Sample records for significant vibration reduction

  1. Vibration for Pain Reduction in a Plastic Surgery Clinic. (United States)

    Eichhorn, Mitchell George; Karadsheh, Murad Jehad; Krebiehl, Johanna Ruth; Ford, Dawn Marie; Ford, Ronald D


    Patients can experience significant pain during routine procedures in the plastic surgery clinic. Methods for clinical pain reduction are often impractical, time-consuming, or ineffective. Vibration is a safe, inexpensive, and highly applicable modality for pain reduction that can be readily utilized for a wide variety of procedures. This study evaluated the use of vibration as a viable pain-reduction strategy in the clinical plastic surgery setting. Patients requiring at least 2 consecutive procedures that are considered painful were enrolled in the study. These included injections, staple removal, and suture removal. In the same patient, one half of the procedures were performed without vibration and the other half with vibration. After completing the procedures, the patients rated their pain with vibration and without vibration. The patient and the researcher also described the experience with a short questionnaire. Twenty-eight patients were enrolled in the study. Patients reported significantly less pain on the Numeric Rating Scale pain scale when vibration was used compared with the control group (p reduction. It significantly reduces the pain experienced by patients during minor office procedures. Given its practicality and ease of use, it is a welcome tool in the plastic surgery clinic.

  2. Vibration Reduction System Using Magnetic Suspension Technology

    Directory of Open Access Journals (Sweden)

    Spychała Jarosław


    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.

  3. Application of system concept in vibration and noise reduction

    Directory of Open Access Journals (Sweden)

    SHENG Meiping


    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.


    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.

  5. Spectroscopic probes of vibrationally excited molecules at chemically significant energies

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, T.R. [Univ. of Rochester, NY (United States)


    This project involves the application of multiple-resonance spectroscopic techniques for investigating energy transfer and dissociation dynamics of highly vibrationally excited molecules. Two major goals of this work are: (1) to provide information on potential energy surfaces of combustion related molecules at chemically significant energies, and (2) to test theoretical modes of unimolecular dissociation rates critically via quantum-state resolved measurements.

  6. Rotor Vibration Reduction via Active Hybrid Bearings

    DEFF Research Database (Denmark)

    Nicoletti, Rodrigo; Santos, Ilmar


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

  7. Hydraulic elements in reduction of vibrations in mechanical systems (United States)

    Białas, K.; Buchacz, A.


    This work presents non-classical method of design of mechanic systems with subsystem reducing vibrations. The purpose of this paper is also introduces synthesis of mechanic system with reducing vibrations understand as design of this type of systems. The synthesis may be applied to modify the already existing systems in order to achieve a desired result. Elements which reduce vibrations can be constructed with passive, semi-active or active components. These considerations systems have selected active items. A hallmark of active elements it is possible to change the parameters on time of these elements and their power from an external source. The implementation of active elements is very broad. These elements can be implemented through the use of components of electrical, pneumatic, hydraulic, etc. The system was consisted from mechanical and hydraulic elements. Hydraulic elements were used as subsystem reducing unwanted vibration of mechanical system. Hydraulic elements can be realized in the form of hydraulic cylinder. In the case of an active vibration reduction in the form of hydraulic cylinder it is very important to find the corresponding values of hydraulic components. The values of these elements affect the frequency of vibrations of this sub-system which is related to the effective vibration reduction [7,11].

  8. Vibration of carbon nanotubes with defects: order reduction methods (United States)

    Hudson, Robert B.; Sinha, Alok


    Order reduction methods are widely used to reduce computational effort when calculating the impact of defects on the vibrational properties of nearly periodic structures in engineering applications, such as a gas-turbine bladed disc. However, despite obvious similarities these techniques have not yet been adapted for use in analysing atomic structures with inevitable defects. Two order reduction techniques, modal domain analysis and modified modal domain analysis, are successfully used in this paper to examine the changes in vibrational frequencies, mode shapes and mode localization caused by defects in carbon nanotubes. The defects considered are isotope defects and Stone-Wales defects, though the methods described can be extended to other defects.

  9. Reduction of the radiating sound of a submerged finite cylindrical shell structure by active vibration control. (United States)

    Kim, Heung Soo; Sohn, Jung Woo; Jeon, Juncheol; Choi, Seung-Bok


    In this work, active vibration control of an underwater cylindrical shell structure was investigated, to suppress structural vibration and structure-borne noise in water. Finite element modeling of the submerged cylindrical shell structure was developed, and experimentally evaluated. Modal reduction was conducted to obtain the reduced system equation for the active feedback control algorithm. Three Macro Fiber Composites (MFCs) were used as actuators and sensors. One MFC was used as an exciter. The optimum control algorithm was designed based on the reduced system equations. The active control performance was then evaluated using the lab scale underwater cylindrical shell structure. Structural vibration and structure-borne noise of the underwater cylindrical shell structure were reduced significantly by activating the optimal controller associated with the MFC actuators. The results provide that active vibration control of the underwater structure is a useful means to reduce structure-borne noise in water.

  10. Reduction of the Radiating Sound of a Submerged Finite Cylindrical Shell Structure by Active Vibration Control

    Directory of Open Access Journals (Sweden)

    Seung-Bok Choi


    Full Text Available In this work, active vibration control of an underwater cylindrical shell structure was investigated, to suppress structural vibration and structure-borne noise in water. Finite element modeling of the submerged cylindrical shell structure was developed, and experimentally evaluated. Modal reduction was conducted to obtain the reduced system equation for the active feedback control algorithm. Three Macro Fiber Composites (MFCs were used as actuators and sensors. One MFC was used as an exciter. The optimum control algorithm was designed based on the reduced system equations. The active control performance was then evaluated using the lab scale underwater cylindrical shell structure. Structural vibration and structure-borne noise of the underwater cylindrical shell structure were reduced significantly by activating the optimal controller associated with the MFC actuators. The results provide that active vibration control of the underwater structure is a useful means to reduce structure-borne noise in water.

  11. Active twist control methodology for vibration reduction of a helicopter with dissimilar rotor system

    International Nuclear Information System (INIS)

    Pawar, Prashant M; Jung, Sung Nam


    In this work, an active vibration reduction of hingeless composite rotor blades with dissimilarity is investigated using the active twist concept and the optimal control theory. The induced shear strain on the actuation mechanism by the piezoelectric constant d 15 from the PZN–8% PT-based single-crystal material is used to achieve more active twisting to suppress the extra vibrations. The optimal control algorithm is based on the minimization of an objective function comprised of quadratic functions of vibratory hub loads and voltage control harmonics. The blade-to-blade dissimilarity is modeled using the stiffness degradation of composite blades. The optimal controller is applied to various possible dissimilarities arising from different damage patterns of composite blades. The governing equations of motion are derived using Hamilton's principle. The effects of composite materials and smart actuators are incorporated into the comprehensive aeroelastic analysis system. Numerical results showing the impact of addressing the blade dissimilarities on hub vibrations and voltage inputs required to suppress the vibrations are demonstrated. It is observed that all vibratory shear forces are reduced considerably and the major harmonics of moments are reduced significantly. However, the controller needs further improvement to suppress 1/rev moment loads. A mechanism to achieve vibration reduction for the dissimilar rotor system has also been identified

  12. Active twist control methodology for vibration reduction of a helicopter with dissimilar rotor system (United States)

    Pawar, Prashant M.; Jung, Sung Nam


    In this work, an active vibration reduction of hingeless composite rotor blades with dissimilarity is investigated using the active twist concept and the optimal control theory. The induced shear strain on the actuation mechanism by the piezoelectric constant d15 from the PZN-8% PT-based single-crystal material is used to achieve more active twisting to suppress the extra vibrations. The optimal control algorithm is based on the minimization of an objective function comprised of quadratic functions of vibratory hub loads and voltage control harmonics. The blade-to-blade dissimilarity is modeled using the stiffness degradation of composite blades. The optimal controller is applied to various possible dissimilarities arising from different damage patterns of composite blades. The governing equations of motion are derived using Hamilton's principle. The effects of composite materials and smart actuators are incorporated into the comprehensive aeroelastic analysis system. Numerical results showing the impact of addressing the blade dissimilarities on hub vibrations and voltage inputs required to suppress the vibrations are demonstrated. It is observed that all vibratory shear forces are reduced considerably and the major harmonics of moments are reduced significantly. However, the controller needs further improvement to suppress 1/rev moment loads. A mechanism to achieve vibration reduction for the dissimilar rotor system has also been identified.

  13. Active Vibration Control for Helicopter Interior Noise Reduction Using Power Minimization (United States)

    Mendoza, J.; Chevva, K.; Sun, F.; Blanc, A.; Kim, S. B.


    This report describes work performed by United Technologies Research Center (UTRC) for NASA Langley Research Center (LaRC) under Contract NNL11AA06C. The objective of this program is to develop technology to reduce helicopter interior noise resulting from multiple gear meshing frequencies. A novel active vibration control approach called Minimum Actuation Power (MAP) is developed. MAP is an optimal control strategy that minimizes the total input power into a structure by monitoring and varying the input power of controlling sources. MAP control was implemented without explicit knowledge of the phasing and magnitude of the excitation sources by driving the real part of the input power from the controlling sources to zero. It is shown that this occurs when the total mechanical input power from the excitation and controlling sources is a minimum. MAP theory is developed for multiple excitation sources with arbitrary relative phasing for single or multiple discrete frequencies and controlled by a single or multiple controlling sources. Simulations and experimental results demonstrate the feasibility of MAP for structural vibration reduction of a realistic rotorcraft interior structure. MAP control resulted in significant average global vibration reduction of a single frequency and multiple frequency excitations with one controlling actuator. Simulations also demonstrate the potential effectiveness of the observed vibration reductions on interior radiated noise.

  14. Integral Twist Actuation of Helicopter Rotor Blades for Vibration Reduction (United States)

    Shin, SangJoon; Cesnik, Carlos E. S.


    Active integral twist control for vibration reduction of helicopter rotors during forward flight is investigated. The twist deformation is obtained using embedded anisotropic piezocomposite actuators. An analytical framework is developed to examine integrally-twisted blades and their aeroelastic response during different flight conditions: frequency domain analysis for hover, and time domain analysis for forward flight. Both stem from the same three-dimensional electroelastic beam formulation with geometrical-exactness, and axe coupled with a finite-state dynamic inflow aerodynamics model. A prototype Active Twist Rotor blade was designed with this framework using Active Fiber Composites as the actuator. The ATR prototype blade was successfully tested under non-rotating conditions. Hover testing was conducted to evaluate structural integrity and dynamic response. In both conditions, a very good correlation was obtained against the analysis. Finally, a four-bladed ATR system is built and tested to demonstrate its concept in forward flight. This experiment was conducted at NASA Langley Tansonic Dynamics Tunnel and represents the first-of-a-kind Mach-scaled fully-active-twist rotor system to undergo forward flight test. In parallel, the impact upon the fixed- and rotating-system loads is estimated by the analysis. While discrepancies are found in the amplitude of the loads under actuation, the predicted trend of load variation with respect to its control phase correlates well. It was also shown, both experimentally and numerically, that the ATR blade design has the potential for hub vibratory load reduction of up to 90% using individual blade control actuation. Using the numerical framework, system identification is performed to estimate the harmonic transfer functions. The linear time-periodic system can be represented by a linear time-invariant system under the three modes of blade actuation: collective, longitudinal cyclic, and lateral cyclic. A vibration

  15. Power flow prediction in vibrating systems via model reduction (United States)

    Li, Xianhui

    This dissertation focuses on power flow prediction in vibrating systems. Reduced order models (ROMs) are built based on rational Krylov model reduction which preserve power flow information in the original systems over a specified frequency band. Stiffness and mass matrices of the ROMs are obtained by projecting the original system matrices onto the subspaces spanned by forced responses. A matrix-free algorithm is designed to construct ROMs directly from the power quantities at selected interpolation frequencies. Strategies for parallel implementation of the algorithm via message passing interface are proposed. The quality of ROMs is iteratively refined according to the error estimate based on residual norms. Band capacity is proposed to provide a priori estimate of the sizes of good quality ROMs. Frequency averaging is recast as ensemble averaging and Cauchy distribution is used to simplify the computation. Besides model reduction for deterministic systems, details of constructing ROMs for parametric and nonparametric random systems are also presented. Case studies have been conducted on testbeds from Harwell-Boeing collections. Input and coupling power flow are computed for the original systems and the ROMs. Good agreement is observed in all cases.

  16. Identification and reduction of piping-vibrations in plants

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  17. Identification and reduction of piping-vibrations in plants

    International Nuclear Information System (INIS)

    Kerkhof, K.


    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.

  18. Environmental vibration reduction utilizing an array of mass scatterers

    DEFF Research Database (Denmark)

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


    .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...

  19. Reduction of vibrational interference from the iron core on HBTXIA

    International Nuclear Information System (INIS)

    Wilcock, P.D.


    The HBTXIA machine is a toroidal reversed field pinch which utilises a 1 volt second iron core. This paper looks briefly at the sources of vibration from the iron core and describes the design of a novel support system that has been installed to minimise the transmission of vibration to plasma diagnostics and other equipment during the machine pulse. Vibration measurements on the completed installation when the core is driven to saturation are reported and compared with calculations for a ground mounted core. (author)

  20. Active Vibration Reduction of the Advanced Stirling Convertor (United States)

    Wilson, Scott D.; Metscher, Jonathan F.; Schifer, Nicholas A.


    Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A Stirling Radioisotope Generator (SRG) could offer space missions a more efficient power system that uses one fourth of the nuclear fuel and decreases the thermal footprint compared to the current state of the art. The Stirling Cycle Technology Development (SCTD) Project is funded by the RPS Program to developing Stirling-based subsystems, including convertors and controller maturation efforts that have resulted in high fidelity hardware like the Advanced Stirling Radioisotope Generator (ASRG), Advanced Stirling Convertor (ASC), and ASC Controller Unit (ACU). The SCTD Project also performs research to develop less mature technologies with a wide variety of objectives, including increasing temperature capability to enable new environments, improving system reliability or fault tolerance, reducing mass or size, and developing advanced concepts that are mission enabling. Active vibration reduction systems (AVRS), or "balancers", have historically been developed and characterized to provide fault tolerance for generator designs that incorporate dual-opposed Stirling convertors or enable single convertor, or small RPS, missions. Balancers reduce the dynamic disturbance forces created by the power piston and displacer internal moving components of a single operating convertor to meet spacecraft requirements for induced disturbance force. To improve fault tolerance for dual-opposed configurations and enable single convertor configurations, a breadboard AVRS was implemented on the Advanced Stirling Convertor (ASC). The AVRS included a linear motor, a motor mount, and a closed-loop controller able to balance out the transmitted peak dynamic disturbance using acceleration feedback. Test objectives included quantifying power and mass penalty and reduction in transmitted force over a range of ASC

  1. Reduction method for residual stress of welded joint using random vibration

    International Nuclear Information System (INIS)

    Aoki, Shigeru; Nishimura, Tadashi; Hiroi, Tetsumaro


    Welded joints are used for construction of many structures. Residual stress is induced near the bead caused by locally given heat. Tensile residual stress on the surface may reduce fatigue strength. In this paper, a new method for reduction of residual stress using vibration during welding is proposed. As vibrational load, random vibration, white noise and filtered white noise are used. Two thin plates are butt-welded. Residual stress is measured with a paralleled beam X-ray diffractometer with scintillation counter after removing quenched scale chemically. It is concluded that tensile residual stress near the bead is reduced by using random vibration during welding

  2. A periodic piezoelectric smart structure with the integrated passive/active vibration-reduction performances (United States)

    Wang, Yuxi; Niu, Shengkai; Hu, Yuantai


    The paper proposes a new piezoelectric smart structure with the integrated passive/active vibration-reduction performances, which is made of a series of periodic structural units. Every structural unit is made of two layers, one is an array of piezoelectric bimorphs (PBs) and one is an array of metal beams (MBs), both are connected as a whole by a metal plate. Analyses show that such a periodic smart structure possesses two aspects of vibration-reduction performance: one comes from its phonon crystal characteristics which can isolate those vibrations with the driving frequency inside the band gap(s). The other one comes from the electromechanical conversion of bent PBs, which is actively aimed at those vibrations with the driving frequency outside the band gap(s). By adjusting external inductance, the equivalent circuit of the proposed structure can be forced into parallel resonance such that most of the vibration energy is converted into electrical energy for dissipation by a resistance. Thus, an external circuit under the parallel resonance state is equivalent to a strong damping to the interrelated vibrating structure, which is just the action mechanism of the active vibration reduction performance of the proposed smart structure.

  3. Model reduction and analysis of a vibrating beam microgyroscope

    KAUST Repository

    Ghommem, Mehdi; Nayfeh, Ali Hasan; Choura, Slim A.


    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:

  4. Model reduction and analysis of a vibrating beam microgyroscope

    KAUST Repository

    Ghommem, Mehdi


    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:

  5. The Vibration Sensors Optimum Mounting Analysis at Planetary Reduction Gearmotor Vibration Diagnostics


    Ļitvinovs, D


    Due to the specific mechanical peculiarities, planetary reduction gearmotors were and remain the most progressive types of reduction gearboxes for industry application. Compactness, small specific gravity and, simultaneously, possibility to pass the increased loadings – here what planetary reduction gearmotors are attractive for developers and customers. Because of planetary reduction gearmotors increased amount applying in industry, increases the requirements in their diagnostics. For this p...

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  8. Optimal placement of trailing-edge flaps for helicopter vibration reduction using response surface methods (United States)

    Viswamurthy, S. R.; Ganguli, Ranjan


    This study aims to determine optimal locations of dual trailing-edge flaps to achieve minimum hub vibration levels in a helicopter, while incurring low penalty in terms of required trailing-edge flap control power. An aeroelastic analysis based on finite elements in space and time is used in conjunction with an optimal control algorithm to determine the flap time history for vibration minimization. The reduced hub vibration levels and required flap control power (due to flap motion) are the two objectives considered in this study and the flap locations along the blade are the design variables. It is found that second order polynomial response surfaces based on the central composite design of the theory of design of experiments describe both objectives adequately. Numerical studies for a four-bladed hingeless rotor show that both objectives are more sensitive to outboard flap location compared to the inboard flap location by an order of magnitude. Optimization results show a disjoint Pareto surface between the two objectives. Two interesting design points are obtained. The first design gives 77 percent vibration reduction from baseline conditions (no flap motion) with a 7 percent increase in flap power compared to the initial design. The second design yields 70 percent reduction in hub vibration with a 27 percent reduction in flap power from the initial design.

  9. A New CMOS Posicast Pre-shaper for Vibration Reduction of CMOS Op-Amps (United States)

    Rasoulzadeh, M.; Ghaznavi-Ghoushchi, M. B.


    Posicast-based control is a widely used method in vibration reduction of lightly damped oscillatory systems especially in mechanical fields. The target systems to apply Posicast method are the systems which are excited by pulse inputs. Using the Posicast idea, the input pulse is reshaped into a new pulse, which is called Posicast pulse. Applying the generated Posicast pulse reduces the undesired oscillatory manner of under-test systems. In this paper, a fully CMOS Pulse pre-shaper circuit for realization of Posicast command is proposed. Our design is based on delay-and-add approach for the incoming pulses. The delay is done via a modified Schmitt Trigger-like circuit. The adder circuit is implemented by a simple non-binary analog adder terminated by a passive element. Our proposed design has a reasonable flexibility in configuration of time delay and amplitude of the desired pulse-like shapes. The delay is controlled via the delay unit and the pre-shaped pulse's amplitudes are controlled by an analog adder unit. The overall system has 18 MOS transistors, one small capacitor, and one resistor. To verify the effectiveness of the recommended method, it is experienced on a real CMOS Op-Amp. HSPICE simulation results, on 0.25u technology, show a significant reduction on overshoot and settling time of the under-test Op-Amp. The mentioned reduction is more than 95% in overshoot and more than 60% in settling time of the system.

  10. Reduction method for residual stress of welded joint using harmonic vibrational load

    International Nuclear Information System (INIS)

    Aoki, Shigeru; Nishimura, Tadashi; Hiroi, Tetsumaro; Hirai, Seiji


    Welding is widely used for construction of many structures. Since welding is a process using locally given heat, residual stress is generated near the bead. Tensile residual stress degrades fatigue strength. Some reduction methods of residual stress have been presented and, for example, heat treatment and shot peening are practically used. However, those methods need special tools and are time consuming. In this paper, a new method for reduction of residual stress using harmonic vibrational load during welding is proposed. The proposed method is examined experimentally for some conditions. Two thin plates are supported on the supporting device and butt-welded using an automatic CO 2 gas shielded arc welding machine. Residual stress in the direction of the bead is measured by using a paralleled beam X-ray diffractometer with scintillation counter after removing quenched scale chemically. First, the welding of rolled steel for general structure for some excitation frequencies is examined. Specimens are welded along the groove on both sides. For all frequencies, tensile residual stress near the bead is significantly reduced. Second, welding of the specimen made of high tensile strength steel is examined. In this case, tensile residual stress near the bead is also reduced. Finally, the proposed method is examined by an analytical method. An analytical model which consists of mass and preloaded springs with elasto-plastic characteristic is used. Reduction of residual stress is demonstrated using this model

  11. Investigation of a vibration-damping unit for reduction in low-frequency vibrations of electric motors (United States)

    Grigoryey, N. V.; Fedorovich, M. A.


    The vibroacoustical characteristics of different types of electric motors are discussed. It is shown that the basic source of low frequency vibrations is rotor unbalance. A flexible damping support, with an antivibrator, is used to obtain the vibroacoustical effect of reduction in the basic harmonic of the electric motor. A model of the electric motor and the damping apparatus is presented. Mathematical models are developed to show the relationships of the parameters. The basic purpose in using a calculation model id the simultaneous replacement of the exciting force created by the rotor unbalance and its inertial rigidity characteristics by a limiting kinematic disturbance.

  12. Noise and vibration reduction technology in hybrid vehicle development; Hybrid sha kaihatsu ni okeru shindo soon teigen gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioa, T.; Sugita, H. [Toyota Motor Corp., Aichi (Japan)


    Accomplishing both environmental protection and good NVH performance has become a significant task in automotive development The first-in-the-world hybrid passenger car of mass production. 'Prius', has achieved superior NV performance compared with conventional vehicles with a 1.5-liter engine along with 50% reduction of fuel consumption and CO{sub 2} emissions. low HC, CO and NO{sub x} emissions. This paper describes NV reduction technology for solving problems peculiar to the hybrid vehicle such as engine start/stop vibration, drone noise at low engine speed and motor/generator noise and vibration. It also mentions application technology of low rolling resistance tires with light weight wheels and recycled material for sound proofing. (author)

  13. Intermittent whole-body vibration attenuates a reduction in the number of the capillaries in unloaded rat skeletal muscle. (United States)

    Kaneguchi, Akinori; Ozawa, Junya; Kawamata, Seiichi; Kurose, Tomoyuki; Yamaoka, Kaoru


    Whole-body vibration has been suggested for the prevention of muscle mass loss and muscle wasting as an attractive measure for disuse atrophy. This study examined the effects of daily intermittent whole-body vibration and weight bearing during hindlimb suspension on capillary number and muscle atrophy in rat skeletal muscles. Sixty male Wistar rats were randomly divided into four groups: control (CONT), hindlimb suspension (HS), HS + weight bearing (WB), and HS + whole-body vibration (VIB) (n = 15 each). Hindlimb suspension was applied for 2 weeks in HS, HS + WB, and HS + VIB groups. During suspension, rats in HS + VIB group were placed daily on a vibrating whole-body vibration platform for 20 min. In HS + WB group, suspension was interrupted for 20 min/day, allowing weight bearing. Untreated rats were used as controls. Soleus muscle wet weights and muscle fiber cross-sectional areas (CSA) significantly decreased in HS, HS + WB, and HS + VIB groups compared with CONT group. Both muscle weights and CSA were significantly greater in HS + WB and HS + VIB groups compared with HS group. Capillary numbers (represented by capillary-to-muscle fiber ratio) were significantly smaller in all hindlimb suspension-treated groups compared with CONT group. However, a reduction in capillary number by unloading hindlimbs was partially prevented by whole-body vibration. These findings were supported by examining mRNA for angiogenic-related factors. Expression levels of a pro-angiogenic factor, vascular endothelial growth factor-A mRNA, were significantly lower in all hindlimb suspension-treated groups compared with CONT group. There were no differences among hindlimb suspension-treated groups. Expression levels of an anti-angiogenic factor, CD36 (receptor for thrombospondin-1) mRNA, were significantly higher in all hindlimb suspension-treated groups compared with CONT group. Among the hindlimb suspension-treated groups, expression of CD

  14. Reduction of interior sound fields in flexible cylinders by active vibration control (United States)

    Jones, J. D.; Fuller, C. R.


    The mechanisms of interior sound reduction through active control of a thin flexible shell's vibrational response are presently evaluated in view of an analytical model. The noise source is a single exterior acoustic monopole. The active control model is evaluated for harmonic excitation; the results obtained indicate spatially-averaged noise reductions in excess of 20 dB over the source plane, for acoustic resonant conditions inside the cavity.

  15. Significant thermal energy reduction in lactic acid production process

    International Nuclear Information System (INIS)

    Mujtaba, Iqbal M.; Edreder, Elmahboub A.; Emtir, Mansour


    Lactic acid is widely used as a raw material for the production of biodegradable polymers and in food, chemical and pharmaceutical industries. The global market for lactic acid is expected to reach 259 thousand metric tons by the year 2012. For batch production of lactic acid, the traditional process includes the following steps: (i) esterification of impure lactic acid with methanol in a batch reactor to obtain methyl lactate (ester), (ii) separation of the ester in a batch distillation, (iii) hydrolysis of the ester with water in a batch reactor to produce lactic acid and (iv) separation of lactic acid (in high purity) in a batch distillation. Batch reactive distillation combines the benefit of both batch reactor and batch distillation and enhances conversion and productivity (Taylor and Krishna, 2000 ; Mujtaba and Macchietto, 1997 ). Therefore, the first and the last two steps of the lactic acid production process can be combined together in batch reactive distillation () processes. However, distillation (batch or continuous) is an energy intensive process and consumes large amount of thermal energy (via steam). This paper highlights how significant (over 50%) reduction in thermal energy consumption can be achieved for lactic acid production process by carefully controlling the reflux ratio but without compromising the product specification. In this paper, only the simultaneous hydrolysis of methyl lactate ester and the separation of lactic acid using batch reactive distillation is considered.

  16. Resisting the therapeutic reduction: on the significance of sin. (United States)

    Delkeskamp-Hayes, Corinna


    Sin-talk, though politically incorrect, is indispensable. Placing human life under the "hermeneutic of sin" means acknowledging that one ought to aim flawlessly at God, and that one can fail in this endeavor. None of this can be appreciated within the contemporary post-Christian, mindset, which has attempted to reduce religion to morality and culture. In such a secular context, the guilt-feelings connected with the recognition of sin are considered to be harmful; the eternal benefit of a repentance is disregarded. Nevertheless, spirituality appears to have therapeutic benefits. Therefore attempts are made to re-locate within healthcare a religion shorn of its transcendent claims, so as then to harvest the benefits of a spirituality "saved from sin". This reduction of religiosity to its therapeutic function is nourished by a post-modern constructivist construal of religion. This article critically examines the dis-ingenuity marring such recasting, as well as the incoherence of related attempts to reduce transcendence to solidarity, and to re-shape the significance of religious rituals.

  17. Ride comfort enhancement in railway vehicle by the reduction of the car body structural flexural vibration (United States)

    Dumitriu, M.


    The paper approaches the issue of reduction in the vertical bending vibrations of the railway vehicle carbody and the ride comfort enhancement at high velocities, starting from the prospect of isolating the vibrations by the best possible selection of the passive suspension damping in the vehicle. To this purpose, the examination falls on the influence of the vertical suspension damping upon the vibrations regime of the vehicle at the bending resonance frequency and upon the ride comfort. The results of the numerical simulations regarding the frequency response of the carbody acceleration and the comfort index will be therefore used. A value of the secondary suspension damping can be thus identified that will provide the best ride comfort performance. Similarly, the ride comfort can be increased by raising the primary suspension damping ratio.

  18. Finite element analysis using NASTRAN applied to helicopter transmission vibration/noise reduction (United States)

    Howells, R. W.; Sciarra, J. J.


    A finite element NASTRAN model of the complete forward rotor transmission housing for the Boeing Vertol CH-47 helicopter was developed and applied to reduce transmission vibration/noise at its source. In addition to a description of the model, a technique for vibration/noise prediction and reduction is outlined. Also included are the dynamic response as predicted by NASTRAN, test data, the use of strain energy methods to optimize the housing for minimum vibration/noise, and determination of design modifications which will be manufactured and tested. The techniques presented are not restricted to helicopters but are applicable to any power transmission system. The transmission housing model developed can be used further to evaluate static and dynamic stresses, thermal distortions, deflections and load paths, fail-safety/vulnerability, and composite materials.

  19. Study on Vibration Reduction Method for a Subway Station in Soft Ground

    Directory of Open Access Journals (Sweden)

    Xian-Feng Ma


    Full Text Available With the rapid development of metro system in urban areas, vibration and its impact on adjacent structures caused by metro operation have drawn much attention of researches and worries relating to it have risen. This paper analyzed the vibration attenuation and the environment impact by a case study of a subway station in soft ground with adjacent laboratory building. A method of setting a compound separation barrier surrounding the station is checked and different materials used in the barrier have been tried and tested through numerical analysis. Key parameters of the material and the effects of vibration reduction are studied with the purpose that similar methodology and findings can be referenced in future practices.

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

    International Nuclear Information System (INIS)

    Holostencu, Adriana; Dinu, Marius


    vibrations, (solution efficiency checked using the calibrated model). In order to reduce the pump-motor assembly vibrations, the EUROTEST/ Stevenson recommendation was to install 6 viscous dampers VES- 100. The modifications were completed in Outage 2002. After dampers coupling a considerable reduction on motor vibration level was noticed. The value read in MCR decreased from 9 mm/s to 2,5 mm/s. The results were confirmed by independent local measurements perform in field by CNE- PROD, Stevenson and Bently- Nevada teams. At the same time a slight increase of the vibration on the discharge header was noticed. The vibration regime in the discharge header was analysed by Stevenson in order to asses the impact of increased vibration on the system pipes. The analysis was made in accordance with ASME OM -S/ G. The conclusion of this analysis is that the vibrations regime for the moderator system including pumps, motors and pipes induces loads below the endurance limits. The same solution was also implemented at Quinshan NPP and it will be applied at Cernavoda NPP Unit 2

  1. Significant reductions in heart and lung doses using semi lateral ...

    African Journals Online (AJOL)

    Amr Abdul Aziz

    decubitus techniques for left sided breast cancer patients: A comparative ... Peer review under responsibility of Alexandria University Faculty of Medicine. ..... Percent of reduction is calculated as new number – original number/original number ...

  2. The region of influence of significant defects and the mechanical vibrations of linear elastic solids

    International Nuclear Information System (INIS)

    Suarez Antola, R.


    The presence of cracks, voids or fields of pores, and their growth under applied forces or environmental actions, can produce a meaningful lowering in the proper frequencies of normal modes of mechanical vibration in machines and structures. A quite general expression for the square of modes proper frequency as a functional of displacement field, density field and elastic moduli fields is used as a starting point. The effect of defects on frequency are modeled as equivalent changes in density and elastic moduli fields, introducing the concept of region of influence of each defect. This region of influence is derived from the relation between the stress field of flawed components in machines or structures, and the elastic energy released from a suitable reference state, due to the presence of significant defects in the above mentioned mechanical components. An approximate analytical expression is obtained, which relates the relative variation in the square of mode s proper frequency with position, size, shape and orientation of defects in mode displacement field. Some simple mathematical models of machine and structural elements with cracks or fields of pores are considered as examples. The connections between the relative lowering in the square of mode s proper frequency and the stress intensity factor of a defect are discussed : the concept of region of influence of a defect is used as a bridge between (low frequency and low amplitude) vibration dynamics and linear elastic fracture mechanics. Some limitations of the present approach are discussed as well as the possibility of applying the region of influence of defects to the damping of normal modes of vibration

  3. Active vibration reduction of rigid rotor by kinematic excitation of bushes of journal bearings

    Directory of Open Access Journals (Sweden)

    J. Ondrouch


    Full Text Available Possibilities of active lateral vibration reduction of a symmetric, rigid rotor supported by journal bearings are given. They were obtained by computational modelling. Efficiency of the feedback P and PD controllers in the stable revolution interval was examined. The linearized rotor system model was used. The results of the theoretical analysis are assigned for a testing stand where the bearing bush motions are deactivated by piezoelectric actuators connected to the controllers.

  4. Active vibration reduction by optimally placed sensors and actuators with application to stiffened plates by beams

    International Nuclear Information System (INIS)

    Daraji, A H; Hale, J M


    This study concerns new investigation of active vibration reduction of a stiffened plate bonded with discrete sensor/actuator pairs located optimally using genetic algorithms based on a developed finite element modeling. An isotropic plate element stiffened by a number of beam elements on its edges and having a piezoelectric sensor and actuator pair bonded to its surfaces is modeled using the finite element method and Hamilton’s principle, taking into account the effects of piezoelectric mass, stiffness and electromechanical coupling. The modeling is based on the first order shear deformation theory taking into account the effects of bending, membrane and shear deformation for the plate, the stiffening beam and the piezoelectric patches. A Matlab finite element program has been built for the stiffened plate model and verified with ANSYS and also experimentally. Optimal placement of ten piezoelectric sensor/actuator pairs and optimal feedback gain for active vibration reduction are investigated for a plate stiffened by two beams arranged in the form of a cross. The genetic algorithm was set up for optimization of sensor/actuator placement and feedback gain based on the minimization of the optimal linear quadratic index as an objective function to suppress the first six modes of vibration. Comparison study is presented for active vibration reduction of a square cantilever plate stiffened by crossed beams with two sensor/actuator configurations: firstly, ten piezoelectric sensor/actuator pairs are located in optimal positions; secondly, a piezoelectric layer of single sensor/actuator pair covering the whole of the stiffened plate as a SISO system. (paper)

  5. 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


    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)


    Directory of Open Access Journals (Sweden)

    Roberd Saragih


    Full Text Available This paper is concerned with the vibration and position control of a single link flexible manipulator. Robot link manipulators are widely used in various industrial applications. It is desirable to build light weight flexible manipulators. Light flexible manipulators have a variety of applications, most significantly in space exploration,manufacturing automation, construction, mining, and hazardous operation. Timoshenko beam theory is used to derive mathematical model of a flexible manipulator. The dynamic equations of motion are obtained using the Lagrange's formulation of dynamics.The H∞ controller is designed for vibration and position control of the system. Simulations are presented and show that vibration and position control of a single flexible link can be controlled with the designed H∞ controller.


    Directory of Open Access Journals (Sweden)

    Robert GREGA


    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.

  8. Active Vibration Reduction of Titanium Alloy Fan Blades (FAN1) Using Piezoelectric Materials (United States)

    Choi, Benjamin; Kauffman, Jeffrey; Duffy, Kirsten; Provenza, Andrew; Morrison, Carlos


    The NASA Glenn Research Center is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this paper, a digital resonant control technique emulating passive shunt circuits is used to demonstrate vibration reduction of FAN1 Ti real fan blade at the several target modes. Single-mode control and multi-mode control using one piezoelectric material are demonstrated. Also a conceptual study of how to implement this digital control system into the rotating fan blade is discussed.

  9. Single-crystal-material-based induced-shear actuation for vibration reduction of helicopters with composite rotor system

    International Nuclear Information System (INIS)

    Pawar, Prashant M; Jung, Sung Nam


    In this study, an assessment is made for the helicopter vibration reduction of composite rotor blades using an active twist control concept. Special focus is given to the feasibility of implementing the benefits of the shear actuation mechanism along with elastic couplings of composite blades for achieving maximum vibration reduction. The governing equations of motion for composite rotor blades with surface bonded piezoceramic actuators are obtained using Hamilton's principle. The equations are then solved for dynamic response using finite element discretization in the spatial and time domains. A time domain unsteady aerodynamic theory with free wake model is used to obtain the airloads. A newly developed single-crystal piezoceramic material is introduced as an actuator material to exploit its superior shear actuation authority. Seven rotor blades with different elastic couplings representing stiffness properties similar to stiff-in-plane rotor blades are used to investigate the hub vibration characteristics. The rotor blades are modeled as a box beam with actuator layers bonded on the outer surface of the top and bottom of the box section. Numerical results show that a notable vibration reduction can be achieved for all the combinations of composite rotor blades. This investigation also brings out the effect of different elastic couplings on various vibration-reduction-related parameters which could be useful for the optimal design of composite helicopter blades

  10. Single-crystal-material-based induced-shear actuation for vibration reduction of helicopters with composite rotor system (United States)

    Pawar, Prashant M.; Jung, Sung Nam


    In this study, an assessment is made for the helicopter vibration reduction of composite rotor blades using an active twist control concept. Special focus is given to the feasibility of implementing the benefits of the shear actuation mechanism along with elastic couplings of composite blades for achieving maximum vibration reduction. The governing equations of motion for composite rotor blades with surface bonded piezoceramic actuators are obtained using Hamilton's principle. The equations are then solved for dynamic response using finite element discretization in the spatial and time domains. A time domain unsteady aerodynamic theory with free wake model is used to obtain the airloads. A newly developed single-crystal piezoceramic material is introduced as an actuator material to exploit its superior shear actuation authority. Seven rotor blades with different elastic couplings representing stiffness properties similar to stiff-in-plane rotor blades are used to investigate the hub vibration characteristics. The rotor blades are modeled as a box beam with actuator layers bonded on the outer surface of the top and bottom of the box section. Numerical results show that a notable vibration reduction can be achieved for all the combinations of composite rotor blades. This investigation also brings out the effect of different elastic couplings on various vibration-reduction-related parameters which could be useful for the optimal design of composite helicopter blades.

  11. Constructing a holistic approach to disaster risk reduction: the significance of focusing on vulnerability reduction. (United States)

    Palliyaguru, Roshani; Amaratunga, Dilanthi; Baldry, David


    As a result of the increase in natural disaster losses, policy-makers, practitioners, and members of the research community around the world are seeking effective and efficient means of overcoming or minimising them. Although various theoretical constructs are beneficial to understanding the disaster phenomenon and the means of minimising losses, the disaster risk management process becomes less effective if theory and practice are set apart from one another. Consequently, this paper seeks to establish a relationship between two theoretical constructs, 'disaster risk reduction (DRR)' and 'vulnerability reduction', and to develop a holistic approach to DRR with particular reference to improving its applicability in practical settings. It is based on a literature review and on an overall understanding gained through two case studies of post-disaster infrastructure reconstruction projects in Sri Lanka and three expert interviews in Sri Lanka and the United Kingdom. © 2014 The Author(s). Disasters © Overseas Development Institute, 2014.

  12. Minute Impurities Contribute Significantly to Olfactory Receptor Ligand Studies: Tales from Testing the Vibration Theory


    Paoli, M.; M?nch, D.; Haase, A.; Skoulakis, E.; Turin, L.; Galizia, C. G.


    Several studies have attempted to test the vibrational hypothesis of odorant receptor activation in behavioral and physiological studies using deuterated compounds as odorants. The results have been mixed. Here, we attempted to test how deuterated compounds activate odorant receptors using calcium imaging of the fruit fly antennal lobe. We found specific activation of one area of the antennal lobe corresponding to inputs from a specific receptor. However, upon more detailed analysis, we disco...

  13. Optimal deployment schedule of an active twist rotor for performance enhancement and vibration reduction in high-speed flights

    Directory of Open Access Journals (Sweden)

    Young H. YOU


    Full Text Available The best active twist schedules exploiting various waveform types are sought taking advantage of the global search algorithm for the reduction of hub vibration and/or power required of a rotor in high-speed conditions. The active twist schedules include two non-harmonic inputs formed based on segmented step functions as well as the simple harmonic waveform input. An advanced Particle Swarm assisted Genetic Algorithm (PSGA is employed for the optimizer. A rotorcraft Computational Structural Dynamics (CSD code CAMRAD II is used to perform the rotor aeromechanics analysis. A Computation Fluid Dynamics (CFD code is coupled with CSD for verification and some physical insights. The PSGA optimization results are verified against the parameter sweep study performed using the harmonic actuation. The optimum twist schedules according to the performance and/or vibration reduction strategy are obtained and their optimization gains are compared between the actuation cases. A two-phase non-harmonic actuation schedule demonstrates the best outcome in decreasing the power required while a four-phase non-harmonic schedule results in the best vibration reduction as well as the simultaneous reductions in the power required and vibration. The mechanism of reduction to the performance gains is identified illustrating the section airloads, angle-of-attack distribution, and elastic twist deformation predicted by the present approaches.

  14. Minute Impurities Contribute Significantly to Olfactory Receptor Ligand Studies: Tales from Testing the Vibration Theory. (United States)

    Paoli, M; Münch, D; Haase, A; Skoulakis, E; Turin, L; Galizia, C G


    Several studies have attempted to test the vibrational hypothesis of odorant receptor activation in behavioral and physiological studies using deuterated compounds as odorants. The results have been mixed. Here, we attempted to test how deuterated compounds activate odorant receptors using calcium imaging of the fruit fly antennal lobe. We found specific activation of one area of the antennal lobe corresponding to inputs from a specific receptor. However, upon more detailed analysis, we discovered that an impurity of 0.0006% ethyl acetate in a chemical sample of benzaldehyde-d 5 was entirely responsible for a sizable odorant-evoked response in Drosophila melanogaster olfactory receptor cells expressing dOr42b. Without gas chromatographic purification within the experimental setup, this impurity would have created a difference in the responses of deuterated and nondeuterated benzaldehyde, suggesting that dOr42b be a vibration sensitive receptor, which we show here not to be the case. Our results point to a broad problem in the literature on use of non-GC-pure compounds to test receptor selectivity, and we suggest how the limitations can be overcome in future studies.

  15. Significant reduction of thermal conductivity in Si/Ge core-shell nanowires. (United States)

    Hu, Ming; Giapis, Konstantinos P; Goicochea, Javier V; Zhang, Xiaoliang; Poulikakos, Dimos


    We report on the effect of germanium (Ge) coatings on the thermal transport properties of silicon (Si) nanowires using nonequilibrium molecular dynamics simulations. Our results show that a simple deposition of a Ge shell of only 1 to 2 unit cells in thickness on a single crystalline Si nanowire can lead to a dramatic 75% decrease in thermal conductivity at room temperature compared to an uncoated Si nanowire. By analyzing the vibrational density states of phonons and the participation ratio of each specific mode, we demonstrate that the reduction in the thermal conductivity of Si/Ge core-shell nanowire stems from the depression and localization of long-wavelength phonon modes at the Si/Ge interface and of high frequency nonpropagating diffusive modes.

  16. A pilot weight reduction program over one year significantly reduced DNA strand breaks in obese subjects

    Directory of Open Access Journals (Sweden)

    Karl-Heinz Wagner


    Conclusion: A sustainable lifestyle change under supervision including physical activity and diet quality over a period of one year was not only responsible to reduce body weight and BMI but also led to significant reduction in all parameters of the comet assay. These results underline the importance of body weight reduction and highlight the positive changes in DNA stability.

  17. Reduction of vibration forces transmitted from a radiator cooling fan to a vehicle body (United States)

    Lim, Jonghyuk; Sim, Woojeong; Yun, Seen; Lee, Dongkon; Chung, Jintai


    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.

  18. Leukocyte-reduction filters and radiation do not cause significant changes in platelet function

    International Nuclear Information System (INIS)

    Nagura, Yutaka; Tsuno, Hirokazu; Shibata, Yoichi; Takahashi, Koki


    In the present study, we investigated the effects of radiation and leukocyte-reduction filters on platelet function. Platelet aggregation in response to collagen and ADP were measured prior to and after irradiation and filtration, as were the platelet recovery rate and complement factor C3. Four types of leukocyte-reduction filter were used, namely positively-, negatively-, and non-charged filters (all of polyester composition), as well as a polyurethane filter. Radiation itself did not significantly affect either the platelet recovery rate, platelet function, or C3 value. On the other hand, filtration through polyester leukocyte-reduction filters resulted in a significant reduction in the platelet recovery rate, an effect not observed with the polyurethane filter. However, none of the filters caused significant changes in platelet function or in C3 value. We concluded that radiation and filtration do not cause significant changes in platelet function, but polyurethane filters are superior to polyester filters in relation to platelet recovery. (author)

  19. GHG emission scenarios in Asia and the world: The key technologies for significant reduction

    International Nuclear Information System (INIS)

    Akashi, Osamu; Hijioka, Yasuaki; Masui, Toshihiko; Hanaoka, Tatsuya; Kainuma, Mikiko


    In this paper, we explore GHG emission scenarios up to 2050 in Asia and the world as part of the Asian Modeling Exercise and assess technology options for meeting a 2.6 W/m 2 radiative forcing target using AIM/Enduse[Global] and AIM/Impact[Policy]. Global GHG emissions in 2050 are required to be reduced by 72% relative to a reference scenario, which corresponds to a 57% reduction from the 2005 level, in order to meet the above target. Energy intensity improvement contributes a lot to curbing CO 2 emission in the short-term. Meanwhile, carbon intensity reduction and CO 2 capture play a large role for further emission reduction in the mid to long-term. The top five key technologies in terms of reduction amount are CCS, solar power generation, wind power generation, biomass power generation and biofuel, which, in total, account for about 60% of global GHG emissions reduction in 2050. We implement additional model runs, each of which enforced limited availability of one of the key technology. The result shows that the 2.6 W/m 2 target up to 2050 is achievable even if availability of any one of the key technologies is limited to half the level achieved in the default simulation. However, if the use of CCS or biomass is limited, the cumulative GHG abatement cost until 2050 increases considerably. Therefore CCS and biomass have a vital role in curbing costs to achieve significant emission reductions. - Highlights: ► We explore GHG emission scenarios up to 2050 in Asia and the world. ► Significant GHG emission reduction is required to limit radiative forcing at low level. ► We assess technology options for achieving significant GHG emission reduction. ► CCS, solar power, wind power, and biomass are the key technologies for reduction. ► Especially, CCS and biomass play a vital role in curbing costs to achieve significant emission reductions.

  20. Vibration reduction methods and techniques for rotorcraft utilizing on-blade active control, Phase I (United States)

    National Aeronautics and Space Administration — Rotor blades adapted for vibration control have the added benefit of extended blade and rotor life, as well as improved passenger comfort. Approaches that have been...

  1. Study on design method and vibration reduction characteristic of floating raft with periodic structure (United States)

    Fang, Yuanyuan; Zuo, Yanyan; Xia, Zhaowang


    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.

