WorldWideScience

Sample records for monitoring rotation speed

  1. Speed Rotating Components

    Directory of Open Access Journals (Sweden)

    S. Wittig

    1998-01-01

    Full Text Available Cooling of high speed rotating components is a typical situation found in turbomachinery as well as in automobile engines. Accurate knowledge of discharge coefficients and heat transfer of related components is essential for the high performance of the whole engine. This can be achieved by minimized cooling air flows and avoidance of hot spots. In high speed rotating clutches for example aerodynamic investigations improving heat transfer have not been considered in the past. Advanced concepts of modern plate design try to reduce thermal loads by convective cooling methods. Therefore, secondary cooling air flows have to be enhanced by an appropriate design of the rotor stator system with orifices. CFD modelling is used to improve the basic understanding of the flow field in typical geometries used in these systems.

  2. Soft initial-rotation and HΦ robust constant rotational speed control for rotational MEMS gyro

    Institute of Scientific and Technical Information of China (English)

    Ma Gaoyin; Chen Wenyuan; Cui Feng; Zhang Weiping; Wang Liqi

    2009-01-01

    A novel soft initial-rotation control system and an Hoo robust constant rotational speed controller (RCRSC) for a rotational MEMS (micro-electro-mechanical system) gyro are presented. The soft initial-rotation control system can prevent the possible tumbling down of the suspended rotor and ensure a smooth and fast initial-rotation process. After the initial-rotation process, in order to maintain the rotational speed accurately constant, the RCRSC is acquired through the mixed sensitivity design approach. Simulation results show that the actuation voltage disturbances from the internal carrier waves in the gyro is reduced by more than 15.3 dB, and the speed fluctuations due to typical external vibrations ranging from 10 Hz to 200 Hz can also be restricted to 10-3 rad/s order.

  3. Monitoring speed before and during a speed publicity campaign.

    NARCIS (Netherlands)

    Schagen, I.N.L.G. van Commandeur, J.J.F. Goldenbeld, C. & Stipdonk, H.

    2016-01-01

    Driving speeds were monitored during a period of 16 weeks encompassing different stages of an anti-speeding campaign in the Netherlands. This campaign targeted speed limit violations in built-up areas. The observation periods differed in terms of intensity and media used for the campaign. Small road

  4. Measuring Speed Of Rotation With Two Brushless Resolvers

    Science.gov (United States)

    Howard, David E.

    1995-01-01

    Speed of rotation of shaft measured by use of two brushless shaft-angle resolvers aligned so electrically and mechanically in phase with each other. Resolvers and associated circuits generate voltage proportional to speed of rotation (omega) in both magnitude and sign. Measurement principle exploits simple trigonometric identity.

  5. Monitoring speed before and during a speed publicity campaign.

    Science.gov (United States)

    van Schagen, Ingrid; Commandeur, Jacques J F; Goldenbeld, Charles; Stipdonk, Henk

    2016-12-01

    Driving speeds were monitored during a period of 16 weeks encompassing different stages of an anti-speeding campaign in the Netherlands. This campaign targeted speed limit violations in built-up areas. The observation periods differed in terms of intensity and media used for the campaign. Small road-side radars, mounted in light poles, were used and registered the speeds on 20 locations in built-up areas. Speeds of over 10 million vehicles were measured. Ten locations had a posted speed limit of 50km/h; the other ten had a posted speed limit of 30km/h. Posters were placed at half of each group of locations to remind drivers of the speed limit. The average speed on the 50km/h roads was 46.2km/h, and 36.1km/h on the 30km/h roads. The average proportions of vehicles exceeding the speed limit were 33.3% and 70.1% respectively. For the 30km/h roads, the data shows differences in speed and speeding behaviour between the six distinguished observation periods, but overall these differences cannot be logically linked to the contents of the phases and, hence, cannot be explained as an effect of the campaign. The only exception was an effect of local speed limit reminders on the 30km/h roads. This effect, however, was temporary and had disappeared within a week.

  6. Design of a high speed rotating mechanical shutter

    Energy Technology Data Exchange (ETDEWEB)

    Stowers, I.F.; Merritt, B.T.; McFann, C.B.

    1979-11-06

    A high-speed rotating shutter was designed to operate in a 10/sup -6/ Torr vacuum at the optical focus of a laser spatial filter. The shutter is basically a wheel, with a single 3 x 10-mm slot at the perimeter, which rotates with a peripheral speed of 1 km/s. The motor to drive the rotating wheel is magnetically suspended and synchronously wound. The wheel achieves a 4 ..mu..s opening time and a timing accuracy of better than 0.2 ..mu..s. (MOW)

  7. Unified Multi-speed analysis (UMA) for the condition monitoring of aero-engines

    Science.gov (United States)

    Nembhard, Adrian D.; Sinha, Jyoti K.

    2015-12-01

    For rotating machinery in which speeds and dynamics constantly change, performing vibration-based condition monitoring can be challenging. Thus, an effort is made here to develop a Unified Multi-speed fault diagnosis technique that can exploit useful vibration information available at various speeds from a rotating machine in a single analysis. Commonly applied indicators are computed from data collected from a rig at different speeds for a baseline case and different faults. Four separate analyses are performed: single speed at a single bearing, integrated features from multiple speeds at a single bearing, single speed for integrated features from multiple bearings and the proposed Unified Multi-speed analysis. The Unified Multi-speed approach produces the most conspicuous separation and isolation among the conditions tested. Observations made here suggest integration of more dynamic features available at different speeds improves the learning process of the tool which could prove useful for aero-engine condition monitoring.

  8. LIFT FORCE ON ROTATING SPHERE AT LOW REYNOLDS NUMBERS AND HIGH ROTATIONAL SPEEDS

    Institute of Scientific and Technical Information of China (English)

    由长福; 祁海鹰; 徐旭常

    2003-01-01

    The lift force on an isolated rotating sphere in a uniform flow was investigated by means of a three-dimensional numerical simulation for low Reynolds numbers (based on the sphere diameter) (Re < 68.4) and high dimensionless rotational speeds (Γ< 5). The Navier-Stokes equations in Cartesian coordinate system were solved using a finite volume formulation based on SIMPLE procedure. The accuracy of the numerical simulation was tested through a comparison with available theoretical, numerical and experimental results at low Reynolds numbers, and it was found that they were in close agreement under the above mentioned ranges of the Reynolds number and rotational speed. From a detailed computation of the flow field around a rotational sphere in extended ranges of the Reynolds number and rotational speed, the results show that, with increasing the rotational speed or decreasing the Reynolds number, the lift coefficient increases. An empirical equation more accurate than those obtained by previous studies was obtained to describe both effects of the rotational speed and Reynolds number on the lift force on a sphere. It was found in calculations that the drag coefficient is not significantly affected by the rotation of the sphere. The ratio of the lift force to the drag force, both of which act on a sphere in a uniform flow at the same time, was investigated. For a small spherical particle such as one of about 100μm in diameter, even if the rotational speed reaches about 106 revolutions per minute, the lift force can be neglected as compared with the drag force.

  9. Neural rotational speed control for wave energy converters

    Science.gov (United States)

    Amundarain, M.; Alberdi, M.; Garrido, A. J.; Garrido, I.

    2011-02-01

    Among the benefits arising from an increasing use of renewable energy are: enhanced security of energy supply, stimulation of economic growth, job creation and protection of the environment. In this context, this study analyses the performance of an oscillating water column device for wave energy conversion in function of the stalling behaviour in Wells turbines, one of the most widely used turbines in wave energy plants. For this purpose, a model of neural rotational speed control system is presented, simulated and implemented. This scheme is employed to appropriately adapt the speed of the doubly-fed induction generator coupled to the turbine according to the pressure drop entry, so as to avoid the undesired stalling behaviour. It is demonstrated that the proposed neural rotational speed control design adequately matches the desired relationship between the slip of the doubly-fed induction generator and the pressure drop input, improving the power generated by the turbine generator module.

  10. Unwinding of a carbon nanoscroll due to high speed rotation

    Directory of Open Access Journals (Sweden)

    Hang Yin

    2015-10-01

    Full Text Available A carbon nanoscroll (CNS can be formed easily by rolling a graphene sheet around a carbon nanotube (CNT [Zhang and Li, 2010, APL, 97, 081909]. When the CNS is driven by the rotary CNT to rotate at a high speed, the attractive interaction within the CNS or between the CNS and CNT is crippled by the centrifugal force on the CNS. The unwinding of CNS is triggered when the kinetic energy increment approaches to the variation of interaction energy of the system during CNS formation. Numerical experiments also indicate that the unwinding of CNS happens earlier when the CNT has a higher rotational speed or the system is at a higher temperature.

  11. Containment of high-speed rotating disk fragments

    Institute of Scientific and Technical Information of China (English)

    Hai-jun XUAN; Lu-lu LIU; Yi-ming FENG; Qing HE; Juan-juan LI

    2012-01-01

    Disk burst accidents sometimes happen in aeroengines.To avoid tragic consequences,aeroengine casings must have sufficient containment capability.Experiments and simulations need to be conducted to study the impact,distortion,and perforation caused by disk burst and which may give important clues to potential failure mechanisms.This paper presents some containment tests of high-speed rotating disk fragments,in which the original disks were burst into three equal fragments within a predetermined rotating speed range.The failure modes of the containment casing varied significantly with the thickness of the containment casing.Shearing,tearing,tensile fracture,and large plastic stretching deformation occurred in a thin-walled containment casing,while a thick-walled casing could contain disk fragments and withstand large plastic deformation.Numerical simulations were carried out to study the impact process and failure modes further.Good agreement was found between the results of the simulations and the tests.

  12. An EM Induction Hi-Speed Rotation Angular Rate Sensor.

    Science.gov (United States)

    Li, Kai; Li, Yuan; Han, Yan

    2017-03-17

    A hi-speed rotation angular rate sensor based on an electromagnetic induction signal is proposed to provide a possibility of wide range measurement of high angular rates. An angular rate sensor is designed that works on the principle of electromagnetism (EM) induction. In addition to a zero-phase detection technique, this sensor uses the feedback principle of magnetic induction coils in response to a rotating magnetic field. It solves the challenge of designing an angular rate sensor that is suitable for both low and high rotating rates. The sensor was examined for angular rate measurement accuracy in simulation tests using a rotary table. The results show that it is capable of measuring angular rates ranging from 1 rps to 100 rps, with an error within 1.8‰ of the full scale (FS). The proposed sensor is suitable to measurement applications where the rotation angular rate is widely varied, and it contributes to design technology advancements of real-time sensors measuring angular acceleration, angular rate, and angular displacement of hi-speed rotary objects.

  13. An EM Induction Hi-Speed Rotation Angular Rate Sensor

    Directory of Open Access Journals (Sweden)

    Kai Li

    2017-03-01

    Full Text Available A hi-speed rotation angular rate sensor based on an electromagnetic induction signal is proposed to provide a possibility of wide range measurement of high angular rates. An angular rate sensor is designed that works on the principle of electromagnetism (EM induction. In addition to a zero-phase detection technique, this sensor uses the feedback principle of magnetic induction coils in response to a rotating magnetic field. It solves the challenge of designing an angular rate sensor that is suitable for both low and high rotating rates. The sensor was examined for angular rate measurement accuracy in simulation tests using a rotary table. The results show that it is capable of measuring angular rates ranging from 1 rps to 100 rps, with an error within 1.8‰ of the full scale (FS. The proposed sensor is suitable to measurement applications where the rotation angular rate is widely varied, and it contributes to design technology advancements of real-time sensors measuring angular acceleration, angular rate, and angular displacement of hi-speed rotary objects.

  14. Effect of gravity level fluctuations for rotating fluids in high and low rotating speeds

    Science.gov (United States)

    Hung, R. J.; Tsao, Y. D.; Hong, B. B.; Leslie, F. W.

    1989-01-01

    Time-dependent evolutions of the profile of the free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations of the dynamics of bubble shapes have been carried out with sinusoidal-function vibration of the gravity environment at high and low cylinder speeds.

  15. Research on motor rotational speed measurement in regenerative braking system of electric vehicle

    Science.gov (United States)

    Pan, Chaofeng; Chen, Liao; Chen, Long; Jiang, Haobin; Li, Zhongxing; Wang, Shaohua

    2016-01-01

    Rotational speed signals acquisition and processing techniques are widely used in rotational machinery. In order to realized precise and real-time control of motor drive and regenerative braking process, rotational speed measurement techniques are needed in electric vehicles. Obtaining accurate motor rotational speed signal will contribute to the regenerative braking force control steadily and realized higher energy recovery rate. This paper aims to develop a method that provides instantaneous speed information in the form of motor rotation. It addresses principles of motor rotational speed measurement in the regenerative braking systems of electric vehicle firstly. The paper then presents ideal and actual Hall position sensor signals characteristics, the relation between the motor rotational speed and the Hall position sensor signals is revealed. Finally, Hall position sensor signals conditioning and processing circuit and program for motor rotational speed measurement have been carried out based on measurement error analysis.

  16. Composite reinforced metallic cylinder for? high-speed rotation

    Science.gov (United States)

    Pradhan, Sahadev, , Dr.

    2017-01-01

    The objective of the present study is to design and development of the composite reinforced thin metallic cylinder to increase the peripheral speed significantly and thereby? improve the separation performance in a centrifugal gas separation processes through? proper optimization of the internal parameters. According to Dirac equation (Cohen? (1951)), the maximum separative work for a centrifugal gas separation process increase? with 4th power of the peripheral speed. Therefore, it has been intended to reinforce the? metallic cylinder with composites (carbon fibers: T-700 and T- 1000 grade with suitable? epoxy resin) to increase the stiffness and hoop stress so that the peripheral speed can? be increased significantly, and thereby enhance the separative output. Here, we have developed the mathematical model to investigate the elastic stresses of? a laminated cylinder subjected to mechanical, thermal and thermo-mechanical loading? A detailed analysis is carried out to underline the basic hypothesis of each formulation? Further, we evaluate the steady state creep response of the rotating cylinder and analyze? the stresses and strain rates in the cylinder.

  17. Characterization of deflagrating munitions by rotating prism high speed photography

    Science.gov (United States)

    Kinsey, Trevor J.; Bussell, Tim J.; Chick, Michael C.

    1992-08-01

    We report on the use of a rotating prism high speed camera for determining the characteristics of a munition undergoing rapid deflagration in field experiments. The technique has been applied to study the controlled deflagration of Composition B filled 105 mm shell and 81 mm mortar bombs as representative thick and thin cased munitions respectively; however the report is mostly illustrated with results from the study on 105 mm shell. The deflagration event has been characterized in terms of case expansion rate, initial fragment velocity, time to case burst, time to reaction from the nose end and the deflagration rate of the filling. Products escaping from the fracturing case eventually obscured the image which limited the extent of the measurement.

  18. Allosteric Regulation of the Rotational Speed in a Light-Driven Molecular Motor

    NARCIS (Netherlands)

    Faulkner, Adele; van Leeuwen, Thomas; Feringa, Ben L; Wezenberg, Sander J

    2016-01-01

    The rotational speed of an overcrowded alkene-based molecular rotary motor, having an integrated 4,5-diazafluorenyl coordination motif, can be regulated allosterically via the binding of metal ions. DFT calculations have been used to predict the relative speed of rotation of three different (i.e. zi

  19. Note: Lossless laser beam combiner employing a high-speed rotating half-wave plate

    Science.gov (United States)

    Yatsuka, E.; Yamamoto, T.; Hatae, T.; Torimoto, K.; Itami, K.

    2017-07-01

    We have developed a laser beam combiner employing a high-speed rotating half-wave plate based on the specific requirements of the Thomson scattering measurement systems in the ITER. The polarization extinction ratio of the output beam may exceed 1000 and was maintained for more than 1 h via feedback control of the half-wave plate rotation speed. The pointing fluctuations introduced by rotating the half-wave plate were in the order of microradians. The high-speed rotating half-wave plate provides a lossless means of combining laser beams together with stable beam pointing.

  20. Note: Lossless laser beam combiner employing a high-speed rotating half-wave plate.

    Science.gov (United States)

    Yatsuka, E; Yamamoto, T; Hatae, T; Torimoto, K; Itami, K

    2017-07-01

    We have developed a laser beam combiner employing a high-speed rotating half-wave plate based on the specific requirements of the Thomson scattering measurement systems in the ITER. The polarization extinction ratio of the output beam may exceed 1000 and was maintained for more than 1 h via feedback control of the half-wave plate rotation speed. The pointing fluctuations introduced by rotating the half-wave plate were in the order of microradians. The high-speed rotating half-wave plate provides a lossless means of combining laser beams together with stable beam pointing.

  1. Centrifugally activated bearing for high-speed rotating machinery

    Science.gov (United States)

    Post, Richard F.

    1994-01-01

    A centrifugally activated bearing is disclosed. The bearing includes an annular member that extends laterally and radially from a central axis. A rotating member that rotates about the central axis relative to the annular member is also included. The rotating member has an interior chamber that surrounds the central axis and in which the annular member is suspended. Furthermore, the interior chamber has a concave shape for retaining a lubricant therein while the rotating member is at rest and for retaining a lubricant therein while the rotating member is rotating. The concave shape is such that while the rotating member is rotating a centrifugal force causes a lubricant to be forced away from the central axis to form a cylindrical surface having an axis collinear with the central axis. This centrifugally displaced lubricant provides restoring forces to counteract lateral displacement during operation.

  2. The influence of global warming in Earth rotation speed

    Directory of Open Access Journals (Sweden)

    R. Abarca del Rio

    Full Text Available The tendency of the atmospheric angular momentum (AAM is investigated using a 49-year set of monthly AAM data for the period January 1949-December 1997. This data set is constructed with zonal wind values from the reanalyses of NCEP/NCAR, used in conjunction with a variety of operationally produced AAM time series with different independent sources and lengths over 1976-1997. In all the analyzed AAM series the linear trend is found to be positive. Since the angular momentum of the atmosphere-earth system is conserved this corresponds to a net loss of angular momentum by the solid earth, therefore decreasing the Earth rotation speed and increasing the length of day (LOD. The AAM rise is significant to the budget of angular momentum of the global atmosphere-earth system; its value in milliseconds/century (ms/cy is +0.56 ms/cy, corresponding to one-third of the estimated increase in LOD (+1.7 ms/cy. The major contribution to this secular trend in AAM comes from the equatorial Tropopause. This is consistent with results from a previous study using a simplified aqua-planet model to investigate the AAM variations due to near equatorial warming conditions. During the same time interval, 1949-1997, the global marine + land-surface temperature increases by about 0.79 °C/cy, showing a linear correspondence between surface temperature increase and global AAM of about 0.07 ms per 0.1 °C. These results imply that atmospheric angular momentum may be used as an independent index of the global atmosphere's dynamical response to the greenhouse forcing, and as such, the length of day may be used as an indirect indicator of global warming.

    Key words. Meteorology and atmospheric dynamics (general circulation · Geodesy

  3. On the experimental prediction of the stability threshold speed caused by rotating damping

    Science.gov (United States)

    Vervisch, B.; Derammelaere, S.; Stockman, K.; De Baets, P.; Loccufier, M.

    2016-08-01

    An ever increasing demand for lighter rotating machinery and higher operating speeds results in a raised probability of instabilities. Rotating damping is one of the reasons, instability occurs. Rotating damping, or rotor internal damping, is the damping related to all rotating parts while non-rotating damping appearing in the non-rotating parts. The present study describes a rotating setup, designed to investigate rotating damping experimentally. An efficient experimental procedure is presented to predict the stability threshold of a rotating machine. The setup consists of a long thin shaft with a disk in the middle and clamped boundary conditions. The goal is to extract the system poles as a function of the rotating speed. The real parts of these poles are used to construct the decay rate plot, which is an indication for the stability. The efficiency of the experimental procedure relies on the model chosen for the rotating shaft. It is shown that the shaft behavior can be approximated by a single degree of freedom model that incorporates a speed dependent damping. As such low measurement effort and only one randomly chosen measurement location are needed to construct the decay rate plot. As an excitation, an automated impact hammer is used and the response is measured by eddy current probes. The proposed method yields a reliable prediction of the stability threshold speed which is validated through measurements.

  4. INVESTIGATION OF THE INFLUENCE OF MOLD ROTATIONAL SPEED ON THE CAST WALL THICKNESS IN THE ROTATIONAL MOLDING PROCESS

    Directory of Open Access Journals (Sweden)

    Tomasz Jachowicz

    2013-09-01

    Full Text Available This paper presents the rotational molding process. The general principles of this polymer processing technology have been described. The main applications have been introduced and leading advantages and typical disadvantages of rotational molding process have been discussed. Based on the conducted experimental tests, the influence of changing one selected technological parameter, which characterized rotational molding process, on selected geometrical features of the polymer cast has been determined. Rotational mold’s speed around axes was changed and a thickness of cast walls has been measured. Laboratory test stand, processing properties of polymer, also test program and experimental test methodology have been described.

  5. Evaluation of the lubrication mechanism at various rotation speeds and granule filling levels in a container mixer using a thermal effusivity sensor.

    Science.gov (United States)

    Uchiyama, Jumpei; Aoki, Shigeru

    2015-01-01

    To research the detailed mechanism of the lubrication process using the thermal effusivity sensor, the relationships of the lubrication progress with the pattern of powder flow, the rotation speed and the filling level were investigated. The thermal effusivity profile was studied as a function of the number of rotations at various rotation speeds. It was observed that at lower rotation speeds, the profiles of the lubrication progress were almost the same, regardless of the rotation speed. In this region, the highest speed was defined as the critical rotation speed (CRS), which was found to be one of the important factors. The CRS had close relations with avalanche flow in the blender. The first and the second phases were observed in the lubrication process. The first phase was influenced by the CRS and the filling level in the blender. The second phase was influenced by the rotation speed. The mechanism of two-phase process was proposed as a macro progression of the dispersion of the lubricant (first phase) and micro progression of the coating of the powder particles with lubricant (second phase). The accurate monitoring by the thermal effusivity sensor was able to help a better understanding in the lubrication process.

  6. INTELLIGENT TOOL CONDITION MONITORING IN HIGH-SPEED ...

    African Journals Online (AJOL)

    MR PRINCE

    work model has been developed for on-line condition monitoring of tool wear in high-speed ... degraded behaviours in wire electrical dis- ... mathematical models such as regression (Lin et ... an 11 kW Computer Numerical Controlled.

  7. High Rotation Speed Friction Stir Welding for 2014 Aluminum Alloy Thin Sheets

    Science.gov (United States)

    Chen, Shujin; Zhou, Yang; Xue, Junrong; Ni, Ruiyang; Guo, Yue; Dong, Jianghui

    2017-03-01

    In this study, 2014 aluminum alloy sheets with 1 mm thickness are welded successfully by friction stir welding (FSW) robot under the condition of high rotation speed. When the high rotation speed of 10,000-16,500 rpm is applied, the lower axial pressure (less than 200 N) is obtained, which reduces stiffness requirements for equipment. Welding deformation is inevitable because high rotation speed can easily result in rapid heating rate and uneven heat input. The welding distortion caused by two cooling methods is measured, respectively, by laser range finder. The experimental results show that the welding distortion is smaller under the condition of water cooling. When the rotation speed is up to 15,000 rpm and welding speed 50-170 mm/min, the whole welding process is controllable. Under the higher rotation speed condition, the welding defects disappear gradually and more stable mechanical properties can be obtained up to 75% of base metal (ω = 16,000 rpm, ν = 110 mm/min). The results of different welding parameters demonstrate that the high rotation speed can increase material mixing and reduce the axial force (z force), and it can benefit lightweight sheet welding by using FSW robot.

  8. High Rotation Speed Friction Stir Welding for 2014 Aluminum Alloy Thin Sheets

    Science.gov (United States)

    Chen, Shujin; Zhou, Yang; Xue, Junrong; Ni, Ruiyang; Guo, Yue; Dong, Jianghui

    2017-02-01

    In this study, 2014 aluminum alloy sheets with 1 mm thickness are welded successfully by friction stir welding (FSW) robot under the condition of high rotation speed. When the high rotation speed of 10,000-16,500 rpm is applied, the lower axial pressure (less than 200 N) is obtained, which reduces stiffness requirements for equipment. Welding deformation is inevitable because high rotation speed can easily result in rapid heating rate and uneven heat input. The welding distortion caused by two cooling methods is measured, respectively, by laser range finder. The experimental results show that the welding distortion is smaller under the condition of water cooling. When the rotation speed is up to 15,000 rpm and welding speed 50-170 mm/min, the whole welding process is controllable. Under the higher rotation speed condition, the welding defects disappear gradually and more stable mechanical properties can be obtained up to 75% of base metal (ω = 16,000 rpm, ν = 110 mm/min). The results of different welding parameters demonstrate that the high rotation speed can increase material mixing and reduce the axial force (z force), and it can benefit lightweight sheet welding by using FSW robot.

  9. Proactive condition monitoring of low-speed machines

    CERN Document Server

    Stamboliska, Zhaklina; Moczko, Przemyslaw

    2015-01-01

    This book broadens readers’ understanding of proactive condition monitoring of low-speed machines in heavy industries. It focuses on why low-speed machines are different than others and how maintenance of these machines should be implemented with particular attention. The authors explain the best available monitoring techniques for various equipment and the principle of how to get proactive information from each technique. They further put forward possible strategies for application of FEM for detection of faults and technical assessment of machinery. Implementation phases are described and industrial case-studies of proactive condition monitoring are included. Proactive Condition Monitoring of Low-Speed Machines is an essential resource for engineers and technical managers across a range of industries as well as design engineers working in industrial product development. This book also: ·         Explains the practice of proactive condition monitoring and illustrates implementation phases ·   ...

  10. Numerical Investigation on a Prototype Centrifugal Pump Subjected to Fluctuating Rotational Speed

    Directory of Open Access Journals (Sweden)

    Yu-Liang Zhang

    2014-01-01

    Full Text Available The rotational speed of pumps often encounters fluctuation in engineering for some reasons. In this paper, in order to study the transient response characteristic of a prototype centrifugal pump subjected to fluctuating rotational speed, a closed-loop pipe system including the pump is built to accomplish unsteady flow calculations in which the boundary conditions at the inlet and the outlet of the pump are not required to be set. The external performance results show that the head’s responsiveness to the fluctuating rotational speed is very good, while the flow rate’s responsiveness is slightly delayed. The variation tendencies of the static pressures at the inlet and the outlet of the pump are almost completely opposite, wherein the variation tendency of the static pressure at the outlet is identical with that of the rotational speed. The intensity of the turbulence energy in each impeller channel is relatively uniform in the transient flow calculations, while, in the quasi-steady flow calculation, it becomes weaker in a channel closed to the volute tongue. The nondimensional flow rate and head coefficients are dependent on the rotational speed, and their variation tendencies are opposite to that of the fluctuating rotational speed as a whole.

  11. Monitoring Vibration of A Model of Rotating Machine

    Directory of Open Access Journals (Sweden)

    Arko Djajadi

    2012-03-01

    Full Text Available Mechanical movement or motion of a rotating machine normally causes additional vibration. A vibration sensing device must be added to constantly monitor vibration level of the system having a rotating machine, since the vibration frequency and amplitude cannot be measured quantitatively by only sight or touch. If the vibration signals from the machine have a lot of noise, there are possibilities that the rotating machine has defects that can lead to failure. In this experimental research project, a vibration structure is constructed in a scaled model to simulate vibration and to monitor system performance in term of vibration level in case of rotation with balanced and unbalanced condition. In this scaled model, the output signal of the vibration sensor is processed in a microcontroller and then transferred to a computer via a serial communication medium, and plotted on the screen with data plotter software developed using C language. The signal waveform of the vibration is displayed to allow further analysis of the vibration. Vibration level monitor can be set in the microcontroller to allow shutdown of the rotating machine in case of excessive vibration to protect the rotating machine from further damage. Experiment results show the agreement with theory that unbalance condition on a rotating machine can lead to larger vibration amplitude compared to balance condition. Adding and reducing the mass for balancing can be performed to obtain lower vibration level. 

  12. The Response of a Low Speed Compressor on Rotating Inlet Distortion

    Institute of Scientific and Technical Information of China (English)

    Chaoqun NIE; Jingxuan ZHANG; Zhiting TONG; Hongwu ZHANG

    2006-01-01

    In multi-spool engines,the downstream compressor experiences a rotating inlet distortion if rotating stall occurs in upstream compressor,which may induce the instability of the whole compressor.In this paper,the compressor dynamic behavior is the major focus.The experiment was carried out on a single-stage low-speed axial-flow compressor.A rotating distortion generator equipped with different distortion sector(s) was designed to produce different rotating inlet distortion clockwise or counterclockwise with up to 100% of the compressor design speed.The distortion sector can be installed single or in some combination such as four sectors together.Three types of distortion sector/combination are used in the research work,which are single 30 degree sector,four 30 degree sectors and single 120 degree sector.It is found that the total pressure loss caused by rotating sector(s) increases when the distortion speed rises.For co-rotating distortions,all the three types of inlet distortion exhibited a peak in stall margin degradation when the distortion speed corresponded to roughly 50% of rotor speed.The two-dimensional numerical simulations of the compressor flow field clearly show the propagation of the disturbances trigged by the distortion sector(s).

  13. Design and Realization of Rotating Machinery Conditions Monitoring System Based on Labview

    Science.gov (United States)

    Fan, Qiyuan

    Nonlinear dynamic analysis of rotating machinery system has always been the hot spot of the rotational dynamics research. This article sets up a rotating machinery condition monitoring system to realize the measurement of system dynamic characteristic parameters based on NI(National Instruments) virtual instruments technology. The measurement of vibration signal of rotating machinery system is achieved by using NI company general data acquisition module of NI company. Meanwhile, by analyzing and processing the acquired data using Labview 2012, the dynamic characteristics, such as .the speed of the rotating machinery system, the axis trajectory, spectrum parameters, are attained. The measurement results show that the rotating machinery condition monitoring system based on Labview is easy to operate, easy to realize the function extension and maintenance, and that it can be used in the industrial engineering projects with rotation characteristics. Labview as the development tools used by virtual instrument function, is very powerful data acquisition software products support is one of the features of it, so using Labview programming and data acquisition is simple and convenient [1].

  14. A stable high-speed rotational transmission system based on nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Kun, E-mail: caikun1978@163.com [College of Water Resources and Architectural Engineering, Northwest A and F University, Yangling 712100 (China); State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024 (China); Yin, Hang; Wei, Ning [College of Water Resources and Architectural Engineering, Northwest A and F University, Yangling 712100 (China); Chen, Zhen [State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024 (China); Department of Civil and Environmental Engineering, University of Missouri, Columbia, Missouri 65211-2200 (United States); Shi, Jiao [Department of Civil and Environmental Engineering, University of Missouri, Columbia, Missouri 65211-2200 (United States)

    2015-01-12

    A stable rotational transmission system is designed with a single-walled carbon nanotube (SWCNT)-based motor and double-walled carbon nanotubes (DWCNTs)-based bearing. The system response is investigated using molecular dynamics (MD) simulation. It is found that the rotating motor can actuate the rotation of the inner tube in bearing because of the attraction between the two adjacent coaxial ends of motor and rotor (the inner tube in bearing). To have a stable nanostructure, each carbon atom on the adjacent ends of motor and rotor is bonded with a hydrogen atom. To obtain a stable high-speed rotational transmission system, both an armchair and a zigzag model are used in MD simulation. In each model, the motor with different diameters and rotational speeds is employed to examine the rotational transmission of corresponding DWCNTs. It is demonstrated that the long range van der Waals interaction between the adjacent ends of motor and rotor leads to a stable configuration of the adjacent ends, and further leads to a stable rotation of rotor when driven by a high-speed motor. As compared with the armchair model, the rotor in the zigzag model could reach a stable rotation mode much easier.

  15. A stable high-speed rotational transmission system based on nanotubes

    Science.gov (United States)

    Cai, Kun; Yin, Hang; Wei, Ning; Chen, Zhen; Shi, Jiao

    2015-01-01

    A stable rotational transmission system is designed with a single-walled carbon nanotube (SWCNT)-based motor and double-walled carbon nanotubes (DWCNTs)-based bearing. The system response is investigated using molecular dynamics (MD) simulation. It is found that the rotating motor can actuate the rotation of the inner tube in bearing because of the attraction between the two adjacent coaxial ends of motor and rotor (the inner tube in bearing). To have a stable nanostructure, each carbon atom on the adjacent ends of motor and rotor is bonded with a hydrogen atom. To obtain a stable high-speed rotational transmission system, both an armchair and a zigzag model are used in MD simulation. In each model, the motor with different diameters and rotational speeds is employed to examine the rotational transmission of corresponding DWCNTs. It is demonstrated that the long range van der Waals interaction between the adjacent ends of motor and rotor leads to a stable configuration of the adjacent ends, and further leads to a stable rotation of rotor when driven by a high-speed motor. As compared with the armchair model, the rotor in the zigzag model could reach a stable rotation mode much easier.

  16. Faults Identification and Corrective Actions in Rotating Machinery at Rated Speed

    Directory of Open Access Journals (Sweden)

    Nicolò Bachschmid

    2006-01-01

    Full Text Available Malfunction identification in rotor systems by means of a model based approach in the frequency domain during long lasting speed transients (coast-down procedures in large turbo-generators, where a huge amount of vibration data at different rotating speeds is usually collected, has proved to be very effective. This paper explores the possibility to adapt this method to the situation when the vibration data are available at one rotating speed only, which in real machines is generally the normal operating speed. It results that single speed fault identification can be successful, but does not allow to discriminate between different malfunctions that generate similar symptoms. Neverthless the identification results can be used to define corrective balancing masses.

  17. Transverse nonlinear vibrations of a circular spinning disk with a varying rotating speed

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We analyze the transverse nonlinear vibrations of a rotating flexible disk subjected to a rotating point force with a periodically varying rotating speed. Based on Hamilton’s principle, the nonlinear governing equations of motion (coupled equations among the radial, tangential and transverse displacements) are derived for the rotating flexible disk. When the in-plane inertia is ignored and a stress function is introduced, the three nonlinearly coupled partial differential equations are reduced to two nonlinearly coupled partial differential equations. According to Galerkin’s approach, a four-degree-of-freedom nonlinear system governing the weakly split resonant modes is derived. The resonant case considered here is 1:1:2:2 internal resonance and a critical speed resonance. The primary parametric resonance for the first-order sin and cos modes and the fundamental parametric resonance for the second-order sin and cos modes are also considered. The method of multiple scales is used to obtain a set of eight-dimensional nonlinear averaged equations. Based on the averaged equations, using numerical simulations, the influence of different parameters on the nonlinear vibrations of the spinning disk is detected. It is concluded that there exist complicated nonlinear behaviors including the periodic, period-n and multi-pulse type chaotic motions for the spinning disk with a varying rotating speed. It is also found that among all parameters, the damping and excitation have great influence on the nonlinear responses of the spinning disk with a varying rotating speed.

  18. Advanced Machine learning Algorithm Application for Rotating Machine Health Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kanemoto, Shigeru; Watanabe, Masaya [The University of Aizu, Aizuwakamatsu (Japan); Yusa, Noritaka [Tohoku University, Sendai (Japan)

    2014-08-15

    The present paper tries to evaluate the applicability of conventional sound analysis techniques and modern machine learning algorithms to rotating machine health monitoring. These techniques include support vector machine, deep leaning neural network, etc. The inner ring defect and misalignment anomaly sound data measured by a rotating machine mockup test facility are used to verify the above various kinds of algorithms. Although we cannot find remarkable difference of anomaly discrimination performance, some methods give us the very interesting eigen patterns corresponding to normal and abnormal states. These results will be useful for future more sensitive and robust anomaly monitoring technology.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-27

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

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

    Science.gov (United States)

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

    2017-09-01

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

  1. A Soft Sensor Development for the Rotational Speed Measurement of an Electric Propeller

    Directory of Open Access Journals (Sweden)

    Fengchao Ye

    2016-12-01

    Full Text Available In recent decades, micro air vehicles driven by electric propellers have become a hot topic, and developed quickly. The performance of the vehicles depends on the rotational speed of propellers, thus, improving the accuracy of rotational speed measurement is beneficial to the vehicle’s performance. This paper presents the development of a soft sensor for the rotational speed measurement of an electric propeller. An adaptive learning algorithm is derived for the soft sensor by using Popov hyperstability theory, based on which a one-step-delay adaptive learning algorithm is further proposed to solve the implementation problem of the soft sensor. It is important to note that only the input signal and the commutation instant of the motor are employed as inputs in the algorithm, which makes it possible to be easily implemented in real-time. The experimental test results have demonstrated the learning performance and the accuracy of the soft sensor.

  2. A Fuzzy Control System of Turbine Rotate Speed and Power for a Power Plant Simulator

    Institute of Scientific and Technical Information of China (English)

    史小平; 王子才

    2002-01-01

    In this paper, a fuzzy control system of turbine rotate speed and power for a power plant simulator is designed. Rotate speed and power control is a rather important technique in a thermal power plant, because the rotate speed of the turbine rotor and the power of the generator must be enhanced gradually in order to prevent the relative expansion of the cylinder from increasing abruptly. The two parameters of a turbine used to be controlled manually or manual-automatically. To improve the control quality and the automation level, a fuzzy control method is developed for apower plant simulator to fit the DCS (Distributed Control System). The results of practical debugging on the simulator are shown in the paper to demonstrate the correctness and effectiveness of the presented fuzzy control law.

  3. An Approximate Solution for Flow between Two Disks Rotating about Distinct Axes at Different Speeds

    Directory of Open Access Journals (Sweden)

    H. Volkan Ersoy

    2007-01-01

    Full Text Available The flow of a linearly viscous fluid between two disks rotating about two distinct vertical axes is studied. An approximate analytical solution is obtained by taking into account the case of rotation with a small angular velocity difference. It is shown how the velocity components depend on the position, the Reynolds number, the eccentricity, the ratio of angular speeds of the disks, and the parameters satisfying the conditions u=0 and ν=0 in midplane.

  4. Modeling Torque Versus Speed, Shot Noise, and Rotational Diffusion of the Bacterial Flagellar Motor

    Science.gov (United States)

    Mora, Thierry; Yu, Howard; Wingreen, Ned S.

    2009-12-01

    We present a minimal physical model for the flagellar motor that enables bacteria to swim. Our model explains the experimentally measured torque-speed relationship of the proton-driven E. coli motor at various pH and temperature conditions. In particular, the dramatic drop of torque at high rotation speeds (the “knee”) is shown to arise from saturation of the proton flux. Moreover, we show that shot noise in the proton current dominates the diffusion of motor rotation at low loads. This suggests a new way to probe the discreteness of the energy source, analogous to measurements of charge quantization in superconducting tunnel junctions.

  5. Modeling torque versus speed, shot noise, and rotational diffusion of the bacterial flagellar motor.

    Science.gov (United States)

    Mora, Thierry; Yu, Howard; Wingreen, Ned S

    2009-12-11

    We present a minimal physical model for the flagellar motor that enables bacteria to swim. Our model explains the experimentally measured torque-speed relationship of the proton-driven E. coli motor at various pH and temperature conditions. In particular, the dramatic drop of torque at high rotation speeds (the "knee") is shown to arise from saturation of the proton flux. Moreover, we show that shot noise in the proton current dominates the diffusion of motor rotation at low loads. This suggests a new way to probe the discreteness of the energy source, analogous to measurements of charge quantization in superconducting tunnel junctions.

  6. A novel method for sensing rotational speed, linear displacement and current using superconducting BPSCCO magnetic sensor

    Indian Academy of Sciences (India)

    T K Dey; A Ray; S K Ghatak

    2002-11-01

    For many decades, magnetic sensors have been of great assistance to mankind in variety of functions that include simple compass based navigational systems to devices that monitor the invisible biological activities. In industries magnetic sensors are in great demand for control and measurement of linear and rotary position sensing etc, because of its non destructive and contact less way of detection. Consequently, newer, smarter and cheaper materials are continuously being explored to suit the varied needs of technological requirements. In the present communication, the characteristics of a magnetic sensor, based on the non linear electromagnetic response of the weak links present in the polycrystalline BPSCCO superconductor are reported. The second harmonic response of sintered superconducting BPSCCO pellet in an alternating magnetic field at 40 kHz and 77 K being a strong linear function of low d.c. magnetic field has been utilized for the development of highly sensitive magnetic field sensors. The noise limited resolution of the sensor is found to be 3.16 × 10–9 T/√ Hz for $H_{a.c.}$ = 16 Oe and frequency 40 kHz. We further demonstrate that such HTSC based magnetic sensors are capable of sensing the rotational speed, small displacement and direct current with good resolution. The experimental methods and results obtained are discussed.

  7. EXPERIMENTAL INVESTIGATION OF ROTATING STALL FOR A LOW-SPEED CENTRIFUGAL COMPRESSOR

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiaocheng; GUO Qiang; DU Zhaohui; CHEN Hua; ZHAO Yan

    2008-01-01

    Unsteady flows and rotating stall of a low-speed centrifugal compressor are investigated by measuring vaneless diffuser wall static pressure fluctuation and internal flow fields at different small flow fluxes. During the experiment, firstly the real time static pressure fluctuations on the vaneless diffuser shroud at different circumferential and radial position were acquired by high-frequency dynamic pressure transducers. Discrete Fourier transformation analysis and cross-correlation analysis were applied to the experimental results to ascertain the rotating stall beginning operation conditions and stall cells numbers and rotating speed. Secondly, the vaneless diffuser inlet flow angle distribution along diffuser width direction was acquired by single hotwire, which was compared with SENOO's analysis results. At last, the internal flow fields of the centrifugal compressor were investigated with a particle image velocimetry (PIV) system at different small flow fluxes. The flow field development of vaneless diffuser and blade flow passage are given at rotating stall conditions. The experiments enrich the understanding of rotating stall flow phenomenon of the low-speed centrifugal compressor and provide full experiment data for designing high performance centrifugal compressor.

  8. DETERMINATION OF CRITICAL ROTATIONAL SPEED OF CIRCULAR SAWS FROM NATURAL FREQUENCIES OF ANNULAR PLATE WITH ANALOGOUS DIMENSIONS

    Directory of Open Access Journals (Sweden)

    Ante Skoblar

    2016-03-01

    Full Text Available It is suitable to reduce thickness of circular saw when trying to enhance usability of wood raw material, but reducing thickness also causes reduction of permissible rotational speed which reduces sawing speed. If one increase circular saw rotational speed over permissible one the quality of machined surfaces will reduce because of enhanced vibrations. Permissible rotational speed can be calculated from critical rotational speed which can be defined from natural frequencies of the saw. In this article critical rotational speeds of standard clamped saws (with flat disk surface and without slots are calculated by using finite element method and classical theory of thin plates on annular plates. Mode shapes and natural frequencies of annular plates are determined by using Bessel functions and by using polynomial functions. Obtained results suggest that standard clamped circular saws without slots and with relatively small teeth can be determined from classical theory of thin plates for annular plates with accuracy depending on clamping ratio.

  9. A ball-bearing structured triboelectric nanogenerator for nondestructive damage and rotating speed measurement

    Science.gov (United States)

    Li, Xiao Hui; Han, Chang Bao; Jiang, Tao; Zhang, Chi; Wang, Zhong Lin

    2016-02-01

    A ball-bearing structure based triboelectric nanogenerator (B-TENG) with interdigitative-electrodes was developed that can not only collect energy from rotational kinetic energy, but also serve as a self-powered and multifunctional sensor. The B-TENG relies on the rolling electrification between PTFE balls on Cu interdigitative-electrodes, which delivers an open-circuit voltage of ∼40 V and a short-circuit current of ∼1.2 μA at a rotating speed of 300 rpm for 4 mm PTFE balls. Using the output signals of B-TENG, a nondestructive detection for the damage of PTFE balls was realized without demounting the bearing. Besides, based on the periodic signals produced from B-TENG, the rotation speed of ball-bearing can be obtained according to the time difference between several cycles.

  10. Thermodynamics of a dry atmosphere at different surface exchange rates and rotation speeds

    CERN Document Server

    Pascale, Salvatore; Lucarini, Valerio; Wang, Yixiong

    2012-01-01

    We study the combined effect of the rotation speed {\\Omega} and of the surface exchange rate - quantified by a surface turbulent relaxation timescale {\\tau} - on the dissipative properties of an Earth-like dry atmosphere. The rotation speed {\\Omega} is varied between one tenth and eight times that of the Earth {\\Omega} \\approx 7.29\\cdot10-5 rad-1 and {\\tau} from 45 minutes to 500 days. We study the circulation regimes induced by such parametric variations through two key dimensionless parameters, the thermal Rossby number Ro and the frictional dimensionless number Ff. An extensive analysis is performed by using nonequilibrium thermodynamics diagnostic tools such as material entropy production, efficiency, meridional heat transport and kinetic energy dissipation. The thermal dissipation associated with the sensible heat flux is found to depend mainly on the surface properties and to be almost independent from the rotation rate, whereas the dissipation of kinetic energy depends in a nontrivial way on both. Slow...

  11. Network Based Real Time Condition Monitoring of Rotating Machinery

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This paper presents the development of a network based real time condition monitoring system of rotating machinery. The system is built up in a double net structure consisting of local net (including client and server) and intranet. The client serves as a field data collector and processor that samples the vibration signals and process parameters of a machine monitored in the net and processes the sampled data. The data collected by the client are transmitted to the server that processes the data further and provides the results of the diagnosis of each machine to any distant terminals through intranet or internet. Such a structure of the monitoring system is advantageous in safety, reliability and reasonably shares the existing net resources. In order to ensure real time transmission of the data, two procedures of data transmission, virtual channel and data pool, are developed and applied in the monitoring system. The experimental results show that the monitoring system works well and is suitable to monitor a large group of rotating machines.

  12. Instantaneous angular speed monitoring of gearboxes under non-cyclic stationary load conditions

    Science.gov (United States)

    Stander, C. J.; Heyns, P. S.

    2005-07-01

    Recent developments in the condition monitoring and asset management market have led to the commercialisation of online vibration-monitoring systems. These systems are primarily utilised to monitor large mineral mining equipment such as draglines, continuous miners and hydraulic shovels. Online monitoring systems make diagnostic information continuously available for asset management, production outsourcing and maintenance alliances with equipment manufacturers. However, most online vibration-monitoring systems are based on conventional vibration-monitoring technologies, which are prone to giving false equipment deterioration warnings on gears that operate under fluctuating load conditions. A simplified mathematical model of a gear system was developed to illustrate the feasibility of monitoring the instantaneous angular speed (IAS) as a means of monitoring the condition of gears that are subjected to fluctuating load conditions. A distinction is made between cyclic stationary load modulation and non-cyclic stationary load modulation. It is shown that rotation domain averaging will suppress the modulation caused by non-cyclic stationary load conditions but will not suppress the modulation caused by cyclic stationary load conditions. An experimental investigation on a test rig indicated that the IAS of a gear shaft could be monitored with a conventional shaft encoder to indicate a deteriorating gear fault condition.

  13. Fibre Optic System for Monitoring Rotational Seismic Phenomena

    Directory of Open Access Journals (Sweden)

    Anna Kurzych

    2014-03-01

    Full Text Available We outline the development and the application in a field test of the Autonomous Fibre-Optic Rotational Seismograph (AFORS, which utilizes the Sagnac effect for a direct measurement of the seismic-origin rotations of the ground. The main advantage of AFORS is its complete insensitivity to linear motions, as well as a direct measurement of rotational components emitted during seismic events. The presented system contains a special autonomous signal processing unit which optimizes its operation for the measurement of rotation motions, whereas the applied telemetric system based on the Internet allows for an AFORS remote control. The laboratory investigation of such two devices indicated that they keep an accuracy of no less than 5.1 × 10−9 to 5.5 × 10−8 rad/s in the detection frequency band from 0.83~106.15 Hz and protect linear changes of sensitivity in the above bandpass. Some experimental results of an AFORS-1 application for a continuous monitoring of the rotational events in the Książ (Poland seismological observatory are also presented.

  14. Fibre optic system for monitoring rotational seismic phenomena.

    Science.gov (United States)

    Kurzych, Anna; Jaroszewicz, Leszek R; Krajewski, Zbigniew; Teisseyre, Krzysztof P; Kowalski, Jerzy K

    2014-03-19

    We outline the development and the application in a field test of the Autonomous Fibre-Optic Rotational Seismograph (AFORS), which utilizes the Sagnac effect for a direct measurement of the seismic-origin rotations of the ground. The main advantage of AFORS is its complete insensitivity to linear motions, as well as a direct measurement of rotational components emitted during seismic events. The presented system contains a special autonomous signal processing unit which optimizes its operation for the measurement of rotation motions, whereas the applied telemetric system based on the Internet allows for an AFORS remote control. The laboratory investigation of such two devices indicated that they keep an accuracy of no less than 5.1 × 10(-9) to 5.5 × 10(-8) rad/s in the detection frequency band from 0.83~106.15 Hz and protect linear changes of sensitivity in the above bandpass. Some experimental results of an AFORS-1 application for a continuous monitoring of the rotational events in the Książ (Poland) seismological observatory are also presented.

  15. Dynamic balancing of dual-rotor system with very little rotating speed difference

    Institute of Scientific and Technical Information of China (English)

    杨健; 贺世正; 王乐勤

    2003-01-01

    Unbalanced vibration in dual-rotor rotating machinery was studied with numerical simulations and experiments. A new method is proposed to separate vibration signals of inner and outer rotors for a system with very little difference in rotating speeds. Magnitudes and phase values of unbalance defects can be obtained directly by sampling the vibration signal synchronized with reference signal. The balancing process is completed by the reciprocity influence coefficients of inner and outer rotors method. Results showed the advantage of such method for a dual-rotor system as compared with conventional balancing.

  16. FOSREM - Fibre-Optic System for Rotational Events&Phenomena Monitoring

    Science.gov (United States)

    Jaroszewicz, Leszek; Krajewski, Zbigniew; Kurzych, Anna; Kowalski, Jerzy; Teisseyre, Krzysztof

    2016-04-01

    We present the construction and tests of fiber-optic rotational seismometer named FOSREM (Fibre-Optic System for Rotational Events&Phenomena Monitoring). This presented device is designed for detection and monitoring the one-axis rotational motions, brought about to ground or human-made structures both by seismic events and the creep processes. The presented system works by measuring Sagnac effect and generally consists of two basic elements: optical sensor and electronic part. The optical sensor is based on so-called the minimum configuration of FOG (Fibre-Optic Gyroscope) where the Sagnac effect produces a phase shift between two counter-propagating light beams proportional to the measured rotation speed. The main advantage of the sensor of this type is its complete insensitivity to linear motions and a direct measurement of rotational speed. It may work even when tilted, moreover, used in continuous mode it may record the tilt. The electronic system, involving specific electronic solutions, calculates and records rotational events data by realizing synchronous in a digital form by using 32 bit DSP (Digital Signal Processing). Storage data and system control are realised over the internet by using connection between FOSREM and GSM/GPS. The most significant attribute of our system is possibility to measure rotation in wide range both amplitude up to 10 rad/s and frequency up to 328.12 Hz. Application of the wideband, low coherence and high power superluminescent diode with long fibre loop and suitable low losses optical elements assures the theoretical sensitivity of the system equal to 2·10-8 rad/s/Sqrt(Hz). Moreover, the FOSREM is fully remote controlled as well as is suited for continuous, autonomous work in very long period of time (weeks, months, even years), so it is useful for systematic seismological investigation at any place. Possible applications of this system include seismic monitoring in observatories, buildings, mines and even on glaciers and in

  17. Wind Turbine Generator Modeling and Simulation Where Rotational Speed is the Controlled Variable

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Blaabjerg, Frede; Boldea, Ion

    2004-01-01

    the interaction between a wind turbine and the power system. The model is intended to simulate the behaviour of the wind turbine using induction generators both during normal operation. Sample simulation results for two induction generators (2/0.5 MW) validate the fundamental issues....... for application in variable speed wind turbines. The usual strategy is to control the power or the torque acting on the wind turbine shafts. This paper presents an alternative control strategy, where the rotational speed is the controlled variable. The paper describes a model, which is being developed to simulate...

  18. FEA ANALYSIS OF FRICTIONAL HEATING PROCESS (MAX. TEMPERATURE VS. ROTATIONAL SPEED)

    OpenAIRE

    Mr. Sachchidanand J Nimankar *, Prof. Sachin K. Dahake

    2016-01-01

    Friction stir welding process is a promising welding technology from its existence as it is easy to use, low energy costs, being ecology friendly process and with no requirement of any type of filler material. This study of FSW gives analysis of the maximum temperature generated during operation. This is done by making three dimensional non-linear model. This model helps in trend for the relationship between translational velocity of tool, rotation speed of the tool, and the maximum temperatu...

  19. Implementing Speed and Separation Monitoring in Collaborative Robot Workcells.

    Science.gov (United States)

    Marvel, Jeremy A; Norcross, Rick

    2017-04-01

    We provide an overview and guidance for the Speed and Separation Monitoring methodology as presented in the International Organization of Standardization's technical specification 15066 on collaborative robot safety. Such functionality is provided by external, intelligent observer systems integrated into a robotic workcell. The SSM minimum protective distance function equation is discussed in detail, with consideration for the input values, implementation specifications, and performance expectations. We provide analytical analyses and test results of the current equation, discuss considerations for implementing SSM in human-occupied environments, and provide directions for technological advancements toward standardization.

  20. Estimation of Rotational Velocity of Baseball Using High-Speed Camera Movies

    Science.gov (United States)

    Inoue, Takuya; Uematsu, Yuko; Saito, Hideo

    Movies can be used to analyze a player's performance and improve his/her skills. In the case of baseball, the pitching is recorded by using a high-speed camera, and the recorded images are used to improve the pitching skills of the players. In this paper, we present a method for estimating of the rotational velocity of a baseball on the basis of movies recorded by high-speed cameras. Unlike in the previous methods, we consider the original seam pattern of the ball seen in the input movie and identify the corresponding image from a database of images by adopting the parametric eigenspace method. These database images are CG Images. The ball's posture can be determined on the basis of the rotational parameters. In the proposed method, the symmetric property of the ball is also taken into consideration, and the time continuity is used to determine the ball's posture. In the experiments, we use the proposed method to estimate the rotational velocity of a baseball on the basis of real movies and movies consisting of CG images of the baseball. The results of both the experiments prove that our method can be used to estimate the ball's rotation accurately.

  1. Effect of rotational speed modulation on heat transport in a fluid layer with temperature dependent viscosity and internal heat source

    Directory of Open Access Journals (Sweden)

    B.S. Bhadauria

    2014-12-01

    Full Text Available In this paper, a theoretical investigation has been carried out to study the combined effect of rotation speed modulation and internal heating on thermal instability in a temperature dependent viscous horizontal fluid layer. Rayleigh–Bénard momentum equation with Coriolis term has been considered to describe the convective flow. The system is rotating about it is own axis with non-uniform rotational speed. In particular, a time-periodic and sinusoidally varying rotational speed has been considered. A weak nonlinear stability analysis is performed to find the effect of modulation on heat transport. Nusselt number is obtained in terms of amplitude of convection and internal Rayleigh number, and depicted graphically for showing the effects of various parameters of the system. The effect of modulated rotation speed is found to have a stabilizing effect for different values of modulation frequency. Further, internal heating and thermo-rheological parameters are found to destabilize the system.

  2. Study on the influence of the rotational speed of polishing disk on material removal in aspheric surface compliant polishing

    Directory of Open Access Journals (Sweden)

    Liyong Hu

    2015-03-01

    Full Text Available When a soft polishing tool is compressed on a stiff workpiece of curved surface, the contact area is a piece of the curved surface. In the process of aspheric surface polishing, the machining speed is always provided by the rotational speed of the spindle of a computer numerical control lathe. Yet, the polishing tool is usually made rotating to remove cutting scraps and broken abrasives from the contact area. The rotational speed of the polishing tool would change the distribution state of the relative speed in the whole contact area, and it would definitely change the volume of material removal in the surface of the workpiece. This article studies how the rotational speed of the polishing tool changes the distribution state of the relative speed in the whole contact area and material removal in the volume of the surface of the workpiece. The computing results show that the volume of material removal increases with the increase in both the rotational speed of polishing disk and the rotational speed of lathe spindle, but the polishing quality is totally not in this case.

  3. Earth Rotation Monitoring, UT1 Determinaiton and Prediction

    Science.gov (United States)

    2011-07-20

    article. 2011 Metrologia 48 S165 (http://iopscience.iop.org/0026-1394/48/4/S06) Download details: IP Address: 138.162.8.57 The article was downloaded...unlimited 13. SUPPLEMENTARY NOTES Metrologia 48 (2011) S165?S170 14. ABSTRACT Monitoring the Earth?s rotation angle is essential in various domains...ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 IOP PUBLISHING METROLOGIA Metrologia 48

  4. Health Monitoring of a Rotating Disk Using a Combined Analytical-Experimental Approach

    Science.gov (United States)

    Abdul-Aziz, Ali; Woike, Mark R.; Lekki, John D.; Baaklini, George Y.

    2009-01-01

    Rotating disks undergo rigorous mechanical loading conditions that make them subject to a variety of failure mechanisms leading to structural deformities and cracking. During operation, periodic loading fluctuations and other related factors cause fractures and hidden internal cracks that can only be detected via noninvasive types of health monitoring and/or nondestructive evaluation. These evaluations go further to inspect material discontinuities and other irregularities that have grown to become critical defects that can lead to failure. Hence, the objectives of this work is to conduct a collective analytical and experimental study to present a well-rounded structural assessment of a rotating disk by means of a health monitoring approach and to appraise the capabilities of an in-house rotor spin system. The analyses utilized the finite element method to analyze the disk with and without an induced crack at different loading levels, such as rotational speeds starting at 3000 up to 10 000 rpm. A parallel experiment was conducted to spin the disk at the desired speeds in an attempt to correlate the experimental findings with the analytical results. The testing involved conducting spin experiments which, covered the rotor in both damaged and undamaged (i.e., notched and unnotched) states. Damaged disks had artificially induced through-thickness flaws represented in the web region ranging from 2.54 to 5.08 cm (1 to 2 in.) in length. This study aims to identify defects that are greater than 1.27 cm (0.5 in.), applying available means of structural health monitoring and nondestructive evaluation, and documenting failure mechanisms experienced by the rotor system under typical turbine engine operating conditions.

  5. Effects of age and pathology on shear wave speed of the human rotator cuff.

    Science.gov (United States)

    Baumer, Timothy G; Dischler, Jack; Davis, Leah; Labyed, Yassin; Siegal, Daniel S; van Holsbeeck, Marnix; Moutzouros, Vasilios; Bey, Michael J

    2017-06-28

    Rotator cuff tears are common and often repaired surgically, but post-operative repair tissue healing, and shoulder function can be unpredictable. Tear chronicity is believed to influence clinical outcomes, but conventional clinical approaches for assessing tear chronicity are subjective. Shear wave elastography (SWE) is a promising technique for assessing soft tissue via estimates of shear wave speed (SWS), but this technique has not been used extensively on the rotator cuff. Specifically, the effects of age and pathology on rotator cuff SWS are not well known. The objectives of this study were to assess the association between SWS and age in healthy, asymptomatic subjects, and to compare measures of SWS between patients with a rotator cuff tear and healthy, asymptomatic subjects. SWE images of the supraspinatus muscle and intramuscular tendon were acquired from 19 asymptomatic subjects and 11 patients with a rotator cuff tear. Images were acquired with the supraspinatus under passive and active (i.e., minimal activation) conditions. Mean SWS was positively associated with age in the supraspinatus muscle and tendon under passive and active conditions (p ≤ 0.049). Compared to asymptomatic subjects, patients had a lower mean SWS in their muscle and tendon under active conditions (p ≤ 0.024), but no differences were detected under passive conditions (p ≥ 0.783). These findings identify the influences of age and pathology on SWS in the rotator cuff. These preliminary findings are an important step toward evaluating the clinical utility of SWE for assessing rotator cuff pathology. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  6. A Rotating Speed Controller Design Method for Power Levelling by Means of Inertia Energy in Wind Power Systems

    DEFF Research Database (Denmark)

    Qin, Zian; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    Power fluctuation caused by wind speed variations may be harmful for the stability of the power system as well as the reliability of the wind power converter, since it may induce thermal excursions in the solder joints of the power modules. Using the wind turbine rotor inertia energy for power...... leveling has been studied before, but no quantified analysis or generic design method have been found. In this paper, the transfer functions from the wind speed to electrical power, electromagnetic torque, and rotating speed are built based on which the rotating speed controller is designed...

  7. A computer-vision-based rotating speed estimation method for motor bearing fault diagnosis

    Science.gov (United States)

    Wang, Xiaoxian; Guo, Jie; Lu, Siliang; Shen, Changqing; He, Qingbo

    2017-06-01

    Diagnosis of motor bearing faults under variable speed is a problem. In this study, a new computer-vision-based order tracking method is proposed to address this problem. First, a video recorded by a high-speed camera is analyzed with the speeded-up robust feature extraction and matching algorithm to obtain the instantaneous rotating speed (IRS) of the motor. Subsequently, an audio signal recorded by a microphone is equi-angle resampled for order tracking in accordance with the IRS curve, through which the frequency-domain signal is transferred to an angular-domain one. The envelope order spectrum is then calculated to determine the fault characteristic order, and finally the bearing fault pattern is determined. The effectiveness and robustness of the proposed method are verified with two brushless direct-current motor test rigs, in which two defective bearings and a healthy bearing are tested separately. This study provides a new noninvasive measurement approach that simultaneously avoids the installation of a tachometer and overcomes the disadvantages of tacholess order tracking methods for motor bearing fault diagnosis under variable speed.

  8. Experimental study to the influences of rotational speed and blade shape on water vortex turbine performance

    Science.gov (United States)

    Kueh, T. C.; Beh, S. L.; Ooi, Y. S.; Rilling, D. G.

    2017-04-01

    Water vortex turbine utilizes the natural behaviour of water to form free surface vortex for energy extraction. This allows simple construction and ease of management on the whole water vortex power plant system. To our findings, the literature study specifically on water vortex turbine is inadequate and low efficiency was reported. Influences of operating speed and blade shape on turbine performance are the two parameters investigated in this study. Euler Turbomachinery Equation and velocity triangle are used in the improvement analysis. Two turbines with flat blades and curved blades are tested and compared. Both turbines show similar rotational speed at no load condition. This suggested that the circulation force of the water vortex has more dominant effect on the turbine rotational speed, compared to the turbine’s geometry. Flat-blades turbine showed maximum efficiency of 21.63% at 3.27 rad/s whereas curved-blades turbine showed 22.24% at 3.56 rad/s. When operating load is applied, the backward-leaning curve helps the turbine blades to reduce the disturbance on the water vortex, and hence provide a better performance.

