the active mount, dynamic characteristics of the rubber element and the piezostack actuator are experimentally identified. Accordingly, the proposed mounting system is constructed and the governing equations of motion are formulated. In order to attenuate the unwanted vibrations transferred from the upper mass, a feedforward controller with fast Fourier algorithm is designed and experimentally realized using the one-chip microcontrol board which is specially made for this practical application. In order to evaluate the performance of the one-chip microcontrol unit, vibration control results of the proposed active mounting system are presented in the frequency domain. (technical note)

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.

Ship Vibrations

DEFF Research Database (Denmark)

Sørensen, Herman

1997-01-01

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

Vibrations measurement at the Embalse nuclear power plant's electrical generator

International Nuclear Information System (INIS)

Salomoni, R.C.; Belinco, C.G.; Pastorini, A.J.; Sacchi, M.A.

1987-01-01

After the modifications made at the Embalse nuclear power plant's electrical generator to reduce its vibration level produced by electromagnetic phenomena, it was necessary to perform measurements at the new levels, under different areas and power conditions. To this purpose, a work was performed jointly with the 'Vibrations Team' of the ANSALDO Company (the generator constructor) and the Hydrodynamic Assays Division under the coordination and supervision of the plant's electrical maintenance responsible. This paper includes the main results obtained and the instrumentation criteria and analysis performed. (Author)

Classification Trees and the Analysis of Helicopter Vibration Data

National Research Council Canada - National Science Library

Larson, Harold

1997-01-01

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

Metacognitive gimmicks and their use by upper level physics students

Science.gov (United States)

White, Gary; Sikorski, Tiffany-Rose; Landay, Justin

2017-01-01

We report on the initial phases of a study of three particular metacognitive gimmicks that upper-level physics students can use as a tool in their problem-solving kit, namely: checking units for consistency, discerning whether limiting cases match physical intuition, and computing numerical values for reasonable-ness. Students in a one semester Griffiths electromagnetism course at a small private urban university campus are asked to respond to explicit prompts that encourage adopting these three methods for checking answers to physics problems, especially those problems for which an algebraic expression is part of the final answer. We explore how, and to what extent, these students adopt these gimmicks, as well as the time development of their use. While the term ``gimmick'' carries with it some pejorative baggage, we feel it describes the essential nature of the pedagogical idea adequately in that it gets attention, is easy for the students to remember, and represents, albeit perhaps in a surface way, some key ideas about which professional physicists care.

Effects of vibration frequency on vibration-assisted nano-scratch process of mono-crystalline copper via molecular dynamics simulation

Directory of Open Access Journals (Sweden)

Bo Zhu

2016-03-01

Full Text Available It has always been a critical issue to understand the material removal behavior of Vibration-Assisted Machining (VAM, especially on atomic level. To find out the effects of vibration frequency on material removal response, a three-dimensional molecular dynamics (MD model has been established in this research to investigate the effects of scratched groove, crystal defects on the surface quality, comparing with the Von Mises shear strain and tangential force in simulations during nano-scratching process. Comparisons are made among the results of simulations from different vibration frequency with the same scratching feed, depth, amplitude and crystal orientation. Copper potential in this simulation is Embedded-Atom Method (EAM potential. Interaction between copper and carbon atoms is Morse potential. Simulational results show that higher frequency can make groove smoother. Simulation with high frequency creates more dislocations to improve the machinability of copper specimen. The changing frequency does not have evident effects on Von Mises shear strain. Higher frequency can decrease the tangential force to reduce the consumption of cutting energy and tool wear. In conclusion, higher vibration frequency in VAM on mono-crystalline copper has positive effects on surface finish, machinablility and tool wear reduction.

Effects of vibration frequency on vibration-assisted nano-scratch process of mono-crystalline copper via molecular dynamics simulation

Energy Technology Data Exchange (ETDEWEB)

Zhu, Bo; Zhao, Hongwei, E-mail: hwzhao@jlu.edu.cn, E-mail: khl69@163.com; Zhao, Dan; Zhang, Peng; Yang, Yihan; Han, Lei [School of Mechanical Science and Engineering, Jilin University, 5988 Renmin Street, Changchun, Jilin 130025 (China); Kui, Hailin, E-mail: hwzhao@jlu.edu.cn, E-mail: khl69@163.com [School of Transportation, Jilin University, 5988 Renmin Street, Changchun, Jilin 130025 (China)

2016-03-15

It has always been a critical issue to understand the material removal behavior of Vibration-Assisted Machining (VAM), especially on atomic level. To find out the effects of vibration frequency on material removal response, a three-dimensional molecular dynamics (MD) model has been established in this research to investigate the effects of scratched groove, crystal defects on the surface quality, comparing with the Von Mises shear strain and tangential force in simulations during nano-scratching process. Comparisons are made among the results of simulations from different vibration frequency with the same scratching feed, depth, amplitude and crystal orientation. Copper potential in this simulation is Embedded-Atom Method (EAM) potential. Interaction between copper and carbon atoms is Morse potential. Simulational results show that higher frequency can make groove smoother. Simulation with high frequency creates more dislocations to improve the machinability of copper specimen. The changing frequency does not have evident effects on Von Mises shear strain. Higher frequency can decrease the tangential force to reduce the consumption of cutting energy and tool wear. In conclusion, higher vibration frequency in VAM on mono-crystalline copper has positive effects on surface finish, machinablility and tool wear reduction.

Evaluation of vibration and vibration fatigue life for small bore pipe in nuclear power plants

International Nuclear Information System (INIS)

Wang Zhaoxi; Xue Fei; Gong Mingxiang; Ti Wenxin; Lin Lei; Liu Peng

2011-01-01

The assessment method of the steady state vibration and vibration fatigue life of the small bore pipe in the supporting system of the nuclear power plants is proposed according to the ASME-OM3 and EDF evaluation methods. The GGR supporting pipe system vibration is evaluated with this method. The evaluation process includes the filtration of inborn sensitivity, visual inspection, vibration tests, allowable vibration effective velocity calculation and vibration stress calculation. With the allowable vibration effective velocity calculated and the vibration velocity calculated according to the acceleration data tested, the filtrations are performed. The vibration stress at the welding coat is calculated with the spectrum method and compared with the allowable value. The response of the stress is calculated with the transient dynamic method, with which the fatigue life is evaluated with the Miners linear accumulation model. The vibration stress calculated with the spectrum method exceeds the allowable value, while the fatigue life calculated from the transient dynamic method is larger than the designed life with a big safety margin. (authors)

Do Activity Level Outcome Measures Commonly Used in Neurological Practice Assess Upper-Limb Movement Quality?

Science.gov (United States)

Demers, Marika; Levin, Mindy F

2017-07-01

Movement is described in terms of task-related end point characteristics in external space and movement quality (joint rotations in body space). Assessment of upper-limb (UL) movement quality can assist therapists in designing effective treatment approaches for retraining lost motor elements and provide more detailed measurements of UL motor improvements over time. To determine the extent to which current activity level outcome measures used in neurological practice assess UL movement quality. Outcome measures assessing arm/hand function at the International Classification of Function activity level recommended by neurological clinical practice guidelines were reviewed. Measures assessing the UL as part of a general mobility assessment, those strictly evaluating body function/structure or participation, and paediatric measures were excluded. In all, 15 activity level outcome measures were identified; 9 measures assess how movement is performed by measuring either end point characteristics or movement quality. However, except for the Reaching Performance Scale for Stroke and the Motor Evaluation Scale for Upper Extremity in Stroke Patients, these measures only account for deficits indirectly by giving a partial score if movements are slower or if the person experiences difficulties. Six outcome measures neither assess any parameters related to movement quality, nor distinguish between improvements resulting from motor compensation or recovery of desired movement strategies. Current activity measures may not distinguish recovery from compensation and adequately track changes in movement quality over time. Movement quality may be incorporated into clinical assessment using observational kinematics with or without low-cost motion tracking technology.

On noise, traffic and factory vibrations in Akita city; Akitashi ni okeru soon oyobi kotsu kojo shindo ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Nogoshi, M; Kikuchi, T; Morino, T; Sannohe, M [Akita University, Akita (Japan). College of Education

1996-05-01

Noise and vibration were measured in Akita City. In 1994, noise and traffic-caused vibration were measured along the trunk lines and other roads across the entire Akita City area. In 1995, the effort centered on the Ibarashima manufacturing quarters, the important source of noise and vibration in Akita city. The general-purpose noise meter LA-220S was used to measure noise and the vibration level meter VR-5100 was used to measure vibration. The results of noise measurement carried out at 122 points in Akita City indicated that the noise level was high along Route 7, Route 13, and the southern line belonging to the newly built national highway, marking the highest of approximately 74dB. As compared with the measurement made in 1968, the value was higher by 3-13dB. A roughly similar trend was seen in vibration. The noise level measurement of 1995 accomplished at 100 points in the vicinity of Ibarashima district indicated that the factories were responsible for high levels of noise and vibration. It was found that the levels lowered in proportion to the increase in the distance from the factories. 11 figs., 1 tab.

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

Evaluation of human-induced vibration of continuous footbridges

Directory of Open Access Journals (Sweden)

El-Robaa Ahmed

2015-01-01

Full Text Available With the development of construction materials and the introduction of high strength steel and concrete, the human-induced vibration became a dominant criterion for the design of pedestrian bridges. Currently, longer spans and lightweight bridges have been comprised in most of design trends. This leads to lower the natural frequencies of the system which have a great effect on the dynamic performance of bridges subjected to human activities. Although the design of steel footbridges could reach the optimum level of design in terms of strength criterion, it might not reach the acceptance level for vibration condition. This will enforce the designer to choose section profiles with higher inertia to enhance stiffness of the whole system. This paper presents an overall assessment for floor vibration problem due to pedestrian induced vertical forces on continuous composite footbridges. The footfall method presented by concrete centre “CCIP-016” is adopted in this study to evaluate the response factor and acceleration of pedestrian bridges using a FEA software package “Robot Structural Analysis”.

Vibration characteristics of a vertical round tube according to heat transfer regimes

International Nuclear Information System (INIS)

Lee, Yong Ho; Kim, Dae Hun; Chang, Soon Heung; Baek, Won Pil

2001-01-01

This paper presents the results of an experimental work on the effects of boiling heat transfer regimes on the vibration. the experiment has been performed using an electrically heated veritcal round tube through which water flows at atmospheric pressure. Vibration characteristics of the heated tube are changed significantly by heat transfer regimes and flow patterns. For single-phase liquid convection, the rod vibrations are negligible. However, On the beginning of subcooled nucleate boiling at tube exit, vibration level becomes very large. As bubble departure is occurred at the nucleation site of heated surface, the vibration decrease to saturated boiling region where thermal equilibrium quality becomes 0.0 at tube exit. In saturated boiling region, vibration amplitude increase with exit quality up to certain maximum value then decreases. At liquid film dryout condition, vibration could be regarded as negligible, however, these results cannot be extended to DNB-type CHF mechanism. Frequency analysis results of vibration signals suggested that excitation sources be different with heat transfer regimes. This study would contribute to improve the understanding of the relationship between boiling heat transfer and FIV

Molecular equilibrium structures from experimental rotational constants and calculated vibration-rotation interaction constants

DEFF Research Database (Denmark)

Pawlowski, F; Jorgensen, P; Olsen, Jeppe

2002-01-01

A detailed study is carried out of the accuracy of molecular equilibrium geometries obtained from least-squares fits involving experimental rotational constants B(0) and sums of ab initio vibration-rotation interaction constants alpha(r)(B). The vibration-rotation interaction constants have been...... calculated for 18 single-configuration dominated molecules containing hydrogen and first-row atoms at various standard levels of ab initio theory. Comparisons with the experimental data and tests for the internal consistency of the calculations show that the equilibrium structures generated using Hartree......-Fock vibration-rotation interaction constants have an accuracy similar to that obtained by a direct minimization of the CCSD(T) energy. The most accurate vibration-rotation interaction constants are those calculated at the CCSD(T)/cc-pVQZ level. The equilibrium bond distances determined from these interaction...

Diagnostics of hand-arm system disorders in workers who use vibrating tools.

Science.gov (United States)

Gemne, G

1997-02-01

A hand-arm vibration syndrome occurs in some workers who use hand held vibrating tools. It is recognised to consist of white fingers, diffusely distributed finger neuropathy, pain in the arm and hand, and a small excess risk of osteoarthrosis from percussion to the wrist and elbow. Carpal tunnel syndrome is mainly due to ergonomic factors other than vibration, but certain factors related to vibration may contribute to its development. A decrease in muscle power induced by vibration, and excessive hearing deficit have been postulated. The assessment of a disorder suspected of being induced by vibration includes deciding whether there is a disorder and, if so, whether the symptoms can be caused by vibration. To decide whether the symptoms can be caused by vibration epidemiological documentation and pathogenically reasonable theories must exist. A causal diagnosis finally requires and epidemiological decision whether or not the factual exposure has elicited the patient's symptoms. Epidemiological data on the quantitative association between vibration and excessive risks of white fingers and diffusely distributed neuropathy are incomplete. The symptomatic diagnosis of white fingers is still mainly based on anamnestic information. Available laboratory tests are incapable of grading the severity of individual cases. Recording the finger systolic blood pressure during cold provocation is a method of symptomatic diagnosis with reasonable levels of specificity, sensitivity, and predictive value. For diffusely distributed neuropathy these levels are lower than desired. Electrodiagnostic tests for carpal tunnel syndrome have sufficient validity. Proper exposure evaluation must be based on an appreciation of the character of the vibration as well as effective duration and intermittency. If this is not taken into account, the number of hours of exposure and intensity of vibration are likely to be non-commensurable variables, and the simple product of them is a questionable dose

Vibration insensitive interferometry

Science.gov (United States)

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

2017-11-01

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

Retrospective Review of Air Transportation Use for Upper Extremity Amputations at a Level-1 Trauma Center.