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

    International Nuclear Information System (INIS)

    Ashhab, M S


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

  3. Novel active vibration absorber with magnetorheological fluid

    Energy Technology Data Exchange (ETDEWEB)

    Gerlach, T; Ehrlich, J; Boese, H [Fraunhofer-Institut fuer Silicatforschung ISC, Neunerplatz 2, D-97082 Wuerzburg (Germany)], E-mail:


    Disturbing vibrations diminish the performance of technical high precision devices significantly. In search of a suitable solution for reducing these vibrations, a novel concept of active vibration reduction was developed which exploits the special properties of magnetorheological fluids. In order to evaluate the concept of such an active vibration absorber (AVA) a demonstrator was designed and manufactured. This demonstrator generates a force which counteracts the motion of the vibrating body. Since the counterforce is generated by a centrifugal exciter, the AVA provides the capability to compensate vibrations even in two dimensions. To control the strength of the force transmitted to the vibrating body, the exciter is based on a tunable MR coupling. The AVA was integrated in an appropriate testing device to investigate its performance. The recorded results show a significant reduction of the vibration amplitudes by an order of magnitude.

  4. Vibration Reduction of Wind Turbines Using Tuned Liquid Column Damper Using Stochastic Analysis

    International Nuclear Information System (INIS)

    Alkmim, M H; De Morais, M V G; Fabro, A T


    Passive energy dissipation systems encompass a range of materials and devices for enhancing damping. They can be used both for natural hazard mitigation and for rehabilitation of aging or deficient structures. Among the current passive energy dissipation systems, tuned liquid column damper (TLCD), a class of passive control that utilizes liquid in a “U” shape reservoir to control structural vibration of the primary system, has been widely researched in a variety of applications. This paper focus in TLCD application for wind turbines presenting the mathematical model as well as the methods used to overcome the nonlinearity embedded in the system. Optimization methods are used to determine optimum parameters of the system. Additionally, a comparative analysis is done considering the equivalent linearized system and the nonlinear system under random excitation with the goal of compare the nonlinear model with the linear equivalent and investigated the effectiveness of the TLCD. The results are shown using two types of random excitation, a white noise and a first order filters spectrum, the latter presents more satisfactory results since the excitation spectrum is physically more realistic than white noise spectrum model. The results indicate that TLCDs at optimal tuning can significantly dissipate energy of the primary structure between 3 to 11%. (paper)

  5. Vibration reduction and power generation with piezoceramic sheets mounted to a flexible shaft

    NARCIS (Netherlands)

    Sloetjes, P.J.; de Boer, Andries


    A flexible shaft with surface-mounted piezoceramic sheets and strain sensors is considered which suffers from resonance and self-excited vibration. Frequency domain models, time domain simulations, and control experiments are used to analyze active modal damping and active modal balancing methods.

  6. Time to significant pain reduction following DETP application vs placebo for acute soft tissue injuries. (United States)

    Yanchick, J; Magelli, M; Bodie, J; Sjogren, J; Rovati, S


    Nonsteroidal anti-inflammatory drugs (NSAIDs) provide fast and effective acute pain relief, but systemic administration has increased risk for some adverse reactions. The diclofenac epolamine 1.3% topical patch (DETP) is a topical NSAID with demonstrated safety and efficacy in treatment of acute pain from minor soft tissue injuries. Significant pain reduction has been observed in clinical trials within several hours following DETP application, suggesting rapid pain relief; however, this has not been extensively studied for topical NSAIDs in general. This retrospective post-hoc analysis examined time to onset of significant pain reduction after DETP application compared to a placebo patch for patients with mild-to-moderate acute ankle sprain, evaluating the primary efficacy endpoint from two nearly identical studies. Data from two double-blind, randomized, parallel-group, placebo-controlled studies (N = 274) of safety and efficacy of the DETP applied once daily for 7 days for acute ankle sprain were evaluated post-hoc using statistical modeling to estimate time to onset of significant pain reduction following DETP application. Pain on active movement on a 100 mm Visual Analog Scale (VAS) recorded in patient diaries; physician- and patient-assessed tolerability; and adverse events. DETP treatment resulted in significant pain reduction within approximately 3 hours compared to placebo. Within-treatment post-hoc analysis based on a statistical model suggested significant pain reduction occurred as early as 1.27 hours for the DETP group. The study may have been limited by the retrospective nature of the analyses. In both studies, the DETP was well tolerated with few adverse events, limited primarily to application site skin reactions. The DETP is an effective treatment for acute minor soft tissue injury, providing pain relief as rapidly as 1.27 hours post-treatment. Statistical modeling may be useful in estimating time to onset of pain relief for comparison of topical

  7. An Overview of Recent Automotive Applications of Active Vibration Control

    National Research Council Canada - National Science Library

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


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

  8. The significant reduction of precipitation in Southern China during the Chinese Spring Festival (United States)

    Zhang, J.; Gong, D.


    Long-term observational data from 2001 to 2012 over 339 stations were used to analyze the precipitation in southern China during the Chinese Spring Festival (CSF). It reveals both the precipitation frequency and precipitation intensity have a significant reduction around CSF holiday. From the second day to the sixth day after the Lunar New Year's Day, the daily mean precipitation frequency anomaly is -9%. At the same time, more than 90% stations in the study area have negative anomalies. The precipitation intensity has a continuous reduction from day 2 to day 4, which is up to 2mm in day 3. Other relevant variables, such as relative humidity and sunshine duration, have corresponding results to the precipitation's reduction during CSF. Atmospheric water vapor field's change leads to the reduction phenomenon. We analyzed the circulation configuration using the ERA-interim reanalysis data. It shows the anomalous north wind decrease the vapor and further affects the precipitation during the CSF period. The pollutants' concentration decreased around CSF, which may influence the meteorological field and lead to the anomalous north wind. Based on the S2S (sub-seasonal to seasonal prediction project) data, we calculated the circulation forecast difference to CSF period between clean days and polluted days. The result proves the north wind's existence and suggests that the aerosol decrease because of human activity may be partly responsible for the precipitation reduction during CSF.

  9. Comparison of dimensionality reduction techniques for the fault diagnosis of mono block centrifugal pump using vibration signals

    Directory of Open Access Journals (Sweden)

    N.R. Sakthivel


    Full Text Available Bearing fault, Impeller fault, seal fault and cavitation are the main causes of breakdown in a mono block centrifugal pump and hence, the detection and diagnosis of these mechanical faults in a mono block centrifugal pump is very crucial for its reliable operation. Based on a continuous acquisition of signals with a data acquisition system, it is possible to classify the faults. This is achieved by the extraction of features from the measured data and employing data mining approaches to explore the structural information hidden in the signals acquired. In the present study, statistical features derived from the vibration data are used as the features. In order to increase the robustness of the classifier and to reduce the data processing load, dimensionality reduction is necessary. In this paper dimensionality reduction is performed using traditional dimensionality reduction techniques and nonlinear dimensionality reduction techniques. The effectiveness of each dimensionality reduction technique is also verified using visual analysis. The reduced feature set is then classified using a decision tree. The results obtained are compared with those generated by classifiers such as Naïve Bayes, Bayes Net and kNN. The effort is to bring out the better dimensionality reduction technique–classifier combination.

  10. Integrated vibration-based maintenance: an approach for continuous reduction in LCC. A case study

    Energy Technology Data Exchange (ETDEWEB)

    Najjar, B. [ER Konsult Utveckling AB, Vaexjoe (Sweden)


    The biggest thread in achieving and maintaining high equipment effectiveness can be stated as: whether the improved manufacturing processes capable of producing quality products at a competitive cost. The effect of a new vibration-based maintenance concept, called Total Quality Maintenance (TQMain), is introduced. It aims to make intensive use of the real-time data acquisition and analysis to detect causes behind product quality deviation and failures in machinery, and following defect development at an early stage to increase machine mean effective life and improve company`s economics. The effect of TQMain on LCC of machinery and company`s economics is discussed. A case study to reveal savings in maintenance cost when a vibration-based policy involved, is presented. Using TQMain, company`s economics can be improved effectively through continuous improvement of the technical and economic effectiveness of production processes. (orig.) 14 refs.

  11. Integrated vibration-based maintenance: an approach for continuous reduction in LCC. A case study

    Energy Technology Data Exchange (ETDEWEB)

    Najjar, B [ER Konsult Utveckling AB, Vaexjoe (Sweden)


    The biggest thread in achieving and maintaining high equipment effectiveness can be stated as: whether the improved manufacturing processes capable of producing quality products at a competitive cost. The effect of a new vibration-based maintenance concept, called Total Quality Maintenance (TQMain), is introduced. It aims to make intensive use of the real-time data acquisition and analysis to detect causes behind product quality deviation and failures in machinery, and following defect development at an early stage to increase machine mean effective life and improve company`s economics. The effect of TQMain on LCC of machinery and company`s economics is discussed. A case study to reveal savings in maintenance cost when a vibration-based policy involved, is presented. Using TQMain, company`s economics can be improved effectively through continuous improvement of the technical and economic effectiveness of production processes. (orig.) 14 refs.

  12. Intraoperative Sensorcaine significantly improves postoperative pain management in outpatient reduction mammaplasty. (United States)

    Culliford, Alfred T; Spector, Jason A; Flores, Roberto L; Louie, Otway; Choi, Mihye; Karp, Nolan S


    Breast reduction is one of the most frequently performed plastic surgical procedures in the United States; more than 160,500 patients underwent the procedure in 2005. Many outpatient reduction mammaplasty patients report the greatest postoperative discomfort in the first 48 hours. The authors' investigated the effect of intraoperative topical application of the long-acting local anesthetic agent bupivacaine (Sensorcaine or Marcaine) on postoperative pain, time to postanesthesia care unit discharge, and postoperative use of narcotic medication. In a prospective, randomized, single-blind trial, intraoperative use of Sensorcaine versus placebo (normal saline) was compared. Postoperative pain was quantified using the visual analogue scale, and time to discharge from the postanesthesia care unit was recorded. Patients documented their outpatient pain medication usage. Of the 37 patients enrolled in the study, 20 were treated with intraoperative topical Sensorcaine and 17 received placebo. Patients treated with Sensorcaine were discharged home significantly faster (2.9 hours versus 3.8 hours, p = 0.002). The control arm consistently had higher pain scores in the postanesthesia care unit (although not statistically significant) than the Sensorcaine group using the visual analogue scale system. Furthermore, patients receiving Sensorcaine required significantly less narcotic medication while recovering at home (mean, 3.5 tablets of Vicodin) than the control group (mean, 6.4 tablets; p = 0.001). There were no complications resulting from Sensorcaine usage. This prospective, randomized, single-blind study demonstrates that a single dose of intraoperative Sensorcaine provides a safe, inexpensive, and efficacious way to significantly shorten the length of postanesthesia care unit stay and significantly decrease postoperative opioid analgesic use in patients undergoing ambulatory reduction mammaplasty.

  13. Reduction of Ground Vibration by Means of Barriers or Soil Improvement along a Railway Track

    DEFF Research Database (Denmark)

    Andersen, Lars; Nielsen, Søren R.K.


    Trains running in built-up areas are a source to ground-borne noise. A careful design of the track may be one way of minimizing the vibrations in the surroundings. For example, open or infilled trenches may be constructed along the track, or the soil underneath the track may be improved...... the vehicle. The computations are carried out in the frequency domain for various combinations of the vehicle speed and the excitation frequency. The analyses indicate that open trenches are more efficient than infilled trenches or soil stiffening–even at low frequencies. However, the direction of the load...

  14. Serious fighting-related injuries produce a significant reduction in intelligence. (United States)

    Schwartz, Joseph A; Beaver, Kevin M


    Fighting-related injuries are common among adolescents within the United States, but how such injuries relate to subsequent cognitive functioning remains unclear. In particular, the long-term effect of fighting-related injuries suffered during important developmental periods, such as adolescence, on subsequent cognitive functioning has been overlooked by previous studies. The purpose of this study is to examine the association between sustaining serious fighting-related injuries and changes in verbal intelligence (IQ) over a 5- to 6-year time period. Longitudinal multivariate statistical models were used to analyze data from the National Longitudinal Study of Adolescent Health collected between 1994 and 2002 and analyzed in 2013. Even a single fighting-related injury resulted in a significant reduction in IQ over time even after controlling for age, race, sex, and changes in socioeconomic status (SES) over the study period. Additionally, females experienced a significantly greater reduction in IQ from each fighting-related injury than males. Fighting-related injuries have a significant impact on subsequent cognitive functioning and intelligence. The implications for future policies and research are discussed in more detail. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  15. A method of noise reduction in heterodyne interferometric vibration metrology by combining auto-correlation analysis and spectral filtering (United States)

    Hao, Hongliang; Xiao, Wen; Chen, Zonghui; Ma, Lan; Pan, Feng


    Heterodyne interferometric vibration metrology is a useful technique for dynamic displacement and velocity measurement as it can provide a synchronous full-field output signal. With the advent of cost effective, high-speed real-time signal processing systems and software, processing of the complex signals encountered in interferometry has become more feasible. However, due to the coherent nature of the laser sources, the sequence of heterodyne interferogram are corrupted by a mixture of coherent speckle and incoherent additive noise, which can severely degrade the accuracy of the demodulated signal and the optical display. In this paper, a new heterodyne interferometric demodulation method by combining auto-correlation analysis and spectral filtering is described leading to an expression for the dynamic displacement and velocity of the object under test that is significantly more accurate in both the amplitude and frequency of the vibrating waveform. We present a mathematical model of the signals obtained from interferograms that contain both vibration information of the measured objects and the noise. A simulation of the signal demodulation process is presented and used to investigate the noise from the system and external factors. The experimental results show excellent agreement with measurements from a commercial Laser Doppler Velocimetry (LDV).

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

    Pohl, Martin; Rose, Michael


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

  17. Optimal placement of water-lubricated rubber bearings for vibration reduction of flexible multistage rotor systems (United States)

    Liu, Shibing; Yang, Bingen


    Flexible multistage rotor systems with water-lubricated rubber bearings (WLRBs) have a variety of engineering applications. Filling a technical gap in the literature, this effort proposes a method of optimal bearing placement that minimizes the vibration amplitude of a WLRB-supported flexible rotor system with a minimum number of bearings. In the development, a new model of WLRBs and a distributed transfer function formulation are used to define a mixed continuous-and-discrete optimization problem. To deal with the case of uncertain number of WLRBs in rotor design, a virtual bearing method is devised. Solution of the optimization problem by a real-coded genetic algorithm yields the locations and lengths of water-lubricated rubber bearings, by which the prescribed operational requirements for the rotor system are satisfied. The proposed method is applicable either to preliminary design of a new rotor system with the number of bearings unforeknown or to redesign of an existing rotor system with a given number of bearings. Numerical examples show that the proposed optimal bearing placement is efficient, accurate and versatile in different design cases.

  18. Research on noise and vibration reduction at DB to improve the environmental friendliness of railway traffic (United States)

    Schulte-Werning, B.; Beier, M.; Degen, K. G.; Stiebel, D.


    One of the most prominent keywords relating to the environmental friendliness of railway traffic is noise reduction. Thus, the research and development programme "Low Noise Railway" of Deutsche Bahn (DB) is under way to treat the noise of the vehicles and infrastructure. The noise reduction of the trains and the rail/wheel system are being tackled within several projects. The direct noise experienced by railway-lineside residents due to train movements on the track can be reduced by minimising the sound radiation directly at the source. This is the first-choice solution, as it proves to be the most effective countermeasure regarding a cost-benefit relation. The limit values for the noise emission as specified in the technical specification for interoperability are an essential criterion to be confirmed during the procurement process of railway vehicles. A recently developed acoustical quality management scheme establishes systematic noise management to complete the vehicle procurement process in the phases of concept, design, construction and manufacturing. In freight traffic quiet railway wheels for block brake operation will play an important role in the future to meet the goal of a low-noise railway system. A first attempt to realise successfully the low-noise potential of such optimised wheels was performed, even if with mixed results. To show ways of reducing the noise of the cooling ventilation in locomotives, DB is a partner in a development project led by Siemens. A notable 8 dB(A) noise reduction was measured. Concerning bridge noise, a project was started based on an effective and cost-efficient combination of experiments and simulations in order to develop specifications for the construction of generic low-noise bridges.

  19. Numerical Feynman integrals with physically inspired interpolation: Faster convergence and significant reduction of computational cost

    Directory of Open Access Journals (Sweden)

    Nikesh S. Dattani


    Full Text Available One of the most successful methods for calculating reduced density operator dynamics in open quantum systems, that can give numerically exact results, uses Feynman integrals. However, when simulating the dynamics for a given amount of time, the number of time steps that can realistically be used with this method is always limited, therefore one often obtains an approximation of the reduced density operator at a sparse grid of points in time. Instead of relying only on ad hoc interpolation methods (such as splines to estimate the system density operator in between these points, I propose a method that uses physical information to assist with this interpolation. This method is tested on a physically significant system, on which its use allows important qualitative features of the density operator dynamics to be captured with as little as two time steps in the Feynman integral. This method allows for an enormous reduction in the amount of memory and CPU time required for approximating density operator dynamics within a desired accuracy. Since this method does not change the way the Feynman integral itself is calculated, the value of the density operator approximation at the points in time used to discretize the Feynamn integral will be the same whether or not this method is used, but its approximation in between these points in time is considerably improved by this method. A list of ways in which this proposed method can be further improved is presented in the last section of the article.

  20. Assembling of carbon nanotubes film responding to significant reduction wear and friction on steel surface (United States)

    Zhang, Bin; Xue, Yong; Qiang, Li; Gao, Kaixong; Liu, Qiao; Yang, Baoping; Liang, Aiming; Zhang, Junyan


    Friction properties of carbon nanotubes have been widely studied and reported, however, the friction properties of carbon nanotubes related on state of itself. It is showing superlubricity under nanoscale, but indicates high shear adhesion as aligned carbon nanotube film. However, friction properties under high load (which is commonly in industry) of carbon nanotube films are seldom reported. In this paper, carbon nanotube films, via mechanical rubbing method, were obtained and its tribology properties were investigated at high load of 5 to 15 N. Though different couple pairs were employed, the friction coefficients of carbon nanotube films are nearly the same. Compared with bare stainless steel, friction coefficients and wear rates under carbon nanotube films lubrication reduced to, at least, 1/5 and 1/(4.3-14.5), respectively. Friction test as well as structure study were carried out to reveal the mechanism of the significant reduction wear and friction on steel surface. One can conclude that sliding and densifying of carbon nanotubes at sliding interface contribute to the sufficient decrease of friction coefficients and wear rates.

  1. Significant enhancement of magnetoresistance with the reduction of particle size in nanometer scale (United States)

    Das, Kalipada; Dasgupta, P.; Poddar, A.; Das, I.


    The Physics of materials with large magnetoresistance (MR), defined as the percentage change of electrical resistance with the application of external magnetic field, has been an active field of research for quite some times. In addition to the fundamental interest, large MR has widespread application that includes the field of magnetic field sensor technology. New materials with large MR is interesting. However it is more appealing to vast scientific community if a method describe to achieve many fold enhancement of MR of already known materials. Our study on several manganite samples [La1−xCaxMnO3 (x = 0.52, 0.54, 0.55)] illustrates the method of significant enhancement of MR with the reduction of the particle size in nanometer scale. Our experimentally observed results are explained by considering model consisted of a charge ordered antiferromagnetic core and a shell having short range ferromagnetic correlation between the uncompensated surface spins in nanoscale regime. The ferromagnetic fractions obtained theoretically in the nanoparticles has been shown to be in the good agreement with the experimental results. The method of several orders of magnitude improvement of the magnetoresistive property will have enormous potential for magnetic field sensor technology. PMID:26837285

  2. The significance of duration and amount of sodium reduction intervention in normotensive and hypertensive individuals

    DEFF Research Database (Denmark)

    Graudal, Niels; Hubeck-Graudal, Thorbjørn; Jürgens, Gesche


    The purpose of this meta-analysis was to establish the time for achievement of maximal blood pressure (BP) efficacy of a sodium reduction (SR) intervention and the relation between the amount of SR and the BP response in individuals with hypertension and normal BP. Relevant studies were retrieved.......12, P policy of sodium reduction....

  3. Equal vibrotactile sense thresholds of the fingers and its diagnostic significance for hand-arm vibration syndrome. (United States)

    Cheng, H; Zhang, X C; Duan, L; Ma, Y; Wang, J X


    The vibrotactile sense thresholds (VSTs) of the middle fingers of 60 healthy persons and 97 patients with Hand-Arm Vibration Syndrome (HAVS) or subclinical HAVS were measured quantitatively. Intermittent vibratory irritations were adopted, with vibration stimulus frequencies at 8, 16, 31.5, 63, 125, 250, and 500 Hz. The equal VST contours of the fingers were mapped. Results showed that the VSTs of the normal group were not correlated with sex or handedness. From 8 Hz to 250 Hz the equal VST contours of the normal group were relatively flat; at more than 250 Hz the contours began an abrupt ascent. The VST values had a logarithmic rising tendency with the increasing age of subjects. In the equal VST contours the frequency of the most sensitive threshold value was 125 Hz in the normal group and 8 Hz in the HAVS group. The patients' VST values were higher than that of the healthy persons. The vibrotactilegram showed that the VST values of the patient groups first shifted at high frequencies and VST loss displayed a "V"-type hollow at 125 Hz and 250 Hz. The quantitative test method of VST was a valuable auxiliary detection method for HAVS. The "V"-type hollow of VST was an early clinical manifestation of HAVS.

  4. Fuzzy crane control with sensorless payload deflection feedback for vibration reduction (United States)

    Smoczek, Jaroslaw


    Different types of cranes are widely used for shifting cargoes in building sites, shipping yards, container terminals and many manufacturing segments where the problem of fast and precise transferring a payload suspended on the ropes with oscillations reduction is frequently important to enhance the productivity, efficiency and safety. The paper presents the fuzzy logic-based robust feedback anti-sway control system which can be applicable either with or without a sensor of sway angle of a payload. The discrete-time control approach is based on the fuzzy interpolation of the controllers and crane dynamic model's parameters with respect to the varying rope length and mass of a payload. The iterative procedure combining a pole placement method and interval analysis of closed-loop characteristic polynomial coefficients is proposed to design the robust control scheme. The sensorless anti-sway control application developed with using PAC system with RX3i controller was verified on the laboratory scaled overhead crane.

  5. Multisource radiofrequency for fractional skin resurfacing-significant reduction of wrinkles. (United States)

    Dahan, Serge; Rousseaux, Isabelle; Cartier, Hugues


    Skin roughness, color change, wrinkles and skin laxity are the main characteristics of aging skin. Dermatologists and plastic surgeons look for a treatment that will provide both epidermal resurfacing for the improvement of skin roughness and deep volumetric heating that will trigger collagen remodeling in the dermis to reduce wrinkles and skin laxity. These goals should be achieved with minimal pain and downtime. The study included 10 subjects (Fitzpatrick's skin type 2-3) with Fitzpatrick wrinkle and elastosis scale of 5-8 (average 7.3). Treatment was done with the Fractional skin resurfacing handpiece of the EndyMed PRO multisource radiofrequency system (EndyMed Ltd, Cesarea, Israel). Treatment was repeated each month up to a total of three treatment sessions. Patients photographs were graded according to accepted scales by a board certified dermatologists. Patients' pain and satisfaction were scored using dedicated questionnaires. Doctors' satisfaction was also evaluated. Post treatment skin erythema was noted in all treated patients, lasting up to 10 hours. Fifty six percent of patients reported no pain after treatment, and the rest (44%) reported minimal pain. All patients showed significant reduction in the Fitzpatrick wrinkle score. Average Fitzpatrick wrinkle score was 7.3 at baseline, 4.9 at 1 month after the first treatment, 4.2 at 1 month after the second treatment, and 4.1 at 1 month after the third treatment. The score was similar at 3 months after the third treatment with a score of 4.1. When asked at the end of three treatment sessions, all patients answered they will recommend the treatment to their friends (66% "definitely yes" and 33% "yes"). When asked the same question 3 months after the end of treatment, all patients (100%) answered "definitely yes".

  6. Evaluation of protective gloves and working techniques for reducing hand-arm vibration exposure in the workplace. (United States)

    Milosevic, Matija; McConville, Kristiina M Valter


    Operation of handheld power tools results in exposure to hand-arm vibrations, which over time lead to numerous health complications. The objective of this study was to evaluate protective equipment and working techniques for the reduction of vibration exposure. Vibration transmissions were recorded during different work techniques: with one- and two-handed grip, while wearing protective gloves (standard, air and anti-vibration gloves) and while holding a foam-covered tool handle. The effect was examined by analyzing the reduction of transmitted vibrations at the wrist. The vibration transmission was recorded with a portable device using a triaxial accelerometer. The results suggest large and significant reductions of vibration with appropriate safety equipment. Reductions of 85.6% were achieved when anti-vibration gloves were used. Our results indicated that transmitted vibrations were affected by several factors and could be measured and significantly reduced.

  7. Reduction of low frequency vibration of truck driver and seating system through system parameter identification, sensitivity analysis and active control (United States)

    Wang, Xu; Bi, Fengrong; Du, Haiping


    This paper aims to develop an 5-degree-of-freedom driver and seating system model for optimal vibration control. A new method for identification of the driver seating system parameters from experimental vibration measurement has been developed. The parameter sensitivity analysis has been conducted considering the random excitation frequency and system parameter uncertainty. The most and least sensitive system parameters for the transmissibility ratio have been identified. The optimised PID controllers have been developed to reduce the driver's body vibration.

  8. Significant role of organic sulfur in supporting sedimentary sulfate reduction in low-sulfate environments (United States)

    Fakhraee, Mojtaba; Li, Jiying; Katsev, Sergei


    Dissimilatory sulfate reduction (DSR) is a major carbon mineralization pathway in aquatic sediments, soils, and groundwater, which regulates the production of hydrogen sulfide and the mobilization rates of biologically important elements such as phosphorus and mercury. It has been widely assumed that water-column sulfate is the main sulfur source to fuel this reaction in sediments. While this assumption may be justified in high-sulfate environments such as modern seawater, we argue that in low-sulfate environments mineralization of organic sulfur compounds can be an important source of sulfate. Using a reaction-transport model, we investigate the production of sulfate from sulfur-containing organic matter for a range of environments. The results show that in low sulfate environments (50%) of sulfate reduction. In well-oxygenated systems, porewater sulfate profiles often exhibit sub-interface peaks so that sulfate fluxes are directed out of the sediment. Our measurements in Lake Superior, the world's largest lake, corroborate this conclusion: offshore sediments act as sources rather than sinks of sulfate for the water column, and sediment DSR is supported entirely by the in-sediment production of sulfate. Sulfate reduction rates are correlated to the depth of oxygen penetration and strongly regulated by the supply of reactive organic matter; rate co-regulation by sulfate availability becomes appreciable below 500 μM level. The results indicate the need to consider the mineralization of organic sulfur in the biogeochemical cycling in low-sulfate environments, including several of the world's largest freshwater bodies, deep subsurface, and possibly the sulfate-poor oceans of the Early Earth.

  9. A Combined Probe-Molecule, Mössbauer, Nuclear Resonance Vibrational Spectroscopy, and Density Functional Theory Approach for Evaluation of Potential Iron Active Sites in an Oxygen Reduction Reaction Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kneebone, Jared L. [Univ. of Rochester, Rochester, NY (United States); Daifuku, Stephanie L. [Univ. of Rochester, Rochester, NY (United States); Kehl, Jeffrey A. [Univ. of Rochester, Rochester, NY (United States); Wu, Gang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chung, Hoon T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hu, Michael Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Alp, E. Ercan [Argonne National Lab. (ANL), Argonne, IL (United States); More, Karren L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zelenay, Piotr [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Holby, Edward F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Neidig, Michael L. [Univ. of Rochester, Rochester, NY (United States)


    While non-precious metal M-N-C (M = Fe or Co) catalysts have been developed that are effective for the oxygen reduction reaction in polymer electrolyte fuel cells, no consensus has yet been reached regarding the nature of the M sites in these heterogeneous catalysts that are responsible for reaction with dioxygen (O2). While multiple studies have developed correlations between Fe distributions in as-prepared catalysts and ORR activity, the direct identification of sites reactive towards O2 or O2-analog molecules remains a significant challenge. In the present study, we demonstrate a new approach to identifying and characterizing potential Fe active sites in complex ORR catalysts that combines an effective probe molecule (NO(g)) Mössbauer spectroscopy and nuclear resonance vibrational spectroscopy (NRVS) with density functional theory (DFT) calculations. Mössbauer spectroscopic studies demonstrate that NO(g) treatment of electrochemically reduced PANI-57Fe-C leads to selective reaction with only a sub-set of the Fe species present. Nuclear resonance vibrational spectroscopic studies identified new Fe-ligand vibrations associated with the site reactive towards NO(g). DFT calculations of vibrational properties of a small selection of previously proposed active site structures suggest that graphene zig-zag edge hosted Fe-N structures may be responsible for the observed vibrational behavior with NO(g) probe molecules. Moreover, such sites are likely also reactive to O2, possibly serving as the ORR active sites in the synthesized materials.

  10. Nitrite addition to acidified sludge significantly improves digestibility, toxic metal removal, dewaterability and pathogen reduction (United States)

    Du, Fangzhou; Keller, Jürg; Yuan, Zhiguo; Batstone, Damien J.; Freguia, Stefano; Pikaar, Ilje


    Sludge management is a major issue for water utilities globally. Poor digestibility and dewaterability are the main factors determining the cost for sludge management, whereas pathogen and toxic metal concentrations limit beneficial reuse. In this study, the effects of low level nitrite addition to acidified sludge to simultaneously enhance digestibility, toxic metal removal, dewaterability and pathogen reduction were investigated. Waste activated sludge (WAS) from a full-scale waste water treatment plant was treated at pH 2 with 10 mg NO2--N/L for 5 h. Biochemical methane potential tests showed an increase in the methane production of 28%, corresponding to an improvement from 247 ± 8 L CH4/kg VS to 317 ± 1 L CH4/kg VS. The enhanced removal of toxic metals further increased the methane production by another 18% to 360 ± 6 L CH4/kg VS (a total increase of 46%). The solids content of dewatered sludge increased from 14.6 ± 1.4% in the control to 18.2 ± 0.8%. A 4-log reduction for both total coliforms and E. coli was achieved. Overall, this study highlights the potential of acidification with low level nitrite addition as an effective and simple method achieving multiple improvements in terms of sludge management.

  11. Significance of iron reduction for the therapy of chronic hepatitis C

    Directory of Open Access Journals (Sweden)

    Nožić Darko


    Full Text Available Background. It has been established that many patients with chronic hepatitis C have elevated serum iron, feritin levels and iron deposits in the liver. Therefore, the liver damage due to hepatitis C virus may be aggravated with iron overload. In many studies higher levels of iron in the blood and the liver were connected with the decreased response to interferon-alfa therapy for chronic viral hepatitis C. Recent introduction of pegylated interferons plus ribavirin has improved the therapeutic response, so it is now possible to cure more than 50% of the patients. Case report. Three patients with chronic hepatitis C and iron overload were presented. Iron reduction therapy using phlebotomy or eritrocytapheresis with plasmapheresis was done at different times in regard to specific antiviral therapy or as a sole therapy. Conclusion. It has been shown that iron reduction, sole or combined with antiviral therapy, led to the deacreased aminotransferase serum activity and might have slow down the evolution of chronic hepatitis C viral infection.

  12. Identification of Flap Motion Parameters for Vibration Reduction in Helicopter Rotors with Multiple Active Trailing Edge Flaps


    Dalli, Uğbreve;ur; Yüksel, Şcedilefaatdin


    An active control method utilizing the multiple trailing edge flap configuration for rotorcraft vibration suppression and blade loads control is presented. A comprehensive model for rotor blade with active trailing edge flaps is used to calculate the vibration characteristics, natural frequencies and mode shapes of any complex composite helicopter rotor blade. A computer program is developed to calculate the system response, rotor blade root forces and moments under aerodynamic forcing condit...

  13. Handbook Of Noise And Vibration

    International Nuclear Information System (INIS)


    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.

  14. Technological significances to reduce the material problems. Feasibility of heat flux reduction

    International Nuclear Information System (INIS)

    Yamazaki, Seiichiro; Shimada, Michiya.


    For a divertor plate in a fusion power reactor, a high temperature coolant must be used for heat removal to keep thermal efficiency high. It makes the temperature and thermal stress of wall materials higher than the design limits. Issues of the coolant itself, e.g. burnout of high temperature water, will also become a serious problem. Sputtering erosion of the surface material will be a great concern of its lifetime. Therefore, it is necessary to reduce the heat and particle loads to the divertor plate technologically. The feasibility of some technological methods of heat reduction, such as separatrix sweeping, is discussed. As one of the most promising ideas, the methods of radiative cooling of the divertor plasma are summarized based on the recent results of large tokamaks. The feasibility of remote radiative cooling and gas divertor is discussed. The ideas are considered in recent design studies of tokamak power reactors and experimental reactors. By way of example, conceptual designs of divertor plate for the steady state tokamak power reactor are described. (author)

  15. Ground test for vibration control demonstrator (United States)

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


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

  16. Feed-forward adaptive system for vibration and sound radiation reduction phase I: architecture, definition, and specifications (United States)

    Concilio, Antonio; De Vivo, Luciano; Quaranta, V.


    Noise emission suppression problem is more and more absorbing mechanical designers' efforts, in the recent times. It is not only a matter of comfort, but also of people exposure noise limits. A significant step has been moved in Europe with the issue of the EU Green Paper: Future Noise Policy. Impact on external and internal environment is requested to be considered in industrial and civil design. Low frequency disturbances are hard to be treated by classical passive methods. Active noise control presents great potentialities. In the last years, significant improvements have been attained in the field of interior acoustics, with particular reference to aircraft. Microphones and loudspeakers - based active systems have been put on the market, while interesting alternatives have been proved to be effective, implementing Smart Materials and Structures related concepts. The authors of this paper and of its continuation have been working for a long time inside the themes related to the noise control in aircraft cabins. Thin-walled beams have a certain importance; they are representative of fuselage range. This document deals with the design and the specifications definition, concerning a system addressed to the minimization of the vibration level of, or the sound power level radiated by , a general structure; in the specific case, a thin-walled beam was selected as test article, fully representative of general complex elements. The structure is identified and characterized through its experimental response. The set-up for the active control measurements is then described in detail; the acquired transfer functions have been elaborated to predict the performance of the real active control system.

  17. Significant Reduction in the Incidence of Phlebitis with Buffered Versus Unbuffered Cephalothin (United States)

    Bergeron, Michel G.; Brusch, John L.; Barza, Michael; Weinstein, Louis


    Cephalothin (1 g every 2 h), buffered cephalothin, and diluent alone (5% dextrose in water) were each administered for 4 days intravenously to 12 volunteers in a double-blind crossover study. The incidence of phlebitis with buffered cephalothin was significantly lower than that with unbuffered drug (P < 0.01) and almost identical to the incidence with diluent alone. PMID:1267438

  18. [Smoking fewer cigarettes per day may determine a significant risk reduction in developing smoking attributable diseases? Is there a risk reduction for e-cigarette users?]. (United States)

    Pieri, Luca; Chellini, Elisabetta; Gorini, Giuseppe


    Among Italian smokers--about 10 millions in 2013--about 600,000 began using electronic cigarettes (e-cigs) in last years. About 10% of e-cig users quitted smoking tobacco, whereas the 90% was dual users. Among them, about three out of four decreased the number of cigarettes smoked per day (cig/day), but did not quit. How many fewer cigarettes a smoker has to smoke to obtain significant health benefits? Is there a threshold? In order to observe a significant 27% reduction in the risk of developing lung cancer, a smoker must reduce the number of cig/day by at least 50%, while for the other smoking-related diseases (acute myocardial infarction - AMI, stroke, chronic obstructive pulmonary diseases), halving the number of cig/day did not drive to a significant risk reduction. Even smoking 5 cig/day increases the risk of AMI, whereas it significantly lowers the risk of lung cancer. Obviously, quitting smoking is the best choice to highly reduce risks for all smoking-related diseases. Therefore, in order to achieve significant risk reductions, e-cig users should quit smoking as first choice, or, if they feel it is impossible to them, reduce the consumption of traditional cigarettes to less than 5 cig/day.

  19. Identification of Flap Motion Parameters for Vibration Reduction in Helicopter Rotors with Multiple Active Trailing Edge Flaps

    Directory of Open Access Journals (Sweden)

    Uğbreve;ur Dalli


    Full Text Available An active control method utilizing the multiple trailing edge flap configuration for rotorcraft vibration suppression and blade loads control is presented. A comprehensive model for rotor blade with active trailing edge flaps is used to calculate the vibration characteristics, natural frequencies and mode shapes of any complex composite helicopter rotor blade. A computer program is developed to calculate the system response, rotor blade root forces and moments under aerodynamic forcing conditions. Rotor blade system response is calculated using the proposed solution method and the developed program depending on any structural and aerodynamic properties of rotor blades, structural properties of trailing edge flaps and properties of trailing edge flap actuator inputs. Rotor blade loads are determined first on a nominal rotor blade without multiple active trailing edge flaps and then the effects of the active flap motions on the existing rotor blade loads are investigated. Multiple active trailing edge flaps are controlled by using open loop controllers to identify the effects of the actuator signal output properties such as frequency, amplitude and phase on the system response. Effects of using multiple trailing edge flaps on controlling rotor blade vibrations are investigated and some design criteria are determined for the design of trailing edge flap controller that will provide actuator signal outputs to minimize the rotor blade root loads. It is calculated that using the developed active trailing edge rotor blade model, helicopter rotor blade vibrations can be reduced up to 36% of the nominal rotor blade vibrations.

  20. LASR-Guided Variability Subtraction: The Linear Algorithm for Significance Reduction of Stellar Seismic Activity (United States)

    Horvath, Sarah; Myers, Sam; Ahlers, Johnathon; Barnes, Jason W.


    Stellar seismic activity produces variations in brightness that introduce oscillations into transit light curves, which can create challenges for traditional fitting models. These oscillations disrupt baseline stellar flux values and potentially mask transits. We develop a model that removes these oscillations from transit light curves by minimizing the significance of each oscillation in frequency space. By removing stellar variability, we prepare each light curve for traditional fitting techniques. We apply our model to $\\delta$-Scuti KOI-976 and demonstrate that our variability subtraction routine successfully allows for measuring bulk system characteristics using traditional light curve fitting. These results open a new window for characterizing bulk system parameters of planets orbiting seismically active stars.

  1. Significant reduction of repeat teen pregnancy in a comprehensive young parent program. (United States)

    Omar, H A; Fowler, A; McClanahan, K K


    To describe a comprehensive, multidisciplinary approach to teen mothers and their children that significantly reduces repeat pregnancies. Retrospective review of repeat teen pregnancy data. Young Parent Program (YPP) at a university-based health center. 1386 teen mothers between the ages of 11 and 19 who participated in the YPP for at least three years. Comprehensive Care: for both teen mother and her baby, including prenatal and postnatal care, preventive care, reproductive services, mental health, and acute care visits. Family counseling and similar services were also provided to siblings of the teen. CONTINUITY OF CARE: Patients are seen by the same staff and attending physicians on each visit. The treatment team includes physicians, nurses, social worker, nutritionist, and psychologist, all of whom are available to provide care at each visit. Flexible hours: Including evening clinic to allow teens to attend school or work during the day. Financial incentive: Patients with no insurance are given free contraceptives and a "no charge" clinic visit. Extensive contraceptive counseling is provided prior to start of contraceptive use and at every clinic visit. Routine telephone and/or mail reminders of appointments Rate of repeat teen pregnancy. Only 11(.79%) had repeat pregnancies. Older youth appeared more likely to repeat a pregnancy. Comprehensive intervention for teen mothers can be very successful in reducing repeat teen pregnancy in those teens who participate consistently in the program over a period of years.

  2. Assessment of treatment response to splint therapy and evaluation of TMJ function using joint vibration analysis in patients exhibiting TMJ disc displacement with reduction: A clinical study

    Directory of Open Access Journals (Sweden)

    Jyoti Devi


    Full Text Available Context, Aim, and Objectives: Diagnosis of temporomandibular joint (TMJ disc displacement with reduction (DDR is difficult. Literature combining different subjective parameters of TMJ function with an objective evaluation of TMJ function using joint vibration analysis (JVA is limited. Hence, the study was planned to diagnose temporomandibular disorder accurately, to do a subjective and objective evaluation of TMJ function, and to assess the effectiveness of different types of splint therapy over the conventional anterior repositioning appliance (ARA group. Design: Single-blind, randomized, comparative clinical trial conducted in thirty patients, 18–55 years of age, allocated to three groups, i.e., ARA conventional group, centric stabilization splint (CSS, and Soft splint (SS groups. Subjects and Methods: Preoperative values of comfortable mouth opening (CMO in mm, maximum mouth opening (MMO in mm, TMJ clicking and tenderness (grading 0–3, visual analog scale pain score (0–10 cm, and total energy (TE integral values of both TMJs using JVA were recorded. Postoperative values were taken at the time of delivery of splint at 1st, 2nd, 6th, and 10th week. Statistical Analysis and Results: Intergroup comparison – Kruskal–Wallis test showed no statistically significant difference in CMO, MMO, and TE values of right TMJs among three groups at any point. No significant difference was seen in TMJ clicking and tenderness among groups at any point of time except at 10 weeks and at 2 weeks, respectively, by Chi-square test. Intragroup comparison - Wilcoxon signed-rank test showed the significance of difference (P < 0.05* in postoperative visits for CMO, MMO, pain score, and TE values. Clinical effect size, extent, consistency, and percentage of cases showing improvement were maximum for CSS group. Conclusions: The study concludes that the use of JVA for diagnosis along with history and clinical examination increases the accuracy of the diagnosis of

  3. Implementation of pressurized air injection system in a Kaplan prototype for the reduction of vibration caused by tip vortex cavitation (United States)

    Rivetti, A.; Angulo, M.; Lucino, C.; Hene, M.; Capezio, O.; Liscia, S.


    Blade tip cavitation is a well-known phenomenon that affects the performance of large-diameter Kaplan turbines and induces structural vibration. Injection of pressurized air has been found to yield promising results in reducing those damaging effects. In this work, the results of an experimental test of air injection on a 9.5-m-diameter Kaplan turbine are reported. Experiments were performed for several load conditions and for two different net heads. Accelerations, pressure pulsation and noise emission were monitored for every tested condition. Results show that, at the expense of a maximum efficiency drop of 0.2%, air injection induces a decrease on the level of vibration from 57% up to 84%, depending on the load condition. Such decrease is seen to be proportional to the air flow rate, in the range from 0.06 to 0.8‰ (respect to the discharge at the best efficiency point).

  4. Significant reduction of saturation magnetization and microwave-reflection loss in barium-natural ferrite via Nd3+ substitution (United States)

    Widanarto, W.; Ardenti, E.; Ghoshal, S. K.; Kurniawan, C.; Effendi, M.; Cahyanto, W. T.


    To minimize the signal degradation, many electronic devices require efficient microwave absorbers with very low reflection-losses within the X-band. We prepared a series of trivalent neodymium-ion (Nd3+) substituted barium-natural ferrite using a modified solid-state reaction method. The effect of the Nd3+-ion content on the structure, surface morphology, magnetic properties, and microwave reflection loss was studied. The composites were characterized using X-ray diffraction, a vibrating sample magnetometer, scanning electron microscopy, and a vector network analyzer. The XRD patterns of the sample without Nd3+ reveal the presence of BaFe12O19 (hexagonal) and BaFe2O4 (rhombohedral) phases. Furthermore, a new hexagonal crystal phase of Ba6Nd2Fe4O15 appeared after substituting Nd3+. The average size of the prepared barium-natural ferrite particles was estimated to be between 0.4 and 0.8 μm. Both saturation magnetization and microwave reflection losses of these barium-ferrites were significantly reduced by increasing the Nd3+ content.

  5. Active vibration reduction of a flexible structure bonded with optimised piezoelectric pairs using half and quarter chromosomes in genetic algorithms

    International Nuclear Information System (INIS)

    Daraji, A H; Hale, J M


    The optimal placement of sensors and actuators in active vibration control is limited by the number of candidates in the search space. The search space of a small structure discretized to one hundred elements for optimising the location of ten actuators gives 1.73 × 10 13 possible solutions, one of which is the global optimum. In this work, a new quarter and half chromosome technique based on symmetry is developed, by which the search space for optimisation of sensor/actuator locations in active vibration control of flexible structures may be greatly reduced. The technique is applied to the optimisation for eight and ten actuators located on a 500×500mm square plate, in which the search space is reduced by up to 99.99%. This technique helps for updating genetic algorithm program by updating natural frequencies and mode shapes in each generation to find the global optimal solution in a greatly reduced number of generations. An isotropic plate with piezoelectric sensor/actuator pairs bonded to its surface was investigated using the finite element method and Hamilton's principle based on first order shear deformation theory. The placement and feedback gain of ten and eight sensor/actuator pairs was optimised for a cantilever and clamped-clamped plate to attenuate the first six modes of vibration, using minimization of linear quadratic index as an objective function.

  6. Anti-vibration gloves? (United States)

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


    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.

  7. Reduction of torsional vibrations of hybrid drives when using a low number of cylinders; Drehschwingungsberuhigung von Hybridantrieben mit niedrigen Zylinderzahlen

    Energy Technology Data Exchange (ETDEWEB)

    Hohenberg, Guenter [IVD Prof. Hohenberg GmbH, Graz (Austria); Beidl, Christian [Technische Univ. Darmstadt (Germany). VKM; Hoefler, Dieter [tectos gmbh, Graz (Austria)


    Plug-in hybrid drives will be, in the foreseeable future, the dominant variant for the electrification of vehicles, with the trend clearly pointing to combustion engines with a low number of cylinders and low engine operating speeds. However, the considerable torsional vibration and its impact on the drive train as well as the engine mount pose a problem. The conventional mechanical solutions with dual mass flywheels and pendulum support etc. have clearly reached their limit when it comes to improving the noise vibration harshness (NVH) behavior. Operating the drive engine with low speed values which are relevant for the fuel consumption is therefore only possible to a limited extent. This paper introduces a technique as a solution to the problem, where the excitation frequency can be doubled with the existing E-motor by generating additional torque pulses. This will achieve the excitation of the drive train and the engine mount as would be the case with a combustion engine with twice the number of cylinders. This technique, referred to as directE strategy, is particularly interesting for 2 und 3-cylinder engines. By combining the individual components into a highly integrated directE hybrid module a simple combination of existing combustion engines and gearboxes can be implemented. This paper describes the technique in more detail, which is followed by a discussion of its advantages, disadvantages and the first practical results. (orig.)