  9. Ultrahigh-speed rotating nanoelectromechanical system devices assembled from nanoscale building blocks

    Science.gov (United States)

    Kim, Kwanoh; Xu, Xiaobin; Guo, Jianhe; Fan, D. L.

    2014-04-01

    The development of rotary nanomotors is crucial for advancing nanoelectromechanical system technology. In this work, we report design, assembly and rotation of ordered arrays of nanomotors. The nanomotors are bottom-up assembled from nanoscale building blocks with nanowires as rotors, patterned nanomagnets as bearings and quadrupole microelectrodes as stators. Arrays of nanomotors rotate with controlled angle, speed (over 18,000 r.p.m.), and chirality by electric fields. Using analytical modelling, we reveal the fundamental nanoscale electrical, mechanical and magnetic interactions in the nanomotor system, which excellently agrees with experimental results and provides critical understanding for designing metallic nanoelectromechanical systems. The nanomotors can be continuously rotated for 15 h over 240,000 cycles. They are applied for controlled biochemical release and demonstrate releasing rate of biochemicals on nanoparticles that can be precisely tuned by mechanical rotations. The innovations reported in this research, from concept, design and actuation to application, are relevant to nanoelectromechanical system, nanomedicine, microfluidics and lab-on-a-chip architectures.

  10. Magnetic field variation caused by rotational speed change in a magnetohydrodynamic dynamo.

    Science.gov (United States)

    Miyagoshi, Takehiro; Hamano, Yozo

    2013-09-20

    We have performed numerical magnetohydrodynamic dynamo simulations in a spherical shell with rotational speed or length-of-day (LOD) variation, which is motivated by correlations between geomagnetic field and climatic variations with ice and non-ice ages. The results show that LOD variation leads to magnetic field variation whose amplitude is considerably larger than that of LOD variation. The heat flux at the outer sphere and the zonal flow also change. The mechanism of the magnetic field variation due to LOD variation is also found. The keys are changes of dynamo activity and Joule heating.

  11. The monitoring of transient regimes on machine tools based on speed, acceleration and active electric power absorbed by motors

    Science.gov (United States)

    Horodinca, M.

    2016-08-01

    This paper intend to propose some new results related with computer aided monitoring of transient regimes on machine-tools based on the evolution of active electrical power absorbed by the electric motor used to drive the main kinematic chains and the evolution of rotational speed and acceleration of the main shaft. The active power is calculated in numerical format using the evolution of instantaneous voltage and current delivered by electrical power system to the electric motor. The rotational speed and acceleration of the main shaft are calculated based on the signal delivered by a sensor. Three real-time analogic signals are acquired with a very simple computer assisted setup which contains a voltage transformer, a current transformer, an AC generator as rotational speed sensor, a data acquisition system and a personal computer. The data processing and analysis was done using Matlab software. Some different transient regimes were investigated; several important conclusions related with the advantages of this monitoring technique were formulated. Many others features of the experimental setup are also available: to supervise the mechanical loading of machine-tools during cutting processes or for diagnosis of machine-tools condition by active electrical power signal analysis in frequency domain.

  12. Influence of rotational speed of centrifugal casting process on appearance, microstructure, and sliding wear behaviour of Al-2Si cast alloy

    Science.gov (United States)

    Mukunda, P. G.; Shailesh, Rao A.; Rao, Shrikantha S.

    2010-02-01

    Although the manner in which the molten metal flows plays a major role in the formation of the uniform cylinder in centrifugal casting, not much information is available on this topic. The flow in the molten metal differs at various rotational speeds, which in turn affects the final casting. In this paper, the influence of the flow of molten metal of hyper eutectic Al-2Si alloys at various rotational speeds is discussed. At an optimum speed of 800 rpm, a uniform cylinder was formed. For the rotational speeds below and above these speeds, an irregular shaped casting was formed, which is mainly due to the influence of melt. Primary á-Al particles were formed in the tube periphery at low rotational speed, and their sizes and shapes were altered with changes in rotational speeds. The wear test for the inner surface of the casting showed better wear properties for the casting prepared at the optimum speed of rotation.

  13. Envelope analysis of rotating machine vibrations in variable speed conditions: A comprehensive treatment

    Science.gov (United States)

    Abboud, D.; Antoni, J.; Sieg-Zieba, S.; Eltabach, M.

    2017-02-01

    Nowadays, the vibration analysis of rotating machine signals is a well-established methodology, rooted on powerful tools offered, in particular, by the theory of cyclostationary (CS) processes. Among them, the squared envelope spectrum (SES) is probably the most popular to detect random CS components which are typical symptoms, for instance, of rolling element bearing faults. Recent researches are shifted towards the extension of existing CS tools - originally devised in constant speed conditions - to the case of variable speed conditions. Many of these works combine the SES with computed order tracking after some preprocessing steps. The principal object of this paper is to organize these dispersed researches into a structured comprehensive framework. Three original features are furnished. First, a model of rotating machine signals is introduced which sheds light on the various components to be expected in the SES. Second, a critical comparison is made of three sophisticated methods, namely, the improved synchronous average, the cepstrum prewhitening, and the generalized synchronous average, used for suppressing the deterministic part. Also, a general envelope enhancement methodology which combines the latter two techniques with a time-domain filtering operation is revisited. All theoretical findings are experimentally validated on simulated and real-world vibration signals.

  14. Contributions of joint rotations to ball release speed during cricket bowling: a three-dimensional kinematic analysis.

    Science.gov (United States)

    Zhang, Yanxin; Unka, Jayesh; Liu, Guangyu

    2011-09-01

    The purpose of this study was to discover the contributions of individual upper body segmental rotations to ball release speed for cricket bowling and determine whether attempting to forcefully flex the lower trunk leads to an increase in ball release speed and bowling accuracy. Three dimensional kinematic data of eight male fast bowlers were recorded by a Vicon motion capture system under three cricket bowling conditions: (1) participants bowled at their stock delivery speeds (sub-max condition), (2) participants bowled at their absolute maximal speeds (max condition), and (3) participants bowled at their absolute maximal speeds but forced to flex the lower trunk (max-trunk condition). The accuracy of each delivery was also measured. The results showed that the average ball release speeds for the max-trunk condition were faster than the other two conditions. A general pattern of proximal to distal sequencing was observed for all three conditions. There was a slight decrement in accuracy seen in the max-trunk condition with respect to the other two conditions. For all three conditions, the upper arm rotation made the largest contribution, followed in turn by torso and thorax rotation, pelvis rotation, linear velocity of pelvis, and forearm and hand rotation.

  15. Characterization of the tensile properties of friction stir welded aluminum alloy joints based on axial force, traverse speed, and rotational speed

    Science.gov (United States)

    Panda, Biranchi; Garg, A.; Jian, Zhang; Heidarzadeh, Akbar; Gao, Liang

    2016-09-01

    Friction stir welding (FSW) process has gained attention in recent years because of its advantages over the conventional fusion welding process. These advantages include the absence of heat formation in the affected zone and the absence of large distortion, porosity, oxidation, and cracking. Experimental investigations are necessary to understand the physical behavior that causes the high tensile strength of welded joints of different metals and alloys. Existing literature indicates that tensile properties exhibit strong dependence on the rotational speed, traverse speed, and axial force of the tool that was used. Therefore, this study introduces the experimental procedure for measuring tensile properties, namely, ultimate tensile strength (UTS) and tensile elongation of the welded AA 7020 Al alloy. Experimental findings suggest that a welded part with high UTS can be achieved at a lower heat input compared with the high heat input condition. A numerical approach based on genetic programming is employed to produce the functional relationships between tensile properties and the three inputs (rotational speed, traverse speed, and axial force) of the FSW process. The formulated models were validated based on the experimental data, using the statistical metrics. The effect of the three inputs on the tensile properties was investigated using 2D and 3D analyses. A high UTS was achieved, including a rotational speed of 1050 r/min and traverse speed of 95 mm/min. The results also indicate that 8 kN axial force should be set prior to the FSW process.

  16. Elastic dynamic research of high speed multi-link precision press considering structural stiffness of rotation joints

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Feng Feng; Sun, Yu; Peng, Bin Bin [School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing (China)

    2016-10-15

    An elastic dynamic model of high-speed multi-link precision press considering structural stiffness of rotation joints was established by the finite element method. In the finite element model, rotation joint was established by four bar elements with equivalent stiffness, and connected link was established by beam element. Then, the elastic dynamics equation of the system was established, and modal superposition method was used to solve the dynamic response. Compared with the traditional elastic dynamic model with perfect constraint of the rotation joints, the elastic dynamic response value of the improved model is larger. To validate the presented new method of elastic dynamics analysis with stiffness of rotation joints, a related test of slider Bottom dead center (BDC) position in different speed was designed. The test shows that the model with stiffness of rotation joints is more reasonable. So it provides a reasonable theory and method for dynamic characteristics research of such a multi-link machine.

  17. Shoulder Rotator Muscle Dynamometry Characteristics: Side Asymmetry and Correlations with Ball-Throwing Speed in Adolescent Handball Players

    Directory of Open Access Journals (Sweden)

    Pontaga Inese

    2014-10-01

    Full Text Available The aim of the investigation was to: 1 compare shoulder external/internal rotator muscles’ peak torques and average power values and their ratios in the dominant and non-dominant arm; 2 determine correlations between shoulder rotator muscles’ peak torques, average power and ball-throwing speed in handball players. Fourteen 14 to 15- year-old male athletes with injury-free shoulders participated in the study (body height: 176 ± 7 cm, body mass 63 ± 9 kg. The tests were carried out by an isokinetic dynamometer system in the shoulder internal and external rotation movements at angular velocities of 60°/s, 90°/s and 240°/s during concentric contractions. The eccentric external- concentric internal rotator muscle contractions were performed at the velocity of 90°/s. The player threw a ball at maximal speed keeping both feet on the floor. The speed was recorded with reflected light rays. Training in handball does not cause significant side asymmetry in shoulder external/internal rotator muscle peak torques or the average power ratio. Positive correlations between isokinetic characteristics of the shoulder internal and external rotator muscles and ball-throwing speed were determined. The power produced by internal rotator muscles during concentric contractions after eccentric contractions of external rotator muscles was significantly greater in the dominant than in the non-dominant arm. Thus, it may be concluded that the shoulder eccentric external/concentric internal rotator muscle power ratio is significantly greater than this ratio in the concentric contractions of these muscles

  18. Shoulder Rotator Muscle Dynamometry Characteristics: Side Asymmetry and Correlations with Ball-Throwing Speed in Adolescent Handball Players

    Science.gov (United States)

    Pontaga, Inese; Zidens, Janis

    2014-01-01

    The aim of the investigation was to: 1) compare shoulder external/internal rotator muscles’ peak torques and average power values and their ratios in the dominant and non-dominant arm; 2) determine correlations between shoulder rotator muscles’ peak torques, average power and ball-throwing speed in handball players. Fourteen 14 to 15-year-old male athletes with injury-free shoulders participated in the study (body height: 176 ± 7 cm, body mass 63 ± 9 kg). The tests were carried out by an isokinetic dynamometer system in the shoulder internal and external rotation movements at angular velocities of 60°/s, 90°/s and 240°/s during concentric contractions. The eccentric external– concentric internal rotator muscle contractions were performed at the velocity of 90°/s. The player threw a ball at maximal speed keeping both feet on the floor. The speed was recorded with reflected light rays. Training in handball does not cause significant side asymmetry in shoulder external/internal rotator muscle peak torques or the average power ratio. Positive correlations between isokinetic characteristics of the shoulder internal and external rotator muscles and ball-throwing speed were determined. The power produced by internal rotator muscles during concentric contractions after eccentric contractions of external rotator muscles was significantly greater in the dominant than in the non-dominant arm. Thus, it may be concluded that the shoulder eccentric external/concentric internal rotator muscle power ratio is significantly greater than this ratio in the concentric contractions of these muscles. PMID:25414738

  19. The influence of Earth rotation in neutrino speed measurements between CERN and the OPERA detector

    CERN Document Server

    Kuhn, Markus G

    2011-01-01

    The OPERA neutrino experiment at the underground Gran Sasso Laboratory recently reported, in arXiv:1109.4897v1, high-accuracy velocity measurements of neutrinos from the CERN CNGS beam over the 730 km distance between the two laboratories. This raised significant interest, as the observed neutrinos appeared to arrive at the OPERA detector about 60 ns (or equivalently 18 m) earlier than would have been expected if they had traveled at the speed of light, with high statistical significance. As the authors did not indicate whether and how they took into account the Coriolis effect that Earth's rotation has on the (southeastwards traveling) neutrinos, this brief note quantifies this effect. It would explain only a 2.2 ns earlier arrival time.

  20. Minimum rotation speed to prevent coning phenomena in compendium paddle dissolution apparatus.

    Science.gov (United States)

    Higuchi, Mizuki; Yoshihashi, Yasuo; Tarada, Katsuhide; Sugano, Kiyohiko

    2014-12-18

    The purpose of the present study was to investigate the applicability of the Zwietering equation to coning phenomena which often occur during dissolution testing. The minimum rotation speed at which coning phenomena disappeared (no coning rpm, NCrpm) was experimentally determined for various particle and fluid properties in a compendium paddle apparatus with a round-bottom unbaffled vessel. The particle size, relative density and kinematic viscosity exponents in the Zwietering equation were optimized for NCrpm. The particle size and relative density exponents were found to be similar with those for the general tank configurations of cylindrical flat-bottom baffled vessels. However, the kinematic viscosity exponent was significantly different. The equation obtained in this study showed sufficient accuracy (r(2)=0.98, average error=12rpm) to estimate the occurrence of coning. The Zwietering equation was found to be applicable to the coning phenomena in the compendium paddle apparatus.

  1. Barium Strontium Titanate Thin Film Growth with rotational speed variation as a satellite temperature sensor prototype

    Science.gov (United States)

    Mulyadi; Rika, W.; Sulidah; Irzaman; Hardhienata, Hendradi

    2017-01-01

    Barium Strontium Titanate(BST) is a promising material for sensor devices such as temperature and infrared sensor. BaxSr1-xTiO3 thin films with affordable Si substrate were prepared by chemical solution deposition method and spin coating technique for 30 seconds with variation in rotation speed (3000 rpm, 5500 rpm and 8000 rpm). A high baking temperature at 8500C has been used for 15 hours during the annealing process. The thickness of BST film was calculated via gravimetric calculation. USB 2000 VIS-NIR was used to characterize the optical properties of BST thin film. The obtained reflectance curve showed that the most reflected wavelengths were in the range of 408-452 nm respectively. The result of the optical film characterization is very important for further development as a sensor in satellite technology.

  2. Using High Speed Rotating Gas to Study Angular Momentum in Accretion Disks

    Science.gov (United States)

    Berrios, William; Greess, Samuel; Merino, Enrique; Ji, Hantao

    2013-10-01

    Accretion disks are a sheet of gas and dust which surrounds black holes and quasars. The angular momentum in accretion disks is one of the biggest mysteries in astrophysics. A machine was recently built to create accretion disks in a closed chamber. In order to study this, there are several important instruments that are used: a fog machine to see the accretion disks form within the chamber, a high speed camera to observe and record the formation of the accretion disks, and Particle Image Velocimetry (PIV) to analyze velocity profile of the rotating gas and better understand this phenomenon. By collecting relevant data and subsequent computational analysis, results from a previous experiment are reproduced, expanded and the new properties observed with this experiment are characterized. A discussion of any modifications done to the machine, technical challenges and preliminary results will be presented.

  3. Experimental Motion Analysis of Radially Rotating Beams Using High-Speed Camera and Motion Analyzer

    Directory of Open Access Journals (Sweden)

    K.H. Low

    1996-01-01

    Full Text Available Although strain gauges can be attached to a system for vibration analysis, wires connected to the strain gauges may disturb the system and affect the accuracy of the strain measurement. As an alternative, this work presents the use of a high-speed camera combined with a motion analyzer to study the motion of rotating flexible beams. One end of the beam is rigidly connected to a motor, while the other end is free. White stickers placed on selected points on a given beam are the reference points in a digitization process. The modes of the vibrating beams can be filmed and analyzed. The vibration parameters, such as deflection and frequency, can be obtained by using a film motion analyzer. The results show that the beam does not behave in a clamped-free or a pinned-free fashion, but instead occurs at an intermediate boundary between these two classical conditions.

  4. Effect of Rotational Speed on Microstructure and Mechanical Properties of Refill Friction Stir Spot Welded 2024 Al Alloy

    Science.gov (United States)

    Li, Zhengwei; Gao, Shuangsheng; Ji, Shude; Yue, Yumei; Chai, Peng

    2016-04-01

    Refill friction stir spot welding (RFSSW) was successfully used to weld alclad 2024 aluminum alloy with different thicknesses. Effects of tool rotational speed on the weld formation, microstructure, and mechanical properties of the RFSSW welds were mainly discussed. Results show that keyhole is successfully refilled and welding defects such as flash, annular groove, and material adhesion can be observed. A bright contrast bonding ligament is found embedded in the weld and it is thicker in the center. Defects of hook, void, lack of mixing, and incomplete refilling can be found at the thermo-mechanically affected zone/stir zone (TMAZ/SZ) interface, which can be attributed to weak metallurgical bonding effect. With increasing the tool rotational speed, thickness of the bonding ligament decreases, grains in the SZ coarsen, hardness of the SZ decreases, and lap shear load of the welds decreases. When changing the rotating speed, impact strength shows rather complicated variation trend.

  5. LIDAR wind speed measurements from a rotating spinner (SpinnerEx 2009)

    Energy Technology Data Exchange (ETDEWEB)

    Angelou, N.; Mikkelsen, Torben; Hansen, Kasper H.; Sjoeholm, M.; Harris, M.

    2010-08-15

    In the context of the increasing application of remote sensing techniques in wind energy, the feasibility of upwind observations via a spinner-mounted wind lidar was tested during the SpinnerEx 2009 experiment. The objective was to install a QinetiQ (Natural Power) ZephIR lidar in the rotating spinner of a MW-sized wind turbine, and investigate the approaching wind fields from this vantage point. Time series of wind speed measurements from the lidar with 50 Hz sampling rate were successfully obtained for approximately 60 days, during the measurement campaign lasting from April to August 2009. In this report, information is given regarding the experimental setup and the lidar's operation parameters. The geometrical model used for the reconstruction of the scanning pattern of the lidar is described. This model takes into account the lidar's pointing direction, the spinner axis's vertical tilt and the wind turbine's yaw relative to the mean wind speed direction. The data analysis processes are documented. A methodology for the calculation of the yaw misalignment of the wind turbine relative to the wind direction, as a function of various averaging times, is proposed, using the lidar's instantaneous line-of-sight radial wind speed measurements. Two different setups have been investigated in which the approaching wind field was measured at distances of 0.58 OE and 1.24 OE rotor diameters upwind, respectively. For both setups, the instantaneous yaw misalignment of the turbine has been estimated from the lidar measurements. Data from an adjacent meteorological mast as well as data logged within the wind turbine's control system were used to evaluate the results. (author)

  6. Uncertainty Reduced Novelty Detection Approach Applied to Rotating Machinery for Condition Monitoring

    Directory of Open Access Journals (Sweden)

    S. Ma

    2015-01-01

    Full Text Available Novelty detection has been developed into a state-of-the-art technique to detect abnormal behavior and trigger alarm for in-field machine maintenance. With built-up models of normality, it has been widely applied to several situations with normal supervising dataset such as shaft rotating speed and component temperature available meanwhile in the absence of fault information. However, the research about vibration transmission based novelty detection remains unnoticed until recently. In this paper, vibration transmission measurement on rotor is performed; based on extreme value distributions, thresholds for novelty detection are calculated. In order to further decrease the false alarm rate, both measurement and segmentation uncertainty are considered, as they may affect threshold value and detection correctness heavily. Feasible reduction strategies are proposed and discussed. It is found that the associated multifractal coefficient and Kullback-Leibler Divergence operate well in the uncertainty reduction process. As shown by in situ applications to abnormal rotor with pedestal looseness, it is demonstrated that the abnormal states are detected. The higher specificity value proves the effectiveness of proposed uncertainty reduction method. This paper shows novel achievements of uncertainty reduced novelty detection applied to vibration signal in dynamical system and also sheds lights on its utilization in the field of health monitoring of rotating machinery.

  7. Effect of tool rotational speed and penetration depth on dissimilar aluminum alloys friction stir spot welds

    Directory of Open Access Journals (Sweden)

    Joaquín M. Piccini

    2017-03-01

    Full Text Available In the last years, the automotive industry is looking for the use of aluminum parts in replace of steel parts in order to reduce the vehicles weight. These parts have to be joined, for instance, by welding processes. The more common welding process in the automotive industry is the Resistance Spot Welding (RSW technique. However, RSW of aluminum alloys has many disadvantages. Regarding this situation, a variant of the Friction Stir Welding process called Friction Stir Spot Welding (FSSW has been developed, showing a strong impact in welding of aluminum alloys and dissimilar materials in thin sheets. Process parameters affect the characteristics of the welded joints. However, the information available on this topic is scarce, particularly for dissimilar joints and thin sheets. The aim of this work was to study the effect of the rotational speed and the tool penetration depth on the characteristics of dissimilar FSS welded joints. Defects free joints have been achieved with higher mechanical properties than the ones reported. The maximum fracture load was 5800 N. It was observed that the effective joint length of the welded spots increased with the tool penetration depth, meanwhile the fracture load increased and then decreased. Finally, welding at 1200 RPM produced welded joints with lower mechanical properties than the ones achieved at 680 and 903 RPM.

  8. Dechlorination of pentachlorophenol by grinding at low rotation speed in short time

    Institute of Scientific and Technical Information of China (English)

    Zhi Xu; Xiaoyu Zhang; Qingzhi Fei

    2015-01-01

    In order to apply grinding method for degradation of pentachlorophenol (PCP) to an industrial scale, the propor-tion of different materials [CaO, SiO2 and CO(NH2)2] and the size of grinding balls were examined. For saving en-ergy and increasing dechlorination efficiency, the rotation speed and grinding time were maintained at relatively low values. At a mass ratio of grinding bal s to materials (40:1), PCP was added into a big steel jar (300 ml) with other materials to grind at 300 r·min−1 for 5 h. The results indicated that when PCP was mixed with CaO and SiO2 in a molar ratio of 1:60:60, the best dechlorination of 58.4%was achieved. CO(NH2)2 could not be used as hydro-gen donor in the dehalogenation by mechanochemical reaction, since it restrained the dechlorination process. The size of grinding balls has significant effect on the reaction. The experiment with 5 mm steel balls indicates that the weight is too light to provide appropriate energy for the reaction, while steel balls of 10 and 15 mm could give better dechlorination reaction. It indicates that dechlorination depends on the mass of balls and fill rate.

  9. High-speed measurement of axial grain transport in a rotating drum

    Science.gov (United States)

    van Bussel, Frank; Khan, Zeina; Schaber, Marc; Seemann, Ralf; Scheel, Mario; Dimichiel, Marco

    2012-02-01

    Over short timescales granular mixtures separate by size when tumbled in a partially filled horizontal drum. The smaller grains move toward the axis of rotation to form a central core; undulations in this core gradually increase in amplitude until they grow into axial bands. Using non-invasive high-speed synchrotron x-ray particle tracking, we investigate the axial transport properties of tracer particles traveling amongst glass spheres. This new technique allows us to gather data on time scales not previously possible. When the tracers are present in larger proportions the mixtures we used should have different tendencies to segregate axially according to size ratio; one of our findings, however, is that when the tracer concentration is low the single-particle dynamics of these mixtures do not depend on the relative particle sizes in any appreciable way. This implies that the potential for a mixture to axially segregate cannot be inferred from the microscopic dynamics of individual small particles. A second finding is that while the slope of the mean-squared displacement is close to that expected from diffusive transport, as determined from the single-particle dynamics, more detailed analyses indicate anomalous transport.

  10. Design optimization under uncertainty and speed variability for a piezoelectric energy harvester powering a tire pressure monitoring sensor

    Science.gov (United States)

    Toghi Eshghi, Amin; Lee, Soobum; Kazem Sadoughi, Mohammad; Hu, Chao; Kim, Young-Cheol; Seo, Jong-Ho

    2017-10-01

    Energy harvesting (EH) technologies to power small sized electronic devices are attracting great attention. Wasted energy in a vehicle’s rotating tire has a great potential to enable self-powered tire pressure monitoring sensors (TPMS). Piezoelectric type energy harvesters can be used to collect vibrational energy and power such systems. Due to the presence of harsh acceleration in a rotating tire, a design tradeoff needs to be studied to prolong the harvester’s fatigue life as well as to ensure sufficient power generation. However, the design by traditional deterministic design optimization (DDO) does not show reliable performance due to the lack of consideration of various uncertainty factors (e.g., manufacturing tolerances, material properties, and loading conditions). In this study, we address a new EH design formulation that considers the uncertainty in car speed, dimensional tolerances and material properties, and solve this design problem using reliability-based design optimization (RBDO). The RBDO problem is formulated to maximize compactness and minimize weight of a TPMS harvester while satisfying power and durability requirements. A transient analysis has been done to measure the time varying response of EH such as power generation, dynamic strain, and stress. A conservative design formulation is proposed to consider the expected power from varied speed and stress at higher speed. When compared to the DDO, the RBDO results show that the reliability of EH is increased significantly by scarifying the objective function. Finally, experimental test has been conducted to demonstrate the merits of RBDO design over DDO.

  11. The in-plane free vibration of an elastically supported thin ring rotating at high speeds revisited

    Science.gov (United States)

    Lu, T.; Tsouvalas, A.; Metrikine, A. V.

    2017-08-01

    The in-plane free vibration of a rotating thin ring is revisited in this paper. A new model is proposed which accounts for the elastic foundation and the through-thickness variation of the radial stress. The emphasis is placed on a proper consideration of the geometrical nonlinearity, which is essential for the consistent modelling of the ring stiffening resulting from the radial expansion caused by rotation. The in-plane stability of a thin ring rotating at relatively high speeds is analysed thoroughly. It is shown that the ring can become unstable should the rotational speed exceed a critical value. This result is new as in most known to the authors previous studies the stability problem is either not considered or it is stated that the in-plane vibration of a rotating ring is stable. In the studies which did address the instability, the conclusions and the employed models are prone to criticism. A parametric study is conducted to illustrate the effects of the ring properties on the in-plane stability. Finally, modes, which appear as stationary displacement patterns of the ring to an observer in the space-fixed reference system, are investigated. It is shown that the stationary patterns can occur prior to the onset of the instability for certain ring parameters.

  12. High-Speed Video-Oculography for Measuring Three-Dimensional Rotation Vectors of Eye Movements in Mice.

    Directory of Open Access Journals (Sweden)

    Takao Imai

    Full Text Available The mouse is the most commonly used animal model in biomedical research because of recent advances in molecular genetic techniques. Studies related to eye movement in mice are common in fields such as ophthalmology relating to vision, neuro-otology relating to the vestibulo-ocular reflex (VOR, neurology relating to the cerebellum's role in movement, and psychology relating to attention. Recording eye movements in mice, however, is technically difficult.We developed a new algorithm for analyzing the three-dimensional (3D rotation vector of eye movement in mice using high-speed video-oculography (VOG. The algorithm made it possible to analyze the gain and phase of VOR using the eye's angular velocity around the axis of eye rotation.When mice were rotated at 0.5 Hz and 2.5 Hz around the earth's vertical axis with their heads in a 30° nose-down position, the vertical components of their left eye movements were in phase with the horizontal components. The VOR gain was 0.42 at 0.5 Hz and 0.74 at 2.5 Hz, and the phase lead of the eye movement against the turntable was 16.1° at 0.5 Hz and 4.88° at 2.5 Hz.To the best of our knowledge, this is the first report of this algorithm being used to calculate a 3D rotation vector of eye movement in mice using high-speed VOG. We developed a technique for analyzing the 3D rotation vector of eye movements in mice with a high-speed infrared CCD camera. We concluded that the technique is suitable for analyzing eye movements in mice. We also include a C++ source code that can calculate the 3D rotation vectors of the eye position from two-dimensional coordinates of the pupil and the iris freckle in the image to this article.

  13. Influence of loading and rotation speed on Friction and Wear properties of CuAlBi Alloy

    Institute of Scientific and Technical Information of China (English)

    Liu Rongchang; Dong Litao; Li Xingyuan; Chen Xiuhong

    2007-01-01

    The variation of the friction coefficient of the CuAlBi alloy at different connecting loading and friction speed were investigated by using MMU-5G sliding friction-wear tester, besides, the wear mass loss of the CuAlBi alloy was measured, and the influence of loading and rotation speed on friction and wear properties of CuAlBi alloy was also discussed. The results show that the friction coefficient increase then decrease with increase of connecting loading as well as decreases with increase of friction speed, and the wear loss mass increases with increase of connecting loading and friction speed. As a result, the wear failure form of CuAlBi alloy is mainly ploughing.

  14. Fast and Careless or Careful and Slow? Apparent Holistic Processing in Mental Rotation Is Explained by Speed-Accuracy Trade-Offs

    Science.gov (United States)

    Liesefeld, Heinrich René; Fu, Xiaolan; Zimmer, Hubert D.

    2015-01-01

    A major debate in the mental-rotation literature concerns the question of whether objects are represented holistically during rotation. Effects of object complexity on rotational speed are considered strong evidence against such holistic representations. In Experiment 1, such an effect of object complexity was markedly present. A closer look on…

  15. Real-Time Condition Monitoring and Fault Diagnosis of Gear Train Systems Using Instantaneous Angular Speed (IAS) Analysis

    Science.gov (United States)

    Sait, Abdulrahman S.

    This dissertation presents a reliable technique for monitoring the condition of rotating machinery by applying instantaneous angular speed (IAS) analysis. A new analysis of the effects of changes in the orientation of the line of action and the pressure angle of the resultant force acting on gear tooth profile of spur gear under different levels of tooth damage is utilized. The analysis and experimental work discussed in this dissertation provide a clear understating of the effects of damage on the IAS by analyzing the digital signals output of rotary incremental optical encoder. A comprehensive literature review of state of the knowledge in condition monitoring and fault diagnostics of rotating machinery, including gearbox system is presented. Progress and new developments over the past 30 years in failure detection techniques of rotating machinery including engines, bearings and gearboxes are thoroughly reviewed. This work is limited to the analysis of a gear train system with gear tooth surface faults utilizing angular motion analysis technique. Angular motion data were acquired using an incremental optical encoder. Results are compared to a vibration-based technique. The vibration data were acquired using an accelerometer. The signals were obtained and analyzed in the phase domains using signal averaging to determine the existence and position of faults on the gear train system. Forces between the mating teeth surfaces are analyzed and simulated to validate the influence of the presence of damage on the pressure angle and the IAS. National Instruments hardware is used and NI LabVIEW software code is developed for real-time, online condition monitoring systems and fault detection techniques. The sensitivity of optical encoders to gear fault detection techniques is experimentally investigated by applying IAS analysis under different gear damage levels and different operating conditions. A reliable methodology is developed for selecting appropriate testing

  16. Influence of rotational speed during centrifugal casting on sliding wear behaviour of the Al-2Si alloy

    Institute of Scientific and Technical Information of China (English)

    P. G. MUKUNDA; A. SHAILESH RAO; Shrikantha S. RAO

    2009-01-01

    The microstructures and dry sliding wearbehaviour of an Al-2Si alloy cast centrifugally are studied. Results indicate that at optimum speed the cast has a microstructure consisting of uniformly distributed α-Al grains and fine eutectic silicon grains. The cast exhibited better wear resistance compared to the same cast prepared at different rpms. This paper attempts to investigate the influence of the microstructural changes in the Al-2Si alloy by varying the rotational speed of the mould and its combined action on the dry sliding wear behaviour.

  17. Tactile shoe inlays for high speed pressure monitoring

    DEFF Research Database (Denmark)

    Drimus, Alin; Mátéfi-Tempfli, Stefan

    2015-01-01

    pressure sensitive cells and the use of high speed electronics and multiplexing algorithms provides frame rates of 100 Hz. The sensors tolerate overloads while showing a consistent output. The developed prototypes show a high potential not only for robotics, but also for use in sensorised human prosthetics.......This work describes the development of flexible tactile sensor shoe inlays for humanoid robots. Their design is based on a sandwich structure of flexible layers with a thin sheet of piezoresistive rubber as main transducer element. The layout and patterning of top and bottom electrodes give 1024...

  18. Sensor network architecture for intelligent high-speed train on-board monitoring

    Institute of Scientific and Technical Information of China (English)

    Xiao-fan WU; Chun CHEN; Jia-jun BU; Gang CHEN

    2011-01-01

    The China's high-speed railway is experiencing a rapid growth.Its operating mileage and the number of operating trains will exceed 45000 km and 1500 trains by 2015,respectively.During the long range and constant high-speed operation,the high-speed trains have extremely complex and varied work conditions.Such a situation creates a huge demand for high-speed train on-board monitoring.In this paper,architecture for high-speed train on-board monitoring sensor network is proposed.This architecture is designed to achieve the goals of reliable sensing,scalable data transporting,and easy management.The three design goals are realized separately.The reliable sensing is achieved by deploying redundant sensor nodes in the same components.Then a hierarchal transporting scheme is involved to meet the second goal.Finally,an electronic-tag based addressing method is introduced to solve the management problem.

  19. Continuous Earth Rotation Monitoring with the large Ring Laser G

    Science.gov (United States)

    Schreiber, K. U.; Klügel, T.; Wells, J. P.; Holdaway, J.; Gebauer, A.

    2010-12-01

    Over the last decade, ring lasers have found their way back into the research laboratories. By scaling them up in size, they have gained several orders of magnitude over their commercial counterparts, both in sensitivity and stability. Unlike the established space geodetic techniques SLR/LLR and VLBI, ring lasers can be operated autonomous and continuously. Furthermore laser gyros reach a resolution of 1 pico-rad/s already after an integration time of less than 2 hours. This opens the door for the research of high frequency variations in Earth rotation. Over the last year we have improved the sensor sensitivity by as much as a factor of 3 in order to reach the shot noise limit at 2.1x10-11 rad/s/sqrt(Hz). So the regime of ΔΩ/Ω ≈ 10-9 of Earth rotation becomes accessible to a local rotation sensor. Recent efforts concentrate on the reduction of scale factor instability by controlling the drift induced by atmospheric pressure variations and the corresponding temperature changes from adiabatic expansion and compression of the local air as well as a new approach to the modeling of the behavior of the sensor location. This talk outlines recent progress in Sagnac interferometry.

  20. The Role of Tip Leakage Flow in Triggering Rotating Stall of a Low Speed Compressor under Inlet Distortion

    Institute of Scientific and Technical Information of China (English)

    Jingxuan Zhang; Feng Lin; Jingyi Chen; Chaoqun Nie

    2009-01-01

    The stall behavior in a single-stage low-speed axial compressor under rotating inlet distortion (RID) is investi-gated in the first half of this paper. The tests demonstrate that the tip leakage flow (TLF) plays an important rolein triggering rotating stall. The tracking of the spike-like disturbances caused by the spillage of TLV indicates that most of such spike-like disturbances will be smeared by non-distorted sector and the growth of the spike-like dis-turbances actually relate closely to how and how often the path of the propagating disturbances come across the path of the rotating distorted sector. In the second half of this paper, micro air injections are applied to test the ef-fect behavior of TLF on stall inception. Contrasts to without micro air injections, the spike-like disturbances are much fewer, so the possibilities that spike-like disturbances may trigger rotating stall are fewer too. As a result, the compressor gets a lower mass flow rate at stall for both co-rotating inlet distortion and counter-rotating inlet distortion.

  1. Internal Flow of a High Specific-Speed Diagonal-Flow Fan (Rotor Outlet Flow Fields with Rotating Stall

    Directory of Open Access Journals (Sweden)

    Norimasa Shiomi

    2003-01-01

    Full Text Available We carried out investigations for the purpose of clarifying the rotor outlet flow fields with rotating stall cell in a diagonal-flow fan. The test fan was a high–specific-speed (ns=1620 type of diagonal-flow fan that had 6 rotor blades and 11 stator blades. It has been shown that the number of the stall cell is 1, and its propagating speed is approximately 80% of its rotor speed, although little has been known about the behavior of the stall cell because a flow field with a rotating stall cell is essentially unsteady. In order to capture the behavior of the stall cell at the rotor outlet flow fields, hot-wire surveys were performed using a single-slant hotwire probe. The data obtained by these surveys were processed by means of a double phase-locked averaging technique, which enabled us to capture the flow field with the rotating stall cell in the reference coordinate system fixed to the rotor. As a result, time-dependent ensemble averages of the three-dimensional velocity components at the rotor outlet flow fields were obtained. The behavior of the stall cell was shown for each velocity component, and the flow patterns on the meridional planes were illustrated.

  2. Influence of rotation speed on natural frequency: A short introduction and presentation of an imaginary 'antigravity' world

    CERN Document Server

    Provatidis, Christopher G

    2011-01-01

    We present an instructive way to introduce the subject of resonance using a typical spring-mass system without damping. In contrast to the standard approach found in most textbooks, here we propose a way to extend the lectures from common translational systems to rotating ones. In the latter case, particular attention is paid to the role of the variable centripetal force. The students will find analytical solutions of the simplest possible ordinary differential equations of motion and see that the natural frequency strongly depends on the rotation speed, the latter being a simple vector sum. The analysis reveals that always the resultant ground force is harmonic. In order to depict the significance in the influence of rotation on natural frequency, we present an imaginary 'antigravity' world in which the aforementioned dependency is absent.

  3. Research on Network-based Integrated Condition Monitoring Unit for Rotating Machinery

    Institute of Scientific and Technical Information of China (English)

    XI Xiao-peng; ZHANG Wen-rui; XI Shuan-min; JING Min-qing; YU Lie

    2004-01-01

    In this paper, a network-based monitoring unit for condition monitoring and fault diagnosis of rotating machinery is designed and implemented. With the technology of DSP( Digital signal processing), TCP/IP, and simultaneous acquisition, a mechanism of multi-process and inter-process communication, the integrating problem of signal acquisition, the data dynamic management and network-based configuration in the embedded condition monitoring system is solved. It offers the input function of monitoring information for network-based condition monitoring and a fault diagnosis system.

  4. The Long-Term Settlement Deformation Automatic Monitoring System for the Chinese High-Speed Railway

    Directory of Open Access Journals (Sweden)

    Xu Wang

    2015-01-01

    Full Text Available The Beijing-Shanghai high-speed railway is one of the milestones of China’s high-speed railway development and its security plays a significant role in China’s economic and social development. However, the evaluation methods used for large-scale security operations and important infrastructure systems, such as the high-speed railways, are discrete and nonlinear; thus they cannot issue emergency warnings in a timely manner. The emergence of optical fiber sensing technology can solve this problem. This technology has progressed rapidly in its application to the monitoring of railway security and it has attracted much attention within the industry. This study considers the newly built passenger railway line between Shijiazhuang and Jinan as an example. The web-based, all-in-one fiber Bragg grating static level is described as well as a set of online monitoring systems, which is automated, real-time, remote, visual, and adaptable to the standards of the Beijing-Shanghai high-speed railway. According to our theoretical analysis, the planned automated monitoring of settlement deformation for the Beijing-Shanghai high-speed railway and the real-time analysis and calculation of monitoring data can ensure the operational security of this section of China’s high-speed railway system.

  5. A conceptual Model for Highway Speed Monitoring and Enforcement in Zimbabwe

    Directory of Open Access Journals (Sweden)

    Furusa Samuel Simbarashe

    2016-10-01

    Full Text Available Many African countries lack resources and sophisticated technology needed to monitor and enforce traffic speed regulations in highway. These countries rely on highway patrolling which is a manual technique used to oversee and enforce the traffic safety compliance on the roads. The technique seems to be woeful and inadequate, since police officers can be bribed and the equipment they use does not provide enough evidence to empower independent auditors to quiz why certain offenders were not ticketed. Because of the need to have an up-to-date technology to monitor and enforce highway speed regulation, the purpose of this study was to suggest for the adoption of a conceptual model for highway speed monitoring and enforcement that incorporates Automatic Number Plate Recognition (ANPR, GSM and back-end integration. Using various models in traffic monitoring and regulation, a conceptual model was designed in order to reduce corruption and speed related accidents in Zimbabwe. The proposed model is expected to improve highway speed monitoring and enforcement in Zimbabwe and other countries that are still lagging in this regard.

  6. Effect of Rotational Speeds on the Cast Tube During Vertical Centrifugal Casting Process on Appearance, Microstructure, and Hardness Behavior for Al-2Si Alloy

    Science.gov (United States)

    Shailesh Rao, A.; Tattimani, Mahantesh S.; Rao, Shrikantha S.

    2015-04-01

    The flow of molten metal plays a crucial role in determining casting quality. During rotation of the mold, melt flow around its inner circumference determines the final configurations and properties of the cast tube. In this paper, Al-2Si alloy is cast in the vertical mold at the various rotational speeds of the mold. The uniform cylinder tube is formed at a rotational speed of 1000 rpm, while before and beyond this speed, irregular-shaped cast tube is formed. Finally, fine structured grain size with high hardness value is found in uniform cast tube compared with others.

  7. Vibration monitoring of EDF rotating machinery using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Alguindigue, I.E.; Loskiewicz-Buczak, A.; Uhrig, R.E. (Tennessee Univ., Knoxville, TN (United States). Dept. of Nuclear Engineering); Hamon, L.; Lefevre, F. (Electricite de France, 78 - Chatou (France). Direction des Etudes et Recherches)

    1991-01-01

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

  8. Vibration monitoring of EDF rotating machinery using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Alguindigue, I.E.; Loskiewicz-Buczak, A.; Uhrig, R.E. [Tennessee Univ., Knoxville, TN (United States). Dept. of Nuclear Engineering; Hamon, L.; Lefevre, F. [Electricite de France, 78 - Chatou (France). Direction des Etudes et Recherches

    1991-12-31

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

  9. High-Speed Video-Oculography for Measuring Three-Dimensional Rotation Vectors of Eye Movements in Mice

    Science.gov (United States)

    Takeda, Noriaki; Uno, Atsuhiko; Inohara, Hidenori; Shimada, Shoichi

    2016-01-01

    Background The mouse is the most commonly used animal model in biomedical research because of recent advances in molecular genetic techniques. Studies related to eye movement in mice are common in fields such as ophthalmology relating to vision, neuro-otology relating to the vestibulo-ocular reflex (VOR), neurology relating to the cerebellum’s role in movement, and psychology relating to attention. Recording eye movements in mice, however, is technically difficult. Methods We developed a new algorithm for analyzing the three-dimensional (3D) rotation vector of eye movement in mice using high-speed video-oculography (VOG). The algorithm made it possible to analyze the gain and phase of VOR using the eye’s angular velocity around the axis of eye rotation. Results When mice were rotated at 0.5 Hz and 2.5 Hz around the earth’s vertical axis with their heads in a 30° nose-down position, the vertical components of their left eye movements were in phase with the horizontal components. The VOR gain was 0.42 at 0.5 Hz and 0.74 at 2.5 Hz, and the phase lead of the eye movement against the turntable was 16.1° at 0.5 Hz and 4.88° at 2.5 Hz. Conclusions To the best of our knowledge, this is the first report of this algorithm being used to calculate a 3D rotation vector of eye movement in mice using high-speed VOG. We developed a technique for analyzing the 3D rotation vector of eye movements in mice with a high-speed infrared CCD camera. We concluded that the technique is suitable for analyzing eye movements in mice. We also include a C++ source code that can calculate the 3D rotation vectors of the eye position from two-dimensional coordinates of the pupil and the iris freckle in the image to this article. PMID:27023859

  10. Effects of the tool rotational speed and shoulder penetration depth on mechanical properties and failure modes of friction stir spot welds of aluminum 2024-T3 sheets

    Energy Technology Data Exchange (ETDEWEB)

    Paidar, Moslem; Khodabandeh, Alireza; Najafi, Hamidreza [Islamic Azad University, Tehran (Iran, Islamic Republic of); Roughaghdam, Alireza Sabour [Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2014-12-15

    In this work, friction stir spot welding with 1.6 mm thickness of the 2024-T3 aluminum alloy is carried out. The effects of the tool rotational speed and shoulder penetration depth on surface appearance, macrostructure, temperature profile, maximum failure load and failure modes are investigated. Results show that, the effect of the tool rotational speed on maximum tensile shear load is similar to the effect of the shoulder penetration depth, increasing tool rotational speed and shoulder penetration depth resulted in the increase of the tensile shear load. Maximum load of about 8282 N is obtained by using 1000 rpm rotational speed and 0.7 mm shoulder penetration depth. Observation of the failed specimens indicates two types of failure modes under tensile shear loading, the shear fracture that occurs in low shoulder penetration depths and tensile shear fracture that occurs in high shoulder penetration depths.

  11. Measurement Research of Motorized Spindle Dynamic Stiffness under High Speed Rotating

    Directory of Open Access Journals (Sweden)

    Xiaopeng Wang

    2015-01-01

    Full Text Available High speed motorized spindle has become a key functional unit of high speed machine tools and effectively promotes the development of machine tool technology. The development of higher speed and more power puts forward the stricter requirement for the performance of motorized spindle, especially the dynamic performance which affects the machining accuracy, reliability, and production efficiency. To overcome the problems of ineffective loading and dynamic performance measurement of motorized spindle, a noncontact electromagnetic loading device is developed. The cutting load can be simulated by using electromagnetic force. A new method of measuring force by force sensors is presented, and the steady and transient loading force could be measured exactly. After the high speed machine spindle is tested, the frequency response curves of the spindle relative to machine table are collected at 0~12000 rpm; then the relationships between stiffness and speeds as well as between damping ratio and speeds are obtained. The result shows that not only the static and dynamic stiffness but also the damping ratio declined with the increase of speed.

  12. Processing speed can monitor stimulant-medication effects in adults with attention deficit disorder with hyperactivity.

    Science.gov (United States)

    Nielsen, Niels Peter; Wiig, Elisabeth H; Bäck, Svante; Gustafsson, Jan

    2017-05-01

    Treatment responses to methylphenidate by adults with ADHD are generally monitored against DSM-IV/DSM-V symptomatology, rating scales or interviews during reviews. To evaluate the use of single- and dual-dimension processing-speed and efficiency measures to monitor the effects of pharmacological treatment with methylphenidate after a short period off medication. A Quick Test of Cognitive Speed (AQT) monitored the effects of immediate-release methylphenidate in 40 previously diagnosed and medicated adults with ADHD. Processing speed was evaluated with prior prescription medication, without medication after a 2-day period off ADHD medication, and with low-dose (10/20 mg) and high-dose (20/40 mg) methylphenidate hydrochloride (Medikinet IR). Thirty-three participants responded to the experimental treatments. One-way ANOVA with post-hoc analysis (Scheffe) indicated significant main effects for single dimension colour and form and dual-dimension colour-form naming. Post-hoc analysis indicated statistical differences between the no- and high-dose medication conditions for colour and form, measures of perceptual speed. For colour-form naming, a measure of cognitive speed, there was a significant difference between no- and low-dose medication and between no- and high-dose medications, but not between low- and high-dose medications. Results indicated that the AQT tests effectively monitored incremental effects of the methylphenidate dose on processing speed after a 2-day period off medication. Thus, perceptual (colour and form) and cognitive speed (two-dimensional colour-form naming) and processing efficiency (lowered shift costs) increased measurably with high-dose medication. These preliminary findings warrant validation with added measures of associated behavioural and cognitive changes.

  13. Effects of Simulated Microgravity on Otolith Growth of Larval Zebrafish using a Rotating-Wall Vessel: Appropriate Rotation Speed and Fish Developmental Stage

    Science.gov (United States)

    Li, Xiaoyan; Anken, Ralf; Liu, Liyue; Wang, Gaohong; Liu, Yongding

    2017-02-01

    Stimulus dependence is a general feature of developing animal sensory systems. In this respect, it has extensively been shown earlier that fish inner ear otoliths can act as test masses as their growth is strongly affected by altered gravity such as hypergravity obtained using centrifuges, by (real) microgravity achieved during spaceflight or by simulated microgravity using a ground-based facility. Since flight opportunities are scarce, ground-based simulators of microgravity, using a wide variety of physical principles, have been developed to overcome this shortcoming. Not all of them, however, are equally well suited to provide functional weightlessness from the perspective of the biosystem under evaluation. Therefore, the range of applicability of a particular simulator has to be extensively tested. Earlier, we have shown that a Rotating-Wall Vessel (RWV) can be used to provide simulated microgravity for developing Zebrafish regarding the effect of rotation on otolith development. In the present study, we wanted to find the most effective speed of rotation and identify the appropriate developmental stage of Zebrafish, where effects are the largest, in order to provide a methodological basis for future in-depth analyses dedicated to the physiological processes underlying otolith growth at altered gravity. Last not least, we compared data on the effect of simulated microgravity on the size versus the weight of otoliths, since the size usually is measured in related studies due to convenience, but the weight more accurately approximates the physical capacity of an otolith. Maintaining embryos at 10 hours post fertilization for three days in the RWV, we found that 15 revolutions per minute (rpm) yielded the strongest effects on otolith growth. Maintenance of Zebrafish staged at 10 hpf, 1 day post fertilization (dpf), 4 dpf, 7 dpf and 14 dpf for three days at 15 rpm resulted in the most prominent effects in 7 dpf larvae. Weighing versus measuring the size of otoliths

  14. Effects of Simulated Microgravity on Otolith Growth of Larval Zebrafish using a Rotating-Wall Vessel: Appropriate Rotation Speed and Fish Developmental Stage

    Science.gov (United States)

    Li, Xiaoyan; Anken, Ralf; Liu, Liyue; Wang, Gaohong; Liu, Yongding

    2016-10-01

    Stimulus dependence is a general feature of developing animal sensory systems. In this respect, it has extensively been shown earlier that fish inner ear otoliths can act as test masses as their growth is strongly affected by altered gravity such as hypergravity obtained using centrifuges, by (real) microgravity achieved during spaceflight or by simulated microgravity using a ground-based facility. Since flight opportunities are scarce, ground-based simulators of microgravity, using a wide variety of physical principles, have been developed to overcome this shortcoming. Not all of them, however, are equally well suited to provide functional weightlessness from the perspective of the biosystem under evaluation. Therefore, the range of applicability of a particular simulator has to be extensively tested. Earlier, we have shown that a Rotating-Wall Vessel (RWV) can be used to provide simulated microgravity for developing Zebrafish regarding the effect of rotation on otolith development. In the present study, we wanted to find the most effective speed of rotation and identify the appropriate developmental stage of Zebrafish, where effects are the largest, in order to provide a methodological basis for future in-depth analyses dedicated to the physiological processes underlying otolith growth at altered gravity. Last not least, we compared data on the effect of simulated microgravity on the size versus the weight of otoliths, since the size usually is measured in related studies due to convenience, but the weight more accurately approximates the physical capacity of an otolith. Maintaining embryos at 10 hours post fertilization for three days in the RWV, we found that 15 revolutions per minute (rpm) yielded the strongest effects on otolith growth. Maintenance of Zebrafish staged at 10 hpf, 1 day post fertilization (dpf), 4 dpf, 7 dpf and 14 dpf for three days at 15 rpm resulted in the most prominent effects in 7 dpf larvae. Weighing versus measuring the size of otoliths

  15. Fault Detection in Gear Drives with Non-Stationary Rotational Speed-Part i: the Time-Frequency Approach

    Science.gov (United States)

    Meltzer, G.; Ivanov, Yu Ye

    2003-09-01

    This paper deals with the recognition of faults in toothing during non-stationary start-up and run-down of gear drives. In the first part, this task will be solved by means of the time-frequency analysis. As a practical case study, we investigated a planetary gear for passenger cars. New exponental smoothing kernels which respect to the known-in-advance angular acceleration of gear drive were created. These kernels must be adapted in the case of an in-advance-unknown course of rotational speed.

  16. Detection of biomolecules and bioconjugates by monitoring rotated grating-coupled surface plasmon resonance

    CERN Document Server

    Szalai, Aniko; Somogyi, Aniko; Szenes, Andras; Banhelyi, Balazs; Csapo, Edit; Dekany, Imre; Csendes, Tibor; Csete, Maria

    2016-01-01

    Plasmonic biosensing chips were prepared by fabricating wavelength-scaled dielectric-metal interfacial gratings on thin polycarbonate films covered bimetal layers via two-beam interference laser lithography. Lysozyme (LYZ) biomolecules and gold nanoparticle (AuNP-LYZ) bioconjugates with 1:5 mass ratio were seeded onto the biochip surfaces. Surface plasmon resonance spectroscopy was performed before and after biomolecule seeding in a modified Kretschmann-arrangement by varying the azimuthal and polar angles to optimize the conditions for rotated grating-coupling. The shift of secondary and primary resonance peaks originating from rotated grating-coupling phenomenon was monitored to detect the biomolecule and bioconjugate adherence. Numerical calculations were performed to reproduce the measured reflectance spectra and the resonance peak shifts caused by different biocoverings. Comparison of measurements and calculations proved that monitoring the narrower secondary peaks under optimal rotated-grating coupling ...

  17. A SysML Test Model and Test Suite for the ETCS Ceiling Speed Monitor

    DEFF Research Database (Denmark)

    Braunstein, Cécile; Peleska, Jan; Schulze, Uwe

    2014-01-01

    In this technical report a detailed model description of a train control system application is given. The application consists of the ceiling speed monitoring (CSM) function for the European Vital Computer which is the main onboard controller for trains conforming to the European Train Control Sy...

  18. The Development of Hi-Speed Punching System Using A Couple of Rotating Bodies

    Institute of Scientific and Technical Information of China (English)

    Shinichi; Taya; Keiichi; Shimizu

    2002-01-01

    Punched steel sheets (metal sheets or foils) as thi n as 0.1mm are quite useful in the field of filters and various precision instrume nts. Thus, we have to develop more accurate and speedy techniques for punching t hin sheets. The traditional punching method uses an up-down pressing motion of a punch or a die on a strip of metal. The efficiency of this method is determine d by the speed of the motion. In the case of punching a sequence of tiny holes w ith a few millimeters' interval, the speed of feeding...

  19. MAXIMIZING HEIGHT, DISTANCE OR ROTATION FROM REAL-TIME ANALYSIS VISUALISATION OF TAKE-OFF ANGLES AND SPEED

    Directory of Open Access Journals (Sweden)

    Richard Green

    2006-12-01

    Full Text Available Studies to optimise take off angles for height or distance have usually involved either a time-consuming invasive approach of placing markers on the body in a laboratory setting or using even less efficient manual frame-by-frame joint angle calculations with one of the many sport science video analysis software tools available. This research introduces a computer-vision based, marker-free, real-time biomechanical analysis approach to optimise take-off angles based on speed, base of support and dynamically calculated joint angles and mass of body segments. The goal of a jump is usually for height, distance or rotation with consequent dependencies on speed and phase of joint angles, centre of mass COM and base of support. First and second derivatives of joint angles and body part COMs are derived from a Continuous Human Movement Recognition (CHMR system for kinematical and what-if calculations. Motion is automatically segmented using hierarchical Hidden Markov Models and 3D tracking is further stabilized by estimating the joint angles for the next frame using a forward smoothing Particle filter. The results from a study of jumps, leaps and summersaults supporting regular knowledge of results feedback during training sessions indicate that this approach is useful for optimising the height, distance or rotation of skills

  20. Optical properties of thin flms of MEH-PPV produced by the spin-coating technique at different rotational speeds

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Soares Guimarães

    2008-08-01

    Full Text Available We present a study on the optical properties of thin flms of poly[2-methoxy-5-(20-ethyl-hexyloxy-1,4-phenylene vinylene] (MEH-PPV produced at a concentration of 10 mg/ml xylene. The solution was deposited onto glass substrates by the spin-coating technique at different rotational speeds (300, 1000 and 4000 rpm. We study the effect of rotational speeds on the sample at 300 K, by analyzing the photoluminescence (PL spectra at different points of the polymeric flm. We also analyze the effects of the excitation power on the optical behavior of MEH-PPV at 300 K. At low temperatures the PL spectra of sample A1000 (1000 rpm show a narrow peak for the electronic transition and a series of vibronic sidebands which reveal the electron coupling with two different vibronic modes. In the temperature range of 130 K to 290 K, we analyze systematically the transition lineshapes in the optical spectra using Gaussian curves.

  1. Influence of high rotational speeds on heat transfer and oil film thickness in aero-engine bearing chambers

    Science.gov (United States)

    Wittig, S.; Glahn, A.; Himmelsbach, J.

    1994-04-01

    Increasing the thermal loading of bearing chambers in modern aero-engines requires advanced techniques for the determination of heat transfer characteristics. In the present study, film thickness and heat transfer measurements have been carried out for the complex two-phase oil/air flow in bearing chambers. In order to ensure real engine conditions, a new test facility has been built up, designed for rotational speeds up to n = 16,000 rpm and maximum flow temperatures of T(sub max) = 473 K. Sealing air and lubrication oil flow can be varied nearly in the whole range of aero-engine applications. Special interest is directed toward the development of an ultrasonic oil film thickness measuring technique, which can be used without any reaction on the flow inside the chamber. The determination of local heat transfer at the bearing chamber housing is based on a well-known temperature gradient method using surface temperature measurements and a finite element code to determine temperature distributions within the bearing chamber housing. The influence of high rotational speed on the local heat transfer and the oil film thickness is discussed.

  2. Exploration of combined adjustment laws about IGV,stator and rotational speed in off-design conditions in an axial compressor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Experimental investigations are performed in a three-stage low-speed axial compressor with variable inlet guide vanes(IGV) and adjustable stators.The characteristics of the compressor,especially the efficiency and stall margin,are analyzed in design and off-design operation conditions by adjusting stagger angles of IGV and stators as well as changing the rotational speed.The experimental results show that the off-design performance of the multistage axial compressor is improved by restaggering of IGV and stators related to rotational speed.Considering the background of engineering applications,digital signal processing(DSP) technique is used to realize online adjustment of stagger angles according to the corresponding relations between incidence angles of rotor and rotational speed.

  3. Acoustic emission-based condition monitoring methods: Review and application for low speed slew bearing

    Science.gov (United States)

    Caesarendra, Wahyu; Kosasih, Buyung; Tieu, Anh Kiet; Zhu, Hongtao; Moodie, Craig A. S.; Zhu, Qiang

    2016-05-01

    This paper presents an acoustic emission-based method for the condition monitoring of low speed reversible slew bearings. Several acoustic emission (AE) hit parameters as the monitoring parameters for the detection of impending failure of slew bearings are reviewed first. The review focuses on: (1) the application of AE in typical rolling element bearings running at different speed classifications, i.e. high speed (>600 rpm), low speed (10-600 rpm) and very low speed (<10 rpm); (2) the commonly used AE hit parameters in rolling element bearings and (3) AE signal processing, feature extraction and pattern recognition methods. In the experiment, impending failure of the slew bearing was detected by the AE hit parameters after the new bearing had run continuously for approximately 15 months. The slew bearing was then dismantled and the evidence of the early defect was analysed. Based on the result, we propose a feature extraction method of the AE waveform signal using the largest Lyapunov exponent (LLE) algorithm and demonstrate that the LLE feature can detect the sign of failure earlier than the AE hit parameters with improved prediction of the progressive trend of the defect.

  4. Compound faults detection of rolling element bearing based on the generalized demodulation algorithm under time-varying rotational speed

    Science.gov (United States)

    Zhao, Dezun; Li, Jianyong; Cheng, Weidong; Wen, Weigang

    2016-09-01

    Multi-fault detection of the rolling element bearing under time-varying rotational speed presents a challenging issue due to its complexity, disproportion and interaction. Computed order analysis (COA) is one of the most effective approaches to remove the influences of speed fluctuation, and detect all the features of multi-fault. However, many interference components in the envelope order spectrum may lead to false diagnosis results, in addition, the deficiencies of computational accuracy and efficiency also cannot be neglected. To address these issues, a novel method for compound faults detection of rolling element bearing based on the generalized demodulation (GD) algorithm is proposed in this paper. The main idea of the proposed method is to exploit the unique property of the generalized demodulation algorithm in transforming an interested instantaneous frequency trajectory of compound faults bearing signal into a line paralleling to the time axis, and then the FFT algorithm can be directly applied to the transformed signal. This novel method does not need angular resampling algorithm which is the key step of the computed order analysis, and is hence free from the deficiencies of computational error and efficiency. On the other hand, it only acts on the instantaneous fault characteristic frequency trends in envelope signal of multi-fault bearing which include rich fault information, and is hence free from irrelevant items interferences. Both simulated and experimental faulty bearing signal analysis validate that the proposed method is effective and reliable on the compound faults detection of rolling element bearing under variable rotational speed conditions. The comprehensive comparison with the computed order analysis further shows that the proposed method produces higher accurate results in less computation time.

  5. LIDAR wind speed measurements from a rotating spinner (SpinnerEx 2009)

    DEFF Research Database (Denmark)

    Angelou, Nikolas; Mikkelsen, Torben; Hansen, Kasper Hjorth

    spinner of a MW-sized wind turbine, and investigate the approaching wind fields from this vantage point. Time series of wind speed measurements from the lidar with 50 Hz sampling rate were successfully obtained for approximately 60 days, during the measurement campaign lasting from April to August 2009...... and the wind turbine’s yaw relative to the mean wind speed direction. The data analysis processes are documented. A methodology for the calculation of the yaw misalignment of the wind turbine relative to the wind direction, as a function of various averaging times, is proposed, using the lidar’s instantaneous...... the lidar measurements. Data from an adjacent meteorological mast as well as data logged within the wind turbine’s control system were used to evaluate the results....

  6. Rotor speed estimation of induction machines by monitoring the stator voltages and currents

    Energy Technology Data Exchange (ETDEWEB)

    Ho, S.Y.S.; Langman, R.A. [Tasmania Univ., Hobart, TAS (Australia)

    1995-12-31

    Accurate measurement of induction motor speed is routinely obtained by using a transducer coupled on the shaft. In many industrial situations, this is not acceptable as there may be no room for a suitable transducer, or else the motor environment may be too unpleasant. It is in theory possible to calculate the speed by monitoring the terminal voltages and currents (plus knowing the angular synchronous speed) and then applying these to the differential equations of motor. Two rotor speed algorithms were investigated. Unsatisfactory results were obtained with an algorithm based on the machine equations in a stationary reference frame because at some stage the algorithm divides zero by zero. To avoid these problems the time varying stator voltages and currents were further transformed into the synchronous reference frame so that they end up with dc electrical quantities. This algorithm of obtaining the tangent of the phase angle, for the determination of the rotor speed, was discussed and tested. The analysis presented in this paper points out that the speed of induction motor may be estimated at about +- 0.1 percent uncertainty from measurement of the stator voltage and current. (author). 5 figs., 5 refs.

