WorldWideScience

Sample records for vibration tests performed

  1. Virtual Shaker Testing: Simulation Technology Improves Vibration Test Performance

    Science.gov (United States)

    Ricci, Stefano; Peeters, Bart; Fetter, Rebecca; Boland, Doug; Debille, Jan

    2008-01-01

    In the field of vibration testing, the interaction between the structure being tested and the instrumentation hardware used to perform the test is a critical issue. This is particularly true when testing massive structures (e.g. satellites), because due to physical design and manufacturing limits, the dynamics of the testing facility often couples with the test specimen one in the frequency range of interest. A further issue in this field is the standard use of a closed loop real-time vibration control scheme, which could potentially shift poles and change damping of the aforementioned coupled system. Virtual shaker testing is a novel approach to deal with these issues. It means performing a simulation which closely represents the real vibration test on the specific facility by taking into account all parameters which might impact the dynamic behavior of the specimen. In this paper, such a virtual shaker testing approach is developed. It consists of the following components: (1) Either a physical-based or an equation-based coupled electro-mechanical lumped parameter shaker model is created. The model parameters are obtained from manufacturer's specifications or by carrying out some dedicated experiments; (2) Existing real-time vibration control algorithm are ported to the virtual simulation environment; and (3) A structural model of the test object is created and after defining proper interface conditions structural modes are computed by means of the well-established Craig-Bampton CMS technique. At this stage, a virtual shaker test has been run, by coupling the three described models (shaker, control loop, structure) in a co-simulation routine. Numerical results have eventually been correlated with experimental ones in order to assess the robustness of the proposed methodology.

  2. Design and Performance Testing of a Novel Three-Dimensional Elliptical Vibration Turning Device

    Directory of Open Access Journals (Sweden)

    Jieqiong Lin

    2017-10-01

    Full Text Available A novel three-dimensional (3D elliptical vibration turning device which is on the basis of the leaf-spring-flexure-hinges-based (LSFH-based double parallel four-bar linkages (DPFLMs has been proposed. In order to evaluate the performance of the developed 3D elliptical vibration cutting generator (EVCG, the off-line tests were carried out to investigate the stroke, dynamic performance, resolution, tracking accuracy and hysteresis along the three vibration axes. Experimental results indicate that the maximum stroke of three vibration axes can reach up to 26 μm. The working bandwidth can reach up to 1889 Hz. The resolution and hysteresis tests show that the developed 3D EVCG has a good tracking accuracy, relative high resolution and low hysteresis, which is appropriate for micro/nano machining. Kinematical modeling is carried out to investigate the tool vibration trajectory. Experimental results shown that the simulation results agree well with the experimental one, which indicate that the developed 3D EVCG can be used as an option for micro/nano machining.

  3. Evaluating vibration performance of a subsea pump module by full-scale testing and numerical modelling

    NARCIS (Netherlands)

    Beek, P.J.G. van; Pereboom, H.P.; Slot, H.J.

    2016-01-01

    Prior to subsea installation, a subsea system has to be tested to verify whether it performs in accordance with specifications and component specific performance evaluation criteria. It is important to verify that the assembled components work in accordance with the assumptions and design criteria

  4. 49 CFR 178.819 - Vibration test.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Vibration test. 178.819 Section 178.819... Testing of IBCs § 178.819 Vibration test. (a) General. The vibration test must be conducted for the... vibration test. (b) Test method. (1) A sample IBC, selected at random, must be filled and closed as for...

  5. Performance testing of diesel engines using vibrational-acoustical diagnostic methods

    Energy Technology Data Exchange (ETDEWEB)

    Maack, H.H.; Neumann, G.

    1982-01-01

    Vibroacoustic condition monitoring is based on the measurement, processing and analysis of the solid-borne and airborne vibration signals emanating from a machine. Several assemblies belonging to diesel engines have a characteristic signal structure induced by impact excitation. The author proceeds from a generalised condition monitoring process to discuss the problem of the origin, transmission, measurement and analysis of vibroacoustic signals from diesel engines and presents a procedure based on a combination of frequency analysis in the temporary elimination of signal components.

  6. 14 CFR 33.83 - Vibration test.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration test. 33.83 Section 33.83... STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.83 Vibration test. (a) Each engine must undergo vibration surveys to establish that the vibration characteristics of those components that...

  7. 14 CFR 33.43 - Vibration test.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration test. 33.43 Section 33.43... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.43 Vibration test. (a) Each engine must undergo a vibration survey to establish the torsional and bending vibration characteristics...

  8. Testing and performance of a new friction damper for seismic vibration control

    Science.gov (United States)

    Martínez, Carlos A.; Curadelli, Oscar

    2017-07-01

    In the last two decades, great efforts were carried out to reduce the seismic demand on structures through the concept of energy dissipation instead of increasing the stiffness and strength. Several devices based on different energy dissipation principles have been developed and implemented worldwide, however, most of the dissipation devices are usually installed using diagonal braces, which entail certain drawbacks on apertures for circulation, lighting or ventilation and architectural or functional requirements often preclude this type of installations. In this work, a conceptual development of a novel energy dissipation device, called Multiple Friction Damper (MFD), is proposed and examined. To verify its characteristics and performance, the MFD was implemented on a single storey steel frame experimental model and tested under different conditions of normal force and real time acceleration records. Experimental results demonstrated that the new MFD constitutes an effective and reliable alternative to control the structural response in terms of displacement and acceleration. A mathematical formulation based on the Wen's model reflecting the nonlinear behaviour of the device is also presented.

  9. Sound insulation and vibration tests for lightweight steel framing floors

    OpenAIRE

    Shi, Wanqing; Edfast, Fredrik; Ågren, Anders

    2000-01-01

    An experimental study of sound insulation and vibrations of lightweight steel framing floors due to different floor construction set up were performed. Floors with 3m, 5m and 7.2m span were tested. The impact and airborne sound insulation for 3m span floor were measured based on ISO 140 in lab condition. Vibration tests were carried out on all three different spans. The vibration transmission loss of the structure was determined from the surface vibration measurements. The fundamental natural...

  10. 49 CFR 178.985 - Vibration test.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Vibration test. 178.985 Section 178.985... Testing of Large Packagings § 178.985 Vibration test. (a) General. All rigid Large Packaging and flexible Large Packaging design types must be capable of withstanding the vibration test. (b) Test method. (1) A...

  11. 33 CFR 159.103 - Vibration test.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vibration test. 159.103 Section...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.103 Vibration test. The device... subjected to a sinusoidal vibration for a period of 12 hours, 4 hours in each of the x, y, and z planes, at...

  12. Laser geodynamic satellite thermal/optical/vibrational analyses and testing, volume 2, book 1 technical report. [retroreflector performance

    Science.gov (United States)

    1975-01-01

    The results are presented of a retroreflector performance improvement program. The following areas of the program are discussed: retroreflector dimensional verification, initial optical performance analysis, LAGEOS test retroreflector rework, final optical performance analysis, optical performance tests, evaluations and conclusions, and laser wavelength evaluation and dihedral angle selection. Data tables, diagrams, graphs, and photographs are included.

  13. Damping Estimation Using Free Decays and Ambient Vibration Tests

    DEFF Research Database (Denmark)

    Magalhães, Filipe; Brincker, Rune; Cunha, Álvaro

    2007-01-01

    The accurate identification of modal damping ratios of Civil Engineering structures is a subject of major importance, as the amplitude of structural vibrations in resonance is inversely proportional to these coefficients. Their experimental identification can be performed either from ambient...... vibration or from free vibration tests. In the last case, the structural response after application of an impulse or after the application of harmonic loads can be used. Ambient vibration tests have the strong advantage of being more practical and economical. However, recent applications of both approaches...

  14. Benefits of Spacecraft Level Vibration Testing

    Science.gov (United States)

    Gordon, Scott; Kern, Dennis L.

    2015-01-01

    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.

  15. Imaging performance comparison between CMOS and sCMOS detectors in a vibration test on large areas using digital holographic interferometry

    Science.gov (United States)

    Flores-Morenoa, J. M.; Torre I., Manuel H. De la; Aguayo, Daniel D.; Fernando Mendoza, S.

    2014-05-01

    A comparison of the interferometric imaging performance of two different cameras during a vibration study is presented. One of the cameras has a high speed CMOS sensor and the second one uses a high resolution (scientific) sCMOS sensor. This comparison is based on the interferometric response as a merit parameter of these sensors which is not a conventional procedure. Even when the current standard for image quality is on the signal to noise ratio calculations, an interferometric test to evaluate the fringe pattern visibility is equivalent to the contrast to noise ratio value. An out of plane digital holographic interferometer is used to test each camera once at the time with the same experimental conditions. The object under study is a metallically framed table with a Formica cover with an observable area of 1.1 m2. The sample is deformed by means of a controlled vibration induced by a tip ended linear step motor. Results from each camera are presented as the retrieved optical phase during the vibration. Finally, some conclusions based on the post processed images are presented suggesting a smoother optical phase obtained with the sCMOS camera.

  16. High force vibration testing with wide frequency range

    Science.gov (United States)

    Romero, Edward F.; Jepsen, Richard A.; Gregory, Danny Lynn

    2013-04-02

    A shaker assembly for vibration testing includes first and second shakers, where the first shaker includes a piezo-electric material for generating vibration. A support structure permits a test object to be supported for vibration of the test object by both shakers. An input permits an external vibration controller to control vibration of the shakers.

  17. Ambient Vibration Test on Reinforced Concrete Bridges

    Directory of Open Access Journals (Sweden)

    Idris Nurul Shazwin

    2016-01-01

    Full Text Available An investigation was carried out to determine dynamic characteristic of reinforced concrete (RC bridges by using ambient vibration test (AVT. The ambient vibration sources on bridges may come from traffic, wind, wave motion and seismic events. AVT describes the dynamic characteristics of the bridge and ground by measuring the natural frequencies using highly sensitive seismometer sensor. This test is beneficial due to light weight equipment and smaller number of operator required, cheap and easy to be handled. It is able to give a true picture of the bridge dynamic behavior without any artificial force excitation when vibration data is recorded. A three-span reinforced concrete bridge located in Sri Medan, Batu Pahat, Johor was measured by using microtremor equipment consist of three units of 1 Hz eigenfrequency passive sensors used in this test was performed in normal operating condition without excitation required from any active sources or short period noise perturbations. Ten measurements were conducted on the bridge deck and ten measurements on the ground surface in order to identify the natural frequencies of the bridge. Several peak frequencies were identified from three components of Fourier Amplitude Spectra (FAS in transverse (North-South, longitudinal (East-West and vertical (Up-Down direction as well as squared average Horizontal to Vertical Spectral Ratio (HVSR of ground response, computed by using Geopsy software. From the result, it was expected the bridge have five vibration modes frequencies in the range of 1.0 Hz and 7.0 Hz with the first two modes in the transverse and longitudinal direction having a frequency 1.0 Hz, the third mode is 2.2 Hz in transverse direction, fourth and fifth mode is 5.8 Hz and 7.0 Hz. For ground natural frequencies are in range 1.0 Hz to 1.3 Hz for North-South direction and 1.0 Hz to 1.6 Hz for East-West direction. Finally the results are compared with several empirical formulas for simple

  18. Measurement of Dynamic Viscoelasticity of Full-Size Wood Composite Panels Using a Vibration Testing Method

    Science.gov (United States)

    Cheng Guan; Houjiang Zhang; John F. Hunt; Lujing Zhou; Dan Feng

    2016-01-01

    The dynamic viscoelasticity of full-size wood composite panels (WCPs) under the free-free vibrational state were determined by a vibration testing method. Vibration detection tests were performed on 194 pieces of three types of full-size WCPs (particleboard, medium density fiberboard, and plywood (PW)). The dynamic viscoelasticity from smaller specimens cut from the...

  19. VLTI-UT vibrations effort and performances

    Science.gov (United States)

    Poupar, Sébastien; Haguenauer, Pierre; Alonso, Jaime; Schuhler, Nicolas; Henriquez, Juan-Pablo; Berger, Jean-Philippe; Bourget, Pierre; Brillant, Stephane; Castillo, Roberto; Gitton, Philippe; Gonte, Frederic; Di Lieto, Nicola; Lizon, Jean-Louis; Merand, Antoine; Woillez, Julien

    2014-07-01

    The ESO Very Large Telescope Interferometer (VLTI) using the Unit Telescope (UT) was strongly affected by vibrations since the first observations. Investigation by ESO on that subject had started in 2007, with a considerable effort since mid 2008. An important number of investigations on various sub-systems (On telescope: Guiding, Passive supports, Train Coude, insulation of electronics cabinets; On Instruments: dedicated campaign on each instruments with a special attention on the ones equipped with Close Cycle Cooler) were realized. Vibrations were not only recorded and analyzed using the usual accelerometers but also using on use sub-systems as InfRared Image Sensor (IRIS) and Multiple Applications Curvature Adaptive Optics (MACAO) and using a specific tool developed for vibrations measurements Mirror vibrAtion Metrology systeM for the Unit Telescope (MAMMUT). Those tools and systems have been used in order to improve the knowledge on telescope by finding sources. The sources whenever it was possible were damped. As known for years, instruments are still the principal sources of vibrations, for the majority of the UT. A special test in which 2 UTs instruments were completely shut down was realized to determine the minimum Optical Path Length (OPL) achievable. Vibrations is now a part of the instruments interface document and during the installation of any new instrument (KMOS) or system (AOF) a test campaign is realized. As a result some modifications (damping of CCC) can be asked in case of non-compliance. To ensure good operational conditions, levels of vibrations are regularly recorded to control any environmental change.

  20. Vibration Performance Comparison Study on Current Fiber Optic Connector Technologies

    Science.gov (United States)

    Ott, Melanie N.; Thomes Jr., William J.; LaRocca, Frank V.; Switzer, Robert C.; Chuska, Rick F.; Macmurphy, Shawn L.

    2008-01-01

    Fiber optic cables are increasingly being used in harsh environments where they are subjected to vibration. Understanding the degradation in performance under these conditions is essential for integration of the fibers into the given application. System constraints oftentimes require fiber optic connectors so subsystems can be removed or assembled as needed. In the present work, various types of fiber optic connectors were monitored in-situ during vibration testing to examine the transient change in optical transmission and the steady-state variation following the event. Inspection of the fiber endfaces and connectors was performed at chosen intervals throughout the testing.

  1. Effect of vibration on visual display terminal work performance.

    Science.gov (United States)

    Hsieh, Yao-Hung; Lin, Chiuhsiang Joe; Chen, Hsiao-Ching

    2007-12-01

    Today electronic visual displays have dramatic use in daily life. Reading these visual displays is subject to their vibration. Using a software-simulation of a vibrated environment, the study investigated the effect of vibration on visual performance and fatigue for several numerical display design characteristics including the font size and the number of digits displayed. Both the frequency and magnitude of vibration had significant effects on the reaction time, accuracy, and visual fatigue. 10 graduate students (23-30 years old; M = 25.6), randomly tested in this experiment, were offered about 25 U.S. dollars for their participation. Numbers in vertical presentation were affected more in vertical vibration than those in horizontal presentation. Analysis showed whenever the display is used in vibration environment, an increased font size may be an effective way to compensate the adverse effect of vibration. The software design of displayed materials must be designed to take the motion effect into consideration to increase the quality of the screen display.

  2. Experimental Research on Vibration Fatigue of CFRP and Its Influence Factors Based on Vibration Testing

    OpenAIRE

    Fan, Zhengwei; Jiang, Yu; Zhang, Shufeng; Chen, Xun

    2017-01-01

    A new research method based on vibration testing for the vibration fatigue of FRP was proposed in this paper. Through the testing on a closed-loop controlled vibration fatigue test system, the vibration fatigue phenomenon of typical carbon-fiber-reinforced plastic (CFRP) cantilevered laminate specimens was carefully studied. Moreover, a method based on the frequency response function was proposed to monitor the fatigue damage accumulation of specimens. On the basis of that, the influence fact...

  3. The Shock Vibration Bulletin. Part 3. Isolation and Damping, Vibration Test Criteria, and Vibration Analysis and Test

    Science.gov (United States)

    1987-01-01

    fatigae equivalent test time of 45-mimates. 1. BACKGROUND subjected to both vibration and loose cargo testing as well an the type and amount of...Environmental Test the track laying environment. Nethods, 10 March 1975. 8. FUTURE EFFORTS 11. Soci, Darrell F., Fatigae Life Estimation Techniques, Technical

  4. 46 CFR 162.050-37 - Vibration test.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Vibration test. 162.050-37 Section 162.050-37 Shipping...: SPECIFICATIONS AND APPROVAL ENGINEERING EQUIPMENT Pollution Prevention Equipment § 162.050-37 Vibration test. (a... and each control of a separator must be subjected to continuous sinusoidal vibration in each of the...

  5. Human Factors Assessment of Vibration Effects on Visual Performance During Launch

    Science.gov (United States)

    Holden, Kritina

    2009-01-01

    The Human Factors Assessment of Vibration Effects on Visual Performance During Launch (Visual Performance) investigation will determine visual performance limits during operational vibration and g-loads on the Space Shuttle, specifically through the determination of minimum readable font size during ascent using planned Orion display formats. Research Summary: The aim of the Human Factors Assessment of Vibration Effects on Visual Performance during Launch (Visual Performance) investigation is to provide supplementary data to that collected by the Thrust Oscillation Seat Detailed Technical Objective (DTO) 695 (Crew Seat DTO) which will measure seat acceleration and vibration from one flight deck and two middeck seats during ascent. While the Crew Seat DTO data alone are important in terms of providing a measure of vibration and g-loading, human performance data are required to fully interpret the operational consequences of the vibration values collected during Space Shuttle ascent. During launch, crewmembers will be requested to view placards with varying font sizes and indicate the minimum readable size. In combination with the Crew Seat DTO, the Visual Performance investigation will: Provide flight-validated evidence that will be used to establish vibration limits for visual performance during combined vibration and linear g-loading. o Provide flight data as inputs to ongoing ground-based simulations, which will further validate crew visual performance under vibration loading in a controlled environment. o Provide vibration and performance metrics to help validate procedures for ground tests and analyses of seats, suits, displays and controls, and human-in-the-loop performance.

  6. Online vibration-based crack detection during fatigue testing

    Energy Technology Data Exchange (ETDEWEB)

    Peeters, B.; Vecchio, A.; Auweraer, H. van der [LMS International, Heverlee (Belgium); Mevel, L. [INRIA, Rennes (France); Vanlanduit, S.; Guillaume, P. [Dept. of Mechanical Engineering, VUB, Brussels (Belgium); Goursat, M. [Rocquencourt, INRIA, Le Chesnay (France)

    2003-07-01

    When performing fatigue tests, it is essential to monitor the degradation of the structure with an increasing number of fatigue cycles. In this article, a vibration-based damage detection method will be proposed. Such a method has the advantage that it operates online with the fatigue test. Especially for structures with very high fatigue strength, it is important that the test does not have to be interrupted. The damage detection method that will be used is based on a residual generated from a stochastic subspace identification method. The basic idea is that a model for the undamaged structure is identified and that, afterwards, vibration measurements from a possibly damaged structure are confronted with this model. A statistical local approach hypothesis testing is used to assess the deviation of the new data from the nominal model. After introducing the damage detection method, its performance will be illustrated on data from a fatigue experiment. The method will be compared to other linear and non-linear vibration-based damage detection methods. (orig.)

  7. Methods of performing downhole operations using orbital vibrator energy sources

    Science.gov (United States)

    Cole, Jack H.; Weinberg, David M.; Wilson, Dennis R.

    2004-02-17

    Methods of performing down hole operations in a wellbore. A vibrational source is positioned within a tubular member such that an annulus is formed between the vibrational source and an interior surface of the tubular member. A fluid medium, such as high bulk modulus drilling mud, is disposed within the annulus. The vibrational source forms a fluid coupling with the tubular member through the fluid medium to transfer vibrational energy to the tubular member. The vibrational energy may be used, for example, to free a stuck tubular, consolidate a cement slurry and/or detect voids within a cement slurry prior to the curing thereof.

  8. Peri-prosthetic fracture vibration testing

    Energy Technology Data Exchange (ETDEWEB)

    Cruce, Jesse R [Los Alamos National Laboratory; Erwin, Jenny R [Los Alamos National Laboratory; Remick, Kevin R [Los Alamos National Laboratory; Cornwell, Phillip J [Los Alamos National Laboratory; Menegini, R. Michael [INDIANA UNIV.; Racanelli, Joe [STRYKER ORTHOPARDICS

    2010-11-08

    The purpose of this study was to establish a test setup and vibration analysis method to predict femoral stem seating and prevent bone fracture using accelerometer and force response data from an instrumented stem and impactor. This study builds upon earlier studies to identify a means to supplement a surgeon's tactile and auditory senses by using damage identification techniques normally used for civil and mechanical structures. Testing was conducted using foam cortical shell sawbones prepared for stems of different geometries. Each stem was instrumented with an accelerometer. Two impactor designs were compared: a monolithic impactor and a two-piece impactor, each with an integrated load cell and accelerometer. Acceleration and force measurements were taken in the direction of impaction. Comparisons between different methods of applying an impacting force were made, including a drop tower and a surgical hammer. The effect of varying compliance on the data was also investigated. The ultimate goal of this study was to assist in the design of an integrated portable data acquisition system capable of being used in future cadaveric testing. This paper will discuss the experimental setup and the subsequent results of the comparisons made between impactors, prosthetic geometries, compliances, and impact methods. The results of this study can be used for both future replicate testing as well as in a cadaveric environment.

  9. The influence of seat backrest angle on human performance during whole-body vibration.

    Science.gov (United States)

    Paddan, G S; Holmes, S R; Mansfield, N J; Hutchinson, H; Arrowsmith, C I; King, S K; Jones, R J M; Rimell, A N

    2012-01-01

    This study investigated the effects of reclined backrest angles on cognitive and psycho-motor tasks during exposure to vertical whole-body vibration. Twenty participants were each exposed to three test stimuli of vertical vibration: 2-8 Hz; 8-14 Hz and 14-20 Hz, plus a stationary control condition whilst seated on a vibration platform at five backrest angles: 0° (recumbent, supine) to 90° (upright). The vibration magnitude was 2.0 ms(-2) root-mean-square. The participants were seated at one of the backrest angles and exposed to each of the three vibration stimuli while performing a tracking and choice reaction time tasks; then they completed the NASA-TLX workload scales. Apart from 22.5° seat backrest angle for the tracking task, backrest angle did not adversely affect the performance during vibration. However, participants required increased effort to maintain performance during vibration relative to the stationary condition. These results suggest that undertaking tasks in an environment with vibration could increase workload and risk earlier onset of fatigue. Current vibration standards provide guidance for assessing exposures for seated, standing and recumbent positions, but not for semi-recumbent postures. This paper reports new experimental data systematically investigating the effect of backrest angle on human performance. It demonstrates how workload is elevated with whole-body vibration, without getting affected by backrest angle.

  10. Performance and Vibration Analyses of Lift-Offset Helicopters

    Directory of Open Access Journals (Sweden)

    Jeong-In Go

    2017-01-01

    Full Text Available A validation study on the performance and vibration analyses of the XH-59A compound helicopter is conducted to establish techniques for the comprehensive analysis of lift-offset compound helicopters. This study considers the XH-59A lift-offset compound helicopter using a rigid coaxial rotor system as a verification model. CAMRAD II (Comprehensive Analytical Method of Rotorcraft Aerodynamics and Dynamics II, a comprehensive analysis code, is used as a tool for the performance, vibration, and loads analyses. A general free wake model, which is a more sophisticated wake model than other wake models, is used to obtain good results for the comprehensive analysis. Performance analyses of the XH-59A helicopter with and without auxiliary propulsion are conducted in various flight conditions. In addition, vibration analyses of the XH-59A compound helicopter configuration are conducted in the forward flight condition. The present comprehensive analysis results are in good agreement with the flight test and previous analyses. Therefore, techniques for the comprehensive analysis of lift-offset compound helicopters are appropriately established. Furthermore, the rotor lifts are calculated for the XH-59A lift-offset compound helicopter in the forward flight condition to investigate the airloads characteristics of the ABC™ (Advancing Blade Concept rotor.

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

    NARCIS (Netherlands)

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

    2011-01-01

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

  12. Random Vibration Testing of Advanced Wet Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2015-01-01

    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.

  13. Test Operations Procedure (TOP) 01-2-603 Rotorcraft Laboratory Vibration Test Schedules

    Science.gov (United States)

    2017-06-12

    Final 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Test Operations Procedure (TOP) 01-2-603 Rotorcraft Laboratory Vibration Test Schedules...This TOP provides Laboratory Vibration Test Schedules (LVTS) for selected rotary wing aircraft. The LVTS presented in this TOP were developed from... vibration environment of a given rotary wing platform in a laboratory setting. 15. SUBJECT TERMS Laboratory Vibration Test Schedule (LVTS

  14. Vibration or balance training on neuromuscular performance in osteopenic women.

    Science.gov (United States)

    Stolzenberg, N; Belavý, D L; Rawer, R; Felsenberg, D

    2013-11-01

    Maintaining neuromuscular function in older age is an important topic for aging societies, especially for older women with low bone density who may be at risk of falls and bone fracture. This randomized controlled trial investigated the effect of resistive exercise with either whole-body vibration training (VIB) or coordination/balance training (BAL) on neuromuscular function (countermovement jump, multiple 1-leg hopping, sit-to-stand test). 68 postmenopausal women with osteopenia or osteoporosis were recruited for the study. 57 subjects completed the 9-month, twice weekly, intervention period. All subjects conducted 30 min of resistance exercise each training day. The VIB-group performed additional training on the Galileo vibration exercise device. The BAL-group performed balance training. An "intent-to-treat" analysis showed greater improvement in the VIB-group for peak countermovement power (p=0.004). The mean [95% confidence interval] effect size for this parameter was a  + 0.9[0.3 to 1.5] W/kg greater change in VIB than BAL after 9 months. In multiple 1-leg hopping, a significantly better performance in the VIB-group after the intervention period was seen on a "per-protocol" analysis only. Both groups improved in the sit-to-stand test. The current study provides evidence that short-duration whole-body vibration exercise can have a greater impact on some aspects of neuromuscular function in post-menopausal women with low bone density than proprioceptive training. © Georg Thieme Verlag KG Stuttgart · New York.

  15. Vibration-based testing of bolted joints

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Sah, Si Mohamed; Fidlin, Alexander

    2017-01-01

    In recent pilot studies we have started investigating how to possibly use measured flexural (i.e. transverse/bending) vibrations, induced by bolt-tapping, to estimate bolt tightness. Some of the vibration features we investigated showed strong correlation with bolt tightness. For example, the low...... to bolt tension, but also to slenderness ratio. Thus, if only the natural frequency feature were to be used for estimating bolt tension, accuracy will drop off for the short and thick bolts that are often used in critical joints....

  16. Design of a Maglev Vibration Test Platform for the Research of Maglev Vehicle-girder Coupled Vibration Problem

    Directory of Open Access Journals (Sweden)

    Zhou Danfeng

    2017-01-01

    Full Text Available The maglev vehicle-girder coupled vibration problem has been encountered in many maglev test or commercial lines, which significantly degrade the performance of the maglev train. In previous research on the principle of the coupled vibration problem, it has been discovered that the fundamental model of the maglev girder can be simplified as a series of mass-spring resonators of different but related resonance frequencies, and that the stability of the vehicle-girder coupled system can be investigated by separately examining the stability of each mass-spring resonator – electromagnet coupled system. Based on this conclusion, a maglev test platform, which includes a single electromagnetic suspension control system, is built for experimental study of the coupled vibration problem. The guideway of the test platform is supported by a number of springs so as to change its flexibility. The mass of the guideway can also be changed by adjusting extra weights attached to it. By changing the flexibility and mass of the guideway, the rules of the maglev vehicle-girder coupled vibration problem are to be examined through experiments, and related theory on the vehicle-girder self-excited vibration proposed in previous research is also testified.

  17. Chatter vibrations of high-performance motorcycles

    Science.gov (United States)

    Sharp, R. S.; Watanabe, Y.

    2013-03-01

    Motorcycle racing teams occasionally experience speed-limiting vibrations of around 25 Hz frequency in mid-corner. The nature of the vibrations has not been closely defined yet and the mechanics are currently not properly understood. Conventional motorcycle-dynamics models are shown here to reveal the existence of a vibration mode that aligns with the experience being referred to, suggesting some explanations. Root loci for variations in speed or cornering vigour, demonstrating modal characteristics for small perturbations from trim states, are employed to indicate how the mode responds to changes in operation and design. Modal participation is examined for a lightly damped case. Influences on the natural frequency and damping of the mode are found and a way of stabilising the mode is suggested.

  18. SDBI 1904: Human Factors Assessment of Vibration Effects on Visual Performance during Launch

    Science.gov (United States)

    Thompson, Shelby G.; Holden, Kritina; Root, Phillip; Ebert, Douglas; Jones, Jeffery; Adelstein, Bernard

    2009-01-01

    The primary objective of the of Human Factors Short Duration Bioastronautics Investigation (SDBI) 1904 is to determine visual performance limits during operational vibration and g-loads, specifically through the determination of minimal usable font sized using Orion-type display formats. Currently there is little to no data available to quantify human visual performance under these extreme conditions. Existing data on shuttle vibration magnitude and frequency is incomplete, does not address sear and crew vibration in the current configuration, and does not address human visual performance. There have been anecdotal reports of performance decrements from shuttle crews, but no structured data has been collected. The SDBI is a companion effort to the Detailed Test Objective (DTO) 695, which will measure shuttle seat accelerations (vibration) during ascent. Data fro the SDBI will serve an important role in interpreting the DTO vibration data. This data will be collected during the ascent phase of three shuttle missions (STS-119, 127, and 128). Both SDBI1904 and DTO 695 are low impact with respect to flight resources, and combined they represent an efficient and focused problem solving approach. The SDBI and DTO data will be correlated to determine the nature of perceived visual performance under varying vibrations and g-loads. This project will provide: 1) Immediate data for developing preliminary human performance vibration requirements; 2) Flight validated inputs for ongoing and future ground-based research; and 3) Information of functional needs that will drive Orion display format design decisions.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-10-01

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

  20. FIVPET Flow-Induced Vibration Test Report (1) - Candidate Spacer Grid Type I (Optimized H Type)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Hee; Kang, Heung Seok; Yoon, Kyung Ho; Song, Kee Nam; Kim, Jae Yong

    2006-03-15

    The flow-induced vibration (FIV) test using a 5x5 partial fuel assembly was performed to evaluate mechanical/structural performance of the candidate spacer grid type I (Optimized H shape). From the measured vibration response of the test bundle and the flow parameters, design features of the spacer strap can be analyzed in the point of vibration and hydraulic aspect, and also compared with other spacer strap in simple comparative manner. Furthermore, the FIV test will contributes to understand behaviors of nuclear fuel in operating reactor. The FIV test results will be used to verify the theoretical model of fuel rod and assembly vibration. The aim of this report is to present the results of the FIV test of partial fuel assembly and to introduce the detailed test methodology and analysis procedure. In chapter 2, the overall configuration of test bundle and instrumented tube is remarked and chapter 3 will introduce the test facility (FIVPET) and test section. Chapter 4 deals with overall test condition and procedure, measurement and data acquisition devices, instrumentation equipment and calibration, and error analysis. Finally, test result of vibration and pressure fluctuation is presented and discussed in chapter 5.

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

    Science.gov (United States)

    Segerink, F. B.; Korterik, J. P.; Offerhaus, H. L.

    2011-06-01

    This article demonstrates a quick and easy way of quantifying the performance of a vibration-isolated platform. We measure the vibration transfer from floor to table using background noise excitation from the floor. As no excitation device is needed, our setup only requires two identical sensors (in our case, low noise accelerometers), a data acquisition system, and processing software. Background noise excitation from the floor has the additional advantage that any non-linearity in the suspension system relevant to the actual vibration amplitudes will be taken into account. Measurement time is typically a few minutes, depending on the amount of background noise. The (coherent) transfer of the vibrations in the floor to the platform, as well as the (non-coherent) acoustical noise pick-up by the platform are measured. Since we use calibrated sensors, the absolute value of the vibration levels is established and can be expressed in vibration criterion curves. Transfer measurements are shown and discussed for two pneumatic isolated optical tables, a spring suspension system, and a simple foam suspension system.

  2. Development of seismic technology and reliability based on vibration tests

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Youichi [Nuclear Power Engineering Corp., Tokyo (Japan)

    1997-03-01

    This paper deals with some of the vibration tests and investigations on the seismic safety of nuclear power plants (NPPs) in Japan. To ensure the reliability of the seismic safety of nuclear power plants, nuclear power plants in Japan have been designed according to the Technical Guidelines for Aseismic Design of Nuclear Power Plants. This guideline has been developed based on technical date base and findings which were obtained from many vibration tests and investigations. Besides the tests for the guideline, proving tests on seismic reliability of operating nuclear power plants equipment and systems have been carried out. In this paper some vibration tests and their evaluation results are presented. They have crucially contributed to develop the guideline. (J.P.N.)

  3. Time-varying output performances of piezoelectric vibration energy harvesting under nonstationary random vibrations

    Science.gov (United States)

    Yoon, Heonjun; Kim, Miso; Park, Choon-Su; Youn, Byeng D.

    2018-01-01

    Piezoelectric vibration energy harvesting (PVEH) has received much attention as a potential solution that could ultimately realize self-powered wireless sensor networks. Since most ambient vibrations in nature are inherently random and nonstationary, the output performances of PVEH devices also randomly change with time. However, little attention has been paid to investigating the randomly time-varying electroelastic behaviors of PVEH systems both analytically and experimentally. The objective of this study is thus to make a step forward towards a deep understanding of the time-varying performances of PVEH devices under nonstationary random vibrations. Two typical cases of nonstationary random vibration signals are considered: (1) randomly-varying amplitude (amplitude modulation; AM) and (2) randomly-varying amplitude with randomly-varying instantaneous frequency (amplitude and frequency modulation; AM-FM). In both cases, this study pursues well-balanced correlations of analytical predictions and experimental observations to deduce the relationships between the time-varying output performances of the PVEH device and two primary input parameters, such as a central frequency and an external electrical resistance. We introduce three correlation metrics to quantitatively compare analytical prediction and experimental observation, including the normalized root mean square error, the correlation coefficient, and the weighted integrated factor. Analytical predictions are in an excellent agreement with experimental observations both mechanically and electrically. This study provides insightful guidelines for designing PVEH devices to reliably generate electric power under nonstationary random vibrations.

  4. Enhancement of rowing performance in athletes after focal muscle vibration therapy

    Directory of Open Access Journals (Sweden)

    Francesca Grasso

    2017-06-01

    Full Text Available Muscle vibration has been reported to induce long lasting effects on proprioception when applied on specific body segment. The aim of this study was to evaluate the effect of focal muscle vibration applied on quadriceps and latissimus dorsi muscles in athletes evaluate during rowing test. Sixteen volunteered national level sculling stroke rowers has been randomized in a study group and in a control group (treated with sham vibration. The overall kinematic consistency, joints angular acceleration patterns and performance test has been used as evaluation. Results showed statistical significant values for angular accelerations at the knee and shoulder joints and significant effect of the time course of the trial. Vibration treatment seems to be an useful proprioceptive stimulation in sport activities to improve muscle control and performance.

  5. Textiles Performance Testing Facilities

    Data.gov (United States)

    Federal Laboratory Consortium — The Textiles Performance Testing Facilities has the capabilities to perform all physical wet and dry performance testing, and visual and instrumental color analysis...

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

    Directory of Open Access Journals (Sweden)

    Polat Sendur

    2017-01-01

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

  7. Random vibration test of Mars Exploration Rover spacecraft

    Science.gov (United States)

    Scharton, T.; Lee, D.

    2003-01-01

    The primary objective of the random vibration test was to identify any hardware problems, which might compromise the mission. The test objectives, configuration, and requirements are briefly described in this presentation, and a representative sample of the measured data is presented.

  8. 49 CFR Appendix C to Part 173 - Procedure for Base-level Vibration Testing

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Procedure for Base-level Vibration Testing C... Base-level Vibration Testing Base-level vibration testing shall be conducted as follows: 1. Three... platform. 4. Immediately following the period of vibration, each package shall be removed from the platform...

  9. Vibration Testing of NASA's Time Machine Near-Infrared Spectrograph

    Science.gov (United States)

    Jentsch, M.; Knecht, M.; Jollet, D.; Kommer, A.

    2014-06-01

    "NASA, ESA, and the Canadian Space Agency (CSA) are collaborating to develop JWST, a successor to the Hubble Space Telescope and enable observation and measurement of infrared wavelengths. JWST will be able to study every phase in the evolution of the Universe in great detail - from the first stars and galaxies to form after the Big Bang to the formation of planetary systems in our own Milky Way galaxy today. This will be made possible by JWST's huge primary mirror (which, with 18 hexagonal segments spanning a total of six and a half metres in diameter, will be the largest telescope in space) and its suite of four highly- sensitive scientific instruments, one of which is NIRSpec, able to detect the faintest radiation from the most distant galaxies.Mostly made from silicon carbide (SiC100), NIRSpec weighs only 200 kilograms and will operate at temperatures of -233°C as JWST orbits 1.5 million kilometres away from Earth. Once in space, the telescope and its instruments will remain in operation for up to 10 years." [4]The NIRSpec Optical Assembly consists of a ceramic optical bench supported by a set of hybrid kinematic mounts, several high performance optical subassemblies (e.g. the three mirror anastigmats (TMAs) also made of silicon carbide), mechanisms and a micro shutter assembly (MSA) which allows a detailed selection of at least 100 objects simultaneously at various spectral resolutions.Besides many other environmental testing the structural mechanics test campaign was divided into two parts. The qualification has been performed with the ETU (engineering test unit) consisting of the optical bench including the mounts and all ceramic parts in flight like configuration. A part of the subassemblies has been substituted by flight representative design models. Sine and random vibration qualification runs in three spatial axes have been performed to fulfil the requirements derived for the spacecraft configuration to cover Ariane 5 launch loads and the JWST program

  10. Design and Test of Semi-Active Vibration-Reducing System for Lathe

    Directory of Open Access Journals (Sweden)

    Hongsheng Hu

    2014-09-01

    Full Text Available In this paper, its theory design, analysis and test system of semi-active vibration controlling system used for precision machine have been done. Firstly, lathe bed and spindle entity were modeled by using UG software; Then modes of the machine bed and the key components of spindle were obtained by using ANSYS software; Finally, harmonic response analysis of lathe spindle under complex load was acquired, which provided a basis of MR damper’s structure optimization design for a certain type of precision machine. In order to prove its effectives, a prototype semi-active vibration controlling lathe with MR damper was developed. Tests have been done, and comparison results between passive vibration isolation equipment and semi-active vibration controlling equipment proved its good performances of MR damper.

  11. Local vibrations and lift performance of low Reynolds number airfoil

    Directory of Open Access Journals (Sweden)

    TariqAmin Khan

    2017-06-01

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

  12. Short Duration Bioastronautics Investigation 1904: Human Factors Assessment of Vibration Effects on Visual Performance during Launch

    Science.gov (United States)

    Thompson, Shelby; Holden, Kritina; Ebert, Douglas; Root, Phillip; Adelstein, Bernard; Jones, Jeffery

    2009-01-01

    The primary objective of the Short Duration Bioastronautics Investigation (SDBI) 1904 was to determine visual performance limits during Shuttle operational vibration and g-loads, specifically through the determination of minimal usable font sizes using Orion-type display formats. Currently there is little to no data available to quantify human visual performance under the extreme g- and vibration conditions of launch. Existing data on shuttle vibration magnitude and frequency is incomplete and does not address human visual performance. There have been anecdotal reports of performance decrements from shuttle crews, but no structured data have been collected. Previous work by NASA on the effects of vibration and linear g-loads on human performance was conducted during the Gemini era, but these experiments were performed using displays and controls that are dramatically different than current concepts being considered by the Constellation Program. Recently, three investigations of visual performance under vibration have been completed at NASA Ames Research Center: the first examining whole-body vibration, the second employing whole-body vibration coupled with a sustained g-load, and a third examining the effects of peak versus extended duration vibration. However, all of these studies were conducted using only a single x-axis direction (eyeballs in/out). Estimates of thrust oscillations from the Constellation Ares-I first stage are driving the need for realistic human performance requirements. SDBI 1904 was an opportunity to address the need for requirements by conducting a highly focused and applied evaluation in a relevant spaceflight environment. The SDBI was a companion effort to Detailed Test Objective (DTO) 695, which measured shuttle seat accelerations (vibration) during ascent. Data from the SDBI will serve an important role in interpreting the DTO vibration data. Both SDBI 1904 and DTO 695 were low impact with respect to flight resources, and combined, they

  13. Technical Road Testing of the 18,000 BTU Air Conditioners (Vibration Profile)

    Science.gov (United States)

    1990-06-27

    equimped with a calibrated fifth wheel driven speedanetr. Instrumented testing was crducted on the Mzso area izproved gravel road, Belgian block, two...item, conducting the test, and acquiring and processing all test data. 1.5 SYSTEM DESCRIPTION Two 50/60 Hz, 3-2hase, 208-volt, 18,000 BTU/hr compact...operationally checked periodically and at the conclusion of the road vibration test. A limited amount of data processing was performed at the test

  14. Performance evaluation on vibration control of MR landing gear

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D Y; Nam, Y J; Park, M K [Graduate School, Pusan National University, Busan 609-735 (Korea, Republic of); Yamane, R [Kokushikan University, 4-28-1 Setagaya, Setagaya-ku, Tokyo 154-8515 (Japan)], E-mail: ldy5577@yahoo.co.kr, E-mail: mkpark1@pusan.ac.kr

    2009-02-01

    This paper is concerned with the applicability of the developed MR damper to the landing gear system for the attenuating undesired shock and vibration in the landing and taxing phases. First of all, the experimental model of the MR damper is derived based on the results of performance evaluations. Next, a simplified skyhook controller, which is one of the most straightforward, but effective approaches for improving ride comport in vehicles with active suspensions, is formulated. Then, the vibration control performances of the landing gear system using the MR damper are theoretically evaluated in the landing phase of the aircraft. A series of simulation analyses show that the proposed MR damper with the skyhook controller is effective for suppressing undesired vibration of the aircraft body. Finally, the effectiveness of the simulation results are additionally verified via HILS (Hardware-in-the-loop-simulation) method.

  15. Investigation of Gearbox Vibration Transmission Paths on Gear Condition Indicator Performance

    Science.gov (United States)

    Dempsey, Paula J.; Islam, AKM Anwarul; Feldman, Jason; Larsen, Chris

    2013-01-01

    Helicopter health monitoring systems use vibration signatures generated from damaged components to identify transmission faults. For damaged gears, these signatures relate to changes in dynamics due to the meshing of the damaged tooth. These signatures, referred to as condition indicators (CI), can perform differently when measured on different systems, such as a component test rig, or a full-scale transmission test stand, or an aircraft. These differences can result from dissimilarities in systems design and environment under dynamic operating conditions. The static structure can also filter the response between the vibration source and the accelerometer, when the accelerometer is installed on the housing. To assess the utility of static vibration transfer paths for predicting gear CI performance, measurements were taken on the NASA Glenn Spiral Bevel Gear Fatigue Test Rig. The vibration measurements were taken to determine the effect of torque, accelerometer location and gearbox design on accelerometer response. Measurements were taken at the housing and compared while impacting the gear set near mesh. These impacts were made at gear mesh to simulate gear meshing dynamics. Data measured on a helicopter gearbox installed in a static fixture were also compared to the test rig. The behavior of the structure under static conditions was also compared to CI values calculated under dynamic conditions. Results indicate that static vibration transfer path measurements can provide some insight into spiral bevel gear CI performance by identifying structural characteristics unique to each system that can affect specific CI response.

  16. On Modal Parameter Estimates from Ambient Vibration Tests

    DEFF Research Database (Denmark)

    Agneni, A.; Brincker, Rune; Coppotelli, B.

    2004-01-01

    Modal parameter estimates from ambient vibration testing are turning into the preferred technique when one is interested in systems under actual loadings and operational conditions. Moreover, with this approach, expensive devices to excite the structure are not needed, since it can be adequately...

  17. An equipment test for grading lumber by transverse vibration technique

    Directory of Open Access Journals (Sweden)

    Marcelo Rodrigo Carreira

    2008-08-01

    Full Text Available Due to the great variability of its mechanical properties, the rational use of lumber for structural purposes is directly conditioned to its grading. There are several techniques available for grading structural lumber. The most relevant one is the transverse vibration technique which obtained reliable results in non-destructive evaluation of lumber. The purpose of this work is to present the bases for the mechanical grading of lumber and the results of the calibration test of the frst transverse vibration equipment developed in Brazil. In this research 30 beams of cupiúba (Goupia glabra with nominal dimensions of 5 cm X 10 cm X 300 cm, were used. The tests were accomplished at the Wood and Timber Structures Laboratory (LaMEM of the University of São Paulo (USP. The results showed a strong correlation between the elasticity modulus measured by the static bending test and the one obtained with the transverse vibration equipment, showing the high reliability of the vibration method for the grading of structural lumber. A determination coeffcient (R² of 0.896 was obtained with the Brazilian equipment, showing that it can be used in the grading of lumber.

  18. Design of an Ultrasonic Elliptic-Vibration Shoe and Its Performance in Ultrasonic Elliptic-Vibration-Shoe Centerless Grinding

    Science.gov (United States)

    Fan, Yufeng; Wu, Yongbo; Kato, Masana; Tachibana, Toru; Syoji, Katsuo; Kuriyagawa, Tsunemoto

    We describe the design of an ultrasonic elliptic-vibration shoe and its performance in ultrasonic elliptic-vibration-shoe centerless grinding. First, the vibration modes of the shoe for the bending and longitudinal directions are discussed and determined from the point of view of fixing the support of the shoe. Then the structure and dimensions of the shoe are determined by FEM (Finite Element Method) analysis. In order to clarify the performance of the produced shoe, an evaluation apparatus is built. The elliptic motions under different applied voltages are investigated using laser vibrometers. Finally, workpiece rotational motion control tests and actual grinding operations are carried out. As a result, it is clarified that the workpiece rotational speed changes linearly with variation of the applied voltage. This indicates that the workpiece rotational motion can be precisely controlled by the elliptic motion of the shoe. In addition, the workpiece roundness was clearly improved from an initial value of 25µm to a final value of 0.64µm after grinding, indicating that the produced shoe performed well in actual grinding operations.

  19. A New Large Vibration Test Facility Concept for the James Webb Space Telescope

    Science.gov (United States)

    Ross, Brian P.; Johnson, Eric L.; Hoksbergen, Joel; Lund, Doug

    2014-01-01

    The James Webb Space Telescope consists of three main components, the Integrated Science Instrument Module (ISIM) Element, the Optical Telescope Element (OTE), and the Spacecraft Element. The ISIM and OTE are being assembled at the National Aeronautics and Space Administration's Goddard Spaceflight Center (GSFC). The combined OTE and ISIM Elements, called OTIS, will undergo sine vibration testing before leaving Goddard. OTIS is the largest payload ever tested at Goddard and the existing GSFC vibration facilities are incapable of performing a sine vibration test of the OTIS payload. As a result, a new large vibration test facility is being designed. The new facility will consist of a vertical system with a guided head expander and a horizontal system with a hydrostatic slip table. The project is currently in the final design phase with installation to begin in early 2015 and the facility is expected to be operational by late 2015. This paper will describe the unique requirements for a new large vibration test facility and present the selected final design concepts.

  20. Real-Time Performance of Mechatronic PZT Module Using Active Vibration Feedback Control.

    Science.gov (United States)

    Aggogeri, Francesco; Borboni, Alberto; Merlo, Angelo; Pellegrini, Nicola; Ricatto, Raffaele

    2016-09-25

    This paper proposes an innovative mechatronic piezo-actuated module to control vibrations in modern machine tools. Vibrations represent one of the main issues that seriously compromise the quality of the workpiece. The active vibration control (AVC) device is composed of a host part integrated with sensors and actuators synchronized by a regulator; it is able to make a self-assessment and adjust to alterations in the environment. In particular, an innovative smart actuator has been designed and developed to satisfy machining requirements during active vibration control. This study presents the mechatronic model based on the kinematic and dynamic analysis of the AVC device. To ensure a real time performance, a H2-LQG controller has been developed and validated by simulations involving a machine tool, PZT actuator and controller models. The Hardware in the Loop (HIL) architecture is adopted to control and attenuate the vibrations. A set of experimental tests has been performed to validate the AVC module on a commercial machine tool. The feasibility of the real time vibration damping is demonstrated and the simulation accuracy is evaluated.

  1. Performance evaluation of full-scale tuned liquid dampers (TLDs) for vibration control of large wind turbines using real-time hybrid testing

    DEFF Research Database (Denmark)

    Zhang, Zili; Staino, Andrea; Basu, Biswajit

    2016-01-01

    Highlights •Performance evaluation of full-scale tuned liquid dampers carried out for wind turbines. •Coupled blade-tower model considered in the numerical sub-structure. •Stochastic turbulence due to rotationally sampled spectra considered. •Effect of damping screens experimentally investigated...

  2. Modal confidence factor in vibration testing

    Science.gov (United States)

    Ibrahim, S. R.

    1978-01-01

    The modal confidence factor (MCF) is a number calculated for every identified mode for a structure under test. The MCF varies from 0.00 for a distorted nonlinear, or noise mode to 100.0 for a pure structural mode. The theory of the MCF is based on the correlation that exists between the modal deflection at a certain station and the modal deflection at the same station delayed in time. The theory and application of the MCF are illustrated by two experiments. The first experiment deals with simulated responses from a two-degree-of-freedom system with 20%, 40%, and 100% noise added. The second experiment was run on a generalized payload model. The free decay response from the payload model contained 22% noise.

  3. Performance of active vibration control technology: the ACTEX flight experiments

    Science.gov (United States)

    Nye, T. W.; Manning, R. A.; Qassim, K.

    1999-12-01

    This paper discusses the development and results of two intelligent structures space-flight experiments, each of which could affect architecture designs of future spacecraft. The first, the advanced controls technology experiment I (ACTEX I), is a variable stiffness tripod structure riding as a secondary payload on a classified spacecraft. It has been operating well past its expected life since becoming operational in 1996. Over 60 on-orbit experiments have been run on the ACTEX I flight experiment. These experiments form the basis for in-space controller design problems and for concluding lifetime/reliability data on the active control components. Transfer functions taken during the life of ACTEX I have shown consistent predictability and stability in structural behavior, including consistency with those measurements taken on the ground prior to a three year storage period and the launch event. ACTEX I can change its modal characteristics by employing its dynamic change mechanism that varies preloads in portions of its structure. Active control experiments have demonstrated maximum vibration reductions of 29 dB and 16 dB in the first two variable modes of the system, while operating over a remarkable on-orbit temperature range of -80 °C to 129 °C. The second experiment, ACTEX II, was successfully designed, ground-tested, and integrated on an experimental Department of Defense satellite prior to its loss during a launch vehicle failure in 1995. ACTEX II also had variable modal behavior by virtue of a two-axis gimbal and added challenges of structural flexibility by being a large deployable appendage. Although the loss of ACTEX II did not provide space environment experience, ground testing resulted in space qualifying the hardware and demonstrated 21 dB, 14 dB, and 8 dB reductions in amplitude of the first three primary structural modes. ACTEX II could use either active and/or passive techniques to affect vibration suppression. Both experiments trailblazed

  4. 30 CFR 27.39 - Tests to determine resistance to vibration.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests to determine resistance to vibration. 27... determine resistance to vibration. (a) Laboratory tests for reliability and durability. Components... two separate vibration tests, each of one-hour duration. The first test shall be conducted at a...

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

    Science.gov (United States)

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

    2015-01-01

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

  6. A Coupling Vibration Test Bench and the Simulation Research of a Maglev Vehicle

    Directory of Open Access Journals (Sweden)

    Weihua Ma

    2015-01-01

    Full Text Available To study the characteristics of the coupling vibration between a maglev vehicle and its track beam system and to improve the performance of the levitation system, a new type of vibration test bench was developed. Take a single maglev frame as the study object; simulation of the coupling vibration of the maglev vehicle, levitation system, and track beam were achieved. In addition, all types of real track irregularity excitations can be simulated using hydraulic actuators of the test bench. To expand the research scope, a simulation model was developed that can conduct the simulation research synergistically with the test bench. Based on a dynamics model of the test bench, the dynamics simulation method determined the influence on the levitation control performance of three factors: the track beam support stiffness, the track beam mass, and the track irregularity. The vibration resonance phenomenon of the vehicle/track system was reproduced by the dynamics simulation, and a portion of the simulation results were validated by the test results. By combining the test bench and the dynamics model, experiments can be guided by the simulation results, and the experimental results can validate the dynamics simulation results.

  7. Adaptive and robust active vibration control methodology and tests

    CERN Document Server

    Landau, Ioan Doré; Castellanos-Silva, Abraham; Constantinescu, Aurelian

    2017-01-01

    This book approaches the design of active vibration control systems from the perspective of today’s ideas of computer control. It formulates the various design problems encountered in the active management of vibration as control problems and searches for the most appropriate tools to solve them. The experimental validation of the solutions proposed on relevant tests benches is also addressed. To promote the widespread acceptance of these techniques, the presentation eliminates unnecessary theoretical developments (which can be found elsewhere) and focuses on algorithms and their use. The solutions proposed cannot be fully understood and creatively exploited without a clear understanding of the basic concepts and methods, so these are considered in depth. The focus is on enhancing motivations, algorithm presentation and experimental evaluation. MATLAB®routines, Simulink® diagrams and bench-test data are available for download and encourage easy assimilation of the experimental and exemplary material. Thre...

  8. Fixed Base Modal Testing Using the NASA GRC Mechanical Vibration Facility

    Science.gov (United States)

    Staab, Lucas D.; Winkel, James P.; Suarez, Vicente J.; Jones, Trevor M.; Napolitano, Kevin L.

    2016-01-01

    The Space Power Facility at NASA's Plum Brook Station houses the world's largest and most powerful space environment simulation facilities, including the Mechanical Vibration Facility (MVF), which offers the world's highest-capacity multi-axis spacecraft shaker system. The MVF was designed to perform sine vibration testing of a Crew Exploration Vehicle (CEV)-class spacecraft with a total mass of 75,000 pounds, center of gravity (cg) height above the table of 284 inches, diameter of 18 feet, and capability of 1.25 gravity units peak acceleration in the vertical and 1.0 gravity units peak acceleration in the lateral directions. The MVF is a six-degree-of-freedom, servo-hydraulic, sinusoidal base-shake vibration system that has the advantage of being able to perform single-axis sine vibration testing of large structures in the vertical and two lateral axes without the need to reconfigure the test article for each axis. This paper discusses efforts to extend the MVF's capabilities so that it can also be used to determine fixed base modes of its test article without the need for an expensive test-correlated facility simulation.

  9. Acoustically Induced Vibration of Structures: Reverberant Vs. Direct Acoustic Testing

    Science.gov (United States)

    Kolaini, Ali R.; O'Connell, Michael R.; Tsoi, Wan B.

    2009-01-01

    Large reverberant chambers have been used for several decades in the aerospace industry to test larger structures such as solar arrays and reflectors to qualify and to detect faults in the design and fabrication of spacecraft and satellites. In the past decade some companies have begun using direct near field acoustic testing, employing speakers, for qualifying larger structures. A limited test data set obtained from recent acoustic tests of the same hardware exposed to both direct and reverberant acoustic field testing has indicated some differences in the resulting structural responses. In reverberant acoustic testing, higher vibration responses were observed at lower frequencies when compared with the direct acoustic testing. In the case of direct near field acoustic testing higher vibration responses appeared to occur at higher frequencies as well. In reverberant chamber testing and direct acoustic testing, standing acoustic modes of the reverberant chamber or the speakers and spacecraft parallel surfaces can strongly couple with the fundamental structural modes of the test hardware. In this paper data from recent acoustic testing of flight hardware, that yielded evidence of acoustic standing wave coupling with structural responses, are discussed in some detail. Convincing evidence of the acoustic standing wave/structural coupling phenomenon will be discussed, citing observations from acoustic testing of a simple aluminum plate. The implications of such acoustic coupling to testing of sensitive flight hardware will be discussed. The results discussed in this paper reveal issues with over or under testing of flight hardware that could pose unanticipated structural and flight qualification issues. Therefore, it is of paramount importance to understand the structural modal coupling with standing acoustic waves that has been observed in both methods of acoustic testing. This study will assist the community to choose an appropriate testing method and test setup in

  10. Testing of Tools for Measurement Vibration in Car

    Directory of Open Access Journals (Sweden)

    Martin JURÁNEK

    2009-06-01

    Full Text Available This work is specialized on testing of several sensors for measurement vibration, that be applicable for measurement on vehicles also behind running. These sensors are connected to PC and universal mobile measuring system cRIO (National Instruments with analog I/O module for measurement vibration, that is described in diploma work: [JURÁNEK 2008]. This system has upped mechanical and heat imunity, small proportions and is therefore acceptable also measurement behind ride vehicles. It compose from two head parts. First is measuring part, composite from instruments cRIO. First part is controlled and monitored by PDA there is connected of wireless (second part hereof system. To system cRIO is possible connect sensors by four BNC connector or after small software change is possible add sensor to other analog modul cRIO. Here will be test several different types of accelerometers (USB sensor company Phidgets, MEMS sensor company Freescale, piezoresistiv and Delta Tron accelerometers company Brüel&Kjær. These sensors is attach to stiff board, board is attach to vibrator and excite by proper signal. Testing will realized with reference to using for measurement in cars. Results will be compared with professional signal analyser LabShop pulse from company Brüel&Kjær.

