WorldWideScience

Sample records for vibration isolation mass

  1. Vibration isolation by compliant sensor mounting applied to a coriolis mass-flow meter

    NARCIS (Netherlands)

    van de Ridder, Bert; Hakvoort, Wouter; van Dijk, Johannes

    2014-01-01

    In this paper a vibration isolated design of the Coriolis Mass-Flow Meter (CMFM) is proposed, by introducing a compliant connection between the casing and the tube displacement sensors with the intention to obtain a relative displacement measurement of the fluid conveying tube, dependent on the tube

  2. Vibration Isolation by an Actively Compliantly Mounted Sensor Applied to a Coriolis Mass-Flow Meter

    NARCIS (Netherlands)

    van de Ridder, Bert; Hakvoort, Wouter; van Dijk, Johannes; Lötters, Joost Conrad; de Boer, Andries

    2016-01-01

    In this paper, a vibration isolated design of a Coriolis mass-flow meter (CMFM) is proposed by introducing a compliant connection between the casing and the tube displacement sensors, with the objective to obtain a relative displacement measurement of the fluid conveying tube, dependent on the tube

  3. Vibration isolation for Coriolis Mass-Flow meters

    NARCIS (Netherlands)

    van de Ridder, Bert

    2015-01-01

    A Coriolis Mass-Flow Meter (CMFM) is an active device based on the Coriolis force principle for direct mass-flow measurements, with high accuracy, range-ability and repeatability. The working principle of a CMFM is as follows: a fluid conveying tube is actuated to oscillate at a low amplitude. A

  4. 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.

  5. Using Euler buckling springs for vibration isolation

    CERN Document Server

    Winterflood, J; Blair, D G

    2002-01-01

    Difficulties in obtaining ideal vertical vibration isolation with mechanical springs are identified as being due to the mass of the elastic element which is in turn due to its energy storage requirement. A new technique to minimize this energy is presented - being an Euler column undergoing elastic buckling. The design of a high performance vertical vibration isolation stage based on this technique is presented together with its measured performance.

  6. Using Euler buckling springs for vibration isolation

    International Nuclear Information System (INIS)

    Winterflood, J; Barber, T; Blair, D G

    2002-01-01

    Difficulties in obtaining ideal vertical vibration isolation with mechanical springs are identified as being due to the mass of the elastic element which is in turn due to its energy storage requirement. A new technique to minimize this energy is presented - being an Euler column undergoing elastic buckling. The design of a high performance vertical vibration isolation stage based on this technique is presented together with its measured performance

  7. 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.

  8. Identification and Partial Structural Characterization of Mass Isolated Valsartan and Its Metabolite with Messenger Tagging Vibrational Spectroscopy

    Science.gov (United States)

    Gorlova, Olga; Colvin, Sean M.; Brathwaite, Antonio; Menges, Fabian S.; Craig, Stephanie M.; Miller, Scott J.; Johnson, Mark A.

    2017-08-01

    Recent advances in the coupling of vibrational spectroscopy with mass spectrometry create new opportunities for the structural characterization of metabolites with great sensitivity. Previous studies have demonstrated this scheme on 300 K ions using very high power free electron lasers in the fingerprint region of the infrared. Here we extend the scope of this approach to a single investigator scale as well as extend the spectral range to include the OH stretching fundamentals. This is accomplished by detecting the IR absorptions in a linear action regime by photodissociation of weakly bound N2 molecules, which are attached to the target ions in a cryogenically cooled, rf ion trap. We consider the specific case of the widely used drug Valsartan and two isomeric forms of its metabolite. Advantages and challenges of the cold ion approach are discussed, including disentangling the role of conformers and the strategic choices involved in the selection of the charging mechanism that optimize spectral differentiation among candidate structural isomers. In this case, the Na+ complexes are observed to yield sharp resonances in the high frequency NH and OH stretching regions, which can be used to easily differentiate between two isomers of the metabolite. [Figure not available: see fulltext.

  9. Recent advances in micro-vibration isolation

    Science.gov (United States)

    Liu, Chunchuan; Jing, Xingjian; Daley, Steve; Li, Fengming

    2015-05-01

    Micro-vibration caused by disturbance sources onboard spacecraft can severely degrade the working environment of sensitive payloads. Some notable vibration control methods have been developed particularly for the suppression or isolation of micro-vibration over recent decades. Usually, passive isolation techniques are deployed in aerospace engineering. Active isolators, however, are often proposed to deal with the low frequency vibration that is common in spacecraft. Active/passive hybrid isolation has also been effectively used in some spacecraft structures for a number of years. In semi-active isolation systems, the inherent structural performance can be adjusted to deal with variation in the aerospace environment. This latter approach is potentially one of the most practical isolation techniques for micro-vibration isolation tasks. Some emerging advanced vibration isolation methods that exploit the benefits of nonlinearity have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of the vibration isolation theory and/or methods which were developed, mainly over the last decade, specifically for or potentially could be used for, micro-vibration control.

  10. Vibration isolation of a ship's seat

    Science.gov (United States)

    Agahi, Maryam; Samani, Mehrdad B.; Behzad, Mehdi

    2005-05-01

    Different factors cause vibration. These vibrations make the voyages difficult and reduce comfort and convenience in passenger ships. In this paper, the creating factors of vibration have discussed first, then with mathematical modelling it will be attempted to minimize the vibration over the crew's seat. The modelling consists of a system with two degrees of freedom and by using vibrationisolation with passive method of Tuned Mass Damper (TMD) it will be tried to reduce the vibration over personnel. Moreover using active control systems will be compared with passive systems.

  11. Passive and active vibration isolation systems using inerter

    Science.gov (United States)

    Alujević, N.; Čakmak, D.; Wolf, H.; Jokić, M.

    2018-03-01

    This paper presents a theoretical study on passive and active vibration isolation schemes using inerter elements in a two degree of freedom (DOF) mechanical system. The aim of the work is to discuss basic capabilities and limitations of the vibration control systems at hand using simple and physically transparent models. Broad frequency band dynamic excitation of the source DOF is assumed. The purpose of the isolator system is to prevent vibration transmission to the receiving DOF. The frequency averaged kinetic energy of the receiving mass is used as the metric for vibration isolation quality. It is shown that the use of inerter element in the passive vibration isolation scheme can enhance the isolation effect. In the active case, a feedback disturbance rejection scheme is considered. Here, the error signal is the receiving body absolute velocity which is directly fed to a reactive force actuator between the source and the receiving bodies. In such a scheme, the so-called subcritical vibration isolation problems exist. These problems are characterised by the uncoupled natural frequency of the receiving body larger than the uncoupled natural frequency of the source body. In subcritical vibration isolation problems, the performance of the active control is limited by poor stability margins. This is because the stable feedback gain is restricted in a narrow range between a minimum and a maximum. However, with the inclusion of an inerter in the isolator, one of the two stability margins can be opened. This enables large, theoretically unlimited negative feedback gains and large active damping of the receiving body vibration. A simple expression for the required inertance is derived.

  12. 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.

  13. Vibration Isolation for Parallel Hydraulic Hybrid Vehicles

    Directory of Open Access Journals (Sweden)

    The M. Nguyen

    2008-01-01

    Full Text Available In recent decades, several types of hybrid vehicles have been developed in order to improve the fuel economy and to reduce the pollution. Hybrid electric vehicles (HEV have shown a significant improvement in fuel efficiency for small and medium-sized passenger vehicles and SUVs. HEV has several limitations when applied to heavy vehicles; one is that larger vehicles demand more power, which requires significantly larger battery capacities. As an alternative solution, hydraulic hybrid technology has been found effective for heavy duty vehicle because of its high power density. The mechanical batteries used in hydraulic hybrid vehicles (HHV can be charged and discharged remarkably faster than chemical batteries. This feature is essential for heavy vehicle hybridization. One of the main problems that should be solved for the successful commercialization of HHV is the excessive noise and vibration involving with the hydraulic systems. This study focuses on using magnetorheological (MR technology to reduce the noise and vibration transmissibility from the hydraulic system to the vehicle body. In order to study the noise and vibration of HHV, a hydraulic hybrid subsystem in parallel design is analyzed. This research shows that the MR elements play an important role in reducing the transmitted noise and vibration to the vehicle body. Additionally, locations and orientations of the isolation system also affect the efficiency of the noise and vibration mitigation. In simulations, a skyhook control algorithm is used to achieve the highest possible effectiveness of the MR isolation system.

  14. Active vibration isolation of a rigidly mounted turbo pump

    NARCIS (Netherlands)

    Basten, T.G.H.; Doppenberg, E.J.J.

    2006-01-01

    Manufacturers of precision equipment are constantly aiming at increased accuracy. Elimination of disturbing vibrations is therefore getting more and more important. The technical limitations of passive isolation methods require alternative strategies for vibration reduction, such as active

  15. A Sub-Hertz, Low-Frequency Vibration Isolation Platform

    Science.gov (United States)

    Ortiz, Gerardo, G.; Farr, William H.; Sannibale, Virginio

    2011-01-01

    struts ends are connected in pairs to the base and to the platform, forming an octahedron. The six struts provide the vibration isolation due to the properties of mechanical oscillators that behave as second-order lowpass filters for frequencies above the resonance. At high frequency, the ideal second-order low-pass filter response is spoiled by the distributed mass and the internal modes of membrane and of the platform with its payload.

  16. Active Low-frequency Vertical Vibration Isolation System for Precision Measurements

    Institute of Scientific and Technical Information of China (English)

    WU Kang; LI Gang; HU Hua; WANG Lijun

    2017-01-01

    Low-frequency vertical vibration isolation systems play important roles in precision measurements to reduce seismic and environmental vibration noise.Several types of active vibration isolation systems have been developed.However,few researches focus on how to optimize the test mass install position in order to improve the vibration transmissibility.An active low-frequency vertical vibration isolation system based on an earlier instrument,the Super Spring,is designed and implemented.The system,which is simple and compact,consists of two stages:a parallelogram-shaped linkage to ensure vertical motion,and a simple spring-mass system.The theoretical analysis of the vibration isolation system is presented,including terms erroneously ignored before.By carefully choosing the mechanical parameters according to the above analysis and using feedback control,the resonance frequency of the system is reduced from 2.3 to 0.03 Hz,a reduction by a factor of more than 75.The vibration isolation system is installed as an inertial reference in an absolute gravimeter,where it improved the scatter of the absolute gravity values by a factor of 5.The experimental results verifies the improved performance of the isolation system,making it particularly suitable for precision experiments.The improved vertical vibration isolation system can be used as a prototype for designing high-performance active vertical isolation systems.An improved theoretical model of this active vibration isolation system with beam-pivot configuration is proposed,providing fundamental guidelines for vibration isolator design and assembling.

  17. Improvement of the vibration isolation system for TAMA300

    CERN Document Server

    Takahashi, R

    2002-01-01

    The vibration isolation system for TAMA300 has a vibration isolation ratio large enough to achieve the requirement in the observation band around 300 Hz. At a lower frequency range, it is necessary to reduce the large fluctuation of mirrors for stable operation of the interferometer. With this aim, the mirror suspension systems were modified and an active vibration isolation system using pneumatic actuators was installed. These improvements contributed to the realization of a continuous interferometer lock for more than 24 h.

  18. EFFECTOF ISOLATION WALL USING SCRAP TIRE ON GROUND VIBRATION REDUCTION

    Science.gov (United States)

    Kashimoto, Takahiko; Kashimoto, Yusuke; Hayakawa, Kiyoshi; Matsui, Tamotsu; Fujimoto, Hiroaki

    Some countermeasure methods against the environmental ground vibration caused by some traffic vibrations have been proposed so far. The authors have developed a new type ground vibration isolation wall using scrap tire, and evaluated its effectiveness on the ground vibration reduction by full scale field tests. In this paper, the authors discussed and examined the effectiveness of the developed countermeasure method by two field tests. The one concerns on the effect of scrap tire as soft material of vibration isolation wall, and the other on the effect of the developed countermeasure method practically applied in a residential area close to monorail traffic. As the results, it was elucidated that the ground vibration of 2-3 dB was reduced in case of two times volume of the soft material, the conversion ratio of the vibration energy of the soft material to the kinetic energy was higher than that of the core material of PHC pile, the vibration acceleration of 0.19 - 1.26 gal was reduced by the developed countermeasure method in case of the monorail traffic, and the vibration reduction measured behind the isolation wall agreed well with the proposed theoretical value, together with confirming the effectiveness of the ground vibration isolation wall using scrap tire as the countermeasure method against the environmental ground vibration.

  19. Sensor fusion for active vibration isolation in precision equipment

    NARCIS (Netherlands)

    Tjepkema, D.; van Dijk, Johannes; Soemers, Herman

    2012-01-01

    Sensor fusion is a promising control strategy to improve the performance of active vibration isolation systems that are used in precision equipment. Normally, those vibration isolation systems are only capable of realizing a low transmissibility. Additional objectives are to increase the damping

  20. Synthesis of Optimal Isolation Systems of Hand-Transmitted Vibration

    Directory of Open Access Journals (Sweden)

    Marek Książek

    1997-01-01

    Full Text Available In this article a procedure is presented for the analytical synthesis of optimal vibration isolation for a hand-arm system subjected to stochastic excitation. A general approach is discussed for a selected vibration isolation criterion. The general procedure is illustrated by analytical examples for different hand-arm systems described by their driving-point impedances. The influence of particular forms of excitation and the structure of the vibroisolated hand-arm systems on the resultant vibration isolation is then discussed. Some numerical examples illustrating the procedure have also been included.

  1. Research on Vibration Isolation Systems Used in Laser and Nanotechnologies

    Directory of Open Access Journals (Sweden)

    Justinas Kuncė

    2012-12-01

    Full Text Available The paper discusses the efficiency of a vibration isolation system made of the optical table and two negative-stiffness tables and considers excitation referring to harmonic and nonharmonic methods in the frequency range of 0,2–110 Hz. The article reviews the types and sources of vibrations and types of vibration isolation systems, including those of negative-stiffness. The paper also presents the methodology of experimental tests and proposes research on vibration transmissibility. A composite system consisting of two vibration isolation table having negative stiffness and an air table has been tested. The results and conclusions of experimental analysis are suggested at the end of the article.Article in Lithuanian

  2. Vibration transfers to measure the performance of vibration isolated platforms on site using background noise excitation

    NARCIS (Netherlands)

    Segerink, Franciscus B.; Korterik, Jeroen P.; Offerhaus, Herman L.

    2011-01-01

    This article demonstrates a quick and easy way of quantifying the performance of a vibration-isolated platform. We measure the vibration transfer from floor to table using background noise excitation from the floor. As no excitation device is needed, our setup only requires two identical sensors (in

  3. Active vibration isolation platform on base of magnetorheological elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailov, Valery P., E-mail: mikhailov@bmstu.ru; Bazinenkov, Alexey M.

    2017-06-01

    The article describes the active vibration isolation platform on base of magnetorheological (MR) elastomers. An active damper based on the MR elastomers can be used as an actuator of micro- or nanopositioning for a vibroinsulated object. The MR elastomers give such advantages for active control of vibration as large range of displacements (up to 1 mm), more efficient absorption of the vibration energy, possibility of active control of amplitude-frequency characteristics and positioning with millisecond response speed and nanometer running accuracy. The article presents the results of experimental studies of the most important active damper parameters. Those are starting current, transient time for stepping, transmission coefficient of the vibration displacement amplitude.

  4. Experimental investigation of torsional vibration isolation using Magneto Rheological Elastomer

    Directory of Open Access Journals (Sweden)

    Praveen Shenoy K

    2018-01-01

    Full Text Available Rotating systems suffer from lateral and torsional vibrations which have detrimental effect on the roto-dynamic performance. Many available technologies such as vibration isolators and vibration absorbers deal with the torsional vibrations to a certain extent, however passive isolators and absorbers find less application when the input conditions are dynamic. The present work discusses use of a smart material called as Magneto Rheological Elastomer (MRE, whose properties can be changed based on magnetic field input, as a potential isolator for torsional vibrations under dynamic loading conditions. Carbonyl Iron Particles (CIP of average size 5 μm were mixed with RTV Silicone rubber to form the MRE. The effect of magnetic field on the system parameters was comprehended under impulse loading conditions using a custom built in-house system. Series arrangement of accelerometers were used to differentiate between the torsional and the bending modes of vibration of the system. Impact hammer tests were carried out on the torsional system to study its response, in the presence and absence of magnetic field. The tests revealed a shift in torsional frequency in the presence of magnetic field which elucidates the ability of MRE to work as a potential vibration isolator for torsional systems.

  5. Gerotor and bearing system for whirling mass orbital vibrator

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-02-27

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

  6. 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

  7. 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.

  8. 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.

  9. A 6-DOF vibration isolation system for hydraulic hybrid vehicles

    Science.gov (United States)

    Nguyen, The; Elahinia, Mohammad; Olson, Walter W.; Fontaine, Paul

    2006-03-01

    This paper presents the results of vibration isolation analysis for the pump/motor component of hydraulic hybrid vehicles (HHVs). The HHVs are designed to combine gasoline/diesel engine and hydraulic power in order to improve the fuel efficiency and reduce the pollution. Electric hybrid technology is being applied to passenger cars with small and medium engines to improve the fuel economy. However, for heavy duty vehicles such as large SUVs, trucks, and buses, which require more power, the hydraulic hybridization is a more efficient choice. In function, the hydraulic hybrid subsystem improves the fuel efficiency of the vehicle by recovering some of the energy that is otherwise wasted in friction brakes. Since the operation of the main component of HHVs involves with rotating parts and moving fluid, noise and vibration are an issue that affects both passengers (ride comfort) as well as surrounding people (drive-by noise). This study looks into the possibility of reducing the transmitted noise and vibration from the hydraulic subsystem to the vehicle's chassis by using magnetorheological (MR) fluid mounts. To this end, the hydraulic subsystem is modeled as a six degree of freedom (6-DOF) rigid body. A 6-DOF isolation system, consisting of five mounts connected to the pump/motor at five different locations, is modeled and simulated. The mounts are designed by combining regular elastomer components with MR fluids. In the simulation, the real loading and working conditions of the hydraulic subsystem are considered and the effects of both shock and vibration are analyzed. The transmissibility of the isolation system is monitored in a wide range of frequencies. The geometry of the isolation system is considered in order to sustain the weight of the hydraulic system without affecting the design of the chassis and the effectiveness of the vibration isolating ability. The simulation results shows reduction in the transmitted vibration force for different working cycles of

  10. Experimental Study of Vibration Isolation Characteristics of a Geometric Anti-Spring Isolator

    Directory of Open Access Journals (Sweden)

    Lixun Yan

    2017-07-01

    Full Text Available In order to realize low-frequency vibration isolation, a novel geometric anti-spring isolator consisting of several cantilever blade springs are developed in this paper. The optimal design parameters of the geometric anti-spring isolator for different nonlinear geometric parameters are theoretically obtained. The transmissibility characteristic of the geometric anti-spring isolator is investigated through mathematical simulation. A geometric anti-spring isolator with a nonlinear geometric parameter of 0.92 is designed and its vibration isolation performance and nonlinearity characteristic is experimentally studied. The experiment results show that the designed isolator has good low-frequency vibration isolation performance, of which the initial isolation frequency is less than 3.6 Hz when the load weight is 21 kg. The jump phenomena of the response of the isolator under linear frequency sweep excitation are observed, and this result demonstrates that the geometric anti-spring isolator has a complex nonlinearity characteristics with the increment of excitation amplitude. This research work provides a theoretical and experimental basis for the application of the nonlinear geometric anti-spring low-frequency passive vibration isolation technology in engineering practice.

  11. Marshak Lectureship: Vibrational properties of isolated color centers in diamond

    Science.gov (United States)

    Alkauskas, Audrius

    In this talk we review our recent work on first-principles calculations of vibrational properties of isolated defect spin qubits and single photon emitters in diamond. These properties include local vibrational spectra, luminescence lineshapes, and electron-phonon coupling. They are key in understanding physical mechanisms behind spin-selective optical initialization and read-out, quantum efficiency of single-photon emitters, as well as in the experimental identification of as yet unknown centers. We first present the methodology to calculate and analyze vibrational properties of effectively isolated defect centers. We then apply the methodology to the nitrogen-vacancy and the silicon-vacancy centers in diamond. First-principles calculations yield important new insights about these important defects. Work performed in collaboration with M. W. Doherty, A. Gali, E. Londero, L. Razinkovas, and C. G. Van de Walle. Supported by the Research Council of Lithuania (Grant M-ERA.NET-1/2015).

  12. Microgravity Active Vibration Isolation System on Parabolic Flights

    Science.gov (United States)

    Dong, Wenbo; Pletser, Vladimir; Yang, Yang

    2016-07-01

    The Microgravity Active Vibration Isolation System (MAIS) aims at reducing on-orbit vibrations, providing a better controlled lower gravity environment for microgravity physical science experiments. The MAIS will be launched on Tianzhou-1, the first cargo ship of the China Manned Space Program. The principle of the MAIS is to suspend with electro-magnetic actuators a scientific payload, isolating it from the vibrating stator. The MAIS's vibration isolation capability is frequency-dependent and a decrease of vibration of about 40dB can be attained. The MAIS can accommodate 20kg of scientific payload or sample unit, and provide 30W of power and 1Mbps of data transmission. The MAIS is developed to support microgravity scientific experiments on manned platforms in low earth orbit, in order to meet the scientific requirements for fluid physics, materials science, and fundamental physics investigations, which usually need a very quiet environment, increasing their chances of success and their scientific outcomes. The results of scientific experiments and technology tests obtained with the MAIS will be used to improve future space based research. As the suspension force acting on the payload is very small, the MAIS can only be operative and tested in a weightless environment. The 'Deutsches Zentrum für Luft- und Raumfahrt e.V.' (DLR, German Aerospace Centre) granted a flight opportunity to the MAIS experiment to be tested during its 27th parabolic flight campaign of September 2015 performed on the A310 ZERO-G aircraft managed by the French company Novespace, a subsidiary of the 'Centre National d'Etudes Spatiales' (CNES, French Space Agency). The experiment results confirmed that the 6 degrees of freedom motion control technique was effective, and that the vibration isolation performance fulfilled perfectly the expectations based on theoretical analyses and simulations. This paper will present the design of the MAIS and the experiment results obtained during the

  13. Experimental Investigations on the Dynamic Behaviour of O-Type Wire-Cable Vibration Isolators

    Directory of Open Access Journals (Sweden)

    Hong-Xia Wang

    2015-01-01

    Full Text Available A series of periodic loading experiments were carried out on the O-type wire-cable vibration isolators. The isolators were loaded under shear, roll, and tension-compression loadings. When subjected to shear and roll loads, the restoring force-deformation curves generated by the isolators formed symmetric hysteresis loops. However, when the isolators were loaded with tension-compression loads, the isolator produced asymmetric hysteresis loops. It is found through the experiment that the dynamic characteristics of the isolator are determined by the loading amplitude as well as the geometric parameters of the isolator while they are almost independent of loading frequency within the testing frequency range. Based on the experimental data, the dynamic response of the isolator was modeled by a modified normalized Bouc-Wen model. The parameters of this model were identified through an identification procedure that does not involve any nonlinear iterative algorithms. Comparison between the identification results and the experimental data suggests that the identification method is effective. With the model and the identified parameters, the frequency response of an O-type wire-cable vibration isolator-mass system was evaluated. Typical nonlinear response behaviors were found when the isolator was used in tension-compression mode while the response appears to be similar to that of a linear system when the isolator was used in shear and roll mode.

  14. Environmental vibration reduction utilizing an array of mass scatterers

    DEFF Research Database (Denmark)

    Peplow, Andrew; Andersen, Lars Vabbersgaard; Bucinskas, Paulius

    2017-01-01

    .g. concrete or stone blocks, specially designed brick walls, etc.). The natural frequencies of vibration for such blocks depend on the local ground stiffness and on the mass of the blocks which can be chosen to provide resonance at specified frequencies. This work concerns the effectiveness of such “blocking......Ground vibration generated by rail and road traffic is a major source of environmental noise and vibration pollution in the low-frequency range. A promising and cost effective mitigation method can be the use of heavy masses placed as a periodic array on the ground surface near the road or track (e...

  15. Wire rope isolators for vibration isolation of equipment and structures – A review

    International Nuclear Information System (INIS)

    Balaji, P S; Rahman, M E; Lau, H H; Moussa, Leblouba

    2015-01-01

    Vibrations and shocks are studied using various techniques and analyzed to predict their detrimental effect on the equipment and structures. In cases, where the effects of vibration become unacceptable, it may cause structural damage and affect the operation of the equipment. Hence, adding a discrete system to isolate the vibration from source becomes necessary. The Wire Rope Isolator (WRI) can be used to effectively isolate the system from disturbing vibrations. The WRI is a type of passive isolator that exhibits nonlinear behavior. It consists of stranded wire rope held between two metal retainer bars and the metal wire rope is made up of individual wire strands that are in frictional contact with each other, hence, it is a kind of friction-type isolator. This paper compiles the research work on wire rope isolators. This paper presents the research work under two categories, namely monotonic and cyclic loading behaviors of WRI. The review also discusses the different terminologies associated with vibration isolation system and highlights the comparison between various isolation systems. (paper)

  16. Active vibration isolation of high precision machines

    CERN Document Server

    Collette, C; Artoos, K; Hauviller, C

    2010-01-01

    This paper provides a review of active control strategies used to isolate high precisionmachines (e.g. telescopes, particle colliders, interferometers, lithography machines or atomic force microscopes) from external disturbances. The objective of this review is to provide tools to develop the best strategy for a given application. Firstly, the main strategies are presented and compared, using single degree of freedom models. Secondly, the case of huge structures constituted of a large number of elements, like particle colliders or segmented telescopes, is considered.

  17. Free Vibration of Rectangular Plates with Attached Discrete Sprung Masses

    Directory of Open Access Journals (Sweden)

    Ding Zhou

    2012-01-01

    Full Text Available A direct approach is used to derive the exact solution for the free vibration of thin rectangular plates with discrete sprung masses attached. The plate is simply supported along two opposite edges and elastically supported along the two other edges. The elastic support can represent a range of boundary conditions from free to clamped supports. Considering only the compatibility of the internal forces between the plate and the sprung masses, the equations of the coupled vibration of the plate-spring-mass system are derived. The exact expressions for mode and frequency equations of the coupled vibration of the plate and sprung masses are determined. The solutions converge steadily and monotonically to exact values. The correctness and accuracy of the solutions are demonstrated through comparison with published results. A parametric study is undertaken focusing on the plate with one or two sprung masses. The results can be used as a benchmark for further investigation.

  18. Two-sensor control in active vibration isolation using hard mounts

    NARCIS (Netherlands)

    Beijen, M.A.; Tjepkema, D.; van Dijk, J.

    To isolate precision machines from floor vibrations, active vibration isolators are often applied. In this paper, a two-sensor control strategy, based on acceleration feedback and force feedback, is proposed for an active vibration isolator using a single-axis active hard mount. The hard mount

  19. Two-sensor control in active vibration isolation using hard mounts

    NARCIS (Netherlands)

    Beijen, M.A.; Tjepkema, D.; van Dijk, Johannes

    2014-01-01

    To isolate precision machines from floor vibrations, active vibration isolators are often applied. In this paper, a two-sensor control strategy, based on acceleration feedback and force feedback, is proposed for an active vibration isolator using a single-axis active hard mount. The hard mount

  20. Numerical and experimental analysis of a vibration isolator equipped with a negative stiffness system

    Science.gov (United States)

    Palomares, E.; Nieto, A. J.; Morales, A. L.; Chicharro, J. M.; Pintado, P.

    2018-02-01

    This paper presents a Negative Stiffness System (NSS) based on a set of two double-acting pneumatic linear actuators (PLA). The NSS is added to a system with a single degree of freedom, which consists of a sprung mass and a pneumatic spring. One end of each PLA is jointed to the sprung mass while the other end is jointed to the vibrating frame. In addition, the PLAs are symmetrically arranged so that they remain horizontal while the sprung mass is in static conditions. When the rear chamber is pressurised, the vertical component of the force applied by the PLAs will work against the pneumatic spring reducing the dynamic resonance frequency of the overall system. Experimental tests and simulations showed improvements regarding sprung mass isolation in comparison to the passive system without NSS, decreasing the resonance frequency by up to 58 % and improving the vibration attenuation for different experimental excitations.

  1. Vibration isolation of cable tray hangers

    International Nuclear Information System (INIS)

    Pearce, B.K.; Dixon, M.W.; Jackson, J.E.

    1984-01-01

    Analytical and experimental investigations have been performed to partially evaluate the feasibility of using much more flexible support systems than those presently used to support electrical and control cables in nuclear power plants. This approach, which entails introducing a flexible element between the support and the component being supported, could apply to many types of support systems, such as for piping, HVAC or even bridges. However, this paper addresses the specific case of cable tray hangers only. It was found that, for appropriate stiffness and damping characteristics, this concept could be used effectively to isolate cable trays from hanger motion caused by seismic excitation and to significantly reduce hanger loads while maintaining reasonable displacements. This was found to be true for all variations in system parameters investigated. Thus, the flexible hanger concept appears to offer much potential. However, additional study including full-scale testing and more detailed analysis must be completed before the concept can be validated for plant use

  2. Inficon Transpector MPH Mass Spectrometer Random Vibration Test Report

    Science.gov (United States)

    Santiago-Bond, Jo; Captain, Janine

    2015-01-01

    The purpose of this test report is to summarize results from the vibration testing of the INFICON Transpector MPH100M model Mass Spectrometer. It also identifies requirements satisfied, and procedures used in the test. As a payload of Resource Prospector, it is necessary to determine the survivability of the mass spectrometer to proto-qualification level random vibration. Changes in sensitivity of the mass spectrometer can be interpreted as a change in alignment of the instrument. The results of this test will be used to determine any necessary design changes as the team moves forward with flight design.

  3. Vibration isolation and damping in high precision equipment

    Science.gov (United States)

    Bukkems, B.; Ruijl, T.; Simons, J.

    2017-06-01

    All systems located in a laboratory environment or factory are subject to disturbances. These disturbances can either come from the surroundings, e.g. floor-induced vibrations, or from the system itself, e.g. stage-induced vibrations. In many cases it is needed to minimize the effect of these disturbances. This can either be done by isolating the system from its disturbance source or by applying damping to the system. In this paper we present various cases in which we have effectively reduced the impact of disturbances on the system's performance, either by improving its isolation system, by minimizing the impact of stage reaction forces, or by designing polymer damping into the system.

  4. Research on typical topologies of a tubular horizontal-gap passive magnetic levitation vibration isolator

    Directory of Open Access Journals (Sweden)

    Zhou Yiheng

    2017-01-01

    Full Text Available Magnetic levitation vibration isolators have attracted more and more attention in the field of high-precision measuring and machining equipment. In this paper, we describe a tubular horizontal-gap passive magnetic levitation vibration isolator. Four typical topologies of the tubular horizontal-gap passive magnetic levitation vibration isolator are proposed. The analytical expression of magnetic force is derived. The relationship between levitation force, force density, force ripple and major structural parameters are analysed by finite element method, which is conductive to the design and optimization of the tubular horizontal-gap passive magnetic levitation vibration isolator. The force characteristics of different topologies of the tubular horizontal-gap passive magnetic levitation vibration isolator are compared and evaluated from the aspect of force density, force ripple and manufacturability. In comparison with conventional passive magnetic levitation vibration isolators, the proposed tubular horizontal-gap passive magnetic levitation vibration isolator shows advantage in higher force density.

  5. Vibration Isolation System Using Negative Stiffness(Advances in Motion and Vibration Control Technology)

    OpenAIRE

    水野, 毅; 高崎, 正也

    2003-01-01

    A new vibration isolation system using negative stiffness realized by active control technique is proposed in this paper. The serial connection of a normal spring and a suspension system with negative stiffness enables the isolation system to have low stiffness for vibration from the ground and high (theoretically infinite) stiffness against direct disturbance acting on the isolation table. A control method of realizing negative stiffness with a linear actuator is presented in an analytical f...

  6. Study of the Mechanical Properties and Vibration Isolation Performance of a Molecular Spring Isolator

    Directory of Open Access Journals (Sweden)

    Muchun Yu

    2016-01-01

    Full Text Available Molecular Spring Isolator (MSI is a novel passive vibration isolation technique, providing High-Static-Low-Dynamic (HSLD stiffness based on the use of molecular spring material. The molecular spring material is a solid-liquid mixture consisting of water and hydrophobic nanoporous materials. Under a certain level of external pressure, water molecules can intrude into the hydrophobic pores of nanoporous materials, developing an additional solid-liquid interface. Such interfaces are able to store, release, and transform mechanical energy, providing properties like mechanical spring. Having been only recently developed, the basic mechanic properties of a MSI have not been studied in depth. This paper focuses on the stiffness influence factors, the dynamic frequency response, and the vibration isolation performance of a MSI; these properties help engineers to design MSIs for different engineering applications. First, the working mechanism of a MSI is introduced from a three-dimensional general view of the water infiltration massive hydrophobic nanoporous pores. Next, a wide range of influence factors on the stiffness properties of MSI are studied. In addition, the frequency response functions (FRFs of the MSI vibration isolation system are studied utilizing the matching method based on equivalent piecewise linear (EPL system. Finally, the vibration isolation properties of MSI are evaluated by force transmissibility.

  7. A tubular dielectric elastomer actuator: Fabrication, characterization and active vibration isolation

    DEFF Research Database (Denmark)

    Sarban, R.; Jones, R. W.; Mace, B. R.

    2011-01-01

    This contribution reviews the fabrication, characterization and active vibration isolation performance of a core-free rolled tubular dielectric elastomer (DE) actuator, which has been designed and developed by Danfoss PolyPower A/S. PolyPower DE material, PolyPower (TM), is produced in thin sheets...... of 80 mu m thickness with corrugated metallic electrodes on both sides. Tubular actuators are manufactured by rolling the DE sheets in a cylindrical shape. The electromechanical characteristics of such actuators are modeled based on equilibrium pressure equation. The model is validated with experimental...... the dominant dynamic characteristics of the core-free tubular actuator. It has been observed that all actuators have similar dynamic characteristics in a frequency range up to 1 kHz. A tubular actuator is then used to provide active vibration isolation (AVI) of a 250 g mass subject to shaker generated 'ground...

  8. Static and dynamic stability of pneumatic vibration isolators and systems of isolators

    Science.gov (United States)

    Ryaboy, Vyacheslav M.

    2014-01-01

    Pneumatic vibration isolation is the most widespread effective method for creating vibration-free environments that are vital for precise experiments and manufacturing operations in optoelectronics, life sciences, microelectronics, nanotechnology and other areas. The modeling and design principles of a dual-chamber pneumatic vibration isolator, basically established a few decades ago, continue to attract attention of researchers. On the other hand, behavior of systems of such isolators was never explained in the literature in sufficient detail. This paper covers a range of questions essential for understanding the mechanics of pneumatic isolation systems from both design and application perspectives. The theory and a model of a single standalone isolator are presented in concise form necessary for subsequent analysis. Then the dynamics of a system of isolators supporting a payload is considered with main attention directed to two aspects of their behavior: first, the static stability of payloads with high positions of the center of gravity; second, dynamic stability of the feedback system formed by mechanical leveling valves. The direct method of calculating the maximum stable position of the center of gravity is presented and illustrated by three-dimensional stability domains; analytic formulas are given that delineate these domains. A numerical method for feedback stability analysis of self-leveling valve systems is given, and the results are compared with the analytical estimates for a single isolator. The relation between the static and dynamic phenomena is discussed.

  9. The effect of beam inclination on the performance of a passive vibration isolator using buckled beams

    International Nuclear Information System (INIS)

    Mori, H; Waters, T; Saotome, N; Nagamine, T; Sato, Y

    2016-01-01

    Passive vibration isolators are desired to have both high static stiffness to support large static load and low local stiffness to reduce the displacement transmissibility at frequencies greater than resonance. Utilization of a vertical buckled beam as a spring component is one way to realize such a stiffness characteristic since it exhibits a smaller ratio of local stiffness to static stiffness than that of a linear spring. This paper investigates the behaviour of a vibration isolator using inclined beams as well as vertical ones and examines the effect of beam inclination for the purpose of improving the isolation performance. The experimental system investigated has an isolated mass which is supported by a combination of two types of beams: buckled beams and constraining beams. The buckled beams can be inclined from the vertical by attachment devices, and the constraining beams are employed to prevent off-axis motion of the isolated mass. The results demonstrate that the inclination of the buckled beams reduces the resonance frequency and improves the displacement transmissibility at frequencies greater than resonance. (paper)

  10. Mass and stiffness calibration of nanowires using thermally driven vibration

    International Nuclear Information System (INIS)

    Kiracofe, D R; Raman, A; Yazdanpanah, M M

    2011-01-01

    Cantilevered or suspended nanowires show promise for force or mass sensing applications due to their small mass, high force sensitivity and high frequency bandwidth. To use these as quantitative sensors, their bending stiffness or mass must be calibrated experimentally, often using thermally driven vibration. However, this can be difficult because nanowires are slightly asymmetric, which results in two spatially orthogonal bending eigenmodes with closely spaced frequencies. This asymmetry presents problems for traditional stiffness calibration methods, which equate the measured thermal vibration spectrum near a resonance to that of a single eigenmode. Moreover, the principal axes may be arbitrarily rotated with respect to the measurement direction. In this work, the authors propose a method for calibrating the bending stiffness and mass of such nanowires' eigenmodes using a single measurement taken at an arbitrary orientation with respect to the principal axes.

  11. Skyrmion vibrational energies together with a generalized mass term

    International Nuclear Information System (INIS)

    Davies, Merlin C.; Marleau, Luc

    2009-01-01

    We study various properties of a one-parameter mass term for the Skyrme model, originating from the works of Kopeliovich, Piette and Zakrzewski [V. B. Kopeliovich, B. Piette, and W. J. Zakrzewski, Phys. Rev. D 73, 014006 (2006).], through the use of axially symmetric solutions obtained numerically by simulated-annealing. These solutions allow us to observe asymptotic behaviors of the B=2 binding energies that differ to those previously obtained [B. Piette and W. J. Zakrzewski, Phys. Rev. D 77, 074009 (2008).]. We also decipher the characteristics of three distinct vibrational modes that appear as eigenstates of the vibrational Hamiltonian. This analysis further examine the assertion that the one-parameter mass term offers a better account of baryonic matter than the traditional mass term.

  12. Multistage position-stabilized vibration isolation system for neutron interferometry

    Science.gov (United States)

    Arif, Muhammad; Brown, Dennis E.; Greene, Geoffrey L.; Clothier, R.; Littrell, K.

    1994-10-01

    A two stage, position stabilized vibration isolation system has been constructed and is now in operation at the Cold Neutron Research Facility of the National Institute of Standards and Technology, Gaithersburg, MD. The system employs pneumatic isolators with a multiple input/multiple output pneumatic servo system based upon pulse width modulation control loops. The first stage consists of a 40,000 kg reinforced concrete table supported by pneumatic isolators. A large environmentally isolated laboratory enclosure rests on the concrete table. The second stage consists of a 3000 kg granite optical table located within the enclosure and supported by another set of pneumatic isolators. The position of the two stages is monitored by proximity sensors and inclinometers with 12 degrees of freedom. The system controls 12 independent pneumatic airsprings. The signals from these sensors are fed into a personal computer based control system. The control system has maintained the position of the two stages to better than 1 micrometers in translation and 5 (mu) rad in orientation for a period of a few months. A description of the system and its characteristics is given.

  13. Compact vibration isolation and suspension for Australian International Gravitational Observatory: local control system.

    Science.gov (United States)

    Dumas, Jean-Charles; Barriga, Pablo; Zhao, Chunnong; Ju, Li; Blair, David G

    2009-11-01

    High performance vibration isolators are required for ground based gravitational wave detectors. To attain very high performance at low frequencies we have developed multistage isolators for the proposed Australian International Gravitational Observatory detector in Australia. New concepts in vibration isolation including self-damping, Euler springs, LaCoste springs, Roberts linkages, and double preisolation require novel sensors and actuators. Double preisolation enables internal feedback to be used to suppress low frequency seismic noise. Multidegree of freedom control systems are required to attain high performance. Here we describe the control components and control systems used to control all degrees of freedom. Feedback forces are injected at the preisolation stages and at the penultimate suspension stage. There is no direct actuation on test masses. A digital local control system hosted on a digital signal processor maintains alignment and position, corrects drifts, and damps the low frequency linear and torsional modes without exciting the very high Q-factor test mass suspension. The control system maintains an optical cavity locked to a laser with a high duty cycle even in the absence of an autoalignment system. An accompanying paper presents the mechanics of the system, and the optical cavity used to determine isolation performance. A feedback method is presented, which is expected to improve the residual motion at 1 Hz by more than one order of magnitude.

  14. Compact vibration isolation and suspension for Australian International Gravitational Observatory: Local control system

    Science.gov (United States)

    Dumas, Jean-Charles; Barriga, Pablo; Zhao, Chunnong; Ju, Li; Blair, David G.

    2009-11-01

    High performance vibration isolators are required for ground based gravitational wave detectors. To attain very high performance at low frequencies we have developed multistage isolators for the proposed Australian International Gravitational Observatory detector in Australia. New concepts in vibration isolation including self-damping, Euler springs, LaCoste springs, Roberts linkages, and double preisolation require novel sensors and actuators. Double preisolation enables internal feedback to be used to suppress low frequency seismic noise. Multidegree of freedom control systems are required to attain high performance. Here we describe the control components and control systems used to control all degrees of freedom. Feedback forces are injected at the preisolation stages and at the penultimate suspension stage. There is no direct actuation on test masses. A digital local control system hosted on a digital signal processor maintains alignment and position, corrects drifts, and damps the low frequency linear and torsional modes without exciting the very high Q-factor test mass suspension. The control system maintains an optical cavity locked to a laser with a high duty cycle even in the absence of an autoalignment system. An accompanying paper presents the mechanics of the system, and the optical cavity used to determine isolation performance. A feedback method is presented, which is expected to improve the residual motion at 1 Hz by more than one order of magnitude.

  15. Supports for shock, vibration and seismic isolation for tube networks

    International Nuclear Information System (INIS)

    Prisecaru, Ilie; Serban, Viorel; Sandrea Madalina

    2005-01-01

    The paper presents a solution for diminishing the shocks, vibrations and seismic movements in pipe networks, with a simultaneous reduction in the general stress conditions in piping and supports. Total removal or reduction of vibrations is a hard problem which was not yet tackled either theoretically, in the sense of an analytical procedure for the analysis of occurrence and development of shocks and vibrations in complex systems, or practically, since the current supports and dampers cannot provide enough damping within all the frequency ranges met in the technical domain. Stiffness of classical supports do not allow always satisfactory source isolation to prevent propagation from environment of shocks and vibrations, Considering the actual condition met in the nuclear power plants, power plants and thermal power plants, etc. this paper represents a major practical aid because it provides new solutions for diminishing shocks, vibrations and seismic movements. Aiming at diminishing the effects of vibrations in pipe networks, this paper presents the results obtained in the design, construction and testing of new types of supports that include sandwich type components made up of elastic blade packages with controlled distortion provided by the central and peripheral stiff parts called SERB. With the new type of supports, the control of the distortion at static and dynamic loads and the thermal displacements is achieved by the relative movement among the sandwich structure subassemblies and by the sandwich structure distortion controlled by the central and peripheral distorting parts that generate a non - linear geometric response which has an easily controllable stiffness and damping, due to their non - linear geometric behavior. The supports of the new type are adjustable to the load and distortion level without overstressing the component material, due to a non - linear geometric behavior while the contact pressure among the blades is limited to pre-set values. Due

  16. Discrete optimization of isolator locations for vibration isolation systems: An analytical and experimental investigation

    Energy Technology Data Exchange (ETDEWEB)

    Ponslet, E.R.; Eldred, M.S. [Sandia National Labs., Albuquerque, NM (United States). Structural Dynamics Dept.

    1996-05-17

    An analytical and experimental study is conducted to investigate the effect of isolator locations on the effectiveness of vibration isolation systems. The study uses isolators with fixed properties and evaluates potential improvements to the isolation system that can be achieved by optimizing isolator locations. Because the available locations for the isolators are discrete in this application, a Genetic Algorithm (GA) is used as the optimization method. The system is modeled in MATLAB{trademark} and coupled with the GA available in the DAKOTA optimization toolkit under development at Sandia National Laboratories. Design constraints dictated by hardware and experimental limitations are implemented through penalty function techniques. A series of GA runs reveal difficulties in the search on this heavily constrained, multimodal, discrete problem. However, the GA runs provide a variety of optimized designs with predicted performance from 30 to 70 times better than a baseline configuration. An alternate approach is also tested on this problem: it uses continuous optimization, followed by rounding of the solution to neighboring discrete configurations. Results show that this approach leads to either infeasible or poor designs. Finally, a number of optimized designs obtained from the GA searches are tested in the laboratory and compared to the baseline design. These experimental results show a 7 to 46 times improvement in vibration isolation from the baseline configuration.

  17. Post-capture vibration suppression of spacecraft via a bio-inspired isolation system

    Science.gov (United States)

    Dai, Honghua; Jing, Xingjian; Wang, Yu; Yue, Xiaokui; Yuan, Jianping

    2018-05-01

    Inspired by the smooth motions of a running kangaroo, a bio-inspired quadrilateral shape (BIQS) structure is proposed to suppress the vibrations of a free-floating spacecraft subject to periodic or impulsive forces, which may be encountered during on-orbit servicing missions. In particular, the BIQS structure is installed between the satellite platform and the capture mechanism. The dynamical model of the BIQS isolation system, i.e. a BIQS structure connecting the platform and the capture mechanism at each side, is established by Lagrange's equations to simulate the post-capture dynamical responses. The BIQS system suffering an impulsive force is dealt with by means of a modified version of Lagrange's equations. Furthermore, the classical harmonic balance method is used to solve the nonlinear dynamical system subject to periodic forces, while for the case under impulsive forces the numerical integration method is adopted. Due to the weightless environment in space, the present BIQS system is essentially an under-constrained dynamical system with one of its natural frequencies being identical to zero. The effects of system parameters, such as the number of layers in BIQS, stiffness, assembly angle, rod length, damping coefficient, masses of satellite platform and capture mechanism, on the isolation performance of the present system are thoroughly investigated. In addition, comparisons between the isolation performances of the presently proposed BIQS isolator and the conventional spring-mass-damper (SMD) isolator are conducted to demonstrate the advantages of the present isolator. Numerical simulations show that the BIQS system has a much better performance than the SMD system under either periodic or impulsive forces. Overall, the present BIQS isolator offers a highly efficient passive way for vibration suppressions of free-floating spacecraft.

  18. A Novel Dual–Parallelogram Passive Rocking Vibration Isolator: A Theoretical Investigation and Experiment

    Directory of Open Access Journals (Sweden)

    Shuai Wang

    2017-04-01

    Full Text Available Vibration isolators with quasi-zero stiffness (QZS perform well for low- or ultra-low-frequency vibration isolation. This paper proposes a novel dual-parallelogram passive rocking vibration isolator with QZS that could effectively attenuate in-plane disturbances with low-frequency vibration. First, a kinematic model of the proposed vibration isolator was established and four linear spring configuration schemes were developed to implement the QZS. Next, an optimal scheme with good high-static-low-dynamic stiffness (HSLDS performance was obtained through comparison and analysis, and used as a focus for the QZS model. Subsequently, a dynamic model-based Lagrangian equation that considered the spring stiffness and damping and the influence of the payload gravity center on the vibration isolation system was developed, and an average approach was used to analyze the vibration transmissibility. Finally, the prototype and test system were constructed. A comparison of the simulation and experimental results showed that this novel passive rocking vibration isolator could bolster a heavy payload. Experimentally, the vibration amplitude decreased by 53% and 86% under harmonic disturbances of 0.08 Hz and 0.35 Hz, respectively, suggesting the great practical applicability of this presented vibration isolator.

  19. Active Vibration Isolation Devices with Inertial Servo Actuators

    Science.gov (United States)

    Melik-Shakhnazarov, V. A.; Strelov, V. I.; Sofiyanchuk, D. V.; Tregubenko, A. A.

    2018-03-01

    The use of active vibration isolation devices (AVIDs) in aerospace engineering is subject to the following restrictions. First, the volume for installing additional devices is always limited in instrument racks and compartments. Secondly, in many cases, it is impossible to add supports for servo actuators for fundamental or design considerations. In the paper, it has been shown that this problem can be solved if the inertial servo actuators are used in AVIDs instead of reference actuators. A transfer function has been theoretically calculated for an AVID controlled by inertial actuators. It has been shown that the volume of a six-mode single-housing AVID with inertial actuators can be 2-2.5 times smaller than that of devices with support actuators.

  20. Effects of Proof Mass Geometry on Piezoelectric Vibration Energy Harvesters

    Directory of Open Access Journals (Sweden)

    Abdul Hafiz Alameh

    2018-05-01

    Full Text Available Piezoelectric energy harvesters have proven to have the potential to be a power source in a wide range of applications. As the harvester dimensions scale down, the resonance frequencies of these devices increase drastically. Proof masses are essential in micro-scale devices in order to decrease the resonance frequency and increase the strain along the beam to increase the output power. In this work, the effects of proof mass geometry on piezoelectric energy harvesters are studied. Different geometrical dimension ratios have significant impact on the resonance frequency, e.g., beam to mass lengths, and beam to mass widths. A piezoelectric energy harvester has been fabricated and tested operating at a frequency of about 4 kHz within the audible range. The responses of various prototypes were studied, and an optimized T-shaped piezoelectric vibration energy harvester design is presented for improved performance.

  1. Force Limited Random Vibration Test of TESS Camera Mass Model

    Science.gov (United States)

    Karlicek, Alexandra; Hwang, James Ho-Jin; Rey, Justin J.

    2015-01-01

    The Transiting Exoplanet Survey Satellite (TESS) is a spaceborne instrument consisting of four wide field-of-view-CCD cameras dedicated to the discovery of exoplanets around the brightest stars. As part of the environmental testing campaign, force limiting was used to simulate a realistic random vibration launch environment. While the force limit vibration test method is a standard approach used at multiple institutions including Jet Propulsion Laboratory (JPL), NASA Goddard Space Flight Center (GSFC), European Space Research and Technology Center (ESTEC), and Japan Aerospace Exploration Agency (JAXA), it is still difficult to find an actual implementation process in the literature. This paper describes the step-by-step process on how the force limit method was developed and applied on the TESS camera mass model. The process description includes the design of special fixtures to mount the test article for properly installing force transducers, development of the force spectral density using the semi-empirical method, estimation of the fuzzy factor (C2) based on the mass ratio between the supporting structure and the test article, subsequent validating of the C2 factor during the vibration test, and calculation of the C.G. accelerations using the Root Mean Square (RMS) reaction force in the spectral domain and the peak reaction force in the time domain.

  2. Viscoelasticity of new generation thermoplastic polyurethane vibration isolators

    Science.gov (United States)

    Bek, Marko; Betjes, Joris; von Bernstorff, Bernd-Steffen; Emri, Igor

    2017-12-01

    This paper presents the analysis of pressure dependence of three thermoplastic polyurethane (TPU) materials on vibration isolation. The three TPU Elastollan® materials are 1190A, 1175A, and 1195D. The aim of this investigation was to analyze how much the performance of isolation can be enhanced using patented Dissipative bulk and granular systems technology. The technology uses granular polymeric materials to enhance materials properties (without changing its chemical or molecular composition) by exposing them to "self-pressurization," which shifts material energy absorption maxima toward lower frequencies, to match the excitation frequency of dynamic loading to which a mechanical system is exposed. Relaxation experiments on materials were performed at different isobaric and isothermal states to construct mastercurves, the time-temperature-pressure interrelation was modeled using the Fillers-Moonan-Tschoegl model. Dynamic material functions, related to isolation stiffness and energy absorption, were determined with the Schwarzl approximation. An increase in stiffness and energy absorption at selected hydrostatic pressure, compared to its stiffness and energy absorption at ambient conditions, is represented with κk(p, ω), defining the increase in stiffness and κd(p, ω), defining the increase in energy absorption. The study showed that close to the glassy state, moduli of 1190A and 1195D are about 6-9 times higher compared to 1175A, whereas their properties at ambient conditions are, for all practical purposes, the same. TPU 1190A turns out to be most sensitive to pressure: at 300 MPa its properties are shifted for 5.5 decades, while for 1195D and 1175A this shift is only 3.5 and 1.5 decades, respectively. In conclusion, the stiffness and energy absorption of isolation may be increased with pressure for about 100 times for 1190A and 1195D and for about 10 times for 1175A.

  3. Vibration isolation of a building against earthquake, airplane crash and blast

    International Nuclear Information System (INIS)

    Mischke, J.; Hilpert, H.J.; Henkel, F.O.

    1986-01-01

    The influence of three different support concepts on the vibration responses of a building to the load cases earthquake, airplane crash and blast is numerically investigated. Compared are the three concepts: the standard version of a double shell structure with a combined base for inner and outer building without isolation system; the same building with isolation system between foundation slab and soil, as vibration isolation known so far; and as a third concept a double shell structure with completely separated inner and outer building, where the isolation system is placed between the two parts of the building. The results show that, compared to the standard concept, the third concept leads to a nearly complete isolation of shock-induced vibrations, and to a reduction of the vibrations caused by an earthquake, comparable to the reduction in the isolation concept known so far. (orig.)