  7. Improving the Precision and Speed of Euler Angles Computation from Low-Cost Rotation Sensor Data

    Directory of Open Access Journals (Sweden)

    Aleš Janota

    2015-03-01

    Full Text Available This article compares three different algorithms used to compute Euler angles from data obtained by the angular rate sensor (e.g., MEMS gyroscope—the algorithms based on a rotational matrix, on transforming angular velocity to time derivations of the Euler angles and on unit quaternion expressing rotation. Algorithms are compared by their computational efficiency and accuracy of Euler angles estimation. If attitude of the object is computed only from data obtained by the gyroscope, the quaternion-based algorithm seems to be most suitable (having similar accuracy as the matrix-based algorithm, but taking approx. 30% less clock cycles on the 8-bit microcomputer. Integration of the Euler angles’ time derivations has a singularity, therefore is not accurate at full range of object’s attitude. Since the error in every real gyroscope system tends to increase with time due to its offset and thermal drift, we also propose some measures based on compensation by additional sensors (a magnetic compass and accelerometer. Vector data of mentioned secondary sensors has to be transformed into the inertial frame of reference. While transformation of the vector by the matrix is slightly faster than doing the same by quaternion, the compensated sensor system utilizing a matrix-based algorithm can be approximately 10% faster than the system utilizing quaternions (depending on implementation and hardware.

  8. Improving the precision and speed of Euler angles computation from low-cost rotation sensor data.

    Science.gov (United States)

    Janota, Aleš; Šimák, Vojtech; Nemec, Dušan; Hrbček, Jozef

    2015-03-23

    This article compares three different algorithms used to compute Euler angles from data obtained by the angular rate sensor (e.g., MEMS gyroscope)-the algorithms based on a rotational matrix, on transforming angular velocity to time derivations of the Euler angles and on unit quaternion expressing rotation. Algorithms are compared by their computational efficiency and accuracy of Euler angles estimation. If attitude of the object is computed only from data obtained by the gyroscope, the quaternion-based algorithm seems to be most suitable (having similar accuracy as the matrix-based algorithm, but taking approx. 30% less clock cycles on the 8-bit microcomputer). Integration of the Euler angles' time derivations has a singularity, therefore is not accurate at full range of object's attitude. Since the error in every real gyroscope system tends to increase with time due to its offset and thermal drift, we also propose some measures based on compensation by additional sensors (a magnetic compass and accelerometer). Vector data of mentioned secondary sensors has to be transformed into the inertial frame of reference. While transformation of the vector by the matrix is slightly faster than doing the same by quaternion, the compensated sensor system utilizing a matrix-based algorithm can be approximately 10% faster than the system utilizing quaternions (depending on implementation and hardware).

  9. Temporal and spatial strategies in an active place avoidance task on Carousel: a study of effects of stability of arena rotation speed in rats

    Directory of Open Access Journals (Sweden)

    Štěpán Bahník

    2015-09-01

    Full Text Available The active place avoidance task is a dry-arena task used to assess spatial navigation and memory in rodents. In this task, a subject is put on a rotating circular arena and avoids an invisible sector that is stable in relation to the room. Rotation of the arena means that the subject’s avoidance must be active, otherwise the subject will be moved in the to-be-avoided sector by the rotation of the arena and a slight electric shock will be administered. The present experiment explored the effect of variable arena rotation speed on the ability to avoid the to-be-avoided sector. Subjects in a group with variable arena rotation speed learned to avoid the sector with the same speed and attained the same avoidance ability as rats in a group with a stable arena rotation speed. Only a slight difference in preferred position within the room was found between the two groups. No difference was found between the two groups in the dark phase, where subjects could not use orientation cues in the room. Only one rat was able to learn the avoidance of the to-be-avoided sector in this phase. The results of the experiment suggest that idiothetic orientation and interval timing are not crucial for learning avoidance of the to-be-avoided sector. However, idiothetic orientation might be sufficient for avoiding the sector in the dark.

  10. Comparative study of the influence of cavity preparation with high-speed rotation or Er:YAG laser on infiltration of aesthetic restorations

    Science.gov (United States)

    Costa, D. P. T. S.; Beatrice, L. C. S.; Guerra, L. S. C.; Ribeiro, M. A.; Zanin, F. A. A.; Queiroga, A. S.; Limeira Júnior, F. A.; Gerbi, M. E. M. M.

    2010-04-01

    The aim of the present study was to compare marginal infiltration in Class V cavities prepared on extracted human premolars with either high-speed rotation or a Er:YAG laser. Class V cavities were executed on the vestibular and lingual faces of twelve premolars, with high-speed rotation or a Er:YAG laser (300 mJ, 4 Hz, and 3 W), and cavity surfaces were conditioned with 37% phosphoric acid combined with laser treatment (80 mJ, 5 Hz, 3 W) or without laser treatment in the following manner: G1—high-speed rotation + conditioning with phosphoric acid; G2—high-speed rotation + conditioning with laser and phosphoric acid; G3—laser + conditioning with phosphoric acid; and G4—laser + conditioning with laser and phosphoric acid. Specimens were restored with the composite resin, thermocycled and immersed in 0.5% basic fuchsin for 24 h. Specimens were then cross-cut and analyzed using a stereoscopic magnifying glass. Evaluations were submitted to the Kruskall-Wallis statistical test. No significant differences were found between the averages of the groups ( p > 0.05). High-speed rotation and Er:YAG laser for the confection of cavity preparation exhibited a similar performance with regard to marginal infiltration.

  11. The design of liquid drip speed monitoring device system based on MCU

    Science.gov (United States)

    Zheng, Shiyong; Li, Zhao; Li, Biqing

    2017-08-01

    This page proposed an intelligent transfusion control and monitoring system which designed by using AT89S52 micro controller as the core, using the keyboard and photoelectric sensor as the input module, digital tube and motor as the output module. The keyboard is independent and photoelectric sensor can offer reliable detection for liquid drop speed and the transfusion bottle page. When the liquid amount is less than the warning value, the system sounded the alarm, you can remove the alert by hand movement. With the advantages of speed controllable and input pulse power can be maintained of the motor, the system can control the bottle through the upper and lower slow-moving liquid drip to control the speed of intelligent purpose.

  12. Change Regularity of Rotation Speed of Impulse Correction Projectile%脉冲修正弹转速的变化规律

    Institute of Scientific and Technical Information of China (English)

    杨红伟; 甘明刚

    2011-01-01

    To research the change regularity of projectile rotation speed in trajectory correction process, the influence factors of rotation speed were studied based on angular motion equations of impulse correction projectile. The balanced rotation speed was deduced after impulse correction.According to the characteristic of correction trajectory,the change regularity of rotation speed of projectile after impulse action was obtained. The study result indicates that the radial eccentricity caused by the impulse action is the main factor which causes the large change of rotation speed.The change degree of rotation speed is concerned with the magnitude of impulse, the radial eccentric distance and the number of working impulse motor,and the process that the speed goes equilibrium is independent of the impulse.%为研究弹道修正过程中弹丸转速的变化情况,在建立脉冲修正弹角运动方程组的基础上,分析了转速变化的影响因素,推导了脉冲修正后弹丸的平衡转速.根据修正弹道的特点给出了脉冲结束后弹丸转速的变化规律.研究表明,脉冲作用的径向偏心是造成弹丸转速大幅变化的主要原因,转速变化的剧烈程度与脉冲冲量大小、径向偏心距及脉冲发动机工作个数有关;转速趋于平衡转速的渐进过程与脉冲作用无关.

  13. Dynamic coefficients of axial spline couplings in high-speed rotating machinery

    Energy Technology Data Exchange (ETDEWEB)

    Ku, C.P.R.; Walton, J.F. Jr. (Mechanical Technology Inc., Latham, NY (United States)); Lund, J.W. (Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Machine Elements)

    1994-07-01

    This paper provided the first opportunity to quantify the angular stiffness and equivalent viscous damping coefficients of an axial spline coupling used in high-speed turbomachinery. The bending moments and angular deflections transmitted across an axial spline coupling were measured while a nonrotating shaft was excited by an external shaker. A rotordynamics computer program was used to simulate the test conditions and to correlate the angular stiffness and damping coefficients. The effects of external force and frequency were also investigated. The angular stiffness and damping coefficients were used to perform a linear steady-state rotordynamics stability analysis, and the unstable natural frequency was calculated and compared to the experimental measurements.

  14. Sensor Networks Hierarchical Optimization Model for Security Monitoring in High-Speed Railway Transport Hub

    Directory of Open Access Journals (Sweden)

    Zhengyu Xie

    2015-01-01

    Full Text Available We consider the sensor networks hierarchical optimization problem in high-speed railway transport hub (HRTH. The sensor networks are optimized from three hierarchies which are key area sensors optimization, passenger line sensors optimization, and whole area sensors optimization. Case study on a specific HRTH in China showed that the hierarchical optimization method is effective to optimize the sensor networks for security monitoring in HRTH.

  15. Influence of the relative rotational speed on component features in micro rotary swaging

    Directory of Open Access Journals (Sweden)

    Ishkina Svetlana

    2015-01-01

    Full Text Available Micro rotary swaging is a cold forming process for production of micro components with determined geometry and surface. It is also possible to change the microstructure of wires and hence the material properties. Swaging dies revolve around the work piece with an overlaid radial oscillation. Newly developed tools (Flat Surface Dies, FSD feature plain surfaces and do not represent the geometry of the formed part as in conventional swaging. Using these tools allows for producing wires with triangle geometry (cross section as well as a circular shape. To test the influence of FSD on material properties by micro swaging a new method is investigated: the variation of the relative speed between the specimen and dies in infeed rotary swaging. During this specific process copper (C11000 and steel (304 Alloy wires with diameter d0 = 1 mm are formed. It is noticed that the mechanical characteristics such as ductility and strength differ from the characteristics after conventional swaging. Moreover this approach enables new possibilities to influence the geometry and the surface quality of wires. The impact of the relative speed on the processed wire features is described in this paper.

  16. Evaluation of tensile strength and fracture behavior of friction welded dissimilar steels under different rotational speeds and axial pressures

    Indian Academy of Sciences (India)

    Amit Handa; Vikas Chawla

    2015-08-01

    In the present study an attempt was made to join austenitic stainless steel (AISI 304) with low alloy steel (AISI 1021) at five different rotational speeds ranging from 800 to 1600 rpm and at as many different axial pressures ranging from 75 MPa to 135 MPa and then determining the strength of the joint by means of tensile strength. Furthermore scanning electron microscope analysis was performed to evaluate the pattern of failure at the fractured locations, also the micro hardness was checked at the weld interface and at distances on either side of the weld joint to evaluate the effect of heat. The highest tensile strength achieved by the welded specimens was 1.8% higher than the AISI 1021 steel and the lowest tensile strength obtained was 20% lower than the parent AISI 1021.

  17. An Improvement of Scanning Ellipsometer by Rotating a Polarizer and an Analyzer at a Speed Ratio of 1:3

    Science.gov (United States)

    El-Agez, Taher M.; Taya, Sofyan A.; El Tayyan, Ahmed A.

    2011-03-01

    We propose theoretically an improved spectroscopic ellipsometer to study the optical properties of solids. In this system, the polarizer and the analyzer are rotating synchronously in the same direction at a speed ratio 1:3. The light intensity received by the detector contains six Fourier coefficients, one dc and five ac. One can independently extract the ellipsometric parameters as well as the optical constants of a sample using any of six different sets of the Fourier coefficients. A comparison among these sets is presented to find the optimal set corresponding to the minimum percent error in the calculation of the real and imaginary parts of the dielectric function. The results from the simulated spectra of the complex refractive index of c-Si, ZnSe, and GaP are presented.

  18. Microstructures in Centrifugal Casting of SiCp/AlSi9Mg Composites with Different Mould Rotation Speeds

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; SUN Wenju; LI Bo; XUIE Hansong; LIU Changming

    2011-01-01

    Two ingots were produced by centrifugal casting at mould rotational speeds of 600 rpm and 800 rpm using 20 vol% SiCp/AlSi9Mg composite melt, respectively. The microstructure along the radial direction of cross-sectional sample of ingots was presented. SiC particles migrated towards the external circumference of the tube, and the distribution of SiC particles became uniform under centrifugal force. Voids in 20 vol% SiCp/AlSi9Mg composite melt migrated towards the inner circumference of the tube. The quantitative analysis results indicated that not only SiC particles but also primary a phases segregated greatly in centrifugal casting resulting from the transportation behavior of constitutions with different densities in the SiCp/AlSi9Mg composite melt. In addition, the eutectic Si was broken owing to the motion of SiCp/AlSi9Mg composite melt during centrifugal casting.

  19. Effect of Traverse/Rotational Speed on Material Deformations and Temperature Distributions in Friction Stir Welding

    Institute of Scientific and Technical Information of China (English)

    Zhao ZHANG; Jun BIE; Yali LIU; Hongwu ZHANG

    2008-01-01

    A fully coupled thermo-mechanical model was developed to study the temperature fields and the plastic deformations of alloy AL6061-T6 under different process parameters during the friction stir welding (FSW) process.Three-dimensional results under different process parameters were presented.Results indicate that the maximum temperature is lower than the melting point of the welding material.The higher temperature gradient occurs in the leading side of the workpiece.The calculated temperature field can be fitted well with the one from the experimental test.A lower plastic strain region can be found near the welding tool in the trailing side on the bottom surface,which is formed by the specific material flow patterns in FSW.The maximum temperature can be increased with increasing the welding speed and the angular velocity in the current numerical modelling.

  20. Increased speed of rotation for the smallest light-driven molecular motor.

    Science.gov (United States)

    ter Wiel, Matthijs K J; van Delden, Richard A; Meetsma, Auke; Feringa, Ben L

    2003-12-10

    In this paper we present the smallest artificial light-driven molecular motor consisting of only 28 carbon and 24 hydrogen atoms. The concept of controlling directionality of rotary movement at the molecular level by introduction of a stereogenic center next to the central olefinic bond of a sterically overcrowded alkene does not only hold for molecular motors with six-membered rings, but is also applicable to achieve the unidirectional movement for molecular motors having five-membered rings. Although X-ray analyses show that the five-membered rings in the cis- and trans-isomer of the new molecular motor are nearly flat, the energy differences between the (pseudo-)diaxial and (pseudo-)diequatorial conformations of the methyl substituents in both isomers are still large enough to direct the rotation of one-half of the molecule with respect to the other half in a clockwise fashion. The full rotary cycle comprises four consecutive steps: two photochemical isomerizations each followed by a thermal helix inversion. Both photochemical cis-trans isomerizations proceed with a preference for the unstable diequatorial isomers over the stable diaxial isomers. The thermal barriers for helix inversion of this motor molecule have decreased dramatically compared to its six-membered ring analogue, the half-life of the fastest step being only 18 s at room temperature.

  1. Effect of Traverse and Rotational Speeds on the Tensile Behavior of the Underwater Dissimilar Friction Stir Welded Aluminum Alloys

    Science.gov (United States)

    Bijanrostami, Kh.; Barenji, R. Vatankhah; Hashemipour, M.

    2017-01-01

    The tensile behavior of the underwater dissimilar friction stir welded AA6061 and AA7075 aluminum alloy joints was investigated for the first time. For this aim, the joints were welded at different conditions and tensile test was conducted for measuring the strength and elongation of them. In addition, the microstructure of the joints was characterized by means of optical and transmission electron microscopes. Scanning electron microscope was used for fractography of the joints. Furthermore, the process parameters and tensile properties of the joints were correlated and optimized. The results revealed that the maximum tensile strength of 237.3 MPa and elongation of 41.2% could be obtained at a rotational speed 1853 rpm and a traverse speed of 50 mm/min. In comparison with the optimum condition, higher heat inputs caused grain growth and reduction in dislocation density and hence led to lower strength. The higher elongations for the joints welded at higher heat inputs were due to lower dislocation density inside the grains, which was consistent with a more ductile fracture of them.

  2. Worker selection of safe speed and idle condition in simulated monitoring of two industrial robots.

    Science.gov (United States)

    Karwowski, W; Rahimi, M

    1991-05-01

    Industrial robots often operate at high speed, with unpredictable motion patterns and erratic idle times. Serious injuries and deaths have occurred due to operator misperception of these robot design and performance characteristics. The main objective of the research project was to study human perceptual aspects of hazardous robotics workstations. Two laboratory experiments were designed to investigate workers' perceptions of two industrial robots with different physical configurations and performance capabilities. Twenty-four subjects participated in the study. All subjects were chosen from local industries, and had had considerable exposure to robots and other automated equipment in their working experience. Experiment 1 investigated the maximum speed of robot arm motions that workers, who were experienced with operation of industrial robots, judged to be 'safe' for monitoring tasks. It was found that the selection of safe speed depends on the size of the robot and the speed with which the robot begins its operation. Speeds of less than 51 cm/s and 63 cm/s for large and small robots, respectively, were perceived as safe, i.e., ones that did not result in workers feeling uneasy or endangered when working in close proximity to the robot and monitoring its actions. Experiment 2 investigated the minimum value of robot idle time (inactivity) perceived by industrial workers as system malfunction, and an indication of the 'safe-to-approach' condition. It was found that idle times of 41 s and 28 s or less for the small and large robots, respectively, were perceived by workers to be a result of system malfunction. About 20% of the workers waited only 10 s or less before deciding that the robot had stopped because of system malfunction. The idle times were affected by the subjects' prior exposure to a simulated robot accident. Further interpretations of the results and suggestions for operational limitations of robot systems are discussed.

  3. Determination of optimum rotational speed of heterogeneous catalytic reactor using computational fluid dynamic

    Directory of Open Access Journals (Sweden)

    Rungrote Kokoo

    2008-09-01

    Full Text Available Solid suspension in a stirrer tank reactor is relevant in many chemical process industries. For a heterogeneous catalyticreactor, the degree of solid suspension is a crucial parameter in the design and scaling-up processes. The suspension of solid catalysts at a minimum impeller speed can reduce the operating cost of processes. To ensure optimum conditions for suspension, a 3D simulation technique by Computational Fluid Dynamic (CFD was used to study flow characteristics in a heterogeneous catalytic reactor. A case study of a 200 milliliter cylindrical reactor was modeled together with equipped parts, i.e. a sampling port, 2 baffles, one thermocouple and a mechanical stirrer. The results show that the total velocity increases from the impeller’s center to the impeller’s tip and decreases from the impeller’s tip to the side wall of the reactor. The vertical velocity at the bottom of the impellers directs flow upward while the velocity at the top directs flow downward. These simulations provide a good preview of solid suspension without doing experiments. It is recommended that the vertical velocity at thebottom of the reactor is in the range between minimum fluidization velocity and terminal velocity to ensure solid suspension inthe system.

  4. An analysis of peak pelvis rotation speed, gluteus maximus and medius strength in high versus low handicap golfers during the golf swing.

    Science.gov (United States)

    Callaway, Sarahann; Glaws, Kate; Mitchell, Melissa; Scerbo, Heather; Voight, Michael; Sells, Pat

    2012-06-01

    The kinematic sequence of the golf swing is an established principle that occurs in a proximal-to-distal pattern with power generation beginning with rotation of the pelvis. Few studies have correlated the influence of peak pelvis rotation to the skill level of the golfer. Furthermore, minimal research exists on the strength of the gluteal musculature and their ability to generate power during the swing. The purpose of this study was to explore the relationship between peak pelvis rotation, gluteus medius and gluteus maximus strength, and a golfer's handicap. 56 healthy subjects. Each subject was assessed using a hand-held dynamometry device per standardized protocol to determine gluteus maximus and medius strength. The K-vest was placed on the subject with electromagnetic sensors at the pelvis, upper torso, and gloved lead hand to measure the rotational speed at each segment in degrees/second. After K-vest calibration and 5 practice swings, each subject hit 5 golf balls during which time, the sensors measured pelvic rotation speed. A one-way ANOVA was performed to determine the relationships between peak pelvis rotation, gluteus medius and gluteus maximus strength, and golf handicap. A significant difference was found between the following dependent variables and golf handicap: peak pelvis rotation (p=0.000), gluteus medius strength (p=0.000), and gluteus maximus strength (p=0.000). Golfers with a low handicap are more likely to have increased pelvis rotation speed as well as increased gluteus maximus and medius strength when compared to high handicap golfers. The relationships between increased peak pelvis rotation and gluteus maximus and medius strength in low handicap golfers may have implications in designing golf training programs. Further research needs to be conducted in order to further explore these relationships.

  5. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

    Directory of Open Access Journals (Sweden)

    You-Liang Ding

    2015-01-01

    Full Text Available Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge’s abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

  6. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

    Science.gov (United States)

    Wu, Lai-Yi

    2015-01-01

    Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature. PMID:26451387

  7. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure.

    Science.gov (United States)

    Ding, You-Liang; Wang, Gao-Xin; Sun, Peng; Wu, Lai-Yi; Yue, Qing

    2015-01-01

    Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

  8. High speed turboprop aeroacoustic study (single rotation). Volume 1: Model development

    Science.gov (United States)

    Whitfield, C. E.; Gliebe, P. R.; Mani, R.; Mungur, P.

    1989-01-01

    A frequency-domain noncompact-source theory for the steady loading and volume-displacement (thickness) noise of high speed propellers has been developed and programmed. Both near field and far field effects have been considered. The code utilizes blade surface pressure distributions obtained from three-dimensional nonlinear aerodynamic flow field analysis programs as input for evaluating the steady loading noise. Simplified mathematical models of the velocity fields induced at the propeller disk by nearby wing and fuselage surfaces and by angle-of-attack operation have been developed to provide estimates of the unsteady loading imposed on the propeller by these potential field type interactions. These unsteady blade loadings have been coupled to a chordwise compact propeller unsteady loading noise model to provide predictions of unsteady loading noise caused by these installation effects. Finally, an analysis to estimate the corrections to be applied to the free-field noise predictions in order to arrive at the measurable fuselage sound pressure levels has been formulated and programmed. This analysis considers the effects of fuselage surface reflection and diffraction together with surface boundary layer refraction. The steady loading and thickness model and the unsteady loading model have been verified using NASA-supplied data for the SR-2 and SR-3 model propfans. In addition, the steady loading and thickness model has been compared with data from the SR-6 model propfan. These theoretical models have been employed in the evaluation of the SR-7 powered Gulfstream aircraft in terms of noise characteristics at representative takeoff, cruise, and approach operating conditions. In all cases, agreement between theory and experiment is encouraging.

  9. The diagnostic line: A novel criterion for condition monitoring of rotating machinery.

    Science.gov (United States)

    Lin, Jinshan; Dou, Chunhong

    2015-11-01

    This study examined scaling properties of an increment series from rotating machinery. Moreover, two fluctuation parameters for the smallest and largest time scales of a scaling range served as a pair of fluctuation parameters to describe system conditions. Therefore, an interesting phenomenon is observed: the data points, each representing a pair of fluctuation parameters, for fault conditions almost form a straight line, while those for normal clearly depart from the straight line. To describe the phenomenon, a novel concept termed the diagnostic line was introduced. Subsequently, properties of the diagnostic line were carefully investigated theoretically and numerically. Consequently, a decisive role of noise in forming the diagnostic line was determined. Accordingly, this study develops a novel criterion for condition monitoring of rotating machinery.

  10. A novel method for condition monitoring of rotating machinery based on statistical linguistic analysis and weighted similarity measures

    Science.gov (United States)

    Lin, Jinshan; Dou, Chunhong

    2017-03-01

    Defective rotating machinery generally produces complex fluctuations due to non-stationary and nonlinear properties of dynamical systems. Consequently, dynamical structures of vibration data from rotating machinery are hard to disclose. As a result, condition monitoring of rotating machinery is fairly challenging. In this paper, statistical linguistic analysis (SLA), a novel tool for time series analysis, was introduced to analyze dynamical mechanisms hidden in vibration data of rotating machinery. SLA maps original vibration data from rotating machinery to a binary symbolic sequence by exploiting potential of increase and decreases of time intervals. Next, by sliding a window and identifying the elements in each window as a ;word;, a group of words is created. Then, by counting the occurrence of each word type, the binary symbolic sequence can be converted into a word frequency sequence. Next, a weighted similarity measure (WSM) defined in this paper serves to detect a change of running conditions of rotating machinery. As a result, this paper proposed a novel method for condition monitoring of rotating machinery based on SLA and WSM. Afterwards, the performance of the proposed method was validated using vibration data from both gearboxes and rolling bearings. Also, the proposed method was compared with conventional temporal statistical parameters, Approximate Entropy and Sample Entropy. The results indicate that the proposed method performs better than the other methods in condition monitoring of rotating machinery. Also, compared with either of Correlation Coefficients and Standardized Euclidean Distances, the WSM gives a somewhat better performance in reflecting a change of dynamical structures.

  11. Response of the integrals in the Tremaine-Weinberg method to multiple pattern speeds: a counter-rotating inner bar in NGC 2950?

    CERN Document Server

    Maciejewski, W

    2006-01-01

    When integrals in the standard Tremaine-Weinberg method are evaluated for the case of a realistic model of a doubly barred galaxy, their modifications introduced by the second rotating pattern are in accord with what can be derived from a simple extension of that method, based on separation of tracer's density. This extension yields a qualitative argument that discriminates between prograde and retrograde inner bars. However, the estimate of the value of inner bar's pattern speed requires further assumptions. When this extension of the Tremaine-Weinberg method is applied to the recent observation of the doubly barred galaxy NGC 2950, it indicates that the inner bar there is counter-rotating, possibly with the pattern speed of -140 +/- 50 km/s/arcsec. The occurrence of counter-rotating inner bars can constrain theories of galaxy formation.

  12. Role of Threaded Tool Pin Profile and Rotational Speed on Generation of Defect Free Friction Stir AA 2014 Aluminium Alloy Welds

    Directory of Open Access Journals (Sweden)

    Suresh D. Meshram

    2016-01-01

    Full Text Available Influence of threads on tool pin and rotational speeds on defect occurrence in friction stir welding (FSW of aluminum alloy AA 2014 T6 plates has been studied. The effect of FSW forces on the evolution of mechanistic defects, caused in turn through a variation in heat generation during the process has also been examined. In case of conical tool pin, relatively lower rotational speeds resulted in unbounded zones and micro defects while high speeds caused excessive flash, thereby resulting in surface defects and voids inside the weld. The FSW joints were defect-free at moderate speeds, hinting an optimum heat generation and flow. Reaction forces on the tool pin, in the welding direction, were correlated with the defect formation. Tools equipped with a threaded conical pin profile resulted in sound welds, irrespective of the tool rotational speeds in the entire range of 400 rpm - 2400 rpm. The threaded conical pin, with a relatively larger frictional area, may be contributing to higher levels of heat generation compared to a plain conical pin. Further, positive displacement of the hot plasticised material by the threads will carry away excess heat from the advancing-to-the-retracting side and simultaneously downwards, thus confining all heat within the weld zone.Defence Science Journal, Vol. 66, No. 1, January 2016, pp. 57-63, DOI: http://dx.doi.org/10.14429/dsj.66.8566

  13. Performance analysis of a novel planetary speed increaser used in single-rotor wind turbines with counter-rotating electric generator

    Science.gov (United States)

    Saulescu, R.; Neagoe, M.; Munteanu, O.; Cretescu, N.

    2016-08-01

    The paper presents a study on the kinematic and static performances of a new type of 1DOF (Degree Of Freedom) planetary speed increaser to be implemented in wind turbines, a transmission with three operating cases: a) one input and one output, b) one input and two outputs, in which the speed of the secondary output is equal to the input speed, and c) with one input and two outputs, where the secondary output speed is higher than the input speed. The proposed speed increaser contains two sun gears and a double satellite, allowing operation with an output connected to the fixed stator of a classic generator (case I) or with two counterrotating outputs that drive a counter-rotating generator (with a mobile stator). A new variant of planetary transmission capable of providing the speed increase of the generator stator and, thus, the increase of the relative speed between the generator rotor and stator is obtained by the parallel connection of the speed increaser with a planetary gear. The three conceptual variants of planetary transmission are analytically modelled and comparatively analysed based on a set of kinematic and static parameters. The proposed transmission has higher performances compared to the same transmission with one input and one output, the increase of the kinematic amplification ratio and efficiency being achieved simultaneously.

  14. Rotating Dual-Wire Beam Profile Monitor Optimized for Use in Merged-Beams Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Seely, D. G. [Albion College; Bruhns, H. [Columbia University; Savin, D. W. [Columbia University; Kvale, Thomas Jay [University of Toledo, Toledo, OH; Galutschek, Ernst [ORNL; Aliabadi, Habib [ORNL; Havener, Charles C [ORNL

    2008-01-01

    A rotating dual-wire beam proile monitor based upon a modified National Electrostatics Corporation Model BPM80 beam profile monitor is described. The device can measure beam profiles in two perpendicular directions (horizontal and vertical) in each of two pseudoplanes that are situated along the beam axis and are separated by a distance of 6.0 cm. The output signal from the device is analyzed in real time to yield horizontal and vertical beam profiles and to calculate the divergence of a particle beam that traverses the device. This set-up is well-suited for merged-beams experiments where one beam is tuned to saved profiles from a second beam in order to minimize the merge angle and beam divergences while maximizing the beam-beam overlaps.

  15. Rotating dual-wire beam profile monitor optimized for use in merged-beams experiments

    Energy Technology Data Exchange (ETDEWEB)

    Seely, D.G. [Department of Physics, Albion College, Albion, MI 49224-1831 (United States)], E-mail: dseely@albion.edu; Bruhns, H.; Savin, D.W. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027-6606 (United States); Kvale, T.J. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606-3390 (United States); Galutschek, E.; Aliabadi, H.; Havener, C.C. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States)

    2008-01-21

    A rotating dual-wire beam profile monitor based upon a National Electrostatics Corporation Model BPM80 beam profile monitor is described. The device can measure beam profiles in two perpendicular directions (horizontal and vertical) in each of two pseudoplanes that are situated along the beam axis and are separated by a distance of 5.4 cm. The output signal from the device is analyzed in real time to yield horizontal and vertical beam profiles and to calculate the divergence of a particle beam that traverses the device. This set-up is well-suited for merged-beams experiments where one beam is tuned to saved profiles from a second beam in order to minimize the merge angle and beam divergences while maximizing the beam-beam overlaps.

  16. Controlled hydrodynamic conditions on the formation of iron oxide nanostructures synthesized by electrochemical anodization: Effect of the electrode rotation speed

    Science.gov (United States)

    Lucas-Granados, Bianca; Sánchez-Tovar, Rita; Fernández-Domene, Ramón M.; García-Antón, Jose

    2017-01-01

    Iron oxide nanostructures are of particular interest because they can be used as photocatalysts in water splitting due to their advantageous properties. Electrochemical anodization is one of the best techniques to synthesize nanostructures directly on the metal substrate (direct back contact). In the present study, a novel methodology consisting of the anodization of iron under hydrodynamic conditions is carried out in order to obtain mainly hematite (α-Fe2O3) nanostructures to be used as photocatalysts for photoelectrochemical water splitting applications. Different rotation speeds were studied with the aim of evaluating the obtained nanostructures and determining the most attractive operational conditions. The synthesized nanostructures were characterized by means of Raman spectroscopy, Field Emission Scanning Electron Microscopy, photoelectrochemical water splitting, stability against photocorrosion tests, Mott-Schottky analysis, Electrochemical Impedance Spectroscopy (EIS) and band gap measurements. The results showed that the highest photocurrent densities for photoelectrochemical water splitting were achieved for the nanostructure synthesized at 1000 rpm which corresponds to a nanotubular structure reaching ∼0.130 mA cm-2 at 0.54 V (vs. Ag/AgCl). This is in agreement with the EIS measurements and Mott-Schottky analysis which showed the lowest resistances and the corresponding donor density values, respectively, for the nanostructure anodized at 1000 rpm.

  17. Speed of sound estimation with active PZT element for thermal monitoring during ablation therapy: feasibility study

    Science.gov (United States)

    Kim, Younsu; Guo, Xiaoyu; Cheng, Alexis; Boctor, Emad M.

    2016-04-01

    Controlling the thermal dose during ablation therapy is instrumental to successfully removing the tumor while preserving the surrounding healthy tissue. In the practical scenario, surgeons must be able to determine the ablation completeness in the tumor region. Various methods have been proposed to monitor it, one of which uses ultrasound since it is a common intraoperative imaging modality due to its non-invasive, cost-effective, and convenient natures. In our approach, we propose to use time of flight (ToF) information to estimate speed of sound changes. Accurate speed of sound estimation is crucial because it is directly correlated with temperature change and subsequent determination of ablation completeness. We divide the region of interest in a circular fashion with a variable radius from the ablator tip. We introduce the concept of effective speed of sound in each of the sub-regions. Our active PZT element control system facilitates this unique approach by allowing us to acquire one-way ToF information between the PZT element and each of the ultrasound elements. We performed a simulation and an experiment to verify feasibility of this method. The simulation result showed that we could compute the effective speed of sound within 0.02m/s error in our discrete model. We also perform a sensitivity analysis for this model. Most of the experimental results had less than 1% error. Simulation using a Gaussian continuous model with multiple PZT elements is also demonstrated. We simulate the effect of the element location one the optimization result.

  18. An Evaluation of Commercial Pedometers for Monitoring Slow Walking Speed Populations.

    Science.gov (United States)

    Beevi, Femina H A; Miranda, Jorge; Pedersen, Christian F; Wagner, Stefan

    2016-05-01

    Pedometers are considered desirable devices for monitoring physical activity. Two population groups of interest include patients having undergone surgery in the lower extremities or who are otherwise weakened through disease, medical treatment, or surgery procedures, as well as the slow walking senior population. For these population groups, pedometers must be able to perform reliably and accurately at slow walking speeds. The objectives of this study were to evaluate the step count accuracy of three commercially available pedometers, the Yamax (Tokyo, Japan) Digi-Walker(®) SW-200 (YM), the Omron (Kyoto, Japan) HJ-720 (OM), and the Fitbit (San Francisco, CA) Zip (FB), at slow walking speeds, specifically at 1, 2, and 3 km/h, and to raise awareness of the necessity of focusing research on step-counting devices and algorithms for slow walking populations. Fourteen participants 29.93 ±4.93 years of age were requested to walk on a treadmill at the three specified speeds, in four trials of 100 steps each. The devices were worn by the participants on the waist belt. The pedometer counts were recorded, and the error percentage was calculated. The error rate of all three evaluated pedometers decreased with the increase of speed: at 1 km/h the error rates varied from 87.11% (YM) to 95.98% (FB), at 2 km/h the error rates varied from 17.27% (FB) to 46.46% (YM), and at 3 km/h the error rates varied from 22.46% (YM) to a slight overcount of 0.70% (FB). It was observed that all the evaluated devices have high error rates at 1 km/h and mixed error rates at 2 km/h, and at 3 km/h the error rates are the smallest of the three assessed speeds, with the OM and the FB having a slight overcount. These results show that research on pedometers' software and hardware should focus more on accurate step detection at slow walking speeds.

  19. 风机转动速度调节的PID优化算法研究%Research on PID Optimization Algorithm for Rotating Speed Regulation of Wind Turbine

    Institute of Scientific and Technical Information of China (English)

    李家伟

    2015-01-01

    With control optimizing of the rotational speed of the wind turbine, improve the output power and the power trans-mission efficiency of the wind turbine, the interference of magnetic loss coupling by the wind turbine rotor blade in the con-trol, it is difficult to achieve effective speed regulation, The algorithm has the defects of nonlinear distortion. A wind turbine of PID based on optimal control of rotating speed adjustment optimization, analysis of rotating speed adjusting parameter model of wind turbine, the wind turbine rotor blade speed adjustment control optimization objective function, the design of three layers PID neural network, the PID variable structure control, wind turbine speed shaft connected with the rotor axis the gear box, the aerodynamic excitation brake operation, speed regulation, effectively restrain the interference of wind tur-bine rotor blade control strong coupling magnetic loss, improve the speed of rotation to adjust the output control perfor-mance of wind turbine. The simulation results show that, the method can effectively realize the wind turbine speed control, it can improve the wind turbine efficiency and output gain.%通过对风机转动速度的优化控制调节,提高风机的输出功率和电能传输效率,风机转子叶片控制中受到强耦合的磁损耗的干扰,难以实现有效的转速调节,提出一种基于PID优化控制的风机转动速度调节优化算法,分析风机转动速度调节控制参数模型,构建风机转子叶片速度调节的优化控制目标函数,设计三层前向PID神经网络,通过PID变结构控制,风机的低速轴将转子轴心与齿轮箱连接,激发空气动力闸的运行,进行转速调节,有效地抑制了风机转子叶片控制中强耦合磁损耗的干扰,提高了风机转动速度调节输出控制性能.仿真结果表明,采用该方法能有效实现风机转速调节控制,提高风机运行效率和输出增益.

  20. Evaluating the Acoustic Effect of Over-the-Rotor Foam-Metal Liner Installed on a Low Speed Fan Using Virtual Rotating Microphone Imaging

    Science.gov (United States)

    Sutliff, Daniel L.; Dougherty, Robert P.; Walker, Bruce E.

    2010-01-01

    An in-duct beamforming technique for imaging rotating broadband fan sources has been used to evaluate the acoustic characteristics of a Foam-Metal Liner installed over-the-rotor of a low-speed fan. The NASA Glenn Research Center s Advanced Noise Control Fan was used as a test bed. A duct wall-mounted phased array consisting of several rings of microphones was employed. The data are mathematically resampled in the fan rotating reference frame and subsequently used in a conventional beamforming technique. The steering vectors for the beamforming technique are derived from annular duct modes, so that effects of reflections from the duct walls are reduced.

  1. Design of rotation portable speed measurement and display system%便携式转速测量及显示系统设计

    Institute of Scientific and Technical Information of China (English)

    岳晗; 裴东兴; 张瑜

    2012-01-01

    为方便、精确测量精密离心机的转速,采用非接触式全数字化的测量方法,设计了便携式的转速测量及显示装置。该系统主要由STC系列单片机、光电转换传感器以及液晶显示屏3部分组成。光电转换传感器将光信号转换成电脉冲信号,此脉冲信号适应性强,能够与单片机直接联接。单片机接收此脉冲信号并记录脉冲个数及所用时间,对数据进行处理得到离心机的转速。实验验证了该系统使用简单、精确度高、在便携化的前提下实现了转速精确的测量及显示功能,给转速的测量带来了极大的方便。%In order to meet the needs of measuring precision centrifuge's rotation speed in convenient and accurate, this paper designed portable rotation speed measurement and display device, adopted the non-contact and full digital measurement method. This system is mainly composed of the following three parts: STC series microcontroller, photoelectric speed sensor and liquid crystal display(LCD). Photoelectric speed sensor converts the optical signal into an electrical pulse signal, this pulse have strong adaptation that can directly connected with microcontroller, microcontroller receives this pulse signal and recording the time it use and the number of pulse signal. By measuring the rotation speed of precision centrifuge verified this system is simple to use, has high precision and under the promise of portable realized the function of accurate measurement and display rotation speed, this system has brought great convenience for measuring rotation speeds

  2. Speed of sound estimation for thermal monitoring using an active ultrasound element during liver ablation therapy (Conference Presentation)

    Science.gov (United States)

    Kim, Younsu; Audigier, Chloé; Dillow, Austin; Cheng, Alexis; Boctor, Emad M.

    2017-03-01

    Thermal monitoring for ablation therapy has high demands for preserving healthy tissues while removing malignant ones completely. Various methods have been investigated. However, exposure to radiation, cost-effectiveness, and inconvenience hinder the use of X-ray or MRI methods. Due to the non-invasiveness and real-time capabilities of ultrasound, it is widely used in intraoperative procedures. Ultrasound thermal monitoring methods have been developed for affordable monitoring in real-time. We propose a new method for thermal monitoring using an ultrasound element. By inserting a Lead-zirconate-titanate (PZT) element to generate the ultrasound signal in the liver tissues, the single travel time of flight is recorded from the PZT element to the ultrasound transducer. We detect the speed of sound change caused by the increase in temperature during ablation therapy. We performed an ex vivo experiment with liver tissues to verify the feasibility of our speed of sound estimation technique. The time of flight information is used in an optimization method to recover the speed of sound maps during the ablation, which are then converted into temperature maps. The result shows that the trend of temperature changes matches with the temperature measured at a single point. The estimation error can be decreased by using a proper curve linking the speed of sound to the temperature. The average error over time was less than 3 degrees Celsius for a bovine liver. The speed of sound estimation using a single PZT element can be used for thermal monitoring.

  3. A Character Segmentation Proposal for High-Speed Visual Monitoring of Expiration Codes on Beverage Cans

    Directory of Open Access Journals (Sweden)

    José C. Rodríguez-Rodríguez

    2016-04-01

    Full Text Available Expiration date labels are ubiquitous in the food industry. With the passage of time, almost any food becomes unhealthy, even when well preserved. The expiration date is estimated based on the type and manufacture/packaging time of that particular food unit. This date is then printed on the container so it is available to the end user at the time of consumption. MONICOD (MONItoring of CODes; an industrial validator of expiration codes; allows the expiration code printed on a drink can to be read. This verification occurs immediately after printing. MONICOD faces difficulties due to the high printing rate (35 cans per second and problematic lighting caused by the metallic surface on which the code is printed. This article describes a solution that allows MONICOD to extract shapes and presents quantitative results for the speed and quality.

  4. A Character Segmentation Proposal for High-Speed Visual Monitoring of Expiration Codes on Beverage Cans.

    Science.gov (United States)

    Rodríguez-Rodríguez, José C; Quesada-Arencibia, Alexis; Moreno-Díaz, Roberto; García, Carmelo R

    2016-04-13

    Expiration date labels are ubiquitous in the food industry. With the passage of time, almost any food becomes unhealthy, even when well preserved. The expiration date is estimated based on the type and manufacture/packaging time of that particular food unit. This date is then printed on the container so it is available to the end user at the time of consumption. MONICOD (MONItoring of CODes); an industrial validator of expiration codes; allows the expiration code printed on a drink can to be read. This verification occurs immediately after printing. MONICOD faces difficulties due to the high printing rate (35 cans per second) and problematic lighting caused by the metallic surface on which the code is printed. This article describes a solution that allows MONICOD to extract shapes and presents quantitative results for the speed and quality.

  5. Complete Model-Based Equivalence Class Testing for the ETCS Ceiling Speed Monitor

    DEFF Research Database (Denmark)

    Braunstein, Cécile; Haxthausen, Anne Elisabeth; Huang, Wen-ling

    2014-01-01

    In this paper we present a new test model written in SysML and an associated blackbox test suite for the Ceiling Speed Monitor (CSM) of the European Train Control System (ETCS). The model is publicly available and intended to serve as a novel benchmark for investigating new testing theories......_nite cardinality of the input domains { is capable to produce _nite test suites that are complete (i.e. sound and exhaustive) for a given fault model. In this paper, an overview of the model and the equivalence class testing strategy is given, and tool-based evaluation results are presented. For the technical...... and comparing the capabilities of modelbased test automation tools. The CSM application inputs velocity values from a domain which could not be completely enumerated for test purposes with reasonable e_ort. We therefore apply a novel method for equivalence class testing that { despite the conceptually in...

  6. Near-Infrared Imaging Using a High-Speed Monitoring Near Infrared Hyperspectral Camera (Compovision)

    Institute of Scientific and Technical Information of China (English)

    Daitaro Ishikawa; Asako Motomura; Yoko Igarashi; Yukihiro Ozaki

    2015-01-01

    This review paper reports near‐infrared (NIR) imaging studies using a newly‐developed NIR camer‐a ,Compovision .Compovision can measure a significantly wide area of 150 mm × 250 mm at high speed of be‐tween 2 and 5 s .It enables a wide spectral region measurement in the 1 000~2 350 nm range at 6 nm inter‐vals .We investigated the potential of Compovision in the applications to industrial problems such as the evalu‐ation of pharmaceutical tablets and polymers .Our studies have demonstrated that NIR imaging based on Com‐povision can solve several issues such as long acquisition times and relatively low sensitivity of detection .NIR imaging with Compovision is strongly expected to be applied not only to pharmaceutical tablet monitoring and polymer characterization but also to various applications such as those to food products ,biomedical substances and organic and inorganic materials .

  7. LMD method and multi-class RWSVM of fault diagnosis for rotating machinery using condition monitoring information.

    Science.gov (United States)

    Liu, Zhiwen; Chen, Xuefeng; He, Zhengjia; Shen, Zhongjie

    2013-07-05

    Timely and accurate condition monitoring and fault diagnosis of rotating machinery are very important to maintain a high degree of availability, reliability and operational safety. This paper presents a novel intelligent method based on local mean decomposition (LMD) and multi-class reproducing wavelet support vector machines (RWSVM), which is applied to diagnose rotating machinery faults. First, the sensor-based vibration signals measured from the rotating machinery are preprocessed by the LMD method and product functions (PFs) are produced. Second, statistic features are extracted to acquire more fault characteristic information from the sensitive PF. Finally, these features are fed into a multi-class RWSVM to identify the rotating machinery health conditions. The experimental results validate the effectiveness of the proposed RWSVM method in identifying rotating machinery fault patterns accurately and effectively and its superiority over that based on the general SVM.

  8. LMD Method and Multi-Class RWSVM of Fault Diagnosis for Rotating Machinery Using Condition Monitoring Information

    Directory of Open Access Journals (Sweden)

    Zhongjie Shen

    2013-07-01

    Full Text Available Timely and accurate condition monitoring and fault diagnosis of rotating machinery are very important to maintain a high degree of availability, reliability and operational safety. This paper presents a novel intelligent method based on local mean decomposition (LMD and multi-class reproducing wavelet support vector machines (RWSVM, which is applied to diagnose rotating machinery faults. First, the sensor-based vibration signals measured from the rotating machinery are preprocessed by the LMD method and product functions (PFs are produced. Second, statistic features are extracted to acquire more fault characteristic information from the sensitive PF. Finally, these features are fed into a multi-class RWSVM to identify the rotating machinery health conditions. The experimental results validate the effectiveness of the proposed RWSVM method in identifying rotating machinery fault patterns accurately and effectively and its superiority over that based on the general SVM.

  9. A combined method for high-speed rail seismic monitoring and early warning

    Directory of Open Access Journals (Sweden)

    Zhigao Chen

    2017-09-01

    Full Text Available The ground motion characteristics include the strength, frequency spectrum and duration time. In China, the PGA (peak ground acceleration is commonly used in determination of whether an earthquake warning is necessary when the high-speed train is on the rail. This method has not given an earthquake early warning time, and it only considers the strength factor of an earthquake, so the system may release an alarm for the near and small earthquakes which are no destructive. The new alarm method reconciles the timeliness and stability. It issues a P wave warning when the system receives seismic wave first, which will make the train to decelerate. Then, the system will confirm whether the P wave alarm is correct using the joint alarm result of CAV (cumulative absolute velocity and PGA, and then take measures according to the result. The new method eliminates the interference from the near and small earthquakes, as well as the large and far earthquakes, and ensures the safety of the train when it is subjected to earthquakes. In this paper, we use seismic data to simulate the combined alarm of CAV and PGA, and then obtain the cumulative time of CAV and the time interval between CAV and PGA. Finally, we compare the new method with the double-station, earthquake monitoring alarm method which is currently used on China's high-speed rail, and find the new alarm method is better in the aspect of alarm timeliness.

  10. First test results of a high-speed beam conditions monitor for the ATLAS experiment

    CERN Document Server

    Pernegger, Heinz

    2004-01-01

    The paper presents the design and first test results of the high- speed beam conditions monitor (BCM) for the ATLAS experiment at the large hadron collider (LHC). The goal of the BCM is to monitor instantaneous rates of collision and background and detect signs of beam instabilities. The detector is based on polycrystalline chemical-vapor-deposition (pCVD) diamond as active sensor material. We have chosen this detector material for its proven radiation hardness and fast signal properties. For the readout of the diamonds we developed front-end readout electronics based on high-bandwidth RF amplifiers. The signal response of the amplifier has been optimized for the ionization current signal of pCVD diamond in order to achieve a signal risetime of

  11. Dynamic characterization, monitoring and control of rotating flexible beam-mass structures via piezo-embedded techniques

    Science.gov (United States)

    Lai, Steven H.-Y.

    1992-01-01

    A variational principle and a finite element discretization technique were used to derive the dynamic equations for a high speed rotating flexible beam-mass system embedded with piezo-electric materials. The dynamic equation thus obtained allows the development of finite element models which accommodate both the original structural element and the piezoelectric element. The solutions of finite element models provide system dynamics needed to design a sensing system. The characterization of gyroscopic effect and damping capacity of smart rotating devices are addressed. Several simulation examples are presented to validate the analytical solution.

  12. Optimal body size with respect to maximal speed for the yellow-spotted monitor lizard (Varanus panoptes; Varanidae).

    Science.gov (United States)

    Clemente, Christofer J; Withers, Philip C; Thompson, Graham

    2012-01-01

    Studies of locomotor performance often link variation in morphology with ecology. While maximum sprint speed is a commonly used performance variable, the absolute limits for this performance trait are not completely understood. Absolute maximal speed has often been shown to increase linearly with body size, but several comparative studies covering a large range of body sizes suggest that maximal speed does not increase indefinitely with body mass but rather reaches an optimum after which speed declines. Because of the comparative nature of these studies, it is difficult to determine whether this decrease is due to biomechanical constraints on maximal speed or is a consequence of phylogenetic inertia or perhaps relaxed selection for lower maximal speed at large body size. To explore this issue, we have examined intraspecific variations in morphology, maximal sprint speed, and kinematics for the yellow-spotted monitor lizard Varanus panoptes, which varied in body mass from 0.09 to 5.75 kg. We show a curvilinear relationship between body size and absolute maximal sprint speed with an optimal body mass with respect to speed of 1.245 kg. This excludes the phylogenetic inertia hypothesis, because this effect should be absent intraspecifically, while supporting the biomechanical constraints hypothesis. The relaxed selection hypothesis cannot be excluded if there is a size-based behavioral shift intraspecifically, but the biomechanical constraints hypothesis is better supported from kinematic analyses. Kinematic measurements of hind limb movement suggest that the distance moved by the body during the stance phase may limit maximum speed. This limit is thought to be imposed by a decreased ability of the bones and muscles to support body mass for larger lizards.

  13. Proposal for verifying Wigner's rotation with massive spin-$1/2$ particles at non-relativistic speeds

    OpenAIRE

    Palge, Veiko; Dunningham, Jacob; Hasegawa, Yuji

    2016-01-01

    In quantum physics Wigner's rotation is commonly regarded as confirmed by the Thomas precession in a hydrogen like atom. In this paper we show that a direct experimental verification of Wigner's rotation is in principle accessible in the regime of non-relativistic velocities at $2 \\cdot 10^3\\,$m/s and propose an experiment using thermal neutrons. The experiment can be carried out in a laboratory and it provides a test of relativity in the quantum domain.

  14. Rotation speed measurement for turbine governor: torsion filtering by using Kalman filter; Mesure de la vitesse de rotation d`un groupe turboalternateur: application de la theorie de kalman au probleme du filtrage des oscillations torsionnelles

    Energy Technology Data Exchange (ETDEWEB)

    Houry, M.P.; Bourles, H.

    1996-12-31

    The rotation speed of a turbogenerator is disturbed by its shaft torsion. Obtaining a filtered measure of this speed is a problem of a great practical importance for turbine governor. A good filtering of this speed must meet two requirements: it must cut frequencies of the shaft torsion oscillation and it must not reduce or delay the signal in the pass-band, i.e. at lower frequencies. At Electricite de France, the speed measure is used to set in motion the fast valving system as quickly as possible, after a short circuit close to the unit or rather an islanding. It is difficult to satisfy these two requirements by using conventional filtering methods. The standard solution consists in a first order filter: at Electricite de France, its time constant is equal to 80 ms. We have decided to improve this filtering by designing a new filter which cuts the frequencies of the shaft torsion oscillation without reducing the bandwidth to the speed measure. If one uses conventional methods to obtain a band stop filter, it is easy to obtain the desired magnitude but not a phase near zero in the whole pass-band. Therefore, we have chosen to design the filter by using Kalman`a theory. The measurement noise is modeled as a colored one, generated by a very lightly damped system driven by a while noise. The resulting Kalman filter is an effective band stop filter, whose phase nicely remains near zero in the whole pass-band. The digital simulations we made and the tests we carried out with the Electricite de France Micro Network laboratory show the advantages of the rotation speed filter we designed using Kalman`s theory. With the proposed filter, the speed measure filtering is better in terms of reduction and phase shift. the result is that there are less untimely solicitations of the fast valving system. Consequently, this device improves the power systems stability by minimizing the risks of deep perturbations due to a temporary lack of generation and the risks of under-speed loss

  15. Nanoparticle induced cell magneto-rotation: monitoring morphology, stress and drug sensitivity of a suspended single cancer cell.

    Directory of Open Access Journals (Sweden)

    Remy Elbez

    Full Text Available Single cell analysis has allowed critical discoveries in drug testing, immunobiology and stem cell research. In addition, a change from two to three dimensional growth conditions radically affects cell behavior. This already resulted in new observations on gene expression and communication networks and in better predictions of cell responses to their environment. However, it is still difficult to study the size and shape of single cells that are freely suspended, where morphological changes are highly significant. Described here is a new method for quantitative real time monitoring of cell size and morphology, on single live suspended cancer cells, unconfined in three dimensions. The precision is comparable to that of the best optical microscopes, but, in contrast, there is no need for confining the cell to the imaging plane. The here first introduced cell magnetorotation (CM method is made possible by nanoparticle induced cell magnetization. By using a rotating magnetic field, the magnetically labeled cell is actively rotated, and the rotational period is measured in real-time. A change in morphology induces a change in the rotational period of the suspended cell (e.g. when the cell gets bigger it rotates slower. The ability to monitor, in real time, cell swelling or death, at the single cell level, is demonstrated. This method could thus be used for multiplexed real time single cell morphology analysis, with implications for drug testing, drug discovery, genomics and three-dimensional culturing.

  16. Study and modeling of changes in volumetric efficiency of helix conveyors at different rotational speeds and inclination angels by ANFIS and statistical methods

    Directory of Open Access Journals (Sweden)

    A Zareei

    2017-05-01

    Full Text Available Introduction Spiral conveyors effectively carry solid masses as free or partly free flow of materials. They create good throughput and they are the perfect solution to solve the problems of transport, due to their simple structure, high efficiency and low maintenance costs. This study aims to investigate the performance characteristics of conveyors as function of auger diameter, rotational speed and handling inclination angle. The performance characteristic was investigated according to volumetric efficiency. In another words, the purpose of this study was obtaining a suitable model for volumetric efficiency changes of steep auger to transfer agricultural products. Three different diameters of auger, five levels of rotational speed and three slope angles were used to investigate the effects of changes in these parameters on volumetric efficiency of auger. The used method is novel in this area and the results show that performance by ANFIS models is much better than common statistical models. Materials and Methods The experiments were conducted in Department of Mechanical Engineering of Agricultural Machinery in Urmia University. In this study, SAYOS cultivar of wheat was used. This cultivar of wheat had hard seeds and the humidity was 12% (based on wet. Before testing, all foreign material was separated from the wheat such as stone, dust, plant residues and green seeds. Bulk density of wheat was 790 kg m-3. The auger shaft of the spiral conveyor was received its rotational force through belt and electric motor and its rotation leading to transfer the product to the output. In this study, three conveyors at diameters of 13, 17.5, and 22.5 cm, five levels of rotational speed at 100, 200, 300, 400, and 500 rpm and three handling angles of 10, 20, and 30º were tested. Adaptive Nero-fuzzy inference system (ANFIS is the combination of fuzzy systems and artificial neural network, so it has both benefits. This system is useful to solve the complex non

  17. High-resolution Calculation of the Solar Global Convection with the Reduced Speed of Sound Technique. II. Near Surface Shear Layer with the Rotation

    Science.gov (United States)

    Hotta, H.; Rempel, M.; Yokoyama, T.

    2015-01-01

    We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from helioseismology. Using the reduced speed of sound technique, we can extend our global convection simulation to 0.99 R ⊙ and include, near the top of our domain, small-scale convection with short timescales that is only weakly influenced by rotation. We find the formation of an NSSL preferentially in high latitudes in the depth range of r = 0.95-0.975 R ⊙. The maintenance mechanisms are summarized as follows. Convection under the weak influence of rotation leads to Reynolds stresses that transport angular momentum radially inward in all latitudes. This leads to the formation of a strong poleward-directed meridional flow and an NSSL, which is balanced in the meridional plane by forces resulting from the correlation of turbulent velocities. The origin of the required correlations depends to some degree on latitude. In high latitudes, a positive correlation is induced in the NSSL by the poleward meridional flow whose amplitude increases with the radius, while a negative correlation is generated by the Coriolis force in bulk of the convection zone. In low latitudes, a positive correlation results from rotationally aligned convection cells ("banana cells"). The force caused by these Reynolds stresses is in balance with the Coriolis force in the NSSL.

  18. [Research of working condition monitoring and analyzing system for rotating anode X-ray tube based on the vibration measurement].

    Science.gov (United States)

    Wu, Hao; Wang, Weidong; Yan, Yong; Zhang, Shuai; Zu, Hefei; Chen, Weibin

    2011-01-01

    A non-invasive detecting and analyzing method which used to monitor the working condition of rotating anode X-ray was proposed. Based on the NI development environment, accelerometer, 24-bit high resolution data acquisition card and personal computer were connected to construct the system for collecting the vibration signal of X-ray tube. Results demonstrate that the system could acquire and store the vibration data of X-ray tube quickly and efficiently. The characteristics of vibration, were extracted and processed, which proposed a new approach to detect the malfunction of rotating anode X-ray early and effectively.

  19. GroundBIRD: Observing Cosmic Microwave Polarization at Large Angular Scale with Kinetic Inductance Detectors and High-Speed Rotating Telescope

    Science.gov (United States)

    Oguri, S.; Choi, J.; Damayanthi, T.; Hattori, M.; Hazumi, M.; Ishitsuka, H.; Karatsu, K.; Mima, S.; Minowa, M.; Nagasaki, T.; Otani, C.; Sekimoto, Y.; Tajima, O.; Tomita, N.; Yoshida, M.; Won, E.

    2016-08-01

    Cosmic microwave background (CMB) is an important source of information about the origin of our universe. In particular, odd-parity large angular scale patterns in the CMB polarization, the primordial B-modes, are strong evidence for an inflationary universe, related to the accelerating expansion of the metric. We are developing a unique telescope, GroundBIRD, to take CMB polarization measurements. The telescope combines novel techniques: high-speed rotation scanning, cold optics, and microwave kinetic inductance detectors (MKIDs). We evaluated the response of MKIDs on the rotation stage. Method of shielding from the geo-magnetic field is established. We have also developed a receiver cryostat. We are able to maintain a sufficient cold status for observations on the optical configuration. We plan to start commissioning the system by observing CMB in Japan in 2015-2016. We will then deploy GroundBIRD in the Canary Islands for further scientific observations.

  20. The method of the gas-dynamic centrifugal compressor stage characteristics recalculation for variable rotor rotational speeds and the rotation angle of inlet guide vanes blades if the kinematic and dynamic similitude conditions are not met

    Science.gov (United States)

    Vanyashov, A. D.; Karabanova, V. V.

    2017-08-01

    A mathematical description of the method for obtaining gas-dynamic characteristics of a centrifugal compressor stage is proposed, taking into account the control action by varying the rotor speed and the angle of rotation of the guide vanes relative to the "basic" characteristic, if the kinematic and dynamic similitude conditions are not met. The formulas of the correction terms for the non-dimensional coefficients of specific work, consumption and efficiency are obtained. A comparative analysis of the calculated gas-dynamic characteristics of a high-pressure centrifugal stage with experimental data is performed.

  1. Edge-filter technique and dominant frequency analysis for high-speed railway monitoring with fiber Bragg gratings

    Science.gov (United States)

    Kouroussis, Georges; Kinet, Damien; Mendoza, Edgar; Dupuy, Julien; Moeyaert, Véronique; Caucheteur, Christophe

    2016-07-01

    Structural health and operation monitoring are of growing interest in the development of railway networks. Conventional systems of infrastructure monitoring already exist (e.g. axle counters, track circuits) but present some drawbacks. Alternative solutions are therefore studied and developed. In this field, optical fiber sensors, and more particularly fiber Bragg grating (FBG) sensors, are particularly relevant due to their immunity to electromagnetic fields and simple wavelength-division-multiplexing capability. Field trials conducted up to now have demonstrated that FBG sensors provide useful information about train composition, positioning, speed, acceleration and weigh-in-motion estimations. Nevertheless, for practical deployment, cost-effectiveness should be ensured, specifically at the interrogator side that has also to be fast (>1 kHz repetition rate), accurate (∼1 pm wavelength shift) and reliable. To reach this objective, we propose in this paper to associate a low cost and high-speed interrogator coupled with an adequate signal-processing algorithm to dynamically monitor cascaded wavelength-multiplexed FBGs and to accurately capture the parameters of interest for railway traffic monitoring. This method has been field-tested with a Redondo Optics Inc. interrogator based on the well-known edge-filter demodulation technique. To determine the train speed from the raw data, a dominant frequency analysis has been implemented. Using this original method, we show that we can retrieve the speed of the trains, even when the time history strain signature is strongly affected by the measurement noise. The results are assessed by complimentary data obtained from a spectrometer-based FBG interrogator.

  2. A comparison of aircraft tire skid with initial wheel\\ud rotational speed using ANSYS transient simulation

    OpenAIRE

    Alroqi, Abdurrhman A; Wang, Weiji

    2016-01-01

    Based on heavy aircraft main landing gear tires touchdown skidding process, patents have been registered since the 1940s to improve tire safety, decrease the substantial wear and smoke that results from every landing by spinning the rear wheels before touchdown. A single wheel has been modeled as a mass-spring-damper system using ANSYS mechanical transient simulation to analyze static and pre-rotating wheels behavior during a short period between touchdown and skidding, to spin-up to reach th...