  11. A General Purpose Digital System for Field Vibration Testing

    OpenAIRE

    Brincker, Rune; Larsen, Jesper Abildgaard; Ventura, Carlos

    2007-01-01

    This paper describes the development and concept implementation of a highly sensitive digital recording system for seismic applications and vibration measurements on large Civil Engineering structures. The system is based on highly sensitive motion transducers that have been used by seismologists and geophysicists for decades. The conventional geophone's ratio of cost to performance, including noise, linearity and dynamic range is unmatched by advanced modern accelerometers. The unit comprise...

  12. Correlation of finite element free vibration predictions using random vibration test data. M.S. Thesis - Cleveland State Univ.

    Science.gov (United States)

    Chambers, Jeffrey A.

    1994-01-01

    Finite element analysis is regularly used during the engineering cycle of mechanical systems to predict the response to static, thermal, and dynamic loads. The finite element model (FEM) used to represent the system is often correlated with physical test results to determine the validity of analytical results provided. Results from dynamic testing provide one means for performing this correlation. One of the most common methods of measuring accuracy is by classical modal testing, whereby vibratory mode shapes are compared to mode shapes provided by finite element analysis. The degree of correlation between the test and analytical mode shapes can be shown mathematically using the cross orthogonality check. A great deal of time and effort can be exhausted in generating the set of test acquired mode shapes needed for the cross orthogonality check. In most situations response data from vibration tests are digitally processed to generate the mode shapes from a combination of modal parameters, forcing functions, and recorded response data. An alternate method is proposed in which the same correlation of analytical and test acquired mode shapes can be achieved without conducting the modal survey. Instead a procedure is detailed in which a minimum of test information, specifically the acceleration response data from a random vibration test, is used to generate a set of equivalent local accelerations to be applied to the reduced analytical model at discrete points corresponding to the test measurement locations. The static solution of the analytical model then produces a set of deformations that once normalized can be used to represent the test acquired mode shapes in the cross orthogonality relation. The method proposed has been shown to provide accurate results for both a simple analytical model as well as a complex space flight structure.

  13. Vibration and Acoustic Test Facility (VATF): User Test Planning Guide

    Science.gov (United States)

    Fantasia, Peter M.

    2011-01-01

    Test process, milestones and inputs are unknowns to first-time users of the VATF. The User Test Planning Guide aids in establishing expectations for both NASA and non-NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware/software developers. It is intended to assist their test engineering personnel in test planning and execution. Material covered includes a roadmap of the test process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, test article interfaces, and inputs necessary to define test scope, cost, and schedule are included as an appendix to the guide.

  14. A procedure obtaining stiffnesses and masses of a structure from vibration modes and substructure static test data

    Science.gov (United States)

    Edighoffer, H. H.

    1979-01-01

    A component mode desynthesis procedure is developed for determining the unknown vibration characteristics of a structural component (i.e., a launch vehicle) given the vibration characteristics of a structural system composed of that component combined with a known one (i.e., a payload). At least one component static test has to be performed. These data are used in conjunction with the system measured frequencies and mode shapes to obtain the vibration characteristics of each component. The flight dynamics of an empty launch vehicle can be determined from measurements made on a vehicle/payload combination in conjunction with a static test on the payload.

  15. Integrated Vehicle Ground Vibration Testing of Manned Spacecraft: Historical Precedent

    Science.gov (United States)

    Lemke, Paul R.; Tuma, Margaret L.; Askins, Bruce R.

    2008-01-01

    For the first time in nearly 30 years, NASA is developing a new manned space flight launch system. The Ares I will carry crew and cargo to not only the International Space Station, but onward for the future exploration of the Moon and Mars. The Ares I control system and structural designs use complex computer models for their development. An Integrated Vehicle Ground Vibration Test (IVGVT) will validate the efficacy of these computer models. The IVGVT will reduce the technical risk of unexpected conditions that could place the vehicle or crew in jeopardy. The Ares Project Office's Flight and Integrated Test Office commissioned a study to determine how historical programs, such as Saturn and Space Shuttle, validated the structural dynamics of an integrated flight vehicle. The study methodology was to examine the historical record and seek out members of the engineering community who recall the development of historic manned launch vehicles. These records and interviews provided insight into the best practices and lessons learned from these historic development programs. The information that was gathered allowed the creation of timelines of the historic development programs. The timelines trace the programs from the development of test articles through test preparation, test operations, and test data reduction efforts. These timelines also demonstrate how the historical tests fit within their overall vehicle development programs. Finally, the study was able to quantify approximate staffing levels during historic development programs. Using this study, the Flight and Integrated Test Office was able to evaluate the Ares I Integrated Vehicle Ground Vibration Test schedule and workforce budgets in light of the historical precedents to determine if the test had schedule or cost risks associated with it.

  16. Induced vibrations increase performance of a winged self-righting robot

    Science.gov (United States)

    Othayoth, Ratan; Xuan, Qihan; Li, Chen

    When upside down, cockroaches can open their wings to dynamically self-right. In this process, an animal often has to perform multiple unsuccessful maneuvers to eventually right, and often flails its legs. Here, we developed a cockroach-inspired winged self-righting robot capable of controlled body vibrations to test the hypothesis that vibrations assist self-righting transitions. Robot body vibrations were induced by an oscillating mass (10% of body mass) and varied by changing oscillation frequency. We discovered that, as the robot's body vibrations increased, righting probability increased, and righting time decreased (P <0.0001, ANOVA), confirming our hypothesis. To begin to understand the underlying physics, we developed a locomotion energy landscape model. Our model revealed that the kinetic energy fluctuations due to vibrations were comparable to the potential energy barriers required to transition from a metastable overturned orientation to an upright orientation. Our study supports the plausibility of locomotion energy landscapes for understanding locomotor transitions, but highlights the need for further stochastic modeling to capture the uncertain nature of when righting maneuvers result in successful righting.

  17. Examples Performance Testing Templates.

    Energy Technology Data Exchange (ETDEWEB)

    Siple, Bud H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-07-01

    The purpose of this Performance Testing Program Plan is to identify the process and phased approach that will be implemented at Site XYZ . The purpose of the testing program at Site XYZ is specifically designed to evaluate the effectiveness of systems that are employed at this site. This plan defines tasks to be accomplished to ensure that performance testing is conducted as effectively and efficiently as possible.

  18. Modal vibration testing of the DVA-1 radio telescope

    Science.gov (United States)

    Byrnes, Peter W. G.; Lacy, Gordon

    2016-07-01

    The Dish Verification Antenna 1 (DVA-1) is a 15m aperture offset Gregorian radio telescope featuring a rim-supported single piece molded composite primary reflector on an altitude-azimuth pedestal mount. Vibration measurements of the DVA-1 telescope were conducted over three days in October 2014 by NSI Herzberg engineers. The purpose of these tests was to measure the first several natural frequencies of the DVA-1 telescope. This paper describes the experimental approach, in particular the step-release method, and summarizes some interesting results, including unexpectedly high damping of the first mode over a narrow range of zenith angles.

  19. A Novel Vibration Mode Testing Method for Cylindrical Resonators Based on Microphones

    Directory of Open Access Journals (Sweden)

    Yongmeng Zhang

    2015-01-01

    Full Text Available Non-contact testing is an important method for the study of the vibrating characteristic of cylindrical resonators. For the vibratory cylinder gyroscope excited by piezo-electric electrodes, mode testing of the cylindrical resonator is difficult. In this paper, a novel vibration testing method for cylindrical resonators is proposed. This method uses a MEMS microphone, which has the characteristics of small size and accurate directivity, to measure the vibration of the cylindrical resonator. A testing system was established, then the system was used to measure the vibration mode of the resonator. The experimental results show that the orientation resolution of the node of the vibration mode is better than 0.1°. This method also has the advantages of low cost and easy operation. It can be used in vibration testing and provide accurate results, which is important for the study of the vibration mode and thermal stability of vibratory cylindrical gyroscopes.

  20. Used fuel rail shock and vibration testing options analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Steven B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Best, Ralph E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Klymyshyn, Nicholas A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jensen, Philip J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Maheras, Steven J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-09-25

    The objective of the rail shock and vibration tests is to complete the framework needed to quantify loads of fuel assembly components that are necessary to guide materials research and establish a technical basis for review organizations such as the U.S. Nuclear Regulatory Commission (NRC). A significant body of experimental and numerical modeling data exists to quantify loads and failure limits applicable to normal conditions of transport (NCT) rail transport, but the data are based on assumptions that can only be verified through experimental testing. The test options presented in this report represent possible paths for acquiring the data that are needed to confirm the assumptions of previous work, validate modeling methods that will be needed for evaluating transported fuel on a case-by-case basis, and inform material test campaigns on the anticipated range of fuel loading. The ultimate goal of this testing is to close all of the existing knowledge gaps related to the loading of used fuel under NCT conditions and inform the experiments and analysis program on specific endpoints for their research. The options include tests that would use an actual railcar, surrogate assemblies, and real or simulated rail transportation casks. The railcar carrying the cradle, cask, and surrogate fuel assembly payload would be moved in a train operating over rail track modified or selected to impart shock and vibration forces that occur during normal rail transportation. Computer modeling would be used to help design surrogates that may be needed for a rail cask, a cask’s internal basket, and a transport cradle. The objective of the design of surrogate components would be to provide a test platform that effectively simulates responses to rail shock and vibration loads that would be exhibited by state-of-the-art rail cask, basket, and/or cradle structures. The computer models would also be used to help determine the placement of instrumentation (accelerometers and strain gauges

  1. Vibration and thermal vacuum qualification test results for a low-voltage tungsten-halogen light

    Science.gov (United States)

    Sexton, J. Andrew

    1991-01-01

    The results of a space flight qualification test program for a low-voltage, quartz tungsten-halogen light are presented. The test program was designed to qualify a halogen light for use in the Pool Boiling Experiment, a Get Away Special (GAS) payload that will be flown in the space shuttle payload bay. Vibration and thermal vacuum tests were performed. The test results indicated that the halogen light will survive the launch and ascent loads, and that the convection-free environment associated with the GAS payload system will not detrimentally affect the operation of the halogen light.

  2. Experimental Design and Validation of an Accelerated Random Vibration Fatigue Testing Methodology

    OpenAIRE

    Yu Jiang(Center for Statistical and Theoretical Condensed Matter Physics, Zhejiang Normal University, Jinhua City, Zhejiang Province 321004, China); Gun Jin Yun; Li Zhao; Junyong Tao

    2015-01-01

    Novel accelerated random vibration fatigue test methodology and strategy are proposed, which can generate a design of the experimental test plan significantly reducing the test time and the sample size. Based on theoretical analysis and fatigue damage model, several groups of random vibration fatigue tests were designed and conducted with the aim of investigating effects of both Gaussian and non-Gaussian random excitation on the vibration fatigue. First, stress responses at a weak point of a ...

  3. Improved orthogonality check for measured modes. [from ground vibration testing of structures

    Science.gov (United States)

    Berman, A.

    1980-01-01

    A method is proposed for performing an orthogonality check for normal modes derived from ground vibration testing. The method utilizes partitioned mass and stiffness matrices for a linear undamped representation of a structure. The normalization of the modes by the proposed method inherently includes the effects of significant displacements which were not measured; and the method may allow the use of fewer measurement points than would be necessary with the conventional method.

  4. Whole body vibration improves attention and motor performance in ...

    African Journals Online (AJOL)

    Background: Whole body vibration (WBV) is a form of physical stimulation via mechanical vibrations transmitted to a subject. It is assumed that WBV induces sensory stimulation in cortical brain regions through the activation of skin and muscle receptors responding to the vibration. The effects of WBV on muscle strength are ...

  5. High Frequency Vibration Based Fatigue Testing of Developmental Alloys

    Science.gov (United States)

    Holycross, Casey M.; Srinivasan, Raghavan; George, Tommy J.; Tamirisakandala, Seshacharyulu; Russ, Stephan M.

    Many fatigue test methods have been previously developed to rapidly evaluate fatigue behavior. This increased test speed can come at some expense, since these methods may require non-standard specimen geometry or increased facility and equipment capability. One such method, developed by George et al, involves a base-excited plate specimen driven into a high frequency bending resonant mode. This resonant mode is of sufficient frequency (typically 1200 to 1700 Hertz) to accumulate 107 cycles in a few hours. One of the main limitations of this test method is that fatigue cracking is almost certainly guaranteed to be surface initiated at regions of high stress. This brings into question the validity of the fatigue test results, as compared to more traditional uniaxial, smooth-bar testing, since high stresses are subjecting only a small volume to fatigue damage. This limitation also brings into question the suitability of this method to screen developmental alloys, should their initiation life be governed by subsurface flaws. However, if applicable, the rapid generation of fatigue data using this method would facilitate faster design iterations, identifying more quickly, material and manufacturing process deficiencies. The developmental alloy used in this study was a powder metallurgy boron-modified Ti-6Al-4V, a new alloy currently being considered for gas turbine engine fan blades. Plate specimens were subjected to fully reversed bending fatigue. Results are compared with existing data from commercially available Ti-6Al-4V using both vibration based and more traditional fatigue test methods.

  6. Theoretical and Numerical Experiences on a Test Rig for Active Vibration Control of Mechanical Systems with Moving Constraints

    Directory of Open Access Journals (Sweden)

    M. Rinchi

    2004-01-01

    Full Text Available Active control of vibrations in mechanical systems has recently benefited of the remarkable development of robust control techniques. These control techniques are able to guarantee performances in spite of unavoidable modeling errors. They have been successfully codified and implemented for vibrating structures whose uncertain parameters could be assumed to be time-invariant. Unfortunately a wide class of mechanical systems, such as machine tools with carriage motion realized by a ball-screw, are characterized by time varying modal parameters. The focus of this paper is on modeling and controlling the vibrations of such systems. A test rig for active vibration control is presented. An analytical model of the test rig is synthesized starting by design data. Through experimental modal analysis, parametric identification and updating procedures, the model has been refined and a control system has been synthesized.

  7. Vibration Durability Testing of Nickel Cobalt Aluminum Oxide (NCA Lithium-Ion 18650 Battery Cells

    Directory of Open Access Journals (Sweden)

    James Michael Hooper

    2016-04-01

    Full Text Available This paper outlines a study undertaken to determine if the electrical performance of Nickel Cobalt Aluminum Oxide (NCA 3.1 Ah 18650 battery cells can be degraded by road induced vibration typical of an electric vehicle (EV application. This study investigates if a particular cell orientation within the battery assembly can result in different levels of cell degradation. The 18650 cells were evaluated in accordance with Society of Automotive Engineers (SAE J2380 standard. This vibration test is synthesized to represent 100,000 miles of North American customer operation at the 90th percentile. This study identified that both the electrical performance and the mechanical properties of the NCA lithium-ion cells were relatively unaffected when exposed to vibration energy that is commensurate with a typical vehicle life. Minor changes observed in the cell’s electrical characteristics were deemed not to be statistically significant and more likely attributable to laboratory conditions during cell testing and storage. The same conclusion was found, irrespective of cell orientation during the test.

  8. COMPARING THE EFFECTS OF VARIOUS WHOLE-BODY VIBRATION ACCELERATIONS ON COUNTER-MOVEMENT JUMP PERFORMANCE

    Directory of Open Access Journals (Sweden)

    David M. Bazett-Jones

    2008-03-01

    Full Text Available While it seems that whole body vibration (WBV might be an effective modality to enhance physical performance, the proper prescription of WBV for performance enhancement remains unknown. The purpose of this study was to compare the immediate effect of various WBV accelerations on counter movement jump (CMJ height, the duration of any effect, and differences between men and women. Forty-four participants (33 men, 11 women participated in no less than four CMJ familiarization sessions and completed all vibration sessions. Participants performed a pre-test (three maximal CMJs, followed randomly by one of five WBV accelerations; 1g (no-WBV control, 2.16g, 2.80g, 4.87g, and 5.83g. Participants performed three maximal CMJs immediately, five, and 10 minutes following each 45 sec WBV session. The mean of the three performances was used and calculated as a percentage of the pre-vibration mean value. A Repeated Measures Analysis of Variance (ANOVA; acceleration x time x gender model was used to analyze the data. The two-way interactions of acceleration-gender (p = 0.033 and time-gender (p = 0.050 were significant. Women performed significantly better following the 2.80g (p = 0.0064 and 5.83g (p = 0. 0125 WBV sessions compared to the 1g (control session. Men, however, did not experience performance enhancing effects following any of the vibration sessions. While significant differences did not occur between time in either gender, the effects of the 45 sec WBV session in women were transient, lasting approximately five minutes. During the prescription of WBV, gender should be considered given that the results of this study seem to indicate that men and women respond differently to WBV. The results of this study suggest that WBV might be a useful modality as applied during the pre-competition warm-up

  9. System Performance and Testing

    NARCIS (Netherlands)

    Frei, U.; Oversloot, H.

    2004-01-01

    This chapter compares and contrasts the system performance of two widely used solar thermal systems using testing and simulation programs. Solar thermal systems are used in many countries for heating domestically used water. In addition to the simple thermosiphon systems, better designed pumped

  10. The influence of longitudinal vibrations on the heat transfer performance of inclined heat pipes

    National Research Council Canada - National Science Library

    Chen, Rong-Horng; Kuo, LW; Lai, Chi-Ming

    2015-01-01

    This study focused on investigating the influence of longitudinal vibrations, the condensation section temperature, and the inclination angles on the heat transfer performance of grooved cylindrical...

  11. Performance Monitoring of Vibration in Belt Conveyor System

    Directory of Open Access Journals (Sweden)

    S.Ojha

    2014-07-01

    Full Text Available We are always using some kind of machines in our daily life starting from fan, refrigerator and washing machines at home. In case of industries of industrial machinery items condition monitoring is important to know onset impending defects. There are so many types of indicating phenomenon such as vibration, heat, debris in oil, noise and sounds which emanate from these in efficiently running machines. This paper presents the vibration related fault identification and maintenance of belt conveyor systems (BCS. After analyzing the spectrum and vibration readings, it was observed that a combination of parallel and angular misalignment between motor & gear box was present causing high axial and radial vibration. The defect was rectified by mechanical maintenance activities and latter the vibration was found reduced within limit. Also the vibration readings were taken after rectification. The above results are presented in this paper.

  12. EFFECTS OF WHOLE-BODY VIBRATION TRAINING ON SPRINT RUNNING KINEMATICS AND EXPLOSIVE STRENGTH PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Giorgos Paradisis

    2007-03-01

    Full Text Available The aim of this study was to investigate the effect of 6 wk of whole body vibration (WBV training on sprint running kinematics and explosive strength performance. Twenty-four volunteers (12 women and 12 men participated in the study and were randomised (n = 12 into the experimental and control groups. The WBV group performed a 6-wk program (16-30 min·d-1, 3 times a week on a vibration platform. The amplitude of the vibration platform was 2.5 mm and the acceleration was 2.28 g. The control group did not participate in any training. Tests were performed Pre and post the training period. Sprint running performance was measured during a 60 m sprint where running time, running speed, step length and step rate were calculated. Explosive strength performance was measured during a counter movement jump (CMJ test, where jump height and total number of jumps performed in a period of 30 s (30CVJT. Performance in 10 m, 20 m, 40 m, 50 m and 60 m improved significantly after 6 wk of WBV training with an overall improvement of 2.7%. The step length and running speed improved by 5.1% and 3.6%, and the step rate decreased by 3.4%. The countermovement jump height increased by 3.3%, and the explosive strength endurance improved overall by 7.8%. The WBV training period of 6 wk produced significant changes in sprint running kinematics and explosive strength performance

  13. 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

    2014-01-01

    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.

  14. The influence of longitudinal vibrations on the heat transfer performance of inclined heat pipes

    Directory of Open Access Journals (Sweden)

    Rong-Horng Chen

    2015-02-01

    Full Text Available This study focused on investigating the influence of longitudinal vibrations, the condensation section temperature, and the inclination angles on the heat transfer performance of grooved cylindrical copper heat pipes with lengths of 600 and 150 mm and an outer diameter of 8 mm. The inclination angles of the tested heat pipes were 0°, ±45°, and ±90°. Longitudinal vibrations with frequencies of 3, 4, 5, 6, and 9 Hz and amplitudes of 2.8, 5, 10, 15, 20, and 25 mm, which resulted in accelerations between 0.1 and 1.01 g, were experimentally tested. The condensation section temperatures were set at 20°C, 30°C, and 40°C. A heating jacket and a cooling sleeve were installed at the evaporation and condensation sections of the test cell to simulate a constant heat flux and a constant temperature boundary, respectively. The results showed that with the heat pipe placed with the condensation section on top and the evaporation section on bottom, a fairly low and constant thermal resistance (approximately 0.25 K/W for the 600-mm heat pipe and 0.75–1.2 K/W for the 150-mm heat pipe was obtained, both with and without heat pipe vibration and regardless of the condensation section temperature.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

    field monitoring. Vibration prediction diminishes the importance of trial-and-error procedures such as drill-off tests, which are valid only for short sections. It also solves an existing lapse in Mechanical Specific Energy (MSE) real-time drilling control programs applying the theory of Teale, which states that a drilling system is perfectly efficient when it spends the exact energy to overcome the in situ rock strength. Using the proprietary software tool this paper will examine the resonant vibration modes that may be initiated while drilling with different BHA's and drill string designs, showing that the combination of a proper BHA design along with the correct selection of input parameters results in an overall improvement to drilling efficiency. Also, being the BHA predictively analyzed, it will be reduced the potential for vibration or stress fatigue in the drill string components, leading to a safer operation. In the recent years there has been an increased focus on vibration detection, analysis, and mitigation techniques, where new technologies, like the Drilling Dynamics Data Recorders (DDDR), may provide the capability to capture high frequency dynamics data at multiple points along the drilling system. These tools allow the achievement of drilling performance improvements not possible before, opening a whole new array of opportunities for optimization and for verification of predictions calculated by the drill string dynamics modeling software tool. The results of this study will identify how the dynamics from the drilling system, interacting with formation, directly relate to inefficiencies and to the possible solutions to mitigate drilling vibrations in order to improve drilling performance. Software vibration prediction and downhole measurements can be used for non-drilling operations like drilling out casing or reaming, where extremely high vibration levels - devastating to the cutting structure of the bit before it has even touched bottom - have

  16. The Influence of Acceleration on the Efficiency of Sand Compaction Tests Conducted on a Vibrating Table

    Science.gov (United States)

    Szajna, Waldemar St.

    2017-03-01

    The paper presents a standard vibrating table for fresh concrete testing adopted for determination of maximum dry density (ρdmax) of sand. Vibration is an efficient method for coarse soil compaction therefore vibrating tables are useful for ρdmax determination. Acceleration that the soil is subject to is one of the basic parameters of efficient compaction. A vibrating table with inertial excitation was supplemented by a frequency converter and subjected to dynamic tests. The results of measurements of dynamic parameters are included. The paper presents problems connected with this method and describes the relationship between efficiency of compaction and accelerations which the soil is subjected to.

  17. Force limited vibration testing: an evaluation of the computation of C2 for real load and probabilistic source

    NARCIS (Netherlands)

    Wijker, Jacob J; de Boer, Andries; Ellenbroek, Marcellinus Hermannus Maria

    2015-01-01

    To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications. Besides the random vibration specification, the total mass and the turn-over frequency of the load (test item), is a

  18. Integrated Vibration and Acceleration Testing to Reduce Payload Mass, Cost and Mission Risk Project

    Data.gov (United States)

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

  19. Solar Ultraviolet Magnetograph Investigation (SUMI) Component Responses to Payload Vibration Testing

    Science.gov (United States)

    Hunt, Ronald A.

    2011-01-01

    Vibration testing of SUMI was performed at both the experiment and payload levels. No accelerometers were installed inside the experiment during testing, but it is certain that component responses were very high. The environments experienced by optical and electronic components in these tests is an area of ongoing concern. The analysis supporting this presentation included a detailed finite element model of the SUMI experiment section, the dynamic response of which, correlated well with accelerometer measurements from the testing of the experimental section at Marshall Space Flight Center. The relatively short timeframe available to complete the task and the limited design information available was a limitation on the level of detail possible for the non-experiment portion of the model. However, since the locations of interest are buried in the experimental section of the model, the calculated responses should be enlightening both for the development of test criteria and for guidance in design.

  20. Estimate of the effect of micro-vibration on the performance of the Algerian satellite (Alsat-1B) imager

    Science.gov (United States)

    Serief, Chahira

    2017-11-01

    Alsat-1B, launched into a 670 km sun-synchronous orbit on board the PSLV launch vehicle from the Sriharikota launch site in India on 26 September 2016, is a medium resolution Earth Observation satellite with a mass of 100 kg. Alsat-1B will be used for agricultural and resource monitoring, disaster management, land use mapping and urban planning. It is based on the SSTL-100 platform, and flies a 24 m multispectral imager and a 12 m panchromatic imager delivering images with a swath width of 140 km. One of the main factors affecting the performance of satellite-borne optical imaging systems is micro-vibration. Micro-vibration is a low level mechanical disturbance inevitably generated from moving parts on a satellite and exceptionally difficult to be controlled by the attitude and orbital control system (AOCS) of a spacecraft. Micro-vibration usually causes problems for optical imaging systems onboard Earth Observation satellites. The major effect of micro-vibration is the excitation of the support structures for the optical elements during imaging operations which can result in severe degradation of image quality by smearing and distortion. Quantitative characterization of image degradation caused by micro-vibration is thus quite useful and important as part of system level analysis which can help preventing micro-vibration influence by proper design and restoring the degraded image. The aim of this work is to provide quantitative estimates of the effect of micro-vibration on the performance of Alsat-1B imager, which may be experienced operationally, in terms of the modulation transfer function (MTF) and based on ground micro-vibration tests results.

  1. A new compound control method for sine-on-random mixed vibration test

    Science.gov (United States)

    Zhang, Buyun; Wang, Ruochen; Zeng, Falin

    2017-09-01

    Vibration environmental test (VET) is one of the important and effective methods to provide supports for the strength design, reliability and durability test of mechanical products. A new separation control strategy was proposed to apply in multiple-input multiple-output (MIMO) sine on random (SOR) mixed mode vibration test, which is the advanced and intensive test type of VET. As the key problem of the strategy, correlation integral method was applied to separate the mixed signals which included random and sinusoidal components. The feedback control formula of MIMO linear random vibration system was systematically deduced in frequency domain, and Jacobi control algorithm was proposed in view of the elements, such as self-spectrum, coherence, and phase of power spectral density (PSD) matrix. Based on the excessive correction of excitation in sine vibration test, compression factor was introduced to reduce the excitation correction, avoiding the destruction to vibration table or other devices. The two methods were synthesized to be applied in MIMO SOR vibration test system. In the final, verification test system with the vibration of a cantilever beam as the control object was established to verify the reliability and effectiveness of the methods proposed in the paper. The test results show that the exceeding values can be controlled in the tolerance range of references accurately, and the method can supply theory and application supports for mechanical engineering.

  2. Effect Of Vibration On Occupant Driving Performances Measured By Simulated Driving

    Directory of Open Access Journals (Sweden)

    Amzar Azizan

    2015-08-01

    Full Text Available Although the performance of vehicle driver has been well investigated in many types of environments however drowsy driving caused by vibration has received far less attention. Experiment procedures comprised of two 10-minutes simulated driving sessions in no-vibration condition and with-vibration condition. In with-vibration condition volunteers were exposed to a Gaussian random vibration with 1-15 Hz frequency bandwidth at 0.2 ms-2 r.m.s. for 30-minutes. A deviation in lane position and vehicle speed were recorded and analyzed. Volunteers have also rated their subjective drowsiness by giving score using Karolinska Sleepiness Scale KSS every 5-minutes interval. Strong evidence of driving impairment following 30-minutes exposure to vibration were found significant in all volunteers p 0.05.

  3. The Health Monitoring Method of Concrete Dams Based on Ambient Vibration Testing and Kernel Principle Analysis

    Directory of Open Access Journals (Sweden)

    Lin Cheng

    2015-01-01

    Full Text Available The ambient vibration testing (AVT measurement of concrete dams on full-scale can show the practical dynamic properties of structure in the operation state. For most current researches, the AVT data is generally analyzed to identify the structural vibration characteristics, that is, modal parameters. The identified modal parameters, which can provide the global damage information or the damage location information of structure, can be used as the basis of structure health monitoring. Therefore, in this paper, the health monitoring method of concrete dams based on the AVT is studied. The kernel principle analysis (KPCA based method is adopted to eliminate the effect of environmental variables and monitor the health of dam under varying environments. By taking full advantage of the AVT data obtained from vibration observation system of dam, the identification capabilities and the warning capabilities of structural damage can be improved. With the simulated AVT data of the numerical model of a concrete gravity dam and the measured AVT data of a practical engineering, the performance of the dam health monitoring method proposed in this paper is verified.

  4. Force limited random vibration testing: the computation of the semi-empirical constant C2 for a real test article and unknown supporting structure

    NARCIS (Netherlands)

    Wijker, Jacob J; Ellenbroek, Marcellinus Hermannus Maria; de Boer, Andries

    2015-01-01

    To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications. Besides the random vibration specification, the total mass and the turn-over frequency of the test article (load),

  5. The Shock and Vibration Bulletin. Part 4. Vibration Testing, Instrumentation, Loads and Environments, Tracked Vehicles

    Science.gov (United States)

    1978-09-01

    distribution. . % logic. Clock speeds were kept very low, extensive buf- fering and shielding were used, and capacitive filters were This idea was...As Lorisciousness of the • . o a load from a shorted to open circuit, and capacitive to concept grows. it is expected that the control systems...transducer, and an angular velocity vibrometer . for collecting a broad base of aircraft angular Their applications will be discussed in light vibration

  6. Topographic analysis of the skull vibration-induced nystagmus test with piezoelectric accelerometers and force sensors.

    Science.gov (United States)

    Dumas, Georges; Lion, Alexis; Perrin, Philippe; Ouedraogo, Evariste; Schmerber, Sébastien

    2016-03-23

    Vibration-induced nystagmus is elicited by skull or posterior cervical muscle stimulations in patients with vestibular diseases. Skull vibrations delivered by the skull vibration-induced nystagmus test are known to stimulate the inner ear structures directly. This study aimed to measure the vibration transfer at different cranium locations and posterior cervical regions to contribute toward stimulus topographic optimization (experiment 1) and to determine the force applied on the skull with a hand-held vibrator to study the test reproducibility and provide recommendations for good clinical practices (experiment 2). In experiment 1, a 100 Hz hand-held vibrator was applied on the skull (vertex, mastoids) and posterior cervical muscles in 11 healthy participants. Vibration transfer was measured by piezoelectric sensors. In experiment 2, the vibrator was applied 30 times by two experimenters with dominant and nondominant hands on a mannequin equipped to measure the force. Experiment 1 showed that after unilateral mastoid vibratory stimulation, the signal transfer was higher when recorded on the contralateral mastoid than on the vertex or posterior cervical muscles (Pvibration transfer was measured on vertex and posterior cervical muscles. Experiment 2 showed that the force applied to the mannequin varied according to the experimenters and the handedness, higher forces being observed with the most experienced experimenter and with the dominant hand (10.3 ± 1.0 and 7.8 ± 2.9 N, respectively). The variation ranged from 9.8 to 29.4% within the same experimenter. Bone transcranial vibration transfer is more efficient from one mastoid to the other mastoid than other anatomical sites. The mastoid is therefore the optimal site for skull vibration-induced nystagmus test in patients with unilateral vestibular lesions and enables a stronger stimulation of the healthy side. In clinical practice, the vibrator should be placed on the mastoid and should be held by the clinician

  7. Evaluation of Breaking Performance in Vibration-Assisted Electrostatic Surface Induction Actuator

    DEFF Research Database (Denmark)

    Nemoto, Takeru; Zsurzsan, Tiberiu-Gabriel; Yamamoto, Akio

    2015-01-01

    force can be changed by turning on and off the vibrator. The friction change can be utilized for high-performance slider motion control; for example, friction can be increased by switching off the vibrator when the slider needs to stop. In this paper, we evaluated how fast the slider can stop in several...

  8. AVM branch vibration test equipment; Moyens d`essais vibratoires au sein du departement AMV

    Energy Technology Data Exchange (ETDEWEB)

    Anne, J.P.

    1995-12-31

    An inventory of the test equipment of the AVM Branch ``Acoustic and Vibratory Mechanics Analysis Methods`` group has been undertaken. The purpose of this inventory is to enable better acquaintance with the technical characteristics of the equipment, providing an accurate definition of their functionalities, ad to inform potential users of the possibilities and equipment available in this field. The report first summarizes the various experimental surveys conduced. Then, using the AVM equipment database to draw up an exhaustive list of available equipment, it provides a full-scope picture of the vibration measurement systems (sensors, conditioners and exciters) and data processing resources commonly used on industrial sites and in laboratories. A definition is also given of a mobile test unit, called `shelter`, and a test bench used for the testing and performance rating of the experimental analysis methods developed by the group. The report concludes with a description of two fixed installations: - the calibration bench ensuring the requisite quality level for the vibration measurement systems ; - the training bench, whereby know-how acquired in the field in the field of measurement and experimental analysis processes is made available to others. (author). 27 refs., 15 figs., 2 appends.

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

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.J.; Hofmayer, C.H. [Brookhaven National Lab., Upton, NY (United States); Costello, J.F. [Nuclear Regulatory Commission, Washington, DC (United States)

    1992-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.J.; Hofmayer, C.H. (Brookhaven National Lab., Upton, NY (United States)); Costello, J.F. (Nuclear Regulatory Commission, Washington, DC (United States))

    1992-01-01

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

  11. A General Purpose Digital System for Field Vibration Testing

    DEFF Research Database (Denmark)

    Brincker, Rune; Larsen, Jesper Abildgaard; Ventura, Carlos

    2007-01-01

    This paper describes the development and concept implementation of a highly sensitive digital recording system for seismic applications and vibration measurements on large Civil Engineering structures. The system is based on highly sensitive motion transducers that have been used by seismologists...

  12. Explosive Cratering Performance Tests

    Science.gov (United States)

    1981-07-02

    brush . This omibination of characteristics will enhance test result repeatability. 3.1.2 ’Test Area Selection Parameters. In addition to minimum...slope and absence of brush arr] timber, an optimum test area contains hciw9eneous soil types with virtually identical depth, to allow for constant charge...0 feet, 1 foot, 2 feet, 3 teet , . . . 40 feet. When tapes are fastened to radius stakes at the increment cooresponding to the stake’s distance from

  13. Vibration Durability Testing of Nickel Manganese Cobalt Oxide (NMC Lithium-Ion 18,650 Battery Cells

    Directory of Open Access Journals (Sweden)

    James Michael Hooper

    2016-01-01

    Full Text Available Electric vehicle (EV manufacturers are employing cylindrical format cells in the construction of the vehicles’ battery systems. There is evidence to suggest that both the academic and industrial communities have evaluated cell degradation due to vibration and other forms of mechanical loading. The primary motivation is often the need to satisfy the minimum requirements for safety certification. However, there is limited research that quantifies the durability of the battery and in particular, how the cells will be affected by vibration that is representative of a typical automotive service life (e.g., 100,000 miles. This paper presents a study to determine the durability of commercially available 18,650 cells and quantifies both the electrical and mechanical vibration-induced degradation through measuring changes in cell capacity, impedance and natural frequency. The impact of the cell state of charge (SOC and in-pack orientation is also evaluated. Experimental results are presented which clearly show that the performance of 18,650 cells can be affected by vibration profiles which are representative of a typical vehicle life. Consequently, it is recommended that EV manufacturers undertake vibration testing, as part of their technology selection and development activities to enhance the quality of EVs and to minimize the risk of in-service warranty claims.

  14. Effect of Frequency and Vibration Time on Shaker Performance for Mechanized Harvesting of Orange (Thomson cultivar

    Directory of Open Access Journals (Sweden)

    H Ghorbanpour

    2012-09-01

    Full Text Available Manual citrus harvesting is commonly performing hard, expensive and time consuming. In this study, a factorial experiment with a completely randomized design in three replications was performed to find out the effect of frequency (three levels of 5, 7.5 and 10 Hz, vibration time (three levels of 10, 15 and 20 seconds on harvesting capacity and losses of Thomson cultivar of orange. The results indicated that the effect of frequency and vibration time was significant (P≤0.01 on the harvesting capacity and losses, but their interaction effects weren’t significant. The harvesting capacity significantly increased by increasing frequency, and the highest harvesting capacity was 62.8 % at 10 Hz frequency. Although the harvesting capacity increased by increasing the vibration time, but there was no significant difference in vibration times between 15 and 20 seconds at 10 Hz frequency. Also the fruit loss was increased by increasing the vibration time. Due to these reasons, frequency of 10 Hz and vibration time of 15 seconds were selected as the most suitable condition for mechanized harvesting of this cultivar of orange. Finally a linear mathematical model was developed based on the frequency and vibration time for the harvesting capacity and fruit loss of Thomson cultivar of orange.

  15. Ambient Vibration Tests of an Arch Dam with Different Reservoir Water Levels: Experimental Results and Comparison with Finite Element Modelling

    Directory of Open Access Journals (Sweden)

    Sergio Vincenzo Calcina

    2014-01-01

    Full Text Available This paper deals with the ambient vibration tests performed in an arch dam in two different working conditions in order to assess the effect produced by two different reservoir water levels on the structural vibration properties. The study consists of an experimental part and a numerical part. The experimental tests were carried out in two different periods of the year, at the beginning of autumn (October 2012 and at the end of winter (March 2013, respectively. The measurements were performed using a fast technique based on asynchronous records of microtremor time-series. In-contact single-station measurements were done by means of one single high resolution triaxial tromometer and two low-frequency seismometers, placed in different points of the structure. The Standard Spectral Ratio method has been used to evaluate the natural frequencies of vibration of the structure. A 3D finite element model of the arch dam-reservoir-foundation system has been developed to verify analytically determined vibration properties, such as natural frequencies and mode shapes, and their changes linked to water level with the experimental results.

  16. Effects Of Whole Body Vibration On Vertical Jump Performance Following Exercise Induced Muscle Damage

    Directory of Open Access Journals (Sweden)

    Nicole C. Dabbs

    2014-01-01

    Full Text Available Enhancing vertical jump performance is critical for many sports. Following high intensity training, individuals often experience exercise induced muscle damage (EIMD. Many recovery modalities have been tested with conflicting results. The purpose of this investigation was to determine the effect of whole-body vibration (WBV on vertical jump performance following EIMD. 27 females volunteered for 7 sessions and were randomly assigned to a treatment or control group and administered each testing day. Vertical jump performance was assessed via vertical jump height (VJH, peak power output (PPO, rate of force development (RFD, relative ground reaction force (GRFz, and peak activation ratio of the vastus medialis (VM via electromyography (EMG before and after 3 days of EIMD via split squats. Two testing sets were collected each day, consisting of pre measures followed by WBV or control, and then post second measures. A 2x8 (group x time mixed factor analysis of variance (ANOVA was conducted for each variable. No significant interactions or group differences were found in any variable. Significant main effects for time were found in any variable, indicating performance declined following muscle damage. These results indicate that WBV does not aid in muscle recovery or vertical jump performance following EIMD.

  17. Nondestructive determination of fatigue crack damage in composites using vibration tests.

    Science.gov (United States)

    Dibenedetto, A. T.; Gauchel, J. V.; Thomas, R. L.; Barlow, J. W.

    1972-01-01

    The vibration response of glass reinforced epoxy and polyester laminates was investigated. The complex modulus and the damping capacity were measured as fatigue crack damage accumulated. Changes in the Young's modulus as well as the damping capacity correlated with the amount of crack damage. The damping was especially sensitive to debonding of the reinforcement from the resin matrix. Measurement of these vibration response changes shows promise as a means to nondestructively test the structural integrity of filament-reinforced composite structural members.

  18. Vibration Mitigation without Dissipative Devices: First Large-Scale Testing of a State Switched Inducer

    Directory of Open Access Journals (Sweden)

    Daniel Tirelli

    2014-01-01

    Full Text Available A new passive device for mitigating cable vibrations is proposed and its efficiency is assessed on 45-meter long taut cables through a series of free and forced vibration tests. It consists of a unilateral spring attached perpendicularly to the cable near the anchorage. Because of its ability to change the cable dynamic behaviour through intermittent activation, the device has been called state switched inducer (SSI. The cable behaviour is shown to be deeply modified by the SSI: the forced vibration response is anharmonicc and substantially reduced in amplitude whereas the free vibration decay is largely sped up through a beating phenomenon. The vibration mitigation effect is mainly due to the activation and coupling of various vibration modes, as evidenced in the response spectra of the equipped cable. This first large-scale experimental campaign shows that the SSI outperforms classical passive devices, thus paving the way to a new kind of low-cost vibration mitigation systems which do not rely on dissipation.

  19. Performance of a table vibration type coffee grading machine

    Directory of Open Access Journals (Sweden)

    Sukrisno Widyotomo

    2005-05-01

    Full Text Available One of important coffee beans quality is the size uniformity. To confirm with the standart requirement, coffee beans have to be graded before being traded. Until now, grading process is still carried out fully manual, so that the grading cost is very expensive about 40% of total processing cost. Meanwhile, shortage of skill workers is as a limiting factor of the process. Therefore, machine for grading coffee beans is good alternative for grading cost. Indonesian Coffee and Cocoa Research Institute has designed a table vibration type coffee grading machine for grouping of coffee beans in order to consistent quality and reduce grading cost. The machine has dimension of 272 cm length, 126 cm height, and 144 cm width. The machine has three primary components, i.e. grader table, combustion engine, and beam. The machine has three kinds of grader table that each grader table has different holes size, i.e. 7 mm x 7 mm for top grader table, 5 mm x 5 mm for axle grader table, and 4 mm x 4 mm for bottom grader table. Each grader table has dimension of 206 cm length, 105.5 cm height, and 14 cm width. The grading mechanism is by vibration grader table with the power source 5.5 HP combustion engine. The results shown that the outlet are in farms of three grades of coffee beans with connected to each compartement. Assessment of the grading machine reveals that the optimum capacity of 1,406 kg/hour reached when the speed 2,600 rpm and the angle 10O. Economic analysis showed that operational cost for grading one kilogram Robusta coffee beans with moisture content 13—14% wet basis is Rp 7.17.Key words : grading, coffee, quality, vibration table.

  20. Vibration Durability Testing of Nickel Cobalt Aluminum Oxide (NCA) Lithium-Ion 18650 Battery Cells

    OpenAIRE

    Hooper, James Michael; Marco, James; Chouchelamane, Gael Henri; Lyness, Christopher; Taylor, James

    2016-01-01

    This paper outlines a study undertaken to determine if the electrical performance of Nickel Cobalt Aluminum Oxide (NCA) 3.1 Ah 18650 battery cells can be degraded by road induced vibration typical of an electric vehicle (EV) application. This study investigates if a particular cell orientation within the battery assembly can result in different levels of cell degradation. The 18650 cells were evaluated in accordance with Society of Automotive Engineers (SAE) J2380 standard. This vibration tes...

  1. Developing Uncertainty Models for Robust Flutter Analysis Using Ground Vibration Test Data

    Science.gov (United States)

    Potter, Starr; Lind, Rick; Kehoe, Michael W. (Technical Monitor)

    2001-01-01

    A ground vibration test can be used to obtain information about structural dynamics that is important for flutter analysis. Traditionally, this information#such as natural frequencies of modes#is used to update analytical models used to predict flutter speeds. The ground vibration test can also be used to obtain uncertainty models, such as natural frequencies and their associated variations, that can update analytical models for the purpose of predicting robust flutter speeds. Analyzing test data using the -norm, rather than the traditional 2-norm, is shown to lead to a minimum-size uncertainty description and, consequently, a least-conservative robust flutter speed. This approach is demonstrated using ground vibration test data for the Aerostructures Test Wing. Different norms are used to formulate uncertainty models and their associated robust flutter speeds to evaluate which norm is least conservative.

  2. Design, analysis and testing of a new piezoelectric tool actuator for elliptical vibration turning

    Science.gov (United States)

    Lin, Jieqiong; Han, Jinguo; Lu, Mingming; Yu, Baojun; Gu, Yan

    2017-08-01

    A new piezoelectric tool actuator (PETA) for elliptical vibration turning has been developed based on a hybrid flexure hinge connection. Two double parallel four-bar linkage mechanisms and two right circular flexure hinges were chosen to guide the motion. The two input displacement directional stiffness were modeled according to the principle of virtual work modeling method and the kinematic analysis was conducted theoretically. Finite element analysis was used to carry out static and dynamic analyses. To evaluate the performance of the developed PETA, off-line experimental tests were carried out to investigate the step responses, motion strokes, resolutions, parasitic motions, and natural frequencies of the PETA along the two input directions. The relationship between input displacement and output displacement, as well as the tool tip’s elliptical trajectory in different phase shifts was analyzed. By using the developed PETA mechanism, micro-dimple patterns were generated as the preliminary application to demonstrate the feasibility and efficiency of PETA for elliptical vibration turning.

  3. Objectives and Progress on Ground Vibration Testing for the Ares Projects

    Science.gov (United States)

    Tuma, Margaret L.; Chenevert, Donald J.

    2010-01-01

    Integrated vehicle ground vibration testing (IVGVT) will be a vital component for ensuring the safety of NASA s next generation of exploration vehicles to send human beings to the Moon and beyond. A ground vibration test (GVT) measures the fundamental dynamic characteristics of launch vehicles during various phases of flight. The Ares Flight & Integrated Test Office (FITO) will be conducting the IVGVT for the Ares I crew launch vehicle at Marshall Space Flight Center (MSFC) from 2012 to 2014 using Test Stand (TS) 4550. MSFC conducted similar GVT for the Saturn V and Space Shuttle vehicles. FITO will perform the IVGVT on the Ares I crew launch vehicle, which will lift the Orion crew exploration vehicle to low Earth orbit, and the Ares V cargo launch vehicle, which can launch the lunar lander into orbit and send the combined Orion/lander vehicles toward the Moon. Ares V consists of a six-engine core stage with two solid rocket boosters and an Earth departure stage (EDS). The same engine will power the EDS and the Ares I second stage. The current plan is to test six configurations in three unique test positions inside TS 4550. Four Ares I second stage test configurations will be tested in Position 3, consisting of the Upper Stage and Orion crew module in four nominal conditions: J-2X engine ignition, post Launch Abort System (LAS) jettison, critical slosh mass, and J-2X burn-out. Position 2 consists of the entire launch stack at first stage burn-out (using empty first stage segments). Position 1 represents the entire launch stack at lift-off (using inert first stage segments). Because of long disuse, TS 4550 is being repaired and modified for reactivation to conduct the Ares I IVGVT. The Shuttle-era platforms have been removed and are being replaced with mast climbers that provide ready access to the test articles and can be moved easily to support different positions within the test stand. Two new cranes will help move test articles at the test stand and at the

  4. Ground vibration test results for Drones for Aerodynamic and Structural Testing (DAST)/Aeroelastic Research Wing (ARW-1R) aircraft

    Science.gov (United States)

    Cox, T. H.; Gilyard, G. B.

    1986-01-01

    The drones for aerodynamic and structural testing (DAST) project was designed to control flutter actively at high subsonic speeds. Accurate knowledge of the structural model was critical for the successful design of the control system. A ground vibration test was conducted on the DAST vehicle to determine the structural model characteristics. This report presents and discusses the vibration and test equipment, the test setup and procedures, and the antisymmetric and symmetric mode shape results. The modal characteristics were subsequently used to update the structural model employed in the control law design process.

  5. Drop Performance Test of CRDMs for JRTR

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Myoung-Hwan; Cho, Yeong-Garp; Chung, Jong-Ha [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jung-Hyun [POSCO Plandtec Co. Ltd, Ulsan (Korea, Republic of); Lee, Kwan-Hee [RIST, Pohang (Korea, Republic of)

    2015-10-15

    The drop test results of CRDMs with AC-type electromagnet show that the initial delay times are not satisfied with the requirement, 0.15 seconds. After the replacement of the electromagnet from AC-type to DCtype, the drop times of CARs and accelerations due to the impact of moving parts are satisfied with all requirements. As a result, it is found that four CRDMs to be installed at site have a good drop performance, and meet all performance requirements. A control rod drive mechanism (CRDM) is a device to control the position of a control absorber rod (CAR) in the core by using a stepping motor which is commanded by the reactor regulating system (RRS) to control the reactivity during the normal operation of the reactor. The top-mounted CRDM driven by the stepping motor for Jordan Research and Training Reactor (JRTR) has been developed in KAERI. The CRDM for JRTR has been optimized by the design improvement based on that of the HANARO. It is necessary to verify the performances such as the stepping, drop, endurance, vibration, seismic and structural integrity for active components. Especially, the CAR drop curves are important data for the safety analysis. This paper describes the test results to demonstrate the drop performances of a prototype and 4 CRDMs to be installed at site. The tests are carried out at a test rig simulating the actual reactor's conditions.

  6. Shock and vibration tests of uranium mononitride fuel pellets for a space power nuclear reactor

    Science.gov (United States)

    Adams, D. W.

    1972-01-01

    Shock and vibration tests were conducted on cylindrically shaped, depleted, uranium mononitride (UN) fuel pellets. The structural capabilities of the pellets were determined under exposure to shock and vibration loading which a nuclear reactor may encounter during launching into space. Various combinations of diametral and axial clearances between the pellets and their enclosing structures were tested. The results of these tests indicate that for present fabrication of UN pellets, a diametral clearance of 0.254 millimeter and an axial clearance of 0.025 millimeter are tolerable when subjected to launch-induced loads.

  7. The relationship between clinical and standardized tests for hand-arm vibration syndrome.

    Science.gov (United States)

    Poole, C J M; Mason, H; Harding, A-H

    2016-06-01

    Standardized laboratory tests are undertaken to assist the diagnosis and staging of hand-arm vibration syndrome (HAVS), but the strength of the relationship between the tests and clinical stages of HAVS is unknown. To assess the relationship between the results of thermal aesthesiometry (TA), vibrotactile (VT) thresholds and cold provocation (CP) tests with the modified Stockholm scales for HAVS and to determine whether the relationship is affected by finger skin temperature. Consecutive records of workers referred to a Tier 5 HAVS assessment centre from 2006 to 2015 were identified. The diagnosis and staging of cases was undertaken from the clinical information contained in the records. Cases with alternative or mixed diagnoses were excluded and staging performed according to the modified Stockholm scale without knowledge of the results of the standardized laboratory tests. A total of 279 cases of HAVS were analysed. Although there was a significant trend for sensorineural (SN) and vascular scores to increase with clinical stage (P 30°C. CP scores distributed bimodally and correlated poorly with clinical staging (r = 0.2). Standardized SN tests distinguish between the lower Stockholm stages, but not above 2SN early. This has implications for health surveillance and UK policy. © Crown copyright 2016.

  8. Effectiveness of Different Rest Intervals Following Whole-Body Vibration on Vertical Jump Performance between College Athletes and Recreationally Trained Females

    Directory of Open Access Journals (Sweden)

    Nicole C. Dabbs

    2015-09-01

    Full Text Available The purpose of this study was to evaluate the effect of different rest intervals following whole-body vibration on counter-movement vertical jump performance. Sixteen females, eight recreationally trained and eight varsity athletes volunteered to participate in four testing visits separated by 24 h. Visit one acted as a familiarization visit where subjects were introduced to the counter-movement vertical jump and whole-body vibration protocols. Visits 2–4 contained 2 randomized conditions. Whole-body vibration was administered in four bouts of 30 s with 30 s rest between bouts. During whole-body vibration subjects performed a quarter squat every 5 s, simulating a counter-movement vertical jump. Whole-body vibration was followed by three counter-movement vertical jumps with five different rest intervals between the vibration exposure and jumping. For a control condition, subjects performed squats with no whole-body vibration. There was a significant (p < 0.05 main effect for time for vertical jump height, peak power output, and relative ground reaction forces, where a majority of individuals max jump from all whole-body vibration conditions was greater than the control condition. There were significant (p < 0.05 group differences, showing that varsity athletes had a greater vertical jump height and peak power output compared to recreationally trained females. There were no significant (p > 0.05 group differences for relative ground reaction forces. Practitioners and/or strength and conditioning coaches may utilize whole-body vibration to enhance acute counter-movement vertical jump performance after identifying individuals optimal rest time in order to maximize the potentiating effects.

  9. Designing, modelling and testing of vibration energy harvester with nonlinear stiffness

    Science.gov (United States)

    Rubes, Ondrej; Hadas, Zdenek

    2017-05-01

    This paper is focused on a design of a piezoelectric vibration energy harvester with an additional nonlinear stiffness. Common piezoelectric energy harvesters consist of a cantilever with piezoceramic layers and a tip mass for tuning up the operation frequency. This system is excited by mechanical vibrations and it provides an autonomous source of electrical energy. A linear stiffness of the cantilever has very narrow resonance frequency bandwidth which makes the piezoelectric cantilever sensitive to tuning up of the resonance frequency. It could be tuned only for one narrow vibration frequency bandwidth. The piezoelectric vibration energy harvester with nonlinear stiffness could provide the resonance frequency bandwidth wider and it allows energy harvesting from the wider bandwidth of excitation vibrations. The additional nonlinear stiffness is implemented by using a set of permanent magnets. A simulation and an experiment were performed and the results show a wider resonance bandwidth. However, it depended on direction of vibration frequency sweeping. The frequency bandwidth is more than three times wider but there is only a half resonance amplitude of oscillations. That means that the maximal harvested power is lower but the average harvested power around resonance frequency was higher which was the goal of this research.

  10. Integrated Vehicle Ground Vibration Testing in Support of NASA Launch Vehicle Loads and Controls Analysis

    Science.gov (United States)

    Tuma, Margaret L.; Davis, Susan R.; Askins, Bruce R.; Salyer, Blaine H.

    2008-01-01

    The National Aeronautics and Space Administration (NASA) Ares Projects Office (APO) is continuing to make progress toward the final design of the Ares I crew launch vehicle and Ares V cargo launch vehicle. Ares I and V will form the space launch capabilities necessary to fulfill NASA's exploration strategy of sending human beings to the Moon, Mars, and beyond. As with all new space vehicles there will be a number of tests to ensure the design can be Human Rated. One of these is the Integrated Vehicle Ground Vibration Test (IVGVT) that will be measuring responses of the Ares I as a system. All structural systems possess a basic set of physical characteristics unique to that system. These unique characteristics include items such as mass distribution, frequency and damping. When specified, they allow engineers to understand and predict how a structural system like the Ares I launch vehicle behaves under given loading conditions. These physical properties of launch vehicles may be predicted by analysis or measured through certain types of tests. Generally, these properties are predicted by analysis during the design phase of a launch vehicle and then verified through testing before the vehicle is Human Rated. The IVGVT is intended to measure by test the fundamental dynamic characteristics of Ares I during various phases of operational/flight. This testing includes excitations of the vehicle in lateral, longitudinal, and torsional directions at vehicle configurations representing different trajectory points. During the series of tests, properties such as natural frequencies, mode shapes, and transfer functions are measured directly. These data will then be used to calibrate loads and Guidance, Navigation, and Controls (GN&C) analysis models for verifying analyses of Ares I. NASA launch vehicles from Saturn to Shuttle have undergone Ground Vibration Tests (GVTs) leading to successful launch vehicles. A GVT was not performed on the unmanned Delta III. This vehicle was

  11. Ambient Vibration Testing for Story Stiffness Estimation of a Heritage Timber Building

    Directory of Open Access Journals (Sweden)

    Kyung-Won Min

    2013-01-01

    Full Text Available This paper investigates dynamic characteristics of a historic wooden structure by ambient vibration testing, presenting a novel estimation methodology of story stiffness for the purpose of vibration-based structural health monitoring. As for the ambient vibration testing, measured structural responses are analyzed by two output-only system identification methods (i.e., frequency domain decomposition and stochastic subspace identification to estimate modal parameters. The proposed methodology of story stiffness is estimation based on an eigenvalue problem derived from a vibratory rigid body model. Using the identified natural frequencies, the eigenvalue problem is efficiently solved and uniquely yields story stiffness. It is noteworthy that application of the proposed methodology is not necessarily confined to the wooden structure exampled in the paper.