  4. Nonlinear dynamic analysis of 2-DOF nonlinear vibration isolation floating raft systems with feedback control

    International Nuclear Information System (INIS)

    Li Yingli; Xu Daolin; Fu Yiming; Zhou Jiaxi

    2012-01-01

    In this paper, the average method is adopted to analysis dynamic characteristics of nonlinear vibration isolation floating raft system with feedback control. The analytic results show that the purposes of reducing amplitude of oscillation and complicating the motion can be achieved by adjusting properly the system parameters, exciting frequency and control gain. The conclusions can provide some available evidences for the design and improvement of both the passive and active control of the vibration isolation systems. By altering the exciting frequency and control gain, complex motion of the system can be obtained. Numerical simulations show the system exhibits period vibration, double period vibration and quasi-period motion.

  5. Vibration induced sliding: theory and experiment for a beam with a spring-loaded mass

    DEFF Research Database (Denmark)

    Miranda, Erik; Thomsen, Jon Juel

    1998-01-01

    The study sets up a simple model for predicting vibration induced sliding of mass, and provides quantitative experimental evidence for the validity of the model. The results lend confidence to recent theoretical developments on using vibration induced sliding for passive vibration damping, and co...

  6. Near-Source Error Sensor Strategies for Active Vibration Isolation of Machines

    NARCIS (Netherlands)

    Beijers, C.A.J.; Basten, T.G.H.; de Boer, Andries; van den Brink, D.R.; Verheij, J.W.; Sas, P; de Munck, M.

    2004-01-01

    Due to lightweight construction of vehicles and ships, the reduction of structure borne interior noise problems with passive isolation of engine vibrations might be not sufficient. To improve the isolation, a combination of passive and active isolation techniques can be used (so-called hybrid

  7. Damping control of micromachined lowpass mechanical vibration isolation filters using electrostatic actuation with electronic signal processing

    Science.gov (United States)

    Dean, Robert; Flowers, George; Sanders, Nicole; MacAllister, Ken; Horvath, Roland; Hodel, A. S.; Johnson, Wayne; Kranz, Michael; Whitley, Michael

    2005-05-01

    Some harsh environments, such as those encountered by aerospace vehicles and various types of industrial machinery, contain high frequency/amplitude mechanical vibrations. Unfortunately, some very useful components are sensitive to these high frequency mechanical vibrations. Examples include MEMS gyroscopes and resonators, oscillators and some micro optics. Exposure of these components to high frequency mechanical vibrations present in the operating environment can result in problems ranging from an increased noise floor to component failure. Passive micromachined silicon lowpass filter structures (spring-mass-damper) have been demonstrated in recent years. However, the performance of these filter structures is typically limited by low damping (especially if operated in near-vacuum environments) and a lack of tunability after fabrication. Active filter topologies, such as piezoelectric, electrostrictive-polymer-film and SMA have also been investigated in recent years. Electrostatic actuators, however, are utilized in many micromachined silicon devices to generate mechanical motion. They offer a number of advantages, including low power, fast response time, compatibility with silicon micromachining, capacitive position measurement and relative simplicity of fabrication. This paper presents an approach for realizing active micromachined mechanical lowpass vibration isolation filters by integrating an electrostatic actuator with the micromachined passive filter structure to realize an active mechanical lowpass filter. Although the electrostatic actuator can be used to adjust the filter resonant frequency, the primary application is for increasing the damping to an acceptable level. The physical size of these active filters is suitable for use in or as packaging for sensitive electronic and MEMS devices, such as MEMS vibratory gyroscope chips.

  8. Self-tuning MIMO disturbance feedforward control for active hard-mounted vibration isolators

    NARCIS (Netherlands)

    Beijen, M.A.; Heertjes, M.F.; Van Dijk, J.; Hakvoort, W. B.J.

    2018-01-01

    © 2017 Elsevier Ltd This paper proposes a multi-input multi-output (MIMO) disturbance feedforward controller to improve the rejection of floor vibrations in active vibration isolation systems for high-precision machinery. To minimize loss of performance due to model uncertainties, the feedforward

  9. Self-tuning MIMO disturbance feedforward control for active hard-mounted vibration isolators

    NARCIS (Netherlands)

    Beijen, M.A.; Heertjes, M.F.; van Dijk, J.W.; Hakvoort, W.B.J.

    2018-01-01

    This paper proposes a multi-input multi-output (MIMO) disturbance feedforward controller to improve the rejection of floor vibrations in active vibration isolation systems for high-precision machinery. To minimize loss of performance due to model uncertainties, the feedforward controller is

  10. Mathematical Modeling of a Transient Vibration Control Strategy Using a Switchable Mass Stiffness Compound System

    Directory of Open Access Journals (Sweden)

    Diego Francisco Ledezma-Ramirez

    2014-01-01

    Full Text Available A theoretical control strategy for residual vibration control resulting from a shock pulse is studied. The semiactive control strategy is applied in a piecewise linear compound model and involves an on-off logic to connect and disconnect a secondary mass stiffness system from the primary isolation device, with the aim of providing high energy dissipation for lightly damped systems. The compound model is characterized by an energy dissipation mechanism due to the inelastic collision between the two masses and then viscous damping is introduced and its effects are analyzed. The objective of the simulations is to evaluate the transient vibration response in comparison to the results for a passive viscously damped single degree-of-freedom system considered as the benchmark or reference case. Similarly the decay in the compound system is associated with an equivalent decay rate or logarithmic decrement for direct comparison. It is found how the compound system provides improved isolation compared to the passive system, and the damping mechanisms are explained.

  11. Magnetorheological elastomer vibration isolation of tunable three-dimensional locally resonant acoustic metamaterial

    Science.gov (United States)

    Xu, Zhenlong; Tong, Jie; Wu, Fugen

    2018-03-01

    Magnetorheological elastomers (MREs) are used as cladding in three-dimensional locally resonant acoustic metamaterial (LRAM) cores. The metamaterial units are combined into a vibration isolator. Two types of LRAMs, namely, cubic and spherical kernels, are constructed. The finite element method is used to analyze the elastic band structures, transmittances, and vibration modes of the incident elastic waves. Results show that the central position and width of the LRAM elastic bandgap can be controlled by the application of an external magnetic field; furthermore, they can be adjusted by changing the MRE cladding thickness. These methods contribute to the design of metamaterial MRE vibration isolators.

  12. 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)

  13. An adaptive left–right eigenvector evolution algorithm for vibration isolation control

    International Nuclear Information System (INIS)

    Wu, T Y

    2009-01-01

    The purpose of this research is to investigate the feasibility of utilizing an adaptive left and right eigenvector evolution (ALREE) algorithm for active vibration isolation. As depicted in the previous paper presented by Wu and Wang (2008 Smart Mater. Struct. 17 015048), the structural vibration behavior depends on both the disturbance rejection capability and mode shape distributions, which correspond to the left and right eigenvector distributions of the system, respectively. In this paper, a novel adaptive evolution algorithm is developed for finding the optimal combination of left–right eigenvectors of the vibration isolator, which is an improvement over the simultaneous left–right eigenvector assignment (SLREA) method proposed by Wu and Wang (2008 Smart Mater. Struct. 17 015048). The isolation performance index used in the proposed algorithm is defined by combining the orthogonality index of left eigenvectors and the modal energy ratio index of right eigenvectors. Through the proposed ALREE algorithm, both the left and right eigenvectors evolve such that the isolation performance index decreases, and therefore one can find the optimal combination of left–right eigenvectors of the closed-loop system for vibration isolation purposes. The optimal combination of left–right eigenvectors is then synthesized to determine the feedback gain matrix of the closed-loop system. The result of the active isolation control shows that the proposed method can be utilized to improve the vibration isolation performance compared with the previous approaches

  14. Seismic isolation floor and vibration control equipment for nuclear power plant

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  15. Vibration isolation design for periodically stiffened shells by the wave finite element method

    Science.gov (United States)

    Hong, Jie; He, Xueqing; Zhang, Dayi; Zhang, Bing; Ma, Yanhong

    2018-04-01

    Periodically stiffened shell structures are widely used due to their excellent specific strength, in particular for aeronautical and astronautical components. This paper presents an improved Wave Finite Element Method (FEM) that can be employed to predict the band-gap characteristics of stiffened shell structures efficiently. An aero-engine casing, which is a typical periodically stiffened shell structure, was employed to verify the validation and efficiency of the Wave FEM. Good agreement has been found between the Wave FEM and the classical FEM for different boundary conditions. One effective wave selection method based on the Wave FEM has thus been put forward to filter the radial modes of a shell structure. Furthermore, an optimisation strategy by the combination of the Wave FEM and genetic algorithm was presented for periodically stiffened shell structures. The optimal out-of-plane band gap and the mass of the whole structure can be achieved by the optimisation strategy under an aerodynamic load. Results also indicate that geometric parameters of stiffeners can be properly selected that the out-of-plane vibration attenuates significantly in the frequency band of interest. This study can provide valuable references for designing the band gaps of vibration isolation.

  16. Design and Analysis of Shock and Random Vibration Isolation of Operating Hard Disk Drive in Harsh Environment

    Directory of Open Access Journals (Sweden)

    Hendri Harmoko

    2009-01-01

    Full Text Available An effective vibration isolation system is important for hard disk drives (HDD used in a harsh mechanical environment. This paper describes how to design, simulate, test and evaluate vibration isolation systems for operating HDD subjected to severe shock and random vibrations based on military specifications MIL-STD-810E. The well-defined evaluation criteria proposed in this paper can be used to effectively assess the performance of HDD vibration isolation system. Design concepts on how to achieve satisfactory shock and vibration isolation for HDD are described. The concepts are tested and further enhanced by the two design case studies presented here. It is shown that an effective vibration isolation system, that will allow a HDD to operate well when subjected to severe shock and random vibration, is feasible.

  17. A new vibration isolation bed stage with magnetorheological dampers for ambulance vehicles

    International Nuclear Information System (INIS)

    Chae, Hee Dong; Choi, Seung-Bok

    2015-01-01

    The vibration experienced in an ambulance can lead to secondary injury to a patient and discourage a paramedic from providing emergency care. In this study, with the goal of resolving this problem, a new vibration isolation bed stage associated with magnetorheological (MR) dampers is proposed to ensure ride quality as well as better care for the patient while he/she is being transported. The bed stage proposed in this work can isolate vibrations in the vertical, rolling and pitching directions to reflect the reality that occurs in the ambulance. Firstly, an appropriate-sized MR damper is designed based on the field-dependent rheological properties of MR fluid, and the damping force characteristics of a MR damper are evaluated as a function of the current. A mechanical model of the proposed vibration isolation bed stage is then established to derive the governing equations of motion. Subsequently, a sliding mode controller is formulated to control the vibrations caused from the imposed excitation signals; those signals are directly measured using a real ambulance subjected to bump-and-curve road conditions. Using the controller based on the dynamic motion of the bed stage, the vibration control performance is evaluated in both the vertical and pitch directions. It is demonstrated that the magnitude of the vibration in the patient compartment of the ambulance can be significantly reduced by applying an input current to the MR dampers installed for the new bed stage. (technical note)

  18. A novel magnetorheological elastomer isolator with negative changing stiffness for vibration reduction

    International Nuclear Information System (INIS)

    Yang, J; Sun, S S; Li, W H; Alici, G; Du, H; Deng, H X

    2014-01-01

    Magneto-rheological elastomers (MREs) have attracted notable credits in the development of smart isolators and absorbers due to their controllable stiffness and damping properties. For the purpose of mitigating unwanted structural and/or machinery vibrations, the traditional MRE-based isolators have been generally proven effective because the MR effect can increase the stiffness when the magnetic field is strengthened. This study presents a novel MRE isolator that experienced reduced stiffness when the applied current was increased. This innovative work was accomplished by applying a hybrid magnet (electromagnet and permanent magnets) onto a multilayered MRE structure. To characterise this negative changing stiffness concept, a multilayered MRE isolator with a hybrid magnet was first designed, fabricated and then tested to measure its properties. An obvious reduction of the effective stiffness and natural frequency of the proposed MRE isolator occurred when the current was continuously adjusted. This device could also work as a conventional MRE isolator as its effective stiffness and natural frequency also increased when a negative current was applied. Further testing was carried out on a one-degree-of-freedom system to assess how effectively this device could isolate vibration. In this experiment, two cases were considered; in each case, the vibration of the primary system was obviously attenuated under ON-OFF control logic, thus demonstrating the feasibility of this novel design as an alternative adaptive vibration isolator. (paper)

  19. Active and passive vibration isolation in piezoelectric phononic rods with external voltage excitation

    Directory of Open Access Journals (Sweden)

    Qicheng Zhang

    2017-05-01

    Full Text Available Active piezoelectric materials are applied to one-dimensional phononic crystals, for the control of longitudinal vibration propagation both in active and passive modes. Based on the electromechanical coupling between the acoustical vibration and electric field, the electromechanical equivalent method is taken to theoretically predict the transmission spectrum of the longitudinal vibration. It is shown that the phononic rod can suppress the vibration efficiently at the frequencies of interest, by actively optimizing the motions of piezoelectric elements. In an illustrated phononic rod of 11.2cm long, active tunable isolations of more than 20dB at low frequencies (500Hz-14kHz are generated by controlling the excitation voltages of piezoelectric elements. Meanwhile, passive fixed isolation at high frequencies (14k-63kHz are presented by its periodicity characteristics. Finite element simulations and vibration experiments on the rod demonstrate the effectiveness of the approach in terms of its vibration isolation capabilities and tunable characteristics. This phononic rod can be manufactured easily and provides numerous potential applications in designing isolation mounts and platforms.

  20. Improved hybrid isolator with maglev actuator integrated in air spring for active-passive isolation of ship machinery vibration

    Science.gov (United States)

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

    2017-10-01

    A hybrid isolator consisting of maglev actuator and air spring is proposed and developed for application in active-passive vibration isolation system of ship machinery. The dynamic characteristics of this hybrid isolator are analyzed and tested. The stability and adaptability of this hybrid isolator to shock and swing in the marine environment are improved by a compliant gap protection technique and a disengageable suspended structure. The functions of these new engineering designs are proved by analytical verification and experimental validation of the designed stiffness of such a hybrid isolator, and also by shock adaptability testing of the hybrid isolator. Finally, such hybrid isolators are installed in an engineering mounting loaded with a 200-kW ship diesel generator, and the broadband and low-frequency sinusoidal isolation performance is tested.

  1. Re-tuning tuned mass dampers using ambient vibration measurements

    International Nuclear Information System (INIS)

    Hazra, B; Sadhu, A; Narasimhan, S; Lourenco, R

    2010-01-01

    Deterioration, accidental changes in the operating conditions, or incorrect estimates of the structure modal properties lead to de-tuning in tuned mass dampers (TMDs). To restore optimal performance, it is necessary to estimate the modal properties of the system, and re-tune the TMD to its optimal state. The presence of closely spaced modes and a relatively large amount of damping in the dominant modes renders the process of identification difficult. Furthermore, the process of estimating the modal properties of the bare structure using ambient vibration measurements of the structure with the TMD is challenging. In order to overcome these challenges, a novel identification and re-tuning algorithm is proposed. The process of identification consists of empirical mode decomposition to separate the closely spaced modes, followed by the blind identification of the remaining modes. Algorithms for estimating the fundamental frequency and the mode shape of the primary structure necessary for re-tuning the TMD are proposed. Experimental results from the application of the proposed algorithms to identify and re-tune a laboratory structure TMD system are presented

  2. 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.

  3. 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.

  4. Semi-active variable stiffness vibration control of vehicle seat suspension using an MR elastomer isolator

    International Nuclear Information System (INIS)

    Du, Haiping; Li, Weihua; Zhang, Nong

    2011-01-01

    This paper presents a study on continuously variable stiffness control of vehicle seat suspension using a magnetorheological elastomer (MRE) isolator. A concept design for an MRE isolator is proposed in the paper and its behavior is experimentally evaluated. An integrated seat suspension model, which includes a quarter-car suspension and a seat suspension with a driver body model, is used to design a sub-optimal H ∞ controller for an active isolator. The desired control force generated by this active isolator is then emulated by the MRE isolator through its continuously variable stiffness property when the actuating condition is met. The vibration control effect of the MRE isolator is evaluated in terms of driver body acceleration responses under both bump and random road conditions. The results show that the proposed control strategy achieves better vibration reduction performance than conventional on–off control

  5. Vibration isolation using nonlinear damping implemented by a feedback-controlled MR damper

    International Nuclear Information System (INIS)

    Ho, C; Lang, Z Q; Billings, S A; Sapiński, B

    2013-01-01

    The main problem of using a conventional linear damper on a vibration isolation system is that the reduction of the resonant peak in many cases inevitably results in the degradation of the high-frequency transmissibility. Instead of using active control methods which normally depend on the model of the controlled plant and where unmodelled dynamics may induce stability concerns, recent studies have revealed that optimal vibration isolation over a wide frequency range can be achieved by using nonlinear damping. The present study is concerned with the realization of the ideal nonlinear damping characteristic using a feedback-controlled MR damper. Both simulation and experimental studies are conducted to demonstrate the advantages of the simple but effective vibration control strategy. This research work has significant implications for the effective use of MR dampers in the vibration control of a wide range of engineering systems. (paper)

  6. The study and analysis of point-to-point vibration isolation and its utility to seismic base isolator

    International Nuclear Information System (INIS)

    Mehboob, M.; Qureshi, A.S.

    2001-01-01

    This paper presents systematic approach to regarding the piece wise vibration isolation generally termed as point-to-point vibration isolation system, and its broad spectrum-utilities to an economic seismic base isolation. Transfer of curves for coulomb damped i.e. softening damper flexible mountings are presented and the utility has been proved equally good for both rigidly and elastically coupled damping. It is clearly shown that the very closest solutions are easily obtainable for both slipping and sticking nature of phases of the motion. This eliminates the conventional and conceptual approximations based on the linearization of the damping. This new concept will not endanger-super-structure if mounted on such isolation systems. (author)

  7. Experimental and Theoretical Vibrational Spectra of Sideridiol Isolated from Sideritis Species

    Science.gov (United States)

    Kilic, Turgut; Sagir, Züleyha Ozer; Carikci, Sema; Azizoğlu, Akın

    2017-12-01

    Sideridiol ( ent-7α,18β-dihydroxykaur-15-ene) one of the ent-kaurene diterpenoid, is isolated from the genus Sideritis L. belongs to the family of Lamiaceae. The vibrational frequencies of sideridiol in the ground state have been calculated using the Density Functional Theory (DFT) method with the 6-31G( d) and 6 31+G( d, p) basis sets. The calculated vibrational frequencies have been compared with that of obtained experimental IR spectrum.

  8. Recent results of seismic isolation study in CRIEPI: Tests on seismic isolation elements, vibration tests and observations

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Katsuhiko; Shiojiri, Hiroo; Mazda, Taiji; Ohtori, Yasuki [Abiko Research Laboratory, Central Research Institute of Electric Power Industry (Japan); Aoyagi, Sakae [Central Research Institute of Electric Power Industry (Japan)

    1992-07-01

    Seismic isolation is expected to be effective in raising reliability during earthquake, reducing cost, enlarging and promoting the design standardization of electric power facilities. In Japan, it has been applied to several buildings. However it is considered that more research is needed to verify the reliability and effectiveness of seismic isolation for fast breeder reactors. In the preliminary study of isolation concepts for FBRs the horizontal base isolation of buildings was investigated in detail. The laminated rubber bearings were considered to be most suitable isolation system. Tests on large scale models of rubber bearing and vibration test of base isolation system have been conducted as well as the earthquake response observation of isolated buildings were conducted.

  9. Recent results of seismic isolation study in CRIEPI: Tests on seismic isolation elements, vibration tests and observations

    International Nuclear Information System (INIS)

    Ishida, Katsuhiko; Shiojiri, Hiroo; Mazda, Taiji; Ohtori, Yasuki; Aoyagi, Sakae

    1992-01-01

    Seismic isolation is expected to be effective in raising reliability during earthquake, reducing cost, enlarging and promoting the design standardization of electric power facilities. In Japan, it has been applied to several buildings. However it is considered that more research is needed to verify the reliability and effectiveness of seismic isolation for fast breeder reactors. In the preliminary study of isolation concepts for FBRs the horizontal base isolation of buildings was investigated in detail. The laminated rubber bearings were considered to be most suitable isolation system. Tests on large scale models of rubber bearing and vibration test of base isolation system have been conducted as well as the earthquake response observation of isolated buildings were conducted

  10. Adaptive active vibration isolation – A control perspective

    Directory of Open Access Journals (Sweden)

    Landau Ioan Doré

    2015-01-01

    The paper will review a number of recent developments for adaptive feedback compensation of multiple unknown and time-varying narrow band disturbances and for adaptive feedforward compensation of broad band disturbances in the presence of the inherent internal positive feedback caused by the coupling between the compensator system and the measurement of the image of the disturbance. Some experimental results obtained on a relevant active vibration control system will illustrate the performance of the various algorithms presented.

  11. Mounting Systems for Structural Members, Fastening Assemblies Thereof, and Vibration Isolation Systems Including the Same

    Science.gov (United States)

    Young, Ken (Inventor); Hindle, Timothy (Inventor); Barber, Tim Daniel (Inventor)

    2016-01-01

    Mounting systems for structural members, fastening assemblies thereof, and vibration isolation systems including the same are provided. Mounting systems comprise a pair of mounting brackets, each clamped against a fastening assembly forming a mounting assembly. Fastening assemblies comprise a spherical rod end comprising a spherical member having a through opening and an integrally threaded shaft, first and second seating members on opposite sides of the spherical member and each having a through opening that is substantially coaxial with the spherical member through opening, and a partially threaded fastener that threadably engages each mounting bracket forming the mounting assembly. Structural members have axial end portions, each releasably coupled to a mounting bracket by the integrally threaded shaft. Axial end portions are threaded in opposite directions for permitting structural member rotation to adjust a length thereof to a substantially zero strain position. Structural members may be vibration isolator struts in vibration isolation systems.

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

    Science.gov (United States)

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

    2017-01-01

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

  13. Vibration characteristics of the seismically isolated building supported by the elastomers and the elasto-plastic dampers

    International Nuclear Information System (INIS)

    Mazda, Taiji; Shiojiri, Hiroo; Aoyagi, Sakae; Sawada, Yoshihiro; Kawai, Nobuyasu; Harada, Osamu; Ohtsuka, Susume; Abe, Isamu.

    1989-01-01

    Recently, the seismic isolation has become one of the popular methods in the design of important structures or equipment against the earthquakes. However, the demonstration data on reliability of seismically isolated structures are not enough, therefore it is expected to accumulate such data. Based on the above recognition, the vibration tests of a base isolated building were carried out in Tsukuba Science City. After that, many earthquake records have been obtained at the building, and they made clear the dynamic characteristics of the structure. In order to make clear the dynamic behavior of the building, furthermore, seismic response analyses were executed by using Lumped Mass model, and the results of the analyses roughly agreed with the observed results. (author)

  14. Parametric Design and Multiobjective Optimization of Maglev Actuators for Active Vibration Isolation System

    Directory of Open Access Journals (Sweden)

    Qianqian Wu

    2014-05-01

    Full Text Available The microvibration has a serious impact on science experiments on the space station and on image quality of high resolution satellites. As an important component of the active vibration isolation platform, the maglev actuator has a large stroke and exhibits excellent isolating performance benefiting from its noncontact characteristic. A maglev actuator with good linearity was designed in this paper. Fundamental features of the maglev actuator were obtained by finite element simulation. In order to minimize the coil weight and the heat dissipation of the maglev actuator, parametric design was carried out and multiobjective optimization based on the genetic algorithm was adopted. The optimized actuator has better mechanical properties than the initial one. Active vibration isolation platforms for different-scale payload were designed by changing the arrangement of the maglev actuators. The prototype to isolate vibration for small-scale payload was manufactured and the experiments for verifying the characteristics of the actuators were set up. The linearity of the actuator and the mechanical dynamic response of the vibration isolation platform were obtained. The experimental results highlight the effectiveness of the proposed design.

  15. Compact vibration isolation and suspension for Australian International Gravitational Observatory: Performance in a 72 m Fabry Perot cavity

    Science.gov (United States)

    Barriga, P.; Dumas, J. C.; Woolley, A. A.; Zhao, C.; Blair, D. G.

    2009-11-01

    This paper describes the first demonstration of vibration isolation and suspension systems, which have been developed with view to application in the proposed Australian International Gravitational Observatory. In order to achieve optimal performance at low frequencies new components and techniques have been combined to create a compact advanced vibration isolator structure. The design includes two stages of horizontal preisolation and one stage of vertical preisolation with resonant frequencies ˜100 mHz. The nested structure facilitates a compact design and enables horizontal preisolation stages to be configured to create a superspring configuration, where active feedback can enable performance close to the limit set by seismic tilt coupling. The preisolation stages are combined with multistage three-dimensional (3D) pendulums. Two isolators suspending mirror test masses have been developed to form a 72 m optical cavity with finesse ˜700 in order to test their performance. The suitability of the isolators for use in suspended optical cavities is demonstrated through their ease of locking, long term stability, and low residual motion. An accompanying paper presents the local control system and shows how simple upgrades can substantially improve residual motion performance.

  16. Power enhancing by reversing mode sequence in tuned mass-spring unit attached vibration energy harvester

    Directory of Open Access Journals (Sweden)

    Jae Eun Kim

    2013-07-01

    Full Text Available We propose a vibration energy harvester consisting of an auxiliary frequency-tuned mass unit and a piezoelectric vibration energy harvesting unit for enhancing output power. The proposed integrated system is so configured that its out-of-phase mode can appear at the lowest eigenfrequency unlike in the conventional system using a tuned unit. Such an arrangement makes the resulting system distinctive: enhanced output power at or near the target operating frequency and very little eigenfrequency separation, not observed in conventional eigenfrequency-tuned vibration energy harvesters. The power enhancement of the proposed system is theoretically examined with and without tip mass normalization or footprint area normalization.

  17. Multi-resonant electromagnetic shunt in base isolation for vibration damping and energy harvesting

    Science.gov (United States)

    Pei, Yalu; Liu, Yilun; Zuo, Lei

    2018-06-01

    This paper investigates multi-resonant electromagnetic shunts applied to base isolation for dual-function vibration damping and energy harvesting. Two multi-mode shunt circuit configurations, namely parallel and series, are proposed and optimized based on the H2 criteria. The root-mean-square (RMS) value of the relative displacement between the base and the primary structure is minimized. Practically, this will improve the safety of base-isolated buildings subjected the broad bandwidth ground acceleration. Case studies of a base-isolated building are conducted in both the frequency and time domains to investigate the effectiveness of multi-resonant electromagnetic shunts under recorded earthquake signals. It shows that both multi-mode shunt circuits outperform traditional single mode shunt circuits by suppressing the first and the second vibration modes simultaneously. Moreover, for the same stiffness ratio, the parallel shunt circuit is more effective at harvesting energy and suppressing vibration, and can more robustly handle parameter mistuning than the series shunt circuit. Furthermore, this paper discusses experimental validation of the effectiveness of multi-resonant electromagnetic shunts for vibration damping and energy harvesting on a scaled-down base isolation system.

  18. The interior working mechanism and temperature characteristics of a fluid based micro-vibration isolator

    Science.gov (United States)

    Wang, Jie; Zhao, Shougen; Wu, Dafang; Jing, Xingjian

    2016-01-01

    Micro-vibration isolation is a hot topic in spacecraft vibration control, and fluid based vibration isolators alternatively provide a good and reliable solution to this challenging issue. In this paper, a novel fluid based micro-vibration isolator (FBMVI) is investigated. According to its inherent working principle and deformation pattern, the generation mechanisms of the damping and stiffness characteristics are derived, which are nonlinear functions of the environmental temperature. Then a lumped parameter model which is expressed by the physical design parameters (PDPs) is constructed, and the corresponding performance objective indices (POIs) are also obtained by applying the equivalence of mechanical impedance. Based on the finite element analysis of the internal damping component, a single variable method is further adopted to carry out the parametric study, and the influences of each PDP on the POIs are analyzed in details. Finally, experiments are conducted to identify the variation of fluid bulk modulus with the outside environmental temperature, and to validate the performance of the isolator under different temperature environments. The tested results show great consistence compared with the predicted tendencies of the parametric study. The results of this study can provide a very useful insight into and/or an important guidance for the design and application of this type of FBMVIs in engineering practice.

  19. A combined dynamic analysis method for geometrically nonlinear vibration isolators with elastic rings

    Science.gov (United States)

    Hu, Zhan; Zheng, Gangtie

    2016-08-01

    A combined analysis method is developed in the present paper for studying the dynamic properties of a type of geometrically nonlinear vibration isolator, which is composed of push-pull configuration rings. This method combines the geometrically nonlinear theory of curved beams and the Harmonic Balance Method to overcome the difficulty in calculating the vibration and vibration transmissibility under large deformations of the ring structure. Using the proposed method, nonlinear dynamic behaviors of this isolator, such as the lock situation due to the coulomb damping and the usual jump resulting from the nonlinear stiffness, can be investigated. Numerical solutions based on the primary harmonic balance are first verified by direct integration results. Then, the whole procedure of this combined analysis method is demonstrated and validated by slowly sinusoidal sweeping experiments with different amplitudes of the base excitation. Both numerical and experimental results indicate that this type of isolator behaves as a hardening spring with increasing amplitude of the base excitation, which makes it suitable for isolating both steady-state vibrations and transient shocks.

  20. The investigation of added masses and damping factors for vibrations of tube and tube bundles in fluid

    International Nuclear Information System (INIS)

    Sinyavskii, V.F.; Fedotovskii, V.S.; Kukhtin, A.B.

    1977-01-01

    The vibrations of single cylinders in fluid being surrounded by the solid walls of different form as well as the bundles of cylindric rods have been considered in this report. A model is proposed for hydrodynamic damping of vibrations and the analytic solution of a problem concerning damping of cylinder vibrations in fluid surrounded by a concentric shell. It has been shown that the fluid viscosity and vibration frequency influence the value of the fluid added mass and the damping factor of vibrations

  1. Vibration of a string against multiple spring-mass-damper stoppers

    Science.gov (United States)

    Shin, Ji-Hwan; Talib, Ezdiani; Kwak, Moon K.

    2018-02-01

    When a building sways due to strong wind or an earthquake, the elevator rope can undergo resonance, resulting in collision with the hoist-way wall. In this study, a hard stopper and a soft stopper comprised of a spring-mass-damper system installed along the hoist-way wall were considered to prevent the string from undergoing excessive vibrations. The collision of the string with multiple hard stoppers and multiple spring-mass-damper stoppers was investigated using an analytical method. The result revealed new formulas and computational algorithms that are suitable for simulating the vibration of the string against multiple stoppers. The numerical results show that the spring-mass-damper stopper is more effective in suppressing the vibrations of the string and reducing structural failure. The proposed algorithms were shown to be efficient to simulate the motion of the string against a vibration stopper.

  2. Vibration Isolation Platform for Long Range Optical Communications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Optical communication links provide higher data transfer rates with lower mass, power, and volume than conventional radio-frequency links. For deep space...

  3. Intermediate coupling vibrational descriptions of odd mass gold isotopes

    CERN Document Server

    Vieu, C; Paar, V

    1976-01-01

    The theoretical analysis of /sup 193-195/Au levels is semi qualitatively performed in the frame of the intermediate coupling vibrational models of Kisslinger-Sorensen and Alaga. From the comparison between the experimental data and the corresponding predictions of the two models, conclusions are drawn on the influence of the clusters and broken pairs.

  4. Whole body vibration improves body mass, flexibility and strength in ...

    African Journals Online (AJOL)

    Objectives. This study aimed to determine the effectiveness of whole body vibration (WBV) training for promoting healthrelated physical fitness in sedentary adults. Design. A non-randomised sampling technique was used with an equivalent match-pair comparison group, pre- and posttest design. Volunteers were gathered ...

  5. Investigation on active vibration isolation of a Stewart platform with piezoelectric actuators

    Science.gov (United States)

    Wang, Chaoxin; Xie, Xiling; Chen, Yanhao; Zhang, Zhiyi

    2016-11-01

    A Stewart platform with piezoelectric actuators is presented for micro-vibration isolation. The Jacobi matrix of the Stewart platform, which reveals the relationship between the position/pointing of the payload and the extensions of the six struts, is derived by kinematic analysis. The dynamic model of the Stewart platform is established by the FRF (frequency response function) synthesis method. In the active control loop, the direct feedback of integrated forces is combined with the FxLMS based adaptive feedback to dampen vibration of inherent modes and suppress transmission of periodic vibrations. Numerical simulations were conducted to prove vibration isolation performance of the Stewart platform under random and periodical disturbances, respectively. In the experiment, the output consistencies of the six piezoelectric actuators were measured at first and the theoretical Jacobi matrix as well as the feedback gain of each piezoelectric actuator was subsequently modified according to the measured consistencies. The direct feedback loop was adjusted to achieve sufficient active damping and the FxLMS based adaptive feedback control was adopted to suppress vibration transmission in the six struts. Experimental results have demonstrated that the Stewart platform can achieve 30 dB attenuation of periodical disturbances and 10-20 dB attenuation of random disturbances in the frequency range of 5-200 Hz.

  6. Robust Control for Microgravity Vibration Isolation using Fixed Order, Mixed H2/Mu Design

    Science.gov (United States)

    Whorton, Mark

    2003-01-01

    Many space-science experiments need an active isolation system to provide a sufficiently quiescent microgravity environment. Modern control methods provide the potential for both high-performance and robust stability in the presence of parametric uncertainties that are characteristic of microgravity vibration isolation systems. While H2 and H(infinity) methods are well established, neither provides the levels of attenuation performance and robust stability in a compensator with low order. Mixed H2/H(infinity), controllers provide a means for maximizing robust stability for a given level of mean-square nominal performance while directly optimizing for controller order constraints. This paper demonstrates the benefit of mixed norm design from the perspective of robustness to parametric uncertainties and controller order for microgravity vibration isolation. A nominal performance metric analogous to the mu measure, for robust stability assessment is also introduced in order to define an acceptable trade space from which different control methodologies can be compared.

  7. Nonlinear damping for vibration isolation of microsystems using shear thickening fluid

    Science.gov (United States)

    Iyer, S. S.; Vedad-Ghavami, R.; Lee, H.; Liger, M.; Kavehpour, H. P.; Candler, R. N.

    2013-06-01

    This work reports the measurement and analysis of nonlinear damping of micro-scale actuators immersed in shear thickening fluids (STFs). A power-law damping term is added to the linear second-order model to account for the shear-dependent viscosity of the fluid. This nonlinear model is substantiated by measurements of oscillatory motion of a torsional microactuator. At high actuation forces, the vibration velocity amplitude saturates. The model accurately predicts the nonlinear damping characteristics of the STF using a power-law index extracted from independent rheology experiments. This result reveals the potential to use STFs as adaptive, passive dampers for vibration isolation of microelectromechanical systems.

  8. Six-degree-of-freedom active vibration isolation using a Stewart platform mechanism

    Science.gov (United States)

    Geng, Zheng; Haynes, Leonard S.

    1993-01-01

    The design and control problems of a class of multidegree-of-freedom vibration isolation systems (VISs) based on a Stewart platform mechanism are studied. A prototype of a six-degree-of-freedom VIS for precision control of a wide range of space-based structures implemented in Intelligent Automation, Inc. is described. The feasibility of using a Stewart platform to achieve 6-degree-of-freedom vibration control in space applications is shown. A new Terfenol-D actuator characterized by significantly longer stroke than any commercially available Terfenol-D actuator and direct flux and strain sensors integral to the actuator is described.

  9. Active tuned mass damper for damping of offshore wind turbine vibrations

    DEFF Research Database (Denmark)

    Brodersen, Mark Laier; Bjørke, Ann-Sofie; Høgsberg, Jan Becker

    2017-01-01

    An active tuned mass damper (ATMD) is employed for damping of tower vibrations of fixed offshore wind turbines, where the additional actuator force is controlled using feedback from the tower displacement and the relative velocity of the damper mass. An optimum tuning procedure equivalent to the ...

  10. Effect of some additives on mass transfer coefficient at a vibrating horizontal screen

    Energy Technology Data Exchange (ETDEWEB)

    Nosier, S.A.; El-Abd, M.Z. [Chemical Engineering Dept., Faculty of Engineering, Alexandria Univ. (Egypt); Zaki, M.M. [Environmental Engineering Dept., Faculty of Engineering, Zagazig Univ. (Egypt)

    1998-01-01

    The addition of small amounts of high molecular weight substances, such as polymers and surface-active agents, to fluids can produce significant reduction of friction in turbulent flow. The objectiv of the present work is to study the effect of drag-reducing additives such as Polyox WSR 301 and sodium lauryl sulfate (anionic surfactant) on the rate of mass transfer at a vibrating horizontal screen. The variables studied were the concentration of polymer and surfactant, frequency of vibration and amplitude of vibration. (orig.)

  11. THE REDUCTION OF VIBRATIONS IN A CAR – THE PRINCIPLE OF PNEUMATIC DUAL MASS FLYWHEEL

    Directory of Open Access Journals (Sweden)

    Robert GREGA

    2014-09-01

    Full Text Available The dual-mass flywheel replaces the classic flywheel in such way that it is divided into two masses (the primary mass and the secondary mass, which are jointed together by means of a flexible interconnection. This kind of the flywheel solution enables to change resonance areas of the engine with regard to the engine dynamic behaviour what leads to a reduction of vibrations consequently. However, there is also a disadvantage of the dualmass flywheels. The disadvantage is its short-time durability. There was projected a new type of the dual-mass flywheel in the framework of our workplace in order to eliminate disadvantages of the present dual-mass flywheels, i.e. we projected the pneumatic dual-mass flywheel, taking into consideration our experiences obtained during investigation of vibrations.

  12. ENIDINE: Vibration and seismic isolation technologies for power generation station applications

    International Nuclear Information System (INIS)

    Zemanek, T.A.

    1994-01-01

    ENIDINE Inc. is a world leader in the design and manufacture of shock and vibration mounts. Founded in 1966, the company has two manufacturing facilities, employs over 300 people and supports a worldwide network of distributors and representatives. ENIDINE Inc. is part of the ENIDINE Corporate Group which owns a number of companies that design and manufacture Hydraulic/Pneumatic cylinders, Electromechanical devices, Hydraulic Control Valves and a number of Industrial Distribution companies throughout Europe. In total, the ENIDINE Corporate Group has over 900 employees with annual sales of over $100 million. ENIDINE shock and vibration mounts are used to isolate the vibration of missiles from their guidance systems, pumps from hospital operating equipment and off shore oil rigs, from the shock energy of waves in the North Sea. ENIDINE products can be found on all Boeing and McDonnell Douglas aircraft, as well as many electronic and weapons systems on board Navy ships

  13. Modeling of vibrations isolation and arrest by shape memory parts and permanent magnets

    Science.gov (United States)

    Belyaev, Fedor S.; Volkov, Aleksandr E.; Evard, Margarita E.; Vikulenkov, Andrey V.; Uspenskiy, Evgeniy S.

    2018-05-01

    A vibration protection system under consideration consists of a payload connected to a vibrating housing by shape memory alloy (SMA) slotted springs. To provide an arrest function two permanent magnets are inserted into the system. The slotted SMA elements are preliminary deformed in the martensitic state. Activation of one element by heating initiates force and displacement generation, which provide an arrest of the payload by magnets. The magnets also secure the arrest mode after cooling of the SMA element. Activation of the other element results in uncaging of the payload and switching to the vibration isolation mode. Computer simulations of arrest and uncaging when the housing is quiescent or producing sine-wave displacements were carried out. Functional-mechanical behavior of SMA parts was described by means of a microstructural model.

  14. Verification of the Microgravity Active Vibration Isolation System based on Parabolic Flight

    Science.gov (United States)

    Zhang, Yong-kang; Dong, Wen-bo; Liu, Wei; Li, Zong-feng; Lv, Shi-meng; Sang, Xiao-ru; Yang, Yang

    2017-12-01

    The Microgravity active vibration isolation system (MAIS) is a device to reduce on-orbit vibration and to provide a lower gravity level for certain scientific experiments. MAIS system is made up of a stator and a floater, the stator is fixed on the spacecraft, and the floater is suspended by electromagnetic force so as to reduce the vibration from the stator. The system has 3 position sensors, 3 accelerometers, 8 Lorentz actuators, signal processing circuits and a central controller embedded in the operating software and control algorithms. For the experiments on parabolic flights, a laptop is added to MAIS for monitoring and operation, and a power module is for electric power converting. The principle of MAIS is as follows: the system samples the vibration acceleration of the floater from accelerometers, measures the displacement between stator and floater from position sensitive detectors, and computes Lorentz force current for each actuator so as to eliminate the vibration of the scientific payload, and meanwhile to avoid crashing between the stator and the floater. This is a motion control technic in 6 degrees of freedom (6-DOF) and its function could only be verified in a microgravity environment. Thanks for DLR and Novespace, we get a chance to take the DLR 27th parabolic flight campaign to make experiments to verify the 6-DOF control technic. The experiment results validate that the 6-DOF motion control technique is effective, and vibration isolation performance perfectly matches what we expected based on theoretical analysis and simulation. The MAIS has been planned on Chinese manned spacecraft for many microgravity scientific experiments, and the verification on parabolic flights is very important for its following mission. Additionally, we also test some additional function by microgravity electromagnetic suspension, such as automatic catching and locking and working in fault mode. The parabolic flight produces much useful data for these experiments.

  15. Improving of the operation efficiency of the vehicle due to using of the neodymium magnets inside the vibration isolation devices

    Science.gov (United States)

    Gurova, E. G.

    2015-09-01

    In this paper the isolation suspension with stiffness compensator based on neodymium magnets is suggested. It was found that the passive vibration isolators not completely sufficient of modern requirement of the vibration isolation. It was determined that the neodymium magnets with the same initial parameters are most effective in comparison with DC current electromagnets. The mathematical model of the vibration isolation suspension has been developed. In this research the traction characteristics for given magnets are presented. Also the design of the vibration isolation suspension with compensator of the stiffness based on neodymium magnets has been developed. This research has been performed under support of the President scholarship for young scientists under the order of Russian Federation Ministry of the education and science No 184 from 10th of March 2015.

  16. Vibration isolation/suppression: research experience for undergraduates in mechatronics and smart structures

    Science.gov (United States)

    Fonda, James; Rao, Vittal S.; Sana, Sridhar

    2001-08-01

    This paper provides an account of a student research project conducted under the sponsoring of the National Science Foundation (NSF) program on Research Experience for Undergraduates (REU) in Mechatronics and Smart Strictures in the summer of 2000. The objective of the research is to design and test a stand-alone controller for a vibration isolation/suppression system. The design specification for the control system is to suppress the vibrations induced by the external disturbances by at least fiver times and hence to achieve vibration isolation. Piezo-electric sensors and actuators are utilized for suppression of unwanted vibrations. Various steps such as modeling of the system, controller design, simulation, closed-loop testing using d- Space rapid prototyping system, and analog control implementation are discussed in the paper. Procedures for data collection, the trade-offs carried out in the design, and analog controller implementation issues are also presented in the paper. The performances of various controllers are compared. The experiences of an undergraduate student are summarized in the conclusion of the paper.

  17. The Characteristics of Vibration Isolation System with Damping and Stiffness Geometrically Nonlinear

    Science.gov (United States)

    Lu, Ze-Qi; Chen, Li-Qun; Brennan, Michael J.; Li, Jue-Ming; Ding, Hu

    2016-09-01

    The paper concerns an investigation into the use of both stiffness and damping nonlinearity in the vibration isolator to improve its effectiveness. The nonlinear damping and nonlinear stiffness are both achieved by horizontal damping and stiffness as the way of the geometrical nonlinearity. The harmonic balance method is used to analyze the force transmissibility of such vibration isolation system. It is found that as the horizontal damping increasing, the height of the force transmissibility peak is decreased and the high-frequency force transmissibility is almost the same. The results are also validated by some numerical method. Then the RMS of transmissibility under Gaussian white noise is calculated numerically, the results demonstrate that the beneficial effects of the damping nonlinearity can be achieved under random excitation.

  18. Vibration Isolation and Trajectory Following Control of a Cable Suspended Stewart Platform

    Directory of Open Access Journals (Sweden)

    Xuechao Duan

    2016-10-01

    Full Text Available To achieve high-quality vibration isolation and trajectory following control of a cable driven parallel robot based Stewart platform in the five hundred meter aperture spherical radio telescope (FAST design, the integrated dynamic model of the Stewart platform including the electric cylinder is established in this paper, the globally feedback linearization of the dynamic model is implemented based on the control law partitioning approach. To overcome the disadvantages of the external disturbance on the base and unmodeled flexibility of the mechanism, a PID (Proportional-Derivative-Integral controller with base acceleration feedforward is designed in the operational space of the Stewart platform. Experiments of the vibration isolation and trajectory following control of the cable suspended Stewart platform with presence of the base disturbance is carried out. The experimental results show that the presented control scheme has the advantage of stable dynamics, high accuracy and strong robustness.

  19. Bifurcations and chaos of a vibration isolation system with magneto-rheological damper

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hailong [Magneto-electronics Lab, School of Physics and Technology, Nanjing Normal University, Nanjing 210046 (China); Vibration Control Lab, School of Electrical and Automation Engineering, Nanjing Normal University, Nanjing 210042 (China); Zhang, Ning [Magneto-electronics Lab, School of Physics and Technology, Nanjing Normal University, Nanjing 210046 (China); Min, Fuhong; Yan, Wei; Wang, Enrong, E-mail: erwang@njnu.edu.cn [Vibration Control Lab, School of Electrical and Automation Engineering, Nanjing Normal University, Nanjing 210042 (China)

    2016-03-15

    Magneto-rheological (MR) damper possesses inherent hysteretic characteristics. We investigate the resulting nonlinear behaviors of a two degree-of-freedom (2-DoF) MR vibration isolation system under harmonic external excitation. A MR damper is identified by employing the modified Bouc-wen hysteresis model. By numerical simulation, we characterize the nonlinear dynamic evolution of period-doubling, saddle node bifurcating and inverse period-doubling using bifurcation diagrams of variations in frequency with a fixed amplitude of the harmonic excitation. The strength of chaos is determined by the Lyapunov exponent (LE) spectrum. Semi-physical experiment on the 2-DoF MR vibration isolation system is proposed. We trace the time history and phase trajectory under certain values of frequency of the harmonic excitation to verify the nonlinear dynamical evolution of period-doubling bifurcations to chaos. The largest LEs computed with the experimental data are also presented, confirming the chaotic motion in the experiment. We validate the chaotic motion caused by the hysteresis of the MR damper, and show the transitions between distinct regimes of stable motion and chaotic motion of the 2-DoF MR vibration isolation system for variations in frequency of external excitation.

  20. Bifurcations and chaos of a vibration isolation system with magneto-rheological damper

    Directory of Open Access Journals (Sweden)

    Hailong Zhang

    2016-03-01

    Full Text Available Magneto-rheological (MR damper possesses inherent hysteretic characteristics. We investigate the resulting nonlinear behaviors of a two degree-of-freedom (2-DoF MR vibration isolation system under harmonic external excitation. A MR damper is identified by employing the modified Bouc-wen hysteresis model. By numerical simulation, we characterize the nonlinear dynamic evolution of period-doubling, saddle node bifurcating and inverse period-doubling using bifurcation diagrams of variations in frequency with a fixed amplitude of the harmonic excitation. The strength of chaos is determined by the Lyapunov exponent (LE spectrum. Semi-physical experiment on the 2-DoF MR vibration isolation system is proposed. We trace the time history and phase trajectory under certain values of frequency of the harmonic excitation to verify the nonlinear dynamical evolution of period-doubling bifurcations to chaos. The largest LEs computed with the experimental data are also presented, confirming the chaotic motion in the experiment. We validate the chaotic motion caused by the hysteresis of the MR damper, and show the transitions between distinct regimes of stable motion and chaotic motion of the 2-DoF MR vibration isolation system for variations in frequency of external excitation.

  1. Vibration of nonuniform carbon nanotube with attached mass via nonlocal Timoshenko beam theory

    International Nuclear Information System (INIS)

    Tang, Hai Li; Shen, Zhi Bin; Li, Dao Kui

    2014-01-01

    This paper studies the vibrational behavior of nonuniform single-walled carbon nanotube (SWCNT) carrying a nanoparticle. A nonuniform cantilever beam with a concentrated mass at the free end is analyzed according to the nonlocal Timoshenko beam theory. A governing equation of a nonuniform SWCNT with attached mass is established. The transfer function method incorporating with the perturbation method is utilized to obtain the resonant frequencies of a vibrating nonlocal cantilever-mass system. The effects of the nonlocal parameter, taper ratio and attached mass on the natural frequencies and frequency shifts are discussed. Obtained results indicate that the sensitivity of the frequency shifts on the attached mass increases when the length-to-diameter ratio decreases. Tapered SWCNT possesses higher fundamental frequencies if the taper ratio becomes larger.

  2. Vibrational relaxation and energy transfer of matrix isolated HCl and DCl

    Energy Technology Data Exchange (ETDEWEB)

    Wiesenfeld, J.M.

    1977-12-01

    Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1 ..mu..s, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N/sub 2/ and O/sub 2/ matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data.

  3. Vibrational relaxation and energy transfer of matrix isolated HCl and DCl

    International Nuclear Information System (INIS)

    Wiesenfeld, J.M.

    1977-12-01

    Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1 μs, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N 2 and O 2 matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data

  4. Active Tuned Mass Dampers for Control of In-Plane Vibrations of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Fitzgerald, B.; Basu, Biswajit; Nielsen, Søren R.K.

    2013-01-01

    matrices. The aim of this paper is to determine whether ATMDs could be used to reduce in-plane blade vibrations in wind turbines with better performance than compared with their passive counterparts. A Euler–Lagrangian wind turbine mathematical model based on energy formulation was developed......, centrifugal, and turbulent aerodynamic loadings. Investigations show promising results for the use of ATMDs in the vibration control of wind turbine blades.......This paper investigates the use of active tuned mass dampers (ATMDs) for the mitigation of in-plane vibrations in rotating wind turbine blades. The rotating wind turbine blades with tower interaction represent time-varying dynamical systems with periodically varying mass, stiffness, and damping...

  5. Mass detection by means of the vibrating nanomechanical resonators

    Czech Academy of Sciences Publication Activity Database

    Stachiv, Ivo; Fedorchenko, Alexander I.; Chen, Y.-L.

    2012-01-01

    Roč. 100, č. 9 (2012), s. 1-3 ISSN 0003-6951 R&D Projects: GA ČR(CZ) GCP101/11/J019 Institutional research plan: CEZ:AV0Z20760514; CEZ:AV0Z10100520 Keywords : mass detection * nanomechanical based resonators * mass sensitivity Subject RIV: BI - Acoustics Impact factor: 3.794, year: 2012 http://apl.aip.org/ resource /1/applab/v100/i9/p093110_s1?isAuthorized=no

  6. Determination of vibration frequency depending on abrasive mass flow rate during abrasive water jet cutting

    Czech Academy of Sciences Publication Activity Database

    Hreha, P.; Radvanská, A.; Hloch, Sergej; Peržel, V.; Krolczyk, G.; Monková, K.

    2014-01-01

    Roč. 77, 1-4 (2014), s. 763-774 ISSN 0268-3768 Institutional support: RVO:68145535 Keywords : Abrasive water jet * Abrasive mass flow rate * Vibration Subject RIV: JQ - Machines ; Tools Impact factor: 1.458, year: 2014 http://link.springer.com/article/10.1007%2Fs00170-014-6497-9#page-1

  7. Free Vibrations of a Cantilevered SWCNT with Distributed Mass in the Presence of Nonlocal Effect

    Directory of Open Access Journals (Sweden)

    M. A. De Rosa

    2015-01-01

    Full Text Available The Hamilton principle is applied to deduce the free vibration frequencies of a cantilever single-walled carbon nanotube (SWCNT in the presence of an added mass, which can be distributed along an arbitrary part of the span. The nonlocal elasticity theory by Eringen has been employed, in order to take into account the nanoscale effects. An exact formulation leads to the equations of motion, which can be solved to give the frequencies and the corresponding vibration modes. Moreover, two approximate semianalytical methods are also illustrated, which can provide quick parametric relationships. From a more practical point of view, the problem of detecting the mass of the attached particle has been solved by calculating the relative frequency shift due to the presence of the added mass: from it, the mass value can be easily deduced. The paper ends with some numerical examples, in which the nonlocal effects are thoroughly investigated.