  8. Vibrational spectroscopy (United States)

    Umesh P. Agarwal; Rajai Atalla


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

  9. Experimental Research on Vibrations of Double Harmonic Gear Transmission

    Directory of Open Access Journals (Sweden)

    Sava Ianici


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

  10. A clip-based protocol for breast boost radiotherapy provides clear target visualisation and demonstrates significant volume reduction over time

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Lorraine [Department of Radiation Oncology, Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Cox, Jennifer [Department of Radiation Oncology, Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Faculty of Health Sciences, University of Sydney, Sydney, New South Wales (Australia); Morgia, Marita [Department of Radiation Oncology, Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Atyeo, John [Faculty of Health Sciences, University of Sydney, Sydney, New South Wales (Australia); Lamoury, Gillian [Department of Radiation Oncology, Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia)


    The clinical target volume (CTV) for early stage breast cancer is difficult to clearly identify on planning computed tomography (CT) scans. Surgical clips inserted around the tumour bed should help to identify the CTV, particularly if the seroma has been reabsorbed, and enable tracking of CTV changes over time. A surgical clip-based CTV delineation protocol was introduced. CTV visibility and its post-operative shrinkage pattern were assessed. The subjects were 27 early stage breast cancer patients receiving post-operative radiotherapy alone and 15 receiving post-operative chemotherapy followed by radiotherapy. The radiotherapy alone (RT/alone) group received a CT scan at median 25 days post-operatively (CT1rt) and another at 40 Gy, median 68 days (CT2rt). The chemotherapy/RT group (chemo/RT) received a CT scan at median 18 days post-operatively (CT1ch), a planning CT scan at median 126 days (CT2ch), and another at 40 Gy (CT3ch). There was no significant difference (P = 0.08) between the initial mean CTV for each cohort. The RT/alone cohort showed significant CTV volume reduction of 38.4% (P = 0.01) at 40 Gy. The Chemo/RT cohort had significantly reduced volumes between CT1ch: median 54 cm{sup 3} (4–118) and CT2ch: median 16 cm{sup 3}, (2–99), (P = 0.01), but no significant volume reduction thereafter. Surgical clips enable localisation of the post-surgical seroma for radiotherapy targeting. Most seroma shrinkage occurs early, enabling CT treatment planning to take place at 7 weeks, which is within the 9 weeks recommended to limit disease recurrence.

  11. A clip-based protocol for breast boost radiotherapy provides clear target visualisation and demonstrates significant volume reduction over time

    International Nuclear Information System (INIS)

    Lewis, Lorraine; Cox, Jennifer; Morgia, Marita; Atyeo, John; Lamoury, Gillian


    The clinical target volume (CTV) for early stage breast cancer is difficult to clearly identify on planning computed tomography (CT) scans. Surgical clips inserted around the tumour bed should help to identify the CTV, particularly if the seroma has been reabsorbed, and enable tracking of CTV changes over time. A surgical clip-based CTV delineation protocol was introduced. CTV visibility and its post-operative shrinkage pattern were assessed. The subjects were 27 early stage breast cancer patients receiving post-operative radiotherapy alone and 15 receiving post-operative chemotherapy followed by radiotherapy. The radiotherapy alone (RT/alone) group received a CT scan at median 25 days post-operatively (CT1rt) and another at 40 Gy, median 68 days (CT2rt). The chemotherapy/RT group (chemo/RT) received a CT scan at median 18 days post-operatively (CT1ch), a planning CT scan at median 126 days (CT2ch), and another at 40 Gy (CT3ch). There was no significant difference (P = 0.08) between the initial mean CTV for each cohort. The RT/alone cohort showed significant CTV volume reduction of 38.4% (P = 0.01) at 40 Gy. The Chemo/RT cohort had significantly reduced volumes between CT1ch: median 54 cm 3 (4–118) and CT2ch: median 16 cm 3 , (2–99), (P = 0.01), but no significant volume reduction thereafter. Surgical clips enable localisation of the post-surgical seroma for radiotherapy targeting. Most seroma shrinkage occurs early, enabling CT treatment planning to take place at 7 weeks, which is within the 9 weeks recommended to limit disease recurrence

  12. Significant Improvement Selected Mediators of Inflammation in Phenotypes of Women with PCOS after Reduction and Low GI Diet

    Directory of Open Access Journals (Sweden)

    Małgorzata Szczuko


    Full Text Available Many researchers suggest an increased risk of atherosclerosis in women with polycystic ovary syndrome. In the available literature, there are no studies on the mediators of inflammation in women with PCOS, especially after dietary intervention. Eicosanoids (HETE and HODE were compared between the biochemical phenotypes of women with PCOS (normal and high androgens and after the 3-month reduction diet. Eicosanoid profiles (9(S-HODE, 13(S-HODE, 5(S-HETE, 12(S-HETE, 15(S-HETE, 5(S-oxoETE, 16(R-HETE, 16(S-HETE and 5(S, 6(R-lipoxin A4, 5(S, 6(R, 15(R-lipoxin A4 were extracted from 0.5 ml of plasma using solid-phase extraction RP-18 SPE columns. The HPLC separations were performed on a 1260 liquid chromatograph. No significant differences were found in the concentration of analysed eicosanoids in phenotypes of women with PCOS. These women, however, have significantly lower concentration of inflammatory mediators than potentially healthy women from the control group. Dietary intervention leads to a significant (p<0.01 increase in the synthesis of proinflammatory mediators, reaching similar levels as in the control group. The development of inflammatory reaction in both phenotypes of women with PCOS is similar. The pathways for synthesis of proinflammatory mediators in women with PCOS are dormant, but can be stimulated through a reduction diet. Three-month period of lifestyle change may be too short to stimulate the pathways inhibiting inflammatory process.

  13. Editor's choice--Use of disposable radiation-absorbing surgical drapes results in significant dose reduction during EVAR procedures. (United States)

    Kloeze, C; Klompenhouwer, E G; Brands, P J M; van Sambeek, M R H M; Cuypers, P W M; Teijink, J A W


    Because of the increasing number of interventional endovascular procedures with fluoroscopy and the corresponding high annual dose for interventionalists, additional dose-protecting measures are desirable. The purpose of this study was to evaluate the effect of disposable radiation-absorbing surgical drapes in reducing scatter radiation exposure for interventionalists and supporting staff during an endovascular aneurysm repair (EVAR) procedure. This was a randomized control trial in which 36 EVAR procedures were randomized between execution with and without disposable radiation-absorbing surgical drapes (Radpad: Worldwide Innovations & Technologies, Inc., Kansas City, US, type 5511A). Dosimetric measurements were performed on the interventionalist (hand and chest) and theatre nurse (chest) with and without the use of the drapes to obtain the dose reduction and effect on the annual dose caused by the drapes. Use of disposable radiation-absorbing surgical drapes resulted in dose reductions of 49%, 55%, and 48%, respectively, measured on the hand and chest of the interventionalist and the chest of the theatre nurse. The use of disposable radiation-absorbing surgical drapes significantly reduces scatter radiation exposure for both the interventionalist and the supporting staff during EVAR procedures. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  14. A projection-based model reduction strategy for the wave and vibration analysis of rotating periodic structures (United States)

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


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

  15. Vibration of hydraulic machinery

    CERN Document Server

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


    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...

  16. Vibration Analysis of Beam and Block Precast Slab System due to Human Vibrations (United States)

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


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

  17. Classification of Non-Small Cell Lung Cancer Using Significance Analysis of Microarray-Gene Set Reduction Algorithm

    Directory of Open Access Journals (Sweden)

    Lei Zhang


    Full Text Available Among non-small cell lung cancer (NSCLC, adenocarcinoma (AC, and squamous cell carcinoma (SCC are two major histology subtypes, accounting for roughly 40% and 30% of all lung cancer cases, respectively. Since AC and SCC differ in their cell of origin, location within the lung, and growth pattern, they are considered as distinct diseases. Gene expression signatures have been demonstrated to be an effective tool for distinguishing AC and SCC. Gene set analysis is regarded as irrelevant to the identification of gene expression signatures. Nevertheless, we found that one specific gene set analysis method, significance analysis of microarray-gene set reduction (SAMGSR, can be adopted directly to select relevant features and to construct gene expression signatures. In this study, we applied SAMGSR to a NSCLC gene expression dataset. When compared with several novel feature selection algorithms, for example, LASSO, SAMGSR has equivalent or better performance in terms of predictive ability and model parsimony. Therefore, SAMGSR is a feature selection algorithm, indeed. Additionally, we applied SAMGSR to AC and SCC subtypes separately to discriminate their respective stages, that is, stage II versus stage I. Few overlaps between these two resulting gene signatures illustrate that AC and SCC are technically distinct diseases. Therefore, stratified analyses on subtypes are recommended when diagnostic or prognostic signatures of these two NSCLC subtypes are constructed.

  18. Significant reduction of antibiotic use in the community after a nationwide campaign in France, 2002-2007.

    Directory of Open Access Journals (Sweden)

    Elifsu Sabuncu


    Full Text Available BACKGROUND: Overuse of antibiotics is the main force driving the emergence and dissemination of bacterial resistance in the community. France consumes more antibiotics and has the highest rate of beta-lactam resistance in Streptococcus pneumoniae than any other European country. In 2001, the government initiated "Keep Antibiotics Working"; the program's main component was a campaign entitled "Les antibiotiques c'est pas automatique" ("Antibiotics are not automatic" launched in 2002. We report the evaluation of this campaign by analyzing the evolution of outpatient antibiotic use in France 2000-2007, according to therapeutic class and geographic and age-group patterns. METHODS AND FINDINGS: This evaluation is based on 2000-2007 data, including 453,407,458 individual reimbursement data records and incidence of flu-like syndromes (FLSs. Data were obtained from the computerized French National Health Insurance database and provided by the French Sentinel Network. As compared to the preintervention period (2000-2002, the total number of antibiotic prescriptions per 100 inhabitants, adjusted for FLS frequency during the winter season, changed by -26.5% (95% confidence interval [CI] -33.5% to -19.6% over 5 years. The decline occurred in all 22 regions of France and affected all antibiotic therapeutic classes except quinolones. The greatest decrease, -35.8% (95% CI -48.3% to -23.2%, was observed among young children aged 6-15 years. A significant change of -45% in the relationship between the incidence of flu-like syndromes and antibiotic prescriptions was observed. CONCLUSIONS: The French national campaign was associated with a marked reduction of unnecessary antibiotic prescriptions, particularly in children. This study provides a useful method for assessing public-health strategies designed to reduce antibiotic use.

  19. Parent material and weldments degradation on SASOL reduction reactors due to combined effect of thermal fatigue, vibration and hydrogen attack

    International Nuclear Information System (INIS)

    Borla, Jan Z.


    All six installed reduction reactors showed the same failure pattern, which can be attributed to inadequate original design, material degradation due to service conditions and improper maintenance activities. Service is typically low frequency fatigue load conditions with changes of pressure, temperature and batch load. All revealed defects severely affected the integrity of the pressure envelope and vessels were classified for major repair work with subsequent in situ monitoring program. The justification for such extensive and costly repair required a positive evaluation of the current condition of equipment. After complete study, a report was prepared which included the fitness for purpose evaluation, remaining life assessment and recommendation for future field inspections. All reactors were found to be suitable for repair. Within the scope of repair a number of critical elements were redesigned and replaced. The repair was successful and all reactors were put back into operation. Unique expertise was obtained regarding setting the parameters of dehydrogenation in reference to the heavy wall items. Taking replicas and surface sampling appeared to be very reliable and simple tools in monitoring the condition of pressure envelope. For the purpose of future inspection shutdowns specific inspection requirements were put in place to ensure continuous monitoring of the vessel integrity

  20. Vibrations of rotating machinery

    CERN Document Server

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


    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...

  1. Mitigation of Ground Vibration by Double Sheet-pile Walls

    DEFF Research Database (Denmark)

    Andersen, Lars; Frigaard, Peter; Augustesen, Anders


    Open trenches are an effective means of vibration mitigation, but they cannot be established in practice. When the trenches are covered by a concrete pavement, part of the efficiency may be lost. However, the present analysis indicates that barriers of this kind may still lead to a significant re...... reduction of the horizontal and vertical vibrations caused by traffic at a nearby road or railway....

  2. Design and test on vibration reduction for knife driving device of combine harvester%联合收获机切割器驱动装置减振设计与试验

    Institute of Scientific and Technical Information of China (English)

    王志明; 马广; 吕彭民; 陈霓


    Summary In the knife driving system of combine harvester,a slider-crank mechanism with a simple structure is used for driving the cutter bar.A low-cost balance mass is generally used in this mechanism to offset the unbalanced force for vibration reduction.The vibration characteristics of the knife driving system should be clarified in order to develop a method to reduce the vibration.Furthermore,it is necessary to develop a design theory of the knife driving system of combine harvesters in order to derive the control parameters of the balance weights used for vibration reduction. The mechanical model of the knife driving device that is equipped with a slider-crank mechanism was constructed in order to derive the control parameters of the balance weights,such as the mass and the location of the balance mass.The simulation conditions of the model,which reflect the condition of the actual combine harvester, are listed.The angular velocity was equivalent to the rotation number of the crank wheel and was around 73 rad/s (700 r/min)in the clockwise direction.Vibration experiment was done with the type 4LZS-1.8 combine harvester. The vibration acceleration was measured using the preprocessing and cutting device of the actual combine harvester (the divider and conveying unit did not work;only the knife driving system worked).The interval time in calculation was set to 1 ms according to the sampling time of the measurement of the acceleration.The simulated inertia force was compared with measured acceleration in time series in order to evaluate the vibration model of the knife driving system.In the state without a balance mass,the simulation could express the vibration of the knife driving system well by comparing it with the measured acceleration.Consequently,this mechanical model could express the vibration characteristics of the knife driving system.The root mean square (RMS) value of the inertia force was simulated in the state with the balance mass in order to examine

  3. Significant advantages of sulfur-doped graphene in neutral media as electrocatalyst for oxygen reduction comparing with Pt/C (United States)

    Shi, Xinxin; Zhang, Jiaona; Huang, Tinglin


    Sulfur-doped graphene (SDG) has been found to be an efficient electrocatalyst for oxygen reduction reaction. However, previous studies on the catalytic activity of SDG have been mainly confined to O2-saturated alkaline media which is a typical alkaline fuel cell environment. Air-cathode microbial fuel cells (ACMFCs), as a novel energy conversion and wastewater treatment technology, use the oxygen from air as cathodic reactant in neutral media with low concentration of O2. Thus, it is meaningful to explore the catalytic performance of SDG in such ACMFC environment. The result showed that in ACMFC environment, the peak current density of SDG in CV test was surprisingly 4.5 times higher than that of Pt/C, indicating a much stronger catalytic activity of SDG. Moreover, SDG exhibited a stronger tolerance against the crossover of glucose (a typical anodic fuel in ACMFC) and better stability than Pt/C in neutral media.

  4. Vibration mixer

    Energy Technology Data Exchange (ETDEWEB)

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


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

  5. Development of adaptive helicopter seat systems for aircrew vibration mitigation (United States)

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


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

  6. Significant rising antibody titres to influenza A are associated with an acute reduction in milk yield in cattle. (United States)

    Crawshaw, Timothy R; Brown, Ian H; Essen, Steve C; Young, Stuart C L


    Sporadic cases of an acute fall in milk production, "milk drop", were investigated in a Holstein Friesian dairy herd in Devon. The investigation was a case control study with two controls per case. Paired blood samples demonstrated that rising antibody titres to human influenza A/England/333/80 (H1N1) and human influenza A/Eng/427/88 (H3N2) were associated with an acute fall in milk production. Rising titres to bovine respiratory syncytial virus (BRSV), bovine virus diarrhoea virus (BVD), infectious bovine rhinotracheitis (IBR) and parainfluenza virus 3 (PI3) were not associated with an acute fall in milk production. Cases with rises in antibody to influenza A had significantly higher respiratory scores and rectal temperatures than their controls. The mean loss of milk production for the cases with rises in antibody to influenza A compared to their controls was 159.9L. This study provides further evidence that influenza A persists in cattle and causes clinical disease.

  7. Significant reductions in oil quality and lipid content of oilseed rape (Brassica napus L.) under climate change

    DEFF Research Database (Denmark)

    Namazkar, Shahla; Egsgaard, Helge; Frenck, Georg


    Despite of the potential importance to food and bioenergy purposes, effects from climate change on plant oil quality have hardly been characterized.On a global basis Brassica napus L., rapeseed or oilseed rape, is the second largest source of vegetable oil after soybean and the predominant oil crop...... in Europe. We found significant changes in oil quality and quantity of four cultivars of oilseed rape grown in five future climate scenarios with elevated [CO2], [O-3] temperature and combinations hereof (similar to RCP8.5,(1)). Populations of the cultivars were grown under ambient and climate change...... conditions in a climate-phytotron. The treatments were ambient (360 ppm CO2, 19/12 degrees C (day/night), 20/20 ppb O-3 (day/night)), all factors elevated (650 ppm CO2, 24/17 degrees C, 60/20 ppb O-3), as well as two- and single-factor treatments with the elevated factors.The overall trend was that oil...

  8. Significant Reduction in Helicobacter pylori Load in Humans with Non-viable Lactobacillus reuteri DSM17648: A Pilot Study. (United States)

    Holz, Caterina; Busjahn, Andreas; Mehling, Heidrun; Arya, Stefanie; Boettner, Mewes; Habibi, Hajar; Lang, Christine


    Reducing the amount of Helicobacter pylori in the stomach by selective bacterial-bacterial cell interaction was sought as an effective and novel method for combating the stomach pathogen. Lactobacillus reuteri DSM17648 was identified as a highly specific binding antagonist to H. pylori among more than 700 wild-type strains of Lactobacillus species. Applying a stringent screening procedure, the strain DSM17648 was identified as selective binder to H. pylori cells under in vivo gastric conditions. The strain DSM17648 co-aggregates the pathogen in vivo and in vitro. The specific co-aggregation occurs between Lact. reuteri DSM17648 and different H. pylori strains and serotypes, as well as H. heilmannii, but not with Campylobacter jejuni or other commensal oral and intestinal bacteria. Lact. reuteri DSM17648 was shown in a proof-of-concept single-blinded, randomized, placebo-controlled pilot study to significantly reduce the load of H. pylori in healthy yet infected adults. Reducing the amount of H. pylori in the stomach by selective bacterial-bacterial cell interaction might be an effective and novel method for combating the stomach pathogen. Lact. reuteri DSM17648 might prove useful as an adhesion blocker in antibiotic-free H. pylori therapies.

  9. Applying Low-Frequency Vibration for the Experimental Investigation of Clutch Hub Forming

    Directory of Open Access Journals (Sweden)

    De’an Meng


    Full Text Available A vibration-assisted plastic-forming method was proposed, and its influence on clutch hub forming process was investigated. The experiments were conducted on a vibration-assisted hydraulic extrusion press with adjustable frequency and amplitude. Vibration frequency and amplitude were considered in investigating the effect of vibration on forming load and surface quality. Results showed that applying vibration can effectively reduce forming force and improve surface quality. The drop in forming load was proportional to the vibration frequency and amplitude, and the load decreased by up to 25%. Such reduction in forming load raised with amplitude increase because the increase in amplitude would accelerate punch relative speed, which then weakened the adhesion between workpiece and dies. By increasing the vibration frequency, the punch movement was enhanced, and the number of attempts to drag the lubricant out of the pits was increased. In this manner, the lubrication condition was improved greatly. The 3D surface topography testing confirmed the assumption. Moreover, vibration frequency exerted a more significant effect on the forming load reduction than vibration amplitude.

  10. Autologous inferior dermal sling (autoderm) with concomitant skin-envelope reduction mastectomy: an excellent surgical choice for women with macromastia and clinically significant ptosis. (United States)

    Dietz, Jill; Lundgren, P; Veeramani, A; O'Rourke, C; Bernard, S; Djohan, R; Larson, J; Isakov, R; Yetman, R


    Skin-sparing mastectomy and prosthetic reconstruction can be complicated by poor surgical outcomes in large-breasted, obese women. This article describes a single surgeon's experience comparing conventional skin-sparing mastectomy (SSM) and skin-reduction mastectomy using an autologous vascularized inferior dermal/cutaneous sling (autoderm). From July 2007 to May 2012, patients undergoing skin-sparing mastectomy were evaluated for surgical outcomes. After July 2009, the surgeon performed skin-reduction mastectomies with autoderm (SRM-AD) on all patients with macromastia or grade 3-4 ptosis. Remaining patients in this time period (SSM-cont) underwent conventional skin-sparing mastectomies while all previous patients (historical) also underwent skin-sparing mastectomies (SSM-hist). A predictive model was used to compare the large historical patients (who would have had reduction mastectomy if available) with the smaller historical patients to evaluate the effect of the procedure. Body mass index (BMI) and specimen weight were higher in both the SRM group and large historical group. The hazard ratio for having skin-reduction mastectomy was 0.53 (P = 0.51) compared with the historical group. There was a total of 16 complications for the whole study. Smoking was the only significant risk factor. This study shows that mastectomy with prosthetic reconstruction using a skin-reduction technique with autoderm can be done safely with a low complication rate and improved cosmetic outcomes in the traditionally "at-risk" group of women with high BMI and large ptotic breasts.

  11. Ship Vibrations

    DEFF Research Database (Denmark)

    Sørensen, Herman


    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...

  12. Tool-specific performance of vibration-reducing gloves for attenuating fingers-transmitted vibration (United States)

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


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

  13. Effect of shelf aging on vibration transmissibility of anti-vibration gloves (United States)

    SHIBATA, Nobuyuki


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

  14. Reduction of belt CVT gear noise by gear train modification. Optimize vibration characteristics of gear train; Belt CVT no gear noise teigen gijutsu. Gear train shindo tokusei no saitekika

    Energy Technology Data Exchange (ETDEWEB)

    Arimatsu, M; Kawakami, T [Nissan Motor Co. Ltd., Tokyo (Japan)


    With the reduction of vehicle noise, the requirements for an efficient method to reduce transmission gear noise have become stronger yearly. So far efforts to reduce gear noise have generally focused on ways of improving the gears themselves. In addition to these traditional methods, it proved very beneficial to us to optimize the gear train structure. Nissan has just released the new Belt CVT for 2.0L Front wheel drive vehicles. We have been analyzing vibration of the gear train by using a finite element model since the early development stage, and we could achieve the quiet gears effectively. 2 refs., 9 figs.

  15. Integrating the Public in Mosquito Management: Active Education by Community Peers Can Lead to Significant Reduction in Peridomestic Container Mosquito Habitats (United States)

    Healy, Kristen; Hamilton, George; Crepeau, Taryn; Healy, Sean; Unlu, Isik; Farajollahi, Ary; Fonseca, Dina M.


    Mosquito species that utilize peridomestic containers for immature development are commonly aggressive human biters, and because they often reach high abundance, create significant nuisance. One of these species, the Asian tiger mosquito Aedes albopictus, is an important vector of emerging infectious diseases, such as dengue, chikungunya, and Zika fevers. Integrated mosquito management (IMM) of Ae. albopictus is particularly difficult because it requires access to private yards in urban and suburban residences. It has become apparent that in the event of a public health concern due to this species, homeowners will have to be active participants in the control process by reducing mosquito habitats in their properties, an activity known as source reduction. However, limited attempts at quantifying the effect of source reduction by homeowners have had mixed results. Of note, many mosquito control programs in the US have some form of education outreach, however the primary approach is often passive focusing on the distribution of education materials as flyers. In 2010, we evaluated the use of active community peer education in a source reduction program, using AmeriCorps volunteers. The volunteers were mobilized over a 4-week period, in two areas with approximately 1,000 residences each in urban Mercer and suburban Monmouth counties in New Jersey, USA. The volunteers were first provided training on peridomestic mosquitoes and on basic approaches to reducing the number of container habitats for mosquito larvae in backyards. Within the two treatment areas the volunteers successfully engaged 758 separate homes. Repeated measures analysis of variance showed a significant reduction in container habitats in the sites where the volunteers actively engaged the community compared to untreated control areas in both counties. Our results suggest that active education using community peer educators can be an effective means of source reduction, and a critical tool in the arsenal

  16. Input Shaping to Reduce Solar Array Structural Vibrations (United States)

    Doherty, Michael J.; Tolson, Robert J.


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

  17. Significant reduction in vancomycin-resistant enterococcus colonization and bacteraemia after introduction of a bleach-based cleaning-disinfection programme. (United States)

    Grabsch, E A; Mahony, A A; Cameron, D R M; Martin, R D; Heland, M; Davey, P; Petty, M; Xie, S; Grayson, M L


    Vancomycin-resistant enterococcus (VRE) colonization and infection have increased at our hospital, despite adherence to standard VRE control guidelines. We implemented a multi-modal, hospital-wide improvement programme including a bleach-based cleaning-disinfection programme ('Bleach-Clean'). VRE colonization, infection and environmental contamination were compared pre and post implementation. The programme included a new product (sodium hypochlorite 1000 ppm + detergent), standardized cleaning-disinfection practices, employment of cleaning supervisors, and modified protocols to rely on alcohol-based hand hygiene and sleeveless aprons instead of long-sleeved gowns and gloves. VRE was isolated using chromogenic agar and/or routine laboratory methods. Outcomes were assessed during the 6 months pre and 12 months post implementation, including proportions (per 100 patients screened) of VRE colonization in high-risk wards (HRWs: intensive care, liver transplant, renal, haematology/oncology); proportions of environmental contamination; and episodes of VRE bacteraemia throughout the entire hospital. Significant reductions in newly recognized VRE colonizations (208/1948 patients screened vs 324/4035, a 24.8% reduction, P = 0.001) and environmental contamination (66.4% reduction, P = 0.012) were observed, but the proportion of patients colonized on admission was stable. The total burden of inpatients with VRE in the HRWs also declined (median percentage of colonized inpatients per week, 19.4% vs 17.3%, P = 0.016). Hospital-wide VRE bacteraemia declined from 14/2935 patients investigated to 5/6194 (83.1% reduction; P Clean programme was associated with marked reductions in new VRE colonizations in high-risk patients, and VRE bacteraemia across the entire hospital. These findings have important implications for VRE control in endemic healthcare settings. Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  18. Urban vibrations

    DEFF Research Database (Denmark)

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


    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...

  19. Suicide in Recent Onset Psychosis Revisited: Significant Reduction of Suicide Rate over the Last Two Decades - A Replication Study of a Dutch Incidence Cohort.

    Directory of Open Access Journals (Sweden)

    Stynke Castelein

    Full Text Available This study aims to compare the suicide risk over the past decade following recent onset psychosis to findings from the eighties and nineties in the same catchment area and to identify predictors of suicide in the context of the Psychosis Recent Onset Groningen-Survey (PROGR-S. A medical file search was carried out to determine the current status of all patients admitted between 2000 and 2009. The suicide rate was compared with a study executed in 1973-1988 in the same catchment area. Predictors of suicide were investigated using Cox regression. The status of 424 of the 614 patients was known in July 2014. Suicide occurred in 2.4% of patients with psychosis disorders (n = 10; mean follow-up 5.6 years; 6 out of 10 suicides took place within two years. Within two decades, the suicide rate dropped from 11% (follow-up 15 years, 8.5% after 5 years to 2.4%. The Standardized Mortality Rate (SMR of suicides compared with the general population was 41.6. A higher age was the only significant predictor for suicide. Neuroticism, living situation, disorganized and negative symptoms, and passive coping style all showed a trend for significance. A significant reduction in the suicide rate was found for people with psychosis over the past decades. Given the high SMR, suicide research should be given the highest priority. Identifying predictors may contribute to further reduction of suicide among patients with psychosis.

  20. The significance for epidemiological studies anti-measles antibody detection examined by enzyme immunoassay (EIA) and plaque reduction neutralization test (PRNT). (United States)

    Siennicka, Joanna; Częścik, Agnieszka; Trzcińska, Agnieszka


    The paper discusses the role of anti-measles antibodies for protection and significance for epidemiological studies determination of antibodies by different serological methods. The comparison of anti-measles virus antibodies levels measured by enzyme immunoassay (EIA) and Plaque Reduction Neutralization Test (PRNT) was described. It was found that the 200 mIU/ml of anti-measles activity measured by PRNT (level protection against symp- tomatic disease) is equivalent of 636 mIU/ml measured by EIA (Enzygnost®Anti-Measles Virus/IgG, Simens).

  1. Enhancement to Non-Contacting Stress Measurement of Blade Vibration Frequency (United States)

    Platt, Michael; Jagodnik, John


    A system for turbo machinery blade vibration has been developed that combines time-of-arrival sensors for blade vibration amplitude measurement and radar sensors for vibration frequency and mode identification. The enabling technology for this continuous blade monitoring system is the radar sensor, which provides a continuous time series of blade displacement over a portion of a revolution. This allows the data reduction algorithms to directly calculate the blade vibration frequency and to correctly identify the active modes of vibration. The work in this project represents a significant enhancement in the mode identification and stress calculation accuracy in non-contacting stress measurement system (NSMS) technology when compared to time-of-arrival measurements alone.

  2. Active vibration isolation of a rigidly mounted turbo pump

    NARCIS (Netherlands)

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


    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

  3. 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)


    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.)

  4. A New Bioinspired Perchlorate Reduction Catalyst with Significantly Enhanced Stability via Rational Tuning of Rhenium Coordination Chemistry and Heterogeneous Reaction Pathway. (United States)

    Liu, Jinyong; Han, Mengwei; Wu, Dimao; Chen, Xi; Choe, Jong Kwon; Werth, Charles J; Strathmann, Timothy J


    Rapid reduction of aqueous ClO4(-) to Cl(-) by H2 has been realized by a heterogeneous Re(hoz)2-Pd/C catalyst integrating Re(O)(hoz)2Cl complex (hoz = oxazolinyl-phenolato bidentate ligand) and Pd nanoparticles on carbon support, but ClOx(-) intermediates formed during reactions with concentrated ClO4(-) promote irreversible Re complex decomposition and catalyst deactivation. The original catalyst design mimics the microbial ClO4(-) reductase, which integrates Mo(MGD)2 complex (MGD = molybdopterin guanine dinucleotide) for oxygen atom transfer (OAT). Perchlorate-reducing microorganisms employ a separate enzyme, chlorite dismutase, to prevent accumulation of the destructive ClO2(-) intermediate. The structural intricacy of MGD ligand and the two-enzyme mechanism for microbial ClO4(-) reduction inspired us to improve catalyst stability by rationally tuning Re ligand structure and adding a ClOx(-) scavenger. Two new Re complexes, Re(O)(htz)2Cl and Re(O)(hoz)(htz)Cl (htz = thiazolinyl-phenolato bidentate ligand), significantly mitigate Re complex decomposition by slightly lowering the OAT activity when immobilized in Pd/C. Further stability enhancement is then obtained by switching the nanoparticles from Pd to Rh, which exhibits high reactivity with ClOx(-) intermediates and thus prevents their deactivating reaction with the Re complex. Compared to Re(hoz)2-Pd/C, the new Re(hoz)(htz)-Rh/C catalyst exhibits similar ClO4(-) reduction activity but superior stability, evidenced by a decrease of Re leaching from 37% to 0.25% and stability of surface Re speciation following the treatment of a concentrated "challenge" solution containing 1000 ppm of ClO4(-). This work demonstrates the pivotal roles of coordination chemistry control and tuning of individual catalyst components for achieving both high activity and stability in environmental catalyst applications.

  5. Significant lung volume reduction with endobronchial valves in a patient despite the presence of microcollaterals masked by low-flow Chartis phenotype

    Directory of Open Access Journals (Sweden)

    Yin Y


    Full Text Available Yan Yin,1 Gang Hou,1 Felix J Herth,2 Xiao-bo Wang,1 Qiu-yue Wang,1 Jian Kang1 1Department of Respiratory Medicine, The First Hospital of China Medical University, Shenyang, People’s Republic of China; 2Department of Pneumology and Critical Care Medicine, Thoraxklinik, University of Heidelberg, Heidelberg, Germany Abstract: Satisfactory functional outcomes following bronchoscopic lung volume reduction (BLVR using endobronchial valves (EBVs depend on the absence of collateral ventilation (CV between the target and adjunct lobes. The Chartis system has proven to be useful for determining whether CV is present or absent, but this system can also erroneously indicate the absence of CV, which can lead to BLVR failure. Here, we describe low-flow Chartis phenotype in the target lobe resulted in difficult judgment of existence of CV. Consequently, BLVR with EBVs implanted into the right upper bronchus failed to reduce lung volume or induce atelectasis. Inserting another EBV into the right middle bronchus blocked the latent CV, which led to significant lung volume reduction in the right upper lobe (RUL and right middle lobe (RML and to improve the pulmonary function, 6-min walking distance, and St George respiratory questionnaire scores over a 2-week follow-up period. Low flow in the target lobe is a unique Chartis phenotype and represents the uncertainty of CV, which is a risk factor for the failure of BLVR using EBVs. Clinicians should be aware of this possibility and might be able to resolve the problem by blocking the RUL and RML between which the CV occurs. Keywords: COPD, bronchoscopic lung volume reduction, collateral ventilation, endobronchial valves, Chartis assessment

  6. Esomeprazole use is independently associated with significant reduction of BMD: 1-year prospective comparative safety study of four proton pump inhibitors. (United States)

    Bahtiri, Elton; Islami, Hilmi; Hoxha, Rexhep; Qorraj-Bytyqi, Hasime; Rexhepi, Sylejman; Hoti, Kreshnik; Thaçi, Kujtim; Thaçi, Shpetim; Karakulak, Çağla


    Because of the efficacy of proton pump inhibitors (PPIs), their the use is increasing dramatically. The risk of adverse effects of short-term PPI therapy is low, but there are important safety concerns for potential adverse effects of prolonged PPI therapy. Findings from studies assessing the association between PPI use and bone mineral density (BMD) and/or fracture risk are contradictory. The aim of this study was to prospectively assess potential association of PPI treatment with the 12-month change in BMD of the lumbar spine, femur neck, and total hip. The study was performed in 200 PPI users and 50 PPI nonusers. Lumbar spine (L1-L4), femur neck, and total hip BMD were measured by dual-energy X-ray absorptiometry at the baseline and at 12 months. A total of 209 subjects completed the entire 12 months of the study and were included in the final analysis. A Wilcoxon signed-rank test showed that at 12 months PPI use was associated with statistically significant reductions in femur neck and total hip T scores (Z = -2.764, p = 0.005 and Z = -3.281, p = 0.001, respectively). A multiple linear regression analysis showed that only esomeprazole added significantly to the prediction of total lumbar spine and femur neck T scores (p = 0.048 and p = 0.037, respectively). Compared with the baseline, 12 months of PPI treatment resulted in lower femur neck and total hip BMD T scores. Among the four PPIs studied, esomeprazole was independently associated with significant reduction of BMD, whereas omeprazole had no effects on BMD. Considering the widespread use of PPIs, BMD screening should be considered in the case of prolonged PPI use.

  7. Vibrating minds

    CERN Multimedia


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

  8. Mid-Treatment Sleep Duration Predicts Clinically Significant Knee Osteoarthritis Pain reduction at 6 months: Effects From a Behavioral Sleep Medicine Clinical Trial. (United States)

    Salwen, Jessica K; Smith, Michael T; Finan, Patrick H


    To determine the relative influence of sleep continuity (sleep efficiency, sleep onset latency, total sleep time [TST], and wake after sleep onset) on clinical pain outcomes within a trial of cognitive behavioral therapy for insomnia (CBT-I) for patients with comorbid knee osteoarthritis and insomnia. Secondary analyses were performed on data from 74 patients with comorbid insomnia and knee osteoarthritis who completed a randomized clinical trial of 8-session multicomponent CBT-I versus an active behavioral desensitization control condition (BD), including a 6-month follow-up assessment. Data used herein include daily diaries of sleep parameters, actigraphy data, and self-report questionnaires administered at specific time points. Patients who reported at least 30% improvement in self-reported pain from baseline to 6-month follow-up were considered responders (N = 31). Pain responders and nonresponders did not differ significantly at baseline across any sleep continuity measures. At mid-treatment, only TST predicted pain response via t tests and logistic regression, whereas other measures of sleep continuity were nonsignificant. Recursive partitioning analyses identified a minimum cut-point of 382 min of TST achieved at mid-treatment in order to best predict pain improvements 6-month posttreatment. Actigraphy results followed the same pattern as daily diary-based results. Clinically significant pain reductions in response to both CBT-I and BD were optimally predicted by achieving approximately 6.5 hr sleep duration by mid-treatment. Thus, tailoring interventions to increase TST early in treatment may be an effective strategy to promote long-term pain reductions. More comprehensive research on components of behavioral sleep medicine treatments that contribute to pain response is warranted. © Sleep Research Society 2016. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail

  9. Vibrations on board and health effects

    DEFF Research Database (Denmark)

    Jensen, Anker; Jepsen, Jørgen Riis


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

  10. Theory And Working Of Noise And Vibration

    International Nuclear Information System (INIS)

    Jeong, Il Rok


    This book deals with theory of noise including physical property of noise like term and characteristic of sound, occurrence of sound, characteristic of noise pollution and main cause of occurrence of noise, technique of prevention of noise with noise reduction, construction guide for prevention of noise, and measure of interior noise. It also has the theory of vibration such as an introduction of vibration, and technology of prevention of vibration, official test method of environmental pollution, and summary of protection of the environment.

  11. Cost effectiveness of a screen-and-treat program for asymptomatic vaginal infections in pregnancy: towards a significant reduction in the costs of prematurity. (United States)

    Kiss, H; Pichler, Eva; Petricevic, L; Husslein, P


    The purpose of this investigation was to determine the cost-saving potential of a simple screen-and-treat program for vaginal infection, which has previously been shown to lead to a reduction of 50% in the rate of preterm births. To determine the potential cost savings, we compared the direct costs of preterm delivery of infants with a birth weight below 1900g with the costs of the screen-and-treat program. We used a cut-off birth weight of 1900g because, in our population, all infants with a birth weight below 1900g were transferred to the neonatal intensive care unit. The direct costs associated with preterm delivery were defined to include the costs of the initial hospitalization of both mother and infant and the costs of outpatient follow-up throughout the first 6 years of life of the former preterm infant. The costs of the screen-and-treat program were defined to include the costs of the screening examination and the resulting costs of antimicrobial treatment and follow-up. All calculations were based on health-economic data obtained in the metropolitan area of Vienna, Austria. The number of preterm infants with a birth weight below 1900g was 12 (0.5%) in the intervention group (N=2058) and 29 (1.3%) in the control group (N=2097). The direct costs per preterm birth were found to amount to EUR (euro) 60262. Overall, the expected total savings in direct costs achieved by the screen-and-treat program and the ensuing 50% reduction in the number preterm births with a birth weight below 1900g amounted to more than euro 11 million. The costs of screening and treatment were found to amount to merely 7% of the direct costs saved as a result of the screen-and-treat program. A simple preterm prevention program, consisting of screening and antimicrobial treatment and follow-up of women with asymptomatic vaginal infection, leads not only to a significant reduction in the rate of preterm births but also to substantial savings in the direct costs associated with prematurity.

  12. TH-EF-BRB-03: Significant Cord and Esophagus Dose Reduction by 4π Non-Coplanar Spine Stereotactic Body Radiation Therapy and Stereotactic Radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Yu, V; Tran, A; Nguyen, D; Woods, K; Cao, M; Kaprealian, T; Chin, R; Low, D; Sheng, K [UCLA, Los Angeles, CA (United States)


    Purpose: To demonstrate significant organ-at-risk (OAR) sparing achievable with 4π non-coplanar radiotherapy on spine SBRT and SRS patients. Methods: Twenty-five stereotactic spine cases previously treated with VMAT (n = 23) or IMRT (n = 2) were included in this study. A computer-aided-design model of a Linac with a 3D-scanned human surface was utilized to determine the feasible beam space throughout the 4π steradian and beam specific source-to-target-distances (STD) required for collision avoidance. 4π radiotherapy plans integrating beam orientation and fluence map optimization were then created using a column-generation algorithm. Twenty optimal beams were selected for each case. To evaluate the tradeoff between dosimetric benefit and treatment complexity, 4π plans including only isocentrically deliverable beams were also created. Beam angles of all standard and isocentric 4π plans were imported into Eclipse to recalculate the dose using the same calculation engine as the clinical plans for unbiased comparison. OAR and PTV dose statistics for the clinical, standard-4π, and isocentric-4π plans were compared. Results: Comparing standard-4π to clinical plans, particularly significant average percent reduction in the [mean, maximum] dose of the cord and esophagus of [41%, 21.7%], and [38.7%, 36.4%] was observed, along with global decrease in all other OAR dose statistics. The average cord volume receiving more than 50% prescription dose was substantially decreased by 76%. In addition, improved PTV coverage was demonstrated with a maximum dose reduction of 0.93% and 1.66% increase in homogeneity index (D95/D5). All isocentric-4π plans achieved dosimetric performance equivalent to that of the standard-4π plans with higher delivery complexity. Conclusion: 4π radiotherapy significantly improves stereotactic spine treatment dosimetry. With the substantial OAR dose sparing, PTV dose escalation is considerably safer. Isocentric-4π is sufficient to achieve the

  13. Tritordeum: a novel cereal for food processing with good acceptability and significant reduction in gluten immunogenic peptides in comparison with wheat. (United States)

    Vaquero, Luis; Comino, Isabel; Vivas, Santiago; Rodríguez-Martín, Laura; Giménez, María J; Pastor, Jorge; Sousa, Carolina; Barro, Francisco


    Tritordeum is a novel cereal obtained from the hybridization between durum wheat and a wild barley. This study evaluates acceptance, digestibility and immunotoxic properties of tritordeum, a novel cereal for food processing. Nineteen healthy volunteers participated in a study with different diets to compare tritordeum bread with wheat and gluten-free breads. Tritordeum breads had a similar acceptance to the wheat bread usually consumed, and the acceptance was significantly higher than the gluten-free bread and standardized wheat bread supplied in the study. There was no evidence for gastrointestinal symptoms among volunteers during the study. The reductions in the numbers of immunogenic epitopes in tritordeum in comparison with wheat were 78% for α-gliadins, 57% for γ-gliadins and 93% for ω-gliadins. The analysis of gluten immunogenic peptides (GIP) in stool samples showed a significantly lower excretion in the tritordeum ingestion phase than in the wheat ingestion phase. These results suggest that tritordeum may be an option of interest for general food processing, and especially for those who want to reduce their intake of gluten. However, it is not suitable for celiac disease sufferers as it contains gluten. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. The Significance of Harm Reduction as a Social and Health Care Intervention for Injecting Drug Users: An Exploratory Study of a Needle Exchange Program in Fresno, California. (United States)

    Clarke, Kris; Harris, Debra; Zweifler, John A; Lasher, Marc; Mortimer, Roger B; Hughes, Susan


    Infectious disease remains a significant social and health concern in the United States. Preventing more people from contracting HIV/AIDS or Hepatitis C (HCV), requires a complex understanding of the interconnection between the biomedical and social dimensions of infectious disease. Opiate addiction in the US has skyrocketed in recent years. Preventing more cases of HIV/AIDS and HCV will require dealing with the social determinants of health. Needle exchange programs (NEPs) are based on a harm reduction approach that seeks to minimize the risk of infection and damage to the user and community. This article presents an exploratory small-scale quantitative study of the injection drug using habits of a group of injection drug users (IDUs) at a needle exchange program in Fresno, California. Respondents reported significant decreases in high risk IDU behaviors, including sharing of needles and to a lesser extent re-using of needles. They also reported frequent use of clean paraphernalia. Greater collaboration between social and health outreach professionals at NEPs could provide important frontline assistance to people excluded from mainstream office-based services and enhance efforts to reduce HIV/AIDS or HCV infection.

  15. Significant Artifact Reduction at 1.5T and 3T MRI by the Use of a Cochlear Implant with Removable Magnet: An Experimental Human Cadaver Study. (United States)

    Wagner, Franca; Wimmer, Wilhelm; Leidolt, Lars; Vischer, Mattheus; Weder, Stefan; Wiest, Roland; Mantokoudis, Georgios; Caversaccio, Marco D


    Cochlear implants (CIs) are standard treatment for postlingually deafened individuals and prelingually deafened children. This human cadaver study evaluated diagnostic usefulness, image quality and artifacts in 1.5T and 3T magnetic resonance (MR) brain scans after CI with a removable magnet. Three criteria (diagnostic usefulness, image quality, artifacts) were assessed at 1.5T and 3T in five cadaver heads with CI. The brain magnetic resonance scans were performed with and without the magnet in situ. The criteria were analyzed by two blinded neuroradiologists, with focus on image distortion and limitation of the diagnostic value of the acquired MR images. MR images with the magnet in situ were all compromised by artifacts caused by the CI. After removal of the magnet, MR scans showed an unequivocal artifact reduction with significant improvement of the image quality and diagnostic usefulness, both at 1.5T and 3T. Visibility of the brain stem, cerebellopontine angle, and parieto-occipital lobe ipsilateral to the CI increased significantly after magnet removal. The results indicate the possible advantages for 1.5T and 3T MR scanning of the brain in CI carriers with removable magnets. Our findings support use of CIs with removable magnets, especially in patients with chronic intracranial pathologies.

  16. Consumption of a healthy dietary pattern results in significant reductions in C-reactive protein levels in adults: a meta-analysis. (United States)

    Neale, E P; Batterham, M J; Tapsell, L C


    Consumption of healthy dietary patterns has been associated with reduced risk of cardiovascular disease and metabolic syndrome. Dietary intervention targets disease prevention, so studies increasingly use biomarkers of underlying inflammation and metabolic syndrome progression to examine the diet-health relationship. The extent to which these biomarkers contribute to the body of evidence on healthy dietary patterns is unknown. The aim of this meta-analysis was to determine the effect of healthy dietary patterns on biomarkers associated with adiposity, insulin resistance, and inflammation in adults. A systematic search of Scopus, PubMed, Web of Science, and Cochrane Central Register of Controlled Trials (all years to April 2015) was conducted. Inclusion criteria were randomized controlled trials; effects of dietary patterns assessed on C-reactive protein (CRP), total adiponectin, high-molecular-weight adiponectin, tumor necrosis factor-α, adiponectin:leptin, resistin, or retinol binding protein 4. Random effects meta-analyses were conducted to assess the weighted mean differences in change or final mean values for each outcome. Seventeen studies were included in the review. These reflected research on dietary patterns associated with the Mediterranean diet, Nordic diet, Tibetan diet, and the Dietary Approaches to Stop Hypertension diet. Consumption of a healthy dietary pattern was associated with significant reductions in CRP (weighted mean difference, -0.75 [-1.16, -0.35]; P = .0003). Non-significant changes were found for all other biomarkers. This analysis found evidence for favorable effects of healthy dietary patterns on CRP, with limited evidence for other biomarkers. Future research should include additional randomized controlled trials incorporating a greater range of dietary patterns and biomarkers. Copyright © 2016 Elsevier Inc. All rights reserved.