Science.gov (United States)

Grantham, W Jeffrey; To, Philip; Watson, Jeffry T; Brywczynski, Jeremy; Lee, Donald H

2016-08-01

Air transportation to tertiary care centers of patients with upper extremity amputations has been utilized in hopes of reducing the time to potential replantation; however, this mode of transportation is expensive and not all patients will undergo replantation. The purpose of this study is to review the appropriateness and cost of air transportation in upper extremity amputations. Consecutive patients transported by aircraft with upper extremity amputations in a 7-year period at a level-1 trauma center were retrospectively reviewed. The distance traveled was recorded, along with the times of the injury, referral, transportation duration, arrival, and start of the operation. The results of the transfer were defined as replantation or revision amputation. Overall, 47 patients were identified with 43 patients going to the operating room, but only 14 patients (30%) undergoing replantation. Patients arrived at the tertiary hand surgery center with a mean time of 182.3 minutes following the injury, which includes 105.2 minutes of transportation time. The average distance traveled was 105.4 miles (range, 22-353 miles). The time before surgery of those who underwent replantation was 154.6 minutes. The average cost of transportation was $20,482. Air transportation for isolated upper extremity amputations is costly and is not usually the determining factor for replantation. The type of injury and patients' expectations often dictate the outcome, and these may be better determined at the time of referral with use of telecommunication photos, discussion with a hand surgeon, and patient counseling. III.

Integrating Wind Profiling Radars and Radiosonde Observations with Model Point Data to Develop a Decision Support Tool to Assess Upper-Level Winds for Space Launch

Science.gov (United States)

Bauman, William H., III; Flinn, Clay

2013-01-01

On the day of launch, the 45th Weather Squadron (45 WS) Launch Weather Officers (LWOs) monitor the upper-level winds for their launch customers. During launch operations, the payload/launch team sometimes asks the LWOs if they expect the upper-level winds to change during the countdown. The LWOs used numerical weather prediction model point forecasts to provide the information, but did not have the capability to quickly retrieve or adequately display the upper-level observations and compare them directly in the same display to the model point forecasts to help them determine which model performed the best. The LWOs requested the Applied Meteorology Unit (AMU) develop a graphical user interface (GUI) that will plot upper-level wind speed and direction observations from the Cape Canaveral Air Force Station (CCAFS) Automated Meteorological Profiling System (AMPS) rawinsondes with point forecast wind profiles from the National Centers for Environmental Prediction (NCEP) North American Mesoscale (NAM), Rapid Refresh (RAP) and Global Forecast System (GFS) models to assess the performance of these models. The AMU suggested adding observations from the NASA 50 MHz wind profiler and one of the US Air Force 915 MHz wind profilers, both located near the Kennedy Space Center (KSC) Shuttle Landing Facility, to supplement the AMPS observations with more frequent upper-level profiles. Figure 1 shows a map of KSC/CCAFS with the locations of the observation sites and the model point forecasts.

Analysis and simulation of centrifugal pendulum vibration absorbers

OpenAIRE

Smith, Emma

2015-01-01

When environmental laws are constricted and downsizing of engines has become the reality of the vehicle industry, there needs to be a solution for the rise in torsion vibrations in the drivetrain. These increased levels of torsion vibrations are mostly due to excitations from the firing pulses, which in turn have become increased due to higher cylinder pressures. One of the solutions for further dampening the system is to add a centrifugal pendulum absorber to the flywheel, and predicting the...

Molecular Origin of the Vibrational Structure of Ice Ih.

Science.gov (United States)

Moberg, Daniel R; Straight, Shelby C; Knight, Christopher; Paesani, Francesco

2017-06-15

An unambiguous assignment of the vibrational spectra of ice I h remains a matter of debate. This study demonstrates that an accurate representation of many-body interactions between water molecules, combined with an explicit treatment of nuclear quantum effects through many-body molecular dynamics (MB-MD), leads to a unified interpretation of the vibrational spectra of ice I h in terms of the structure and dynamics of the underlying hydrogen-bond network. All features of the infrared and Raman spectra in the OH stretching region can be unambiguously assigned by taking into account both the symmetry and the delocalized nature of the lattice vibrations as well as the local electrostatic environment experienced by each water molecule within the crystal. The high level of agreement with experiment raises prospects for predictive MB-MD simulations that, complementing analogous measurements, will provide molecular-level insights into fundamental processes taking place in bulk ice and on ice surfaces under different thermodynamic conditions.

Vibration Analysis of a Residential Building

Directory of Open Access Journals (Sweden)

Sampaio Regina Augusta

2015-01-01

Full Text Available The aim of this paper is to present the results of a study regarding vibration problems in a 17 storey residential building during pile driving in its vicinity. The structural design of the building was checked according to the Brazilian standards NBR6118 and NBR6123, and using commercial finite element software. An experimental analysis was also carried out using low frequency piezo-accelerometers attached to the building structure. Structure vibrations were recorded under ambient conditions. Four monitoring tests were performed on different days. The objective of the first monitoring test was an experimental modal analysis. To obtain de modal parameters, data was processed in the commercial software ARTEMIS employing two methods: the Stochastic Subspace Identification and the Frequency Domain Decomposition. Human comfort was investigated considering the International Standard ISO 2631. The Portuguese standard, NP2074, was also used as a reference, since it aims to limit the adverse effects of vibrations in structures caused by pile driving in the vicinity of the structure. The carried out experimental tests have shown that, according to ISO2301, the measure vibration levels are above the acceptance limits. However, velocity peaks are below the limits established by NP2074. It was concluded that, although the structure has adequate capacity to resist internal forces according to normative criteria, it has low horizontal stiffness, which could be verified by observing the vibration frequencies and mode shapes obtained with the finite element models, and its similarity with the experimental results. Thus, the analyses indicate the occurrence of discomfort by the residents.

Baseline blood Pb levels of black-necked stilts on the upper Texas coast

Science.gov (United States)

Riecke, Thomas V.; Conway, Warren C.; Haukos, David A.; Moon, Jena A.; Comer, Christopher E.

2015-01-01

There are no known biological requirements for lead (Pb), and elevated Pb levels in birds can cause a variety of sub-lethal effects and mortality. Historic and current levels of Pb in mottled ducks (Anas fulvigula) suggest that environmental sources of Pb remain available on the upper Texas coast. Because of potential risks of Pb exposure among coexisting marsh birds, black-necked stilt (Himantopus mexicanus) blood Pb concentrations were measured during the breeding season. Almost 80 % (n = 120) of 152 sampled stilts exceeded the background threshold (>20 μg/dL) for Pb exposure. However, blood Pb concentrations did not vary by age or gender, and toxic or potentially lethal concentrations were rare (study suggest the presence of readily bioavailable sources of Pb, although potential impacts on local stilt populations remain unclear.

Study on vibration characteristics of the shaft system for a dredging pump based on FEM

International Nuclear Information System (INIS)

Zhai, L M; Liu, X; He, L Y; Wang, Z W; Qin, L; Liu, C Y; He, Y

2012-01-01

The dynamic characteristics of the shaft system for a dredging pump were studied with the Finite Element Method (FEM) by SAMCEF ROTOR. At first, the influence of the fluid-solid coupling interaction of mud water and impeller, water sealing and pump shaft on the lateral critical speeds were analyzed. The results indicated that the mud water must be taken into consideration, while the water sealing need not to. Then the effects of radial and thrust rolling bearings on the lateral critical speeds were discussed, which shows that the radial bearing close to the impeller has greatest impact on the 1st order critical speed. At last, the upper and lower limits of the critical speeds of lateral, axial and torsional vibration were calculated. The rated speed of the dredging pump was far less than the predicted critical speed, which can ensure the safe operation of the unit. Each vibration mode is also shown in this paper. This dynamic analysis method offers some reference value on the research of vibration and stability of the shaft system in dredging pump.

Gearbox tooth cut fault diagnostics using acoustic emission and vibration sensors--a comparative study.

Science.gov (United States)

Qu, Yongzhi; He, David; Yoon, Jae; Van Hecke, Brandon; Bechhoefer, Eric; Zhu, Junda

2014-01-14

In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance.

[Carpal canal ultrasound examination in patients with mild hand-arm vibration disease].

Science.gov (United States)

Liu, Y Z; Ye, Z H; Yang, W L; Zhu, J X; Lu, Q J; Su, W L

2016-08-20

Objective: To investigate the clinical value of ultrasound examination of carpal canal structure in patients with mild hand-arm vibration disease. Methods: A total of 29 patients (58 wrists) with mild hand-arm vibration disease who were treated in Shenzhen Prevention and Treatment Center for Occupational Diseases from May to December, 2015 were enrolled as observation group, and 20 healthy volunteers (40 wrists) were enrolled as the control group. Color Doppler ultrasound was used to observe the morphology and echo of the median nerve in the carpal canal and 9 muscle tendons and transverse carpal ligament. The thickness of transverse carpal ligament and diameter of the median nerve at the level of the hamulus of hamate bone were measured, as well as the cross-sectional area of the median nerve at the level of pisiform bone. Results: In the 29 patients with hand-arm vibration disease patients in the observation group, 8 experienced entrapment of the median nerve in the carpal canal, among whom 5 had entrapment in both wrists; there were 13 wrists (23%) with nerve entrapment and 45 wrists (77%) without nerve entrapment. Compared with the control group, the patients with hand-arm vibration disease and nerve entrapment in the observation group showed significant thickening of the transverse carpal ligament at the level of the hamulus of hamate bone and a significant increase in the cross-sectional area of the median nerve at the level of pisiform bone ( P 0.05) . Conclusion: Ultrasound examination can clearly show the radiological changes of carpal canal contents in patients with mild hand-arm vibration disease and has a certain diagnostic value in nerve damage in patients with hand-arm vibration disease.

Vibration monitoring and fault diagnostics of a thermal power plant

International Nuclear Information System (INIS)

Hafeez, T.; Ghani, R.; Chohan, G.Y.; Amir, M.

2003-01-01

A thermal power plant was monitored from HP-turbine to the generator end. The vibration data at different plant locations was obtained with the help of a data collector/analyzer. The spectra of-all locations generate the symptoms for different problems of moderate and high vibration levels like bent shaft, misalignment in the exciter rotor and three couplings, mechanical looseness on generator and exciter sides. The possible causes of these faults are discussed on the basis of presented vibration spectra in this paper. The faults were later on rectified on the basis of this diagnostics. (author)

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.)

Selective excitation of a vibrational level within the electronic ground state of a polyatomic molecule with ultra short pulses

CSIR Research Space (South Africa)

De Clercq, L

2010-09-01

Full Text Available al lbl d i I e I e dt ω ωρ ρ ρ − = − = −∑h (1) where, , .a b a bω ω ω= − , (2) ρab gives the elements of the density matrix, ωa the frequencies... of the individual vibrational levels, and Iab the matrix elements of the interaction Hamiltonian [2] which include the detailed time dependence of the shaped femtosecond pulse. 2. Simulation results A transform limited 150 femtosecond laser pulse with a...

Tendon vibration attenuates superficial venous vessel response of the resting limb during static arm exercise

Directory of Open Access Journals (Sweden)

Ooue Anna

2012-11-01

Full Text Available Abstract Background The superficial vein of the resting limb constricts sympathetically during exercise. Central command is the one of the neural mechanisms that controls the cardiovascular response to exercise. However, it is not clear whether central command contributes to venous vessel response during exercise. Tendon vibration during static elbow flexion causes primary muscle spindle afferents, such that a lower central command is required to achieve a given force without altering muscle force. The purpose of this study was therefore to investigate whether a reduction in central command during static exercise with tendon vibration influences the superficial venous vessel response in the resting limb. Methods Eleven subjects performed static elbow flexion at 35% of maximal voluntary contraction with (EX + VIB and without (EX vibration of the biceps brachii tendon. The heart rate, mean arterial pressure, and rating of perceived exertion (RPE in overall and exercising muscle were measured. The cross-sectional area (CSAvein and blood velocity of the basilic vein in the resting upper arm were assessed by ultrasound, and blood flow (BFvein was calculated using both variables. Results Muscle tension during exercise was similar between EX and EX + VIB. However, RPEs at EX + VIB were lower than those at EX (P P vein in the resting limb at EX decreased during exercise from baseline (P vein at EX + VIB did not change during exercise. CSAvein during exercise at EX was smaller than that at EX + VIB (P vein did not change during the protocol under either condition. The decreases in circulatory response and RPEs during EX + VIB, despite identical muscle tension, showed that activation of central command was less during EX + VIB than during EX. Abolishment of the decrease in CSAvein during exercise at EX + VIB may thus have been caused by a lower level of central command at EX + VIB rather than EX. Conclusion Diminished central command induced by tendon

Muscular forearm activation in hand-grip tasks with superimposition of mechanical vibrations.

Science.gov (United States)

Fattorini, L; Tirabasso, A; Lunghi, A; Di Giovanni, R; Sacco, F; Marchetti, E

2016-02-01

The purpose of this paper is to evaluate the muscular activation of the forearm, with or without vibration stimuli at different frequencies while performing a grip tasks of 45s at various level of exerted force. In 16 individuals, 9 females and 7 males, the surface electromyogram (EMG) of extensor carpi radialis longus and the flexor carpi ulnari muscles were assessed. At a short latency from onset EMG, RMS and the level of MU synchronization were assessed to evaluate the muscular adaptations. Whilst a trend of decay of EMG Median frequency (MDFd) was employed as an index of muscular fatigue. Muscular tasks consists of the grip of an instrumented handle at a force level of 20%, 30%, 40%, 60% of the maximum voluntary force. Vibration was supplied by a shaker to the hand in mono-frequential waves at 20, 30, 33 and 40Hz. In relation to EMG, RMS and MU synchronization, the muscular activation does not seem to change with the superimposition of the mechanical vibrations, on the contrary a lower MDFd was observed at 33Hz than in absence of vibration. This suggests an early muscular fatigue induced by vibration due to the fact that 33Hz is a resonance frequency for the hand-arm system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Current pathophysiological views on vibration-induced Raynaud's phenomenon.