  8. The Nonlinear Behavior of Vibrational Conveyers with Single-Mass Crank-and-Rod Exciters

    Directory of Open Access Journals (Sweden)

    G. Füsun Alışverişçi

    2012-01-01

    Full Text Available The single-mass, crank-and-rod exciters vibrational conveyers have a trough supported on elastic stands which are rigidly fastened to the trough and a supporting frame. The trough is oscillated by a common crank drive. This vibration causes the load to move forward and upward. The moving loads jump periodically and move forward with relatively small vibration. The movement is strictly related to vibrational parameters. This is applicable in laboratory conditions in the industry which accommodate a few grams of loads, up to those that accommodate tons of loading capacity. In this study I explore the transitional behavior across resonance, during the starting of a single degree of freedom vibratory system excited by crank-and-rod. A loaded vibratory conveyor is more safe to start than an empty one. Vibrational conveyers with cubic nonlinear spring and ideal vibration exciter have been analyzed analytically for primary and secondary resonance by the Method of Multiple Scales, and numerically. The approximate analytical results obtained in this study have been compared with the numerical results and have been found to be well matched.

  9. Investigation of a bistable dual-stage vibration isolator under harmonic excitation

    International Nuclear Information System (INIS)

    Yang, Kai; Huang, Hai; Harne, R L; Wang, K W

    2014-01-01

    This study explores the steady-state performance of a dual-stage vibration isolator, which is configured by a bistable oscillator and a linear oscillator. The potential force of the bistable stage comprises negative linear and positive cubic nonlinear stiffnesses such that the two restoring force contributions may counterbalance to minimize dynamic force transmission. By applying a first-order harmonic balance, it is predicted that the bistable dual-stage isolator may significantly outperform an equivalent pure linear dual-stage isolator. This conclusion is verified through a series of numerical investigations. Following a parametric study, design guidelines are detailed to achieve performance improvements. Then, the ‘valley’ response, which is the special phenomenon of the bistable dual-stage isolator due to the counterbalance of the negative linear and positive nonlinear potential forces, is revealed and quantitatively explained. Numerical studies demonstrate the role of initial conditions, and it is shown that the likelihood of beneficial single periodic valley and intra-well responses for isolation purposes can be increased by greater bistable stage damping. Finally, a bistable dual-stage isolator prototype is developed and tested, and the numerical and experimental results verify the theoretical predictions. (paper)

  10. A free vibration of beams carrying a concentrated mass under distributed axial forces

    International Nuclear Information System (INIS)

    Nagai, Ken-ichi; Nagaya, Kosuke; Takeda, Sadahiko; Arai, Noriyuki.

    1988-01-01

    The free bending vibrations of beams with a concentrated mass subjected to axial forces caused by axial acceleration are analyzed by the Galerkin method, introducing the mode shape functions which are the sum of the products of the finite power series and the trigonometrical function. This analytical method makes it easy to construct the equations of motion in each boundary condition only by exchanging the coefficients of the finite power series. Numerical calculations are carried out under four sets of boundary conditions combined with simply supported and clamped edges. The natural frequencies and the corresponding modes of vibration are determined under both various locations of the concentrated mass and axial forces. it is found that the transverse inertia force and the axial force, due to the concentrated mass, have significant effects on the change of the natural frequencies for beams. Furthermore the distinction of boundary conditions gives predominant influence to the variation of natural frequencies. (author)

  11. Study of Bubble Size, Void Fraction, and Mass Transport in a Bubble Column under High Amplitude Vibration

    Directory of Open Access Journals (Sweden)

    Shahrouz Mohagheghian

    2018-04-01

    Full Text Available Vertical vibration is known to cause bubble breakup, clustering and retardation in gas-liquid systems. In a bubble column, vibration increases the mass transfer ratio by increasing the residence time and phase interfacial area through introducing kinetic buoyancy force (Bjerknes effect and bubble breakup. Previous studies have explored the effect of vibration frequency (f, but minimal effort has focused on the effect of amplitude (A on mass transfer intensification. Thus, the current work experimentally examines bubble size, void fraction, and mass transfer in a bubble column under relatively high amplitude vibration (1.5 mm < A <9.5 mm over a frequency range of 7.5–22.5 Hz. Results of the present work were compared with past studies. The maximum stable bubble size under vibration was scaled using Hinze theory for breakage. Results of this work indicate that vibration frequency exhibits local maxima in both mass transfer and void fraction. Moreover, an optimum amplitude that is independent of vibration frequency was found for mass transfer enhancements. Finally, this work suggests physics-based models to predict void fraction and mass transfer in a vibrating bubble column.

  12. Isolation and mass spectrometry of transcription factor complexes.

    Science.gov (United States)

    Sebastiaan Winkler, G; Lacomis, Lynne; Philip, John; Erdjument-Bromage, Hediye; Svejstrup, Jesper Q; Tempst, Paul

    2002-03-01

    Protocols are described that enable the isolation of novel proteins associated with a known protein and the subsequent identification of these proteins by mass spectrometry. We review the basics of nanosample handling and of two complementary approaches to mass analysis, and provide protocols for the entire process. The protein isolation procedure is rapid and based on two high-affinity chromatography steps. The method does not require previous knowledge of complex composition or activity and permits subsequent biochemical characterization of the isolated factor. As an example, we provide the procedures used to isolate and analyze yeast Elongator, a histone acetyltransferase complex important for transcript elongation, which led to the identification of three novel subunits.

  13. 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.

  14. Vibration isolation analysis of new design OEM damper for malaysia vehicle suspension system featuring MR fluid

    Science.gov (United States)

    Unuh, M. H.; Muhamad, P.; Norfazrina, H. M. Y.; Ismail, M. A.; Tanasta, Z.

    2018-01-01

    The applications of semi-active damper employing magnetorheological (MR) fluids keep increasing in fulfilling the demand to control undesired vibration effect. The aim of this study is to introduce the new design of damper for Malaysian vehicle model as well to evaluate its effectiveness in promoting comfort. The vibration isolation performance of the OEM damper featuring MR fluid was analysed physically under real road profile excitation experimentally. An experiment using quarter car rig suspension and LMS SCADAS Mobile was conducted to demonstrate the influence of current in controlling the characteristics of MR fluid in alter the damping behaviour under 5 cm bump impact. Subsequently, the displacement values were measured with respect to time. The new design OEM damper featuring MR fluid was validated by comparing the data with original equipment manufacturer (OEM) passive damper results under the same approach of testing. Comparison of numerical data of the new design OEM damper shown that it can reduce the excitation amplitude up to 40% compared to those obtained by OEM passive damper. Finally, the new design OEM damper featuring MR fluid has effectively isolated the disturbance from the road profile and control the output force.

  15. Vibration isolation and dual-stage actuation pointing system for space precision payloads

    Science.gov (United States)

    Kong, Yongfang; Huang, Hai

    2018-02-01

    Pointing and stability requirements for future space missions are becoming more and more stringent. This work follows the pointing control method which consists of a traditional spacecraft attitude control system and a payload active pointing loop, further proposing a vibration isolation and dual-stage actuation pointing system for space precision payloads based on a soft Stewart platform. Central to the concept is using the dual-stage actuator instead of the traditional voice coil motor single-stage actuator to improve the payload active pointing capability. Based on a specified payload, the corresponding platform was designed to be installed between the spacecraft bus and the payload. The performance of the proposed system is demonstrated by preliminary closed-loop control investigations in simulations. With the ordinary spacecraft bus, the line-of-sight pointing accuracy can be controlled to below a few milliarcseconds in tip and tilt. Meanwhile, utilizing the voice coil motor with the softening spring in parallel, which is a portion of the dual-stage actuator, the system effectively achieves low-frequency motion transmission and high-frequency vibration isolation along the other four degree-of-freedom directions.

  16. Quantitative estimation of the influence of external vibrations on the measurement error of a coriolis mass-flow meter

    NARCIS (Netherlands)

    van de Ridder, Bert; Hakvoort, Wouter; van Dijk, Johannes; Lötters, Joost Conrad; de Boer, Andries; Dimitrovova, Z.; de Almeida, J.R.

    2013-01-01

    In this paper the quantitative influence of external vibrations on the measurement value of a Coriolis Mass-Flow Meter for low flows is investigated, with the eventual goal to reduce the influence of vibrations. Model results are compared with experimental results to improve the knowledge on how

  17. Response analysis and energy transmissibility of a vibration isolation system with real-power nonlinearities under a NMPPF controller

    International Nuclear Information System (INIS)

    Huang, Dongmei; Xu, Wei; Shi, Lingling

    2016-01-01

    Highlights: • The nonlinear modified positive position feedback (NMPPF) scheme and the real-power form of restoring and damping forces are combined to improve the response performance of a vibration isolation system. • The primary resonance, dynamical stability and energy transmissibility of the real-power vibration isolation system are studied. • The sensitivity of the controller parameters on the responses has been analyzed. • In order to suppress the amplitude peak, the feedback parameters have been determined by the frequency response. • The energy transmissibility is investigated. - Abstract: In this paper, the nonlinear modified positive position feedback (NMPPF) scheme and the real-power form of restoring and damping forces are combined to improve the response performance of a vibration isolation system. Based on the method of multiple scales, the frequency response, the stability and the energy transmissibility of the real-power vibration isolation system are studied. It is found that the controlled isolation system exhibits a softening behavior for sub-linear restoring force, while it exhibits the two peak response characteristic rather than a hardening behavior for over-linear restoring force. Further, the sensitivity of the feedback parameters on the responses is discussed. The results, compared to the conventional PPF and IRC methods, show that the proposed method is significantly more effective in controlling the steady-state response, and slightly advantageous for the steady-state dynamics control. The effectiveness of this method is also verified by time domain analysis. Then, the suitable feedback and controller parameters are derived by simulation results in which the amplitude peak is suppressed and the resonance stability is maintained. Finally, the energy transmissibility of the vibration isolation system is investigated. The results show that the feedback gain can reduce the whole transmissibility level and greatly suppress vibration

  18. Analytical and experimental investigation on a multiple-mass-element pendulum impact damper for vibration mitigation

    Science.gov (United States)

    Egger, Philipp; Caracoglia, Luca

    2015-09-01

    Impact dampers are often used in the field of civil, mechanical and aerospace engineering for reducing structural vibrations. The behavior of this type of passive control device has been investigated for several decades. In this research a distributed-mass impact damper, similar to the "chain damper" used in wind engineering, has been examined and applied to the vibration reduction on a slender line-like structural element (stay-cable). This study is motivated by a practical problem and describes the derivation of a reduced-order model for explaining the behavior, observed during a field experiment on a prototype system. In its simplest form, the dynamics of the apparatus is modeled as a "resilient damper", composed of mass-spring-dashpot secondary elements, attached to the primary structure. Various sources of excitation are analyzed: free vibration, external harmonic force and random excitation. The proposed model is general and potentially applicable to the analysis of several structural systems. The study also shows that the model can adequately describe and explain the experimentally observed behavior.

  19. Dynamics of vibration isolation system with rubber-cord-pneumatic spring with damping throttle

    Science.gov (United States)

    Burian, Yu A.; Silkov, M. V.

    2017-06-01

    The study refers to the important area of applied mechanics; it is the theory of vibration isolation of vibroactive facilities. The design and the issues of mathematical modeling of pneumatic spring perspective design made on the basis of rubber-cord shell with additional volume connected with its primary volume by means of throttle passageway are considered in the text. Damping at the overflow of air through the hole limits the amplitude of oscillation at resonance. But in contrast to conventional systems with viscous damping it does not increase transmission ratio at high frequencies. The mathematical model of suspension allowing selecting options to reduce the power transmission ratio on the foundation, especially in the high frequency range is obtained

  20. A THEORETICAL STUDY AND 3D MODELING OF NONLINEAR PASSIVE VIBRATION ISOLATOR

    OpenAIRE

    Sabyasachi Mukherjee

    2017-01-01

    The study of sound and vibration are closely related. Sound or "pressure waves" are generated by vibrating structures (e.g. vocal cords); these pressure waves can also induce the vibration of structures (e.g. ear drum). Hence, when trying to reduce noise it is often a problem in trying to reduce vibration. The high speed engines and machines when mounted on foundations and supports cause vibrations of excessive amplitude because of unbalance forces setup during their working. These are the di...

  1. Vibration control of buildings by using partial floor loads as multiple tuned mass

    Directory of Open Access Journals (Sweden)

    Tharwat A. Sakr

    2017-08-01

    Full Text Available Tuned mass dampers (TMDs are considered as the most common control devices used for protecting high-rise buildings from vibrations. Because of their simplicity and efficiency, they have found wide practical applications in high-rise buildings around the world. This paper proposes an innovative technique for using partial floor loads as multiple TMDs at limited number of floors. This technique eliminates complications resulting from the addition of huge masses required for response control and maintains the mass of the original structure without any added loads. The effects of using partial loads of limited floors starting from the top as TMDs on the vibration response of buildings to wind and earthquakes are investigated. The effects of applying the proposed technique to buildings with different heights and characteristics are also investigated. A parametric study is carried out to illustrate how the behavior of a building is affected by the number of stories and the portion of the floor utilized as TMDs. Results indicate the effectiveness of the proposed control technique in enhancing the drift, acceleration, and force response of buildings to wind and earthquakes. The response of buildings to wind and earthquakes was observed to be more enhanced by increasing the story-mass ratios and the number of floor utilized as TMDs.

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

    Science.gov (United States)

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

    2018-03-01

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

  3. Magnetically tuned mass dampers for optimal vibration damping of large structures

    International Nuclear Information System (INIS)

    Bourquin, Frederic; Siegert, Dominique; Caruso, Giovanni; Peigney, Michael

    2014-01-01

    This paper deals with the theoretical and experimental analysis of magnetically tuned mass dampers, applied to the vibration damping of large structures of civil engineering interest. Two devices are analysed, for which both the frequency tuning ratio and the damping coefficient can be easily and finely calibrated. They are applied for the damping of the vibrations along two natural modes of a mock-up of a bridge under construction. An original analysis, based on the Maxwell receding image method, is developed for estimating the drag force arising inside the damping devices. It also takes into account self-inductance effects, yielding a complex nonlinear dependence of the drag force on the velocity. The analysis highlights the range of velocities for which the drag force can be assumed of viscous type, and shows its dependence on the involved geometrical parameters of the dampers. The model outcomes are then compared to the corresponding experimental calibration curves. A dynamic model of the controlled structure equipped with the two damping devices is presented, and used for the development of original optimization expressions and for determining the corresponding maximum achievable damping. Finally, several experimental results are presented, concerning both the free and harmonically forced vibration damping of the bridge mock-up, and compared to the corresponding theoretical predictions. The experimental results reveal that the maximum theoretical damping performance can be achieved, when both the tuning frequencies and damping coefficients of each device are finely calibrated according to the optimization expressions. (paper)

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

    Science.gov (United States)

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

    2018-01-01

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

  5. Modal mass estimation from ambient vibrations measurement: A method for civil buildings

    Science.gov (United States)

    Acunzo, G.; Fiorini, N.; Mori, F.; Spina, D.

    2018-01-01

    A new method for estimating the modal mass ratios of buildings from unscaled mode shapes identified from ambient vibrations is presented. The method is based on the Multi Rigid Polygons (MRP) model in which each floor of the building is ideally divided in several non-deformable polygons that move independent of each other. The whole mass of the building is concentrated in the centroid of the polygons and the experimental mode shapes are expressed in term of rigid translations and of rotations. In this way, the mass matrix of the building can be easily computed on the basis of simple information about the geometry and the materials of the structure. The modal mass ratios can be then obtained through the classical equation of structural dynamics. Ambient vibrations measurement must be performed according to this MRP models, using at least two biaxial accelerometers per polygon. After a brief illustration of the theoretical background of the method, numerical validations are presented analysing the method sensitivity for possible different source of errors. Quality indexes are defined for evaluating the approximation of the modal mass ratios obtained from a certain MRP model. The capability of the proposed model to be applied to real buildings is illustrated through two experimental applications. In the first one, a geometrically irregular reinforced concrete building is considered, using a calibrated Finite Element Model for validating the results of the method. The second application refers to a historical monumental masonry building, with a more complex geometry and with less information available. In both cases, MRP models with a different number of rigid polygons per floor are compared.

  6. Design and parametric study on energy harvesting from bridge vibration using tuned dual-mass damper systems

    Science.gov (United States)

    Takeya, Kouichi; Sasaki, Eiichi; Kobayashi, Yusuke

    2016-01-01

    A bridge vibration energy harvester has been proposed in this paper using a tuned dual-mass damper system, named hereafter Tuned Mass Generator (TMG). A linear electromagnetic transducer has been applied to harvest and make use of the unused reserve of energy the aforementioned damper system absorbs. The benefits of using dual-mass systems over single-mass systems for power generation have been clarified according to the theory of vibrations. TMG parameters have been determined considering multi-domain parameters, and TMG has been tuned using a newly proposed parameter design method. Theoretical analysis results have shown that for effective energy harvesting, it is essential that TMG has robustness against uncertainties in bridge vibrations and tuning errors, and the proposed parameter design method for TMG has demonstrated this feature.

  7. Three-Dimensional Vibration Isolator for Suppressing High-Frequency Responses for Sage III Contamination Monitoring Package (CMP)

    Science.gov (United States)

    Li, Y.; Cutright, S.; Dyke, R.; Templeton, J.; Gasbarre, J.; Novak, F.

    2015-01-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) III - International Space Station (ISS) instrument will be used to study ozone, providing global, long-term measurements of key components of the Earth's atmosphere for the continued health of Earth and its inhabitants. SAGE III is launched into orbit in an inverted configuration on SpaceX;s Falcon 9 launch vehicle. As one of its four supporting elements, a Contamination Monitoring Package (CMP) mounted to the top panel of the Interface Adapter Module (IAM) box experiences high-frequency response due to structural coupling between the two structures during the SpaceX launch. These vibrations, which were initially observed in the IAM Engineering Development Unit (EDU) test and later verified through finite element analysis (FEA) for the SpaceX launch loads, may damage the internal electronic cards and the Thermoelectric Quartz Crystal Microbalance (TQCM) sensors mounted on the CMP. Three-dimensional (3D) vibration isolators were required to be inserted between the CMP and IAM interface in order to attenuate the high frequency vibrations without resulting in any major changes to the existing system. Wire rope isolators were proposed as the isolation system between the CMP and IAM due to the low impact to design. Most 3D isolation systems are designed for compression and roll, therefore little dynamic data was available for using wire rope isolators in an inverted or tension configuration. From the isolator FEA and test results, it is shown that by using the 3D wire rope isolators, the CMP high-frequency responses have been suppressed by several orders of magnitude over a wide excitation frequency range. Consequently, the TQCM sensor responses are well below their qualification environments. It is indicated that these high-frequency responses due to the typical instrument structural coupling can be significantly suppressed by a vibration passive control using the 3D vibration isolator. Thermal and contamination

  8. Modeling and experimental verification of proof mass effects on vibration energy harvester performance

    International Nuclear Information System (INIS)

    Kim, Miso; Hoegen, Mathias; Dugundji, John; Wardle, Brian L

    2010-01-01

    An electromechanically coupled model for a cantilevered piezoelectric energy harvester with a proof mass is presented. Proof masses are essential in microscale devices to move device resonances towards optimal frequency points for harvesting. Such devices with proof masses have not been rigorously modeled previously; instead, lumped mass or concentrated point masses at arbitrary points on the beam have been used. Thus, this work focuses on the exact vibration analysis of cantilevered energy harvester devices including a tip proof mass. The model is based not only on a detailed modal analysis, but also on a thorough investigation of damping ratios that can significantly affect device performance. A model with multiple degrees of freedom is developed and then reduced to a single-mode model, yielding convenient closed-form normalized predictions of device performance. In order to verify the analytical model, experimental tests are undertaken on a macroscale, symmetric, bimorph, piezoelectric energy harvester with proof masses of different geometries. The model accurately captures all aspects of the measured response, including the location of peak-power operating points at resonance and anti-resonance, and trends such as the dependence of the maximal power harvested on the frequency. It is observed that even a small change in proof mass geometry results in a substantial change of device performance due not only to the frequency shift, but also to the effect on the strain distribution along the device length. Future work will include the optimal design of devices for various applications, and quantification of the importance of nonlinearities (structural and piezoelectric coupling) for device performance

  9. MASS MEASUREMENTS OF ISOLATED OBJECTS FROM SPACE-BASED MICROLENSING

    DEFF Research Database (Denmark)

    Zhu, Wei; Novati, S. Calchi; Gould, A.

    2016-01-01

    lies behind the same amount of dust as the Bulge red clump, we find the lens is a 45 ± 7 {M}{{J}} BD at 5.9 ± 1.0 kpc. The lens of of the second event, OGLE-2015-BLG-0763, is a 0.50 ± 0.04 {M}⊙ star at 6.9 ± 1.0 kpc. We show that the probability to definitively measure the mass of isolated microlenses...... is dramatically increased once simultaneous ground- and space-based observations are conducted....

  10. Evaluation of a Treadmill with Vibration Isolation and Stabilization (TVIS) for Use on the International Space Station

    Science.gov (United States)

    McCrory, Jean L.; Lemmon, David R.; Sommer, H. Joseph; Prout, Brian; Smith, Damon; Korth, Deborah W.; Lucero, Javier; Greenisen, Michael; Moore, Jim

    1999-01-01

    A treadmill with vibration isolation and stabilization designed for the International Space Station (ISS) was evaluated during Shuttle mission STS-81. Three crew members ran and walked on the device, which floats freely in zero gravity. For the majority of the more than 2 hours of locomotion studied, the treadmill showed peak to peak linear and angular displacements of less than 2.5 cm and 2.5 deg, respectively. Vibration transmitted to the vehicle was within the microgravity allocation limits that are defined for the ISS. Refinements to the treadmill and harness system are discussed. This approach to treadmill design offers the possibility of generating 1G-like loads on the lower extremities while preserving the microgravity environment of the ISS for structural safety and vibration free experimental conditions.

  11. Centrosome isolation and analysis by mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Jakobsen, Lis; Schrøder, Jacob Morville; Larsen, Katja M

    2013-01-01

    Centrioles are microtubule-based scaffolds that are essential for the formation of centrosomes, cilia, and flagella with important functions throughout the cell cycle, in physiology and during development. The ability to purify centriole-containing organelles on a large scale, combined with advan...... to isolate centrosomes from human cells and strategies to selectively identify and study the properties of the associated proteins using quantitative mass spectrometry-based proteomics.......Centrioles are microtubule-based scaffolds that are essential for the formation of centrosomes, cilia, and flagella with important functions throughout the cell cycle, in physiology and during development. The ability to purify centriole-containing organelles on a large scale, combined...... with advances in protein identification using mass spectrometry-based proteomics, have revealed multiple centriole-associated proteins that are conserved during evolution in eukaryotes. Despite these advances, the molecular basis for the plethora of processes coordinated by cilia and centrosomes is not fully...

  12. Measurement Model and Precision Analysis of Accelerometers for Maglev Vibration Isolation Platforms

    Directory of Open Access Journals (Sweden)

    Qianqian Wu

    2015-08-01

    Full Text Available High precision measurement of acceleration levels is required to allow active control for vibration isolation platforms. It is necessary to propose an accelerometer configuration measurement model that yields such a high measuring precision. In this paper, an accelerometer configuration to improve measurement accuracy is proposed. The corresponding calculation formulas of the angular acceleration were derived through theoretical analysis. A method is presented to minimize angular acceleration noise based on analysis of the root mean square noise of the angular acceleration. Moreover, the influence of installation position errors and accelerometer orientation errors on the calculation precision of the angular acceleration is studied. Comparisons of the output differences between the proposed configuration and the previous planar triangle configuration under the same installation errors are conducted by simulation. The simulation results show that installation errors have a relatively small impact on the calculation accuracy of the proposed configuration. To further verify the high calculation precision of the proposed configuration, experiments are carried out for both the proposed configuration and the planar triangle configuration. On the basis of the results of simulations and experiments, it can be concluded that the proposed configuration has higher angular acceleration calculation precision and can be applied to different platforms.

  13. Measurement Model and Precision Analysis of Accelerometers for Maglev Vibration Isolation Platforms.

    Science.gov (United States)

    Wu, Qianqian; Yue, Honghao; Liu, Rongqiang; Zhang, Xiaoyou; Ding, Liang; Liang, Tian; Deng, Zongquan

    2015-08-14

    High precision measurement of acceleration levels is required to allow active control for vibration isolation platforms. It is necessary to propose an accelerometer configuration measurement model that yields such a high measuring precision. In this paper, an accelerometer configuration to improve measurement accuracy is proposed. The corresponding calculation formulas of the angular acceleration were derived through theoretical analysis. A method is presented to minimize angular acceleration noise based on analysis of the root mean square noise of the angular acceleration. Moreover, the influence of installation position errors and accelerometer orientation errors on the calculation precision of the angular acceleration is studied. Comparisons of the output differences between the proposed configuration and the previous planar triangle configuration under the same installation errors are conducted by simulation. The simulation results show that installation errors have a relatively small impact on the calculation accuracy of the proposed configuration. To further verify the high calculation precision of the proposed configuration, experiments are carried out for both the proposed configuration and the planar triangle configuration. On the basis of the results of simulations and experiments, it can be concluded that the proposed configuration has higher angular acceleration calculation precision and can be applied to different platforms.

  14. Chaotification of vibration isolation floating raft system via nonlinear time-delay feedback control

    International Nuclear Information System (INIS)

    Zhang Jing; Xu Daolin; Zhou Jiaxi; Li Yingli

    2012-01-01

    Highlights: ► A chaotification method based on nonlinear time-delay feedback control is present. ► An analytical function of nonlinear time-delay feedback control is derived. ► A large range of parametric domain for chaotification is obtained. ► The approach allows using small control gain. ► Design of chaotification becomes a standard process without uncertainty. - Abstract: This paper presents a chaotification method based on nonlinear time-delay feedback control for a two-dimensional vibration isolation floating raft system (VIFRS). An analytical function of nonlinear time-delay feedback control is derived. This approach can theoretically provide a systematic design of chaotification for nonlinear VIFRS and completely avoid blind and inefficient numerical search on the basis of trials and errors. Numerical simulations show that with a proper setting of control parameters the method holds the favorable aspects including the capability of chaotifying across a large range of parametric domain, the advantage of using small control and the flexibility of designing control feedback forms. The effects on chaotification performance are discussed in association with the configuration of the control parameters.

  15. Mode shape combination in a two-dimensional vibration energy harvester through mass loading structural modification

    Energy Technology Data Exchange (ETDEWEB)

    Sharpes, Nathan; Kumar, Prashant [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Abdelkefi, Abdessattar; Abdelmoula, Hichem [Department of Mechanical and Aerospace Engineering, New Mexico State University, Las Cruces, New Mexico 88003 (United States); Adler, Jan [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Institute of Dynamics and Vibration Research (IDS), Leibniz Universität, Hannover 30167 (Germany); Priya, Shashank [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Bio-Inspired Materials and Devices Laboratory (BMDL), Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2016-07-18

    Mode shapes in the design of mechanical energy harvesters, as a means of performance increase, have been largely overlooked. Currently, the vast majority of energy harvester designs employ some variation of a single-degree-of-freedom cantilever, and the mode shapes of such beams are well known. This is especially true for the first bending mode, which is almost exclusively the chosen vibration mode for energy harvesting. Two-dimensional beam shapes (those which curve, meander, spiral, etc., in a plane) have recently gained research interest, as they offer freedom to modify the vibration characteristics of the harvester beam for achieving higher power density. In this study, the second bending mode shape of the “Elephant” two-dimensional beam shape is examined, and its interaction with the first bending mode is evaluated. A combinatory mode shape created by using mass loading structural modification to lower the second bending modal frequency was found to interact with the first bending mode. This is possible since the first two bending modes do not share common areas of displacement. The combined mode shape is shown to produce the most power of any of the considered mode shapes.

  16. Multiple tuned mass damper based vibration mitigation of offshore wind turbine considering soil-structure interaction

    Science.gov (United States)

    Hussan, Mosaruf; Sharmin, Faria; Kim, Dookie

    2017-08-01

    The dynamics of jacket supported offshore wind turbine (OWT) in earthquake environment is one of the progressing focuses in the renewable energy field. Soil-structure interaction (SSI) is a fundamental principle to analyze stability and safety of the structure. This study focuses on the performance of the multiple tuned mass damper (MTMD) in minimizing the dynamic responses of the structures objected to seismic loads combined with static wind and wave loads. Response surface methodology (RSM) has been applied to design the MTMD parameters. The analyses have been performed under two different boundary conditions: fixed base (without SSI) and flexible base (with SSI). Two vibration modes of the structure have been suppressed by multi-mode vibration control principle in both cases. The effectiveness of the MTMD in reducing the dynamic response of the structure is presented. The dynamic SSI plays an important role in the seismic behavior of the jacket supported OWT, especially resting on the soft soil deposit. Finally, it shows that excluding the SSI effect could be the reason of overestimating the MTMD performance.

  17. Effect of rotary inertia of concentrated masses on the natural vibration of fluid conveying pipes

    International Nuclear Information System (INIS)

    Kang, Myeong Gie

    1999-01-01

    Effects of the rotary inertia of concentrated masses on the natural vibrations of fluid conveying pipes have been studied by theoretical modeling and computer simulation. For analysis, two boundary conditions for pipe ends, simply supported and clamped-clamped, are assumed and Galerkin's method is used for transformation of the governing equation to the eigenvalues problem and the natural frequencies and mode shapes for the system have been calculated by using the newly developed computer code. Moreover, the critical velocities related to a system instability have been investigated. The main conclusions for the present study are (1) rotary inertia gives much change on the higher natural frequencies and mode shapes and its effect is visible when it has small value, (2) The number and location of nodes can be changed by rotary inertia, (3) By introducing rotary inertia, the second natural frequency approaches to the first as the location of the concentrated mass approaches to the midspan of the pipe, and (4) The critical fluid velocities to initiate the system unstable are unchanged by introduction of rotary inertia and the first three velocities are π, 2π, and 3π for the simply supported pipe and 2π, 8.99 and 12.57 for the clamped-clamped pipe. (author). 16 refs., 7 figs., 3 tabs

  18. Vibration mechanism's isolation installed on the compliant base (Part I: Question State)

    International Nuclear Information System (INIS)

    Djuma, R.

    2001-01-01

    The main reason of noise and vibration aggravation in houses is the considerable increase of the number of sources because of building being equipped with engineering, sanitary, technical and other mechanical equipment (lifts, pumps, ventilation, conditioner, systems and others). Very often the equipment installed on the building's coverings, is not favorable from the acoustics point of view, in comparison with equipment that is installed on separate foundation or in the basement. Vibrations that appear on the coverings in the mechanism work through the joints and transfer to the joining buildings that in their part while vibration will take the sound of the adjacent buildings. Working in the mean time normative documents on projecting of machine's vibroisolation and equipment that guide projectors and builder's, recommend to make calculations of vibroisolation on the dynamic loading that is created by working equipment only on the basic vibration frequency. (author)

  19. Vibration control of bridge subjected to multi-axle vehicle using multiple tuned mass friction dampers

    Science.gov (United States)

    Pisal, Alka Y.; Jangid, R. S.

    2016-06-01

    The effectiveness of tuned mass friction damper (TMFD) in reducing undesirable resonant response of the bridge subjected to multi-axle vehicular load is investigated. A Taiwan high-speed railway (THSR) bridge subjected to Japanese SKS (Salkesa) train load is considered. The bridge is idealized as a simply supported Euler-Bernoulli beam with uniform properties throughout the length of the bridge, and the train's vehicular load is modeled as a series of moving forces. Simplified model of vehicle, bridge and TMFD system has been considered to derive coupled differential equations of motion which is solved numerically using the Newmark's linear acceleration method. The critical train velocities at which the bridge undergoes resonant vibration are investigated. Response of the bridge is studied for three different arrangements of TMFD systems, namely, TMFD attached at mid-span of the bridge, multiple tuned mass friction dampers (MTMFD) system concentrated at mid-span of the bridge and MTMFD system with distributed TMFD units along the length of the bridge. The optimum parameters of each TMFD system are found out. It has been demonstrated that an optimized MTMFD system concentrated at mid-span of the bridge is more effective than an optimized TMFD at the same place with the same total mass and an optimized MTMFD system having TMFD units distributed along the length of the bridge. However, the distributed MTMFD system is more effective than an optimized TMFD system, provided that TMFD units of MTMFD system are distributed within certain limiting interval and the frequency of TMFD units is appropriately distributed.

  20. Integrated hybrid vibration isolator with feedforward compensation for fast high-precision positioning X/Y tables

    International Nuclear Information System (INIS)

    Yan, T H; Li, Q; Xu, C; Pu, H Y; Chen, X D

    2010-01-01

    The design, realization and control technologies of a high-performance hybrid microvibration isolator for ultra-high-precision high-speed moving X/Y tables are presented in this paper—the novel isolator with integrated passive–active high level of damping. The passive damping was implemented using air-springs in both vertical and horizontal directions, with parallel linear motors in two directions to realize the active damping and the positioning functions. It is an actual hybrid isolation system because its air-spring can also be controlled through the pneumatic loop. The isolation servo system also has fast positioning capability via the feedforward compensation for the moving tables. Compared with the conventional filtered reference type control algorithms that rely on the assumption for the adaptive filter and the controlled system, in which the disturbance is estimated from the residual signal, the feedforward compensation here shows high effectiveness of vibration isolation and high-precision positioning performance for its platform. The performance of feedforward compensation has been enhanced via an efficient state estimation adaptive algorithm, the fast Kalman filter. Finally, experimental demonstration has been shown for the prototype system and the results have verified the effectiveness of the proposed isolator system design and the adaptive control algorithm for substantially enhanced damping of the platform system with the moving X/Y tables

  1. Maximizing semi-active vibration isolation utilizing a magnetorheological damper with an inner bypass configuration

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xian-Xu, E-mail: bai@hfut.edu.cn [Department of Vehicle Engineering, Hefei University of Technology, Hefei 230009 (China); Wereley, Norman M.; Hu, Wei [Department of Aerospace Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    2015-05-07

    A single-degree-of-freedom (SDOF) semi-active vibration control system based on a magnetorheological (MR) damper with an inner bypass is investigated in this paper. The MR damper employing a pair of concentric tubes, between which the key structure, i.e., the inner bypass, is formed and MR fluids are energized, is designed to provide large dynamic range (i.e., ratio of field-on damping force to field-off damping force) and damping force range. The damping force performance of the MR damper is modeled using phenomenological model and verified by the experimental tests. In order to assess its feasibility and capability in vibration control systems, the mathematical model of a SDOF semi-active vibration control system based on the MR damper and skyhook control strategy is established. Using an MTS 244 hydraulic vibration exciter system and a dSPACE DS1103 real-time simulation system, experimental study for the SDOF semi-active vibration control system is also conducted. Simulation results are compared to experimental measurements.

  2. Application of a LIPCA for the structural vibration suppression of an aluminum cantilever beam with a tip mass

    International Nuclear Information System (INIS)

    Martua, Landong; Heo, Seok; Goo, Nam Seo

    2007-01-01

    Use of bare PZT as an actuator in the field of active vibration suppression may cause some drawbacks such as critical breaks in the installation process, short circuits in the host material and low fatigue performance. To alleviate these problems, we developed a new actuator called a lightweight piezocomposite actuator (LIPCA). The LIPCA has five layers: three glass-epoxy layers, a carbon-epoxy layer and a PZT layer. We implemented a LIPCA as an actuator to suppress the vibration of an aluminum cantilever beam with a tip mass. For the control algorithm in our test, we used positive position feedback. The filter frequency for this type of feedback should be tuned to the frequency of the target mode. The first three experimental natural frequencies of the aluminum cantilever beam agree well with the results of finite element methods. The effectiveness of using a LIPCA as an actuator in active vibration suppression was investigated with respect to the time and frequency domains, and the experimental results show that LIPCAs can significantly reduce the amplitude of forced vibrations as well as the settling time of free vibrations

  3. Stationary levitation and vibration transmission characteristic in a superconducting seismic isolation device with a permanent magnet system and a copper plate

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, S., E-mail: s.sasaki@ecei.tohoku.ac.j [Electrical Engineering Department, Graduate School, Tohoku University, 6-6-05 Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Shimada, K.; Yagai, T.; Tsuda, M.; Hamajima, T. [Electrical Engineering Department, Graduate School, Tohoku University, 6-6-05 Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Kawai, N.; Yasui, K. [Okumura Corporation, 5-6-1 Shiba, Minato-ku, Tokyo 180-8381 (Japan)

    2010-11-01

    We have devised a magnetic levitation type superconducting seismic isolation device taking advantage of the specific characteristic of HTS bulk that the HTS bulk returns to its original position by restoring force against a horizontal displacement. The superconducting seismic isolation device is composed of HTS bulks and permanent magnets (PM rails). The PMs are fixed on an iron plate to realize the same polarities in the longitudinal direction and the different polarities in the transverse direction. The superconducting seismic isolation device can theoretically remove any horizontal vibrations completely. Therefore, the vibration transmissibility in the longitudinal direction of the PM rail becomes zero in theory. The zero vibration transmissibility and the stationary levitation, however, cannot be achieved in the real device because a uniform magnetic field distribution in the longitudinal direction of PM rail cannot be realized due to the individual difference of the PMs. Therefore, to achieve stationary levitation in the real device we adopted a PM-PM system that the different polarities are faced each other. The stationary levitation could be achieved by the magnetic interaction between the PMs in the PM-PM system, while the vibration transmitted to the seismic isolation object due to the magnetic interaction. We adopted a copper plate between the PMs to reduce the vibration transmissibility. The PM-PM system with the copper plate is very useful for realizing the stationary levitation and reducing the vibration transmissibility.

  4. Stationary levitation and vibration transmission characteristic in a superconducting seismic isolation device with a permanent magnet system and a copper plate

    International Nuclear Information System (INIS)

    Sasaki, S.; Shimada, K.; Yagai, T.; Tsuda, M.; Hamajima, T.; Kawai, N.; Yasui, K.

    2010-01-01

    We have devised a magnetic levitation type superconducting seismic isolation device taking advantage of the specific characteristic of HTS bulk that the HTS bulk returns to its original position by restoring force against a horizontal displacement. The superconducting seismic isolation device is composed of HTS bulks and permanent magnets (PM rails). The PMs are fixed on an iron plate to realize the same polarities in the longitudinal direction and the different polarities in the transverse direction. The superconducting seismic isolation device can theoretically remove any horizontal vibrations completely. Therefore, the vibration transmissibility in the longitudinal direction of the PM rail becomes zero in theory. The zero vibration transmissibility and the stationary levitation, however, cannot be achieved in the real device because a uniform magnetic field distribution in the longitudinal direction of PM rail cannot be realized due to the individual difference of the PMs. Therefore, to achieve stationary levitation in the real device we adopted a PM-PM system that the different polarities are faced each other. The stationary levitation could be achieved by the magnetic interaction between the PMs in the PM-PM system, while the vibration transmitted to the seismic isolation object due to the magnetic interaction. We adopted a copper plate between the PMs to reduce the vibration transmissibility. The PM-PM system with the copper plate is very useful for realizing the stationary levitation and reducing the vibration transmissibility.

  5. Free vibration analysis of a robotic fish based on a continuous and non-uniform flexible backbone with distributed masses

    Science.gov (United States)

    Coral, W.; Rossi, C.; Curet, O. M.

    2015-12-01

    This paper presents a Differential Quadrature Element Method for free transverse vibration of a robotic fish based on a continuous and non-uniform flexible backbone with distributed masses (fish ribs). The proposed method is based on the theory of a Timoshenko cantilever beam. The effects of the masses (number, magnitude and position) on the value of natural frequencies are investigated. Governing equations, compatibility and boundary conditions are formulated according to the Differential Quadrature rules. The convergence, efficiency and accuracy are compared to other analytical solution proposed in the literature. Moreover, the proposed method has been validate against the physical prototype of a flexible fish backbone. The main advantages of this method, compared to the exact solutions available in the literature are twofold: first, smaller computational cost and second, it allows analysing the free vibration in beams whose section is an arbitrary function, which is normally difficult or even impossible with other analytical methods.

  6. Vibration analysis of carbon nanotubes-based zeptogram masses sensors and taking into account their rotatory inertia

    Directory of Open Access Journals (Sweden)

    Azrar A.

    2018-01-01

    Full Text Available In this research work, the transverse vibration behaviour of single-walled carbon nanotubes (SCNT based mass sensors is studied using the Timoshenko beam and nonlocal elasticity theories. The nonlocal constitutive equations are used in the formulations and the CNT with different lengths, attached mass (viruses and bacteria and the general boundary conditions are considered. The dimensionless frequencies and associated modes are obtained for one and two attached masses and different boundary conditions. The effects of transverse shear deformation and rotatory inertia, nonlocal parameter, length of the carbon nanotubes, and attached mass and its location are investigated in detail for each considered problem. The relationship between the frequencies and mode shapes of the sensor and the attached zeptogramme masses are obtained. The sensing devices for biological objects including viruses and bacteria can be elaborated based on the developed sensitivity and frequency shift methodological approach.

  7. Negative masses, even if isolated, imply self-acceleration, hence a catastrophic world

    International Nuclear Information System (INIS)

    Cavalleri, G.; Tonni, E.

    1997-01-01

    The conjecture of the existence of negative masses together with ordinary positive masses leads to runaway motions even if no self-reaction is considered. Pollard and Dunning-Davies have shown other constraints as a modification of the principle of least action and that negative masses can only exist at negative temperature, and must be adiabatically separate from positive masses. They show here that the self-reaction on a single isolated negative mass implies a runaway motion. Consequently, the consideration of self-fields and relevant self-reaction excludes negative masses even if isolated

  8. Integrated Vibration and Acceleration Testing to Reduce Payload Mass, Cost and Mission Risk, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a capability to provide integrated acceleration, vibration, and shock testing using a state-of-the-art centrifuge, allowing for the test of...

  9. The Shock and Vibration Bulletin. Part 4. Prediction and Experimental Techniques, Isolation and Damping

    Science.gov (United States)

    1973-06-01

    D. 0. Smallwood , Sandia Laboratories, Albuquerque, New Mexico and A. F. Witte, Kaman Sciences, Colorado Springs, Colorado fi TRANSIENT VIBRATION...TEST TECHNIQUE USING LEAST FAVORABLE RESPONSES D. O. Smallwood , Sandia Laboratories, Albuquerque, New Mexico PAPERS APPEARING IN PART 2 Structural...Dynamic Systems, Measure- ments and Control, March 1971. 12. Favour, John D., Maclom C. Mitchell, and Norman L. Olson, "Transient Test Techniques for

  10. Bi-directional vibration control of offshore wind turbines using a 3D pendulum tuned mass damper

    Science.gov (United States)

    Sun, C.; Jahangiri, V.

    2018-05-01

    Offshore wind turbines suffer from excessive bi-directional vibrations due to wind-wave misalignment and vortex induced vibrations. However, most of existing research focus on unidirectional vibration attenuation which is inadequate for real applications. The present paper proposes a three dimensional pendulum tuned mass damper (3d-PTMD) to mitigate the tower and nacelle dynamic response in the fore-aft and side-side directions. An analytical model of the wind turbine coupled with the 3d-PTMD is established wherein the interaction between the blades, the tower and the 3d-PTMD is modeled. Aerodynamic loading is computed using the Blade Element Momentum method where the Prandtls tip loss factor and the Glauert correction are considered. JONSWAP spectrum is adopted to generate wave data. Wave loading is computed using Morisons equation in collaboration with the strip theory. Via a numerical search approach, the design formula of the 3d-PTMD is obtained and examined on a National Renewable Energy Lab (NREL) monopile 5 MW baseline wind turbine model under misaligned wind, wave and seismic loading. Dual linear tuned mass dampers (TMDs) deployed in the fore-aft and side-side directions are utilized for comparison. It is found that the 3d-PTMD with a mass ratio of 2 % can improve the mitigation of the root mean square and peak response by around 10 % when compared with the dual linear TMDs in controlling the bi-directional vibration of the offshore wind turbines under misaligned wind, wave and seismic loading.

  11. Vibration Isolation Study in Scanning Probe Microscopy Part I: Low Frequency

    International Nuclear Information System (INIS)

    Oliva, A.I.; Espinosa-Faller, F.J.; Aguilar, M.

    1998-01-01

    A study of a low frequency isolation device based in a pneumatic system is presented. It consists of four cylinders which are closed and sealed with an elastic membrane on which the load is applied. Each cylinder made of PVC is formed by two chambers divided by a plate with a small hole for communication and damping. Air contained into chambers acts, in combination with the the elastic membranes, as a damper. Scanning probe techniques can be supported by this device in order to reduce the low frequency noises that affects them. Advantages of this isolator are discussed and compared. A theoretical approximation for this model is presented and compared with the experimental results obtained and show that it can isolate noises up to ∼ 2 Hz. The low frequency isolator has stability and fast response to external perturbations. This simple and economical low frequency isolator can be reproduced easily and its design depends on the work specific requirements. (Author) 9 refs

  12. Solar and interplanetary activities of isolated and non-isolated coronal mass ejections

    Science.gov (United States)

    Bendict Lawrance, M.; Shanmugaraju, A.; Moon, Y.-J.; Umapathy, S.

    2017-07-01

    We report our results on comparison of two halo Coronal Mass Ejections (CME) associated with X-class flares of similar strength (X1.4) but quite different in CME speed and acceleration, similar geo-effectiveness but quite different in Solar Energetic Particle (SEP) intensity. CME1 (non-isolated) was associated with a double event in X-ray flare and it was preceded by another fast halo CME of speed = 2684 km/s (pre-CME) associated with X-ray flare class X5.4 by 1 h from the same location. Since this pre-CME was more eastern, interaction with CME1 and hitting the earth were not possible. This event (CME1) has not suffered the cannibalism since pre-CME has faster speed than post-CME. Pre-CME plays a very important role in increasing the intensity of SEP and Forbush Decrease (FD) by providing energetic seed particles. So, the seed population is the major difference between these two selected events. CME2 (isolated) was a single event. We would like to address on the kinds of physical conditions related to such CMEs and their associated activities. Their associated activities such as, type II bursts, SEP, geomagnetic storm and FD are compared. The following results are obtained from the analysis. (1) The CME leading edge height at the start of metric/DH type II bursts are 2 R⊙/ 4 R⊙ for CME1, but 2 R⊙/ 2.75 R⊙ for CME2. (2) Peak intensity of SEP event associated with the two CMEs are quite different: 6530 pfu for CME1, but 96 pfu for CME2. (3) The Forbush decrease occurred with a minimum decrease of 9.98% in magnitude for CME1, but 6.90% for CME2. (4) These two events produced similar intense geomagnetic storms of intensity of Dst index -130 nT. (5) The maximum southward magnetic fields corresponding to Interplanetary CME (ICME) of these two events are nearly the same, but there is difference in Sheath Bz maximum (-14.2, -6.9 nT). (6) The time-line chart of the associated activities of two CMEs show some difference in the time delay between the onsets of

  13. Effects of Eight Months of Whole-Body Vibration Training on the Muscle Mass and Functional Capacity of Elderly Women.

    Science.gov (United States)

    Santin-Medeiros, Fernanda; Rey-López, Juan P; Santos-Lozano, Alejandro; Cristi-Montero, Carlos S; Garatachea Vallejo, Nuria

    2015-07-01

    Few intervention studies have used whole-body vibration (WBV) training in the elderly, and there is inconclusive evidence about its health benefits. We examined the effect of 8 months of WBV training on muscle mass and functional capacity in elderly women. A total of 37 women (aged 82.4 ± 5.7 years) voluntarily participated in this study. Subjects were randomly assigned to a vibration group (n = 19) or a control group (n = 18). The vibration group trained on a vertical vibration platform twice a week. The control group was requested not to change their habitual lifestyle. The quadriceps femoris muscle cross-sectional area was determined by magnetic resonance imaging. All participants were evaluated by a battery of tests (Senior Fitness Test) to determine their functional capacity, as well as handgrip strength and balance/gait. General linear repeated-measure analysis of variance (group by time) was performed to examine the effect of the intervention on the outcomes variables. After 8 months, nonstatistically significant differences in the quadriceps CSA (pre-training: 8,516.16 ± 1,271.78 mm² and post-training: 8,671.63 ± 1,389.03 mm²) (p > 0.05) were found in the WBV group (Cohen's d: -0.12), whereas the CON group significantly decreased muscle mass (pre-training: 9,756.18 ± 1,420.07 mm² and post-training: 9,326.82 ± 1,577.53 mm²), with moderate effect size evident (Cohen's d: 0.29). In both groups, no changes were observed in the functional capacity, handgrip strength and balance/gait. The WBV training could prevent the loss of quadriceps CSA in elderly women.

  14. Preparing isolated vibrational wave packets with light-induced molecular potentials by chirped laser pulses

    Science.gov (United States)

    Vatasescu, Mihaela

    2012-05-01

    We consider a specific wave packet preparation arising from the control of tunneling in the 0g-(6s,6p3/2) double well potential of a Cs2 cold molecule with chirped laser pulses. Such a possibility to manipulate the population dynamics in the 0g-(6s,6p3/2) potential appears in a pump-dump scheme designed to form cold molecules by photoassociation of two cold cesium atoms. The initial population in the 0g-(6s,6p3/2) double well is a wave packet prepared in the outer well at large interatomic distances (94 a0) by a photoassociation step with a first chirped pulse, being a superposition of several vibrational states whose energies surround the energy of a tunneling resonance. Our present work is focused on a second delayed chirped pulse, coupling the 0g-(6s,6p3/2) surface with the a3Σu+(6s,6s) one in the zone of the double well barrier (15 a0) and creating deeply bound cold molecules in the a3Σu+(6s,6s) state. We explore the parameters choice (intensity, duration, chirp rate and sign) for this second pulse, showing that picoseconds pulses with a negative chirp can lead to trapping of population in the inner well in strongly bound vibrational states, out of the resonant tunneling able to transfer it back to the outer well.

  15. Vibrational modes of isolated substitution impurities in twelve compounds AN B8-N with the blende structure

    International Nuclear Information System (INIS)

    Plumelle, Pierre

    1979-01-01

    We have studied a particular point defect, the isolated substitution in twelve compounds CuCl, CuBr, CuI, ZnTe, CdTe, ZnS, ZnSe, GaAs, GaP, InSb, InP and GaSb. The model of the perfect lattice is a rigid ion model with eleven parameters. Infrared localized vibrational modes of impurities are observed in a series of samples. By comparison of these experimental results with the calculated values it is possible to determine the perturbation for each particular case. A relation obtained between a force constant of the perfect crystal and the force constant of the impurity suggests that no change is introduced by the isoelectronic impurities. (author) [fr

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

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard

    2003-01-01

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

  17. Vibrational relaxation of matrix-isolated CH3F and HCl

    International Nuclear Information System (INIS)

    Young, L.

    1981-08-01

    Kinetic and spectroscopic studies have been performed on CH 3 F and HCl as a function of host matrix and temperature. Temporally and spectrally resolved infrared fluorescence was used to monitor the populations of both the initially excited state and the lower lying levels which participate in the relaxation process. For CH 3 F, relaxation from any of the levels near 3.5 μ, i.e. the CH stretching fundamentals or bend overtones, occurs via rapid ( 3 with subsequent relaxation of the ν 3 (CF stretch) manifold. Lifetimes of 2ν 3 and ν 3 were determined through overtone, ΔV = 2, and fundamental fluorescence. These lifetimes show a dramatic dependence on host lattice, an increase of two orders of magnitude in going from Xe and Ar matrices. Lifetimes depend only weakly on temperature. The relaxation of 2ν 3 and ν 3 is consistent with a model in which production of a highly rotationally excited guest via collisions with the repulsive wall of the host is the rate limiting step. For HCl, lifetimes of v = 1,2,3 have been determined. In all hosts, the relaxation is non-radiative. For a given vibrational state, v, the relaxation rate increases in the series k(Ar) < k(Kr) < k(Xe). The dependence of the relaxation rate; on v is superlinear in all matrices, the deviation from linearity increasng in the order Ar < Kr < Xe. The relaxation rates become more strongly temperature dependent with increasing vibrational excitation. The results are consistent with a mechanism in which complex formation introduces the anisotropy necessary to induce a near resonant V → R transition in the rate limiting step

  18. Evaluating performance of multivariable vibration isolators : a frequency domain identification approach applied to an industrial AVIS : A frequency domain identification approach applied to an industrial AVIS

    NARCIS (Netherlands)

    Beijen, M.A.; Heertjes, M.A.; Voorhoeve, R.J.; Oomen, T.A.E.

    2017-01-01

    Vibration isolation is essential for industrial high-precision systems in suppressing the influence of external disturbances. The aim of this paper is to develop an identification method to estimate the transmissibility matrix for such systems. The transmissibility matrix is a key performance

  19. Micro-vibration response of a stochastically excited sandwich beam with a magnetorheological elastomer core and mass

    International Nuclear Information System (INIS)

    Ying, Z G; Ni, Y Q

    2009-01-01

    Magnetorheological (MR) elastomers are used to construct a smart sandwich beam for micro-vibration control. The micro-vibration response of a clamped–free sandwich beam with an MR elastomer core and a supplemental mass under stochastic support micro-motion excitation is studied. The dynamic behavior of MR elastomer as a smart viscoelastic material is described by a complex modulus which is controllable by external magnetic field. The sixth-order partial differential equation of motion of the sandwich beam is derived from the dynamic equilibrium, constitutive and geometric relations. A frequency-domain solution method for the stochastic micro-vibration response of the sandwich beam is developed by using the frequency-response function, power spectral density function and spatial eigensolution. The root-mean-square velocity response in terms of the one-third octave frequency band is calculated, and then the response reduction capacity through optimizing the complex modulus of the core is analyzed. Numerical results illustrate the influences of the MR elastomer core parameters on the root-mean-square velocity response and the high response reduction capacity of the sandwich beam. The developed analysis method is applicable to sandwich beams with arbitrary cores described by complex shear moduli under arbitrary stochastic excitations described by power spectral density functions

  20. 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...