    Directory of Open Access Journals (Sweden)

    V. K. Sheleh


    Full Text Available The paper considers a process of turning structural steel with asymmetric tool vibrations directed along feeding. Asymmetric vibrations characterized by asymmetry coefficient of vibration cycle, their frequency and amplitude are additionally transferred to the tool in the turning process with the purpose to crush chips. Conditions of stable chip breaking and obtaining optimum dimensions of chip elements have been determined in the paper. In order to reduce a negative impact of the vibration amplitude on a cutting process and quality of the machined surfaces machining must be carried out with its minimum value. In this case certain ratio of the tool vibration frequency to the work-piece rotation speed has been ensured in the paper. A formula has been obtained for calculation of this ratio with due account of the expected length of chip elements and coefficient of vibration cycle asymmetry.Influence of the asymmetric coefficient of the tool vibration cycle on roughness of the machined surfaces and cutting tool wear has been determined in the paper. According to the results pertaining to machining of work-pieces made of 45 and ШХ15 steel the paper presents mathematical relationships of machined surface roughness with cutting modes and asymmetry coefficient of tool vibration cycle. Tool feeding being one of the cutting modes exerts the most significant impact on the roughness value and increase of the tool feeding entails increase in roughness. Reduction in coefficient of vibration cycle asymmetry contributes to surface roughness reduction. However, the cutting tool wear occurs more intensive. Coefficient of the vibration cycle asymmetry must be increased in order to reduce wear rate. Therefore, the choice of the coefficient of the vibration cycle asymmetry is based on the parameters of surface roughness which must be obtained after machining and intensity of tool wear rate.The paper considers a process of turning structural steel with asymmetric

  18. Rotating Liner Engine: Improving Efficiency of Heavy Duty Diesels by Significant Friction Reduction, and Extending the Life of Heavy Duty Engines.

    Energy Technology Data Exchange (ETDEWEB)

    Dardalis, Dimitrios


    This report describes the work on converting a 4 cylinder Cummins ISB engine into a single cylinder Rotating Liner Engine functioning prototype that can be used to measure the friction benefits of rotating the cylinder liner in a high pressure compression ignition engine. A similar baseline engine was also prepared, and preliminary testing was done. Even though the fabrication of the single cylinder prototype was behind schedule due to machine shop delays, the fundamental soundness of the design elements are proven, and the engine has successfully functioned. However, the testing approach of the two engines, as envisioned by the original proposal, proved impossible due to torsional vibration resonance caused by the single active piston. A new approach for proper testing has been proposed,


    Energy Technology Data Exchange (ETDEWEB)

    Noam Lior; Stuart W. Churchill


    the Gordon Conference on Modern Development in Thermodynamics. The results obtained are very encouraging for the development of the RCSC as a commercial burner for significant reduction of NO{sub x} emissions, and highly warrants further study and development.

  20. Experimental chaos in nonlinear vibration isolation system

    International Nuclear Information System (INIS)

    Lou Jingjun; Zhu Shijian; He Lin; He Qiwei


    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.

  1. Selenate reduction to elemental selenium by anaerobic bacteria in sediments and culture: biogeochemical significance of a novel, sulfate-independent respiration (United States)

    Oremland, Ronald S.; Hollibaugh, James T.; Maest, Ann S.; Presser, Theresa S.; Miller, Laurence G.; Culbertson, Charles W.


    Interstitial water profiles of SeO42−, SeO32−, SO42−, and Cl− in anoxic sediments indicated removal of the seleno-oxyanions by a near-surface process unrelated to sulfate reduction. In sediment slurry experiments, a complete reductive removal of SeO42− occurred under anaerobic conditions, was more rapid with H2 or acetate, and was inhibited by O2, NO3−, MnO2, or autoclaving but not by SO42− or FeOOH. Oxidation of acetate in sediments could be coupled to selenate but not to molybdate. Reduction of selenate to elemental selenium was determined to be the mechanism for loss from solution. Selenate reduction was inhibited by tungstate and chromate but not by molybdate. A small quantity of the elemental selenium precipitated into sediments from solution could be resolublized by oxidation with either nitrate or FeOOH, but not with MnO2. A bacterium isolated from estuarine sediments demonstrated selenate-dependent growth on acetate, forming elemental selenium and carbon dioxide as respiratory end products. These results indicate that dissimilatory selenate reduction to elemental selenium is the major sink for selenium oxyanions in anoxic sediments. In addition, they suggest application as a treatment process for removing selenium oxyanions from wastewaters and also offer an explanation for the presence of selenite in oxic waters.

  2. Semi-active control of helicopter vibration using controllable stiffness and damping devices (United States)

    Anusonti-Inthra, Phuriwat

    Semi-active concepts for helicopter vibration reduction are developed and evaluated in this dissertation. Semi-active devices, controllable stiffness devices or controllable orifice dampers, are introduced; (i) in the blade root region (rotor-based concept) and (ii) between the rotor and the fuselage as semi-active isolators (in the non-rotating frame). Corresponding semi-active controllers for helicopter vibration reduction are also developed. The effectiveness of the rotor-based semi-active vibration reduction concept (using stiffness and damping variation) is demonstrated for a 4-bladed hingeless rotor helicopter in moderate- to high-speed forward flight. A sensitivity study shows that the stiffness variation of root element can reduce hub vibrations when proper amplitude and phase are used. Furthermore, the optimal semi-active control scheme can determine the combination of stiffness variations that produce significant vibration reduction in all components of vibratory hub loads simultaneously. It is demonstrated that desired cyclic variations in properties of the blade root region can be practically achieved using discrete controllable stiffness devices and controllable dampers, especially in the flap and lag directions. These discrete controllable devices can produce 35--50% reduction in a composite vibration index representing all components of vibratory hub loads. No detrimental increases are observed in the lower harmonics of blade loads and blade response (which contribute to the dynamic stresses) and controllable device internal loads, when the optimal stiffness and damping variations are introduced. The effectiveness of optimal stiffness and damping variations in reducing hub vibration is retained over a range of cruise speeds and for variations in fundamental rotor properties. The effectiveness of the semi-active isolator is demonstrated for a simplified single degree of freedom system representing the semi-active isolation system. The rotor

  3. Hot Ground Vibration Tests (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...

  4. 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


    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)

  5. Evidence for significantly enhancing reduction of Azo dyes in Escherichia coli by expressed cytoplasmic Azoreductase (AzoA) of Enterococcus faecalis. (United States)

    Feng, J; Heinze, T M; Xu, H; Cerniglia, C E; Chen, H


    Although cytoplasmic azoreductases have been purified and characterized from various bacteria, little evidence demonstrating that these azoreductases are directly involved in azo dye reduction in vivo is known. In order to evaluate the contribution of the enzyme to azo dye reduction in vivo, experiments were conducted to determine the effect of a recombinant cytoplasmic azoreductase (AzoA) from Enterococcus faecalis expressed in Escherichia coli on the rate of metabolism of Methyl Red, Ponceau BS and Orange II. The intact cells that contained IPTG induced AzoA had a higher rate of dye reduction with increases of 2 (Methyl Red), 4 (Ponceau BS) and 2.6 (Orange II)-fold compared to noninduced cells, respectively. Metabolites of Methyl Red isolated from induced cultures were identified as N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid through liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) analyses. In conclusion, our data demonstrate that AzoA from Ent. faecalis is capable of increasing the reduction of azo dyes in intact E. coli cells and that cytoplasmic azoreductase is involved in bacterial dye degradation in vivo.

  6. Theory of vibration protection

    CERN Document Server

    Karnovsky, Igor A


    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...

  7. 256-MDCT for evaluation of urolithiasis: iterative reconstruction allows for a significant reduction of the applied radiation dose while maintaining high subjective and objective image quality

    International Nuclear Information System (INIS)

    Veldhoen, Simon; Laqmani, Azien; Derlin, Thorsten; Karul, Murat; Hammerle, Diego; Adam, Gerhard; Regier, Marc; Buhk, Jan-Hendrick; Sehner, Susanne; Nagel, Hans D.; Chun, Felix


    Multidetector CT (MDCT) is the established imaging modality in diagnostics of urolithiasis. The aim of iterative reconstruction (IR) is to allow for a radiation dose reduction while maintaining high image quality. This study evaluates its performance in MDCT for assessment of urolithiasis. Fifty-two patients underwent non-contrast abdominal MDCT. Twenty-six patients were referred to MDCT under suspicion of urolithiasis, and examined using a dose-reduced scan protocol (RDCT). Twenty-six patients, who had undergone standard-dose MDCT, served as reference for radiation dose comparison. RDCT images were reconstructed using an IR system (iDose4™, Philips Healthcare, Cleveland, OH, USA). Objective image noise (OIN) was recorded and five radiologists rated the subjective image quality independently. Radiation parameters were derived from the scan protocols. The CTDIvol could be reduced by 50% to 5.8 mGy (P < 0.0001). The same reduction was achieved for DLP and effective dose to 253 ± 27 mGy*cm (P < 0.0001) and 3.9 ± 0.4 mSv (P < 0.0001). IR led to a reduction of the OIN of up to 61% compared with classic filtered back projection (FBP) (P < 0.0001). The OIN declined with increasing IR levels. RDCT with FBP showed the lowest scores of subjective image quality (2.32 ± 0.04). Mean scores improved with increasing IR levels. iDose6 was rated with the best mean score (3.66 ± 0.04). The evaluated IR-tool and protocol may be applied to achieve a considerable radiation dose reduction in MDCT for diagnostics of urolithiasis while maintaining a confident image quality. Best image quality, suitable for evaluation of the entire abdomen concerning differential diagnoses, was achieved with iDose6.

  8. Unjamming a granular hopper by vibration (United States)

    Janda, A.; Maza, D.; Garcimartín, A.; Kolb, E.; Lanuza, J.; Clément, E.


    We present an experimental study of the outflow of a hopper continuously vibrated by a piezoelectric device. Outpouring of grains can be achieved for apertures much below the usual jamming limit observed for non-vibrated hoppers. Granular flow persists down to the physical limit of one grain diameter, a limit reached for a finite vibration amplitude. For the smaller orifices, we observe an intermittent regime characterized by alternated periods of flow and blockage. Vibrations do not significantly modify the flow rates both in the continuous and the intermittent regime. The analysis of the statistical features of the flowing regime shows that the flow time significantly increases with the vibration amplitude. However, at low vibration amplitude and small orifice sizes, the jamming time distribution displays an anomalous statistics.

  9. Vibration of machine

    International Nuclear Information System (INIS)

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


    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. Vibrational stability of graphene

    Directory of Open Access Journals (Sweden)

    Yangfan Hu


    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. Quantification of acute vocal fold epithelial surface damage with increasing time and magnitude doses of vibration exposure.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Kojima

    Full Text Available Because the vocal folds undergo repeated trauma during continuous cycles of vibration, the epithelium is routinely susceptible to damage during phonation. Excessive and prolonged vibration exposure is considered a significant predisposing factor in the development of vocal fold pathology. The purpose of the present study was to quantify the extent of epithelial surface damage following increased time and magnitude doses of vibration exposure using an in vivo rabbit phonation model. Forty-five New Zealand white breeder rabbits were randomized to nine groups and received varying phonation time-doses (30, 60, or 120 minutes and magnitude-doses (control, modal intensity phonation, or raised intensity phonation of vibration exposure. Scanning electron microscopy and transmission electron microscopy was used to quantify the degree of epithelial surface damage. Results revealed a significant reduction in microprojection density, microprojection height, and depth of the epithelial surface with increasing time and phonation magnitudes doses, signifying increased epithelial surface damage risk with excessive and prolonged vibration exposure. Destruction to the epithelial cell surface may provide significant insight into the disruption of cell function following prolonged vibration exposure. One important goal achieved in the present study was the quantification of epithelial surface damage using objective imaging criteria. These data provide an important foundation for future studies of long-term tissue recovery from excessive and prolonged vibration exposure.

  12. Enhanced vibration diagnostics using vibration signature analysis

    International Nuclear Information System (INIS)

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


    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)

  13. Stress-first protocol for myocardial perfusion SPECT imaging with semiconductor cameras: high diagnostic performances with significant reduction in patient radiation doses

    International Nuclear Information System (INIS)

    Perrin, Mathieu; Claudin, Marine; Veran, Nicolas; Morel, Olivier; Besseau, Cyril; Boutley, Henri; Djaballah, Wassila; Poussier, Sylvain; Verger, Antoine; Moulin, Frederic; Imbert, Laetitia; Karcher, Gilles; Marie, Pierre-Yves


    Effective doses of 14 mSv or higher are currently being attained in patients having stress and rest myocardial perfusion imaging (MPI) single photon emission computed tomography (SPECT) performed on the same day with conventional protocols. This study aimed to assess the actual reduction in effective doses as well as diagnostic performances for MPI routinely planned with: (1) high-sensitivity cadmium zinc telluride (CZT) cameras, (2) very low injected activities and (3) a stress-first protocol where the normality of stress images may lead to avoiding rest imaging. During a 1-year period, 2,845 patients had MPI on a CZT camera, a single-day stress-first protocol and low injected activities (120 MBq of 99m Tc-sestamibi at stress for 75 kg body weight and threefold higher at rest). The ability to detect > 50 % coronary stenosis was assessed in a subgroup of 149 patients who also had coronary angiography, while the normalcy rate was assessed in a subgroup of 128 patients with a low pretest likelihood of coronary artery disease (<10 %). Overall, 33 % of patients had abnormal MPI of which 34 % were women and 34 % were obese. The mean effective doses and the percentage of exams involving only stress images were: (1) 3.53 ± 2.10 mSv and 37 % in the overall population, (2) 4.83 ± 1.56 mSv and 5 % in the subgroup with angiography and (3) 1.96 ± 1.52 mSv and 71 % in the low-probability subgroup. Sensitivity and global accuracy for identifying the 106 patients with coronary stenosis were 88 and 80 %, respectively, while the normalcy rate was 97 %. When planned with a low-dose stress-first protocol on a CZT camera, MPI provides high diagnostic performances and a dramatic reduction in patient radiation doses. This reduction is even greater in low-risk subgroups with high rates of normal stress images, thus allowing the mean radiation dose to be balanced against cardiac risk in targeted populations. (orig.)

  14. Why do humans have such a prominent nose? The final result of phylogenesis: a significant reduction of the splanchocranium on account of the neurocranium. (United States)

    Mladina, Ranko; Skitarelić, Neven; Vuković, Katarina


    During the last few decades several authors tried to clarify the anthropological aspects of the shape of the human nose and why it has so emphasized projection. Our hypothesis suggests the essentiality of the role of morphologic changes of the human skull which occurred during the phylogenesis. It seems that erectile posture of the man caused remarkable morphological changes of the skull base shape thus being a part of morphologic evolution. The changes in the shape of the human spine from birth to adulthood show a philogenesis in short: a newborn has an almost flat spine like quadrupeds (except in the sacro-coccigeal region), but the spine gets increasingly bent as the person grows (lumbar lordosis, thoracic kyphosis, cervical lordosis). It is well known that the sphenoidal angle was less emphasized in prehistoric man than in modern man. In addition, the cervical spine position in the gorilla, Neanderthal man and modern man is quite different in terms of anterior inclination. Accordingly, there is a great degree of maxillary and mandible reduction in humans. The same differences can be seen when comparing the skull shapes of gorilla, gibbons, Neanderthals and modern man. A major reason for the maxillary and mandible reduction in humans is that their way of feeding has changed remarkably with time. In lower primates and other animals, nasal function, particularly olfaction, may be essential for day-to day survival. In humans, however, this is less important although both impaired nasal breathing and olfaction may affect the function in the other body organs and, of course, influence the quality of life. Nasal configuration in recent humans seems to be associated with the internal nasal cavity wideness and nasal bridge elevation which just happened because of newly developed physiological needs. The skull base angulation leads directly to obvious changes in splanchocranium on the account of neurocranium, since previous is getting "squeezed", by angulation of the

  15. Controlling flexible rotor vibrations using parametric excitation

    Energy Technology Data Exchange (ETDEWEB)

    Atepor, L, E-mail: [Department of Mechanical Engineering, University of Glasgow, G12 8QQ (United Kingdom)


    This paper presents both theoretical and experimental studies of an active vibration controller for vibration in a flexible rotor system. The paper shows that the vibration amplitude can be modified by introducing an axial parametric excitation. The perturbation method of multiple scales is used to solve the equations of motion. The steady-state responses, with and without the parametric excitation terms, is investigated. An experimental test machine uses a piezoelectric exciter mounted on the end of the shaft. The results show a reduction in the rotor response amplitude under principal parametric resonance, and some good correlation between theory and experiment.

  16. Vibration behavior optimization of planetary gear sets

    Directory of Open Access Journals (Sweden)

    Farshad Shakeri Aski


    Full Text Available This paper presents a global optimization method focused on planetary gear vibration reduction by means of tip relief profile modifications. A nonlinear dynamic model is used to study the vibration behavior. In order to investigate the optimal radius and amplitude, Brute Force method optimization is used. One approach in optimization is straightforward and requires considerable computation power: brute force methods try to calculate all possible solutions and decide afterwards which one is the best. Results show the influence of optimal profile on planetary gear vibrations.

  17. [Occupational standing vibration rate and vibrational diseases]. (United States)

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


    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.

  18. Significant sE-Selectin levels reduction after 6 months of anti-TNF-α therapy in non-diabetic patients with moderate-to-severe psoriasis. (United States)

    Genre, Fernanda; Armesto, Susana; Corrales, Alfonso; López-Mejías, Raquel; Remuzgo-Martínez, Sara; Pina, Trinitario; Ubilla, Begoña; Mijares, Verónica; Martín-Varillas, José Luis; Rueda-Gotor, Javier; Portilla, Virginia; Dierssen-Sotos, Trinidad; González-López, Marcos Antonio; González-Vela, María Del Carmen; Blanco, Ricardo; Llorca, Javier; Hernández, José Luis; González-Gay, Miguel Ángel


    Psoriasis patients have high risk of atherosclerosis, characterized by endothelial dysfunction. We aimed to study the association of the endothelial activation biomarkers monocyte chemoattractant protein 1 (MCP-1), soluble (s) E-selectin and P-selectin with disease activity and severity in psoriasis patients treated with anti-TNF-α therapy. Also, to evaluate the relationship of metabolic syndrome features with these biomarkers and the effect of anti-TNF-α therapy on these molecules. Twenty-nine consecutive non-diabetic patients with moderate-to-severe psoriasis who underwent 6 months of anti-TNF-α-adalimumab therapy were studied. Metabolic and clinical evaluation was performed prior to anti-TNF-α treatment (time 0) and 6 months later. MCP-1, sE-selectin and sP-selectin serum levels were determined by ELISA. Dyslipidemic and obese patients showed higher MCP-1 levels at month 6 from the onset of anti-TNF-α therapy (p = .05 and .01, respectively). sE-selectin positively correlated with pro-inflammatory molecules such as asymmetric dimethylarginine, sP-selectin and resistin at baseline and month 6 (p psoriasis. Adalimumab therapy led to a reduction in sE-selectin levels, supporting the beneficial effect of anti-TNF-α therapy on mechanisms associated with the development of atherosclerosis in psoriasis.

  19. Significant reduction of radiation exposure to operator and staff during cardiac interventions by analysis of radiation leakage and improved lead shielding. (United States)

    Kuon, Eberhard; Schmitt, Moritz; Dahm, Johannes B


    The objectives of this study were to disclose and to reduce occupational radiation leakage in invasive cardiology. Prospectively, we analyzed various dose parameters for 330 coronary procedures. We used a Rando phantom to measure scatter entrance skin air kerma to the operator (S-ESAK-O) during fluoroscopy for all standard tube angulations, and to plot isodose lines for 0 degrees /0 degrees -posterior anterior angulation. The patient's measured dose area product due to diagnostic catheterization and elective percutaneous transluminal coronary angioplasty was 6.2 and 10.4 Gycm(2), which represents 11% and 13% of currently typical values, respectively. With use of 0.5- and 1.0-mm overcouch and undercouch shielding, it was possible to reduce the mean of 4,686 nSv/Gycm(2) to 677 and 277 nSv/Gycm(2), respectively. Closure of radiation leakage up to 897 microSv/hour at the operator's gonadal height (80 to 105 cm), not heretofore described, was achieved by an additional 1.0-mm, lead-equivalent undercouch-top and overcouch-flap adjacent to the table, down to a S-ESAK-O/dose area product level of 47.5 nSv/Gycm(2). With use of a 0.5-mm lead apron, collar, glasses, foot-switch shield and 1.0-mm lead cover around the patient's thighs, the operator received a mean S-ESAK-O of 8.5, while his forehead, eyes, thyroid, chest, gonads, and hands were exposed to 68.2, 1.2, 1.2, 1.2, 0.8, and 58.2 nSv/Gycm(2), respectively. In conclusion, radiation-attenuating intervention techniques and improved lead protection can effectively contribute to a new state of the art in invasive cardiology, with reduction of operator radiation exposure to 0.8% of typical S-ESAK-O levels in advanced catheterization laboratories.

  20. Women with provoked vestibulodynia experience clinically significant reductions in pain regardless of treatment: results from a 2-year follow-up study. (United States)

    Davis, Seth N P; Bergeron, Sophie; Binik, Yitzchak M; Lambert, Bernard


    Provoked vestibulodynia (PVD) is a prevalent genital pain syndrome that has been assumed to be chronic, with little spontaneous remission. Despite this assumption, there is a dearth of empirical evidence regarding the progression of PVD in a natural setting. Although many treatments are available, there is no single treatment that has demonstrated efficacy above others. The aims of this secondary analysis of a prospective study were to (i) assess changes over a 2-year period in pain, depressive symptoms, and sexual outcomes in women with PVD; and (ii) examine changes based on treatment(s) type. Participants completed questionnaire packages at Time 1 and a follow-up package 2 years later. Visual analog scale of genital pain, Global Measure of Sexual Satisfaction, Female Sexual Function Index, Beck Depression Inventory, Dyadic Adjustment Scale, and sexual intercourse attempts over the past month. Two hundred thirty-nine women with PVD completed both time one and two questionnaires. For the sample as a whole, there was significant improvement over 2 years on pain ratings, sexual satisfaction, sexual function, and depressive symptoms. The most commonly received treatments were physical therapy, sex/psychotherapy, and medical treatment, although 41.0% did not undergo any treatment. Women receiving no treatment also improved significantly on pain ratings. No single treatment type predicted better outcome for any variable except depressive symptoms, in which women who underwent surgery were more likely to improve. These results suggest that PVD may significantly reduce in severity over time. Participants demonstrated clinically significant pain improvement, even when they did not receive treatment. Furthermore, the only single treatment type predicting better outcomes was surgery, and only for depressive symptoms, accounting for only 2.3% of the variance. These data do not demonstrate the superiority of any one treatment and underscore the need to have control groups in

  1. A novel prediction method of vibration and acoustic radiation for rectangular plate with particle dampers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dongqiang; Wu, Chengjun [Xi' an Jiaotong University, Xi' an (China)


    Particle damping technology is widely used in mechanical and structural systems or civil engineering to reduce vibration and suppress noise as a result of its high efficiency, simplicity and easy implementation, low cost, and energy-saving characteristic without the need for any auxiliary power equipment. Research on particle damping theory has focused on the vibration response of the particle damping structure, but the acoustic radiation of the particle damping structure is rarely investigated. Therefore, a feasible modeling method to predict the vibration response and acoustic radiation of the particle damping structure is desirable to satisfy the actual requirements in industrial practice. In this paper, a novel simulation method based on multiphase flow theory of gas particle by COMSOL multiphysics is developed to study the vibration and acoustic radiation characteristics of a cantilever rectangular plate with Particle dampers (PDs). The frequency response functions and scattered far-field sound pressure level of the plate without and with PDs under forced vibration are predicted, and the predictions agree well with the experimental results. Results demonstrate that the added PDs have a significant effect on vibration damping and noise reduction for the primary structure. The presented work in this paper shows that the theoretical work is valid, which can provide important theoretical guidance for low-noise optimization design of particle damping structure. This model also has an important reference value for the noise control of this kind of structure.

  2. Portable vibration exciter (United States)

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


    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.

  3. From meatless Mondays to meatless Sundays: motivations for meat reduction among vegetarians and semi-vegetarians who mildly or significantly reduce their meat intake. (United States)

    De Backer, Charlotte J S; Hudders, Liselot


    This study explores vegetarians' and semi-vegetarians' motives for reducing their meat intake. Participants are categorized as vegetarians (remove all meat from their diet); semi-vegetarians (significantly reduce meat intake: at least three days a week); or light semi-vegetarians (mildly reduce meat intake: once or twice a week). Most differences appear between vegetarians and both groups of semi-vegetarians. Animal-rights and ecological concerns, together with taste preferences, predict vegetarianism, while an increase in health motives increases the odds of being semi-vegetarian. Even within each group, subgroups with different motives appear, and it is recommended that future researchers pay more attention to these differences.

  4. Resonant vibration control of three-bladed wind turbine rotors

    DEFF Research Database (Denmark)

    Krenk, Steen; Svendsen, Martin Nymann; Høgsberg, Jan Becker


    Rotors with blades, as in wind turbines, are prone to vibrations due to the flexibility of the blades and the support. In the present paper a theory is developed for active control of a combined set of vibration modes in three-bladed rotors. The control system consists of identical collocated...... to influence of other nonresonant modes. The efficiency of the method isdemonstrated byapplication to a rotor with 42 m blades, where the sensor/actuator system is implemented in the form of an axial extensible strut near the root of each blade. The load is provided by a simple but fully threedimensional...... correlated wind velocity field. It is shown by numerical simulations that the active damping system can provide a significant reduction in the response amplitude of the targeted modes, while applying control moments to the blades that are about 1 order of magnitude smaller than the moments from the external...

  5. A significant reduction of ice adhesion on nanostructured surfaces that consist of an array of single-walled carbon nanotubes: A molecular dynamics simulation study (United States)

    Bao, Luyao; Huang, Zhaoyuan; Priezjev, Nikolai V.; Chen, Shaoqiang; Luo, Kai; Hu, Haibao


    It is well recognized that excessive ice accumulation at low-temperature conditions can cause significant damage to civil infrastructure. The passive anti-icing surfaces provide a promising solution to suppress ice nucleation and enhance ice removal. However, despite extensive efforts, it remains a challenge to design anti-icing surfaces with low ice adhesion. Using all-atom molecular dynamics (MD) simulations, we show that surfaces with single-walled carbon nanotube array (CNTA) significantly reduce ice adhesion due to the extremely low solid areal fraction. It was found that the CNTA surface exhibits up to a 45% decrease in the ice adhesion strength in comparison with the atomically smooth graphene surface. The details of the ice detachment from the CNTA surface were examined for different water-carbon interaction energies and temperatures of the ice cube. Remarkably, the results of MD simulations demonstrate that the ice detaching strength depends linearly on the ratio of the ice-surface interaction energy and the ice temperature. These results open the possibility for designing novel robust surfaces with low ice adhesion for passive anti-icing applications.

  6. Combined steam-ultrasound treatment of 2 seconds achieves significant high aerobic count and Enterobacteriaceae reduction on naturally contaminated food boxes, crates, conveyor belts, and meat knives. (United States)

    Musavian, Hanieh S; Butt, Tariq M; Larsen, Annette Baltzer; Krebs, Niels


    Food contact surfaces require rigorous sanitation procedures for decontamination, although these methods very often fail to efficiently clean and disinfect surfaces that are visibly contaminated with food residues and possible biofilms. In this study, the results of a short treatment (1 to 2 s) of combined steam (95°C) and ultrasound (SonoSteam) of industrial fish and meat transportation boxes and live-chicken transportation crates naturally contaminated with food and fecal residues were investigated. Aerobic counts of 5.0 to 6.0 log CFU/24 cm(2) and an Enterobacteriaceae spp. level of 2.0 CFU/24 cm(2) were found on the surfaces prior to the treatment. After 1 s of treatment, the aerobic counts were significantly (P conveyor belts with hinge pins and one type of flat flexible rubber belt, all visibly contaminated with food residues. The aerobic counts of 3.0 to 5.0 CFU/50 cm(2) were significantly (P < 0.05) reduced, while Enterobacteriaceae spp. were reduced to a level below the detection limit. Industrial meat knives were contaminated with aerobic counts of 6.0 log CFU/5 cm(2) on the handle and 5.2 log CFU/14 cm(2) on the steel. The level of Enterobacteriaceae spp. contamination was approximately 2.5 log CFU on the handle and steel. Two seconds of steam-ultrasound treatment reduced the aerobic counts and Enterobacteriaceae spp. to levels below the detection limit on both handle and steel. This study shows that the steam-ultrasound treatment may be an effective replacement for disinfection processes and that it can be used for continuous disinfection at fast process lines. However, the treatment may not be able to replace efficient cleaning processes used to remove high loads of debris.

  7. 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-.

  8. Significant Improvement of Puncture Accuracy and Fluoroscopy Reduction in Percutaneous Transforaminal Endoscopic Discectomy With Novel Lumbar Location System: Preliminary Report of Prospective Hello Study. (United States)

    Fan, Guoxin; Guan, Xiaofei; Zhang, Hailong; Wu, Xinbo; Gu, Xin; Gu, Guangfei; Fan, Yunshan; He, Shisheng


    Prospective nonrandomized control study.The study aimed to investigate the implication of the HE's Lumbar LOcation (HELLO) system in improving the puncture accuracy and reducing fluoroscopy in percutaneous transforaminal endoscopic discectomy (PTED).Percutaneous transforaminal endoscopic discectomy is one of the most popular minimally invasive spine surgeries that heavily depend on repeated fluoroscopy. Increased fluoroscopy will induce higher radiation exposure to surgeons and patients. Accurate puncture in PTED can be achieved by accurate preoperative location and definite trajectory.The HELLO system mainly consists of self-made surface locator and puncture-assisted device. The surface locator was used to identify the exact puncture target and the puncture-assisted device was used to optimize the puncture trajectory. Patients who had single L4/5 or L5/S1 lumbar intervertebral disc herniation and underwent PTED were included the study. Patients receiving the HELLO system were assigned in Group A, and those taking conventional method were assigned in Group B. Study primary endpoint was puncture times and fluoroscopic times, and the secondary endpoint was location time and operation time.A total of 62 patients who received PTED were included in this study. The average age was 45.35 ± 8.70 years in Group A and 46.61 ± 7.84 years in Group B (P = 0.552). There were no significant differences in gender, body mass index, conservative time, and surgical segment between the 2 groups (P > 0.05). The puncture times were 1.19 ± 0.48 in Group A and 6.03 ± 1.87 in Group B (P HELLO system is accurate preoperative location and definite trajectory. This preliminary report indicated that the HELLO system significantly improves the puncture accuracy of PTED and reduces the fluoroscopic times, preoperative location time, as well as operation time. (ChiCTR-ICR-15006730).

  9. The Impact of Traffic-Induced Bridge Vibration on Rapid Repairing High-Performance Concrete for Bridge Deck Pavement Repairs

    Directory of Open Access Journals (Sweden)

    Wei Wang


    Full Text Available Based on forced vibration tests for high-performance concrete (HPC, the influence of bridge vibration induced by traveling vehicle on compressive strength and durability of HPC has been studied. It is concluded that 1 d and 2 d compressive strength of HPC decreased significantly, and the maximum reduction rate is 9.1%, while 28 d compressive strength of HPC had a slight lower with a 3% maximal drop under the action of two simple harmonic vibrations with 2 Hz, 3 mm amplitude, and 4 Hz, 3 mm amplitude. Moreover, the vibration had a slight effect on the compressive strength of HPC when the simple harmonic vibration had 4 Hz and 1 mm amplitude; it is indicated that the amplitude exerts a more prominent influence on the earlier compressive strength with the comparison of the frequency. In addition, the impact of simple harmonic vibration on durability of HPC can be ignored; this shows the self-healing function of concrete resulting from later hydration reaction. Thus, the research achievements mentioned above can contribute to learning the laws by which bridge vibration affects the properties of concrete and provide technical support for the design and construction of the bridge deck pavement maintenance.

  10. Significant reduction in red blood cell transfusions in a general hospital after successful implementation of a restrictive transfusion policy supported by prospective computerized order auditing. (United States)

    Yerrabothala, Swaroopa; Desrosiers, Kevin P; Szczepiorkowski, Zbigniew M; Dunbar, Nancy M


    Our hospital transfusion policy was recently revised to recommend single-unit red blood cell transfusion (RBC TXN) for nonbleeding inpatients when the hemoglobin (Hb) level is not more than 7 g/dL. Our computerized provider order entry system was reconfigured to provide real-time decision support using prospective computerized order auditing based on the most recent Hb level and to remove the single-click ordering option for 2-unit RBC TXNs to enhance compliance. This study was undertaken to assess the impact of these changes on hospital transfusion practice. This study analyzed the total number of transfusion events, proportion of single and 2-unit transfusions and the Hb transfusion trigger in the preimplementation period (October 2011-March 2012) compared to the postimplementation period (October 2012-March 2013). In the postimplementation period the total number of RBC units transfused/1000 patient-days decreased from 60.8 to 44.2 (p auditing has resulted in significantly decreased RBC utilization at our institution. © 2014 AABB.

  11. Diabetes as an independent predictor of left ventricular longitudinal strain reduction at rest and during dobutamine stress test in patients with significant coronary artery disease. (United States)

    Wierzbowska-Drabik, Karina; Trzos, Ewa; Kurpesa, Malgorzata; Rechcinski, Tomasz; Miskowiec, Dawid; Cieslik-Guerra, Urszula; Uznanska-Loch, Barbara; Sobczak, Maria; Kasprzak, Jaroslaw Damian


    Diabetes (DM) is a strong cardiovascular risk factor modifying also the left ventricular (LV) function that may be objectively assessed with echocardiographic strain analysis. Although the impact of isolated DM on myocardial deformation has been already studied, few data concern diabetics with coronary artery disease (CAD), especially in all stages of dobutamine stress echocardiography (DSE). We compared LV systolic function during DSE in CAD with and without DM using state-of-the art speckle-tracking quantification and assessed the impact of DM on LV systolic strain. DSE was performed in 250 patients with angina who afterwards had coronarography with ≥50% stenosis in the left main artery and ≥70% in other arteries considered as significant. In this analysis, we included 127 patients with confirmed CAD: 42 with DM [DM(+); mean age 64 ± 9 years] and 85 patients without DM [DM(-); mean age 63 ± 9 years]. The severity of CAD and LV ejection fraction (EF) were similar in both groups. Global and regional LV peak systolic longitudinal strain (PSLS) revealed in all DSE phases lower values in DM(+) group: 14.5 ± 3.6% vs. 17.4 ± 4.0% at rest; P = 0.0001, 13.8 ± 3.9% vs. 16.7 ± 4.0% at peak stress; P = 0.0002, and 14.2 ± 3.1% vs. 15.5 ± 3.5% at recovery; P = 0.0432 for global parameters, although dobutamine challenge did not enhance further resting differences. LV EF, body surface area, and diabetes were independent predictors for strain in 16-variable model (R2 = 0, 51, P coexisting CAD and DM on myocardial strain. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email:

  12. Spindle vibration and sound field measurement using optical vibrometry


    Tatar, Kourosh


    Mechanical systems often produce a considerable amount of vibration and noise. To be able to obtain a complete picture of the dynamic behaviour of these systems, vibration and sound measurements are of significant importance. Optical metrology is well-suited for non-intrusive measurements on complex objects. The development and the use of remote non-contact vibration measurement methods for spindles are described and vibration measurements on thin- walled structures and sound field measuremen...

  13. Vibration of imperfect rotating disk

    Directory of Open Access Journals (Sweden)

    Půst L.


    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.

  14. Fingers' vibration transmission and grip strength preservation performance of vibration reducing gloves. (United States)

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


    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

  15. Benefits of Spacecraft Level Vibration Testing (United States)

    Gordon, Scott; Kern, Dennis L.


    NASA-HDBK-7008 Spacecraft Level Dynamic Environments Testing discusses the approaches, benefits, dangers, and recommended practices for spacecraft level dynamic environments testing, including vibration testing. This paper discusses in additional detail the benefits and actual experiences of vibration testing spacecraft for NASA Goddard Space Flight Center (GSFC) and Jet Propulsion Laboratory (JPL) flight projects. JPL and GSFC have both similarities and differences in their spacecraft level vibration test approach: JPL uses a random vibration input and a frequency range usually starting at 5 Hz and extending to as high as 250 Hz. GSFC uses a sine sweep vibration input and a frequency range usually starting at 5 Hz and extending only to the limits of the coupled loads analysis (typically 50 to 60 Hz). However, both JPL and GSFC use force limiting to realistically notch spacecraft resonances and response (acceleration) limiting as necessary to protect spacecraft structure and hardware from exceeding design strength capabilities. Despite GSFC and JPL differences in spacecraft level vibration test approaches, both have uncovered a significant number of spacecraft design and workmanship anomalies in vibration tests. This paper will give an overview of JPL and GSFC spacecraft vibration testing approaches and provide a detailed description of spacecraft anomalies revealed.


    Directory of Open Access Journals (Sweden)

    M. Hoseini


    Full Text Available Background: Primary dysmenorrhoea is a common, idiopathic, chronic pelvic pain syndrome, with unknown aetiology which ‎about 50% of women with regular menstrual period suffer. This study was designed to determine the effect of vibration and heat on primary dysmenorrhea. Materials and Methods: In this clinical trial, 75 female students aged 18-22 years old were evaluated for two menstrual cycles. At the first cycle the participants received the routine pain-relief method (synthetic or herbal medicine and traditional remedies. At the second cycle for each participant combined vibration-heat device was applied for ten minutes during ‎menstrual pain. The average of perceived leg pain, lumbar pain and abdominal pain scores at two cycles were determined. The data were analyzed based on Wilcoxon and T tests by using SPSS (v 16.0 for Windows. Results: The average of all perceived pain scores at two cycles were significantly different before pain relief and after both routine methods and using the device (p<0.001. Those were more significantly reduced after using the device in comparison of using routine methods (p<0.001. Conclusion: Since “vibration-heat” is an effective pain relief method, it can be used as a complementary alternative medicine in primary dysmenorrhea reduction.

  17. Bandshapes in vibrational spectroscopy

    International Nuclear Information System (INIS)

    Dijkman, F.G.


    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.)

  18. Transfer vibration through spine


    Benyovszky, Adam


    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...

  19. Vibrational lifetimes of protein amide modes

    International Nuclear Information System (INIS)

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


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

  20. Vibrational entropies in metallic alloys (United States)

    Ozolins, Vidvuds; Asta, Mark; Wolverton, Christopher


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

  1. An Assessment of Using Vibrational Compaction of Calcined HLW and LLW in DWPF Canisters

    International Nuclear Information System (INIS)

    Yi, Yun-Bo; Amme, Robert C.; Shayer, Zeev


    Since 1963, the INEL has calcined almost 8 million gallons of liquid mixed waste and liquid high-level waste, converting it to some 1.1 million gallons of dry calcine (about 4275.0 m3), which consists of alumina-and zirconia-based calcine and zirconia-sodium blend calcine. In addition, if all existing and projected future liquid wastes are solidified, approximately 2,000 m3 of additional calcine will be produced primarily from sodium-bearing waste. Calcine is a more desirable material to store than liquid radioactive waste because it reduces volume, is much less corrosive, less chemically reactive, less mobile under most conditions, easier to monitor and more protective of human health and the environment. This paper describes the technical issue involved in the development of a feasible solution for further volume reduction of calcined nuclear waste for transportation and long term storage, using a standard DWPF canister. This will be accomplished by developing a process wherein the canisters are transported into a vibrational machine, for further volume reduction by about 35%. The random compaction experiments show that this volume reduction is achievable. The main goal of this paper is to demonstrate through computer modeling that it is feasible to use volume reduction vibrational machine without developing stress/strain forces that will weaken the canister integrity. Specifically, the paper presents preliminary results of the stress/strain analysis of the DWPF canister as a function of granular calcined height during the compaction and verifying that the integrity of the canister is not compromised. This preliminary study will lead to the development of better technology for safe compactions of nuclear waste that will have significant economical impact on nuclear waste storage and treatment. The preliminary results will guide us to find better solutions to the following questions: 1) What are the optimum locations and directions (vertical versus horizontal or

  2. Experimental study on titanium wire drawing with ultrasonic vibration. (United States)

    Liu, Shen; Shan, Xiaobiao; Guo, Kai; Yang, Yuancai; Xie, Tao


    Titanium and its alloys have been widely used in aerospace and biomedical industries, however, they are classified as difficult-to-machine materials. In this paper, ultrasonic vibration is imposed on the die to overcome the difficulties during conventional titanium wire drawing processes at the room temperature. Numerical simulations were performed to investigate the variation of axial stress within the contacting region and study the change of the drawing stress with several factors in terms of the longitudinal amplitude and frequency of the applied ultrasonic vibration, the diameter reduction ratio, and the drawing force. An experimental testing equipment was established to measure the drawing torque and rotational velocity of the coiler drum during the wire drawing process. The result indicates the drawing force increases with the growth of the drawing velocity and the reduction ratio, whether with or without vibrations. Application of either form of ultrasonic vibrations contributes to the further decrease of the drawing force, especially the longitudinal vibration with larger amplitude. SEM was employed to detect the surface morphology of the processed wires drawn under the three circumstances. The surface quality of the drawn wires with ultrasonic vibrations was apparently improved compared with those using conventional method. In addition, the longitudinal and torsional composite vibration was more effective for surface quality improvement than pure longitudinal vibration, however, at the cost of weakened drawing force reduction effect. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Influence of treatment by vibration in residual stress generated in the laser welding of HSLA and IF steels

    International Nuclear Information System (INIS)

    Chuvas, T.C.; Fonseca, M.P. Cindra; Castello, D.A.


    The stress relieving treatment by vibration is a new technology under development, which has many advantages over thermal methods. In this work was analyzed the surface residual stress generated in the laser welding of biphasic HSLA and IF steels, both used in the automotive industry. Residual stresses were measured by X-ray diffraction, by the sen 2 Ψ method. Residual stresses generated in the welding of the samples were tensile at all points measured. After welding, the samples were submitted to the mechanical vibration treatment. Some samples presented a significant reduction in the stress values. The welded joints were also characterized by optical microscopy. (author)

  4. Vibration-based monitoring and diagnostics using compressive sensing (United States)

    Ganesan, Vaahini; Das, Tuhin; Rahnavard, Nazanin; Kauffman, Jeffrey L.


    Vibration data from mechanical systems carry important information that is useful for characterization and diagnosis. Standard approaches rely on continually streaming data at a fixed sampling frequency. For applications involving continuous monitoring, such as Structural Health Monitoring (SHM), such approaches result in high volume data and rely on sensors being powered for prolonged durations. Furthermore, for spatial resolution, structures are instrumented with a large array of sensors. This paper shows that both volume of data and number of sensors can be reduced significantly by applying Compressive Sensing (CS) in vibration monitoring applications. The reduction is achieved by using random sampling and capitalizing on the sparsity of vibration signals in the frequency domain. Preliminary experimental results validating CS-based frequency recovery are also provided. By exploiting the sparsity of mode shapes, CS can also enable efficient spatial reconstruction using fewer spatially distributed sensors. CS can thereby reduce the cost and power requirement of sensing as well as streamline data storage and processing in monitoring applications. In well-instrumented structures, CS can enable continued monitoring in case of sensor or computational failures.

  5. Mechanical vibration and shock analysis, sinusoidal vibration

    CERN Document Server

    Lalanne, Christian


    Everything engineers need to know about mechanical vibration and 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

  6. Hydroelastic Vibrations of Ships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Folsø, Rasmus


    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...

  7. Surface vibrational spectroscopy

    International Nuclear Information System (INIS)

    Erskine, J.L.


    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

  8. Gearbox vibration diagnostic analyzer (United States)


    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.

  9. Vibration insensitive interferometry (United States)

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


    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.

  10. Free vibration analysis of corroded steel plates

    Energy Technology Data Exchange (ETDEWEB)

    Eslami-Majd, Alireza; Rahbar-Ranji, Ahmad [AmirKabir University of Technology, Tehran (Iran, Islamic Republic of)


    Vibration analysis of unstiffened/stiffened plates has long been studied due to its importance in the design and condition assessments of ship and offshore structures. Corrosion is inevitable in steel structures and has been so far considered in strength analysis of structures. We studied the free vibration of pitted corroded plates with simply supported boundary conditions. Finite element analysis, with ABAQUS, was used to determine the natural frequencies and mode shapes of corroded plates. Influential parameters including plate aspect ratio, degree of pit, one-sided/both-sided corroded plate, and different corrosion patterns were investigated. By increasing the degree of corrosion, reduction of natural frequency increases. Plate aspect ratio and plate dimensions have no influence on reduction of natural frequency. Different corrosion patterns on the surface of one-sided corroded plates have little influence on reduction of natural frequency. Ratio of pit depth over plate thickness has no influence on the reduction of natural frequency. The reduction of natural frequency in both-sided corroded plates is higher than one-sided corroded plates with the same amount of total corrosion loss. Mode shapes of vibration would change due to corrosion, except square mode shapes.

  11. Silicon micromachined vibrating gyroscopes (United States)

    Voss, Ralf


    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.

  12. System Detects Vibrational Instabilities (United States)

    Bozeman, Richard J., Jr.


    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.

  13. Coherent vibrational dynamics

    CERN Document Server

    Lanzani, Guglielmo; De Silvestri, Sandro


    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.

  14. Frequency adjustable MEMS vibration energy harvester (United States)

    Podder, P.; Constantinou, P.; Amann, A.; Roy, S.


    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.

  15. Frequency adjustable MEMS vibration energy harvester

    International Nuclear Information System (INIS)

    Podder, P; Constantinou, P; Roy, S; Amann, A


    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators. (paper)

  16. PREFACE: Vibrations at surfaces Vibrations at surfaces (United States)

    Rahman, Talat S.


    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

  17. 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...

  18. Improved Laser Vibration Radar

    National Research Council Canada - National Science Library

    Hilaire, Pierre


    .... 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...

  19. NIF Ambient Vibration Measurements

    International Nuclear Information System (INIS)

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


    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

  20. 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.


    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.