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

    Science.gov (United States)

    Shibata, Nobuyuki

    2017-10-05

    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 years 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.

  13. Vibration-induced coherence enhancement of the performance of a biological quantum heat engine.

    Science.gov (United States)

    Chen, Hong-Bin; Chiu, Pin-Yi; Chen, Yueh-Nan

    2016-11-01

    Photosynthesis has been a long-standing research interest due to its fundamental importance. Recently, studies on photosynthesis processes also have inspired attention from a thermodynamical aspect when considering photosynthetic apparatuses as biological quantum heat engines. Quantum coherence is shown to play a crucial role in enhancing the performance of these quantum heat engines. Based on the experimentally reported structure, we propose a quantum heat engine model with a non-Markovian vibrational mode. We show that one can obtain a performance enhancement easily for a wide range of parameters in the presence of the vibrational mode. Our results provide insights into the photosynthetic processes and a design principle mimicking natural organisms.

  14. Vibration-induced coherence enhances the performance of a biological quantum heat engine

    CERN Document Server

    Chen, Hong-Bin; Chen, Yueh-Nan

    2016-01-01

    Photosynthesis has been the long-standing research interest due to its fundamental importance. Recently, studies on photosynthesis processes also inspire attention from thermodynamical aspect when considering photosynthetic apparatuses as biological quantum heat engines. Quantum coherence is shown to play a crucial role in enhancing the performance of these quantum heat engines. Based on the experimentally reported structure, we propose a quantum heat engine model with a non-Markovian vibrational mode. We show that one can obtain a performance enhancement easily for a wide range of parameters in the presence of the vibrational mode. Our results suggest new insights into the photosynthetic processes and a design principle mimicking natural organisms.

  15. Ensuring Safe Exploration: Ares Launch Vehicle Integrated Vehicle Ground Vibration Testing

    Science.gov (United States)

    Tuma, M. L.; Chenevert, D. J.

    2010-01-01

    Integrated vehicle ground vibration testing (IVGVT) will be a vital component for ensuring the safety of NASA's next generation of exploration vehicles to send human beings to the Moon and beyond. A ground vibration test (GVT) measures the fundamental dynamic characteristics of launch vehicles during various phases of flight. The Ares Flight & Integrated Test Office (FITO) will be leading the IVGVT for the Ares I crew launch vehicle at Marshall Space Flight Center (MSFC) from 2012 to 2014 using Test Stand (TS) 4550. MSFC conducted similar GVT for the Saturn V and Space Shuttle vehicles. FITO is responsible for performing the IVGVT on the Ares I crew launch vehicle, which will lift the Orion crew exploration vehicle to low Earth orbit, and the Ares V cargo launch vehicle, which can launch the lunar lander into orbit and send the combined Orionilander vehicles toward the Moon. Ares V consists of a six-engine core stage with two solid rocket boosters and an Earth departure stage (EDS). The same engine will power the EDS and the Ares I second stage. For the Ares IVGVT, the current plan is to test six configurations in three unique test positions inside TS 4550. Position 1 represents the entire launch stack at liftoff (using inert first stage segments). Position 2 consists of the entire launch stack at first stage burn-out (using empty first stage segments). Four Ares I second stage test configurations will be tested in Position 3, consisting of the Upper Stage and Orion crew module in four nominal conditions: J-2X engine ignition, post Launch Abort System (LAS) jettison, critical slosh mass, and J-2X burn-out. Because of long disuse, TS 4550 is being repaired and reactivated to conduct the Ares I IVGVT. The Shuttle-era platforms have been removed and are being replaced with mast climbers that provide ready access to the test articles and can be moved easily to support different positions within the test stand. The electrical power distribution system for TS 4550 was

  16. NASA-DoD Lead-Free Electronics Project: Vibration Test

    Science.gov (United States)

    Woodrow, Thomas A.

    2010-01-01

    Vibration testing was conducted by Boeing Research and Technology (Seattle) for the NASA-DoD Lead-Free Electronics Solder Project. This project is a follow-on to the Joint Council on Aging Aircraft/Joint Group on Pollution Prevention (JCAA/JG-PP) Lead-Free Solder Project which was the first group to test the reliability of lead-free solder joints against the requirements of the aerospace/miLItary community. Twenty seven test vehicles were subjected to the vibration test conditions (in two batches). The random vibration Power Spectral Density (PSD) input was increased during the test every 60 minutes in an effort to fail as many components as possible within the time allotted for the test. The solder joints on the components were electrically monitored using event detectors and any solder joint failures were recorded on a Labview-based data collection system. The number of test minutes required to fail a given component attached with SnPb solder was then compared to the number of test minutes required to fail the same component attached with lead-free solder. A complete modal analysis was conducted on one test vehicle using a laser vibrometer system which measured velocities, accelerations, and displacements at one . hundred points. The laser vibrometer data was used to determine the frequencies of the major modes of the test vehicle and the shapes of the modes. In addition, laser vibrometer data collected during the vibration test was used to calculate the strains generated by the first mode (using custom software). After completion of the testing, all of the test vehicles were visually inspected and cross sections were made. Broken component leads and other unwanted failure modes were documented.

  17. Wind-Tunnel Tests of a Bridge Model with Active Vibration Control

    DEFF Research Database (Denmark)

    Hansen, H. I.; Thoft-Christensen, Palle; Mendes, P. A.

    The application of active control systems to reduce wind vibrations in bridges is a new area of research. This paper presents the results that were obtained on a set of wind tunnel tests of a bridge model equipped with active movable flaps. Based on the monitored position and motion of the deck...

  18. Lumped Parameter Modeling for Rapid Vibration Response Prototyping and Test Correlation for Electronic Units

    Science.gov (United States)

    Van Dyke, Michael B.

    2013-01-01

    Present preliminary work using lumped parameter models to approximate dynamic response of electronic units to random vibration; Derive a general N-DOF model for application to electronic units; Illustrate parametric influence of model parameters; Implication of coupled dynamics for unit/board design; Demonstrate use of model to infer printed wiring board (PWB) dynamics from external chassis test measurement.

  19. Vibration test on KMRR reactor structure and primary cooling system piping

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-10-01

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

  20. Lessons learned from CIRFT testing on SNF vibration integrity study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Hong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jiang, Hao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bevard, Bruce Balkcom [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Rob L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Scaglione, John M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    A cyclic integrated reversible-bending fatigue tester (CIRFT) was developed to support U.S. NRC and DOE Used Fuel Disposition Campaign studies on high burn-up (HBU) spent nuclear fuel (SNF) transportation during normal conditions of transport (NCT). Two devices were developed; the first CIRFT was successfully installed and operated in the ORNL hot-cells in September 2013. Since hot cell testing commenced several HBU SNF samples from both Zr-4 and M5 clads were investigated. The second CIRFT device was developed in February 2014, and has been used to test clad/fuel surrogate rods (stainless steel with alumina pellet inserts). The second CIRFT machine has also been used for sensor development and test sensitivity analyses, as well as loading boundary condition parameter studies. The lessons learned from CIRFT testing will be presented in this paper.

  1. Coupled thermal, structural and vibrational analysis of a hypersonic engine for flight test

    Energy Technology Data Exchange (ETDEWEB)

    Sook-Ying, Ho [Defence Science and Technology Organisation, SA (Australia); Paull, A. [Queensland Univ., Dept. of Mechanical Engineering (Australia)

    2006-07-15

    This paper describes a relatively simple and quick method for implementing aerodynamic heating models into a finite element code for non-linear transient thermal-structural and thermal-structural-vibrational analyses of a Mach 10 generic HyShot scram-jet engine. The thermal-structural-vibrational response of the engine was studied for the descent trajectory from 60 to 26 km. Aerodynamic heating fluxes, as a function of spatial position and time for varying trajectory points, were implemented in the transient heat analysis. Additionally, the combined effect of varying dynamic pressure and thermal loads with altitude was considered. This aero-thermal-structural analysis capability was used to assess the temperature distribution, engine geometry distortion and yielding of the structural material due to aerodynamic heating during the descent trajectory, and for optimising the wall thickness, nose radius of leading edge, etc. of the engine intake. A structural vibration analysis was also performed following the aero-thermal-structural analysis to determine the changes in natural frequencies of the structural vibration modes that occur at the various temperatures associated with the descent trajectory. This analysis provides a unique and relatively simple design strategy for predicting and mitigating the thermal-structural-vibrational response of hypersonic engines. (authors)

  2. A Procedure for Accurately Measuring the Shaker Overturning Moment During Random Vibration Tests

    Science.gov (United States)

    Nayeri, Reza D.

    2011-01-01

    Motivation: For large system level random vibration tests, there may be some concerns about the shaker's capability for the overturning moment. It is the test conductor's responsibility to predict and monitor the overturning moment during random vibration tests. If the predicted moment is close to the shaker's capability, test conductor must measure the instantaneous moment at low levels and extrapolate to higher levels. That data will be used to decide whether it is safe to proceed to the next test level. Challenge: Kistler analog formulation for computing the real-time moment is only applicable to very limited cases in which we have 3 or 4 load cells installed at shaker interface with hardware. Approach: To overcome that limitation, a simple procedure was developed for computing the overturning moment time histories using the measured time histories of the individual load cells.

  3. Performance testing With JMeter 29

    CERN Document Server

    Erinle, Bayo

    2013-01-01

    Performance Testing With JMeter 2.9 is a standard tutorial that will help you polish your fundamentals, guide you through various advanced topics, and along the process help you learn new tools and skills.This book is for developers, quality assurance engineers, testers, and test managers new to Apache JMeter, or those who are looking to get a good grounding in how to effectively use and become proficient with it. No prior testing experience is required.

  4. Effect of whole-body vibration training on body composition, exercise performance and biochemical responses in middle-aged mice.

    Science.gov (United States)

    Lin, Ching-I; Huang, Wen-Ching; Chen, Wen-Chyuan; Kan, Nai-Wen; Wei, Li; Chiu, Yen-Shuo; Huang, Chi-Chang

    2015-09-01

    Whole-body vibration (WBV) is a well-known light-resistance exercise by automatic adaptations to rapid and repeated oscillations from a vibrating platform, which is also a simple and convenient exercise for older adults. However, the potential benefits of WBV on aging-associated changes in body composition, exercise performance, and fatigue are currently unclear. The objective of the study is to investigate the beneficial effects of WBV training on body composition, exercise performance, and physical fatigue-related and biochemical responses in middle-aged mice. In total, 24 male C57BL/6 mice aged 15 months old were randomly divided into 3 groups (n=8 per group): sedentary control (SC), relatively low-frequency WBV (5.6 Hz, 2 mm, 0.13 g) (LV), and relatively high-frequency WBV (13 Hz, 2 mm, 0.68 g) (HV). Mice in the LV and HV groups were placed inside a vibration platform and vibrated at different frequencies and fixed amplitude (2 mm) for 15 min, 5 days/week for 4 weeks. Exercise performance, core temperature and anti-fatigue function were evaluated by forelimb grip strength and levels of serum lactate, ammonia, glucose, and creatine kinase (CK) after a 15-min swimming exercise, as were changes in body composition and biochemical variables at the end of the experiment. Relative muscle and brown adipose tissue weight (%) was significantly higher for the HV than SC mice, but relative liver weight (%) was lower. On trend analysis, WBV increased grip strength, aerobic endurance and core temperature in mice. As well, serum lactate, ammonia and CK levels were dose-dependently decreased with vibration frequency after the swimming test. Fasting serum levels of albumin and total protein were increased and serum levels of alkaline phosphatase and creatinine decreased dose-dependently with vibration frequency. Moreover, WBV training improved the age-related abnormal morphology of skeletal muscle, liver and kidney tissues. Therefore, it could improve exercise performance and

  5. Fatigue Failure Results for Multi-Axial versus Uniaxial Stress Screen Vibration Testing

    Directory of Open Access Journals (Sweden)

    Wayne E. Whiteman

    2002-01-01

    Full Text Available To date, the failure potential and prediction between simultaneous multi-axial versus sequentially applied uniaxial vibration stress screen testing has been the subject of great debate. In most applications, current vibration tests are done by sequentially applying uniaxial excitation to the test specimen along three orthogonal axes. The most common standards for testing military equipment are published in MIL-STD-810F and NAVMAT P-9492. Previous research had shown that uniaxial testing may be unrealistic and inadequate. This current research effort is a continuing effort to systematically investigate the differences between fatigue damage mechanisms and the effects of uniaxial versus tri-axial testing. This includes assessing the ability of the tri-axial method in predicting the formation of damage mechanisms, specifically looking at the effects of stress or fatigue failure. Multi-axial testing achieves the synergistic effect of exciting all modes simultaneously and induces a more realistic vibration stress loading condition. As such, it better approximates real-world operating conditions. This paper provides the latest results on the differences between multi-axial and uniaxial testing of a simple notched cantilever beam.

  6. Performance of nonlinear mechanical, resonant-shunted piezoelectric, and electronic vibration absorbers for multi-degree-of-freedom structures

    Science.gov (United States)

    Agnes, Gregory Stephen

    Linear vibration absorbers are a valuable tool used to suppress vibrations due to harmonic excitation in structural systems. Limited evaluation of the performance of nonlinear vibration absorbers for nonlinear structures exists in the current literature. The state of the art is extended in this work to vibration absorbers in their three major physical implementations: the mechanical vibration absorber, the inductive-resistive shunted piezoelectric vibration absorber, and the electronic vibration absorber (also denoted a positive position feedback controller). A single, consistent, physically similar model capable of examining the response of all three devices is developed. The performance of vibration absorbers attached to single-degree-of-freedom structures is next examined for performance, robustness, and stability. Perturbation techniques and numerical analysis combine to yield insight into the tuning of nonlinear vibration absorbers for both linear and nonlinear structures. The results both clarify and validate the existing literature on mechanical vibration absorbers. Several new results, including an analytical expression for the suppression region's location and bandwidth and requirements for its robust performance, are derived. Nonlinear multiple-degree-of-freedom structures are next evaluated. The theory of Non-linear Normal Modes is extended to include consideration of modal damping, excitation, and small linear coupling, allowing estimation of vibration absorber performance. The dynamics of the N+1-degree-of-freedom system reduce to those of a two-degree-of-freedom system on a four-dimensional nonlinear modal manifold, thereby simplifying the analysis. Quantitative agreement is shown to require a higher order model which is recommended for future investigation. Finally, experimental investigation on both single and multi-degree-of-freedom systems is performed since few experiments on this topic are reported in the literature. The experimental results

  7. Design of Accelerated Reliability Test for CNC Motorized Spindle Based on Vibration Signal

    Directory of Open Access Journals (Sweden)

    Chen Chao

    2016-01-01

    Full Text Available Motorized spindle is the key functional component of CNC machining centers which is a mechatronics system with long life and high reliability. The reliability test cycle of motorized spindle is too long and infeasible. This paper proposes a new accelerated test for reliability evaluation of motorized spindle. By field reliability test, authors collect and calculate the load data including rotational speed, cutting force and torque. Load spectrum distribution law is analyzed. And authors design a test platform to apply the load spectrum. A new method to define the fuzzy acceleration factor based on the vibration signal is proposed. Then the whole test plan of accelerated reliability test is done.

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

    Science.gov (United States)

    Heffer, R.

    1998-01-01

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

  9. EFFECTS OF WHOLE BODY VIBRATION ON STRENGTH AND JUMPING PERFORMANCE IN VOLLEYBALL AND BEACH VOLLEYBALL PLAYERS

    Science.gov (United States)

    Zmijewski, P.; Jimenez-Olmedo, J.M.; Jové-Tossi, M.A.; Martínez-Carbonell, A.; Suárez-Llorca, C.; Andreu-Cabrera, E.

    2014-01-01

    The primary aim of this study was to examine the effects of 6-week strength training with whole body vibration (WBV) on leg strength and jumping performance in volleyball and beach volleyball players. Twenty-three sub-elite male volleyball (VB; n=12) and beach volleyball players (BVB; n=11) aged 21.2±3.0 years were divided into two groups and subjected to 6 weeks of strength training (three one-hour sessions per week): (I) 12 players (6 VB and 6 BVB players) underwent training with WBV (30-40 Hz, 1.7-2.5 mm, 3.0-5.7 g), and (II) 11 players (6 VB and 5 BVB players) underwent traditional strength training. Squat jump (SJ) and countermovement squat jump (CMJ) measurements by the Ergo Tester contact platform and maximum leg press test (1RM) were conducted. Three-factor (2 time x 2 WBV use x 2 discipline) analysis of variance for SJ, CMJ and 1RM revealed a significant time main effect (pvolleyball and beach volleyball players increases leg strength more and leads to greater improvement in jump performance than traditional strength training, but greater improvements can be expected in beach volleyball players than in volleyball players. PMID:25187676

  10. Whole-body vibration training effect on physical performance and obesity in mice.

    Science.gov (United States)

    Huang, Chi-Chang; Tseng, Tzu-Ling; Huang, Wen-Ching; Chung, Yi-Hsiu; Chuang, Hsiao-Li; Wu, Jyh-Horng

    2014-01-01

    The purpose of this study was to verify the beneficial effects of whole-body vibration (WBV) training on exercise performance, physical fatigue and obesity in mice with obesity induced by a high-fat diet (HFD). Male C57BL/6 mice were randomly divided into two groups: normal group (n=6), fed standard diet (control), and experimental group (n=18), fed a HFD. After 4-week induction, followed by 6-week WBV of 5 days per week, the 18 obese mice were divided into 3 groups (n=6 per group): HFD with sedentary control (HFD), HFD with WBV at relatively low-intensity (5.6 Hz, 0.13 g) (HFD+VL) or high-intensity (13 Hz, 0.68 g) (HFD+VH). A trend analysis revealed that WBV increased the grip strength in mice. WBV also dose-dependently decreased serum lactate, ammonia and CK levels and increased glucose level after the swimming test. WBV slightly decreased final body weight and dose-dependently decreased weights of epididymal, retroperitoneal and perirenal fat pads and fasting serum levels of alanine aminotransferase, CK, glucose, total cholesterol and triacylglycerol. Therefore, WBV could improve exercise performance and fatigue and prevent fat accumulation and obesity-associated biochemical alterations in obese mice. It may be an effective intervention for health promotion and prevention of HFD-induced obesity.

  11. Performance Testing of Cutting Fluids

    DEFF Research Database (Denmark)

    Belluco, Walter

    The importance of cutting fluid performance testing has increased with documentation requirements of new cutting fluid formulations based on more sustainable products, as well as cutting with minimum quantity of lubrication and dry cutting. Two sub-problems have to be solved: i) which machining...... tests feature repeatability, reproducibility and sensitivity to cutting fluids, and ii) to what extent results of one test ensure relevance to a wider set of machining situations. The present work is aimed at assessing the range of validity of the different testing methods, investigating correlation...... within the whole range of operations, materials, cutting fluids, operating conditions, etc. Cutting fluid performance was evaluated in turning, drilling, reaming and tapping, and with respect to tool life, cutting forces, chip formation and product quality (dimensional accuracy and surface integrity...

  12. The Effects of Whole Body Vibration Training and Creatine Supplementation on Lower Extremity Performance and Balance in Elderly Males

    Directory of Open Access Journals (Sweden)

    Mostafa Rahimi

    2011-04-01

    Full Text Available Objectives: The purpose of this study was to investigate the effects of whole body vibration training (WBVT and creatine (Cr supplementation on lower extremity performance and balance in elderly males. Methods & Materials: In this semi-experimental study, twenty two eligible males from the members of an elderly daycare center with more than 60 years of age were enrolled and were divided into three groups randomly, WBVT+Cr(n=7, WBVT+Pgroup (n=7, and control group (n=8. In WBVT+Cr and WBVT+P groups exercises were performed on the whole body vibration device for 10 days with 30-35 Hz intensity and 5 mm amplitude. The WBVT+Cr group consumed 20g/day Crsupplement for the first 5 days followed by 5g/days for the next 5 days of protocol. The WBVT+P group consumed dexterous. The control group neither did any exercise nor consumed any supplement during the protocol. Static balance by standing time on one leg, dynamic balance by TUG test and lower extremity performance by 30-meter walking test, sit and stand test and tandem gait test weremeasured. Paired sample t-test and one way ANOVAwere used for data analysis (α=0.05. Results: Our results showed that dynamic balance, lower body performance in 30- meter walking and tandem gait improved in experimental groups. However, ANOVA did not show any significant increase in static balance (P=0.514, dynamic balance (P=0.153, lower body performance in 30-meter walking test (P=0.339, sit and stand test (P=0.578 and tandem gait (P=0.151. Conclusion: In conclusion, it seems that WBVT plus Cr supplementation improves some of the motor fitness factors in elderly males during a short time.

  13. Sensor Placement Optimization of Vibration Test on Medium-Speed Mill

    Directory of Open Access Journals (Sweden)

    Lihua Zhu

    2015-01-01

    Full Text Available Condition assessment and decision making are important tasks of vibration test on dynamic machines, and the accuracy of dynamic response can be achieved by the sensors placed on the structure reasonably. The common methods and evaluation criteria of optimal sensor placement (OSP were summarized. In order to test the vibration characteristic of medium-speed mill in the thermal power plants, the optimal placement of 12 candidate measuring points in X, Y, and Z directions on the mill was discussed for different targeted modal shapes, respectively. The OSP of medium-speed mill was conducted using the effective independence method (EfI and QR decomposition algorithm. The results showed that the order of modal shapes had an important influence on the optimization results. The difference of these two methods on the sensor placement optimization became smaller with the decrease of the number of target modes. The final scheme of OSP was determined based on the optimal results and the actual test requirements. The field test results were basically consistent with the finite element analysis results, which indicated the sensor placement optimization for vibration test on the medium-speed mill was feasible.

  14. Sensor design for outdoor racing bicycle field testing for human vibration comfort evaluation

    Science.gov (United States)

    Vanwalleghem, Joachim; De Baere, Ives; Loccufier, Mia; Van Paepegem, Wim

    2013-09-01

    This paper is concerned with the vibrational comfort evaluation of the cyclist when cycling a rough surface. Outdoor comfort tests have so far only been done through instrumenting the bicycle with accelerometers. This work instruments a racing bicycle with custom-made contact force sensors and velocity sensors to acquire human comfort through the absorbed power method. Comfort evaluation is assessed at the hand-arm and seat interface of the cyclist with the bicycle. By means of careful finite-element analysis for designing the force gauges at the handlebar and the seat combined with precise calibration of both force and velocity sensors, all sensors have proven to work properly. Initial field tests are focused on the proper functioning of the designed sensors and their suitability for vibration comfort measurements. Tests on a cobblestone road reveal that the outcome of the absorbed power values is within the same range as those from laboratory tests found in the literature. This sensor design approach for outdoor testing with racing bicycles may give a new interpretation on evaluating the cyclist's comfort since the vibrational load is not only quantified in terms of acceleration but also in terms of force and velocity at the bicycle-cyclist contact points.

  15. Force limited random vibration testing: the computation of the semi-empirical constant $C(2) $ C 2 for a real test article and unknown supporting structure

    Science.gov (United States)

    Wijker, J. J.; Ellenbroek, M. H. M.; Boer, A. de

    2015-09-01

    To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications. Besides the random vibration specification, the total mass and the turn-over frequency of the test article (load), C^2 is a very important parameter for FLVT. A number of computational methods to estimate C^2 are described in the literature, i.e. the simple and the complex two degree of freedom system, STDFS and CTDFS, respectively. The motivation of this work is to evaluate the method for the computation of a realistic value of C^2 to perform a representative random vibration test based on force limitation, when the description of the supporting structure (source) is more or less unknown. Marchand discussed the formal description of obtaining C^2, using the maximum PSD of the acceleration and maximum PSD of the force, both at the interface between test article and supporting structure. Stevens presented the coupled systems modal approach (CSMA), where simplified asparagus patch models (parallel-oscillator representation) of load and source are connected. The asparagus patch model consists of modal effective masses and spring stiffnesses associated with the natural frequencies. When the random acceleration vibration specification is given the CSMA method is suitable to compute the value of the parameter C^2. When no mathematical model of the source can be made available, estimations of the value C^2 can be find in literature. In this paper a probabilistic mathematical representation of the unknown source is proposed, such that the asparagus patch model of the source can be approximated. The chosen probabilistic design parameters have a uniform distribution. The computation of the value C^2 can be done in conjunction with the CSMA method, knowing the apparent mass of the load and the random acceleration specification at the interface between load and source, respectively. Data of two

  16. Accelerated Vibration Test of coolant channel components under simulated flow induced excitation

    Energy Technology Data Exchange (ETDEWEB)

    Meher, K.K., E-mail: kkmeher@barc.gov.in; Pandey, J.K., E-mail: jkpandey@barc.gov.in; RamaRao, A., E-mail: arr@barc.gov.in

    2016-04-15

    Highlights: • The present study deals with the issue of loosening of the nut in the Grayloc joint due to flow induced vibration and fret in the feeder pipes in contact due to differential creep in the neighbouring channels. • Accelerated test has been done on the Grayloc joint on simulated flow induced vibration to study the effect of loosening of the nut. • In the present accelerated test, the component has not been led to failure (loosening) and an estimation of its service life has been approached based on the severity of test. • The inverse square law approach based on PSD comparison for severity of test have been used to correlate the actual operational hours and the Laboratory test hours to verify the loosening of the Grayloc nut for the present study. • By inverse power law approach, the minimum number of reactor-hours equivalent to 80 h of testing is 46,080 h (5.26 full power years). - Abstract: The present study outlines the accelerated testing procedure of a Grayloc joint assembly for possible loosening of its nut due to flow induced vibration. The concern of the Grayloc nut getting loosened in the absence of a lock nut due to flow induced vibration and the resulting fretting in the feeder pipes in contact due to differential creep in the neighbouring channels has been addressed here. The severity of the test was decided based on actual site measurement under different operating flow conditions and comparison of power spectral density (PSD). The laboratory test results were extrapolated for estimation of life of the component under operating condition using inverse power law approach. The uniqueness of the accelerated test is that the component under test has not been led to failure for assessing its operating life unlike conventional accelerated testing. From the tests and analysis, it was deduced that 80 h of accelerated laboratory testing was equivalent to 5.26 full power years (46,080 h) of the reactor operating life. The test duration was

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

    Directory of Open Access Journals (Sweden)

    Muchun Yu

    2016-01-01

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

  18. Design and Performance Test of Locking Curved-Nut

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Min Cheol; Kang, Ho Sung; Kim, Do Yeop; Lee, Suk Yong; Lee, Eung Suk [Chungbuk Nat’l Univ., Cheongju (Korea, Republic of); Jeong, Hui Jong [Viblock Company, Cheongwon (Korea, Republic of)

    2017-03-15

    Many types of locking nut are commercializing in the various industries where has heavy vibration. Because Nut's loosing causes a serious accident. But the most locking nuts are too expensive as the complicate manufacturing process. In this study, we design the new type of locking nut, 'Curved-Nut' that is relatively simple making process. We study a relation between the elastic energy and the nut loosing mechanism. So it is analysed, the elastic energy of Curved-Nut comparing with the locking test. The Curved-Nut was manufactured on the commercial nut using a milling tool with horizontal cutting, one or two time under the nut. As the result, the more elastic energy the more prevent the loosing of the nut. We verified the performance of the loosing nut using the vibration testing equipment (NAS3350).

  19. Small and inconsistent effects of whole body vibration on athletic performance : a systematic review and meta-analysis

    NARCIS (Netherlands)

    Hortobagyi, Tibor; Lesinski, Melanie; Fernandez-del-Olmo, Miguel; Granacher, Urs

    We quantified the acute and chronic effects of whole body vibration on athletic performance or its proxy measures in competitive and/or elite athletes. Systematic literature review and meta-analysis. Whole body vibration combined with exercise had an overall 0.3 % acute effect on maximal voluntary

  20. The Shock Vibration Bulletin. Part 4. Structural Dynamics and Modal Test and Analysis

    Science.gov (United States)

    1987-01-01

    Feb. 1971. 17 16. B. Bresler, and A. C. Scordelis , ’Shear Strength of Reinforced Concrete Beams-,Series 100, Issue 13, Structure and Material Research...their adequacy. Dynamic analyses, choice of failure thresholds of failure are even harder to theories , and an accurate dynamic model are estimate...without experimental evidence. shown to be crucial in fulfilling the 29 71 L requirements. Vibration testing data are theories of failure have to be

  1. Force Limited Vibration Testing and Subsequent Redesign of the Naval Postgraduate School CubeSat Launcher

    Science.gov (United States)

    2014-06-01

    complex (e.g., Honeycomb ), this approach can significantly increase the cost of a satellite program. 3. Limit the responses of the satellite to match...LEFT BLANK xv LIST OF ACRONYMS AND ABBREVIATIONS ABC Aft Bulkhead Carrier ADaMSat AS&T Development and Maturation Satellite AFSPC Air Force Space...vibration testing FRF frequency response function GEMSat Government Experimental Multi- Satellite GRACE Government Rideshare Advanced Concepts Experiments

  2. High-damping-performance magnetorheological material for passive or active vibration control

    Science.gov (United States)

    Liu, Taixiang; Yang, Ke; Yan, Hongwei; Yuan, Xiaodong; Xu, Yangguang

    2016-10-01

    Optical assembly and alignment system plays a crucial role for the construction of high-power or high-energy laser facility, which attempts to ignite fusion reaction and go further to make fusion energy usable. In the optical assembly and alignment system, the vibration control is a key problem needs to be well handled and a material with higher damping performance is much desirable. Recently, a new kind of smart magneto-sensitive polymeric composite material, named magnetorheological plastomer (MRP), was synthesized and reported as a high-performance magnetorheological material and this material has a magneto-enhanced high-damping performance. The MRP behaves usually in an intermediate state between fluid-like magnetorheological fluid and solid-like magnetorheological elastomer. The state of MRP, as well as the damping performance of MRP, can be tuned by adjusting the ratio of hard segments and soft segments, which are ingredients to synthesize the polymeric matrix. In this work, a series of MRP are prepared by dispersing micron-sized, magneto-sensitive carbonyl iron powders with related additives into polyurethane-based, magnetically insensitive matrix. It is found that the damping performance of MRP depends much on magnetic strength, shear rate, carbonyl iron content and shear strain amplitude. Especially, the damping capacity of MRP can be tuned in a large range by adjusting external magnetic field. It is promising that the MRP will have much application in passive and active vibration control, such as vibration reduction in optical assembly and alignment system, vibration isolation or absorption in vehicle suspension system, etc.

  3. Gel performance in rheology and profile control under low-frequency vibration: coupling application of physical and chemical EOR techniques.

    Science.gov (United States)

    Zheng, Li Ming; Pu, Chun Sheng; Liu, Jing; Ma, Bo; Khan, Nasir

    2017-01-01

    Flowing gel plugging and low-frequency vibration oil extraction technology have been widely applied in low-permeability formation. High probability of overlapping in action spheres of two technologies might lead to poor operating efficiency during gel injection. Study on flowing gel rheological properties under low-frequency vibration was essential, which was carried out indoor with viscosity measurement. Potential dynamic mechanisms were analyzed for the rheological variation. Under low-frequency vibration, gel rheological properties were found to be obviously influenced, with vibration delaying gel cross-linking in induction period, causing a two-stage gel viscosity change in acceleration period, and decreasing gel strength in stable period. Surface of gel system under vibration presented different fluctuating phenomenon from initial harmonic vibrating to heterogeneous fluctuating (droplet separation might appear) to final harmonic vibrating again. Dynamic displacement in unconsolidated sand pack revealed that low-frequency vibration during gel injection might be a measure to achieve deep profile control, with the gel injection depth increased by 65.8 % compared with the vibration-free sample. At last, suggestions for field test were given in the paper to achieve lower injection friction and better gel plugging efficiency.

  4. Reflectors for SAR performance testing.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2008-01-01

    Synthetic Aperture Radar (SAR) performance testing and estimation is facilitated by observing the system response to known target scene elements. Trihedral corner reflectors and other canonical targets play an important role because their Radar Cross Section (RCS) can be calculated analytically. However, reflector orientation and the proximity of the ground and mounting structures can significantly impact the accuracy and precision with which measurements can be made. These issues are examined in this report.

  5. EFFECTS OF WHOLE BODY VIBRATION ON STRENGTH AND JUMPING PERFORMANCE IN VOLLEYBALL AND BEACH VOLLEYBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    J.A. Pérez-Turpin

    2014-10-01

    Full Text Available The primary aim of this study was to examine the effects of 6-week strength training with whole body vibration (WBV on leg strength and jumping performance in volleyball and beach volleyball players. Twenty-three sub-elite male volleyball (VB; n=12 and beach volleyball players (BVB; n=11 aged 21.2±3.0 years were divided into two groups and subjected to 6 weeks of strength training (three one-hour sessions per week: (I 12 players (6 VB and 6 BVB players underwent training with WBV (30-40 Hz, 1.7-2.5 mm, 3.0-5.7 g, and (II 11 players (6 VB and 5 BVB players underwent traditional strength training. Squat jump (SJ and countermovement squat jump (CMJ measurements by the Ergo Tester contact platform and maximum leg press test (1RM were conducted. Three-factor (2 time x 2 WBV use x 2 discipline analysis of variance for SJ, CMJ and 1RM revealed a significant time main effect (p<0.001, a WBV use effect (p<0.001 and a discipline effect (p<0.001. Significantly greater improvements in the SJ (p<0.001 and CMJ (p<0.001 and in 1RM (p<0.001 were found in the WBV training groups than in traditional training groups. Significant 3-way interaction effects (training, WBV use, discipline kind were also found for SJ, CMJ and 1RM (p=0.001, p<0.001, p=0.001, respectively. It can be concluded that implementation of 6-week WBV training in routine practice in volleyball and beach volleyball players increases leg strength more and leads to greater improvement in jump performance than traditional strength training, but greater improvements can be expected in beach volleyball players than in volleyball players.

  6. ZnO thin film piezoelectric MEMS vibration energy harvesters with two piezoelectric elements for higher output performance.

    Science.gov (United States)

    Wang, Peihong; Du, Hejun

    2015-07-01

    Zinc oxide (ZnO) thin film piezoelectric microelectromechanical systems (MEMS) based vibration energy harvesters with two different designs are presented. These harvesters consist of a silicon cantilever, a silicon proof mass, and a ZnO piezoelectric layer. Design I has a large ZnO piezoelectric element and Design II has two smaller and equally sized ZnO piezoelectric elements; however, the total area of ZnO thin film in two designs is equal. The ZnO thin film is deposited by means of radio-frequency magnetron sputtering method and is characterized by means of XRD and SEM techniques. These ZnO energy harvesters are fabricated by using MEMS micromachining. The natural frequencies of the fabricated ZnO energy harvesters are simulated and tested. The test results show that these two energy harvesters with different designs have almost the same natural frequency. Then, the output performance of different ZnO energy harvesters is tested in detail. The effects of series connection and parallel connection of two ZnO elements on the load voltage and power are also analyzed. The experimental results show that the energy harvester with two ZnO piezoelectric elements in parallel connection in Design II has higher load voltage and higher load power than the fabricated energy harvesters with other designs. Its load voltage is 2.06 V under load resistance of 1 MΩ and its maximal load power is 1.25 μW under load resistance of 0.6 MΩ, when it is excited by an external vibration with frequency of 1300.1 Hz and acceleration of 10 m/s(2). By contrast, the load voltage of the energy harvester of Design I is 1.77 V under 1 MΩ resistance and its maximal load power is 0.98 μW under 0.38 MΩ load resistance when it is excited by the same vibration.

  7. Research on the Random Shock Vibration Test Based on the Filter-X LMS Adaptive Inverse Control Algorithm

    Directory of Open Access Journals (Sweden)

    Wang Wei

    2016-01-01

    Full Text Available The related theory and algorithm of adaptive inverse control were presented through the research which pointed out the adaptive inverse control strategy could effectively eliminate the noise influence on the system control. Proposed using a frequency domain filter-X LMS adaptive inverse control algorithm, and the control algorithm was applied to the two-exciter hydraulic vibration test system of random shock vibration control process and summarized the process of the adaptive inverse control strategies in the realization of the random shock vibration test. The self-closed-loop and field test show that using the frequency-domain filter-X LMS adaptive inverse control algorithm can realize high precision control of random shock vibration test.

  8. Statistical correlation analysis for comparing vibration data from test and analysis

    Science.gov (United States)

    Butler, T. G.; Strang, R. F.; Purves, L. R.; Hershfeld, D. J.

    1986-01-01

    A theory was developed to compare vibration modes obtained by NASTRAN analysis with those obtained experimentally. Because many more analytical modes can be obtained than experimental modes, the analytical set was treated as expansion functions for putting both sources in comparative form. The dimensional symmetry was developed for three general cases: nonsymmetric whole model compared with a nonsymmetric whole structural test, symmetric analytical portion compared with a symmetric experimental portion, and analytical symmetric portion with a whole experimental test. The theory was coded and a statistical correlation program was installed as a utility. The theory is established with small classical structures.

  9. Serological tests for diagnosis and staging of hand-arm vibration syndrome (HAVS).

    Science.gov (United States)

    Kao, Dennis S; Yan, Ji-Geng; Zhang, Lin-Ling; Kaplan, Rachel E; Riley, Danny A; Matloub, Hani S

    2008-06-01

    The current gold standard for the diagnosis and staging of hand-arm vibration syndrome (HAVS) is the Stockholm workshop scale, which is subjective and relies on the patient's recalling ability and honesty. Therefore, great potentials exist for diagnostic and staging errors. The purpose of this study is to determine if objective serum tests, such as levels of soluble thrombomodulin (sTM) and soluble intercellular adhesion molecule-1 (sICAM-1), may be used in the diagnosis and staging of HAVS. Twenty two nonsmokers were divided into a control group (n = 11) and a vibration group (n = 11). The control group included subjects without history of frequent vibrating tool use. The vibration group included construction workers with average vibrating tool use of 12.2 years. All were classified according to the Stockholm workshop scale (SN, sensorineural symptoms; V, vascular symptoms. SN0, no numbness; SN1, intermittent numbness; SN2, reduced sensory perception; SN3, reduced tactile discrimination; V0, no vasospasmic attacks; V1, intermittent vasospasm involving distal phalanges; V2, intermittent vasospasm extending to middle phalanges; V3, intermittent vasospasm extending to proximal phalanges; V4, skin atrophy/necrosis). All control subjects were SN0 V0. Seven out of 11 vibration subjects were SN1 V1, and 4 out of 11 were SN1 V2. A 10-cm(3) sample of venous blood was collected from each subject. The sTM and sICAM-1 levels were determined by enzyme-linked immunosorbent assay. The mean plasma sTM levels were as follows: control group = 2.93 +/- 0.47 ng/ml, and vibration group = 3.61 +/- 0.24 ng/ml. The mean plasma sICAM-1 levels were as follows: control group = 218.8 +/- 54.1 ng/ml, and vibration group = 300.3 +/- 53.2 ng/ml. The sTM and sICAM-1 differences between control and vibration groups were statistically significant (p Stockholm workshop scale, mean plasma sTM levels were SN0 V0 group = 2.93 +/- 0.47 ng/ml, SN1 V1 group = 3.59 +/- 0.25 ng/ml, and SN1 V2 group = 3

  10. The effect of pranayama on test anxiety and test performance

    Directory of Open Access Journals (Sweden)

    Azadeh Nemati

    2013-01-01

    Conclusions: Pranayama seems to have a significant positive effect on test anxiety and test performance. It could be used as an important technique by students prior to their examinations, to reduce their test anxiety and increase their test performance.

  11. Sound vibration signal processing for detection and identification detonation (knock) to optimize performance Otto engine

    Science.gov (United States)

    Sujono, A.; Santoso, B.; Juwana, W. E.

    2016-03-01

    Problems of detonation (knock) on Otto engine (petrol engine) is completely unresolved problem until now, especially if want to improve the performance. This research did sound vibration signal processing engine with a microphone sensor, for the detection and identification of detonation. A microphone that can be mounted is not attached to the cylinder block, that's high temperature, so that its performance will be more stable, durable and inexpensive. However, the method of analysis is not very easy, because a lot of noise (interference). Therefore the use of new methods of pattern recognition, through filtration, and the regression function normalized envelope. The result is quite good, can achieve a success rate of about 95%.

  12. Effect of vibration frequency on microstructure and performance of high chromium cast iron prepared by lost foam casting

    Directory of Open Access Journals (Sweden)

    Wen-qi Zou

    2016-07-01

    Full Text Available In the present research, high chromium cast irons (HCCIs were prepared using the lost foam casting (LFC process. To improve the wear resistance of the high chromium cast irons (HCCIs, mechanical vibration was employed during the solidification of the HCCIs. The effects of vibration frequency on the microstructure and performance of the HCCIs under as-cast, as-quenched and as-tempered conditions were investigated. The results indicated that the microstructures of the LFC-produced HCCIs were refined due to the introduction of mechanical vibration, and the hardness was improved compared to that of the alloy without vibration. However, only a slight improvement in hardness was found in spite of the increase of vibration frequency. In contrast, the impact toughness of the as-tempered HCCIs increased with an increase in the vibration frequency. In addition, the wear resistance of the HCCIs was improved as a result of the introduction of vibration and increased with an increase in the vibration frequency.

  13. Understanding how the placement of an asymmetric vibration damping tool within drilling while underreaming can influence performance and reliability

    Energy Technology Data Exchange (ETDEWEB)

    Kabbara, Alan; McCarthy, John; Burnett, Timm; Forster, Ian [National Oilwell Varco Downhole Ltd. (NOV), Houston, TX (United States)

    2012-07-01

    This paper describes the work, on test rigs and full-scale drilling rigs, carried out with respect to placement of an Asymmetric Vibration Damping Tool (AVDT) within drilling while under reaming operations. An AVDT, by virtue of the forward synchronous motion imposed on the drill string, offers benefits in minimizing down hole vibration-related tool failures and therefore maximizing rate of penetration (ROP). Of interest in using the AVDT is the tendency to minimize stick slip by means of the parasitic torque it generates. This is of particular importance during under reaming operations. While under reaming, stick slip can result in low (ROP) and potentially an increased incidence of down hole tool failures. The use of an AVDT in these operations has been shown to significantly reduce stick slip. However, due to the forward synchronous motion caused by the AVDT, there is the potential to cause eccentric wear to the Bottom Hole Assembly (BHA) components in the vicinity of the AVDT. If allowed to progress, this eccentric wear can cause a reduction in down hole tool life and drilling performance. Eliminating eccentric wear would be beneficial in reducing repair costs, extending component life and further improving drilling performance. To minimize eccentric wear and maximize drilling performance, the placement of the AVDT within the BHA is critical. This paper describes how the placement of intermediate stabilizers between the AVDT and the under reamer can minimize eccentric wear to the under reamer and the adjacent drill string due to the forward synchronous whirl induced by the AVDT. This approach allows the full benefits of the AVDT to be recognized while reducing the potentially damaging effects of eccentric wear to other BHA components. The work has drawn upon small-scale rig testing, full-scale testing at the Ullrigg test facility in Norway and from real-world drilling and under reaming operations in the USA. (author)

  14. An experimental study of vibration attenuation performance of several on-grade slab configurations

    Science.gov (United States)

    Amick, H.; Wongprasert, N.; Montgomery, J.; Haswell, P.; Lynch, D.

    2005-08-01

    There are several instances in the literature in which particular positions are taken regarding the nature of the floor supporting sensitive equipment such as advanced electron microscopes. Assertions are made that one methodology is better than another at reducing vibrations. However, very little experimental evidence has been provided to support those positions. This paper presents the results of an experimental in situ study of several slab configurations at a single location-the site of a nanotechnology facility that was about to be constructed at the University of Alberta. Three configurations were constructed: (a) a large solid slab of moderate thickness; (b) a smaller slab "island" of greater thickness (900 mm) surrounded by a thinner slab, both resting directly on soil and separated by a gap; and (c) another island of the same dimensions, but resting on four concrete piles. The three locations were instrumented and measurements taken allowing comparison of the performance of these configurations at attenuating ambient vibrations and vibrations due to a nearby heel-drop impulse. The ranking of the three must be based upon excitation type and frequency range of concern.

  15. Experimental Analysis of Mast Lifting and Bending Forces on Vibration Patterns Before and After Pinion Reinstallation in an OH-58 Transmission Test Rig

    Science.gov (United States)

    Huff, Edward M.; Lewicki, David G.; Tumer, Irem Y.; Decker, Harry; Barszez, Eric; Zakrajsek, James J.; Norvig, Peter (Technical Monitor)

    2000-01-01

    As part of a collaborative research program between NASA Ames Research Center (ARC), NASA Glenn Research Center (GRC), and the US Army Laboratory, a series of experiments is being performed in GRC's 500 HP OH-58 Transmission Test Rig facility and ARC's AH-I Cobra and OH-58c helicopters. The findings reported in this paper were drawn from Phase-I of a two-phase test-rig experiment, and are focused on the vibration response of an undamaged pinion gear operating in the transmission test rig. To simulate actual flight conditions, the transmission system was run at three torque levels, as well as two mast lifting and two mast bending levels. The test rig was also subjected to disassembly and reassembly of the main pinion housing to simulate the effect of maintenance operations. An analysis of variance based on the total power of the spectral distribution indicates the relative effect of each experimental factor, including Wong interactions with torque. Reinstallation of the main pinion assembly is shown to introduce changes in the vibration signature, suggesting the possibility of a strong effect of maintenance on HUMS design and use. Based on these results, further research will be conducted to compare these vibration responses with actual OH58c helicopter transmission vibration patterns.

  16. Test Performance Related Dysfunctional Beliefs

    Directory of Open Access Journals (Sweden)

    Recep TÜTÜNCÜ

    2012-11-01

    Full Text Available Objective: Examinations by using tests are very frequently used in educational settings and successful studying before the examinations is a complex matter to deal with. In order to understand the determinants of success in exams better, we need to take into account not only emotional and motivational, but also cognitive aspects of the participants such as dysfunctional beliefs. Our aim is to present the relationship between candidates’ characteristics and distorted beliefs/schemata just before an examination. Method: The subjects of the study were 30 female and 30 male physicians who were about to take the medical specialization exam (MSE in Turkey. Dysfunctional Attitude Scale (DAS and Young Schema Questionnaire Short Form (YSQ-SF were applied to the subjects. The statistical analysis was done using the F test, Mann-Whitney, Kruskal-Wallis, chi-square test and spearman’s correlation test. Results: It was shown that some of the DAS and YSQ-SF scores were significantly higher in female gender, in the group who could not pass the exam, who had repetitive examinations, who had their first try taking an examination and who were unemployed at the time of the examination. Conclusion: Our findings indicate that candidates seeking help before MSE examination could be referred for cognitive therapy or counseling even they do not have any psychiatric diagnosis due to clinically significant cognitive distortion. Measurement and treatment of cognitive distortions that have negative impact on MSE performance may improve the cost-effectiveness and mental well being of the young doctors.

  17. Effects of whole body vibration training on muscle strength and sprint performance in sprint-trained athletes.

    Science.gov (United States)

    Delecluse, C; Roelants, M; Diels, R; Koninckx, E; Verschueren, S

    2005-10-01

    Despite the expanding use of Whole Body Vibration training among athletes, it is not known whether adding Whole Body Vibration training to the conventional training of sprint-trained athletes will improve speed-strength performance. Twenty experienced sprint-trained athletes (13 male symbol, 7 female symbol, 17-30 years old) were randomly assigned to a Whole Body Vibration group (n=10: 6 male symbol and 4 female symbol) or a Control group (n=10: 7 male symbol, 3 female symbol). During a 5-week experimental period all subjects continued their conventional training program, but the subjects of the Whole Body Vibration group additionally performed three times weekly a Whole Body Vibration training prior to their conventional training program. The Whole Body Vibration program consisted of unloaded static and dynamic leg exercises on a vibration platform (35-40 Hz, 1.7-2.5 mm, Power Plate). Pre and post isometric and dynamic (100 degrees/s) knee-extensor and -flexor strength and knee-extension velocity at fixed resistances were measured by means of a motor-driven dynamometer (Rev 9000, Technogym). Vertical jump performance was measured by means of a contact mat. Force-time characteristics of the start action were assessed using a load cell mounted on each starting block. Sprint running velocity was recorded by means of a laser system. Isometric and dynamic knee-extensor and knee-flexor strength were unaffected (p>0.05) in the Whole Body Vibration group and the Control group. As well, knee-extension velocity remained unchanged (p>0.05). The duration of the start action, the resulting start velocity, start acceleration, and sprint running velocity did not change (>0.05) in either group. In conclusion, this specific Whole Body Vibration protocol of 5 weeks had no surplus value upon the conventional training program to improve speed-strength performance in sprint-trained athletes.

  18. Small-scale rotor test rig capabilities for testing vibration alleviation algorithms

    Science.gov (United States)

    Jacklin, Stephen A.; Leyland, Jane Anne

    1987-01-01

    A test was conducted to assess the capabilities of a small scale rotor test rig for implementing higher harmonic control and stability augmentation algorithms. The test rig uses three high speed actuators to excite the swashplate over a range of frequencies. The actuator position signals were monitored to measure the response amplitudes at several frequencies. The ratio of response amplitude to excitation amplitude was plotted as a function of frequency. In addition to actuator performance, acceleration from six accelerometers placed on the test rig was monitored to determine whether a linear relationship exists between the harmonics of N/Rev control input and the least square error (LSE) identification technique was used to identify local and global transfer matrices for two rotor speeds at two batch sizes each. It was determined that the multicyclic control computer system interfaced very well with the rotor system and kept track of the input accelerometer signals and their phase angles. However, the current high speed actuators were found to be incapable of providing sufficient control authority at the higher excitation frequencies.

  19. Where Lab Tests Are Performed

    Science.gov (United States)

    ... your own home, where you might take a pregnancy test or monitor your blood glucose levels. Many of ... of-care tests are blood glucose monitoring , home pregnancy tests , and blood chemistry tests . Other point-of-care ...

  20. Ground Vibration Test Planning and Pre-Test Analysis for the X-33 Vehicle

    Science.gov (United States)

    Bedrossian, Herand; Tinker, Michael L.; Hidalgo, Homero

    2000-01-01

    This paper describes the results of the modal test planning and the pre-test analysis for the X-33 vehicle. The pre-test analysis included the selection of the target modes, selection of the sensor and shaker locations and the development of an accurate Test Analysis Model (TAM). For target mode selection, four techniques were considered, one based on the Modal Cost technique, one based on Balanced Singular Value technique, a technique known as the Root Sum Squared (RSS) method, and a Modal Kinetic Energy (MKE) approach. For selecting sensor locations, four techniques were also considered; one based on the Weighted Average Kinetic Energy (WAKE), one based on Guyan Reduction (GR), one emphasizing engineering judgment, and one based on an optimum sensor selection technique using Genetic Algorithm (GA) search technique combined with a criteria based on Hankel Singular Values (HSV's). For selecting shaker locations, four techniques were also considered; one based on the Weighted Average Driving Point Residue (WADPR), one based on engineering judgment and accessibility considerations, a frequency response method, and an optimum shaker location selection based on a GA search technique combined with a criteria based on HSV's. To evaluate the effectiveness of the proposed sensor and shaker locations for exciting the target modes, extensive numerical simulations were performed. Multivariate Mode Indicator Function (MMIF) was used to evaluate the effectiveness of each sensor & shaker set with respect to modal parameter identification. Several TAM reduction techniques were considered including, Guyan, IRS, Modal, and Hybrid. Based on a pre-test cross-orthogonality checks using various reduction techniques, a Hybrid TAM reduction technique was selected and was used for all three vehicle fuel level configurations.

  1. Development of a sine-dwell ground vibration test (GVT) system

    CSIR Research Space (South Africa)

    Van Zyl, Lourens H

    2006-02-27

    Full Text Available Vibration Test (GVT) System Presented at CSIR Research and Innovation Conference: 27 - 28 February 2006 DPSS Mr Louw van Zyl Mr Erik Wegman 27 February 2006 Slide 2 © CSIR 2006 www.csir.co.za Agenda • Introduction Why ground... stream_source_info VanZyl_2006.pdf.txt stream_content_type text/plain stream_size 9765 Content-Encoding UTF-8 stream_name VanZyl_2006.pdf.txt Content-Type text/plain; charset=UTF-8 Development of a Sine-Dwell Ground...

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

    Energy Technology Data Exchange (ETDEWEB)

    Kassir, M.K.; Park, Y.J.; Hofmayer, C.H.; Bandyopadhyay, K.K.; Shteyngart, S. [Brookhaven National Lab., Upton, NY (United States)

    1993-08-01

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

  3. Testing techniques and comparisons between theory and test for vibration modes of ring stiffened truncated-cone shells.

    Science.gov (United States)

    Naumann, E. C.

    1972-01-01

    Vibration tests were carried out on truncated-cone shells with widely spaced ring stiffeners. The models were excited by an air shaker for LF modes and by small electrodynamic shakers for HF modes. The Novozhilov thin shell theory according to which a ring is an assembly of an arbitrary number of segments, each being a short truncated-cone shell of uniform thickness, is used in the analysis of the results. A mobile, noncontacting, displacement-sensitive sensor system developed by the author was used in the tests. Tests results are given for a free-free 60-deg cone and for a clamped-free 60-deg cone. The tests are characterized as having considerable value for the classification of prevalent multimode responses in shells of this type.

  4. Whole-Body Vibration Training Effect on Physical Performance and Obesity in Mice

    OpenAIRE

    Huang, Chi-Chang; Tseng, Tzu-Ling; Huang, Wen-Ching; Chung, Yi-Hsiu; Chuang, Hsiao-Li; Wu, Jyh-Horng

    2014-01-01

    The purpose of this study was to verify the beneficial effects of whole-body vibration (WBV) training on exercise performance, physical fatigue and obesity in mice with obesity induced by a high-fat diet (HFD). Male C57BL/6 mice were randomly divided into two groups: normal group (n=6), fed standard diet (control), and experimental group (n=18), fed a HFD. After 4-week induction, followed by 6-week WBV of 5 days per week, the 18 obese mice were divided into 3 groups (n=6 per group): HFD with ...

  5. 40 CFR 60.8 - Performance tests.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Performance tests. 60.8 Section 60.8... PERFORMANCE FOR NEW STATIONARY SOURCES General Provisions § 60.8 Performance tests. (a) Except as specified in... conduct performance test(s) and furnish the Administrator a written report of the results of such...

  6. Adding whole body vibration to preconditioning exercise increases subsequent on-ice sprint performance in ice-hockey players.

    Science.gov (United States)

    Rønnestad, Bent R; Slettaløkken, Gunnar; Ellefsen, Stian

    2016-04-01

    The phenomenon postactivation potentiation can possibly be used to acutely improve sprint performance. The purpose of this study was to investigate the effect of body-loaded half-squats with added whole body vibration (WBV) on subsequent 20 m on-ice sprint performance. Fifteen male ice-hockey players performed 4 test sessions on separate days and in a randomized order. Two of this test sessions were with WBV and 2 were with noWBV and the best sprint time was used to determine effectiveness. Each test session included preconditioning 30 seconds half-squat exercise, 2 of which were supplemented with 50 Hz WBV at a amplitude of 3 mm. One minute after the cessation of the preconditioning exercise, the 20 m sprint test was performed. Intermediate time was sampled after 10 m. Preconditioning exercise performed with 50 Hz WBV resulted in superior 10 m and 20 m sprint performance compared to preconditioning exercise performed without WBV (1.84 6 0.10 seconds vs. 1.89 6 0.10 seconds and 3.14 6 0.13 vs. 3.17 6 0.13 seconds, respectively, p # 0.01). There was no difference between the protocols in perceived well-being of the legs before the warm-up or after the warm up (p = 0.3). However, there was an improved well-being in the legs immediately after the preconditioning exercise with WBV (p , 0.05). In conclusion, preconditioning exercise performed with WBV at 50 Hz seems to enhance on-ice sprint performance in ice-hockey players. This suggests that coaches can incorporate such exercise into the preparation to specific sprint training to improve the quality of the training.