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

    CSIR Research Space (South Africa)

    Shatalov, M

    2009-05-01

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

  2. Control of input delayed pneumatic vibration isolation table using adaptive fuzzy sliding mode

    Directory of Open Access Journals (Sweden)

    Mostafa Khazaee

    Full Text Available AbstractPneumatic isolators are promising candidates for increasing the quality of accurate instruments. For this purpose, higher performance of such isolators is a prerequisite. In particular, the time-delay due to the air transmission is an inherent issue with pneumatic systems, which needs to be overcome using modern control methods. In this paper an adaptive fuzzy sliding mode controller is proposed to improve the performance of a pneumatic isolator in the low frequency range, i.e., where the passive techniques have obvious shortcomings. The main idea is to combine the adaptive fuzzy controller with adaptive predictor as a new time delay control technique. The adaptive fuzzy sliding mode control and the adaptive fuzzy predictor help to circumvent the input delay and nonlinearities in such isolators. The main advantage of the proposed method is that the closed-loop system stability is guaranteed under certain conditions. Simulation results reveal the effectiveness of the proposed method, compared with other existing time -delay control methods.

  3. Profiling of volatile organic compounds produced by clinical Aspergillus isolates using gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    Gerritsen, M G; Brinkman, P; Escobar Salazar, Natalia; Bos, L D; de Heer, K; Meijer, M; Janssen, H-G; de Cock, H; Wösten, H A B; Visser, C.E.; van Oers, M H J; Sterk, P J

    Volatile organic compounds (VOCs) in exhaled breath may identify the presence of invasive pulmonary aspergillosis. We aimed to detect VOC profiles emitted by in vitro cultured, clinical Aspergillus isolates using gas chromatography-mass spectrometry (GC-MS). Three clinical Aspergillus isolates and a

  4. Profiling of volatile organic compounds produced by clinical Aspergillus isolates using gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    Gerritsen, M. G.; Brinkman, P.; Escobar, N.; Bos, L. D.; de Heer, K.; Meijer, M.; Janssen, H.-G.; de Cock, H.; Wösten, H. A. B.; Visser, C. E.; van Oers, M. H. J.; Sterk, P. J.

    2018-01-01

    Volatile organic compounds (VOCs) in exhaled breath may identify the presence of invasive pulmonary aspergillosis. We aimed to detect VOC profiles emitted by in vitro cultured, clinical Aspergillus isolates using gas chromatography-mass spectrometry (GC-MS). Three clinical Aspergillus isolates and a

  5. Testing a simple control law to reduce broadband frequency harmonic vibrations using semi-active tuned mass dampers

    International Nuclear Information System (INIS)

    Moutinho, Carlos

    2015-01-01

    This paper is focused on the control problems related to semi-active tuned mass dampers (TMDs) used to reduce harmonic vibrations, specially involving civil structures. A simplified version of the phase control law is derived and its effectiveness is investigated and evaluated. The objective is to improve the functioning of control systems of this type by simplifying the measurement process and reducing the number of variables involved, making the control system more feasible and reliable. Because the control law is of ON/OFF type, combined with appropriate trigger conditions, the activity of the actuation system may be significantly reduced, which may be of few seconds a day in many practical cases, increasing the durability of the device and reducing its maintenance. Moreover, due to the ability of the control system to command the motion of the inertial mass, the semi-active TMD is relatively insensitive to its initial tuning, resulting in the capability of self-tuning and in the possibility of controlling several vibration modes of a structure over a significant broadband frequency. (paper)

  6. Bandwidth Widening of Piezoelectric Cantilever Beam Arrays by Mass-Tip Tuning for Low-Frequency Vibration Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Eduard Dechant

    2017-12-01

    Full Text Available Wireless sensor networks usually rely on internal permanent or rechargeable batteries as a power supply, causing high maintenance efforts. An alternative solution is to supply the entire system by harvesting the ambient energy, for example, by transducing ambient vibrations into electric energy by virtue of the piezoelectric effect. The purpose of this paper is to present a simple engineering approach for the bandwidth optimization of vibration energy harvesting systems comprising multiple piezoelectric cantilevers (PECs. The frequency tuning of a particular cantilever is achieved by changing the tip mass. It is shown that the bandwidth enhancement by mass tuning is limited and requires several PECs with close resonance frequencies. At a fixed frequency detuning between subsequent PECs, the achievable bandwidth shows a saturation behavior as a function of the number of cantilevers used. Since the resonance frequency of each PEC is different, the output voltages at a particular excitation frequency have different amplitudes and phases. A simple power-transfer circuit where several PECs with an individual full wave bridge rectifier are connected in parallel allows one to extract the electrical power close to the theoretical maximum excluding the diode losses. The experiments performed on two- and three-PEC arrays show reasonable agreement with simulations and demonstrate that this power-transfer circuit additionally influences the frequency dependence of the harvested electrical power.

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

    International Nuclear Information System (INIS)

    Kohgo, Osamu; Hara, Fumio

    1985-01-01

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

  8. Specific issues and proposals in aseismic design technologies (seismic isolation technologies)

    International Nuclear Information System (INIS)

    Fujita, Satoshi

    2000-01-01

    It is examined among engineers to control vibration of buildings and constructions formed by earthquake, and at present various vibration control techniques are in actual use. A vibration isolating structure passing through earthquake, and vibration controlling due to wind are its typical ones, which have been recently and rapidly supplied to actual use through a chance that laminated rubber was researched and developed for a vibration isolation supporting materials capable of supplying to actual use about 15 years ago. However, the active addition mass type vibration controller is not adequate to large earthquake countermeasure from points of addition mass size, drive variation, and limit of control power. For a vibration controller suitable for this aim an energy absorber (damper) of a type set between layers of constructions at present is the most predominant, of which various types are earnestly under research and development. Here were explained on earthquake and its energy, seismic resistant design, vibration isolation structure, and so forth. (G.K.)

  9. Effect of whole-body vibration on center-of-mass movement during standing in children and young adults.

    Science.gov (United States)

    Liang, Huaqing; Beerse, Matthew; Ke, Xiang; Wu, Jianhua

    2017-05-01

    Whole body vibration (WBV) can affect postural control and muscular activation. The purpose of this study was to investigate the center-of-mass (COM) movement of children and young adults before, during, immediately after, and 5min after 40-s WBV in quiet standing. Fourteen young adults (mean age 24.5 years) and fourteen children (mean age 8.1 years) participated in the study. A full-body 35-marker set was placed on the participants and used to calculate COM. Forty-second standing trials were collected before, during, immediately after, and 5min after WBV with an frequency of 28Hz and an amplitude of range, sway area and fractal dimension), frequency-domain measures (total power and median frequency), and detrended fluctuation analysis (DFA) scaling exponent in both anterior-posterior (AP) and medial-lateral (ML) directions. Results show that during WBV both children and adults increased average velocity and median frequency, but decreased range and the DFA scaling exponent. Immediately after WBV both groups increased the range, but showed pre-vibration values for most of the COM variables. Comparing to adults, children displayed a higher COM velocity, range, fractal dimension, and total power, but a lower DFA scaling exponent at all phases. The results suggest that both children and adults can quickly adapt their postural control system to WBV and maintain balance during and after vibration. Children display some adult-like postural control during and after WBV; however, their postural development continues into adolescence. Published by Elsevier B.V.

  10. Portable vibration-assisted filtration device for on-site isolation of blood cells or pathogenic bacteria from whole human blood.

    Science.gov (United States)

    Kim, Yong Tae; Park, Kyun Joo; Kim, Seyl; Kim, Soon Ae; Lee, Seok Jae; Kim, Do Hyun; Lee, Tae Jae; Lee, Kyoung G

    2018-03-01

    Isolation of specific cells from whole blood is important to monitor disease prognosis and diagnosis. In this study, a vibration-assisted filtration (VF) device has been developed for isolation and recovery of specific cells such as leukocytes and pathogenic bacteria from human whole blood. The VF device is composed of three layers which was fabricated using injection molding with cyclic olefin copolymer (COC) pellets consisting of: a top layer with coin-type vibration motor (Ф = 10mm), a middle plate with a 1μm or 3μm-pore filter membrane to separate of Staphylococcus aureus (S. aureus) cells or leukocytes (i.e. white blood cells) respectively, and a bottom chamber with conical-shaped microstructure. One milliliter of human whole blood was injected into a sample loading chamber using a 3μm-pore filter equipped in the VF device and the coin-type vibration motor applied external vibration force by generating a rotational fluid which enhances the filtration velocity due to the prevention of the cell clogging on the filter membrane. The effluent blood such as erythrocytes, platelet, and plasma was collected at the bottom chamber while the leukocytes were sieved by the filter membrane. The vibration-assisted leukocyte separation was able to finish within 200s while leukocyte separation took 1200s without vibration. Moreover, we successfully separated S. aureus from human whole blood using a 1μm-pore filter equipped VF device and it was further confirmed by genetic analysis. The proposed VF device provides an advanced cell separation platform in terms of simplicity, fast separation, and portability in the fields of point-of-care diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Pebble-isolation mass: Scaling law and implications for the formation of super-Earths and gas giants

    Science.gov (United States)

    Bitsch, Bertram; Morbidelli, Alessandro; Johansen, Anders; Lega, Elena; Lambrechts, Michiel; Crida, Aurélien

    2018-04-01

    The growth of a planetary core by pebble accretion stops at the so-called pebble isolation mass, when the core generates a pressure bump that traps drifting pebbles outside its orbit. The value of the pebble isolation mass is crucial in determining the final planet mass. If the isolation mass is very low, gas accretion is protracted and the planet remains at a few Earth masses with a mainly solid composition. For higher values of the pebble isolation mass, the planet might be able to accrete gas from the protoplanetary disc and grow into a gas giant. Previous works have determined a scaling of the pebble isolation mass with cube of the disc aspect ratio. Here, we expand on previous measurements and explore the dependency of the pebble isolation mass on all relevant parameters of the protoplanetary disc. We use 3D hydrodynamical simulations to measure the pebble isolation mass and derive a simple scaling law that captures the dependence on the local disc structure and the turbulent viscosity parameter α. We find that small pebbles, coupled to the gas, with Stokes number τf gap at pebble isolation mass. However, as the planetary mass increases, particles must be decreasingly smaller to penetrate the pressure bump. Turbulent diffusion of particles, however, can lead to an increase of the pebble isolation mass by a factor of two, depending on the strength of the background viscosity and on the pebble size. We finally explore the implications of the new scaling law of the pebble isolation mass on the formation of planetary systems by numerically integrating the growth and migration pathways of planets in evolving protoplanetary discs. Compared to models neglecting the dependence of the pebble isolation mass on the α-viscosity, our models including this effect result in higher core masses for giant planets. These higher core masses are more similar to the core masses of the giant planets in the solar system.

  12. Study of wind-induced vibrations in tall buildings with tuned mass dampers taking into account vortices effects

    Science.gov (United States)

    Momtaz, Ali Ajilian; Abdollahian, Mohamadreza Akhavan; Farshidianfar, Anooshiravan

    2017-12-01

    In recent years, construction of tall buildings has been of great interest. Use of lightweight materials in such structures reduces stiffness and damping, making the building more influenced by wind loads. Moreover, tall buildings of more than 30 to 40 stories, depending on the geographical location, the wind effects are more influential than earthquakes. In addition, the complexity of the effects of wind flow on the structure due to the interaction of the fluid flow and solid body results in serious damages to the structure by eliminating them. Considering the importance of the issue, the present study investigates the phenomenon of wind-induced vibration on high-rise buildings, taking into account the effects of vortices created by the fluid flow and the control of this phenomenon. To this end, the governing equations of the structure, the fluid flow and the tuned mass damper (TMD) are first introduced, and their coefficient values are extracted according to the characteristics of ACT skyscraper in Japan. Then, these three coupled equations are solved using a program coded in MATLAB. After validation of the results, the effects of wind loads are analyzed and considered with regard to the effects of vortices and the use of TMD, and are compared with the results of the state where no vortices are considered. Generally, the results of this study point out the significance of vibrations caused by vortices in construction of engineering structures as well as the appropriate performance of a TMD in reducing oscillations in tall buildings.

  13. Ultrafast Desorption by Impulsive Vibrational Excitation (DIVE). Applications in laser surgery, mass spectrometry and towards ultimate limits in biodiagnosis

    International Nuclear Information System (INIS)

    Ren, Ling

    2015-07-01

    The prospects for minimally invasive surgery, spatial imaging with mass spectrometry and rapid high throughput biodiagnosis require new means of tissue incision and biomolecule extraction with conserved molecular structure. Towards this aim, a laser ablation process is utilized in this dissertation, which is capable of performing precise tissue incision with minimal collateral damage and extracting intact biological entities with conserved biological functions. The method is based on the recently developed Picosecond Infrared Laser (PIRL) designed to excite selectively the water vibrational modes under the condition of ultrafast Desorption by Impulsive Vibrational Excitation (DIVE). The basic concept is that the selectively excited water molecules act as propellant to ablate whole biological complexes into the plume, faster than any thermal deleterious effect or fragmentation that would mask molecular identities.The PIRL ablation under DIVE condition is applied for the first time to six types of ocular tissues, rendering precise and minimally invasive incisions in a well-controlled and reproducible way. An eminent demonstration is the contact-free and applanation-free corneal trephination with the PIRL. Mass spectrometry and other analytical techniques show that great abundance of proteins with various molecular weights are extracted from the tissue by the PIRL ablation, and that fragmentation or other chemical alternation does not occur to the proteins in the ablation plume. With various microscope imaging and biochemical analysis methods, nano-scale single protein molecules, viruses and cells in the ablation plume are found to be morphologically and functionally identical to their corresponding controls. The PIRL ablation provides a new means to push the frontiers of laser surgery in ophthalmology and can be applied to resolve chemical activities in situ and in vivo. The most important finding is the conserved nature of the extracted biological entities

  14. Ultrafast Desorption by Impulsive Vibrational Excitation (DIVE). Applications in laser surgery, mass spectrometry and towards ultimate limits in biodiagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Ling

    2015-07-15

    The prospects for minimally invasive surgery, spatial imaging with mass spectrometry and rapid high throughput biodiagnosis require new means of tissue incision and biomolecule extraction with conserved molecular structure. Towards this aim, a laser ablation process is utilized in this dissertation, which is capable of performing precise tissue incision with minimal collateral damage and extracting intact biological entities with conserved biological functions. The method is based on the recently developed Picosecond Infrared Laser (PIRL) designed to excite selectively the water vibrational modes under the condition of ultrafast Desorption by Impulsive Vibrational Excitation (DIVE). The basic concept is that the selectively excited water molecules act as propellant to ablate whole biological complexes into the plume, faster than any thermal deleterious effect or fragmentation that would mask molecular identities.The PIRL ablation under DIVE condition is applied for the first time to six types of ocular tissues, rendering precise and minimally invasive incisions in a well-controlled and reproducible way. An eminent demonstration is the contact-free and applanation-free corneal trephination with the PIRL. Mass spectrometry and other analytical techniques show that great abundance of proteins with various molecular weights are extracted from the tissue by the PIRL ablation, and that fragmentation or other chemical alternation does not occur to the proteins in the ablation plume. With various microscope imaging and biochemical analysis methods, nano-scale single protein molecules, viruses and cells in the ablation plume are found to be morphologically and functionally identical to their corresponding controls. The PIRL ablation provides a new means to push the frontiers of laser surgery in ophthalmology and can be applied to resolve chemical activities in situ and in vivo. The most important finding is the conserved nature of the extracted biological entities

  15. Mathematical Models for the Apparent Mass of the Seated Human Body Exposed to Vertical Vibration

    Science.gov (United States)

    Wei, L.; Griffin, M. J.

    1998-05-01

    Alternative mathematical models of the vertical apparent mass of the seated human body are developed. The optimum parameters of four models (two single-degree-of-freedom models and two two-degree-of-freedom models) are derived from the mean measured apparent masses of 60 subjects (24 men, 24 women, 12 children) previously reported. The best fits were obtained by fitting the phase data with single-degree-of-freedom and two-degree-of-freedom models having rigid support structures. For these two models, curve fitting was performed on each of the 60 subjects (so as to obtain optimum model parameters for each subject), for the averages of each of the three groups of subjects, and for the entire group of subjects. The values obtained are tabulated. Use of a two-degree-of-freedom model provided a better fit to the phase of the apparent mass at frequencies greater than about 8 Hz and an improved fit to the modulus of the apparent mass at frequencies around 5 Hz. It is concluded that the two-degree-of-freedom model provides an apparent mass similar to that of the human body, but this does not imply that the body moves in the same manner as the masses in this optimized two-degree-of-freedom model.

  16. CAN THE MASSES OF ISOLATED PLANETARY-MASS GRAVITATIONAL LENSES BE MEASURED BY TERRESTRIAL PARALLAX?

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, M.; Botzler, C. S.; Bray, J. C.; Cherrie, J. M.; Rattenbury, N. J. [Department of Physics, University of Auckland, Private Bag 92019, Auckland 1142 (New Zealand); Philpott, L. C. [Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4 (Canada); Abe, F.; Muraki, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Albrow, M. D. [Department of Physics and Astronomy, University of Canterbury, P.O. Box 4800, Christchurch 8020 (New Zealand); Bennett, D. P. [Department of Physics, 225 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556 (United States); Bond, I. A. [Institute for Information and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland 1330 (New Zealand); Christie, G. W.; Natusch, T. [Auckland Observatory, PO Box 180, Royal Oak, Auckland 1345 (New Zealand); Dionnet, Z. [Université d' Orsay, bat 470, F-91400 Orsay (France); Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Han, C. [Department of Physics, Chungbuk National University, 410 Seongbong-Rho, Hungduk-Gu, Chongju 371-763 (Korea, Republic of); Heyrovský, D. [Institute of Theoretical Physics, Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague (Czech Republic); McCormick, J. M. [Farm Cove Observatory, 2/24 Rapallo Place, Pakuranga, Auckland 2012 (New Zealand); Moorhouse, D. M. [Kumeu Observatory, Kumeu (New Zealand); Skowron, J., E-mail: mfre070@aucklanduni.ac.nz [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478, Warszawa (Poland); and others

    2015-02-01

    Recently Sumi et al. reported evidence for a large population of planetary-mass objects (PMOs) that are either unbound or orbit host stars in orbits ≥10 AU. Their result was deduced from the statistical distribution of durations of gravitational microlensing events observed by the MOA collaboration during 2006 and 2007. Here we study the feasibility of measuring the mass of an individual PMO through microlensing by examining a particular event, MOA-2011-BLG-274. This event was unusual as the duration was short, the magnification high, the source-size effect large, and the angular Einstein radius small. Also, it was intensively monitored from widely separated locations under clear skies at low air masses. Choi et al. concluded that the lens of the event may have been a PMO but they did not attempt a measurement of its mass. We report here a re-analysis of the event using re-reduced data. We confirm the results of Choi et al. and attempt a measurement of the mass and distance of the lens using the terrestrial parallax effect. Evidence for terrestrial parallax is found at a 3σ level of confidence. The best fit to the data yields the mass and distance of the lens as 0.80 ± 0.30 M {sub J} and 0.80 ± 0.25 kpc respectively. We exclude a host star to the lens out to a separation ∼40 AU. Drawing on our analysis of MOA-2011-BLG-274 we propose observational strategies for future microlensing surveys to yield sharper results on PMOs including those down to super-Earth mass.

  17. Vibration Analysis of Inclined Laminated Composite Beams under Moving Distributed Masses

    Directory of Open Access Journals (Sweden)

    E. Bahmyari

    2014-01-01

    Full Text Available The dynamic response of laminated composite beams subjected to distributed moving masses is investigated using the finite element method (FEM based on the both first-order shear deformation theory (FSDT and the classical beam theory (CLT. Six and ten degrees of freedom beam elements are used to discretize the CLT and FSDT equations of motion, respectively. The resulting spatially discretized beam governing equations including the effect of inertial, Coriolis, and centrifugal forces due to moving distributed mass are evaluated in time domain by applying Newmark’s scheme. The presented approach is first validated by studying its convergence behavior and comparing the results with those of existing solutions in the literature. Then, the effect of incline angle, mass, and velocity of moving body, layer orientation, load length, and inertial, Coriolis, and centrifugal forces due to the moving distributed mass and friction force between the beam and the moving distributed mass on the dynamic behavior of inclined laminated composite beams are investigated.

  18. 2MASS J11151597+1937266: A Young, Dusty, Isolated, Planetary-mass Object with a Potential Wide Stellar Companion

    Science.gov (United States)

    Theissen, Christopher A.; Burgasser, Adam J.; Bardalez Gagliuffi, Daniella C.; Hardegree-Ullman, Kevin K.; Gagné, Jonathan; Schmidt, Sarah J.; West, Andrew A.

    2018-01-01

    We present 2MASS J11151597+1937266, a recently identified low-surface-gravity L dwarf, classified as an L2γ based on Sloan Digital Sky Survey optical spectroscopy. We confirm this spectral type with near-infrared spectroscopy, which provides further evidence that 2MASS J11151597+1937266 is a low-surface-gravity L dwarf. This object also shows significant excess mid-infrared flux, indicative of circumstellar material; and its strong Hα emission (EWHα = 560 ± 82 Å) is an indicator of enhanced magnetic activity or weak accretion. Comparison of its spectral energy distribution to model photospheres yields an effective temperature of {1724}-38+184 {{K}}. We also provide a revised distance estimate of 37 ± 6 pc using a spectral type–luminosity relationship for low-surface-gravity objects. The three-dimensional galactic velocities and positions of 2MASS J11151597+1937266 do not match any known young association or moving group. Assuming a probable age in the range of 5–45 Myr, the model-dependent estimated mass of this object is between 7 and 21 M Jup, making it a potentially isolated planetary-mass object. We also identify a candidate co-moving, young stellar companion, 2MASS J11131089+2110086.

  19. Concept study of a novel energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI) device for vibration control of harmonically-excited structures

    International Nuclear Information System (INIS)

    Salvi, Jonathan; Giaralis, Agathoklis

    2016-01-01

    A novel dynamic vibration absorber (DVA) configuration is introduced for simultaneous vibration suppression and energy harvesting from oscillations typically exhibited by large-scale low-frequency engineering structures and structural components. The proposed configuration, termed energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI) comprises a mass grounded via an in-series electromagnetic motor (energy harvester)-inerter layout, and attached to the primary structure through linear spring and damper in parallel connection. The governing equations of motion are derived and solved in the frequency domain, for the case of harmonically-excited primary structures, here modelled as damped single-degree- of-freedom (SDOF) systems. Comprehensive parametric analyses proved that by varying the mass amplification property of the grounded inerter, and by adjusting the stiffness and the damping coefficients using simple optimum tuning formulae, enhanced vibration suppression (in terms of primary structure peak displacement) and energy harvesting (in terms of relative velocity at the terminals of the energy harvester) may be achieved concurrently and at nearresonance frequencies, for a fixed attached mass. Hence, the proposed EH-TMDI allows for relaxing the trade-off between vibration control and energy harvesting purposes, and renders a dual-objective optimisation a practically-feasible, reliable task. (paper)

  20. Effect of increased left ventricle mass on ischemia assessment in electrocardiographic signals: rabbit isolated heart study

    Czech Academy of Sciences Publication Activity Database

    Ronzhina, M.; Olejníčková, Veronika; Stračina, T.; Nováková, M.; Janoušek, O.; Hejč, J.; Kolářová, J.; Hlaváčová, M.; Paulová, H.

    2017-01-01

    Roč. 17, Aug 4 (2017), č. článku 216. ISSN 1471-2261 Institutional support: RVO:67985823 Keywords : myocardial ischemia detection * increased left ventricular mass * electrogram * ROC analysis * isolated heart * rabbit Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery OBOR OECD: Physiology (including cytology) Impact factor: 1.832, year: 2016

  1. Experimental and analytical study on vibration control effects of eddy-current tuned mass dampers under seismic excitations

    Science.gov (United States)

    Lu, Zheng; Huang, Biao; Zhang, Qi; Lu, Xilin

    2018-05-01

    Eddy-current tuned mass dampers (EC-TMDs) are non-contacting passive control devices and are developed on the basis of conventional tuned mass dampers. They comprise a solid mass, a stiffness element, and a damping element, wherein the damping mechanism originates from eddy currents. By relative motion between a non-magnetic conductive metal and a permanent magnet in a dynamic system, a time-varying magnetic field is induced in the conductor, thereby generating eddy currents. The eddy currents induce a magnetic field with opposite polarity, causing repulsive forces, i.e., damping forces. This technology can overcome the drawbacks of conventional tuned mass dampers, such as limited service life, deterioration of mechanical properties, and undesired additional stiffness. The experimental and analytical study of this system installed on a multi-degree-of-freedom structure is presented in this paper. A series of shaking table tests were conducted on a five-story steel-frame model with/without an EC-TMD to evaluate the effectiveness and performance of the EC-TMD in suppressing the vibration of the model under seismic excitations. The experimental results show that the EC-TMD can effectively reduce the displacement response, acceleration response, interstory drift ratio, and maximum strain of the columns under different earthquake excitations. Moreover, an analytical method was proposed on the basis of electromagnetic and structural dynamic theories. A comparison between the test and simulation results shows that the simulation method can be used to estimate the response of structures with an EC-TMD under earthquake excitations with acceptable accuracy.

  2. The BANYAN-Sigma Bayesian classifier and the search for isolated planetary-mass objects

    Science.gov (United States)

    Gagné, Jonathan

    2018-01-01

    I will present new developments in the construction of a Bayesian classification tool to identify members of 22 young associations within 150 pc from partially complete kinematic data sets such as Gaia-DR1 and DR2. The new BANYAN-Sigma tool makes it possible to quickly analyze massive data sets and yields a better classification performance than all its predecessors. It will open the door to large-scale surveys to complete the stellar and substellar populations of nearby associations, which will provide deep insights in the low-mass end of the initial mass function and valuable age-calibrated targets for exoplanet surveys.I will also presents preliminary results of a search for T-type isolated planetary-mass objects in these young associations, based on BANYAN-Sigma and a cross-match between the AllWISE and 2MASS-Reject catalogs.

  3. New method for laser driven ion acceleration with isolated, mass-limited targets

    International Nuclear Information System (INIS)

    Paasch-Colberg, T.; Sokollik, T.; Gorling, K.; Eichmann, U.; Steinke, S.; Schnuerer, M.; Nickles, P.V.; Andreev, A.; Sandner, W.

    2011-01-01

    A new technique to investigate laser driven ion acceleration with fully isolated, mass-limited glass spheres with a diameter down to 8μm is presented. A Paul trap was used to prepare a levitating glass sphere for the interaction with a laser pulse of relativistic intensity. Narrow-bandwidth energy spectra of protons and oxygen ions have been observed and were attributed to specific acceleration field dynamics in case of the spherical target geometry. A general limiting mechanism has been found that explains the experimentally observed ion energies for the mass-limited target.

  4. Optical and Near-infrared Spectra of σ Orionis Isolated Planetary-mass Objects

    Energy Technology Data Exchange (ETDEWEB)

    Zapatero Osorio, M. R. [Centro de Astrobiología (CSIC-INTA), Crta. Ajalvir km 4, E-28850 Torrejón de Ardoz, Madrid (Spain); Béjar, V. J. S. [Instituto de Astrofísica de Canarias, C/. Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Ramírez, K. Peña, E-mail: mosorio@cab.inta-csic.es, E-mail: vbejar@iac.es, E-mail: karla.pena@uantof.cl [Unidad de Astronomía de la Universidad de Antofagasta, Av. U. de Antofagasta. 02800 Antofagasta (Chile)

    2017-06-10

    We have obtained low-resolution optical (0.7–0.98 μ m) and near-infrared (1.11–1.34 μ m and 0.8–2.5 μ m) spectra of 12 isolated planetary-mass candidates ( J = 18.2–19.9 mag) of the 3 Myr σ Orionis star cluster with the aim of determining the spectroscopic properties of very young, substellar dwarfs and assembling a complete cluster mass function. We have classified our targets by visual comparison with high- and low-gravity standards and by measuring newly defined spectroscopic indices. We derived L0–L4.5 and M9–L2.5 using high- and low-gravity standards, respectively. Our targets reveal clear signposts of youth, thus corroborating their cluster membership and planetary masses (6–13 M {sub Jup}). These observations complete the σ Orionis mass function by spectroscopically confirming the planetary-mass domain to a confidence level of ∼75%. The comparison of our spectra with BT-Settl solar metallicity model atmospheres yields a temperature scale of 2350–1800 K and a low surface gravity of log g ≈ 4.0 [cm s{sup −2}], as would be expected for young planetary-mass objects. We discuss the properties of the cluster’s least-massive population as a function of spectral type. We have also obtained the first optical spectrum of S Ori 70, a T dwarf in the direction of σ Orionis. Our data provide reference optical and near-infrared spectra of very young L dwarfs and a mass function that may be used as templates for future studies of low-mass substellar objects and exoplanets. The extrapolation of the σ Orionis mass function to the solar neighborhood may indicate that isolated planetary-mass objects with temperatures of ∼200–300 K and masses in the interval 6–13 M {sub Jup} may be as numerous as very low-mass stars.

  5. Cellular metabolic rates from primary dermal fibroblast cells isolated from birds of different body masses.

    Science.gov (United States)

    Jimenez, Ana Gabriela; Williams, Joseph B

    2014-10-01

    The rate of metabolism is the speed at which organisms use energy, an integration of energy transformations within the body; it governs biological processes that influence rates of growth and reproduction. Progress at understanding functional linkages between whole organism metabolic rate and underlying mechanisms that influence its magnitude has been slow despite the central role this issue plays in evolutionary and physiological ecology. Previous studies that have attempted to relate how cellular processes translate into whole-organism physiology have done so over a range of body masses of subjects. However, the data still remains controversial when observing metabolic rates at the cellular level. To bridge the gap between these ideas, we examined cellular metabolic rate of primary dermal fibroblasts isolated from 49 species of birds representing a 32,000-fold range in body masses to test the hypothesis that metabolic rate of cultured cells scales with body size. We used a Seahorse XF-96 Extracellular flux analyzer to measure cellular respiration in fibroblasts. Additionally, we measured fibroblast size and mitochondrial content. We found no significant correlation between cellular metabolic rate, cell size, or mitochondrial content and body mass. Additionally, there was a significant relationship between cellular basal metabolic rate and proton leak in these cells. We conclude that metabolic rate of cells isolated in culture does not scale with body mass, but cellular metabolic rate is correlated to growth rate in birds. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Influence of gravitational and vibrational convection on the heat- and mass transfer in the melt during crystal growing by Bridgman and floating zone methods

    Science.gov (United States)

    Fedorov, Oleg

    2016-07-01

    Space materials science is one of the priorities of different national and international space programs. The physical processes of heat and mass transfer in microgravity (including effect of g-jitter) is far from complete clarity, especially for important practical technology for producing crystals from the melt. The idea of the impact on crystallizing melt by low frequency vibration includes not only the possibility to suppress unwanted microaccelerations, but also to actively influence the structure of the crystallization front. This approach is one of the most effective ways to influence the quality of materials produced in flight conditions. The subject of this work is the effect of vibrations on the thermal and hydrodynamic processes during crystal growth using Bridgman and floating zone techniques, which have the greatest prospect of practical application in space. In the present approach we consider the gravitational convection, Marangoni convection, as well as the effect of vibration on the melt for some special cases. The results of simulation were compared with some experimental data obtained by the authors using a transparent model substance - succinonitrile (Bridgman method), and silicon (floating zone method). Substances used, process parameters and characteristics of the experimental units correspond the equipment developed for onboard research and serve as a basis for selecting optimum conditions vibration exposure as a factor affecting the solidification pattern. The direction of imposing vibrations coincides with the axis of the crystal, the frequency is presented by the harmonic law, and the force of gravity was varied by changing its absolute value. Mathematical model considered axisymmetric approximation of joint convective-conductive energy transfer in the system crystal - melt. Upon application of low-frequency oscillations of small amplitude along the axis of growing it was found the suppression of the secondary vortex flows near the

  7. Simulation Study on Train-Induced Vibration Control of a Long-Span Steel Truss Girder Bridge by Tuned Mass Dampers

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2014-01-01

    Full Text Available Train-induced vibration of steel truss bridges is one of the key issues in bridge engineering. This paper talks about the application of tuned mass damper (TMD on the vibration control of a steel truss bridge subjected to dynamic train loads. The Nanjing Yangtze River Bridge (NYRB is taken as the research object and a recorded typical train load is included in this study. With dynamic finite element (FE method, the real-time dynamic responses of NYRB are analyzed based on a simplified train-bridge time-varying system. Thereinto, two cases including single train moving at one side and two trains moving oppositely are specifically investigated. According to the dynamic characteristics and dynamic responses of NYRB, the fourth vertical bending mode is selected as the control target and the parameter sensitivity analysis on vibration control efficiency with TMD is conducted. Using the first-order optimization method, the optimal parameters of TMD are then acquired with the control efficiency of TMD, the static displacement of Midspan, expenditure of TMDs, and manufacture difficulty of the damper considered. Results obtained in this study can provide references for the vibration control of steel truss bridges.

  8. Matrix isolation-infrared and mass spectrometric studies of high-temperature molecules

    International Nuclear Information System (INIS)

    Dickinson, S.

    1987-08-01

    Matrix isolation-infrared spectroscopy and mass spectrometry have been developed at AEE Winfrith to study the high-temperature vapour species which could be generated during a hypothetical severe reactor accident. The principles of the techniques and the instruments are described in detail, and examples of their application to specific systems discussed. Although these examples refer to high-temperature chemical species which are relevant to reactor safety assessments, the techniques are equally applicable to other processes where the characterisation of transient vapour-phase species is required. (author)

  9. Analytical modeling of large amplitude free vibration of non-uniform beams carrying a both transversely and axially eccentric tip mass

    Science.gov (United States)

    Malaeke, Hasan; Moeenfard, Hamid

    2016-03-01

    The objective of this paper is to study large amplitude flexural-extensional free vibration of non-uniform cantilever beams carrying a both transversely and axially eccentric tip mass. The effects of variable axial force is also taken into account. Hamilton's principle is utilized to obtain the partial differential equations governing the nonlinear vibration of the system as well as the corresponding boundary conditions. A numerical finite difference scheme is proposed to find the natural frequencies and mode shapes of the system which is validated specifically for a beam with linearly varying cross section. Using a single mode approximation in conjunction with the Lagrange method, the governing equations are reduced to a set of two nonlinear ordinary differential equations in terms of end displacement components of the beam which are coupled due to the presence of the transverse eccentricity. These temporal coupled equations are then solved analytically using the multiple time scales perturbation technique. The obtained analytical results are compared with the numerical ones and excellent agreement is observed. The qualitative and quantitative knowledge resulting from this research is expected to enable the study of the effects of eccentric tip mass and non-uniformity on the large amplitude flexural-extensional vibration of beams for improved dynamic performance.

  10. Koch’s Disease Presenting as an Isolated Testicular Mass- An Unusual Occurance

    Science.gov (United States)

    Das, Deepak; Sherpa, Mingma

    2014-01-01

    Isolated testicular tuberculosis (TB) is rarely seen. A 72-year-old, farmer presented with complaints of discharging sinus from scrotum along with pain and swelling. The patient had no sign of tuberculosis. On examination a hard mass arising from the left testis was noted along with a discharging fistula on the overlying scrotal skin. Chest x-ray and ultrasound examination of the abdomen were within normal limits. After assessing the testicular mass, an informed consent was taken thereafter left orchiectomy and fistulectomy performed. Histopathological examination revealed caseating granulomas along with numerous Langhan’s giant cells consistent with tuberculous orchitis. The patient received anti-TB treatment for six months. The rare involvement of testis by tuberculosis needs to be mentioned. PMID:25386448

  11. Koch's Disease Presenting as an Isolated Testicular Mass- An Unusual Occurance.

    Science.gov (United States)

    Lamichaney, Rachna; Das, Deepak; Sherpa, Mingma

    2014-09-01

    Isolated testicular tuberculosis (TB) is rarely seen. A 72-year-old, farmer presented with complaints of discharging sinus from scrotum along with pain and swelling. The patient had no sign of tuberculosis. On examination a hard mass arising from the left testis was noted along with a discharging fistula on the overlying scrotal skin. Chest x-ray and ultrasound examination of the abdomen were within normal limits. After assessing the testicular mass, an informed consent was taken thereafter left orchiectomy and fistulectomy performed. Histopathological examination revealed caseating granulomas along with numerous Langhan's giant cells consistent with tuberculous orchitis. The patient received anti-TB treatment for six months. The rare involvement of testis by tuberculosis needs to be mentioned.

  12. LEO P: HOW MANY METALS CAN A VERY LOW MASS, ISOLATED GALAXY RETAIN?

    Energy Technology Data Exchange (ETDEWEB)

    McQuinn, Kristen B. W.; Skillman, Evan D. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S.E., University of Minnesota, Minneapolis, MN 55455 (United States); Dolphin, Andrew [Raytheon Company, 1151 E. Hermans Road, Tucson, AZ 85756 (United States); Cannon, John M. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Salzer, John J.; Rhode, Katherine L. [Department of Astronomy, Indiana University, 727 East 3rd Street, Bloomington, IN 47405 (United States); Adams, Elizabeth A. K. [ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo (Netherlands); Berg, Danielle [Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States); Giovanelli, Riccardo; Haynes, Martha P., E-mail: kmcquinn@astro.as.utexas.edu [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States)

    2015-12-20

    Leo P is a gas-rich dwarf galaxy with an extremely low gas-phase oxygen abundance (3% solar). The isolated nature of Leo P enables a quantitative measurement of metals lost solely due to star formation feedback. We present an inventory of the oxygen atoms in Leo P based on the gas-phase oxygen abundance measurement, the star formation history (SFH), and the chemical enrichment evolution derived from resolved stellar populations. The SFH also provides the total amount of oxygen produced. Overall, Leo P has retained 5% of its oxygen; 25% of the retained oxygen is in the stars while 75% is in the gas phase. This is considerably lower than the 20%–25% calculated for massive galaxies, supporting the trend for less efficient metal retention for lower-mass galaxies. The retention fraction is higher than that calculated for other alpha elements (Mg, Si, Ca) in dSph Milky Way satellites of similar stellar mass and metallicity. Accounting only for the oxygen retained in stars, our results are consistent with those derived for the alpha elements in dSph galaxies. Thus, under the assumption that the dSph galaxies lost the bulk of their gas mass through an environmental process such as tidal stripping, the estimates of retained metal fractions represent underestimates by roughly a factor of four. Because of its isolation, Leo P provides an important datum for the fraction of metals lost as a function of galaxy mass due to star formation.

  13. Data set for the mass spectrometry based exoproteome analysis of Aspergillus flavus isolates

    Directory of Open Access Journals (Sweden)

    Ramu Muthu Selvam

    2015-03-01

    Full Text Available Aspergillus flavus is one of the predominant causative organisms of mycotic keratitis in tropical parts of the world. Extracellular proteins are the earliest proteins that come in contact with the host and have a role in the infection process. Exoproteins of A. flavus isolated from infected cornea, sputum and a saprophyte were pooled and identified using high resolution mass spectrometry in order to get the total exoproteome from cultures isolated from different sources. A total of 637 proteins was identified from the pooled A. flavus exoproteome. Analysis based on GO annotations of the 637 identified proteins revealed that hydrolases form the predominant class of proteins in the exoproteome. Interestingly, a greater proportion of the exoproteins seem to be secreted through the non-classical pathways. This data represent the first in-depth analysis of the representative A. flavus exoproteome of a large set of isolates from distinct sources. This data have been deposited to the ProteomeXchange with identifier PXD001296.

  14. Proposal and experimental validation of analytical models for seismic and vibration isolation devices in nuclear and non-nuclear facilities

    International Nuclear Information System (INIS)

    Serino, G.; Bonacina, G.; Bettinali, F.

    1993-01-01

    Two analytical-experimental models of HDLRBs having different levels of approximations are presented. Comparison with available experimental data shows that a non-linear hysteretic model, defined by three rubber parameters only, allows a very good complete simulation of the dynamic behavior of the isolation devices. A simpler equivalent linear viscous model reproduces less exactly the experimental behavior, but permits a good prediction of peak response values in the earthquake analysis of an isolated structure, if bearing stiffness and damping parameters are properly selected. The models have been used in preliminary design and subsequent check of the isolation system of two different types of Gas-Insulated Electric Substations (GIS), in view of possible future installation of isolated GISes in areas of high seismic risk. (author)

  15. Numerical simulation of lead devices for seismic isolation and vibration control on their damping characteristics. Development of lead material model under cyclic large deformation

    International Nuclear Information System (INIS)

    Matsuda, Akihiro; Yabana, Shuichi; Borst, Rene de

    2004-01-01

    In order to predict the mechanical properties of lead devices for seismic isolation and vibration control, especially damping behavior under cyclic loading using numerical simulation, cyclic shear loading tests and uniaxial tensile loading tests were performed, and a new material model was proposed with the use of the both test results. Until now, it has been difficult to evaluate mechanical properties of lead material under cyclic loading by uniaxial tensile loading test because local deformations appeared with the small tensile strain. Our shear cyclic loading tests for lead material enabled practical evaluation of its mechanical properties under cyclic large strain which makes it difficult to apply uniaxial test. The proposed material model was implemented into a finite element program, and it was applied to numerical simulation of mechanical properties of lead dampers and rubber bearings with a lead plug. The numerical simulations and the corresponding laboratory loading tests showed good agreement, which proved the applicability of the proposed model. (author)

  16. Simulations of isolated dwarf galaxies formed in dark matter halos with different mass assembly histories

    International Nuclear Information System (INIS)

    González-Samaniego, A.; Avila-Reese, V.; Rodríguez-Puebla, A.; Valenzuela, O.; Colín, P.

    2014-01-01

    We present zoom-in N-body/hydrodynamics resimulations of dwarf galaxies formed in isolated cold dark matter (CDM) halos with the same virial mass (M v ≈ 2.5 × 10 10 M ☉ ) at redshift z = 0. Our goals are to (1) study the mass assembly histories (MAHs) of the halo, stellar, and gaseous components; and (2) explore the effects of the halo MAHs on the stellar/baryonic assembly of simulated dwarfs. Overall, the dwarfs are roughly consistent with observations. More specific results include: (1) the stellar-to-halo mass ratio remains roughly constant since z ∼ 1, i.e., the stellar MAHs closely follow halo MAHs. (2) The evolution of the galaxy gas fractions, f g , are episodic, showing that the supernova-driven outflows play an important role in regulating f g —and hence, the star formation rate (SFR)—however, in most cases, a large fraction of the gas is ejected from the halo. (3) The star formation histories are episodic with changes in the SFRs, measured every 100 Myr, of factors of 2-10 on average. (4) Although the dwarfs formed in late assembled halos show more extended SF histories, their z = 0 specific SFRs are still below observations. (5) The inclusion of baryons most of the time reduces the virial mass by 10%-20% with respect to pure N-body simulations. Our results suggest that rather than increasing the strength of the supernova-driven outflows, processes that reduce the star formation efficiency could help to solve the potential issues faced by CDM-based simulations of dwarfs, such as low values of the specific SFR and high stellar masses.

  17. Simulations of isolated dwarf galaxies formed in dark matter halos with different mass assembly histories

    Energy Technology Data Exchange (ETDEWEB)

    González-Samaniego, A.; Avila-Reese, V.; Rodríguez-Puebla, A.; Valenzuela, O. [Instituto de Astronomía, Universidad Nacional Autónoma de México, A.P. 70-264, 04510 México D. F. (Mexico); Colín, P. [Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, A.P. 72-3 (Xangari), Morelia, Michoacán 58089 (Mexico)

    2014-04-10

    We present zoom-in N-body/hydrodynamics resimulations of dwarf galaxies formed in isolated cold dark matter (CDM) halos with the same virial mass (M{sub v} ≈ 2.5 × 10{sup 10} M {sub ☉}) at redshift z = 0. Our goals are to (1) study the mass assembly histories (MAHs) of the halo, stellar, and gaseous components; and (2) explore the effects of the halo MAHs on the stellar/baryonic assembly of simulated dwarfs. Overall, the dwarfs are roughly consistent with observations. More specific results include: (1) the stellar-to-halo mass ratio remains roughly constant since z ∼ 1, i.e., the stellar MAHs closely follow halo MAHs. (2) The evolution of the galaxy gas fractions, f{sub g} , are episodic, showing that the supernova-driven outflows play an important role in regulating f{sub g} —and hence, the star formation rate (SFR)—however, in most cases, a large fraction of the gas is ejected from the halo. (3) The star formation histories are episodic with changes in the SFRs, measured every 100 Myr, of factors of 2-10 on average. (4) Although the dwarfs formed in late assembled halos show more extended SF histories, their z = 0 specific SFRs are still below observations. (5) The inclusion of baryons most of the time reduces the virial mass by 10%-20% with respect to pure N-body simulations. Our results suggest that rather than increasing the strength of the supernova-driven outflows, processes that reduce the star formation efficiency could help to solve the potential issues faced by CDM-based simulations of dwarfs, such as low values of the specific SFR and high stellar masses.

  18. Breast Cancer Mimic: Cutaneous B-Cell Lymphoma Presenting as an Isolated Breast Mass

    Directory of Open Access Journals (Sweden)

    Margaret Taghavi

    2014-10-01

    Full Text Available Background: Primary cutaneous B-cell lymphoma typically localizes to the skin, and dissemination to internal organs is rare. Lymphomatous involvement of the breasts is also rare. We describe the clinical and radiological findings of an unusual case of primary cutaneous B-cell lymphoma presenting as an isolated breast mass without associated skin changes. Case Presentation: The patient was a 55-year-old Caucasian female who initially presented with cutaneous B-cell lymphoma around her eyes and forehead with recurrence involving the skin between her breasts. Three years after terminating treatment due to a lack of symptoms, she presented for an annual screening mammogram that found a new mass in her upper inner right breast without imaging signs of cutaneous extension. On physical examination, there were no corresponding skin findings. Due to the suspicious imaging features of the mass that caused concern for primary breast malignancy, she underwent a core biopsy which revealed cutaneous B-cell lymphoma. Conclusion: When evaluating patients with a systemic disease who present with findings atypical for that process, it is important to still consider the systemic disease as a potential etiology, particularly with lymphoma given its reputation as a great mimicker.

  19. Forming the stress state of a vibroisolated building in the process of mounting rubber steel vibration isolator

    Directory of Open Access Journals (Sweden)

    Dashevskiy Mikhail Aronovich

    2015-12-01

    Full Text Available The necessity to specificate the formation process of stress-strain state of buildings in the construction process is a new problem which requires including real production characteristics going beyond calculation models into calculation methods. Today the construction process lacks this specification. When mounting vibroisolators the stress-strein of a structure state is changing. The mounting method of vibroisolators is patented and consists in multistage successive compression loading of each vibroisolator with the constant speed and following fixation of this displacement. The specified engineering method of rubber-steel pads calculation in view of change of their form during deformation, nonlinearity, rheological processes is offered. Resilient pads look like rubber plates rectangular in plane reinforced on the basic surfaces with metal sheets. The influence of a time-variable static load and free vibrations of loaded pads are considered.

  20. Tandem Mass Spectrometry Detection of Quorum Sensing Activity in Multidrug Resistant Clinical Isolate Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2014-01-01

    Full Text Available Many Proteobacteria communicate via production followed by response of quorum sensing molecules, namely, N-acyl homoserine lactones (AHLs. These molecules consist of a lactone moiety with N-acyl side chain with various chain lengths and degrees of saturation at C-3 position. AHL-dependent QS is often associated with regulation of diverse bacterial phenotypes including the expression of virulence factors. With the use of biosensor and high resolution liquid chromatography tandem mass spectrometry, the AHL production of clinical isolate A. baumannii 4KT was studied. Production of short chain AHL, namely, N-hexanoyl-homoserine lactone (C6-HSL and N-octanoyl-homoserine lactone (C8-HSL, was detected.

  1. The characterisation of molecular boric acid by mass spectrometry and matrix isolation-infrared spectroscopy

    International Nuclear Information System (INIS)

    Ogden, J.S.; Young, N.A.; Bowsher, B.R.

    1987-10-01

    Boric acid (H 3 BO 3 ) is used as a soluble neutron absorber in the coolant of pressurised water reactors and will be an important species in defining the fission product chemistry of severe reactor accidents. Mass spectrometry and matrix isolation-infrared spectroscopy have been used to characterise boric acid in the vapour phase and hence assess the implications of any chemical interactions. Crystalline orthoboric acid vaporises to yield molecular H 3 BO 3 when heated in vacuum to approximately 40 0 C. The infrared spectrum of the vapour species isolated in low-temperature nitrogen matrices shows characteristic absorptions at 3668.5 (E'), 1426.2 (E'), 1009.9 (E'), 675.0 (A''), 513.8 (A'') and 448.9 (E') cm -1 , consistent with C 3h symmetry. These spectral assignments are supported by extensive isotope labelling, and by a partial normal co-ordinate analysis. These data will be used to quantify specific thermodynamic functions and hence assist in determining the magnitude of reactions such as boric acid with caesium iodide. (author)

  2. Isolation of {sup 163}Ho from dysprosium target material by HPLC for neutrino mass measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mocko, Veronika; Taylor, Wayne A.; Nortier, Francois M.; Engle, Jonathan W.; Pollington, Anthony D.; Kunde, Gerd J.; Rabin, Michael W.; Birnbaum, Eva R. [Los Alamos National Laboratory, Los Alamos, NM (United States). Chemistry Div.; Barnhart, Todd E.; Nickles, Robert J. [Univ. Wisconsinn, Madison, WI (United States). Dept. of Medical Physics

    2015-07-01

    The rare earth isotope {sup 163}Ho is of interest for neutrino mass measurements. This report describes the isolation of {sup 163}Ho from a proton-irradiated dysprosium target and its purification. A Dy metal target was irradiated with 16 MeV protons for 10 h. After target dissolution, {sup 163}Ho was separated from the bulk Dy via cation-exchange high performance liquid chromatography using 70 mmol dm{sup -3} α-hydroxyisobutyric acid as the mobile phase. Subsequent purification of the collected Ho fraction was performed to remove the α-hydroxyisobutyrate chelating agent and to concentrate the Ho in a low ionic strength aqueous matrix. The final solution was characterized by MC-ICP-MS to determine the {sup 163}Ho/{sup 165}Ho ratio, {sup 163}Ho and the residual Dy content. The HPLC purification process resulted in a decontamination factor 1.4 x 10{sup 5} for Dy. The isolated Ho fraction contained 24.8 ± 1.3 ng of {sup 163}Ho corresponding to holmium recovery of 72 ± 3%.

  3. Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations

    Science.gov (United States)

    Karthikeyan, N.; Joseph Prince, J.; Ramalingam, S.; Periandy, S.

    2015-03-01

    In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The 13C and 1H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied.

  4. Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations.

    Science.gov (United States)

    Karthikeyan, N; Prince, J Joseph; Ramalingam, S; Periandy, S

    2015-03-15

    In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The (13)C and (1)H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  5. Mass-selective isolation of ions stored in a quadrupole ion trap. A simulation study

    Science.gov (United States)

    March, Raymond E.; Londry, Frank A.; Alfred, Roland L.; Franklin, Anthony M.; Todd, John F. J.

    1992-01-01

    Trajectories of single ions stored in the quadrupole ion trap have been calculated using a simulation program described as the specific program for quadrupolar resonance (SPQR). Previously, the program has been used for the investigation of quadrupolar resonance excitation of ions with a static working point (or co-ordinates) in the stability diagram. The program has been modified to accommodate continuous d.c. and/or r.f. voltage ramps so as to permit calculation of ion trajectories while the working point is being changed. The modified program has been applied to the calculation of ion trajectories during ion isolation, or mass-selective storage, in the ion trap. The quadrupolar resonance excitation aspect of SPQR was not used in this study. Trajectories are displayed as temporal variations of ion kinetic energy, and axial and radial excursions from the centre of the ion trap. The working points of three ion species (m/z 144, 146 and 148), located initially on the qz, axis with qz [approximate] 0.12, were moved to the vicinity of the upper apex by a combination of r.f. and d.c. voltages applied in succession. Stable trajectories were maintained only for the ion species of m/z 146 for which the working point lay within this apex; the other ion species were ejected either radially or axially. The d.c. voltage was then reduced to zero so as to restore the working point of the isolated ion species to the qz axis. The amplitude of the r.f voltage was reduced to its initial value so as to retrieve the initial working point for m/z 146. The process extended over a real time of 2.9 ms, and was collision-free. The trajectory of the isolated ion was stable during this process; the ion species with m/z value lower than that of the target ion, that is, m/z 144, was ejected axially at the [beta]z = 1 boundary, while that with higher m/z value, that is, m/z 148, was ejected radially at the [beta]r = 0 boundary, as expected. The moderating effects of buffer gas were not taken

  6. NEW ISOLATED PLANETARY-MASS OBJECTS AND THE STELLAR AND SUBSTELLAR MASS FUNCTION OF THE σ ORIONIS CLUSTER

    International Nuclear Information System (INIS)

    Peña Ramírez, K.; Béjar, V. J. S.; Zapatero Osorio, M. R.; Martín, E. L.; Petr-Gotzens, M. G.