  1. Pitavastatin 4 mg Provides Significantly Greater Reduction in Remnant Lipoprotein Cholesterol Compared With Pravastatin 40 mg: Results from the Short-term Phase IV PREVAIL US Trial in Patients With Primary Hyperlipidemia or Mixed Dyslipidemia. (United States)

    Miller, P Elliott; Martin, Seth S; Joshi, Parag H; Jones, Steven R; Massaro, Joseph M; D'Agostino, Ralph B; Sponseller, Craig A; Toth, Peter P


    Remnants are partially hydrolyzed, triglyceride-rich lipoproteins that are implicated in atherosclerosis. We assessed the adequacy of pitavastatin 4 mg and pravastatin 40 mg in reducing atherogenic lipid parameters beyond LDL-C, in particular remnant lipoprotein cholesterol (RLP-C). From the Phase IV, multicenter, randomized, double-blind PREVAIL US (A Study of Pitavastatin 4 mg Vs. Pravastatin 40 mg in Patients With Primary Hyperlipidemia or Mixed Dyslipidemia) trial, we examined lipoprotein cholesterol subfractions using Vertical Auto Profile testing and apolipoproteins B and A-I at baseline and 12 weeks. Participants with primary hyperlipidemia or mixed dyslipidemia had LDL-C levels of 130 to 220 mg/dL and triglyceride levels ≤ 400 mg/dL. In this post hoc analysis, changes in lipid parameters were compared by using ANCOVA. Lipoprotein subfraction data were available in 312 patients (pitavastatin, n = 157; pravastatin, n = 155). Pitavastatin promoted a greater reduction in RLP-C than pravastatin (-13.6 [8.7] vs -9.3 [9.5] mg/dL). Furthermore, the pitavastatin group reported greater reductions in both components of RLP-C (both, P < 0.001): intermediate-density lipoprotein cholesterol (-9.5 [6.3] vs -6.4 [6.6] mg/dL) and very low-density lipoprotein cholesterol subfraction 3 (-4.1 [3.5] vs -2.9 [3.8] mg/dL). There were also greater reductions in the major ratios of risk (apolipoprotein B/apolipoprotein A-I and total cholesterol/HDL-C) (both, P < 0.001). There were no significant changes in HDL-C, its subfractions, or natural log lipoprotein(a)-cholesterol. The mean age was 58.8 ± 8.9 years in the pitavastatin group and 57.0 ± 10.2 years in the pravastatin group. Compared with pravastatin 40 mg daily, pitavastatin 4 mg provided superior reductions in atherogenic lipid parameters beyond LDL-C, including RLP-C. Future studies are needed investigate the clinical implications of lowering directly measured RLP-C as the principal target. identifier

  2. 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....

  3. 2008 Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Philip J. Reid


    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.

  4. Nonlinear Model of Vibrating Screen to Determine Permissible Spring Deterioration for Proper Separation

    Directory of Open Access Journals (Sweden)

    Cristian G. Rodriguez


    Full Text Available Springs of vibrating screens are prone to fatigue induced failure because they operate in a heavy duty environment, with abrasive dust and under heavy cyclic loads. If a spring breaks, the stiffness at supporting positions changes, and therefore the amplitude of motion and the static and dynamic angular inclination of deck motion also change. This change in the amplitude and in the inclination of motion produces a reduction in separation efficiency. Available models are useful to determine motion under nominal operating conditions when angular displacement is not significant. However in practice there is significant angular motion during startup, during shutdown, or under off-design operating conditions. In this article, a two-dimensional three-degree-of-freedom nonlinear model that considers significant angular motion and damping is developed. The proposed model allows the prediction of vibrating screen behavior when there is a reduction in spring stiffness. Making use of this model for an actual vibrating screen in operation in industry has permitted determining a limit for spring’s failure before separation efficiency is affected. This information is of practical value for operation and maintenance staff helping to determine whether or not it is necessary to change springs, and hence optimizing stoppage time.

  5. Blade-Mounted Flap Control for BVI Noise Reduction Proof-of-Concept Test (United States)

    Dawson, Seth; Hassan, Ahmed; Straub, Friedrich; Tadghighi, Hormoz


    This report describes a wind tunnel test of the McDonnell Douglas Helicopter Systems (MDHS) Active Flap Model Rotor at the NASA Langley 14- by 22-Foot Subsonic Tunnel. The test demonstrated that BVI noise reductions and vibration reductions were possible with the use of an active flap. Aerodynamic results supported the acoustic data trends, showing a reduction in the strength of the tip vortex with the deflection of the flap. Acoustic results showed that the flap deployment, depending on the peak deflection angle and azimuthal shift in its deployment schedule, can produce BVI noise reductions as much as 6 dB on the advancing and retreating sides. The noise reduction was accompanied by an increase in low frequency harmonic noise and high frequency broadband noise. A brief assessment of the effect of the flap on vibration showed that significant reductions were possible. The greatest vibration reductions (as much as 76%) were found in the four per rev pitching moment at the hub. Performance improvement cam results were inconclusive, as the improvements were predicted to be smaller than the resolution of the rotor balance.

  6. Experimental Study on the Vibration Control Effect of Long Elastic Sleeper Track in Subways

    Directory of Open Access Journals (Sweden)

    Xiaopei Cai


    Full Text Available The vibration effect of urban rail transit has gained attention from both academia and the industry sector. Long Elastic Sleeper Track (LEST is a new structure for vibration reduction which has recently been designed and applied to Chinese subways. However, little research has been devoted to its vibration reduction effect. In this study, field tests were conducted during peak transit hours on Beijing Subway Line 15 to examine the vibration reduction effects of the common ballastless track and LEST on both straight and curved sections. The results demonstrate that although LEST increases the wheel-rail vertical forces, rail vertical displacements, and rail accelerations to some extent, these effects do not threaten subway operational safety, and vibrations of track bed and tunnel wall are positively mitigated. LEST has an obvious vibration reduction effect at frequencies above 40 Hz. In straight track, the vibration of bottom of the tunnel wall measured in one-third octave bands is reduced by 10.52 dB, while the vibration at point on the tunnel wall at 1.5 m height is reduced by 9.60 dB. For the curved track, the vibrations at those two points are reduced by 9.35 dB and 8.44 dB, respectively. This indicates that LEST reduces vibrations slightly more for the straight track than for the curved track.

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

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, H.


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

  8. The Effects of Vibration and Muscle Fatigue on Trunk Sensorimotor Control in Low Back Pain Patients.

    Directory of Open Access Journals (Sweden)

    Jean-Alexandre Boucher

    Full Text Available Changes in sensorimotor function and increased trunk muscle fatigability have been identified in patients with chronic low back pain (cLBP. This study assessed the control of trunk force production in conditions with and without local erector spinae muscle vibration and evaluated the influence of muscle fatigue on trunk sensorimotor control.Twenty non-specific cLBP patients and 20 healthy participants were asked to perform submaximal isometric trunk extension torque with and without local vibration stimulation, before and after a trunk extensor muscle fatigue protocol. Constant error (CE, variable error (VE as well as absolute error (AE in peak torque were computed and compared across conditions. Trunk extensor muscle activation during isometric contractions and during the fatigue protocol was measured using surface electromyography (sEMG.Force reproduction accuracy of the trunk was significantly lower in the patient group (CE = 9.81 ± 2.23 Nm; AE = 18.16 ± 3.97 Nm than in healthy participants (CE = 4.44 ± 1.68 Nm; AE = 12.23 ± 2.44 Nm. Local erector spinae vibration induced a significant reduction in CE (4.33 ± 2.14 Nm and AE (13.71 ± 3.45 Nm mean scores in the patient group. Healthy participants conversely showed a significant increase in CE (8.17 ± 2.10 Nm and AE (16.29 ± 2.82 Nm mean scores under vibration conditions. The fatigue protocol induced erector spinae muscle fatigue as illustrated by a significant decrease in sEMG median time-frequency slopes. Following the fatigue protocol, patients with cLBP showed significant decrease in sEMG root mean square activity at L4-5 level and responded in similar manner with and without vibration stimulation in regard to CE mean scores.Patients with cLBP have a less accurate force reproduction sense than healthy participants. Local muscle vibration led to significant trunk neuromuscular control improvements in the cLBP patients before and after a muscle fatigue protocol. Muscle vibration

  9. The Effects of Vibration and Muscle Fatigue on Trunk Sensorimotor Control in Low Back Pain Patients (United States)

    Abboud, Jacques; Nougarou, François; Normand, Martin C.


    Introduction Changes in sensorimotor function and increased trunk muscle fatigability have been identified in patients with chronic low back pain (cLBP). This study assessed the control of trunk force production in conditions with and without local erector spinae muscle vibration and evaluated the influence of muscle fatigue on trunk sensorimotor control. Methods Twenty non-specific cLBP patients and 20 healthy participants were asked to perform submaximal isometric trunk extension torque with and without local vibration stimulation, before and after a trunk extensor muscle fatigue protocol. Constant error (CE), variable error (VE) as well as absolute error (AE) in peak torque were computed and compared across conditions. Trunk extensor muscle activation during isometric contractions and during the fatigue protocol was measured using surface electromyography (sEMG). Results Force reproduction accuracy of the trunk was significantly lower in the patient group (CE = 9.81 ± 2.23 Nm; AE = 18.16 ± 3.97 Nm) than in healthy participants (CE = 4.44 ± 1.68 Nm; AE = 12.23 ± 2.44 Nm). Local erector spinae vibration induced a significant reduction in CE (4.33 ± 2.14 Nm) and AE (13.71 ± 3.45 Nm) mean scores in the patient group. Healthy participants conversely showed a significant increase in CE (8.17 ± 2.10 Nm) and AE (16.29 ± 2.82 Nm) mean scores under vibration conditions. The fatigue protocol induced erector spinae muscle fatigue as illustrated by a significant decrease in sEMG median time-frequency slopes. Following the fatigue protocol, patients with cLBP showed significant decrease in sEMG root mean square activity at L4-5 level and responded in similar manner with and without vibration stimulation in regard to CE mean scores. Conclusions Patients with cLBP have a less accurate force reproduction sense than healthy participants. Local muscle vibration led to significant trunk neuromuscular control improvements in the cLBP patients before and after a muscle

  10. Vibration Antiresonance Design for a Spacecraft Multifunctional Structure

    Directory of Open Access Journals (Sweden)

    Dong-Xu Li


    Full Text Available Spacecraft must withstand rigorous mechanical environment experiences such as acceleration, noise, vibration, and shock during the process of launching, satellite-vehicle separation, and so on. In this paper, a new spacecraft multifunctional structure concept designed by us is introduced. The multifunctional structure has the functions of not only load bearing, but also vibration reduction, energy source, thermal control, and so on, and we adopt a series of viscoelastic parts as connections between substructures. Especially in this paper, a vibration antiresonance design method is proposed to realize the vibration reduction. The complex zero-point equations of the vibration system are firstly established, and then the vibration antiresonance design for the system is achieved. For solving the difficulties due to viscoelastic characteristics of the connecting parts, we present the determining formulas to obtain the structural parameters, so that the complex zero-point equations can be satisfied. Numerical simulation and ground experiment demonstrate the correctness and effectiveness of the proposed method. This method can solve the structural vibration control problem under the function constraints of load bearing and energy supplying and will expand the performance of spacecraft functional modules.

  11. Feedforward Control of Gear Mesh Vibration Using Piezoelectric Actuators

    Directory of Open Access Journals (Sweden)

    Gerald T. Montague


    Full Text Available This article presents a novel means for suppressing gear mesh related vibrations. The key components in this approach are piezoelectric actuators and a high-frequency, analog feed forward controller. Test results are presented and show up to a 70% reduction in gear mesh acceleration and vibration control up to 4500 Hz. The principle of the approach is explained by an analysis of a harmonically excited, general linear vibratory system.

  12. Vibration Antiresonance Design for a Spacecraft Multifunctional Structure


    Li, Dong-Xu; Liu, Wang; Hao, Dong


    Spacecraft must withstand rigorous mechanical environment experiences such as acceleration, noise, vibration, and shock during the process of launching, satellite-vehicle separation, and so on. In this paper, a new spacecraft multifunctional structure concept designed by us is introduced. The multifunctional structure has the functions of not only load bearing, but also vibration reduction, energy source, thermal control, and so on, and we adopt a series of viscoelastic parts as connections b...

  13. THz-SAR Vibrating Target Imaging via the Bayesian Method

    Directory of Open Access Journals (Sweden)

    Bin Deng


    Full Text Available Target vibration bears important information for target recognition, and terahertz, due to significant micro-Doppler effects, has strong advantages for remotely sensing vibrations. In this paper, the imaging characteristics of vibrating targets with THz-SAR are at first analyzed. An improved algorithm based on an excellent Bayesian approach, that is, the expansion-compression variance-component (ExCoV method, has been proposed for reconstructing scattering coefficients of vibrating targets, which provides more robust and efficient initialization and overcomes the deficiencies of sidelobes as well as artifacts arising from the traditional correlation method. A real vibration measurement experiment of idle cars was performed to validate the range model. Simulated SAR data of vibrating targets and a tank model in a real background in 220 GHz show good performance at low SNR. Rapidly evolving high-power terahertz devices will offer viable THz-SAR application at a distance of several kilometers.

  14. Nonsynchronous vibrations observed in a supercritical power transmission shaft (United States)

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


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

  15. Particular aspects regarding the effects of whole body vibration exposure

    Directory of Open Access Journals (Sweden)

    Picu Mihaela


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

  16. Vibration transducer calibration techniques (United States)

    Brinkley, D. J.


    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.

  17. Vibration-response due to thickness loss on steel plate excited by resonance frequency (United States)

    Kudus, S. A.; Suzuki, Y.; Matsumura, M.; Sugiura, K.


    The degradation of steel structure due to corrosion is a common problem found especially in the marine structure due to exposure to the harsh marine environment. In order to ensure safety and reliability of marine structure, the damage assessment is an indispensable prerequisite for plan of remedial action on damaged structure. The main goal of this paper is to discuss simple vibration measurement on plated structure to give image on overview condition of the monitored structure. The changes of vibration response when damage was introduced in the plate structure were investigated. The damage on plate was simulated in finite element method as loss of thickness section. The size of damage and depth of loss of thickness were varied for different damage cases. The plate was excited with lower order of resonance frequency in accordance estimate the average remaining thickness based on displacement response obtain in the dynamic analysis. Significant reduction of natural frequency and increasing amplitude of vibration can be observed in the presence of severe damage. The vibration analysis summarized in this study can serve as benchmark and reference for researcher and design engineer.

  18. Lateral vibration behavior analysis and TLD vibration absorption design of the soft yoke single-point mooring system (United States)

    Lyu, Bai-cheng; Wu, Wen-hua; Yao, Wei-an; Du, Yu


    Mooring system is the key equipment of FPSO safe operation. The soft yoke mooring system is regarded as one of the best shallow water mooring strategies and widely applied to the oil exploitation in the Bohai Bay in China and the Gulf of Mexico. Based on the analysis of numerous monitoring data obtained by the prototype monitoring system of one FPSO in the Bohai Bay, the on-site lateral vibration behaviors found on the site of the soft yoke subject to wave load were analyzed. ADAMS simulation and model experiment were utilized to analyze the soft yoke lateral vibration and it was determined that lateral vibration was resonance behaviors caused by wave excitation. On the basis of the soft yoke longitudinal restoring force being guaranteed, a TLD-based vibration damper system was constructed and the vibration reduction experiments with multi-tank space and multi-load conditions were developed. The experimental results demonstrated that the proposed TLD vibration reduction system can effectively reduce lateral vibration of soft yoke structures.

  19. Using frequency response functions to manage image degradation from equipment vibration in the Daniel K. Inouye Solar Telescope (United States)

    McBride, William R.; McBride, Daniel R.


    The Daniel K Inouye Solar Telescope (DKIST) will be the largest solar telescope in the world, providing a significant increase in the resolution of solar data available to the scientific community. Vibration mitigation is critical in long focal-length telescopes such as the Inouye Solar Telescope, especially when adaptive optics are employed to correct for atmospheric seeing. For this reason, a vibration error budget has been implemented. Initially, the FRFs for the various mounting points of ancillary equipment were estimated using the finite element analysis (FEA) of the telescope structures. FEA analysis is well documented and understood; the focus of this paper is on the methods involved in estimating a set of experimental (measured) transfer functions of the as-built telescope structure for the purpose of vibration management. Techniques to measure low-frequency single-input-single-output (SISO) frequency response functions (FRF) between vibration source locations and image motion on the focal plane are described. The measurement equipment includes an instrumented inertial-mass shaker capable of operation down to 4 Hz along with seismic accelerometers. The measurement of vibration at frequencies below 10 Hz with good signal-to-noise ratio (SNR) requires several noise reduction techniques including high-performance windows, noise-averaging, tracking filters, and spectral estimation. These signal-processing techniques are described in detail.

  20. Recovering Intrinsic Fragmental Vibrations Using the Generalized Subsystem Vibrational Analysis. (United States)

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


    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.

  1. Difference between individuals with left and right hemiparesis in the effect of gluteus medius vibration on body weight shifting. (United States)

    Bonan, I; Butet, S; Jamal, K; Yelnik, A; Tasseel Ponche, S; Leplaideur, S


    To test the effect of gluteus medius (GM) vibration on the reduction of asymmetric body weight distribution in individuals with hemiparesis (HP) at two stages of postural recovery. The effects of GM vibration according to the shift of the body weight (%Shift) onto the paretic leg during GM vibration were registered while standing on a force-platform in 40 HP (19 left and 21 right; mean age 54.7±10.6years, mean time after stroke 2.0±1.3months), as soon as they could stand without assistance and 4 to 6 weeks later, and in 40 control subjects (mean age 54.7±10.5years). Without vibration, baseline body weight (BW) distribution was characterized by underloading of the paretic limb (mean BW on the paretic limb 37.2%±13.1%). At the early stage of balance recovery, % shift toward the paretic limb induced by GM vibration differed significantly between left and right HP (P=0.049) and between left HP and controls (C) (P=0.022) and was related to BW asymmetry (r=0.437, P=0.004). Later, GM vibration reduced asymmetric BW distribution in most HP and no difference was found between left and right HP and between left and C. At an advanced stage of postural recovery, GM vibration could help encourage HP to put weight on the affected limb. Interestingly, a behavioral difference was initially observed between right and left HP that could probably be explained by a different strategy due to the baseline severity of the BW asymmetry. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Vibrations in orthopedics. (United States)

    Nokes, L D; Thorne, G C


    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.

  3. Vibration Isolation for Parallel Hydraulic Hybrid Vehicles

    Directory of Open Access Journals (Sweden)

    The M. Nguyen


    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.

  4. Vibrational spectra of aminoacetonitrile

    International Nuclear Information System (INIS)

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


    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)

  5. Vibrations and waves

    CERN Document Server

    Kaliski, S


    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

  6. 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....

  7. Effect of Low Frequency Burner Vibrations on the Characteristics of Jet Diffusion Flames

    Directory of Open Access Journals (Sweden)

    C. Kanthasamy


    Full Text Available Mechanical vibrations introduced in diffusion flame burners significantly affect the flame characteristics. In this experimental study, the effects of axial vibrations on the characteristics of laminar diffusion flames are investigated systematically. The effect of the frequency and amplitude of the vibrations on the flame height oscillations and flame stability is brought out. The amplitude of flame height oscillations is found to increase with increase in both frequency and amplitude of burner vibrations. Vibrations are shown to enhance stability of diffusion flames. Although flame lifts-off sooner with vibrations, stability of the flame increases.

  8. 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


    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.

  9. Vibration in car repair work. (United States)

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


    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.

  10. Effects of aging on vibration detection thresholds at various body regions

    Directory of Open Access Journals (Sweden)

    Walsh Natalie


    Full Text Available Abstract Background The ability to detect sinusoidal vibrations on the skin surface is dependent on the activation of two classes of receptors. The density of such receptors varies across the skin surface and is a factor in determining the sensory acuity of each skin area. However, the acuity of many sensory systems is known to deteriorate with advancing age. The aim of this study was to determine if vibrotactile sensibility of several skin surfaces deteriorated equally with advancing age. Methods Vibration detection thresholds for two frequencies of vibration (30 Hz and 200 Hz were determined using a method of limits protocol, in two groups of healthy adults, one group aged 17 to 27 years and the other aged 55 to 90 years. Sinusoidal vibrations were generated by a computer and delivered to the skin surface via the probe (diameter = 2 mm of a mechanical vibrator. Four skin sites (palmar surface of the tip of the middle finger, volar surface of the forearm, lateral aspect of the shoulder, cheek just caudal to the zygoma were tested. Results The fingertip was the most sensitive site for vibrotactile detection at both frequencies in a substantial majority of subjects. The older group of subjects showed significantly higher detection thresholds for both frequencies at all sites, except the fingertip, when compared to young subjects. Conclusion The study confirms the deterioration of vibrotactile acuity at several skin sites previously reported in the literature. However, there appears to be no significant reduction in vibrotactile detection at the fingertips in older subjects. This may reflect the high receptor density of this area, or the functional importance of vibrotactile sensibility of the fingertips or some combination of both of these factors.

  11. Torsional vibration of crankshaft in an engine propeller nonlinear dynamical system (United States)

    Zhang, X.; Yu, S. D.


    Theoretical and experimental studies on torsional vibration of an aircraft engine-propeller system are presented in this paper. Two system models—a rigid body model and a flexible body model, are developed for predicting torsional vibrations of the crankshaft under different engine powers and propeller pitch settings. In the flexible body model, the distributed torsional flexibility and mass moment of inertia of the crankshaft are considered using the finite element method. The nonlinear autonomous equations of motion for the engine-propeller dynamical system are established using the augmented Lagrange equations, and solved using the Runge-Kutta method after a degrees of freedom reduction scheme is applied. Experiments are carried out on a three-cylinder four-stroke engine. Both theoretical and experimental studies reveal that the crankshaft flexibility has significant influence on the system dynamical behavior.

  12. Evaluating Attenuation of Vibration Response using Particle Impact Damping for a Range of Equipment Assemblies (United States)

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


    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.

  13. Vibration study of the APS magnet support assemblies

    International Nuclear Information System (INIS)

    Wambsganss, M.W.; Jendrzejczyk, J.A.; Chen, S.S.


    Stability of the positron closed orbit is a requirement for successful operation of the Advanced Photon Source. The fact that vibration of the storage ring quadrupole magnets can lead to distortion of the positron closed orbit and to potentially unacceptable beam emittance growth provides the motivation for the subject studies. Low frequency vibrations can be controlled with steering magnets using feedback systems, provided the vibration amplitudes are within the dynamic range of the controllers. High frequency vibration amplitudes, on the other hand, are out of the range of the controller and, therefore must be limited to ensure the emittance growth will not exceed a prescribed value. Vibration criteria were developed based on the requirement that emittance growth be limited to 10 percent. Recognizing that the quadrupole magnets have the most significant effect, three different scenarios were considered: vibration of a single quadrupole within the storage ring, random vibration of all the quadrupoles in the ring, and the hypothetical case of a plane wave sweeping across the site and the quadrupoles following the motion of the plane wave. The maximum allowable peak vibration amplitudes corresponding to these three vibration scenarios are given. The criteria associated with the passage of a plane wave is dependent on wavelength, or, alternatively, on frequency given the wave speed. The wave speed used is that measured as a part of the geotechnical investigation at the APS site

  14. Structural Stability and Vibration

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Pedersen, Pauli

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

  15. Vibrational Spectroscopy and Astrobiology (United States)

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


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

  16. Vibrations and Eigenvalues

    Indian Academy of Sciences (India)

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

  17. Heat exchanger vibration

    International Nuclear Information System (INIS)

    Richards, D.J.W.


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

  18. Man-Induced Vibrations

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Hansen, Lars Pilegaard


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

  19. Heat exchanger vibration

    Energy Technology Data Exchange (ETDEWEB)

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


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

  20. General principles of vibrational spectroscopies

    NARCIS (Netherlands)

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


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

  1. High-Temperature Vibration Damper (United States)

    Clarke, Alan; Litwin, Joel; Krauss, Harold


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

  2. Nanoscale piezoelectric vibration energy harvester design (United States)

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


    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.

  3. Random Vibration Testing of Advanced Wet Tantalum Capacitors (United States)

    Teverovsky, Alexander


    Advanced wet tantalum capacitors allow for improved performance of power supply systems along with substantial reduction of size and weight of the systems that is especially beneficial for space electronics. Due to launch-related stresses, acceptance testing of all space systems includes random vibration test (RVT). However, many types of advanced wet tantalum capacitors cannot pass consistently RVT at conditions specified in MIL-PRF-39006, which impedes their use in space projects. This requires a closer look at the existing requirements, modes and mechanisms of failures, specifics of test conditions, and acceptance criteria. In this work, different lots of advanced wet tantalum capacitors from four manufacturers have been tested at step stress random vibration conditions while their currents were monitored before, during, and after the testing. It has been shown that the robustness of the parts and their reliability are mostly due to effective self-healing processes and limited current spiking or minor scintillations caused by RVT do not increase the risk of failures during operation. A simple model for scintillations events has been used to simulate current spiking during RVT and optimize test conditions. The significance of scintillations and possible effects of gas generation have been discussed and test acceptance criteria for limited current spiking have been suggested.

  4. The effects of vibration-reducing gloves on finger vibration (United States)

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


    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

  5. Influence of foundation type and soil stratification on ground vibration - a parameter study

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard; Prins, Joeri Nithan; Persson, Kent


    a significant influence. Thus, in order to achieve fair accuracy in the prediction of ground vibration caused by sources vibrating on a foundation, accurate models of the ground and foundation may be required. However, for assessment of vibration in the design phase, simple models may be preferred. The paper...

  6. Integrated cable vibration control system using wireless sensors (United States)

    Jeong, Seunghoo; Cho, Soojin; Sim, Sung-Han


    As the number of long-span bridges is increasing worldwide, maintaining their structural integrity and safety become an important issue. Because the stay cable is a critical member in most long-span bridges and vulnerable to wind-induced vibrations, vibration mitigation has been of interest both in academia and practice. While active and semi-active control schemes are known to be quite effective in vibration reduction compared to the passive control, requirements for equipment including data acquisition, control devices, and power supply prevent a widespread adoption in real-world applications. This study develops an integrated system for vibration control of stay-cables using wireless sensors implementing a semi-active control. Arduino, a low-cost single board system, is employed with a MEMS digital accelerometer and a Zigbee wireless communication module to build the wireless sensor. The magneto-rheological (MR) damper is selected as a damping device, controlled by an optimal control algorithm implemented on the Arduino sensing system. The developed integrated system is tested in a laboratory environment using a cable to demonstrate the effectiveness of the proposed system on vibration reduction. The proposed system is shown to reduce the vibration of stay-cables with low operating power effectively.

  7. Resonant vibration control of wind turbine blades

    DEFF Research Database (Denmark)

    Svendsen, Martin Nymann; Krenk, Steen; Høgsberg, Jan Becker


    . 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. Approaches for reducing structural vibration of the carbody railway vehicles

    Directory of Open Access Journals (Sweden)

    Dumitriu Mădălina


    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.

  9. Vibration of fuel bundles

    International Nuclear Information System (INIS)

    Chen, S.S.


    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

  10. Noise and vibration improvement technologies for engines; Engine ni okeru soon shindo kaizen gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Kuzuoka, H.; Maeda, R. [Nissan Motor Co. Ltd., Tokyo (Japan)


    This is an outline of recent measurement and simulation technology for reduction of engine noise and vibration. We can recognize correct phenomenon by visualization of noise and vibration phenomena using new measurement technology. And we can create optimum countermeasures using new simulation technology In this report, examples of application of these technology in the development of NEO-DI engines are provided. (author)

  11. Pickin’ up good vibrations

    CERN Multimedia

    Katarina Anthony


    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...

  12. CaSO4 Scale Formation on Vibrated Piping System in the Presence Citric Acid (United States)

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


    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.

  13. Finite Element Analysis and Experimental Study on Elbow Vibration Transmission Characteristics (United States)

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


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


    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [ORNL


    Since the operation of PS09 SR module in 2007, it has been observed that there is vibration in various parts of the structures, on various segments of piping, and on appurtenance items. At DOT Pipeline and Hazardous Materials Safety Administration (PHMSA) request, ORNL Subject Matter Experts support PHMSA in its review and analysis of the observed vibration phenomenon. The review and analysis consider possible effects of pipeline design features, vibration characteristics, machinery configuration, and operating practices on the structural capacity and leak tight integrity of the pipeline. Emphasis is placed on protection of welded joints and machinery against failure from cyclic loading. A series of vibration measurements were carried out by the author during the site visit to PS09, the power of the operating pump during the data collection is at about 2970KW, which is less than that of APSC's vibration data collected at 3900KW. Thus, a first order proportional factor of 4900/2970 was used to project the measured velocity data to that of APSC's measurement of the velocity data. It is also noted here that the average or the peak-hold value of the measured velocity data was used in the author's reported data, and only the maximum peak-hold data was used in APSC's reported data. Therefore, in some cases APSC's data is higher than the author's projective estimates that using the average data. In general the projected velocity data are consistent with APSC's measurements; the examples of comparison at various locations are illustrated in the Table 1. This exercise validates and confirms the report vibration data stated in APSC's summary report. After the reinforcement project for PS09 Station, a significant reduction of vibration intensity was observed for the associated pipelines at the SR Modules. EDI Co. provided a detailed vibration intensity investigation for the newly reinforced Pump Module structures and the associated

  15. Comparison of Annoyance from Railway Noise and Railway Vibration. (United States)

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


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

  16. Structural Characteristics of Rotate Vector Reducer Free Vibration

    Directory of Open Access Journals (Sweden)

    Chuan Chen


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

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

    International Nuclear Information System (INIS)

    Hara, Fumio


    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.)

  18. Development of an innovative device for ultrasonic elliptical vibration cutting. (United States)

    Zhou, Ming; Hu, Linhua


    An innovative ultrasonic elliptical vibration cutting (UEVC) device with 1st resonant mode of longitudinal vibration and 3rd resonant mode of bending vibration was proposed in this paper, which can deliver higher output power compared to previous UEVC devices. Using finite element method (FEM), resonance frequencies of the longitudinal and bending vibrations were tuned to be as close as possible in order to excite these two vibrations using two-phase driving voltages at a single frequency, while wave nodes of the longitudinal and bending vibrations were also adjusted to be as coincident as possible for mounting the device at a single fixed point. Based on the simulation analysis results a prototype device was fabricated, then its vibration characteristics were evaluated by an impedance analyzer and a laser displacement sensor. With two-phase sinusoidal driving voltages both of 480 V(p-p) at an ultrasonic frequency of 20.1 kHz, the developed prototype device achieved an elliptical vibration with a longitudinal amplitude of 8.9 μm and a bending amplitude of 11.3 μm. The performance of the developed UEVC device is assessed by the cutting tests of hardened steel using single crystal diamond tools. Experimental results indicate that compared to ordinary cutting process, the tool wear is reduced significantly by using the proposed device. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Computational Fluid Dynamic Analysis of a Vibrating Turbine Blade

    Directory of Open Access Journals (Sweden)

    Osama N. Alshroof


    Full Text Available This study presents the numerical fluid-structure interaction (FSI modelling of a vibrating turbine blade using the commercial software ANSYS-12.1. The study has two major aims: (i discussion of the current state of the art of modelling FSI in gas turbine engines and (ii development of a “tuned” one-way FSI model of a vibrating turbine blade to investigate the correlation between the pressure at the turbine casing surface and the vibrating blade motion. Firstly, the feasibility of the complete FSI coupled two-way, three-dimensional modelling of a turbine blade undergoing vibration using current commercial software is discussed. Various modelling simplifications, which reduce the full coupling between the fluid and structural domains, are then presented. The one-way FSI model of the vibrating turbine blade is introduced, which has the computational efficiency of a moving boundary CFD model. This one-way FSI model includes the corrected motion of the vibrating turbine blade under given engine flow conditions. This one-way FSI model is used to interrogate the pressure around a vibrating gas turbine blade. The results obtained show that the pressure distribution at the casing surface does not differ significantly, in its general form, from the pressure at the vibrating rotor blade tip.

  20. Vibration noise control in laser satellite communication (United States)

    Saksonov, Avigdor; Shlomi, Arnon; Kopeika, Norman S.


    Laser satellite communication has become especially attractive in recent years. Because the laser beam width is narrow than in the RF or microwave range, the transmitted optical power may be significantly reduced. This leads to development of miniature communication systems with extremely low power consumption. On the other hand, the laser communication channel is very sensitive to vibrations of the optical platform. These vibrations cause angular noise in laser beam pointing, comparable to the laser beam width. As result, as significant portion of the optical power between transmitter and receiver is lost and the bit error rate is increased. Consequently, vibration noise control is a critical problem in laser satellite communication. The direction of the laser beam is corrected with a fast steering mirror (FSM). In this paper are presented two approaches for the FSM control. One is the feedback control that uses an LQG algorithm. The second is the direct feed- forward control when vibration noise is measured by three orthogonal accelerometers and drives directly the F SM. The performances of each approach are evaluated using MATLAB simulations.

  1. Vibration-induced particle formation during yogurt fermentation - Industrial vibration measurements and development of an experimental setup. (United States)

    Körzendörfer, Adrian; Temme, Philipp; Nöbel, Stefan; Schlücker, Eberhard; Hinrichs, Jörg


    The aim of the study was to investigate the effects of vibrations during yogurt fermentation. Machinery such as pumps and switching valves generate vibrations that may disturb the gelation by inducing large particles. Oscillation measurements on an industrial yogurt production line showed that oscillations are transferred from pumps right up to the fermentation tanks. An experimental setup (20L) was developed to study the effect of vibrations systematically. The fermenters were decoupled with air springs to enable reference fermentations under idle conditions. A vibration exciter was used to stimulate the fermenters. Frequency sweeps (25-1005Hz, periodic time 10s) for 20min from pH5.4 induced large particles. The number of visible particles was significantly increased from 35±4 (reference) to 89±9 particles per 100g yogurt. Rheological parameters of the stirred yogurt samples were not influenced by vibrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Random vibrations theory and practice

    CERN Document Server

    Wirsching, Paul H; Ortiz, Keith


    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...


    Directory of Open Access Journals (Sweden)

    Smirnov Vladimir Alexandrovich


    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.

  4. Vibration damping method and apparatus (United States)

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


    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.

  5. Atomic beams probe surface vibrations

    International Nuclear Information System (INIS)

    Robinson, A.L.


    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)

  6. Using periodicity to mitigate ground vibration

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard


    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...

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

    Directory of Open Access Journals (Sweden)

    Claudia Celletti


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

  8. Digital analysis of vibrations

    International Nuclear Information System (INIS)

    Bohnstedt, H.J.; Walter, G.


    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

  9. Turbine blade vibration dampening (United States)

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


    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.

  10. Lattice Vibrations in Chlorobenzenes:

    DEFF Research Database (Denmark)

    Reynolds, P. A.; Kjems, Jørgen; White, J. W.


    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...

  11. Vibration control, machine diagnostics

    International Nuclear Information System (INIS)


    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

  12. Wireless Inductive Power Device Suppresses Blade Vibrations (United States)

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


    possible to moderate vibration on or in turbomachinery blades by providing 100 W of wireless electrical power and actuation control to thin, lightweight vibration-suppressing piezoelectric patches (eight actuation and eight sensor patches in this prototype, for a total of 16 channels) positioned strategically on the surface of, or within, titanium fan blades, or embedded in composite fan blades. This approach moves significantly closer to the ultimate integration of "active" vibration suppression technology into jet engines and other turbomachinery devices such as turbine electrical generators used in the power industry. The novel feature of this device is in its utilization of wireless technology to simultaneously sense and actively control vibration in rotating or stationary turbomachinery blades using piezoelectric patches. In the past, wireless technology was used solely for sensing and diagnostics. This technology, however, will accomplish much more, in terms of simultaneously sensing, suppressing blade vibration, and making it possible for detailed study of vibration impact in turbomachinery blades.

  13. 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

  14. Nonlinear convergence active vibration absorber for single and multiple frequency vibration control (United States)

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


    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.

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

    International Nuclear Information System (INIS)

    Maxwell, H.


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

  16. Equilibrium structure and atomic vibrations of Nin clusters (United States)

    Borisova, Svetlana D.; Rusina, Galina G.


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

  17. Effects of whole body vibration on motor unit recruitment and threshold. (United States)

    Pollock, Ross D; Woledge, Roger C; Martin, Finbarr C; Newham, Di J


    Whole body vibration (WBV) has been suggested to elicit reflex muscle contractions but this has never been verified. We recorded from 32 single motor units (MU) in the vastus lateralis of 7 healthy subjects (34 ± 15.4 yr) during five 1-min bouts of WBV (30 Hz, 3 mm peak to peak), and the vibration waveform was also recorded. Recruitment thresholds were recorded from 38 MUs before and after WBV. The phase angle distribution of all MUs during WBV was nonuniform (P recruitment threshold after WBV and average recruitment threshold; the lowest threshold MUs increased recruitment threshold (P = 0.008) while reductions were observed in the higher threshold units (P = 0.031). We investigated one possible cause of changed thresholds. Presynaptic inhibition in the soleus was measured in 8 healthy subjects (29 ± 4.6 yr). A total of 30 H-reflexes (stimulation intensity 30% Mmax) were recorded before and after WBV: 15 conditioned by prior stimulation (60 ms) of the antagonist and 15 unconditioned. There were no significant changes in the relationship between the conditioned and unconditioned responses. The consistent phase angle at which each MU fired during WBV indicates the presence of reflex muscle activity similar to the tonic vibration reflex. The varying response in high- and low-threshold MUs may be due to the different contributions of the mono- and polysynaptic pathways but not presynaptic inhibition.

  18. Simulation Study of Electronic Damping of Microphonic Vibrations in Superconducting Cavities

    International Nuclear Information System (INIS)

    Alicia Hofler; Jean Delayen


    Electronic damping of microphonic vibrations in superconducting rf cavities involves an active modulation of the cavity field amplitude in order to induce ponderomotive forces that counteract the effect of ambient vibrations on the cavity frequency. In lightly beam loaded cavities, a reduction of the microphonics-induced frequency excursions leads directly to a reduction of the rf power required for phase and amplitude stabilization. Jefferson Lab is investigating such an electronic damping scheme that could be applied to the JLab 12 GeV upgrade, the RIA driver, and possibly to energy-recovering superconducting linacs. This paper discusses a model and presents simulation results for electronic damping of microphonic vibrations

  19. Changes in the vibration sensitivity and pressure pain thresholds in patients with burning mouth syndrome (United States)

    Ferreira, Natália dos Reis; Janini, Maria Elisa Rangel


    Objective To investigate the presence of changes in vibration detection and pressure pain threshold in patients with burning-mouth syndrome (BMS). Design of the study Case-control study. The sample was composed of 30 volunteers, 15 with BMS and 15 in the control group. The pressure-pain threshold (PPT) and vibration-detection threshold (VDT) were examined. The clinical evaluation was complemented with the McGill Pain Questionnaire (MPQ), Douleur Neuropathique 4 (DN4) and Beck Depression and Anxiety Inventories (BDI and BAI, respectively). Results BMS subjects showed a statistically significant higher PPT in the tongue (p = 0.002), right (p = 0.001) and left (p = 0.004) face, and a significant reduction of the VDT in the tongue (p = 0.013) and right face (p = 0.030). Significant differences were also found when comparing the PPT and the VDT of distinct anatomical areas. However, a significant interaction (group × location) was only for the PPT. BMS subjects also showed significantly higher levels of depression (p = 0.01), as measured by the BDI, compared to controls; and a significant inverse correlation between the VDT in the left face and anxiety levels was detected. Conclusions The study of somatosensory changes in BMS and its correlations with the clinical features as well as the levels of anxiety and depression expands current understanding of the neuropathic origin and the possible contribution of psychogenic factors related to this disease. PMID:29782537

  20. Changes in the vibration sensitivity and pressure pain thresholds in patients with burning mouth syndrome.

    Directory of Open Access Journals (Sweden)

    Brenda de Souza Moura

    Full Text Available To investigate the presence of changes in vibration detection and pressure pain threshold in patients with burning-mouth syndrome (BMS.Case-control study. The sample was composed of 30 volunteers, 15 with BMS and 15 in the control group. The pressure-pain threshold (PPT and vibration-detection threshold (VDT were examined. The clinical evaluation was complemented with the McGill Pain Questionnaire (MPQ, Douleur Neuropathique 4 (DN4 and Beck Depression and Anxiety Inventories (BDI and BAI, respectively.BMS subjects showed a statistically significant higher PPT in the tongue (p = 0.002, right (p = 0.001 and left (p = 0.004 face, and a significant reduction of the VDT in the tongue (p = 0.013 and right face (p = 0.030. Significant differences were also found when comparing the PPT and the VDT of distinct anatomical areas. However, a significant interaction (group × location was only for the PPT. BMS subjects also showed significantly higher levels of depression (p = 0.01, as measured by the BDI, compared to controls; and a significant inverse correlation between the VDT in the left face and anxiety levels was detected.The study of somatosensory changes in BMS and its correlations with the clinical features as well as the levels of anxiety and depression expands current understanding of the neuropathic origin and the possible contribution of psychogenic factors related to this disease.

  1. Vibrational spectra of ordered perovskites

    NARCIS (Netherlands)

    Corsmit, A.F.; Hoefdraad, H.E.; Blasse, G.


    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.

  2. 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....

  3. Low Cost Digital Vibration Meter. (United States)

    Payne, W Vance; Geist, Jon


    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.

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

    Directory of Open Access Journals (Sweden)

    Felix Weber


    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.

  5. Prototype observation and influencing factors of environmental vibration induced by flood discharge

    Directory of Open Access Journals (Sweden)

    Xin Wang


    Full Text Available Due to a wide range of field vibration problems caused by flood discharge at the Xiangjiaba Hydropower Station, vibration characteristics and influencing factors were investigated based on prototype observation. The results indicate that field vibrations caused by flood discharge have distinctive characteristics of constancy, low frequency, small amplitude, and randomness with impact, which significantly differ from the common high-frequency vibration characteristics. Field vibrations have a main frequency of about 0.5–3.0 Hz and the characteristics of long propagation distance and large-scale impact. The vibration of a stilling basin slab runs mainly in the vertical direction. The vibration response of the guide wall perpendicular to the flow is significantly stronger than it is in other directions and decreases linearly downstream along the guide wall. The vibration response of the underground turbine floor is mainly caused by the load of unit operation. Urban environmental vibration has particular distribution characteristics and change patterns, and is greatly affected by discharge, scheduling modes, and geological conditions. Along with the increase of the height of residential buildings, vibration responses show a significant amplification effect. The horizontal and vertical vibrations of the 7th floor are, respectively, about 6 times and 1.5 times stronger than the corresponding vibrations of the 1st floor. The vibration of a large-scale chemical plant presents the combined action of flood discharge and working machines. Meanwhile, it is very difficult to reduce the low-frequency environmental vibrations. Optimization of the discharge scheduling mode is one of the effective measures of reducing the flow impact loads at present. Choosing reasonable dam sites is crucial.

  6. Reducing vibration transfer from power plants by active methods (United States)

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


    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

  7. Theory for Nonlinear Spectroscopy of Vibrational Polaritons


    Ribeiro, RF; Dunkelberger, AD; Xiang, B; Xiong, W; Simpkins, BS; Owrutsky, JC; Yuen-Zhou, J


    Molecular polaritons have gained considerable attention due to their potential to control nanoscale molecular processes by harnessing electromagnetic coherence. Although recent experiments with liquid-phase vibrational polaritons have shown great promise for exploiting these effects, significant challenges remain in interpreting their spectroscopic signatures. In this letter, we develop a quantum-mechanical theory of pump-probe spectroscopy for this class of polaritons based on the quantum La...

  8. Piezoelectric pushers for active vibration control of rotating machinery (United States)

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


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

  9. Research on vibration signal analysis and extraction method of gear local fault (United States)

    Yang, X. F.; Wang, D.; Ma, J. F.; Shao, W.


    Gear is the main connection parts and power transmission parts in the mechanical equipment. If the fault occurs, it directly affects the running state of the whole machine and even endangers the personal safety. So it has important theoretical significance and practical value to study on the extraction of the gear fault signal and fault diagnosis of the gear. In this paper, the gear local fault as the research object, set up the vibration model of gear fault vibration mechanism, derive the vibration mechanism of the gear local fault and analyzes the similarities and differences of the vibration signal between the gear non fault and the gears local faults. In the MATLAB environment, the wavelet transform algorithm is used to denoise the fault signal. Hilbert transform is used to demodulate the fault vibration signal. The results show that the method can denoise the strong noise mechanical vibration signal and extract the local fault feature information from the fault vibration signal..

  10. Electronic energy transfer through non-adiabatic vibrational-electronic resonance. II. 1D spectra for a dimer (United States)

    Tiwari, Vivek; Jonas, David M.


    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. Lattice vibration spectra. 16

    International Nuclear Information System (INIS)

    Lutz, H.D.; Willich, P.


    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)

  12. Partial admission effect on the performance and vibration of a supersonic impulse turbine (United States)

    Lee, Hang Gi; Shin, Ju Hyun; Choi, Chang-Ho; Jeong, Eunhwan; Kwon, Sejin


    This study experimentally investigates the effects of partial admission on the performance and vibration outcomes of a supersonic impulse turbine with circular nozzles. The turbine of a turbopump for a gas-generator-type liquid rocket engine in the Korea Space Launch Vehicle-II is of the supersonic impulse type with the partial admission configuration for obtaining a high specific power. Partial admission turbines with a low-flow-rate working gas exhibit benefits over turbines with full admission, such as loss reduction, ease of controllability of the turbine power output, and simple turbine configurations with separate starting sections. However, the radial force of the turbine rotor due to the partial admission causes an increase in turbine vibration. Few experimental studies have previously been conducted regarding the partial admission effects on supersonic impulse turbines with circular nozzles. In the present study, performance tests of supersonic impulse turbines with circular nozzles were conducted for various partial admission ratios using a turbine test facility with high-pressure air in order to investigate the resulting aerodynamic performance and vibration. Four types of turbines with partial admission ratios of 0.17, 0.42, 0.75 and 0.83 were tested. Results show that the efficiencies at the design point increase linearly as the partial admission ratios increase. Moreover, as the velocity ratios increase, the difference in efficiency from the reference turbine with a partial admission ratio of 0.83 becomes increasingly significant, and the magnitudes of these differences are proportional to the square of the velocity ratios. Likewise, the decrease in the partial admission ratio results in an increase in the turbine vibration level owing to the increase in the radial force.