Science.gov (United States)

Stoyneva, Z; Lyapina, M; Tzvetkov, D; Vodenicharov, E

2003-03-01

This review attempts to summarize and discuss contemporary pathogenetic views on vibration-induced Raynaud's phenomenon assuming its multifactorial etiology. An increase in central and peripheral sympathetic nervous activity is discussed based on different physiological indicators of autonomic dysfunction and sympathetic hyperactivity. Local acral vasodysregulation is considered. Receptor and nerve endings dysfunction presented with predominance of alpha(2)-receptor function in the digital arteries and neuronal loss in those digital cutaneous perivascular nerves containing calcitonin gene-related peptide result in deficiency of endogenous release of this powerful vasodilator. Endothelial damage and dysregulation induced by vibration and increased shear stresses are demonstrated by the elevated plasma level of thrombomodulin and of von Willebrand factor and reduced endothelium-dependent vasodilator responses. The concentrations of endothelin-1 are high, the highest being in most advanced stages. Decreased plasma thiol level, indicating increased production and activity of free radicals, contribute to vasospastic paroxysms in vibration white finger patients. Dysbalance of local vasoactive factors with opposing effects on vascular smooth muscle like endothelin and nitric oxide, endothelin and calcitonin gene-related peptide, nitric oxide and superoxide anion are discussed. Disturbed smooth muscle response is supposed. Changes in hemostasis, fibrinolysis and hemorrheology, activation of blood cells with erythrocyte hyperaggregation and red cell hypodeformability, platelet aggregation with increased release of vasoconstricting thromboxane A(2) and serotonin as well as leukocyte activation, entrapment within capillaries and post-capillary venules and increased reactive oxygen species and lysosomal lytic enzymes release might also contribute to digital vasospasms and tissue damage. Elevated soluble intercellular adhesion molecule-1 levels involved in the adherence of

Investigation of the correlation between noise and vibration characteristics and unsteady flow in a circulator pump

Energy Technology Data Exchange (ETDEWEB)

Wu, Denghao; Ren, Yun; Mou, Jiegang; Gu, Yunqing [Zhejiang University of Technology, Hangzhou (China)

2017-05-15

Circulator pumps have wide engineering applications but the acoustics, vibration and unsteady flow structures of the circulator pump are still not fully understood. We investigated the noise and vibration characteristics and unsteady flow structures in a circulator pump at different flow rates. Three-dimensional, unsteady RANS equations were solved on high-quality structured meshes with SST k-ω turbulence model numerically. Measurements were made in a semi-anechoic chamber to get an overview of noise and vibration level of a pump at different flow rates. The 1/3 octave-band filter technique was applied to obtain the explicit frequency spectra of sound, pressure fluctuations and vibration signals and their principal frequencies were identified successfully. The air-borne noise level of the designed condition is lower than that of the off-design conditions, and the highest sound pressure level is found at part-load condition. The acoustic emission from the pump is mainly caused by unsteady flow structures and pressure fluctuations. In addition, both the link between air- borne noise and pressure fluctuation, and the correlation between vibration and unsteady hydrodynamic forces, were quantitatively examined and verified. This work offers good data to understand noise and vibration characteristics of circulator pumps and the relationships among the noise, vibration and unsteady flow structures.

Bubbling behavior of a fluidized bed of fine particles caused by vibration-induced air inflow.

Science.gov (United States)

Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi

2013-01-01

We demonstrate that a vibration-induced air inflow can cause vigorous bubbling in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of bubbles that rise and eventually burst at the top surface of the powder bed. A negative pressure is created below the rising bubbles. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously bubbling fluidized bed that does not require the use of an external air supply system.

Signal Processing Methods for Removing the Effects of Whole Body Vibration upon Speech

Science.gov (United States)

Bitner, Rachel M.; Begault, Durand R.

2014-01-01

Humans may be exposed to whole-body vibration in environments where clear speech communications are crucial, particularly during the launch phases of space flight and in high-performance aircraft. Prior research has shown that high levels of vibration cause a decrease in speech intelligibility. However, the effects of whole-body vibration upon speech are not well understood, and no attempt has been made to restore speech distorted by whole-body vibration. In this paper, a model for speech under whole-body vibration is proposed and a method to remove its effect is described. The method described reduces the perceptual effects of vibration, yields higher ASR accuracy scores, and may significantly improve intelligibility. Possible applications include incorporation within communication systems to improve radio-communication systems in environments such a spaceflight, aviation, or off-road vehicle operations.

Flow induced vibration studies on PFBR control plug components

Energy Technology Data Exchange (ETDEWEB)

Prakash, V., E-mail: prakash@igcar.gov.in [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India); Kumar, P. Anup; Anandaraj, M.; Thirumalai, M.; Anandbabu, C.; Rajan, K.K. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India)

2012-09-15

Highlights: Black-Right-Pointing-Pointer Flow induced vibration studies on Prototype Fast Breeder Reactor control plug model carried out. Black-Right-Pointing-Pointer Velocity similitude was followed for the study. Black-Right-Pointing-Pointer Frequencies and amplitude of vibrations of various control plug components measured. Black-Right-Pointing-Pointer Overall values of vibration are well within permissible limits. - Abstract: The construction of Prototype Fast Breeder Reactor (PFBR), a 500 MWe liquid sodium cooled reactor, is in progress at Kalpakkam in India. Control plug (CP) is located right above the core subassemblies in the hot pool. Control plug is an important component as many of the critical reactor parameters are sensed and controlled by the components housed in the control plug assembly. In PFBR primary circuit, components are basically thin walled, slender shells with diameter to thickness ratio ranging from 100 to 650. These components are prone to flow induced vibrations. The existence of free liquid (sodium) surfaces, which is the source of sloshing phenomenon and the operation of primary sodium pump in the primary pool are other potential sources of vibration of reactor components. Control plug is a hollow cylindrical shell structure and provides passages and support for 12 absorber rod drive mechanisms (ARDM) which consists of 9 control and safety rods and 3 diverse safety rods, 210 thermo wells to measure the sodium temperature at the exit of various fuel subassemblies, three failed fuel localization modules (FFLM) and acoustic detectors. It consists of a core cover plate (CCP), which forms the bottom end, two intermediate supports plate, i.e. lower stay plate (LSP) and upper stay plate (USP) and an outer shell. The CCP is located at a distance of 1.3 m from the core top. With such a gap, there will be long free hanging length of the thermocouple sleeves, Delayed neutron detector (DND) sampling tubes and ARDM shroud tubes and hence they are

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.

Measurement of ground and nearby building vibration and noise induced by trains in a metro depot.

Science.gov (United States)

Zou, Chao; Wang, Yimin; Wang, Peng; Guo, Jixing

2015-12-01

Metro depots are where subway trains are parked and where maintenance is carried out. They usually occupy the largest ground areas in metro projects. Due to land utilization problems, Chinese cities have begun to develop over-track buildings above metro depots for people's life and work. The frequently moving trains, when going into and out of metro depots, can cause excessive vibration and noise to over-track buildings and adversely affect the living quality of the building occupants. Considering the current need of reliable experimental data for the construction of metro depots, field measurements of vibration and noise on the ground and inside a nearby 3-story building subjected to moving subway trains were conducted in a metro depot at Guangzhou, China. The amplitudes and frequency contents of velocity levels were quantified and compared. The composite A-weighted equivalent sound levels and maximum sound levels were captured. The predicted models for vibration and noise of metro depot were proposed based on existing models and verified. It was found that the vertical vibrations were significantly greater than the horizontal vibrations on the ground and inside the building near the testing line. While at the throat area, the horizontal vibrations near the curved track were remarkably greater than the vertical vibrations. The attenuation of the vibrations with frequencies above 50 Hz was larger than the ones below 50 Hz, and the frequencies of vibration transmitting to adjacent buildings were mainly within 10-50 Hz. The largest equivalent sound level generated in the throat area was smaller than the testing line one, but the instantaneous maximum sound level induced by wheels squeal, contact between wheels and rail joints as well as turnout was close to or even greater than the testing line one. The predicted models gave a first estimation for design and assessment of newly built metro depots. Copyright © 2015 Elsevier B.V. All rights reserved.

Vibrational Mode-Specific Autodetachment and Coupling of CH2CN-

Science.gov (United States)

Lyle, Justin; Mabbs, Richard

2017-06-01

The Cyanomethyl Anion, CH_{2}CN-, and neutral radical have been studied extensively, with several findings of autodetachment about the totally symmetric transition, as well as high resolution experiments revealing symmetrically forbidden and weak vibrational features. We report photoelectron spectra using the Velocity-Mapped Imaging Technique in 1-2 \\wn increments over a range of 13460 to 15384 \\wn that has not been previously examined. These spectra include excitation of the ground state cyanomethyl anion into the direct detachment thresholds of previously reported vibrational modes for the neutral radical. Significant variations from Franck-Condon behavior were observed in the branching ratios for resolved vibrational features for excitation in the vicinity of the thresholds involving the νb{3} and νb{5} modes. These are consistent with autodetachment from rovibrational levels of a dipole bound state acting as a resonance in the detachment continuum. The autodetachment channels involve single changes in vibrational quantum number, consistent with the vibrational propensity rule but in some cases reveal relaxation to a different vibrational mode indicating coupling between the modes and/or a breakdown of the normal mode approximation.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-04-24

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

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

Modelling of magnetostriction of transformer magnetic core for vibration analysis

Science.gov (United States)

Marks, Janis; Vitolina, Sandra

2017-12-01

Magnetostriction is a phenomenon occurring in transformer core in normal operation mode. Yet in time, it can cause the delamination of magnetic core resulting in higher level of vibrations that are measured on the surface of transformer tank during diagnostic tests. The aim of this paper is to create a model for evaluating elastic deformations in magnetic core that can be used for power transformers with intensive vibrations in order to eliminate magnetostriction as a their cause. Description of the developed model in Matlab and COMSOL software is provided including restrictions concerning geometry and properties of materials, and the results of performed research on magnetic core anisotropy are provided. As a case study modelling of magnetostriction for 5-legged 200 MVA power transformer with the rated voltage of 13.8/137kV is conducted, based on which comparative analysis of vibration levels and elastic deformations is performed.

Modelling of magnetostriction of transformer magnetic core for vibration analysis

Directory of Open Access Journals (Sweden)

Marks Janis

2017-12-01

Full Text Available Magnetostriction is a phenomenon occurring in transformer core in normal operation mode. Yet in time, it can cause the delamination of magnetic core resulting in higher level of vibrations that are measured on the surface of transformer tank during diagnostic tests. The aim of this paper is to create a model for evaluating elastic deformations in magnetic core that can be used for power transformers with intensive vibrations in order to eliminate magnetostriction as a their cause. Description of the developed model in Matlab and COMSOL software is provided including restrictions concerning geometry and properties of materials, and the results of performed research on magnetic core anisotropy are provided. As a case study modelling of magnetostriction for 5-legged 200 MVA power transformer with the rated voltage of 13.8/137kV is conducted, based on which comparative analysis of vibration levels and elastic deformations is performed.

Oncoplastic Surgery for Upper/Upper Inner Quadrant Breast Cancer.

Science.gov (United States)

Lin, Joseph; Chen, Dar-Ren; Wang, Yu-Fen; Lai, Hung-Wen

2016-01-01

Tumors located in the upper/upper inner quadrant of the breast warrant more attention. A small lesion relative to the size of breast in this location may be resolved by performing a level I oncoplastic technique. However, a wide excision may significantly reduce the overall quality of the breast shape by distorting the visible breast line. From June 2012 to April 2015, 36 patients with breast cancer located in the upper/upper inner quadrant underwent breast-conservation surgery with matrix rotation mammoplasty. According to the size and location of the tumor relative to the nipple-areola complex, 11 patients underwent matrix rotation with periareolar de-epithelialization (donut group) and the other 25 underwent matrix rotation only (non-donut group). The cosmetic results were self-assessed by questionnaires. The average weights of the excised breast lumps in the donut and non-donut groups were 104.1 and 84.5 g, respectively. During the 3-year follow-up period, local recurrence was observed in one case and was managed with nipple-sparing mastectomy followed by breast reconstruction with prosthetic implants. In total, 31 patients (88.6%) ranked their postoperative result as either acceptable or satisfactory. The treated breasts were also self-evaluated by 27 patients (77.1%) to be nearly identical to or just slightly different from the untreated side. Matrix rotation is an easy breast-preserving technique for treating breast cancer located in the upper/upper inner quadrant of the breast that requires a relatively wide excision. With this technique, a larger breast tumor could be removed without compromising the breast appearance.

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.

Customized DSP-based vibration measurement for wind turbines

Energy Technology Data Exchange (ETDEWEB)

LaWhite, N.E.; Cohn, K.E. [Second Wind Inc., Somerville, MA (United States)

1996-12-31

As part of its Advanced Distributed Monitoring System (ADMS) project funded by NREL, Second Wind Inc. is developing a new vibration measurement system for use with wind turbines. The system uses low-cost accelerometers originally designed for automobile airbag crash-detection coupled with new software executed on a Digital Signal Processor (DSP) device. The system is envisioned as a means to monitor the mechanical {open_quotes}health{close_quotes} of the wind turbine over its lifetime. In addition the system holds promise as a customized emergency vibration detector. The two goals are very different and it is expected that different software programs will be executed for each function. While a fast Fourier transform (FFT) signature under given operating conditions can yield much information regarding turbine condition, the sampling period and processing requirements make it inappropriate for emergency condition monitoring. This paper briefly reviews the development of prototype DSP and accelerometer hardware. More importantly, it reviews our work to design prototype vibration alarm filters. Two-axis accelerometer test data from the experimental FloWind vertical axis wind turbine is analyzed and used as a development guide. Two levels of signal processing are considered. The first uses narrow band pre-processing filters at key fundamental frequencies such as the 1P, 2P and 3P. The total vibration energy in each frequency band is calculated and evaluated as a possible alarm trigger. In the second level of signal processing, the total vibration energy in each frequency band is further decomposed using the two-axis directional information. Directional statistics are calculated to differentiate between linear translations and circular translations. After analyzing the acceleration statistics for normal and unusual operating conditions, the acceleration processing system described could be used in automatic early detection of fault conditions. 9 figs.

Calculation of vibrational frequencies through a variational reduced-coupling approach.