    2012-01-01

    We report on our analysis of the VISTA Orion ZY JHK s photometric data (completeness magnitudes of Z = 22.6 and J = 21.0 mag) focusing on a circular area of 2798.4 arcmin 2 around the young σ Orionis star cluster (∼3 Myr, ∼352 pc, and solar metallicity). The combination of the VISTA photometry with optical, WISE and Spitzer data allows us to identify a total of 210 σ Orionis member candidates with masses in the interval 0.25-0.004 M ☉ , 23 of which are new planetary-mass object findings. These discoveries double the number of cluster planetary-mass candidates known so far. One object has colors compatible with a T spectral type. The σ Orionis cluster harbors about as many brown dwarfs (69, 0.072-0.012 M ☉ ) and planetary-mass objects (37, 0.012-0.004 M ☉ ) as very low mass stars (104, 0.25-0.072 M ☉ ). Based on Spitzer data, we derive a disk frequency of ∼40% for very low mass stars, brown dwarfs, and planetary-mass objects in σ Orionis. The radial density distributions of these three mass intervals are alike: all are spatially concentrated within an effective radius of 12' (1.2 pc) around the multiple star σ Ori, and no obvious segregation between disk-bearing and diskless objects is observed. Using the VISTA data and the Mayrit catalog, we derive the cluster mass spectrum (ΔN/ΔM ∼ M –α ) from ∼19 to 0.006 M ☉ (VISTA ZJ completeness), which is reasonably described by two power-law expressions with indices of α = 1.7 ± 0.2 for M > 0.35 M ☉ , and α = 0.6 ± 0.2 for M ☉ . The σ Orionis mass spectrum smoothly extends into the planetary-mass regime down to 0.004 M ☉ . Our findings of T-type sources ( ☉ ) in the VISTA σ Orionis exploration appear to be smaller than what is predicted by the extrapolation of the cluster mass spectrum down to the survey J-band completeness.

  7. NEW ISOLATED PLANETARY-MASS OBJECTS AND THE STELLAR AND SUBSTELLAR MASS FUNCTION OF THE {sigma} ORIONIS CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Pena Ramirez, K.; Bejar, V. J. S. [Instituto de Astrofisica de Canarias, C/. Via Lactea s/n, E-38205 La Laguna, Tenerife (Spain); Zapatero Osorio, M. R.; Martin, E. L. [Centro de Astrobiologia (CSIC-INTA), Crta. Ajalvir km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Petr-Gotzens, M. G., E-mail: karla@iac.es, E-mail: vbejar@iac.es, E-mail: mosorio@cab.inta-csic.es, E-mail: ege@cab.inta-csic.es, E-mail: mpetr@eso.org [European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei Muenchen (Germany)

    2012-07-20

    We report on our analysis of the VISTA Orion ZY JHK{sub s} photometric data (completeness magnitudes of Z = 22.6 and J = 21.0 mag) focusing on a circular area of 2798.4 arcmin{sup 2} around the young {sigma} Orionis star cluster ({approx}3 Myr, {approx}352 pc, and solar metallicity). The combination of the VISTA photometry with optical, WISE and Spitzer data allows us to identify a total of 210 {sigma} Orionis member candidates with masses in the interval 0.25-0.004 M{sub Sun }, 23 of which are new planetary-mass object findings. These discoveries double the number of cluster planetary-mass candidates known so far. One object has colors compatible with a T spectral type. The {sigma} Orionis cluster harbors about as many brown dwarfs (69, 0.072-0.012 M{sub Sun }) and planetary-mass objects (37, 0.012-0.004 M{sub Sun }) as very low mass stars (104, 0.25-0.072 M{sub Sun }). Based on Spitzer data, we derive a disk frequency of {approx}40% for very low mass stars, brown dwarfs, and planetary-mass objects in {sigma} Orionis. The radial density distributions of these three mass intervals are alike: all are spatially concentrated within an effective radius of 12' (1.2 pc) around the multiple star {sigma} Ori, and no obvious segregation between disk-bearing and diskless objects is observed. Using the VISTA data and the Mayrit catalog, we derive the cluster mass spectrum ({Delta}N/{Delta}M {approx} M{sup -{alpha}}) from {approx}19 to 0.006 M{sub Sun} (VISTA ZJ completeness), which is reasonably described by two power-law expressions with indices of {alpha} = 1.7 {+-} 0.2 for M > 0.35 M{sub Sun }, and {alpha} = 0.6 {+-} 0.2 for M < 0.35 M{sub Sun }. The {sigma} Orionis mass spectrum smoothly extends into the planetary-mass regime down to 0.004 M{sub Sun }. Our findings of T-type sources (<0.004 M{sub Sun }) in the VISTA {sigma} Orionis exploration appear to be smaller than what is predicted by the extrapolation of the cluster mass spectrum down to the survey J

  8. Isolated orbital mass as the primary presentation of a triple-hit lymphoma transformed from a systemic follicular lymphoma.

    Science.gov (United States)

    Zhou, Xiao Yi; Lu, Xinyan; Raparia, Kirtee; Chen, Yi-Hua

    2018-06-01

    Triple-hit lymphoma is a highly aggressive B-cell lymphoma. We report a case of triple-hit lymphoma transformed from systemic follicular lymphoma (FL) after 9-year remission and presented primarily as an isolated orbital mass without systemic symptoms or lymphadenopathy. A 58-year-old female presented with intermittent vertical binocular diplopia, left upper eyelid swelling and pain and was found to have a 2.9 cm orbital mass. Histological section revealed a CD10-positive large B-cell lymphoma, consistent with transformation of FL. Fluorescent in situ hybridization (FISH) analysis demonstrated rearrangements involving C-MYC, BCL-2 and BCL-6 genes, indicating a high grade, triple-hit lymphoma. Triple-hit lymphoma transformed from a low-grade lymphoma may initially present as an isolated orbital mass without systemic evidence of transformation. Early recognition of double or triple-hit lymphomas is important since these patients require aggressive chemotherapy.

  9. Radiation pressure actuation of test masses

    International Nuclear Information System (INIS)

    Garoi, F; Ju, L; Zhao, C; Blair, D G

    2004-01-01

    In this paper, we investigate the use of radiation pressure force as test mass actuation for laser interferometer gravitational wave detectors. It is shown that it is viable to provide radiation pressure control on test masses for frequencies above ∼0.2 Hz in high performance vibration isolation systems. A very low mass, low frequency resonator has been used to verify that radiation pressure force is not corrupted by other forces such as due to radiometer effects

  10. Identification of Candida species isolated from vulvovaginitis using matrix assisted laser desorption ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Alizadeh, Majid; Kolecka, Anna; Boekhout, Teun; Zarrinfar, Hossein; Ghanbari Nahzag, Mohamad A; Badiee, Parisa; Rezaei-Matehkolaei, Ali; Fata, Abdolmajid; Dolatabadi, Somayeh; Najafzadeh, Mohammad J

    2017-12-01

    Vulvovaginal candidiasis (VVC) is a common problem in women. The purpose of this study was to identify Candida isolates by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) from women with vulvovaginitis that were referred to Ghaem Hospital, Mashhad, Iran. This study was conducted on 65 clinical samples isolated from women that were referred to Ghaem Hospital. All specimens were identified using phenotyping techniques, such as microscopy and culture on Sabouraud dextrose agar and corn meal agar. In addition, all isolates were processed for MALDI-TOF MS identification. Out of the 65 analyzed isolates, 61 (94%) samples were recognized by MALDI-TOF MS. However, the remaining four isolates (6%) had no reliable identification. According to the results, C. albicans (58.5%) was the most frequently isolated species, followed by C. tropicalis (16.9%), C. glabrata (7.7%), C. parapsilosis (7.7%), and guilliermondii (3.1%). As the findings indicated, MALDI TOF MS was successful in the identification of clinical Candida species. C. albicans was identified as the most common Candida species isolated from the women with VVC. Moreover, C. tropicalis was the most common species among the non- albicans Candida species.

  11. Vibration mixer

    Energy Technology Data Exchange (ETDEWEB)

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

    1983-01-01

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

  12. Effectiveness of Tuned Mass Dampers in Seismic Response Control of Isolated Bridges Including Soil-Structure Interaction

    Directory of Open Access Journals (Sweden)

    Said Elias

    Full Text Available Abstract The effect of soil-structure interaction (SSI on the dynamic responses of seismically isolated three-span continuous reinforced concrete (RC bridge is investigated. Also, tuned mass damper(s (TMD/s is/are installed to control undesirable bearing displacement, even under the SSI effect. The TMDs are placed at the mid-span of the bridge and each tuned with a modal frequency, while controlling up to first few modes as desirable. The soil surrounding the foundation of pier is modeled by frequency independent coefficients. Dynamic analysis is carried out in time domain using direct integration method. In order to specify the effects of the SSI, the responses of the non-isolated, isolated, and controlled isolated bridge are compared. It is observed that the soil surrounding the pier has significant effects on the bearing displacement of the isolated RC bridges. In addition, it is observed that the seismic responses of isolated RC bridge reduced significantly with installation of the TMDs.

  13. Nano-scale mass sensor based on the vibration analysis of a magneto-electro-elastic nanoplate resting on a visco-Pasternak substrate

    Science.gov (United States)

    Khanmirza, E.; Jamalpoor, A.; Kiani, A.

    2017-10-01

    In this paper, a magneto-electro-elastic nanoplate resting on a visco-Pasternak medium with added concentrated nanoparticles is presented as a mass nanosensor according to the vibration analysis. The MEE nanoplate is supposed to be subject to external electric voltage and magnetic potential. In order to take into account the size effect on the sensitivity of the sensor, the nonlocal elasticity theory in conjunction with the Kirchhoff plate theory is applied. Partial differential equations are derived by implementing Hamilton's variational principle. Equilibrium equations were solved analytically to determine an explicit closed-form statement for both the damped frequency shift and the relative damped frequency shift using Navier's approach. A genetic algorithm (GA) is employed to achieve the optimal added nanoparticle location to gain the most sensitivity performance of the nanosensor. Numerical studies are performed to illustrate the variation of the sensitivity property corresponding to various values of the number of attached nanoparticles, the mass of each nanoparticle, the nonlocal parameter, external electric voltage and magnetic potential, the aspect ratio, and visco-Pasternak parameters. Some numerical outcomes of this paper show that the minimum value of the damped frequency shift occurs for a certain value of the length-to-thickness ratio. Also, it is shown that the external magnetic and external electric potentials have a different effect on the sensitivity property. It is anticipated that the results reported in this work can be considered as a benchmark in future micro-structures issues.

  14. 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.

  15. Rapid and reliable MALDI-TOF mass spectrometry identification of Candida non-albicans isolates from bloodstream infections.

    Science.gov (United States)

    Pulcrano, Giovanna; Iula, Dora Vita; Vollaro, Antonio; Tucci, Alessandra; Cerullo, Monica; Esposito, Matilde; Rossano, Fabio; Catania, Maria Rosaria

    2013-09-01

    Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) fingerprinting has recently become an effective instrument for rapid microbiological diagnostics and in particular for identification of micro-organisms directly in a positive blood culture. The aim of the study was to evaluate a collection of 82 stored yeast isolates from bloodstream infection, by MALDI-TOF MS; 21 isolates were identified also directly from positive blood cultures and in the presence of other co-infecting micro-organisms. Of the 82 isolates grown on plates, 64 (76%) were correctly identified by the Vitek II system and 82 (100%) by MALDI-TOF MS; when the two methods gave different results, the isolate was identified by PCR. MALDI-TOF MS was unreliable in identifying two isolates (Candida glabrata and Candida parapsilosis) directly from blood culture; however, direct analysis from positive blood culture samples was fast and effective for the identification of yeast, which is of great importance for early and adequate treatment. © 2013. Published by Elsevier B.V. All rights reserved.

  16. Isolated orbital mass as the primary presentation of a triple-hit lymphoma transformed from a systemic follicular lymphoma

    Directory of Open Access Journals (Sweden)

    Xiao Yi Zhou

    2018-06-01

    Full Text Available Purpose: Triple-hit lymphoma is a highly aggressive B-cell lymphoma. We report a case of triple-hit lymphoma transformed from systemic follicular lymphoma (FL after 9-year remission and presented primarily as an isolated orbital mass without systemic symptoms or lymphadenopathy. Observations: A 58-year-old female presented with intermittent vertical binocular diplopia, left upper eyelid swelling and pain and was found to have a 2.9 cm orbital mass. Histological section revealed a CD10-positive large B-cell lymphoma, consistent with transformation of FL. Fluorescent in situ hybridization (FISH analysis demonstrated rearrangements involving C-MYC, BCL-2 and BCL-6 genes, indicating a high grade, triple-hit lymphoma. Conclusions and importance: Triple-hit lymphoma transformed from a low-grade lymphoma may initially present as an isolated orbital mass without systemic evidence of transformation. Early recognition of double or triple-hit lymphomas is important since these patients require aggressive chemotherapy. Keywords: Lymphoma, Triple-hit lymphoma, Orbital mass

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

    Directory of Open Access Journals (Sweden)

    Niaz Bahadur Khan

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

  18. Flow induced vibrations of piping

    International Nuclear Information System (INIS)

    Gibert, R.J.; Axisa, F.

    1977-01-01

    In order to design the supports of piping systems, estimations of the vibrations induced by the fluid conveyed through the pipes are generally needed. For that purpose it is necessary to calculate the model parameters of liquid containing pipes. In most computer codes, fluid effects are accounted for just by adding the fluid mass to the structure. This may lead to serious errors. This paper presents a method to take into account these effects, by solving a coupled mechanical-acoustical problem: the computer code TEDEL of the C.E.A /D.E.M.T. System, based on the finite-elements method, has been extended to calculate simultaneously the pressure fluctuations in the fluid and the vibrations of the pipe. By this way the mechanical-acoustical coupled eigenmodes of any piping system can be obtained. These eigenmodes are used to determine the response of the system to various sources. Equations have been written in the hypohesis that acoustical wave lengths remain large compared to the diameter of the pipe. The method has been checked by an experiment performed on the GASCOGNE loop at D.E.M.T. The piping system under test consists of a tube with four elbows. The circuit is ended at each extremity by a large vessel which performs acoustical isolation by generating modes for the pressure. Excitation of the circuit is caused by a valve located near the downstream vessel. This provides an efficient localised broad band acoustical source. The comparison between the test results and the calculations has shown that the low frequency resonant characteristics of the pipe and the vibrational amplitude at various flow-rates can be correctly predicted

  19. 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...

  20. Mass

    International Nuclear Information System (INIS)

    Quigg, Chris

    2007-01-01

    In the classical physics we inherited from Isaac Newton, mass does not arise, it simply is. The mass of a classical object is the sum of the masses of its parts. Albert Einstein showed that the mass of a body is a measure of its energy content, inviting us to consider the origins of mass. The protons we accelerate at Fermilab are prime examples of Einsteinian matter: nearly all of their mass arises from stored energy. Missing mass led to the discovery of the noble gases, and a new form of missing mass leads us to the notion of dark matter. Starting with a brief guided tour of the meanings of mass, the colloquium will explore the multiple origins of mass. We will see how far we have come toward understanding mass, and survey the issues that guide our research today.

  1. Isolation and quantification of volatiles in fish by dynamic headspace sampling and mass spectrometry

    DEFF Research Database (Denmark)

    Refsgaard, Hanne; Haahr, Anne-Mette; Jensen, Benny

    1999-01-01

    A dynamic headspace sampling method for isolation of volatiles in fish has been developed. The sample preparation involved freezing of fish tissue in liquid nitrogen, pulverizing the tissue, and sampling of volatiles from an aqueous slurry of the fish powder. Similar volatile patterns were...

  2. MICROLENS TERRESTRIAL PARALLAX MASS MEASUREMENTS: A RARE PROBE OF ISOLATED BROWN DWARFS AND FREE-FLOATING PLANETS

    International Nuclear Information System (INIS)

    Gould, Andrew; Yee, Jennifer C.

    2013-01-01

    Terrestrial microlens parallax is one of the very few methods that can measure the mass and number density of isolated dark low-mass objects, such as old free-floating planets and brown dwarfs. Terrestrial microlens parallax can be measured whenever a microlensing event differs substantially as observed from two or more well-separated sites. If the lens also transits the source during the event, then its mass can be measured. We derive an analytic expression for the expected rate of such events and then use this to derive two important conclusions. First, the rate is directly proportional to the number density of a given population, greatly favoring low-mass populations relative to their contribution to the general microlensing rate, which further scales as M 1/2 where M is the lens mass. Second, the rate rises sharply as one probes smaller source stars, despite the fact that the probability of transit falls directly with source size. We propose modifications to current observing strategies that could yield a factor of 100 increase in sensitivity to these rare events.

  3. Performance of matrix-assisted laser desorption-time of flight mass spectrometry for identification of clinical yeast isolates

    DEFF Research Database (Denmark)

    Rosenvinge, Flemming S; Dzajic, Esad; Knudsen, Elisa

    2013-01-01

    Accurate and fast yeast identification is important when treating patients with invasive fungal disease as susceptibility to antifungal agents is highly species related. Matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF-MS) provides a powerful tool with a clear potential...... spectra output, all 13 isolates were correctly identified, resulting in an overall identification performance of 92%. No misidentifications occurred with the two systems. Of the routine isolates one laboratory identified 99/99 (100%) and 90/99 (91%) to species level by Saramis/Axima and conventional...... identification, respectively, whereas the other laboratory identified 83/98 (85%) to species level by both BioTyper/Bruker and conventional identification. Both MALDI-TOF-MS systems are fast, have built-in databases that cover the majority of clinically relevant Candida species, and have an accuracy...

  4. Research on Hybrid Isolation System for Micro-Nano-Fabrication Platform

    Directory of Open Access Journals (Sweden)

    Jie Fu

    2014-06-01

    Full Text Available In order to obtain better vibration suppression effect, this paper designs a semiactive/fully active hybrid isolator by using magnetorheological elastomer (MRE and piezoelectric material. Combined with multimode control scheme, full frequency vibration suppression is achieved. Firstly, series type structure is determined for the hybrid isolator, and the structure of hybrid isolator is designed. Next, the dynamic model of hybrid isolator is derived, the dynamic characteristics measurement for MRE isolator and piezoelectric stack actuator (PSA is established, and parameters such as voltage-displacement coefficient, stiffness and damping constant are identified from the experimental results, respectively. Meanwhile, the switch frequency is determined by experimental results of PSA and MRE isolator. Lastly, influence of the stiffness of MRE, control voltage of PSA, and intermediate mass on hybrid isolator system is analyzed by simulations, and the results show that the hybrid isolator proposed is effective.

  5. Mass spectrometry identification of alkyl-substituted pyrazines produced by Pseudomonas spp. isolates obtained from wine corks.

    Science.gov (United States)

    Bañeras, Lluís; Trias, Rosalia; Godayol, Anna; Cerdán, Laura; Nawrath, Thorben; Schulz, Stefan; Anticó, Enriqueta

    2013-06-15

    We investigated the pyrazine production of 23 Pseudomonas isolates obtained from cork in order to assess their implications in off-flavour development. Off-flavour development in cork stoppers is a crucial process in maintaining the high quality of some wines. Pyrazine production was analyzed by headspace solid-phase-microextraction (HS-SPME) and gas chromatography coupled with mass spectrometry (GC-MS). Five out of the 23 isolates, i.e. Pseudomonas koreensis TCA20, Pseudomonas palleroniana TCA16, Pseudomonas putida TCA23 and N7, and Pseudomonas stutzeri TRA27a were able to produce branched alkyl-substituted pyrazines. For isolates N7 and TCA16, 14 compounds could be identified as pyrazines. The use of mineral media supplemented with different carbon and nitrogen sources resulted in changes in the pyrazine production capacity. In the two strains the amount of pyrazines produced was higher with glucose and decreased significantly with lactate. In all cases, 2,5-di(1-methylethyl)pyrazine was found to be dominant and independent of amino acid addition, suggesting a completely de novo synthesis. Aroma descriptions of most alkyl substituted pyrazines include mild vegetal aromas, not necessarily undesirable for the cork manufacturing industry. Methoxypyrazines, exhibiting earthy and musty aromas, could not be detected in any of the strains analysed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Genotyping of Single Nucleotide Polymorphisms in DNA Isolated from Serum Using Sequenom MassARRAY Technology.

    Directory of Open Access Journals (Sweden)

    Tess V Clendenen

    Full Text Available Large epidemiologic studies have the potential to make valuable contributions to the assessment of gene-environment interactions because they prospectively collected detailed exposure data. Some of these studies, however, have only serum or plasma samples as a low quantity source of DNA.We examined whether DNA isolated from serum can be used to reliably and accurately genotype single nucleotide polymorphisms (SNPs using Sequenom multiplex SNP genotyping technology. We genotyped 81 SNPs using samples from 158 participants in the NYU Women's Health Study. Each participant had DNA from serum and at least one paired DNA sample isolated from a high quality source of DNA, i.e. clots and/or cell precipitates, for comparison.We observed that 60 of the 81 SNPs (74% had high call frequencies (≥95% using DNA from serum, only slightly lower than the 85% of SNPs with high call frequencies in DNA from clots or cell precipitates. Of the 57 SNPs with high call frequencies for serum, clot, and cell precipitate DNA, 54 (95% had highly concordant (>98% genotype calls across all three sample types. High purity was not a critical factor to successful genotyping.Our results suggest that this multiplex SNP genotyping method can be used reliably on DNA from serum in large-scale epidemiologic studies.

  7. 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...

  8. Isolation Mounting for Charge-Coupled Devices

    Science.gov (United States)

    Goss, W. C.; Salomon, P. M.

    1985-01-01

    CCD's suspended by wires under tension. Remote thermoelectric cooling of charge coupled device allows vibration isolating mounting of CCD assembly alone, without having to suspend entire mass and bulk of thermoelectric module. Mounting hardware simple and light. Developed for charge-coupled devices (CCD's) in infrared telescope support adaptable to sensors in variety of environments, e.g., sensors in nuclear reactors, engine exhausts and plasma chambers.

  9. Semi-active control of helicopter vibration using controllable stiffness and damping devices

    Science.gov (United States)

    Anusonti-Inthra, Phuriwat

    , represented by a lumped mass under harmonic force excitation, is supported by a spring and a parallel damper on the fuselage (assumed to have infinite mass). Properties of the spring or damper can then be controlled to reduce transmission of the force into the fuselage or the support structure. This semi-active isolation concept can produce additional 30% vibration reduction beyond the level achieved by a passive isolator. Different control schemes (i.e. open-loop, closed-loop, and closed-loop adaptive schemes) are developed and evaluated to control transmission of vibratory loads to the support structure (fuselage), and it is seen that a closed-loop adaptive controller is required to retain vibration reduction effectiveness when there is a change in operating condition. (Abstract shortened by UMI.)

  10. Evaluation of the structural, electronic, topological and vibrational properties of N-(3,4-dimethoxybenzyl)-hexadecanamide isolated from Maca (Lepidium meyenii) using different spectroscopic techniques

    Science.gov (United States)

    Chain, Fernando; Iramain, Maximiliano Alberto; Grau, Alfredo; Catalán, César A. N.; Brandán, Silvia Antonia

    2017-01-01

    N-(3,4-dimethoxybenzyl)-hexadecanamide (DMH) was characterized by using Fourier Transform infrared (FT-IR) and Raman (FT-Raman), Ultraviolet- Visible (UV-Visible) and Hydrogen and Carbon Nuclear Magnetic Resonance (1H and 13C NMR) spectroscopies. The structural, electronic, topological and vibrational properties were evaluated in gas phase and in n-hexane employing ONIOM and self-consistent force field (SCRF) calculations. The atomic charges, molecular electrostatic potentials, stabilization energies and topological properties of DMH were analyzed and compared with those calculated for N-(3,4-dimethoxybenzyl)-acetamide (DMA) in order to evaluate the effect of the side chain on the properties of DMH. The reactivity and behavior of this alkamide were predicted by using the gap energies and some descriptors. Force fields and the corresponding force constants were reported for DMA only in gas phase and n-hexane due to the high number of vibration normal modes showed by DMH, while the complete vibrational assignments are presented for DMA and both forms of DMH. The comparisons between the experimental FTIR, FT-Raman, UV-Visible and 1H and 13C NMR spectra with the corresponding theoretical ones showed a reasonable concordance.

  11. Isolated human islets require hyperoxia to maintain islet mass, metabolism, and function.

    Science.gov (United States)

    Komatsu, Hirotake; Kang, Dongyang; Medrano, Leonard; Barriga, Alyssa; Mendez, Daniel; Rawson, Jeffrey; Omori, Keiko; Ferreri, Kevin; Tai, Yu-Chong; Kandeel, Fouad; Mullen, Yoko

    2016-02-12

    Pancreatic islet transplantation has been recognized as an effective treatment for Type 1 diabetes; however, there is still plenty of room to improve transplantation efficiency. Because islets are metabolically active they require high oxygen to survive; thus hypoxia after transplant is one of the major causes of graft failure. Knowing the optimal oxygen tension for isolated islets would allow a transplant team to provide the best oxygen environment during pre- and post-transplant periods. To address this issue and begin to establish empirically determined guidelines for islet maintenance, we exposed in vitro cultured islets to different partial oxygen pressures (pO2) and assessed changes in islet volume, viability, metabolism, and function. Human islets were cultured for 7 days in different pO2 media corresponding to hypoxia (90 mmHg), normoxia (160 mmHg), and hyerpoxia (270 or 350 mmHg). Compared to normoxia and hypoxia, hyperoxia alleviated the loss of islet volume, maintaining higher islet viability and metabolism as measured by oxygen consumption and glucose-stimulated insulin secretion responses. We predict that maintaining pre- and post-transplanted islets in a hyperoxic environment will alleviate islet volume loss and maintain islet quality thereby improving transplant outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Pyrolysis-gas chromatography-mass spectrometry of isolated, synthetic and degraded lignins

    Energy Technology Data Exchange (ETDEWEB)

    Saiz-Jimenez, C.; De Leeuw, J.W.

    1984-01-01

    Curie-point pyrolysis-gas chromatography-mass spectrometry was applied to study the chemical structure of sound and fungus degraded, industrial and synthetic lignins. Pyrolysis products reflected in some detail the structural units present in the lignin polymer. Thus, sound spruce lignin yielded trans-isoeugenol coniferaldehyde and trans-coniferyl alcohol as major pyrolysis products. Biodegraded lignin yielded oxidized units, including vanillin, acetoguaiacone, methyl vanillate, propioguaiacone, vanilloyl methyl ketone and vanillic acid as major products. Kraft lignin also showed evidence of oxidation, although not as much as the biodegraded lignin. Major products from this industrial lignin were guaiacol, methylguaiacol, vinylguaiacol and homovanillic acid. Results indicated that synthetic lignin duplicates fairly well the structure of natural lignin. However, coniferylaldehyde and trans-coniferyl alcohol were the dominant products only from the synthetic lignin, indicating the presence of large amounts of coniferyl alcohol and coniferylaldehyde end groups. 21 references.

  13. Micro-/nanosized cantilever beams and mass sensors under applied axial tensile/compressive force vibrating in vacuum and viscous fluid

    Directory of Open Access Journals (Sweden)

    Ivo Stachiv

    2015-11-01

    Full Text Available Vibrating micro-/nanosized cantilever beams under an applied axial force are the key components of various devices used in nanotechnology. In this study, we perform a complete theoretical investigation of the cantilever beams under an arbitrary value of the axial force vibrating in a specific environment such as vacuum, air or viscous fluid. Based on the results easy accessible expressions enabling one the fast and highly accurate estimations of changes in the Q-factor and resonant frequencies of beam oscillating in viscous fluid caused by the applied axial force are derived and analyzed. It has been also shown that for beam-to-string and string vibrational regimes the mode shape starts to significantly deviate from the one known for a beam without axial force. Moreover, a linear dependency of the vibrational amplitude in resonance on the dimensionless tension parameter has been found. We revealed that only a large axial force, i.e. the string vibrational regime, significantly improves the Q-factor of beams submerged in fluid, while an increase of the axial force in beam and beam-to-string transition regimes has a negligibly small impact on the Q-factor enhancement. Experiments carried out on the carbon nanotubes and nanowires are in a good agreement with present theoretical predictions.

  14. 16S-ARDRA and MALDI-TOF mass spectrometry as tools for identification of Lactobacillus bacteria isolated from poultry.

    Science.gov (United States)

    Dec, Marta; Puchalski, Andrzej; Urban-Chmiel, Renata; Wernicki, Andrzej

    2016-06-13

    The objective of our study is to evaluate the potential use of Amplified 16S Ribosomal DNA Restriction Analysis (16S-ARDRA) and MALDI-TOF mass spectrometry (MS) as methods for species identification of Lactobacillus strains in poultry. A total of 80 Lactobacillus strains isolated from the cloaca of chicken, geese and turkeys were identified to the species level by MALDI-TOF MS (on-plate extraction method) and 16S-ARDRA. The two techniques produced comparable classification results, some of which were additionally confirmed by sequencing of 16S rDNA. MALDI-TOF MS enabled rapid species identification but produced more than one reliable identification result for 16.25 % of examined strains (mainly of the species L. johnsonii). For 30 % of isolates intermediate log(scores) of 1.70-1.99 were obtained, indicating correct genus identification but only presumptive species identification. The 16S-ARDRA protocol was based on digestion of 16S rDNA with the restriction enzymes MseI, HinfI, MboI and AluI. This technique was able to distinguish 17 of the 19 Lactobacillus reference species tested and enabled identification of all 80 wild isolates. L. salivarius dominated among the 15 recognized species, followed by L. johnsonii and L. ingluviei. The MALDI-TOF MS and 16S-ARDRA assays are valuable tools for the identification of avian lactobacilli to the species level. MALDI-TOF MS is a fast, simple and cost-effective technique, and despite generating a high percentage of results with a log(score) Lactobacillus bacteria from different habitats.

  15. Evaluation of MALDI-TOF mass spectrometry for differentiation of Pichia kluyveri strains isolated from traditional fermentation processes.

    Science.gov (United States)

    De la Torre González, Francisco Javier; Gutiérrez Avendaño, Daniel Oswaldo; Gschaedler Mathis, Anne Christine; Kirchmayr, Manuel Reinhart

    2018-06-06

    Non- Saccharomyces yeasts are widespread microorganisms and some time ago were considered contaminants in the beverage industry. However, nowadays they have gained importance for their ability to produce aromatic compounds, which in alcoholic beverages improves aromatic complexity and therefore the overall quality. Thus, identification and differentiation of the species involved in fermentation processes is vital and can be classified in traditional methods and techniques based on molecular biology. Traditional methods, however, can be expensive, laborious and/or unable to accurately discriminate on strain level. In the present study, a total of 19 strains of Pichia kluyveri isolated from mezcal, tejuino and cacao fermentations were analyzed with rep-PCR fingerprinting and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The comparative analysis between MS spectra and rep-PCR patterns obtained from these strains showed a high similarity between both methods. However, minimal differences between the obtained rep-PCR and MALDI-TOF MS clusters could be observed. The data shown suggests that MALDI-TOF MS is a promising alternative technique for rapid, reliable and cost-effective differentiation of natives yeast strains isolated from different traditional fermented foods and beverages. This article is protected by copyright. All rights reserved.

  16. Rapid characterisation of Klebsiella oxytoca isolates from contaminated liquid hand soap using mass spectrometry, FTIR and Raman spectroscopy.

    Science.gov (United States)

    Dieckmann, Ralf; Hammerl, Jens Andre; Hahmann, Hartmut; Wicke, Amal; Kleta, Sylvia; Dabrowski, Piotr Wojciech; Nitsche, Andreas; Stämmler, Maren; Al Dahouk, Sascha; Lasch, Peter

    2016-06-23

    Microbiological monitoring of consumer products and the efficiency of early warning systems and outbreak investigations depend on the rapid identification and strain characterisation of pathogens posing risks to the health and safety of consumers. This study evaluates the potential of three rapid analytical techniques for identification and subtyping of bacterial isolates obtained from a liquid hand soap product, which has been recalled and reported through the EU RAPEX system due to its severe bacterial contamination. Ten isolates recovered from two bottles of the product were identified as Klebsiella oxytoca and subtyped using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI TOF MS), near-infrared Fourier transform (NIR FT) Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Comparison of the classification results obtained by these phenotype-based techniques with outcomes of the DNA-based methods pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST) and single nucleotide polymorphism (SNP) analysis of whole-genome sequencing (WGS) data revealed a high level of concordance. In conclusion, a set of analytical techniques might be useful for rapid, reliable and cost-effective microbial typing to ensure safe consumer products and allow source tracking.

  17. The application of "double isolation" in Fourier transform ion cyclotron resonance sustained off-resonance irradiation collisionally-induced dissociation tandem mass spectrometry to remove labile isobaric impurities.

    Science.gov (United States)

    Gates, Paul J; Lopes, Norberto P; Pinto, Emani; Colepicolo, Pio; Cardozo, Karina H M

    2011-01-01

    This study reports the application of "double isolation" in sustained off-resonance irradiation collisionally-induced dissociation tandem mass spectrometry (SORI-CID-MS/MS) to remove radio- frequency (RF) fragment ions of very close mass isobaric ions (0.02 m/z apart). Analyses were performed with a fraction of a biological extract isolated from a macroalgae containing the mycosporine-like amino acid asterina-330. Direct isolation of the precursor ion by narrowing the isolation window proved ineffective as it impinged upon the required ion thus substantially reducing its intensity. By increasing the correlated sweep time, ejection efficiency of the isolation was improved, but caused the unwanted side-effect of RF fragmentation of labile ions. Finally, by skipping the ion activation step and performing a second isolation (in the MS(3) module) the RF fragments from the first isolation were removed leaving a very pure isolation of the required precursor ion and allowed a very clean CID fragmentation. We demonstrated that the m/z 272.1351 ion is derived from the loss of NH(3) from m/z 289.1620 isobaric impurity and is not related to asterina-330. This application represents a powerful tool to remove unwanted ions in the MS/MS spectrum that result from fragmentation of isobaric ions.

  18. Vibrational measurements in 3-ID-B

    International Nuclear Information System (INIS)

    Sutter, J.; Alp, E.; Barraza, J.; Shu, D.

    1998-04-01

    The authors have undertaken a series of vibrational measurements in hutch 3-ID-B. Their motivation was to compare two different methods of mounting an interferometer for effectiveness in vibrational isolation and stability. In addition they were able to compare the stability of the optical table with and without its eight large bolts inserted

  19. Fatty Acid Profiling of Lipid A Isolated from Indigenous salmonella typhi strain by gas chromatography mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Jabbar, A.; Ali, A.; Tawab, A.; Haque, A.; Iqbal, M. [National Inst. for Biotechnology and Genetic Engineering, Faisalabad (Pakistan)

    2014-02-15

    Typhoid, caused by Salmonella enterica serovar Typhi (S. Typhi), is a major health problem worldwide especially in developing countries. Lipopolysaccharides are one of the main virulence factors of S. Typhi. Hydrophobic lipid A anchors the lipopolysaccharides into the bacterial outer membrane and also serves as the epicenter of endotoxicity, which is linked to the presence of several fatty acid chains. Fatty acid profiling is, therefore, very important to understand the endotoxicity of these pathogenic bacteria. To profile lipid A with respect to its fatty acid constituents, a S. Typhi was isolated from blood culture of a typhoid patient from the Faisalabad region of Pakistan. After its complete identification using biochemical and molecular techniques, this bacterium was cultivated in a fermentor. The cell pellet obtained was subjected to hot phenol process to extract and purify lipopolysaccharides. Acid hydrolysis of the lipopolysaccharides yielded lipid A, which was subjected to analyses using GC-MS after derivatization into their fatty acid methyl esters. The fatty acid methyl esters were identified on the basis of their retention times, compared with standards as well as characteristic mass fragmentation patterns of their respective mass spectra. This fatty acid profiling revealed the occurrence of dodecanoic acid (C12:0), tetradecanoic acid (C14:0), 3-hydroxy tetradecanoic acid (3-OH C14:0) and hexadecanoic acid (C16:0) in the lipid A component of S. Typhi strain with the relative percentage abundances 8.5%, 12.5%, 55.9% and 23.1%, respectively. (author)

  20. Fatty Acid Profiling of Lipid A Isolated from Indigenous salmonella typhi strain by gas chromatography mass spectrometry

    International Nuclear Information System (INIS)

    Jabbar, A.; Ali, A.; Tawab, A.; Haque, A.; Iqbal, M.

    2014-01-01

    Typhoid, caused by Salmonella enterica serovar Typhi (S. Typhi), is a major health problem worldwide especially in developing countries. Lipopolysaccharides are one of the main virulence factors of S. Typhi. Hydrophobic lipid A anchors the lipopolysaccharides into the bacterial outer membrane and also serves as the epicenter of endotoxicity, which is linked to the presence of several fatty acid chains. Fatty acid profiling is, therefore, very important to understand the endotoxicity of these pathogenic bacteria. To profile lipid A with respect to its fatty acid constituents, a S. Typhi was isolated from blood culture of a typhoid patient from the Faisalabad region of Pakistan. After its complete identification using biochemical and molecular techniques, this bacterium was cultivated in a fermentor. The cell pellet obtained was subjected to hot phenol process to extract and purify lipopolysaccharides. Acid hydrolysis of the lipopolysaccharides yielded lipid A, which was subjected to analyses using GC-MS after derivatization into their fatty acid methyl esters. The fatty acid methyl esters were identified on the basis of their retention times, compared with standards as well as characteristic mass fragmentation patterns of their respective mass spectra. This fatty acid profiling revealed the occurrence of dodecanoic acid (C12:0), tetradecanoic acid (C14:0), 3-hydroxy tetradecanoic acid (3-OH C14:0) and hexadecanoic acid (C16:0) in the lipid A component of S. Typhi strain with the relative percentage abundances 8.5%, 12.5%, 55.9% and 23.1%, respectively. (author)

  1. Towards a Unified View of Inhomogeneous Stellar Winds in Isolated Supergiant Stars and Supergiant High Mass X-Ray Binaries

    Science.gov (United States)

    Martínez-Núñez, Silvia; Kretschmar, Peter; Bozzo, Enrico; Oskinova, Lidia M.; Puls, Joachim; Sidoli, Lara; Sundqvist, Jon Olof; Blay, Pere; Falanga, Maurizio; Fürst, Felix; Gímenez-García, Angel; Kreykenbohm, Ingo; Kühnel, Matthias; Sander, Andreas; Torrejón, José Miguel; Wilms, Jörn

    2017-10-01

    Massive stars, at least ˜10 times more massive than the Sun, have two key properties that make them the main drivers of evolution of star clusters, galaxies, and the Universe as a whole. On the one hand, the outer layers of massive stars are so hot that they produce most of the ionizing ultraviolet radiation of galaxies; in fact, the first massive stars helped to re-ionize the Universe after its Dark Ages. Another important property of massive stars are the strong stellar winds and outflows they produce. This mass loss, and finally the explosion of a massive star as a supernova or a gamma-ray burst, provide a significant input of mechanical and radiative energy into the interstellar space. These two properties together make massive stars one of the most important cosmic engines: they trigger the star formation and enrich the interstellar medium with heavy elements, that ultimately leads to formation of Earth-like rocky planets and the development of complex life. The study of massive star winds is thus a truly multidisciplinary field and has a wide impact on different areas of astronomy. In recent years observational and theoretical evidences have been growing that these winds are not smooth and homogeneous as previously assumed, but rather populated by dense "clumps". The presence of these structures dramatically affects the mass loss rates derived from the study of stellar winds. Clump properties in isolated stars are nowadays inferred mostly through indirect methods (i.e., spectroscopic observations of line profiles in various wavelength regimes, and their analysis based on tailored, inhomogeneous wind models). The limited characterization of the clump physical properties (mass, size) obtained so far have led to large uncertainties in the mass loss rates from massive stars. Such uncertainties limit our understanding of the role of massive star winds in galactic and cosmic evolution. Supergiant high mass X-ray binaries (SgXBs) are among the brightest X

  2. Turbine blade vibration dampening

    Science.gov (United States)

    Cornelius, C.C.; Pytanowski, G.P.; Vendituoli, J.S.

    1997-07-08

    The present turbine wheel assembly increases component life and turbine engine longevity. The combination of the strap and the opening combined with the preestablished area of the outer surface of the opening and the preestablished area of the outer circumferential surface of the strap and the friction between the strap and the opening increases the life and longevity of the turbine wheel assembly. Furthermore, the mass ``M`` or combined mass ``CM`` of the strap or straps and the centrifugal force assist in controlling vibrations and damping characteristics. 5 figs.

  3. Vibrating minds

    CERN Multimedia

    2009-01-01

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

  4. Vibrational spectroscopy

    Science.gov (United States)

    Umesh P. Agarwal; Rajai Atalla

    2010-01-01

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

  5. Two-step ion-exchange chromatographic purification combined with reversed-phase chromatography to isolate C-peptide for mass spectrometric analysis.

    Science.gov (United States)

    Kabytaev, Kuanysh; Durairaj, Anita; Shin, Dmitriy; Rohlfing, Curt L; Connolly, Shawn; Little, Randie R; Stoyanov, Alexander V

    2016-02-01

    A liquid chromatography with mass spectrometry on-line platform that includes the orthogonal techniques of ion exchange and reversed phase chromatography is applied for C-peptide analysis. Additional improvement is achieved by the subsequent application of cation- and anion-exchange purification steps that allow for isolating components that have their isoelectric points in a narrow pH range before final reversed-phase mass spectrometry analysis. The utility of this approach for isolating fractions in the desired "pI window" for profiling complex mixtures is discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Adaptive Piezoelectric Absorber for Active Vibration Control

    Directory of Open Access Journals (Sweden)

    Sven Herold

    2016-02-01

    Full Text Available Passive vibration control solutions are often limited to working reliably at one design point. Especially applied to lightweight structures, which tend to have unwanted vibration, active vibration control approaches can outperform passive solutions. To generate dynamic forces in a narrow frequency band, passive single-degree-of-freedom oscillators are frequently used as vibration absorbers and neutralizers. In order to respond to changes in system properties and/or the frequency of excitation forces, in this work, adaptive vibration compensation by a tunable piezoelectric vibration absorber is investigated. A special design containing piezoelectric stack actuators is used to cover a large tuning range for the natural frequency of the adaptive vibration absorber, while also the utilization as an active dynamic inertial mass actuator for active control concepts is possible, which can help to implement a broadband vibration control system. An analytical model is set up to derive general design rules for the system. An absorber prototype is set up and validated experimentally for both use cases of an adaptive vibration absorber and inertial mass actuator. Finally, the adaptive vibration control system is installed and tested with a basic truss structure in the laboratory, using both the possibility to adjust the properties of the absorber and active control.

  7. Vibration of fuel bundles

    International Nuclear Information System (INIS)

    Chen, S.S.

    1975-06-01

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

  8. Isolated resonator gyroscope with a drive and sense plate

    Science.gov (United States)

    Challoner, A. Dorian (Inventor); Shcheglov, Kirill V. (Inventor)

    2006-01-01

    The present invention discloses a resonator gyroscope comprising a vibrationally isolated resonator including a proof mass, a counterbalancing plate having an extensive planar region, and one or more flexures interconnecting the proof mass and counterbalancing plate. A baseplate is affixed to the resonator by the one or more flexures and sense and drive electrodes are affixed to the baseplate proximate to the extensive planar region of the counterbalancing plate for exciting the resonator and sensing movement of the gyroscope. The isolated resonator transfers substantially no net momentum to the baseplate when the resonator is excited.

  9. Rapid isolation of biomarkers for compound specific radiocarbon dating using high-performance liquid chromatography and flow injection analysis-atmospheric pressure chemical ionisation mass spectrometry

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Smittenberg, R.H.; Hopmans, E.C.; Schouten, S.

    2002-01-01

    Repeated semi-preparative normal-phase HPLC was performed to isolate selected biomarkers from sediment extracts for radiocarbon analysis. Flow injection analysis mass spectrometry was used for rapid analysis of collected fractions to evaluate the separation procedure, taking only 1 min per fraction.

  10. Chemical analysis of isolated cell walls of Gram-positive bacteria and the determination of the cell wall to cell mass ratio.

    NARCIS (Netherlands)

    Wal, van der A.; Norde, W.; Bendinger, B.; Zehnder, A.J.B.; Lyklema, J.

    1997-01-01

    Cell walls of five Gram-positive bacterial strains, including four coryneforms and a Bacillus brevis strain were isolated and subsequently chemically analysed. The wall contribution to the total cell mass is calculated from a comparison of D-Lactate concentrations in hydrolysates of whole cells and

  11. Earthquake response analysis of a base isolated building

    International Nuclear Information System (INIS)

    Mazda, T.; Shiojiri, H.; Sawada, Y.; Harada, O.; Kawai, N.; Ontsuka, S.

    1989-01-01

    Recently, the seismic isolation has become one of the popular methods in the design of important structures or equipments against the earthquakes. However, it is desired to accumulate the demonstration data on reliability of seismically isolated structures and to establish the analysis methods of those structures. Based on the above recognition, the vibration tests of a base isolated building were carried out in Tsukuba Science City. After that, many earthquake records have been obtained at the building. In order to examine the validity of numerical models, earthquake response analyses have been executed by using both lumped mass model, and finite element model

  12. Mechanical design of a pre-isolator for the CLIC final focusing magnets

    CERN Document Server

    Gaddi, A; Ramos, F; Siegrist, N

    2012-01-01

    Due to the very small vertical beam sizes, the final focusing elements at the future CLIC linear collider need to be stable against vibrations to below 0.15 nanometres at frequencies above about 4 Hz. One of the key elements in the strategy to achieve such a stable environment is a passive, heavy pre-isolator. In this report, the results from the dynamic finite element analyses of the proposed design for such a passive preisolator are summarized. Furthermore, the results from a low frequency, heavy mass passive vibration isolation test set-up used to validate the calculations are shown.

  13. Application of Finite Element Based Simulation and Modal Testing Methods to Improve Vehicle Powertrain Idle Vibration

    Directory of Open Access Journals (Sweden)

    Polat Sendur

    2017-01-01

    Full Text Available Current practice of analytical and test methods related to the analysis, testing and improvement of vehicle vibrations is overviewed. The methods are illustrated on the determination and improvement of powertrain induced steering wheel vibration of a heavy commercial truck. More specifically, the transmissibility of powertrain idle vibration to cabin is investigated with respect to powertrain rigid body modes and modal alignment of the steering column/wheel system is considered. It is found out that roll mode of the powertrain is not separated from idle excitation for effective vibration isolation as well as steering wheel column mode is close to the 3rd engine excitation frequency order, which results in high vibration levels. Powertrain roll mode is optimized by tuning the powertrain mount stiffness to improve the performance. Steering column mode is also separated from the 3rd engine excitation frequency by the application of a mass absorber. It is concluded that the use of analytical and test methods to address the complex relation between design parameters and powertrain idle response is effective to optimize the system performance and evaluate the trade-offs in the vehicle design such as vibration performance and weight. Reference Number: www.asrongo.org/doi:4.2017.2.1.10

  14. Análisis de la eficiencia del sistema de aislamiento de vibraciones de grupos electrógenos MAN 18 V48/60 B // Efficiency analysis of vibration isolation system installed on engine generator sets type MAN 18 V48/60 b

    Directory of Open Access Journals (Sweden)

    Evelio Palomino‐Marín

    2011-01-01

    Full Text Available Todo sistema de aislamiento de vibraciones está encaminado en primera instancia a aislarvibraciones como su propio nombre lo indica. En ocasiones es menester que a la máquina no laperturben vibraciones procedentes del entorno, como lo puede ser por ejemplo, el caso de unarectificadora en un taller de mecanizado. Así mismo, en otras ocasiones resulta necesario aislar lamáquina para evitar que las vibraciones producidas por ella misma afecten al entorno. Tal es el casode los grupos electrógenos MAN 18 V48/60 B, cuyos motores de combustión interna responden a undiseño de 18 cilindros en “V” distribuidos en 13 metros de longitud. El sistema de aislamiento deestos motores consta de 14 paquetes de ocho resortes cada uno, incluyendo un amortiguadorviscoso por cada calzo. Se efectuaron mediciones espectrales de vibraciones en cada uno de estoscalzos antivibratorios, sobre y debajo de estos respectivamente y se evaluó la eficiencia de estoscalzos en todo el espectro, determinándose aquellas frecuencias que por determinadas razones noalcanzan los niveles de eficiencia en el aislamiento establecidos a tales efectos. De esta manera, sepresenta una metodología para conducir este análisis.Palabras claves: calzos antivibratorios, aislamiento de vibraciones, grupos electrógenos.___________________________________________________________________AbstractA vibroisolation system has a priority goal which is isolate vibrations. Such vibrations can come fromthe environment and could affect the machine behavior and could affect its technological functionstoo. That’s the case of a machine tool, for instance. However, it is also possible that vibrations comefrom the own machine and in this case the main goal of vibroisolation system is to avoid thatvibrations go to machine foundations. This is the case on which this paper is focused. Twelvevibration isolators with eight springs each one including a viscous damper are mounted asvibroisolation system on

  15. Molecular Structure, Vibrational Spectra, Quantum Chemical Calculations and Photochemistry of Picolinamide and Isonicotinamide Isolated in Cryogenic Inert Matrixes and in the Neat Low-Temperature Solid Phases

    OpenAIRE

    Borba, Ana; Gómez-Zavaglia, Andrea; Fausto, R.

    2007-01-01

    Picolinamide (PA) and isonicotinamide (INA), two structural isomers of pyridinecarboxamide, have been investigated by matrix isolation and low-temperature solid-state infrared spectroscopy, combined with UV (λ > 235 nm) photoexcitation and density functional theory and ab initio (MP2) theoretical studies. In consonance with the theoretical data, both PA and INA were found to exist in a single conformation in cryogenic rare gas matrixes. Comparison between the experimental spectra of the matri...

  16. Use of matrix assisted laser desorption ionisation-time of flight mass spectrometry in a paediatric clinical laboratory for identification of bacteria commonly isolated from cystic fibrosis patients.

    Science.gov (United States)

    Desai, Ankita Patel; Stanley, Theresa; Atuan, Maria; McKey, Jonelle; Lipuma, John J; Rogers, Beverly; Jerris, Robert

    2012-09-01

    Matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS) has been described as a rapid, accurate method for bacterial identification. To investigate the ability of the technique, using the unamended database supplied with the system, to identify bacteria commonly isolated in cystic fibrosis (CF) patients. Organisms commonly isolated from CF patients identified by MALDI-TOF MS were compared to conventional phenotypic and genotypic analyses. For MALDI-TOF MS, the direct colony technique was used routinely with one extraction procedure performed on a mucoid Pseudomonas aeruginosa. For 24 unique CF specimens, workload comparison and time to identification were assessed. Of 464 tested isolates, conventional (phenotypic and genotypic) identification compared to MALDI-TOF MS showed complete genus, species agreement in 92%, with genus agreement in 98%. This included 29 isolates within the Burkholderia cepacia complex. All 29 were correctly identified to the genus level and 24 of these were speciated. Time to identification with 47 bacterial isolates from 24 CF patients showed identification of 85% of isolates by MALDI-TOF MS at 48 h of incubation, compared to only 34% with conventional methods. Using the unamended database supplied with the system, MALDI-TOF MS provides rapid and reliable identification of bacteria isolated from CF specimens. Time to identification studies showed that the use of same day, same method for organism identification will decrease time to result and optimise microbiology workflow.

  17. Low-Vibration Oscillating Compressor

    Science.gov (United States)

    Studer, P. A.

    1984-01-01

    Oscillating compressor momentum compensated: produces little vibration in its supporting structure. Compressure requires no lubrication and virtually free of wear. Compresses working fluids such as helium, nitrogen or chlorfluorocarbons for Stirling-cycle refrigeration or other purposes. Compressor includes two mutually opposed ferromagnetic pistons of same shape and mass. Electromagnetic flux links both pistons, causing magnetic attraction between them.

  18. Rapid isolation of biomarkers for compound specific radiocarbon dating using high-performance liquid chromatography and flow injection analysis-atmospheric pressure chemical ionisation mass spectrometry.

    Science.gov (United States)

    Smittenberg, Rienk H; Hopmans, Ellen C; Schouten, Stefan; Sinninghe Damsté, Jaap S

    2002-11-29

    Repeated semi-preparative normal-phase HPLC was performed to isolate selected biomarkers from sediment extracts for radiocarbon analysis. Flow injection analysis-mass spectrometry was used for rapid analysis of collected fractions to evaluate the separation procedure, taking only 1 min per fraction. In this way 100-1000 microg of glycerol dialkyl glycerol tetraethers, sterol fractions and chlorophyll-derived phytol were isolated from typically 100 g of marine sediment, i.e., in sufficient quantities for radiocarbon analysis, without significant carbon isotopic fractionation or contamination.