  3. High-resolution calculation of the solar global convection with the reduced speed of sound technique: II. Near surface shear layer with the rotation

    CERN Document Server

    Hotta, H; Yokoyama, T

    2014-01-01

    We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from helioseismology. Using the reduced speed of sound technique we can extend our global convection simulation to $0.99\\,R_{\\odot}$ and include near the top of our domain small-scale convection with short time scales that is only weakly influenced by rotation. We find the formation of a NSSL preferentially in high latitudes in the depth range $r=0.95-0.975R_\\odot$. The maintenance mechanisms are summarized as follows. Convection under weak influence of rotation leads to Reynolds stresses that transport angular momentum radially inward in all latitudes. This leads to the formation of a strong poleward directed meridional flow and a NSSL, which is balanced in the meridional plane by forces resulting from the $\\langle v'_r v'_\\theta\\rangle$ correlation of turbulent velocities. The orig...

  4. Advanced Modular, Multi-Channel, High Speed Fiber Optic Sensing System for Acoustic Emissions Monitoring Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Intelligent Fiber Optic Systems Corporation (IFOS) proposes to prove the feasibility of innovations based on ultra-light-weight, ultra-high-speed, multi-channel,...

  5. A non-contacting approach for full field dynamic strain monitoring of rotating structures using the photogrammetry, finite element, and modal expansion techniques

    Science.gov (United States)

    Baqersad, Javad

    Health monitoring of rotating structures such as wind turbines and helicopter rotors is generally performed using conventional sensors that provide a limited set of data at discrete locations near or on the hub. These sensors usually provide no data on the blades or interior locations where failures may occur. Within this work, an unique expansion algorithm was extended and combined with finite element (FE) modeling and an optical measurement technique to identify the dynamic strain in rotating structures. The merit of the approach is shown by using the approach to predict the dynamic strain on a small non-rotating and rotating wind turbine. A three-bladed wind turbine having 2.3-meter long blades was placed in a semi-built-in boundary condition using a hub, a machining chuck, and a steel block. A finite element model of the three wind turbine blades assembled to the hub was created and used to extract resonant frequencies and mode shapes. The FE model was validated and updated using experimental modal tests. For the non-rotating optical test, the turbine was excited using a sinusoidal excitation, a pluck test, arbitrary impacts on three blades, and random force excitations with a mechanical shaker. The response of the structure to the excitations was measured using three-dimensional point tracking. A pair of high-speed cameras was used to measure the displacement of optical targets on the structure when the blades were vibrating. The measured displacements at discrete locations were expanded and applied to the finite element model of the structure to extract the full-field dynamic strain. The results of the work show an excellent correlation between the strain predicted using the proposed approach and the strain measured with strain-gages for all of the three loading conditions. Similar to the non-rotating case, optical measurements were also preformed on a rotating wind turbine. The point tracking technique measured both rigid body displacement and flexible

  6. HIGH-RESOLUTION CALCULATION OF THE SOLAR GLOBAL CONVECTION WITH THE REDUCED SPEED OF SOUND TECHNIQUE. II. NEAR SURFACE SHEAR LAYER WITH THE ROTATION

    Energy Technology Data Exchange (ETDEWEB)

    Hotta, H.; Rempel, M. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO (United States); Yokoyama, T., E-mail: hotta@ucar.edu [Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2015-01-01

    We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from helioseismology. Using the reduced speed of sound technique, we can extend our global convection simulation to 0.99 R {sub ☉} and include, near the top of our domain, small-scale convection with short timescales that is only weakly influenced by rotation. We find the formation of an NSSL preferentially in high latitudes in the depth range of r = 0.95-0.975 R {sub ☉}. The maintenance mechanisms are summarized as follows. Convection under the weak influence of rotation leads to Reynolds stresses that transport angular momentum radially inward in all latitudes. This leads to the formation of a strong poleward-directed meridional flow and an NSSL, which is balanced in the meridional plane by forces resulting from the 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 correlation of turbulent velocities. The origin of the required correlations depends to some degree on latitude. In high latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 is induced in the NSSL by the poleward meridional flow whose amplitude increases with the radius, while a negative correlation is generated by the Coriolis force in bulk of the convection zone. In low latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 results from rotationally aligned convection cells ({sup b}anana cells{sup )}. The force caused by these Reynolds stresses is in balance with the Coriolis force in the NSSL.

  7. Thromboelastography (TEG) or rotational thromboelastometry (ROTEM) to monitor haemostatic treatment in bleeding patients

    DEFF Research Database (Denmark)

    Wikkelsø, A; Wetterslev, J; Møller, A M

    2017-01-01

    of publication status, publication date, blinding status, outcomes published or language from date of inception to 5 January 2016 in six bibliographic databases. We included 17 trials (1493 participants), most involving cardiac surgery. Thromboelastography or rotational thromboelastometry seemed to reduce...

  8. ARBRE monitoring - ecology of short rotation coppice. Four year study involving wildlife monitoring of commercial SCR plantations planted on arable land and arable control plots

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, M.D.; Bishop, J.D.; McKay, H.V.; Sage, R.B.

    2004-07-01

    This report summarises the findings of the UK Department of Trade and Industry (DTI) funded project monitoring wildlife within and around a number of commercially managed Short Rotation Coppice (SRC) plantations aimed at using the information gathered to assess the ecological impact of SRC plantations on the wildlife in the area. The background to the study is traced, and details are given of the monitoring programme examining the distribution of flora and fauna within the plantations, and the monitoring of birds, plants, insects and butterflies. The greater diversity of wildlife and plants in the SRC plots, the higher densities of birds, and the increasing number of butterfly species are discussed along with the increased mean number of invertebrate orders with subsequent growth of willow coppices, and the habitats at the edges of the plots and at headlands designed for access to machinery within the plots.

  9. Rotation speed measurement for turbine governor: torsion filtering by using Kalman filter; Mesure de la vitesse de rotation d`un groupe turboalternateur: application de la theorie de Kalman au filtrage des oscillations torsionnelles

    Energy Technology Data Exchange (ETDEWEB)

    Houry, M.P.; Bourles, H.

    1995-11-01

    The rotation speed of a turbogenerator is disturbed by its shaft torsion. Obtaining a filtered measure of this sped a problem of a great practical importance for turbine governor. A good filtering of this speed must meet two requirements: it must cut frequencies of the shaft torsion oscillation and it must not reduce or delay the signal in the pass-band. i.e. at lower frequencies. At Electricite de France, the speed measure is used to set in motion the fast valving system as quickly as possible, after a short circuit close to the unit (to contribute to the stability) or after an islanding (to quickly reach a balance with the house load). It is difficult to satisfy these two requirements by using conventional filtering methods. The standard solution consists in a first order filter: at Electricite de France, its time constant is equal to 80 ms; We have decided to improve this filtering by designing a new filter which cuts the frequencies of the shaft torsion oscillation without reducing the bandwidth of the speed measure. If one uses conventional methods to obtain a band-stop filter (for instance a Butterworth, a Chebyshev or an elliptic band-stop filter),it is easy to obtain the desired magnitude but not a phase near zero in the whole pass-band. Therefore, we have chosen to design the filter by using Kalman`s theory. The measurement noise is modeled as a colored one, generated by a very lightly damped system driven by a white noise. The resulting Kalman filter is an effective band-stop filter, whose phase nicely remains near zero in the whole pass-band. (authors). 13 refs., 12 figs.

  10. 基于连续波雷达微多普勒效应的弹丸转速测试方法%Testing Method of Projectile Rotating Speed Based on Micro-Doppler Effect of CW Radars

    Institute of Scientific and Technical Information of China (English)

    张万君; 吴晓颖; 冷雪冰; 李文珍; 纪兵

    2012-01-01

    Aiming at the limitation of testing methods for projectile rotating speed, a new testing method of projectile rotating speed is put forward. The radar echo micro-Doppler modulated mathematic model caused by projectile rotation is built by using micro-Doppler effect resulted from CW radar detection of projectile rotations, the internal relationship between micro-Doppler frequency and projectile rotating speed is derived, and testing methods of micro-Doppler data for projectile rotating speed is provided. The projectile rotating speed is extracted by micro-motion identification and digital demodulation of projectile rotation, and the good testing effect is validated by shooting range test.%针对目前弹丸转速测试方法的局限,提出了一种新的弹丸转速测试方法,利用连续波雷达探测弹丸旋转产生的微多普勒效应,建立了弹丸旋转运动引起的雷达回波微多普勒调制数学模型,推导了微多普勒频率与弹丸转速的解析关系,给出了弹丸转速微多普勒数据的实测方案,并通过弹丸旋转微动辨识与数字解调技术,提取出弹丸转速,经靶场试验验证,测试效果良好。

  11. Analysis of the monitoring data of geomagnetic storm interference in the electrification system of a high-speed railway

    Science.gov (United States)

    Liu, Lianguang; Ge, Xiaoning; Zong, Wei; Zhou, You; Liu, Mingguang

    2016-10-01

    To study the impact of geomagnetic storm on the equipment of traction electrification system in the high-speed railway, geomagnetically induced current (GIC) monitoring devices were installed in the Hebi East traction power supply substation of the Beijing-Hong Kong Dedicated Passenger Line in January 2015, and GICs were captured during the two geomagnetic storms on 17 March and 23 June 2015. In order to investigate the GIC flow path, both in the track circuit and in the traction network adopting the autotransformer feeding system, a GIC monitor plan was proposed for the electrical system in the Hebi East traction power supply substation. This paper analyzes the correlation between the GIC captured on 17 March and the geomagnetic data obtained from the Malingshan Geomagnetic Observatory and presents a regression analysis between the measured GIC and the calculated geoelectric fields on 23 June in the high-speed railway. The maximum GICs measured in the track circuit are 1.08 A and 1.74 A during the two geomagnetic storms. We find that it is necessary to pay attention on the throttle transformers and track circuits, as the most sensitive elements responding to the extreme geomagnetic storms in the high-speed railway.

  12. In situ health monitoring for bogie systems of CRH380 train on Beijing-Shanghai high-speed railway

    Science.gov (United States)

    Hong, Ming; Wang, Qiang; Su, Zhongqing; Cheng, Li

    2014-04-01

    Based on the authors' research efforts over the years, an in situ structural health monitoring (SHM) technique taking advantage of guided elastic waves has been developed and deployed via an online diagnosis system. The technique and the system were recently implemented on China's latest high-speed train (CRH380CL) operated on Beijing-Shanghai High-Speed Railway. The system incorporated modularized components including active sensor network, active wave generation, multi-channel data acquisition, signal processing, data fusion, and results presentation. The sensor network, inspired by a new concept—"decentralized standard sensing", was integrated into the bogie frames during the final assembly of CRH380CL, to generate and acquire bogie-guided ultrasonic waves, from which a wide array of signal features were extracted. Fusion of signal features through a diagnostic imaging algorithm led to a graphic illustration of the overall health state of the bogie in a real-time and intuitive manner. The in situ experimentation covered a variety of high-speed train operation events including startup, acceleration/deceleration, full-speed operation (300 km/h), emergency braking, track change, as well as full stop. Mock-up damage affixed to the bogie was identified quantitatively and visualized in images. This in situ testing has demonstrated the feasibility, effectiveness, sensitivity, and reliability of the developed SHM technique and the system towards real-world applications.

  13. Improved optical performance monitoring technique based on nonlinear optics for high-speed WDM Nyquist systems

    Science.gov (United States)

    Guesmi, Latifa; Menif, Mourad

    2016-04-01

    The field of fiber optics nonlinearity is more discussed last years due to such remarkable enhancement in the nonlinear processes efficiency. In this paper, and for optical performance monitoring (OPM), a new achievement of nonlinear effects has been investigated. The use of cross-phase modulation (XPM) and four-wave mixing (FWM) effects between input optical signal and inserted continuous-wave probe has proposed for impairments monitoring. Indeed, transmitting a multi-channels phase modulated signal at high data rate (1 Tbps WDM Nyquist NRZ- DP-QPSK) improves the sensitivity and the dynamic range monitoring. It was observed by simulation results that various optical parameters including optical power, wavelength, chromatic dispersion (CD), polarization mode dispersion (PMD), optical signal-to-noise ratio (OSNR), Q-factor and so on, can be monitored. Also, the effect of increasing the channel spacing between WDM signals is studied and proved its use for FWM power monitoring.

  14. Changing pattern of agitated impaired mental status in patients with advanced cancer: association with cognitive monitoring, hydration, and opioid rotation.

    Science.gov (United States)

    Bruera, E; Franco, J J; Maltoni, M; Watanabe, S; Suarez-Almazor, M

    1995-05-01

    In late 1990, it became standard practice at the palliative care unit of the Edmonton General Hospital to regularly administer the Mini-Mental State Questionnaire (MMSQ) and to undertake opioid rotation and hydration upon detection of cognitive failure. We retrospectively reviewed the charts of 117 and 162 patients admitted in 1988-1989 and 1991-1992, respectively, to assess the impact of these maneuvers on the prevalence of agitated impaired mental status (IMS). All patients underwent regular cognitive assessment in 1991-1992 versus none in 1988-1989. Seventy-three percent of patients received hydration in the second period versus 32% in the first (P prescriptions per patient, P monitoring, opioid rotation, and hydration may reduce the incidence of agitated IMS in terminal cancer patients.

  15. Condition Monitoring with WinTControl {sup trademark} in variable-speed wind power systems; Condition Monitoring mit WinTControl {sup trademark} an drehzahlveraenderlichen Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Becker; Dahlhaus, N. [Flender Service GmbH, Herne (Germany). Abt. Condition Monitoring

    2003-07-01

    In 2002, German insurance company had to pay the all-time high of about 40 million Euro for damage in wind power systems. In consequence, a servicing and maintenance clause is now included in the insurance contracts, and requirements on condition monitoring for wind power systems were defined. Condition monitoring is based on an analysis of vibrations of components that are subject to wear, i.e. gears, generators, toothing, roller bearings, rotors, and electric components. All of these have typical and significant vibration patterns which can be measured and compared in order to assess the status of a plant by high-sensitivity spectral analyses. The contribution presents the examples of reversible, constant-speed asynchronous generators with gears and of double-fed, variable-speed asynchronous generators with gears. (orig.) [German] Im Jahre 2002 haben die deutschen Versicherer fuer Schaeden an Windenergieanlagen (WEA) den Spitzenwert von rund 40 Mio. Euro bezahlt, was unter anderem dazu fuehrte, dass eine Wartungs- und Instandhaltungsklausel in die Vertraege aufgenommen und Anforderungen an ein geeignetes Condition Monitoring fuer Windenergieanlagen definiert wurden. Basis des Condition Monitoring sind 'Soll/Ist-Vergleiche' des Schwingungsverhaltens verschleissbehafteter Komponenten. Getriebe, Generatoren, Verzahnungen, Waelzlager, Rotoren und E-Technikkomponenten haben typische und signifikante Schwingungsbilder, welche bei Messung unter vergleichbaren Betriebsbedingungen eine einfache Beurteilung der Zustandveraenderung erlauben. Zustandsveraenderungen dieser Komponenten lassen sich ueber Spektralanalysen hochempfindlich verfolgen. Wie sich das Condition Monitoring an WEA dennoch realisieren laesst, wird nachfolgend an Triebstraengen mit polumschaltbaren, drehzahlstarren Asynchrongeneratoren mit Getrieben und an doppeltgespeisten, drehzahlveraenderlichen Asynchrongeneratoren mit Getrieben beschrieben. (orig.)

  16. Real-time monitoring of viscosity changes triggered by chemical reactions using a high-speed imaging method

    Directory of Open Access Journals (Sweden)

    Wooseok Jung

    2015-09-01

    Full Text Available We present a method to monitor in real time peptide self-assembly or polymerization events. The temperature controlled modification of a previously reported splash test setup using high speed imaging enables to observe and measure rheological changes in liquid samples and can, in turn, monitor a peptide self-assembly or polymerization reaction accompanied with specific changes in solution viscosity. A series of 2 mm glass beads were dropped into an Fmoc-L3-OMe (methylated Fluorenylmethyloxycarbonyl-trileucine solution mixed with Alcalase 2.4 L (EC 3.4.21.62 or first dipped in Tetramethylethylenediamine (TEMED, a catalyst for acrylamide polymerization, then dropped into acrylamide. The resulting splashes were observed using a high speed camera. The results demonstrate that the viscosity changes of the peptide sample during the peptide self-assembly or acrylamide polymerization affect the specific shape and evolution of the splashing event. Typically, the increase in viscosity while the reaction occurs decreased the size of the splash and the amount of time for the splash to reach maximum extension from the moment for the beads to impact the sample. The ability to observe rheological changes of sample state presents the opportunity to monitor the real time dynamics of peptide self-assembly or cross-polymerization.

  17. Pulsatile support using a rotary left ventricular assist device with an electrocardiography-synchronized rotational speed control mode for tracking heart rate variability.

    Science.gov (United States)

    Arakawa, Mamoru; Nishimura, Takashi; Takewa, Yoshiaki; Umeki, Akihide; Ando, Masahiko; Kishimoto, Yuichiro; Kishimoto, Satoru; Fujii, Yutaka; Date, Kazuma; Kyo, Shunei; Adachi, Hideo; Tatsumi, Eisuke

    2016-06-01

    We previously developed a novel control system for a continuous-flow left ventricular assist device (LVAD), the EVAHEART, and demonstrated that sufficient pulsatility can be created by increasing its rotational speed in the systolic phase (pulsatile mode) in a normal heart animal model. In the present study, we assessed this system in its reliability and ability to follow heart rate variability. We implanted an EVAHEART via left thoracotomy into five goats for the Study for Fixed Heart Rate with ventricular pacing at 80, 100, 120 and 140 beats/min and six goats for the Study for native heart rhythm. We tested three modes: the circuit clamp, the continuous mode and the pulsatile mode. In the pulsatile mode, rotational speed was increased during the initial 35 % of the RR interval by automatic control based on the electrocardiogram. Pulsatility was evaluated by pulse pressure and dP/dt max of aortic pressure. As a result, comparing the pulsatile mode with the continuous mode, the pulse pressure was 28.5 ± 5.7 vs. 20.3 ± 7.9 mmHg, mean dP/dt max was 775.0 ± 230.5 vs 442.4 ± 184.7 mmHg/s at 80 bpm in the study for fixed heart rate, respectively (P mode for continuous-flow LVADs reliably provided physiological pulsatility with following heart rate variability.

  18. Intra-pulp temperature increase of equine cheek teeth during treatment with motorized grinding systems: influence of grinding head position and rotational speed

    Science.gov (United States)

    2014-01-01

    Background In equine practice, teeth corrections by means of motorized grinding systems are standard procedure. The heat resulting from that treatment may cause irreparable damage to the dental pulp. It has been shown that a 5.5°C temperature rise may cause severe destruction in pulp cells. Hence, the capability to continuously form secondary dentine is lost, and may lead, due to equine-typical occlusal tooth abrasion, to an opening of the pulp cavity. To obtain reliable data on the intra-pulp increase in temperature during corrective treatments, equine cheek teeth (CT) were modified in a way (occlusal surface smoothed, apical parts detached, pulp horns standardized) that had been qualified in own former published studies. All parameters influencing the grinding process were standardized (force applied, initial temperatures, dimensions of pulp horns, positioning of grinding disk, rotational speed). During grinding experiments, imitating real dental treatments, the time span for an intra-pulp temperature increase of 5.5°C was determined. Results The minimum time recorded for an intra-pulp temperature increase of 5.5°C was 38 s in mandibular CT (buccal grinding, 12,000 rpm) and 70 s in maxillary CT (flat occlusal grinding, 12,000 rpm). The data obtained showed that doubling the rotational speed of the disk results in halving the time span after which the critical intra-pulp temperature increase in maxillary CT is reached. For mandibular CT, the time span even drops by two thirds. Conclusion The use of standardized hypsodont CT enabled comparative studies of intra-pulp heating during the grinding of occlusal tooth surfaces using different tools and techniques. The anatomical structure of the natural vital hypsodont tooth must be kept in mind, so that the findings of this study do not create a deceptive sense of security with regard to the time-dependent heating of the native pulp. PMID:24559121

  19. Displacement monitoring and modelling of a high-speed railway bridge using C-band Sentinel-1 data

    Science.gov (United States)

    Huang, Qihuan; Crosetto, Michele; Monserrat, Oriol; Crippa, Bruno

    2017-06-01

    Bridge displacement monitoring is one of the key components of bridge structural health monitoring. Traditional methods, usually based on limited sets of sensors mounted on a given bridge, collect point-like deformation information and have the disadvantage of providing incomplete displacement information. In this paper, a Persistent Scatterer Interferometry (PSI) approach is used to monitor the displacements of the Nanjing Dashengguan Yangtze River high-speed railway bridge. Twenty-nine (29) European Space Agency Sentinel-1A images, acquired from April 25, 2015 to August 5, 2016, were used in the PSI analysis. A total of 1828 measurement points were selected on the bridge. The results show a maximum longitudinal displacement of about 150 mm on each side of the bridge. The measured displacements showed a strong correlation with the environmental temperature at the time the images used were acquired, indicating that they were due to thermal expansion of the bridge. At each pier, a regression model based on the PSI-measured displacements was compared with a model based on in-situ measurements. The good agreement of these models demonstrates the capability of the PSI technique to monitor long-span railway bridge displacements. By comparing the modelled displacements and dozens of PSI measurements, we show how the performance of movable bearings can be evaluated. The high density of the PSI measurement points is advantageous for the health monitoring of the entire bridge.

  20. Bearing fault diagnosis under variable rotational speed via the joint application of windowed fractal dimension transform and generalized demodulation: A method free from prefiltering and resampling

    Science.gov (United States)

    Shi, Juanjuan; Liang, Ming; Guan, Yunpeng

    2016-02-01

    The conventional way for bearing fault diagnosis under variable rotational speed generally includes prefiltering, resampling based on shaft rotating frequency and order spectrum analysis. However, its application is confined by three major obstacles: a) knowledge-demanding parameter determination required by prefiltering, b) unavailable shaft rotating frequency for resampling as it is coupled with instantaneous fault characteristic frequency (IFCF) by a fault characteristic coefficient (FCC) which cannot be decided without knowing what fault actually exists, and c) complicated and error-prone resampling process. As such, we propose a new method to address these problems. The proposed method free from prefiltering and resampling mainly contains the following steps: a) extracting envelope by windowed fractal dimension (FD) transform, requiring no prefiltering, b) with the envelope signal, performing short time Fourier transform (STFT) to get a clear time frequency representation (TFR), from which the IFCF and the basic demodulator for generalized demodulation (GD) can be obtained, c) applying the generalized demodulation to the envelope signal with the current demodulator, converting the trajectory of the current time-frequency component into a linear path parallel to the time axis, d) frequency analyzing the demodulated signal, followed by searching the amplitude of the constant frequency where the linear path is situated. Updating demodulator via multiplying the basic demodulator by different real numbers (i.e., coefficient λ) and repeating the steps (c)-(d), the resampling-free order spectrum is then obtained. Based on the resulting spectrum, the final diagnosis decision can be made. The proposed method for its implementation on the example of simulated data is presented. Finally, experimental data are employed to validate the effectiveness of the proposed technique.

  1. Axial Speed of Sound for the Monitoring of Injured Equine Tendons: a Preliminary Study

    OpenAIRE

    VERGARI, Claudio; Pourcelot, Philippe; RAVARY-PLUMIOEN, Bérangère; DUPAYS, Anne-Gaëlle; JACQUET, Sandrine; AUDIGIE, Fabrice; Denoix, Jean-Marie; Laugier, Pascal; Mitton, David; Crevier-Denoix, Nathalie

    2012-01-01

    Equine superficial digital flexor tendons (SDFT) are often injured, and they represent an excellent model for human sport tendinopathies. While lesions can be precisely diagnosed by clinical evaluation and ultrasonography, a prognosis is often difficult to establish; the knowledge of the injured tendon's mechanical properties would help in anticipating the outcome. The objectives of the present study were to compare the axial speed of sound (SOS) measured in vivo in normal and injured tendons...

  2. Laser beam welding quality monitoring system based in high-speed (10 kHz) uncooled MWIR imaging sensors

    Science.gov (United States)

    Linares, Rodrigo; Vergara, German; Gutiérrez, Raúl; Fernández, Carlos; Villamayor, Víctor; Gómez, Luis; González-Camino, Maria; Baldasano, Arturo; Castro, G.; Arias, R.; Lapido, Y.; Rodríguez, J.; Romero, Pablo

    2015-05-01

    The combination of flexibility, productivity, precision and zero-defect manufacturing in future laser-based equipment are a major challenge that faces this enabling technology. New sensors for online monitoring and real-time control of laserbased processes are necessary for improving products quality and increasing manufacture yields. New approaches to fully automate processes towards zero-defect manufacturing demand smarter heads where lasers, optics, actuators, sensors and electronics will be integrated in a unique compact and affordable device. Many defects arising in laser-based manufacturing processes come from instabilities in the dynamics of the laser process. Temperature and heat dynamics are key parameters to be monitored. Low cost infrared imagers with high-speed of response will constitute the next generation of sensors to be implemented in future monitoring and control systems for laser-based processes, capable to provide simultaneous information about heat dynamics and spatial distribution. This work describes the result of using an innovative low-cost high-speed infrared imager based on the first quantum infrared imager monolithically integrated with Si-CMOS ROIC of the market. The sensor is able to provide low resolution images at frame rates up to 10 KHz in uncooled operation at the same cost as traditional infrared spot detectors. In order to demonstrate the capabilities of the new sensor technology, a low-cost camera was assembled on a standard production laser welding head, allowing to register melting pool images at frame rates of 10 kHz. In addition, a specific software was developed for defect detection and classification. Multiple laser welding processes were recorded with the aim to study the performance of the system and its application to the real-time monitoring of laser welding processes. During the experiments, different types of defects were produced and monitored. The classifier was fed with the experimental images obtained. Self

  3. High-Speed Monitoring of Multiple Grid-Connected Photovoltaic Array Configurations and Supplementary Weather Station.

    Science.gov (United States)

    Boyd, Matthew T

    2017-06-01

    Three grid-connected monocrystalline silicon photovoltaic arrays have been instrumented with research-grade sensors on the Gaithersburg, MD campus of the National Institute of Standards and Technology (NIST). These arrays range from 73 kW to 271 kW and have different tilts, orientations, and configurations. Irradiance, temperature, wind, and electrical measurements at the arrays are recorded, and images are taken of the arrays to monitor shading and capture any anomalies. A weather station has also been constructed that includes research-grade instrumentation to measure all standard meteorological quantities plus additional solar irradiance spectral bands, full spectrum curves, and directional components using multiple irradiance sensor technologies. Reference photovoltaic (PV) modules are also monitored to provide comprehensive baseline measurements for the PV arrays. Images of the whole sky are captured, along with images of the instrumentation and reference modules to document any obstructions or anomalies. Nearly, all measurements at the arrays and weather station are sampled and saved every 1s, with monitoring having started on Aug. 1, 2014. This report describes the instrumentation approach used to monitor the performance of these photovoltaic systems, measure the meteorological quantities, and acquire the images for use in PV performance and weather monitoring and computer model validation.

  4. Online Condition Monitoring of a Rail Fastening System on High-Speed Railways Based on Wavelet Packet Analysis.

    Science.gov (United States)

    Wei, Jiahong; Liu, Chong; Ren, Tongqun; Liu, Haixia; Zhou, Wenjing

    2017-02-08

    The rail fastening system is an important part of a high-speed railway track. It is always critical to the operational safety and comfort of railway vehicles. Therefore, the condition detection of the rail fastening system, looseness or absence, is an important task in railway maintenance. However, the vision-based method cannot identify the severity of rail fastener looseness. In this paper, the condition of rail fastening system is monitored based on an automatic and remote-sensing measurement system. Meanwhile, wavelet packet analysis is used to analyze the acceleration signals, based on which two damage indices are developed to locate the damage position and evaluate the severity of rail fasteners looseness, respectively. To verify the effectiveness of the proposed method, an experiment is performed on a high-speed railway experimental platform. The experimental results show that the proposed method is effective to assess the condition of the rail fastening system. The monitoring system significantly reduces the inspection time and increases the efficiency of maintenance management.

  5. Online Condition Monitoring of a Rail Fastening System on High-Speed Railways Based on Wavelet Packet Analysis

    Directory of Open Access Journals (Sweden)

    Jiahong Wei

    2017-02-01

    Full Text Available The rail fastening system is an important part of a high-speed railway track. It is always critical to the operational safety and comfort of railway vehicles. Therefore, the condition detection of the rail fastening system, looseness or absence, is an important task in railway maintenance. However, the vision-based method cannot identify the severity of rail fastener looseness. In this paper, the condition of rail fastening system is monitored based on an automatic and remote-sensing measurement system. Meanwhile, wavelet packet analysis is used to analyze the acceleration signals, based on which two damage indices are developed to locate the damage position and evaluate the severity of rail fasteners looseness, respectively. To verify the effectiveness of the proposed method, an experiment is performed on a high-speed railway experimental platform. The experimental results show that the proposed method is effective to assess the condition of the rail fastening system. The monitoring system significantly reduces the inspection time and increases the efficiency of maintenance management.

  6. Monitoring and analysis of thermal deformation waves with a high-speed phase measurement system.

    Science.gov (United States)

    Taylor, Lucas; Talghader, Joseph

    2015-10-20

    Thermal effects in optical substrates are vitally important in determining laser damage resistance in long-pulse and continuous-wave laser systems. Thermal deformation waves in a soda-lime-silica glass substrate have been measured using high-speed interferometry during a series of laser pulses incident on the surface. Two-dimensional images of the thermal waves were captured at a rate of up to six frames per thermal event using a quantitative phase measurement method. The system comprised a Mach-Zehnder interferometer, along with a high-speed camera capable of up to 20,000 frames-per-second. The sample was placed in the interferometer and irradiated with 100 ns, 2 kHz Q-switched pulses from a high-power Nd:YAG laser operating at 1064 nm. Phase measurements were converted to temperature using known values of thermal expansion and temperature-dependent refractive index for glass. The thermal decay at the center of the thermal wave was fit to a function derived from first principles with excellent agreement. Additionally, the spread of the thermal distribution over time was fit to the same function. Both the temporal decay fit and the spatial fit produced a thermal diffusivity of 5×10-7  m2/s.

  7. High-speed neutron radiography for monitoring the water absorption by capillarity in porous materials

    Science.gov (United States)

    Cnudde, Veerle; Dierick, Manuel; Vlassenbroeck, Jelle; Masschaele, Bert; Lehmann, Eberhard; Jacobs, Patric; Van Hoorebeke, Luc

    2008-01-01

    Fluid flow through porous natural building stones is of great importance when studying their weathering processes. Many traditional experiments based on mass changes are available for studying liquid transport in porous stones, such as the determination of the water absorption coefficient by capillarity. Because thermal neutrons experience a strong attenuation by hydrogen, neutron radiography is a suitable technique for the study of water absorption by capillarity in porous stones. However, image contrast can be impaired because hydrogen mainly scatters neutrons rather than absorbing them, resulting in a blurred image. Capillarity results obtained by neutron radiography and by the European Standard 1925 for the determination of the water absorption coefficient by capillarity for natural building stones with a variable porosity were compared. It is illustrated that high-speed neutron radiography can be a useful research tool for the visualization of internal fluid flow inside inorganic building materials such as limestones and sandstones.

  8. A Framework for Intelligent Condition-based Maintenance of Rotating Equipment using Mechanical Condition Monitoring

    Directory of Open Access Journals (Sweden)

    Tahan B. Mohammadreza

    2014-07-01

    Full Text Available The ideal end result of maintenance strategy is to increase profitability, improve product quality and ensure safety conditions. In condition-based maintenance (CBM, asset health is monitored regularly to maximize reliability and availability by determining necessary maintenance at the right time. Review of recent studies shows most of developed approaches propose a standalone system for each stage of maintenance system. In order to standardize a generic architecture for machinery CBM, this paper attempts to introduce an intelligent framework consisting of several functional modules, starting from data acquisition and ending to advisory generation, with the emphasis on approaches of condition monitoring and maintenance decision-making.

  9. Wide field monitoring of the X-ray sky using Rotation Modulation Collimators

    DEFF Research Database (Denmark)

    Lund, Niels; Brandt, Søren

    1995-01-01

    Wide field monitoring is of particular interest in X-ray astronomy due to the strong time-variability of most X-ray sources. Not only does the time-profiles of the persistent sources contain characteristic signatures of the underlying physical systems, but, additionally, some of the most intrigui...... an RMC-system of corresponding physical dimensions. But due to its simplicity, low data rate, and ability to work on spin stabilized (micro)satellites, the RMC wide field monitor may still have a role to play in the X-ray astronomy of the future....

  10. Rotation periods and astrometric motions of the Luhman 16AB brown dwarfs by high-resolution lucky-imaging monitoring

    CERN Document Server

    Mancini, L; Littlefair, S P; Southworth, J; Bozza, V; Damasso, M; Dominik, M; Hundertmark, M; Jorgensen, U G; Juncher, D; Popovas, A; Rabus, M; Rahvar, S; Schmidt, R W; Skottfelt, J; Snodgrass, C; Sozzetti, A; Alsubai, K; Bramich, D M; Novati, S Calchi; Ciceri, S; D'Ago, G; Jaimes, R Figuera; Galianni, P; Gu, S -H; Harpsoe, K; Haugbolle, T; Henning, Th; Hinse, T C; Kains, N; Korhonen, H; Scarpetta, G; Starkey, D; Surdej, J; Wang, X -B; Wertz, O

    2015-01-01

    Context. Photometric monitoring of the variability of brown dwarfs can provide useful information about the structure of clouds in their cold atmospheres. The brown-dwarf binary system Luhman 16AB is an interesting target for such a study, as its components stand at the L/T transition and show high levels of variability. Luhman 16AB is also the third closest system to the Solar system, allowing precise astrometric investigations with ground-based facilities. Aims. The aim of the work is to estimate the rotation period and study the astrometric motion of both components. Methods. We have monitored Luhman 16AB over a period of two years with the lucky-imaging camera mounted on the Danish 1.54m telescope at La Silla, through a special i+z long-pass filter, which allowed us to clearly resolve the two brown dwarfs into single objects. An intense monitoring of the target was also performed over 16 nights, in which we observed a peak-to-peak variability of 0.20 \\pm 0.02 mag and 0.34 \\pm 0.02 mag for Luhman 16A and 1...

  11. Real-time Monitoring System for Rotating Machinery with IoT-based Cloud Platform

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Haedong; Kim, Suhyun; Woo, Sunhee; Kim, Songhyun; Lee, Seungchul [Ulsan Nat’l Institute Science and Technology, Ulsan (Korea, Republic of)

    2017-06-15

    The objective of this research is to improve the efficiency of data collection from many machine components on smart factory floors using IoT(Internet of things) techniques and cloud platform, and to make it easy to update outdated diagnostic schemes through online deployment methods from cloud resources. The short-term analysis is implemented by a micro-controller, and it includes machine-learning algorithms for inferring snapshot information of the machine components. For long-term analysis, time-series and high-dimension data are used for root cause analysis by combining a cloud platform and multivariate analysis techniques. The diagnostic results are visualized in a webbased display dashboard for an unconstrained user access. The implementation is demonstrated to identify its performance in data acquisition and analysis for rotating machinery.

  12. Integrated Condition Monitoring and Prognosis Method for Incipient Defect Detection and Remaining Life Prediction of Low Speed Slew Bearings

    Directory of Open Access Journals (Sweden)

    Wahyu Caesarendra

    2017-04-01

    Full Text Available This paper presents an application of multivariate state estimation technique (MSET, sequential probability ratio test (SPRT and kernel regression for low speed slew bearing condition monitoring and prognosis. The method is applied in two steps. Step (1 is the detection of the incipient slew bearing defect. In this step, combined MSET and SPRT is used with circular-domain kurtosis, time-domain kurtosis, wavelet decomposition (WD kurtosis, empirical mode decomposition (EMD kurtosis and the largest Lyapunov exponent (LLE feature. Step (2 is the prediction of the selected features’ trends and the estimation of the remaining useful life (RUL of the slew bearing. In this step, kernel regression is used with time-domain kurtosis, WD kurtosis and the LLE feature. The application of the method is demonstrated with laboratory slew bearing acceleration data.

  13. Mineral nitrogen in the course of a cash crop and two livestock rotations - first results from the long-term monitoring Trenthorst

    OpenAIRE

    2008-01-01

    The long-term monitoring Trenthorst, situated near Lübeck in a temperate maritime climate on loamy soils, was established in 2003 and compares two cash crop and three livestock farming systems. We studied the soil mineral nitrogen contents of one cash crop and two livestock farms, specialised in dairy cows and goats/oilseeds resp., with the hypothesis that the livestock farms show a more even course of Nmin in the rotation and a higher rotation mean. The rotation average of Nmin in the cash c...

  14. On the harmonic analysis of cup anemometer rotation speed: A principle to monitor performance and maintenance status of rotating meteorological sensors

    OpenAIRE

    Pindado Carrion, Santiago; Cubas Cano, Javier; Sorribes Palmer, Felix

    2015-01-01

    The calibration results of one anemometer equipped with several rotors, varying their size, were analyzed. In each case, the 30-pulses pert turn output signal of the anemometer was studied using Fourier series decomposition and correlated with the anemometer factor (i.e., the anemometer transfer function). Also, a 3-cup analytical model was correlated to the data resulting from the wind tunnel measurements. Results indicate good correlation between the post-processed output signal and the wor...

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

    Directory of Open Access Journals (Sweden)

    Qadir Javed

    2014-01-01

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

  16. Design of hall-effect rotational speed sensor with magnetic simulation%运用磁场仿真的霍尔测速传感器设计

    Institute of Scientific and Technical Information of China (English)

    陆俊文; 刘及苟; 麦云飞

    2012-01-01

    Design and optimization of Hall-effect gear tooth sensors by using magnetic field simulation software Maxwell to make the duty cycle of output signal be 50% and have enough large sensing gap. The work theory of this sensor is translating the difference of flux density to voltage output signals. Through the calculation of the impulse number, rotational speed of the objects can be measured. According to this theory, simulation system calculates the flux density and acquires the simulated output signals through output algorithm. The deviations between the simulated and measured results of magnetic flux density are corrected by a proposed calibration algorithm of adapting simulation input parameters.%运用磁场仿真软件Maxwell对霍尔测速传感器进行设计和优化,使传感器能符合两个工作要求:50%的输出信号占空比和尽量大的测量间距.霍尔测速传感器主要工作原理是把周期性变化的磁场强度转化为电压脉冲信号,并通过脉冲数计算获得被测件的旋转速度.仿真系统和实际环境之间的误差通过校正算法进行补偿.仿真系统按照工作原理进行磁感应强度的计算,并由信号输出模块来获得模拟输出信号.

  17. Data acquisition in a high-speed rotating frame for New Mexico Institute of Mining and Technology liquid sodium αω dynamo experiment.

    Science.gov (United States)

    Si, Jiahe; Colgate, Stirling A; Li, Hui; Martinic, Joe; Westpfahl, David

    2013-10-01

    New Mexico Institute of Mining and Technology liquid sodium αω-dynamo experiment models the magnetic field generation in the universe as discussed in detail by Colgate, Li, and Pariev [Phys. Plasmas 8, 2425 (2001)]. To obtain a quasi-laminar flow with magnetic Reynolds number R(m) ~ 120, the dynamo experiment consists of two co-axial cylinders of 30.5 cm and 61 cm in diameter spinning up to 70 Hz and 17.5 Hz, respectively. During the experiment, the temperature of the cylinders must be maintained to 110 °C to ensure that the sodium remains fluid. This presents a challenge to implement a data acquisition (DAQ) system in such high temperature, high-speed rotating frame, in which the sensors (including 18 Hall sensors, 5 pressure sensors, and 5 temperature sensors, etc.) are under the centrifugal acceleration up to 376g. In addition, the data must be transmitted and stored in a computer 100 ft away for safety. The analog signals are digitized, converted to serial signals by an analog-to-digital converter and a field-programmable gate array. Power is provided through brush/ring sets. The serial signals are sent through ring/shoe sets capacitively, then reshaped with cross-talk noises removed. A microcontroller-based interface circuit is used to decode the serial signals and communicate with the data acquisition computer. The DAQ accommodates pressure up to 1000 psi, temperature up to more than 130 °C, and magnetic field up to 1000 G. First physics results have been analyzed and published. The next stage of the αω-dynamo experiment includes the DAQ system upgrade.

  18. Data acquisition in a high-speed rotating frame for New Mexico Institute of Mining and Technology liquid sodium αω dynamo experiment

    Science.gov (United States)

    Si, Jiahe; Colgate, Stirling A.; Li, Hui; Martinic, Joe; Westpfahl, David

    2013-10-01

    New Mexico Institute of Mining and Technology liquid sodium αω-dynamo experiment models the magnetic field generation in the universe as discussed in detail by Colgate, Li, and Pariev [Phys. Plasmas 8, 2425 (2001)]. To obtain a quasi-laminar flow with magnetic Reynolds number Rm ˜ 120, the dynamo experiment consists of two co-axial cylinders of 30.5 cm and 61 cm in diameter spinning up to 70 Hz and 17.5 Hz, respectively. During the experiment, the temperature of the cylinders must be maintained to 110 °C to ensure that the sodium remains fluid. This presents a challenge to implement a data acquisition (DAQ) system in such high temperature, high-speed rotating frame, in which the sensors (including 18 Hall sensors, 5 pressure sensors, and 5 temperature sensors, etc.) are under the centrifugal acceleration up to 376g. In addition, the data must be transmitted and stored in a computer 100 ft away for safety. The analog signals are digitized, converted to serial signals by an analog-to-digital converter and a field-programmable gate array. Power is provided through brush/ring sets. The serial signals are sent through ring/shoe sets capacitively, then reshaped with cross-talk noises removed. A microcontroller-based interface circuit is used to decode the serial signals and communicate with the data acquisition computer. The DAQ accommodates pressure up to 1000 psi, temperature up to more than 130 °C, and magnetic field up to 1000 G. First physics results have been analyzed and published. The next stage of the αω-dynamo experiment includes the DAQ system upgrade.

  19. Experimental Study the Conveying Capability of Screw Conveyor Affected by Rotation Speed and Feeding Amount%螺旋输送装置转速和喂入量对输送性能的影响试验研究

    Institute of Scientific and Technical Information of China (English)

    乌兰图雅; 王春光; 赵圆圆; 王金莲

    2015-01-01

    This dissertation applies the experimental study to studying the performance of conveying affected by feeding a-mount and screw speed.The higher screw rotational speed, the greater power consumption.But the throughput increases with infinite speed, and the speed of 102 r/min when reach maximum throughput.The greater feeding amount, the grea-ter throughput,and greater the power consumption of conveyor Therefore should chose the reasonable rotation speed and feeding amount that can meet the production requirements in practical application.%通过试验,研究喂入量和螺旋转速对输送量和功耗的影响。试验结果表明:螺旋转速越高、输送装置的功耗越大,但输送量不随转速无限增大,当转速达到102 r/min 时输送量达到最大值;喂入量越大,输送量越大,输送装置的功耗也随之增加。因此,在实际应用中能满足生产需求的情况下,转速和喂入量不宜过高。

  20. Label-free cardiac contractility monitoring for drug screening applications based on compact high-speed lens-free imaging

    Science.gov (United States)

    Pauwelyn, Thomas; Reumers, Veerle; Vanmeerbeeck, Geert; Stahl, Richard; Janssens, Stefan; Lagae, Liesbet; Braeken, Dries; Lambrechts, Andy

    2015-03-01

    Cardiotoxicity is the major cause of drug withdrawal from the market, despite rigorous toxicity testing during the drug development process. Existing safety screening techniques, some of which are based on simplified cellular assays, others on electrical (impedance) or optical (fluorescent microscopy) measurements, are either too limited in throughput or offer too poor predictability of toxicity to be applied on large numbers of compounds in the early stage of drug development. We present a compact optical system for direct (label-free) monitoring of fast cellular movements that enable low cost and high throughput drug screening. Our system is based on a high-speed lens-free in-line holographic microscope. When compared to a conventional microscope, the system can combine adequate imaging resolution (5.5 μm pixel pitch) with a large field-of-view (63.4 mm2) and high speed (170 fps) to capture physical cell motion in real-time. This combination enables registration of cardiac contractility parameters such as cell contraction frequency, total duration, and rate and duration of both contraction and relaxation. The system also quantifies conduction velocity, which is challenging in existing techniques. Additionally, to complement the imaging hardware we have developed image processing software that extracts all the contractility parameters directly from the raw interference images. The system was tested with varying concentration of the drug verapamil and at 100 nM, showed a decrease in: contraction frequency (-23.3% +/- 13%), total duration (-21% +/- 5%), contraction duration (-19% +/- 6%) and relaxation duration (-21% +/- 8%). Moreover, contraction displacement ceased at higher concentrations.

  1. Compact high-speed MWIR spectrometer applied to monitor CO2 exhaust dynamics from a turbojet engine

    Science.gov (United States)

    Linares-Herrero, R.; Vergara, G.; Gutiérrez Álvarez, R.; Fernández Montojo, C.; Gómez, L. J.; Villamayor, V.; Baldasano Ramírez, A.; Montojo, M. T.; Archilla, V.; Jiménez, A.; Mercader, D.; González, A.; Entero, A.

    2013-05-01

    Dfgfdg Due to international environmental regulations, aircraft turbojet manufacturers are required to analyze the gases exhausted during engine operation (CO, CO2, NOx, particles, unburned hydrocarbons (aka UHC), among others).Standard procedures, which involve sampling the gases from the exhaust plume and the analysis of the emissions, are usually complex and expensive, making a real need for techniques that allow a more frequent and reliable emissions measurements, and a desire to move from the traditional gas sampling-based methods to real time and non-intrusive gas exhaust analysis, usually spectroscopic. It is expected that the development of more precise and faster optical methods will provide better solutions in terms of performance/cost ratio. In this work the analysis of high-speed infrared emission spectroscopy measurements of plume exhaust are presented. The data was collected during the test trials of commercial engines carried out at Turbojet Testing Center-INTA. The results demonstrate the reliability of the technique for studying and monitoring the dynamics of the exhausted CO2 by the observation of the infrared emission of hot gases. A compact (no moving parts), high-speed, uncooled MWIR spectrometer was used for the data collection. This device is capable to register more than 5000 spectra per second in the infrared band ranging between 3.0 and 4.6 microns. Each spectrum is comprised by 128 spectral subbands with aband width of 60 nm. The spectrometer operated in a passive stand-off mode and the results from the measurements provided information of both the dynamics and the concentration of the CO2 during engine operation.

  2. Optical transmission versus ac magnetization measurements for monitoring colloidal Ni nanorod rotational dynamics

    Science.gov (United States)

    Gratz, M.; Tschöpe, A.

    2017-01-01

    Ni nanorods with an average length transmission of nanorod colloidal dispersions in alternating magnetic fields were measured and analyzed with the objective of comparing the intrinsic Brownian relaxation times obtained with the two methods. The different physical origin of the measured signal, related to different moments of the orientation distribution function, and the non-linear effects expected for the large magnetic moments of the Ni nanorods at common field amplitudes required a comprehensive modelling. The time-dependent magnetization and optical transmission in ac magnetic fields was derived by numerical solution of the Fokker-Planck equation. The simulated time-dependent magnetization and optical transmission at a given frequency and field amplitude were analyzed analogous to experimental data to determine characteristic relaxation frequencies. Empirical relationships were derived which enabled extraction of the intrinsic Brownian relaxation time from the characteristic frequencies measured in the non-linear regime. Despite large differences in the characteristic frequencies obtained from magnetization and optical transmission measurements, the retrieved intrinsic Brownian relaxation times were found to agree well. The potential of ac magnetic field-dependent optical transmission for biosensing applications was demonstrated by monitoring the adsorption of the protein gelatine on the nanorod labels.

  3. 某起动机转速切断装置自动测控系统设计%Automatic Measurement Control System Design for A Starter Rotational Speed Shutoff Device

    Institute of Scientific and Technical Information of China (English)

    徐民

    2012-01-01

    Adopted high speed single chip C8051F020 and VNH3SP30 packaging bridge motor driven chip control electric machine velocity abreast row rotational speed data acquisition, ground measurement control system for the aircraft starter rotational speed shutoff device is developed. Practical operation shows that the system is capable of ensuring proof speed rise slope of consistency, catching cutoff RPM level reliably, stable work and friendly man-machine interface.%采用高速单片机C8051F020和VNH3SP30单封装全桥电机驱动芯片控制电机上升速度并进行转速等数据采集,设计出某飞机起动机部件-转速切断装置组件地面测控系统.实际使用证明该系统能确保转速上升斜率的一致性,捕捉到的切断转速值可靠,并且工作稳定、性价比高、人机界面友好.

  4. Experimental study of the influence of rotating speed on the performance of micro water jet pump%转速对微型喷水推进泵性能影响的试验研究

    Institute of Scientific and Technical Information of China (English)

    胡海鹏; 石海峡; 柴立平; 李绍旭; 夏天

    2016-01-01

    Hydraulic performance of micro water jet pump influences the efficiency of water jet propul-sion systems directly .In this paper ,based on the model of micro water jet pump with power of less than 400 W ,the motor characteristic under different rotating speeds was acquired by motor test ,the specialized test bench of external characteristic was built according to the features of low lift and large flow rate ,and then the key parameters such as pressure and flow were collected ,thus the characteris-tic curve of water jet pump under different rotating speeds could be achieved .The research results showed that the rotating speed had a prominent effect on the efficiency of water jet pump ,the optimal efficiency area moved towards large flow area and the peak of efficiency increased with the increase of rotating speed .Once the water jet pump was designed ,the work area with optimal efficiency could be found by the optimization control of rotating speed .Consequently the run duration of water jet pump under different applications could increase remarkably .%微型喷水推进泵的水力特性直接影响着喷水推进系统的效率。文章以功率小于400 W 的微型喷水推进泵为模型,通过电机试验得出电机在不同转速情况下的特性,并针对喷水推进泵大流量、低扬程的特点搭建专门外特性试验台,对压力、流量等参数进行测量采集,得出不同转速情况下喷水推进泵的特性曲线。研究结果表明,喷水推进泵的转速对效率有着重要的影响,随着转速的增加,最优效率向大流量区域偏移,效率峰值也随着转速的增加而增大。在喷水推进泵设计完成后可以通过转速的优化控制得出最优的效率工作区,提高不同应用环境下喷水推进泵的工作时间。

  5. SU-E-T-483: In Vivo Dosimetry of Conventional and Rotational Intensity Modulated Radiotherapy Using Integral Quality Monitor (IQM)

    Energy Technology Data Exchange (ETDEWEB)

    Lin, L; Qian, J; Gonzales, R; Keck, J; Armour, E; Wong, J [Johns Hopkins University, Baltimore, MD (United States)

    2015-06-15

    Purpose: To investigate the accuracy, sensitivity and constancy of integral quality monitor (IQM), a new system for in vivo dosimetry of conventional intensity modulated radiation therapy (IMRT) or rotational volumetric modulated arc therapy (VMAT) Methods: A beta-version IQM system was commissioned on an Elekta Infinity LINAC equipped with 160-MLCs Agility head. The stationary and rotational dosimetric constancy of IQM was evaluated, using five-field IMRT and single-or double-arc VMAT plans for prostate and head-and-neck (H&N) patients. The plans were delivered three times over three days to assess the constancy of IQM response. Picket fence (PF) fields were used to evaluate the sensitivity of detecting MLC leaf errors. A single leaf offset was intentionally introduced during delivery of various PF fields with segment apertures of 3×1, 5×1, 10×1, and 24×1cm2. Both 2mm and 5mm decrease in the field width were used. Results: Repeated IQM measurements of prostate and H&N IMRT deliveries showed 0.4 and 0.5% average standard deviation (SD) for segment-by-segment comparison and 0.1 and 0.2% for cumulative comparison. The corresponding SDs for VMAT deliveries were 6.5, 9.4% and 0.7, 1.3%, respectively. Statistical analysis indicates that the dosimetric differences detected by IQM were significant (p < 0.05) in all PF test deliveries. The largest average IQM signal response of a 2 mm leaf error was found to be 2.1% and 5.1% by a 5mm leaf error for 3×1 cm2 field size. The same error in 24×1 cm2 generates a 0.7% and 1.4% difference in the signal. Conclusion: IQM provides an effective means for real-time dosimetric verification of IMRT/ VMAT treatment delivery. For VMAT delivery, the cumulative dosimetry of IQM needs to be used in clinical practice.

  6. Simulation Study of a New Method to Synchronously Control Rotate Speed and Power of a Steam Turbine%汽轮机转速与功率同步控制新方法的仿真研究

    Institute of Scientific and Technical Information of China (English)

    史小平; 王子才

    2003-01-01

    经典的汽轮机调节系统在实现功率跟踪负荷变化的同时会不可避免地引起转速的变化,从而引起电网频率的变化.应用线性系统极点配置的方法,提出了一种既能使汽机功率跟踪负荷,同时又能对汽机转速按指令曲线进行控制的新方法.用这种方法设计的调节系统就能省去二次调频的环节.计算机仿真的结果证明了本文所提出方法的正确性和有效性.%The frequency of the electric network will inevitably fluctuate because of rotate speed variation of a steam turbine, while its classical regulation system is accomplishing matching between its power and the referenced electric load. A new method is developed to synchronously control rotate speed and power of a steam turbine with pole placement technique of linear system. With this new control method, not only the rotate speed of a steam turbine can be controlled according to its instruction curve, but also its power can be synchronously controlled to quickly track the electric load without additional component of the frequency regulation. The computer simulation verifies the correctness and the effectiveness of the presented new control method.

  7. 模糊自整定PID的航空发动机转速控制研究%Rotating Speed Control for Aero-engine Based on Fuzzy Serf-tuning PID Controller

    Institute of Scientific and Technical Information of China (English)

    乔伯真; 缑林峰

    2013-01-01

    Due to the strong nonlinearity and time - variation of aero - engine, it is difficult for the rotating speed control system based on the method of fixed parameters PID to possess the consistent performance. In consideration of this problem, a fuzzy self - tuning PID controller was proposed. On the base of the input errors and its changing rate, a group of online self - tuning rules were built for PID parameters. And the fuzzy reasoning methods were used to calculate the new parameters in real - time. Then combining with the nonlinear real - time model of an core - engine, the rotating speed cascade control hardware system was simulated in the loop. The result indicates that the fuzzy self - tuning PID controller realizes the online tuning of parameters with a small switchover disturbance and meets the requirements of the rotate speed control in the full envelope.%航空发动机具有强非线性和强时变性的特点,使用定参数PID方法的转速控制系统的性能在全飞行包线内难以保证.针对上述问题,提出设计模糊自整定PID控制器,利用输入误差及变化率建立一组PID参数在线调整规则,运用模糊推理方法实时进行参数自整定.结合某型航空发动机核心机非线性实时模型,进行转速串级控制硬件在回路仿真.结果表明,提出的模糊自整定PID控制方法实现了控制器参数在线调整,参数切换扰动小,满足全包线内转速控制的指标要求.

  8. Design Method for Contra-Rotating Propellers for High-Speed Crafts: Revising the Original Lerbs Theory in a Modern Perspective

    Directory of Open Access Journals (Sweden)

    Stefano Brizzolara

    2012-01-01

    Full Text Available The main theoretical and numerical aspects of a design method for optimum contrar-rotating (CR propellers for fast marine crafts are presented. We propose a reformulated version of a well-known design theory for contra-rotating propellers, by taking advantage of a new fully numerical algorithm for the calculation of the mutually induced velocities and introducing new features such as numerical lifting surface corrections, use of an integrated modern cavitation/strength criteria, a modified method to consider different numbers of blades among the two propellers, and to allow for an unloading function in the search for the optimal circulation distribution. The paper first introduces the main theoretical principles of the new methods and then discusses the influence of the main design parameters on an emblematic example of application in the case of counter rotating propellers for a pod propulsor designed for fast planing crafts (35 knots and above.

  9. Intensive sound speed monitoring in ocean and its impact on the GPS/acoustic seafloor geodetic measurement

    Science.gov (United States)

    Kido, Motoyuki

    2016-04-01

    GPS/acoustic (GPS/A) technique, based on GPS positioning and acoustic ranging, is now getting a popular tool to measure seafloor crustal movement. Several groups in the world have been intensively conducted campaign surveys in the region of scientifically interest. As the technology of measurement has been matured and plenty of data are accumulated, researchers are now aware of the limit of its precision mainly due to unexpected undulation of sound speed in ocean, which significantly degrades acoustic ranging. If sound speed structure keeps its figure during survey period, e.g., more than a couple of hours, it can be estimated by a moving survey to get sufficient paths from various directions to illustrate the structure. However the sound speed structure often varies quickly with in a hour due to internal gravitational wave excited by interaction of tidal current and seafloor topography. In this case one cannot separate temporal and spatial variations. We revisited our numerous sound speed profile data derived from numbers of XBT measurements, which were concurrently carried out with GPS/A survey along the Nankai Trough and Japan Trench. Among the measurements, we found notably short-period variation in sound speed profile through intensive XBT survey repeatedly cast every 6 minutes for one hour, which also appeared in residuals in traveltime of acoustic ranging. The same feature is also found in more moderate rate for semidiurnal undulation, in which vertical oscillation of the middle of the profile can be clearly seen rather than variation of absolute sound speed. This also reflects traveltime residuals in the GPS/A measurement. These typical frequencies represent dominant wavelengths of spatial sound speed variation. In the latter, local horizontal variation can be negligible in the vicinity of a point survey area and the traditional analysis can be applicable that assumes time-varying stratified sound speed structure. In the former case, on the contrary, local

  10. 基于LabVIEW的旋转机械转子振动监测系统%Vibration Monitoring System for Rotating Machine's Rotor Based on LabVIEW

    Institute of Scientific and Technical Information of China (English)

    王彦兵; 李慧敏; 丁彩红

    2011-01-01

    采用传感器和信号调理技术对旋转机械转子振动的各种信号进行采集、处理,并利用LabVIEW强大的信号处理、分析和数学运算功能对信号进行显示、分析,实现了在线转子的运转状况的监测,设计出了基于LabVIEW的旋转机械转子振动的监测系统.该系统可连续测量和监视转子振动有关的各类参量:转速、轴振、轴位移等,具有直观的显示界面、强大的信号分析以及数据存储管理功能.能及时识别旋转机械设备的异常状态,保证设备安全可靠地运行,并可以为控制设备运行于最优状态以及早期诊断设备故障提供依据.%This paper used sensor and signal conditioning technology for acquiring and processing a variety of rotor vibration signals of rotating machine.It used the LahVIEW' s powerful function of signal processing,analyais and mathematical operation to display and analyze the signal, realized monitoring the work status of online rotor,designed the vibration monitoring system for rotating machine' s rotor based on LabVIEW.This system can measure and monitor various types of rotor vibration parameters in continuously,speed,rotor vibration, axial displacement, with the intuitive display interface, powerful signal analysis ability and data 0storage management functions.It can identify the abnormal states of rotating mechanical equipment to ensure the safty and reliahility of equipment operation,provide the basis to control the equipment running at an optimal condition and diagnose the early equipment fault.

  11. Study on rotating speed control of DC motor in welding system%焊接系统中直流电机转速控制的研究

    Institute of Scientific and Technical Information of China (English)

    李林

    2011-01-01

    在CO2焊接和埋弧焊接系统中,精确控制行走电机和送丝电机的速度是提高焊接质量的重要保证,传统直流电机转速控制方法是通过转速表测量电机的转速后反馈控制,该控制方法存在精度差、不易调试等缺点.采用锁相环闭环控制直流电机的转速,其控制方法是:由于行走电机和送丝电机的转速比较慢,因此,编码器不通过减速机构直接安装在直流电机的转轴上,从而测得电机的转速,与设定速度作PI控制产生PWM波形控制H型双极可逆驱动电路开关管的导通时间,从而精确控制直流电机的转速.试验表明,该方法控制精确高,能稳定、可靠、实时地控制电机转速.%In C02 welding and submerged arc welding system,precise control of the speed of the moving motor and wire feeding motor is an important guarantee to improve the welding quality of dc motor speed control,the traditional method is detecting motor speed with tachometer to feedback control system, this control method is poor, not easy to adjust the control accuracy .This article adopts the phase locked loop closed-loop to control dc motor speed,and its control method is:because of the moving motor and wire feeding motor speed is slower,therefore,not through the slow institutions encoder directly installed in dc motor shaft,which measured the speed of the motor,and setting speed make PI control to produce the PWM waveform to control H bipolar reversible driving circuit switch's runs.Thus accurately control dc motor speed,the experimental result indicates that the method can accurately control high, stable,real-time controlling motor speed.

  12. Modulation of the shape and speed of a chemical wave in an unstirred Belousov-Zhabotinsky reaction by a rotating magnet.

    Science.gov (United States)

    Okano, Hideyuki; Kitahata, Hiroyuki

    2013-04-01

    The objective of this study was to observe whether a rotating magnetic field (RMF) could change the anomalous chemical wave propagation induced by a moderate-intensity gradient static magnetic field (SMF) in an unstirred Belousov-Zhabotinsky (BZ) reaction. The application of the SMF (maximum magnetic flux density = 0.22 T, maximum magnetic flux density gradient = 25.5 T/m, and peak magnetic force product (flux density × gradient) = 4 T(2) /m) accelerated the propagation velocity in a two-dimensional pattern. Characteristic anomalous patterns of the wavefront shape were generated and the patterns were dependent on the SMF distribution. The deformation and increase in the propagation velocity were diminished by the application of an RMF at a rotation rate of 1 rpm for a few minutes. Numerical simulation by means of the time-averaged value of the magnetic flux density gradient or the MF gradient force over one rotation partially supported the experimental observations. These considerations suggest that RMF exposure modulates the chemical wave propagation and that the degree of modulation could be, at least in part, dependent on the time-averaged MF distribution over one rotation. Bioelectromagnetics 34:220-230, 2013. © 2012 Wiley Periodicals, Inc. Copyright © 2012 Wiley Periodicals, Inc.

  13. Deconstructing Mental Rotation

    DEFF Research Database (Denmark)

    Larsen, Axel

    2014-01-01

    A random walk model of the classical mental rotation task is explored in two experiments. By assuming that a mental rotation is repeated until sufficient evidence for a match/mismatch is obtained, the model accounts for the approximately linearly increasing reaction times (RTs) on positive trials...... alignment take place during fixations at very high speed....

  14. Granulation of core particles suitable for film coating by agitation fluidized bed III. Effect of scale, agitator rotational speed and blade shape on granule properties and development of a high accuracy scale-up theory.