Science.gov (United States)

Scribano, Yohann; Benoit, David M

2007-10-28

In this study, we present a new method to perform accurate and efficient vibrational configuration interaction computations for large molecular systems. We use the vibrational self-consistent field (VSCF) method to compute an initial description of the vibrational wave function of the system, combined with the single-to-all approach to compute a sparse potential energy surface at the chosen ab initio level of theory. A Davidson scheme is then used to diagonalize the Hamiltonian matrix built on the VSCF virtual basis. Our method is applied to the computation of the OH-stretch frequency of formic acid and benzoic acid to demonstrate the efficiency and accuracy of this new technique.

Portable vibration exciter

Science.gov (United States)

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

1970-01-01

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

Examining the impact of harmonic correlation on vibrational frequencies calculated in localized coordinates

Energy Technology Data Exchange (ETDEWEB)

Hanson-Heine, Magnus W. D., E-mail: magnus.hansonheine@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

2015-10-28

Carefully choosing a set of optimized coordinates for performing vibrational frequency calculations can significantly reduce the anharmonic correlation energy from the self-consistent field treatment of molecular vibrations. However, moving away from normal coordinates also introduces an additional source of correlation energy arising from mode-coupling at the harmonic level. The impact of this new component of the vibrational energy is examined for a range of molecules, and a method is proposed for correcting the resulting self-consistent field frequencies by adding the full coupling energy from connected pairs of harmonic and pseudoharmonic modes, termed vibrational self-consistent field (harmonic correlation). This approach is found to lift the vibrational degeneracies arising from coordinate optimization and provides better agreement with experimental and benchmark frequencies than uncorrected vibrational self-consistent field theory without relying on traditional correlated methods.

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.

Resonance tunneling electron-vibrational spectroscopy of polyoxometalates.

Science.gov (United States)

Dalidchik, F I; Kovalevskii, S A; Balashov, E M

2017-05-21

The tunneling spectra of the ordered monolayer films of decamolybdodicobaltate (DMDC) compounds deposited from aqueous solutions on HOPG were measured by scanning tunnel microscopy in air. The DMDC spectra, as well as the tunneling spectra of other polyoxometalates (POMs), exhibit well-defined negative differential resistances (NDRs). The mechanism of formation of these spectral features was established from the collection of revealed NDR dependences on the external varying parameters and found to be common to all systems exhibiting Wannier-Stark localization. A model of biresonance tunneling was developed to provide an explanation for the totality of experimental data, both the literature and original, on the tunneling POM probing. A variant of the tunneling electron-vibrational POM spectroscopy was proposed allowing the determination of the three basic energy parameters-energy gaps between the occupied and unoccupied states, frequencies of the vibrational transitions accompanying biresonance electron-tunneling processes, and electron-vibrational interaction constants on the monomolecular level.

Control aid for xenon vibration in reactor

International Nuclear Information System (INIS)

Kanekawa, Takashi.

1990-01-01

In the present invention, the control operation for suppressing xenon vibrations in a reactor is aided for saving forecasting analysis and operator's skills. That is, parameters to be controlled for the suppression of xenon vibrations are power distribution, iodine distribution and xenon distribution. But what can be observed by operaters by the conventional fast overtone method is only the output distribution. In the present invention, the output level of the reactor core is always observed. Then, mathematical processings are conducted for the iodine distribution, the xenon distribution and the power distribution in the reactor core based on the histeresis of the parameters obtained by the measurement using physical constants and reactor design data. The xenon vibration control is aided by displaying the change with time of the distortion in axial direction. Accordingly, operators can always recognize the axial distortion of the power distribution, the iodine distribution and the xenon distribution. (I.S.)

Gearbox Tooth Cut Fault Diagnostics Using Acoustic Emission and Vibration Sensors — A Comparative Study

Directory of Open Access Journals (Sweden)

Yongzhi Qu

2014-01-01

Full Text Available In recent years, acoustic emission (AE sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance.

Gearbox Tooth Cut Fault Diagnostics Using Acoustic Emission and Vibration Sensors — A Comparative Study

Science.gov (United States)

Qu, Yongzhi; He, David; Yoon, Jae; Van Hecke, Brandon; Bechhoefer, Eric; Zhu, Junda

2014-01-01

In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance. PMID:24424467

Trends in Upper-Level Cloud Cover and Surface Divergence Over the Tropical Indo-Pacific Ocean Between 1952 And 1997

Science.gov (United States)

Norris, Joel R.

2005-01-01

This study investigated the spatial pattern of linear trends in surface-observed upper-level (combined mid-level and High-level) cloud cover, precipitation, and surface divergence over the tropical Indo-Pacific Ocean during 1952-1957. Cloud values were obtained from the Extended Edited Cloud Report Archive (EECRA), precipitation values were obtained from the Hulme/Climate Research Unit Data Set, and surface divergence was alternatively calculated from wind reported Comprehensive Ocean-Atmosphere Data Set and from Smith and Reynolds Extended Reconstructed sea level pressure data.

Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical

Energy Technology Data Exchange (ETDEWEB)

Adam, Ahmad Y.; Jensen, Per, E-mail: jensen@uni-wuppertal.de [Fakultät Mathematik und Naturwissenschaften, Physikalische und Theoretische Chemie, Bergische Universität Wuppertal, D-42097 Wuppertal (Germany); Yachmenev, Andrey; Yurchenko, Sergei N. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

2015-12-28

We present the first variational calculation of the isotropic hyperfine coupling constant of the carbon-13 atom in the CH{sub 3} radical for temperatures T = 0, 96, and 300 K. It is based on a newly calculated high level ab initio potential energy surface and hyperfine coupling constant surface of CH{sub 3} in the ground electronic state. The ro-vibrational energy levels, expectation values for the coupling constant, and its temperature dependence were calculated variationally by using the methods implemented in the computer program TROVE. Vibrational energies and vibrational and temperature effects for coupling constant are found to be in very good agreement with the available experimental data. We found, in agreement with previous studies, that the vibrational effects constitute about 44% of the constant’s equilibrium value, originating mainly from the large amplitude out-of-plane bending motion and that the temperature effects play a minor role.

Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical

Science.gov (United States)

Adam, Ahmad Y.; Yachmenev, Andrey; Yurchenko, Sergei N.; Jensen, Per

2015-12-01

We present the first variational calculation of the isotropic hyperfine coupling constant of the carbon-13 atom in the CH3 radical for temperatures T = 0, 96, and 300 K. It is based on a newly calculated high level ab initio potential energy surface and hyperfine coupling constant surface of CH3 in the ground electronic state. The ro-vibrational energy levels, expectation values for the coupling constant, and its temperature dependence were calculated variationally by using the methods implemented in the computer program TROVE. Vibrational energies and vibrational and temperature effects for coupling constant are found to be in very good agreement with the available experimental data. We found, in agreement with previous studies, that the vibrational effects constitute about 44% of the constant's equilibrium value, originating mainly from the large amplitude out-of-plane bending motion and that the temperature effects play a minor role.

Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical

International Nuclear Information System (INIS)

Adam, Ahmad Y.; Jensen, Per; Yachmenev, Andrey; Yurchenko, Sergei N.

2015-01-01

We present the first variational calculation of the isotropic hyperfine coupling constant of the carbon-13 atom in the CH 3 radical for temperatures T = 0, 96, and 300 K. It is based on a newly calculated high level ab initio potential energy surface and hyperfine coupling constant surface of CH 3 in the ground electronic state. The ro-vibrational energy levels, expectation values for the coupling constant, and its temperature dependence were calculated variationally by using the methods implemented in the computer program TROVE. Vibrational energies and vibrational and temperature effects for coupling constant are found to be in very good agreement with the available experimental data. We found, in agreement with previous studies, that the vibrational effects constitute about 44% of the constant’s equilibrium value, originating mainly from the large amplitude out-of-plane bending motion and that the temperature effects play a minor role

Vibration-reducing gloves: transmissibility at the palm of the hand in three orthogonal directions.

Science.gov (United States)

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

2013-01-01

Vibration-reducing (VR) gloves are commonly used as a means to help control exposures to hand-transmitted vibrations generated by powered hand tools. The objective of this study was to characterise the vibration transmissibility spectra and frequency-weighted vibration transmissibility of VR gloves at the palm of the hand in three orthogonal directions. Seven adult males participated in the evaluation of seven glove models using a three-dimensional hand-arm vibration test system. Three levels of hand coupling force were applied in the experiment. This study found that, in general, VR gloves are most effective at reducing vibrations transmitted to the palm along the forearm direction. Gloves that are found to be superior at reducing vibrations in the forearm direction may not be more effective in the other directions when compared with other VR gloves. This casts doubts on the validity of the standardised glove screening test. Practitioner Summary: This study used human subjects to measure three-dimensional vibration transmissibility of vibration-reducing gloves at the palm and identified their vibration attenuation characteristics. This study found the gloves to be most effective at reducing vibrations along the forearm direction. These gloves did not effectively attenuate vibration along the handle axial direction.

Vibration produced by hand-held olive electrical harvesters

Directory of Open Access Journals (Sweden)

Emanuele Cerruto

2012-09-01

Full Text Available The paper reports the results of some laboratory and field tests aimed at assessing the acceleration levels transmitted to the hand-arm system by electric portable harvesters for olive. Four harvesting heads, different for shape and kinematic system, and five bars, different for diameter, length and material (aluminium and carbon fibre, were used in assembling eleven harvesters. The vibrations were measured in two points, next to the handgrips. The laboratory tests allowed the evaluation of the acceleration levels in standard controlled conditions, while the field tests allowed the assessing of the effects of the tree canopy with respect to the no load running. The laboratory tests showed that in reducing the vibration level plays a major role the kinematic system of the harvesting head and then the bar material. The classical flap-type harvester produced accelerations of around 20 m/s2, while by using a harvesting head with two parts in opposite movement, the accelerations were lowered to about 6 m/s2. The use of carbon fibres for the bars, besides the reduction in weight, produced also a reduction in acceleration (from 21 to 16 m/s2. The field tests proved that the tree canopy had a negative effect on the vibrations transmitted to the hand-arm system, especially when the aluminium bar of small diameter was used.

Accurate ab initio vibrational energies of methyl chloride

International Nuclear Information System (INIS)

Owens, Alec; Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

2015-01-01

Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH 3 35 Cl and CH 3 37 Cl. The respective PESs, CBS-35  HL , and CBS-37  HL , are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY 3 Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35  HL and CBS-37  HL PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm −1 , respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH 3 Cl without empirical refinement of the respective PESs

High-Temperature Vibration Damper

Science.gov (United States)

Clarke, Alan; Litwin, Joel; Krauss, Harold

1987-01-01

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

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.

Mechanical vibration and shock analysis, sinusoidal vibration

CERN Document Server

Lalanne, Christian

2014-01-01

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

Vibration mitigation for in-wheel switched reluctance motor driven electric vehicle with dynamic vibration absorbing structures

Science.gov (United States)

Qin, Yechen; He, Chenchen; Shao, Xinxin; Du, Haiping; Xiang, Changle; Dong, Mingming

2018-04-01

This paper presents a new approach for vibration mitigation based on a dynamic vibration absorbing structure (DVAS) for electric vehicles (EVs) that use in-wheel switched reluctance motors (SRMs). The proposed approach aims to alleviate the negative effects of vibration caused by the unbalanced electromagnetic force (UMEF) that arises from road excitations. The analytical model of SRMs is first formulated using Fourier series, and then a model of the coupled longitudinal-vertical dynamics is developed taking into consideration the external excitations consisting of the aerodynamic drag force and road unevenness. In addition, numerical simulations for a conventional SRM-suspension system and two novel DVASs are carried out for varying road levels specified by ISO standards and vehicle velocities. The results of the comparison reveal that a 35% improvement in ride comfort, 30% improvement of road handling, and 68% improvement in air gap between rotor and stator can be achieved by adopting the novel DVAS compared to the conventional SRM-suspension system. Finally, multi-body simulation (MBS) is performed using LMS Motion to validate the feasibility of the proposed DVAS. Analysis of the results shows that the proposed method can augment the effective application of SRMs in EVs.

Vibration test on KMRR reactor structure and primary cooling system piping

Energy Technology Data Exchange (ETDEWEB)

Chung, Seung Hoh; Kim, Tae Ryong; Park, Jin Hoh; Park, Jin Suk; Ryoo, Jung Soo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1994-10-01

Most equipments, piping systems and reactor structures in nuclear power plants are subjected to flow induced vibration due to high temperature and high pressure coolant flowing inside or outside of the equipments, systems and structures. Because the flow induced vibration sometimes causes significant damage to reactor structures and piping systems, it is important and necessary to evaluate the vibration effect on them and to prove their structural integrity. Korea Multipurpose Research Reactor (KMRR) being constructed by KAERI is 30 MWt pool type research reactor. Since its main structures and piping systems were designed and manufactured in accordance with the standards and guidelines for commercial nuclear power plant, it was decided to evaluate their vibratory response in accordance with the standards and guidelines for commercial NPP. The objective of this vibration test is the assessment of vibration levels of KMRR reactor structure and primary cooling piping system for their structural integrity under the steady-state or transient operating condition. 38 figs, 14 tabs, 2 refs. (Author).

Vibration test on KMRR reactor structure and primary cooling system piping

International Nuclear Information System (INIS)

Chung, Seung Hoh; Kim, Tae Ryong; Park, Jin Hoh; Park, Jin Suk; Ryoo, Jung Soo

1994-10-01

Most equipments, piping systems and reactor structures in nuclear power plants are subjected to flow induced vibration due to high temperature and high pressure coolant flowing inside or outside of the equipments, systems and structures. Because the flow induced vibration sometimes causes significant damage to reactor structures and piping systems, it is important and necessary to evaluate the vibration effect on them and to prove their structural integrity. Korea Multipurpose Research Reactor (KMRR) being constructed by KAERI is 30 MWt pool type research reactor. Since its main structures and piping systems were designed and manufactured in accordance with the standards and guidelines for commercial nuclear power plant, it was decided to evaluate their vibratory response in accordance with the standards and guidelines for commercial NPP. The objective of this vibration test is the assessment of vibration levels of KMRR reactor structure and primary cooling piping system for their structural integrity under the steady-state or transient operating condition. 38 figs, 14 tabs, 2 refs. (Author)

IUPAC critical evaluation of the rotational-vibrational spectra of water vapor. Part I-Energy levels and transition wavenumbers for H217O and H218O

International Nuclear Information System (INIS)

Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Carleer, Michel R.; Csaszar, Attila G.; Gamache, Robert R.; Hodges, Joseph T.; Jenouvrier, Alain; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Toth, Robert A.; Vandaele, Ann Carine; Zobov, Nikolai F.; Daumont, Ludovic; Fazliev, Alexander Z.; Furtenbacher, Tibor; Gordon, Iouli E.; Mikhailenko, Semen N.