  7. The Skull Vibration-Induced Nystagmus Test of Vestibular Function—A Review

    Science.gov (United States)

    Dumas, Georges; Curthoys, Ian S.; Lion, Alexis; Perrin, Philippe; Schmerber, Sébastien

    2017-01-01

    A 100-Hz bone-conducted vibration applied to either mastoid induces instantaneously a predominantly horizontal nystagmus, with quick phases beating away from the affected side in patients with a unilateral vestibular loss (UVL). The same stimulus in healthy asymptomatic subjects has little or no effect. This is skull vibration-induced nystagmus (SVIN), and it is a useful, simple, non-invasive, robust indicator of asymmetry of vestibular function and the side of the vestibular loss. The nystagmus is precisely stimulus-locked: it starts with stimulation onset and stops at stimulation offset, with no post-stimulation reversal. It is sustained during long stimulus durations; it is reproducible; it beats in the same direction irrespective of which mastoid is stimulated; it shows little or no habituation; and it is permanent—even well-compensated UVL patients show SVIN. A SVIN is observed under Frenzel goggles or videonystagmoscopy and recorded under videonystagmography in absence of visual-fixation and strong sedative drugs. Stimulus frequency, location, and intensity modify the results, and a large variability in skull morphology between people can modify the stimulus. SVIN to 100 Hz mastoid stimulation is a robust response. We describe the optimum method of stimulation on the basis of the literature data and testing more than 18,500 patients. Recent neural evidence clarifies which vestibular receptors are stimulated, how they cause the nystagmus, and why the same vibration in patients with semicircular canal dehiscence (SCD) causes a nystagmus beating toward the affected ear. This review focuses not only on the optimal parameters of the stimulus and response of UVL and SCD patients but also shows how other vestibular dysfunctions affect SVIN. We conclude that the presence of SVIN is a useful indicator of the asymmetry of vestibular function between the two ears, but in order to identify which is the affected ear, other information and careful clinical judgment are

  8. Performance and Environmental Test Results of the High Voltage Hall Accelerator Engineering Development Unit

    Science.gov (United States)

    Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Shastry, Rohit; Pinero, Luis; Peterson, Todd; Mathers, Alex

    2012-01-01

    NASA Science Mission Directorate's In-Space Propulsion Technology Program is sponsoring the development of a 3.5 kW-class engineering development unit Hall thruster for implementation in NASA science and exploration missions. NASA Glenn and Aerojet are developing a high fidelity high voltage Hall accelerator that can achieve specific impulse magnitudes greater than 2,700 seconds and xenon throughput capability in excess of 300 kilograms. Performance, plume mappings, thermal characterization, and vibration tests of the high voltage Hall accelerator engineering development unit have been performed. Performance test results indicated that at 3.9 kW the thruster achieved a total thrust efficiency and specific impulse of 58%, and 2,700 sec, respectively. Thermal characterization tests indicated that the thruster component temperatures were within the prescribed material maximum operating temperature limits during full power thruster operation. Finally, thruster vibration tests indicated that the thruster survived the 3-axes qualification full-level random vibration test series. Pre and post-vibration test performance mappings indicated almost identical thruster performance. Finally, an update on the development progress of a power processing unit and a xenon feed system is provided.

  9. Monitoring vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Tiryaki, B. [Hacettepe University (Turkey). Dept. of Mining Engineering

    2003-12-01

    The paper examines the prediction and optimisation of machine vibrations in longwall shearers. Underground studies were carried out at the Middle Anatolian Lignite Mine, between 1993 and 1997. Several shearer drums with different pick lacing arrangements were designed and tested on double-ended ranging longwall shearers employed at the mine. A computer program called the Vibration Analysis Program (VAP) was developed for analysing machine vibrations in longwall shearers. Shearer drums that were tested underground, as well as some provided by leading manufacturers, were analyzed using these programs. The results of the experiments and computer analyses are given in the article. 4 refs., 9 figs.

  10. Trinity Acceptance Tests Performance Summary.

    Energy Technology Data Exchange (ETDEWEB)

    Rajan, Mahesh [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    Ensuring Real Applications perform well on Trinity is key to success. Four components: ASC applications, Sustained System Performance (SSP), Extra-Large MiniApplications problems, and Micro-benchmarks.

  11. Stereotype Threat, Test Anxiety, and Mathematics Performance

    Science.gov (United States)

    Tempel, Tobias; Neumann, Roland

    2014-01-01

    We investigated the combined effects of stereotype threat and trait test anxiety on mathematics test performance. Stereotype threat and test anxiety interacted with each other in affecting performance. Trait test anxiety predicted performance only in a diagnostic condition that prevented stereotype threat by stereotype denial. A state measure of…

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

    Science.gov (United States)

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

    2013-07-01

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

  13. Confidence and Cognitive Test Performance

    Science.gov (United States)

    Stankov, Lazar; Lee, Jihyun

    2008-01-01

    This article examines the nature of confidence in relation to abilities, personality, and metacognition. Confidence scores were collected during the administration of Reading and Listening sections of the Test of English as a Foreign Language Internet-Based Test (TOEFL iBT) to 824 native speakers of English. Those confidence scores were correlated…

  14. Dynamical Performances of a Vibration Absorber for Continuous Structure considering Time-Delay Coupling

    Directory of Open Access Journals (Sweden)

    Xiuting Sun

    2016-01-01

    Full Text Available The nonlinear effect incurred by time delay in vibration control is investigated in this study via a vibration absorber coupled with a continuous beam structure. The stability of the vibration absorber coupled structure system with time-delay coupling is firstly studied, which provides a general guideline for the potential time delay to be introduced to the system. Then it is shown that there is a specific region for the time delay which can bring bifurcation modes to the dynamic response of the coupling system, and the vibration energy at low frequencies can be transferred or absorbed due to the bifurcation mode and the vibration in the corresponding frequency range is thus suppressed. The nonlinear mechanism of this vibration suppression incurred by the coupling time delay is discussed in detail, which provides a novel and alternative approach to the analysis, design, and control of vibration absorbers in engineering practice.

  15. Determining the optimal whole-body vibration dose-response relationship for muscle performance.

    Science.gov (United States)

    Da Silva-Grigoletto, Marzo E; De Hoyo, Moisés; Sañudo, Borja; Carrasco, Luis; García-Manso, Juan M

    2011-12-01

    Da Silva-Grigoletto, ME, de Hoyo, M, Sañudo, B, Corrales, L, and García-Manso, JM. Determining the optimal whole-body vibration dose-response relationship for muscle performance. J Strength Cond Res 25(12): 3326-3333, 2011-The aim of this investigation was twofold: first, to determine the optimal duration of a single whole-body vibration (WBV) exposure (phase 1) and second to find out the ideal number of sets per intervention to maximize muscle performance (phase 2). All participants were young (age: 19.4 ± 1.6 years), healthy, physically active men. In both studies, a 30-Hz frequency and a 4-mm peak-to-peak displacement were used. In phase 1, subjects (n = 30) underwent 3 sets of different durations (30, 60, and 90 seconds), whereas in phase 2, subjects (n = 27) underwent 3 interventions where the duration remained fixed at 60 seconds, and the number of sets performed (3, 6, or 9) was modified. The recovery time between sets was set at 2 minutes. In all interventions, each set consisted of 1 isometric repetition in a squat position with knees flexed at 100°. Before and after each session, jump height (countermovement jump [CMJ] and squat jump [SJ]) and power output in half squat (90° knee flexion) were assessed. In phase 1, an improvement in jump ability and power output was observed after the 30- and 60-second intervention (p effect for the program of 6 sets (p < 0.05). In conclusion, a WBV intervention consisting of six 60-second sets produces improved muscle performance measured by SJ, CMJ, and power output.

  16. Active vibration control for a smart panel with enhanced acoustic performances

    Science.gov (United States)

    Ripamonti, Francesco; Baro, Simone; Molgora, Manuel

    2017-04-01

    The spread of smart structures has recorded a significant increase during the last decades. Nowadays these solutions are applied in various fields such as aerospace, automotive and civil constructions. This kind of structures was born in the past in order to cope with the high vibrations that every lightweight structure has to face. In order to reduce weight designers usually decide to use very thin and lightweight structures. In the automotive field, for example, a reduced fuel consumption is obtained employing lightweight materials. However, in general a worsening of the vibroacoustic comfort is obtained with undesired vibrations that can be really annoying for passengers and dangerous for the structure itself. This work presents an innovative smart plate that is able to actively vary its dynamic properties, by means of an IMSC control logic, in order to improve the acoustic performances. An investigation about the system response in the high frequency range allowed to assess the behavior in terms of absorption, reflection coefficient and transmission loss.

  17. The effects of whole-body vibration on the Wingate test for anaerobic power when applying individualized frequencies.

    Science.gov (United States)

    Surowiec, Rachel K; Wang, Henry; Nagelkirk, Paul R; Frame, Jeffrey W; Dickin, D Clark

    2014-07-01

    Recently, individualized frequency (I-Freq) has been introduced with the notion that athletes may elicit a greater reflex response at differing levels (Hz) of vibration. The aim of the study was to evaluate acute whole-body vibration as a feasible intervention to increase power in trained cyclists and evaluate the efficacy of using I-Freq as an alternative to 30Hz, a common frequency seen in the literature. Twelve highly trained, competitive male cyclists (age, 29.9 ± 10.0 years; body height, 175.4 ± 7.8 cm; body mass, 77.3 ± 13.9 kg) participated in the study. A Wingate test for anaerobic power was administered on 3 occasions: following a control of no vibration, 30 Hz, or I-freq. Measures of peak power, average power (AP), and the rate of fatigue were recorded and compared with the vibration conditions using separate repeated measures analysis of variance. Peak power, AP, and the rate of fatigue were not significantly impacted by either the 30 Hz or I-Freq vibration interventions (p > 0.05). Given the trained status of the individuals in this study, the ability to elicit an acute response may have been muted. Future studies should further refine the vibration parameters used and assess changes in untrained or recreationally trained populations.

  18. Force Limiting Vibration Tests Evaluated from both Ground Acoustic Tests and FEM Simulations of a Flight Like Vehicle System Assembly

    Science.gov (United States)

    Smith, Andrew; LaVerde, Bruce; Waldon, James; Hunt, Ron

    2014-01-01

    Marshall Space Flight Center has conducted a series of ground acoustic tests with the dual goals of informing analytical judgment, and validating analytical methods when estimating vibroacoustic responses of launch vehicle subsystems. The process of repeatedly correlating finite element-simulated responses with test-measured responses has assisted in the development of best practices for modeling and post-processing. In recent work, force transducers were integrated to measure interface forces at the base of avionics box equipment. Other force data was indirectly measured using strain gauges. The combination of these direct and indirect force measurements has been used to support and illustrate the advantages of implementing the Force Limiting approach for equipment qualification tests. The comparison of force response from integrated system level tests to measurements at the same locations during component level vibration tests provides an excellent illustration. A second comparison of the measured response cases from the system level acoustic tests to finite element simulations has also produced some principles for assessing the suitability of Finite Element Models (FEMs) for making vibroacoustics estimates. The results indicate that when FEM models are employed to guide force limiting choices, they should include sufficient detail to represent the apparent mass of the system in the frequency range of interest.

  19. Active vibration control testing of the SPICES program: final demonstration article

    Science.gov (United States)

    Dunne, James P.; Jacobs, Jack H.

    1996-05-01

    The Synthesis and Processing of Intelligent Cost Effective Structures (SPICES) Program is a partnership program sponsored by the Advanced Research Projects Agency. The mission of the program is to develop cost effective material processing and synthesis technologies to enable new products employing active vibration suppression and control devices to be brought to market. The two year program came to fruition in 1995 through the fabrication of the final smart components and testing of an active plate combined with two trapezoidal rails, forming an active mount. Testing of the SPICES combined active mount took place at McDonnell Douglas facilities in St. Louis, MO, in October-December 1995. Approximately 15 dB reduction in overall response of a motor mounted on the active structure was achieved. Further details and results of the SPICES combined active mount demonstration testing are outlined. Results of numerous damping and control strategies that were developed and employed in the testing are presented, as well as aspects of the design and fabrication of the SPICES active mount components.

  20. Test Performance Related Dysfunctional Beliefs

    Directory of Open Access Journals (Sweden)

    Recep TÜTÜNCÜ

    2012-08-01

    Conclusion: Our findings indicate that candidates seeking help before MSE examination could be referred for cognitivetherapy or counseling even they do not have any psychiatric diagnosis due to clinically significant cognitive distortion.Measurement and treatment of cognitive distortions that have negative impact on MSE performance may improve thecost-effectiveness and mental well being of the oung doctors. [JCBPR 2012; 1(2.000: 90-97

  1. The Effect of Whole Body Vibration Training and Detraining Periods on Neuromuscular Performance in Male Older People

    Directory of Open Access Journals (Sweden)

    Ali Abbasi

    2011-07-01

    Full Text Available Objectives: This study aimed to evaluatethe the effect of eight weeks whole body vibration training (WBVT and detraining periods on neuromuscular performance male healthy older people. Methods & Materials: Thirty male subjects (70±9.6 years old were randomly allocated into two groups of WBVT and control (n=15 per group. Timed Up & Go and 5-Chair stand tests, as indicators of neuromuscular performance in older subjects, were taken as pretest and posttest and also after four, six, and eight weeks of detraining. Results: Results of Repeated-measure ANOVA and one-way ANOVA showed that neuromuscular performance improved significantly in WBVT group (P<0.05. There were also significant differences between posttest and six and eight weeks of detraining periods in WBVTgroup (P<0.05. Conclusion: WBVT could affect neuromuscular performance in healthy subjects and reduce the probability of falling among them. However, the effects of this training are not persistent, goes back to the early levels after six weeks of detraining. Hence, it is possible that WBVT can be recommended as a safe balance training to older people.

  2. THE POTENTIAL NEURAL MECHANISMS OF ACUTE INDIRECT VIBRATION

    Directory of Open Access Journals (Sweden)

    Darryl J. Cochrane

    2011-03-01

    Full Text Available There is strong evidence to suggest that acute indirect vibration acts on muscle to enhance force, power, flexibility, balance and proprioception suggesting neural enhancement. Nevertheless, the neural mechanism(s of vibration and its potentiating effect have received little attention. One proposal suggests that spinal reflexes enhance muscle contraction through a reflex activity known as tonic vibration stretch reflex (TVR, which increases muscle activation. However, TVR is based on direct, brief, and high frequency vibration (>100 Hz which differs to indirect vibration, which is applied to the whole body or body parts at lower vibration frequency (5-45 Hz. Likewise, muscle tuning and neuromuscular aspects are other candidate mechanisms used to explain the vibration phenomenon. But there is much debate in terms of identifying which neural mechanism(s are responsible for acute vibration; due to a number of studies using various vibration testing protocols. These protocols include: different methods of application, vibration variables, training duration, exercise types and a range of population groups. Therefore, the neural mechanism of acute vibration remain equivocal, but spinal reflexes, muscle tuning and neuromuscular aspects are all viable factors that may contribute in different ways to increasing muscular performance. Additional research is encouraged to determine which neural mechanism(s and their contributions are responsible for acute vibration. Testing variables and vibration applications need to be standardised before reaching a consensus on which neural mechanism(s occur during and post-vibration

  3. 2009 Ford Mustang Performance Test

    Directory of Open Access Journals (Sweden)

    Daniel Fernandes

    2009-01-01

    Full Text Available Our goal is to find the time required for a 2009 Ford Mustang to accelerate from rest to 88 feet per second. We begin with three equations involving force, velocity, and force inverse, which is a value derived from Newton's Law, F=ma. The Mustang has three gears with three different gear ratios that must be used as the car accelerates. We found results from 2000 to 6000 RPMs for all three gears. Once the force inverse was found, we plotted the force inverse vs. velocity graph. The area beneath this curve from 0 to 88 feet per second is the time it takes to reach that speed. Using a Riemann sum approximation, we found that the time to be 4.109 seconds. This is a very brief time and is comparable to 5.2 seconds, the time found in a real test by RSPORTSCARS.com.

  4. Vortex-Induced Vibration Tests of a Marine Growth Wrapped Cylinder at Subcritical Reynolds Number

    Directory of Open Access Journals (Sweden)

    Kurian V. J.

    2017-01-01

    Full Text Available Vortex Induced Vibrations (VIV may cause great damage to deep water risers. Estimation of accurate hydrodynamic coefficients and response amplitudes for fouled tubular cylinders subjected to VIVs is a complex task. This paper presents the results of an extensive experimental investigation on in-line and cross-flow forces acting on cylinders wrapped with marine growth, subjected to current at Subcritical Reynolds Number. The drag and lift force coefficients have been determined through the use of the Fast Fourier Analysis methods. The different tests were conducted in the offshore engineering laboratory at Universiti Teknologi PETRONAS (UTP, Malaysia. In this study, a cylinder with outer diameter Do = 27 mm, fixed at top as cantilever beam was used. The in-line and cross-flow forces were measured using VIV Force Totaller (VIVFT. VIVFT is a two degree of freedom (2DOF forces sensor developed by UTP to measure the VIV forces. The tests were conducted for current velocity varied between 0.118 to 0.59 m/s. The test results suggest that the cylinder wrapped with marine growth has shown an overall increase in drag and inertia coefficients as well as on response amplitudes.

  5. EXPLORING THE EFFECTS OF A 20-WEEK WHOLE-BODY VIBRATION TRAINING PROGRAMME ON LEG MUSCLE PERFORMANCE AND FUNCTION IN PERSONS WITH MULTIPLE SCLEROSIS

    OpenAIRE

    BROEKMANS, Tom; Roelants, Machteld; ALDERS, Geert; FEYS, Peter; THIJS, Herbert; OP 'T EIJNDE, Bert

    2010-01-01

    Objective To investigate the acute effects of long term whole body vibration on leg muscle performance and functional capacity in persons with multiple sclerosis Design A randomized controlled trial Subjects Twenty five patients with multiple sclerosis (mean age 47 9 +/- 1 9 years Expanded Disability Status Scale 4 3 +/- 0 2) were assigned randomly to whole body vibration training (n = 11) or to a control group (n = 14) Methods The whole body vibration group performed static and dynamic leg s...

  6. Long-range vibration sensor based on correlation analysis of optical frequency-domain reflectometry signals.

    Science.gov (United States)

    Ding, Zhenyang; Yao, X Steve; Liu, Tiegen; Du, Yang; Liu, Kun; Han, Qun; Meng, Zhuo; Chen, Hongxin

    2012-12-17

    We present a novel method to achieve a space-resolved long- range vibration detection system based on the correlation analysis of the optical frequency-domain reflectometry (OFDR) signals. By performing two separate measurements of the vibrated and non-vibrated states on a test fiber, the vibration frequency and position of a vibration event can be obtained by analyzing the cross-correlation between beat signals of the vibrated and non-vibrated states in a spatial domain, where the beat signals are generated from interferences between local Rayleigh backscattering signals of the test fiber and local light oscillator. Using the proposed technique, we constructed a standard single-mode fiber based vibration sensor that can have a dynamic range of 12 km and a measurable vibration frequency up to 2 kHz with a spatial resolution of 5 m. Moreover, preliminarily investigation results of two vibration events located at different positions along the test fiber are also reported.

  7. Test-retest reliability of muscle vibration effects on postural sway

    NARCIS (Netherlands)

    Kiers, H.; Brumagne, S.; van Dieen, J.H.; Vanhees, L.

    2014-01-01

    The effect of alterations in the processing of proprioceptive signals, on postural control, has been studied using muscle vibration effects. However, reliability and agreement of muscle vibration have still to be addressed.This study aimed to assess intra- and interday reliability and agreement of

  8. Performance and Safety Tests on Samsung 18650 Li-ion Cells: Two Cell Designs

    Science.gov (United States)

    Deng, Yi; Jeevarajan, Judith; Rehm, Raymond; Bragg, Bobby; Zhang, Wenlin

    2002-01-01

    In order to meet the applications for space shuttle in future, two types of Samsung cells, with capacity 1800 mAh and 2000 mAh, have been investigated. The studies focused on: (1) Performance tests: completed 250 cycles at various combinations of charge/discharge C rates and discharge capacity measurements at various temperatures; and (2) Safety tests: overcharge and overdischarge, heat abuse, short circuit, internal and external short, and vibration, vacuum, and drop tests

  9. Astronaut Scott Carpenter tests balance mechanism performance

    Science.gov (United States)

    1961-01-01

    Astronaut M. Scott Carpenter's balance mechanism performance is tested by his walking on a narrow board in his bare feet. He is performing this test at the School of Aviation Medicine, Pensicola, Florida (04570); Carpenter walks a straight line by putting one foot directly in front of the other to test his balance (04571).

  10. Effects of vibration on occupant driving performance under simulated driving conditions.

    Science.gov (United States)

    Azizan, Amzar; Fard, M; Azari, Michael F; Jazar, Reza

    2017-04-01

    Although much research has been devoted to the characterization of the effects of whole-body vibration on seated occupants' comfort, drowsiness induced by vibration has received less attention to date. There are also little validated measurement methods available to quantify whole body vibration-induced drowsiness. Here, the effects of vibration on drowsiness were investigated. Twenty male volunteers were recruited for this experiment. Drowsiness was measured in a driving simulator, before and after 30-min exposure to vibration. Gaussian random vibration, with 1-15 Hz frequency bandwidth was used for excitation. During the driving session, volunteers were required to obey the speed limit of 100 kph and maintain a steady position on the left-hand lane. A deviation in lane position, steering angle variability, and speed deviation were recorded and analysed. Alternatively, volunteers rated their subjective drowsiness by Karolinska Sleepiness Scale (KSS) scores every 5-min. Following 30-min of exposure to vibration, a significant increase of lane deviation, steering angle variability, and KSS scores were observed in all volunteers suggesting the adverse effects of vibration on human alertness level. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. 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

    2017-08-01

    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.

  12. Enhancement of Energy Harvesting Performance by a Coupled Bluff Splitter Body and PVEH Plate through Vortex Induced Vibration near Resonance

    Directory of Open Access Journals (Sweden)

    Wei Ken Chin

    2017-09-01

    Full Text Available Inspired by vortex induced vibration energy harvesting development as a new source of renewable energy, a T-shaped design vibration energy harvester is introduced with the aim of enhancing its performance through vortex induced vibration at near resonance conditions. The T-shaped structural model designed consists of a fixed boundary aluminum bluff splitter body coupled with a cantilever piezoelectric vibration energy harvesters (PVEH plate model which is a piezoelectric bimorph plate made of a brass plate sandwiched between 2 lead zirconate titanate (PZT plates. A 3-dimensional Fluid-Structure Interaction simulation analysis is carried out with Reynolds Stress Turbulence Model under wind speed of 7, 10, 12, 14, 16, 18, 19, 20, 22.5, and 25 m/s. The results showed that with 19 m/s wind speed, the model generates 75.758 Hz of vortex frequency near to the structural model’s natural frequency of 76.9 Hz. Resonance lock-in therefore occurred, generating a maximum displacement amplitude of 2.09 mm or a 49.76% increment relatively in vibrational amplitude. Under the effect of resonance at the PVEH plate’s fundamental natural frequency, it is able to generate the largest normalized power of 13.44 mW/cm3g2.

  13. Small and inconsistent effects of whole body vibration on athletic performance: a systematic review and meta-analysis.

    Science.gov (United States)

    Hortobágyi, Tibor; Lesinski, Melanie; Fernandez-Del-Olmo, Miguel; Granacher, Urs

    2015-08-01

    We quantified the acute and chronic effects of whole body vibration on athletic performance or its proxy measures in competitive and/or elite athletes. Systematic literature review and meta-analysis. Whole body vibration combined with exercise had an overall 0.3 % acute effect on maximal voluntary leg force (-6.4 %, effect size = -0.43, 1 study), leg power (4.7 %, weighted mean effect size = 0.30, 6 studies), flexibility (4.6 %, effect size = -0.12 to 0.22, 2 studies), and athletic performance (-1.9 %, weighted mean effect size = 0.26, 6 studies) in 191 (103 male, 88 female) athletes representing eight sports (overall effect size = 0.28). Whole body vibration combined with exercise had an overall 10.2 % chronic effect on maximal voluntary leg force (14.6 %, weighted mean effect size = 0.44, 5 studies), leg power (10.7 %, weighted mean effect size = 0.42, 9 studies), flexibility (16.5 %, effect size = 0.57 to 0.61, 2 studies), and athletic performance (-1.2 %, weighted mean effect size = 0.45, 5 studies) in 437 (169 male, 268 female) athletes (overall effect size = 0.44). Whole body vibration has small and inconsistent acute and chronic effects on athletic performance in competitive and/or elite athletes. These findings lead to the hypothesis that neuromuscular adaptive processes following whole body vibration are not specific enough to enhance athletic performance. Thus, other types of exercise programs (e.g., resistance training) are recommended if the goal is to improve athletic performance.

  14. Integrated Performance Testing Workshop, Modules 6 - 11

    Energy Technology Data Exchange (ETDEWEB)

    Leach, Janice; Torres, Teresa M.

    2012-10-01

    These modules cover performance testing of: Interior Detection Systems; Access Controls; Exterior Detection Systems; Video Assessment Systems; SNM / Contraband Detection Systems; Access Delay Elements

  15. Whole-body vibration applied during upper body exercise improves performance.

    Science.gov (United States)

    Marín, Pedro J; Herrero, Azael J; Milton, John G; Hazell, Tom J; García-López, David

    2013-07-01

    Whole-body vibration (WBV) training has exercisers perform static and dynamic resistance training exercises on a ground-based platform. Exposure to WBV exposure has demonstrated benefits and no effect on lower body strength, power, and performance. The aim of this study was to determine if WBV exposure (50 Hz, 2.51 mm) has any potentiating effects postexercise by measuring the kinematic variables of a set of upper body elbow-extensor exercise (70% one-repetition maximum [1RM]) to volitional exhaustion. Sixteen recreationally active students (12 male and 4 female) performed 3 different experimental conditions on separate days. Each condition had the subjects perform 1 set of elbow-extension exercise to fatigue with 1 of 3 WBV treatments: WBV simultaneously during the set (AE); 60 seconds after application of WBV for 30 seconds (RE); and no WBV (CTRL). Kinematic parameters of each repetition were monitored by linking a rotary encoder to the highest load plate. The mean velocity and acceleration throughout the set and perceived exertion were analyzed. A significant increase (p < 0.05) was observed in the mean velocity for the whole set in the AE condition vs. the CTRL condition. The mean acceleration was significantly higher (p < 0.05) in the AE condition in comparison with RE (increased by 45.3%) and CTRL (increased by 50.4%) conditions. The positive effect induced by WBV on upper-limb performance is only achieved when the stimulus is applied during the exercise. However, WBV applied 60 seconds before upper body exercise results in no benefit.

  16. Harvesting microalgal biomass using a magnetically induced membrane vibration (MMV) system: filtration performance and energy consumption.

    Science.gov (United States)

    Bilad, M R; Discart, V; Vandamme, D; Foubert, I; Muylaert, K; Vankelecom, Ivo F J

    2013-06-01

    This study was performed to investigate the effectiveness of submerged microfiltration to harvest both a marine diatom Phaeodactylum tricornutum and a Chlorella vulgaris in a recently developed magnetically induced membrane vibrating (MMV) system. We assess the filtration performance by conducting the improved flux step method (IFM), fed-batch concentration filtrations and membrane fouling autopsy using two lab-made membranes with different porosity. The full-scale energy consumption was also estimated. Overall results suggest that the MMV offers a good fouling control and the process was proven to be economically attractive. By combining the membrane filtration (15× concentration) with centrifugation to reach a final concentration of 25% w/v, the energy consumption to harvest P. tricornutum and C. vulgaris was, respectively, as low as 0.84 and 0.77kWh/m(3), corresponding to 1.46 and 1.39 kWh/kg of the harvested biomass. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Numerical methods for acquisition and analysis of vibration tests; Methodes numeriques d'acquisition et de depouillement d'essais aux vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Badel, D.; Cocchi, G.; Oules, H. [Centre d' Etudes Scientifiques et Techniques d' Aquitaine (France). Centre d' Etudes Nucleaires

    1969-07-01

    The S.I.D.E.X. is a digital computer assisted facility for Data acquisition and Data processing. It is designed for sine wave or random environment tests, mechanical or acoustical vibrations, shock waves. The mathematical principles and the system configuration have been described in the CEA file nb R-3666. The present one describes the numerical methods and the programs available up to now. Some examples of results obtained are shown at the end. (authors) [French] Le systeme integre de depouillement pour l'experimentation S.I.D.E.X., a pour but d'effectuer les calibration, les acquisitions et les depouillements des essais aux vibrations sinusoidales ou aleatoires, mecaniques ou acoustiques et des essais de chocs. Les methodes mathematiques correspondantes et la configuration digitale employee ont ete decrites dans le rapport CEA nb CEA-R-3666. Le present rapport indique les methodes numeriques en vigueur et les programmes actuellement disponibles. Des exemples de resultats obtenus sont egalement presentes. (auteurs)

  18. Clinical evaluation of hand-arm-vibration syndrome in shipyard workers: sensitivity and specificity as compared to Stockholm classification and vibrometry testing.

    Science.gov (United States)

    Kent, D C; Allen, R; Bureau, P; Cherniack, M; Hans, J; Robinson, M

    1998-02-01

    The hand-arm-vibration syndrome (HAVS) is a complex entity composed of circulatory, sensory, and motor disturbances, as well as associated musculoskeletal components. This study was performed to find a diagnostic testing modality with sufficient sensitivity, specificity, and predictive value to be utilized as a screening test for this disorder in a working population. A full range of testing modalities was utilized in the shipyard medical department. In addition, a clinical diagnosis of vascular and sensorineural disease was established in the workers by a combination of plethysmography, vibrometry, two point discrimination, and monofilament testing in an independent occupational medicine clinic. No one test modality met the requirements for such a definitive diagnostic test. Rather, a range of modalities was required to reach any acceptable level of predictive value, with sufficient degrees of specificity and sensitivity.

  19. Actuator design for vibration assisted machining of high performance materials with ultrasonically modulated cutting speed

    Science.gov (United States)

    Rinck, Philipp M.; Sitzberger, Sebastian; Zaeh, Michael F.

    2017-06-01

    In vibration assisted machining, an additional high-frequency oscillation is superimposed on the kinematics of the conventional machining process. This generates oscillations on the cutting edge in the range of a few micrometers, thereby causing a high-frequency change in the cutting speed or the feed. Consequently, a reduction of cutting forces, an increase of the tool life as well as an improvement of the workpiece quality can be achieved. In milling and grinding it has been shown that these effects are already partially present in the case of a vibration excitation in axial direction relative to the workpiece, which is perpendicular to the cutting direction. Further improvements of the process results can be achieved by superimposing a vibration in cutting direction and thus modifying the cutting speed at high frequency. The presented work shows the design of an ultrasonic actuator that enables vibration-assisted milling and grinding with ultrasonically modulated cutting speed. The actuator system superimposes a longitudinal torsional ultrasonic oscillation to the milling or grinding tool. It uses a bolt clamped Langevin transducer and a helically slotted horn, which degenerates the longitudinal vibration into a combined longitudinal torsional (L-T) vibration at the output surface. A finite element analysis is used to determine the vibration resonance frequency and mode shapes to maximize the torsional output. Afterwards, the simulation has been experimentally validated.

  20. Integrated Vehicle Ground Vibration Testing in Support of Launch Vehicle Loads and Controls Analysis

    Science.gov (United States)

    Tuma, Margaret L.; Chenevert, Donald J.

    2009-01-01

    NASA has conducted dynamic tests on each major launch vehicle during the past 45 years. Each test provided invaluable data to correlate and correct analytical models. GVTs result in hardware changes to Saturn and Space Shuttle, ensuring crew and vehicle safety. Ares I IVGT will provide test data such as natural frequencies, mode shapes, and damping to support successful Ares I flights. Testing will support controls analysis by providing data to reduce model uncertainty. Value of testing proven by past launch vehicle successes and failures. Performing dynamic testing on Ares vehicles will provide confidence that the launch vehicles will be safe and successful in their missions.

  1. Comparison of analysis and vibration test results for a multiple supported piping system

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, B.J.; Kot, C.A.; Srinivasan, M.G.

    1989-01-01

    The behavior of a nuclear power plant piping system subjected to high level vibrational excitation is investigated experimentally and analytically. The objective is to evaluate the piping analysis method employed in the SMACS computer code. Experimental data are obtained from the Large Shaker Experiments (SHAG) conducted at the HDR Test Facility in Kahl/Main, FRG, in which the dynamic behavior of an in-plant piping system with various support configurations was investigated. Comparisons of calculational results with measured data indicate that the adequacy of the prediction depends primarily on the modeling of boundary conditions and dynamic supports. Treating the latter as rigid and using building motion as input, in general, results in under prediction of piping response. On the other hand when accelerations on the pipe side of the dynamic support attachment are used as input, piping response is highly overpredicted. Also modeling wall/floor component attachments as fixed usually leads to underprediction of amplitude as well as differences in the frequency content of response. 9 refs., 18 figs., 1 tab.

  2. Tire stiffness and damping determined from static and free-vibration tests. [aircraft tires

    Science.gov (United States)

    Sleeper, R. K.; Dreher, R. C.

    1980-01-01

    Stiffness and damping of a nonrolling tire were determined experimentally from both static force-displacement relations and the free-vibration behavior of a cable-suspended platen pressed against the tire periphery. Lateral and force-and-aft spring constants and damping factors of a 49 x 17 size aircraft tire for different tire pressure and vertical loads were measured assuming a rate-independent damping form. In addition, a technique was applied for estimating the magnitude of the tire mass which participates in the vibratory motion of the dynamic tests. Results show that both the lateral and force-and-aft spring constants generally increase with tire pressure but only the latter increased significantly with vertical tire loading. The fore-and-aft spring constants were greater than those in the lateral direction. The static-spring-constant variations were similar to the dynamic variations but exhibited lower magnitudes. Damping was small and insensitive to tire loading. Furthermore, static damping accounted for a significant portion of that found dynamically. Effective tire masses were also small.

  3. 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.

    2016-07-01

    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.

  4. Distributed vibration sensing on optical fibre: field testing in borehole seismic applications

    Science.gov (United States)

    Frignet, B.; Hartog, A. H.; Mackie, D.; Kotov, O. I.; Liokumovich, L. B.

    2014-05-01

    We describe the measurement of seismic waves in a borehole using distributed vibration sensing conveyed on wireline cable. The optical measurement is compared directly with the results of a multi-level borehole seismic survey with conventional electrical accelerometers.

  5. Performance Testing of Download Services of COSMC

    Directory of Open Access Journals (Sweden)

    Jiří Horák

    2013-11-01

    Full Text Available The paper presents results of performance tests of download services of Czech Office of Surveying, Mapping and Cadastre according to INSPIRE  requirements. Methodology of testing is explained, including monitoring performance  of reference servers. 26 millions of random requests were generated for each monitored operation, layer and coordinate system. The temporal development of performance indicators are analyzed and discussed. Results of performance tests approve the compliance with INSPIRE qualitative requirements for download services. All monitored services satisfy requirements of latency, capacity and availability. The latency and availability requirements are fulfilled with an abundant reserve. No problems in structure and content of responses were detected.

  6. Various performance-enhancing effects from the same intensity of whole-body vibration training

    Directory of Open Access Journals (Sweden)

    Paohung Chung

    2017-09-01

    Conclusion: All frequency and amplitude settings in the 8-week whole-body vibration training increased muscle strength, but different settings resulted in various neuromuscular adaptations despite the same intensity.

  7. Finite-Element Vibration Analysis and Modal Testing of Graphite Epoxy Tubes and Correlation Between the Data

    Science.gov (United States)

    Taleghani, Barmac K.; Pappa, Richard S.

    1996-01-01

    Structural materials in the form of graphite epoxy composites with embedded rubber layers are being used to reduce vibrations in rocket motor tubes. Four filament-wound, graphite epoxy tubes were studied to evaluate the effects of the rubber layer on the modal parameters (natural vibration frequencies, damping, and mode shapes). Tube 1 contained six alternating layers of 30-degree helical wraps and 90-degree hoop wraps. Tube 2 was identical to tube 1 with the addition of an embedded 0.030-inch-thick rubber layer. Tubes 3 and 4 were identical to tubes 1 and 2, respectively, with the addition of a Textron Kelpoxy elastomer. This report compares experimental modal parameters obtained by impact testing with analytical modal parameters obtained by NASTRAN finite-element analysis. Four test modes of tube 1 and five test modes of tube 3 correlate highly with corresponding analytical predictions. Unsatisfactory correlation of test and analysis results occurred for tubes 2 and 4 and these comparisons are not shown. Work is underway to improve the analytical models of these tubes. Test results clearly show that the embedded rubber layers significantly increase structural modal damping as well as decrease natural vibration frequencies.

  8. Whole-Body Vibration Training and Its Application to Age-Related Performance Decrements: An Exploratory Analysis.

    Science.gov (United States)

    Hawkey, Adam; Griffiths, Katie; Babraj, John; Cobley, James N

    2016-02-01

    Middle age is associated with a pronounced decline in power and flexibility. Whilst whole-body vibration training (WBVT) improves performance in a range of populations, whether WBVT can improve muscle power and flexibility in a middle-aged population is not known. The present study aimed to determine the influence of 5 weeks progressive WBVT in middle-aged (45-55 years) and younger (20-30 years) recreationally active females. Participants in each age group were randomly allocated to an intervention (WBVT) or control group. The WBVT groups trained for 5 weeks on a vibration platform, while the control groups performed identical exercises, with no vibration. Prior to, and after, the 5-week study vertical countermovement jump (VCMJ) and range of motion (ROM) performance were measured. WBVT significantly (p = 0.001) improved VCMJ performance when compared to the control groups. This improvement was significantly (p = 0.001) greater in the middle-aged compared with the younger WBVT group. WBVT significantly (p = 0.001) improved ROM irrespective of age. Taken together, these results suggest that WBVT can off-set age related performance decrements, which has therapeutic implications for musculoskeletal aging. Therefore, WBVT could be undertaken to minimise age-related performance deterioration in middle-aged female populations.

  9. Diagnostic tests in Raynaud's phenomena in workers exposed to vibration: a comparative study

    DEFF Research Database (Denmark)

    Olsen, N

    1988-01-01

    C, was regarded as an abnormal response, FSP(A) test. A hand cooling, preceded by 30 minute body precooling, was performed in water at 10 degrees C during five minute ischaemia. The finger colours after hand cooling were evaluated by a directly visual inspection, FCV test, and by a blind assessment...

  10. Corrosion performance tests for reinforcing steel in concrete : test procedures.

    Science.gov (United States)

    2009-09-01

    The existing test method to assess the corrosion performance of reinforcing steel embedded in concrete, mainly : ASTM G109, is labor intensive, time consuming, slow to provide comparative results, and often expensive. : However, corrosion of reinforc...

  11. Vibrating vaginal balls to improve pelvic floor muscle performance in women after childbirth: a protocol for a randomised controlled feasibility trial.

    Science.gov (United States)

    Oblasser, Claudia; McCourt, Christine; Hanzal, Engelbert; Christie, Janice

    2016-04-01

    This paper presents a feasibility trial protocol the purpose of which is to prepare for a future randomised controlled trial to determine the effectiveness of vibrating vaginal pelvic floor training balls for postpartum pelvic floor muscle rehabilitation. Vibrating vaginal pelvic floor training balls are available in Austria to enhance women's pelvic floor muscles and thus prevent or treat urinary incontinence and other pelvic floor problems following childbirth. Nonetheless, there is currently little empirical knowledge to substantiate their use or assess their relative effectiveness in comparison to current standard care, which involves pelvic floor muscle exercises. Single blind, randomised controlled feasibility trial with two parallel groups. It is planned to recruit 56 postpartum women in Vienna, who will be randomised into one of two intervention groups to use either vibrating vaginal balls or a comparator pelvic floor muscle exercises for 12 weeks. As this is a feasibility study, study design features (recruitment, selection, randomisation, intervention concordance, data collection methods and tools) will be assessed and participants' views and experiences will be surveyed. Tested outcome measures, collected before and after the intervention, will be pelvic floor muscle performance as reported by participants and measured by perineometry. Descriptive and inferential statistics and content analysis will serve the preparation of the future trial. The results of this feasibility trial will inform the design and conduct of a full randomised controlled trial and provide insight into the experiences of women regarding the interventions and study participation. © 2015 John Wiley & Sons Ltd.

  12. Vitrification Facility integrated system performance testing report

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, D.

    1997-05-01

    This report provides a summary of component and system performance testing associated with the Vitrification Facility (VF) following construction turnover. The VF at the West Valley Demonstration Project (WVDP) was designed to convert stored radioactive waste into a stable glass form for eventual disposal in a federal repository. Following an initial Functional and Checkout Testing of Systems (FACTS) Program and subsequent conversion of test stand equipment into the final VF, a testing program was executed to demonstrate successful performance of the components, subsystems, and systems that make up the vitrification process. Systems were started up and brought on line as construction was completed, until integrated system operation could be demonstrated to produce borosilicate glass using nonradioactive waste simulant. Integrated system testing and operation culminated with a successful Operational Readiness Review (ORR) and Department of Energy (DOE) approval to initiate vitrification of high-level waste (HLW) on June 19, 1996. Performance and integrated operational test runs conducted during the test program provided a means for critical examination, observation, and evaluation of the vitrification system. Test data taken for each Test Instruction Procedure (TIP) was used to evaluate component performance against system design and acceptance criteria, while test observations were used to correct, modify, or improve system operation. This process was critical in establishing operating conditions for the entire vitrification process.

  13. Development of Out-pile Test Technology for Fuel Assembly Performance Verification

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Tae Hyun; In, W. K.; Oh, D. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)] (and others)

    2007-03-15

    Out-pile tests with full scale fuel assembly are to verify the design and to evaluate the performance of the final products. HTL for the hydraulic tests and FAMeCT for mechanical/structural tests were constructed in this project. The maximum operating conditions of HTL are 30 bar, 320 .deg. C, and 500 m3/hr. This facility can perform the pressure drop test, fuel assembly uplift test, and flow induced vibration test. FAMeCT can perform the bending and vibration tests. The verification of the developed facilities were carried out by comparing the reference data of the fuel assembly which was obtained at the Westinghouse Co. The compared data showed a good coincidence within uncertainties. FRETONUS was developed for high temperature and high pressure fretting wear simulator and performance test. A performance test was conducted for 500 hours to check the integrity, endurance, data acquisition capability of the simulator. The technology of turbulent flow analysis and finite element analysis by computation was developed. From the establishments of out-pile test facilities for full scale fuel assembly, the domestic infrastructure for PWR fuel development has been greatly upgraded.

  14. SI PC104 Performance Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Montelongo, S

    2005-12-16

    The Spectral Instruments (SI) PC104 systems associated with the SI-1000 CCD camera exhibited intermittent power problems during setup, test and operations which called for further evaluation and testing. The SI PC104 System is the interface between the SI-1000 CCD camera and its associated Diagnostic Controller (DC). As such, the SI PC104 must be a reliable, robust system capable of providing consistent performance in various configurations and operating conditions. This SI PC104 system consists of a stackable set of modules designed to meet the PC104+ Industry Standard. The SI PC104 System consists of a CPU module, SI Camera card, Media converter card, Video card and a I/O module. The root cause of power problems was identified as failing solder joints at the LEMO power connector attached to the SI Camera Card. The recommended solution was to provide power to the PC104 system via a PC104+ power supply module configured into the PC104 stack instead of thru the LEMO power connector. Test plans (2) were developed to test SI PC104 performance and identify any outstanding issues noted during extended operations. Test Plan 1 included performance and image acquisition tests. Test Plan 2 verified performance after implementing recommendations. Test Plan 2 also included verifying integrity of system files and driver installation after bootup. Each test plan was implemented to fully test against each set of problems noted. Test Plan presentations and Test Plan results are attached as appendices. Anticipated test results will show successful operation and reliable performance of the SI PC104 system receiving its power via a PC104 power supply module. A SI PC104 Usage Recommendation Memo will be sent out to the SI PC104 User Community. Recommendation memo(s) are attached as appendices.

  15. Performance Characteristics of Vibration-Controlled Transient Elastography for Evaluation of Non-Alcoholic Fatty Liver Disease.

    Science.gov (United States)

    Vuppalanchi, Raj; Siddiqui, Mohammad S; Van Natta, Mark L; Hallinan, Erin; Brandman, Danielle; Kowdley, Kris; Neuschwander-Tetri, Brent A; Loomba, Rohit; Dasarathy, Srinivas; Abdelmalek, Manal; Doo, Edward; Tonascia, James A; Kleiner, David E; Sanyal, Arun J; Chalasani, Naga

    2017-08-31

    Vibration-controlled transient elastography (VCTE) estimates liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) which are noninvasive assessments of hepatic fibrosis and steatosis respectively. However, prior VCTE studies reported high failure rate in patients with non-alcoholic fatty liver disease (NAFLD). To examine the performance characteristics of Fibroscan 502 Touch with two probes, medium (M+) and extra-large (XL+), in patients with NAFLD in a multicenter setting. A total of 1696 exams were attempted in 992 patients (BMI: 33.6 ± 6.5 kg/m(2) ) with histologically confirmed NAFLD. Simultaneous assessment of LSM and CAP was performed using Fibroscan 502 Touch with an automatic probe selection tool. Testing was conducted twice in patients by either a single operator (88%) or two operators (12%). Failure was defined as the inability to obtain a valid examination. An examination was considered unreliable if LSM IQR/median was >30%. Significant disagreement between two readings was defined as greater than >95% limits of agreement between two readings. A total of 1641 examinations yielded valid results with a failure rate of 3.2% (55/1696). The proportion of unreliable scans for LSM was 2.4%. The proportion of unreliable scans with operator experience in the top quartile (≥ 59 procedures) was significantly lower than lower three quarters combined (1.6% vs.4.7%, p=0.01 by Fisher's Exact test). The significant disagreement between first and second readings for LSM and CAP when obtained back to back was 18% and 11% respectively. VCTE for estimation of LSM and CAP can be successfully deployed in a multicenter setting with low failure (3.2%) and high reliability (>95%) rates and high reproducibility. This article is protected by copyright. All rights reserved. © 2017 by the American Association for the Study of Liver Diseases.

  16. Agility in Team Sports: Testing, Training and Factors Affecting Performance.

    Science.gov (United States)

    Paul, Darren J; Gabbett, Tim J; Nassis, George P

    2016-03-01

    Agility is an important characteristic of team sports athletes. There is a growing interest in the factors that influence agility performance as well as appropriate testing protocols and training strategies to assess and improve this quality. The objective of this systematic review was to (1) evaluate the reliability and validity of agility tests in team sports, (2) detail factors that may influence agility performance, and (3) identify the effects of different interventions on agility performance. The review was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We conducted a search of PubMed, Google Scholar, Science Direct, and SPORTDiscus databases. We assessed the methodological quality of intervention studies using a customized checklist of assessment criteria. Intraclass correlation coefficient values were 0.80-0.91, 0.10-0.81, and 0.81-0.99 for test time using light, video, and human stimuli. A low-level reliability was reported for youth athletes using the video stimulus (0.10-0.30). Higher-level participants were shown to be, on average, 7.5% faster than their lower level counterparts. Reaction time and accuracy, foot placement, and in-line lunge movement have been shown to be related to agility performance. The contribution of strength remains unclear. Efficacy of interventions on agility performance ranged from 1% (vibration training) to 7.5% (small-sided games training). Agility tests generally offer good reliability, although this may be compromised in younger participants responding to various scenarios. A human and/or video stimulus seems the most appropriate method to discriminate between standard of playing ability. Decision-making and perceptual factors are often propositioned as discriminant factors; however, the underlying mechanisms are relatively unknown. Research has focused predominantly on the physical element of agility. Small-sided games and video training may offer effective

  17. Effects of Test Anxiety, Tests, and Sleep on Children's Performance.

    Science.gov (United States)

    Horn, Jennifer L.; Dollinger, Stephen J.

    1989-01-01

    Sixth and seventh graders (N=239) responded to questionnaires examining sleep behavior and test anxiety on day of major examination in school and day with no major examination. Subjects also completed vigilance task on both days. Partial sleep loss did not adversely influence subjects' performance on task or examination; test anxiety was…

  18. The relationship between standardised test performance and ...

    African Journals Online (AJOL)

    ... of compensation, metacognitive, affective and social strategies. The implications for language teaching in Curriculum 2005 context are briefly indicated. Key words: standardised test performance, language learning strategies, English Second Language, KwaZulu-Natal, underachievement, secondary school, case study

  19. Integrated Performance Testing for Nonproliferation Support Project

    Energy Technology Data Exchange (ETDEWEB)

    Johns, Russell; Bultz, Garl Alan; Byers, Kenneth R.; Yaegle, William

    2013-08-20

    The objective of this workshop is to provide participants with training in testing techniques and methodologies for assessment of the performance of: Physical Protection system elements; Material Control and Accounting (MC&A) system elements.

  20. PNGV Battery Performance Testing and Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Motloch, Chester George; Belt, Jeffrey R; Christophersen, Jon Petter; Wright, Randy Ben; Hunt, Gary Lynn; Sutula, Raymond; Duong, T.Q.; Barnes, J.A.; Miller, Ted J.; Haskind, H. J.; Tartamella, T. J.

    2002-03-01

    In support of the Partnership for a New Generation of Vehicles (PNGV), the Idaho National Engineering and Environmental Laboratory (INEEL) has developed novel testing procedures and analytical methodologies to assess the performance of batteries for use in hybrid electric vehicles (HEV’s). Tests have been designed for both Power Assist and Dual Mode applications. They include both characterization and cycle life and/or calendar life. At periodic intervals during life testing, a series of Reference Performance Tests are executed to determine changes in the baseline performance of the batteries. Analytical procedures include a battery scaling methodology, the calculation of pulse resistance, pulse power, available energy, and differential capacity, and the modeling of calendar- and cycle-life data. PNGV goals, test procedures, analytical methodologies, and representative results are presented.

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

    Science.gov (United States)

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

    2017-01-01

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

  2. The relationship between standardised test performance and ...

    African Journals Online (AJOL)

    Data gathering took place by means of the application of two standardised tests, the Writing Performance Test in English and the Strategy Inventory for Language Learning, an individual interview using a structured interview schedule and observation in the teaching and learning environment. It was found that a significant ...

  3. Design and performance test of spacecraft test and operation software

    Science.gov (United States)

    Wang, Guohua; Cui, Yan; Wang, Shuo; Meng, Xiaofeng

    2011-06-01

    Main test processor (MTP) software is the key element of Electrical Ground Support Equipment (EGSE) for spacecraft test and operation used in the Chinese Academy of Space Technology (CAST) for years without innovation. With the increasing demand for a more efficient and agile MTP software, the new MTP software was developed. It adopts layered and plug-in based software architecture, whose core runtime server provides message queue management, share memory management and process management services and forms the framework for a configurable and open architecture system. To investigate the MTP software's performance, the test case of network response time, test sequence management capability and data-processing capability was introduced in detail. Test results show that the MTP software is common and has higher performance than the legacy one.

  4. 47 CFR 76.601 - Performance tests.

    Science.gov (United States)

    2010-10-01

    ... network: Provided, that data shall be included to relate the measured performance of the system as would be viewed from a nearby subscriber terminal. An identification of the instruments, including the..., and a statement of the qualifications of the person performing the tests shall also be included. (2...

  5. Work zone performance measures pilot test.

    Science.gov (United States)

    2011-04-01

    Currently, a well-defined and validated set of metrics to use in monitoring work zone performance do not : exist. This pilot test was conducted to assist state DOTs in identifying what work zone performance : measures can and should be targeted, what...

  6. Cognitive test performance and background music.

    Science.gov (United States)

    Cockerton, T; Moore, S; Norman, D

    1997-12-01

    This study examined the effects of background music on test performance. In a repeated-measures design 30 undergraduates completed two cognitive tests, one in silence and the other with background music. Analysis suggested that music facilitated cognitive performance compared with the control condition of no music: more questions were completed and more answers were correct. There was no difference in heart rate under the two conditions. The improved performance under the music condition might be directly related to the type of music used.

  7. Design and Execution of a Test Rig for Studying the Vibrations of a Gearbox

    Directory of Open Access Journals (Sweden)

    Zoltan Korka

    2008-10-01

    Full Text Available The current trend in the construction of gearboxes, regarding the speed increase, favours the increase of the dynamic loads which are accompanying the operation of these kinds of machines. The phenomena of dynamic contact like frictions, collisions and shocks which are taking place in cinematic couples, engines and mechanisms during their movement, are generating vibrations in a wide range of frequencies.

  8. Performance Test for the SIGMA Communication System

    Science.gov (United States)

    Jeong, Seonyeong; Lee, Hyojeong; Lee, Seongwhan; Shin, Jehyuck; Lee, Jungkyu; Jin, Ho

    2016-12-01

    Scientific CubeSat with Instruments for Global Magnetic Fields and Radiations (SIGMA) is a 3-U size CubeSat that will be operated in low earth orbit (LEO). The SIGMA communication system uses a very high frequency (VHF) band for uplink and an ultra high frequency (UHF) band for downlink. Both frequencies belong to an amateur band. The ground station that communicates with SIGMA is located at Kyung Hee Astronomical Observatory (KHAO). For reliable communication, we carried out a laboratory (LAB) test and far-field tests between the CubeSat and a ground station. In the field test, we considered test parameters such as attenuation, antenna deployment, CubeSat body attitude, and Doppler frequency shift in transmitting commands and receiving data. In this paper, we present a communication performance test of SIGMA, a link budget analysis, and a field test process. We also compare the link budget with the field test results of transmitting commands and receiving data.

  9. Multicenter Performance Assessment of Carba NP Test.

    Science.gov (United States)

    Cunningham, Scott A; Limbago, Brandi; Traczewski, Maria; Anderson, Karen; Hackel, Meredith; Hindler, Janet; Sahm, Dan; Alyanak, Efe; Lawsin, Adrian; Gulvik, Christopher A; de Man, Tom J B; Mandrekar, Jayawant N; Schuetz, Audrey N; Jenkins, Stephen; Humphries, Romney; Palavecino, Elizabeth; Vasoo, Shawn; Patel, Robin

    2017-06-01

    Eighty Gram-negative bacilli (54 Enterobacteriaceae and 26 nonfermenting Gram-negative bacilli) obtained from multiple institutions in the United States were distributed in a blinded manner to seven testing laboratories to compare their performance of a test for detection of carbapenemase production, the Carba NP test. The Carba NP test was performed by all laboratories, following the Clinical and Laboratory Standards Institute (CLSI) procedure. Site-versus-site comparisons demonstrated a high level of consistency for the Carba NP assay, with just 3/21 site comparisons yielding a difference in sensitivity (P NP test, when implemented with the standardized CLSI methodology, provides reproducible results across multiple sites for detection of carbapenemases. Copyright © 2017 American Society for Microbiology.

  10. Performance of improved magnetostrictive vibrational power generator, simple and high power output for practical applications

    Science.gov (United States)

    Ueno, Toshiyuki

    2015-05-01

    Vibration based power generation technology is utilized effectively in various fields. Author has invented novel vibrational power generation device using magnetostrictive material. The device is based on parallel beam structure consisting of a rod of iron-gallium alloy wound with coil and yoke accompanied with permanent magnet. When bending force is applied on the tip of the device, the magnetization inside the rod varies with induced stress due to the inverse magnetostrictive effect. In vibration, the time variation of the magnetization generates voltage on the wound coil. The magnetostrictive type is advantageous over conventional such using piezoelectric or moving magnet types in high efficiency and high robustness, and low electrical impedance. Here, author has established device configuration, simple, rigid, and high power output endurable for practical applications. In addition, the improved device is lower cost using less volume of Fe-Ga and permanent magnet compared to our conventional, and its assembly by soldering is easy and fast suitable for mass production. Average power of 3 mW/cm3 under resonant vibration of 212 Hz and 1.2 G was obtained in miniature prototype using Fe-Ga rod of 2 × 0.5× 7 mm3. Furthermore, the damping effect was observed, which demonstrates high energy conversion of the generator.

  11. An Intelligent Optimization Method for Vortex-Induced Vibration Reducing and Performance Improving in a Large Francis Turbine

    Directory of Open Access Journals (Sweden)

    Xuanlin Peng

    2017-11-01

    Full Text Available In this paper, a new methodology is proposed to reduce the vortex-induced vibration (VIV and improve the performance of the stay vane in a 200-MW Francis turbine. The process can be divided into two parts. Firstly, a diagnosis method for stay vane vibration based on field experiments and a finite element method (FEM is presented. It is found that the resonance between the Kármán vortex and the stay vane is the main cause for the undesired vibration. Then, we focus on establishing an intelligent optimization model of the stay vane’s trailing edge profile. To this end, an approach combining factorial experiments, extreme learning machine (ELM and particle swarm optimization (PSO is implemented. Three kinds of improved profiles of the stay vane are proposed and compared. Finally, the profile with a Donaldson trailing edge is adopted as the best solution for the stay vane, and verifications such as computational fluid dynamics (CFD simulations, structural analysis and fatigue analysis are performed to validate the optimized geometry.