  13. Study on the separation effect of high-speed ultrasonic vibration cutting. (United States)

    Zhang, Xiangyu; Sui, He; Zhang, Deyuan; Jiang, Xinggang


    High-speed ultrasonic vibration cutting (HUVC) has been proven to be significantly effective when turning Ti-6Al-4V alloy in recent researches. Despite of breaking through the cutting speed restriction of the ultrasonic vibration cutting (UVC) method, HUVC can also achieve the reduction of cutting force and the improvements in surface quality and cutting efficiency in the high-speed machining field. These benefits all result from the separation effect that occurs during the HUVC process. Despite the fact that the influences of vibration and cutting parameters have been discussed in previous researches, the separation analysis of HUVC should be conducted in detail in real cutting situations, and the tool geometry parameters should also be considered. In this paper, three situations are investigated in details: (1) cutting without negative transient clearance angle and without tool wear, (2) cutting with negative transient clearance angle and without tool wear, and (3) cutting with tool wear. And then, complete separation state, partial separation state and continuous cutting state are deduced according to real cutting processes. All the analysis about the above situations demonstrate that the tool-workpiece separation will take place only if appropriate cutting parameters, vibration parameters, and tool geometry parameters are set up. The best separation effect was obtained with a low feedrate and a phase shift approaching 180 degrees. Moreover, flank face interference resulted from the negative transient clearance angle and tool wear contributes to an improved separation effect that makes the workpiece and tool separate even at zero phase shift. Finally, axial and radial transient cutting force are firstly obtained to verify the separation effect of HUVC, and the cutting chips are collected to weigh the influence of flank face interference. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. The vibrational signals that male fiddler crabs ( Uca lactea) use to attract females into their burrows (United States)

    Takeshita, Fumio; Murai, Minoru


    In some fiddler crab species, males emit vibrations from their burrows to mate-searching females after they have attracted a female to the burrow entrance using a waving display. Although the vibrations are considered acoustic signals to induce mating, it has not been demonstrated whether the vibrations attract the females into the burrow and, consequently, influence females' mating decisions. We investigated the structures and patterns of the vibrations using a dummy female and demonstrated experimentally a female preference for male vibrations in Uca lactea in the field. The acoustic signals consisted of repetitions of pulses. The dominant frequency of the pulses decreased with male carapace width. The pulse length decreased slightly with an increasing number of vibrational repetitions, and the pulse interval increased with increasing repetitions. These factors imply that the vibrations convey information on male characteristics, such as body size and stamina. In the experiment on female mate choice, the females significantly preferred males with higher pulse repetition rates when they were positioned at the entrance of the burrow, indicating that the females use the male vibrational signals to decide whether to enter the burrow. However, females showed no preference for the vibrations once they were inside a burrow, i.e., whether they decided to copulate, suggesting that the vibrations do not independently affect a female's final decision of mate choice. The vibrations inside the burrow might influence a female's decision by interaction with other male traits such as the burrow structure.

  15. The effect of mechanical vibration on orthodontically induced root resorption. (United States)

    Yadav, Sumit; Dobie, Thomas; Assefnia, Amir; Kalajzic, Zana; Nanda, Ravindra


    To investigate the effect of low-frequency mechanical vibration (LFMV) on orthodontically induced root resorption. Forty male CD1, 12-week-old mice were used for the study. The mice were randomly divided into five groups: group 1 (baseline)-no spring and no mechanical vibration, group 2-orthodontic spring but no vibration, group 3-orthodontic spring and 5 Hz of vibration applied to the maxillary first molar, group 4-orthodontic spring and 10 Hz of vibration applied to maxillary first molar, and group 5-orthodontic spring and 20 Hz of vibration applied to maxillary first molar. In the different experimental groups, the first molar was moved mesially for 2 weeks using a nickel-titanium coil spring delivering 10 g of force. LFMVs were applied at 5 Hz, 10 Hz, and 20 Hz. Microfocus X-ray computed tomography imaging was used to analyze root resorption. Additionally, to understand the mechanism, we applied LFMV to MC3T3 cells, and gene expression analyses were done for receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG). Orthodontic tooth movement leads to decreased root volume (increased root resorption craters). Our in vivo experiments showed a trend toward increase in root volume with different frequencies of mechanical vibration. In vitro gene expression analyses showed that with 20 Hz of mechanical vibration, there was a significant decrease in RANKL and a significant increase in OPG expression. There was a trend toward decreased root resorption with different LFMVs (5 Hz, 10 Hz, and 20 Hz); however, it was not more statistically significant than the orthodontic-spring-only group.

  16. Vibrational Spectroscopy of Ionic Liquids. (United States)

    Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C


    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.

  17. Electromagnetic harvester for lateral vibration in rotating machines (United States)

    de Araujo, Marcus Vinícius Vitoratti; Nicoletti, Rodrigo


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

  18. Molecular vibrations the theory of infrared and Raman vibrational spectra

    CERN Document Server

    Wilson, E Bright; Cross, Paul C


    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. Damping of wind turbine tower vibrations

    DEFF Research Database (Denmark)

    Brodersen, Mark Laier; Pedersen, Mikkel Melters

    Damping of wind turbine vibrations by supplemental dampers is a key ingredient for the continuous use of monopiles as support for offshore wind turbines. The present thesis consists of an extended summary with four parts and appended papers [P1-P4] concerning novel strategies for damping of tower...... dominated vibrations.The first part of the thesis presents the theoretical framework for implementation of supplemental dampers in wind turbines. It is demonstrated that the feasibility of installing dampers at the bottom of the tower is significantly increased when placing passive or semiactive dampers...... in a stroke amplifying brace, which amplifies the displacement across the damper and thus reduces the desired level of damper force. For optimal damping of the two lowest tower modes, a novel toggle-brace concept for amplifying the bending deformation of the tower is presented. Numerical examples illustrate...

  20. Reduction redux. (United States)

    Shapiro, Lawrence


    Putnam's criticisms of the identity theory attack a straw man. Fodor's criticisms of reduction attack a straw man. Properly interpreted, Nagel offered a conception of reduction that captures everything a physicalist could want. I update Nagel, introducing the idea of overlap, and show why multiple realization poses no challenge to reduction so construed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Evidence of impaired learning during whole-body vibration (United States)

    Sherwood, N.; Griffin, M. J.


    A study of the effects of whole-body vibration on learning and memory was conducted, in which a context-dependent experimental design was used. Forty subjects completed a simple associative learning task, half during exposure to 16 Hz whole-body sinusoidal vertical vibration at 2.0 m s -2 r.m.s. and half while static. The results show that the rates of learning of the two groups differed, with that of the vibrated subjects significantly impaired. A second session, one week later, indicated that information learnt in one vibration environment could be recalled equally well in a different environment, suggesting no context-dependent effects on memory processes.

  2. The Influence of Tractor-Seat Height above the Ground on Lateral Vibrations

    Directory of Open Access Journals (Sweden)

    Jaime Gomez-Gil


    Full Text Available Farmers experience whole-body vibrations when they drive tractors. Among the various factors that influence the vibrations to which the driver is exposed are terrain roughness, tractor speed, tire type and pressure, rear axle width, and tractor seat height above the ground. In this paper the influence of tractor seat height above the ground on the lateral vibrations to which the tractor driver is exposed is studied by means of a geometrical and an experimental analysis. Both analyses show that: (i lateral vibrations experienced by a tractor driver increase linearly with tractor-seat height above the ground; (ii lateral vibrations to which the tractor driver is exposed can equal or exceed vertical vibrations; (iii in medium-size tractors, a feasible 30 cm reduction in the height of the tractor seat, which represents only 15% of its current height, will reduce the lateral vibrations by around 20%; and (iv vertical vibrations are scarcely influenced by tractor-seat height above the ground. The results suggest that manufacturers could increase the comfort of tractors by lowering tractor-seat height above the ground, which will reduce lateral vibrations.

  3. Experimental Analysis of a Piezoelectric Energy Harvesting System for Harmonic, Random, and Sine on Random Vibration

    Energy Technology Data Exchange (ETDEWEB)

    Cryns, Jackson W.; Hatchell, Brian K.; Santiago-Rojas, Emiliano; Silvers, Kurt L.


    Formal journal article Experimental analysis of a piezoelectric energy harvesting system for harmonic, random, and sine on random vibration Abstract: Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random and sine on random (SOR) input vibration scenarios. Additionally, the implications of source vibration characteristics on harvester design are discussed. Studies in vibration harvesting have yielded numerous alternatives for harvesting electrical energy from vibrations but piezoceramics arose as the most compact, energy dense means of energy transduction. The rise in popularity of harvesting energy from ambient vibrations has made piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. In this manuscript, variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. We characterize the source vibration by its acceleration response for repeatability and transcription to general application. The results agree with numerical and theoretical predictions for in previous literature that load optimal resistance varies with transducer natural frequency and source type, and the findings demonstrate that significant gains are seen with lower tuned transducer natural frequencies for similar source amplitudes. Going beyond idealized steady state sinusoidal and simplified random vibration input, SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibrational sources significantly alter power generation and power processing

  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)


    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. Efficient forced vibration reanalysis method for rotating electric machines (United States)

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


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

  6. Psychophysical estimate of plantar vibration sensitivity brings additional information to the detection threshold in young and elderly subjects

    Directory of Open Access Journals (Sweden)

    Yves Jammes

    Full Text Available Objective: Vibration detection threshold of the foot sole was compared to the psychophysical estimate of vibration in a wide range of amplitudes in young (20–34 years old and elderly subjects (53–67 years old. Methods: The vibration detection threshold was determined on the hallux, 5th metatarsal head, and heel at frequencies of 25, 50 and 150 Hz. For vibrations of higher amplitude (reaching 360 μm, the Stevens power function (Ψ = k * Φn allowed to obtain regression equations between the vibration estimate (Ψ and its physical magnitude (Φ, the n coefficient giving the subjective intensity in vibration perception. We searched for age-related changes in the vibration perception by the foot sole. Results: In all participants, higher n values were measured at vibration frequencies of 150 Hz and, compared to the young adults the elderly had lower n values measured at this frequency. Only in the young participants, the vibration detection threshold was lowered at 150 Hz. Conclusion: The psychophysical estimate brings further information than the vibration detection threshold which is less affected by age. Significance: The clinical interest of psychophysical vibration estimate was assessed in a patient with a unilateral alteration of foot sensitivity. Keywords: Vibration sensitivity, Vibration detection threshold, Foot sole, Elderly

  7. Coupled Vibration of Unshrouded Centrifugal Compressor Impellers. Part II: Computation of Vibration Behavior

    Directory of Open Access Journals (Sweden)

    Dirk Hagelstein


    Full Text Available The increased use of small gas turbines and turbochargers in different technical fields has led to the development of highly-loaded centrifugal compressors with extremely thin blades. Due to high rotational speed and the correspondingly high centrifugal loads, the shape of the impeller hub must also be optimized. This has led to a reduction of the thickness of the impeller disc in the outlet region. The thin parts of the impeller are very sensitive and may be damaged by the excitation of dangerous blade vibrations.

  8. An adaptive vibration control method to suppress the vibration of the maglev train caused by track irregularities (United States)

    Zhou, Danfeng; Yu, Peichang; Wang, Lianchun; Li, Jie


    The levitation gap of the urban maglev train is around 8 mm, which puts a rather high requirement on the smoothness of the track. In practice, it is found that the track irregularity may cause stability problems when the maglev train is traveling. In this paper, the dynamic response of the levitation module, which is the basic levitation structure of the urban maglev train, is investigated in the presence of track irregularities. Analyses show that due to the structural configuration of the levitation module, the vibration of the levitation gap may be amplified and "resonances" may be observed under some specified track wavelengths and train speeds; besides, it is found that the gap vibration of the rear levitation unit in a levitation module is more significant than that of the front levitation unit, which agrees well with practice. To suppress the vibration of the rear levitation gap, an adaptive vibration control method is proposed, which utilizes the information of the front levitation unit as a reference. A pair of mirror FIR (finite impulse response) filters are designed and tuned by an adaptive mechanism, and they produce a compensation signal for the rear levitation controller to cancel the disturbance brought by the track irregularity. Simulations under some typical track conditions, including the sinusoidal track profile, random track irregularity, as well as track steps, indicate that the adaptive vibration control scheme can significantly reduce the amplitude of the rear gap vibration, which provides a method to improve the stability and ride comfort of the maglev train.

  9. Vibration measurements of automobile catalyst (United States)

    Aatola, Seppo


    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.

  10. Smart accelerometer. [vibration damage detection (United States)

    Bozeman, Richard J., Jr. (Inventor)


    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.

  11. Vibrational excitation from heterogeneous catalysis

    International Nuclear Information System (INIS)

    Purvis, G.D. III; Redmon, M.J.; Woken, G. Jr.


    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

  12. Vibrational Spectral Studies of Gemfibrozil (United States)

    Benitta, T. Asenath; Balendiran, G. K.; James, C.


    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.

  13. A significant reduction in the frequency of HIV-1 drug resistance in Québec from 2001 to 2011 is associated with a decrease in the monitored viral load.

    Directory of Open Access Journals (Sweden)

    Hugues Charest

    Full Text Available BACKGROUND: HIV drug resistance represents a major threat for effective treatment. We assessed the trends in the frequency of drug resistance mutations and the monitored viral load (VL in treatment-naïve (TN and treatment-experienced (TE individuals infected with HIV-1 in Québec, Canada, between 2001 and 2011. METHODS AND FINDINGS: Resistance data were obtained from 4,105 and 5,086 genotypic tests performed on TN and TE patients, respectively. Concomitantly, 274,161 VL tests were carried out in the Province. Changes over time in drug resistance frequency and in different categories of VL were assessed using univariate logistic regression. Multiple logistic regression was used to evaluate associations between the rates of certain mutations and antiretroviral prescriptions. From 2001 to 2011, the proportion of undetectable VL test results continually increased, from 42.1% to 75.9%, while a significant decrease in the frequency of resistance mutations associated with protease inhibitors [PI (from 54% to 16%], nucleoside [NRTI (from 78% to 37% and non-nucleoside reverse transcriptase inhibitors [NNRTI (from 44% to 31%] was observed in TE patients. In TN individuals, the overall frequency of transmitted drug resistance was 13.1%. A multiple logistic regression analysis indicated that the introduction of co-formulated emtricitabine/tenofovir or emtricitabine/tenofovir/efavirenz was positively associated with the decrease of the frequency of the M184I/V mutations observed overtime (p = 0.0004. CONCLUSIONS: We observed a significant decrease in the frequency of drug resistance mutations in TE patients, concomitant with a decrease in the proportion of patients with detectable viremia. These findings may be related to both the increased potencies and adherence to therapy associated with newer antiretroviral regimens. Nevertheless, our data demonstrate that broad use of antiretrovirals does not increase the level of circulating drug resistant

  14. Induced vibrations facilitate traversal of cluttered obstacles (United States)

    Thoms, George; Yu, Siyuan; Kang, Yucheng; Li, Chen

    When negotiating cluttered terrains such as grass-like beams, cockroaches and legged robots with rounded body shapes most often rolled their bodies to traverse narrow gaps between beams. Recent locomotion energy landscape modeling suggests that this locomotor pathway overcomes the lowest potential energy barriers. Here, we tested the hypothesis that body vibrations induced by intermittent leg-ground contact facilitate obstacle traversal by allowing exploration of locomotion energy landscape to find this lowest barrier pathway. To mimic a cockroach / legged robot pushing against two adjacent blades of grass, we developed an automated robotic system to move an ellipsoidal body into two adjacent beams, and varied body vibrations by controlling an oscillation actuator. A novel gyroscope mechanism allowed the body to freely rotate in response to interaction with the beams, and an IMU and cameras recorded the motion of the body and beams. We discovered that body vibrations facilitated body rolling, significantly increasing traversal probability and reducing traversal time (P locomotor pathways in complex 3-D terrains.

  15. Vibration Monitoring of a Large Scale Heavy Haul Railway Viaduct

    Directory of Open Access Journals (Sweden)

    Busatta Fulvio


    Full Text Available In South Africa, heavy haul railway transport was introduced in the mid-1970s for the Iron Ore and the Coal Export lines. In recent decades, the expansion of existing mines, new markets and the competition of iron ore- and coal-exporting countries have led owners and operators to progressively increase the capacity of the export lines. On the one hand, operational efficiencies have been improved; on the other hand, a significant increase of the rail traffic has been experienced. Thus, bridges along the export lines are now crossed by heavier and longer trains with more frequent train passages than in the past. Increasing train loading might lead to significant consequences on structures such as dynamic amplifications and reduction of service life due to fatigue. Hence dynamic assessment and monitoring of the structural condition of bridges under actual train loading are becoming more relevant to support decision making processes. The paper presents the investigations carried out on the Olifants River Viaduct, a critical structure along the Iron Ore Export Line, in order to implement a state-of-the-art vibration monitoring system.

  16. Active Vibration Control of a Railway Vehicle Carbody Using Piezoelectric Elements (United States)

    Molatefi, Habibollah; Ayoubi, Pejman; Mozafari, Hozhabr


    In recent years and according to modern transportation development, rail vehicles are manufactured lighter to achieve higher speed and lower transportation costs. On the other hand, weight reduction of rail vehicles leads to increase the structural vibration. In this study, Active Vibration Control of a rail vehicle using piezoelectric elements is investigated. The optimal control employed as the control approach regard to the first two modes of vibration. A simplified Car body structure is modeled in Matlab using the finite element theory by considering six DOF beam element and then the Eigen functions and mode shapes are derived. The surface roughness of different classes of rail tracks have been obtained using random vibration theory and applied to the secondary suspension as the excitation of the structure; Then piezoelectric mounted where the greatest moments were captured. The effectiveness of Piezoelectric in structural vibrations attenuation of car body is demonstrated through the state space equations and its effect on modal coefficient.

  17. Viability Analysis of Waste Tires as Material for Rail Vibration and Noise Control in Modern Tram Track Systems

    Directory of Open Access Journals (Sweden)

    Caiyou Zhao


    Full Text Available This research study focused on the effect of using damping chamber elements made from waste tires on railway noise reduction. First, the energy absorption characteristics of damping chamber elements with various gradation combinations and compaction indices were measured in the laboratory using compression testing. The laboratory compression results demonstrated that the optimal gradation combination of damping chamber elements is as follows: the content of fine rubber particles is 10%, the content of coarse granules is 90%, and the optimal compaction index is 0.98. Next, the findings from the laboratory compression-test studies were used to produce damping chamber elements that were applied to a full-scale modern track model in the laboratory. The measurements of the dynamic properties indicated that the damping chamber elements could significantly reduce the vibration levels of the rail head. Finally, the damping chamber elements, which had been proven effective through laboratory dynamic tests, were widely applied to test rail sections in the field. The field tests demonstrated that damping chamber elements can significantly increase the track vibration decay rate in the frequency range of 200–10000 Hz. Therefore, damping chamber elements made from waste tires are able to control rail vibration and noise in modern tram track systems.

  18. The high level vibration test program

    International Nuclear Information System (INIS)

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


    As part of cooperative agreements between the US and Japan, tests have been performed on the seismic vibration table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Test Center (NUPEC) in Japan. The objective of the test program was to use the NUPEC vibration table to drive large diameter nuclear power piping to substantial plastic strain with an earthquake excitation and to compare the results with state-of-the-art analysis of the problem. The test model was subjected to a maximum acceleration well beyond what nuclear power plants are designed to withstand. A modified earthquake excitation was applied and the excitation level was increased carefully to minimize the cumulative fatigue damage due to the intermediate level excitations. Since the piping was pressurized, and the high level earthquake excitation was repeated several times, it was possible to investigate the effects of ratchetting and fatigue as well. Elastic and inelastic seismic response behavior of the test model was measured in a number of test runs with an increasing excitation input level up to the limit of the vibration table. In the maximum input condition, large dynamic plastic strains were obtained in the piping. Crack initiation was detected following the second maximum excitation run. Crack growth was carefully monitored during the next two additional maximum excitation runs. The final test resulted in a maximum crack depth of approximately 94% of the wall thickness. The HLVT (high level vibration test) program has enhanced understanding of the behavior of piping systems under severe earthquake loading. As in other tests to failure of piping components, it has demonstrated significant seismic margin in nuclear power plant piping

  19. Effects of music in combination with vibration in acupuncture points on the treatment of fibromyalgia. (United States)

    Weber, Augusto; Werneck, Lineu; Paiva, Eduardo; Gans, Paulo


    Fibromyalgia (FM) is a disease that causes widespread pain and increased sensitivity to pain because of a dysfunction in the central nervous system. This study investigated the effect of music combined with vibration on acupuncture points for the treatment of FM. A total of 120 patients with FM were allocated randomly to four groups (30 patients each). One group listened to a sequence of Bach's compositions. The second group was subjected to vibratory stimuli on a combination of acupuncture points on the skin. The third group (complete) underwent both procedures in a simultaneous and synchronized manner, with inclusion of binaural beats. The fourth group (control) received no stimulation. The participants underwent the experimental procedure during five sessions performed on alternate days. They were assessed by the Fibromyalgia Impact Questionnaire (FIQ) and the Health Assessment Questionnaire (HAQ) before the first session and after the last session (20 days). All groups showed a significant improvement in FIQ and HAQ scores at the evaluation after the intervention. The complete group exhibited the best result on both the FIQ and HAQ (p<0.001), and the improvement in HAQ score was significant (p<0.004). The results suggest that the placebo effect in FM may be substantial. However, comparison between groups revealed that the complete group had the greatest reduction in both FIQ and HAQ, with a significant improvement in HAQ, suggesting that the combined use of music and vibration exerts a greater effect on FM symptoms.

  20. Piezoelectric Vibration Damping Study for Rotating Composite Fan Blades (United States)

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


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

  1. Effects of different vibration exercises on bench press. (United States)

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


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

  2. State resolved vibrational relaxation modeling for strongly nonequilibrium flows (United States)

    Boyd, Iain D.; Josyula, Eswar


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

  3. Hand-arm vibration in tropical rain forestry workers. (United States)

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


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

  4. Vibration Considerations for Cryogenic Tanks Using Glass Bubbles Insulation (United States)

    Werlink, Rudolph J.; Fesmire, James E.; Sass, Jared P.


    The use of glass bubbles as an efficient and practical thermal insulation system has been previously demonstrated in cryogenic storage tanks. One such example is a spherical, vacuum-jacketed liquid hydrogen vessel of 218,000 liter capacity where the boiloff rate has been reduced by approximately 50 percent. Further applications may include non-stationary tanks such as mobile tankers and tanks with extreme duty cycles or exposed to significant vibration environments. Space rocket launch events and mobile tanker life cycles represent two harsh cases of mechanical vibration exposure. A number of bulk fill insulation materials including glass bubbles, perlite powders, and aerogel granules were tested for vibration effects and mechanical behavior using a custom design holding fixture subjected to random vibration on an Electrodynamic Shaker. The settling effects for mixtures of insulation materials were also investigated. The vibration test results and granular particle analysis are presented with considerations and implications for future cryogenic tank applications. A thermal performance update on field demonstration testing of a 218,000 L liquid hydrogen storage tank, retrofitted with glass bubbles, is presented. KEYWORDS: Glass bubble, perlite, aerogel, insulation, liquid hydrogen, storage tank, mobile tanker, vibration.

  5. Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: II. Significant reduction of strand movement and strand damage in short twist pitch CICCs

    International Nuclear Information System (INIS)

    Sanabria, Carlos; Lee, Peter J; Starch, William; Larbalestier, David C; Devred, Arnaud


    Prototype cable-in-conduit-conductors (CICCs) destined for use in the toroidal field and central solenoid coils of the ITER experimental fusion reactor underwent severe cyclic loading in the SULTAN facility. Their autopsies revealed significant and permanent transverse strand migration due to the large Lorentz forces of the SULTAN test. The movement resulted in a 3%–7% void fraction increase on the low pressure (LP) side of the longer twist pitch CICCs. However, short twist pitch conductors exhibited less than 1% void fraction increase in the LP side, as well as a complete absence of the Nb 3 Sn filament fractures observed in the longer twist pitch conductors. We report here a detailed strand-to-cable analysis of short and longer ‘baseline’ twist pitch CICCs. It was found that the use of internal tin (IT) strands in the longer ‘baseline’ twist pitch CICCs can be beneficial possibly because of their superior stiffness—which better resist strand movement—while the use of bronze process strands showed more movement and poorer cyclic test performance. This was not the case for the short twist pitch CICC. Such conductor design seems to work well with both strand types. But it was found that despite the absence of filament fractures, the short twist pitch CICC made from the IT strands studied here developed severe strand distortion during cabling which resulted in diffusion barrier breaks and Sn contamination of the Cu stabilizer during the heat treatment. Conversely, the short twist pitch CICC made from bronze process strands preserved diffusion barrier integrity. (paper)

  6. Significant reduction of normal tissue dose by proton radiotherapy compared with three-dimensional conformal or intensity-modulated radiation therapy in Stage I or Stage III non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Chang, Joe Y.; Zhang Xiaodong; Wang Xiaochun; Kang Yixiu; Riley, Beverly C.; Bilton, Stephen C.; Mohan, Radhe; Komaki, Ritsuko; Cox, James D.


    Purpose: To compare dose-volume histograms (DVH) in patients with non-small-cell lung cancer (NSCLC) treated by photon or proton radiotherapy. Methods and Materials: Dose-volume histograms were compared between photon, including three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and proton plans at doses of 66 Gy, 87.5 Gy in Stage I (n = 10) and 60-63 Gy, and 74 Gy in Stage III (n 15). Results: For Stage I, the mean total lung V5, V10, and V20 were 31.8%, 24.6%, and 15.8%, respectively, for photon 3D-CRT with 66 Gy, whereas they were 13.4%, 12.3%, and 10.9%, respectively, with proton with dose escalation to 87.5 cobalt Gray equivalents (CGE) (p = 0.002). For Stage III, the mean total lung V5, V10, and V20 were 54.1%, 46.9%, and 34.8%, respectively, for photon 3D-CRT with 63 Gy, whereas they were 39.7%, 36.6%, and 31.6%, respectively, for proton with dose escalation to 74 CGE (p = 0.002). In all cases, the doses to lung, spinal cord, heart, esophagus, and integral dose were lower with proton therapy even compared with IMRT. Conclusions: Proton treatment appears to reduce dose to normal tissues significantly, even with dose escalation, compared with standard-dose photon therapy, either 3D-CRT or IMRT

  7. Significant reduction of peripheral blood interleukin-35 and CD4+EBI3+ T cells, which are negatively correlated with an increase in the plasma IL-17 and cTnI level, in viral myocarditis patients

    Directory of Open Access Journals (Sweden)

    Han Ouyang


    Full Text Available Introduction: Viral myocarditis (VMC has become an increasingly common heart disease that endangers human health. In the present study, the plasma interleukin-35 (IL-35 level and the percentage of CD4 + EBI3 + T cells in VMC patients were detected to investigate the significance of changes in these parameters in the plasma of VMC patients and their association with the disease. Material and methods: ELISA was performed to detect the plasma IL-35 level and the percentage of peripheral blood CD4 + EBI3 + T cells in 40 VMC patients and in 20 healthy individuals. Moreover, the plasma IL-17 levels in the VMC patients and in the healthy individuals were detected using an ELISA, and the cardiac Troponin-I (cTnI levels were detected using a chemiluminescent microparticle immunoassay to compare the differences in the groups. Results : Plasma IL-35 level and the percentage of CD4 + EBI3 + T cells in acute phase VMC patients was lower than that in the healthy control group and the convalescent phase VMC patients. Additionally, the plasma IL-35 level in the VMC patients exhibited a negative correlation with the levels of cTnI and IL-17. The percentage of CD4 + EBI3 + T cells also showed a negative correlation with the levels of cTnI and IL-17. Conclusions : The plasma IL-35 level and the percentage of CD4 + EBI3 + T cells in VMC patients was reduced, and the amount of the decrease was associated with the severity of the disease. These results suggest that IL-35 and CD4 + EBI3 + T might play important roles in the progression of VMC and could be used as indictors of the disease.

  8. Optimal reduction of flexible dynamic system

    International Nuclear Information System (INIS)

    Jankovic, J.


    Dynamic system reduction is basic procedure in various problems of active control synthesis of flexible structures. In this paper is presented direct method for system reduction by explicit extraction of modes included in reduced model form. Criterion for optimal system discrete approximation in synthesis reduced dynamic model is also presented. Subjected method of system decomposition is discussed in relation to the Schur method of solving matrix algebraic Riccati equation as condition for system reduction. By using exposed method procedure of flexible system reduction in addition with corresponding example is presented. Shown procedure is powerful in problems of active control synthesis of flexible system vibrations

  9. Reduction - competitive tomorrow

    International Nuclear Information System (INIS)

    Worley, L.; Bargerstock, S.


    Inventory reduction is one of the few initiatives that represent significant cost-reduction potential that does not result in personnel reduction. Centerior Energy's Perry nuclear power plant has embarked on an aggressive program to reduce inventory while maintaining plant material availability. Material availability to the plant was above 98%, but at an unacceptable 1994 inventory book value of $47 million with inventory carrying costs calculated at 30% annually

  10. Experimental Analysis of a Piezoelectric Energy Harvesting System for Harmonic, Random, and Sine on Random Vibration

    Directory of Open Access Journals (Sweden)

    Jackson W. Cryns


    Full Text Available Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random, and sine on random (SOR input vibration scenarios; the implications of source vibration characteristics on harvester design are discussed. The rise in popularity of harvesting energy from ambient vibrations has made compact, energy dense piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. Variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. The results agree with numerical and theoretical predictions in the previous literature for optimal power harvesting in sinusoidal and flat broadband vibration scenarios. Going beyond idealized steady-state sinusoidal and flat random vibration input, experimental SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibration sources significantly alter power generation and processing requirements by varying harvested power, shifting optimal conditioning impedance, inducing voltage fluctuations, and ultimately rendering idealized sinusoidal and random analyses incorrect.

  11. Vibration characteristics of dental high-speed turbines and speed-increasing handpieces. (United States)

    Poole, Ruth L; Lea, Simon C; Dyson, John E; Shortall, Adrian C C; Walmsley, A Damien


    Vibrations of dental handpieces may contribute to symptoms of hand-arm vibration syndrome in dental personnel and iatrogenic enamel cracking in teeth. However, methods for measuring dental handpiece vibrations have previously been limited and information about vibration characteristics is sparse. This preliminary study aimed to use a novel approach to assess the vibrations of unloaded high-speed handpieces in vitro. Maximum vibration displacement amplitudes of five air turbines and two speed-increasing handpieces were recorded whilst they were operated with and without a rotary cutting instrument (RCI) using a scanning laser vibrometer (SLV). RCI rotation speeds, calculated from frequency peaks, were consistent with expected values. ANOVA statistical analysis indicated significant differences in vibrations between handpiece models (p0.11). Operating handpieces with a RCI resulted in greater vibrations than with no RCI (pmeasurement exceeded 4 microm for the handpieces in the current test setup (implying that these vibrations may be unlikely to cause adverse effects), this study has formed the basis for future work which will include handpiece vibration measurements whilst cutting under clinically representative loads.

  12. Application of vibration to wrist and hand skin affects fingertip tactile sensation (United States)

    Lakshminarayanan, Kishor; Lauer, Abigail W; Ramakrishnan, Viswanathan; Webster, John G; Seo, Na Jin


    A recent study showed that fingertip pads’ tactile sensation can improve by applying imperceptible white-noise vibration to the skin at the wrist or dorsum of the hand in stroke patients. This study further examined this behavior by investigating the effect of both imperceptible and perceptible white-noise vibration applied to different locations within the distal upper extremity on the fingertip pads’ tactile sensation in healthy adults. In 12 healthy adults, white-noise vibration was applied to one of four locations (dorsum hand by the second knuckle, thenar and hypothenar areas, and volar wrist) at one of four intensities (zero, 60%, 80%, and 120% of the sensory threshold for each vibration location), while the fingertip sensation, the smallest vibratory signal that could be perceived on the thumb and index fingertip pads, was assessed. Vibration intensities significantly affected the fingertip sensation (P sensation (P sensation (P sensation (P > 0.01), all compared with the zero vibration condition. This effect with vibration intensity conforms to the stochastic resonance behavior. Nonspecificity to the vibration location suggests the white-noise vibration affects higher level neuronal processing for fingertip sensing. Further studies are needed to elucidate the neural pathways for distal upper extremity vibration to impact fingertip pad tactile sensation. PMID:26177959

  13. Vibrational spectroscopy of proteins

    International Nuclear Information System (INIS)

    Schwaighofer, A.


    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

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

    International Nuclear Information System (INIS)

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


    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.)

  15. A new potential energy surface for vibration-vibration coupling in HF-HF collisions. Formulation and quantal scattering calculations (United States)

    Schwenke, David W.; Truhlar, Donald G.


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

  16. Vibration control of a cluster of buildings through the Vibrating Barrier (United States)

    Tombari, A.; Garcia Espinosa, M.; Alexander, N. A.; Cacciola, P.


    A novel device, called Vibrating Barrier (ViBa), that aims to reduce the vibrations of adjacent structures subjected to ground motion waves has been recently proposed. The ViBa is a structure buried in the soil and detached from surrounding buildings that is able to absorb a significant portion of the dynamic energy arising from the ground motion. The working principle exploits the dynamic interaction among vibrating structures due to the propagation of waves through the soil, namely the structure-soil-structure interaction. In this paper the efficiency of the ViBa is investigated to control the vibrations of a cluster of buildings. To this aim, a discrete model of structures-site interaction involving multiple buildings and the ViBa is developed where the effects of the soil on the structures, i.e. the soil-structure interaction (SSI), the structure-soil-structure interaction (SSSI) as well as the ViBa-soil-structures interaction are taken into account by means of linear elastic springs. Closed-form solutions are derived to design the ViBa in the case of harmonic excitation from the analysis of the discrete model. Advanced finite element numerical simulations are performed in order to assess the efficiency of the ViBa for protecting more than a single building. Parametric studies are also conducted to identify beneficial/adverse effects in the use of the proposed vibration control strategy to protect cluster of buildings. Finally, experimental shake table tests are performed to a prototype of a cluster of two buildings protected by the ViBa device for validating the proposed numerical models.

  17. Adaptive learning algorithms for vibration energy harvesting

    International Nuclear Information System (INIS)

    Ward, John K; Behrens, Sam


    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%

  18. Vibrations of wind power plants; Schwingungen von Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)



    Within the meeting of the department vibration engineering of the Association of German Engineers (Duesseldorf, Federal Republic of Germany) between 3rd and 4th February, 2010 in Hanover (Federal Republic of Germany) the following lectures are presented: (1) Reduction of forced strengths generated by wagging and snaking of the rotor in the power strain of wind power plants (F. Mitsch); (2) Reduction of vibrations at wind power plants by means of active additional systems (S. Katz, S. Pankoke, N. Loix); (3) Reduction of vibrations by means of balancing and alignment (E. Becker, M. Kenzler); (4) Active absorber for reducing tonal emissions of vibration at wind power plants (R. Neugebauer, M. Linke, H. Kunze, M. Ulrich); (5) Control structures for damping torsion vibrations and peak loads in the power strain of wind power converters (C. Sourkounis); (6) Possibilities of a non-contact investigation of vibrations at wind power plants (R. Behrendt, E. Reimers, H. Wiegers); (7) Influences on the loadability of CMS statements (R. Wirth); (8) Recording modal structural properties with sensor grids and methods of operational modal analysis (A. Friedmann, D. Mayer, M. Koch, M. Kauba, T. Melz); (9) Early failure detection of damages of roller bearings in wind power gear units with variable speed (B. Hacke, G. Poll); (10) Condition monitoring in wind power plants - structure monitoring and life time monitoring of wind power plants (SCMS and LCMS) (H. Lange); (11) Development of a model-based structural health monitoring system for condition monitoring of rotor blades (C. Ebert, H. Friedmann, F.O. Henkel, B. Frankenstein, L. Schubert); (12) Efficient remote monitoring at wind power plants by means of an external diagnosis centre (G. Ceglarek); (13) Accurate turbine modelling at component and assembly level for durability and acoustic analysis (D. v. Werner, W. Hendricx); (14) Possibilities of the investigation of the dynamic behaviour of power strains in wind power plants by

  19. Blade Vibration Measurement System for Unducted Fans (United States)

    Marscher, William


    With propulsion research programs focused on new levels of efficiency and noise reduction, two avenues for advanced gas turbine technology are emerging: the geared turbofan and ultrahigh bypass ratio fan engines. Both of these candidates are being pursued as collaborative research projects between NASA and the engine manufacturers. The high bypass concept from GE Aviation is an unducted fan that features a bypass ratio of over 30 along with the accompanying benefits in fuel efficiency. This project improved the test and measurement capabilities of the unducted fan blade dynamic response. In the course of this project, Mechanical Solutions, Inc. (MSI) collaborated with GE Aviation to (1) define the requirements for fan blade measurements; (2) leverage MSI's radar-based system for compressor and turbine blade monitoring; and (3) develop, validate, and deliver a noncontacting blade vibration measurement system for unducted fans.

  20. FORTE spacecraft vibration mitigation. Final report

    International Nuclear Information System (INIS)

    Maly, J.R.


    This report documents work that was performed by CSA Engineering, Inc., for Los Alamos National Laboratory (LANL), to reduce vibrations of the FORTE spacecraft by retrofitting damped structural components into the spacecraft structure. The technical objective of the work was reduction of response at the location of payload components when the structure is subjected to the dynamic loading associated with launch and proto-qualification testing. FORTE is a small satellite that will be placed in orbit in 1996. The structure weighs approximately 425 lb, and is roughly 80 inches high and 40 inches in diameter. It was developed and built by LANL in conjunction with Sandia National Laboratories Albuquerque for the United States Department of Energy. The FORTE primary structure was fabricated primarily with graphite epoxy, using aluminum honeycomb core material for equipment decks and solar panel substrates. Equipment decks were bonded and bolted through aluminum mounting blocks to adjoining structure

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  2. The role of electron-impact vibrational excitation in electron transport through gaseous tetrahydrofuran

    Energy Technology Data Exchange (ETDEWEB)

    Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Do, T. P. T. [School of Education, Can Tho University, Campus II, 3/2 Street, Xuan Khanh, Ninh Kieu, Can Tho City (Viet Nam); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Konovalov, D. A.; White, R. D. [College of Science, Technology and Engineering, James Cook University, Townsville (Australia); Brunger, M. J., E-mail:, E-mail: [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Jones, D. B., E-mail:, E-mail: [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia)


    In this paper, we report newly derived integral cross sections (ICSs) for electron impact vibrational excitation of tetrahydrofuran (THF) at intermediate impact energies. These cross sections extend the currently available data from 20 to 50 eV. Further, they indicate that the previously recommended THF ICS set [Garland et al., Phys. Rev. A 88, 062712 (2013)] underestimated the strength of the electron-impact vibrational excitation processes. Thus, that recommended vibrational cross section set is revised to address those deficiencies. Electron swarm transport properties were calculated with the amended vibrational cross section set, to quantify the role of electron-driven vibrational excitation in describing the macroscopic swarm phenomena. Here, significant differences of up to 17% in the transport coefficients were observed between the calculations performed using the original and revised cross section sets for vibrational excitation.

  3. Signal Processing Methods for Removing the Effects of Whole Body Vibration upon Speech (United States)

    Bitner, Rachel M.; Begault, Durand R.


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

  4. Active Control of Parametric Vibrations in Coupled Rotor-Blade Systems

    DEFF Research Database (Denmark)

    Christensen, Rene Hardam; Santos, Ilmar


    of modes. The designed control scheme is applied to a coupled rotor-blade system and dynamic responses are numerically evaluated. Such responses show that the vibrations are efficiently reduced. Frequency response diagrams demonstrate that both basis and parametric vibration modes are significantly...... the model becomes periodic-variant. In order to reduce basis as well as parametric vibrations by means of active control in such systems a time-variant control strategy has to be adopted. This paper presents a methodology for designing an active controller to reduce vibrations in a coupled rotor......-blade system. The main aim is to control blade as well as hub vibrations in such a system by means of active control with focus on reducing the parametric vibration. A periodic state feedback controller is designed by transforming the system into a linear time-invariant form. Using this a controller...

  5. PC based vibration monitoring system

    International Nuclear Information System (INIS)

    Jain, Sanjay K.; Roy, D.A.; Pithawa, C.K.; Patil, R.K.


    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)

  6. 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


    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)

  7. Optimal Damping of Stays in Cable-Stayed Bridges for In-Plane Vibrations

    DEFF Research Database (Denmark)

    Jensen, C.N.; Nielsen, S.R.K.; Sørensen, John Dalsgaard


    cable-stayed bridges are often designed as twin cables with a spacing of, say 1m. In such cases, it is suggested in the paper to suppress the mentioned in-plane types of vibrations by means of a tuned mass–damper (TMD) placed between the twin cables at their midpoints. The TMD divides the stay into four......Significant vibrations have been reported in stays of recently constructed cable stayed bridges. The vibrations appear as in-plane vibrations that may be caused by rain–wind- induced aeroelastic interaction or by resonance excitation of the cables from the motion of the pylons. The stays of modern...

  8. Process energy reduction

    International Nuclear Information System (INIS)

    Lowthian, W.E.


    Process Energy Reduction (PER) is a demand-side energy reduction approach which complements and often supplants other traditional energy reduction methods such as conservation and heat recovery. Because the application of PER is less obvious than the traditional methods, it takes some time to learn the steps as well as practice to become proficient in its use. However, the benefit is significant, often far outweighing the traditional energy reduction approaches. Furthermore, the method usually results in a better process having less waste and pollution along with improved yields, increased capacity, and lower operating costs

  9. A 6-DOF vibration isolation system for hydraulic hybrid vehicles (United States)

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


    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. Significant reductions in heart and lung doses using semi lateral ...

    African Journals Online (AJOL)

    Introduction: Various treatment techniques as breath hold techniques have been developed to spare the heart and lung in breast cancer patients receiving adjuvant radiotherapy. Purpose: to compare the heart and lung dosimetric parameters of semi lateral decubitus technique with and without deep inspiration breath hold ...

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

    Directory of Open Access Journals (Sweden)

    Sarah Harrisson


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

  12. Anti-Tuberculosis Bacteriophage D29 Delivery with a Vibrating Mesh Nebulizer, Jet Nebulizer, and Soft Mist Inhaler. (United States)

    Carrigy, Nicholas B; Chang, Rachel Y; Leung, Sharon S Y; Harrison, Melissa; Petrova, Zaritza; Pope, Welkin H; Hatfull, Graham F; Britton, Warwick J; Chan, Hak-Kim; Sauvageau, Dominic; Finlay, Warren H; Vehring, Reinhard


    To compare titer reduction and delivery rate of active anti-tuberculosis bacteriophage (phage) D29 with three inhalation devices. Phage D29 lysate was amplified to a titer of 11.8 ± 0.3 log 10 (pfu/mL) and diluted 1:100 in isotonic saline. Filters captured the aerosolized saline D29 preparation emitted from three types of inhalation devices: 1) vibrating mesh nebulizer; 2) jet nebulizer; 3) soft mist inhaler. Full-plate plaque assays, performed in triplicate at multiple dilution levels with the surrogate host Mycobacterium smegmatis, were used to quantify phage titer. Respective titer reductions for the vibrating mesh nebulizer, jet nebulizer, and soft mist inhaler were 0.4 ± 0.1, 3.7 ± 0.1, and 0.6 ± 0.3 log 10 (pfu/mL). Active phage delivery rate was significantly greater (p pfu/min) than for the jet nebulizer (5.4x10 4  ± 1.3x10 4 pfu/min). The soft mist inhaler delivered 4.6x10 6  ± 2.0x10 6 pfu per 11.6 ± 1.6 μL ex-actuator dose. Delivering active phage requires a prudent choice of inhalation device. The jet nebulizer was not a good choice for aerosolizing phage D29 under the tested conditions, due to substantial titer reduction likely occurring during droplet production. The vibrating mesh nebulizer is recommended for animal inhalation studies requiring large amounts of D29 aerosol, whereas the soft mist inhaler may be useful for self-administration of D29 aerosol.

  13. Focal vibration of quadriceps muscle enhances leg power and decreases knee joint laxity in female volleyball players. (United States)

    Brunetti, O; Botti, F M; Roscini, M; Brunetti, A; Panichi, R; Filippi, G M; Biscarini, A; Pettorossi, V E


    This double-blind randomized controlled study aims at determining the effect of repeated muscle vibration (rMV) on explosive and reactive leg power and on knee laxity of female volleyball players. Eighteen voluntary volleyball athletes, belonging to the same senior regional level team (age=22.7 ± 3 years, height=180.3 ± 5 cm, mass= 64 ± 4 kg) were assigned to three groups (N.=6) for vibration on contracted quadriceps (VC), vibration on relaxed muscle (VR), and sham vibration (NV), respectively. Intervention consisted in 3 rMV sessions performed in 3 consecutive days. In each session, 100 Hz, 300-500 μm amplitude vibratory stimuli were bilaterally delivered to the quadriceps in three consecutive 10-minutes applications. Explosive and reactive leg power and knee joint laxity were evaluated 1 day before, and 1, 30, and 240 days after intervention. In VC group, explosive and reactive leg power increased respectively by ~16% and ~9% at 1 day, by ~19% and ~11% at 30 days and by ~26% and ~13% at 240 days, concomitantly knee laxity decreased by ~6%, ~15% and ~18% at the same times. These changes were significantly larger than in the other groups, in which leg power increment and knee joint laxity reduction remained close to ~3%, ~5% and ~10% at 1, 30 and 240 days, respectively. Combined bilateral voluntary contraction and rMV of the quadriceps muscles is a short-lasting, non-invasive technique that can significantly and persistently improve muscle performance and knee laxity in volleyball women players.

  14. On generalized fractional vibration equation

    International Nuclear Information System (INIS)

    Dai, Hongzhe; Zheng, Zhibao; Wang, Wei


    Highlights: • The paper presents a generalized fractional vibration equation for arbitrary viscoelastically damped system. • Some classical vibration equations can be derived from the developed equation. • The analytic solution of developed equation is derived under some special cases. • The generalized equation is particularly useful for developing new fractional equivalent linearization method. - Abstract: In this paper, a generalized fractional vibration equation with multi-terms of fractional dissipation is developed to describe the dynamical response of an arbitrary viscoelastically damped system. It is shown that many classical equations of motion, e.g., the Bagley–Torvik equation, can be derived from the developed equation. The Laplace transform is utilized to solve the generalized equation and the analytic solution under some special cases is derived. Example demonstrates the generalized transfer function of an arbitrary viscoelastic system.

  15. General vibration monitoring: Experimental hall

    International Nuclear Information System (INIS)

    Jendrzejczyk, J.A.; Wambsganss, M.W.; Smith, R.K.


    The reported vibration data were generated from measurements made on the experimental hall floor on December 2, 1992. At the time of the measurements, the ESRF hydrolevel was set-up in the Early Assembly Area (EAA) of the experimental hall and was being used to measure static displacement (settlement) of the floor. The vibration measurement area was on and adjacent to the EAA, in the vicinity of the ESRF hydrolevel test which was in progress. This report summarizes the objectives, instrumentation, measurement locations, observations, and conclusions, and provides selected results in the form of RMS vs. time plots, and power spectral densities from which frequency information can be derived. Measured response amplitudes were within the vibration criteria established for the APS

  16. Application of Sub-Micrometer Vibrations to Mitigate Bacterial Adhesion

    Directory of Open Access Journals (Sweden)

    Will R. Paces


    Full Text Available As a prominent concern regarding implantable devices, eliminating the threat of opportunistic bacterial infection represents a significant benefit to both patient health and device function. Current treatment options focus on chemical approaches to negate bacterial adhesion, however, these methods are in some ways limited. The scope of this study was to assess the efficacy of a novel means of modulating bacterial adhesion through the application of vibrations using magnetoelastic materials. Magnetoelastic materials possess unique magnetostrictive property that can convert a magnetic field stimulus into a mechanical deformation. In vitro experiments demonstrated that vibrational loads generated by the magnetoelastic materials significantly reduced the number of adherent bacteria on samples exposed to Escherichia coli, Staphylococcus epidermidis and Staphylococcus aureus suspensions. These experiments demonstrate that vibrational loads from magnetoelastic materials can be used as a post-deployment activated means to deter bacterial adhesion and device infection.