    Science.gov (United States)

    Hamashita, Tomohiro; Ono, Tetsuo; Ono, Masaki; Tsunenari, Yoshinobu; Aketo, Takao; Watano, Satoru

    2009-04-01

    The preparation of core particles suitable for subsequent film coating was examined using different scales of agitation fluidized beds. Specifically, the effects of agitator rotational speed and agitator blade shape in different scales of granulators on granule properties such as mass median diameter, apparent density, friability and shape factor were studied. As the agitator rotational speed was increased or when the agitator blade height and angle were large, the mass median diameter and friability of the granules decreased, while the apparent density and shape factor increased, in a manner independent of the vessel size because the granules were subjected to greater compression, shearing and rolling effects. The same core particles could not be prepared using granulators with different vessel sizes by simply adopting a conventional scale-up theory(1,2)) based on kinetic energy similarity. Here, a novel scale-up theory that takes into account agitator blade shape factors is proposed.(3)) When the two scale-up theories were compared, our new theory was capable of predicting the granule properties more accurately than the conventional theory. By adopting this novel theory, the same core particles could be prepared under different operating conditions in any scale of granulator.

  15. An investigational study of minimum rotational pump speed to avoid retrograde flow in three centrifugal blood pumps in a pediatric extracorporeal life support model.

    Science.gov (United States)

    Clark, Joseph B; Guan, Yulong; McCoach, Robert; Kunselman, Allen R; Myers, John L; Undar, Akif

    2011-05-01

    During extracorporeal life support with centrifugal blood pumps, retrograde pump flow may occur when the pump revolutions decrease below a critical value determined by the circuit resistance and the characteristics of the pump. We created a laboratory model to evaluate the occurrence of retrograde flow in each of three centrifugal blood pumps: the Rotaflow, the CentriMag, and the Bio-Medicus BP-50. At simulated patient pressures of 60, 80, and 100 mmHg, each pump was evaluated at speeds from 1000 to 2200 rpm and flow rates were measured. Retrograde flow occurred at low revolution speeds in all three centrifugal pumps. The Bio-Medicus pump was the least likely to demonstrate retrograde flow at low speeds, followed by the Rotaflow pump. The CentriMag pump showed the earliest transition to retrograde flow, as well as the highest degree of retrograde flow. At every pump speed evaluated, the Bio-Medicus pump delivered the highest antegrade flow and the CentriMag pump delivered the least.

  16. Towards an automatic system for monitoring of CN2 and wind speed profiles with GeMS

    CERN Document Server

    Masciadri, E; Guesalaga, A; Turchi, A

    2016-01-01

    Wide Field Adaptive Optics (WFAO) systems represent the more sophisticated AO systems available today at large telescopes. A critical aspect for these WFAO systems in order to deliver an optimised performance is the knowledge of the vertical spatiotemporal distribution of the CN2 and the wind speed. Previous studies (Cortes et al., 2012) already proved the ability of GeMS (the Gemini Multi-Conjugated AO system) in retrieving CN2 and wind vertical stratification using the telemetry data. To assess the reliability of the GeMS wind speed estimates a preliminary study (Neichel et al., 2014) compared wind speed retrieved from GeMS with that obtained with the atmospherical model Meso-Nh on a small sample of nights providing promising results. The latter technique is very reliable for the wind speed vertical stratification. The model outputs gave, indeed, an excellent agreement with a large sample of radiosoundings (~ 50) both in statistical terms and on individual flights (Masciadri et al., 2013). Such a tool can t...

  17. Resistance and Stock Propulsion on the High Speed Sealift (HSS) Hybrid Contra-Rotating Shaft-Pod (HCRSP) Concept, Model 5653-3A

    Science.gov (United States)

    2008-09-01

    pod transmission dynamometers, of 177 lbf. thrust (T) / 112 in-lbf. torque (Q) capacity, manufactured by Force Technology of Denmark. The two pods were... spurred the exploration of alternative ship designs as well as non-conventional propulsion designs on monohulls. The high speed sealift mission profile...complexity required of the coaxial shaftline drive system, and induced problems with expensive gear sets, bearings and seals. Using a pod to drive the aft

  18. Methods for Expanding Rotary Wing Aircraft Health and Usage Monitoring Systems to the Rotating Frame through Real-time Rotor Blade Kinematics Estimation

    Science.gov (United States)

    Allred, Charles Jefferson

    Since the advent of Health and Usage Monitoring Systems (HUMS) in the early 1990's, there has been a steady decrease in the number of component failure related helicopter accidents. Additionally, measurable cost benefits due to improved maintenance practices based on HUMS data has led to a desire to expand HUMS from its traditional area of helicopter drive train monitoring. One of the areas of greatest interest for this expansion of HUMS is monitoring of the helicopter rotor head loads. Studies of rotor head load and blade motions have primarily focused on wind tunnel testing with technology which would not be applicable for production helicopter HUMS deployment, or measuring bending along the blade, rather than where it is attached to the rotor head and the location through which all the helicopter loads pass. This dissertation details research into finding methods for real time methods of estimating rotor blade motion which could be applied across helicopter fleets as an expansion of current HUMS technology. First, there is a brief exploration of supporting technologies which will be crucial in enabling the expansion of HUMS from the fuselage of helicopters to the rotor head: wireless data transmission and energy harvesting. A brief overview of the commercially available low power wireless technology selected for this research is presented. The development of a relatively high-powered energy harvester specific to the motion of helicopter rotor blades is presented and two different prototypes of the device are shown. Following the overview of supporting technologies, two novel methods of monitoring rotor blade motion in real time are developed. The first method employs linear displacement sensors embedded in the elastomer layers of a high-capacity laminate bearing of the type commonly used in fully articulated rotors throughout the helicopter industry. The configuration of these displacement sensors allows modeling of the sensing system as a robotic parallel

  19. A Tentative Study on Dynamics of a New Parallel NC Machine Tool with Long Travel, Large Rotating Angle and High Moving Speed

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In view of the structure of traditional five-coord in ate machine tool, the work-piece and machine tool often move along their respec tive guides simultaneously on the whole. In this kind of machine structure, the total mass of moving parts including work-pieces, fixtures, rotating table, wor king table and so on is often very large. Besides, the elastic reform of transmi ssion and the viscous friction force of the guide can not be ignored. As a resul t, the machine tool can not move with high velocity and...

  20. High speed, high-resolution fiber Bragg grating sensing system for monitoring of weigh-in-motion devices

    Science.gov (United States)

    Tosi, D.; Olivero, M.; Perrone, G.; Vallan, A.

    2011-05-01

    We present a fast high-resolution fiber Bragg grating sensing system for weigh-in-motion (WIM) application. The proposed system makes use of standard telecom photonics components operating at high speed and with insufficient resolution; then, using signal processing we artificially improve the accuracy of the system down to 1 μɛ. This way, the proposed architecture overcomes the state of the art of optical systems for WIM, which cannot cope with both high resolution and high frequency requirements. The developed system has been applied to a prototype weigh-in-motion device, which consists of a road speed bump. Structural deformations of the bump when perturbed by a thin-footmark load are well reproduced. Using multiple Bragg grating sensors, it is possible to unambiguously determine position and weight of a moving load on the bump with accuracy of 0.2 - 1.2 kg.

  1. High-speed 100 MHz strain monitor using fiber Bragg grating and optical filter for magnetostriction measurements under ultrahigh magnetic fields

    Science.gov (United States)

    Ikeda, Akihiko; Nomura, Toshihiro; Matsuda, Yasuhiro H.; Tani, Shuntaro; Kobayashi, Yohei; Watanabe, Hiroshi; Sato, Keisuke

    2017-08-01

    A high-speed 100 MHz strain monitor using a fiber Bragg grating, an optical filter, and a mode-locked optical fiber laser has been devised, whose resolution is Δ L /L ˜1 0-4. The strain monitor is sufficiently fast and robust for the magnetostriction measurements of materials under ultrahigh magnetic fields generated with destructive pulse magnets, where the sweep rate of the magnetic field is in the range of 10-100 T/μ s. As a working example, the magnetostriction of LaCoO3 was measured at room temperature, 115 K, and 7 ˜ 4.2 K up to a maximum magnetic field of 150 T. The smooth dependence on the squared magnetic field and the first-order transition were observed at 115 K and 7 ˜ 4.2 K, respectively, reflecting the field-induced spin state evolution.

  2. Numerical simulation of influence of rotational speed change on performance of centrifugal pump%转速变化对离心泵性能影响的数值模拟

    Institute of Scientific and Technical Information of China (English)

    赵万勇; 马鹏飞; 白双宝; 马达

    2012-01-01

    A 1200S56 double-suction centrifugal pump was chosen as the research object and the Reynolds time-average equation, standard k-ε turbulence mode and the SIMPLEC algorithm were used to simulate its three-dimensional full-flow passage of its 5 similar working point groups under 8 rotational speeds. According to the simulation results, the change of internal flow field with similar working points of the pump was analyzed. It was found that the internal flow patterns are highly similar in similar working points and the result was consistent with the similarity theory of pump. Meanwhile, performance parameters in different working points were calculated by using simulation result. Then the error of numerical simulation result from that of scaling law was also calculated. The result showed that the efficiency of the pump decreased by a very small quantity and most of relative errors of its head and power were within 1 % as the rotational speed changing, meaning that the scaling law could reflect the change of performance parameters as the rotational speed changing.%以1200S56型双吸离心泵为研究对象,通过Fluent软件,运用雷诺时均方程和RNGk-ε湍流模型,结合SIMPLEC算法,对其8个转速下的5组相似工况进行三维全流道数值模拟.由模拟结果分析相似工况点上泵内部流场的变化情况,发现在相似工况下泵内部流场高度相似,符合泵的相似理论.由数值模拟结果计算各工况的性能参数,得出数值模拟预测值相对于比例定律计算值的误差.结果显示,转速变化时,泵的效率下降很小,而扬程、功率的相对误差多数都在1%以内,说明比例定律能较好地反映泵的性能参数随转速的变化情况.

  3. 高速高精度固定角度旋转CORDIC算法的设计与实现%Design and ImpIementation of CORDIC AIgorithm for High Speed and Precision Fixed AngIe of Rotation

    Institute of Scientific and Technical Information of China (English)

    张朝柱; 韩吉南; 燕慧智

    2016-01-01

    Coordinate Rotation Digital Computer (CORDIC)algorithm for fixed angle of rotation has been widely ap-plied in many fields,including digital signal processing,image processing and robotics.CORDIC algorithm,based on fixed an-gle of rotation,has an advantage of high data throughput,but it takes up much more hardware resources.To remedy these prob-lems,a hybrid CORDIC algorithm is proposed in this paper,which separates the angle rotation into two steps,unidirectional an-gle rotations and angle estimation ones.According to the under-damping theory,the unidirectional phase rotations are employed to realize the fixed angle of rotation,which reduces the stage of pipeline and judgment of sign bit.Through the binary represen-tation,the constant factor will be fixed.According to the phase mapping relationship,the high speed and precision fixed angle of rotation is completed.Finally the hybrid algorithm is implemented on a hardware platform and the experimental results show that it can further reduce the number of iterations and resource consumption and obtain high though-put rate.%固定角度旋转的CORDIC(Coordinate Rotation Digital Computer)算法已经广泛的应用于高速数字信号处理、图像处理、机器人学等领域。针对固定角度旋转CORDIC算法在相位旋转过程中,存在数据吞吐率较高、占用硬件资源较多且资源消耗量大等缺点,提出了利用混合CORDIC算法,将角度旋转分为单向角度旋转和一次角度估计旋转两部分。本文根据欠阻尼理论,将固定角度旋转采用单向旋转CORDIC算法实现,减少了流水线的级数和迭代符号位的判决,然后通过对角度估计旋转的二进制表示,修正常数因子,再根据角度映射关系进行相关处理,完成高速高精度坐标旋转。最后在硬件平台上进行了仿真实验。实验结果表明,在误差范围一定的前提下,混合算法进一步的减少了迭代次数,并且资源消耗较

  4. Solar UV exposure at eye is different from environmental UV: diurnal monitoring at different rotation angles using a manikin.

    Science.gov (United States)

    Hu, Liwen; Gao, Qian; Gao, Na; Liu, Guangcong; Wang, Yang; Gong, Huizhi; Liu, Yang

    2013-01-01

    Solar ultraviolet radiation (UVR) promotes pterygium and cataract development in the human eye. When outdoors, people are subject to varying ocular UVR exposure intensity depending on time of day and orientation to the sun. To assess this variability, a manikin eye was exposed to solar UVR at 12 rotation angles relative to the sun with a solar elevation angle (SEA) ranging from 24.6° to 88.2°. At rotation angles of 0°, 30°, and 330°, the diurnal variation of ocular UVR exposure intensity showed a bimodal distribution that peaked at a SEA of about 40°, which was 3 to 4 hr both before and after noon. This timing differed from peak environmental UVR exposure intensity. At the other rotation angles, diurnal variations in ocular UV exposure exhibited unimodal curves, with maximum intensity around noon, the same as for environmental UVR. Thus, the idea that UVR exposure is most intense at midday is true for skin surfaces positioned somewhat horizontally but not for the eyes in a 60° arc with a centerline toward the sun (i.e., ranging 30° clockwise or counter-clockwise from the centerline). Maintaining certain orientations relative to the sun's position (for example, being clockwise or counter-clockwise by 30° from the sun) should effectively reduce ocular UVR exposure, especially at times when the SEA is 40°.

  5. Extracting invariable fault features of rotating machines with multi-ICA networks

    Institute of Scientific and Technical Information of China (English)

    焦卫东; 杨世锡; 吴昭同

    2003-01-01

    This paper proposes novel multi-layer neural networks based on Independent Component Analysis for feature extraction of fault modes. By the use of ICA, invariable features embedded in multi-channel vibration measurements under different operating conditions (rotating speed and/or load) can be captured together.Thus, stable MLP classifiers insensitive to the variation of operation conditions are constructed. The successful results achieved by selected experiments indicate great potential of ICA in health condition monitoring of rotating machines.

  6. Motor current signature analysis for gearbox condition monitoring under transient speeds using wavelet analysis and dual-level time synchronous averaging

    Science.gov (United States)

    Bravo-Imaz, Inaki; Davari Ardakani, Hossein; Liu, Zongchang; García-Arribas, Alfredo; Arnaiz, Aitor; Lee, Jay

    2017-09-01

    This paper focuses on analyzing motor current signature for fault diagnosis of gearboxes operating under transient speed regimes. Two different strategies are evaluated, extensively tested and compared to analyze the motor current signature in order to implement a condition monitoring system for gearboxes in industrial machinery. A specially designed test bench is used, thoroughly monitored to fully characterize the experiments, in which gears in different health status are tested. The measured signals are analyzed using discrete wavelet decomposition, in different decomposition levels using a range of mother wavelets. Moreover, a dual-level time synchronous averaging analysis is performed on the same signal to compare the performance of the two methods. From both analyses, the relevant features of the signals are extracted and cataloged using a self-organizing map, which allows for an easy detection and classification of the diverse health states of the gears. The results demonstrate the effectiveness of both methods for diagnosing gearbox faults. A slightly better performance was observed for dual-level time synchronous averaging method. Based on the obtained results, the proposed methods can used as effective and reliable condition monitoring procedures for gearbox condition monitoring using only motor current signature.

  7. Prediction algorithm for rotational speed of workpiece's revolving shaftwith numerical cam grinder%凸轮轴磨床工件旋转轴转速预测算法的研究

    Institute of Scientific and Technical Information of China (English)

    王洪; 戴瑜兴; 许世雄; 王东昱

    2011-01-01

    Acceleration and deceleration of grinding in cam based on method of cubic B-spline curve interpolation is weak, which is easy to grind much and insufficiently.According to the mathematic model of cam grinding,the theoretical and practi cable speed,acceleration and the differential acceleration of cam's feed shaft is analyzed.A processing method of forecasting rotational speed of workpiece is proposed,and the rotational workpiece is automatically underspeeded when the speed is rap idly variated.The cam grinding software is designed based on this adaptive interpolation algorithm and Matrix VB,and then it is applied to the YTMK-CNC8336,which is digital and high speed cam grinder.The testing results show that the error of cam grinding with this proposed method is less than 0.01 mm,and the roughness is less.%采用三次B样条曲线插补的凸轮磨削加减速能力不足,易产生过磨和少磨.根据凸轮磨削的数学模型,分析了砂轮进给轴运动的理论与实际速度、加速度、加加速度,提出了一种预测工件旋转轴转速的加工方法,在速度变化剧烈处自动降低工件旋转轴转速,以避免加速度和加加速度的变化对伺服系统造成的机械冲击,利用MatrixVB控件编程技术,设计了凸轮轴磨削软件,并将其移植到YTMK-CNC8326全数控高速凸轮轴磨床中.测试表明,采用该方法磨削的凸轮轴型线误差小于±0.01 mm,工件表面粗糙度得到明显改善,实现了凸轮轴的精密加工.

  8. Field on monitoring partial discharges in rotating machines; Experiencias en campo en monitorizacion de descargas parciales en maquinas rotativas

    Energy Technology Data Exchange (ETDEWEB)

    Cano Gonzalez, J. C.; Blokhintsev, I.

    2010-07-01

    The partial discharge monitoring is now an accepted technique in the market, however there are different measurement solutions. Equipment manufacturers partial discharge using different equipment, different measurement frequencies, different sensors and different solutions to noise.

  9. Extraction method for unbalanced signal in a dual-rotor system with little rotating speed difference%微速差双转子系统不平衡信号提取方法

    Institute of Scientific and Technical Information of China (English)

    李传江; 张自强; 费敏锐; 胡豁生

    2013-01-01

    微速差双转子系统的两个频率相近不平衡信号形成拍振,传统不平衡信号提取方法的精度和快速性不佳.提出一种以数字带通滤波后数据为样本的改进型Prony方法用于识别两个转子的频率,可以有效解决微差双转子系统中转差不易测量的难题,把最小二乘方法用于识别已知频率的两个不平衡信号的幅值和相位,可以在噪声背景下快速、准确的实现参数估计.最后给出了详细的仿真结果和分析,证明了该方法的正确性.%Two unbalanced signals with adjacent frequencies form a beat signal in a dual-rotor system with slightly different rotating speeds.The precision and efficiency of the traditional extraction methods for unbalanced signals are not good.Here,an improved Prony method was presented to identify frequencies of two rotors based on bandpass filtered data,it could solve the problen that little rotating speed difference is not easy to be measured.The least square method was used to recognize amplitude and phase of a beat signal with known frequencies and to realize parametric estimations accurately and quickly.At last,simulations and analyses were given to prove the correctness of the proposed method.

  10. 基于MSP430单片机的电机智能转速监测系统设计%Design of A Intelligent Motor Speed Monitoring System Based on MCU MSP430

    Institute of Scientific and Technical Information of China (English)

    淮文军; 石贵江; 於汝彪

    2012-01-01

    设计一种由MSP430单片机构成的智能转速监测系统.该系统由与电机同轴的齿轮信号盘和霍尔转速传感器组成,对霍尔转速传感器输出的信号进行滤波和整形,使处理后的信号转换成标准的方波信号,隔离后由单片机计数,通过LED显示实时转速值.与传统的测速仪相比,可设定转速监测范围、存储设定参数,当电机超速时,可发出报警信号.试验证明,该系统测速精度高,电机状态监测可靠.%An intelligent speed monitoring system was introduced. Taking single-clip MSP430F169 as core, the part of Speed detection consists of gear signal plate Coaxial with the motor and Hall speed sensor. For the output signal from the sensor filtering and shaping, so that the processed signal into a standard square wave signal and chip count after the isolation, the value of real-time speed is display through the LED circuit. Compared with the traditional speed measuring instrument, the scope of speed monitoring on motor can be set, the parameter can be stored. The equipment can send an alarm signal when the speed of motor exceeds the set speed range. A test proved that the intelligent speed monitoring system has a high speed precision and reliability on motor condition monitoring.

  11. Test research of raising speed rotation, precision and capacity for workpiece table%工作台提高转速、精度、承载能力试验研究

    Institute of Scientific and Technical Information of China (English)

    胡巍; 季卫东; 吴鹏; 杨春晖

    2011-01-01

    In order to adapt to the market need, hydrostatic guideway of workpiece table adopts the new structure design for speed up of heavy duty double columns vertical lathe. The height of 3.5 m, 5 m and 6.3 m of double columns vertical lathes respectively raise the rotation speed to 100 r/min, 80 r/min, 50 r/min after the research of structure changing which proves the rationality of new structure.%为适应市场需求,对重型双柱立式车床进行提速,工作台静压导轨采用了全新结构设计。对改进后的结构进行试验,双柱立车3.5 m、5 m、6.3 m成功将转速分别提高到100r/min、80r/min、50r/min,证明新结构合理可行。

  12. High-speed monitoring of the crystallinity change in poly(lactic acid) during photodegradation by using a newly developed wide area NIR imaging system (Compovision).

    Science.gov (United States)

    Ishikawa, Daitaro; Furukawa, Daiki; Wei, Tseng Tsai; Reddy, Kummetha Raghunatha; Motomura, Asako; Igarashi, Yoko; Sato, Harumi; Kazarian, Sergei G; Ozaki, Yukihiro

    2015-01-01

    We aimed to achieve wide area rapid monitoring of the crystallinity change in poly(lactic acid) (PLA) during photodegradation caused by ultraviolet (UV) light by using a newly developed near-infrared (NIR) camera (Compovison). Several kinds of PLA samples with different crystallinities and their blends with poly[(3)-(R)-hydroxybutyrate] were prepared. Their two-dimensional NIR spectra in the 1,000-2,350-nm region were measured by Compovision at a 5-min interval during photolysis. An intensity decrease of the band in the 1,900-1,925-nm region due to the second overtone of the C = O stretching vibration of PLA was observed during photolysis. This suggests that an anhydride carbonyl is produced during photolysis. The NIR image of the crystallinity change monitored by the band at 1,917 nm in the standard normal variate spectra clearly shows the inhomogeneity of crystal evolution. A logarithmic increase was observed for all identified areas in the PLA film; however, the time to reach the maximum crystallinity was slightly different according to the initial crystallinity of the sample. It is likely that the initial crystallinity of the sample influences the degradation speed more than the degradation amount. These imaging results have provided fundamental chemical insights into the photolytic process for PLA, and at the same time they have demonstrated that the two-dimensional spectral data obtained by Compovision are useful for process monitoring of polymers.

  13. Synchronised electrical monitoring and high speed video of bubble growth associated with individual discharges during plasma electrolytic oxidation

    Science.gov (United States)

    Troughton, S. C.; Nominé, A.; Nominé, A. V.; Henrion, G.; Clyne, T. W.

    2015-12-01

    Synchronised electrical current and high speed video information are presented from individual discharges on Al substrates during PEO processing. Exposure time was 8 μs and linear spatial resolution 9 μm. Image sequences were captured for periods of 2 s, during which the sample surface was illuminated with short duration flashes (revealing bubbles formed where the discharge reached the surface of the coating). Correlations were thus established between discharge current, light emission from the discharge channel and (externally-illuminated) dimensions of the bubble as it expanded and contracted. Bubbles reached radii of 500 μm, within periods of 100 μs, with peak growth velocity about 10 m/s. It is deduced that bubble growth occurs as a consequence of the progressive volatilisation of water (electrolyte), without substantial increases in either pressure or temperature within the bubble. Current continues to flow through the discharge as the bubble expands, and this growth (and the related increase in electrical resistance) is thought to be responsible for the current being cut off (soon after the point of maximum radius). A semi-quantitative audit is presented of the transformations between different forms of energy that take place during the lifetime of a discharge.

  14. 闭磁路磁电式转速转矩传感器的研究%Research of Rotational Speed and Sensor with Closed Magnetic Circuit

    Institute of Scientific and Technical Information of China (English)

    徐光卫; 宋春华

    2012-01-01

    在磁电式转速转矩传感器的设计中,齿的个数是一个重要的参数而闭磁路式传感器的磁路计算比较复杂,没有很好的确定齿数的公式.针对上述问题,提出了一种基于有限元分析软件Ansoft Maxwell确定闭磁路磁电式传感器齿数的方法,通过使用Ansoft Maxwell建立一种量程为20 N·m任意齿数的闭磁路磁电式传感器的三维模型并进行仿真,根据仿真结果计算出其合适的齿数并进一步以得出的齿数建立新模型进行仿真试验确认了该方法的可行性.实验表明这种齿数确定方法具有较强的实用性.%In the design of magnetic-electric speed torque sensor, the number of teeth is an important parameter, but the closed magnetic circuit magnetic sensor is too complicated to use a good formula to determine the number of teeth. A method based on finite element analysis software Ansoft Maxwell was proposed to determine the number of teeth. A range of 20 N· m at random number of teeth of the closed magnetic circuit magnetic sensor and three-dimensional model simulation was established by using Ansoft Maxwell. The appropriate number of teeth was calculated based on the simulation results. The calculated number was used to create a new simulation model for the purpose of confirming the feasibility of this method. Experiments show the practicability of the teeth number determination.

  15. A High-Speed, Real-Time Visualization and State Estimation Platform for Monitoring and Control of Electric Distribution Systems: Implementation and Field Results

    Energy Technology Data Exchange (ETDEWEB)

    Lundstrom, Blake; Gotseff, Peter; Giraldez, Julieta; Coddington, Michael

    2015-10-05

    Continued deployment of renewable and distributed energy resources is fundamentally changing the way that electric distribution systems are controlled and operated; more sophisticated active system control and greater situational awareness are needed. Real-time measurements and distribution system state estimation (DSSE) techniques enable more sophisticated system control and, when combined with visualization applications, greater situational awareness. This paper presents a novel demonstration of a high-speed, real-time DSSE platform and related control and visualization functionalities, implemented using existing open-source software and distribution system monitoring hardware. Live scrolling strip charts of meter data and intuitive annotated map visualizations of the entire state (obtained via DSSE) of a real-world distribution circuit are shown. The DSSE implementation is validated to demonstrate provision of accurate voltage data. This platform allows for enhanced control and situational awareness using only a minimum quantity of distribution system measurement units and modest data and software infrastructure.

  16. Device of Induction Motor Speed Measurement and Rotor Faults Monitoring%异步电机转速测量及转子故障监测仪

    Institute of Scientific and Technical Information of China (English)

    赵加友; 毛谦敏; 金荣泰

    2015-01-01

    为了简化异步电机转速测量,同时能够实时在线监测电机运行状态,设计了一种基于电机电流检测法的测量装置。它以STM32单片机为处理核心,采用电流传感器获取异步电机电流信号并结合希尔伯特变换、自相乘变换、频谱细分算法等信号处理方法,实时有效地计算出电机转速,并且准确判断电机是否存在转子故障。实验结果表明,该系统最大转速测量误差为4 r/min,且故障判断出错率小。%A measurement device was designed based on motor stator current analysis method to simplify the speed measure-ment of induction motor and monitor the motor running state online at the same time.It took STM32 microcontroller as the core pro-cessor,used a current sensor to react current signal of the induction motor and combined Hilbert transform,self-multiplying trans-form with spectrum subdivision algorithm and so on to process signal.With all above,the device can calculate the real-time speed effectively and estimate whether there is a fault of motor rotor accurately.The experimental results show that the system has a maxi-mum speed measurement error of 4rpm and the error rate of fault judgment is small.

  17. Monitoring subunit rotation in single FRET-labeled FoF1-ATP synthase in an anti-Brownian electrokinetic trap

    Science.gov (United States)

    Heitkamp, Thomas; Sielaff, Hendrik; Korn, Anja; Renz, Marc; Zarrabi, Nawid; Börsch, Michael

    2013-02-01

    FoF1-ATP synthase is the membrane protein catalyzing the synthesis of the 'biological energy currency' adenosine triphosphate (ATP). The enzyme uses internal subunit rotation for the mechanochemical conversion of a proton motive force to the chemical bond. We apply single-molecule Förster resonance energy transfer (FRET) to monitor subunit rotation in the two coupled motors F1 and Fo. Therefore, enzymes have to be isolated from the plasma membranes of Escherichia coli, fluorescently labeled and reconstituted into 120-nm sized lipid vesicles to yield proteoliposomes. These freely diffusing proteoliposomes occasionally traverse the confocal detection volume resulting in a burst of photons. Conformational dynamics of the enzyme are identified by sequential changes of FRET efficiencies within a single photon burst. The observation times can be extended by capturing single proteoliposomes in an anti-Brownian electrokinetic trap (ABELtrap, invented by A. E. Cohen and W. E. Moerner). Here we describe the preparation procedures of FoF1-ATP synthase and simulate FRET efficiency trajectories for 'trapped' proteoliposomes. Hidden Markov Models are applied at signal-to-background ratio limits for identifying the dwells and substeps of the rotary enzyme when running at low ATP concentrations, excited by low laser power, and confined by the ABELtrap.

  18. Efficient monitoring of blood-stage infection in a malaria rodent model by the rotating-crystal magneto-optical method

    CERN Document Server

    Orban, Agnes; Albuquerque, Inês S; Butykai, Adam; Kezsmarki, Istvan; Hänscheid, Thomas

    2015-01-01

    Global research efforts have been focused on the simultaneous improvement of the efficiency and sensitivity of malaria diagnosis in resource-limited settings and for the active case detection of asymptomatic infections. A recently developed magneto-optical (MO) method allows the high-sensitivity detection of malaria pigment (hemozoin) crystals in blood via their magnetically induced rotational motion. The evaluation of the method using synthetic $\\beta$-hematin crystals and P. falciparum in vitro cultures implies its potential for in-field diagnosis. Here, we study the performance of the method in monitoring the in vivo onset and progression of the blood stage infection using a malaria mouse model. We found that the MO method can detect the first generation of intraerythrocytic parasites at the ring stage 61-66 hours after sporozoite injection demonstrating better sensitivity than light microscopy and flow cytometry. MO measurements performed after treatment of severe P. berghei infections show that the clear...

  19. At-line bioprocess monitoring by immunoassay with rotationally controlled serial siphoning and integrated supercritical angle fluorescence optics

    Energy Technology Data Exchange (ETDEWEB)

    Nwankire, Charles E., E-mail: charles.nwankire@dcu.ie [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Donohoe, Gerard G.; Zhang, Xin [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Biotechnology, Dublin City University, Glasnevin, Dublin 9 (Ireland); Siegrist, Jonathan [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Somers, Martin [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); Kurzbuch, Dirk [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Monaghan, Ruairi [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); Kitsara, Maria [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Burger, Robert [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Hearty, Stephen [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Biotechnology, Dublin City University, Glasnevin, Dublin 9 (Ireland); Murrell, Julie; Martin, Christopher; Rook, Martha [EMD Millipore Corporation, 80 Ashby Road, Bedford, MA (United States); and others

    2013-06-05

    Graphical abstract: A serial siphon based centrifugal microfluidic platform for the quantitative at-line monitoring of human immunoglobulin G (hIgG) in typical industrial bioprocess samples using a prototype optical SAF detection system. -- Highlights: •Sample-to-answer microfluidic lab-on-a-disc device for at-line bioprocess monitoring. •Centrifugally integrated and automated reagent delivery by serial-siphon valves. •Supercritical angle fluorescence optics embedded on centrifugal platform. •Development of fluorescence-linked-immunosorbent assay on human immunoglobulin G. •Bioprocess samples from industrial reactor determined on the prototype system. -- Abstract: In this paper we report a centrifugal microfluidic “lab-on-a-disc” system for at-line monitoring of human immunoglobulin G (hIgG) in a typical bioprocess environment. The novelty of this device is the combination of a heterogeneous sandwich immunoassay on a serial siphon-enabled microfluidic disc with automated sequential reagent delivery and surface-confined supercritical angle fluorescence (SAF)-based detection. The device, which is compact, easy-to-use and inexpensive, enables rapid detection of hIgG from a bioprocess sample. This was achieved with, an injection moulded SAF lens that was functionalized with aminopropyltriethoxysilane (APTES) using plasma enhanced chemical vapour deposition (PECVD) for the immobilization of protein A, and a hybrid integration with a microfluidic disc substrate. Advanced flow control, including the time-sequenced release of on-board liquid reagents, was implemented by serial siphoning with ancillary capillary stops. The concentration of surfactant in each assay reagent was optimized to ensure proper functioning of the siphon-based flow control. The entire automated microfluidic assay process is completed in less than 30 min. The developed prototype system was used to accurately measure industrial bioprocess samples that contained 10 mg mL{sup −1} of hIgG.

  20. High-Speed Edge Trimming of CFRP and Online Monitoring of Performance of Router Tools Using Acoustic Emission.

    Science.gov (United States)

    Prakash, Rangasamy; Krishnaraj, Vijayan; Zitoune, Redouane; Sheikh-Ahmad, Jamal

    2016-09-26

    Carbon fiber reinforced polymers (CFRPs) have found wide-ranging applications in numerous industrial fields such as aerospace, automotive, and shipping industries due to their excellent mechanical properties that lead to enhanced functional performance. In this paper, an experimental study on edge trimming of CFRP was done with various cutting conditions and different geometry of tools such as helical-, fluted-, and burr-type tools. The investigation involves the measurement of cutting forces for the different machining conditions and its effect on the surface quality of the trimmed edges. The modern cutting tools (router tools or burr tools) selected for machining CFRPs, have complex geometries in cutting edges and surfaces, and therefore a traditional method of direct tool wear evaluation is not applicable. An acoustic emission (AE) sensing was employed for on-line monitoring of the performance of router tools to determine the relationship between AE signal and length of machining for different kinds of geometry of tools. The investigation showed that the router tool with a flat cutting edge has better performance by generating lower cutting force and better surface finish with no delamination on trimmed edges. The mathematical modeling for the prediction of cutting forces was also done using Artificial Neural Network and Regression Analysis.

  1. High-Speed Edge Trimming of CFRP and Online Monitoring of Performance of Router Tools Using Acoustic Emission

    Directory of Open Access Journals (Sweden)

    Rangasamy Prakash

    2016-09-01

    Full Text Available Carbon fiber reinforced polymers (CFRPs have found wide-ranging applications in numerous industrial fields such as aerospace, automotive, and shipping industries due to their excellent mechanical properties that lead to enhanced functional performance. In this paper, an experimental study on edge trimming of CFRP was done with various cutting conditions and different geometry of tools such as helical-, fluted-, and burr-type tools. The investigation involves the measurement of cutting forces for the different machining conditions and its effect on the surface quality of the trimmed edges. The modern cutting tools (router tools or burr tools selected for machining CFRPs, have complex geometries in cutting edges and surfaces, and therefore a traditional method of direct tool wear evaluation is not applicable. An acoustic emission (AE sensing was employed for on-line monitoring of the performance of router tools to determine the relationship between AE signal and length of machining for different kinds of geometry of tools. The investigation showed that the router tool with a flat cutting edge has better performance by generating lower cutting force and better surface finish with no delamination on trimmed edges. The mathematical modeling for the prediction of cutting forces was also done using Artificial Neural Network and Regression Analysis.

  2. High speed imaging, lightning mapping arrays and thermal imaging: a synergy for the monitoring of electrical discharges at the onset of volcanic explosions

    Science.gov (United States)

    Gaudin, Damien; Cimarelli, Corrado; Behnke, Sonja; Cigala, Valeria; Edens, Harald; McNutt, Stefen; Smith, Cassandra; Thomas, Ronald; Van Eaton, Alexa

    2017-04-01

    Volcanic lightning is being increasingly studied, due to its great potential for the detection and monitoring of ash plumes. Indeed, it is observed in a large number of ash-rich volcanic eruptions and it produces electromagnetic waves that can be detected remotely in all weather conditions. Electrical discharges in volcanic plume can also significantly change the structural, chemical and reactivity properties of the erupted material. Although electrical discharges are detected in various regions of the plume, those happening at the onset of an explosion are of particular relevance for the early warning and the study of volcanic jet dynamics. In order to better constrain the electrical activity of young volcanic plumes, we deployed at Sakurajima (Japan) in 2015 a multiparametric set-up including: i) a lightning mapping array (LMA) of 10 VHF antennas recording the electromagnetic waves produced by lightning at a sample rate of 25 Msps; ii) a visible-light high speed camera (5000 frames per second, 0.5 m pixel size, 300 m field of view) shooting short movies (approx. duration 1 s) at different stages of the plume evolution, showing the location of discharges in relation to the plume; and iii) a thermal camera (25 fps, 1.5 m pixel size, 800 m field of view) continuously recording the plume and allowing the estimation of its main source parameters (volume, rise velocity, mass eruption rate). The complementarity of these three setups is demonstrated by comparing and aggregating the data at various stages of the plume development. In the earliest stages, the high speed camera spots discrete small discharges, that appear on the LMA data as peaks superimposed to the continuous radio frequency (CRF) signal. At later stages, flashes happen less frequently and increase in length. The correspondence between high speed camera and LMA data allows to define a direct correlation between the length of the flash and the intensity of the electromagnetic signal. Such correlation is

  3. Complex Demodulation in Monitoring Earth Rotation by VLBI: Testing the Algorithm by Analysis of Long Periodic EOP Components

    Science.gov (United States)

    Wielgosz, A.; Brzeziński, A.; Böhm, S.

    2016-12-01

    The complex demodulation (CD) algorithm is an efficient tool for extracting the diurnal and subdiurnal components of Earth rotation from the routine VLBI observations (Brzeziński, 2012). This algorithm was implemented by Böhm et al (2012b) into a dedicated version of the VLBI analysis software VieVs. The authors processed around 3700 geodetic 24-hour observing sessions in 1984.0-2010.5 and estimated simultaneously the time series of the long period components as well as diurnal, semidiurnal, terdiurnal and quarterdiurnal components of polar motion (PM) and universal time UT1. This paper describes the tests of the CD algorithm by checking consistency of the low frequency components of PM and UT1 estimated by VieVS CD and those from the IERS and IVS combined solutions. Moreover, the retrograde diurnal component of PM demodulated from VLBI observations has been compared to the celestial pole offsets series included in the IERS and IVS solutions. We found for all three components a good agreement of the results based on the CD approach and those based on the standard parameterization recommended by the IERS Conventions (IERS, 2010) and applied by the IERS and IVS. We conclude that an application of the CD parameterization in VLBI data analysis does not change those components of EOP which are included in the standard adjustment, while enabling simultaneous estimation of the high frequency components from the routine VLBI observations. Moreover, we deem that the CD algorithm can also be implemented in analysis of other space geodetic observations, like GNSS or SLR, enabling retrieval of subdiurnal signals in EOP from the past data.

  4. HIGH SPEED CAMERA

    Science.gov (United States)

    Rogers, B.T. Jr.; Davis, W.C.

    1957-12-17

    This patent relates to high speed cameras having resolution times of less than one-tenth microseconds suitable for filming distinct sequences of a very fast event such as an explosion. This camera consists of a rotating mirror with reflecting surfaces on both sides, a narrow mirror acting as a slit in a focal plane shutter, various other mirror and lens systems as well as an innage recording surface. The combination of the rotating mirrors and the slit mirror causes discrete, narrow, separate pictures to fall upon the film plane, thereby forming a moving image increment of the photographed event. Placing a reflecting surface on each side of the rotating mirror cancels the image velocity that one side of the rotating mirror would impart, so as a camera having this short a resolution time is thereby possible.

  5. Speed control system for an access gate

    Science.gov (United States)

    Bzorgi, Fariborz M.

    2012-03-20

    An access control apparatus for an access gate. The access gate typically has a rotator that is configured to rotate around a rotator axis at a first variable speed in a forward direction. The access control apparatus may include a transmission that typically has an input element that is operatively connected to the rotator. The input element is generally configured to rotate at an input speed that is proportional to the first variable speed. The transmission typically also has an output element that has an output speed that is higher than the input speed. The input element and the output element may rotate around a common transmission axis. A retardation mechanism may be employed. The retardation mechanism is typically configured to rotate around a retardation mechanism axis. Generally the retardation mechanism is operatively connected to the output element of the transmission and is configured to retard motion of the access gate in the forward direction when the first variable speed is above a control-limit speed. In many embodiments the transmission axis and the retardation mechanism axis are substantially co-axial. Some embodiments include a freewheel/catch mechanism that has an input connection that is operatively connected to the rotator. The input connection may be configured to engage an output connection when the rotator is rotated at the first variable speed in a forward direction and configured for substantially unrestricted rotation when the rotator is rotated in a reverse direction opposite the forward direction. The input element of the transmission is typically operatively connected to the output connection of the freewheel/catch mechanism.

  6. Development and application of a high-speed, high-resolution data acquisition system for monitoring power at the service entrance to buildings

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, T.R.

    1995-02-01

    A non-intrusive load monitoring system (NILMS) was developed and tested to determine its capabilities and examine ways that the system can supplement the understanding of how energy is used in a building. The investigation of the system as a method for obtaining short-term building energy use and demand data faster, as less cost, with less complexity, and less intrusively than from conventional submetering is described in this report. Data acquisition hardware and software, a power transducer, and current transformers were assembled into a system that could be used to sample the instantaneous real and reactive power coming into a building. The system was used to collect power profiles at a commercial and a residential building. The NILMS can sample power at low speeds (one sample per hour or less) and at speeds exceeding 100 Hz. Large changes in building power such as those due to central heating and cooling systems, water heaters, or banks of lights can easily be discriminated from total building power profiles collected by the system. Smaller loads, less than 1 or 2 kW, can be resolved when there is little ``noise`` in the power profile. Very small loads, less than 100 W, can be resolved in a residential application. Resolution becomes more difficult as larger and more frequent fluctuations occur. The ability of the system to easily collect valuable, short-term building power profiles, which permit individual loads to be determined (resolved), makes the system attractive for a number of applications. The system could prove very useful for measuring short-term energy use and demand, assisting building energy auditors in assessing building deficiencies, providing short-term performance data for validating engineering-based savings estimates and calibrating computer-based building performance models, and for validating, developing, and/or improving building and building system operating strategies.

  7. Development and application of a high-speed, high-resolution data acquisition system for monitoring power at the service entrance to buildings

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, T.R.

    1995-02-01

    A non-intrusive load monitoring system (NILMS) was developed and tested to determine its capabilities and examine ways that the system can supplement the understanding of how energy is used in a building. The investigation of the system as a method for obtaining short-term building energy use and demand data faster, as less cost, with less complexity, and less intrusively than from conventional submetering is described in this report. Data acquisition hardware and software, a power transducer, and current transformers were assembled into a system that could be used to sample the instantaneous real and reactive power coming into a building. The system was used to collect power profiles at a commercial and a residential building. The NILMS can sample power at low speeds (one sample per hour or less) and at speeds exceeding 100 Hz. Large changes in building power such as those due to central heating and cooling systems, water heaters, or banks of lights can easily be discriminated from total building power profiles collected by the system. Smaller loads, less than 1 or 2 kW, can be resolved when there is little ``noise`` in the power profile. Very small loads, less than 100 W, can be resolved in a residential application. Resolution becomes more difficult as larger and more frequent fluctuations occur. The ability of the system to easily collect valuable, short-term building power profiles, which permit individual loads to be determined (resolved), makes the system attractive for a number of applications. The system could prove very useful for measuring short-term energy use and demand, assisting building energy auditors in assessing building deficiencies, providing short-term performance data for validating engineering-based savings estimates and calibrating computer-based building performance models, and for validating, developing, and/or improving building and building system operating strategies.

  8. High-resolution calculations of the solar global convection with the reduced speed of sound technique: I. The structure of the convection and the magnetic field without the rotation

    CERN Document Server

    Hotta, H; Yokoyama, T

    2014-01-01

    We carry out non-rotating high-resolution calculations of the solar global convection, which resolve convective scales of less than 10 Mm. To cope with the low Mach number conditions in the lower convection zone, we use the reduced speed of sound technique (RSST), which is simple to implement and requires only local communication in the parallel computation. In addition, the RSST allows us to expand the computational domain upward to about $0.99 R_{\\odot}$ as it can also handle compressible flows. Using this approach, we study the solar convection zone on the global scale, including small-scale near-surface convection. In particular, we investigate the influence of the top boundary condition on the convective structure throughout the convection zone as well as on small-scale dynamo action. Our main conclusions are: 1. The small-scale downflows generated in the near-surface layer penetrate into deeper layers to some extent and excite small-scale turbulence in the region $>0.9R_\\odot$, where $R_\\odot$ is the so...

  9. Speeding Up

    Institute of Scientific and Technical Information of China (English)

    YU SHUJUN

    2010-01-01

    In the wake of the global financial crisis, China has amazed the world with the speed of its economic recovery. But what has been even more surprising is the speed of its railway evolution. The unveiling of the 1,069-km Wuhan-Guangzhou High-speed Railway on December 26, 2009 pushed China's high-speed rail sys-tem-the total mileage, the average speed and the technology-to rank first in the world almost overnight.

  10. Modeling the Relationship between Vibration Features and Condition Parameters Using Relevance Vector Machines for Health Monitoring of Rolling Element Bearings under Varying Operation Conditions

    Directory of Open Access Journals (Sweden)

    Lei Hu

    2015-01-01

    Full Text Available Rotational speed and load usually change when rotating machinery works. Both this kind of changing operational conditions and machine fault could make the mechanical vibration characteristics change. Therefore, effective health monitoring method for rotating machinery must be able to adjust during the change of operational conditions. This paper presents an adaptive threshold model for the health monitoring of bearings under changing operational conditions. Relevance vector machines (RVMs are used for regression of the relationships between the adaptive parameters of the threshold model and the statistical characteristics of vibration features. The adaptive threshold model is constructed based on these relationships. The health status of bearings can be indicated via detecting whether vibration features exceed the adaptive threshold. This method is validated on bearings running at changing speeds. The monitoring results show that this method is effective as long as the rotational speed is higher than a relative small value.

  11. Light weight, high-speed, and self-powered wireless fiber optic sensor (WiFOS) structural health monitor system for avionics and aerospace environments

    Science.gov (United States)

    Mendoza, Edgar A.; Kempen, Cornelia; Sun, Sunjian; Esterkin, Yan

    2014-09-01

    This paper describes recent progress towards the development of an innovative light weight, high-speed, and selfpowered wireless fiber optic sensor (WiFOS™) structural health monitor system suitable for the onboard and in-flight unattended detection, localization, and classification of load, fatigue, and structural damage in advanced composite materials commonly used in avionics and aerospace systems. The WiFOS™ system is based on ROI's advancements on monolithic photonic integrated circuit microchip technology, integrated with smart power management, on-board data processing, wireless data transmission optoelectronics, and self-power using energy harvesting tools such as solar, vibration, thermoelectric, and magneto-electric. The self-powered, wireless WiFOS™ system offers a versatile and powerful SHM tool to enhance the reliability and safety of avionics platforms, jet fighters, helicopters, commercial aircraft that use lightweight composite material structures, by providing comprehensive information about the structural integrity of the structure from a large number of locations. Immediate SHM applications are found in rotorcraft and aircraft, ships, submarines, and in next generation weapon systems, and in commercial oil and petrochemical, aerospace industries, civil structures, power utilities, portable medical devices, and biotechnology, homeland security and a wide spectrum of other applications.

  12. Speed control at low wind speeds for a variable speed fixed pitch wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Rosmin, N.; Watson, S.J.; Tompson, M. [Loughborough Univ., Loughborough, Leicestershire (United Kingdom)

    2010-03-09

    The maximum power regulation below rated wind speed is regulated by changing the rotor/generator speed at large frequency range in a fixed pitch, variable speed, stall-regulated wind turbine. In order to capture the power at a maximum value the power coefficient is kept at maximum peak point by maintaining the tip speed ratio at its optimum value. The wind industry is moving from stall regulated fixed speed wind turbines to newer improved innovative versions with better reliability. While a stall regulated fixed pitch wind turbine is among the most cost-effective wind turbine on the market, its problems include noise, severe vibrations, high thrust loads and low power efficiency. Therefore, in order to improve such drawbacks, the rotation of the generator speed is made flexible where the rotation can be controlled in variable speed. This paper discussed the development of a simulation model which represented the behaviour of a stall regulated variable speed wind turbine at low wind speed control region by using the closed loop scalar control with adjustable speed drive. The paper provided a description of each sub-model in the wind turbine system and described the scalar control of the induction machine. It was concluded that by using a constant voltage/frequency ratio of the generator's stator side control, the generator speed could be regulated and the generator torque could be controlled to ensure the power coefficient could be maintained close to its maximum value. 38 refs., 1 tab., 10 figs.

  13. Efficient monitoring of the blood-stage infection in a malaria rodent model by the rotating-crystal magneto-optical method

    Science.gov (United States)

    Orbán, Ágnes; Rebelo, Maria; Molnár, Petra; Albuquerque, Inês S.; Butykai, Adam; Kézsmárki, István

    2016-03-01

    Intense research efforts have been focused on the improvement of the efficiency and sensitivity of malaria diagnostics, especially in resource-limited settings for the detection of asymptomatic infections. Our recently developed magneto-optical (MO) method allows the accurate quantification of malaria pigment crystals (hemozoin) in blood by their magnetically induced rotation. First evaluations of the method using β-hematin crystals and in vitro P. falciparum cultures implied its potential for high-sensitivity malaria diagnosis. To further investigate this potential, here we study the performance of the method in monitoring the in vivo onset and progression of the blood-stage infection in a rodent malaria model. Our results show that the MO method can detect the first generation of intraerythrocytic P. berghei parasites 66-76 hours after sporozoite injection, demonstrating similar sensitivity to Giesma-stained light microscopy and exceeding that of flow cytometric techniques. Magneto-optical measurements performed during and after the treatment of P. berghei infections revealed that both the follow up under treatment and the detection of later reinfections are feasible with this new technique. The present study demonstrates that the MO method - besides being label and reagent-free, automated and rapid - has a high in vivo sensitivity and is ready for in-field evaluation.

  14. Rotating samples in FT-RAMAN spectrometers

    Science.gov (United States)

    De Paepe, A. T. G.; Dyke, J. M.; Hendra, P. J.; Langkilde, F. W.

    1997-11-01

    It is customary to rotate samples in Raman spectroscopy to avoid absorption or sample heating. In FT-Raman experiments the rotation is always shown (typically 30-60 rpm) because higher speeds are thought to generate noise in the spectra. In this article we show that more rapid rotation is possible. A tablet containing maleic acid and one made up of sub-millimetre silica particles with metoprolol succinate as active ingredient were rotated at different speeds, up to 6760 rpm. The FT-Raman spectra were recorded and studied. We conclude that it is perfectly acceptable to rotate samples up to 1500 rpm.

  15. Gas speed flow transducer

    Directory of Open Access Journals (Sweden)

    Godovaniouk V. N.

    2011-08-01

    Full Text Available The design of a gas speed flow transducer using the coupling of gas speed and heat streams within the transducer itself is proposed. To maintain the heat balance between two thermoresistors under gas stream at different temperatures, it provides energy consumption monitoring. The detailed combined planar technology for the transducer production is presented. The worked-out measurement procedure allows to make measurements in the temperature range. Information enough to organize production of cheap, reliable and precise gas speed flow transducers is given.

  16. Optical monitoring for power law fluids during spin coating.

    Science.gov (United States)

    Jardim, P L G; Michels, A F; Horowitz, F

    2012-01-30

    Optical monitoring is applied, in situ and in real time, to non-newtonian, power law fluids in the spin coating process. An analytical exact solution is presented for thickness evolution that well fits to most measurement data. As result, typical rheological parameters are obtained for several CMC (carboximetilcelullose) concentrations and rotation speeds. Optical monitoring thus precisely indicates applicability of the model to power law fluids under spin coating.

  17. Electronic Control Of Slow Rotations

    Science.gov (United States)

    Howard, David E.; Smith, Dennis A.

    1992-01-01

    Digital/analog circuit controls both angular position and speed of rotation of motor shaft with high precision. Locks angular position of motor to phase of rotation-command clock signal at binary submultiple of master clock signal. Circuit or modified version used to control precisely position and velocity of robotic manipulator, to control translation mechanism of crystal-growing furnace, to position hands of mechanical clock, or to control angular position and rate of rotation in any of large variety of rotating mechanisms.

  18. GE Smart Prep半自动监控软件的应用要点%Application Keypoints of GE Light Speed 8 Smart Prep Semiautomatic Monitoring Software

    Institute of Scientific and Technical Information of China (English)

    肖建明

    2011-01-01

    目的 探讨GE light speed 8 smart Prep技术在CT血管造影中的准确应用.方法 采用GE light speed 8 Smart Pmp软件对35例患者进行颅脑CTA检查.结果 总结出GE light speed 8运用smart prep 的技术要点.%Objective To investigate the application of the GE light speed 8 smart prep technique in CT angiography. Methods Used GE light speed 8 Smart Prep software to assist the check of cerebral CTA in 35 patients. Results Summarized the application keypoints of CE light speed 8 smart prep technique.

  19. Rotating electrical machines

    CERN Document Server

    Le Doeuff, René

    2013-01-01

    In this book a general matrix-based approach to modeling electrical machines is promulgated. The model uses instantaneous quantities for key variables and enables the user to easily take into account associations between rotating machines and static converters (such as in variable speed drives).   General equations of electromechanical energy conversion are established early in the treatment of the topic and then applied to synchronous, induction and DC machines. The primary characteristics of these machines are established for steady state behavior as well as for variable speed scenarios. I

  20. Sustainable Energy Solutions Task 2.0: Wind Turbine Reliability and Maintainability Enhancement through System-wide Structure Health Monitoring and Modifications to Rotating Components

    Energy Technology Data Exchange (ETDEWEB)

    Twomey, Janet M. [Wichita State Univ., Wichita, KS (United States)

    2010-04-30

    An evaluation of nondestructive structural health monitoring methods was completed with over 132 documents, 37 specifically about wind turbines, summarized into a technology matrix. This matrix lists the technology, what can be monitored with this technology, and gives a short summary of the key aspects of the technology and its application. Passive and active acoustic emission equipment from Physical Acoustics Corp. and Acellent Technologies have been evaluated and selected for use in experimental state loading and fatigue tests of composite wind turbine blade materials. Acoustic Emission (AE) and Active Ultrasonic Testing (AUT), were applied to composite coupons with both simulated and actual damage. The results found that, while composites are more complicated in nature, compared to metallic structures, an artificial neural network analysis could still be used to determine damage. For the AE system, the failure mode could be determined (i.e. fiber breakage, delamination, etc.). The Acellent system has been evaluated to work well with composite materials. A test-rig for reliability testing of the rotating components was constructed. The research on the types of bearings used in the wind turbines indicated that in most of the designs, the main bearings utilized to support the shaft are cylindrical roller bearings. The accelerated degradation testing of a population of bearings was performed. Vibration and acoustic emission data was collected and analyzed in order to identify a representative degradation signal for each bearing to identify the initiation of the degradation process in the bearings. Afterwards, the RMS of the vibration signal from degradation initiation up to the end of the useful life of the bearing was selected to predict the remaining useful life of the bearing. This step included fitting Autoregressive Moving Average (ARMA) models to the degradation signals and approximating the probability distribution function (PDF) of remaining useful life

  1. Effect of mold rotation on the bifilar electroslag remelting process

    Science.gov (United States)

    Shi, Xiao-fang; Chang, Li-zhong; Wang, Jian-jun

    2015-10-01

    A novel electroslag furnace with a rotating mold was fabricated, and the effects of mold rotational speed on the electroslag remelting process were investigated. The results showed that the chemical element distribution in ingots became uniform and that their compact density increased when the mold rotational speed was increased from 0 to 28 r/min. These results were attributed to a reasonable mold speed, which resulted in a uniform temperature in the slag pool and scattered the metal droplets randomly in the metal pool. However, an excessive rotational speed caused deterioration of the solidification structure. When the mold rotational speeds was increased from 0 to 28 r/min, the size of Al2O3 inclusions in the electroslag ingot decreased from 4.4 to 1.9 μm. But the excessive mold rotational speed would decrease the ability of the electroslag remelting to remove the inclusions. The remelting speed gradually increased, which resulted in reduced power consumption with increasing mold rotational speed. This effect was attributed to accelerated heat exchange between the consumable electrode and the molten slag, which resulted from mold rotation. Nevertheless, when the rotational speed reached 28 r/min, the remelting speed did not change because of limitations of metal heat conduction. Mold rotation also improved the surface quality of the ingots by promoting a uniform temperature distribution in the slag pool.

  2. Small Scale High Speed Turbomachinery

    Science.gov (United States)

    London, Adam P. (Inventor); Droppers, Lloyd J. (Inventor); Lehman, Matthew K. (Inventor); Mehra, Amitav (Inventor)

    2015-01-01

    A small scale, high speed turbomachine is described, as well as a process for manufacturing the turbomachine. The turbomachine is manufactured by diffusion bonding stacked sheets of metal foil, each of which has been pre-formed to correspond to a cross section of the turbomachine structure. The turbomachines include rotating elements as well as static structures. Using this process, turbomachines may be manufactured with rotating elements that have outer diameters of less than four inches in size, and/or blading heights of less than 0.1 inches. The rotating elements of the turbomachines are capable of rotating at speeds in excess of 150 feet per second. In addition, cooling features may be added internally to blading to facilitate cooling in high temperature operations.

  3. Locating air quality monitoring station using wind impact area diagram.

    Science.gov (United States)

    George, K V; Verma, P; Devotta, S

    2008-10-01

    In this study a new methodology is suggested to approximate the impact area downwind of an air pollution source, where air quality monitoring can be carried out to capture the maximum pollutant concentration. Hourly wind speed for a given month is grouped in to different wind speed ranges and the distance of pollutant travel is approximated from the average wind speed of that wind speed range. Since change in wind direction causes the impact distance to rotate, its rotation is approximated by the SD of wind direction change. Using this approach, area or region down wind of a source is determined and plotted. The pattern of monthly change of wind is better represented by the new type of diagram as compared to the wind rose diagram.

  4. Rotating ice blocks

    Science.gov (United States)

    Dorbolo, Stephane; Adami, Nicolas; Grasp Team

    2014-11-01

    The motion of ice discs released at the surface of a thermalized bath was investigated. As observed in some rare events in the Nature, the discs start spinning spontaneously. The motor of this motion is the cooling of the water close to the ice disc. As the density of water is maximum at 4°C, a downwards flow is generated from the surface of the ice block to the bottom. This flow generates the rotation of the disc. The speed of rotation depends on the mass of the ice disc and on the temperature of the bath. A model has been constructed to study the influence of the temperature of the bath. Finally, ice discs were put on a metallic plate. Again, a spontaneous rotation was observed. FNRS is thanked for financial support.

  5. A influência do perfil da ferramenta e velocidade de rotação na soldagem a ponto por fricção e mistura mecânica da liga AA 6181-T4 The influence of tool geometry and rotational speed on friction stir spot welding of aluminum alloy AA- 6181-T4

    Directory of Open Access Journals (Sweden)

    Fabiano Dornelles Ramos

    2012-06-01

    .Friction Stir Spot Welding is a process that occurs in solid state with high energy efficiency, low manufacture costs and environmentally friendly. These friction processes are an alternative to conventional processes like resistance spot welding, riveting and clinching. The absent of a fusion zone on these processes avoid defects like porosity, bubbles, recess, inclusions and undesired microstructures, that appears very often on weld metal and heat affected zones of fusion weld processes. The Friction Stir Spot Welding process (SPFMM- FSSW consists in a rotating tool (pin and shoulder combined that penetrates the overlap joint stirring the material and consolidating the joint. The contact of adjacent region of the tool generates the friction heating and, this heating, promotes the plasticization of the material that, at the same time, is stirred by the tool pin leaving a stir zone and a keyhole after process is finished. The aim of the present work is to evaluate the influence of tool profile and rotational speed on the mechanical and metallurgical behavior of friction stir spot welded AA6181-T4 aluminum alloy. The metallurgical characterization was performed through optical microscopy, stereoscope and scanning electron microscopy. The mechanical testing was made trough shear test, microhardness profile and torque/forces monitoring during the process. It was possible to observe a tendency of increasing in mechanical strength of the joint with applying higher rotational speed values. The utilization of different tool profiles presented significant differences, but, with much reliance of the rotational speed, pin and shoulder combination.

  6. Rotating flow

    CERN Document Server

    Childs, Peter R N

    2010-01-01

    Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics

  7. Numerical study on thermodynamic characteristics of rotational supercavitating evaporator

    Science.gov (United States)

    Li, Q.; Zheng, Z. Y.; Li, F. C.; Kulagin, V. A.

    2016-05-01

    Rotational Supercavitating Evaporator (RSCE) has been proposed as a new technology for seawater desalination. However, thermodynamic characteristics of rotational supercavitation are still vacant. In this paper, numerical simulations are conducted on the supercavitating flows around a 3D rotating blade of RSCE with different rotational speeds and extraction pressures. Energy effect is taken into consideration in the simulation and thermodynamic characteristics of rotational supercavitation are obtained. Rotational supercavitation has a larger convective heat transfer coefficient than the boiling on a heated wall.

  8. A rotating Michelson interferometer from the co-rotating point of view

    Science.gov (United States)

    Maraner, Paolo

    2016-06-01

    The phase shift induced by a uniform rotation in a Michelson interferometer is re-derived in the geometrical framework of the coordinate-free formalism of general relativity from the co-rotating point of view. The effect is second order in the ratio of the interferometer's speed to the speed of light and further suppressed by the ratio of the length of the interferometer's arms to the radius of rotation. The relation of the effect to gravitational time dilation is discussed.

  9. Rotating Wavepackets

    Science.gov (United States)

    Lekner, John

    2008-01-01

    Any free-particle wavepacket solution of Schrodinger's equation can be converted by differentiations to wavepackets rotating about the original direction of motion. The angular momentum component along the motion associated with this rotation is an integral multiple of [h-bar]. It is an "intrinsic" angular momentum: independent of origin and…

  10. Rotational elasticity

    Science.gov (United States)

    Vassiliev, Dmitri

    2017-04-01

    We consider an infinite three-dimensional elastic continuum whose material points experience no displacements, only rotations. This framework is a special case of the Cosserat theory of elasticity. Rotations of material points are described mathematically by attaching to each geometric point an orthonormal basis that gives a field of orthonormal bases called the coframe. As the dynamical variables (unknowns) of our theory, we choose the coframe and a density. We write down the general dynamic variational functional for our rotational theory of elasticity, assuming our material to be physically linear but the kinematic model geometrically nonlinear. Allowing geometric nonlinearity is natural when dealing with rotations because rotations in dimension three are inherently nonlinear (rotations about different axes do not commute) and because there is no reason to exclude from our study large rotations such as full turns. The main result of the talk is an explicit construction of a class of time-dependent solutions that we call plane wave solutions; these are travelling waves of rotations. The existence of such explicit closed-form solutions is a non-trivial fact given that our system of Euler-Lagrange equations is highly nonlinear. We also consider a special case of our rotational theory of elasticity which in the stationary setting (harmonic time dependence and arbitrary dependence on spatial coordinates) turns out to be equivalent to a pair of massless Dirac equations. The talk is based on the paper [1]. [1] C.G.Boehmer, R.J.Downes and D.Vassiliev, Rotational elasticity, Quarterly Journal of Mechanics and Applied Mathematics, 2011, vol. 64, p. 415-439. The paper is a heavily revised version of preprint https://arxiv.org/abs/1008.3833

  11. Overview on earthquake monitoring and early warning system for high-speed Railway (Shinkansen) in Japan%日本新干线地震监测与预警系统

    Institute of Scientific and Technical Information of China (English)

    宋晋东; 李山有; 马强

    2012-01-01

    地震是一种对高速铁路行车安全危害极大的自然灾害,为了减轻地震对高速铁路造成的灾害,建设高速铁路地震监测与预警系统是一项行之有效的手段.详细介绍了较为成熟的日本新干线地震监测与预警系统的发展历史、系统组成、紧急处置流程、报警方式、震源参数与紧急处置范围的确定方法,以及该系统在2011年3月11日东日本大地震中的紧急处置过程,旨在为中国高速铁路地震监测与预警系统的研究与建设提供参考和借鉴.%Earthquake is a kind of natural disaster which has greatest threat to high - speed railway operation. Earthquake monitoring and early warning system is one of the effective ways to mitigate earthquake hazards for high - speed railway. This paper summarizes the development history, composition and emergency processing, type of a-larm and the determination method for the source parameters and the warning area potentially subject to damage of the earthquake monitoring and early warning system for the high-speed railway ( Shinkansen) in Japan that has been developed sophisticatedly, and presents the case of the 2011 Tonihon earthquake, so as to give necessary background and a reference to the research and construction of earthquake monitoring and early warning system for the high - speed railway in China.