  12. Investigation of the performances of PZT vs rare earth (BaLaTiO3 vibration based energy harvester

    Directory of Open Access Journals (Sweden)

    Pak Nehemiah

    2017-01-01

    Full Text Available This study proposes the investigation of two piezoelectric material namely PZT and Lanthanum Doped Barium Titanate (BaLaTiO3 performance as a vibration based energy harvester. The piezoelectric material when applied mechanical stress or strain produces electricity through the piezoelectric effect. The vibration energy would exude mechanical energy and thus apply mechanical force on the energy harvester. The energy harvester would be designed and simulated using the piezoelectric material individually. The studied outputs are divided to frequency response, the load dependence, and the acceleration dependence whereby measurement are observed and taken at maximum power output. The simulation is done using the cantilevers design which employs d31 type of constants. Three different simulations to study the dependence of output power on the resonant frequency response, load and acceleration have found that material that exhibit highest power generation was the BaLaTiO3.

  13. The Shock and Vibration Bulletin. Part 2. Model Test and Analysis, Testing Techniques, Machinery Dynamics, Isolation and Damping, Structural Dynamics

    Science.gov (United States)

    1986-08-01

    jBfr 5? JOR JS T SIONAL/lBRATIONjerF^EAR-RANCHED PROPULSION.gVSTEMS j... 117 / H.F. Tavares, Cepstrum Engenharia Ltda., Rio de Janeiro, Brazil and V...MODELLING IN FINITE ELEMENT ANALYSES OF TORSIONAL VIBRATION OF GEAR-BRANCHED PROPULSION SYSTEMS H. F. Tavares Cepstrum Engenharia Ltda. S8o Paulo

  14. A 5-week whole body vibration training improves peak torque performance but has no effect on stretch reflex in healthy adults: a randomized controlled trial.

    Science.gov (United States)

    Yeung, S S; Yeung, E W

    2015-05-01

    This study aimed to investigate the neuromuscular adaptation following a 5-week high frequency and low amplitude whole body vibration (WBV) exercise training. The study is a prospective, double blind, randomized controlled intervention design with a total of 19 subjects volunteered to participate in the study. They were randomly assigned either to WBV exercise training or control group. Both groups participated in a 5-week training program. The intervention group received WBV in semi-squat position on a device with an amplitude of 0.76 mm, frequency of 40Hz, and peak acceleration of 23.9 m/s2. Each vibration training session consisted of 6 series of 60s on with 30s rest period in between. The control group underwent the same statically mini-squatting position without exposure to WBV. The effectiveness of the vibration program was evaluated by vertical jump test and the isokinetic knee extensor peak torque. The possible neural factors that contributed to the improved muscular performance were evaluated by the stretch induced knee jerk reflex. WBV training significantly enhanced the isokinetic knee extensor peak torque performance. Two-way mixed repeated measures analysis of variance revealed significant time effect of the changes in the peak torque (P=0.043) and the effect was significantly different between the intervention and control group (P=0.042). WBV did not affect vertical jump height, reflex latency of VL, EMGVL, and knee jerk angle. The results of this study do not support the hypothesis that the improvement in the muscular performance when subjects exposed to WBV training is attributed by neuromuscular efficiency via modulation of the muscle spindle sensitivity.

  15. An on-road shock and vibration response test series utilizing worst case and statistical analysis techniques

    Energy Technology Data Exchange (ETDEWEB)

    Cap, J.S. [Sandia National Labs., Albuquerque, NM (US). Mechanical and Thermal Environments Dept.

    1997-11-01

    Defining the maximum expected shock and vibration responses for an on-road truck transportation environment is strongly dependent on the amount of response data that can be obtained. One common test scheme consists of measuring response data over a relatively short prescribed road course and then reviewing that data to obtain the maximum response levels. The more mathematically rigorous alternative is to collect an unbiased ensemble of response data during a long road trip. This paper compares data gathered both ways during a recent on-road certification test for a tractor trailer van being designed by Sandia.

  16. Thermal Performance Testing of Cryogenic Insulation Systems

    Science.gov (United States)

    Fesmire, James E.; Augustynowicz, Stan D.; Scholtens, Brekke E.

    2007-01-01

    Efficient methods for characterizing thermal performance of materials under cryogenic and vacuum conditions have been developed. These methods provide thermal conductivity data on materials under actual-use conditions and are complementary to established methods. The actual-use environment of full temperature difference in combination with vacuum-pressure is essential for understanding insulation system performance. Test articles include solids, foams, powders, layered blankets, composite panels, and other materials. Test methodology and apparatus design for several insulation test cryostats are discussed. The measurement principle is liquid nitrogen boil-off calorimetry. Heat flux capability ranges from approximately 0.5 to 500 watts per square meter; corresponding apparent thermal conductivity values range from below 0.01 up to about 60 mW/m- K. Example data for different insulation materials are also presented. Upon further standardization work, these patented insulation test cryostats can be available to industry for a wide range of practical applications.

  17. GOES-R Active Vibration Damping Controller Design, Implementation, and On-Orbit Performance

    Science.gov (United States)

    Clapp, Brian R.; Weigl, Harald J.; Goodzeit, Neil E.; Carter, Delano R.; Rood, Timothy J.

    2017-01-01

    GOES-R series spacecraft feature a number of flexible appendages with modal frequencies below 3.0 Hz which, if excited by spacecraft disturbances, can be sources of undesirable jitter perturbing spacecraft pointing. In order to meet GOES-R pointing stability requirements, the spacecraft flight software implements an Active Vibration Damping (AVD) rate control law which acts in parallel with the nadir point attitude control law. The AVD controller commands spacecraft reaction wheel actuators based upon Inertial Measurement Unit (IMU) inputs to provide additional damping for spacecraft structural modes below 3.0 Hz which vary with solar wing angle. A GOES-R spacecraft dynamics and attitude control system identified model is constructed from pseudo-random reaction wheel torque commands and IMU angular rate response measurements occurring over a single orbit during spacecraft post-deployment activities. The identified Fourier model is computed on the ground, uplinked to the spacecraft flight computer, and the AVD controller filter coefficients are periodically computed on-board from the Fourier model. Consequently, the AVD controller formulation is based not upon pre-launch simulation model estimates but upon on-orbit nadir point attitude control and time-varying spacecraft dynamics. GOES-R high-fidelity time domain simulation results herein demonstrate the accuracy of the AVD identified Fourier model relative to the pre-launch spacecraft dynamics and control truth model. The AVD controller on-board the GOES-16 spacecraft achieves more than a ten-fold increase in structural mode damping of the fundamental solar wing mode while maintaining controller stability margins and ensuring that the nadir point attitude control bandwidth does not fall below 0.02 Hz. On-orbit GOES-16 spacecraft appendage modal frequencies and damping ratios are quantified based upon the AVD system identification, and the increase in modal damping provided by the AVD controller for each structural

  18. WHOLE-BODY VIBRATION TRAINING COMPARED WITH RESISTANCE TRAINING: EFFECT ON SPASTICITY, MUSCLE STRENGTH AND MOTOR PERFORMANCE IN ADULTS WITH CEREBRAL PALSY

    National Research Council Canada - National Science Library

    Ahlborg, Lotta; Andersson, Christina; Julin, Per

    2006-01-01

    Objective: The aim of this study was to evaluate the effect on spasticity, muscle strength and motor performance after 8 weeks of whole-body vibration training compared with resistance training in adults with cerebral palsy. Methods...

  19. Testing prospect theory in students’ performance

    OpenAIRE

    Pérez Galdón, Patricia; Nicolau, Juan Luis

    2013-01-01

    This paper tests the existence of ‘reference dependence’ and ‘loss aversion’ in students’ academic performance. Accordingly, achieving a worse than expected academic performance would have a much stronger effect on students’ (dis)satisfaction than obtaining a better than expected grade. Although loss aversion is a well-established finding, some authors have demonstrated that it can be moderated – diminished, to be precise–. Within this line of research, we also examine whether the students’ e...

  20. Structural Health Monitoring Using Wireless Technologies: An Ambient Vibration Test on the Adolphe Bridge, Luxembourg City

    Directory of Open Access Journals (Sweden)

    Adrien Oth

    2012-01-01

    Full Text Available Major threats to bridges primarily consist of the aging of the structural elements, earthquake-induced shaking and standing waves generated by windstorms. The necessity of information on the state of health of structures in real-time, allowing for timely warnings in the case of damaging events, requires structural health monitoring (SHM systems that allow the risks of these threats to be mitigated. Here we present the results of a short-duration experiment carried out with low-cost wireless instruments for monitoring the vibration characteristics and dynamic properties of a strategic civil infrastructure, the Adolphe Bridge in Luxembourg City. The Adolphe Bridge is a masonry arch construction dating from 1903 and will undergo major renovation works in the upcoming years. Our experiment shows that a network of these wireless sensing units is well suited to monitor the vibration characteristics of such a historical arch bridge and hence represents a low-cost and efficient solution for SHM.

  1. SAS molecular tests Salmonella detection kit. Performance tested method 021202.

    Science.gov (United States)

    Bapanpally, Chandra; Montier, Laura; Khan, Shah; Kasra, Akif; Brunelle, Sharon L

    2014-01-01

    The SAS Molecular tests Salmonella Detection method, a Loop-mediated Isothermal Amplification method, performed as well as or better than the U.S. Department of Agriculture-Food Safety Inspection Service Microbiology Laboratory Guidebook and the U.S. Food and Drug Administration Bacteriological Analytical Manual reference methods for ground beef, beef trim, ground turkey, chicken carcass rinses, bagged mixed lettuce, and fresh spinach. The ground beef (30% fat, 25 g test portion), poultry matrixes and leafy greens were validated in a 6-7 h enrichment, and ground beef (30% fat, 375 g composite test portion) and beef trim (375 g composite test portion) were validated in a 16-20 h enrichment. The method performance for meat and leafy green matrixes was shown to be acceptable under conditions of co-enrichment with Escherichia coli 0157. Thus, after a short 6-7 h co-enrichment step, ground beef, beef trim, lettuce, and spinach can be tested for both Salmonella and E. coli O157. Inclusivity and exclusivity testing revealed no false negatives and no false positives among the 100 Salmonella serovars and 30 non-Salmonella species examined. The method was shown to be robust when enrichment time, DNA extract hold time, and DNA volume were varied.

  2. SRG110 Stirling Generator Dynamic Simulator Vibration Test Results and Analysis Correlation

    Science.gov (United States)

    Lewandowski, Edward J.; Suarez, Vicente J.; Goodnight, Thomas W.; Callahan, John

    2007-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin (LM), and NASA Glenn Research Center (GRC) have been developing the Stirling Radioisotope Generator (SRG110) for use as a power system for space science missions. The launch environment enveloping potential missions results in a random input spectrum that is significantly higher than historical radioisotope power system (RPS) launch levels and is a challenge for designers. Analysis presented in prior work predicted that tailoring the compliance at the generator-spacecraft interface reduced the dynamic response of the system thereby allowing higher launch load input levels and expanding the range of potential generator missions. To confirm analytical predictions, a dynamic simulator representing the generator structure, Stirling convertors and heat sources were designed and built for testing with and without a compliant interface. Finite element analysis was performed to guide the generator simulator and compliant interface design so that test modes and frequencies were representative of the SRG110 generator. This paper presents the dynamic simulator design, the test setup and methodology, test article modes and frequencies and dynamic responses, and post-test analysis results. With the compliant interface, component responses to an input environment exceeding the SRG110 qualification level spectrum were all within design allowables. Post-test analysis included finite element model tuning to match test frequencies and random response analysis using the test input spectrum. Analytical results were in good overall agreement with the test results and confirmed previous predictions that the SRG110 power system may be considered for a broad range of potential missions, including those with demanding launch environments.

  3. Ultrasonic vibration imposed on nanoparticle-based ZnO film improves the performance of the ensuing perovskite solar cell

    Science.gov (United States)

    Miao, Yihe; Du, Peng; Wang, Zhiyu; Chen, Qianli; Eslamian, Morteza

    2018-02-01

    This work focuses on the development of nearly annealing-free ZnO-based perovskite solar cells (PSCs), suitable for low-cost manufacturing of PSCs on flexible substrates. To this end, thin film of ZnO nanoparticles is employed as the electron transporting layer (ETL), because of its low-temperature solution-processability and high electron mobility. In order to remove the structural and surface defects, ultrasonic vibration is imposed on the substrate of the as-spun wet ZnO films for a short duration of 3 min. It is shown that the ultrasonic excitation bridges the ZnO nanoparticles (cold sintering), and brings about significant improvement in the ZnO film nanostructure and functionality. In addition, ethyl acetate (EA), as an emerging volatile anti-solvent, is employed to deposit the methylammonium (MA) lead halide perovskite thin film atop the ZnO ETL, in order to prepare perovskite layers that only need an annealing time of 30 s. The ZnO-based PSCs, with a simple structure and free of additional treatments, except for the ultrasonic vibration, exhibit a promising performance with a power conversion efficiency (PCE) of over 11%, 40% higher than that of the control device. The ultrasonic vibration treatment is facile, low-cost, environmentally friendly, and compatible with the scalable coating and printing techniques, such as spray and blade coating.

  4. Testing for Distortions in Performance Measures

    DEFF Research Database (Denmark)

    Sloof, Randolph; Van Praag, Mirjam

    2015-01-01

    Distorted performance measures in compensation contracts elicit suboptimal behavioral responses that may even prove to be dysfunctional (gaming). This paper applies the empirical test developed by Courty and Marschke (Review of Economics and Statistics, 90, 428-441) to detect whether the widely...... used class of residual income-based performance measures-such as economic value added (EVA)-is distorted, leading to unintended agent behavior. The paper uses a difference-in-differences approach to account for changes in economic circumstances and the self-selection of firms using EVA. Our findings...... indicate that EVA is a distorted performance measure that elicits the gaming response....

  5. Testing for Distortions in Performance Measures

    DEFF Research Database (Denmark)

    Sloof, Randolph; Van Praag, Mirjam

    Distorted performance measures in compensation contracts elicit suboptimal behavioral responses that may even prove to be dysfunctional (gaming). This paper applies the empirical test developed by Courty and Marschke (2008) to detect whether the widely used class of Residual Income based...... performance measures —such as Economic Value Added (EVA)— is distorted, leading to unintended agent behavior. The paper uses a difference-in-differences approach to account for changes in economic circumstances and the self-selection of firms using EVA. Our findings indicate that EVA is a distorted...... performance measure that elicits the gaming response....

  6. Testing predictive performance of binary choice models

    NARCIS (Netherlands)

    A.C.D. Donkers (Bas); B. Melenberg (Bertrand)

    2002-01-01

    textabstractBinary choice models occur frequently in economic modeling. A measure of the predictive performance of binary choice models that is often reported is the hit rate of a model. This paper develops a test for the outperformance of a predictor for binary outcomes over a naive prediction

  7. Assessing cardiorespiratory fitness without performing exercise testing

    NARCIS (Netherlands)

    Jurca, R.; Jackson, A.S.; LaMonte, M.J.; Morrow, J.R.; Blair, S.N.; Wareham, N.J.; Haskell, W.L.; van Mechelen, W.; Church, T.S.; Jakicic, J.M.; Laukkanen, R.

    2005-01-01

    Background: Low cardiorespiratory fitness (CRF) is associated with increased risk of chronic diseases and mortality; however, CRF assessment is usually not performed in many healthcare settings. The purpose of this study is to extend previous work on a non-exercise test model to predict CRF from

  8. NetBench. Automated Network Performance Testing

    CERN Document Server

    Cadeddu, Mattia

    2016-01-01

    In order to evaluate the operation of high performance routers, CERN has developed the NetBench software to run benchmarking tests by injecting various traffic patterns and observing the network devices behaviour in real-time. The tool features a modular design with a Python based console used to inject traffic and collect the results in a database, and a web user

  9. Performance tests for integral reactor nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Dong-Seong; Yim, Jeong-Sik; Lee, Chong-Tak; Kim, Han-Soo; Koo, Yang-Hyun; Lee, Byung-Ho; Cheon, Jin-Sik; Oh, Je-Yong

    2006-02-15

    An integral type reactor SMART plans to utilize metallic Zr-U fuel which is Zr-based alloy with 34{approx}38 wt% U. In order to verify the technologies for the design and manufacturing of the fuel and get a license, performance tests were carried out. Experimental Fuel Assembly (EFA) manufactured in KAERI is being successfully irradiated in the MIR reactor of RIAR from September 4 2004, and it has achieved burnup of 0.21 g/cc as of January 25 2006. Thermal properties of irradiated Zr-U fuel were measured. Up to the phase transformation temperature, thermal diffusivity increased linearly in proportion to temperature. However its dependence on the burnup was not significant. RIA tests with 4 unirradiated Zr-U fuel rods were performed in Kurchatov Institute to establish a safety criterion. In the case of the un-irradiated Zr-U fuel, the energy deposition during the control rod ejection accident should be less than 172 cal/g to prevent the failure accompanying fuel fragmentation and dispersal. Finally the irradiation tests of fuel rods have been performed at HANARO. The HITE-2 test was successfully completed up to a burnup of 0.31 g/cc. The HITE-3 test began in February 2004 and will be continued up to a target burnup of 0.6 g/cc.

  10. Analysis and testing of an integrated semi-active seat suspension for both longitudinal and vertical vibration control

    Science.gov (United States)

    Bai, Xian-Xu; Jiang, Peng; Pan, Hui; Qian, Li-Jun

    2016-04-01

    An integrated semi-active seat suspension for both longitudinal and vertical vibration control is analyzed and tested in this paper. The seat suspension consists of a switching mechanism transforming both longitudinal and vertical motions into a rotary motion and a real-time damping-controllable system-a rotary magnetorheological (MR) damper working in pure shear mode and its corresponding control system. The switching mechanism employs the parallelogram frames as a motion guide which keeps the seat moving longitudinally and vertically. At the same time, both longitudinal and vertical motions are transformed into a reciprocating rotary motion that is transmitted to the rotary MR damper after an amplification by a gear mechanism. Both the longitudinal and vertical vibrations can be attenuated in real time through controlling the damping force (or torque) of the rotary MR damper. The mathematical model of the seat suspension system is established, simulated, and analyzed. The experimental test based on the test rig in Hefei University of Technology is implemented, and the results of simulation and experimental test are compared and analyzed.

  11. Damage monitoring and impact detection using optical fiber vibration sensors

    Science.gov (United States)

    Yang, Y. C.; Han, K. S.

    2002-06-01

    Intensity-based optical fiber vibrations sensors (OFVSs) are used in damage monitoring of fiber-reinforced plastics, in vibration sensing, and location of impacts. OFVSs were constructed by placing two cleaved fiber ends in a capillary tube. This sensor is able to monitor structural vibrations. For vibration sensing, the optical fiber sensor was mounted on the carbon fiber reinforced composite beam, and its response was investigated for free and forced vibration. For locating impact points, four OFVSs were placed at chosen positions and the different arrival times of impact-generated vibration signals were recorded. The impact location can be determined from these time delays. Indentation and tensile tests were performed with the measurement of the optical signal and acoustic emission (AE). The OFVSs accurately detected both free and forced vibration signals. Accurate locations of impact were determined on an acrylate plate. It was found that damage information, comparable in quality to AE data, could be obtained from the OFVS signals.

  12. Identification of dynamic characteristics by field vibration test in Tsurumi Tsubasa bridge; Tsurumi Tsubasakyo no shindo jikken ni yoru doteki tokusei no dotei

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H. [Saitama University, Saitama (Japan). Faculty of Engineering; Takano, H.; Ogasawara, M.; Shimosato, T. [Metropolitan Expressway Public Corp., Tokyo (Japan); Kato, M.; Okada, J. [NKK Corp., Tokyo (Japan)

    1996-07-21

    Field vibration test of the Tsurumi Tsubasa Bridge, a long span cable stayed bridge, has been conducted. Focusing on its dynamic characteristics, an identification method from test results and its validity were investigated. The natural frequency identified using mode circle and resonance curve from steady vibration test agreed with that identified by the peak method from free damping test. Accordingly, there was no difference due to identification methods, and both methods provided appropriate accuracy. The natural vibration mode obtained from the steady vibration test agreed with that obtained by the eigenvalue analysis. The dispersion of experimental values, which indicates the adaptation to mode circle method, became a scale indicating reliability of identified values. When the damping obtained by the half power method for the microtremors test is compared with that identified from the steady vibration test and free damping test, it is required to compare them at lower amplitude level region, considering that the amplitude level of microtremors test is very low. For the dynamic characteristics of the Tsurumi Tsubasa Bridge, it was found that it has lower natural frequency and higher modal damping compared with other cable stayed bridges with similar scale of span. 18 refs., 13 figs., 4 tabs.

  13. Motivation and Test Anxiety in Test Performance across Three Testing Contexts: The CAEL, CET, and GEPT

    Science.gov (United States)

    Cheng, Liying; Klinger, Don; Fox, Janna; Doe, Christine; Jin, Yan; Wu, Jessica

    2014-01-01

    This study examined test-takers' motivation, test anxiety, and test performance across a range of social and educational contexts in three high-stakes language tests: the Canadian Academic English Language (CAEL) Assessment in Canada, the College English Test (CET) in the People's Republic of China, and the General English Proficiency Test (GEPT)…

  14. Noise and Vibration Modeling for Anti-Lock Brake Systems

    Science.gov (United States)

    Zhan, Wei

    A new methodology is proposed for noise and vibration analysis for Anti-Lock Brake Systems (ABS). First, a correlation between noise and vibration measurement data and simulation results need to be established. This relationship allows the engineers to focus on modeling and simulation instead of noise and vibration testing. A comprehensive ABS model is derived for noise and vibration study. The model can be set up to do different types of simulations for noise and vibration analysis. If some data is available from actual testing, then the test data can be easily imported into the model as an input to replace the corresponding part in the model. It is especially useful when the design needs to be modified, or trade-off between ABS performance and noise and vibration is necessary. The model can greatly reduce the time to market for ABS products. It also makes system level optimization possible.

  15. Performance Test for the SIGMA Communication System

    Directory of Open Access Journals (Sweden)

    Seonyeong Jeong

    2016-12-01

    Full Text Available Scientific CubeSat with Instruments for Global Magnetic Fields and Radiations (SIGMA is a 3-U size CubeSat that will be operated in low earth orbit (LEO. The SIGMA communication system uses a very high frequency (VHF band for uplink and an ultra high frequency (UHF band for downlink. Both frequencies belong to an amateur band. The ground station that communicates with SIGMA is located at Kyung Hee Astronomical Observatory (KHAO. For reliable communication, we carried out a laboratory (LAB test and far-field tests between the CubeSat and a ground station. In the field test, we considered test parameters such as attenuation, antenna deployment, CubeSat body attitude, and Doppler frequency shift in transmitting commands and receiving data. In this paper, we present a communication performance test of SIGMA, a link budget analysis, and a field test process. We also compare the link budget with the field test results of transmitting commands and receiving data.

  16. The Shock and Vibration Bulletin: Proceedings on the Symposium on ShocK and Vibration (52nd) Held in New Orleans, Louisiana on 26-28 October 1981. Part 3. Environmental Testing and Simulation, Flight Environments.

    Science.gov (United States)

    1982-05-01

    New York, NY ITIZ AND AUTHIORS OF PAPERS PRESENTED IN THE SHORT DISCUSSION TOPICS SESSION NOTE: lb... pepere were only pneemnteo at the Symposium...system then is to create the Gunfire vibration testing is typically per- desired line spectrum, fourier transform it formed on black boxes which do not

  17. Hidden dangers revealed by misdiagnosed diabetic neuropathy: A comparison of simple clinical tests for the screening of vibration perception threshold at primary care level.

    Science.gov (United States)

    Azzopardi, Kurt; Gatt, Alfred; Chockalingam, Nachiappan; Formosa, Cynthia

    2017-10-10

    Diabetic peripheral neuropathy is an important complication and contributes to the morbidity of diabetes mellitus. Evidence indicates early detection of diabetic peripheral neuropathy results in fewer foot ulcers and amputations. The aim of this study was to compare different screening modalities in the detection of diabetic peripheral neuropathy in a primary care setting. A prospective non-experimental comparative multi-centre cross sectional study was conducted in various Primary Health Centres. One hundred participants living with Type 2 diabetes for at least 10 years were recruited using a convenience sampling method. The Vibratip, 128Hz tuning fork and neurothesiometer were compared in the detection of vibration perception. This study showed different results of diabetic peripheral neuropathy screening tests, even in the same group of participants. This study has shown that the percentage of participants who did not perceive vibrations was highest when using the VibraTip (28.5%). This was followed by the neurothesiometer (21%) and the 128Hz tuning fork (12%) (pneuropathy in patients with diabetes is crucial. This study demonstrates that some instruments are more sensitive to vibration perception than others. We recommend that different modalities should be used in patients with diabetes and when results do not concur, further neurological evaluation should be performed. This would significantly reduce the proportion of patients with diabetes who would be falsely identified as having no peripheral neuropathy and subsequently denied the benefit of beneficial and effective secondary risk factor control. Copyright © 2017 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.

  18. Vibration analysis of cryocoolers

    Science.gov (United States)

    Tomaru, Takayuki; Suzuki, Toshikazu; Haruyama, Tomiyoshi; Shintomi, Takakazu; Yamamoto, Akira; Koyama, Tomohiro; Li, Rui

    2004-05-01

    The vibrations of Gifford-McMahon (GM) and pulse-tube (PT) cryocoolers were measured and analyzed. The vibrations of the cold-stage and cold-head were measured separately to investigate their vibration mechanisms. The measurements were performed while maintaining the thermal conditions of the cryocoolers at a steady state. We found that the vibration of the cold-head for the 4 K PT cryocooler was two orders of magnitude smaller than that of the 4 K GM cryocooler. On the other hand, the vibration of the cold-stages for both cryocoolers was of the same order of magnitude. From a spectral analysis of the vibrations and a simulation, we concluded that the vibration of the cold-stage is caused by an elastic deformation of the pulse tubes (or cylinders) due to the pressure oscillation of the working gas.

  19. Vibration analysis of cryocoolers

    Energy Technology Data Exchange (ETDEWEB)

    Tomaru, Takayuki; Suzuki, Toshikazu; Haruyama, Tomiyoshi; Shintomi, Takakazu; Yamamoto, Akira [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Koyama, Tomohiro; Rui Li [Sumitomo Heavy Industries Ltd., Tokyo (Japan)

    2004-05-01

    The vibrations of Gifford-McMahon (GM) and pulse-tube (PT) cryocoolers were measured and analyzed. The vibrations of the cold-stage and cold-head were measured separately to investigate their vibration mechanisms. The measurements were performed while maintaining the thermal conditions of the cryocoolers at a steady state. We found that the vibration of the cold-head for the 4 K PT cryocooler was two orders of magnitude smaller than that of the 4 K GM cryocooler. On the other hand, the vibration of the cold-stages for both cryocoolers was of the same order of magnitude. From a spectral analysis of the vibrations and a simulation, we concluded that the vibration of the cold-stage is caused by an elastic deformation of the pulse tubes (or cylinders) due to the pressure oscillation of the working gas. (Author)

  20. Field Test Data for Detecting Vibrations of a Building Using High-Speed Video Cameras

    Science.gov (United States)

    2017-10-01

    5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) US Army Research Laboratory ATTN: RDRL-SES-P 2800 Powder Mill Road...The team set up a low-frequency ServoDrive speaker inside of ARL’s Building 108 facility. In this experiment, the speaker generated tones at 19, 28...ground-truth data. The field test and the data collected are documented in this report. The team developed image processing algorithms to analyze the

  1. The Effects of Vibration Frequencies on Physical, Perceptual and Cognitive Performance

    Science.gov (United States)

    2006-10-01

    l’intégration d’un réseau multicouches de vétronique, dans lequel tous les systèmes pourront être accessibles sur chacun des postes de travail de l’équipe...fournir ainsi un environnement de travail suffisamment stable pour utiliser le réseau de vétronique. Une suspension active absorbe l’énergie dynamique...du sol , l’analyse, puis applique un signal d’énergie équivalent visant à compenser les aspérités du sol , ce qui permet d’amortir les vibrations lors

  2. Performance tests on the NRPB thermoluminescent dosemeter

    CERN Document Server

    Shaw, K B

    1977-01-01

    Performance tests on the thermoluminescent dosemeter, designed at NRPB for use in the automated personal dosimetry system, are described. An ultra-thin lithium borate dosemeter has been developed for skin absorbed dose measurement. The X-ray, gamma-ray and beta-ray energy response of the dosemeter has been investigated and the angular response for the dosemeter has been examined. The annealing, read-out and stabilisation procedures for the dosemeter are described.

  3. Testing Devices Garner Data on Insulation Performance

    Science.gov (United States)

    2014-01-01

    To develop a test instrument that could garner measurements of the thermal performance of insulation under extreme conditions, researchers at Kennedy Space Center devised the Cryostat 1 and then Cryostat 2. McLean, Virginia-based QinetiQ North America licensed the technology and plans to market it to organizations developing materials for things like piping and storage tank insulation, refrigeration, appliances, and consumer goods.

  4. A low cycle fatigue test device for micro-cantilevers based on self-excited vibration principle.

    Science.gov (United States)

    Qi, Mingjing; Liu, Zhiwei; Yan, Xiaojun

    2014-10-01

    This paper reports a low-cycle fatigue test device for micro-cantilevers, which are widely used in micro scale structures. The working principle of the device is based on the phenomenon that a micro-cantilever can be set into self-excited vibration between two electrodes under DC voltage. Compared with previous devices, this simple device can produce large strain amplitude on non-notched specimens, and allows a batch of specimens to be tested simultaneously. Forty-two micro-cantilever specimens were tested and their fatigue fracture surfaces exhibit typical low cycle fatigue characteristics. As such, the device is very attractive for future fatigue investigation for micro scale structures.

  5. The effects of suspension particle size on the performance of air-jet, ultrasonic and vibrating-mesh nebulisers.

    Science.gov (United States)

    Najlah, Mohammad; Parveen, Ishrat; Alhnan, Mohamed Albed; Ahmed, Waqar; Faheem, Ahmed; Phoenix, David A; Taylor, Kevin M G; Elhissi, Abdelbary

    2014-01-30

    Using latex microspheres as model suspensions, the influence of suspension particle size (1, 4.5 and 10 μm) on the properties of aerosols produced using Pari LC Sprint (air-jet), Polygreen (ultrasonic), Aeroneb Pro (actively vibrating-mesh) and Omron MicroAir NE-U22 (passively vibrating-mesh) nebulisers was investigated. The performance of the Pari nebuliser was independent of latex spheres particle size. For both Polygreen and Aeroneb Pro nebulizers, total aerosol output increased when the size of latex spheres increased, with highest fine particle fraction (FPF) values being recorded. However, following nebulisation of 1 or 4.5 μm suspensions with the Polygreen device, no particles were detected in the aerosols deposited in a two-stage impinger, suggesting that the aerosols generated from this device consisted mainly of the continuous phase while the dispersed microspheres were excluded and remained in the nebuliser. The Omron nebuliser efficiently nebulised the 1 μm latex spheres, with high output rate and no particle aggregation. However, this device functioned inefficiently when delivering 4.5 or 10 μm suspensions, which was attributed to the mild vibrations of its mesh and/or the blockage of the mesh apertures by the microspheres. The Aeroneb Pro fragmented latex spheres into smaller particles, but uncontrolled aggregation occurred upon nebulisation. This study has shown that the design of the nebuliser influenced the aerosol properties using latex spheres as model suspensions. Moreover, for the recently marketed mesh nebulisers, the performance of the Aeroneb Pro device was less dependent on particle size of the suspension compared with the Omron MicroAir nebuliser. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Gearbox vibration diagnostic analyzer

    Science.gov (United States)

    1992-01-01

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

  7. Vibration Testing Procedures for Bone Stiffness Assessment in Fractures Treated with External Fixation.

    Science.gov (United States)

    Mattei, Lorenza; Longo, Antonia; Di Puccio, Francesca; Ciulli, Enrico; Marchetti, Stefano

    2017-04-01

    A bone healing assessment is crucial for the successful treatment of fractures, particularly in terms of the timing of support devices. However, in clinical practice, this assessment is only made qualitatively through bone manipulation and X-rays, and hence cannot be repeated as often as might be required. The present study reconsiders the quantitative method of frequency response analysis for healing assessments, and specifically for fractures treated with an external fixator. The novelty consists in the fact that bone excitation and response are achieved through fixator pins, thus overcoming the problem of transmission through soft-tissues and their damping effect. The main objective was to develop and validate a test procedure in order to characterize the treated bone. More than 80 tests were performed on a tibia phantom alone, a phantom with pins, and a phantom with a complete fixator. Different excitation techniques and input-output combinations were compared. The results demonstrated the effectiveness of a procedure based on impact tests using a micro-hammer. Pins and fixator were demonstrated to influence the frequency response of the phantom by increasing the number of resonant frequencies. This procedure will be applied in future studies to monitor healing both in in vitro and in vivo conditions.

  8. Performance Tests for Bubble Blockage Device

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Kwang Soon; Wi, Kyung Jin; Park, Rae Joon; Wan, Han Seong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Postulated severe core damage accidents have a high threat risk for the safety of human health and jeopardize the environment. Versatile measures have been suggested and applied to mitigate severe accidents in nuclear power plants. To improve the thermal margin for the severe accident measures in high-power reactors, engineered corium cooling systems involving boiling-induced two-phase natural circulation have been proposed for decay heat removal. A boiling-induced natural circulation flow is generated in a coolant path between a hot vessel wall and cold coolant reservoir. In general, it is possible for some bubbles to be entrained in the natural circulation loop. If some bubbles entrain in the liquid phase flow passage, flow instability may occur, that is, the natural circulation mass flow rate may be oscillated. A new device to block the entraining bubbles is proposed and verified using air-water test loop. To avoid bubbles entrained in the natural circulation flow loop, a new device was proposed and verified using an air-water test loop. The air injection and liquid circulation loop was prepared, and the tests for the bubble blockage devices were performed by varying the geometry and shape of the devices. The performance of the bubble blockage device was more effective as the area ratio of the inlet to the down-comer increased, and the device height decreased. If the device has a rim to generate a vortex zone, the bubbles will be most effectively blocked.

  9. Urban vibrations

    DEFF Research Database (Denmark)

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

    2012-01-01

      lab   studies   in   that   we   found   a   decreased   detection   rate   in   busy   environments.   Here   we   test   with   a   much   larger   sample   and   age   range,   and   contribute   with   the   first   vibration  sensitivity  testing  outside  the  lab  in  an  urban   public...

  10. Note: A kinematic shaker system for high amplitude, low frequency vibration testing.

    Science.gov (United States)

    Swaminathan, Anand; Poese, Matthew E; Smith, Robert W M; Garrett, Steven L

    2015-11-01

    This note describes a shaker system capable of high peak-velocity, large amplitude, low frequency, near-sinusoidal excitation that has been constructed and employed in experiments on the inhibition of Rayleigh-Bénard convection using acceleration modulation. The production of high peak-velocity vibration is of interest in parametric excitation problems of this type and reaches beyond the capabilities of standard electromagnetic shakers. The shaker system described employs a kinematic linkage to two counter-rotating flywheels, driven by a variable-speed electrical motor, producing peak-to-peak displacements of 15.24 cm to a platform mounted on two guide rails. In operation, this shaker has been demonstrated to produce peak speeds of up to 3.7 m/s without failure.

  11. A novel bending fatigue test device based on self-excited vibration principle and its application to superelastic Nitinol microwire study

    Science.gov (United States)

    Leng, Jiaming; Yan, Xiaojun; Zhang, Xiaoyong; Qi, Mingjing; Liu, Zhiwei; Huang, Dawei

    2017-10-01

    Most Nitinol-alloy-based biomedical devices are usually manufactured from straight drawn microwires or microbeams. Fatigue due to cyclic bending is interpreted as the primary failure mechanism in these devices. However, the bending fatigue performance of a Nitinol microwire is rarely studied because of the lack of test devices. Therefore, we firstly establish a bending fatigue test device based on the self-excited vibration principle. Then, we further improve and experimentally verify the device in three aspects to enlarge the strain amplitude: electrode distance optimization, electrode placement angle optimization and local stiffness enhancement. Based on these improvements, the strain amplitude is increased to 6%, successfully meeting the requirements of Nitinol microwire bending fatigue tests. Using the improved test device, a group of superelastic Nitinol (55.8% Ni-44.2% Ti) microwires with a diameter of 50.8 μm are tested. The test results show that the fatigue strain limit for the chosen life (1 × 106 cycles) is around 1.9%, and the inflexion appears at a strain amplitude of 2.3%. SEM observation shows the typical features of low-cycle and high-cycle fatigue on the fracture surfaces.

  12. Performance testing of a hydrogen heat pipe

    Science.gov (United States)

    Alario, J.; Kosson, R.

    1980-01-01

    Test results are presented for a reentrant groove heat pipe with hydrogen working fluid. The heat pipe became operational between 20 and 30 K after a cooldown from 77 K without any difficulty. Steady-state performance data taken over a 19 to 23 K temperature range indicated the following: (1) maximum heat transport capacity = 5.4 W-m; (2) static wicking height = 1.42 cm; and (3) overall heat pipe conductance = 1.7 W/C. These data agreed remarkably well with extrapolations made from comparable ammonia test results. The maximum heat transport capacity is 9.5% larger than the extrapolated value, but the static wicking height is the same. The overall conductance is 29% of the ammonia value, which is close to the ratio of liquid thermal conductivities (24%). Also, recovery from a completely frozen condition was accomplished within 5 min by simply applying an evaporater heat load of 1.8 W.

  13. Eurados trial performance test for photon dosimetry

    DEFF Research Database (Denmark)

    Stadtmann, H.; Bordy, J.M.; Ambrosi, P.

    2001-01-01

    Within the framework of the EURADOS Action entitled Harmonisation and Dosimetric Quality Assurance in Individual Monitoring for External Radiation, trial performance tests for whole-body and extremity personal dosemeters were carried out. Photon, beta and neutron dosemeters were considered...... 312 single results, 26 fell outside the limits of the trumpet curve and 32 were outside the range 1/1.5 to 1.5. Most outliers resulted from high energy R-F irradiations without electronic equilibrium. These fields are not routinely encountered by many of the participating dosimetry services...

  14. Fuel accident performance testing for small HTRs

    Science.gov (United States)

    Schenk, W.; Pott, G.; Nabielek, H.

    1990-04-01

    Irradiated spherical fuel elements containing 16400 coated UO 2 particles each were heated at temperatures between 1600 and 1800°C and the fission product release was measured. The demonstrated fission product retention at 1600°C establishes the basis for the design of small modular HTRs which inherently limit the temperature to 1600°C by passive means. In addition to this demonstration, the test data show that modern TRISO fuels provide an ample performance margin: release normally sets in at 1800°C; this occurs at 1600°C only with fuels irradiated under conditions which significantly exceed current reactor design requirements.

  15. PERFORMANCE TESTING AND ANALYSIS OF CUPOLA FURNACE

    OpenAIRE

    PROF.HEMANT R. BHAGAT-PATIL; MEGHA S. LONDHEKAR

    2013-01-01

    In today’s industrial scenario huge losses/wastage occur in the manufacturing shop floor and foundry industries. The efficiency of any foundry largely depends on the efficiency of the melting process amulti-step operation where the metal is heated, treated, alloyed, and transported into die or mold cavities to form a casting. In this paper we represents the performance testing and analysis of Cupola Furnace, and reduces the problems occurs to give the best results. Our main focus in this work...

  16. Comparison of whole-body vibration exercise and plyometric exercise to improve isokinetic muscular strength, jumping performance and balance of female volleyball players

    Science.gov (United States)

    Kim, Yong-Youn; Park, Si-Eun

    2016-01-01

    [Purpose] The purpose of this study was to assess the effect of whole-body vibration exercise and plyometric exercise on female volleyball players. [Subjects and Methods] Subjects were randomly allocated to two exercise groups (whole-body vibration exercise group and plyometric exercise group). The exercise was conducted three times each week for 8 weeks. Isokinetic muscular strength, jumping performance, and balance were measured before starting the exercise and after finishing the 8 weeks of exercise. [Results] Measurements of isokinetic muscular strength revealed that the whole-body vibration exercise group showed significant increase after the exercise. However, the plyometric exercise group had no significant increase in lumbar flexion, extension, and knee flexion. Measurements of vertical jumping revealed that, the whole-body vibration exercise group had no significant increase after the exercise. However, the plyometric exercise group showed significant increase. Measurements of balance revealed that, the whole-body vibration exercise group showed significant increase. However, the plyometric exercise group showed no significant increase. [Conclusion] Although both whole-body vibration and plyometric exercises are effective intervention methods, the two methods have different effects on the improvement of isokinetic muscular strength, jumping performance, and balance of female volleyball players. PMID:27942136

  17. Analysis of Within-Test Variability of Non-Destructive Test Methods to Evaluate Compressive Strength of Normal Vibrated and Self-Compacting Concretes

    Science.gov (United States)

    Nepomuceno, Miguel C. S.; Lopes, Sérgio M. R.

    2017-10-01

    Non-destructive tests (NDT) have been used in the last decades for the assessment of in-situ quality and integrity of concrete elements. An important step in the application of NDT methods concerns to the interpretation and validation of the test results. In general, interpretation of NDT results should involve three distinct phases leading to the development of conclusions: processing of collected data, analysis of within-test variability and quantitative evaluation of property under investigation. The analysis of within-test variability can provide valuable information, since this can be compared with that of within-test variability associated with the NDT method in use, either to provide a measure of the quality control or to detect the presence of abnormal circumstances during the in-situ application. This paper reports the analysis of the experimental results of within-test variability of NDT obtained for normal vibrated concrete and self-compacting concrete. The NDT reported includes the surface hardness test, ultrasonic pulse velocity test, penetration resistance test, pull-off test, pull-out test and maturity test. The obtained results are discussed and conclusions are presented.

  18. Oscillatory whole-body vibration improves exercise capacity and physical performance in pulmonary arterial hypertension: a randomised clinical study.

    Science.gov (United States)

    Gerhardt, Felix; Dumitrescu, Daniel; Gärtner, Carina; Beccard, Ralf; Viethen, Thomas; Kramer, Tilmann; Baldus, Stephan; Hellmich, Martin; Schönau, Eckhard; Rosenkranz, Stephan

    2017-04-01

    In patients with pulmonary arterial hypertension (PAH), supportive therapies may be beneficial in addition to targeted medical treatment. Here, we evaluated the effectiveness and safety of oscillatory whole-body vibration (WBV) in patients on stable PAH therapy. Twenty-two patients with PAH (mean PAP≥25 mm Hg and pulmonary arterial wedge pressure (PAWP)≤15 mm Hg) who were in world health organization (WHO)-Functional Class II or III and on stable PAH therapy for≥3 months, were randomised to receive WBV (16 sessions of 1-hour duration within 4 weeks) or to a control group, that subsequently received WBV. Follow-up measures included the 6-min walking distance (6MWD), cardiopulmonary exercise testing (CPET), echocardiography, muscle-power, and health-related quality of life (HRQoL; SF-36 and LPH questionnaires). When compared to the control group, patients receiving WBV exhibited a significant improvement in the primary endpoint, the 6MWD (+35.4±10.9 vs -4.4±7.6 m), resulting in a net benefit of 39.7±7.8 m (p=0.004). WBV was also associated with substantial improvements in CPET variables, muscle power, and HRQoL. The combined analysis of all patients (n=22) indicated significant net improvements versus baseline in the 6MWD (+38.6 m), peakVO2 (+65.7 mL/min), anaerobic threshold (+40.9 mL VO2/min), muscle power (+4.4%), and HRQoL (SF-36 +9.7, LPH -11.5 points) (all p<0.05). WBV was well tolerated in all patients, and no procedure-related severe adverse events (SAEs) occurred. WBV substantially improves exercise capacity, physical performance, and HRQoL in patients with PAH who are on stable targeted therapy. This methodology may be utilised in structured training programmes, and may be feasible for continuous long-term physical exercise in these patients. NCT01763112; Results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  19. Standard specification for agencies performing nondestructive testing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This specification covers minimum requirements for agencies performing nondestructive testing (NDT). 1.2 When using this specification to assess the capability of, or to accredit NDT agencies, Guide E 1359 shall be used as a basis for the survey. It can be supplemented as necessary with more detail in order to meet the auditor's specific needs. 1.3 This specification can be used as a basis to evaluate testing or inspection agencies, or both, and is intended for use for the qualifying or accrediting, or both, of testing or inspection agencies, public or private. 1.4 The use of SI or inch-pound units, or combination thereof, will be the responsibility of the technical committee whose standards are referred to in this standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to...

  20. Bevel Gearbox Fault Diagnosis using Vibration Measurements

    Directory of Open Access Journals (Sweden)

    Hartono Dennis

    2016-01-01

    Full Text Available The use of vibration measurementanalysis has been proven to be effective for gearbox fault diagnosis. However, the complexity of vibration signals observed from a gearbox makes it difficult to accurately detectfaults in the gearbox. This work is based on a comparative studyof several time-frequency signal processing methods that can be used to extract information from transient vibration signals containing useful diagnostic information. Experiments were performed on a bevel gearbox test rig using vibration measurements obtained from accelerometers. Initially, thediscrete wavelet transform was implementedfor vibration signal analysis to extract the frequency content of signal from the relevant frequency region. Several time-frequency signal processing methods werethen incorporated to extract the fault features of vibration signals and their diagnostic performances were compared. It was shown thatthe Short Time Fourier Transform (STFT could not offer a good time resolution to detect the periodicity of the faulty gear tooth due the difficulty in choosing an appropriate window length to capture the impulse signal. The Continuous Wavelet Transform (CWT, on the other hand, was suitable to detection of vibration transients generated by localized fault from a gearbox due to its multi-scale property. However, both methods still require a thorough visual inspection. In contrast, it was shown from the experiments that the diagnostic method using the Cepstrumanalysis could provide a direct indication of the faulty tooth without the need of a thorough visual inspection as required by CWT and STFT.

  1. Analysis and testing of an inner bypass magnetorheological damper for shock and vibration mitigation

    Science.gov (United States)

    Bai, Xian-Xu; Hu, Wei; Wereley, Norman M.

    2013-04-01

    Aiming at fundamentally improving the performance of MR dampers, including maximizing dynamic range (i.e., ratio of field-on to field-off damping force) while simultaneously minimizing field-off damping force, this study presents the principle of an inner bypass magnetorheological damper (IBMRD). The IBMRD is composed of a pair of twin tubes, i.e., the inner tube and outer concentric tube, a movable piston-shaft arrangement, and an annular MR fluid flow gap sandwiched between the concentric tubes. In the IBMRD, the inner tube serves simultaneously as the guide for the movable piston and the bobbin for the electromagnetic coil windings, and five active rings on the inner tube, annular MR fluid flow gap, and outer tube forms five closed magnetic circuits. The annular fluid flow gap is an inner bypass annular valve where the rheology of the MR fluids, and hence the damping force of the MR damper, is controlled. Based on the structural principle of the IBMRD, the IBMRD is configured and its finite element analysis (FEA) is implemented. After theoretically constructing the hydro-mechanical model for the IBMRD, its mathematical model is established using a Bingham-plastic nonlinear fluid model. The characteristics of the IBMRD are theoretically evaluated and compared to those of a conventional piston-bobbin MR damper with an identical active length and cylinder diameter. In order to validate the theoretical results predicted by the mathematical model, the prototype IBMRD is designed, fabricated, and tested. The servo-hydraulic testing machine (type: MTS 810) and rail-guided drop tower are used to provide sinusoidal displacement excitation and shock excitation to the IBMRD, respectively.

  2. Effect of whole-body vibration on neuromuscular performance and body composition for females 65 years and older: a randomized-controlled trial.

    Science.gov (United States)

    von Stengel, S; Kemmler, W; Engelke, K; Kalender, W A

    2012-02-01

    We examined whether the effect of multipurpose exercise can be enhanced by whole-body vibration (WBV). One hundred and fifty-one post-menopausal women (68.5 ± 3.1 years) were randomly assigned to three groups: (1) a training group (TG); (2) training including vibration (VTG); and (3) a wellness control group (CG). TG and VTG performed the same training program twice weekly (60 min), consisting of aerobic and strength exercises, with the only difference that leg strength exercises (15 min) were performed with (VTG) or without (TG) vibration. CG performed a low-intensity "wellness" program. At baseline and after 18 months, body composition was determined using dual-X-ray-absorptiometry. Maximum isometric strength was determined for the legs and the trunk region. Leg power was measured by countermovement jumps using a force-measuring plate. In the TG lean body mass, total body fat, and abdominal fat were favorably affected, but no additive effects were generated by the vibration stimulus. However, concerning muscle strength and power, there was a tendency in favor of the VTG. Only vibration training resulted in a significant increase of leg and trunk flexion strength compared with CG. In summary, WBV embedded in a multipurpose exercise program showed minor additive effects on body composition and neuromuscular performance. © 2010 John Wiley & Sons A/S.

  3. Progress Letter Report on Bending Fatigue Test System Development for Spent Nuclear Fuel Vibration Integrity Study (Out-of-cell fatigue testing development - Task 2.4)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [ORNL; Wang, Hong [ORNL; Cox, Thomas S [ORNL; Baldwin, Charles A [ORNL; Bevard, Bruce Balkcom [ORNL

    2013-08-01

    Vibration integrity of high burn-up spent nuclear fuel in transportation remains to be a critical component of US nuclear waste management system. The structural evaluation of package for spent fuel transportation eventually will need to see if the content or spent fuel is in a subcritical condition. However, a system for testing and characterizing such spent fuel is still lacking mainly due to the complication involved with dealing radioactive specimens in a hot cell environment. Apparently, the current state-of-the-art in spent fuel research and development is quite far away from the delivery of reliable mechanical property data for the assessment of spent fuels in the transport package evaluation. Under the sponsorship of US NRC, ORNL has taken the challenge in developing a robust testing system for spent fuel in hot cell. An extensive literature survey was carried out and unique requirements of such testing system were identified. The U-frame setup has come to the top among various designs examined for reverse bending fatigue test of spent fuel rod. The U-frame has many features that deserve mentioned here: Easy to install spent fuel rod in test; Less linkages than in conventional bending test setup such as three-point or four-point bending; Target the failure mode relevant to the fracture of spent fuel rod in transportation by focusing on pure bending; The continuous calibrations and modifications resulted in the third generation (3G) U-frame testing setup. Rigid arms are split along the LBB axis at rod sample ends. For each arm, this results in a large arm body and an end piece. Mating halves of bushings were modified into two V-shaped surfaces on which linear roller bearings (LRB) are embedded. The rod specimen is installed into the test fixture through opening and closing slide end-pieces. The 3G apparently has addressed major issues of setup identified in the previous stage and been proven to be eligible to be further pursued in this project. On the other

  4. Defects detection on the welded reinforcing steel with self-shielded wires by vibration tests

    Directory of Open Access Journals (Sweden)

    Crâştiu Ion

    2017-01-01

    Full Text Available The aim of this paper is the development and validation of a vibroacustic technique to welding defects detection, especially for welded reinforcing structures. In welded structures subjected to dynamic cyclic loads may appear and propagate fatigue cracks due to local structural damage. These cracks may initiate due to the technological parameters used in welding process, or due to environmental operating conditions. By the means of Finite Element Method (FEM, the natural frequencies and shape modes of more welded steel specimens are determined. The analysis is carried out in undamaged condition as well as damaged one, after artificially induced damages. The experimental measurement of the vibroacustic response is carried out by using a condenser microphone, which is suitable for high-fidelity acoustic measurements in the frequency range of 20 – 20.000 Hz. The vibration responses of the welded specimens, in free-free conditions, are carried out using algorithms based on Fast Fourier Transform (FFT, and Prony's series. The results are compared to modal parameters estimated using FE Analysis.

  5. Max Launch Abort System (MLAS) Pad Abort Test Vehicle (PATV) II Attitude Control System (ACS) Integration and Pressurization Subsystem Dynamic Random Vibration Analysis

    Science.gov (United States)

    Ekrami, Yasamin; Cook, Joseph S.

    2011-01-01

    In order to mitigate catastrophic failures on future generation space vehicles, engineers at the National Aeronautics and Space Administration have begun to integrate a novel crew abort systems that could pull a crew module away in case of an emergency at the launch pad or during ascent. The Max Launch Abort System (MLAS) is a recent test vehicle that was designed as an alternative to the baseline Orion Launch Abort System (LAS) to demonstrate the performance of a "tower-less" LAS configuration under abort conditions. The MLAS II test vehicle will execute a propulsive coast stabilization maneuver during abort to control the vehicles trajectory and thrust. To accomplish this, the spacecraft will integrate an Attitude Control System (ACS) with eight hypergolic monomethyl hydrazine liquid propulsion engines that are capable of operating in a quick pulsing mode. Two main elements of the ACS include a propellant distribution subsystem and a pressurization subsystem to regulate the flow of pressurized gas to the propellant tanks and the engines. The CAD assembly of the Attitude Control System (ACS) was configured and integrated into the Launch Abort Vehicle (LAV) design. A dynamic random vibration analysis was conducted on the Main Propulsion System (MPS) helium pressurization panels to assess the response of the panel and its components under increased gravitational acceleration loads during flight. The results indicated that the panels fundamental and natural frequencies were farther from the maximum Acceleration Spectral Density (ASD) vibrations which were in the range of 150-300 Hz. These values will direct how the components will be packaged in the vehicle to reduce the effects high gravitational loads.

  6. In-situ testing of the liquefaction potential of soft ground using an s-wave vibrator and seismic cones. Part 1. System, concept and preliminary test result; S ha vibrator oyobi seismic cone wo mochiita gen`ichi jiban ekijoka potential no hyoka. 1. System kosei oyobi genchi yosatsu keisoku kekka

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    For the purpose of evaluating liquefaction in situ, it was proposed that an S-wave vibrator designed to serve as a source in a reflection exploration method be utilized as a strong vibration generating source, and measurement was conducted in this connection. Equipment used in this test included an S-wave vibrator, static cone penetration machine, and various measuring cones. A multiplicity of measuring cones had been inserted beforehand into the target layers and comparison layers, and changes upon vibrator activation were measured. On a dry bed of the Tonegawa river, a 40m{sup 2} field was set up, and 41 cone penetration tests were conducted, with the cones positioned zigzag at 5m intervals. In this way, the ground structure was disclosed from the surface to the 10m-deep level. For the measurement, 3-component cones and seismic cones were placed at prescribed depths, and fluctuations and waveforms presented by pore water pressure at each level were determined with the vibration source changing its place. It was found that the changes in the pore water pressure exposed to vibration assume characteristic patterns corresponding to the conditions of vibration application. 5 figs., 1 tab.

  7. Stochastic Modeling of Structural Uncertainty/Variability from Ground Vibration Modal Test Data (Postprint)

    Science.gov (United States)

    2012-07-01

    inclusion of a nonlinear bend–twist couple without permanent deformation of the test article. For modal testing, a Polytec PSV -400-3D scanning laser...scanned using the Polytec PSV -400-3D scanning LDV. The joined-wing test article was excited with an autoping hammer with a force sensor mounted to the

  8. Functional Performance Testing for Power and Return to Sports

    Science.gov (United States)

    Manske, Robert; Reiman, Michael

    2013-01-01

    Context: Functional performance testing of athletes can determine physical limitations that may affect sporting activities. Optimal functional performance testing simulates the athlete’s activity. Evidence Acquisition: A Medline search from 1960 to 2012 was implemented with the keywords functional testing, functional impairment testing, and functional performance testing in the English language. Each author also undertook independent searches of article references. Conclusion: Functional performance tests can bridge the gap between general physical tests and full, unrestricted athletic activity. PMID:24427396

  9. A critical review of the neurophysiological evidence underlying clinical vestibular testing using sound, vibration and galvanic stimuli.

    Science.gov (United States)

    Curthoys, Ian S

    2010-02-01

    In addition to activating cochlear receptors, air conducted sound (ACS) and bone conducted vibration (BCV) activate vestibular otolithic receptors, as shown by neurophysiological evidence from animal studies--evidence which is the foundation for using ACS and BCV for clinical vestibular testing by means of vestibular-evoked myogenic potentials (VEMPs). Recent research is elaborating the specificity of ACS and BCV on vestibular receptors. The evidence that saccular afferents can be activated by ACS has been mistakenly interpreted as showing that ACS only activates saccular afferents. That is not correct - ACS activates both saccular and utricular afferents, just as BCV activates both saccular and utricular afferents, although the patterns of activation for ACS and BCV do not appear to be identical. The otolithic input to sternocleidomastoid muscle appears to originate predominantly from the saccular macula. The otolithic input to the inferior oblique appears to originate predominantly from the utricular macula. Galvanic stimulation by surface electrodes on the mastoids very generally activates afferents from all vestibular sense organs. This review summarizes the physiological results, the potential artifacts and errors of logic in this area, reconciles apparent disagreements in this field. The neurophysiological results on BCV have led to a new clinical test of utricular function - the n10 of the oVEMP. The cVEMP tests saccular function while the oVEMP tests utricular function. Copyright (c) 2009 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  10. Tactile direction discrimination and vibration detection in diabetic neuropathy.