2009-01-01

This is the first part of a series of articles reporting critically evaluated rotational-vibrational line positions, transition intensities, pressure dependence and energy levels, with associated critically reviewed assignments and uncertainties, for all the main isotopologues of water. The present article contains energy levels and data for line positions of the singly substituted isotopologues H 2 17 O and H 2 18 O. The procedure and code MARVEL, standing for measured active rotational-vibrational energy levels, is used extensively in all stages of determining the validated levels and lines and their self-consistent uncertainties. The spectral regions covered for both isotopologues H 2 17 O and H 2 18 O are 0-17125cm -1 . The energy levels are checked against ones determined from accurate variational calculations. The number of critically evaluated and recommended levels and lines are, respectively, 2687 and 8614 for H 2 17 O, and 4839 and 29 364 for H 2 18 O. The extensive lists of MARVEL lines and levels obtained are deposited in the Supplementary Material, as well as in a distributed information system applied to water, W-DIS, where they can easily be retrieved. A distinguishing feature of the present evaluation of water spectroscopic data is the systematic use of all available experimental data and validation by first-principles theoretical calculations.

Oncoplastic Surgery for Upper/Upper Inner Quadrant Breast Cancer.

Directory of Open Access Journals (Sweden)

Joseph Lin

Full Text Available Tumors located in the upper/upper inner quadrant of the breast warrant more attention. A small lesion relative to the size of breast in this location may be resolved by performing a level I oncoplastic technique. However, a wide excision may significantly reduce the overall quality of the breast shape by distorting the visible breast line. From June 2012 to April 2015, 36 patients with breast cancer located in the upper/upper inner quadrant underwent breast-conservation surgery with matrix rotation mammoplasty. According to the size and location of the tumor relative to the nipple-areola complex, 11 patients underwent matrix rotation with periareolar de-epithelialization (donut group and the other 25 underwent matrix rotation only (non-donut group. The cosmetic results were self-assessed by questionnaires. The average weights of the excised breast lumps in the donut and non-donut groups were 104.1 and 84.5 g, respectively. During the 3-year follow-up period, local recurrence was observed in one case and was managed with nipple-sparing mastectomy followed by breast reconstruction with prosthetic implants. In total, 31 patients (88.6% ranked their postoperative result as either acceptable or satisfactory. The treated breasts were also self-evaluated by 27 patients (77.1% to be nearly identical to or just slightly different from the untreated side. Matrix rotation is an easy breast-preserving technique for treating breast cancer located in the upper/upper inner quadrant of the breast that requires a relatively wide excision. With this technique, a larger breast tumor could be removed without compromising the breast appearance.

Model Predictive Vibration Control Efficient Constrained MPC Vibration Control for Lightly Damped Mechanical Structures

CERN Document Server

Takács, Gergely

2012-01-01

Real-time model predictive controller (MPC) implementation in active vibration control (AVC) is often rendered difficult by fast sampling speeds and extensive actuator-deformation asymmetry. If the control of lightly damped mechanical structures is assumed, the region of attraction containing the set of allowable initial conditions requires a large prediction horizon, making the already computationally demanding on-line process even more complex. Model Predictive Vibration Control provides insight into the predictive control of lightly damped vibrating structures by exploring computationally efficient algorithms which are capable of low frequency vibration control with guaranteed stability and constraint feasibility. In addition to a theoretical primer on active vibration damping and model predictive control, Model Predictive Vibration Control provides a guide through the necessary steps in understanding the founding ideas of predictive control applied in AVC such as: ·         the implementation of ...

Experimental study of heat transfer enhancement due to the surface vibrations in a flexible double pipe heat exchanger

Science.gov (United States)

Hosseinian, A.; Meghdadi Isfahani, A. H.

2018-04-01

In this study, the heat transfer enhancement due to the surface vibration for a double pipe heat exchanger, made of PVDF, is investigated. In order to create forced vibrations (3-9 m/s2, 100 Hz) on the outer surface of the heat exchanger electro-dynamic vibrators are used. Experiments were performed at inner Reynolds numbers ranging from 2533 to 9960. The effects of volume flow rate and temperature on heat transfer performance are evaluated. Results demonstrated that heat transfer coefficient increases by increasing vibration level and mass flow rate. The most increase in heat transfer coefficient is 97% which is obtained for the highest vibration level (9 m/s2) in the experiment range.

The influence of flywheel micro vibration on space camera and vibration suppression

Science.gov (United States)

Li, Lin; Tan, Luyang; Kong, Lin; Wang, Dong; Yang, Hongbo

2018-02-01

Studied the impact of flywheel micro vibration on a high resolution optical satellite that space-borne integrated. By testing the flywheel micro vibration with six-component test bench, the flywheel disturbance data is acquired. The finite element model of the satellite was established and the unit force/torque were applied at the flywheel mounting position to obtain the micro vibration data of the camera. Integrated analysis of the data of the two parts showed that the influence of flywheel micro vibration on the camera is mainly concentrated around 60-80 Hz and 170-230 Hz, the largest angular displacement of the secondary mirror along the optical axis direction is 0.04″ and the maximum angular displacement vertical to optical axis is 0.032″. After the design and installation of vibration isolator, the maximum angular displacement of the secondary mirror is 0.011″, the decay rate of root mean square value of the angular displacement is more than 50% and the maximum is 96.78%. The whole satellite was suspended to simulate the boundary condition on orbit; the imaging experiment results show that the image motion caused by the flywheel micro vibrationis less than 0.1 pixel after installing the vibration isolator.

Determining the Probability of Violating Upper-Level Wind Constraints for the Launch of Minuteman Ill Ballistic Missiles At Vandenberg Air Force Base

Science.gov (United States)

Shafer, Jaclyn A.; Brock, Tyler M.

2013-01-01

The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman Ill ballistic missile. The 30 OSSWF requested the Applied Meteorology Unit (AMU) analyze VAFB sounding data to determine the probability of violating (PoV) upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a graphical user interface (GUI) that will calculate the PoV of each constraint on the day of launch. The AMU suggested also including forecast sounding data from the Rapid Refresh (RAP) model. This would provide further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours, and help to improve the overall upper winds forecast on launch day.

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

Ground Vibration Attenuation Measurement using Triaxial and Single Axis Accelerometers

Science.gov (United States)

Mohammad, A. H.; Yusoff, N. A.; Madun, A.; Tajudin, S. A. A.; Zahari, M. N. H.; Chik, T. N. T.; Rahman, N. A.; Annuar, Y. M. N.

2018-04-01

Peak Particle Velocity is one of the important term to show the level of the vibration amplitude especially traveling wave by distance. Vibration measurement using triaxial accelerometer is needed to obtain accurate value of PPV however limited by the size and the available channel of the data acquisition module for detailed measurement. In this paper, an attempt to estimate accurate PPV has been made by using only a triaxial accelerometer together with multiple single axis accelerometer for the ground vibration measurement. A field test was conducted on soft ground using nine single axis accelerometers and a triaxial accelerometer installed at nine receiver location R1 to R9. Based from the obtained result, the method shows convincing similarity between actual PPV with the calculated PPV with error ratio 0.97. With the design method, vibration measurement equipment size can be reduced with fewer channel required.

Vibrations of rotating machinery

CERN Document Server

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

2017-01-01

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

Vibration features of an 180 kW maglev circulator test rig

International Nuclear Information System (INIS)

Su Jiageng; Li Hongwei; Shi Qian; Sha Honglei; Yu Suyuan

2015-01-01

The helium circulator is the key equipment to drive the helium gas flowing in the primary loop for energy exchange in HTGR. Active magnetic bearings (AMB) have been considered as an alternative to replace traditional mechanical bearings in the helium circulator. Such contactless bearings do not have frictional wear and can be used to suppress vibration in rotor-dynamic applications. It is necessary to study the vibration characteristics of the maglev helium circulator to guarantee the reactor safety. Therefore, a maglev circulator test rig was built. The power of the circulator is 180 kW and the maximum speed is 17000 rpm. For the time being, the test atmosphere is air. In this paper the test rig was introduced. Vibration test work of the maglev circulator was also carried out. The measuring points were arranged at the seat because the seat vibration level is important to evaluate the machine noise. The measuring points were also arranged at the base of the circulator housing to better study the vibration characteristics. The vibrations were measured by the LC-8024 multichannel machinery diagnoses system. At each measuring point the vibrations were detected in three directions (X, Y and Z) with the vibration acceleration sensors. The test speeds varied from 1000 rpm to 17000 rpm with an increase of 1000 rpm each time. The vibration values of the seat are from 89.5 dB at 1000 rpm to 113.3 dB at 17000 rpm. The test results showed that the maglev circulator exhibits good vibration properties. This work will offer important theoretical base and engineering experience to explore the high-speed helium circulator in HTGR. (author)

Serum of 25-Hydroxyvitamin D and Intact Parathyroid Hormone Levels in Postmenopausal Women with Hip and Upper Limb Fractures.

Science.gov (United States)

Lv, Jiang-Tao; Zhang, Ying-Ying; Tian, Shao-Qi; Sun, Kang

2016-05-01

To assess the serum of 25-hydroxyvitamin D (25(OH)D) and intact parathyroid hormone (iPTH) levels in postmenopausal women from northern China with hip and upper limb fractures. Case-control. Affiliated Hospital of Qingdao University. Postmenopausal women diagnosed with hip fracture (n = 335) and matched controls without fracture (n = 335). Between 2011 and 2013, fasting venous samples were analyzed for 25(OH)D, iPTH, alkaline phosphatase (ALP), calcium, and phosphorus. All women completed a standardized questionnaire designed to document putative risk factors for fractures. Eight percent of participants had vitamin D deficiency, and 66.0% had secondary hyperparathyroidism. Serum 25(OH)D levels were significantly (P lower in women with hip fracture than in controls. Multivariate logistic regression analysis adjusted for common risk factors showed that serum 25(OH)D of 20 ng/mL or less was an independent indicator of hip fracture (odds ratio (OR) = 2.98, 95% confidence interval (CI) = 2.11-4.20) and concomitant upper limb fracture in those with existing hip fractures (OR = 4.77, 95% CI = 1.60-10.12). The area under the receiver operating characteristic curve of 25(OH)D was 0.77 (95% CI = 0.68-0.84) for hip fracture and 0.80 (95% CI = 0.72-0.89) for hip and upper limb fractures. Vitamin D insufficiency and secondary hyperparathyroidism were a common problem in postmenopausal women who presented with concomitant hip and upper limb fractures, suggesting that they might contribute to the pathophysiology of fractures in postmenopausal women. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

Hybrid Vibration Control under Broadband Excitation and Variable Temperature Using Viscoelastic Neutralizer and Adaptive Feedforward Approach

Directory of Open Access Journals (Sweden)

João C. O. Marra

2016-01-01

Full Text Available Vibratory phenomena have always surrounded human life. The need for more knowledge and domain of such phenomena increases more and more, especially in the modern society where the human-machine integration becomes closer day after day. In that context, this work deals with the development and practical implementation of a hybrid (passive-active/adaptive vibration control system over a metallic beam excited by a broadband signal and under variable temperature, between 5 and 35°C. Since temperature variations affect directly and considerably the performance of the passive control system, composed of a viscoelastic dynamic vibration neutralizer (also called a viscoelastic dynamic vibration absorber, the associative strategy of using an active-adaptive vibration control system (based on a feedforward approach with the use of the FXLMS algorithm working together with the passive one has shown to be a good option to compensate the neutralizer loss of performance and generally maintain the extended overall level of vibration control. As an additional gain, the association of both vibration control systems (passive and active-adaptive has improved the attenuation of vibration levels. Some key steps matured over years of research on this experimental setup are presented in this paper.

Urban vibrations

DEFF Research Database (Denmark)

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

2012-01-01

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

Correlation of analysis with high level vibration test results for primary coolant piping

International Nuclear Information System (INIS)

Park, Y.J.; Hofmayer, C.H.; Costello, J.F.

1992-01-01

Dynamic tests on a modified 1/2.5-scale model of pressurized water reactor (PWR) primary coolant piping were performed using a large shaking table at Tadotsu, Japan. The High Level Vibration Test (HLVT) program was part of a cooperative study between the United States (Nuclear Regulatory Commission/Brookhaven National Laboratory, NRC/BNL) and Japan (Ministry of International Trade and Industry/Nuclear Power Engineering Center). During the test program, the excitation level of each test run was gradually increased up to the limit of the shaking table and significant plastic strains, as well as cracking, were induced in the piping. To fully utilize the test results, NRC/BNL sponsored a project to develop corresponding analytical predictions for the nonlinear dynamic response of the piping for selected test runs. The analyses were performed using both simplified and detailed approaches. The simplified approaches utilize a linear solution and an approximate formulation for nonlinear dynamic effects such as the use of a deamplification factor. The detailed analyses were performed using available nonlinear finite element computer codes, including the MARC, ABAQUS, ADINA and WECAN codes. A comparison of various analysis techniques with the test results shows a higher prediction error in the detailed strain values in the overall response values. A summary of the correlation analyses was presented before the BNL. This paper presents a detailed description of the various analysis results and additional comparisons with test results

Selective vibration sensing: a new concept for activity-sensing rate-responsive pacing.