  12. FLOW PAST TWO ROTATING CIRCULAR CYLINDERS IN A SIDE-BY-SIDE ARRANGEMENT

    Institute of Scientific and Technical Information of China (English)

    GUO Xiao-hui; LIN Jian-zhong; TU Cheng-xu; WANG Hao-li

    2009-01-01

    Measurements were performed using Particle Image Velocimetry (PIV) to analyze the modification of flow by the combined effects of the rotation and the Reynolds number on the flow past two rotating circular cylinders in a side-by-side-arrangement at a range of , (α is the rotational speed) at one gap spacing of (T and d are the distance between the centers of two cylinders and the cylinder diameter, respectively). A new Immersed-Lattice Boltzmann Method (ILBM) scheme was used to study the effect of the gap spacing on the flow. The results show that the vortex shedding is suppressed as rotational speed increases. The flow reaches a steady state when the vortex shedding for both cylinders is completely suppressed at critical rotational speed. As the rotational speed further increases, the separation phenomenon in the boundary layers disappears at the attachment rotational speed. The critical rotational speed and attachment rotational speed become small as Reynolds number increases. The absolute rotational speed of cylinders should be large at same critical rotational speed and attachment rotational speed in the case of large Reynolds number. The gap spacing has an important role in changing the pattern of vortex shedding. It is very different in the mechanism of vortex shedding suppression for the flows around two rotating cylinders and single rotating cylinder.

  13. Advances in Rotational Seismic Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Pierson, Robert [Applied Technology Associates, Albuquerque, NM (United States); Laughlin, Darren [Applied Technology Associates, Albuquerque, NM (United States); Brune, Robert [Applied Technology Associates, Albuquerque, NM (United States)

    2016-10-19

    Rotational motion is increasingly understood to be a significant part of seismic wave motion. Rotations can be important in earthquake strong motion and in Induced Seismicity Monitoring. Rotational seismic data can also enable shear selectivity and improve wavefield sampling for vertical geophones in 3D surveys, among other applications. However, sensor technology has been a limiting factor to date. The US Department of Energy (DOE) and Applied Technology Associates (ATA) are funding a multi-year project that is now entering Phase 2 to develop and deploy a new generation of rotational sensors for validation of rotational seismic applications. Initial focus is on induced seismicity monitoring, particularly for Enhanced Geothermal Systems (EGS) with fracturing. The sensors employ Magnetohydrodynamic (MHD) principles with broadband response, improved noise floors, robustness, and repeatability. This paper presents a summary of Phase 1 results and Phase 2 status.

  14. High speed flywheel

    Science.gov (United States)

    McGrath, Stephen V.

    1991-01-01

    A flywheel for operation at high speeds utilizes two or more ringlike coments arranged in a spaced concentric relationship for rotation about an axis and an expansion device interposed between the components for accommodating radial growth of the components resulting from flywheel operation. The expansion device engages both of the ringlike components, and the structure of the expansion device ensures that it maintains its engagement with the components. In addition to its expansion-accommodating capacity, the expansion device also maintains flywheel stiffness during flywheel operation.

  15. Design of intelligent monitoring and controlling system of high-speed punching machine status%高速冲压设备状态智能监控系统设计

    Institute of Scientific and Technical Information of China (English)

    黄泽森; 戴星; 汤世友

    2009-01-01

    Working principle and key technology of the intelligent monitoring and controlling system of the highspeed punching machine are introduced, which consisted of piezoelectric impact pressure sensor, eddy-current testing sensor, intelligent monitoring and controlling instruments, nonconforming high-speed separation mechanism. Experiment shows that the system can monitor and control the status of the high-speed punching machine effectively. The separation of nonconforming steel ball is achieved. The steel ball pass rate is above 98 %. The system is stable and reliable.%介绍了由压电式冲击压力传感器、涡流探伤传感器、智能监控仪、不合格品高速分选机构等组成的高速冲压设备状态智能监控系统的工作原理及其关键技术.试验证明:该系统能有效监控高速冲压设备状态和实现对不合格钢球毛胚的分选,毛胚合格率可达98%以上.该智能监控系统运行稳定、可靠.

  16. Speed mathematics

    CERN Document Server

    Handley, Bill

    2012-01-01

    This new, revised edition of the bestselling Speed Mathematics features new chapters on memorising numbers and general information, calculating statistics and compound interest, square roots, logarithms and easy trig calculations. Written so anyone can understand, this book teaches simple strategies that will enable readers to make lightning-quick calculations. People who excel at mathematics use better strategies than the rest of us; they are not necessarily more intelligent. With Speed Mathematics you'll discover methods to make maths easy and fun. This book is perfect for stud

  17. Earth rotation and geodynamics

    Science.gov (United States)

    Bogusz, Janusz; Brzezinski, Aleksander; Kosek, Wieslaw; Nastula, Jolanta

    2015-12-01

    This paper presents the summary of research activities carried out in Poland in 2011-2014 in the field of Earth rotation and geodynamics by several Polish research institutions. It contains a summary of works on Earth rotation, including evaluation and prediction of its parameters and analysis of the related excitation data as well as research on associated geodynamic phenomena such as geocentre motion, global sea level change and hydrological processes. The second part of the paper deals with monitoring of geodynamic phenomena. It contains analysis of geodynamic networks of local, and regional scale using space (GNSS and SLR) techniques, Earth tides monitoring with gravimeters and water-tube hydrostatic clinometer, and the determination of secular variation of the Earth' magnetic field.

  18. The effect of rotations on Michelson interferometers

    Science.gov (United States)

    Maraner, Paolo

    2014-11-01

    In the contest of the special theory of relativity, it is shown that uniform rotations induce a phase shift in Michelson interferometers. The effect is second order in the ratio of the interferometer's speed to the speed of light, further suppressed by the ratio of the interferometer's arms length to the radius of rotation and depends on the interferometer's position in the co-rotating frame. The magnitude of the phase shift is just beyond the sensitivity of turntable rotated optical resonators used in present tests of Lorentz invariance. It grows significantly large in Earth's rotated kilometer-scale Fabry-Perot enhanced interferometric gravitational-wave detectors where it appears as a constant bias. The effect can provide the means of sensing center and radius of rotations.

  19. Polygons on a rotating fluid surface

    DEFF Research Database (Denmark)

    Jansson, Thomas R.N.; Haspang, Martin P.; Jensen, Kåre H.;

    2006-01-01

    rotating rigidly with a speed different from that of the plate. With water, we have observed polygons with up to 6 corners. It has been known for many years that such flows are prone to symmetry breaking, but apparently the polygonal surface shapes have never been observed. The creation of rotating...

  20. Bioprocess kinetics in a horizontal rotating tubular bioreactor.

    Science.gov (United States)

    Ivancić, M; Santek, B; Novak, S; Horvat, P; Marić, V

    2004-04-01

    A horizontal rotating tubular bioreactor (HRTB) is a plug flow bioreactor whose interior is provided with O-ring-shaped partition walls that serve as carriers for microbial biomass. During this investigation, microbial biomass was grown in suspension and on the bioreactor inner surface as a microbial biofilm with average mass that was considerably higher than suspended biomass. The dynamics of bioprocess in HRTB was studied by different combinations of process parameters (bioreactor rotation speed and mean residence time) and it was monitored by withdrawing the samples from five positions along the bioreactor. During this investigation it was also observed that mean residence time had a more pronounced effect on the bioprocess dynamics than bioreactor rotation speed. For the description of bioprocess kinetics in HRTB an unstructured kinetic model was established that defines biomass growth, product formations and substrate consumption rate by using a modified Monod (Levenspiel) model. This kinetic model defines changes in suspension and in microbial biofilm, and it shows relatively good agreement with experimental data.

  1. Propulsion Health Monitoring of a Turbine Engine Disk Using Spin Test Data

    Science.gov (United States)

    Abdul-Aziz, Ali; Woike, Mark R.; Oza, Nikunj; Matthews, Bryan; Baaklini, George Y.

    2010-01-01

    This paper considers data collected from an experimental study using high frequency capacitive sensor technology to capture blade tip clearance and tip timing measurements in a rotating turbine engine-like-disk-to predict the disk faults and assess its structural integrity. The experimental results collected at a range of rotational speeds from tests conducted at the NASA Glenn Research Center s Rotordynamics Laboratory are evaluated using multiple data-driven anomaly detection techniques to identify abnormalities in the disk. Further, this study presents a select evaluation of an online health monitoring scheme of a rotating disk using high caliber sensors and test the capability of the in-house spin system.

  2. Universal computer vision system for monitoring the main parameters of wind turbines

    Directory of Open Access Journals (Sweden)

    Korzhavin Sergey

    2016-01-01

    Full Text Available The article presents universal autonomous system of computer vision to monitor the operation of wind turbines. The proposed system allows to estimate the rotational speed and the relative position deviation of the wind turbine. We present a universal method for determining the rotation of wind turbines of various shapes and structures. All obtained data are saved in the database. The presented method was tested at the Territory of Non-traditional Renewable Energy Sources of Ural Federal University Experimental wind turbines is produced by “Scientific and Production Association of automatics named after academician N.A. Semikhatov”. Results show the efficiency of the proposed system and the ability to determine main parameters such as the rotational speed, accuracy and quickness of orientation. The proposed solution is to assume that, in most cases a rotating and central parts of the wind turbine can be allocated different color. The color change of wind blade should not affect the system performance.

  3. Automatic speed control of highway traffic

    Science.gov (United States)

    Klingman, E. E.

    1973-01-01

    Vehicle control system monitors all vehicles in its range, and automatically slows down speeding vehicles by activating governor in vehicle. System determines only maximum speed; speeds below maximum are controlled by vehicle operator. Loss of transmitted signal or activation of emergency over-ride will open fuel line and return control to operator.

  4. Dynamic behaviour of a rotating cracked beam

    Science.gov (United States)

    Yashar, Ahmed; Ghandchi-Tehrani, Maryam; Ferguson, Neil

    2016-09-01

    This paper presents a new approach to investigate and analyse the vibrational behaviour of cracked rotating cantilever beams, which can for example represent helicopter or wind turbine blades. The analytical Hamiltonian method is used in modelling the rotating beam and two numerical methods, the Rayleigh-Ritz and FEM, are used to study the natural frequencies and the mode shapes of the intact rotating beams. Subsequently, a crack is introduced into the FE model and simulations are performed to identify the modal characteristics for an open cracked rotating beam. The effect of various parameters such as non-dimensional rotating speed, hub ratio and slenderness ratio are investigated for both the intact and the cracked rotating beam, and in both directions of chordwise and flapwise motion. The veering phenomena in the natural frequencies as a function of the rotational speed and the buckling speed are considered with respect to the slenderness ratio. In addition, the mode shapes obtained for the flapwise vibration are compared using the modal assurance criterion (MAC). Finally, a new three dimensional design chart is produced, showing the effect of crack location and depth on the natural frequencies of the rotating beam. This chart will be subsequently important in identifying crack defects in rotating blades.

  5. Influence of Rotation of Steady Speed Table on Orientation Stability of Servo Table in Linear Accelerating table%线加速度台中稳速台转动对随动台定位稳定性的影响

    Institute of Scientific and Technical Information of China (English)

    高扬; 唐声权; 张新磊; 吴华阳

    2012-01-01

    针对线加速度台用于加速度计测试时,随动台定位受稳速台旋转干扰的现象进行了分析,提出被测设备质量要在负载允许范围内,使设备质心尽可能靠近随动台回转中心,并对其配平,以使稳速台转动带来的干扰力矩大大降低,保证测试中随动台的定位准确度及稳定性.%The phenomenon that servo table positioning interfered by steady speed table rotating was analysis among linear accelerating table on testing accuracy of accelerometer. The weight of equipment is brought forward to be within the allowable range, as far as possible to make the centroid of equipment close to the servo table rotary center, and use other loads to balance it if required. It has reduced disturbance torque caused by rotation of steady speed table and improved the stability of the test axis positioning, and ensured positioning accuracy to fulfil the test.

  6. Energy harvester for rotating environments using offset pendulum and nonlinear dynamics

    Science.gov (United States)

    Roundy, Shad; Tola, Jeffry

    2014-10-01

    We present an energy harvester for environments that rotate through the Earth’s gravitational field. Example applications include shafts connected to motors, axles, propellers, fans, and wheels or tires. Our approach uses the unique dynamics of an offset pendulum along with a nonlinear bistable restoring spring to improve the operational bandwidth of the system. Depending on the speed of the rotating environment, the system can act as a bistable oscillator, monostable stiffening oscillator, or linear oscillator. We apply our approach to a tire pressure monitoring system mounted on a car rim. Simulation and experimental test results show that the prototype generator is capable of directly powering an RF transmission every 60 s or less over a speed range of 10 to 155 kph.

  7. Modal Analysis in Periodic, Time-Varying Systems with emphasis to the Coupling between Flexible Rotating Beams and Non-Rotating Flexible Structures

    DEFF Research Database (Denmark)

    Saracho, C. M.; Santos, Ilmar

    2003-01-01

    The analysis of dynamical response of a system built by a non-rotating structure coupled to flexible rotating beams is the purpose of this work. The effect of rotational speed upon the beam natural frequencies is well-known, so that an increase in the angular speeds leads to an increase in beam...

  8. Performance monitoring and quality evaluation of high speed railway based on LTE signaling%基于LTE信令软采的高铁性能监控及质量评估

    Institute of Scientific and Technical Information of China (English)

    葛强

    2016-01-01

    湖北移动针对区域内高铁的评估优化需求日益增长,而传统测试手段时效长、成本高、用户覆盖与质量感知难以反馈,创新的利用软采成本低、海量高铁用户信息的特性,成功建立基于用户移动轨迹行为的“高铁用户识别模型”和“用户位置定位技术”,全面实现高铁网络性能监控与评估,并可深度输出高铁覆盖、切换、干扰等网络问题,结合用户多信息关联分析法快速定位问题的原因,全面高效助力于高铁网络优化。%With the high demand of high-speed railway network evaluation, the traditional methods means long time, high cost, and diffi cult to feedback. Hubei Mobile uses the characteristics of low cost and magnanimous user information of LTE signaling, successfully build up the high speed rail user identifi cation model and user locating technology. Performance monitoring and network evaluation of high speed railway network by LTE signaling is now capable, which also can show network problems directly, deeply help us in high-speed railway network optimization.

  9. Single-electrode-based rotating triboelectric nanogenerator for harvesting energy from tires.

    Science.gov (United States)

    Zhang, Hulin; Yang, Ya; Zhong, Xiandai; Su, Yuanjie; Zhou, Yusheng; Hu, Chenguo; Wang, Zhong Lin

    2014-01-28

    Rotational energy is abundant and widely available in our living environment. Harvesting ambient rotational energy has attracted great attention. In this work, we report a single-electrode-based rotating triboelectric nanogenerator (SR-TENG) for converting rotational energy into electric energy. The unique advantage of introducing the single-electrode TENG is to overcome the difficulty in making the connection in harvesting rotational energy such as from a moving and rotating tire/wheel. The fabricated device consists of a rotary acrylic disc with polytetrafluoroethylene (PTFE) blades and an Al electrode fixed on the base. The systematical experiments and theoretical simulations indicate that the asymmetric SR-TENGs exhibit much better output performances than those of the symmetric TENGs at the same rotation rates. The asymmetric SR-TENG with seven PTFE units at the rotation rate of 800 r/min can deliver a maximal output voltage of 55 V and a corresponding output power of 30 μW on a load of 100 MΩ, which can directly light up tens of red light-emitting diodes. The SR-TENG has been utilized to harvest mechanical energy from rotational motion of a bicycle wheel. Furthermore, we demonstrated that the SR-TENG can be applied to scavenge wind energy and as a self-powered wind speed sensor with a sensitivity of about 0.83 V/(m/s). This study further expands the operation principle of a single-electrode-based TENG and many potential applications of TENGs for scavenging ambient rotational energy and as a self-powered environment monitoring sensor.

  10. Research on Gale Monitoring & Early Warning System of High-speed Railway%高速铁路大风监测预警系统的研究

    Institute of Scientific and Technical Information of China (English)

    龚炯; 王鹏

    2012-01-01

    文章针对侧风对高速铁路列车行进的影响,在研究分析国内外铁路大风监测安全系统的基础上,以远程监控单元和地理信息系统为核心,给出了高速铁路大风监测与预警系统的设计方案。该方案基于现场层、远程终端层、中心处理层和应用层的4层结构,建立了以远程终端监控单元和地理信息系统为核心的软硬件架构,并分析了二者的功能和相应的设计方法。%As the cross-wind would severely endanger the operation of the high-speed railway train, based on the research of the domestic and overseas railway gail monitoring system, the paper summarizes the general structure of the anti-gale early warning system. With remote monitoring unit and GIS at the core, the paper designs a gale monitoring and pre warning system for high-speed railway. Based on four-layer architecture (work layer, remote terminal layer, central pro- cessing layer,application layer), the software and hardware architecture of this system takes the remote terminal monito- ring unit and GIS as the core, and the paper analyses both functions and design methods.

  11. A method to deconvolve stellar rotational velocities

    CERN Document Server

    Cure, Michel; Cassetti, Julia; Christen, Alejandra

    2014-01-01

    Rotational speed is an important physical parameter of stars and knowing the distribution of stellar rotational velocities is essential for the understanding stellar evolution. However, it cannot be measured directly but the convolution of the rotational speed and the sine of the inclination angle, $v \\sin i$. We developed a method to deconvolve this inverse problem and obtain the cumulative distribution function (CDF) for stellar rotational velocities extending the work of Chandrasekhar & M\\"unch (1950). This method is applied a) to theoretical synthetic data recovering the original velocity distribution with very small error; b) to a sample of about 12.000 field main--sequence stars, corroborating that the velocity distribution function is non--Maxwellian, but is better described by distributions based on the concept of maximum entropy, such as Tsallis or Kaniadakis distribution functions. This is a very robust and novel method that deconvolve the rotational velocity cumulative distribution function fro...

  12. EXPERIMENTAL STUDY OF A ROTATING PACKED BED DISTILLATION COLUMN

    OpenAIRE

    Nascimento, JVS; Ravagnani, TMK; Pereira, JAFR

    2009-01-01

    The purpose of this work was to study the mass transfer performance of rotating packed beds applying the "Higee" process. The operations were carried out with the n-hexane/n-heptane distilling system at atmospheric pressure and under total reflux conditions. The rotating speed could be varied between 300 and 2500 rpm, which provided centrifugal forces from 5 to 316 times the Earth's gravity. The effects of concentration, vapor velocity, rotating speed and packing type (two different Raschig r...

  13. Experimental study of a rotating packed bed distillation column

    OpenAIRE

    Nascimento,J. V. S.; Ravagnani,T. M. K.; Pereira,J. A. F. R.

    2009-01-01

    The purpose of this work was to study the mass transfer performance of rotating packed beds applying the "Higee" process. The operations were carried out with the n-hexane/n-heptane distilling system at atmospheric pressure and under total reflux conditions. The rotating speed could be varied between 300 and 2500 rpm, which provided centrifugal forces from 5 to 316 times the Earth's gravity. The effects of concentration, vapor velocity, rotating speed and packing type (two different Raschig r...

  14. On the role of nonsynchronous rotating damping in rotordynamics

    OpenAIRE

    Giancarlo Genta; Eugenio Brusa

    2000-01-01

    Nonsynchronous rotating damping, i.e. energy dissipations occurring in elements rotating at a speed different from the spin speed of a rotor, can have substantial effects on the dynamic behaviour and above all on the stability of rotating systems.The free whirling and unbalance response for systems with nonsynchronous damping are studied using Jeffcott rotor model. The system parameters affecting stability are identified and the threshold of instability is computed. A general model for a mult...

  15. Rotational Efficiency of Photo-Driven Archimedes Screws for Micropumps

    Directory of Open Access Journals (Sweden)

    Chih-Lang Lin

    2015-06-01

    Full Text Available In this study, we characterized the rotational efficiency of the photo-driven Archimedes screw. The micron-sized Archimedes screws were fabricated using the two-photon polymerization technique. Free-floating screws trapped by optical tweezers align in the laser irradiation direction and rotate spontaneously. The influences of the screw pitch and the number of screw blades have been investigated in our previous studies. In this paper, the blade thickness and the central rod of the screw were further investigated. The experimental results indicate that the blade thickness contributes to rotational stability, but not to rotational speed, and that the central rod stabilizes the rotating screw but is not conducive to rotational speed. Finally, the effect of the numerical aperture (NA of the optical tweezers was investigated through a demonstration. The NA is inversely proportional to the rotational speed.

  16. Rotation sensing with trapped ions

    CERN Document Server

    Campbell, W C

    2016-01-01

    We present a protocol for using trapped ions to measure rotations via matter-wave Sagnac interferometry. The trap allows the interferometer to enclose a large area in a compact apparatus through repeated round-trips in a Sagnac geometry. We show how a uniform magnetic field can be used to close the interferometer over a large dynamic range in rotation speed and measurement bandwidth without losing contrast. Since this technique does not require the ions to be confined in the Lamb-Dicke regime, thermal states with many phonons should be sufficient for operation.

  17. Apparent speed increases at low luminance

    OpenAIRE

    Vaziri-Pashkam, Maryam; Cavanagh, Patrick

    2008-01-01

    To investigate the effect of luminance on apparent speed, subjects adjusted the speed of a low-luminance rotating grating (0.31 cd/m2) to match that of a high-luminance one (1260 cd/m2). Above 4 Hz, subjects overestimated the speed of the low-luminance grating. This overestimation increased as a function of temporal rate and reached 30% around 10 Hz temporal rates. The speed overestimation became significant once the lower luminance was 2.4 log units lower than the high luminance comparison. ...

  18. Containment of the western corn rootworm Diabrotica v.virgifera: continued successful management 2008 in southern Switzerland by monitoring and crop rotation.

    Science.gov (United States)

    Hummel, Hans E; Bertossa, M

    2009-01-01

    Diabrotica virgifera virgifera LeConte (Col.: Chrysomelidae), known as western corn rootworm (WCR) and endemic in North America, invaded Europe about two decades ago. Various unsuccessful attempts have been made to eradicate it from the Old World. Management with a variety of strategies is the option now remaining. WCR management in Southern Switzerland by a unique containment approach has been practiced successfully since 2003 using biotechnical means. Without any chemical pesticides or GMO input, the Swiss government mandated adherence to strict crop rotation. In addition to the economic benefits of this relatively simple approach, the environment was saved a considerable burden of pesticide applications. Other countries are invited to follow this example of sustainable pest management.

  19. Rotational States of Methyl Radical Monitored by EPR Line Shape of Matrix-Isolated CH3 in CO2 and N2O Solids

    Science.gov (United States)

    Dmitriev, Yu. A.; Melnikov, V. D.; Zelenetckii, I. A.; Benetis, N. P.

    2016-12-01

    Methyl radicals, CH3, were trapped in matrices of solid CO2 and N2O by condensing the methyl along with the matrix constituents from the gas phase. The obtained EPR spectra were analyzed using EasySpin and/ or SimFonia simulation software and ab-initio computed quantum-chemistry parameters. We focus on two distinguished features of the spectra: the temperature-dependent linewidth anisotropy and the origin of the weak satellite doublets. The low-temperature spectral analysis of the satellites was based on the coupled representation of the three proton spins of CH3 and a recently obtained parameterization of the spin Hamiltonian based on one nuclear quartet and two doublets within the D3 group. These features were closely correlated to the state of rotation of the trapped radical.

  20. 基于纳米晶软磁合金的转矩、转速和转角多功能传感器研究%Research on a Multifunction Sensor Based on Nanocrystalline Soft Magnetic Alloy for Measuring Torque, Rotational Speed and Angular Displacement

    Institute of Scientific and Technical Information of China (English)

    石延平; 周庆贵; 臧勇

    2012-01-01

    To improve the versatility of sensor, a new non-contact sensor to measure angle, rotational speed and torque at the same time was discussed. First, the structure and principle based on magneto - elastic effect of nanocrystalline soft magnetic alloy were presented. Second its output mathematical model and sensitivity formula were derived. Finally a measuring experiment was made at 25 ~100℃ temperature range , 0~450N · m torque range and 500~3525r/min rotational speed range. The testing results are that the sensor's temperature drift is as 0. 002 03% F. S/℃ for 25℃ , its maximum linearity 0. 81% F. S, repeatability error 0. 50% F. S, hysteresis error 0. 85% F. S and rotational speed maximum relative error 0. 70%. The experimental results also show the sensor's sensitivity is as 1. 26mV/N · m and measurement precision is as 1. 0%, so it can be used for general engineering applications.%为提高传感器的多功能性,对一种可同时测量转角、转速和转矩的非接触式传感器进行了研究.首先,论述了传感器的结构和基于纳米晶软磁合金压磁效应的测量原理,然后推导出传感器的输出数学模型与灵敏度表达式.最后,在25~100℃温度范围、0~450N·m转矩范围及500~3525 r/min范围内进行试验,得出相对于25℃的零点温度漂移为0.00203%/℃(满量程),满量程最大线性度、重复度及迟滞静态误差分别为0.81%、0.50%、0.85%,转速最大相对误差为0.70%.试验数据还显示,该传感器的测量灵敏度为1.26mV/N·m,精度达到1.0%,对于一般工程应用是可行的.

  1. Low speed phaselock speed control system. [for brushless dc motor

    Science.gov (United States)

    Fulcher, R. W.; Sudey, J. (Inventor)

    1975-01-01

    A motor speed control system for an electronically commutated brushless dc motor is provided which includes a phaselock loop with bidirectional torque control for locking the frequency output of a high density encoder, responsive to actual speed conditions, to a reference frequency signal, corresponding to the desired speed. The system includes a phase comparator, which produces an output in accordance with the difference in phase between the reference and encoder frequency signals, and an integrator-digital-to-analog converter unit, which converts the comparator output into an analog error signal voltage. Compensation circuitry, including a biasing means, is provided to convert the analog error signal voltage to a bidirectional error signal voltage which is utilized by an absolute value amplifier, rotational decoder, power amplifier-commutators, and an arrangement of commutation circuitry.

  2. Broadband Rotational Spectroscopy

    Science.gov (United States)

    Pate, Brooks

    2014-06-01

    The past decade has seen several major technology advances in electronics operating at microwave frequencies making it possible to develop a new generation of spectrometers for molecular rotational spectroscopy. High-speed digital electronics, both arbitrary waveform generators and digitizers, continue on a Moore's Law-like development cycle that started around 1993 with device bandwidth doubling about every 36 months. These enabling technologies were the key to designing chirped-pulse Fourier transform microwave (CP-FTMW) spectrometers which offer significant sensitivity enhancements for broadband spectrum acquisition in molecular rotational spectroscopy. A special feature of the chirped-pulse spectrometer design is that it is easily implemented at low frequency (below 8 GHz) where Balle-Flygare type spectrometers with Fabry-Perot cavity designs become technologically challenging due to the mirror size requirements. The capabilities of CP-FTMW spectrometers for studies of molecular structure will be illustrated by the collaborative research effort we have been a part of to determine the structures of water clusters - a project which has identified clusters up to the pentadecamer. A second technology trend that impacts molecular rotational spectroscopy is the development of high power, solid state sources in the mm-wave/THz regions. Results from the field of mm-wave chirped-pulse Fourier transform spectroscopy will be described with an emphasis on new problems in chemical dynamics and analytical chemistry that these methods can tackle. The third (and potentially most important) technological trend is the reduction of microwave components to chip level using monolithic microwave integrated circuits (MMIC) - a technology driven by an enormous mass market in communications. Some recent advances in rotational spectrometer designs that incorporate low-cost components will be highlighted. The challenge to the high-resolution spectroscopy community - as posed by Frank De

  3. The effect of rotations on Michelson interferometers

    Energy Technology Data Exchange (ETDEWEB)

    Maraner, Paolo, E-mail: pmaraner@unibz.it

    2014-11-15

    In the contest of the special theory of relativity, it is shown that uniform rotations induce a phase shift in Michelson interferometers. The effect is second order in the ratio of the interferometer’s speed to the speed of light, further suppressed by the ratio of the interferometer’s arms length to the radius of rotation and depends on the interferometer’s position in the co-rotating frame. The magnitude of the phase shift is just beyond the sensitivity of turntable rotated optical resonators used in present tests of Lorentz invariance. It grows significantly large in Earth’s rotated kilometer-scale Fabry–Perot enhanced interferometric gravitational-wave detectors where it appears as a constant bias. The effect can provide the means of sensing center and radius of rotations. - Highlights: • Rotations induce a phase shift in Michelson interferometers. • Earth’s rotation induces a constant bias in Michelson interferometers. • Michelson interferometers can be used to sense center and radius of rotations.

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

    OpenAIRE

    Cristian G. Rodriguez; Borja Mateos-Prieto; Eduard Egusquiza

    2014-01-01

    Current trends in design of pump-turbines have led into higher rotor-stator interaction (RSI) loads over impeller-runner. These dynamic loads are of special interest having produced catastrophic failures in pump-turbines. Determining RSI characteristics facilitates the proposal of actions that will prevent these failures. Pressure measurements all around the perimeter of the impeller-runner are appropriate to monitor and detect RSI characteristics. Unfortunately most installed pump-turbines a...

  5. COMMENT: Evaluation of a proposed test of the weak equivalence principle using Earth-orbiting bodies in high-speed co-rotation: re-establishing the physical bases

    Science.gov (United States)

    Nobili, A. M.; Bramanti, D.; Polacco, E.; Catastini, G.; Anselmi, A.; Portigliotti, S.; Lenti, A.; di Giamberardino, P.; Monaco, S.; Ronchini, R.

    1999-04-01

    Test masses coupled by weak mechanical suspensions are sensitive to differential forces such as the force due to a possible violation of the equivalence principle (EP). If in addition they are put in rapid rotation, the differential signal is modulated at high frequency, which is beneficial for noise reduction. Galileo Galilei (GG) is a proposed space experiment for testing the equivalence principle to 1 part in 0264-9381/16/4/032/img8 based on these concepts. A recent paper by Jafry and Weinberger (1998 Class. Quantum Grav. 15 481-500) claims that GG can only reach 0264-9381/16/4/032/img9. We show that the analysis of this paper is flawed (by several orders of magnitude) because of two misconceptions: one on the physical nature of mechanical damping and the other on active control methods for the stabilization of spinning bodies.

  6. Contra rotative propeller performance estimation

    OpenAIRE

    Coca Casanueva, Vladimir

    2008-01-01

    Due to the continuous increase in the fuel price, the propeller engine solution (the most efficient in fuel saving terms) becomes very attractive to airlines and thus, to aircraft manufacturers. However, airlines aren’t ready to fly an aircraft at lower cruise Mach number than the traditional Mach 0,84, which jeopardizes the fuel efficiency of propellers. At this stage is where the contra-rotative concept appears, which let us to increase the cruise speed while reducing fuel consumption...

  7. Core Angular Momentum and the IERS Sub-Centers Activity for Monitoring Global Geophysical Fluids. Part 1; Core Angular Momentum and Earth Rotation

    Science.gov (United States)

    Song, Xia-Dong; Chao, Benjamin (Technical Monitor)

    1999-01-01

    The part of the grant was to use recordings of seismic waves travelling through the earth's core (PKP waves) to study the inner core rotation and constraints on possible density anomalies in the fluid core. The shapes and relative arrival times of such waves associated with a common source were used to reduce the uncertainties in source location and excitation and the effect of unknown mantle structure. The major effort of the project is to assemble historical seismograms with long observing base lines. We have found original paper records of SSI earthquakes at COL between 1951 and 1966 in a warehouse of the U.S. Geological Survey office in Golden, Colorado, extending the previous measurements at COL by Song and Richards [1996] further back 15 years. Also in Alaska, the University of Alaska, Fairbanks Geophysical Institute (UAFGI) has been operating the Alaskan Seismic Network with over 100 stations since the late 1960s. Virtually complete archives of seismograms are still available at UAFGI. Unfortunately, most of the archives are in microchip form (develocorders), for which the use of waveforms is impossible. Paper seismograms (helicorders) are available for a limited number of stations, and digital recordings of analog signals started around 1989. Of the paper records obtained, stations at Gilmore Dome (GLM, very close to COL), Yukon (FYU), McKinley (MCK), and Sheep Creek Mountain (SCM) have the most complete continuous recordings.

  8. Simultaneity on the Rotating Disk

    Science.gov (United States)

    Koks, Don

    2017-04-01

    The disk that rotates in an inertial frame in special relativity has long been analysed by assuming a Lorentz contraction of its peripheral elements in that frame, which has produced widely varying views in the literature. We show that this assumption is unnecessary for a disk that corresponds to the simplest form of rotation in special relativity. After constructing such a disk and showing that observers at rest on it do not constitute a true rotating frame, we choose a "master" observer and calculate a set of disk coordinates and spacetime metric pertinent to that observer. We use this formalism to resolve the "circular twin paradox", then calculate the speed of light sent around the periphery as measured by the master observer, to show that this speed is a function of sent-direction and disk angle traversed. This result is consistent with the Sagnac Effect, but constitutes a finer analysis of that effect, which is normally expressed using an average speed for a full trip of the periphery. We also use the formalism to give a resolution of "Selleri's paradox".

  9. Adding a lens Improves spinning speed characterization.

    Science.gov (United States)

    Mihaliuk, Eugene; Gullion, Terry

    2015-11-01

    Highly stable sample rotation is important in many solid-state NMR experiments. Whether the necessary stability is achieved is not always clear. Typically only an average frequency over some time interval (often relatively long and unknown) is available from the spinning speed controller readout, which is not representative of the short-term variations of instantaneous rotation frequency. The necessity of the relatively slow measurement of spinning speed is a consequence of phase noise in the tachometer, which prevents speed measurement to be both rapid and precise at the same time. We show that adding a lens to the tachometer, without any other changes in the probe, reduces phase noise by nearly an order of magnitude and allows improved measurement of the spinning speed.

  10. Demonstration, Testing and Qualification of a High Temperature, High Speed Magnetic Thrust Bearing

    Science.gov (United States)

    DeWitt, Kenneth

    2005-01-01

    The gas turbine industry has a continued interest in improving engine performance and reducing net operating and maintenance costs. These goals are being realized because of advancements in aeroelasticity, materials, and computational tools such as CFD and engine simulations. These advancements aid in increasing engine thrust-to-weight ratios, specific fuel consumption, pressure ratios, and overall reliability through higher speed, higher temperature, and more efficient engine operation. Currently, rolling element bearing and squeeze film dampers are used to support rotors in gas turbine engines. Present ball bearing configurations are limited in speed (bearings require extensive preventative maintenance in order to assure their safe operation. Since these bearings are at their operational limits, new technologies must be found in order to take advantage of other advances. Magnetic bearings are well suited to operate at extreme temperatures and higher rotational speeds and are a promising solution to the problems that conventional rolling element bearings present. Magnetic bearing technology is being developed worldwide and is considered an enabling technology for new engine designs. Using magnetic bearings, turbine and compressor spools can be radically redesigned to be significantly larger and stiffer with better damping and higher rotational speeds. These advances, a direct result of magnetic bearing technology, will allow significant increases in engine power and efficiency. Also, magnetic bearings allow for real-time, in-situ health monitoring of the system, lower maintenance costs and down time.

  11. Models of soft rotators and the theory of a harmonic rotator

    CERN Document Server

    Zakir, Zahid

    2012-01-01

    The states of a planar oscillator are separated to a vibrational mode, containing a zero-point energy, and a rotational mode without the zero-point energy, but having a conserved angular momentum. On the basis of the analysis of properties of models of rigid and semirigid rotators, the theory of soft rotators is formulated where the harmonic attractive force is balanced only by the centrifugal force. As examples a Coulomb rotator (the Bohr model) and a magneto-harmonic rotator (the Fock-Landau levels) are considered. Disappearance of the radial speed in the model of a magneto-harmonic rotator is taken as a defining property of a pure rotational motion in the harmonic potential. After the exception of energies of the magnetic and spin decompositions, specific to magnetic fields, one turns to a simple and general model of a planar harmonic rotator (circular oscillator without radial speed) where kinetic energy is reduced to the purely rotational energy. Energy levels of the harmonic rotator have the same freque...

  12. Speed-Selector Guard For Machine Tool

    Science.gov (United States)

    Shakhshir, Roda J.; Valentine, Richard L.

    1992-01-01

    Simple guardplate prevents accidental reversal of direction of rotation or sudden change of speed of lathe, milling machine, or other machine tool. Custom-made for specific machine and control settings. Allows control lever to be placed at only one setting. Operator uses handle to slide guard to engage or disengage control lever. Protects personnel from injury and equipment from damage occurring if speed- or direction-control lever inadvertently placed in wrong position.

  13. Condition Monitoring and Fault Diagnosis for an Antifalling Safety Device

    Directory of Open Access Journals (Sweden)

    Guangxiang Yang

    2015-01-01

    Full Text Available There is a constant need for the safe operation and reliability of antifalling safety device (AFSD of an elevator. This paper reports an experimental study on rotation speed and catching torque monitoring and fault diagnosis of an antifalling safety device in a construction elevator. Denoising the signal using wavelet transform is presented in this paper. Based on the denoising effects for several types of wavelets, the sym8 wavelet basis, which introduces the high order approximation and an adaptive threshold, is employed for denoising the signal. The experimental result shows a maximum data error reduction of 7.5% is obtained and SNRs (signal-to-noise ratio of rotation speed and catching torque are improved for 3.9% and 6.4%, respectively.

  14. Rotating Wheel Wake

    Science.gov (United States)

    Lombard, Jean-Eloi; Xu, Hui; Moxey, Dave; Sherwin, Spencer

    2016-11-01

    For open wheel race-cars, such as Formula One, or IndyCar, the wheels are responsible for 40 % of the total drag. For road cars, drag associated to the wheels and under-carriage can represent 20 - 60 % of total drag at highway cruise speeds. Experimental observations have reported two, three or more pairs of counter rotating vortices, the relative strength of which still remains an open question. The near wake of an unsteady rotating wheel. The numerical investigation by means of direct numerical simulation at ReD =400-1000 is presented here to further the understanding of bifurcations the flow undergoes as the Reynolds number is increased. Direct numerical simulation is performed using Nektar++, the results of which are compared to those of Pirozzoli et al. (2012). Both proper orthogonal decomposition and dynamic mode decomposition, as well as spectral analysis are leveraged to gain unprecedented insight into the bifurcations and subsequent topological differences of the wake as the Reynolds number is increased.

  15. Droplets climbing a rotating helical fiber

    CERN Document Server

    Texier, Baptiste Darbois

    2015-01-01

    A liquid droplet is placed on a rotating helical fiber. We find that the droplet may slide down, attach or climb up the fiber. We inspect experimentally the domain of existence of these three behaviors as a function of the geometrical characteristics of the fiber, its angle relatively to the horizontal, the wetting properties of the fluid and the rotating speed of the helix. A theoretical model is proposed in order to capture the boundaries of the experimental phase diagram.

  16. Assessing the performance of the photo-acoustic infrared gas monitor for measuring CO(2), N(2)O, and CH(4) fluxes in two major cereal rotations.

    Science.gov (United States)

    Tirol-Padre, Agnes; Rai, Munmun; Gathala, Mahesh; Sharma, Sheetal; Kumar, Virender; Sharma, Parbodh C; Sharma, Dinesh K; Wassmann, Reiner; Ladha, Jagdish

    2014-01-01

    Rapid, precise, and globally comparable methods for monitoring greenhouse gas (GHG) fluxes are required for accurate GHG inventories from different cropping systems and management practices. Manual gas sampling followed by gas chromatography (GC) is widely used for measuring GHG fluxes in agricultural fields, but is laborious and time-consuming. The photo-acoustic infrared gas monitoring system (PAS) with on-line gas sampling is an attractive option, although it has not been evaluated for measuring GHG fluxes in cereals in general and rice in particular. We compared N2 O, CO2 , and CH4 fluxes measured by GC and PAS from agricultural fields under the rice-wheat and maize-wheat systems during the wheat (winter), and maize/rice (monsoon) seasons in Haryana, India. All the PAS readings were corrected for baseline drifts over time and PAS-CH4 (PCH4 ) readings in flooded rice were corrected for water vapor interferences. The PCH4 readings in ambient air increased by 2.3 ppm for every 1000 mg cm(-3) increase in water vapor. The daily CO2 , N2 O, and CH4 fluxes measured by GC and PAS from the same chamber were not different in 93-98% of all the measurements made but the PAS exhibited greater precision for estimates of CO2 and N2 O fluxes in wheat and maize, and lower precision for CH4 flux in rice, than GC. The seasonal GC- and PAS-N2 O (PN2 O) fluxes in wheat and maize were not different but the PAS-CO2 (PCO2 ) flux in wheat was 14-39% higher than that of GC. In flooded rice, the seasonal PCH4 and PN2 O fluxes across N levels were higher than those of GC-CH4 and GC-N2 O fluxes by about 2- and 4fold, respectively. The PAS (i) proved to be a suitable alternative to GC for N2 O and CO2 flux measurements in wheat, and (ii) showed potential for obtaining accurate measurements of CH4 fluxes in flooded rice after making correction for changes in humidity.

  17. EFFECT OF ORGANIC LOADING RATES FOR TREATING GREY WATER IN ROTATING BIOLOGICAL CONTACTORS

    Directory of Open Access Journals (Sweden)

    S. Syed Enayathali

    2012-05-01

    Full Text Available The laboratory model of two-stage Rotating Biological Contactor (RBC which was used in the present study is a modified one, with a rovision to vary the speed of rotating blades. Grey wastewater was used to study the performance of the modified rotating biological contactor. The reactor had four rotating blades in each stage, having the size of 300 mm x100 mm x 10 mm, attached perpendicular to the shaft. The experiment was conducted for different influent COD loads and different speeds of rotating blades. Among the different speedsof rotational blades in treating grey water, the rotational speed of 3 rpm was found to yield better percent removal of COD at 95.07% as maximum, where as against the rotational speeds of 4.5 and 6 rpm, the treatment efficiency is 95.04% and 94.96% respectively

  18. Visual perception of axes of head rotation

    Directory of Open Access Journals (Sweden)

    David Mattijs Arnoldussen

    2013-02-01

    Full Text Available Registration of ego-motion is important to accurately navigate through space. Movements of the head and eye relative to space are registered through the vestibular system and optical flow, respectively. Here, we address three questions concerning the visual registration of self-rotation. 1. Eye-in-head movements provide a link between the motion signals received by sensors in the moving eye and sensors in the moving head. How are these signals combined into an ego-rotation percept? We combined optic flow of simulated forward and rotational motion of the eye with different levels of eye-in-head rotation for a stationary head. We dissociated simulated gaze rotation and head rotation by different levels of eye-in-head pursuit.We found that perceived rotation matches simulated head- not gaze-rotation. This rejects a model for perceived self-rotation that relies on the rotation of the gaze line. Rather, eye-in-head signals serve to transform the optic flow’s rotation information, that specifies rotation of the scene relative to the eye, into a rotation relative to the head. This suggests that transformed visual self-rotation signals may combine with vestibular signals.2. Do transformed visual self-rotation signals reflect the arrangement of the semicircular canals (SCC? Previously, we found sub-regions within MST and V6+ that respond to the speed of the simulated head rotation. Here, we re-analyzed those BOLD signals for the presence of a spatial dissociation related to the axes of visually simulated head rotation, such as have been found in sub-cortical regions of various animals. Contrary, we found a rather uniform BOLD response to simulated rotation along the three SCC axes.3. We investigated if subject’s sensitivity to the direction of the head rotation axis shows SCC axes specifcity. We found that sensitivity to head rotation is rather uniformly distributed, suggesting that in human cortex, visuo-vestibular integration is not arranged into

  19. Experimental study on the effect of welding speed and tool pin ...

    African Journals Online (AJOL)

    user

    The FSW process parameters such as rotational speed, welding speed, axial force ... This technique is attractive for joining high strength aluminium alloys since there is ... These works enhance the difficulty in evaluating the dependence of the ...

  20. 多电机传动机械系统的转速智能检测与控制%Intelligent Test and Control on Rotate Speed of Multi-motor Transmission Mechanical System

    Institute of Scientific and Technical Information of China (English)

    常德宝; 徐磊

    2011-01-01

    Induction motor part of excavator systems is studied according to modern mechatronic idea, parameter measurement and description of speed control are carried out on the experimental induction motor, which makes the necessary preparations for laboratory furniture building and lays a solid foundation for the relationship between the load and the current of induction motor during operation , it is conducive for easy measured amount of current to achieve the detection of the external load motor. Combined with the research, the author summarizes the variation regularity of multi-machine system external load, which has practical value and significance.%本文以现代机电一体化思想对挖掘机系统中涉及感应电动机部分进行了研究,对实验台中所使用的感应电动机进行参数测量以及转速控制描述,为实验台的搭建做出了必要的准备,为研究感应电机在运行过程中负载与电流的关系打下了坚实的基础,有利于实现简便测得电流量来达到对电机外负载的检测目的.笔者通过本文的研究总结了多机系统的外负载变化规律,具有实用价值和研究意义.

  1. Measuring Torque and Temperature in a Rotating Shaft Using Commercial SAW Sensors

    Directory of Open Access Journals (Sweden)

    Diogo Silva

    2017-07-01

    Full Text Available Real-time monitoring of torque in a rotating shaft is not easy to implement with technologies such as optic fiber sensors or strain gages. Surface acoustic wave (SAW sensors are wireless and passive and can be used to monitor strain in moving parts. Commercial solutions (sensors, antennas and interrogation unit can easily be purchased from some companies; however, they are not customized and may not meet the specificity of the measurements. In order to evaluate the adequacy of commercial off-the-shelf (COTS solutions, temperature and strain sensors fabricated by SENSeOR (Besançon, France were mounted on a load cell. The sensors were calibrated using a thermal chamber and a universal testing machine. The load cell was then assembled together with a steel shaft that rotated at different speeds inside an oven. The commercial antennas were replaced with an RF (radio frequency coupler and the sensors were interrogated with the commercial interrogation unit. The influence of rotation in the accuracy on the measurements, as well as the adequacy of the sensors structure, was evaluated. It can be concluded that SAW sensors can be used to measure temperature or torque in a rotating environment; however, some customization of the components is required in order to overcome the limitations posed by COTS sensing solutions.

  2. Measuring Torque and Temperature in a Rotating Shaft Using Commercial SAW Sensors.

    Science.gov (United States)

    Silva, Diogo; Mendes, Joana C; Pereira, António B; Gégot, François; Alves, Luís N

    2017-07-02

    Real-time monitoring of torque in a rotating shaft is not easy to implement with technologies such as optic fiber sensors or strain gages. Surface acoustic wave (SAW) sensors are wireless and passive and can be used to monitor strain in moving parts. Commercial solutions (sensors, antennas and interrogation unit) can easily be purchased from some companies; however, they are not customized and may not meet the specificity of the measurements. In order to evaluate the adequacy of commercial off-the-shelf (COTS) solutions, temperature and strain sensors fabricated by SENSeOR (Besançon, France) were mounted on a load cell. The sensors were calibrated using a thermal chamber and a universal testing machine. The load cell was then assembled together with a steel shaft that rotated at different speeds inside an oven. The commercial antennas were replaced with an RF (radio frequency) coupler and the sensors were interrogated with the commercial interrogation unit. The influence of rotation in the accuracy on the measurements, as well as the adequacy of the sensors structure, was evaluated. It can be concluded that SAW sensors can be used to measure temperature or torque in a rotating environment; however, some customization of the components is required in order to overcome the limitations posed by COTS sensing solutions.

  3. Speed of light as measured by two terrestrial stable clocks

    Science.gov (United States)

    Hsu, J. P.; Sherry, T. N.; Chiu, C. B.

    1977-01-01

    Despite the recent criticism within the special theory of relativity, there exists an arrangement of stable clocks rotating with the earth which predicts diurnal variations of the one-way speed of light, as suggested previously.

  4. implementation and comparative study of a high speed multimode ...

    African Journals Online (AJOL)

    SUMAN HALDAR, SOUMITA HALDAR CHAKRABORTY, PRADIPTAMAITI, PRATIK KUMAR SINHA, PIJUSH BISWAS, Dr. AMITAVA SINHA

    2016-07-07

    Jul 7, 2016 ... The key feature of the work is reduced power and simple circuitry, without ... Keywords: Digital Communication, Multimode Modulator, High Speed ..... Implementation of Universal Modulator using Co-ordinate Rotation Digital ...

  5. Potential of a newly developed high-speed near-infrared (NIR) camera (Compovision) in polymer industrial analyses: monitoring crystallinity and crystal evolution of polylactic acid (PLA) and concentration of PLA in PLA/Poly-(R)-3-hydroxybutyrate (PHB) blends.

    Science.gov (United States)

    Ishikawa, Daitaro; Nishii, Takashi; Mizuno, Fumiaki; Sato, Harumi; Kazarian, Sergei G; Ozaki, Yukihiro

    2013-12-01

    This study was carried out to evaluate a new high-speed hyperspectral near-infrared (NIR) camera named Compovision. Quantitative analyses of the crystallinity and crystal evolution of biodegradable polymer, polylactic acid (PLA), and its concentration in PLA/poly-(R)-3-hydroxybutyrate (PHB) blends were investigated using near-infrared (NIR) imaging. This NIR camera can measure two-dimensional NIR spectral data in the 1000-2350 nm region obtaining images with wide field of view of 150 × 250 mm(2) (approximately 100  000 pixels) at high speeds (in less than 5 s). PLA with differing crystallinities between 0 and 50% blended samples with PHB in ratios of 80/20, 60/40, 40/60, 20/80, and pure films of 100% PLA and PHB were prepared. Compovision was used to collect respective NIR spectra in the 1000-2350 nm region and investigate the crystallinity of PLA and its concentration in the blends. The partial least squares (PLS) regression models for the crystallinity of PLA were developed using absorbance, second derivative, and standard normal variate (SNV) spectra from the most informative region of the spectra, between 1600 and 2000 nm. The predicted results of PLS models achieved using the absorbance and second derivative spectra were fairly good with a root mean square error (RMSE) of less than 6.1% and a determination of coefficient (R(2)) of more than 0.88 for PLS factor 1. The results obtained using the SNV spectra yielded the best prediction with the smallest RMSE of 2.93% and the highest R(2) of 0.976. Moreover, PLS models developed for estimating the concentration of PLA in the blend polymers using SNV spectra gave good predicted results where the RMSE was 4.94% and R(2) was 0.98. The SNV-based models provided the best-predicted results, since it can reduce the effects of the spectral changes induced by the inhomogeneity and the thickness of the samples. Wide area crystal evolution of PLA on a plate where a temperature slope of 70-105 °C had occurred was also

  6. Analysis of counter-rotating wind turbines

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Zakkam, Vinod Arun Kumar; Sørensen, Jens Nørkær

    2007-01-01

    This paper presents a study on the performance of a wind turbine with two counter-rotating (CRWT) rotors. The characteristics of the two counter-rotating rotors are on a 3-bladed Nordtank 500 kW rotor. The analysis has been carried out by using an Actuator Line technique implemented in the Navier......-Stokes code EllipSys3D. The analysis shows that the Annual Energy Production can be increased to about 43.5 %, as compared to a wind turbine with a single rotor. In order to determine the optimal settings of the CRWT turbine, parameters such as distance between two rotors and rotational speed have been...

  7. Synergic effects of 10°/s constant rotation and rotating background on visual cognitive processing

    Science.gov (United States)

    He, Siyang; Cao, Yi; Zhao, Qi; Tan, Cheng; Niu, Dongbin

    In previous studies we have found that constant low-speed rotation facilitated the auditory cognitive process and constant velocity rotation background sped up the perception, recognition and assessment process of visual stimuli. In the condition of constant low-speed rotation body is exposed into a new physical state. In this study the variations of human brain's cognitive process under the complex condition of constant low-speed rotation and visual rotation backgrounds with different speed were explored. 14 university students participated in the ex-periment. EEG signals were recorded when they were performing three different cognitive tasks with increasing mental load, that is no response task, selective switch responses task and selec-tive mental arithmetic task. Rotary chair was used to create constant low-speed10/srotation. Four kinds of background were used in this experiment, they were normal black background and constant 30o /s, 45o /s or 60o /s rotating simulated star background. The P1 and N1 compo-nents of brain event-related potentials (ERP) were analyzed to detect the early visual cognitive processing changes. It was found that compared with task performed under other backgrounds, the posterior P1 and N1 latencies were shortened under 45o /s rotating background in all kinds of cognitive tasks. In the no response task, compared with task performed under black back-ground, the posterior N1 latencies were delayed under 30o /s rotating background. In the selec-tive switch responses task and selective mental arithmetic task, compared with task performed under other background, the P1 latencies were lengthened under 60o /s rotating background, but the average amplitudes of the posterior P1 and N1 were increased. It was suggested that under constant 10/s rotation, the facilitated effect of rotating visual background were changed to an inhibited one in 30o /s rotating background. Under vestibular new environment, not all of the rotating backgrounds

  8. The intimate relation between the low T/W instability and the co-rotation point

    CERN Document Server

    Passamonti, Andrea

    2014-01-01

    We study the low T/W instability associated with the f-mode of differentially rotating stars. Our stellar models are described by a polytropic equation of state and the rotation profile is given by the standard j-constant law. The properties of the relevant oscillation modes, including the instability growth time, are determined from time evolutions of the linearised dynamical equations in Newtonian gravity. In order to analyse the instability we monitor also the canonical energy and angular momentum. Our results demonstrate that the l=m=2 f-mode becomes unstable as soon as a co-rotation point develops inside the star (i.e. whenever there is a point where the mode's pattern speed matches the bulk angular velocity). Considering various degrees of differential rotation, we show that the instability grows faster deep inside the co-rotation region and deduce an empirical relation that correlates the mode frequency and the star's parameters, which captures the main features of the l=m=2 f-mode growth time. This fu...

  9. Event alignment, warping between running speeds

    DEFF Research Database (Denmark)

    Pontoppidan, Niels Henrik; Douglas, Ryan

    2004-01-01

    marine conditions (different load settings on the propeller curve) was in the range from 60 to 120 rotations per minute; furthermore the running speed was stable within periods of fixed load. Electronically controlled engines can change the angular timing of certain events, such as fuel injection...

  10. A Diagnostic System for Speed-Varying Motor Rotary Faults

    Directory of Open Access Journals (Sweden)

    Chwan-Lu Tseng

    2014-01-01

    Full Text Available This study proposed an intelligent rotary fault diagnostic system for motors. A sensorless rotational speed detection method and an improved dynamic structural neural network are used. Moreover, to increase the convergence speed of training, a terminal attractor method and a hybrid discriminant analysis are also adopted. The proposed method can be employed to detect the rotary frequencies of motors with varying speeds and can enhance the discrimination of motor faults. To conduct the experiments, this study used wireless sensor nodes to transmit vibration data and employed MATLAB to write codes for functional modules, including the signal processing, sensorless rotational speed estimation, neural network, and stochastic process control chart. Additionally, Visual Basic software was used to create an integrated human-machine interface. The experimental results regarding the test of equipment faults indicated that the proposed novel diagnostic system can effectively estimate rotational speeds and provide superior ability of motor fault discrimination with fast training convergence.

  11. Method and apparatus for monitoring motor operated valve motor output torque and power at valve seating

    Science.gov (United States)

    Casada, Donald A.

    1996-01-01

    A method and apparatus are provided for monitoring a motor operated valve during the brief period when the valve seats and the torque switch trips to deenergize the valve motor. The method uses voltage measurements on the load side of a deenergizing switch that opens to deenergize the motor to determine, among other things, final motor rotational speed and the decelerating torque at motor deenergization.

  12. Rotator cuff exercises

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000357.htm Rotator cuff exercises To use the sharing features on this ... gov/pubmed/25560729 . Read More Frozen shoulder Rotator cuff problems Rotator cuff repair Shoulder arthroscopy Shoulder CT scan Shoulder ...

  13. Rotating Cavitation Supression Project

    Data.gov (United States)

    National Aeronautics and Space Administration — FTT proposes development of a rotating cavitation (RC) suppressor for liquid rocket engine turbopump inducers. Cavitation instabilities, such as rotating...

  14. Smaller Footprint Drilling System for Deep and Hard Rock Environments; Feasibility of Ultra-High-Speed Diamond Drilling

    Energy Technology Data Exchange (ETDEWEB)

    TerraTek, A Schlumberger Company

    2008-12-31

    The two phase program addresses long-term developments in deep well and hard rock drilling. TerraTek believes that significant improvements in drilling deep hard rock will be obtained by applying ultra-high rotational speeds (greater than 10,000 rpm). The work includes a feasibility of concept research effort aimed at development that will ultimately result in the ability to reliably drill 'faster and deeper' possibly with smaller, more mobile rigs. The principle focus is on demonstration testing of diamond bits rotating at speeds in excess of 10,000 rpm to achieve high rate of penetration (ROP) rock cutting with substantially lower inputs of energy and loads. The significance of the 'ultra-high rotary speed drilling system' is the ability to drill into rock at very low weights on bit and possibly lower energy levels. The drilling and coring industry today does not practice this technology. The highest rotary speed systems in oil field and mining drilling and coring today run less than 10,000 rpm - usually well below 5,000 rpm. This document provides the progress through two phases of the program entitled 'Smaller Footprint Drilling System for Deep and Hard Rock Environments: Feasibility of Ultra-High-Speed Diamond Drilling' for the period starting 30 June 2003 and concluding 31 March 2009. The accomplishments of Phases 1 and 2 are summarized as follows: (1) TerraTek reviewed applicable literature and documentation and convened a project kick-off meeting with Industry Advisors in attendance (see Black and Judzis); (2) TerraTek designed and planned Phase I bench scale experiments (See Black and Judzis). Improvements were made to the loading mechanism and the rotational speed monitoring instrumentation. New drill bit designs were developed to provided a more consistent product with consistent performance. A test matrix for the final core bit testing program was completed; (3) TerraTek concluded small-scale cutting performance tests; (4

  15. Extracting full-field dynamic strain response of a rotating wind turbine using photogrammetry

    Science.gov (United States)

    Baqersad, Javad; Poozesh, Peyman; Niezrecki, Christopher; Avitabile, Peter

    2015-04-01

    Health monitoring of wind turbines is typically performed using conventional sensors (e.g. strain-gages and accelerometers) that are usually mounted to the nacelle or gearbox. Although many wind turbines stop operating due to blade failures, there are typically few to no sensor mounted on the blades. Placing sensors on the rotating parts of the structure is a challenge due to the wiring and data transmission constraints. Within the current work, an approach to monitor full-field dynamic response of rotating structures (e.g. wind turbine blades or helicopter rotors) is developed and experimentally verified. A wind turbine rotor was used as the test structure and was mounted to a block and horizontally placed on the ground. A pair of bearings connected to the rotor shaft allowed the turbine to freely spin along the shaft. Several optical targets were mounted to the blades and a pair of high-speed cameras was used to monitor the dynamics of the spinning turbine. Displacements of the targets during rotation were measured using three-dimensional point tracking. The point tracking technique measured both rigid body displacement and flexible deformation of the blades at target locations. While the structure is rotating, only flap displacements of optical targets (displacements out of the rotation plane) were used in strain prediction process. The measured displacements were expanded and applied to the finite element model of the turbine to extract full-field dynamic strain on the structure. The proposed approach enabled the prediction of dynamic response on the outer surface as well as within the inner points of the structure where no other sensor could be easily mounted. In order to validate the proposed approach, the predicted strain was compared to strain measured at four locations on the spinning blades using a wireless strain-gage system.

  16. 一种用于检测转角、转速和转矩的新型多功能非接触式传感器%A New Multifunction Non-Contact Sensor to Measure Angle, Rotational Speed and Torque

    Institute of Scientific and Technical Information of China (English)

    石延平; 范书华; 臧勇

    2012-01-01

    A new multifunction non-contact sensor based on nanocrystalline soft magnetic alloy was discussed, it can be used for measuring angle, rotational speed and torque. The principle and structure of the sensor were presented, and its output characteristic equation and sensitivity formula were derived. By making a measuring experiment, the effect of the exciting field intensity on measurement accuracy was analyzed, and its optimum value was got. At 25 ℃ ~ 100 ℃,the effect of shift in temperature on sensor output also was studied,and its temperature drift no-loading was 0.002% F. S/℃ ;When making a loading torsion test in 0 ~450 N·m,more sensitivity and more low error in linearity, repeatability and hysteresis were achieved. At 500 r/min ~3 523 r/min, maximum rotational speed relative error was 0. 60%. The experimental result shows the sensor's measurement precision is 1.0% ,and it can be used for general engineering applications.%对一种基于纳米晶软磁合金的非接触式,用于测量转角、转速和转矩的多功能传感器进行了研究.介绍了传感器的结构和原理,推导出传感器的输出方程和灵敏度表达式.通过试验,分析了传感器激磁磁场强度对转矩测量精度的影响,并得出了最佳激磁磁场强度;在25℃~100℃范围研究了温度变化对传感器输出的影响,其零点温度漂移(25℃)为0.002%F.S/℃;在0~450 N·m范围进行转矩加载,得到了较高的测量灵敏度以及较低的线性度误差、重复度误差及迟滞静态误差;在500 r/min~3 523 r/min范围内,转速最大相对误差为0.60%.试验数据显示,该传感器的精度能够达到1.0%,对于一般工程应用是可行的.