  19. [Identification of mycobacteria by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry--using reference strains and clinical isolates of Mycobacterium].

    Science.gov (United States)

    Niitsuma, Katsunao; Saito, Miwako; Koshiba, Shizuko; Kaneko, Michiyo

    2014-05-01

    Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) method is being played an important role for the inspection of clinical microorganism as a rapid and the price reduction. Mass spectra obtained by measuring become points of identification whether the peak pattern match any species mass spectral pattern. We currently use MALDI-TOF MS for rapid and accurate diagnosis of inactivated reference and clinical isolates of Mycobacterium because of the improved pretreatment techniques compared with former inspection methods that pose a higher risk of infection to the operator. The identification matching rate of score value (SV) peak pattern spectra was compared with that of conventional methods such as strain diffusion/amplification. Also, cultures were examined after a fixed number of days. Compared with the initial inspection technique, the pretreatment stage of current MALDI-TOF MS inspection techniques can improve the analysis of inactivated acid-fast bacteria that are often used as inspection criteria strains of clinical isolates. Next, we compared the concordance rate for identification between MALDI-TOF MS and conventional methods such as diffusion/amplification by comparison of peak pattern spectra and evaluated SV spectra to identify differences in the culture media after the retention period. In examination of 158 strains of clinical isolated Mycobacterium tuberculosis complex (MTC), the identification coincidence rate in the genus level in a matching pattern was 99.4%, when the species level was included 94.9%. About 37 strains of nontuberculous mycobacteria (NTM), the identification coincidence rate in the genus level was 94.6%. M. bovis BCG (Tokyo strain) in the reference strain was judged by the matching pattern to be MTC, and it suggested that they are M. tuberculosis and affinity species with high DNA homology. Nontuberculous mycobacterial M. gordonae strain JATA 33-01 shared peak pattern spectra, excluding the

  20. 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...

  1. Effects of solid-medium type on routine identification of bacterial isolates by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Anderson, Neil W; Buchan, Blake W; Riebe, Katherine M; Parsons, Lauren N; Gnacinski, Stacy; Ledeboer, Nathan A

    2012-03-01

    Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a rapid method for the identification of bacteria. Factors that may alter protein profiles, including growth conditions and presence of exogenous substances, could hinder identification. Bacterial isolates identified by conventional methods were grown on various media and identified using the MALDI Biotyper (Bruker Daltonics, Billerica, MA) using a direct smear method and an acid extraction method. Specimens included 23 Pseudomonas isolates grown on blood agar, Pseudocel (CET), and MacConkey agar (MAC); 20 Staphylococcus isolates grown on blood agar, colistin-nalidixic acid agar (CNA), and mannitol salt agar (MSA); and 25 enteric isolates grown on blood agar, xylose lysine deoxycholate agar (XLD), Hektoen enteric agar (HE), salmonella-shigella agar (SS), and MAC. For Pseudomonas spp., the identification rate to genus using the direct method was 83% from blood, 78% from MAC, and 94% from CET. For Staphylococcus isolates, the identification rate to genus using the direct method was 95% from blood, 75% from CNA, and 95% from MSA. For enteric isolates, the identification rate to genus using the direct method was 100% from blood, 100% from MAC, 100% from XLD, 92% from HE, and 87% from SS. Extraction enhanced identification rates. The direct method of MALDI-TOF analysis of bacteria from selective and differential media yields identifications of varied confidence. Notably, Staphylococci spp. from CNA exhibit low identification rates. Extraction enhances identification rates and is recommended for colonies from this medium.

  2. Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry rapid detection of carbapenamase activity in Acinetobacter baumannii isolates

    Directory of Open Access Journals (Sweden)

    Noha Abouseada

    2017-01-01

    Full Text Available Introduction: Carbapenamase-producing Acinetobacter baumannii are an increasing threat in hospitals and Intensive Care Units. Accurate and rapid detection of carbapenamase producers has a great impact on patient improvement and aids in implementation of infection control measures. Aim: In this study, we describe the use of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI TOF MS to identify carbapenamase-producing A. baumannii isolates in up to 3 h. Isolates and Methods: A total of 50 A. baumannii isolates (of which 39 were carabapenamase producers were tested using MALDI TOF MS. Isolates were incubated for 3 h with 0.25 mg/ml up to 2 mg/ml of imipenem (IMP at 37°C. Supernatants were analysed by MALDI TOF to analyse peaks corresponding to IMP (300 Da and an IMP metabolite (254 Da using UltrafleXtreme (Bruker Daltonics, Bremen, Germany. Results: All carbapenamase-producing isolates were evidenced by the disappearance or reduction in intensity of the 300 Da peak of IPM and the appearance of a 254 Da peak of the IPM metabolite. In isolates that did not produce carbapenamase, the IPM 300 Da peak remained intact. Conclusion: MALDI TOF is a promising tool in the field of diagnostic microbiology that has the ability to transfer identification and antimicrobial susceptibility testing time from days to hours.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  4. Adjustable Nonlinear Springs to Improve Efficiency of Vibration Energy Harvesters

    OpenAIRE

    Boisseau, S.; Despesse, G.; Seddik, B. Ahmed

    2012-01-01

    Vibration Energy Harvesting is an emerging technology aimed at turning mechanical energy from vibrations into electricity to power microsystems of the future. Most of present vibration energy harvesters are based on a mass spring structure introducing a resonance phenomenon that allows to increase the output power compared to non-resonant systems, but limits the working frequency bandwidth. Therefore, they are not able to harvest energy when ambient vibrations' frequencies shift. To follow sh...

  5. Top-quark mass measurement in the 2.1 fb-1 tight lepton and isolated track sample using neutrino φ weighting method

    International Nuclear Information System (INIS)

    Artikov, A.; Bellettini, G.; Trovato, M.; Budagov, Yu.; Glagolev, V.; Pukhov, O.; Sisakyan, A.; Suslov, I.; Chlachidze, G.; Chokheli, D.; Velev, G.

    2008-01-01

    We report on a measurement of the top quark mass in the tight lepton and isolated track sample using the neutrino φ weighting method. After applying the selection cuts for the data sample with the integrated luminosity of 2.1 fb -1 236 events were obtained. These events were reconstructed according to the tt bar hypothesis and fitted as a superposition of signal and combined background. For the expected number of background 105.8±12.9 we measure the top quark mass to be M top =167.7±4.2/4.0 (stat.) ±3.1 (syst.) GeV/c 2

  6. Do Scaphoideus titanus (Hemiptera: Cicadellidae) nymphs use vibrational communication?

    Science.gov (United States)

    Chuche, Julien; Thiéry, Denis; Mazzoni, Valerio

    2011-07-01

    Small Auchenorrhyncha use substrate-borne vibrations to communicate. Although this behaviour is well known in adult leafhoppers, so far no studies have been published on nymphs. Here we checked the occurrence of vibrational communication in Scaphoideus titanus (Hemiptera: Cicadellidae) nymphs as a possible explanation of their aggregative distributions on host plants. We studied possible vibratory emissions of isolated and grouped nymphs, as well as their behavioural responses to vibration stimuli that simulated presence of conspecifics, to disturbance noise, white noise and predator spiders. None of our synthetic stimuli or pre-recorded substrate vibrations from nymphs elicited specific vibration responses and only those due to grooming or mechanical contacts of the insect with the leaf were recorded. Thus, S. titanus nymphs showed to not use species-specific vibrations neither for intra- nor interspecific communication and also did not produce alarm vibrations when facing potential predators. We conclude that their aggregative behaviour is independent from a vibrational communication.

  7. 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

  8. Analyzing powers and interference between one- and multi-step processes in (polarized p, t) reactions on medium-mass vibrational nuclei

    International Nuclear Information System (INIS)

    Yagi, K.; Kunori, S.; Aoki, Y.; Nagano, K.; Tagishi, Y.

    1978-01-01

    A neutron-number (N) dependence of analyzing powers A (theta) has been observed for the first time in (polarized p, t) reactions leading to the quadrupole vibrational states (2 1 + ) in 98 Ru, sup(102,108)Pd, 114 Cd, 116 Sn, and sup(120,126)Te. Although analyzing powers for the ground-state transitions A(theta,0 sub(g)sup(+)) are very similar to each other, those for the 2 1 + transitions A(theta,2 1 + ) for the nuclei belonging to the beginning of the N = 50 - 82 shell are markedly different, having almost opposite signs, from A(theta,2 1 + ) for nuclei belonging to the latter half of the major shell. The difference is explained as a result of a sign change of the interference between one- and inelastic multi-step processes in two-neutron pickup reactions. Nuclear structure effects on such an interference are discussed on the basis of the microscopic description of collective quadrupole oscillation of nuclei. (author)

  9. 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.

  10. 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

  11. 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)

  12. Floor Vibrations - as Induced and Reduced by Humans

    DEFF Research Database (Denmark)

    Pedersen, Lars

    . As for dynamic loads focus is placed on heel impact excitation and actions of jumping people causing floor vibrations. As for interaction between stationary humans and the vibrating floor focus is on modelling humans as oscillating spring-mass-damper systems attached to the floor rather than as simple added mass...

  13. Vibrations in force-and-mass disordered alloys in the average local-information transfer approximation. Application to Al-Ag

    International Nuclear Information System (INIS)

    Czachor, A.

    1979-01-01

    The configuration-averaged displacement-displacement Green's function, derived in the locator-based approximation accounting for average transfer of information on local coupling and mass, has been applied to study the force-and-mass-disorder induced modifications of phonon dispersion relations in substitutional alloys of cubic structures. In this approach the translational invariance condition is obeyed whereas damping is neglected. The force-disorder was found to lead to additional splitting of phonon curves besides that due to mass-disorder, even in the small impurity-concentration case; at larger concentrations the number of splits (frequency gaps) should be still greater. The use of a quasi-locator in the Green's function derivation allows one to partly reconcile the present results with those of the average t-matrix approximation. The experimentally observed splitting in the [100]T phonon dispersion curve for Al-Ag alloys has been interpreted in terms of the above theory and of a quasi-mass of heavy impurity atoms. (Author)

  14. Free vibration analysis of elastically supported Timoshenko columns ...

    Indian Academy of Sciences (India)

    , concen- trated mass ... linear equations of motion for transverse vibrations of a simply supported beam carrying con- centrated ... a cantilever Timoshenko beam with a rigid tip mass. Ferreira .... Figure 3. Free body diagram of elastic support.

  15. PRODUCTION OF EMBBRYONIC STEM CELLS FROM INNER CELL MASS OF BLASTOCYST ISOLATED BY ENZYMATIC AND IMMUNOSURGERY METHODS

    Directory of Open Access Journals (Sweden)

    Thomas Mata Hine

    2008-03-01

    Full Text Available The objective of the research is determining the ICM isolation method to produce ESC. Blastocyst stage of DDy mice embryos were used in this study. Zona pellucida of blastocysts were removed by 0.25% pronase, the ICM isolation were done by enzimatic or immunosurgery method, and then they were cultured in DMEM-high glucose supplemented with mercaptoethanol, gentamycin, fetal bovine serum, and cumulus cells as feeder layer. The result of the research indicated that immunosurgery method yielding attachment rate and number ESC colony 93.85% and 43.08%, respectively, higher (P<0.05 than enzimatic method that weree 79.63% and 18.52%, respectively, but the viability of ICM cells were equal (P >0.05 that are 93.59% in enzymatic method and 98.56% in immunosurgery method. This research concluded that immunosurgery more effective method for isolation of ICM and ESC production than enzymatic method.

  16. [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.

  17. DETECTION, ISOLATION, AND IDENTIFICATION OF TRUXILLINES IN ILLICIT COCAINE BY MEANS OF THIN-LAYER CHROMATOGRAPHY AND MASS-SPECTROMETRY

    NARCIS (Netherlands)

    ENSING, JG; DEZEEUW, RA

    By means of thin-layer chromatography, an unidentified alkaloidal fraction was observed in illicit cocaine. Because of its persisting presence, efforts were undertaken to isolate and identify this fraction. Various analytical techniques showed complex results, finally pointing to the possibility of

  18. Top quark mass measurement in the 2.9 fb-1 tight lepton and isolated track sample using neutrinoφ weighting method

    International Nuclear Information System (INIS)

    Bellettini, G.; Trovato, M.; Budagov, Yu.; Glagolev, V.; Sisakyan, A.; Suslov, I.; Chlachidze, G.; Velev, G.

    2008-01-01

    We report on a measurement of the top quark mass with tt bar dilepton events produced in pp bar collisions at the Fermilab Tevatron (√s 1.96 TeV) and collected by the CDF II detector. Events with a a charged muon or electron and an isolated track are searched for tt bar candidates. A sample of 328 events, corresponding to an integrated luminosity of 2.9 fb -1 , is obtained after all selection cuts. The top quark mass is reconstructed by minimizing a χ 2 function in the assumption of the tt bar dilepton hypothesis. The unconstrained kinematics of dilepton events is taken into account by the scan over the space of possibilities for the azimuthal angles of neutrinos, and a preferred mass is built for each event. In order to extract the top quark mass, a likelihood fit of the preferred mass distribution in data to a weighted sum of signal and background probability density functions is performed. Using the background constrained fit with 145.0±17.3 events expected from background we measure m t = 165.5 ± 3.3 3.4 (stat.) GeV/c 2 . The estimate of systematic error is 3.1 GeV/c 2

  19. Affinity isolation and I-DIRT mass spectrometric analysis of the Escherichia coli O157:H7 Sakai RNA polymerase complex.

    Science.gov (United States)

    Lee, David J; Busby, Stephen J W; Westblade, Lars F; Chait, Brian T

    2008-02-01

    Bacteria contain a single multisubunit RNA polymerase that is responsible for the synthesis of all RNA. Previous studies of the Escherichia coli K-12 laboratory strain identified a group of effector proteins that interact directly with RNA polymerase to modulate the efficiency of transcription initiation, elongation, or termination. Here we used a rapid affinity isolation technique to isolate RNA polymerase from the pathogenic Escherichia coli strain O157:H7 Sakai. We analyzed the RNA polymerase enzyme complex using mass spectrometry and identified associated proteins. Although E. coli O157:H7 Sakai contains more than 1,600 genes not present in the K-12 strain, many of which are predicted to be involved in transcription regulation, all of the identified proteins in this study were encoded on the "core" E. coli genome.

  20. Affinity Isolation and I-DIRT Mass Spectrometric Analysis of the Escherichia coli O157:H7 Sakai RNA Polymerase Complex▿

    Science.gov (United States)

    Lee, David J.; Busby, Stephen J. W.; Westblade, Lars F.; Chait, Brian T.

    2008-01-01

    Bacteria contain a single multisubunit RNA polymerase that is responsible for the synthesis of all RNA. Previous studies of the Escherichia coli K-12 laboratory strain identified a group of effector proteins that interact directly with RNA polymerase to modulate the efficiency of transcription initiation, elongation, or termination. Here we used a rapid affinity isolation technique to isolate RNA polymerase from the pathogenic Escherichia coli strain O157:H7 Sakai. We analyzed the RNA polymerase enzyme complex using mass spectrometry and identified associated proteins. Although E. coli O157:H7 Sakai contains more than 1,600 genes not present in the K-12 strain, many of which are predicted to be involved in transcription regulation, all of the identified proteins in this study were encoded on the “core” E. coli genome. PMID:18083804

  1. Vibration of liquid-filled thin shells

    International Nuclear Information System (INIS)

    Kalnins, A.

    1979-01-01

    This paper describes the analysis of free and forced vibration of a thin, axisymmetric shell, which contains some liquid. The axis of symmetry is vertical. Only such vibration is considered which can be produced by a horizontal movement of the base of shell. The objective of this paper is to examine the response of the coupled shell-liquid system for a frequency range lying between zero and the lowest natural sloshing frequency of the liquid. The mass of the liquid is modeled by a stationary and one or more sloshing masses. It is shown how the stationary mass can be incorporated in the vibration analysis of the shell and how to natural frequency of the coupled shell-liquid system can be obtained from a simple formula, if the lowest natural frequency of the shell, plus the stationary mass of the liquid, can be determined. A numerical example is given. (orig.)

  2. Application of system concept in vibration and noise reduction

    Directory of Open Access Journals (Sweden)

    SHENG Meiping

    2017-08-01

    Full Text Available Although certain vibration and noise control technologies are maturing, such as vibration absorption, vibration isolation, sound absorption and sound insulation, and new methods for specific frequency bands or special environments have been proposed unceasingly, there is still no guarantee that practical effective vibration and noise reduction can be obtained. An important constraint for vibration and noise reduction is the lack of a system concept, and the integrity and relevance of such practical systems as ship structure have not obtained enough attention. We have tried to use the system engineering theory in guiding vibration and noise reduction, and have already achieved certain effects. Based on the system concept, the noise control of a petroleum pipeline production workshop has been completed satisfactorily, and the abnormal noise source identification of an airplane has been accomplished successfully. We want to share our experience and suggestions to promote the popularization of the system engineering theory in vibration and noise control.

  3. 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.

  4. Isolation and identification of phytoestrogens and flavonoids in an Ayurvedic proprietary medicine using chromatographic and Mass Spectroscopic analysis

    Institute of Scientific and Technical Information of China (English)

    Sulaiman CT; Arun A; Anandan EM; Sandhya CR; Indira Balachandran

    2015-01-01

    Objective: To develop analytical methods for the isolation and structural identification of poly phenols including phytoestrogens in Mensokot tablet, a herbal proprietary medicine. Methods:Isolation consisted of an ultrasound-assisted extraction, followed by acid hydrolysis and a final liquid-liquid extraction step in diethyl ether. Identification and structural characterisation was done by liquid chromatography coupled with Q-TOF-ESI-MS/MS analysis. Results:Phytoestrogens such as Coumestrol, Genistein and Glycitein have been identified in Mensokot tablet along with several other flavonoids. Conclusion: In the present research, a rapid HPLC-MS/MS method has been developed for the identification of phytoestrogens and other flavonoids from an Ayurvedic proprietary medicine. Phytoestrogens are considered to play an important role in the prevention of cancers, heart disease, menopausal symptoms and osteoporosis.

  5. ESM vibration dampers: the intelligent way to take care of components; ESM Schwingungsdaempfer: Bauteile intelligent geschont

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2007-07-01

    Three-Point Suspension: In wind turbines with stall and pitch systems of every size the three-point suspension with clamping bushings of ESM is very common. It is the task of the vibration isolation to suspend the gearbox elastically on the main frame at two mounting points. Four-Point Suspension: Particularly in wind turbines of the multi-megawatt-class the four-point suspension is a more and more spreading system. The rotor shaft is supported by one bearing which is able to take the yaw and nodding torques or by two rotor shaft bearings. So all the torques except the driving torque are directly transferred to the main frame by the rotor shaft support. The gearbox has only one degree of freedom left. To avoid horizontal constraint forces on the gearbox with the four-point suspension normally multi-sandwich mounts or a pendulum support is used as both have a very low horizontal stiffness. One problem persists anyway: Due to assembly tolerances and main frame deformations because of nodding torques the gearbox has to withstand huge vertical constriant forces. Especially for wind turbines with four-point suspension ESM has developed a hydraulic gearbox support. Generator Suspension: In wind turbines with a gearbox and a fast running generator the generator is mounted to the main frame with normally four elastomeric generator mounts. Tuned Mass Dampers: Tuned mass dampers are used to reduce single tone vibrations in machines, buildings and other facilities. The function of a tuned mass damper is based on an oscillating mass which moves contrary to the spurious vibration and reduces it thereby. ESM has developed easy adjustable tuned mass dampers, which may be installed to a wind turbine easily if a wind turbine has problems with single tone vibrations. (orig.)

  6. 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.

  7. Seismic isolation structure for pool-type LMFBR - isolation building with vertically isolated floor for NSSS

    International Nuclear Information System (INIS)

    Sakurai, A.; Shiojiri, H.; Aoyagi, S.; Matsuda, T.; Fujimoto, S.; Sasaki, Y.; Hirayama, H.

    1987-01-01

    The NSSS isolation floor vibration characteristics were made clear. Especially, the side support bearing (rubber bearing) is effective for horizontal floor motion restraint and rocking motion control. Seismic isolation effects for responses of the reactor components can be sufficiently expected, using the vertical seismic isolation floor. From the analytical and experimental studies, the following has been concluded: (1) Seismic isolation structure, which is suitable for large pool-type LMFBR, were proposed. (2) Seismic response characteristics of the seismic isolation structure were investigated. It was made clear that the proposed seismic isolation (Combination of the isolated building and the isolated NSSS floor) was effective. (orig./HP)

  8. 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-.

  9. Shock and vibration technology with applications to electrical systems

    Science.gov (United States)

    Eshleman, R. L.

    1972-01-01

    A survey is presented of shock and vibration technology for electrical systems developed by the aerospace programs. The shock environment is surveyed along with new techniques for modeling, computer simulation, damping, and response analysis. Design techniques based on the use of analog computers, shock spectra, optimization, and nonlinear isolation are discussed. Shock mounting of rotors for performance and survival, and vibration isolation techniques are reviewed.

  10. ANALYSIS OF VIBRATORY PROTECTION SYSTEM VIBRATION DURING HARMONIC AND POLYHARMONIC EXCITATIONS

    Directory of Open Access Journals (Sweden)

    T. N. Mikulik

    2011-01-01

    Full Text Available The paper considers a mathematical model of local «driver-seat» system and an algorithm for vibratory loading formation at external actions. Results of the investigations on the system vibration according to minimum vibration acceleration depending on transfer force factor acting on the seat and a vibration isolation factor are presented in the paper.

  11. Mass Spectrometry-Based Metabolomics of Agave Sap (Agave salmiana after Its Inoculation with Microorganisms Isolated from Agave Sap Concentrate Selected to Enhance Anticancer Activity

    Directory of Open Access Journals (Sweden)

    Luis M. Figueroa

    2017-11-01

    Full Text Available Saponins have been correlated with the reduction of cancer cell growth and the apoptotic effect of agave sap concentrate. Empirical observations of this artisanal Mexican food have shown that fermentation occurs after agave sap is concentrated, but little is known about the microorganisms that survive after cooking, or their effects on saponins and other metabolites. The aim of this study was to evaluate the changes in metabolites found in agave (A. salmiana sap after its fermentation with microorganisms isolated from agave sap concentrate, and demonstrate its potential use to enhance anticancer activity. Microorganisms were isolated by dilution plating and identified by 16S rRNA analysis. Isolates were used to ferment agave sap, and their corresponding butanolic extracts were compared with those that enhanced the cytotoxic activity on colon (Caco-2 and liver (Hep-G2 cancer cells. Metabolite changes were investigated by mass spectrometry-based metabolomics. Among 69 isolated microorganisms, the actinomycetes Arthrobacter globiformis and Gordonia sp. were used to analyze the metabolites, along with bioactivity changes. From the 939 ions that were mainly responsible for variation among fermented samples at 48 h, 96 h, and 192 h, four were correlated to anticancer activity. It was shown that magueyoside B, a kammogenin glycoside, was found at higher intensities in the samples fermented with Gordonia sp. that reduced Hep-G2 viability better than controls. These findings showed that microorganisms from agave sap concentrate change agave sap metabolites such as saponins. Butanolic extracts obtained after agave sap fermentation with Arthrobacter globiformis or Gordonia sp. increased the cancer cell growth inhibitory effect on colon or liver cancer cells, respectively.

  12. Effect of low-frequency vibrations on speckle interferometry fringes

    International Nuclear Information System (INIS)

    Vikram, C.S.; Pechersky, M.J.

    1998-01-01

    The effects of low-frequency vibrations on speckle correlation fringes have been investigated. The relatively short capture time of the camera in the low-frequency case may yield usable fringe contrast in spite of vibration. It has been shown that the fringes also shift due to the vibration. The study is in agreement with experimental observations of good-contrast correlation fringes even if the object is not on a vibration-isolated table. Some such experimental observations are also presented. copyright 1998 Society of Photo-Optical Instrumentation Engineers

  13. Identification of clinical isolates of Aspergillus, including cryptic species, by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).

    Science.gov (United States)

    Vidal-Acuña, M Reyes; Ruiz-Pérez de Pipaón, Maite; Torres-Sánchez, María José; Aznar, Javier

    2017-12-08

    An expanded library of matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been constructed using the spectra generated from 42 clinical isolates and 11 reference strains, including 23 different species from 8 sections (16 cryptic plus 7 noncryptic species). Out of a total of 379 strains of Aspergillus isolated from clinical samples, 179 strains were selected to be identified by sequencing of beta-tubulin or calmodulin genes. Protein spectra of 53 strains, cultured in liquid medium, were used to construct an in-house reference database in the MALDI-TOF MS. One hundred ninety strains (179 clinical isolates previously identified by sequencing and the 11 reference strains), cultured on solid medium, were blindy analyzed by the MALDI-TOF MS technology to validate the generated in-house reference database. A 100% correlation was obtained with both identification methods, gene sequencing and MALDI-TOF MS, and no discordant identification was obtained. The HUVR database provided species level (score of ≥2.0) identification in 165 isolates (86.84%) and for the remaining 25 (13.16%) a genus level identification (score between 1.7 and 2.0) was obtained. The routine MALDI-TOF MS analysis with the new database, was then challenged with 200 Aspergillus clinical isolates grown on solid medium in a prospective evaluation. A species identification was obtained in 191 strains (95.5%), and only nine strains (4.5%) could not be identified at the species level. Among the 200 strains, A. tubingensis was the only cryptic species identified. We demonstrated the feasibility and usefulness of the new HUVR database in MALDI-TOF MS by the use of a standardized procedure for the identification of Aspergillus clinical isolates, including cryptic species, grown either on solid or liquid media. © The Author 2017. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For

  14. 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...

  15. 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.

  16. Evaluating Attenuation of Vibration Response using Particle Impact Damping for a Range of Equipment Assemblies

    Science.gov (United States)

    Knight, Brent; Parsons, David; Smith, Andrew; Hunt, Ron; LaVerde, Bruce; Towner, Robert; Craigmyle, Ben

    2013-01-01

    Particle dampers provide a mechanism for diverting energy away from resonant structural vibrations. This experimental study provides data from a series of acoustically excited tests to determine the effectiveness of these dampers for equipment mounted to a curved orthogrid panel for a launch vehicle application. Vibration attenuation trends are examined for variations in particle damper fill level, component mass, and excitation energy. A significant response reduction at the component level was achieved, suggesting that comparatively small, strategically placed, particle damper devices might be advantageously used in launch vehicle design. These test results were compared to baseline acoustic response tests without particle damping devices, over a range of isolation and damping parameters. Instrumentation consisting of accelerometers, microphones, and still photography data will be collected to correlate with the analytical results.

  17. 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.

  18. Vibration of imperfect rotating disk

    Directory of Open Access Journals (Sweden)

    Půst L.

    2011-12-01

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

  19. Application of Digital Image Analysis to Determine Pancreatic Islet Mass and Purity in Clinical Islet Isolation and Transplantation

    Science.gov (United States)

    Wang, Ling-jia; Kissler, Hermann J; Wang, Xiaojun; Cochet, Olivia; Krzystyniak, Adam; Misawa, Ryosuke; Golab, Karolina; Tibudan, Martin; Grzanka, Jakub; Savari, Omid; Grose, Randall; Kaufman, Dixon B; Millis, Michael; Witkowski, Piotr

    2015-01-01

    Pancreatic islet mass, represented by islet equivalent (IEQ), is the most important parameter in decision making for clinical islet transplantation. To obtain IEQ, the sample of islets is routinely counted manually under a microscope and discarded thereafter. Islet purity, another parameter in islet processing, is routinely acquired by estimation only. In this study, we validated our digital image analysis (DIA) system developed using the software of Image Pro Plus for islet mass and purity assessment. Application of the DIA allows to better comply with current good manufacturing practice (cGMP) standards. Human islet samples were captured as calibrated digital images for the permanent record. Five trained technicians participated in determination of IEQ and purity by manual counting method and DIA. IEQ count showed statistically significant correlations between the manual method and DIA in all sample comparisons (r >0.819 and p islet particle number (IPN) and the IEQ/IPN ratio did not differ statistically between manual counting method and DIA. In conclusion, the DIA used in this study is a reliable technique in determination of IEQ and purity. Islet sample preserved as a digital image and results produced by DIA can be permanently stored for verification, technical training and islet information exchange between different islet centers. Therefore, DIA complies better with cGMP requirements than the manual counting method. We propose DIA as a quality control tool to supplement the established standard manual method for islets counting and purity estimation. PMID:24806436

  20. Proposal to use vibration analysis steering components and car body to monitor, for example, the state of unbalance wheel

    Science.gov (United States)

    Janczur, R.

    2016-09-01

    The results of road tests of car VW Passat equipped with tires of size 195/65 R15, on the influence of the unbalancing front wheel on vibration of the parts of steering system, steering wheel and the body of the vehicle have been presented in this paper. Unbalances wheels made using weights of different masses, placed close to the outer edge of the steel rim and checked on the machine Hunter GSP 9700 for balancing wheels. The recorded waveforms vibration steering components and car body, at different constant driving speeds, subjected to spectral analysis to determine the possibility of isolating vibration caused by unbalanced wheel in various states and coming from good quality asphalt road surface. The results were discussed in terms of the possibility of identifying the state of unbalancing wheels and possible changes in radial stiffness of the tire vibration transmitted through the system driving wheel on the steering wheel. Vibration analysis steering components and car body, also in the longitudinal direction, including information from the CAN bus of the state of motion of the car, can be used to monitor the development of the state of unbalance wheel, tire damage or errors shape of brake discs or brake drums, causing pulsations braking forces.

  1. Interfacial instabilities in vibrated fluids

    Science.gov (United States)

    Porter, Jeff; Laverón-Simavilla, Ana; Tinao Perez-Miravete, Ignacio; Fernandez Fraile, Jose Javier

    2016-07-01

    Vibrations induce a range of different interfacial phenomena in fluid systems depending on the frequency and orientation of the forcing. With gravity, (large) interfaces are approximately flat and there is a qualitative difference between vertical and horizontal forcing. Sufficient vertical forcing produces subharmonic standing waves (Faraday waves) that extend over the whole interface. Horizontal forcing can excite both localized and extended interfacial phenomena. The vibrating solid boundaries act as wavemakers to excite traveling waves (or sloshing modes at low frequencies) but they also drive evanescent bulk modes whose oscillatory pressure gradient can parametrically excite subharmonic surface waves like cross-waves. Depending on the magnitude of the damping and the aspect ratio of the container, these locally generated surfaces waves may interact in the interior resulting in temporal modulation and other complex dynamics. In the case where the interface separates two fluids of different density in, for example, a rectangular container, the mass transfer due to vertical motion near the endwalls requires a counterflow in the interior region that can lead to a Kelvin-Helmholtz type instability and a ``frozen wave" pattern. In microgravity, the dominance of surface forces favors non-flat equilibrium configurations and the distinction between vertical and horizontal applied forcing can be lost. Hysteresis and multiplicity of solutions are more common, especially in non-wetting systems where disconnected (partial) volumes of fluid can be established. Furthermore, the vibrational field contributes a dynamic pressure term that competes with surface tension to select the (time averaged) shape of the surface. These new (quasi-static) surface configurations, known as vibroequilibria, can differ substantially from the hydrostatic state. There is a tendency for the interface to orient perpendicular to the vibrational axis and, in some cases, a bulge or cavity is induced

  2. On-line two-dimensional capillary electrophoresis with mass spectrometric detection using a fully electric isolated mechanical valve.

    Science.gov (United States)

    Kohl, Felix J; Montealegre, Cristina; Neusüß, Christian

    2016-04-01

    CE is becoming more and more important in many fields of bioanalytical chemistry. Besides optical detection, hyphenation to ESI-MS detection is increasingly applied for sensitive identification purposes. Unfortunately, many CE techniques and methods established in research and industry are not compatible to ESI-MS since essential components of the background electrolyte interfere in ES ionization. In order to identify unknown peaks in established CE methods, here, a heart-cut 2D-CE separation system is introduced using a fully isolated mechanical valve with an internal loop of only 20 nL. In this system, the sample is separated using potentially any non-ESI compatible method in the first separation dimension. Subsequently, the portion of interest is cut by the internal sample loop of the valve and reintroduced to the second dimension where the interfering compounds are removed, followed by ESI-MS detection. When comparing the separation efficiency of the system with the valve to a system using a continuous capillary only a slight increase in peak width is observed. Ultraviolet/visible detection is integrated in the first dimension for switching time determination, enabling reproducible cutting of peaks of interest. The feasibility of the system is successfully demonstrated by a 2D analysis of a BSA tryptic digest sample using a nonvolatile (phosphate based) background electrolyte in the first dimension. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. 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.

  4. 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.)

  5. 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)

  6. Quantitative comparison of structure and dynamics of elastin following three isolation schemes by 13C solid state NMR and MALDI mass spectrometry.

    Science.gov (United States)

    Papaioannou, A; Louis, M; Dhital, B; Ho, H P; Chang, E J; Boutis, G S

    2015-05-01

    Methods for isolating elastin from fat, collagen, and muscle, commonly used in the design of artificial elastin based biomaterials, rely on exposing tissue to harsh pH levels and temperatures that usually denature many proteins. At present, a quantitative measurement of the modifications to elastin following isolation from other extracellular matrix constituents has not been reported. Using magic angle spinning (13)C NMR spectroscopy and relaxation methodologies, we have measured the modification in structure and dynamics following three known purification protocols. Our experimental data reveal that the (13)C spectra of the hydrated samples appear remarkably similar across the various purification methods. Subtle differences in the half maximum widths were observed in the backbone carbonyl suggesting possible structural heterogeneity across the different methods of purification. Additionally, small differences in the relative signal intensities were observed between purified samples. Lyophilizing the samples results in a reduction of backbone motion and reveals additional differences across the purification methods studied. These differences were most notable in the alanine motifs indicating possible changes in cross-linking or structural rigidity. The measured correlation times of glycine and proline moieties are observed to also vary considerably across the different purification methods, which may be related to peptide bond cleavage. Lastly, the relative concentration of desmosine cross-links in the samples quantified by MALDI mass spectrometry is reported. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Comparison of dialysis and solid-phase extraction for isolation and concentration of dissolved organic matter prior to Fourier transform ion cyclotron resonance mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tfaily, Malak M.; Cooper, William T. [Florida State University, Department of Chemistry and Biochemistry, Tallahassee, FL (United States); Hodgkins, Suzanne; Chanton, Jeffrey P. [Florida State University, Department of Earth, Ocean and Atmospheric Science, Tallahassee, FL (United States); Podgorski, David C. [Florida State University, Department of Chemistry and Biochemistry, Tallahassee, FL (United States); Florida State University, National High Magnetic Field Laboratory, Tallahassee, FL (United States)

    2012-08-15

    We compare two methods, solid-phase extraction (SPE) and dialysis, commonly used for extraction and concentration of dissolved organic matter (DOM) prior to molecular characterization by electrospray ionization (ESI) and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry. Spectra of DOM samples from Minnesota and Sweden peatlands that were extracted with styrene divinyl benzene polymer SPE sorbents included ions with formulas that had higher oxygen to carbon (O/C) ratios than spectra of DOM from the same samples after de-salting by dialysis. The SPE method was not very effective in extracting several major classes of DOM compounds that had high ESI efficiencies, including carboxylic acids and organo-sulfur compounds, and that out-competed other less-functionalized compounds (e.g., carbohydrates) for charge in the ESI source. The large abundance of carboxylic acids in the dialysisextracted DOM, likely the result of in situ microbial production, makes it difficult to see other (mainly hydrophilic) compounds with high O/C ratios. Our results indicate that, while dialysis is generally preferable for the isolation of DOM, for samples with high microbial inputs, the use of both isolation methods is recommended for a more accurate molecular representation. (orig.)

  8. Transfer vibration through spine

    OpenAIRE

    Benyovszky, Adam

    2012-01-01

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

  9. Comparative studies of perceived vibration strength for commercial mobile phones.

    Science.gov (United States)

    Lee, Heow Pueh; Lim, Siak Piang

    2014-05-01

    A mobile phone, also known as cell phone or hand phone, is among the most popular electrical devices used by people all over the world. The present study examines the vibration perception of mobile phones by co-relating the relevant design parameters such as excitation frequency, and size and mass of mobile phones to the vibration perception survey by volunteers. Five popular commercially available mobile phone models were tested. The main findings for the perception surveys were that higher vibration frequency and amplitude of the peak acceleration would result in stronger vibration perception of the mobile phones. A larger contact surface area with the palms and figures, higher peak acceleration and the associated larger peak inertia force may be the main factors for the relatively higher vibration perception. The future design for the vibration alert of the mobile phones is likely to follow this trend. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  10. 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

  11. Vibration Based Sun Gear Damage Detection

    Science.gov (United States)

    Hood, Adrian; LaBerge, Kelsen; Lewicki, David; Pines, Darryll

    2013-01-01

    Seeded fault experiments were conducted on the planetary stage of an OH-58C helicopter transmission. Two vibration based methods are discussed that isolate the dynamics of the sun gear from that of the planet gears, bearings, input spiral bevel stage, and other components in and around the gearbox. Three damaged sun gears: two spalled and one cracked, serve as the focus of this current work. A non-sequential vibration separation algorithm was developed and the resulting signals analyzed. The second method uses only the time synchronously averaged data but takes advantage of the signal/source mapping required for vibration separation. Both algorithms were successful in identifying the spall damage. Sun gear damage was confirmed by the presence of sun mesh groups. The sun tooth crack condition was inconclusive.

  12. Hydroelastic Vibrations of Ships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Folsø, Rasmus

    2002-01-01

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

  13. 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

  14. Gearbox vibration diagnostic analyzer

    Science.gov (United States)

    1992-01-01

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

  15. 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.

  16. 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.

  17. 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...

  18. Effect of distributive mass of spring on power flow in engineering test

    Science.gov (United States)

    Sheng, Meiping; Wang, Ting; Wang, Minqing; Wang, Xiao; Zhao, Xuan

    2018-06-01

    Mass of spring is always neglected in theoretical and simulative analysis, while it may be a significance in practical engineering. This paper is concerned with the distributive mass of a steel spring which is used as an isolator to simulate isolation performance of a water pipe in a heating system. Theoretical derivation of distributive mass effect of steel spring on vibration is presented, and multiple eigenfrequencies are obtained, which manifest that distributive mass results in extra modes and complex impedance properties. Furthermore, numerical simulation visually shows several anti-resonances of the steel spring corresponding to impedance and power flow curves. When anti-resonances emerge, the spring collects large energy which may cause damage and unexpected consequences in practical engineering and needs to be avoided. Finally, experimental tests are conducted and results show consistency with that of the simulation of the spring with distributive mass.

  19. Variable stiffness and damping MR isolator

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X Z; Wang, X Y; Li, W H; Kostidis, K [University of Wollongong, School of Mechanical, Materials and Mechatronic Engineering, NSW 2522 (Australia)], E-mail: weihuali@uow.edu.au

    2009-02-01

    This paper presents the development of a magnetorheological (MR) fluid-based variable stiffness and damping isolator for vibration suppressions. The MR fluid isolator used a sole MR control unit to achieve the variable stiffness and damping in stepless and relative large scope. A mathematical model of the isolator was derived, and a prototype of the MR fluid isolator was fabricated and its dynamic behavior was measured in vibration under various applied magnetic fields. The parameters of the model under various magnetic fields were identified and the dynamic performances of isolator were evaluated.

  20. Determination of vibrational parameters of methanol from matrix-isolation infrared spectroscopy and ab initio calculations. Part 1 - Spectral analysis in the domain 11 000-200 cm{sup -1}

    Energy Technology Data Exchange (ETDEWEB)

    Perchard, J.P. [Universite Pierre et Marie Curie, CNRS, Laboratoire de Dynamique, Interactions et Reactivite, UMR 7075, Case 49, 4 Place Jussieu, 75252 Paris (France)], E-mail: jpp@spmol.jussieu.fr; Romain, F. [Universite Pierre et Marie Curie, CNRS, Laboratoire de Dynamique, Interactions et Reactivite, UMR 7075, Case 49, 4 Place Jussieu, 75252 Paris (France); Bouteiller, Y. [Universite Paris-Nord, CNRS, Laboratoire de Physique des Lasers, UMR 7538, 93430 Villetaneuse (France)

    2008-01-22

    Infrared spectra of three isotopic species of methanol ({sup 12}CH{sub 3}{sup 16}OH, {sup 13}CH{sub 3}{sup 16}OH, {sup 12}CH{sub 3}{sup 18}OH) trapped in neon and nitrogen matrices have been recorded between 11 000 and 200 cm{sup -1}. Their analysis is based on the isotopic effects which slightly modify the frequencies without significantly changing the nature of vibrations nor the band intensities. From the assignment of most of the two quanta transitions 45 out of the 78 anharmonicity coefficients have been deduced. The value of some of them has been confirmed by the identification of three quanta transitions mainly involving the OH stretching mode. The problem of vibrational resonances between methyl bending and stretching modes has been tackled by performing complementary experiments: use of other isotopic species (CH{sub 3}OD, CH{sub 2}DOH) and acquisition of Raman spectra in the gas phase.

  1. A new hybrid observer based rotor imbalance vibration control via passive autobalancer and active bearing actuation

    Science.gov (United States)

    Jung, DaeYi; DeSmidt, Hans

    2018-02-01

    Many researchers have explored the use of active bearings, such as non-contact Active Magnetic Bearings (AMB), to control imbalance vibration in rotor systems. Meanwhile, the advantages of a passive Auto-balancer device (ABD) eliminating the imbalance effect of rotor without using other active means have been recently studied. This paper develops a new hybrid imbalance vibration control approach for an ABD-rotor system supported by a normal passive bearing in augmented with an AMB to enhance the balancing and vibration isolation capabilities. Essentially, an ABD consists of several freely moving eccentric balancing masses mounted on the rotor, which, at supercritical operating speeds, act to cancel the rotor's imbalance at steady-state. However, due to the inherent nonlinearity of the ABD, the potential for other, non-synchronous limit-cycle behavior exists resulting in increased rotor vibration. To address this, the algorithm of proposed hybrid control is designed to guarantee globally asymptotic stability of the synchronous balanced condition. This algorithm also incorporates with a "Luenberger-like" observer that continuously estimates the states of a balancer ball circulating around within ABD. In particular, it is shown that the balanced equilibrium can be made globally attractive under the hybrid control strategy, and that the control power levels of AMB are significantly reduced via the addition of the ABD because the control is designed such that it is only switched on for the abnormal operation of ABD and will be disengaged otherwise. Moreover, unlike other imbalance vibration control applications based upon ABD such as rotor speed regulator [21,22], this approach enables the controller to achieve the desirable performance without altering rotor speed once the rotor initially reaches the target speed. These applications are relevant to limited power applications such as in satellite reaction wheels, flywheel energy storage batteries or CD-ROM application.

  2. Vibration Energy Harvesting Potential for Turbomachinery Applications

    Directory of Open Access Journals (Sweden)

    Adrian STOICESCU

    2018-03-01

    Full Text Available The vibration energy harvesting process represents one of the research directions for increasing power efficiency of electric systems, increasing instrumentation nodes autonomy in hard to reach locations and decreasing total system mass by eliminating cables and higher-power adapters. Research based on the possibility of converting vibration energy into useful electric energy is used to evaluate the potential of its use on turbomachinery applications. Aspects such as the structure and characteristics of piezoelectric generators, harvesting networks, their setup and optimization, are considered. Finally, performance test results are shown using piezoelectric systems on a turbine engine.

  3. The Influence of Various Vibration Frequency on Barium Sulfate Scale Formation Of Vibrated Piping System In The Presence Citric Acid

    Science.gov (United States)

    Karaman, N.; Mangestiyono, W.; Muryanto, S.; Jamari, J.; Bayuseno, A. P.

    2018-01-01

    In this paper, the influence of vibrated piping system for BaSO4 scale formation was investigated. The vibration frequency and presence of citric acid were independent variables determining the kinetics, mass deposit and polymorph of the crystals. Correspondingly, induction time and mass of scale were obtained during the experiments. The crystalline scale was observed by scanning electron microscopy (SEM) and X-Ray Diffraction (XRD) to investigate the morphology and the phase mineral deposits, respectively. This effect indicated that the increase in vibration frequency promoted the increased deposition rate, while the pure barite with a plate-like morphology was produced in the experiments.

  4. Silicon micromachined vibrating gyroscopes

    Science.gov (United States)

    Voss, Ralf

    1997-09-01

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

  5. 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.

  6. 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.

  7. 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

  8. Report on the Stanford/KACST/AMES UVLED small satellite mission to demonstrate charge management of an electrically isolated proof mass for drag-free operation

    Science.gov (United States)

    Saraf, Shailendhar

    A spacecraft demonstration of ultra-violet (UV) LEDs and UV LED charge management based on research done at Stanford University is being developed jointly by the King Abdulaziz City for Science and Technology (KACST) Saudi Arabia and NASA Ames Research Center, with an expected launch date of June 2014. This paper will report on the payload design and testing, mission preparation, satellite launch and payload bring -up in space. Mission lifetime is expected to be at least one month, during which time the ability for the UV LEDs to mitigate actual space-based charging and the effects of radiation on the UV LED device performance will be studied. Precise control over the potential of an electrically isolated proof mass is necessary for the operation of devices such as a Gravitational Reference Sensor (GRS) and satellite missions such as LISA. The mission will demonstrate that AlGaN UV LEDs operating at 255 nm are an effective low-cost, low-power and compact substitute for Mercury vapor lamps used in previous missions. The goal of the mission is to increase the UV LED device to TRL-9 and the charge management system to TRL-7.

  9. Foreword(Advances in Motion and Vibration Control Technology)

    OpenAIRE

    水野, 毅

    2003-01-01

    A new vibration isolation system using negative stiffness realized by active control technique is proposed in this paper. The serial connection of a normal spring and a suspension system with negative stiffness enables the isolation system to have low stiffness for vibration from the ground and high (theoretically infinite) stiffness against direct disturbance acting on the isolation table. A control method of realizing negative stiffness with a linear actuator is presented in an analytical f...

  10. 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

  11. 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...

  12. Improved Laser Vibration Radar

    National Research Council Canada - National Science Library

    Hilaire, Pierre

    1998-01-01

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

  13. NIF Ambient Vibration Measurements

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  14. 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.

  15. Structural Stability and Vibration

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Pedersen, Pauli

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

  16. 2008 Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Philip J. Reid

    2009-09-21

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

  17. Nanoscale piezoelectric vibration energy harvester design

    Science.gov (United States)

    Foruzande, Hamid Reza; Hajnayeb, Ali; Yaghootian, Amin

    2017-09-01

    Development of new nanoscale devices has increased the demand for new types of small-scale energy resources such as ambient vibrations energy harvesters. Among the vibration energy harvesters, piezoelectric energy harvesters (PEHs) can be easily miniaturized and fabricated in micro and nano scales. This change in the dimensions of a PEH leads to a change in its governing equations of motion, and consequently, the predicted harvested energy comparing to a macroscale PEH. In this research, effects of small scale dimensions on the nonlinear vibration and harvested voltage of a nanoscale PEH is studied. The PEH is modeled as a cantilever piezoelectric bimorph nanobeam with a tip mass, using the Euler-Bernoulli beam theory in conjunction with Hamilton's principle. A harmonic base excitation is applied as a model of the ambient vibrations. The nonlocal elasticity theory is used to consider the size effects in the developed model. The derived equations of motion are discretized using the assumed-modes method and solved using the method of multiple scales. Sensitivity analysis for the effect of different parameters of the system in addition to size effects is conducted. The results show the significance of nonlocal elasticity theory in the prediction of system dynamic nonlinear behavior. It is also observed that neglecting the size effects results in lower estimates of the PEH vibration amplitudes. The results pave the way for designing new nanoscale sensors in addition to PEHs.

  18. Development of a Microfluidic Open Interface with Flow Isolated Desorption Volume for the Direct Coupling of SPME Devices to Mass Spectrometry.

    Science.gov (United States)

    Tascon, Marcos; Alam, Md Nazmul; Gómez-Ríos, Germán Augusto; Pawliszyn, Janusz

    2018-02-20

    Technologies that efficiently integrate the sampling and sample preparation steps with direct introduction to mass spectrometry (MS), providing simple and sensitive analytical workflows as well as capabilities for automation, can generate a great impact in a vast variety of fields, such as in clinical, environmental, and food-science applications. In this study, a novel approach that facilitates direct coupling of Bio-SPME devices to MS using a microfluidic design is presented. This technology, named microfluidic open interface (MOI), which operates under the concept of flow-isolated desorption volume, consists of an open-to-ambient desorption chamber (V ≤ 7 μL) connected to an ionization source. Subsequently, compounds of interest are transported to the ionization source by means of the self-aspiration process intrinsic of these interfaces. Thus, any ionization technology that provides a reliable and constant suction, such as electrospray ionization (ESI), atmospheric-pressure chemical ionization (APCI), or inductively coupled plasma ionization (ICP), can be hyphenated to MOI. Using this setup, the desorption chamber is used to release target compounds from the coating, while the isolation of the flow enables the ionization source to be continuously fed with solvent, all without the necessity of employment of additional valves. As a proof of concept, the design was applied to an ESI-MS/MS system for experimental validation. Furthermore, numerical simulations were undertaken to provide a detailed understanding of the fluid flow pattern inside the interface, then used to optimize the system for better efficiency. The analytical workflow of the developed Bio-SPME-MOI-MS setup consists of the direct immersion of SPME fibers into the matrix to extract/enrich analytes of interest within a short period of time, followed by a rinsing step with water to remove potentially adhering proteins, salts, and/or other interfering compounds. Next, the fiber is inserted into the

  19. Evaluation of Bus Vibration Comfort Based on Passenger Crowdsourcing Mode

    Directory of Open Access Journals (Sweden)

    Hong Zhao

    2016-01-01

    Full Text Available Vibration comfort is an important factor affecting the quality of service (QoS of bus. In order to make people involved in supervising bus’s vibration comfort and improve passengers’ riding experience, a novel mode of passenger crowdsourcing is introduced. In this paper, comfort degree of bus vibration is calculated from bus’s vibration signals collected by passengers’ smartphones and sent through WiFi to the Boa web server which shows the vibration comfort on the LCD deployed in bus and maybe trigger alarm lamp when the vibration is beyond the threshold. Three challenges here have been overcome: firstly, space coordinate transformation algorithm is used to solve the constant drift of signals collected; secondly, a low-pass filter is designed to isolate gravity from signals real-timely via limited computing resources; thirdly, an embedded evaluation system is developed according to the calculation procedure specified by criterion ISO 2631-1997. Meanwhile, the model proposed is tested in a practical running environment, the vibration data in whole travel are recorded and analyzed offline. The results show that comfort degree of vibration obtained from the experimental system is identical with the truth, and this mode is proved to be effective.

  20. CaSO4 Scale Formation on Vibrated Piping System in the Presence Citric Acid

    Science.gov (United States)

    Mangestiyono, W.; Jamari, J.; Muryanto, S.; Bayuseno, A. P.

    2018-02-01

    Vibration in many industries commonly generated by the operation mechanical equipment such as extruder, mixer, blower, compressor, turbine, generator etc. Vibration propagates into the floor and attacks the pipe around those mechanical equipment. In this paper, the influence of vibration in a pipe on the CaSO4 scale formation was investigated to understand the effect of vibration on the kinetics, mass of scale, crystal phases and crystal polymorph. To generate vibration force, mechanical equipment was prepared consisted of electrical motor, crankshaft, connecting rod and a vibration table at where test pipe section mounted. Deposition rate increased significantly when the vibration affected to the system i.e. 0.5997 and 1.6705 gr/hr for vibration frequency 4.00 and 8.00 Hz. The addition 10.00 ppm of citric acid declined the deposition rate of 8 Hz experiment from 3.4599 gr/hr to 2.2865 gr/hr.

  1. Vibration analysis of the piping system using the modal analysis method, 1

    International Nuclear Information System (INIS)

    Fujikawa, Takeshi; Kurohashi, Michiya; Inoue, Yoshio

    1975-01-01

    Modal analysis method was developed for the vibration analysis of piping system in nuclear or chemical plants, with finite element theory, and verified by sinusoidal vibration method. The natural vibration equation for pipings was derived with stiffness, attenuation and mass matrices, and eigenvalues are obtained with usual method, then the forced vibration equation for pipings was derived with the same manner, and the special solutions are given by modal method from the eigenvalues of the natural vibration equation. Three simple piping models (one, two and three dimensional) were made, and the natural vibration frequency was measured with forced input from an electrical dynamic shaker and a sound speaker. The experimental values of natural vibration frequency showed good agreement with the results by the analytical method. Therefore the theoretical approach for piping system vibration was proved to be valid. (Iwase, T.)

  2. Optimal cost design of base-isolated pool structures for the storage of nuclear spent fuel

    International Nuclear Information System (INIS)

    Ko, H. M.; Park, K. S.; Song, J. H.