Science.gov (United States)

Lau, C P; Stott, J R; Toff, W D; Zetlein, M B; Ward, D E; Camm, A J

1988-09-01

A clinically available model of an activity-sensing, rate-responsive pacemaker (Activitrax, Medtronic) utilizes body vibration during exercise as an indicator of the need for a rate increase. Although having the advantage of rapid onset of rate response, this system lacks specificity and the rate response does not closely correlate with the level of exertion. In addition, this pacemaker is susceptible to the effects of extraneous vibration. In this study involving 20 normal subjects fitted with an external Activitrax pacemaker, the rate responses to a variety of exercises were studied and were compared with the corresponding sinus rates. The vibration generated at the level of the pacemaker was also measured by accelerometers in three axes. Only a fair correlation (r = 0.51) was achieved between the pacemaker rate and the sinus rate. The total root mean square value of acceleration in either the anteroposterior or the vertical axes was found to have a better correlation (r = 0.8). As the main accelerations during physical activities were in the lower frequency range (0.1-4 Hz), a low-pass filter was used to reduce the influence of extraneous vibration. Selective sensing of the acceleration level may be usefully implemented in an algorithm for activity pacing.

Two-phase flow induced vibrations in CANDU steam generators

International Nuclear Information System (INIS)

Gidi, A.

2009-01-01

The U-Bend region of nuclear steam generators tube bundles have suffered from two-phase cross flow induced vibrations. Tubes in this region have experienced high amplitude vibrations leading to catastrophic failures. Turbulent buffeting and fluid-elastic instability has been identified as the main causes. Previous investigations have focused on flow regime and two-phase flow damping ratio. However, tube bundles in steam generators have vapour generated on the surface of the tubes, which might affect the flow regime, void fraction distribution, turbulent intensity levels and tube-flow interaction, all of which have the potential to change the tube vibration response. A cantilevered tube bundle made of electric cartridges heaters was built and tested in a Freon-11 flow loop at McMaster University. Tubes were arranged in a parallel triangular configuration. The bundle was exposed to two-phase cross flows consisting of different combinations of void from two sources, void generated upstream of the bundle and void generated at the surface of the tubes. Tube tip vibration response was measured optically and void fraction was measured by gamma densitometry technique. It was found that tube vibration amplitude in the transverse direction was reduced by a factor of eight for void fraction generated at the tube surfaces only, when compared to the upstream only void generation case. The main explanation for this effect is a reduction in the correlation length of the turbulent buffeting forcing function. Theoretical calculations of the tube vibration response due to turbulent buffeting under the same experimental conditions predicted a similar reduction in tube amplitude. The void fraction for the fluid-elastic instability threshold in the presence of tube bundle void fraction generation was higher than that for the upstream void fraction generation case. The first explanation of this difference is the level of turbulent buffeting forces the tube bundle was exposed to

Coherent vibrational dynamics

CERN Document Server

Lanzani, Guglielmo; De Silvestri, Sandro

2007-01-01

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

Nonlinear convergence active vibration absorber for single and multiple frequency vibration control

Science.gov (United States)

Wang, Xi; Yang, Bintang; Guo, Shufeng; Zhao, Wenqiang

2017-12-01

This paper presents a nonlinear convergence algorithm for active dynamic undamped vibration absorber (ADUVA). The damping of absorber is ignored in this algorithm to strengthen the vibration suppressing effect and simplify the algorithm at the same time. The simulation and experimental results indicate that this nonlinear convergence ADUVA can help significantly suppress vibration caused by excitation of both single and multiple frequency. The proposed nonlinear algorithm is composed of equivalent dynamic modeling equations and frequency estimator. Both the single and multiple frequency ADUVA are mathematically imitated by the same mechanical structure with a mass body and a voice coil motor (VCM). The nonlinear convergence estimator is applied to simultaneously satisfy the requirements of fast convergence rate and small steady state frequency error, which are incompatible for linear convergence estimator. The convergence of the nonlinear algorithm is mathematically proofed, and its non-divergent characteristic is theoretically guaranteed. The vibration suppressing experiments demonstrate that the nonlinear ADUVA can accelerate the convergence rate of vibration suppressing and achieve more decrement of oscillation attenuation than the linear ADUVA.

Flow induced vibration of secondary piping of LMFBR

International Nuclear Information System (INIS)

Gibert, R.J.; Axisa, F.

1977-01-01

This paper presents a method for evaluating the characteristics of vibrations caused by internal flow in three-dimensional piping systems conveying high density fluids. The excitation of the circuit is mainly caused by the flow singularities, and it is shown that the problem may be reduced to calculate the response of the circuit to an acoustical pressure discontinuity, localised at each flow singularity. The paper is divided into two main parts: First part is devoted to the theoretical formulation of the coupled acoustical-mechanical problem and to its numerical solution by the french computer code TEDEL. Second part describes an experimental test of the method. The tested piping system consists of a stainless steel tube circuit comprising four 909 bends, conveying water. Vibrations are excited by a half closed gate valve. Satisfactory results are obtained concerning both the frequencies of resonance of the circuit and the level of the vibrations observed

Vibration transducer calibration techniques

Science.gov (United States)

Brinkley, D. J.

1980-09-01

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

Parameter definition using vibration prediction software leads to significant drilling performance improvements

Energy Technology Data Exchange (ETDEWEB)

Amorim, Dalmo; Hanley, Chris Hanley; Fonseca, Isaac; Santos, Juliana [National Oilwell Varco, Houston TX (United States); Leite, Daltro J.; Borella, Augusto; Gozzi, Danilo [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)

2012-07-01

The understanding and mitigation of downhole vibration has been a heavily researched subject in the oil industry as it results in more expensive drilling operations, as vibrations significantly diminish the amount of effective drilling energy available to the bit and generate forces that can push the bit or the Bottom Hole Assembly (BHA) off its concentric axis of rotation, producing high magnitude impacts with the borehole wall. In order to drill ahead, a sufficient amount of energy must be supplied by the rig to overcome the resistance of the drilling system, including the reactive torque of the system, drag forces, fluid pressure losses and energy dissipated by downhole vibrations, then providing the bit with the energy required to fail the rock. If the drill string enters resonant modes of vibration, not only does it decreases the amount of available energy to drill, but increases the potential for catastrophic downhole equipment and drilling bit failures. In this sense, the mitigation of downhole vibrations will result in faster, smoother, and cheaper drilling operations. A software tool using Finite Element Analysis (FEA) has been developed to provide better understanding of downhole vibration phenomena in drilling environments. The software tool calculates the response of the drilling system at various input conditions, based on the design of the wellbore along with the geometry of the Bottom Hole Assembly (BHA) and the drill string. It identifies where undesired levels of resonant vibration will be driven by certain combinations of specific drilling parameters, and also which combinations of drilling parameters will result in lower levels of vibration, so the least shocks, the highest penetration rate and the lowest cost per foot can be achieved. With the growing performance of personal computers, complex software systems modeling the drilling vibrations using FEA has been accessible to a wider audience of field users, further complimenting with real time

A vibration sieve

Energy Technology Data Exchange (ETDEWEB)

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

1982-01-01

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

Influence of Chair Vibrations on Indoor Sonic Boom Annoyance

Science.gov (United States)

Rathsam, Jonathan; Klos, Jacob; Loubeau, Alexandra

2015-01-01

One goal of NASA’s Commercial Supersonic Technology Project is to identify candidate noise metrics suitable for regulating quiet sonic boom aircraft. A suitable metric must consider the short duration and pronounced low frequency content of sonic booms. For indoor listeners, rattle and creaking sounds and floor and chair vibrations may also be important. The current study examined the effect of such vibrations on the annoyance of test subjects seated indoors. The study involved two chairs exposed to nearly identical acoustic levels: one placed directly on the floor, and the other isolated from floor vibrations by pneumatic elastomeric mounts. All subjects experienced both chairs, sitting in one chair for the first half of the experiment and the other chair for the remaining half. Each half of the experiment consisted of 80 impulsive noises played at the exterior of the sonic boom simulator. When all annoyance ratings were analyzed together there appeared to be no difference in mean annoyance with isolation condition. When the apparent effect of transfer bias was removed, a subtle but measurable effect of vibration on annoyance was identified.

Vibrationally averaged dipole moments of methane and benzene isotopologues

Energy Technology Data Exchange (ETDEWEB)

Arapiraca, A. F. C. [Laboratório de Átomos e Moléculas Especiais, Departamento de Física, ICEx, Universidade Federal de Minas Gerais, P. O. Box 702, 30123-970 Belo Horizonte, MG (Brazil); Centro Federal de Educação Tecnológica de Minas Gerais, Coordenação de Ciências, CEFET-MG, Campus I, 30.421-169 Belo Horizonte, MG (Brazil); Mohallem, J. R., E-mail: rachid@fisica.ufmg.br [Laboratório de Átomos e Moléculas Especiais, Departamento de Física, ICEx, Universidade Federal de Minas Gerais, P. O. Box 702, 30123-970 Belo Horizonte, MG (Brazil)

2016-04-14

DFT-B3LYP post-Born-Oppenheimer (finite-nuclear-mass-correction (FNMC)) calculations of vibrationally averaged isotopic dipole moments of methane and benzene, which compare well with experimental values, are reported. For methane, in addition to the principal vibrational contribution to the molecular asymmetry, FNMC accounts for the surprisingly large Born-Oppenheimer error of about 34% to the dipole moments. This unexpected result is explained in terms of concurrent electronic and vibrational contributions. The calculated dipole moment of C{sub 6}H{sub 3}D{sub 3} is about twice as large as the measured dipole moment of C{sub 6}H{sub 5}D. Computational progress is advanced concerning applications to larger systems and the choice of appropriate basis sets. The simpler procedure of performing vibrational averaging on the Born-Oppenheimer level and then adding the FNMC contribution evaluated at the equilibrium distance is shown to be appropriate. Also, the basis set choice is made by heuristic analysis of the physical behavior of the systems, instead of by comparison with experiments.

VIBRATION ISOLATION SYSTEM PROBABILITY ANALYSIS

Directory of Open Access Journals (Sweden)

Smirnov Vladimir Alexandrovich

2012-10-01

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

Vibration Theory, Vol. 3

DEFF Research Database (Denmark)

Nielsen, Søren R. K.

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

Geometric Filtering Effect of Vertical Vibrations in Railway Vehicles

Directory of Open Access Journals (Sweden)

Mădălina Dumitriu

2012-09-01

Full Text Available The paper herein examines the geometric filtering effect coming from the axle base of a railway vehicle upon the vertical vibrations behavior, due to the random irregularities of the track. For this purpose, the complete model of a two-level suspension and flexible carbody vehicle has been taken into account. Following the modal analysis, the movement equations have been treated in an original manner and brought to a structure that points out at the symmetrical and anti-symmetrical decoupled movements of vehicle and their excitation modes. There has been shown that the geometric filtering has a selective behavior in decreasing the level of vibrations, and its contribution is affected by the axle base magnitude, rolling speed and frequency range.

Resonances in photoionization. Cross section for vibrationally excited H2

International Nuclear Information System (INIS)

Mezei, J.Zs.; Jungen, Ch.

2011-01-01

Complete text of publication follows. Diatomic molecular Hydrogen is the most abundant molecule in interstellar molecular clouds. The modeling of these environments relies on accurate cross sections for the various relevant processes. Among them, the photoionization plays a major role in the kinetics and in the energy exchanges involving H 2 . The recent discovery of vibrationally excited molecular hydrogen in extragalactic environments revealed the need for accurate evaluation of the corresponding photoionization cross sections. In the present work we report theoretical photoionization cross sections for excitation from excited vibrational levels of the ground state, dealing with the Q(N = 1) (ΔN = 0, where N is the total angular momentum of the molecule) transitions which account for roughly one third of the total photoabsorption cross section. We will focus on the v' = 1 excited level of the ground electronic state. Our calculations are based on Multichannel Quantum Defect Theory (MQDT), which allows us to take into account of the full manifold of Rydberg states and their interactions with the electronic continuum. We have carried out two types of MQDT calculations. First, we omitted all open channels and calculated energy levels, wave functions and spontaneous emission Einstein coefficients, making use of the theoretical method presented in [2]. In a second set of calculations we included the open ionization channels in the computations getting the continuum phase shifts, channel mixing coefficients and channel dipole moments and finally the photoabsorption/ photoionization cross section. The cross section is dominated by the presence of resonance structures corresponding to excitation of various vibrational levels of bound electronic states which lie above the ionization threshold. In order to assess the importance of the resonances we have calculated for each vibrational interval (the energy interval between two consecutive ionization thresholds) the

Hot Ground Vibration Tests

Data.gov (United States)

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

Low Cost Digital Vibration Meter.

Science.gov (United States)

Payne, W Vance; Geist, Jon

2007-01-01

This report describes the development of a low cost, digital Micro Electro Mechanical System (MEMS) vibration meter that reports an approximation to the RMS acceleration of the vibration to which the vibration meter is subjected. The major mechanical element of this vibration meter is a cantilever beam, which is on the order of 500 µm in length, with a piezoresistor deposited at its base. Vibration of the device in the plane perpendicular to the cantilever beam causes it to bend, which produces a measurable change in the resistance of a piezoresistor. These changes in resistance along with a unique signal-processing scheme are used to determine an approximation to the RMS acceleration sensed by the device.

Comparison of anthropometry, upper-body strength, and lower-body power characteristics in different levels of Australian football players.

Science.gov (United States)

Bilsborough, Johann C; Greenway, Kate G; Opar, David A; Livingstone, Steuart G; Cordy, Justin T; Bird, Stephen R; Coutts, Aaron J

2015-03-01

The aim of this study was to compare the anthropometry, upper-body strength, and lower-body power characteristics in elite junior, sub-elite senior, and elite senior Australian Football (AF) players. Nineteen experienced elite senior (≥4 years Australian Football League [AFL] experience), 27 inexperienced elite senior (free soft tissue mass [FFSTM], fat mass, and bone mineral content) with dual-energy x-ray absorptiometry, upper-body strength (bench press and bench pull), and lower-body power (countermovement jump [CMJ] and squat jump with 20 kg). A 1-way analysis of variance assessed differences between the playing levels in these measures, whereas relationships between anthropometry and performance were assessed with Pearson's correlation. The elite senior and sub-elite senior players were older and heavier than the elite junior players (p ≤ 0.05). Both elite playing groups had greater total FFSTM than both the sub-elite and junior elite players; however, there were only appendicular FFSTM differences between the junior elite and elite senior players (p squat performance measures (r = 0.33-0.55). Australian Football players' FFSTM are different between playing levels, which are likely because of training and partly explain the observed differences in performance between playing levels highlighting the importance of optimizing FFSTM in young players.