    Science.gov (United States)

    Löken, Linda S; Lundblad, L C; Elam, M; Olausson, H W

    2010-05-01

    To evaluate the clinical usefulness of quantitative testing of tactile direction discrimination (TDD) in patients with diabetic neuropathy. TDD and vibration detection were examined on the dorsum of the feet in 43 patients with type 1 diabetes mellitus and clinical signs and symptoms indicating mild neuropathy, and abnormal results for neurography, temperature detection, or heart rate variability. Test-retest examination of TDD was performed in nine of the patients. Twenty-six of the patients had abnormal TDD (sensitivity 0.60) and 20 had abnormal vibration detection (sensitivity 0.46). Ten of the patients had abnormal TDD and normal vibration detection. Four of the patients had abnormal vibration detection and normal TDD. Test-retest examination of TDD showed a high degree of reproducibility (r = 0.87). TDD seems more useful than vibration detection in examination of diabetic neuropathy.

  11. Changes in muscle cross-sectional area, muscle force, and jump performance during 6 weeks of progressive whole-body vibration combined with progressive, high intensity resistance training

    Science.gov (United States)

    Rosenberger, A.; Beijer, Å.; Johannes, B.; Schoenau, E.; Mester, J.; Rittweger, J.; Zange, J.

    2017-01-01

    Objectives: We hypothesized that progressive whole-body vibration (WBV) superimposed to progressive high intensity resistance training has greater effects on muscle cross-sectional area (CSA), muscle force of leg muscles, and jump performance than progressive high intensity resistance training alone. Methods: Two groups of healthy male subjects performed either 6 weeks of Resistive Vibration Exercise (RVE, squats and heel raises with WBV, n=13) or Resistive Exercise (RE, squats and heel raises without WBV, n=13). Squats under RVE required indispensable weight loading on the forefoot to damp harmful vibrations to the head. Time, intervention, and interaction effects were analyzed. Results: After 6 weeks of training, knee extensor CSA, isometric knee extension force, and counter movement jump height increased equally in both groups (time effect, Ptraining effects than RE only in plantar flexor muscles. RVE seems to be suitable in professional sports with a special focus on calf muscles. PMID:28574410

  12. Effectiveness of an Occupational Health Intervention Program to Reduce Whole Body Vibration Exposure: An Evaluation Study With a Controlled Pretest-Post-test Design

    NARCIS (Netherlands)

    Tiemessen, Ivo J. H.; Hulshof, Carel T. J.; Frings-Dresen, Monique H. W.

    2009-01-01

    Background An effective intervention program aiming to reduce whole body vibration (WBV) exposure at work will reduce the number of low back complaints in the near future. Methods An evaluation study with a controlled pretest-post-test design. Nine companies and 126 drivers were included in the

  13. Effect of stochastic resonance whole body vibration on functional performance in the frail elderly: A pilot study.

    Science.gov (United States)

    Kessler, Jessica; Radlinger, Lorenz; Baur, Heiner; Rogan, Slavko

    2014-01-01

    The aim of this pilot study was to evaluate the feasibility and the effect size of a four-week stochastic resonance whole body vibration (SR-WBV) intervention on functional performance and strength in frail elderly individuals. Twenty-seven participants have been recruited and randomly distributed in an intervention group (IG) and a sham group (SG). Primary outcomes were feasibility objectives like recruitment, compliance and safety. Secondary outcomes were short physical performance battery (SPPB), isometric maximum voluntary contraction (IMVC) and isometric rate of force development (IRFD). The intervention was feasible and safe. Furthermore it showed significant effects (p=0.035) and medium effect size (0.43) within the IG in SPPB. SR-WBV training over four weeks with frail elderly individuals is a safe intervention method. The compliance was good and SR-WBV intervention seems to improve functional performance. Further research over a longer time frame for the strength measurements (IMVC and IRFD) is needed to detect potential intervention effects in the force measurements as well. Clinical Trial register: NTC01704976. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. An evaluation of iced bridge hanger vibrations through wind tunnel testing and quasi-steady theory

    DEFF Research Database (Denmark)

    Gjelstrup, Henrik; Georgakis, Christos T.; Larsen, A.

    2012-01-01

    for wind perpendicular to the cylinder at velocities below 30 m/s and for temperatures between -5C and -1C. Aerodynamic drag, lift and moment coefficients are obtained from the static tests, whilst mean and fluctuating responses are obtained from the dynamic tests. The influence of varying surface...... roughness is also examined. The static force coefficients are used to predict parameter regions where aerodynamic instability of the iced bridge hanger might be expected to occur, through use of an adapted theoretical 3- DOF quasi-steady galloping instability model, which accounts for sectional axial...

  15. DEGASSING OF ALUMINUM A356 ALLOY USING ULTRASONIC VIBRATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hanbing [University of Tennessee, Knoxville (UTK); Meek, Thomas T. [University of Tennessee, Knoxville (UTK); Han, Qingyou [ORNL

    2007-01-01

    In order to investigate the effects of ultrasonic vibration on degassing of aluminum alloys, three experimental systems have been designed and built: one for ultrasonic degassing in open air, one for ultrasonic degassing under reduced pressure, and one for ultrasonic degassing with a purging gas. Experiments were first carried out in air to test degassing using ultrasonic vibration alone. The limitations with ultrasonic degassing were outlined. Further experiments were then performed under reduced pressures and in combination with purging argon gas. Experimental results suggest that ultrasonic vibration alone is efficient for degassing a small volume of melt. Ultrasonic vibration can be used for assisting vacuum degassing, making vacuum degassing much faster than that without using ultrasonic vibration. Ultrasonically assisted argon degassing is the fastest method for degassing among the three methods tested in this research. More importantly, dross formation during ultrasonically assisted argon degassing is much less than that during argon degassing. The mechanisms of ultrasonic degassing are discussed.

  16. An Evaluation of Test and Physical Uncertainty of Measuring Vibration in Wooden Junctions

    DEFF Research Database (Denmark)

    Dickow, Kristoffer Ahrens; Kirkegaard, Poul Henning; Andersen, Lars Vabbersgaard

    2012-01-01

    In the present paper a study of test and material uncertainty in modal analysis of certain wooden junctions is presented. The main structure considered here is a T-junction made from a particleboard plate connected to a spruce beam of rectangular cross section. The size of the plate is 1.2 m by 0...

  17. Whole body vibration in sport: a critical review.

    Science.gov (United States)

    Costantino, C; Gimigliano, R; Olvirri, S; Gimigliano, F

    2014-12-01

    Whole body vibration training is a recent area of study in athletic conditioning, health and rehabilitation. This paper provides a review of the effectiveness of this type of training in sport. A search was conducted across several electronic databases and studies on effects of whole body vibration training on sport performance were reviewed. Thirteen articles were included in the final analysis. The following variables were considered: participants investigated (sex and age), characteristics of the vibration (frequency and amplitude), training (type of sport, exposure time and intensity, tests used, type of study, effects examined and results obtained). This review considers proposed neural mechanisms and identifies studies that have demonstrated the effectiveness of WBV in sports. It considers where WBV might act and suggests that vibration can be an effective training stimulus. Future studies should focus on evaluating the long-term effects of vibration training and identify optimum frequency and amplitude, improve strength and muscular performance.

  18. Experimental Issues in Testing a Semiactive Technique to Control Earthquake Induced Vibration

    Directory of Open Access Journals (Sweden)

    Nicola Caterino

    2014-01-01

    Full Text Available This work focuses on the issues to deal with when approaching experimental testing of structures equipped with semiactive control (SA systems. It starts from practical experience authors gained in a recent wide campaign on a large scale steel frame structure provided with a control system based on magnetorheological dampers. The latter are special devices able to achieve a wide range of physical behaviours using low-power electrical currents. Experimental activities involving the use of controllable devices require special attention in solving specific aspects that characterize each of the three phases of the SA control loop: acquisition, processing, and command. Most of them are uncommon to any other type of structural testing. This paper emphasizes the importance of the experimental assessment of SA systems and shows how many problematic issues likely to happen in real applications are also present when testing these systems experimentally. This paper highlights several problematic aspects and illustrates how they can be addressed in order to achieve a more realistic evaluation of the effectiveness of SA control solutions. Undesired and unavoidable effects like delays and control malfunction are also remarked. A discussion on the way to reduce their incidence is also offered.

  19. Scanning slit for HIE-ISOLDE: vibrations test (linear motion actuator from UHV design, MAXON brushless motor, speed = 10 mm/s)

    CERN Document Server

    Bravin, E; Sosa, A

    2014-01-01

    This report summarizes the results of a series of tests performed on the prototype HIE-ISOLDE diagnostic box (HIE-DB) regarding the vibrations and drifts in the transverse position of the scanning blade while moving in and out of beam path in the HIE-ISOLDE short box prototype. To monitor the transverse position of the blade, a series of 0.1 mm diameter holes were drilled on it and their positions were tracked with an optical system. The linear motion actuator was acquired from UHV design (model LSM38-150-SS), and it was adapted to be driven by a brushless EC motor from MAXON. The speed of the scanning blade during the tests was 10 mm/s. The transverse movement of the slit in the direction perpendicular to the movement was lower than 40 m, and is dominated by the displacement of the contact point of the applied force on the lead-screw. An offset on the slit position was observed while changing the direction of movement of the blade, its amplitude being of the order of 30 m. The amplitudes of the displacements...

  20. Scanning slit for HIE-ISOLDE: vibrational test (linear motion actuator from UHV design, speed = 2.5 mm/s)

    CERN Document Server

    Bravin, E; Sosa, A

    2014-01-01

    This report summarizes the results of a series of tests performed on the prototype HIE-ISOLDE diagnostic box (HIE-DB) regarding the vibrations and drifts in the transverse position of the scanning blade while moving inside or outside the box. To monitor the transverse position of the blade, a series of 0.1 mm diameter holes were drilled on it and their positions were tracked with an optical system. The linear motion actuator was acquired from UHV design (model LSM38-150-SS), is driven by a stepper motor and has all the guiding mechanisms outside vacuum. The maximum speed of the scanning blade during the tests was 2.5 mm/s. The transverse movement of the slit in the direction perpendicular to the movement was lower than 50 m, and is dominated by the displacement of the contact point of the applied force on the lead-screw. An offset on the slit position was observed while changing the direction of movement of the blade, its amplitude being of the order of 30 m. The amplitudes of the displacements of the transve...

  1. Vibration isolation performance of an ultra-low frequency folded pendulum resonator

    Science.gov (United States)

    Liu, Jiangfeng; Ju, Li; Blair, David G.

    1997-02-01

    We present an analysis of the transfer function of a very low frequency folded pendulum resonator. It is shown that performance depends critically on centre of percussion tuning of the pendulum arms. Experimental measurements of the transfer function are shown to agree well with theory. The isolator achieves 90 dB isolation at 7 Hz.

  2. Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: AMSU-A2 METSAT Instrument (S/N 108) Acceptance Level Vibration Tests of Dec 1999/Jan 2000 (S/O 784077, OC-454)

    Science.gov (United States)

    Heffner, R.

    2000-01-01

    This is the Engineering Test Report, AMSU-A2 METSAT Instrument (S/N 108) Acceptance Level Vibration Test of Dec 1999/Jan 2000 (S/O 784077, OC-454), for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

  3. Performance Analysis of Wind-Induced Piezoelectric Vibration Bimorph Cantilever for Rotating Machinery

    OpenAIRE

    Gongbo Zhou; Houlian Wang; Zhencai Zhu; Linghua Huang; Wei Li

    2015-01-01

    Harvesting the energy contained in the running environment of rotating machinery would be a good way to supplement energy to the wireless sensor. In this paper, we take piezoelectric bimorph cantilever beam with parallel connection mode as energy collector and analyze the factors which can influence the generation performance. First, a modal response theory model is built. Second, the static analysis, modal analysis, and piezoelectric harmonic response analysis of the wind-induced piezoelectr...

  4. An Appraisal of Frequency of Testing And Students' Performance In ...

    African Journals Online (AJOL)

    An Appraisal of Frequency of Testing And Students' Performance In Junior Secondary School Social Studies Certificate ... The results of the finding revealed a statistical significant difference (using the z-test) in the performances of the students ...

  5. Integrated Performance Testing Workshop - Supplemental Materials (Scripts and Procedures)

    Energy Technology Data Exchange (ETDEWEB)

    Baum, Gregory A.

    2014-02-01

    A variety of performance tests are described relating to: Material Transfers; Emergency Evacuation; Alarm Response Assessment; and an Enhanced Limited Scope Performance Test (ELSPT). Procedures are given for: nuclear material physical inventory and discrepancy; material transfers; and emergency evacuation.

  6. Effect of whole-body vibration on muscle strength, spasticity, and motor performance in spastic diplegic cerebral palsy children

    Directory of Open Access Journals (Sweden)

    Marwa M. Ibrahim

    2014-04-01

    Conclusion: The obtained results suggest that 12-weeks’ intervention of whole-body vibration training can increase knee extensors strength and decrease spasticity with beneficial effects on walking speed and motor development in spastic diplegic CP children.

  7. Linear static structural and vibration analysis on high-performance computers

    Science.gov (United States)

    Baddourah, M. A.; Storaasli, O. O.; Bostic, S. W.

    1993-01-01

    Parallel computers offer the oppurtunity to significantly reduce the computation time necessary to analyze large-scale aerospace structures. This paper presents algorithms developed for and implemented on massively-parallel computers hereafter referred to as Scalable High-Performance Computers (SHPC), for the most computationally intensive tasks involved in structural analysis, namely, generation and assembly of system matrices, solution of systems of equations and calculation of the eigenvalues and eigenvectors. Results on SHPC are presented for large-scale structural problems (i.e. models for High-Speed Civil Transport). The goal of this research is to develop a new, efficient technique which extends structural analysis to SHPC and makes large-scale structural analyses tractable.

  8. Experimental and theoretical investigation of passive damping concepts for member forced and free vibration

    Science.gov (United States)

    Razzaq, Zia; Mykins, David W.

    1987-01-01

    Potential passive damping concepts for use in space structures are identified. The effectiveness of copper brush, wool swab, and silly putty in chamber dampers is investigated through natural vibration tests on a tubular aluminum member. The member ends have zero translation and possess partial rotational restraints. The silly putty in chamber dampers provide the maximum passive damping efficiency. Forced vibration tests are then conducted with one, two, and three damper chambers containing silly putty. Owing to the limitation of the vibrator used, the performance of these dampers could not be evaluated experimentally until the forcing function was disengaged. Nevertheless, their performance is evaluated through a forced dynamic finite element analysis conducted as a part of this investigation. The theoretical results based on experimentally obtained damping ratios indicate that the passive dampers are considerably more effective under member natural vibration than during forced vibration. Also, the maximum damping under forced vibration occurs at or near resonance.

  9. Triazolam - Performance Side Effects: Vestibular, Musculoskeletal, and Complex Performance Tests.

    Science.gov (United States)

    1987-03-04

    performance aff-.ctc of c,•ctain drugs. i.e., alcohol , are amply described in aviation- related literature. Aviation-relevant information on other...Current Therapeutic Research, 21:207-214. 13. Cohn J. B. 1984. Double blind crossover comparison of triazolam and lorazepam in the posthypnotic state...Goodwin D. W., Reichman J. B., Mendelson W. B., and Hopper S. 1982. A comparison of two benzodiazepine hypnotics administered with alcohol . Journal

  10. CHROMagar Salmonella Detection Test Kit. Performance Tested Method 020502.

    Science.gov (United States)

    Webb, Katana; Ritter, Vicki

    2009-01-01

    BBL CHROMagar Salmonella was evaluated by an external food testing laboratory for the recovery of Salmonella in peanut butter using the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA-BAM) procedure. The peanut butter was found to be negative for the presence of Salmonella and, therefore, was seeded with heat-stressed Salmonella at target concentrations of 0.2 and 2 CFU/25 g. The Salmonella-seeded samples remained at room temperature for 14 days before analysis to stabilize the Salmonella in the food environment. Twenty 25 g test portions from each seeded level and five 25 g samples of uninoculated control samples were processed using enrichment broths as outlined in the FDA-BAM procedure. BBL CHROMagar Salmonella-prepared plates were evaluated with the FDA reference method media (bismuth sulfite, xylose lysine desoxycholate, and Hektoen enteric agars). Fractionally positive results were obtained from the lower inoculum level of peanut butter samples. Five positive cultures were recovered from both the BBL CHROMagar Salmonella and reference methods. The two methods gave identical results for all cultures resulting in a method agreement of 100%. McNemar's chi2 test, which assesses the evidence for difference in marginal proportions between two methods, could not be evaluated because it requires one or more discrepant cultures. However, because there were no discrepant cultures, the marginal proportions for the two methods were identical; therefore, there is no evidence of a difference between the methods. This study demonstrates that the results from BBL CHROMagar Salmonella are comparable to the three reference method media for the detection of Salmonella in peanut butter using the FDA-BAM procedures.

  11. Performance evaluation of aluminium test piece against ...

    African Journals Online (AJOL)

    The image quality in diagnostic radiology determines the optimum information about the medical condition of a patient, and the quality is quantified by Modulation Transfer Function (MTF). Catphan700 phantom is a common-ly used phantom to perform MTF measurement on Cone Beam Computed Tomography or ...

  12. Design and Testing of High Performance Brushes.

    Science.gov (United States)

    1982-03-01

    Electric Brushes SARA DILLICH AND DORIS KUHLMANN-WILSDORF Abi Vtcv-The brus resitance of silver graphite (Stackpole SG142, 75 TABLE I wt% All, 25 wt...the performance of Stackpole SG 142 sliding contacts themselves produce (75 w/o Ag, 25 w/o C) silver graphite heat and are thus prone to introduce

  13. Performance Analysis of Wind-Induced Piezoelectric Vibration Bimorph Cantilever for Rotating Machinery

    Directory of Open Access Journals (Sweden)

    Gongbo Zhou

    2015-01-01

    Full Text Available Harvesting the energy contained in the running environment of rotating machinery would be a good way to supplement energy to the wireless sensor. In this paper, we take piezoelectric bimorph cantilever beam with parallel connection mode as energy collector and analyze the factors which can influence the generation performance. First, a modal response theory model is built. Second, the static analysis, modal analysis, and piezoelectric harmonic response analysis of the wind-induced piezoelectric bimorph cantilever beam are given in detail. Finally, an experiment is also conducted. The results show that wind-induced piezoelectric bimorph cantilever beam has low resonant frequency and stable output under the first modal mode and can achieve the maximum output voltage under the resonant condition. The output voltage increases with the increase of the length and width of wind-induced piezoelectric bimorph cantilever beam, but the latter increasing amplitude is relatively smaller. In addition, the output voltage decreases with the increase of the thickness and the ratio of metal substrate to piezoelectric patches thickness. The experiment showed that the voltage amplitude generated by the piezoelectric bimorph cantilever beam can reach the value simulated in ANSYS, which is suitable for actual working conditions.

  14. Hand function tests and questions on hand symptoms as related to the Stockholm workshop scales for diagnosis of hand-arm vibration syndrome.

    Science.gov (United States)

    Cederlund, R; Iwarsson, S; Lundborg, G

    2003-04-01

    The severity of hand-arm vibration syndrome (HAVS) is usually graded according to the Stockholm workshop scales. Although the Stockholm workshop scales are regarded the gold standard for assessing the severity of HAVS, they are based primarily on subjective symptoms. The aim of the present study was to explore the agreement between Stockholm workshop scales and the outcome from ten well-defined clinical tests commonly used in hand rehabilitation for assessment of hand function. One hundred and eleven vibration-exposed workers participated in the study. Ten objective tests of hand function and four questions on subjective hand symptoms were included. The results indicated that, out of these tests, perception of vibration, perception of touch/pressure and dexterity showed a moderate agreement with Stockholm workshop scales. Among specific questions on hand symptoms, cold intolerance and pain showed a high agreement with Stockholm workshop scales. It is concluded that defined objective tests combined with directed questions on specific hand symptoms, together with the Stockholm workshop scales, may be helpful for diagnosing HAVS.

  15. Vision Influence on Whole-Body Human Vibration Comfort Levels

    Directory of Open Access Journals (Sweden)

    Maria Lúcia Machado Duarte

    2006-01-01

    Full Text Available The well being of people needs to be a priority in the modern world. In that respect, vibration cannot be one more cause of stress. Besides that, vibration comfort is very important, since high levels may cause health or even tasks' accomplishment problems. Several parameters may influence the levels of vibration a human being supports. Among them, one can mention the influence of gender, age, corporeal mass index (CMI, temperature, humor, anxiety, hearing, posture, vision, etc. The first three parameters mentioned were already investigated in previous studies undertaken by GRAVI (Group of Acoustics and Vibration researchers. In this paper, the influence of vision is evaluated. The main objective with this series of tests performed is to try to quantify in a future the influence of each parameter in a global vibration comfort level. Conclusions are presented for the parameter investigated.

  16. Researches Concerning to Minimize Vibrations when Processing Normal Lathe

    Directory of Open Access Journals (Sweden)

    Lenuța Cîndea

    2015-09-01

    Full Text Available In the cutting process, vibration is inevitable appearance, and in situations where the amplitude exceeds the limits of precision dimensional and shape of the surfaces generated vibrator phenomenon is detrimental.Field vibration is an issue of increasingly developed, so the futures will a better understanding of them and their use even in other sectors.The paper developed experimental measurement of vibrations at the lathe machining normal. The scheme described kinematical machine tool, cutting tool, cutting conditions, presenting experimental facility for measuring vibration occurring at turning. Experimental results have followed measurement of amplitude, which occurs during interior turning the knife without silencer incorporated. The tests were performed continuously for different speed, feed and depth of cut.

  17. Lessons Learned on the Application of Vibration Absorbers for Enhanced Cannon Stabilization

    Directory of Open Access Journals (Sweden)

    Eric Kathe

    2001-01-01

    Full Text Available This paper will summarize the successful application of muzzle-end vibration absorbers to reduce cannon vibration. This technology constitutes a weapons stabilization approach that focuses on passive mechanical structural modification of the cannon, rather than relying upon an external control law to actively cancel vibrations. Challenges encountered during field testing, non-ideal behavior, and performance evaluation using digital signal processing will be highlighted.

  18. Effect of combining passive muscle stretching and whole body vibration on spasticity and physical performance of children and adolescents with cerebral palsy.

    Science.gov (United States)

    Tupimai, Teeraporn; Peungsuwan, Punnee; Prasertnoo, Jitlada; Yamauchi, Juinichiro

    2016-01-01

    [Purpose] This study evaluated the immediate and short-term effects of a combination of prolonged passive muscle stretching (PMS) and whole body vibration (WBV) on the spasticity, strength and balance of children and adolescents with cerebral palsy. [Subjects and Methods] A randomized two-period crossover trial was designed. Twelve subjects with cerebral palsy aged 10.6 ± 2.4 years received both PMS alone as a control group (CG) and a combination of PMS and WBV as an experimental group (EG). After random allocation to the trial schedules of either EG-CG or CG-EG, CG received prolonged PMS while standing on a tilt-table for 40 minutes/day, and EG received prolonged PMS for 30 minutes, followed by 10 minutes WBV. Both CG and EG received the treatment 5 days/week for 6 weeks. [Results] Immediately after one treatment, EG resulted in better improvement in scores on the Modified Ashworth Scale than CG. After the 6-week intervention, EG also showed significantly decreased scores on the Modified Ashworth Scale compared to CG. Both CG and EG showed significantly reduced the performance times in the five times sit to stand test, and EG also showed significantly increased scores on the pediatric balance scale. [Conclusion] This study showed that 6 weeks of combined prolonged PMS and WBV had beneficial effects on the spasticity, muscle strength and balance of children and adolescents with CP.

  19. The feasibility of whole body vibration in institutionalised elderly persons and its influence on muscle performance, balance and mobility: a randomised controlled trial [ISRCTN62535013

    Directory of Open Access Journals (Sweden)

    Van Hees Ellen

    2005-12-01

    Full Text Available Abstract Background Fatigue or lack of interest can reduce the feasibility of intensive physical exercise in nursing home residents. Low-volume exercise interventions with similar training effects might be an alternative. The aim of this randomised controlled trial was to investigate the feasibility of Whole Body Vibration (WBV in institutionalised elderly, and its impact on functional capacity and muscle performance. Methods Twenty-four nursing home residents (15 female, 9 male; mean age 77.5 ± 11.0 years were randomised (stratification for age, gender and ADL-category to 6 weeks static WBV exercise (WBV+, N = 13 or control (only static exercise; N = 11. Outcome measures were exercise compliance, timed up-and-go, Tinetti-test, back scratch, chair sit-and-reach, handgrip strength and linear isokinetic leg extension. Results At baseline, WBV+ and control groups were similar for all outcome variables. Twenty-one participants completed the program and attended respectively 96% and 86% of the exercise sessions for the WBV+ and control groups. Training-induced changes in timed up-and-go and Tinetti-test were better for WBV+ compared to control (p = 0.029 for timed up-and-go, p = 0.001 and p = 0.002 for Tinetti body balance and total score respectively. In an alternative analysis (Worst Rank Score & Last Observation Carried Forward the differences in change remained significant on the Tinetti body balance and total score. No other significant differences in change between both groups were observed. Conclusion In nursing home residents with limited functional dependency, six weeks static WBV exercise is feasible, and is beneficial for balance and mobility. The supplementary benefit of WBV on muscle performance compared to classic exercise remains to be explored further.

  20. Performance test of PPAC in different gases

    CERN Document Server

    Wang Meng; Zhan Wen Long; Xiao Guo Qing; Xu Hu Shan; Mao Rui Shi; Hu Zheng Guo; Chen Zhi Qiang; Sun Zhi Yu; Li Jia Xing; Wang Wu Sheng; Chen Li Xin; Li Chen; Bai Jie; Zhang Xia; Zhang Jin Xia; Li Cun Fan

    2002-01-01

    A two-dimension position sensitive parallel-plate avalanche (PPAC) detector has been developed for RIBLL. The detector consists of one anode and two cathodes. In each cathode a resistance chain is used to readout position signals. The detector has been tested in different operating gases with an alpha source. When the detector is at 7 mb flowing rate of isobutane and + 500 V on anode, the position resolution of 0.76 mm is obtained. For 7 mb C sub 3 F sub 8 and +595 V on anode, the position resolution is 0.64 mm. The efficiencies are around 99.1% in the cases of C sub 3 F sub 8 and isobutane

  1. Immediate effects after stochastic resonance whole-body vibration on physical performance on frail elderly for skilling-up training: a blind cross-over randomised pilot study.

    Science.gov (United States)

    Rogan, Slavko; Schmidtbleicher, Dietmar; Radlinger, Lorenz

    2014-10-01

    This pilot study examined the feasibility outcome recruitment, safety and compliance of the investigation for stochastic resonance whole-body vibration (SR-WBV) training. Another aim was to evaluate the effect size of one SR-WBV intervention session on Short Physical Performance Battery (SPPB), Expanded Timed Get Up-and-Go (ETGUG), isometric maximal voluntary contraction (IMVC) and rate of force development (IRFD) and chair rising (CR). Randomised double-blinded controlled cross-over pilot study. Feasibility outcomes included recruitment, safety and compliance. For secondary outcomes, SPPB, ETGUG, IMVC, IRFD and CR were measured before and 2-min after intervention. Nonparametric Rank-Order Tests of Puri and Sen L Statistics to Ranked Data were proposed. Wilcoxon signed-ranked tests were used to analyse the differences after SR-WBV intervention and sham intervention. Treatment effects between the interventions were compared by a Mann-Whitney U test. Among 24 eligible frail elderly, 12 agreed to participate and 3 drop out. The adherence was 15 of 24 intervention sessions. For secondary outcome, effect sizes (ES) for SR-WBV intervention on SPPB, ETGUG and CR were determined. This pilot study indicate that the training protocol used in this form for frail elderly individuals is feasible but with modification due to the fact that not all defined feasibility outcomes target was met. SR-WBV with 6 Hz, noise level 4 shows benefit improvements on SPPB (ES 0.52), ETGUG (part sit-to-stand movement: ES 0.81; total time: ES 0.85) and CR (ES 0.66). Further research is desired to determine whether a new adapted training protocol is necessary for SR-WBV in the "skilling up" phase in frail elderly individuals.

  2. Seismic Performance and Ice-Induced Vibration Control of Offshore Platform Structures Based on the ISO-PFD-SMA Brace System

    Directory of Open Access Journals (Sweden)

    Jigang Zhang

    2017-01-01

    Full Text Available Pall-typed frictional damper (PFD has higher capacity of energy dissipation, whereas shape memory alloy (SMA has excellent superelastic performance. Therefore, combining PFD and SMA together as a brace system has a great prospect in vibration control of structures. This paper investigates the performance of offshore platform with three structural configurations including the SMA brace system, the ISO-SMA (where ISO stands for isolation brace system, and the ISO-PFD-SMA brace system, which are subjected to seismic and ice-induced excitations. In this study, PFD-SMA brace system is installed on the isolation layer of jacket platform, which is under earthquake excitations and ice loading. Then, the reduction of vibration is evaluated by using ANSYS program. The results show that the PFD-SMA brace system is useful in reducing the seismic response and ice-induced response of offshore platform structures; meanwhile, it also demonstrates excellent energy dissipation and hysteretic behavior.

  3. Comparison of the performance of different DFT methods in the calculations of the molecular structure and vibration spectra of serotonin (5-hydroxytryptamine, 5-HT)

    Science.gov (United States)

    Yang, Yue; Gao, Hongwei

    2012-04-01

    Serotonin (5-hydroxytryptamine, 5-HT) is a monoamine neurotransmitter which plays an important role in treating acute or clinical stress. The comparative performance of different density functional theory (DFT) methods at various basis sets in predicting the molecular structure and vibration spectra of serotonin was reported. The calculation results of different methods including mPW1PW91, HCTH, SVWN, PBEPBE, B3PW91 and B3LYP with various basis sets including LANL2DZ, SDD, LANL2MB, 6-31G, 6-311++G and 6-311+G* were compared with the experimental data. It is remarkable that the SVWN/6-311++G and SVWN/6-311+G* levels afford the best quality to predict the structure of serotonin. The results also indicate that PBEPBE/LANL2DZ level show better performance in the vibration spectra prediction of serotonin than other DFT methods.

  4. Comparative Performance of Florida Seniors on the GED Test Battery.

    Science.gov (United States)

    Stoker, Howard W.

    1985-01-01

    Two studies investigated the performance of Florida high school seniors on the Tests of General Educational Development (GED Tests). The GED Test Battery, as revised in 1980, consists of 290 items in 5 subject areas (writing, social studies, science, reading, and mathematics). In the first study, the performance of 1,200 Florida students was…

  5. Fenestration System Performance Research, Testing, and Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Jim Benney

    2009-11-30

    The US DOE was and is instrumental to NFRC's beginning and its continued success. The 2005 to 2009 funding enables NFRC to continue expanding and create new, improved ratings procedures. Research funded by the US DOE enables increased fenestration energy rating accuracy. International harmonization efforts supported by the US DOE allow the US to be the global leader in fenestration energy ratings. Many other governments are working with the NFRC to share its experience and knowledge toward development of their own national fenestration rating process similar to the NFRC's. The broad and diverse membership composition of NFRC allows anyone with a fenestration interest to come forward with an idea or improvement to the entire fenestration community for consideration. The NFRC looks forward to the next several years of growth while remaining the nation's resource for fair, accurate, and credible fenestration product energy ratings. NFRC continues to improve its rating system by considering new research, methodologies, and expanding to include new fenestration products. Currently, NFRC is working towards attachment energy ratings. Attachments are blinds, shades, awnings, and overhangs. Attachments may enable a building to achieve significant energy savings. An NFRC rating will enable fair competition, a basis for code references, and a new ENERGY STAR product category. NFRC also is developing rating methods to consider non specular glazing such as fritted glass. Commercial applications frequently use fritted glazing, but no rating method exists. NFRC is testing new software that may enable this new rating and contribute further to energy conservation. Around the world, many nations are seeking new energy conservation methods and NFRC is poised to harmonize its rating system assisting these nations to better manage and conserve energy in buildings by using NFRC rated and labeled fenestration products. As this report has shown, much more work needs to be

  6. Airflow induced vibration of the Si-IT prototype

    CERN Document Server

    Dijkstra, H; De Aguiar, V; Rigo, V

    2014-01-01

    In this note we present the results of air-flow induced vibration tests performed on mechanical prototypes of the Si option of the Inner Tracker upgrade. We made a modal analyze where we observed the eigenfrequency of the Si-ladder structure at ∼30 Hz as previously measured at CERN. Flowing dry-air to cool the prototypes we do not observe a lock-in state of the vortex induced vibration (VIV). The maximum observed vibration amplitude is calculated. We conclude that the VIV excites the eigenfrequency almost independently from the air-flow speed, and with an amplitude which does not damage the structure.

  7. Experimental study on titanium wire drawing with ultrasonic vibration.

    Science.gov (United States)

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

    2018-02-01

    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.

  8. 10 CFR 26.168 - Blind performance testing.

    Science.gov (United States)

    2010-01-01

    ... laboratory; (2) The collector and licensee testing facility personnel, as appropriate, shall use a custody... other entity shall ensure that all blind performance test samples include split samples, when the FFD program includes split specimen procedures. ...

  9. Qualification Plus: Performance and Durability Tests Beyond IEC 61215 (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, S.; Jordan, J.; Kempe, M.; Miller, D.; Bosco, N.; Silverman, T.; Hacke, P.; Phillips, N.; Earnest, T.; Romero, R.

    2014-03-01

    Qualification Plus is an accelerated test protocol and quality management system that gives higher confidence in field performance of PV modules compared with conventional qualification testing. The test sequences are being developed as consensus standards, but the early publication of these tests enables the community to begin benefiting from them sooner.

  10. Calculation and analysis of the harmonic vibrational frequencies in molecules at extreme pressure: Methodology and diborane as a test case

    Science.gov (United States)

    Cammi, R.; Cappelli, C.; Mennucci, B.; Tomasi, J.

    2012-10-01

    We present a new quantum chemical method for the calculation of the equilibrium geometry and the harmonic vibrational frequencies of molecular systems in dense medium at high pressures (of the order of GPa). The new computational method, named PCM-XP, is based on the polarizable continuum model (PCM), amply used for the study of the solvent effects at standard condition of pressure, and it is accompanied by a new method of analysis for the interpretation of the mechanisms underpinning the effects of pressure on the molecular geometries and the harmonic vibrational frequencies. The PCM-XP has been applied at the density functional theory level to diborane as a molecular system under high pressure. The computed harmonic vibrational frequencies as a function of the pressure have shown a satisfactory agreement with the corresponding experimental results, and the parallel application of the method of analysis has reveled that the effects of the pressure on the equilibrium geometry can be interpreted in terms of direct effects on the electronic charge distribution of the molecular solutes, and that the effects on the harmonic vibrational frequencies can be described in terms of two physically distinct effects of the pressure (curvature and relaxation) on the potential energy for the motion of the nuclei.

  11. Motivational and Cognitive Test-Taking Strategies and Their Influence on Test Performance in Mathematics

    Science.gov (United States)

    Peng, Yun; Hong, Eunsook; Mason, Elsa

    2014-01-01

    A structural equation model of relationships among testing-related motivation variables (test value, effort, self-efficacy, and test anxiety), test-taking strategies (test tactics and metacognitive strategies), gender, and math test performance were examined with a sample of 10th graders (N = 438; 182 males and 256 females). In general, motivation…

  12. Chinese College Test Takers' Individual Differences and Reading Test Performance: A Structural Equation Modeling Approach.

    Science.gov (United States)

    Zhang, Limei

    2016-06-01

    This study reports on the relationships between test takers' individual differences and their performance on a reading comprehension test. A total of 518 Chinese college students (252 women and 256 men; M age = 19.26 year, SD = 0.98) answered a questionnaire and sit for a reading comprehension test. The study found that test takers' L2 language proficiency was closely linked to their test performance. Test takers' employment of strategies was significantly and positively associated with their performance on the test. Test takers' motivation was found to be significantly associated with reading test performance. Test anxiety was negatively related to their use of reading strategies and test performance. The results of the study lent support to the threshold hypothesis of language proficiency. The implications for classroom teaching were provided. © The Author(s) 2016.

  13. Study of test script design methods for Web Service performance testing

    Science.gov (United States)

    Xu, Peng

    2017-09-01

    Web Service interface technology is more and more widely applied in information system. And more requirements of Web Service performance testing are demanded. Nevertheless, designing the test script for performance testing is hard to take into practice. In this paper, two kinds of test script design methods for Web Service performance testing are presented by using LoadRunner and SOAP UI tools. That is The Service Call Method and The SOAP Method.

  14. Priming competence diminishes the link between cognitive test anxiety and test performance. Implications for the interpretation of test scores.

    Science.gov (United States)

    Lang, Jonas W B; Lang, Jessica

    2010-06-01

    Researchers disagree whether the correlation between cognitive test anxiety and test performance is causal or explainable by skill deficits, which lead to both cognitive test anxiety and lower test performance. Most causal theories of test anxiety assume that individual differences in cognitive test anxiety originate from differences in self-perceived competence. Accordingly, in the present research, we sought to temporarily heighten perceptions of competence using a priming intervention. Two studies with secondary- and vocational-school students (Ns = 219 and 232, respectively) contrasted this intervention with a no-priming control condition. Priming competence diminished the association between cognitive test anxiety and test performance by heightening the performance of cognitively test-anxious students and by lowering the performance of students with low levels of cognitive test anxiety. The findings suggest that cognitively test-anxious persons have greater abilities than they commonly show. Competency priming may offer a way to improve the situation of people with cognitive test anxiety.

  15. Comparing the Effects of Test Anxiety on Independent and Integrated Speaking Test Performance

    Science.gov (United States)

    Huang, Heng-Tsung Danny; Hung, Shao-Ting Alan

    2013-01-01

    Integrated speaking test tasks (integrated tasks) offer textual and/or aural input for test takers on which to base their subsequent oral responses. This path-analytic study modeled the relationship between test anxiety and the performance of such tasks and explored whether test anxiety would differentially affect the performance of independent…

  16. Shock and vibration effects on performance reliability and mechanical integrity of proton exchange membrane fuel cells: A critical review and discussion

    Science.gov (United States)

    Haji Hosseinloo, Ashkan; Ehteshami, Mohsen Mousavi

    2017-10-01

    Performance reliability and mechanical integrity are the main bottlenecks in mass commercialization of PEMFCs for applications with inherent harsh environment such as automotive and aerospace applications. Imparted shock and vibration to the fuel cell in such applications could bring about numerous issues including clamping torque loosening, gas leakage, increased electrical resistance, and structural damage and breakage. Here, we provide a comprehensive review and critique of the literature focusing on the effects of mechanically harsh environment on PEMFCs, and at the end, we suggest two main future directions in FC technology research that need immediate attention: (i) developing a generic and adequately accurate dynamic model of PEMFCs to assess the dynamic response of FC devices, and (ii) designing effective and robust shock and vibration protection systems based on the developed models in (i).

  17. 49 CFR 178.608 - Vibration standard.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Vibration standard. 178.608 Section 178.608... Testing of Non-bulk Packagings and Packages § 178.608 Vibration standard. (a) Each packaging must be capable of withstanding, without rupture or leakage, the vibration test procedure outlined in this section...

  18. Validation of Functional Performance Tests after Anterior Cruciate Ligament Reconstruction

    Science.gov (United States)

    Kong, Doo Hwan; Yang, Sang Jin; Ha, Jeong Ku; Jang, Seok Hwan; Seo, Jung Gook

    2012-01-01

    Purpose To validate the functional performance tests (FPTs) after anterior cruciate ligament (ACL) reconstruction. Materials and Methods Thirty men in their third decade after ACL reconstruction at 6 month follow-up and thirty healthy subjects were selected. Lysholm knee score, International Knee Documentation Committee (IKDC) subjective score, Tegner activity score, KT-2000 arthrometer test, isokinetic strength test, functional performance tests (one leg hop test, co-contraction test, shuttle run test, carioca test) were performed in two groups. We evaluated the test-retest reliability of FPTs in healthy group and the between FPTs and other parameters in ACL reconstruction group. Results The test-retest result showed high correlation in co-contraction test (r=0.511), shuttle run test (r=0.746), carioca test (r=0.742). In the ACL reconstruction group, the IKDC score, Tegner activity score, extensor power at 60°/s, and one leg hop test also showed high correlation between each test. Conclusions The three FPTs showed correlations with the established methods for determining return to sports activities after ACL reconstruction and had high test-retest reliability. Therefore we believe the three FPTs can be useful methods to assess knee function in athletes after ACL reconstruction. PMID:22570851

  19. The effect of whole body vibration on balance, gait performance and mobility in people with stroke: a systematic review and meta-analysis.

    Science.gov (United States)

    Yang, Xiaotian; Wang, Pu; Liu, Chuan; He, Chengqi; Reinhardt, Jan D

    2015-07-01

    To examine the effect of whole body vibration on balance, gait performance and mobility among people with stroke. A systematic review was conducted by two independent reviewers who completed the article search and selection. We included randomized controlled trials published in English examining effects of whole body vibration on balance, gait, mobility, muscle strength and muscle tone in adults with a clinical diagnosis of stroke. Articles were excluded if they were research studies on people with other primary diagnosis, abstracts published in the conferences or books. The Cochrane risk of bias tool was used to assess the methodological quality of the selected studies. Sources included Cochrane Central Register of Controlled Trials, Pubmed, MEDLINE, CINAHL, EMBASE, PEDro, PsycINFO, Science Citation Index, ClinicalTrials.gov, Current Controlled Trials, Stroke Trials Registry, and reference lists of all relevant articles. Eight randomized controlled trials (nine articles) involving 271 participants were included in this meta-analysis. No significant improvement was found regarding Berg balance scale (SMD=-0.08, 95%CI=-1.35 to 1.19, P=0.91), mobility (SMD=0.45, 95%CI=-0.46 to 1.37, P=0.33), maximal isometric contracion of knee extension strength (SMD=0.23, 95%CI=-0.27 to 0.74, P=0.36), and maximal isometric contracion of knee extension strength (SMD=0.09, 95%CI=-0.38 to 0.56, P=0.71). There was no evidence for effects of whole body vibration on balance in people with stroke. Effects of whole body vibration on mobility and gait performance remain inconclusive. More large and high-quality trials are required. © The Author(s) 2014.

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

    Directory of Open Access Journals (Sweden)

    Shuai Wang

    2017-04-01

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

  1. 40 CFR 63.2354 - What performance tests, design evaluations, and performance evaluations must I conduct?

    Science.gov (United States)

    2010-07-01

    ... evaluations, and performance evaluations must I conduct? 63.2354 Section 63.2354 Protection of Environment... tests, design evaluations, and performance evaluations must I conduct? (a)(1) For each performance test... procedures specified in subpart SS of this part. (3) For each performance evaluation of a continuous emission...

  2. Seeing red? The Effect of Colour on Intelligence Test Performance

    OpenAIRE

    Larsson, Emma; Von Stumm, Sophie

    2015-01-01

    A series of recent studies reported that seeing red was associated with poor intelligence test performance in university students. Here we test for the first time the effect of colour on intelligence test scores in an adult sample and across a large battery of ability tests. Overall 200 British adults completed Raven’s matrices without colour manipulation (i.e. baseline assessment); afterwards, they then either viewed red or green before completing six additional ability tests (i.e. word flue...

  3. Vibrational Diver

    Science.gov (United States)

    Kozlov, Victor; Ivanova, Alevtina; Schipitsyn, Vitalii; Stambouli, Moncef

    2014-10-01

    The paper is concerned with dynamics of light solid in cavity with liquid subjected to rotational vibration in the external force field. New vibrational phenomenon - diving of a light cylinder to the cavity bottom is found. The experimental investigation of a horizontal annulus with a partition has shown that under vibration a light body situated in the upper part of the layer is displaced in a threshold manner some distance away from the boundary. In this case the body executes symmetric tangential oscillations. An increase of the vibration intensity leads to a tangential displacement of the body near the external boundary. This displacement is caused by the tangential component of the vibrational lift force, which appears as soon as the oscillations lose symmetry. In this case the trajectory of the body oscillatory motion has the form of a loop. The tangential lift force makes stable the position of the body on the inclined section of the layer and even in its lower part. A theoretical interpretation has been proposed, which explains stabilization of a quasi-equilibrium state of a light body near the cavity bottom in the framework of vibrational hydromechanics.

  4. Beam test performance of the SKIROC2 ASIC

    Energy Technology Data Exchange (ETDEWEB)

    Amjad, M.S. [Laboratoire de l' Accélérateur Linéaire, Centre Scientifique d' Orsay, Université de Paris-Sud XI, CNRS/IN2P3, F-91898 Orsay Cedex (France); Anduze, M. [Laboratoire Leprince-Ringuet, École Polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Augustin, J.-E. [Laboratoire de Physique Nucléaire et de Hautes Energies, UPMC, Université Paris Diderot, CNRS/IN2P3, Paris (France); Bonis, J. [Laboratoire de l' Accélérateur Linéaire, Centre Scientifique d' Orsay, Université de Paris-Sud XI, CNRS/IN2P3, F-91898 Orsay Cedex (France); Boudry, V. [Laboratoire Leprince-Ringuet, École Polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Bourgeois, C. [Laboratoire de l' Accélérateur Linéaire, Centre Scientifique d' Orsay, Université de Paris-Sud XI, CNRS/IN2P3, F-91898 Orsay Cedex (France); Brient, J.-C. [Laboratoire Leprince-Ringuet, École Polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Callier, S. [OMEGA, École Polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Cerutti, M. [Laboratoire Leprince-Ringuet, École Polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Chen, S. [Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Cornat, R. [Laboratoire Leprince-Ringuet, École Polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); and others

    2015-04-01

    Beam tests of the first layers of CALICE silicon tungsten ECAL technological prototype were performed in April and July 2012 using 1–6 GeV electron beam at DESY. This paper presents an analysis of the SKIROC2 readout ASIC performance under test beam conditions.

  5. Beam test performance of the SKIROC2 ASIC

    CERN Document Server

    Frisson, T; Anduze, M; Augustin, J.E; Bonis, J; Boudry, V; Bourgeois, C; Brient, J.C; Callier, S; Cerutti, M; Chen, S; Cornat, R; Cornebise, P; Cuisy, D; David, J; De la Taille, C; Dulucq, F; Frotin, M; Gastaldi, F; Ghislain, P; Giraud, J; Gonnin, A; Grondin, D; Guliyev, E; Hostachy, J.Y; Jeans, D; Kamiya, Y; Kawagoe, K; Kozakai, C; Lacour, D; Lavergne, L; Lee, S.H; Magniette, F; Ono, H; Poeschl, R; Rouëné, J; Seguin-Moreau, N; Song, H.S; Sudo, Y; Thiebault, A; Tran, H; Ueno, H; Van der Kolk, N; Yoshioka, T

    2015-01-01

    Beam tests of the first layers of CALICE silicon tungsten ECAL technological prototype were performed in April and July 2012 using 1–6 GeV electron beam at DESY. This paper presents an analysis of the SKIROC2 readout ASIC performance under test beam conditions.

  6. Incremental exercise test performance with and without a respiratory ...

    African Journals Online (AJOL)

    Objective. Despite their widespread use in exercise testing, few data are available on the effect of wearing respiratory gas collection (RGC) systems on exercise test performance. Industrial- type mask wear is thought to impair exercise performance through increased respiratory dead space, flow resistance and/or discomfort ...

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

    Directory of Open Access Journals (Sweden)

    Praveen Shenoy K

    2018-01-01

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

  8. Infra-red and vibration tests of hybrid ablative/ceramic matrix technological breadboards for earth re-entry thermal protection systems

    Science.gov (United States)

    Barcena, Jorge; Garmendia, Iñaki; Triantou, Kostoula; Mergia, Konstatina; Perez, Beatriz; Florez, Sonia; Pinaud, Gregory; Bouilly, Jean-Marc; Fischer, Wolfgang P. P.

    2017-05-01

    A new thermal protection system for atmospheric earth re-entry is proposed. This concept combines the advantages of both reusable and ablative materials to establish a new hybrid concept with advanced capabilities. The solution consists of the design and the integration of a dual shield resulting on the overlapping of an external thin ablative layer with a Ceramic Matrix Composite (CMC) thermo-structural core. This low density ablative material covers the relatively small heat peak encountered during re-entry the CMC is not able to bear. On the other hand the big advantage of the CMC based TPS is of great benefit which can deal with the high integral heat for the bigger time period of the re-entry. To verify the solution a whole testing plan is envisaged, which as part of it includes thermal shock test by infra-red heating (heating flux up to 1 MW/m2) and vibration test under launcher conditions (Volna and Ariane 5). Sub-scale tile samples (100×100 mm2) representative of the whole system (dual ablator/ceramic layers, insulation, stand-offs) are specifically designed, assembled and tested (including the integration of thermocouples). Both the thermal and the vibration test are analysed numerically by simulation tools using Finite Element Models. The experimental results are in good agreement with the expected calculated parameters and moreover the solution is qualified according to the specified requirements.

  9. Comparison of interactive video test performance to overall class performance in a biomechanics course.

    Science.gov (United States)

    Bennett, Guinevere S

    2017-12-11

    This study compared interactive video test performance and students' overall class performance. The hypothesis was that there would be a difference in video test performance compared to overall class performance. A total of 30 students participated in the pilot study from a master's level biomechanics course. Students completed four interactive video tests using EduCanon; content of videos included base of support, lever systems, scapulohumeral rhythm, and postural analysis. This content was reviewed with class discussion after completion of the interactive video test. The tests administered counted toward the participation portion of the final student grade. Student performance on the EduCanon interactive video test was compared to overall class grade using a paired t-test. All 30 students completed the 4 EduCanon interactive video tests. Final class grades were greater compared to cumulative EduCanon test performance. There was no difference between performance using interactive video testing compared to students' overall class performance (t[29] = -1.43, p = .16). The results of this study did not support improved student assessment performance with incorporation of interactive video testing in the classroom environment. Continued research into new testing strategies is recommended to identify additional effective testing in the classroom.

  10. DEVELOPING an ENGLISH PERFORMANCE TEST for INCOMING INDONESIAN COLLEGE STUDENTS

    Directory of Open Access Journals (Sweden)

    Bill Glenny Wullur

    2011-07-01

    Full Text Available Abstracts This study constructed, developed and validated an English Performance test as a complementary to an existing placement test in Universitas Klabat, Manado, Indonesia.  It is designed to provide a valid criterion-based measurement within the placement programs of the said university. The study aimed to answer the following questions: (1 What test tasks and items are needed in a performance test based on current language testing theory? (2 Is the performance test valid? (3 Is the scoring of the performance test reliable? (4 Is the performance test practical and predictive? And (5 What are the ratings of the resultant performance test? The steps in developing a performance test involved conducting needs analysis, establishing attributes of good performance test, and constructing test specification based on current language testing theory.  The speech event chosen which would generate language use was applying for financial assistance.  From this speech event, four activities were elicited: (1 writing a letter of inquiry, (2 completing an application form, (3 making an appointment for interview, (4 giving an oral presentation/interview.  These activities represent the four authentic tasks in which the desirable modes/channel of communication, language functions and skills, genre, and topic are integrated. The developed test is divided into four sections corresponding with the elicited tasks: (1 Formal letter, (2 Application form, (3 Making Appointment, and (4 Oral Presentation. The test was validated in several ways: (1 face validation compared the scores of Indonesian studying in the Philippines and in Indonesia, and found that the scores are highly correlated at Spearman ρ = .85.  (2 The content validation relied on the evaluation of expert informants.  The finding shows that the content coverage and relevance of the test is highly satisfactory. (3 The concurrent validation was conducted to the existing placement test and found

  11. Experimental identification of viscous damping in linear vibration

    Science.gov (United States)

    Srikantha Phani, A.; Woodhouse, J.

    2009-01-01

    This paper is concerned with the experimental evaluation of the performance of viscous damping identification methods in linear vibration theory. Both existing and some new methods proposed by the present authors [A.S. Phani, J. Woodhouse, Viscous damping identification in linear vibration, Journal of Sound and Vibration 303 (3-5) (2007) 475-500] are applied to experimental data measured on two test structures: a coupled three cantilever beam with moderate modal overlap and a free-free beam with low modal overlap. The performance of each method is quantified and compared based on three norms and the best methods are identified. The role of complex modes in damping identification from vibration measurements is critically assessed.

  12. Design of a nonlinear torsional vibration absorber

    Science.gov (United States)

    Tahir, Ammaar Bin

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

  13. Towards Smart Buildings Performance Testing as a Service

    DEFF Research Database (Denmark)

    Markoska, Elena; Lazarova-Molnar, Sanja

    2018-01-01

    Energy consumption in buildings accounts for ca. 40% of the world’s total energy consumption, yielding a call for attention to their performance and improvement of their behavior. The concept of performance testing has been developed as an approach to control, potentially lower, and bring awareness...... to buildings’ energy consumption. In this paper we propose a methodology for continuous performance testing of smart buildings as a service. We discuss the automatic discovery and instantiation of performance tests, as well as usage of results for discovery of potential faults and ways to improve buldings...

  14. Energy Finite Element Analysis for Computing the High Frequency Vibration of the Aluminum Testbed Cylinder and Correlating the Results to Test Data

    Science.gov (United States)

    Vlahopoulos, Nickolas

    2005-01-01

    The Energy Finite Element Analysis (EFEA) is a finite element based computational method for high frequency vibration and acoustic analysis. The EFEA solves with finite elements governing differential equations for energy variables. These equations are developed from wave equations. Recently, an EFEA method for computing high frequency vibration of structures either in vacuum or in contact with a dense fluid has been presented. The presence of fluid loading has been considered through added mass and radiation damping. The EFEA developments were validated by comparing EFEA results to solutions obtained by very dense conventional finite element models and solutions from classical techniques such as statistical energy analysis (SEA) and the modal decomposition method for bodies of revolution. EFEA results have also been compared favorably with test data for the vibration and the radiated noise generated by a large scale submersible vehicle. The primary variable in EFEA is defined as the time averaged over a period and space averaged over a wavelength energy density. A joint matrix computed from the power transmission coefficients is utilized for coupling the energy density variables across any discontinuities, such as change of plate thickness, plate/stiffener junctions etc. When considering the high frequency vibration of a periodically stiffened plate or cylinder, the flexural wavelength is smaller than the interval length between two periodic stiffeners, therefore the stiffener stiffness can not be smeared by computing an equivalent rigidity for the plate or cylinder. The periodic stiffeners must be regarded as coupling components between periodic units. In this paper, Periodic Structure (PS) theory is utilized for computing the coupling joint matrix and for accounting for the periodicity characteristics.

  15. Vibration Durability Testing of Nickel Manganese Cobalt Oxide (NMC) Lithium-Ion 18,650 Battery Cells

    OpenAIRE

    Hooper, James Michael; Marco, James; Chouchelamane, Gael H.; Lyness, Christopher

    2016-01-01

    Electric vehicle (EV) manufacturers are employing cylindrical format cells in the construction of the vehicles’ battery systems. There is evidence to suggest that both the academic and industrial communities have evaluated cell degradation due to vibration and other forms of mechanical loading. The primary motivation is often the need to satisfy the minimum requirements for safety certification. However, there is limited research that quantifies the durability of the battery and in particular...

  16. 49 CFR 563.10 - Crash test performance and survivability.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Crash test performance and survivability. 563.10... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.10 Crash test...,” must be recorded in the format specified by § 563.8, exist at the completion of the crash test, and be...

  17. Testing the Performance Characteristics of Manipulating Industrial Robots

    Directory of Open Access Journals (Sweden)

    Darina Kumičáková

    2016-09-01

    Full Text Available The article is aimed at an issue of assessment of performance criteria of manipulating industrial robots with focusing on positioning performance. There are presented: the testing of one-directional pose accuracy and repeatability on Robot Fanuc LR Mate 200iC within the Laboratory of the Department of Automation and Production Systems and processing of the measured data. The laser interferometer Renishaw and digital indicator Mitutoyo Digimatic were used for performing the testing experiments.