  17. Intelligent Tool Wear Condition Monitoring System with High Adaptability in High Speed Milling Process%具备高适应性的高速铣削刀具磨损状态监测系统

    Institute of Scientific and Technical Information of China (English)

    申志刚; 何宁

    2013-01-01

    To enhance the adaptability of tool condition monitoring(TCM) system, an novel and intelligent method is proposed for automatic identifying the different tool wear states and estimating the wear value with no need of the pre-designed "teaching" or "training" phase. Automatic sensory feature selection method is used to aid the systematic design of TCM, and to suppress interference introduced by changes of cutting parameter. Force and acoustic emission sensors are used in high speed milling operations. The time domain, frequency domain and wavelet analysis techniques are applied to processing the signals. The real-time intelligent monitoring system is built on the cycle process of linear fitting and Ma-halanobis distance (MD) calculating. A series of experiment application on a CNC vertical milling machine tool show that the proposed method is accurate for feature extraction and efficient for condition monitoring of cutting tools.%为提高加工监测系统的适应性和智能化程度,提出基于刀具磨损曲线的实时刀具状态监测系统.自学习能力的引入使该系统可自动进行不同刀具状态的识别和磨损程度的估计,较大程度上摆脱对系统事先“教学”的依赖.同时为有效抑制切削参数变化带来的干扰,提出一种特征提取方法来自动提取敏感特征,减少监测系统开发时间和成本.针对高速铣削过程的刀具磨损监测,采用切削力和声发射传感器来采集信号,并运用时域、频域和小波分析技术来对信号进行处理,试验结果证明了所提出的自动特征提取方法的有效性和智能刀具状态监测系统的高适应性.

  18. Three-dimensional flow past rotating wing at low Reynolds number: a computational study

    Energy Technology Data Exchange (ETDEWEB)

    Ruifeng, Hu, E-mail: rfhu@xidian.edu.cn [School of Mechano-Electronic Engineering, Xidian University, Xi’an 710071 (China)

    2015-08-15

    In this work, we performed a computational study on the three-dimensional (3D) flow past a rotating wing at a low Reynolds number (Re = 200). The 3D vortical structures and aerodynamic performances of the rotating wing with different aspect ratios and rotating speeds are computed and analyzed. A quasi-steady model is adopted for prediction of aerodynamic performances of the wing, and its applicability is evaluated by the computation. It is found that there exists a periodic vortex shedding pattern at a low rotating speed, while vortices may cluster near the wing when rotating speed is high enough. The wake vortex topology is also affected by the aspect ratio. The current quasi-steady aerodynamic model could only be used for rotating wing aerodynamics at a low rotating speed when regularly periodic vortex shedding exists. (paper)

  19. Upper atmospheric rotation rate from orbit analysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The rotation speed Λ of the upper atmosphere,mainly at heights of 180-360 km,was evaluated from the changes in orbital inclinations of GFZ. The results indicate that the value of Λ(in rev/d) decreases from 1.2 at 360 km to 0.9 at 180 km.

  20. Application of advanced materials to rotating machines

    Science.gov (United States)

    Triner, J. E.

    1983-01-01

    In discussing the application of advanced materials to rotating machinery, the following topics are covered: the torque speed characteristics of ac and dc machines, motor and transformer losses, the factors affecting core loss in motors, advanced magnetic materials and conductors, and design tradeoffs for samarium cobalt motors.

  1. Development of monitoring unit for shaft generator set syetem with performances of variable speed and constant frequency%变速恒频轴带发电机组监控系统的研制

    Institute of Scientific and Technical Information of China (English)

    洪鹏鹏; 南余荣; 石健将

    2013-01-01

    Aiming at solving the problems of low efficiency, high pollution and complex monitoring in the traditional hybrid propulsion system on ship, the shaft generator set system with performances of variable speed and constant frequency was applied in the new hybrid propulsion system. A four-quadrant inverter was added between the shaft generator and the micro grid on ship, whose performances were researched in different working modes. A monitoring unit was developed to communicate with the controllers through CAN bus and the ship information management platform through Profibus. A TMS320F28335 was applied as the controller of the monitoring unit, while the LCD module was used as the displaying interface. The display of system state, working parameters, commands and data transferred were all completed by the monitoring unit. The experimental results indicate that the new hybrid propulsion system can work steadily in different working modes, while reducing the pollution and improving the efficiency of the system. At the same time, the monitoring unit is human friendly with flexiable operating performance and the communication is stable and reliable, which is fit for industrial application.%针对传统的船舶混合推进系统中存在效率低、污染高、工作模式单一、监控麻烦等问题,将变速恒频轴带发电机组系统应用于新型混合推进系统,在传统的轴带发电机和船舶微电网间添加了一个四象限变频器,对新型混合推进系统在不同工作模式下的系统性能进行了研究;同时设计了一个监控系统,采用TMS320F28335作为控制芯片,与底层控制器之间采用CAN总线通信,与上层的船舶综合信息管理平台之间采用Profibus总线通信,显示部分采用液晶模块,完成了系统实时控制、状态参数在线监测及命令数据传输等功能.实验结果表明,新型混合推进系统能够在不同模式工作下稳定工作,降低了燃油成本和污染,提高了系统

  2. Observation of nondispersing classical-like molecular rotation

    CERN Document Server

    Korobenko, Aleksey; Milner, Valery

    2014-01-01

    Using the technique of an optical centrifuge, we produce rotational wave packets which evolve in time along either classical-like or non-classical trajectories. After releasing O2 and D2 molecules from the centrifuge, we track their field-free rotation by monitoring the molecular angular distribution with velocity map imaging. Due to the dispersion of the created rotational wave packets in oxygen, we observe a gradual transition between "dumbbell"-shaped and "cross"-shaped distributions, both rotating with a classical rotation frequency. In deuterium, a much narrower rotational wave packet is produced and shown to evolve in a truly classical non-dispersing fashion.

  3. Visual information processing in the lion-tailed macaque (Macaca silenus): mental rotation or rotational invariance?

    Science.gov (United States)

    Burmann, Britta; Dehnhardt, Guido; Mauck, Björn

    2005-01-01

    Mental rotation is a widely accepted concept indicating an image-like mental representation of visual information and an analogue mode of information processing in certain visuospatial tasks. In the task of discriminating between image and mirror-image of rotated figures, human reaction times increase with the angular disparity between the figures. In animals, tests of this kind yield inconsistent results. Pigeons were found to use a time-independent rotational invariance, possibly indicating a non-analogue information processing system that evolved in response to the horizontal plane of reference birds perceive during flight. Despite similar ecological demands concerning the visual reference plane, a sea lion was found to use mental rotation in similar tasks, but its processing speed while rotating three-dimensional stimuli seemed to depend on the axis of rotation in a different way than found for humans in similar tasks. If ecological demands influence the way information processing systems evolve, hominids might have secondarily lost the ability of rotational invariance while retreating from arboreal living and evolving an upright gait in which the vertical reference plane is more important. We therefore conducted mental rotation experiments with an arboreal living primate species, the lion-tailed macaque. Performing a two-alternative matching-to-sample procedure, the animal had to decide between rotated figures representing image and mirror-image of a previously shown upright sample. Although non-rotated stimuli were recognized faster than rotated ones, the animal's mean reaction times did not clearly increase with the angle of rotation. These results are inconsistent with the mental rotation concept but also cannot be explained assuming a mere rotational invariance. Our study thus seems to support the idea of information processing systems evolving gradually in response to specific ecological demands.

  4. CdS films deposited by chemical bath under rotation

    Energy Technology Data Exchange (ETDEWEB)

    Oliva-Aviles, A.I., E-mail: aoliva@mda.cinvestav.mx [Centro de Investigacion y de Estudios Avanzados Unidad Merida, Departamento de Fisica Aplicada. A.P. 73-Cordemex, 97310 Merida, Yucatan (Mexico); Patino, R.; Oliva, A.I. [Centro de Investigacion y de Estudios Avanzados Unidad Merida, Departamento de Fisica Aplicada. A.P. 73-Cordemex, 97310 Merida, Yucatan (Mexico)

    2010-08-01

    Cadmium sulfide (CdS) films were deposited on rotating substrates by the chemical bath technique. The effects of the rotation speed on the morphological, optical, and structural properties of the films were discussed. A rotating substrate-holder was fabricated such that substrates can be taken out from the bath during the deposition. CdS films were deposited at different deposition times (10, 20, 30, 40 and 50 min) onto Corning glass substrates at different rotation velocities (150, 300, 450, and 600 rpm) during chemical deposition. The chemical bath was composed by CdCl{sub 2}, KOH, NH{sub 4}NO{sub 3} and CS(NH{sub 2}){sub 2} as chemical reagents and heated at 75 deg. C. The results show no critical effects on the band gap energy and the surface roughness of the CdS films when the rotation speed changes. However, a linear increase on the deposition rate with the rotation energy was observed, meanwhile the stoichiometry was strongly affected by the rotation speed, resulting a better 1:1 Cd/S ratio as speed increases. Rotation effects may be of interest in industrial production of CdTe/CdS solar cells.

  5. Newton Algorithms for Analytic Rotation: An Implicit Function Approach

    Science.gov (United States)

    Boik, Robert J.

    2008-01-01

    In this paper implicit function-based parameterizations for orthogonal and oblique rotation matrices are proposed. The parameterizations are used to construct Newton algorithms for minimizing differentiable rotation criteria applied to "m" factors and "p" variables. The speed of the new algorithms is compared to that of existing algorithms and to…

  6. Newton Algorithms for Analytic Rotation: An Implicit Function Approach

    Science.gov (United States)

    Boik, Robert J.

    2008-01-01

    In this paper implicit function-based parameterizations for orthogonal and oblique rotation matrices are proposed. The parameterizations are used to construct Newton algorithms for minimizing differentiable rotation criteria applied to "m" factors and "p" variables. The speed of the new algorithms is compared to that of existing algorithms and to…

  7. The Concept of Speed Applied to Rigid Bodies in Rotation: Same alternative conceptions, varied interpretations O Conceito de Velocidade Aplicado em Corpos Rígidos em Rotação: mesmas concepções alternativas, variadas interpretações

    Directory of Open Access Journals (Sweden)

    Marcelo Alves Barros

    2004-11-01

    Full Text Available This work presents an investigation where some alternative conceptions are the origin and the processing of varied interpretations. As for that, it was proposed to high school students the resolution of certain problems that involved rigid bodies in constant rotation. These problems should be analysed within the perspective of the speed concept, which was previously known by the students, but abandoned by the explanations generated by the alternative conceptions.Este trabalho apresenta uma investigação em que algumas concepções alternativas são a origem e o desencadeamento de variadas interpretações. Para isso, foram propostos a alunos do ensino médio a resolução de determinados problemas que envolviam corpos rígidos em rotação constante. Estes problemas deveriam ser analisados dentro da perspectiva do conceito de velocidade, previamente conhecido dos alunos, mas abandonado pelas explicações geradas pelas concepções alternativas.

  8. Measurement of Phase Difference for Micromachined Gyros Driven by Rotating Aircraft

    OpenAIRE

    Wei Zhang; Zengping Zhang; Fuxue Zhang

    2013-01-01

    This paper presents an approach for realizing a phase difference measurement of a new gyro. A silicon micromachined gyro was mounted on rotating aircraft for aircraft attitude control. Aircraft spin drives the silicon pendulum of a gyro rotating at a high speed so that it can sense the transverse angular velocity of the rotating aircraft based on the gyroscopic precession principle when the aircraft has transverse rotation. In applications of the rotating aircraft single channel control syste...

  9. Measures for speed management.

    NARCIS (Netherlands)

    2009-01-01

    Measures for speed management are essential for limiting the negative effects of driving too fast and at inappropriate speeds. To begin with, safe and credible speed limits need to be determined. Dynamic and variable speed limits that take into account the current circumstances, such as weather cond

  10. High speed data converters

    CERN Document Server

    Ali, Ahmed MA

    2016-01-01

    This book covers high speed data converters from the perspective of a leading high speed ADC designer and architect, with a strong emphasis on high speed Nyquist A/D converters. For our purposes, the term 'high speed' is defined as sampling rates that are greater than 10 MS/s.

  11. Rotationally Vibrating Electric-Field Mill

    Science.gov (United States)

    Kirkham, Harold

    2008-01-01

    A proposed instrument for measuring a static electric field would be based partly on a conventional rotating-split-cylinder or rotating-split-sphere electric-field mill. However, the design of the proposed instrument would overcome the difficulty, encountered in conventional rotational field mills, of transferring measurement signals and power via either electrical or fiber-optic rotary couplings that must be aligned and installed in conjunction with rotary bearings. Instead of being made to rotate in one direction at a steady speed as in a conventional rotational field mill, a split-cylinder or split-sphere electrode assembly in the proposed instrument would be set into rotational vibration like that of a metronome. The rotational vibration, synchronized with appropriate rapid electronic switching of electrical connections between electric-current-measuring circuitry and the split-cylinder or split-sphere electrodes, would result in an electrical measurement effect equivalent to that of a conventional rotational field mill. A version of the proposed instrument is described.

  12. Mental rotation performance in male soccer players.

    Directory of Open Access Journals (Sweden)

    Petra Jansen

    Full Text Available It is the main goal of this study to investigate the visual-spatial cognition in male soccer players. Forty males (20 soccer players and 20 non-athletes solved a chronometric mental rotation task with both cubed and embodied figures (human figures, body postures. The results confirm previous results that all participants had a lower mental rotation speed for cube figures compared to embodied figures and a higher error rate for cube figures, but only at angular disparities greater than 90°. It is a new finding that soccer-players showed a faster reaction time for embodied stimuli. Because rotation speed did not differ between soccer-players and non-athletes this finding cannot be attributed to the mental rotation process itself but instead to differences in one of the following processes which are involved in a mental rotation task: the encoding process, the maintanence of readiness, or the motor process. The results are discussed against the background of the influence on longterm physical activity on mental rotation and the context of embodied cognition.

  13. Enhanced azimuthal rotation of the large-scale flow through stochastic cessations in turbulent rotating convection with large Rossby numbers

    CERN Document Server

    Zhong, Jin-Qiang; Wang, Xue-ying

    2016-01-01

    We present measurements of the azimuthal orientation {\\theta}(t) and thermal amplitude {\\delta}(t) of the large-scale circulation (LSC) of turbulent rotating convection within an unprecedented large Rossby number range 170. We identify the mechanism through which the mean retrograde rotation speed can be enhanced by stochastic cessations in the presence of weak Coriolis force, and show that a low-dimensional, stochastic model provides predictions of the observed large-scale flow dynamics and interprets its retrograde rotation.

  14. 输电线路超声波自校正风速风向监测系统的设计%Ultrasonic Wind Speed and Dircetion Monitor System of Transmission Line

    Institute of Scientific and Technical Information of China (English)

    李佳奇; 刘松; 赵义松

    2015-01-01

    针对传统输电线路机械式风速风向采集系统的不足,设计了一种以ARM为核心的风速风向采集仪。该系统采用STM32处理器,以超声波时差法为测试手段,同时采用温度补偿技术,地磁角校正技术以及GPS定位技术,实现了输电线路风速风向的准确监测,并通过GPRS实时发送数据至主控室。该系统具有免维护、功耗低、精度高、安装方便等优点,可广泛用在输电线路监测环境中。%To overcome shortcomings of traditional mechanical anemometer wind acquisition system of power transmission line , the ARM wind collect instrument was designed.The system used STM32as processor,ultrasonic-time-difference testing method and temperature compensation technology,geomagnetic angle correcting and GPS positioning technology realizing accurate test of wind speed and wind direction of transmission line,and the collected data can be realt-ime transmitted to the main control room.The sys-tem is free-maintenance, and has low power consumption,high precision,and convenient installation,which can be widely used in power transmission line monitoring environment.

  15. Speed of sound and acoustic attenuation of compounds affected during optoacoustic monitoring of thermal therapies measured in the temperature range from 5°C to 60°C

    Science.gov (United States)

    Oruganti, Tanmayi; Petrova, Elena; Oraevsky, Alexander A.; Ermilov, Sergey A.

    2015-03-01

    Optoacoustic (photoacoustic) imaging is being adopted for monitoring tissue temperature during hypothermic and hyperthermic cancer treatments. The technique's accuracy benefits from the knowledge of speed of sound (SoS) and acoustic coefficient of attenuation (AcA) as they change with temperature in biological tissues, blood, and acoustic lens of an ultrasound probe. In these studies we measured SoS and AcA of different ex vivo tissues and blood components (plasma and erythrocyte concentrates) in the temperature range from 5°C to 60°C. We used the technique based on measurements of time-delay and spectral amplitude of pressure pulses generated by wideband planar acoustic waves propagating through the interrogated medium. Water was used as a reference medium with known acoustic properties. In order to validate our experimental technique, we measured the temperature dependence of SoS and AcA for aqueous NaCl solution of known concentration and obtained the results in agreement with published data. Similar to NaCl solution and pure water, SoS in blood and plasma was monotonously increasing with temperature. However, SoS of erythrocyte concentrates displayed abnormalities at temperatures above 45°C, suggesting potential effects from hemoglobin denaturation and/or hemolysis of erythrocytes. On the contrary to aqueous solutions, the SoS in polyvinyl-chloride (plastisol) - a material frequently used for mimicking optical and acoustic properties of tissues - decreased with temperature. We also measured SoS and AcA in silicon material of an acoustic lens and did not observe temperature-related changes of SoS.

  16. ANALYSIS ON MOTION STABILITY OF A HIGH-SPEED ROTOR-BEARING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Zhang Junhong; Sun Shaojun

    2005-01-01

    A non-linear dynamic model of one type of high-speed rotor system with gas supporting system is set up. The laws between the capacity force and the parameters of bearing, the static equilibrium position and rotating speed are studied on the basis of above model. Then, the failure rotating speed is given in the working state, and the relation between the minimum failure rotating speed and clearance of bearing is also studied. At last, the stability and failure condition are discussed in different working conditions.

  17. A Novel Motor-Speed-Regulation Method

    Directory of Open Access Journals (Sweden)

    Huang Zhou

    2016-01-01

    Full Text Available The traditional doubly-fed motor has less reliability because it needs carbon brushes and sliding rings which are not highly reliable. The brushless doubly-fed machine costs a lot for its framework requires special designing and processing. To overcome the disadvantages of the two kinds of motors, this paper focuses on a novel method of motor speed regulation which is based on rotating feeding. The motor speed changing around its rated speed can be realized based on the method without any carbon brush or sliding ring on the prosaic electrical motors. On the basis of the full controlled thyristor rectifying bridge structure, the basic idea is introduced; the advantages and disadvantages of this method are analyzed. This kind of systems can replace the brushed or brushless double-fed systems. They are very suitable for driving fans or pumps, or power-generating systems with variable speed constant frequency such as wind power or water power generating systems.

  18. Protodiscs around Hot Magnetic Rotator Stars

    CERN Document Server

    Maheswaran, M

    2008-01-01

    We develop equations and obtain solutions for the structure and evolution of a protodisc region that is initially formed with no radial motion and super-Keplerian rotation speed when wind material from a hot rotating star is channelled towards its equatorial plane by a dipole-type magnetic field. Its temperature is around $10^7$K because of shock heating and the inflow of wind material causes its equatorial density to increase with time. The centrifugal force and thermal pressure increase relative to the magnetic force and material escapes at its outer edge. The protodisc region of a uniformly rotating star has almost uniform rotation and will shrink radially unless some instability intervenes. In a star with angular velocity increasing along its surface towards the equator, the angular velocity of the protodisc region decreases radially outwards and magnetorotational instability (MRI) can occur within a few hours or days. Viscosity resulting from MRI will readjust the angular velocity distribution of the pro...

  19. Fourier analysis for rotating-element ellipsometers.

    Science.gov (United States)

    Cho, Yong Jai; Chegal, Won; Cho, Hyun Mo

    2011-01-15

    We introduce a Fourier analysis of the waveform of periodic light-irradiance variation to capture Fourier coefficients for multichannel rotating-element ellipsometers. In this analysis, the Fourier coefficients for a sample are obtained using a discrete Fourier transform on the exposures. The analysis gives a generic function that encompasses the discrete Fourier transform or the Hadamard transform, depending on the specific conditions. Unlike the Hadamard transform, a well-known data acquisition method that is used only for conventional multichannel rotating-element ellipsometers with line arrays with specific readout-mode timing, this Fourier analysis is applicable to various line arrays with either nonoverlap or overlap readout-mode timing. To assess the effects of the novel Fourier analysis, the Fourier coefficients for a sample were measured with a custom-built rotating-polarizer ellipsometer, using this Fourier analysis with various numbers of scans, integration times, and rotational speeds of the polarizer.

  20. Estimation of Near Surface Wind Speeds in Strongly Rotating Flows

    CERN Document Server

    Crowell, Sean; Wicker, Louis

    2013-01-01

    Modeling studies consistently demonstrate that the most violent winds in tornadic vortices occur in the lowest tens of meters above the surface. These velocities are unobservable by radar platforms due to line of sight consider- ations. In this work, a methodology is developed which utilizes parametric tangential velocity models derived from Doppler radar measurements, to- gether with a tangential momentum and mass continuity constraint, to esti- mate the radial and vertical velocities in a steady axisymmetric frame. The main result is that information from observations aloft can be extrapolated into the surface layer of the vortex. The impact of the amount of information available to the retrieval is demonstrated through some numerical tests with pseudo-data.

  1. Improved system for measuring speed of rotating machinery

    Science.gov (United States)

    Smith, E. G.

    1972-01-01

    Gear designed with spaces for 61 or 62 teeth but having 1- or 2-tooth gap provides reference point that can be detected electronically and retains convenient count of 60 per revolution obviating need for duplicate electronic equipment.

  2. Model of a rotating magnetic cloud

    Science.gov (United States)

    Farrugia, C. J.; Osherovich, V. A.; Burlaga, L. F.

    1992-01-01

    The possibility that magnetic clouds rotate while they propagate antisunward was investigated. Magnetic clouds are modeled as magnetic flux ropes which rotate rigidly about the axis of symmetry. An ideal magnetohydrodynamic model, in which the evolution of the magnetic structure is related to the time evolution of the angular frequency, is developed. A class of 'separable' magnetic fields is employed to reduce the problem to a nonlinear ordinary differential equation for the evolution function, and it is solved numerically. The corresponding effective potential gives rise to two modes of evolution--expansion and oscillation--depending on the energy and on the value of a dimensionless parameter, k. Parameter k depends on the gas pressure, the ratio of the magnetic field components, and the frequency of rotation. There is a critical value of k, k(sub c), above which the oscillatory regime disappears and the flux rope invariably expands, regardless of the energy. Below k(sub c) the energy determines whether the configuration is confined or unbounded. Rotation always helps expansion by lowering the potential barrier. A data example was studied and features which are interpreted as signatures of rotation are presented. The angular speed is comparable to the Alfven speed, and the core of the rotating cloud completes on average one full revolution every three days at 1 AU. The parameter k is calculated from observations, and it is found to be close to, but below, critical. Only three out of the nine clouds examined showed signatures of rotation. Theoretical analysis suggests that close to the Sun rotation effects may play a more important role in the evolution of magnetic clouds than 1 AU.

  3. Development and testing of an integrated rotating dynamometer on tool holder for milling process

    Science.gov (United States)

    Rizal, Muhammad; Ghani, Jaharah A.; Nuawi, Mohd Zaki; Che Haron, Che Hassan

    2015-02-01

    The cutting force provides significant information to help understand the machining process, optimization, tool condition monitoring, tool design and others. Hence, various methods of measuring the cutting force have been proposed by many researchers. In this work, an innovative integrated rotating dynamometer and tool holder is designed, constructed and tested that can fulfil the requirement to measure the cutting force in a wireless environment system. The device consists of a strain gauge based sensor that is mounted on a newly designed force sensing element which is then placed in the rotating tool holder. The force sensing element is designed in the form of a symmetrical cross beam type with four arms, shaped as a rectangular parallelepiped. This device is intended to be used in a rotating spindle such as in milling and drilling processes. A conditioning system and an inductive telemetry transmitter unit are incorporated into a modified tool holder in order to collect and transmit the cutting force signal to the data acquisition system. The rotating dynamometer has been subjected to a series of tests to determine its static and dynamic characteristics. Thus, it is tested experimentally by conducting cutting tests up to cutting speed 550 m/min with a single-tool insert. The results show it is suitable and reliable to measure the cutting force in milling processes.

  4. Microbial acetate oxidation in horizontal rotating tubular bioreactor

    Indian Academy of Sciences (India)

    A Slavica; B Šantek; S Novak; V Marić

    2004-06-01

    The aim of this work was to investigate the possibility of conducting a continuous aerobic bioprocess in a horizontal rotating tubular bioreactor (HRTB). Aerobic oxidation of acetate by the action of a mixed microbial culture was chosen as a model process. The microbial culture was not only grown in a suspension but also in the form of a biofilm on the interior surface of HRTB. Efficiency of the bioprocess was monitored by determination of the acetate concentration and chemical oxygen demand (COD). While acetate inlet concentration and feeding rate influenced efficiency of acetate oxidation, the bioreactor rotation speed did not influence the bioprocess dynamics significantly. Gradients of acetate concentration and pH along HRTB were more pronounced at lower feeding rates. Volumetric load of acetate was proved to be the most significant parameter. High volumetric loads (above 2 g acetate l–1 h–1) gave poor acetate oxidation efficiency (only 17 to 50%). When the volumetric load was in the range of 0.60–1.75 g acetate l–1 h–1, acetate oxidation efficiency was 50–75%. At lower volumetric loads (0.14–0.58 g acetate l–1 h–1), complete acetate consumption was achieved. On the basis of the obtained results, it can be concluded that HRTB is suitable for conducting aerobic continuous bioprocesses.

  5. Experimental study of a rotating packed bed distillation column

    Directory of Open Access Journals (Sweden)

    J. V. S. Nascimento

    2009-03-01

    Full Text Available The purpose of this work was to study the mass transfer performance of rotating packed beds applying the "Higee" process. The operations were carried out with the n-hexane/n-heptane distilling system at atmospheric pressure and under total reflux conditions. The rotating speed could be varied between 300 and 2500 rpm, which provided centrifugal forces from 5 to 316 times the Earth's gravity. The effects of concentration, vapor velocity, rotating speed and packing type (two different Raschig ring sizes and structured wire mesh packing on mass transfer behavior were analyzed. Experimental results showed that the mass transfer coefficient depends on the liquid flow rates and rotating speed. The equipment had high separation efficiency in a reduced bed volume.

  6. Physics of Rotating and Expanding Black Hole Universe

    Directory of Open Access Journals (Sweden)

    Seshavatharam U. V. S.

    2010-04-01

    Full Text Available Throughout its journey universe follows strong gravity. By unifying general theory of relativity and quantum mechanics a simple derivation is given for rotating black hole's temperature. It is shown that when the rotation speed approaches light speed temperature approaches Hawking's black hole temperature. Applying this idea to the cosmic black hole it is noticed that there is "no cosmic temperature" if there is "no cosmic rotation". Starting from the Planck scale it is assumed that universe is a rotating and expanding black hole. Another key assumption is that at any time cosmic black hole rotates with light speed. For this cosmic sphere as a whole while in light speed rotation "rate of decrease" in temperature or "rate of increase" in cosmic red shift is a measure of "rate of cosmic expansion". Since 1992, measured CMBR data indicates that, present CMB is same in all directions equal to $2.726^circ$ K, smooth to 1 part in 100,000 and there is no continuous decrease! This directly indicates that, at present rate of decrease in temperature is practically zero and rate of expansion is practically zero. Universe is isotropic and hence static and is rotating as a rigid sphere with light speed. At present galaxies are revolving with speeds proportional to their distances from the cosmic axis of rotation. If present CMBR temperature is $2.726^circ$ K, present value of obtained angular velocity is $2.17 imes 10^{-18}$ rad/sec $cong$ 67 Km/sec$imes$Mpc. Present cosmic mass density and cosmic time are fitted with a $ln (volume ratio$ parameter. Finally it can be suggested that dark matter and dark energy are ad-hoc and misleading concepts.

  7. On the fast magnetic rotator regime of stellar winds

    Science.gov (United States)

    Johnstone, C. P.

    2017-01-01

    Aims: We study the acceleration of the stellar winds of rapidly rotating low mass stars and the transition between the slow magnetic rotator and fast magnetic rotator regimes. We aim to understand the properties of stellar winds in the fast magnetic rotator regime and the effects of magneto-centrifugal forces on wind speeds and mass loss rates. Methods: We extend a solar wind model to 1D magnetohydrodynamic simulations of the winds of rotating stars. We test two assumptions for how to scale the wind temperature to other stars and assume the mass loss rate scales as dot{M_star ∝ R_star2 Ω_star1.33 M_star-3.36}, in the unsaturated regime, as estimated from observed rotational evolution. Results: For 1.0 M⊙ stars, the winds can be accelerated to several thousand km s-1, and the effects of magneto-centrifugal forces are much weaker for lower mass stars. We find that the different assumptions for how to scale the wind temperature to other stars lead to significantly different mass loss rates for the rapid rotators. If we assume a constant temperature, the mass loss rates of solar mass stars do not saturate at rapid rotation, which we show to be inconsistent with observed rotational evolution. If we assume the wind temperatures scale positively with rotation, the mass loss rates are only influenced significantly at rotation rates above 75 Ω⊙. We suggest that models with increasing wind speed for more rapid rotators are preferable to those that assume a constant wind speed. If this conclusion is confirmed by more sophisticated wind modelling. it might provide an interesting observational constraint on the properties of stellar winds. All of the codes and output data used in this paper can be downloaded from http://https://zenodo.org/record/160052#.V_y6drWkVC1 or obtained by contacting the author.

  8. Rotator cuff repair - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100229.htm Rotator cuff repair - series—Normal anatomy To use the sharing ... to slide 4 out of 4 Overview The rotator cuff is a group of muscles and tendons that ...

  9. Discriminating the structure of rotated three-dimensional figures.

    Science.gov (United States)

    Barfield, W; Salvendy, G

    1987-10-01

    Visualizing the structure of transformed (by rotation) three-dimensional (3-D) figures is an important aspect of information processing for computer-graphics tasks. However, little research exists to establish the speed and accuracy in which subjects perform discrimination tasks for transformed images and the effects of rotation variables on perceiving transformed images. This research tests the effects of figural complexity, angles and axes of rotation on the speed and accuracy in which subjects discriminate the structure of rotated 3-D wireframe images. Results show that response times are affected more by angles than axes of rotation, the specific form of the image affects error rates, and the number of 90 degrees bends which determine the structure of an image may be an inadequate measure of form complexity for the task described here.

  10. Numerical simulation of negative Magnus force on a rotating sphere

    Science.gov (United States)

    Muto, Masaya; Tsubokura, Makoto; Oshima, Nobuyuki

    2010-11-01

    Flow characteristics and fluid force on a sphere rotating along with axis perpendicular to mean air flow were investigated using Large Eddy Simulation at two different Reynolds numbers of 10,000 and 200,000. As a result of simulation, opposite flow characteristics around the sphere and displacement of the separation point were visualized depending on the Reynolds number even though the sphere rotates at the same rotation speed according to the Reynolds number. When Reynolds number is 10,000, flow characteristics agree with the flow field explained in the Magnus effect. However sphere rotates at the same rotation speed while increasing Reynolds number to 200,000, separation point moves in opposite direction and wake appears in the different direction. The reason of the negative Magnus force was discussed in terms of the boundary layer transition on the surface.

  11. Fault Diagnosis for Rotating Machinery: A Method based on Image Processing.

    Science.gov (United States)

    Lu, Chen; Wang, Yang; Ragulskis, Minvydas; Cheng, Yujie

    2016-01-01

    Rotating machinery is one of the most typical types of mechanical equipment and plays a significant role in industrial applications. Condition monitoring and fault diagnosis of rotating machinery has gained wide attention for its significance in preventing catastrophic accident and guaranteeing sufficient maintenance. With the development of science and technology, fault diagnosis methods based on multi-disciplines are becoming the focus in the field of fault diagnosis of rotating machinery. This paper presents a multi-discipline method based on image-processing for fault diagnosis of rotating machinery. Different from traditional analysis method in one-dimensional space, this study employs computing method in the field of image processing to realize automatic feature extraction and fault diagnosis in a two-dimensional space. The proposed method mainly includes the following steps. First, the vibration signal is transformed into a bi-spectrum contour map utilizing bi-spectrum technology, which provides a basis for the following image-based feature extraction. Then, an emerging approach in the field of image processing for feature extraction, speeded-up robust features, is employed to automatically exact fault features from the transformed bi-spectrum contour map and finally form a high-dimensional feature vector. To reduce the dimensionality of the feature vector, thus highlighting main fault features and reducing subsequent computing resources, t-Distributed Stochastic Neighbor Embedding is adopt to reduce the dimensionality of the feature vector. At last, probabilistic neural network is introduced for fault identification. Two typical rotating machinery, axial piston hydraulic pump and self-priming centrifugal pumps, are selected to demonstrate the effectiveness of the proposed method. Results show that the proposed method based on image-processing achieves a high accuracy, thus providing a highly effective means to fault diagnosis for rotating machinery.

  12. Fault Diagnosis for Rotating Machinery: A Method based on Image Processing

    Science.gov (United States)

    Lu, Chen; Wang, Yang; Ragulskis, Minvydas; Cheng, Yujie

    2016-01-01

    Rotating machinery is one of the most typical types of mechanical equipment and plays a significant role in industrial applications. Condition monitoring and fault diagnosis of rotating machinery has gained wide attention for its significance in preventing catastrophic accident and guaranteeing sufficient maintenance. With the development of science and technology, fault diagnosis methods based on multi-disciplines are becoming the focus in the field of fault diagnosis of rotating machinery. This paper presents a multi-discipline method based on image-processing for fault diagnosis of rotating machinery. Different from traditional analysis method in one-dimensional space, this study employs computing method in the field of image processing to realize automatic feature extraction and fault diagnosis in a two-dimensional space. The proposed method mainly includes the following steps. First, the vibration signal is transformed into a bi-spectrum contour map utilizing bi-spectrum technology, which provides a basis for the following image-based feature extraction. Then, an emerging approach in the field of image processing for feature extraction, speeded-up robust features, is employed to automatically exact fault features from the transformed bi-spectrum contour map and finally form a high-dimensional feature vector. To reduce the dimensionality of the feature vector, thus highlighting main fault features and reducing subsequent computing resources, t-Distributed Stochastic Neighbor Embedding is adopt to reduce the dimensionality of the feature vector. At last, probabilistic neural network is introduced for fault identification. Two typical rotating machinery, axial piston hydraulic pump and self-priming centrifugal pumps, are selected to demonstrate the effectiveness of the proposed method. Results show that the proposed method based on image-processing achieves a high accuracy, thus providing a highly effective means to fault diagnosis for rotating machinery. PMID

  13. Pitching Speed and Glenohumeral Adaptation in High School Pitchers.

    Science.gov (United States)

    Keller, Robert A; Marshall, Nathan E; Mehran, Nima; Moutzouros, Vasilios

    2015-08-01

    Glenohumeral internal rotational deficit and increased glenohumeral external rotation are common findings in baseball pitchers. To the authors' knowledge, no study has focused on the adaptation of glenohumeral internal rotational deficit and increased glenohumeral external rotation in relation to pitching speed. This study evaluated changes in range of motion in the throwing shoulder in high school pitchers to determine whether changes in internal and external rotation directly correlate with pitch velocity. The shoulders of 22 high school varsity pitchers were evaluated. Standard goniometric technique was used to measure passive external and internal glenohumeral range of motion in both arms. Measurements were evaluated for statistically significant differences in range of motion. Demographic features, including height, weight, and age, were assessed. Fifteen consecutive in-game pitch speeds were recorded, and the fastest pitch was used for evaluation. Pitch speeds were correlated to the player's glenohumeral internal rotational deficit, increased glenohumeral external rotation, and physical demographics. Average age was 16.9 years. Average external rotation of the throwing arm was significantly greater than that of the nonthrowing arm (143.00° vs 130.32°, P=.005). Average internal rotation of the throwing arm was significantly less than that of the nonthrowing arm (49.50° vs 65.90°, P=.006). Both shoulders had similar total arc of motion (throwing shoulder, 192.54; nonthrowing shoulder, 196.23; P=.822). Average maximum velocity was 77.7 mph (maximum, 88 mph; minimum, 66 mph). Maximum pitch velocity did not correlate with changes in glenohumeral internal rotational deficit (P=.683) or increased glenohumeral external rotation (P=.241). There was also no evidence of correlation between pitch velocity and player age, height, weight, or dominant hand. The stress of pitching creates adaptations to the throwing shoulder, even in young athletes. There appears to be

  14. On Averaging Rotations

    DEFF Research Database (Denmark)

    Gramkow, Claus

    1999-01-01

    In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...... approximations to the Riemannian metric, and that the subsequent corrections are inherient in the least squares estimation. Keywords: averaging rotations, Riemannian metric, matrix, quaternion...

  15. Rotations with Rodrigues' Vector

    Science.gov (United States)

    Pina, E.

    2011-01-01

    The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears…

  16. On Averaging Rotations

    DEFF Research Database (Denmark)

    Gramkow, Claus

    2001-01-01

    In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

  17. The Application of Counter-Rotating Turbine in Rocket Turbopump

    Directory of Open Access Journals (Sweden)

    Tang Fei

    2008-01-01

    Full Text Available Counter rotating turbine offers advantages on weight, volume, efficiency, and maneuverability relative to the conventional turbine because of its special architecture. Nowadays, it has been a worldwide research emphasis and has been used widely in the aeronautic field, while its application in the astronautic field is seldom investigated. Researches of counter rotating turbine for rocket turbopump are reviewed in this paper. A primary analysis of a vaneless counter rotating-turbine configuration with rotors of different diameters and rotational speeds is presented. This unconventional configuration meets the requirements of turbopump and may benefit the performance and reliability of rocket engines.

  18. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    Directory of Open Access Journals (Sweden)

    Yanting Hu

    2013-07-01

    Full Text Available Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG developed in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated. The 3p (three times per revolution power oscillation due to wind shear and tower shadow effects is the significant part in the flicker emission of variable speed wind turbines with PMSG during continuous operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.

  19. Speed in Acquisitions

    DEFF Research Database (Denmark)

    Meglio, Olimpia; King, David R.; Risberg, Annette

    2017-01-01

    The advantage of speed is often invoked by academics and practitioners as an essential condition during post-acquisition integration, frequently without consideration of the impact earlier decisions have on acquisition speed. In this article, we examine the role speed plays in acquisitions across...... the acquisition process using research organized around characteristics that display complexity with respect to acquisition speed. We incorporate existing research with a process perspective of acquisitions in order to present trade-offs, and consider the influence of both stakeholders and the pre......-deal-completion context on acquisition speed, as well as the organization’s capabilities to facilitating that speed. Observed trade-offs suggest both that acquisition speed often requires longer planning time before an acquisition and that associated decisions require managerial judgement. A framework for improving...

  20. Condition Monitoring of Forward Curved Centrifugal Blower Using Coast Down Time Analysis

    Directory of Open Access Journals (Sweden)

    G. R. Rameshkumar

    2010-01-01

    Full Text Available Mechanical malfunctions such as, rotor unbalance and shaft misalignment are the most common causes of vibration in rotating machineries. Vibration is the most widely used parameter to monitor and asses the machine health condition. In this work, the Coast Down Time (CDT, which is an indicator of faults, is used to assess the condition of the rotating machine as a condition monitoring parameter. CDT is the total time taken by the system to dissipate the momentum acquired during sustained operation. Extensive experiments were conducted on Forward Curved Centrifugal Blower Test Rig at selected cutoff speeds for several combinations of combined horizontal and vertical parallel misalignment, combined parallel and angular misalignment, as well as for various unbalance conditions. As mechanical faults increase, a drastic decrease in CDT is found and this is represented as CDT reduction percentage. A specific correlation between the CDT reduction percentage, level of mechanical faults, and rotational cutoff speeds is observed. The results are analyzed and compared with vibration analysis for potential use of CDT as one of the condition monitoring parameter.

  1. Predictors of human rotation.

    Science.gov (United States)

    Stochl, Jan; Croudace, Tim

    2013-01-01

    Why some humans prefer to rotate clockwise rather than anticlockwise is not well understood. This study aims to identify the predictors of the preferred rotation direction in humans. The variables hypothesised to influence rotation preference include handedness, footedness, sex, brain hemisphere lateralisation, and the Coriolis effect (which results from geospatial location on the Earth). An online questionnaire allowed us to analyse data from 1526 respondents in 97 countries. Factor analysis showed that the direction of rotation should be studied separately for local and global movements. Handedness, footedness, and the item hypothesised to measure brain hemisphere lateralisation are predictors of rotation direction for both global and local movements. Sex is a predictor of the direction of global rotation movements but not local ones, and both sexes tend to rotate clockwise. Geospatial location does not predict the preferred direction of rotation. Our study confirms previous findings concerning the influence of handedness, footedness, and sex on human rotation; our study also provides new insight into the underlying structure of human rotation movements and excludes the Coriolis effect as a predictor of rotation.

  2. The spatial rotator

    DEFF Research Database (Denmark)

    Rasmusson, Allan; Hahn, Ute; Larsen, Jytte Overgaard

    2013-01-01

    to identify the specific tissue region under study. In order to use the spatial rotator in practice, however, it is necessary to be able to identify intersection points between cell boundaries and test rays in a series of parallel focal planes, also at the peripheral parts of the cell boundaries. In cases......This paper presents a new local volume estimator, the spatial rotator, which is based on measurements on a virtual 3D probe, using computer assisted microscopy. The basic design of the probe builds upon the rotator principle which requires only a few manual intersection markings, thus making...... the spatial rotator fast to use. Since a 3D probe is involved, it is expected that the spatial rotator will be more efficient than the the nucleator and the planar rotator, which are based on measurements in a single plane. An extensive simulation study shows that the spatial rotator may be more efficient...

  3. Physics of Rotating and Expanding Black Hole Universe

    Directory of Open Access Journals (Sweden)

    Seshavatharam U. V. S.

    2010-04-01

    Full Text Available Throughout its journey universe follows strong gravity. By unifying general theory of relativity and quantum mechanics a simple derivation is given for rotating black hole’s temperature. It is shown that when the rotation speed approaches light speed temperature approaches Hawking’s black hole temperature. Applying this idea to the cosmic black hole it is noticed that there is “no cosmic temperature” if there is “no cosmic rotation”. Starting from the Planck scale it is assumed that- universe is a rotating and expanding black hole. Another key assumption is that at any time cosmic black hole rotates with light speed. For this cosmic sphere as a whole while in light speed rotation “rate of decrease” in temperature or “rate of increase” in cosmic red shift is a measure of “rate of cosmic expansion”. Since 1992, measured CMBR data indicates that, present CMB is same in all directions equal to 2 : 726 K ; smooth to 1 part in 100,000 and there is no continuous decrease! This directly indicates that, at present rate of decrease in temperature is practically zero and rate of expansion is practically zero. Universe is isotropic and hence static and is rotating as a rigid sphere with light speed. At present galaxies are revolving with speeds proportional to their distances from the cosmic axis of rotation. If present CMBR temperature is 2 : 726 K, present value of obtained angular velocity is 2 : 17 10 Present cosmic mass density and cosmic time are fitted with a ln ( volume ratio parameter. Finally it can be suggested that dark matter and dark energy are ad-hoc and misleading concepts.

  4. Properties of the flow around two rotating circular cylinders in side-by-side arrangement with different rotation types

    Directory of Open Access Journals (Sweden)

    Tu Cheng-Xu

    2014-01-01

    Full Text Available The field characteristics of two side-by-side rotating circular cylinders in a cross-flow is investigated under different rotation types, at T/D = 1.11,1.6, and 3, respectively (T is the center spacing between the cylinders, and D is the cylinder diameter. A similar flow pattern which is the most efficient to narrow the lowpressure area is identified for rotation type A, independent of T/D ratio, and two typical flow patterns are found under different spacings for rotation type B and type C, respectively. It is confirmed that there is an optimal rotational speed of 1.7-2, under rotation type A to attenuate the vortices, velocity drop, and turbulence intensity tremendously. As rotational speed increases to the optimal value, both the velocity drop and turbulence intensity decrease and their distributions are smooth. The results indicate that the shear layers which are accelerated following the free-stream direction would have significant influence on the flow modification, and different rotation types actually arrange these shear layers in diverse ways to change the flow pattern. Pitch ratio is capable to transform the gap flow, which is usually including the shear layers referred, thus this parameter can modify the wake of the two cylinders at different rotation types.

  5. Rotational Doppler effect in nonlinear optics

    Science.gov (United States)

    Li, Guixin; Zentgraf, Thomas; Zhang, Shuang

    2016-08-01

    The translational Doppler effect of electromagnetic and sound waves has been successfully applied in measurements of the speed and direction of vehicles, astronomical objects and blood flow in human bodies, and for the Global Positioning System. The Doppler effect plays a key role for some important quantum phenomena such as the broadened emission spectra of atoms and has benefited cooling and trapping of atoms with laser light. Despite numerous successful applications of the translational Doppler effect, it fails to measure the rotation frequency of a spinning object when the probing wave propagates along its rotation axis. This constraint was circumvented by deploying the angular momentum of electromagnetic waves--the so-called rotational Doppler effect. Here, we report on the demonstration of rotational Doppler shift in nonlinear optics. The Doppler frequency shift is determined for the second harmonic generation of a circularly polarized beam passing through a spinning nonlinear optical crystal with three-fold rotational symmetry. We find that the second harmonic generation signal with circular polarization opposite to that of the fundamental beam experiences a Doppler shift of three times the rotation frequency of the optical crystal. This demonstration is of fundamental significance in nonlinear optics, as it provides us with insight into the interaction of light with moving media in the nonlinear optical regime.

  6. Condition monitoring of gearboxes using synchronously averaged electric motor signals

    Science.gov (United States)

    Ottewill, J. R.; Orkisz, M.

    2013-07-01

    Due to their prevalence in rotating machinery, the condition monitoring of gearboxes is extremely important in the minimization of potentially dangerous and expensive failures. Traditionally, gearbox condition monitoring has been conducted using measurements obtained from casing-mounted vibration transducers such as accelerometers. A well-established technique for analyzing such signals is the synchronous signal average, where vibration signals are synchronized to a measured angular position and then averaged from rotation to rotation. Driven, in part, by improvements in control methodologies based upon methods of estimating rotor speed and torque, induction machines are used increasingly in industry to drive rotating machinery. As a result, attempts have been made to diagnose defects using measured terminal currents and voltages. In this paper, the application of the synchronous signal averaging methodology to electric drive signals, by synchronizing stator current signals with a shaft position estimated from current and voltage measurements is proposed. Initially, a test-rig is introduced based on an induction motor driving a two-stage reduction gearbox which is loaded by a DC motor. It is shown that a defect seeded into the gearbox may be located using signals acquired from casing-mounted accelerometers and shaft mounted encoders. Using simple models of an induction motor and a gearbox, it is shown that it should be possible to observe gearbox defects in the measured stator current signal. A robust method of extracting the average speed of a machine from the current frequency spectrum, based on the location of sidebands of the power supply frequency due to rotor eccentricity, is presented. The synchronous signal averaging method is applied to the resulting estimations of rotor position and torsional vibration. Experimental results show that the method is extremely adept at locating gear tooth defects. Further results, considering different loads and different

  7. Galaxy cluster's rotation

    CERN Document Server

    Manolopoulou, Maria

    2016-01-01

    We study the possible rotation of cluster galaxies, developing, testing and applying a novel algorithm which identifies rotation, if such does exits, as well as its rotational centre, its axis orientation, rotational velocity amplitude and, finally, the clockwise or counterclockwise direction of rotation on the plane of the sky. To validate our algorithms we construct realistic Monte-Carlo mock rotating clusters and confirm that our method provides robust indications of rotation. We then apply our methodology on a sample of Abell clusters with z<~0.1 with member galaxies selected from the SDSS DR10 spectroscopic database. We find that ~35% of our clusters are rotating when using a set of strict criteria, while loosening the criteria we find this fraction increasing to ~48%. We correlate our rotation indicators with the cluster dynamical state, provided either by their Bautz-Morgan type or by their X-ray isophotal shape and find for those clusters showing rotation that the significance and strength of their...

  8. Electro-mechanical coupling of rotating 3D beams

    Directory of Open Access Journals (Sweden)

    Stoykov S.

    2016-01-01

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

  9. Design and application on experimental platform for high-speed bearing with grease lubrication

    Directory of Open Access Journals (Sweden)

    He Qiang

    2015-12-01

    Full Text Available The experimental platform for high-speed grease is an important tool for research and development of high-speed motorized spindle with grease lubrication. In this article, the experimental platform for high-speed grease is designed and manufactured which consists of the drive system, the test portion, the loading system, the lubrication system, the control system, and so on. In the meantime, the high-speed angular contact ceramic ball bearings B7005C/HQ1P4 as the research object are tested and contrasted in the grease lubrication and oil mist lubrication. The experimental platform performance is validated by contrast experiment, and the high-speed lubricated bearing performance is also studied especially in the relationship among the rotating speed,load and temperature rise. The results show that the experimental platform works steadily, accurate, and reliable in the experimental testing. And the grease lubrication ceramic ball bearings B7005C/HQ1P4 can be used in high-speed motorized spindle in the circular water cooling conditions when the rotating speed is lower than 40,000 r/min or the DN value (the value of the bearing diameter times the rotating speed is lower than the 1.44 × 106 mm r/min. Grease lubrication instead of oil mist lubrication under high-speed rotating will simplify the structure design of the high-speed motorized spindle and reduce the pollution to the environment.

  10. Continuous monitoring methods for assessment of structural integrity in nuclear power plants; Jatkuvan monitoroinnin menetelmaet rakenteiden eheyden varmistamiseen ydinvoimaloissa

    Energy Technology Data Exchange (ETDEWEB)

    Sarkimo, M.

    1998-01-01

    This report is a review of the frequently used continuous monitoring methods that are applied or can possibly be applied in nuclear power plants. The methods covered include condition monitoring and non-destructive testing (NDT) techniques that can be used to detect flaws in components and the malfunction of machinery. The specific techniques for water chemistry monitoring are not covered by this report. The systems based on acoustic emission are considered to be suitable for continuous monitoring applications and these are discussed in greater detail compared to other methods. The loose parts monitoring and leak detection systems based on acoustic emission have practical applications in several nuclear power plants. The real-time monitoring of crack-tip movement using the ultrasonic method is also discussed. Some results are also referred to from the research and development work to monitor crack initiation and growth on the surface of high-speed rotating components using the electromagnetic method. Vibration measurements and analysis are mentioned as a usual tool for monitoring the condition of rotating machinery but also some special aspects of nuclear power plants are included. Finally the on-line fatigue and integrity monitoring systems are briefly discussed and given some considerations regarding the material property measurements using continuous non-destructive methods. (orig.). 34 refs.

  11. Continuous monitoring methods for assessment of structural integrity in nuclear power plants; Jatkuvan monitoroinnin menetelmaet rakenteiden eheyden varmistamiseen ydinvoimaloissa

    Energy Technology Data Exchange (ETDEWEB)

    Sarkimo, M.

    1998-01-01

    This report is a review of the frequently used continuous monitoring methods that are applied or can possibly be applied in nuclear power plants. The methods covered include condition monitoring and non-destructive testing (NDT) techniques that can be used to detect flaws in components and the malfunction of machinery. The specific techniques for water chemistry monitoring are not covered by this report. The systems based on acoustic emission are considered to be suitable for continuous monitoring applications and these are discussed in greater detail compared to other methods. The loose parts monitoring and leak detection systems based on acoustic emission have practical applications in several nuclear power plants. The real-time monitoring of crack-tip movement using the ultrasonic method is also discussed. Some results are also referred to from the research and development work to monitor crack initiation and growth on the surface of high-speed rotating components using the electromagnetic method. Vibration measurements and analysis are mentioned as a usual tool for monitoring the condition of rotating machinery but also some special aspects of nuclear power plants are included. Finally the on-line fatigue and integrity monitoring systems are briefly discussed and given some considerations regarding the material property measurements using continuous non-destructive methods. (orig.). 34 refs.

  12. Dynamic balancing with rotating radial electromagnetic force

    Institute of Scientific and Technical Information of China (English)

    李勇; 陆永平

    2004-01-01

    A method of producing rotating radial electromagnetic force with a separable structure is proposed,and an experimental model was designed on which open loop vibration control experiments were carried out. Experimental results prove that the electromagnetic force designed has a constant magnitude and an uniform speed,and the idea of using an electromagnetic force as an active control in automatic balancing is correct in principle,and practicable in engineering.

  13. 46 CFR 154.1864 - Vessel speed within speed reduction.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Vessel speed within speed reduction. 154.1864 Section... Vessel speed within speed reduction. The master shall ensure that the speed of the vessel is not greater than the posted speed reduction....

  14. Rotating target wheel for the FMA

    Energy Technology Data Exchange (ETDEWEB)

    Back, B.B.; Davids, C.N.; Falout, J. [and others

    1995-08-01

    In anticipation of high intensity beams that will be available from the PII-ECR source injector to ATLAS, a new rotating target wheel was developed for the sliding seal chamber at the FMA. The wheel is 9 inch in diameter and contains up to ten targets. The rotation of the wheel is achieved by a DC motor, a ferrofluidic feedthrough, and a gear mechanism that allows both target rotation and changing the target angle relative to the beam. The nominal rotation speed is 1000 RPM, although higher speeds can be achieved if necessary. The assembly is equipped with an absolute encoder which is read out via a newly developed CAMAC module. This module provides the following main functions: (1) a TTL signal to be used for sweeping the beam when a target frame is about to pass through the beam, (2) a read-out of the target position that can be included in the data event structure, (3) programmable set points for the beam-off signal. The system is presently being tested and will be used in experiments scheduled for March 1995.

  15. Detection of fatigue crack on a rotating steel shaft using air-coupled nonlinear ultrasonic modulation

    Science.gov (United States)

    Song, Byeongju; Park, Byeongjin; Sohn, Hoon; Lim, Cheol-Woo; Park, Jae-Roung

    2015-04-01

    Rotating shafts in drop lifts of manufacturing facilities are susceptible to fatigue cracks as they are under repetitive heavy loading and high speed spins. However, it is challenging to use conventional contact transducers to monitor these shafts as they are continuously spinning with a high speed. In this study, a noncontact crack detection technique for a rotating shaft is proposed using air-coupled transducers (ACTs). (1) Low frequency (LF) and high frequency (HF) sinusoidal inputs are simultaneously applied to a shaft using two ACTs, respectively. A fatigue crack can provide a mechanism for nonlinear ultrasonic modulation and create spectral sidebands at the modulation frequencies, which are the sum and difference of the two input frequencies Then LF and HF inputs are independently applied to the shaft using each ACT. These three ultrasonic responses are measured using another ACT. (2) The damage index (DI) is defined as the energy of the first sideband components, which corresponding to the frequency sum and difference between HF and LF inputs. (3) Steps 1 and 2 are repeated with various combinations of HF and LF inputs. Crack existence is detected through an outlier analysis of the DIs. The effectiveness of the proposed technique is investigated using a steel shaft with a real fatigue crack.

  16. Avaliação da temperatura desenvolvida durante a remoção de pino intra-radicular, com instrumentos cortantes rotatórios em alta rotação Evaluation of the temperature generated during the removal of posts with burs in high speed handpiece

    Directory of Open Access Journals (Sweden)

    Tomie Nakakuki de CAMPOS

    1998-07-01

    Full Text Available Com a preocupação de avaliar os efeitos danosos da transmissão de calor aos tecidos periodontais, este trabalho teve como objetivo avaliar a temperatura gerada durante a remoção de pinos intra-radiculares com o uso de instrumentos cortantes rotatórios (ICR em alta rotação. Para se obter os registros da temperatura durante os desgastes, foram fixados fios termopares ao redor do terço médio e terço apical da raiz de incisivos centrais superiores extraídos, conectados a termômetros digitais. Através da análise de variância, verificou-se que houve diferença estatisticamente significante, de 5%, entre as regiões medidas e as ligas utilizadas. Analisando as regiões, observou-se, na região mediana, amplitude de 9,1oC, e, na região apical, amplitude de 6,2oC. A liga de CuAlZn (GOLDENT alcançou média de amplitude maior, 10,3oC, as ligas de CuAl (DURACAST, 6,3oC, e a de PdAg (PORS-ON 4, 6,3oC. Provavelmente, os fatores que interferiram foram o grau de refrigeração, a pressão e o corte intermitente. Baseando-se na metodologia utilizada, concluiu-se que a remoção de pinos intra-radiculares, através do uso de ICR em alta rotação, pode gerar amplitudes de temperatura críticas de acordo com a região do desgaste e liga utilizada.Due to the concern with the damaging effects of heat distribution on periodontal tissues, this study had the objective of evaluating the temperature generated during the removal of posts with burs in high speed handpieces. Fixed thermopars around the medium and apical regions of the roots of extracted superior central incisors, connected to digital thermometers, were used to obtain temperature measurements during wearing down. Analysis of variance demonstrated a statistically significant difference, to the level of 5%, between the regions where the temperature was taken and the alloys used. When comparing the differences between the regions of roots, the medium portion presented a variation of 9.1oC, and

  17. Interplay between intrinsic plasma rotation and magnetic island evolution in disruptive discharges

    Science.gov (United States)

    Ronchi, G.; Severo, J. H. F.; Salzedas, F.; Galvão, R. M. O.; Sanada, E. K.

    2016-05-01

    The behavior of the intrinsic toroidal rotation of the plasma column during the growth and eventual saturation of m/ n = 2/1 magnetic islands, triggered by programmed density rise, has been carefully investigated in disruptive discharges in TCABR. The results show that, as the island starts to grow and rotate at a speed larger than that of the plasma column, the angular frequency of the intrinsic toroidal rotation increases and that of the island decreases, following the expectation of synchronization. As the island saturates at a large size, just before a major disruption, the angular speed of the intrinsic rotation decreases quite rapidly, even though the island keeps still rotating at a reduced speed. This decrease of the toroidal rotation is quite reproducible and can be considered as an indicative of disruption.

  18. Relativistic Rotating Vector Model

    CERN Document Server

    Lyutikov, Maxim

    2016-01-01

    The direction of polarization produced by a moving source rotates with the respect to the rest frame. We show that this effect, induced by pulsar rotation, leads to an important correction to polarization swings within the framework of rotating vector model (RVM); this effect has been missed by previous works. We construct relativistic RVM taking into account finite heights of the emission region that lead to aberration, time-of-travel effects and relativistic rotation of polarization. Polarizations swings at different frequencies can be used, within the assumption of the radius-to-frequency mapping, to infer emission radii and geometry of pulsars.

  19. Vibration of imperfect rotating disk

    Directory of Open Access Journals (Sweden)

    Půst L.

    2011-12-01

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

  20. Digital monitoring and health diagnosis for mechanical equipment operation safety based on fiber Bragg grating sensor

    Institute of Scientific and Technical Information of China (English)

    Zude ZHOU; Desheng JIANG; Quan LIU

    2009-01-01

    This paper introduces fiber Bragg grating (FBG) based on a fiber optic grating sensor developed to be embedded on mechanical equipment for digital monitoring and health diagnosis. The theoretical and experimental researches on the new-style FBG sensor (FBGS) technology, high-speed demodulation, and data transmission are discussed. The transmission characteristics between the FBG and the detection interface, modeling and compensation method for online distributed multi-parameter digital monitoring and methods for data processing, synchronous sampling, and long-term dynamic digital monitoring using embedded technology are also presented. The acquired information by an FBGS can be used for the optimization of maintenance schedules and refinement of mechanical equipment design. It is a chal-lenge to gather real-time data from components working at high speed and in a severe environment of high temperature, high pressure, and high rotation speed. Currently, there are no sensors or technologies available for digital monitoring and health diagnosis under this rigorous situation for use in mechanical engineering operation safety. As a result, this paper introduces an online distributed and integrated digital monitoring system and health diagnosis. The new principle and new method will contribute to modem measurements in science and technology, mechanical engineering, and large mechanical equipment operation safety.

  1. Rotating Snakes Illusion—Quantitative Analysis Reveals a Region in Luminance Space With Opposite Illusory Rotation

    Science.gov (United States)

    Atala-Gérard, Lea

    2017-01-01

    The Rotating Snakes Illusion employs patterns with repetitive asymmetric luminance steps forming a “snake wheel.” In the underlying luminance sequence {black, dark grey, white, light grey}, coded as {0, g1, 100, g2}, we varied g1 and g2 and measured illusion strength via nulling: Saccades were performed next to a “snake wheel” that rotated physically; observers adjusted rotation until a stationary percept obtained. Observers performed the perceptual nulling of the seeming rotation reliably. Typical settings for (g1, g2), measured from images by Kitaoka, are around (20%, 60%). Indeed, we found a marked illusion in the region (g1≈{0%–25%}, g2≈{20%–75%}) with a rotation speed of ≈1°/s. Surprisingly, we detected a second “island” around (70%, 95%) with opposite direction of the illusory rotation and weaker illusion. Our quantitative measurements of illusion strength confirmed the optimal luminance choices of the standard snake wheel and, unexpectedly, revealed an opposite rotation illusion. PMID:28228928

  2. Rotating Snakes Illusion-Quantitative Analysis Reveals a Region in Luminance Space With Opposite Illusory Rotation.

    Science.gov (United States)

    Atala-Gérard, Lea; Bach, Michael

    2017-01-01

    The Rotating Snakes Illusion employs patterns with repetitive asymmetric luminance steps forming a "snake wheel." In the underlying luminance sequence {black, dark grey, white, light grey}, coded as {0, g1, 100, g2}, we varied g1 and g2 and measured illusion strength via nulling: Saccades were performed next to a "snake wheel" that rotated physically; observers adjusted rotation until a stationary percept obtained. Observers performed the perceptual nulling of the seeming rotation reliably. Typical settings for (g1, g2), measured from images by Kitaoka, are around (20%, 60%). Indeed, we found a marked illusion in the region (g1≈{0%-25%}, g2≈{20%-75%}) with a rotation speed of ≈1°/s. Surprisingly, we detected a second "island" around (70%, 95%) with opposite direction of the illusory rotation and weaker illusion. Our quantitative measurements of illusion strength confirmed the optimal luminance choices of the standard snake wheel and, unexpectedly, revealed an opposite rotation illusion.