Hearing with an atympanic ear: good vibration and poor sound-pressure detection in the royal python, Python regius.

Science.gov (United States)

Christensen, Christian Bech; Christensen-Dalsgaard, Jakob; Brandt, Christian; Madsen, Peter Teglberg

2012-01-15

Snakes lack both an outer ear and a tympanic middle ear, which in most tetrapods provide impedance matching between the air and inner ear fluids and hence improve pressure hearing in air. Snakes would therefore be expected to have very poor pressure hearing and generally be insensitive to airborne sound, whereas the connection of the middle ear bone to the jaw bones in snakes should confer acute sensitivity to substrate vibrations. Some studies have nevertheless claimed that snakes are quite sensitive to both vibration and sound pressure. Here we test the two hypotheses that: (1) snakes are sensitive to sound pressure and (2) snakes are sensitive to vibrations, but cannot hear the sound pressure per se. Vibration and sound-pressure sensitivities were quantified by measuring brainstem evoked potentials in 11 royal pythons, Python regius. Vibrograms and audiograms showed greatest sensitivity at low frequencies of 80-160 Hz, with sensitivities of -54 dB re. 1 m s(-2) and 78 dB re. 20 μPa, respectively. To investigate whether pythons detect sound pressure or sound-induced head vibrations, we measured the sound-induced head vibrations in three dimensions when snakes were exposed to sound pressure at threshold levels. In general, head vibrations induced by threshold-level sound pressure were equal to or greater than those induced by threshold-level vibrations, and therefore sound-pressure sensitivity can be explained by sound-induced head vibration. From this we conclude that pythons, and possibly all snakes, lost effective pressure hearing with the complete reduction of a functional outer and middle ear, but have an acute vibration sensitivity that may be used for communication and detection of predators and prey.

Accurate ab initio vibrational energies of methyl chloride

Energy Technology Data Exchange (ETDEWEB)

Owens, Alec, E-mail: owens@mpi-muelheim.mpg.de [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany); Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT London (United Kingdom); Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan [Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT London (United Kingdom); Thiel, Walter [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)

2015-06-28

Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH{sub 3}{sup 35}Cl and CH{sub 3}{sup 37}Cl. The respective PESs, CBS-35{sup  HL}, and CBS-37{sup  HL}, are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY {sub 3}Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35{sup  HL} and CBS-37{sup  HL} PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm{sup −1}, respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH{sub 3}Cl without empirical refinement of the respective PESs.

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

Assessment of Mismatch at Indicated Level of the Upper Side Zone of LZC on abnormal operations

International Nuclear Information System (INIS)

Kim, Sung-Min; Park, Joong-Woo; Kho, Dae-Hack; Seo, Hyung-Beom; Han, Bong-Gyun; Moon, Jin-Soo

2006-01-01

Liquid Zone Control System of CANDU reactor provides bulk and spatial control. This system has produced abnormal operations with water level increase due to refueling since 1998. The abnormal operations of LZC system at Wolsong 2 can be divided into two periods. One is the sudden drop with continuous operation mode of LZC compressor and the other one is cycling with the on-off operation mode of the LZC compressor. It is identified through the communication with other CANDU reactors that this phenomenon is not unique to Wolsong. Whenever the upper side zone (1,8,6,13) level exceeded 80%, these abnormal operations occurred and mismatch between indicated and actual zone level was found. Counter-plan is prepared to ease these abnormal operations by physicist own efforts at Wolsong 2

Prediction of high level vibration test results by use of available inelastic analysis techniques

International Nuclear Information System (INIS)

Hofmayer, C.H.; Park, Y.J.; Costello, J.F.

1991-01-01

As part of a cooperative study between the United States and Japan, the US Nuclear Regulatory Commission and the Ministry of International Trade and Industry of Japan agreed to perform a test program that would subject a large scale piping model to significant plastic strains under excitation conditions much greater than the design condition for nuclear power plants. The objective was to compare the results of the tests with state-of-the-art analyses. Comparisons were done at different excitation levels from elastic to elastic-plastic to levels where cracking was induced in the test model. The program was called the high Level Vibration Test (HLVT). The HLVT was performed on the seismic table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Test Center in Japan. The test model was constructed by modifying the 1/2.5 scale model of one loop of a PWR primary coolant system which was previously tested by NUPEC as part of their seismic proving test program. A comparison of various analysis techniques with test results shows a higher prediction error in the detailed strain values than in the overall response values. This prediction error is magnified as the plasticity in the test model increases. There is no significant difference in the peak responses between the simplified and the detailed analyses. A comparison between various detailed finite element model runs indicates that the material properties and plasticity modeling have a significant impact on the plastic strain responses under dynamic loading reversals. 5 refs., 12 figs

On the neutron noise diagnostics of pressurized water reactor control rod vibrations II. Stochastic vibrations

International Nuclear Information System (INIS)

Pazsit, I.; Glockler, O.

1984-01-01

In an earlier publication, using the theory of neutron fluctuations induced by a vibrating control rod, a complete formal solution of rod vibration diagnostics based on neutron noise measurements was given in terms of Fourier-transformed neutron detector time signals. The suggested procedure was checked in numerical simulation tests where only periodic vibrations could be considered. The procedure and its numerical testing are elaborated for stochastic two-dimensional vibrations. A simple stochastic theory of two-dimensional flow-induced vibrations is given; then the diagnostic method is formulated in the stochastic case, that is, in terms of neutron detector auto- and crosspower spectra. A previously suggested approximate rod localization technique is also formulated in the stochastic case. Applicability of the methods is then investigated in numerical simulation tests, using the proposed model of stochastic two-dimensional vibrations when generating neutron detector spectra that simulate measured data

O2(a1Δ) vibrational kinetics in oxygen-iodine laser

Science.gov (United States)

Torbin, A. P.; Pershin, A. A.; Heaven, M. C.; Azyazov, V. N.; Mebel, A. M.

2018-04-01

Kinetics of vibrationally-excited singlet oxygen O2(a1Δ,ν) in gas mixture O3/N2/CO2 was studied using a pulse laser technique. Molecules O2(a1Δ,ν) were produced by laser photolysis of ozone at 266 nm. The O3 molecules number density was followed using time-resolved absorption spectroscopy. It was found that an upper bound for the rate constant of chemical reaction O2(a1Δ,ν)+ O3 is about 10-15 cm3/s. The rate constants of O2(a1Δ,ν= 1, 2 and 3) quenching by CO2 are presented.

General principles of vibrational spectroscopies

NARCIS (Netherlands)

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

2000-01-01

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

INFLUENCE OF SNOWFALL ON BLOOD LEAD LEVELS OF FREE-FLYING BALD EAGLES (HALIAEETUS LEUCOCEPHALUS) IN THE UPPER MISSISSIPPI RIVER VALLEY.

Science.gov (United States)

Lindblom, Ronald A; Reichart, Letitia M; Mandernack, Brett A; Solensky, Matthew; Schoenebeck, Casey W; Redig, Patrick T

2017-10-01

Lead poisoning of scavenging raptors occurs primarily via consumption of game animal carcasses containing lead, which peaks during fall firearm hunting seasons. We hypothesized that snowfall would mitigate exposure by concealing carcasses. We categorized blood lead level (BLL) for a subsample of Bald Eagles (Haliaeetus leucocephalus) from the Upper Mississippi River Valley and described BLL with respect to age, sex, and snowfall. We captured Bald Eagles overwintering in the Upper Mississippi River Valley (n=55) between December 1999 and January 2002. Individual BLL ranged from nondetectable to 335 μg/dL, with 73% of the samples testing positive for acute exposure to lead. Eagle BLL did not significantly differ between age or sex, but levels were higher immediately following the hunting season, and they were lower when the previous month's snowfall was greater than 11 cm. This study suggests a window of time between the white-tailed deer (Odocoileus virginianus) hunting season and the onset of snow when the population experienced peak exposure to lead. Combining these findings with existing research, we offer a narrative of the annual lead exposure cycle of Upper Mississippi River Valley Bald Eagles. These temporal associations are necessary considerations for accurate collection and interpretation of BLL.

Kinetics of highly vibrationally excited O2(X) molecules in inductively-coupled oxygen plasmas

Science.gov (United States)

Annušová, Adriana; Marinov, Daniil; Booth, Jean-Paul; Sirse, Nishant; Lino da Silva, Mário; Lopez, Bruno; Guerra, Vasco

2018-04-01

The high degree of vibrational excitation of O2 ground state molecules recently observed in inductively coupled plasma discharges is investigated experimentally in more detail and interpreted using a detailed self-consistent 0D global kinetic model for oxygen plasmas. Additional experimental results are presented and used to validate the model. The vibrational kinetics considers vibrational levels up to v = 41 and accounts for electron impact excitation and de-excitation (e-V), vibration-to-translation relaxation (V-T) in collisions with O2 molecules and O atoms, vibration-to-vibration energy exchanges (V-V), excitation of electronically excited states, dissociative electron attachment, and electron impact dissociation. Measurements were performed at pressures of 10–80 mTorr (1.33 and 10.67 Pa) and radio frequency (13.56 MHz) powers up to 500 W. The simulation results are compared with the absolute densities in each O2 vibrational level obtained by high sensitivity absorption spectroscopy measurements of the Schumann–Runge bands for O2(X, v = 4–18), O(3 P) atom density measurements by two-photon absorption laser induced fluorescence (TALIF) calibrated against Xe, and laser photodetachment measurements of the O‑ negative ions. The highly excited O2(X, v) distribution exhibits a shape similar to a Treanor-Gordiets distribution, but its origin lies in electron impact e-V collisions and not in V-V up-pumping, in contrast to what happens in all other molecular gases known to date. The relaxation of vibrational quanta is mainly due to V-T energy-transfer collisions with O atoms and to electron impact dissociation of vibrationally excited molecules, e+O2(X, v)→O(3P)+O(3P).

A Comparative Study of Ground and Underground Vibrations Induced by Bench Blasting

Directory of Open Access Journals (Sweden)

Xiuzhi Shi

2016-01-01

Full Text Available Ground vibrations originating from bench blasting may cause damage to slopes, structures, and underground workings in close proximity to an operating open-pit mine. It is important to monitor and predict ground vibration levels induced by blasting and to take measures to reduce their hazardous effects. The aims of this paper are to determine the weaker protection objects by comparatively studying bench blasting induced vibrations obtained at surface and in an underground tunnel in an open-pit mine and thus to seek vibration control methods to protect engineering objects at the site. Vibrations arising from measurement devices at surface and in an underground tunnel at the Zijinshan Open-Pit Mine were obtained. Comparative analysis of the peak particle velocities shows that, in the greatest majority of cases, surface values are higher than underground values for the same vibration distance. The transmission laws of surface and underground vibrations were established depending on the type of rock mass, the explosive charge, and the distance. Compared with the Chinese Safety Regulations for Blasting (GB6722-2014, the bench blasting induced vibrations would not currently cause damage to the underground tunnel. According to the maximum allowable peak particle velocities for different objects, the permitted maximum charges per delay are obtained to reduce damage to these objects at different distances.

Neurophysiological findings in vibration-exposed male workers.

Science.gov (United States)

Strömberg, T; Dahlin, L B; Rosén, I; Lundborg, G

1999-04-01

Fractionated nerve conduction, vibrotactile sense, and temperature thresholds were studied in 73 symptomatic vibration-exposed male workers. Three symptomatic groups were distinguished: patients with isolated sensorineural symptoms; with isolated vasospastic problems; and with both. Clinical carpal tunnel syndrome occurred in 14 patients and abnormal cold intolerance (without blanching of the fingers) in 23. In the group as a whole, nerve conduction studies were abnormal in the median nerve but not in the ulnar nerve and vibration perception and temperature thresholds were impaired. Of the three symptomatic groups, patients with isolated sensorineural symptoms differed from controls. No differences were seen between patients with and without clinical carpal tunnel syndrome. With severe sensorineural symptoms the vibration perception thresholds, but not the values of the nerve conduction studies, were further impaired. The results indicated two injuries that are easily confused: one at receptor level in the fingertips and one in the carpal tunnel. Careful clinical assessment, neurophysiological testing, and examination of vibrotactile sense are required before carpal tunnel release should be considered in these patients.

System-Level Coupled Modeling of Piezoelectric Vibration Energy Harvesting Systems by Joint Finite Element and Circuit Analysis

Directory of Open Access Journals (Sweden)

Congcong Cheng

2016-01-01

Full Text Available A practical piezoelectric vibration energy harvesting (PVEH system is usually composed of two coupled parts: a harvesting structure and an interface circuit. Thus, it is much necessary to build system-level coupled models for analyzing PVEH systems, so that the whole PVEH system can be optimized to obtain a high overall efficiency. In this paper, two classes of coupled models are proposed by joint finite element and circuit analysis. The first one is to integrate the equivalent circuit model of the harvesting structure with the interface circuit and the second one is to integrate the equivalent electrical impedance of the interface circuit into the finite element model of the harvesting structure. Then equivalent circuit model parameters of the harvesting structure are estimated by finite element analysis and the equivalent electrical impedance of the interface circuit is derived by circuit analysis. In the end, simulations are done to validate and compare the proposed two classes of system-level coupled models. The results demonstrate that harvested powers from the two classes of coupled models approximate to theoretic values. Thus, the proposed coupled models can be used for system-level optimizations in engineering applications.