  18. Piezoelectric Vibration Damping Study for Rotating Composite Fan Blades

    Science.gov (United States)

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

    2012-01-01

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

  19. Research on Electromagnetic Force Distribution and Vibration Performance of A Novel 10/4 Switched Reluctance Motor

    Science.gov (United States)

    Fu, Ziyu; Wang, Xinyu; Cao, Cheng; Liu, Meng; Wang, Kangxi

    2017-06-01

    Radial electromagnetic force is one of the main reasons causing the vibration and noise of the switched reluctance motor. Based on this, the novel structure of 10/4 pole switched reluctance motor is proposed, which increases the air gap flux and electromagnetic torque by increasing the number of stator poles. In addition, the excitation current of the stator winding is reduced by early turn-off angle. Through the finite element modelling analysis, the results show the superiority of the new type of switched reluctance motor. In the end, the vibration characteristics of the conventional motor and the new motor are compared and analysed, and the effect of the structure of this new type of switched reluctance motor is verified.

  20. Qualification of the JWST MIRI Instrument Using Force Limited Vibration

    Science.gov (United States)

    Sykes, J.; Eccleston, P.; Laine, B.; Ngan, I.; Salvignol, J. C.

    2012-07-01

    The MIRI instrument design was qualified for sine and random environments using force limited testing to limit the dynamic responses of the sensitive optical components and mechanisms while demonstrating adequate margin with regard to the environmental flight conditions. Force limiting was achieved using force transducers located between the interface of the instrument and the shaker adapter during the vibration test. Interface forces for each of the three interface points were measured in three orthogonal axes during the low level sine test and used to compute the overturning moment, while the resulting global interface force was directly measured by combining the signals from three individual interfaces during the high level vibrations such that automatic notching could be applied. The test was performed in the recently upgraded vibration facility of the Rutherford Appleton Laboratory. In order to demonstrate and develop the MIRI flight model test approach and procedures, a pull- through test was carried out using the Structural Model of the instrument which had been previously vibrated in 2005 at a different facility. This early test allowed measurement of the facility behaviour with the test article, exercising the notching and abort functions, and highlighting an issue with the stiffness of the adapter, as well as several other lessons learned. An adapter with additional in-plane stiffness to ensure in-phase movement of the interfaces and correct functioning of the force-limiting system was subsequently designed, manufactured and tested in time for the instrument FM test. The vibration test was executed very smoothly thanks to the lessons learned from the preparatory test and the work carried out by the team in advance of the test in preparing modelling and analysis tools which could be used in quasi-real time during the test campaign. The paper intends to present the force limited vibration notching approach as well as the lessons learned from this test.

  1. The Performance test of Mechanical Sodium Pump with Water Environment

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chungho; Kim, Jong-Man; Ko, Yung Joo; Jeong, Ji-Young; Kim, Jong-Bum [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Ko, Bock Seong; Park, Sang Jun; Lee, Yoon Sang [SAM JIN Industrial Co. LTD., Chunan (Korea, Republic of)

    2015-10-15

    As contrasted with PWR(Pressurized light Water Reactor) using water as a coolant, sodium is used as a coolant in SFR because of its low melting temperature, high thermal conductivity, the high boiling temperature allowing the reactors to operate at ambient pressure, and low neutron absorption cross section which is required to achieve a high neutron flux. But, sodium is violently reactive with water or oxygen like the other alkali metal. So Very strict requirements are demanded to design and fabricate of sodium experimental facilities. Furthermore, performance testing in high temperature sodium environments is more expensive and time consuming and need an extra precautions because operating and maintaining of sodium experimental facilities are very difficult. The present paper describes performance test results of mechanical sodium pump with water which has been performed with some design changes using water test facility in SAM JIN Industrial Co. To compare the hydraulic characteristic of model pump with water and sodium, the performance test of model pump were performed using vender's experimental facility for mechanical sodium pump. To accommodate non-uniform thermal expansion and to secure the operability and the safety, the gap size of some parts of original model pump was modified. Performance tests of modified mechanical sodium pump with water were successfully performed. Water is therefore often selected as a surrogate test fluid because it is not only cheap, easily available and easy to handle but also its important hydraulic properties (density and kinematic viscosity) are very similar to that of the sodium. Normal practice to thoroughly test a design or component before applied or installed in reactor is important to ensure the safety and operability in the sodium-cooled fast reactor (SFR). So, in order to estimate the hydraulic behavior of the PHTS pump of DSFR (600 MWe Demonstraion SFR), the performance tests of the model pump such as performance

  2. Non-dynamometric trunk performance tests: reliability and normative data.

    Science.gov (United States)

    Alaranta, H; Hurri, H; Heliövaara, M; Soukka, A; Harju, R

    1994-12-01

    A sample of 508 male and female white-collar and blue-collar employees aged 35 to 54 years was evaluated clinically to determine the reliability of repetitive sit-ups, repetitive arch-ups, repetitive squatting, and static back endurance tests, to determine the normal values of these tests and to detect determinants for trunk muscle performance. All of the given tests had fairly good or even excellent test-retest reliability. Muscular performance capacity decreased with advancing age, particularly among blue-collar workers. Men showed greater muscle endurance in all the muscle tests, and blue-collar workers lower values in all tests. The repetitive tests, in particular, showed reduced values in those with previous low-back pain. Normative values of back endurance, repetitive squatting, sit-up and arch-up tests for different age, sex and occupational groups are presented.

  3. Performance on a work-simulating firefighter test versus approved laboratory tests for firefighters and applicants.

    Science.gov (United States)

    von Heimburg, Erna; Medbø, Jon Ingulf; Sandsund, Mariann; Reinertsen, Randi Eidsmo

    2013-01-01

    Firefighters must meet minimum physical demands. The Norwegian Labour Inspection Authority (NLIA) has approved a standardised treadmill walking test and 3 simple strength tests for smoke divers. The results of the Trondheim test were compared with those of the NLIA tests taking into account possible effects of age, experience level and gender. Four groups of participants took part in the tests: 19 young experienced firefighters, 24 senior male firefighters and inexperienced applicants, 12 male and 8 female. Oxygen uptake (VO2) at exhaustion rose linearly by the duration of the treadmill test. Time spent on the Trondheim test was closely related to performance time and peak VO2 on the treadmill test. Senior experienced firefighters did not perform better than equally fit young applicants. However, female applicants performed poorer on the Trondheim test than on the treadmill test. Performance on the Trondheim test was not closely related to muscle strength beyond a minimum. CONCLUSION. Firefighters completing the Trondheim test in under 19 min fit the requirements of the NLIA treadmill test. The Trondheim test can be used as an alternative to the NLIA tests for testing aerobic fitness but not for muscular strength. Women's result of the Trondheim test were poorer than the results of the NLIA treadmill test, probably because of their lower body mass.

  4. Menstrual cycle, arousal-induction, and intelligence test performance.

    Science.gov (United States)

    Kumari, V; Corr, P J

    1996-02-01

    Regularly menstruating students (aged 19 to 25 yr.) were tested in the morning under high and low arousal-induction conditions (with time-pressure instructions vs without time-pressure instructions) during either midcycle (n = 16 or menstruation phase (n = 16) to study the interactive effects of menstrual phases and time-pressure stress-induced arousal on intelligence test scores on Raven's Standard Progressive Matrices and Hundal's General Mental Ability Test. A crossover interactive effect of menstrual phase and stress-induced arousal was found on performance of the Hundal test, suggesting that performance of subjects who were tested during the midcycle phase (putatively High Basal Arousal) was impaired under the time-pressure instructions condition (High-induced Arousal) as compared to performance under the without time-pressure instructions condition (Low-induced Arousal), with the reverse pattern of effects being true for subjects who were tested during the menstruation phase. Scores on Hundal's test conform to the Yerkes-Dodson (1908) law which relates arousal to task performance and suggests that the menstrual cycle and performance on the intelligence test was arousal-based. No effects, however, were observed for Raven's Matrices, raising the possibility that task characteristics may mediate the relationship between arousal and performance.

  5. Test anxiety, perfectionism, goal orientation, and academic performance.

    Science.gov (United States)

    Eum, KoUn; Rice, Kenneth G

    2011-03-01

    Dimensions of perfectionism and goal orientation have been reported to have differential relationships with test anxiety. However, the degree of inter-relationship between different dimensions of perfectionism, the 2 × 2 model of goal orientations proposed by Elliot and McGregor, cognitive test anxiety, and academic performance indicators is not known. Based on data from 134 university students, we conducted correlation and regression analyses to test associations between adaptive and maladaptive perfectionism, four types of goal orientations, cognitive test anxiety, and two indicators of academic performance: proximal cognitive performance on a word list recall test and distal academic performance in terms of grade point average. Cognitive test anxiety was inversely associated with both performance indicators, and positively associated with maladaptive perfectionism and avoidance goal orientations. Adaptive and maladaptive perfectionism accounted for significant variance in cognitive test anxiety after controlling for approach and avoidance goal orientations. Overall, nearly 50% of the variance in cognitive test anxiety could be attributed to gender, goal orientations, and perfectionism. Results suggested that students who are highly test anxious are likely to be women who endorse avoidance goal orientations and are maladaptively perfectionistic.

  6. Cognitive fatigue influences students' performance on standardized tests.

    Science.gov (United States)

    Sievertsen, Hans Henrik; Gino, Francesca; Piovesan, Marco

    2016-03-08

    Using test data for all children attending Danish public schools between school years 2009/10 and 2012/13, we examine how the time of the test affects performance. Test time is determined by the weekly class schedule and computer availability at the school. We find that, for every hour later in the day, test performance decreases by 0.9% of an SD (95% CI, 0.7-1.0%). However, a 20- to 30-minute break improves average test performance by 1.7% of an SD (95% CI, 1.2-2.2%). These findings have two important policy implications: First, cognitive fatigue should be taken into consideration when deciding on the length of the school day and the frequency and duration of breaks throughout the day. Second, school accountability systems should control for the influence of external factors on test scores.

  7. Thermodynamic performance testing of the orbiter flash evaporator system

    Science.gov (United States)

    Jaax, J. R.; Melgares, M. A.; Frahm, J. P.

    1980-01-01

    System level testing of the space shuttle orbiter's development flash evaporator system (FES) was performed in a thermal vacuum chamber capable of simulating ambient ascent, orbital, and entry temperature and pressure profiles. The test article included the evaporator assembly, high load and topping exhaust duct and nozzle assemblies, and feedwater supply assembly. Steady state and transient heat load, water pressure/temperature and ambient pressure/temperature profiles were imposed by especially designed supporting test hardware. Testing in 1978 verified evaporator and duct heater thermal design, determined FES performance boundaries, and assessed topping evaporator plume characteristics. Testing in 1979 combined the FES with the other systems in the orbiter active thermal control subsystem (ATCS). The FES met or exceeded all nominal and contingency performance requirements during operation with the integrated ATCS. During both tests stability problems were encountered during steady state operations which resulted in subsequent design changes to the water spray nozzle and valve plate assemblies.

  8. 14 CFR Appendix E to Part 417 - Flight Termination System Testing and Analysis

    Science.gov (United States)

    2010-01-01

    ... level, such as for vibration or temperature, used to satisfy a component test requirement of this... component and that the component is free of any physical defect that could adversely affect performance. A...) Transportation vibration. A transportation vibration test or analysis must demonstrate that a component satisfies...

  9. Functional Performance Testing in Athletes with Functional Ankle Instability

    Science.gov (United States)

    Sharma, Nidhi; Sharma, Archna; Singh Sandhu, Jaspal

    2011-01-01

    Purpose To determine if functional performance deficits are present in athletes with functional ankle instability (FAI) compared to healthy athletes using various functional performance tests. Methods Sixty two athletes (mean age-21.7±1.8years; height-168.2±9.1cm; weight-63.8±11.0kg) participated in this case control study. Athletes were divided into two groups: athletes with FAI (FAI group, n=31) and healthy athletes (Non-FAI group, n=31). The FAI group was further divided into two subgroups: FAI with giving way (FAI-GW), FAI with no giving way (FAI-NGW). Functional performance was assessed with the single-limb hopping test, figure-of-8 hop test, side-hop test, single-limb hurdle test, square hop test and single hop test. Results Significant differences (PFAI and Non-FAI groups; between FAI-GW, FAI-NGW and Non-FAI groups. Additionally, the involved limb performed significantly worse (PFAI-GW group for the above-mentioned FPTs. Conclusion Significant functional performance deficits were observed in the FAI group in all tests except single hop test with greater deficits observed in the FAI-GW group. Hence, these tests can be used to determine the presence of FAI. However no deficits were identified for the test involving sagittal plane functional activities suggesting that this test can not be used as a criterion to discriminate individuals with FAI. It was further ascertained that functional performance was not affected by limb dominance. PMID:22375246

  10. Cognitive Fatigue Influences Students’ Performance on Standardized Tests

    DEFF Research Database (Denmark)

    Sievertsen, Hans Henrik; Gino, Francesca; Piovesan, Marco

    2016-01-01

    We identify one potential source of bias that influences children’s performance on standardized tests and that is predictable based on psychological theory: the time at which students take the test. Using test data for all children attending Danish public schools between school years 2009....../10 and 2012/13, we find that, for every hour later in the day, test scores decrease by 0.9% of an SD. In addition, a 20- to 30-minute break improves average test scores. Time of day affects students’ test performance because, over the course of a regular day, students’ mental resources get taxed. Thus......, as the day wears on, students become increasingly fatigued and consequently more likely to underperform on a standardized test....

  11. Cognitive Fatigue Influences Students’ Performance on Standardized Tests

    DEFF Research Database (Denmark)

    Sievertsen, Hans Henrik; Gino, Francesca; Piovesan, Marco

    2016-01-01

    We identify one potential source of bias that influences children’s performance on standardized tests and that is predictable based on psychological theory: the time at which students take the test. Using test data for all children attending Danish public schools between school years 2009......, as the day wears on, students become increasingly fatigued and consequently more likely to underperform on a standardized test......./10 and 2012/13, we find that, for every hour later in the day, test scores decrease by 0.9% of an SD. In addition, a 20- to 30-minute break improves average test scores. Time of day affects students’ test performance because, over the course of a regular day, students’ mental resources get taxed. Thus...

  12. Embedded performance validity testing in neuropsychological assessment: Potential clinical tools.

    Science.gov (United States)

    Rickards, Tyler A; Cranston, Christopher C; Touradji, Pegah; Bechtold, Kathleen T

    2017-01-31

    The article aims to suggest clinically-useful tools in neuropsychological assessment for efficient use of embedded measures of performance validity. To accomplish this, we integrated available validity-related and statistical research from the literature, consensus statements, and survey-based data from practicing neuropsychologists. We provide recommendations for use of 1) Cutoffs for embedded performance validity tests including Reliable Digit Span, California Verbal Learning Test (Second Edition) Forced Choice Recognition, Rey-Osterrieth Complex Figure Test Combination Score, Wisconsin Card Sorting Test Failure to Maintain Set, and the Finger Tapping Test; 2) Selecting number of performance validity measures to administer in an assessment; and 3) Hypothetical clinical decision-making models for use of performance validity testing in a neuropsychological assessment collectively considering behavior, patient reporting, and data indicating invalid or noncredible performance. Performance validity testing helps inform the clinician about an individual's general approach to tasks: response to failure, task engagement and persistence, compliance with task demands. Data-driven clinical suggestions provide a resource to clinicians and to instigate conversation within the field to make more uniform, testable decisions to further the discussion, and guide future research in this area.

  13. Analysis of the vibration of the vehicle body with the elimination of the influence of tires

    Directory of Open Access Journals (Sweden)

    Łukasz KONIECZNY

    2015-09-01

    Full Text Available The article presented the results of vibration measurements of selected elements of the vehicle during the test vibration carried out on a bench with a harmonic kinematic extortion. The results of research carried out for the car when replacing tire and wheels steel tripod eliminating the influence of elasticity and damping tires. The tests were performed at various values of the shock absorber fluid filling (from 100% to 50% of the shock absorber fluid. For registered vibration acceleration STFT analysis was performed.

  14. Effort, symptom validity testing, performance validity testing and traumatic brain injury

    OpenAIRE

    Bigler, Erin D.

    2014-01-01

    Abstract Background: To understand the neurocognitive effects of brain injury, valid neuropsychological test findings are paramount. Review: This review examines the research on what has been referred to a symptom validity testing (SVT). Above a designated cut-score signifies a ?passing? SVT performance which is likely the best indicator of valid neuropsychological test findings. Likewise, substantially below cut-point performance that nears chance or is at chance signifies invalid test perfo...

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

    Directory of Open Access Journals (Sweden)

    Daniel Zurita-Millán

    2016-01-01

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

  16. 40 CFR 63.1384 - Performance test requirements.

    Science.gov (United States)

    2010-07-01

    ... Standards for Hazardous Air Pollutants for Wool Fiberglass Manufacturing § 63.1384 Performance test..., subject to this subpart, while producing the building insulation with the highest LOI expected to be...

  17. Corrosion performance tests for reinforcing steel in concrete : technical report.

    Science.gov (United States)

    2009-10-01

    The existing test method used to assess the corrosion performance of reinforcing steel embedded in : concrete, mainly ASTM G 109, is labor intensive, time consuming, slow to provide comparative results, : and can be expensive. However, with corrosion...

  18. Round robin performance testing of organic photovoltaic devices

    DEFF Research Database (Denmark)

    Gevorgyan, Suren; Zubillaga, Oihana; de Seoane, José María Vega

    2014-01-01

    This study addresses the issue of poor intercomparability of measurements of organic photovoltaic (OPV) devices among different laboratories. We present a round robin performance testing of novel OPV devices among 16 laboratories, organized within the framework of European Research Infrastructure...

  19. Spatiotemporal analysis of normal and pathological human vocal fold vibrations.

    Science.gov (United States)

    Krausert, Christopher R; Liang, Yufang; Zhang, Yu; Rieves, Adam L; Geurink, Kyle R; Jiang, Jack J

    2012-01-01

    For spatiotemporal analysis to become a relevant clinical tool, it must be applied to human vocal fold vibration. Receiver operating characteristic (ROC) analysis will help assess the ability of spatiotemporal parameters to detect pathological vibration. Spatiotemporal parameters of correlation length and entropy were extracted from high-speed videos of 124 subjects, 67 without vocal fold pathology and 57 with either vocal fold polyps or nodules. Mann-Whitney rank sum tests were performed to compare normal vocal fold vibrations to pathological vibrations, and ROC analysis was used to assess the diagnostic value of spatiotemporal analysis. A statistically significant difference was found between the normal and pathological groups in both correlation length (P nodules and polyps groups in either correlation length (P = .227) or entropy (P = .943). The ROC analysis showed an area under the curve of 0.63 for correlation length and 0.51 for entropy. Although they could not effectively distinguish vibration of vocal folds with nodules from those with polyps, the spatiotemporal parameters correlation length and entropy exhibit the ability to differentiate normal and pathological vocal fold vibration and may represent a diagnostic tool for objectively detecting abnormal vibration in the future, especially in neurological voice disorders and vocal folds without a visible lesion. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Attenuation of cryocooler induced vibration in spaceborne infrared payloads

    Science.gov (United States)

    Veprik, A.; Twitto, A.

    2014-01-01

    Recent advancement of operational responsive space programs calls for a development of compact, reliable, low power and vibration free cryogenic cooling for sophisticated infrared payloads. The refrigeration in a typical closed cycle split Stirling linear cryocooler is achieved by a cyclic compression and expansion of a gaseous working agent due to a synchronized reciprocation of electro-dynamically and pneumatically actuated compressor and expander pistons. Attenuation of the cryocooler induced vibration usually relies on the concept of actively assisted momentum cancellation. In a typical dual-piston compressor this objective is achieved by actively synchronizing the motion of oppositely moving piston assemblies; a typical single-piston expander may be counterbalanced by a motorized counter-balancer. The above approach produces complexity, weight, size, high incurred costs and affects reliability. The authors analyze the case of passive attenuation the vibration export induced by the split Stirling linear cryocooler comprised of inline mounted single-piston compressor and expander. Placement of all the moving components onto a common axis results in a single axis consolidation of vibration export and enables use of single tuned dynamic absorber and low frequency vibration mount. From theoretical analysis and full-scale testing, the performance of such vibration protection arrangement is similar to known systems of active vibration cancellation.

  1. Relationships Between Anaerobic Performance, Field Tests and Game Performance of Sitting Volleyball Players

    OpenAIRE

    Marszalek Jolanta; Molik Bartosz; Gomez Miguel Angel; Skučas Kęstutis; Lencse-Mucha Judit; Rekowski Witold; Pokvytyte Vaida; Rutkowska Izabela; Kaźmierska-Kowalewska Kalina

    2015-01-01

    The aim of this study was to evaluate relationships between anaerobic performance, field tests, game performance and anthropometric variables of sitting volleyball players. Twenty elite Polish sitting volleyball players were tested using the 30 s Wingate Anaerobic Test for arm crank ergometer and participated in six physical field tests. Heights in position to block and to spike, as well as arm reach were measured. Players were observed during the game on the court in terms of effectiveness o...

  2. Primer Stepper Motor Nomenclature, Definition, Performance and Recommended Test Methods

    Science.gov (United States)

    Starin, Scott; Shea, Cutter

    2014-01-01

    There has been an unfortunate lack of standardization of the terms and components of stepper motor performance, requirements definition, application of torque margin and implementation of test methods. This paper will address these inconsistencies and discuss in detail the implications of performance parameters, affects of load inertia, control electronics, operational resonances and recommended test methods. Additionally, this paper will recommend parameters for defining and specifying stepper motor actuators. A useful description of terms as well as consolidated equations and recommended requirements is included.

  3. National Unmanned Aerial System Standardized Performance Testing and Rating (NUSTAR)

    Science.gov (United States)

    Kopardekar, Parimal

    2016-01-01

    The overall objective of the NUSTAR Capability is to offer standardized tests and scenario conditions to assess performance of the UAS. The following are goals of the NU-STAR: 1. Create a prototype standardized tests and scenarios that vehicles can be tested against. 2. Identify key performance parameters of all UAS and their standardized measurement strategy. 3. Develop standardized performance reporting method (e.g., consumer report style) to assist prospective buyers. 4. Identify key performance metrics that could be used by judged towards overall safety of the UAS and operations. 5. If vehicle certification standard is made by a regulatory agency, the performance of individual UAS could be compared against the minimum requirement (e.g., sense and avoid detection time, stopping distance, kinetic energy, etc.).

  4. Adaptive PI control strategy for flat permanent magnet linear synchronous motor vibration suppression

    Science.gov (United States)

    Meng, Fanwei; Liu, Chengying; Li, Zhijun; Wang, Liping

    2013-01-01

    Due to low damping ratio, flat permanent magnet linear synchronous motor's vibration is difficult to be damped and the accuracy is limited. The vibration suppressing results are not good enough in the existing research because only the longitudinal direction vibration is considered while the normal direction vibration is neglected. The parameters of the direct-axis current controller are set to be the same as those of the quadrature-axis current controller commonly. This causes contradiction between signal noise and response. To suppress the vibration, the electromagnetic force model of the flat permanent magnet synchronous linear motor is formulated first. Through the analysis of the effect that direct-axis current noise and quadrature-axis current noise have on both direction vibration, it can be declared that the conclusion that longitudinal direction vibration is only related to the quadrature-axis current noise while the normal direction vibration is related to both the quadrature-axis current noise and direct-axis current noise. Then, the simulation test on current loop with a low-pass filter is conducted and the results show that the low-pass filter can not suppress the vibration but makes the vibration more severe. So a vibration suppressing strategy that the proportional gain of direct-axis current controller adapted according to quadrature-axis reference current is proposed. This control strategy can suppress motor vibration by suppressing direct-axis current noise. The experiments results about the effect of K p and T i on normal direction vibration, longitudinal vibration and the position step response show that this strategy suppresses vibration effectively while the motor's motion performance is not affected. The maximum reduction of vibration can be up to 40%. In addition, current test under rated load condition is also conducted and the results show that the control strategy can avoid the conflict between the direct-axis current and the quadrature

  5. Effects of Reference Performance Testing During Aging Using Commercial Cells

    Energy Technology Data Exchange (ETDEWEB)

    Jon P. Christophersen; Chinh D. Ho; David Howell

    2005-07-01

    The Advanced Technology Development Program, under the oversight of the U.S. Department of Energy’s FreedomCAR and Vehicle Technologies Program, is investigating lithium-ion batteries for hybrid-electric vehicle applications. Cells are aged under various test conditions, including temperatures and states-of-charge. Life testing is interrupted at regular intervals to conduct reference performance tests (RPTs), which are used to measure changes in the electrical performance of the cells and then to determine cell degradation as a function of test time. Although designed to be unobtrusive, data from the Advanced Technology Development Gen 2 cells indicated that RPTs actually contributed to cell degradation and failure. A study was performed at the Idaho National Laboratory using commercially available lithium-ion cells to determine the impact of RPTs on life. A series of partial RPTs were performed at regular intervals during life testing and compared to a control group that was life tested without RPT interruption. It was determined that certain components of the RPT were detrimental, while others appeared to improve cell performance. Consequently, a new "mini" RPT was designed as an unobtrusive alternative. Initial testing with commercial cells indicates that the impact of the mini RPT is significantly less than the Gen 2 cell RPT.

  6. Shunted Piezoelectric Vibration Damping Analysis Including Centrifugal Loading Effects

    Science.gov (United States)

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

    2011-01-01

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

  7. Pavement Subgrade Performance Study in the Danish Road Testing Machine

    DEFF Research Database (Denmark)

    Ullidtz, Per; Ertman Larsen, Hans Jørgen

    1997-01-01

    Most existing pavement subgrade criteria are based on the AASHO Road Test, where only one material was tested and for only one climatic condition. To study the validity of these criteria and to refine the criteria a co-operative research program entitled the "International Pavement Subgrade...... Performance Study" was sponsored by the FHWA with American, Finnish and Danish partners. This paper describes the first test series which was carried out in the Danish Road Testing Machine (RTM).The first step in this program is a full scale test on an instrumented pavement in the Danish Road Testing Machine...... deformation of the pavement surface. A simple model describing the plastic strain has been developed.The test showed that currently used subgrade strain criteria are conservative if used with the measured strains in the subgrade. If used with strains calculated from FWD tests using linear elastic theory...

  8. Current Status and Performance Tests of Korea Heat Load Test Facility KoHLT-EB

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sukkwon; Jin, Hyunggon; Shin, Kyuin; Choi, Boguen; Lee, Eohwak; Yoon, Jaesung; Lee, Dongwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Duckhoi; Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    A commissioning test has been scheduled to establish the installation and preliminary performance experiments of the copper hypervapotron mockups. And a qualification test will be performed to evaluate the CuCrZr duct liner in the ITER neutral beam injection facility and the ITER first wall small-scale mockups of the semi-prototype, at up to 1.5 and 5 MW/m{sup 2} high heat flux. Also, this system will be used to test other PFCs for ITER and materials for tokamak reactors. Korean high heat flux test facility(KoHLT-EB; Korea Heat Load Test facility - Electron Beam) by using an electron beam system has been constructed in KAERI to perform the qualification test for ITER blanket FW semi-prototype mockups, hypervapotron cooling devices in fusion devices, and other ITER plasma facing components. The commissioning and performance tests with the supplier of e-gun system have been performed on November 2012. The high heat flux test for hypervapotron cooling device and calorimetry were performed to measure the surface heat flux, the temperature profile and cooling performance. Korean high heat flux test facility for the plasma facing components of nuclear fusion machines will be constructed to evaluate the performance of each component. This facility for the plasma facing materials will be equipped with an electron beam system with a 60 kV acceleration gun.

  9. 42 CFR 84.103 - Man tests; performance requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Man tests; performance requirements. 84.103 Section 84.103 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.103 Man tests;...

  10. Integrated Test Scoring, Performance Rating and Assessment Records Keeping.

    Science.gov (United States)

    Cason, Gerald J.; And Others

    The Objective Test Scoring and Performance Rating (OTS-PR) system is a fully integrated set of 70 modular FORTRAN programs run on a VAX-8530 computer. Even with no knowledge of computers, the user can implement OTS-PR to score multiple-choice tests, include scores from external sources such as hand-scored essays or scores from nationally…

  11. 15 CFR 996.21 - Performance of compliance testing.

    Science.gov (United States)

    2010-01-01

    ... CERTIFICATION REQUIREMENTS FOR NOAA HYDROGRAPHIC PRODUCTS AND SERVICES QUALITY ASSURANCE AND CERTIFICATION REQUIREMENTS FOR NOAA HYDROGRAPHIC PRODUCTS AND SERVICES Certification of a Hydrographic Product and...'s hydrographic product to the testing body for performance of the compliance tests. That body shall...

  12. Precision measurements and test of molecular theory in highly-excited vibrational states of H$_2$ $(v=11)$

    CERN Document Server

    Trivikram, T Madhu; Wcisło, P; Ubachs, W; Salumbides, E J

    2016-01-01

    Accurate $EF{}^1\\Sigma^+_g-X{}^1\\Sigma^+_g$ transition energies in molecular hydrogen were determined for transitions originating from levels with highly-excited vibrational quantum number, $v=11$, in the ground electronic state. Doppler-free two-photon spectroscopy was applied on vibrationally excited H$_2^*$, produced via the photodissociation of H$_2$S, yielding transition frequencies with accuracies of $45$ MHz or $0.0015$ cm$^{-1}$. An important improvement is the enhanced detection efficiency by resonant excitation to autoionizing $7p\\pi$ electronic Rydberg states, resulting in narrow transitions due to reduced ac-Stark effects. Using known $EF$ level energies, the level energies of $X(v=11, J=1,3-5)$ states are derived with accuracies of typically 0.002 cm$^{-1}$. These experimental values are in excellent agreement with, and are more accurate than the results obtained from the most advanced ab initio molecular theory calculations including relativistic and QED contributions.

  13. Performances on Symbol Digit Modalities Test, Color Trails Test, and modified Stroop test in a healthy, elderly Danish sample

    DEFF Research Database (Denmark)

    Vogel, Asmus; Stokholm, Jette; Jørgensen, Kasper

    2013-01-01

    for different age groups. For SDMT and CTT1, Danish Adult Reading Test (DART) score also had a significant impact on test performances. The incongruent version of the modified Stroop test was significantly correlated to education. Moderate and significant correlations were found between the three tests. Even...

  14. Man-Induced Vibrations

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Hansen, Lars Pilegaard

    1994-01-01

    concerned with spectator-induced vertical vibrations on grandstands. The idea is to use impulse response analysis and base the load description on the load impulse. If the method is feasable, it could be used in connection with the formulation of requirements in building codes. During the last two decades...... 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...

  15. Vibration Sensitive Keystroke Analysis

    NARCIS (Netherlands)

    Lopatka, M.; Peetz, M.-H.; van Erp, M.; Stehouwer, H.; van Zaanen, M.

    2009-01-01

    We present a novel method for performing non-invasive biometric analysis on habitual keystroke patterns using a vibration-based feature space. With the increasing availability of 3-D accelerometer chips in laptop computers, conventional methods using time vectors may be augmented using a distinct

  16. Effects of Vigorous Intensity Physical Activity on Mathematics Test Performance

    Science.gov (United States)

    Phillips, David S.; Hannon, James C.; Castelli, Darla M.

    2015-01-01

    The effect of an acute bout of physical activity on academic performance in school-based settings is under researched. The purpose of this study was to examine associations between a single, vigorous (70-85%) bout of physical activity completed during physical education on standardized mathematics test performance among 72, eighth grade students…

  17. Performance test of a dual-purpose disc agrochemical applicator ...

    African Journals Online (AJOL)

    The performance test of a dual-purpose disc agrochemical applicator for field crop was conducted with view to assess the distribution patterns/droplet sizes and uniformity of spreading and or spraying for the agrochemical application. The equipment performances for both granular and liquid chemical application were ...

  18. Tests for predicting endurance kayak performance | Olivier | South ...

    African Journals Online (AJOL)

    Objectives : Previous studies investigating factors contributing to kayak performance have employed sophisticated physiological measures, and the use of specialised dynamometers, to simulate the kayak stroke. Such measures do not have general utility, and the aim of this study was to identify tests that could be performed ...

  19. Performance test of Parabolic Trough Solar Cooker for indoor cooking

    African Journals Online (AJOL)

    Fuel-wood scarcity is a growing problem that has so far been poorly addressed. Solar cooking is one possible solution but its acceptance has been limited partially due to low performance and convenience of use of most of the solar cookers that currently are available. The objective of this research is to test the performance ...

  20. Laboratory Performance Testing of Residential Window Air Conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, J.; Booten, C.; Christensen, D.; Tomerlin, J.

    2013-03-01

    Window air conditioners are the dominant cooling product for residences, in terms of annual unit sales. They are inexpensive, portable and can be installed by the owner. For this reason, they are an attractive solution for supplemental cooling, for retrofitting air conditioning into a home which lacks ductwork, and for renters. Window air conditioners for sale in the United States are required to meet very modest minimum efficiency standards. Four window air conditioners' performance were tested in the Advanced HVAC Systems Laboratory on NREL's campus in Golden, CO. In order to separate and study the refrigerant system's performance, the unit's internal leakage pathways, the unit's fanforced ventilation, and the leakage around the unit resulting from installation in a window, a series of tests were devised that focused on each aspect of the unit's performance. These tests were designed to develop a detailed performance map to determine whole-house performance in different climates. Even though the test regimen deviated thoroughly from the industry-standard ratings test, the results permit simple calculation of an estimated rating for both capacity and efficiency that would result from a standard ratings test. Using this calculation method, it was found that the three new air conditioners' measured performance was consistent with their ratings. This method also permits calculation of equivalent SEER for the test articles. Performance datasets were developed across a broad range of indoor and outdoor operating conditions, and used them to generate performance maps.

  1. Engine performance testing using variable RON95 fuel brands available in Malaysia

    Directory of Open Access Journals (Sweden)

    Mohd Riduan Aizuddin Fahmi

    2017-01-01

    Full Text Available There are various gasoline fuel producers available in Malaysia. The effects of fuel variations from different manufacturers on vehicle performance have always been a debate among users and currently the facts still remains inconclusive. Hence, this study focuses on analyzing various RON95 fuel brands available in the Malaysian market and finding the differences towards engine performance. In terms of engine output, the important data of power (hp and torque (Nm will be gathered by using an engine dynamometer. Another data that would also be taken into account is the knocking where the relative knock index can be measured in percentage using the knock sensor accelerometer. Results have shown that the performance of different fuel brands tested are indeed different albeit by only a small margin even though all fuels are categorized with the same octane rating. The power and torque results also imply that both are influenced by the amount of vibration generated due to engine knocking. Based from the overall outcome, consumers would not need to only focus on a certain type of gasoline brand as all differentiates the engine performance marginally.

  2. Motivational deficits and cognitive test performance in schizophrenia.

    Science.gov (United States)

    Fervaha, Gagan; Zakzanis, Konstantine K; Foussias, George; Graff-Guerrero, Ariel; Agid, Ofer; Remington, Gary

    2014-09-01

    Motivational and cognitive deficits are core features of schizophrenia, both closely linked with functional outcomes. Although poor effort and decreased motivation are known to affect performance on cognitive tests, the extent of this relationship is unclear in patients with schizophrenia. To evaluate the association between intrinsic motivation and cognitive test performance in patients with schizophrenia. Cross-sectional and 6-month prospective follow-up study performed at 57 sites in the United States, including academic and community medical treatment centers, participating in the Clinical Antipsychotic Trials of Intervention Effectiveness study. The primary sample included 431 stable patients with a DSM-IV diagnosis of schizophrenia currently receiving a stable medication regimen. Cognitive performance and intrinsic motivation were evaluated using a comprehensive neuropsychological test battery and a derived measure from the Heinrichs-Carpenter Quality of Life Scale, respectively. Symptom severity and functional status were also assessed. The primary outcome variable was global neurocognition. Individual domains of cognition were also evaluated for their association with motivation. Level of intrinsic motivation was significantly and positively correlated with global cognitive test performance, a relationship that held for each domain of cognition evaluated (correlation range, 0.20-0.34; P motivation and cognitive performance also remained significant after controlling for antipsychotic dose (P motivation during the 6-month follow-up was also found to be significantly related to improvement in global cognitive performance (P motivation and cognitive performance and suggest that test performance is not purely a measure of ability. Future studies assessing cognition in patients with schizophrenia should consider potential moderating variables such as effort and motivation. Implications for the assessment and interpretation of cognitive impairment based on

  3. Vibrating minds

    CERN Document Server

    2009-01-01

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

  4. Spent nuclear fuel storage -- Performance tests and demonstrations

    Energy Technology Data Exchange (ETDEWEB)

    McKinnon, M.A.; DeLoach, V.A.

    1993-04-01

    This report summarizes the results of heat transfer and shielding performance tests and demonstrations conducted from 1983 through 1992 by or in cooperation with the US Department of Energy (DOE), Office of Commercial Radioactive Waste Management (OCRWM). The performance tests consisted of 6 to 14 runs involving one or two loadings, usually three backfill environments (helium, nitrogen, and vacuum backfills), and one or two storage system orientations. A description of the test plan, spent fuel load patterns, results from temperature and dose rate measurements, and fuel integrity evaluations are contained within the report.

  5. Testing Game-Based Performance in Team-Handball.

    Science.gov (United States)

    Wagner, Herbert; Orwat, Matthias; Hinz, Matthias; Pfusterschmied, Jürgen; Bacharach, David W; von Duvillard, Serge P; Müller, Erich

    2016-10-01

    Wagner, H, Orwat, M, Hinz, M, Pfusterschmied, J, Bacharach, DW, von Duvillard, SP, and Müller, E. Testing game-based performance in team-handball. J Strength Cond Res 30(10): 2794-2801, 2016-Team-handball is a fast paced game of defensive and offensive action that includes specific movements of jumping, passing, throwing, checking, and screening. To date and to the best of our knowledge, a game-based performance test (GBPT) for team-handball does not exist. Therefore, the aim of this study was to develop and validate such a test. Seventeen experienced team-handball players performed 2 GBPTs separated by 7 days between each test, an incremental treadmill running test, and a team-handball test game (TG) (2 × 20 minutes). Peak oxygen uptake (V[Combining Dot Above]O2peak), blood lactate concentration (BLC), heart rate (HR), sprinting time, time of offensive and defensive actions as well as running intensities, ball velocity, and jump height were measured in the game-based test. Reliability of the tests was calculated using an intraclass correlation coefficient (ICC). Additionally, we measured V[Combining Dot Above]O2peak in the incremental treadmill running test and BLC, HR, and running intensities in the team-handball TG to determine the validity of the GBPT. For the test-retest reliability, we found an ICC >0.70 for the peak BLC and HR, mean offense and defense time, as well as ball velocity that yielded an ICC >0.90 for the V[Combining Dot Above]O2peak in the GBPT. Percent walking and standing constituted 73% of total time. Moderate (18%) and high (9%) intensity running in the GBPT was similar to the team-handball TG. Our results indicated that the GBPT is a valid and reliable test to analyze team-handball performance (physiological and biomechanical variables) under conditions similar to competition.

  6. Correlation Between Screening Mammography Interpretive Performance on a Test Set and Performance in Clinical Practice.

    Science.gov (United States)

    Miglioretti, Diana L; Ichikawa, Laura; Smith, Robert A; Buist, Diana S M; Carney, Patricia A; Geller, Berta; Monsees, Barbara; Onega, Tracy; Rosenberg, Robert; Sickles, Edward A; Yankaskas, Bonnie C; Kerlikowske, Karla

    2017-10-01

    Evidence is inconsistent about whether radiologists' interpretive performance on a screening mammography test set reflects their performance in clinical practice. This study aimed to estimate the correlation between test set and clinical performance and determine if the correlation is influenced by cancer prevalence or lesion difficulty in the test set. This institutional review board-approved study randomized 83 radiologists from six Breast Cancer Surveillance Consortium registries to assess one of four test sets of 109 screening mammograms each; 48 radiologists completed a fifth test set of 110 mammograms 2 years later. Test sets differed in number of cancer cases and difficulty of lesion detection. Test set sensitivity and specificity were estimated using woman-level and breast-level recall with cancer status and expert opinion as gold standards. Clinical performance was estimated using women-level recall with cancer status as the gold standard. Spearman rank correlations between test set and clinical performance with 95% confidence intervals (CI) were estimated. For test sets with fewer cancers (N = 15) that were more difficult to detect, correlations were weak to moderate for sensitivity (woman level = 0.46, 95% CI = 0.16, 0.69; breast level = 0.35, 95% CI = 0.03, 0.61) and weak for specificity (0.24, 95% CI = 0.01, 0.45) relative to expert recall. Correlations for test sets with more cancers (N = 30) were close to 0 and not statistically significant. Correlations between screening performance on a test set and performance in clinical practice are not strong. Test set performance more accurately reflects performance in clinical practice if cancer prevalence is low and lesions are challenging to detect. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  7. Which significance test performs the best in climate simulations?

    Science.gov (United States)

    Decremer, D.; Chung, C. E.; Ekman, A. M.

    2013-12-01

    Externally-forced climate change simulated by general circulation models (GCMs) needs to be compared with model noise (model internal variability) in order to assess the robustness of climate change signals. Significance tests are performed to establish the robustness of the signal. Student's t-test has been the most popular significance testing technique, despite more sophisticated techniques developed over the years. These sophisticated techniques were designed to address unrealistic assumptions in Student's t-test, such as assuming no temporal correlation in the time series. Some of these advanced techniques were tested before, but only on artificial data generated by time series models that cannot fully capture all the features of GCM output. We evaluate five different significance testing techniques (including Student's t-test) on 10 to 100 continuous-year simulations, and validate the performance using much longer (375 to 1000 years) model simulations. We find that Student's t-test is at least as good as the 4 advanced techniques in estimating model noise for GCM simulations of up to 60 years. Furthermore, in establishing the robustness of signals against noise, Student's t-test is at least as good as the other 4 techniques for the simulations of at least up to 100 years. 10~100 year simulation covers the range of typical model integrations, and over this range we suggest that Student's t-test suffice.

  8. Pharmacists performing quality spirometry testing: an evidence based review.

    Science.gov (United States)

    Cawley, Michael J; Warning, William J

    2015-10-01

    The scope of pharmacist services for patients with pulmonary disease has primarily focused on drug related outcomes; however pharmacists have the ability to broaden the scope of clinical services by performing diagnostic testing including quality spirometry testing. Studies have demonstrated that pharmacists can perform quality spirometry testing based upon international guidelines. The primary aim of this review was to assess the published evidence of pharmacists performing quality spirometry testing based upon American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines. In order to accomplish this, the description of evidence and type of outcome from these services were reviewed. A literature search was conducted using five databases [PubMed (1946-January 2015), International Pharmaceutical Abstracts (1970 to January 2015), Cumulative Index of Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews] with search terms including pharmacy, spirometry, pulmonary function, asthma or COPD was conducted. Searches were limited to publications in English and reported in humans. In addition, Uniform Resource Locators and Google Scholar searches were implemented to include any additional supplemental information. Eight studies (six prospective multi-center trials, two retrospective single center studies) were included. Pharmacists in all studies received specialized training in performing spirometry testing. Of the eight studies meeting inclusion and exclusion criteria, 8 (100%) demonstrated acceptable repeatability of spirometry testing based upon standards set by the ATS/ERS guidelines. Acceptable repeatability of seven studies ranged from 70 to 99% consistent with published data. Available evidence suggests that quality spirometry testing can be performed by pharmacists. More prospective studies are needed to add to the current evidence of quality spirometry testing performed by

  9. Listening strategy use, test anxiety and test performance of intermediate and advanced Iranian EFL learners

    Directory of Open Access Journals (Sweden)

    Raoof Hamzavi

    2014-08-01

    Full Text Available Learning a foreign language has been related with some kind of strategic knowledge on the one hand, and some level of (test-taking apprehension or tension on the other hand, although a small amount of anxiety is normally expected as a natural warning symptom. The current study aimed at investigating the relationship between listening strategy use, test anxiety, and listening test performance of Iranian intermediate and advanced EFL learners. To this end, eighty (40 intermediate and 40 advanced Iranian EFL learners took part in the study by completing Lee’s (1997 Listening Comprehension Strategy Questionnaire, Sarason’s (1975 Test Anxiety Scale (TAS, and two monologues of Listening test performance selected from Listening part of TOEFL. The results of Pearson product moment correlation analyses revealed a significant negative correlation between test anxiety and listening test performance, but a significant positive association between listening strategy use and listening test performance. Furthermore, the results of multiple regression analyses indicated listening strategy use was a stronger predictor of listening test performance. Additionally, the results of independent samples t-test showed a significant difference between Iranian intermediate and advanced EFL learners regarding both their listening strategy use and level of test anxiety.

  10. Double-shell tank integrity assessments ultrasonic test equipment performance test

    Energy Technology Data Exchange (ETDEWEB)

    Pfluger, D.C.

    1996-09-26

    A double-shell tank (DST) inspection (DSTI) system was performance tested over three months until August 1995 at Pittsburgh, Pennsylvania, completing a contract initiated in February 1993 to design, fabricate, and test an ultrasonic inspection system intended to provide ultrasonic test (UT) and visual data to determine the integrity of 28 DSTs at Hanford. The DSTs are approximately one-million-gallon underground radioactive-waste storage tanks. The test was performed in accordance with a procedure (Jensen 1995) that included requirements described in the contract specification (Pfluger 1995). This report documents the results of tests conducted to evaluate the performance of the DSTI system against the requirements of the contract specification. The test of the DSTI system also reflects the performance of qualified personnel and operating procedures.

  11. Sensing Performance Analysis on Quartz Tuning Fork-Probe at the High Order Vibration Mode for Multi-Frequency Scanning Probe Microscopy

    Directory of Open Access Journals (Sweden)

    Xiaofei Zhang

    2018-01-01

    Full Text Available Multi-frequency scanning near-field optical microscopy, based on a quartz tuning fork-probe (QTF-p sensor using the first two orders of in-plane bending symmetrical vibration modes, has recently been developed. This method can simultaneously achieve positional feedback (based on the 1st in-plane mode called the low mode and detect near-field optically induced forces (based on the 2nd in-plane mode called the high mode. Particularly, the high mode sensing performance of the QTF-p is an important issue for characterizing the tip-sample interactions and achieving higher resolution microscopic imaging but the related researches are insufficient. Here, we investigate the vibration performance of QTF-p at high mode based on the experiment and finite element method. The frequency spectrum characteristics are obtained by our homemade laser Doppler vibrometer system. The effects of the properties of the connecting glue layer and the probe features on the dynamic response of the QTF-p sensor at the high mode are investigated for optimization design. Finally, compared with the low mode, an obvious improvement of quality factor, of almost 50%, is obtained at the high mode. Meanwhile, the QTF-p sensor has a high force sensing sensitivity and a large sensing range at the high mode, indicating a broad application prospect for force sensing.

  12. Sensing Performance Analysis on Quartz Tuning Fork-Probe at the High Order Vibration Mode for Multi-Frequency Scanning Probe Microscopy.

    Science.gov (United States)

    Zhang, Xiaofei; Gao, Fengli; Li, Xide

    2018-01-24

    Multi-frequency scanning near-field optical microscopy, based on a quartz tuning fork-probe (QTF-p) sensor using the first two orders of in-plane bending symmetrical vibration modes, has recently been developed. This method can simultaneously achieve positional feedback (based on the 1st in-plane mode called the low mode) and detect near-field optically induced forces (based on the 2nd in-plane mode called the high mode). Particularly, the high mode sensing performance of the QTF-p is an important issue for characterizing the tip-sample interactions and achieving higher resolution microscopic imaging but the related researches are insufficient. Here, we investigate the vibration performance of QTF-p at high mode based on the experiment and finite element method. The frequency spectrum characteristics are obtained by our homemade laser Doppler vibrometer system. The effects of the properties of the connecting glue layer and the probe features on the dynamic response of the QTF-p sensor at the high mode are investigated for optimization design. Finally, compared with the low mode, an obvious improvement of quality factor, of almost 50%, is obtained at the high mode. Meanwhile, the QTF-p sensor has a high force sensing sensitivity and a large sensing range at the high mode, indicating a broad application prospect for force sensing.

  13. Performance and durability testing of parabolic trough receivers

    Science.gov (United States)

    Lei, Dongqiang; Fu, Xuqiang; Zhao, Dongming; Yuan, Guofeng; Wang, Zhifeng; Guo, Minghuan

    2017-06-01

    The paper describes the key performance and durability testing facilities of the parabolic trough receiver developed by Institute of Electrical Engineering, Chinese Academy of Sciences. The indoor heat loss test can be applied at 4-7 different temperature levels within 200-550 on receivers. The optical efficiency test bench consists of 12 metal halide lamps as the solar simulator and a 5 m length half-elliptical cylinder reflector with flat end reflectors. 3 ultra-precision temperature sensors are used in receiver each end to get the temperature difference. The residual gas analysis test bench is applied to analyze and predict the vacuum lifetime of the receiver. It can test the variations of composition and partial pressure of residual gases with temperature and time in the receiver annulus space by a high sensitivity quadrupole mass spectrometer gas analyzer. A coating accelerated ageing test bench, which is also used to test the thermal cycle, has been developed. This test bench uses the absorber tube of the recevier as the resistance heater to heat up the whole receiver. The coating lifetime can be predicted by the Arrhenius parameters. For the cycling test, the compressed air is used to directly cool the inner surface of the absorber tube. The thermal cycling test is performed with temperature cycles from 150 °C to 450 °C for 160 cycles. The maximum thermal cycling frequency is 8 cycles per day. The mechanical fatigue test bench is used to test the bellows and the glass-to-metal seals durability at the same time. Both bellows are expanded and compressed to 6.5 mm in turn with 10,000 cycles. A new rotating test bench was also developed to test the thermal efficiency of the receiver.

  14. The Effects of Testing Accommodations on Students' Performances and Reactions to Testing

    Science.gov (United States)

    Lang, Sylvia C.; Elliott, Stephen N.; Bolt, Daniel M.; Kratochwill, Thomas R.

    2008-01-01

    This study examined the effects of testing accommodations on students' test performances and reactions to the use of testing accommodations. Participants (N = 170) were fourth- and eighth-grade students, with and without disabilities. All students were administered, with and without accommodations, equivalent forms of widely used math and reading…

  15. Effects of Computer-Based Test Administrations on Test Anxiety and Performance.

    Science.gov (United States)

    Shermis, Mark D.; Lombard, Danielle

    1998-01-01

    Examines the degree to which computer and test anxiety have a predictive role in performance across three computer-administered placement tests. Subjects (72 undergraduate students) were measured with the Computer Anxiety Rating Scale, the Test Anxiety Inventory, and the Myers-Briggs Type Indicator. Results suggest that much of what is considered…

  16. Does Test Item Performance Increase with Test-to-Standards Alignment?

    Science.gov (United States)

    Traynor, Anne

    2017-01-01

    Variation in test performance among examinees from different regions or national jurisdictions is often partially attributed to differences in the degree of content correspondence between local school or training program curricula, and the test of interest. This posited relationship between test-curriculum correspondence, or "alignment,"…

  17. Play for Performance: Using Computer Games to Improve Motivation and Test-Taking Performance

    Science.gov (United States)

    Dennis, Alan R.; Bhagwatwar, Akshay; Minas, Randall K.

    2013-01-01

    The importance of testing, especially certification and high-stakes testing, has increased substantially over the past decade. Building on the "serious gaming" literature and the psychology "priming" literature, we developed a computer game designed to improve test-taking performance using psychological priming. The game primed…

  18. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2005-04-27

    The objective of this program is to develop a system to both monitor the vibration of a bottomhole assembly, and to adjust the properties of an active damper in response to these measured vibrations. Phase I of this program, which entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype, was completed on May 31, 2004. The principal objectives of Phase II are: more extensive laboratory testing, including the evaluation of different feedback algorithms for control of the damper; design and manufacture of a field prototype system; and, testing of the field prototype in drilling laboratories and test wells. As a result of the lower than expected performance of the MR damper noted last quarter, several additional tests were conducted. These dealt with possible causes of the lack of dynamic range observed in the testing: additional damping from the oil in the Belleville springs; changes in properties of the MR fluid; and, residual magnetization of the valve components. Of these, only the last was found to be significant. By using a laboratory demagnetization apparatus between runs, a dynamic range of 10:1 was achieved for the damper, more than adequate to produce the needed improvements in drilling. Additional modeling was also performed to identify a method of increasing the magnetic field in the damper. As a result of the above, several changes were made in the design. Additional circuitry was added to demagnetize the valve as the field is lowered. The valve was located to above the Belleville springs to reduce the load placed upon it and offer a greater range of materials for its construction. In addition, to further increase the field strength, the coils were relocated from the mandrel to the outer housing. At the end of the quarter, the redesign was complete and new parts were on order. The project is approximately three months behind schedule at this time.

  19. Influence of music on Wingate Anaerobic Test performance.

    Science.gov (United States)

    Pujol, T J; Langenfeld, M E

    1999-02-01

    While several studies have investigated the effects of music on cardiovascular endurance performance and perceived exertion during exercise of moderate intensity, few studies have investigated such effects on supramaximal exercise bouts. The purpose of the present study was to assess whether music affects performance on the Wingate Anaerobic Test. Each of the 12 men and 3 women were required to report to the laboratory on two occasions, once for tests in the music condition and once for tests in the nonmusic condition. Conditions were randomly ordered. All music selections were set at the same tempo. On each test day subjects performed a series of three Wingate Anaerobic Tests with 30-sec. rests in between. On Test 3 subjects were asked to continue pedaling until fatigued. Mean Power Output, Maximum Power Output, Minimum Power Output, and Fatigue Index were compared between conditions for each test using a repeated-measures analysis of variance. Time to fatigue on Trial 3 compared by analysis of variance gave no significant differences between conditions for any measures.

  20. Vibration Analysis of a Residential Building

    Directory of Open Access Journals (Sweden)

    Sampaio Regina Augusta

    2015-01-01

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

  1. Development and evaluation of a generic active helicopter vibration controller

    Science.gov (United States)

    Davis, M. W.

    1984-01-01

    A computerized generic active controller is developed, which alleviates helicopter vibration by closed-loop implementation of higher harmonic control (HHC). In the system, the higher harmonic blade pitch is input through a standard helicopter swashplate; for a four-blade helicopter rotor the 4/rev vibration in the rotorcraft is minimized by inducing cyclic pitch motions at 3, 4, and 5/rev in the rotating system. The controller employs the deterministic, cautious, and dual control approaches and two linear system models (local and global), as well as several methods of limiting control. Based on model testing, performed at moderate to high values of forward velocity and rotor thrust, reductions in the rotor test apparatus vibration from 75 to 95 percent are predicted, with HHC pitch amplitudes of less than one degree. Good performance is also noted for short-duration maneuvers.

  2. A further test of the inverted-U hypothesis relating achievement anxiety and academic test performance.

    Science.gov (United States)

    Munz, S C; Costello, C T; Korabik, K

    1975-01-01

    The assumption that the inverted-U hypothesis, which shows performance as a function of activation level, mediates the relationship between achievement anxiety and academic test performance was tested by comparing Achievement Anxiety Test scores of 75 male and female college students with a self-report measure of activation taken prior to a classroom examination. Results supported the predicted relationship between achievement anxiety reaction type and academic performance (rho less than .05), but only partially supported the inverted-U hypothesis posited to account for this relationship. Results were further interpreted as suggesting that examinees experience two general types of arousal in the testing situationōne type that enhances performance and one that impedes performance. Further implications of the results were discussed.

  3. The Effect of Content Familiarity and Test Format on Iranian EFL Test Takers’ Performance on Test of Reading Comprehension

    Directory of Open Access Journals (Sweden)

    Omid Rezaei

    2012-09-01

    Full Text Available This study investigated the effect of content familiarity and test format on Iranian English learners. The participants of this were advanced students studying at different language institutes in Isfahan, Iran. To sample the subjects of this study, the latest version of Oxford Placement Test was administered to 428 students studying at advanced level in 6 different language institutes. Based on the results of the OPT test and for the sake of homogeneity 70 students were considered as the target participants of the study. Each participant was given a test of reading comprehension with familiar content and unfamiliar content. Each test contained multiple choice, true/false, and fill in the blanks test items. Factorial design results indicated that test takers had a significantly better performance on content familiar tests and sub tests. It also became clear that their performance on multiple choice section either in content familiar and content unfamiliar test was superior to that of true/false and fill in the blanks. It will be of endless help to test makers and language teachers to be aware of the role test format and content of the test can play on test takers’ performance.

  4. Effects of bogus feedback on intelligence test performance.

    Science.gov (United States)

    Rousseau, F L; McKelvie, S J

    2000-01-01

    French-Canadian high school students (N = 196) completed different forms of the Wonderlic Personnel Test (WPT; E. F. Wonderlic, 1983) on two occasions. Before the second test, they received negative or positive bogus feedback about their initial performance. Most students (n = 158) were informed that the WPT measured intelligence, and the instruction was issued before either the first (n = 42) or the second test (n = 116). In the latter case, WPT validity either was not mentioned (n = 36) or was described as high or low (ns = 39 and 41, respectively). WPT performance improved on the second test, but it was not related to feedback in any of the instruction conditions. Reasons for these results and their practical implications are discussed.