  17. Force illusions and drifts observed during muscle vibration. (United States)

    Reschechtko, Sasha; Cuadra, Cristian; Latash, Mark L


    We explored predictions of a scheme that views position and force perception as a result of measuring proprioceptive signals within a reference frame set by ongoing efferent process. In particular, this hypothesis predicts force illusions caused by muscle vibration and mediated via changes in both afferent and efferent components of kinesthesia. Healthy subjects performed accurate steady force production tasks by pressing with the four fingers of one hand (the task hand) on individual force sensors with and without visual feedback. At various times during the trials, subjects matched the perceived force using the other hand. High-frequency vibration was applied to one or both of the forearms (over the hand and finger extensors). Without visual feedback, subjects showed a drop in the task hand force, which was significantly smaller under the vibration of that forearm. Force production by the matching hand was consistently higher than that of the task hand. Vibrating one of the forearms affected the matching hand in a manner consistent with the perception of higher magnitude of force produced by the vibrated hand. The findings were consistent between the dominant and nondominant hands. The effects of vibration on both force drift and force mismatching suggest that vibration led to shifts in both signals from proprioceptors and the efferent component of perception, the referent coordinate and/or coactivation command. The observations fit the hypothesis on combined perception of kinematic-kinetic variables with little specificity of different groups of peripheral receptors that all contribute to perception of forces and coordinates. NEW & NOTEWORTHY We show that vibration of hand/finger extensors produces consistent errors in finger force perception. Without visual feedback, finger force drifted to lower values without a drift in the matching force produced by the other hand; hand extensor vibration led to smaller finger force drift. The findings fit the scheme with

  18. 16 x 16 Vantage+ Fuel Assembly Flow Vibrational Testing

    International Nuclear Information System (INIS)

    Chambers, Martin; Kurincic, Bojan


    Nuklearna Elektrarna Krsko (NEK) has experienced leaking fuel after increasing the cycle duration to 18 months. The leaking fuel mechanism has predominantly been consistent over multiple cycles and is typically observed in highly irradiated Fuel Assemblies (FA) after around 4 years of continuous operation that were located at the core periphery (baffle). The cause of the leaking fuel is due to Grid-To-Rod-Fretting (GRTF) and occasional debris fretting. NEK utilises a 16x16 Vantage+ FA design with all Inconel structural mixing vane grids (8 in total), Zirlo thimbles, Integral Fuel Burnable Absorber (IFBA) rods with enriched ZrB2, enriched Annular Blanket, Debris Filter Bottom Nozzle (DFBN), Removable Top Nozzle (RTN) and Zirlo fuel cladding material with a high burnup capability of 60 GWD/MTU. Numerous design and operational changes are thought to have reduced the original 16x16 FA design margin to fretting resistance of either vibration or its wear work rate, such as significant power uprate (spring force loss, rod creep down...), operational cycle duration increase from 12 to 18 months (increasing residence time as well as lead FA and fuel rod burnup values), Reactor Coolant System flow increase (increased vibration), removal of Thimble Plugs (increased bypass flow, increased vibration) and Zirc-4 to Zirlo cladding change (decreasing wear work rate). The fuel rod to grid spring as well as dimple contact areas are relatively smaller than other FA designs that exhibit good in-reactor fretting performance. A FA design change project to address the small rod to dimple / spring contact area and utilise fuel cladding oxide coating is currently being pursued with the fuel supplier. The FA vibrational properties are very important to the in-reactor FA performance and reliability. The 16x16 Vantage+ vibrational testing was performed with a full size FA in the Fuel Assembly Compatibility Testing (FACTS) loop that is able to provide full flow rates at elevated temperature

  19. Fundamental Vibration of Molecular Hydrogen (United States)

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


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

  20. The Shock and Vibration Bulletin. Part 2. Vibration Analysis. (United States)


    J.N. Tait, Naval Air Development Center, Warminster, PA EVALUATION OF AN ADAPTIVE FILTER AS A DIGITAL TRACKING FILTER D.O. Smallwood and D.L. Gregory...Oklahoma Norman , Oklahoma In contrast to the considerable information abailable on free vibration of isotropic plates, there is only a very limited

  1. Magnetoelastic stability and vibrations of superconducting magnets. Progress report, September 1, 1975--March 31, 1976

    International Nuclear Information System (INIS)

    Moon, F.C.


    Buckling and vibration problems in small superconducting models of tokamak coils are studied. Observations are reported on thermoelastic buckling of epoxy potted superconducting coils producing significant out of plane deformations due to differences in thermal expansion coefficients. The damping of free vibrations in the coils is also investigated

  2. Shock and Vibration. Volume 1, Issue 1

    National Research Council Canada - National Science Library

    Pilkey, Walter D


    ..., and earthquake engineering. Among the specific areas to be covered are vibration testing and control, vibration condition monitoring and diagnostics, shock hardenings, modal technology, shock testing, data acquisition, fluid...

  3. Isotope separation using vibrationally excited molecules

    International Nuclear Information System (INIS)


    This invention relates to isotope separation employing isotopically selective vibrational excitation and vibration-translation reactions of the excited particles. Uranium enrichment, using uranium hexafluoride, is a particular embodiment. (U.K.)

  4. Predicting Statistical Distributions of Footbridge Vibrations

    DEFF Research Database (Denmark)

    Pedersen, Lars; Frier, Christian


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

  5. Application of eigenfunction orthogonalities to vibration problems

    CSIR Research Space (South Africa)

    Fedotov, I


    Full Text Available The modelling of vibration problems is of great importance in engineering. A popular method of analysing such problems is the variational method. The simplest vibration model is represented using the example of a long rod. Two kinds...

  6. Evaluation of the vibration attenuation properties of an air-inflated cushion with two different heavy machinery seats in multi-axis vibration environments including jolts. (United States)

    Ji, Xiaoxu; Eger, Tammy R; Dickey, James P


    Seats and cushions can attenuate whole-body vibration (WBV) exposures and minimize health risks for heavy machine operators. We successfully developed neural network (NN) algorithms to identify the vibration attenuation properties for four different seating conditions (seat/cushion combinations), and implemented each of the NN models to predict the equivalent daily exposure A(8) values for various vehicles in the forestry and mining environments. We also evaluated the performance of the new prototype No-Jolt™ air-inflated cushion and the original cushion of each seat with jolt exposures. We observed that the air cushion significantly improved the vibration attenuation properties of the seat that initially had good performance, but not for the seat that had relatively poor vibration attenuation properties. In addition, operator's anthropometrics and sex influenced the performance of the air-inflated cushion when the vibration environment included jolt exposures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Vibration analysis of the synchronous motor of a propane compressor

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    International Nuclear Information System (INIS)

    Jiang, Qing-Tang.


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

  9. Structural impact response for assessing railway vibration induced on buildings (United States)

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


    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.

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

    International Nuclear Information System (INIS)

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


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

  11. Diagnostic aspects of vibration-induced white finger. (United States)

    Olsen, Niels


    Vibration-induced white finger (VWF) is a secondary type of Raynaud's phenomenon (RP) caused by exposure to hand-arm vibration. The present review concerns the cold-provoked attack of RP in vasospastic VWF. It concentrates on the most common clinical and laboratory methods used to diagnose RP in vibration-exposed subjects. Some physiological aspects of the attack of RP are mentioned to elucidate the diagnostic principles of the tests. Anamnestic diagnostics by medical interviews and questionnaires as well as cold-provocation tests with detection of finger colour, finger systolic blood pressure (FSP), recovery time of finger skin temperature and recovery time of normal nail colour after nail compression are mentioned. The discriminative capacity and the reproducibility of the tests are discussed. Cold-provocation tests with detection of finger colour or zero FSP during cooling are recommended to be used if an attack of RP has to be registered for diagnostic or medico-legal purposes in individual cases. An abnormal reduction in FSP during cooling makes a history of RP very probable and is a suitable laboratory test for groups of subjects. Both recovery tests may be useful screening tests in field studies of vibration-exposed subject groups.

  12. Gravity Effects on the Free Vibration of a Graphite Column

    International Nuclear Information System (INIS)

    Ki, Dong-Ok; Kim, Jong-Bum; Park, Keun-Bae; Lee, Won-Jae


    The gravity effects on the free vibration of a graphite column are studied. Graphite block is a key component of a HTGR (High Temperature Gas Cooled Reactor). The major core elements, such as the fuel blocks and neutron reflector blocks, of HTTR (High Temperature Test Reactor, Japan) and GT-MHR (Gas Turbine- Modular Helium Reactor, USA) consist of stacked hexagonal graphite blocks forming a group of columns. The vibration of the columns induced by earthquakes may lead to solid impacts between graphite blocks and structural integrity problems. The study of free vibration characteristics of the graphite block column is the first step in the core internal structure dynamic analysis. Gravity force bring a negative stiffness term to the transverse vibration analysis of heavy long column structures, and results in natural frequency reductions. Generally it is not considered in the not so tall structure cases, because the gravity term makes the analysis and design complicated. Therefore it is important to check whether the gravity effect is severe or not

  13. Fiber optic vibration sensor using bifurcated plastic optical fiber (United States)

    Abdullah, M.; Bidin, N.; Yasin, M.


    An extrinsic fiber optic vibration sensor is demonstrated for a fiber optic displacement sensor based on a bundled multimode fiber to measure a vibration frequency ranging from 100 until 3000 Hz. The front slope has a sensitivity of 0.1938mV/mm and linearity of 99.7% within a measurement range between 0.15-3.00 mm. By placing the diaphragm of the concave load-speaker within the linear range from the probe, the frequency of the vibration can be measured with error percentage of less than 1.54%. The graph of input against output frequency for low, medium and high frequency range show very high linearity up to 99%. Slope for low, medium, and high frequency range are calculated as 1.0026, 0.9934, and 1.0007 respectively. Simplicity, long term stability, low power consumption, wide dynamic and frequency ranges, noise reduction, ruggedness, linearity and light weight make it promising alternative to other well-establish methods for vibration frequency measurement.

  14. Effect of vibration loading on the fatigue life of part-through notched pipe

    International Nuclear Information System (INIS)

    Mittal, Rahul; Singh, P.K.; Pukazhendi, D.M.; Bhasin, V.; Vaze, K.K.; Ghosh, A.K.


    A systematic experimental and analytical study has been carried out to investigate the effect of vibration loading on the fatigue life of the piping components. Three Point bend (TPB) specimens machined from the actual pipe have been used for the evaluation of Paris constants by carrying out the experiments under vibration + cyclic and cyclic loading as per the ASTM Standard E647. These constants have been used for the prediction of the fatigue life of the pipe having part-through notch of a/t = 0.25 and aspect ratio (2c/a) of 10. Predicted results have shown the reduction in fatigue life of the notched pipe subjected to vibration + cyclic loading by 50% compared to that of cyclic loading. Predicted results have been validated by carrying out the full-scale pipe (with part-through notch) tests. Notched pipes were subjected to loading conditions such that the initial stress-intensity factor remains same as that of TPB specimen. Experimental results of the full-scale pipe tests under vibration + cyclic loading has shown the reduction in fatigue life by 70% compared to that of cyclic loading. Fractographic examination of the fracture surface of the tested specimens subjected to vibration + cyclic loading have shown higher presence of brittle phases such as martensite (in the form of isolated planar facets) and secondary micro cracks. This could be the reason for the reduction of fatigue life in pipe subjected to vibration + cyclic loading. - Highlights: → Vibration loading affects fatigue crack growth rate. → Crack initiation life depends on crack tip radius. → Crack initiation life depends on the characteristic distance. → Characteristic distance depends on the loading conditions. → Vibration + cyclic load gives lower fatigue life.

  15. Modeling and Analysis of a Combined Stress-Vibration Fiber Bragg Grating Sensor. (United States)

    Yao, Kun; Lin, Qijing; Jiang, Zhuangde; Zhao, Na; Tian, Bian; Shi, Peng; Peng, Gang-Ding


    A combined stress-vibration sensor was developed to measure stress and vibration simultaneously based on fiber Bragg grating (FBG) technology. The sensor is composed of two FBGs and a stainless steel plate with a special design. The two FBGs sense vibration and stress and the sensor can realize temperature compensation by itself. The stainless steel plate can significantly increase sensitivity of vibration measurement. Theoretical analysis and Finite Element Method (FEM) were used to analyze the sensor's working mechanism. As demonstrated with analysis, the obtained sensor has working range of 0-6000 Hz for vibration sensing and 0-100 MPa for stress sensing, respectively. The corresponding sensitivity for vibration is 0.46 pm/g and the resulted stress sensitivity is 5.94 pm/MPa, while the nonlinearity error for vibration and stress measurement is 0.77% and 1.02%, respectively. Compared to general FBGs, the vibration sensitivity of this sensor is 26.2 times higher. Therefore, the developed sensor can be used to concurrently detect vibration and stress. As this sensor has height of 1 mm and weight of 1.15 g, it is beneficial for minimization and integration.

  16. Analysis of micro vibration in gas film of aerostatic guide way based on molecule collision theory

    Directory of Open Access Journals (Sweden)

    Yang Shao Hua


    Full Text Available Micro vibration of the aerostatic guide way has a significant impact on its dynamic characteristics and stability, which limits the development of pneumatic component. High pressure gas molecules have been collided with the supporting surface and the internal surface of the throttle during the flow process. Variable impulse of the surfaces aside for the gas film are affected by the changes of impulse which formed irregular impact force in horizontal and vertical direction. Micro-vibration takes place based on the natural frequency of the system and its frequency doubling. In this paper, the vibration model was established to describe the dynamic characteristics of the gas film, and the formation mechanism of micro vibration in the film is defined. Through the simulation analysis and experimental comparison, formation mechanism of the micro vibration in the gas film is confirmed. It was proposed that the micro vibration of gas film can be produced no matter whether there is a gas chamber or not in the throttle. Under the same conditions, the micro vibration of the guide way with air chamber is greater than that without any chamber. The frequency points of the vibration peaks are almost the same, as well as the vibration pattern in the frequency domain.

  17. Vibrational properties of amorphous semiconductors

    International Nuclear Information System (INIS)

    Schulz, P.A.B.


    A model for the lattice dynamics of a-Si 1-X N X is introduced. This model is based on a Born hamiltonian, solved in the Bethe lattice approximation. Starting from the local density of vibrational states, we analize the infrared absoption spectra of this material. (author) [pt

  18. Ultrafast vibrations of gold nanorings

    DEFF Research Database (Denmark)

    Kelf, T; Tanaka, Y; Matsuda, O


    We investigate the vibrational modes of gold nanorings on a silica substrate with an ultrafast optical technique. By comparison with numerical simulations, we identify several resonances in the gigahertz range associated with axially symmetric deformations of the nanoring and substrate. We...

  19. Monothiodibenzoylmethane: Structural and vibrational assignments

    DEFF Research Database (Denmark)

    Hansen, Bjarke Knud Vilster; Gorski, Alexander; Posokhov, Yevgen


    vibrational spectra were compared with theoretical transitions obtained with B3LYP/cc-pVTZ density functional theory (DFT). The results leave no doubt that the stable ground state configuration of TDBM corresponds to the intramolecularly hydrogen bonded enol form (e-CCC), and that the photoproduct corresponds...

  20. Low-Vibration Oscillating Compressor (United States)

    Studer, P. A.


    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.

  1. Vibrational relaxation in OCS mixtures

    International Nuclear Information System (INIS)

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


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

  2. Ultrafast vibrations of gold nanorings

    DEFF Research Database (Denmark)

    Kelf, T; Tanaka, Y; Matsuda, O


    We investigate the vibrational modes of gold nanorings on a silica substrate with an ultrafast optical technique. By comparison with numerical simulations, we identify several resonances in the gigahertz range associated with axially symmetric deformations of the nanoring and substrate. We elucid...

  3. 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


    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.

  4. Tensor-decomposed vibrational coupled-cluster theory: Enabling large-scale, highly accurate vibrational-structure calculations (United States)

    Madsen, Niels Kristian; Godtliebsen, Ian H.; Losilla, Sergio A.; Christiansen, Ove


    A new implementation of vibrational coupled-cluster (VCC) theory is presented, where all amplitude tensors are represented in the canonical polyadic (CP) format. The CP-VCC algorithm solves the non-linear VCC equations without ever constructing the amplitudes or error vectors in full dimension but still formally includes the full parameter space of the VCC[n] model in question resulting in the same vibrational energies as the conventional method. In a previous publication, we have described the non-linear-equation solver for CP-VCC calculations. In this work, we discuss the general algorithm for evaluating VCC error vectors in CP format including the rank-reduction methods used during the summation of the many terms in the VCC amplitude equations. Benchmark calculations for studying the computational scaling and memory usage of the CP-VCC algorithm are performed on a set of molecules including thiadiazole and an array of polycyclic aromatic hydrocarbons. The results show that the reduced scaling and memory requirements of the CP-VCC algorithm allows for performing high-order VCC calculations on systems with up to 66 vibrational modes (anthracene), which indeed are not possible using the conventional VCC method. This paves the way for obtaining highly accurate vibrational spectra and properties of larger molecules.

  5. Distributed Fiber-Optic Sensors for Vibration Detection. (United States)

    Liu, Xin; Jin, Baoquan; Bai, Qing; Wang, Yu; Wang, Dong; Wang, Yuncai


    Distributed fiber-optic vibration sensors receive extensive investigation and play a significant role in the sensor panorama. Optical parameters such as light intensity, phase, polarization state, or light frequency will change when external vibration is applied on the sensing fiber. In this paper, various technologies of distributed fiber-optic vibration sensing are reviewed, from interferometric sensing technology, such as Sagnac, Mach-Zehnder, and Michelson, to backscattering-based sensing technology, such as phase-sensitive optical time domain reflectometer, polarization-optical time domain reflectometer, optical frequency domain reflectometer, as well as some combinations of interferometric and backscattering-based techniques. Their operation principles are presented and recent research efforts are also included. Finally, the applications of distributed fiber-optic vibration sensors are summarized, which mainly include structural health monitoring and perimeter security, etc. Overall, distributed fiber-optic vibration sensors possess the advantages of large-scale monitoring, good concealment, excellent flexibility, and immunity to electromagnetic interference, and thus show considerable potential for a variety of practical applications.

  6. Potassium-cobalt sulphate crystal growth assisted by low frequency vibrations (United States)

    Sadovsky, A.; Ermochenkov, I.; Dubovenko, E.; Sukhanova, E.; Bebyakin, M.; Dubov, V.; Avetissov, I.


    Single crystals of K2Co(SO4)2·6H2O were grown from solution using the temperature reduction method enhanced by the axial low frequency vibration control technique (AVC-technique). Physical modeling of heat-mass transfer in solution under the AVC action was performed. The growth rate of the AVC grown crystal was found to be twice that of the crystal grown under natural convection conditions. Analysis of spectral characteristics (absorption and Raman spectra) as well as structural properties (dislocation density and microhardness) of the grown crystals showed the significant superiority of the AVC technique for the growth of K2Co(SO4)2·6H2O crystals.

  7. An Efficient Modal Control Strategy for the Active Vibration Control of a Truss Structure

    Directory of Open Access Journals (Sweden)

    Ricardo Carvalhal


    Full Text Available In this paper an efficient modal control strategy is described for the active vibration control of a truss structure. In this approach, a feedback force is applied to each mode to be controlled according to a weighting factor that is determined by assessing how much each mode is excited by the primary source. The strategy is effective provided that the primary source is at a fixed position on the structure, and that the source is stationary in the statistical sense. To test the effectiveness of the control strategy it is compared with an alternative, established approach namely, Independent Modal Space Control (IMSC. Numerical simulations show that with the new strategy it is possible to significantly reduce the control effort required, with a minimal reduction in control performance.

  8. Reduction corporoplasty. (United States)

    Hakky, Tariq S; Martinez, Daniel; Yang, Christopher; Carrion, Rafael E


    Here we present the first video demonstration of reduction corporoplasty in the management of phallic disfigurement in a 17 year old man with a history sickle cell disease and priapism. Surgical management of aneurysmal dilation of the corpora has yet to be defined in the literature. We preformed bilateral elliptical incisions over the lateral corpora as management of aneurysmal dilation of the corpora to correct phallic disfigurement. The patient tolerated the procedure well and has resolution of his corporal disfigurement. Reduction corporoplasty using bilateral lateral elliptical incisions in the management of aneurysmal dilation of the corpora is a safe an feasible operation in the management of phallic disfigurement.

  9. Time-domain prefilter design for enhanced tracking and vibration suppression in machine motion control (United States)

    Cole, Matthew O. T.; Shinonawanik, Praween; Wongratanaphisan, Theeraphong


    Structural flexibility can impact negatively on machine motion control systems by causing unmeasured positioning errors and vibration at locations where accurate motion is important for task execution. To compensate for these effects, command signal prefiltering may be applied. In this paper, a new FIR prefilter design method is described that combines finite-time vibration cancellation with dynamic compensation properties. The time-domain formulation exploits the relation between tracking error and the moment values of the prefilter impulse response function. Optimal design solutions for filters having minimum H2 norm are derived and evaluated. The control approach does not require additional actuation or sensing and can be effective even without complete and accurate models of the machine dynamics. Results from implementation and testing on an experimental high-speed manipulator having a Delta robot architecture with directionally compliant end-effector are presented. The results show the importance of prefilter moment values for tracking performance and confirm that the proposed method can achieve significant reductions in both peak and RMS tracking error, as well as settling time, for complex motion patterns.

  10. Design of lightweight magnesium car body structure under crash and vibration constraints

    Directory of Open Access Journals (Sweden)

    Morteza Kiani


    Full Text Available Car body design in view of structural performance and lightweighting is a challenging task due to all the performance targets that must be satisfied such as vehicle safety and ride quality. In this paper, material replacement along with multidisciplinary design optimization strategy is proposed to develop a lightweight car body structure that satisfies the crash and vibration criteria while minimizing weight. Through finite element simulations, full frontal, offset frontal, and side crashes of a full car model are evaluated for peak acceleration, intrusion distance, and the internal energy absorbed by the structural parts. In addition, the first three fundamental natural frequencies are combined with the crash metrics to form the design constraints. The wall thicknesses of twenty-two parts are considered as the design variables. Latin Hypercube Sampling is used to sample the design space, while Radial Basis Function methodology is used to develop surrogate models for the selected crash responses at multiple sites as well as the first three fundamental natural frequencies. A nonlinear surrogate-based optimization problem is formulated for mass minimization under crash and vibration constraints. Using Sequential Quadratic Programming, the design optimization problem is solved with the results verified by finite element simulations. The performance of the optimum design with magnesium parts shows significant weight reduction and better performance compared to the baseline design.

  11. Task-specific recruitment of motor units for vibration damping. (United States)

    Wakeling, James M; Liphardt, Anna-Maria


    Vibrations occur within the soft tissues of the lower extremities due to the heel-strike impact during walking. Increases in muscle activity in the lower extremities result in increased damping to reduce this vibration. The myoelectric intensity spectra were compared using principal component analysis from the tibialis anterior and lateral gastrocnemius of 40 subjects walking with different shoe conditions. The soft insert condition resulted in a significant, simultaneous increase in muscle activity with a shift to higher myoelectric frequencies in the period 0-60 ms after heel-strike which is the period when the greater vibration damping occurred. These increases in myoelectric frequency match the spectral patterns which indicate increases in recruitment of faster motor units. It is concluded that fast motor units are recruited during the task of damping the soft-tissue resonance that occurs following heel-strike.

  12. Effect on the vibration of the suspension system

    Directory of Open Access Journals (Sweden)

    L. Dahil


    Full Text Available In order to determine the damping effect of shock absorbs in vehicles, different vehicles acceleration values were measured while they were passing over speed bumps at different speeds. The vehicles’ vibration magnitudes caused by road roughness were analyzed. In this study the measurements were conducted with two different vehicles, multiple drivers and at different speeds. The vibration valves were determined with a HVM 100 device, in different field conditions and at 20 - 40 and 60 km/h by transferring the results to the system. According to the results of statistical analysis damping effect of the shock absorbers in the vehicles changed in different speed ranges and field conditions and it was seen that driver’s performance was significantly affected due to the vibration.

  13. Electromagnetic Vibration Energy Harvesting Devices Architectures, Design, Modeling and Optimization

    CERN Document Server

    Spreemann, Dirk


    Electromagnetic vibration transducers are seen as an effective way of harvesting ambient energy for the supply of sensor monitoring systems. Different electromagnetic coupling architectures have been employed but no comprehensive comparison with respect to their output performance has been carried out up to now. Electromagnetic Vibration Energy Harvesting Devices introduces an optimization approach which is applied to determine optimal dimensions of the components (magnet, coil and back iron). Eight different commonly applied coupling architectures are investigated. The results show that correct dimensions are of great significance for maximizing the efficiency of the energy conversion. A comparison yields the architectures with the best output performance capability which should be preferably employed in applications. A prototype development is used to demonstrate how the optimization calculations can be integrated into the design–flow. Electromagnetic Vibration Energy Harvesting Devices targets the design...

  14. Intelligent vibration control of ELTs and large AO hardware (United States)

    Pott, J.-U.; Kürster, M.; Trowitzsch, J.; Borelli, J.; Rohloff, R.-R.; Herbst, T.; Böhm, M.; Keck, A.; Ruppel, T.; Sawodny, O.


    MPIA leads the construction of the LINC-NIRVANA instrument, the MCAO-supported Fizeau imager for the LBT, serves as pathfinder for future ELT-AO imagers in terms of size and technology. In this contribution, we review recent results and significant progress made on the development of key items of our stratgey to achieve a piston stability of up to 100nm during a science exposure. We present an overview of our vibration control strategies for optical path and tip-tilt stabilization, involving accelerometer based real-time vibration measurements, vibration sensitive active control of actuators, and the development of a dynamical model of the LBT. MPIA also co-develops the E-ELT first-light NIR imager MICADO (both SCAO and MCAO assisted). Our experiences, made with LINC-NIRVANA, will be fed into the MICADO structural AO design to reach highest on-sky sensitivity.

  15. Smart helicopter rotors optimization and piezoelectric vibration control

    CERN Document Server

    Ganguli, Ranjan; Viswamurthy, Sathyamangalam Ramanarayanan


    Exploiting the properties of piezoelectric materials to minimize vibration in rotor-blade actuators, this book demonstrates the potential of smart helicopter rotors to achieve the smoothness of ride associated with jet-engined, fixed-wing aircraft. Vibration control is effected using the concepts of trailing-edge flaps and active-twist. The authors’ optimization-based approach shows the advantage of multiple trailing-edge flaps and algorithms for full-authority control of dual trailing-edge-flap actuators are presented. Hysteresis nonlinearity in piezoelectric stack actuators is highlighted and compensated by use of another algorithm. The idea of response surfaces provides for optimal placement of trailing-edge flaps. The concept of active twist involves the employment of piezoelectrically induced shear actuation in rotating beams. Shear is then demonstrated for a thin-walled aerofoil-section rotor blade under feedback-control vibration minimization. Active twist is shown to be significant in reducing vibra...

  16. An analytical study of the effects of transverse shear deformation and anisotropy on natural vibration frequencies of laminated cylinders (United States)

    Jegley, Dawn C.


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

  17. Vibration produced by hand-held olive electrical harvesters

    Directory of Open Access Journals (Sweden)

    Emanuele Cerruto


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

  18. Vibrational dynamics (IR, Raman, NRVS) and DFT study of new antitumor tetranuclearstannoxanecluster, Sn(IV)$-$oxo$-${di$-$o$-$vanillin} dimethyl dichloride

    Energy Technology Data Exchange (ETDEWEB)

    Arjmand, F. [Aligarh Muslim Univ., Aligarh (India). Dept. of Chemistry; Sharma, S. [Aligarh Muslim Univ., Aligarh (India). Dept. of Chemistry; Usman, M. [Aligarh Muslim Univ., Aligarh (India). Dept. of Chemistry; Leu, B. M. [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Hu, M. Y. [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Toupet, L. [Univ. de Rennes, Rennes (France). Inst. de Physique de Rennes; Gosztola, David J. [Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials; Tabassum, S. [Aligarh Muslim Univ., Aligarh (India). Dept. of Chemistry


    The vibrational dynamics of a newly synthesized tetrastannoxane was characterized with a combination of experimental (Raman, IR and tin-based nuclear resonance vibrational spectroscopy) and computational (DFT/B3LYP) methods, with an emphasis on the vibrations of the tin sites. The cytotoxic activity revealed a significant regression selectively against the human pancreatic cell lines.

  19. Periodontal tissue activation by vibration: intermittent stimulation by resonance vibration accelerates experimental tooth movement in rats. (United States)

    Nishimura, Makoto; Chiba, Mirei; Ohashi, Toshiro; Sato, Masaaki; Shimizu, Yoshiyuki; Igarashi, Kaoru; Mitani, Hideo


    Accelerating the speed of orthodontic tooth movement should contribute to the shortening of the treatment period. This would be beneficial because long treatment times are a negative aspect of orthodontic treatment. In this study, we evaluated the effects of mechanical stimulation by resonance vibration on tooth movement, and we showed the cellular and molecular mechanisms of periodontal ligament responses. The maxillary first molars of 6-week-old male Wistar rats were moved to the buccal side by using an expansive spring for 21 days (n = 6, control group), and the amount of tooth movement was measured. Additional vibrational stimulation (60 Hz, 1.0 m/s(2)) was applied to the first molars by using a loading vibration system for 8 minutes on days 0, 7, and 14 during orthodontic tooth movement (n = 6, experimental group). The animals were killed under anesthesia, and each maxilla was dissected. The specimens were fixed, decalcified, and embedded in paraffin. Sections were used for immunohistochemical analysis of receptor activator of NF kappa B ligand (RANKL) expression. The number of osteoclasts in the alveolar bone was counted by using TRAP staining, and the amount of root resorption was measured in sections stained with hematoxylin and eosin. The average resonance frequency of the maxillary first molar was 61.02 +/- 8.38 Hz. Tooth movement in the experimental group was significantly greater than in the control group (P vibration might accelerate orthodontic tooth movement via enhanced RANKL expression in the periodontal ligament without additional damage to periodontal tissues such as root resorption.

  20. Experience in WWER fuel assemblies vibration analysis

    International Nuclear Information System (INIS)

    Ovtcharov, O.; Pavelko, V.; Usanov, A.; Arkadov, G.; Dolgov, A.; Molchanov, V.


    It is stated that the vibration studies of internals and the fuel assemblies should be conducted during the reactor designing, commissioning and commercial operation stages and the analysis methods being used should complement each other. The present paper describes the methods and main results of the vibration noise studies of internals and the fuel assemblies of the operating NPPs with WWER reactors, as an example of the implementation of the comprehensive approach to the analysis on equipment flow-induced vibration. At that, the characteristics of internals and fuel assemblies vibration loading were dealt jointly as they are elements of the same compound oscillating system and their vibrations have the interrelated nature

  1. Vibration isolation of a ship's seat (United States)

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


    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.

  2. 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


    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.

  3. Prevalent hallucinations during medical internships: phantom vibration and ringing syndromes.

    Directory of Open Access Journals (Sweden)

    Yu-Hsuan Lin

    Full Text Available BACKGROUND: Phantom vibration syndrome is a type of hallucination reported among mobile phone users in the general population. Another similar perception, phantom ringing syndrome, has not been previously described in the medical literature. METHODS: A prospective longitudinal study of 74 medical interns (46 males, 28 females; mean age, 24.8±1.2 years was conducted using repeated investigations of the prevalence and associated factors of phantom vibration and ringing. The accompanying symptoms of anxiety and depression were evaluated with the Beck Anxiety and Depression Inventories before the internship began, and again at the third, sixth, and twelfth internship months, and two weeks after the internship ended. RESULTS: The baseline prevalence of phantom vibration was 78.1%, which increased to 95.9% and 93.2% in the third and sixth internship months. The prevalence returned to 80.8% at the twelfth month and decreased to 50.0% 2 weeks after the internship ended. The baseline prevalence of phantom ringing was 27.4%, which increased to 84.9%, 87.7%, and 86.3% in the third, sixth, and twelfth internship months, respectively. This returned to 54.2% two weeks after the internship ended. The anxiety and depression scores also increased during the internship, and returned to baseline two weeks after the internship. There was no significant correlation between phantom vibration/ringing and symptoms of anxiety or depression. The incidence of both phantom vibration and ringing syndromes significantly increased during the internship, and subsequent recovery. CONCLUSION: This study suggests that phantom vibration and ringing might be entities that are independent of anxiety or depression during evaluation of stress-associated experiences during medical internships.

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

    Directory of Open Access Journals (Sweden)

    Masatoshi eKasagi


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

  5. Determination of rheological properties of fresh concrete and similar materials in a vibration rheometer

    Directory of Open Access Journals (Sweden)

    Sandra Juradin


    Full Text Available A vibration rheometer has been developed for the purpose of determining the viscosity coefficient and the yield value of fresh concrete under vibration. The main parts of the apparatus, a test specimen and a vibration source form a unitary oscillatory system whose parameters can be measured with sufficient precision. Two types of fine grained reference material have been prepared and examined; one with a high coefficient of viscosity and the other with a high yield value. The rheological properties of reference materials have been determined in a capillary tube viscometer. Since there is no analytical solution to the flow in the vibration rheometer, the constants of the vibration rheometer have been determined by experiment, for each position of the apparatus piston within the measuring range. The parameters of the flow depend on the maximum acceleration of the vibration source. An increase in acceleration causes an increase in the yield value as well as a reduction in the plastic viscosity coefficient of the material specimen. A testing of fresh mortar has been carried out as well. The obtained results have been compared with the impact on reference materials, which makes the results of our research applicable to fresh vibrated concrete.

  6. An adjoint method of sensitivity analysis for residual vibrations of structures subject to impacts (United States)

    Yan, Kun; Cheng, Gengdong


    For structures subject to impact loads, the residual vibration reduction is more and more important as the machines become faster and lighter. An efficient sensitivity analysis of residual vibration with respect to structural or operational parameters is indispensable for using a gradient based optimization algorithm, which reduces the residual vibration in either active or passive way. In this paper, an integrated quadratic performance index is used as the measure of the residual vibration, since it globally measures the residual vibration response and its calculation can be simplified greatly with Lyapunov equation. Several sensitivity analysis approaches for performance index were developed based on the assumption that the initial excitations of residual vibration were given and independent of structural design. Since the resulting excitations by the impact load often depend on structural design, this paper aims to propose a new efficient sensitivity analysis method for residual vibration of structures subject to impacts to consider the dependence. The new method is developed by combining two existing methods and using adjoint variable approach. Three numerical examples are carried out and demonstrate the accuracy of the proposed method. The numerical results show that the dependence of initial excitations on structural design variables may strongly affects the accuracy of sensitivities.

  7. Control of pipe vibrations; Schwingungsminderung bei Rohrleitungen

    Energy Technology Data Exchange (ETDEWEB)

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


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

  8. Interfacial instabilities in vibrated fluids (United States)

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


    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

  9. Vibrational collapse of boroxol rings in compacted B2O3 glasses: a study of Raman scattering and low temperature specific heat (United States)

    Carini, Giovanni, Jr.; Carini, Giuseppe; D’Angelo, Giovanna; Federico, Mauro; Romano, Valentino


    Low and high frequency Raman scattering of B2O3 glasses, compacted under GPa pressures, has been performed to investigate structural changes due to increasing atomic packing. Compacted glasses, annealed at ambient temperature and pressure, experience a time-dependent decrease of the density to a smaller constant value over a period of few months, displaying a permanent plastic deformation. Increasing densification determines a parallel and progressive decrease of the intensity of the Boson peak and the main band at 808 cm‑1, both these modes arising from localized vibrations involving planar boroxol rings (B3O6), the glassy units formed from three basic BO3 triangles. The 808 cm‑1 mode preserves its frequency, while the BP evidences a well-defined frequency increase. The high-frequency multicomponent band between 1200 and 1600 cm‑1 also changes with increasing densification, disclosing a decreasing intensity of the 1260 cm‑1 mode due to oxygen vibrations of BO3 units bridging boroxol rings. This indicates the gradual vibrational collapse of groups formed from rings connected by more complex links than a single bridging oxygen. The observed behaviours suggest that glass compaction causes severe deformation of boroxol rings, determining a decrease of groups which preserve unaltered their vibrational activity. Growing glass densification stiffens the network and leads to a decrease of the excess heat capacity over the Debye prediction below 20 K, which is not accounted for by the hardening of the elastic continuum. By using the low-frequency Raman scattering to determine the temperature dependence of the heat capacity, it has been evaluated the density of low-frequency vibrational states which discloses a significant reduction of excess modes with increasing density.

  10. Study on the vibrational scraping of uranium product from a solid cathode of electrorefiner

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Bin; Kang, Young Ho; Hwang, Sung Chan; Lee, Han Soo; Paek, Seung Woo; Ahn, Do Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    A high-throughput electrorefiner has been developed for commercialization use by enhancing the uranium recovery from the reduced metal which is produced from the oxide reduction process. It is necessary to scrap and effectively collect uranium dendrites from the surface of the solid cathode for high yield. When a steel electrode is used as the cathode in the electrorefining process, uranium is deposited and regularly stuck to the steel cathode during electrorefining. The sticking coefficient of a steel cathode is very high. In order to decrease the sticking coefficient of the steel cathode effectively, vibration mode was applied to the electrode in this study. Uranium dendrites were scraped and fell apart from the steel cathode by a vibration force. The vibrational scraping of the steel cathode was compared to the self-scraping of the graphite cathode. Effects of the applied current density and the vibration stroke on the scraping of the uranium dendrites were also investigated.

  11. Vibration tests on single heat exchanger tubes in air and static water

    International Nuclear Information System (INIS)

    Collinson, A.E.; Warneford, I.P.


    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)

  12. Attitudes Toward, and Use of, Vibrators in China. (United States)

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


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

  13. Two-phase flow induced vibrations in CANDU steam generators

    International Nuclear Information System (INIS)

    Gidi, A.


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

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

    International Nuclear Information System (INIS)

    Prisecaru, Ilie; Serban, Viorel; Sandrea Madalina


    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

  15. Effect of Vibration on Pain Response to Heel Lance: A Pilot Randomized Control Trial. (United States)

    McGinnis, Kate; Murray, Eileen; Cherven, Brooke; McCracken, Courtney; Travers, Curtis


    Applied mechanical vibration in pediatric and adult populations has been shown to be an effective analgesic for acute and chronic pain, including needle pain. Studies among the neonatal population are lacking. According to the Gate Control Theory, it is expected that applied mechanical vibration will have a summative effect with standard nonpharmacologic pain control strategies, reducing behavioral and physiologic pain responses to heel lancing. To determine the safety and efficacy of mechanical vibration for relief of heel lance pain among neonates. In this parallel design randomized controlled trial, eligible enrolled term or term-corrected neonates (n = 56) in a level IV neonatal intensive care unit were randomized to receive either sucrose and swaddling or sucrose, swaddling, and vibration for heel lance analgesia. Vibration was applied using a handheld battery-powered vibrator (Norco MiniVibrator, Hz = 92) to the lateral aspect of the lower leg along the sural dermatome throughout the heel lance procedure. Neonatal Pain, Agitation, and Sedation Scale (N-PASS) scores, heart rate, and oxygen saturations were collected at defined intervals surrounding heel lancing. Infants in the vibration group (n = 30) had significantly lower N-PASS scores and more stable heart rates during heel stick (P = .006, P = .037) and 2 minutes after heel lance (P = .002, P = .016) than those in the nonvibration group. There were no adverse behavioral or physiologic responses to applied vibration in the sample. Applied mechanical vibration is a safe and effective method for managing heel lance pain. This pilot study suggests that mechanical vibration warrants further exploration as a nonpharmacologic pain management tool among the neonatal population.

  16. The effects of an inserted linear carbon chain on the vibration of a carbon nanotube

    International Nuclear Information System (INIS)

    Hu, Z L; Guo, X M; Ru, C Q


    An elastic string-elastic shell model is developed to study the coupled vibration of a carbon nanowire made of a linear carbon chain (C-chain) inserted inside a carbon nanotube (CNT). It is shown that the vibration of the inserted C-chain is coupled with vibration of the CNT only for vibration modes with circumferential wavenumber n = 1. In other cases, such as axisymmetric modes (n = 0) or higher-order vibration modes with n≥2, total resultant van der Waals (vdW) force acting on the C-chain due to the innermost tube always vanishes, and therefore vibration of the CNT does not cause vibration of the inserted C-chain, although the existence of the C-chain does have an effect on the vibration of the CNT through the chain-CNT vdW forces acting on the innermost tube. The present model predicts that non-coaxial vibration between the C-chain and the innermost tube does not occur due to negligible bending rigidity of the C-chain. In addition, it is found that the C-chain has most significant effect on the lowest frequency associated with the radial vibration mode for circumferential wavenumber 2 (n = 2). In particular, the effect of the C-chain on the axisymmetric radial breathing frequencies (n = 0) predicted by the present model is found to be in reasonable agreement with known experimental and modeling results available in the literature. The present work offers systematic modeling results on the effects of an inserted C-chain on the vibration of CNTs

  17. Dynamical response of vibrating ferromagnets

    CERN Document Server

    Gaganidze, E; Ziese, M


    The resonance frequency of vibrating ferromagnetic reeds in a homogeneous magnetic field can be substantially modified by intrinsic and extrinsic field-related contributions. Searching for the physical reasons of the field-induced resonance frequency change and to study the influence of the spin glass state on it, we have measured the low-temperature magnetoelastic behavior and the dynamical response of vibrating amorphous and polycrystalline ferromagnetic ribbons. We show that the magnetoelastic properties depend strongly on the direction of the applied magnetic field. The influence of the re-entrant spin glass transition on these properties is discussed. We present clear experimental evidence that for applied fields perpendicular to the main area of the samples the behavior of ferromagnetic reeds is rather independent of the material composition and magnetic state, exhibiting a large decrease of the resonance frequency. This effect can be very well explained with a model based on the dynamical response of t...

  18. A night with good vibrations

    CERN Multimedia


    Next week-end, the Geneva Science History Museum invites you to a Science Night under the banner of waves and vibrations. Scientists, artists and storytellers from more than forty institutes and local or regional associations will show that waves and vibrations form an integral part of our environment. You will be able to get in contact with the nature of waves through interactive exhibitions on sound and light and through hands-on demonstrations arranged in the Park of the Perle du Lac. On the CERN stand, you will be able to measure the speed of light with a bar of chocolate, and understand the scattering of waves with plastic ducks. Amazing, no? In addition to the stands, the Night will offer many other activities: reconstructions of experiments, a play, a concert of crystal glasses, an illuminated fountain, a house of spirits. More information Science Night, 6 and 7 July, Park of the Perle du Lac, Geneva

  19. Reduction Corporoplasty

    Directory of Open Access Journals (Sweden)

    Tariq S. Hakky


    Full Text Available Objective Here we present the first video demonstration of reduction corporoplasty in the management of phallic disfigurement in a 17 year old man with a history sickle cell disease and priapism. Introduction Surgical management of aneurysmal dilation of the corpora has yet to be defined in the literature. Materials and Methods: We preformed bilateral elliptical incisions over the lateral corpora as management of aneurysmal dilation of the corpora to correct phallic disfigurement. Results The patient tolerated the procedure well and has resolution of his corporal disfigurement. Conclusions Reduction corporoplasty using bilateral lateral elliptical incisions in the management of aneurysmal dilation of the corpora is a safe an feasible operation in the management of phallic disfigurement.

  20. The effect of inclined soil layers on surface vibration from underground railways using a semi-analytical approach

    International Nuclear Information System (INIS)

    Jones, S; Hunt, H


    Ground vibration due to underground railways is a significant source of disturbance for people living or working near the subways. The numerical models used to predict vibration levels have inherent uncertainty which must be understood to give confidence in the predictions. A semi-analytical approach is developed herein to investigate the effect of soil layering on the surface vibration of a halfspace where both soil properties and layer inclination angles are varied. The study suggests that both material properties and inclination angle of the layers have significant effect (± 10dB) on the surface vibration response.

  1. Vibrational communication of subterranean rodents




    This PhD. thesis focuses on the vibrational communication of subterranean mammals, in particular, vocal communication of bathyergids (Heliophobius argenteocinereus, Fukomys mechowii, Fukomys darlingi) and seismic communication of Tachyoryctes. We recorded and analyzed the vocalization of three species and discussed the physical parameters of their vocalization in relationship to the special underground acoustic environment. Moreover, social systems of African mole-rats range from solitary to ...

  2. Surveillance of vibrations in PWR

    International Nuclear Information System (INIS)

    Espefaelt, R.; Lorenzen, J.; Aakerhielm, F.