Random vibrations theory and practice

CERN Document Server

Wirsching, Paul H; Ortiz, Keith

1995-01-01

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

Numerical solutions of anharmonic vibration of BaO and SrO molecules

Energy Technology Data Exchange (ETDEWEB)

Pramudito, Sidikrubadi; Sanjaya, Nugraha Wanda [Theoretical Physics Division, Department of Physics, Bogor Agricultural University, Jalan Meranti Kampus IPB Dramaga Bogor 16680 (Indonesia); Sumaryada, Tony, E-mail: tsumaryada@ipb.ac.id [Theoretical Physics Division, Department of Physics, Bogor Agricultural University, Jalan Meranti Kampus IPB Dramaga Bogor 16680 (Indonesia); Computational Biophysics and Molecular Modeling Research Group (CBMoRG), Department of Physics, Bogor Agricultural University, Jalan Meranti Kampus IPB Dramaga Bogor 16680 (Indonesia)

2016-03-11

The Morse potential is a potential model that is used to describe the anharmonic behavior of molecular vibration between atoms. The BaO and SrO molecules, which are two almost similar diatomic molecules, were investigated in this research. Some of their properties like the value of the dissociation energy, the energy eigenvalues of each energy level, and the profile of the wavefunctions in their correspondence vibrational states were presented in this paper. Calculation of the energy eigenvalues and plotting the wave function’s profiles were performed using Numerov method combined with the shooting method. In general we concluded that the Morse potential solved with numerical methods could accurately produce the vibrational properties and the wavefunction behavior of BaO and SrO molecules from the ground state to the higher states close to the dissociation level.

Upper limb injury in rugby union football: results of a cohort study.

Science.gov (United States)

Usman, Juliana; McIntosh, Andrew Stuart

2013-04-01

There have been few in-depth studies of upper limb injury epidemiology in rugby union football, despite reports that they accounted for between 14% and 28% of all rugby injuries. To report on upper limb injury incidence, injury severity and to identify the risk factors associated with upper limb injuries, for example, level of play, season (years) and playing position. Prospective cohort study across five rugby seasons from 2004 to 2008. Formal rugby competitions-suburban, provincial and international. 1475 adult male rugby players in Colts, Grade and Elite competitions. An upper limb injury resulting in a missed game and its characteristics. A total of 61 598 athletic exposures (AE) and 606 upper limb injuries were recorded. About 66% of the injuries were to the shoulder. The overall upper limb injury incidence rate (IIR) was 9.84 injuries/1000 AE (95% CI 9.06 to 10.62). Statistically significant associations were found between upper limb injuries and level of play; and between shoulder injuries and playing position (p<0.05). No association was found between upper limb and shoulder injuries and study year. The overall upper limb IIR decreased as the level of play increased; 10.74 upper limb injuries/1000 AE (95% CI 9.93 to 11.56) in Colts to 6.07 upper limb injuries/1000 AE (95% CI 5.46 to 6.69) in Elite. The upper limb IIR decreased as the level of play increased indicating that age, level of skill and playing experience may be risk factors for upper limb injury.

Neutron reflectometry with ROG and mechanical vibrations

International Nuclear Information System (INIS)

Well, A.A. van.

1991-11-01

Specifications for the maximum level of vibrational amplitudes at the sample position of the IRI neutron reflectometer ROG are presented. The acceleration and displacement amplitudes in the reactor floor have been measured as a function of frequency. These measured values meet the ROG specifications. (author). 11 figs.; 1 tab

An Overview of Recent Automotive Applications of Active Vibration Control

National Research Council Canada - National Science Library

Kowalczyk, K; Svaricek, F; Bohn, C; Karkosch, H

2004-01-01

.... Continental has developed and implemented prototypes of active mounting systems on various test vehicles and demonstrated that significant reductions in noise and vibration levels are achievable...

Combined effect of noise and vibration produced by high-speed trains on annoyance in buildings.

Science.gov (United States)

Lee, Pyoung Jik; Griffin, Michael J

2013-04-01

The effects of noise and vibration on annoyance in buildings during the passage of a nearby high-speed train have been investigated in a laboratory experiment with recorded train noise and 20 Hz vibration. The noises included the effects of two types of façade: windows-open and windows-closed. Subjects were exposed to six levels of noise and six magnitudes of vibration, and asked to rate annoyance using an 11-point numerical scale. The experiment consisted of four sessions: (1) evaluation of noise annoyance in the absence of vibration, (2) evaluation of total annoyance from simultaneous noise and vibration, (3) evaluation of noise annoyance in the presence of vibration, and (4) evaluation of vibration annoyance in the absence of noise. The results show that vibration did not influence ratings of noise annoyance, but that total annoyance caused by combined noise and vibration was considerably greater than the annoyance caused by noise alone. The noise annoyance and the total annoyance caused by combined noise and vibration were associated with subject self-ratings of noise sensitivity. Two classical models of total annoyance due to combined noise sources (maximum of the single source annoyance or the integration of individual annoyance ratings) provided useful predictions of the total annoyance caused by simultaneous noise and vibration.

Effect of the upper-level decay on the resonantly enhanced four-wave mixing in a modified double-Λ system

International Nuclear Information System (INIS)

Kien, Fam Le; Hakuta, K.

2004-01-01

We study the continuous resonant four-wave mixing in a medium of atoms with a modified double-Λ level configuration. Under the far-off-resonance condition for a pair of levels, we reduce the five-level scheme to an effective three-level scheme, with a two-photon coupling between the two lower levels. We derive the exact steady-state solution to the density-matrix equations for the reduced scheme and obtain the wave-mixing equations for the fields in the continuous-wave regime. We show that the upper-level decay may substantially affect the resonantly enhanced wave-mixing process. We demonstrate that this decay shortens the conversion cycle rather than prolongs it

Excited State Chemistry in the Free Stream of the NASA IHF Arc Jet Facility Observed by Emission Spectroscopy

Science.gov (United States)

Winter, Michael W.; Prabhu, Dinesh K.

2011-01-01

Spectroscopic measurements of non-equilibrium emission were made in the free stream of the 60 megawatts Interaction Heating Facility at NASA Ames Research Center. In the visible near infrared wavelength region, the most prominent emission was from molecular N2, and in the ultra violet region, the spectra were dominated by emission from molecular NO. The only atomic lines observed were those of copper (an erosion product of the electrodes). The bands of the 1st Positive system of N2 (if B is true then A is true) differed significantly from spectra computed spectra assuming only thermal excitation, suggesting overpopulation of the high vibrational states of the B state of N2. Populations of these high vibrational levels (peaking at v (sub upper) equals 13) of the N2 B state were determined by scaling simulated spectra; calculations were performed for each upper vibrational state separately. The experimental-theoretical procedure was repeated for several radial positions away from the nozzle axis to obtain spatial distributions of the upper state populations; rotational symmetry of the flow was assumed in simulations. The overpopulation of the high vibrational levels has been interpreted as the effect of inverse pre-dissociation of neutral atoms in the N2 A state, which populates the N2 B state through a level crossing process at v (sub upper) is greater than 10.

The Efficacy of Anti-vibration Gloves

Science.gov (United States)

Hewitt, Sue; Dong, Ren; McDowell, Tom; Welcome, Daniel

2016-01-01

Anyone seeking to control the risks from vibration transmitted to the hands and arms may contemplate the use of anti-vibration gloves. To make an informed decision about any type of personal protective equipment, it is necessary to have performance data that allow the degree of protection to be estimated. The information provided with an anti-vibration glove may not be easy to understand without some background knowledge of how gloves are tested and does not provide any clear route for estimating likely protection. Some of the factors that influence the potential efficacy of an anti-vibration glove include how risks from hand–arm vibration exposure are assessed, how the standard test for a glove is carried out, the frequency range and direction of the vibration for which protection is sought, how much hand contact force or pressure is applied and the physical limitations due to glove material and construction. This paper reviews some of the background issues that are useful for potential purchasers of anti-vibration gloves. Ultimately, anti-vibration gloves cannot be relied on to provide sufficient and consistent protection to the wearer and before their use is contemplated all other available means of vibration control ought first to be implemented. PMID:27582615

Vibrations in the urban environment controlling 222Rn migration in soils

International Nuclear Information System (INIS)

Wiegand, J.

1998-01-01

Comparable to investigations looking for a connection of 222 Rn and earthquakes, this study shows the influence of subsurface vibrations on the 222 Rn concentration of the soil-gas in urban environments. Generally, the 222 Rn concentration increases through vibrations induced by trains, street-traffic and activities at project sites. The spatial radius of the 222 Rn increase due to vibrations reach highest values at project sites where piled foundations or metal panels are rammed into the ground (> 60 m). Along railway tracks the radius is wider (> 30 m) than along heavy traffic roads ( 222 Rn concentrations in soil-gas due to vibrations is the highest at project sites (53%). Along heavy traffic roads the increase of 222 Rn concentrations by motor vehicle traffic is higher (37%) than that by railway traffic (11.5%). The maximum increase of 400% was observed in a distance of 1 m from a railway track. In the vicinity of railway tracks a difference of the vibration influence according to unconsolidated rock (11.1%) or solid rock (11.8%) was not noticed. Beside this vibration effect, the overall 222 Rn level decreases with increasing distance to the vibration source, but only at locations laying above solid rocks. The observation of the increase of 222 Rn concentrations can be explained by a 'pump effect': the mechanical vibration of soil and mineral particles leads to an upward motion of the whole volume of soil-gas. Therefore, 222 Rn is pumped out of the soil to the atmosphere and as a result the upward transport is increased. (author)

EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on the Tolerable Upper Intake Level of calcium

DEFF Research Database (Denmark)

Tetens, Inge

Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to re-evaluate the safety in use of calcium. The Panel was requested to consider if the Tolerable Upper Intake Level (UL) for calcium established by the SCF in 2003 (2,500 mg...

Attitudes Toward, and Use of, Vibrators in China.

Science.gov (United States)

Jing, Shen; Lay, Alixe; Weis, Laura; Furnham, Adrian

2018-01-02

The current study examined the relationship between traditional masculine traits and attitudes toward vibrator use, actual vibrator use, and frequency of vibrator use in China. In all, 235 Chinese females aged between 16 and 58 years completed a questionnaire regarding attitudes toward, and personal use of, vibrators. The results showed a positive association between masculine traits and attitudes toward women's vibrator use, attitudes toward vibrator use and actual vibrator use, as well as frequency of vibrator use. The findings revealed an indirect path in which masculinity influences actual and frequency of vibrator use through attitudes toward women's vibrator use. Limitations and implications of the study are discussed.

Two-dimensional vibrational-electronic spectroscopy

Science.gov (United States)

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

2015-10-01

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

Two-dimensional vibrational-electronic spectroscopy

Energy Technology Data Exchange (ETDEWEB)

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

2015-10-21

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

BOES: Building Occupancy Estimation System using sparse ambient vibration monitoring

Science.gov (United States)

Pan, Shijia; Bonde, Amelie; Jing, Jie; Zhang, Lin; Zhang, Pei; Noh, Hae Young

2014-04-01

In this paper, we present a room-level building occupancy estimation system (BOES) utilizing low-resolution vibration sensors that are sparsely distributed. Many ubiquitous computing and building maintenance systems require fine-grained occupancy knowledge to enable occupant centric services and optimize space and energy utilization. The sensing infrastructure support for current occupancy estimation systems often requires multiple intrusive sensors per room, resulting in systems that are both costly to deploy and difficult to maintain. To address these shortcomings, we developed BOES. BOES utilizes sparse vibration sensors to track occupancy levels and activities. Our system has three major components. 1) It extracts features that distinguish occupant activities from noise prone ambient vibrations and detects human footsteps. 2) Using a sequence of footsteps, the system localizes and tracks individuals by observing changes in the sequences. It uses this tracking information to identify when an occupant leaves or enters a room. 3) The entering and leaving room information are combined with detected individual location information to update the room-level occupancy state of the building. Through validation experiments in two different buildings, our system was able to achieve 99.55% accuracy for event detection, less than three feet average error for localization, and 85% accuracy in occupancy counting.

Mapping quadrupole collectivity in the Cd isotopes: The breakdown of harmonic vibrational motion

Science.gov (United States)

Garrett, P. E.; Green, K. L.; Bangay, J.; Varela, A. Diaz; Sumithrarachchi, C. S.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D. S.; Bianco, L.; Colosimo, S.; Cross, D. S.; Demand, G. A.; Finlay, P.; Garnsworthy, A. B.; Grinyer, G. F.; Hackman, G.; Kulp, W. D.; Leach, K. G.; Morton, A. C.; Orce, J. N.; Pearson, C. J.; Phillips, A. A.; Schumaker, M. A.; Svensson, C. E.; Triambak, S.; Wong, J.; Wood, J. L.; Yates, S. W.

2011-10-01

The stable Cd isotopes have long been used as paradigms for spherical vibrational motion. Extensive investigations with in-beam γ spectroscopy have resulted in very-well-established level schemes, including many lifetimes or lifetime limits. A programme has been initiated to complement these studies with very-high-statistics β decay using the 8π spectrometer at the TRIUMF radioactive beam facility. The decays of 112In and 112Ag have been studied with an emphasis on the observation of, or the placement of stringent limits on, low-energy branches between potential multi-phonon levels. A lack of suitable 0+ or 2+ three-phonon candidates has been revealed. Further, the sum of the B(E2) strength from spin 0+ and 2+ states up to 3 MeV in excitation energy to the assigned two-phonon levels falls far short of the harmonic-vibrational expectations. This lack of strength points to the failing of collective models based on vibrational phonon structures.

Vibrational Spectroscopy of Chromatographic Interfaces

Energy Technology Data Exchange (ETDEWEB)

Jeanne E. Pemberton

2011-03-10

Chromatographic separations play a central role in DOE-supported fundamental research related to energy, biological systems, the environment, and nuclear science. The overall portfolio of research activities in the Separations and Analysis Program within the DOE Office of Basic Energy Sciences includes support for activities designed to develop a molecular-level understanding of the chemical processes that underlie separations for both large-scale and analytical-scale purposes. The research effort funded by this grant award was a continuation of DOE-supported research to develop vibrational spectroscopic methods to characterize the interfacial details of separations processes at a molecular level.

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.