  5. The relation between psychometric test performance and physical performance in older adults.

    Science.gov (United States)

    Binder, E F; Storandt, M; Birge, S J

    1999-08-01

    The relationship between cognitive function and physical disability in nondemented older adults is not well characterized. The purpose of this study was to determine the relationship between performance on psychometric measures and a modified Physical Performance Test (modified PPT) in older men and women. One hundred twenty-five men and women aged 75 years and older, who were enrolled in randomized, controlled trials of exercise or hormone replacement therapy, were recruited from the community-at-large and from congregate living sites. Measures obtained included Trailmaking A and B tests, Cancellation Random Figure tests, Weschler Associate Learning and 20-minute Delayed Recall, Verbal Fluency test, a modified PPT, and self-reports about performance of activities of daily living, medication use, and hospitalization in the previous year. Simple regression analysis demonstrated that speed of performance on the Trailmaking B and Cancellation Random Figure tests was significantly associated with total modified PPT score (r = .29, p test battery demonstrated that two factors, a cognitive speed factor and a memory factor, accounted for 55% of the variance in cognitive test performance. Hierarchical multiple regression analyses demonstrated that age, number of medications, and the cognitive speed factor were independent predictors of total modified PPT score. Cognitive processing speed is a significant component of physical frailty in this population, although it accounts for a small percentage of variance on a standardized physical performance test.

  6. Cleft Palate Children: Performance In Auditory Processing Tests

    OpenAIRE

    Boscariol M.; Andre K.D.; Feniman M.R.

    2009-01-01

    Many children with auditory processing disorders have a high prevalence of otitis media, a middle ear alterations greatly prevalent in children with palatine and lip clefts. Aim: to check the performance of children with palate cleft alone (PC) in auditory processing tests. Prospective study. Materials and Methods: twenty children (7 to 11 years) with CP were submitted to sound location tests (SL), memory for verbal sounds (MSSV) and non verbal sounds in sequence (MSSNV), Revised auditory fus...

  7. Relationships Between Anaerobic Performance, Field Tests and Game Performance of Sitting Volleyball Players

    Directory of Open Access Journals (Sweden)

    Marszalek Jolanta

    2015-12-01

    Full Text Available The aim of this study was to evaluate relationships between anaerobic performance, field tests, game performance and anthropometric variables of sitting volleyball players. Twenty elite Polish sitting volleyball players were tested using the 30 s Wingate Anaerobic Test for arm crank ergometer and participated in six physical field tests. Heights in position to block and to spike, as well as arm reach were measured. Players were observed during the game on the court in terms of effectiveness of the serve, block, attack, receive and defense. Pearson analysis and the Spearman's rank correlation coefficient were used. The strongest correlations were found between the chest pass test and mean power and peak power (r=.846; p=.001 and r=.708; p=.0005, respectively, and also between the T-test and peak power (r= −.718; p=.001. Mean power correlated with the 3 m test (r= −.540; p=.014, the 5 m test (r= −.592; p=.006, and the T-test (r= −.582; p=.007. Peak power correlated with the 3 m test (r= −.632; p=.003, the 5 m test (r= −.613; p=.004, speed & agility (r= −.552; p=.012 and speed & endurance (r=−.546; p=.013. Significant correlations were observed between anthropometric parameters and anaerobic performance variables (p≤.001, and also between anthropometric parameters and field tests (p≤.05. Game performance and physical fitness of sitting volleyball players depended on their anthropometric variables: reach of arms, the position to block and to spike. The chest pass test could be used as a non-laboratory field test of anaerobic performance of sitting volleyball players.

  8. Relationships Between Anaerobic Performance, Field Tests and Game Performance of Sitting Volleyball Players.

    Science.gov (United States)

    Marszalek, Jolanta; Molik, Bartosz; Gomez, Miguel Angel; Skučas, Kęstutis; Lencse-Mucha, Judit; Rekowski, Witold; Pokvytyte, Vaida; Rutkowska, Izabela; Kaźmierska-Kowalewska, Kalina

    2015-11-22

    The aim of this study was to evaluate relationships between anaerobic performance, field tests, game performance and anthropometric variables of sitting volleyball players. Twenty elite Polish sitting volleyball players were tested using the 30 s Wingate Anaerobic Test for arm crank ergometer and participated in six physical field tests. Heights in position to block and to spike, as well as arm reach were measured. Players were observed during the game on the court in terms of effectiveness of the serve, block, attack, receive and defense. Pearson analysis and the Spearman's rank correlation coefficient were used. The strongest correlations were found between the chest pass test and mean power and peak power (r=.846; p=.001 and r=.708; p=.0005, respectively), and also between the T-test and peak power (r= -.718; p=.001). Mean power correlated with the 3 m test (r= -.540; p=.014), the 5 m test (r= -.592; p=.006), and the T-test (r= -.582; p=.007). Peak power correlated with the 3 m test (r= -.632; p=.003), the 5 m test (r= -.613; p=.004), speed & agility (r= -.552; p=.012) and speed & endurance (r=-.546; p=.013). Significant correlations were observed between anthropometric parameters and anaerobic performance variables (p≤.001), and also between anthropometric parameters and field tests (p≤.05). Game performance and physical fitness of sitting volleyball players depended on their anthropometric variables: reach of arms, the position to block and to spike. The chest pass test could be used as a non-laboratory field test of anaerobic performance of sitting volleyball players.

  9. Test anxiety and academic performance in chiropractic students*

    Science.gov (United States)

    Zhang, Niu; Henderson, Charles N. R.

    2014-01-01

    Objective We assessed the level of students' test anxiety, and the relationship between test anxiety and academic performance. Methods We recruited 166 third-quarter students. The Test Anxiety Inventory (TAI) was administered to all participants. Total scores from written examinations and objective structured clinical examinations (OSCEs) were used as response variables. Results Multiple regression analysis shows that there was a modest, but statistically significant negative correlation between TAI scores and written exam scores, but not OSCE scores. Worry and emotionality were the best predictive models for written exam scores. Mean total anxiety and emotionality scores for females were significantly higher than those for males, but not worry scores. Conclusion Moderate-to-high test anxiety was observed in 85% of the chiropractic students examined. However, total test anxiety, as measured by the TAI score, was a very weak predictive model for written exam performance. Multiple regression analysis demonstrated that replacing total anxiety (TAI) with worry and emotionality (TAI subscales) produces a much more effective predictive model of written exam performance. Sex, age, highest current academic degree, and ethnicity contributed little additional predictive power in either regression model. Moreover, TAI scores were not found to be statistically significant predictors of physical exam skill performance, as measured by OSCEs. PMID:24350946

  10. Test anxiety and academic performance in chiropractic students.

    Science.gov (United States)

    Zhang, Niu; Henderson, Charles N R

    2014-01-01

    Objective : We assessed the level of students' test anxiety, and the relationship between test anxiety and academic performance. Methods : We recruited 166 third-quarter students. The Test Anxiety Inventory (TAI) was administered to all participants. Total scores from written examinations and objective structured clinical examinations (OSCEs) were used as response variables. Results : Multiple regression analysis shows that there was a modest, but statistically significant negative correlation between TAI scores and written exam scores, but not OSCE scores. Worry and emotionality were the best predictive models for written exam scores. Mean total anxiety and emotionality scores for females were significantly higher than those for males, but not worry scores. Conclusion : Moderate-to-high test anxiety was observed in 85% of the chiropractic students examined. However, total test anxiety, as measured by the TAI score, was a very weak predictive model for written exam performance. Multiple regression analysis demonstrated that replacing total anxiety (TAI) with worry and emotionality (TAI subscales) produces a much more effective predictive model of written exam performance. Sex, age, highest current academic degree, and ethnicity contributed little additional predictive power in either regression model. Moreover, TAI scores were not found to be statistically significant predictors of physical exam skill performance, as measured by OSCEs.

  11. Performance testing of a two-phase interface heat exchanger

    Science.gov (United States)

    Mccabe, M. E., Jr.; Swanson, T. D.

    1989-01-01

    This paper describes the design and performance testing of a heat exchanger which interfaces separate two-phase ammonia thermal loops. The basic design involves a tube-in-tube concept, with boiling occurring in the inner tube and condensation in the outer tube. Eight such tubes are arranged in parallel. Testing has demonstrated that up to 8.2 kW of heat may be transferred across the heat exchanger when the saturation temperature difference between the systems is 5 C. Performance of the heat exchanger is affected primarily by the mass flow rate of ammonia in the liquid supply loop.

  12. Power Performance Test Report for the SWIFT Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, I.; Hur, J.

    2012-12-01

    This report summarizes the results of a power performance test that NREL conducted on the SWIFT wind turbine. This test was conducted in accordance with the International Electrotechnical Commission's (IEC) standard, Wind Turbine Generator Systems Part 12: Power Performance Measurements of Electricity Producing Wind Turbines, IEC 61400-12-1 Ed.1.0, 2005-12. However, because the SWIFT is a small turbine as defined by IEC, NREL also followed Annex H that applies to small wind turbines. In these summary results, wind speed is normalized to sea-level air density.

  13. Enhancement on Wingate Anaerobic Test Performance With Hyperventilation.

    Science.gov (United States)

    Leithäuser, Renate M; Böning, Dieter; Hütler, Matthias; Beneke, Ralph

    2016-07-01

    Relatively long-lasting metabolic alkalizing procedures such as bicarbonate ingestion have potential for improving performance in long-sprint to middle-distance events. Within a few minutes, hyperventilation can induce respiratory alkalosis. However, corresponding performance effects are missing or equivocal at best. To test a potential performance-enhancing effect of respiratory alkalosis in a 30-s Wingate Anaerobic Test (WAnT). 10 men (mean ± SD age 26.6 ± 4.9 y, height 184.4 ± 6.1 cm, body-mass test 1 80.7 ± 7.7 kg, body-mass test 2 80.4 ± 7.2 kg, peak oxygen uptake 3.95 ± 0.43 L/min) performed 2 WAnTs, 1 with and 1 without a standardized 15-min hyperventilation program pre-WAnT in randomized order separated by 1 wk. Compared with the control condition, hyperventilation reduced (all P Hyperventilation-induced respiratory alkalosis can enhance WAnT cycling sprint performance well in the magnitude of what is seen after successful bicarbonate ingestion.

  14. Fertilization test performance using Arbacia punctulata maintained in static culture

    Energy Technology Data Exchange (ETDEWEB)

    Serbst, J.R. [Environmental Protection Agency, Narragansett, RI (United States). Environmental Research Lab.; Wright, L.; Sheehan, C.V.; Fitzpatrick, K. [Science Applications International Corp., Narragansett, RI (United States)

    1995-12-31

    The sea urchin fertilization test using the Atlantic urchin, Arbacia punctulata, is widely utilized in evaluating toxicity of receiving waters and effluents as part of the NPDES program. While this species is easily maintained in uncontaminated, flow-through seawater systems, laboratories without access to flowing seawater either obtain new urchins for each test or maintain populations in static cultures. This study was conducted to assess test success and reproducibility of fertilization tests conducted using urchins maintained in separate-sex, static, temperature-controlled aquaria containing filtered natural seawater. Test performance was evaluated by periodically conducting the standard sea urchin fertilization test (EPA 600/4-87-028) using a common reference toxicant, sodium dodecyl sulfate (SDS) Thirteen tests were conducted between September 1993 and May 1994 using one population of urchins, and five tests were conducted between June and December 1994 with a second population of urchins. Test success was 100% (control fertilization > 50%) with a control fertilization mean of 96.4% (S.D. = 3.3). There were no differences between mean EC{sub 50} values calculated for each set of tests (p < 0.05). The running mean value for toxicity was 7.1 mg/L (S.D. = 1.26) for 18 tests, with a CV of 17.7%, comparing favorably with values generated using urchins maintained in flowing seawater. The running mean value for toxicity in these tests was 2.4 mg/L (S.D. = 0.9) for 18 tests conducted between November 1987 and July 1989 (ASTM STP 1124). Data from all urchin tests were used to construct a control chart defining normal ranges for SDS toxicity. This study demonstrated that fertile, adult sea urchins can produce consistent toxicity responses with low variability while being maintained in static, temperature regulated culture facilities.

  15. Testing a Model of Work Performance in an Academic Environment

    OpenAIRE

    B. Charles Tatum

    2012-01-01

    In modern society, people both work and study. The intersection between organizational and educational research suggests that a common model should apply to both academic and job performance. The purpose of this study was to apply a model of work and job performance (based on general expectancy theory) to a classroom setting, and test the predicted relationships using a causal/path model methodology. The findings revea...

  16. Wisconsin Card Sorting Test Performance after Putaminal Hemorrhagic Stroke

    OpenAIRE

    Su, Chwen-Yng; Wuang, Yee-Pay; Chang, Jui-Kun; Guo, Nai-Wen; Kwan, Aij-Lie

    2006-01-01

    The purpose of this study was to compare the performance differences in the Wisconsin Card Sorting Test (WCST) between 55 patients with putaminal hemorrhage (PH) 3 months after stroke and 69 age-matched normal controls. Impairment on WCST was defined as performance greater than 1.64 standard deviation below the control mean. A multivariate analysis of covariance (MANCOVA) controlling for education yielded a significant main effect for group but not for education and interaction of group × edu...

  17. Experimental Study on Interfacial Area Transport of Two-Phase Flow under Vibration Conditions

    Directory of Open Access Journals (Sweden)

    Xiu Xiao

    2017-01-01

    Full Text Available An experimental study on air-water two-phase flow under vibration condition has been conducted using double-sensor conductivity probe. The test section is an annular geometry with hydraulic diameter of 19.1 mm. The vibration frequency ranges from 0.47 Hz to 2.47 Hz. Local measurements of void fraction, interfacial area concentration (IAC, and Sauter mean diameter have been performed along one radius in the vibration direction. The result shows that local parameters fluctuate continuously around the base values in the vibration cycle. Additional bubble force due to inertia is used to explain lateral bubble motions. The fluctuation amplitudes of local void fraction and IAC increase significantly with vibration frequency. The radial distribution of local parameters at the maximum vibration displacement is specifically analyzed. In the void fraction and IAC profiles, the peak near the inner wall is weakened or even disappearing and a strong peak skewed to outer wall is gradually observed with the increase of vibration frequency. The nondimensional peak void fraction can reach a maximum of 49% and the mean relative variation of local void fraction can increase to more than 29% as the vibration frequency increases to 2.47 Hz. But the increase of vibration frequency does not bring significant change to bubble diameter.

  18. Effect of Bio Ethanol and Diesel Blend on Small Diesel Engine Vibration

    Directory of Open Access Journals (Sweden)

    S.H Hashemi Fard

    2014-09-01

    Full Text Available The use of Bio-ethanol as an alternative diesel engine fuel is rapidly increasing. Bio-ethanol is mixed with diesel fuel at different ratios and used in CI and SI engines. Since vibrations have direct effects on users and engine components, for this reason analysis of vibration resulting from combustion in CI engines is very important. In this study, evaluation of vibration was performed for both diesel and ethanol blends. Commercial diesel fuel (D100, E2 (2% ethanol and 98% diesel fuel, E5, E10, E15 and E20 were used in a two-wheel MITSUBISHI tractor. The engine was tested in 1200, 1600, 2000 and 2400 rpm for all fuel blends, and also the effect of load was investigated for D100 and E10. Results showed that vibration is significantly affected by fuel blend. It was observed that E10 had the lowest vibration while E20 had the highest value. It was also observed that vibration increased as engine speed increased for all fuel blends. It was found that both axial and lateral vibrations affected significantly by load. The lateral vibrations decreased continuously with load rise , but the axial vibrations increased initially but started to follow a reverse trend.

  19. Stereotype threat? Effects of inquiring about test takers' gender on conceptual test performance in physics

    Science.gov (United States)

    Maries, Alexandru; Singh, Chandralekha

    2015-12-01

    It has been found that activation of a stereotype, for example by indicating one's gender before a test, typically alters performance in a way consistent with the stereotype, an effect called "stereotype threat." On a standardized conceptual physics assessment, we found that asking test takers to indicate their gender right before taking the test did not deteriorate performance compared to an equivalent group who did not provide gender information. Although a statistically significant gender gap was present on the standardized test whether or not students indicated their gender, no gender gap was observed on the multiple-choice final exam students took, which included both quantitative and conceptual questions on similar topics.

  20. Stereotype threat? Effects of inquiring about test takers' gender on conceptual test performance in physics

    CERN Document Server

    Maries, Alexandru

    2016-01-01

    It has been found that activation of a stereotype, for example by indicating one's gender before a test, typically alters performance in a way consistent with the stereotype, an effect called "stereotype threat". On a standardized conceptual physics assessment, we found that asking test takers to indicate their gender right before taking the test did not deteriorate performance compared to an equivalent group who did not provide gender information. Although a statistically significant gender gap was present on the standardized test whether or not students indicated their gender, no gender gap was observed on the multiple-choice final exam students took, which included both quantitative and conceptual questions on similar topics.

  1. Spherical tuned liquid damper for vibration control in wind turbines

    DEFF Research Database (Denmark)

    Chen, Jun-Ling; Georgakis, Christos T.

    2015-01-01

    A tuned liquid damper (TLD), which consisted of two-layer hemispherical containers, partially filled with water, was investigated as a cost-effective method to reduce the wind-induced vibration of wind turbines. A 1/20 scaled test model was designed to investigate its performance on the shaking...... table. Three groups of equivalent ground accelerations were inputted to simulate the wind-induced dynamic response under different load cases. The influence of rotors and nacelle was assumed to be a concentrated tip mass. A series of free and forced vibration experiments were performed on the shaking...

  2. Performance test of solar-assisted ejector cooling system

    KAUST Repository

    Huang, Bin-Juine

    2014-03-01

    A solar-assisted ejector cooling/heating system (SACH-2k) is built and test result is reported. The solar-driven ejector cooling system (ECS) is connected in series with an inverter-type air conditioner (IAC). Several advanced technologies are developed in SACH-k2, including generator liquid level control in ECS, the ECS evaporator temperature control, and optimal control of fan power in cooling tower of ECS. From the field test results, the generator liquid level control performs quite well and keeps stable performance of ejector. The ECS evaporator temperature control also performs satisfactorily to keep ejector performance normally under low or fluctuating solar radiation. The fan power control system cooling tower performs stably and reduces the power consumption dramatically without affecting the ECS performance. The test results show that the overall system COPo including power consumptions of peripheral increases from 2.94-3.3 (IAC alone) to 4.06-4.5 (SACH-k2), about 33-43%. The highest COPo is 4.5. © 2013 Elsevier Ltd and IIR. All rights reserved.

  3. Effort, symptom validity testing, performance validity testing and traumatic brain injury

    Science.gov (United States)

    Bigler, Erin D.

    2014-01-01

    Abstract Background: To understand the neurocognitive effects of brain injury, valid neuropsychological test findings are paramount. Review: This review examines the research on what has been referred to a symptom validity testing (SVT). Above a designated cut-score signifies a ‘passing’ SVT performance which is likely the best indicator of valid neuropsychological test findings. Likewise, substantially below cut-point performance that nears chance or is at chance signifies invalid test performance. Significantly below chance is the sine qua non neuropsychological indicator for malingering. However, the interpretative problems with SVT performance below the cut-point yet far above chance are substantial, as pointed out in this review. This intermediate, border-zone performance on SVT measures is where substantial interpretative challenges exist. Case studies are used to highlight the many areas where additional research is needed. Historical perspectives are reviewed along with the neurobiology of effort. Reasons why performance validity testing (PVT) may be better than the SVT term are reviewed. Conclusions: Advances in neuroimaging techniques may be key in better understanding the meaning of border zone SVT failure. The review demonstrates the problems with rigidity in interpretation with established cut-scores. A better understanding of how certain types of neurological, neuropsychiatric and/or even test conditions may affect SVT performance is needed. PMID:25215453

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  5. Tndon vibration does not alter recovery time following fatigue.

    Science.gov (United States)

    Christie, Anita D; Miller, Nick R

    2015-05-01

    Tendon vibration has been shown to enhance muscle activity and to increase muscular endurance times. The impact of vibration on recovery from fatigue, however, is not known. This study aims to determine whether tendon vibration reduces recovery time following fatiguing contractions. Eight sedentary males (22 ± 2.8 yr) performed a fatiguing protocol of ankle dorsiflexor muscles on two separate days, with a minimum of 48 h between visits. Surface EMG was recorded from the tibialis anterior muscle while participants were performing 25 maximal voluntary contractions (MVCs), each lasting 5 s and separated by 2 s. Following the fatiguing protocol, recovery was assessed with 3-s MVC each minute over a 10-min period. Recovery time was defined as the time at which force had returned to 90% of baseline values. At one visit, vibration was applied to the distal tendon of the tibialis anterior muscle between MVCs (throughout recovery). The alternate visit involved a sham condition in which no vibration was applied. MVC force (P = 0.48) and EMG amplitude (P = 0.26) were not significantly different across testing days. Both MVC force (P fatigue protocol. However, there were no significant interaction effects for MVC force (P = 0.82) or EMG amplitude (P = 0.09), indicating similar levels of fatigue across days. With tendon vibration, MVC force recovered within 4.0 ± 2.5 min, which was not different from the sham condition (5.3 ± 1.8 min; P = 0.42). Similarly, EMG recovery time was not different between vibration condition (3.9 ± 3.8 min) and sham condition (4.9 ± 2.5 min) (P = 0.41). These results suggest that activation of excitatory group Ia afferents through tendon vibration does not substantially alter recovery time following fatigue.

  6. The testing effect in general chemistry: Effects of repeated testing on student performance across different test modes

    Science.gov (United States)

    Prisacari, Anna Agripina

    Research on the testing effect shows that practice tests are more effective than additional studying for enhancing learning. However, there has been little research directly addressing the role of additional testing when students take paper-based or computer-based tests in college courses. Accordingly, the purpose of this study was to investigate the role of the testing effect and test mode on student performance. The participants were 664 general chemistry students from two large universities in the Midwest and the Pacific Northwest. After covering the test material in their course, students completed two proctored practice tests that included 17 algorithmic question pairs, 5 conceptual pairs, and 2 definition pairs. Each practice test was delivered on computer or paper according to one of four conditions that were defined by the mode of the initial test and the mode of the final test. These conditions were: Computer-Computer, Computer-Paper, Paper-Computer, and Paper-Paper. After completing the initial practice test, students repeated half of the items. Feedback was provided after each test and performance was measured with normalized gains. After completing all of the tests, students were asked to indicate and explain their test mode preferences for general chemistry tests. Four major conclusions resulted from the study. First, the testing effect was found in all conditions, but varied in terms of the test mode. Paper-Computer showed the lowest gains and these gains were significantly lower than those for Paper-Paper. Gains from Computer-Paper and Paper-Paper were not significantly different from each other. Second, the test mode did not affect the students' performance on algorithmic questions, but affected their performance on conceptual and definition questions. Third, the gains from repeated items were significantly higher than the gains from non-repeated items. However, this testing effect was not consistent across all areas of chemistry content. Fourth, a

  7. Radiometric instrumentation and measurements guide for photovoltaic performance testing

    Energy Technology Data Exchange (ETDEWEB)

    Myers, D.

    1997-04-01

    The Photovoltaic Module and Systems Performance and Engineering Project at the National Renewable Energy Laboratory performs indoor and outdoor standardization, testing, and monitoring of the performance of a wide range of photovoltaic (PV) energy conversion devices and systems. The PV Radiometric Measurements and Evaluation Team (PVSRME) within that project is responsible for measurement and characterization of natural and artificial optical radiation which stimulates the PV effect. The PV manufacturing and research and development community often approaches project members for technical information and guidance. A great area of interest is radiometric instrumentation, measurement techniques, and data analysis applied to understanding and improving PV cell, module, and system performance. At the Photovoltaic Radiometric Measurements Workshop conducted by the PVSRME team in July 1995, the need to communicate knowledge of solar and optical radiometric measurements and instrumentation, gained as a result of NREL`s long-term experiences, was identified as an activity that would promote improved measurement processes and measurement quality in the PV research and manufacturing community. The purpose of this document is to address the practical and engineering need to understand optical and solar radiometric instrument performance, selection, calibration, installation, and maintenance applicable to indoor and outdoor radiometric measurements for PV calibration, performance, and testing applications. An introductory section addresses radiometric concepts and definitions. Next, concepts essential to spectral radiometric measurements are discussed. Broadband radiometric instrumentation and measurement concepts are then discussed. Each type of measurement serves as an important component of the PV cell, module, and system performance measurement and characterization process.

  8. GPM Avionics Module Heat Pipes Design and Performance Test Results

    Science.gov (United States)

    Ottenstein, Laura; DeChristopher, Mike

    2011-01-01

    The Global Precipitation Measurement (GPM) mission is an international network of satellites that provide the next-generation global observations of rain and snow. The GPM core satellite carries an advanced radar / radiometer system to measure precipitation from space and serve as a reference standard to unify precipitation measurements from a constellation of research and operational satellites. Through improved measurements of precipitation globally, the GPM mission will help to advance our understanding of Earth's water and energy cycle, improve forecasting of extreme events that cause natural hazards and disasters, and extend current capabilities in using accurate and timely information of precipitation to directly benefit society. The avionics module on the core satellite contains a number of electronics boxes which are cooled by a network of aluminum/ammonia heat pipes and a honeycomb radiator which contains thirteen embedded aluminum/ammonia heat pipes. All heat pipes were individually tested by the vendor (Advanced Cooling Technologies, Inc.) prior to delivery. Following delivery to NASA, the flight avionics radiator and the flight spare transport heat pipes were mounted to flight-like test structure and a system level thermal vacuum test was performed. This test, which used simulators in place of all electronics boxes, was done to verify the operation of the thermal control system as a whole. This presentation will discuss the design of the avionics module heat pipes, and then discuss performance tests results for the individual heat pipes prior to delivery and for the system level thermal vacuum test. All heat pipes met their performance requirements. However, it was found that the power was too low in some instances to start all of the smaller radiator spreader heat pipes when they were tested in a reflux configuration (which is the nominal test configuration). Although this lowered the efficiency of the radiator somewhat, it did not impact the operating

  9. Effective Rating Scale Development for Speaking Tests: Performance Decision Trees

    Science.gov (United States)

    Fulcher, Glenn; Davidson, Fred; Kemp, Jenny

    2011-01-01

    Rating scale design and development for testing speaking is generally conducted using one of two approaches: the measurement-driven approach or the performance data-driven approach. The measurement-driven approach prioritizes the ordering of descriptors onto a single scale. Meaning is derived from the scaling methodology and the agreement of…

  10. Thermal Performance Testing of Order Dependancy of Aerogels Multilayered Insulation

    Science.gov (United States)

    Johnson, Wesley L.; Fesmire, James E.; Demko, J. A.

    2009-01-01

    Robust multilayer insulation systems have long been a goal of many research projects. Such insulation systems must provide some degree of structural support and also mechanical integrity during loss of vacuum scenarios while continuing to provide insulative value to the vessel. Aerogel composite blankets can be the best insulation materials in ambient pressure environments; in high vacuum, the thermal performance of aerogel improves by about one order of magnitude. Standard multilayer insulation (MU) is typically 50% worse at ambient pressure and at soft vacuum, but as much as two or three orders of magnitude better at high vacuum. Different combinations of aerogel and multilayer insulation systems have been tested at Cryogenics Test Laboratory of NASA Kennedy Space Center. Analysis performed at Oak Ridge National Laboratory showed an importance to the relative location of the MU and aerogel blankets. Apparent thermal conductivity testing under cryogenic-vacuum conditions was performed to verify the analytical conclusion. Tests results are shown to be in agreement with the analysis which indicated that the best performance is obtained with aerogel layers located in the middle of the blanket insulation system.

  11. 40 CFR 63.309 - Performance tests and procedures.

    Science.gov (United States)

    2010-07-01

    ... alternative standards for coke oven doors under § 63.305; work practice emission control plan requirements in... Standards for Coke Oven Batteries § 63.309 Performance tests and procedures. (a) Except as otherwise... coke oven battery, the results of which shall be used in accordance with procedures specified in this...

  12. Performance testing and certification of small solar heating systems

    NARCIS (Netherlands)

    Pauschinger, Th.

    1996-01-01

    Performance testing and certification of solar heating systems are taking the step from research to practical use. This is shown by the increasing activities on this field on several European markets and, even more clearly, by the Draft European Standards (prEN) for solar heating systems, which will

  13. Performance on Multiple-Choice Tests and Penalty for Guessing

    Science.gov (United States)

    Quereshi, M. Y.

    1974-01-01

    The purpose of the present study was to investigate the effects on various aspects of test performance of the information about the relative merits of guessing in relation to such characteristics as sex and intellectual or achievement level of the individual. (Author)

  14. Power performance under constant speed test with palm oil ...

    African Journals Online (AJOL)

    The torque and power. performance tests were carried out with a single cylinder techno four-stroke diesel engine under constant speeds of 2000, 1500 and 1100rpm. Five fuels, the Dura Palm Oil biodiesel, 81100; Tenera Palm oil biodiesel, B2100; Dura Palm Oil biodiesel/diesel blend at 10/90 vol/vol, B110; Tenera Palm oil ...

  15. Social housing improves dairy calves' performance in two cognitive tests.

    Directory of Open Access Journals (Sweden)

    Charlotte Gaillard

    Full Text Available Early social housing is known to benefit cognitive development in laboratory animals. Pre-weaned dairy calves are typically separated from their dam immediately after birth and housed alone, but no work to date has addressed the effect of individual housing on cognitive performance of these animals. The aim of this study was to determine the effects of individual versus social housing on two measures of cognitive performance: reversal learning and novel object recognition. Holstein calves were either housed individually in a standard calf pen (n = 8 or kept in pairs using a double pen (n = 10. Calves were tested twice daily in a Y-maze starting at 3 weeks of age. Calves were initially trained to discriminate two colours (black and white until they reached a learning criterion of 80% correct over three consecutive sessions. Training stimuli were then reversed (i.e. the previously rewarded colour was now unrewarded, and vice-versa. Calves from the two treatments showed similar rates of learning in the initial discrimination task, but the individually housed calves showed poorer performance in the reversal task. At 7 weeks of age, calves were tested for their response to a novel object in eight tests over a two-day period. Pair-housed calves showed declining exploration with repeated testing but individually reared calves did not. The results of these experiments provide the first direct evidence that individual housing impairs cognitive performance in dairy calves.

  16. Social housing improves dairy calves' performance in two cognitive tests.

    Science.gov (United States)

    Gaillard, Charlotte; Meagher, Rebecca K; von Keyserlingk, Marina A G; Weary, Daniel M

    2014-01-01

    Early social housing is known to benefit cognitive development in laboratory animals. Pre-weaned dairy calves are typically separated from their dam immediately after birth and housed alone, but no work to date has addressed the effect of individual housing on cognitive performance of these animals. The aim of this study was to determine the effects of individual versus social housing on two measures of cognitive performance: reversal learning and novel object recognition. Holstein calves were either housed individually in a standard calf pen (n = 8) or kept in pairs using a double pen (n = 10). Calves were tested twice daily in a Y-maze starting at 3 weeks of age. Calves were initially trained to discriminate two colours (black and white) until they reached a learning criterion of 80% correct over three consecutive sessions. Training stimuli were then reversed (i.e. the previously rewarded colour was now unrewarded, and vice-versa). Calves from the two treatments showed similar rates of learning in the initial discrimination task, but the individually housed calves showed poorer performance in the reversal task. At 7 weeks of age, calves were tested for their response to a novel object in eight tests over a two-day period. Pair-housed calves showed declining exploration with repeated testing but individually reared calves did not. The results of these experiments provide the first direct evidence that individual housing impairs cognitive performance in dairy calves.

  17. Predicting Performance on a Firefighter's Ability Test from Fitness Parameters

    Science.gov (United States)

    Michaelides, Marcos A.; Parpa, Koulla M.; Thompson, Jerald; Brown, Barry

    2008-01-01

    The purpose of this project was to identify the relationships between various fitness parameters such as upper body muscular endurance, upper and lower body strength, flexibility, body composition and performance on an ability test (AT) that included simulated firefighting tasks. A second intent was to create a regression model that would predict…

  18. WhalePower tubercle blade power performance test report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-15

    Toronto-based WhalePower Corporation has developed turbine blades that are modeled after humpback whale flippers. The blades, which incorporate tubercles along the leading edge of the blade, have been fitted to a Wenvor 25 kW turbine installed in North Cape, Prince Edward Island at a test site for the Wind Energy Institute of Canada (WEICan). A test was conducted to characterize the power performance of the prototype wind turbine. This report described the wind turbine configuration with particular reference to turbine information, power rating, blade information, tower information, control systems and grid connections. The test site was also described along with test equipment and measurement procedures. Information regarding power output as a function of wind speed was included along with power curves, power coefficient and annual energy production. The results for the power curve and annual energy production contain a level of uncertainty. While measurements for this test were collected and analyzed in accordance with International Electrotechnical Commission (IEC) standards for performance measurements of electricity producing wind turbines (IEC 61400-12-1), the comparative performance data between the prototype WhalePower wind turbine blade and the Wenvor standard blade was not gathered to IEC data standards. Deviations from IEC-61400-12-1 procedures were listed. 6 tabs., 16 figs., 3 appendices.

  19. Modelling of LOCA Tests with the BISON Fuel Performance Code

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, Richard L [Idaho National Laboratory; Pastore, Giovanni [Idaho National Laboratory; Novascone, Stephen Rhead [Idaho National Laboratory; Spencer, Benjamin Whiting [Idaho National Laboratory; Hales, Jason Dean [Idaho National Laboratory

    2016-05-01

    BISON is a modern finite-element based, multidimensional nuclear fuel performance code that is under development at Idaho National Laboratory (USA). Recent advances of BISON include the extension of the code to the analysis of LWR fuel rod behaviour during loss-of-coolant accidents (LOCAs). In this work, BISON models for the phenomena relevant to LWR cladding behaviour during LOCAs are described, followed by presentation of code results for the simulation of LOCA tests. Analysed experiments include separate effects tests of cladding ballooning and burst, as well as the Halden IFA-650.2 fuel rod test. Two-dimensional modelling of the experiments is performed, and calculations are compared to available experimental data. Comparisons include cladding burst pressure and temperature in separate effects tests, as well as the evolution of fuel rod inner pressure during ballooning and time to cladding burst. Furthermore, BISON three-dimensional simulations of separate effects tests are performed, which demonstrate the capability to reproduce the effect of azimuthal temperature variations in the cladding. The work has been carried out in the frame of the collaboration between Idaho National Laboratory and Halden Reactor Project, and the IAEA Coordinated Research Project FUMAC.

  20. The evolution and impact of testing baghouse filter performance.

    Science.gov (United States)

    Pham, Minh; Clark, Christina; Mckenna, John

    2012-08-01

    In 1995, the US. Environmental Protection Agency (EPA) initiated the Environmental Technology Verification (ETV) program for the purpose of generating both independent and credible performance verification of innovative technologies and helping to accelerate acceptance of these products into the marketplace to further benefit the environment and protect public health. The EPA has approved a testing protocol under this program to verify the performance of commercially available filtration products for pulse-jet baghouses in removingfine particulate matter (aerodynamic diameter<2.5 microm; PM2.5). This verification testing protocol was later used as a basis for the development of the American Society for Testing and Materials (ASTM) Method D6830-02 and the International Organization for Standardization (ISO) Method 11057. The South Coast Air Quality Management District (SCAQMD) in California and the EPA s Office of Air Quality Planning and Standards (OAQPS) highly encourage the use of ETV/ASTM-verified filtration media. This paper highlights the evolution of the standard test methods, the EPA's and SCAQMD's regulatory activities, the benefits of using verified filtration media, and the importance of including the filter performance testing in future consideration of baghouse permitting, baghouse operation and maintenance (O&M) plans, quality assurance/quality control (QA/QC), and bag monitoring plans.

  1. Investigation of the existence of self compacting properties in high performance concrete through experimental tests

    Directory of Open Access Journals (Sweden)

    Heitor H. Yoshida

    2007-03-01

    Full Text Available The self compacting concrete is characterized by its capacity to flow inside the formwork filling it exclusively by the force of the gravity with adequate cohesion and viscosity in such a way that segregation does not occur. One of its characteristic is the presence of fines which provide the necessary cohesion,and grains with maximum diameter of 20 mm. This work presents some procedures and experimental methods that make it possible to evaluate self compacting properties of high performance concrete. First, a bibliographical review on the subject was carried out, and later, the equipment used for the accomplishment of the assays were manufactured, in order to verify the properties related to the self compacting concrete: cohesion, viscosity and segregation. As for the work, two concretes were produced with Portland ARI Cement, thick sand, stone powder, sand 0, superplasticizer made of ether-carboxilate chains that differentiate from each other for the presence of active silica in one of them and fly ash in the other. Based on the results, it was verified whether the high performance concrete had self compacting characteristics. In this case, both were considered positive. It was also analyzed the behavior of these concretes in their hardened state by means of the compressive strength test. The Self Compacting Concrete has many advantages such as: reduction in the number of employees, shorter construction period, the non-use of the vibrator and the filling of formworks with high density of… or of complex geometry.

  2. Clock face drawing test performance in children with ADHD.

    Science.gov (United States)

    Ghanizadeh, Ahmad; Safavi, Salar; Berk, Michael

    2013-01-01

    The utility and discriminatory pattern of the clock face drawing test in ADHD is unclear. This study therefore compared Clock Face Drawing test performance in children with ADHD and controls. 95 school children with ADHD and 191 other children were matched for gender ratio and age. ADHD symptoms severities were assessed using DSM-IV ADHD checklist and their intellectual functioning was assessed. The participants completed three clock-drawing tasks, and the following four functions were assessed: Contour score, Numbers score, Hands setting score, and Center score. All the subscales scores of the three clock drawing tests of the ADHD group were lower than that of the control group. In ADHD children, inattention and hyperactivity/ impulsivity scores were not related to free drawn clock test scores. When pre-drawn contour test was performed, inattentiveness score was statistically associated with Number score while none of the other variables of age, gender, intellectual functioning, and hand use preference were associated with that kind of score. In pre-drawn clock, no association of ADHD symptoms with any CDT subscales found significant. In addition, more errors are observed with free drawn clock and Pre-drawn contour than pre-drawn clock. Putting Numbers and Hands setting are more sensitive measures to screen ADHD than Contour and Center drawing. Test performance, except Hands setting, may have already reached a developmental plateau. It is probable that Hand setting deficit in children with ADHD may not decrease from age 8 to 14 years. Performance of children with ADHD is associated with complexity of CDT.

  3. Blade Vibration Measurement System

    Science.gov (United States)

    Platt, Michael J.

    2014-01-01

    The Phase I project successfully demonstrated that an advanced noncontacting stress measurement system (NSMS) could improve classification of blade vibration response in terms of mistuning and closely spaced modes. The Phase II work confirmed the microwave sensor design process, modified the sensor so it is compatible as an upgrade to existing NSMS, and improved and finalized the NSMS software. The result will be stand-alone radar/tip timing radar signal conditioning for current conventional NSMS users (as an upgrade) and new users. The hybrid system will use frequency data and relative mode vibration levels from the radar sensor to provide substantially superior capabilities over current blade-vibration measurement technology. This frequency data, coupled with a reduced number of tip timing probes, will result in a system capable of detecting complex blade vibrations that would confound traditional NSMS systems. The hardware and software package was validated on a compressor rig at Mechanical Solutions, Inc. (MSI). Finally, the hybrid radar/tip timing NSMS software package and associated sensor hardware will be installed for use in the NASA Glenn spin pit test facility.

  4. DOE ETV-1 electric test vehicle. Phase III: performance testing and system evaluation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, D. W.

    1981-12-01

    The DOE ETV-1 represents the most advanced electric vehicle in operation today. Engineering tests have been conducted by the Jet Propulsion Laboratory in order to characterize its overall system performance and component efficiencies within the system environment. A dynamometer was used in order to minimize the ambient effects and large uncertainties present in track testing. Extensive test requirements have been defined and procedures were carefully controlled in order to maintain a high degree of credibility. Limited track testing was performed in order to corroborate the dynamometer results. Test results include an energy flow analysis through the major subsystems and incorporate and aerodynamic and rolling losses under cyclic and various steady speed conditions. A complete summary of the major output from all relevant dynamometer and track tests is also included as an appendix.

  5. Evaluation of Emergency-Locator-Transmitter performance in real and simulated crash tests

    Science.gov (United States)

    Carden, H. D.

    1981-01-01

    Emergency locator transmitter (ELT) activation problems were investigated by testing a sampling of ELT units in actual crashes and in a special test apparatus which simulated longitudinal crash pulses with superimposed local structural resonances. The probable causes of excessive false alarms and nonactivation of ELT's during crash situations were determined. Solutions to operational and technical problems were also examined as well as the sensitivity of ELT impact switches to orientation and to local structural vibrations.

  6. Differences in gender performance on competitive physics selection tests

    Directory of Open Access Journals (Sweden)

    Kate Wilson

    2016-08-01

    Full Text Available [This paper is part of the Focused Collection on Gender in Physics.] We have investigated gender differences in performance over the past eight years on the Australian Science Olympiad Exam (ASOE for physics, which is taken by nearly 1000 high school students each year. The ASOE, run by Australian Science Innovations (ASI, is the initial stage of the process of selection of teams to represent Australia at the Asian and International Physics Olympiads. Students taking the exam are generally in their penultimate year of school and selected by teachers as being high performing in physics. Together with the overall differences in facility, we have investigated how the content and presentation of multiple-choice questions (MCQs affects the particular answers selected by male and female students. Differences in the patterns of responses by male and female students indicate that males and females might be modeling situations in different ways. Some strong patterns were found in the gender gaps when the questions were categorized in five broad dimensions: content, process required, difficulty, presentation, and context. Almost all questions saw male students performing better, although gender differences were relatively small for questions with a more abstract context. Male students performed significantly better on most questions with a concrete context, although notable exceptions were found, including two such questions where female students performed better. Other categories that showed consistently large gaps favoring male students include questions with projectile motion and other two-dimensional motion or forces content, and processes involving interpreting diagrams. Our results have important implications, suggesting that we should be able to reduce the gender gaps in performance on MCQ tests by changing the way information is presented and setting questions in contexts that are less likely to favor males over females. This is important as MCQ

  7. Forward lunge as a functional performance test in ACL deficient subjects: test-retest reliability

    DEFF Research Database (Denmark)

    Alkjaer, Tine; Henriksen, Marius; Dyhre-Poulsen, Poul

    2009-01-01

    The forward lunge movement may be used as a functional performance test of anterior cruciate ligament (ACL) deficient and reconstructed subjects. The purposes were 1) to determine the test-retest reliability of a forward lunge in healthy subjects and 2) to determine the required numbers...

  8. The Development of MST Test Information for the Prediction of Test Performances

    Science.gov (United States)

    Park, Ryoungsun; Kim, Jiseon; Chung, Hyewon; Dodd, Barbara G.

    2017-01-01

    The current study proposes novel methods to predict multistage testing (MST) performance without conducting simulations. This method, called MST test information, is based on analytic derivation of standard errors of ability estimates across theta levels. We compared standard errors derived analytically to the simulation results to demonstrate the…

  9. Test-Taker Characteristics and Integrated Speaking Test Performance: A Path-Analytic Study

    Science.gov (United States)

    Huang, Heng-Tsung Danny; Hung, Shao-Ting Alan; Hong, He-Ting Vivian

    2016-01-01

    This study explored the relationships among language proficiency, two selected test-taker characteristics (i.e., topical knowledge and anxiety), and integrated speaking test performance. Data collection capitalized on three sets of instruments: three integrated tasks derived from TOEFL-iBT preparation materials, the state anxiety inventory created…

  10. MOTIVATION AND PERFORMANCE IN PHYSICAL EDUCATION: AN EXPERIMENTAL TEST

    Directory of Open Access Journals (Sweden)

    Juan A. Moreno

    2010-03-01

    Full Text Available The purpose of this study was to analyse, experimentally, the relationships between motivation and performance in a lateral movement test in physical education. The study group consisted of 363 students (227 boys and 136 girls, aged between 12 and 16, who were randomly divided into three groups: an experimental group in which an incremental ability belief was induced, another experimental group in which an entity ability belief was induced, and a control group where there was no intervention. Measurements were made of situational intrinsic motivation, perceived competence in executing the task and performance. The results revealed that the incremental group reported higher scores on the situational intrinsic motivation scale. The entity group demonstrated better performance in the first test attempt than the incremental group but, in the second attempt, the performance was similar in the different groups. Perhaps the initial differences in performance disappeared because the incremental group counted on improving in the second attempt. These results are discussed in relation to the intensity with which the teacher conveys information relating to incremental ability belief of the pupil to increase intrinsic motivation and performance

  11. Stereotype Threat in Middle School: The Effects of Prior Performance on Expectancy and Test Performance

    Science.gov (United States)

    Howard, Keith E.; Anderson, Kenneth A.

    2010-01-01

    Stereotype threat research has demonstrated how presenting situational cues in a testing environment, such as raising the salience of negative stereotypes, can adversely affect test performance (Perry, Steele, & Hilliard, 2003; Steele & Aronson, 1995) and expectancy (Cadinu, Maass, Frigerio, Impagliazzo, & Latinotti, 2003; Stangor,…

  12. Performance test report for the 1000 kg melter

    Energy Technology Data Exchange (ETDEWEB)

    Eaton, W.C.

    1995-11-01

    A multiphase program was initiated in 1994 to test commercially available melter technologies for the vitrification of the low-level waste (LLW) stream from defense wastes stored in underground tanks at the Hanford Site in southeastern Washington State. Phase 1 of the melter demonstration tests using simulated LLW was completed during fiscal year 1995. This document is the 100 kg melter offgas report on testing performed by GTS Duratek Inc., in Columbia, Maryland. GTS Duratek (one of the seven vendors selected) was chosen to demonstrate Joule heated melter technology under WHC subcontract number MMI-SVV- 384215. The document contains the complete offgas report on the 100 kg melter as prepared by Parsons Engineering Science, Inc. A summary of this report is also contained in the ``GTS Duratek, Phase 1 Hanford Low-Level Waste Melter Tests: Final Report`` (WHC-SD-VI-027).

  13. Application of higher harmonic blade feathering on the OH-6A helicopter for vibration reduction

    Science.gov (United States)

    Straub, F. K.; Byrns, E. V., Jr.

    1986-01-01

    The design, implementation, and flight test results of higher harmonic blade feathering for vibration reduction on the OH-6A helicopter are described. The higher harmonic control (HHC) system superimposes fourth harmonic inputs upon the stationary swashplate. These inputs are transformed into 3P, 4P and 5P blade feathering angles. This results in modified blade loads and reduced fuselage vibrations. The primary elements of this adaptive vibration suppression system are: (1) acceleration transducers sensing the vibratory response of the fuselage; (2) a higher harmonic blade pitch actuator system; (3) a flightworthy microcomputer, incorporating the algorithm for reducing vibrations, and (4) a signal conditioning system, interfacing between the sensors, the microcomputer and the HHC actuators. The program consisted of three distinct phases. First, the HHC system was designed and implemented on the MDHC OH-6A helicopter. Then, the open loop, or manual controlled, flight tests were performed, and finally, the closed loop adaptive control system was tested. In 1983, one portion of the closed loop testing was performed, and in 1984, additional closed loop tests were conducted with improved software. With the HHC system engaged, the 4P pilot seat vibration levels were significantly lower than the baseline ON-6A levels. Moreover, the system did not adversely affect blade loads or helicopter performance. In conclusion, this successful proof of concept project demonstrated HHC to be a viable vibration suppression mechanism.

  14. Standardization in Cryogenic Insulation Systems Testing and Performance Data

    Science.gov (United States)

    Fesmire, James E.

    The close relationship between industrial energy use and cryogenics drives the need for optimized thermal insulation systems. Emerging cryofuels usage is enabled by adequate isolation of the liquid hydrogen or liquefied natural gas from the ambient environment. Thermal performance data for the total insulation system, as rendered, are essential for both engineering designs and cost-benefit decisions involving comparisons among alternatives. These data are obtained through rigorous testing with suitable apparatus and repeatable methods. Properly defined terminology, analysis, and reporting are also vital. Advances in cryogenic insulation test apparatus and methods have led to the recent addition of two new technical standards of ASTM International: C1774 - Standard Guide for Thermal Performance Testing of Cryogenic InsulationSystems and C740 - Standard Guide for Evacuated Reflective Cryogenic Insulation. Among the different techniques described in the new standards is the cylindrical boiloff calorimeter for absolute heat measurement over the full range of vacuum pressure conditions. The details of this apparatus, test method, and data analysis are given. Benchmark thermal performance data, including effective thermal conductivity (ke) and heat flux (q) for the boundary temperatures of 293 K and 77 K, are given for a number of different multilayer insulation (MLI) systems in comparison with data for other commonly-used insulation systems including perlite powder, fiberglass, polyurethane foam, and aerogels.

  15. Performance testing of supercapacitors: Important issues and uncertainties

    Science.gov (United States)

    Zhao, Jingyuan; Gao, Yinghan; Burke, Andrew F.

    2017-09-01

    Supercapacitors are a promising technology for high power energy storage, which have been used in some industrial and vehicles applications. Hence, it is important that information concerning the performance of supercapacitors be detailed and reliable so system designers can make rational decisions regarding the selection of the energy storage components. This paper is concerned with important issues and uncertainties regarding the performance testing of supercapacitors. The effect of different test procedures on the measured characteristics of both commercial and prototype supercapacitors including hybrid supercapacitors have been studied. It was found that the test procedure has a relatively minor effect on the capacitance of carbon/carbon devices and a more significant effect on the capacitance of hybrid supercapacitors. The device characteristic with the greatest uncertainty is the resistance and subsequently the claimed power capability of the device. The energy density should be measured by performing constant power discharges between appropriate voltage limits. This is particularly important in the case of hybrid supercapacitors for which the energy density is rate dependent and the simple relationship E = ½CV2 does not yield accurate estimates of the energy stored. In general, most of the important issues for testing carbon/carbon devices become more serious for hybrid supercapacitors.

  16. Performance test of single step continuous dry attrition mill

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Woo; Joung, C. Y.; Lee, Y. W.; Na, S. H.; Kim, H. S.; Kim, S

    2001-02-01

    This report describes the improvement of the two-step attrition mill to solve problems associated with its complexity and those of batch type attrition mill as well as the results of the performance test in view of the comparison. In the performance test of the improved single step continuous attrition mill, powder milling and discharge time per pass was systematically measured, and UO{sup 2}-5wt%CeO{sub 2} powder mixture, UO{sup 2}-5wt%CeO{sub 2} powder mixture with poreformer, M{sub 3}O{sub 8} powder and/or MO2 scrap were milled to compare the performance of the milling operations between the 2-step attrition mill and improved single-step attrition mill. The results of the performance test shows, in addition to its improved milling operation, an improved function in less contamination with impurities, simpler handling with easier operation and maintenance and hence, less contamination of operational location, especially when used for the operation in a confinement system, for the improved single step attrition mill compared with a batch type or continuous 2-step attrition mill.

  17. Small-Scale Tunnel Tests for Blast Performance

    Science.gov (United States)

    Felts, Joshua; Lee, Richard

    2013-06-01

    The data reported here provides a validation of a small-scale tunnel test as a tool to guide the optimization of new explosives for blast performance in tunnels. The small-scale arrangement consisted of a 2-g booster and 10-g sample mounted at the closed end of a 127-mm diameter by 4.6-m long steel tube with pressure transducers along its length. The three performance characteristics considered were peak pressure, initial energy release, and impulse. The relative performance from six explosives was compared to that from a 1.16-m diameter by 30-m long tunnel that used 2.27-kg samples. The peak pressure and impulse vs. distance did not scale between the small and larger scale tests but the relative ranking was preserved. The initial energy release was determined from a one-dimensional point-source analysis, which tracked with peak pressure vs. distance results but not with impulse suggesting additional energy released further down the tunnel for some explosives. This test is a viable tool for optimizing compositional variations for blast performance in target scenarios of similar form factor.

  18. Adaptive control of an active seat for occupant vibration reduction

    Science.gov (United States)

    Gan, Zengkang; Hillis, Andrew J.; Darling, Jocelyn

    2015-08-01

    The harmful effects on human performance and health caused by unwanted vibration from vehicle seats are of increasing concern. This paper presents an active seat system to reduce the vibration level transmitted to the seat pan and the occupants' body under low frequency periodic excitation. Firstly, the detail of the mechanical structure is given and the active seat dynamics without external load are characterized by vibration transmissibility and frequency responses under different excitation forces. Owing the nonlinear and time-varying behaviour of the proposed system, a Filtered-x least-mean-square (FXLMS) adaptive control algorithm with on-line Fast-block LMS (FBLMS) identification process is employed to manage the system operation for high vibration cancellation performance. The effectiveness of the active seat system is assessed through real-time experimental tests using different excitation profiles. The system identification results show that an accurate estimation of the secondary path is achieved by using the FBLMS on-line technique. Substantial reduction is found for cancelling periodic vibration containing single and multiple frequencies. Additionally, the robustness and stability of the control system are validated through transient switching frequency tests.

  19. 1997 Performance Testing of Multi-Metal Continuous Emissions Monitors

    Energy Technology Data Exchange (ETDEWEB)

    Sky +, Inc.

    1998-09-01

    Five prototype and two commercially available multi-metals continuous emissions monitors (CEMs) were tested in September 1997 at the Rotary Kiln Incinerator Simulator facility at the EPA National Risk Management Research Laboratory, Research Triangle Park, North Carolina. The seven CEMs were tested side by side in a long section of duct following the secondary combustion chamber of the RKIS. Two different concentrations of six toxic metals were introduced into the incinerator-approximately 15 and 75 µg/dscm of arsenic, beryllium, cadmium, chromium, lead, and mercury (We also tested for antimony but we are not reporting on it here because EPA recently dropped antimony from the list of metals addressed by the draft MACT rule). These concentrations were chosen to be close to emission standards in the draft MACT rule and the estimated Method Detection Limit (MDL) required of a CEM for regulatory compliance purposes. Results from this test show that no CEMs currently meet the performance specifications in the EPA draft MACT rule for hazardous waste incinerators. Only one of the CEMs tested was able to measure all six metals at the concentrations tested. Even so, the relative accuracy of this CEM varied between 35% and 100%, not 20% or less as required in the EPA performance specification. As a result, we conclude that no CEM is ready for long-term performance validation for compliance monitoring applications. Because sampling and measuring Hg is a recurring problem for multi-metal CEMs as well as Hg CEMs, we recommended that developers participate in a 1998 DOE-sponsored workshop to solve these and other common CEM measurement issues.

  20. Orion Launch Abort System Performance on Exploration Flight Test 1

    Science.gov (United States)

    McCauley, R.; Davidson, J.; Gonzalez, Guillermo

    2015-01-01

    This paper will present an overview of the flight test objectives and performance of the Orion Launch Abort System during Exploration Flight Test-1. Exploration Flight Test-1, the first flight test of the Orion spacecraft, was managed and led by the Orion prime contractor, Lockheed Martin, and launched atop a United Launch Alliance Delta IV Heavy rocket. This flight test was a two-orbit, high-apogee, high-energy entry, low-inclination test mission used to validate and test systems critical to crew safety. This test included the first flight test of the Launch Abort System preforming Orion nominal flight mission critical objectives. NASA is currently designing and testing the Orion Multi-Purpose Crew Vehicle (MPCV). Orion will serve as NASA's new exploration vehicle to carry astronauts to deep space destinations and safely return them to earth. The Orion spacecraft is composed of four main elements: the Launch Abort System, the Crew Module, the Service Module, and the Spacecraft Adapter (Fig. 1). The Launch Abort System (LAS) provides two functions; during nominal launches, the LAS provides protection for the Crew Module from atmospheric loads and heating during first stage flight and during emergencies provides a reliable abort capability for aborts that occur within the atmosphere. The Orion Launch Abort System (LAS) consists of an Abort Motor to provide the abort separation from the Launch Vehicle, an Attitude Control Motor to provide attitude and rate control, and a Jettison Motor for crew module to LAS separation (Fig. 2). The jettison motor is used during a nominal launch to separate the LAS from the Launch Vehicle (LV) early in the flight of the second stage when it is no longer needed for aborts and at the end of an LAS abort sequence to enable deployment of the crew module's Landing Recovery System. The LAS also provides a Boost Protective Cover fairing that shields the crew module from debris and the aero-thermal environment during ascent. Although the