    The core of a PWR - including fuel elements, internal structure, control rods and core support structure inside the pressure vessel - is subjected to forces which can cause vibrations. One sensitive means to detect and analyse such vibrations is by means of the noise from incore and excore neutron detector signals. In this project noise recordings have been made on two occasions in the Ringhals 2 plant and the obtained data been analysed using the Studsvik Noise Analysis Program System (SNAPS). The results have been intepreted and a detailed description of the vibrational status of the core and pressure vessel internals has been produced. On the basis of the obtained results it is proposed that neutron signal noise analysis should be performed at each PWR plant in the beginning, middle and end of each fuel cycle and an analysis be made using the methods developed in the project. It would also provide a contribution to a higher degree of preparedness for diagnostic tasks in case of unexpected and abnormal events. (author)

  3. Effect of electromagnetic vibration on the microstructure of direct chill cast Al-Zn-Mg-Cu alloy

    International Nuclear Information System (INIS)

    Zuo, Y; Fu, X; Zhu, Q; Li, L; Wang, P; Cui, J


    An electromagnetic vibration was achieved by the combined application of an alternating magnetic field and a stationary magnetic field during direct chill (DC) casting process. The ingots with 200 mm in diameter were prepared under the influence of electromagnetic vibration. The effect of electromagnetic vibration on the microstructure of an Al-Zn-Mg-Cu alloy was studied. The results showed that electromagnetic vibration has a significant effect on the solidification behaviour, under the influence of electromagnetic vibration during DC casting process, the microstructure is significantly refined and the uniformity of microstructure is evidently improved. This paper introduces the DC casting technology with the application of electromagnetic vibration, presents these results and gives corresponding discussions. (paper)

  4. Dissipation enhanced vibrational sensing in an olfactory molecular switch

    International Nuclear Information System (INIS)

    Chęcińska, Agata; Heaney, Libby; Pollock, Felix A.; Nazir, Ahsan


    Motivated by a proposed olfactory mechanism based on a vibrationally activated molecular switch, we study electron transport within a donor-acceptor pair that is coupled to a vibrational mode and embedded in a surrounding environment. We derive a polaron master equation with which we study the dynamics of both the electronic and vibrational degrees of freedom beyond previously employed semiclassical (Marcus-Jortner) rate analyses. We show (i) that in the absence of explicit dissipation of the vibrational mode, the semiclassical approach is generally unable to capture the dynamics predicted by our master equation due to both its assumption of one-way (exponential) electron transfer from donor to acceptor and its neglect of the spectral details of the environment; (ii) that by additionally allowing strong dissipation to act on the odorant vibrational mode, we can recover exponential electron transfer, though typically at a rate that differs from that given by the Marcus-Jortner expression; (iii) that the ability of the molecular switch to discriminate between the presence and absence of the odorant, and its sensitivity to the odorant vibrational frequency, is enhanced significantly in this strong dissipation regime, when compared to the case without mode dissipation; and (iv) that details of the environment absent from previous Marcus-Jortner analyses can also dramatically alter the sensitivity of the molecular switch, in particular, allowing its frequency resolution to be improved. Our results thus demonstrate the constructive role dissipation can play in facilitating sensitive and selective operation in molecular switch devices, as well as the inadequacy of semiclassical rate equations in analysing such behaviour over a wide range of parameters

  5. Flow induced vibrations of the CLIC X-Band accelerating structures

    CERN Document Server

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


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

  6. A Numerical Study on the Screening of Blast-Induced Waves for Reducing Ground Vibration (United States)

    Park, Dohyun; Jeon, Byungkyu; Jeon, Seokwon


    Blasting is often a necessary part of mining and construction operations, and is the most cost-effective way to break rock, but blasting generates both noise and ground vibration. In urban areas, noise and vibration have an environmental impact, and cause structural damage to nearby structures. Various wave-screening methods have been used for many years to reduce blast-induced ground vibration. However, these methods have not been quantitatively studied for their reduction effect of ground vibration. The present study focused on the quantitative assessment of the effectiveness in vibration reduction of line-drilling as a screening method using a numerical method. Two numerical methods were used to analyze the reduction effect toward ground vibration, namely, the “distinct element method” and the “non-linear hydrocode.” The distinct element method, by particle flow code in two dimensions (PFC 2D), was used for two-dimensional parametric analyses, and some cases of two-dimensional analyses were analyzed three-dimensionally using AUTODYN 3D, the program of the non-linear hydrocode. To analyze the screening effectiveness of line-drilling, parametric analyses were carried out under various conditions, with the spacing, diameter of drill holes, distance between the blasthole and line-drilling, and the number of rows of drill holes, including their arrangement, used as parameters. The screening effectiveness was assessed via a comparison of the vibration amplitude between cases both with and without screening. Also, the frequency distribution of ground motion of the two cases was investigated through fast Fourier transform (FFT), with the differences also examined. From our study, it was concluded that line-drilling as a screening method of blast-induced waves was considerably effective under certain design conditions. The design details for field application have also been proposed.

  7. Attitudes Toward, and Use of, Vibrators in China


    Jing, S.; Lay, A.; Weis, L.; Furnham, A.


    The current study examined the relationship between traditional masculine traits and attitudes toward vibrator use, actual vibrator use, and frequency of vibrator use in China. In all, 235 Chinese females aged between 16 and 58 years completed a questionnaire regarding attitudes toward, and personal use of, vibrators. The results showed a positive association between masculine traits and attitudes toward women's vibrator use, attitudes toward vibrator use and actual vibrator use, as well as f...

  8. Adaptive Piezoelectric Absorber for Active Vibration Control

    Directory of Open Access Journals (Sweden)

    Sven Herold


    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.

  9. Lightweight Vehicle and Driver’s Whole-Body Models for Vibration Analysis (United States)

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


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

  10. Combined Effects of High-Speed Railway Noise and Ground Vibrations on Annoyance. (United States)

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


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

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

    International Nuclear Information System (INIS)

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


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

  12. Combined isometric and vibration training does not enhance strength beyond that of isometric training alone. (United States)

    Fisher, J; Van-Dongen, M; Sutherland, R


    Research considering combined vibration and strength training is extensive yet results are equivocal. However, to date there appears no research which has considered the combination of both direct vibration and whole-body vibration when used in an isometric deadlift position. The aim of this study was to compare groups performing isometric training with and without direct and whole-body vibration. Twenty four participants (19-24 years) were randomly divided into: isometric training with vibration (ST+VT: N.=8), isometric training without vibration (ST: N.=8), and control (CON: N.=8). Within the training groups participants trained twice per week, for 6 weeks, performing 6-sets of maximal isometric deadlift contractions, increasing in duration from 30 seconds to 40 seconds (weeks 1-6). Hip and knee angle was maintained at 60° and 110°, respectively for both testing and training. Training sessions for ST+VT were identical to ST with the addition of a direct vibratory stimulus through hand-held straps and whole-body vibration via standing on vibration a platform. The amplitude remained constant (2 mm) throughout the intervention whilst the frequency increased from 35Hz to 50Hz. Pre- and post-test isometric strength was measured using an isometric deadlift dynamometer. Results revealed significant increases in isometric strength for both ST+VT (Pstrength training.

  13. Role of correlations of lattice vibrations in channeling

    International Nuclear Information System (INIS)

    Barrett, J.H.; Jackson, D.P.


    Computer simulations of channeling have been done using correlated thermal displacements of the lattice atoms. For the channeling minimum yield and half angles, results are given as a function of temperature. For the surface yield, results are given as a function of angle from the axial direction to supplement earlier results as a function of temperature. In all quantities correlations cause effects qualitatively similar to a reduction in vibration amplitude, although the reduction varies from quantity to quantity. These variations are consistent with the idea that correlations will be most important for a trajectory aligned with the rows and of decreasing importance as the direction of a trajectory approaches a random direction. The largest effect occurs for the surface yield wherein there is a reduction of about 15% for the cases studied so far. (orig.)

  14. Comparing the effects of 3 weeks of upper-body vibration training, vibration and stretching, and stretching alone on shoulder flexibility in college-aged men. (United States)

    Ferguson, Steven L; Kim, Eonho; Seo, Dong-Il; Bemben, Michael G


    This study compared the effects of 3 weeks of upper-body vibration training, vibration and stretching, and stretching alone on shoulder flexibility in college-aged men. Twenty-one men were randomly assigned to vibration-stretching (VS; n = 8), vibration only (VO; n = 6), or stretching only (SO; n = 7) groups that trained 3 times per week for 3 weeks. All 3 groups performed 9 total sets of 30-second stretches. The VS group performed four 30-second upper-body vibration exercises and five 30-second upper-body stretching exercises. The VO group performed nine 30-second upper-body vibration exercises. The SO group performed nine 30-second upper-body stretching exercises. Shoulder flexion (SF), shoulder extension (SE), and shoulder transverse extension (STE) were assessed by a Leighton Flexometer and back scratch tests bilaterally (BSR, BSL) were measured via tape measure. A 1-way analysis of variance (ANOVA) evaluated groups at baseline and a 2-way repeated-measures ANOVA evaluated the interventions over time. At baseline, there were no group differences in age, height, or weight. There was a significant (p alone or combined with stretching, is a viable alternative to a standard stretching routine when attempting to increase shoulder flexibility. Adding vibration training to a flexibility regimen may improve the likelihood of regularly performing flexibility sessions because of increased variety.

  15. Neurocognitive responses to a single session of static squats with whole body vibration. (United States)

    Amonette, William E; Boyle, Mandy; Psarakis, Maria B; Barker, Jennifer; Dupler, Terry L; Ott, Summer D


    The purpose of this study was to determine if the head accelerations using a common whole body vibration (WBV) exercise protocol acutely reduced neurocognition in healthy subjects. Second, we investigated differential responses to WBV plates with 2 different delivery mechanisms: vertical and rotational vibrations. Twelve healthy subjects (N = 12) volunteered and completed a baseline (BASE) neurocognitive assessment: the Immediate Postconcussion Assessment and Cognitive Test (ImPACT). Subjects then participated in 3 randomized exercise sessions separated by no more than 2 weeks. The exercise sessions consisted of five 2-minute sets of static hip-width stance squats, with the knees positioned at a 45° angle of flexion. The squats were performed with no vibration (control [CON]), with a vertically vibrating plate (vertical vibration [VV]), and with a rotational vibrating plate (rotational vibration [RV]) set to 30 Hz with 4 mm of peak-to-peak displacement. The ImPACT assessments were completed immediately after each exercise session and the composite score for 5 cognitive domains was analyzed: verbal memory, visual memory, visual motor speed, reaction time, and impulse control. Verbal memory scores were unaffected by exercise with or without vibration (p = 0.40). Likewise, visual memory was not different (p = 0.14) after CON, VV, or RV. Significant differences were detected for visual motor speed (p = 0.006); VV was elevated compared with BASE (p = 0.01). There were no significant differences (p = 0.26) in reaction time or impulse control (p = 0.16) after exercise with or without vibration. In healthy individuals, 10 minutes of 30 Hz, 4-mm peak-to-peak displacement vibration exposure with a 45° angle of knee flexion did not negatively affect neurocognition.

  16. Vibration analysis on driver’s seat of agricultural tractors during tillage tests

    International Nuclear Information System (INIS)

    Gialamas, T.; Gravalos, I.; Kateris, D.; Xyradakis, P.; Dimitriadis, C.


    The vibration of the driver’s seat of agricultural tractors was investigated during three alternative tillage operations. Three tractors including a range of specifications were considered, at a range of forward speeds. The interactions between the tractors, implements and speeds were examined using the SPSS program and the GLM-ANOVA method. The results analysis indicated that the tractors played the first major role in vibration development in the lateral axis and was followed by the implements. In contrast, the implements played the first major role in the development of vibration in the horizontal axis and are followed by factor tractors. The statistically significant effect in vertical and horizontal axes shows the factor implements. In addition, the statistically significant effect in the vertical and lateral axes shows again the implements to be the most significant factor. Of the implements, the plough shows the highest vibration and displays statistically significant difference in comparison with the other implements.

  17. Vibration analysis on driver’s seat of agricultural tractors during tillage tests

    Energy Technology Data Exchange (ETDEWEB)

    Gialamas, T.; Gravalos, I.; Kateris, D.; Xyradakis, P.; Dimitriadis, C.


    The vibration of the driver’s seat of agricultural tractors was investigated during three alternative tillage operations. Three tractors including a range of specifications were considered, at a range of forward speeds. The interactions between the tractors, implements and speeds were examined using the SPSS program and the GLM-ANOVA method. The results analysis indicated that the tractors played the first major role in vibration development in the lateral axis and was followed by the implements. In contrast, the implements played the first major role in the development of vibration in the horizontal axis and are followed by factor tractors. The statistically significant effect in vertical and horizontal axes shows the factor implements. In addition, the statistically significant effect in the vertical and lateral axes shows again the implements to be the most significant factor. Of the implements, the plough shows the highest vibration and displays statistically significant difference in comparison with the other implements.

  18. Snubber reduction

    International Nuclear Information System (INIS)

    Olson, D.E.; Singh, A.K.


    Many safety-related piping systems in nuclear power plants have been oversupported. Since snubbers make up a large percentage of the pipe supports or restraints used in a plant, a plant's snubber population is much larger than required to adequately restrain the piping. This has resulted in operating problems and unnecessary expenses for maintenance and inservice inspections (ISIs) of snubbers. This paper presents an overview of snubber reduction, including: the incentives for removing snubbers, a historical perspective on how piping became oversupported, why it is possible to remove snubbers, and the costs and benefits of doing so

  19. Vibration measurement with nonlinear converter in the presence of noise (United States)

    Mozuras, Almantas


    Conventional vibration measurement methods use the linear properties of physical converters. These methods are strongly influenced by nonlinear distortions, because ideal linear converters are not available. Practically, any converter can be considered as a linear one, when an output signal is very small. However, the influence of noise increases significantly and signal-to-noise ratio decreases at lower signals. When the output signal is increasing, the nonlinear distortions are also augmenting. If the wide spectrum vibration is measured, conventional methods face a harmonic distortion as well as intermodulation effects. Purpose of this research is to develop a measurement method of wide spectrum vibration by using a converter described by a nonlinear function of type f(x), where x =x(t) denotes the dependence of coordinate x on time t due to the vibration. Parameter x(t) describing the vibration is expressed as Fourier series. The spectral components of the converter output f(x(t)) are determined by using Fourier transform. The obtained system of nonlinear equations is solved using the least squares technique that permits to find x(t) in the presence of noise. This method allows one to carry out the absolute or relative vibration measurements. High resistance to noise is typical for the absolute vibration measurement, but it is necessary to know the Taylor expansion coefficients of the function f(x). If the Taylor expansion is not known, the relative measurement of vibration parameters is also possible, but with lower resistance to noise. This method allows one to eliminate the influence of nonlinear distortions to the measurement results, and consequently to eliminate harmonic distortion and intermodulation effects. The use of nonlinear properties of the converter for measurement gives some advantages related to an increased frequency range of the output signal (consequently increasing the number of equations) that allows one to decrease the noise influence on

  20. Vibration-type particle separation device with piezoceramic vibrator (United States)

    Ooe, Katsutoshi; Doi, Akihiro


    During hemanalysis, it is necessary to separate blood cells from whole blood. Many blood separation methods, for example, centrifugation and filtering, are in practical use. However, the use of these methods involves problems from the perspectives of processing speed and processing volume. We develop new types of blood separation devices that use piezo-ceramic vibrators. The first device uses a capillary. One end of the capillary is fixed to the device frame, and the other is fixed to a piezo-ceramic vibrator. The vibrator transmits bending waves to the capillary. This device can process only a small amount of solution; therefore, it is not suitable for hemanalysis. In order to solve this problem, we developed a second device; this device has a pair of thin glass plates with a small gap as a substitute for the capillary used in the first device. These devices are based on the fact that particles heavier than water move toward transverse velocity antinodes while those lighter than water move toward velocity nodes. In this report, we demonstrate the highspeed separation of silica microbeads and 50-vol% glycerol water by using these devices. The first device can separate the abovementioned solution within 3 min while the second can separate it within 1 min. Both devices are driven by a rectangular wave of 15 to 20 Vpp. Furthermore, it has been confirmed that red blood cells are separated from diluted whole blood using the first device within approximately 1 min. These devices have transparency, so they can compose as the analysis system with the chemical analyzer easily.

  1. Prevalence and characteristics of vibrator use by women in the United States: results from a nationally representative study. (United States)

    Herbenick, Debra; Reece, Michael; Sanders, Stephanie; Dodge, Brian; Ghassemi, Annahita; Fortenberry, J Dennis


    Although vibrators are commonly recommended by clinicians as adjunct to treatment for female sexual dysfunction, and for sexual enhancement, little is known about their prevalence or correlates of use. The aim of this study was to determine the lifetime and recent prevalence of women's vibrator use during masturbation and partnered sex, and the correlates of use related to sociodemographic variables, health behaviors, and sexual function. A nationally representative sample of 3,800 women aged 18-60 years were invited to participate in a cross-sectional Internet-based survey; 2,056 (54.1%) participated. The prevalence of vibrator use, the relationship between vibrator use and physical and psychological well-being (as assessed by the Centers for Disease Control and Prevention [CDC] Healthy Days measure) and health-promoting behaviors, the relationship between vibrator use and women's scores on the Female Sexual Function Index, and an assessment of the frequency and severity of side effects potentially associated with vibrator use. The prevalence of women's vibrator use was found to be 52.5% (95% CI 50.3-54.7%). Vibrator users were significantly more likely to have had a gynecologic exam during the past year (P health-promoting behaviors and positive sexual function, and rarely associated with side effects. Clinicians may find these data useful in responding to patients' sexual issues and recommending vibrator use to improve sexual function. Further research on the relationships between vibrator use and sexual health is warranted.

  2. Identification of Bearing Failure Using Signal Vibrations (United States)

    Yani, Irsyadi; Resti, Yulia; Burlian, Firmansyah


    Vibration analysis can be used to identify damage to mechanical systems such as journal bearings. Identification of failure can be done by observing the resulting vibration spectrum by measuring the vibration signal occurring in a mechanical system Bearing is one of the engine elements commonly used in mechanical systems. The main purpose of this research is to monitor the bearing condition and to identify bearing failure on a mechanical system by observing the resulting vibration. Data collection techniques based on recordings of sound caused by the vibration of the mechanical system were used in this study, then created a database system based bearing failure due to vibration signal recording sounds on a mechanical system The next step is to group the bearing damage by type based on the databases obtained. The results show the percentage of success in identifying bearing damage is 98 %.

  3. Cleaning device for vibrational hose filter

    Energy Technology Data Exchange (ETDEWEB)

    Engels, R


    Filter hoses out of web in dust separators can be cleaned by enforced vibrations. The efficiency of the cleaning is a maximum if the vibrations are at about the individual frequency of the whole arrangement. In the interior of the hose a cage from bars parallel to the wall of the hose is placed on its total length. The bars are fixed at one end and connected with a vibration exciter at the other end. The unilaterally fixed vibration bars can be adjusted to the individual frequency of the vibration exciter. If the hose filter is flown through from the outer to the inner side the vibration bars serve as a supporting body. In the reverse case the bars are placed on the outer side of the hose filter.

  4. Research In Diagnosing Bearing Defects From Vibrations (United States)

    Zoladz, T.; Earhart, E.; Fiorucci, T.


    Report describes research in bearing-defect signature analysis - use of vibration-signal analysis to diagnose defects in roller and ball bearings. Experiments performed on bearings in good condition and other bearings in which various parts scratched to provide known defects correlated with vibration signals. Experiments performed on highly instrumented motor-driven rotor assembly at speeds up to 10,050 r/min, using accelerometers, velocity probes, and proximity sensors mounted at various locations on assembly to measure vibrations.

  5. Characteristic molecular vibrations of adenosine receptor ligands. (United States)

    Chee, Hyun Keun; Yang, Jin-San; Joung, Je-Gun; Zhang, Byoung-Tak; Oh, S June


    Although the regulation of membrane receptor activation is known to be crucial for molecular signal transduction, the molecular mechanism underlying receptor activation is not fully elucidated. Here we study the physicochemical nature of membrane receptor behavior by investigating the characteristic molecular vibrations of receptor ligands using computational chemistry and informatics methods. By using information gain, t-tests, and support vector machines, we have identified highly informative features of adenosine receptor (AdoR) ligand and corresponding functional amino acid residues such as Asn (6.55) of AdoR that has informative significance and is indispensable for ligand recognition of AdoRs. These findings may provide new perspectives and insights into the fundamental mechanism of class A G protein-coupled receptor activation. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  6. Design fix for vibration-induced wear in fuel pin bundles

    International Nuclear Information System (INIS)

    Naas, D.F.; Heck, E.N.


    In summary, results at 45,000 MWd/MTM burnup from the FFTF mixed oxide fuel pin irradiation tests in EBR-II show that reduction of the initial fuel pin bundle clearance and use of 20 percent cold-worked stainless steel ducts virtually eliminate vibration and wear observed in an initial series of 61-pin tests

  7. Numerical investigation on vibration characteristics of a micro-speaker diaphragm considering thermoforming effects

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeong Min; Park, Ke Un [Seoul National University of Science and Technology, Seoul (Korea, Republic of)


    Micro-speaker diaphragms play an important role in generating desired sound responses, and are designed to have thin membrane shapes for flexibility in the axial direction. The micro-speaker diaphragms are formed from thin polymer film through the thermoforming process, in which local thickness reductions occur due to strain localization. This thickness reduction results in a change in vibration characteristics of the diaphragm and different sound responses from that of the original design. In this study, the effect of this thickness change in the diaphragm on its vibration characteristics is numerically investigated by coupling thermoforming simulation, structural analysis and modal analysis. Thus, the thickness change in the diaphragm is calculated from the thermoforming simulation, and reflected in the further structural and modal analyses in order to estimate the relevant stiffness and vibration modes. Comparing these simulation results with those from a diaphragm with the uniform thickness, it is found that a local thickness reduction results in the stiffness reduction and the relevant change in the natural frequencies and the corresponding vibration modes.

  8. Numerical investigation on vibration characteristics of a micro-speaker diaphragm considering thermoforming effects

    International Nuclear Information System (INIS)

    Kim, Kyeong Min; Park, Ke Un


    Micro-speaker diaphragms play an important role in generating desired sound responses, and are designed to have thin membrane shapes for flexibility in the axial direction. The micro-speaker diaphragms are formed from thin polymer film through the thermoforming process, in which local thickness reductions occur due to strain localization. This thickness reduction results in a change in vibration characteristics of the diaphragm and different sound responses from that of the original design. In this study, the effect of this thickness change in the diaphragm on its vibration characteristics is numerically investigated by coupling thermoforming simulation, structural analysis and modal analysis. Thus, the thickness change in the diaphragm is calculated from the thermoforming simulation, and reflected in the further structural and modal analyses in order to estimate the relevant stiffness and vibration modes. Comparing these simulation results with those from a diaphragm with the uniform thickness, it is found that a local thickness reduction results in the stiffness reduction and the relevant change in the natural frequencies and the corresponding vibration modes.

  9. 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.


    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

  10. The Mechanism of Ultrasonic Vibration on Grain Refining and Degassing in GTA Spot Welding of Copper Joints. (United States)

    Al-Ezzi, Salih; Quan, Gaofeng; Elrayah, Adil


    This paper examines the effect of ultrasonic vibration (USV) on grain size and interrupted porosity in Gas Tungsten Arc (GTA) spot-welded copper. Grain size was refined by perpendicularly attaching a transducer to the welded sheet and applying USV to the weld pool for a short time (0, 2, 4, and 6 s) in addition improvements to the degassing process. Results illustrate a significant reduction of grain size (57%). Notably, USV provided interaction between reformations (fragmentation) and provided nucleation points (detaching particles from the fusion line) for grains in the nugget zone and the elimination of porosity in the nugget zone. The GTA spot welding process, in conjunction with USV, demonstrated an improvement in the corrosion potential for a copper spot-welded joint in comparison to the joint welded without assistance of USV. Finally, welding of copper by GTA spot welding in conjunction with ultrasound for 2 s presented significant mechanical properties.

  11. First international conference on vibration control in optics and metrology

    International Nuclear Information System (INIS)

    Baker, L.R.


    This book contains 27 selections. Some of the titles are: Use of optics for vibration analysis of automotive components; Use of pulsed lasers for vibration analysis in the nuclear power industry; Vibration analysis of photocopiers; Control of ground vibrations; Design of low-vibration buildings: two case histories; and Continuous pulsed electronic speckle pattern interferometry

  12. Developed vibration waveform monitoring unit for CBM

    International Nuclear Information System (INIS)

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


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

  13. Electromagnetic Vibration Energy Harvesting for Railway Applications

    Directory of Open Access Journals (Sweden)

    Bradai S.


    Full Text Available Safe localization of trains via GPS and wireless sensors is essential for railway traffic supervision. Especially for freight trains and because normally no power source is available on the wagons, special solutions for energy supply have to be developed based on energy harvesting techniques. Since vibration is available in this case, it provides an interesting source of energy. Nevertheless, in order to have an efficient design of the harvesting system, the existing vibration needs to be investigated. In this paper, we focus on the characterization of vibration parameters in railway application. We propose an electromagnetic vibration converter especially developed to this application. Vibration profiles from a train traveling between two German cities were measured using a data acquisition system installed on the train’s wagon. Results show that the measured profiles present multiple frequency signals in the range of 10 to 50 Hz and an acceleration of up to 2 g. A prototype for a vibration converter is designed taking into account the real vibration parameters, robustness and integrability requirements. It is based on a moving coil attached to a mechanical spring. For the experimental emulation of the train vibrations, a shaker is used as an external artificial vibration source controlled by a laser sensor in feedback. A maximum voltage of 1.7 V peak to peak which corresponds to a maximum of 10 mW output power where the applied excitation frequency is close to the resonant frequency of the converter which corresponds to 27 Hz.

  14. The Efficacy of Anti-vibration Gloves (United States)

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


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

  15. Axisymmetric vibrations of thick shells of revolution

    International Nuclear Information System (INIS)

    Suzuki, Katsuyoshi; Kosawada, Tadashi; Takahashi, Shin


    Axisymmetric shells of revolution are used for chemical plants, nuclear power plants, aircrafts, structures and so on, and the elucidation of their free vibration is important for the design. In this study, the axisymmetric vibration of a barrel-shaped shell was analyzed by the modified thick shell theory. The Lagrangian during one period of the vibration of a shell of revolution was determined, and from its stopping condition, the vibration equations and the boundary conditions were derived. The vibration equations were analyzed strictly by using the series solution. Moreover, the basic equations for the strain of a shell and others were based on those of Love. As the examples of numerical calculation, the natural frequency and vibration mode of the symmetrical shells of revolution fixed at both ends and supported at both ends were determined, and their characteristics were clarified. By comparing the results of this study with the results by thin shell theory, the effects of shearing deformation and rotary inertia on the natural frequency and vibration mode were clarified. The theoretical analysis and the numerical calculation are described. The effects of shearing deformation and rotary inertia on the natural frequency became larger in the higher order vibration. The vibration mode did not much change in both theories. (Kako, I.)

  16. Aircraft gas turbine engine vibration diagnostics

    Directory of Open Access Journals (Sweden)

    Stanislav Fábry


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

  17. Ergonomic Evaluation of Vibrations of a Rototiller with New Blade

    Directory of Open Access Journals (Sweden)

    H Gholami


    represents a significant contribution of the combustion engine in vibration of the examined rototiller. Meanwhile, contribution of the engine in the total measured vibration was more than 50% at different rotational speeds and different directions. The minimum engine contribution was measured equal to 56.39% in z-direction at 155 rpm, whereas the maximum engine contribution was observed equal to 79.5%, in x-direction and rotational speed of 215 rpm. These results indicate the importance of selecting a proper combustion engine for reducing the rototiller vibration. It should be noted that the contribution of the engine in total vibration reached its minimum value at the speed related to the maximum generated torque, i.e., 185 rpm of the rotor speed. This result indicates that using the combustion engine in its optimum speed reduces the entire device vibration in the vertical direction. By increasing the rotational speed of the blades in the y-direction, engine contribution in device vibration showed different trends in compare to the other directions. The most value was equal to 74.25% which was obtained at the rotation speed of 185 rpm. By increasing blade rotational speed from 155 rpm to 215 rpm, the engine contribution in device vibration in the z direction and the total acceleration steadily increased. Conclusions With growing mechanization and entering various types of machines to the farm, importance of considerations to human health is also increased, especially in working with rotational machines. Therefore, the current study was undertaken with the specific attention to the rototillers operational vibration at the handle/hand interface. Results of the conducted experiments showed that vibration of the examined rototiller depends more on the operation of the mounted combustion engine, rather than the soil working blades. Therefore, it is suggested to select a higher quality engine with less vibration or isolate the engine from chassis by a damper (such as a compressed

  18. Flow induced vibrations of piping

    International Nuclear Information System (INIS)

    Gibert, R.J.; Axisa, F.


    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. Radon reduction

    International Nuclear Information System (INIS)

    Hamilton, M.A.


    During a radon gas screening program, elevated levels of radon gas were detected in homes on Mackinac Island, Mich. Six homes on foundations with crawl spaces were selected for a research project aimed at reducing radon gas concentrations, which ranged from 12.9 to 82.3 pCi/l. Using isolation and ventilation techniques, and variations thereof, radon concentrations were reduced to less than 1 pCi/l. This paper reports that these reductions were achieved using 3.5 mil cross laminated or 10 mil high density polyethylene plastic as a barrier without sealing to the foundation or support piers, solid and/or perforated plastic pipe and mechanical fans. Wind turbines were found to be ineffective at reducing concentrations to acceptable levels. Homeowners themselves installed all materials


    Directory of Open Access Journals (Sweden)

    Miloš Milovančević


    Full Text Available The purpose of the research presented in this paper is the development of the optimal micro configuration for vibration monitoring of pumping aggregate, based on Microchip’s microcontroller (MC. Hardware used is 10-bit MC, upgraded with 12/bit A/D converter. Software for acquisition and data analysis is optimized for testing turbo pumps with rotation speed up to 2000 rpm. This software limitation is set for automatic diagnostics and for individual and manual vibro-diagnostic; the only limitation is set by accelerometer performance. The authors have performed numerous measurements on a wide range of turbo aggregates for establishing the operational condition of pumping aggregates.

  1. Introduction to vibrations and waves

    CERN Document Server

    Pain, H John


    Based on the successful multi-edition book "The Physics ofVibrations and Waves" by John Pain, the authors carry overthe simplicity and logic of the approach taken in the originalfirst edition with its focus on the patterns underlying andconnecting so many aspects of physical behavior, whilst bringingthe subject up-to-date so it is relevant to teaching in the21st century.The transmission of energy by wave propagation is a key conceptthat has applications in almost every branch of physics withtransmitting mediums essentially acting as a continuum of coupledoscillators. The characterization of t

  2. Vibration diagnostics instrumentation for ILC

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, A.


    The future e{sup -}e{sup +} 500 GeV International Linear Collider will rely on unprecedented nanometer scale particle beam size at the interaction point, in order to achieve the design luminosity. Tight tolerances on static and dynamic alignment of the accelerator cavities and optical components are demanded to transport and focus the high energy electron and positron beams with reasonable position jitter and low emittance. A brief review of techniques and devices evaluated and developed so far for the vibration diagnostics of the machine is presented in this paper. (orig.)

  3. Vibrational Spectroscopy of Chromatographic Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jeanne E. Pemberton


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

  4. Wideband Piezomagnetoelastic Vibration Energy Harvesting

    DEFF Research Database (Denmark)

    Lei, Anders; Thomsen, Erik Vilain


    This work presents a small-scale wideband piezomagnetoelastic vibration energy harvester (VEH) aimed for operation at frequencies of a few hundred Hz. The VEH consists of a tape-casted PZT cantilever with thin sheets of iron foil attached on each side of the free tip. The wideband operation...... is achieved by placing the cantilever in a magnetic field induced by either one or two magnets located oppositely of the cantilever. The attraction force created by the magnetic field and iron foils introduces a mechanical force in opposite direction of the cantilevers restoring force causing a spring...

  5. Vibration diagnostics instrumentation for ILC

    International Nuclear Information System (INIS)

    Bertolini, A.


    The future e - e + 500 GeV International Linear Collider will rely on unprecedented nanometer scale particle beam size at the interaction point, in order to achieve the design luminosity. Tight tolerances on static and dynamic alignment of the accelerator cavities and optical components are demanded to transport and focus the high energy electron and positron beams with reasonable position jitter and low emittance. A brief review of techniques and devices evaluated and developed so far for the vibration diagnostics of the machine is presented in this paper. (orig.)

  6. Multivariate Analysis of Ladle Vibration (United States)

    Yenus, Jaefer; Brooks, Geoffrey; Dunn, Michelle


    The homogeneity of composition and uniformity of temperature of the steel melt before it is transferred to the tundish are crucial in making high-quality steel product. The homogenization process is performed by stirring the melt using inert gas in ladles. Continuous monitoring of this process is important to make sure the action of stirring is constant throughout the ladle. Currently, the stirring process is monitored by process operators who largely rely on visual and acoustic phenomena from the ladle. However, due to lack of measurable signals, the accuracy and suitability of this manual monitoring are problematic. The actual flow of argon gas to the ladle may not be same as the flow gage reading due to leakage along the gas line components. As a result, the actual degree of stirring may not be correctly known. Various researchers have used one-dimensional vibration, and sound and image signals measured from the ladle to predict the degree of stirring inside. They developed online sensors which are indeed to monitor the online stirring phenomena. In this investigation, triaxial vibration signals have been measured from a cold water model which is a model of an industrial ladle. Three flow rate ranges and varying bath heights were used to collect vibration signals. The Fast Fourier Transform was applied to the dataset before it has been analyzed using principal component analysis (PCA) and partial least squares (PLS). PCA was used to unveil the structure in the experimental data. PLS was mainly applied to predict the stirring from the vibration response. It was found that for each flow rate range considered in this study, the informative signals reside in different frequency ranges. The first latent variables in these frequency ranges explain more than 95 pct of the variation in the stirring process for the entire single layer and the double layer data collected from the cold model. PLS analysis in these identified frequency ranges demonstrated that the latent

  7. CRBRP flow induced vibration program

    Energy Technology Data Exchange (ETDEWEB)

    Novendstern, E H [Westinghouse Advanced Reactor Division, Madison, PA (United States); Grochowski, F A; Yang, T M [General Electric Co., Fast Breeder Reactor Department, Sunnyvale, CA (United States); Ryan, J A; Mulcahy, T M


    The program to assure the structural adequacy of Clinch River Breeder Reactor (CRBRP) components during its planned 30 years of operation is described. The program includes (1) an assessment of reactor components relative to their susceptibility to FIV, (2) designing to minimize component excitation due to Fluid induced vibrations (FIV), (3) scale model tests to measure structural response during simulated operating conditions and (4) preoperational tests. An overview of the CRBRP test program is described. Additionally, details of scale model testing of reactor internals and the steam generator is described in more detail. (author)

  8. Adaptive photodetectors for vibration monitoring

    International Nuclear Information System (INIS)

    Sokolov, I.A.


    We present characteristics of laser vibrometer using semiconductor GaAs and molecular SnS 2 adaptive photodetectors (AP) based on the effect of the non-steady-state photoelectromotive force. AP enable efficient direct conversion of high-frequency phase modulation of speckle-like optical wave reflected from the vibrating object into an output electrical signal with concomitant setting of optimal operation point of the interferometer and suppression of amplitude laser noise. The sensitivity of the setup is analyzed and further improvements in operation of AP are discussed

  9. Semiclassical theory of plate vibrations

    International Nuclear Information System (INIS)

    Bogomolny, E.; Hugues, E.


    The bi-harmonic equation of flexural vibrations of elastic plates is studied by a semiclassical method which can easily be generalized for other models of wave propagation. The surface and perimeter terms of the asymptotic number of levels are derived exactly. The next constant term is also derived. A semiclassical approximation of the quantization condition is obtained. A Berry-Tabor formula and a Gutzwiller trace formula are deduced for the integrable and chaotic cases respectively. From 600 eigenvalues of a clamped stadium plate obtained by a specially developed numerical algorithm, the trace formula is assessed, looking at its Fourier transform compared with the membrane case. (author)

  10. Wear reduction through piezoelectrically-assisted ultrasonic lubrication

    International Nuclear Information System (INIS)

    Dong, Sheng; J Dapino, Marcelo


    Traditional lubricants are undesirable in harsh aerospace environments and certain automotive applications. Ultrasonic vibrations can be used to reduce and modulate the effective friction coefficient between two sliding surfaces. This paper investigates the relationship between friction force reduction and wear reduction in ultrasonically lubricated surfaces. A pin-on-disc tribometer is modified through the addition of a piezoelectric transducer which vibrates the pin at 22 kHz in the direction perpendicular to the rotating disc surface. Friction and wear metrics including volume loss, surface roughness, friction forces and apparent stick-slip effects are measured without and with ultrasonic vibrations at three different sliding velocities. SEM imaging and 3D profilometry are used to characterize the wear surfaces and guide model development. Over the range of speeds considered, ultrasonic vibrations reduce the effective friction force up to 62% along with a wear reduction of up to 49%. A simple cube model previously developed to quantify friction force reduction is implemented which describes wear reduction within 15% of the experimental data. (paper)

  11. First-principles analysis of the Raman spectrum of vitreous silica: comparison with the vibrational density of states

    International Nuclear Information System (INIS)

    Umari, P; Pasquarello, Alfredo


    The HH and HV Raman spectra of vitreous silica are calculated from first principles for a model structure consisting of a disordered network of corner-sharing tetrahedra, for which the vibrational properties were obtained previously. We analyse the contribution of specific atomic motions to the Raman spectra and perform a detailed comparison with respect to the vibrational density of states. We find that the HV spectrum closely resembles the vibrational density of states. By comparison, the HH spectrum shows significant differences and arises almost exclusively from oxygen vibrations

  12. First-principles analysis of the Raman spectrum of vitreous silica: comparison with the vibrational density of states

    Energy Technology Data Exchange (ETDEWEB)

    Umari, P; Pasquarello, Alfredo [Institut de Theorie des Phenomenes Physiques (ITP), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Institut Romand de Recherche Numerique en Physique des Materiaux (IRRMA), CH-1015 Lausanne (Switzerland)


    The HH and HV Raman spectra of vitreous silica are calculated from first principles for a model structure consisting of a disordered network of corner-sharing tetrahedra, for which the vibrational properties were obtained previously. We analyse the contribution of specific atomic motions to the Raman spectra and perform a detailed comparison with respect to the vibrational density of states. We find that the HV spectrum closely resembles the vibrational density of states. By comparison, the HH spectrum shows significant differences and arises almost exclusively from oxygen vibrations.

  13. Sound & Vibration 20 Design Guidelines for Health Care Facilities

    CERN Document Server

    Tocci, Gregory; Cavanaugh, William


    Sound, vibration, noise and privacy have significant impacts on health and performance. As a result, they are recognized as essential components of effective health care environments. However, acoustics has only recently become a prominent consideration in the design, construction, and operation of healthcare facilities owing to the absence, prior to 2010, of clear and objective guidance based on research and best practices. Sound & Vibration 2.0 is the first publication to comprehensively address this need. Sound & Vibration 2.0 is the sole reference standard for acoustics in health care facilities and is recognized by: the 2010 FGI Guidelines for the Design and Construction of Health Care Facilities (used in 60 countries); the US Green Building Council’s LEED for Health Care (used in 87 countries); The Green Guide for Health Care V2.2; and the International Code Council (2011). Sound & Vibration 2.0 was commissioned by the Facility Guidelines Institute in 2005, written by the Health Care Acous...

  14. Real-time vibration compensation for large telescopes (United States)

    Böhm, M.; Pott, J.-U.; Sawodny, O.; Herbst, T.; Kürster, M.


    We compare different strategies for minimizing the effects of telescope vibrations to the differential piston (optical pathway difference) for the Near-InfraRed/Visible Adaptive Camera and INterferometer for Astronomy (LINC-NIRVANA) at the Large Binocular Telescope (LBT) using an accelerometer feedforward compensation approach. We summarize, why this technology is important for LINC-NIRVANA, and also for future telescopes and already existing instruments. The main objective is outlining a solution for the estimation problem in general and its specifics at the LBT. Emphasis is put on realistic evaluation of the used algorithms in the laboratory, such that predictions for the expected performance at the LBT can be made. Model-based estimation and broad-band filtering techniques can be used to solve the estimation task, and the differences are discussed. Simulation results and measurements are shown to motivate our choice of the estimation algorithm for LINC-NIRVANA. The laboratory setup is aimed at imitating the vibration behaviour at the LBT in general, and the M2 as main contributor in particular. For our measurements, we introduce a disturbance time series which has a frequency spectrum comparable to what can be measured at the LBT on a typical night. The controllers' ability to suppress vibrations in the critical frequency range of 8-60 Hz is demonstrated. The experimental results are promising, indicating the ability to suppress differential piston induced by telescope vibrations by a factor of about 5 (rms), which is significantly better than any currently commissioned system.

  15. Autonomous target recognition using remotely sensed surface vibration measurements (United States)

    Geurts, James; Ruck, Dennis W.; Rogers, Steven K.; Oxley, Mark E.; Barr, Dallas N.


    The remotely measured surface vibration signatures of tactical military ground vehicles are investigated for use in target classification and identification friend or foe (IFF) systems. The use of remote surface vibration sensing by a laser radar reduces the effects of partial occlusion, concealment, and camouflage experienced by automatic target recognition systems using traditional imagery in a tactical battlefield environment. Linear Predictive Coding (LPC) efficiently represents the vibration signatures and nearest neighbor classifiers exploit the LPC feature set using a variety of distortion metrics. Nearest neighbor classifiers achieve an 88 percent classification rate in an eight class problem, representing a classification performance increase of thirty percent from previous efforts. A novel confidence figure of merit is implemented to attain a 100 percent classification rate with less than 60 percent rejection. The high classification rates are achieved on a target set which would pose significant problems to traditional image-based recognition systems. The targets are presented to the sensor in a variety of aspects and engine speeds at a range of 1 kilometer. The classification rates achieved demonstrate the benefits of using remote vibration measurement in a ground IFF system. The signature modeling and classification system can also be used to identify rotary and fixed-wing targets.

  16. Acute effect of whole body vibration on postural control in congenitally blind subjects: a preliminary evidence. (United States)

    di Cagno, Alessandra; Giombini, Arrigo; Iuliano, Enzo; Moffa, Stefano; Caliandro, Tiziana; Parisi, Attilio; Borrione, Paolo; Calcagno, Giuseppe; Fiorilli, Giovanni


    The purpose of this study was to investigate the acute effects of whole body vibration at optimal frequency, on postural control in blind subjects. Twenty-four participants, 12 congenital blind males (Experimental Group), and 12 non-disabled males with no visual impairment (Control Groups) were recruited. The area of the ellipse and the total distance of the center of pressure displacements, as postural control parameters, were evaluated at baseline (T0), immediately after the vibration (T1), after 10 min (T10) and after 20 min (T20). Whole body vibration protocol consisted into 5 sets of 1 min for each vibration, with 1 min rest between each set on a vibrating platform. The total distance of center of pressure showed a significant difference (p < 0.05) amongst groups, while the area remained constant. No significant differences were detected among times of assessments, or in the interaction group × time. No impairments in static balance were found after an acute bout of whole body vibration at optimal frequency in blind subjects and, consequently, whole body vibration may be considered as a safe application in individuals who are blind.

  17. Study on the Effect of Reciprocating Pump Pipeline System Vibration on Oil Transportation Stations

    Directory of Open Access Journals (Sweden)

    Hongfang Lu


    Full Text Available Due to the periodic movement of the piston in the reciprocating pump, the fluid will cause a pressure pulsation, and the resulting pipeline vibration may lead to instrument distortion, pipe failure and equipment damage. Therefore, it is necessary to study the vibration phenomena of reciprocating pump pipelines based on pressure pulsation theory. This paper starts from the reciprocating pump pipe pressure pulsation caused by a fluid, pressure pulsation in the pipeline and the unbalanced exciting force is calculated under the action of the reciprocating pump. Then, the numerical simulation model is established based on the pipe beam model, and the rationality of the numerical simulation method is verified by indoor experiments. Finally, a case study is taken as an example to analyze the vibration law of the pipeline system, and vibration reduction measures are proposed. The following main conclusions are drawn from the analysis: (1 unbalanced exciting forces are produced in the elbows or tee joints, and it can also influence the straight pipe to different levels; (2 in actual engineering, it should be possible to prevent the simultaneous settlement of multiple places; (3 the vibration amplitude increases with the pipe thermal stress, and when the oil temperature is higher than 85 °C, it had a greater influence on the vertical vibration amplitude of the pipe.

  18. Design and fabrication of an energy-harvesting device using vibration absorber (United States)

    Heidari, Hamidreza; Afifi, Arash


    Energy-harvesting devices collect energy that is being wasted and convert to the electrical energy. For this reason, this type of devices is considered as a convenient alternative to traditional batteries. In this paper, experimental examinations were performed to investigate the application of harvesting device for the reduction of the vibration amplitude in a vibration system and also increase the efficiency of energy-harvesting device. This study focuses on the energy-harvesting device as both producing electrical device and a vibration disabled absorber. In this regard, a motion-based energy-harvesting device is designed to produce electrical energy and also eliminate vibrations of a two joint-end beam which is located under the harmonic excitation force. Then, the governing equations of the forced motion on the main beam are derived and energy-harvesting system are simulated. In addition, the system designed by MATLAB simulation is explained and its results are expressed. Finally, a prototype of the system was made and the ability of the energy-harvesting device to absorb the original system vibrations, as well as parameters impact on the efficiency of energy harvesting is investigated. Experimental results show that the energy-harvesting device, in addition to producing electric current with a maximum value of 1.5V, reduces 94% of the original system vibrations.

  19. Investigation and analysis the vibration of handles of chainsaw without cutting

    Directory of Open Access Journals (Sweden)

    M Feyzi


    (VMI-192. The accelerometer mounted on an adapter inserted between the handle and accelerometer. The experiments were conducted in split plot completely randomized design. Ninety tests in two handles, three speeds of engine, three perpendicular axes and five repeats were conducted. The vibration acceleration at various conditions was measured and the root mean square of vibration acceleration was calculated based on acceleration-time spectrum. To investigate the characteristics of vibration in different speeds, the vibration spectrums in time domain were converted to spectrums in frequency domain. The frequency weighted RMS acceleration at 1/3rd octave bands from 6.3Hz to 1250Hz and the vibration total value was calculated from frequency spectrum. To analyze the obtained data, SAS software was used. Furthermore, the Duncan's multiple range tests were used to compare the RMS values. Results and Discussion: Main source of vibration of chainsaw was single cylinder engine. The acceleration spectra of employed chainsaw had peaks in frequencies in accordance with the speed of engine. These peaks in 2800 rpm, 10000 rpm and 13300 rpm speeds of engine occurred in 46.5Hz, 166.5Hz and 221.5Hz, respectively. To achieve a safe design for handle of portable tools, identifying the frequency which leads to the maximum value of vibration acceleration is very useful. To avoid the resonance phenomenon, the natural frequency of handle must be far from dominant frequency of engine. The results of ANOVA showed that the RMS acceleration in different axes and different speeds were significant at 1% level. The maximum value of vibration acceleration, at idling engine speed, occurred in the lateral axis. In addition, the mentioned variable was maximized in normal and axial axes at nominal and racing speeds, respectively. The total value of vibration was increased when the speed of engine moving away from nominal speed. This increase in rear handle is very larger than front handle. The total

  20. Free vibration characteristics analysis of rectangular plate with rectangular opening based on Fourier series method

    Directory of Open Access Journals (Sweden)

    WANG Minhao


    Full Text Available Plate structures with openings are common in many engineering structures. The study of the vibration characteristics of such structures is directly related to the vibration reduction, noise reduction and stability analysis of an overall structure. This paper conducts research into the free vibration characteristics of a thin elastic plate with a rectangular opening parallel to the plate in an arbitrary position. We use the improved Fourier series to represent the displacement tolerance function of the rectangular plate with an opening. We can divide the plate into an eight zone plate to simplify the calculation. We then use linear springs, which are uniformly distributed along the boundary, to simulate the classical boundary conditions and the boundary conditions of the boundaries between the regions. According to the energy functional and variational method, we can obtain the overall energy functional. We can also obtain the generalized eigenvalue matrix equation by studying the extremum of the unknown improved Fourier series expansion coefficients. We can then obtain the natural frequencies and corresponding vibration modes of the rectangular plate with an opening by solving the equation. We then compare the calculated results with the finite element method to verify the accuracy and effectiveness of the method proposed in this paper. Finally, we research the influence of the boundary condition, opening size and opening position on the vibration characteristics of a plate with an opening. This provides a theoretical reference for practical engineering application.