  3. Dispersive and nonlinear effects in high-speed reconfigurable WDM optical fiber communication systems

    Science.gov (United States)

    Yu, Changyuan

    Chromatic dispersion, polarization mode dispersion (PMD) and nonlinear effects are important issues on the physical layer of high-speed reconfigurable WDM optical fiber communication systems. For beyond 10 Gbit/s optical fiber transmission system, it is essential that chromatic dispersion and PMD be well managed by dispersion monitoring and compensation. One the other hand, dispersive and nonlinear effects in optical fiber systems can also be beneficial and has applications on pulse management, all-optical signal processing and network function, which will be essential for high bite-rate optical networks and replacing the expensive optical-electrical-optical (O/E/O) conversion. In this Ph.D. dissertation, we present a detailed research on dispersive and nonlinear effects in high-speed optical communication systems. We have demonstrated: (i) A novel technique for optically compensating the PMD-induced RF power fading that occurs in single-sideband (SSB) subcarrier-multiplexed systems. By aligning the polarization states of the optical carrier and the SSB, RF power fading due to all orders of PMD can be completely compensated. (ii) Chromatic-dispersion-insensitive PMD monitoring by using a narrowband FBG notch filter to recover the RF clock power for 10Gb/s NRZ data, and apply it as a control signal for PMD compensation. (iii) Chirp-free high-speed optical pulse generation with a repetition rate of 160 GHz (which is four times of the frequency of the electrical clock) using a phase modulator and polarization maintaining (PM) fiber. (iv) Polarization-insensitive all-optical wavelength conversion based on four-wave mixing in dispersion-shifted fiber (DSF) with a fiber Bragg grating and a Faraday rotator mirror. (v) Width-tunable optical RZ pulse train generation based on four-wave mixing in highly-nonlinear fiber. By electrically tuning the delay between two pump pulse trains, the pulse-width of a generated pulse train is continuously tuned. (vi) A high-speed all

  4. Natures of Rotating Stall Cell in a Diagonal Flow Fan

    Institute of Scientific and Technical Information of China (English)

    N. SHIOMI; K. KANEKO; T. SETOGUCHI

    2005-01-01

    In order to clarify the natures of a rotating stall cell, the experimental investigation was carried out in a high specific-speed diagonal flow fan. The pressure field on the casing wall and the velocity fields at the rotor inlet and outlet were measured under rotating stall condition with a fast response pressure transducer and a single slant hot-wire probe, respectively. The data were processed using the "Double Phase-Locked Averaging (DPLA)"technique, which enabled to obtain the unsteady flow field with a rotating stall cell in the relative co-ordinate system fixed to the rotor. As a result, the structure and behavior of the rotating stall cell in a high specific-speed diagonal flow fan were shown.

  5. Speed enforcement in Norway

    DEFF Research Database (Denmark)

    Elvik, Rune

    2015-01-01

    This paper probes the relationship between changes in the risk of apprehension for speeding in Norway and changes in the amount of speeding. The paper is based on a game-theoretic model of how the rate of violations and the amount of enforcement is determined by the interaction between drivers...

  6. Speed and income

    DEFF Research Database (Denmark)

    Fosgerau, Mogens

    2005-01-01

    between speed and income is found again in the empirical analysis of a cross-sectional dataset comprising 60,000 observations of car trips. This is used to perform regressions of speed on income, distance travelled, and a number of controls. The results are clearly statistically significant and indicate...

  7. More Than Just Speed

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The 1,318-km Beijing-Shanghai High-Speed Railway will finally come into operation at the end of June.Since construction began three years ago,the speedy railway has grabbed worldwide attention because of its design as the world’s longest and fastesthigh-speed rail line utilizing the most advanced technology.

  8. Ultrahigh-Speed Optical Transmission Technology

    CERN Document Server

    Weber, Hans-Georg

    2007-01-01

    Ultrahigh-speed optical transmission technology is a key technology for increasing the communication capacity. In optical fibre networks, the number of wavelength channels and the bit rate per wavelength channel, i.e. the TDM (Time Division Multiplexing) bit rate, determine the transmission capacity. Currently, TDM bit rates of more than 40 Gbit/s require optical signal processing (Optical Time Division Multiplexing, OTDM). OTDM bit rates of up to 1.2 Tbit/s have already been reported. The devices developed for ultrahigh-speed optical transmission are not limited to communication applications only. They are key devices for high-speed optical signal processing, i.e. monitoring, measurement and control, and will thus give a wide technological basis for innovative science and technology. All these aspects of ultrahigh-speed optical transmission technology are described in detail in this book.

  9. Effectiveness of Motorcycle speed controlled by speed hump

    Directory of Open Access Journals (Sweden)

    Pornsiri Urapa

    2014-09-01

    Full Text Available Speed humps are one of the traffic calming measures widely accepted to control vehicle speed in the local road. Humps standards from the western countries are designed mainly for the passenger car. This study, therefore, aims to reveal the effectiveness of speed hump to control the motorcycle speed. This study observes the free-flow speed of the riders at the total of 20 speed bumps and humps. They are 0.3-14.8 meter in width and 5-18 centimeter in height. The results reveal that the 85th percentile speeds reduce 15-65 percent when crossing the speed bumps and speed humps. Besides, this study develops the speed model to predict the motorcycle mean speed and 85th percentile speed. It is found that speed humps follow the ITE standard can control motorcycle crossing speeds to be 25-30 Kph which are suitable to travel on the local road.

  10. ANALYSIS OF DEPOSIT MAINTENANCE IN ROTATING DRUMS

    Directory of Open Access Journals (Sweden)

    Krystian Malek

    2015-10-01

    Full Text Available Rotating drums are used to grinding, drying, mixing, screening, granulating and other processes in environmental engineering. Depending on the nature of the process they can be equipped with additional devices to support the processes. In this work, the effect of drum surface roughness on the behaviour of the feed during drumming. For this purpose, three types of bottom coverings with grain size of 40, 80 and 120 were used. In the experiment the methodology of sequential image analysis using PIV software was applied. The results of theoretical calculations and experimental works have shown significant discrepancies (of approx. 46% of speed characteristics for the minimum speed of the drum and smaller (amounting to approx. 5% for the critical speed. In case of change in the particle size of the drum coverings, there were no significant differences in the behaviour of the feed.

  11. Niobium carbide synthesis by solid-gas reaction using a rotating cylinder reactor

    Directory of Open Access Journals (Sweden)

    Fontes F. A. O.

    2004-01-01

    Full Text Available A rotating cylinder reactor was designed for the synthesis of niobium carbide powders at 1173 K. Niobium carbide, NbC, was prepared by carbothermal reduction starting from commercial niobium pentoxide powders. The reactor was heated using a custom-made, two-part, hinged, electric furnace with programmable temperature control. The design and operational details of the reactor are presented. The longitudinal temperature gradient inside the reactor was determined. Total reaction time was monitored by a gas chromatograph equipped with an FID detector for determination of methane concentrations. The results show that time of reaction depended on rotation speed. NbC was also prepared in a static-bed alumina reactor using the same conditions as in the previous case. The niobium carbide powders were characterized by X-ray diffraction and compared with commercially available products. Morphological, particle size distribution and surface area analyses were obtained using SEM, LDPS and BET, respectively. Therefore, the present study offers a significant technological contribution to the synthesis of NbC powders in a rotating cylinder reactor.

  12. Niobium carbide synthesis by solid-gas reaction using a rotating cylinder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Fontes, F.A.O.; Gomes, K.K.P.; Oliveira, S.A.; Souza, C.P.; Sousa, J.F. [Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Engenharia Quimica; Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Engenharia Mecanica, Rio Grande do f Natal, RN (Brazil). Programa de Pos-graduacao de Engenharia Quimica]. E-mail: franciscofontes@uol.com.br

    2004-09-01

    A rotating cylinder reactor was designed for the synthesis of niobium carbide powders at 1173 K. Niobium carbide, NbC, was prepared by carbothermal reduction starting from commercial niobium pentoxide powders. The reactor was heated using a custom-made, two-part, hinged, electric furnace with programmable temperature control. The design and operational details of the reactor are presented. The longitudinal temperature gradient inside the reactor was determined. Total reaction time was monitored by a gas chromatograph equipped with an FID detector for determination of methane concentrations. The results show that time of reaction depended on rotation speed. NbC was also prepared in a static-bed alumina reactor using the same conditions as in the previous case. The niobium carbide powders were characterized by X-ray diffraction and compared with commercially available products. Morphological, particle size distribution and surface area analyses were obtained using SEM, LDPS and BET, respectively. Therefore, the present study offers a significant technological contribution to the synthesis of NbC powders in a rotating cylinder reactor. (author)

  13. Differential rotation of geomagnetic field

    Institute of Scientific and Technical Information of China (English)

    WEI Zigang; XU Wenyao

    2003-01-01

    The latitudinal dependence of the westward drift in the main geomagnetic field is examined by using the correlation analysis of moving random pattern. The study reveals the characteristics in the differential rotation of the main field. The results show that the global geomagnetic field drifts westward with an average speed of 0.18°/a during 1900-2000. The westward drift rate is not symmetrical with respect to the equator. The maximum westward drift rate, 0.31°/a, occurs at the latitude --= -15°, forming a Rapid Westward Drift Belt (RDB) around this latitude. Going northward and southward from this belt, the drift rate decreases and reaches the minimum (0.12°/a) at --= 50° and the minimum (0.14°/a) at --= -56°, forming a Northern Hemisphere Slow Westward Drift Belt (N-SDB) and a Southern Hemisphere Slow Westward Drift Belt (S-SDB). Three phases can be detected in the evolution of the westward drift. In the first phase (1900-1940), the RDB dominates the global drift pattern. The westward drifts in this belt are much faster than those in other areas. In the second phase (1940-1960), the drift rates in the RDB are less than those in the first phase, while the drifts in the N-SDB and S-SDB are relatively large. In this phase, the differential rotation becomes less obvious. In the third phase (1960-2000), the westward drift in the RDB increases again and the differential rotation gradually becomes apparent.

  14. Short-rotation plantations

    Science.gov (United States)

    Philip E. Pope; Jeffery O. Dawson

    1989-01-01

    Short-rotation plantations offer several advantages over longer, more traditional rotations. They enhance the natural productivity of better sites and of tree species with rapid juvenile growth. Returns on investment are realized in a shorter period and the risk of loss is reduced compared with long term investments. Production of wood and fiber can be maximized by...

  15. Faraday rotation measure synthesis

    NARCIS (Netherlands)

    Brentjens, MA; de Bruyn, AG

    2005-01-01

    We extend the rotation measure work of Burn ( 1966, MNRAS, 133, 67) to the cases of limited sampling of lambda(2) space and non-constant emission spectra. We introduce the rotation measure transfer function (RMTF), which is an excellent predictor of n pi ambiguity problems with the lambda(2) coverag

  16. SMAP Faraday Rotation

    Science.gov (United States)

    Le Vine, David

    2016-01-01

    Faraday rotation is a change in the polarization as signal propagates through the ionosphere. At L-band it is necessary to correct for this change and measurements are made on the spacecraft of the rotation angle. These figures show that there is good agreement between the SMAP measurements (blue) and predictions based on models (red).

  17. A Rotating Quantum Vacuum

    CERN Document Server

    De Lorenci, V A

    1996-01-01

    We investigate which mapping we have to use to compare measurements made in a rotating frame to those made in an inertial frame. Using a "Lorentz-like" coordinate transformation we obtain that creation-anihilation operators of a massless scalar field in the rotating frame are not the same as those of an inertial observer. This leads to a new vacuum state (a rotating vacuum) which is a superposition of positive and negative frequency Minkowski particles. After this, introducing an apparatus device coupled linearly with the field we obtain that there is a strong correlation between number of rotating particles (in a given state) obtained via canonical quantization and via response function of the rotating detector. Finally, we analyse polarization effects in circular accelerators in the proper frame of the electron making a connection with the inertial frame point of view.

  18. Uniformly rotating neutron stars

    CERN Document Server

    Boshkayev, Kuantay

    2016-01-01

    In this chapter we review the recent results on the equilibrium configurations of static and uniformly rotating neutron stars within the Hartle formalism. We start from the Einstein-Maxwell-Thomas-Fermi equations formulated and extended by Belvedere et al. (2012, 2014). We demonstrate how to conduct numerical integration of these equations for different central densities ${\\it \\rho}_c$ and angular velocities $\\Omega$ and compute the static $M^{stat}$ and rotating $M^{rot}$ masses, polar $R_p$ and equatorial $R_{\\rm eq}$ radii, eccentricity $\\epsilon$, moment of inertia $I$, angular momentum $J$, as well as the quadrupole moment $Q$ of the rotating configurations. In order to fulfill the stability criteria of rotating neutron stars we take into considerations the Keplerian mass-shedding limit and the axisymmetric secular instability. Furthermore, we construct the novel mass-radius relations, calculate the maximum mass and minimum rotation periods (maximum frequencies) of neutron stars. Eventually, we compare a...

  19. Investigation on the propagation process of rotating detonation wave

    Science.gov (United States)

    Deng, Li; Ma, Hu; Xu, Can; Zhou, Changsheng; Liu, Xiao

    2017-10-01

    Effects of mass flow rate and equivalence ratio on the wave speed performance and instantaneous pressure characteristics of rotating detonation wave are investigated using hydrogen and air mixtures. The interaction between air and fuel manifolds and combustion chamber is also identified. The results show that the rotating detonation waves are able to adapt themselves to the changes of equivalence ratio during the run, the rotating detonation waves decayed gradually and then quenched after the shutdown of reactants supply. The wave speed performance is closely related to the mass flow rate and the pressure ratio of the fuel to air manifolds at different equivalence ratios. The blockage ratio of the air manifold increases with the increasing of the wave speed due to high-pressure detonation products, while increasing of the equivalence ratios will reduce the blockage ratio of the hydrogen manifold. Higher equivalence ratio can enhance the stabilization of the rotating detonation wave and lower equivalence ratio will lead to the large fluctuations of the lap time and instantaneous pressure magnitude. The overpressure of rotating detonation wave is determined by the combination of mass flow rate and equivalence ratio, which increases with the increasing of mass flow rate in the equivalence ratio ranges that the rotating detonation wave propagates stably. The secondary spike in the instantaneous pressure and ionization signals indicates that a shocked mixing zone exists near the fuel injection holes and the reflection of shock in the mixing zone induces the reaction.

  20. Influence of rotating wakes on separation in turbine exhaust diffusers

    Institute of Scientific and Technical Information of China (English)

    Olaf Sieker; Joerg R. Seume

    2008-01-01

    Highly efficient turbine exhaust diffuser cannot be designed without taking into account the unsteady interactions with the last rotating row of the turbine. Former investigations described in the literature show a very high potential compared to that of other parts of turbomachines for improving the diffuser. A scale model of a typical gas turbine exhaust diffuser is investigated experimentally. To investigate the influence of rotating wakes, measuremerits without a spoke wheel as well as measurements with a variable-speed rotating cylindrical spoke wheel with 2 mm- or 10 mm-spekes simulating turbine rotor wakes were made. Miniaturized 3-hole pneumatic probes as well as a 2D-Laser-Doppler-Velocimeter (LDV) were used to investigate velocity profiles. 122 static pressure tapings were used to measure several axial and circumferential static pressure distributions. Without a spoke-wheel the annular diffuser separates at the shroud for all swirl configurations. For the measurements with the 2 mm spoke wheel, the separating diffuser was unstable while keeping the test rig operating parameters constant. For a non-rotating 10mm spoke wheel and at rotational speeds less than 1,000 rpm, the annular diffuser separated at the shroud. Increasing the rotational speed of the 10mm spoke wheel, flow did not separate at the shroud and much higher pressure recovery than without spoke wheel has achieved.

  1. Propulsion health monitoring of a turbine engine disk using spin test data

    Science.gov (United States)

    Abdul-Aziz, Ali; Woike, Mark; Oza, Nikunj; Matthews, Bryan; Baakilini, George

    2010-03-01

    On line detection techniques to monitor the health of rotating engine components are becoming increasingly attractive options to aircraft engine companies in order to increase safety of operation and lower maintenance costs. Health monitoring remains a challenging feature to easily implement, especially, in the presence of scattered loading conditions, crack size, component geometry and materials properties. The current trend, however, is to utilize noninvasive types of health monitoring or nondestructive techniques to detect hidden flaws and mini cracks before any catastrophic event occurs. These techniques go further to evaluate materials' discontinuities and other anomalies that have grown to the level of critical defects which can lead to failure. Generally, health monitoring is highly dependent on sensor systems that are capable of performing in various engine environmental conditions and able to transmit a signal upon a predetermined crack length, while acting in a neutral form upon the overall performance of the engine system. Efforts are under way at NASA Glenn Research Center through support of the Intelligent Vehicle Health Management Project (IVHM) to develop and implement such sensor technology for a wide variety of applications. These efforts are focused on developing high temperature, wireless, low cost and durable products. Therefore, in an effort to address the technical issues concerning health monitoring of a rotor disk, this paper considers data collected from an experimental study using high frequency capacitive sensor technology to capture blade tip clearance and tip timing measurements in a rotating engine-like-disk-to predict the disk faults and assess its structural integrity. The experimental results collected at a range of rotational speeds from tests conducted at the NASA Glenn Research Center's Rotordynamics Laboratory will be evaluated using multiple data-driven anomaly detection techniques to identify anomalies in the disk. This study

  2. Design of a real-time spectroscopic rotating compensator ellipsometer without systematic errors

    Energy Technology Data Exchange (ETDEWEB)

    Broch, Laurent, E-mail: laurent.broch@univ-lorraine.fr [Laboratoire de Chimie Physique-Approche Multi-echelle des Milieux Complexes (LCP-A2MC, EA 4632), Universite de Lorraine, 1 boulevard Arago CP 87811, F-57078 Metz Cedex 3 (France); Stein, Nicolas [Institut Jean Lamour, Universite de Lorraine, UMR 7198 CNRS, 1 boulevard Arago CP 87811, F-57078 Metz Cedex 3 (France); Zimmer, Alexandre [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary BP 47870, F-21078 Dijon Cedex (France); Battie, Yann; Naciri, Aotmane En [Laboratoire de Chimie Physique-Approche Multi-echelle des Milieux Complexes (LCP-A2MC, EA 4632), Universite de Lorraine, 1 boulevard Arago CP 87811, F-57078 Metz Cedex 3 (France)

    2014-11-28

    We describe a spectroscopic ellipsometer in the visible domain (400–800 nm) based on a rotating compensator technology using two detectors. The classical analyzer is replaced by a fixed Rochon birefringent beamsplitter which splits the incidence light wave into two perpendicularly polarized waves, one oriented at + 45° and the other one at − 45° according to the plane of incidence. Both emergent optical signals are analyzed by two identical CCD detectors which are synchronized by an optical encoder fixed on the shaft of the step-by-step motor of the compensator. The final spectrum is the result of the two averaged Ψ and Δ spectra acquired by both detectors. We show that Ψ and Δ spectra are acquired without systematic errors on a spectral range fixed from 400 to 800 nm. The acquisition time can be adjusted down to 25 ms. The setup was validated by monitoring the first steps of bismuth telluride film electrocrystallization. The results exhibit that induced experimental growth parameters, such as film thickness and volumic fraction of deposited material can be extracted with a better trueness. - Highlights: • High-speed rotating compensator ellipsometer equipped with 2 detectors. • Ellipsometric angles without systematic errors • In-situ monitoring of electrocrystallization of bismuth telluride thin layer • High-accuracy of fitted physical parameters.

  3. Risk matrix model for rotating equipment

    Directory of Open Access Journals (Sweden)

    Wassan Rano Khan

    2014-07-01

    Full Text Available Different industries have various residual risk levels for their rotating equipment. Accordingly the occurrence rate of the failures and associated failure consequences categories are different. Thus, a generalized risk matrix model is developed in this study which can fit various available risk matrix standards. This generalized risk matrix will be helpful to develop new risk matrix, to fit the required risk assessment scenario for rotating equipment. Power generation system was taken as case study. It was observed that eight subsystems were under risk. Only vibration monitor system was under high risk category, while remaining seven subsystems were under serious and medium risk categories.

  4. Traffic speed management

    Directory of Open Access Journals (Sweden)

    Subotić Jovana Lj.

    2014-01-01

    Full Text Available Speed, and vehicles themselves, affect the level of service and road safety, quality of life, noise from traffic, the environment, health, air pollution, emission of carbon dioxide, global warming, the economy and consumption of non-renewable energy such as oil. Therefore, the speed management of the traffic of multiple significance and that should be primarily to provide effective and economical conditions of the modern and preventive protection of human life as the greatest treasure and then the material resources. The way to accomplish this is by using various (different measures such as: appropriate planning and projecting roads and streets, speed control, the legislation, enforcement, campaigns, education, advanced technologies (ITS.

  5. Stability and Speed Control of a Series-Wound DC Motor

    Science.gov (United States)

    Khoroshun, A. S.

    2016-07-01

    A speed control for a series-wound DC motor is proposed. It is shown that steady-state rotation is stabile and robust. Stability is analyzed using a quadratic Lyapunov function. Its explicit expression is derived

  6. Interaction of ionic liquid with water with variation of water content in 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6])/TX-100/water ternary microemulsions monitored by solvent and rotational relaxation of coumarin 153 and coumarin 490.

    Science.gov (United States)

    Seth, Debabrata; Chakraborty, Anjan; Setua, Palash; Sarkar, Nilmoni

    2007-06-14

    The interaction of water with room temperature ionic liquid (RTIL) [bmim][PF6] has been studied in [bmim][PF6]/TX-100/water ternary microemulsions by solvent and rotational relaxation of coumarin 153 (C-153) and coumarin 490 (C-490). The rotational relaxation and average solvation time of C-153 and C-490 gradually decrease with increase in water content of the microemulsions. The gradual increase in the size of the microemulsion with increase in w0 (w0=[water]/[surfactant]) is evident from dynamic light scattering measurements. Consequently the mobility of the water molecules also increases. In comparison to pure water the retardation of solvation time in the RTIL containing ternary microemulsions is very less. The authors have also reported the solvation time of C-490 in neat [bmim][PF6]. The solvation time of C-490 in neat [bmim][PF6] is bimodal with time constants of 400 ps and 1.10 ns.

  7. Jet Engine Bird Ingestion Simulations: Comparison of Rotating to Non-Rotating Fan Blades

    Science.gov (United States)

    Howard, Samuel A.; Hammer, Jeremiah T.; Carney, Kelly S.; Pereira, J. Michael

    2013-01-01

    Bird strike events in commercial airliners are a fairly common occurrence. According to data collected by the US Department of Agriculture, over 80,000 bird strikes were reported in the period 1990 to 2007 in the US alone (Ref. 1). As a result, bird ingestion is an important factor in aero engine design and FAA certification. When it comes to bird impacts on engine fan blades, the FAA requires full-scale bird ingestion tests on an engine running at full speed to pass certification requirements. These rotating tests are complex and very expensive. To reduce development costs associated with new materials for fan blades, it is desirable to develop more cost effective testing procedures than full-scale rotating engine tests for material evaluation. An impact test on a nonrotating single blade that captures most of the salient physics of the rotating test would go a long way towards enabling large numbers of evaluative material screening tests. NASA Glenn Research Center has been working to identify a static blade test procedure that would be effective at reproducing similar results as seen in rotating tests. The current effort compares analytical simulations of a bird strike on various non-rotating blades to a bird strike simulation on a rotating blade as a baseline case. Several different concepts for simulating the rotating loads on a non-rotating blade were analyzed with little success in duplicating the deformation results seen in the rotating case. The rotating blade behaves as if it were stiffer than the non-rotating blade resulting in less plastic deformation from a given bird impact. The key factor limiting the success of the non-rotating blade simulations is thought to be the effect of gyroscopics. Prior to this effort, it was anticipated the difficulty would be in matching the prestress in the blade due to centrifugal forces Additional work is needed to verify this assertion, and to determine if a static test procedure can simulate the gyroscopic effects in

  8. Wind_Speeds_Master

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set included wind speeds for each subregion in the study (Georges Bank, Gulf of Maine, Southern New England, Middle Atlantic Bight) . The data came from...

  9. Speeding up Transportation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ 2007 was an excellent year for the transportation industry, marked by high speed railway transportation, development of the national expressway network and launch of the Chang'e lunar probe satellite.

  10. Chaotic rotation of Hyperion?

    Science.gov (United States)

    Binzel, R. P.; Green, J. R.; Opal, C. B.

    1986-01-01

    Thomas et al. (1984) analyzed 14 Voyager 2 images of Saturn's satellite Hyperion and interpreted them to be consistent with a coherent (nonchaotic) rotation period of 13.1 days. This interpretation was criticized by Peale and Wisdom (1984), who argued that the low sampling frequency of Voyager data does not allow chaotic or nonchaotic rotation to be distinguished. New observations obtained with a higher sampling frequency are reported here which conclusively show that the 13.1 day period found by Thomas et al. was not due to coherent rotation.

  11. A rotating quantum vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Lorenci, V.A. de; Svaiter, N.F. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1996-11-01

    It was investigated which mapping has to be used to compare measurements made in a rotating frame to those made in an inertial frame. Using a non-Galilean coordinate transformation, the creation-annihilation operators of a massive scalar field in the rotating frame are not the same as those of an inertial observer. This leads to a new vacuum state(a rotating vacuum) which is a superposition of positive and negative frequency Minkowski particles. Polarization effects in circular accelerators in the proper frame of the electron making a connection with the inertial frame point of view were analysed. 65 refs.

  12. High speed heterostructure devices

    CERN Document Server

    Beer, Albert C; Willardson, R K; Kiehl, Richard A; Sollner, T C L Gerhard

    1994-01-01

    Volume 41 includes an in-depth review of the most important, high-speed switches made with heterojunction technology. This volume is aimed at the graduate student or working researcher who needs a broad overview andan introduction to current literature. Key Features * The first complete review of InP-based HFETs and complementary HFETs, which promise very low power and high speed * Offers a complete, three-chapter review of resonant tunneling * Provides an emphasis on circuits as well as devices.

  13. Police enforcement and driving speed.

    NARCIS (Netherlands)

    2008-01-01

    Speed limits are violated frequently in the Netherlands. As speed is an important factor in road crashes, the surveillance of driving speeds is one of the spearheads in the policy plans of the Dutch police. Different methods of speed enforcement have proved to be effective in reducing speed and cras

  14. A method to deconvolve stellar rotational velocities II

    CERN Document Server

    Christen, A; Cure, M; Rial, D F; Cassetti, J

    2016-01-01

    Knowing the distribution of stellar rotational velocities is essential for the understanding stellar evolution. Because we measure the projected rotational speed vsini, we need to solve an ill-posed problem given by a Fredholm integral of the first kind to recover the true rotational velocity distribution. After discretization of the Fredholm integral, we apply the Tikhonov regularization method to obtain directly the probability distribution function for stellar rotational velocities. We propose a simple and straightforward procedure to determine the Tikhonov parameter. We applied Monte Carlo simulations to prove that Tikhonov method is a consistent estimator and asymptotically unbiased. This method is applied to a sample of cluster stars. We obtain confidences intervals using bootstrap method. Our results are in good agreement with the one obtained using the Lucy method, in recovering the probability density distribution of rotational velocities. Furthermore, Lucy estimation lies inside our confidence inter...

  15. Rotation-Dependent Catastrophic Disruption of Gravitational Aggregates

    CERN Document Server

    Ballouz, Ronald-Louis; Michel, Patrick; Schwartz, Stephen R

    2014-01-01

    We carry out a systematic exploration of the effect of pre-impact rotation on the outcomes of low-speed collisions between planetesimals modeled as gravitational aggregates. We use pkdgrav, a cosmology code adapted to collisional problems and recently enhanced with a new soft-sphere collision algorithm that includes more realistic contact forces. A rotating body has lower effective surface gravity than a non-rotating one and therefore might suffer more mass loss as the result of a collision. What is less well understood, however, is whether rotation systematically increases mass loss on average regardless of the impact trajectory. This has important implications for the efficiency of planet formation via planetesimal growth, and also more generally for the determination of the impact energy threshold for catastrophic disruption (leading to the largest remnant retaining 50% of the original mass), as this has generally only been evaluated for non-spinning bodies. We find that for most collision scenarios, rotat...

  16. Modeling of high speed micro rotors in moderate flow confinement

    NARCIS (Netherlands)

    Dikmen, E.; Hoogt, van der P.J.M.; Aarts, R.G.K.M.

    2008-01-01

    The recent developments in high speed micro rotating machinery lead to the need for multiphysical modeling of the rotor and the surrounding medium. In this study, thermal and flow induced effects on rotor dynamics of geometries with moderate flow confinement are studied. The structure is modeled via

  17. Calculating Speed of Sound

    Science.gov (United States)

    Bhatnagar, Shalabh

    2017-01-01

    Sound is an emerging source of renewable energy but it has some limitations. The main limitation is, the amount of energy that can be extracted from sound is very less and that is because of the velocity of the sound. The velocity of sound changes as per medium. If we could increase the velocity of the sound in a medium we would be probably able to extract more amount of energy from sound and will be able to transfer it at a higher rate. To increase the velocity of sound we should know the speed of sound. If we go by the theory of classic mechanics speed is the distance travelled by a particle divided by time whereas velocity is the displacement of particle divided by time. The speed of sound in dry air at 20 °C (68 °F) is considered to be 343.2 meters per second and it won't be wrong in saying that 342.2 meters is the velocity of sound not the speed as it's the displacement of the sound not the total distance sound wave covered. Sound travels in the form of mechanical wave, so while calculating the speed of sound the whole path of wave should be considered not just the distance traveled by sound. In this paper I would like to focus on calculating the actual speed of sound wave which can help us to extract more energy and make sound travel with faster velocity.

  18. RoboPol: optical polarization-plane rotations and flaring activity in blazars

    CERN Document Server

    Blinov, D; Papadakis, I E; Hovatta, T; Pearson, T J; Liodakis, I; Panopoulou, G V; Angelakis, E; Baloković, M; Das, H; Khodade, P; Kiehlmann, S; King, O G; Kus, A; Kylafis, N; Mahabal, A; Marecki, A; Modi, D; Myserlis, I; Paleologou, E; Papamastorakis, I; Pazderska, B; Pazderski, E; Rajarshi, C; Ramaprakash, A; Readhead, A C S; Reig, P; Tassis, K; Zensus, J A

    2016-01-01

    We present measurements of rotations of the optical polarization of blazars during the second year of operation of RoboPol, a monitoring programme of an unbiased sample of gamma-ray bright blazars specially designed for effective detection of such events, and we analyse the large set of rotation events discovered in two years of observation. We investigate patterns of variability in the polarization parameters and total flux density during the rotation events and compare them to the behaviour in a non-rotating state. We have searched for possible correlations between average parameters of the polarization-plane rotations and average parameters of polarization, with the following results: (1) there is no statistical association of the rotations with contemporaneous optical flares; (2) the average fractional polarization during the rotations tends to be lower than that in a non-rotating state; (3) the average fractional polarization during rotations is correlated with the rotation rate of the polarization plane...

  19. Naturalistic speeding data: Drivers aged 75 years and older

    Directory of Open Access Journals (Sweden)

    Anna Chevalier

    2016-09-01

    Full Text Available The data presented in this article are related to the research article entitled “A longitudinal investigation of the predictors of older drivers׳ speeding behavior” (Chevalier et al., 2016 [1], wherein these speed events were used to investigate older drivers speeding behavior and the influence of cognition, vision, functional decline, and self-reported citations and crashes on speeding behavior over a year of driving. Naturalistic speeding behavior data were collected for up to 52 weeks from volunteer drivers aged 75–94 years (median 80 years, 52% male living in the suburban outskirts of Sydney. Driving data were collected using an in-vehicle monitoring device. Global Positioning System (GPS data were recorded at each second and determined driving speed through triangulation of satellite collected location data. Driving speed data were linked with mapped speed zone data based on a service-provider database. To measure speeding behavior, speed events were defined as driving 1 km/h or more, with a 3% tolerance, above a single speed limit, averaged over 30 s. The data contains a row per 124,374 speed events. This article contains information about data processing and quality control.

  20. Naturalistic speeding data: Drivers aged 75 years and older.

    Science.gov (United States)

    Chevalier, Anna; Chevalier, Aran John; Clarke, Elizabeth; Wall, John; Coxon, Kristy; Brown, Julie; Ivers, Rebecca; Keay, Lisa

    2016-09-01

    The data presented in this article are related to the research article entitled "A longitudinal investigation of the predictors of older drivers׳ speeding behavior" (Chevalier et al., 2016) [1], wherein these speed events were used to investigate older drivers speeding behavior and the influence of cognition, vision, functional decline, and self-reported citations and crashes on speeding behavior over a year of driving. Naturalistic speeding behavior data were collected for up to 52 weeks from volunteer drivers aged 75-94 years (median 80 years, 52% male) living in the suburban outskirts of Sydney. Driving data were collected using an in-vehicle monitoring device. Global Positioning System (GPS) data were recorded at each second and determined driving speed through triangulation of satellite collected location data. Driving speed data were linked with mapped speed zone data based on a service-provider database. To measure speeding behavior, speed events were defined as driving 1 km/h or more, with a 3% tolerance, above a single speed limit, averaged over 30 s. The data contains a row per 124,374 speed events. This article contains information about data processing and quality control.

  1. Rotator Cuff Injuries

    Science.gov (United States)

    ... cuff are common. They include tendinitis, bursitis, and injuries such as tears. Rotator cuff tendons can become ... cuff depends on age, health, how severe the injury is, and how long you've had the ...

  2. Fractal Aggregation Under Rotation

    Institute of Scientific and Technical Information of China (English)

    WU Feng-Min; WU Li-Li; LU Hang-Jun; LI Qiao-Wen; YE Gao-Xiang

    2004-01-01

    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω the fractal dimension decreases with increasing ω, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  3. Fractal Aggregation Under Rotation

    Institute of Scientific and Technical Information of China (English)

    WUFeng-Min; WULi-Li; LUHang-Jun; LIQiao-Wen; YEGao-Xiang

    2004-01-01

    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω; thefractal dimension decreases with increasing ω;, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  4. Solar rotation gravitational moments

    Directory of Open Access Journals (Sweden)

    A. Ajabshirizadeh

    2005-09-01

    Full Text Available   Gravitational multipole moments of the Sun are still poorly known. Theoretically, the difficulty is mainly due to the differential rotation for which the velocity rate varies both on the surface and with the depth. From an observational point of view, the multipole moments cannot be directly measured. However, recent progresses have been made proving the existence of a strong radial differential rotation in a thin layer near the solar surface (the leptocline. Applying the theory of rotating stars, we will first compute values of J2 and J4 taking into account the radial gradient of rotation, then we will compare these values with the existing ones, giving a more complete review. We will explain some astrophysical outcomes, mainly on the relativistic Post Newtonian parameters. Finally we will conclude by indicating how space experiments (balloon SDS flights, Golf NG, Beppi-Colombo, Gaia... will be essential to unambiguously determine these parameters.

  5. A parametric study on the growth of yield front in rotating annular disks

    African Journals Online (AJOL)

    user

    The growth of elastic-plastic front under post-elastic conditions in high speed rotating ... In a recent work Alexandrova and Villa Real (2007) reported the influences of ... approximate the radial displacement field are generated numerically ...

  6. Experimental Studies of Flow Patterns of Different Fluids in a Partially Filled Rotating Cylinder

    Directory of Open Access Journals (Sweden)

    P.R. Mukunda

    2009-01-01

    Full Text Available An attempt has been made to investigate the various parameters affecting the fluid behaviour, partially filled in a rotating cylinder. When the cylinder is rotating at ‘high’ speed, a liquid forms a hollow cylinder. Different patterns are observed in the fluids for the rotatioal speeds below a critical speed. This study should give us some insight into molten metal behaviour during centrifugal casting. An extensive experimental investigation is required to obtain an appropriate functional relationship by knowing and understanding some dimensionless parameters. Here the effect of dimensionless parameters ε (which is 2 g/ω2d, where g, ω and d denotes gravitational acceleration, container rotation rate and inner diameter of liquid cylinder and G (number of times the gravity was studied as variation of rotation speed, viscosity and aspect ratio of the mould.

  7. NUMERICAL SIMULATIONS FOR THE CASE OF RIGID ROTATING KINEMATIC COUPLING WITH BIG CLEARANCE

    Directory of Open Access Journals (Sweden)

    Jan-Cristian GRIGORE

    2010-10-01

    Full Text Available In this paper an algorithm based on [1] [2] are numerical simulations, achieving generalized coordinates of motion, positions, speeds of a rigid rotating kinematic coupling with big clearance in joint, case without friction

  8. High Speed Gear Sized and Configured to Reduce Windage Loss

    Science.gov (United States)

    Kunz, Robert F. (Inventor); Medvitz, Richard B. (Inventor); Hill, Matthew John (Inventor)

    2013-01-01

    A gear and drive system utilizing the gear include teeth. Each of the teeth has a first side and a second side opposite the first side that extends from a body of the gear. For each tooth of the gear, a first extended portion is attached to the first side of the tooth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates. The gear may be utilized in drive systems that may have high rotational speeds, such as speeds where the tip velocities are greater than or equal to about 68 m/s. Some embodiments of the gear may also utilize teeth that also have second extended portions attached to the second sides of the teeth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates.

  9. Spontaneous sidebanding in high speed rotordynamics

    Science.gov (United States)

    Ehrich, F. F.

    1992-10-01

    It is noted that the spontaneous sideband spacing frequency seems to be a whole number fraction (1/J) of the operating speed which indicates that the wave form is periodic and completes a full cycle every J rotations of the rotor. Employing a numerical model of a rotor that simulates local contact with a stator in close proximity as a bilinear spring, studies have been conducted to explore the circumstances for this spontaneous sidebanding. Two general classes of this type of response are determined in a system that is effectively single-degree-of-freedom.

  10. Electromagnetic rotational actuation.

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Alexander Lee

    2010-08-01

    There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

  11. Rotational spectrum of phenylglycinol

    Science.gov (United States)

    Simão, Alcides; Peña, Isabel; Cabezas, Carlos; Alonso, José L.

    2014-11-01

    Solid samples of phenylglycinol were vaporized by laser ablation and investigated through rotational spectroscopy in a supersonic expansion using two different techniques: chirped pulse Fourier transform microwave spectroscopy and narrow band molecular beam Fourier transform microwave spectroscopy. One conformer, bearing an O-H···N and an N-H···π intramolecular hydrogen bonds, could be successfully identified by comparison of the experimental rotational and 14N nuclear quadruple coupling constants with those predicted theoretically.

  12. Earth rotation and geodynamics

    OpenAIRE

    Bogusz Janusz; Brzezinski Aleksander; Kosek Wieslaw; Nastula Jolanta

    2015-01-01

    This paper presents the summary of research activities carried out in Poland in 2011-2014 in the field of Earth rotation and geodynamics by several Polish research institutions. It contains a summary of works on Earth rotation, including evaluation and prediction of its parameters and analysis of the related excitation data as well as research on associated geodynamic phenomena such as geocentre motion, global sea level change and hydrological processes. The second part of the paper deals wit...

  13. Development of a Revolutionary High Speed Spindle

    Science.gov (United States)

    Agba, Emmanuel I.

    1999-01-01

    This report presents the development of a hydraulic motor driven spindle system to be employed for high speed machining of composite materials and metals. The spindle system is conceived to be easily retrofitted into conventional milling machines. The need for the hydraulic spindle arises because of the limitations placed on conventional electric motor driven spindles by the low cutting power and the presence of vibrational phenomena associated with voltage frequency at high rotational speeds. Also, the electric motors are usually large and expensive when power requirements are moderately high. In contrast, hydraulic motor driven spindles promise a distinct increase in spindle life over the conventional electric motor driven spindles. In this report, existing technologies applicable to spindle holder for severe operating conditions were reviewed, conceptual designs of spindle holder system were developed and evaluated, and a detailed design of an acceptable concept was conducted. Finally, a rapid prototype of the design was produced for design evaluation.

  14. Safety issues in high speed machining

    Science.gov (United States)

    1994-05-01

    There are several risks related to High-Speed Milling, but they have not been systematically determined or studied so far. Increased loads by high centrifugal forces may result in dramatic hazards. Flying tools or fragments from a tool with high kinetic energy may damage surrounding people, machines and devices. In the project, mechanical risks were evaluated, theoretic values for kinetic energies of rotating tools were calculated, possible damages of the flying objects were determined and terms to eliminate the risks were considered. The noise levels of the High-Speed Machining center owned by the Helsinki University of Technology (HUT) and the Technical Research Center of Finland (VTT) in practical machining situation were measured and the results were compared to those after basic preventive measures were taken.

  15. Construction and laboratory test of the fiber optic rotational seismograph FOSREM for rotational seismology area of interest

    Science.gov (United States)

    Kurzych, Anna; Jaroszewicz, Leszek R.; Kowalski, Jerzy K.

    2017-05-01

    A relatively young field of study named Rotational Seismology caused a highly interest in an investigation of rotational movements generated by earthquakes, explosions, and ambient vibrations. It includes a wide range of scientific branches. However, this field needs to apply appropriate rotational sensors which should fulfill restrict technical requirements. The presented in this work system FOSREM (Fibre-Optic System for Rotational Events and Phenomena Monitoring) seems to be a promising rotational sensor for such investigation. FOSREM works by measuring the Sagnac effect and generally consists of two basic elements: optical sensor and electronic part. Regarding to its theoretical sensitivity equals 2·10-8 rad/s/Hz1/2, it enables to measure rotation in a wide range of signal amplitude (10-8 rad/s ÷ 10 rad/s) and frequency (DC ÷ 328.12 Hz). Moreover, FOSREM is mobile and remotely controlled via Internet using a special designed software.

  16. Enstrophy-based proper orthogonal decomposition of flow past rotating cylinder at super-critical rotating rate

    Science.gov (United States)

    Sengupta, Tapan K.; Gullapalli, Atchyut

    2016-11-01

    Spinning cylinder rotating about its axis experiences a transverse force/lift, an account of this basic aerodynamic phenomenon is known as the Robins-Magnus effect in text books. Prandtl studied this flow by an inviscid irrotational model and postulated an upper limit of the lift experienced by the cylinder for a critical rotation rate. This non-dimensional rate is the ratio of oncoming free stream speed and the surface speed due to rotation. Prandtl predicted a maximum lift coefficient as CLmax = 4π for the critical rotation rate of two. In recent times, evidences show the violation of this upper limit, as in the experiments of Tokumaru and Dimotakis ["The lift of a cylinder executing rotary motions in a uniform flow," J. Fluid Mech. 255, 1-10 (1993)] and in the computed solution in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)]. In the latter reference, this was explained as the temporal instability affecting the flow at higher Reynolds number and rotation rates (>2). Here, we analyze the flow past a rotating cylinder at a super-critical rotation rate (=2.5) by the enstrophy-based proper orthogonal decomposition (POD) of direct simulation results. POD identifies the most energetic modes and helps flow field reconstruction by reduced number of modes. One of the motivations for the present study is to explain the shedding of puffs of vortices at low Reynolds number (Re = 60), for the high rotation rate, due to an instability originating in the vicinity of the cylinder, using the computed Navier-Stokes equation (NSE) from t = 0 to t = 300 following an impulsive start. This instability is also explained through the disturbance mechanical energy equation, which has been established earlier in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)].

  17. DYNAMIC ANALYSIS OF A SPATIAL COUPLED TIMOSHENKO ROTATING SHAFT WITH LARGE DISPLACEMENTS

    Institute of Scientific and Technical Information of China (English)

    朱怀亮

    2002-01-01

    The dynamic simulation is presented for an axial moving flexible rotating shafts,which have large rigid motions and small elastic deformation. The effects of the axial inertia,shear deformation, rotating inertia, gyroscopic moment, and dynamic unbalance areconsidered based on the Timoshenko rotating shaft theory. The equations of motion andboundary conditions are derived by Hamilton principle, and the solution is obtained by usingthe perturbation approach and cssuming mode method. This study confirms that the influenceof the axial rigid motion, shear deformation, slenderness ratio and rotating speed on thedynamic behavior of Timoshenko rotating shaft is evident, especially to a high-angularvelocity rotor.

  18. Trapping and rotating microparticles and bacteria with moiré-based optical propelling beams.

    Science.gov (United States)

    Zhang, Peng; Hernandez, Daniel; Cannan, Drake; Hu, Yi; Fardad, Shima; Huang, Simon; Chen, Joseph C; Christodoulides, Demetrios N; Chen, Zhigang

    2012-08-01

    We propose and demonstrate trapping and rotation of microparticles and biological samples with a moiré-based rotating optical tweezers. We show that polystyrene beads, as well as Escherichia coli cells, can be rotated with ease, while the speed and direction of rotation are fully controllable by a computer, obviating mechanical movement or phase-sensitive interference. Furthermore, we demonstrate experimentally the generation of white-light propelling beams and arrays, and discuss the possibility of optical tweezing and particle micro-manipulation based on incoherent white-light rotating patterns.

  19. The Design of Speed of Dropping Liquid Monitoring Device Based on Microcomputer System%基于单片机系统的液体点滴速度监控装置的设计

    Institute of Scientific and Technical Information of China (English)

    滕春阳; 孙长江; 随顺科

    2011-01-01

    This system design AT89S52 SCM is as the core,with the keyboard and infrared sensor system in 1602 as input,liquid crystal display and motor as the output of the system of intelligent control and testing system.Infusion The system consists of water droplets speed test system,water speed control system,display device and single-chip microcomputer system,wireless transmission system,the keyboard and the alarm system components,etc.%本系统设计是以AT89S52单片机为核心,以键盘及红外对射式传感器作为输入系统,以1602液晶显示屏及电动机作为输出系统的智能化输液控制及检测系统。该系统主要由水滴速度测试系统、水速控制系统、显示装置、单片机系统、无线传输系统、键盘和报警等系统组成。

  20. Heat Transfer Through A Rotating Ball Bearing At Low Angular Velocities

    OpenAIRE

    Isert, Sarah

    2011-01-01

    Bearings are commonly used in mechanical systems when there are rotating parts in the system. For bearings that run at speeds above about 1000 revolutions per minute, such as those used in aircraft turbines, machining tools, and automotive engines, it is important to take into account the heat transfer through the bearing system due to friction. Heat transfer is generally not considered for applications where the bearing is rotating at low speeds, such as clocks and bicycles. However, for cer...

  1. Variable Speed Rotor System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Variable speed rotors will give helicopters several advantages: higher top speed, greater fuel efficiency, momentary emergency over-power, resonance detuning...

  2. Miniature, Variable-Speed Control Moment Gyroscope

    Science.gov (United States)

    Bilski, Steve; Kline-Schoder, Robert; Sorensen, Paul

    2011-01-01

    The Miniature Variable-Speed Control Moment Gyroscope (MVS-CMG) was designed for small satellites (mass from less than 1 kg up to 500 kg). Currently available CMGs are too large and heavy, and available miniature CMGs do not provide sufficient control authority for use on practical satellites. This primarily results from the need to greatly increase the speed of rotation of the flywheel in order to reduce the flywheel size and mass. This goal was achieved by making use of a proprietary, space-qualified, high-speed (100,000 rpm) motor technology to spin the flywheel at a speed ten times faster than other known miniature CMGs under development. NASA is supporting innovations in propulsion, power, and guidance and navigation systems for low-cost small spacecraft. One of the key enabling technologies is attitude control mechanisms. CMGs are particularly attractive for spacecraft attitude control since they can achieve higher torques with lower mass and power than reaction wheels, and they provide continuous torque capability that enables precision pointing (in contrast to on-off thruster control). The aim of this work was to develop a miniature, variable-speed CMG that is sized for use on small satellites. To achieve improved agility, these spacecraft must be able to slew at high rate, which requires attitude control actuators that can apply torques on the order of 5 N-m. The MVS-CMG is specifically designed to achieve a high-torque output with a minimum flywheel and system mass. The flywheel can be run over a wide range of speeds, which is important to help reduce/eliminate potential gimbal lock, and can be used to optimize the operational envelope of the CMG.

  3. Rotating superconductor magnet for producing rotating lobed magnetic field lines

    Science.gov (United States)

    Hilal, Sadek K.; Sampson, William B.; Leonard, Edward F.

    1978-01-01

    This invention provides a rotating superconductor magnet for producing a rotating lobed magnetic field, comprising a cryostat; a superconducting magnet in the cryostat having a collar for producing a lobed magnetic field having oppositely directed adjacent field lines; rotatable support means for selectively rotating the superconductor magnet; and means for energizing the superconductor magnet.

  4. Motor Controlled Rotating Base for Directional Submarine Antennas

    Science.gov (United States)

    2012-09-28

    steel gear 172 that is attached to the rotating platform 150. [0044] Suitable motors include, but are not limited to, a brushless DC motor that...parts. Different motors and different gear heads may be used to provide different torques and operating speeds. A different model pin 26

  5. Structural looseness investigation in slow rotating permanent magnet generators

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Mijatovic, Nenad; Sweeney, Christian Walsted;

    2016-01-01

    Structural looseness in electric machines is a condition influencing the alignment of the machine and thus the overall bearing health. In this work, assessment of the above mentioned failure mode is tested on a slow rotating (running speed equal to 0.7Hz) permanent magnet generator (PMG), while...

  6. Film thickness in grease lubricated slow rotating rolling bearings

    NARCIS (Netherlands)

    Morales-Espejel, G.E.; Lugt, Pieter Martin; Pasaribu, H.R.; Cen, H.

    2014-01-01

    Film thickness measurements in grease lubricated contacts are presented for different greases. The conditions used in the experiments are similar to the ones expected in fully-flooded slow rotating bearings. The results show that at very low speeds grease produces film thicknesses substantially thic

  7. Optical vibration and deviation measurement of rotating machine parts

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer (LDV).

  8. Vibration characteristics analysis of rotating shrouded blades with impacts

    Science.gov (United States)

    Ma, Hui; Xie, Fangtao; Nai, Haiqiang; Wen, Bangchun

    2016-09-01

    A dynamic model of rotating shrouded blades with impacts among adjacent shrouded blades is established considering the effects of the centrifugal stiffening, spin softening and Coriolis force, and the model is validated using finite element method. In the proposed model, the shrouded blade is simplified as a cantilever Euler-Bernoulli beam with a mass point at the free end, and the flexural dynamic stiffness of shrouded blade is selected as contact stiffness during collision. Based on the developed model, the effects of symmetric and asymmetric shroud gaps, rotational speeds, and aerodynamic force amplitudes on the dynamic characteristics of shrouded blades are analyzed through Newmark-β numerical method. The results indicate that (1) the vibro-impact responses of shrouded blades under some asymmetric gaps are more complicated than that under symmetric gap. (2) With the increase of rotational speed from 6000 to 10,000 rev/min, the system vibration experiences from period-three motion, through chaotic motion, finally to period-one motion during collision process because the increasing rotational speed changes the flexural dynamic stiffness of rotating blade. (3) The vibration displacements of shrouded blades increase linearly, and impact force increases linearly with the increase of aerodynamic force amplitude.

  9. Compact sensor for measuring nonlinear rotational dynamics of driven magnetic microspheres with biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    McNaughton, Brandon H. [Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Applied Physics Program, University of Michigan, Ann Arbor, MI 48109-1040 (United States)], E-mail: bmcnaugh@umich.edu; Kinnunen, Paivo [Applied Physics Program, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Smith, Ron G.; Pei, S.N. [Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Torres-Isea, Ramon [Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Kopelman, Raoul [Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Applied Physics Program, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Clarke, Roy [Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Applied Physics Program, University of Michigan, Ann Arbor, MI 48109-1040 (United States)

    2009-05-15

    The nonlinear rotation response of a magnetic particle occurs when a driving magnetic field, used to rotate the magnetic particle, exceeds a critical frequency. This type of nonlinear rotational dynamic depends on several physical parameters, such as the rotational drag that the particle experiences. Shifts in this nonlinear rotational frequency offer a dynamic approach for the detection of bacteria, measurement of their growth, their response to chemical agents, and other biomedical applications. Therefore, we have developed a stand-alone prototype device that utilizes an elegant combination of a laser diode and photodiode to monitor particle rotation.

  10. PERSONALITY AND SPEEDING

    Directory of Open Access Journals (Sweden)

    Richard TAY

    2003-01-01

    Full Text Available While there has been extensive research on the effect of sensation seeking on risky driving, relatively little research has been conducted on Type-A personality. The motivations for speeding are likely to be different for each group and these differences have important implications for the design, implementation and expected efficacy of road safety countermeasures. This paper examines the influence of sensation seeking and Type-A behavior pattern on speeding behaviour. A sample of 139 staff and students in an Australian university were surveyed in July 2001 to gather information on their gender, age, personality and self-reported speeding behaviour. The data were analysed using correlations and analysis of variance procedures. Finally, some implications for road safety are discussed.

  11. Study on weld formation in a novel rotating arc horizontal GMAW

    Institute of Scientific and Technical Information of China (English)

    Guo Ning; Lin Sanbao; Fan Chenglei; Zhang Yaqi; Yang Chunli

    2009-01-01

    A novel rotating arc horizontal welding process was developed for solving the sagging of the molten pool which bottlenecks the application and the development of the horizontal welding. The principle of the effect of the rotating arc on the molten pool is that the rotating arc process not only can reduce the welding heat input by prolonging the welding path in the same welding distance caused by the arc rotation, but also disperse the arc force to affect the sidewall periodically to support the molten metal near the upper sidewall. The effects of the rotating speed and arc voltage on the weld formation were studied.The results indicate that there is an appropriate range of the rotating speed and the arc voltage to obtain the defect free horizontal welding.

  12. Experimental Testing of a Generic Submarine Model in the DSTO Low Speed Wind Tunnel. Phase 2

    Science.gov (United States)

    2014-03-01

    Defence Science and Technology Organisation Technical Report DSTO-TR-1622, 2004. [3] Barlow, J. B., Rae , W. H. and Pope, A., Low-Speed Wind Tunnel...kW (900 hp) electric motor driving a 3.96 m diameter eight bladed fan, with a maximum rotational speed 750 RPM, manually controlled. Cooling 40 °C

  13. Demanda energética de uma semeadora-adubadora em diferentes velocidades de deslocamento e rotações do motor Energy needs of a planter at different travel and engine speeds

    Directory of Open Access Journals (Sweden)

    João Cleber Modernel da Silveira

    2013-03-01

    Full Text Available A velocidade de operação do trator influencia diversos aspectos, entre eles o consumo de combustível, a capacidade operacional e a qualidade de semeadura. Este trabalho teve como objetivo avaliar a demanda energética de um conjunto trator-semeadora-adubadora em sistema plantio direto, em função das velocidades de deslocamento e rotações no eixo do motor, na semeadura da cultura do milho. Os 12 tratamentos foram constituídos de quatro velocidades de deslocamento, obtidas em função dos escalonamentos de marchas e de três rotações do motor do trator. Durante a semeadura, monitoraram-se a velocidade de operação, a rotação do motor, a força de tração e o consumo horário de combustível. Os resultados mostraram que o requerimento de potência na barra de tração, média, por linha de semeadura, por profundidade do sulco e por área mobilizada aumentou com o aumento da velocidade de operação do conjunto mecanizado. O consumo horário de combustível foi elevado com o aumento da velocidade de operação e da rotação do motor, sendo menor na rotação do motor de 1.500 rpm.The operating speed of the tractor influences various aspects, including fuel consumption, operational capacity and sowing quality. This study aimed to assess the energy needs of a tractor-planter when sowing maize in a no-tillage system, according to its travel speed and the rotation speed of the motor shaft. The 12 treatments consisted of four travel speeds, obtained by staggering the gears, and three tractor-engine rotation speeds. During sowing, the speed of operation, engine speed, the traction force and hourly consumption of fuel were monitored. The results showed that the average power requirement on the drawbar per seeding row, groove depth, and worked area, increased with an increase in the operating speeds of the mechanism. Hourly fuel consumption went up with the increase in operating and engine-rotation speeds, being lowest at a speed of 1,500 rpm.

  14. Damped bead on a rotating circular hoop - a bifurcation zoo

    CERN Document Server

    Dutta, Shovan

    2012-01-01

    The evergreen problem of a bead on a rotating hoop shows a multitude of bifurcations when the bead moves with friction. This motion is studied for different values of the damping coefficient and rotational speeds of the hoop. Phase portraits and trajectories corresponding to all different modes of motion of the bead are presented. They illustrate the rich dynamics associated with this simple system. For some range of values of the damping coefficient and rotational speeds of the hoop, linear stability analysis of the equilibrium points is inadequate to classify their nature. A technique involving transformation of coordinates and order of magnitude arguments is presented to examine such cases. This may provide a general framework to investigate other complex systems.

  15. Effects of Clinostat Rotation on Aurelia Statolith Synthesis

    Science.gov (United States)

    Spangenberg, Dorothy B.; Davis, S.; Ross-Clunis, H., III

    1991-01-01

    Aurelia ephyrae develop eight graviceptors (rhopalia) during their metamorphosis from polyps, which are used for positional orientation with respect to gravity. In three experiments for each speed of 1/15, 1/8, 1/2, 1, and 24 rpm, groups of six polyps were rotated in the horizontal or vertical plane (control) using clinostats. Other controls were kept stationary in the two planes. Ten ephyrae from each group were collected after 5 to 6 days at 27 C in iodine and the number of statoliths per rhopalium were counted. Statistical analyses of statolith numbers revealed that horizontal clinostat rotation at 1/4 and 1/2 rpm caused the formation of significantly fewer statoliths per rhopalium than were found in controls. The finding that these slow rates of rotation reduces statolith numbers suggests that the developing ephyrae were disoriented with respect to gravity at these speeds, causing fewer statocytes to differentiate or to mineralize.

  16. Numerical and experimental study of rotating jet flows

    Science.gov (United States)

    Shin, Seungwon; Che, Zhizhao; Kahouadji, Lyes; Matar, Omar; Chergui, Jalel; Juric, Damir

    2015-11-01

    Rotating jets are investigated through experimental measurements and numerical simulations. The experiments are performed on a rotating jet rig and the effects of a range of parameters controlling the liquid jet are investigated, e.g. jet flow rate, rotation speed, jet diameter, etc. Different regimes of the jet morphology are identified, and the dependence on several dimensionless numbers is studied, e.g. Reynolds number, Weber number, etc. The breakup process of droplets is visualized through high speed imaging. Full three-dimensional direct numerical simulations are performed using BLUE, a massively parallel two-phase flow code. The novel interface algorithms in BLUE track the gas-liquid interface through a wide dynamic range including ligament formation, break up and rupture. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  17. Flight tests of a rotating cylinder flap on a North American Rockwell YOV-10 aircraft

    Science.gov (United States)

    Cichy, D. R.; Harris, J. W.; Mackay, J. K.

    1972-01-01

    Flight tests were conducted of a twin engine airplane modified to a STOL configuration with rotating cylinder flaps and interconnected propellers. The flight tests included verification of the functional operation of the rotating cylinder flap system and the determination of the low speed flying qualities and performance characteristics with emphasis on approach and landing.

  18. Review of High-Speed Fiber Optic Grating Sensors Systems

    Energy Technology Data Exchange (ETDEWEB)

    Udd, E; Benterou, J; May, C; Mihailov, S J; Lu, P

    2010-03-24

    Fiber grating sensors can be used to support a wide variety of high speed measurement applications. This includes measurements of vibrations on bridges, traffic monitoring on freeways, ultrasonic detection to support non-destructive tests on metal plates and providing details of detonation events. This paper provides a brief overview of some of the techniques that have been used to support high speed measurements using fiber grating sensors over frequency ranges from 10s of kHz, to MHZ and finally toward frequencies approaching the GHz regime. Very early in the development of fiber grating sensor systems it was realized that a high speed fiber grating sensor system could be realized by placing an optical filter that might be a fiber grating in front of a detector so that spectral changes in the reflection from a fiber grating were amplitude modulated. In principal the only limitation on this type of system involved the speed of the output detector which with the development of high speed communication links moved from the regime of 10s of MHz toward 10s of GHz. The earliest deployed systems involved civil structures including measurements of the strain fields on composite utility poles and missile bodies during break tests, bridges and freeways. This was followed by a series of developments that included high speed fiber grating sensors to support nondestructive testing via ultrasonic wave detection, high speed machining and monitoring ship hulls. Each of these applications involved monitoring mechanical motion of structures and thus interest was in speeds up to a few 10s of MHz. Most recently there has been interest in using fiber grating to monitor the very high speed events such as detonations and this has led to utilization of fiber gratings that are consumed during an event that may require detection speeds of hundreds of MHz and in the future multiple GHz.

  19. Rapidly rotating red giants

    CERN Document Server

    Gehan, Charlotte; Michel, Eric

    2016-01-01

    Stellar oscillations give seismic information on the internal properties of stars. Red giants are targets of interest since they present mixed modes, which behave as pressure modes in the convective envelope and as gravity modes in the radiative core. Mixed modes thus directly probe red giant cores, and allow in particular the study of their mean core rotation. The high-quality data obtained by CoRoT and Kepler satellites represent an unprecedented perspective to obtain thousands of measurements of red giant core rotation, in order to improve our understanding of stellar physics in deep stellar interiors. We developed an automated method to obtain such core rotation measurements and validated it for stars on the red giant branch. In this work, we particularly focus on the specific application of this method to red giants having a rapid core rotation. They show complex spectra where it is tricky to disentangle rotational splittings from mixed-mode period spacings. We demonstrate that the method based on the id...

  20. Modeling and control of surge and rotating stall in compressors

    Energy Technology Data Exchange (ETDEWEB)

    Gravdahl, Jan Tommy

    1998-12-31

    Compressors are used in power generation and a variety of other applications. This thesis contains new results in the field of modeling and control of rotating stall and surge in compressors. A close coupled valve is included in the Moore-Greitzer compression system model and controllers for both surge and rotating stall is derived using backstepping. Disturbances, constant and time varying, are then taken into account, and non-linear controllers are derived. Stability results are given. Then, passivity is used to derive a simple surge control law for the closed coupled valve. This propositional control law is shown to stabilize the system even in the presence of time varying disturbances in mass flow and pressure. A novel model for an axial compression system with non-constant compressor speed is derived by extending the Moore-Greitzer model. Rotating stall and surge is studied in connection with acceleration of the compressor. Finally, a model for a centrifugal compression system with time varying compressor speed is derived. The variable speed compressor characteristic is derived based on energy losses in the compressor components. Active control of surge in connection with varying speed is studied. Semi-global exponential stability of the compression system with both surge and speed control is proven. 103 refs., 38 figs., 5 tabs.