    1999-01-01

    A method of cost-effectiveness evaluation for seismic isolated pool structures is presented. Input ground motion is modeled as spectral density function compatible with response spectrum for combination of acceleration coefficient and site coefficient. Interaction effects between flexible walls and contained fluid are considered in the form of added mass matrix. Wall thickness and isolator stiffness are adopted as design variables for optimization. Transfer function vector of the structure-isolator system is derived from the equation of motion. Spectral analysis method based on random vibration theories is used for the calculation of failure probability. The exemplifying designs and analyses show that cost-effectiveness of isolated pool structure is relatively high in low-moderate seismic region and stiff soil condition. Sensitiveness of optimal design variables to assumed damage scales is relatively low in such region

  3. Flow induced vibrations of piping

    International Nuclear Information System (INIS)

    Gibert, R.J.; Axisa, F.

    1977-01-01

    In order to design the supports of piping systems, estimations of the vibrations induced by the fluid conveyed through the pipes are generally needed. For that purpose it is necessary to calculate the model parameters of liquid containing pipes. In most computer codes, fluid effects are accounted for just by adding the fuid mass to the structure. This may lead to serious errors.- Inertial effects from the fluid are not correctly evaluated especially in the case of bended or of non-uniform section pipes. Fluid boundary conditions are simply ignored. - In many practical problems fluid compressibility cannot be negelcted, even in the low frequencies domain which corresponds to efficient excitation by turbulent sources of the flow. This paper presents a method to take into account these efects, by solving a coupled mechanical acoustical problem: the computer code TEDEL of the C.E.A./D.E.M.T. System, based on the finite-elements method, has been extended to calculate simultaneously the pressure fluctuations in the fluid and the vibrations of the pipe. (Auth.)

  4. Identification and reduction of piping-vibrations in plants

    Energy Technology Data Exchange (ETDEWEB)

    Kerkhof, K. [Stuttgart Univ. (Germany). MPA

    2012-07-01

    Safe operation, availability and lifetime assessment of piping systems are of utmost concern for plant operators. The use of tuned mass dampers is a rather new approach for reducing vibrations to avoid high cycle fatigue in a large chemical piping system. The investigated piping system is supported by a tall structure fixed at the base. As a result, the steel building stiffness decreases with height. Furthermore large piping-elbow forces act at the top of the building, which lead to large vibration amplitudes. Since both piping system and supporting structure exhibited these large vibration amplitudes, dampers or shock absorbers placed between them would prove ineffective. Therefore, special vibration absorbers were developed for such piping systems. The paper presents the design process, starting with an extensive system investigation up to the passive multi-axial vibration absorber design parameters. This includes: Laboratory tests with a mock-up pipe system, where the first design ideas for new passive vibration absorbers were investigated. Vibration measurements were carried out to investigate the current state of the vibration behaviour. The piping system was inspected; strain gauges were used to identify stress concentrations at welds and other notches due to ovalization. Finite element calculations were performed, first as a combined beam and shell model for the pipe without the support structure. A detailed model for the combined steel construction and pipe system was created. Model-updating was done to fit the calculated model to the experimental modal analysis data. Loading assumptions describing excitation forces from the mass flow were checked. Harmonic frequency analysis was performed. On the basis of these calculations design parameters for the passive vibration absorber were determined. Finally, a solution for the design of two passive vibration absorbers will be presented.

  5. Identification and reduction of piping-vibrations in plants

    International Nuclear Information System (INIS)

    Kerkhof, K.

    2012-01-01

    Safe operation, availability and lifetime assessment of piping systems are of utmost concern for plant operators. The use of tuned mass dampers is a rather new approach for reducing vibrations to avoid high cycle fatigue in a large chemical piping system. The investigated piping system is supported by a tall structure fixed at the base. As a result, the steel building stiffness decreases with height. Furthermore large piping-elbow forces act at the top of the building, which lead to large vibration amplitudes. Since both piping system and supporting structure exhibited these large vibration amplitudes, dampers or shock absorbers placed between them would prove ineffective. Therefore, special vibration absorbers were developed for such piping systems. The paper presents the design process, starting with an extensive system investigation up to the passive multi-axial vibration absorber design parameters. This includes: Laboratory tests with a mock-up pipe system, where the first design ideas for new passive vibration absorbers were investigated. Vibration measurements were carried out to investigate the current state of the vibration behaviour. The piping system was inspected; strain gauges were used to identify stress concentrations at welds and other notches due to ovalization. Finite element calculations were performed, first as a combined beam and shell model for the pipe without the support structure. A detailed model for the combined steel construction and pipe system was created. Model-updating was done to fit the calculated model to the experimental modal analysis data. Loading assumptions describing excitation forces from the mass flow were checked. Harmonic frequency analysis was performed. On the basis of these calculations design parameters for the passive vibration absorber were determined. Finally, a solution for the design of two passive vibration absorbers will be presented.

  6. MR Damper Controlled Vibration Absorber for Enhanced Mitigation of Harmonic Vibrations

    Directory of Open Access Journals (Sweden)

    Felix Weber

    2016-12-01

    Full Text Available This paper describes a semi-active vibration absorber (SVA concept based on a real-time controlled magnetorheological damper (MR-SVA for the enhanced mitigation of structural vibrations due to harmonic disturbing forces. The force of the MR damper is controlled in real-time to generate the frequency and damping controls according to the behaviour of the undamped vibration absorber for the actual frequency of vibration. As stiffness and damping emulations in semi-active actuators are coupled quantities the control is formulated to prioritize the frequency control by the controlled stiffness. The control algorithm is augmented by a stiffness correction method ensuring precise frequency control when the desired control force is constrained by the semi-active restriction and residual force of the MR damper. The force tracking task is solved by a model-based feed forward with feedback correction. The MR-SVA is numerically and experimentally validated for the primary structure with nominal eigenfrequency and when de-tuning of −10%, −5%, +5% and +10% is present. Both validations demonstrate that the MR-SVA improves the vibration reduction in the primary structure by up to 55% compared to the passive tuned mass damper (TMD. Furthermore, it is shown that the MR-SVA with only 80% of tuned mass leads to approximately the same enhanced performance while the associated increased relative motion amplitude of the tuned mass is more than compensated be the reduced dimensions of the mass. Therefore, the MR-SVA is an appropriate solution for the mitigation of tall buildings where the pendulum mass can be up to several thousands of metric tonnes and space for the pendulum damper is limited.

  7. Design of a nonlinear torsional vibration absorber

    Science.gov (United States)

    Tahir, Ammaar Bin

    Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

  8. 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.

  9. Hydrodynamics induced vibration to trash-racks

    International Nuclear Information System (INIS)

    Sadrnejad, A.

    2002-01-01

    In conventional power plants trash-racks are provided at the intakes to protect the turbines. In pumped storage plants, the draft tube or tailrace must also have trash-racks to protect the units while pumping. Because the loads believed to cause many failures of trash-racks are dynamic in nature, it is important to understand the dynamic characteristics of trash-racks structures in general and a single rack in particular. The classical added-mass solution structure-fluid dynamic interaction is known as an approximate solution procedure. An accurate added-mass approach mixed with implementation in finite element framework is proposed. In this proposal, experimental conclusions, supported by theory, led to presentation of more accurate results in vibration of trash-racks. This numerical solution as a powerful method to solve such a complex problem can be employed to carry out dynamic characteristics of these structures while vibrating in water

  10. Report of workshop on vibration related to fluid in atomic energy field. 4

    International Nuclear Information System (INIS)

    1993-01-01

    This is the fourth workshop on the vibration related to fluid in atomic energy field of Yayoi research group. This time, two topics were taken up. One is edgetone phenomena and the liquid surface vibration phenomena due to flow. Another is the introduction of the experience in light water reactors. The workshop was held on August 30 and 31, 1993 at Nuclear Engineering Research Laboratory, University of Tokyo. At the workshop, lectures were given on the mechanism of occurrence of edgetone, the theoretical analysis of edgetone and edgenoise, the self-excited vibration of free liquid surface due to vertical plane jet and vertical cylindrical jet, the research on flow instability phenomena in parallel loop system, the irregular vibration behavior of U-shaped tubes excited by flow, the research on the vibration of cyclindrical weir due to fluid discharge, the examples of the vibration related to fluid in LWRs, the estimation of fatigue phenomena in bearing rings, the vibration of rotary vanes and verifying test, the analysis of flow in isolated phase bus plate vane and the measurement of velocity distribution, flow in piping and the behavior of valve vibration, the condition for the occurrence of flow vibration in the main steam separation valve of BWR, the vibration of piping due to orifice, the analysis of flow in two-dimensional vibrating cascade, and the subjects of fluid vibration assessment in atomic energy. (K.I.)

  11. 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.

  12. Two-phase flow induced parametric vibrations in structural systems

    International Nuclear Information System (INIS)

    Hara, Fumio

    1980-01-01

    This paper is divided into two parts concerning piping systems and a nuclear fuel pin system. The significant experimental results concerning the random vibration induced in an L-shaped pipe by air-water two-phase flow and the theoretical analysis of the vibration are described in the first part. It was clarified for the first time that the parametric excitation due to the periodic changes of system mass, centrifugal force and Coriolis force was the mechanism of exciting the vibration. Moreover, the experimental and theoretical analyses of the mechanism of exciting vibration by air-water two-phase flow in a straight, horizontal pipe were carried out, and the first natural frequency of the piping system was strongly related to the dominant frequency of void signals. The experimental results on the vibration of a nuclear fuel pin model in parallel air-water two-phase flow are reported in the latter part. The relations between vibrational strain variance and two-phase flow velocity or pressure fluctuation, and the frequency characteristics of vibrational strain variance were obtained. The theoretical analysis of the dynamic interaction between air-water two-phase flow and a fuel pin structure, and the vibrational instability of fuel pins in alternate air and water slugs or in large bubble flow are also reported. (Kako, I.)

  13. Vibrations in orthopedics.

    Science.gov (United States)

    Nokes, L D; Thorne, G C

    1988-01-01

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

  14. Vibrations of a delivery car excited by railway track crossing

    International Nuclear Information System (INIS)

    Litak, Grzegorz; Borowiec, Marek; Hunicz, Jacek; Koszalka, Grzegorz; Niewczas, Andrzej

    2009-01-01

    Vertical vibrations of a delivery car passing through railway tracks have been investigated in this paper. The application of recurrence plots allows to examine short time series of acceleration non-stationary courses. Recurrence quantification analysis and square deviations estimated in small windows have been used to monitor car vibrations and transient behaviour. Measuring acceleration on the 'sprung' and 'unsprung' masses of a vehicle has enabled also to test the quality of a car suspension.

  15. Vibration-free stirling cryocooler for high definition microscopy

    Science.gov (United States)

    Riabzev, S. V.; Veprik, A. M.; Vilenchik, H. S.; Pundak, N.; Castiel, E.

    2009-12-01

    -axes suppression of the residual wideband vibration, thermo-conductive vibration isolation struts and soft vibration mounts. The attainable performance of the resulting vibration free linear Stirling cryocooler (Ricor model K535-ULV) is evaluated through a full-scale experimentation.

  16. Vibrational spectra of aminoacetonitrile

    International Nuclear Information System (INIS)

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

    1975-01-01

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

  17. Vibrations and waves

    CERN Document Server

    Kaliski, S

    2013-01-01

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

  18. Vibration Theory, Vol. 3

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

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

  19. A vibration correction method for free-fall absolute gravimeters

    Science.gov (United States)

    Qian, J.; Wang, G.; Wu, K.; Wang, L. J.

    2018-02-01

    An accurate determination of gravitational acceleration, usually approximated as 9.8 m s-2, has been playing an important role in the areas of metrology, geophysics, and geodetics. Absolute gravimetry has been experiencing rapid developments in recent years. Most absolute gravimeters today employ a free-fall method to measure gravitational acceleration. Noise from ground vibration has become one of the most serious factors limiting measurement precision. Compared to vibration isolators, the vibration correction method is a simple and feasible way to reduce the influence of ground vibrations. A modified vibration correction method is proposed and demonstrated. A two-dimensional golden section search algorithm is used to search for the best parameters of the hypothetical transfer function. Experiments using a T-1 absolute gravimeter are performed. It is verified that for an identical group of drop data, the modified method proposed in this paper can achieve better correction effects with much less computation than previous methods. Compared to vibration isolators, the correction method applies to more hostile environments and even dynamic platforms, and is expected to be used in a wider range of applications.

  20. Research on Effects of Blast Casting Vibration and Vibration Absorption of Presplitting Blasting in Open Cast Mine

    Directory of Open Access Journals (Sweden)

    Li Ma

    2016-01-01

    Full Text Available The impact energy produced by blast casting is able to break and cast rocks, yet the strong vibration effects caused at the same time would threaten the safety of mines. Based on the theory of Janbu’s Limit Equilibrium Method (LEM, pseudo-static method has been incorporated to analyze the influence of dynamic loads of blasting on slope stability. The horizontal loads produced by blast vibrations cause an increase in sliding forces, and this leads to a lower slope stability coefficient. When the tensile stresses of the two adjacent blast holes are greater than the tensile strength of rock mass, the radical oriented cracks are formed, which is the precondition for the formation of presplit face. Thus, the formula for calculating the blast hole spacing of presplit blasting can be obtained. Based on the analysis of the principles of vibration tester and vibration pick-up in detecting blast vibrations, a detection scheme of blast vibration is worked out by taking the blast area with precrack rear and non-precrack side of the detection object. The detection and research results of blast vibration show that presplit blasting can reduce the attenuation coefficient of stress wave by half, and the vibration absorption ratio could reach 50.2%; the impact of dynamic loads on the end-wall slope stability coefficient is 1.98%, which proves that presplit blasting plays an important role in shock absorption of blast casting.

  1. Bubble Size Distribution in a Vibrating Bubble Column

    Science.gov (United States)

    Mohagheghian, Shahrouz; Wilson, Trevor; Valenzuela, Bret; Hinds, Tyler; Moseni, Kevin; Elbing, Brian

    2016-11-01

    While vibrating bubble columns have increased the mass transfer between phases, a universal scaling law remains elusive. Attempts to predict mass transfer rates in large industrial scale applications by extrapolating laboratory scale models have failed. In a stationary bubble column, mass transfer is a function of phase interfacial area (PIA), while PIA is determined based on the bubble size distribution (BSD). On the other hand, BSD is influenced by the injection characteristics and liquid phase dynamics and properties. Vibration modifies the BSD by impacting the gas and gas-liquid dynamics. This work uses a vibrating cylindrical bubble column to investigate the effect of gas injection and vibration characteristics on the BSD. The bubble column has a 10 cm diameter and was filled with water to a depth of 90 cm above the tip of the orifice tube injector. BSD was measured using high-speed imaging to determine the projected area of individual bubbles, which the nominal bubble diameter was then calculated assuming spherical bubbles. The BSD dependence on the distance from the injector, injector design (1.6 and 0.8 mm ID), air flow rates (0.5 to 5 lit/min), and vibration conditions (stationary and vibration conditions varying amplitude and frequency) will be presented. In addition to mean data, higher order statistics will also be provided.

  2. Heterogeneous Dynamics of Coupled Vibrations

    NARCIS (Netherlands)

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

    2009-01-01

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

  3. 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.

  4. Reducing vibration transfer from power plants by active methods

    Science.gov (United States)

    Kiryukhin, A. V.; Milman, O. O.; Ptakhin, A. V.

    2017-12-01

    The possibility of applying the methods of active damping of vibration and pressure pulsations for reducing their transfer from power plants into the environment, the seating, and the industrial premises are considered. The results of experimental works implemented by the authors on the active broadband damping of vibration and dynamic forces after shock-absorption up to 15 dB in the frequency band up to 150 Hz, of water pressure pulsations in the pipeline up to 20 dB in the frequency band up to 600 Hz, and of spatial low-frequency air noise indoors of a diesel generator at discrete frequency up to 20 dB are presented. It is shown that a reduction of vibration transfer through a vibration-isolating junction (expansion joints) of pipelines with liquid is the most complicated and has hardly been developed so far. This problem is essential for vibration isolation of power equipment from the seating and the environment through pipelines with water and steam in the power and transport engineering, shipbuilding, and in oil and gas pipelines in pumping stations. For improving efficiency, reducing the energy consumption, and decreasing the overall dimensions of equipment, it is advisable to combine the work of an active system with passive damping means, the use of which is not always sufficient. The executive component of the systems of active damping should be placed behind the vibration isolators (expansion joints). It is shown that the existence of working medium and connection of vibration with pressure pulsations in existing designs of pipeline expansion joints lead to growth of vibration stiffness of the expansion joint with the environment by two and more orders as compared with the static stiffness and makes difficulties for using the active methods. For active damping of vibration transfer through expansion joints of pipelines with a liquid, it is necessary to develop expansion joint structures with minimal connection of vibrations and pulsations and minimal

  5. Delineation of Stenotrophomonas maltophilia isolates from cystic fibrosis patients by fatty acid methyl ester profiles and matrix-assisted laser desorption/ionization time-of-flight mass spectra using hierarchical cluster analysis and principal component analysis.

    Science.gov (United States)

    Vidigal, Pedrina Gonçalves; Mosel, Frank; Koehling, Hedda Luise; Mueller, Karl Dieter; Buer, Jan; Rath, Peter Michael; Steinmann, Joerg

    2014-12-01

    Stenotrophomonas maltophilia is an opportunist multidrug-resistant pathogen that causes a wide range of nosocomial infections. Various cystic fibrosis (CF) centres have reported an increasing prevalence of S. maltophilia colonization/infection among patients with this disease. The purpose of this study was to assess specific fingerprints of S. maltophilia isolates from CF patients (n = 71) by investigating fatty acid methyl esters (FAMEs) through gas chromatography (GC) and highly abundant proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and to compare them with isolates obtained from intensive care unit (ICU) patients (n = 20) and the environment (n = 11). Principal component analysis (PCA) of GC-FAME patterns did not reveal a clustering corresponding to distinct CF, ICU or environmental types. Based on the peak area index, it was observed that S. maltophilia isolates from CF patients produced significantly higher amounts of fatty acids in comparison with ICU patients and the environmental isolates. Hierarchical cluster analysis (HCA) based on the MALDI-TOF MS peak profiles of S. maltophilia revealed the presence of five large clusters, suggesting a high phenotypic diversity. Although HCA of MALDI-TOF mass spectra did not result in distinct clusters predominantly composed of CF isolates, PCA revealed the presence of a distinct cluster composed of S. maltophilia isolates from CF patients. Our data suggest that S. maltophilia colonizing CF patients tend to modify not only their fatty acid patterns but also their protein patterns as a response to adaptation in the unfavourable environment of the CF lung. © 2014 The Authors.

  6. Approaches for reducing structural vibration of the carbody railway vehicles

    Directory of Open Access Journals (Sweden)

    Dumitriu Mădălina

    2017-01-01

    Full Text Available Reducing the weight of the railway vehicles stands as a decisive rule in their design, entailed by higher velocities, the need to consume less energy and lower the manufacturing costs, along with the maximization of the use of loads on the axle. Once complied with this rule, the vehicle flexibility increases and leads to an easy excitation of the structural vibrations in the carbody, with an impact upon the ride comfort in the railway vehicle. For a better ride comfort in lightweight railway vehicles, both vibration isolation approaches and structural damping approaches have been introduced. The paper herein submits a brief review of the main structural damping approaches aiming to reduce the amplitude in the carbody structural vibrations, based on the use of the piezoelectric elements in passive control schemes. The paper outcomes show the potential of the presented methods concerning the reduction of the flexible vibrations in the carbody and the ride comfort improvement.

  7. Structural Stability and Vibration

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Pedersen, Pauli

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

  8. Vibrational Spectroscopy and Astrobiology

    Science.gov (United States)

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

    2001-01-01

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

  9. Vibrations and Eigenvalues

    Indian Academy of Sciences (India)

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

  10. Heat exchanger vibration

    International Nuclear Information System (INIS)

    Richards, D.J.W.

    1977-01-01

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

  11. Man-Induced Vibrations

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Hansen, Lars Pilegaard

    1994-01-01

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

  12. Heat exchanger vibration

    Energy Technology Data Exchange (ETDEWEB)

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

    1977-12-01

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

  13. Study on design method and vibration reduction characteristic of floating raft with periodic structure

    Science.gov (United States)

    Fang, Yuanyuan; Zuo, Yanyan; Xia, Zhaowang

    2018-03-01

    The noise level is getting higher with the development of high-power marine power plant. Mechanical noise is one of the most obvious noise sources which not only affect equipment reliability, riding comfort and working environment, but also enlarge underwater noise. The periodic truss type device which is commonly applied in fields of aerospace and architectural is introduced to floating raft construction in ship. Four different raft frame structure are designed in the paper. The vibration transmissibility is taken as an evaluation index to measure vibration isolation effect. A design scheme with the best vibration isolation effect is found by numerical method. Plate type and the optimized periodic truss type raft frame structure are processed to experimental verify vibration isolation effect of the structure of the periodic raft. The experimental results demonstrate that the same quality of the periodic truss floating raft has better isolation effect than that of the plate type floating raft.

  14. 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

  15. 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.

  16. Mass Society

    DEFF Research Database (Denmark)

    Borch, Christian

    2017-01-01

    the negative features usually ascribed by late nineteenth-century crowd psychology to spontaneous crowds, and attributes these to the entire social fabric. However, in contrast to crowd psychology, theorists of mass society often place greater emphasis on how capitalism, technological advances, or demographic......Mass society is a societal diagnosis that emphasizes – usually in a pejorative, modernity critical manner – a series of traits allegedly associated with modern society, such as the leveling of individuality, moral decay, alienation, and isolation. As such, the notion of mass society generalizes...... developments condition such negative features, and some theorists argue that mass society produces a propensity to totalitarianism. Discussions of mass society culminated in the early and mid-twentieth century....

  17. Fluid elastic vibration of nuclear fuel assemblies

    International Nuclear Information System (INIS)

    Kim, S. N.; Jung, S. Y.

    1998-01-01

    Since utilities and fuel venders have adopted the fuel design of high burn-up and improved thermal margin flow mixing vane, several PWR nuclear power plants have in recent years experienced fretting wear fuel rod failure due to flow induced vibration. Flow induced vibration can be resulted from fluidelastic instability, periodic shedding, turbulence-induced excitation, and acoustic resonance (1). Among these mechanisms found in the core of nuclear power plant, the governing mechanism that is fluidelastic instability, could be inferred from the analysis of fuel failure patterns. Therefore, to simulate the fuel failure in nuclear power plants, Tanaka's model (2) was chosen as most suitable one, which is well explaining the damage pattern, in particular it's second row damage characteristics. In the model, unsteady fluid dynamic forces acting on the vibrating cyclinders were included which consists of the inertia forces due to the added mass of fluid, damping forces of fluid in phase to the cylinder vibrating velocity, and stiffness forces proportional to cylinder displacements. However, the model did not account for radiation effect-spring forces deflection. So, the model was modified to account for the spring force relaxation due to radiation exposure. The stiffness of spring was fitted with experimental data. Finally the critical velocities were calculated with the modified spring force at beginning and end of cycle

  18. 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.

  19. 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

  20. Design of a Maglev Vibration Test Platform for the Research of Maglev Vehicle-girder Coupled Vibration Problem

    Directory of Open Access Journals (Sweden)

    Zhou Danfeng

    2017-01-01

    Full Text Available The maglev vehicle-girder coupled vibration problem has been encountered in many maglev test or commercial lines, which significantly degrade the performance of the maglev train. In previous research on the principle of the coupled vibration problem, it has been discovered that the fundamental model of the maglev girder can be simplified as a series of mass-spring resonators of different but related resonance frequencies, and that the stability of the vehicle-girder coupled system can be investigated by separately examining the stability of each mass-spring resonator – electromagnet coupled system. Based on this conclusion, a maglev test platform, which includes a single electromagnetic suspension control system, is built for experimental study of the coupled vibration problem. The guideway of the test platform is supported by a number of springs so as to change its flexibility. The mass of the guideway can also be changed by adjusting extra weights attached to it. By changing the flexibility and mass of the guideway, the rules of the maglev vehicle-girder coupled vibration problem are to be examined through experiments, and related theory on the vehicle-girder self-excited vibration proposed in previous research is also testified.

  1. Vibration characteristics analysis for HANARO fuel assembly

    International Nuclear Information System (INIS)

    Ryu, Jeong Soo; Yoon, Doo Byung

    2001-06-01

    For investigating the vibration characteristics of HANARO fuel assembly, the finite element models of the in-air fuel assemblies and flow tubes were developed. By calculating the hydrodynamic mass and distributing it on the in-air models, the in-water models of the flow tubes and the fuel assemblies were developed. Then, modal analysis of the developed models was carried out. The analysis results show that the fundamental vibration modes of the in-air 18-element and 36-element fuel assemblies are lateral bending modes and its corresponding natural frequencies are 26.4Hz and 27.7Hz, respectively. The fundamental natural frequency of the in-water 18-element and 36-element fuel assemblies were obtained as 16.1Hz and 16.5Hz. For the verification of the developed finite element models, modal analysis results were compared with those obtained from the modal test. These results demonstrate that the natural frequencies of lower order modes obtained from finite element analysis agree well with those of the modal test and the estimation of the hydrodynamic mass is appropriate. It is expected that the analysis results will be applied as a basic data for the operation and management of the HANARO. In addition, when it is necessary to improve the design of the fuel assembly, the developed finite element models will be utilized as a base model for the vibration characteristic analysis of the modified fuel assembly

  2. Energy scavenging from environmental vibration.

    Energy Technology Data Exchange (ETDEWEB)

    Galchev, Tzeno (University of Michigan); Apblett, Christopher Alan; Najafi, Khalil (University of Michigan)

    2009-10-01

    The goal of this project is to develop an efficient energy scavenger for converting ambient low-frequency vibrations into electrical power. In order to achieve this a novel inertial micro power generator architecture has been developed that utilizes the bi-stable motion of a mechanical mass to convert a broad range of low-frequency (< 30Hz), and large-deflection (>250 {micro}m) ambient vibrations into high-frequency electrical output energy. The generator incorporates a bi-stable mechanical structure to initiate high-frequency mechanical oscillations in an electromagnetic scavenger. This frequency up-conversion technique enhances the electromechanical coupling and increases the generated power. This architecture is called the Parametric Frequency Increased Generator (PFIG). Three generations of the device have been fabricated. It was first demonstrated using a larger bench-top prototype that had a functional volume of 3.7cm3. It generated a peak power of 558{micro}W and an average power of 39.5{micro}W at an input acceleration of 1g applied at 10 Hz. The performance of this device has still not been matched by any other reported work. It yielded the best power density and efficiency for any scavenger operating from low-frequency (<10Hz) vibrations. A second-generation device was then fabricated. It generated a peak power of 288{micro}W and an average power of 5.8{micro}W from an input acceleration of 9.8m/s{sup 2} at 10Hz. The device operates over a frequency range of 20Hz. The internal volume of the generator is 2.1cm{sup 3} (3.7cm{sup 3} including casing), half of a standard AA battery. Lastly, a piezoelectric version of the PFIG is currently being developed. This device clearly demonstrates one of the key features of the PFIG architecture, namely that it is suitable for MEMS integration, more so than resonant generators, by incorporating a brittle bulk piezoelectric ceramic. This is the first micro-scale piezoelectric generator capable of <10Hz operation. The

  3. DEMT experimental and analytical studies on seismic isolation

    International Nuclear Information System (INIS)

    Gantenbein, F.; Buland, P.

    1989-01-01

    Work on seismic isolation has been performed in France for many years, and the isolation device developed by SPIE-BATIGNOLLES in collaboration with Electricite de France (EDF) has been incorporated in the design of pressurized-water reactor (PWR) nuclear power plants. This paper reviews the experimental and theoretical studies performed at CEA/DEMT related to the overall behavior of isolated structures. The experimental work consists of the seismic shaking-table tests of a concrete cylinder isolated by neoprene sliding pads, and the vibrational tests on the reaction mass of the TAMARIS seismic facility. The analytical work consists of the development of procedures for dynamic calculation methods: for soil-structure interaction where pads are placed between an upper raft and pedestals, for time-history calculations where sliding plates are used, and for fluid-structure interaction where coupled fluid and structure motions and sloshing modes are important. Finally, this paper comments on the consequences of seismic isolation for the analysis of fast breeder reactor (FBR) vessels. The modes can no longer be considered independent (SRSS Method leads to important errors), and the sloshing increases

  4. Analysis of algorithms for detection of resonance frequencies in vibration measurements on super heater tubes; Analys av algoritmer foer detektering av resonansfrekvenser i vibrationsmaetningar paa oeverhettartuber

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Daniel

    2010-07-01

    Combustion of fuel in thermal power plants emits particles which creates coatings on the super heater tubes. The coatings isolate the tubes and impairs the efficiency of the heat transfer. Cleaning the tubes occurs while the power plant is running but without any knowledge of the actual coating. A change in frequency corresponds to a change in mass of the coatings. This thesis has been focusing in estimating resonance frequencies in vibration measurements made by strain gauges on the tubes. To improve the estimations a target tracking algorithm had been added. The results indicates that it is possible to estimate the resonance frequencies but the algorithms need to be verified on more signals.

  5. Vibrations of alkali metal overlayers on metal surfaces

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  6. Phenotypic H-Antigen Typing by Mass Spectrometry Combined with Genetic Typing of H Antigens, O Antigens, and Toxins by Whole-Genome Sequencing Enhances Identification of Escherichia coli Isolates.

    Science.gov (United States)

    Cheng, Keding; Chui, Huixia; Domish, Larissa; Sloan, Angela; Hernandez, Drexler; McCorrister, Stuart; Robinson, Alyssia; Walker, Matthew; Peterson, Lorea A M; Majcher, Miles; Ratnam, Sam; Haldane, David J M; Bekal, Sadjia; Wylie, John; Chui, Linda; Tyler, Shaun; Xu, Bianli; Reimer, Aleisha; Nadon, Celine; Knox, J David; Wang, Gehua

    2016-08-01

    Mass spectrometry-based phenotypic H-antigen typing (MS-H) combined with whole-genome-sequencing-based genetic identification of H antigens, O antigens, and toxins (WGS-HOT) was used to type 60 clinical Escherichia coli isolates, 43 of which were previously identified as nonmotile, H type undetermined, or O rough by serotyping or having shown discordant MS-H and serotyping results. Whole-genome sequencing confirmed that MS-H was able to provide more accurate data regarding H antigen expression than serotyping. Further, enhanced and more confident O antigen identification resulted from gene cluster based typing in combination with conventional typing based on the gene pair comprising wzx and wzy and that comprising wzm and wzt The O antigen was identified in 94.6% of the isolates when the two genetic O typing approaches (gene pair and gene cluster) were used in conjunction, in comparison to 78.6% when the gene pair database was used alone. In addition, 98.2% of the isolates showed the existence of genes for various toxins and/or virulence factors, among which verotoxins (Shiga toxin 1 and/or Shiga toxin 2) were 100% concordant with conventional PCR based testing results. With more applications of mass spectrometry and whole-genome sequencing in clinical microbiology laboratories, this combined phenotypic and genetic typing platform (MS-H plus WGS-HOT) should be ideal for pathogenic E. coli typing. Copyright © 2016 Cheng et al.

  7. Resonant vibration control of wind turbine blades

    DEFF Research Database (Denmark)

    Svendsen, Martin Nymann; Krenk, Steen; Høgsberg, Jan Becker

    2010-01-01

    . The efficiency of the resonant controller is demonstrated for a representative turbine blade exposed to turbulent wind loading. It is found that the present explicit tuning procedure yields close to optimal tuning, with very limited modal spill-over and effective reduction of the vibration amplitudes.......The paper deals with introduction of damping to specific vibration modes of wind turbine blades, using a resonant controller with acceleration feedback. The wind turbine blade is represented by three-dimensional, two-node finite elements in a local, rotating frame of reference. The element...... formulation accounts for arbitrary mass density distributions, general elastic crosssection properties and geometric stiffness effects due to internal stresses. A compact, linear formulation for aerodynamic forces with associated stiffness and damping terms is established and added to the structural model...

  8. Vibration Reduction System Using Magnetic Suspension Technology

    Directory of Open Access Journals (Sweden)

    Spychała Jarosław

    2015-01-01

    Full Text Available The article presents considerations concerning the construction of vibration reduction system using magnetic suspension technology. Presents the results of simulation, numerical and experimental the bearingless electric motor, for which successfully used this type of solution. Positive results of research and testing have become the basis for the development of the concept of building this type of active vibration reduction system , at the same time acting as a support for a technical object, which is a jet engine. Bearing failures are manifested by loss or distortion of their mass, which leads to a total destruction of the roller bearing, and thus reflected in the security. The article presents the concept of building active magnetic suspension to eliminate the bearing system of classical rolling bearing and replace it with magnetic bearing.

  9. Pickin’ up good vibrations

    CERN Multimedia

    Katarina Anthony

    2015-01-01

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

  10. Vibrational stability of graphene

    Directory of Open Access Journals (Sweden)

    Yangfan Hu

    2013-05-01

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

  11. D.E.M.T. Experimental and analytical studies on seismic isolation

    International Nuclear Information System (INIS)

    Gantenbein, F.; Buland, P.

    1989-01-01

    The various studies which have been performed in C.E.A./D.E.M.T. will be reviewed in the paper. They are experimental or theoretical and related to the overall behavior of isolated structures. Among the experimental work one can notice: - the seismic tests on a shaking table of a concrete cylinder isolated by sliding neoprene pads, - the vibrational tests on the reaction mass of TAMARIS seismic facility. The analytical work consists of dynamic calculation method development: - for the soil structure interaction in case of pads interposed between an upper raft and pedestals; - for the time history calculation of sliding structures; - for fluid structure interaction (coupling of fluid and structure motion or sloshing modes). Finally comments will be given on the seismic isolation consequencies for the analysis of F.B.R. vessels: the modes can no more be considered independent (SRSS method leads to important errors), the sloshing increases

  12. 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...

  13. On the control of vibrations using synchrophasing

    Science.gov (United States)

    Dench, M. R.; Brennan, M. J.; Ferguson, N. S.

    2013-09-01

    This paper describes the application of a technique, known as synchrophasing, to the control of machinery vibration. It is applicable to machinery installations, in which several synchronous machines, such as those driven by electrical motors, are fitted to an isolated common structure known as a machinery raft. To reduce the vibration transmitted to the host structure to which the machinery raft is attached, the phase of the electrical supply to the motors is adjusted so that the net transmitted force to the host structure is minimised. It is shown that while this is relatively simple for an installation consisting of two machines, it is more complicated for installations in which there are more than two machines, because of the interaction between the forces generated by each machine. The development of a synchrophasing scheme, which has been applied to propeller aircraft, and is known as Propeller Signature Theory (PST) is discussed. It is shown both theoretically and experimentally, that this is an efficient way of controlling the phase of multiple machines. It is also shown that synchrophasing is a worthwhile vibration control technique, which has the potential to suppress vibration transmitted to the host structure by up to 20 dB at certain frequencies. Although the principle of synchronisation has been demonstrated on a one-dimensional structure, it is believed that this captures the key features of the approach. However, it should be realised that the mode-shapes of a machinery raft may be more complex than that of a one-dimensional structure and this may need to be taken into account in a real application.

  14. Vibration damping method and apparatus

    Science.gov (United States)

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

    1999-01-01

    The present invention provides vibration damping method and apparatus that can damp vibration in more than one direction without requiring disassembly, that can accommodate varying tool dimensions without requiring re-tuning, and that does not interfere with tool tip operations and cooling. The present invention provides active dampening by generating bending moments internal to a structure such as a boring bar to dampen vibration thereof.

  15. Atomic beams probe surface vibrations

    International Nuclear Information System (INIS)

    Robinson, A.L.

    1982-01-01

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

  16. General relativistic fields of an isolated spin-half charged particle near the spin axis with application to the rest-mass of the electron and positron

    International Nuclear Information System (INIS)

    Lynch, J.T.

    1999-01-01

    Using a lowest-order approximation, the field equations of a general relativistic spinor-connection theory are solved semi-analytically for the fields of a stable, spin-half changed particle near the spin axis. With the exception of the atomic fine-structure constant, all parameters arising in the solution, including the rest mass of the source particle, are found by imposing the standard junction conditions of general relativity and electromagnetism. Using the empirical value for the fine-structure constant, the value derived for the rest mass gives some reason to identify the source particle with the electron. Moreover, since the rest mass is independent of the sign of the electron charge carried by the source, the solution is equally applicable to the positron

  17. Digital analysis of vibrations

    International Nuclear Information System (INIS)

    Bohnstedt, H.J.; Walter, G.

    1982-01-01

    Vibrational measurements, e.g. on turbomachinery, can be evaluated rapidly and economically with the aid of a combination of the following instruments: a desk-top computer, a two-channel vector filter and a FFT spectral analyzer. This equipment combination is available within the Allianz Centre for Technology and has also been used for mobile, on-site investigations during the last year. It enables calculation and display of time functions, kinetic shaft orbits, displacement diagrams. Bode plots, polar-coordinate plots, cascade diagrams and histograms. (orig.) [de

  18. Lattice Vibrations in Chlorobenzenes:

    DEFF Research Database (Denmark)

    Reynolds, P. A.; Kjems, Jørgen; White, J. W.

    1974-01-01

    Lattice vibrational dispersion curves for the ``intermolecular'' modes in the triclinic, one molecule per unit cell β phase of p‐C6D4Cl2 and p‐C6H4Cl2 have been obtained by inelastic neutron scattering. The deuterated sample was investigated at 295 and at 90°K and a linear extrapolation to 0°K...... was applied in order to correct for anharmonic effects. Calculations based on the atom‐atom model for van der Waals' interaction and on general potential parameters for the aromatic compounds agree reasonably well with the experimental observations. There is no substantial improvement in fit obtained either...

  19. Vibration control, machine diagnostics

    International Nuclear Information System (INIS)

    1990-01-01

    Changing vibrations announce damage in the form of wear or cracks on components of, e.g., engine rotors, pumps, power plant turbo sets, rounding-up tools, or marine diesel engines. Therefore, machine diagnostics use frequency analyses, system tests, trend analyses as well as expert systems to localize or estimate the causes of these damages and malfunctions. Data acquisistion, including not only sensors, but also reliable and redundant data processing systems and analyzing systems, play an important role. The lectures pertaining to the data base are covered in detail. (DG) [de

  20. The Effect of Upper Body Mass and Initial Knee Flexion on the Injury Outcome of Post Mortem Human Subject Pedestrian Isolated Legs.

    Science.gov (United States)

    Petit, Philippe; Trosseille, Xavier; Dufaure, Nicolas; Dubois, Denis; Potier, Pascal; Vallancien, Guy

    2014-11-01

    In the ECE 127 Regulation on pedestrian leg protection, as well as in the Euro NCAP test protocol, a legform impactor hits the vehicle at the speed of 40 kph. In these tests, the knee is fully extended and the leg is not coupled to the upper body. However, the typical configuration of a pedestrian impact differs since the knee is flexed during most of the gait cycle and the hip joint applies an unknown force to the femur. This study aimed at investigating the influence of the inertia of the upper body (modelled using an upper body mass fixed at the proximal end of the femur) and the initial knee flexion angle on the lower limb injury outcome. In total, 18 tests were conducted on 18 legs from 9 Post Mortem Human Subjects (PMHS). The principle of these tests was to impact the leg at 40 kph using a sled equipped with 3 crushing steel tubes, the stiffness of which were representative of the front face of a European sedan (bonnet leading edge, bumper and spoiler). The mass of the equipped sled was 74.5 kg. The test matrix was designed to perform 4 tests in 4 configurations combining two upper body masses (either 0 or 3 kg) and two knee angles (0 or 20 degrees) at 40 kph (11 m/s) plus 2 tests at 9 m/s. Autopsies were performed on the lower limbs and an injury assessment was established. The findings of this study were first that the increase of the upper body mass resulted in more severe injuries, second that an initial flexion of the knee, corresponding to its natural position during the gait cycle, decreased the severity of the injuries, and third that based on the injury outcome, a test conducted with no upper body mass and the knee fully extended was as severe as a test conducted with a 3 kg upper body mass and an initial knee flexion of 20°.

  1. 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

  2. Flexural Free Vibrations of Multistep Nonuniform Beams

    Directory of Open Access Journals (Sweden)

    Guojin Tan

    2016-01-01

    Full Text Available This paper presents an exact approach to investigate the flexural free vibrations of multistep nonuniform beams. Firstly, one-step beam with moment of inertia and mass per unit length varying as I(x=α11+βxr+4 and m(x=α21+βxr was studied. By using appropriate transformations, the differential equation for flexural free vibration of one-step beam with variable cross section is reduced to a four-order differential equation with constant coefficients. According to different types of roots for the characteristic equation of four-order differential equation with constant coefficients, two kinds of modal shape functions are obtained, and the general solutions for flexural free vibration of one-step beam with variable cross section are presented. An exact approach to solve the natural frequencies and modal shapes of multistep beam with variable cross section is presented by using transfer matrix method, the exact general solutions of one-step beam, and iterative method. Numerical examples reveal that the calculated frequencies and modal shapes are in good agreement with the finite element method (FEM, which demonstrates the solutions of present method are exact ones.

  3. Using periodicity to mitigate ground vibration

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard

    2015-01-01

    Introduction of trenches, barriers and wave impeding blocks on the transmission path between a source and receiver can be used for mitigation of ground vibration. However, to be effective a barrier must have a depth of about one wavelength of the waves to be mitigated. Hence, while great reductions......: A soil with periodic stiffening (ground improvement) and a ground with periodic changes in the surface elevation obtained by artificial landscaping. By means of a two-dimensional finite-element model, the stiffness and mass matrices are determined for a single cell of the ground with horizonal...

  4. Both natural selection and isolation by distance explain phenotypic divergence in bill size and body mass between South Australian little penguin colonies.

    Science.gov (United States)

    Colombelli-Négrel, Diane

    2016-11-01

    Morphological variation between populations of the same species can arise as a response to genetic variation, local environmental conditions, or a combination of both. In this study, I examined small-scale geographic variation in bill size and body mass in little penguins ( Eudyptula minor ) across five breeding colonies in South Australia separated by penguin colonies.

  5. Isolated Mass-Forming IgG4-Related Cholangitis as an Initial Clinical Presentation of Systemic IgG4-Related Disease

    Directory of Open Access Journals (Sweden)

    Seokhwi Kim

    2016-07-01

    Full Text Available IgG4-related disease (IgG4-RD may involve multiple organs. Although it usually presents as diffuse organ involvement, localized mass-forming lesions have been occasionally encountered in pancreas. However, the same pattern has been seldom reported in biliary tract. A 61-year-old male showed a hilar bile duct mass with multiple enlarged lymph nodes in imaging studies and he underwent trisectionectomy under impression of cholangiocarcinoma. Gross examination revealed a mass-like lesion around hilar bile duct. Histopathologically, dense lymphoplasmacytic infiltration and storiform fibrosis were identified without evidence of malignancy. Immunohistochemical stain demonstrated rich IgG4-positive plasma cell infiltration. Follow-up imaging studies disclosed multiple enlarged lymph nodes with involvement of pancreas and perisplenic soft tissue. The lesions have been significantly reduced after steroid treatment, which suggests multi-organ involvement of systemic IgG4-RD. Here, we report an unusual localized mass-forming IgG4-related cholangitis as an initial presentation of IgG4-RD, which was biliary manifestation of systemic IgG4-related autoimmune disease.

  6. DIFFERENTIATION OF AEROMONAS ISOLATES OBTAINED FROM DRINKING WATER DISTRIBUTION SYSTEM USING MATRIX-ASSISTED LASER DESCRIPTION/IONIZATION-MASS SPECTROMETRY (MALDI-MS)

    Science.gov (United States)

    The genus Aeromonas is one of several medically significant genera that have gained prominence due to their evolving taxonomy and controversial role in human diseases. In this study, matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) was used to analyze the...

  7. Anharmonic Vibrations of an "Ideal" Hooke's Law Oscillator

    Science.gov (United States)

    Thomchick, John; McKelvey, J. P.

    1978-01-01

    Presents a model describing the vibrations of a mass connected to fixed supports by "ideal" Hooke's law springs which may serve as a starting point in the study of the properties of irons in a crystal undergoing soft mode activated transition. (SL)

  8. Vibrations in a Multi-Storey Lightweight Building Structure

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard; Kirkegaard, Poul Henning

    2013-01-01

    This paper provides a quantification of the changes in vibration level that can be expected in a lightweight multi-storey wooden building due to reduced connection stiffness or added nonstructural mass. Firstly, the impact of changes in the floor-to-wall connections is examined. Secondly, a study...

  9. 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’.

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

    Science.gov (United States)

    Tiwari, Vivek; Jonas, David M.

    2018-02-01

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

  11. Correlating the vibrational spectra of structurally related molecules: A spectroscopic measure of similarity.

    Science.gov (United States)

    Tao, Yunwen; Zou, Wenli; Cremer, Dieter; Kraka, Elfi

    2018-03-05

    Using catastrophe theory and the concept of a mutation path, an algorithm is developed that leads to the direct correlation of the normal vibrational modes of two structurally related molecules. The mutation path is defined by weighted incremental changes in mass and geometry of the molecules in question, which are successively applied to mutate a molecule into a structurally related molecule and thus continuously converting their normal vibrational spectra from one into the other. Correlation diagrams are generated that accurately relate the normal vibrational modes to each other by utilizing mode-mode overlap criteria and resolving allowed and avoided crossings of vibrational eigenstates. The limitations of normal mode correlation, however, foster the correlation of local vibrational modes, which offer a novel vibrational measure of similarity. It will be shown how this will open new avenues for chemical studies. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Evaluation of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry in comparison to rpoB gene sequencing for species identification of bloodstream infection staphylococcal isolates.

    Science.gov (United States)

    Spanu, T; De Carolis, E; Fiori, B; Sanguinetti, M; D'Inzeo, T; Fadda, G; Posteraro, B

    2011-01-01

    As a result of variable expression of biochemical characters, misidentification by conventional phenotypic means often occurs with clinical isolates belonging to Staphylococcus species. Therefore, we evaluated the use of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of 450 blood isolates of the most relevant staphylococcal species, using sequence analysis of the rpoB gene as the reference method. A correct species identification by MALDI-TOF was obtained in 99.3% (447/450), with only three isolates being misidentified. In addition, MALDI-TOF correctly identified all the staphylococcal subspecies studied, including Staphylococcus capitis subsp. capitis and subsp. urealyticus, Staphylococcus cohnii subsp. urealyticus, Staphylococcus hominis subsp. novobiosepticus and subsp. hominis, Staphylococcus saprophyticus subsp. saprophyticus, Staphylococcus schleiferi subsp. schleiferi and Staphylococcus sciuri subsp. sciuri. Thus, MALDI-TOF MS-based species identification of staphylococci can be routinely achieved without any substantial costs for consumables or the time needed for labour-intensive DNA sequence analysis. © 2010 The Authors. Journal Compilation © 2010 European Society of Clinical Microbiology and Infectious Diseases.

  13. Reduction of vibration forces transmitted from a radiator cooling fan to a vehicle body

    Science.gov (United States)

    Lim, Jonghyuk; Sim, Woojeong; Yun, Seen; Lee, Dongkon; Chung, Jintai

    2018-04-01

    This article presents methods for reducing transmitted vibration forces caused by mass unbalance of the radiator cooling fan during vehicle idling. To identify the effects of mass unbalance upon the vibration characteristics, vibration signals of the fan blades were experimentally measured both with and without an added mass. For analyzing the vibration forces transmitted to the vehicle body, a dynamic simulation model was established that reflected the vibration characteristics of the actual system. This process included a method described herein for calculating the equivalent stiffness and the equivalent damping of the shroud stators and rubber mountings. The dynamic simulation model was verified by comparing its results with experimental results of the radiator cooling fan. The dynamic simulation model was used to analyze the transmitted vibration forces at the rubber mountings. Also, a measure was established to evaluate the effects of varying the design parameters upon the transmitted vibration forces. We present design guidelines based on these analyses to reduce the transmitted vibration forces of the radiator cooling fan.

  14. Dynamic tire pressure sensor for measuring ground vibration.

    Science.gov (United States)

    Wang, Qi; McDaniel, James Gregory; Wang, Ming L

    2012-11-07

    This work presents a convenient and non-contact acoustic sensing approach for measuring ground vibration. This approach, which uses an instantaneous dynamic tire pressure sensor (DTPS), possesses the capability to replace the accelerometer or directional microphone currently being used for inspecting pavement conditions. By measuring dynamic pressure changes inside the tire, ground vibration can be amplified and isolated from environmental noise. In this work, verifications of the DTPS concept of sensing inside the tire have been carried out. In addition, comparisons between a DTPS, ground-mounted accelerometer, and directional microphone are made. A data analysis algorithm has been developed and optimized to reconstruct ground acceleration from DTPS data. Numerical and experimental studies of this DTPS reveal a strong potential for measuring ground vibration caused by a moving vehicle. A calibration of transfer function between dynamic tire pressure change and ground acceleration may be needed for different tire system or for more accurate application.

  15. Vibrational spectra of ordered perovskites

    NARCIS (Netherlands)

    Corsmit, A.F.; Hoefdraad, H.E.; Blasse, G.

    1972-01-01

    The vibrational spectra of the molecular M6+O6 (M = Mo, Te, W) group in ordered perovskites of the type Ba2M2+M6+O6 are reported. These groups have symmetry Oh, whereas their site symmetry is also Oh. An assignment of the internal vibrations is presented.

  16. Vibrations and Stability: Solved Problems

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003.......Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003....

  17. Ultrahigh-performance liquid chromatography-ion trap mass spectrometry characterization of the steroidal saponins of Dioscorea panthaica Prain et Burkill and its application for accelerating the isolation and structural elucidation of steroidal saponins.

    Science.gov (United States)

    Wang, Weihao; Zhao, Ye; Jing, Wenguang; Zhang, Jun; Xiao, Hui; Zha, Qin; Liu, An

    2015-03-01

    Dioscorea panthaica is a traditional Chinese medicinal herb used in the treatment of various physiological conditions, including cardiovascular disease, gastropathy and hypertension. Steroidal saponins (SS) are the main active ingredients of this herb and have effects on myocardial ischemia and cancer. The phytochemical evaluation of SS is both time-consuming and laborious, and the isolation and structural determination steps can be especially demanding. For this reason, the development of new methods to accelerate the processes involved in the identification, isolation and structural elucidation of SS is highly desirable. In this study, a new ultrahigh performance liquid chromatography-ion trap mass spectrometry (UHPLC-IT/MS(n)) method has been developed for the identification of the SS in D. panthaica Prain et Burkill. Notably, the current method can distinguish between spirostanol and furostanol-type compounds based on the fragmentation patterns observed by electrospray ionization-ion trap mass spectrometry (ESI-IT/MS(n)) analysis. UHPLC-IT/MS(n) was used to conduct a detailed investigation of the number, structural class and order of the sugar moieties in the sugar chains of the SS present in D. panthaica. The established fragmentation features were used to analyze the compounds found in the 65% ethanol fraction of the water extracts of D. panthaica. Twenty-three SS were identified, including 11 potential new compounds and six groups of isomers. Two of these newly identified SS were selected as representative examples, and their chemical structures were confirmed by (1)H and (13)C NMR analyses. This newly developed UHPLC-IT/MS(n) method therefore allowed for the efficient identification, isolation and structural determination of the SS in D. panthaica. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Optimal design of a beam-based dynamic vibration absorber using fixed-points theory

    Science.gov (United States)

    Hua, Yingyu; Wong, Waion; Cheng, Li

    2018-05-01

    The addition of a dynamic vibration absorber (DVA) to a vibrating structure could provide an economic solution for vibration suppressions if the absorber is properly designed and located onto the structure. A common design of the DVA is a sprung mass because of its simple structure and low cost. However, the vibration suppression performance of this kind of DVA is limited by the ratio between the absorber mass and the mass of the primary structure. In this paper, a beam-based DVA (beam DVA) is proposed and optimized for minimizing the resonant vibration of a general structure. The vibration suppression performance of the proposed beam DVA depends on the mass ratio, the flexural rigidity and length of the beam. In comparison with the traditional sprung mass DVA, the proposed beam DVA shows more flexibility in vibration control design because it has more design parameters. With proper design, the beam DVA's vibration suppression capability can outperform that of the traditional DVA under the same mass constraint. The general approach is illustrated using a benchmark cantilever beam as an example. The receptance theory is introduced to model the compound system consisting of the host beam and the attached beam-based DVA. The model is validated through comparisons with the results from Abaqus as well as the Transfer Matrix method (TMM) method. Fixed-points theory is then employed to derive the analytical expressions for the optimum tuning ratio and damping ratio of the proposed beam absorber. A design guideline is then presented to choose the parameters of the beam absorber. Comparisons are finally presented between the beam absorber and the traditional DVA in terms of the vibration suppression effect. It is shown that the proposed beam absorber can outperform the traditional DVA by following this proposed guideline.

  19. Low Cost Digital Vibration Meter.

    Science.gov (United States)

    Payne, W Vance; Geist, Jon

    2007-01-01

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

  20. Discrimination of Aspergillus isolates at the species and strain level by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry fingerprinting.

    Science.gov (United States)

    Hettick, Justin M; Green, Brett J; Buskirk, Amanda D; Kashon, Michael L; Slaven, James E; Janotka, Erika; Blachere, Francoise M; Schmechel, Detlef; Beezhold, Donald H

    2008-09-15

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to generate highly reproducible mass spectral fingerprints for 12 species of fungi of the genus Aspergillus and 5 different strains of Aspergillus flavus. Prior to MALDI-TOF MS analysis, the fungi were subjected to three 1-min bead beating cycles in an acetonitrile/trifluoroacetic acid solvent. The mass spectra contain abundant peaks in the range of 5 to 20kDa and may be used to discriminate between species unambiguously. A discriminant analysis using all peaks from the MALDI-TOF MS data yielded error rates for classification of 0 and 18.75% for resubstitution and cross-validation methods, respectively. If a subset of 28 significant peaks is chosen, resubstitution and cross-validation error rates are 0%. Discriminant analysis of the MALDI-TOF MS data for 5 strains of A. flavus using all peaks yielded error rates for classification of 0 and 5% for resubstitution and cross-validation methods, respectively. These data indicate that MALDI-TOF MS data may be used for unambiguous identification of members of the genus Aspergillus at both the species and strain levels.

  1. Vernalophrys algivore gen. nov., sp. nov. (Rhizaria: Cercozoa: Vampyrellida), a New Algal Predator Isolated from Outdoor Mass Culture of Scenedesmus dimorphus.

    Science.gov (United States)

    Gong, Yingchun; Patterson, David J; Li, Yunguang; Hu, Zixuan; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2015-06-15

    Microbial contamination is the main cause of loss of biomass yield in microalgal cultures, especially under outdoor environmental conditions. Little is known about the identities of microbial contaminants in outdoor mass algal cultures. In this study, a new genus and species of vampyrellid amoeba, Vernalophrys algivore, is described from cultures of Scenedesmus dimorphus in open raceway ponds and outdoor flat-panel photobioreactors. This vampyrellid amoeba was a significant grazer of Scenedesmus and was frequently associated with a very rapid decline in algal numbers. We report on the morphology, subcellular structure, feeding behavior, molecular phylogeny, and life cycle. The new amoeba resembles Leptophrys in the shape of trophozoites and pseudopodia and in the mechanism of feeding (mainly by engulfment). It possesses two distinctive regions in helix E10_1 (nucleotides 117 to 119, CAA) and E23_1 (nucleotides 522 and 523, AG) of the 18S rRNA gene. It did not form a monophyletic group with Leptophrys in molecular phylogenetic trees. We establish a new genus, Vernalophrys, with the type species Vernalophrys algivore. The occurrence, impact of the amoeba on mass culture of S. dimorphus, and means to reduce vampyrellid amoeba contamination in Scenedesmus cultures are addressed. The information obtained from this study will be useful for developing an early warning system and control measures for preventing or treating this contaminant in microalgal mass cultures. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  2. Simple Program to Investigate Hysteresis Damping Effect of Cross-Ties on Cables Vibration of Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    Panagis G. Papadopoulos

    2012-01-01

    Full Text Available A short computer program, fully documented, is presented, for the step-by-step dynamic analysis of isolated cables or couples of parallel cables of a cable-stayed bridge, connected to each other and possibly with the deck of the bridge, by very thin pretensioned wires (cross-ties and subjected to variation of their axial forces due to traffic or to successive pulses of a wind drag force. A simplified SDOF model, approximating the fundamental vibration mode, is adopted for every individual cable. The geometric nonlinearity of the cables is taken into account by their geometric stiffness, whereas the material nonlinearities of the cross-ties include compressive loosening, tensile yielding, and hysteresis stress-strain loops. Seven numerical experiments are performed. Based on them, it is observed that if two interconnected parallel cables have different dynamic characteristics, for example different lengths, thus different masses, weights, and geometric stiffnesses, too, or if one of them has a small additional mass, then a single pretensioned very thin wire, connecting them to each other and possibly with the deck of the bridge, proves effective in suppressing, by its hysteresis damping, the vibrations of the cables.

  3. Edgewise vibration control of wind turbine blades using roller and liquid dampers

    DEFF Research Database (Denmark)

    Zhang, Zili; Nielsen, Søren R.K.

    2014-01-01

    suppressing edgewise vibrations. The roller dampers are more volumetrically efficient due to the higher mass density of the steel comparing with the liquid. On the other hand, TLCDs have their advantage that it is easier to specify the optimum damping of the damper by changing the opening ratio of the orifice......This paper deals with the passive vibration control of edgewise vibrations by means of roller dampers and tuned liquid column dampers (TLCDs). For a rotating blade, the large centrifugal acceleration makes it possible to use roller dampers or TLCDs with rather small masses for effectively...

  4. Lattice vibration spectra. 16

    International Nuclear Information System (INIS)

    Lutz, H.D.; Willich, P.

    1977-01-01

    The FIR absorption spectra of pyrite type compounds RuS 2 , RuSsub(2-x)Sesub(x), RuSe 2 , RuTe 2 , OsS 2 , OsSe 2 , and PtP 2 as well as loellingite type phosphides FeP 2 , RuP 2 , and OsP 2 are reported. For RuS 2 , RuSe 2 , RuTe 2 , OsS 2 , and PtP 2 all of the five infrared allowed modes (k = 0) are observed. As a first result of a numerical normal coordinate treatment vibration forms of pyrite structure are communicated. The spectra show that lattice forces of corresponding sulfides, tellurides, and phosphides are about the same strength, but increase strongly by substitution of iron by ruthenium and especially of ruthenium by osmium. The lattice constants of the RuSsub(2-x)Sesub(x) solid solution obey Vegard's rule. (author)

  5. Formation of Isolated Zn Vacancies in ZnO Single Crystals by Absorption of Ultraviolet Radiation: A Combined Study Using Positron Annihilation, Photoluminescence, and Mass Spectroscopy

    Science.gov (United States)

    Khan, Enamul H.; Weber, Marc H.; McCluskey, Matthew D.

    2013-07-01

    Positron annihilation spectra reveal isolated zinc vacancy (VZn) creation in single-crystal ZnO exposed to 193-nm radiation at 100mJ/cm2 fluence. The appearance of a photoluminescence excitation peak at 3.18 eV in irradiated ZnO is attributed to an electronic transition from the VZn acceptor level at ˜100meV to the conduction band. The observed VZn density profile and hyperthermal Zn+ ion emission support zinc vacancy-interstitial Frenkel pair creation by exciting a wide 6.34 eV Zn-O antibonding state at 193-nm photon—a novel photoelectronic process for controlled VZn creation in ZnO.

  6. 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.

  7. 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.

  8. Signature of self-gravitation in vibrating mirror interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Geszti, Tamas [Department of Physics of Complex Systems, Eoetvoes University, Budapest (Hungary)

    2007-05-15

    If - according to the Newton-Schroedinger scheme - gravitation is a classical field and its source is the mean mass density, that provides a force of attraction between the Schroedinger cat partners of the vibrating mirror in the proposed Marshall et al.experiment. That force is observable in principle as a shift of the visibility revival frequency, with respect to the c.o.m. vibration frequency to be observed mechanically. The effect is of observable size if short-range gravity is much stronger than long-range gravity.

  9. Species identification of clinical isolates of anaerobic bacteria: a comparison of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems

    DEFF Research Database (Denmark)

    Justesen, Ulrik Stenz; Holm, Anette; Knudsen, Elisa

    2011-01-01

    We compared two matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems (Shimadzu/SARAMIS and Bruker) on a collection of consecutive clinically important anaerobic bacteria (n = 290). The Bruker system had more correct identifications to the species level...... (67.2% versus 49.0%), but also more incorrect identifications (7.9% versus 1.4%). The system databases need to be optimized to increase identification levels. However, MALDI-TOF MS in its present version seems to be a fast and inexpensive method for identification of most clinically important...

  10. Use of positive ion fast atom bombardment mass spectrometry for rapid identification of a bile alcohol glucuronide isolated from cerebrotendinous xanthomatosis patients

    International Nuclear Information System (INIS)

    Dayal, B.; Salen, G.; Tint, G.S.; Shefer, S.; Benz, S.W.

    1990-01-01

    The identification of a major biliary and plasma bile alcohol glucuronide, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol-3-0-beta-D-glucuronide, present in cerebrotendinous xanthomatosis (CTX) patients, was investigated by positive ion fast atom bombardment mass spectrometry (FAB-MS). The spectrum was characterized by abundant ions formed by attachment of a proton, [M + H]+, or of alkali ions, [M + Na]+ and [M + 39K]+, to the glucuronide salt. These ions allowed an unambiguous deduction of the molecular weight of the sample. It is suggested that FAB-MS could be used in the rapid diagnosis of CTX

  11. Experiments on active precision isolation with a smart conical adapter

    Science.gov (United States)

    Li, H.; Li, H. Y.; Chen, Z. B.; Tzou, H. S.

    2016-07-01

    Based on a conical shell adaptor, an active vibration isolator for vibration control of precision payload is designed and tested in this study. Flexible piezoelectric sensors and actuators are bonded on the adaptor surface for active vibration monitoring and control. The mathematical model of a piezoelectric laminated conical shell is derived and then optimal design of the actuators is performed for the first axial vibration mode of the isolation system. A scaled conical adaptor is manufactured with four MFC actuators laminating on its outer surface. Active vibration isolation efficiency is then evaluated on a vibration shaker. The control model is built in Matlab/Simulink and programmed into the dSPACE control board. Experimental results show that, the proposed active isolator is effective in vibration suppression of payloads with the negative velocity feedback control. In contrast, the amplitude responses increase with positive feedback control. Furthermore, the amplitude responses increases when time delay is added into the control signals, and gets the maximum when the delay is close to one quarter of one cycle time.

  12. Torsional vibrations of shafts of mechanical systems

    Science.gov (United States)

    Gulevsky, V. A.; Belyaev, A. N.; Trishina, T. V.

    2018-03-01

    The aim of the research is to compare the calculated dependencies for determining the equivalent rigidity of a mechanical system and to come to an agreement on the methods of compiling dynamic models for systems with elastic reducer couplings in applied and classical oscillation theories. As a result of the analysis, it was revealed that most of the damage in the mechanisms and their details is due to the appearance of oscillations due to the dynamic impact of various factors: shock and alternating loads, unbalanced parts of machines, etc. Therefore, the designer at the design stage, and the engineer in the process of operation should provide the possibility of regulating the oscillatory processes both in details and machines by means of creating rational designs, as well as the use of special devices such as vibration dampers, various vibrators with optimal characteristics. A method is proposed for deriving a formula for determining the equivalent stiffness of a double-mass oscillating system of a multistage reducer with elastic reducer links without taking into account the internal losses and inertia of its elements, which gives a result completely coinciding with the result obtained by the classical theory of small mechanical oscillations and allows eliminating formulas for reducing the moments of inertia of the flywheel masses and the stiffness of the shafts.

  13. OPTIMAL AUTOMOBILE MUFFLER VIBRATION AND NOISE ANALYSIS

    Directory of Open Access Journals (Sweden)

    Sujit Kumar Jha

    2013-06-01

    Full Text Available The muffler is the main part of the Automobile Exhaust System, consisting of fibrous and porous materials to absorb noise and vibrations. The exhaust gas mass coming from the engine can produce resonance, which may be the source of fatigue failure in the exhaust pipe due to the presence of continuous resonance. The modes on the muffler should be located away from the engine’s operating frequencies in order to minimise the resonance. The objective of this paper is to determine the frequencies that appear at the modes, which have the more adverse effect during the operation of the automobile. An impact test has been conducted by applying the force using a hard head hammer, and data generated have been used for plotting a graph of the transfer functions using MATLAB. Six points have been selected, namely 1, 2, 3, 4, 7, and 11 on the muffler for the impact test. The collected data from theses six points have been analysed for the addition of damping. Results suggests that increasing the mass increases the damping and lowers the modes of the transfer function. Further research will identify higher strength materials that can withstand the higher gas temperatures as well as the corrosion and erosion by the gas emitted from the engine. muffler, noise, vibration,modal analysis,

  14. Vibrational Spectroscopy of Ionic Liquids.

    Science.gov (United States)

    Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

    2017-05-24

    Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

  15. Earthquakes: Isolation, energy dissipation and control of vibrations of structures for nuclear and industrial facilities and buildings. Overview of lectures and papers of a seminar organized jointly with the Italian Working Group on Seismic Isolation (GLIS) and held in Capri, Italy, 23-25 August 1993

    International Nuclear Information System (INIS)

    1995-09-01

    This report summarizes the contributions to the seminar together with the main technical issues and conclusions. Particular attention is paid to contributions which provided new or updated information with respect to that given at the IAEA Specialists Meeting on Seismic Isolation Technology, held at San Jose (California, USA), 18-20 March 1992. Attention is also paid to the development and implementation of more recent but very promising innovative techniques for the reduction of seismic and other dynamic loads. 64 refs, 1 tab

  16. Earthquakes: Isolation, energy dissipation and control of vibrations of structures for nuclear and industrial facilities and buildings. Overview of lectures and papers of a seminar organized jointly with the Italian Working Group on Seismic Isolation (GLIS) and held in Capri, Italy, 23-25 August 1993

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    This report summarizes the contributions to the seminar together with the main technical issues and conclusions. Particular attention is paid to contributions which provided new or updated information with respect to that given at the IAEA Specialists Meeting on Seismic Isolation Technology, held at San Jose (California, USA), 18-20 March 1992. Attention is also paid to the development and implementation of more recent but very promising innovative techniques for the reduction of seismic and other dynamic loads. 64 refs, 1 tab.

  17. Effect of longitudinal vibration of fluid-filled pipe with elastic wall on sound transmission character

    Directory of Open Access Journals (Sweden)

    DONG Peng

    2017-01-01

    Full Text Available When one end of a fluid-filled pipe with an elastic wall is fixed and a harmonic force effect acts on the other end,a steady longitudinal vibration will be produced. Compared to the pipeline resonance mode,the amplitude of the steady longitudinal vibration of an elastic pipe is greater,and the effect on the sound is also greater. The study of the steady longitudinal vibration of pipes can better describe the effects of fluid-filled pipelines on the radiation sound field of the pipe opening. Through the contrast between the analysis calculation of the equivalent beam model and the experimental results,the accuracy of the equivalent beam model for the calculation of the steady longitudinal vibration of pipelines is verified,and a method of isolating the steady longitudinal vibration state is proposed and verified.

  18. Molecular vibrations the theory of infrared and Raman vibrational spectra

    CERN Document Server

    Wilson, E Bright; Cross, Paul C

    1980-01-01

    Pedagogical classic and essential reference focuses on mathematics of detailed vibrational analyses of polyatomic molecules, advancing from application of wave mechanics to potential functions and methods of solving secular determinant.

  19. Frequency Tuning of Vibration Absorber Using Topology Optimization

    Science.gov (United States)

    Harel, Swapnil Subhash

    A tuned mass absorber is a system for reducing the amplitude in one oscillator by coupling it to a second oscillator. If tuned correctly, the maximum amplitude of the first oscillator in response to a periodic driver will be lowered, and much of the vibration will be 'transferred' to the second oscillator. The tuned vibration absorber (TVA) has been utilized for vibration control purposes in many sectors of Civil/Automotive/Aerospace Engineering for many decades since its inception. Time and again we come across a situation in which a vibratory system is required to run near resonance. In the past, approaches have been made to design such auxiliary spring mass tuned absorbers for the safety of the structures. This research focuses on the development and optimization of continuously tuned mass absorbers as a substitute to the discretely tuned mass absorbers (spring- mass system). After conducting the study of structural behavior, the boundary condition and frequency to which the absorber is to be tuned are determined. The Modal analysis approach is used to determine mode shapes and frequencies. The absorber is designed and optimized using the topology optimization tool, which simultaneously designs, optimizes and tunes the absorber to the desired frequency. The tuned, optimized absorber, after post processing, is attached to the target structure. The number of the absorbers are increased to amplify bandwidth and thereby upgrade the safety of structure for a wide range of frequency. The frequency response analysis is carried out using various combinations of structure and number of absorber cell.

  20. Some problems of control of dynamical conditions of technological vibrating machines

    Science.gov (United States)

    Kuznetsov, N. K.; Lapshin, V. L.; Eliseev, A. V.

    2017-10-01

    The possibility of control of dynamical condition of the shakers that are designed for vibration treatment of parts interacting with granular media is discussed. The aim of this article is to develop the methodological basis of technology of creation of mathematical models of shake tables and the development of principles of formation of vibrational fields, estimation of their parameters and control of the structure vibration fields. Approaches to build mathematical models that take into account unilateral constraints, the relationships between elements, with the vibrating surface are developed. Methods intended to construct mathematical model of linear mechanical oscillation systems are used. Small oscillations about the position of static equilibrium are performed. The original method of correction of vibration fields by introduction of the oscillating system additional ties to the structure are proposed. Additional ties are implemented in the form of a mass-inertial device for changing the inertial parameters of the working body of the vibration table by moving the mass-inertial elements. The concept of monitoring the dynamic state of the vibration table based on the original measuring devices is proposed. Estimation for possible changes in dynamic properties is produced. The article is of interest for specialists in the field of creation of vibration technology machines and equipment.

  1. Performance Study of Diagonally Segmented Piezoelectric Vibration Energy Harvester

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Eun [Catholic Univ. of Daegu, Daegu (Korea, Republic of)

    2013-08-15

    This study proposes a piezoelectric vibration energy harvester composed of two diagonally segmented energy harvesting units. An auxiliary structural unit is attached to the tip of a host structural unit cantilevered to a vibrating base, where the two components have beam axes in opposite directions from each other and matched short-circuit resonant frequencies. Contrary to the usual observations in two resonant frequency-matched structures, the proposed structure shows little eigenfrequency separation and yields a mode sequence change between the first two modes. These lead to maximum power generation around a specific frequency. By using commercial finite element software, it is shown that the magnitude of the output power from the proposed vibration energy harvester can be substantially improved in comparison with those from conventional cantilevered energy harvesters with the same footprint area and magnitude of a tip mass.

  2. A low frequency vibration energy harvester using magnetoelectric laminate composite

    International Nuclear Information System (INIS)

    Ju, Suna; Chae, Song Hee; Choi, Yunhee; Lee, Seungjun; Ji, Chang-Hyeon; Lee, Hyang Woon

    2013-01-01

    In this paper, we present a vibration energy harvester using magnetoelectric laminate composite and a springless spherical permanent magnet as a proof mass. The harvester utilizes a freely movable spherical permanent magnet to transform external vibration into a time varying magnetic field applied to the magnetoelectric transducer. The laminate composite consists of a Ni–Mn–Ga-based MSMA (magnetic shape memory alloy) element and a PZT (lead zirconate titanate) plate. A proof-of-concept harvester has been fabricated and characterized at various input accelerations and frequencies. A maximum open circuit voltage of 1.18 V has been obtained in response to a 3g vibration at 17 Hz with the fabricated device. Moreover, a maximum output voltage of 10.24 V and output power of 4.1 μW have been achieved on a 950 Ω load, when the fabricated energy harvester was mounted on a smartphone and shaken by hand. (paper)

  3. Vibration Properties of a Steel-PMMA Composite Beam

    Directory of Open Access Journals (Sweden)

    Yuyang He

    2015-01-01

    Full Text Available A steel-polymethyl methacrylate (steel-PMMA beam was fabricated to investigate the vibration properties of a one-dimensional phononic crystal structure. The experimental system included an excitation system, a signal acquisition system, and a data analysis and processing system. When an excitation signal was exerted on one end of the beam, the signals of six response points were collected with acceleration sensors. Subsequent signal analysis showed that the beam was attenuated in certain frequency ranges. The lumped mass method was then used to calculate the bandgap of the phononic crystal beam to analyze the vibration properties of a beam made of two different materials. The finite element method was also employed to simulate the vibration of the phononic crystal beam, and the simulation results were consistent with theoretical calculations. The existence of the bandgap was confirmed experimentally and theoretically, which allows for the potential applications of phononic crystals, including wave guiding and filtering, in integrated structures.

  4. Putting a damper on drilling's bad vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Jardine, S [Sedco forex, Montrouge (France); Malone, D [Anadrill, Sugar Land, TX (United States); Sheppard, M [Schlumberger Cambridge Research, Cambridge (United Kingdom)

    1994-01-01

    Harmful drilling vibrations are costing the industry dearly. Three main vibration types (axial, torsional and transverse) are explained and its causes discussed. Technology exists to eliminate most vibrations, but requires more systematic deployment than is usual. Hardware that eliminates vibrations is reviewed, including downhole shock measurement, torque feedback shock guards and antiwhirl bits. 9 figs., 11 refs.

  5. 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.

  6. Nonlinear Vibration of Ladle Crane due to a Moving Trolley

    Directory of Open Access Journals (Sweden)

    Yunsheng Xin

    2018-01-01

    Full Text Available The structural vibration of the main beam of a crane causes fatigue damage and discomfort to the driver. The swing of the payload has an effect on positioning precision, especially for a ladle crane, and this directly affects production safety. To study the influence of system parameters on the vibration of a crane’s main beam and the angle of the payload, a system consisting of the main beam, trolley, payload, and cabin was constructed. A rigid-flexible coupling dynamic model of a moving trolley with a hanging payload that moves on the flexible main beam with a concentrated cabin mass is established, and the direct integration method is used to solve the nonlinear differential equations of system vibration, which are obtained through Lagrange’s equation. Then, the time domain responses of the flexible main beam, payload angle, and cabin vibration are obtained. The influences of the trolley running speed, quality of the payload, and quality and position of the cabin on the vibration of the main beam and payload angle are analyzed. The results indicate that the amplitude of the main beam is directly proportional to the quality of the trolley, payload, and cab; the position of the cabin is closer to the mid-span; the amplitude of the main beam is larger; the structural damping has some influence on the vibration of the main beam; and the swing angle of the payload is related to the maximum running speed of the trolley, acceleration time, and length of the wire rope. In order to reduce the vibration of the main beam and cabin, the connection stiffness of the cabin should be ensured during installation.

  7. Quantitative transporter proteomics by liquid chromatography with tandem mass spectrometry: addressing methodologic issues of plasma membrane isolation and expression-activity relationship.

    Science.gov (United States)

    Kumar, Vineet; Prasad, Bhagwat; Patilea, Gabriela; Gupta, Anshul; Salphati, Laurent; Evers, Raymond; Hop, Cornelis E C A; Unadkat, Jashvant D

    2015-02-01

    To predict transporter-mediated drug disposition using physiologically based pharmacokinetic models, one approach is to measure transport activity and relate it to protein expression levels in cell lines (overexpressing the transporter) and then scale these to via in vitro to in vivo extrapolation (IVIVE). This approach makes two major assumptions. First, that the expression of the transporter is predominantly in the plasma membrane. Second, that there is a linear correlation between expression level and activity of the transporter protein. The present study was conducted to test these two assumptions. We evaluated two commercially available kits that claimed to separate plasma membrane from other cell membranes. The Qiagen Qproteome kit yielded very little protein in the fraction purported to be the plasma membrane. The Abcam Phase Separation kit enriched the plasma membrane but did not separate it from other intracellular membranes. For the Abcam method, the expression level of organic anion-transporting polypeptides (OATP) 1B1/2B1 and breast cancer resistance protein (BCRP) proteins in all subcellular fractions isolated from cells or human liver tissue tracked that of Na⁺-K⁺ ATPase. Assuming that Na⁺-K⁺ ATPase is predominantly located in the plasma membrane, these data suggest that the transporters measured are also primarily located in the plasma membrane. Using short hairpin RNA, we created clones of cell lines with varying degrees of OATP1B1 or BCRP expression level. In these clones, transport activity of OATP1B1 or BCRP was highly correlated with protein expression level (r² > 0.9). These data support the use of transporter expression level data and activity data from transporter overexpressing cell lines for IVIVE of transporter-mediated disposition of drugs. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  8. Evaluation of MALDI-TOF mass spectrometry and MALDI BioTyper in comparison to 16S rDNA sequencing for the identification of bacteria isolated from Arctic sea water.

    Directory of Open Access Journals (Sweden)

    Anna Maria Timperio

    Full Text Available MALDI-TOF Mass Spectrometry in association with the MALDI BioTyper 3.1 software has been evaluated for the identification and classification of 45 Arctic bacteria isolated from Kandalaksha Bay (White Sea, Russia. The high reliability of this method has been already demonstrated, in clinical microbiology, by a number of studies showing high attribution concordance with other credited analyses. Recently, it has been employed also in other branches of microbiology with controversial performance. The phyloproteomic results reported in this study were validated with those obtained by the "gold standard" 16S rDNA analysis. Concordance between the two methods was 100% at the genus level, while at the species level it was 48%. These percentages appeared to be quite high compared with other studies regarding environmental bacteria. However, the performance of MALDI BioTyper changed in relation to the taxonomical group analyzed, reflecting known identification problems related to certain genera. In our case, attribution concordance for Pseudomonas species was rather low (29%, confirming the problematic taxonomy of this genus, whereas that of strains from other genera was quite high (> 60%. Among the isolates tested in this study, two strains (Exiguobacterium oxidotolerans and Pseudomonas costantinii were misidentified by MALDI BioTyper due to absence of reference spectra in the database. Accordingly, missing spectra were acquired for the database implementation.

  9. Evaluation of MALDI-TOF mass spectrometry and MALDI BioTyper in comparison to 16S rDNA sequencing for the identification of bacteria isolated from Arctic sea water.

    Science.gov (United States)

    Timperio, Anna Maria; Gorrasi, Susanna; Zolla, Lello; Fenice, Massimiliano

    2017-01-01

    MALDI-TOF Mass Spectrometry in association with the MALDI BioTyper 3.1 software has been evaluated for the identification and classification of 45 Arctic bacteria isolated from Kandalaksha Bay (White Sea, Russia). The high reliability of this method has been already demonstrated, in clinical microbiology, by a number of studies showing high attribution concordance with other credited analyses. Recently, it has been employed also in other branches of microbiology with controversial performance. The phyloproteomic results reported in this study were validated with those obtained by the "gold standard" 16S rDNA analysis. Concordance between the two methods was 100% at the genus level, while at the species level it was 48%. These percentages appeared to be quite high compared with other studies regarding environmental bacteria. However, the performance of MALDI BioTyper changed in relation to the taxonomical group analyzed, reflecting known identification problems related to certain genera. In our case, attribution concordance for Pseudomonas species was rather low (29%), confirming the problematic taxonomy of this genus, whereas that of strains from other genera was quite high (> 60%). Among the isolates tested in this study, two strains (Exiguobacterium oxidotolerans and Pseudomonas costantinii) were misidentified by MALDI BioTyper due to absence of reference spectra in the database. Accordingly, missing spectra were acquired for the database implementation.

  10. Vibration measurements of automobile catalyst

    Science.gov (United States)

    Aatola, Seppo

    1994-09-01

    Vibration of catalyst cell, which is inside the casing of the catalyst, is difficult to measure with usual measuring instrumentation. When catalyst is in use, there is hot exhaust gas flow though the catalyst cell and temperature of the cell is approximately +900 degree(s)C. Therefore non-contact Laser- Doppler-Vibrometer was used to measure vibration velocity of the catalyst cell. The laser beam was directed towards the cell through pipe which was put through and welded to the casing of the catalyst. The outer end of the pipe was screw down with a tempered class to prevent exhaust gas flow from the pipe. The inner end of the pipe was open and few millimeters away from the measuring point. Catalyst was attached to the engine with two ways, rigidly close to the engine and flexible under the engine. The engine was running in test bench under controlled conditions. Vibration measurements were carried out during constant running speeds of the engine. Vibration signals were captured and analyzed with FFT-analyzer. Vibration of catalyst cell was strongest at running speed of 5000 rpm, from 10 to 20 g (1 g equals 9.81 ms-2), when catalyst was attached rigidly close to the engine. At running speed of 3000 rpm, vibration of catalyst cell was from 2 to 3 g in most cases, when catalyst was attached either rigidly or flexible to the engine. It is estimated that in real life, i.e. when catalyst is attached to car with same engine, vibration of catalyst cell at running speed of 5000 rpm is somewhere between 1 and 10 g. At running speed of 3000 rpm, which may be more often used when driving car (car speed approximately 100 kmh-1), vibration of catalyst cell is probably few g's.

  11. Smart accelerometer. [vibration damage detection

    Science.gov (United States)

    Bozeman, Richard J., Jr. (Inventor)

    1994-01-01

    The invention discloses methods and apparatus for detecting vibrations from machines which indicate an impending malfunction for the purpose of preventing additional damage and allowing for an orderly shutdown or a change in mode of operation. The method and apparatus is especially suited for reliable operation in providing thruster control data concerning unstable vibration in an electrical environment which is typically noisy and in which unrecognized ground loops may exist.

  12. Vibrational excitation from heterogeneous catalysis

    International Nuclear Information System (INIS)

    Purvis, G.D. III; Redmon, M.J.; Woken, G. Jr.

    1979-01-01

    Classical trajectories have been used by numerous researchers to investigate the dynamics of exothermic chemical reactions (atom + diatom) with a view toward understanding what leads to vibrational excitation of the product molecule. Unlike these studies, the case where the reaction is catalyzed by a solid surface is considered. The trajectory studies indicate that there should be conditions under which considerable vibrational energy appears in the product molecules without being lost to the solid during the course of the reaction. 2 figures, 3 tables

  13. Vibrational Spectral Studies of Gemfibrozil

    Science.gov (United States)

    Benitta, T. Asenath; Balendiran, G. K.; James, C.

    2008-11-01

    The Fourier Transform Raman and infrared spectra of the crystallized drug molecule 5-(2,5-Dimethylphenoxy)-2,2-dimethylpentanoic acid (Gemfibrozil) have been recorded and analyzed. Quantum chemical computational methods have been employed using Gaussian 03 software package based on Hartree Fock method for theoretically modeling the grown molecule. The optimized geometry and vibrational frequencies have been predicted. Observed vibrational modes have been assigned with the aid of normal coordinate analysis.

  14. On the isolation of elemental carbon (EC) for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure

    Science.gov (United States)

    Currie, L. A.; Kessler, J. D.

    2005-10-01

    The primary objective of the research reported here has been the development of a hybrid reference material (RM) to serve as a test of accuracy for elemental carbon (EC) isotopic (14C) speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of "soot" (EC), the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust), showed a range of results, but since the "truth" was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC) of measurement validity (Currie et al., 2002). Components of the new Hybrid RM (DiesApple), however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically). NIST SRM 2975 (Forklift Diesel Soot) has little or no 14C, and its major compositional component is EC; SRM 1515 (Apple Leaves) has the 14C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char) from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure. The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK) and thermal optical transmission (TOT) methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS). As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1) both methods exhibited biomass-C "leakage"; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC) isolated contained about 3% of the original biomass-C.; (2) the initial isothermal oxidation stage of

  15. On the isolation of elemental carbon (EC for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK EC isolation procedure

    Directory of Open Access Journals (Sweden)

    L. A. Currie

    2005-01-01

    Full Text Available The primary objective of the research reported here has been the development of a hybrid reference material (RM to serve as a test of accuracy for elemental carbon (EC isotopic (14C speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of 'soot' (EC, the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust, showed a range of results, but since the 'truth' was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC of measurement validity (Currie et al., 2002. Components of the new Hybrid RM (DiesApple, however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically. NIST SRM 2975 (Forklift Diesel Soot has little or no 14C, and its major compositional component is EC; SRM 1515 (Apple Leaves has the 14C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure. The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK and thermal optical transmission (TOT methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS. As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1 both methods exhibited biomass-C 'leakage'; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC isolated contained about 3% of the original biomass-C.; (2 the initial isothermal oxidation stage

  16. Elbow joint position sense after neuromuscular training with handheld vibration.

    Science.gov (United States)

    Tripp, Brady L; Faust, Donald; Jacobs, Patrick

    2009-01-01

    Clinicians use neuromuscular control exercises to enhance joint position sense (JPS); however, because standardizing such exercises is difficult, validations of their use are limited. To evaluate the acute effects of a neuromuscular training exercise with a handheld vibrating dumbbell on elbow JPS acuity. Crossover study. University athletic training research laboratory. Thirty-one healthy, college-aged volunteers (16 men, 15 women, age = 23 + or - 3 years, height = 173 + or - 8 cm, mass = 76 + or - 14 kg). We measured and trained elbow JPS using an electromagnetic tracking device that provided auditory and visual biofeedback. For JPS testing, participants held a dumbbell and actively identified the target elbow flexion angle (90 degrees ) using the software-generated biofeedback, followed by 3 repositioning trials without feedback. Each neuromuscular training protocol included 3 exercises during which participants held a 2.55-kg dumbbell vibrating at 15, 5, or 0 Hz and used software-generated biofeedback to locate and maintain the target elbow flexion angle for 15 seconds. We calculated absolute (accuracy) and variable (variability) errors using the differences between target and reproduced angles. Training protocols using 15-Hz vibration enhanced accuracy and decreased variability of elbow JPS (P or = .200). Our results suggest these neuromuscular control exercises, which included low-magnitude, low-frequency handheld vibration, may enhance elbow JPS. Future researchers should examine vibration of various durations and frequencies, should include injured participants and functional multijoint and multiplanar measures, and should examine long-term effects of training protocols on JPS and injury.

  17. Investigation of Gas Holdup in a Vibrating Bubble Column

    Science.gov (United States)

    Mohagheghian, Shahrouz; Elbing, Brian

    2015-11-01

    Synthetic fuels are part of the solution to the world's energy crisis and climate change. Liquefaction of coal during the Fischer-Tropsch process in a bubble column reactor (BCR) is a key step in production of synthetic fuel. It is known from the 1960's that vibration improves mass transfer in bubble column. The current study experimentally investigates the effect that vibration frequency and amplitude has on gas holdup and bubble size distribution within a bubble column. Air (disperse phase) was injected into water (continuous phase) through a needle shape injector near the bottom of the column, which was open to atmospheric pressure. The air volumetric flow rate was measured with a variable area flow meter. Vibrations were generated with a custom-made shaker table, which oscillated the entire column with independently specified amplitude and frequency (0-30 Hz). Geometric dependencies can be investigated with four cast acrylic columns with aspect ratios ranging from 4.36 to 24, and injector needle internal diameters between 0.32 and 1.59 mm. The gas holdup within the column was measured with a flow visualization system, and a PIV system was used to measure phase velocities. Preliminary results for the non-vibrating and vibrating cases will be presented.

  18. Isolated galaxies

    International Nuclear Information System (INIS)

    Einasto, Maret

    1990-01-01

    To test for the possible presence of really isolated galaxies, which form a randomly distributed population in voids, we compare the distribution of most isolated galaxies in an observed sample with distributions of the same number of random points using the nearest neighbour test. The results show that the random population of really isolated galaxies does not exist - even the most isolated galaxies are connected with systems of galaxies, forming their outlying parts. (author)

  19. Numerical optimization approach for resonant electromagnetic vibration transducer designed for random vibration

    International Nuclear Information System (INIS)

    Spreemann, Dirk; Hoffmann, Daniel; Folkmer, Bernd; Manoli, Yiannos

    2008-01-01

    This paper presents a design and optimization strategy for resonant electromagnetic vibration energy harvesting devices. An analytic expression for the magnetic field of cylindrical permanent magnets is used to build up an electromagnetic subsystem model. This subsystem is used to find the optimal resting position of the oscillating mass and to optimize the geometrical parameters (shape and size) of the magnet and coil. The objective function to be investigated is thereby the maximum voltage output of the transducer. An additional mechanical subsystem model based on well-known equations describing the dynamics of spring–mass–damper systems is established to simulate both nonlinear spring characteristics and the effect of internal limit stops. The mechanical subsystem enables the identification of optimal spring characteristics for realistic operation conditions such as stochastic vibrations. With the overall transducer model, a combination of both subsystems connected to a simple electrical circuit, a virtual operation of the optimized vibration transducer excited by a measured random acceleration profile can be performed. It is shown that the optimization approach results in an appreciable increase of the converter performance

  20. Development of a variable stiffness and damping tunable vibration isolator

    CSIR Research Space (South Africa)

    Cronje, JM

    2005-03-01

    Full Text Available the amplification at resonance. A practical variable stiffness spring was developed by using a compound leaf spring with circular spring elements. A wax actuator, controlled by a hot-air gun with a closed-loop displacement and velocity feedback control system...

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  2. Proteoglycan isolation and analysis

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    2001-01-01

    Proteoglycans can be difficult molecules to isolate and analyze due to large mass, charge, and tendency to aggregate or form macromolecular complexes. This unit describes detailed methods for purification of matrix, cell surface, and cytoskeleton-linked proteoglycans. Methods for analysis...

  3. Torsional Vibration of a Shafting System under Electrical Disturbances

    Directory of Open Access Journals (Sweden)

    Ling Xiang

    2012-01-01

    Full Text Available Torsional vibration responses of a nonlinear shafting system are studied by a modified Riccati torsional transfer matrix combining with the Newmark-β method. Firstly, the system is modeled as a chain consisting of an elastic spring with concentrated mass points, from which a multi-segment lumped mass model is established. Secondly, accumulated errors are eliminated from the eigenfrequencies and responses of the system's torsional vibration by this newly developed procedure. The incremental transfer matrix method, combining the modified Riccati torsional transfer matrix with Newmark-β method, is further applied to solve the dynamical equations for the torsional vibration of the nonlinear shafting system. Lastly, the shafting system of a turbine-generator is employed as an illustrating example, and simulation analysis has been performed on the transient responses of the shaft's torsional vibrations during typical power network disturbances, such as three-phase short circuit, two-phase short circuit and asynchronous juxtaposition. The results validate the present method and are instructive for the design of a turbo-generator shaft.

  4. Vibrational spectroscopy of proteins

    International Nuclear Information System (INIS)

    Schwaighofer, A.

    2013-01-01

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

  5. Electrostatic energy harvesting device with dual resonant structure for wideband random vibration sources at low frequency.

    Science.gov (United States)

    Zhang, Yulong; Wang, Tianyang; Zhang, Ai; Peng, Zhuoteng; Luo, Dan; Chen, Rui; Wang, Fei

    2016-12-01

    In this paper, we present design and test of a broadband electrostatic energy harvester with a dual resonant structure, which consists of two cantilever-mass subsystems each with a mass attached at the free edge of a cantilever. Comparing to traditional devices with single resonant frequency, the proposed device with dual resonant structure can resonate at two frequencies. Furthermore, when one of the cantilever-masses is oscillating at resonance, the vibration amplitude is large enough to make it collide with the other mass, which provides strong mechanical coupling between the two subsystems. Therefore, this device can harvest a decent power output from vibration sources at a broad frequency range. During the measurement, continuous power output up to 6.2-9.8 μW can be achieved under external vibration amplitude of 9.3 m/s 2 at a frequency range from 36.3 Hz to 48.3 Hz, which means the bandwidth of the device is about 30% of the central frequency. The broad bandwidth of the device provides a promising application for energy harvesting from the scenarios with random vibration sources. The experimental results indicate that with the dual resonant structure, the vibration-to-electricity energy conversion efficiency can be improved by 97% when an external random vibration with a low frequency filter is applied.

  6. Vibration properties of a rotating piezoelectric energy harvesting device that experiences gyroscopic effects

    Science.gov (United States)

    Lu, Haohui; Chai, Tan; Cooley, Christopher G.

    2018-03-01

    This study investigates the vibration of a rotating piezoelectric device that consists of a proof mass that is supported by elastic structures with piezoelectric layers. Vibration of the proof mass causes deformation in the piezoelectric structures and voltages to power the electrical loads. The coupled electromechanical equations of motion are derived using Newtonian mechanics and Kirchhoff's circuit laws. The free vibration behavior is investigated for devices with identical (tuned) and nonidentical (mistuned) piezoelectric support structures and electrical loads. These devices have complex-valued, speed-dependent eigenvalues and eigenvectors as a result of gyroscopic effects caused by their constant rotation. The characteristics of the complex-valued eigensolutions are related to physical behavior of the device's vibration. The free vibration behaviors differ significantly for tuned and mistuned devices. Due to gyroscopic effects, the proof mass in the tuned device vibrates in either forward or backward decaying circular orbits in single-mode free response. This is proven analytically for all tuned devices, regardless of the device's specific parameters or operating speed. For mistuned devices, the proof mass has decaying elliptical forward and backward orbits. The eigenvalues are shown to be sensitive to changes in the electrical load resistances. Closed-form solutions for the eigenvalues are derived for open and close circuits. At high rotation speeds these devices experience critical speeds and instability.

  7. Mass loss from Eta Carinae

    International Nuclear Information System (INIS)

    Andriesse, C.D.; Viotti, R.

    1979-01-01

    This high luminosity (5x10 6 solar luminosity) star since 1840 is losing mass at the rate of 7.5x10 -2 solar masses per year. The large mass loss could be the result of vibrational instabilities produced in the CNO hydrogen burning phase of a very massive (160 solar masses) star. The presence of high excitation lines in the ultraviolet spectrum of Eta Car suggests the idea of a hot zone excited by dissipation of the supersonic turbulent flow. (Auth.)

  8. Adaptive learning algorithms for vibration energy harvesting

    International Nuclear Information System (INIS)

    Ward, John K; Behrens, Sam

    2008-01-01

    By scavenging energy from their local environment, portable electronic devices such as MEMS devices, mobile phones, radios and wireless sensors can achieve greater run times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources such as human movement, wind, seismic forces and traffic. Existing approaches to vibration energy harvesting typically utilize a rectifier circuit, which is tuned to the resonant frequency of the harvesting structure and the dominant frequency of vibration. We have developed a novel approach to vibration energy harvesting, including adaptation to non-periodic vibrations so as to extract the maximum amount of vibration energy available. Experimental results of an experimental apparatus using an off-the-shelf transducer (i.e. speaker coil) show mechanical vibration to electrical energy conversion efficiencies of 27–34%

  9. Nonlinear damping based semi-active building isolation system

    Science.gov (United States)

    Ho, Carmen; Zhu, Yunpeng; Lang, Zi-Qiang; Billings, Stephen A.; Kohiyama, Masayuki; Wakayama, Shizuka

    2018-06-01

    Many buildings in Japan currently have a base-isolation system with a low stiffness that is designed to shift the natural frequency of the building below the frequencies of the ground motion due to earthquakes. However, the ground motion observed during the 2011 Tohoku earthquake contained strong long-period waves that lasted for a record length of 3 min. To provide a novel and better solution against the long-period waves while maintaining the performance of the standard isolation range, the exploitation of the characteristics of nonlinear damping is proposed in this paper. This is motivated by previous studies of the authors, which have demonstrated that nonlinear damping can achieve desired performance over both low and high frequency regions and the optimal nonlinear damping force can be realized by closed loop controlled semi-active dampers. Simulation results have shown strong vibration isolation performance on a building model with identified parameters and have indicated that nonlinear damping can achieve low acceleration transmissibilities round the structural natural frequency as well as the higher ground motion frequencies that have been frequently observed during most earthquakes in Japan. In addition, physical building model based laboratory experiments are also conducted, The results demonstrate the advantages of the proposed nonlinear damping technologies over both traditional linear damping and more advanced Linear-Quadratic Gaussian (LQG) feedback control which have been used in practice to address building isolation system design and implementation problems. In comparison with the tuned-mass damper and other active control methods, the proposed solution offers a more pragmatic, low-cost, robust and effective alternative that can be readily installed into the base-isolation system of most buildings.

  10. PC based vibration monitoring system

    International Nuclear Information System (INIS)

    Jain, Sanjay K.; Roy, D.A.; Pithawa, C.K.; Patil, R.K.

    2004-01-01

    Health of large rotating machinery gets reflected in the vibration signature of the rotor and supporting structures and proper recording of these signals and their analysis can give a clear picture of the health of the machine. Using these data and their trending, it is possible to predict an impending trouble in the machine so that preventive action can be taken in time and catastrophic failure can be avoided. Continuous monitoring and analysis can give quick warning and enable operator to take preventive measures. Reactor Control Division, BARC is developing a PC based Vibration monitoring system for turbo generator machinery. The System can acquire 20 vibration signals at a rate of 5000 samples per second and also 15 process signals at a rate of 100 samples/ sec. The software for vibration monitoring system includes acquisition modules, analysis modules and Graphical User Interface module. The acquisition module involves initialization, setting of required parameters and acquiring the data from PC-based data acquisition cards. The acquired raw vibration data is then stored for analysis using various software packages. The display and analysis of acquired data is done in LabVIEW 7.0 where the data is displayed in time as well as frequency domain along with the RMS value of the signal. (author)

  11. Extracellular mass transport considerations for space flight research concerning suspended and adherent in vitro cell cultures.

    Science.gov (United States)

    Klaus, David M; Benoit, Michael R; Nelson, Emily S; Hammond, Timmothy G

    2004-03-01

    Conducting biological research in space requires consideration be given to isolating appropriate control parameters. For in vitro cell cultures, numerous environmental factors can adversely affect data interpretation. A biological response attributed to microgravity can, in theory, be explicitly correlated to a specific lack of weight or gravity-driven motion occurring to, within or around a cell. Weight can be broken down to include the formation of hydrostatic gradients, structural load (stress) or physical deformation (strain). Gravitationally induced motion within or near individual cells in a fluid includes sedimentation (or buoyancy) of the cell and associated shear forces, displacement of cytoskeleton or organelles, and factors associated with intra- or extracellular mass transport. Finally, and of particular importance for cell culture experiments, the collective effects of gravity must be considered for the overall system consisting of the cells, their environment and the device in which they are contained. This does not, however, rule out other confounding variables such as launch acceleration, on orbit vibration, transient acceleration impulses or radiation, which can be isolated using onboard centrifuges or vibration isolation techniques. A framework is offered for characterizing specific cause-and-effect relationships for gravity-dependent responses as a function of the above parameters.

  12. Model reduction and analysis of a vibrating beam microgyroscope

    KAUST Repository

    Ghommem, Mehdi; Nayfeh, Ali Hasan; Choura, Slim A.

    2012-01-01

    The present work is concerned with the nonlinear dynamic analysis of a vibrating beam microgyroscope composed of a rotating cantilever beam with a tip mass at its end. The rigid mass is coupled to two orthogonal electrodes in the drive and sense directions, which are attached to the rotating base. The microbeam is driven by an AC voltage in the drive direction, which induces vibrations in the orthogonal sense direction due to rotation about the microbeam axis. The electrode placed in the sense direction is used to measure the induced motions and extract the underlying angular speed. A reduced-order model of the gyroscope is developed using the method of multiple scales and used to examine its dynamic behavior. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  13. MEMS-based thick film PZT vibrational energy harvester

    DEFF Research Database (Denmark)

    Lei, Anders; Xu, Ruichao; Thyssen, Anders

    2011-01-01

    We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using a mechan......We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using...... a mechanical front side protection of an SOI wafer with screen printed PZT thick film. The fabricated harvester device produces 14.0 μW with an optimal resistive load of 100 kΩ from 1g (g=9.81 m s-2) input acceleration at its resonant frequency of 235 Hz....

  14. Model reduction and analysis of a vibrating beam microgyroscope

    KAUST Repository

    Ghommem, Mehdi

    2012-05-08

    The present work is concerned with the nonlinear dynamic analysis of a vibrating beam microgyroscope composed of a rotating cantilever beam with a tip mass at its end. The rigid mass is coupled to two orthogonal electrodes in the drive and sense directions, which are attached to the rotating base. The microbeam is driven by an AC voltage in the drive direction, which induces vibrations in the orthogonal sense direction due to rotation about the microbeam axis. The electrode placed in the sense direction is used to measure the induced motions and extract the underlying angular speed. A reduced-order model of the gyroscope is developed using the method of multiple scales and used to examine its dynamic behavior. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  15. The low frequency 2D vibration sensor based on flat coil element

    Energy Technology Data Exchange (ETDEWEB)

    Djamal, Mitra; Sanjaya, Edi; Islahudin; Ramli [Department of Physics, Institut Teknologi Bandung, Jl. Ganesa 10 Bandung 40116 (Indonesia); Department of Physics, Institut Teknologi Bandung, Jl. Ganesa 10 Bandung 40116 (Indonesia) and Department of Physics, UIN Syarif Hidayatullah, Jl. Ir.H. Djuanda 95 Ciputat 15412 (Indonesia); MTs NW Nurul Iman Kembang Kerang, Jl. Raya Mataram - Lb.Lombok, NTB (Indonesia); Department of Physics, Institut Teknologi Bandung, Jl. Ganesa 10 Bandung 40116 (Indonesia) and Department of Physics,Universitas Negeri Padang, Jl. Prof. Hamka, Padang 25132 (Indonesia)

    2012-06-20

    Vibration like an earthquake is a phenomenon of physics. The characteristics of these vibrations can be used as an early warning system so as to reduce the loss or damage caused by earthquakes. In this paper, we introduced a new type of low frequency 2D vibration sensor based on flat coil element that we have developed. Its working principle is based on position change of a seismic mass that put in front of a flat coil element. The flat coil is a part of a LC oscillator; therefore, the change of seismic mass position will change its resonance frequency. The results of measurements of low frequency vibration sensor in the direction of the x axis and y axis gives the frequency range between 0.2 to 1.0 Hz.

  16. Induced vibrations increase performance of a winged self-righting robot

    Science.gov (United States)

    Othayoth, Ratan; Xuan, Qihan; Li, Chen

    When upside down, cockroaches can open their wings to dynamically self-right. In this process, an animal often has to perform multiple unsuccessful maneuvers to eventually right, and often flails its legs. Here, we developed a cockroach-inspired winged self-righting robot capable of controlled body vibrations to test the hypothesis that vibrations assist self-righting transitions. Robot body vibrations were induced by an oscillating mass (10% of body mass) and varied by changing oscillation frequency. We discovered that, as the robot's body vibrations increased, righting probability increased, and righting time decreased (P locomotor transitions, but highlights the need for further stochastic modeling to capture the uncertain nature of when righting maneuvers result in successful righting.

  17. Vibration tests on single heat exchanger tubes in air and static water

    International Nuclear Information System (INIS)

    Collinson, A.E.; Warneford, I.P.

    1978-07-01

    The vibrational characteristics of a 7 span straight tube and a 26 span U-tube have been investigated for the effects of fluid medium (air/water), tube-grid clearance, tube-grid contact force, vibration transmission and scale. Measured frequency response and mode shapes compared favourably with theoretical values, vibration with pin-pin tube support being most readily excited. The frequency reduction on immersion in water corresponded to an added mass equivalent to the liquid displaced mass. Dynamic magnifiers varied in the range 12 to 135 with mean values of 30 to 40 in water and 45 to 60 in air. Principal vibration modes and damping values were reproducible in a half-scale model of a U-tube. (author)

  18. Rapid prototyping tool for tuning of vibration absorbers; Rapid-Prototyping-Tool zur Abstimmung von Schwingungstilgern

    Energy Technology Data Exchange (ETDEWEB)

    Marienfeld, P.M.; Karkosch, H.J. [ContiTech Vibration Control GmbH, Hannover (Germany); Bohn, C. [Technische Univ. Clausthal (Germany); Svaricek, F. [Univ. der Bundeswehr Muenchen (Germany); Knake-Langhorst, S. [Deutsches Zentrum fuer Luft- und Raumfahrt, Braunschweig (Germany)

    2008-07-01

    In the automotive industry passive vibration absorbers are a well established method to reduce structural vibrations in automotive vehicles. Designing a vibration absorber consists of selecting its mechanical properties. Usually extensive tests are necessary with different absorbers in the vehicle and subjective as well as objective evaluation of the results. This requires hardware modifications between different tests. In this paper, an approach is proposed that can assist in the development of vibration absorbers. It is based on tuning an active vibration control system such that it reproduces the behavior of a specified vibration absorber. This behavior can then be changed electronically without modifying the hardware. Two different control approaches are compared. In the first approach, the apparent physical properties of a vibration absorber are directly modified through acceleration, velocity or displacement feedback. In the second approach, a desired dynamic mass transfer function for the vibration absorber is prescribed and an H2-norm optimal model matching problem is solved. Experimental results obtained with this approach are presented. (orig.)

  19. 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.

  20. An innovative MRE absorber with double natural frequencies for wide frequency bandwidth vibration absorption

    International Nuclear Information System (INIS)

    Sun, Shuaishuai; Yang, Jian; Li, Weihua; Alici, Gursel; Deng, Huaxia; Du, Haiping; Yan, Tianhong

    2016-01-01

    A new design of adaptive tuned vibration absorber was proposed in this study for vibration reduction. The innovation of the new absorber is the adoption of the eccentric mass on the top of the multilayered magnetorheological elastomer (MRE) structure so that this proposed absorber has two vibration modes: one in the torsional direction and the other in translational direction. This property enables the absorber to expand its effective bandwidth and to be more capable of reducing the vibrations especially dealing with those vibrations with multi-frequencies. The innovative MRE absorber was designed and tested on a horizontal vibration table. The test results illustrate that the MRE absorber realized double natural frequencies, both of which are controllable. Inertia’s influence on the dynamic behavior of the absorber is also investigated in order to guide the design of the innovative MRE absorber. Additionally, the experimentally obtained natural frequencies coincide with the theoretical data, which sufficiently verifies the feasibility of this new design. The last part in terms of the vibration absorption ability also proves that both of these two natural frequencies play a great role in absorbing vibration energy. (paper)